US20070268276A1 - Acoustic Touch Sensor with Low Profile Diffractive Grating Transducer Assembly - Google Patents
Acoustic Touch Sensor with Low Profile Diffractive Grating Transducer Assembly Download PDFInfo
- Publication number
- US20070268276A1 US20070268276A1 US10/561,873 US56187304A US2007268276A1 US 20070268276 A1 US20070268276 A1 US 20070268276A1 US 56187304 A US56187304 A US 56187304A US 2007268276 A1 US2007268276 A1 US 2007268276A1
- Authority
- US
- United States
- Prior art keywords
- substrate
- transducer
- acoustic
- grating
- canceled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/043—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves
- G06F3/0436—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
Definitions
- the field of the present invention relates to touch sensor technology, and more particularly to acoustic touch sensor technology.
- Touch sensors are transparent or opaque input devices for computers and other electronic systems. As the name suggests, touch sensors are activated by touch, either from a user's finger, or a stylus or some other device.
- a transparent touch sensor, and specifically a touchscreen is used in conjunction with a display device, such as cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, or other type of display, to form a touch display.
- CTR cathode ray tube
- LCD liquid crystal display
- plasma electroluminescent
- touch displays are increasingly used in commercial applications, such as restaurant order entry systems, industrial process control applications, interactive museum exhibits, public information kiosks, pagers, cellular phones, personal digital assistants, and video games.
- the dominant touch technologies presently in use are resistive, capacitive, infrared, and acoustic technologies.
- Touchscreens incorporating these technologies have delivered high standards of performance at competitive prices. All are transparent devices that respond to a touch by transmitting the touch position coordinates to a host computer.
- Acoustic touchscreens, also known as ultrasonic touchscreens have competed effectively with these other touch technologies. This is due in large part to the ability of acoustic touchscreens to handle demanding applications with high transparency and high resolution touch performance, while providing a durable touch surface.
- an acoustic touchscreen comprises a touch sensitive substrate in which an acoustic wave is propagated.
- a touch occurs on the substrate surface, it results in the absorption of at least a portion of the wave energy being propagated across the substrate.
- the touch position is determined using electronic circuitry to locate the absorption position in an XY coordinate system that is conceptually and invisibly superimposed onto the touchscreen. In essence, this is accomplished by recording the time the wave is initially propagated and the time at which a touch induced attenuation in the amplitude of the wave occurs. The difference in these times can then be used, together with the known speed of the wave through the substrate, to determine the precise location of the touch.
- a transparent touch sensor and specifically a touchscreen, is generally placed over a display device, such as cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, or other type of display.
- a display device such as cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, or other type of display.
- the touchscreen can be constructed directly on the front surface of the display device, so that the surface of the display device is touch sensitive. This latter construction is desirable because it eliminates a piece of glass or other material between the viewer and the display device, increasing the perceived display brightness and contrast ratio. Also, there are economic advantages in dispensing with an overlay glass and not having to modify the chassis of the display device to make room for the overlay glass.
- the acoustic touchscreen comprises an acoustic substrate and transducers, which are elements that convert energy from one form to another.
- a transmit transducer may receive a tone burst from associated electronic circuitry and then emit an acoustic wave across the substrate.
- a receive transducer may receive a transmitted acoustic wave from the substrate and generate an electronic signal that is transmitted to associated electronic circuitry for processing.
- acoustic transducer assemblies Various types are known. The most common types used in acoustic touchscreens are wedge transducer assemblies, grating transducer assemblies, and edge transducers.
- FIG. 1 (A) illustrates a typical wedge transducer assembly 10 a, which utilizes the phenomenon that acoustic waves are refracted when they are obliquely incident on a boundary surface of different media with appropriately differing wave velocities.
- the wedge transducer assembly 10 a consists of a wedge 12 (which can be made of plastic, for example) with its hypotenuse adhered to the front surface 18 of the acoustic substrate 16 , which is composed of a different material than that of the wedge 12 , e.g., glass.
- the wedge transducer assembly 10 a also comprises a transducer, and specifically a piezoelectric element 14 , mounted to a side of the wedge 12 other than the hypotenuse.
- the piezoelectric element 14 couples to a bulk wave in the wedge 12 , which propagates at the critical angle, i.e., the “wedge angle,” to refract to or from a horizontally propagating wave in the substrate 16 .
- FIG. 1 (B) illustrates a typical grating transducer assembly 10 b, which comprises a grating 22 composed of perturbation elements 24 , which are aligned in parallel strips along front substrate surface 18 .
- the grating transducer assembly 10 b also comprises a transducer, and specifically a piezoelectric element 26 , mounted on a rear surface 28 of the substrate 16 opposite the front substrate surface 18 .
- the piezoelectric element 26 couples to a bulk wave in the substrate 16 .
- This bulk wave couples, via the grating 22 , to two oppositely traveling horizontally propagating waves in the substrate 18 .
- Further details regarding the structure and use of grating transducers are disclosed in U.S. Pat. No. 6,091,406, which is expressly incorporated herein by reference.
- FIG. 1 (C) illustrates a typical edge transducer 10 c, which comprises a piezoelectric element 32 mounted directly on an edge 34 of the substrate 16 in such a manner that an acoustic wave with appreciable power at the front substrate surface 18 is generated.
- the interface thus serves the mechanical function of connecting the piezoelectric element 32 to the substrate 16 , as well as the acoustic function of coupling to a horizontally propagating wave in the substrate 16 , as illustrated by the arrows.
- Further details regarding the structure and use of edge transducers to excite horizontally polarized shear waves are disclosed in U.S. Pat. No. 5,177,327, which is expressly incorporated herein by reference.
- the selection of which transducer type to use will depend, at least in part, on the structural environment in which the touchscreen is to be mounted. For example, selection of the transducer type may depend on whether the acoustic substrate is either overlaid on the front panel of a display device to form a separate faceplate, or incorporated directly into the front panel of the display device. Selection of the transducer type may also depend on the shape of the acoustic substrate, e.g., whether it is curved or flat.
- FIG. 2 illustrates a touch display 50 that comprises a display device 52 and an acoustic substrate 54 that is overlaid onto the display device 52 .
- the display device 52 has a curved front panel 56 , such as in a typical cathode ray tube, and the acoustic substrate 54 has a corresponding curved shape. Due to the curved geometry of the acoustic substrate 54 , a space exists between the substrate 54 and a bezel 58 covering the periphery of the substrate 54 . In this case, a wedge transducer assembly 10 a , even with its relatively high profile, can be conveniently mounted on the front surface 60 of the substrate 54 within this space. Thus, wedge transducer assemblies 10 a may be used where it is possible or desirable to mount a transducer on the front surface 60 of the acoustic substrate 54 .
- FIG. 3 illustrates a touch display 70 that also comprises a display device 72 and an acoustic substrate 74 that is overlaid onto the display device 72 .
- the display device 72 has a flat front panel 76 , such as a liquid crystal display, a flat CRT or a plasma display, and the acoustic substrate 74 is also flat.
- a grating transducer assembly 10 b can be used despite the minimal clearance provided.
- the gratings 22 of the transducer assembly 10 b which have a relatively low profile, can be located on the front surface 80 of the substrate 74 within the minimal space provided between the bezel 58 and the substrate 74 .
- the piezoelectric element 26 can be located on the rear surface 82 of the substrate 74 .
- the rear substrate surface 82 may be beveled or inclined in order to provide clearance between the piezoelectric element 26 and the front panel 76 of the display device 72 .
- an edge transducer 10 c can be mounted to the substrate in this space.
- the requirement of a carefully machined vertical surface may add significant cost to this approach.
- edge transducers become more complex and thus less desirable.
- a touchscreen manufacturer can typically find a viable solution when selectively incorporating the above-described transducers 10 within an acoustic substrate that forms a separate faceplate, such may not be the case when the acoustic substrate forms the front panel of the display device, i.e., the display device, itself, has a touch sensitive front panel.
- the piezoelectric element of a grating transducer assembly must be placed on the rear surface of the acoustic substrate—an option not available when the substrate forms the front panel of the display device.
- the display device has touch sensitive front panel that is flat, e.g., a CRT or 50′′ plasma-display
- mounting of a wedge transducer assembly on the front surface of the display may be difficult, often resulting in mechanical interference between the bezel and the transducer. This interference may impede the proper functioning of the transducer, or worse yet, damage either the transducer or the bezel.
- the acoustic substrate forms a separate faceplate, it may be very difficult to provide a vertical machined surface for an edge transducer.
- a touchscreen manufacturer does not have the option to modify the housing in which the display device is enclosed.
- the touchscreen manufacturer In building a touchscreen that forms the faceplate of a display device, the touchscreen manufacturer normally does not manufacture the display device itself. Rather, the manufacturer works with the display device, as supplied by a monitor manufacturer. Since it is often impractical for the touchscreen manufacturer to replace the supplied housing with a new housing, the manufacturer must adapt to whatever space is available between the supplied housing and the display device for accommodating the touchscreen elements. Even where the touchscreen manufacturer has design control over the bezel, mechanical interference with the transducers often forces a reduction in the dimensions of the bezel opening that prevents one from utilizing the full available display area of the display device.
- a touch sensor comprises an acoustic substrate having a surface.
- the substrate is transparent, so that it can be used in conjunction with a display device.
- the touch sensor further comprises an acoustic transducer, which in one preferred embodiment, comprises a piezoelectric element.
- the touch sensor further comprises an acoustically diffractive grating disposed between the substrate and the transducer.
- the diffractive grating is configured to couple acoustic energy within the transducer to an acoustic wave propagating along the surface of the substrate.
- the grating can be disposed between the substrate and the transducer in any one of a variety of manners.
- the grating can be a structurally distinct element that is suitably adhered between the substrate and transducer.
- the grating can be structurally integrated with either or both of the transducer and substrate, e.g., formed on or into either or both of the surfaces of the transducer and substrate.
- a grating is between the substrate and transducer if an acoustic wave traveling along the surface of the substrate impinges on the grating before traveling through the transducer, or if an acoustic wave traveling from the transducer impinges on the grating before traveling across the surface of the substrate.
- the combination of the transducer and grating has a relatively low profile that allows the combination to more easily fit between the acoustic substrate and another structure, e.g., a bezel, placed in front of the substrate.
- the diffractive grating comprises an array of parallel elements.
- the elements are spaced from each other a distance equal to the wavelength of the acoustic wave propagating on the substrate surface. In this manner, the diffracted acoustic energy will combine together to form a stronger acoustic wave.
- the touch sensor may also comprise a second acoustic transducer, and a second acoustically diffractive grating disposed between the substrate and the second transducer.
