LED packaging structure, packaging method and backlight module

Abstract

The invention relates to the technical field of LED packaging, and discloses an LED packaging structure, a packaging method and a backlight module, the LED packaging structure comprises an LED chip and a packaging colloid arranged on the surface of the LED chip; the packaging colloid comprises a first packaging colloid, a second packaging colloid and a white glue layer; the upper surface of the LED chip is provided with a box dam with a cavity, and the first packaging colloid is arranged in the cavity of the box dam and is flush with the box dam; the second packaging colloid wraps the surface of the LED chip and is isolated from the first packaging colloid through the box dam, the second packaging colloid is higher than the box dam, the first packaging colloid, the box dam and the second packaging colloid form a pit with an inclined plane, and the white glue layer is arranged in the pit. By implementing the backlight module, the light emitting angle of the LED chip can be effectively expanded, the light emitting uniformity of the LED chip can be improved, the visual effect of the backlight module can be improved, the use number of the LED chip can be reduced, and the thickness can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and in particular to an LED packaging structure, a packaging method and a backlight module. Background Art

[0002] The backlight module is usually composed of a substrate, LED lamp beads, lenses, and diffusers. When a conventional LED package structure is used as a display backlight source, it is necessary to use the refraction of the lens to increase its light-emitting angle to ensure that the backlight module mixes light evenly. The use of lenses can increase the distance between LED chips, reduce the number of LED chips used, and reduce the cost of the entire display. At the same time, it can also reduce the mixing distance and the thickness of the entire display, making the display thinner and lighter.

[0003] The conventional LED packaging structure is mainly composed of a bracket 25, an LED chip 1, wires, and a packaging colloid 2. Figure 1 As shown in FIG. 1 , it has good directivity, with strong central light and weak surrounding light. Its light emitting angle is small, usually about 100°~120°. A conventional LED backlight module is usually composed of a substrate 7, an LED chip 1, a lens, and a diffuser 8. Figure 2 As shown, when conventional LED chips are used as display backlight sources, the smaller the light-emitting angle of the LED chip, the stronger the light intensity directly above the LED chip, and the weaker the light intensity at the edge, resulting in alternating light and dark and uneven light mixing. At this time, the spacing between the LED chips needs to be reduced so that the light-emitting edges of two adjacent LED chips overlap to achieve the same light intensity as directly above the LED chip. When the spacing between the LED chips is reduced, more LED chips are required, increasing the cost; or, without reducing the spacing between the LED chips, it is necessary to increase the distance between the LED chip and the diffuser, that is, to increase the light mixing distance, so that the light emitted from the LED edge overlaps at a farther distance. At this time, the backlight module will be thicker, which is not conducive to the application of thin and light displays. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an LED packaging structure, a packaging method and a backlight module, which effectively expand the light output angle of the LED chip and improve the light output uniformity of the LED chip.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides an LED packaging structure, comprising: an LED chip and a packaging colloid arranged on the surface of the LED chip; The encapsulating colloid comprises a first encapsulating colloid, a second encapsulating colloid and a white glue layer; A dam with a cavity is provided on the upper surface of the LED chip, and the first encapsulation colloid is provided in the cavity of the dam and is flush with the dam; the second encapsulation colloid wraps the surface of the LED chip and is isolated from the first encapsulation colloid by the dam, the height of the second encapsulation colloid is higher than the height of the dam, the first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface, and the white glue layer is provided in the pit.

[0006] As an improvement of the above solution, in the pit, the angle formed by the dam and the second encapsulation colloid is 140°-150°.

[0007] As an improvement of the above solution, the ratio of the thickness of the white glue layer to the thickness of the first encapsulating colloid is 5:1-6:1.

[0008] As an improvement of the above solution, the height of the dam is 1 / 3 to 2 / 3 of the thickness of the LED chip; The width of the cavity of the dam is 1 / 3 to 2 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 to 1 / 3 of the width of the LED chip.

[0009] As an improvement of the above solution, the material of the first encapsulating colloid is the first silicone, the material of the second encapsulating colloid is the second silicone, the material of the dam is the third silicone, the refractive index of the first silicone is n1, the refractive index of the second silicone is n2, the refractive index of the third silicone is n3, and the refractive index of the white glue in the white glue layer is n4, satisfying the following formula: n3>n1>n2>n4.

