An LED packaging structure, a packaging method, and a backlight module

Abstract

The present 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 includes an LED chip and a packaging colloid disposed on the surface of the LED chip; the packaging colloid includes a first packaging colloid, a second packaging colloid and a white glue layer; a dam with a cavity is provided on the upper surface of the LED chip, the first packaging colloid is disposed in the cavity of the dam and is flush with the dam; the second packaging colloid wraps the surface of the LED chip and is isolated from the first packaging colloid by the dam, the height of the second packaging colloid is higher than the height of the dam, the first packaging colloid, the dam and the second packaging colloid form a concave pit with an inclined surface, and the white glue layer is disposed in the concave pit. Implementing the present invention can effectively expand the light-emitting angle of the LED chip, improve the light-emitting uniformity of the LED chip, can improve the visual effect of the backlight module, reduce the number of LED chips used, and reduce the thickness.

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] A backlight module generally consists of a substrate, LED lamp beads, a lens, and a diffusion sheet. When a conventional LED packaging structure is used as a backlight source for a display screen, it is necessary to increase its light-emitting angle by means of the refraction of the lens to ensure uniform light mixing in the backlight module. The use of the lens can increase the LED chip spacing, reduce the number of LED chips used, reduce the overall cost of the display screen, and at the same time, can also reduce the light mixing distance and the overall thickness of the display screen, making the display screen thinner and lighter.

[0003] A conventional LED packaging structure mainly consists of a bracket 25, an LED chip 1, wires, and a packaging colloid 2, as Figure 1 shown. It has good directivity, a strong central light intensity, and a weak peripheral light intensity. Its light-emitting angle is small, usually about 100° - 120°. A traditional LED backlight module generally consists of a substrate 7, an LED chip 1, a lens, and a diffusion sheet 8, as Figure 2 shown. When a conventional LED chip is used as a backlight source for a display screen, 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 bright and dark and uneven light mixing. At this time, it is necessary to reduce the spacing between LED chips so that the light-emitting edges of two adjacent LED chips overlap to achieve the same light intensity as directly above the LED chip. After the spacing between LED chips is reduced, more LED chips are required, increasing the cost; or, without reducing the spacing between LED chips, it is necessary to increase the distance between the LED chip and the diffusion plate, that is, increase the light mixing distance, so that the light emitted from the edge of the LED chips is superimposed at a farther place. At this time, the backlight module will be thicker, which is not conducive to the application of thinner and lighter display screens. 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-emitting angle of the LED chip and improve the light-emitting uniformity of the LED chip.

[0005] To solve the above technical problem, in the first aspect of the present invention, an LED packaging structure is provided, including: an LED chip and a packaging colloid disposed on the surface of the LED chip;

[0006] The packaging colloid includes a first packaging colloid, a second packaging colloid, and a white glue layer;

[0007] The upper surface of the LED chip is provided with a dam having a cavity. The first encapsulation colloid is disposed 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 that 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 disposed in the pit.

[0008] As an improvement of the above solution, in the pit, the included angle formed by the dam and the second encapsulation colloid is 140° - 150°.

[0009] As an improvement of the above solution, the ratio of the thickness of the white glue layer to the thickness of the first encapsulation colloid is 5:1 - 6:1.

[0010] As an improvement of the above solution, the height of the dam is 1 / 3 - 2 / 3 of the thickness of the LED chip;

[0011] The width of the cavity of the dam is 1 / 3 - 2 / 3 of the width of the LED chip, and the width of the dam is 1 / 6 - 1 / 3 of the width of the LED chip.

[0012] As an improvement of the above solution, the material of the first encapsulation colloid is the first silicone, the material of the second encapsulation colloid is the second silicone, the material of the dam is the third silicone, the refractive index of the first silicone is n 1 , the refractive index of the second silicone is n 2 , the refractive index of the third silicone is n 3 , the refractive index of the white glue in the white glue layer is n 4 , satisfying the following formula:

[0013] n 3 > n 1 > n 2 > n 4 .