- the second diffractive grating can couple acoustic energy within the second acoustic transducer to the acoustic wave.
- the first transducer and grating can transmit an acoustic wave across the surface of the substrate, and the second transducer and grating can receive the acoustic wave from the substrate surface.
- a touch display comprises a display device, e.g., a cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, vacuum fluorescent display (VFD), field emission display (FED), or other type of display.
- the touch display further comprises an acoustic touchscreen whose substrate is the front surface the display device, an acoustic transducer, and an acoustically diffractive grating disposed between the substrate and the transducer.
- the diffractive grating is configured to couple acoustic energy within the acoustic transducer to an acoustic wave propagating along the surface of the substrate.
- the diffractive grating, transducer, and substrate can include features similar to those previously described above. Notably, the low profile of the combined transducer and grating itself is well suited to display devices with flat integrated acoustic substrates that have very little space between the substrate and bezel.
- FIG. 1 (A) is a side view of a prior art wedge transducer assembly
- FIG. 1 (B) is a side view of a prior art grating transducer assembly
- FIG. 1 (C) is a side view of a prior art edge transducer
- FIG. 2 is a cross-sectional view of a prior art touch display having a display device with a curved front panel;
- FIG. 3 is a cross-sectional view of a prior art touch display having a display device with a flat front panel;
- FIG. 4 is a block diagram of a touchscreen system constructed in accordance with one preferred embodiment of the present invention.
- FIG. 5 is a top cross-sectional view of a touch display incorporating the touch screen system of FIG. 4 ;
- FIG. 6 is a close-up view of the touch display of FIG. 5 in the region indicated by line 6 - 6 ;
- FIG. 7 is a top view of one preferred embodiment of a grating that can be used in the touchscreen illustrated in FIG. 5 ;
- FIG. 8 is a side view of the grating of FIG. 7 used in the touchscreen illustrated in FIG. 5 ;
- FIG. 9 is a side view of another preferred embodiment of a grating used in the touchscreen illustrated in FIG. 5 ;
- FIG. 10 is a side view of still another preferred embodiment of a grating that can be used in the touchscreen illustrated in FIG. 5 ;
- FIG. 11 is a side view of yet another preferred embodiment of a grating that can be used in the touchscreen illustrated in FIG. 5 ;
- FIG. 12 is a side view of still yet another preferred embodiment of a grating that can be used in the touchscreen illustrated in FIG. 5 ;
- FIG. 13 is a side view of another preferred embodiment of a grating that can be used in the touchscreen illustrated in FIG. 5 .
- FIG. 14 (A) is a perspective view of a VFD touch display
- FIG. 14 (B) is a cross-sectional plan view of a VFD touch display, taken along line 303 - 303 ′ in FIG. 14 (A);
- FIG. 15 (A) is a perspective view of an FED touch display
- FIG. 15 (B) is a cross-sectional view of an FED touch display, taken along line 403 - 403 ′ in FIG. 15 (A).
- the touchscreen system 100 generally comprises an acoustic touchscreen 105 (i.e., a touch sensor having a transparent substrate), a controller 110 , and a lead 115 coupling the controller 110 to the touchscreen 105 .
- the touchscreen system 100 is configured to respond to a touch on the touchscreen 105 by causing acoustic signals to be transmitted across the touchscreen 105 , one or more of which are modulated in the presence of the touch.
- the controller 110 uses the modulated signal to identify the location on the touchscreen 105 where the touch occurred.
- the controller 110 If the controller 110 identifies a touch as valid, it transmits the position of the touch to a host computer (not shown) that then implements a corresponding computer function to display the pertinent information on a display device (shown in FIG. 5 ), for example, graphics such as an icon or a menu or directory from which the user can select options.
- the touchscreen 105 comprises an acoustic substrate 120 having a front surface 135 and a plurality of transducer assemblies 125 mounted to the front substrate surface 135 .
- transducer assemblies 125 are used, two of which are operated by the controller 110 to transmit the acoustic signals across the front substrate surface 135 in respective orthogonal directions, and the other two of which are operated by the controller 110 to receive the acoustic signals from the front substrate surface 135 .
- These ultrasound signals form a grid that allows the controller 110 to determine the position of the touch on the substrate 120 . Further details on the general use and construction of acoustic touchscreen systems to identify and locate touches are disclosed in U.S. Pat. Nos. 3,673,327, 4,644,100 and 6,091,406, which are expressly incorporated herein by reference.
- the touchscreen system 100 can be used in conjunction with a conventional display device 155 to create a touch display 150 .
- the faceplate of the display device 155 serves as the substrate 120 of the touchscreen 105 .
- the touchscreen 105 is coupled via a cable 160 to an outlet 165 , which is to receive power from, and interface, with the controller 110 (shown in FIG. 4 ).
- the touch display 150 comprises a generally hollow monitor back case 170 , which receives the display device 155 and all of the associated circuitry and cables, and a bezel 175 , which covers and protects the touchscreen 105 and associated componentry.
- the acoustic substrate 120 has a generally flat rectangular geometry. Although the present invention is most beneficial in the context of acoustic substrates that form the flat faceplate of a display device, the present invention is generally applicable to all types of display devices.
- the touchscreen 105 can be disposed over a preexisting faceplate of a display device.
- the substrate 120 can have a non-rectangular shape, such as a hexagonal shape, and may alternatively be curved along one or both the X- and Y-axes.
- the substrate 120 itself is composed of a material that allows propagation of an acoustic wave through the substrate 120 in a direction parallel to the front substrate surface 135 at the operating frequency.
- the substrate 120 may conveniently be composed of the same material that the front surface of conventional display devices are often composed of (e.g., glass), the substrate 120 can be composed of other materials. Additionally, the substrate 120 need not be homogenous, but can be composed of a non-homogenous material, e.g., formed of different layers.
- the acoustic wave that propagates through the substrate 120 may be any type that is detectably perturbed by a touch on the front substrate surface 135 .
- Surface bound waves such as Rayleigh waves (which include quasi-Rayleigh waves), have excellent touch sensitivity and are inherently confined to a thin volume close to the surface even for a substrate of an arbitrarily large thickness.
- Horizontally polarized shear waves have the advantage that they weakly couple to liquid and gel-like contaminants, such as water and silicone-rubber seals.
- a non-homogenous substrate may, in addition to supporting propagation of other types of waves, be particularly adapted to support propagation of horizontally polarized shear waves having asymmetric surface power density, including Love waves, which are horizontally polarized shear waves trapped near the touch surface like Rayleigh waves. Lamb waves in a sufficiently thin substrate provide yet another option for the choice of acoustic wave mode. Various engineering trade-offs are involved in the optimal choice of acoustic mode for a given application.
- each of the transducer assemblies 125 comprises an acoustic transducer 180 and an acoustic diffraction grating 185 disposed between the substrate 120 and the transducer 180 .
- the transducer 180 most commonly is composed of piezoelectric material, such as lead zirconium titanate, lead titanate, or lithium niobate, the present invention is not be so limited.
- Any transducer that converts acoustic energy into another form of energy, or vice versa e.g., optoacoustic transducers, magnetoacoustic transducers, acousto-acoustic (converts energy between one acoustic mode and another), and thermoacoustic transducers, among others, are available.
- the transducer 180 typically takes the form of a thin rectangular element having conductive portions serving as electrodes with a piezoelectric responsive material therebetween. However, there is no requirement that the transducer 180 be rectangular, for example if the touchscreen surface does not have square corners the shape of the transducer can accommodate the geometry of available layout space.
- an oscillating voltage signal is applied to the electrodes of transducer 180 , the resulting electric field within the piezoelectric material, via the piezoelectric effect, causes the transducer 180 to vibrate, depending on the nature of the piezoelectric material, arrangement of the electrodes, and mechanical limitations or couplings. Conversely, if the transducer 180 is subjected to mechanical oscillations, an oscillating voltage will appear on the electrodes.
- the mode of the mechanical oscillations produced by the transducer 180 There are several options regarding the mode of the mechanical oscillations produced by the transducer 180 .
- a common choice is the lowest-order compression-expansion oscillation with respect to the thin dimension of the transducer 180 . Such an element couples to other acoustic modes with a significant longitudinal component.
- Another option is a lowest-order shear oscillation in which one electrode-bearing surface moves parallel to the opposite face in the opposite direction.
- Such a transducer 180 couples to other acoustic modes with shear components.
- the direction of shear motion can be designed to be any direction within the plane of the electrodes. More complex options are also possible, including use of higher order oscillations, such as third, fifth, seventh, etc.
- the transducer 180 is designed to have a resonant frequency at the operating frequency for the desired mode of oscillation, e.g., 5 MHz.
- the resonant frequency is the bulk pressure-wave velocity (in the piezoelectric material) divided by twice the thickness of the transducer 180 , so that the thickness of the transducer 180 is half of the bulk pressure wavelength.
- the resonant frequency is the bulk shear-wave velocity (in the piezoelectric material) divided by twice the thickness of the transducer 180 , so that the thickness of the transducer 180 is half of the bulk shear wavelength.
- the transducer 180 is a damped mechanical oscillator due to coupling to acoustic waves in the substrate 120 .
- the grating 185 is configured to couple the acoustic energy generated by the transducer 180 to the acoustic wave propagating horizontally across the substrate 120 (i.e., the acoustic wave propagating parallel to the substrate surface 135 ). To this end, the grating 185 comprises an array of periodic acoustic perturbation elements 190 that are capable of coupling acoustic wave modes. Unlike the prior art grating transducer assembly 10 b illustrated in FIG. 1 (B), there is no intermediate bulk wave that travels through the substrate 120 between the transducer 180 and grating 185 .
- the perturbation elements 190 are in direct contact with the surface of the transducer 180 , so that the acoustic energy is directly coupled between the transducer 180 and perturbation elements 190 .
- the media between the perturbation elements 190 inefficiently couples to the transducer 180 .
- this media is composed of air, but can be composed of other materials, such as epoxy, as long as the relative acoustic coupling characteristics of the perturbation elements 190 are significantly greater than those of the intervening media
- acoustic energy generated by the transducer assembly 125 (when operated in the transmit mode) via electrical signals is incident on the grating 185 and is converted into surface bound or plates waves.
- the surface bound or plate waves propagate in the substrate 120 in the directions of the X-axis and the Y-axis through a plurality of paths previously described above.
- the surface bound or plate waves are then incident on the grating 185 and then converted into acoustic energy that is received by the transducer 125 (when operated in the receive mode), which is in turn converted into electrical signals.
