Compact privacy display in an instrument panel of a vehicle, having a freeform prism as cover pane

Abstract

The invention relates to a compact privacy display for installation in an instrument panel of a vehicle. The privacy display comprises an imager designed to generate a light beam comprising desired display content and a cover pane that is transparent to the light beam and is intended for arrangement in a surface section of the instrument panel that faces a vehicle occupant on a front vehicle seat. It also comprises a projection and / or imaging optical unit that is arranged between the imager and the cover pane in the beam path and is designed to display the display content as a real image or virtual image that hovers in the air in front of or behind the cover pane. The cover pane is designed to deflect the light beam upwards in a prism shape in order to vertically reduce an installation space required for the privacy display and to output the light beam directly in the direction of a region of space intended for the eyes of said occupant.

Description

[0001] Description

[0002] Compact privacy display in a vehicle instrument panel, with a freeform prism as cover glass

[0003] The invention relates to a privacy display for installation in a vehicle's instrument panel for generating a real image or a virtual image floating in the air for a vehicle occupant. The invention also relates to a vehicle equipped therewith.

[0004] So-called head-up displays (HUDs) are known for vehicles; these are used to project an image into the field of vision of an occupant via reflection from a partially transparent reflective screen, typically a windshield or a combiner screen provided specifically for this purpose. This allows, for example, speed information and other useful navigation, warning and vehicle operating information to be superimposed in the form of a virtual image on the real surroundings in front of the vehicle as observed by the driver or another occupant. For this purpose, a classic HUD for the driver, for example, comprises a projection unit housed in the instrument panel which generates a bundle of light rays with the desired display content and projects it in a suitable shape and direction onto the windshield of the vehicle or onto a combiner screen arranged in front of it on the inside of the vehicle, from where it is projected to the eyes of the driver or another occupant.to a predetermined spatial area (eyebox).

[0005] To read a head-up display, the driver doesn't need to take their eyes off the road and, with a suitable projection lens design, doesn't need to significantly refocus. However, it's not easy to display the HUD image in the transparent area of ​​the windshield with sufficient brightness and high contrast, even in high ambient light.

[0006] In the prior art, head-up displays are also proposed as passenger entertainment or as driver entertainment during parking or autonomous driving. In addition to virtual image display, CN 217821128 U, for example, discloses the generation of a real image suspended in the air for one or more viewers using an imaging concave mirror. In vehicle applications, the beam path leads to the eyeboxes of a driver and a passenger via reflection from the windshield.

[0007] It is an object of the present invention to provide an alternative and / or improved display device for a vehicle which enables an improvement over known devices, for example with regard to installation space, contrast, visibility, image quality and / or other aspects.

[0008] This object is achieved by a privacy display according to claim 1 and by a vehicle equipped therewith according to the independent claim. Further embodiments are specified in the dependent claims. All further features and effects mentioned in the claims and the following description for the privacy display also apply to the vehicle, and vice versa.

[0009] According to a first aspect, a compact privacy display is provided that is designed for installation in an instrument panel of a vehicle. The vehicle can be a motor vehicle, but also any other land, air, or water vehicle.

[0010] The privacy display comprises an imager designed to generate a light beam with the desired display content (also referred to herein as projector light), as well as a cover plate designed to transmit the light beam. In principle, any imaging technology is suitable for the imager, in particular a light-transmitting or light-emitting flat screen, a projector-based imager, or a waveguide-based display. The cover plate is designed for placement in a surface section of the instrument panel facing a vehicle occupant in a front vehicle seat, so that the cover plate, when mounted, is positioned with its surface directly opposite the occupant.Furthermore, the privacy display comprises a projection and / or imaging optic arranged in the beam path between the image generator and the cover plate, which is designed to display the display content as a real image floating freely in the air in front of the cover plate (i.e. in the passenger compartment) from the occupant's perspective, or as a virtual image floating beyond the cover plate (i.e. inside the instrument panel or even further away).

[0011] The cover panel is designed in such a prism-shaped manner that it deflects the light beam upwards, thereby vertically compressing the overall installation space required for the privacy display. The light beam exits the cover panel in a direction of radiation that leads directly (i.e., without additional deflection surfaces) to a spatial area (eyebox) predetermined for the eyes of the occupant. Consequently, the occupant can see the generated image when looking toward the cover panel.

[0012] As is customary, an eyebox is defined as a spatial area from which the displayed real or virtual 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 those occupants whose eyes are located within the designated eyebox, which, for example, does not extend beyond the width of their vehicle seat. This allows confidential content to be displayed to these occupants (“privacy”). On the other hand, other occupants, such as the driver, are not visually disturbed by this display because they cannot see it.

