DISPLAY DEVICE, HEAD-UP DISPLAY AND VEHICLE

Abstract

The present invention relates to a display device (50) for a head-up display (40), a head-up display (40) and a vehicle (100), wherein the display device (50) comprises a display display (52) with a display surface (57) and an optical refractive element (54).The optical refractive element (54) is arranged in the beam path of a light (10) emitted by the display (52) and is designed and arranged relative to the display (52) in such a way that the spatial orientation of an image information (10) to be projected is changed in a defined manner by an image information (10) displayed on the display (52) as a result of the passage of the associated emitted light (10) through the optical refractive element (54), wherein there is a space between the display surface (57) of the display (52) and the entrance surface (55) of the optical refractive element (54), which is at least partially filled with a filling material (53) made of a material that is at least partially transparent.

Description

[0001] The present invention relates to a display device for a head-up display, in particular for an AR head-up display, i.e., for an augmented reality head-up display, wherein the display device comprises a display with a display surface and at least one optical refractive element with a first refractive index. The at least one optical refractive element has an entrance surface and an exit surface and is arranged at least partially in the beam path of light emitted by the display, such that at least a portion of the light emitted by the display during operation of the display device passes through the optical refractive element.The optical refractive element is designed and arranged relative to the display, in particular to the display surface, in such a way that the spatial orientation of the projected image information is changed in a defined manner by the passage of the associated emitted light through the optical refractive element.

[0002] Furthermore, the present invention relates to a head-up display, in particular an AR head-up display, with a display device for displaying image information to be projected.

[0003] Furthermore, the present invention relates to a vehicle, in particular a motor vehicle, with a head-up display.

[0004] Head-up displays are a well-known technology, with various designs existing. Besides head-up displays that project a vertical image containing the displayed information into the driver's field of vision, so-called AR head-up displays (AR = Augmented Reality) are also known, which project the displayed information into the real world.

[0005] Some well-known AR head-up displays can project navigation instructions, such as directional arrows, directly onto the road, allowing drivers to see them without taking their eyes off the road. For projection onto the road, the image information to be projected, or the resulting projection plane onto which the image information is to be projected, must be tilted at a defined angle relative to a vertical plane. This can be achieved, for example, by tilting the display that outputs the projected image information, utilizing the "Scheimpflug condition." The "Scheimpflug condition," also known as the "Scheimpflug rule," is described, for example, here: https: / / de.wikipedia.org / wiki / Scheimpflugsche Regel, last accessed on April 30, 2023.

[0006] The required tilt of the display to achieve the desired angle of the projected image information or virtual image can vary depending on the vehicle type, the driver's seating position, and other factors. In many head-up display systems, the display is tilted by 10-15 degrees around a horizontal axis relative to a vertical plane to project a tilted virtual image. However, in some cases, greater tilts may be necessary to project the image information completely onto the road surface.

[0007] Head-up displays often use thin-film transistor (TFT) displays to project the image information. While these offer many advantages due to their high image quality and durability, they also have the disadvantage of a limited viewing angle. This means the screen can only be viewed from a limited area before the colors and contrast become distorted. If a TFT display is tilted too sharply, sufficient contrast can no longer be achieved, resulting in inadequate projection quality.

[0008] To solve this problem, US 11,175,500 B2 proposes to place a prism with a triangular cross-section in the beam path.

[0009] Against this background, it is an object of the present invention to provide an alternative display device, in particular an improved display device, for a head-up display, with which the projection of image information can be improved, wherein the image information can be projected, in particular, with a larger angle of inclination, i.e., with a larger projection plane inclination angle. Furthermore, it is an object of the present invention to provide an alternative head-up display, in particular an improved head-up display, and an alternative vehicle, in particular an improved vehicle, with each of which an improved projection of image information can be achieved.

[0010] This problem is solved according to the invention by a display device, a head-up display, and a vehicle with the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description, and the figures. The wording of the claims is made explicit by reference to the content of the description.

[0011] A display device according to the present invention can be configured, in particular, for a head-up display, especially for an AR head-up display, wherein the display device comprises at least one display with a display surface and at least one optical refractive element with a first refractive index. The at least one optical refractive element has an entrance surface and an exit surface and is arranged, at least partially, in the beam path of light emitted by the display, such that at least a portion of the light emitted by the display during operation of the display device passes through the optical refractive element.The optical refractive element is designed and arranged relative to the display, in particular to the display surface, in such a way that the spatial orientation of the image information to be projected is changed in a defined manner by the passage of the associated emitted light through the optical refractive element.

[0012] A display device according to the invention is characterized in that there is a space between the display surface of the display and the entrance surface of the optical refractive element, which is at least partially filled with a filling material made of a material that is at least partially transparent.

[0013] Because the filler material is at least partially transparent, light emitted from the display can pass through it. If the filler material has a defined refractive index, the spatial orientation of the projected image information can be influenced by the filler material, in addition to the influence of the optical refractive element, and in particular, advantageously modified. Thus, a suitable filler material in the space between the display surface and the optical refractive element can advantageously influence the spatial orientation of the projected image information.

[0014] By using an optical filler material, particularly a transparent filler material with a suitable refractive index, and a suitable geometric design of the space between the materials, or especially a suitable geometric design and orientation of the interfaces between the individual materials, the spatial orientation of the projected image information can be influenced particularly advantageously. With a suitably appropriate design, for example, an additional tilt of the projection plane, and thus of a virtual projected image, can be achieved with minimal effort, without having to increase the display tilt angle of the screen.

[0015] By filling the gap with a filler material of a defined refractive index, the negative effects that arise in an air-filled gap due to multiple refractions at the interfaces between the individual media can be significantly reduced or almost completely eliminated, especially if the refractive index of the filler material is appropriately chosen, for example, similar to the refractive index of the display surface and / or the optical refractive element. In particular, disruptive multiple reflections can be reduced or avoided. This allows for improved projection of the image information, especially larger projection plane tilt angles, while maintaining sufficient projection quality.

