Thermal conductivity and heat dissipation layer structure and display screen based on COB

Abstract

The present disclosure relates to a heat-conducting heat-spreading layer structure and a display screen based on COB, including a circuit board and a heat dissipation layer, wherein the heat dissipation layer is fixed on the circuit board and is provided with a plurality of first through holes, and the first through holes cooperate with the circuit board to accommodate LED illuminants. The above scheme provides a heat dissipation layer that can surround a plurality of LED areas, so that the temperature of each part on the circuit board is roughly the same, thereby avoiding the local temperature being too high, thereby affecting the luminous efficiency of the LED, and further causing color differences in each part of the LED display screen.

Description

Technical Field

[0001] The present disclosure relates to the field of printed circuit boards, and in particular to a COB-based heat-conducting and heat-spreading layer structure and a display screen. Background Art

[0002] COB is a display screen manufacturing process that directly solders LED chips on PCB boards. Currently, most COBs are made by directly covering the entire PCB with transparent resin or other materials after soldering the LED chips to protect the LED chips and their gold wires from external damage. However, transparent resins have poor heat dissipation capabilities and are not conducive to LED light emission. Summary of the invention

[0003] The present disclosure provides a COB-based heat-conducting heat-spreading layer structure and a display screen to solve at least one defect of the prior art.

[0004] In a first aspect, the present disclosure provides a COB-based thermal conductive heat-dissipating layer structure, comprising a circuit board and a heat dissipation layer, wherein the heat dissipation layer is fixed on the circuit board and is provided with a plurality of first through holes, wherein the first through holes cooperate with the circuit board to accommodate LED light-emitting bodies.

[0005] In some embodiments, the outer surface of the heat dissipation layer is made of a conductive material, and the heat dissipation layer may be connected to the ground.

[0006] In some embodiments, the heat dissipation layer is provided with a grounding conductor, and the heat dissipation layer can be connected to the ground through the grounding conductor.

[0007] In some embodiments, the heat dissipation layer is electrically connected to a ground circuit of the circuit board.

[0008] In some embodiments, the circuit board is provided with a conductive layer, the heat dissipation layer is electrically connected to the conductive layer, and the conductive layer is electrically connected to a ground circuit of the circuit board, so that the heat dissipation layer is electrically connected to the ground circuit.

[0009] In some embodiments, the heat dissipation layer may be made of metal or alloy; or the heat dissipation layer includes an intermediate layer and a metal layer or an alloy layer covering the outside of the intermediate layer.

[0010] In some embodiments, the heat dissipation layer includes a plurality of heat dissipation plates disposed at different positions on the circuit board, and the heat dissipation plates are provided with a plurality of first through holes.

[0011] In some embodiments, at least two heat sinks are connected to each other.

[0012] In some embodiments, all heat sinks are interconnected.

[0013] In some embodiments, the heat sink may be made of metal or alloy; or the heat sink includes an intermediate layer and a metal layer or an alloy layer covering the intermediate layer.

[0014] A second aspect provides a display screen, comprising a plurality of LED illuminants and a COB-based heat-conducting and heat-spreading layer structure according to any of the above embodiments, wherein the LED illuminants are arranged on the circuit board and located in the first through holes.

[0015] In some embodiments, the LED light-emitting body includes a plurality of light-emitting chips, and part or all of the side walls of the light-emitting chips abut against the inner wall of the first through hole.

[0016] In some embodiments, the first through hole is filled with a thermally conductive material, and the thermally conductive material wraps the LED light emitter.

[0017] In some embodiments, the LED light-emitting body includes a plurality of light-emitting chips, and the thermal conductive material wraps the light-emitting chips.

[0018] In some embodiments, the thermally conductive material is a thermally conductive and light-transmitting material.

[0019] In some embodiments, the LED illuminant corresponds to the first through hole one by one. Beneficial effect: This solution sets a heat dissipation layer that can surround multiple LED areas, so that the temperature of each part of the circuit board is roughly the same, avoiding the local temperature being too high, which leads to inconsistent attenuation of the luminous efficiency of different LED light-emitting chips, and then causes color differences in various parts of the LED display screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a display screen in the first embodiment of the present disclosure.

