Light-emitting diode packaging structure and preparation method therefor

Abstract

The present application provides a light-emitting diode packaging structure and a preparation method therefor. The light-emitting diode packaging structure comprises a light-emitting diode chip, a color conversion film and a first reflective film, wherein the color conversion film is disposed on a light-emitting surface of the light-emitting diode chip; the first reflective film is disposed on a sidewall of the color conversion film; and the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer, which are sequentially stacked on the light-emitting surface of the light-emitting diode chip. The present application can reduce a light emission angle, improve a color temperature and increase the yield.

Description

A light emitting diode package structure and a preparation method thereof

[0001] This application claims priority to the Chinese patent application No. 202411381134.2, filed on September 30, 2024, and entitled "A light emitting diode package structure and a preparation method thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of semiconductor, in particular to a light emitting diode package structure and a preparation method thereof. BACKGROUND

[0003] Light emitting diode (LED) has the advantages of small size, long service life, energy saving and environmental protection, fast response speed and strong durability, and is widely used in automobile, indoor lighting, traffic signal lamp, display device and other fields. It is an ideal light source to replace traditional light source. The light emitting diode package structure usually includes an LED chip and a color conversion layer. The LED chip can generate basic light of a specific wavelength. The color conversion particles in the color conversion layer can absorb the basic light of the specific wavelength and convert it into light of other wavelengths, thereby realizing the color conversion function and achieving the purpose of adjusting the actual light color of the light emitting diode package structure. The light emitting diode package structure can be roughly divided into direct insertion package, surface mount device (SMD) package, chip on board (COB) package and chip scale package (CSP) according to the emergence time of the package form. CSP is a package form based on the development of flip chip LED technology in recent years. It has the advantages of small package size and large effective light emitting area, and has broad market application prospects.

[0004] Taking a CSP LED packaging structure applying an inverted LED chip as an example, the front surface and the side surface of the conventional CSP LED packaging structure both emit light, which can be understood as five-surface light emission. This leads to the problems of large light emission angle and weak front surface light emission intensity of the CSP LED packaging structure, making it difficult to be applied in illumination and display products with higher precision requirements on light emission angle and strong requirements on front surface light emission intensity. In order to solve the problems, the applicant adopts a method of plating a reflective film on the side wall of the color conversion layer in the internal research and development to reduce the light emission angle and increase the front surface light emission, which makes the side wall plating film quality a key factor affecting the light emission angle and the front surface light emission intensity of the CSP LED packaging structure. Further, the applicant finds in the internal research and development that, in order to improve the side wall plating film quality on the basis of ensuring yield, a method of plating the film on the surface and the side surface as a whole is needed to complete the plating process, and then the reflective film on the surface is removed by grinding. However, the grinding error in the grinding process is inevitable, which further leads to the removal of at least part of the color conversion layer in the process of removing the reflective film on the front surface of the color conversion layer by grinding.

[0005] On the basis of the above internal research, the applicant finds that the current color conversion layer is usually a fluorescent adhesive film or a ceramic glass fluorescent sheet. The fluorescent adhesive film is formed by uniformly mixing fluorescent powder in a transparent adhesive layer and curing, and the ceramic glass fluorescent sheet is formed by co-sintering of fluorescent powder and ceramic glass material, which makes the fluorescent powder in the color conversion layer in a dispersed state. When at least part of the color conversion layer is removed by grinding, problems such as loss of fluorescent powder in local areas, poor morphology of the light emission surface formed by grinding, and the like, which affect the color temperature interval and product yield, will occur, and the problems need to be solved urgently. TECHNICAL PROBLEM

[0006] The present application provides a light emitting diode packaging structure and a preparation method thereof, which can effectively solve the problem that the light emitting diode packaging structure in the related art cannot reduce the light emission angle and improve the front surface light emission brightness while taking into account the color temperature interval and yield. SOLUTION

[0007] In a first aspect, the present application provides a light emitting diode packaging structure, comprising: a light emitting diode chip; a color conversion film disposed on the light emitting surface of the light emitting diode chip; and a first reflective film disposed on the side wall of the color conversion film; wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer which are sequentially stacked on the light emitting surface of the light emitting diode chip.

[0008] In a second aspect, the present application provides a preparation method of a light emitting diode packaging structure, the preparation method of the light emitting diode packaging structure comprising the following steps: disposing a light emitting diode chip and a color conversion film on a supporting table coated with a UV debonding film on a surface, wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer; depositing a first reflective film on one surface and each side wall of the color conversion film, and depositing a second reflective film on one surface and each side wall of the light emitting diode chip; removing the first reflective film on the surface of the color conversion film by grinding, and removing the second reflective film on the surface of the light emitting diode chip by grinding; forming a bonding layer on a light emitting surface of the light emitting diode chip, disposing the color conversion film on the bonding layer, and performing a baking treatment to fix the color conversion film on the light emitting surface of the light emitting diode chip. Advantages

[0009] The present application provides a light emitting diode packaging structure and a preparation method thereof, the light emitting diode packaging structure comprising a light emitting diode chip, a color conversion film and a first reflective film, the color conversion film being disposed on a light emitting surface of the light emitting diode chip, and the first reflective film being disposed on a side wall of the color conversion film; wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer which are sequentially stacked on the light emitting surface of the light emitting diode chip. In the light emitting diode packaging structure provided by the present application, the first reflective film disposed on the side wall of the color conversion film can reduce the light emitting angle, increase the front light emission, and since the color conversion layer is provided with a transparent protective layer on the outside, the color conversion layer can be protected during the grinding process, so that the color temperature interval of the light emitting diode packaging structure is in a normal range, and the production yield of the light emitting diode packaging structure is improved. BRIEF DESCRIPTION OF DRAWINGS

[0010] The technical solutions and other advantages of the present application will be apparent from the following detailed description of the specific embodiments of the present application, taken in conjunction with the accompanying drawings.

[0011] Fig. 1 is a cross-sectional schematic view of a light emitting diode packaging structure according to some embodiments of the present application.

