Display device, in particular for a vehicle, for displaying information, with switchable sharing and personal modes

Abstract

The invention relates to a display device, in particular for a vehicle, for displaying information, comprising an electronic display (10) having a front surface with a display surface and a rear surface facing away from the front surface, and comprising a backlight unit (12) for backlighting the display (10), the backlight unit has a light output face arranged to face a rear surface of the display (10). The display device further has an optoelectronic panel (16) arranged between the display (10) and the backlight unit (12), the optoelectronic panel (16) having a plurality of regions which can be operated independently of one another and in which the light from the backlight unit (12) can be relayed in a bundled manner to a region of the display (10) flush with the region, the display (10) is coupled to the display surface in order to make information displayed on the display surface visible during operation in a private mode and to a region of the display (10) flush with said region in a scattered manner in order to make information displayed on the display surface visible during operation in a shared mode. The display device further comprises an electronic control unit (26) for actuating the optoelectronic panel (16) and the display and backlight unit (12) for operating the area in a private mode or a shared mode.

Description

Technical Field

[0001] The invention relates to a display device, in particular a display device for a vehicle, for displaying information in a private mode or a shared mode. Background Art

[0002] In recent years, the number of display devices in vehicles and their size have steadily increased. Modern concepts include display screens that extend over the entire width of the dashboard. Designs are also known in which separate display devices are arranged on the driver's side and the passenger's side.

[0003] For safety reasons, the vehicle driver should not be distracted by information displayed on the display device assigned to the driver or in the area of ​​the display device assigned to the passengers.

[0004] A display device is known from US-A-2020 / 0319512, in which the light leaving the display surface is scattered or emitted in a collimated manner when viewed over the entire display surface. The backlight unit of the known display device has individually controllable light sources that are dimmable. In this way, individual areas of the display surface can be darkened so that these areas are essentially no longer visible from points adjacent to the display surface when light is emitted in a collimated manner.

[0005] WO-A-2018 / 185476 describes an illumination system for a display device comprising a plurality of catadioptric elements.

[0006] US-B-11 187 945 describes a touch screen that can be operated in a private mode.

[0007] Finally, US-A-2018 / 0082068 shows a display device with a dynamic privacy mode filter. Summary of the invention

[0008] The object of the invention is to create a display device, in particular for a vehicle, with which the visibility of the displayed information can be selectively minimized when the display device or a region of the display device is viewed from the side, in particular from the driver's side.

[0009] To achieve this object, the present invention provides a display device, particularly for a vehicle, for displaying information, the display device being provided with

[0010] - an electronic display having a front surface with a display surface and a rear surface facing away from the front surface,

[0011] a backlight unit for backlighting a display, the backlight unit having a light output face arranged facing a back surface of the display,

[0012] - an optoelectronic panel arranged between the display and the backlight unit, the optoelectronic panel comprising at least two or more areas adapted to be independently operated in a private mode or in a shared mode, the light incident from the backlight unit being transmittable in a bundled manner to each area of ​​the display flush with these areas when operated in the private mode for visibility of information displayed on the display surface, and in a dispersed manner to each area of ​​the display flush with these areas when operated in the shared mode,

[0013] - Electronic control unit for controlling the photoelectric panels as well as the display and backlight unit for operating the zone in private mode or shared mode.

[0014] The concept according to the invention mainly uses a photovoltaic panel arranged between an electronic display of a display device and its backlight unit. With the help of this photovoltaic panel, light incident from the backlight unit can be forwarded to displays that can be independently controllable in a bundled manner (referred to as "collimation" in this context) or in a decentralized manner, so that the operable areas are different. The display areas reached by the backlight collimation enable the displayed information to be clearly visible at a restricted viewing angle compared to the viewing angle obtained when the display area is backlit with diffuse light from the backlight unit. As an example of a photovoltaic panel used according to the invention, reference is made to the known concept based on liquid crystal cells. The backlight area of ​​the display with bundled light corresponds to the operation of the display device or an area of ​​the display in private mode, while the operation in shared mode is achieved when the display is backlit with diffuse light.

