Lighting devices with integrated screens for motor vehicles

Abstract

A lighting device (1) for a motor vehicle, comprising a plurality of first light sources (41) and a plurality of second light sources (42, 43, 44) capable of selective activation, the plurality of first light sources and the plurality of second light sources being arranged on a common substrate (4), and each of the plurality of first light sources being positioned at a distance of less than 1 mm from the other light sources of the plurality of first light sources, characterized in that the lighting device comprises an optical element (5) having a first area (51) and a second area (52, 53, 54), the first area being positioned facing the plurality of first light sources, the second area being positioned facing the plurality of second light sources, the second area being provided with an optical pattern (62, 63, 64).

Description

Technical Field

[0001] This invention relates to the field of motor vehicle lighting. More precisely, this invention relates to the field of screen-based motor vehicle signaling. Background Technology

[0002] It is known to embed screens in the lighting devices of motor vehicles, and more specifically in the light-emitting and signaling devices of motor vehicles, to display information for use by road users, such as displaying pictograms indicating that a door is opening or that there is a vehicle slowing down ahead.

[0003] To create such a screen, it is also known to use small, unencapsulated light sources, and in particular, unencapsulated housings for these light sources (e.g., micro-LEDs). These two features make it possible to create a compact screen with high resolution and sufficient brightness to ensure that the information displayed on the screen is visible to road users both day and night.

[0004] However, a standalone screen cannot perform all the prescribed light intensity functions that must be performed by a signaling device. Specifically, regulations control signaling functions that must be performed by a front or rear signaling device (e.g., brake lights, position lights, or even turn indicators). Although regulations vary between countries, they all define minimum light intensities that signaling functions must achieve, among many other requirements. For example, European regulations specify a minimum light intensity of approximately 25cm. 2 The visible area of ​​these functions requires a minimum value of 30,000 Cd / m² for brake lights. 2 The minimum value for the direction indicator is 70000 Cd / m. 2 However, the type of screen described above can only achieve a maximum of 5000 Cd / m². 2 The intensity. Therefore, it is necessary to include other light sources in the signaling device, which enable the execution of these various prescribed signaling functions.

[0005] Furthermore, it is known that light sources forming a screen are mounted on a substrate that allows for the selective activation of each light source. However, this type of substrate has a generally rectangular standard shape, which imposes a specific shape on the screen. There is a need to create screens with signal transmitting devices that have free shapes and are not necessarily rectangular.

[0006] Finally, in lighting installations, the juxtaposition of screens with other lighting or signaling functions becomes complicated due to the need to observe the space between the screen and adjacent functions. This space can therefore create a disruption in the overall aesthetic appearance of the lighting installation and increase its size. Summary of the Invention

[0007] The present invention falls within this context, and is intended to satisfy the aforementioned various needs by providing a lighting device for motor vehicles, which incorporates a screen whose shape is not constrained by the technology constituting the screen, and which enables at least one prescribed light intensity function to be performed in addition to the screen without creating an interruption in aesthetic appearance or increasing the size of the lighting device.

[0008] Therefore, the subject of this invention is a lighting device for a motor vehicle, the lighting device comprising a plurality of first light sources and a plurality of second light sources that can be selectively activated, the plurality of first light sources and the plurality of second light sources being arranged on a common substrate, and each of the plurality of first light sources being positioned at a distance of less than 1 mm from the other light sources of the plurality of first light sources, characterized in that the lighting device includes an optical element having a first region and a second region, the first region being positioned facing the plurality of first light sources, the second region being positioned facing the plurality of second light sources, and the second region having an optical pattern.

[0009] It should be understood that, with the aid of this invention, on the one hand, there are multiple first light sources positioned sufficiently close to each other to create a screen through a first region of optical elements. On the other hand, there are multiple second light sources whose light distribution can be rationally dispersed by means of an optical pattern in a second region to perform a prescribed photometric function, particularly in terms of minimum light intensity. Furthermore, the common substrate can maintain its standard shape, and the shape of the screen itself is defined by the positioning of the multiple first light sources on the substrate and the shape of the first region (both of which can be flexible). Finally, positioning the light sources on the same substrate avoids disruption to the aesthetic appearance of the lighting device between the screen and the prescribed photometric function, and avoids increasing the size of the device.

