Display device with a series of several floating real image surfaces for an optical quality improvement, as well as a vehicle with such a display device

Abstract

The invention relates to a display device composed of several floating display modules, wherein: - each individual module comprises an image-generating display having a flat display surface and a flat imaging optic arranged at a predetermined axial distance therefrom, which extends along the display surface and is designed to image a display content generated in the display surface onto a real image surface floating freely in the air and located on a user-side side of the imaging optic facing away from the display; and - the individual display surfaces are arranged at predetermined lateral distances from one another and at predetermined angles of incidence to one another such that the associated floating real image surfaces each adjoin one another seamlessly and thereby form an uninterrupted composite floating real image surface which is concave from the user's perspective.

Description

[0001] The invention relates to a display device that can be designed in particular for installation in a vehicle. The invention is therefore also directed to a vehicle equipped therewith, which may be a motor vehicle or another type of land, air, or water vehicle.

[0002] Optical display devices intended for installation in vehicles are known from the documents CN 1 12 776 823 A, DE 10 2020 107 664 A1 and WO 2023 / 186 717 A1.

[0003] A floating display comprising lens arrays is known from US 11 448 898 B2.

[0004] WO 2017 / 155748 A2 describes floating displays based on microlens arrays (MLAs) or lens systems in the form of reconvergent films for generating a floating display in which a real image floats in the air in front of the viewer. Lens systems of this type generate the floating real image with high efficiency and are both wavelength- and polarization-independent. Furthermore, it is known, for example, from JP 2014-067071 A, to avoid touching a touchscreen with fingers by generating a real display image floating in a defined spatial region above the imaging means using an imaging means arranged above a display (for example, a lens or a multi-path mirror comprising a planar arrangement of a large number of orthogonal mirror surface pairs).

[0005] However, this poses the problem that larger viewing angles can lead to severe limitations, such as double images or a deterioration in image quality and color performance. To prevent this, the viewing angle range must be restricted, which is usually achieved by correspondingly limiting the image size of the floating real image.

[0006] It is an object of the invention to provide an alternative and / or improved display concept, in particular for vehicles, with which such problems can be avoided.

[0007] This object is achieved by a display device according to claim 1 and by a vehicle equipped therewith according to the independent claim. Further embodiments are specified in the dependent claims. All further features and effects mentioned in the claims and in the following description for the display device also apply to the vehicle, and vice versa.

[0008] According to a first aspect, a display device is provided which can be designed in particular for installation in a vehicle. The vehicle can be a motor vehicle, but also any other land, air, or water vehicle. When used in a vehicle, all spatial orientation terms used herein, such as "top," "bottom," "horizontal," "vertical," etc., unless otherwise stated, refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical directions of the vehicle.

[0009] The display device consists of several floating display modules. Each of these modules comprises an image-generating display with a flat display surface and a flat imaging optic extending at a predetermined axial distance from the display surface. The terms "axial distance" and "lateral distance" used herein refer to an optical axis of the respective display module, which corresponds to a normal direction of its display surface.

[0010] The imaging optics are designed to project display content generated in the display surface onto a real image surface floating freely in the air, located on a side of the imaging optics facing away from the display and facing the user. The floating real image surface can also be essentially flat and extend approximately parallel to the display surface. Even though a largely parallel alignment of all optically relevant surfaces within a module can be advantageous, for example, for its spatial compactness, ease of manufacture and / or optical properties, curved surfaces and / or surfaces angled to the display surface in a predetermined manner are also possible for the imaging optics and / or the floating real image surface, which can mean greater design freedom and enable the achievement of additional associated effects.For similar reasons, the individual modules can, but do not have to, all be of the same design and dimensions and / or all be angled identically to one another in pairs in order to achieve the effects mentioned below.

[0011] The display surfaces of the individual modules are arranged at predetermined lateral distances from one another and at predetermined angles to one another such that the corresponding floating real image surfaces adjoin one another seamlessly, thereby forming a continuous (i.e., in particular, one without cracks or gaps) composite floating real image surface that is concave from the user's perspective. In other words, the respective adjacent floating real image surfaces, which adjoin one another seamlessly along a straight line, are adjacent to one another at a predetermined angle of less than 180° from the user's perspective.This angle, which can be between approximately 150° and approximately 170°, for example, is measured in a plane perpendicular to the said straight line and generally corresponds (among other things when all optical surfaces within a module are aligned parallel) to the said angle of incidence of the individual display surfaces (which, however, in contrast to their real images, which result in the floating real image surfaces, are not directly adjacent to one another, but have the said lateral distance from one another, which can be used, for example, for fastening, cooling, etc. of the individual modules).