[0010] The second aspect of the present invention further provides a packaging method of the LED packaging structure, comprising: (1) Fixing LED chips on the carrier board so that the LED chips are arranged in an array; (2) forming a dam having a cavity on the upper surface of each of the LED chips; (3) forming a first encapsulation colloid and a second encapsulation colloid on the surface of each of the LED chips, wherein the first encapsulation colloid and the second encapsulation colloid are separated by the dam, and the first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface; (4) forming a white glue layer in the pit; (5) Cutting is performed according to the preset row and column spacing and separated from the carrier to obtain a single LED packaging structure.

[0011] As an improvement of the above solution, step (3) includes: (31) In the area outside the dam, a second encapsulating colloid is formed by scribing to wrap the LED chip and have a height higher than the dam, so that the second encapsulating colloid forms an inclined surface and is connected to the dam, and the inclined surface serves as the inclined surface of the pit; (32) A first encapsulating colloid is formed in the cavity of the dam, and the first encapsulating colloid is flush with the dam to form a bottom surface of the pit.

[0012] As an improvement of the above solution, the dam with the cavity is formed by heating and curing, the heating and curing temperature is 100° C. to 150° C., and the heating and curing time is 30 min to 60 min. The encapsulation colloid is formed by heating and curing, the heating and curing temperature is 100° C. to 150° C., and the heating and curing time is 30 min to 60 min.

[0013] The third aspect of the present invention further provides an LED backlight module, comprising at least one LED packaging structure as described above.

[0014] As an improvement of the above solution, the LED backlight module further includes a substrate and a diffusion sheet, the LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0015] The implementation of the present invention has the following beneficial effects: (1) In the present invention, the LED chip is a flip chip, and a dam with a cavity is provided on the upper surface of the LED chip. The first encapsulation colloid is arranged in the cavity of the dam and is flush with the dam; the second encapsulation colloid wraps the surface of the LED chip and is isolated from the first encapsulation colloid by the dam. The height of the second encapsulation colloid is higher than the height of the dam. The first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface. The white glue layer is arranged in the pit, which effectively expands the light output angle of the LED chip and increases the light intensity at the edge, so that the light is mixed evenly, the phenomenon of uneven brightness is eliminated, and the light mixing distance is shortened, thereby reducing the number of LED chips used.

[0016] (2) The present invention provides an LED backlight module that avoids the use of lens components, has a short light mixing distance, and uses a small number of LED chips. Not only does it mix light evenly, improving the visual effect of the backlight module, but it also reduces the thickness of the LED backlight module, which is conducive to the preparation of a lighter and thinner LED backlight module. In addition, the implementation of the LED backlight module in this application also reduces costs in many aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : A schematic diagram of the structure of an LED packaging structure in the prior art; Figure 2 : A schematic diagram of the working of an LED backlight module in the prior art; Figure 3 : A schematic diagram of the structure of the LED packaging structure in the present invention; Figure 4 : A schematic diagram of the operation of step (1) in the present invention; Figure 5 : A top view of the LED packaging structure after step (1) of the present invention is completed; Figure 6 : A schematic diagram of the operation of step (2) in the present invention; Figure 7 : A top view of the LED packaging structure after step (2) of the present invention is completed; Figure 8 : A schematic diagram of the operation of step (31) in the present invention; Fig. 9 : A schematic diagram of the operation of step (32) in the present invention; Fig.10 : A schematic diagram of the operation of step (4) in the present invention; Fig.11 : A schematic diagram of the cutting process in step (5) of the present invention; Fig.12 : A schematic diagram of the structure of the LED packaging structure after the cutting is completed in step (5) of the present invention; Fig.13 : A schematic diagram of the working of the LED backlight module in the present invention; Fig.14 : A light intensity distribution curve diagram of the LED packaging structure provided in Example 1 of the present invention; Fig.15 : A light intensity distribution curve diagram of the LED packaging structure provided in Example 2 of the present invention; Fig.16 : A light intensity distribution curve diagram of the LED packaging structure provided in Example 3 of the present invention; Fig.17 : A light intensity distribution curve diagram of the LED packaging structure provided in Example 4 of the present invention; Fig.18 : Light intensity distribution curve of the LED packaging structure provided by the control group of the present invention; Fig.19 : A light mixing effect diagram of the LED backlight module provided in Example 3 of the present invention; Fig. 20 : A light mixing effect diagram of the LED backlight module provided by the control group in the present invention.

