Projection unit for a field of view display device with a composite assembly line-like display surface, in particular for a vehicle, field of view display device and vehicle with such a

Abstract

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).

Description

The invention relates to a projection unit for a visual field display device, which is also known as a head-up display (HUD) and can be used in particular in a motor vehicle or another land, air or watercraft. Visual field display devices of this type are designed to generate a virtual image blended into the visual field of a user by reflection on a vehicle window, in particular a front window, or on a combiner window provided specifically for this purpose, which is arranged in the visual field of the user. The invention is also directed to such a visual field display device and to a vehicle equipped therewith.It is known, in particular for motor vehicles, by means of a head-up display to superimpose display contents such as information about speed limits or other useful navigation and vehicle operating instructions in the form of a virtual image of the real environment in front of the vehicle observed by the driver, so that he does not have to avert his gaze from the road in order to read this display. To generate the display content, an HUD of classic construction comprises a projection unit accommodated below the front screen in the interior of the instrument panel. This typically includes a display for generating a beam of light having the desired display content, and imaging and projection optics, usually with a concave mirror, for shaping and directing the beam of light onto the windshield so that it is reflected by it towards the eyes of the driver and thereby can see the virtual image at an appropriate size and distance beyond the windshield. However, the dimensions of the concave mirror scale linearly with the size of the virtual display area, which greatly limits it.As an alternative to this, therefore, for applications which require a significantly larger virtual display area, an HUD design with a large-area display which extends directly opposite the front screen in an upper side of the instrument panel is known. This is considered in particular for future fully automated or autonomously driving vehicles which are intended to manage without a vehicle-guiding user input, so that the associated entertainment systems in the occupant compartment are gaining in importance. For example, with an HUD of this type, it is desirable to superimpose additional information on the front window over its entire width in a situationally and depending on the external environment for a driver and / or a passenger of the vehicle and, if necessary, also to present a continuous panoramic virtual image. For this purpose, the image-forming display would have to extend over the entire width of the front screen.In order to meet high intensity requirements imposed on the display light when reflected in the transparent region of the front screen on the bright light day, an LED display would be more suitable than a liquid crystal screen because high intensity losses in the liquid crystal layer are unavoidable. However, for such a large display area, an excessively large number of LEDs (a few million) would be necessary, which in turn would have a significant impact on the energy balance and associated greenhouse gas output of the vehicle. Thus, a possible display size for a panoramic display is 1200 mm (length) by 300 mm (width) for a 4:1 ratio. Using a conventional screen, a construction of approximately 2,000,000 LEDs would be necessary for this purpose. These are lined up in approximately 1920 columns over the width of the HUD display. This large amount of LEDs would produce a greenhouse gas output of greater than 1.2 CO2 äquivalenten.In the prior art, for example for design and toy articles or greeting cards, rotating display devices with a circular display surface that can be generated by rotation are known, as described for example in U.S. Pat. No. 9,190,028 B2 or EP 4 030 412 A1. Such a rotary display device includes a fixed motor to the motor shaft of which a rotating unit rotated by the motor is fixed. The rotating unit is formed as at least one rod-shaped arm arranged in the radial direction, wherein an LED strip is fastened in the longitudinal direction on the arm. Suitable rotary or position sensors are provided for synchronizing the LED control with the rotation of the arm. Depending on the embodiment, this display device can comprise, for example, a single radial arm, two individual radial arms at a distance of 180° or four individual radial arms at a distance of 90° from one another. Similarly, WO 2019 / 023489 A1 discloses an apparatus and method for displaying an image generated by emitting or reflecting light by rotating elements such as blades of a fan.Further, WO 99 / 35634 A1 discloses a rotating display assembly having a round, elongated oval or polygonal cross section and a plurality of display elements uniformly distributed on a moving belt forming a peripheral surface of the assembly. In order to realize a plurality of different emission directions, separating walls with mutually different slopes can be provided between the individual display elements. US 2004 / 0212572 A1 discloses a similar display arrangement, wherein here too a movable band is wound around one or more parallel axes of rotation which are arranged in the corners of a correspondingly polygonal cross section.Typically, modern vehicles include an air conditioner, wherein a blower disposed in the instrument panel is used to distribute the air into the passenger compartment. The air conditioner blower requires much space in the instrument panel, which forces packaging compromises with other instruments and devices that must also be housed in the instrument panel.It is the object of the present invention to specify an alternative construction concept for a visual field display device which is improved with regard to the energy balance, the required installation space and / or economics and which also makes it possible to generate a large-area virtual image, for example for panoramic display. In particular, this visual field