Head-up display with a composite, conveyor-belt-like display area, especially for a vehicle

Abstract

The invention relates to a projection unit for a field-of-view display device, designed to project a virtual image by reflection off a reflective surface, in particular a vehicle windshield, located in the user's field of vision. The projection unit comprises an image-generating display surface, which is to be arranged in or below the upper surface of a vehicle's instrument panel and is composed of several rectangular sub-areas. Each of these sub-areas is formed by an associated mechanically movable strip with at least one light source strip attached to it, extending transversely to its direction of movement and carrying light sources arranged in series along its extension. These light sources can be controlled synchronously with the strip's movement and independently of one another to generate a desired display content in the display surface.

Description

[0001] The invention relates to a projection unit for a head-up display (HUD) device, which is also known as a head-up display (HUD) and can be used in particular in a motor vehicle or other land, air, or water vehicle. Head-up display devices of this type are designed to generate a virtual image superimposed into the user's field of vision via reflection from a vehicle window, in particular a windshield, or from a combiner window provided specifically for this purpose and arranged in the user's field of vision. The invention also relates to such a head-up display device and to a vehicle equipped therewith.

[0002] Particularly in motor vehicles, it is well known that a head-up display (HUD) overlays information such as speed limit information or other useful navigation and vehicle operating instructions in the form of a virtual image onto the real surroundings in front of the vehicle as observed by the driver, so that the driver does not have to take their eyes off the road to read the information. To generate the display content, a conventional HUD comprises a projection unit located below the windshield inside the instrument panel.This typically includes a display for generating a light beam with the desired display content, as well as imaging and projection optics, usually with a concave mirror, to shape the light beam and direct it onto the windshield so that it is reflected back to the driver's eyes, allowing them to see the virtual image at a suitable size and distance beyond the windshield. However, the dimensions of the concave mirror scale linearly with the size of the virtual display area, which severely limits it.

[0003] Alternatively, for applications requiring a significantly larger virtual display area, a HUD design with a large-area display extending directly opposite the windshield on the upper surface of the instrument panel is known. This is particularly suitable for future fully automated or autonomous vehicles, which are intended to operate without user input from the driver, so that the associated entertainment systems in the passenger compartment are becoming increasingly important. For example, with a HUD of this type, one would want to display additional information to a driver and / or a passenger across the entire width of the windshield, depending on the situation and the external environment, and, if necessary, also display a continuous panoramic virtual image. For this to happen, the image-generating display would have to extend across the entire width of the windshield.

[0004] To meet the high intensity requirements for display light reflected in the transparent area of ​​the windshield in broad daylight, an LED display would be more suitable than a liquid crystal display because high intensity losses in the liquid crystal layer are unavoidable. However, such a large display area would require an excessive number of LEDs (several million), which in turn would have a significant impact on the vehicle's energy balance and associated greenhouse gas emissions. A possible display size for a panoramic view is 1200 mm (length) by 300 mm (width), for a 4:1 ratio. Using a conventional display, this would require the installation of approximately 2,000,000 LEDs. These are arranged in approximately 1920 columns across the width of the HUD display. This large number of LEDs would generate greenhouse gas emissions of more than 1.2 CO2 equivalents.

[0005] Rotating display devices with a circular display surface that can be generated by rotation are known in the prior art, for example for design and toy items or greeting cards, as described, for example, in US Pat. No. 9,190,028 B2 or EP 4 030 412 A1. Such a rotating display device comprises a fixed motor, to the motor shaft of which a rotating unit is attached, which is rotated by the motor. The rotating unit is designed as at least one rod-shaped arm arranged in the radial direction, with an LED strip attached longitudinally to the arm. Suitable rotation or position sensors are provided to synchronize the LED control with the rotation of the arm. Depending on the embodiment, this display device can, for example, comprise a single radial arm, two individual radial arms spaced 180° apart, or four individual radial arms spaced 90° apart.Similarly, WO 2019 / 023489 A1 discloses an apparatus and method for displaying an image generated by the emission or reflection of light by rotating elements such as fan blades.

