LED packaging device and its preparation method and application

Abstract

This invention provides an LED packaging device, its preparation method, and its application, relating to the field of semiconductor device technology. The preparation method includes: mixing encapsulation silicone and phosphor in a preset ratio, and then preparing a film of a preset thickness using a film scraping machine; curing the film at a first preset temperature for a first preset time to complete the first curing, obtaining a semi-cured phosphor sheet; transferring the semi-cured phosphor sheet onto a flip-chip that has been die-bonded in a support, and vacuum-pressing it to ensure that the semi-cured phosphor sheet completely adheres to the surface and sides of the flip-chip; curing the vacuum-pressed semi-cured phosphor sheet at a second preset temperature for a second preset time to complete the second curing, obtaining a cured finished product; and encapsulating the cured finished product with transparent adhesive to obtain an LED packaging device. This invention can solve the technical problems of poor adhesive dispensing stability and uneven phosphor distribution in existing LED packaging devices, which lead to a decrease in brightness and concentration.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, specifically to an LED packaging device, its preparation method, and its application. Background Technology

[0002] LED packaging devices are widely used in lighting, display and backlight fields due to their unique optoelectronic properties and ultra-long lifespan, and have attracted widespread attention as a next-generation lighting method with clear advantages.

[0003] Typically, LED packaging devices consist of a substrate, LED chip, adhesive, and phosphor. The manufacturing process generally involves die bonding, bonding, dispensing, and testing. However, during the dispensing process, insufficient stability in the amount of adhesive applied, or uneven distribution of phosphor within the phosphor resulting in high dispersion and poor concentration, can lead to a decrease in the brightness and density of the LED packaging device. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an LED packaging device, its preparation method and application, which aims to solve the technical problems of poor adhesive dispensing stability and uneven phosphor distribution in LED packaging devices, resulting in a decrease in brightness and concentration.

[0005] A first aspect of the present invention is to provide a method for fabricating an LED packaged device, the method comprising:

[0006] The encapsulating silicone and phosphor are mixed in a preset ratio, and then a film of a preset thickness is prepared by a film coating machine.

[0007] The film is cured at a first preset temperature for a first preset time to complete one curing process, resulting in a semi-cured fluorescent sheet;

[0008] The semi-cured phosphor is transferred to the flip-chip LED that has been die-bonded in the support, and vacuum-pressed to make the semi-cured phosphor completely adhere to the surface and sides of the flip-chip LED.

[0009] The pre-cured fluorescent sheet that has been vacuum-pressed is cured at a second preset temperature for a second preset time to complete the second curing and obtain the cured finished product.

[0010] The cured product is then encapsulated with transparent adhesive to obtain an LED encapsulated device.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The LED packaging device preparation method provided by the present invention mixes encapsulating silicone with phosphor to form a film, and then uses low temperature and short time for one-time curing to form a semi-cured phosphor film. This quickly transforms the phosphor-containing film from a liquid state to a semi-solid state, achieving one-time curing. In this one-time curing, only coupling reaction occurs, and the basic structure is built in advance, allowing the phosphor to be initially fixed in the semi-cured phosphor film, reducing the risk of color point shift in the later stage, and avoiding phosphor agglomeration and displacement or disordered phosphor distribution and silicone cross-linking in subsequent transfer processes, which would cause uneven phosphor distribution and unstable adhesive amount. Then, through high temperature and long time for secondary curing, the encapsulating silicone components are cross-linked, improving the bonding force between the semi-cured phosphor film and the flip-chip LED and the support, forming a dense and stable structure. This allows for more complete excitation coupling between the phosphor and the flip-chip LED, improving brightness and concentration, thereby solving the technical problems of poor adhesive amount stability and uneven phosphor distribution in LED packaging devices in the prior art, which lead to a decrease in brightness and concentration.

[0012] According to one aspect of the above technical solution, the encapsulating silicone includes vinyl silicone resin and polyurethane resin, wherein the polyurethane groups in the polyurethane resin have a molecular weight of 2000~10000, and the mass of the polyurethane resin is 30%~50% of the mass of the vinyl silicone resin.

[0013] According to one aspect of the above technical solution, the phosphor in the membrane has a mass percentage of 20% to 80%.

[0014] According to one aspect of the above technical solution, the preset thickness is 80μm~120μm.

[0015] According to one aspect of the above technical solution, the first preset temperature is 80℃~120℃, the first preset time is 2min~5min, and the refractive index of the semi-cured fluorescent sheet is 1.50~1.52.

[0016] According to one aspect of the above technical solution, the semi-cured phosphor sheet is square in shape, and the side length of the semi-cured phosphor sheet is twice the height of the flip-chip LED chip plus the sum of the side length.

