WO2012063167A1 - Illumination device with switchable projection patterns - Google Patents

Illumination device with switchable projection patterns Download PDF

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Publication number
WO2012063167A1
WO2012063167A1 PCT/IB2011/054886 IB2011054886W WO2012063167A1 WO 2012063167 A1 WO2012063167 A1 WO 2012063167A1 IB 2011054886 W IB2011054886 W IB 2011054886W WO 2012063167 A1 WO2012063167 A1 WO 2012063167A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
illumination device
mask
pattern
generating unit
Prior art date
Application number
PCT/IB2011/054886
Other languages
French (fr)
Inventor
Michel Cornelis Josephus Marie Vissenberg
Anthonie Hendrik Bergman
Ramon Pascal Van Gorkom
Original Assignee
Koninklijke Philips Electronics N.V.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2012063167A1 publication Critical patent/WO2012063167A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/40—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters with provision for controlling spectral properties, e.g. colour, or intensity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2131/00—Use or application of lighting devices or systems not provided for in codes F21W2102/00-F21W2121/00
    • F21W2131/20—Lighting for medical use
    • F21W2131/205—Lighting for medical use for operating theatres
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2131/00—Use or application of lighting devices or systems not provided for in codes F21W2102/00-F21W2121/00
    • F21W2131/40—Lighting for industrial, commercial, recreational or military use
    • F21W2131/406—Lighting for industrial, commercial, recreational or military use for theatres, stages or film studios
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention generally relates to the field of illumination devices.
  • the present invention relates to illumination devices providing lighting patterns.
  • Illumination devices providing patterned projections are nowadays used in a decorative purpose for ambient lighting.
  • Such illumination devices may for instance comprise a light emitting diode (LED) and a cover arranged for projecting a lighting pattern on a surface, e.g. a wall or a lamp shade.
  • LEDs are high-brightness point-like light sources and may advantageously be employed to form fairly compact lamps projecting special lighting patterns.
  • illumination from such lamps is not suitable for general (or functional) lighting, wherein a more uniform lighting is desirable e.g. for reading or working.
  • US 2003/0035092 discloses a light pattern projection system wherein a transmissive-type LCD matrix display is provided as patterning means.
  • a dynamic pattern can be provided by controlling pixels in the LCD display to be transmissive or non-transmissive for light.
  • a disadvantage with such a technique is that it is rather complex and also costly.
  • An object of the present invention is to provide an improved alternative to the above mentioned technique and prior art.
  • an illumination device comprising a first light generating unit arranged to provide a first lighting pattern and a second light generating unit arranged to provide a second lighting pattern.
  • the second lighting pattern is complementary and at least partly superposed to the first lighting pattern.
  • a light intensity of at least one of the first light generating unit and the second light generating unit is adjustable relative to the light intensity of the other light generating unit.
  • a method of operating an illumination device is provided.
  • a first lighting pattern and a second lighting pattern being complementary and at least partly superposed to the first lighting pattern are provided. Further, a light intensity of at least one of the first lighting pattern and the second lighting pattern is adjusted.
  • the present invention is based on the idea of providing at least two lighting patterns being complementary to each other, which means that one of the lighting patterns is a negative image of the other. Further, the lighting patterns are at least partly superposed, i.e. overlapping each other at a surface they may be projected on. When the respective light intensities of the two light generating units are at different levels, the superposition of the first lighting pattern and the second lighting pattern will result in a single patterned projection at the surface, thereby providing a pattern mode suitable for e.g. ambient lighting. When the light intensities of the two light generating units are at the same level (or nearly the same), the superposition of the first lighting pattern and the second lighting pattern results in a more uniform lighting, i.e. without (or at least almost no) pattern on the surface since the first lighting pattern completes and fills out the second lighting pattern and vice versa. In this latter case, the illumination device provides a functional mode suitable for e.g. general lighting or task lighting.
  • the present invention is advantageous in that it provides an illumination device with a switchable patterning function.
  • the illumination device can provide at least two application modes; namely the pattern mode and the functional mode (as defined above), by adjusting the light intensity of at least one of the light generating units.
  • the light intensity may be adjusted e.g. by switching one of the light generating units on or off, thereby switching between functional lighting (with both units turned on) and ambient lighting (with one of the units turned off).
  • the illumination device may further comprise a control unit configured to control the light intensity of at least one of the first light generating unit and the second light generating unit.
  • the present embodiment is advantageous in that it allows at least one of the light generating units to be controlled in a desired manner.
  • the control unit may allow the patterned projection to be controlled in predetermined time cycles, in response to a remote signal or in any other desired way.
  • At least one of the first light generating unit and the second light generating unit may be dimmable, which is advantageous in that the projected pattern may variably appear more or less visible (i.e. the contrast of the patterned projection may be adjusted) and that the total illumination from the illumination device may be of different light intensities. Further, if both light generating units are dimmable, lighting in the functional mode also may be dimmable, and the ratio between the light intensities of the first light generating unit and the second light generating unit may be adjusted such that either the first lighting pattern or the second lighting pattern may dominate the patterned projection.
  • the present embodiment is advantageous in that the illumination device provides a plurality of application modes.
  • the first light generating unit may comprise a first light source associated with a first pattern projecting optics (or first patterning means) for providing the first lighting pattern.
  • the second light generating unit may comprise a second light source associated with a second pattern projecting optics (or second patterning means) for providing the second lighting pattern.
  • the illumination device may further comprise at least one mask equipped with portions allowing transmission of light for providing the first pattern projecting optics and the second pattern projecting optics.
  • a lighting pattern may be provided corresponding to the pattern formed by the arrangement of the portions allowing transmission of light.
  • the mask may further comprise portions blocking transmission of light and/or portions differing e.g. in color or luminous transmittance.
  • the mask may be of any size or geometrical shape suitable for the purpose of the illumination device (and in particular for incorporation within the illumination device). The present embodiment is advantageous in that the manufacture of the illumination device is facilitated and consequently of low cost.
  • the first light source and the second light source may be symmetrically arranged with respect to the mask.
  • the first lighting pattern provided by the first light source and the second lighting pattern provided by the second light source may coincide.
  • the first and the second lighting patterns may then fully compensate each other (i.e. be cancelled out) if the light sources emit light at the same intensity.
  • the mask may separate a first region, in which the first light source may be arranged, from a second region in which the second light source may be arranged. Further, at least one of a first side of the mask facing the first light source and a second side of the mask facing the second light source may be at least partly reflective (i.e. a surface material of the first or second side may be at least partly reflective).
  • a lighting pattern is formed by light reflection against the reflective side (or reflective portions at this side) of the mask and another lighting pattern is formed by light transmission through the light transmitting portions of the mask.
  • only one lighting pattern may be formed by light transmission through the light transmitting portions of the mask.
  • the lighting pattern formed by light transmission of light emitted by the light source facing the non-reflective side of the mask and the lighting pattern formed by reflection, against the reflective side of the mask, of light emitted by the light source facing the reflective side of the mask are complementary.
  • the present embodiment is advantageous in that it provides a compact illumination device providing complementary lighting patterns.
  • the respective intensities of the first light source and second light source may then be controlled (adjusted) in order to provide various types of lighting (with or without pattern, or with an enhanced or diminished contrast in the resulting pattern).
  • the present embodiment is also advantageous in that the lighting patterns may match both in the near field and the far field, i.e. that the lighting patterns may match at different distances from the illumination device, since the first and second lighting patterns originate from the same mask.
  • the illumination device according to the present embodiment may be suitable for use together with lamp shades as well as in a room with walls located at different distances from the illumination device.
  • both the first side and the second side of the mask may be at least partly reflective.
  • a larger fraction of the light emitted by the light sources is output from the illumination device.
  • all, or at least a great part of the light emitted from the light sources is used to provide functional lighting and accordingly, the efficiency of the illumination device is improved.
