Display device having an IR camera for a vehicle

Abstract

The invention relates to a display device (10) for a vehicle, comprising an LCD display (12) and a liquid crystal layer, on the rear face of which a (second) polarization layer or a polarization filter with a rough anti-glare surface (74) is located. Backlight of a backlighting unit (24) emerges from the light-emitting side of said unit and backlights the LCD display (12). In addition, an IR light source also radiates IR radiation into the LCD display (12), the IR radiation likewise penetrating the polarization film on the rear face. The IR radiation which thus reaches the region in front of the LCD display (12) is reflected by an object possibly present there, such as the face of a person located in front of the display device for example, and reaches an IR camera (32) through the LCD display (12) and optionally the backlighting unit (24). The rough anti-glare surface (74) of the rear-face polarization film of the LCD display (12) impairs the reflected IR radiation, and for this reason the rear face of the rear-face polarization film has a local sub-region which is free of the rough anti-glare surface (74) and lies on the optical axis (21) of the IR camera (32).

Description

[0001] Display device with infrared camera for one vehicle

[0002] The invention relates to a display device with an IR camera for a vehicle and in particular to a display device in which the IR camera is arranged behind the display surface of the display or, in other words, behind that surface of the display device which is enclosed by a frame which typically surrounds the display.

[0003] To increase vehicle safety, it has long been known to monitor the vehicle interior for potential safety risks. In particular, it is known to capture the driver's face in order to detect potential driver fatigue early on, for example, by observing eyelid movements, and then issue an appropriate warning signal.

[0004] For various reasons, the cameras used for this purpose should be integrated into display units mounted in the instrument panel. The frame that typically surrounds such displays is generally suitable for housing the cameras. However, for aesthetic reasons, the trend is increasingly towards making these frames as narrow as possible, leaving insufficient space to accommodate the camera. The same applies to the edge of the display itself, which is typically black.

[0005] It is known, for example, to arrange IR cameras behind the display and behind its backlighting unit. An example of such a concept is described in EP-A-3 608 147. However, in this known system, two different stacks of "optical films" are used for the IR camera on the one hand and the actual display area on the other, which can be undesirable.

[0006] Various display devices with IR cameras are known from DE-A-10 2019 212 306, DE-A-10 2017 217 193, DE-A-10 2017 217 916, DE-A-10 2020 129 547, DE-A-10 2010 033 649, US-A-2023 / 0251416, US-B-11 340 491, JP-A-2022- 151913, CN-A-111240092, WO-A-2024 / 061891 and WO-A-2024 / 246124 (pre-filed and subsequently published).

[0007] Backlighting units for displays are described, for example, in DE-A-10 2017 217 916, DE-A-10 2020 202 917 and US-A-2022 / 0066265.

[0008] The object of the invention is to provide a display device with an IR camera for a vehicle in which the reflected IR radiation reaching the IR camera is not impaired by optical components of the display device that are advantageous for improving the backlighting of the display device.

[0009] To solve this problem, the invention proposes a display device for a vehicle, which is provided with an LCD display, which is provided with a cover plate having a display area, a liquid crystal layer having a front side facing the cover plate and a back side facing away from the front, a first polarization layer arranged on the front side of the liquid crystal layer, a second polarization layer arranged on the back side of the liquid crystal layer having a back side facing away from the liquid crystal layer, wherein the back side of the second polarization layer has a rough, non-reflective surface, a backlighting unit which is provided with a light-emitting side facing the back side of the second polarization layer for backlighting light, and several backlighting light sources for emitting backlighting light.at least one IR light source for emitting IR radiation into an area on and / or in front of the cover glass, an IR camera with an IR-sensitive radiation detection side for detecting IR radiation reflected on and / or in front of the cover glass of the LCD display, which travels along an optical axis, on which, among other things, the radiation detection side of the IR camera is also located, through the LCD display and the backlighting unit to the IR camera, and wherein the back of the second polarization layer has a local area lying on the optical axis in which the back of the second polarization layer is free of a rough surface structure and / or in which the rough antibiending surface of the back of the second polarization layer is smoothed.

[0010] According to the invention, the display device comprises an LCD display with a cover plate containing the display area, which is provided in a known manner with a liquid crystal layer arranged between a front-side first polarization layer and a rear-side second polarization layer. The two polarization layers are the polarization films typically found in LCD displays.

[0011] Facing the reverse side of the second polarization layer is a backlighting unit with a light-emitting side for backlighting and with multiple backlighting light sources for emitting backlighting light. Furthermore, the display device according to the invention has at least one IR light source for emitting IR radiation into an area on and / or in front of the cover plate. Reflected IR radiation from this area or from the cover plate passes through the LCD display and, if applicable, the backlighting unit to the radiation detection side of an IR camera, along an optical axis. This optical axis thus also passes through the second polarization layer, which, to improve the quality of the backlit information displayed on the screen, is typically provided with an anti-reflective surface having a rough structure.Such surfaces of back-side polarizing films for LCD displays are generally known (see, for example, KR-A-10 2013 0049202 and WO-A-2021 / 177169). They serve to prevent the formation of moiré effects. Furthermore, the known antibiending surface structures suppress back reflections of ambient light within the display.

[0012] While the rough surface structure is quite advantageous for the backlighting and does not impair it, it can be detrimental to reflected IR radiation that is intended to reach the IR camera, which in turn can be located inside or outside, i.e. e.g. below or next to, the backlighting unit.

[0013] Therefore, according to the invention, the back side of the second polarization layer is provided that, in a locally limited sub-region, it is free of rough surface structure or that the rough surface structure in this sub-region is smoothed, typically by applying a material. This local sub-region lies on the optical axis along which reflected IR radiation travels to the IR camera. The advantage of this approach is improved quality of the IR images captured by the IR camera.

[0014] In an advantageous embodiment of the invention, the surface structure of the back side of the second polarization layer in the local area can be smoothed by means of a material, in particular a resin, applied to the rough surface structure and transparent to the reflected IR radiation.

