DE102023135059A1 - Display device - Google Patents

Abstract

A display device with a first e-paper element (2) comprising at least two types of color pigments, which is provided with a TFT active matrix (5) and is designed as a high-resolution bistable matrix display and forms a display element (6), is characterized in that on the front side (20) of the first e-paper element (2), which forms a viewing side, a second e-paper element (4; 4') comprising at least one type of color pigment is provided, which is provided with transparent electrodes and forms a low-resolution masking display (7).

Description

TECHNICAL FIELD

The invention relates to a display device with a first e-paper element having at least one color pigment according to the preamble of patent claim 1. It further relates to a vehicle, in particular a motor vehicle, which is provided at least in regions on an inner and/or outer surface with a display device according to one of the preceding claims.

BACKGROUND OF THE INVENTION

When designing vehicles, it is sometimes desirable to integrate display devices capable of displaying graphics or text for road users or passengers into the vehicle body or other vehicle components. E-paper display elements are particularly suitable for this purpose, as they enable a bistable display and therefore only require electrical power when the display changes.

An e-paper display element contains a display layer arranged between two electrode layers with microcapsules containing, for example, positively charged white pigment particles and negatively charged black pigment particles in a transparent, viscous medium. Briefly applying an electrical voltage to the two electrode layers in the area of a microcapsule causes either the white pigments or the black pigments of this microcapsule to move upwards toward the viewing side. Instead of the white and black pigments, colored pigments can also be used. The display is maintained even after the electrical voltage is switched off and is therefore bistable.

High-resolution e-paper display elements are usually equipped with a TFT matrix on their reverse side, allowing very small areas of the display layer to be addressed, enabling text and detailed graphics to be displayed. These high-resolution e-paper display elements are limited in terms of their design. These high-resolution e-paper display elements are usually rectangular and can be trimmed at a maximum of two edges. Therefore, the visually appealing integration of such high-resolution e-paper display elements into body surfaces or other free-form surfaces of a vehicle is only possible to a limited extent. At the very least, such integration is difficult, as demarcated rectangular surfaces are rarely available on a vehicle. The aesthetically pleasing integration of display devices into a vehicle body or other vehicle component, for example, in the vehicle interior, therefore requires the contour of the display device to be adapted to almost any contoured surface.

Low-resolution e-paper display elements, which consist of relatively few individually contacted segments, are flexible in their design, but they cannot display detailed information.

STATE OF THE ART

From the US 2019/0283686 A1 A flexible display device for a motor vehicle is known, which has a receiving device provided on the motor vehicle, to or in which a flexible display can be detachably attached. Flexible glass and/or a material comprising graphene and/or flexible electronic paper and/or organic thin-film transistor (OTFT) material and/or MEMS surfaces can be used as the deformable material, for example, or OLED technologies can be used.

From the US 2020/0258478 A1 A vehicle is known which is provided with a multi-layered display device visible from the inside and outside, with a blocking intermediate layer provided between an inner display layer and an outer display layer.

The WO 2021/154418 A1 discloses an electronic advertising board which can be mounted on the outside of a motor vehicle and which has a display device which can be mounted, for example, on a vehicle door and a camera for recording viewers of the display device.

All of these display devices have the disadvantage that they appear as foreign bodies in or on the vehicle and are not integrated into the vehicle design.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide an energy-saving display device with a high-resolution display element for attachment to a vehicle, which can be adapted, in particular in the shape of its outer contour, to the shape of the vehicle or to surface areas of the vehicle and can thus be integrated into the surface design.

This problem is solved with the features of patent claim 1.

A display device equipped with a first e-paper element comprising at least two types of color pigments, which is provided with a TFT active matrix and is configured as a high-resolution bistable matrix display and forms a display element, is characterized in that a second e-paper element comprising at least one type of color pigment is provided on the front side of the first e-paper element, which forms a viewing side. This second e-paper element is provided with transparent electrodes and forms a low-resolution masking display. For example, the transparent electrodes are configured as passive electrodes.

ADVANTAGES

This inventive arrangement of a first e-paper element provided with a TFT active matrix, which forms a high-resolution bistable matrix display for displaying text and/or images, and a low-resolution masking display arranged above it makes it possible to conceal the angular, in particular rectangular, display contour predetermined by the TFT matrix by means of the essentially arbitrarily selectable flat shape of the masking display and to adapt it to the associated surface area of the vehicle on or at which the display element is to be attached. The first e-paper element can thus be attached almost inconspicuously inside the vehicle, for example on the dashboard, or outside on the vehicle body. Equipping the first e-paper element with two types of color pigments, for example a white and a black type of color pigment, enables, for example, the high-contrast representation of characters, in particular with the aid of the TFT matrix. More than two types of color pigments can also be provided in the first e-paper element, for example to enable colored representations. The coloring of the low-resolution second e-paper element and the high-resolution first e-paper element can be coordinated with one another.