[0021] Figure 2 It is a schematic structural diagram of the heat dissipation layer in the first embodiment of the present disclosure.

[0022] Figure 3 It is a schematic diagram of the structure of the circuit board in the first embodiment of the present disclosure.

[0023] Figure 4 Schematic diagram of the cross-sectional structure of the display screen in the first embodiment of the present disclosure.

[0024] Figure 5 Schematic diagram of the cross-sectional structure of the heat dissipation layer in the second embodiment of the present disclosure.

[0025] Figure 6 Schematic diagram of the cross-sectional structure of a display screen in the fourth embodiment of the present disclosure.

[0026] Figure 7It is a schematic diagram of the cross-sectional structure of the circuit board in the fifth embodiment of the present disclosure.

[0027] Figure 8 It is a schematic diagram of the cross-sectional structure of the circuit board in the sixth embodiment of the present disclosure (with an insulating layer).

[0028] Among them, 1, circuit board; 11, insulation layer; 12, conductive layer; 2, heat dissipation layer; 21, first through hole; 23, scattering part; 3, LED light-emitting body; 31, LED light-emitting chip. DETAILED DESCRIPTION

[0029] It should be understood that the exemplary embodiments described herein should be considered only for descriptive purposes and not for limiting purposes. Descriptions of features or aspects in each exemplary embodiment should generally be considered applicable to similar features or aspects in other exemplary embodiments.

[0030] The above description is provided with reference to the accompanying drawings to facilitate a comprehensive understanding of the various embodiments of the invention as defined by the claims. It contains various specific details to facilitate such understanding, but these details should be regarded as exemplary only. Accordingly, those of ordinary skill in the art will recognize that changes and improvements may be made to the various embodiments described herein without departing from the scope of the invention as defined by the appended claims. In addition, for the sake of clarity and brevity, descriptions of well-known functions and configurations may be omitted.

[0031] The terms and words used in the following description and claims are not limited to the written meanings, but are merely used by the inventor to allow a clear and consistent understanding of the present invention. Accordingly, it will be apparent to those skilled in the art that the following description of various embodiments of the present invention is provided for the purpose of explanation only and not for the purpose of limiting the present invention as defined by the appended claims.

[0032] Throughout the specification and claims of this application document, the words "include" and "comprise" and word variations, such as "comprising" and "including" mean "including but not limited to", and are not intended to (and will not) exclude other components, integers or steps.

[0033] Features, integers or characteristics described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

[0034] It should be understood that the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. In the present invention, the expression "or" includes any or all combinations of the terms listed together. For example, "A or B" may include A or B, or may include both A and B.

[0035] Although expressions such as "first" and "second" may be used to describe the various elements of the present invention, they are not intended to limit the corresponding elements. For example, the above expressions are not intended to limit the order or importance of the corresponding elements. The above expressions can be used to distinguish one component from another component. For example, the first pixel unit and the second pixel unit are both pixel units and represent different pixel units. For example, without departing from the scope of the present invention, the first pixel unit can be referred to as the second pixel unit, and similarly, the second pixel unit can be referred to as the first pixel unit.

[0036] The terminology used in the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention. Unless otherwise specified, all terms used herein (including technical terms and scientific terms) have the same meanings as those commonly understood by those of ordinary skill in the technical field to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having meanings consistent with the context of the relevant field and this specification, and should not be interpreted in an idealized or overly formalized sense, unless explicitly defined in this article.

[0037] Figure 1 is a schematic diagram of a display screen in a first embodiment of the present disclosure, such as Figure 1 As shown, the display screen includes a plurality of LED light emitters 3 and a heat-conducting and heat-spreading layer structure based on COB. The heat-conducting and heat-spreading layer structure based on COB includes a circuit board 1 and a heat-dissipating layer 2, wherein the bottom of the heat-dissipating layer 2 is fixed to the top of the circuit board 1 by soldering. It should be understood that in addition to being connected to the circuit board 1 by soldering, the heat-dissipating layer 2 can also be connected to the circuit board 1 by structures such as adhesives, buckles, bolts or bolts.

