Display device with transparent screen element, motor vehicle

Abstract

The invention relates to a display device (10), comprising a transparent screen element (20) having a front side (20) and a rear side opposite the front side (20), and a polarization element (26) arranged on the rear side of the transparent screen element (20) in a plane, which is designed to attenuate light actively emitted by at least one light-emitting element of the transparent screen element (20). The invention also relates to a motor vehicle having such a display device (10), in particular wherein the display device (10) is arranged independently at or on an interior element (14) of the motor vehicle (12).

Description

Technical Field

[0001] This invention relates to a display device having a transparent screen element, i.e., having a component or transparent assembly designed and configured to display content on a transparent display surface. The transparent screen element is preferably designed as a transparent screen with organic light-emitting diodes (“TOLED”). Background Technology

[0002] Modern motor vehicles may be equipped with displays, such as those independently mounted on the dashboard. These transparent displays project light in two directions, for example, towards the driver and towards the windshield. When the display is switched to "transparent," the displayed content is visible not only on the front side (facing the driver) but also on the rear side (facing the windshield). Therefore, the content can be seen in a mirror image from outside the vehicle.

[0003] DE 102 38 531 A1 describes a display device having a display panel with active optical elements for generating images, the display device being arranged in a vehicle such that the driver can observe the driving route or operating elements in the vehicle through the display content.

[0004] A motor vehicle is known from DE 10 2014 014 412 A1, which has pixel elements capable of operating in a self-illuminating manner and a control device designed to display a graphical operating interface on a touch screen by means of the pixel elements in a first operating mode, and to control at least one device of the motor vehicle, different from the operating device, by means of a control signal based on touch signals from the touch screen.

[0005] DE 10 2017 214 952 B2 describes a display device, a method for manufacturing a display device, an apparatus, a method, and a computer-readable storage medium having instructions for operating the display device.

[0006] Because the content displayed on this screen can be seen through the windshield from outside the vehicle, there is no privacy. This is especially undesirable when displaying private and personalized information. Furthermore, when the screen also projects light forward through the windshield, it can also interfere with other vehicles or pedestrians. Summary of the Invention

[0007] The purpose of this invention is to improve privacy when displaying content in a motor vehicle.

[0008] The proposed objective is achieved by the device according to the invention as described in the parallel claims. Advantageous improvements are given by the dependent claims.

[0009] The present invention is based on the idea of ​​combining a transparent screen element with a polarizing element. Here, a polarizing element is understood as a component or assembly designed to reduce or even block light actively emitted by the screen element. A polarizing element can be, for example, a light-shielding element, i.e., a sheet or film used to block light, such as circularly polarized light or linearly polarized light, preferably circularly polarized light. Therefore, a polarizing element can also be called a screen light-shielding element or a screen light-filtering element.

[0010] In other words, the polarizing element is designed and coordinated with the screen element so that, in a state where the display surface is transparent to ambient light, the polarizing element acts or functions like a polarizer, filtering out light from the screen element. For this purpose, the polarizing element can be designed, for example, as a polarizer and / or have a structure that reduces light chemically. In particular, because the structure and / or properties of the polarizing element are combined with the structure and / or properties of the screen element, the polarizing element can filter out light from the screen element. In other words, the polarizing element is preferably coordinated with the properties of the screen element. Since ambient light still passes at least partially through the combination of the polarizing element and the screen element in this invention, the polarizing element can also be referred to as a partially transparent polarizing element.

[0011] This provides a high degree of privacy for occupants in motor vehicles. Furthermore, the displayed content is less likely to dazzle or even disturb other vehicles and pedestrians.

[0012] Therefore, the display device according to the invention includes a transparent screen element having a front side and a rear side opposite to the front side. The display device is a device, device component, or device assembly, i.e., it is designed to display content, such as a graphical user interface (GUI). The screen element is designed to display the one or more display contents by means of all light-emitting elements, such as organic light-emitting diodes (OLEDs).

[0013] Furthermore, the display device includes a polarizing element arranged planarly on the rear side of a transparent screen element. This polarizing element is designed to weaken, reduce, or even block light actively emitted by at least one light-emitting element of the transparent screen element. Preferably, the light from the light-emitting element can be weakened or blocked by means of a polarization structure of the polarizing element, such as a frictional / roughened structure. In other words, the transparent polarizing element is designed to weaken, reduce, or block the light from the transparent screen element, such as a light-emitting diode, while remaining transparent to ambient light. Thus, the user can see through the display device from either side or from either side of the transparent screen element, but can only see the displayed content when looking forward. This achieves the aforementioned advantages.