[0016] Filling the gap with filler material can also improve the mechanical and / or thermal properties of the display device. The resulting mechanical properties depend in particular on the chosen filler material, the size of the gap, especially the thickness of the filler layer, and whether the filler material is bonded to the display surface and / or the optical refractive element, for example, by a metallurgical bond. Through appropriate connections, especially metallurgical bonds between the filler material and the optical refractive element and / or between the filler material and the display, especially the display surface, the mechanical and / or thermal properties of the display device can be significantly improved, depending on the design of the (optional) connection(s).

[0017] A "head-up display (HUD)" within the meaning of the present invention is a display device, in particular an electronic display device, with which information, especially visual information in the form of an image, can be projected directly into the field of vision of a viewer. For example, with a head-up display in a vehicle, image information such as navigation information or speed information can be projected into the driver's field of vision, so that the driver can perceive this information without having to take their eyes off the surroundings.

[0018] An “AR Head-Up Display” within the meaning of the present invention is a special head-up display with which image information to be displayed can be projected into the real world, wherein the image information to be displayed can be projected not only into a vertical projection plane, but into at least one projection plane with a spatial orientation other than a vertical orientation, wherein the image information to be displayed can be projected, in particular, into a projection plane inclined by a defined projection plane inclination angle.

[0019] A “display device” within the meaning of the present invention is understood in particular to be a device which can visually output information by means of a display display.

[0020] A display device according to the present invention, in particular the display display, can in particular be connected to an image generation device via communication, signal and / or energy, or may include an image generation device, wherein the image generation device can in particular be configured to generate image information to be projected, which can be displayed or visually output by means of the display device, in particular by means of the display display.

[0021] A display device according to the present invention can be adapted and designed in particular for use in a head-up display comprising a combiner, wherein in this case the image information displayed by the display device can preferably be projected onto a combiner by means of one or more reflection devices.

[0022] Alternatively or additionally, the display device can also be adapted and designed for use in a windshield head-up display, in which case the image information displayed by the display device can be projected onto the windshield, in particular by means of one or more reflective devices.

[0023] Both types of head-up displays, head-up displays with combiner and windshield head-up displays, are fundamentally known from the prior art, to which reference is hereby made for further details on general design and / or functional aspects of such head-up displays.

[0024] A “display” within the meaning of the present invention is in particular an electronic display device that can display visual information such as text, graphics, images and / or videos, especially as an image.

[0025] The display can be specifically designed to display or output information such as one or more navigation information, vehicle speed information, or any other information that might be of particular interest to a driver of a vehicle, as image information.

[0026] The display surface of the display can, in particular, be a flat surface, at least partially or completely, which can extend in a display plane.

[0027] The display surface of the display device, in particular the display screen, is preferably rectangular. However, other geometric configurations are also possible, such as a square or circular display surface, a combination thereof, or a configuration that cannot be described by simple geometric shapes. A rectangular display surface has proven particularly advantageous for a head-up display intended for use in a vehicle, as the visual information to be displayed to the driver can be presented clearly and concisely on such a surface, and a display screen with this configuration can generally be easily integrated into the installation space provided for a head-up display in the vehicle.

[0028] A display device according to the present invention can in particular be designed to be installed in a head-up display or a vehicle, especially in the case of a rectangular display surface, in landscape format.

[0029] For the purposes of the present invention, an "optical refractive element" is understood to be, in particular, a component or an assembly composed of several individual components, which is designed to influence transmitted light by refraction, especially the direction of the light rays. Depending on the design of the optical refractive element, the spatial orientation of the image information to be projected, which is represented in particular by at least a portion of the light rays emitted by the display, can be selectively and precisely altered by the optical refractive element.

[0030] The optical refractive element can be made of one or more materials. It can have various geometric configurations and be arranged with different orientations relative to the display, particularly its surface. The specific geometric configuration and orientation are preferably determined by the application. In particular, the geometry and orientation of the entrance surface, exit surface, and / or—if present—one or more interfaces within the optical refractive element can be adapted to the specific application and, in particular, to the desired projection result.In particular, the geometry and orientation of the entrance surface, exit surface and / or - if present - one or more interfaces inside the optical refractive element can be designed in such a way that an additional inclination of the projection plane can be caused, i.e., the angle of inclination of the projection plane can be increased by the optical refractive element.

[0031] The optical refractive element is, in particular, at least partially transparent, preferably completely transparent (i.e., transparent over its entire extent), and especially transparent to at least visible light (i.e., light with a wavelength in the visible range of approximately 380 nm to 800 nm). This ensures good transmission of the light emitted by the display. However, for certain applications, it may be advantageous for the optical refractive element to be transparent to other wavelength ranges.

[0032] The optical refractive element can be made of, or consist of, glass, plastic, or crystal. Preferably, the optical refractive element is made of a material that has a refractive index similar to that of glass, i.e., a refractive index of approximately 1.5. This allows for particularly advantageous control of the direction of the light emitted by the display.

[0033] The optical refractive element can, in particular, be a three-dimensional refractive body, i.e., a 3D refractive element. The optical refractive element can, in particular, be designed and arranged relative to the display such that light emitted from the display can enter the optical refractive element via the entrance surface, pass through it, and exit again via the exit surface. Preferably, the light emitted from the display can be refracted at the entrance surface and / or the exit surface. With a suitable refractive index, this can achieve an advantageous influence on the light emitted by the display.

[0034] The inlet surface and / or the outlet surface can each be a flat surface. This allows for a particularly simple and advantageous design of the optical refractive element. However, the inlet surface and / or the outlet surface can also be at least partially curved if this results in a more advantageous outcome for a desired projection, in particular a more advantageous influence on the spatial orientation of the light rays emitted by the display device.

[0035] In a particularly advantageous embodiment of a display device according to the present invention, the optical refractive element is configured to influence the light rays emitted by the display in such a defined manner that the inclination of a resulting projection plane about a horizontal axis, into which a virtual image can be projected with the aid of the display device, is or can be changed, in particular increased.

