Head-up display with curved image generator for reflecting planar virtual image through front glass direct mirror

Abstract

The invention relates to an image generator for use in a vehicle, which is designed to insert a planar virtual image into the field of view of at least one vehicle occupant by reflection at a vehicle glass; the invention relates to a display device for a vehicle, comprising a vehicle glass and an image generating surface, in which a respective desired display content is generated as a real image, and which is designed to be arranged opposite the vehicle glass such that the display content is directly mirror-reflected from the vehicle glass to the eyes of at least one occupant. Wherein the image generating surface has a curvature at least in one direction, which curvature at least partially resists the interfering influence of the concave vehicle glass shape on the virtual image to be presented in a planar manner.

Description

Technical Field

[0001] The present invention relates to an image generator for a visual field display device for use in a vehicle. The visual field display device is configured to insert a virtual image into the visual field of at least one vehicle occupant by reflection from the vehicle window. Visual field display devices of this type are also known as heads-up displays (HUDs). The present invention also relates to a visual field display device and a vehicle equipped with the visual field display device, which can be configured, for example, as a motor vehicle or other type of land, air, or water vehicle. Background Art

[0002] For example, in motor vehicles, heads-up displays (HUDs) can be used to superimpose speed information and other useful navigation, warning, and vehicle operating instructions in the form of virtual images on the real environment ahead of the vehicle, as viewed by the driver and / or other occupants. This also allows passengers to be presented with entertainment content, such as videos and other content, during their journey. In particular, for producing large-area or panoramic virtual presentations, a simplified HUD design type is known in which the image generator is positioned directly opposite the windshield in its root region, without additional imaging or projection optics, such as mirrors. This is often referred to as a "mirrorless HUD."

[0003] Figure 1a A highly simplified perspective view from obliquely above shows a detail of a vehicle 10 having a mirrorless HUD 20 according to the prior art. In this simplified HUD design, the real image 40 generated by its image generator 30 in its image generation surface 80 is directly reflected by a mirror in the windshield 50 of the vehicle 10 and thereby reaches the eyes 60 of an observer (e.g., the driver and / or passenger). As a result, a virtual image 70 appears in the observer's field of view on the other side of the windshield 50. The relevant light beam L is Figure 1a denoted by its central ray, which is directed from the center of image generating surface 80 to the center of a spatial region (eye box) predetermined for eye 60 of the respective observer in the passenger space of vehicle 1 .

[0004] Today's head-up display systems typically use flat screens as image generators. In most cases, LCD displays (liquid crystal displays) with highly focused, bright backlighting are used. The virtual image generated by reflection from the front window should also appear as flat and stable as possible within a limited viewing area. Aspherical mirrors are often used to compensate for optical influences of the front window, which can, for example, cause distortions in the virtual image.

[0005] like Figure 1aAs shown in FIG, in the case of a mirrorless HUD 20, no mirror is available to compensate for imaging errors or image deformations caused by the curvature of the front glass. Here, in the first method, only the real two-dimensional image 40 (in Figure 1a Image pre-correction (purely schematically indicated in FIG) is applied to the planar image generation surface 80 of the image generator 30 so that the virtual image 70 still appears as flat and rectangular as possible to one or more observers. However, depending on the geometry of the windshield 50, the virtual image 70 is deformed to varying degrees in the longitudinal direction of the vehicle. Figure 1a As shown in FIG, under common front glass curvatures, the virtual image 70 is convex in the vertical direction from the occupant's perspective and concave in the horizontal direction from the occupant's perspective. This characteristic can be particularly disruptive when long linear objects are presented in the HUD 20. Summary of the Invention

[0006] The object of the present invention is to provide an alternative and / or improved concept for HUD systems in vehicles with regard to installation space, presentation possibilities, presentation quality and / or other aspects.

[0007] This object is achieved by an image generator according to claim 1 and by a field of view display device comprising the image generator and a vehicle equipped with the field of view display device according to the coordinated claims. Further refinements are provided in the dependent claims. All the features and effects mentioned in the claims and in the following description for the image generator also apply to the field of view display device and the vehicle, and vice versa.

