CSP light source and backlight strip

Abstract

The invention discloses a CSP light source and a backlight strip, and belongs to the technical field of backlight sources, the CSP light source comprises a ceramic substrate and an LED chip fixed on a first surface of the ceramic substrate; a white wall colloid is attached to the first surface of the ceramic substrate around the LED chip; the white wall colloid extends towards the light emitting direction of the LED chip to form a light scattering part; a fluorescent layer and a diffusion layer used for evenly diffusing light are installed on the light-emitting face of the LED chip in a stacked mode. The edges of the fluorescent layer and the diffusion layer abut against the white wall colloid. After the integrated ceramic substrate and the CSP packaged LED backlight light source are directly adopted in the backlight light bar, the backlight light bar is stable and free of mechanical stress risks, the requirements for high reliability and high performance are met, and the service life of the backlight module is prolonged. Meanwhile, the ceramic substrate can bear a high-power LED light source, high-power driving can be achieved, the requirement can be met by using a small number of LED light source particles, and the material cost of the backlight module and the power consumption of devices are saved.

Description

Technical Field

[0001] The present invention relates to the technical field of backlights, and particularly to a CSP light source and a backlight strip. Background Art

[0002] With the continuous progress of technology, as an important device for home entertainment, the picture quality and performance of televisions have been continuously improved. Among them, the backlight strip light source (referred to as the backlight) is one of the key factors affecting the picture quality of televisions, and its technological development has attracted much attention.

[0003] Currently, most backlights use bracket-type plastics: light sources made of EMC (engineering plastic) and SMC (molded plastic). However, due to the characteristics of the material itself, it is impossible to manufacture medium and high-power products. On some large-size products, the required brightness can only be achieved by increasing the number of lamp beads. This results in poor heat dissipation performance, poor airtightness and vulcanization effect, and poor reliability, reducing the service life of the product.

[0004] Although CSP (Chip Scale Package) light sources have advantages in certain applications, in the application of backlight strip light sources, problems such as fragile structure, insufficient heat dissipation performance, and poor light output uniformity of CSP light sources make it difficult for CSP light sources to be widely used in backlight strips. Summary of the Invention

[0005] The purpose of the present invention is to provide a CSP light source and a backlight strip, which can improve problems such as fragile structure, insufficient heat dissipation performance, and poor light output uniformity existing in CSP light sources. When used as a backlight in a backlight strip, it can improve the display effect of the backlight strip.

[0006] The technical solutions to achieve the above purpose include the following:

[0007] A CSP light source, comprising a ceramic substrate and an LED chip fixed on the first surface of the ceramic substrate;

[0008] Around the LED chip, a white wall colloid is also attached to the first surface of the ceramic substrate;

[0009] The white wall colloid extends in the light-emitting direction of the LED chip to form a light-scattering portion; a fluorescent layer and a diffusion layer for uniformly diffusing light are stacked on the light-emitting surface of the LED chip; the edges of the fluorescent layer and the diffusion layer abut against the white wall colloid.

[0010] In one embodiment, the end of the white wall colloid facing the light-emitting direction of the LED chip is recessed inward in an arc shape to form the light-scattering portion.

[0011] In one embodiment, the radian of the light scattering portion is 15 degrees to 25 degrees.

[0012] In one embodiment, the ceramic substrate further has a second surface opposite to the first surface. Conductive circuit layers are provided on both the first surface and the second surface. The conductive circuit layer includes pads arranged in pairs, and the LED chip is fixed on the conductive circuit layer of the first surface.

[0013] In one embodiment, there is a gap between the pads arranged in pairs, and the white wall colloid is filled in the gap on the first surface.

[0014] In one embodiment, the cross-sectional area of the fluorescent layer and the diffusion layer is larger than the cross-sectional area of the LED chip. The white wall colloid includes a first colloid and a second colloid. The first colloid is attached to the LED chip and the top end of the first colloid is flush with the top end of the LED chip. The fluorescent layer and the diffusion layer are in contact with the second colloid, and the first colloid forms a support for the fluorescent layer and the diffusion layer.

[0015] In one embodiment, the material of the fluorescent layer includes one or more of yttrium aluminum garnet, nitride, silicate, fluoride; and / or, the material of the white wall colloid includes methyl-based silicone rubber or phenyl-based silicone rubber and titanium dioxide.

