A light emitting diode packaging structure and preparation method thereof

Abstract

The present application provides a light-emitting diode packaging structure and a preparation method thereof, wherein the light-emitting diode packaging structure includes a light-emitting diode chip, a color conversion film and a first reflective film, wherein the color conversion film is arranged on the light-emitting surface of the light-emitting diode chip, and the first reflective film is arranged on the side wall of the color conversion film; wherein 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 provided by the present application, the first reflective film arranged on the side wall of the color conversion film can reduce the light-emitting angle and increase the front light emission, and since a transparent protective layer is arranged on the outer side of the color conversion layer, the color conversion layer can be protected during the grinding process, so that the color temperature range of the light-emitting diode packaging structure can be within a normal range, thereby improving the production yield of the light-emitting diode packaging structure.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a light emitting diode packaging structure and a preparation method thereof. Background Art

[0002] Light Emitting Diode (LED) has the advantages of small size, long service life, energy saving and environmental protection, fast response speed and durability. It is widely used in automobiles, indoor lighting, traffic lights, display devices and other fields. It is an ideal light source to replace traditional light sources. The light emitting diode packaging structure usually includes an LED chip and a color conversion layer. The LED chip can generate basic light with a specific wavelength. The color conversion particles in the color conversion layer can absorb the basic light with a 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 packaging structure. The light emitting diode packaging structure can be roughly divided into: direct plug-in packaging, surface mount (SMD) packaging, chip on board (COB) packaging and chip scale packaging (CSP) according to the packaging form. CSP has emerged in recent years based on the development of flip-chip LED chip technology. It has the advantages of small packaging volume and large effective light emitting area, and has broad market application prospects.

[0003] Taking the CSP LED packaging structure using flip-chip LED chips as an example, the front and side of the conventional CSP LED packaging structure emit light, which can be understood as five-sided light emission. This leads to the problem that the CSP LED packaging structure has a large light emission angle and a weak front light emission intensity, making it difficult to be used in lighting and display products that have higher precision requirements for the light emission angle and strong requirements for the front light emission intensity. In order to improve this problem, the applicant adopted the method of coating the side wall of the color conversion layer with a reflective film in its internal research and development to reduce the light emission angle and increase the front light emission, which makes the side wall coating quality a key factor affecting the light emission angle and the front light emission intensity of the CSP LED packaging structure. Furthermore, the applicant found in its internal research and development that in order to improve the side wall coating quality while ensuring the yield, it is necessary to complete the coating process by first coating the surface + side as a whole, and then remove the reflective film on the surface by grinding. The grinding error in the grinding process is inevitable, which leads to at least part of the color conversion layer being removed in the process of removing the reflective film on the front of the color conversion layer by grinding.

[0004] Based on the above internal research, the applicant found that the current color conversion layer is usually a fluorescent film or a ceramic glass fluorescent sheet. The fluorescent film is formed by uniformly mixing and curing the fluorescent powder in the transparent adhesive layer, and the ceramic glass fluorescent sheet is formed by sintering the fluorescent powder and the ceramic glass material together, which makes the fluorescent powder in the color conversion layer dispersed. When at least part of the color conversion layer is ground and removed, there will be problems such as loss of fluorescent powder in local areas and deterioration of the morphology of the light-emitting surface formed by grinding, which affect the color temperature range and product yield. This problem needs to be solved urgently. Summary of the invention

[0005] The present application provides a light-emitting diode packaging structure and a preparation method thereof, which can effectively solve the problem of the light-emitting diode packaging structure in the related art that it is difficult to reduce the light output angle, increase the front light output brightness, and take into account the color temperature range and yield.

[0006] In a first aspect, the present application provides a light emitting diode package structure, the light emitting diode package structure comprising:

[0007] Light emitting diode chips;

[0008] A color conversion film is arranged on the light emitting surface of the light emitting diode chip;

[0009] A first reflective film, disposed on a side wall of the color conversion film;

[0010] 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.

[0011] Optionally, 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.

[0012] Optionally, the thickness of the second transparent protective layer is greater than the thickness of the first transparent protective layer.

[0013] Optionally, the light-emitting diode packaging structure further includes a second reflective film, wherein the second reflective film is disposed on a side wall of the light-emitting diode chip, and the second reflective film is spaced apart from the first reflective film.

[0014] Optionally, the second reflective film and the first reflective film are made of the same material.

[0015] Optionally, the light-emitting diode chip includes a base layer, and the surface of the base layer facing the color conversion film is the light-emitting surface of the light-emitting diode chip, wherein the material of the base layer is the same as that 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.