[0015] Alternatively, the rough surface structure of the back of the second polarization layer in the local area can be removed, in particular by means of a chemical and / or physical ablation process, especially by means of an ablation process using a plasma.

[0016] As an alternative to the aforementioned variants, the rough anti-glare surface can be formed from one side of a film placed on the back of the second polarization layer.

[0017] Typically, the backlighting units for LCD displays are provided with a diffuser plate that homogenizes and scatters the backlighting light. Such a diffuser plate or diffuser layer is preferably "neutral" with respect to IR radiation. An example of such an IR-neutral diffuser is described in US-A-2022 / 0991316. A display device with an IR-neutral diffuser is also described in WO-A-2024 / 061891, the contents of which are hereby incorporated by reference into the subject matter of the present application.

[0018] As an alternative to the diffuser plate described above, the backlighting unit can have an electrically controllable electro-optical diffuser plate that can be operated alternately in a first operating mode, in which the diffuser plate allows the backlighting light from the activated backlighting light sources to pass through with scattering, and in a second operating mode, in which the diffuser plate allows the IR radiation reaching the IR camera to pass through without scattering when the backlighting light sources are deactivated. Such an electro-optical diffuser plate is described, for example, in US-A-2015 / 0261384.

[0019] According to a further aspect of the invention, the display device is characterized in that the light-exit side of the backlighting unit is formed by a backlight-scattering diffuser plate which has a circumferential outer edge, that the diffuser plate has a recess open to a section of its outer edge in which or with which a light guide plate is arranged in alignment, that the light guide plate has a light entry edge exposed to the outer edge of the diffuser plate and a light exit side facing the rear of the display, and that the backlighting unit has further backlighting light sources for emitting backlighting light into the exposed light entry edge of the light guide plate, wherein the backlighting light from these backlighting light sources exits from the light exit side of the light guide plate to backlight the display.and that the light guide plate and the recess of the diffuser plate are arranged on the optical axis. According to this aspect of the invention, it is therefore provided to use a direct backlighting unit for the display, in which the backlighting light sources emit their light directly towards the display. The backlighting light sources are located in a reflector-containing area of ​​the backlighting unit. Typically, such backlighting concepts require a diffuser plate between the backlighting light sources and the LCD display. The diffuser plate forms the light-exit side of the backlighting unit, which can also be formed by one of several so-called BEF or DBEF layers of the backlighting unit.

[0020] While the diffuser plate, in particular, ensures the scattering and thus homogenization of the backlighting light, and therefore improved illumination of the display, such a measure is somewhat disadvantageous if, as provided for in the invention, an IR camera is arranged behind or below the display, which receives IR light emitted by the display device after a potential reflection in the area in front of or on the display surface. This is because this reflected IR radiation is also negatively affected by the diffuser plate.

[0021] According to the aspect of the invention described here, it is therefore provided that the IR camera is arranged with its optical axis aligned with an edge recess of the diffuser plate (hereinafter also referred to as the diffuser layer). However, this would mean that backlighting light penetrating this edge recess would no longer be scattered, or that a different backlighting intensity would be established in the display area aligned with this recess than in the rest of the display area.

[0022] According to this aspect of the invention, the edge recess is now filled by a light guide plate, which is supplied with backlighting light according to the Edge Lit system. This backlighting light then reaches the display via the side of the light guide plate facing the display, i.e., via its light-emitting side. This ensures homogeneous backlighting of the display, even in the area of ​​the recess. Like the display, the light guide plate is transparent to IR radiation, so that IR radiation reflected from the area in front of the display surface reaches the IR camera unhindered.

[0023] The backlighting unit therefore has two types of light sources (typically in the form of LEDs) that emit (backlighting) light in the visible wavelength range: on the one hand, the direct-radiating light sources, and on the other hand, the additional light sources that enter the light guide plate via the light entry edge and exit via the light exit side.

[0024] According to a further alternative aspect of the invention, it is characterized in that the light-emitting side of the backlighting unit is formed by a diffuser plate having a circumferential outer edge, that the diffuser plate has light-refracting and / or light-deflecting light distribution homogenization properties on its upper and / or lower surface in the form of imprints and / or surface structures, and / or has light-refracting and / or light-deflecting light distribution homogenization properties within the diffuser plate, that these light distribution homogenization properties gradually decrease within an outer edge region adjacent to the outer edge of the diffuser plate, and that in the outer edge region a partial area bounded to the outer edge region of the diffuser plate by an exposed outer edge section of the diffuser plate is free orThe invention is virtually free of these light distribution homogenization properties because the backlighting unit has additional backlighting light sources for emitting backlighting light into the exposed outer edge section of the diffuser plate's outer edge region. This backlighting light emerges from the section of the diffuser plate associated with the outer edge region of the diffuser plate to illuminate the display, and the diffuser plate's outer edge region is arranged on the optical axis. In this second alternative aspect of the invention, the area of ​​the diffuser layer free of diffuser properties is formed as an integral part of the diffuser layer.The zone of the diffuser layer that is essentially free of diffuser properties is achieved by gradually decreasing the density of the light distribution homogenization properties used in the form of imprints and / or surface structures and / or light-refracting and / or light-deflectoring particles located within the diffuser layer towards this zone. The area of ​​the diffuser layer that is aligned with the IR camera and is therefore intended to transmit IR radiation without scattering thus exhibits no, or essentially no, light-refracting and / or light-deflectoring light distribution homogenization properties in the form of imprints and / or surface structures and / or particles. These light distribution homogenization properties then gradually increase towards the remaining area of ​​the diffuser layer.

[0025] Typically, the light guide plate should be light-reflecting on its side surfaces adjacent to the diffuser layer, for example by having reflector layers.