  • the use of a mask having two reflective sides is advantageous in that both the first lighting pattern and the second lighting pattern can be switched off (i.e. compensated by each other) while both light sources emit light at the same power level, thereby resulting in an uniform lighting projection area.
  • the light sources may be symmetrically positioned relative to the mask, which is advantageous in that a total (or full) cancellation of the first lighting pattern and the second lighting pattern can be provided when the illumination device is in the functional mode (thereby resulting in an uniform lighting in the projection area resulting from the superposition of the first and the second lighting patterns).
  • the reflected image (or lighting pattern) provided by reflection of light emitted from the first light source for instance a light source arranged at a left hand side of the mask
  • the transmitted image or lighting pattern
  • the illumination device may further comprise a plurality of masks symmetrically arranged in respect of each other and a plurality of light sources symmetrically distributed between the masks.
  • the illumination device may further comprise a second mask and a third mask arranged such that the three masks are positioned at an angle of about 120° from each other.
  • the present embodiment is advantageous in that it increases the number of possibilities in creating patterned projections and thereby provides a greater variation in lighting modes or applications.
  • a third region may be defined in which a third light source may be positioned. For example, if one light source is switched on and the two others are switched off, a certain pattern may appear, and if two light sources are switched on and the third light source is switched off, another pattern may appear.
  • the portions of the mask allowing transmission of light may form a periodic pattern.
  • the first light source and the second light source may be positioned at the same side of the mask at a distance from each other corresponding to about a half period in the periodic pattern.
  • the term "periodic pattern" may be construed to be a linearly varying structure of alternating complementary patterns (for example, alternating transmitting and non-transmitting stripes of constant width). With such an arrangement, the lighting patterns provided by the two light sources may be complementary.
  • the light sources can be placed close to each other, which may be well suited for use in e.g. omnidirectional light bulbs.
  • the lighting patterns may match relatively well at different distances from the illumination device, in particular for the far field.
  • the complementary lighting patterns may match very well (i.e. overlap) at distances larger than the distance (spacing) between the light sources, i.e. especially at distances greater than about ten times the distance between the light sources.
  • the illumination device may comprise a first mask equipped with portions allowing transmission of light for providing the first pattern projecting optics (or first patterning means) and a second mask equipped with portions allowing transmission of light for providing the second pattern projecting optics (or second patterning means).
  • the first mask may be separate from the second mask, i.e. the first mask and the second mask may be two separate entities. In the illumination device, this means that the first mask is positioned apart from the second mask.
  • control unit may be configured to individually control any one of the first light generating unit and the second light generating unit such that they can be sequentially switched on and off. Accordingly, visual effects, e.g. a moving pattern, may be provided.
  • the light sources may be light emitting diodes (LEDs) and/or side-firing light emitting diodes.
  • LEDs are (small) pointlike light sources
  • an illumination device according to the present embodiment may be made compact and the matching of the two lighting patterns may be improved. Further, the efficiency of the illumination device may be improved since LEDs are high efficient light sources.
  • side-firing LEDs is advantageous in that less light is aimed in directions others than towards the pattern projecting optics, thereby further enhancing efficiency since all, or at least a great part, of the light from the LED is put out from the illumination device.
  • a light source may be provided with a shield for hindering light from the light source to be emitted in other directions than towards its associated pattern projecting optics.
  • the present embodiment is advantageous in that the light emitted by a light source in other directions than towards its associated pattern projecting optics is prevented from being aimed at (or directed to) the patterned projection.
  • the light emitted by a light source in other directions than towards its associated patterning means is hindered from potentially deteriorating the projected pattern.
  • At least one of the light sources may be provided with a scattering exit diffuser for reducing the brightness of the light source and to smear out projection errors due to the finite mask thickness and alignment errors.
  • a scattering exit diffuser is particularly advantageous for illumination devices comprising a mask having a periodic pattern and two light sources being positioned at the same side of the mask, or for illumination devices comprising several masks positioned at a specific angle from each other and light sources being positioned between the masks.
  • the use of a scattering exit diffuser is then advantageous in that it is more comfortable for human eyes to look at the light source since the brightness of the light source is reduced.
  • the mask may be provided with portions provided with a dichroic filter.
  • the dichroic filter transmits a part of a color spectrum and reflects the complementary part of the color spectrum.
  • the present embodiment is advantageous in that the illumination device can output light of different colors.
  • the pattern projecting optics may be replaceable.
  • the pattern projecting optics may be changed when desired, e.g. if a different pattern is desired or if the pattern projection optics has been damaged.
  • Figure la shows an illumination device in a pattern mode according to an embodiment of the present invention
  • Figure lb shows an illumination device in a functional mode according to an embodiment of the present invention
  • Figure 2 shows an illumination device provided with a mask with at least one reflective side according to an embodiment of the invention
  • Figure 3 shows an illumination device with three masks according to an embodiment of the invention
  • Figure 4 shows an illumination device with four masks according to an embodiment of the invention
  • Figure 5 shows examples of patterned projections provided by an illumination device according to the embodiment shown in Figure 4;
  • Figure 6 shows an illumination device wherein two light sources are positioned at the same side of a mask according to an embodiment of the invention
  • Figure 7 shows an illumination device comprising a light bulb in accordance with an embodiment of the present invention
  • Figure 8 shows examples of different periodic patterns for use in an illumination device according to the embodiment shown in Figures 6 or 7;
  • Figure 9 shows an illumination device provided with a plurality of light sources and a control unit for providing a moving pattern according to an embodiment of the invention.
  • Figure la shows an illumination device 1 comprising a first light generating unit 110a for providing a first lighting pattern and a second light generating unit 110b for providing a second lighting pattern being complementary and at least partly superposed to the first lighting pattern.
  • the first light generating unit 110a further comprises a first light source 101a arranged to illuminate a first pattern projecting optics 102a such that the first lighting pattern is provided.
  • the second light generating unit 110b further comprises a second light source 10 lb arranged to illuminate a second pattern projecting optics 102b such that the second lighting pattern is provided.
  • the first pattern projecting optics 102a and the second pattern projecting optics 102b are two separate entities.
  • the first pattern projecting optics is referred to as the first mask 102a and the second pattern projecting optics is referred to as the second mask 102b.
  • the first mask 102a and the second mask 102b are equipped with portions 104a, 104b, respectively, allowing transmission of light and in particular, light emitted from their associated light sources 101a, 101b, respectively.
  • the first mask 102a and the second mask 102b may further be equipped with portions 105a, 105b, respectively, blocking transmission of light, or at least differing in light transmittance from the
  • portions 104a, 104b allowing transmission of light.
  • the first lighting pattern and the second lighting pattern provided by the first pattern projecting optics and the second pattern projecting optics, respectively, are complementary such that they are a negative image of each other.
  • the light sources 101a, 101b and the masks 102a, 102b are arranged such that the first lighting pattern and the second lighting pattern are at least partly superposed.
  • the portions 104a, 105a of the first mask 102a form a specific pattern which corresponds to the first lighting pattern.
  • the portions 104b, 105b of the second mask 102b form a specific pattern which corresponds to the second lighting pattern.
  • portions 104b, 105b of the second mask 102b provide a special lighting pattern being complementary to the lighting pattern formed by the portions 104a, 105 a of the first mask 102a.
  • the portions 104b of the second mask 102b allowing transmission of light may be arranged to correspond to the portions 105a of the first mask 102a blocking transmission of light
  • the portions 105b of the second mask 102b blocking transmission of light may be arranged to correspond to the portions 104a of the first mask 102a allowing transmission of light.
  • the first lighting pattern and the second lighting pattern may be projected such that they are at least almost entirely superposed (i.e. overlapping each other).
  • the light intensity of at least one of the first light generating unit 110a and the second light generating 110b unit is adjustable relative to the light intensity of the other light generating unit.
  • the light intensity of at least one of the light sources 101a, 101b may be adjustable.