[0012] Fig. 2 is a cross-sectional schematic view of another light emitting diode packaging structure according to some embodiments of the present application.

[0013] Fig. 3 is a cross-sectional schematic view of a light emitting diode chip according to some embodiments of the present application.

[0014] Fig. 4 is a flowchart of a preparation method of a light emitting diode packaging structure according to some embodiments of the present application.

[0015] FIGS. 5a-5e are schematic diagrams corresponding to steps S10-S50 of some embodiments of the present application.

[0016] FIG. 6 is a flowchart of another method for manufacturing a light emitting diode package structure according to some embodiments of the present application.

[0017] FIGS. 7a-7d are schematic diagrams corresponding to steps M10-M40 of some embodiments of the present application.

[0018] Legend of reference signs:

[0019] Light emitting diode chip 11; light emitting surface Q1 of the light emitting diode chip; substrate layer 111; bump structure Z1; chip body 112; buffer layer X1; first type semiconductor layer X2; light emitting layer X3; second type semiconductor layer X4; electrode layer X5; first electrode X51; second electrode X52; current spreading layer X6; ohmic contact layer X7; current blocking layer X8; color conversion film 12; first transparent protective layer 121; color conversion layer 122; second transparent protective layer 123; first reflective film 13; second reflective film 14; adhesive layer 15; support table 16; UV debonding film 17. Embodiments of the present application

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0021] The terms "first", "second" in the specification are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0022] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, or electrical connection or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplifying the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0024] FIG. 1 is a schematic cross-sectional view of a light emitting diode packaging structure according to some embodiments of the present application; FIG. 2 is a schematic cross-sectional view of another light emitting diode packaging structure according to some embodiments of the present application. Referring to FIGS. 1 and 2, the present application provides a light emitting diode packaging structure, which includes a light emitting diode chip 11, a color conversion film 12, and a first reflective film 13, wherein the color conversion film 12 is disposed on the light emitting surface Q1 of the light emitting diode chip 11; the first reflective film 13 is disposed on the side wall of the color conversion film 12; wherein the color conversion film 12 includes a first transparent protective layer 121, a color conversion layer 122, and a second transparent protective layer 123, which are sequentially stacked on the light emitting surface Q1 of the light emitting diode chip 11.

[0025] In the light emitting diode packaging structure provided by the present application, the first reflective film 13 disposed on the side wall of the color conversion film 12 can reduce the light emitting angle, increase the front light emission, and because the color conversion layer 122 is provided with a transparent protective layer on the outside, the color conversion layer 122 can be protected by the transparent protective layer during the grinding process, avoiding the problem of color conversion particle loss caused by direct contact between the color conversion particles in the color conversion layer 122 and the grinding equipment during the grinding process, thereby enabling the color temperature interval of the light emitting diode packaging structure to be within the normal range, ensuring the color rendering accuracy and stability of the light emitting diode packaging structure, and improving the production yield of the light emitting diode packaging structure.

[0026] In addition, because the color conversion layer 122 is sandwiched between two transparent protective layers, compared with the structure in which the color conversion particles are uniformly dispersed in the color conversion film 12, more light emitted by the color conversion particles can be reflected on the first reflective film 13 on the side wall of the color conversion film 12, thereby improving the narrowing effect of the light emitting angle of the light emitting diode packaging structure. For example, through actual testing, the actual light emitting angle of the light emitting diode packaging structure provided by the present application can reach below 140°, or even below 120°.

[0027] In some embodiments of the present application, the light emitting diode chip 11 can generate basic light of a specific wavelength, and the color conversion film 12 arranged on the light emitting surface Q1 of the light emitting diode chip 11 can absorb the basic light of the specific wavelength and convert it into light of other wavelengths, thereby realizing the color conversion function. For example, the basic light can be blue light in the blue light band, and the color conversion particles in the color conversion film 12 arranged on the light emitting surface Q1 of the light emitting diode chip 11 can be yellow fluorescent powder, which can absorb part of the blue light and convert it into yellow light in the yellow light band, so that the light emitting diode package structure can emit white light. For example, the basic light can be blue light in the blue light band, and the color conversion particles in the color conversion film 12 arranged on the light emitting surface Q1 of the light emitting diode chip 11 can include red quantum dots and green quantum dots, the red quantum dots can absorb part of the blue light and convert it into red light in the red light band, and the green quantum dots can absorb part of the blue light and convert it into green light in the green light band, so that the light emitting diode package structure can emit white light. Of course, in other embodiments of the present application, the light emitting diode chip 11 can also be other chips other than blue light LED chips, and the color conversion particles can also be other color conversion materials other than yellow fluorescent powder and red-green quantum dots.

[0028] In some embodiments of the present application, the color conversion film 12 has a certain thickness and a shape of hexahedron or similar hexahedron, the color conversion film 12 includes oppositely arranged first and second surfaces and four side surfaces between the first and second surfaces, the first surface is located between the light emitting surface Q1 of the light emitting diode chip 11 and the second surface, and the four side surfaces are four side walls of the color conversion film 12. At least part of the light emitted from the light emitting surface Q1 of the light emitting diode chip 11 will irradiate the four side surfaces, and since the first reflective film 13 is arranged on the side walls of the color conversion film 12, the first reflective film 13 can be used to reflect the light, thereby increasing the amount of light emitted from the second surface, thereby reducing the light emitting angle of the light emitting diode package structure, improving the front light emitting amount of the light emitting diode package structure, and improving the front brightness.

[0029] In some embodiments of the present application, the first reflective film 13 covers the side walls of the color conversion film 12, and the thickness of the second transparent protective layer 123 is different from the thickness of the first transparent protective layer 121.

