Composite backboard and display device

Abstract

The invention relates to a composite backboard and a display device, and relates to the technical field of display. The composite backboard comprises a first heat conduction layer, a backboard layer, a second heat conduction layer and a plurality of third heat conduction layers, wherein the heat conductivity coefficient of a material used by the first heat conduction layer, the heat conductivity coefficient of a material used by the second heat conduction layer and the heat conductivity coefficient of a material used by the third heat conduction layer are all greater than the heat conductivity coefficient of a material used by the back plate layer; the backboard layer is provided with a plurality of through holes corresponding to the third heat conduction layers in a one-to-one mode, and the third heat conduction layers are located in the corresponding through holes and connected with the first heat conduction layer and the second heat conduction layer. According to the composite backboard, the supporting performance of the display device is guaranteed, the heat dissipation efficiency is improved, and therefore the display performance of the display device is improved, and the service life of the display device is prolonged.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and more particularly, to a composite backplane and a display device. Background Art

[0002] In existing OLED mobile terminal products, a stainless steel backplane is used to support the strength of the OLED display screen. However, the stainless steel has a low thermal conductivity coefficient and cannot play a good role in heat conduction, which will reduce the heat conduction inside the whole machine and the heat dissipation performance and service life of the OLED screen.

[0003] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] The purpose of the present disclosure is to overcome the above-mentioned deficiencies of the prior art, and to provide a composite backplane and a display device, which can reduce the adverse effects of high temperature on the display device during use by improving the heat dissipation efficiency of the composite backplane.

[0005] According to one aspect of the present disclosure, a composite backplane is provided, which is located on the back side of a display panel. The composite backplane includes a first heat conduction layer, a backplane layer, and a second heat conduction layer that are sequentially stacked, and further includes a plurality of third heat conduction layers; wherein, the thermal conductivity coefficients of the materials used for the first heat conduction layer, the second heat conduction layer, and the third heat conduction layer are all greater than the thermal conductivity coefficient of the material used for the backplane layer;

[0006] The backplane layer has a plurality of through holes corresponding one by one to the plurality of third heat conduction layers, and the third heat conduction layer is located in the corresponding through hole and is connected to the first heat conduction layer and the second heat conduction layer.

[0007] In an exemplary embodiment of the present disclosure, the third heat conduction layer is made of the same material as the first heat conduction layer and is integrally formed.

[0008] In an exemplary embodiment of the present disclosure, the third heat conduction layer fills the corresponding through hole and is fixed to the backplane layer; the material of the third heat conduction layer is different from the materials of the first heat conduction layer and the second heat conduction layer.

[0009] In an exemplary embodiment of the present disclosure, the first heat conduction layer includes a substrate portion and connection portions corresponding one by one to the plurality of third heat conduction layers, and the connection portions are made of the same material as the corresponding third heat conduction layers and are integrally formed;

[0010] The substrate portion has connection holes corresponding one by one to the respective connection portions, and the connection portions are received in the corresponding connection holes and are connected to the substrate portion.

[0011] In an exemplary embodiment of the present disclosure, the third heat-conducting layer is disposed around the sidewall of the corresponding through hole, and the third heat-conducting layer forms a first cavity;

[0012] The first heat-conducting layer has second cavities that correspond to and are connected to the first cavities one by one;

[0013] The first heat-conducting layer and the third heat-conducting layer are made of the same material and integrally formed.

[0014] In an exemplary embodiment of the present disclosure, the composite backplane further includes a heat-conducting connector that fills the first cavity and the second cavity, and the heat-conducting coefficient of the material used for the heat-conducting connector is greater than that of the backplane layer.

[0015] In an exemplary embodiment of the present disclosure, the elastic modulus of the backplane layer is greater than the elastic modulus of the first heat-conducting layer, and the elastic modulus of the backplane layer is greater than the elastic modulus of the third heat-conducting layer.

[0016] In an exemplary embodiment of the present disclosure, the total area of the orthographic projections of the respective through holes on the display panel on the backplane layer is 30% to 40% of the area of the orthographic projection of the backplane layer on the display panel.

[0017] In an exemplary embodiment of the present disclosure, the backplane layer includes a plurality of sub-regions, and the through-hole distribution density of at least one of the sub-regions is different from that of the other sub-regions;

[0018] Alternatively, the through-hole size of at least one of the sub-regions is different from that of the other sub-regions.