- each perturbation element 190 may be straight. Alternatively, each perturbation element 190 may also be curved, and such elements may act as acoustic lenses. Each perturbation element 190 may also be a dot or a short elongated segment that interacts only with a portion of the acoustic wave. Optionally, perturbation elements may be provided to scatter to two or more different acoustic waves, each potentially having a different wave mode or axis of propagation.
- the grating perturbation cycle i.e., the interval or pitch of the grating 185 may be selected within a range of, for instance, about 0.01 to 10 mm, preferably about 0.1 to 5 mm, and more preferably about 0.3 to 1 mm, according to the wavelength of the acoustic wave horizontally propagating through the substrate 120 . So that there is an additive effect between the diffracted acoustic waves, the pitch of the grating 185 is preferably equal to the wavelength of the horizontally propagating wave.
- the grating 185 will typically couple to two horizontally propagating waves traveling in opposite directions.
- the wave traveling to or from the center of the substrate 120 will be used by the touchscreen system 100 to determine the location of touches on the substrate 120 , while the wave traveling to or from the edge of the substrate 120 will be discarded.
- an acoustic reflector (not shown) can be placed between the grating 185 and the edge of the substrate 120 in order to reflect the acoustic wave back towards the grating 185 .
- the perturbation elements 190 should be as inelastic (i.e., difficult to compress or tense) as possible to provide efficient coupling of the acoustic energy from the transducer 180 to the substrate 120 . Since the compressibility of material is determined by the thickness of the element divided by the Young's modulus, the undesired compressibility of the element will be proportional to its thickness. As such, the smaller the Young's modulus of the material of which the perturbation elements 190 are composed, the thinner the perturbation elements 190 should be. Notably, even a relatively soft material, such as epoxy, can efficiently be used as a perturbation element 190 if it is thin enough.
- the perturbation elements 190 can either be composed of homogenous material or may be composed of several materials. In each case, the overall compressibility of the material should be considered in order to maximize acoustic coupling between the transducer 180 and substrate 120 .
- the grating 185 can be variously constructed between the transducer 180 and substrate 120 and each perturbation element 190 can take any one of a variety of cross-sectional shapes (e.g., semi-circular, triangular, rectangular, saw-tooth, etc.).
- the grating 185 can either be formed of a distinct assembly that is suitably adhered between the substrate 120 and transducer 180 , or integrated with the substrate 120 or transducer 180 , e.g., by forming it on or into the front substrate surface 135 or transducer 180 .
- the grating 185 may be formed using any one of a variety of processes. For example, the grating 185 can be formed by depositing glass frit by screen printing.
- the grating 185 may also be formed by etching, cutting or grinding, or laser ablation, or by other removal means.
- the grating 185 may also be formed by molding, hot stamping, or by post-fabrication modification of the properties of the substrate 120 or transducer 180 .
- the height and/or width of the individual perturbation elements may vary across the grating to balance reflectivity and transparency over the grating 185 .
- the combination of the grating 185 and transducer 180 should have a relatively low profile, so that the combination can fit between the substrate 120 and the bezel 145 , as illustrated in FIG. 5 .
- this can be easily accomplished, since the thickness of the grating 185 can be made much less than an acoustic wavelength, and the thickness of the transducer 180 will be half of the length of the relevant bulk wave.
- FIG. 7 illustrates a grating 185 a that comprises a metal foil 195 through which a negative pattern of the perturbation elements 190 is etched to form alternating tines 200 (perturbation elements) and slots 205 .
- a metal foil 195 through which a negative pattern of the perturbation elements 190 is etched to form alternating tines 200 (perturbation elements) and slots 205 .
- multiple sets of perturbation patterns can be etched into larger foil sheets, which can then be cut into smaller foils, each of which comprises a single perturbation pattern.
- the preferred thickness of the metal foil 195 is between 0.050 and 0.075 mm. Assuming a surface wave velocity of the horizontally propagating acoustic wave through the substrate 120 (composed of glass) of 3.16 mm/ ⁇ s and a frequency of 5.53 MHz., the relevant acoustic wavelength will be 0.571 mm.
- each tine 200 should be 0.286 mm wide, and each slot 205 should also be 0.286 mm wide in order to provide the grating 185 ( a ) with a 0.571 mm pitch (i.e., 0.571 mm between the centers of adjacent tines 200 ).
- the foil 195 can then be adhered to the underside of the transducer 180 using a suitable adhesive, such as epoxy, as illustrated in FIG. 8 .
- the resulting subassembly (transducer 180 and foil 195 ) is then suitably adhered to the front surface 135 of the substrate 120 .
- the cured cement layers should be no more than 0.025 mm thick, so that the elasticity of the grating 185 is not unduly increased. In cementing the structure together, it may be impossible to avoid filling the slots 205 wholly or partially with cement. Fortunately, this is not of critical importance, since the transmission of acoustic energy through the relatively soft adhesive is much less efficient than the transmission through the metal foil 195 .
- the slots 205 can be dimensioned and completely filled with epoxy or some other material with a low acoustic velocity, so that the acoustic energy coupled between the transducer 180 and the substrate 120 through the slots 205 is 180 degrees out-of-phase with the acoustic energy coupled between the transducer 180 and the substrate 120 through the tines 200 .
- the excitation of the desired waves on the substrate surface from this “parasitic” acoustic energy traveling through the slots 205 will constructively add to the acoustic energy diffracted by the tines 200 .
- the metal foil 195 may have to be made thicker in order to adjust the relative phase of the acoustic energy traveling through the slots 205 .
- FIG. 9 illustrates a grating 185 b that comprises a metal block 210 , e.g., aluminum, on which a grating pattern is provided, e.g., by hot stamping or coining, to form alternating ridges 215 (perturbation elements) aid grooves 220 .
- the metal block 210 is then adhered to the underside of the transducer 180 using a suitable adhesive, such as epoxy.
- the resulting subassembly is then suitably adhered to the front surface 135 of the substrate 120 .
- the cured cement layers should be no more than 0.025 mm thick, so that the elasticity of the grating 185 is not unduly increased.
- the metal block 210 is preferably one-half wavelength thick (which in aluminum, is 0.57 mm at 5.53 MHz), so that the acoustic energy is transferred between the transducer 180 and substrate 120 without changing impedances. If acoustic impedance matching is desired between unequal acoustic impedances of the transducer 180 and substrate 120 , the thickness of the metal block 210 can be adjusted to achieve the desired impedance matching.
- FIG. 10 illustrates a grating 185 c that is formed by depositing a material such as glass frit (e.g., a lead-oxide containing ceramic) on the front substrate surface 135 in accordance with a grating pattern to form alternating ridges 225 and grooves 230 . If needed, the substrate surface 135 may then be suitably processed to harden the grating material. The ridges 225 of the grating may then be partially ground down to ensure that all of the ridges 225 have an equal and proper height. The transducer 180 is then adhered to the flattened ridges 225 using a suitable adhesive, such as epoxy.
- a suitable adhesive such as epoxy
- the grating pattern can be printed on the front substrate surface 135 using a polymer ink.
- a grating 185 d can alternatively be formed by depositing glass frit or polymer ink on the bottom surface of the transducer 180 to form alternating ridges 235 and grooves 240 .
- FIG. 12 illustrates a grating 185 e that is formed on the front substrate surface 135 to form alternating ridges 245 and grooves 250 .
- the grooves 250 can be formed using any suitable means, e.g., chemical etching, grinding, sandblasting, laser ablation, etc.
- the transducer 180 is then adhered to the grooved substrate surface 135 using a suitable adhesive, such as epoxy. In bonding the transducer 180 to the substrate, it is desirable to avoid filling the grooves with the adhesive. If such filling cannot be avoided, the grooves 250 are preferably made deep enough to render the acoustic coupling between the adhesive and the transducer 180 negligible.
- the increased depth of the grooves 250 will accordingly increase the thickness of, and thus the compressibility, of the entranced adhesive.
- the size and depth of the grooves 250 can be designed, such that the acoustic energy traveling through the adhesive is 180 degrees out-of-phase with the acoustic energy traveling through the ridges 245 .
- a grating 185 f can alternatively be formed in the bottom surface of the transducer 180 to form alternating ridges 255 and 260 .
- VFD vacuum fluorescent displays
- FED field emission displays
- Examples of transducer assemblies that can be used in combination with VFD's and FED's include element 125 in FIG.
- touch system controller electronics can be provided on the same board as the display driver electronics.
- FIG. 14 (A) illustrates a VFD 299 combined with transducer assemblies 301 and reflector arrays 304 to form touch display 300
- FIG. 14 (B) shows a cross section of touch display 300 along line 303 - 303 ′.
- VFDs are commonly used where small displays are required, and are generally designed to be mounted to circuit boards using leads 307 .
- the VFD 299 includes a front glass substrate 302 that can function as the ultrasonic substrate to propagate acoustic waves.
- the VFD includes an evacuated region 305 bounded by front glass 302 , bottom glass 308 , and spacer walls 309 , and accessed with vacuum port 313 .
- the grid 306 (attached to leads 307 ), anode 310 , phosphor 311 and filaments 312 are all located within evacuated region 305 . Because region 305 is a high vacuum region and contains the display mechanism, it would be difficult to mount transducers to the back side of front glass 302 . While two transducer assemblies 301 are shown in FIGS. 14 (A) and ( 13 ) for one-dimensional touch sensing capability, a variety of known touchscreen design approaches may be applied to a VFD touch display, including designs with only one transducer assembly 301 and designs for two-dimensional touch sensing. Therefore, the use of transducers with diffractive gratings described herein that can be low profile and may be mounted to the top side of the front glass are particularly useful in making a touch display using a VFD.
- FIG. 15 (A) shows a FED 399 combined with transducer assemblies 401 and reflector arrays 404 to form touch display 400 .
- FIG. 15 (B) shows a cross-section display 400 along line 403 - 403 ′.
- the FED has a top anode substrate 402 (glass) that can be used to propagate acoustic waves and to function as the touch sensitive surface of the touch display, where the acoustic energy is generated by and coupled into substrate 402 by transducer assembly 401 .
- the FED has an evacuated region 405 bounded by anode substrate 402 , cathode substrate 408 , and spacer walls 409 . Inside the evacuated region 405 are transparent anode 410 , phosphor 411 , cones 412 , gate electrodes 413 disposed on insulating members 414 , and resistive layer 415 .
- FIG. 15 (A) and (B) show two transducer assemblies 401 for one-dimensional touch sensing capability
- a variety of known touchscreen design approaches may be applied to an FED touch display, including designs with only one transducer assembly 401 and designs for two-dimensional touch sensing.
