Display device, especially for a vehicle, for displaying information with switchable sharing and private modes

Description

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

[0002] In recent years, the number and size of displays in vehicles have steadily increased. Modern designs include displays that extend across the entire width of the instrument panel. There are also design proposals where separate displays are located on both the driver's and passenger's side.

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

[0004] From US patent A-2020 / 0319512, a display device is known in which the light exiting the display surface is either diffused or collimated when viewed across the entire display surface. The backlighting 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, with collimated light emission, these areas are essentially no longer visible from a point located next to the display surface.

[0005] WO-A-2018 / 185476 describes a lighting system for a display device which has a large number of catadioptric elements.

[0006] A touchscreen with the capability of operating in a private mode is described in US-B-11 187 945.

[0007] Finally, US-A-2018 / 0082068 shows a display device with a dynamic private mode filter.

[0008] The object of the invention is to create a display device, in particular for a vehicle, with which it is possible to selectively minimize the visibility of displayed information when viewing the display device or an area of ​​the display device from the side, in particular from the driver's side.

[0009] To solve this problem, the invention proposes a display device, particularly for a vehicle, for displaying information, wherein the display device is provided with an electronic display with a front having a display area and a back facing away from the front, a backlighting unit for illuminating the display having a light-emitting side facing the back of the display, an optoelectronic panel arranged between the display and the backlighting unit, wherein the optoelectronic panel has at least two or more than two independently operable areas either in a private mode or in a split mode,in which light incident from the backlighting unit, for the visibility of the information displayed on the display area in private mode, is collimated and directed to regions of the display aligned with these areas, and, for the visibility of the information displayed on the display area in split mode, is diffused and directed to regions of the display aligned with these areas, and an electronic control unit for controlling both the optoelectronic panel for operating areas in private mode or split mode, and the display and the backlighting unit.

[0010] The concept according to the invention primarily uses an optoelectronic panel arranged between the electronic display of the display device and its backlighting unit. With the aid of this optoelectronic panel, it is possible to direct light incident from the backlighting unit to the display in independently controllable and therefore differently operable areas, either in a focused beam (referred to above and below as "collimated") or in a diffused beam. Regions of the display to which backlighting light is collimated make the displayed information clearly visible over a viewing angle that is narrower than the viewing angle that results when the region of the display is backlit with diffused light from the backlighting unit.As an example of an optoelectronic panel used according to the invention, reference is made to the known concepts based on liquid crystal cells. Backlighting regions of the display with focused light corresponds to operating the display device or regions of the display in private mode, whereas operation in split mode occurs when the display is backlit with diffused light.

[0011] According to the invention, the display area can be operated locally, i.e., for specific zones or regions, in split mode or private mode. This is achieved using an optoelectronic panel, or more generally, a layer using, for example, liquid crystal (LC) technology, which allows the light passing through the panel to be collimated or scattered by electrically controlling specific areas of the panel. The layer or optoelectronic panel is divided into individual "pixels" that can be controlled individually, with one or more pixels forming independently controllable areas.

[0012] The electro-optic panel can be designed, in particular, as described by way of example in DE-A-10 2020 100 709. According to this design, the electro-optic panel has a first polarizer, a second polarizer, a first liquid crystal layer, a first alignment layer, and a second alignment layer. The first and second polarizers are arranged one behind the other along the optical axis of the light. The first liquid crystal layer is located between the first and second polarizers. The first alignment layer is located between the first polarizer and the first liquid crystal layer, while the second alignment layer is located between the second polarizer and the first liquid crystal layer. The alignment direction of the first alignment layer is perpendicular to the alignment direction of the second alignment layer.

[0013] Alternatively, two of the aforementioned "optical stacks" can be arranged one behind the other and together form the optical panel of the display device according to the invention.

[0014] For further details of the exemplary optical panel design described above, according to the two variants, reference is made to DE-A-10 2020 100 790 (see in particular the Fign. 1 and 6 with associated description).

[0015] In a further advantageous embodiment of the invention, the backlighting unit may have a plurality of light sources, at least one or a group of light sources of which is assigned to each of the independently controllable areas of the optoelectronic panel, and the at least one light source or the light sources of each group assigned to an area of ​​the optoelectronic panel to be operated in private mode may be dimmed by means of the control unit. In this embodiment of the invention, the visibility of information displayed on the display device is further reduced by locally dimming the backlighting. This is achieved, for example, by using a backlighting unit comprising a plurality of light sources, each light source having one or more lamps and a reflector.The light sources are preferably LEDs. In those regions of the display where the corresponding light sources are dimmed, the information on the display device is shown with correspondingly less brightness. In this respect, the backlighting of the entire display is modulated with regard to its brightness level. This occurs when selected areas of the optoelectronic panel are operating in privacy mode. The control unit then coordinates the optoelectronic panel and the backlighting unit accordingly.