[0012] The individual modules can be firmly connected to one another within the display device, for example, via fastening means designed to maintain the specified distances and angles of inclination, such as a rear mounting plate, a protective housing, or mounting strips arranged between two modules, and much more. Alternatively, the individual modules can also be attached not directly to one another, but rather to a higher-level system, such as a vehicle in which the display device is installed, in the aforementioned mutual arrangement.

[0013] One idea of ​​the display device proposed here is to divide the imaging unit into individual modules (each designed for floating real image generation) and to orient these modules at different angles so that the limitations of the viewing angle range mentioned above, which are known for floating displays from the prior art, are eliminated. This arrangement also offers the additional advantage that the transitions between the individual visible display planes are uninterrupted, as they are floating, even though the imaging unit itself has interruptions between its individual modules. These interruptions can be useful when the combined display area is enlarged, for example, for the attachment, insulation, and / or cooling of the correspondingly larger imaging unit.In addition, the proposed arrangement results in a real floating image with a depth effect (curvature), which brings additional benefits through the possibility of depicting depth or a better recording for the viewer, for example with regard to ergonomics or the distance of the image from his eyes.

[0014] In other words, the concave display surface (composite real floating image surface) at least partially surrounds a spatial area around its user, enabling a particularly natural and pleasant perception and thus ergonomic effect of the display content depicted in this composite image surface. The displayed floating image is real, meaning it can be captured by light-sensitive material and made visible to everyone by a light-diffusing surface, if such a material or surface were brought into its image position.

[0015] The aforementioned imaging optics, particularly through a suitable choice of their effective focal length, allow the real image to be generated at the most suitable and comfortable image distance from the user's eyes. This image distance can be significantly shorter, especially compared to a hard display surface or virtual image generation. It can be less than one meter or even less than half a meter, for example. Such image distances are ideal (similar to a computer screen), for example, for displaying and reading information in small print and / or with high resolution.

[0016] In principle, any imaging technology is suitable for the respective display. In particular, it can be designed to dynamically generate the required or desired display content in a two-dimensional pixel matrix. For example, it can be designed as a light-transmitting or light-emitting flat panel display, such as a liquid crystal display (LCD) or a µLED or OLED display, or alternatively as a projector-based imager or a waveguide-based display.

[0017] According to one embodiment, the imaging optics of each module are designed such that a light beam generated by its display surface, which transports the display content, only reaches an eyebox predetermined for the user's eyes (in particular, an individual user); and the sizes and angles of incidence of the individual display surfaces are selected such that the maximum aperture angle of the respective floating real image surface required to illuminate the entire eyebox is smaller than a predetermined maximum aperture angle. The maximum aperture angle required for the respective floating real image surface is defined as the largest angle measured at the edge of this image surface between its surface normal and a straight line connecting the same image edge point with a furthest eyebox edge point.

[0018] As is usual, the eyebox is understood to be the area of ​​space from which the displayed floating real image is fully visible. In other words, the light beam is essentially limited to this area of ​​space. The eyebox can be dimensioned accordingly for use by a single person, for example. For example, when used in a vehicle, the eyebox can be limited to the width and height of a seat intended for the user or their headrest, so that no other people in the vicinity can see the floating real image. This allows confidential content to be shown to the user (“privacy”). On the other hand, other people in the vicinity of the user, such as other vehicle occupants or passers-by, are not visually disturbed by this display because they cannot see it.In addition, by spatially restricting the light beam to an eyebox designed for individual use, the light energy required to generate it can be saved.

[0019] In this embodiment, the predetermined maximum opening angle can be, for example, less than 45°, less than 35°, or even less than 25°. For this purpose, just three to five correspondingly small-sized individual modules in the angled arrangement presented here, for example in succession in the horizontal direction, can be sufficient to cover a large horizontal field of view of, for example, more than 40°, 60° or 80° with high image quality (i.e. in particular free of double images and / or with largely consistent sharpness, scaling, color performance, homogeneity and / or brightness). The same can of course also be provided in the vertical direction in order to expand the user's field of view that can be covered by the composite floating real image, even in the vertical direction, while maintaining a consistently high image quality.

