Efficient heat dissipation CSP backlight source structure

Abstract

The utility model relates to the technical field of backlight of display equipment, and provides a CSP (Chip Scale Package) backlight source structure with efficient heat dissipation, which comprises a circuit substrate with a first surface; the plurality of CSP light sources are arranged on the first surface, and the outer side of each CSP light source is covered with an optical lens layer; the heat dissipation layer is arranged between the circuit substrate and the CSP light source; the heat dissipation layer makes contact with the CSP light source and extends to the outer side of the optical lens layer so as to dissipate heat of the CSP light source. The problem that the performance of a light-emitting chip is reduced due to the fact that an existing CSP light source is poor in heat dissipation is solved.

Description

Technical Field

[0001] This utility model relates to the field of display device backlight technology, and more specifically, to a CSP backlight structure with high-efficiency heat dissipation. Background Technology

[0002] CSP (Chip Scale Package) packaging, or chip-level packaging, is used to form CSP light sources. CSP light sources are a type of LED device, and their core feature is that a flip-chip structure is encapsulated with phosphor or phosphor colloid film. This eliminates most of the packaging steps and structures required for traditional LED light sources, significantly reducing the package size to 1 / 5 to 1 / 10 of the original. Due to its excellent light extraction efficiency and color uniformity, compact size, and good heat dissipation structure, CSP light sources are increasingly being used in high-end fields such as mobile phone flashlights, automotive headlights, display backlights, and commercial lighting. Currently, with the continuous development of CSP packaging technology, backlight structures based on CSP devices are favored in fields such as display backlighting, and their application in display backlighting is becoming increasingly widespread.

[0003] Using CSP (Concentrated SP) light sources as backlights for display devices generates heat not only from the LED chip itself but also from the phosphor emitting yellow-green light during downconversion. Research shows that when the surface temperature of the LED chip exceeds 150 degrees Celsius, the luminous efficiency of the CSP light source decreases significantly, and the phosphor colloid is prone to cracking. As the chip temperature rises, the silicone material is also prone to deformation and aging. However, existing CSP light sources are typically directly soldered onto the circuit board, resulting in poor heat dissipation and impacting the performance of the LED chip.

[0004] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0005] The purpose of this invention is to provide a CSP backlight structure with high-efficiency heat dissipation, which solves the problem of poor heat dissipation in existing CSP light sources, leading to reduced performance of the light-emitting chip.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] This utility model provides a high-efficiency heat dissipation CSP backlight structure, including: a circuit board, the circuit board having a first surface;

[0008] Multiple CSP light sources are disposed on the first surface, and each CSP light source is covered with an optical lens layer on its outer side;

[0009] A heat dissipation layer is disposed between the circuit board and the CSP light source;

[0010] The heat dissipation layer is in contact with the CSP light source and extends to the outside of the optical lens layer to dissipate heat from the CSP light source.

[0011] In one embodiment, the CSP light source includes: a light-emitting chip, and a phosphor layer covering the light-emitting chip;

[0012] The heat dissipation layer includes: a chip contact portion, which is located between the light-emitting chip and the circuit board. A clearance hole is provided on the chip contact portion, and the electrodes of the light-emitting chip pass through the clearance hole and are fixedly connected to the circuit board.

[0013] The adhesive layer contact portion is connected to the outside of the chip contact portion and is in contact with the fluorescent adhesive layer;

[0014] The outer extension is connected to the adhesive layer contact portion and is located on the outside of the optical lens layer.

[0015] In one embodiment, the fluorescent adhesive layer includes: an end face cover portion that covers the front side of the light-emitting chip;

[0016] The side heat-conducting part surrounds the outer edge of the connecting end face cover and extends toward the circuit board. The side heat-conducting part is located on the outside of the light-emitting chip and abuts against the adhesive layer contact part.

[0017] In one embodiment, the thickness of the side heat-conducting portion gradually increases along the direction of the end face covering portion toward the circuit board.

