Wiring of high-resolution light sources

Abstract

The present invention relates in particular to a ground vehicle lighting module, the lighting module comprising: an electroluminescent source including at least one electroluminescent element; an electronic device designed to control the electroluminescent element; and an inserter electrically connected to the electroluminescent source and the electronic device.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201780057004.5 (filed on August 4, 2017; invention title: wiring of high resolution light source). Technical Field

[0002] This invention relates to the field of lighting modules for ground vehicles; in other words, modules that can be integrated into a vehicle's lighting system, and modules that, when the vehicle is in use, allow light to be projected to illuminate the road or passenger compartment and / or make the vehicle itself more visible. Examples of such lighting systems are marker lights or low beam and / or high beam lights (commonly referred to as "headlights"). Background Technology

[0003] Ground vehicles are equipped with lighting devices such as headlights or taillights, specifically for illumination and / or signal indication. These lighting devices are designed to illuminate the road ahead of the vehicle at night or in conditions of reduced lighting. Lighting devices can also be used to illuminate the passenger compartment of the vehicle. These lighting devices may include one or more lighting modules. Each lighting function may be provided by one or more modules.

[0004] Semiconductor light sources are increasingly being used in lighting modules for ground vehicles. These light sources can include light-emitting diodes (or LEDs), organic light-emitting diodes (or OLEDs), or polymer light-emitting diodes (or PLEDs). Compared to conventional light sources such as filament bulbs, these light sources offer particular advantages in terms of size and lifespan.

[0005] The use of these new light sources offers new prospects for improving the illumination characteristics provided by vehicle lighting devices. In particular, the use of monolithic LED arrays allows for the selection of scene areas to be illuminated with very high precision and at what brightness. A monolithic array comprises hundreds or thousands of LEDs located on the same substrate, separated from each other by channels or pathways. In this monolithic array environment, LEDs are also called pixels. However, each LED is electrically independent of the other LEDs and therefore illuminates itself spontaneously independently of the other LEDs in the array. For this purpose, each LED in the array is individually controlled by electronic circuitry that manages its power supply (circuitry called a "driver"), meaning that the higher the LED density, the greater the number of wires used to power the LEDs.

[0006] To make power routing for the LEDs in an array feasible, a technique known as "stacking" is used, which involves stacking the LED array with circuitry that manages its power (or "driver"). However, several technical constraints limit the feasibility of such stacking. First, heat dissipation is reduced due to the extensive stacking of the LED array with its driver. This is a significant issue because the heat generated by the LEDs causes temperatures to rise within the component, which can degrade the component and / or hinder its optimal use. Furthermore, the driver itself generates heat and can be damaged by the heat generated by the LEDs. Additionally, there are constraints regarding the geometry of the driver, which is typically implemented on an ASIC (Application-Specific Integrated Circuit). In practice, the standardized dimensions of the ASIC must correspond to the dimensions of the array conforming to other standards in order to obtain a lighting module with the smallest possible size. However, current standards do not provide any correspondence between these different dimensions, resulting in excessively large size differences between the driver and the LED array. Summary of the Invention

[0007] For this purpose, a lighting module for a ground vehicle is provided, the lighting module comprising: an electroluminescent source including at least one electroluminescent element; an electronic device designed to control the electroluminescent element; and an inserter electrically connecting the electroluminescent source and the electronic device.

[0008] According to various examples, the lighting element according to the invention may include one or more of the following features combined together:

[0009] - An electroluminescent source and electronic devices are arranged on at least one surface of the inserter;

[0010] - A heat sink is arranged on one side of the inserter;

[0011] - An electroluminescent source and electronic devices are arranged on the first surface of the inserter, and a heat sink is arranged on the second surface of the inserter;

[0012] - The heat sink is arranged against the insert via an intermediate element, the intermediate element comprising at least one of the following: thermal paste, copper layer, adhesive;

[0013] - The inserter includes at least one of inorganic and organic materials;

[0014] Inorganic materials include at least one of the following materials: silicon, glass, and ceramics;

[0015] - The electronic device includes at least one power converter and / or an integrated circuit;