[0020] Alternatively or in addition to the above embodiment, the angle of incidence of the individual display surfaces can be dimensioned such that their associated floating real image surfaces have a substantially identical image distance from the above-mentioned eyebox, which is defined as the distance from the center of the respective floating real image surface to the center of the eyebox. This can increase comfort, particularly in the case of an eyebox designed for a single user, in that the combined, and thus fundamentally arbitrarily large, floating real display surface has a largely constant image distance from the user's eyes across the entire display surface. This can be particularly ergonomic for reading, working, or gaming, for example, and thus enable the user to use the device for longer periods without becoming tired.

[0021] The imaging optics of each module can, for example, comprise a microlens array (MLA) or an arrangement of two or more microlens arrays arranged consecutively in the beam path, which is / are designed to image the display surface or the display content generated therein onto the associated real image surface floating freely in the air. The number of microlens arrays and their lens or surface geometry can be selected differently depending on the requirements of a specific application in order to enable different aperture angles and imaging properties (such as magnification, image distance, etc.). Alternatively or additionally, the imaging optics can also comprise one or more other types of imaging and / or deflecting optical elements for the same purpose, such as a film or plate structured (e.g., plane-parallel) with mirrors, prisms, or other refractive and / or reflective microstructures.

[0022] Due to the overall flat design of the formation optics, the respective module can in particular have a total thickness of less than 5 cm, for example of approximately 3 to 4 cm, approximately 3 to 3.5 cm or even less, which can further facilitate its integration in a vehicle, where the installation space is typically limited.

[0023] The two or more microlens arrays arranged consecutively in the beam path can be arranged and configured, particularly mirror-symmetrically to each other in the beam propagation direction. This allows for particularly good optical functionality, in particular a particularly high imaging quality for the floating real image.

[0024] Optionally, each module can include a cover plate or layer arranged on the user-facing side of the imaging optics, forming a user-facing module surface and designed to transmit the light beam generated by its display surface. In this case, the floating real image surface of the respective module lies in the air between its cover plate or layer and an eyebox predetermined for the user's eyes.

[0025] The cover plate / cover layer can be made of any material that is transparent to the display light, for example plastic or glass. It, and in particular its user-facing surface, can be planar (i.e. flat), for example. However, the cover plate / cover layer can also have a free-form surface on one or both sides to produce a predetermined optical effect and / or a predetermined geometry, for example of a vehicle element. Last but not least, the cover plate / cover layer can also serve to mechanically protect the optical components of the module, in particular its imaging optics. In the version with MLAs, the cover layer can be formed on a user-facing surface of the last microlens array in the beam path. Alternatively, the cover plate can be formed separately from the microlens array or the module.the arrangement of the microlens arrays, which means additional design freedom for both the last microlens array in the beam path and for the cover plate itself.

[0026] In order to make it significantly more difficult for the user and other persons to see into the interior of the module through the cover plate or layer, or even to prevent it almost completely, the cover plate or layer can be designed to be at least partially opaque to ambient light incident from outside. To this end, it can comprise, for example, a perforated film, the addition of particles, coloring, tinting, a polarization filter and / or an LC layer that can be switched on uniformly (i.e. as a whole) or in segments. In particular, the cover plate or layer can have a higher transmittance for the outward-facing display light than for the ambient light incident from outside, for example by means of layers / structures that block light on one side or suitable polarization filters, if appropriate in combination with appropriately polarized display light.

[0027] Through this reduction in transparency, the cover plate / cover layer can be darkened to such an extent that it forms a dark or even black image background for a particularly high-contrast display of the floating real image. In other words, the cover plate / cover layer can serve as a contrast medium for displaying the floating real image with a desired contrast through its targeted darkening. Since the ambient light, unlike the display light, has to pass through the cover plate / cover layer twice to illuminate the interior of the respective module when viewed from the outside, this ambient light can also be attenuated at least twice as much as the display light by light-absorbing particles, perforation, or a suitable polarization filter in the cover plate / cover layer.For example, a perforated film with a transmittance of about 40% can ensure perfect visibility of the floating real image for the user because it transmits less than 16% of the disturbing ambient light and therefore forms an almost black image background.

