Combined system forming a screen

Abstract

Combined system forming a screen. The invention relates to a combined system (1) forming a screen, comprising: a TFT-LCD type assembly (2), having an upper glass supporting a color filter and a lower glass supporting a thin-film transistor (TFT) structure, the lower glass being configured to be placed on the side of a backlight structure, this TFT-LCD assembly having an active display area (3) and a passive area (4), a camera (10) placed on the side of the lower glass of the TFT-LCD assembly, opposite the passive area (4), this camera being configured to capture useful radiation, for example visible light, and the active display area of ​​the TFT-LCD assembly being substantially obstructing the useful radiation of the camera and the passive area being configured to allow the useful radiation of the camera to pass through, a microLED structure (20) placed on an external face of the upper glass of the TFT-LCD assembly,at the right of the passive zone, so that the camera can capture the useful radiation that has passed through the passive zone and the microLED structure (20). Figure for the abbreviation: Figure 1,

Description

Title of the invention: Combined system forming a screen

[0001] The present invention relates in particular to a combined system forming a screen, in particular intended to be installed on board a vehicle.

[0002] The vehicle can be land, sea or air.

[0003] Currently, vehicles are equipped with DMS (Driver Monitoring System) cameras which are used, for example, to monitor the driver's fatigue level. These cameras generally use image processing algorithms to detect various facial characteristics and movements, such as gaze, head position and eye blinking.

[0004] These cameras are integrated into the passenger compartment in various positions, for example in a windshield pillar (generally on the driver's side), above or below the instrument cluster or in the central rearview mirror.

[0005] However, the integration of the camera appears as an additional part which is very visible to the user, and quite unsightly.

[0006] Patent application US20210356788 describes an LCD device that includes a liquid crystal module, a backlight module, an under-screen sensor, and a low-brightness micro-light-emitting diode (LED) module.

[0007] The invention aims in particular to improve the integration of cameras, in particular in the passenger compartment of a vehicle.

[0008] The invention thus relates to a combined system forming a screen, comprising: - a TFT-LCD type assembly, comprising an upper glass supporting a color filter and a lower glass supporting a thin film transistor (TFT) structure, the lower glass being configured to be placed on the side of a backlight structure, this TFT-LCD assembly having an active display area and a passive area, - a camera placed on the lower glass side of the TFT-LCD assembly, opposite the passive zone, this camera being configured to capture useful radiation, for example visible light, and the active display zone of the TFT-LCD assembly being substantially obstructive for the useful radiation of the camera and the passive zone being configured to let the useful radiation of the camera pass, - a microLED structure placed on an external face of the upper glass of the TFT-LCD assembly, at the right of the passive zone, so that the camera can capture the useful radiation having passed through the passive zone and the microLED structure.

[0009] The invention is advantageous because it allows the TFT-LCD technology to be retained. which is a less expensive technology, for example compared to OLED technology. The invention makes it possible in particular to retain the TFT-LCD type assembly while providing a passive zone which allows the camera to operate correctly while allowing, when the camera is inactive, to have a display thanks to the microLED structure. This display can, if desirable, be continuous with the display produced by the TFT-LCD type assembly. The invention is more advantageous than the solution described in patent application US20210356788 which recommends placing the microLEDs between the lower and upper glasses of the LCD structure. In the present invention, it is simpler to produce the combined system because it is sufficient to place the microLED structure on the upper glass, and it is not necessary to completely redesign the TFT-LCD assembly to separate the glasses to insert the microLEDs.

[0010] Since microLED technology is generally more expensive than TFT-LCD technology, the invention makes it possible to limit the extent of the microLED structure to just what is necessary to allow normal camera operation, namely to allow this camera to receive the useful radiation which is not altered by passing through the TFT-LCD type assembly.

[0011] The passive zone according to the invention is sufficiently transparent for the useful radiation of the camera, for example sufficiently transparent for the light captured by the camera.

[0012] Generally speaking, the invention makes it possible to hide the camera, at a limited cost and in an efficient manner.