[0018] In one embodiment, an inner fluorescent layer is disposed inside the fluorescent adhesive layer, and the inner fluorescent layer is located between the end face cover and the light-emitting chip.

[0019] In one embodiment, the phosphor mass percentage of the fluorescent adhesive layer is less than that of the phosphor mass percentage of the inner fluorescent layer.

[0020] In one embodiment, the outer extension is bent outwards from the outer side of the optical lens layer.

[0021] In one embodiment, the curved outer extension includes at least one arcuate segment, and at least one arcuate segment forms a vent hole between itself and the circuit board.

[0022] In one embodiment, the outer extensions of the heat dissipation layer are spaced apart to form independent units, and are respectively matched with multiple CSP light sources;

[0023] or,

[0024] The outer extensions of the heat dissipation layer are connected to form a whole, and multiple CSP light sources are distributed on the whole heat dissipation layer.

[0025] In one embodiment, the heat dissipation layer is a thermally conductive insulating sheet.

[0026] The beneficial effects of the CSP backlight structure with high-efficiency heat dissipation provided by this utility model are at least as follows: By setting multiple CSP light sources on the first surface of the circuit board and covering the outside of each CSP light source with an optical lens layer, the optical lens layer is used to process the emitted light to achieve predetermined requirements and improve the illumination performance. By setting a heat dissipation layer between the circuit board and the CSP light source, the heat dissipation layer is in contact with the CSP light source and extends to the outside of the optical lens layer. The heat generated during the light emission process of the CSP light source can be conducted through the heat dissipation layer and thus discharged to the outside of the optical lens layer, thereby achieving timely heat dissipation of the CSP light source. By improving the heat dissipation efficiency of the CSP light source, the continuous and stable light emission of the CSP light source under high light emission performance is ensured. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A partial cross-sectional view of a light source structure for a high-efficiency heat dissipation CSP backlight structure provided in an embodiment of this utility model;

[0029] Figure 2 A partial cross-sectional view of another light source structure for a high-efficiency heat dissipation CSP backlight structure provided in this embodiment of the utility model;

[0030] Figure 3 A partial cross-sectional view of a heat dissipation layer structure of a high-efficiency heat dissipation CSP backlight structure provided in an embodiment of this utility model;

[0031] Figure 4 This is a partial cross-sectional view of another heat dissipation layer structure for a high-efficiency heat dissipation CSP backlight structure provided in an embodiment of the present invention.

[0032] The following are the labeling elements in the figure:

[0033] 100 Circuit board; 200 CSP light source; 210 Light-emitting chip; 211 Electrode; 220 Phosphor adhesive layer; 221 End face cover; 222 Side heat-conducting part; 230 Inner phosphor layer; 300 Heat dissipation layer; 310 Chip contact part; 320 Adhesive layer contact part; 330 Outer extension part; 331 Arc segment; 332 Vent hole; 400 Optical lens layer. Detailed Implementation

[0034] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0035] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it may be directly or indirectly located on that other component. When a component is referred to as "connected to" another component, it may be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate orientations or positions based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly defined.