[0010] Advantageously, the optical element is a single component. If necessary, the distance from the optical element to each of the plurality of first light sources and the plurality of second light sources can be less than 1 millimeter.

[0011] In one exemplary embodiment, the first region is the central region of the optical element, and the second region is a peripheral region of the optical element extending over all or part of the periphery of the central region. If desired, the second region may include multiple sub-regions, each positioned to face a separate set of light sources among a plurality of second light sources. Where appropriate, the light sources among the plurality of first light sources are arranged in an arrangement corresponding to the shape of the first region.

[0012] "Optical pattern" specifically refers to one or more of the following elements: for example, cylindrical outlines (godrons); collimators, such as lens collimators and / or total internal reflection collimators; prisms. If desired, the optical pattern can be positioned on the incident surface of the optical element, oriented toward the light source and / or the exit surface of the optical element, oriented toward the exterior of the device. For example, the outline of each optical pattern can be defined according to the curvature and / or tilt of the optical element.

[0013] Advantageously, each of the plurality of first light sources has a size of less than 500 micrometers, and the light sources are spaced apart from each other at a distance of less than 1 millimeter. "Size of light source" refers to the width and / or length of the light-emitting surface of the light source. Preferably, all light sources of the plurality of first light sources have the same size. By way of example, each of the plurality of first light sources can be a semiconductor light-emitting unit with a size between 100 and 300 micrometers. As a variation, each of the plurality of first light sources can be a semiconductor light-emitting unit with a size of less than 100 micrometers, particularly including those with a size between 30 and 60 micrometers. Where appropriate, the light sources of the plurality of first light sources can be uniformly arranged on a common substrate, for example, with a spacing of less than or equal to 800 micrometers, or even less than or equal to 300 micrometers. Preferably, each of the plurality of first light sources is not encapsulated at all, for example, with a connector or optical element incorporated therein, and is directly mounted on and connected to the common substrate.

[0014] In one embodiment of the invention, the light sources among the plurality of second light sources have the same characteristics as the light sources among the plurality of first light sources. "Characteristics" specifically refers to the size and internal structure of the light source, the arrangement spacing, and the fact that each of the plurality of second light sources can be selectively activated. As a variation, it can be specified that the light sources among the plurality of second light sources differ from the light sources among the plurality of first light sources in at least one characteristic, and particularly in one of the characteristics mentioned above. For example, it can be specified that the light sources among the plurality of second light sources are divided into various different groups that can be selectively activated, or even that these light sources are activated only simultaneously.

[0015] Advantageously, the ratio between the distance separating two of the plurality of second light sources and the size of each of the plurality of second light sources is greater than or equal to 2. This ratio is called the distance ratio. Preferably, the distance ratio can be greater than or equal to 5. As a variation, the area fill ratio, also called the fill factor, which is the square of the distance separating two of the plurality of second light sources divided by the area of ​​each of the plurality of second light sources, can be greater than or equal to 25.

[0016] Advantageously, the common substrate is an active matrix substrate arranged to selectively control each of the plurality of first light sources, each of the plurality of first light sources being mounted and connected to the common substrate by means of a thin-film transistor integrated into the common substrate. Where appropriate, the active matrix substrate is also arranged to selectively control each of the plurality of second light sources. If desired, the common substrate may be curved or flexible.

[0017] Advantageously, each optical pattern in the second region is arranged to receive light emitted by one of the plurality of second light sources and to focus these light rays along a given emission axis. For example, each optical pattern may have a profile whose shape is configured to modify the distribution of light emitted by the light source, particularly the Lambertian distribution of these light rays, in order to obtain a brightness greater than that of the light source. This feature is particularly advantageous when the distance ratio is greater than or equal to two, or when the fill factor is greater than or equal to four, in which case the apparent brightness output from the optical pattern, that is, the apparent brightness for an observer located at a distance from the illumination device, is proportional to the brightness of the light source multiplied by the square of the fill factor. If desired, each optical pattern may have a profile whose shape is configured to disperse the light emitted by the light source in a horizontal direction, particularly when the light source has a substantially square luminous surface.