[0019] According to another aspect of the present disclosure, a display device is provided, including a display panel and the above-mentioned composite backplane.

[0020] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. Description of the Drawings

[0021] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic cross-sectional structure diagram of a display device in the related art.

[0023] Figure 2In an embodiment of the present disclosure, it is a schematic diagram of a partial cross-section of a composite backplane.

[0024] Figure 3 In an embodiment of the present disclosure, it is a schematic diagram of a partial cross-section of a composite backplane.

[0025] Figure 4 In an embodiment of the present disclosure, it is a schematic diagram of a partial cross-section of a composite backplane.

[0026] Figure 5 In an embodiment of the present disclosure, it is a schematic diagram of a partial cross-section of a composite backplane.

[0027] Figure 6 In an embodiment of the present disclosure, it is a schematic diagram of a partial cross-section of a composite backplane.

[0028] Figure 7 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the backplane layer.

[0029] Figure 8 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the backplane layer.

[0030] Figure 9 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the backplane layer.

[0031] Figure 10 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the backplane layer.

[0032] Figure 11 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the sub-region of the backplane layer.

[0033] Figure 12 In an embodiment of the present disclosure, it is a schematic diagram of the through-hole setting of the sub-region of the backplane layer.

[0034] Figure 13 In an embodiment of the present disclosure, it is a schematic diagram of the sectional structure of a display device.

[0035] The reference numerals are as follows:

[0036] AC1, the first cavity; AC2, the second cavity; CG, the cover plate; CNT, the thermal connection body; FPC, the flexible printed circuit board; OCA, the optical adhesive; PNL, the display panel; RPL, the backplane layer; RPL1, the first sub-region; RPL2, the second sub-region; SDIC, the driving chip; TC, the thermal conductive layer; TC1, the first thermal conductive layer; TC11, the substrate part; TC12, the connecting part; TC2, the second thermal conductive layer; TC3, the third thermal conductive layer; TH, the through-hole; CRB, the composite backplane. Specific embodiments

[0037] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote like or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0038] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another component, these terms are used in this specification only for convenience, for example, according to the directions of the examples described in the accompanying drawings. It can be understood that if the device of the icon is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" another structure, it may mean that a structure is integrally formed on another structure, or that a structure is "directly" disposed on another structure, or that a structure is "indirectly" disposed on another structure through another structure.

[0039] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.; the terms "first", "second", "third", etc. are used only as labels and are not a limitation on the quantity of their objects.

[0040] In the related art, as Figure 1 shown, the display device includes a display panel PNL and a backplane assembly; a cover plate CG is disposed on a side of the display panel PNL away from the backplane assembly, and the cover plate CG can be connected to the display panel PNL through an optical adhesive OCA. The backplane assembly includes a backplane layer RPL and a heat conduction layer TC located on a side of the backplane layer RPL away from the display panel PNL; the backplane layer RPL is used to support the display device, and the backplane layer RPL can be made of stainless steel material. The heat conduction layer TC is used to conduct heat, and the heat conduction layer TC is a material with a relatively high heat conduction coefficient. That is to say, the heat transfer during the use of the display device is: the heat generated by the display panel PNL is conducted to the backplane layer RPL, and the backplane layer RPL further transfers the heat to the heat conduction layer TC for heat dissipation. However, the backplane layer RPL made of stainless steel has poor thermal conductivity and is difficult to quickly conduct heat to the heat conduction layer TC, so that the heat of the display panel PNL cannot be conducted out in time, resulting in a relatively high temperature of the display panel PNL, which affects the display performance and service life of the display panel PNL.

[0041] To solve the above problems, an embodiment of the present disclosure provides a display device. Refer to Figure 13 The display device includes a display panel PNL and a composite backplane CRB located on the back surface (non-light-emitting surface) of the display panel PNL. Compared with the stainless-steel backplane in the prior art, the composite backplane CRB can have a high heat transfer rate while having a high support capacity, and can take into account both the support and heat dissipation of the display panel PNL.

[0042] In one example, refer to Figure 13 The display device further includes a transparent cover plate CG on the light-emitting side of the display panel PNL, and the cover plate CG is fixed to the surface of the display panel PNL by an optical adhesive OCA.

[0043] Exemplarily, the cover plate CG can be a transparent glass cover plate.

[0044] In one example, the display device further includes a circuit board. The circuit board includes a flexible printed circuit board FPC; the display panel PNL includes a display area and a non-display area provided on at least one side of the display area. As Figure 13 shown, a driving chip SDIC is provided on the non-display area, and the driving chip SDIC is electrically connected to the flexible printed circuit board FPC.

