Heat-conducting fluorescent silicon resin film as well as preparation method and application thereof

Abstract

The invention discloses a heat-conducting fluorescent silicon resin film as well as a preparation method and application thereof, and relates to the technical field of LED packaging materials. A heat-conducting fluorescent silicon resin film is formed by mixing, coating, drying and curing silicon resin AB glue, fluorescent powder, anti-precipitation powder and borosilicate glass powder, the addition amount of the anti-precipitation powder accounts for 0.3-0.8% of the total mass of the silicon resin AB glue, and the addition amount of the borosilicate glass powder accounts for 10-12% of the total mass of the silicon resin AB glue. By adopting the scheme, the heat-conducting property of the prepared fluorescent silicon resin film can be effectively improved. Furthermore, the heat-conducting fluorescent silicon resin film prepared by the scheme is used for packaging an LED chip, so that the reliability of the packaged LED chip is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED packaging materials, in particular to a heat-conducting fluorescent silicone resin film and a preparation method and application thereof. BACKGROUND

[0002] The application field of LED packaging has developed rapidly in recent years and plays an important role in many fields such as lighting and display. With the continuous progress of LED technology, the light-emitting efficiency and power of LED chips are continuously improved, which makes the requirements for packaging materials and packaging processes increasingly stringent. Good packaging not only protects the LED chip and prolongs its service life, but also improves the light-emitting efficiency and reliability of the LED chip, which is of great significance to the development of the LED industry.

[0003] In terms of light conversion structure of LED packaging, there are currently three main ways on the market, namely, dispensing, spraying and prefabricated film. Among them, the prefabricated film process is relatively common in the field of LED packaging. The mainstream prefabricated film process can be divided into mold pressing film and coating film. Usually, the silicone AB potting adhesive and the fluorescent powder are stirred in a certain proportion, mixed uniformly after vacuumizing, and then formed in a mold or coated on a release film and dried to obtain a prefabricated silicone resin film. Then, the prepared silicone resin film is cut into film particles of a specified size and arranged in order, and then the film particles are attached to the flip-chip LED chip using a film fixing device, and then the subsequent LED packaging process is entered.

[0004] Then, since the thermal conductivity of the conventional silicone AB potting adhesive is low, usually only between 0.1-0.3 W / (m·K), the low thermal conductivity characteristic is easy to cause the LED chip to heat up after packaging, thereby causing the surface temperature to be high, which affects the reliability of the subsequent LED device. SUMMARY

[0005] In order to improve the heat conduction performance of the fluorescent silicone resin film and thereby improve the reliability of the packaged LED chip, the present application provides a heat-conducting fluorescent silicone resin film and a preparation method and application thereof.

[0006] In a first aspect, the heat-conducting fluorescent silicone resin film provided by the present application adopts the following technical solution: A heat-conducting fluorescent silicone resin film is formed by coating and drying and curing a mixture of silicone AB adhesive, fluorescent powder, anti-settling powder and borosilicate glass powder; The silicone AB adhesive comprises A adhesive and B adhesive, and the mass ratio of the A adhesive to the B adhesive is 10: (1-10); The addition amount of the fluorescent powder accounts for 35-500% of the total mass of the silicone AB adhesive; The addition amount of the anti-settling powder accounts for 0.3-0.8% of the total mass of the silicone AB adhesive; The adding amount of the borosilicate glass powder accounts for 10-12% of the total mass of the silicone AB glue.

[0007] By adopting the above technical scheme, the introduction of the borosilicate glass powder effectively improves the heat conduction and heat dissipation performance of the fluorescent silicone resin film, and effectively reduces the surface area heat of the fluorescent silicone resin film during normal operation, which is beneficial to improve the reliability of the packaged LED chip. In addition, due to the large difference in density between the borosilicate glass powder and the silicone AB glue, the introduction of the anti-settling powder can prevent the borosilicate glass powder from settling to a certain extent, which is beneficial to prevent the problem of uneven performance of the fluorescent silicone resin film caused by the spontaneous precipitation of the borosilicate glass powder during the film forming process.

[0008] Optionally, the boron content in the borosilicate glass powder is 12.5-13.5%, and the silicon content is greater than 80%.

[0009] By adopting the above technical scheme, it is beneficial to control the linear expansion coefficient of the borosilicate glass powder, so as to ensure the heat conduction performance and aging fatigue resistance of the prepared fluorescent silicone resin film, and improve the reliability of the packaged LED chip.

[0010] Optionally, the particle size distribution of the borosilicate glass powder is D50=0.8μm, D97=1μm.