[0018] Figure numerals: 1-LED chip; 2-packaging colloid; 21-first packaging colloid; 22-second packaging colloid; 23-white glue layer; 24-pit; 25-bracket; 3-dam; 4-carrier; 5-adhesive layer; 6-cutting line; 7-substrate; 8-diffuser. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail with specific embodiments below.

[0020] In order to solve the above problems, the present invention provides a first aspect of an LED packaging structure, see Figure 3 , comprising: an LED chip 1 and an encapsulation colloid 2 arranged on the surface of the LED chip 1, wherein the LED chip 1 is a flip chip. The encapsulation colloid 2 can protect the LED chip 1 from moisture, dust, chemicals, external forces, etc. in the external environment, thereby ensuring the reliability and service life of the LED chip 1.

[0021] The encapsulation colloid 2 includes a first encapsulation colloid 21, a second encapsulation colloid 22 and a white glue layer 23. The upper surface of the LED chip 1 is provided with a dam 3 having a cavity. The first encapsulation colloid 21 is arranged in the cavity of the dam 3 and is flush with the dam 3. The second encapsulation colloid 22 wraps the surface of the LED chip 1 and is isolated from the first encapsulation colloid 21 by the dam 3. The height of the second encapsulation colloid 22 is higher than the height of the dam 3. The first encapsulation colloid 21, the dam 3 and the second encapsulation colloid 22 form a pit 24 with an inclined surface, and the white glue layer 23 is arranged in the pit 24.

[0022] In the present invention, the dam 3 can be used as a blocking ring, which is convenient for setting the first encapsulation colloid 21 and the second encapsulation colloid 22 on the upper surface and the side surface of the LED chip 1, and then it is easy to form a pit 24 with a slope. A white glue layer 23 is formed in the pit 24, so that the light emitted by the LED chip 1 can be reflected by the white glue layer 23 and emitted to the surroundings, thereby expanding the light emission angle of the LED chip 1, and at the same time increasing the light intensity at the edge, making the light mixed evenly, and also increasing the distance between adjacent LED chips 1, thereby reducing the number of LED chips 1 set.

[0023] Preferably, in the pit 24, the angle θ formed by the dam 3 and the second encapsulation colloid 22 is 140°~150°, which increases the contact area between the white glue layer 23 and the second encapsulation colloid 22, thereby improving the reflection ability of the LED light and further expanding the light output angle of the LED chip 1.

[0024] Furthermore, the ratio of the thickness H1 of the white glue layer 23 to the thickness H2 of the first encapsulation colloid 21 is 5:1~6:1. The white glue layer 23 of appropriate thickness can cause constructive interference between the reflected light and enhance the reflection effect. Then, under the reflection effect of the white glue layer 23, the luminous intensity at the edge of the LED chip 1 can be increased.

[0025] Furthermore, the height H3 of the dam 3 is 1 / 3 to 2 / 3 of the thickness H4 of the LED chip 1; the width W1 of the dam 3 is 1 / 6 to 1 / 3 of the width W2 of the LED chip 1, and the width W3 of the cavity of the dam 3 is 1 / 3 to 2 / 3 of the width W2 of the LED chip 1, so that an angle with a suitable inclination angle is formed between the second encapsulation colloid 22 and the dam 3, further controlling the path of the light emitted by the LED chip 1, reducing the total reflection occurring in the LED chip 1, improving the light emission efficiency, and increasing the light emission angle of the LED chip 1 from the conventional 120° to about 170°. It can be understood that the shape of the dam 3 can be circular, rectangular, rounded rectangular, etc., and the second encapsulation colloid 22 can be arranged only on the side surface of the LED chip 1, or can be arranged on the side surface and part of the upper surface of the LED chip 1, depending on the width W1 of the dam 3, the width W3 of the cavity and the shape of the dam. The width W1 of the dam 3 and the width W3 of the cavity can be appropriately adjusted according to specific needs.