- region 405 must be evacuated and contains the FED display mechanism, it would be difficult to mount transducers to the back side of anode glass substrate 402 , making the low profile transducer assemblies described herein particularly useful for combination with an FED to make a touch display.
Abstract
A touch sensor having an acoustic substrate, an acoustic transducer, and an acoustically diffractive grating is provided. The grating is disposed between the transducer and the substrate, so that acoustic energy from the transducer is coupled to an acoustic wave propagating along the surface of the substrate. If used in a display device, the combination of the transducer and grating may provide a low profile that allows the assembly to be more easily placed between the acoustic substrate and a bezel placed in front of the substrate. No acoustic components need be mounted on the rear surface of the substrate, allowing the acoustic substrate to be formed on the front surface of the display device.
Description
- The field of the present invention relates to touch sensor technology, and more particularly to acoustic touch sensor technology.
- Touch sensors are transparent or opaque input devices for computers and other electronic systems. As the name suggests, touch sensors are activated by touch, either from a user's finger, or a stylus or some other device. A transparent touch sensor, and specifically a touchscreen, is used in conjunction with a display device, such as cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, or other type of display, to form a touch display. These touch displays are increasingly used in commercial applications, such as restaurant order entry systems, industrial process control applications, interactive museum exhibits, public information kiosks, pagers, cellular phones, personal digital assistants, and video games.
- The dominant touch technologies presently in use are resistive, capacitive, infrared, and acoustic technologies. Touchscreens incorporating these technologies have delivered high standards of performance at competitive prices. All are transparent devices that respond to a touch by transmitting the touch position coordinates to a host computer. Acoustic touchscreens, also known as ultrasonic touchscreens, have competed effectively with these other touch technologies. This is due in large part to the ability of acoustic touchscreens to handle demanding applications with high transparency and high resolution touch performance, while providing a durable touch surface.
- Typically, an acoustic touchscreen comprises a touch sensitive substrate in which an acoustic wave is propagated. When a touch occurs on the substrate surface, it results in the absorption of at least a portion of the wave energy being propagated across the substrate. The touch position is determined using electronic circuitry to locate the absorption position in an XY coordinate system that is conceptually and invisibly superimposed onto the touchscreen. In essence, this is accomplished by recording the time the wave is initially propagated and the time at which a touch induced attenuation in the amplitude of the wave occurs. The difference in these times can then be used, together with the known speed of the wave through the substrate, to determine the precise location of the touch.
- A transparent touch sensor, and specifically a touchscreen, is generally placed over a display device, such as cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, or other type of display. Alternatively, the touchscreen can be constructed directly on the front surface of the display device, so that the surface of the display device is touch sensitive. This latter construction is desirable because it eliminates a piece of glass or other material between the viewer and the display device, increasing the perceived display brightness and contrast ratio. Also, there are economic advantages in dispensing with an overlay glass and not having to modify the chassis of the display device to make room for the overlay glass.
- The acoustic touchscreen comprises an acoustic substrate and transducers, which are elements that convert energy from one form to another. For example, a transmit transducer may receive a tone burst from associated electronic circuitry and then emit an acoustic wave across the substrate. A receive transducer may receive a transmitted acoustic wave from the substrate and generate an electronic signal that is transmitted to associated electronic circuitry for processing.
- Various types of acoustic transducer assemblies are known. The most common types used in acoustic touchscreens are wedge transducer assemblies, grating transducer assemblies, and edge transducers.
-
FIG. 1 (A) illustrates a typicalwedge transducer assembly 10 a, which utilizes the phenomenon that acoustic waves are refracted when they are obliquely incident on a boundary surface of different media with appropriately differing wave velocities. Based on this principle, thewedge transducer assembly 10 a consists of a wedge 12 (which can be made of plastic, for example) with its hypotenuse adhered to thefront surface 18 of theacoustic substrate 16, which is composed of a different material than that of thewedge 12, e.g., glass. Thewedge transducer assembly 10 a also comprises a transducer, and specifically apiezoelectric element 14, mounted to a side of thewedge 12 other than the hypotenuse. As illustrated by the arrows, thepiezoelectric element 14 couples to a bulk wave in thewedge 12, which propagates at the critical angle, i.e., the “wedge angle,” to refract to or from a horizontally propagating wave in thesubstrate 16. -
FIG. 1 (B) illustrates a typicalgrating transducer assembly 10 b, which comprises agrating 22 composed ofperturbation elements 24, which are aligned in parallel strips alongfront substrate surface 18. Thegrating transducer assembly 10 b also comprises a transducer, and specifically apiezoelectric element 26, mounted on arear surface 28 of thesubstrate 16 opposite thefront substrate surface 18. As illustrated by the arrows, thepiezoelectric element 26 couples to a bulk wave in thesubstrate 16. This bulk wave couples, via thegrating 22, to two oppositely traveling horizontally propagating waves in thesubstrate 18. Further details regarding the structure and use of grating transducers are disclosed in U.S. Pat. No. 6,091,406, which is expressly incorporated herein by reference. -
FIG. 1 (C) illustrates atypical edge transducer 10 c, which comprises apiezoelectric element 32 mounted directly on anedge 34 of thesubstrate 16 in such a manner that an acoustic wave with appreciable power at thefront substrate surface 18 is generated. The interface thus serves the mechanical function of connecting thepiezoelectric element 32 to thesubstrate 16, as well as the acoustic function of coupling to a horizontally propagating wave in thesubstrate 16, as illustrated by the arrows. Further details regarding the structure and use of edge transducers to excite horizontally polarized shear waves are disclosed in U.S. Pat. No. 5,177,327, which is expressly incorporated herein by reference. - Ultimately, the selection of which transducer type to use will depend, at least in part, on the structural environment in which the touchscreen is to be mounted. For example, selection of the transducer type may depend on whether the acoustic substrate is either overlaid on the front panel of a display device to form a separate faceplate, or incorporated directly into the front panel of the display device. Selection of the transducer type may also depend on the shape of the acoustic substrate, e.g., whether it is curved or flat.
- For example,
FIG. 2 illustrates atouch display 50 that comprises adisplay device 52 and anacoustic substrate 54 that is overlaid onto thedisplay device 52. Thedisplay device 52 has acurved front panel 56, such as in a typical cathode ray tube, and theacoustic substrate 54 has a corresponding curved shape. Due to the curved geometry of theacoustic substrate 54, a space exists between thesubstrate 54 and abezel 58 covering the periphery of thesubstrate 54. In this case, awedge transducer assembly 10 a, even with its relatively high profile, can be conveniently mounted on thefront surface 60 of thesubstrate 54 within this space. Thus, wedge transducer assemblies 10 a may be used where it is possible or desirable to mount a transducer on thefront surface 60 of theacoustic substrate 54. -
FIG. 3 illustrates atouch display 70 that also comprises adisplay device 72 and anacoustic substrate 74 that is overlaid onto thedisplay device 72. Thedisplay device 72, however, has aflat front panel 76, such as a liquid crystal display, a flat CRT or a plasma display, and theacoustic substrate 74 is also flat. As a result, there is no or very little clearance between thesubstrate 74 and thebezel 58. In this case, agrating transducer assembly 10 b can be used despite the minimal clearance provided. Thegratings 22 of thetransducer assembly 10 b, which have a relatively low profile, can be located on thefront surface 80 of thesubstrate 74 within the minimal space provided between thebezel 58 and thesubstrate 74. Thepiezoelectric element 26 can be located on therear surface 82 of thesubstrate 74. Therear substrate surface 82 may be beveled or inclined in order to provide clearance between thepiezoelectric element 26 and thefront panel 76 of thedisplay device 72. - In touch displays where there is peripheral space available between the
bezel 58 and the edges of the acoustic substrate, anedge transducer 10 c can be mounted to the substrate in this space. However, the requirement of a carefully machined vertical surface may add significant cost to this approach. Furthermore, if coupling to Rayleigh waves is desired, edge transducers become more complex and thus less desirable. - Although a touchscreen manufacturer can typically find a viable solution when selectively incorporating the above-described
transducers 10 within an acoustic substrate that forms a separate faceplate, such may not be the case when the acoustic substrate forms the front panel of the display device, i.e., the display device, itself, has a touch sensitive front panel. For example, the piezoelectric element of a grating transducer assembly must be placed on the rear surface of the acoustic substrate—an option not available when the substrate forms the front panel of the display device. In the case where the display device has touch sensitive front panel that is flat, e.g., a CRT or 50″ plasma-display, mounting of a wedge transducer assembly on the front surface of the display may be difficult, often resulting in mechanical interference between the bezel and the transducer. This interference may impede the proper functioning of the transducer, or worse yet, damage either the transducer or the bezel. Much more so than the case where the acoustic substrate forms a separate faceplate, it may be very difficult to provide a vertical machined surface for an edge transducer. - Often, a touchscreen manufacturer does not have the option to modify the housing in which the display device is enclosed. In building a touchscreen that forms the faceplate of a display device, the touchscreen manufacturer normally does not manufacture the display device itself. Rather, the manufacturer works with the display device, as supplied by a monitor manufacturer. Since it is often impractical for the touchscreen manufacturer to replace the supplied housing with a new housing, the manufacturer must adapt to whatever space is available between the supplied housing and the display device for accommodating the touchscreen elements. Even where the touchscreen manufacturer has design control over the bezel, mechanical interference with the transducers often forces a reduction in the dimensions of the bezel opening that prevents one from utilizing the full available display area of the display device.
- There thus remains a need to provide a relatively low-profile transducer that can be mounted on the front surface of an acoustic substrate.
- In accordance with a first aspect of the present invention, a touch sensor is provided. The touch sensor comprises an acoustic substrate having a surface. In one preferred embodiment, the substrate is transparent, so that it can be used in conjunction with a display device. The touch sensor further comprises an acoustic transducer, which in one preferred embodiment, comprises a piezoelectric element. The touch sensor further comprises an acoustically diffractive grating disposed between the substrate and the transducer. The diffractive grating is configured to couple acoustic energy within the transducer to an acoustic wave propagating along the surface of the substrate. The grating can be disposed between the substrate and the transducer in any one of a variety of manners. For example, the grating can be a structurally distinct element that is suitably adhered between the substrate and transducer. Or the grating can be structurally integrated with either or both of the transducer and substrate, e.g., formed on or into either or both of the surfaces of the transducer and substrate. Thus, it can be appreciated that, for the purposes of this specification, a grating is between the substrate and transducer if an acoustic wave traveling along the surface of the substrate impinges on the grating before traveling through the transducer, or if an acoustic wave traveling from the transducer impinges on the grating before traveling across the surface of the substrate. Although the present invention should not be so limited in its broadest aspects, the combination of the transducer and grating has a relatively low profile that allows the combination to more easily fit between the acoustic substrate and another structure, e.g., a bezel, placed in front of the substrate.