[0018] Advantageously, the first region is scattering. For example, the first region includes a texture, particularly on the surface oriented outwards toward the lighting device. This feature allows the visible appearance of one of a plurality of first light sources to be obscured by the first region of the optical element, especially when the spacing between the light sources is too large. As a variation, the first region can be smooth, for example when the spacing is less than 800 micrometers, or even less than 500 micrometers.

[0019] If desired, the first region can be coated with an anti-reflective coating. Potentially, the second region can also be coated with an anti-reflective coating. This feature allows for a reduction in the impact of light sources on the visible appearance of pixels formed by adjacent light sources.

[0020] Advantageously, each of the plurality of first light sources has a size of less than 500 micrometers, and the light sources of the plurality of first light sources are separated from each other by a distance of less than 1 millimeter, and the distance ratio of the plurality of second light sources is greater than 2, and / or the area fill ratio of the plurality of second light sources is greater than or equal to four, and each optical pattern of the second region is arranged to receive light emitted by one of the plurality of second light sources and to focus the light along a given emission axis, while the first region is either scattering or smooth.

[0021] Advantageously, the lighting device includes a control unit arranged to selectively control one of the plurality of first light sources, such that the lighting device forms a screen in the first region of the optical element. The control unit is also arranged to control one of the plurality of second light sources, such that the lighting device emits at least one light beam as output from the second region of the optical element, the at least one light beam participating in the execution of a predetermined signaling function. In other words, the light emitted by one of the plurality of first light sources can form pixels of the screen. Furthermore, the light emitted by the light sources of the plurality of second light sources and deflected by an optical pattern together form at least one light beam, which performs all or part of the predetermined signaling function. Preferably, the control unit is arranged to receive instructions from a computer of the motor vehicle and, according to the instructions, control the light sources of the device, for example, to display pictograms on the screen and / or create position lights, brake lights, and / or direction indicators. In the case where the second region comprises multiple sub-regions, each sub-region is oriented toward a separate group of light sources among multiple second light sources, and the control unit can be arranged to selectively control each group of said groups, such that each group emits a beam of light deflected by the optical pattern of the associated sub-region to perform a separate predetermined signaling function. Attached Figure Description

[0022] The invention will now be described by way of example and with reference to the accompanying description. These examples are merely illustrative and are in no way intended to limit the scope of the invention. In the accompanying drawings:

[0023] [ Figure 1 The image shows a front view of a lighting device according to an embodiment of the present invention;

[0024] [ Figure 2 The diagram shows the composition of [ Figure 1 The various components of the lighting device;

[0025] [ Figure 3 ] shows along [ Figure 1 A cross-sectional view of the first plane of the lighting device;

[0026] [ Figure 4 ] shows along [ Figure 1 A cross-sectional view of the second plane of the lighting device. Detailed Implementation

[0027] exist[ Figure 1 The image shows a lighting device 1 for a motor vehicle, including a taillight 2.

[0028] The taillight 2 is divided into multiple segments, each segment performing one or more given functions. In the described example, the taillight 2 is divided into: a central segment for creating the screen 21, a lower left peripheral segment for creating the direction indicator 22, a lower right peripheral segment for creating the rear fog light 23, and an upper peripheral segment that alternately participates in the creation of the position light and the brake light 24.

[0029] The lighting device 1 also includes a control unit 3, which is arranged to receive instructions I sent by the central computer of the motor vehicle, and to control the activation and / or deactivation of the various mentioned functions and the display of the pictogram P on the screen 21 according to the instructions I.

[0030] Now we will combine [ Figure 2 The structure of taillight 2 is described using the following.

[0031] The taillight 2 includes on one side a plurality of first light sources 41 for creating a screen 21 and a plurality of second light sources divided into groups 42, 43 and 44, each group being used to perform the functions of the direction indicator 22, the rear fog light 23 and the position light / brake light 24, respectively.

[0032] Multiple first light sources and multiple second light sources are arranged on a common substrate 4.

[0033] In the described example, all of the plurality of first light sources 41 are microLEDs, i.e., unpackaged semiconductor light-emitting units with dimensions (i.e., length and width) of 60 micrometers. These units are arranged in a matrix on a common substrate 4 and are uniformly spaced at a pitch of 300 micrometers. It should be noted that the distance ratio of the plurality of first light sources 41 (i.e., the ratio between the spacing of these light sources and the size of these light sources) can be between 3 and 8.