[0015] Thus, according to the invention, it is possible to operate the display surface locally in a specific area or region, in a shared mode or in a private mode. For this purpose, an optoelectronic panel is used, or more generally, a layer in liquid crystal (LC) technology, which can collimate or scatter the light that passes through it by means of an area of ​​the electrically controlled panel. For this purpose, the layer or optoelectronic panel is divided into individual "pixels" that can be controlled individually, wherein one pixel or several pixels form an area that can be controlled independently of each other.

[0016] The photovoltaic panel can be designed in particular as described in the example of DE-A-10 2020 100 709. Thus, the photovoltaic panel comprises a first polarizer, a second polarizer, a first liquid crystal layer, a first orientation layer and a second orientation layer. The first polarizer and the second polarizer are arranged front and back along the optical axis of the light. The first liquid crystal layer is located between the first polarizer and the second polarizer. The first orientation layer is located between the first polarizer and the first liquid crystal layer, and the second orientation layer is located between the second polarizer and the first liquid crystal layer. The orientation direction of the first orientation layer is perpendicular to the alignment direction of the second orientation layer.

[0017] As an alternative, the two “optical stacks” described above can be arranged one after the other and together form an optoelectronic panel of a display device according to the invention.

[0018] For further details on the above exemplary structures of photovoltaic panels according to two variants, reference is made to DE-A-10 2020 100 790 (see in particular Figure 1 and Figure 6 and related description), the contents of which are incorporated by reference into the subject matter of this PCT application.

[0019] In an advantageous refinement of the invention, it can be provided that the backlight unit has a plurality of light sources, wherein in each case at least one or a group of light sources is assigned to different areas of the independently controllable areas of the optoelectronic panel, and at least one light source or a corresponding group of light sources assigned to the optoelectronic panel area to be operated in private mode can be dimmed by a control unit. In a further development of the invention, the visibility of the information displayed on the display device is further reduced by local dimming of the backlight. This is achieved, for example, by using a backlight unit comprising a large number of light sources, each having one or more illuminants and a reflector. The light sources are preferably LEDs. In those areas of the display where the relevant light sources are dimmed, the information on the display device is correspondingly illuminated less. Thus, the backlight of the entire display is modulated in terms of brightness. This occurs when a selected area of ​​the optoelectronic panel is operated in private mode. Thus, the control unit controls the optoelectronic panel and the backlight unit in a manner that corresponds to one another.

[0020] In another advantageous embodiment of the invention, it can be provided that the backlight unit comprises a light guide and / or an optical film and / or a diffuser film and a light source, and is arranged on the back side of the light guide and / or the optical film and / or the diffuser film, facing away from the photovoltaic panel, or arranged at a position away from the photovoltaic panel and facing the photovoltaic panel. The light source may include a light emitter in the form of an LED, for example, and a reflector. When the light sources are arranged on their respective rear sides (so-called direct-lit backlight units), the use of a light guide and / or an optical film and / or a diffuser film may require uniform emission of light by applying a shading or bonding structure on the light emission side to avoid bright spots on the light emission side. Examples of such measures are described in DE 102020 131 013A1 and US 8 388 159 B2.

[0021] As mentioned above, one feature of the invention is that the areas of the display to be operated in private mode can be selected or even chosen. This includes variants in which the individual areas are predefined, but also variants in which the operator can select the areas at will, for example by entering parameters that define individual areas or, in the case of display devices with touch sensors, by marking areas by clicking or by moving an object on the display surface.

[0022] If desired, the display device according to the invention can additionally be equipped with the features of a backlight unit which ensures an asymmetrical light distribution. Possibly, the asymmetrical light distribution is not affected because it can be "symmetrized". This means that in private mode the brightness of areas with lower light intensity is generally lower. In shared mode, by increasing the light intensity of the light source, it can be ensured that the backlighting of the display is particularly adapted to the requirements of automotive applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below by means of exemplary embodiments and with reference to the accompanying drawings. Specifically, the accompanying drawings show:

[0024] Figure 1 This is a view of the front interior of the vehicle as viewed from the rear and top.

[0025] Figure 2 Schematic diagram of the display switching between "bundled light transmission" and "scattered light transmission" in various areas.