  • the two light sources 101a, 101b may be operated at different light intensity levels, whereby a patterned projection 120a is provided by the superposition of the first lighting pattern and the second lighting pattern, as illustrated in Figure la.
  • the two light sources 101a, 101b may be operated at the same light intensity level.
  • a more uniform distribution of light as represented by the homogeneously illuminated area 120b in Figure lb, will be provided by the superposition of the first lighting pattern and the second lighting pattern.
  • Figure 2 shows an illumination device 2 comprising a mask 200, a first light source 201a and a second light source 201b.
  • the mask 200 separates a first region 210a, in which the first light source 201a is arranged, from a second region 210b in which the second light source 201b is arranged.
  • the first light source 201a and the second light source 201b may advantageously be symmetrically arranged at different sides of the mask 200, i.e. at the same distance from the mask 200 and facing opposite sides of the mask.
  • a deviation from the symmetry of the light sources (201a, 201b) may preferably be less than the size of the light sources.
  • the illumination device may in that case provide (at least almost) a total cancelation of the patterned projection when being in the functional mode.
  • the mask 200 may be provided with portions 204 allowing transmission of light and with portions 205 blocking transmission of light.
  • at least a first side 220a of the mask 200 may be (at least partly) reflective.
  • the first lighting pattern and the second lighting pattern may not fully compensate each other.
  • the illumination device provides for a number of light pattern effects.
  • the relative intensities of the first light source and the second light source can be varied
  • the light sources are advantageously arranged in a symmetrical manner relative to the mask (thereby obtaining a uniformly illuminated projection area by the superposition of the first lighting pattern and the second lighting pattern). Further, it will be appreciated that, for a compensation of the first and second lighting patterns with the first and the second light sources emitting light at the same power level, both sides of the mask are advantageously equipped with a highly reflective material.
  • the mask 200 may e.g. be provided with portions of a dichroic filter transmitting a part of the color spectrum of the light emitted from the first light source (201a) and reflects a complementary part of the color spectrum of the light emitted from the second light source (201b).
  • first light source 201a illuminates the first side 220a of the mask 200
  • light beams 202 originating from the first light source 201a will be reflected against the portions 205 being reflective and blocking transmission of light, thereby providing a first lighting pattern.
  • second light source 201b illuminates the second side 220b of the mask 200
  • light beams originating from the second light source 201b will pass through the portions 204 of the mask 200 allowing transmission of light, thereby providing a second lighting pattern which accordingly is complementary and superposed to the first lighting pattern.
  • a third lighting pattern will then be provided by the light beams 203 originating from the first light source 201a emitted through the portions 204 allowing transmission of light.
  • the second side 220b of the mask 200 may be reflective, whereby a fourth lighting pattern may be provided by the light beams originating from the second light source 201b and being reflected against the portions 205 of the mask 200 being reflective and blocking transmission of light. Accordingly, the fourth lighting pattern is complementary and superposed to the third lighting pattern.
  • the light intensity of at least one of the first light source 201a and the second light source 201b is adjustable, whereby a switchable patterning function is provided.
  • the illumination device 2 can provide a pattern mode and a functional mode.
  • the light sources 201a, 201b may be dimmable.
  • Figure 3 shows an illumination device comprising a first mask 310, a second mask 320 and a third mask 330 arranged such that the three masks are positioned at an angle of about 120° from each other.
  • a first region 306 defined by the first mask 310 and the second mask 320 is formed.
  • a second region 307 defined by the first mask 310 and the third mask 330, and a third region 308 defined by the second mask 320 and the third mask 330 are formed.
  • about 120° means that the three masks not necessarily have to be positioned at an angle of exactly 120° from each other, but at an angle of approximately 120° ⁇ 20° from each other.
  • the illumination device further comprises a first light source 301a arranged in the first region 306, a second light source 301b arranged in the second region 307, and a third light source 301c arranged in the third region 308.
  • the three light sources 301a, 301b, 301c may be arranged symmetrically between the three masks 310, 320, 330, i.e. each one at the same distance from a mask and at the same distance from a point at which the three masks may intersect.
  • the masks may be equivalent to the mask described with reference to Figures la, lb and 2, i.e. equipped with portions allowing transmission of light and portions blocking or reflecting light.
  • the illumination device may comprise four masks 410, 420, 430, 440, as illustrated in Figure 4.
  • the four masks are arranged such that they are positioned at an angle of about 90° from each other, thereby providing four regions.
  • the term "about 90°" means
  • At least one side of at least one of the four masks 410, 420, 430, 440 may be reflective.
  • all sides of the masks are reflective.
  • the illumination device may further comprise four light sources 401a, 401b, 401c, 401d, each one arranged in each one of the four regions, in a similar manner as that described with reference to Figure 3.
  • the four light sources are symmetrically arranged between the four masks 410, 420, 430, 440.
  • the light intensity may adjustable for at least one, but preferably all light sources, thereby providing an illumination device with a switchable patterning function.
  • Figure 5 shows examples of patterned projections provided by the illumination device described with reference to Figure 4, i.e. with four masks and four light sources.
  • the examples are presented in a table with four columns 505-508, and four rows 501-504.
  • columns 505, 506, 507, 508 patterned projections in four directions orthogonal to each other are shown.
  • a first row 501 shows patterned projections when one light source is on and the three others are off;
  • a second row 502 shows patterned projections when two light sources have substantially the same light intensity and the two others are off;
  • a third row 503 shows patterned projections when three light sources have substantially the same light intensity and one is off;
  • a fourth row 504 shows patterned projections when all light source have substantially the same light intensity.
  • Figure 5 illustrates the possibility of providing a large number of patterned projections with an illumination device according to an embodiment of the present invention.
  • the illumination device may comprise six, eight or any other suitable number of masks and corresponding number of light sources.
  • Figure 6 shows an illumination device comprising a first light source 601a and a second light source 601b positioned at the same side of a mask 600.
  • the mask 600 is equipped with portions 604 allowing transmission of light. The arrangement of these portions 604 forms a periodic pattern.
  • the mask 600 may further be equipped with portions 605 for blocking transmission of light.
  • the two light sources 601a, 601b are positioned at a distance from each other corresponding to about a half period in the periodic pattern.
  • the term "about a half means that the light sources 601a, 601b do not necessarily need to be positioned exactly at a half period of the periodic pattern from each other. It will be appreciated that some displacement may not affect the functioning of the illumination device.
  • the light sources 601a, 601b may also be positioned at substantially the same distance from the mask 600.
  • the sources are advantageously arranged at exactly half the period spacing from each other.
  • the displacement is preferably less than the source size (which is preferably point-like).
  • the periodic pattern may comprise an arrangement 801 of alternating transmitting and non-transmitting stripes of constant width or a check arrangement (or check board) 802 of alternating transmitting and non-transmitting checks.
  • the periodic pattern may be more freely designed, such as an arrangement 803 of ellipses on stripes, an arrangement 804 of crosses on stripes, an arrangement 805 of hexagons or an arrangement 806 of waves or any other arrangements providing periodic patterns.
  • the present embodiment of the invention may e.g. be used in omnidirectional light bulbs 700 as shown in Figure 7. The mask may then be placed inside the light bulb.
  • any one of the illumination devices described herein may comprise an envelope in which the mask/masks and the light sources are encapsulated, thereby forming a light bulb.
  • the illumination device may comprise a control unit 103 configured to control the light intensity of at least one of the first light generating unit 110a and the second light generating unit 110b.
  • the control unit 103 may e.g. be configured to receive a remote signal for adjusting the light intensity and/or to control the light generating units 110a, 110b.
  • the control unit 103 may be configured to sequentially switch on and off the light generating units to provide a visual effect such as a moving pattern.
  • the illumination device may comprise at least one additional light generating unit for providing at least one additional lighting pattern corresponding to, and slightly displaced to e.g. the first lighting pattern (or the second lighting pattern).
