Backlight module and display device

Abstract

The utility model relates to the technical field of display, particularly provides a backlight module and a display device, and aims to solve the problem that the local brightness of an existing display device is not uniform. In order to achieve the purpose, the backlight module comprises a back plate, the back plate is provided with a bottom wall and a side wall connected with the bottom wall, and a containing space is formed between the bottom wall and the side wall; the optical film set is arranged in the containing space, the optical film set comprises a light guide plate, and the light guide plate is provided with a first surface facing the bottom wall and a light incident surface facing the side wall; the light-emitting assembly comprises a flexible circuit board fixed to the first surface and a light source connected to the flexible circuit board, and the light-emitting face of the light source faces the light-in face; the end, close to the light-emitting assembly, of the bottom wall is provided with a sinking groove, and the flexible circuit board is attached to the bottom face of the sinking groove. According to the display device, the possibility that the flexible circuit board is wrinkled can be reduced, then the problem of uneven brightness caused by the light leakage phenomenon is solved, and the image quality of the display device is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and specifically provides a backlight module and a display device. Background Art

[0002] Liquid crystal display is a widely used display device, in which the backlight module is an important component of the liquid crystal display and is used to provide light source for the liquid crystal display. With the development of display technology, the performance requirements for liquid crystal displays are getting higher and higher. However, it is found in actual applications that the current display devices still have the phenomenon of uneven brightness in some parts. Utility Model Content

[0003] The present application aims to solve the above technical problem, that is, to solve the problem of uneven brightness in some parts of the existing display device.

[0004] In a first aspect, the present application provides a backlight module, comprising:

[0005] A back plate, comprising a bottom wall and a side wall connected to the bottom wall, wherein a receiving space is formed between the bottom wall and the side wall;

[0006] An optical film set, which is arranged in the accommodation space, and the optical film set includes a light guide plate, and the light guide plate has a first surface facing the bottom wall and a light incident surface facing the side wall;

[0007] A light emitting component, comprising a flexible circuit board fixed to the first surface and a light source connected to the flexible circuit board, wherein a light emitting surface of the light source faces the light incident surface;

[0008] A sinking groove is formed at one end of the bottom wall close to the light emitting component, and the flexible circuit board is in contact with the bottom surface of the sinking groove.

[0009] In a technical solution of the above backlight module, the light emitting component further includes:

[0010] An adhesive layer is respectively bonded and fixed to the first surface and the flexible circuit board.

[0011] In a technical solution of the above backlight module, the adhesive layer includes a first adhesive layer and a second adhesive layer bonded to the first adhesive layer, the first adhesive layer is bonded to the first surface, and the second adhesive layer is bonded to the flexible circuit board;

[0012] The first adhesive layer is made of a transparent material, and the second adhesive layer has a reflective surface facing the first adhesive layer, and the reflective surface is used to reflect the light entering the light guide plate.

[0013] In a technical solution of the above backlight module, a plurality of light sources are arranged on the flexible circuit board along the extension direction of the light incident surface, a plurality of first adhesive layers are arranged, and each of the first adhesive layers is located between adjacent light sources;

[0014] The second adhesive layer is integrally arranged and connected to the first adhesive layers.

[0015] In a technical solution of the above backlight module, the sum of the thicknesses of the flexible circuit board and the adhesive layer in a natural state is greater than the distance from the first surface to the bottom surface of the sink.

[0016] In a technical solution of the above backlight module, a reinforcing plate or a covering film is provided on the surface of the flexible circuit board facing away from the light guide plate.

[0017] In a technical solution of the above backlight module, a mesh structure is arranged in an area of ​​the flexible circuit board outside its metal wiring area.

[0018] In a technical solution of the above backlight module, the depth of the sinking groove is 0.05-0.08 mm.

[0019] In a second aspect, the present application provides a display device, comprising a display panel and a backlight module according to any one of the first aspects.

[0020] In a technical solution of the above-mentioned display device, the display device has a display area, a preset line of sight located at the boundary of the display area forms an intersection with the first surface of the light guide plate, and the distance from the end of the glue layer away from the light source to the boundary of the display area is greater than the distance from the intersection to the boundary of the display area.

[0021] In a technical solution of the above display device, the angle between the preset line of sight and the light emitting surface of the display panel is less than or equal to 45°.

[0022] In a technical solution of the above display device, the difference between the distance from the end of the adhesive layer away from the light source to the border of the display area and the distance from the intersection to the border of the display area is 0.2-0.3 mm.

