Display device with interference light suppression

Abstract

The present invention relates to a display device (1) having interference light suppression. [Solution] The display device (1) has a display panel (2) and a transparent element (3) positioned above (20) the display panel (2). The material of the transparent element (3) is selected so as not to cause an abrupt change in refractive index during the transition from the display panel 2 to the transparent element (3). The transparent element (3) has a curved top surface (30) designed to deflect incident interference light (IL) in the direction of a light trap (LT).

Description

Technical Field

[0001] The present invention relates to a display device having interference light suppression.

Background Art

[0002] The number and area of display devices in transportation means are continuously increasing. For example, display devices can be found commercially available as instrument panels for drivers, as central displays, and as displays for front-seat passengers.

[0003] Head-up displays are also increasingly found in transportation means. A head-up display, also called a HUD, is understood to mean a display system in which the presented content is inserted within the user's field of vision, so that the user can maintain their viewing direction. Such systems were initially mainly used in the aerospace field due to their complexity and cost, but are now also introduced into mass production in the automotive field.

[0004] A head-up display generally consists of an image generation unit (PGU), an optical unit, and a mirror unit. The image generation unit generates an image and uses at least one display element for this purpose. Most current head-up displays use LCD-based displays (LCD: liquid crystal display). The optical unit guides the image onto the mirror unit. The mirror unit is a partially reflective, light-transmissive plate. Thus, the user can see the content presented by the image generation unit as a virtual image and at the same time see the real world behind the plate. In the automotive field, the windshield is often used as the mirror unit, and the curved shape of the windshield must be taken into account in the presentation. Due to the interaction between the optical unit and the mirror unit, the virtual image is an enlarged presentation of the image generated by the image generation unit.

[0005] In another embodiment, these displays are positioned relative to the windshield so that they can be viewed across the windshield and virtual depth is provided directly by the distance to the windshield. Such displays are called scenic view displays. Currently, the image content of a scenic view display is reflected through a black-tinted area of ​​the windshield to prevent light from sunlight or other light sources from directly entering the display. Without this black-tinted area on the windshield, sunlight or external light would reach the display directly and overlap the image content as back reflection or back scattering. This could result in the driver becoming distracted or disturbed, which must be avoided at all costs.

[0006] In this regard, DE 10 2010 032 998 A1 describes a head-up display for an automobile having a projection device on which the image to be displayed is projected onto the windshield of the automobile, with the windshield acting as the coupling device. The projection device has a translucent cover directed toward the windshield, which is designed to reflect external light incident on the cover from the outside onto an absorbing surface. The absorbing surface is at least partially formed by an inner surface coating of the windshield.

[0007] WO 2019 / 238849 A1 describes an apparatus for generating a virtual image with interference light suppression. The apparatus comprises a light source, a display element for generating an image, and an anti-glare element. The anti-glare element has a curved surface.

[0008] Summary of the Invention The object of the present invention is to provide an improved display device having interference light suppression.

[0009] This objective is achieved by a display device having the features of claim 1. Dependent claims relate to preferred designs of the present invention.

[0010] According to a first aspect of the present invention, the display device comprises a display panel and a transparent element positioned above the display panel. The material of the transparent element is selected such that there is no abrupt change in refractive index during the transition from the display panel to the transparent element. The transparent element has a curved upper side designed to deflect incident interference light in the direction of the optical trap.

[0011] In the solution according to the present invention, the display panel is positioned beneath a cover, and its surface is curved so that incident light is appropriately deflected. In this case, the surface satisfies the requirements for a geometric anti-reflective coating. Furthermore, the material of the cover is selected so that there is no abrupt change in refractive index from the outer surface to the display panel. For this purpose, the cover is formed so that the space between the display panel and the curved surface is completely filled with the cover material. In this way, interfering back reflections are avoided. For example, the display device may be installed in a shaft so that incident interfering light is guided into a shaft wall that acts as an optical trap.

[0012] According to one aspect of the present invention, the display panel is designed to be planar. In this way, a display device can be realized using a commercially available display panel, which is advantageous in terms of manufacturing cost.

[0013] According to one aspect of the present invention, the display panel is positioned obliquely to the viewing direction. This allows the curvature of the transparent element to be reflected across the surface of the display panel. In this way, less material is required to manufacture the transparent element, which is advantageous in terms of material cost and the overall weight of the system.

[0014] According to one aspect of the present invention, the display panel is designed in a curved shape. In this embodiment, a display panel with a special shape is required. However, in contrast, the transparent element can be designed to be very thin, thereby reducing the overall weight of the system.

