Front seat with an integrated projector for creating a floating real image for passengers in the rear of a vehicle

Abstract

The invention relates to a headrest or backrest, which is designed for installation in a vehicle seat and comprises an integrated privacy display for a passenger sitting behind it, comprising the following components: - an image generator arranged inside the headrest or backrest and designed to generate a light beam with the desired display content; - a cover disc or layer which is designed to allow the passage of the light beam and forms a surface portion of a rear side of the headrest or backrest; and - projection and imaging optics arranged in the beam path between the image generator and the cover disc or layer and designed in such a way that the light beam leaves the cover disc or layer directly in the direction of an eyebox intended for the eyes of this passenger and the display content is imaged onto a real image floating in the air between the cover disc or layer and the eyebox.

Description

[0001] Description

[0002] Front seat with an integrated projector to create a floating real image for passengers in the rear of a vehicle

[0003] The invention relates to a headrest or backrest designed for installation in a vehicle seat and comprising an integrated display for a passenger sitting behind it. The invention also relates to the vehicle seat and a vehicle equipped therewith. The vehicle can be a motor vehicle or another type of land, air, or water vehicle.

[0004] In motor vehicles or aircraft with rows of seats arranged one behind the other, direct-view displays in the form of flat screens are often installed in the backs of the front seats for passengers in the rear seats. Their display image is usually clearly visible from various directions and therefore has no or only a limited privacy function.

[0005] On the other hand, CN 217821128 U, for example, discloses the superimposition of a real image floating in the air into the field of vision of a driver and / or passenger of a vehicle when looking into the windshield. This involves using a concave imaging mirror, with the beam then leading via the reflection on the windshield to the eyeboxes of the driver and / or passenger, thus resulting in a so-called head-up display (HUD). However, it is not easy to display the superimposed image in the transparent area of ​​the windshield with sufficient brightness and high contrast, even in high ambient light.It is an object of the present invention to provide an alternative and / or improved display concept for passengers on rear seats of a vehicle, which enables an improvement over known display devices, for example with regard to the application possibilities, the installation space, the contrast, the visibility and / or other aspects.

[0006] This object is achieved by a headrest or backrest according to claim 1, as well as by a vehicle seat containing the same and a vehicle equipped therewith according to the independent claims. Further embodiments are specified in the dependent claims. All further features and effects mentioned in the claims and the following description for the headrest or backrest also apply to the vehicle seat and the vehicle, and vice versa.

[0007] According to a first aspect, a headrest or backrest is provided that is designed for installation in a vehicle seat. The vehicle can be a motor vehicle, but also any other land, air, or water vehicle, in particular an aircraft. Unless otherwise stated, all spatial orientation terms used herein, such as "above," "below," "side," "horizontal," "vertical," "in front," "behind," etc., refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical directions of the vehicle.

[0008] A privacy display is integrated into the headrest or backrest. It is designed to generate a display for a passenger sitting directly behind the specified seat in the vehicle (i.e., without any objects intervening that might interfere with the light propagation).

[0009] The privacy display has an imager arranged inside the headrest or backrest and configured to generate a light beam with the desired display content (also referred to herein as "projector light"). Furthermore, the privacy display includes a cover plate (also referred to as a cover glass) or cover layer configured to transmit the light beam, which forms a surface portion of a rear side of the headrest or backrest and thus faces directly toward the passenger during vehicle operation.

[0010] Furthermore, the privacy display comprises projection and imaging optics in the beam path between the imager and the cover plate or cover layer. These are arranged and designed such that the light beam leaves the cover plate or cover layer in a radiation direction that leads directly (i.e., without further deflection optics) to a spatial area (eyebox) predetermined for the eyes of the said passenger. The projection and imaging optics are designed to present the display content to this passenger as a real image floating freely in the air between their eyebox and the cover plate / cover layer. The passenger can see this image when their eyes are in the said eyebox and they look in the direction of the cover plate / cover layer. The floating image is real, i.e.It can be recorded by light-sensitive material and made visible to everyone by means of a light-scattering surface if such a material or surface were brought into its image position.

