Backlight module and display device

Abstract

The application provides a backlight module and a display device. The backlight module comprises a first back plate, a circuit board, a light emitting unit, a light guide plate, a glue layer and a support layer. The circuit board is located on one side of the first back plate along a first direction; the light emitting unit and the light guide plate are located on a side of the circuit board away from the first back plate, and the light emitting unit is located on a side edge of the light guide plate along a second direction; the glue layer is located between the circuit board and the light guide plate; and the support layer is located between the first back plate and the circuit board. By inserting the support layer between the first back plate and the circuit board, the overall height of the light emitting unit on the circuit board can be raised, so that the activity space of the light emitting unit in the first direction is reduced, thereby the height difference of the light emitting unit in the first direction caused by the circuit board wrinkle can be reduced, and the firefly defect can be alleviated.

Description

Technical Field

[0001] This application relates to the field of display technology, and more particularly to a backlight module and a display device. Background Technology

[0002] The backlight module undergoes high and low temperatures during performance testing. The light guide plate and the circuit board are fixed together with lamp adhesive. However, due to the different shrinkage and expansion rates of the light guide plate and the circuit board, the circuit board is prone to wrinkles, resulting in poor firefly performance. Summary of the Invention

[0003] The purpose of this application is to provide a backlight module and display device that aims to mitigate the risk of firefly defects caused by circuit board wrinkles.

[0004] On one hand, this application provides a backlight module, the backlight module comprising:

[0005] First back panel;

[0006] The circuit board is located on one side of the first back plate along the first direction;

[0007] The light-emitting unit and the light guide plate are located on the side of the circuit board away from the first back plate, and the light-emitting unit is located on the side of the light guide plate along the second direction, which is perpendicular to the first direction;

[0008] An adhesive layer is located between the circuit board and the light guide plate;

[0009] A support layer is located between the first backplate and the circuit board.

[0010] In some embodiments, the orthographic projection of the light-emitting unit on the first back plate lies within the orthographic projection of the support layer on the first back plate.

[0011] In some embodiments, the backlight module further includes:

[0012] The first reflective sheet includes a first body portion, a first extension portion and a first recessed portion. The first body portion is located between the light guide plate and the first back plate. The first extension portion is located between the circuit board and the first back plate. The first recessed portion connects the first body portion and the first extension portion.

[0013] Wherein, the distance between the surface of the first extension near the light guide plate and the light guide plate is greater than the distance between the surface of the first body near the light guide plate and the light guide plate; the support layer includes the first extension.

[0014] In some embodiments, the first backplate includes:

[0015] The second body portion is located on the side of the first body portion away from the light guide plate;

[0016] The second extension is located on the side of the first extension away from the circuit board;

[0017] The second recessed portion connects the second body portion and the second extension portion;

[0018] The distance between the surface of the second extension near the light guide plate and the light guide plate is greater than the distance between the surface of the second body near the light guide plate and the light guide plate.

[0019] In some embodiments, the distance between the surface of the second extension near the light guide plate and the surface of the second body near the light guide plate is equal to the distance between the surface of the first extension near the light guide plate and the surface of the first body near the light guide plate.

[0020] In some embodiments, the distance between the surface of the first extension near the light guide plate and the surface of the first body near the light guide plate is smaller than the dimension of the support layer along the first direction.

[0021] In some embodiments, the backlight module further includes:

[0022] The second backplate is located on the side of the light guide plate and the light-emitting unit away from the first backplate;

[0023] The third backplate connects the edges of the first backplate and the second backplate and is disposed along the first direction;

[0024] The light-emitting unit, the light guide plate, the circuit board, the adhesive layer, and the support layer are housed in the space enclosed by the first back plate, the second back plate, and the third back plate.

[0025] In some embodiments, the backlight module further includes:

[0026] The second reflector is located on the side of the second back plate closest to the first back plate;

[0027] The distance between the light-emitting unit and the second reflective sheet is less than a preset distance.

[0028] In some embodiments, the light-emitting units are spaced apart along a third direction on the side of the light guide plate, the third direction being perpendicular to the first direction and the second direction; the orthographic projection of the adhesive layer on the third back plate is located between the orthographic projections of two adjacent light-emitting units on the third back plate.

[0029] On the other hand, this application provides a backlight module and a display device, wherein the display device includes the backlight module in any of the above embodiments.