[0030] The light emitting diode packaging structure provided by the embodiments of the present application is provided with the first reflective film 13 on the side wall of the color conversion film 12. However, the applicant has found in the internal research and development that the existing process is difficult to realize the film coating only on the side wall of the color conversion film 12 while ensuring the film coating quality of the side wall. The film coating process needs to be completed in the way of surface + side whole film coating to improve the film coating quality of the side wall, so that the first reflective film 13 covers the side wall of the color conversion film 12. Further, the reflective film on the surface of the color conversion film 12 will affect the light emission, and therefore, the reflective film on the surface of the color conversion film 12 needs to be removed. However, the film removal by stripping or other methods will directly deteriorate the film coating quality of the side wall of the color conversion film 12, so that the first reflective film 13 cannot cover the side wall of the color conversion film 12. The applicant has found through comprehensive evaluation and testing that the way of grinding to remove the reflective film on the surface of the color conversion film 12 can completely remove the reflective film on the surface of the color conversion film 12 while ensuring the film coating quality of the reflective film on the side wall of the color conversion film 12, realizing the technical effect that the side wall of the color conversion film 12 is covered by the first reflective film 13, and further ensuring that the light emission angle can be effectively narrowed and the front light emission brightness can be effectively improved.

[0031] The applicant further finds that in order to enable the reflective film on the surface of the color conversion film 12 to be completely removed, it is necessary to introduce a certain polishing error, or at least polish away at least part of the protective layer. Therefore, as shown in FIG. 1, when the process of first coating the surface of the first transparent protective layer 121 having a basic thickness and the sidewall of the color conversion film 12 in its entirety, and then polishing to remove the reflective film on the surface of the first transparent protective layer 121 is adopted, the first transparent protective layer 121 will be polished away in part, that is, the first transparent protective layer 121 will have a thickness loss, so that the thickness of the finally formed first transparent protective layer 121 is less than the basic thickness, while the second transparent protective layer 123 will not have a thickness loss and still has the basic thickness, thereby making the thickness of the first transparent protective layer 121 less than the thickness of the second transparent protective layer 123, that is, the thickness of the second transparent protective layer 123 is different from the thickness of the first transparent protective layer 121; as shown in FIG. 2, when the process of first coating the surface of the second transparent protective layer 123 having a basic thickness and the sidewall of the color conversion film 12 in its entirety, and then polishing to remove the reflective film on the surface of the second transparent protective layer 123 is adopted, the second transparent protective layer 123 will be polished away in part, that is, the second transparent protective layer 123 will have a thickness loss, so that the thickness of the finally formed second transparent protective layer 123 is less than the basic thickness, while the first transparent protective layer 121 will not have a thickness loss and still has the basic thickness, thereby making the thickness of the second transparent protective layer 123 less than the thickness of the first transparent protective layer 121, that is, the thickness of the second transparent protective layer 123 is different from the thickness of the first transparent protective layer 121.

[0032] Therefore, the present application can enable the first reflective film 13 to coat the sidewall of the color conversion film 12, achieve the technical effect that the light emitting angle is effectively narrowed and the front light emitting brightness is effectively improved. In addition, although the realization that the first reflective film 13 coats the sidewall of the color conversion film 12 depends on the process of first coating in its entirety on the surface and the sidewall, and then polishing to remove the reflective film on the surface of the color conversion film 12, the present application utilizes the sandwich structure color conversion film, by sacrificing at least part of the protective layer (which can be the first transparent protective layer 121 or the second transparent protective layer 122), makes the thickness of the second transparent protective layer 123 different from the thickness of the first transparent protective layer 121, guarantees the performance stability of the color conversion layer 122 in the color conversion film 12, and further enables the color temperature range of the light emitting diode packaging structure to be better controlled, so that the color rendering of the light emitting diode packaging structure is more accurate and the production yield is higher.

[0033] In some embodiments of the present application, the first reflective film 13 is a metal reflective film, such as a silver reflective film, to reflect the light irradiated on the four sides of the color conversion film 12 by using the high reflectivity of the silver reflective film at multiple angles, thereby increasing the front light output of the light emitting diode package structure and improving the front brightness.

[0034] In some embodiments of the present application, the first reflective film 13 is a DBR reflective film, which includes a plurality of first oxide reflective layers and a plurality of second oxide reflective layers stacked together, and the refractive indexes of the first oxide reflective layers and the second oxide reflective layers are different. The DBR reflective film can reflect the light irradiated on each side of the color conversion film 12, thereby increasing the front light output of the light emitting diode package structure and improving the front brightness. Moreover, since the first reflective film 13 with a multi-layer stacked structure is coated on the side wall of the color conversion film 12, a sealed space can be formed with the first transparent protective layer 121 and the second transparent protective layer 123, and the color conversion particles in the sealed space can be sealed, which is particularly important for the color conversion particles dispersed in the color conversion layer 122, thereby greatly improving the stability of the color conversion film 12 and prolonging the service life of the light emitting diode package structure. Correspondingly, the film forming quality of the first reflective film 13 on the side wall of the color conversion film 12 is required to be high, which is one of the reasons why the applicant adopts the film forming method of first forming the surface and then grinding to remove the surface reflective film.

[0035] Referring to FIG. 1, in some embodiments of the present application, the thickness of the second transparent protective layer 123 is greater than the thickness of the first transparent protective layer 121.

[0036] In the light emitting diode packaging structure provided by the embodiment of the present application, the first transparent protective layer 121, the color conversion layer 122 and the second transparent protective layer 123 are sequentially stacked on the light emitting surface Q1 of the light emitting diode chip 11, that is, the light emitted by the light emitting diode chip 11 enters the color conversion layer 122 through the first transparent protective layer 121, and then is emitted to the outside of the light emitting diode packaging structure through the second transparent protective layer 123. After the color conversion of the color conversion particles in the color conversion layer 122, more large-angle excitation light is generated. The first reflective film 13 on the sidewall of the second transparent protective layer 123 can effectively limit the large-angle excitation light. Therefore, the smaller the thickness of the second transparent protective layer 123 is, the smaller the limiting effect of the first reflective film 13 on the large-angle excitation light is. In the present application, the thickness of the second transparent protective layer 123 is greater than the thickness of the first transparent protective layer 121, that is, the transparent protective layer without thickness loss is arranged at the outermost side of the light emitting diode packaging structure, so that the limiting effect of the first reflective film 13 on the large-angle excitation light is improved, and the light emitting diode packaging structure has smaller light emitting angle and higher front light intensity.