[0017] According to one aspect of the above technical solution, the second preset temperature is 150℃~170℃, and the second preset time is 120min~150min.

[0018] According to one aspect of the above technical solution, the transparent adhesive is made of vinyl phenyl silicone resin, and the refractive index of the transparent adhesive is 1.47~1.49.

[0019] A second aspect of the present invention is to provide an LED packaging device, the LED packaging device being prepared by the above-described method for preparing an LED packaging device.

[0020] A third aspect of the present invention is to provide an application of the LED packaging device described above in the fields of display, backlighting, and lighting. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram illustrating the fabrication method of an LED packaging device according to an embodiment of the present invention.

[0023] Component symbol explanation in the attached diagram:

[0024] 1. Support bracket, 2. Flip-chip LED, 3. Film, 4. Transparent adhesive, 30. Semi-cured fluorescent sheet. Detailed Implementation

[0025] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0027] Please see Figure 1 The figure shows a method for preparing an LED packaging device according to an embodiment of the present invention. The preparation method includes steps S10 to S14.

[0028] Step S10: Mix the encapsulating silicone and phosphor according to a preset ratio, and then use a film coating machine to prepare a film of a preset thickness;

[0029] The encapsulating silicone comprises vinyl silicone resin and polyurethane resin, wherein the polyurethane groups in the polyurethane resin have a molecular weight of 2000~10000, and the mass of the polyurethane resin is 30%~50% of the mass of the vinyl silicone resin.

[0030] It should be noted that modification is achieved by introducing polyurethane groups to regulate the groups (phenyl, methyl, and other organic groups) on the organosilicon chains of the vinyl silicone resin, thereby achieving one-time curing. This one-time curing involves only coupling reactions. By mixing the phosphor with the encapsulating silicone and semi-curing it into a film, the uniformity of phosphor distribution can be effectively improved.

[0031] Furthermore, in the diaphragm 3, the phosphor's mass percentage is 20% to 80%. Too much or too little phosphor will affect the position of the CIE color point, causing it to deviate from the target area and resulting in the white light color not meeting the standard.

[0032] CIE stands for International Commission on Illumination, an internationally authoritative organization for setting lighting and color standards. LED-related products must pass the CIE standard to evaluate their color performance. This involves using the CIE chromaticity diagram to determine the white light color and whether it meets the color temperature and color difference requirements of the lighting and display scenarios.

[0033] Furthermore, the preset thickness of the membrane 3 is 80μm~120μm.

[0034] Step S11: The film is cured at a first preset temperature for a first preset time to complete one curing process and obtain a semi-cured fluorescent sheet.

[0035] Furthermore, the first preset temperature is 80℃~120℃, the first preset time is 2min~5min, and the refractive index of the semi-cured fluorescent sheet 30 is 1.50~1.52.

[0036] It should be noted that through a single low-temperature curing process, only a coupling reaction occurs to form a semi-cured phosphor sheet 30. This single curing process mainly serves to shape the film 3, enabling subsequent uniform and stable transfer onto the chip. It effectively solves the problem of unstable adhesive volume during dispensing. At the same time, it allows the phosphor to be initially fixed in the semi-cured phosphor sheet 30, making it less prone to agglomeration and displacement in subsequent processes. This ensures the spectral stability of the emitted light after excitation, helps the CIE color point to approach the target area, improves the consistency of white light color, and solves the problem of uneven distribution of phosphor in the phosphor adhesive.

[0037] In addition, by curing at low temperature in one step, the phosphor-containing film 3 can be quickly transformed from a liquid state to a semi-solid state, providing a stable form for subsequent processes such as bonding flip-chip LEDs 2, facilitating precise control of the thickness and size of the film 3, and ensuring the compatibility between the semi-cured phosphor sheet 30 and the flip-chip LED 2.

[0038] Preferably, the semi-cured phosphor sheet 30 is square in shape, and the side length of the semi-cured phosphor sheet 30 is twice the height of the flip-chip LED chip 2 plus the sum of the side length. The semi-cured phosphor sheet 30 is easy to process, and semi-cured phosphor sheets 30 of preset size can be rolled to fit the side of the flip-chip LED chip 2, creating conditions for precise bonding and cross-linking during secondary curing.

[0039] Understandably, the size of the semi-cured phosphor sheet 30 is set according to the length, width and height of the flip-chip LED chip 2. If the size is too large, it will cause stacking and wrinkles; if the size is too small, it will not be able to completely cover the entire side, resulting in the side light source leaking out.

[0040] Step S12: Transfer the prepreg phosphor to the flip-chip that has been die-bonded in the support, and vacuum press it to make the prepreg phosphor completely adhere to the surface and sides of the flip-chip.