[0016] - Passive electronic components and / or active electronic components;

[0017] - Electronic components are arranged on and / or in the inserter;

[0018] - The inserter includes at least one metal track, the at least one metal track being electrically connected to the at least one electroluminescent element of the electronic device and the electroluminescent source;

[0019] - The electroluminescent source includes at least two electroluminescent elements electrically connected in series, and the inserter includes at least one metal track electrically connected to the electronic device and the at least two electroluminescent elements electrically connected in series;

[0020] - At least one electrical connector, said at least one electrical connector being disposed on the inserter and electrically connected to an electronic device;

[0021] - The electroluminescent source is a monolithic array of light-emitting diodes.

[0022] A lighting device is also provided, particularly preferably for lighting and / or signaling devices for ground vehicles, the lighting device comprising the lighting elements described above. Attached Figure Description

[0023] Various embodiments of the invention will now be described by way of non-limiting example with reference to the accompanying drawings, in which:

[0024] Figure 1 An electronic device according to the prior art is illustrated schematically;

[0025] Figure 2 An example of a lighting element according to the invention is shown schematically; and

[0026] Figure 3 An example of wiring for a monolithic array LED according to the present invention is illustrated schematically. Detailed Implementation

[0027] Figure 1 An example of a lighting element known in the prior art is shown, under the term "stacked ASIC": an LED array is rested on an ASIC circuit to allow it to be powered. The interface between the LED array and the driver is indicated by a shaded line. This interface may include an adhesive to ensure that the LED array remains in contact with the driver.

[0028] Figure 2An example of a lighting element according to the invention is shown. The lighting element may be a ground vehicle lighting module. One or more lighting modules may be configured as a lighting device or may be integrated into a lighting device. The lighting device may be a headlight, a taillight, or a lighting device for a passenger compartment. A ground vehicle is also provided that includes one or more styles of such lighting devices (e.g., for a four-wheeled vehicle, one or more pairs of styles in the front and / or one or more pairs of styles in the rear, or for a two-wheeled or three-wheeled vehicle, one or more styles in the front and / or one or more styles in the rear).

[0029] The lighting element 20 includes at least one electroluminescent source 200, which includes at least one electroluminescent element 202. The electroluminescent source is a solid-state light source that includes at least one electroluminescent element. The electroluminescent element can be, but is not limited to, a light-emitting diode (LED), an organic light-emitting diode (OLED), or a polymer light-emitting diode (PLED). Therefore, the electroluminescent source is a semiconductor light source, and it includes a substrate 204 from which the electroluminescent element extends. The electroluminescent element is more commonly referred to as a pixel. Thus, the lighting element includes at least a plurality of pixels deposited on or extending from a first surface of the substrate 204.

[0030] All electroluminescent elements can be semiconductor elements; in other words, all electroluminescent elements include at least one semiconductor material. Most electroluminescent elements can be made of semiconductor materials. This semiconductor material can be the same as or different from the semiconductor material of the substrate. More commonly, electroluminescent elements can be made entirely of the same one or more materials. Electroluminescent elements can have the same properties, such as substantially the same or similar properties. All electroluminescent elements can be positioned to form a regular pattern, such as a grid.

[0031] The elements are electroluminescent. This means that these elements emit light when the material of an electroluminescent element is powered. Therefore, when an electroluminescent element emits light, a pixel is said to be lit. Electroluminescent elements use electroluminescence to emit light. Electroluminescence is an optical and electrical phenomenon in which a material emits light in response to an electric current flowing through it or in response to a high electric field. This is different from light emission caused by temperature (incandescence) or the action of chemical products (chemiluminescence).

