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White-light LED package structure with prefabricated fluorescent powder film

A technology of LED encapsulation and encapsulation structure, applied in the direction of light sources, lighting devices, point light sources, etc., can solve the problems of incomplete light chromaticity, difficulty in phosphor concentration, and influence on LED life, so as to ensure high consistency and manufacture The process is simple and the effect of preventing blue light leakage

Active Publication Date: 2009-09-02
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] During the above-mentioned LED packaging process, there are three key problems in the phosphor powder coating: first, it is difficult to maintain a high degree of uniformity in the phosphor powder concentration from beginning to end, because the phosphor powder A certain particle size is maintained in the silica gel, and the phosphor has a certain weight, and its density is much higher than that of silica gel. Therefore, although the silica gel is relatively viscous, the phosphor will still slowly settle in it, and the time for degassing Longer, indirectly promotes the precipitation of phosphor powder, so when dispensing glue, the concentration of phosphor powder in the glue dispensed at the beginning is higher, and the concentration is lower as it goes, which leads to different batches or even the same The chromaticity of the LEDs manufactured in batches is not exactly the same. Finally, the factory must classify the manufactured LEDs according to parameters such as color error or color temperature.
; Second, the thickness of the dispensing glue on a single chip is difficult to be consistent. Since the glue dispensed by the dispensing machine is approximately spherical each time, the cured phosphor coating must be thick in the middle and thin around, and finally the LED is packaged. The light chromaticity must be inconsistent from the middle and the surroundings, the middle is yellowish, and the surroundings are blue; the third is the problem of luminous attenuation caused by the heating of the phosphor powder, because the current LED packaging process is to directly dispense the mixture of phosphor powder and silica gel to the chip. On the other hand, when the chip is working, it will emit a lot of heat, which will cause the temperature around the chip to rise rapidly. As a result, the luminous efficiency of the phosphor will continue to decline due to heat, which will directly affect the life of the LED.

Method used

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  • White-light LED package structure with prefabricated fluorescent powder film

Examples

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Effect test

Embodiment 1

[0021] Embodiment 1. take by weighing 3g YAG: Ce 3+ Fluorescent powder, 3g of silica gel, mixed evenly, coated with a 0.2mm thick film by screen printing, put into a vacuum desiccator and heated and cured at 120°C for 1 hour, took out the film, and cut it into small discs with a diameter of 3mm. Coat a little silica gel on the inner side of the optical lens, stick the prefabricated fluorescent powder and small pieces of silica gel on it, put it into a vacuum desiccator and heat and cure at 120°C for 30 minutes, and set it aside. Bond a chip in the middle of the bottom of the bracket that is hollowed out in the middle, solder the circuit, and then fix the prepared optical lens with phosphor powder and silica gel prefabricated film on the bracket, inject silica gel into the middle gap, and put the whole into a vacuum Heating in a desiccator at 120°C for 1 hour and curing, the finished white LED lamp can be obtained.

Embodiment 2

[0022] Embodiment 2. Take by weighing 1g YAG: Ce 3+ Phosphor powder and 4g of silica gel were mixed evenly, coated with a 0.3mm thick film by screen printing, put into a vacuum desiccator and heated and cured at 150°C for 1 hour, took out the film, and cut into small pieces of 2×2mm. Coat a little silica gel on the inner side of the optical lens, stick the prefabricated fluorescent powder and small pieces of silica gel on it, put it into a vacuum desiccator and heat and cure at 120°C for 30 minutes, and set it aside. Bond the chip in the middle of the bottom of the hollow bracket, solder the circuit, and then fix the prepared optical lens on the bracket with phosphor powder and silica gel prefabricated film, inject silica gel into the middle gap, and put the whole into a vacuum Heating in a desiccator at 120°C for 2 hours and curing, the finished white LED lamp can be obtained.

Embodiment 3

[0023] Embodiment 3. Take by weighing 0.5gYAG: Ce 3+ Phosphor powder, 1gLiEuW 2 o 8 Phosphor powder and 2g of epoxy resin are mixed evenly, coated with a 0.4mm thick film by screen printing, put into a vacuum desiccator at 100°C for heating and curing for 2 hours, take out the film, and cut into small pieces of 2×2mm. Coat a little epoxy resin on the inner side of the optical lens, stick the prefabricated fluorescent powder and the small piece of epoxy resin on it, put it into a vacuum desiccator and heat and cure at 120°C for 30 minutes, and set it aside. Bond the chip in the middle of the bottom of the hollow bracket, solder the circuit, then fix the prepared optical lens with phosphor powder and epoxy resin prefabricated film on the bracket, inject epoxy resin into the middle gap, and place this The whole is put into a vacuum desiccator and heated at 120°C for 2 hours to cure, and the finished white LED can be obtained.

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Abstract

The invention provides a white-light LED package structure with a prefabricated fluorescent powder film, which consists of an optical lens 1, a fluorescent powder and caking agent prefabricated film layer 2, a chip 5 and a support with a hollow center 6, wherein the fluorescent powder and caking agent prefabricated film layer 2 is glued on the plane of the optical lens 1; the chip 5 is arranged on a central position on the bottom of the support with the hollow center 6; the optical lens 1 glued with the fluorescent powder and caking agent prefabricated film layer 2 and the support 6 are fixed together; and the caking agent is filled in the middle clearance between the optical lens 1 and the support 6. A white-light LED manufactured by the package structure improves the light-emitting consistency greatly, has stable optical parameters, shortens difference in the same batch or different batches greatly, and can improve the production efficiency. Because the fluorescent powder does not contact the chip directly, luminescence decay of the fluorescent powder caused by heating of the chip can be obviously reduced.

Description

technical field [0001] The invention relates to a white light LED packaging structure and a preparation method thereof, belonging to the field of solid-state lighting. Background technique [0002] As a new type of solid light source, LED (Light Emitting Diode) develops rapidly because of its small size, fast response, good shock resistance, long life, especially energy saving and environmental protection. In recent years, it has been widely used in large-screen display, traffic signal lights, landscape lighting, street lighting and other fields. [0003] Due to technological development, the current mainstream white light LED manufacturing method is blue light chip + yellow phosphor powder. The specific process is: first fix the chip on the bracket and connect the circuit; After mixing the two, put them in a vacuum dryer to remove air bubbles (it takes at least 30 minutes), and then apply the mixture of phosphor and silica gel to the chip (also called dispensing), then hea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L33/00F21Y101/02F21Y115/10
Inventor 王海波张瑞西黄如喜印琰林海凤
Owner NANJING UNIV OF TECH