[0037] In some embodiments of the present application, the light emitting diode chip 11 is a flip LED chip, the shape of the light emitting diode chip 11 is a hexahedron or a similar hexahedron, and the light emitting diode chip 11 has five light emitting surfaces, which are the light emitting surface Q1 of the light emitting diode chip 11 and four side surfaces of the light emitting diode chip 11. That is, when the emitted light generated by the light emitting diode chip 11 is emitted from the four side surfaces of the light emitting diode chip 11, the front light loss will be caused, and the front light intensity of the light emitting diode packaging structure will be reduced. In order to solve the problem, in some embodiments of the present application, the light emitting diode packaging structure further comprises a second reflective film 14, which is arranged on the sidewall of the light emitting diode chip 11.

[0038] In the light emitting diode packaging structure provided by the embodiment of the present application, the second reflective film 14 arranged on the sidewall of the light emitting diode chip 11 can reduce the emitted light generated by the light emitting diode chip 11 from the side surface of the light emitting diode chip 11, so that more emitted light generated by the light emitting diode chip 11 is effectively utilized, and the front light intensity and brightness of the light emitting diode packaging structure are improved. Under the same power condition, the light emitting energy efficiency is improved, which is conducive to energy saving and environmental protection.

[0039] In some embodiments of the present application, the second reflective film 14 covers the sidewall of the light emitting diode chip 11 to increase the reflective area of the second reflective film 14 and increase the amount of light entering the color conversion film 12. Accordingly, in order to ensure the plating quality of the second reflective film 14 on the sidewall of the light emitting diode chip 11, a surface + side whole plating method is used to complete the plating process, and then a grinding method is used to remove the reflective film on the surface of the light emitting diode chip 11 to form the second reflective film 14 covering the sidewall of the light emitting diode chip 11.

[0040] In some embodiments of the present application, the second reflective film 14 is spaced apart from the first reflective film 13.

[0041] In the light emitting diode packaging structure provided by the embodiments of the present application, the second reflective film 14 is arranged on the sidewall of the light emitting diode chip 11, and the first reflective film 13 is arranged on the sidewall of the color conversion film 12. The reason why the second reflective film 14 is spaced apart from the first reflective film 13 is that the objects carrying the first reflective film 13 and the second reflective film 14 are different, which are the color conversion film 12 and the light emitting diode chip 11 respectively. The color conversion film 12 and the light emitting diode chip 11 are fixed by colloid, and the color conversion film 12 needs to be subjected to surface grinding treatment to remove the reflective film on the surface. The applicant has found through internal verification that if a continuous reflective film is formed on the sidewall of the light emitting diode chip 11 and the sidewall of the color conversion film 12 by one-time film forming, the grinding process in the process of removing the reflective film on the surface of the color conversion film 12 can easily cause the fixing of the colloid between the color conversion film 12 and the light emitting diode chip 11 to fail, and the relative position of the color conversion film 12 and the light emitting diode chip 11 deviates, which affects the light output effect and reduces the yield. In order to solve this problem, the embodiments of the present application form the first reflective film 13 and the second reflective film 14 in a discontinuous and spaced apart manner by forming the films on the sidewall of the light emitting diode chip 11 and the sidewall of the color conversion film 12 respectively, so as to ensure the connection stability and position matching between the color conversion film 12 and the light emitting diode chip 11, and further ensure the light output effect and the yield.

[0042] In some embodiments of the present application, the second reflective film 14 and the first reflective film 13 are made of the same material.

[0043] In the light emitting diode packaging structure provided by the embodiments of the present application, the second reflective film 14 and the first reflective film 13 are made of the same material, so the same film forming equipment can be used to prepare the first reflective film 13 and the second reflective film 14, thereby reducing the production cost.

[0044] In some embodiments of the present application, the light emitting diode chip 11 comprises a substrate layer 111, a surface of a side of the substrate layer 111 facing the color conversion film 12 is the light emitting surface Q1 of the light emitting diode chip 11, wherein the material of the substrate layer 111 is the same as the material of the first transparent protective layer 121 and the second transparent protective layer 123, and the thickness of the substrate layer 111 is less than the thickness of the first transparent protective layer 121.

[0045] In the light emitting diode package structure provided by the embodiments of the present application, as described above, the second reflective film 14 is arranged apart from the first reflective film 13, and the first reflective film 13 and the second reflective film 14 are discontinuous and arranged apart by forming films on the side wall of the light emitting diode chip 11 and on the side wall of the color conversion film 12. That is, the light emitting diode chip 11 and the color conversion film 12 both need to be subjected to surface grinding treatment to remove the reflective film on the surface of the light emitting diode chip 11 and the reflective film on the surface of the color conversion film 12.

[0046] As described above, the light emitting diode chip 11 and the color conversion film 12 both need to be subjected to surface grinding treatment to remove the reflective film on the surface of the light emitting diode chip 11 and the reflective film on the surface of the color conversion film 12, that is, after the reflective film is formed on the surface and the side of the light emitting diode chip 11 based on the surface of the substrate layer 111 as the film forming surface, the reflective film on the surface of the substrate layer 111 is removed by subsequent grinding process. Due to the existence of grinding error, at least part of the substrate layer 111 is removed by grinding. Therefore, when the material of the substrate layer 111 is the same as the material of the first transparent protective layer 121 and the second transparent protective layer 123, the grinding process parameters used for removing the reflective film on the surface of the light emitting diode chip 11 can be the same as the grinding process parameters used for removing the reflective film on the surface of the color conversion film 12, which is conducive to reducing the manufacturing cost and improving the production yield.