[0036] In an advantageous embodiment of a display device according to the present invention, the optical refractive element is specifically designed to influence the light rays emitted by the display such that the tilt angle of a virtual image, i.e., a projected image, is increased by at least 1 degree, 2 degrees, 3 degrees, 5 degrees, 7 degrees, 8 degrees, 10 degrees, 12 degrees, 15 degrees, 20 degrees, or 25 degrees. This allows the tilt angle of a virtual image, or the tilt angle of a projection plane of a head-up display (into which the virtual image can be projected by the head-up display), to be increased in a simple manner without increasing the display tilt angle of the display itself. This reduces or eliminates negative effects, such as a deterioration in contrast, which can occur particularly with excessively large display tilt angles of TFT displays.be avoided.

[0037] For the purposes of the present invention, an “intermediate space” is understood to be an area, in particular a volume, between the display surface of the display and the optical refractive element, in particular its entrance surface.

[0038] For the purposes of the present invention, a "filling material" is understood in particular to be a material that is suitable for filling a volume, such as an interstitial space.

[0039] The filler material is, in particular, at least partially transparent, preferably completely transparent (i.e., transparent across its entire extent), and especially transparent to at least visible light (i.e., light with a wavelength in the visible range of approximately 380 nm to 800 nm). This ensures good transmission of the light emitted by the display. However, for certain applications, it may be advantageous for the filler material to be transparent to other wavelength ranges.

[0040] The filling material can, in particular, comprise or consist of an optical plastic and / or an optical adhesive. Preferably, the optical refractive element is made of a material having a refractive index similar to that of glass, i.e., a refractive index of approximately 1.5. Filling the cavity with such a material, especially compared to an air-filled cavity, allows for improved control of the direction of the light rays emitted by the display, particularly at larger projection plane tilt angles.

[0041] The filling material may, in particular, contain or consist of one of the following plastics or a combination thereof: polymethyl methacrylate (PMMA or acrylic glass), polycarbonate (PC), cycloolefin copolymer (COC), styrene acrylonitrile (SAN).

[0042] The filler material may also contain an optical adhesive, or a combination of optical adhesives, such as an optical epoxy adhesive, an optical silicone adhesive, an optical acrylate adhesive, and / or an optical cyanoacrylate adhesive. Furthermore, other suitable optical adhesives are available and can be selected according to the requirements of the specific application.

[0043] The filler material can, in particular, completely fill a three-dimensional gap between the optical refractive element, especially its entrance surface, and the display surface. In this case, the filler material forms a three-dimensional refractive body. The filler material can, in particular, fill the gap in such a way that light emitted from the display enters the filler material directly from the display surface. Furthermore, the filler material can, in particular, fill the gap in such a way that it extends directly to the optical refractive element, especially to its entrance surface, so that light entering the filler material passes directly into the optical refractive element upon exiting the filler material. This can reduce or eliminate unwanted multiple refractions and / or multiple reflections in the beam path.This can be avoided, which has a positive effect on the projection quality.

[0044] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the display is in particular a TFT display (Thin Film Transistor Display), especially an LCD display, a µLED display, or an OLED display. Alternatively, the use of a so-called "Digital Micromirror Device (DMD)" would also be possible. The display can be configured to be arranged at a defined tilt angle relative to a principal optical plane, in particular relative to a vertical principal optical plane with respect to a functional operating state of the display device, especially in a head-up display and / or in a vehicle.

[0045] TFT displays are relatively inexpensive and available in a wide variety of designs, especially in various sizes, and offer high image quality. The abbreviation "LCD" stands for "Liquid Crystal Display." An LCD display has a layer of liquid crystals sandwiched between two polarized glass plates. When an electrical voltage is applied to the display, the molecules of the liquid crystals change, affecting the transmission of light. This creates an image on the display. The abbreviation "OLED" stands for "Organic Light Emitting Diode." An OLED display consists of organic materials that emit light when an electric current flows through them. Unlike LCD displays, OLED displays do not require backlighting, as each pixel in an OLED display is self-illuminating.OLED displays offer many advantages over LCD displays, such as higher contrast, faster response times, and better viewing angles. OLED displays can also be manufactured very thin and flexible.

[0046] In an advantageous embodiment of a display device according to the present invention, the display is designed to be installed at an angle or arranged at an angle, in particular inclined about a horizontal axis, relative to a functional state of use, for example in a vehicle. A display device according to the present invention can, in particular, be designed such that the display can be fixedly installed with a defined display tilt angle, and / or such that a display tilt angle relative to a vertical plane (relative to a functional installation or state of use) is changeable, in particular pivotable as required, preferably adjustable in a defined manner, for example by means of an electric motor as an actuator.

[0047] With a tilting display, image information or virtual images can be projected not only onto a vertical plane, but also at an angle or onto a projection plane tilted by a defined angle. Depending on the angle of inclination, image information can thus be projected into the real world, as perceived, for example, by the driver of a vehicle.

[0048] For example, orientation arrows for navigation can be projected onto the roadway or into a projection plane that coincides with a roadway plane using a display that is sufficiently inclined about a horizontal axis relative to a vertical plane.

[0049] Furthermore, if the display tilt angle of the display can be variably adjusted, especially as required and particularly around a horizontal axis, image information with different tilt angles can be projected into the real world, thereby achieving a particularly realistic and advantageous presentation of the information to be displayed.

[0050] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the defined display tilt angle is preferably 0 degrees to 45 degrees, preferably more than 0 degrees, but particularly preferably not more than 40 degrees, and most preferably not more than 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, or 5 degrees. With such display tilt angles, particularly advantageous projection results can be achieved, especially particularly advantageous projection results for displaying image information to a vehicle driver.

[0051] In a possible, particularly advantageous embodiment of a display device according to the present invention, the optical refractive element is particularly designed to change the angle of inclination of the projected image information, i.e., the virtual image, in a defined manner in a head-up display, in particular to increase an inclination.

[0052] In a particularly advantageous embodiment of a display device according to the present invention, the display device is in particular configured such that a desired tilt angle of a projected / virtual image of more than 20 degrees, 30 degrees, 35 or 40 degrees can be achieved with the aid of the display device, wherein the display tilt angle is preferably smaller than the tilt angle of the projected / virtual image, in particular by at least 5 degrees, 7 degrees, or 10 degrees or more.

