Japan's chemical industry, high temperature resistant green fluorescent material to achieve practical level, can simplify the LED backlight light cooling mechanism

The chemical industry of Japan has made the green fluorescent material of beta -SiAlON reach the practical level. High color white LED for use in combination with green and red fluorescent materials on blue LED. Compared with common silicate green fluorescent materials, the luminescence intensity decreases with increasing temperature (Figure 1). The product is expected to be used in LCD TV backlight with white LED.

White LED in a long period of time when the light is "above the temperature of the chip will reach 100 ~ 150 DEG C" (Electrical and chemical industry). If it is the use of silicate green fluorescent material of white LED, there will be a decline in the intensity of green light, color balance is damaged. Therefore, for LCD TVs, such as the LED backlight, the full cooling mechanism is essential.

And the green fluorescent material, the strong covalent bond between atoms, the temperature has excellent structural stability, so the intensity of the luminescence is smaller. If it is a high temperature color change is also very small white LED, can simplify the backlight heat sink. Although the price of silicate materials "several times" (Vice Minister of electrical chemical industry electronic materials business department of electronic materials division of electronic component Sawada Junichi), but through the use of the development of the white LED based, will help reduce the cost of the final product.

The fluorescent material has been sold since October 2009. In addition, the company also decided on the production and development of products of the factory, Fukuoka County Tian Mou equipment investment, "in 2010, starting a new pot" (the executive director of the company, electronic materials business department of Electronic Materials Division Secretary Yamamoto).

SHARP is expected to assist in the development of the first use of the material. For the material, the Japan Institute of materials and materials related patents, and the chemical industry and the organization of the existence of cooperative relations, it is free to sell. "Will launch a large-scale sales" (chemical industry), is expected to reach the first sales of billions of yen.

The difficulty of the material lies in the luminous intensity at room temperature. The luminescence intensity is slightly lower than that of silicate materials. The company said that the future will strive to improve through the same level of improvement. The fluorescent material in the P type silicon nitride (Si3N4) Si replacement crystallization into Al, part of N replaced O materials (matrix crystallization), responsible for the luminescence of europium added (Eu) and Ce (Se) made of rare earth elements etc.. Using the bond force of rare earth ions (Enomoto Hideyuki, the Basic Research Institute of the Central Research Institute), to fine tune the rare earth ions around the matrix, can enhance the intensity of luminescence.

The development of beta -SiAlON green fluorescent materials (Photography: Electrical and chemical industry)

Figure 1: comparison of the temperature characteristics of -SiAlON green fluorescent material and common silicate green fluorescent material at high temperature. The luminescence intensity of -SiAlON green fluorescent material is not easy to drop at high temperature.