[0016] Optionally, the light-emitting diode packaging structure also includes a bonding layer, which connects the base layer and the first transparent protective layer, wherein the surface roughness of the first transparent protective layer facing the bonding layer is greater than the surface roughness of the second transparent protective layer facing 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.

[0017] Optionally, the color conversion layer includes fluorescent powder but does not include silica gel, and the fluorescent powder is sintered and fixed to the first transparent protective layer and the second transparent protective layer.

[0018] Optionally, the thickness of the color conversion layer is less than or equal to 60 micrometers, and the difference between the maximum particle size and the minimum particle size of the phosphor in the color conversion layer is less than 40 micrometers.

[0019] In a second aspect, the present application provides a method for preparing a light emitting diode package structure, the method for preparing a light emitting diode package structure comprising the following steps:

[0020] The light-emitting diode chip and the color conversion film are arranged on a carrier with a UV debonding film coated on the surface, wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer;

[0021] 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;

[0022] 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;

[0023] An adhesive layer is formed on the light emitting surface of the light emitting diode chip, and the color conversion film is arranged on the adhesive layer, and a baking treatment is performed to fix the color conversion film on the light emitting surface of the light emitting diode chip.

[0024] The present application provides a light-emitting diode packaging structure and a preparation method thereof, wherein the light-emitting diode packaging structure includes a light-emitting diode chip, a color conversion film and a first reflective film, wherein the color conversion film is arranged on the light-emitting surface of the light-emitting diode chip, and the first reflective film is arranged on the side wall of the color conversion film; wherein 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 provided by the present application, the first reflective film arranged on the side wall of the color conversion film can reduce the light-emitting angle and increase the front light emission, and since a transparent protective layer is arranged on the outer side of the color conversion layer, the color conversion layer can be protected during the grinding process, so that the color temperature range of the light-emitting diode packaging structure can be within a normal range, thereby improving the production yield of the light-emitting diode packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0026] Figure 1 A cross-sectional schematic diagram of a light emitting diode packaging structure provided in some embodiments of the present application.

[0027] Figure 2 A cross-sectional schematic diagram of another light emitting diode packaging structure provided for some embodiments of the present application.

[0028] Figure 3 A schematic cross-sectional view of a light emitting diode chip provided in some embodiments of the present application.

[0029] Figure 4 A schematic flow chart of a method for preparing a light emitting diode packaging structure provided in some embodiments of the present application.

[0030] Figure 5a to Figure 5e Schematic diagrams corresponding to steps S10 to S50 provided in some embodiments of the present application.

[0031] Figure 6 A schematic flow chart of another method for preparing a light emitting diode packaging structure provided in some embodiments of the present application.

[0032] Figures 7a to 7d Schematic diagrams corresponding to steps M10 to M40 provided in some embodiments of the present application.

[0033] Description of reference numerals:

[0034] Light-emitting diode chip 11; light-emitting surface Q1 of the light-emitting diode chip; substrate layer 111; explosion point 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; carrier platform 16; UV debonding film 17. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0036] The terms "first" and "second" in this document are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts 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 repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0039] Figure 1 A cross-sectional schematic diagram of a light emitting diode packaging structure provided in some embodiments of the present application; Figure 2 A cross-sectional schematic diagram of another light emitting diode packaging structure provided in some embodiments of the present application. Figure 1 and Figure 2 As shown, an embodiment of 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 arranged on the light-emitting surface Q1 of the light-emitting diode chip 11; the first reflective film 13 is arranged 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 sequentially stacked on the light-emitting surface Q1 of the light-emitting diode chip 11.

[0040] In the light-emitting diode packaging structure provided by the present application, the first reflective film 13 arranged on the side wall of the color conversion film 12 can reduce the light output angle and increase the front light output. In addition, since a transparent protective layer is arranged on the outer side of the color conversion layer 122, the color conversion layer 122 can be protected by the transparent protective layer during the grinding process, thereby 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 making the color temperature range of the light-emitting diode packaging structure within a 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.

[0041] In addition, since the color conversion layer 122 is sandwiched between two transparent protective layers, compared with a structure in which the color conversion particles are uniformly dispersed in the color conversion film 12, more light excited 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 light emitting angle narrowing effect of the light emitting diode package structure. For example, after actual testing, the actual light emitting angle of the light emitting diode package structure provided by the present application can reach below 140°, or even below 120°.