[0006] Furthermore, WO 99 / 35634 discloses a rotating display arrangement with a round, elongated, oval, or polygonal cross-section and a plurality of display elements evenly distributed on a moving belt forming a peripheral surface of the arrangement. To realize several different radiation directions, partition walls with different inclinations can be provided between the individual display elements. US 2004 / 0212572 A1 discloses a similar display arrangement, wherein here, too, a movable belt is wound around one or more parallel axes of rotation arranged at the corners of a correspondingly polygonal cross-section. Modern vehicles typically include an air conditioning system, with a fan located in the instrument panel distributing air to the passenger compartment. The air conditioning fan requires a significant amount of space in the instrument panel, forcing space compromises with other instruments and devices that must also be housed in the instrument panel.

[0007] The object of the present invention is to provide an alternative and / or improved design concept for a field-of-view display device with regard to energy balance, required installation space, and / or cost-effectiveness, which also enables the generation of a large-area virtual image, for example, for a panoramic display. In particular, this field-of-view display device should be suitable for integration into a vehicle and for virtual display via reflection on its windshield.

[0008] This object is achieved by a projection unit according to claim 1, as well as a visual field display device 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 projection unit also apply to the visual field display device and the vehicle, and vice versa.

[0009] According to a first aspect, a projection unit for a field-of-view display device is provided, which can be designed in particular for use in a vehicle. The field-of-view display device is designed to project a virtual image into a user's field of vision via reflection from a reflective panel arranged in the user's field of vision, in particular a vehicle window. It can be designed, for example, as a head-up display (HUD).

[0010] During operation of the field-of-view display device, the projection unit is designed to generate a projection light beam (short: "projection light") with a desired display content and project it onto the aforementioned reflection plate, whereby the desired virtual image appears to the user as floating beyond the reflection plate. The user can be, in particular, a driver and / or front passenger, but also other occupants of the vehicle.

[0011] For this purpose, the projection unit comprises an imaging display surface, which can be designed, in particular, for placement in or beneath the upper surface of an instrument panel or parcel shelf of the vehicle. The display surface is composed of several rectangular individual areas and, to save material and energy resources, is designed according to a conveyor belt concept. Each rectangular individual area comprises an associated mechanically movable belt (also referred to herein as a "conveyor belt") with at least one light source strip attached thereto, which extends transversely to the belt's direction of movement and carries light sources, for example, LEDs, arranged in a row along its extension direction.

[0012] During operation, the light source strips are moved along the respective belt like a conveyor belt, thus covering the corresponding rectangular individual area of ​​the display surface. The respective light source strip can, for example, have the length (or width) of the individual area and, using the belt movement, be moved back and forth across its entire width (or length) or "rotated" in a constant direction of belt movement so quickly that the human eye cannot discern the temporal movement. To generate the desired display content in the display surface, the light sources can be controlled synchronously with the belt movement and independently of one another.

[0013] The rectangular individual areas can be identical to one another or can be designed differently in their shape and / or size and / or features, for example in order to optimally meet varying requirements for display properties or installation space along the display area.

[0014] One idea behind this projection unit is to replace a large, high-intensity, image-generating display surface in a field-of-view display device, such as a HUD, which can be designed for use in a vehicle, with a conveyor-type display surface known only from other applications. This allows the number of LEDs required in the HUD display surface to be significantly reduced. Despite the additional rotary drive consumption for the conveyor belt, a significant improvement in the vehicle's energy balance and thus a reduction in greenhouse gas emissions can be achieved. If the vehicle includes a battery-electric drive, a correspondingly greater range can be achieved.

[0015] A further idea involves dividing the desired display area into several independent individual areas. In order to achieve a sufficiently high frame rate with a single conveyor belt of the type described above, the conveyor belt would have to operate at a very high speed, especially when it comes to a panoramic display. Dividing the required display area into several individual areas, each with its own conveyor belt, opens up many new possibilities, both from a geometric perspective and for control. For example, by using several smaller individual areas, the rotation speed of the respective conveyor belts can be significantly reduced. In addition, entire individual areas can be switched on and off as needed during operation to save energy, or their display properties can be selectively adjusted.In addition, such a display area is easily scalable by adding additional rectangular individual areas and, thanks to its modular design, can be flexibly adapted to the geometric requirements of different applications.

