Packaging process for white light-emitting diodes (LEDs)

Abstract

The invention discloses a packaging process for white light-emitting diodes (LEDs). The packaging process comprises the following steps of blending silica gel A, silica gel B, a brightening agent, an anti-settling agent, aluminate phosphor and nitride phosphor according to a mass proportion of 0.4:1.6:0.01:0.01:0.73:0.08 to prepare fluorescent gel, wherein the model number of the silica gel A is 1520A, and the model number of the silica gel B is 1520B; dispensing the prepared fluorescent gel into blue LED chips to be packaged, placing the blue LED chips to be packaged on the inner wall of a revolving drum of a centrifugal machine in batches, and revolving the revolving drum for 160 to 200 seconds at revolving speed of 1,800 to 2,200 revolutions per minute; and placing the centrifugally precipitated LEDs into an oven, baking the LEDs for 50 to 70 minutes at 70 to 90 DEG C, and baking the LEDs for 110 to 130 minutes at 140 to 160 DEG C. The emission wavelengths of the LED chips are matched with the excitation wavelength of the phosphor, so that an optimal color rendering property is achieved; a refractive index after the silica gel A and the silica gel B are blended can reach 1.53, so that the luminous efficiency can be improved, and radiation can be improved; a centrifugal precipitation mode is adopted, the fluorescent gel can be precipitated at the bottom of an LED support, and residual light on the lateral surfaces of the chips can be totally reflected, so that the luminous efficiency can be improved by 5 to 10 percent; and the spectroscopical BIN-based targeting rate of a centrifugal precipitation process is greatly increased.

Description

technical field [0001] The invention relates to an LED encapsulation process, in particular to a white LED encapsulation process. Background technique [0002] For white LEDs, brightness is its most important performance parameter. In the packaging of white light LEDs, the deployment and curing of fluorescent glue plays an important role in the brightness and various optical indicators of LEDs. In the traditional LED packaging method, the color rendering of white light LEDs is poor due to the formula and component ratio of the fluorescent glue, the matching of the wavelength of the phosphor powder and the wavelength of the LED chip, and the matching of the phosphor and silica gel. If the refractive index difference between the LED chip and the fluorescent glue is too large, because the LED chip material has a much larger refractive index than the surrounding medium, a large part of the photons inside the chip cannot smoothly overflow the interface, and the interface between...

AI Technical Summary

Problems solved by technology

In the traditional LED packaging method, the color rendering of white light LEDs is poor due to the formula and component ratio of the fluorescent glue, the matching of the wavelength of the phosphor powder and the wavelength of the LED chip, and the matching of the phosphor and silica gel. If the refractive index difference between the LED chip and the fluorescent glue is too large, because the LED chip material has a much larger refractive index than the surrounding medium, a large part of the photons inside the chip cannot smoothly overflow the interface, and the interface between the chip and the medium During total reflection, the photons return to the inside of the chip and are finally absorbed by the chip material or substrate for multiple internal reflections, and become heat in the form of lattice vibration, which increases the junction temperature and greatly reduces the light extraction efficiency.

In the curing process of fluorescent glue, many packaging companies directly enter the baking process after dispensing glue. This method leads to: 1. Due to the uneven distribution of phosphor powder, the color consistency of the LED is poor, the brightness is uneven, and the product yield is low. ; 2. Because the phosphor powder is far away from the surface of the chip, the luminous efficiency of the LED cannot be well stimulated; 3. Because there are many fluorescent glue dead spots on the bracket on the side of the chip, the photons on the side of the chip are lost by about 10%-20%

Of course, there are also a small number of packaging manufacturers who place the glue for about 90 minutes before baking during the packaging process. Although this improves the yield rate of the color area to a certain extent, it is difficult to control the process during the production process, and it is easily affected by room temperature and phosphors. Due to the impact of particles, a little carelessness will cause bad color areas in batches

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