[0013] According to one aspect of the invention, the passive zone of the TFT-LCD type assembly is devoid of a color filter.

[0014] According to one aspect of the invention, the TFT-LCD type assembly may comprise a colored filter extending into the active display area and outside the passive area.

[0015] According to one aspect of the invention, the passive area is devoid of transistors used in the TFT-LCD function, while the active display area comprises transistors of the TFT LCD function.

[0016] According to one aspect of the invention, the TFT-LCD assembly comprises a liquid crystal layer. This liquid crystal layer extends into the active display area without overflowing into the passive area of ​​the TFT-LCD assembly.

[0017] According to one aspect of the invention, in the passive zone, the TFT-LCD assembly mainly comprises one or more glasses which do not alter the useful radiation which the camera must capture.

[0018] This ensures proper operation of the camera.

[0019] According to another aspect of the invention, the liquid crystal layer also extends in the passive zone and the TFT-LCD assembly has, in the passive zone, a polarization of the liquid crystal layer to allow the passage of useful radiation towards the camera.

[0020] According to one aspect of the invention, the microLED structure comprises a microLED array. This array comprises pixels each formed by three microLEDs of different colors.

[0021] According to one aspect of the invention, the microLED array of the microLED structure has the same pitch as that of the TFT-LCD assembly.

[0022] This allows for a homogeneous display on both the active display area of ​​the TFT-LCD assembly and the microLED structure.

[0023] Alternatively, the pitch in the microLED array of the microLED structure may be different from the pitch of the TFT-LCD assembly, in particular with a ratio of an integer multiple.

[0024] According to one aspect of the invention, the microLED structure is semi-transparent for the useful radiation of the camera. Thus the microLED structure allows only a part of the useful radiation to pass through, the other part of this useful radiation being able to be absorbed or reflected by the microLED structure, with however the transmitted part being sufficient to allow the sensor to operate efficiently.

[0025] According to one aspect of the invention, the microLED structure comprises an array of microLEDs which are arranged on one face of the microLED structure leaving free gaps between the microLEDs.

[0026] This makes the microLED structure semi-transparent to useful radiation.

[0027] According to one aspect of the invention, the microLED structure may comprise addressing lines configured to drive the microLED array.

[0028] According to one aspect of the invention, the addressing lines are on the upper glass and are connected to a flexible connection.

[0029] In an exemplary implementation of the invention, the passive area is completely surrounded by the active display area of ​​the TFT-LCD assembly.

[0030] According to one aspect of the invention, the camera comprises a lens.

[0031] According to one aspect of the invention, the camera lens is optically bonded on the lower glass of the TFT-LCD assembly.

[0032] This makes it possible to optimize the optical efficiency.

[0033] According to one aspect of the invention, addressing lines are positioned on the upper glass of the TFT-LCD assembly in order to drive the microLED array of the microLED structure.

[0034] According to one aspect of the invention, the microLED structure is configured to be driven independently of the TFT-LCD assembly for the displays.

[0035] In this case, the microLED structure can be driven using a video stream specific or by extracting part of the video stream intended for TFT-LCD assembly.

[0036] Alternatively, the microLED structure is configured to be driven by electronics for driving the TFT-LCD assembly.

[0037] In an exemplary embodiment of the invention, the combined system is configured to synchronize the acquisition of the camera with the display of the microLED structure, in particular so as to avoid an acquisition of the camera at the same time as the display by the microLED structure.

[0038] This makes it possible to limit the quantity of stray light produced by the microLED structure during acquisition by the camera.

[0039] According to one aspect of the invention, the microLED structure comprises microLEDs which have a characteristic dimension (for example a diameter or a side of the microLED) of less than 200 pm, being for example between 20 and 400 pm, in particular between 20 and 150 pm. In the present invention, the term microLED is used to also encompass a miniLED.

[0040] According to one aspect of the invention, the surface area of ​​the microLED structure is greater than the dimension of the camera lens.

[0041] According to one aspect of the invention, the surface area of ​​the camera lens is chosen to be less than 8 cm2, preferably less than 4 cm2.