[0014] The second aspect of the present invention also provides a packaging method for the LED packaging structure described above, including:

[0015] (1) Fix the LED chips on the carrier plate so that the LED chips are arranged in an array;

[0016] (2) Form a dam having a cavity on the upper surface of each LED chip;

[0017] (3) Form a first encapsulation colloid and a second encapsulation colloid on the surface of each LED chip. The first encapsulation colloid and the second encapsulation colloid are isolated from each other by the dam, and the first encapsulation colloid, the dam, and the second encapsulation colloid form a pit with an inclined surface;

[0018] (4) Form a white glue layer in the pit;

[0019] (5) Cut according to a preset row and column spacing and separate from the carrier board to obtain a single LED packaging structure.

[0020] As an improvement of the above solution, step (3) includes:

[0021] (31) In the area outside the dam, form a second encapsulation colloid that wraps the LED chip and has a height higher than that of the dam by scribing, so that the second encapsulation colloid forms an inclined surface and is connected to the dam, and the inclined surface serves as the inclined surface of the pit;

[0022] (32) Form a first encapsulation colloid in the cavity of the dam, and the first encapsulation colloid is flush with the dam to form the bottom surface of the pit.

[0023] As an improvement of the above solution, the dam with a 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;

[0024] 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.

[0025] The third aspect of the present invention also provides an LED backlight module, including at least one of the above-mentioned LED packaging structures.

[0026] 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.

[0027] Implementing the present invention has the following beneficial effects:

[0028] (1) In the present invention, the LED chip is a flip chip, 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 that 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, effectively expanding the light-emitting angle of the LED chip, increasing the light intensity at the edge, making the light mixing uniform, eliminating the phenomenon of uneven brightness and darkness, shortening the light mixing distance, and reducing the number of LED chips used.

[0029] (2) The present invention provides an LED backlight module, which can avoid the use of a lens assembly, has a short light mixing distance, and requires a small number of LED chips. It not only has uniform light mixing, improves the visual effect of the backlight module, but also reduces the thickness of the LED backlight module, facilitating the preparation of a lighter and thinner LED backlight module. In addition, implementing the LED backlight module in this application also reduces costs in multiple aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : Schematic structural diagram of an LED packaging structure in the prior art;

[0031] Figure 2 : Schematic working diagram of an LED backlight module in the prior art;

[0032] Figure 3 : Schematic structural diagram of an LED packaging structure in the present invention;

[0033] Figure 4 : Schematic working diagram of step (1) in the present invention;

[0034] Figure 5 : Top view of the LED packaging structure after step (1) in the present invention is completed;

[0035] Figure 6 : Schematic working diagram of step (2) in the present invention;

[0036] Figure 7 : Top view of the LED packaging structure after step (2) in the present invention is completed;

[0037] Figure 8 : Schematic working diagram of step (31) in the present invention;

[0038] Figure 9 : Schematic working diagram of step (32) in the present invention;

[0039] Figure 10 : Schematic working diagram of step (4) in the present invention;

[0040] Figure 11 : Schematic working diagram of the cutting operation in step (5) in the present invention;

[0041] Figure 12 : Schematic structural diagram of the LED packaging structure after the cutting operation in step (5) in the present invention is completed;

[0042] Figure 13 : Schematic working diagram of the LED backlight module in the present invention;

[0043] Figure 14 : Light intensity distribution curve diagram of the LED packaging structure provided in Embodiment 1 of the present invention;

[0044] Figure 15 : Light intensity distribution curve of the LED packaging structure provided in Embodiment 2 of the present invention;

[0045] Figure 16 : Light intensity distribution curve of the LED packaging structure provided in Embodiment 3 of the present invention;

[0046] Figure 17 : Light intensity distribution curve of the LED packaging structure provided in Embodiment 4 of the present invention;

[0047] Figure 18 : Light intensity distribution curve of the LED packaging structure provided in the control group of the present invention;

[0048] Figure 19 : Light mixing effect diagram of the LED backlight module provided in Embodiment 3 of the present invention;

[0049] Figure 20 : Light mixing effect diagram of the LED backlight module provided in the control group of the present invention.

