Matrix light source for a motor vehicle

Abstract

The invention relates to a matrix light source comprising a plurality of primary light sources with light emitting semiconductor elements and a common substrate in contact with an integrated circuit. The integrated circuit is configured to delay the start of the primary light sources for a predetermined period of time upon receiving a start command.

Description

Technical Field

[0001] This invention relates to a matrix light source based on electroluminescent semiconductor elements, particularly a matrix light source for motor vehicles. Specifically, this invention relates to a matrix light source that does not exhibit current peaks in terms of power consumption. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor electronic component that emits light when an electric current flows through it. In the automotive industry, LED technology is increasingly being used in numerous light signal solutions. LEDs are used to provide lighting functions such as daytime running lights and signal lights. The brightness emitted by an LED generally depends on the intensity of the current flowing through it. Among other things, LEDs are characterized by a current intensity threshold. This maximum forward current typically decreases as temperature increases. Similarly, when an LED emits light, a voltage drop equal to its forward voltage or nominal voltage is observed at its terminals.

[0003] The practicality of LED matrix arrays, which include a large number of primary electroluminescent light sources, is advantageous in many application areas, particularly in the lighting and signaling of motor vehicles. LED matrix arrays can, for example, be formed into beams that facilitate lighting functions such as headlights or daytime running lights. Furthermore, a single matrix array can be used to produce a variety of different lighting functions, thereby reducing the physical volume within the limited space of a motor vehicle headlight.

[0004] As is well known, matrix light sources, or equivalent pixelated light sources, are controlled by a control unit that is physically located away from the light source but electrically connected to it. The primary light sources, or the pixels that constitute the matrix light source, extend in a very small size, each approximately 50 μm to 200 μm, and each primary light source or pixel consumes only a low-intensity current of about 10 mA when activated. However, when all the primary light sources of the matrix light source must be activated simultaneously, the matrix light source consumes a high-intensity total current peak: the current consumed by the primary light sources multiplied by the number of pixels. For a matrix light source with 256 pixels, a consumption peak of approximately 2.5 A can be observed. This value obviously becomes higher as the number of pixels and their respective current consumption increase. Such current peaks cause electromagnetic radiation, which can easily cause electromagnetic interference to other electronic components, potentially degrading their performance. This phenomenon is exacerbated in the field of light signals in motor vehicles, where multiple electronic components are located within a limited volume for housing the vehicle's headlights. Summary of the Invention

[0005] One object of the present invention is to overcome at least one of the problems of the prior art. More specifically, one object of the present invention is to provide a matrix light source or pixelated light source in which the current consumption of the matrix light source or pixelated light source is reduced when the pixels of the matrix light source or pixelated light source are activated.

[0006] According to a first aspect of the invention, a matrix light source is provided, comprising an integrated circuit and a matrix array of primary light sources based on electroluminescent semiconductor elements. Notably, the integrated circuit is in contact with the matrix array, and the integrated circuit includes a delay unit for each primary light source in at least one set of primary light sources, the delay unit being configured to delay the activation of the primary light source for a predetermined time period after receiving an activation command for the set of primary light sources.

[0007] According to another aspect of the invention, an integrated circuit for a matrix light source is provided. The integrated circuit is intended to make mechanical and electrical contact with a matrix array of primary light sources of the matrix light source. Notably, the integrated circuit includes a delay unit for each primary light source in at least one set of primary light sources, the delay unit being configured to delay the activation of the primary light source for a predetermined time period after receiving an activation command for the set of primary light sources.

[0008] Preferably, the matrix array of the primary light source may include a common substrate supporting the primary light source. Preferably, the common substrate of the matrix array may contain SiC.

[0009] Preferably, the integrated circuit may include a Si substrate. Preferably, the integrated circuit is soldered or bonded to a matrix array of the primary light source, for example, soldered or bonded to a common substrate supporting the primary light source. Preferably, the integrated circuit is soldered or bonded to the lower surface of the common substrate, which is opposite to the surface including the primary light source. Preferably, the integrated circuit is mechanically contacted with the common substrate, for example by a fastening device, and is electrically contacted with the common substrate, which has an electrical connection region on its lower surface.