[0016] According to one embodiment, the projection unit comprises, for each rectangular individual region, two parallel belt rotation axes extending along its opposite edges, i.e., rectangle sides, as well as a rotary drive designed to rotate at least one of the two belt rotation axes. The belt forms a loop that is stretched between the two belt rotation axes and wound around them, wherein the at least one belt rotation axis that can be rotated by the rotary drive is designed to entrain the belt to generate the aforementioned belt movement. This can be, for example, a belt conveyor. The light source strips can, for example, extend parallel to the rotation axes.

[0017] As already mentioned, the lengths and orientations of the individual light source strips can, in particular, correspond to a length or a width of the respective rectangular individual region. Alternatively or additionally, the rectangular individual regions in the composite display area can essentially directly adjoin one another along their respective lengths and / or widths and be arranged such that the strips and light source strips of the adjacent individual regions are aligned parallel to one another and are movable. In this case, the merging individual regions can, for example, also share strip rotation axes, thereby reducing the number of required rotary drives and resulting in consistently synchronous movement of the individual strips. This can be particularly useful for creating a coherent panoramic display.However, if the individual areas are used for independent content and display types or for different users (e.g. driver and front passenger or several users sitting next to each other), they can also be designed and arranged independently of each other.

[0018] Furthermore, the projection unit can optionally comprise a cover plate that extends along the imaging display surface in the beam path of the projection light emanating from it and is designed to transmit the projection light essentially without loss, while at least partially sealing and protecting the projection unit from the outside. The cover plate can serve, among other things, to prevent a vehicle occupant from interfering with moving elements of the display surface and can optionally be equipped with additional mechanical and / or optical functions. It can be made of any suitable material, for example, glass or transparent plastic such as acrylic glass, etc.

[0019] According to one embodiment, the strip has a plurality of slats arranged on the outside, i.e., on the same side as the light source strips, which slats can, for example, be evenly distributed along the strip's direction of travel. The slats extend parallel to one another and to the light source strips and are designed to impose a predetermined radiation direction on the projection light generated by the light source strips and / or to shield the display surface in other directions. For this purpose, the slats can be spatially oriented substantially parallel to one another, particularly across the entire display surface. They can, for example, be light-absorbing or coated to block light rays in directions other than the desired radiation direction.

[0020] In a specific development of this embodiment, the individual movable belts are designed as cross-flow fans with ventilation slots running parallel to the slats and are thus configured for simultaneous use as fans and / or blowers of an air conditioning system during operation of the projection unit. Suitable air intake, air guidance, and / or air outlet openings and surfaces can be configured inside the projection unit and / or in its housing or cover panel, which are configured to guide and, if necessary, distribute the air into predetermined air ducts. The individual air ducts can be configured, for example, to cool the display surface and the moving elements and / or as window heating and defrosting and / or for air conditioning the passenger compartment when used in a vehicle.

[0021] If the louvres are designed, as described above, to provide privacy for the light source strips, an additional cover plate and / or adjustment of the geometry between the display surface in the upper part of the instrument panel and the driver's line of sight are not required. In this case, the louvres extend approximately parallel to the reflective plate, making this arrangement of the louvres and strip movement ideal for the above-mentioned climate control concept, particularly for window heating and defrosting.

[0022] According to a further aspect, the above-mentioned field of view display device is provided, which, in addition to a projection unit presented herein, further comprises a reflection plate mentioned above, which can be formed, for example, by a vehicle window or designed as a specially provided combiner plate. The reflection plate is arranged in the beam path of the projection light emitted by the projection unit. It is reflective towards the user and can, in particular, be at least partially transparent to the ambient light incident from behind, so that the virtual image is superimposed on the real environment observed by the user through the reflection plate. The reflection plate is arranged and configured in the user's field of view such that it reflects the projection light to an eyebox predetermined for the user's eyes, thus allowing the display content to be presented to the user in the form of a virtual image beyond the reflection plate.

[0023] In the embodiment described above, the slats can extend in particular approximately parallel to the reflection disc and, when installed in a vehicle, for example, to its windscreen in order to conceal the view of the light source strips from the users or occupants and to emit the projection light only in the required direction towards the reflection disc.