[0008] According to a first aspect, an image generator for use in a vehicle is provided. The vehicle may be, in particular, a motor vehicle, but may also be any other land, air, or water vehicle. Unless otherwise specified, all positional descriptions and spatial orientation terms used herein, such as "vertical," "horizontal," "left," "right," "front," "rear," "below," "above," etc., refer to a conventional Cartesian coordinate system fixed to the vehicle, having a longitudinal direction, a transverse direction, and a height direction of the vehicle that are perpendicular to one another.

[0009] An image generator is designed to insert a largely flat virtual image into the field of view of at least one vehicle occupant by reflection off a vehicle window. The image generator includes an image generation surface in which the desired display content can be generated as a real image. The image generation surface is designed to be arranged opposite the vehicle window so that the display content is directly reflected from the vehicle window into the eye or eyebox of at least one occupant, i.e., without any additional redirecting or imaging optics in the beam path between the image generator and the occupant. Thus, the image generator and the vehicle window together form a field of view display device, in particular a head-up display (HUD), of the simplified (mirrorless) design type mentioned above. As is common practice, an eyebox is understood here to be a two- or three-dimensional spatial region in the vehicle from which a virtual image of a specified quality is visible.

[0010] The vehicle window can be, in particular, a front window, but can alternatively also be a rear window or side window of the vehicle. As is common, the vehicle window is concavely curved on the inside of the vehicle. Here, the image generation surface is also curved in at least one direction to reduce or compensate for any disruptive effects of the curvature of the vehicle window on the virtual image to be presented in a planar manner, at least in one direction (e.g., horizontally or vertically). In other words, the curvature of the image generation surface is designed to at least partially counteract undesirable distortions of the displayed content when it is reflected on the concavely curved inner surface of the vehicle window, which would cause the virtual image to appear uneven and have distorted angular proportions.

[0011] Therefore, one idea of the proposed display concept is to minimize the aforementioned problem of disruptive bending / distortion of the virtual image intended to be presented flatly due to the curvature of the front window, even in the case of a mirrorless HUD, by using a curved image generator. For example, the image generating surface of the image generator can have a curvature shape that is suitably inverted relative to the shape of the front window, or that compensates for it, at least in one direction. In this way, the virtual image can be "flattened." The aforementioned two-dimensional "pre-correction" of the real image in the image generating surface can optionally (but not necessarily) be used to further support this effect.

[0012] In particular, the curvature of the image generating surface can be specifically tailored to a predetermined vehicle window geometry in order to achieve the best possible result for the virtual image. Alternatively, however, the curvature of the image generating surface can also be adapted to a plurality of different vehicle windows by being optimized, for example, for an average vehicle window, thereby also resulting in a significant improvement over the prior art.

[0013] As mentioned at the beginning and Figure 1a As shown in , with conventional windshield curvatures, the virtual image is convex in the vertical direction from the perspective of the occupant and concave in the horizontal direction from the perspective of the occupant. To reduce or compensate for this image area curvature, the image generating surface can, for example, be concavely curved in a first direction and convexly curved in a second direction that is independent of the first direction, in particular, orthogonal to the first direction.

[0014] The solution presented here is particularly important for visual field displays or heads-up displays that feature large virtual images (e.g., for panoramic presentations) and / or are viewable by multiple vehicle occupants simultaneously. For different viewing positions, such as those of the driver and front passenger, the aforementioned image pre-correction alone can only moderately mitigate the effects of a curved virtual image, as it can only be optimized for a specific viewing position. With large virtual images, the relationship between the image area and image size becomes less favorable and therefore more noticeable. In these applications, a flat virtual image can also be generated by curvature of the image generator that counteracts the curvature of the window.

[0015] In principle, any image generation technology is suitable for the image generator. For example, the image generator can be designed as a display having a two-dimensional matrix of electrically controllable pixels, which forms the image generation surface. In particular, the image generator can be a flat screen that transmits or emits light, such as a liquid crystal display (LCD), a µLED display, or an OLED display. Alternatively, however, the image generator can also be a projector-based image generator comprising a projector for generating a light beam with the desired display content and a projection screen (also referred to as a screen) illuminated by the projector, which forms the image generation surface.