Because the associated electrodes do not require a strict matrix structure, the masking display can be designed essentially as desired with regard to its outer peripheral contour, allowing it to be optimally adapted to a vehicle surface in the interior or on the exterior of the body. For example, a complexly shaped vehicle door or vehicle side panel equipped with a display device according to the invention can be extensively covered with the second e-paper element configured as a low-resolution masking display, which then assumes the outer contour of the vehicle side panel or vehicle door. This masking display can then be provided with an inner contour that can also be designed essentially as desired, surrounding a see-through area that provides a view of the first e-paper element located underneath, i.e., the high-resolution matrix display.

The display device according to the invention thus comprises two essential components: a first e-paper element configured as a display screen with controllable electrodes arranged in the form of a TFT active matrix, and a second e-paper element arranged above the first e-paper element on the viewing side, the electrodes of which cover essentially freely definable surface areas. These two e-paper elements are each preferably designed as films. To form the display device, they are preferably bonded to one another, for example, by adhesive bonding, using the principle of "optical bonding."

Further preferred and advantageous design features of the display device according to the invention are the subject of subclaims 2 to 10.

The second e-paper element preferably has only one type of color pigment. This makes it possible to make the second e-paper element either transparent in some areas or opaque using the color pigments. This second e-paper element, facing the viewer, can, in its at least partially transparent state, allow a view of the underlying first e-paper element with the display it forms, or—in its opaque state—prevent a view of it. This second e-paper element can extend over the entire surface of the first e-paper element, since it can be made transparent, thus allowing a view of the first e-paper element. A display device constructed in this way can, for example, be applied to a surface of a vehicle with almost any contour or shape and, using the second e-paper element, can impart a color or color pattern to this surface. If this second e-paper element is made transparent in some areas, the display of the underlying first e-paper element becomes visible. Such a transparent area can have almost any contour, since the second e-paper element does not have to have a matrix structure, but its electrodes can be of any shape.

If, however, the second e-paper element is provided with two or more types of color pigments, it can only provide a view of the first e-paper element underneath where it is physically is perforated, i.e., cut out. This cut-out area can also have almost any contour, since the second e-paper element does not have to have a matrix structure; its electrodes can be of any shape.

In both variants, the first e-paper element and the second e-paper element are preferably designed as flexible display foils. This design allows the display device to be optimally adapted to the spatial shape of the vehicle surface on which the display device is to be mounted.

In a preferred embodiment of the display device, which can be combined with other embodiments, a transparent protective layer, preferably of flexible design, is provided on the front side of the second e-paper element, which forms the viewing side. Such a transparent protective layer on the top side of the display device protects the surface of the e-paper display elements located underneath.

Preferably, the TFT active matrix is provided on the back of the first e-paper element facing away from the viewing side, so that the layer with the TFT matrix does not impair the viewer's view of the first e-paper element.

In one embodiment of the invention, a first adhesive layer is preferably provided between the first e-paper element and the second e-paper element, which adhesive layer bonds both e-paper elements together at least in regions.

It is advantageous if the second e-paper element essentially covers the entire surface of the first e-paper element and if both e-paper elements are essentially glued to one another over their entire surface by means of the first adhesive layer.

In an alternative embodiment of the invention, a second adhesive layer is provided between the second e-paper element and the protective layer, which adhesively bonds the protective layer to the second e-paper element essentially over the entire surface.

It is particularly advantageous if the second e-paper element only partially covers the first e-paper element and if both e-paper elements are glued to one another by means of the first adhesive layer in the overlapping area.

Preferably, a second adhesive layer is provided between the second e-paper element and the protective layer, which adhesively bonds the protective layer to the second e-paper element. A potting compound layer is provided between the areas of the first e-paper element not covered by the second e-paper element, which adhesively bonds the protective layer to the first e-paper element. This potting compound layer fills the cavity formed by the cut-out area of the second e-paper element.

The invention is further directed to a vehicle, in particular to a motor vehicle, which is provided at least in regions on an inner and/or outer surface with one of the display devices according to the invention.