[0032] In the first example, the electroluminescent source is a monolithic electroluminescent source, also known as a monolithic LED array. A monolithic array comprises hundreds or thousands of electroluminescent elements located on the same substrate 204, and preferably on the same face of the substrate, which may be made of, for example, sapphire. The LEDs of the monolithic array are separated from each other by “channels” or “paths.” Thus, a monolithic array is a grid of electroluminescent elements or a pixel grid. Each electroluminescent element in the array is electrically independent of the other electroluminescent elements and emits light or does not emit light independently of the other elements in the array. Each element in the array is individually controlled by an electronic circuit called a “driver.” Alternatively, the electroluminescent elements can be electrically grouped, for example by powering the electroluminescent elements by means of a parallel or series configuration, to reduce the number of elements to be managed. For example, these groups may include two to four electroluminescent elements, a number that allows for a sufficiently pixelated beam of light to be retained. The driver manages the power supply to the monolithic array, which is equivalent to saying that it individually controls the power supply to each electroluminescent element. Therefore, a driver is an electronic device designed to control a monolithic array of electroluminescent elements.

[0033] In the second example, the lighting element includes at least one semiconductor electroluminescent source comprising a substrate 204, which is substantially made of a semiconductor material. Therefore, the term "semiconductor substrate" can be used to refer to the substrate. The substrate may include one or more other materials, such as non-semiconductor materials. The electroluminescent source also includes one or more components of electroluminescent elements extending from a first surface of the substrate. Therefore, the lighting element includes at least a plurality of such elements extending from the first surface of the substrate. Each component consists of several elements extending from a corresponding portion of the first surface of the substrate. Thus, the electroluminescent elements can be distributed within various light-emitting regions. In one example, these regions may be selectively activated regions. The elements may have a general rod shape and are therefore referred to as "rods".

[0034] Similarly, in this second example, the electroluminescent elements can be powered on one side via a substrate (e.g., the substrate forming a cathode) and on the other side via a conductive material layer (e.g., the conductive material layer forming an anode), which electrically connects the electroluminescent elements together. Therefore, the contact between the semiconductor material of each electroluminescent element and the semiconductor material of the substrate can be adapted to be conductive. The conductive material layer can cover the electroluminescent elements. The conductive material layer can also cover every portion of the surface of the substrate from which the electroluminescent elements extend, or cover the entire surface or facet of the substrate from which the components of the electroluminescent elements extend. The conductive material layer can be electrically insulated from the semiconductor material of the substrate by any means. This allows the electroluminescent elements to be powered via the substrate. Therefore, the electroluminescent elements can be powered in a simple manner, in other words, by providing one polarity to the conductive material of the substrate and another polarity to the conductive material layer.

[0035] Similarly, in this second example, the electroluminescent source can be manufactured by a method including at least one step for supplying a substrate, followed by a step of integrally forming a rod with the substrate by growing it from the substrate. A conductive material layer can be formed by a step of depositing a metallic finish (e.g., copper) to provide actuation of the rod. This step may also include forming an aluminum or copper pad on one side of the substrate, the pad being designed for wiring via a line between the source and the actuator components. Wiring via a line (“wire bonding” or “band bonding”) is one of the techniques used to make electrical connections between an electroluminescent source and a device for powering the source. Wiring is simply formed by welding a line (or bridge) between two connecting lugs provided for this purpose on each component. Welding can be performed ultrasonically. The wire can be aluminum, gold, or copper. The wire diameter can be on the order of 20 μm. Wires with rectangular cross-sections can also be used.

[0036] Preferably, the electroluminescent source is a monolithic electroluminescent source, such as the electroluminescent source described in the first example above. A monolithic source is a source with a high density of pixels (or electroluminescent elements). In practice, if the pixel density is greater than or equal to 400 pixels per square centimeter (cm²), then... 2 If the electroluminescent source is a single-chip electroluminescent source, then it can be considered as such. In other words, the distance between the center of the first pixel and the center of the second pixel adjacent to the first pixel is equal to or less than 500 micrometers (μm); this distance is also called the "pixel pitch".

[0037] The lighting element according to the invention includes one (or more) electronic devices 220, which are designed to control the electroluminescent element of the electroluminescent source. Such electronic devices may be, for example, integrated circuits or power converters.

[0038] A power converter is a device for converting power from a vehicle's power system into power suitable for achieving a desired lighting function and potentially providing power suitable for an electroluminescent source to achieve the desired lighting function.