[0026] According to an alternative third aspect of the invention, the display device is characterized in that the light-exit side of the backlighting unit is formed by a backlight-scattering diffuser plate having a circumferential outer edge, that the diffuser plate has a recess on all sides spaced from the outer edge of the diffuser plate, in which, or aligned with, a light guide plate is arranged with a light-exit side facing the rear of the display and a light-intake side facing away from it for receiving backlighting light from backlighting light sources of the backlighting unit, and that the light guide plate and the recess of the diffuser plate are arranged on the optical axis. According to this third aspect of the invention, the recess of the diffuser layer is advantageously located within the diffuser layer and is surrounded by the material of the diffuser layer.The recess is therefore spaced on all sides from the outer edge of the diffuser layer. Within this recess is a light guide plate, positioned on the optical axis of the IR camera. The underside of the light guide plate, facing away from the display, forms its light entry side and receives visible light from the light sources of the backlighting unit. This light exits the light guide plate through its light exit side.

[0027] In this third aspect of the invention, light sources from the backlighting unit are used to supply light to the light guide plate, with their optical axes pointing directly towards the display. The light guide plate is transparent to IR radiation, so that reflected IR radiation from the area in front of the display surface reaches the IR camera essentially undisturbed.

[0028] Furthermore, in this third aspect of the invention, it can be said that the light guide plate adjacent to the diffuser layer has light-reflecting side surfaces for reflecting light emitted into the light guide plate by the other light sources.

[0029] As mentioned above, the light from the backlighting unit can be fed into the light guide plate by the backlighting unit's light sources, which shine directly towards the display. Advantageously, these light sources are arranged at an angle. They are conveniently located around the camera and illuminate the light guide plate from below.

[0030] Alternatively, the light guide plate can have downward-facing light guide projections pointing towards the light sources of the backlighting unit, with at least one such projection being sufficient. The light guide projection can be in the form of a ring structure and has a light entry side facing away from the light guide plate, which in turn is opposite one or more light sources of the backlighting unit that emit visible light.According to a fourth aspect of the invention, the display device is characterized in that the light-emitting side of the backlighting unit is formed by a diffuser plate having a circumferential outer edge, that the diffuser plate has light-refracting and / or light-deflecting light distribution homogenization properties on its upper and / or lower surface in the form of imprints and / or surface structures, and / or has light-refracting and / or light-deflecting light distribution homogenization properties within the diffuser plate, that these light distribution homogenization properties gradually decrease within an inner area of ​​the diffuser plate which has a distance on all sides from the outer edge of the diffuser plate, and are free or restricted in a partial area lying within this area.The fact that the area is almost free from these light distribution homogenization properties is due to the fact that backlighting light sources of the backlighting unit are arranged in alignment with the sub-area and that the sub-area of ​​the diffuser plate is arranged on the optical axis.

[0031] According to this fourth aspect of the display device according to the invention, the area of ​​the diffuser layer that is essentially free of diffuser properties, i.e., light scattering properties, is not located in the edge region of the diffuser layer but within this diffuser layer, and is thus surrounded on all sides by areas of the diffuser layer with diffuser properties.

[0032] In the fourth variant of the invention, the area of ​​the diffuser layer that is essentially free of light distribution homogenization properties is achieved, in the same way as in the second variant, by gradually decreasing the density of imprints, surface structures or particles providing corresponding light distribution homogenization properties.

[0033] According to a fifth aspect of the invention, the display device is characterized in that the light-emitting side of the backlighting unit is formed by a diffuser plate, that the diffuser plate has a recess in which a carrier element with OLEDs and / or micro-LEDs for emitting visible backlighting light towards the rear of the display is arranged, and that the recess of the diffuser plate and thus the carrier element is arranged on the optical axis.

[0034] According to this aspect of the invention, the recess in the diffuser layer is filled by a carrier layer with OLEDs and / or micro-LEDs, which in turn emit light directly towards the back of the display.

[0035] Regarding the design of the backlight unit, it can be advantageous to include reflectors in addition to the light sources that shine directly onto the back of the display. Both the light sources and any reflectors are typically arranged in a 2D matrix structure. Each reflector contains at least one light source for visible light. Such backlight units are also known as Matrix Direct Backlight Units.

[0036] In addition to the foregoing, and applicable to all aspects and embodiments of the invention, the backlighting unit can also be equipped with a light dimming function for selective local dimming of the backlighting light, as described in WO-A-2022 / 029239. The content of that document is hereby incorporated by reference into the subject matter of the present disclosure.

[0037] For all the aforementioned aspects and embodiments of the display device according to the invention, in addition to the diffuser layer with its recess between the display and the backlighting unit, an optical brightness enhancement layer and / or an optical transreflective polarization layer can be arranged, which in turn have recesses that are aligned with the recess of the diffuser layer. Suitable additional layers include optical layers known particularly in displays with backlighting directly projected onto their reverse side, such as a brightness enhancement layer (also known in the art as BEF, which is an acronym for the designation of a commercially available optical film) or a transreflective polarization layer (known in the art as DBEF, which is also an acronym for the designation of a commercially available optical film).

[0038] According to a final aspect of the invention, it is alternatively provided that the IR camera is arranged in one of the reflectors of the backlighting unit.

[0039] According to this aspect of the invention, a micro-IR camera is used, which is typically arranged together with at least one light source of the backlighting unit within one of the reflectors of the backlighting unit.

[0040] According to this aspect of the invention, the display device can advantageously have a diffuser layer structure as described above in connection with the other aspects. All configurations of the diffuser layer, as previously described, are therefore possible for use in the display device according to the sixth aspect of the invention.

[0041] In a further advantageous embodiment of the invention according to each of the aforementioned variants, the display device can have a first mirror reflection polarization film arranged on the back of the display or opposite it for reflecting visible backlighting light, the polarization of which differs from the polarization direction of a rear polarization filter of the display, wherein backlighting light reflected from the first mirror reflection polarization film can be reflected by the reflectors of the backlighting unit back towards the first mirror reflection polarization film by changing its polarization direction.

[0042] As mentioned previously, such mirror-reflecting polarizing filters are known under the keywords BEF (Brightness Enhancement Film), DBEF (Dual Brightness Enhancement Film), and ALCF (Advanced Light Control Film) as optical films or layers from companies like 3M. All these systems and components increase the light output for backlighting the display.