[0028] According to a further aspect, the above-mentioned vehicle, in particular a motor vehicle, is provided. The vehicle comprises a passenger compartment and one or more display devices of the type presented herein, each of which is configured to generate a real image suspended in the air in the passenger compartment or on the outside of the vehicle and is arranged accordingly in the passenger compartment or in an exterior vehicle element.

[0029] For this purpose, the display devices can be integrated, for example, in an instrument panel, in armrests, A-, B-, C- or D-pillars, vehicle doors and / or tailgates.

[0030] The above aspects of the invention and their embodiments and specific configurations are explained in more detail below using an example shown in the accompanying drawing. The drawing is to be understood as a purely schematic illustration of the basic design and functional principle, i.e., not to scale. It shows: Fig. 1 shows a cross-sectional view of the basic structure of a display device according to an embodiment of the invention.

[0031] All of the various embodiments, alternatives and specific design features of the 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 used in the Fig. 1, in particular alternatively or in addition to the features shown therein. Therefore, they will not be repeated again below. The same applies accordingly to the definitions and effects already given above with regard to individual features that are described in Fig. 1 are shown.

[0032] Fig. 1 shows a highly simplified schematic cross-sectional view (here purely as an example, a horizontal longitudinal section) of a display device 1 according to an exemplary embodiment of the invention. In this example, the display device 1 is designed for individual use by a user 2. In order for the user to be able to see the display in the intended display quality, their eyes must be located in a predetermined spatial area (eyebox E). The display device 1 can, for example, be integrated as an interior or exterior display in a vehicle (not shown), in particular a motor vehicle. As already mentioned, in this case, the spatial orientation terms such as "top", "bottom", "left", "right", "horizontal", "vertical", etc. refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical directions of the vehicle.

[0033] The display device 1 is set in Fig. 1 consists purely of an example of three individual floating display modules 3, which in turn are designed and dimensioned identically to one another purely by way of example. However, according to the same arrangement principle, two, four, five or more individual modules 3 of this type can also be provided in the display device 1. Each module 3 comprises an image-generating display 4 with a flat display surface 5 and a flat imaging optics 6, which in this example is designed as a microlens array (MLA) and extends at a predetermined constant axial distance from the display surface 5. The terms "axial distance" and "lateral distance" refer to an optical axis of the respective display module 3, which corresponds to a normal direction N of its display surface 5.

[0034] The imaging optics 6 are designed to project the entire display surface 5 or a display content generated in the display surface 5 onto a real image surface 7 floating freely in the air, which is located on a user-side side of the imaging optics 6 facing away from the display 4. In this example, the respective floating real image surface 7 is also planar and extends approximately parallel to the associated display surface 5, so that their normal directions N also approximately coincide.

[0035] The display surfaces 5 of the individual modules 3 are arranged at predetermined lateral (i.e. side) distances from one another and at predetermined angles of incidence to one another such that the associated floating real image surfaces 7 each adjoin one another seamlessly and thereby produce an uninterrupted composite floating real image surface R which is concave from the perspective of the user 2. In other words, the respective adjacent floating real image surfaces 7, which adjoin one another seamlessly along a straight line, are arranged at a predetermined angle of less than 180° to one another from the user's perspective. This angle, which may be approximately 150°, 160° or 170°, is measured in a plane perpendicular to the said straight line (which corresponds to the drawing plane of the Fig. 1) and in this example also corresponds to the angle of incidence of the individual display surfaces 5 (which, however, in contrast to their real images, ie the floating real image surfaces 7, do not directly border each other, but Fig. 1 have a clearly visible lateral distance from each other, which can be used, for example, for fastening, cooling, etc. of the individual modules 3).

[0036] This arrangement ensures that the maximum required opening angle β or γ of the respective floating real image area 7 to illuminate the entire eyebox E is smaller than a predetermined maximum opening angle at which the respective floating real image area 7 can be seen from the entire eyebox E with the intended optical quality. As shown in Fig. 1, the maximum required opening angle β or γ of the respective floating real image surface 7 is defined as the largest angle measured at the edge of the respective image surface 7 between its surface normal N and a light ray L connecting the same image edge point with a furthest away eyebox edge point.

[0037] If one were to instead use a display area of ​​the same size as in Fig. 1 with a single module 3, i.e. with a flat display surface 5 three times as large, the maximum required opening angle would also be correspondingly larger, which would lead to considerable losses in quality such as double images, reduced brightness, impaired color representation, inhomogeneities, etc., particularly in the edge areas of the display surface or in the edge areas of the Eyebox E.