[0011] By adopting the above technical scheme, it is beneficial to make the borosilicate glass powder uniformly and densely distributed in the fluorescent silicone resin film, so as to ensure that the fluorescent silicone resin film has a dense heat conduction network and good heat conduction performance.

[0012] Optionally, the mixed viscosity of the silicone AB glue is 4300-4500mPa・s, and the elongation rate of the cured silicone AB glue is 40-60%.

[0013] By adopting the above technical scheme, it is beneficial for the silicone AB glue to form a wet film with uniform thickness by coating, and at the same time, it can ensure that the formed fluorescent silicone resin film has good flexibility, which is beneficial to prevent stress concentration and cracking caused by temperature cycle changes, and is beneficial to ensure the long-term reliability of the packaged LED chip.

[0014] Optionally, the fluorescent powder is at least one of silicate fluorescent powder, aluminate fluorescent powder, chlorosilicate fluorescent powder, nitride fluorescent powder, phosphate fluorescent powder, fluoride fluorescent powder, molybdate fluorescent powder and quantum dot fluorescent powder, and the particle size distribution of the fluorescent powder is D50=10μm, D97=12μm.

[0015] Optionally, the anti-settling powder is hydrophobic fumed silica.

[0016] By adopting the technical scheme, the viscosity and fluidity of the system can be adjusted, the mixed slurry is more suitable for coating into a film with a certain thickness, the stability of the borosilicate glass powder in the system is improved, the borosilicate glass powder is prevented from settling in the system, and the uniform dispersion of the borosilicate glass powder in the fluorescent silicon resin film is ensured.

[0017] In a second aspect, the application provides a preparation method of the heat-conducting fluorescent silicon resin film, which adopts the following technical scheme: A preparation method of a heat-conducting fluorescent silicon resin film, comprising the following steps: S1, A glue, fluorescent powder and are mixed by a predetermined proportion, and a sufficient amount of borosilicate glass powder is added in batches for multiple times while stirring continuously, the stirring is maintained until the borosilicate glass powder is dispersed uniformly after the addition is completed, then B glue is added, and the mixture is stirred and mixed in a vacuum environment to obtain a fluorescent film slurry; S2, the fluorescent film slurry prepared in S1 is coated on a release film, and then dried and cured in an oven, and the fluorescent silicon resin film is obtained after being taken out.

[0018] By adopting the technical scheme, the borosilicate glass powder is added in batches for multiple times, which is beneficial to prevent the borosilicate glass powder from agglomerating after being added, and the borosilicate glass powder is uniformly dispersed in the fluorescent film slurry, so that the subsequent prepared fluorescent silicon resin film has uniform overall heat-conducting performance, and hot spots are effectively prevented from accumulating, which is beneficial to improve the reliability of the fluorescent silicon resin film as an LED packaging material. In addition, the overall preparation process is simple, which is beneficial to mass production in factories.

[0019] Optionally, in S2, the fluorescent film slurry is coated by a doctor blade coating method, and the coating thickness is 50-120 μm.

[0020] By adopting the technical scheme, the doctor blade coating method can directly and accurately set and remove excess fluorescent film slurry, and form a uniform and consistent thickness wet film on the release film, which is beneficial to ensure the flatness of the prepared fluorescent silicon resin film, and prevent defects such as uneven color temperature, local overheating or accelerated reliability degradation of the packaged LED chip caused by uneven thickness of the fluorescent silicon resin film.

[0021] Optionally, in S2, the temperature of the oven is controlled to be 90-100℃, and the drying time is 120-150 min.

[0022] In a third aspect, the application provides an application of the heat-conducting fluorescent silicon resin film, which adopts the following technical scheme: An application of a heat-conducting fluorescent silicon resin film, which is used for packaging of flip-chip LED chips.

[0023] To sum up, the technical scheme of the present application has at least one of the following beneficial effects: 1. The preparation of the fluorescent silicon resin film by introducing borosilicate glass powder can effectively improve the heat conduction and heat dissipation performance of the fluorescent silicon resin film, and can solve the problem of surface heat of the fluorescent silicon resin film during normal operation, which is beneficial to improve the reliability of the packaged LED chip.

[0024] 2. By introducing anti-settling powder and borosilicate glass powder, the anti-settling powder can prevent the spontaneous settling of borosilicate glass powder, which is beneficial to prevent the uneven performance of the fluorescent silicon resin film caused by the spontaneous settling of borosilicate glass powder during the film preparation process.

