Display device with stray light suppression

Abstract

The invention relates to a display device (1) with stray light suppression. A display device (1) has a display panel (2) and a transparent element (3) arranged on an upper side (20) of the display panel (2). The material of the transparent element (3) is selected such that there is no refractive index mutation in the transition from the display panel (2) to the transparent element (3). The transparent element (3) has a curved upper side (30) which is designed to deflect incident stray light (SL) in the direction of the light trap (LF).

Description

Technical Field

[0001] This invention relates to a display device with stray light / interference light suppression. Background Technology

[0002] The number and size of display devices in transportation vehicles are constantly increasing. Display devices, such as those used as instrument clusters for drivers, central displays, and passenger displays, are available on the market.

[0003] Head-up displays (HUDs) are becoming increasingly common in transportation vehicles. A HUD is understood as a display system in which an observer can maintain their viewing direction by overlaying the content onto their field of vision. Initially used primarily in the aviation sector due to their complexity and cost, these systems are now being widely installed in the automotive industry.

[0004] Head-up displays (HUDs) typically consist of an imaging unit or PGU (Picture Generating Unit), an optical unit, and a mirror unit. The imaging unit generates an image using at least one display element. Most modern HUDs use LCD-based displays (LCD stands for Liquid Crystal Display) to generate images. The optical unit directs the image onto the mirror unit. The mirror unit is a partially reflective, light-transmitting glass. Therefore, the observer sees the content displayed as a virtual image by the imaging unit and simultaneously sees the real world behind the glass. In the automotive field, the windshield is often used as the mirror unit, and its curved shape must be taken into account during display. Through the combined action of the optical and mirror units, the virtual image is a magnified display of the image generated by the imaging unit.

[0005] In an alternative implementation, the display is arranged relative to the windshield such that the view of the display is provided through the windshield, and virtual depth is given directly by the distance to the windshield. Such a display is called a scenic-view display. Currently, the image content of a scenic-view display is mirrored through a tinted area of ​​the windshield to prevent direct sunlight or other light sources from hitting the display. If this tinted area were not present in the windshield, sunlight or external light could reach the display directly and superimpose onto the image content as retroreflection or backscattering. This could distract or irritate the driver, which must be avoided.

[0006] Against this backdrop, DE 10 2010 032 998 A1 describes a head-up display for a motor vehicle, the head-up display having a projection device by which an image to be displayed is projected onto the windshield of the motor vehicle, which serves as a combination device. The projection device has a translucent cover pointing towards the windshield, the translucent cover being configured to reflect external light incident on the cover onto an absorbing surface. The absorbing surface is at least partially formed by an inner coating of the windshield.

[0007] WO 2019 / 238849 A1 describes an instrument for generating a virtual image with stray light suppression. The instrument includes a light source, a display element for generating the image, and an anti-glare element. The anti-glare element has a curved surface. Summary of the Invention

[0008] The purpose of this invention is to provide an improved display device with stray light suppression.

[0009] This objective is achieved by a display device having the features of claim 1. The preferred embodiments of the invention are the subject of the dependent claims.

[0010] According to a first aspect of the invention, a display device has a display panel and a transparent element disposed on the upper side of 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, which is designed to deflect incident stray light toward a light trap.

[0011] In the solution according to the invention, the display panel is placed below a cover whose surface is curved such that incident light is appropriately deflected. This surface satisfies the requirements for geometric anti-reflection. Furthermore, the material of the cover is chosen such that there is no abrupt change in refractive index from the outer surface to the display panel. The cover is formed such that the space between the display panel and the curved surface is completely filled with the material of the cover. In this way, intrusive back reflections are avoided. The display device can, for example, be mounted in a tank such that incident stray light is deflected into the tank wall, which serves as a light trap.

[0012] According to one aspect of the invention, the display panel is implemented as a planar surface. In this way, a display device can be implemented using commercially available display panels, which is advantageous in terms of manufacturing costs.

[0013] According to one aspect of the invention, the display panel is arranged at an angle relative to the viewing direction. This allows for the bending of the transparent element through the surface of the display panel. In this way, the amount of material required to produce the transparent element is reduced, thus offering advantages in terms of material cost and overall system weight.

[0014] According to one aspect of the invention, the display panel is implemented as a curved shape. In this embodiment, a specially shaped display panel is required. However, in contrast, the transparent element can be implemented very thinly, thereby reducing the weight of the entire system.

[0015] According to one aspect of the invention, the display device has a transparent glass designed to reflect an image displayed by the display panel toward the observer. A scenic view display can be realized using transparent glass (e.g., a windshield of a motor vehicle).