[0053] In one possible, and particularly advantageous, embodiment of a display device according to the present invention, the optical refractive element is at least partially wedge-shaped, in particular as a wedge plate. Such an optical refractive element allows for a particularly simple increase in the tilt angle of a projected / virtual image.

[0054] In a particularly advantageous embodiment of a display device according to the present invention, the optical refractive element, in particular the wedge plate, is designed such that image information displayed and projected by means of the display is tilted by the optical refractive element by an additional angle of inclination, wherein a resulting (total) projection plane tilt angle is in particular greater than the display tilt angle, in particular by at least 1 degree, 2 degrees, 3 degrees, 5 degrees, 7 degrees, 8 degrees, 10 degrees, 12 degrees, 15 degrees, 20 degrees or 25 degrees.

[0055] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the exit surface of the optical refractive element has, in particular, a planar surface, wherein the planar surface defines, in particular, an exit plane, and the optical refractive element is preferably arranged relative to the display, in particular to its display surface, such that the exit plane is oriented parallel to the display surface. This allows for a particularly advantageous display device with which a particularly advantageous influence on the light rays emitted by the display can be achieved.

[0056] In particular, the inlet surface and the outlet surface can each have or be a flat surface and thus, in particular, have or be an inlet plane and an outlet plane, wherein the flat surfaces of the inlet surface and the outlet surface, in particular the inlet plane and the outlet plane, are preferably inclined relative to each other by a defined angle, in particular by a horizontal axis.

[0057] The entrance and exit surfaces of the optical refractive element can extend, in particular, in a transverse direction of the display and be inclined relative to each other about an axis in this transverse direction. The optical refractive element can, in particular, be a prism, for example, a prism with a triangular or trapezoidal cross-section.

[0058] The optical refractive element can extend in a region in front of the display surface, in particular such that all light rays emitted by the display enter the optical refractive element via the entrance surface, pass through the optical refractive element, and exit the optical refractive element via the exit surface. Alternatively, the optical refractive element can extend only over a partial region in front of the display surface, so that only a portion of the light rays emitted by the display enter the optical refractive element via the entrance surface.

[0059] The optical refractive element can have a constant refractive index across its entire extent, or it can have two or more areas with different refractive indices. Such a design of the optical refractive element allows, for example, different viewing angles of a virtual image to be created. This makes it easy to implement, for instance, so-called split-screen displays with different viewing angles of the virtual images in different areas of the field of view.

[0060] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the optical refractive element, especially when designed as a wedge plate, has a constant geometric cross-section in the width direction, particularly in the horizontal direction, of the display, with respect to a functional operating state of the display, particularly with respect to a functional installation state in a vehicle as part of a head-up display. This allows the use of a geometrically very simple optical refractive element.

[0061] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the wedge-shaped optical refractive element tapers from an upper edge of the display to a lower edge of the display, or vice versa, depending on the desired change in orientation. By tapering the wedge-shaped optical refractive element from an upper edge of the display to a lower edge of the display, an increase in the tilt angle of the projection plane can be achieved in a simple manner.

[0062] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the optical refractive element has, at least in certain areas, and in particular the entire optical refractive element, a refractive index of 1.0 to 2.0, and in particular a refractive index greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, and in particular less than 2.0, 1.9, 1.8, 1.7, or 1.6. A refractive index for the optical refractive element of approximately 1.3 to 1.6, and in particular 1.5, has proven to be particularly advantageous. This allows for particularly advantageous projection plane inclination angles to be achieved with a head-up display for a vehicle, in particular for a motor vehicle.

[0063] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the filler material preferably has a second refractive index, wherein the refractive index of the filler material is particularly greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and particularly less than 2.0, 1.9, 1.8, 1.7, or 1.6. A refractive index for the filler material of approximately 1.3–1.6, and in particular 1.5, has proven to be particularly advantageous. This allows for particularly advantageous projection plane inclination angles to be achieved with a head-up display for a vehicle, especially for a motor vehicle. With such a refractive index of the filler material, which is essentially similar to the refractive index of an ordinary display glass, refraction that is unfavorable for an inclination angle during the transition of the light rays from the display glass into the environment (air) can be avoided, or the resulting negative effects can be reduced.

[0064] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the second refractive index is equal to the first refractive index and / or equal to a refractive index of the display surface, or does not deviate by more than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% from the first refractive index or the refractive index of the display surface. This allows for a particularly advantageous refraction of the light rays emitted by the display with respect to a large tilt angle of the projection plane.

[0065] In a possible, and particularly advantageous, embodiment of a display device according to the present invention, the optical refractive element is at least partially bonded to the display surface over a planar area, in particular by means of a material bond, preferably by means of the filler material. This allows for a good bond between the optical refractive element and the display surface, which, due to the resulting larger display mass, has a particularly advantageous effect on the mechanical and / or thermal properties, and, with a suitably selected filler material, especially without adverse optical effects.

[0066] In this case, the filler material is preferably chosen, particularly with regard to its thermal properties, in such a way that thermal stresses are largely avoided, whereby in particular a filler material can be selected which has a similar coefficient of thermal expansion as the optical refractive element and / or the display surface.

[0067] Preferably, the optical refractive element is fully bonded to the display surface by means of the filler material, particularly by a material-bonded connection. A particularly advantageous and simple material-bonded connection can be achieved, for example, by means of an optical adhesive, i.e., a translucent adhesive which also has, in particular, a defined refractive index that is advantageous for the desired purpose.

[0068] Instead of using an adhesive, the planar connection between the optical refractive element and the display surface can also be created by injecting a suitably appropriate optical plastic into the gap.

[0069] A head-up display according to the present invention comprises a display device for displaying projected image information and is characterized in that the display device is a display device designed according to the present invention. A head-up display according to the present invention can, in particular, be an AR head-up display.

[0070] Head-up displays, also known as AR head-up displays, are generally known from the prior art, to which reference is hereby made for further details regarding general design and / or functional aspects of a head-up display according to the present invention.

[0071] A head-up display according to the present invention and / or its display device may in particular include an image generation device for generating the image information to be projected.

[0072] To correct image errors that may occur, in particular to correct chromatic aberration, which may be caused in particular by the optical refractive element, the head-up display and / or the display device may further have a corresponding correction device, which is designed in particular to reduce and / or compensate for image errors such as chromatic aberration.