[0025] 3. By strictly controlling the boron-silicon content and particle size distribution range of the borosilicate glass powder, the prepared fluorescent silicon resin film can effectively ensure good heat conduction and heat dissipation performance, which is beneficial to improve the reliability of the LED chip packaged by it. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structure diagram of a flip-chip LED chip packaging assembly in application example 1.

[0027] MARKED DESCRIPTION: 1, light source support; 2, LED chip; 3, dispensing layer; 4, fluorescent film. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in combination with examples and comparative examples.

[0029] The silicon resin AB glue is selected from Huixi New Materials, including PS-8136 (25℃ mixed viscosity 4300mPa・s, elongation after curing 60%, hardness D49), PS-8228 (25℃ mixed viscosity 4500mPa・s, elongation after curing 40%, hardness D49).

[0030] The fumed silica is selected from hydrophobic fumed silica of Hui Fu Nanometer Materials, and the specific brand is HB-151.

[0031] The borosilicate glass powder is selected from Hui Fu Nanometer Materials, and the specific boron and silicon content and particle size are customized by the manufacturer according to the requirements. EXAMPLE

[0032]

Example 1

[0033] In the embodiment, the silicone AB glue is specifically selected from a brand PS-8136. Specifically, the brand silicone AB glue includes A glue and B glue, and the mixing mass ratio of the A glue and the B glue is 10:1, that is, the silicone AB glue includes 10 kg of A glue and 1 kg of B glue.

[0034] In the embodiment, the fluorescent powder is selected from silicate green fluorescent powder, specifically, American Intem G2762, and the particle size distribution of the fluorescent powder is controlled to be D50=10 μm and D97=12 μm. The anti-settling powder is selected from hydrophobic fumed silica. The borosilicate glass powder is selected from high borosilicate glass powder, wherein the boron content is 12.9%, the silicon content is 80.5%, the particle size distribution is D50=0.8 μm and D97=1 μm.

[0035] A preparation method of a heat-conducting fluorescent silicone film, including the following steps: S1, mixing the silicone A glue, the fluorescent color powder and the borosilicate glass powder according to a preset ratio, continuously stirring and adding the same amount of borosilicate glass powder in batches for multiple times, adding only 20% of the borosilicate glass powder each time and stirring and mixing for 1 min, keeping stirring for 5 min after the addition of the borosilicate glass powder is completed until it is uniformly dispersed, then adding the silicone B glue, and stirring and mixing in a vacuum environment to obtain a fluorescent film slurry; S2, coating the fluorescent film slurry prepared in S1 on a release film, and then placing it in an oven for drying and curing, wherein the oven temperature is 100°C, and the drying and curing time is 120 min, and the obtained fluorescent silicone film is taken out.

[0036]

Embodiment 2

[0037] In the embodiment, the silicone AB glue is specifically selected from a brand PS-8228. Specifically, the brand silicone AB glue includes A glue and B glue, and the mixing mass ratio of the A glue and the B glue is 10:1, that is, the silicone AB glue includes 10 kg of A glue and 1 kg of B glue.

[0038] In the embodiment, the fluorescent powder is selected from aluminate yellow fluorescent powder, specifically, American Intem YAG04, and the particle size distribution of the fluorescent powder is controlled to be D50=10 μm and D97=12 μm. The anti-settling powder is selected from hydrophobic fumed silica. The borosilicate glass powder is selected from high borosilicate glass powder, wherein the boron content is 12.9%, the silicon content is 80.5%, the particle size distribution is D50=0.8 μm and D97=1 μm.

[0039] A preparation method of a heat-conducting fluorescent silicone film, including the following steps: S1. Mix silicone resin A, fluorescent pigment and other ingredients thoroughly according to the preset ratio. Continue stirring and add equal amounts of borosilicate glass powder in batches. Add only 20% borosilicate glass powder each time and stir for 1 minute. After the borosilicate glass powder is added, keep stirring for 5 minutes until it is evenly dispersed. Then add silicone resin B and place it in a vacuum environment to stir and mix thoroughly to obtain fluorescent film slurry. S2. The fluorescent film slurry obtained in S1 is coated onto the release film with a coating thickness of 120 μm. Then, it is placed in an oven to dry and cure. The oven temperature is 90°C and the drying and curing time is 150 min. After removal, the fluorescent silicone resin film is obtained.

[0040]

Example 3

[0041] In this embodiment, the borosilicate glass powder used is medium borosilicate glass powder, wherein the boron content is 8.5%, the silicon content is 75.5%, and the particle size distribution is D50=0.8μm and D97=1μm.