[0026] Figure 3 : are light distribution diagrams in shared mode (dashed line diagram) and private mode (solid line diagram),

[0027] Figure 4 A schematic diagram showing the situation where visibility of various areas (segments) of the surface is more limited for the driver than for the passengers, and

[0028] Figure 5 Various scenarios for selecting display surface areas to operate in shared mode or to simultaneously operate areas in private mode and other areas in shared mode.

[0029] Reference numerals

[0030] 10 Display

[0031] 12 Backlight unit

[0032] 14 Optical film

[0033] 16 Photovoltaic panels

[0034] 18 Privacy cells for photovoltaic panels

[0035] 20 LCD display

[0036] 22 Light Source

[0037] 24 Reflector

[0038] 26 Control Unit DETAILED DESCRIPTION

[0039] Privacy features on displays have been around for many years, especially in the consumer market. In the simplest implementation, a static privacy effect is achieved by reducing the viewing angle of the display, for example, by using a light control film.

[0040] Another approach is to dynamically activate and deactivate privacy protection, for example, by employing a dual backlight system. In shared mode, a "normal" viewing experience is achieved through wide-viewing angle lighting, while in private mode, a more collimated or focused light emission is used. This way, only viewers in the direction of the collimated light propagation can comfortably see the content.

[0041] However, these methods usually still have a certain brightness even outside the intended viewing angle. Due to the human eye's adaptation to low-light conditions, this can cause image retention visibility, resulting in insufficient privacy, especially in dark ambient lighting conditions.

[0042] A preferred application of the invention is in the automotive field. Figure 1 A view of the front of the vehicle interior from behind is shown. An LCD display 10 is provided on the passenger side. On this display, the individual zones can now be selectively operated in shared mode or in private mode. Modern vehicles sometimes have "door-to-door" displays. Here, the display area opposite the passenger would be the area where the different zones can be operated in private mode and in shared mode.

[0043] In accordance with the present invention, a direct backlight system is combined with a segmented optoelectronic privacy cell panel so that the privacy effects can be activated in discrete areas of the display 10 independently of each other. Figure 2 The display 10 schematically shown in FIG. 1 has a direct-lit backlight unit 12, an optical film 14 for improving efficiency, a privacy unit based on polymer dispersed liquid crystal (PDLC) as an example of an optoelectronic panel 16 for "shaping" the emitted light, wherein the privacy unit ( Figure 2 18 in the figure) can be controlled completely or only in selected areas, and a liquid crystal display module 20 (LCD), on the display surface of which a touch panel or cover glass (neither shown) can also be arranged.

[0044] In the display area used in private mode, the light emitted (see Figure 1 The arrow on the left in the figure) is more directional than the area in shared mode (see the arrow on the right).

[0045] At viewing angles where the privacy effect comes into play, such as the driver's position in the vehicle, the portion of the display that is in shared mode remains clearly visible, preventing the eyes from fully adapting to dark conditions. From the driver's perspective, this reduces the visibility of the private mode portion, improving subjective privacy performance and reducing distractions during vehicle operation ( Figure 3 ).

[0046] By using locally dimmable direct backlighting (see Figure 2 With a light source 22 with an optional reflector 24 in the display, a second factor can be used to improve the privacy function of the display: display areas with an activated privacy mode can be selectively dimmed, making them more difficult to see from the driver's perspective.

[0047] The electronic control unit 26 controls the photovoltaic panel 16 or its individual privacy units to operate in a private mode or a shared mode (selective for each privacy unit), in which case dimming of the individual light sources 22 is also ensured, such as Figure 2 shown.

[0048] Figure 3 The visibility of the display areas from different positions in the vehicle is shown: the area in shared mode (displayed with a low dot density) shows a high light density across the entire viewing angle, providing good visibility for the driver and front passenger. The display area in private mode (displayed with a higher dot density) also has good light density for the passengers, but the light density at the driver's position is very low, making it difficult or impossible to read from the driver's position. Because some areas of the display or its display area remain clearly visible to the driver, his eyes cannot fully adapt to the less visible areas operating in private mode. This further improves privacy protection performance.

