Display device in a vehicle

Abstract

Display device in a vehicle, comprising a holographic film (2; 2a, 2b, 2c, 2d); and a projector (4; 4a, 4b) arranged such that it emits at least some light in the direction of the holographic film (2; 2a, 2b, 2c, 2d); wherein the holographic film (2; 2a, 2b, 2c, 2d) is arranged on a disc (8, 9) of the vehicle; and wherein a black printing layer (6) is provided which is located on a side of the holographic film (2; 2a, 2b, 2c, 2d) opposite the projector (4; 4a, 4b) is arranged and overlaps an overlap area (10; 10a) of the holographic film (2; 2a, 2b, 2c, 2d), wherein the overlap area (10; 10a) is at least partially illuminated by the projector (4; 4a, 4b); wherein the holographic film (2; 2a, 2b, 2c, 2d) has at least one diffracting structure which diffractes light of a color corresponding to the diffracting structure coming from the projector (4; 4a, 4b) in the direction of a predetermined field of view (24; 26, 28) in the passenger compartment of the vehicle; wherein a diffracting structure for red light, a diffracting structure for green light and a diffracting structure for blue light are provided.

Description

[0001] The present invention relates to a display device in a vehicle. Background of the invention

[0002] Optical display systems in motor vehicles, with their mirrors, screens, and other optical components, require a great deal of space in the instrument panel. Holographic films, or so-called holographic-optical elements, offer a space-saving alternative for creating optical functions.

[0003] DE 10 2019 215 354 A1 relates to a method for controlling the transparency of a display surface for a projection device. WO 2018 / 206 314 A1 relates to a HUD system (head-up display system) and a method for generating HUD images.

[0004] DE 10 2016 225 994 A1 relates to a projection device for a motor vehicle and a method for displaying a virtual image to a driver of a motor vehicle. DE 10 2019 119 367 A1 relates to a laminated glass windshield for a motor vehicle. Disclosure of the invention

[0005] According to the invention, a display device in a vehicle is proposed, comprising the features of claim 1. Advantageous embodiments are the subject of the dependent claims and the following description.

[0006] The invention utilizes the measure of providing a black print layer on the side of a holographic film facing away from the optical projector. The holograms are thus (spatially) positioned in front of the black print, resulting in high contrast and thus good readability of projected images (such as a speedometer). Information / images can be displayed significantly closer to the normal field of vision of vehicle occupants, especially the driver, than with conventional dashboard-mounted displays.

[0007] Specifically, the display device comprises a holographic film and a projector positioned to emit light, at least partially, towards the holographic film. The holographic film is mounted on a window of the vehicle or integrated as an intermediate layer within a laminated glass pane. A black print layer is provided on the side of the holographic film opposite the projector, optionally also integrated into the laminated glass pane. The black print layer overlaps the holographic film in a partial area, referred to as the overlap area, which is at least partially illuminated by the projector.

[0008] Holographic films are primarily thin, transparent films made of a photosensitive polymer (photopolymer) into which an optical function based on refractive index modulation can be introduced using an exposure process. Depending on the exposure, holographic films manipulate the light, allowing them to direct and diffract directional light rays, similar to how mirrors or lenses work with real, optically active objects.

[0009] Holographic films can have a single- or multi-layer structure, with at least one holographic layer (for example, with a thickness in the range of 15 µm to 100 µm) into which holographic structures or a hologram are embedded. A photopolymer is used for the holographic layer; that is, a material that changes its properties when irradiated in its uncured state with light in a specific frequency range (usually UV or visible light), causing the polymers to cross-link. These changes are then fixed by curing, allowing optical elements such as holographic structures (diffraction gratings) to be created. A further layer, for example, a support layer (with a thickness in the range of 50 µm to 300 µm), can also be included.The substrate layer can be made of materials such as polyamide, polycarbonate, and / or cycloolefinic copolymers. The holographic layer and, if applicable, the at least one substrate layer are transparent, except for the optical properties of the holographic structures.