[0016] The present invention also provides a backlight strip, which includes a substrate and a plurality of CSP light sources according to any one of the above. The plurality of CSP light sources are array-mounted on the substrate, and a connector is provided on the substrate.

[0017] In one embodiment, it further includes a plurality of secondary optical components mounted on the substrate. The secondary optical components correspond to the CSP light sources one by one, and the CSP light source is located in a cavity formed by enclosing the secondary optical component and the substrate.

[0018] In one embodiment, the substrate is an aluminum substrate, and the thickness of the substrate is 0.8 mm - 1.2 mm; and / or, the material of the secondary optical component includes one or more of silicone rubber, optical grade polymethyl methacrylate, and PC polycarbonate.

[0019] The technical solution provided by the present invention has the following advantages and effects:

[0020] By integrating the ceramic substrate, the white wall colloid reinforces the LED chip and extends to form a light scattering portion. The CSP light source emits light evenly and can better resist external impact and pressure. It solves the problems such as the inability of the CSP light source to split light and the fragility of the external structure, and improves the heat dissipation performance. It enables the CSP light source to be conveniently and reliably applied to the backlight strip.

[0021] After directly adopting an integrated ceramic substrate and a CSP-packaged LED backlight source in the backlight strip, it is stable and free from the risk of mechanical stress, meeting the requirements of high reliability and high performance, and increasing the lifespan of the backlight module. At the same time, the ceramic substrate can carry a high-power LED light source, can be driven at high power, and the requirements can be achieved by using a small number of LED light source particles, saving the material cost of the backlight module and the power consumption of the device. Description of the Drawings

[0022] The drawings here show specific examples of the technical solutions of the present invention and form part of the specification together with the specific implementation manners, and are used to explain the technical solutions, principles and effects of the present invention.

[0023] Unless otherwise specified or defined, in different drawings, the same reference numerals represent the same or similar technical features, and for the same or similar technical features, different reference numerals may also be used to represent them.

[0024] Figure 1 Schematic diagram after CSP light source packaging for an embodiment of the present invention;

[0025] Figure 2 is Figure 1 Exploded view of the CSP light source of the embodiment;

[0026] Figure 3 is Figure 1 Schematic diagram of the light effect of the CSP light source of the embodiment;

[0027] Figure 4 Top view of the backlight strip for an embodiment of the present invention;

[0028] Figure 5 is Figure 4 Front view of the backlight strip of the embodiment.

[0029] Description of the Reference Numerals:

[0030] 100, CSP light source; 110, ceramic substrate; 111, first surface; 112, second surface; 120, conductive circuit layer; 121, pad; 122, gap; 130, LED chip; 131, light-emitting surface; 140, white wall colloid; 141, light-scattering part; 142, first colloid; 143, second colloid; 150, fluorescent layer; 160, diffusion layer,

[0031] 200, backlight strip; 210, substrate; 211, connector; 220, secondary optical component. Detailed Description of the Invention

[0032] For the convenience of understanding the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings of the specification.

[0033] Unless otherwise specified or defined, the "first, second..." used herein is only for distinguishing names and does not represent a specific quantity or order.

[0034] Unless otherwise specified or defined, the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0035] It should be noted that when an element is considered to be "fixed to" another element, it can be directly fixed to the other element or there can be an intermediate element; when an element is considered to be "connected to" another element, it can be directly connected to the other element or there can be an intermediate element at the same time; when an element is considered to be "mounted on" another element, it can be directly mounted on the other element or there can be an intermediate element at the same time. When an element is considered to be "provided in" another element, it can be directly provided in the other element or there can be an intermediate element at the same time.

[0036] Although the CSP light source package has a small volume, is suitable for application scenarios with limited space, has a high light output efficiency, can provide brighter illumination, and reduces energy consumption at the same time. It overcomes the problems of poor airtightness and poor vulcanization effect of the bracket-type LED light source and has advantages in some applications, but there are still the following problems in the application of the backlight strip light source: due to the small package volume of the CSP light source, there is usually no protective shell like traditional lamp beads, lacking sufficient mechanical protection, the structure is fragile, and it is easy to be affected by stress during chip mounting or use, resulting in damage; the heat dissipation design of the CSP light source is relatively weak, especially in the application of the backlight strip, it may affect the light effect and life due to overheating; the light distribution of the CSP light source is small and the light output uniformity is poor, which may lead to uneven light output of the backlight strip and affect the display effect.

