Backlight module and display device

Abstract

Embodiments of the present application provide a backlight module and a display device, and relate to the technical field of display. The purpose is to at least alleviate the problem that the effective bonding area of lamp adhesive is small and easy to debond in the related art. The backlight module comprises a back plate, a light source assembly, a light guide plate and a lamp adhesive. The light source assembly is arranged on the back plate, and the light source assembly comprises a flexible circuit board and a sub light source electrically connected with the flexible circuit board. At least one first groove is formed on the side of the flexible circuit board close to the light guide plate. The light guide plate is arranged on the back plate and located on the light emitting side of the sub light source. The lamp adhesive is at least partially filled in the first groove and bonds the flexible circuit board and the light guide plate.

Description

Technical Field

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

[0002] Backlight modules typically include components such as light source components and light guide plates. The light source components often adopt a structure in which a flexible circuit board carries a sub-light source (such as an LED bead). The light emitted by the sub-light source is conducted and diffused by the light guide plate to provide uniform backlight for the display panel.

[0003] To ensure the relative positional accuracy of the light guide plate and the light source assembly, related technologies typically use adhesive to bond the flexible circuit board to the light guide plate. However, since both the flexible circuit board and the light guide plate have planar bonding surfaces, the adhesive can only fill the gap between them, resulting in a relatively small effective bonding area. During the use of the display device, factors such as thermal expansion and contraction of materials due to changes in ambient temperature and vibration can easily cause the adhesive to experience a decrease in bonding strength and delamination. This can lead to gaps between the light guide plate and the light source assembly, causing display defects such as light leakage and uneven brightness. Utility Model Content

[0004] This application provides a backlight module and display device to at least alleviate the problems in the related art, such as the small effective bonding area of ​​the lamp adhesive leading to easy detachment.

[0005] On one hand, embodiments of this application provide a backlight module, including: Back panel; A light source assembly is disposed on the back plate, the light source assembly including a flexible circuit board and a sub-light source electrically connected to the flexible circuit board; A light guide plate is disposed on the back plate and located on the light-emitting side of the sub-light source; and Lamp glue; The flexible circuit board has at least one first groove on the side near the light guide plate, and the lamp adhesive at least partially fills the first groove and bonds the flexible circuit board and the light guide plate.

[0006] In some embodiments, the first groove is provided in multiple rows, and the multiple first grooves in the same row are spaced apart along the first direction, and the first grooves in adjacent rows are staggered.

[0007] In some embodiments, the lamp adhesive includes a first portion located within the first groove and a second portion located outside the first groove, the first portion and the second portion being connected to each other.

[0008] In some embodiments, the light guide plate has at least one second groove on the side near the flexible circuit board, and the lamp adhesive is partially filled in the second groove.

[0009] In some embodiments, the second groove is provided in multiple ways, and the orthographic projection of each second groove on the flexible circuit board is offset from the orthographic projection of the first groove on the flexible circuit board.

[0010] In some embodiments, the lamp adhesive includes a substrate layer and a buffer layer located on the side of the substrate layer near the light guide plate, the buffer layer being used to absorb the deformation stress of the light guide plate in the horizontal direction.

[0011] In some embodiments, the buffer layer is a polydimethylsiloxane buffer layer.

[0012] In some embodiments, the lamp adhesive contains scattering particles.

[0013] In some embodiments, the scattering particles include nano-silica particles.

[0014] On the other hand, embodiments of this application also provide a display device, which includes a backlight module as described in any of the above embodiments.