[0073] Furthermore, the head-up display can have one or more reflective devices in the form of flat or curved mirrors, in particular a flat mirror and a concave curved mirror, which can be arranged one behind the other in the beam path. In a particularly advantageous embodiment of a head-up display according to the present invention, one or more of the reflective devices or mirrors can be adjusted, in particular with respect to their inclination, in order to enable a driver of a vehicle, in particular a motor vehicle, to have a good view of the image depending on the seating position or depending on the driver's size, and to project the image information into the driver's field of vision, in particular the driver's eyebox.

[0074] In one possible, and in particular an advantageous, embodiment of a head-up display according to the present invention, the head-up display is configured such that, in a functional installation state of the head-up display in a vehicle, the display is or can be arranged inclined at a defined display tilt angle relative to a principal optical plane, in particular relative to a vertical principal optical plane with respect to a functional installation state of the head-up display in a vehicle, wherein the defined display tilt angle is 0 degrees to 45 degrees, preferably more than 0 degrees, but in particular not more than 40 degrees, and most preferably not more than 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, or 5 degrees. This allows a defined tilt of the projection plane, and thus a projection of the image information at a defined tilt angle, to be achieved due to the Scheimpflug condition.

[0075] The smaller the display tilt angle, the greater the achievable projection quality, especially with a TFT display as the display screen.

[0076] In a further possible, and particularly advantageous, embodiment of a head-up display according to the present invention, the head-up display is configured, in particular, to project image information inclined at a defined projection plane inclination angle relative to a principal optical plane, or to generate a corresponding virtual image inclined at a defined projection plane inclination angle relative to a principal optical plane, in particular relative to a vertical principal optical plane with respect to a functional installation state of the head-up display in a vehicle, wherein the projection plane inclination angle is greater than the projection plane inclination angle achievable with a given display inclination angle according to the Scheimpflug condition, in particular by an additional inclination angle of at least 1 degree, 2 degrees, 3 degrees, 5 degrees, 7 degrees, 8 degrees, 10 degrees, 12 degrees, 15 degrees, 20 degrees or 25 degrees.This allows for a particularly advantageous projection of image information, for example, a projection of image information onto the road surface, especially with a display tilt angle at which sufficient contrast is still achieved even with a TFT display.

[0077] A vehicle according to the present invention has a head-up display according to the invention.

[0078] Such a vehicle can be, in particular, a two-track vehicle, such as a passenger car, a truck, a van, a motorhome, or any other type of road vehicle. Such a vehicle can also be a single-track vehicle, such as a motorcycle, a scooter, or the like. Such a vehicle can also be any other type of motorcycle. Such a vehicle can have any type of propulsion (internal combustion engine, electric motor, hydrogen propulsion, fuel cell, etc.). Such a vehicle can also be an aircraft or a watercraft, such as a civil or military aircraft or a ship, in which case the head-up display is specifically designed to project a virtual image.to project the image information to be projected onto a suitable projection plane, wherein the projection plane is a suitable alternative plane to a roadway plane in the driver's field of vision.

[0079] The embodiments and advantages presented and described with reference to a display device also apply accordingly to a head-up display and a vehicle, and vice versa.

[0080] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. All features and combinations of features mentioned above in the description, as well as those subsequently mentioned in the description of the figures and / or shown in the figures, are usable not only in the combinations specified, but also in other combinations and / or individually.

[0081] The invention will now be explained in more detail with reference to a preferred embodiment, which is not to be understood as limiting, and with reference to the accompanying drawings, which are also not to be understood as limiting.

[0082] They show: Fig. 1. A schematic diagram illustrating the functioning of an embodiment of an AR head-up display installed in a vehicle according to the invention, with an embodiment of a display device according to the invention. Fig. 2 a schematic diagram to explain the "Scheimpflug rule" known from the prior art, Fig. 3 a schematic diagram to illustrate the optical effect of the display device according to the invention Fig. 1, Fig. 4 an excerpt of an exemplary beam path within the head-up display according to the invention Fig. 1 with the display device according to the invention made of Fig. 1 with a wedge-shaped optical refractive element, Fig. 5 parts of the display device according to the invention made of Fig. 1 in perspective representation, and Fig. 6. A side view of the display device Fig. 5.

[0083] Fig. Figure 1 shows a schematic diagram to explain the functioning of an embodiment of an embodiment of an AR head-up display 40 installed in a vehicle 100 according to the invention, with an embodiment of a display device 50 according to the invention, wherein these AR head-up display 40 according to the invention are a windshield head-up display 40.

[0084] This schematic diagram clearly illustrates the basic functionality of the AR Head-Up Display 40 according to the invention in a vehicle 100 according to the invention.

[0085] To project a virtual image 11A or image information 11A to be projected into the field of vision of a driver 20 of the vehicle 100, an information signal 61, which contains corresponding data of the image information 11A to be projected, is first transmitted to an image generation device 60, more precisely to an image generation unit 62 of the image generation device 60. The image generation unit 62 generates image data, not further specified here, from the information signal 61 or from the data contained therein. As in this embodiment of a head-up display 40 according to the invention, the image data can be corrected by means of a correction unit 63, which is also part of the image generation device 60, in particular to reduce or even completely compensate for systematic imaging errors, such as chromatic aberrations that can occur along the beam path.Subsequently, an output signal, also not further specified, containing the corrected image data, can be generated by means of the image output unit 64. The output signal with the corrected image data is transmitted to the display device 50 according to the invention, in particular to its display display 52, which in the exemplary embodiment is located in . Fig. 1 an LCD display 52 which can be backlit by means of an associated backlighting device 51.

[0086] The display 52 generates a visual display from the received image data, visually representing the image information contained in the image data. The display 52 emits light beams 10 that represent the image information to be projected into the driver's field of vision 20.