[0016] According to one embodiment, the image generating surface is cylindrically curved. For example, if the image generator can only be cylindrically curved due to technical or installation space reasons, this can minimize the curvature of the virtual image area in at least one direction. Compared to significantly more complex spherical or non-spherical shapes, a cylindrical embodiment of the image generator is easier to implement with most display technologies, especially display technologies such as LCD, OLED, or μLED. For example, when the virtual image content is reflected by a front mirror, the curvature of the image area in the vertical direction is generally more noticeable than in the horizontal direction. By utilizing the cylindrical curvature of the display surface in the corresponding direction, this curvature of the image area can be specifically reduced or eliminated.

[0017] According to another embodiment, the image generation surface is curved in two independent directions. For example, the image generation surface can be spherically or non-spherically curved. Its curvature characteristics can remain constant along its surface or vary from one point to another. This curvature characteristic is particularly well-achieved with image generators that use projection technology onto a light-scattering screen to generate the image. For example, the screen can be manufactured as a drawn scattering-reflecting film. Alternatively, the screen can also be designed as an optical injection-molded plate with a spherical or non-spherical curvature. For example, plastics with suitable properties are suitable as materials for such screens.

[0018] Furthermore, not only the cylindrical curvature of the image generator, but also its spherical or aspherical curvature can contribute to uniform illumination of the occupant's field of vision (eye box) through the resulting collimation effect. Furthermore, a cylindrically or spherically / aspherically curved image generating surface can offer installation space advantages compared to a flat image generating surface of the same size, by reducing the lateral dimensions of the cylindrically or spherically / aspherically curved image generating surface due to the curvature.

[0019] According to another aspect, a visual field display device for a vehicle is provided. The visual field display device comprises the image generator described herein and the vehicle window, which is concavely curved on the image generator side and is arranged or can be arranged in the beam path of a light beam output by the image generator during operation, such that the vehicle window reflects the display content generated by the image generator directly to the eye or eye box of at least one occupant. The curvature of the image generation surface is designed to reduce or ideally compensate for the influence of the curvature of the vehicle window on the virtual image, at least in this direction, so that the virtual image can be presented as rectilinear, angular, or planar as possible, at least with respect to this direction.

[0020] In particular, the image generating surface can have a curvature shape that is inverted relative to the vehicle window (or relative to the curvature of the image area caused by its curvature) in at least one direction so that the image generating surface compensates for the influence of the curvature of the vehicle window on the virtual image at least in this direction.

[0021] In the case of the aforementioned cylindrical curvature of the image-generating surface, the cylindrical axis of the image-generating surface can be oriented along its front edge closest to the vehicle window or along the base of the window, and the curvature can be concave from the perspective of the occupant (or when viewed from the vehicle window). This can reduce or compensate for the aforementioned image area doming around the horizontal image axis. Alternatively, the cylindrical axis of the cylindrically curved image-generating surface can be oriented along its side edge or orthogonal to the base of the window, and the curvature of the image-generating surface can be convex from the perspective of the occupant (or when viewed from the vehicle window). This can reduce or compensate for the aforementioned concave image area doming around the vertical image axis.

[0022] A combination of these two variants is also possible in the case of non-spherically curved image-generating surfaces.

[0023] According to another aspect, the aforementioned vehicle is provided. The vehicle includes a passenger compartment and a vehicle window, particularly a windshield, that at least partially delimits the passenger compartment. Furthermore, the aforementioned visual field display device is provided in the vehicle. The image generator of the visual field display device is arranged in the passenger compartment, particularly in an instrument panel below the windshield, and the vehicle window of the visual field display device is the vehicle window of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above aspects of the invention and their embodiments and specific designs are explained in more detail below with the aid of examples shown in the accompanying drawings. The drawings are primarily schematic and therefore should not be understood as being true to scale. The drawings show:

[0025] Figure 1a A perspective view shows a detail of a vehicle having a conventional mirrorless HUD, the virtual image of which has an image field curvature and is to be presented in a planar manner;

[0026] Figure 1b A perspective view showing a partial portion of a vehicle having a visual field display device according to an embodiment of the present invention, which can realize a virtual image presentation of a plane;

[0027] Figure 2a Show Figure 1a a vertical longitudinal sectional view of the transport vehicle; and

[0028] Figure 2b A vertical longitudinal sectional view of a vehicle having a field of view display device according to another embodiment of the present invention is shown, which can realize a straight line or plane virtual image presentation in the vertical direction. DETAILED DESCRIPTION

[0029] All the different embodiments, variants and specific design features of the image generator, the field of view display device and the means of transport according to the above aspects of the invention mentioned above in the description and in the claims below can be Figure 1b and Figure 2b The examples shown in FIG are implemented, in particular also instead of or in addition to the features shown therein. Therefore, not all of them are repeated again below. The same also applies to the already described above and Figure 1b and Figure 2b Definitions of terms and effects related to the individual features shown in.