[0047] In addition, in the preparation process of the light emitting diode chip 11, taking a flip chip as an example, each independent light emitting diode chip 11 is formed by laser cutting and fragmentation process, which forms an uneven crater structure on the side wall of the substrate layer 111 of the light emitting diode chip 11. In order to avoid the adverse effect of the crater structure on the reflection effect of the second reflective film 14 on the side wall of the light emitting diode chip 11, the crater structure is removed by grinding, which also thins the thickness of the substrate layer 111. That is, the substrate layer 111 will undergo two thinning grinding processes, which will make the thickness of the substrate layer 111 less than the thickness of the first transparent protective layer 121 and the second transparent protective layer 123.

[0048] In some embodiments of the present application, the light emitting diode packaging structure further comprises an adhesive layer 15 connecting the base layer 111 and the first transparent protective layer 121, wherein the surface roughness of the side of the first transparent protective layer 121 facing the adhesive layer 15 is greater than the surface roughness of the side of the second transparent protective layer 123 facing away from the color conversion layer 122, and the thickness of the first transparent protective layer 121 is less than the thickness of the second transparent protective layer 123.

[0049] In the light emitting diode packaging structure provided by the embodiments of the present application, the adhesive layer 15 arranged between the base layer 111 and the first transparent protective layer 121 is used to adhere and fix the light emitting diode chip 11 and the color conversion film 12. In order to improve the adhesion effect of the adhesive layer 15 on the color conversion film 12, the surface roughness of the side of the first transparent protective layer 121 facing the adhesive layer 15 needs to be greater than a preset value, and the way to improve the surface roughness of the side of the first transparent protective layer 121 facing the adhesive layer 15 can be grinding.

[0050] As mentioned above, the first reflective film 13 with high plating quality can be formed on the side wall of the color conversion film 12 by the way of plating the surface of the first transparent protective layer 121 with a basic thickness and the side wall of the color conversion film 12 as a whole, and then grinding to remove the reflective film on the surface of the first transparent protective layer 121, and the grinding can also remove part of the thickness of the first transparent protective layer 121, so that the thickness of the first transparent protective layer 121 is less than the thickness of the second transparent protective layer 123, and thus the light emitting diode packaging structure has a smaller light emitting angle and a higher front light emitting intensity.

[0051] That is, by the way of plating the surface of the first transparent protective layer 121 with a basic thickness and the side wall of the color conversion film 12 as a whole, and then grinding to remove the reflective film on the surface of the first transparent protective layer 121, not only can the light emitting diode packaging structure have a smaller light emitting angle and a higher front light emitting intensity, but also by controlling the grinding process parameters, the surface roughness of the side of the first transparent protective layer 121 facing the adhesive layer 15 can be made greater than the surface roughness of the side of the second transparent protective layer 123 facing away from the color conversion layer 122, thereby improving the adhesion effect of the adhesive layer 15 on the color conversion film 12 and improving the structural stability and product yield.

[0052] In some embodiments of the present application, the adhesive layer 15 does not include color conversion particles. Since the adhesive layer 15 does not include color conversion particles, the adhesion of the adhesive layer 15 can be improved, and without considering the material selection limitations caused by the introduction of color conversion particles, the adhesive layer 15 can be applied to materials with higher temperature resistance, thereby improving the temperature resistance of the light emitting diode packaging structure.

[0053] In some embodiments of the present application, the color conversion layer 122 includes fluorescent powder and does not include silica gel, and the fluorescent powder is sintered and fixed with the first transparent protective layer 121 and the second transparent protective layer 123.

[0054] In the light emitting diode packaging structure provided by the embodiments of the present application, the color conversion layer 122 includes fluorescent powder and does not include silica gel, that is, the color conversion particles in the color conversion layer 122 are fluorescent powder, and the fluorescent powder in the color conversion layer 122 is fixed between the first transparent protective layer 121 and the second transparent protective layer 123 by sintering, instead of a conventional fluorescent glue layer, and compared with the distribution form of the fluorescent powder in the related art, the distribution form of the fluorescent powder is more concentrated, which is more conducive to the control of the light emitting angle.

[0055] In some embodiments of the present application, the color conversion layer 122 only includes fluorescent powder, and gaps exist between adjacent fluorescent powders, and the fluorescent powder is sealed in the sealed space formed by the first reflective film 13, the first transparent protective layer 121 and the second transparent protective layer 123.

[0056] In some embodiments of the present application, the thickness of the color conversion layer 122 is less than or equal to 60 microns, and the difference between the maximum particle size and the minimum particle size of the fluorescent powder in the color conversion layer 122 is less than 40 microns.

[0057] In the light emitting diode packaging structure provided by the embodiments of the present application, since the color conversion layer 122 does not include silica gel, the thickness of the color conversion layer 122 can be further reduced to less than 60 microns. In addition, in order to ensure the quality of sintering fixation, the difference between the maximum particle size and the minimum particle size of the fluorescent powder in the color conversion layer 122 is controlled and specifically controlled in the range of 0 to 40 microns.

[0058] FIG. 3 is a schematic cross-sectional view of a light emitting diode chip according to some embodiments of the present application. In some embodiments of the present application, the light emitting diode chip 11 includes a chip body 112 and a substrate layer 111, and the chip body 112 is disposed on the side of the substrate layer 111 facing away from the color conversion film 12. Optionally, in the direction of the substrate layer 111 facing away from the color conversion film 12, the chip body 112 includes a buffer layer X1, a first type semiconductor layer X2, a light emitting layer X3, a second type semiconductor layer X4, and an electrode layer X5, which are sequentially stacked, the first type semiconductor layer X2 is one of an N-type semiconductor layer or a P-type semiconductor layer, the second type semiconductor layer X4 is the other of a P-type semiconductor layer or an N-type semiconductor layer, the electrode layer X5 includes a first electrode X51 and a second electrode X52, the first electrode X51 is electrically connected to the first type semiconductor layer X2, and the second electrode X52 is electrically connected to the second type semiconductor layer X4. Optionally, the chip body 112 can further include a current spreading layer X6, an ohmic contact layer X7, and a current blocking layer X8 disposed on the side of the second type semiconductor layer X4 facing away from the substrate layer 111. It should be noted that the above is only an example of the structure of the chip body 112, and the present application does not limit the specific structure of the chip body 112.