[0015] For the backlight module provided in this application embodiment, the flexible circuit board has a relatively small Young's modulus, which is beneficial for the creation of the first groove. Since the first groove is formed on the flexible circuit board, and the lamp adhesive is at least partially filled within it, the bonding area between the lamp adhesive and the flexible circuit board is effectively increased, thereby improving the bonding stability between the flexible circuit board and the light guide plate. Furthermore, the lamp adhesive partially filling the first groove can form a structure similar to a "mechanical interlock," which can more effectively resist the influence of environmental factors. For example, during temperature changes, the materials of the lamp adhesive and the flexible circuit board will generate certain stresses during thermal expansion and contraction. Since the lamp adhesive is located in the first groove, these stresses can be dispersed, reducing the risk of lamp adhesive detachment due to stress concentration. In addition, when the backlight module is subjected to slight vibration, this structure can effectively suppress the relative displacement between the flexible circuit board and the light guide plate, preventing loosening of the bond due to vibration, thereby ensuring the stable operation of the backlight module. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is a cross-sectional structural diagram of a backlight module provided in some embodiments of this application; Figure 2 This is a schematic diagram showing the positional relationship between the flexible circuit board and the lamp adhesive according to some embodiments of this application; Figure 3 This is a cross-sectional view of a backlight module provided in some other embodiments of this application; Figure 4 This is a schematic diagram showing the positional relationship between the flexible circuit board and the light guide plate according to some embodiments of this application; Figure 5 This is a cross-sectional structural diagram of a display device provided in some embodiments of this application. Detailed Implementation

[0018] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. The described technical solutions are for illustrative purposes only and should not be construed as limiting the scope of protection of this application.

[0019] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are only used to distinguish different technical features. The term "multiple" and similar words indicate two or more unless otherwise expressly defined.

[0020] The various embodiments of this application are similar, and features from different embodiments and / or different examples can be combined with each other.

[0021] Some embodiments of this application provide a backlight module, such as Figure 1 As shown, the backlight module 100 includes: a backplate 10, a light source assembly 20, a light guide plate 30, and lamp adhesive 40.

[0022] A light source assembly 20 is disposed on a back plate 10. The back plate 10 provides stable support for the light source assembly 20 to ensure the stability of its light emission. The light source assembly 20 includes a flexible circuit board 21 and a sub-light source 22 electrically connected to the flexible circuit board 21. The sub-light source 22 may be, for example, a light-emitting diode (LED). The flexible circuit board 21 has at least one first groove K1 on the side near the light guide plate 30. The light guide plate 30 is disposed on the back plate 10 and located on the light-emitting side of the sub-light source 22. The light emitted by the sub-light source 22, after being conducted and diffused by the light guide plate 30, can provide uniform backlighting for the display panel.

[0023] The lamp adhesive 40 is at least partially filled in the first groove K1 and bonded to the flexible circuit board 21 and the light guide plate 30.

[0024] In this embodiment, the flexible circuit board 21 has a relatively small Young's modulus, which is beneficial for the creation of the first groove K1. Since the first groove K1 is formed on the flexible circuit board 21, and the lamp adhesive 40 is at least partially filled within the first groove K1, the bonding area between the lamp adhesive 40 and the flexible circuit board 21 is effectively increased, thereby improving the bonding stability between the flexible circuit board 21 and the light guide plate 30. Furthermore, the partial filling of the lamp adhesive 40 within the first groove K1 can form a structure similar to a "mechanical interlock," which can more effectively resist the influence of environmental factors. For example, during temperature changes, the materials of the lamp adhesive 40 and the flexible circuit board 21 will generate certain stresses during thermal expansion and contraction. Since the lamp adhesive 40 is partially located in the first groove K1, these stresses can be dispersed, reducing the risk of the lamp adhesive 40 detaching due to stress concentration. In addition, when the backlight module is subjected to slight vibration, this structure can effectively suppress the relative displacement between the flexible circuit board 21 and the light guide plate 30, preventing loosening of the bond due to vibration, thereby ensuring the stable operation of the backlight module 100.

[0025] In some examples, multiple first grooves K1 are provided and arranged at intervals to each other, which can reduce the adverse effects of opening the first grooves K1 on the structural stability of the flexible circuit board 21.

[0026] In some examples, the depth of the first groove K1 can be less than or equal to 50 μm. This can effectively increase the bonding area between the adhesive 40 and the flexible circuit board 21. In addition, the cross-sectional shape of the first groove K1 in the thickness direction of the flexible circuit board 21 can be triangular, rectangular, semi-elliptical, etc., and this application embodiment does not limit this.

[0027] It is worth noting that the depth of the first groove K1 is related to the thickness of the flexible circuit board 21. When the depth of the first groove K1 is 50 μm, the thickness of the flexible circuit board 21 is greater than 50 μm. The flexible circuit board 21 includes a substrate made of flexible material and metal traces located on the substrate. The location of the first groove K1 needs to avoid the location of the metal traces to ensure the functional stability of the flexible circuit board 21.

