Electroluminescent diode lighting device comprising a communication device and installation comprising one such device

ES 2 289 348 T3

DESCRIPTION

Lighting device with light emitting diodes that includes a communication and installation device that includes such a device.

Technical scope

The invention relates to a lighting device comprising at least one light emitter with an electroluminescent diode intended to emit white light producing initial radiation and secondary radiation resulting from the excitation of at least one layer of material that reacts to said initial radiation, electronic control means connected to said at least one light emitter with an electroluminescent diode to control lighting and at least first communication means connected to said control means. The invention also relates to a lighting installation that includes an electrical supply line to supply at least one device of this type.

State of the art

Known lighting devices that include a communication device use light-emitting diodes to emit light communication signals.

This type of device is mainly described in patent application US2002 / 0048177. Said devices are used with information display or signaling devices in association with receivers of the sound or visual type.

However, the known devices cannot be applied to good quality lighting. In fact, such color diode lighting devices do not allow to obtain a good color rendering. Furthermore, overlapping communication signals runs the risk of altering the quality of light and making changes in color and intensity visible.

In lighting devices with electroluminescent diodes that emit white light, the diodes emit a first light radiation whose color is close to blue or ultraviolet. The first radiation mainly excites a layer of phosphors or other fluorescent materials that emits a second radiation in colors of higher wavelengths in the visible spectrum, for example close to yellow or green. Thus, the mixture of the first and second radiation gives a good quality white light to be used in lighting.

However, the control of light-emitting diodes that emit white light to emit communication signals at the same time as light for illumination poses problems of light quality and transmission speed. In fact, phosphor fluorescence has a response time that is too high to allow signal emissions greater than 1 megabit per second. Furthermore, even at lower speeds, a modulation of the first radiation modifies the white color resulting from the mixing of the first and second radiation.

Presentation of the invention

The object of the invention is a lighting device that includes a communication device that allows a high transmission speed and / or a good quality white light emission, as well as an installation equipped with such a device.

In a device according to the invention, the electronic control means control the supply of at least one light emitter with an electroluminescent diode to emit a light signal modulating said initial radiation as a function of a communication signal provided by the first means of communication, said modulation light signal being intended to be received by light signal receiving means sensitive to the initial radiation.

In a preferred embodiment, the lighting device includes reception means comprising a sensor sensitive to the initial radiation connected to reception signal processing means.

Advantageously, the reception means include optical filtering means to pass a light signal corresponding to an initial radiation and to reject secondary radiation.

Preferably, the reception means comprise electronic filtering means to reduce or suppress a continuous component of a signal that represents an optical signal received by the reception means.

Preferably, the electronic control means control the supply of at least one light emitter with an electroluminescent diode to emit a modulated light signal of said initial radiation by superimposing a continuous component and a modulation signal representing a communication signal.

Advantageously, the DC component depends on a value representing the communication signal.

ES 2 289 348 T3

Advantageously, the amplitude of the modulation signal depends on a value representing the communication signal.

Advantageously, the electronic control means include compensation means to compensate for color variations in illumination.

In a particular embodiment, the lighting device comprises at least one red light emitter with an electroluminescent diode and / or at least one blue light emitter with an electroluminescent diode controlled by the electronic control means.

Preferably, the electronic control means comprise means for controlling the color temperature of the light.

Advantageously, the lighting device includes at least one light collector connected to the control means for regulating the light intensity, the color rendering index and / or the color temperature of a light intended for lighting.

Advantageously, the lighting device includes at least one current sensor to provide the control means with a signal representing a current flowing inside at least one emitter and to regulate a current that must be supplied to said emitter.

A lighting installation according to an embodiment of the invention comprises an electrical supply line to supply at least one lighting device such as the one defined above and at least one electrical appliance connected to a receiver that comprises a sensor sensitive to the initial radiation.

Advantageously, said receiver is integrated in said at least one electrical appliance.

Brief description of the drawings

Other advantages and characteristics will emerge more clearly from the following description of embodiments of the invention, offered by way of non-limiting examples and represented in the attached drawings, in which:

fig. 1 represents a spectrum of light that can be emitted by an emitter with a white light-emitting diode; fig. 2 represents an example of communication signals;

fig. 3 illustrates the light intensity aspect of a first and a second radiation controlled by a signal representing a communication signal;

fig. 4 represents a lighting device according to an embodiment of the invention;

figs. 5A, 5B and 5C represent signals in a lighting device according to an embodiment of the invention without compensation, figs. 6A, 6B and 6C represent signals in a lighting device according to an embodiment of the invention with compensation;

fig. 7 represents a lighting device according to an embodiment of the invention that also includes diodes that emit colored lights;

fig. 8 represents a diagram of a control circuit of a lighting device according to an embodiment of the invention;

fig. 9 represents a modeling scheme of the functions of a diode that emits white light;

fig. 10 represents a first compensation scheme of a lighting device according to an embodiment of the invention;

fig. 11 represents a second compensation scheme of a lighting device according to an embodiment of the invention;

fig. 12 represents a regulation scheme of a lighting device according to an embodiment of the invention;

fig. 13 represents an installation comprising an apparatus and a device according to an embodiment of the invention,

ES 2 289 348 T3 FIG. 14 represents signals that can be emitted by a device according to an embodiment of the invention,

Detailed description of preferred embodiments

Figure 1 shows a spectrum of light that can be emitted by a white light electroluminescent diode usable in a device according to the invention. In such a diode, a first radiation is emitted in blue or ultraviolet, for example centered at a wavelength of 460 nanometers. A second radiation is re-emitted by a fluorescent layer, mainly phosphorous, excited by the first radiation. The second radiation is, for example, in the greens or yellows, for example centered at 550 nanometers, the mixture of these two radiations producing a white light usable for illumination.