[0059] In some embodiments of the present application, the materials of the first transparent protective layer 121 and the second transparent protective layer 123 include, but are not limited to, sapphire, silicon carbide, glass, and the like.

[0060] In some embodiments of the present application, the packaging form of the light emitting diode packaging structure is CSP, but the present application does not limit the packaging form of the light emitting diode packaging structure.

[0061] In a second aspect, some embodiments of the present application provide a method for manufacturing a light emitting diode packaging structure, which includes the following steps: disposing a light emitting diode chip and a color conversion film on a supporting table coated with a UV debonding film on one surface, wherein the color conversion film includes a first transparent protective layer, a color conversion layer, and a second transparent protective layer; depositing a first reflective film on one surface and each side wall of the color conversion film and depositing a second reflective film on one surface and each side wall of the light emitting diode chip; removing the first reflective film on the surface of the color conversion film by grinding and removing the second reflective film on the surface of the light emitting diode chip by grinding; forming a bonding layer on the light emitting surface of the light emitting diode chip, disposing the color conversion film on the bonding layer, and performing a baking process to fix the color conversion film on the light emitting surface of the light emitting diode chip.

[0062] The preparation method of the light emitting diode packaging structure provided in the embodiments of the present application can fix the light emitting diode chip and the color conversion film well by placing the light emitting diode chip and the color conversion film on the supporting table coated with the UV debonding film on one surface, thereby greatly improving the fixing effect compared with the conventional adhesive film fixing, so as to avoid the position deviation of the light emitting diode chip and the color conversion film in the subsequent grinding process. After the grinding is completed, the UV light can be used to treat the UV debonding film, so as to facilitate the peeling of the light emitting diode chip and the color conversion film, and the peeling yield is good.

[0063] In the preparation method of the light emitting diode packaging structure provided in the embodiments of the present application, the first reflective film is deposited on one surface and each side wall of the color conversion film, so as to improve the film forming quality and stability of the first reflective film formed on the side wall of the color conversion film. The second reflective film is deposited on one surface and each side wall of the light emitting diode chip, so as to improve the film forming quality and stability of the second reflective film formed on the side wall of the light emitting diode chip. Optionally, the color conversion film and the light emitting diode chip can be placed in the film forming equipment at the same time for film forming, that is, the film forming process of the first reflective film is synchronized with the film forming process of the second reflective film, so as to reduce the process steps and the production cost. However, in other embodiments of the present application, the film forming process of the first reflective film and the film forming process of the second reflective film can be performed sequentially.

[0064] In the preparation method of the light emitting diode packaging structure provided in the embodiments of the present application, the first reflective film on the surface of the color conversion film is removed by grinding, so as to keep the first reflective film complete on the side wall of the color conversion film, so that the first reflective film covers the side wall of the color conversion film, thereby reducing the light emitting angle of the subsequently formed light emitting diode packaging structure and improving the front light emitting intensity. The second reflective film on the surface of the light emitting diode chip is removed by grinding, so as to keep the second reflective film complete on the side wall of the light emitting diode chip, so that the second reflective film covers the side wall of the light emitting diode chip, thereby improving the problem of light leakage caused by the side light emitting of the light emitting diode chip, effectively increasing the front light emitting amount, and improving the front light emitting efficiency and brightness. In addition, the outer layer of the color conversion layer in the color conversion film is provided with the first transparent protective layer 121 and the second transparent protective layer 123, so as to protect the color conversion layer and avoid the color conversion particles in the color conversion layer being removed by grinding in the grinding process, thereby ensuring the color rendering accuracy of the light emitting diode packaging structure and better controlling the color temperature range to improve the product yield.

[0065] The preparation method of the light emitting diode packaging structure provided by the embodiments of the present application can form a bonding layer on the light emitting surface of the light emitting diode chip, and set the color conversion film on the bonding layer and perform baking treatment, so as to fix and connect the light emitting diode chip and the color conversion film by using the bonding layer, and further form a light emitting diode packaging structure.

[0066] FIG. 4 is a flowchart of a preparation method of a light emitting diode packaging structure according to some embodiments of the present application. As shown in FIG. 4, in some embodiments of the present application, the preparation method of the light emitting diode packaging structure includes steps S10, S20, S30, S40 and S50.

[0067] FIG. 5a is a schematic diagram corresponding to step S10 according to some embodiments of the present application. As shown in FIGS. 4 and 5a, step S10 includes grinding the base layer 111 in the light emitting diode chip 11 to remove the bump structure Z1 in the base layer 111.

[0068] FIG. 5b is a schematic diagram corresponding to step S20 according to some embodiments of the present application. As shown in FIGS. 4 and 5b, step S20 includes setting the light emitting diode chip 11 and the color conversion film 12 on a carrier table 16 coated with a UV debonding film 17 on a surface, wherein the color conversion film 12 includes a first transparent protective layer 121, a color conversion layer 122 and a second transparent protective layer 123, and the first transparent protective layer 121 is arranged on the side of the second transparent protective layer 123 away from the carrier table 16.

[0069] FIG. 5c is a schematic diagram corresponding to step S30 according to some embodiments of the present application. As shown in FIGS. 4 and 5c, step S30 includes depositing a first reflective film 13 on one surface and each side wall of the color conversion film 12, and depositing a second reflective film 14 on one surface and each side wall of the light emitting diode chip 11. Optionally, the one surface of the light emitting diode chip 11 can be the light emitting surface Q1 of the light emitting diode chip 11, or the back light surface of the light emitting diode chip 11. FIG. 5c shows that the second reflective film 14 is deposited on the back light surface and each side wall of the light emitting diode chip 11.

