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Fluorescent powder coating liquid of white light emitting diode as well as preparation method and coating method thereof

A technology of light-emitting diodes and phosphors, which is applied in the direction of luminescent paints, coatings, and devices for coating liquid on the surface, which can solve problems such as phosphor damage, color drift, and increased distance, and improve reliability and stability. , Reduce thermal quenching, slow down the effect of precipitation

Active Publication Date: 2013-11-20
FOSHAN NATIONSTAR OPTOELECTRONICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The above-mentioned traditional phosphor coating methods are prone to the following problems: 1. Organic colloids (such as epoxy and silicone) cannot effectively protect against ultraviolet radiation, resulting in damage to the phosphor, such as aging attenuation, color drift, etc.
The literature "Research on Phosphor Powder Aging in White LED" (Foshan Institute of Science and Technology (Natural Science Edition), 2007, 25(4), 6-8) analyzed and confirmed that the attenuation of the conversion rate of phosphor powder under thermal effect and current effect is One of the important factors affecting the aging of white light LED; patent CN201062757Y (Zhu Jianping) is to change the phosphor layer to the lens so as to increase the distance between the phosphor layer and the chip to avoid the attenuation and aging of the phosphor; 2. During the coating process, rapid sedimentation is caused by the large density difference between the phosphor powder and the organic colloid, and the process needs to constantly stir the mixed liquid of the phosphor powder and the glue solution to alleviate this tendency; 3. During the use of the LED, the non-crystalline organic polymer Thermal motion in the form of rotation, movement and orientation of the chain segment relative to other parts of the molecule will lead to further migration, sedimentation or agglomeration of the phosphor, resulting in the drift of the LED color

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: The phosphor coating solution is composed of silica sol, phosphor powder and deionized water with weight percentages of 60%, 35% and 5% respectively. Among them, the silica sol adopts inorganic compound nano silica sol; the function of deionized water is to adjust the viscosity of the coating liquid. In other embodiments, distilled water can be used instead of deionized water; in further embodiments, reinforcing agents, plasticizers and dispersants can also be added as additives.

[0018] The silica sol in this embodiment belongs to nano-gel, and the nano-glue itself has a "coating" effect on the phosphor, which reduces the damage of ultraviolet radiation to the phosphor, reduces the thermal quenchability of the phosphor, and thereby reduces the phosphor The attenuation and color drift of light-emitting diodes and improve the aging resistance of light-emitting diodes. The phosphor coating solution for white light emitting diodes uses an inorganic binder, bec...

Embodiment 2

[0020] Example 2: At room temperature, slowly pour 60% neutral silica sol, 5% deionized water, and other additives (such as strengthening agents, plasticizers and dispersants) into a ball mill containing 35% phosphor In the tank, add a certain amount of grinding balls to mix the mill. The weight ratio of agate balls with diameters of φ6, φ10, and φ15 is determined according to the required particle size. The preferred ratio in this example is 2:1:1. The speed of the ball mill is 90n / min, about 4h. The silica sol in this embodiment is an inorganic polymer after being cured, does not generate segmental thermal motion, and has better compatibility with inorganic phosphors. Therefore, the reliability and stability of the LED are improved.

[0021] The embodiment of the present invention provides a coating method based on the above-mentioned white light emitting diode phosphor coating liquid. The coating liquid is added to the liquid precise quantitative dispensing device to dispens...

Embodiment 3

[0022] Example 3: Add the prepared coating solution to the liquid precise quantitative dispensing device to dispense and coat the light-emitting diode chip. The coated chip is placed in an oven at 100-150°C for 20-30 minutes to let the solvent evaporate , And then carry out the resin encapsulation process. Among them, an oven curing condition with a temperature of 120°C and a time of 20-30 minutes is a preferred solution. The use of the coating solution has a higher refractive index than traditional organic packaging materials, and can further improve the light extraction efficiency of the packaging device.

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Abstract

The invention provides a fluorescent powder coating liquid of a white light emitting diode as well as a preparation method and a coating method thereof, and the coating liquid is characterized by comprising fluorescent powder and a binder, wherein the binder is an inorganic compound-nano silica sol; a solvent is added according to the requirements; and the coating liquid is prepared by adopting a mixing ball mill in the preparation method. The fluorescent powder coating liquid has the advantages that the membrane enveloping effect on the fluorescent powder is realized by utilizing the nano silica sol; the damage of the harmful ultraviolet radiation on the fluorescent powder is reduced; and the hot quenching property of the fluorescent powder is lowered so that the attenuation of the fluorescent powder and the color bleaching of the light emitting diode are reduced, and the aging resistance property of the light emitting diode is improved.

Description

Technical field [0001] The invention relates to the technical field of white light emitting diode packaging, in particular to a method for configuring a white light emitting diode phosphor coating liquid. Background technique [0002] Light-emitting diodes (LED) have the advantages of high efficiency, energy saving, and environmental protection. The technological advancement of white LEDs has created conditions for LEDs to enter the field of general lighting. LEDs are generally regarded by the industry as the main lighting source in the 21st century. Technically, the realization of white light LED mainly includes: using RGB (red, green, blue) three primary colors, multiple chips or multiple devices to emit light and mixing them into white; coating RGB phosphors on UV chips, and using violet light to excite the phosphors The three primary colors are mixed to form white light, or the blue LED chip is coated with YAG (yttrium aluminum garnet) phosphor, and the blue light emitted by...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09D1/00C09D5/22C09D7/12B05C9/14H01L33/00
Inventor 余彬海李绪锋李程陈灿伟
Owner FOSHAN NATIONSTAR OPTOELECTRONICS CO LTD
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