[0030] Figure 1b A highly simplified perspective view from obliquely above shows a detail of a vehicle 1 having a field of view display device 2 according to an embodiment of the present invention. The spatial orientation terms used below, such as "horizontal," "vertical," "above," "below," "beneath," etc., relate to a conventional Cartesian coordinate system K fixed to the vehicle, which has a longitudinal direction, a transverse direction, and height directions X, Y, and Z of the vehicle 1 that are perpendicular to one another.

[0031] In this example, the vehicle 1 is a motor vehicle, which is shown in FIG1 only by its windshield 5, which forms part of the field of view display device 2. Below the windshield, on the dashboard (not shown in detail), the image generator 3 of the field of view display device 2 is arranged. In this example, the basic structure involves a mirrorless HUD, the conventional design of which has been described at the outset. Figure 1a Described.

[0032] In this simplified HUD design, the real image 4 generated by the image generator 3 in its image generation area 8 is directly reflected in the windshield 5 and thereby reaches the eyes 6 of the observer (e.g. the driver and / or co-driver of the vehicle 1). As a result, a virtual image 7 appears in the observer's field of view on the other side of the windshield 5. The relevant light beam L is Figure 1b denoted by its central ray, which is directed from the center of image generation surface 8 to the center of a spatial region (eye box, not shown) predetermined for the eyes of the respective occupant in the passenger space of vehicle 1 .

[0033] According to Figure 1a Unlike conventional embodiments of the image generating surface 80 having a plane, Figure 1bThe image generating surface 8 of the image generator 3 is of curved design and, in this example, has a curvature shape that is inverted with respect to the windshield 5. Here, the image generating surface 8 is concavely curved in a first direction (about a first axis of curvature extending approximately in the vehicle transverse direction Y) and convexly curved in a second direction independent of the first direction (about a second axis of curvature extending approximately in the vehicle longitudinal direction X). In this way, Figure 1a In contrast, the virtual image 7 can be "flattened", that is, the Figure 1a In the virtual image 70 , an undesired curvature of the image area is caused by the curvature of the front window.

[0034] If, for technical or installation space reasons, the image generator 3 can only be curved cylindrically, the curvature of the virtual image area can be minimized in at least one direction. Figure 2a and Figure 2b An example is given to illustrate:

[0035] Figure 2a Shown again Figure 1a 10 , wherein the edge rays of the light beam L are additionally indicated, which facilitates the virtual image generation. In this view, the typical convex curvature of the virtual image 70 mentioned above in the vertical direction or height direction Z of the vehicle 10 , which results from the conventional windshield geometry, can be clearly seen.

[0036] Figure 2b Also shown is a vertical longitudinal section of a vehicle 1 having a visual field display device 2 according to another embodiment of the present invention, which is similar to the embodiment of the present invention. Figure 2a Different virtual images can be presented that are flattened in the vertical direction (i.e., in the height direction Z of the vehicle 1). For this purpose, the image generating surface 8 of the image generator 3 is designed with a cylindrical curvature that is inverted in a suitable manner relative to the curvature of the windshield, with the cylinder axis of this cylindrical curvature extending approximately along the glass root of the windshield 5. In addition, to avoid repetition, reference is made to the above description of the Figure 1b description, which can also be applied to Figure 2b Here, in Figure 2b In addition, marginal rays of the light beam L that contribute to the virtual image generation are also marked.

