WO1997027576A1

WO1997027576A1 - Retrofit lighting system that non-invasively interacts with a host machine

Info

Publication number: WO1997027576A1
Application number: PCT/US1997/001128
Authority: WO
Inventors: Mark Bevington; Mark Lipsky; Bryan D. Haynes; Earl Cassorla; Norman Looper
Original assignee: Add-Vision, Inc.
Priority date: 1996-01-25
Filing date: 1997-01-23
Publication date: 1997-07-31
Also published as: CA2244212A1; EA001005B1; EP0876658A4; KR19990082066A; EA199800606A1; JP2000503125A; EP0876658A1; NZ331022A; AU1709097A; AU716031B2; CN1217805A; BR9707084A

Abstract

A retrofit lighting system (100), for use with a host machine (104), produces lighting effects in response to lamp power signals that are provided from the host system (104) and that would otherwise be used to power lamps (108) of the host machine (104). An EL lamp system (108) has a plurality of EL lamp cells. Sequencing circuitry (106) provides an EL lamp driving signal to independently control each of the EL lamp cells of the EL lamp system (108) such that the EL lamp cells collectively illuminate in a sequence corresponding to the EL lamp driving signal. The microcontroller (406) controls the frequency, amplitude, and duty cycle to the electroluminescent lamps (108). By changing the frequency, the microcontroller (406) alters the intensity and illumination color. By changing the amplitude, the microcontroller (406) alters the illumination intensity. Further, data signal lines are supplied from the microcontroller (406) to select which electroluminescent lamps (108) to illuminate, thereby creating animated displays. Signal conditioning circuitry (102) non-invasively samples the lamp power signals provided from the host system (104), and provides the driving signal to the EL lamp (108) in response thereto.

Description

Title: Retrofit Lighting System that Non-Invasively Interacts with a Host Machine

Copyright Notice

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

Technical Field

The present invention relates to a lighting system that interacts with a host machine, such as a gaming machine. In particular, the present invention relates to a retrofit lighting system that interacts, preferably non-invasively, with a host machine and that illuminates with a sequence corresponding to a state indication sampled from the host machine.

Background

Many machines, such as vending machines and gaming machines, illuminate one or more light bulbs on the exterior of the machine in response to internal states of the machine. For example, a slot machine illuminates various incandescent light bulbs to illuminate its "paylines" depending upon the number of coins inserted into the machine.

However, incandescent light bulbs consume large amounts of power. Thus, it may be desired to replace the incandescent bulbs with

electroluminescent (EL) lights, since EL lights consume less power.

Electroluminescent (EL) lamps are light sources that contain a special phosphor or combination of phosphors that luminesce when they are subjected to electric fields. Perhaps more significantly, it may be desired to modify the manner in which the lights are illuminated in response to the internal states of the machine. For example, the manner in which the lights are illuminated may be altered to draw people to the machine or to provide useful information.

Typically, much of the circuitry for controlling a machine's lighting system is incompatible with powering lower power light sources. In addition, the circuitry for controlling the manner in which the lights are illuminated is usually internal to the machine. As a result, it is expensive to modify the lighting system. This is especially so when the machine is a gaming machine, since state gaming laws require that gaming machines undergo extensive testing and certification after any changes are made to their internal circuitry.

In the past, EL lamps required high voltage electricity for them to operate. Because of this, bulky power supplies, inverters and/or other electronic circuitry and batteries (for cordless operation) are required to supply the appropriate electric power to cause the lamp to emit light. The power supply is usually a lot more bulky than the lamp.

Typical EL lamps are powered by high voltage (usually greater than

10 V) power supplies. These power supplies are frequently AC (Alternating Current) type supplies. Some ELs are powered directly from standard house current (typically 120 VAC). For battery rather than house current operation, usually an inverter or other circuit is required to step up and/or convert the battery's DC electricity to high voltage AC electricity.

An EL lamp display circuit may include a memory, an audio sequencer, and a counter to define segments of the EL display to be illuminated. Control of the output display in such a systems is restricted, however, by the limited data manipulation abilities of the memory and the counter. Because a fixed AC voltage wave generator drives the display, the output is further restricted in that dynamic control of the color and intensity the output display is not possible.

Summary

The present invention is a retrofit lighting system, for use with a host machine, to produce lighting effects in response to lamp power signals that are provided from the host system and that would otherwise be used to power lamps of the host machine. An EL lamp system has a plurality of EL lamp cells. Sequencing circuitry provides an EL lamp driving signal to

independently control each of the EL lamp cells of the EL lamp system such that the EL lamp cells collectively illuminate in a sequence corresponding to the EL lamp driving signal. In particular, the sequencing circuitry includes a microcontroller connected to a power supplying circuit for supplying a driving signal, the driving signal being of an appropriate magnitude and frequency to drive the electroluminescent display elements. A selection circuit receives a plurality of signals from the microcontroller and receives the driving signal from the power supplying circuit. The selection circuit selectively forwards the driving signal to each of the individual

electroluminescent display elements based on the signals received from the microcontroller. By this arrangement, the microcontroller turns each of said display elements on or off in a sequence, thereby generating animated displays. Signal conditioning circuitry non-invasively samples the lamp power signals provided from the host system and that provides the EL lamp driving signal in response thereto.

The circuit may also include load capacitors that can be selectively switched by the controller to present capactive load to the drive signal generator in addition to the capacitive load presented by the elements of the electroluminescent panel. The load capacitors may not only address a "spiking" phenomona associated with switching the drive signal from one element to another element, but may also provide compensation for differing capactive loads that result from different size elements being driven at different points in the sequence.

Brief Description of the Drawings

Fig. 1 is a block diagram illustrating a retrofit lighting system 100 in accordance with an embodiment of the invention.