[0087] The display 52 is arranged at an angle of inclination in order to project the virtual image 11A not in a vertical plane, but in a projection plane inclined at a defined projection plane inclination angle, based on the "Scheimpflug principle", which will be explained below using the Fig. 2 and Fig. 3 is explained:

[0088] Fig. Figure 2 shows a schematic diagram of the "Scheimpflug rule" known from the prior art, which states that the image plane VE1 or B or B1, the focal plane HE and the objective plane VE2 or P or P1 intersect in a common straight line, with vertical planes VE1, B, HE, VE2, P that are perpendicular to the optical axis A, at infinity.

[0089] This results in a flat object 10, which lies obliquely to the focal plane HE as in the lower part of Fig. 2 (in the image plane B1 inclined by the angle α1), is only completely sharp in the area of ​​the line of intersection of the focal plane HE and the lens plane P. However, if the inclined, planar object 10 is to be sharply imaged in its entirety, for example, photographed in sharp focus, the lens plane P of the camera must be aligned according to the "Scheimpflug condition" as described in the lower part of Fig. 2 shown, are inclined (by the angle α2 => inclined lens plane P1) so that the lens plane P1 and the plane of the image to be photographed B1 intersect and the resulting line of intersection falls into the focal plane HE.

[0090] The same applies to the projection of an image 10, i.e., to the generation of a projected image 11 or 11A, such as the projection of an image 10 displayed by means of a display 52, since a projection is nothing other than an optical imaging process. If the image plane of the image 10 to be projected is vertically oriented (vertical plane VE1, image plane B), a vertical, virtual image 11 is obtained in the vertical plane VE2 or a vertical projection plane P (cf. Fig. 2 above). If the image to be projected 10 or its image plane B is tilted by the angle of inclination α1, so that the image 10 lies in the image plane B1, a virtual image 11 is obtained, or an image projected into the projection plane P1, due to the "Scheimpflug condition" with a suitable optical element or system 12, which is tilted by a projection plane inclination angle α2, and the projection plane P1 is tilted by the angle α2 to the corresponding vertical plane VE2 or P (cf. Fig. 2 below).

[0091] To increase the projection plane tilt angle α2, one possibility is to further increase the tilt angle α1 of the image plane. As explained at the beginning, this is only possible to a limited extent, especially when using a TFT display as the display 52, because with increasing display tilt angle α1, the contrast deteriorates to such an extent beyond a certain display tilt angle α1 that sufficient projection quality can no longer be achieved.

[0092] With a display device according to the present invention, for example with the display device 50 made of Fig. 1, however, the projection plane tilt angle α2 can be increased, and in particular, this can be done without increasing the display tilt angle α1.

[0093] This will be demonstrated below using the following examples. Fig. 3 explained, where Fig. 3 a schematic diagram to illustrate the optical effect of the display device 50 according to the invention Fig. 1 shows.

[0094] As previously based on Fig. As explained in section 2, a display tilt angle α1, or a tilt of the projected image 10 by the angle α1, leads to a tilt of the virtual, projected image 11 by the angle α2, or to a tilt of the projection plane P by the angle α2 (=> P1). If, instead of the optical element or system 12, another suitable optical element or system 12A is used, which in particular influences the direction of the light rays, for example by refraction as in a display device 50 according to the invention, a greater tilt of the projection plane (P1=> P2) can be achieved without increasing the display tilt angle α1, and the virtual image 11A, in particular an increase of the projection plane tilt angle from α2 by an angular amount α4 to a tilt angle α3, can be achieved, which corresponds to a display tilt angle α5 with α5 > α1.

[0095] To increase the projection plane tilt angle α2 achievable solely through display tilt (see Fig. 2 and Fig. 3) by the additional angle magnitude α4 (see below). Fig. 3), so that the virtual image 11A is in a projection plane inclination angle α3 defined by the defined angle α3 (see Fig. 3) is projected onto the inclined projection plane P2, but without the display tilt angle α1 (see below). Fig. 2 and Fig. 3) to enlarge, the display device according to the invention has 50 Fig. 1 next to the display 52 an optical refractive element 54 and a filler material 53 with which a space between a display surface 57 and the optical refractive element 54 is filled (cf. Fig. 5 and Fig. 6).

[0096] In this embodiment, the optical refractive element 54 is formed by a wedge plate 54 made of a completely transparent optical plastic having a refractive index of n1 ≈ 1.5, and thus a refractive index similar to that of glass. The optical refractive element 54 can, for example, be made of a cycloolefin copolymer (COC).

[0097] The wedge plate 54 has a trapezoidal cross-section, with which the wedge plate 54 extends over the entire width in the transverse direction or width direction Q of the LCD display 52 (cf. Fig. 5 and Fig. 6) The LCD display 52 is in particular rectangular form, wherein the transverse direction of the LCD display 52 is perpendicular to the drawing plane of Fig. The wedge plate 54 is accordingly a three-dimensional refractive element 54 in the form of a prism with a trapezoidal cross-section, wherein the wedge plate 54 has a flat entrance surface 55 and a flat exit surface 56, which are inclined to each other at a defined angle about an axis extending transversely to the LCD display 52. ​​The wedge plate 54 is arranged relative to the LCD display 52 or its display surface 57 such that the flat exit surface 56 of the optical refractive element 54, facing away from the LCD display 52, extends parallel to the display surface 57 of the LCD display 52, while the entrance surface 55, facing the LCD display 52, is inclined to the display surface 57. In this embodiment, the wedge plate 54 tapers from an upper edge of the display to a lower edge of the display.

[0098] With such an optical refractive element 54, in particular with a wedge plate 54 designed and arranged in this way, the direction of the light rays 10 can be selectively changed by targeted refraction of the light rays 10, thereby achieving a particularly advantageous influence on the light rays 10 emitted by the display 52. ​​As a result, a particularly advantageous projection of the image information or a particularly advantageous virtual image 11A can be achieved. In particular, with such an optical refractive element 54, in particular with a wedge plate 54 designed and arranged in this way, an additional tilt of the projected image 11A can be achieved through the defined refraction of the light rays 10 and the resulting change in direction of the light rays 10.