[0050] Reference numerals: 1 - LED chip; 2 - encapsulation colloid; 21 - first encapsulation colloid; 22 - second encapsulation colloid; 23 - white glue layer; 24 - pit; 25 - bracket; 3 - dam; 4 - carrier plate; 5 - adhesive layer; 6 - cutting line; 7 - substrate; 8 - diffusion sheet. Detailed implementation manners

[0051] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with specific embodiments.

[0052] To solve the above problems, a first aspect of the present invention provides an LED packaging structure. Please refer to Figure 3 , including: an LED chip 1 and an encapsulation colloid 2 provided on the surface of the LED chip 1, and the LED chip 1 is a flip chip. The encapsulation colloid 2 can protect the LED chip 1 from the influence of moisture, dust, chemical substances, external forces, etc. in the external environment, and ensure the reliability and service life of the LED chip 1.

[0053] Among them, the encapsulation colloid 2 includes a first encapsulation colloid 21, a second encapsulation colloid 22 and a white glue layer 23. A dam 3 with a cavity is arranged on the upper surface of the LED chip 1. 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 that 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.

[0054] In the present invention, the setting of the dam 3 can exist as a barrier ring, which is convenient for arranging 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 thus it is easy to form a pit 24 with an inclined surface. And forming the white glue layer 23 in the pit 24 can make the light emitted by the LED chip 1 be emitted around after being reflected by the white glue layer 23, expanding the light-emitting angle of the LED chip 1. At the same time, the light intensity at the edge is increased, the light mixing is made uniform, and the distance between adjacent LED chips 1 is also increased, reducing the number of LED chips 1 arranged.

[0055] Preferably, in the pit 24, the included 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, and thus improves the reflection ability of the LED light output, and further expands the light-emitting angle of the LED chip 1.

[0056] Furthermore, the thickness H of the white glue layer 23 1 and the thickness H of the first encapsulation colloid 21 2 have a ratio of 5:1-6:1. The white glue layer 23 with an appropriate thickness can cause constructive interference between the reflected lights, enhancing the reflection effect. Thus, under the reflection of the white glue layer 23, the luminous intensity at the edge of the LED chip 1 can be increased.

[0057] Even further, the height H of the dam 3 3 is 1 / 3-2 / 3 of the thickness H of the LED chip 1 4 ; the width W of the dam 3 1 is 1 / 6-1 / 3 of the width W of the LED chip 1 2 ; the width W of the cavity of the dam 3 3 is the width W of the LED chip 1 21 / 3 to 2 / 3 of it, so that an appropriate included 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 total internal reflection occurring in the LED chip 1, improving the light extraction efficiency, and increasing the light-emitting angle of the LED chip 1 from about 120° in the conventional case to about 170°. It can be understood that the shape of the dam 3 can be circular, rectangular, rounded rectangular, etc. The second encapsulation colloid 22 can be disposed only on the side surface of the LED chip 1, or can be disposed on the side surface and part of the upper surface of the LED chip 1, specifically according to the width W of the dam 3 1 , the width W of the cavity 3 and the shape of the dam are determined, and the width W of the dam 3 1 and the width W of the cavity 3 can be appropriately adjusted according to specific requirements.

[0058] It can be understood that the materials of the first encapsulation colloid 21, the second encapsulation colloid 22, and the dam 3 are all preferably silica gels with high light transmittance, having strong adhesiveness to each other, enhancing the airtightness of the LED encapsulation chip, and reducing the penetration path of impurities such as air into the LED chip 1. Exemplarily, the silica gel is selected from one of transparent silica gel and fluorescent gel. The transparent silica gel has a relatively high refractive index, which can reduce the loss of photons at the interface between the LED chip 1 and air and improve the light extraction efficiency; the fluorescent gel is a silica gel dispersed with phosphor, and the phosphor is evenly distributed in the silica gel, which can change the light output color and improve the light color uniformity.