[0026] It can be understood that the materials of the first encapsulation colloid 21, the second encapsulation colloid 22, and the dam 3 are preferably silicone with high light transmittance, which has strong adhesion to each other, enhances the air tightness of the LED package chip, and reduces the penetration path of impurities such as air into the LED chip 1. Exemplarily, the silicone is selected from transparent silicone and fluorescent glue. The transparent silicone has a high refractive index, which can reduce the loss of photons at the interface between the LED chip 1 and the air, and improve the light extraction efficiency; the fluorescent glue is silicone with fluorescent powder dispersed in it, and the fluorescent powder is evenly distributed in the silicone, which can change the color of the light and improve the uniformity of the light color.

[0027] Optionally, the material of the first encapsulation colloid 21 is a first silicone, which has certain adhesion and flexibility, so that the first encapsulation colloid 21 is tightly bonded to the upper surface of the LED chip 1 and the white glue layer 23, avoiding problems such as delamination and pores, and adapting to the thermal expansion and contraction and mechanical stress changes of the LED packaging structure during processing and use; more preferably, the bonding strength of the first silicone on the LED chip 1 is 3MPa~4MPa, and the bonding strength on the white glue layer 23 is 2.5MPa~3.5MPa. The material of the second encapsulation colloid 22 is a second silicone, which has certain hardness and elasticity, provides sufficient support for the LED chip 1, resists external impact force, prevents deformation, and also has certain viscosity, which is convenient for forming a smooth inclined surface; more preferably, the Shore A hardness of the second silicone is 40~60. The material of the dam 3 is a third silicone rubber, which has certain adhesion, hardness and thixotropy so as to be made into a blocking ring, and form a first encapsulating colloid 21 and a second encapsulating colloid 22 with preset requirements as a boundary, so as to better control the light propagation path; more preferably, the hardness of the third silicone rubber is less than that of the second silicone rubber.

[0028] Furthermore, the refractive index of the first silicone is n1, the refractive index of the second silicone is n2, the refractive index of the third silicone is n3, and the refractive index of the white glue in the white glue layer 23 is n4, satisfying the following formula: n3>n1>n2>n4. By limiting the refractive index of the first silicone, the second silicone, the third silicone and the white glue, the light emitting path of the LED chip 1 can be optimized, so that part of the emitted light enters the first packaging colloid 21 after being refracted at a larger angle, and then is reflected by the white glue layer 23 and emitted from the side, and also from the center of the first packaging colloid 21; part of the luminous light enters the dam 3 after being refracted at a smaller angle, and then is reflected by the white glue layer 23 and emitted from the side, and also from the center of the dam 3, thereby maintaining the light intensity in the middle area and enhancing the luminous intensity near the edge; the remaining part of the light enters the second packaging colloid 22 after being refracted at a larger angle, and then is reflected by the white glue layer 23 and emitted from the side, thereby improving the light emitting angle of the LED chip 1 as a whole and weakening the light intensity alternation in the middle and edge.

[0029] Accordingly, the present invention further provides a packaging method for the LED packaging structure, comprising: (1) Fixing the LED chips 1 on the carrier board 4 so that the LED chips 1 are arranged in an array; (2) forming a dam 3 having a cavity on the upper surface of each LED chip 1; (3) forming a first encapsulating colloid 21 and a second encapsulating colloid 22 on the surface of each LED chip 1, wherein the first encapsulating colloid 21 and the second encapsulating colloid 22 are separated by the dam 3, and the first encapsulating colloid 21, the dam 3 and the second encapsulating colloid 22 form a pit 24 with an inclined surface; (4) forming a white glue layer 23 in the pit 24; (5) Cutting is performed according to the preset row and column spacing and separated from the carrier board 4 to obtain a single LED packaging structure.