[0016] In a further advantageous embodiment of the invention, the backlighting unit can be provided with a light guide and / or an optical film and / or a diffusion film, as well as light sources that are arranged on the back side of the light guide and / or the optical film and / or the diffusion film facing away from the optoelectronic panel, or arranged at a distance and facing it. The light sources can be, for example, LEDs and reflectors. When using a light guide and / or an optical film and / or a diffusion film with the light sources arranged on their respective back sides (so-called Direct Backlight Unit), it may be necessary to homogenize the emitted light by applying shading or incorporating structures into the light-emitting side to avoid bright light spots on the light-emitting side.Examples of such measures are described in DE 10 2020 131 013 A1 and US 8 388 159 B2.

[0017] As described above, a feature of the invention is that those regions of the display intended for private mode can be selected or even chosen. This includes a variant in which the individual regions are predetermined, but also variants in which the regions can be selected at will by the operator, for example by entering parameters defining the individual regions or, in the case of a display device with touch sensors, by tapping or by marking regions by moving an object on the display surface.

[0018] The display device according to the invention can, if required, be additionally equipped with features that include a backlighting unit providing an asymmetrical light distribution. The asymmetrical light distribution may not be adjustable in the sense that it can be made "symmetrical." Thus, the luminance in the area that is less light-intensive in private mode is generally low. In split mode, the light intensity of the light sources can then be increased to provide backlighting of the display that is particularly sufficient for the requirements of automotive applications.

[0019] The invention is explained in more detail below with reference to an exemplary embodiment and the drawing. Specifically, the drawing shows: Fig. 1 a view from the rear and from above of the front interior of a vehicle, Fig. 2 a schematic representation of the switching option of individual areas of the display between "focused light transmission" and "diffused light transmission", Fig. 3 light distribution curves in split mode (dashed curve) and in private mode (solid curve), Fig. 4 a schematic representation of the situation in which the visibility of individual areas (segments) of the display area is more restricted for the driver than for the front passenger, and Fig. 5 different scenarios for selecting areas of the display area for operation in split mode or for the simultaneous operation of areas in private mode and other areas in split mode.

[0020] Privacy screen features for displays have existed for several years, particularly in the consumer market. In the simplest implementations, a static privacy effect is achieved by reducing the viewing angle of the display, for example, through the use of light control films.

[0021] Another approach is to dynamically activate and deactivate privacy screens, for example, by using a dual backlighting system. In split mode, a "normal" viewing experience is possible thanks to wide-angle illumination, while in privacy mode, a more collimated or focused light emission is used. This way, only viewers located in the direction of the collimated light can comfortably see the content.

[0022] However, these approaches often still exhibit a certain degree of luminance even outside the intended viewing angle. Due to the human eye's ability to adapt to low light conditions, this results in some residual visibility of the image and thus inadequate privacy protection, especially in dark ambient light.

[0023] A preferred application of the invention lies in the automotive sector. Fig. 1 The image shows a rear view of the front part of a vehicle interior. An LCD display (10) is located on the passenger side. Individual areas on this display can be selectively operated in shared mode or private mode. Modern vehicles sometimes feature "door-to-door" displays. In this case, the display area opposite the passenger would be the one where different areas could be operated in private mode and shared mode.

[0024] According to the invention, a direct backlighting system is combined with a segmented, optoelectronic privacy screen panel, so that the privacy effect can be activated independently in discrete areas of the display 10. The Fig. 2 The schematically represented display 10 features a direct-lit backlighting unit 12, an optical film 14 for increasing efficiency, and privacy cells based on polymer-dispersed liquid crystals (PDLC) for "shaping" the emitted light, as an example of an optoelectronic panel 16, wherein the privacy cells (in Fig. 2 (as indicated at 18) can be fully or only in selected areas controlled, as well as a liquid crystal display module 20 (LCD), on whose display surface a touch panel or a cover glass (both not shown) may be arranged.

[0025] In display areas used in privacy mode, the emitted light (see the arrows on the left in Fig. 1 ) compared to areas in split mode (see the arrows to the right).

[0026] At viewing angles where the privacy effect comes into play, e.g., from the driver's position in a vehicle, the parts of the display that are still in split-screen mode remain clearly visible, thus preventing the eye from fully adapting to the dark state. This reduces the visibility of the segments in privacy mode from the driver's perspective, which increases the subjective privacy effect and reduces distraction while driving. Fig. 3 ).

[0027] By using direct backlighting (see in Fig. 2 In addition to the light sources 22 (with optionally the reflectors 24), which can be dimmed locally, a second factor can be used to improve the privacy function of the display: The display areas with activated privacy mode can be selectively dimmed so that they are even less visible from the driver's point of view.

[0028] An electronic control unit 26, which controls the optoelectronic panel 16 or its individual privacy screen cells for operation either in private mode or in shared mode (selectively for each privacy screen cell), also ensures the dimming of the individual light sources 22 in this case, as in Fig. 2 shown.

[0029] Fig. 3 This diagram illustrates the visibility of display areas from different positions in the vehicle: Areas in split mode (shown with a low pixel density) exhibit high light density across the entire viewing angle, resulting in good visibility for both the driver and front passenger. Display areas in privacy mode (shown with a higher pixel density) also have good light density for the front passenger, but very low light density in the driver's position, making them difficult or impossible to read from the driver's seat. Because certain areas of the display remain clearly visible to the driver, their eyes cannot fully adjust to the less visible areas operating in privacy mode. This further enhances the privacy protection.