[0042]

Example 4

[0043] In this embodiment, the particle size distribution of the borosilicate glass powder is D50=2μm and D97=3.5μm.

[0044]

Example 5

[0045] In this embodiment, the particle size distribution of the borosilicate glass powder is D50=8μm and D97=10μm. Comparative Example

[0046] Comparative Example 1 A fluorescent silicone resin film, which differs from [Example 1] in that it does not contain borosilicate glass powder.

[0047] Comparative Example 2 A fluorescent silicone resin film, which differs from [Example 1] in that it does not contain anti-precipitation powder. Application examples

[0048]

Application Example 1

[0049]

Application Example 2

[0050] In this application example, the fluorescent film 4 is specifically the thermally conductive fluorescent silicone resin film prepared in [Example 2].

[0051]

Application Example 3

[0052] In this application example, the fluorescent film 4 is specifically the thermally conductive fluorescent silicone film prepared in [Example 3].

[0053]

Application Example 4

[0054] In this application example, the fluorescent film 4 is specifically the thermally conductive fluorescent silicone film prepared in [Example 4].

[0055]

Application Example 5

[0056] In this application example, the fluorescent film 4 is specifically the thermally conductive fluorescent silicone film prepared in [Example 5].

[0057]

Comparative Application Example 1

[0058] In this application example, the fluorescent film 4 is specifically the fluorescent silicone film prepared in [Comparative Example 1].

[0059]

Comparative Application Example 2

[0060] In this application example, the fluorescent film 4 is specifically the fluorescent silicone film prepared in [Comparative Example 2]. Performance test data

[0061] 1. Thin-film heat dissipation performance: The flip-chip LED packaged components obtained in Application Examples 1-5 and Comparative Examples 1-2 were continuously operated for 12 hours at a certain ambient temperature. Then, the temperature (°C) of the fluorescent thin film surface in each application example was measured and recorded. For each application example, three sets of test samples were set up, and the average value of the measured temperature of the three sets of test samples was recorded and rounded to the nearest integer.

[0062] 2. Reliability performance testing: The tests were conducted according to IES LM80, and the light decay of each application case after 9000 hours of continuous aging was detected. The test temperature was 85℃, and the corresponding surface thermal resistance change rate was measured at the same time.

[0063] Table 1 Performance test data of fluorescent silicone resin film

[0064] Combining Application Example 1-2 and Comparative Application Example 1-2 with the test data in Table 1, it can be seen that introducing anti-precipitation powder and borosilicate glass powder into the silicone AB adhesive can effectively improve the thermal conductivity of the prepared fluorescent silicone resin film, thereby improving the reliability of the LED chip encapsulated with the fluorescent silicone resin film.

[0065] As can be seen from the comparison between Application Example 1 and Comparative Application Example 1, the introduction of borosilicate glass powder can effectively reduce the surface heat accumulation of the fluorescent silicone resin film during normal operation. Since the heat accumulation of the fluorescent silicone resin film on the surface is reduced during operation, the packaged LED chip can still maintain good overall performance after long-term use or aging. It not only has a low light decay, but also a low thermal resistance change rate, and has better reliability. As can be seen from the comparison between Application Example 1 and Comparative Application Example 2, the absence of hydrophobic fumed silica as an anti-precipitation powder in Comparative Application Example 2 resulted in insufficient heat dissipation and a small amount of surface heat accumulation in the fluorescent silicone resin film at high temperatures, directly affecting the reliability of subsequent LED chip encapsulation. This may be because the hydrophobic fumed silica not only regulates the viscosity of the system but also helps prevent the sedimentation of borosilicate glass powder. Due to the large density difference between borosilicate glass powder and silicone AB glue, it is prone to spontaneous sedimentation during coating and curing. However, hydrophobic fumed silica can be interconnected through physical forces such as hydrogen bonds between particles, forming a thixotropic network structure in the silicone AB glue. This structure perfectly balances the fluidity during construction and the anti-precipitation properties during static conditions. It allows the system to flow fully during stirring and promotes uniform dispersion of borosilicate glass powder, while preventing borosilicate glass powder sedimentation during static curing. This helps prevent the fluorescent silicone resin film from having insufficient upper layer performance and excessive lower layer performance due to sedimentation.

[0066] Combining Application Examples 1 and 3-4 with the test data in Table 1, it can be seen that the type and particle size of borosilicate glass powder also affect the thermal conductivity of the fluorescent silicone resin film and the reliability of the encapsulated LED chip.