[0034] Multiple second light sources 42, 43, and 44 are also micro-LEDs, whose size and arrangement on the common substrate 4 are consistent with the multiple first light sources 41. It should be noted that these light sources can vary depending on the segment of the taillight they are used to create, particularly in terms of the color of the light emitted, size, and spacing. Specifically, the signaling functions mentioned above are subject to color-specific requirements. For example, the function of the turn indicator must be performed by an amber beam, while the functions of the position lights and brake lights must be performed by a red beam. Therefore, the use of the following micro-LEDs is conceivable:

[0035] a. The color of the light directly emitted by the microLED corresponds to the color required for the segment created by the microLED;

[0036] b. The microLEDs are small in size and are arranged with a smaller spacing relative to the screen. These microLEDs emit light of different colors, such that adjacent microLEDs emit their colors together and synthesize them additively to produce light corresponding to the color required for the segment that the microLED is used to create.

[0037] c. The color of the light emitted by the micro-LED is then modified by a filter.

[0038] refer to[ Figure 2 It should be noted that the arrangement of the multiple first (light sources) 41 and the arrangement of the multiple second (light sources) in different groups 42, 43 and 44 correspond to the shapes of the different segments 21, 22, 23 and 24. All the light sources still form a single component arranged on the common substrate 4, and there are no light sources at the corners 45 of the common substrate.

[0039] The common substrate 4 is a rectangular and flexible active matrix substrate. Each of the plurality of first light sources and the plurality of second light sources is mounted and connected to the common substrate 4 by means of thin-film transistors (TFTs) integrated into the common substrate. This type of substrate allows each of the light sources to be selectively controlled by means of a control unit 3. It is understood that, in the described example, the light sources in the same group 42, 43, or 44 are controlled together to control the activation and / or deactivation of the function performed by that group of light sources, while the plurality of first light sources 41 can be selectively controlled so that each light source forms a pixel of screen 21, thereby enabling the display of a pictograph P on screen 21. As a variation, it is possible to specify selective control of each of the light sources in groups 42, 43, 44, for example, to perform a dynamic lighting function.

[0040] Since the substrate 4 is flexible, the corner 45 can be folded toward the rear of the taillight 2, so that the corner is not visible to users outside the vehicle.

[0041] The taillight 2 also includes an optical element 5, which is a single piece, a transparent or translucent component, positioned at a distance of 500 micrometers facing the common substrate 4 in order to receive light emitted by the light source.

[0042] More specifically, the optical element 5 is divided into a first central region 51 and a second peripheral region that itself includes sub-regions 52, 53 and 54.

[0043] The first central region 51 is positioned to face a plurality of first light sources 41, and the shape of the first central region 51 substantially corresponds to the shape of the arrangement of these light sources and the shape of the arrangement of the segments 21. Similarly, each of the sub-regions 52, 53 and 54 is positioned to face one of the groups 42, 43 and 44 of a plurality of second light sources, respectively.

[0044] [ Figure 3 ]and[ Figure 4 The image shows the taillight 2 along [...]. Figure 1 The cross-sections of vertical planes P1 and P2 shown in the figure enable an understanding of the structure and function of these first and second regions.

[0045] The first central region 51 has a texture 61 on its emitting surface (i.e., the surface facing outward toward the taillight 2). This texture allows light emitted by the plurality of first light sources 41 to be diffused, for example, to prevent the spacing between these light sources from being seen by a user located outside the vehicle. Furthermore, the first central region 51 has an anti-reflective coating that prevents light emitted by one of the plurality of first light sources 41 from damaging the appearance of pixels formed by adjacent light sources.

[0046] Each sub-region 52, 53 and 54 of the optical element 5 includes optical patterns 62, 63 and 64 formed on the exit surface of the sub-region.

[0047] Each optical pattern 62, 63, or 64 of sub-regions 52, 53, or 54 is arranged to receive light rays F emitted by one of the light sources of the group 42, 43, or 44 associated with the sub-region, and to focus these light rays F such that the apparent brightness output from the optical pattern is greater than the brightness of the light source.