[0059] Optionally, the material of the first encapsulation colloid 21 is the first silica gel. The first silica gel has certain adhesiveness and flexibility, enabling the first encapsulation colloid 21 to be tightly adhered to the upper surface of the LED chip 1 and the white glue layer 23, avoiding problems such as delamination and pores, and at the same time adapting to the thermal expansion and contraction and mechanical stress changes during the processing and use of the LED encapsulation structure; more preferably, the adhesion strength of the first silica gel on the LED chip 1 is 3 MPa to 4 MPa, and the adhesion strength on the white glue layer 23 is 2.5 MPa to 3.5 MPa. The material of the second encapsulation colloid 22 is the second silica gel. The second silica gel has certain hardness and elasticity, providing sufficient support for the LED chip 1 and resisting external impact forces to prevent deformation, and at the same time having certain viscosity to facilitate the formation of a smooth inclined surface; more preferably, the Shore A hardness of the second silica gel is 40 to 60. The material of the dam 3 is the third silica gel. The third silica gel has certain adhesiveness, hardness and thixotropy, so as to form a blocking ring and form the first encapsulation colloid 21 and the second encapsulation colloid 22 with preset requirements based on this, better controlling the light propagation path; more preferably, the hardness of the third silica gel is less than the hardness of the second silica gel.

[0060] Further, the refractive index of the first silicone gel is n 1 , the refractive index of the second silicone gel is n 2 , the refractive index of the third silicone gel is n 3 , the refractive index of the white glue in the white glue layer 23 is n 4 , satisfying the following formula: n 3 > n 1 > n 2 > n 4 . By limiting the refractive indices of the first silicone gel, the second silicone gel, the third silicone gel, 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 encapsulation colloid 21 after refraction at a large angle, and then is reflected by the white glue layer 23 and emitted from the side, and also from the center position of the first encapsulation colloid 21; part of the light-emitting light enters the dam 3 after refraction at a small angle, and then is reflected by the white glue layer 23 and emitted from the side, and also from the center position of the dam 3, maintaining the light intensity in the middle area and strengthening the light intensity near the edge; the remaining part of the light enters the second encapsulation colloid 22 after refraction at a large angle, and then is reflected by the white glue layer 23 and emitted from the side, thereby overall increasing the light-emitting angle of the LED chip 1 and weakening the alternation of light intensity between the middle and the edge.

[0061] Correspondingly, the present invention also provides a packaging method for the LED packaging structure described above, including:

[0062] (1) Fix the LED chip 1 on the carrier plate 4 so that the LED chips 1 are arranged in an array;

[0063] (2) Form a dam 3 with a cavity on the upper surface of each LED chip 1;

[0064] (3) Form a first encapsulation colloid 21 and a second encapsulation colloid 22 on the surface of each LED chip 1. The first encapsulation colloid 21 and the second encapsulation colloid 22 are isolated by the dam 3, and the first encapsulation colloid 21, the dam 3, and the second encapsulation colloid 22 form a concave pit 24 with an inclined surface;

[0065] (4) Form a white glue layer 23 in the concave pit 24;

[0066] (5) Cut according to a preset row and column pitch and separate from the carrier plate 4 to obtain a single LED packaging structure.