[0011] As is customary, the eyebox is understood to be the spatial area from which the displayed floating real image is fully visible. In other words, the light beam is essentially confined to this spatial area. Therefore, the generated image is only visible to the named passenger if their eyes are located within the predetermined eyebox, which, for example, does not extend beyond the width of their own vehicle seat. This allows confidential content to be presented to this passenger (“privacy”). On the other hand, other occupants, such as other passengers or flight attendants, are not visually disturbed by this display because they cannot see it. Furthermore, this spatial restriction of the light beam to the eyebox area also saves the light energy required to generate it.One idea of ​​the present invention therefore consists in the integration of a projector (privacy display) with a floating real image into a front seat of a vehicle for use by passengers in the rear of the vehicle. The integration of a display device for passengers in the rear area of ​​a vehicle can be difficult both in terms of installation space and in terms of freedom from reflections and visibility. These difficulties can be overcome by the design and arrangement of the privacy display in the headrest or backrest of a front seat proposed here, as explained in more detail below using a few examples. The proposed privacy display has an advantage over a head-up display, for example, in which the image of a bright external environment is superimposed, in that its cover plate / cover layer, with the interior of the headrest / backrest and the privacy display behind it, serves as the image background.This allows image brightness to be increased largely independently of ambient light levels, and contrast to be significantly improved. Unlike a conventional direct-view display, the privacy display's spatially limited eyebox protects the display content from prying eyes.

[0012] The aforementioned projection and imaging optics, particularly through a suitable selection of their effective focal length, allow the real image to be generated at a comfortable viewing distance from the passenger's eyes. For this privacy display, this viewing distance can be less than one meter or even less than half a meter. Such viewing distances can be optimal for reading or working, but are also very suitable for entertainment content such as games or videos.

[0013] In principle, any imaging technology is suitable for the imager. In particular, it can be designed to dynamically generate the required or desired display content in a two-dimensional pixel matrix. For example, the imager can be designed as a light-transmitting or light-emitting flat screen, such as a liquid crystal display (LCD) or a pLED or OLED display, or alternatively as a projector-based imager or a waveguide-based display. This makes it possible, for example, to generate display content that reproduces a work computer desktop or an open book and / or whose content can be controlled by the passenger concerned via a suitable user interface in the vehicle (such as acoustic input, touchpad, keyboard, and much more).

[0014] The cover plate / cover layer can be made of any material suitable for its functionality described herein, for example, plastic or glass. The cover plate / cover layer and in particular its user-facing surface can, for example, be planar (i.e., flat). However, the cover plate / cover layer can also have a freeform surface on one or both sides to create a predetermined optical effect. Last but not least, the cover plate / cover layer can also serve to mechanically protect the optical components of the privacy display, in particular the imaging optics and the image generator.

[0015] According to one embodiment, the projection and imaging optics comprise a concave mirror and / or a converging lens designed to project the display content generated in the imager onto the real image suspended in the air between the eyebox and the cover plate. To improve the imaging effect and / or further reduce installation space, the projection and imaging optics can, in particular, comprise two concave mirrors directly opposite one another in the beam path of the light beam and / or a lens system composed of multiple lenses. The respective imaging optical element can also be designed to have a beam-deflecting, image-magnifying, and / or image-correcting effect on the light beam. In addition, the projection and imaging optics can also comprise further deflecting elements, such as plane mirrors, for folding the beam path.According to a further development of this embodiment, the imager is designed to generate a linearly polarized light beam with a predetermined polarization direction, and the projection and imaging optics or the cover plate comprise a deflecting mirror arranged in the beam path between the imager and the concave mirror, and simultaneously between the concave mirror and the eyebox. The deflecting mirror is designed for essentially lossless reflection for the specified polarization direction and essentially lossless transmission for a polarization direction perpendicular thereto. "Essentially lossless reflection" can mean, for example, a reflection coefficient of more than 50%, in particular more than 60 or 70%, and ideally more than 80 or 90%.Similarly, "essentially lossless transmission" can mean, for example, a transmission coefficient of more than 50%, in particular more than 60 or 70%, and ideally more than 80 or 90%. The deflecting mirror can, for example, be arranged as a separate element in the beam path of the light beam between the first concave mirror and the cover plate, or it can be integrated into the cover plate or form the cover plate.

[0016] In addition, the projection and imaging optics include a polarization converter in the beam path between the deflecting mirror and the concave mirror, which the light beam passes through before and after its reflection by the concave mirror (i.e. twice in total), thereby rotating its polarization direction by 90°. This ensures that the light beam passes through the deflecting mirror largely unattenuated and unaffected after its reflection by the concave mirror and can therefore reach the eyebox. The deflecting mirror folds the beam path within the privacy display so that the path between the deflecting mirror and the concave mirror is used twice, which can result in a significant reduction in installation space. The polarization converter can, for example, be designed as a known A / 4 retarder in the form of a separate element (i.e. as an A / 4 plate) or in the form of a corresponding coating on the concave mirror.