[0028] In some embodiments, such as Figure 2 As shown, multiple first grooves K1 are arranged in multiple rows. Multiple first grooves K1 located in the same row are spaced apart along the first direction X, and the first grooves K1 in adjacent rows are staggered.

[0029] When the flexible circuit board 21 is subjected to stress by the external environment, the first grooves K1 located in the same row are distributed at intervals along the first direction X, which can effectively disperse the stress in that direction. Meanwhile, the staggered arrangement of the first grooves K1 in another row fills the stress gaps formed by the intervals between the first grooves K1 in the previous row, thus making the stress distribution on the entire bonding surface more uniform. Therefore, both thermal stress caused by temperature changes and shear stress caused by vibration can be more dispersed and transferred to the adhesive 40 and the flexible circuit board 21, preventing excessive local stress from causing the adhesive 40 to crack or detach, thereby improving the bonding stability between the adhesive 40 and the flexible circuit board 21.

[0030] As an example, multiple rows of first grooves K1 are arranged along a second direction Y, which is perpendicular to the first direction X. The orthographic projections of two adjacent rows of first grooves K1 onto a reference plane do not overlap, and this reference plane is perpendicular to the second direction Y. For example, in two adjacent rows of first grooves K1, the orthographic projection of each first groove K1 in the first row onto the reference plane lies between the orthographic projections of two adjacent first grooves K1 in the second row onto the reference plane and they do not overlap.

[0031] In some examples, the spacing between two adjacent first grooves K1 in the first direction X can be set to 200 μm. The backlight module provided in this application embodiment utilizes a "mechanical interlock" structure to increase the peel strength between the flexible circuit board 21 and the lamp adhesive 40 from 1.2 N / mm to 2.5 N / mm using structures in related technologies, and reduces the wrinkle rate of the flexible circuit board 21 by 90%.

[0032] Furthermore, the inventors conducted a thermal shock test (TST) on the backlight module 100 provided in the embodiments of this application and backlight modules in related technologies. The backlight module 100 provided in the embodiments of this application can increase the TST pass rate from 70% achieved by backlight modules in related technologies to over 98%. Therefore, the backlight module 100 provided in the embodiments of this application has relatively better yield and stability in use.

[0033] In some embodiments, please continue reading Figure 2 The lamp adhesive 40 includes a first part 41 located inside the first groove K1 and a second part 42 located outside the first groove K1, and the first part 41 and the second part 42 are connected to each other.

[0034] In this configuration, the lamp adhesive 40 is arranged continuously. This increases the bonding area between the flexible circuit board 21 and the light guide plate 30, thereby improving the bonding stability between them. Furthermore, it optimizes the stress distribution of the lamp adhesive 40, enhancing its structural stability. In addition, the continuous arrangement of the lamp adhesive 40 also improves the sealing between the flexible circuit board 21 and the light guide plate 30, thus enhancing the light emission effect of the backlight module 100.

[0035] As an example, the shape of the orthographic projection of the lamp adhesive 40 onto the flexible circuit board 21 is a closed shape, such as a rectangle, a rounded rectangle, etc.

[0036] In some embodiments, such as Figure 3 As shown, the light guide plate 30 has at least one second groove K2 on the side near the flexible circuit board 21, and the lamp adhesive 40 is partially filled in the second groove K2.

[0037] In this embodiment, since the light guide plate 30 has a second groove K2, and the lamp adhesive 40 is partially filled in the second groove K2, the bonding area between the lamp adhesive 40 and the light guide plate 30 is effectively increased, thereby improving the bonding stability between the flexible circuit board 21 and the light guide plate 30. Furthermore, the partial filling of the lamp adhesive 40 in the second groove K2 can form a structure similar to a "mechanical interlock," which can more effectively resist the influence of environmental factors. For example, when the temperature changes, the material of the lamp adhesive 40 will generate certain stress during thermal expansion and contraction. Since the lamp adhesive 40 is partially located in the second groove K2, this stress can be dispersed, reducing the risk of the lamp adhesive 40 detaching due to stress concentration. In addition, when the backlight module is subjected to slight vibration, this structure can effectively suppress the relative displacement between the flexible circuit board 21 and the light guide plate 30, avoiding loosening of the bond due to vibration, thereby ensuring the stable operation of the backlight module 100.