[0067] The following is a specific elaboration for each step. Please refer to Figures 4 to 13 :

[0068] Regarding (1), fixing the LED chip 1 on the carrier plate 4 so that the LED chips 1 are arranged in an array, please refer toFigure 4 and Figure 5 ;

[0069] Specifically, an adhesive layer 5 for fixing the LED chip 1 is provided between the carrier plate 4 and the LED chip 1. Preferably, the carrier plate 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 plate 4, and is easy to peel off from the carrier plate 4 later, and the performance of the LED chip 1 will not be damaged during the peeling process, and the substrate 7 is also easy to clean and can be reused repeatedly. In some embodiments, the adhesive layer 5 is provided on the entire steel plate.

[0070] Regarding (2), for forming a dam 3 with a cavity on the upper surface of each LED chip 1, please refer to Figure 6 and Figure 7 ;

[0071] Specifically, dam 3 material, preferably the third silicone, is provided on the upper surface of each LED chip 1, and then, heating and curing are carried out to obtain the formed dam 3 with a cavity. Further, the heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30 min to 60 min.

[0072] Further, the height H of the dam 3 3 is 1 / 6 to 1 / 3 of the thickness H of the LED chip 1 4 , and the width W of the cavity of the dam 3 3 is 1 / 3 to 2 / 3 of the width W of the LED chip 1 2 .

[0073] 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 isolated 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;

[0074] Preferably, the step (3) includes:

[0075] (31) In the area outside the dam 3, a second encapsulation colloid 22 that wraps the LED chip 1 and has a height higher than the height of the dam 3 is formed by scribing, so that the second encapsulation colloid 22 forms an inclined surface and is connected to the dam 3, and the inclined surface serves as the inclined surface of the pit 24. Please refer to Figure 8 ;

[0076] Specifically, on the carrier plate 4, the second encapsulation colloid 22 material, preferably the second silicone, is provided 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 H of the dam 33 , but the second silicone does not overflow the dam 3 to form the inclined surface of the concave pit 24. According to the setting position and shape of the dam 3 on the upper surface of the LED chip 1, the second encapsulation 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.

[0077] Further, the second silicone is provided on the LED chip 1 by scribing to form a semi-finished product of the second encapsulation colloid 22. Subsequently, heating and curing are performed to obtain the formed second encapsulation colloid 22. The heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30 min to 60 min. In some embodiments, scribing is first performed in the X direction and then in the Y direction when forming the inclined surface; in other embodiments, scribing is first performed in the Y direction and then in the X direction when forming the inclined surface.

[0078] (32) Form the first encapsulation colloid 21 in the cavity of the dam 3, and the first encapsulation colloid 21 is flush with the dam 3 to form the bottom surface of the concave pit 24. Please refer to Figure 9 ;

[0079] Specifically, the cavity of the dam 3 is filled with the material of the first encapsulation colloid 21, preferably the first silicone. The first encapsulation colloid 21 and the dam 3 can form the bottom surface of the concave pit 24. The bottom surface is connected to the inclined surface formed by the second encapsulation colloid 22 to form an inwardly concave pit 24. Subsequently, heating and curing are performed to obtain the formed first encapsulation colloid 21. The heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30 min to 60 min. It can be understood that the first encapsulation colloid 21 can also be slightly higher or slightly lower than the dam 3.

[0080] Regarding (4), form the white glue layer 23 in the concave pit 24. Please refer to Figure 10 ;

[0081] Specifically, white glue is filled in the concave pit 24. Subsequently, heating and curing are performed to obtain the formed white glue layer 23. The heating and curing temperature is 100°C to 150°C, and the heating and curing time is 30 min to 60 min. The thickness H of the cured white glue layer 23 1 can be flush with the highest point of the second encapsulation colloid 22, or can be slightly higher or slightly lower than the highest point of the second encapsulation colloid 22.

[0082] Regarding (5), cutting is performed according to the preset row and column spacing and separating from the carrier plate 4 to obtain a single LED encapsulation structure. Please refer to Figure 11 , Figure 12 and Figure 3 ;

[0083] Specifically, the entire LED packaging structure is cut along the set cutting line 6 to obtain single LED packaging structures, and the cutting line 6 can be set according to the row and column spacing.