[0042] For example, the microLED structure is configured to produce a display with an extent of 20 mm by 20 mm.

[0043] According to one aspect of the invention, the microLED array on the microLED structure has a pitch of 130 pm making it possible to obtain a resolution of the order of 195 ppi (in English "pixels per inch" or in French "pixels per inch") or 77 pixels per cm.

[0044] According to one aspect of the invention, the number of microLEDs in the microLED structure may be 160 x 160 x 3 or 76,800, the multiplication by 3 corresponding to the three colors to produce the display.

[0045] This makes it possible to limit the overall cost.

[0046] In an exemplary embodiment of the invention, the microLED structure comprises a substrate, for example in the form of a pellet, and the microLEDs are arranged on one face of this substrate, which is in particular made of transparent glass.

[0047] According to one aspect of the invention, the microLED structure, in particular the substrate, has a polygonal periphery, for example rectangular or square.

[0048] Alternatively, the rim may be round or oval.

[0049] According to one aspect of the invention, the microLED structure is placed on the TFT-LCD assembly with the microLED array facing this external face of the upper glass of the TFT-LCD assembly.

[0050] The substrate of the microLED structure is then oriented opposite the TFT-LCD assembly.

[0051] According to one aspect of the invention, the TFT-LCD assembly comprises on its external face a polarizer, in particular in the form of a layer (or film) on this external face.

[0052] According to one aspect of the invention, the polarizer is glued to the upper glass of the TFT-LCD assembly by an optical glue or OCA (in English “Optical Clear Adhesive”).

[0053] According to one aspect of the invention, the polarizer, in particular in the form of a film deposited on the upper glass, comprises an opening in which the microLED structure extends.

[0054] According to one aspect of the invention, the microLEDs are embedded in the optical glue layer.

[0055] According to one aspect of the invention, the thickness of the optical glue layer is sufficient to embed the microLEDs in its thickness.

[0056] In an exemplary embodiment of the invention, the thickness of the optical glue is between 20 and 250 μm.

[0057] According to one aspect of the invention, this thickness of the glue is adjusted according to the dimensions of the microLEDs.

[0058] According to one aspect of the invention, the TFT-LCD assembly comprises an upper glass with a thickness of between 50 μm and 300 μm, in particular between 100 μm and 300 μm.

[0059] This ensures the continuity of the display surfaces of the TFT-LCD assembly and the microLED structure, which improves the perceived quality for the overall display.

[0060] In another exemplary embodiment of the invention, instead of a substrate (for example in the form of a pellet) which supports the microLEDs, the microLEDs are deposited directly on the upper glass, in particular on an area without a polarizer. The microLEDs deposited on the upper glass are in particular embedded in a layer of optical glue (OCA type) present on the upper glass.

[0061] According to one aspect of the invention, the combined system comprises a backlighting structure placed opposite the lower glass of the TFT-LCD assembly.

[0062] According to one aspect of the invention, the microLEDs occupy, for example, approximately 25% of the total surface area of ​​the microLED structure.

[0063] According to one aspect of the invention, the microLED structure has a slight overhang on the surface of the TFT-LCD assembly so that the microLED structure is sensitive to touch by a person.

[0064] Alternatively, the microLED structure may be configured to be undetectable to the touched by a person.

[0065] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawing in which:

[0066] - [Fig.l] illustrates, schematically and partially, in section, a combined system according to an example of implementation of the invention;

[0067] - [Fig.2] illustrates, schematically and partially, the combined system of the [Fig.l], in front view;

[0068] - [Fig.3] illustrates, schematically and partially, the control of the system combined from [Fig.l];

[0069] - [Fig.4] illustrates, schematically and partially, another example of control of the combined system of [Fig.l];

[0070] - [Fig.5] illustrates, schematically and partially, in section, a structure with microLED of the combined system of [Fig.l],

[0071] - [Fig.6] illustrates, schematically and partially, in section, a structure with microLED combined system according to another exemplary embodiment of the invention.

