Self-supporting optical film package, backlight, display device and transport means

Abstract

The present invention relates to a self-supporting optical film package (5) for a backlight (3) for a display panel and to a backlight (3) having such a self-supporting optical film package (5). The invention also relates to a display device having such a backlight (3) and to a transport means having such a display device. A self-supporting optical film package (5) according to the invention has a multi-part frame (50) having a first frame part (51) and a second frame part (52). At least one optical film (53) is arranged between the first frame part (51) and the second frame part (52). The first frame part (51) and the second frame part (52) are connected to one another. At least one of the two frame parts (51, 52) has a planar opening (54).

Description

[0001] Description

[0002] Self-supporting optical film package, backlight, display device and means of transport

[0003] The present invention relates to a self-supporting optical film package for a backlight for a display panel, as well as to a backlight comprising such a self-supporting optical film package. The invention also relates to a display device comprising such a backlight, as well as to a means of transportation comprising 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 backlight 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, DE 10 2007 007 353 A1 describes a lighting device with a luminous surface that can be modularly assembled from a plurality of radiation reflectors. Honeycomb-shaped, scale-shaped, triangular, or rectangular radiation reflectors are preferably used. Each of the radiation reflectors has a plurality of radiation-reflecting surfaces that are curved outwardly from a center in which a light source is arranged.

[0007] A matrix backlight for use in a display device has foils or plates above the light sources for light alignment and homogenization. These foils or plates are arranged at a defined distance above the light sources. The foils or plates are supported on a step on the housing, which also houses the circuit board with the light sources. The foils or plates are secured with a frame attached to the housing.

[0008] The step for the support requires installation space at the edges, as it must ensure the foil can be accommodated even under thermal expansion and taking component tolerances into account, and thus must be of appropriate size. Furthermore, the step must be designed outward to allow for easy assembly of the circuit board with the light sources arranged on it.

[0009] The films are individually installed and tested in the matrix backlight housing during final assembly. A separate assembly station is required for each film. The films are delivered with protective films on both sides, which must first be removed during final assembly. Furthermore, the films must be secured in position after each assembly process, e.g., with adhesive tape. This makes final assembly complex.

[0010] Against this background, US 2010 / 0 039 584 A1 describes a multi-piece, self-supporting optical element for a display backlight, comprising a first optical element and a second optical element superimposed on the first optical element. The first optical element and the second optical element are each a rectangular foil or sheet. The two optical elements each have at least two sidewalls on two opposite sides. Optical foils can be arranged between the two optical elements.

[0011] It is an object of the invention to show alternative solutions for the realization of a self-supporting optical film package.

[0012] This object is achieved by a self-supporting optical film package having the features of claim 1, by a background lighting according to claim 8, by a display device according to claim 9, and by a means of transport according to claim 10. Preferred embodiments of the invention are the subject of the dependent claims.

[0013] According to a first aspect of the invention, a self-supporting optical film package for a backlight for a display panel comprises a multi-part frame with a first frame part and a second frame part. At least one optical film is arranged between the first frame part and the second frame part. The first frame part and the second frame part are connected to one another. At least one of the two frame parts has a flat opening.

[0014] In the solution according to the invention, the desired films, e.g., films for light alignment, are pre-assembled as a film package using a frame. The films are arranged between at least two frame parts and secured in position by the frame parts. The step for supporting the films is therefore formed by the lower frame part and can protrude into the backlight housing. The housing can therefore optionally be designed and manufactured in a simpler manner, e.g., as a formed sheet metal. The film package can be connected to the housing in various ways, e.g., using adhesive, adhesive strips, clips, crimping, etc. The frame parts can, for example, be formed from sheet metal or a plastic. The specific choice of material can be made depending in particular on whether further requirements must be met, e.g., with regard to stability, temperature, service life, etc.At least one of the frame parts has a flat opening to allow maximum light transmission. The frame parts can be connected to each other in various ways, e.g., by adhesive, adhesive strips, rivets, clinching (also known as joining or toxing), crimping, screwing, welding, etc.