[0043] In a further advantageous embodiment of the invention, it can be provided that the first mirror reflection polarization film also reflects IR light whose polarization differs from the polarization direction of the rear polarization filter of the display, and that an IR reflection film is arranged below the IR light sources for the reflection of IR light reflected by the first mirror reflection polarization film while changing the polarization direction.

[0044] A further embodiment of the invention is characterized by a second mirror reflection polarization film arranged below the backlighting unit for the reflection of IR light, the polarization of which differs from the polarization direction of a rear polarization filter of the display, and an IR reflection film arranged below the IR light sources for the reflection of IR light reflected by the second mirror reflection polarization film with a change in polarization direction.

[0045] Typically, IR light sources emit NIR light, and therefore an IR camera is a NIR camera. The IR camera is either two-dimensional or a line scan camera and may be equipped with an optical lens.

[0046] The display surface can also be advantageously used for inputting commands by touching the display surface, if a touch sensor is integrated accordingly, such as can be implemented using a touch panel.

[0047] As explained above, the IR light sources are also expediently part of the backlighting unit. They, too, therefore emit their IR light directly towards the display and are, for example, positioned below the diffuser layer's cutout. However, it would also be possible, in principle, to position the IR light sources at the edge of the display, or below and / or within its typical bezel.

[0048] In addition to the diffuser layer and any further optical layers already mentioned above, the display device according to the variants with a recess in the diffuser layer can have a further (second) diffuser layer, which also has a recess which in turn aligns with the recess of the diffuser layer or with the recesses of the optional optical layers, wherein the recess of this further diffuser layer with its edge region covers the transition from the light guide plate to the diffuser layer.

[0049] In backlit units with light sources emitting light directly from the rear, a problem sometimes arises that this directly emitted light can only be inadequately homogenized with a single diffuser layer. Therefore, approaches to using multiple diffuser layers or "thicker" diffuser layers already exist in the prior art. An advantage of using multiple diffuser layers (for example, two diffuser layers) is that, in addition to the diffuser layer according to the invention, a further diffuser layer is used that is neutral to IR radiation, i.e., transparent. Such diffuser layers are described, for example, in US-A-2022 / 0091316. There, the aforementioned IR-neutral diffuser layer is described as a "High Infrared Light Clarity Diffuser."

[0050] In a further advantageous embodiment of the invention, the at least one IR light source can be arranged outside the display area, for example, within a frame surrounding the display. Alternatively, the at least one IR light source can also be arranged below the diffuser layer, below the backlighting unit. An arrangement of the at least one IR light source within the backlighting unit is also possible. Finally, if the at least one IR light source is not arranged outside the display area, it can be aligned with the zone of the diffuser layer that is essentially free of diffuser properties, i.e., light distribution homogenization properties.

[0051] The invention is explained in more detail below with reference to various exemplary embodiments and the drawings. Specifically, the drawings show:

[0052] Fig. 1 shows an example of the application of the display device according to an embodiment of the invention.

[0053] Fig. 2 schematically shows the structure and arrangement of various optical layers of the display device with LCD display and backlighting unit.

[0054] Fig. 3 shows a schematic side view of the main components essential to the invention of a first embodiment of a display device,

[0055] Fig. 4 shows a top view of the display device according to Fig. 1 in the direction of arrow II,

[0056] Fig. 5 shows a schematic side view of the main components essential to the invention of a second embodiment of a display device,

[0057] Fig. 6 shows a schematic side view of the main components essential to the invention of a third embodiment of a display device,

[0058] Fig. 7 is a top view of the display device according to Fig. 5 or Fig. 6 or Fig. 8 in the direction of arrow II, Fig. 8 is a schematic side view of the main components essential for the invention of a fourth embodiment of a display device,

[0059] Fig. 9 shows a schematic side view of the main components essential to the invention of a further embodiment of a display device and

[0060] Fig. 10 shows a top view of the reflector of the backlighting unit of the embodiment according to Fig. 9, in which, in addition to at least one light source, the IR camera is also arranged as a mini-camera.

[0061] Figs. 11 and 12 show two views (side and section views) of a further embodiment in which the area of ​​the diffuser layer that is essentially free of light distribution homogenization properties is formed integrally with it, i.e., unlike the rest of the diffuser layer, it has no light distribution homogenization properties, and

[0062] Figs. 13 to 15 show three variants of a first diffuser layer with gradually decreasing light diffusion properties towards the part of the layer that is free or almost free of light distribution homogenization properties.

[0063] The figures show several embodiments of a display device according to the invention. If the individual embodiments include elements that are identical in construction or function, they are provided with the same reference numerals in the figures.

[0064] Fig. 1 shows an application example for the display device 10 according to the invention with an IR camera 32 arranged behind it. In this embodiment, both are arranged in the instrument panel 11 of a vehicle, with the IR camera 32 directed towards the driver 13. The information extracted from the camera image is application-specific and generally known, which is why it is not necessary to discuss it in more detail within the scope of this invention.

[0065] Fig. 2 shows the essential aspect of the invention relating to the rear side of the rear polarization layer of the LCD display facing the backlighting unit.

[0066] Fig. 2 shows in more detail the layer structure of the display device 10, in which the display 12 has a cover disc 15 which forms the front 14 of the display 12 and has the display area 16 of the display 12.

[0067] The LCD display 12 has a liquid layer 68, on the front side 69 of which a first polarization layer 70 is arranged. A second polarization layer 71 is arranged on the back side 72 of the liquid layer 68. Such polarization layers are generally known in LCD displays, which is why these polarization filters will not be discussed further here.

[0068] A touch panel 17 may optionally be arranged between the first polarization layer 70 and the cover plate 15.

[0069] A backlighting unit 24 with backlighting light sources 28 provides backlighting for the display 12, a concept that is generally known. In this embodiment, the backlighting light sources 28 operate according to the edge-lit principle. Equally, the backlighting light sources 28 could also emit their light directly onto the rear surface 18 of the display 12 (direct-lit principle). In that case, the backlighting light sources 28 would be arranged within reflectors, which will be described further below using additional embodiments.