[0030] This application provides a backlight module and a display device. The backlight module includes a first backplate, a circuit board, a light-emitting unit, a light guide plate, an adhesive layer, and a support layer. The circuit board is located on one side of the first backplate along a first direction; the light-emitting unit and the light guide plate are located on the side of the circuit board away from the first backplate, and the light-emitting unit is located on the side of the light guide plate along a second direction; the adhesive layer is located between the circuit board and the light guide plate, and the support layer is located between the first backplate and the circuit board. By inserting a support layer between the first backplate and the circuit board, the overall height of the light-emitting unit on the circuit board can be increased, thereby reducing the movement space of the light-emitting unit in the first direction and reducing the height difference of the light-emitting unit in the first direction caused by circuit board wrinkles, thus mitigating firefly-like defects. Attached Figure Description

[0031] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0032] Figure 1 This is a schematic diagram of the structure of a backlight module provided in some embodiments of this application;

[0033] Figure 2 This is a schematic diagram of the arrangement structure of the adhesive layer and the light-emitting unit provided in some embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the structure of a backlight module provided in some embodiments of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0039] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a backlight module provided in some embodiments of this application. The backlight module 100 can be applied to various electronic devices, such as wearable devices like smart bracelets, smartwatches, augmented reality (AR) and virtual reality (VR) devices, mobile phones, e-books and e-newspapers, televisions, personal portable computers, foldable and rollable flexible display and lighting devices.

[0040] The backlight module 100 includes a first backplate 10, a circuit board 20, a light-emitting unit 30, a light guide plate 40, an adhesive layer 50, and a support layer 60. The circuit board 20 is located on one side of the first backplate 10 along a first direction (X); the light-emitting unit 30 and the light guide plate 40 are located on the side of the circuit board 20 away from the first backplate 10, and the light-emitting unit 30 is located on the side of the light guide plate 40 along a second direction (Y); the adhesive layer 50 is located between the circuit board 20 and the light guide plate 40, and the support layer 60 is located between the first backplate 10 and the circuit board 20.

[0041] The backlight module 100 may further include a second backplate 11 and a third backplate 12. The second backplate 11 is located on the side of the light guide plate 40 and the light-emitting unit 30 away from the first backplate 10. The third backplate 12 connects the edges of the first backplate 10 and the second backplate 11 and is disposed along the first direction (X). The first backplate 10, the second backplate 11, and the third backplate 12 can be a single unit. The light-emitting unit 30, the light guide plate 40, the circuit board 20, the adhesive layer 50, and the support layer 60 are accommodated within the space enclosed by the first backplate 10, the second backplate 11, and the third backplate 12.

[0042] The circuit board 20 may include a flexible printed circuit (PFC), and the light-emitting unit 30 is soldered on the side of the flexible printed circuit board 20 away from the first back plate 10. The flexible printed circuit board is used to control the light-emitting unit 30 to emit light.

[0043] The light-emitting unit 30 may include a light-emitting diode (LED) display or other suitable light source.

[0044] The light guide plate 40 can conduct the light emitted by the light-emitting unit 30 on its side. The adhesive layer 50 is used to fix the light guide plate 40 and the circuit board 20. Therefore, the adhesive layer 50 and the light-emitting unit 30 are both located on the circuit board 20.

[0045] Please see Figure 2 , Figure 2 This is a schematic diagram of the arrangement structure of the adhesive layer and the light-emitting unit provided in some embodiments of this application.

[0046] In some embodiments, the light-emitting units 30 are spaced apart along a third direction (Z) on the side of the light guide plate 40, and the adhesive layers 50 are spaced apart along a third direction (Z), which is perpendicular to the first direction (X) and the second direction (Y). The orthographic projection of the adhesive layer 50 on the third back plate 12 (XZ plane) is located between the orthographic projections of two adjacent light-emitting units 30 on the third back plate 12 (XZ plane). That is, both the adhesive layer 50 and the light-emitting units 30 are spaced apart along the third direction (Z), but the adhesive layer 50 is offset from the light-emitting units 30 by a certain distance along the third direction (Z), so that the adhesive layer 50 and the light-emitting units 30 are not aligned along the second direction (Y), thereby the adhesive layer 50 will not affect the light emitted by the light-emitting units 30.

[0047] The backlight module 100 may further include a light-shielding adhesive 70 and a backlight film 80. The light-shielding adhesive 70 is located on the side of the second back plate 11 away from the first back plate 10, and the backlight film 80 is located on the side of the light guide plate 40 away from the first back plate 10, and is disposed adjacent to the light-shielding adhesive 70 and the second back plate 11. The area where the backlight film 80 is located can be the light-emitting area of ​​the backlight module 100, and the backlight film 80 may include three or four optical film layers. The area where the light-shielding adhesive 70 is located can be the light-incident area of ​​the backlight module 100.

[0048] In some embodiments, the support layer 60 may include a rigid material such as polyethylene terephthalate (PET).

[0049] In some embodiments, the orthographic projection of the light-emitting unit 30 on the first back plate 10 lies within the orthographic projection of the support layer 60 on the first back plate 10.