- In one preferred embodiment, the diffractive grating comprises an array of parallel elements. Preferably, the elements are spaced from each other a distance equal to the wavelength of the acoustic wave propagating on the substrate surface. In this manner, the diffracted acoustic energy will combine together to form a stronger acoustic wave. The touch sensor may also comprise a second acoustic transducer, and a second acoustically diffractive grating disposed between the substrate and the second transducer. In this case, the second diffractive grating can couple acoustic energy within the second acoustic transducer to the acoustic wave. Thus, the first transducer and grating can transmit an acoustic wave across the surface of the substrate, and the second transducer and grating can receive the acoustic wave from the substrate surface.
- In accordance with a second aspect of the present invention, a touch display is provided. The touch display comprises a display device, e.g., a cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescent, vacuum fluorescent display (VFD), field emission display (FED), or other type of display. The touch display further comprises an acoustic touchscreen whose substrate is the front surface the display device, an acoustic transducer, and an acoustically diffractive grating disposed between the substrate and the transducer. As previously described, the diffractive grating is configured to couple acoustic energy within the acoustic transducer to an acoustic wave propagating along the surface of the substrate. The diffractive grating, transducer, and substrate can include features similar to those previously described above. Notably, the low profile of the combined transducer and grating itself is well suited to display devices with flat integrated acoustic substrates that have very little space between the substrate and bezel.
- The drawings illustrate the design and utility of a preferred embodiment of the present invention, in which similar elements are referred to by common reference numerals. In order to better appreciate the advantages and objects of the present invention, reference should be made to the accompanying drawings that illustrate this preferred embodiment. However, the drawings depict only one embodiment of the invention, and should not be taken as limiting its scope. With this caveat, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
-
FIG. 1 (A) is a side view of a prior art wedge transducer assembly; -
FIG. 1 (B) is a side view of a prior art grating transducer assembly; -
FIG. 1 (C) is a side view of a prior art edge transducer; -
FIG. 2 is a cross-sectional view of a prior art touch display having a display device with a curved front panel; -
FIG. 3 is a cross-sectional view of a prior art touch display having a display device with a flat front panel; -
FIG. 4 is a block diagram of a touchscreen system constructed in accordance with one preferred embodiment of the present invention; -
FIG. 5 is a top cross-sectional view of a touch display incorporating the touch screen system ofFIG. 4 ; -
FIG. 6 is a close-up view of the touch display ofFIG. 5 in the region indicated by line 6-6; -
FIG. 7 is a top view of one preferred embodiment of a grating that can be used in the touchscreen illustrated inFIG. 5 ; -
FIG. 8 is a side view of the grating ofFIG. 7 used in the touchscreen illustrated inFIG. 5 ; -
FIG. 9 is a side view of another preferred embodiment of a grating used in the touchscreen illustrated inFIG. 5 ; -
FIG. 10 is a side view of still another preferred embodiment of a grating that can be used in the touchscreen illustrated inFIG. 5 ; -
FIG. 11 is a side view of yet another preferred embodiment of a grating that can be used in the touchscreen illustrated inFIG. 5 ; -
FIG. 12 is a side view of still yet another preferred embodiment of a grating that can be used in the touchscreen illustrated inFIG. 5 ; -
FIG. 13 is a side view of another preferred embodiment of a grating that can be used in the touchscreen illustrated inFIG. 5 . -
FIG. 14 (A) is a perspective view of a VFD touch display; -
FIG. 14 (B) is a cross-sectional plan view of a VFD touch display, taken along line 303-303′ inFIG. 14 (A); -
FIG. 15 (A) is a perspective view of an FED touch display; and -
FIG. 15 (B) is a cross-sectional view of an FED touch display, taken along line 403-403′ inFIG. 15 (A). - Referring now to
FIG. 4 , atouchscreen system 100 constructed in accordance with a preferred embodiment of the present invention is described. Thetouchscreen system 100 generally comprises an acoustic touchscreen 105 (i.e., a touch sensor having a transparent substrate), acontroller 110, and a lead 115 coupling thecontroller 110 to thetouchscreen 105. Thetouchscreen system 100 is configured to respond to a touch on thetouchscreen 105 by causing acoustic signals to be transmitted across thetouchscreen 105, one or more of which are modulated in the presence of the touch. Thecontroller 110 in turn uses the modulated signal to identify the location on thetouchscreen 105 where the touch occurred. If thecontroller 110 identifies a touch as valid, it transmits the position of the touch to a host computer (not shown) that then implements a corresponding computer function to display the pertinent information on a display device (shown inFIG. 5 ), for example, graphics such as an icon or a menu or directory from which the user can select options. - As illustrated in
FIG. 5 , thetouchscreen 105 comprises anacoustic substrate 120 having afront surface 135 and a plurality oftransducer assemblies 125 mounted to thefront substrate surface 135. Typically, four transducer assemblies 125 (only two shown inFIG. 5 ) are used, two of which are operated by thecontroller 110 to transmit the acoustic signals across thefront substrate surface 135 in respective orthogonal directions, and the other two of which are operated by thecontroller 110 to receive the acoustic signals from thefront substrate surface 135. These ultrasound signals form a grid that allows thecontroller 110 to determine the position of the touch on thesubstrate 120. Further details on the general use and construction of acoustic touchscreen systems to identify and locate touches are disclosed in U.S. Pat. Nos. 3,673,327, 4,644,100 and 6,091,406, which are expressly incorporated herein by reference. - As shown in
FIG. 5 , thetouchscreen system 100 can be used in conjunction with aconventional display device 155 to create atouch display 150. In this embodiment, the faceplate of thedisplay device 155 serves as thesubstrate 120 of thetouchscreen 105. Thetouchscreen 105 is coupled via acable 160 to anoutlet 165, which is to receive power from, and interface, with the controller 110 (shown inFIG. 4 ). Thetouch display 150 comprises a generally hollow monitor backcase 170, which receives thedisplay device 155 and all of the associated circuitry and cables, and abezel 175, which covers and protects thetouchscreen 105 and associated componentry. - In the illustrated embodiment, the
acoustic substrate 120 has a generally flat rectangular geometry. Although the present invention is most beneficial in the context of acoustic substrates that form the flat faceplate of a display device, the present invention is generally applicable to all types of display devices. For example, thetouchscreen 105 can be disposed over a preexisting faceplate of a display device. Thesubstrate 120 can have a non-rectangular shape, such as a hexagonal shape, and may alternatively be curved along one or both the X- and Y-axes. - The
substrate 120 itself is composed of a material that allows propagation of an acoustic wave through thesubstrate 120 in a direction parallel to thefront substrate surface 135 at the operating frequency. Although thesubstrate 120 may conveniently be composed of the same material that the front surface of conventional display devices are often composed of (e.g., glass), thesubstrate 120 can be composed of other materials. Additionally, thesubstrate 120 need not be homogenous, but can be composed of a non-homogenous material, e.g., formed of different layers. - The acoustic wave that propagates through the
substrate 120 may be any type that is detectably perturbed by a touch on thefront substrate surface 135. Many options exist for the choice of surface bound or plate wave modes. Surface bound waves, such as Rayleigh waves (which include quasi-Rayleigh waves), have excellent touch sensitivity and are inherently confined to a thin volume close to the surface even for a substrate of an arbitrarily large thickness. Horizontally polarized shear waves have the advantage that they weakly couple to liquid and gel-like contaminants, such as water and silicone-rubber seals. A non-homogenous substrate may, in addition to supporting propagation of other types of waves, be particularly adapted to support propagation of horizontally polarized shear waves having asymmetric surface power density, including Love waves, which are horizontally polarized shear waves trapped near the touch surface like Rayleigh waves. Lamb waves in a sufficiently thin substrate provide yet another option for the choice of acoustic wave mode. Various engineering trade-offs are involved in the optimal choice of acoustic mode for a given application. - As best shown in
FIG. 6 , each of thetransducer assemblies 125 comprises anacoustic transducer 180 and anacoustic diffraction grating 185 disposed between thesubstrate 120 and thetransducer 180. Although thetraducer 180 most commonly is composed of piezoelectric material, such as lead zirconium titanate, lead titanate, or lithium niobate, the present invention is not be so limited. Any transducer that converts acoustic energy into another form of energy, or vice versa (e.g., optoacoustic transducers, magnetoacoustic transducers, acousto-acoustic (converts energy between one acoustic mode and another), and thermoacoustic transducers, among others, are available. - The
transducer 180 typically takes the form of a thin rectangular element having conductive portions serving as electrodes with a piezoelectric responsive material therebetween. However, there is no requirement that thetransducer 180 be rectangular, for example if the touchscreen surface does not have square corners the shape of the transducer can accommodate the geometry of available layout space. When an oscillating voltage signal is applied to the electrodes oftransducer 180, the resulting electric field within the piezoelectric material, via the piezoelectric effect, causes thetransducer 180 to vibrate, depending on the nature of the piezoelectric material, arrangement of the electrodes, and mechanical limitations or couplings. Conversely, if thetransducer 180 is subjected to mechanical oscillations, an oscillating voltage will appear on the electrodes. - There are several options regarding the mode of the mechanical oscillations produced by the
transducer 180. A common choice is the lowest-order compression-expansion oscillation with respect to the thin dimension of thetransducer 180. Such an element couples to other acoustic modes with a significant longitudinal component. Another option is a lowest-order shear oscillation in which one electrode-bearing surface moves parallel to the opposite face in the opposite direction. Such atransducer 180 couples to other acoustic modes with shear components. The direction of shear motion can be designed to be any direction within the plane of the electrodes. More complex options are also possible, including use of higher order oscillations, such as third, fifth, seventh, etc. - The
transducer 180 is designed to have a resonant frequency at the operating frequency for the desired mode of oscillation, e.g., 5 MHz. For lowest order compression or pressure oscillation, the resonant frequency is the bulk pressure-wave velocity (in the piezoelectric material) divided by twice the thickness of thetransducer 180, so that the thickness of thetransducer 180 is half of the bulk pressure wavelength. Similarly, for lowest order shear oscillation, the resonant frequency is the bulk shear-wave velocity (in the piezoelectric material) divided by twice the thickness of thetransducer 180, so that the thickness of thetransducer 180 is half of the bulk shear wavelength. As used in atouchscreen 105, thetransducer 180 is a damped mechanical oscillator due to coupling to acoustic waves in thesubstrate 120. - The grating 185 is configured to couple the acoustic energy generated by the
transducer 180 to the acoustic wave propagating horizontally across the substrate 120 (i.e., the acoustic wave propagating parallel to the substrate surface 135). To this end, thegrating 185 comprises an array of periodicacoustic perturbation elements 190 that are capable of coupling acoustic wave modes. Unlike the prior art gratingtransducer assembly 10 b illustrated inFIG. 1 (B), there is no intermediate bulk wave that travels through thesubstrate 120 between thetransducer 180 and grating 185. Rather, theperturbation elements 190 are in direct contact with the surface of thetransducer 180, so that the acoustic energy is directly coupled between thetransducer 180 andperturbation elements 190. To maximize the coupling of acoustic energy between thetransducer 180 and theperturbation elements 190, and thus the diffractive nature of the grating 185, the media between theperturbation elements 190 inefficiently couples to thetransducer 180. Preferably, this media is composed of air, but can be composed of other materials, such as epoxy, as long as the relative acoustic coupling characteristics of theperturbation elements 190 are significantly greater than those of the intervening media - Thus, it can be appreciated that acoustic energy generated by the transducer assembly 125 (when operated in the transmit mode) via electrical signals is incident on the