[0015] According to one aspect of the present invention, the display device has a transparent plate designed to reflect the image displayed by the display panel toward the user. By using a transparent plate such as a car windshield, it is possible to realize a scenic view display.

[0016] According to one aspect of the present invention, the transparent plate has a blackened region. Then, some image components of the display area of ​​the display panel are reflected through the blackened region of the plate, and other image components are reflected through the transparent region of the plate. The arrangement of the light traps can be individually selected according to a desired implementation form of the entire system.

[0017] According to one aspect of the present invention, a display device has a backlight designed such that the light emitted by the backlight illuminates the head positions of one or more users. For example, the light for backlighting a display panel may be formed to illuminate the head position of the driver of a car, or to illuminate a narrow cone of light from the driver's head position to the head positions of the front-seat occupants.

[0018] According to one aspect of the present invention, the light trap is designed as a light-absorbing wall. In this way, it can be ensured that there is no reflection of interference light emitted from the light trap.

[0019] According to one aspect of the present invention, a display device, either by itself or in combination with a further display device, forms a display strip. In such a display strip, the width of the common display area is significantly greater than the height of the display area. For example, the design as a display strip makes it possible to realize a display that extends across the entire width, or at least nearly the entire width, of a car dashboard.

[0020] According to one aspect of the present invention, optical shading in a display strip is implemented such that, for at least a portion of the display strip, image content is permanently and / or switchably visible to only one of a plurality of user positions. For example, optical shading may be implemented so that specific image content is visible only to the driver of a vehicle, or only to the front-seat occupants. On the one hand, this may be permanent, but it is also possible to individually switch the visibility of the image content as needed. Furthermore, it is possible to switch between an operating mode having an unrestricted public mode and an operating mode having a privacy mode via optical shading, i.e., the entire system can be designed as a switchable privacy display.

[0021] The display device according to the present invention is preferably used in means of transport. For example, the means of transport may be an automobile, but instead, it may be an aircraft, a railway vehicle, or a water vehicle. The use of the solution according to the present invention is possible, in particular, in all display and head-up display systems where interference light suppression is necessary or desirable. However, the display device according to the present invention may also be used in cinemas, near-eye displays, or general multimedia applications.

[0022] Further features of the present invention will become apparent from the following description and appended claims, in conjunction with the drawings. [Brief explanation of the drawing]

[0023] [Figure 1] A schematic diagram of a first exemplary embodiment of a display device according to the present invention is shown. [Figure 2] A schematic diagram of a second exemplary embodiment of the display device according to the present invention is shown. [Figure 3] A schematic diagram of a third exemplary embodiment of the display device according to the present invention is shown. [Figure 4] A schematic diagram of a fourth exemplary embodiment of the display device according to the present invention is shown. [Figure 5] Shows a schematic diagram of a first exemplary embodiment of a backlight. [Figure 6] Shows a schematic diagram of a second exemplary embodiment of a backlight. [Figure 7] Shows a schematic diagram of a transportation means using a display device according to the present invention.

Mode for Carrying Out the Invention

[0024] In order to better understand the principles of the present invention, embodiments of the present invention will be described in more detail below with reference to the drawings. In the drawings, the same or functionally identical elements are denoted by the same reference numerals and are not necessarily described again for each figure. It is understood that the present invention is not limited to the presented embodiments, and the described features may be combined or modified without departing from the scope of protection of the present invention defined by the appended claims.

[0025] FIG. 1 shows a schematic diagram of a first exemplary embodiment of a display device 1 according to the present invention. The display device 1 has a display panel 2 and a transparent element 3 disposed above the upper side 20 of the display panel 2. The transparent element 3 has a curved upper surface 30 designed to deflect incident interference light IL in the direction of the light trap LT. For example, the light trap LT can be formed by a light absorption wall 7 of a shaft in which the display device 1 or the display panel 2 and the transparent element 3 are installed. Only the light absorption wall 7 is shown in FIG. 1 instead of such a shaft.

[0026] The material of the transparent element 3 is selected so as not to cause an abrupt change in refractive index during the transition from the display panel 2 to the transparent element 3. For this purpose, the transparent element 3 is formed such that its lower surface 31 is in contact with the upper side 20 of the display panel 2, thereby completely filling the space between the display panel 2 and the curved upper side 30 with the material of the transparent element 3. The light L emitted by the display panel 2 is reflected towards the user 6 through the transparent plate 4, in this case the car's windshield 82. The user 6 views a virtual image VI, the virtual depth of which is provided by the distance from the windshield 82 to the display panel 2.