[0045] Refer to Figures 2 - 5 The composite backplane CRB includes a first heat-conducting layer TC1, a backplane layer RPL, and a second heat-conducting layer TC2 that are sequentially stacked, and further includes a plurality of third heat-conducting layers TC3. Among them, the thermal conductivity of the material used for the first heat-conducting layer TC1, the thermal conductivity of the material used for the second heat-conducting layer TC2, and the thermal conductivity of the material used for the third heat-conducting layer TC3 are all greater than the thermal conductivity of the material used for the backplane layer RPL; the backplane layer RPL has a plurality of through holes TH corresponding one-to-one to the plurality of third heat-conducting layers TC3, and the third heat-conducting layer TC3 is located in the corresponding through hole TH and is connected to the first heat-conducting layer TC1 and the second heat-conducting layer TC2.

[0046] In this embodiment, a plurality of through holes TH are provided on the backplane layer RPL, and a third heat conduction layer TC3 is provided in each of the through holes TH. Moreover, a first heat conduction layer TC1 is provided on the side of the backplane layer RPL close to the display panel PNL, and a second heat conduction layer TC2 is provided on the side of the backplane layer RPL away from the display panel PNL. Thus, the thermal conductivity of the material used for the first heat conduction layer TC1, the thermal conductivity of the material used for the second heat conduction layer TC2, and the thermal conductivity of the material used for the third heat conduction layer TC3 are all greater than the thermal conductivity of the material used for the backplane layer RPL. Most of the heat generated by the display device can be quickly conducted through the first heat conduction layer TC1 to the third heat conduction layer TC3, and then quickly conducted through the third heat conduction layer TC3 to the second heat conduction layer TC2, and then quickly conducted through the second heat conduction layer TC2 to the heat dissipation area (for example, the application environment of the display device), improving the heat dissipation rate, avoiding the influence of temperature rise caused by untimely heat conduction and low heat dissipation efficiency on the overall display device, and further improving the performance and service life of the display device.

[0047] In one example, the elastic modulus of the backplane layer RPL is greater than the elastic modulus of the first heat conduction layer TC1, and the elastic modulus of the backplane layer RPL is greater than the elastic modulus of the third heat conduction layer TC3. That is to say, the backplane layer RPL has a high elastic modulus, high rigidity, and strong support for the display device, but there is a lack in heat conduction ability compared with the first heat conduction layer TC1 and the third heat conduction layer TC3. The first heat conduction layer TC1 and the third heat conduction layer TC3 have good heat conduction performance, but the support ability for the display device is insufficient. Thus, through the mutual cooperation of the first heat conduction layer TC1, the third heat conduction layer TC3 and the backplane layer RPL, the overall display device has high heat conduction ability and strong support ability.

[0048] In one example, the second heat conduction layer TC2 can be a graphite sheet layer. The thermal conductivity of the graphite sheet has direction specificity, and the thermal conductivity along the plane direction of the graphite sheet is very high, usually in the range of 1000 - 2000 W / (m·K), and can quickly conduct the heat transferred to the second heat conduction layer TC2 to the heat dissipation area. The graphite sheet has a low density, is light in weight, which is convenient for the lightweight of the display device, and the graphite sheet has good flexibility, enabling it to achieve good thermal contact on irregular structures.

[0049] In one example, the backplane layer RPL is made of stainless steel material.

[0050] In an embodiment of the present disclosure, as Figure 2 shown, the third heat conduction layer TC3 and the first heat conduction layer TC1 are made of the same material and integrally formed. That is to say, on the side of the backplane layer RPL close to the display panel PNL, an integrally formed first heat conduction layer TC1 and third heat conduction layer TC3 are provided, as Figure 2As described above, the third heat conduction layer TC3 can be understood as a boss on the side of the first heat conduction layer TC1 away from the display panel PNL. This boss penetrates through the through-hole TH on the backplane layer RPL and is connected to the second heat conduction layer TC2 to achieve rapid heat conduction. In this way, through an integrated molding process, the first heat conduction layer TC1 and the third heat conduction layer TC3 can be prepared using materials with high thermal conductivity, and in cooperation with the through-holes on the backplane layer RPL, the heat of the display device can be conducted from the first heat conduction layer TC1 and the third heat conduction layer TC3 to the second heat conduction layer TC2, improving the heat dissipation efficiency of the composite backplane CRB and the preparation process is simple.