  • the control unit 103 may then be configured to sequentially switch the first light generating unit 110a (or the second light generating unit 110b) and the additional light generating unit on and off, whereby a moving pattern may be provided.
  • Figure 9 shows an example of an illumination device provided with a control unit 903.
  • the illumination device comprises a mask 900 being reflective at one or both sides 920a, 920b, and equipped with portions 904 allowing transmission of light and portions 905 blocking transmission of light.
  • a first group 901a of light source is arranged at one side 920a of the mask 900.
  • the first group 901a comprises at least two light sources 901a'.
  • a second group light 901b source is arranged.
  • the second group 901b comprises at least one light source 901b' and optionally two or more additional light sources 901b'.
  • the control unit 903 may e.g.
  • the light sources 901a', 901b' may be positioned in any desired way, e.g. symmetrically lined up on each side of the mask, as shown in Figure 9. It will be appreciated that a light source denoted 901a' and its corresponding light source denoted 901b' are advantageously arranged in a symmetrical manner, with respect to each other, relative to the mask 900, as illustrated in Figure 9.
  • Embodiments including a control unit and additional light generating units (or additional light sources) for providing moving patterns may be combined with any one of the embodiments described with reference to Figure la, lb, 2-4 and 6-7, e.g. when two or more masks are provided or when all light sources are at the same side of one mask.
  • the illumination device may be provided with additional light sources, not only in the purpose of providing moving patterns, but also for providing stationary, additional patterns which may be displaced from the first lighting pattern and/or the second lighting pattern.
  • the illumination device may then optionally be provided with yet another additional light source for providing a lighting pattern which is complementary and at least partly superposed to the additional lighting pattern.
  • the additional light source may have a different color than the first light source and the second light source for providing a colored lighting pattern.
  • At least one of the light generating units or light sources may be dimmable, wherein the possibilities to further control the patterned projection in respect of e.g.
  • the pattern mode and the functional mode may be combined.
  • the light sources may be of any suitable type, such as conventional incandescent lamps or halogen lamps.
  • the light sources may be LEDs or any other type of point-like light sources.
  • one or more of the light sources may be provided with a scattering exit diffuser for reducing the brightness of the light source and to smear out projection errors due to the finite mask thickness and alignment errors, which may be advantageous especially when using a mask with a periodic pattern and the two light sources being positioned at the same side of the mask, or when using several masks positioned at a specific angle from each other and the light sources being positioned between the masks.
  • the light sources may be side-firing LEDs for aiming the light emitted from the LEDs at their respective associated pattern projection optics.
  • the light sources may, as an alternative or as a complement, be provided with shields 206 such as shown in Figure 2. Further, the shields 206 may be reflective such that a greater part of the light emitted from a light source is directed towards its associated pattern projecting optics.
  • Masks used in the above described embodiments of the invention may be designed in several different ways.
  • the mask/masks may be provided with portions blocking transmission of light, portions being transparent, portions being semi- transparent, portions only allowing transmission of light of a certain wavelength range (thereby providing a certain color, e.g. by using a dichroic filter) or any other type of portions differing by some means in light transmittance from other portions of the mask/masks.
  • the portions of the mask/masks may be arranged in any desired pattern, e.g. a symmetrical pattern, an asymmetrical pattern or as a more advanced image e.g. originating from a photograph.
  • the mask/masks may be of any desired shape such as e.g. square-shaped or circular. Further, the mask/masks may e.g. be plate-like and of any size suitable for a particular application of the illumination device.
  • the pattern projecting optics may be detachable and replaceable.
  • the present invention may be used in several applications, e.g. in rather small lamps, such as in light bulbs (as shown in Figure 7) or in spotlights, or in larger systems wherein the pattern projecting optics is made larger.
  • the illumination device may be provided with a lamp shade such that patterns are projected at the lamp shade.
  • a method of operating an illumination device may provide a switchable patterning function for an illumination device.
  • the method involves the step of providing a first lighting pattern; providing a second lighting pattern being complementary and at least partly superposed to the first lighting pattern; and adjusting a light intensity of at least one of the first lighting pattern and the second lighting pattern.

Abstract

An illumination device (1) and a method of operating an illumination device are provided. The illumination device comprises a first light generating unit (110a) arranged to provide a first lighting pattern and a second light generating unit (110b) arranged to provide a second lighting pattern. The second lighting pattern is complementary and at least partly superposed to the first lighting pattern. Further, a light intensity of at least one of the first light generating unit and the second light generating unit is adjustable relative to the light intensity of the other light generating unit. The invention is advantageous at least in that it can provide at least two application modes, namely a pattern mode and a functional mode, by adjusting a light intensity of one of the light generating units.

Description

Illumination device with switchable projection patterns
FIELD OF THE INVENTION
The present invention generally relates to the field of illumination devices. In particular, the present invention relates to illumination devices providing lighting patterns.
BACKGROUND OF THE INVENTION
Illumination devices (or lamps) providing patterned projections are nowadays used in a decorative purpose for ambient lighting. Such illumination devices may for instance comprise a light emitting diode (LED) and a cover arranged for projecting a lighting pattern on a surface, e.g. a wall or a lamp shade. LEDs are high-brightness point-like light sources and may advantageously be employed to form fairly compact lamps projecting special lighting patterns. However, illumination from such lamps is not suitable for general (or functional) lighting, wherein a more uniform lighting is desirable e.g. for reading or working.
For providing both ambient lighting and general lighting, two types of lamps may be used, one providing the ambient lighting and one providing the general lighting. However, the drawback is that such a solution is costly and space consuming.
Further, it might be desirable to move or switch the lighting pattern (or image) projected on the surface. For example, US 2003/0035092 discloses a light pattern projection system wherein a transmissive-type LCD matrix display is provided as patterning means. A dynamic pattern can be provided by controlling pixels in the LCD display to be transmissive or non-transmissive for light. A disadvantage with such a technique is that it is rather complex and also costly.
SUMMARY OF THE INVENTION
It is with respect to the above considerations that the present invention has been made. An object of the present invention is to provide an improved alternative to the above mentioned technique and prior art.
More specifically, it is an object of the present invention to provide an illumination device with a switchable patterning function. This and other objects of the present invention are achieved by means of an illumination device having the features defined in the independent claims. Preferable embodiments of the invention are characterized by the dependent claims.
Hence, according to a first aspect of the present invention, an illumination device is provided. The illumination device comprises a first light generating unit arranged to provide a first lighting pattern and a second light generating unit arranged to provide a second lighting pattern. The second lighting pattern is complementary and at least partly superposed to the first lighting pattern. Further, a light intensity of at least one of the first light generating unit and the second light generating unit is adjustable relative to the light intensity of the other light generating unit.
According to a second aspect of the present invention, a method of operating an illumination device is provided. In this method, a first lighting pattern and a second lighting pattern being complementary and at least partly superposed to the first lighting pattern are provided. Further, a light intensity of at least one of the first lighting pattern and the second lighting pattern is adjusted.
The present invention is based on the idea of providing at least two lighting patterns being complementary to each other, which means that one of the lighting patterns is a negative image of the other. Further, the lighting patterns are at least partly superposed, i.e. overlapping each other at a surface they may be projected on. When the respective light intensities of the two light generating units are at different levels, the superposition of the first lighting pattern and the second lighting pattern will result in a single patterned projection at the surface, thereby providing a pattern mode suitable for e.g. ambient lighting. When the light intensities of the two light generating units are at the same level (or nearly the same), the superposition of the first lighting pattern and the second lighting pattern results in a more uniform lighting, i.e. without (or at least almost no) pattern on the surface since the first lighting pattern completes and fills out the second lighting pattern and vice versa. In this latter case, the illumination device provides a functional mode suitable for e.g. general lighting or task lighting.