display device is to be suitable for integration in a vehicle and for virtual display via reflection on its front screen.This object is achieved by a projection unit according to claim 1 and a visual field display device containing the same and a vehicle equipped therewith according to the subordinate claims. Further embodiments are given in the dependent claims. All further features and effects mentioned in the claims and the following description for the projection unit also apply with respect to the visual field display device and the vehicle, as well as vice versa.According to a first aspect, a projection unit for a visual field display device is provided, which can be designed in particular for use in a vehicle. The visual field display device is designed to superimpose a virtual image in the visual field of a user via reflection on a reflective pane arranged in its visual field, in particular a vehicle pane. It can be designed, for example, as a head-up display (HUD).The projection unit is designed to generate a projection light beam ("projection light" for short) with a desired display content during operation of the visual field display device and to cast it onto the said reflection disk, whereby the desired virtual image appears to the user to be floating beyond the reflection disk. The user can be, in particular, a driver and / or passenger, but also other occupants of the vehicle.For this purpose, the projection unit comprises an imaging display surface which can be designed in particular for arrangement in or under an upper side of an instrument panel or a parcel shelf of the vehicle. The display surface is composed of a plurality of rectangular individual regions and is designed according to a conveyor belt concept in order to save the material and energy resources, in that each rectangular individual region comprises an associated mechanically movable belt (also referred to herein as "conveyor belt") with at least one light source strip fastened thereon, which extends transversely to the belt movement direction and carries light sources, for example LEDs, which are arranged one next to the other in their extension direction.During operation, the light source strips are moved through the respective strip as on a conveyor belt and thereby cover the associated rectangular individual region of the display surface. The respective light source strip can have, for example, a length (or width) of the individual region and can be moved back and forth over its entire width (or length) by means of the belt movement so quickly or "rotated" in a constant belt movement direction that it is time-insolubilized for the human eye. To generate a desired display content in the display area, the light sources can be controlled synchronously with the belt movement and independently of one another.The rectangular individual regions can be identical to one another or can be designed differently in terms of their shape and / or size and / or equipment, for example in order to optimally meet requirements for the display properties or the installation space that vary along the display surface.One concept of this projection unit consists, on the one hand, in the case of a visual field display device, such as, for example, an HUD, which can be designed for use in a vehicle, in replacing a large-area image-forming display surface with high luminous intensity, as is required, for example, for a panoramic-type virtual representation or for AR applications (augmented reality) in the front screen of the vehicle, by a conveyor-belt-type display surface which is known as such only from other applications. As a result, the number of LEDs required in the HUD display surface can be significantly reduced in such a way that, despite the added rotary drive consumption for the conveyor belt, a considerable improvement in the energy balance and thus also a reduction in the greenhouse gas output of the vehicle and-if the vehicle comprises a battery-electric drive-a correspondingly longer range can be achieved.A further idea is to divide 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 above-mentioned type, the conveyor belt would have to operate at a very high travel speed, particularly if it is a panoramic display. By dividing the required display area into several individual areas, each with its own conveyor belt, many new possibilities are obtained both from a geometric point of view and for the control. Thus, by using a plurality of smaller individual regions, the rotational speed of the respective conveyor belts can be significantly reduced. In addition, entire individual regions can be switched on and off as required during operation for energy saving or can be selectively adapted in their display properties. In addition, such a display area is easily scalable by the addition of further rectangular individual regions and can be flexibly adapted to geometric requirements of different applications by its modular construction.According to one embodiment, the projection unit comprises, for each rectangular individual region, two parallel axes of rotation of the strip, which extend on its opposite edges, i.e. rectangular sides, and a rotary drive which is designed to rotate at least one of the two axes of rotation of the strip. The band thereby forms a loop which is spanned between the two band axes of rotation and wound around the latter, wherein the at least one band axis of rotation rotatable by the rotary drive is configured for carrying along the band for generating the mentioned band movement. This can be, for example, a belt conveyor belt. The light source strips can extend, for example, parallel to the axes of rotation.As already mentioned, the lengths and alignments of the individual light source strips can correspond in particular 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 can be arranged in such a way that the bands and light source strips of the adjacent individual regions are aligned and movable parallel to one another. In this case, the individual regions merging into one another can also share, for example, axes of rotation of the strip, as a result of which the number of required rotary drives is reduced and a synchronous movement of the individual strips