[0023] In the case of adopting the above-mentioned technical solution, the present application increases the thickness of the flexible circuit board by opening a groove on the back panel for accommodating the flexible circuit board. When the thickness of the flexible circuit board increases, its rigidity is better, thereby increasing the ability of the flexible circuit board to resist tensile stress or shear stress. Therefore, when the ambient temperature fluctuates or the light guide plate expands and contracts, the possibility of wrinkles on the flexible circuit board is reduced, thereby improving the problem of uneven brightness caused by light leakage and improving the picture quality of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, in which:

[0025] Figure 1 It is a partial schematic diagram of a backlight module in a normal state in the prior art;

[0026] Figure 2 It is a partial schematic diagram of a backlight module in an abnormal state in the prior art;

[0027] Figure 3 is a longitudinal cross-sectional schematic diagram of a backlight module according to an embodiment of the present application;

[0028] Figure 4 Yes Figure 3 Left view after the mid-back panel is hidden;

[0029] Figure 5 is a schematic diagram of the internal structure of a flexible circuit board according to an embodiment of the present application;

[0030] Figure 6 is a schematic longitudinal cross-sectional view of a display device according to an embodiment of the present application.

[0031] In the figures, the reference numerals refer to the following:

[0032] 1. back plate; 11. bottom wall; 111. sink; 12. side wall; 2. optical film group; 21. light guide plate; 211. light incident surface; 22. reflective film; 3. light emitting component; 31. flexible circuit board; 311. metal wiring area; 312. mesh structure; 32. light source; 33. adhesive layer; 331. first adhesive layer; 332. second adhesive layer; 4. display panel;

[0033] 100, light guide plate; 200, light bar; 300, flexible circuit board; 400, adhesive layer; 500, display area; 501, preset line of sight. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application and are not used to limit the scope of protection of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0035] It should be noted that in the description of this application, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the relevant devices or components must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application. In addition, the ordinal numbers "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] Reference Figure 1 , is a partial schematic diagram of a backlight module in a normal state in the prior art, Figure 2 The backlight module of the display device includes a light guide plate 100, a light bar 200, and a flexible circuit board 300 electrically connected to the light bar 200. The flexible circuit board 300 is responsible for providing power to the light bar 200 so that the light bar 200 emits light. The flexible circuit board 300 is bonded and fixed to the light guide plate 100 by an adhesive layer 400.

[0038] In the actual application of the display device, when the light guide plate 100 expands or contracts due to the influence of temperature, a relative displacement will occur between the light guide plate 100 and the light bar 200, which will increase the gap between the light incident surface of the light guide plate 100 and the light emitting surface of the light bar 200, resulting in light leakage, thereby reducing the incident light energy and darkening the display device screen.

[0039] On the other hand, since the hygroscopic expansion rate of the light guide plate 100 is much greater than that of the flexible circuit board 300, the expansion rates of the two are inconsistent. After the flexible circuit board 300 and the light guide plate 100 are bonded by glue and a glue layer 400 is formed between the two, the light guide plate 100 will force the flexible circuit board 300 to expand. When the light guide plate 100 shrinks and recovers to its original state again, the flexible circuit board 300 may cause irreversible deformation due to exceeding its own expansion limit, thereby causing the flexible circuit board 300 to be wrinkled. When the flexible circuit board 300 is wrinkled, the following will occur: Figure 2As shown in the phenomenon, the flexible circuit board 300 cannot fit tightly with the light guide plate 100 and the back plate of the backlight module. Accordingly, the light emitting surface of the light bar 200 will also be inclined relative to the light emitting surface of the light guide plate 100, and light leakage will occur on the upper and lower sides of the light bar 200. Based on the wavy wrinkled state of the flexible circuit board 300, spaced bright and dark bands will be formed along the light incident part, presenting an uneven brightness phenomenon.

[0040] Reference Figure 3 , is a schematic longitudinal cross-sectional view of a backlight module according to an embodiment of the present application. The backlight module includes a back plate 1, an optical film group 2 and a light-emitting component 3.

[0041] The back plate 1 specifically includes a bottom wall 11 and a side wall 12. The side wall 12 is arranged around the edges of the bottom wall 11. The side wall 12 and the bottom wall 11 define a storage space, and the optical film group 2 and the light-emitting component 3 are both arranged in the storage space. In some implementations, the bottom wall 11 and the side wall 12 can be an integrally formed part, for example, the bottom wall 11 and the side wall 12 are made by stamping.