[0010] The delay unit of each primary light source in the set is functionally connected to the delay unit of another primary light source in the set, such that the delay of the second primary light source begins to disappear immediately only when the delay of the first primary light source has disappeared.

[0011] Preferably, the delay unit of each primary light source may include a trigger circuit for sending a trigger signal to the light source connected to the trigger circuit after the delay of the light source itself has expired.

[0012] Preferably, the delay of each primary light source in the set can be consistent.

[0013] Preferably, the delay unit may include a storage element for recording delay values.

[0014] Preferably, the delay units of the primary light sources in the set can be functionally sequentially connected to form a chain.

[0015] Preferably, the light source set may include all the primary light sources of the matrix light source.

[0016] Preferably, the delay unit may include a delay line.

[0017] Preferably, the delay lines associated with all primary light sources of the primary light source are timed by the same clock signal.

[0018] According to another aspect of the present invention, a lighting module for a motor vehicle is provided. The lighting module includes a matrix light source and circuitry for driving power to the light source. Notably, the matrix light source in the lighting module is a matrix light source according to one aspect of the present invention.

[0019] A pixelated light source, or equivalently a matrix light source, preferably includes at least one matrix array of electroluminescent elements (i.e., primary light sources), also referred to as a monolithic array, wherein the electroluminescent elements are arranged in at least two columns by at least two rows. Preferably, the electroluminescent source includes at least one monolithic matrix array of electroluminescent elements, also referred to as a monolithic matrix array.

[0020] In a monolithic matrix array, electroluminescent elements are grown from a common substrate and electrically connected so that they can be selectively activated, individually activated, or activated by a subset of electroluminescent elements. Thus, each electroluminescent element or group of electroluminescent elements can form one of the primary emitters of the pixelated light source, which emits light when the material of one or more primary emitters is powered.

[0021] Various arrangements of electroluminescent elements can satisfy this definition of a monolithic matrix array, provided that one of the major elongation dimensions of the electroluminescent elements is substantially perpendicular to the common substrate, and the spacing between primary emitters formed by electrically combining one or more electroluminescent elements is smaller than the spacing imposed in known arrangements of flat square chips soldered to printed circuit boards.

[0022] The substrate can be made primarily of semiconductor materials. The substrate may include one or more other materials, such as non-semiconductor materials. These submillimeter-sized electroluminescent elements are arranged, for example, as rods protruding from the substrate to form hexagonal cross-sections. The electroluminescent rods originate from a first surface of the substrate. In this case, each electroluminescent rod formed using gallium nitride (GaN) can extend vertically or substantially vertically from the substrate, which is made of silicon and other materials (e.g., silicon carbide), and is used without departing from the context of the invention. For example, the electroluminescent rods can be made of an alloy of aluminum nitride and gallium nitride (AlGaN), or an alloy of aluminum, indium, and gallium phosphide (AlInGaP). Each electroluminescent rod extends along an extension axis defining its height, and the base of each rod is disposed in a plane on the upper surface of the substrate.

[0023] Advantageously, the electroluminescent rods of an identical monolithic matrix array have the same shape and size. Each electroluminescent rod is defined by an end face and circumferential walls extending along the rod's extension axis. When the electroluminescent rod is doped and polarized, the light generated at the output of the semiconductor source is emitted primarily from the circumferential walls; it is understood that light can also exit from the end faces. As a result, each electroluminescent rod acts as a single light-emitting diode, and the brightness of the light source is increased firstly by the density of the existing electroluminescent rods, and secondly by the size of the light-emitting surface defined by the circumferential walls, and thus extends over the entire circumference and height of the rod. The height of the rod can be between 2 μm and 10 μm, preferably 8 μm. The maximum dimension of the end face of the rod is less than 2 μm, preferably less than or equal to 1 μm.