Fig. 2 illustrates a gaming machine with which the retrofit lighting system 100 shown in Fig. 1 may be used.

Fig. 3 illustrates how the retrofit lighting system interfaces to the gaming machine in accordance with an embodiment of the invention.

Fig. 4 is a top-level schematic diagram illustrating an embodiment of a circuit for controlling one of the EL lamp systems of the retrofit lighting system 108 of Fig. 1.

Fig. 5 is a schematic diagram illustrating the drive signal generator of the Fig. 4 schematic in greater detail.

Fig. 6 is a schematic diagram illustrating the switching circuits of the

Fig. 4 schematic in greater detail.

Fig. 7 is a schematic diagram illustrating the microcontroller (and associated glue logic) of the Fig. 4 schematic in greater detail.

Fig. 8 is a graph that illustrates a spiking phenomena may occurs when the switching circuits are switched in a first sequence.

Fig. 9 is a graph that illustrates a second switching sequence, and employing load capacitors, to address the spiking phenomena.

Fig. 10 is a high level conceptual block diagram of an EL controller according to a further embodiment of the present invention;

Fig. 11 is a detailed block diagram of an EL controller according to the embodiment of Fig. 10;

Figs. 12A through 12D illustrate microcontroller pulse signals and EL panel driving signals;

Fig. 13 is a block diagram of an EL controller according to a still further embodiment;

Fig. 14 is a detailed block diagram of the high voltage driver of the EL controller of Fig. 13;

Fig. 15 is a timing diagram illustrating an exemplary timing sequence in the EL controller of Fig. 13;

Fig. 16 is a block diagram of an EL panel multiplexing circuit; and

Fig. 17 is a block diagram of a still further embodiment of the EL panel controller device.

Detailed Description

Fig. 1 illustrates, in block form, a retrofit electroluminescent (EL) lighting system 100 in accordance with an embodiment of the present invention. The EL lighting system consumes less power than incandescent bulbs of a host machine that are otherwise used. Alternately, even if the incandescent bulbs are used, the EL lighting system 100 can provide additional lighting effects with a minimal amount of additional power. By retrofitting a machine with the retrofit EL lighting system 100, it is quite easy to modify the manner in which lights are illuminated in response to the internal states of the machine.

In the embodiment illustrated in block form in Fig. 1, the system 100 includes three EL lamp panels 108a, 108b, and 108c (generically referred to herein as 108). Each EL lamp panel 108 includes a plurality of

independently drivable EL lamp cells. The panels are driven by an electronic control module 101. Each panel is driven by a separate sequencing subcircuit seq1, seq2 and seq3, respectively, of the electronic control module 101 and included in a sequencing circuit 106. For example, as shown in Fig. 2, if the gaming machine 104 is a slot machine, the lamp panels 108a, 108b and 108c are suitable for being located on the "top glass" 152, "reel glass" 154 and "belly glass" 156 of the slot machine 104. An additional area of the slot machine 104, designated in Fig. 2 by numeral 158, may be provided with an EL panel to draw attention to the "bill collector" function of the slot machine 104.

Each lamp of an EL panel turns on when an alternating driving current or pulsed direct current is supplied to the lamp. The intensity of the lamp varies depending upon the magnitude and the frequency of the lamp driving current, while the color of the lamps varies depends on, for example, the frequency of the driving current.

Fig. 3 illustrates how the retrofit lighting system 100 interfaces to the gaming machine 104 in accordance with an embodiment of the invention. The electronic control module 101 includes a connector 301 for connecting

(via a standard plug 303) to a standard 120V, 60 Hz alternating current power supply. In Fig. 3, a single state control signal is obtained from the gaming machine 104 for controlling the EL panel 108a, to be located on area 158 of the slot machine 104. More specifically, signals generated by the gaming machine 104 indicate an internal state of the gaming machine 104, and these state indication signals are preferably sampled non-invasively by circuitry within the electronic control module 101. That is, the state indication signals are preferably sampled without affecting the internal state of the gaming machine 104.

For example, a power signal provided from the gaming machine 104 to power an external incandescent bulb may be utilized as the state indication signal. The power signal would be sampled by tapping into the power signal where it is provided to the incandescent bulb. An example of this is shown in Fig. 3, where the power signal provided by the gaming machine 104 to an "insert coin lamp" 302 is sampled, and provided to the electronic control module 101 via a connector 305. As another example, the machine's original bulb may be left in place and a photo-sensor employed to determine when the light bulb is illuminated. A problem with this is that the original bulb may burn out. As yet another example, a coil may be provided surrounding the wire that provides the power signal to the bulb and the magnetic field generated by current in the wire measured by the coil and utilized as the state indication signal. In each case, the goal is to non-invasively sample the power signal to the bulb. (Alternately, but non-optimally, a state indication signal could be provided directly from the microcontroller or other circuitry of the gaming machine 104.)

In response to the state indication signal provided from the gaming machine 104, the electronic control module 101 generates lamp panel driving signals for driving one of the EL lamp panels (in this case, EL panel 108a shown in Fig. 1). As shown in Fig. 3, the lamp panel driving signals are provided to the EL lamp panel 108a from the electronic control module 101 via an interconnect cable 309. The lamp panels are commercially available from MKS of Bridgeton, New Jersey.

Electroluminescent (EL) lamps come in a number of forms, in addition to EL panels, such as EL lamp threads or filaments. The lighting system may include any of these forms of EL lamps. An EL panel is an EL lamp strip on a backing sheet. The EL panels are preferably made by selective deposition of a phosphor compound and selective deposition of conductive rear electrodes (e.g., polymer materials containing high loadings of silver particles). Multiple sections of this phosphor-electrode arrangement can be deposited on the panel to form patterns. Each section is individually connected to a power supply, so that they may be independently turned on or off, thus facilitating animation. Although the present embodiments are described referring to EL panels, single or multiple EL lamp filaments may easily be substituted for the EL panels.