[0070] FIG. 5d is a schematic diagram corresponding to step S30 according to some embodiments of the present application. As shown in FIGS. 4 and 5d, step S40 includes removing the first reflective film 13 on the surface of the color conversion film 12 by grinding, and removing the second reflective film 14 on the surface of the light emitting diode chip 11 by grinding.

[0071] Figure 5e is a schematic view corresponding to step S30 according to some embodiments of the present application. As shown in Figure 4 and Figure 5e, step S50 comprises forming an adhesive layer 15 on the light emitting surface Q1 of the light emitting diode chip 11, and disposing the color conversion film 12 on the adhesive layer 15, and performing a baking process to fix the color conversion film 12 on the light emitting surface Q1 of the light emitting diode chip 11.

[0072] The preparation method of the light emitting diode packaging structure provided by the embodiments of the present application comprises the process of forming the independent light emitting diode chip 11, which needs to go through the processes of laser cutting and chipping. This process will form uneven crater structures Z1 on the sidewalls of the substrate layer 111 of the light emitting diode chip 11. In order to avoid the adverse effects of the crater structures Z1 on the reflection effect of the second reflective film 14 on the sidewalls of the light emitting diode chip 11, the crater structures Z1 are removed by grinding. This also means that the grinding equipment for removing the crater structures Z1 can also be used in the subsequent reflective film grinding and removing process, which can effectively reduce the equipment cost. In addition, since the process of grinding and removing the crater structures Z1 has been performed on the light emitting diode chip 11 before the second reflective film 14 is deposited and formed on one surface and each sidewall of the light emitting diode chip 11, the film forming quality and stability of the second reflective film 14 on the sidewalls of the light emitting diode chip 11 can be effectively improved.

[0073] Figure 6 is a flowchart of a preparation method of a light emitting diode packaging structure according to some embodiments of the present application. As shown in Figure 6, in some embodiments of the present application, the preparation method of the light emitting diode packaging structure comprises step M10, step M20, step M30, and step M40.

[0074] Figure 7a is a schematic view corresponding to step M10 according to some embodiments of the present application. As shown in Figure 6 and Figure 7a, step M10 comprises disposing the light emitting diode chip 11 and the color conversion film 12 on a carrier table 16 coated with a UV debonding film 17 on a surface, wherein the color conversion film 12 comprises a first transparent protective layer 121, a color conversion layer 122, and a second transparent protective layer 123.

[0075] Figure 7b is a schematic view corresponding to step M20 according to some embodiments of the present application. As shown in Figure 6 and Figure 7b, step M20 comprises depositing and forming a first reflective film 13 on one surface and each sidewall of the color conversion film 12, and depositing and forming a second reflective film 14 on one surface and each sidewall of the light emitting diode chip 11, wherein the one surface of the light emitting diode chip 11 is the surface of the substrate layer 111 away from the chip body 112.

[0076] FIG. 7c is a schematic view corresponding to step M30 according to some embodiments of the present application. As shown in FIG. 6 and FIG. 7c, step M30 includes removing the first reflective film 13 on the surface of the color conversion film 12 by grinding, removing the second reflective film 14 on the surface of the light emitting diode chip 11 by grinding, and removing the crater structure Z1 in the base layer 111 of the light emitting diode chip 11 by grinding.

[0077] FIG. 7d is a schematic view corresponding to step M30 according to some embodiments of the present application. As shown in FIG. 6 and FIG. 7d, step M40 includes forming an adhesive layer 15 on the light emitting surface Q1 of the light emitting diode chip 11, and disposing the color conversion film 12 on the adhesive layer 15, and performing a baking process to fix the color conversion film 12 on the light emitting surface Q1 of the light emitting diode chip 11.

[0078] In the method for manufacturing the light emitting diode packaging structure according to the embodiments of the present application, the second reflective film 14 on the surface of the light emitting diode chip 11 and the crater structure Z1 in the base layer 111 of the light emitting diode chip 11 can be removed by one grinding process, thereby reducing the process steps and lowering the production cost. In addition, in order to ensure the film forming quality and stability of the second reflective film 14 on the sidewall of the light emitting diode chip 11, the light emitting diode chip 11 can be further ground, i.e., the grinding depth is further increased based on the depth of the crater structure Z1.

[0079] In summary, the present application provides a light emitting diode packaging structure and a method for manufacturing the same. The light emitting diode packaging structure includes a light emitting diode chip, a color conversion film, and a first reflective film. The color conversion film is disposed on the light emitting surface of the light emitting diode chip, and the first reflective film is disposed on the sidewall of the color conversion film. The color conversion film includes a first transparent protective layer, a color conversion layer, and a second transparent protective layer which are sequentially stacked on the light emitting surface of the light emitting diode chip. In the light emitting diode packaging structure according to the present application, the first reflective film disposed on the sidewall of the color conversion film can reduce the light emitting angle, increase the front light emission, and because the color conversion layer is protected by the transparent protective layer on the outside of the color conversion layer during the grinding process, the color temperature interval of the light emitting diode packaging structure can be within the normal range, thereby improving the production yield of the light emitting diode packaging structure.

[0080] The above has carried on the detailed introduction to the light emitting diode packaging structure and the preparation method thereof provided by the embodiment of the application, the principle and the implementation mode of the application are described by applying specific examples, the above embodiment is only used for helping understanding the method of the application and its core idea; meanwhile, for the person skilled in the art, according to the idea of the application, the specific implementation mode and the application range will have the change, and the above is described, the content of the specification should not be understood as the limitation of the application.

Claims

1. A light emitting diode package structure, wherein, The light emitting diode packaging structure comprises: a light emitting diode chip; a color conversion film arranged on a light emitting surface of the light emitting diode chip; a first reflective film arranged on a side wall of the color conversion film; wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer arranged in sequence on the light emitting surface of the light emitting diode chip.

2. The light emitting diode package structure of claim 1, wherein, The first reflective film covers the side wall of the color conversion film, and the thickness of the second transparent protective layer is different from the thickness of the first transparent protective layer.