[0048] In the described example, each optical pattern 62, 63, and 64 so associated with one of the light sources in groups 42, 43, or 44 is a tortuous surface decoration (godron), that is, having one curvature in one direction and another curvature in another direction, which is determined in particular by the distance of the associated light source to the optical element 5, the curvature of the optical element 5 perpendicular to the light source, and the function of signaling functions 22, 23, and 24 performed by the group to which the light source belongs.

[0049] This ensures that each beam of light created by the light source F of each of groups 42, 43 and 44 and deflected by the optical elements 62, 63 and 64 of sub-regions 52, 53 and 54 meets the requirements specified in management functions 22, 23 and 24, particularly the requirements regarding minimum light intensity.

[0050] It should be noted that the taillight 2 may include elements different from those shown in the figure, and in particular includes a housing and an enclosed outer lens that define the space in which the common substrate 4 and the optical element 5 are arranged.

[0051] The above description clearly explains how the present invention can achieve its intended objective, namely, to provide an illumination device for a vehicle incorporating a free-form screen, and the illumination device is also capable of performing one or more prescribed photometric functions, which is achieved by positioning the light source required to perform these functions and the light source required to create the screen on the same substrate, and by extending the optical elements of the screen so that optical patterns can be added to the optical elements so that the emitted light can be deflected, thereby complying with the requirements for managing these photometric functions.

[0052] In no event should the invention be considered limited to the embodiments specifically described herein, and in particular extends to any equivalent means and any technically operable combination of such means. Optical patterns having contours or types different from those described are particularly conceivable, and in particular collimators, microlenses, or even prisms.

Claims

1. A lighting device (1) for a motor vehicle, the lighting device (1) comprising a plurality of first light sources (41) and a plurality of second light sources (42, 43, 44) capable of selective activation, the plurality of first light sources and the plurality of second light sources being arranged on a common substrate (4), and each of the plurality of first light sources being positioned at a distance of less than 1 mm from the other light sources of the plurality of first light sources, characterized in that, The lighting device includes an optical element (5) having a first region (51) and a second region (52, 53, 54), the first region (51) being configured to perform a first function and positioned facing the plurality of first light sources, the second region (52, 53, 54) being configured to perform a second function and positioned facing the plurality of second light sources, the second region having an optical pattern (62, 63, 64), wherein the first function and the second function are different.

2. The apparatus (1) according to claim 1, characterized in that, Each of the plurality of first light sources (41) has a size of less than 500 micrometers, and the light sources of the plurality of first light sources are separated from each other by a distance of less than 1 millimeter.

3. The apparatus (1) according to claim 1 or 2, characterized in that, The light sources in the plurality of second light sources (42, 43, 44) have the same characteristics as the light sources in the plurality of first light sources (41).

4. The apparatus (1) according to claim 3, characterized in that, The ratio between the distance separating two of the plurality of second light sources (42, 43, 44) and the size of each of the plurality of second light sources is greater than 2.

5. The apparatus (1) according to claim 1 or 2, characterized in that, The common substrate (4) is an active matrix substrate, which is arranged to selectively control each of the plurality of first light sources (41), each of the plurality of first light sources being mounted on and connected to the common substrate by means of a thin-film transistor integrated into the common substrate.

6. The apparatus (1) according to claim 1 or 2, characterized in that, Each optical pattern (62, 63, 64) in the second region (52, 53, 54) is arranged to receive light rays (F) emitted by one of the plurality of second light sources (42, 43, 44) and to focus these light rays along a given emission axis.

7. The apparatus (1) according to claim 1 or 2, characterized in that, The first region (51) is scattering.

8. The apparatus (1) according to claim 1 or 2, characterized in that, The first region (51) is coated with an anti-reflective coating.

9. The lighting device (1) according to claim 1 or 2, characterized in that, The lighting device includes a control unit (3) arranged to selectively control one of the plurality of first light sources (41) such that the lighting device forms a screen (21) in the first region (51) of the optical element (5), and the control unit is arranged to control one of the plurality of second light sources (42, 43, 44) such that the lighting device emits at least one light beam as an output from the second region (52, 53, 55) of the optical element, the at least one light beam participating in the execution of a predetermined signaling function (22, 23, 24).

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