[0010] A hologram is understood to be, in particular, a holographic-optical element, i.e., a holographic structure within a photopolymer layer that functions like a conventional optical element, such as a lens, diffraction surface, or mirror. Such a holographic-optical element is formed, for example, by a holographic grating, i.e., a diffraction grating with a low grating constant, where the diffraction grating is formed, for instance, by a corresponding variation in the refractive index within the photopolymer layer. This structuring within the photopolymer layer is hereinafter referred to as a holographic structure.

[0011] The term "black ink layer" refers to an opaque layer of black ink. The black ink layer can be completely opaque or partially transparent. In a partially transparent version, the black ink layer darkens the image visible through it. The transparency of the black ink layer, particularly for light in the visible wavelength range, can be, for example, between 0% and 90%, preferably between 0% and 50%, more preferably between 0% and 25%, and most preferably between 0% and 10%.

[0012] The term "projector" generally refers to an optical projection unit or system designed to project images in the form of light in at least one specific direction, i.e., within a certain angular range or projection area in that direction. LEDs (light-emitting diodes) are preferably used as the light source in projectors because they can be made relatively small.

[0013] Furthermore, the holographic film includes a transparent area located within the lens that is not overlapped by the black printed layer. This overlapping area is preferably positioned between the edge of the lens and the transparent area. This allows for an increase in the area usable for holographic projections, with the transparent area extending into the normal field of vision of a vehicle occupant looking at the road, since the holographic film itself is transparent. Holographically projected information / images are thus superimposed on the vehicle occupant's field of vision, similar to a HUD (Head-up Display).

[0014] Preferably, the overlapping area has a first diffracting structure and the transparent area a second diffracting structure; wherein the first diffracting structure is configured to diffract light from the projector towards a first field of view and the second diffracting structure is configured to diffract light from the projector towards a second field of view; wherein preferably the first field of view is different from the second field of view. Images intended for different vehicle occupants can thus be diffracted or scattered into corresponding fields of view.

[0015] Preferably, the second field of vision is included within the first field of vision; wherein preferably the first field of vision comprises a driver's eye area and a passenger's eye area, and the second field of vision comprises the driver's eye area. The terms "driver's eye area" and "passenger's eye area" are intended here to refer to the areas inside the vehicle where the eyes of the driver and the passenger are typically located, respectively. These areas can be chosen to be sufficiently large so that the eye areas of people of different heights and seating positions are covered. The first field of vision can be used to display information of interest to both the driver and the passenger (e.g., weather information, the time, a song playing from the vehicle's sound system, or similar). The second field of vision can be used to display information of interest only to the driver (e.g.,Speed ​​information, warnings, or similar). The passenger's eye area is preferably not included in the second field of vision.

[0016] According to the invention, the holographic film has at least one diffraction structure that diffracts light from the projector, of a wavelength or color corresponding to the diffraction structure, towards a predetermined field of view in the passenger compartment of the vehicle; wherein one diffraction structure is provided for red light, one for green light, and one for blue light. By designing the diffraction structures specifically for certain colors of light (i.e., for specific spectral colors), high contrast can be ensured. By using red, green, and blue, all colors visible to humans can be displayed. Red light can have a wavelength range of 630 to 700 nm (nanometers), green light can have a wavelength range of 490 to 560 nm, and blue light can have a wavelength range of 450 to 490 nm.

[0017] Preferably, the holographic film has several diffraction structures configured to diffract light in the direction of the same field of vision or in the direction of different fields of vision in the passenger compartment of the vehicle. The diffraction structures can be used to diffract images in specific, in particular different, directions, or to diffract different colors of an image in a specific, in particular the same, direction.

[0018] Preferably, the holographic film and / or the black print layer are integrated into the glass; the glass is preferably a laminated glass pane, and the holographic film and / or the black print layer are integrated into the laminated glass layers. This allows for easy installation, as the holographic film or the black print layer can be pre-mounted in the glass, and then the glass is installed on the vehicle.

[0019] Preferably, the holographic film and the black ink layer are also arranged in an area outside the disc that extends to the disc. Areas directly adjacent to the disc can thus be used as a projection surface. Preferably, the projector is configured to illuminate an area that at least partially encompasses the holographic film both inside and outside the disc. This configuration allows for the creation of a relatively large display area compared to, for example, a single holographic film inside the disc.