[0038] and Figure 2 FIG. 4 shows a schematic diagram of the structure of the heat dissipation layer in the first embodiment. Figure 1 and Figure 2 As shown, the heat dissipation layer 2 is provided with a plurality of first through holes 21, and the first through holes 21 are arranged in an array. Figure 1 The array arrangement of the first through holes 21 shown is only exemplary. In alternative embodiments, the arrangement of the first through holes 21 may be selected according to specific occasions. In other embodiments, the arrangement shape of the first through holes 21 may be, but is not limited to: Figure 1 and Figure 2 The shape shown in the figure can be alternatively set to a rectangular, circular, elliptical or other shape with a certain pattern; or it is not limited to a flat surface, but a curved screen shape.

[0039] Figure 3FIG. 1 shows a schematic diagram of the structure of a circuit board in a first embodiment of the present disclosure. Figure 3 As shown, the LED illuminator 3 is arranged on the top of the circuit board 1 by welding. And each LED illuminator 3 includes three LED light-emitting chips 31. In addition, the three light-emitting chips in each LED illuminator 3 correspond to three red, green and blue LED chips of the three primary colors of RGB. It should be understood that in other embodiments, according to actual application needs, the LED illuminator 3 may include any other number and color of LED light-emitting chips 31, such as but not limited to one LED light-emitting chip 31, two LED light-emitting chips 31 or more LED light-emitting chips 31, and such as but not limited to the same color LED light-emitting chips 31, different color LED light-emitting chips 31, three primary color LED light-emitting chips 31, other color LED light-emitting chips 31 and combinations thereof. For example, in the case of a screen that only needs to display text or simple graphics, it is possible to select each LED illuminator 3 to include a single-color LED chip, or it is possible to select each LED illuminator 3 to include two LED light-emitting chips 31 with different colors.

[0040] Please refer to Figure 4 And continue to refer to Figure 1 , each LED illuminant 3 is located in the first through hole 21 of the heat dissipation layer 2, the number corresponds to the position, and is arranged in a 10*10 array. However, in other embodiments, the first through hole 21 may include a plurality of LED illuminants 3, such as two, three or four, etc., and there is no limitation on the number, as long as the LED illuminant 3 is located in the first through hole 21.

[0041] It should be understood that if Figure 4 As shown in FIG. 1 , since the LED luminous body 3 is located in the first through hole 21, the top of the LED luminous body 3 is lower than the top of the first through hole 21. Therefore, the light emitted by the LED luminous body 3 is limited by the first through hole 21, and the light emission direction and angular distribution of the LED luminous body 3 can be adjusted by the shape of the first through hole 21. Figure 4 As shown, the first through hole 21 is a symmetrical bowl-shaped structure, but in actual production, the shape of the first through hole 21 can be adjusted as needed to cope with different environments, such as Figure 5 As shown, the first through hole can be set to an asymmetric shape to reflect the light originally emitted from the top to the bottom, thereby adjusting the light emission angle and direction of the LED light emitting body 3. Alternatively, the first through hole 21 can be set to a parabola shape as needed.

[0042] The applicant discovered in practice that due to the combined effect of various factors, when the LED display screen is working, the accumulated heat in various parts of the display screen is not uniform, but each pixel of the LED display screen is composed of three LED chips, red, green, and blue. The influence of temperature on the luminous efficiency of the chip is different, which leads to different attenuation ratios of the luminous efficiency of the three LED chips, red, green, and blue, and ultimately leads to color differences between various positions of the LED display screen. Therefore, the present disclosure proposes a new COB-based thermal conductive heat-sinking layer structure and a corresponding display screen. In this structure, the heat dissipation layer 2 is connected to multiple LED illuminants 3 areas (referring to the areas where the LED illuminants 3 are placed in the heat-sinking layer structure), so that the heat of multiple LED luminous areas can be transferred to each other through the heat dissipation layer 2, reducing the problem of uneven temperature in multiple LED luminous areas.