[0067] As shown in Application Examples 1 and 3, the thermal conductivity of the fluorescent silicone resin film prepared using borosilicate glass powder with a boron content of 8.5% is weaker than that prepared using high borosilicate glass powder with a boron content of 12.9%. This is because as the boron content decreases, the coefficient of linear expansion of the borosilicate glass powder increases. With rising ambient temperature, the borosilicate glass powder is more prone to expansion, generating significant internal stress within the system. This affects the thermal conductivity and heat dissipation efficiency of the fluorescent silicone resin film. Furthermore, the continuous expansion and contraction during the temperature cycling of the encapsulated LED chip also causes cyclical changes in the significant internal stress, accelerating the aging and fatigue of the fluorescent silicone resin film and directly resulting in a decrease in the reliability of the encapsulated LED chip. As shown in Application Examples 1 and 4, using borosilicate glass powder with a larger particle size reduces the thermal conductivity and heat dissipation effect of the fluorescent silicone resin film, and the decreasing trend gradually flattens. This may be because as the particle size of borosilicate glass powder increases further, the number of particles per unit volume decreases while the amount added remains constant. This leads to a decrease in the density of thermally conductive nodes formed between particles, resulting in a sparser thermally conductive network in the fluorescent silicone resin film. Consequently, the overall thermal conductivity shows a significant downward trend, especially at high temperatures. However, with further increases in particle size, larger-diameter borosilicate glass powder particles are more likely to come into contact with each other and form thermally conductive paths when constructing thermally conductive channels of the same volume. This, in turn, reduces the overall thermal resistance of the fluorescent silicone resin film, thus gradually leveling off the downward trend in thermal conductivity.

[0068] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A thermally conductive fluorescent silicone resin film, characterized in that: It is made by mixing silicone resin AB glue, fluorescent powder, anti-precipitation powder and borosilicate glass powder, coating and drying to cure; The silicone resin AB adhesive includes adhesive A and adhesive B, and the mass ratio of adhesive A to adhesive B is 10:(1-10). The amount of phosphor added accounts for 35-500% of the total mass of the silicone AB adhesive; The amount of the anti-settling powder added accounts for 0.3-0.8% of the total mass of the silicone resin AB glue; The amount of borosilicate glass powder added accounts for 10-12% of the total mass of the silicone resin AB glue.

2. The thermally conductive fluorescent silicone resin film according to claim 1, characterized in that: The borosilicate glass powder contains 12.5-13.5% boron and more than 80% silicon.

3. The thermally conductive fluorescent silicone resin film according to claim 2, characterized in that: The borosilicate glass powder has a particle size distribution of D50=0.8μm and D97=1μm.

4. The thermally conductive fluorescent silicone resin film according to claim 1, characterized in that: The mixed viscosity of the silicone AB adhesive is 4300-4500 mPa·s, and the elongation of the cured silicone AB adhesive is 40-60%.

5. The thermally conductive fluorescent silicone resin film according to claim 1, characterized in that: The phosphor is at least one of silicate phosphor, aluminate phosphor, chlorosilicate phosphor, nitride phosphor, phosphate phosphor, fluoride phosphor, molybdate phosphor, and quantum dot phosphor, and the particle size distribution of the phosphor is D50=10μm and D97=12μm.

6. The thermally conductive fluorescent silicone resin film according to claim 1, characterized in that: The anti-precipitation powder is hydrophobic fumed silica.

7. A method for preparing a thermally conductive fluorescent silicone resin film, used to prepare the thermally conductive fluorescent silicone resin film as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Mix A glue, phosphor powder and other ingredients thoroughly according to the preset ratio. Continue stirring and add equal amounts of borosilicate glass powder in batches. After the addition is complete, keep stirring until the mixture is evenly dispersed. Then add B glue and mix thoroughly under vacuum to obtain the fluorescent film slurry. S2. The fluorescent film slurry obtained in S1 is coated onto the release film, and then placed in an oven to dry and cure. After removal, the fluorescent silicone resin film is obtained.

8. The method for preparing a thermally conductive fluorescent silicone resin film according to claim 7, characterized in that: In step S2, the fluorescent film slurry is coated using a doctor blade coating method, with a coating thickness of 50-120 μm.

9. The method for preparing a thermally conductive fluorescent silicone resin film according to claim 7, characterized in that: In step S2, the temperature of the oven is controlled to be 90-100℃ and the drying time is 120-150min.

10. An application of a thermally conductive fluorescent silicone resin film, applicable to the thermally conductive fluorescent silicone resin film as described in any one of claims 1-6, characterized in that, It is used in the packaging of flip-chip LEDs.

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