[0038] As an additional positive effect of the angled arrangement of the individual modules 3 presented here, the concave display surface (i.e., the composite real floating image surface R) partially surrounds a spatial area around its user 2, which enables a particularly natural and pleasant perception and thus ergonomic effect of the display content presented in this composite display surface. Furthermore, with a seamless floating display surface R, the lateral distances still possible between the individual modules 3 are extremely useful for their mounting, cooling, etc. List of reference symbols 1 display device 2 users 3 single floating display module 4 image-generating display 5 display area 6 Imaging optics 7 floating real image area of ​​a module L light beam R continuously composed floating real image surface E Eyebox N Normal direction

Claims

[1] Display device (1) composed of several floating display modules (3), wherein: - each individual module (3) comprises an image-generating display (4) with a flat display surface (5) and a flat imaging optic (6) arranged at a predetermined axial distance therefrom, which extends along the display surface (5) and is designed to image a display content generated in the display surface (5) onto a real image surface (7) floating freely in the air, which is located on a user-side side of the imaging optic (6) facing away from the display (4); and - the individual display surfaces (5) are arranged at predetermined lateral distances from one another and at predetermined angles of incidence to one another such that the associated floating real image surfaces (7) each adjoin one another seamlessly and thereby form an uninterrupted composite floating real image surface (R) which is concave from the user's perspective. [2] Display device (1) according to claim 1, wherein - the imaging optics (6) of each module (3) are designed such that a light beam generated by its display surface (5) with the display content only reaches an eyebox (E) predetermined for the user's eyes; and - the sizes and angles of incidence of the individual display surfaces (5) are dimensioned such that a maximum opening angle of the respective floating real image surface (7) required to illuminate the entire eyebox (E), defined as the largest angle measured at the edge of this image surface (7) between its surface normal (N) and a light beam (L) connecting the same image edge point with a furthest eyebox edge point, is smaller than a predetermined maximum opening angle. [3] Display device (1) according to claim 2, wherein - the predetermined maximum opening angle is less than 45°, preferably less than 35°, particularly preferably less than 25°. [4] Display device (1) according to one of the preceding claims, wherein - the imaging optics (6) of each module (3) are designed such that a light beam generated by its display surface (5) with the display content only reaches an eyebox (E) predetermined for the user's eyes; and - the angles of incidence of the individual display surfaces (5) are dimensioned such that their associated floating real image surfaces (7) have a substantially equal image distance from the eyebox (E), which is defined as a distance from a center of the respective floating real image surface (7) to an eyebox center. [5] Display device (1) according to one of the preceding claims, wherein - the imaging optics (6) of each module (6) comprises a microlens array or an arrangement of two or more microlens arrays following one another in the beam path, which is / are designed to image the display surface (5) or the display content generated therein onto the associated real image surface (7) floating freely in the air. [6] Display device (1) according to claim 5, wherein - the two or more microlens arrays following one another in the beam path are arranged and formed mirror-symmetrically to one another in the beam propagation direction. [7] Display device (1) according to one of the preceding claims, wherein - the imaging optics (6) of each module (3) comprises a film or plate structured with mirrors, prisms or other refractive and / or reflective microstructures, which is / are designed to image the display surface (5) or the display content generated therein onto the associated real image surface (7) floating freely in the air. [8] Display device (1) according to one of the preceding claims, wherein - each module (3) further comprises a cover plate or layer arranged on the user-side side of the imaging optics (6), which forms a user-side module surface and is designed to transmit the light beam with the display content generated by its display (4); and - the floating real image surface (7) of the respective module (3) lies in the air between its cover plate or layer and an eyebox (E) predetermined for user eyes. [9] Display device (1) according to claim 8, wherein - the cover plate or layer is opaque to ambient light incident on it from outside due to a perforated film, particle addition, coloring, tinting, a polarization filter and / or a segmentally or uniformly switchable liquid crystal layer to such an extent that it substantially prevents a view into the interior of the module (3). [10] Vehicle, in particular a motor vehicle, comprising: - an occupant compartment; and - at least one display device (1) according to one of the preceding claims, which is designed to generate a real image floating in the air in the passenger compartment or on the outside of the vehicle and is integrated accordingly in the passenger compartment or in an external vehicle element.

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