[0070] The display device 10 serves not only to display information and input commands (only if a touch panel is present), but also to detect and photograph objects in the area 36 in front of the cover plate 15 or even on the cover plate 15. This detection is carried out using infrared radiation emitted by IR light sources 34. In this embodiment, the IR light sources 34 are arranged below the backlighting unit 24. However, they can also be a direct integral part of the backlighting unit 24.

[0071] The IR light sources 34 emit IR radiation through the display 12 into the area 36 in front of the display, from which reflected IR radiation passes back through the display 12 to an IR camera 32. The reflected IR radiation passes through the LCD display and the backlighting unit 24 along an optical axis (see the dashed line with reference numeral 21).

[0072] The rear-side second polarization layer 71 is arranged with its back side facing away from the liquid crystal layer 28 and its light-emitting side 25 of the backlighting unit 24. To improve the display quality of the display 12, this back side 73 of the second polarization layer 71, which also forms the back of the display 12, has an anti-reflective surface 74. This anti-reflective surface 74 has a roughness that is advantageous for the backlighting of the display 12, but has certain disadvantages when it comes to the reflected IR radiation penetrating the display 12 towards the IR camera 32. In this case, the rough anti-reflective surface 74 impairs the reflected IR radiation.

[0073] For this reason, according to the invention, a local area 76 is provided on the back side 73 of the second polarization layer 71 in which the back side 73 of the second polarization layer 71 is smoothed. The smoothed surface within the local partial area 76 is marked with reference numeral 78 in Fig. 2.

[0074] In this way, it is ensured that the anti-reflective surface 74 fulfills its function with regard to the backlighting light and has no adverse effects on the reflected IR radiation. Various embodiments of the invention are described below with reference to Figures 3 to 15, in which the display device, in addition to the previously described configuration of the rear side 18 of the display 12, i.e., the surface 74 of the rear polarization layer 71, also has additional advantageous properties to further improve the quality of the IR radiation reaching the IR camera 32. These improvements relate to specific configurations of the diffuser plate or the diffuser layer, or also to other optically effective layers on the light-exit side 25 of the backlighting unit 24.In the aforementioned figures, the special design of the back 74 of the second polarization layer 71 within the box representing the display 12 is symbolized by a jagged line with a smooth line in the local sub-area 76.

[0075] Fig. 3 shows a first embodiment of a display device 10a with an IR camera. The display device 10a has a backlit display 12 based, for example, on LC technology, which has a front 14 with a display area 16 and a back 18. Facing the back 18 is an optical stack 20, which has at least a first diffuser layer 22. Typically, the optical stack 20 is also provided with further optical layers, such as a BEF layer (brightness enhancement film) and / or a DBEF layer and / or a DLRP layer (direct light reflective polarizer). Such optical layers for optimizing the backlighting of LC displays by backlight light sources shining directly onto the LC display 12 are generally known in the prior art, and reference is made to these known layers in this respect.

[0076] Below the optical stack 20 is a backlighting unit 24, which has a carrier element 26 in the form of, for example, a circuit board, on which backlighting light sources 28, typically in the form of LEDs, and reflectors 30 are arranged. An IR camera 32 is also located on the carrier element 26. Furthermore, IR light sources 34 may also be located on the carrier element 26. IR light is emitted into the area 36 in front of the display surface 16 by the optical stack 20 and by the display 12 (the latter when the IR light sources 34 are arranged below the display 12). If an object is located in this area, for example the face of a person looking at the display device 10a, the IR light is reflected and reaches the IR camera 32. If the reflected light had to pass through the optical stack 20, there would be a risk of distortion of the IR light, so that the IR camera 32 would only capture inferior camera images.

[0077] Therefore, according to the first to fourth embodiments (Figs. 1 to 8), the optical stack 20 is provided with a through-opening 38, which is represented, for example, as a recess 40 in the first diffuser layer 22. This recess 40 is shown in Fig. 4 as an edge recess of the first diffuser layer 22. The first diffuser layer 22 has a circumferential boundary edge 42, which within one of its sections is formed by the exposed (light entry) edge 43 of a light guide plate 44 within this section. The light guide plate 44 serves to provide backlighting for the display 12 within the through-opening 38 of the optical stack 20.For this purpose, the backlighting to be realized in this area is achieved by additional light sources 46 for visible light arranged laterally to the aforementioned light entry edge 43 of the light guide plate 44, which shine their light into the opposite light entry edge 43, whereby this light is emitted through the light exit side 48 of the light guide plate 44 and thus from the top 23 de in the direction of the display 12. Unlike the optical elements of the optical stack 20, the light guide plate 44 does not distort reflected IR light coming from the area 36, ​​so that the IR camera 32 arranged in line with the light guide plate 44 receives the reflected IR light undistorted or substantially undistorted.

[0078] The light guide plate 44 can be designed to reflect light on its side surfaces 50 adjacent to the first diffuser layer 22. Figure 4 shows by way of example the positions at which the IR light sources 34 can be arranged within the display device 10a. One variant of the arrangement of these IR light sources is that they are positioned outside the optical stack 20, for example in the edge region 52 and thus within a frame 54 of the display device 10a. Alternatively, as already described above, they can be part of the backlighting unit 24, and can be arranged either below the optical stack 20 or below the light guide plate 44.

[0079] The optical stack 20 expediently includes a further diffuser layer 56, which also has a recess 58 that covers the transition 60 of the light guide plate 44 to the first diffuser layer 22 or to the optical stack 20 in its edge region. This is indicated in Fig. 3.

[0080] The display device 10b according to Fig. 5 differs from the embodiment according to Fig. 3 in that the light guide plate 44 is now illuminated from below, i.e., not from the edge, by light sources 28 of the support element 26 that emit visible light. For this purpose, the light guide plate 44 can advantageously have light guide projections 64 on its underside light entry side 62, the light entry side(s) 66 of which are opposite light sources 28 for visible light, which exits via the light exit side 48 of the light guide plate 44 in the direction of the display 12. The IR camera 32 is located below the light guide plate 44.