[0020] Preferably, the projector is mounted on or under the vehicle's dashboard, on the vehicle's ceiling, and / or on a pillar bordering the windshield. For the sake of simplicity, this application always refers to a single projector. However, multiple projectors illuminating the same or different holographic films are also possible. That is, "a projector" should be understood as "at least one projector." In principle, these multiple projectors can also be considered sub-projectors of a single projector or projector system.

[0021] Preferably, the pane is a windshield or, in particular, a front side window (i.e., a pane of a front side window) of the vehicle. These are typically within the field of vision of vehicle occupants. It is also conceivable that the pane is a pane of a rear side window or a rear window of the vehicle.

[0022] The black ink layer is preferably positioned at an edge of the vehicle's windshield and / or outside the driver's field of vision, so that it does not, or only very minimally, impair the normal field of vision. The driver's field of vision lies in a vertical strip approximately 30 cm wide, precisely in the center of the steering wheel. The area covered by the windshield wipers is the upper and lower boundary of the driver's field of vision.

[0023] Preferably, the black printed layer has an extent of less than 10 cm, measured perpendicular to the edge of the pane, and more preferably less than 5 cm. The view through the pane is thus relatively unaffected. A possible minimum extent is, for example, 2 cm or 1 cm.

[0024] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0025] The invention is schematically illustrated in the drawing using exemplary embodiments and is described below with reference to the drawing. Brief description of the drawings Fig. Figure 1 shows a sectional view of the arrangement of a display device in a vehicle. Fig. Figure 2 shows a sectional view of the arrangement of a display device according to the invention in a vehicle according to a preferred embodiment. Fig. Figure 3 shows a possible embodiment of the present invention in a perspective view. embodiment(s) of the invention

[0026] Fig. Figure 1 shows a sectional side view of the arrangement of a display device in a vehicle. The display device comprises a holographic film 2, a projector 4, and a black printing layer 6.

[0027] The holographic film 2 is arranged in the windshield 8 (e.g., between layers of a laminated glass windshield). The holographic film 2 is positioned at the lower edge of the windshield (the root of the glass). A holographic structure (e.g., an optical grating in the form of refractive index variations) or a hologram is enclosed within the holographic film 2.

[0028] The projector 4 is arranged below the dashboard 20 and oriented such that the light 14 emitted by the projector 4 falls at least partially onto the holographic film 2, i.e., the projector illuminates the holographic film. For example, the projector 4 can be arranged in or together with a recess 22 in the dashboard 20, as shown. The holographic structure in the holographic film 2 diffractes (scatters) or reflects the light from the projector and directs it as diffracted light 16 towards a field of view 24. The holographic film, in particular the holographic structure (e.g., line spacing of the structure), the projector (in particular the wavelength of the emitted light), and their relative positioning are thus arranged or coordinated such that the emitted light is diffracted towards the field of view 24.

[0029] The black print layer 6 is located on the side of the holographic film 2 facing the projector 4; from the projector's perspective, the black print layer 6 is therefore behind the holographic film 2. The black print layer 6 overlaps the holographic film 2 in an overlap area 10 of the holographic film. This overlap area can cover the entire black print layer 6.

[0030] The arrangement is designed such that the light 14 emitted by the projector 4 falls at least partially on the overlap area 10.

[0031] The black print layer can also be arranged between layers of the laminated glass windshield 8, e.g. directly next to the holographic film 2, whereby it is also possible that the black print layer is applied to the holographic film 2, thus facilitating assembly on the windshield.

[0032] The black printing layer 6 extends only along one edge of the windscreen 8, and thus has an extent such that it does not extend into the normal field of vision of a vehicle occupant looking at the road (for example, the black printing layer is only located in an area where the hood would be visible from the perspective of the vehicle occupant).

[0033] Fig. Figure 2 shows a lateral sectional view of the arrangement of a display device according to the invention in a vehicle according to a preferred embodiment. The design largely corresponds to the design of the Fig. 1, so that for common features the description Fig. 1 is referenced and the differences are explained below.