[0014] The screen element of the display device can preferably be designed as a so-called TOLED display (transparent organic light-emitting diode display), that is, a screen with transparent organic light-emitting diodes.

[0015] If the polarizing element has a friction structure, the effect is further enhanced. Thus, the effect is significantly enhanced, especially if the display device additionally has a surface-type reflective protection element, i.e., a surface-type component for suppressing the reflection of ambient light from the screen element. The reflective protection element can also be called a reflection suppression element. The reflective protection element may, for example, include a polarizing filter designed to linearly polarize light, wherein the polarizing structure of the polarizing element is oriented towards the friction direction / roughening direction of the friction structure. Preferably, the polarizing structure extends at a predetermined angle to the friction structure, preferably less than 180°, especially perpendicularly or at a right angle. Thus, the friction structure can also be called an antiparallel friction structure.

[0016] Preferably, the optional reflective protection element can be arranged on the front side of the transparent screen element, thereby polarizing the ambient light incident into the transparent screen element. In other words, the polarizing element is not part of the polarizing element. Ideally, the reflective protection element can be arranged on both the front and rear sides of the screen element, i.e., between the screen element and the polarizing element. The effect is particularly good if the corresponding reflective protection element has a polarizing filter element, i.e., a polarizing filter, and a delay element. The delay element is understood as a sheet or film that delays light waves, especially a Lambda / 4 sheet or Lambda / 4 film.

[0017] By combining a polarizing filter and a delay element, ambient light in front of the screen element is polarized and delayed, so that circularly polarized ambient light hits the screen element and (at least a portion of the ambient light) passes through the screen element, where it is "de-circularized" again by a rear-side reflective protection element and hits the polarizing element. Light actively emitted by the screen element, such as from a light-emitting diode, only passes through the reflective protection element. If an exemplary light-emitting diode emits normal unpolarized light, the rear-side reflective protection element converts this unpolarized light into circularly polarized light, which then hits the polarizing element. Here, the ideal polarizing element for blocking light from the light-emitting element (and for transmitting ambient light) is at least one vertically aligned display element and / or at least one twisted nematic display element, preferably one vertically aligned display element or one twisted nematic display element. Thus, optionally, the display element may have, for example, a polarizing filter element, or block light from the light-emitting element by means of a chemical structure and / or a frictional structure.

[0018] If, according to another embodiment of the display device according to the invention, the transparent polarizing element is designed as vertically aligned display elements, such as a vertically aligned screen, or optionally has at least two vertically aligned display elements, then although the display surface still appears transparent, the effect of the displayed content being visible only in one direction is particularly good. Optionally, the vertically aligned display elements can be designed as thin films or sheets. Vertical alignment techniques, such as multi-quadrant vertical alignment (MVA) and patterned vertical alignment (PVA), are specific implementations of liquid crystal displays known to those skilled in the art.

[0019] Excellent results are also achieved in display devices where the transparent polarizing element is designed as a twisted nematic display element, i.e., a liquid crystal display with a nematic rotation unit, or optionally, two or more twisted nematic display elements. For example, there may be one twisted nematic display element. Optionally, the at least one twisted nematic display element may be designed as a thin film or sheet.

[0020] In another embodiment, the transparent polarizing element of the display device may have a twisted nematic display element and a vertically aligned display element. In other words, the transparent polarizing element may be designed as a combination of a twisted nematic display element and a vertically aligned display element.

[0021] According to another embodiment of the display device according to the invention, the screen element is designed to emit only unpolarized light by means of the at least one light-emitting element. In other words, the screen element can be designed to emit only unpolarized light by means of all the light-emitting elements. Preferably, an improved scheme is used in combination with a polarizing element having a friction structure, wherein, preferably, at least one reflection suppression element can be additionally arranged on the screen element. Ideally, the reflection protection element can be arranged on the front side and the rear side of the screen element, respectively, i.e., between the screen element and the polarizing element. The effect is particularly good if the corresponding reflection protection element has a polarizing filter element and a delay element, especially a Lambda / 4 sheet or a Lambda / 4 film. Here, the ideal polarizing element is at least one vertically aligned display element and / or at least one twisted nematic display element, preferably one vertically aligned display element or one twisted nematic display element.

[0022] If the screen element only has a light-emitting element that emits polarized light, the polarizing element can be arranged to block the polarized light of the light-emitting element, such as a light-emitting diode, without blocking ambient light passing through the screen element. In this embodiment, the polarizing element preferably has a polarizing filter element, for example, designed as a polarizing filter. In this embodiment, it is also possible to have no twisted nematic display elements or vertically arranged display elements.

[0023] If the polarizing element is designed to not have a polarizing filter, that is, without a polarizing filter, the display surface of the display device will not be additionally darkened.

[0024] The objectives described above are achieved by a motor vehicle having a display device according to one of the embodiments described above. This provides the advantages described above.

[0025] Preferably, the display device can be designed as a window of the vehicle. The size of the window allows for the display of particularly private information to the user inside the interior space. A disadvantage of using this display device as a windshield design is that windshields are frequently struck by stones and may require replacement. Furthermore, the windshield design is more complex because it is curved and angled. These disadvantages can be avoided if the display device is independently positioned on or within the interior trim of the vehicle, with the front facing the interior space and the rear facing the window, preferably the windshield.

[0026] The present invention also includes improvements to the motor vehicle according to the invention, which have the features already described in conjunction with improvements to the display device according to the invention. For this reason, corresponding improvements to the motor vehicle according to the invention will not be described again here.

[0027] The motor vehicle according to the invention is preferably designed as an automobile, especially a passenger car or a truck, or a bus or a motorcycle.

[0028] The present invention also includes combinations of features of the described embodiments. Attached Figure Description

[0029] The embodiments of the present invention will now be described. Wherein:

[0030] Figure 1 A schematic three-dimensional view of an embodiment of a motor vehicle according to the present invention is shown from an external perspective looking at the display device, the motor vehicle having an embodiment of the display device according to the present invention;

[0031] Figure 2 Another schematic three-dimensional view of an embodiment of a motor vehicle according to the invention is shown from an interior perspective looking toward the display device, the motor vehicle having an embodiment of the display device according to the invention;

[0032] Figure 3 A schematic diagram of another embodiment of the display device according to the present invention is shown in cross-section; and

[0033] Figure 4 A schematic three-dimensional diagram of another embodiment of the display device according to the present invention is shown. Detailed Implementation

[0034] The embodiments described below are preferred embodiments of the present invention. The components of the embodiments described in the embodiments represent individual features of the invention that are considered independent of each other, and these features also independently improve the invention. Therefore, the disclosure should also include combinations of features different from those of the illustrated embodiments. Furthermore, the described embodiments may be supplemented by other features of the invention already described.

[0035] In the figure, the same reference numerals represent elements with the same function.

[0036] Figure 1 The principle of the display device 10 according to the present invention is shown. Figure 1 The display device is illustrated, exemplarily, in a manner arranged within a motor vehicle 12. The motor vehicle 12 may be, for example, a passenger car, and the display device 10 may be designed as a separate screen, which may be arranged on an interior element 14 of the motor vehicle 12, preferably on the dashboard. Figure 1 From a three-dimensional perspective, the rear side of the display device 10 can be seen, which faces the window glass 16 of the motor vehicle 12, preferably the windshield.

[0037] As an alternative to implementing a separate screen in the vehicle 12, the display device 10 may also be designed as a window 16 of the vehicle, such as a windshield or side window.

[0038] Figure 1 A display device 10 is shown, which outputs display content, such as a graphical user interface (GUI). Figure 1 The line of sight from the outside of the vehicle to the vehicle 12 indicates that the displayed content is not visible from the outside.

[0039] Figure 2 The vehicle 12 is shown in three dimensions from a viewpoint within the interior space of the vehicle 12, directed towards the front or inner side of the display device 10. This front or inner side may also be referred to as the "viewing side." From the interior space, multiple displays 18, such as multiple graphical user interfaces, can be seen. Additionally, the current speed ("50 km / h") may be displayed, for example.

[0040] Figure 3 The structure of the display device 10 is shown schematically in cross-section. As a transparent screen element 20, the display device 10 may, for example, include a screen composed of microLEDs. However, common microLED screens are currently only available with a limited display area; therefore, the transparent screen element 20 is preferably designed as a TOLED (Transparent OLED Display).

[0041] exist Figure 3 The cross-section of the display device 10 shows that it is visible on the front side 24 of the transparent screen element 20 in the viewing direction 22 (i.e., if corresponding to, for example, the view in the viewing direction 22). Figure 1 and Figure 2 For example, from the perspective of the occupant, the displayed content 18 is seen. In this example, the front side 24 of the screen element 20 may also correspond to the front side (or the inner side or the visible side) of the display device 10.

[0042] On the rear side of screen element 20, opposite to the front side 24, a polarizing element 26 is arranged in a planar manner, for example, by bonding, laminating, or otherwise fixed. The polarizing element 26 polarizes the light emitted by screen element 20 (actively emitted by a light-emitting element of screen element 20, not shown in the figure), that is, it can have a polarization effect. In other words, the polarizing element 26 itself can polarize the light actively emitted by screen element 20; that is, the polarizing element can optionally be designed as a polarizer; or the polarizing element can otherwise weaken or even completely block the light actively emitted by screen element 20, so that the displayed content 18 is invisible on the rear side of display device 10 and consequently to a person looking at the rear side of display device 10. However, a person behind display device 10 can still view it through screen element 20. Figure 3 For illustration, the blocking direction 28 is shown, which is the direction along which the displayed content 18 is made invisible, that is, the direction along which the light of the screen element 20 is weakened, blocked or filtered out.

[0043] The polarizing element 26 may be, for example, a switchable thin film, which may be designed to function like a polarizer in a transparent state and “filter out” the display content 18. Thus, alternative designs for the polarizing element 26 may include designs that are switchable layers, such as a TSD layer, an SPLC layer (“Smart-Glass”), or a PDLC layer.

[0044] One of the following design options for the polarizing element 26 is preferred. When viewed from both sides of the display device 10 with the transparency remaining constant or nearly constant, the attenuation or even blocking effect of the light emitted by the light-emitting element of the screen element 20 (e.g., LED or OLED, preferably transparent OLED light) is multiplied when using a polarizing element 26 designed as a twisted nematic display element or a vertically aligned element, or when using a polarizing element 26 including such a display element. Ideally, in this embodiment, the transparent screen element 20 can be designed to output only unpolarized light. Here, the polarizing element 26 is preferably designed as a light-shielding element and / or "smart glass".

[0045] Figure 4An example is shown in which the display device 10 may be designed as a screen element 20, such as an OLED screen, preferably a transparent OLED screen. Here, the light-emitting diodes preferably emit unpolarized light. Here, arrow 30 points in the direction of the visible image, i.e., towards the front side 24 of the screen element 20. The transparent screen element 20 may optionally be disposed on its rear side on a carrier glass 32, the carrier glass being, for example, 5 mm thick and made of glass. Reference numeral 34 indicates the portion of the rear side of the transparent screen element 20 disposed on the carrier glass 32; ideally, the rear side of the transparent screen element rests directly on the carrier glass 32, i.e., without a bonding layer.

[0046] The carrier glass 32 can be disposed on the polarizing element 26 via, for example, a 0.2 mm thick connecting layer 36. For anyone skilled in the art, the connecting layer 36 can be a connecting layer known from the prior art, such as an adhesive layer or a laminate. Thus, when the transparent screen element 20 outputs display content, the display content is not visible in the viewing direction 35.

[0047] exist Figure 4 In the example, polarizing element 26 can be ideally designed as a twisted nematic display element, such as a twisted nematic screen, as described above; or as a vertically aligned display element, such as a vertically aligned screen. Such a screen typically has multiple inner layers, which... Figure 4 As indicated in the text. Optionally, the polarization element 26 may have two display elements, such as a twisted nematic screen and a vertically aligned screen. For this variant, Figure 4 Multiple display elements of polarization element 26 are shown.

[0048] The transparent screen element 20 may preferably include a reflective protective element on the front side 24 (in Figure 4 (Not shown separately), the reflective protection element may, for example, comprise a composite film consisting of a linear polarizing film and a Lambda / 4 film to reduce the reflection of ambient light incident on the screen element 20. Ambient light incident from the interior space of the vehicle 12 is delayed in phase, for example, by 45 degrees, by the reflective protection element and is here converted into circularly polarized light with, for example, left-handed polarization, which may extend parallel to and perpendicular to the optical axis. This circularly polarized light can be converted back to right-handed circular polarization and blocked by the front reflective protection element to improve contrast.

[0049] Subsequently, the left-handed circularly polarized ambient light that penetrates the screen element 20 can be "de-circularized" or linearized again at a reflective protective element arranged on the rear side of the screen element 20, which may be, for example, a component of the screen element 20 or the polarization element 26.

[0050] The polarizing elements 26 on the carrier glass 32, such as twisted nematic display elements and / or vertically aligned display elements, may have antiparallel friction structures. These friction structures, for example, at the boundary layer, can linearly polarize the light from the light-emitting element by means of the other reflective protective element. If the linear polarization structure is perpendicular to the friction direction, the image of the light-emitting element is significantly weakened. The brightness can be adjusted according to the angle between the linear polarization direction and the friction direction.

[0051] According to another embodiment, the polarizing element 26 may be designed as a polarizing filter or have a polarizing filter. Thus, the transparent screen element 20 may be designed to emit polarized light by means of its light-emitting element. OLEDs are known in the art to those skilled in the art; to avoid reflective filters such as those found in mobile phones or windows, OLEDs provide polarized light through chemical structures. If the light-emitting element of the screen element 20 (e.g., an LED or organic LED) is designed to emit polarized light, then the polarizing element 26 or a component thereof may be arranged to rotate in a direction corresponding to the polarized light.

[0052] In general, the examples illustrate how the present invention provides a transparent screen element 20, preferably a T-OLED, which is "invisible" from the rear side by means of a polarizing element 26, such as a switchable thin film.

[0053] Polarizing element 26, such as an example switchable thin film or switchable layer, can be oriented, for example, as a polarizer, so that it filters out the light of the example T-OLED in a transparent state.

[0054] Therefore, by targeting the thin film, which is an example of a polarizer, light emitted toward, for example, the front glass can be blocked.

[0055] Therefore, the screen element 20 of the display device 10 emits light only in the direction of the driver, and the content of the display is not visible to the outside.

[0056] This does not incidentally affect the transparency of the display. If the display is switched to "transparent," pedestrians can see the vehicle 12 through the display from the outside, but cannot see the (illuminated) screen content. At the same time, the driver sees the (illuminated) graphics, specifically the GUI (Graphical User Interface), from the same position on the other side.

[0057] However, the content shown is only visible on one side. Although light is blocked or reduced on the other (e.g., the rear) side, the display (i.e., screen element 20, and / or polarizing element 26) remains transparent in both directions.

[0058] This effect can be achieved by a polarizing element 26, such as a second switchable layer (e.g., LCD), following the actual display (O-LED).

[0059] The display device 10 has the desired display light-emitting performance in only one direction. Similarly, the display remains transparent in two directions.

Claims

1. A display device (10), comprising: - A transparent screen element (20), the screen element having a front side (24) and a rear side opposite to the front side (24), - A polarizing element (26) is arranged in a planar manner on the rear side of the transparent screen element (20). This polarizing element is designed to reduce the light actively emitted by at least one light-emitting element of the transparent screen element (20), wherein... The polarization element has an antiparallel friction structure, and, The display device further includes at least one surface-type reflective protection element for reducing ambient light reflection in the screen element (20); the reflective protection element is arranged between the screen element and the polarizing element on the front side and the rear side of the screen element; wherein the reflective protection element has a polarizing filter element designed to polarize light rays, wherein the polarizing structure of the polarizing element (26) is oriented at a predetermined angle to the friction direction of the friction structure, wherein the screen element (20) is designed as a screen with transparent organic light-emitting diodes.

2. The display device (10) according to claim 1, wherein, The transparent polarizing element (26) is designed to be vertically aligned as display elements.

3. The display device (10) according to claim 1, wherein, The transparent polarizing element (26) is designed as a twisted nematic display element.

4. The display device (10) according to claim 1, wherein, The transparent polarizing element (26) is designed as a combination of a twisted nematic display element and a vertically aligned display element.

5. The display device (10) according to any one of claims 1 to 4, wherein, The polarization element (26) is designed to be without a polarization filter.

6. The display device (10) according to any one of claims 1 to 4, wherein, The polarization element (26) includes a polarization filter.

7. The display device (10) according to any one of claims 1 to 4, wherein, The screen element (20) is designed to emit only unpolarized light by means of the at least one light-emitting element.

8. The display device (10) according to any one of claims 1 to 4, wherein, At least one light-emitting element of the transparent screen element (20) is designed to emit polarized light.

9. A motor vehicle (12) having a display device (10) according to any one of the preceding claims.

10. The motor vehicle (12) according to claim 9, wherein, The display device (10) is designed as the window glass (16) of a motor vehicle (12).

11. The motor vehicle (12) according to claim 10, wherein, The display device (10) is independently arranged on or on the interior element (14) of the motor vehicle (12), wherein the front side (24) of the screen element (20) faces the interior space of the motor vehicle (12), and wherein the rear side faces the window glass (16) of the motor vehicle (12).

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