[0081] In the exemplary embodiment of the display device 10c of Fig. 6, the illumination of the light guide plate 44 is carried out by light sources 28 of the carrier element 26 which are advantageously slightly inclined for this purpose.

[0082] In both the embodiment of Fig. 5 and that of Fig. 6, the recess in the optical stack 20 can be completely surrounded by material from the layers of the optical stack 20 (see Fig. 7). This is because, in the embodiments of Figs. 5 and 6, the light guide plate 44 is not edge-lit with backlighting, as is the case in the embodiment of Figs. 3 and 4. Fig. 8 shows a further embodiment of a display device according to the invention, in which a carrier element 67 is arranged in the through-opening 38 in the optical stack 20, which is provided with OLEDs or micro-LEDs (both not shown). The transparency for IR light through the carrier element 67 with the OLEDs or micro-LEDs is determined by the degree of light transmission.Micro-LEDs ensure that the IR camera 32, which is located below this support element 67 on the support element 26 of the backlighting unit 24 (which also applies to all other embodiments of the display device according to the invention, as shown in the figures), receives reflected IR light essentially undisturbed.

[0083] Figures 9 and 10 show an additional embodiment of a display device 10e according to the invention. In this embodiment, the optical stack 20 between the backlighting unit 24 and the display 12 has no through-opening. The IR camera 32, together with one or more light sources 28 of the carrier element 26, is located within a reflector 30. This is shown in Figure 10. Alternatively, the optical stack 20 can also have the configuration according to one of the preceding or subsequently described embodiments.

[0084] Figures 11 and 12 show a further embodiment of the invention. The construction of the display device 1Of shown in these figures is similar to that of the display device 10a in Figures 3 and 4, so that essentially the reference numerals used there are also found in Figures 11 and 12.

[0085] The difference between the display device lOf and that of Figures 3 and 4 lies in the structure of the first diffuser layer 22'. This diffuser layer 22' exhibits light diffusion properties, i.e., light distribution homogenization properties, in the form of refractive and / or deflecting properties, which can be realized, for example, by printing on the plastic layer, a surface structure of the plastic layer, and / or in the form of particles within the plastic layer. In one area, the diffuser layer 22' exhibits no or substantially no such refractive or deflecting properties and is therefore "neutral," particularly with regard to reflected IR light. This area is designated by reference numeral 44' in Figures 11 and 12.In this embodiment, this is located in an outer edge region 45, which, within the boundary edge 42 of the first diffuser layer 22', has an exposed outer edge section 43' as a light entry edge for the sub-region 44'. As in the embodiment of the display device 10a, the backlighting light from the (edge-lit) light sources 46 of the backlighting unit 24 now shines into this light entry edge of the sub-region 44'.

[0086] The sub-region 44', which is free or essentially free of light diffusion properties, is formed by the gradual decrease in light diffusion properties from the rest of the first diffuser layer 22'. This is indicated in Figures 11 and 12 at 47' by graphically showing that the density of the points representing the degree of light diffusion properties gradually decreases until finally no light diffusion properties exist, or essentially no light diffusion properties exist, in sub-region 44'.

[0087] The advantage of the design of the diffuser layer 22 according to Figs. 11 and 12 lies in the simpler construction and assembly of the display device.

[0088] Figures 13 to 15 show different possibilities for influencing the degree of light diffusion properties of the first diffuser layer 22'.

[0089] According to Fig. 13, the light diffusion properties of the first diffuser layer 22 are achieved by particles within the diffuser layer 22'. By gradually decreasing the particle density towards the sub-region 44' and by eliminating or not including such particles in the sub-region 44', this sub-region 44' can ultimately be free of light diffusion properties. Fig. 14 shows an example in which the volume of the first diffuser layer 22' is free of light-refracting or light-deflectoring particles throughout the entire area where the gradual decrease in light diffusion properties occurs, including the sub-region 44'. The gradual decrease outside the sub-region 44', which borders this sub-region 44', is achieved by a gradually decreasing density printing on the surface (top and bottom) of the diffuser layer 22' or by a gradual decrease in the density of any particles that may be present.also additional surface structures providing light-refracting or light-deflectoring properties of the first diffuser layer 22'.

[0090] Finally, Fig. 15 shows that the light diffusion properties of the first diffuser layer 22' are achieved by printing or surface structuring in those areas where light diffusion properties are desired. Towards the sub-area 44', there is therefore a gradually decreasing density of printing or surface structuring in area 47'.

[0091] REFERENCE MARK LIST

[0092] 10 Display device 10a Display device 10b Display device 10c Display device lOd Display device lOe Display device lOf Display device 11 Instrument panel 12 Display 13 Driver 14 Front of display 15 Cover plate 16 Display area 17 Touch panel 18 Back of display 20 Optical stack 21 Optical axis of the IR reflection radiation or IR camera 22 First diffuser layer / diffuser plate of the optical stack 22' First diffuser layer / diffuser plate of the optical stack 23 Top side of the first diffuser layer 23' Top side of the first diffuser layer 24 Backlighting unit 25 Light exit side of the backlighting unit 26 Carrier element (circuit board) of the backlighting unit 28 Backlighting light sources 30 Reflectors of the backlighting unit 32 IR camera 33 Radiation detection side of the IR camera 34 IR light sources 36 area in front of the display

[0093] 38 Through-hole in the optical stack 40 Recess in the first diffuser layer Boundary edge of the first diffuser layer or of the optical stack

[0094] Light entry edge of the light guide plate ' Outer edge section as light entry edge for the sub-area which is essentially free of light diffusion properties

[0095] Light guide plate ' partial area, the first diffuser layer, essentially free of light diffusion properties

[0096] Outer edge area with sub-area 44' further light sources of the backlighting unit ' gradually decreasing density of the light diffusion properties light exit side