[0034] Unlike Fig. 1. The black print layer 6 does not overlap the entire holographic film 2; instead, the holographic film 2 has a transparency area 12 located next to the overlap area 10, specifically towards the center of the disc 8. The overlap area is therefore situated between the edge of the disc and the transparency area. Unlike the overlap area 10, the transparency area 12 can extend into the normal field of vision of vehicle occupants because the holographic film 2 itself is transparent.

[0035] Projector 4 is set up here so that the light emitted from it falls on both the overlap area 10 and the transparency area 12.

[0036] The holographic film 2 exhibits transparency area 12 as well as overlap area 10, cf. Fig. 1, a (second) holographic structure is created that diffractes light coming from the projector towards the vehicle interior. The (second) holographic structure in the transparency area 12 can be designed such that light 32 diffracted by it is diffracted towards a second field of view 28. The (first) holographic structure in the overlap area 10 is designed, by way of example, such that light 30 diffracted by it is diffracted towards a first field of view 26.

[0037] The second field of view 28 is shown in the figure as an example enclosed within the first field of view 26. Partial overlap of the fields of view or a design such that the fields of view are disjoint is also conceivable. The first field of view 26 covers, as an example, the driver's field of view of a vehicle driver 34 (here, for example, information primarily relevant to the driver can be displayed, such as information concerning the driving or road situation, warnings, or similar). The second field of view 28 covers, as an example, both the driver's field of view and the passenger's field of view of a passenger 36 (here, for example, images of interest to all vehicle occupants can be displayed). "Fields of view" here refers to areas inside the vehicle, i.e.,in the passenger compartment, in which, assuming a typical seating position, the eyes of the respective vehicle occupant are located, whereby the eye areas can be defined as sufficiently large so that different sized vehicle occupants and different seating positions are covered.

[0038] Of course, it is also possible that several holographic structures are provided in the overlap area and / or in the transparency area itself, which bend light towards different fields of view; this can also happen depending on a spectral color.

[0039] In addition to or deviating from the arrangement of the holographic foil 2 and the black print layer 6 within the disk surface, it is also possible to arrange them outside the disk, next to the edge of the disk. This is shown in the following. Fig. 3 illustrated.

[0040] Fig. Figure 3 shows a perspective view of a possible embodiment of the present invention. This figure illustrates, in particular, different possible mounting positions for holographic films, black printing layers, and projectors. Beyond this, reference is made to the description of the Fig. 1 and Fig. 2 referred.

[0041] The illustrated configuration features several holographic sheets 2a, 2b, 2c, 2d, each of which can be present independently of one another. A first holographic sheet 2a, arranged in the windshield 8, has an overlap area 10a, in which the holographic sheet is overlapped by a black print layer (not shown in detail) (viewed from the perspective of the figure, the black print layer is located behind the holographic sheet), and a transparency area 12a (i.e., without a black print layer). This corresponds to the arrangement in Fig. 2. Unlike in Fig. 2. The holographic film 2a is not illuminated by a projector located in the dashboard, but by two projectors 4a arranged on the ceiling of the passenger compartment. In general, several projectors can be provided, adapted to the size of the holographic film, to achieve uniform illumination.

[0042] Furthermore, a second holographic film 2b is provided on the dashboard 22, directly adjacent to the windshield 8 and thus directly adjacent to the first holographic film 2a. A black printed layer can again be provided here (behind the holographic film when viewed from the figure's perspective; not shown in detail). This layer can be omitted if the section of the dashboard containing the second holographic film 2b is a suitable color. The second holographic film 2b is also illuminated by the projectors 4a mounted on the ceiling. The first holographic film 2a and the second holographic film 2b can together form a single projection surface.