A detailed embodiment of the electronic control module 101 is now described with reference to Fig. 4 through 7. Fig. 4 is a top-level schematic diagram that shows a more detailed embodiment of the electronic control module 101 than is shown in Fig. 1. As shown in Fig. 4, the electronic control module 101 is for causing selective illumination of the cells of the EL lamp panel, in an animated sequence, at the area 158 of the slot machine 104. Referring still to Fig. 4, host machine interface circuitry 102 receives the state indication signal (e.g., a sample of the power signal used to power an incandescent light bulb) from the gaming machine 104 and conditions the sampled signal as appropriate (e.g., by shifting the level of the sampled signal) for input to a microcontroller 406. The details of the conversion are dependent upon the particular gaming machine 104 and, more particularly, the level of the sampled signal.

The conditioned state indication signal is provided to the

microcontroller 406 via an opto-isolator 404 or 405). The opto-isolators 404 or 405 isolate the electronic control module 101 from the gaming machine

104 so that the gaming machine 104 internal circuitry is protected from being affected by glitches that may develop in the electronic control module 101 (e.g., as a result of a shock caused by a release of static electricity from a player of the game machine 104). If the electronic control module 101 is connected directly to the internal electronics of the gaming machine 104, it is likely that any electro-static discharge to the electronic control module 101 will be directly coupled into the gaming machine 104, disrupting its process and resulting in a "hopper" dump.

A drive signal generator 408, powered by a power supply 410, provides a sinusoidal driving signal for driving the EL cells via EL drivers circuitry 412 and ultimately via the pins of connector 416. As described in appl. no. 08/591,014, incorporated by reference above, the microcontroller 406 selectively enables switching circuits within the EL drivers circuitry 412 in response to the conditioned state indication signal to cause the switching circuits to selectively provide drive signals to the EL cells. (The switching circuits are described later with reference to Fig. 6.) As a result, the EL cells are illuminated in an animated sequence. Microcontroller 406 is connected to inverter 408 via an ENABLE-H signal. By asserting the ENABLE-H signal, microcontroller 406 can disable drive signal generator 408 from providing the driving signal. The details of the drive signal generator 408 in accordance with one embodiment of the invention is shown in greater detail in Fig. 5. An inverter 502 provides the sinusoidal driving signal. The capacitors C6 and C6A provide a load capacitance that limits the maximum output voltage from the inverter 502.

A low voltage monitor 504 monitors the amplitude of the sinusoidal driving signal provided from the inverter 502. Specifically, when EL lamps/cells fail, they typically develop either direct and/or partial shorts. This can severely overload the inverter 502, as it tries to supply a sufficient current to drive the shorted EL cell. The low voltage monitor 504 is a voltage comparator circuit. It converts the sinusoidal output of the inverter 502 to a DC voltage that is proportional to the inverter 502 output voltage. When an EL cell shorts and the inverter 502 output drops below the value set by resistors R11, R12 and R13, the output of the low voltage comparator 504, LVOLT-H, is asserted. The LVOLT-H output is optically coupled to the microcontroller 406. The microcontroller 406 is programmed to monitor the LVOLT-H signal and, upon detecting that the LVOLT-H signal has been asserted, disable the inverter 502. This prevents excess currents, which would be drawn through the inverter 502, from causing permanent damage to the inverter 502.

A zero crossing detector 506 may be provided to detect when the drive signal provided from the inverter 502 crosses a zero voltage amplitude. When the zero crossing is detected, zero crossing detector 506 provides a ZEROX-E control signal to the RB1 input of the microcontroller 406 (Fig. 4). The microcontroller switches the switching circuits within EL drivers circuitry 412 to begin providing drive signals via connector 416 only when the drive signal provided from the inverter 408 has about a zero voltage amplitude. In this way, the EL cells can be protected from sharply increasing drive signal inputs (i.e., spikes). In addition to causing potentially annoying visual "flashes", such drive signal spikes may cause breakdown of the capacitance within the EL cells and render the EL cells inoperable.

A portion of a detailed embodiment of the EL drivers circuitry 412 is now described with reference to Fig. 6. In particular, the EL drive signal generated by the drive signal generator 408 is provided to an AC HOT input of the EL drivers circuitry 412. Each of a plurality of switching circuits 602a through 602i includes a switch control input (RC0 through RC7 and RB7, respectively) and a drive signal output (DRC0 through DRC7 and DRB7, respectively). Each of the switching circuits 602a through 602i is also connected to receive the AC HOT input to receive the EL drive signal generated by the drive signal generator 408. The switching circuits 602a through 602i include four rectifier diodes and one bipolar junction transistor.

In response to a program being executed by the microcontroller, the microcontroller asserts various ones of its switch control outputs, RC0 through RC7 and RB7, connected to the switch control inputs, RC0 through RC7 and RB7, respectively, of switching circuits 602a through 602i, respectively. In response, when the switch control input of a particular switching circuit is asserted, that switching circuit passes the drive signal from AC HOT to the output of the switching circuit. Referring back to Fig. 4, it can be seen that each of the switching circuits 602a through 602i is connected, via connector 4016, to a separate one of the EL cells of the "bill collector" EL panel located at area 158 of the gaming machine 104 (Fig. 2).