[0097] Side surfaces of the light guide plate

[0098] Edge area of ​​the display device

[0099] Frame of the display with an additional diffuser layer

[0100] Recess of the further diffuser layer

[0101] Transition of the light guide plate to the first diffuser layer or to the optical stack; underside of the diffuser layer / diffuser plate; light guide projection

[0102] Light entry side of the light guide projection

[0103] Carrier element with OLEDs or micro-LEDs

[0104] Liquid crystal layer

[0105] Front side of the liquid crystal layer: first polarization layer / first polarization filter; second polarization layer / second polarization filter

[0106] back side of the liquid crystal layer

[0107] Back side of the second polarizing layer: rough, anti-stick surface; local area of ​​the back side of the second polarizing layer: smooth surface in the local area

Claims

REQUIREMENTS 1. Display device for a vehicle, comprising an LCD display (12) provided with a cover plate (15) having a display area (16), a liquid crystal layer (68) having a front (69) facing the cover plate (15) and a back (72) facing away from the front (69), a first polarization layer arranged on the front (69) of the liquid crystal layer (68), a second polarization layer arranged on the back (72) of the liquid crystal layer (68) having a back (72) facing away from the liquid crystal layer (68), wherein the back (73) of the second polarization layer has a rough anti-glare surface (74), a backlighting unit provided with a light emission side (25) facing the back (73) of the second polarization layer for backlighting light, and several backlighting light sources (28) for emitting backlighting light.at least one IR light source (38) for emitting IR radiation into an area on and / or in front of the cover glass (15), an IR camera (32) with an IR-sensitive radiation detection side (33) for detecting IR radiation reflected on and / or in front of the cover glass (15) of the LCD display (12), which travels along an optical axis, on which, among other things, the radiation detection side (33) of the IR camera (32) is also located, through the LCD display (12) and the backlighting unit to the IR camera (32), and wherein the back (73) of the second polarization layer has a local area lying on the optical axis in which the back of the second polarization layer is free of a rough surface structure and / or in which the rough antibiending surface (74) of the back (73) of the second polarization layer is smoothed.

2. Display device according to claim 1, characterized in that a material transparent to the reflected IR radiation, in particular a resin, is arranged in the local area on the surface structure to smooth the rough surface structure of the back (73) of the second polarization layer.

3. Display device according to claim 1, characterized in that the second polarization layer in the local area is free of rough surface structure and is therefore smooth or flat.

4. Display device according to claim 3, characterized in that the rough surface structure of the back side (73) of the second polarization layer in the local area is removed by means of a chemical and / or physical ablation process, in particular by means of an ablation process using a plasma, and is thus smooth or flat.

5. Display device according to one of claims 1 to 4, characterized in that the rough anti-reflective surface (74) is formed by one of the sides of a film arranged on the back (73) of the second polarization layer.

6. Display device according to one of claims 1 to 5, characterized in that the light exit side (25) of the backlighting unit (24) is formed by a diffuser plate which scatters the backlighting light of the backlighting light sources (28) and allows IR radiation reaching the IR camera to pass through without scattering.

7. Display device according to one of claims 1 to 5, characterized in that the light output side (25) of the backlighting unit (24) is formed by an electrically controllable electro-optic diffuser plate, which can be operated alternately in a first operating mode, in which the diffuser plate allows the backlighting light of activated backlighting light sources (28) to pass through by diffusing, and in a second operating mode. the diffuser plate allows IR radiation reaching the IR camera without scattering when backlighting light sources (28) are deactivated.

8. Display device according to one of claims 1 to 5, characterized in that the light emission side (48) of the backlighting unit (24) is formed by a backlighting diffuser plate (22) which has a circumferential outer edge (42), that the diffuser plate (22) has a recess (40) open to a section of its outer edge (42) in which or with which a light guide plate (44) is arranged in alignment, that the light guide plate (44) has a light entry edge (43) exposed to the outer edge of the diffuser plate (22) and a light emission side (48) facing the rear (18) of the display (12), and that the backlighting unit (24) has further backlighting light sources (46) for emitting backlighting light into the exposed light entry edge (43) of the light guide plate (44).wherein the backlighting light from these backlighting light sources for backlighting the display (12) exits from the light exit side (48) of the light guide plate (44), and that the light guide plate (44) and the recess (40) of the diffuser plate (22) are arranged on the optical axis.

9. Display device according to one of claims 1 to 5, characterized in that the light emission side (48) of the backlighting unit (24) is formed by a backlighting diffuser plate (22) which has a circumferential outer edge (42), that the diffuser plate (22) has a recess (40) on all sides having a distance to the outer edge of the diffuser plate (22), in which or with which a light guide plate (44) is arranged with a light emission side (48) facing the rear (18) of the display (12) and a light entry side (62) facing away from it for receiving backlighting light from backlighting light sources (28) of the backlighting unit (24), and that the light guide plate (44) and the recess (40) of the diffuser plate (22) are arranged on the optical axis.

10. Display device according to claim 8 or 9, characterized in that the light guide plate (44) has light-reflecting side surfaces (50) adjacent to the diffuser plate (22) for reflecting light emitted into the light guide plate (44) by the further light sources (46).

11. Display device according to claim 9 or according to claim 10, insofar as referring back to claim 9, characterized in that at least one light guide projection (64) with a light entry side (66) facing away from the light entry side of the light guide plate (44) projects from the light entry side of the light guide plate (44), which is opposite one or more backlight light sources (28) of the backlight unit (24) emitting backlight light.

12. Display device according to one of claims 1 to 5, characterized in that the light emission side (25) of the backlighting unit (24) is formed by a diffuser plate (22') having a circumferential outer edge (42), that the diffuser plate (22') has light-refracting and / or light-deflecting light distribution homogenization properties on its upper and / or lower surface in the form of imprints and / or surface structures, and / or has light-refracting and / or light-deflecting light distribution homogenization properties within the diffuser plate (22'), that these light distribution homogenization properties are located within an outer edge region adjacent to the outer edge (42) of the diffuser plate (22'). (45) gradually decrease and in the outer edge area (45) a partial area (44') limited to the outer edge area (42) of the diffuser plate (22') by an exposed outer edge section (43') of the diffuser plate (22') is free or almost free of these light distribution homogenization properties, so that the backlighting unit (24) provides further backlighting light sources (46) for emitting backlighting light into the exposed outer edge- section (43') of the sub-area (44') of the outer edge region (45) of the diffuser plate (22') that extends from the sub-area of ​​the diffuser plate (22') associated with the sub-area (44') of the outer edge region of the diffuser plate (22') to backlight the display (12), and that the sub-area (44') of the diffuser plate (22') is arranged on the optical axis.