[0042] In some embodiments of the present application, the LED chip 11 can generate a basic light of a specific wavelength, and the color conversion film 12 disposed on the light-emitting surface Q1 of the LED chip 11 can absorb the basic light of a specific wavelength and convert it into light of other wavelengths, thereby realizing a color conversion function. Exemplarily, the basic light can be a blue light of a blue light band, and the color conversion particles in the color conversion film 12 disposed on the light-emitting surface Q1 of the LED chip 11 can be a yellow phosphor, which can absorb part of the blue light and convert it into yellow light of a yellow light band, thereby enabling the LED package structure to form white light and emit it; Exemplarily, the basic light can be a blue light of a blue light band, and the color conversion particles in the color conversion film 12 disposed on the light-emitting surface Q1 of the LED chip 11 can include red quantum dots and green quantum dots, and the red quantum dots can absorb part of the blue light and convert it into red light of a red light band, and the green quantum dots can absorb part of the blue light and convert it into green light of a green light band, thereby enabling the LED package structure to form white light and emit it. Of course, in other embodiments of the present application, the light-emitting diode chip 11 may also be other chips besides the blue light LED chip, and the color conversion particles may also be other color conversion materials besides yellow phosphor and red and green quantum dots.

[0043] In some embodiments of the present application, the color conversion film 12 has a certain thickness and is in the shape of a hexahedron or a quasi-hexahedron. The color conversion film 12 includes a first surface, a second surface, and four side surfaces located between the first surface and the second surface, the first surface being located between the light emitting surface Q1 of the light emitting diode chip 11 and the second surface, and the four side surfaces are the 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. Since the first reflective film 13 is provided on the side wall of the color conversion film 12, the light can be reflected by the first reflective film 13, thereby increasing the amount of light emitted from the second surface, thereby reducing the light emitting angle of the light emitting diode package structure, increasing the amount of light emitted from the front of the light emitting diode package structure, and increasing the front brightness.

[0044] In some embodiments of the present application, the first reflective film 13 covers the sidewall 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 .

[0045] In the light-emitting diode packaging structure provided in the embodiment of the present application, the first reflective film 13 is provided on the side wall of the color conversion film 12. However, the applicant has found in the internal research and development that it is difficult to realize coating only on the side wall of the color conversion film 12 with the existing process while ensuring the quality of the side wall coating. It is necessary to complete the coating process by first coating the surface and then coating the side as a whole to improve the quality of the side wall coating so that the first reflective film 13 covers the side wall of the color conversion film 12. Furthermore, the reflective film on the surface of the color conversion film 12 will affect the light emission. Therefore, it is also necessary to remove the reflective film on the surface of the color conversion film 12. However, the film removal method such as peeling will directly deteriorate the coating quality on 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. After comprehensive evaluation and testing, the applicant found that the method of grinding and removing 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 coating quality of the reflective film on the side wall of the color conversion film 12, thereby achieving the technical effect that the side wall of the color conversion film 12 is covered by the first reflective film 13, thereby ensuring that the light output angle can be effectively narrowed and the brightness of the front light output is effectively improved.

[0046] The applicant further discovered that in order to completely remove the reflective film on the surface of the color conversion film 12, a certain grinding error needs to be introduced, or in other words, at least a portion of the protective layer needs to be ground off. Figure 1 As shown, when a process is adopted in which a film is firstly formed on the surface of the first transparent protective layer 121 having a basic thickness and the side wall of the color conversion film 12 as a whole, and then the reflective film on the surface of the first transparent protective layer 121 is removed by grinding, a part of the first transparent protective layer 121 will be ground away, 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, so that the thickness of the first transparent protective layer 121 is 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. Figure 2As shown, when a process is adopted in which a second transparent protective layer 123 having a basic thickness is firstly coated on the surface and the side wall of the color conversion film 12, and then the reflective film on the surface of the second transparent protective layer 123 is removed by grinding, a part of the second transparent protective layer 123 will be ground away, that is, the second transparent protective layer 123 will produce 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 produce a thickness loss and still has the basic thickness, so that the thickness of the second transparent protective layer 123 is 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.

[0047] Therefore, the present application enables the first reflective film 13 to cover the side wall of the color conversion film 12, thereby achieving the technical effect that the light output angle is effectively narrowed and the brightness of the front light output is effectively improved. In addition, although the realization of the first reflective film 13 covering the side wall of the color conversion film 12 depends on the process of first forming the surface + side surface as a whole, and then grinding and removing the reflective film on the surface of the color conversion film 12, the present application uses a sandwich structure color conversion film, and by sacrificing at least part of the protective layer (the first transparent protective layer 121 or the second transparent protective layer 123), the thickness of the second transparent protective layer 123 is different from the thickness of the first transparent protective layer 121, thereby ensuring the performance stability of the color conversion layer 122 in the color conversion film 12, and thus being able to better control the color temperature range of the light-emitting diode packaging structure, so that the color rendering of the light-emitting diode packaging structure is more accurate and the production yield is higher.