is always produced. This may be particularly useful for creating a coherent panoramic representation. If, on the other hand, the individual regions are used for content and display types that are independent of one another or for different users (for example, drivers and passengers or a plurality of users seated next to one another), they can also be configured and arranged independently of one another.Furthermore, the projection unit can optionally comprise a cover plate which extends along the imaging display surface in the beam path of the projection light emanating therefrom and is designed to transmit the projection light substantially loss-free and in the process at least partially close and protect the projection unit towards the outside. The cover pane can serve, among other things, to prevent a vehicle occupant from engaging moving elements of the display surface, and optionally be equipped with further mechanical and / or optical functions. It can be made of any suitable material, for example glass or transparent plastic such as acrylic glass, etc.According to one embodiment, the belt has a plurality of slats arranged on the outside, that is to say on the same side with the light source slats, which slats can be distributed uniformly, for example, along the belt movement direction. The lamellae extend parallel to one another and to the light source strips and are designed for imparting a predetermined emission direction to the projection light generated by the light source strips and / or for shielding the display surface in other directions. For this purpose, the slats can be spatially oriented substantially parallel to one another, in particular in the entire display surface. They can be designed to be light-absorbing or coated, for example, in order to block light beams in directions other than the desired emission direction.In a specific development of this embodiment, the individual movable belts are designed as cross-flow fans with ventilation slots running parallel to the blades and are therefore designed for simultaneous use as a fan and / or blower of an air conditioning system during operation of the projection unit. In this case, suitable air intake, air guide and / or air outflow openings and surfaces can be formed in the interior of the projection unit and / or in the housing or cover plate thereof, said openings and surfaces being designed for conducting and optionally distributing the air into predetermined air ducts. The individual air ducts can be designed, for example, for cooling 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.If the slats are designed, as described above, to provide visual protection for the light source strips, an additional cover pane and / or an adaptation of the geometry between the display surface in the upper side of the instrument panel and the gaze of the driver can be dispensed with. In this case, the slats extend approximately parallel to the reflective pane, so that this arrangement of the slats and the belt movement can at the same time also be used best for the above air conditioning concept and in particular for pane heating and defrosting.According to a further aspect, the abovementioned visual field display device is provided, which, in addition to a projection unit presented herein, also comprises a reflection pane mentioned further above, which can be formed, for example, by a vehicle pane or can be formed as an extra-provided combiner pane. The reflection plate is arranged in the beam path of the projection light output by the projection unit. It is reflective on the user side and can be at least partially transparent for the ambient light incident on the rear side, in particular, so that the virtual image is superimposed on the real environment observed by the user through the reflective pane. The reflective pane is arranged and designed in the field of view of the user in such a way that it reflects the projection light to an eyebox predetermined for user eyes and the display content can thereby be presented to him in the form of a virtual image beyond the reflective pane.In the embodiment described above, the slats can extend in particular approximately parallel to the reflective pane and, when installed in a vehicle, for example to the front pane thereof, in order to conceal the users or occupants from view of the light source strips and to emit the projection light only in the required direction toward the reflective pane.According to a further aspect, the above vehicle is provided, which can be, for example, a motor vehicle or any other land, air or watercraft. It has an occupant compartment and a vehicle window which delimits it at least partially outwards. The vehicle window may be, for example, a front window with an instrument panel arranged underneath or a rear window with a rear parcel shelf arranged underneath. Unless otherwise indicated, all spatial orientation terms used herein, such as "horizontal", "vertical", "above", "below", "below", "front", "rear", "left", "right", etc., refer to the usual vehicle-fixed Cartesian coordinate system with longitudinal, transverse and height directions of the vehicle perpendicular to one another. The vehicle further comprises the above visual field display device, the projection unit of which is arranged in the passenger compartment, in particular in or under an upper side of the instrument panel or rear parcel shelf, and the reflective pane of which is formed as part of the vehicle pane or as a combiner pane arranged separately in the passenger compartment.In particular, the front window in the vehicle transverse direction toward the left and toward the right can each be bounded 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 front window serves as a reflection pane of the visual field display device at least with a major part of its extent in the vehicle transverse direction. In this way, in particular a panoramic virtual representation for the driver and / or passenger can be realized. For this purpose, in particular a plurality of rectangular individual regions of the type presented herein can be arranged next to one another in the transverse direction of the vehicle.The above aspects of the invention and its embodiments and