[0016] According to one aspect of the invention, the transparent glass has a blackened area. Then, some image portions of the display area of ​​the display panel are reflected through the blackened area of ​​the glass, while other image portions are reflected through the transparent area of ​​the glass. The position of the light trap can be individually selected according to the desired implementation of the entire system.

[0017] According to one aspect of the invention, the display device has a backlight portion designed such that light emitted from the backlight portion illuminates the head position of one or more observers. For example, the light for the backlight portion of the display panel can be shaped to illuminate the head position of a motor vehicle driver, or to illuminate a narrow cone of light from the driver's head position to the passenger's head position.

[0018] According to one aspect of the invention, the optical trap is designed as a light-absorbing wall. This ensures that no stray light reflections are emitted from the optical trap.

[0019] According to one aspect of the invention, a display device forms a display strip, either alone or in combination with other display devices. In such a display strip, the width of the shared display area is significantly greater than the height of the display area. As a design option for the display strip, for example, a display can be implemented that extends over the entire width or at least almost the entire width of a vehicle's dashboard.

[0020] According to one aspect of the invention, light shaping in the display strip is implemented such that, for at least a portion of the display strip, image content is permanently and / or switchably visible only to one of a plurality of viewing positions. For example, light shaping can be implemented such that specific image content is visible only to the driver of a motor vehicle or only to the front passenger. On the one hand, this can be permanent, but it is equally possible that the visibility of the image content can be switched individually when needed. Furthermore, light shaping allows switching between an operating mode with unrestricted visibility (Public Mode) and an operating mode with limited visibility (Privacy Mode), meaning the entire system can be designed as a switchable privacy display.

[0021] Preferably, the display device according to the invention is used in a means of transportation. This means of transportation may be, for example, a motor vehicle; however, alternatively, it may be an aircraft, rail vehicle, or ship. Here, the application of the solution according to the invention can be particularly considered for all display systems that require or wish to suppress stray light, and for head-up display systems. However, the display device according to the invention can also be used in cinemas, near-eye displays, or general multimedia applications.

[0022] Other features of the invention will become apparent from the following description and appended claims in conjunction with the accompanying drawings. Attached Figure Description

[0023] Figure 1 A first embodiment of the display device according to the present invention is illustrated schematically;

[0024] Figure 2 A second embodiment of the display device according to the present invention is illustrated schematically;

[0025] Figure 3 A third embodiment of the display device according to the present invention is illustrated schematically;

[0026] Figure 4 A fourth embodiment of the display device according to the present invention is illustrated schematically;

[0027] Figure 5 A first embodiment of the backlight section is schematically shown;

[0028] Figure 6 A second embodiment of the backlight is schematically shown; and

[0029] Figure 7 A vehicle using a display device according to the present invention is illustrated schematically. Detailed Implementation

[0030] To better understand the principles of the present invention, embodiments thereof are described in more detail below with the aid of the accompanying drawings. In the drawings, the same reference numerals denote the same or equivalent elements, and they are not necessarily described again in every drawing. It should be understood that the present invention is not limited to the embodiments shown, and the described features may be combined or modified without departing from the scope of protection defined in the appended claims.

[0031] Figure 1 A first embodiment of a display device 1 according to the present invention is schematically shown. The display device 1 has a display panel 2 and a transparent element 3 arranged on the upper side 20 of the display panel 2. The transparent element 3 has a curved upper side 30, which is designed to deflect incident stray light SL toward a light trap LF. The light trap LF can be, for example, formed by a light-absorbing wall 7 of a groove into which the display device 1 or the display panel 2 and the transparent element 3 are mounted. Figure 1 In the middle, only the light-absorbing wall 7 is shown instead of such a trough.

[0032] The material of the transparent element 3 is chosen such that there is no abrupt change in refractive index during the transition from the display panel 2 to the transparent element 3. The transparent element 3 is therefore shaped such that its lower side 31 rests on the upper side 20 of the display panel 2, and thus the space between the display panel 2 and the curved upper side 30 is completely filled with the material of the transparent element 3. Light L emitted from the display panel 2 is reflected towards the observer 6 via the transparent glass 4 (in this case, the windshield 82 of a motor vehicle). The observer 6 sees a virtual image VB, the virtual depth of which is given by the distance between the display panel 2 and the windshield 82.

[0033] Figure 2 A second embodiment of the display device 1 according to the present invention is schematically shown. In this embodiment, the display device 1 has a curved display panel 2 and a curved backlight portion 5 that matches the display panel. Due to the curvature of the display panel 2, the transparent element 3 can be implemented very thinly. This results in a reduction in the weight of the entire system.