[0024] Understandably, when forming electroluminescent rods, the height can be changed from one region of the pixelated light source to another, such that as the average height of the rods forming the pixelated light source increases, the brightness of the corresponding region can be improved. Therefore, a set of electroluminescent rods can have one or more different heights than another set of electroluminescent rods, both sets forming the same semiconductor light source comprising sub-millimeter-sized electroluminescent rods. The shape of the electroluminescent rods can also vary from one monolithic matrix array to another, particularly in the shape of the rod's cross-section and end faces. The rods have a generally cylindrical shape, and the rods can particularly have a polygonal cross-section, and more particularly a hexagonal cross-section. Understandably, it is important to be able to emit light through the circumferential walls, which have a polygonal or circular shape.

[0025] In addition, the end face can have a generally flat shape that is perpendicular to the circumferential wall, such that the end face extends substantially parallel to the upper surface of the substrate, or the end face can have a shape that is curved or pointed at its center, thereby increasing the direction of light emitted from the end face.

[0026] Preferably, the electroluminescent rods can be arranged in a two-dimensional matrix. This arrangement allows the rods to be arranged in a staggered pattern. Generally, the rods are arranged on the substrate at regular intervals, and in each dimension of the matrix array, the distance between two adjacent electroluminescent rods should be at least 2 μm, preferably between 3 μm and 10 μm, so that light emitted through the circumferential walls of each rod can exit from the matrix array of electroluminescent rods. Furthermore, it is specified that these separation distances, measured between the two extension axes of adjacent rods, are no greater than 100 μm.

[0027] As an alternative, a monolithic matrix array may comprise electroluminescent elements formed from layers of epitaxial electroluminescent elements located on a single substrate, particularly a first n-doped GaN layer and a second p-doped GaN layer, the single substrate being, for example, made of silicon carbide, and the monolithic matrix array being cut (by grinding and / or ablation) to form multiple primary light emitters, each originating from a single, identical substrate. The result of this design is that multiple electroluminescent blocks all originate from a single, identical substrate and are electrically connected to each other, thus enabling them to be selectively activated.

[0028] In an exemplary embodiment according to another implementation, the thickness of the substrate of the monolithic matrix array can be between 5 μm and 800 μm, particularly equal to 200 μm; each block can have a length and width, each length and width being between 50 μm and 500 μm, preferably between 100 μm and 200 μm. In a variation, the length and width are equal. The height of each block is less than 500 μm, preferably less than 300 μm. Finally, the emitting surface of each block can be formed on the side opposite to the epitaxial layer by the substrate. There is a separation distance between the two primary emitters. The distance between each successive primary emitter can be less than 1 mm, particularly less than 500 μm, and preferably less than 200 μm.

[0029] As an alternative, the monolithic matrix array has both electroluminescent rods extending from one and the same substrate as described above, and electroluminescent blocks obtained by cutting electroluminescent layers superimposed on one and the same substrate. The monolithic matrix array may also include a layer of polymer material in which electroluminescent elements are at least partially embedded. Thus, the layer may extend over the entire extent of the substrate or only around a given group of electroluminescent elements. In particular, the polymer material may be a silicone-based polymer material forming a protective layer that protects the electroluminescent elements without impairing light diffusion. Furthermore, it is possible to integrally fabricate a wavelength conversion device (e.g., a light emitter) into the polymer material layer, which is capable of absorbing at least some of the rays emitted by one of the elements and converting at least some of the absorbed excitation light into emitted light with a wavelength different from that of the excitation light. It may be specified indiscriminately that the light emitter is embedded in the polymer material block or disposed on the surface of the polymer material layer.

[0030] The pixelated light source may also include a coating of reflective material used to deflect light to the emitting surface of the light source.

[0031] Submillimeter-sized electroluminescent elements define a given emission surface in a plane substantially parallel to the substrate. It will be understood that the shape of this emission surface is defined by the number and arrangement of the electroluminescent elements forming it. Therefore, a generally rectangular shape can be defined for the emission surface, and it should be understood that the emission surface can vary and take any shape without departing from the context of the invention.