[0048] In some embodiments of the present application, the first reflective film 13 is a metal reflective film, such as a silver reflective film, so as to utilize the high reflectivity of the silver reflective film at multiple angles to reflect the light irradiated on the four sides of the color conversion film 12, thereby increasing the front light output of the light-emitting diode packaging structure and improving the front brightness.

[0049] In some embodiments of the present application, the first reflective film 13 is a DBR reflective film, and the first reflective film 13 includes a plurality of first oxide reflective layers and a plurality of second oxide reflective layers stacked, and the first oxide reflective layer and the second oxide reflective layer have different refractive indices. The DBR reflective film can reflect the light irradiated on each of the side surfaces of the color conversion film 12, thereby increasing the amount of light emitted from the front of the light-emitting diode package structure and increasing the front brightness. Moreover, it is critical that since the first reflective film 13 with a multi-layer stacked structure is coated on the side wall of the color conversion film 12, it can form a closed space with the first transparent protective layer 121 and the second transparent protective layer 123, and thus can seal the color conversion particles in the closed space, which is particularly important for the color conversion particles dispersedly arranged in the color conversion layer 122, and can greatly improve the stability of the color conversion film 12 and extend the service life of the light-emitting diode package structure. Correspondingly, this puts forward higher requirements on the film forming quality of the first reflective film 13 on the side wall of the color conversion film 12, which is one of the reasons why the applicant adopts the overall film forming of the surface + side surface first, and then grinding to remove the surface reflective film.

[0050] Reference Figure 1 As shown, 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 .

[0051] In the LED packaging structure provided in 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 LED chip 11, that is, the light emitted by the LED chip 11 is incident into the color conversion layer 122 via the first transparent protective layer 121, and then emitted to the outside of the LED packaging structure via the second transparent protective layer 123. After the light emitted by the LED chip 11 is converted by the color conversion particles in the color conversion layer 122, more large-angle excitation light will be generated. The first reflective film 13 on the side wall 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, the smaller the limiting effect of the first reflective film 13 on the large-angle excitation light. The present application makes the thickness of the second transparent protective layer 123 greater than the thickness of the first transparent protective layer 121, that is, by arranging a transparent protective layer without thickness loss on the outermost side of the light-emitting diode packaging structure, it is possible to improve the limiting effect of the first reflective film 13 on large-angle excitation light, so that the light-emitting diode packaging structure has a smaller light output angle and a higher front light output intensity.

[0052] In some embodiments of the present application, the light-emitting diode chip 11 is a flip-chip LED chip, and the shape of the light-emitting diode chip 11 is a hexahedron or a quasi-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 the 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, it will cause front light loss, reducing the front light intensity of the light-emitting diode package structure. In order to improve this problem, in some embodiments of the present application, the light-emitting diode package structure also includes a second reflective film 14, and the second reflective film 14 is arranged on the side wall of the light-emitting diode chip 11.

[0053] In the LED packaging structure provided in the embodiment of the present application, the second reflective film 14 arranged on the side wall of the LED chip 11 can reduce the outgoing light generated by the LED chip 11 from being emitted from the side of the LED chip 11, so that more outgoing light generated by the LED chip 11 can be effectively utilized, thereby improving the front light output intensity and brightness of the LED packaging structure. Under the same power conditions, the light output energy efficiency can be improved, which is beneficial to energy saving and environmental protection.

[0054] In some embodiments of the present application, the second reflective film 14 covers the side wall of the LED chip 11 to increase the reflective area of ​​the second reflective film 14 and increase the amount of light incident on the color conversion film 12. Accordingly, in order to ensure the coating quality of the second reflective film 14 on the side wall of the LED chip 11, the coating process is completed by first coating the surface and the side surface as a whole, and then the reflective film on the surface of the LED chip 11 is removed by grinding to form the second reflective film 14 covering the side wall of the LED chip 11.

[0055] In some embodiments of the present application, the second reflective film 14 is spaced apart from the first reflective film 13 .

[0056] In the LED packaging structure provided by the embodiment of the present application, the second reflective film 14 is arranged on the side wall of the LED chip 11, and the first reflective film 13 is arranged on the side wall of the color conversion film 12. The reason why the second reflective film 14 needs to be arranged at intervals 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 LED chip 11 respectively. The color conversion film 12 and the LED 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 side wall of the LED chip 11 and the side wall of the color conversion film 12 by a one-time film forming method, in the process of removing the reflective film on the surface of the color conversion film 12, the grinding process is likely to cause the fixation of the colloid between the color conversion film 12 and the LED chip 11 to fail, and cause the relative position of the color conversion film 12 and the LED chip 11 to shift, affecting the light output effect and reducing the yield. In order to improve this problem, the present application adopts a method of forming films on the side walls of the light-emitting diode chip 11 and on the side walls of the color conversion film 12, respectively, to form discontinuous, spaced-apart first reflective film 13 and second reflective film 14, so as to ensure the connection stability and position matching between the color conversion film 12 and the light-emitting diode chip 11, thereby ensuring the light output effect and yield.