[0072] [Fig.l] shows a combined system 1 forming a screen, comprising: - an assembly 2 of the TFT-LCD type, comprising an upper glass 14 supporting a color filter 18 and a lower glass 17 supporting a thin-film transistor (TFT) structure 23, the lower glass 17 being configured to be placed on the side of a backlighting structure 9, this TFT-LCD assembly 2 having an active display area 3 and a passive area 4, - a camera 10 placed on the lower glass side of the TFT-LCD assembly, opposite the passive zone 4, this camera 10 being configured to capture useful radiation, for example visible light, and the active display zone 3 of the TFT-LCD assembly being substantially obstructive for the useful radiation of the camera 10 and the passive zone 4 being configured to let the useful radiation of the camera 10 pass through, - a microLED structure 20 placed on an external face 6 of the upper glass 14 of the TFT-LCD assembly, at the right of the passive zone 4, so that the camera 10 can capture the useful radiation having passed through the passive zone 4 and the microLED structure 20.

[0073] The passive zone 4 according to the invention is sufficiently transparent for the useful radiation of the camera 10, sufficiently transparent for the light captured by the camera 10.

[0074] The passive zone 4 of the TFT-LCD assembly 2 may be devoid of a colored filter (or color filter).

[0075] In particular, the colored filter 18, which is present between the upper glass 14 and the lower glass 17, extends to the right of the active display zone 3 and outside the passive zone 4.

[0076] The passive area 4 is devoid of transistors used in the TFT-LCD function, while the active display area 3 comprises transistors of the TFT LCD function. In other words, the thin-film transistor (TFT) structure 23, which is present between the upper glass 14 and the lower glass 17, extends in line with the active display area 3 and outside the passive area 4.

[0077] The TFT-LCD assembly 2 comprises a liquid crystal layer between the upper glass 14 and the lower glass 17. This liquid crystal layer (not shown) extends into the active display area 3 without overflowing into the passive area 4 of the TFT-LCD assembly 2.

[0078] In the passive zone 4, the TFT-LCD assembly 2 mainly comprises one or more glasses which do not alter the useful radiation which the camera 10 must capture.

[0079] The backlight structure 9 is provided at the rear of the TFT-LCD assembly 2.

[0080] This ensures proper operation of the camera 10.

[0081] Where appropriate, when the liquid crystal layer extends over the entire surface, the TFT-LCD assembly 2 has, in the passive zone 4, a polarization of the liquid crystal layer to allow the passage of useful radiation towards the camera 10.

[0082] The microLED structure 20 comprises a microLED array 21 (LEDs of microscopic dimensions in particular), as can be seen in [Fig. 2]. This microLED array 21 forms image pixels.

[0083] The microLED array 21 of the microLED structure 20 has the same pitch as that of the TFT-LCD assembly 2, resulting in a similar image resolution.

[0084] This makes it possible to have a homogeneous display on both the active display area 3 of the TFT-LCD assembly 2 and the microLED structure 20.

[0085] Alternatively, the pitch in the microLED array of the microLED structure 20 may be different from the pitch of the TFT-LCD assembly 2.

[0086] The microLED structure 20 is semi-transparent for the useful radiation of the camera 10. Thus the microLED structure 20 allows only a part of the useful radiation to pass through, the other part of this useful radiation being able to be absorbed or reflected by the microLED structure 20, with however the transmitted part being sufficient to allow the sensor 10 to operate efficiently.

[0087] The microLED structure 20 comprises an array of microLEDs 21 which are arranged on one face of the microLED structure 20 leaving free gaps 22 between the microLEDs 21.

[0088] This makes the microLED structure 20 semi-transparent to useful radiation.

[0089] The microLED structure 20 may comprise addressing lines 29 configured to drive the microLED array 21.

[0090] The addressing lines can be connected to a flexible connection 15.

[0091] In an exemplary implementation of the invention, the passive zone 4 is completely surrounded by the active display zone 3 of the TFT-LCD assembly 2.