[0039] An integrated circuit, also known as an electronic chip, is an electronic component that reproduces one or more electronic functions, and this electronic component can integrate several types of basic electronic components, for example, in a reduced size (i.e., on a small substrate). This makes the circuit easy to implement.

[0040] Integrated circuits can be, for example, ASICs or ASSPs.

[0041] An ASIC (an abbreviation for "Application-Specific Integrated Circuit") is an integrated circuit developed for at least one specific application (in other words, for a customer). Therefore, an ASIC is a dedicated (microelectronics) integrated circuit. Typically, it combines a large number of unique or custom-designed functions.

[0042] ASSP (an abbreviation for "Application-Specific Standard Product") is an integrated electronic (microelectronic) circuit that combines a large number of functions to meet typically standardized applications. ASIC is designed to meet more specific requirements than ASSP.

[0043] The power supply for the electroluminescent source and thus the electroluminescent element is implemented via an electronic device, which is powered itself by means of, for example, a connector that at least connects it to the power supply. The electronic device then supplies power to the electroluminescent element. Thus, the electronic device is designed to control the electroluminescent element.

[0044] The lighting element also includes an inserter 210, which electrically connects the electroluminescent source 200 and the electronic device 220. The inserter is an electrical interface that allows power to be transmitted along a path between two connectors. In other words, the inserter is a substrate that allows at least two connectors to be connected together. The path of the connection between the two connectors can be achieved by means of conductive tracks. Tracks can be formed on the substrate of the inserter; in other words, they can be formed on the surface of one or more sides of the inserter. Tracks can be formed within the substrate of the inserter; in other words, the tracks are located inside the substrate of the inserter. Tracks can include portions on the substrate and portions within the substrate of the inserter. The inserter can include any given combination of the three types of tracks described above. The track includes at least two connectors located at either end of each end of the track and allowing electrical contact with the connectors of the electroluminescent source and the electronic device. Figure 2In the inserter, a track 230 is formed inside the substrate and includes a first end 232 connected to a connector for the electroluminescent element 202 of the electroluminescent source 200 and a second end 234 connected to a connector for the ASIC 220, so as to realize the driver of the electroluminescent source 200.

[0045] The rails of the inserter are usually made of metal because metal provides good electrical conductivity; for example, the rails are made of copper.

[0046] The inserter includes a substrate that provides electrical insulation between its various tracks. One or more materials constituting the substrate of the inserter may be inorganic and / or organic materials.

[0047] Inorganic materials primarily include, but are not limited to, synthetic and natural glass, enamel, ceramics, and stone. Preferably, the substrate of the inserter may comprise a material selected from silicon, glass, ceramics, or a combination of materials; silicon and glass are advantageous materials because their physical properties allow for a higher orbital density than that provided by other materials. In other words, silicon and glass allow for electrical insulation between two orbitals at a distance less than that required by another material (e.g., ceramics). Compared to glass, which offers the advantage of lower cost, silicon is the material that provides optimal heat dissipation.

[0048] Organic materials include, but are not limited to, epoxy resins, polyimides (such as polyimides sold under the name Kapton), and silicone resins.

[0049] Generally, the substrate forming the insert must have good heat resistance. Using inorganic materials, such as those previously mentioned, helps to transfer heat to the outside of the lighting element.

[0050] The inserter can have a general plate shape with two opposing faces. The electroluminescent source and electronic device can be arranged on different faces of the inserter, or on the same face. Arrangement means that there is a first contact between one face of the inserter and the electroluminescent source, and a second contact between one face of the inserter and the electronic device. The contacts are preferably permanent. Permanent contacts are made, for example, by soldering, bonding, or any given process such as "flip chip," "reflow soldering," "copper pillar," "microtube," "thermo-ultrasonic AuSn," "hybrid bonding," etc.

[0051] The lighting element may also include at least one heat sink disposed on at least one surface of the insert. The heat sink allows heat transfer from the electroluminescent source, such that heat from the electroluminescent source is transferred to the insert during use of the lighting element. Therefore, the fit between the heat sink and the insert, and the electroluminescent source, allows for the production of ground vehicle lighting modules that are easy to manufacture and install in vehicle lighting systems, resulting in a relatively small, compact size and good heat dissipation performance.