[0099] The volume or space between the wedge plate 54 and the LCD display 52 is filled with a completely transparent filling material 53 (see figure). Fig. 5 and Fig. 6), wherein in this embodiment the filler material 53 is a completely transparent optical adhesive, for example an optical epoxy adhesive, which in particular also has a refractive index of n2 ≈ 1.5. By filling the gap with filler material 53, which has a similar or substantially the same refractive index as the optical refractive element 54 and which is also similar or substantially the same as the refractive index of glass, namely approximately 1.5, and thus similar or substantially the same as the refractive index of a display glass of the LCD display 52, negative effects caused by differences in optical density when passing from one optical medium to another, as would be the case in particular if the gap were filled with air, which has a refractive index of nL = 1.0, can be reduced to a minimum.In particular, this can reduce or avoid unwanted multiple refractions, opposite changes in direction and / or unwanted multiple reflections.

[0100] The change in direction of the light rays 10 due to refraction is in Fig. Figure 1 is schematically represented by arrows. The light rays 10 emitted by the LCD display 52 exit the LCD display 52 perpendicularly to the display surface 57 and enter the filler material 53 perpendicularly. At the interface or entry surface 55 with the optical refractive element 54, the light rays 10 are refracted and thus deflected in their direction. Due to the approximately identical refractive indices n1 and n2 of the filler material 53 and the refractive element 54, only a relatively small change in direction occurs, and therefore no further negative effect. However, upon exiting the optical refractive element 54 at the exit surface 56 into the air-filled environment with a refractive index of nL = 1.0, the resulting refraction leads to a significant change in the direction of the light rays 10.Due to the design of the wedge plate 54 and its arrangement with the exit surface 56 parallel to the display surface 57, in this embodiment a change in direction is effected in particular, which corresponds to an increased inclination of the display surface 57 and to an additional inclination angle α4 (cf. . Fig. 3) leads.

[0101] Thus, the light rays 10 now strike the reflection device 42 arranged in the beam path or its planar mirror 42 with a direction as if they had been emitted from a display 52, 51 with a larger display tilt angle α5 (cf. Fig. 3) From the flat mirror 42 of the reflection device 42, the light rays 10 are reflected further to the reflection device 41 or to its concavely curved mirror 41 and from there onto the inner surface 31 of the windshield 30, which is coated with a reflective layer. Due to the optical properties of the windshield and its inclination, a virtual image 11 is generated and projected directly into the driver's field of vision 20.

[0102] For further details on the basic design and functionality of an AR head-up display, reference is made, for example, to the aforementioned US 11,175,500 B2.

[0103] Fig. Figure 4 shows a section of an exemplary ray path of the light rays 10 within the head-up display 40 according to the invention. Fig. 1 with the display device 50 according to the invention Fig. 1 with a wedge-shaped optical refractive element 54. In this representation, the path of the light rays 10 through the wedge plate 54, further to the planar mirror 42, the reflection at this to the concavely curved mirror 41 and the reflection at this towards the windshield (not shown here) can be seen in particular.

[0104] Fig. 5 and Fig. Figure 6 shows highly magnified schematic diagrams of the design and arrangement of the optical refractive element 54 and of the filling material 53 in the space above or in front of the display surface 57, wherein Fig. 5 parts of the display device 50 according to the invention. Fig. 1 in perspective representation shows and Fig. 6 a side view of the display device 50 from Fig. 5.

[0105] In addition to the described possible configurations, a large number of other embodiments are possible within the scope of the applicable patent claims.

[0106] The Fig. Figure 7 shows a further embodiment of the head-up display (40) and the display device (50) according to the invention. The concavely curved reflection device (41) is shown in this Fig. 7 is shown as planar for the sake of simplicity, but functions as a magnifying mirror, as in the previous embodiments, which usually has a curvature.

[0107] The display device (50) according to the invention comprises an LCD display (52), which is preferably designed as a so-called TFT display, with a display surface (57) and a display illumination device (58). The display illumination device (58) backlights the LCD display (52) to generate the image, wherein the display illumination device (58) is arranged at an angle to the LCD display (52) so that different path lengths are provided for the light rays (10a, 10b). This results in the image projected to the driver being displayed at an angle.

[0108] Furthermore, an optical refractive element (54) in the form of a wedge plate is provided, which has a first refractive index (n1). The wedge plate (54) also has an entrance surface (55) for incident light from the LCD display (52) and an exit surface (56) for emitting the light from the LCD display (52) received via the entrance surface (55). The entrance surface (55) of the wedge plate (54) is arranged at an angle to the exit surface, so that incident light rays (10a, 10b) with additional path lengths are emitted again from the exit surface (56) and with refraction of the light rays (10a, 10b).

[0109] The entry surface (55) of the wedge plate (54) is arranged parallel to the display surface (57), with the wedge plate (54) and the LCD display (57) being connected to each other via a filler material (53). The filler material (53) has a second refractive index (n2), which is preferably selected such that no refraction of the light rays (10a, 10b) occurs when passing from the display surface (57) into the filler material (53), wherein the second refractive index (n2) preferably corresponds to the refractive index of the display surface (57). Furthermore, the second refractive index (n2) and the first refractive index (n1) are selected relative to each other such that the light rays (10a, 10b) are also not refracted when passing from the filler material (53) into the wedge plate (54) via the entry surface (55). Reference symbol list: 100 Vehicle according to the invention with a head-up display according to the invention with a display device according to the invention 10 Image information to be projected into a driver's field of vision, represented by his light rays 10a first light ray carrying the image information to be projected with a first path length 10b second light ray carrying the image information to be projected with a second path length 11 Image information projected in the projection plane without a display device according to the invention, virtual image 11A Image information projected into the projection plane with a display device according to the invention, virtual image 12 optical element 20 drivers 30 Windscreen 31 Inner surface area of ​​a windshield 40 Head-Up Display according to the invention 41 Concave curved reflection device, in particular concave curved mirror 42 Plane reflection device, in particular a plane mirror 43 optical components of the head-up display that direct the generated image information onto the projection surface. 50 Display device according to the invention 51 Backlighting device 52" LCD display with a glass display surface 53 Filling material with refractive index n2 54 Optical refractive element in the form of a wedge plate with refractive index n1 55 Entrance area 56 Exit area 57 Display surface 60 Image generating unit 61 Information signal of an image information to be projected 62 Image generation unit 63 correction units 64 Image output unit A optical axis α1 Inclination angle of a displayed image or associated display plane or display surface relative to the associated vertical plane α2 resulting inclination angle of the projected image or the projection plane relative to the associated vertical plane without the display device according to the invention α3 resulting inclination angle of the projected image or the projection plane relative to the associated vertical plane with a display device according to the invention α4 additional inclination angle of the projected image or the projection plane relative to the associated vertical plane caused by an optical refractive element and filling material of a display device according to the invention α5 theoretical display tilt angle that would be required to achieve a resulting projection plane tilt angle as with a display device according to the invention, but without such a device B, B1 Image plane n1 Refractive index of the filling material n2 Refractive index of the optical refractive element nL Refractive index of air P, P1 Projection plane without display device according to the invention P2 Projection plane with display device according to the invention HE Main Level Q Display direction (horizontal), width direction VE1 first vertical plane VE2 second vertical plane QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] US 11,175,500 B2 [0008, 0102] Cited non-patent literature