[0092] The camera 10 comprises a lens 11 and an electronic card 19 on which the lens 11 rests.

[0093] The lens 11 of the camera 10 is optically bonded to the lower glass 17 of the TFT-LCD assembly 2 via a layer of optical glue 12.

[0094] This makes it possible to optimize the optical efficiency.

[0095] The microLED structure 20 is positioned on the upper glass 14.

[0096] In the example of [Fig. 3], the microLED structure 20 can be driven using an electronic drive component 25 of the TFT-LCD assembly 2. In other words, this electronic drive component 25 directly drives the TFT-LCD assembly 2 and the microLED structure 20. A synchronization 26 is provided between the electronic drive component 25 and the camera 10. Thus it is for example possible to turn off the microLED structure 20 when the camera 10 is activated.

[0097] In the example of [Fig. 4], the microLED structure 20 is configured to be driven independently of the TFT-LCD assembly 2 for the displays. In the example of [Fig. 4], a video stream extraction unit 27 is provided, placed upstream of the electronic drive component 25 of the TFT-LCD assembly 2, to extract the video stream and send it to the microLED structure 20.

[0098] In a variant not shown, a specific video stream can be provided for the microLED structure 20.

[0099] The combined system 1 is configured to synchronize the acquisition of the camera 10 with the display of the microLED structure 20, in particular so as to avoid an acquisition of the camera 10 at the same time as the display by the microLED structure 20.

[0100] This makes it possible to limit the quantity of stray light produced by the microLED structure 20 during acquisition by the camera 10.

[0101] The microLED structure 20 comprises microLEDs which have a characteristic dimension (for example a diameter or a side of the microLED) less than 200 pm, being for example between 20 and 150 pm.

[0102] The surface area of ​​the microLED structure 20 is greater than the dimension of the lens 11 of the camera 10.

[0103] The surface area of ​​the lens 11 of the camera 10 is chosen to be less than 4 cm2.

[0104] For example, the microLED structure 20 is configured to produce a display with an extent of 20 mm by 20 mm.

[0105] The microLED array 21 on the microLED structure 20 has a pitch of 130 pm making it possible to obtain a resolution of the order of 195 ppi (in English “pixels per inch” or in French “pixels per inch”) or 77 pixels per cm.

[0106] The number of microLEDs in the microLED structure 20 may be 160 x 160 x 3 or 76,800, the multiplication by 3 corresponding to the three colors to produce the display.

[0107] In the example which has just been described, the microLEDs are deposited directly on the upper glass 14.

[0108] Alternatively, as can be seen in [Fig.5], in an exemplary embodiment of the invention, the microLED structure 20 comprises a substrate 28 in the form of a transparent glass pellet, and the microLEDs are arranged on one face of this substrate 28. Only then is the substrate 28 with the microLEDs assembled with the upper glass 14.

[0109] The microLED structure 20, in particular the substrate, has a polygonal periphery, for example rectangular or square.

[0110] Alternatively, the rim may be round or oval.

[0111] The microLED structure 20 is placed on the TFT-LCD assembly 2 with the network of microLED 21 opposite this external face 6 of the TFT-LCD assembly 2.

[0112] The substrate 28 of the microLED structure 20 is then oriented opposite the TFT-LCD assembly 2.

[0113] The TFT-LCD assembly 2 comprises on its external face 6 of the upper glass 14, a front polarizer 30, in particular in the form of a film on this external face 6.

[0114] The polarizer 30 is glued to the upper glass 14 by an optical glue 32 or OC A (in English “Optical Clear Adhesive”).

[0115] The polarizer 30 has an opening into which the microLED structure 20 extends, as illustrated in [Fig.l].

[0116] In certain cases, the microLED array 21 is embedded in the optical glue layer 32.

[0117] The thickness of the optical glue layer 32 is sufficient to embed the microLEDs in its thickness, the thickness of the optical glue being between 20 and 250 μm.

[0118] This thickness of the glue 32 is adjusted according to the dimensions of the microLEDs.