[0049] Additionally, new apps appear when only certain parts of the display are in private mode ( Figure 4 When using the display to navigate the menu, all components are visible ( Figure 5 a). Controls such as temperature control are visible to all vehicle occupants ( Figure 5 b, zones 1 and 2), while dynamic content such as movies or web activities can be shown in zones 3 and 4 of the display and provide privacy for the driver. Even during menu navigation ( Figure 5 c, areas 1 and 4), notifications can also be shown in a partial area of ​​the display (areas 2 and 3) in private mode to avoid distracting the driver and ensure the confidentiality of the message.

[0050] The number of segments can be further increased by controlling the segments with a passive or active matrix corresponding to the number of local dimming zones provided by the direct backlight.

[0051] Basically, according to the invention, the switching between the two modes is performed pixel by pixel. Thus, one pixel can be switched at a time. Thus, the switchable area on the display can be controlled and selected as required. Basically, the number of switchable segments is as many as the number of pixels of the display.

[0052] The concept according to the invention can also be combined with other switchable or fixed privacy concepts. Examples of this can be found in the German patent application 10 2021 126 024.8 of October 7, 2021, or in the German patent application entitled "Display device with switchable shared mode and private mode, especially for vehicles" (attorney number: 212844DE; filed on the same day as the present patent application) or in the German patent application 10 2021 126025.6 of October 7, 2021 or in the German patent application entitled "Display device, especially for vehicles, for displaying information by means of asymmetric backlighting" (attorney number: 212845DE; filed on the same day as the present patent application).

[0053] The subject matter of the above-mentioned patent applications is hereby incorporated by reference into the content of the present patent application.

[0054] For displays with a switchable privacy function for switching between shared mode and private mode as provided by the present invention, this can be done both manually and automatically. In automotive applications, it is proposed to automatically switch from shared mode to private mode if a camera observing the driver detects that the driver is looking at the passenger display or the passenger display area (eye tracking). In this case, it is also possible to automatically switch to private mode when a "moving image" is displayed on the passenger display or the passenger display area. There are multiple ways to automatically switch from shared mode to private mode. Therefore, it is also automatically reset to shared mode. If no passenger seat occupancy is detected, the automatic switch to private mode can be omitted in vehicles with seat occupancy detection.

Claims

1. A display device, particularly for a vehicle, for displaying information, comprising - an electronic display (10) having a front surface and a rear surface facing away from the front surface, the front surface having a display surface, a backlight unit (12) for backlighting the display (10), the backlight unit having a light output surface arranged to face the rear surface of the display (10), - a photovoltaic panel (16) disposed between the display (10) and the backlight unit (12), the photovoltaic panel (16) comprising at least two or more areas operable independently of each other in a private mode or a shared mode, wherein: The photovoltaic panel (16) comprises at least two or more areas adapted to be independently operated in a private mode or a shared mode, and when operating in the private mode, light incident from the backlight unit (12) is transmittable in a bundled manner to each area of ​​the display (10) flush with these areas for visibility of information displayed on the display surface, and when operating in the shared mode, light incident from the backlight unit (12) is transmittable in a diffuse manner to each area of ​​the display (10) flush with these areas, and - An electronic control unit (26) for controlling the photovoltaic panel (16) as well as the display (10) and the backlight unit (12) for operating the zone in private mode or shared mode.

2. The display device according to claim 1, characterized in that The backlight unit (12) includes a light guide and / or an optical film and / or a diffuser film, and a light source (22) that is particularly distributed in a matrix form and is arranged on the rear side of the light guide and / or the optical film and / or the diffuser film, facing away from the photovoltaic panel (16), or is arranged at a distance from the photovoltaic panel and facing the photovoltaic panel.

3. The display device according to claim 2, characterized in that: The light source (22) comprises a light emitting body, in particular an LED, and a reflector.

4. The display device according to any one of claims 1 to 3, characterized in that: The backlight unit (12) comprises a plurality of light sources (22), wherein at least one of the plurality of light sources (22) is respectively assigned to another one of the independently operable areas of the photoelectric panel (16), and at least one light source (22) assigned to the area of ​​the photoelectric panel (16) operating in private mode can be dimmed by a control unit (26).

5. The display device according to any one of claims 1 to 4, characterized in that: The area on the display surface may be manually selected for visibility of information displayed therein in either the private mode or the shared mode.

6. The display device according to claim 5, characterized in that: A touch sensor system is assigned to the display area, and an area on the display surface is selected by a touch operation mark.

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