[0084] Correspondingly, the present invention also provides an LED backlight module including the LED packaging structure described above.

[0085] Furthermore, the LED backlight module further includes a substrate 7 and a diffusion sheet 8. The LED packaging structure is fixed on the substrate 7, and the diffusion sheet 8 is located above the LED packaging structure. Please refer to Figure 13 。

[0086] Specifically, the substrate 7 has opposite front and back surfaces, the LED packaging structure has opposite bottom and top surfaces, 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 provided between the LED packaging structure and the diffusion sheet 8.

[0087] Compared with traditional LED backlight modules, the use of the above LED packaging structure in the present invention, on the one hand, expands the light-emitting angle, avoids the use of lenses in traditional LED backlight modules, 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 and darkness, 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 diffusion sheet 8.

[0088] The following further illustrates the present invention with specific embodiments:

[0089] Embodiment 1

[0090] This embodiment provides an LED packaging structure, including an LED chip and a packaging colloid provided on the surface of the LED chip;

[0091] The packaging colloid includes a first packaging colloid, a second packaging colloid, and a white glue layer; a dam with a cavity is provided on the upper surface of the LED chip, the first packaging colloid is provided in the cavity of the dam and is flush with the dam; the second packaging colloid wraps the surface of the LED chip and is isolated from the first packaging colloid by the dam, the height of the second packaging colloid is higher than the height of the dam, the first packaging colloid, the dam, and the second packaging colloid form a concave pit with an inclined surface, and the white glue layer is provided in the concave pit.

[0092] In the pit, the included 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. The width of the dam is 1 / 6 of the width of the LED chip.

[0093] Wherein, this embodiment also provides a packaging method for the LED packaging structure, including:

[0094] (1) Set 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;

[0095] (2) Set dam material on the upper surface of each LED chip, and then, carry out heating and curing and shaping to obtain a formed dam with a cavity. Among them, the heating and curing temperature is 120°C, the heating and curing time is 45 min, and the dam material is transparent silica gel;

[0096] (3) Set the second encapsulation colloid material on the steel plate, first draw a line in the X direction, and then draw a line in the Y direction, so that it 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 encapsulation colloid, so that the second encapsulation colloid forms an inclined surface and is connected to the dam, and the inclined surface serves as the inclined surface of the pit; then, carry out heating and curing and shaping to obtain a formed second encapsulation colloid. Among them, the heating and curing temperature is 120°C, and the heating and curing time is 45 min;

[0097] Then, fill the cavity of the dam with the first encapsulation colloid material, and the height is flush with the dam, as the first encapsulation colloid, to form the bottom surface of the pit. The bottom surface is in contact with the inclined surface formed by the second encapsulation colloid to form an inwardly concave pit; then, carry out heating and curing and shaping to obtain a formed first encapsulation colloid. Among them, the heating and curing temperature is 120°C, and the heating and curing time is 45 min;

[0098] The first encapsulation colloid material and the second encapsulation colloid material are transparent silica gel.

[0099] (4) Fill white glue in the pit, and then, carry out heating and curing and shaping to obtain a formed white glue layer. The white glue layer is flush with the highest point of the second encapsulation colloid. Among them, 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 silica gel.

[0100] (5) Set cutting lines according to the preset row and column spacing, then cut along the cutting lines, and peel off the double-sided tape to obtain single LED packaging structures.

[0101] This embodiment also provides an LED backlight module, including the LED packaging structure, 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.

[0102] Embodiment 2

[0103] This embodiment provides an LED packaging structure, which is different from that of Embodiment 1 in that:

[0104] In the pit, the included angle θ formed by the dam and the second encapsulation colloid is 150°, the ratio of the thickness of the white glue layer to the thickness of the first encapsulation 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.

[0105] This embodiment also provides an LED backlight module, including the LED packaging structure, 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.