grating 185 and is converted into surface bound or plates waves. The surface bound or plate waves propagate in thesubstrate 120 in the directions of the X-axis and the Y-axis through a plurality of paths previously described above. The surface bound or plate waves are then incident on thegrating 185 and then converted into acoustic energy that is received by the transducer 125 (when operated in the receive mode), which is in turn converted into electrical signals. - In the illustrated embodiment, each
perturbation element 190 may be straight. Alternatively, eachperturbation element 190 may also be curved, and such elements may act as acoustic lenses. Eachperturbation element 190 may also be a dot or a short elongated segment that interacts only with a portion of the acoustic wave. Optionally, perturbation elements may be provided to scatter to two or more different acoustic waves, each potentially having a different wave mode or axis of propagation. - The grating perturbation cycle, i.e., the interval or pitch of the grating 185 may be selected within a range of, for instance, about 0.01 to 10 mm, preferably about 0.1 to 5 mm, and more preferably about 0.3 to 1 mm, according to the wavelength of the acoustic wave horizontally propagating through the
substrate 120. So that there is an additive effect between the diffracted acoustic waves, the pitch of the grating 185 is preferably equal to the wavelength of the horizontally propagating wave. - Notably, the grating 185 will typically couple to two horizontally propagating waves traveling in opposite directions. The wave traveling to or from the center of the
substrate 120 will be used by thetouchscreen system 100 to determine the location of touches on thesubstrate 120, while the wave traveling to or from the edge of thesubstrate 120 will be discarded. Optionally, an acoustic reflector (not shown) can be placed between the grating 185 and the edge of thesubstrate 120 in order to reflect the acoustic wave back towards the grating 185. - As a general rule, the
perturbation elements 190 should be as inelastic (i.e., difficult to compress or tense) as possible to provide efficient coupling of the acoustic energy from thetransducer 180 to thesubstrate 120. Since the compressibility of material is determined by the thickness of the element divided by the Young's modulus, the undesired compressibility of the element will be proportional to its thickness. As such, the smaller the Young's modulus of the material of which theperturbation elements 190 are composed, the thinner theperturbation elements 190 should be. Notably, even a relatively soft material, such as epoxy, can efficiently be used as aperturbation element 190 if it is thin enough. Theperturbation elements 190 can either be composed of homogenous material or may be composed of several materials. In each case, the overall compressibility of the material should be considered in order to maximize acoustic coupling between thetransducer 180 andsubstrate 120. - As will be described in further detail below, the grating 185 can be variously constructed between the
transducer 180 andsubstrate 120 and eachperturbation element 190 can take any one of a variety of cross-sectional shapes (e.g., semi-circular, triangular, rectangular, saw-tooth, etc.). The grating 185 can either be formed of a distinct assembly that is suitably adhered between thesubstrate 120 andtransducer 180, or integrated with thesubstrate 120 ortransducer 180, e.g., by forming it on or into thefront substrate surface 135 ortransducer 180. The grating 185 may be formed using any one of a variety of processes. For example, the grating 185 can be formed by depositing glass frit by screen printing. The grating 185 may also be formed by etching, cutting or grinding, or laser ablation, or by other removal means. The grating 185 may also be formed by molding, hot stamping, or by post-fabrication modification of the properties of thesubstrate 120 ortransducer 180. The height and/or width of the individual perturbation elements may vary across the grating to balance reflectivity and transparency over thegrating 185. - Significantly, the combination of the grating 185 and
transducer 180 should have a relatively low profile, so that the combination can fit between thesubstrate 120 and thebezel 145, as illustrated inFIG. 5 . Typically, this can be easily accomplished, since the thickness of the grating 185 can be made much less than an acoustic wavelength, and the thickness of thetransducer 180 will be half of the length of the relevant bulk wave. -
FIG. 7 illustrates a grating 185 a that comprises ametal foil 195 through which a negative pattern of theperturbation elements 190 is etched to form alternating tines 200 (perturbation elements) andslots 205. For purposes of manufacturing efficiency, multiple sets of perturbation patterns can be etched into larger foil sheets, which can then be cut into smaller foils, each of which comprises a single perturbation pattern. The preferred thickness of themetal foil 195 is between 0.050 and 0.075 mm. Assuming a surface wave velocity of the horizontally propagating acoustic wave through the substrate 120 (composed of glass) of 3.16 mm/μs and a frequency of 5.53 MHz., the relevant acoustic wavelength will be 0.571 mm. Accordingly, eachtine 200 should be 0.286 mm wide, and eachslot 205 should also be 0.286 mm wide in order to provide the grating 185(a) with a 0.571 mm pitch (i.e., 0.571 mm between the centers of adjacent tines 200). - After the etching process is completed, the
foil 195 can then be adhered to the underside of thetransducer 180 using a suitable adhesive, such as epoxy, as illustrated inFIG. 8 . The resulting subassembly (transducer 180 and foil 195) is then suitably adhered to thefront surface 135 of thesubstrate 120. Preferably, the cured cement layers should be no more than 0.025 mm thick, so that the elasticity of the grating 185 is not unduly increased. In cementing the structure together, it may be impossible to avoid filling theslots 205 wholly or partially with cement. Fortunately, this is not of critical importance, since the transmission of acoustic energy through the relatively soft adhesive is much less efficient than the transmission through themetal foil 195. - Alternatively, the
slots 205 can be dimensioned and completely filled with epoxy or some other material with a low acoustic velocity, so that the acoustic energy coupled between thetransducer 180 and thesubstrate 120 through theslots 205 is 180 degrees out-of-phase with the acoustic energy coupled between thetransducer 180 and thesubstrate 120 through thetines 200. In this manner, the excitation of the desired waves on the substrate surface from this “parasitic” acoustic energy traveling through theslots 205 will constructively add to the acoustic energy diffracted by thetines 200. In order to provide this effect, themetal foil 195 may have to be made thicker in order to adjust the relative phase of the acoustic energy traveling through theslots 205. -
FIG. 9 illustrates a grating 185 b that comprises ametal block 210, e.g., aluminum, on which a grating pattern is provided, e.g., by hot stamping or coining, to form alternating ridges 215 (perturbation elements)aid grooves 220. After the coining process is completed, themetal block 210 is then adhered to the underside of thetransducer 180 using a suitable adhesive, such as epoxy. The resulting subassembly (transducer 180 and metal block 210) is then suitably adhered to thefront surface 135 of thesubstrate 120. Again, the cured cement layers should be no more than 0.025 mm thick, so that the elasticity of the grating 185 is not unduly increased. Themetal block 210 is preferably one-half wavelength thick (which in aluminum, is 0.57 mm at 5.53 MHz), so that the acoustic energy is transferred between thetransducer 180 andsubstrate 120 without changing impedances. If acoustic impedance matching is desired between unequal acoustic impedances of thetransducer 180 andsubstrate 120, the thickness of themetal block 210 can be adjusted to achieve the desired impedance matching. -
FIG. 10 illustrates a grating 185 c that is formed by depositing a material such as glass frit (e.g., a lead-oxide containing ceramic) on thefront substrate surface 135 in accordance with a grating pattern to form alternatingridges 225 andgrooves 230. If needed, thesubstrate surface 135 may then be suitably processed to harden the grating material. Theridges 225 of the grating may then be partially ground down to ensure that all of theridges 225 have an equal and proper height. Thetransducer 180 is then adhered to the flattenedridges 225 using a suitable adhesive, such as epoxy. As an alternative to ceramic material such as glass frit, the grating pattern can be printed on thefront substrate surface 135 using a polymer ink. As illustrated inFIG. 11 , a grating 185 d can alternatively be formed by depositing glass frit or polymer ink on the bottom surface of thetransducer 180 to form alternatingridges 235 andgrooves 240. -
FIG. 12 illustrates a grating 185 e that is formed on thefront substrate surface 135 to form alternatingridges 245 andgrooves 250. Thegrooves 250 can be formed using any suitable means, e.g., chemical etching, grinding, sandblasting, laser ablation, etc. Thetransducer 180 is then adhered to the groovedsubstrate surface 135 using a suitable adhesive, such as epoxy. In bonding thetransducer 180 to the substrate, it is desirable to avoid filling the grooves with the adhesive. If such filling cannot be avoided, thegrooves 250 are preferably made deep enough to render the acoustic coupling between the adhesive and thetransducer 180 negligible. That is, the increased depth of thegrooves 250 will accordingly increase the thickness of, and thus the compressibility, of the entranced adhesive. Optionally, the size and depth of thegrooves 250 can be designed, such that the acoustic energy traveling through the adhesive is 180 degrees out-of-phase with the acoustic energy traveling through theridges 245. As illustrated inFIG. 13 , a grating 185 f can alternatively be formed in the bottom surface of thetransducer 180 to form alternatingridges - As stated above, the transducer/grating assemblies described herein may be used with any type of suitable display. Vacuum fluorescent displays (VFD) and field emission displays (FED) are examples of displays that can be used in combination with the transducer assemblies including diffractive gratings described above to make touch displays, wherein the diffractive gratings are used to couple acoustic energy from a transducer into a glass surface already present in an VFD or FED. Examples of transducer assemblies that can be used in combination with VFD's and FED's include
element 125 inFIG. 5 , andtransducer 180 combined with any of thegrating elements FIGS. 8-13 , respectively. In addition, touch system controller electronics can be provided on the same board as the display driver electronics. -
FIG. 14 (A) illustrates aVFD 299 combined withtransducer assemblies 301 andreflector arrays 304 to formtouch display 300, andFIG. 14 (B) shows a cross section oftouch display 300 along line 303-303′. VFDs are commonly used where small displays are required, and are generally designed to be mounted to circuit boards using leads 307. TheVFD 299 includes afront glass substrate 302 that can function as the ultrasonic substrate to propagate acoustic waves. The VFD includes an evacuatedregion 305 bounded byfront glass 302,bottom glass 308, andspacer walls 309, and accessed withvacuum port 313. The grid 306 (attached to leads 307),anode 310,phosphor 311 andfilaments 312 are all located within evacuatedregion 305. Becauseregion 305 is a high vacuum region and contains the display mechanism, it would be difficult to mount transducers to the back side offront glass 302. While twotransducer assemblies 301 are shown in FIGS. 14(A) and (13) for one-dimensional touch sensing capability, a variety of known touchscreen design approaches may be applied to a VFD touch display, including designs with only onetransducer assembly 301 and designs for two-dimensional touch sensing. Therefore, the use of transducers with diffractive gratings described herein that can be low profile and may be mounted to the top side of the front glass are particularly useful in making a touch display using a VFD. - In manner similar to that described above for a VFD, an FED can be made into a touch display using diffractive gratings described herein. FEDs are typically small flat panel displays, and can be used for a variety of applications where LCDs are used, e.g., in portable electronics.