[0037] In order to make the CSP light source better applied to the backlight strip, the present invention integrates a ceramic structure on the CSP light source and redesigns and reinforces the housing of the CSP light source, so that it can better resist external impacts and pressures, solve the problem of the fragile external structure of the CSP light source, and improve the heat dissipation performance of the CSP light source; and designs a structure for scattering light to solve the problem that the CSP light source cannot split light.

[0038] Such as Figure 1 and Figure 2As shown in the figure, this embodiment provides a CSP light source 100, which includes a ceramic substrate 110. The ceramic substrate 110 has opposite first and second surfaces 111 and 112, and conductive circuit layers 120 are provided on both the first surface 111 and the second surface 112. The conductive circuit layer 120 on the first surface 111 is arranged corresponding to the conductive circuit layer 120 on the second surface 112. Specifically, the conductive circuit layer 120 is composed of paired pads 121, and there is a gap 122 between the two pads 121. The two pads 121 are respectively used as connection terminals for the positive and negative electrodes. There are two vias (not shown in the figure) inside the ceramic substrate 110, and the conduction connection between the pads 121 on the first surface 111 and the corresponding pads 121 on the second surface 112 is realized through the vias. The LED chip 130 is fixed on the first surface 111 of the ceramic substrate 110, for example: welded to the pads 121 on the first surface 111 of the ceramic substrate 110 through eutectic soldering and dot tinning processes. The LED chip 130 can be selected with different sizes according to the actual power conditions. The pads 121 on the second surface 112 of the ceramic substrate 110 are used to weld the CSP light source 100 to an external substrate.

[0039] Since the power of current LED chips is relatively high and a certain amount of energy is released in the form of heat, and overheating of the backlight will affect the performance of circuit components, reduce the light-emitting efficiency of the backlight, and cause uneven backlighting. By integrating a ceramic substrate in the CSP light source, the ceramic substrate has a high thermal conductivity and can effectively dissipate the heat generated by the light source, reducing the working temperature of the light source, thereby improving the stability and service life of the backlight; moreover, the ceramic substrate has a high mechanical strength, can provide better structural support, and enhance the durability and shock resistance of the backlight.

[0040] In this embodiment, the LED chip 130 is an LED blue chip, but it is not limited to this type of chip. The materials commonly used for the LED chip 130 (such as silicon, resin, etc.) will become fragile under high temperature or stress. During the chip mounting process, the CSP light source needs to withstand a certain amount of mechanical stress, resulting in cracks or fractures easily occurring during the chip mounting process. To insulate and protect the LED chip 130, a white wall colloid 140 is also bonded around the LED chip 130 on the first surface 111 of the ceramic substrate 110. Considering that there is a gap 122 between the two pads 121 on the first surface 111 of the ceramic substrate 110, in order to improve the insulation effect, the white wall colloid 140 is also filled in the gap 122. The white wall colloid 140 filled in the gap 122 can also support the LED chip 130. The material of the white wall colloid 140 is not limited, and its main components are a combination of methyl-based silicone rubber or phenyl-based silicone rubber and titanium dioxide. The white wall colloid 140 can perform optical diffuse reflection, improve the light output efficiency of the LED chip 130, reduce light loss, thereby improving the overall light efficiency of the backlight source, and can also reinforce the LED chip 130, providing a certain degree of protection for the LED chip 130 to prevent the influence of the external environment on the LED chip 130, such as moisture and dust.

[0041] Reference Figure 1 , the light-emitting direction of the LED chip 130 is upward, so the upper surface of the LED chip 130 is also called the light-emitting surface 131. A fluorescent layer 150 and a diffusion layer 160 are stacked and installed on the light-emitting surface 131 of the LED chip 130. The diffusion layer 160 is above the fluorescent layer 150, and the edges of the fluorescent layer 150 and the diffusion layer 160 abut against the white wall colloid 140. The fluorescent layer 150 is used to excite the light emitted by the LED chip 130 to form various colors of light required and emit it upward. The fluorescent layer 150 is configured by mixing phosphor and silicone in a certain proportion. Among them, the ratio of phosphor to silicone can be configured according to actual light-emitting requirements. The phosphor is one or a combination of phosphors in systems such as yttrium aluminum garnet (YAG), nitride, silicate, fluoride, etc., so as to form different optical colors. The diffusion layer 160 can evenly disperse light, reduce light spots and shadows, ensure the uniformity of light illumination, and improve the distribution and uniformity of light. The diffusion layer 160 is made of materials such as titanium dioxide, silicate powder, polystyrene (PS) or polyethylene (PE) microspheres and is bonded with epoxy resin or polyurethane.