[0032] By using the measures proposed in this invention, a matrix light source or pixelated light source can be provided in which the current consumption of the matrix light source or pixelated light source is reduced when its pixels are activated. By potentially delaying the activation of each pixel individually, this invention can smooth out the current intensity peaks that occur in known solutions when activating the matrix light source over time. This smoothing of current consumption leads to a reduction in electromagnetic radiation, thereby reducing the risk of electromagnetic interference from other electronic components located physically near the matrix light source. Since the delay for each pixel remains very short, the overall effect of the delay is invisible or almost imperceptible. Attached Figure Description

[0033] Other features and advantages of the invention will be better understood with the aid of examples and accompanying drawings, in which:

[0034] Figure 1 A matrix light source according to a preferred embodiment of the present invention is schematically shown;

[0035] Figure 2 A matrix light source according to a preferred embodiment of the present invention is schematically shown;

[0036] Figure 3 A timing diagram is shown, indicating the startup time of each pixel after receiving a startup command from a matrix light source according to the prior art, and the startup time of each pixel after receiving a startup command from a matrix light source according to a preferred embodiment of the present invention.

[0037] Figure 4 Details of a matrix light source according to a preferred embodiment of the present invention are schematically shown;

[0038] Figure 5 A timing diagram illustrating the start-up time of each pixel after the matrix light source receives a start-up command, according to a preferred embodiment of the present invention, is shown. Detailed Implementation

[0039] Unless otherwise stated, the technical features described in detail for a given embodiment may be combined with the technical features described in the context of other embodiments described by way of example, and there is no limitation thereto. In various embodiments of the invention, similar reference numerals will be used to describe similar concepts. For example, reference numerals 100, 200, and 300 denote three embodiments of a matrix light source according to the invention.

[0040] Figure 1 The figure illustrates a pixelated light source or matrix light source 100 according to a preferred embodiment of the present invention. The matrix light source 100 includes a plurality of primary light sources 110 based on electroluminescent semiconductor elements and a common substrate (not shown) that is mechanically and electrically contacted with and functionally connected to an integrated circuit 120. The primary light sources are typically light-emitting diodes (LEDs).

[0041] Preferably, the matrix light source 100 includes a monolithic matrix array component, in which the semiconductor layer of the primary light source 110 is disposed, for example, on the common substrate. Preferably, the matrix array of the primary light source 110 includes parallel components having multiple branches, each branch including an electroluminescent semiconductor light source 110.

[0042] By way of example and not limitation, the matrix array of the primary light source includes a first conductive layer deposited on an electrically insulating substrate, extending along the thickness of the substrate and starting from the end opposite to the position of the primary light source 110. Following this first conductive layer is an n-doped semiconductor layer with a thickness between 0.1 µm and 2 µm. This thickness is much smaller than that of known light-emitting diodes (LEDs), for which the corresponding layer has a thickness of approximately 1-2 µm. The next layer is an active quantum well layer with a thickness of approximately 30 nm, followed by an electron blocking layer, and finally a p-doped semiconductor layer with a thickness of approximately 300 nm. Preferably, the first layer is an (Al)GaN:Si layer, the second layer is an n-GaN:Si layer, and the active layer includes quantum wells made of InGaN alternating with barriers made of GaN. The blocking layer is preferably made of AlGaN:Mg, and the p-doped layer is preferably made of p-GaN:Mg. The n-doped gallium nitride has a resistivity of 0.0005 Ohm / cm, while the p-doped gallium nitride has a resistivity of 1 Ohm / cm. Because the n-doped layer is not as thick as known LEDs and requires a shorter deposition time, the thickness of these layers allows for a significant increase in the internal series resistance of the primary light source, while simultaneously reducing the fabrication time. For example, for a standard LED configuration with a 2 µm n-layer, MOCVD deposition typically takes 5 hours; if the thickness of the n-layer is reduced to 0.2 µm, this time can be reduced by 50%.