[0050] In some embodiments, the backlight module 100 may further include a first reflective sheet 90, which is located between the light guide plate 40 and the first back plate 10, i.e., in the light-emitting area. Figure 1 As shown, the first reflective sheet 90 and the support layer 60 are separated and disposed on the first back plate 10. In some embodiments, the first back plate 10 may include a second body portion 101, a second extension portion 102, and a second recessed portion 103. The second body portion 101 is located on the side of the first reflective sheet 90 away from the light guide plate 40, the second extension portion 102 is located on the side of the support layer 60 away from the circuit board 20, and the second recessed portion 103 connects the second body portion 101 and the second extension portion 102. The distance between the surface of the second extension portion 102 near the light guide plate 40 and the light guide plate 40 is greater than the distance between the surface of the second body portion 101 near the light guide plate 40 and the light guide plate 40; that is, the second extension portion 102 is further away from the light guide plate 40 relative to the second body portion 101, to reserve space for the support layer 60.

[0051] In some embodiments, the distance between the surface of the second extension 102 near the light guide plate 40 and the surface of the second body 101 near the light guide plate 40 is less than the dimension of the support layer 60 along the first direction (X). That is, the dimension by which the second extension 102 sinks relative to the second body 101 along the first direction (X), i.e., the height difference between the second extension 102 (upper surface) and the second body 101 (upper surface), is less than the dimension (i.e., thickness) of the support layer 60 along the first direction (X). This ensures that the insertion of the support layer 60 elevates the circuit board 20 and the light-emitting unit 30.

[0052] The inventors discovered that during performance testing, the backlight module experiences both high and low temperature environments. During these tests, both the light guide plate 40 and the circuit board 20 contract and expand. However, due to the inconsistent rates of contraction and expansion between the two, wrinkles form on the circuit board 20 where the adhesive layer 50 is not applied. These wrinkles cause variations in the height of the light-emitting units 30 at different locations, resulting in poor glow quality.

[0053] In some embodiments, the backlight module 100 further includes a second reflective sheet 110, which is located on the side of the second back plate 11 closest to the first back plate 10. Specifically, the second reflective sheet 110 is located between the light-emitting unit 30 and the second back plate 11, and also between the light guide plate 40 and the second back plate 11. The second reflective sheet 110 can be bonded to the second back plate 11 using double-sided adhesive 120. The distance between the light-emitting unit 30 and the second reflective sheet 110 is less than a preset distance.

[0054] Since the support layer 60 can raise the overall height of the light-emitting unit 30, the distance between the light-emitting unit 30 and the second reflective sheet 110 can be less than a preset distance, or even the light-emitting unit 30 can directly contact the second reflective sheet 110. This can reduce the activity space of the light-emitting unit 30 in the first direction (X), and even if the circuit board 20 has wrinkles, the height difference of the light-emitting unit 30 caused by the wrinkles can be reduced, thereby improving the firefly effect.

[0055] The preset distance can be less than the height difference caused by the wrinkles on the circuit board 20. Therefore, the preset distance can be determined according to the experiment or actual situation.

[0056] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a backlight module provided in some embodiments of this application. For ease of understanding and brief explanation, the same structures as those in the above embodiments will continue to use the same reference numerals, and the same structures will not be described in detail. This embodiment will only describe the different structures in detail.

[0057] Backlight module 200 and Figure 1The difference in the embodiment is that the first reflective sheet 90a includes a first body portion 91, a first extension portion 92, and a first recessed portion 93. The first body portion 91 is located between the light guide plate 40 and the first back plate 10, the first extension portion 92 is located between the circuit board 20 and the first back plate 10, and the first recessed portion 93 connects the first body portion 91 and the first extension portion 92. The distance between the surface of the first extension portion 92 near the light guide plate 40 and the light guide plate 40 is greater than the distance between the surface of the first body portion 91 near the light guide plate 40 and the light guide plate 40. The support layer 60 includes the first extension portion 92; in one embodiment, the first extension portion 92 can directly serve as the support layer 60.

[0058] Since the circuit board 20 is also transparent, by extending the first reflective sheet 90a from the light-emitting area to the light-receiving area, the first extension 92 is disposed between the circuit board 20 and the first back plate 10, which can prevent light from passing through the circuit board 20, improve the reflectivity of light, and increase the backlight brightness by 3-5%.

[0059] In some embodiments, the distance between the surface of the first extension 92 near the light guide plate 40 and the surface of the first body portion 91 near the light guide plate 40 is less than the dimension of the support layer 60 along the first direction (X). In other words, the dimension by which the first extension 92 sinks relative to the first body portion 91 along the first direction (X), i.e., the height difference between the first extension 92 (upper surface) and the first body portion 91 (upper surface), is less than the dimension (i.e., thickness) of the support layer 60 along the first direction (X). This ensures that the insertion of the support layer 60 can raise the circuit board 20 and the light-emitting unit 30.