[0038] In some examples, there is no gap between the lamp adhesive 40 and the sidewall of the second groove K2. This helps to improve the interface between the lamp adhesive 40 and the light guide plate 30 and reduce optical loss.

[0039] In some embodiments, such as Figure 4 As shown, there are multiple second grooves K2, and the orthographic projection of each second groove K2 on the flexible circuit board 21 is offset from the orthographic projection of the first groove K1 on the flexible circuit board 21.

[0040] This design allows stresses generated by changes in the external environment (such as temperature changes) to be dispersed along staggered paths on the flexible circuit board 21 and the light guide plate 30, forming a three-dimensional stress dispersion network. When stress is transmitted through the adhesive 40, it diffuses along the dispersion paths of the first groove K1 on the flexible circuit board 21 and the second groove K2 on the light guide plate 30, respectively, with no overlap between the two paths. This effectively avoids the problem of stress concentration areas overlapping, which could lead to cracking of the adhesive 40 or localized damage to the flexible circuit board 21 and the light guide plate 30. Furthermore, the filling portions of the adhesive 40 within the first groove K1 and the second groove K2 form an interlaced structure resembling "support pillars." These "support pillar" structures are staggered, forming a more stable support system between the flexible circuit board 21 and the light guide plate 30. When the backlight module 100 is subjected to external impact or deformation, the interlaced "support pillar" structure can share the external force from different directions, preventing excessive force in one direction from causing deformation or breakage of the adhesive 40.

[0041] In some embodiments, please continue reading Figure 1 and Figure 3 The lamp adhesive 40 includes a substrate layer 401 and a buffer layer 402 located on the side of the substrate layer 401 near the light guide plate 30. The buffer layer 402 is used to absorb the deformation stress of the light guide plate 30 in the horizontal direction.

[0042] It is worth noting that, under the influence of factors such as temperature changes, the light guide plate 30 is prone to stretching or shifting in the horizontal direction (i.e., the direction perpendicular to the thickness direction of the light guide plate 30), thereby generating deformation stress. If these stresses are directly transmitted to the flexible circuit board 21 through the adhesive 40, it may cause deformation of the flexible circuit board 21. However, the buffer layer 402 can directly absorb the horizontal stress transmitted by the light guide plate 30 through its own deformation capacity, thereby reducing the stress transmission to the flexible circuit board 21 and effectively mitigating the impact of the deformation stress of the light guide plate 30 on the flexible circuit board 21.

[0043] In some examples, buffer layer 402 is a polydimethylsiloxane buffer layer. That is, buffer layer 402 comprises polydimethylsiloxane. The Shore hardness of buffer layer 402 can be controlled at A30, and its coefficient of thermal expansion can be controlled at 8.5 × 10⁻⁶. -6 / ℃.

[0044] In this case, the coefficient of thermal expansion of the buffer layer 402 is 8.5 × 10⁻⁶. -6 / ℃ and the coefficient of thermal expansion of the light guide plate 30 is 7.9×10. -6 With temperatures close to each other (°C), the deformation trends of both components during temperature fluctuations are relatively synchronized, effectively avoiding additional stress conflicts caused by differences in properties. Simultaneously, the elastic properties of the buffer layer 402, with a Shore hardness of A30, allow for moderate deformation. This allows it to expand and contract in response to the horizontal deformation of the light guide plate 30, while also absorbing the stress generated by deformation through its own elastic restoring force, thus achieving dynamic stress adjustment. Therefore, the backlight module 100 in this embodiment can maintain a stable structural state and optical performance, effectively improving product reliability and lifespan.

[0045] In some embodiments, the lamp adhesive 40 contains scattering particles.

[0046] By incorporating scattering particles, the refractive index matching between the lamp adhesive 40 and the light guide plate 30 can be improved, reducing light loss at their interface and enhancing the light extraction efficiency of the backlight module 100. In related technologies, when double-sided adhesive is used to bond the lamp adhesive to the light guide plate, the interface loss between the two is significant, resulting in a light efficiency loss rate greater than 8%. However, in this embodiment, by incorporating scattering particles in the substrate layer 401, a refractive index gradient matching can be achieved, thereby reducing the light efficiency loss rate to below 3%.