[0042] The optical film group 2 includes a light guide plate 21 fixed to the bottom wall 11. For the convenience of expression, the surface of the light guide plate 21 facing the bottom wall 11 is called the first surface, and the surface opposite to the first surface is called the second surface. It can be seen that the light is continuously reflected between the first surface and the second surface in the light guide plate 21 and finally emitted from the second surface.

[0043] In some embodiments, the optical film group 2 also includes a reflective film 22 arranged between the first surface and the bottom wall 11, and optical films such as a diffusion film and a prism film arranged on the second surface, wherein the reflective film 22 is used to reflect the light passing through the first surface back into the light guide plate 21, and optical films such as the diffusion film and the prism film are used to improve the scattering effect of light, etc.

[0044] The light emitting component 3 includes a flexible circuit board 31, a light source 32 and an adhesive layer 33. The light source 32 is fixed on the flexible circuit board 31 and electrically connected to the flexible circuit board 31, wherein the light guide plate 21 has a light incident surface 211, the light incident surface 211 is respectively connected to the first surface and the second surface, and the light emitting surface of the light source 32 faces the light incident surface 211, that is, the light source 32 of the present application is a side-entry light source. The adhesive layer 33 is respectively bonded and fixed to the first surface and the flexible circuit board 31, thereby fixing the light emitting surface of the light source 32 relative to the light incident surface 211.

[0045] A sinking groove 111 is provided at one end of the bottom wall 11 close to the light emitting component 3, and the surface of the side of the flexible circuit board 31 away from the adhesive layer 33 is closely attached to the bottom surface of the sinking groove 111. It should be noted that the sinking groove 111 is only used to accommodate the flexible circuit board 31, and the cross-sectional dimensions of the sinking groove 111 should not affect the formation or setting of the reflective film 22. Optionally, the depth of the sinking groove 111 is set to 0.05-0.08mm, and the depth of the sinking groove 111 is controlled within the above range. Under the premise of increasing the thickness of the flexible circuit board 31, it can also prevent the structural strength of the back plate 1 from being affected by the excessive depth of the sinking groove 111.

[0046] The present application increases the thickness of the flexible circuit board 31 by providing a groove 111 on the back plate 1 for accommodating the flexible circuit board 31. When the thickness of the flexible circuit board 31 increases, its rigidity is better, thereby increasing the ability of the flexible circuit board 31 to resist tensile stress or shear stress. Therefore, when the ambient temperature fluctuates or the light guide plate 21 expands and contracts, the possibility of wrinkles on the flexible circuit board 31 is reduced, thereby improving the problem of uneven brightness caused by light leakage and improving the picture quality of the display device.

[0047] Reference Figure 3 and Figure 4 In some embodiments, a plurality of light sources 32 are arranged at intervals along the extension direction of the light incident surface 211 of the light guide plate 21. The adhesive layer 33 includes a first adhesive layer 331 and a second adhesive layer 332, wherein the first adhesive layer 331 is a double-sided adhesive, one side surface of which is bonded and fixed to the first surface of the light guide plate 21, and the other side surface is bonded and fixed to the second adhesive layer 332, and the second adhesive layer 332 can be a single-sided adhesive layer, and when the second adhesive layer 332 is a single-sided adhesive layer, its adhesive surface is bonded and fixed to the flexible circuit board 31.

[0048] The first adhesive layer 331 is a transparent material, and is made of a material with high adhesion and high weather resistance. Weather resistance refers to the ability of the first adhesive layer 331 to resist harsh environments, such as high and low temperatures, high humidity, and other environmental conditions. Thus, when the first adhesive layer 331 has high adhesion, the adhesion between it and the first surface of the light guide plate 21 is stronger, which can reduce the probability of displacement of the first adhesive layer 331 in the extension direction of the light incident surface 211 due to expansion and contraction of the light guide plate 21, thereby preventing the glue particles from overflowing to the front of the light emitting surface of the light source 32, thus reducing the phenomenon of bright spots caused by the glue particles blocking the light path.