[0043] To obtain a primary light source 110 with a semiconductor layer of uniform thickness, preferably, the monolithic component 100 is manufactured by uniformly and homogeneously depositing the layer on at least a portion of the surface of a substrate to cover the substrate. These layers are deposited, for example, using a metal oxide chemical vapor deposition (MOCVD) method. Methods and reactors for achieving these are known, for example, from patent documents WO 2010 / 072380 A1 or WO 01 / 46498 A1, which are used to deposit semiconductor layers on a substrate. Therefore, details regarding their implementation will not be described further in the context of this invention. The resulting layer is then pixelated. By way of example, and not limitation, the layer is removed using known photolithography methods and by subsequently etching at locations corresponding to the spaces between the primary light sources 110 on the substrate. Thus, it is possible to produce groups of tens, hundreds, or thousands of pixels 110 on the substrate of the matrix light source 100, wherein the surface area of ​​each individual pixel is less than 1 square millimeter, and the total surface area is greater than 2 square millimeters, the semiconductor layer has a uniform thickness, and therefore has a uniform and high internal series resistance. Generally, the smaller the size of each LED pixel, the greater the increase in the series resistance of that LED pixel, and the more capable the pixel is of being driven by a voltage source. Alternatively, a substrate comprising an epitaxial layer covering at least a portion of the surface of a substrate can be sawn or divided into primary light sources, each of which has similar characteristics in terms of its internal series resistance.

[0044] The present invention also relates to a type of primary light source based on semiconductor elements that includes semiconductor layers with other configurations. In particular, the substrate, the semiconductor material of the layers, the arrangement of the layers, the thickness of the layers, and any vias between the layers may differ from the example just described.

[0045] Preferably, the integrated circuit 120 is soldered to the lower surface of a common substrate housing the primary light sources to establish mechanical and electrical contact with the substrate and the primary light sources. The integrated circuit also includes a delay unit 130 for at least one primary light source 110, but preferably for all primary light sources 110, configured such that the activation of the primary light source is delayed for a predetermined period of time after receiving a start command 12, typically generated by a control unit external to the matrix light source 100. The delay unit 130 is formed, for example, by electronic circuitry forming delay lines. Such electronic circuitry is well known in the art and its operation will not be described in detail in the context of this invention. The delay generated for each primary light source 110 is preferably different, such that the control signal 12, intended to simultaneously activate all primary light sources 110 of the matrix light source 100, is delayed differently for each of the primary light sources 110, or at least for a separate set of the primary light sources. Since the activation of the primary light source may be delayed individually for each primary light source, this avoids a single maximum peak in the power consumption of the matrix light source 100 when the control signal 12 is active.

[0046] The use of an integrated circuit 120 that has mechanical and electrical contact with a substrate (on which a primary light source resides) eliminates the need for wired connections, the number of which will be at least equal to the number of pixels of the matrix light source.

[0047] Depending on the matrix light source, it can be driven by voltage or current via a power supply driving circuit. Such circuits are known in the art and their operation will not be described in detail in the context of this invention. They involve at least one converter circuit capable of converting an input voltage / current supplied, for example, by a voltage / current source (such as a battery) within a motor vehicle, into an output voltage / current with an intensity suitable for powering the matrix light source. When the matrix light source is voltage driven, the driving of each primary light source (or equivalently, each pixel) only requires control such as… Figure 1 The switching device 132 is schematically shown. By controlling the state of the device 132, the primary light source 110 can be selectively connected to the voltage source 10. The switching device is formed, for example, by a MOSFET field-effect transistor, and preferably, the switching device is characterized by a low voltage drop between the drain and source terminals of the switching device, and said voltage drop is controlled by a control signal 12 delayed by the delay unit 130.

[0048] Preferably, when manufacturing the monolithic component 100, not only the switching element 132 but also the power supply circuit can be integrated into the substrate 120.

[0049] Figure 2The figure illustrates a pixelated light source or matrix light source 200 according to a preferred embodiment of the present invention. The matrix light source 200 includes a plurality of primary light sources 210 based on electroluminescent semiconductor elements and a common substrate (not shown) that is in contact with and functionally connected to an integrated circuit 220. The primary light sources are typically light-emitting diodes (LEDs).