[0047] In some examples, the scattering particles may be disposed within the substrate layer 401 of the lamp adhesive 40.

[0048] As an example, scattering particles include nano-silica particles.

[0049] By incorporating nano-sized silica particles, with particle sizes at the nanometer level—on the same order of magnitude as the wavelength of visible light—particles of this size exhibit strong scattering ability for visible light, according to Mie scattering theory. These nano-sized silica particles can more efficiently scatter light of different wavelengths, resulting in more uniform dispersion of the light emitted by the sub-light source within the lamp adhesive 40, thereby improving the light emission performance of the backlight module 100. Furthermore, silica particles possess high hardness and chemical stability; incorporating them into the lamp adhesive 40 effectively enhances its overall mechanical strength and aging resistance.

[0050] In some embodiments, the lamp adhesive 40 may include a silicone rubber material and a liquid curing agent.

[0051] For lamp adhesives using double-sided tape in related technologies, the elastic modulus fluctuation is typically greater than 50% in the temperature range of -40℃ to 85℃. For the lamp adhesive 40 in this embodiment, the elastic modulus fluctuation is less than 10% in the same temperature range, therefore its elastic modulus fluctuation is significantly better than that of double-sided tapes in related technologies.

[0052] In some examples, the lamp adhesive 40 can be applied between the flexible circuit board 21 and the light guide plate 30, filling the first groove K1; then it is cured with ultraviolet light, simultaneously completing the molding of the lamp adhesive 40 and the bonding of the flexible circuit board 21 and the light guide plate 30. This can effectively improve the activation rate of the lamp adhesive. Compared with the step-by-step bonding method using double-sided adhesive in related technologies, the above method can eliminate the cutting and positioning steps, thereby shortening the production cycle by 30%, effectively reducing material waste, and thus reducing process costs.

[0053] As an example, in all components of lamp adhesive 40, the liquid hardener can be set to a proportion of 5%, while the nano silica particles can be set to a proportion of 8%.

[0054] Some embodiments of this application also provide a display device, such as... Figure 5 As shown, the display device 1000 includes the backlight module 100 described in any of the above embodiments and the display panel 200 located on the light-emitting side of the backlight module 100.

[0055] Since it includes a backlight module 100, the display device 1000 has the technical effects of the backlight module 100 described above, which will not be repeated here.

[0056] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A backlight module, characterized in that, include: Back panel; A light source assembly is disposed on the back plate, the light source assembly including a flexible circuit board and a sub-light source electrically connected to the flexible circuit board; A light guide plate is disposed on the back plate and located on the light-emitting side of the sub-light source; and Lamp glue; The flexible circuit board has at least one first groove on the side near the light guide plate, and the lamp adhesive at least partially fills the first groove and bonds the flexible circuit board and the light guide plate.

2. The backlight module according to claim 1, characterized in that, The first groove is provided in multiple rows, and the multiple first grooves in the same row are spaced apart along the first direction, and the first grooves in adjacent rows are staggered.

3. The backlight module according to claim 1, characterized in that, The lamp adhesive includes a first portion located inside the first groove and a second portion located outside the first groove, the first portion and the second portion being connected to each other.

4. The backlight module according to any one of claims 1-3, characterized in that, The light guide plate has at least one second groove on the side near the flexible circuit board, and the lamp adhesive is partially filled in the second groove.

5. The backlight module according to claim 4, characterized in that, The second groove is provided in multiple ways, and the orthographic projection of each second groove on the flexible circuit board is offset from the orthographic projection of the first groove on the flexible circuit board.

6. The backlight module according to any one of claims 1-3, characterized in that, The lamp adhesive includes a substrate layer and a buffer layer located on the side of the substrate layer near the light guide plate. The buffer layer is used to absorb the deformation stress of the light guide plate in the horizontal direction.

7. The backlight module according to claim 6, characterized in that, The buffer layer is a polydimethylsiloxane buffer layer.

8. The backlight module according to any one of claims 1-3, characterized in that, The lamp adhesive contains scattering particles.

9. The backlight module according to claim 8, characterized in that, The scattering particles include nano-silica particles.

10. A display device, characterized in that, include: The backlight module as described in any one of claims 1-9.

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