The present invention is advantageous in that it provides an illumination device with a switchable patterning function. In particular, the illumination device can provide at least two application modes; namely the pattern mode and the functional mode (as defined above), by adjusting the light intensity of at least one of the light generating units. The light intensity may be adjusted e.g. by switching one of the light generating units on or off, thereby switching between functional lighting (with both units turned on) and ambient lighting (with one of the units turned off).
According to an embodiment of the invention, the illumination device may further comprise a control unit configured to control the light intensity of at least one of the first light generating unit and the second light generating unit. The present embodiment is advantageous in that it allows at least one of the light generating units to be controlled in a desired manner. For example, the control unit may allow the patterned projection to be controlled in predetermined time cycles, in response to a remote signal or in any other desired way.
According to an embodiment of the present invention, at least one of the first light generating unit and the second light generating unit may be dimmable, which is advantageous in that the projected pattern may variably appear more or less visible (i.e. the contrast of the patterned projection may be adjusted) and that the total illumination from the illumination device may be of different light intensities. Further, if both light generating units are dimmable, lighting in the functional mode also may be dimmable, and the ratio between the light intensities of the first light generating unit and the second light generating unit may be adjusted such that either the first lighting pattern or the second lighting pattern may dominate the patterned projection. The present embodiment is advantageous in that the illumination device provides a plurality of application modes.
According to an embodiment of the invention, the first light generating unit may comprise a first light source associated with a first pattern projecting optics (or first patterning means) for providing the first lighting pattern. Furthermore, the second light generating unit may comprise a second light source associated with a second pattern projecting optics (or second patterning means) for providing the second lighting pattern. As compared to prior art techniques based on e.g. an LCD matrix display, such an
implementation of the present invention is advantageous in that it is rather less complex.
According to an embodiment of the invention, the illumination device may further comprise at least one mask equipped with portions allowing transmission of light for providing the first pattern projecting optics and the second pattern projecting optics. When the mask is illuminated by a light source, a lighting pattern may be provided corresponding to the pattern formed by the arrangement of the portions allowing transmission of light. The mask may further comprise portions blocking transmission of light and/or portions differing e.g. in color or luminous transmittance. The mask may be of any size or geometrical shape suitable for the purpose of the illumination device (and in particular for incorporation within the illumination device). The present embodiment is advantageous in that the manufacture of the illumination device is facilitated and consequently of low cost.
Advantageously, the first light source and the second light source may be symmetrically arranged with respect to the mask. As a result, the first lighting pattern provided by the first light source and the second lighting pattern provided by the second light source may coincide. The first and the second lighting patterns may then fully compensate each other (i.e. be cancelled out) if the light sources emit light at the same intensity.
According to an embodiment of the invention, the mask may separate a first region, in which the first light source may be arranged, from a second region in which the second light source may be arranged. Further, at least one of a first side of the mask facing the first light source and a second side of the mask facing the second light source may be at least partly reflective (i.e. a surface material of the first or second side may be at least partly reflective). In the present embodiment, for the light source facing the (at least partly) reflective side of the mask, a lighting pattern is formed by light reflection against the reflective side (or reflective portions at this side) of the mask and another lighting pattern is formed by light transmission through the light transmitting portions of the mask. For the light source facing the non-reflective side of the mask, only one lighting pattern may be formed by light transmission through the light transmitting portions of the mask. The lighting pattern formed by light transmission of light emitted by the light source facing the non-reflective side of the mask and the lighting pattern formed by reflection, against the reflective side of the mask, of light emitted by the light source facing the reflective side of the mask are complementary.
The present embodiment is advantageous in that it provides a compact illumination device providing complementary lighting patterns. The respective intensities of the first light source and second light source may then be controlled (adjusted) in order to provide various types of lighting (with or without pattern, or with an enhanced or diminished contrast in the resulting pattern).
The present embodiment is also advantageous in that the lighting patterns may match both in the near field and the far field, i.e. that the lighting patterns may match at different distances from the illumination device, since the first and second lighting patterns originate from the same mask. Hence, the illumination device according to the present embodiment may be suitable for use together with lamp shades as well as in a room with walls located at different distances from the illumination device. According to an embodiment of the invention, both the first side and the second side of the mask may be at least partly reflective. An advantage of the present embodiment is that when the illumination device is in a functional mode, i.e. when the light generating units have the same (or nearly the same) light intensity, less light is absorbed by the mask. In other words, a larger fraction of the light emitted by the light sources is output from the illumination device. Hence, all, or at least a great part of the light emitted from the light sources is used to provide functional lighting and accordingly, the efficiency of the illumination device is improved. In addition, the use of a mask having two reflective sides is advantageous in that both the first lighting pattern and the second lighting pattern can be switched off (i.e. compensated by each other) while both light sources emit light at the same power level, thereby resulting in an uniform lighting projection area.
Further, the light sources may be symmetrically positioned relative to the mask, which is advantageous in that a total (or full) cancellation of the first lighting pattern and the second lighting pattern can be provided when the illumination device is in the functional mode (thereby resulting in an uniform lighting in the projection area resulting from the superposition of the first and the second lighting patterns). Indeed, if the light sources are arranged at symmetric positions with respect to the mask, the reflected image (or lighting pattern) provided by reflection of light emitted from the first light source (for instance a light source arranged at a left hand side of the mask) coincides with the transmitted image (or lighting pattern) provided by transmission of light emitted from the second light source (or a light source arranged at the right hand side of the mask), and vice versa.
According to an embodiment of the invention, the illumination device may further comprise a plurality of masks symmetrically arranged in respect of each other and a plurality of light sources symmetrically distributed between the masks. For example, the illumination device may further comprise a second mask and a third mask arranged such that the three masks are positioned at an angle of about 120° from each other. The present embodiment is advantageous in that it increases the number of possibilities in creating patterned projections and thereby provides a greater variation in lighting modes or applications. In particular, a third region may be defined in which a third light source may be positioned. For example, if one light source is switched on and the two others are switched off, a certain pattern may appear, and if two light sources are switched on and the third light source is switched off, another pattern may appear. When all three light sources have the same light intensity, no (or almost no) pattern is visible and a more uniform distribution of light is provided. According to an embodiment of the invention, the portions of the mask allowing transmission of light may form a periodic pattern. Further, the first light source and the second light source may be positioned at the same side of the mask at a distance from each other corresponding to about a half period in the periodic pattern. The term "periodic pattern" may be construed to be a linearly varying structure of alternating complementary patterns (for example, alternating transmitting and non-transmitting stripes of constant width). With such an arrangement, the lighting patterns provided by the two light sources may be complementary. An advantage of the present embodiment is that the light sources can be placed close to each other, which may be well suited for use in e.g. omnidirectional light bulbs. Moreover, the lighting patterns may match relatively well at different distances from the illumination device, in particular for the far field. In the present embodiment, the complementary lighting patterns may match very well (i.e. overlap) at distances larger than the distance (spacing) between the light sources, i.e. especially at distances greater than about ten times the distance between the light sources.
According to an embodiment of the invention, the illumination device may comprise a first mask equipped with portions allowing transmission of light for providing the first pattern projecting optics (or first patterning means) and a second mask equipped with portions allowing transmission of light for providing the second pattern projecting optics (or second patterning means). Further, the first mask may be separate from the second mask, i.e. the first mask and the second mask may be two separate entities. In the illumination device, this means that the first mask is positioned apart from the second mask.
According to an embodiment of the invention, the control unit may be configured to individually control any one of the first light generating unit and the second light generating unit such that they can be sequentially switched on and off. Accordingly, visual effects, e.g. a moving pattern, may be provided.