[0030] Furthermore, new use cases arise when only parts of the display are in private mode ( Fig. 4 When using the display for menu navigation, all parts can be visible ( Fig. 5a )). Controls such as the temperature control can remain visible to all vehicle occupants ( Fig. 5b ), areas 1 and 2), while dynamic content such as movies or web activities can be displayed in areas 3 and 4 of the display with a privacy function for the driver. This also applies during menu navigation ( Fig. 5c ), areas 1 and 4) notifications can be displayed in parts of the display (areas 2 and 3) in private mode to avoid distracting the driver and to ensure the confidentiality of the messages.

[0031] The number of segments can be further increased by controlling the segments with a passive or active matrix that corresponds to the number of local dimming zones provided by the direct backlighting.

[0032] According to the invention, the switching between the two modes occurs pixel by pixel. Each individual pixel can therefore be switched. The switchable areas on the display are thus freely controllable and selectable. Essentially, there are as many switchable segments as there are pixels on the display.

[0033] The concept according to the invention can also be combined with other switchable or stationary privacy concepts. Examples can be found in German patent application 10 2021 126 024.8 dated October 7, 2021, or in the German patent application entitled "Display device, in particular for a vehicle, with switchable split and private mode" (Attorney's mark: 212844DE; filed on the same day as the present patent application), or in German patent application 10 2021 126 025.6 dated October 7, 2021, or in the German patent application entitled "Display device, in particular for a vehicle, for displaying information with asymmetric backlighting" (Attorney's mark: 212845DE; filed on the same day as the present patent application).

[0034] The subject matter of the aforementioned patent applications is hereby defined by reference to the content of the present patent application.

[0035] In displays with a switchable privacy function for toggling between split-screen mode and private mode, as provided for in the invention, this can be done both manually and automatically. In automotive applications, automatic switching from split-screen mode to private mode is advantageous when, for example, a camera monitoring the driver detects that the driver is looking towards the passenger display or passenger display area (eye tracking). In such cases, it would also be useful to automatically switch to private mode when "moving images" are displayed on the passenger display or passenger display area. Thus, various approaches exist for the automatic switching from split-screen mode to private mode. Accordingly, resetting to split-screen mode also occurs automatically.The automatic switch to private mode can be omitted in vehicles with seat occupancy detection if no passenger seat occupancy is detected. BEZUGSZEICHENLISTE

[0036] 10 Display 12 Backlight unit 14 Optical film 16 Optoelectronic panel 18 Optoelectronic panel privacy cells 20 LCD display 22 Light sources 24 Reflectors 26 Control unit

Claims

1. A display device, in particular for a vehicle, for displaying information, comprising - an electronic display (10) having pixels, comprising a front side having a display surface, and a rear side facing away from the front side, - a backlighting unit (12) for backlighting the display (10), which has a light output side arranged so as to face the rear side of the display (10), - an optoelectronic panel (16) which is arranged between the display (10) and the backlighting unit (12), wherein the optoelectronic panel (16) comprises at least two or more than two areas adapted to be operated independently either in a private mode or in a sharing mode, in which modes light impinging from the backlighting unit (12) is transmittable in a bundled manner to regions of the display (10), each flush with these areas, for the visibility of information displayed on the display surface, when operated in the private mode, and is transmittable in a scattered manner to regions of the display (10), each flush with these areas, for the visibility of information displayed on the display surface, when operated in the sharing mode, and - an electronic control unit (26) for controlling both the optoelectronic panel (16) for operating areas in the private mode or in the sharing mode, as well as the display (10) and the backlighting unit (12), characterized in that switching between the two modes takes place independently of one another for each display pixel.

2. The display device according to claim 1, characterized in that the backlighting unit (12) has a light guide and / or an optical film and / or a diffusion foil as well as light sources (22) which are arranged in particular distributed in a matrix shape, which is arranged on the rear side of the optical fiber facing away from the optoelectronic panel (16), or is arranged on the rear side of the optical film facing away from the optical panel (16), or is arranged on the rear side of the diffusion foil facing away from the optical panel (16), or is arranged at a distance from one of the aforementioned rear sides and facing this respective rear side.

3. The display device of claim 2, characterized in that the light sources (22) comprise illuminants, in particular LEDs, and reflectors.

4. The display device according to one of claims 1 to 3, characterized in that the backlighting unit (12) comprises a plurality of light sources (22), at least one of which is assigned to a respective other of the independently operable areas of the optoelectronic panel (16), and in that the at least one light source (22) which is assigned to an area of the optoelectronic panel (16) to be operated in the private mode is dimmable by means of the control unit (26).

5. The display device according to one of claims 1 to 4, characterized in that the regions on the display surface can be selected manually for the visibility of the information displayed there in the private mode or in the sharing mode.

6. The display device according to claim 5, characterized in that a touch sensor system is assigned to the display surface and that the regions on the display surface can be selected by being marked through a touch operation.