[0050] Preferably, the matrix light source 200 is a monolithic component in which the semiconductor layer of the primary light source 210 is disposed on a common substrate. Preferably, the matrix light source 200 includes a parallel assembly with multiple branches, each branch including an electroluminescent semiconductor light source 210.

[0051] Integrated circuit 220 also includes a delay unit 230 for at least one primary light source 210, but preferably for all primary light sources 210, which is configured to delay the activation of the primary light source for a predetermined period of time after receiving a start command 12, which is preferably binary and typically generated by a control unit external to matrix light source 200. The delay unit 230 is formed, for example, by electronic circuitry forming delay lines.

[0052] Depending on the matrix light source, it can be driven by voltage or current via a power supply drive circuit. Controlling the switching device 232 allows for selective power supply to the primary light source 210. Figure 2In the illustrated embodiment, this control is performed by a delay unit 230, which reproduces a delayed version of the control signal 12. The delay units 230 associated with each primary light source 210 are connected to each other via electrical connectors 231, preferably in a chain-like manner. When the delay for the (left) primary light source has elapsed, the (left) delay unit 230 controls the switching device 232 to supply power to the primary light source 210. Simultaneously, the (left) delay unit 230 sends an "enable" trigger signal, for example a binary signal, to the (right) co-source delay unit 230 associated with the (right) primary light source 210. Only upon receiving this "enable" signal from the (left) delay unit, the (right) delay unit 230 immediately begins counting down its predetermined delay. When the delay time for the (right) primary light source has elapsed, the (right) delay unit 230 controls the switching device 232 to supply power to the (right) primary light source 210. Even if the two delay units are configured to implement inverses of similar durations, this means that the effective delay for the two primary light sources is different because the delay between the connected delay units is cumulative. For the (right) delay unit 230 in the given example, the effective delay is twice that of the (left) delay unit 230. Preferably, the delay units are timed by a clock signal of a rule not shown. Since the startup of the primary light sources, which form part of the chain connecting the respective delay units of the primary light sources, is delayed separately for each primary light source, this makes it possible to avoid a single maximum peak in the power consumption of the matrix light source 200 when the control signal 12 is active.

[0053] Figure 3 It shows the method for... Figure 2 The evolution of the binary clock signal, which is the timing rule of the delay unit 230, over time is shown. Below the clock signal, the startup times of three pixels using a matrix light source known in the prior art are illustrated: pixels indicated by n-1, n, and n+1 are simultaneously powered, corresponding to the receipt of startup command 12. Figure 3 At the bottom, the startup time of three pixels using a matrix light source according to an embodiment of the accompanying drawings is shown. The delay units of each of the pixels n-1, n, and n+1 are functionally interconnected such that the delay of pixel n begins to vanish immediately only when the delay of pixel n-1 has vanished, and so on. In this case, each delay unit implements the same delay of one clock cycle.

[0054] In the example shown, the delay units are synchronized with respect to the rising edge of the clock signal, but this does not limit the invention. Specifically, the delay units may also be synchronized with respect to the rising edge of the clock signal or with respect to a predetermined point in the period of the clock signal.

[0055] Figure 4 The figure illustrates details of an integrated circuit for a pixelated light source or matrix light source 300 according to a preferred embodiment of the present invention. The matrix light source 300 includes a plurality of primary light sources 310 based on electroluminescent semiconductor elements and a common substrate (not shown) that contacts and is functionally connected to the integrated circuit. The primary light sources are typically light-emitting diodes (LEDs).

[0056] The integrated circuit also includes a delay unit 330 for at least one primary light source, but preferably for all primary light sources. This delay unit 330 is configured to delay the activation of the primary light source for a predetermined time period after receiving a start command 12, which is preferably binary and typically generated by a control unit external to the matrix light source 300. The delay units 30 of the primary light sources are interconnected, as if referring to... Figure 2 As in the described embodiments, timing is performed by a common, regular binary clock signal 14.