According to an embodiment of the invention, the light sources may be light emitting diodes (LEDs) and/or side-firing light emitting diodes. As LEDs are (small) pointlike light sources, an illumination device according to the present embodiment may be made compact and the matching of the two lighting patterns may be improved. Further, the efficiency of the illumination device may be improved since LEDs are high efficient light sources. The use of side-firing LEDs is advantageous in that less light is aimed in directions others than towards the pattern projecting optics, thereby further enhancing efficiency since all, or at least a great part, of the light from the LED is put out from the illumination device. According to an embodiment of the invention, a light source may be provided with a shield for hindering light from the light source to be emitted in other directions than towards its associated pattern projecting optics. The present embodiment is advantageous in that the light emitted by a light source in other directions than towards its associated pattern projecting optics is prevented from being aimed at (or directed to) the patterned projection. Thus, the light emitted by a light source in other directions than towards its associated patterning means is hindered from potentially deteriorating the projected pattern.
According to an embodiment of the invention, at least one of the light sources may be provided with a scattering exit diffuser for reducing the brightness of the light source and to smear out projection errors due to the finite mask thickness and alignment errors. The use of a scattering exit diffuser is particularly advantageous for illumination devices comprising a mask having a periodic pattern and two light sources being positioned at the same side of the mask, or for illumination devices comprising several masks positioned at a specific angle from each other and light sources being positioned between the masks. The use of a scattering exit diffuser is then advantageous in that it is more comfortable for human eyes to look at the light source since the brightness of the light source is reduced.
According to an embodiment of the invention, the mask may be provided with portions provided with a dichroic filter. The dichroic filter transmits a part of a color spectrum and reflects the complementary part of the color spectrum. The present embodiment is advantageous in that the illumination device can output light of different colors.
According to an embodiment of the invention, the pattern projecting optics may be replaceable. Thus, the pattern projecting optics may be changed when desired, e.g. if a different pattern is desired or if the pattern projection optics has been damaged.
Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following. In particular, it will be appreciated that the various embodiments described for the illumination device are all combinable with the method as defined in accordance with the second aspect of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non- limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, in which:
Figure la shows an illumination device in a pattern mode according to an embodiment of the present invention;
Figure lb shows an illumination device in a functional mode according to an embodiment of the present invention;
Figure 2 shows an illumination device provided with a mask with at least one reflective side according to an embodiment of the invention;
Figure 3 shows an illumination device with three masks according to an embodiment of the invention;
Figure 4 shows an illumination device with four masks according to an embodiment of the invention;
Figure 5 shows examples of patterned projections provided by an illumination device according to the embodiment shown in Figure 4;
Figure 6 shows an illumination device wherein two light sources are positioned at the same side of a mask according to an embodiment of the invention;
Figure 7 shows an illumination device comprising a light bulb in accordance with an embodiment of the present invention;
Figure 8 shows examples of different periodic patterns for use in an illumination device according to the embodiment shown in Figures 6 or 7; and
Figure 9 shows an illumination device provided with a plurality of light sources and a control unit for providing a moving pattern according to an embodiment of the invention.
All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.
DETAILED DESCRIPTION OF EMBODIMENTS
With reference to Figures la and lb, there is shown an illumination device in accordance with an embodiment of the present invention.
Figure la shows an illumination device 1 comprising a first light generating unit 110a for providing a first lighting pattern and a second light generating unit 110b for providing a second lighting pattern being complementary and at least partly superposed to the first lighting pattern. The first light generating unit 110a further comprises a first light source 101a arranged to illuminate a first pattern projecting optics 102a such that the first lighting pattern is provided. The second light generating unit 110b further comprises a second light source 10 lb arranged to illuminate a second pattern projecting optics 102b such that the second lighting pattern is provided.
In the embodiment of the invention described here with reference to Figures la and lb, the first pattern projecting optics 102a and the second pattern projecting optics 102b are two separate entities. In the following, the first pattern projecting optics is referred to as the first mask 102a and the second pattern projecting optics is referred to as the second mask 102b. The first mask 102a and the second mask 102b are equipped with portions 104a, 104b, respectively, allowing transmission of light and in particular, light emitted from their associated light sources 101a, 101b, respectively. The first mask 102a and the second mask 102b may further be equipped with portions 105a, 105b, respectively, blocking transmission of light, or at least differing in light transmittance from the
portions 104a, 104b allowing transmission of light.
The first lighting pattern and the second lighting pattern provided by the first pattern projecting optics and the second pattern projecting optics, respectively, are complementary such that they are a negative image of each other. In addition, the light sources 101a, 101b and the masks 102a, 102b are arranged such that the first lighting pattern and the second lighting pattern are at least partly superposed. When illuminated by the first light source 101a, the portions 104a, 105a of the first mask 102a form a specific pattern which corresponds to the first lighting pattern. Similarly, when illuminated by the second light source 101b, the portions 104b, 105b of the second mask 102b form a specific pattern which corresponds to the second lighting pattern. Thus, under illumination, the
portions 104b, 105b of the second mask 102b provide a special lighting pattern being complementary to the lighting pattern formed by the portions 104a, 105 a of the first mask 102a. In particular, the portions 104b of the second mask 102b allowing transmission of light may be arranged to correspond to the portions 105a of the first mask 102a blocking transmission of light, and the portions 105b of the second mask 102b blocking transmission of light may be arranged to correspond to the portions 104a of the first mask 102a allowing transmission of light. Preferably, the first lighting pattern and the second lighting pattern may be projected such that they are at least almost entirely superposed (i.e. overlapping each other).
The light intensity of at least one of the first light generating unit 110a and the second light generating 110b unit is adjustable relative to the light intensity of the other light generating unit. In this particular embodiment, the light intensity of at least one of the light sources 101a, 101b may be adjustable. For providing a pattern mode with the illumination device 1, the two light sources 101a, 101b may be operated at different light intensity levels, whereby a patterned projection 120a is provided by the superposition of the first lighting pattern and the second lighting pattern, as illustrated in Figure la. For providing a functional mode with the illumination device 1, the two light sources 101a, 101b may be operated at the same light intensity level. As a result, a more uniform distribution of light, as represented by the homogeneously illuminated area 120b in Figure lb, will be provided by the superposition of the first lighting pattern and the second lighting pattern.
In the following, another embodiment of the present invention will be described with reference to Figure 2.
Figure 2 shows an illumination device 2 comprising a mask 200, a first light source 201a and a second light source 201b. The mask 200 separates a first region 210a, in which the first light source 201a is arranged, from a second region 210b in which the second light source 201b is arranged. Although the present embodiment is not limited to such an arrangement, the first light source 201a and the second light source 201b may advantageously be symmetrically arranged at different sides of the mask 200, i.e. at the same distance from the mask 200 and facing opposite sides of the mask. In particular, a deviation from the symmetry of the light sources (201a, 201b) may preferably be less than the size of the light sources. The illumination device may in that case provide (at least almost) a total cancelation of the patterned projection when being in the functional mode. The mask 200 may be provided with portions 204 allowing transmission of light and with portions 205 blocking transmission of light. According to the present embodiment, at least a first side 220a of the mask 200 may be (at least partly) reflective.
It will be appreciated that if the light sources are not arranged in a symmetrical manner with respect to the mask, the first lighting pattern and the second lighting pattern may not fully compensate each other. However, such an arrangement is still advantageous in that the illumination device provides for a number of light pattern effects. For this purpose, the relative intensities of the first light source and the second light source can be varied
(controlled). For a total compensation of the lighting patterns, the light sources are advantageously arranged in a symmetrical manner relative to the mask (thereby obtaining a uniformly illuminated projection area by the superposition of the first lighting pattern and the second lighting pattern). Further, it will be appreciated that, for a compensation of the first and second lighting patterns with the first and the second light sources emitting light at the same power level, both sides of the mask are advantageously equipped with a highly reflective material.
Further, the mask 200 may e.g. be provided with portions of a dichroic filter transmitting a part of the color spectrum of the light emitted from the first light source (201a) and reflects a complementary part of the color spectrum of the light emitted from the second light source (201b).