[0057] In some embodiments of the present application, the second reflective film 14 and the first reflective film 13 are made of the same material.

[0058] In the light-emitting diode packaging structure provided in the embodiment of the present application, since the second reflective film 14 and the first reflective film 13 are made of the same material, the first reflective film 13 and the second reflective film 14 can be respectively prepared by the same film-forming equipment, thereby reducing the production cost.

[0059] In some embodiments of the present application, the light-emitting diode chip 11 includes a base layer 111, and the surface of the base 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 base 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 base layer 111 is less than the thickness of the first transparent protective layer 121.

[0060] In the LED packaging structure provided by the embodiment of the present application, as mentioned above, the second reflective film 14 is spaced apart from the first reflective film 13. The present application adopts a method of forming films on the side walls of the LED chip 11 and on the side walls of the color conversion film 12, respectively, to form discontinuous, spaced apart first reflective film 13 and second reflective film 14. That is, both the LED chip 11 and the color conversion film 12 need to be subjected to surface grinding treatment to remove the reflective film on the surface of the LED chip 11 and the reflective film on the surface of the color conversion film 12.

[0061] As mentioned above, both the LED chip 11 and the color conversion film 12 need to be subjected to surface grinding treatment to remove the reflective film on the surface of the LED chip 11 and the reflective film on the surface of the color conversion film 12, that is, when the film-forming surface is based on the surface of the base layer 111, after the reflective film is formed on the surface and side of the LED chip 11, the reflective film on the surface of the base layer 111 will be removed by a grinding process. Due to the existence of grinding errors, at least part of the base layer 111 will be ground and removed. Therefore, when the material of the base layer 111 is the same as that of the first transparent protective layer 121 and the second transparent protective layer 123, the grinding process parameters used to remove the reflective film on the surface of the LED chip 11 can be the same as the grinding process parameters used to remove the reflective film on the surface of the color conversion film 12, which is conducive to reducing manufacturing costs and improving production yields.

[0062] In addition, in the preparation process of the light-emitting diode chip 11, taking the flip-chip LED chip as an example, each independent light-emitting diode chip 11 is formed by laser cutting and splitting processes, which will form an uneven blast point structure on the side wall of the base layer 111 of the light-emitting diode chip 11. In order to prevent the blast point structure from adversely affecting the reflection effect of the second reflective film 14 on the side wall of the light-emitting diode chip 11, the blast point structure will be removed by grinding, which will also reduce the thickness of the base layer 111. That is, the base layer 111 will undergo two thinning and grinding processes, which will make the thickness of the base layer 111 smaller than the thickness of the first transparent protective layer 121 and the second transparent protective layer 123.

[0063] In some embodiments of the present application, the light-emitting diode packaging structure also includes a bonding layer 15, which connects the base layer 111 and the first transparent protective layer 121, wherein the surface roughness of the first transparent protective layer 121 facing the bonding layer 15 is greater than the surface roughness 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.

[0064] In the light-emitting diode packaging structure provided in the embodiment of the present application, the bonding layer 15 arranged between the base layer 111 and the first transparent protective layer 121 is used to bond and fix the light-emitting diode chip 11 and the color conversion film 12. In order to improve the bonding effect of the bonding layer 15 on the color conversion film 12, it is necessary to make the surface roughness of the first transparent protective layer 121 facing the bonding layer 15 on the side greater than a preset value, and the method for improving the surface roughness of the first transparent protective layer 121 facing the bonding layer 15 on the side can be grinding.

[0065] As mentioned above, a first reflective film 13 with high coating quality can be formed on the side wall of the color conversion film 12 by first coating 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 and removing the reflective film on the surface of the first transparent protective layer 121. 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, thereby making the light-emitting diode packaging structure have a smaller light output angle and a higher front light output intensity.

[0066] That is, by first coating 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 and removing 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 output angle and a higher front light output intensity, but also, by controlling the grinding process parameters, the surface roughness of the first transparent protective layer 121 on the side facing the bonding layer 15 can be simultaneously made greater than the surface roughness of the second transparent protective layer 123 on the side away from the color conversion layer 122, thereby improving the bonding effect of the bonding layer 15 to the color conversion film 12, and improving the structural stability and product yield.