[0041] Specifically, the vacuum pressure conditions are: -0.8atm to 1atm, temperature 150℃ to 170℃, and time 180s to 300s.

[0042] Understandably, the semi-cured phosphor sheet 30 has a certain degree of plasticity. During vacuum pressing, under the assistance of pressure and vacuum environment, the semi-cured phosphor sheet 30 can closely adhere to the complex structure on the side of the flip-chip LED chip 2, fill the tiny gaps, and create a uniform, bubble-free interface for the complexation reaction of secondary curing. This ensures the subsequent optical coupling effect, making the light emission of the flip-chip LED chip 2 more fully coupled with the phosphor, resulting in less light scattering, higher excitation efficiency, more concentrated and brighter light emission, directly optimizing the CIE color point stability and improving the quality of white light.

[0043] Step S13: The pre-cured fluorescent sheet that has been vacuum-pressed is cured at a second preset temperature for a second preset time to complete the second curing and obtain the cured finished product.

[0044] Furthermore, the second preset temperature is 150℃~170℃, and the second preset time is 120min~150min.

[0045] It should be noted that the high-temperature, long-term curing reaction allows the polyurethane-modified vinyl silicone resin to fully cross-link, improving the bonding force between the semi-cured phosphor sheet 30 and the flip-chip LED chip 2 and the support 1, forming a dense and stable structure, enhancing the mechanical strength and resistance to environmental interference of the LED packaging device, extending the service life of the LED packaging device, and improving the long-term reliability of the LED packaging device.

[0046] Step S14: The cured product is encapsulated with transparent adhesive to obtain an LED encapsulated device.

[0047] Furthermore, the transparent adhesive 4 is made of vinyl phenyl silicone resin, and the refractive index of the transparent adhesive 4 is 1.47~1.49.

[0048] It should be noted that the low-refractive-index transparent adhesive 4, as the outer layer, works in conjunction with the inner high-refractive-index semi-cured phosphor sheet 30. By guiding the light emission direction through the refractive index gradient and controlling the light angle, it makes it easier for light emitted at both large and small angles to escape. This compensates for the insufficient control of light at different angles by a single layer of transparent adhesive 4, creating a more efficient light extraction path. Furthermore, the flip-chip LED 2 (such as a blue-violet LED chip) has a high refractive index. Light traveling from the flip-chip LED 2 to the transparent adhesive 4 and then to the air is prone to total internal reflection due to the refractive index difference, causing the light to be trapped within the flip-chip LED 2. The low-refractive-index transparent adhesive 4 (which is compatible with the refractive indices of the flip-chip LED 2 and air) reduces the refractive index difference between the flip-chip LED 2, transparent adhesive 4, and air, lowering the probability of total internal reflection and allowing more light to escape from the sides and surface of the flip-chip LED 2, improving light extraction efficiency, especially significantly optimizing light emission from the sides of the flip-chip LED 2.

[0049] Accordingly, the present invention also provides an LED packaging device, which is prepared by the above-described method for preparing an LED packaging device.

[0050] In addition, the present invention also provides an application of the LED packaging device described above in the fields of display, backlighting, and lighting.

[0051] The technical solution of the present invention will now be described in detail with reference to specific embodiments.

[0052] Example 1

[0053] The first embodiment of the present invention provides a method for preparing an LED packaged device, the method comprising steps S10-S14.

[0054] Step S10: Mix the encapsulating silicone and phosphor according to a preset ratio, and then use a film coating machine to prepare a film of a preset thickness;

[0055] The encapsulating silicone comprises vinyl silicone resin and polyurethane resin, wherein the polyurethane groups in the polyurethane resin have a molecular weight of 6000, and the mass of the polyurethane resin is 40% of the mass of the vinyl silicone resin.

[0056] Furthermore, in the membrane, the phosphor has a mass percentage of 50%.

[0057] Furthermore, the preset thickness of the membrane is 100 μm.

[0058] Step S11: The film is cured at a first preset temperature for a first preset time to complete one curing process and obtain a semi-cured fluorescent sheet.

[0059] Furthermore, the first preset temperature is 100℃, the first preset time is 3min, and the refractive index of the semi-cured fluorescent sheet is 1.50~1.52.

[0060] Preferably, the semi-cured phosphor sheet is square in shape, and the side length of the semi-cured phosphor sheet is the sum of twice the height of the flip-chip LED and the side length.

[0061] Step S12: Transfer the prepreg phosphor to the flip-chip that has been die-bonded in the support, and vacuum press it to make the prepreg phosphor completely adhere to the surface and sides of the flip-chip.

[0062] Specifically, the vacuum settling conditions are: -0.9 atm, temperature 160℃, and time 240s.