When the first light source 201a illuminates the first side 220a of the mask 200, light beams 202 originating from the first light source 201a will be reflected against the portions 205 being reflective and blocking transmission of light, thereby providing a first lighting pattern. Further, when the second light source 201b illuminates the second side 220b of the mask 200, light beams originating from the second light source 201b will pass through the portions 204 of the mask 200 allowing transmission of light, thereby providing a second lighting pattern which accordingly is complementary and superposed to the first lighting pattern. A third lighting pattern will then be provided by the light beams 203 originating from the first light source 201a emitted through the portions 204 allowing transmission of light.
Advantageously, also the second side 220b of the mask 200 may be reflective, whereby a fourth lighting pattern may be provided by the light beams originating from the second light source 201b and being reflected against the portions 205 of the mask 200 being reflective and blocking transmission of light. Accordingly, the fourth lighting pattern is complementary and superposed to the third lighting pattern.
The light intensity of at least one of the first light source 201a and the second light source 201b is adjustable, whereby a switchable patterning function is provided. Thus, the illumination device 2 according to the present embodiment can provide a pattern mode and a functional mode. In particular, the light sources 201a, 201b may be dimmable.
Still in connection with the embodiment described with reference to Figure 2, , another embodiment of the invention will now be described with reference to Figures 3, 4 and 5.
Figure 3 shows an illumination device comprising a first mask 310, a second mask 320 and a third mask 330 arranged such that the three masks are positioned at an angle of about 120° from each other. As a result, a first region 306 defined by the first mask 310 and the second mask 320 is formed. Similarly, a second region 307 defined by the first mask 310 and the third mask 330, and a third region 308 defined by the second mask 320 and the third mask 330 are formed. Here the term "about 120°" means that the three masks not necessarily have to be positioned at an angle of exactly 120° from each other, but at an angle of approximately 120°±20° from each other. Further, at least one side of any one of the three masks 310, 320, 330 may be reflective. Optionally, both sides of all three masks may be reflective. The illumination device further comprises a first light source 301a arranged in the first region 306, a second light source 301b arranged in the second region 307, and a third light source 301c arranged in the third region 308. Preferably, the three light sources 301a, 301b, 301c may be arranged symmetrically between the three masks 310, 320, 330, i.e. each one at the same distance from a mask and at the same distance from a point at which the three masks may intersect.
In the present embodiment, the masks may be equivalent to the mask described with reference to Figures la, lb and 2, i.e. equipped with portions allowing transmission of light and portions blocking or reflecting light.
In yet another embodiment of the invention, the illumination device may comprise four masks 410, 420, 430, 440, as illustrated in Figure 4. The four masks are arranged such that they are positioned at an angle of about 90° from each other, thereby providing four regions. In the present embodiment, the term "about 90°" means
approximately 90°±10°. Further, at least one side of at least one of the four masks 410, 420, 430, 440 may be reflective. Advantageously, all sides of the masks are reflective.
Optionally, both sides of any or all four masks may be reflective. The illumination device may further comprise four light sources 401a, 401b, 401c, 401d, each one arranged in each one of the four regions, in a similar manner as that described with reference to Figure 3. Advantageously, the four light sources are symmetrically arranged between the four masks 410, 420, 430, 440.
It will be appreciated that in the embodiments described with reference to
Figure 3 and 4, the light intensity may adjustable for at least one, but preferably all light sources, thereby providing an illumination device with a switchable patterning function.
Figure 5 shows examples of patterned projections provided by the illumination device described with reference to Figure 4, i.e. with four masks and four light sources. The examples are presented in a table with four columns 505-508, and four rows 501-504. In columns 505, 506, 507, 508 patterned projections in four directions orthogonal to each other are shown. A first row 501 shows patterned projections when one light source is on and the three others are off; a second row 502 shows patterned projections when two light sources have substantially the same light intensity and the two others are off; a third row 503 shows patterned projections when three light sources have substantially the same light intensity and one is off; and a fourth row 504 shows patterned projections when all light source have substantially the same light intensity. Figure 5 illustrates the possibility of providing a large number of patterned projections with an illumination device according to an embodiment of the present invention.
Although the embodiments described with reference to Figures 3 and 4 comprise three or four sets of light source and mask, respectively, it is also envisaged that the illumination device may comprise six, eight or any other suitable number of masks and corresponding number of light sources.
In the following, another embodiment of the present invention will be described with reference to Figure 6.
Figure 6 shows an illumination device comprising a first light source 601a and a second light source 601b positioned at the same side of a mask 600. The mask 600 is equipped with portions 604 allowing transmission of light. The arrangement of these portions 604 forms a periodic pattern. The mask 600 may further be equipped with portions 605 for blocking transmission of light. The two light sources 601a, 601b are positioned at a distance from each other corresponding to about a half period in the periodic pattern. Here the term "about a half means that the light sources 601a, 601b do not necessarily need to be positioned exactly at a half period of the periodic pattern from each other. It will be appreciated that some displacement may not affect the functioning of the illumination device. Optionally, the light sources 601a, 601b may also be positioned at substantially the same distance from the mask 600.
It will be appreciated that, for a full cancellation of the complementary lighting patterns, the sources are advantageously arranged at exactly half the period spacing from each other. The displacement is preferably less than the source size (which is preferably point-like).
Examples of different periodic patterns which can be employed in an illumination device according to the present embodiment are illustrated in Figure 8. For example, the periodic pattern may comprise an arrangement 801 of alternating transmitting and non-transmitting stripes of constant width or a check arrangement (or check board) 802 of alternating transmitting and non-transmitting checks. Further, the periodic pattern may be more freely designed, such as an arrangement 803 of ellipses on stripes, an arrangement 804 of crosses on stripes, an arrangement 805 of hexagons or an arrangement 806 of waves or any other arrangements providing periodic patterns. The present embodiment of the invention may e.g. be used in omnidirectional light bulbs 700 as shown in Figure 7. The mask may then be placed inside the light bulb.
It will be appreciated that any one of the illumination devices described herein (in particular for embodiments described with reference to Figure la, lb, 2-4 and 9) may comprise an envelope in which the mask/masks and the light sources are encapsulated, thereby forming a light bulb.
In the following, other embodiments of the invention will be described which may be combined with any one of the previously described embodiments. The figures which may be referred to in the following, only show non- limiting examples of how the embodiments may be implemented.
As shown in Figures la, lb, the illumination device may comprise a control unit 103 configured to control the light intensity of at least one of the first light generating unit 110a and the second light generating unit 110b. The control unit 103 may e.g. be configured to receive a remote signal for adjusting the light intensity and/or to control the light generating units 110a, 110b. In particular, the control unit 103 may be configured to sequentially switch on and off the light generating units to provide a visual effect such as a moving pattern.
Furthermore, the illumination device may comprise at least one additional light generating unit for providing at least one additional lighting pattern corresponding to, and slightly displaced to e.g. the first lighting pattern (or the second lighting pattern). The control unit 103 may then be configured to sequentially switch the first light generating unit 110a (or the second light generating unit 110b) and the additional light generating unit on and off, whereby a moving pattern may be provided.
Figure 9 shows an example of an illumination device provided with a control unit 903. The illumination device comprises a mask 900 being reflective at one or both sides 920a, 920b, and equipped with portions 904 allowing transmission of light and portions 905 blocking transmission of light. At one side 920a of the mask 900, a first group 901a of light source is arranged. The first group 901a comprises at least two light sources 901a'. At the other side 920b of the mask 900, a second group light 901b source is arranged. The second group 901b comprises at least one light source 901b' and optionally two or more additional light sources 901b'. The control unit 903 may e.g. be configured to sequentially switch on one of the light sources 901a', 901b' at the time, whereby a moving pattern is provided. The light sources 901a', 901b' may be positioned in any desired way, e.g. symmetrically lined up on each side of the mask, as shown in Figure 9. It will be appreciated that a light source denoted 901a' and its corresponding light source denoted 901b' are advantageously arranged in a symmetrical manner, with respect to each other, relative to the mask 900, as illustrated in Figure 9. Embodiments including a control unit and additional light generating units (or additional light sources) for providing moving patterns may be combined with any one of the embodiments described with reference to Figure la, lb, 2-4 and 6-7, e.g. when two or more masks are provided or when all light sources are at the same side of one mask.