[0106] Embodiment 3

[0107] This embodiment provides an LED packaging structure, which is different from that of Embodiment 1 in that:

[0108] In the pit, the included angle θ formed by the dam and the second encapsulation colloid is 143°, the ratio of the thickness of the white glue layer to the thickness of the first encapsulation 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.

[0109] This embodiment also provides an LED backlight module, including the LED packaging structure, 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.

[0110] Embodiment 4

[0111] This embodiment provides an LED packaging structure, which is different from that of Embodiment 1 in that:

[0112] Among them, the first encapsulation colloid material is a first silicone rubber with adhesiveness and flexibility, and the refractive index n 1 = 1.5. The second encapsulation colloid material is a second silicone rubber with hardness and elasticity, and the refractive index n 2= 1.47, the dam material is the third silicone with adhesiveness, hardness and thixotropy, refractive index n 3 = 1.52, the refractive index n of the white glue in the white glue layer 4 = 1.45, satisfying n 3 > n 1 > n 2 > n 4 。

[0113] This embodiment also provides an LED backlight module, including the LED packaging structure, a substrate and a diffusion sheet as described above. The LED packaging structure is fixed on the substrate, and the diffusion sheet is located above the LED packaging structure.

[0114] Control group

[0115] This control group provides a conventional LED packaging structure, and its structure is as Figure 1 shown, specifically including: an LED chip, a bracket arranged around the LED chip, and a packaging glue filled in the bracket and wrapping the LED chip.

[0116] This control group also provides an LED backlight module, including the above-mentioned conventional LED packaging structure, a substrate, a lens and a diffusion sheet. The LED packaging structure is fixed on the substrate and is electrically connected to the substrate through a wire. The lens covers the LED packaging structure, and the diffusion sheet is located above the LED packaging structure. Its working schematic diagram is as Figure 2 shown.

[0117] Performance test

[0118] 1. Light intensity distribution: Test the light intensity distribution of the LED backlight modules obtained in the embodiments and the control group. The light-emitting angle range for testing the light intensity distribution is -90° to 90°, and a corresponding light intensity distribution curve is plotted with the light-emitting angle as the abscissa and the relative light intensity as the ordinate.

[0119] The test results are shown in Figures 14 to 18 , among which, Figure 14 is the light intensity distribution curve of the LED backlight module obtained in Example 1, and the light-emitting angle is only 120°, Figures 15 to 17 are respectively the light intensity distribution curves of the LED backlight modules obtained in Examples 2 to 4, and the light-emitting angles can all reach about 170°, while Figure 18 is the light intensity distribution curve of the LED backlight module obtained in the control group, and the light-emitting angle is only 100°. Through Figures 14 to 18Through comparative analysis, it can be seen that in the present application, a dam is provided on the LED chip, a first encapsulation colloid is formed within 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 concave pit with an inclined surface. Subsequently, a white glue layer is formed within the concave pit, which can effectively increase the light-emitting angle. By reasonably selecting the materials of the first encapsulation colloid, the second encapsulation colloid, and the dam, the light-emitting angle of the LED backlight module can be increased, and the use of lenses can be reduced.

[0120] 2. Light mixing uniformity: The LED backlight modules obtained in Example 3 and the control group were tested.

[0121] The test results are shown in Figure 19 and Figure 20 , where Figure 19 is the effect diagram of Example 3, Figure 20 is the effect diagram of the control group. By comparison, it is found that Figure 19 the light intensity at the edge of the LED chip is close to the light intensity directly above, and the light emission of the LED backlight module is uniform; Figure 20 the light intensity directly above the LED chip in

[0122] is strong, while the light intensity at the edge is weak, with bright and dark alternating, and there is obvious non-uniform light mixing. It can be seen that in the present application, a dam is provided on the LED chip, a first encapsulation colloid is formed within 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 concave pit with an inclined surface. Subsequently, a white glue layer is formed within the concave pit, which can increase the uniformity of light emission.

[0122] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by 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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