[0043] In some embodiments, the outer surface of the heat dissipation layer 2 is made of a conductive material, so that the outer surface of the heat dissipation layer is conductive, and the heat dissipation layer is connected to the ground. Thus, in addition to the heat dissipation effect, the heat dissipation layer also has the ability of electromagnetic shielding. The above scheme grounds the heat dissipation layer 2, so that the heat dissipation layer 2 becomes an electrostatic shielding body, so that the electric field terminates on the metal surface of the electrostatic shielding body, and transfers the charge to the ground, thereby achieving the effect of electromagnetic shielding and eliminating static electricity.

[0044] In some embodiments, the heat dissipation layer 2 can be first injection molded by other plastic materials, and then a metal layer is plated on its surface, so that it has heat dissipation and electrical conductivity. Of course, in some embodiments, the heat dissipation layer 2 can be directly prepared with metal or alloy. Or other thermally conductive materials with conductive properties can be used to replace the metal layer 2. By providing a metal outer layer or being composed of metal, the heat dissipation layer 2 has a high electrical conductivity in addition to a strong thermal conductivity, which is beneficial to its heat dissipation. And the thermal expansion coefficient of metal or alloy is closer to the thermal expansion coefficient of PCB circuit board 1 than that of resin (PCB is 14-17ppm / ℃, metal is 10-24ppm / ℃, and typical epoxy resin is 64ppm / ℃), which can effectively reduce the problems of changes in light emission effect, stress pulling, etc. caused by inconsistent thermal expansion of the two materials during the use of the display screen. The metals used in the heat dissipation layer 2 include but are not limited to copper and aluminum.

[0045] It should be understood that although Figure 1 and Figure 2 The heat dissipation layer 2 shown in the figure is an integrally formed whole-layer structure, and optionally, the material of the heat dissipation layer 2 can be a structure with good thermal and electrical conductivity such as metal or alloy; or the heat dissipation layer 2 includes an intermediate layer, and a metal layer or alloy layer covering the outside of the intermediate layer.

[0046] In some embodiments, the heat dissipation layer 2 includes a plurality of heat dissipation plates arranged at different positions of the circuit board 1, and the heat dissipation plates are provided with a plurality of first through holes. It should be understood that a plurality of heat dissipation plates can be used according to the situation, and each heat dissipation plate is provided with a plurality of first through holes, and the heat dissipation plate can directly abut against the light-emitting chip 31 in the first through hole, or a heat-conducting material can be arranged in the first through hole, so that the light-emitting chip 31 and the heat dissipation plate can quickly exchange heat through the heat-conducting material. Each heat dissipation plate can balance the heat of the light-emitting chip 31 located in its first through hole. In some optional embodiments, a plurality of heat dissipation plates can be connected together to achieve a larger range of heat dissipation and heat distribution.

[0047] Furthermore, all the heat sinks can be connected to each other. The heat sink can be made of a metal or alloy with good thermal and electrical conductivity; or the heat sink includes an intermediate layer and a metal layer or alloy layer covering the intermediate layer.

[0048] There are various ways to ground the heat dissipation layer 2, such as Figure 7 As shown, the circuit board 1 is provided with a conductive layer 12, the heat dissipation layer 2 is electrically connected to the conductive layer 12, and the conductive layer 12 is electrically connected to the ground circuit of the circuit board 1, so that the heat dissipation layer 2 and the ground circuit are indirectly electrically connected through the conductive layer 12. Optionally, the conductive layer 12 is located between the circuit board 1 and the heat dissipation layer 2. It should be understood that one or more conductive layers 12 can be provided on the circuit board, such as Figure 7 As shown, a whole conductive layer 12 is provided on the circuit board 1, and the conductive layer 12 covers most of the upper surface of the circuit board. In some optional embodiments, Figure 8 As shown, a plurality of conductive layers 12 are provided on the circuit board, and the plurality of conductive layers 12 are electrically connected to the heat dissipation layer. Moreover, a portion of the upper surface of the circuit board 1 is covered by the conductive layer 12, while another portion is exposed from the conductive layer 12. A connection structure such as bolts, adhesives, and buckles can be provided on the exposed portion to connect the circuit board 1 and the heat dissipation layer 2.