According to other embodiments of the invention, the illumination device may be provided with additional light sources, not only in the purpose of providing moving patterns, but also for providing stationary, additional patterns which may be displaced from the first lighting pattern and/or the second lighting pattern. The illumination device may then optionally be provided with yet another additional light source for providing a lighting pattern which is complementary and at least partly superposed to the additional lighting pattern. For example, the additional light source may have a different color than the first light source and the second light source for providing a colored lighting pattern.
At least one of the light generating units or light sources may be dimmable, wherein the possibilities to further control the patterned projection in respect of e.g.
brightness and contrast increases. For example, it may be possible to let the light intensity of one of the light generating units 110a, 110b be high and the light intensity of the other light generating unit 110a, 110b be decreased to a slightly lower level, such that a patterned projection is provided, but the total illumination from the illumination device is still sufficient for general lighting. Hence, the pattern mode and the functional mode may be combined.
The light sources may be of any suitable type, such as conventional incandescent lamps or halogen lamps. Advantageously, the light sources may be LEDs or any other type of point-like light sources.
Optionally, one or more of the light sources may be provided with a scattering exit diffuser for reducing the brightness of the light source and to smear out projection errors due to the finite mask thickness and alignment errors, which may be advantageous especially when using a mask with a periodic pattern and the two light sources being positioned at the same side of the mask, or when using several masks positioned at a specific angle from each other and the light sources being positioned between the masks.
Moreover, the light sources may be side-firing LEDs for aiming the light emitted from the LEDs at their respective associated pattern projection optics. The light sources may, as an alternative or as a complement, be provided with shields 206 such as shown in Figure 2. Further, the shields 206 may be reflective such that a greater part of the light emitted from a light source is directed towards its associated pattern projecting optics.
Masks used in the above described embodiments of the invention may be designed in several different ways. For example, the mask/masks may be provided with portions blocking transmission of light, portions being transparent, portions being semi- transparent, portions only allowing transmission of light of a certain wavelength range (thereby providing a certain color, e.g. by using a dichroic filter) or any other type of portions differing by some means in light transmittance from other portions of the mask/masks.
Further, the portions of the mask/masks may be arranged in any desired pattern, e.g. a symmetrical pattern, an asymmetrical pattern or as a more advanced image e.g. originating from a photograph.
The mask/masks may be of any desired shape such as e.g. square-shaped or circular. Further, the mask/masks may e.g. be plate-like and of any size suitable for a particular application of the illumination device.
Moreover, the pattern projecting optics (or the mask/masks) may be detachable and replaceable.
The present invention may be used in several applications, e.g. in rather small lamps, such as in light bulbs (as shown in Figure 7) or in spotlights, or in larger systems wherein the pattern projecting optics is made larger. Further, the illumination device may be provided with a lamp shade such that patterns are projected at the lamp shade.
According to the second aspect of the invention, a method of operating an illumination device is provided. In particular, the method may provide a switchable patterning function for an illumination device. The method involves the step of providing a first lighting pattern; providing a second lighting pattern being complementary and at least partly superposed to the first lighting pattern; and adjusting a light intensity of at least one of the first lighting pattern and the second lighting pattern.
While specific embodiments have been described, the skilled person will understand that various modifications and alterations are conceivable within the scope as defined in the appended claims.

Claims

CLAIMS:
1. An illumination device (1) comprising:
a first light generating unit (110a) arranged to provide a first lighting pattern and
a second light generating unit (110b) arranged to provide a second lighting pattern,
wherein the second lighting pattern is complementary and at least partly superposed to the first lighting pattern and wherein a light intensity of at least one of the first light generating unit and the second light generating unit is adjustable relative to the light intensity of the other light generating unit.
2. The illumination device as defined in claim 1, further comprising a control unit (103) configured to control the light intensity of at least one of the first light generating unit and the second light generating unit.
3. The illumination device as defined in claim 1 or 2, wherein at least one of the first light generating unit and the second light generating unit is dimmable.
4. The illumination device as defined in any one of claims 1-3, wherein
the first light generating unit comprises a first light source (101a) associated with a first pattern projecting optics (102a) for providing the first lighting pattern, and
the second light generating unit comprises a second light source (101b) associated with a second pattern projecting optics (102b) for providing the second lighting pattern.
5. The illumination device as defined in claim 4, further comprising at least one mask (200, 600) equipped with portions (204, 604) allowing transmission of light for providing the first pattern projecting optics and the second pattern projecting optics.
6. The illumination device as defined in claim 5, wherein the mask (200) separates a first region (210a) in which the first light source (201a) is arranged from a second region (210b) in which the second light source (201b) is arranged, and at least one of a first side (220a) of the mask facing the first light source and a second side (220b) of the mask facing the second light source is at least partly reflective.
7. The illumination device as defined in claim 6, wherein both the first side and the second side of the mask are at least partly reflective.
8. The illumination device as defined in any one of claims 5-7, further comprising a plurality of masks (320, 330) symmetrically arranged in respect of each other and a plurality of light sources (301a, 301b, 301c) symmetrically distributed between the masks.
9. The illumination device as defined in claim 5, wherein the portions (604) allowing transmission of light form a periodic pattern, and the first light source (601a) and the second light source (601b) are positioned at the same side of the mask (600) at a distance from each other corresponding to about a half period in the periodic pattern.
10. The illumination device as defined in claim 4, further comprising a first mask
(102a) equipped with portions (104a) allowing transmission of light for providing the first pattern projecting optics and a second mask (102b) equipped with portions (104b) allowing transmission of light for providing the second pattern projecting optics, wherein the first mask is separate from the second mask.
11. The illumination device as defined in any one of claims 2-10, wherein the control unit is configured to individually control any one of the first light generating unit and the second light generating unit such that they can be sequentially switched on and off.
12. The illumination device as defined in any one of claims 4-10, wherein the light sources are light emitting diodes and/or side-firing light emitting diodes.
13. The illumination device as defined in any one of claims 4-12, wherein a light source is provided with a shield (206) for hindering light from the light source to be emitted in other directions than towards its associated pattern projecting optics.
14. The illumination device as defined in any one of claims 4-13, wherein at least one of the light sources is provided with a scattering exit diffuser.
15. The illumination device as defined in any one of claims 4-14, wherein the mask is provided with portions provided with a dichroic filter.
16. Method of operating an illumination device, comprising:
providing a first lighting pattern;
providing a second lighting pattern being complementary and at least partly superposed to the first lighting pattern; and
adjusting a light intensity of at least one of the first lighting pattern and the second lighting pattern.
PCT/IB2011/054886 2010-11-10 2011-11-03 Illumination device with switchable projection patterns WO2012063167A1 (en)

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EP10190641 2010-11-10
EP10190641.0 2010-11-10

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US4535394A (en) * 1983-12-08 1985-08-13 Dugre Michael A Variable color floodlight
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FR2036356A5 (en) * 1969-03-14 1970-12-24 Brizzi Albert
US4368963A (en) * 1978-06-29 1983-01-18 Michael Stolov Multicolor image or picture projecting system using electronically controlled slides
US4535394A (en) * 1983-12-08 1985-08-13 Dugre Michael A Variable color floodlight
US20060177185A1 (en) * 2001-01-29 2006-08-10 Production Resource Group, L.L.C. Three color digital gobo system
US20030035092A1 (en) 2001-08-15 2003-02-20 Brian Bramlett Light pattern projection system

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CN113448158A (en) * 2020-03-28 2021-09-28 苏州佳世达电通有限公司 Support and electronic device using same
CN113448158B (en) * 2020-03-28 2023-08-18 苏州佳世达电通有限公司 Support and electronic device using same

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