[0036] like Figure 1 , Figure 2As shown, the high-efficiency heat dissipation CSP backlight structure of this embodiment mainly includes: a circuit board 100, multiple CSP light sources 200, and a heat dissipation layer 300. Corresponding control circuits are disposed on the circuit board 100. The circuit board 100 has a first surface, which is referred to as the upper surface for ease of structural description. Pads are disposed on the upper surface, and the electrodes 211 of the multiple CSP light sources 200 are respectively soldered and fixed to the pads on the circuit board 100, thereby fixing the multiple CSP light sources 200 to the upper surface of the circuit board 100. An optical lens layer 400 (transparent lens) covers the outer side of each CSP light source 200. The CSP light source 200 is electrically connected to the control circuit on the circuit board 100 and can emit light when powered on. The optical lens layer 400 covering the CSP light source 200 allows the CSP light source 200 to have a larger emission angle and emit high color gamut white light. By using multiple CSP light sources 200 on the circuit board 100, a backlight module can be formed, thereby providing backlight for the display device and enabling the display device to perform its display function. A heat dissipation layer 300 is disposed between the circuit board 100 and the CSP light source 200. The heat dissipation layer 300 can cover the surface of the circuit board 100 and is in contact with the CSP light source 200, thereby realizing heat conduction to the CSP light source 200. Moreover, the heat dissipation layer 300 extends to the outside of the optical lens layer 400, so that part of the inner area of ​​the heat dissipation layer 300 is located inside the CSP light source 200 and the outer area is located outside the CSP light source 200. In this way, the heat generated by the CSP light source 200 during the light emission process can be conducted to the outside of the CSP light source 200 in a timely manner, achieving more efficient heat dissipation.

[0037] like Figure 1 , Figure 2 As shown, the working principle of the high-efficiency heat dissipation CSP backlight structure provided in this embodiment is as follows: Multiple CSP light sources 200 are disposed on the first surface of the circuit board 100, and an optical lens layer 400 is covered on the outside of each CSP light source 200. The optical lens layer 400 processes the emitted light to achieve predetermined requirements, improving the illumination performance of the CSP light source 200 and expanding the emission angle. A heat dissipation layer 300 is disposed between the circuit board 100 and the CSP light source 200. The heat dissipation layer 300 contacts the CSP light source 200 and extends to the outside of the optical lens layer 400. The heat generated during the emission of the CSP light source 200 can be conducted through the heat dissipation layer 300, thereby dissipating heat to the outside of the optical lens layer 400, achieving timely heat dissipation of the CSP light source 200. This reduces the temperature of the CSP light source 200, avoiding problems such as reduced luminous efficiency and internal cracking damage. By improving the heat dissipation efficiency of the CSP light source 200, continuous and stable emission of the CSP light source 200 under high luminous performance is ensured.

[0038] like Figure 1 As shown, the CSP light source 200 in this embodiment further includes a light-emitting chip 210 and a phosphor layer 220. The bottom of the light-emitting chip 210 has an electrode 211, and the phosphor layer 220 covers the light-emitting surface of the light-emitting chip 210. The light-emitting chip 210 emits light when powered on, and the emitted light is converted into yellow-green light by the phosphor in the phosphor layer 220. Finally, after light mixing, it can achieve the effect of emitting white light.

[0039] like Figure 1 As shown, the heat dissipation layer 300 in this embodiment can be a sheet-like structure, divided into different functional areas on the plane according to its different placement positions. For ease of structural description, the center of the light-emitting chip 210 is taken as the center, the direction towards the center is inward, and the direction away from the center is outward. Therefore, the heat dissipation layer 300 specifically includes: a chip contact portion 310, an adhesive layer contact portion 320, and an outer extension portion 330. The chip contact portion 310 is located between the light-emitting chip 210 and the circuit board 100. The chip contact portion 310 is the area directly below the light-emitting chip 210. A clearance hole is formed on the chip contact portion 310. The electrode 211 of the light-emitting chip 210 passes through the clearance hole and is fixedly connected to the circuit board 100. In this way, after the heat dissipation layer 300 covers the circuit board 100, it does not affect the light-emitting function of the light-emitting chip 210. The adhesive layer contact portion 320 is connected to the outside of the chip contact portion 310, and the adhesive layer contact portion 320 is located directly below the phosphor adhesive layer 220 on the outside of the light-emitting chip 210, so that the adhesive layer contact portion 320 can contact the phosphor adhesive layer 220. The outer extension portion 330 is connected to the adhesive layer contact portion 320 and is located outside the adhesive layer contact portion 320, and the outer extension portion 330 continues to extend outward by a predetermined distance, thus protruding outside the entire orthogonal projection area of ​​the optical lens layer 400 on the circuit board 100. Therefore, the outer extension portion 330 is located outside the light source structure formed by the CSP light source 200 and the optical lens layer 400. The heat generated by the light-emitting chip 210 is conducted outward through the chip contact portion 310, and at the same time, the heat generated by the phosphor adhesive layer 220 is also conducted outward through the adhesive layer contact portion 320. The heat is conducted to the outer extension portion 330 located on the outside, so that the outer extension portion 330 can exchange heat with the cold air outside the light source structure, thereby improving the heat dissipation efficiency of the CSP structure and achieving efficient heat dissipation.