[0052] The heat sink allows for heat dissipation through cooperation with the substrate of the inserter; in other words, the heat sink receives heat generated by the electroluminescent source. Therefore, the heat sink is thermally connected to the inserter, which itself is thermally connected to the electroluminescent source.

[0053] Delivery can be provided by the fact that, in one example, the heat sink is positioned directly against the inserter. This means that the heat sink is in physical (i.e., material) contact with the inserter.

[0054] However, the heat sink can alternatively be arranged against the insert via an intermediate element that improves heat transfer. The intermediate element is arranged between the insert and the heat sink. The intermediate element may include, for example, a thermal compound or a phase change material. The intermediate element may include copper; for example, the intermediate element is a copper plate. The intermediate element may also be an adhesive that holds the heat sink against the insert.

[0055] Figure 2 An example is shown in which the electroluminescent source 200 and the electronic device 220 are arranged on the same side of the inserter 210. This configuration is particularly advantageous because it allows a heat sink (not shown) to be arranged on opposite sides of the inserter.

[0056] Similarly, in Figure 2 In the example, the electronic device includes control electronics, and it should be understood that the electronic device may include several control electronics. The electronic device can be configured to interact with the electroluminescent elements of the lighting element, for example, to individually control the emission or non-emission of light from each element. It should be understood that... Figure 2 The arrangement allows the electronics used to control the lighting elements to be placed as close as possible to the heat sink. Since these electronic components also generate heat, this arrangement optimizes heat dissipation. Furthermore, this arrangement allows for improved compactness of the lighting elements by primarily avoiding separation of control electronics from the lighting elements, thus providing additional space and necessary connectors. In fact, in situations such as... Figure 1 In the prior art shown, the driver, fixed to a component of the LED module, causes the LED to self-heat due to the driver, which reduces light intensity performance. Similarly, the driver is then heated by the LED, thus becoming more thermally sensitive. In the prior art, this may lead to an increase in heat sink size for a given cooling level.

[0057] The lighting element according to the invention may further include one or more passive electronic components, in other words, electronic components that do not amplify electrical signals. Alternatively, the lighting element according to the invention may further include one or more active electronic components, in other words, electronic components that amplify electrical signals. It should be understood that the lighting element may include both passive and active electronic components. These electronic components may, for example, be ESD protection capabilities, protective Zener diodes, or box resistors. These components may form part of an electronic circuit for controlling and protecting the electroluminescent source. It should also be understood that other elements of the lighting element may include passive and / or active electronic components; for example, the control element may be a component of an active electronic device and / or a passive electronic device.

[0058] The passive electronic components (or these) and / or active electronic components may be arranged at least partially on one surface of the inserter; such arrangement is achieved, for example, as previously discussed with regard to light sources and electronic devices.

[0059] The passive electronic components (or these) and / or active electronic components can be arranged within the inserter; in other words, they are implemented within the substrate of the inserter. In other words, the inserter serves not only as a support medium for conductive tracks but also as a support medium for electronic components. For example, the inserter can be envisioned as the substrate 204 of an electroluminescent element, which is an electroluminescent source. It is also envisioned that the inserter realizes electronic devices designed to control electroluminescent elements.

[0060] The lighting element may also include at least one electrical connector 240, which is disposed on an inserter and electrically connected to an electronic device. When the connector 240 is connected to a power source external to the lighting element, the connector allows the lighting element to be powered. In practice, the lighting element includes at least three connectors for supplying DC current to the lighting element; for example, a first connector supplies power to the module with a positive voltage, a second connector supplies power to the module with a negative voltage, and a third connector provides ground. Ground can be a low voltage (0 volts). The presence of the connectors facilitates the attachment or removal of the lighting element in devices using the lighting element based on the principles of SiP (System in Package). For example, the lighting element according to the invention can be easily attached by snap-fit ​​or screwed into an automotive headlight; it can also be easily removed from and replaced if defective.