[0017] For example, in this embodiment, the imager can be configured to generate the light beam with horizontal or s-polarization. After passing through the polarization converter twice, this linear polarization of the light beam is converted into vertical or p-polarization, allowing it to pass through the deflection mirror largely unhindered. In other words, in this example, the above polarization direction corresponds to horizontal or s-polarization, where the latter can be defined, for example, with reference to one of the reflection surfaces involved (i.e., the deflection mirror or one of the concave mirrors).

[0018] According to a further alternative embodiment, the projection and imaging optics comprise a microlens array or an arrangement of two or more microlens arrays arranged consecutively in the beam path. The microlens array(s) is / are designed to project the display content generated in the imager onto the real image suspended in the air between the eyebox and the cover plate or layer. Said cover layer can be formed on a user-facing surface of the last microlens array in the beam path. Alternatively, said cover plate can be provided separately from the microlens array or the arrangement of microlens arrays, which provides additional design freedom for both the last microlens array in the beam path and the cover plate itself.

[0019] The number of microlens arrays and their lens or surface geometries can be selected differently depending on the requirements of a specific application to enable different aperture angles and imaging properties (such as magnification, image distance, etc.). Compared to imaging optics based on imaging mirrors or lenses, microlens arrays require less installation space and enable, for example, a nearly sandwich-like construction of the entire privacy display with a correspondingly short beam path. This allows the privacy display to have a total thickness of less than 5 cm, for example, approximately 3 to 4 cm, approximately 3 to 3.5 cm, or even less, which further facilitates its integration into the headrest or backrest.

[0020] In order to make it significantly more difficult for the aforementioned passenger and other vehicle occupants to see inside the privacy display, or even to prevent it almost completely, the cover plate or layer can be designed to be at least partially opaque to ambient light entering from outside. To this end, it can comprise, for example, a perforated film, the addition of particles, coloring, tinting, a polarization filter and / or an LC layer that can be switched on uniformly (i.e. as a whole) or in segments. In particular, the cover plate or layer can have a higher transmittance for the outward-facing projector light than for the ambient light entering from outside, for example by means of layers / structures that block light on one side or suitable polarization filters, if necessary in combination with appropriately polarized projector light.

[0021] Due to this reduction in transparency, the cover panel / cover layer can be darkened to such an extent that it forms a dark or even black background for a particularly high-contrast display of the floating real image. Since the cover panel / cover layer, with the interior of the privacy display behind it, serves as the background image, darkening it can increase the image contrast.

[0022] In other words, the cover plate / cover layer can be deliberately darkened to serve as a contrast medium for displaying the floating real image with the desired contrast. Since the ambient light, unlike projector light, must pass through the cover plate / cover layer twice to illuminate the interior of the display for the occupants, it can be attenuated at least twice as much as the projector light by light-absorbing particles, perforation, or a suitable polarization filter in the cover plate / cover layer. For example, a perforated film with a transmittance of approximately 40% can ensure perfect visibility of the floating real image for the passenger, among other things because it transmits less than 16% of the disruptive ambient light, thus creating a dark image background.

[0023] The cover plate / cover layer can optionally additionally contribute to the shaping and / or directing of the light beam, for example through a specific prism shape, and thus form part of the projection and imaging optics. According to one embodiment, the cover plate can be designed in a prism shape to deflect the light beam upwards in order to vertically compress the installation space required for the privacy display and thereby output the light beam directly towards the eyebox. In particular, the prism-shaped cover plate / cover layer can have an at least approximately triangular shape in a vertical longitudinal section, tapering downwards. With this design, for example, integration of the privacy display into the backrest of the vehicle seat below its headrest is possible, where there may be more installation space.

[0024] According to one embodiment, the projection and imaging optics are designed to display the display content as a real image in an image plane or curved image surface suspended in the air between the cover plate / cover layer and the eyebox. By appropriately selecting the mutual arrangement and design of the image generator and the projection and imaging optics, an optimal orientation (in terms of image tilt) of the floating real image plane or surface for viewing the generated image can be achieved. This orientation is largely independent of the surface geometry of the headrest or backrest or the cover plate / cover layer and can therefore deviate significantly from it.In particular, this makes it possible to create a floating real image plane or image surface at positions and with orientations that are not available for hard display surfaces due to the arm and legroom required in the vehicle for the passenger in front of his or her vehicle seat.

[0025] According to a further aspect, the above vehicle seat is provided for a vehicle, in particular for a motor vehicle. Its headrest or backrest has, as described herein, an integrated privacy display.