[0040] like Figure 1As shown, in this embodiment, the fluorescent adhesive layer 220 further includes an end-face covering portion 221 and a side heat-conducting portion 222. The end-face covering portion 221 covers the front side of the light-emitting chip 210, and the side heat-conducting portion 222 surrounds the outer edge of the end-face covering portion 221 and extends toward the circuit board 100. The side heat-conducting portion 222 is located outside the light-emitting chip 210 and abuts against the adhesive layer contact portion 320. The fluorescent adhesive layer 220 forms a "︹" shaped structure, covering the light-emitting chip 210 in the middle. The end-face covering portion 221 is located directly above the light-emitting chip 210, and the side heat-conducting portion 222 is located outside the light-emitting chip 210. The fluorescent adhesive layer 220 contains phosphor, which converts the light emitted by the light-emitting chip 210 to ultimately emit white light. The fluorescent adhesive layer 220 with this structure not only makes the light emission angle of the light source structure large, but also makes encapsulation easier. Furthermore, the side heat-conducting part 222 can play a role in heat conduction, transferring the heat generated above the light-emitting chip 210. Specifically, when the phosphor absorbs about 70% of the blue light, this light is quickly conducted downwards by the phosphor and can be quickly dissipated by the adhesive layer contact part 320. Compared with conventional CSP technology, the packaging structure of this embodiment achieves a surface temperature of only 110-120 degrees Celsius under stable light emission conditions, far below the 150-degree limit of conventional CSP, thereby improving the reliability of the LED chip and achieving stable and efficient heat dissipation.

[0041] like Figure 1 As shown, further, in this embodiment, the thickness of one side of the side heat-conducting portion 222 gradually increases along the direction from the end face cover portion 221 toward the circuit board 100. Specifically, the side heat-conducting portion 222 surrounding the outside of the light-emitting chip 210 is a hollow frustoconical structure. Since the light-emitting chip 210 is roughly square, the upper end of the side heat-conducting portion 222 is thinner than the lower end on one side of the light-emitting chip 210. This structure allows for a larger contact area between the lower end of the side heat-conducting portion 222 and the heat dissipation layer 300, resulting in higher thermal conductivity and improved heat dissipation.

[0042] The fluorescent structure in this embodiment has various forms, such as Figure 1 As shown, for example, the first structural form only uses the fluorescent adhesive layer 220 with the end face covering portion 221 and the side heat-conducting portion 222 described above. The light-emitting function and technical problem can be solved with only one layer of this fluorescent adhesive layer 220. For example... Figure 2As shown, to improve heat dissipation, this embodiment also proposes a second structural form: the fluorescent structure not only includes the aforementioned fluorescent adhesive layer 220, but also has an inner fluorescent layer 230 disposed inside the fluorescent adhesive layer 220, located between the end face cover portion 221 and the light-emitting chip 210. The thickness of the inner fluorescent layer 230 is thinner than the thickness of the end face cover portion 221, and the phosphor concentration in the inner fluorescent layer 230 is different from the phosphor concentration in the outer fluorescent adhesive layer 220. Since the inner fluorescent layer 230 is closer to the front side of the light-emitting chip 210 and mainly undertakes the function of light conversion, it can be made thinner, thereby facilitating heat dissipation and reducing the risk of cracking of the fluorescent structure. The thicker thickness of the end face cover portion 221 facilitates heat conduction, thereby improving the heat dissipation performance of the entire light source structure.