[0030] Each step is described in detail below. Figure 4~Figure 13 : Regarding (1), fixing the LED chips 1 on the carrier board 4 so that the LED chips 1 are arranged in an array, see Figure 4 and Figure 5 ; Specifically, an adhesive layer 5 for fixing the LED chip 1 is provided between the carrier 4 and the LED chip 1. Preferably, the carrier 4 is a steel plate, and the adhesive layer 5 is a double-sided tape, which has a good bonding effect on the LED chip 1 and the carrier 4, and is easy to peel off from the carrier 4 later, and the performance of the LED chip 1 will not be damaged during the peeling process. The substrate 7 is also easy to clean and can be reused many times. In some embodiments, the adhesive layer 5 is provided on the entire steel plate.

[0031] Regarding (2), forming a dam 3 having a cavity on the upper surface of each LED chip 1, see Figure 6 and Figure 7 ; Specifically, a dam 3 material, preferably a third silicone rubber, is disposed on the upper surface of each LED chip 1, and then heated and cured to obtain a dam 3 having a cavity. Further, the heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30min to 60min.

[0032] Furthermore, a height H3 of the dam 3 is 1 / 6 to 1 / 3 of a thickness H4 of the LED chip 1 , and a width W3 of a cavity of the dam 3 is 1 / 3 to 2 / 3 of a width W2 of the LED chip 1 .

[0033] Regarding (3), a first encapsulation colloid 21 and a second encapsulation colloid 22 are formed on the surface of each LED chip 1, the first encapsulation colloid 21 and the second encapsulation colloid 22 are separated by the dam 3, and the first encapsulation colloid 21, the dam 3 and the second encapsulation colloid 22 form a pit 24 with an inclined surface; Preferably, the step (3) comprises: (31) In the area outside the dam 3, a second encapsulating colloid 22 is formed by scribing to wrap the LED chip 1 and has a height higher than the dam 3, so that the second encapsulating colloid 22 forms an inclined surface and is connected to the dam 3. The inclined surface serves as the inclined surface of the pit 24. Figure 8 ; Specifically, the second encapsulating colloid 22 material, preferably the second silicone, is arranged on the carrier board 4 by scribing, so that it wraps the surface of the LED chip 1 outside the dam 3 and fills the gap between adjacent LED chips 1, and the height is higher than the height H3 of the dam 3, but the second silicone does not overflow the dam 3, so as to form the slope of the pit 24. According to the arrangement position and shape of the dam 3 on the upper surface of the LED chip 1, the second encapsulating colloid 22 may only cover the side surface of the LED chip 1, or may cover the side surface and part of the upper surface of the LED chip 1.

[0034] Further, a second silica gel is arranged on the LED chip 1 by scribing to form a semi-finished product of the second encapsulation colloid 22, and then, it is heated and cured to obtain a formed second encapsulation colloid 22, wherein the heating and curing temperature is 100°C to 150°C and the heating and curing time is 30min to 60min. In some embodiments, when forming the inclined surface, the X direction is scribed first, and then the Y direction is scribed; in other embodiments, when forming the inclined surface, the Y direction is scribed first, and then the X direction is scribed.

[0035] (32) A first encapsulating colloid 21 is formed in the cavity of the dam 3, and the first encapsulating colloid 21 is flush with the dam 3 to form the bottom surface of the pit 24, see Fig. 9 ; Specifically, the cavity of the dam 3 is filled with a first encapsulating colloid 21 material, preferably a first silicone gel, and the first encapsulating colloid 21 and the dam 3 can form the bottom surface of the pit 24, and the bottom surface is connected to the inclined surface formed by the second encapsulating colloid 22 to form an inwardly concave pit 24, and then, it is heated and cured to obtain a molded first encapsulating colloid 21, the heating and curing temperature is 100°C~150°C, and the heating and curing time is 30min~60min. It can be understood that the first encapsulating colloid 21 can also be slightly higher or slightly lower than the dam 3.

[0036] Regarding (4), forming a white glue layer 23 in the recess 24, please refer to Fig.10 ; Specifically, the recess 24 is filled with white glue, and then heated and cured to obtain a formed white glue layer 23, wherein the heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30min to 60min. The thickness H1 of the cured white glue layer 23 can be flush with the highest point of the second encapsulating colloid 22, or can be slightly higher or slightly lower than the highest point of the second encapsulating colloid 22.