[0042] In order to further improve the light uniformity when the CSP light source 100 is applied to the backlight bar, the white wall colloid 140 extends in the light-emitting direction of the LED chip 130 to form a light scattering portion 141. Specifically, in this embodiment, the end of the white wall colloid 140 facing the light-emitting direction of the LED chip 130 is recessed inward in an arc shape, that is, the white wall colloid 140 has an inner arc surface, and this inner arc surface forms the light scattering portion 141. And preferably, the radian of the arc-shaped recess is 15 degrees to 25 degrees, and at this time, the effect of light diffusion is better. As Figure 3 shown, the light scattering portion 141 can cause a diffuse reflection effect on the light, improving the light uniformity. It should be noted that the shape of the light scattering portion is not limited to the inner arc surface of this embodiment.

[0043] Preferably, the cross-sectional area of the fluorescent layer 150 and the diffusion layer 160 is larger than the cross-sectional area of the LED chip 130, that is, the fluorescent layer 150 and the diffusion layer 160 cover the LED chip 130, which can improve the light uniformity. Correspondingly, the white wall colloid 140 includes two parts: the first colloid 142 and the second colloid 143. The first colloid 142 is attached to the periphery of the LED chip 130 and the top end of the first colloid 142 is flush with the top end of the LED chip 130. The second colloid 143 is located above the first colloid 142, and the second colloid 143 is attached to the edges of the fluorescent layer 150 and the diffusion layer 160. Part of the fluorescent layer 150 and the diffusion layer 160 is supported on the first colloid 142, that is, the first colloid 142 forms a support for the fluorescent layer 150 and the diffusion layer 160 to reduce the pressure on the LED chip 130.

[0044] In summary, by redesigning and strengthening the housing of the light source, the CSP light source with an integrated ceramic structure not only solves the problems of poor airtightness and poor vulcanization effect of the bracket-type LED light source, and can better resist external impacts and pressures. Moreover, it also solves the problems such as the inability to split light and the fragile external structure of the CSP light source. And, through the design structure of the self-made ceramic light source and the characteristics of the material itself, the thermal resistance of the light source is reduced, and the heat dissipation performance is improved; the overall module heat dissipation performance can be improved, thereby improving the service life of the product. The CSP light source can be conveniently and reliably applied to the backlight bar.

[0045] When the CSP light source with an integrated ceramic structure is integrated as the core into the backlight bar module, high-power LED chips can be used, significantly reducing the number of light sources used, reducing costs, improving the display effect of the backlight bar, and meeting the requirements of energy conservation and environmental protection.

[0046] As Figure 4 and Figure 5As shown in the figure, this embodiment also provides a backlight strip 200, which includes a substrate 210 and a plurality of the above-mentioned CSP light sources 100. The plurality of CSP light sources 100 are array-mounted on the substrate 210. For example, they are fixed on the substrate 210 after solder paste printing and reflow soldering. The size of the CSP light source 100 can be cut into different sizes according to the actual project situation, such as 16*16mm, 20*20mm, 25*25mm, 30*30mm, etc. A connector 211 is also provided on the substrate 210 to serve as the input and output terminals of the power supply. The position of the connector 211 can be in specifications such as 2-pin, 3-pin or multi-pin according to the actual circuit layout. Parameters such as the shape, thickness, material, and process of the substrate 210 can be adjusted according to the specific power state and optical conditions.

[0047] In this embodiment, a secondary optical component 220 is provided corresponding to each CSP light source 100 on the backlight strip 200. The material of the secondary optical component 220 can be one or more of silicone, optical grade PMMA (polymethyl methacrylate), and PC (polycarbonate). The appearance and size can be in various styles. It is fixed above the CSP light source 100 and on the substrate 210 through curing modes such as UV or lens glue. The secondary optical component 220 and the substrate 210 enclose a cavity, and this cavity forms a wrapping for the CSP light source 100. The secondary optical design is completed through a lens made of materials such as PMMA, which can not only protect the CSP light source 100 but also improve the light effect.