[0015] By providing the films as a self-supporting optical film package, the number of assembly steps and required resources, as well as the required investment, are significantly reduced. Protective films are no longer required for each film, as the inner films are protected by the outer films. The entire film package can be delivered to the final assembly inspected condition.

[0016] According to one aspect of the invention, at least one of the two frame parts is three-dimensionally shaped. In principle, both frame parts can be substantially flat, but preferably at least one of the two frame parts is three-dimensionally shaped, e.g., to provide space for accommodating a thicker foil stack. However, both frame parts can also be three-dimensionally shaped, whereby the frame parts can be configured symmetrically or asymmetrically.

[0017] According to one aspect of the invention, at least one of the two frame parts is designed to provide light shielding. This has the advantage that additional light shielding elements can be dispensed with if necessary. For example, one of the frame parts can be designed to laterally enclose an optical plate of the self-supporting optical film package.

[0018] According to one aspect of the invention, one of the two frame parts is formed by an optical plate. Since a clear or diffuse optical plate is generally required anyway, this can advantageously serve as one of the two frame parts. In this way, an additional frame part can be eliminated.

[0019] According to one aspect of the invention, at least one of the two frame parts has an additional functional geometry. For example, additional geometries can form locking elements, springs, or elevations, or a hold-down device can be formed that is designed to hold the backlight circuit board in position. For this purpose, the hold-down device can act directly on the circuit board or indirectly via a backlight reflector.

[0020] According to one aspect of the invention, at least one additional functional element is arranged in or on the frame. For example, an additional sealing element can be provided, or noise-reducing elements, such as tapes or felt, can be installed.

[0021] According to one aspect of the invention, the at least one optical film is mounted floatingly between the two frame parts or at least partially firmly connected to at least one of the two frame parts. In a first variant, the films are mounted floatingly between the frame parts. In this way, different thermal expansion of the individual films can be taken into account. Connected films with different thermal expansion could otherwise buckle under temperature stress. In a second variant, individual or all films are connected circumferentially or partially firmly to one or both frame parts. The fastening can be effected by the frame parts or by means such as screws, dowels, etc.

[0022] Preferably, a self-supporting optical film package according to the invention is used in a backlight for a display panel. The backlight is preferably, but not necessarily, a matrix backlight. A housing for the backlight can, for example, be formed from sheet metal or die-cast from non-ferrous metals. Preferably, such a backlight is used in a display device with a display panel.

[0023] A display device according to the invention is preferably used in a means of transport. The means of transport may be, for example, a motor vehicle, but alternatively also an aircraft, a rail vehicle, or a watercraft.

[0024] Further features of the present invention will become apparent from the following description and the appended claims taken in conjunction with the figures.

[0025] Figure overview

[0026] Fig. 1 shows schematically a cross section of a display device according to the prior art;

[0027] Fig. 2 shows schematically a cross section of a first embodiment of a self-supporting optical film package according to the invention;

[0028] Fig. 3 shows a plan view of the self-supporting optical film package of Fig. 2;

[0029] Fig. 4 schematically shows a cross-section through a backlight with the self-supporting optical foil package of Fig. 2; Fig. 5 schematically shows a cross-section of a second embodiment of a self-supporting optical foil package according to the invention;

[0030] Fig. 6 shows schematically a cross-section through a backlight with the self-supporting optical foil package from Fig. 5;

[0031] Fig. 7 shows schematically a cross section of a third embodiment of a self-supporting optical film package according to the invention;

[0032] Fig. 8 shows schematically a cross-section through a backlight with the self-supporting optical foil package from Fig. 7;

[0033] Fig. 9 shows schematically a cross section of a fourth embodiment of a self-supporting optical film package according to the invention;

[0034] Fig. 10 shows schematically a cross-section through a backlight with the self-supporting optical foil package from Fig. 9;