[0024] According to a further aspect, the above vehicle is provided, which may, for example, be a motor vehicle or any other land, air, or water vehicle. It has a passenger compartment and a vehicle window that at least partially delimits it towards the outside. The vehicle window can, for example, be a windshield with an instrument panel arranged underneath it, or a rear window with a parcel shelf arranged underneath it. Unless otherwise stated, all spatial orientation terms used herein, such as “horizontal,” “vertical,” “above,” “below,” “beneath,” “front,” “rear,” “left,” “right,” etc., refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical directions of the vehicle. Furthermore, the vehicle comprises the above field of view display device, the projection unit of which is arranged in the passenger compartment, in particular in or underneath an upper side of the instrument panel orparcel shelf, and whose reflection disc is designed as part of the vehicle window or as a combiner disc arranged separately in the passenger compartment.

[0025] In particular, the windshield can be bounded to the left and right in the vehicle's transverse direction by an A-pillar of the vehicle, and the projection unit and its imaging display surface can be arranged in or below the upper side of the instrument panel in such a way that the windshield serves as a reflection plate of the field of view display device, at least over a large part of its extension in the vehicle's transverse direction. This makes it possible, in particular, to create a panoramic virtual display for the driver and / or front passenger. For this purpose, in particular, several rectangular individual areas of the type presented here can be arranged next to one another in the vehicle's transverse direction.

[0026] The above aspects of the invention and their embodiments and specific configurations are explained in more detail below with reference to examples shown in the accompanying drawings. The drawings are purely schematic and therefore not to scale. They show: Fig. 1 shows a section of a vehicle with a field of view display device according to an embodiment of the invention in a vertical longitudinal section; Fig. 2 a plan view of an imaging display surface composed of three individual areas of the field of view display device of the Fig. 1; Fig. 3a a cross-sectional view of one of the three individual areas of the imaging display area of ​​the Fig. 2; and Fig. 3b the individual area of Fig. 3a in top view.

[0027] All the various embodiments, variants and specific design features of the projection unit, the field of view display device and the vehicle according to the above aspects of the invention mentioned above in the description and in the following claims can be implemented in the Fig. 1 to 3b, in particular alternatively or in addition to the features shown therein. Therefore, they will not be repeated again below. The same applies accordingly to the definitions and effects already given above with regard to individual features that are described in the Fig. 1-3b are shown.

[0028] Fig. Figure 1 shows, in a highly simplified schematic representation in a vertical longitudinal section, a section of a vehicle 1 with a field of view display device 2 according to an exemplary embodiment of the invention. The field of view display device 2 is embodied here purely by way of example as a head-up display (HUD).

[0029] The field of view display device 2 serves to generate a virtual image V in the field of view of a user, for example a driver of the vehicle 1, which in the vertical longitudinal sectional view of the Fig. 1 is indicated only by his eyes 3 and a designated eyebox E in the passenger compartment of the vehicle 1. (As usual, the eyebox is understood here as a spatial area designated for the eyes of a user of the field of view display device 2, from which he can see the virtual image V in the intended display quality.) The vehicle 1 is purely exemplary of a motor vehicle. It is in Fig. 1 is indicated solely by its windscreen 4, an instrument panel 5 extending underneath it (not shown in detail) and a roof liner 6 extending above it.

[0030] The field of view display device 2 comprises a projection unit 7, which in this example is arranged below the windshield 4 in the instrument panel 5. The projection unit 7 is designed and arranged to generate and output a projection light beam L (hereinafter referred to as "projection light") with the desired display content in the direction of the windshield 4, so that it is reflected from the windshield 4 to the user eyebox E, allowing the user to see the virtual image V when looking into the windshield 4.

[0031] For this purpose, the projection unit 7 has an imaging display surface 8, which is arranged with its surface in or almost directly below an upper side of the instrument panel 5 and in Fig. 2 and Fig. 3a-3b is shown in more detail. The projection light L is in Fig. 1 is indicated solely by its central beam, which leads from a center of the imaging display surface 8 to a center of the eyebox E. The projection unit 7 can optionally additionally comprise a cover plate 11, which at least partially covers and protects the display surface 8 towards the front plate 4 and thereby transmits the projection light L emanating from it largely without loss.