FIG. 15 (A) shows aFED 399 combined withtransducer assemblies 401 andreflector arrays 404 to formtouch display 400.FIG. 15 (B) shows across-section display 400 along line 403-403′. The FED has a top anode substrate 402 (glass) that can be used to propagate acoustic waves and to function as the touch sensitive surface of the touch display, where the acoustic energy is generated by and coupled intosubstrate 402 bytransducer assembly 401. The FED has an evacuatedregion 405 bounded byanode substrate 402,cathode substrate 408, andspacer walls 409. Inside the evacuatedregion 405 aretransparent anode 410,phosphor 411,cones 412,gate electrodes 413 disposed on insulatingmembers 414, andresistive layer 415. Although FIGS. 15(A) and (B) show twotransducer assemblies 401 for one-dimensional touch sensing capability, a variety of known touchscreen design approaches may be applied to an FED touch display, including designs with only onetransducer assembly 401 and designs for two-dimensional touch sensing. Becauseregion 405 must be evacuated and contains the FED display mechanism, it would be difficult to mount transducers to the back side ofanode glass substrate 402, making the low profile transducer assemblies described herein particularly useful for combination with an FED to make a touch display. - Although particular embodiments of the present invention have been shown and described, it should be understood that the above discussion is not intended to limit the present invention to these embodiments. It will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Thus, the present invention is intended to cover alternatives, modifications, and equivalents that may fall within the spirit and scope of the present invention as defined by the claims.
Claims (21)
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. A touch display, comprising:
a display device comprising a vacuum fluorescent display or a field emission display;
a transparent acoustic substrate having a surface, the substrate forming a front surface of the display device;
an acoustic transducer; and
an acoustically diffractive grating disposed between the substrate and the transducer, the diffractive grating coupling acoustic energy within the acoustic transducer to an acoustic wave propagating along the surface of the substrate.
12. The touch display of claim 11 , wherein the diffractive grating comprises an array of parallel elements.
13. The touch display of claim 11 , wherein the elements are spaced from each other a distance equal to the wavelength of the acoustic wave.
14. The touch display of claim 11 , wherein the diffractive grating is structurally distinct from the transducer and substrate.
15. The touch display of claim 11 , wherein the diffractive grating is formed structurally integrated with the substrate.
16. The touch display of claim 11 , wherein the diffractive grating is structurally integrated with the transducer.
17. The touch display of claim 11 , further comprising:
another acoustic transducer; and
another acoustically diffractive grating disposed between the substrate and the other transducer, the other diffractive grating coupling acoustic energy within the other acoustic transducer to the acoustic wave.
18. The touch display of claim 11 , wherein the substrate surface is substantially flat.
19. The touch display of claim 11 , wherein the transducer comprises a piezoelectric element.
20. The touch display of claim 11 , wherein the grating comprises alternating tines and slots, and wherein the coupling between the transducer and the substrate through the tines is approximately 180 degrees out of phase with the coupling between the transducer and the substrate through the slots.
21. (canceled)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/561,873 US20070268276A1 (en) | 2003-06-24 | 2004-05-26 | Acoustic Touch Sensor with Low Profile Diffractive Grating Transducer Assembly |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/603,514 US7119800B2 (en) | 2003-06-24 | 2003-06-24 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
US10603514 | 2003-06-24 | ||
US10/561,873 US20070268276A1 (en) | 2003-06-24 | 2004-05-26 | Acoustic Touch Sensor with Low Profile Diffractive Grating Transducer Assembly |
PCT/US2004/016908 WO2005006242A2 (en) | 2003-06-24 | 2004-05-26 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070268276A1 true US20070268276A1 (en) | 2007-11-22 |
Family
ID=33539754
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/603,514 Active 2024-05-11 US7119800B2 (en) | 2003-06-24 | 2003-06-24 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
US10/561,873 Abandoned US20070268276A1 (en) | 2003-06-24 | 2004-05-26 | Acoustic Touch Sensor with Low Profile Diffractive Grating Transducer Assembly |
US11/544,188 Expired - Fee Related US7456825B2 (en) | 2003-06-24 | 2006-10-06 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/603,514 Active 2024-05-11 US7119800B2 (en) | 2003-06-24 | 2003-06-24 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/544,188 Expired - Fee Related US7456825B2 (en) | 2003-06-24 | 2006-10-06 | Acoustic touch sensor with low-profile diffractive grating transducer assembly |
Country Status (9)
Country | Link |
---|---|
US (3) | US7119800B2 (en) |
EP (2) | EP1639442B1 (en) |
JP (1) | JP4806632B2 (en) |
CN (1) | CN100426205C (en) |
AU (1) | AU2004255825A1 (en) |
CA (1) | CA2529715A1 (en) |
MX (1) | MXPA05014027A (en) |
TW (1) | TW200516501A (en) |
WO (1) | WO2005006242A2 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011126674A2 (en) * | 2010-03-30 | 2011-10-13 | Flextronics Ap, Llc | Simplified mechanical design for an acoustic touch screen |
US8209861B2 (en) | 2008-12-05 | 2012-07-03 | Flextronics Ap, Llc | Method for manufacturing a touch screen sensor assembly |
US8228306B2 (en) | 2008-07-23 | 2012-07-24 | Flextronics Ap, Llc | Integration design for capacitive touch panels and liquid crystal displays |
US8274486B2 (en) | 2008-12-22 | 2012-09-25 | Flextronics Ap, Llc | Diamond pattern on a single layer |
US8525955B2 (en) | 2012-01-31 | 2013-09-03 | Multek Display (Hong Kong) Limited | Heater for liquid crystal display |
US9128568B2 (en) | 2008-07-30 | 2015-09-08 | New Vision Display (Shenzhen) Co., Limited | Capacitive touch panel with FPC connector electrically coupled to conductive traces of face-to-face ITO pattern structure in single plane |
Families Citing this family (42)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050248548A1 (en) | 2004-04-14 | 2005-11-10 | Masahiro Tsumura | Acoustic touch sensor |
US20070239041A1 (en) * | 2006-03-28 | 2007-10-11 | The Johns Hopkins University | Non-invasive Venous Pressure Measurement |
US7764276B2 (en) * | 2006-04-18 | 2010-07-27 | Schermerhorn Jerry D | Touch control system and apparatus with multiple acoustic coupled substrates |
US20070270720A1 (en) * | 2006-05-04 | 2007-11-22 | Fry William R | Noninvasive physiologic pressure measurement |
US20080015436A1 (en) * | 2006-07-13 | 2008-01-17 | Misonix, Incorporated | High intensity focused ultrasound method and associated apparatus |
EP2017703A1 (en) * | 2007-07-09 | 2009-01-21 | Sensitive Object | Touch control system and method for localising an excitation |
US20100298051A1 (en) * | 2007-10-22 | 2010-11-25 | Wms Gaming Inc. | Wagering game table audio system |
US20110200211A1 (en) * | 2008-10-09 | 2011-08-18 | Robert Katz | Acoustics transmission fidelity augmentation interface for inertial type audio transducers |
US8576202B2 (en) | 2010-03-25 | 2013-11-05 | Elo Touch Solutions, Inc. | Bezel-less acoustic touch apparatus |
US9704473B2 (en) * | 2010-12-10 | 2017-07-11 | Palo Alto Research Center Incorporated | Variable acoustic grating based on changing acoustic impedances |
US9477350B2 (en) | 2011-04-26 | 2016-10-25 | Sentons Inc. | Method and apparatus for active ultrasonic touch devices |
US9189109B2 (en) | 2012-07-18 | 2015-11-17 | Sentons Inc. | Detection of type of object used to provide a touch contact input |
US11327599B2 (en) | 2011-04-26 | 2022-05-10 | Sentons Inc. | Identifying a contact type |
US9639213B2 (en) | 2011-04-26 | 2017-05-02 | Sentons Inc. | Using multiple signals to detect touch input |
US10198097B2 (en) | 2011-04-26 | 2019-02-05 | Sentons Inc. | Detecting touch input force |
US10019112B2 (en) | 2011-10-25 | 2018-07-10 | Semiconductor Components Industries, Llc | Touch panels with dynamic zooming and low profile bezels |
US9348467B2 (en) | 2011-11-15 | 2016-05-24 | Elo Touch Solutions, Inc. | Radial layout for acoustic wave touch sensor |
US9304629B2 (en) | 2011-11-15 | 2016-04-05 | Elo Touch Solutions, Inc. | Radial transducer for acoustic wave touch sensor |
US10235004B1 (en) | 2011-11-18 | 2019-03-19 | Sentons Inc. | Touch input detector with an integrated antenna |
KR101960836B1 (en) | 2011-11-18 | 2019-03-22 | 센톤스 아이엔씨. | Localized haptic feedback |
KR101803261B1 (en) | 2011-11-18 | 2017-11-30 | 센톤스 아이엔씨. | Detecting touch input force |
GB2498213B (en) * | 2012-01-09 | 2018-11-21 | Bae Systems Plc | Transducer arrangement |