[0049] In addition to the above-mentioned methods, the grounding method of the heat dissipation layer can also be: the heat dissipation layer 2 is provided with a grounding conductor, and the heat dissipation layer 2 can be connected to the ground through the grounding conductor. It should be understood that the grounding conductor can be a grounding wire, a grounding circuit or a grounding metal structure.

[0050] Alternatively, the circuit board 1 is provided with a first conductive portion, the first conductive portion is electrically connected to the ground circuit of the circuit board 1, and the heat dissipation layer 2 is provided with a second conductive portion, the first conductive portion is electrically connected to the second conductive portion. More specifically, the first conductive portion is a concave structure on the circuit board 1, the second conductive portion is a convex structure, and the first conductive portion and the second conductive portion abut against each other, so that the heat dissipation layer 2 is electrically connected to the ground circuit of the circuit board 1.

[0051] It should be understood that there are many ways to ground the heat dissipation layer, including but not limited to the above-mentioned solutions, and users can select and adjust according to their needs.

[0052] In some embodiments, the first through hole 21 is filled with a thermally conductive material, so the thermally conductive material abuts against the side wall of the first through hole 21 (i.e., abuts against the heat dissipation layer 2), and the thermally conductive material wraps the LED light-emitting body 3. More specifically, the LED light-emitting body 3 includes three light-emitting chips, and the thermally conductive material wraps the light-emitting chip. Since the thermally conductive material wraps the light-emitting chip, the heat of the light-emitting chip can be directly transferred to the thermally conductive material, and the heat is directly transferred to the heat dissipation layer 2 by the thermally conductive material. In this way, the heat can not only be dissipated faster, but also the temperature of each part of the circuit board 1 is more uniform due to the effect of the heat dissipation layer 2, ensuring the consistency of the screen color. In addition, since the thermally conductive material is not only connected to the LED light-emitting body 3, but more importantly, it is connected to each LED light-emitting chip 31 in the LED, so that each LED light-emitting chip 31 can directly transfer heat through the thermally conductive material, further improving the heat dissipation effect. Optionally, the thermally conductive material can be a thermally conductive and light-transmitting material, such as a thermally conductive and light-transmitting silicone.

[0053] In some embodiments, the heat emitted by the LED light-emitting chip 31 can be transferred to the heat dissipation layer 2 through the heat-conducting and light-transmitting material in the first through hole 21. Since the outer layer of the heat dissipation layer 2 is a metal layer, the heat can be quickly transferred out, resulting in a heat dissipation effect. At the same time, since the LED light-emitting chips 31 on the circuit board quickly transfer heat to the heat dissipation layer 2 in a similar manner, the temperature of the LED light-emitting chips 31 on the circuit board is roughly the same, reducing the temperature difference between them, and ensuring that the color of the LED display screen is roughly the same everywhere. In addition, since the first through hole 21 is filled with a heat-conducting and light-transmitting silicone material, it will not hinder the LED chip 31 from emitting light.

[0054] Moreover, in some embodiments, the thermal conductive material may not completely wrap the LED light-emitting chip 31, but only wrap the bottom of the LED light-emitting chip 31, so that the bottom of the LED light-emitting chip 31 is indirectly connected to the inner wall of the first through hole 21 through the thermal conductive material, which facilitates the heat dissipation of the LED light-emitting chip 31 while ensuring that the upper surface of the LED light-emitting chip 31 will not be obstructed by the opaque thermal conductive material.

[0055] It should be understood that, in addition to the first through hole 21 being in contact with the LED light-emitting chip 31 through the heat-conducting material, in some embodiments, the side walls of the multiple LED light-emitting chips 31 in the LED light-emitting body 3 are in contact with the inner wall of the first through hole 21, so that the heat of the LED light-emitting chip 31 can be directly transferred through the heat dissipation layer 2, and the temperature of each LED light-emitting chip 31 on the circuit board 1 can also be ensured to be roughly the same. In addition, when the first through hole 21 is set, the inner wall of the first through hole 21 close to the circuit board 1 can be in contact with the light-emitting chip 31, and at the same time, the inner wall of the first through hole 21 far from the circuit board 1 forms a symmetrical bowl shape and a parabola shape, etc., to control the direction and angle of light emitted by the light-emitting chip 31.