Referring still to Fig. 6, the supplemental switching circuits 604a and 604b are now discussed. The supplemental switching circuits 604a and 604b respond to switching signals provided from switch control outputs RB5 and RB6 of the microcontroller 406 to switch control inputs RB5 and RB6, respectively, of supplemental switching circuits 604a and 604b, respectively. Specifically, the supplemental switching circuits 604a and 604b passes the drive signal from AC HOT to the output DRB5 and DRB6 of the

supplemental switching circuit, 604a and 604b, respectively, whose switch control input RB5 and RB6, respectively, is asserted. The drive signal, via outputs DRB6 and DRB7, to load capacitors C7 and C7A or to load capacitors C8 and C8A, respectively.

The reasons for providing the drive signal to load capacitors C7 and C7A or to load capacitors C8 and C8A is now discussed. The inverter 502 (Fig. 5) of drive signal generator 408 is both load dependent and self-compensating. (In a preferred embodiment, the inverter 502 is an "NS" series inverter provided by NEC.) That is, the inverter 502 includes circuitry such that the frequency of the sinusoidal driving signal that the inverter 502 provides is determined by the capacitance of the load being driven at any particular point in a lighting sequence (nominally, the load of the EL cell or cells being driven via the particular one or ones of the switching circuits, of EL drivers circuitry 412, that is selected to provide a drive signal). In addition, the capacitance of an EL cell changes as the EL cell ages. The inverter 502 senses the capacitance change and adjusts the frequency of the driving signal generated such that the EL cell is illuminated at a relatively constant brightness even as its capacitance changes.

Since the capacitance load of an EL cell is largely determined by its size, when the plurality of EL cells being driven in a sequence by the single inverter 502 are different sizes, the frequency of the sinusoidal driving signal provided by inverter 408 will fluctuate depending on the size (and, thus, capacitance) of the EL cell (or combinations thereof) being driven. As a result, if no accommodation is made for the differing loads presented by different combination of EL cells, the brightness with which each EL cell is illuminated will fluctuate widely in comparison to each other. This phenomena is visually unappealing.

However, by adding the load capacitors C7 and C7A or to load capacitors C8 and C8A to the capacitive load experienced by the inverter 502, the inverter 502 experiences a substantially constant capacitive load throughout the illumination sequence. By maintaining the substantially constant capacitive load, the frequency of the sinusoidal drive signal provided by the inverter 502 can be maintained substantially constant. As a result, the brightness with which the EL cells are illuminated during the sequence is maintained at each time point in the lighting sequence. This allows the inverter 502 to "sense" the capacitance change for each particular EL cell, due to aging, and compensate for it.

The number of supplemental switching circuits and load capacitors, the capacitance values of the load capacitors, and the arrangement of load capacitors required to even out the capacitance load on inverter 502 depends upon the variation in sizes of the EL cells being driven and the desired percentage tolerance of brightness variations. A sequence of switching supplemental switching circuits, to include the load capacitors in the load experienced by inverter 408, can be predetermined and included in the sequencing program executed by microcontroller 406. That is, in addition to controlling the switching circuits within the EL drivers circuitry 412 to illuminate the EL cells, the microcontroller 406 can also be pre-programmed to control the supplemental switching circuits to selectively cause various ones (or combinations) of load capacitors to load inverter 502 as a function of which one or ones of the EL cells is illuminated.

In the embodiment shown in Fig. 4, capacitors C8 and C8A together have an effective capacitance of .01 μF and capacitors C7 and C7A together have an effective capacitance of .022 μF. Thus, there are four variations of load capacitance which can be achieved by selectively enabling DRVR #A and DRVR #B, as shown below:

The actual values for the load capacitors and their configurations may be determined qualitatively (i.e., by experimenting with different values and qualitatively reviewing the resulting illumination sequence). Preferably, however, the surface areas of the EL cells being driven during the

illumination sequence can be quantitatively correlated to an equivalent capacitance. A memory (e.g., a read-only memory) may be provided. A table in the memory includes a plurality of table entries, each table entry corresponding to a step of the lighting sequence and indicating which load capacitors to switch on during the corresponding step of the sequence.

Fig. 7 schematically illustrates an embodiment of the microcontroller

406 and associated glue logic.

Fig. 8 illustrates a phenomena by which, if the microcontroller 406 turns off the switching circuit (i.e., one of 602a through 602i) corresponding to a first EL cell (referred to as "CELL #1" in Fig. 8) a short time (even as short as a few microseconds) before turning on the switching circuit corresponding to a second EL cell (referred to as "CELL #2" in Fig. 8) and the sinusoidal drive signal generated by the inverter 502 is at a peak, then the drive signal may spike (to greater than 400 V) due to the sudden decrease in capacitive load and potentially damage either or both of the inverter 502 and EL cell #2.

Fig. 9 illustrates how the spike in the drive signal can be avoided even without using the zero-crossing detector 506. First, the switching circuit corresponding to CELL #2 is switched on before the switching circuit corresponding to CELL #1 is switched off. Before switching on the switching circuit corresponding to CELL #2, the switching circuit (or circuits) corresponding to a load capacitor (or capacitors) is switched on. The places a large capacitive load on the inverter 502 such that a spike will not occur when the switching circuit corresponding to CELL #2 is later switched on (e.g., 0 to 5 μs after the switching circuit corresponding to the load capacitor is switched on. Finally, after enough time has passed for the load on the inverter 502 to stabilize (e.g., about 100 μs), CELL #1 is switched off.

Appendix A is a source listing of assembly language code that may be executed by the microcontroller 406 to execute a sequence.

In a fully integrated driving circuit, a microcontroller may control not only the switching on of each lamp, but also the intensity of the lamp, and the color of the lamp. The microcontroller 406 can be used to create animated displays on all sorts of one, two, and three dimensional light emitting objects. Examples of such objects include clothing, works of art, molded parts, and informational displays. In clothing, for example, electroluminescent threads can be used for animated logos, designs, or other accents.