[0026] According to a further aspect, the above-mentioned vehicle is provided. It comprises a first vehicle seat and a second vehicle seat arranged behind it in the vehicle's longitudinal direction. The privacy display is integrated into the headrest or backrest of the first vehicle seat and is configured to display a real image floating between the first and second vehicle seats for a passenger sitting on the second vehicle seat. The cover panel or layer of the privacy display faces the passenger in the second vehicle seat.

[0027] The cover panel / cover layer (or its user-facing surface) can, in particular, be inclined from the vertical to a vehicle floor at a predetermined first angle of inclination. In other words, it is then arranged obliquely with respect to the vertical direction of the vehicle, with its upper edge in the vehicle's longitudinal direction being closer to the passenger and the second vehicle seat than its lower edge.

[0028] This inclination of the cover panel / cover layer towards the ground ensures that all ambient light rays coming from the sun or artificial light sources inside and outside the vehicle and striking the cover panel / cover layer from above are always reflected towards the vehicle floor and therefore cannot enter the eyes of the passenger or other occupants as disruptive reflections. Furthermore, this oblique orientation of the opening aperture, away from the passenger and towards the ground, makes it more difficult for the passenger in question to gain an unwanted view into the interior of the privacy display. The aforementioned first angle of inclination can, for example, be at least approximately 10°, in particular at least approximately 20°, or even at least approximately 30° with respect to the vehicle's vertical direction.This inclination of the cover plate / cover layer can, for example, correspond to its tilting / rotation from a vertically aligned position around a horizontal axis which, when installed in the vehicle, corresponds to its transverse direction.

[0029] Alternatively or additionally, the above-mentioned floating real image plane / image surface can have a spatial orientation that differs significantly from the cover plate / cover layer, with a predetermined second angle of inclination from the vertical towards a roof liner (in other words upwards, and thus towards the eyebox). Due to this inclination, the floating real image plane / image surface is therefore inclined towards the user, which can be particularly ergonomic. Especially when reading, this can significantly reduce the variation in the image distance along the floating real image plane / image surface and the associated variation in the focus of the reader's eyes. The second angle of inclination, which is relative to the vertical (i.e.The angle of inclination (measured in the direction opposite to the first inclination angle (i.e., the vehicle height direction) can, for example, also be at least approximately 10°, in particular at least approximately 20°, or even at least approximately 30°. Thus, the floating real image plane / image surface and the user-side cover screen surface can be at an acute angle of at least approximately 10° or 20°, in particular at least approximately 30° or even at least approximately 60°, to one another in a vertical sectional plane spanned by the vehicle's longitudinal and height directions.

[0030] The above aspects of the invention and their embodiments and specific configurations are explained in more detail below using an example shown in the accompanying drawings. The drawings are to be understood as purely schematic illustrations of the basic optical design principle, i.e., not to scale. They show: Figure 1a shows a vertical longitudinal section through a vehicle seat with a privacy display integrated into its headrest according to an embodiment of the invention; and

[0031] Figure 1 b shows, in a vertical longitudinal section, an enlarged section of the vehicle seat of Fig. 1a, which shows a purely exemplary optical structure of the privacy display, as well as a floating real image generated by it and an associated eyebox.

[0032] All of the various embodiments, alternatives, and specific design features of the headrest or backrest, the vehicle seat, and the vehicle according to the above aspects of the invention mentioned above in the description and in the subsequent claims can be implemented in the example shown in Figures 1a-1b, in particular also alternatively or in addition to the features shown therein. Therefore, they will not all be repeated below. The same applies accordingly to the definitions and effects already given above with regard to individual features shown in Figures 1a-1b.

[0033] Fig. 1a shows a vertical longitudinal sectional view of a vehicle seat 1 with a headrest 4 and a privacy display 2 integrated therein according to an exemplary embodiment of the invention. The vehicle seat 1 is designed for installation in a vehicle 3, in this example a motor vehicle. The vehicle 3 is indicated in Fig. 1a only by the usual vehicle-fixed Cartesian coordinate system K with mutually perpendicular longitudinal, transverse, and vertical directions X, Y, and Z. As already mentioned, the spatial orientation terms such as "above," "below," "in front of," "behind," "horizontal," "vertical," etc., refer to this vehicle-fixed coordinate system K of the vehicle 3, unless explicitly stated otherwise. Fig. 1b shows a section A of the vehicle 3 or the vehicle seat 1, marked in Fig. 1a.This section A shows, in a highly simplified schematic vertical longitudinal section, a purely exemplary optical structure of the privacy display 2. The privacy display 2 is integrated inside the headrest 4 and contains an image generator 5 designed to generate a light beam L with the desired display content, a cover plate 6 designed to transmit the light beam L, and projection and imaging optics designed between them, which in this example comprises an imaging concave mirror 7 and a polarization-dependent reflecting or transmitting deflecting mirror 8. The light beam L (projector light) is only schematically indicated by its edge rays.

