Display device and transport means

Abstract

The invention relates to a display device (1) and to transport means comprising a display device (1) of this type. The display device (1) has a curved display panel (2) and a backlight (3) for the display panel (2). The backlight (3) has at least one flat circuit board (4) with a plurality of light sources (32) and a reflector (30) with a plurality of reflective cavities (31). At least one of the light sources (32) is arranged in each of the cavities (31). An underside (300) of the reflector (30) is flat, while an upper side (301) of the reflector (30) is adapted to the curvature of the display panel (2).

Description

[0001] Description

[0002] Display device and means of transport

[0003] The present invention relates to a display device, in particular a display device with a curved display panel, and a means of transport with such a display device.

[0004] The number and area of ​​display devices in vehicles are constantly increasing. Display devices can be found on the market, for example, as instrument clusters for the driver, as central displays, and even as passenger displays. Non-self-luminous transmissive displays require backlighting to display the image. The purpose of the backlighting is to illuminate the display panel as evenly as possible across the entire active area, creating the most homogeneous display possible right up to the edges.

[0005] Matrix backlights use a multitude of light sources arranged in a matrix to generate light. A reflector directs the light from the light sources toward the display panel.

[0006] For example, US 2010 / 0141867 A1 describes a planar light-emitting device comprising a reflector with an upper surface, a separating element arranged on the reflector, a plurality of light sources, and a diffusion plate. The reflector serves as a light-reflecting surface. The separating element forms a plurality of cavities, in each of which the light sources are arranged. The diffusion plate is held at the upper edges of the separating element. The side surfaces of the separating element, which bound the cavities, are light-reflecting surfaces. Curved display devices are increasingly being used, i.e. display devices whose surface is not, or at least not completely flat, but has a curvature. This curvature can serve, for example, to increase the immersion of a viewer or to adapt the shape of the display device to an installation environment, e.g. in a means of transport.

[0007] For example, JP 2016 - 066 085 A describes a display device with a curved display surface. The display device comprises a number of adjacent display modules.

[0008] One challenge with curved displays with matrix backlighting is that the circuit boards containing the light sources arranged in a matrix must be contoured to the curved shape of the display to ensure homogeneous illumination with a parallel spacing. This requires bending the circuit boards, which creates stresses that extend into the solder joints of the lighting components, such as the LEDs and their associated drivers. These stresses negatively impact the lifetime of the connection or component.

[0009] It is an object of the invention to provide an improved display device with a curved display panel and a matrix backlight.

[0010] This object is achieved by a display device having the features of claim 1 and by a means of transport according to claim 9. Preferred embodiments of the invention are the subject of the dependent claims. According to a first aspect of the invention, a display device comprises a curved display panel and a backlight for the display panel, wherein the backlight comprises:

[0011] - at least one flat circuit board with a plurality of light sources; and

[0012] - a reflector having a plurality of reflective cavities, in each of which at least one of the light sources is arranged, wherein a bottom side of the reflector is flat and a top side of the reflector is adapted to the curvature of the display panel.

[0013] The inventive solution uses a reflector with a flat underside, which follows the shape or curvature of the display panel on the top side. At least one flat circuit board with the required light sources is located on the underside. The inventive solution thus allows the use of flat circuit boards. The use of non-curved circuit boards is more cost-effective and more reliable in terms of service life.

[0014] Furthermore, handling during production is also easier. The reflector is preferably made of plastic or an elastomer, e.g., polycarbonate with an admixture of titanium dioxide for the desired reflectivity.

[0015] According to one aspect of the invention, the upper side of the reflector follows the curvature of the display panel or is approximated to the curvature of the display panel. If the upper side is precisely adapted to the curvature of the display panel, a consistently very small distance between the reflector and the display panel can be achieved. However, an exact adaptation may be more complex to manufacture. Approximating the shape of the upper side to the curvature of the display panel, for example by having the walls of the cavities each have a straight upper end, is easier to implement. According to one aspect of the invention, the upper side of the reflector is convex, concave, partially convex and concave, or partially flat. The specific design of the reflector depends on the shape of the display panel, i.e. on the desired design of the display device.

[0016] According to one aspect of the invention, the density of the light sources varies across the surface of the at least one planar printed circuit board. In principle, the light sources can be spaced at constant distances, but for homogeneous illumination, it is advantageous to use variable distances. For example, if the distance between the light source and the display panel is large, the light sources can be placed closer together to increase the luminance.

[0017] According to one aspect of the invention, the light sources are controlled or designed such that the illuminance of the light sources varies across the surface of the at least one planar printed circuit board. Alternatively, or in addition to varying the density of the light sources across the surface, it is also possible to adjust the illuminance of the light sources across the surface in a controlled manner to achieve homogeneous illumination of the display panel. For example, light sources with different maximum luminous outputs are arranged at different locations on the printed circuit board, or light sources with the same maximum luminous outputs are controlled differently. A combination of both measures is also possible.