[0051] In one example, the materials of the first heat conduction layer TC1 and the third heat conduction layer TC3 can be one of gold (thermal conductivity ~318 W / (m·K)), silver (thermal conductivity ~429 W / (m·K)), copper (thermal conductivity ~401 W / (m·K)), or aluminum (thermal conductivity ~237 W / (m·K)). It can be understood that the first heat conduction layer TC1 and the third heat conduction layer TC3 can also be other materials with high thermal conductivity.

[0052] In one implementation of the present disclosure, as Figure 3 shown, the third heat conduction layer TC3 is filled in the corresponding through-hole TH and fixed to the backplane layer RPL; the material of the third heat conduction layer TC3 is different from the materials of the first heat conduction layer TC1 and the second heat conduction layer TC2. That is to say, the backplane layer RPL and the third heat conduction layer TC3 form a composite support plate, and in this composite support plate, it includes the backplane layer RPL and the third heat conduction layer TC3 pre-embedded in the through-hole TH of the backplane layer RPL. In this way, when in use, the first heat conduction layer TC1, the composite support plate, and the second heat conduction layer TC2 can be directly stacked without further alignment, simplifying the assembly process of the composite backplane CRB.

[0053] In one example, the material of the third heat conduction layer TC3 can be one of gold, silver, copper, or aluminum. It can be understood that the third heat conduction layer TC3 can also be other materials with high thermal conductivity.

[0054] In one example, the first heat conduction layer TC1 can use a thermally conductive adhesive with excellent thermal conductivity, or other thermally conductive materials.

[0055] Exemplarily, first, through-holes can be formed on the backplane layer RPL, and then a material with a higher thermal conductivity than the backplane layer RPL is used to form the third heat conduction layer TC3 in the through-holes to obtain a composite support plate; then, the first heat conduction layer TC1 is formed on the side of the composite support plate close to the display panel PNL, and the second heat conduction layer TC2 is formed on the side of the composite support plate away from the display panel PNL to obtain the composite backplane CRB.

[0056] In an embodiment of the present disclosure, as Figure 4 shown, the first heat conduction layer TC1 includes a substrate portion TC11 and connection portions TC12 corresponding one-to-one to a plurality of the third heat conduction layers TC3. The connection portions TC12 are made of the same material as the corresponding third heat conduction layers TC3 and are integrally formed. The substrate portion TC11 has connection holes corresponding one-to-one to the respective connection portions TC12. The connection portions TC12 are received in the corresponding connection holes and are connected to the substrate portion TC11. That is to say, the substrate portion TC11 is a substrate located on the side of the backplane layer RPL close to the display panel PNL and having a plurality of connection holes; the connection portions TC12 and the third heat conduction layers TC3 are plug structures made of the same material and integrally formed. The plug structures penetrate through the connection holes and the through holes on the backplane layer RPL, and the connection portions TC12 are connected to the substrate portion TC11, and the third heat conduction layers TC3 are connected to the second heat conduction layer TC2. The thermal conductivity coefficients of the materials used for the substrate portion TC11 and the connection portions TC12 are both greater than that of the backplane layer RPL. In this way, most of the heat of the display device is transmitted to the second heat conduction layer TC2 through the connection portions TC12 and the third heat conduction layers TC3, or after the heat is transmitted to the substrate portion TC11, it is quickly transmitted to the connection portions TC12 through the substrate portion TC11, and then transmitted to the second heat conduction layer TC2, so that the heat is quickly discharged to the heat dissipation area, improving the heat dissipation efficiency of the composite backplane CRB.

[0057] In an embodiment of the present disclosure, as Figure 5 shown, the third heat conduction layer TC3 is disposed around the side wall of the corresponding through hole TH, and the third heat conduction layer TC3 forms a first cavity; the first heat conduction layer TC1 has second cavities AC2 corresponding one-to-one to and connected to the first cavities AC1; the first heat conduction layer TC1 and the third heat conduction layer TC3 are made of the same material and integrally formed. The cavities mentioned here can be annular cavities, rectangular cavities, or arc-shaped cavities, etc.