Preferred embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1A eine schematische Draufsicht auf eine erste Variante einer erfindungsgemäßen Anzeigeeinrichtung,
• 1B eine schematische Schnittansicht der ersten Variante entlang der Linie I-I in 1A,
• 2A eine schematische Draufsicht auf eine zweite Variante einer erfindungsgemäßen Anzeigeeinrichtung,
• 2B eine schematische Schnittansicht der zweiten Variante entlang der Linie II-II in 2A und
• 3 eine schematische Darstellung einer Steuerungseinrichtung zur Ansteuerung der E-Paper-Elemente in einer erfindungsgemäßen Anzeigeeinrichtung.

It shows:

• 1A a schematic plan view of a first variant of a display device according to the invention,
• 1B a schematic sectional view of the first variant along the line II in 1A ,
• 2A a schematic plan view of a second variant of a display device according to the invention,
• 2B a schematic sectional view of the second variant along the line II-II in 2A and
• 3 a schematic representation of a control device for controlling the e-paper elements in a display device according to the invention.

PRESENTATION OF PREFERRED EMBODIMENTS

Currently available e-paper displays, i.e. display elements that operate on the principle of electronic paper or electronic ink, consist of millions of tiny microcapsules approximately 40 µm in size that contain one or more types of color pigments. E-paper displays with only one type of color pigment are capable of creating a transparent area, meaning that when a charge is applied to a black color pigment particle, for example, it moves sideways and allows light to pass through. They can therefore be switched between transparent and non-transparent.

In e-paper displays with two types of color pigments, the color pigment particles are dissolved in a clear liquid. When a positive or negative electric field is applied, the corresponding color pigment particles migrate to the corresponding electrically charged side. For example, in a black/white e-paper display, the black color pigment particles migrate to the top of the microcapsule, where they become visible to viewer B, and the white color pigment particles migrate to the bottom of the microcapsule and are invisible to viewer B. When the electrical polarity is reversed, this changes, and the white color pigment particles become visible.

E-paper displays with multiple types of color pigments function similarly to the two-color pigment system, where a charge is applied to the color pigments and to the top and bottom surfaces of the electrode to facilitate movement. In this respect, this technology enables the display of a color gamut that could encompass all eight primary colors while maintaining the low power consumption of an e-paper display.

Finally, e-paper displays can be manufactured with or without a TFT active matrix on their back. An e-paper display with a TFT active matrix is capable of producing an image with a high pixel density, such as a high-resolution graphic. Without a TFT active matrix, the e-paper display can only switch between the colors it contains.

1A shows a schematic plan view of a first variant of a display device 1 according to the invention and 1B shows a sectional view of this first variant. The display device 1 has a first, lower e-paper element 2 and a second, upper e-paper element 4, which is provided on the front side 20 of the first e-paper element 2, forming a viewing side. The eye A of a viewer B symbolizes the standard viewing direction V directed at the display device 1.

The first, lower e-paper element 2 is provided on its rear side 22 facing away from the front side 20 with a TFT active matrix 5 which can be electrically controlled by a display control device 3, whereby the first, lower e-paper element 2 is designed as a high-resolution bistable matrix display and forms a graphic display element 6 which is rectangular in its basic shape, as the dashed outline in 1 On this display element 6, characters and graphic representations in black/white or in color can be displayed on a display surface 60 of this display element 6 at a resolution corresponding to the structure of the TFT active matrix 5. For this purpose, the first, lower e-paper element 2 has at least two types of color pigments, for example, black and white color pigments or, for colored graphic representations, color pigments in several different colors.

Such display elements 6, also known as high-resolution e-paper displays, on which text and detailed graphics can be displayed, are limited in terms of their shape. These e-paper displays are usually rectangular or can be trimmed at a maximum of two edges, so their display area 60 is also subject to these geometric restrictions.

For the use of such display elements 6 on the outer skin of a vehicle or on a vehicle interior surface, it may be necessary or desirable for technical or design reasons to provide only a portion 61 of the display surface 60 with a freely selectable outer peripheral contour 62. To enable this despite the geometric restrictions of the high-resolution e-paper element 2 provided with the controllable TFT active matrix 5, the second e-paper element 4 is provided on the front side 20 of the first e-paper element 2 facing the viewer B. This second e-paper element 4 is designed as a low-resolution e-paper display (without a TFT active matrix), i.e. as an e-paper display that consists of a few individually contacted segments and is therefore flexible in its design. This second, upper e-paper element 4 is therefore provided with transparent electrodes (not shown) and forms a low-resolution masking display 7, which, although not capable of displaying detailed information, can be configured with segments of virtually any contour. The transparent, e.g., passive, electrodes assigned to these segments are also electrically connected to the display control unit 3 and controlled by it.