[0018] According to one aspect of the invention, the display device has a plurality of flat circuit boards in a spatial arrangement, each with a plurality of light sources. The spatial arrangement of the circuit boards makes it possible to save installation space. Furthermore, further shapes of the display panel are enabled. A spatial arrangement of the circuit boards here means that the circuit boards are not all located in one plane, but in different planes. These planes can be parallel to one another or inclined. According to one aspect of the invention, the reflector has a modular design. The individual modules preferably each have a circuit board with light sources arranged thereon and a reflector element. The use of modules has the advantage that the reflector is composed of smaller elements that are easier to manufacture and handle. In particular, the tolerances are smaller.The required production tools are also smaller, allowing them to be manufactured more quickly and expanding the pool of manufacturers capable of manufacturing them. Furthermore, the modules can be used for differently designed display devices, which is often not possible with a single-piece reflector. Preferably, there is a gap between adjacent modules. This gap allows the modules to expand without the adjacent modules colliding, which could cause stress and deformation. For example, a gap of approximately 0.3 mm can be provided between the modules.

[0019] According to one aspect of the invention, the walls of the cavities are parabolic or at least partially rounded, and the cavities are designed to reflect the light emitted by the light sources toward the display panel. Due to the parabolic shape or the at least partial rounding, the emitted light can be reflected more specifically toward the display panel. The light sources are preferably side-emitting light-emitting diodes, in particular light-emitting diodes that emit light from all sides. The use of side-emitting light-emitting diodes has the advantage of preventing the formation of light spots in the backlight. This ensures particularly homogeneous illumination of the display panel.

[0020] A display device according to the invention is preferably used in a means of transportation. The means of transportation can be, for example, a motor vehicle, but alternatively also an aircraft, a rail vehicle, or a watercraft. Further features of the present invention will become apparent from the following description and the appended claims in conjunction with the figures.

[0021] Figure overview

[0022] Fig. 1 shows schematically a first embodiment of a display device according to the invention with a concave display panel;

[0023] Fig. 2 shows schematically a second embodiment of a display device according to the invention with a concave display panel;

[0024] Fig. 3 shows schematically a third embodiment of a display device according to the invention with a concave display panel;

[0025] Fig. 4 shows schematically a fourth embodiment of a display device according to the invention with a concave display panel;

[0026] Fig. 5 shows schematically a fifth embodiment of a display device according to the invention with a concave display panel;

[0027] Fig. 6 schematically shows a first embodiment of a display device according to the invention with a convex display panel; Fig. 7 schematically shows a second embodiment of a display device according to the invention with a convex display panel;

[0028] Fig. 8 shows schematically a third embodiment of a display device according to the invention with a convex display panel;

[0029] Fig. 9 shows schematically a fourth embodiment of a display device according to the invention with a convex display panel;

[0030] Fig. 10 shows schematically a fifth embodiment of a display device according to the invention with a convex display panel;

[0031] Fig. 11 shows schematically a first embodiment of a display device according to the invention with a display panel with a partially convex and concave curvature;

[0032] Fig. 12 shows schematically a second embodiment of a display device according to the invention with a display panel with a partially convex and concave curvature;

[0033] Fig. 13 shows schematically an embodiment of a display device according to the invention with a partially flat display panel; and

[0034] Fig. 14 schematically shows a means of transport that uses a display device according to the invention.

[0035] To better understand the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. Like reference numerals are used in the figures for like or equivalent elements and are not necessarily described again for each figure. It is understood that the invention is not limited to the illustrated embodiments and that the described features can also be combined or modified without departing from the scope of the invention as defined in the appended claims.

[0036] Fig. 1 schematically shows a first embodiment of a display device 1 according to the invention with a concave display panel 2. A section through the display device 1 is shown. The display device 1 has a backlight 3 for the display panel 2. The backlight 3 has a flat circuit board 4 with a plurality of light sources 32 and a reflector 30 with a plurality of reflective cavities 31. One of the light sources 32 is arranged in each of the cavities 31. A bottom side 300 of the reflector 30 is flat, whereas a top side 301 of the reflector 30 is adapted to the curvature of the display panel 2. The reflector 30 can be made, for example, of plastic or an elastomer, e.g. of polycarbonate with an admixture of titanium dioxide for the desired reflectivity.The cavities 31 are partially rounded to reflect the light emitted by the light sources 32 toward the display panel 2. In this embodiment, the light sources 32 have a constant spacing across the surface of the circuit board 4. In the example shown, an optical film stack 5 is located between the backlight 3 and the display panel 2. The films of the optical film stack 5 have the task of scattering, collecting, or directing the light from the reflector 30 in such a way that the requirements for the solid angle of the backlight 3 are met. Typical films for light alignment are brightness enhancement films (BEF) and light control films (LCF).