[0037] Reference Signs List

[0038] 1. Transportation

[0039] 2 Field of view display device

[0040] 3 Image Generator

[0041] 4 Real images

[0042] 5 front glass

[0043] 6Observer / Occupant's Eyes

[0044] 7 Virtual Images

[0045] 8 Image Generator Image Generation Surface

[0046] L-beam

[0047] K is a Cartesian coordinate system fixed at the transport vehicle

[0048] X, Y, Z transport longitudinal, transverse and height directions

[0049] 10 Traditional means of transportation

[0050] 20 Traditional mirrorless HUD

[0051] 30 Image Generator

[0052] 40 real images

[0053] 50 front glass

[0054] 60 Observer / Occupant's Eyes

[0055] 70 virtual images

[0056] Image generation surface of 80 image generator

Claims

1. An image generator (3) for use in a transport vehicle (1), the image generator (3) - configured to insert a substantially planar virtual image (7) into the field of vision of at least one vehicle occupant by reflection on a vehicle window; and - having an image generating surface (8) in which the corresponding desired display content can be generated as a real image (4), and the image generating surface is designed to be arranged opposite the vehicle window so that the display content is directly reflected from the vehicle window to the eye (6) of at least one occupant; wherein the image generating surface (8) has a curvature in at least one direction, which at least partially counteracts the disruptive influence of the concave vehicle window shape on the virtual image (7) to be presented in a planar manner.

2. The image generator (3) according to claim 1, wherein - The image generating surface (8) is cylindrically curved.

3. The image generator (3) according to claim 1, wherein - The image generating surface (8) is curved in two independent directions.

4. The image generator (3) according to claim 3, wherein The image generating surface (8) is concavely curved in a first direction and convexly curved in a second direction independent of the first direction.

5. Image generator (3) according to any one of the preceding claims, The image generator is designed as a display having a two-dimensional matrix of electrically actuatable pixels, which forms the image generation surface (8); or The image generator is designed as a projector-based image generator having a projector for generating a light beam and a projection screen illuminated by the projector, the projection screen forming the image generation surface (8).

6. A visual field display device (2) for a transportation vehicle (1), comprising: - an image generator (3) according to any one of the preceding claims; as well as a vehicle window that is concavely curved on the image generator side, said vehicle window being arranged or capable of being arranged in the beam path of the light beam (L) output by the image generator (3), so that said vehicle window reflects the display content generated in the image generating surface (8) directly to the eye (6) of at least one occupant; - wherein the curvature of the image generating surface (8) reduces or compensates for the influence of the curvature of the vehicle window on the virtual image (7) at least in the direction, so that the virtual image can be presented as a substantially straight line or a plane at least with respect to the direction.

7. The visual field display device (2) according to claim 6, wherein: The image generating surface (8) has a curvature shape that is inverted relative to the vehicle window in at least one direction, in order to compensate for the influence of the curvature of the vehicle window on the virtual image (7) at least in this direction.

8. The visual field display device (2) according to claim 6 or 7 in combination with claim 2, wherein: - the cylindrical axis of the cylindrically curved image generating surface (8) is oriented along its front edge closest to the transport window or along the glass root of the transport window, and the curvature of the image generating surface (8) is concave when viewed in the direction of the transport window; or The cylindrical axis of the cylindrically curved image generating surface (8) is oriented along its side edge or orthogonally to the glass root of the vehicle window, and the curvature of the image generating surface (8) is convex when viewed in the direction of the vehicle window.

9. The visual field display device (2) according to claim 6 or 7 in combination with claim 3, wherein: - the first axis of curvature of the image generating surface (8) is oriented along its front edge closest to the transport glass or along the glass root of the transport glass, and the associated curvature of the image generating surface (8) is concave when viewed in the direction of the transport glass; and The second axis of curvature of the image generating surface (8) is oriented along its side edge or orthogonally to the glass root of the vehicle window, and the associated curvature of the image generating surface (8) is convex when viewed in the direction of the vehicle window.

10. A vehicle (1), in particular a motor vehicle, having a Cartesian coordinate system (K) fixed to the vehicle, with longitudinal, transverse and height directions (X, Y, Z) perpendicular to one another, the vehicle comprising: a passenger space having a vehicle window, in particular a front window (5), which at least partially delimits the passenger space; as well as - A field of view display device (2) according to any one of claims 6 to 9, wherein the image generator (3) of the field of view display device is arranged in the passenger space, in particular in the instrument panel arranged below the front glass (5), and the vehicle glass of the field of view display device is the vehicle glass of the vehicle (1).

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