[0061] A monolithic electroluminescent source has a high pixel density. The inserter for the lighting element according to the invention provides a substrate through which the light source can be electrically connected to an electronic device, because the inserter allows for a sufficient number of electrical tracks so that each element of the electroluminescent source can be controlled by the electronic device. However, to reduce the number of tracks that need to be wired on the inserter, several electroluminescent elements of the electroluminescent source can be electrically connected in series. The series-connected elements then require only a single common power supply; in other words, only a single track of the inserter is needed to electrically connect the electronic device and the series-connected electroluminescent elements. It should be understood that when the pixel density of the source is too high, the number of tracks that need to be “wired” on the inserter can be reduced.

[0062] The selection of electroluminescent elements connected in series can be arbitrary; for example, the elements of the source can be connected in pairs in series. This selection can also depend on the conditions of use of the lighting element. For example, if the lighting element is used as an illumination source and / or signal generation source for ground vehicles, then only certain areas of the electroluminescent source require full resolution (in other words, all electroluminescent elements must be individually controlled), while other areas require lower resolution (in other words, the electroluminescent elements do not need to be individually controlled).

[0063] Figure 3 An example is shown where the monolithic LED array 200 has been subdivided into nine regions. Regions labeled B, D, F, H, and I are those where maximum resolution has been preserved: each LED is individually controlled by electronics 220. Regions labeled A, C, E, and G are those where LEDs have been serialized to create groups. For example, region A is subdivided into six groups A1, A2, A3, A4, A5, and A6, and within each of these groups, the LEDs are connected in series, so that only a single track is needed to control them. Regions A, C, E, and G are located at the corners of the array because when using lighting elements as a light source for ground vehicles, the space illuminated by these regions does not require high resolution, as this space is at the periphery of the scene being illuminated.

Claims

1. A lighting module (20) for a ground vehicle, the lighting module comprising: - An electroluminescent source (200), the electroluminescent source comprising at least one electroluminescent element (202). - Electronic device (220), the electronic device being used to control the electroluminescent element; - Insertor (210), the inserter being electrically connected (230, 232, 234) to the electroluminescent source and the electronic device, in, - The electroluminescent source and the electronic device are arranged on the first surface of the inserter, and the heat sink is arranged against the second surface of the inserter; - The electroluminescent source is a monolithic matrix comprising multiple electroluminescent elements; - The inserter includes at least one metal track electrically connecting the electronic device and the at least one electroluminescent element of the electroluminescent source. The electroluminescent source is characterized by being further subdivided into: • At least one region of maximum resolution (B, D, F, H, I), in which each electroluminescent element is electrically connected to the electronic device via a metal track in the inserter, and • At least one lower resolution region (A, C, E, G), in which at least two electroluminescent elements are electrically connected in series to form a group of electroluminescent elements (A1, A2, A3, A4, A5), and the inserter includes a metal track electrically connecting the electronic device and the group of electroluminescent elements (A1, A2, A3, A4, A5).

2. The lighting module according to claim 1, wherein, The heat sink is arranged against the insert via an intermediate element, the intermediate element comprising at least one of the following: - Thermal paste; - Copper layer; - Adhesive.

3. The lighting module according to claim 1 or 2, wherein, The inserter comprises at least one of the following materials: - Inorganic materials; - Organic materials.

4. The lighting module according to claim 3, wherein, The inorganic material includes at least one of the following materials: - Silicon; - Glass; - ceramics.

5. The lighting module according to claim 1 or 2, wherein, The electronic device includes at least one power converter and / or integrated circuit.

6. The lighting module according to claim 1 or 2 further includes passive electronic components and / or active electronic components.

7. The lighting module according to claim 6, wherein, The electronic components are arranged on and / or in the inserter.

8. The lighting module according to claim 1 or 2, comprising at least one electrical connector (240) disposed on the inserter and electrically connected to the electronic device.

9. The lighting module according to claim 1 or 2, wherein, The at least one lower resolution region is located at the corner of the monolithic array of the electroluminescent element.

10. A lighting device comprising a lighting module according to any one of claims 1-9.

11. The lighting device according to claim 10, wherein, The lighting device is a lighting and / or signal indication device for ground vehicles.

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