[0037] Regarding (5), cutting according to the preset row and column spacing and separating from the carrier board 4 to obtain a single LED packaging structure, please refer to Fig.11 , Fig.12 and Figure 3 ; Specifically, the entire LED packaging structure is cut along the set cutting lines 6 to obtain a single LED packaging structure. The cutting lines 6 can be set according to the row and column spacing.

[0038] Correspondingly, the present invention also provides an LED backlight module, comprising the LED packaging structure.

[0039] Furthermore, the LED backlight module further comprises a substrate 7 and a diffuser 8, the LED packaging structure is fixed on the substrate 7, and the diffuser 8 is located above the LED packaging structure, see Fig.13 .

[0040] Specifically, the substrate 7 has a relative front and back surface, the LED packaging structure has a relative bottom and top surface, the LED packaging structure is fixed on the front surface of the substrate 7, the diffusion sheet 8 is located above the top surface of the LED packaging structure, and no lens is arranged between the LED packaging structure and the diffusion sheet 8.

[0041] Compared with the traditional LED backlight module, the LED packaging structure used in the present invention, on the one hand, expands the light-emitting angle, avoids the use of lenses in the traditional LED backlight module, effectively shortens the light mixing distance, and makes the thickness of the LED backlight module thinner; on the other hand, the spacing between adjacent LED chips 1 becomes larger, which can reduce the number of LED chips 1 used, and eliminates the phenomenon of uneven brightness, thereby improving the visual effect of the backlight module. It can be understood that the light mixing distance in the present invention refers to the vertical distance between the substrate 7 and the diffuser 8.

[0042] The present invention will be further described below with specific embodiments: Example 1 This embodiment provides an LED packaging structure, including an LED chip and a packaging colloid disposed on the surface of the LED chip; The encapsulation colloid includes a first encapsulation colloid, a second encapsulation colloid and a white glue layer; a dam having a cavity is provided on the upper surface of the LED chip, the first encapsulation colloid is arranged in the cavity of the dam and is flush with the dam; the second encapsulation colloid wraps the surface of the LED chip and is isolated from the first encapsulation colloid by the dam, the height of the second encapsulation colloid is higher than the height of the dam, the first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface, and the white glue layer is arranged in the pit.

[0043] In the pit, the angle θ formed by the dam and the second encapsulation colloid is 120°, the ratio of the thickness of the white glue layer to the thickness of the first encapsulation colloid is 5:1, the height of the dam is 2 / 3 of the thickness of the LED chip, the width of the cavity of the dam is 2 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 of the width of the LED chip.

[0044] Among them, this embodiment also provides a packaging method of the LED packaging structure, including: (1) Place double-sided tape on the steel plate, and fix the LED chips on the carrier plate through the double-sided tape so that the LED chips are arranged in an array; (2) a dam material is provided on the upper surface of each LED chip, and then heated and cured to obtain a dam having a cavity, wherein the heating and curing temperature is 120° C., the heating and curing time is 45 min, and the dam material is transparent silicone; (3) a second encapsulating colloid material is arranged on the steel plate, and firstly a line is drawn in the X direction, and then a line is drawn in the Y direction, so that the second encapsulating colloid wraps the surface of the LED chip 1 outside the dam and fills the gap between adjacent LED chips, and the height is higher than the height of the dam, but does not overflow the dam, as the second encapsulating colloid, so that the second encapsulating colloid forms an inclined surface and is connected to the dam, and the inclined surface serves as the inclined surface of the pit; then, heating and curing are performed to obtain a molded second encapsulating colloid, wherein the heating and curing temperature is 120° C., and the heating and curing time is 45 min; Then, the first encapsulating colloid material is filled in the cavity of the dam, and the height is flush with the dam, as the first encapsulating colloid, forming the bottom surface of the pit, and the bottom surface is in contact with the inclined surface formed by the second encapsulating colloid, forming an inwardly concave pit; then, heating and curing are performed to obtain a molded first encapsulating colloid, wherein the heating and curing temperature is 120° C. and the heating and curing time is 45 minutes; The first packaging colloid material and the second packaging colloid material are transparent silica gel.