3. The light emitting diode package structure of claim 2, wherein, The thickness of the second transparent protective layer is greater than the thickness of the first transparent protective layer.

4. The light emitting diode package structure of claim 2, wherein, The light emitting diode packaging structure further comprises a second reflective film arranged on a side wall of the light emitting diode chip, and the second reflective film is arranged spaced apart from the first reflective film.

5. The light emitting diode package structure of claim 4, wherein, The second reflective film and the first reflective film are made of the same material.

6. The light emitting diode package structure of claim 4, wherein, The light emitting diode chip comprises a base layer, a surface of one side of the base layer facing the color conversion film being a light emitting surface of the light emitting diode chip, wherein the material of the base layer is the same as the material of the first transparent protective layer and the second transparent protective layer, and the thickness of the base layer is less than the thickness of the first transparent protective layer and the second transparent protective layer.

7. The light emitting diode package structure of claim 6, wherein, The light emitting diode packaging structure further comprises a bonding layer connecting the base layer and the first transparent protective layer, wherein the surface roughness of one side of the first transparent protective layer facing the bonding layer is greater than the surface roughness of one side of the second transparent protective layer away from the color conversion layer, and the thickness of the first transparent protective layer is less than the thickness of the second transparent protective layer.

8. The light emitting diode package structure of claim 2, wherein, The color conversion layer comprises fluorescent powder and does not comprise silica gel, and the fluorescent powder is sintered and fixed with the first transparent protective layer and the second transparent protective layer.

9. The light emitting diode package structure of claim 8, wherein, The thickness of the color conversion layer is less than or equal to 60 microns, and the difference between the maximum particle size and the minimum particle size of the fluorescent powder in the color conversion layer is less than 40 microns.

10. The light emitting diode package structure of claim 1, wherein, The first reflective film is a DBR reflective film.

11. The light emitting diode package structure of claim 1, wherein, The color conversion layer only comprises fluorescent powder, and has gaps between adjacent fluorescent powders, and the fluorescent powder is sealed in a sealed space formed by the first reflective film and the first transparent protective layer and the second transparent protective layer.

12. The light emitting diode package structure of claim 1, wherein, The light emitting diode chip is a flip chip.

13. The light emitting diode package structure of claim 1, wherein, The first reflective film covers the side wall of the color conversion film; the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer arranged in sequence on the light emitting surface of the light emitting diode chip; the light emitting diode packaging structure further comprises a bonding layer connecting the light emitting surface of the light emitting diode chip and the first transparent protective layer, wherein the surface roughness of one side of the first transparent protective layer facing the bonding layer is greater than the surface roughness of one side of the second transparent protective layer away from the color conversion layer, and the thickness of the first transparent protective layer is less than the thickness of the second transparent protective layer.

14. The light emitting diode package structure of claim 13, wherein, The light emitting diode packaging structure further comprises a second reflective film arranged on a side wall of the light emitting diode chip, and the second reflective film is arranged spaced apart from the first reflective film.

15. The light emitting diode package structure of claim 14, wherein, The second reflective film and the first reflective film are made of the same material.

16. The light emitting diode package structure of claim 14, wherein, The light-emitting diode chip comprises a substrate layer, a surface of a side of the substrate layer facing the color conversion film is a light-emitting surface of the light-emitting diode chip, wherein the material of the substrate layer is the same as that of the first transparent protective layer and the second transparent protective layer, and the thickness of the substrate layer is smaller than that of the first transparent protective layer and the second transparent protective layer.

17. The light emitting diode package structure of claim 13, wherein, The color conversion layer comprises fluorescent powder and does not comprise silica gel, and the fluorescent powder is sintered and fixed with the first transparent protective layer and the second transparent protective layer.

18. The light emitting diode package structure of claim 17, wherein, The thickness of the color conversion layer is less than or equal to 60 microns, and the difference between the maximum particle size and the minimum particle size of the fluorescent powder in the color conversion layer is less than 40 microns.

19. A method of fabricating a light emitting diode package structure, wherein, The preparation method of the light-emitting diode packaging structure comprises the following steps: placing the light-emitting diode chip and the color conversion film on a supporting table coated with a UV debonding film on a surface, wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer; depositing a first reflective film on one surface and each side wall of the color conversion film and depositing a second reflective film on one surface and each side wall of the light-emitting diode chip; removing the first reflective film on the surface of the color conversion film by grinding and removing the second reflective film on the surface of the light-emitting diode chip by grinding; forming a bonding layer on the light-emitting surface of the light-emitting diode chip, placing the color conversion film on the bonding layer, and performing baking treatment to fix the color conversion film on the light-emitting surface of the light-emitting diode chip.

20. The method for preparing a light-emitting diode packaging structure according to claim 19, wherein, after the step of placing the light-emitting diode chip and the color conversion film on a supporting table coated with a UV debonding film on a surface, depositing a first reflective film on one surface and each side wall of the color conversion film and depositing a second reflective film on one surface and each side wall of the light-emitting diode chip, wherein the first reflective film covers the side walls of the color conversion film, and one surface of the color conversion film is a surface of a side of the first transparent protective layer facing away from the color conversion layer; removing the first reflective film and at least part of the thickness of the first transparent protective layer on the surface of the color conversion film by grinding, so that the thickness of the first transparent protective layer is smaller than that of the second transparent protective layer, and the surface roughness of the side of the first transparent protective layer facing away from the color conversion layer is greater than that of the side of the second transparent protective layer facing away from the color conversion layer; and removing the second reflective film on the surface of the light-emitting diode chip by grinding; forming a bonding layer on the light-emitting surface of the light-emitting diode chip, placing the color conversion film on the bonding layer, and performing baking treatment to fix the color conversion film on the light-emitting surface of the light-emitting diode chip, wherein the bonding layer connects the light-emitting surface of the light-emitting diode chip and the first transparent protective layer, and the first transparent protective layer, the color conversion layer and the second transparent protective layer are sequentially arranged on the light-emitting surface of the light-emitting diode chip.

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