[0057] The delay unit 330 includes, for example, a logic unit 333 formed by a comparison circuit. The logic unit 333 compares the control signal 12 with a state signal generated by the countdown unit 334. For example, the state signal is zero when the delay has not yet expired; and it switches to a non-zero value when the delay has expired. If both signals have non-zero values, the resulting trigger signal 331 is non-zero. It then relays the control signal to the (right-hand) delay unit 330 to trigger the corresponding delay there. The countdown unit 334 includes, for example, a countdown circuit configured to read the value of the delay to be counted from a memory element or register 336 of the integrated circuit. When the countdown ends, the delay unit 330 controls the device 332 to supply power to the associated light source 310. Using the memory element 336 to record the respective delay of each primary light source allows for increased flexibility. Different delays can be recorded for each primary light source, and the recorded values ​​can be modified over time by writing instructions to the respective memory elements 336. The effective delay of each light source obviously also depends on the frequency of clock signal 14. It goes without saying that integrated circuits can include other electronic circuits, which in... Figure 4 The area is indicated by shaded regions. In particular, this could be a circuit that performs diagnostic functions on the operation of a primary light source.

[0058] Figure 5 It shows the method for... Figure 3The evolution of the binary clock signal, which is timed by the delay unit 430, is shown over time. Below the clock signal, the startup time of pixel n-1 using a matrix light source known from the prior art is shown: when startup command 12 is received, the indicated pixel is powered on. Below, the use of a matrix light source according to... Figure 4 The implementation of the matrix light source in this embodiment describes the start-up time of two pixels. The delay units of each pixel in pixel n and pixel n+1 are functionally connected to each other such that the delay of pixel n+1 begins to vanish immediately only when the delay of pixel n has vanished. In this case, the delay unit of pixel n implements a four-clock-cycle delay, while the delay unit of pixel n+1 implements a two-clock-cycle delay, and the delay of pixel n+1 begins to vanish immediately only when the delay of pixel n has vanished. At the bottom of the figure, it can be seen that the effective delay can also be modified by changing the frequency of the clock signal. In the example shown, the signal frequency is doubled compared to the example shown in the middle of the figure.

[0059] The scope of protection is defined by the claims.

Claims

1. A matrix light source (100, 200, 300), said matrix light source comprising a matrix array of integrated circuits (120, 220) and primary light sources (110, 210, 310) based on electroluminescent semiconductor elements, in, The integrated circuit is in contact with the matrix array and includes a delay unit (130, 230, 330) for each primary light source in at least one set of primary light sources, the delay unit being configured to delay the activation of the primary light source (110, 210, 310) for a predetermined time period after receiving a start command (12). The delay unit (230, 330) of each primary light source in the primary light source set is functionally connected to the delay unit of another primary light source in the primary light source set. This arrangement is such that the delay of the second primary light source immediately begins to disappear only when the delay of the first primary light source has disappeared and the delay unit of the first primary light source sends a trigger signal to the delay unit of the second primary light source.

2. The light source according to claim 2, characterized in that, The delay unit (230, 330) of each primary light source includes a trigger circuit for sending a trigger signal to the light source connected to the trigger circuit after the delay of the light source itself has elapsed.

3. The light source according to claim 1 or 2, characterized in that, The delay of each primary light source in the set of primary light sources is consistent.

4. The light source according to claim 1 or 2, characterized in that, The delay unit (330) includes a storage element (336) for recording delay values.

5. The light source according to claim 1 or 2, characterized in that, The delay units of the primary light sources in the primary light source set are functionally connected sequentially to form a chain.

6. The light source according to claim 1 or 2, characterized in that, The light source set includes all of the primary light sources of the matrix light source.

7. The light source according to claim 1 or 2, characterized in that, The delay unit includes a delay line.

8. The light source according to claim 7, characterized in that, The delay lines associated with all of the primary light sources are timed by the same clock signal.

9. A lighting module for a motor vehicle, the lighting module comprising a matrix light source and circuitry for driving power to the light source, characterized in that, The matrix light source is a matrix light source according to any one of claims 1 to 8.

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