[0056] In order to better mix and diffuse the light emitted by the LED light emitting body 3 , in some embodiments, a scattering portion 23 may be provided in the first through hole 21 .

[0057] In some embodiments, the first through hole 21 may use a scattering portion 23, specifically, Figure 6 As shown, the outer surface of the scattering portion 23 is arched in the direction away from the LED light-emitting chip 31, and the side of the scattering portion 23 forms a substantially flat outer wall. Adjacent scattering portions 23 are combined by affixing the substantially flat outer walls of the scattering portions 23 together. Of course, in some embodiments, different scattering portions 23 do not necessarily need to be completely affixed, and there may be a certain distance between different scattering portions 23. The structure of the scattering portion 23 can even be adjusted according to actual needs, such as adjusting it into a hemispherical, cubic, or other structure, and is not necessarily limited to the following structures. Figure 6 The structure shown.

[0058] Meanwhile, it should be understood that the scattering portion 23 includes scattering materials, and thus has a certain ability to mix and diffuse light.

[0059] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure is described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art without making creative efforts are within the scope of protection of the present disclosure.

Claims

1. A display screen, characterized in that: It includes multiple LED light-emitting bodies and a COB-based thermally conductive and heat-absorbing layer structure, wherein the COB-based thermally conductive and heat-absorbing layer structure includes a circuit board and a heat dissipation layer, the heat dissipation layer is fixed on the circuit board, and the heat dissipation layer is provided with multiple first through holes, the first through holes cooperate with the circuit board to accommodate the LED light-emitting bodies, the outer surface of the heat dissipation layer is made of conductive material, the heat dissipation layer is connected to the ground, the top height of the LED light-emitting body is lower than the top of the first through hole, the light emitted by the LED light-emitting body will be limited by the first through hole, the LED light-emitting body is arranged on the circuit board and located in the first through hole, the first through hole is filled with a thermally conductive material, and the thermally conductive material wraps the LED light-emitting body.

2. The display screen according to claim 1, characterized in that: The heat dissipation layer is provided with a grounding conductor, and the heat dissipation layer is connected to the ground through the grounding conductor.

3. The display screen according to claim 1, characterized in that: The heat dissipation layer is electrically connected to a ground circuit of the circuit board.

4. The display screen according to claim 3, characterized in that: The circuit board is provided with a conductive layer, the heat dissipation layer is electrically connected to the conductive layer, and the conductive layer is electrically connected to a grounding circuit of the circuit board, so that the heat dissipation layer is electrically connected to the grounding circuit.

5. The display screen according to any one of claims 1 to 4, characterized in that: The heat dissipation layer is made of metal or alloy; or The heat dissipation layer includes an intermediate layer and a metal layer or an alloy layer covering the outside of the intermediate layer.

6. The display screen according to claim 1, characterized in that: The heat dissipation layer comprises a plurality of heat dissipation plates arranged at different positions of the circuit board, and the heat dissipation plates are provided with a plurality of first through holes.

7. The display screen according to claim 6, characterized in that: At least two heat sinks are connected to each other.

8. The display screen according to claim 7, characterized in that: All heat sinks are connected to each other.

9. The display screen according to any one of claims 6 to 8, characterized in that: The heat sink is made of metal or alloy; or The heat sink comprises an intermediate layer and a metal layer or an alloy layer covering the outside of the intermediate layer.

10. The display screen according to claim 1, characterized in that: The LED illuminant includes a plurality of light-emitting chips, and part or all of the side walls of the light-emitting chips abut against the inner wall of the first through hole.

11. The display screen according to claim 1, characterized in that: The LED illuminant comprises a plurality of light-emitting chips, and the heat-conductive material wraps the light-emitting chips.

12. The display screen according to claim 11, characterized in that: The heat-conducting material is a heat-conducting and light-transmitting material.

13. The display screen according to any one of claims 10 to 12, characterized in that: The LED illuminators correspond to the first through holes one by one.

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