13. Display device according to one of claims 1 to 5, characterized in that the light emission side (25) of the backlighting unit (24) is formed by a diffuser plate (22') having a circumferential outer edge (42), that the diffuser plate (22') has light-refracting and / or light-deflecting light distribution homogenization properties on its upper and / or lower surface in the form of imprints and / or surface structures, and / or has light-refracting and / or light-deflecting light distribution homogenization properties within the diffuser plate (22'), that these light distribution homogenization properties gradually decrease within an inner area (45) of the diffuser plate (22') which has a distance on all sides from the outer edge (42) of the diffuser plate (22') and are free or restricted in a partial area (44') located within this area (45).The part (44') is almost free of these light distribution homogenization properties because backlight light sources (28) of the backlight unit (24) are arranged in alignment with the sub-area (44') and because the sub-area (44') of the diffuser plate (22') is arranged on the optical axis.

14. Display device according to claim 13, characterized in that at least one light guide projection (64) with a light entry side (66) facing away from the light entry side of the backlighting unit (24) of the partial area free or almost free of light distribution homogenization properties projects from the light entry side of the partial area, which is opposite one or more visible light emitting light sources (28) of the backlighting unit (24).

15. Display device according to one of claims 1 to 5, characterized in that the light emission side (25) of the backlighting unit (24) is formed by a diffuser plate (22), that the diffuser plate (22) has a recess (40) in which a carrier element (67) with OLEDs and / or micro-LEDs for emitting visible backlighting light towards the rear of the display (12) is arranged, and that the recess of the diffuser plate (22) and thus the carrier element (67) is arranged on the optical axis.

16. Display device according to claim 15, characterized in that the backlighting unit (24) has a plurality of reflectors (30) held by a carrier element (26), each of which is assigned at least one light source (28) for visible light which is arranged inside the reflector (30).

17. Display device according to one of claims 8 to 16, characterized by a further diffuser layer (56) arranged above the diffuser plate (22, 22') and having a recess aligned with the recess (40) or the part (44') of the diffuser plate (22, 22') which is free or almost free of light distribution homogenization properties, with a border area that covers the interface between the light guide plate (44) or part (44') and the diffuser plate (22, 22').

18. Display device according to one of claims 8 to 17, characterized in that, in addition to the diffuser plate (22, 22') and / or, if present, to the further diffuser layer (56), an optical brightness enhancement layer and / or a transreflective polarization layer is arranged between the display (12) and the backlight unit (24), wherein each further optical layer has a recess and wherein all recesses in the aforementioned layers are connected to the recess (40) of the diffuser plate (22, 22') or to the layer without light distribution homogenization properties. or the part (44') of the diffuser plate (22, 22') that is almost free of light distribution homogenization properties.

19. Display device according to one of claims 1 to 18, characterized by a first mirror reflection polarization film arranged on the back (18) of the display (12) or opposite it for reflecting backlighting light, the polarization of which differs from the polarization direction of the second polarization layer of the display (12), wherein backlighting light reflected from the first mirror reflection polarization film by reflectors (30) or a reflector layer of the backlighting unit (24) can be reflected back towards the first mirror reflection polarization film by changing its polarization direction.

20. Display device according to claim 19, characterized in that the first mirror reflection polarization film also reflects IR light whose polarization differs from the polarization direction of the second polarization layer of the display (12), and that an IR reflection film is arranged below the IR light sources (34) for the reflection of IR light reflected by the first mirror reflection polarization film with a change in polarization direction.

21. Display device according to one of claims 1 to 20, characterized by a second mirror reflection polarization film arranged below the backlighting unit (24) for reflecting IR light whose polarization differs from the polarization direction of the second polarization layer of the display (12), and an IR reflection film arranged below the IR light sources (34) for reflecting IR light reflected by the second mirror reflection polarization film with a change in polarization direction.

22. Display device according to one of claims 1 to 21, characterized in that the at least one IR light source (34) emits NIR light and that the IR camera (32) is an NIR camera in the form of a line scan camera or a 2D camera.

23. Display device according to one of claims 1 to 22, characterized by a touch panel for manual input of commands by touching the cover glass (15) of the display (12).

24. Display device according to one of claims 1 to 23 characterized by an optical lens in front of the IR camera (32).

25. Display device according to one of claims 1 to 24, characterized by a diffuser layer transparent to IR radiation in the area between the light emission side (25) of the backlighting unit (24) and the second polarization layer of the display (12).

26. Display device according to one of claims 1 to 25, characterized in that the at least one IR light source (34) is arranged in an area laterally offset to the display (12), such as within a frame (54) surrounding the display (12).

27. Display device according to one of claims 1 to 26, characterized in that the backlighting light sources (28) for emitting backlighting light towards the diffuser plate (22, 22') are arranged below the diffuser plate (22, 22') and that the backlighting unit (24) has one or more reflectors (30) for reflecting backlighting light from the backlighting light sources (28) towards the diffuser plate (22, 22').

28. Display device according to one of claims 1 to 26, characterized in that the backlighting unit (24) has a light guide plate, that the light guide plate has a light-emitting side and a rear side facing away from the light-emitting side as well as a circumferential side connecting the light-emitting side and the rear side, that the light-emitting side of the light guide plate faces a diffuser plate (22, 22') of the backlighting unit (24), that the backlight light sources emit backlight light towards at least one section of the circumferential side of the light guide plate and that the back of the light guide plate is formed by a backlight-reflecting reflector layer.

Images