An improvement method of uniformity of color temperature of White LED

A new way of phosphor coating is presented to realize high power white light LED, which makes the mixture of phosphor and silica coating inside of the package lens. Then the lens is inverted, so that the mixture of phosphors and silica flow from the center to the around of the lens, the uniform thickness of the phosphor layer can be obtained after solidification and encapsulation. According to this new way, a white LED sample is produced. The performance of the sample is tested and compared with the sample produced under the traditional phosphor coating. The results show that the white light LED manufactured by new phosphors coating technique has significant improvement in stability and homogeneity of the correlated color temperature.

Realization of high-power white LED at present is mainly using blue LED chip with yellow phosphor light conversion that is directly on the chip surface coated with phosphor powder and silica gel mixture. Using the traditional method of fluorescent powder coating, due to the thickness of phosphor powder coated on the surface of the chip is hard to control, the white light correlated color temperature distribution is very difficult to achieve uniform, Phosphor powder clingy chip heat source, and affect the product performance. To solve the defects of correlated color temperature , you must change the way of coating phosphor powder, make phosphor powder layer thickness as the same, so can get the uniformity of correlated color temperature distribution.