[0049] The second adhesive layer 332 has a reflective surface facing the first adhesive layer 331. Since the first adhesive layer 331 is made of a transparent material, the reflective surface formed by the second adhesive layer 332 can reflect the light passing through the first adhesive layer 331 into the light guide plate 21, thereby increasing the utilization rate of the light and the light output quality. In some implementations, the second adhesive layer 332 can be a white film layer as a whole, and the white film layer naturally forms the above-mentioned reflective surface to achieve reflection of the light.

[0050] Optionally, a plurality of first adhesive layers 331 are arranged at intervals, and each first adhesive layer 331 is located between adjacent light sources 32, that is, the first adhesive layers 331 and the light sources 32 are arranged alternately along the extension direction of the light incident surface 211. The number of the second adhesive layer 332 is one, and the second adhesive layer 332 is an integrated belt-shaped structure that is consistent with the extension direction of the light incident surface 221. The second adhesive layer 332 is connected to each first adhesive layer 331, so as to enhance the integrity of the backlight module.

[0051] In one embodiment of the present application, the sum of the thicknesses of the flexible circuit board 31, the first adhesive layer 331 and the second adhesive layer 332 in a natural state is greater than the distance from the first surface of the light guide plate 21 to the bottom surface of the groove 111, so that after the light-emitting component 3, the light guide plate 21 and the back plate 1 are assembled, the flexible circuit board 31, the first adhesive layer 331 and the second adhesive layer 332 are compressed, and the bottom surface of the groove 111 generates an extrusion force perpendicular to the plane where the light guide plate 21 is located on the flexible circuit board 31, thereby further reducing the possibility of the flexible circuit board 31 being wrinkled due to external stress.

[0052] In one embodiment of the present application, a reinforcing plate or a covering film is further provided on the surface of the flexible circuit board 31 facing away from the light guide plate 21. The reinforcing plate or the covering film covers the entire surface of the flexible circuit board 31. For example, the covering film can be made of an insulating material such as a PI film (polyimide film), and the reinforcing plate can be composited by multiple layers of covering films.

[0053] The covering film or reinforcing plate is provided to enhance the rigidity of the flexible circuit board 31, thereby further increasing the ability of the flexible circuit board 31 to resist tensile stress or shear stress, and reducing the possibility of wrinkles on the flexible circuit board 31 when subjected to the above stress.

[0054] Reference Figure 5, is a schematic diagram of the internal structure of a flexible circuit board according to an embodiment of the present application. A metal wiring area 311 is provided on the flexible circuit board 31, and a mesh structure 312 is provided in the area outside the metal wiring area 311 on the flexible circuit board 31. The mesh structure 312 can be a metal wire mesh or a metal plate with holes, and the present application does not limit its specific form. The mesh structure 312 can be embedded in the slot of the flexible circuit board 31, or fixedly connected to the flexible circuit board 31. The mesh structure 312 can not only reduce the overall weight of the flexible circuit board 31, but also the structural characteristics of the mesh structure 312 itself make it have higher rigidity than the solid structure, thereby further improving the overall rigidity of the flexible circuit board.

[0055] Reference Figure 6 The present application also discloses a display device, which includes a display panel 4 and a backlight module in any of the above embodiments. The display panel 4 is installed on the light-emitting side of the backlight module, and the display panel may include a light-shielding adhesive layer, a lower polarizer, a liquid crystal panel, an upper polarizer, an optical adhesive layer, and a cover plate, etc., which are arranged in sequence along the light-emitting direction. Among them, the light-shielding adhesive layer is used to connect the upper prism film and the lower polarizer, and the optical adhesive layer is used to connect the upper polarizer and the cover plate. Of course, the display panel 4 is not limited to the above-mentioned composition form, and may also include other optical structures. The arrangement order of the optical structures in the display panel 4 is not limited to the above-mentioned order. In addition, the present application does not limit the materials of the light-shielding adhesive layer, the optical adhesive layer, and the cover plate, and the structures of the lower polarizer and the upper polarizer.

[0056] The display device has a display area 500, and the figure shows the boundary of the display area 500 ( Figure 6 ), a preset sight line 501 ( Figure 6 The inclined dot-dash line intersecting with the vertical dotted line in the figure) extends toward the inside of the display device and forms an intersection with the first surface of the light guide plate 31, and the distance from the end of the adhesive layer 33 away from the light source 32 to the boundary of the display area 500 is greater than the distance from the above intersection to the boundary of the display area 500. It should be noted that the "display area 500" described in this application refers to the effective visible light-emitting area of ​​the module or the module incorporated into the whole machine, wherein the above "module" refers to the product composed of the display panel and the backlight module, and the above "whole machine" refers to the final product such as notebooks, televisions, monitors, tablet computers, etc.