[0013] One idea of ​​the present invention is the implementation of a (freeform) prism as a cover plate in the instrument panel to optimize installation space and improve the optics when integrating the projector (privacy display) described herein into the instrument panel. Integrating such a projector into the instrument panel can otherwise lead to installation space problems, since the eyebox position and thus the required beam direction are predetermined by the vehicle geometry, while the available installation space in the instrument panel and its shape are also predetermined or severely limited.To resolve this installation space conflict and simultaneously gain more freedom in the design of the imaging and projection optics, the cover glass of the privacy display presented here is designed as a prism, specifically a freeform prism, which can follow the specified shape of the instrument panel while simultaneously deflecting the light beam. This allows the installation space required for the imager and the imaging and projection optics to be redirected or compressed accordingly, thus adapting it to the specified installation space geometry in the instrument panel.

[0014] Furthermore, the privacy display presented here has the advantage over a head-up display, in which the image is superimposed on a bright exterior of the vehicle, in that the cover screen, with the interior of the instrument panel and the privacy display behind it, serves as the image background. This allows the image brightness to be increased largely independently of the ambient brightness and also significantly improves the contrast.

[0015] According to one embodiment, the prism-shaped cover plate is designed as a freeform prism with a freeform surface facing the occupant and / or the projection and / or imaging optics, which is designed to adapt to a predetermined surface geometry of the instrument panel and / or to provide an additional image-correcting and / or imaging effect. Alternatively or additionally, the prism can have an at least approximately triangular shape in a vertical longitudinal section (taken in the beam propagation direction), which can taper downwards, for example, to achieve the aforementioned upward deflection.

[0016] In a specific embodiment, the cover panel can include particle addition, coloring, tinting, or a polarization filter, thereby darkening it to such an extent that direct visibility into the interior of the privacy display is largely prevented for vehicle occupants. At the same time, a contrast medium is created for displaying the real or virtual image with a desired contrast. Since the cover panel, with the interior of the instrument panel and the privacy display behind it, serves as the image background, darkening it can increase the image contrast.And since, unlike the head-up display mentioned above, the image is not projected against the bright exterior of the vehicle, a significantly better contrast result can be achieved with a significantly lower intensity of the projector light than with a HUD, so that despite a certain attenuation of the projector light by the darkened cover screen, a higher contrast can be achieved.

[0017] Since the ambient light, unlike the projector light, has to pass through the cover plate twice to illuminate the interior of the privacy display for the occupants, it can be attenuated by light-absorbing particles or a suitable polarization filter in the cover plate to at least twice the extent as the projector light.

[0018] The polarization filter can be designed, in particular, as a circular polarizer, consisting of an λ / 4 retarder facing the projection and / or imaging optics and a linear polarizer (also called a linear polarizer) facing the occupant. Thus, the unpolarized ambient light striking the cover screen from outside is first attenuated by half by the linear polarizer and then circularly polarized in the appropriately aligned λ / 4 retarder. If this ambient light is reflected back to the cover screen inside the privacy display, it again has a linear polarization after the second pass through the λ / 4 retarder, but with a polarization direction rotated by 90° relative to the transmission direction of the linear polarizer. Thus, the reflected ambient light is blocked or absorbed by the linear polarizer—in other words, completely extinguished.

[0019] Ideally, the imager in this configuration is designed to generate the light beam with such circular polarization that, after passing through the λ / 4 retarder, it has a linear polarization that is transmitted by the linear polarizer and can therefore pass through the polarization filter largely unattenuated. Alternatively, the projector light can also have a polarization that is not manipulated by the λ / 4 retarder. In this case, the projector light is linearly polarized parallel to the fast or slow axis of the λ / 4 retarder and is therefore also transmitted by the linear polarizer at 50%.

[0020] Alternatively, any other polarization filter can be used, such as a linear polarizer, which allows projector light polarized in its transmission direction to pass through unattenuated, but blocks at least half of the unpolarized ambient light.

[0021] According to one embodiment, the projection and / or imaging optics comprise at least one concave mirror, which can be designed, for example, to deflect, magnify, and / or correct the beam. Alternatively or additionally, the projection and / or imaging optics can also comprise, for example, plane mirrors and other deflecting elements for folding the beam path and / or lenses and other imaging elements for generating the real image or for determining the display properties of the virtual image. In particular, the projection and / or imaging optics can comprise two concave mirrors directly opposite one another in the beam path of the light beam. This can be expedient for a particularly compact beam path and / or for particularly good imaging properties, especially for generating the real image.