[0032] As in Fig. 2 in a plan view of the display surface 8 of the Fig. 1, the desired display area is divided into several individual areas 8a, 8b and 8c, here purely as an example three. Each of these individual areas 8a-8c is assigned a mechanically moved belt (conveyor belt) 10, for example a belt conveyor, which moves at least one light source bar (here an LED bar) 9 aligned orthogonally to its belt movement direction R. By dividing the imaging display surface 8 into three individual areas 8a-8c, for example, the possibility of separately displaying content for the driver (left, individual area 8a), the front passenger (right, individual area 8c) and in a common area (center, individual area 8b) is created. In this example, the belt movement direction R is aligned approximately in the longitudinal direction of the vehicle, although other orientations and arrangements of the individual areas 8a-8c relative to one another are also possible depending on the application.For example, the belt movement direction R of the respective conveyor belt 10 can also be oriented in the transverse direction of the vehicle, with a corresponding alignment of the light source strips 9. Also, the individual areas 8a-8c do not have to be as in . Fig. 2 all be designed identically.

[0033] Fig. 3a-3b show in a cross-sectional view ( Fig. 3a) and a top view ( Fig. 3b) shows a simplified basic structure of the individual area 8a of the imaging display area 8 of the Fig. 2. In this example, the other two individual areas 8b and 8c are similar or identical to this.

[0034] As in Fig. 3a, the individual area 8a comprises a conveyor belt 10 equipped with slats 14, which carries several light source strips 9. A total of four or more (not all shown) light source strips 9 are arranged on the conveyor belt 10, which can in particular be evenly distributed along the belt 10. As shown in the plan view of Fig. 3b, in this example, at any given time, there are typically two to three light source strips 9 in the individual area 8a of the display surface 8. With the aid of the conveyor belt 10, the light source strips 9, which in this example have a width of the individual area 8a measured in the transverse direction of the vehicle, are quickly moved back and forth over the entire length of the desired display area measured in the longitudinal direction of the vehicle and / or are always rotated in the same belt movement direction R. Each strip 9 carries light sources (not separately shown) arranged in a row in its longitudinal direction, in this example LEDs, which can be controlled independently of one another and synchronously with the belt movement to generate images in the imaging display surface 8.

[0035] To generate this conveyor belt movement, the projection unit 7 comprises in the individual area 8a two parallel belt rotation axes 12, which extend along two opposite edges of its rectangular area, as well as a rotary drive (not shown) which is designed to rotate at least one of the two belt rotation axes 12. As best seen in the cross-sectional view of the Fig. 3a, the band 10 forms a loop that is stretched between and wound around the two band rotation axes 12. In this example, both band rotation axes 12 have gear-like projections for driving the band 10 during their rotation. The band 10 has complementary projections on its inner surface facing the rotation axes 12, which engage positively between the gear-like projections of the rotation axes 12.

[0036] In this example, the conveyor belts 10 are designed as cross-flow fans with slats 14 arranged on their outer sides. In this way, the conveyor belts 10 also serve as fans of an air conditioning system for heating or defrosting the windscreen 4 and / or for cooling the projection unit 7. The slats 14 can, for example, run parallel to the light source strips 9 and be evenly distributed along the belt movement direction R, as shown in Fig. 3a.

[0037] All slats 14 in the display surface 8 are spatially oriented in the same way to each other in order to project light L (cf. Fig.1) in a predetermined radiation direction toward the windshield 4 and efficiently shield other viewing and radiation directions. In particular, the light source strips 9 are thereby shielded from the direct view of the vehicle occupants: Only the virtual image V produced by the field of view display device 2 via reflection in the windshield 4 is visible to the occupants.