[0037] Fig. 2 schematically shows a second embodiment of a display device 1 according to the invention with a concave display panel 2. Shown is a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 1. However, the light sources 32 have a variable spacing across the surface of the circuit board 4. In this example, the density of the light sources 32 is greater in the center of the display device 1 than at the edge of the display device 1. For homogeneous illumination of the display panel 2, the illuminance of the light sources 32 can be adjusted in a controlled manner across the surface of the circuit board 4 if required. Furthermore, the cavities 31 in the example shown are not rounded, but have straight, inclined walls.

[0038] Fig. 3 schematically shows a third embodiment of a display device 1 according to the invention with a concave display panel 2. Shown is a section through the display device 1. The embodiment largely corresponds to the embodiment shown in Fig. 1. However, the reflector 30 in this embodiment has a modular design. The individual modules 33 each have a circuit board 4 with light sources 32 arranged thereon and a reflector element 34. The use of modules 33 has the advantage that the reflector 30 is composed of smaller elements that are easier to manufacture and handle. In the example shown, there is a free space 35 between adjacent modules 33. The free space 35 enables the modules 33 to expand without the adjacent modules 33 colliding with one another and resulting in stresses and deformations.In the example shown, the cavities 31 are not rounded, but have straight, inclined walls. The inclination of the walls is selected such that a primary direction of the emitted light runs perpendicular to the display panel 2.

[0039] Fig. 4 schematically shows a fourth embodiment of a display device 1 according to the invention with a concave display panel 2. Shown is a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 3. The reflector 30 is again of modular construction. The individual modules 33 each have a circuit board 4 with light sources 32 arranged thereon, as well as a reflector element 34. However, the various circuit boards 4 are arranged spatially, i.e., they lie in different, mutually parallel planes. The spatial arrangement of the various circuit boards 4 saves installation space.

[0040] Fig. 5 schematically shows a fifth embodiment of a display device 1 according to the invention with a concave display panel 2. It shows a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 4. The reflector 30 is again modular in design, but the various circuit boards 4 of the modules 33 lie in planes inclined relative to one another. This is particularly advantageous when the display panel has a pronounced curvature.

[0041] In the embodiments shown in Fig. 4 and Fig. 5, the reflector 30 has a modular design. However, this is not mandatory. The reflector 30 can also be formed in one piece. In this case, the underside 300 of the reflector 30 is flat in sections.

[0042] Fig. 6 schematically shows a first embodiment of a display device 1 according to the invention with a convex display panel 2. It shows a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 1, except that the display panel 2 in this case is convex rather than concave. As in the embodiment in Fig. 1, the cavities 31 are partially rounded in order to reflect the light emitted by the light sources 32 toward the display panel 2. Furthermore, the light sources 32 are spaced at a constant distance across the surface of the circuit board 4.

[0043] Fig. 7 schematically shows a second embodiment of a display device 1 according to the invention with a convex display panel 2. Shown is a section through the display device 1. The embodiment largely corresponds to the embodiment shown in Fig. 6. However, the light sources 32 have a variable spacing across the surface of the circuit board 4. In this example, the density of the light sources 32 is lower in the center of the display device 1 than at the edge of the display device 1. For homogeneous illumination of the display panel 2, the illuminance of the light sources 32 can be adjusted in a controlled manner across the surface of the circuit board 4 if necessary. Furthermore, the cavities 31 in the example shown are not rounded, but have straight, inclined walls.

[0044] Fig. 8 schematically shows a third embodiment of a display device 1 according to the invention with a convex display panel 2. It shows a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 6. However, the reflector 30 in this embodiment has a modular design. The individual modules 33 each have a circuit board 4 with light sources 32 arranged thereon, as well as a reflector element 34. In the example shown, there is a free space 35 between adjacent modules 33. The free space 35 allows the modules 33 to expand without the adjacent modules 33 colliding with one another, which could lead to stresses and deformations. In the example shown, the cavities 31 are not rounded, but have straight, inclined walls. Fig. 9 schematically shows a fourth embodiment of a display device 1 according to the invention with a convex display panel 2.Shown is a section through the display device 1. The embodiment largely corresponds to the embodiment shown in Fig. 8. The reflector 30 is again of modular construction. The individual modules 33 each comprise a circuit board 4 with light sources 32 arranged thereon, as well as a reflector element 34. However, the various circuit boards 4 are spatially arranged, i.e., they lie in different, mutually parallel planes.