[0045] (4) Filling the concave pit with white glue, and then heating and curing the concave pit to obtain a formed white glue layer, wherein the white glue layer is flush with the highest point of the second encapsulation colloid, wherein the heating and curing temperature is 130° C., the heating and curing time is 50 min, and the material of the white glue is transparent silicone.

[0046] (5) Setting a cutting line according to the preset row and column spacing, then cutting along the cutting line and peeling off the double-sided tape to obtain a single LED packaging structure.

[0047] This embodiment further provides an LED backlight module, comprising the LED packaging structure, a substrate and a diffusion sheet, wherein the LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0048] Example 2 This embodiment provides an LED packaging structure, which is different from the embodiment 1 in that: In the pit, the angle θ formed by the dam and the second packaging colloid is 150°, the ratio of the thickness of the white glue layer to the thickness of the first packaging colloid is 6:1, the height of the dam is 1 / 3 of the thickness of the LED chip, the width of the cavity of the dam is 1 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 of the width of the LED chip.

[0049] This embodiment further provides an LED backlight module, comprising the LED packaging structure, a substrate and a diffusion sheet, wherein the LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0050] Example 3 This embodiment provides an LED packaging structure, which is different from the embodiment 1 in that: In the pit, the angle θ formed by the dam and the second packaging colloid is 143°, the ratio of the thickness of the white glue layer to the thickness of the first packaging colloid is 5.6:1, the height of the dam is 1 / 3 of the thickness of the LED chip, the width of the cavity of the dam is 1 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 of the width of the LED chip.

[0051] This embodiment further provides an LED backlight module, comprising the LED packaging structure, a substrate and a diffusion sheet, wherein the LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0052] Example 4 This embodiment provides an LED packaging structure, which is different from the embodiment 1 in that: Among them, the first encapsulating colloid material is a first silicone with adhesion and flexibility, and its refractive index n1=1.5; the second encapsulating colloid material is a second silicone with hardness and elasticity, and its refractive index n2=1.47; the dam material is a third silicone with adhesion, hardness and thixotropy, and its refractive index n3=1.52; the refractive index of the white glue in the white glue layer is n4=1.45, satisfying n3>n1>n2>n4.

[0053] This embodiment further provides an LED backlight module, comprising the LED packaging structure, a substrate and a diffusion sheet, wherein the LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0054] Control group This control group provides a conventional LED packaging structure, the structure of which is as follows Figure 1 As shown, it specifically includes: an LED chip, a bracket arranged around the LED chip, and a packaging glue filled in the bracket and wrapping the LED chip.

[0055] This control group also provides an LED backlight module, including the conventional LED packaging structure, substrate, lens and diffuser, wherein the LED packaging structure is fixed on the substrate and electrically connected to the substrate through wires, the lens covers the LED packaging structure, and the diffuser is located above the LED packaging structure. The working schematic diagram is shown in FIG. Figure 2 shown.

[0056] Performance Testing 1. Light intensity distribution: The light intensity distribution of the LED backlight module obtained in the embodiment and the control group was tested. The test light output angle range of the light intensity distribution was -90°~90°, and the corresponding light intensity distribution curve was drawn with the light output angle as the horizontal coordinate and the relative light intensity as the vertical coordinate.

[0057] Test results see Figure 14~Figure 18 ,in, Fig.14 This is the light intensity distribution curve of the LED backlight module obtained in Example 1. The light output angle is only 120°. Figure 15~Figure 17 The light intensity distribution curves of the LED backlight modules obtained in Examples 2 to 4 are shown in Figures 2 to 4, respectively. The light output angle can reach about 170°. Fig.18 This is the light intensity distribution curve of the LED backlight module obtained in the control group, and the light output angle is only 100°. Figure 14~Figure 18From the comparative analysis, it can be seen that in the present application, a dam is set on the LED chip, a first encapsulation colloid is formed inside the dam, and a second encapsulation colloid is formed outside the dam. The first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface, and then a white glue layer is formed in the pit, which can effectively improve the light output angle. By reasonably selecting the materials of the first encapsulation colloid, the second encapsulation colloid and the dam, the light output angle of the LED backlight module can be improved and the use of lenses can be reduced.

[0058] 2. Light mixing uniformity: The LED backlight modules obtained in Example 3 and the control group were tested.