In the 1A and 1B In the variant shown, the upper e-paper element 4 is cut out on the inside along an inner contour line 40 and thus forms a frame 42 which partially covers the underlying high-resolution e-paper element 2 on the outside and leaves it free within the frame 42, thus masking it.

The sectional view of the 1B shows the structure of the display element 1 as a sandwich 8, which is made up of several layers glued together according to the principle of “optical bonding”. is set. The upper e-paper element 4 forming the frame 42 is glued flat to edge regions of the lower e-paper element 2 by means of a first adhesive layer 81. A second adhesive layer 82 is applied to the upper surface of the frame 42, i.e. to the front side 44 of the upper e-paper element 4 facing the viewer B, and glues the frame 42 to a transparent cover layer 9, which consists, for example, of glass or a transparent plastic such as polymethyl methacrylate (PMMA) and mechanically protects the underlying layers as a protective layer. This transparent cover layer forms a carrier material for the e-paper elements 2 and 4. In the cavity 84 surrounded by the lower e-paper element 2, the frame 42 and the transparent cover layer 9, a transparent filler material 86 in the form of a filler layer or potting compound layer is provided, for example an adhesive resin, which is injected into the cavity 84. Two different types of bonding are used, namely a dry bonding (“OCA” - Optically Clear Adhesive) with the adhesive layers 81 and 82 and a wet bonding (“OCR” - Optically Clear Resin) with the filler material 86.

The carrier material, i.e., the transparent cover layer 9, is designed so that the visible surface lies approximately on the same viewing plane as the upper e-paper element 4. To this end, the cover layer 9 is painted black on its rear side 90 facing away from the viewer B in the areas outside the upper e-paper element 4. This results in a continuous surface consisting of the coating and the e-paper element.

In the variant according to the 1A and 1B The lower e-paper element 2 is capable of displaying high-resolution graphics in color or black and white. The upper e-paper element 4 has two or more types of color pigments and can therefore change its color to other predefined colors, but cannot display high-resolution graphics. This upper e-paper element 4 can be cut into any shape and adapt seamlessly to the geometric design specifications of a vehicle. In contrast to a bezel, which is often used as a frame for displays, the upper e-paper element 4 can be animated to a certain extent, even with coordinated colors. The colors of the low- and high-resolution e-paper elements can thus be coordinated with one another, and with the described structure, there is hardly any perceptible depth offset, so that the entire sandwich structure appears to be made from a single piece.

The 2A and 2B The second variant of the display element 1' shown corresponds fundamentally to the first variant of the display element 1 in its structure, so that only the differences will be described below. Otherwise, the explanations for the description of the first variant apply to the second variant. Therefore, the same reference numerals designate the same elements, and the elements that differ from the first variant are provided with different reference numerals.

The one in the 2A and 2B The structure of the display element 1' as a sandwich 8' shown differs from the first display element 1 only in the design of the upper e-paper element 4' in the manner described below. The upper e-paper element 4' is not cut out, but is bonded over its entire surface to the lower e-paper element 2 by means of the first adhesive layer 81' and over its entire surface to the transparent cover layer 9 by means of the second adhesive layer 82', as shown in 2B can be seen.

The upper e-paper element 4' has only one type of color pigment and can therefore be switched between a single color, i.e., non-transparency, and transparency in its regions determined by the respectively assigned electrodes, i.e., the individual segments, by means of the control device 3. The dotted line in Fig. 2A denotes an outline 46 of such an inner region 48 of the upper e-paper element 4', which can be switched between transparency and non-transparency. The frame 42' is formed here by a first segment of the second e-paper element 4', and the inner region 48 surrounded by the frame 42' is formed by a second segment of the second e-paper element 4'. If this inner region 48 is switched to transparent, the viewer B can see the visible part 61 of the display surface 60 of the display element 6 formed by the high-resolution lower e-paper element 2. If the switchable area 48 is non-transparent, the lower e-paper element 2 remains hidden from the view of the viewer B.

The display devices 1, 1' according to the invention, consisting of a sandwich 8 of a high-resolution e-paper element 2 with the TFT active matrix 5 as a graphic display and the low-resolution e-paper element 4 or 4' arranged above it as a masking display 7, also have the classic advantages that result from the use of e-paper displays, such as their preferred design in the form of flexible display foils and thus their bendability and bistability. The display devices 1, 1' can thus be freely designed according to the designer's discretion and are nevertheless capable of displaying text and graphics in high resolution with almost unlimited outline design. The resulting free form of the high-resolution e- Paper Elements 2 can conceal transitions between the two e-paper elements 2 and 4 or 4' even better.