[0119] The upper glass 14 has a thickness of between 100 pm and 300 pm.

[0120] The backlighting structure 9 is placed opposite the lower glass 17 of TFT-LCD assembly 2.

[0121] The microLEDs occupy, for example, approximately 25% of the total surface area of ​​the microLED structure 20.

[0122] The microLED structure 20 has a slight overhang on the surface of the TFT-LCD assembly 2 so that the microLED structure 20 is sensitive to touch by a person.

[0123] In a variant illustrated in [Fig.6], the polarizer 30 even extends over the microLED structure 20. An optical glue 39 is provided between the upper glass 14 and the polarizer 30, the microLEDs being embedded in this layer of glue 39.

[0124] In this case, the light from the microLED structure 20 is polarized, and this configuration is suitable only with microLEDs of smaller dimensions.

Claims

Claims

1. Combined system (1) forming a screen, comprising: - an assembly (2) of the TFT-LCD type, comprising an upper glass supporting a color filter and a lower glass supporting a thin-film transistor (TFT) structure, the lower glass being configured to be placed on the side of a backlighting structure, this TFT-LCD assembly having an active display area (3) and a passive area (4), - a camera (10) placed on the side of the lower glass of the TFT-LCD assembly, opposite the passive area (4), this camera being configured to capture useful radiation, for example visible light, and the active display area of ​​the TFT-LCD assembly being substantially obstructive for the useful radiation of the camera and the passive area being configured to let the useful radiation of the camera pass, - a microLED structure (20) placed on an external face of the upper glass of the TFT-LCD assembly,at the right of the passive zone, so that the camera can capture the useful radiation having passed through the passive zone and the microLED structure (20).,

2. Combined system (1) according to the preceding claim, wherein the passive area (4) is devoid of transistor used in the TFT-LCD function, while the active display area (3) comprises transistors of the TFT LCD function.

3. Combined system (1) according to one of the preceding claims, in which the TFT-LCD assembly (2) has, in the passive zone, a polarization of the liquid crystal layer to allow the passage of useful radiation towards the camera.

4. Combined system (1) according to one of the preceding claims, wherein the microLED structure (20) comprises an array of microLEDs (21).

5. Combined system (1) according to one of the preceding claims, wherein the microLED structure (20) is semi-transparent for the useful radiation of the camera.

6. Combined system (1) according to the preceding claim, wherein the microLED structure (20) comprises an array of microLEDs which are arranged on one face of the microLED structure leaving free gaps between the microLEDs.

7. Combined system (1) according to one of the preceding claims, wherein the microLED structure (20) is configured to be driven independently of the TFT-LCD assembly for the displays.

8. Combined system (1) according to one of claims 1 to 6, in which the microLED structure (20) is configured to be driven by drive electronics of the TFT-LCD assembly.

9. Combined system (1) according to one of the preceding claims, wherein the combined system (1) is configured to synchronize the acquisition of the camera with the display of the microLED structure (20), in particular so as to avoid an acquisition of the camera at the same time as the display by the microLED structure.

10. Combined system (1) according to one of the preceding claims, in which the microLED array (21) on the microLED structure has a pitch of 130 pm making it possible to obtain a resolution of the order of 195 ppi or 77 pixels per cm.

11. Combined system (1) according to one of the preceding claims, in which the TFT-LCD assembly (2) comprises on its external face a polarizer, in particular in the form of a layer on this external face, the polarizer being bonded to an upper glass of the TFT-LCD assembly by an optical glue (32) and the microLEDs are embedded in the layer of optical glue (32).

12. Combined system (1) according to one of the preceding claims, wherein the microLEDs occupy approximately 25% of the total area of ​​the microLED structure (20).

13. Combined system (1) according to one of the preceding claims, wherein the microLED structure (20) has a slight overhang on the surface of the TFT-LCD assembly so that the microLED structure (20) is sensitive to touch by a person.

14. Combined system (1) according to one of the preceding claims, in which the TFT-LCD type assembly may comprise a color filter (18) extending into the active display area and outside the passive area (4).

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