[0043] Additionally, a third holographic film 2c (in the left side window) and a fourth holographic film 2d are provided in the side windows 9 of the vehicle. These are illuminated by projectors 4b mounted on the A-pillars. The projectors could also be mounted on the ceiling or on the sides of seats; the latter is advantageous because any movement of the respective seat is automatically compensated for. Besides an overlapping area, the third and fourth holographic films 2c, 2d can optionally also have a transparency area (similar to the Fig. 2 or the first holographic film 2a; not shown). Similarly, holographic films could be provided on the side doors directly below the side window, forming common projection surfaces with the third or fourth holographic film.

[0044] It should also be noted that holographic films can serve as a projection surface for any information, images, videos, and so on. In particular, they can also serve as a display for recordings from an external camera of the vehicle.

Claims

[1] Display device in a vehicle, comprising a holographic film (2; 2a, 2b, 2c, 2d); and a projector (4; 4a, 4b) arranged such that it emits at least some light in the direction of the holographic film (2; 2a, 2b, 2c, 2d); wherein the holographic film (2; 2a, 2b, 2c, 2d) is arranged on a disc (8, 9) of the vehicle; and wherein a black printing layer (6) is provided which is located on a side of the holographic film (2; 2a, 2b, 2c, 2d) opposite the projector (4; 4a, 4b) is arranged and overlaps an overlap area (10; 10a) of the holographic film (2; 2a, 2b, 2c, 2d), wherein the overlap area (10; 10a) is at least partially illuminated by the projector (4; 4a, 4b); wherein the holographic film (2; 2a, 2b, 2c, 2d) has at least one diffracting structure which diffractes light of a color corresponding to the diffracting structure coming from the projector (4; 4a, 4b) in the direction of a predetermined field of view (24; 26, 28) in the passenger compartment of the vehicle; wherein a diffracting structure for red light, a diffracting structure for green light and a diffracting structure for blue light are provided. [2] Display device according to claim 1, wherein the holographic film (2; 2a, 2b, 2c, 2d) comprises a transparency area (12) located within the disk (8) which is not overlapped by the black printing layer (6). [3] Display device according to claim 2, wherein the overlap area (10; 10a) has a first diffracting structure and the transparency area (12; 12a) has a second diffracting structure; wherein the first diffracting structure is configured to diffract light from the projector towards a first viewing area (26), and the second diffracting structure is configured to diffract light from the projector towards a second viewing area (28); wherein preferably the first viewing area (26) is different from the second viewing area (28). [4] Display device according to claim 3, wherein the second field of view (28) is included in the first field of view (26); wherein preferably the first field of view (26) includes a driver's eye area and a passenger's eye area and the second field of view (28) includes the driver's eye area. [5] Display device according to one of the preceding claims, wherein the holographic film (2; 2a, 2b, 2c, 2d) has several diffracting structures configured to diffract light in the direction of the same field of view (24; 26, 28) or in the direction of different fields of view (24; 26, 28) in the passenger compartment of the vehicle. [6] Display device according to one of the preceding claims, wherein the holographic film (2, 2a) and / or the black print layer (6) are integrated into the disc (8, 9); wherein the disc (8, 9) is preferably a laminated glass disc and the holographic film (2; 2a, 2b, 2c, 2d) and / or the black print layer (6) are integrated into the layer composite of the laminated glass disc. [7] Display device according to one of the preceding claims, wherein the holographic film (2b) and optionally also the black printing layer (6) are arranged in an area outside the disk (8, 9) which extends to the disk. [8] Display device according to claim 7, wherein the projector (4a) is configured to illuminate an area which at least partially encompasses the holographic film (2a, 2b) inside and outside the disk (8, 9). [9] Display device according to one of the preceding claims, wherein the projector (4; 4a, 4b) is arranged on and / or under a dashboard of the vehicle, on a ceiling of the vehicle or on a column that delimits the screen (8, 9). [10] Display device according to one of the preceding claims, wherein the disc (8, 9) is a windscreen (8) or a side window (9) of the vehicle. [11] Display device according to one of the preceding claims, wherein the black printing layer (6) has an extent measured perpendicular to an edge of the disk (8, 9) of less than 10 cm, preferably less than 5 cm. [12] Display device according to one of the preceding claims, wherein the black printing layer (6) is arranged outside a driver's field of vision.

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