[0034] The image generator 5 is only schematically indicated in Fig. 1 and, in this example, has an image generation surface 5a in which a respective desired display content is generated as a real image. The image generator 5 can, purely by way of example, be designed as a flat screen, in particular a liquid crystal display (LCD), so that the display content is dynamically generated as a real image in its display surface, which forms the aforementioned image generation surface 5a. Alternatively, the image generator 5 can also be designed as a projector and, for example, contain a light-scattering projection surface onto which the respective display content is projected as a real image and which thus serves as the image generation surface 5a.Alternatively, the projector-based imager 5 can also comprise a laser scanner or a light source with suitable illumination optics for generating a homogeneous, collimated illumination beam and an image generation surface 5a illuminated thereby (for example in the form of an LCOS, Liquid Crystal on Silicon, or DMD, Digital Micromirror Device, not shown separately), which can be controlled pixel by pixel to generate the respective display content.

[0035] The user-side surface of the cover plate 6 forms a surface section 4a of a rear side of the headrest 4, which thus faces a passenger on another vehicle seat (not shown) arranged directly (i.e., without any intervening obstacles) behind the vehicle seat 1. In other words, the surface of the cover plate 6 is arranged directly opposite this passenger. The passenger is indicated in Fig. 1b only by a spatial area (eyebox E) predetermined for his or her eyes or head. The eyebox E is again sketched purely symbolically and, in this example, is limited to the area of ​​the aforementioned other vehicle seat (not shown).

[0036] The concave mirror 7 is designed to project the display content generated by the image generator 5 in the image generation surface 5a into a real image R floating freely in the air, which can be seen from the eyebox E when looking towards the cover plate 6. By appropriately selecting the mutual arrangement and design of the image generator 5 and the projection and imaging optics, an optimal position (in terms of image distance) and orientation (in terms of image inclination) of the floating real image R between the cover plate 6 and the eyebox E can be achieved, which would not be possible with conventional display technologies such as flat screens, etc. In particular, the passenger can view the floating real image R at a comfortable reading distance of, for example, approximately 30-50 cm from their eyes, without restricting their arm and legroom and without the image inclination depending on the geometry of the surface section 4a of the headrest 4.

[0037] To achieve a significant reduction in installation space, the privacy display 2 can optionally further comprise a deflecting mirror 8, which in Fig. 1 b forms a component of the projection and imaging optics. In this example, the light beam L generated by the image generator 5 with a predetermined linear polarization direction first strikes the deflecting mirror 8, which is designed for largely loss-free reflection for this polarization direction and reflects the light beam L to the concave mirror 7. In this example, the image generator 5 is designed to generate the light beam L with a horizontal or s-polarization, and the deflecting mirror 8 has a horizontally or s-reflecting coating 9, for example in the form of a correspondingly aligned wire grid polarizer.

[0038] In this example, the concave mirror 7 is equipped with a polarization converter 10 in the form of an λ / 4 coating, which the light beam L passes through twice upon reflection from the concave mirror 7, acting as an λ / 4 retarder each time. This rotates the polarization direction of the light beam L by 90°. The light beam L, now vertically or p-polarized, then strikes the deflecting mirror 8 again and is transmitted largely loss-free this time through its horizontally or s-reflecting coating 9. The light beam L then strikes the cover plate 6, from which it is also transmitted largely loss-free, thus reaching the eyebox E directly.