[0058] In one example, a single-film forming process is adopted to process the backplane layer RPL to prepare the first heat conduction layer TC1 and the third heat conduction layer TC3. For example, electroplating is used for single-film forming to form the first heat conduction layer TC1 on the surface of the backplane layer RPL and form the third heat conduction layer TC3 on the sidewall of the through hole TH. That is to say, the first heat conduction layer TC1 and the third heat conduction layer TC3 are an integral coating connected to each other, and a cavity that cannot be completely filled with the coating is formed at the position corresponding to the through hole TH. For example, in the through hole TH, the third heat conduction layer TC3 surrounds the sidewall of the through hole TH, and an annular cavity (the first cavity) is formed in the middle part of the third heat conduction layer TC3. In this way, the side of the first heat conduction layer TC1 away from the backplane layer RPL is connected to the display panel PNL, and most of the heat generated by the display device is quickly conducted through the first heat conduction layer TC1, the third heat conduction layer TC3, and the second heat conduction layer TC2 in sequence, thereby improving the heat dissipation efficiency.

[0059] In one example, as Figure 6 shown, a heat conduction connector CNT is arranged in the first cavity AC1 and the second cavity AC2. The heat conduction connector CNT is connected to both the first heat conduction layer TC1 and the third heat conduction layer TC3 at the same time, and the side of the heat conduction connector CNT away from the second heat conduction layer TC2 is connected to the display panel PNL, and the side of the heat conduction connector CNT close to the second heat conduction layer TC2 is connected to the second heat conduction layer TC2. That is to say, after the single-film forming process, materials with a thermal conductivity greater than that of the backplane layer RPL can be used to fill the first cavity AC1 and the second cavity AC2 to form the heat conduction connector CNT. In this way, the heat conduction connector CNT can directly conduct a part of the heat from the display device to the second heat conduction layer TC2, improving the overall heat dissipation efficiency of the composite backplane CRB.

[0060] The first heat conduction layer TC1 and the third heat conduction layer TC3 can be made of one of gold, silver, copper or aluminum. It can be understood that the third heat conduction layer TC3 can also be other materials with high thermal conductivity.

[0061] The heat conduction connector CNT can be made of thermal conductive glue or other materials with excellent thermal conductivity.

[0062] In an embodiment of the present disclosure, the total area of the orthographic projections of the through holes on the backplane layer RPL on the display panel PNL is 30% to 40% of the area of the orthographic projection of the backplane layer RPL on the display panel PNL. Further, the ratio of the area of the orthographic projection of the through holes on the backplane layer RPL on the display panel PNL to the area of the orthographic projection of the backplane layer RPL on the display panel PNL is 1:3. In this way, a high heat dissipation efficiency can be achieved through the third heat conduction layer TC3 in the through holes, and high support for the display device by the composite backplane CRB can be ensured.

[0063] In an embodiment of the present disclosure, the through hole TH is a circular hole (as Figure 7 shown), a rectangular hole (as Figure 8 shown), a strip hole (as Figure 9 shown), or an arc hole (as Figure 10 shown). It can be understood that through holes of other shapes can also be selected, and specifically, the shape and size of the appropriate through hole TH can be selected according to the actual application.

[0064] In an embodiment of the present disclosure, the backplane layer RPL includes a plurality of sub-regions, and the through hole distribution density of at least one of the sub-regions is different from that of other sub-regions. Exemplarily, as Figure 11 shown, taking the through hole TH as a circular hole as an example, the backplane layer RPL includes a first sub-region RPL1 and a second sub-region RPL2. The size of the through hole TH remains unchanged, and the setting density of the through hole TH in the first sub-region RPL1 is greater than that of the through hole TH in the second sub-region RPL2. That is, when the area corresponding to the first sub-region RPL1 on the display panel PNL generates more heat, the heat dissipation efficiency of this area can be improved by increasing the setting density of the through hole TH. In this way, under the condition of ensuring the support of the composite backplane CRB, the heat dissipation efficiency and heat dissipation uniformity of the display device are improved. In this example, the backplane layer RPL is divided into two sub-regions. It can be understood that according to the actual use scenario of the composite backplane CRB, the backplane layer RPL can be divided into more sub-regions as needed, for example, three sub-regions, four sub-regions, etc., to meet the support and heat dissipation of the composite backplane CRB by adjusting the setting density of the through hole TH.