[0057] Among them, the above-mentioned preset line of sight 501 refers to an imaginary straight line formed between the user's eyes and the boundary of the display area 500 when the user uses the display device. The imaginary straight line intersects with the light-emitting surface of the display panel. Since the user's line of sight is not always perpendicular to the light-emitting surface of the display panel when using the display device, the above-mentioned preset line of sight 501 can be a line of sight that is inclined relative to the light-emitting surface of the display panel.

[0058] Optionally, the angle between the preset sight line 501 and the light emitting surface of the display panel is less than or equal to 45°. For example, in one embodiment, the angle between the preset sight line 501 and the light emitting surface of the display panel is equal to 45°, and the difference between the distance from the end of the adhesive layer 33 away from the light source 32 to the boundary of the display area 500 and the distance from the above intersection to the boundary of the display area 500 is 0.2-0.3mm. The present application controls the distance within the above range, on the one hand to prevent the adhesive layer 33 from being too narrow and affecting the bonding stability between the flexible circuit board 31 and the light guide plate 21, and on the other hand to avoid the adhesive layer 33 from appearing in the user's line of sight as much as possible (when the adhesive layer 33 appears in the user's line of sight, light shines on the adhesive layer 33 to form a bright spot), thereby reducing the possibility of bright spots appearing in the user's line of sight, improving the picture quality of the display device, and improving the user's experience.

[0059] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A backlight module, characterized in that: include: A back plate, comprising a bottom wall and a side wall connected to the bottom wall, wherein a receiving space is formed between the bottom wall and the side wall; An optical film set, which is arranged in the accommodation space, and the optical film set includes a light guide plate, and the light guide plate has a first surface facing the bottom wall and a light incident surface facing the side wall; A light-emitting component, comprising a flexible circuit board fixed to the first surface and a light source connected to the flexible circuit board, wherein a light-emitting surface of the light source faces the light-incident surface; A sinking groove is formed at one end of the bottom wall close to the light emitting component, and the flexible circuit board is in contact with the bottom surface of the sinking groove.

2. The backlight module according to claim 1, characterized in that: The light emitting component further comprises: An adhesive layer is respectively bonded and fixed to the first surface and the flexible circuit board.

3. The backlight module according to claim 2, characterized in that: The adhesive layer includes a first adhesive layer and a second adhesive layer bonded to the first adhesive layer, the first adhesive layer is bonded to the first surface, and the second adhesive layer is bonded to the flexible circuit board; The first adhesive layer is made of a transparent material, and the second adhesive layer has a reflective surface facing the first adhesive layer, and the reflective surface is used to reflect the light entering the light guide plate.

4. The backlight module according to claim 3, characterized in that: A plurality of light sources are arranged on the flexible circuit board at intervals along the extension direction of the light incident surface, a plurality of first adhesive layers are arranged, and each of the first adhesive layers is located between adjacent light sources; The second adhesive layer is integrally arranged and connected to the first adhesive layers.

5. The backlight module according to any one of claims 2 to 4, characterized in that: The sum of the thicknesses of the flexible circuit board and the adhesive layer in a natural state is greater than the distance from the first surface to the bottom surface of the sink.

6. The backlight module according to claim 1, characterized in that: A reinforcing plate or a covering film is disposed on the surface of the flexible circuit board facing away from the light guide plate.

7. The backlight module according to claim 1, characterized in that: The area of ​​the flexible circuit board outside the metal wiring area is provided with a mesh structure.

8. The backlight module according to claim 1, characterized in that: The depth of the sink is 0.05-0.08 mm.

9. A display device, characterized in that: The invention comprises a display panel and the backlight module according to any one of claims 2 to 8.

10. The display device according to claim 9, characterized in that: The display device has a display area, a preset line of sight at the edge of the display area forms an intersection with the first surface of the light guide plate, and a distance from one end of the glue layer away from the light source to the edge of the display area is greater than a distance from the intersection to the edge of the display area.

11. The display device according to claim 10, characterized in that: The angle between the preset line of sight and the light emitting surface of the display panel is less than or equal to 45°.

12. The display device according to claim 11, characterized in that: The difference between the distance from the end of the adhesive layer away from the light source to the border of the display area and the distance from the intersection to the border of the display area is 0.2-0.3 mm.

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