[0022] According to a further aspect, the above-mentioned vehicle is provided. The spatial orientation terms used herein, such as "top," "bottom," "lateral," "horizontal," "vertical," etc., refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical axes of the vehicle.

[0023] The vehicle comprises a windshield, an instrument panel extending therebelow, and at least one front vehicle seat arranged opposite the instrument panel. It is equipped with at least one privacy display of the type presented herein. Each of these privacy displays is integrated into the instrument panel such that its cover forms a surface section of the instrument panel facing a vehicle occupant in one of the front vehicle seats.

[0024] According to one embodiment, the cover plate is arranged in the instrument panel such that its user-facing surface is flush with adjacent surface sections of the instrument panel. In other words, in this embodiment, the user-facing surface of the cover plate follows the surface shape of the instrument panel or forms a continuation of it.

[0025] In particular, one of the privacy displays can be arranged opposite a passenger seat and designed for use as passenger entertainment. Alternatively or additionally, one of the privacy displays can be arranged opposite a driver seat and designed for use as driver entertainment during autonomous driving or in a parked vehicle. 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:

[0026] Figure 1 shows a vertical longitudinal section of a section of a vehicle with an integrated privacy display in its preparatory construction stage, in which a simple transparent cover panel allows the projector light to pass through unaffected; and

[0027] Figure 2 shows a vertical longitudinal section of a section of a vehicle with a privacy display according to an embodiment of the invention, with a schematic representation of the beam path of the projector light deflected by its prism-shaped cover plate.

[0028] All of the various embodiments, alternatives, and specific design features of the privacy display 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 1 and 2, 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 1 and 2.

[0029] Fig. 2 shows, in a highly simplified schematic longitudinal sectional view, an embodiment of a vehicle 1 with a privacy display 2 of the type presented herein. In this example, the vehicle 1 is a motor vehicle, which is indicated in Fig. 2 only by its windshield 3 and an instrument panel 4 extending beneath it. As already mentioned, the spatial orientation terms such as "above," "below," "side," "horizontal," "vertical," etc., refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical axes of the vehicle 1.

[0030] The privacy display 2 is integrated inside the instrument panel 4 and contains an image generator 5 designed to generate a light beam L with the desired display content and a cover plate 6 designed to transmit the light beam L. The light beam L (projector light) is indicated in a highly simplified manner by its edge rays.

[0031] The cover panel 6 is formed in a surface section 4a of the instrument panel 4 facing a vehicle occupant in a front vehicle seat (not shown), so that its surface is arranged directly opposite the occupant. The occupant, in this example a front passenger, is only indicated by a spatial area E (eyebox) predetermined for their eyes or head. The eyebox E is again sketched purely symbolically and is located in the area of ​​the aforementioned vehicle seat.

[0032] Furthermore, the privacy display 2 comprises a projection and / or imaging optic arranged in the beam path of the projector light L between the imager 5 and the cover plate 6, which in this example comprises two directly opposite concave mirrors 7 and 8. These are designed purely as an example in Fig. 2 to project the display content generated by the imager 5 into a real image B floating freely in the air, which can be seen from the occupant's eyebox E when looking toward the cover plate 6.

[0033] By appropriately selecting the mutual arrangement and design of the image generator 5 and the projection and / or imaging optics, an optimal position (in terms of image distance) and orientation (in terms of image inclination) of the floating image plane between the cover screen 6 and the eyebox E can be achieved, which would not be possible with conventional display technologies such as flat screens or head-up displays. In particular, the occupant can view the real image B in a floating image plane at a comfortable reading distance between their vehicle seat and the instrument panel 4 without restricting their arm and legroom and without the image inclination depending on the geometry of the surface section 4a of the instrument panel 4. A similar approach can also be achieved for a virtual image display (not shown) beyond the cover screen 6.

[0034] The required radiation direction of the light beam L emerging from the cover plate 6 is predetermined by the vehicle geometry, namely by the mutual arrangement of the instrument panel 4 and the aforementioned vehicle seat with the associated eyebox E. Therefore, a space conflict may arise when designing the projection and / or imaging optics if, for example, a space area 9 required for this purpose within the instrument panel 4 is occupied by other vehicle equipment (not shown) or is not present.

[0035] Fig. 1 illustrates this problem in an auxiliary view showing the privacy display 2 of Fig. 2 in its preparatory design stage, in which a simple transparent cover plate 6 allows the light beam L to pass through unaffected. When integrating such a projector into the instrument panel 4, a space conflict may arise in the aforementioned space area 9 if it is needed for other purposes in the vehicle 1.