[0048] Since the thermal resistance coefficient of the CSP light source with an integrated ceramic substrate can reach 6 °C / W, while the thermal resistance coefficient of a conventional bracket-type light source is approximately 10 °C / W. Therefore, the substrate 210 can use a more lightweight and practical aluminum substrate with a thickness of 0.8 mm - 1.0 mm (its internal material combination is an ink layer, a copper foil layer, an insulating layer, and an aluminum layer). In this embodiment, the thickness of the substrate 210 is 0.8 mm. Of course, the substrate 210 can be divided into different sizes according to the actual usage situation, and it can also be in the shape of a long strip or a square, etc. It can also be a copper substrate, an FR4 board, a BT board, etc. according to the actual product power.

[0049] In this embodiment, an integrated ceramic substrate and a CSP-packaged LED backlight source are directly adopted in the backlight strip, which greatly improves the heat dissipation efficiency, insulation, and airtightness of the backlight source. At the same time, it has stability and no mechanical stress risk, meets the requirements of high reliability and high performance, and increases the lifespan of the backlight module. At the same time, the ceramic substrate can carry a high-power LED light source, can be driven at high power, and can meet the requirements by using a small number of LED light source particles, saving the material cost of the backlight module and the power consumption of the device.

[0050] When referring to the drawings, the new features that appear are described; in order to avoid the description being not concise enough due to repeated reference to the drawings, the features that have been described will not be cited one by one in the drawings when the description is clear.

[0051] The purpose of the above embodiments is to exemplarily reproduce and deduce the technical solutions of the present invention, and to completely describe the technical solutions, purposes and effects of the present invention. The purpose is to make the public understand the disclosed content of the present invention more thoroughly and comprehensively, and it does not limit the protection scope of the present invention.

[0052] The above embodiments are not an exhaustive list of the present invention. In addition, there may be multiple other embodiments not listed. Any substitution and improvement made on the basis of not violating the concept of the present invention fall within the protection scope of the present invention.

Claims

1. CSP light source, characterized in that include: A ceramic substrate and an LED chip fixed on a first surface of the ceramic substrate; Surrounding the LED chip, a white wall colloid is also attached to the first surface of the ceramic substrate; The white wall colloid extends toward the light emitting direction of the LED chip to form a light scattering portion; a fluorescent layer and a diffusion layer for evenly diffusing light are stacked and installed on the light emitting surface of the LED chip; the edges of the fluorescent layer and the diffusion layer abut against the white wall colloid.

2. The CSP light source according to claim 1, characterized in that: The end of the white wall colloid facing the light emitting direction of the LED chip is concave inwardly in an arc shape to form the light scattering part.

3. The CSP light source according to claim 2, characterized in that: The curvature of the light scattering portion is 15 degrees to 25 degrees.

4. The CSP light source according to claim 1, characterized in that: The ceramic substrate is also provided with a second surface opposite to the first surface. Both the first surface and the second surface are provided with a conductive circuit layer. The conductive circuit layer includes pads arranged in pairs. The LED chip is fixed on the conductive circuit layer of the first surface.

5. The CSP light source according to claim 4, characterized in that: There is a gap between the pads arranged in pairs, and the gap on the first surface is filled with the white wall glue.

6. The CSP light source according to any one of claims 1 to 5, characterized in that: The cross-sectional areas of the fluorescent layer and the diffusion layer are larger than the cross-sectional areas of the LED chip. The white wall colloid includes a first colloid and a second colloid. The first colloid is bonded to the LED chip and the top of the first colloid is flush with the top of the LED chip. The fluorescent layer and the diffusion layer are in contact with the second colloid. The first colloid forms a support for the fluorescent layer and the diffusion layer.

7. The CSP light source according to any one of claims 1 to 5, characterized in that: The material of the fluorescent layer includes one or more of yttrium aluminum garnet, nitride, silicate, and fluoride; and / or the material of the white wall colloid includes methyl organic silica gel or phenyl organic silica gel and titanium dioxide.

8. A backlight strip, characterized in that: include: A substrate and a plurality of CSP light sources as claimed in any one of claims 1 to 7, wherein the plurality of CSP light source arrays are mounted on the substrate, and a connector is provided on the substrate.

9. The backlight strip according to claim 8, wherein: It also includes a plurality of secondary optical components mounted on the substrate, wherein the secondary optical components correspond to the CSP light sources one by one, and the CSP light sources are located in a cavity formed by the secondary optical components and the substrate.

10. The backlight strip according to claim 8, wherein: The substrate is an aluminum substrate, and the thickness of the substrate is 0.8 mm-1.0 mm; and / or the material of the secondary optical component includes one or more of silica gel, optical grade polymethyl methacrylate and PC polycarbonate.

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