[0043] like Figure 2 As shown, the phosphor mass percentage of the phosphor in the phosphor adhesive layer 220 is lower than that in the inner phosphor layer 230. Specifically, the phosphor mass percentage in the inner phosphor layer 230 can be 50-90%, while that in the phosphor adhesive layer 220 is 0-40%. The thickness of the inner phosphor layer 230 can be ≤150μm, and the thickness of the end-face cover 221 is 150-1000μm. This results in a thinner inner phosphor layer 230 with higher density, similar in size to the light-emitting chip 210, which is beneficial for heat dissipation of the light-emitting chip 210 and improves the luminous efficiency of the LED chip. The phosphor concentration used in the outer phosphor adhesive layer 220 is lower, allowing the formed phosphor adhesive layer 220 to be semi-transparent or even transparent. The semi-transparent or transparent phosphor adhesive layer 220 facilitates accurate subsequent processes such as die bonding and electrode alignment on the previously formed inner phosphor layer 230, reducing process difficulty and thus lowering device fabrication costs.

[0044] like Figure 3 , Figure 4 As shown, in this embodiment, the outer extension 330 is further bent on the outer side of the optical lens layer 400. By adopting an outer-bent outer extension structure, the surface area of ​​the outer extension 330 can be increased, thereby increasing the contact area with external airflow and allowing the conducted heat to be carried away by the airflow in a timely manner, further improving heat dissipation efficiency.

[0045] like Figure 3 , Figure 4 As shown, the curved outer extension 330 further includes at least one arcuate segment 331, and a vent 332 is formed between the at least one arcuate segment 331 and the circuit board 100. This increases the air contact area on the upper surface of the arcuate segment 331, and also forms a vent 332 for air flow on the lower surface, thereby increasing the contact area on the lower surface as well. Heat dissipation occurs simultaneously on the upper and lower surfaces, thereby improving the overall heat dissipation efficiency.

[0046] The heat dissipation layer 300 can be configured in various ways. For example... Figure 3 As shown, one configuration of the heat dissipation layer 300 is as follows: the heat dissipation layer 300 is configured as an independent unit and matched with a single CSP light source 200, meaning that the heat dissipation layer 300 can be directly encapsulated together with the CSP light source 200 during the molding process. Therefore, when the CSP light source 200 is soldered onto the circuit board 100, the heat dissipation layer 300 and the CSP light source 200 are also directly fixed to the circuit board 100 as a whole. The outer extensions 330 of each heat dissipation layer 300 mounted on the circuit board 100 can be spaced apart, each dissipating heat for its corresponding CSP light source 200. This simplifies the overall backlight structure, requiring only an improvement to the light source structure. With the improved light source structure in mass production, this significantly improves the assembly efficiency and reduces the complexity of the backlight structure.

[0047] like Figure 4 As shown, another configuration of the heat dissipation layer 300 is as follows: the heat dissipation layer 300 is an integral heat sink structure. Multiple areas corresponding to the mounting positions of the CSP light sources 200 are provided on the integral heat dissipation layer 300. Before soldering the CSP light sources 200, the heat dissipation layer 300 is laid on the circuit board 100, and then each CSP light source 200 is soldered to the corresponding area. In this way, the outer extensions 330 of each area of ​​the heat dissipation layer 300 are connected to form a whole, allowing multiple CSP light sources 200 to be distributed on the integral heat dissipation layer 300. This reduces the difficulty of customer assembly and simplifies the process.