US9348468B2 (en) | 2013-06-07 | 2016-05-24 | Sentons Inc. | Detecting multi-touch inputs |
US9078066B2 (en) | 2012-07-18 | 2015-07-07 | Sentons Inc. | Touch input surface speaker |
US9524063B2 (en) | 2012-07-18 | 2016-12-20 | Sentons Inc. | Detection of a number of touch contacts of a multi-touch input |
CN103576995A (en) * | 2012-07-31 | 2014-02-12 | 电子触控产品解决方案公司 | Touch sensitive display with acoustic isolation |
US9277349B2 (en) | 2013-06-12 | 2016-03-01 | Blackberry Limited | Method of processing an incoming communication signal at a mobile communication device |
US20150029112A1 (en) * | 2013-07-26 | 2015-01-29 | Nxp B.V. | Touch sensor |
US9182853B2 (en) | 2013-08-27 | 2015-11-10 | Blackberry Limited | Function selection by detecting resonant frequencies |
US9588552B2 (en) | 2013-09-11 | 2017-03-07 | Sentons Inc. | Attaching electrical components using non-conductive adhesive |
US9459715B1 (en) | 2013-09-20 | 2016-10-04 | Sentons Inc. | Using spectral control in detecting touch input |
US9880671B2 (en) | 2013-10-08 | 2018-01-30 | Sentons Inc. | Damping vibrational wave reflections |
EP3065043A1 (en) * | 2015-03-02 | 2016-09-07 | Nxp B.V. | Mobile device |
US10048811B2 (en) | 2015-09-18 | 2018-08-14 | Sentons Inc. | Detecting touch input provided by signal transmitting stylus |
US10908741B2 (en) | 2016-11-10 | 2021-02-02 | Sentons Inc. | Touch input detection along device sidewall |
US10296144B2 (en) | 2016-12-12 | 2019-05-21 | Sentons Inc. | Touch input detection with shared receivers |
WO2018140939A1 (en) * | 2017-01-30 | 2018-08-02 | The Charles Stark Draper Laboratory, Inc. | Electro-holographic light field generators and displays |
US10126877B1 (en) | 2017-02-01 | 2018-11-13 | Sentons Inc. | Update of reference data for touch input detection |
US10585522B2 (en) | 2017-02-27 | 2020-03-10 | Sentons Inc. | Detection of non-touch inputs using a signature |
US11009411B2 (en) | 2017-08-14 | 2021-05-18 | Sentons Inc. | Increasing sensitivity of a sensor using an encoded signal |
US11580829B2 (en) | 2017-08-14 | 2023-02-14 | Sentons Inc. | Dynamic feedback for haptics |
CN109753191B (en) * | 2017-11-03 | 2022-07-26 | 迪尔阿扣基金两合公司 | Acoustic touch system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3673327A (en) * | 1970-11-02 | 1972-06-27 | Atomic Energy Commission | Touch actuable data input panel assembly |
US4644100A (en) * | 1985-03-22 | 1987-02-17 | Zenith Electronics Corporation | Surface acoustic wave touch panel system |
US4677336A (en) * | 1985-02-04 | 1987-06-30 | Hitachi, Ltd. | Piezoelectric transducer and process for its production |
US4746914A (en) * | 1985-02-05 | 1988-05-24 | Zenith Electronics Corporation | Cathode ray tube for use in a touch panel display system |
US5177327A (en) * | 1990-11-16 | 1993-01-05 | Exzec, Inc. | Acoustic touch position sensor using shear wave propagation |
US6091406A (en) * | 1996-12-25 | 2000-07-18 | Elo Touchsystems, Inc. | Grating transducer for acoustic touchscreens |
US6225985B1 (en) * | 1999-03-26 | 2001-05-01 | Elo Touchsystems, Inc. | Acoustic touchscreen constructed directly on a cathode ray tube |
US6392167B1 (en) * | 1998-05-07 | 2002-05-21 | Ricoh Company, Ltd. | Acoustic touch position sensing system with large touch sensing surface |
US20020104691A1 (en) * | 2000-10-20 | 2002-08-08 | Joel Kent | Acoustic touch sensor with laminated substrate |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002041232A (en) * | 2000-07-21 | 2002-02-08 | Daicel Chem Ind Ltd | Acoustic touch sensing device |
-
2003
- 2003-06-24 US US10/603,514 patent/US7119800B2/en active Active
-
2004
- 2004-05-26 JP JP2006517162A patent/JP4806632B2/en not_active Expired - Fee Related
- 2004-05-26 CN CNB2004800237647A patent/CN100426205C/en not_active Expired - Fee Related
- 2004-05-26 CA CA002529715A patent/CA2529715A1/en not_active Abandoned
- 2004-05-26 EP EP04753691A patent/EP1639442B1/en not_active Expired - Fee Related
- 2004-05-26 AU AU2004255825A patent/AU2004255825A1/en not_active Abandoned
- 2004-05-26 US US10/561,873 patent/US20070268276A1/en not_active Abandoned
- 2004-05-26 MX MXPA05014027A patent/MXPA05014027A/en not_active Application Discontinuation
- 2004-05-26 WO PCT/US2004/016908 patent/WO2005006242A2/en active Application Filing
- 2004-05-26 EP EP11169703A patent/EP2378401A1/en not_active Withdrawn
- 2004-06-09 TW TW093116584A patent/TW200516501A/en unknown
-
2006
- 2006-10-06 US US11/544,188 patent/US7456825B2/en not_active Expired - Fee Related
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3673327A (en) * | 1970-11-02 | 1972-06-27 | Atomic Energy Commission | Touch actuable data input panel assembly |
US4677336A (en) * | 1985-02-04 | 1987-06-30 | Hitachi, Ltd. | Piezoelectric transducer and process for its production |
US4746914A (en) * | 1985-02-05 | 1988-05-24 | Zenith Electronics Corporation | Cathode ray tube for use in a touch panel display system |
US4644100A (en) * | 1985-03-22 | 1987-02-17 | Zenith Electronics Corporation | Surface acoustic wave touch panel system |
US5177327A (en) * | 1990-11-16 | 1993-01-05 | Exzec, Inc. | Acoustic touch position sensor using shear wave propagation |
US6091406A (en) * | 1996-12-25 | 2000-07-18 | Elo Touchsystems, Inc. | Grating transducer for acoustic touchscreens |
US6392167B1 (en) * | 1998-05-07 | 2002-05-21 | Ricoh Company, Ltd. | Acoustic touch position sensing system with large touch sensing surface |
US6225985B1 (en) * | 1999-03-26 | 2001-05-01 | Elo Touchsystems, Inc. | Acoustic touchscreen constructed directly on a cathode ray tube |
US20020104691A1 (en) * | 2000-10-20 | 2002-08-08 | Joel Kent | Acoustic touch sensor with laminated substrate |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8228306B2 (en) | 2008-07-23 | 2012-07-24 | Flextronics Ap, Llc | Integration design for capacitive touch panels and liquid crystal displays |
US9128568B2 (en) | 2008-07-30 | 2015-09-08 | New Vision Display (Shenzhen) Co., Limited | Capacitive touch panel with FPC connector electrically coupled to conductive traces of face-to-face ITO pattern structure in single plane |
US8209861B2 (en) | 2008-12-05 | 2012-07-03 | Flextronics Ap, Llc | Method for manufacturing a touch screen sensor assembly |
US8507800B2 (en) | 2008-12-05 | 2013-08-13 | Multek Display (Hong Kong) Limited | Capacitive touch panel having dual resistive layer |
US8274486B2 (en) | 2008-12-22 | 2012-09-25 | Flextronics Ap, Llc | Diamond pattern on a single layer |
WO2011126674A2 (en) * | 2010-03-30 | 2011-10-13 | Flextronics Ap, Llc | Simplified mechanical design for an acoustic touch screen |
WO2011126674A3 (en) * | 2010-03-30 | 2011-12-22 | Flextronics Ap, Llc | Simplified mechanical design for an acoustic touch screen |
KR101365966B1 (en) | 2010-03-30 | 2014-03-12 | 플렉스트로닉스 에이피, 엘엘씨 | Simplified mechanical design for an acoustic touch screen |
US9285929B2 (en) | 2010-03-30 | 2016-03-15 | New Vision Display (Shenzhen) Co., Limited | Touchscreen system with simplified mechanical touchscreen design using capacitance and acoustic sensing technologies, and method therefor |
US8525955B2 (en) | 2012-01-31 | 2013-09-03 | Multek Display (Hong Kong) Limited | Heater for liquid crystal display |
Also Published As
Publication number | Publication date |
---|---|
WO2005006242A3 (en) | 2005-03-24 |
CN100426205C (en) | 2008-10-15 |
EP1639442B1 (en) | 2012-10-17 |
JP4806632B2 (en) | 2011-11-02 |
CA2529715A1 (en) | 2005-01-20 |
CN1839366A (en) | 2006-09-27 |
TW200516501A (en) | 2005-05-16 |
AU2004255825A1 (en) | 2005-01-20 |
US20070024599A1 (en) | 2007-02-01 |
MXPA05014027A (en) | 2006-03-09 |
EP2378401A1 (en) | 2011-10-19 |
US20040263490A1 (en) | 2004-12-30 |
US7456825B2 (en) | 2008-11-25 |
WO2005006242A2 (en) | 2005-01-20 |
US7119800B2 (en) | 2006-10-10 |
JP2007535010A (en) | 2007-11-29 |
EP1639442A2 (en) | 2006-03-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1639442B1 (en) | Acoustic touch sensor with low-profile diffractive grating transducer assembly | |
US8941624B2 (en) | Acoustic touch sensor utilizing edge waves | |
JP4989461B2 (en) | Elastic wave touch screen | |
US7000474B2 (en) | Acoustic device using higher order harmonic piezoelectric element | |
EP2385444B1 (en) | Acoustic touch sensor | |
US5739479A (en) | Gentle-bevel flat acoustic wave touch sensor | |
JP2004515835A (en) | Elastic wave touch screen with reflector array with waveguide | |
JP2007065798A (en) | Touch panel device | |
JP4562578B2 (en) | Touch panel and touch panel type coordinate input method | |
JP3010669B2 (en) | Touch input panel | |
JP3749608B2 (en) | Touch coordinate input device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: TYCO ELECTRONICS CORPORATION, PENNSYLVANIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ELO TOUCHSYSTEMS, INC.;REEL/FRAME:017105/0022 Effective date: 20051221 |
|
AS | Assignment |
Owner name: TYCO ELECTRONICS CORPORATION, PENNSYLVANIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KENT, JOEL C.;ADLER, ROBERT;COOPER, CHARLES D.;AND OTHERS;REEL/FRAME:017138/0144;SIGNING DATES FROM 20060127 TO 20060130 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |