DE102021111333A1 - Display device for generating a light image in a vehicle and method for generating a color-true and homogeneous light image formed from pixels - Google Patents

Abstract

The invention relates to a display device (12) for generating a light image in a vehicle (10), having at least one transparent protective layer (14), at least one translucent decorative layer (16) made of wood and/or cellulose and at least one display device (18), wherein the decorative layer (16) is arranged between the protective layer (14) and the display device (18). The invention also relates to a vehicle, a method for generating a color-true and homogeneous light image formed from pixels in such a display device (12) and a computer program product.

Description

The present invention relates to a display device for generating a light image in a vehicle. Furthermore, the invention relates to a method for generating a color-true and homogeneous light image formed from pixels, a computer program product and a vehicle.

In vehicle construction, displays are integrated into the interior to show information such as driving speed or the inside and outside temperature. Conventional displays have a black display area, especially when switched off, which vehicle occupants find annoying or antiquated. To circumvent these disadvantages, transparent displays or unexpected display surfaces are increasingly being used.

Out of CN 209087288 U The result is a control panel with a permeable and touch-sensitive surface that features a wood product panel, an electronic display and touch buttons. The wooden product board is provided with through-holes in which the display and touch buttons are inserted. A wood-based material layer is also arranged on the visible side of the wood product board.

Furthermore goes out WO2019/155159 A1 discloses a touch-sensing device having a touch interface made of a composite material, the composite material comprising a lignocellulosic material impregnated with a resin. The material impregnated with resin allows to make the touch surface stable, whatever the temperature and humidity conditions, to be able to use it both outside and inside.

The display devices known from the prior art have the disadvantage that the surface of the known materials does not achieve sufficient transmission or the appearance of the material is not authentic. In addition, the manufacturing processes are complex and therefore expensive.

The present invention is based on the object of creating a display device, a method for generating a color-true and homogeneous light image formed from pixels, a computer program product and a vehicle that have a high-quality and authentic appearance and at the same time are color-stable, scratch-resistant and inexpensive.

To achieve the object, a display device having the features of claim 1, a method having the features of claim 9, a computer program product having the features of claim 10 and a vehicle having the features of claim 11 are proposed.

Advantageous configurations of the display device are the subject matter of the dependent claims.

A display device for generating a light image in a vehicle has at least one translucent protective layer, at least one translucent decorative layer made of wood and/or cellulose and at least one display device, with the decorative layer being arranged between the protective layer and the display device.

The decorative layer formed from wood and/or cellulose gives the display device a high-quality and authentic appearance. In particular when the display device is switched off, the decorative layer creates a seamless real wood and/or real cellulose look. The protective layer prevents abrasion of the decorative layer and the resulting defects. Furthermore, the protective layer prevents the decorative layer from fading, for example due to solar radiation. A display device is thus created which is scratch-resistant and color-stable. In addition, the display device is inexpensive to manufacture due to its layer structure.

The display device is advantageously used in an interior of a vehicle. For example, the display device can be integrated in a center console of a vehicle.

Due to the layer structure, the display device has a sandwich structure. The layers can be connected to one another in a positive, non-positive and/or material manner. Furthermore, the decorative layer can be connected to the display device in a positive, non-positive and/or material connection.

The protective layer advantageously protects the decorative layer from fading, so that the display device has high color stability. The protective layer can be a thin coating or a glass or plastic sheet.

The decorative layer is advantageously made so thin that the light image displayed on the display device shines through the decorative layer.

The light image can have a large number of image points, which are also referred to as pixels.

In an advantageous embodiment, the display device can be operated by touch. For this purpose, the display device can be a touch display. In this case, both the protective layer and the decorative layer are touch-sensitive, so that when the surface of the protective layer is touched, the pressure is transmitted to the display device. To implement a touch system, a display device can be combined with an indium tin oxide layer (ITO layer) arranged between the decorative layer and the protective layer. In this case, the display device is designed to display light images.

The display device can be a color display. The display device can be flat or planar. Furthermore, the display device can be convex or concave. Furthermore, the display device can be designed as a free-form surface. The display device can thus have a spherical curvature.

In an advantageous embodiment, the display device can be provided with a covering, for example in the form of a textile.

In an advantageous embodiment, the decorative layer is a wood veneer. The wood veneer gives the display device a high-quality and authentic look. In an advantageous embodiment, the wood veneer is a homogeneous and true-color, translucent wood layer. The wood veneer is advantageously thin-walled. The wood veneer is advantageously bleached and/or dark egg-colored on one visible side. This ensures that the wood veneer is UV-resistant to intense light sources. The thin-walled wood veneer can advantageously be produced in a process-stable manner.

In an advantageous embodiment, the wood veneer is made of birch or maple. Both a birch wood veneer and a maple wood veneer can be bleached and/or darkened on the visible side in order to provide UV resistance to intense light sources.

In an advantageous embodiment, the decorative layer has a thickness of between 0.1 mm and 0.25 mm, in particular between 0.15 mm and 0.21 mm. As a result, the wood veneer is sufficiently thin-walled so that the light image displayed on the display device can illuminate or shine through. If the wood veneer is made of maple, then the decorative layer advantageously has a thickness of 0.15 mm. If the wood veneer is birch, then the decorative layer advantageously has a thickness of 0.21 mm. Both the birch wood veneer and the maple wood veneer are advantageously bleached and/or darkened.

In an advantageous embodiment, the protective layer is a cover glass and/or a coating that filters UV light. The cover glass and the coating prevent abrasion on the wood and the resulting defects. Thus, the cover glass or coating provides the scratch resistance of the display device. The UV light filtering coating can also prevent the decorative layer made of wood and/or cellulose from fading due to UV radiation. The UV light filtering coating prevents accelerated aging of the decorative layer. In addition, a UV-light-filtering coating can protect the underlying adhesive bond of the sandwich.

In an advantageous embodiment, the cover glass is etched and/or provided with an anti-reflection coating. The surface, which is matted by etching, and the anti-reflective coating reduce annoying reflections on the cover glass and also make it easier to clean the cover glass. The anti-reflection coating can be, for example, a metallic coating or a coating made of plastic, which is applied by means of physical vapor deposition (PVD). Furthermore, the anti-reflective coating can be a nanostructured surface, which can be formed as a moth's eye surface.

In an advantageous embodiment, at least one bonding layer is provided, which connects the cover layer and the decorative layer to one another. This creates a stable connection between the protective layer and the decorative layer. The bonding layer can also be referred to as an adhesive layer. The bonding layer can have UV-resistant properties. As a result, the bonding layer assumes UV resistance and resistance to intense light sources and prevents the decorative layer from fading.

In an advantageous embodiment, an air layer or a bonding layer is provided between the decorative layer and the display device. The bonding layer connects the decorative layer to the display device. The bonding layer can have UV-resistant properties.

In an advantageous embodiment, the display device is an LCD display, an OLED display, a mini or micro LED display. As a result, a bright display is made available, which enables the decorative layer to be transilluminated. All displays can be designed as touch displays.

According to a further aspect, a vehicle with a display device is proposed.

According to a further aspect, a method for generating a color-true and homogeneous light image formed from pixels in a display device is proposed. In the method, at least one test image formed from pixels is first output on the display device and a luminance for each color channel of each pixel is measured. Thereafter, the measured luminance for each color channel of each pixel output by the display device is compared with a luminance for each color channel of each pixel output by the display device of the test image, and a light transmittance is determined for each color channel of each pixel output by the display device. A luminance correction value is then determined for each color channel of each pixel by inverting the determined light transmittance. Finally, the determined luminance correction values are applied to an image input signal fed into the display device.

Despite the acceptable transmission of the decorative layer, there is a luminance inhomogeneity corresponding to the wood or cellulose texture in the perceptible light image and a color shift. The reason for this are local changes in light transmission in the wood or cellulose decor and pigments that act as color filters. Despite the real wood or real cellulose layer, the process produces a colour-true and homogeneous video image. The process enables a homogeneous luminance across the entire pattern from the perspective of the occupants. The method also corrects for color shift by multiplying the color values in the output of the source per pixel. The method can also be automated in the finished vehicle in the factory. For this purpose, the interior cameras installed in the vehicle can be used for measuring and comparison. The luminance of each pixel output by the display device is thus advantageously compared with a luminance of each pixel output by the display device, ie without a protective layer, decorative layer and bonding layer. The test image can also be referred to as a reference image. The input image signal generates an input image composed of pixels on the display device. By applying the ascertained luminance correction values to the image signal, a color-corrected, homogenized output image is created on the display device. For example, the image input signal can be a logo.

A color channel is a primary color of a color space used to store a color digital image. The color channel thus provides information about the color components contained in the light image. So-called RGB color images advantageously have three color channels, namely green, red and blue. Colored light images are thus generated by additively superimposing green, red and blue pixels.

According to a further aspect, a computer program product is proposed, comprising instructions which, when the program is executed by an evaluation device, cause the latter to carry out the method according to claim 10.

The evaluation device can be a data processing device, such as a computer or a control unit. In the case of a control unit, it can be the control unit integrated in the display device or the central control unit of the vehicle.

• 1 ein Fahrzeug mit einer Anzeigevorrichtung;
• 2 einen vergrößerten Ausschnitt eines Querschnitts durch die Anzeigevorrichtung;
• 3 ein Blockdiagramm zur Illustration eines ersten Schritts eines Verfahrens zur Erzeugung eines farbtreuen und homogenen, aus Bildpunkten gebildeten Lichtbildes bei der Anzeigevorrichtung;
• 4 ein Blockdiagramm zur Illustration eines zweiten Schritts des Verfahrens;
• 5 ein Blockdiagramm zur Illustration eines dritten Schritts des Verfahrens; und
• 6 ein Blockdiagramm zur Illustration eines vierten Schritts des Verfahrens.

A vehicle, a display device, a method for generating a color-true and homogeneous light image formed from pixels in the display device and other features and advantages are explained in more detail below using an exemplary embodiment that is shown schematically in the figures. Here show:

• 1 a vehicle having a display device;
• 2 an enlarged detail of a cross section through the display device;
• 3 a block diagram to illustrate a first step of a method for generating a color-true and homogeneous light image formed from pixels in the display device;
• 4 a block diagram to illustrate a second step of the method;
• 5 a block diagram to illustrate a third step of the method; and
• 6 a block diagram to illustrate a fourth step of the method.

In 1 A vehicle 10 with a display device 12 is shown. The vehicle 10 can be a motor vehicle with an internal combustion engine or a drive machine designed as an electric motor.

The display device 12 is used to generate a light image in the vehicle 10, by means of which information such as the inside and outside temperature or the speed can be displayed.

As in 2 As can be seen, the display device 12 has a light-transmissive protective layer 14, a bonding layer 15, a through lightable decorative layer 16 and a display device 18 on.

The protective layer 14 is a cover glass 20, which prevents abrasion of the decorative layer 16 and the resulting defects. The cover glass 20 is etched and/or provided with an anti-reflection coating, not shown. The surface, which has been frosted by etching, and the anti-reflective coating reduce reflections on the cover glass and also make it easier to clean the cover glass. The anti-reflection coating can be, for example, a metallic coating or a coating made of plastic, which is applied by means of physical vapor deposition (PVD). Furthermore, the anti-reflective coating can be a nanostructured surface, which can be formed as a moth's eye surface.

The cover glass 20 can be provided with a UV-resistant coating, not shown, which protects the wooden decorative layer from excessive solar radiation or intense light sources and thus prevents the color of the decorative layer 16 from fading. In addition, the UV-resistant coating reduces aging effects of the bonding layer 15.

The bonding layer 15 connects the protective layer 14 and the decorative layer 16 to one another in a cohesive manner. The bonding layer 15 also has UV-resistant properties in order to protect the decorative layer 16 from excessive solar radiation and thus from fading.

The decorative layer 16 is a thin layer of wood that is designed as a wood veneer 22 . The wood veneer 22 can be birch or maple. On the side facing the vehicle occupants, the wood veneer 22 is bleached and/or dyed dark in order to provide a certain UV resistance.

If the wood veneer 22 is made of birch, then the thickness of the decorative layer 16 or wood veneer 22 is 0.21 mm. If the wood veneer 22 is maple, then the thickness of the decorative layer 16 or wood veneer 22 is 0.15 mm.

The display device 18 is an OLED display, an LCD display, a mini or micro LED display, with an air gap 24 being provided between the decorative layer 16 and the display device 18 . A bonding layer 15 can be provided instead of the air gap 24 .

Despite the acceptable transmission of the thin decorative layer 16 or the wood veneer 22, there is a luminance inhomogeneity corresponding to the wood texture in the perceptible light image and a color shift. The reason for this are local changes in the light transmission in the wood veneer 22 and pigments that act as color filters.

To generate a true-color and homogeneous light image, a method for generating a true-color and homogeneous light image formed from pixels in the display device 12 is described below using the 3 until 6 explained.

in a 3 In the first step shown, an input image or reference image is generated in the display device 18, which consists of a large number of picture elements or pixels. Each pixel has three color channels, namely red R, green G and blue B, which add up to white W.

The resulting perceptual image in display device 12 is represented as perceptual red R', perceptual green G', perceptual blue B', and perceptual white W' for each color channel of each pixel. The resulting, perceptible image can be measured using cameras installed in the vehicle 10, which are not shown here.

in a 4 In the second step shown, the luminance for each color channel R, G, B of each pixel output by the display device 12 is compared with a luminance for each color channel R', G', B' of each pixel of the unmodified test image and light transmittances for each Color channel R', G', B' of each pixel output by the display device 12 is determined.

in a 5 In the third step shown, a luminance correction value is determined for each color channel R', G', B' of each pixel by inverting the light transmittance determined for each color channel R", G", B".

in a 6 In the fourth step illustrated, the determined luminance correction values are applied to an image input signal fed into the display device 18 . In the present case, the luminance correction values are applied to a white image, resulting in an inverted white W", which is then output as a true-color and homogeneous white W.

The decorative layer 16 made of wood gives the display device 12 a high-quality and authentic appearance. In particular when the display device 12 is switched off, the decorative layer 16 produces a seamless real wood and/or real cellulose look. The protective layer 14 prevents abrasion of the decorative layer 16 and the resulting defects. Furthermore, the protective layer 14 prevents the decorative layer 16 from fading, for example as a result of solar radiation. A display device 12 is thus created which is scratch-resistant and color-stable. In addition, the display device 12 is inexpensive to manufacture due to its layer structure.

reference list

10

vehicle

12

display device

14

protective layer

15

bonding layer

16

decorative layer

18

display device

20

coverslip

22

wood veneer

24

air gap

R

Red

G

Green

B

Blue

W

White

R'

noticeable red

G'

noticeable green

B'

noticeable blue

W'

noticeable white

R"

inverted red

G"

inverted green

B"

inverted blue

W"

inverted white

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• CN 209087288 U [0003]
• WO 2019/155159 A1 [0004]

Claims (11)

Display device (12) for generating a light image in a vehicle (10), having at least one transparent protective layer (14), at least one translucent decorative layer (16) made of wood and/or cellulose and at least one display device (18), the decorative layer (16 ) is arranged between the protective layer (14) and the display device (18). Display device (12) after claim 1 , characterized in that the decorative layer (16) is a wood veneer (22). Display device (12) after claim 2 , characterized in that the wood veneer (22) is made of birch or maple. Display device (12) according to one of the preceding claims, characterized in that the decorative layer (16) has a thickness of between 0.10 mm and 0.25 mm. Display device (12) according to one of the preceding claims, characterized in that the protective layer (14) is a cover glass (20) and/or a UV light filtering coating. Display device (12) after claim 5 , characterized in that the cover glass (20) is etched and / or that the cover glass (20) is provided with an anti-reflective coating. Display device (12) according to one of the preceding claims, characterized in that at least one bonding layer (15) is provided, which connects the protective layer (14) and the decorative layer (16) to one another. Display device (12) according to one of the preceding claims, characterized in that the display device (18) is an LCD display, an OLED display or a mini or micro LED display. Vehicle (10) with a display device (12) according to one of Claims 1 until 8th . Method for generating a color-true and homogeneous light image formed from pixels in a display device (12) according to one of Claims 1 until 8th , which comprises the following steps: a. Outputting at least one test image formed from pixels on the display device (12) and measuring a luminance for each color channel (R', G', B', W') of each pixel; b. Comparison of the measured luminance for each color channel (R', G', B') of each pixel output by the display device (12) with a luminance for each color channel (R, G, B) of each pixel output by the display device (18). of the test image and determination of a degree of light transmission for each color channel (R', G', B') of each pixel output by the display device (12); c. determining a luminance correction value for each color channel (R", G", B", W") of each pixel by inverting the determined light transmittance; and d. Applying the determined luminance correction values to an image input signal fed into the display device (18). Computer program product comprising instructions which, when the program is executed by an evaluation device, cause the latter to carry out the method claim 10 to execute.

Images