A conceptual block diagram of a further embodiment of an EL panel controller device is shown in Fig. 10. In this embodiment, microcontroller 1 100 controls the color, intensity, and switching sequence of a plurality of EL lamps 1102. An EL driver 1106 supplies an alternating current to the EL panels under the control of the microcontroller 1100. A plurality of solid state switches 1 104 connect the EL driver 1106 to the EL panels 1 102. I/O pins 1110, labeled 1 through n of microcontroller 1100 output control signals to control lines of the switching circuits 1104. Switching circuits 1 104 control the circuit of electrical energy flowing through EL driver 1 106 and

EL panels 1102.

Control lines 1108 are optional. If installed, control lines 1108 connect the microcontroller 1100 to the EL driver 1106. Through control lines 1108, the microcontroller 1100 controls the frequency and magnitude of the current output by the EL driver 1106. The frequency, the duty cycle, and intensity of the output of the driver 1106 will determine the color and intensity of the individual EL lamps 1102.

A more detailed block diagram of the EL panel controller of Fig. 10 is shown in Fig. 1 1.

The microcontroller 1 100 preferably has a low cost and a low peripheral component count. A commercially available microcontroller such as the PTC16C55 or the PIC16C57 from MICROCHIP could be used as microcontroller 1100. Any suitable microcontroller or microprocessor, however, could be substituted in its place.

A voltage regulator 1202 connects the battery to the microcontroller

1100 and regulates the voltage from the battery to the level required to power the microcontroller 1100. In this example, regulator 1202 supplies the microcontroller 1100 with 5.0 volts DC.

A timing circuit 1204, such as a ceramic resonator or quartz crystal (XTAL), resistor, and/or capacitor(s), is connected to provide timing signals to the microcontroller 1100. Variations on this embodiment containing an on-board timer in microcontroller 1100 may not require a timing circuit.

Push-button(s) 1206 are connected to the microcontroller to allow a user to control functions of the microcontroller such as on/off, pattern select, color, and output timing adjustment.

The EL driver circuit 1106 is composed of an oscillator (or function generator) 1208, a power amplifier 1210, and a transformer 1212. The transformer 1212 connects the oscillator 1208 and the power amplifier 1210 to the output of the EL driver circuit 1106 (Fig. 10). The power amplifier 1210 receives the output of the oscillator 1208. This signal is then amplified by power amplifier 1210 and drives the primary winding of the transformer 1212. The oscillator 1208 may supply, for example, sinusoidal, square, or sawtooth waveforms. A typical driving signal transmitted from the transformer 1212 may be, for example, a sinusoidal signal with a frequency of 1000 Hz and an amplitude of 35 volts.

The type and frequency of the waveforms output from the oscillator 1208 may be controlled by the microcontroller 1100 through control line(s) 1214. Similarly, the amplification of the power gain 1210 may be controlled by the microcontroller 1 100 through control line(s) 1216.

Changing the frequency of the driving signal for an EL lamp affects the color and the intensity. Color swings from lime green or deep green to a blue or purple color are possible solely by altering the frequency and the duty cycle of the driving signal. This corresponds to a shift of approximately 150 nm in the visible light spectrum.

Changing the amplitude of the driving signal affects the intensity.

The perceived intensity may also be altered by adjusting the duty cycle of the switching signals (explained below).

Switching circuits 1104, connected to and controlled by I/O pins 11 10, connect their respective EL panels 1102 to the EL driver 1 106. Switching circuits 1104 each contain a high-voltage transistor 1218. The base of each transistor 1218 is connected to a resistor 1220 which is connected to the microcontroller 1100. The emitter of each transistor 1218 is connected to ground, and the collector of each transistor 1218 is connected to diode bridge 1222. Each EL panel 1102 is connected between one of the diode bridges 1222 and one end of the secondary winding of the transformer 1212.

Switching circuits 1 104 are duplicated for each EL panel controlled by an I/O pin of microcontroller 1100. The number of circuits 1104 is limited by the number of output pins available on the microcontroller 1100, although, of course, not all of the output pins have to be used.

In operation, the embodiment of Figs. 10 and 11 functions as follows.

Microcontroller 1100 controls the switching circuits 1104 through I/O pins 11 10. A high output ("1") on any of the I/O 1110 closes the switching circuit, which allows EL driving current to flow through the switch's corresponding EL panel 1102, illuminating the lamp. A low output ("O") on any of the I/O pins 1 110 opens the switching circuit, which inhibits EL driving current flow through the switching circuit's corresponding EL panel 1102, causing the switch to turn off. Specifically, in reference to Fig. 1 1, a high output ("1 ") causes current to flow through the resistor 1220 which turns on the transistor 1218. This allows current to flow through the transistor 1218, the diode bridge rectifier 1222, and the EL panel 1 102, thereby illuminating the EL panel. Similarly, a low output ("O") causes the EL panel to extinguish.

If control lines 108 are implemented, microcontroller 1100 controls the frequency and amplitude of the driving voltage output by EL driver circuit 1106. In this manner, microcontroller 1100 controls the color and intensity of the EL panel output display.

The push button(s) 1206 can be used execute microcontroller on/off, pattern select, and timing. For example, tapping the button once will turn the controller on for a predetermined period of time after which the controller may execute a sleep instruction and, in essence, turn itself off. Pressing the push button 1206 a second time before the sequence has ended commands the display to display continuously. Pressing the push button 1206 a third time stops the display and reset the controller into standby mode. An indicator light can be used to flash the present state of the controller.