[0039] List of reference symbols

[0040] 1 vehicle seat

[0041] 2 Privacy Display

[0042] 3 vehicles

[0043] 4 headrest

[0044] 4a Surface section of a back of the headrest

[0045] 5 imagers

[0046] 5a Image generation area

[0047] 6 Cover plate

[0048] 7 imaging concave mirror

[0049] 8 deflecting mirrors

[0050] 9 horizontal or s-reflective coating

[0051] 10 polarization converters

[0052] L Light beam, also called projector light

[0053] R real image floating in the air

[0054] E Eyebox

[0055] K vehicle-fixed coordinate system

[0056] X, Y, Z longitudinal, transverse and height directions of the vehicle

Claims

Claims 1. A headrest (4) or backrest designed for installation in a vehicle seat (1) and comprising an integrated privacy display (2) for a passenger sitting behind it, with the following components: an image generator (5) arranged inside the headrest (4) or backrest and designed to generate a light beam (L) with the desired display content; a cover plate or layer (6) designed to transmit the light beam (L), which forms a surface section (4a) of a rear side of the headrest (4) or backrest;and a projection and imaging optics arranged in the beam path between the image generator (5) and the cover plate or layer (6) and designed in such a way that the light beam (L) leaves the cover plate or layer (6) directly in the direction of an eyebox (E) predetermined for the eyes of this passenger and the display content is projected onto a real image (R) floating in the air between the cover plate or layer (6) and the eyebox (E); 2. Headrest (4) or backrest according to claim 1, wherein the projection and imaging optics comprise a concave mirror (7) and / or a converging lens, which is / are used to project the display content generated in the image generator (5) onto the screen arranged between the eyebox (E) and the cover plate (6) are formed to form a real image (R) floating in the air.

3. Headrest (4) or backrest according to claim 2, wherein the imager (5) is designed to generate a linearly polarized light beam (L) with a predetermined polarization direction; the projection and imaging optics or the cover plate (6) comprise a deflecting mirror (8) which is arranged in the beam path between the imager (5) and the concave mirror (7) and simultaneously also between the concave mirror (7) and the eyebox (E) and is designed for essentially loss-free reflection for the said polarization direction and for essentially loss-free transmission for a polarization direction perpendicular thereto; and the projection and imaging optics in the beam path between the deflecting mirror (8) and the concave mirror (7) comprise a polarization converter (10) designed such that the light beam (L) passes through it a total of twice, thereby rotating its polarization direction by 90°.

4. Headrest (4) or backrest according to claim 3, wherein the deflecting mirror (8) is formed as a separate element in the beam path of the light beam (L) between the concave mirror (7) and the cover plate (6); or is integrated in the cover plate (6) or forms it.

5. Headrest (4) or backrest according to claim 1, wherein the projection and imaging optics comprise a microlens array or an arrangement of two or more microlens arrays following one another in the beam path; the microlens array(s) is / are designed to project the display content generated in the image generator (5) onto the real image (R) suspended in the air between the eyebox (E) and the cover plate or layer (6); and either the cover layer is formed on a user-side surface of the last microlens array in the beam path or the cover plate is arranged separately from the microlens array or the arrangement of microlens arrays.

6. Headrest (4) or backrest according to one of the preceding claims, wherein the cover plate or layer (6) is opaque to ambient light incident from outside by a perforated film, particle addition, coloring, tinting, a polarization filter and / or a segmentally or uniformly switchable LC layer to such an extent that it essentially prevents vehicle occupants from seeing into the interior of the privacy display (2).

7. Headrest (4) or backrest according to one of the preceding claims, wherein the cover plate or layer (6) is prism-shaped for deflecting the light beam (L) upwards in order to vertically compress the installation space required for the privacy display (2) and thereby output the light beam (L) directly in the direction of the eyebox (E); and the prism-shaped cover plate or layer (6) in a vertical longitudinal section preferably has at least has an approximately triangular shape, tapering towards the bottom.

8. Headrest (4) or backrest according to one of the preceding claims, wherein the projection and imaging optics are designed to represent the display content as a real image (R) in a real image plane or surface suspended in the air between the cover plate or layer (6) and the eyebox (E); and this suspended real image plane or surface has a spatial orientation that differs significantly from the surface section (4a) and is optimized for the ergonomics of the passenger when viewing the real image (R).

9. Vehicle seat (1), in particular for a motor vehicle (3), comprising: a headrest (4) or backrest according to one of the preceding claims.

10. Vehicle (3), in particular a motor vehicle, with mutually perpendicular longitudinal, transverse and vertical directions (X, Y, Z) of a vehicle-fixed Cartesian coordinate system (K), comprising: a first vehicle seat (1) according to claim 9 and a second vehicle seat arranged behind it in the vehicle longitudinal direction (X); wherein the privacy display (2), which is integrated in the headrest (4) or backrest of the first vehicle seat (1), is designed to display a real image (R) floating between the first and second vehicle seats for a passenger on the second vehicle seat; and the cover plate or layer (6) of the privacy display (2) faces the passenger on the second vehicle seat and preferably at a predetermined angle of inclination is inclined from the vertical towards the floor of the vehicle.

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