[0063] Step S13: The pre-cured fluorescent sheet that has been vacuum-pressed is cured at a second preset temperature for a second preset time to complete the second curing and obtain the cured finished product.

[0064] Furthermore, the second preset temperature is 160°C, and the second preset time is 140 min.

[0065] Step S14: The cured product is encapsulated with transparent adhesive to obtain an LED encapsulated device.

[0066] Furthermore, the transparent adhesive is made of vinyl phenyl silicone resin, and the refractive index of the transparent adhesive is 1.47~1.49.

[0067] Example 2

[0068] The second embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0069] The preset thickness of the membrane is 80 μm.

[0070] Example 3

[0071] The third embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0072] The preset thickness of the membrane is 120 μm.

[0073] Example 4

[0074] The fourth embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0075] The first preset temperature is 80℃.

[0076] Example 5

[0077] The fifth embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0078] The first preset temperature is 120℃.

[0079] Example 6

[0080] The sixth embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0081] The first preset time is 2 minutes.

[0082] Example 7

[0083] The seventh embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0084] The first preset time is 4 minutes.

[0085] Example 8

[0086] The eighth embodiment of the present invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this embodiment and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0087] The first preset time is 5 minutes.

[0088] Comparative Example 1

[0089] The first comparative example of this invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this comparative example and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0090] The process involves dispensing adhesive for encapsulation, followed by curing.

[0091] Comparative Example 2

[0092] The second comparative example of this invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this comparative example and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0093] The preset thickness of the membrane is 60 μm.

[0094] Comparative Example 3

[0095] The third comparative example of this invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this comparative example and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0096] The preset thickness of the membrane is 140 μm.

[0097] Comparative Example 4

[0098] The fourth comparative example of this invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this comparative example and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0099] The first preset temperature is 60℃.

[0100] Comparative Example 5

[0101] The fourth comparative example of this invention provides a method for fabricating an LED packaged device. The difference between the method for fabricating the LED packaged device in this comparative example and the method for fabricating the LED packaged device in the first embodiment is as follows:

[0102] The first preset time is 1 minute.

[0103] Please refer to Table 1 below, which shows the parameters corresponding to the above embodiments and comparative examples of the present invention.

[0104] Table 1:

[0105]

[0106] Among them, the 3rd order region refers to the set of LED packaged devices whose color coordinates fall within the 3rd order MacAdam ellipse. This means that the color tolerance of this batch of LED packaged devices is controlled within the 3rd order standard. The color difference is almost imperceptible to the human eye and is a key indicator of color consistency after LED packaging. In addition, the brightness improvement rate is calculated based on the brightness of Comparative Example 1.

[0107] As can be seen from the data comparison in Table 1, the two-stage curing process of this embodiment forms a stable and uniform phosphor sheet bonded to the flip-chip, which can effectively improve the brightness and concentration of the LED package device.

[0108] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0109] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for fabricating an LED packaged device, characterized in that, The preparation method includes: Encapsulating silicone and phosphor are mixed in a preset ratio, and then a film of a preset thickness is prepared by a film coating machine. The encapsulating silicone includes vinyl silicone resin and polyurethane resin. The polyurethane groups in the polyurethane resin have a molecular weight of 2000~10000. The mass of the polyurethane resin is 30%~50% of the mass of the vinyl silicone resin. In the film, the mass percentage of phosphor is 20%~80%, and the preset thickness is 80μm~120μm. The film is cured at a first preset temperature for a first preset time to complete one curing cycle, resulting in a semi-cured fluorescent sheet. The first preset temperature is 80℃~120℃, the first preset time is 2min~5min, and the refractive index of the semi-cured fluorescent sheet is 1.50~1.

52. The semi-cured phosphor is transferred to the flip-chip LED that has been die-bonded in the support, and vacuum-pressed to make the semi-cured phosphor completely adhere to the surface and sides of the flip-chip LED. The pre-cured fluorescent sheet that has been vacuum-pressed is cured at a second preset temperature for a second preset time to complete the second curing and obtain the cured finished product. The second preset temperature is 150℃~170℃ and the second preset time is 120min~150min. The cured product is encapsulated with transparent adhesive to obtain an LED encapsulation device. The transparent adhesive is made of vinyl phenyl silicone resin and has a refractive index of 1.47 to 1.

49.

2. The method for preparing an LED packaged device according to claim 1, characterized in that, The semi-cured phosphor sheet is square in shape, and the side length of the semi-cured phosphor sheet is twice the height of the flip-chip LED chip plus the sum of the side length.

3. An LED packaging device, characterized in that, The LED packaging device is prepared by the method for preparing the LED packaging device according to any one of claims 1-2.

4. An application of the LED packaging device as described in claim 3 in the fields of display, backlighting, and lighting.

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