Microcontroller 1100 uses its I/O pins 1110 to control the state (i.e., on or off) of each EL panel to output a sequence corresponding to a preprogrammed animation sequence to be displayed on the EL panels. When the microcontroller outputs the next word in the animation sequence to its I/O pins, the EL panels change to a state corresponding to the new pattern. In this manner, preprogrammed display sequences are displayed on the EL panels.

Since each of the EL panels is coupled to an I/O pin on the microcontroller 1100, a complete state of the EL panels is defined when the microcontroller 1100 places an output on each I/O pin 1110 coupled to an EL panel. Animation of the EL panels is achieved by continuously updating the state of the I/O pins, 11 10 outputs.

Two software approaches have been used to time sequence the I/O pins' 1 110 patterns. The first approach is to construct a table of words, encoded as part of the microcontroller programming, that define the state of all the panels for each step in the sequence. For example, a three step sequence might be: all panels on, every other panel on, all panels off. If 15

EL panels are used, this is represented by the table of states:

1 11 1 11 1 1 1 11 11 11

10101010 1010101

00000000 0000000

The microcontroller 1100 simply outputs the first line in the table to the I/O pins 1 110, turning all of the EL panels on. After waiting a predetermined period, microcontroller 1 100 transmits the next line in the table to the I/O pins 1 110, turning every other EL panel off. After another predetermined delay, the last line is transferred, turning all of the EL panels off.

A second sequencing approach involves initializing the states of the I/O pins 1 1 10 and then computing subsequent states based on the previous states and a selected bit manipulation function. For example, a "chase" pattern could be executed by initializing the states of the I/O pins 1 110 to:

1011 1111

and then executing a rotate right instruction on this port. The next output sequence would then be:

1 101 1111

The bit manipulation function used may be any combinatorial or sequential function executable by the microcontroller 1100. The approach has the potential advantage of saving memory space by reducing the table size required to hold needed states.

A common problem in the prior art associated with EL lamps is that when the lamps are driven for an extended period of time at a high frequency, they emit heat, and may eventually burn out. The heating problem can be alleviated with the present invention by either having the microcontroller periodically turn the hot EL panel off or, if the EL panel is to be on for an extended period of time, the on signal can be pulsed.

Figs. 12A and 12D illustrate pulse signals from microcontroller 1100 for controlling switching circuit 1 104. These signals can be generated by microcontroller 1100 as a sub-signal of an EL panel 1102 on-period, or equivalently, external circuitry could be used to pulse an on signal from the microcontroller 1100.

The human eye has a retentivity such that a light flashing faster than about 60 Hz is not perceived as flashing. Because of this, as long as the frequency of the on signal from I/O pins 1110 is pulsed at least at 60 Hz, the illuminated EL panel will appear to be continuously on.

Fig. 12A illustrates a 50 percent duty cycle pulse signal flashing at 60 Hz. During the high ("on") periods, the high frequency signal from the transformer 1212 (shown in Fig. 12B) is passed through switching circuit 1104, which are controlled by pulse signal 12A. The resultant signal (shown in Fig. 12C) drives the EL panel 1102, thus illuminating it. Even though the EL panels may be being driven at a much higher frequency from the driver 1 106, they are only actually driven half the time because they are not driven when the pulse signal in Fig. 12A is low. This significantly reduces undesirable heating of the EL panels.

Because the pulse signal in Fig. 12A is generated by the

microcontroller 1100, the duty cycle can easily be changed. An illustration of a 75 percent duty cycle pulse signal flashing at 60 Hz is shown in Fig. 12D. Changing the duty cycle of the pulse signal allows one to vary the Perceived intensity of the emitted light. For each complete period of the pulse signal in Fig. 12D, three quarters of the driving signal in Fig. 12B would get passed to the EL panels 1102 because the signal is on three-quarters of the time and off one-quarter of the time. Because the human eve is not completely linear with respect to duty cycle and perceived intensity, the 25 percent increase in the duty cycle between Figs. 12A and 12D will be perceived by an observer as slightly less than a 25 percent intensity increase.

The above described novel EL panel controller device may be packaged as a small, light, fully integrated unit. Further, dynamic control of color, intensity, perceived intensity, and heat dissipation for multiple EL panels or filaments is possible, thus allowing for a wide range of animation capabilities.

A block diagram of a further embodiment of the EL panel controller device of the present invention is shown in Fig. 13. In this embodiment, EL Panels 1412 are connected to high voltage driver 1410. Three EL Panels are shown here for illustrative purposes, more or less could easily be used.

Further, instead of using three separate panels, a single panel divided into multiple sections could equivalently be used.

Microcontroller 1400 receives power from voltage regulator 1404, which is in turn connected to battery 1406. Switch(es) 1402 connect to microcontroller 1400 and can be used for various control functions such as on/off, pat tern control, timing control etc. Voltage regulator 1408 is a high voltage regulator for providing power to the high voltage driver 1400.

Typically, 200 volts is provided to driver 1410, although depending on the particular lighting requirements of there EL cases, a significantly higher or lower voltage may be used.

In operation, microcontroller 1400 controls the illumination of the EL Panels 1412 through driver 1410 using an output enable (OE) line, a polarity line, a data line, and a clock line. The data line is preferably a single line which serially loads data into a shift register contained in the driver 1410. For applications that require a faster load time, more data lines may be used.

Fig. 14 is a detailed block diagram of the high voltage driver 1410. Driver 1410 contains a shift register 1500. The shift register 1500 receives information from the data line in synchronism with the clock. Other shift register input lines, such as a register clear line or a shift register direction control line, although not shown, may also be input to the shift register 1500 from microcontroller 1400.