[0059] Test results see Fig.19 and Fig. 20 ,in, Fig.19 This is the effect diagram of Example 3. Fig. 20 This is the effect diagram of the control group. Fig.19 The light intensity at the edge of the LED chip is close to that directly above it, and the LED backlight module emits light evenly; Fig. 20 The light intensity above the LED chip is strong, while the light intensity at the edge is weak, and the light and dark alternate, and there is obvious uneven light mixing. It can be seen that in this application, a dam is set on the LED chip, a first encapsulation colloid is formed inside the dam, and a second encapsulation colloid is formed outside the dam. The first encapsulation colloid, the dam, and the second encapsulation colloid form a pit with an inclined surface, and then a white glue layer is formed in the pit, which can increase the uniformity of light output.

[0060] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An LED packaging structure, characterized in that: include: An LED chip and a packaging colloid disposed on the surface of the LED chip; The encapsulating colloid comprises a first encapsulating colloid, a second encapsulating colloid and a white glue layer; A dam with a cavity is provided on the upper surface of the LED chip, and the first encapsulation colloid is provided in the cavity of the dam and is flush with the dam; the second encapsulation colloid wraps the surface of the LED chip and is isolated from the first encapsulation colloid by the dam, the height of the second encapsulation colloid is higher than the height of the dam, the first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface, and the white glue layer is provided in the pit.

2. The LED packaging structure according to claim 1, characterized in that: In the pit, an angle formed by the dam and the second encapsulating colloid is 140° to 150°.

3. The LED packaging structure according to claim 1 or 2, characterized in that: The ratio of the thickness of the white glue layer to the thickness of the first encapsulating colloid is 5:1-6:

1.

4. The LED packaging structure according to claim 1, characterized in that: The height of the dam is 1 / 3 to 2 / 3 of the thickness of the LED chip; The width of the cavity of the dam is 1 / 3 to 2 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 to 1 / 3 of the width of the LED chip.

5. The LED packaging structure according to claim 1, characterized in that: The material of the first encapsulating colloid is the first silicone, the material of the second encapsulating colloid is the second silicone, the material of the dam is the third silicone, the refractive index of the first silicone is n1, the refractive index of the second silicone is n2, the refractive index of the third silicone is n3, and the refractive index of the white glue in the white glue layer is n4, satisfying the following formula: n3>n1>n2>n4.

6. A packaging method for the LED packaging structure according to any one of claims 1 to 5, characterized in that: include: (1) Fixing LED chips on the carrier board so that the LED chips are arranged in an array; (2) forming a dam having a cavity on the upper surface of each of the LED chips; (3) forming a first encapsulation colloid and a second encapsulation colloid on the surface of each of the LED chips, wherein the first encapsulation colloid and the second encapsulation colloid are separated by the dam, and the first encapsulation colloid, the dam and the second encapsulation colloid form a pit with an inclined surface; (4) forming a white glue layer in the pit; (5) Cutting is performed according to the preset row and column spacing and separated from the carrier to obtain a single LED packaging structure.

7. The packaging method of the LED packaging structure according to claim 6, characterized in that: The step (3) comprises: (31) In the area outside the dam, a second encapsulating colloid is formed by scribing to wrap the LED chip and have a height higher than the dam, so that the second encapsulating colloid forms an inclined surface and is connected to the dam, and the inclined surface serves as the inclined surface of the pit; (32) A first encapsulating colloid is formed in the cavity of the dam, and the first encapsulating colloid is flush with the dam to form a bottom surface of the pit.

8. The packaging method of the LED packaging structure according to claim 7, characterized in that: The dam with the cavity is formed by heating and curing, the heating and curing temperature is 100° C. to 150° C., and the heating and curing time is 30 min to 60 min; The encapsulation colloid is formed by heating and curing, the heating and curing temperature is 100° C. to 150° C., and the heating and curing time is 30 min to 60 min.

9. An LED backlight module, characterized in that: It comprises the LED packaging structure as described in any one of claims 1 to 5.

10. The LED backlight module according to claim 9, characterized in that: The LED backlight module further comprises a substrate and a diffusion sheet. The LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

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