[0000] https: / / de.wikipedia.org / wiki / Scheimpflugsche Regel, last accessed on April 30, 2023

[0005]

Claims

[1] Display device (50) for a head-up display (40), in particular for an AR head-up display (40), comprising: a display display (52) with a display surface (57), and at least one optical refractive element (54) with a first refractive index (n1); wherein the at least one optical refractive element (54) has an entrance surface (55) and an exit surface (56) and is arranged at least partially in the beam path of a light (10) emitted by the display (52), such that at least a part of the light (10) emitted by the display (52) during operation of the display device (50) passes through the optical refractive element (54), and wherein the optical refractive element (54) is designed and arranged relative to the display (52) in such a way that the spatial orientation of an image information (10) to be projected is changed in a defined manner by an image information (10) displayed on the display (52) as a result of the passage of the associated emitted light (10) through the optical refractive element (54), characterized by , that there is a space between the display surface (57) of the display display (52) and the entrance surface (55) of the optical refractive element (54), which is at least partially filled with a filler material (53) made of a material that is at least partially transparent. [2] Display device (50) according to claim 1, characterized by, that the display display (52) is a TFT display (52), in particular an LCD display (52), TFT display or an OLED display, and is configured to be arranged inclined with a defined display tilt angle (α1) relative to an optical principal plane (HE). [3] Display device (50) according to claim 1 or 2, characterized by , that the defined display tilt angle (α1) is 0 degrees to 45 degrees, preferably more than 0 degrees, but particularly not more than 40 degrees, especially preferably not more than 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees or 5 degrees. [4] Display device (50) according to any one of the preceding claims, characterized by , that the optical refractive element (54) is designed to change the tilt angle (α2 => α3) of the projected image information (11 =>11A) in a defined manner in a head-up display (40). [5] Display device (50) according to any one of the preceding claims, characterized by, that the optical refractive element (54) is at least partially wedge-shaped, in particular as a wedge plate (54), wherein the exit surface (56) has or is a planar surface (56), and the planar surface defines an exit plane (56), wherein the optical refractive element (54) is arranged relative to the display (52) such that the exit plane (56) is oriented parallel to the display surface (57). [6] Display device (50) according to any one of the preceding claims, characterized by , that the optical refractive element (54) has a constant geometric cross-section in the width direction (Q) of the display (52), with reference to a functional operating state of the display (52). [7] Display device (50) according to claim 5 or 6, characterized by , that the wedge-shaped optical refractive element (54) tapers from an upper edge of the display (52) to a lower edge of the display (52). [8] Display device (50) according to any one of the preceding claims, characterized by , that the optical refractive element (54) has at least in certain areas, in particular the entire optical refractive element (54), a refractive index (n1) of 1.0 to 2.0, in particular a refractive index (n1) that is greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and in particular less than 2.0, 1.9, 1.8, 1.7 or 1.

6. [9] Display device (50) according to any of the preceding claims, characterized by , that the filling material (53) has a second refractive index (n2), wherein the refractive index (n2) of the filling material (53) is in particular greater than 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and in particular less than 2.0, 1.9, 1.8, 1.7 or 1.

6. [10] Display device (50) according to claim 9, characterized by , that the second refractive index (n2) (n1) is equal to the first refractive index or differs from it by no more than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%. [11] Display device (50) according to any of the preceding claims, characterized by , that the optical refractive element (54) is connected to the display surface (57) at least in certain areas, in particular by means of a material bond, preferably by means of the filling material (53). [12] Head-up display (40), in particular AR head-up display (40), with a display device (50) for displaying image information (10) to be projected, characterized by , that the head-up display (40) has a display device (50) according to one of claims 1 to 11. [13] Head-Up Display (40) according to claim 12, characterized by, that the head-up display (40) is designed such that, in a functional installation state of the head-up display (40) in a vehicle (100), the display display (52) is or can be arranged inclined with a defined display tilt angle (α1) relative to a principal optical plane (HE), in particular relative to a vertical principal optical plane (HE) with reference to a functional installation state of the head-up display (40) in a vehicle (100), wherein the defined display tilt angle (α1) is 0 degrees to 45 degrees, preferably more than 0 degrees, but in particular not more than 40 degrees, and particularly preferably not more than 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees or 5 degrees. [14] Head-Up Display (40) according to claim 12 or 13, characterized by, that the head-up display (40) is configured to project image information (11A) inclined by a defined projection plane inclination angle (α3) relative to a principal optical plane (HE), in particular relative to a vertical principal optical plane (HE) with reference to a functional installation state of the head-up display (40) in a vehicle (100), wherein the projection plane inclination angle (α3) is greater than the projection plane inclination angle (α2) achievable according to the Scheimpflug condition with a given display inclination angle (α1), in particular by an additional angular amount (α4) of at least 1 degree, 2 degrees, 3 degrees, 5 degrees, 7 degrees, 8 degrees, 10 degrees, 12 degrees, 15 degrees, 20 degrees or 25 degrees. [15] Vehicle (100), in particular motor vehicle (100), with a head-up display (40), characterized by , that the vehicle has a head-up display (40) according to one of claims 12 to 14.

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