[0035] Fig. 11 shows schematically a cross section of a fifth embodiment of a self-supporting optical film package according to the invention;

[0036] Fig. 12 shows schematically a cross section through a backlight with the self-supporting optical foil package from Fig. 11 ;

[0037] Fig. 13 schematically shows a cross-section through a backlight with a sixth embodiment of a self-supporting optical film package according to the invention; Fig. 14 schematically shows a cross-section through a backlight with a seventh embodiment of a self-supporting optical film package according to the invention;

[0038] Fig. 15 shows schematically a cross section through a backlight with an eighth embodiment of a self-supporting optical film package according to the invention;

[0039] Fig. 16 shows schematically a cross section through a backlight with a ninth embodiment of a self-supporting optical foil package according to the invention; and

[0040] Fig. 17 shows schematically a means of transport that uses a display device according to the invention.

[0041] Character description

[0042] 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.

[0043] Fig. 1 schematically shows a cross-section of a display device 1 according to the prior art. The display device 1 has a display panel 2, which is glued to a cover glass 4. The cover glass 4 seals off a housing 8 of the display device 1 from the environment. A backlight 3 for the display panel 2 is arranged in a further housing 7. The backlight 3 has a reflector 30 with a plurality of cavities 31. A light source 32, typically a light-emitting diode, is arranged in each of the cavities 31. The light sources 32 are arranged on a circuit board 33, which can be glued to the housing 7 of the backlight 3. In the example shown, an optical plate 55 with an optical film stack 6 arranged thereon is located between the backlight 3 and the display panel 2.The films 53 of the optical film stack 6 are designed to scatter, collect, or direct the light from the reflector 30 in such a way that the solid angle requirements of the backlight 3 are met. Typical films 53 for light alignment are brightness enhancement films (BEF) and light control films (LCF). The optical plate 55 is a transparent plate that ensures the optical distance between the optical film stack 6 and the light sources 32. The cover glass 4, the optical plate 55, and the housing 7 of the backlight 3 are connected to one another by suitable connecting elements 9, e.g., adhesives.

[0044] Fig. 2 shows a schematic cross section of a first embodiment of a self-supporting optical film package 5 according to the invention. Fig. 3 shows a plan view of the self-supporting optical film package 5. In this embodiment, the self-supporting optical film package 5 comprises a multi-part frame 50 with a first frame part 51 and a second frame part 52. The frame parts 51, 52 can be formed, for example, from sheet metal or a plastic. An optical plate 55 and a number of optical films 53 are arranged between the first frame part 51 and the second frame part 52. The optical plate 55 and the optical films 53 form a stack and are secured in position by the frame parts 51, 52. The optical plate 55 and the optical films 53 can be mounted floatingly between the two frame parts 51, 52 or at least partially fixedly connected to at least one of the two frame parts 51, 52.The first frame part 51 is essentially flat, whereas the second frame part 52 is three-dimensionally shaped to provide space for accommodating the optical plate 55 and the optical films 53. In the example shown, both frame parts 51, 52 have a flat opening 54 to enable maximum light transmission. At the same time, the second frame part 52 acts as a light barrier. Light emerging laterally from the optical plate 55 is prevented from spreading further. The two frame parts 51, 52 are connected to one another by means of a connecting element 57, here in the form of an adhesive strip. Alternatively, other types of connections can also be realized, e.g., by means of adhesive, rivets, clinching, crimping, screwing, welding, etc.

[0045] Fig. 4 schematically shows a cross-section through a backlight 3 with the self-supporting optical film package 5 from Fig. 2. The self-supporting optical film package 5 is connected to a housing 7 of the backlight 3 by means of a connecting element 9, here in the form of an adhesive strip. Alternatively, a connection by adhesive, clipping, crimping, etc. is also possible. The housing 7 of the backlight 3 can, for example, be made from non-ferrous metals by die-casting. Arranged in the housing 7 in a known manner is a printed circuit board 33 with light sources 32 located thereon, which can, for example, be adhesively bonded to the housing 7. A reflector is not present in this example.