[0065] In an embodiment of the present disclosure, the through hole size of at least one of the sub-regions is different from that of other sub-regions. Exemplarily, as Figure 12 shown, taking the through hole TH as a circular hole as an example, the backplane layer RPL includes a first sub-region RPL1 and a second sub-region RPL2. The setting density of the through hole TH remains unchanged, and the size of the through hole TH in the first sub-region RPL1 is greater than that of the through hole TH in the second sub-region RPL2. In this way, when the area corresponding to the first sub-region RPL1 on the display panel PNL generates more heat, the local heat dissipation efficiency of this area can be improved by increasing the size of the through hole TH, and further the overall heat dissipation uniformity of the display device is improved. In this example, the backplane layer RPL is divided into two sub-regions. It can be understood that according to the actual use scenario of the composite backplane CRB, the backplane layer RPL can be divided into more sub-regions as needed, for example, three sub-regions, four sub-regions, etc., to meet the support and heat dissipation of the composite backplane CRB by adjusting the size of the through hole TH.

[0066] In one example, takingFigure 13 Taking the orientation shown as an example, there are more connection leads arranged on the left side of the display panel PNL, and more heat is generated during operation. The setting density or the size of the through holes TH of the backplane layer RPL can be increased in the local area near the left side of the composite backplane CRB, so as to improve the local heat dissipation efficiency and make the heat dissipation efficiency of the entire display panel PNL more uniform.

[0067] After considering the specification and practicing the invention disclosed herein, those skilled in the art will readily conceive of other embodiments of the present disclosure. This application is intended to cover any variations, uses, or adaptations of the present disclosure, which follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

Claims

1. A composite backplane, located on the back side of a display panel, characterized in that: It includes a first heat-conducting layer, a back plate layer, and a second heat-conducting layer stacked in sequence, and also includes a plurality of third heat-conducting layers; wherein the thermal conductivity of the material used for the first heat-conducting layer, the thermal conductivity of the material used for the second heat-conducting layer, and the thermal conductivity of the material used for the third heat-conducting layer are all greater than the thermal conductivity of the material used for the back plate layer; The back plate layer has a plurality of through holes corresponding to the plurality of third heat-conducting layers one by one, and the third heat-conducting layers are located in the corresponding through holes and connected to the first heat-conducting layer and the second heat-conducting layer.

2. The composite backboard according to claim 1, characterized in that: The third heat-conducting layer is made of the same material as the first heat-conducting layer and is integrally formed.

3. The composite backboard according to claim 1, characterized in that: The third heat-conducting layer is filled in the corresponding through-hole and fixed to the back plate layer; the material of the third heat-conducting layer is different from the material of the first heat-conducting layer and the material of the second heat-conducting layer.

4. The composite back sheet according to claim 1, characterized in that: The first heat-conducting layer comprises a substrate portion and a connecting portion corresponding to the plurality of the third heat-conducting layers one by one, the connecting portion and the corresponding third heat-conducting layer are made of the same material and are integrally formed; The substrate portion has connection holes corresponding to the connection portions one by one, and the connection portions are accommodated in the corresponding connection holes and connected to the substrate portion.

5. The composite back sheet according to claim 1, characterized in that: The third heat-conducting layer is disposed around the sidewall of the corresponding through hole, and the third heat-conducting layer forms a first cavity; The first heat-conducting layer has a second cavity corresponding to and connected to the first cavity in a one-to-one manner; The first heat-conducting layer and the third heat-conducting layer are made of the same material and are integrally formed.

6. The composite backboard according to claim 5, characterized in that: The composite backplane also includes a heat-conducting connector filling the first cavity and the second cavity, and the thermal conductivity of the material used for the heat-conducting connector is greater than the thermal conductivity of the backplane layer.

7. The composite back sheet according to any one of claims 1 to 6, characterized in that: The elastic modulus of the back plate layer is greater than the elastic modulus of the first heat conducting layer, and the elastic modulus of the back plate layer is greater than the elastic modulus of the third heat conducting layer.

8. The composite back sheet according to any one of claims 1 to 6, characterized in that: The total area of ​​the orthographic projections of the through holes on the backplane layer on the display panel is 30% to 40% of the area of ​​the orthographic projections of the backplane layer on the display panel.

9. The composite back sheet according to claim 8, characterized in that: The backplane layer comprises a plurality of sub-regions, and the through-hole distribution density of at least one of the sub-regions is different from the through-hole distribution density of other sub-regions; Alternatively, a size of the through holes of at least one of the sub-regions is different from sizes of the through holes of other sub-regions.

10. A display device, characterized in that: It comprises a display panel and the composite backplane according to any one of claims 1 to 9.

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