specific embodiments will be described below with reference to examples illustrated in the accompanying drawings. The drawings are purely schematic and therefore should not be understood as true to scale. The following are shown: FIG. 1 shows a detail of a vehicle with a visual field display device according to an exemplary embodiment of the invention in a vertical longitudinal section; FIG. 2 shows a plan view of an imaging display surface composed of three individual regions of the visual field display device of FIG. 1 ; FIG. 3 a shows a cross-sectional view of one of the three individual regions of the imaging display surface of FIG. 2 ; and FIG. 3 bshows the individual region of FIG. 3 ain plan view.All the various embodiments, variants and specific design features of the projection unit, the visual field 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 examples shown in FIGS. 1 to 3 b, in particular also alternatively or additionally to the features shown therein. They are therefore not all repeated again below. The same applies correspondingly to the term definitions and effects already given above with respect to individual features shown in FIGS. 1-3 b.FIG. 1 shows a greatly simplified schematic illustration in a vertical longitudinal section of a section of a vehicle 1 with a visual field display device 2 according to an exemplary embodiment of the invention. The visual field display device 2 is here embodied purely by way of example as a head-up display (HUD).The visual field display device 2 serves for generating a virtual image V in the visual field of a user, for example a driver of the vehicle 1, which is indicated in the vertical longitudinal sectional view of FIG. 1 only by his eyes 3 and an eyebox E intended for this purpose in the passenger compartment of the vehicle 1. (As usual, the eyebox is understood herein to mean a spatial region intended for the eyes of a user of the visual field display device 2, from which region he can see the virtual image V in the intended presentation quality.) The vehicle 1 is a motor vehicle purely by way of example. It is indicated in FIG. 1 solely by its front pane 4, an instrument panel 5 extending underneath it and not shown in more detail, and a roof lining 6 extending above it.The head-up display device 2 comprises a projection unit 7 which, in this example, is arranged below the front window 4 in the instrument panel 5. The projection unit 7 is configured and arranged to generate and output a projection light beam L (hereinafter referred to as "projection light" for short) with respectively desired display content in the direction of the front windshield 4 so as to be reflected from the front windshield 4 to the user eyebox E and thereby allow the user to see the virtual image V when looking into the front windshield 4.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 is illustrated in more detail in FIGS. 2 and 3 a- 3 b. The projection light L is indicated in FIG. 1 solely by its central beam which leads from a center of the imaging display surface 8 into a center of the eyebox E. The projection unit 7 can optionally additionally comprise a cover pane 11 which at least partially covers and protects the display surface 8 toward the front pane 4 and in this case allows the projection light L emanating therefrom to pass through largely loss-free.As shown in FIG. 2 in a plan view of the display surface 8 of FIG. 1, the desired display region is divided into a plurality of individual regions 8 a, 8 band 8 c, here purely by way of example three. Each of these individual regions 8 a- 8 cis assigned a mechanically moved belt (conveyor belt) 10, for example a belt conveyor belt, which moves at least one light source strip (here LED strip) 9 aligned orthogonally to its belt movement direction R. By dividing the imaging display surface 8 into three individual regions 8 a- 8 c, for example, the possibility is provided for the separate display of contents for the driver (left, individual region 8 a), the passenger (right, individual region 8 c) and on a common region (center, individual region 8 b). The belt movement direction R is oriented approximately in the vehicle longitudinal direction in this example, wherein depending on the application other alignments and arrangements of the individual regions 8 a- 8 crelative to one another are also possible. For example, the belt movement direction R of the respective conveyor belt 10 can also be oriented in the vehicle transverse direction, with a corresponding orientation of the light source strips 9.FIGS. 3 a- 3 b show in a cross-sectional view (FIG. 3 a ) and a plan view (FIG. 3 b ) in a greatly simplified manner a basic structure of the individual region 8 aof the imaging display surface 8 of FIG. 2 ; in this example, the two other individual regions 8 band 8 care configured similarly or identically thereto.As can be seen in FIG. 3 a, the individual region 8 aincludes a conveyor belt 10 equipped with slats 14 which carries along a plurality of 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 be distributed in particular uniformly along the belt 10. As shown in the top view of FIG. 3 b, in this example, at any point in time typically two to three light source strips 9 are located in the individual region 8 aof 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 region 8 ameasured in the vehicle transverse direction, are moved rapidly back and forth over the entire length of the desired display region measured in the vehicle longitudinal direction and / or are always rotated in the same belt movement direction R. Each strip 9 carries light sources (not shown separately) arranged in a row in its longitudinal direction, in this example LEDs, which can be controlled independently of one another and synchronously with the tape movement for the purpose of generating images in the imaging display surface 8.In order to generate this conveyor belt movement, the projection unit 7 comprises in the individual region 8 atwo parallel belt axes of rotation 12 which extend on two opposite edge sides of its rectangular surface, and a rotary drive (not shown) which is designed to rotate at least one of the two belt axes of rotation 12. As can best be seen in the