[0060] In some embodiments, the distance between the surface of the second extension 102 near the light guide plate 40 and the surface of the second body 101 near the light guide plate 40 is equal to the distance between the surface of the first extension 92 near the light guide plate 40 and the surface of the first body 91 near the light guide plate 40. This can be understood as the dimension by which the second extension 102 sinks relative to the second body 101 along the first direction (X) being equal to the dimension by which the first extension 92 sinks relative to the first body 91 along the first direction (X). In other words, the height difference between the second extension 102 and the second body 101 can be equal to the height difference between the first extension 92 and the first body 91.

[0061] The backlight module provided in this embodiment includes a first backplate 10, a circuit board 20, a light-emitting unit 30, a light guide plate 40, an adhesive layer 50, and a support layer 60. The circuit board 20 is located on one side of the first backplate 10 along a first direction (X); the light-emitting unit 30 and the light guide plate 40 are located on the side of the circuit board 20 away from the first backplate 10, and the light-emitting unit 30 is located on the side of the light guide plate 40 along a second direction (Y); the adhesive layer 50 is located between the circuit board 20 and the light guide plate 40, and the support layer 60 is located between the first backplate 10 and the circuit board 20. By inserting the support layer 60 between the first backplate 10 and the circuit board 20, the overall height of the light-emitting unit 30 on the circuit board 20 can be increased, reducing the activity space of the light-emitting unit 30 in the first direction (X), thereby reducing the height difference of the light-emitting unit 30 in the first direction (X) caused by wrinkles in the circuit board 20, and mitigating firefly-related issues.

[0062] On the other hand, embodiments of this application also provide a display device, which includes the backlight module provided in any of the above embodiments. This display device has the same beneficial effects as the backlight module described above, and will not be repeated here.

[0063] The above description of the embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application; those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A backlight module, characterized in that, The backlight module includes: First back panel; The circuit board is located on one side of the first back plate along the first direction; The light-emitting unit and the light guide plate are located on the side of the circuit board away from the first back plate, and the light-emitting unit is located on the side of the light guide plate along the second direction, which is perpendicular to the first direction; An adhesive layer is located between the circuit board and the light guide plate; A support layer is located between the first backplate and the circuit board; The first reflective sheet includes a first body portion and a first extension portion. The first body portion is located between the light guide plate and the first back plate, and the first extension portion is located between the circuit board and the first back plate. The first extension portion serves as the support layer. The distance between the surface of the first extension portion near the light guide plate and the light guide plate is greater than the distance between the surface of the first body portion near the light guide plate and the light guide plate. The distance between the surface of the first extension portion near the light guide plate and the surface of the first body portion near the light guide plate is less than the dimension of the support layer along the first direction.

2. The backlight module according to claim 1, characterized in that, The orthographic projection of the light-emitting unit on the first back plate lies within the orthographic projection of the support layer on the first back plate.

3. The backlight module according to claim 1, characterized in that, The first reflective sheet further includes a first recessed portion, which connects the first body portion and the first extension portion.

4. The backlight module according to claim 3, characterized in that, The first backplate includes: The second body portion is located on the side of the first body portion away from the light guide plate; The second extension is located on the side of the first extension away from the circuit board; The second recessed portion connects the second body portion and the second extension portion; The distance between the surface of the second extension near the light guide plate and the light guide plate is greater than the distance between the surface of the second body near the light guide plate and the light guide plate.

5. The backlight module according to claim 4, characterized in that, The distance between the surface of the second extension near the light guide plate and the surface of the second body near the light guide plate is equal to the distance between the surface of the first extension near the light guide plate and the surface of the first body near the light guide plate.

6. The backlight module according to claim 1, characterized in that, The backlight module also includes: The second backplate is located on the side of the light guide plate and the light-emitting unit away from the first backplate; The third backplate connects the edges of the first backplate and the second backplate and is disposed along the first direction; The light-emitting unit, the light guide plate, the circuit board, the adhesive layer, and the support layer are housed in the space enclosed by the first back plate, the second back plate, and the third back plate.

7. The backlight module according to claim 6, characterized in that, The backlight module also includes: The second reflector is located on the side of the second back plate closest to the first back plate; The distance between the light-emitting unit and the second reflective sheet is less than a preset distance.

8. The backlight module according to claim 6, characterized in that, The light-emitting units are arranged at intervals along a third direction on the side of the light guide plate, and the third direction is perpendicular to the first direction and the second direction; the orthographic projection of the adhesive layer on the third back plate is located between the orthographic projections of two adjacent light-emitting units on the third back plate.

9. A display device, characterized in that, The display device includes the backlight module as described in any one of claims 1-8.

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