[0027] Figure 2 shows a schematic diagram of a second exemplary embodiment of the display device 1 according to the present invention. In this exemplary embodiment, the display device 1 has a curved display panel 2 and a curved backlight 5 that conforms to it. The curvature of the display panel 2 allows for a very thin design of the transparent element 3. This reduces the overall weight of the system.

[0028] Figure 3 shows a schematic diagram of a third exemplary embodiment of the display device 1 according to the present invention. The exemplary embodiment substantially corresponds to the exemplary embodiment of Figure 1, except that a planar display panel 2 is installed and positioned obliquely with respect to the viewing direction D. This allows the curvature of the transparent element 3 to be reflected across the surface of the display panel 2. In this way, less material is required to manufacture the transparent element 3, which is advantageous in terms of material cost and the weight of the overall system.

[0029] Figure 4 shows a schematic diagram of a fourth exemplary embodiment of the display device 1 according to the present invention. The exemplary embodiment substantially corresponds to the exemplary embodiment of Figure 2, except that the transparent plate 4, here in the case of the front glass 82, has a blackened region 40. Some image components of the display area of ​​the display panel 2 are then reflected through the blackened region 40 of the plate 4, and other image components are reflected through the transparent region of the plate 4. The arrangement of the light trap LT can be individually selected according to the desired implementation form of the entire system.

[0030] Figure 5 shows a schematic diagram of a first exemplary embodiment of the backlight 5. In this exemplary embodiment, the backlight indicated by the arrow is perpendicular to the surface of the display panel. A second exemplary embodiment of the backlight 5 is schematically shown in Figure 6. In this exemplary embodiment, the backlight indicated by the arrow is parallel to the viewing direction. In this case, the display panel may be positioned perpendicular to the viewing direction, or alternatively, at an angle. Light shaping by the backlight 5 allows the light L emitted by the backlight 5 to illuminate the head positions of one or more users. For example, the light L for backlighting a display panel may be shaped to illuminate the head position of the driver of a car, or to illuminate a narrow cone of light from the driver's head position to the head positions of the front-seat occupants.

[0031] Figure 7 shows a schematic diagram of a transport means 80 utilizing a display device 1 according to the present invention. In this example, the transport means 80 is an automobile. The automobile has a display device 1 according to the present invention, which in this example is presented in the form of a scenic view display and is located on the dashboard 81 below the windshield 82. The display device 1 may be used, for example, to display instructions from a navigation system 83. A data transfer unit 84 may be used to set up a connection to a backend, for example, to obtain updated software for components of the automobile. A memory 85 exists for storing data. Data is exchanged between various components of the automobile via a network 86. [Explanation of Symbols]

[0032] 1 Display device 2 Display Panels 20 Top of the display panel 3. Transparent elements 30 transparent elements top surface 31. Underside of transparent element 4 Transparent plate 40 Blackened areas 5. Backlight 6 users 7 Light-absorbing wall 80 Means of transportation 81 Instrument Panel 82 Windshield 83 Navigation System 84 Data Transfer Units 85 memory 86 Network L light LF Light Trap R (Viewing direction) SL Interferometry VB Virtual Image

Claims

1. Display device (1), Display panel (2), and The display panel (2) has a transparent element (3) positioned on the upper side (20), The display device (1) wherein the material of the transparent element (3) is selected such that there is no abrupt change in refractive index during the transition from the display panel (2) to the transparent element (3), and the transparent element (3) has a curved upper surface (30) designed to deflect incident interference light (IL) in the direction of the light trap (LT).

2. The display device (1) according to claim 1, wherein the display panel (2) is designed to be planar.

3. The display device (1) according to claim 2, wherein the display panel (2) is arranged diagonally with respect to the viewing direction (D).

4. The display device (1) according to claim 1, wherein the display panel (2) is designed to be curved.

5. A display device (1) according to any one of the prior claims, having a transparent plate (4) for reflecting the image displayed by the display panel (2) toward the user (6).

6. The display device (1) according to claim 5, wherein the transparent plate (4) has a blackened region (40).

7. A display device (1) according to any one of the prior claims, having a backlight (5), and designed so that light (L) emitted from the backlight (5) illuminates the head position of one or more users (6).

8. The display device (1) according to any one of the prior claims, wherein the light trap (LT) is designed as a light-absorbing wall (7).

9. The display device (1) according to any one of the prior claims, wherein the display device (1) forms a display strip either by itself or in combination with a further display device (1).

10. The display device (1) according to claim 9, wherein the optical shaping in the display strip is implemented such that, in at least a portion of the display strip, the image content is permanently and / or switchably visible to only one of a plurality of user positions.

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