Figure 2 shows an example of a communication signal frame that can modulate a first radiation emitted by white light-emitting diodes. The first radiation 1 has a fast response time and allows data to be transmitted at a high flow rate.

In Figure 3, a first radiation 1 represented by a curve 4 has a fast response and a second radiation represented by a curve 5 follows the second radiation with a slower response. If a communication signal 3 varies little as in a first part 6 of figure 3, the second radiation 2 can reach a sufficient value and not disturb the white light too much. In the case that the variation is rapid, as in a second part 7 of the curves of figure 3, the first radiation has its maximum value but the second radiation cannot reach its normal illumination value. In part 7, the brightness of the device decreases and the color rendering is insufficient, as a component of white light is greatly diminished. On the other hand, the slow reaction of the second radiation runs the risk of disturbing radiation sensors intended to receive optical communication signals.

In a lighting device 8 according to an embodiment of the invention represented in FIG. 4, light emitters 10 with an electroluminescent diode for emitting white light 9 are connected to an electronic control circuit 11. A communication circuit 12 it is connected to the control circuit to provide communication signals 13 and to a communication line 14 to receive signals to be transmitted. The electronic control circuit 11 is connected to a power line 15 to receive an electrical energy. When powered by the control circuit, the light emitters 10 produce an initial radiation 1 and a secondary radiation 2 resulting from the excitation of at least one layer 16 of material that reacts to said initial radiation. Thus, the control circuit controls the lighting and controls the supply of the light emitters 10 with an electroluminescent diode to emit a light signal 17 for modulation of said initial radiation 1 as a function of a communication signal 13 provided by the first means of communication 12. Said modulation light signal 17 is intended to be received by a light signal receiver 18 sensitive to the initial radiation 1.

The receiver 18 includes a sensor 19 sensitive to the initial radiation connected to a treatment circuit 20 to process reception signals 21. An optical filter 22 is arranged in front of the sensor 19 to pass a light signal corresponding to an initial radiation 1 and reject secondary radiation 2.

Advantageously, the treatment circuit 20 includes an electronic filter 28 to reduce or suppress a continuous component of a signal that represents an optical signal received by the reception sensor 19. An output signal 98 from the processing circuit is provided to a communication circuit 23 of the receiver which in turn provides signals 24 usable by a function module 25 of the receiver.

The control circuit 11 preferably includes an input for receiving signals 26 provided by a light collector 27. Thus, the circuit 11 can dynamically regulate the light intensity, the color rendering and the color temperature as a function of the light received by the getter. This type of servomechanism allows taking into account the light produced but also the ambient light that may exist in a lighted room. Said sensor can be of the photodiode or color sensor type. In that case, the signal 26 will comprise three signals representing three colors, for example red, green and blue.

Figures 5A to 5C show signals in an uncompensated device. A curve 30 of figure 5A illustrates a communication signal 13, a curve 31 of figure 5B illustrates an optical signal produced by initial radiation 1 and a curve 32 illustrates the appearance of a secondary radiation 2. Initial radiation 1 will be received and used for communication. Secondary radiation is used in combination with the initial radiation to produce white light. In the case of Figures 5A to 5C, communication is done quickly but the color rendering can still be disturbed.

In an advantageous embodiment, the control circuit 11 controls the light emitters 10 with an electroluminescent diode to emit a light signal of said initial radiation by superimposing a continuous component and a modulation signal representing a communication signal.

Figures 6A to 6C show signals in a compensated device. A curve 33 of figure 6A illustrates a communication or control signal 13 comprising a continuous component 34 and a modulated part 35, a curve 36 of figure 6B illustrates an optical signal produced by initial radiation 1 with a continuous part 37 and one

ES 2 289 348 T3 variable part 38, and a curve 39 illustrates the appearance of a secondary radiation 2. The secondary radiation is much less disturbed and regulation can be done more easily by varying the value of the continuous component 34 or 37. Thus , the brightness, the color rendering and the color temperature are very stable and not very dependent on the communication signal.

To improve the control of color rendering and color temperature, a device according to an embodiment of the invention, shown in FIG. 7, comprises emitters 40 of red light 41 with light-emitting diodes and emitters 42 of blue light 43 with light-emitting diodes controlled by control circuit 11.