[0046] Fig. 5 shows a schematic cross section of a second embodiment of a self-supporting optical film package 5 according to the invention. Fig. 6 shows a schematic cross section through a backlight 3 with such a self-supporting optical film package 5. The self-supporting optical film package 5 in turn comprises a multi-part frame 50 with a first frame part 51 and a second frame part 52. The two frame parts 51, 52 are connected to one another by means of a connecting element 57, here in the form of an adhesive strip. However, the second frame part 52 in this embodiment is formed by the optical plate 55 on which the optical films 53 are arranged. Therefore, only the first frame part 51, which here too can be formed from sheet metal or a plastic, has a flat opening 54 in order to enable maximum transmission of light.The second frame part 52 is essentially flat, whereas the first frame part 51 is three-dimensionally shaped to provide space for accommodating the optical films 53. In the example shown, the first frame part 51, despite its three-dimensional shape, is not designed to block out the light emerging laterally from the optical plate 55. The self-supporting optical film package 5 is connected to a housing 7 of the backlight 3 by means of a connecting element 9, here in the form of an adhesive strip. Arranged in the housing 7 here again is a printed circuit board 33 with light sources 32 located thereon, which can, for example, be glued to the housing 7. A reflector is not present in this example.

[0047] Fig. 7 shows schematically a cross section of a third embodiment of a self-supporting optical film package 5 according to the invention. Fig. 8 shows schematically a cross section through a background lighting 3 with such a self-supporting optical film package 5. The embodiment shown largely corresponds to that of Fig. 5 and Fig. 6, but the first frame part 51 is designed such that it effects a light shielding for the light emerging laterally from the optical plate 55.

[0048] Fig. 9 schematically shows a cross-section of a fourth embodiment of a self-supporting optical film package 5 according to the invention. Fig. 10 schematically shows a cross-section through a backlight 3 with such a self-supporting optical film package 5. In this embodiment, too, the second frame part 52 is formed by the optical plate 55, which in this case, however, is three-dimensionally shaped. For this purpose, the optical plate 55 can be manufactured, for example, by injection molding. The first frame part 51 is essentially flat.

[0049] Fig. 11 schematically shows a cross-section of a fifth embodiment of a self-supporting optical film package 5 according to the invention. Fig. 12 schematically shows a cross-section through a backlight 3 with such a self-supporting optical film package 5. The embodiment shown largely corresponds to that of Figs. 9 and 10, but the first frame part 51 is designed such that it provides light shielding for the light emerging laterally from the optical plate 55. For this purpose, the first frame part 51 is also three-dimensionally shaped so that it laterally encloses the optical plate 55.

[0050] Fig. 13 shows a schematic cross-section through a backlight 3 with a sixth embodiment of a self-supporting optical film package 5 according to the invention. In this embodiment, the first frame part 51 has an additional functional geometry 56, through which an inwardly angled locking element 58 is formed. After assembly on the housing 7 of the backlight 3, in which case the frame 50 is slipped over the housing 7, the locking element 58 engages in a recess 70 of the housing 7. The self-supporting optical film package 5 is fastened to the housing 7 with a plurality of such locking connections, so that no additional connecting element is required. In this embodiment, the housing 7 is advantageously formed from sheet metal. Furthermore, alternatively or additionally, it is possible to provide locking elements on the housing 7, which engage in corresponding recesses in the frame 50.

[0051] Fig. 14 schematically shows a cross-section through a backlight 3 with a seventh embodiment of a self-supporting optical film package 5 according to the invention. The embodiment shown largely corresponds to that of Fig. 13, except that the frame 50 is inserted into the housing 7 of the backlight 3 during assembly. Therefore, the locking elements 58 are angled outward. Alternatively or additionally, it is again possible to provide locking elements on the housing 7 that engage in corresponding recesses in the frame 50.