Data output from shift register 1500 is input to logic circuits 1502. Based on the output enable signal, the input from the shift register 1500, and the polarity signal, the logic circuits 1502 open or close MOSFETS 1504, 1506. Depending on the states of their MOSFETS, the EL Panels 1412 will charge or discharge, causing them to illuminate.

In operation, microcontroller 1400 transmits the clock, polarity, and output enable signals to each logic circuit 1502 in high voltage driver 1410. The clock and data signals are serially input to shift register 1500. Shift register 1500 shifts data synchronously with the clock signal from the first segment to the second segment and finally to the third segment. At any given time, the microcontroller 1400 controls the shift register 1500, data and clock signals so that only a single "1", or ON bit, is present in the shift register 1500. A "1" in one of the three positions in the shift register 1500 corresponds to a potential ON state of its corresponding logic circuit 1502.

At each clock pulse, the "1 " is shifted down the shift register 1500. In this manner, the microcontroller 400 can control the EL panel 1412 to be activated. A "O", or OFF bit, corresponds to a potential OFF state in the corresponding logic circuit 1502. When in the OFF state, the logic circuits 1502 turn off the MOSFETS 1504 and 1506, thus presenting a high impedance state to its EL Panel 1412.

The OE signal is an active low line. When this line is low, the logic section 1502 corresponding to the "1" in the shift register 1500 either charges or discharges its corresponding EL panel 1412, depending on the polarity signal. When OE is high, all of the logic circuits 1502 control their corresponding MOSFETS 1504 and 1506 so that the EL panels 1412 see a high impedance state at high voltage driver 1410. In this state, none of the panels 1412 appreciably discharge or charge.

The polarity line is used to select the polarity of the charge experienced by the selected panel 1412 (i.e., the panel that has a

corresponding "1" in the shift register). The EL panels 1412 emit light only when they undergo a change in potential. When a panel is selected by a "1" in the shift register and the output enable is enabled, the panel is charged if the polarity is high by turning MOSFET 1504 on and MOSFET 1506 off, or discharged if the polarity is low by turning MOSFET 1504 off and MOSFET 1506 on. Because the EL panels 1412 store the charge inputted from the DC voltage source (they act like capacitors), the microcontroller 1400 preferably alternates the polarity line between successive selections of an EL panel.

Fig. 15 is a timing diagram, illustrating the interaction of the clock, data, polarity, and output enable signals. Timing intervals t1 through t3 are labeled horizontally across the top of Fig. 15. In interval t1, data signal "1" is preferably loaded into the first segment of shift register 1500 on the rising edge of the clock. Because the output enable is disabled, all of the

MOSFETS 1504, 1506 are off (high impedance state). At this point, EL panels 1412 effectively "see" open circuits when looking into driver 1410.

This means that none of the EL panels 1412 are charging or discharging.

At time interval t2 the data signal is low, so the shift register 1500 shifts the previously loaded " 1 " to the second segment. The output enable is again disabled, therefore all of the MOSFETS 1504, 1506 are off.

At the beginning of t3, the output enable is enabled. The "1 " in the shift register 1500 second segment is now latched into its logic circuit which then turns one of MOSFETS 1504, 1506 on. The MOSFET to be turned on is determined by the polarity signal. In this example the polarity signal is now high, which corresponds to turning MOSFET 1504 on. This allows current to flow from the power source to the middle EL panel, causing it to charge and emit light. The next time the microcontroller activates the middle EL panel, it will do so with the polarity signal low. This will clause

MOSFET 1504 to go off and MOSFET 1506 to go on, allowing current to flow from the EL panel and causing it to emit light.

The clock signal controls the frequency at which the driving circuit

1410 is operated. Because the clock signal is controlled by the

microcontroller 1400, its frequency and duty cycle can easily be varied by the software controlling the microcontroller. Typical operating frequencies may range from 100 Hz to 2000 Hz. Changing the frequency of the clock signal affects the intensity and the illumination color of the EL panels in a manner similar to that in the Fig. 10 embodiment.

By controlling the clock, data, polarity, and output enable lines in a pre-programmed sequence, the microcontroller 1400 controls the EL panels color, intensity, and state, thereby producing animated visual displays.

A block diagram of a still further embodiment of the EL panel controller device of the present invention is shown in Fig. 17. In this embodiment, EL panels 1806 are connected to high voltage driver 1800. High voltage driver 1800 is located in a circuit similar to that of high voltage driver 1410 shown in Fig. 13. In this embodiment, however, data lines 1802a through 1802n are input from the microcontroller 1400 instead of the

OE, polarity, and clock of the Fig. 13 embodiment. Solid state switching circuits 1804a through 1804n are controlled by data lines 1802a through 1802n respectfully and connect EL panels 1806 to either a high DC input voltage or to ground.

In operation, a high ("1") value on data line 1802a causes the solid state switching logic 1804 to connect its corresponding EL panel to the high DC voltage, charging the EL panel and causing it to emit light. When the microcontroller 1400 changes the value on input data line 1802a to a low ("0") value, the solid state switching logic 1804a connects its corresponding EL panel to ground, discharging it and causing it to emit light.

Alternatively, instead of having the microcontroller independently control both the charging and discharging of the EL panels 1806, additional circuitry could be implemented in the solid state switching circuits 1804a through 1804n to detect a change in the value of the data control lines from a low to a high value. When the change is detected, the solid state switching circuit will then automatically pulse the high voltage to the EL panel 1806. This is advantageous to the operator because he does not have to concern himself with programming the microcontroller to alternatively charge and discharge the EL panel, since this is automatically performed by the switching circuits 1804a through 1804n. Fig. 16 illustrates a multiplexing circuit for simulating one EL panel by altematively switching between two panels. Alternating switch 1700 connects the EL panel 1702 driving power supply to one of the two EL panels. The switch 1700 periodically switches between panels so that neither panel is driven for an extended period of time. The switching action may be based on an external clock signal, an internal clock signal, or the power-in signal, depending on the particular application. By multiplexing the driving signal to the two EL panels as described above, two EL panels are used to simulate one panel driven at twice the frequency of either of the individual panels. At high driving frequencies, this has been found to significantly reduce EL panel heat generation and therefore increase the EL panel's lifetime. This multiplexing arrangement can be implemented in either of the embodiments previously described.