[0067] In some embodiments of the present application, the bonding layer 15 does not include color conversion particles. Since the bonding layer 15 does not include color conversion particles, the adhesion of the bonding layer 15 can be improved, and there is no need to consider the material selection limitations caused by the introduction of color conversion particles, so that the bonding layer 15 can use materials with higher temperature resistance strength to improve the temperature resistance of the light-emitting diode packaging structure.

[0068] In some embodiments of the present application, the color conversion layer 122 includes fluorescent powder but does not include silica gel, and the fluorescent powder is sintered and fixed to the first transparent protective layer 121 and the second transparent protective layer 123 .

[0069] In the light-emitting diode packaging structure provided in the embodiment of the present application, the color conversion layer 122 includes fluorescent powder but 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, and is not a conventional fluorescent glue layer. Compared with the dispersed distribution form of fluorescent powder in the related art, the distribution form of fluorescent powder is more concentrated, which is more conducive to the control of the light output angle.

[0070] In some embodiments of the present application, the color conversion layer 122 includes only phosphors, and there are gaps between adjacent phosphors. The phosphors are sealed in a closed space formed by the first reflective film 13 and the first transparent protective layer 121 and the second transparent protective layer 123 .

[0071] In some embodiments of the present application, the thickness of the color conversion layer 122 is less than or equal to 60 micrometers, and the difference between the maximum particle size and the minimum particle size of the phosphor in the color conversion layer 122 is less than 40 micrometers.

[0072] In the light-emitting diode packaging structure provided by the embodiment 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 and fixing, the difference between the maximum particle size and the minimum particle size of the phosphor in the color conversion layer 122 should be controlled, and specifically controlled within the range of 0 to 40 microns.

[0073] Figure 3 A cross-sectional schematic diagram of a light emitting diode chip provided in some embodiments of the present application. Figure 1 , Figure 2 and Figure 3As shown, in some embodiments of the present application, the light-emitting diode chip 11 includes a chip body 112 and the base layer 111, and the chip body 112 is arranged on a side of the base layer 111 away from the color conversion film 12. Optionally, in the direction in which the base layer 111 is 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 that are stacked in sequence, 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, and 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 may further include a current spreading layer X6, an ohmic contact layer X7, and a current blocking layer X8 disposed on a side of the second type semiconductor layer X4 away from the base 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.

[0074] 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, etc.

[0075] 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.

[0076] In a second aspect, some embodiments of the present application provide a method for preparing a light-emitting diode packaging structure, the method for preparing the light-emitting diode packaging structure comprising the following steps: placing a light-emitting diode chip and a color conversion film on a carrier table whose surface is coated with a UV debonding film, 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 of the surfaces and each side wall of the color conversion film, and depositing a second reflective film on one of the surfaces 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 a baking treatment to fix the color conversion film on the light-emitting surface of the light-emitting diode chip.

[0077] In the preparation method of the light-emitting diode packaging structure provided in the embodiment of the present application, the light-emitting diode chip and the color conversion film are arranged on a carrier table whose surface is coated with a UV debonding film, so that the light-emitting diode chip and the color conversion film can be well fixed. Compared with the conventional adhesive film fixation, the fixing effect can be greatly improved to avoid the position displacement of the light-emitting diode chip and the color conversion film during the subsequent grinding process, and after the grinding is completed, the UV debonding film can be treated with UV light to facilitate the peeling of the light-emitting diode chip and the color conversion film, and has a good peeling yield.

[0078] In the method for preparing the light-emitting diode packaging structure provided in the embodiment of the present application, a first reflective film is deposited on one of the surfaces and each side wall of the color conversion film to improve the film-forming quality and stability of the first reflective film formed on the side wall of the color conversion film; a second reflective film is deposited on one of the surfaces and each side wall of the light-emitting diode chip 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 a film-forming device for film-forming at the same time, that is, the film-forming process of the first reflective film is carried out synchronously with the film-forming process of the second reflective film to reduce the process steps and reduce 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 also be carried out sequentially.

[0079] In the preparation method of the light-emitting diode package structure provided in the embodiment of the present application, the first reflective film on the surface of the color conversion film is removed by grinding, and the first reflective film can be retained intact 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 output angle of the subsequently formed light-emitting diode package structure and improving the front light output intensity; the second reflective film on the surface of the light-emitting diode chip is removed by grinding, and the second reflective film can be retained intact 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, so as to improve the problem of light leakage caused by the side light output of the light-emitting diode chip, and can effectively increase the front light output, improve the front light output efficiency and brightness. In addition, since 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, the color conversion layer can be protected to prevent the color conversion particles in the color conversion layer from being ground and removed during the grinding process, thereby ensuring the color rendering accuracy of the light-emitting diode package structure, better controlling the color temperature range, and improving the product yield.