[0038] Depending on the desired maximum displayable frame rate, the number of individual areas 8a-8c and the respective light source bars 9 carried per conveyor belt 10 can also be selected differently than in this example. List of reference symbols 1 vehicle 2 Field of view display device 3 User's eye 4 Windscreen 5 Instrument panel 6 headliner 7 Projection unit 8 imaging display area 8a, 8b, 8c Individual areas of the display area 9 Light source strip, especially LED strip 10 moving belt, also called assembly line 11 Cover plate 12 Belt rotation axis 14 slats E User's eyebox L Projection light (beam) R Belt movement direction V virtual image QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 9,190,028 B2

[0005] EP 4 030 412 A1

[0005] WO 2019 / 023489 A1

[0005] WO 99 / 35634

[0006] US 2004 / 0212572 A1

[0006]

Claims

[1] Projection unit (7) for a field of view display device (2) which is designed to display a virtual image (V) via reflection on a reflection plate arranged in the field of view of a user, in particular a vehicle window (4), comprising: - an imaging display surface (8) which is to be arranged in or under an upper side of an instrument panel (5) of a vehicle (1) and is composed of several rectangular individual areas (8a, 8b, 8c); wherein - each of these individual areas (8a, 8b, 8c) is formed by an associated mechanically movable belt (10) with at least one light source bar (9) fastened thereon, which extends transversely to its belt movement direction (R) and carries light sources arranged in a row in its direction of extension, which can be controlled synchronously with the belt movement and independently of one another to generate a desired display content in the display area (8). [2] Projection unit (7) according to claim 1, - further comprising, for each rectangular individual region (8a, 8b, 8c), two parallel belt rotation axes (12) extending on the opposite sides of the rectangle, and a rotary drive designed to rotate at least one of the two belt rotation axes (12); - wherein the band (10) forms a loop which is stretched between the two band rotation axes (12) and wound around them, wherein the at least one band rotation axis (12) rotatable by the rotary drive is designed to entrain the band (10) to generate the said band movement. [3] Projection unit (7) according to claim 1 or 2, wherein - Lengths and orientations of the light source strips (9) correspond to a length or a width of the respective rectangular individual area (8a, 8b, 8c). [4] Projection unit (7) according to one of the preceding claims, wherein - the rectangular individual areas (8a, 8b, 8c) in the composite display surface (8) adjoin one another along their respective lengths and / or widths and are arranged such that their associated bands (10) and light source strips (9) are aligned parallel to one another and are movable. [5] Projection unit (7) according to one of the preceding claims, wherein - the band (10) has a plurality of slats (14) arranged on the outside and preferably evenly distributed along the band movement direction (R), which extend parallel to one another and to the light source strips (9) and are designed to impose a predetermined radiation direction on the projection light (L) generated by the light source strips (9) and / or to shield the display surface (8). [6] Projection unit (7) according to claim 5, wherein - the slats (14) are spatially aligned substantially parallel to one another over the entire display surface (8). [7] Projection unit (7) according to claim 5 or 6, wherein - the individual movable belts (10) are designed as cross-flow fans with ventilation slots running parallel to the slats (14) and are thus designed for simultaneous use as a fan and / or as a blower of an air conditioning system during operation of the projection unit (7). [8] Field of view display device (2), in particular for use in a vehicle (1), comprising: - a projection unit (7) according to one of the preceding claims; and - a reflection disc arranged in the beam path of the projection light (L) emitted by the projection unit (7), such as a vehicle window (4) or a specially provided combiner disc; - wherein the reflection disc is arranged and designed in the field of vision of the user in such a way that it reflects the projection light (L) to an eyebox (E) predetermined for the user's eyes (3), whereby the display content can be presented to the user in the form of a virtual image (V) beyond the reflection disc. [9] Vehicle (1) with mutually perpendicular longitudinal, transverse and height directions of a vehicle-fixed Cartesian coordinate system, in particular a motor vehicle, comprising: - a passenger compartment and a vehicle window which at least partially delimits it towards the outside, in particular a windscreen (4) with an instrument panel (5) arranged underneath; and - a field of view display device (2) according to claim 8, whose projection unit (7) is arranged in the passenger compartment and whose reflection disc is designed as part of the vehicle window or as a combiner disc arranged separately in the passenger compartment. [10] Vehicle (1) according to claim 9, wherein - the projection unit (7) and its imaging display surface (8) are arranged in or below an upper side of the instrument panel (5) in such a way that the windscreen (4) serves as a reflection screen of the field of view display device (2) at least with a large part of its horizontal extent.

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