[0048] like Figure 1 As shown, further, the heat dissipation layer 300 in this embodiment can be a thermally conductive insulating sheet. The thermally conductive insulating sheet is mainly formed from insulating and thermally conductive materials. Combining insulation and thermal conductivity, it is widely used in the electronics and electrical appliance industries. Examples include thermally conductive silicone insulating sheets, polyimide film thermally conductive insulating sheets, or thermally conductive PA6. Thermally conductive silicone insulating sheets are high-performance elastomeric insulating materials with a special film as the substrate, possessing excellent cut resistance and excellent thermal conductivity. Polyimide film thermally conductive insulating sheets use a high-performance polyimide film as the substrate, possessing both thermal conductivity and high voltage-resistant insulation properties. Thermally conductive PA6 has a high thermal conductivity and high-temperature resistance, making it suitable for electronic and electrical components. Using the above-mentioned materials, the thermally conductive insulating sheet can ensure the stable operation and long lifespan of the backlight structure.

[0049] In summary, this invention proposes a highly efficient heat dissipation CSP backlight structure. Compared to existing backlight structures, it features a simplified heat dissipation structure, requires less space, and effectively dissipates heat, improving the heat dissipation efficiency of the CSP light source and ensuring continuous and stable luminescence under high luminous performance. Due to its simple structure, it also reduces assembly difficulty for clients and simplifies manufacturing processes.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-efficiency heat dissipation CSP backlight structure, characterized in that, include: A circuit board having a first surface; Multiple CSP light sources are disposed on the first surface, and each CSP light source is covered with an optical lens layer on its outer side; A heat dissipation layer is disposed between the circuit board and the CSP light source; The heat dissipation layer is in contact with the CSP light source and extends to the outside of the optical lens layer to dissipate heat from the CSP light source.

2. The high-efficiency heat dissipation CSP backlight structure as described in claim 1, characterized in that, The CSP light source includes: a light-emitting chip, and a phosphor layer covering the light-emitting chip; The heat dissipation layer includes: a chip contact portion, which is located between the light-emitting chip and the circuit board. The chip contact portion has a clearance hole, and the electrode of the light-emitting chip passes through the clearance hole and is fixedly connected to the circuit board. The adhesive layer contact portion is connected to the outside of the chip contact portion and is in contact with the fluorescent adhesive layer; An outer extension is connected to the adhesive layer contact portion and located on the outside of the optical lens layer.

3. The high-efficiency heat dissipation CSP backlight structure as described in claim 2, characterized in that, The fluorescent adhesive layer includes: an end face covering portion, the end face covering portion covering the front side of the light-emitting chip; A side heat-conducting portion surrounds the outer edge of the end face cover and extends toward the circuit substrate. The side heat-conducting portion is located outside the light-emitting chip and abuts against the adhesive layer contact portion.

4. The high-efficiency heat dissipation CSP backlight structure as described in claim 3, characterized in that, The thickness of the side heat-conducting portion gradually increases along the direction of the end face covering portion toward the circuit board.

5. The high-efficiency heat dissipation CSP backlight structure as described in claim 3, characterized in that, An inner fluorescent layer is disposed inside the fluorescent adhesive layer, and the inner fluorescent layer is located between the end face cover and the light-emitting chip.

6. The high-efficiency heat dissipation CSP backlight structure as described in claim 5, characterized in that, The phosphor content of the fluorescent adhesive layer is less than that of the phosphor content of the inner fluorescent layer.

7. The high-efficiency heat dissipation CSP backlight structure as described in claim 2, characterized in that, The outer extension is bent and located on the outside of the optical lens layer.

8. The high-efficiency heat dissipation CSP backlight structure as described in claim 7, characterized in that, The curved outer extension includes at least one arcuate segment, and at least one of the arcuate segments forms a vent hole between itself and the circuit board.

9. The high-efficiency heat dissipation CSP backlight structure as described in claim 2, characterized in that, The outer extensions of the heat dissipation layer are spaced apart to form independent units, and are respectively matched with multiple CSP light sources; Alternatively, the outer extensions of the heat dissipation layer are connected to form a whole, and multiple CSP light sources are distributed on the whole heat dissipation layer.

10. The high-efficiency heat dissipation CSP backlight structure as described in any one of claims 1-9, characterized in that, The heat dissipation layer is a thermally conductive insulating sheet.

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