[0080] In the preparation method of the light-emitting diode packaging structure provided in the embodiment of the present application, an adhesive layer is formed on the light-emitting surface of the light-emitting diode chip, and the color conversion film is arranged on the adhesive layer, and a baking treatment is performed, so that the light-emitting diode chip and the color conversion film can be fixedly connected by using the adhesive layer, thereby forming a light-emitting diode packaging structure.

[0081] Figure 4 A schematic diagram of a method for preparing a light emitting diode packaging structure provided in some embodiments of the present application, referring to Figure 4 As shown, in some embodiments of the present application, the method for preparing the light emitting diode package structure includes step S10, step S20, step S30, step S40, and step S50.

[0082] Figure 5a This is a schematic diagram corresponding to step S10 provided in some embodiments of the present application. Figure 4 and Figure 5a As shown, step S10 includes: grinding the base layer 111 in the light emitting diode chip 11 to remove the explosion point structure Z1 in the base layer 111 .

[0083] Figure 5b The schematic diagram corresponding to step S20 provided in some embodiments of the present application. Figure 4 and Figure 5b As shown, step S20 includes: placing the light-emitting diode chip 11 and the color conversion film 12 on a carrier 16 whose surface is coated with a UV debonding film 17, 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 a side of the second transparent protective layer 123 away from the carrier 16.

[0084] Figure 5c The schematic diagram corresponding to step S30 provided in some embodiments of the present application. Figure 4 and Figure 5c As shown, 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, one surface of the light-emitting diode chip 11 may be the light-emitting surface Q1 of the light-emitting diode chip 11, or the backlight surface of the light-emitting diode chip 11. Figure 5c It is shown that a second reflective film 14 is deposited on the backlight surface and each side wall of the light emitting diode chip 11 .

[0085] Figure 5d The schematic diagram corresponding to step S30 provided in some embodiments of the present application. Figure 4 and Figure 5d As shown, 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.

[0086] Figure 5e The schematic diagram corresponding to step S30 provided in some embodiments of the present application. Figure 4 and Figure 5e As shown, step S50 includes: forming an adhesive layer 15 on the light emitting surface Q1 of the LED 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 LED chip 11.

[0087] In the preparation method of the light-emitting diode packaging structure provided in the embodiment of the present application, in the process of forming an independent light-emitting diode chip 11, it is necessary to go through the process of laser cutting and splitting, which will form an uneven explosion point structure Z1 on the side wall of the base layer 111 of the light-emitting diode chip 11. In order to avoid the explosion point structure Z1 from adversely affecting the reflection effect of the second reflective film 14 on the side wall of the light-emitting diode chip 11, the explosion point structure Z1 will be removed by grinding, which also shows that the grinding equipment for removing the explosion point structure Z1 can also be used in the subsequent reflection film grinding and removal process, which can effectively reduce the equipment cost. In addition, since the process of grinding to remove the explosion point structure Z1 has been performed on the light-emitting diode chip 11 before the second reflective film 14 is deposited on one of the surfaces and each side wall of the light-emitting diode chip 11, this can effectively improve the film quality and film stability of the second reflective film 14 on the side wall of the light-emitting diode chip 11.

[0088] Figure 6 A schematic diagram of a method for preparing a light emitting diode packaging structure provided in some embodiments of the present application, referring to Figure 6 As shown, in some embodiments of the present application, the method for preparing the light emitting diode package structure includes step M10, step M20, step M30, and step M40.

[0089] Figure 7a This is a schematic diagram corresponding to step M10 provided in some embodiments of the present application. Figure 6 and Figure 7a As shown, step M10 includes: placing the light-emitting diode chip 11 and the color conversion film 12 on a carrier 16 whose surface is coated with a UV debonding film 17, 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.

[0090] Figure 7b The schematic diagram corresponding to step M20 provided in some embodiments of the present application. Figure 6 and Figure 7b As shown, step M20 includes: depositing a first reflective film 13 on one of the surfaces and each side wall of the color conversion film 12, and depositing a second reflective film 14 on one of the surfaces and each side wall of the light-emitting diode chip 11, wherein one of the surfaces of the light-emitting diode chip 11 is the surface of the base layer 111 facing away from the chip body 112.

[0091] Figure 7c The schematic diagram corresponding to step M30 provided in some embodiments of the present application. Figure 6 and Figure 7c As shown, 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 LED chip 11 and the explosion point structure Z1 in the base layer 111 in the LED chip 11 by grinding.