[0036] As shown in Fig. 2, this installation space conflict can be resolved by designing the cover panel 6 in a prism shape, in this example as a free-form prism only schematically indicated, which follows the outer shape of the instrument panel 4 and simultaneously also ensures that the light beam L is deflected upwards. This allows the installation space required for the privacy display 2 to be compressed vertically, thus freeing up the installation space area 9 required for another purpose. As described in more detail above, the free-form prism can additionally contribute to an optical improvement through a corresponding design of its free-form surfaces and / or to an improvement in contrast through the addition of particles, coloring or tinting, or through an integrated polarization filter.

[0037] List of reference symbols

[0038] 1 vehicle

[0039] 2 Privacy Display

[0040] 3 Windscreen

[0041] 4 Instrument panel

[0042] 4a Surface section of the instrument panel facing a vehicle occupant in a front vehicle seat

[0043] 5 imagers

[0044] 6 Cover plate

[0045] 7, 8 facing concave mirrors

[0046] 9 otherwise occupied construction space area

[0047] L Light beam, also called projector light

[0048] B real image floating in the air

[0049] E Eyebox

Claims

Claims 1. Compact privacy display (2) for installation in an instrument panel (4) of a vehicle (1), comprising: 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 to be arranged in a surface section (4a) of the instrument panel (4) which faces a vehicle occupant on a front vehicle seat; and projection and / or imaging optics arranged in the beam path between the image generator (5) and the cover plate (6), which projection and / or imaging optics are designed to display the display content as a real image (B) or a real image (L) floating freely in the air in front of or behind the cover plate (6).virtual image is formed; wherein the cover plate (6) is designed in a prism shape for deflecting the light beam (L) upwards in order to vertically compress an installation space required for the privacy display (2) and thereby output the light beam (L) directly in the direction of a spatial region (E) predetermined for the eyes of said occupant.

2. Privacy display (2) according to claim 1, wherein the prism-shaped cover plate (6) is designed as a free-form prism with a free-form surface facing the occupant and / or the projection and / or imaging optics, which can be adjusted to a predetermined Surface geometry of the instrument panel (4) and / or is designed for an additional image-correcting and / or imaging effect.

3. Privacy display (2) according to claim 1 or 2, wherein the prism-shaped cover plate (6) has an at least approximately triangular shape in a vertical longitudinal section, preferably tapering downwards.

4. Privacy display (2) according to one of the preceding claims, wherein the cover plate (6) is darkened by particle addition, coloring or tinting, or by a polarization filter to such an extent that a direct view into the interior of the privacy display (2) for vehicle occupants is essentially prevented and at the same time a contrast medium for displaying the real or virtual image (B) with a sufficient contrast is created.

5. The privacy display (2) according to claim 4, wherein the polarization filter is designed as a circular polarizer composed of an λ / 4 retarder facing the projection and / or imaging optics and a linear polarizer facing the occupant; and the imager (5) is preferably designed to output the light beam (L) with such a circular polarization that, after passing through the λ / 4 retarder, it has a linear polarization transmitted by the linear polarizer.

6. Privacy display (2) according to one of the preceding claims, wherein the projection and / or imaging optics comprise at least one concave mirror (7, 8).

7. Privacy display (2) according to claim 6, wherein the projection and / or imaging optics comprise two concave mirrors (7, 8) directly opposite one another in the beam path of the light beam (L).

8. A vehicle (1) with mutually perpendicular longitudinal, transverse and vertical axes of a Cartesian coordinate system fixed to the vehicle, in particular a motor vehicle, comprising: a windscreen (3), an instrument panel (4) extending thereunder and at least one front vehicle seat arranged opposite the instrument panel (4); and at least one privacy display (2) according to one of the preceding claims, which is integrated into the instrument panel (4) in such a way that its cover panel (6) forms a surface section (4a) of the instrument panel (4) facing a vehicle occupant on one of the front vehicle seats.

9. Vehicle (1) according to claim 8, wherein the cover plate (6) is arranged in the instrument panel (4) such that its user-side surface is flush with adjacent surface sections of the instrument panel (4).

10. The vehicle (1) according to claim 8 or 9, wherein one of the privacy displays (2) is arranged opposite a passenger seat and is designed for use as passenger entertainment; and / or one of the privacy displays (2) is arranged opposite a driver seat and is designed for use as driver entertainment during autonomous driving or in a parked vehicle (1).

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