The apparatus and methods described above comprise preferred embodiments of the present invention. However, it will be apparent to those skilled in the art that various modifications and variations can be made in the method or apparatus of the present invention and in construction of the embodiments without departing from the scope or spirit of the invention. As a first example, the microcontroller 1400 may be used to dynamically control the voltage regulator 1408. This would enable the microcontroller to exert further control over the EL panel illumination intensity. As a second example, instead of the oscillator, power amplifier, and transformer sections used in the Fig. 10 embodiment, a conventional inverter design could be used, provided that the output stage is able to float with respect to the input power.

Claims

What is claimed is:

1. An apparatus for controlling a plurality of electroluminescent display elements to create animated displays, the apparatus comprising:

a microcontroller;

a power supplying circuit for supplying a driving signal, the driving signal being of an appropriate magnitude and frequency to drive the electroluminescent display elements; and

a selection circuit connected to receive a plurality of signals from the microcontroller and to receive the driving signal from the power supplying circuit, the selection circuit selectively forwarding the driving signal to each of the individual electroluminescent display elements based on the signals received from the microcontroller,

wherein the microcontroller turns each of said display elements on or off in a sequence, thereby generating animated displays.

2. The controlling apparatus of claim 1, wherein the magnitude and frequency of the driving signal emanating from the power supply circuit can be varied to thereby alter the color and intensity of light emanated by the electroluminescent display elements.

3. The controlling apparatus of claim 2, wherein the magnitude and frequency of the driving signal is dynamically controlled by the microcontroller.

4. The controlling apparatus of claim 1, wherein for each of said electroluminescent dismay elements, the panel selection circuit selects whether to forward the driving signal based on a circuit comprising:

a resistor connected to the microcontroller at one end;

a transistor having a base, emitter, and collector, the transistor being connected to the other end of the resistor at the transistor base and the transistor being connected to the power supplying circuit at the collector end, the transistor being in the on state when the microcontroller allows current to flow through the resistor; and

A diode bridge connected to the collector of the transistor and to said each of the electroluminescent panels.

5. The controlling apparatus of claim 1, wherein the

microcontroller is connected to a push button switch allowing the user to input functions to be performed by the microcontroller.

6. The controlling apparatus of claim 1, wherein the power supplying circuit further comprises:

a function generator for generating periodic signal;

a power amplifier, connected to the function generator, for amplifying the periodic signals; and

a transformer connected to the power amplifier.

7. The controlling apparatus of claim 1, wherein the

electroluminescent display elements are electroluminescent filaments.

8. The controlling apparatus of claim 1, wherein the

electroluminescent display elements are electroluminescent panels.

9. An apparatus for controlling an electroluminescent panel to create animate displays, the apparatus comprising:

a power supply for supplying high voltage power;

a microcontroller for supplying a timing signal, a data signal, and a polarity signal; and

a driver circuit operating synchronously with the timing signal and receiving the data signal and the polarity signal from the microcontroller, the driver circuit causing the electroluminescent panel to illuminate if the data signal is high and the polarity signal is high by charging said

electroluminescent panel from said power supply and the driver circuit causing the electroluminescent panel to illuminate if the data signal is high and the polarity signal is low by discharging said electroluminescent panel; wherein the microcontroller controls the color of the

electroluminescent panel by varying the frequency of the timing signal.

10. The controlling apparatus of claim 9, further comprising a second EL panel and a multiplexor circuit, wherein based on the timing signal the multiplexor alternatively selects one of the electroluminescent panel and the second electroluminescent panel whereby an expected illumination life of the electroluminescent Dane! and the second electroluminescent panel is increased.

11. The controlling apparatus of claim 9, wherein the

microcontroller controls the color by varying the duty cycle of the timing signal.

12. .An apparatus for controlling electroluminescent panels to create animated displays, the apparatus comprising:

a power supply supplying high voltage DC power;

a voltage ground;

a microcontroller supplying signal lines for controlling on and off state of the panels; and

solid state switching logic coupled to the power supply and the panels, receiving the signal lines from the microcontroller, and for alternatively charging the panels from the power supply and discharging the panels to the voltage ground based on the signal lines, wherein the panels emit light during the charging and discharging operations.

13. A retrofit electroluminescent (EL) lighting system, for use with a host machine, to produce lighting effects in response to lamp power signals that are provided from the host system and that would otherwise be used to power lamps of the host machine, the retrofit lighting system comprising: an EL lamp system having a plurality of EL lamp cells;

sequencing circuitry providing an EL lamp driving signal to independently control each of the EL lamp cells of the EL lamp system such that the EL lamp cells collectively illuminate in a sequence corresponding to the EL lamp driving signal; and

signal conditioning circuitry that non-invasively samples the lamp power signals provided from the host system and that provides the EL lamp driving signal in response thereto.

14. A retrofit electroluminescent (EL) lighting system, for use with a host machine, to produce lighting effects in response to lamp power signals that are provided from the host system and that would otherwise be used to power lamps of the host machine, the retrofit lighting system comprising: an EL lamp system having a plurality of EL lamp cells;

signal conditioning circuitry that samples the lamp power signals provided from the host system and that provides the EL lamp driving signal in response thereto.