cross-sectional view of FIG. 3 a, the band 10 forms a loop which is clamped between the two axes of rotation 12 of the band and is wound around the latter. In this example, both axes of rotation 12 of the belt have gear-like projections for entrainment of the belt 10 during its rotation, wherein the belt 10 has, on its inner surface facing the axes of rotation 12, projections of complementary design, which engage positively between the gear-like projections of the axes of rotation 12.In this example, the conveyor belts 10 are designed as cross-flow fans with blades 14 arranged on their outer sides. In this way, the flow belts 10 additionally serve as a blower of an air conditioning system for heating or defrosting the front pane 4 and / or for cooling the projection unit 7. the slats 14 can run, for example, parallel to the light source slats 9 and be distributed uniformly along the belt movement direction R, as illustrated in FIG. 3 a.In this case, all of the slats 14 in the display surface 8 are oriented spatially identically to one another in order to emit projection light L (cf. FIG. 1 ) in a predetermined emission direction toward the front window 4 and to 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 visual field display device 2 via reflection in the front pane 4 is visible to the occupants.Depending on the desired maximum displayable frame rate, the number of individual regions 8 a- 8 cand the respective light source strips 9 carried along per conveyor belt 10 can also be chosen differently than in this example.List of reference characters1 Vehicle 2 Visual field display device 3 Eye of the user 4 Front screen 5 Instrument panel 6 Roof lining 7 Projection unit 8 Imaging display surface 8 a, 8 b, 8 c Einzel regions of the display surface 9 Light source strip, in particular LED strip 10, moved strip, also referred to as conveyor strip 11 Cover screen 12 Strip rotational axis 14 Strip E Eyebox of the user L Projection light (beam bundle of rays) R Strip movement direction V Virtual image

Claims

Projection unit (7) for a visual field display device (2) which is designed for the insertion of a virtual image (V) by reflection on a reflective pane arranged in the visual field of a user, in particular a vehicle pane (4), comprising: - an imaging display area (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 a plurality of rectangular individual regions (8a, 8b, 8c); wherein - each of these individual regions (8a, 8b, 8c) is formed by an associated mechanically movable belt (10) with at least one light source strip (9) fastened thereon, which extends transversely to its belt movement direction (R) and carries light sources arranged in a row in its extension direction, 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).Projection unit (7) according to claim 1, - further comprising, for each rectangular individual region (8a, 8b, 8c), two parallel axes of rotation of the strip (12), which extend on the opposite rectangular sides thereof, and a rotary drive, which is configured to rotate at least one of the two axes of rotation of the strip (12); - wherein the strip (10) forms a loop, which is spanned between the two axes of rotation of the strip (12) and is wound around the latter, wherein the at least one axis of rotation of the strip (12), which is rotatable by the rotary drive, is configured to carry along the strip (10) in order to generate said strip movement.Projection unit (7) according to Claim 1 or 2, wherein - lengths and alignments of the light source strips (9) correspond to a length or a width of the respective rectangular individual region (8a, 8b, 8c).Projection unit (7) according to one of the preceding claims, wherein - the rectangular individual regions (8a, 8b, 8c) in the composite display area (8) adjoin one another along their respective lengths and / or widths and are arranged in such a way that their associated belts (10) and light source strips (9) are aligned and movable parallel to one another.Projection unit (7) according to one of the preceding claims, wherein - the belt (10) has a plurality of lamellae (14) which are arranged on the outside and are preferably distributed uniformly along the belt movement direction (R) and extend parallel to one another and to the light source strips (9) and are designed for imparting a predetermined emission direction to the projection light (L) generated by the light source strips (9) and / or for shielding the display surface (8).Projection unit (7) according to Claim 5, wherein - the slats (14) are spatially aligned substantially parallel to one another in the entire display area (8).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 therefore designed for simultaneous use as a fan and / or as a fan of an air-conditioning system during operation of the projection unit (7).A visual field 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 plate, such as a vehicle plate (4) or an extra-provided combiner plate, arranged in the beam path of the projection light (L) output by the projection unit (7); - wherein the reflection plate is arranged and designed in the visual field of the user in such a way that it reflects the projection light (L) to an eye box (E) predetermined for user eyes (3), whereby the display content can be displayed to him in the form of a virtual image (V) beyond the reflection plate.Vehicle (1) having mutually perpendicular longitudinal, transverse and height directions of a vehicle-mounted Cartesian coordinate system, in particular a motor vehicle, comprising: - an occupant compartment and a vehicle window which delimits it at least partially outwards, in particular a front window (4) with an instrument panel (5) arranged beneath it; and - a visual field display device (2) according to Claim 8, the projection unit (7) of which is arranged in the occupant compartment and the reflection window of which is formed as part of the vehicle window or as a combiner window arranged separately in the occupant compartment.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 front screen (4) serves, at least with a large part of its horizontal extent, as a reflection screen of the visual field display device (2).

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