Figure 8 represents a block diagram of a control circuit 11. In said diagram, a power circuit connected to line 15 feeds the light emitters 10, 40 and 42 through the power electronic circuits, respectively 46 , 47 and 48.

A regulation control circuit 49 receives communication signals 13 and controls the power electronic circuits as a function of values ​​represented by said signals. Current sensors 50, 51 and 52 provide the circuit 49 with signals representing currents that circulate in the light emitters, 10, 40 and 42 respectively. The control and regulation are preferably carried out as a function of parameters 53 provided to the circuit 49. For example, the parameters can be recorded in a memory circuit.

A light collector 27 is connected to circuit 49 to allow efficient regulation of light intensity, color rendering index and / or color temperature. Other sensors 54 can provide control signals 55 to circuit 49. For example, sensor 54 can be a presence detector that allows activating the on or off depending on the presence of a person in a detection zone. The arrangement of the sensor can depend on the use, for example the sensor can be arranged close to the lighting device or moved to a more appropriate place. The sensor can also be arranged on a work table or on a desk. In that case, it will be advantageously connected to the control device by means of a wireless connection, mainly by radio or infrared connection.

Thus, control signals 60, 61 and 62 applied by circuit 49 to power electronic circuits 46, 47 and 48 respectively can depend on various signals or events.

The diagram in figure 9 shows a functional modeling of an electro-luminescent diode that emits white light. A block 70 represents the generator of the initial radiation 1 leaving the optical emitter and a block 71 represents a generator of secondary radiation 2 produced by a fluorescent layer of phosphors. The resulting white light 9 is the combination of radiation 1 and 2.

In a compensation device, the value of the continuous component is adjusted to maintain substantially constant light characteristics. Figure 10 shows a regulation system that makes it possible to provide a control signal 60 to white light emitters subjected to a signal 13 representing a communication signal. Thus, a detection and correction module 72 receives signal 13 and provides a continuous component signal 73 to an operator 74. The operator 74 combines the signal 13 and the signal 73 to provide the control signal 60 of the circuit 46. The direct component 73 can be determined mainly as a function of the mean value, the effective value, the frequency and / or the cyclic ratio of signal 13.

In a regulation system represented in figure 11, a module 72 handles the correction of the DC component by providing a signal 73 and a module 75 that receives the signal 13 handles the correction of the amplitude of the variable signal by providing a modulation signal 76 whose amplitude varies as a function of the input signal 13. Signals 73 and 76 are applied to an operator 77 that provides a signal 78 comprising a continuous component and a variable communication signal corrected as a function of input signal 13.

Signal 78 can be applied to circuit 46 while control signal 60. However, the correction can be completed by a color correction module 79 that receives signal 13 and provides a signal 80 to correct for color rendering and / or the color temperature. Signal 80 is combined with signal 78 on an operator 81 to provide control signal 60. Module 79 can also control blue or red light diodes by providing control signals 61 and 62.

Figure 12 shows a regulation system that also regulates as a function of currents circulating in the light emitters. Thus, a regulation module 85 receives a communication signal 13 and a signal 86 representing a current flowing in electroluminescent diodes of white light provided by the sensor 50. The module 85 regulates and provides a signal 87 that includes a continuous component and a variable part that depend on the signal 13 and the current signal 86. A chromatic correction module 88 receives a signal 26 from a light collector 27 or color, and signals 89 and 90 provided by current sensors 51 and 52 respectively. The module 88 performs color correction based on signals 26, 89 and 90 and provides a correction signal 91 to correct the control of the white light emitters and signals 61 and 62 to control the red and blue light emitters. An operator 92 combines signals 87 and 91 to provide a white light emitter control signal 60. Advantageously, this type of device allows a very efficient compensation of the light intensity, the color rendering index and the color temperature.

ES 2 289 348 T3

Figure 13 shows an installation that includes a lighting device 8 according to an embodiment of the invention connected to a power supply line 15 and an apparatus 95 connected to a receiver 18 that includes a sensor sensitive to the initial radiation 1. Said Receiver 18 may also be integrated into a receiver 96 to receive communication light signals. The electrical devices can be mainly computers, multimedia devices and portable devices, in particular video or audio devices.

Figure 14 shows signals that can also be used in lighting devices in which the variation and adjustment of the brightness is carried out by pulse width modulation or by variation of the diodes' ignition cycle. Thus, the DC component 37 can be modulated at a low frequency to control the intensity of the illumination and the variable component 38 representing the communication signal to be radiated is superimposed on the signal 37.

In the devices described above, the light emitters are represented in direct illumination. However, they can advantageously comprise an optical device for distributing, diffusing and / or mixing light or color to improve the quality of the light. Furthermore, the light emitters can be numerous and arranged in the form of a matrix and / or made up of high-power emitters arranged on the periphery of a distribution device.

References cited in description

This list of references cited by the applicant is only intended to serve as an aid to the reader and is not part of the European patent document. Although great care has been taken in its design, the absence of errors cannot be guaranteed and the OEB declines all responsibility in this regard.

Patent documents cited in the description • US20020048177A [0003].