[0045] Fig. 10 schematically shows a fifth embodiment of a display device 1 according to the invention with a convex display panel 2. It shows a section through the display device 1. This embodiment largely corresponds to the embodiment shown in Fig. 9. The reflector 30 is again of modular construction, but the various circuit boards 4 of the modules 33 are arranged in planes inclined relative to one another.

[0046] In the embodiments shown in Fig. 9 and Fig. 10, the reflector 30 has a modular design. However, this is not mandatory. The reflector 30 can also be formed in one piece. In this case, the underside 300 of the reflector 30 is flat in sections.

[0047] Fig. 11 schematically shows a first embodiment of a display device 1 according to the invention, comprising a display panel 2 with a partially convex and concave curvature. In this case, too, a bottom side 300 of the reflector 30 is flat, whereas a top side 301 of the reflector 30 is adapted to the curvature of the display panel 2.

[0048] Fig. 12 schematically shows a second embodiment of a display device 1 according to the invention, comprising a display panel 2 with a partially convex and concave curvature. In this embodiment, the reflector 30 has a modular design. The individual modules 33 each comprise a circuit board 4 with light sources 32 arranged thereon, as well as a reflector element 34. In the example shown, a free space 35 is located between adjacent modules 33 to prevent stresses and deformations in the event of expansion of the modules 33.

[0049] Of course, the aspects illustrated by the various embodiments can be combined if required.

[0050] Fig. 13 schematically shows an embodiment of a display device 1 according to the invention with a partially flat display panel 2. In this example, only the edge regions of the display panel 2 are convexly curved, whereas the central region of the display panel 2 has no curvature. In this case, too, a bottom side 300 of the reflector 30 is flat, while a top side 301 of the reflector 30 is adapted to the curvature of the display panel 2.

[0051] Fig. 14 schematically shows a means of transport 20 that uses a display device 1 according to the invention. In this example, the means of transport 20 is a motor vehicle. The motor vehicle has a display device 1 according to the invention, which is arranged in a dashboard. Data on the vehicle's surroundings can be acquired using a sensor system 21. The sensor system 21 can, in particular, comprise sensors for environmental detection, e.g., ultrasonic sensors, laser scanners, radar sensors, lidar sensors, or cameras. The information acquired by the sensor system 21 can be used to generate content to be displayed for the display device 1. Further components of the motor vehicle in this example are a navigation system 22, by means of which position information can be provided, and a data transmission unit 23. By means of the data transmission unit 23, for example,A connection to a backend can be established, for example, to obtain updated software for components of the motor vehicle. A memory 24 is provided for storing data. Data exchange between the various components of the motor vehicle takes place via a network 25.

[0052] List of reference symbols

[0053] 1 display device

[0054] 2 display panel

[0055] 3 Backlight

[0056] 30 reflector

[0057] 300 subpage

[0058] 301 top

[0059] 31 Cavity

[0060] 32 light source

[0061] 33 Module

[0062] 34 Reflector element

[0063] 35 free space

[0064] 4 circuit board

[0065] 5 stacks of slides

[0066] 20 means of transport

[0067] 21 Sensor technology

[0068] 22 Navigation system

[0069] 23 Data transmission unit

[0070] 24 storage

[0071] 25 Network

Claims

Patent claims 1 . Display device (1 ) with a curved display panel (2) and a backlight (3) for the display panel (2), wherein the backlight (3) comprises: - at least one flat circuit board (4) with a plurality of light sources (32); and - a reflector (30) having a plurality of reflective cavities (31), in each of which at least one of the light sources (32) is arranged, wherein a bottom side (300) of the reflector (30) is flat and a top side (301) of the reflector (30) is adapted to the curvature of the display panel (2).

2. Display device (1) according to claim 1, wherein the upper side (301) of the reflector (30) follows the curvature of the display panel (2) or is approximated to the curvature of the display panel (2).

3. Display device (1) according to claim 1 or 2, wherein the upper side (301) of the reflector (30) is convex, concave, partially convex and concave or partially flat.

4. Display device (1) according to one of the preceding claims, wherein a density of the light sources (32) varies over the area of ​​the at least one planar circuit board (4).

5. Display device (1) according to one of the preceding claims, wherein the light sources (32) are controlled or designed such that an illuminance of the light sources (32) varies over the area of ​​the at least one flat printed circuit board (4).

6. Display device (1) according to one of the preceding claims, wherein the display device (1) comprises a plurality of planar printed circuit boards (4) in a spatial arrangement, each with a plurality of light sources (32).

7. Display device (1) according to one of the preceding claims, wherein the Reflector (30) is modular.

8. Display device (1) according to one of the preceding claims, wherein walls (34) of the cavities (31) are parabolic or at least partially rounded and the cavities (31) are designed to reflect the light emitted by the light sources (32) in the direction of the display panel (2).

9. Means of transport (20) with a display device (1) according to one of the preceding claims.

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