[0034] Figure 3 A third embodiment of the display device 1 according to the present invention is schematically shown. This embodiment is largely similar to... Figure 1 Corresponding to the previous embodiment, but with a flat display panel 2 that is arranged at an angle relative to the viewing direction R. This allows the bending of the transparent element 3 to be transmitted through the surface of the display panel 2. In this way, the material required to manufacture the transparent element 3 is reduced, thus offering advantages in terms of material cost and overall system weight.

[0035] Figure 4A fourth embodiment of the display device 1 according to the present invention is schematically shown. This embodiment is largely similar to... Figure 2 Corresponding to the embodiment, but the transparent windshield 4 (here, windshield 82) has a blackened area 40. Thus, some image portions of the display area of ​​the display panel 2 are reflected through the blackened area 40 of the glass 4, while other image portions are reflected through the transparent area of ​​the glass 4. The placement of the LF light trap can be individually selected according to the desired implementation of the entire system.

[0036] Figure 5 A first embodiment of the backlight unit 5 is schematically shown. In this embodiment, the backlight unit, indicated by the arrow, is perpendicular to the surface of the display panel. Figure 6 The diagram schematically illustrates a second embodiment of the backlight portion 5. In this embodiment, the backlight portion, indicated by the arrow, is parallel to the viewing direction. Here, the display panel can be arranged perpendicular to the viewing direction or alternatively tilted to the viewing direction. The light shaping of the backlight portion 5 can illuminate the head positions of one or more observers with the light L emitted by the backlight portion 5. For example, the light L for the backlight portion of the display panel can be shaped to illuminate the head position of the driver of a motor vehicle, or to illuminate a narrow cone of light from the driver's head position to the passenger's head position.

[0037] Figure 7 A vehicle 80 using a display device 1 according to the invention is schematically shown. In this example, the vehicle 80 is a motor vehicle. The motor vehicle has a display device 1 according to the invention, which in the illustrated example takes the form of a landscape view display arranged in a dashboard 81 below the windshield 82. The display device 1 can be used, for example, to display instructions of a navigation system 83. A connection to a backend can be established, for example, by means of a data transmission unit 84, to obtain, for example, updated software for components of the motor vehicle. A memory 85 is provided for storing data. Data exchange between the various components of the motor vehicle is carried out via a network 86.

[0038] List of reference numerals in the attached diagram:

[0039] 1 Display device

[0040] 2 Display Panels

[0041] 20 The upper side of the display panel

[0042] 3 transparent elements

[0043] The top side of 30 transparent elements

[0044] 31. The bottom side of the transparent element

[0045] 4 transparent glass

[0046] 40 Blackened areas

[0047] 5 Backlight section

[0048] 6 observers

[0049] 7 Light-absorbing walls

[0050] 80 vehicles

[0051] 81 Dashboard

[0052] 82 windshield

[0053] 83 Navigation System

[0054] 84 data transmission units

[0055] 85 memory

[0056] 86 Network

[0057] L-light

[0058] LF optical trap

[0059] R observation direction

[0060] SL stray light

[0061] VB virtual image.

Claims

1. A display device (1), the display device comprising: - Display panel (2); and - A transparent element (3) arranged on the upper side (20) of the display panel (2); in, 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), wherein the transparent element (3) has a curved upper side (30) designed to deflect incident stray light (SL) toward the light trap (LF).

2. The display device (1) according to claim 1, characterized in that, The display panel (2) is implemented as a flat surface.

3. The display device (1) according to claim 2, characterized in that, The display panel (2) is arranged at an angle relative to the viewing direction (R).

4. The display device (1) according to claim 1, characterized in that, The display panel (2) is implemented as a curved shape.

5. The display device (1) according to any one of the preceding claims, characterized in that, The display device has a transparent glass (4) for reflecting the image displayed by the display panel (2) toward the observer (6).

6. The display device (1) according to claim 5, characterized in that, The transparent glass (4) has a blackened area (40).

7. The display device (1) according to any one of the preceding claims, characterized in that, The display device has a backlight (5) that is designed such that light (L) emitted from the backlight (5) illuminates the head position of one or more observers (6).

8. The display device (1) according to any one of the preceding claims, characterized in that, The light trap (LF) is designed as a light-absorbing wall (7).

9. The display device (1) according to any one of the preceding claims, characterized in that, The display device (1) forms a display strip either alone or in combination with other display devices (1).

10. The display device (1) according to claim 9, characterized in that, The light shaping in the display strip is achieved in such a way that, for at least a portion of the display strip, the image content is permanently and / or switchably visible only to one of a plurality of viewing positions.

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