[0052] Fig. 15 shows schematically a cross section through a backlight 3 with an eighth embodiment of a self-supporting optical film package 5 according to the invention. The embodiment shown largely corresponds to that of Fig. 14, but in this case the functional geometry 56 not only forms a locking element 58, but also a hold-down device 59. This is designed to hold the circuit board 33 with the light sources 32 located thereon in position.

[0053] Fig. 16 shows schematically a cross section through a backlight 3 with a ninth embodiment of a self-supporting optical film package 5 according to the invention. The embodiment shown largely corresponds to that of Fig. 15, but in this embodiment the hold-down device 59 is designed to hold the circuit board 33 with the light sources 32 located thereon indirectly via a reflector 30 of the backlight 3 in position.

[0054] Fig. 17 schematically shows a means of transport 100 that uses a display device 1 according to the invention. In this example, the means of transport 100 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 101. The sensor system 101 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 101 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 102, by means of which position information can be provided, and a data transmission unit 103. By means of the data transmission unit 103, for example,A connection to a backend can be established, for example, to obtain updated software for components of the motor vehicle. A memory 104 is provided for storing data. Data exchange between the various components of the motor vehicle takes place via a network 105.

[0055] List of reference symbols

[0056] 1 display device

[0057] 2 display panel

[0058] 3 Backlight

[0059] 30 reflector

[0060] 31 Cavity

[0061] 32 light source

[0062] 33 circuit board

[0063] 4 Cover glass

[0064] 5 Self-supporting optical film package

[0065] 50 Multi-part frame

[0066] 51 First frame part

[0067] 52 Second frame part

[0068] 53 Optical film

[0069] 54 Flat opening

[0070] 55 Optical disk

[0071] 56 Functional Geometry

[0072] 57 Connecting element

[0073] 58 locking element

[0074] 59 hold-down clamps

[0075] 6 stacks of slides

[0076] 7 Backlight housing

[0077] 70 recess

[0078] 8 Housing of the display device

[0079] 9 Connecting element

[0080] 100 means of transport

[0081] 101 Sensor Technology

[0082] 102 Navigation system

[0083] 103 Data transmission unit

[0084] 104 Storage 105 Network

Claims

Patent claims 1. Self-supporting optical film package (5) for a background lighting (3) for a display panel (2), with a multi-part frame (50) with a first frame part (51) and a second frame part (52), and with at least one optical film (53) arranged between the first frame part (51) and the second frame part (52), wherein the first frame part (51) and the second frame part (52) are connected to one another and at least one of the two frame parts (51, 52) has a flat opening (54).

2. Self-supporting optical film package (5) according to claim 1, wherein at least one of the two frame parts (51, 52) is three-dimensionally shaped.

3. Self-supporting optical film package (5) according to claim 1 or 2, wherein at least one of the two frame parts (51, 52) is designed to provide light shielding.

4. Self-supporting optical film package (5) according to one of the preceding claims, wherein one of the two frame parts (51, 52) is formed by an optical plate (55).

5. Self-supporting optical film package (5) according to one of the preceding claims, wherein at least one of the two frame parts (51, 52) has an additional functional geometry (56).

6. Self-supporting optical film package (5) according to one of the preceding claims, wherein at least one additional functional element is arranged in or on the frame (50).

7. Self-supporting optical film package (5) according to one of the preceding claims, wherein the at least one optical film (53) is floating between the two frame parts (51, 52) or is at least partially fixedly connected to at least one of the two frame parts (51, 52).

8. Backlight (3) for a display panel (2), wherein the backlight (3) comprises a self-supporting optical film package (5) according to one of claims 1 to 7.

9. Display device (1) with a display panel (2), wherein the display device (1) has a backlight (3) according to claim 8.

10. Means of transport (100) with a display device (1) according to claim 9.

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