Finally, to create the impression of a monolithic display, the control of the two e-paper elements 2 and 4 or 4' must also be synchronized. This is done via image synchronization performed by the display device 3, as described in 3 is shown schematically. A target image that changes during runtime and is to be displayed on the display device 1, 1' is specified in a first step a). In a synchronizer 30, this target image is transformed in a second step b) into control signals for the TFT active matrix 5 of the first, high-resolution e-paper element 2 and into control signals for the individual areas (segments n, n+1, n+2, ...) of the second, low-resolution e-paper element 4, 4', and the corresponding electrical signals are transmitted in a third step c) from the control device 3 to the e-paper elements 2, 4, 4'. The synchronization is designed such that each individual color pigment is controlled correctly and that the control for the high-resolution e-paper element 2 and the control of all segments of the low-resolution e-paper element 4 or 4' are carried out synchronously.

The invention is not limited to the above embodiment, which merely serves to generally explain the core concept of the invention. Within the scope of protection, the device according to the invention may also take on embodiments other than those described above. In particular, the device may have features that represent a combination of the respective individual features of the claims.

Reference signs in the claims, the description and the drawings serve only to improve the understanding of the invention and are not intended to limit the scope of protection.

List of reference symbols

1

Display device

2

first, lower e-paper element

3

Display control unit

4

second, upper e-paper element (first variant)

4'

second, upper e-paper element (second variant)

5

TFT active matrix

6

graphic display element

7

Masking display

8

sandwich

8'

sandwich

9

transparent top layer

20

front

22

back

30

Synchronizer

40

inner contour line

42

Frame

44

front

44'

front

46

outline

48

Area that can be switched between transparency and intransparency

60

Display area

61

Part of 60

62

Outer circumference contour

81

first adhesive layer

81'

first adhesive layer

82

second adhesive layer

82'

second adhesive layer

84

cavity

86

transparent filling material

90

Back of 9

A

Eye

B

Viewer

V

Standard viewing direction

QUOTES CONTAINED IN THE DESCRIPTION

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

Cited patent literature

• US 2019/0283686 A1 [0006]
• US 2020/0258478 A1 [0007]
• WO 2021/154418 A1 [0008]

Claims (11)

Display device with a first e-paper element (2) which has at least two types of color pigments and is provided with a TFT active matrix (5) and is designed as a high-resolution bistable matrix display and forms a display element (6), characterized in that on the front side (20) of the first e-paper element (2), which forms a viewing side, a second e-paper element (4; 4') which has at least one type of color pigment is provided, which is provided with transparent electrodes and forms a low-resolution masking display (7). Display device according to Claim 1 , characterized in that the second e-paper element (4') has only one type of color pigment. Display device according to Claim 1 or 2 , characterized in that the first e-paper element (2) and the second e-paper element (4, 4') are designed as flexible display films. Display device according to one of the preceding claims, characterized in that a transparent cover layer (9) is provided on the front side (44; 44') of the second e-paper element (4; 4') forming the viewing side, which cover layer is preferably designed to be flexible. Display device according to one of the preceding claims, characterized in that the TFT active matrix (5) is provided on the rear side of the first e-paper element (2) facing away from the viewing side. Display device according to one of the preceding claims, characterized in that a first adhesive layer (81; 81') is provided between the first e-paper element (2) and the second e-paper element (4, 4'), which adhesive layer bonds both e-paper elements (2, 4; 4') to one another at least in regions. Display device according to Claim 6 , characterized in that the second e-paper element (4') covers the first e-paper element (2) essentially over its entire surface and that both e-paper elements (2, 4') are glued to one another essentially over their entire surface by means of the first adhesive layer (81'). Display device according to Claim 4 and Claim 7 , characterized in that a second adhesive layer (82') is provided between the second e-paper element (4') and the cover layer (9), which adhesive layer bonds the cover layer (9) to the second e-paper element (4') substantially over the entire surface. Display device according to one of the Claims 1 until 6 , characterized in that the second e-paper element (4) covers the first e-paper element (2) only in some areas and that both e-paper elements (2, 4) are glued to one another in the overlapping area by means of the first adhesive layer (81). Display device according to Claim 4 and Claim 9 , characterized in that a second adhesive layer (82) is provided between the second e-paper element (4) and the cover layer (9), which adhesive layer bonds the cover layer (9) to the second e-paper element (4), and in that a transparent filling material (86) is provided between the areas of the first e-paper element (2) not covered by the second e-paper element (4), which adhesive layer bonds the cover layer (9) to the first e-paper element (2). Vehicle, in particular motor vehicle, which is provided on an inner and/or outer surface at least in regions with a display device according to one of the preceding claims.

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