[0092] Figure 7d The schematic diagram corresponding to step M30 provided in some embodiments of the present application. Figure 6 and Figure 7d As shown, step M40 includes: forming an adhesive layer 15 on the light emitting surface Q1 of the LED chip 11, 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 LED chip 11.

[0093] In the method for preparing the light-emitting diode packaging structure provided in the embodiment of the present application, the second reflective film 14 on the surface of the light-emitting diode chip 11 and the blast point structure Z1 in the base layer 111 in the light-emitting diode chip 11 can be removed by a single grinding process, which can reduce the process steps and reduce the production cost. In addition, in order to ensure the film quality and stability of the second reflective film 14 on the side wall of the light-emitting diode chip 11, the light-emitting diode chip 11 can be over-grinded, that is, the grinding depth is further increased on the basis of the depth of the blast point structure Z1.

[0094] In summary, the present application provides a light-emitting diode packaging structure and a preparation method thereof, wherein the light-emitting diode packaging structure includes a light-emitting diode chip, a color conversion film and a first reflective film, wherein the color conversion film is arranged on the light-emitting surface of the light-emitting diode chip, and the first reflective film is arranged on the side wall of the color conversion film; wherein 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 provided by the present application, the first reflective film arranged on the side wall of the color conversion film can reduce the light-emitting angle and increase the front light emission, and since a transparent protective layer is arranged on the outer side of the color conversion layer, the color conversion layer can be protected during the grinding process, so that the color temperature range of the light-emitting diode packaging structure can be within a normal range, thereby improving the production yield of the light-emitting diode packaging structure.

[0095] The above is a detailed introduction to a light-emitting diode packaging structure and a preparation method thereof provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A light emitting diode packaging structure, characterized in that: The light emitting diode packaging structure comprises: Light emitting diode chips; A color conversion film is arranged on the light emitting surface of the light emitting diode chip; A first reflective film is disposed on the side wall of the color conversion film and covers 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; The light-emitting diode packaging structure also includes an adhesive layer, which connects the light-emitting diode chip's light-emitting surface and the first transparent protective layer, wherein the surface roughness of the first transparent protective layer facing the adhesive layer is greater than the surface roughness of the second transparent protective layer facing 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.

2. The light emitting diode packaging structure according to claim 1, characterized in that: The light emitting diode packaging structure further includes a second reflective film, which is disposed on a side wall of the light emitting diode chip and is spaced apart from the first reflective film.

3. The light emitting diode packaging structure according to claim 2, characterized in that: The second reflective film is made of the same material as the first reflective film.

4. The light emitting diode packaging structure according to claim 2, characterized in that: The light-emitting diode chip includes a base layer, and the surface of the base layer facing the color conversion film is the light-emitting surface of the light-emitting diode chip, wherein the material of the base layer is the same as that 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.

5. The light emitting diode packaging structure according to claim 1, characterized in that: The color conversion layer includes fluorescent powder but does not include silica gel, and the fluorescent powder is sintered and fixed to the first transparent protective layer and the second transparent protective layer.

6. The light emitting diode packaging structure according to claim 5, characterized in that: The thickness of the color conversion layer is less than or equal to 60 micrometers, and the difference between the maximum particle size and the minimum particle size of the phosphor in the color conversion layer is less than 40 micrometers.

7. A method for preparing a light emitting diode packaging structure, characterized in that: The method for preparing the light emitting diode packaging structure comprises the following steps: The light-emitting diode chip and the color conversion film are arranged on a carrier with a UV debonding film coated on the surface, wherein the color conversion film comprises a first transparent protective layer, a color conversion layer and a second transparent protective layer; A first reflective film is deposited on one surface and each side wall of the color conversion film, and a second reflective film is deposited on one surface and each side wall of the light-emitting diode chip, wherein the first reflective film covers the side wall of the color conversion film, and one surface of the color conversion film is a surface of the first transparent protective layer on a side away from the color conversion layer; removing the first reflective film and at least a portion 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 less than the thickness of the second transparent protective layer, and the surface roughness of the first transparent protective layer on the side away from the color conversion layer is greater than the surface roughness of the second transparent protective layer on the side away from the color conversion layer; removing the second reflective film on the surface of the light-emitting diode chip by grinding; An adhesive layer is formed on the light emitting surface of the light emitting diode chip, and the color conversion film is arranged on the adhesive layer, and a baking treatment is performed to fix the color conversion film on the light emitting surface of the light emitting diode chip, wherein the adhesive 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 stacked on the light emitting surface of the light emitting diode chip.

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