China white LED break patent barrier

China successes in developing a new powder for producing white light on blue LED.

Title:一种氮氧化合物发光材料及其制法以及由其制成的照明或显示光源

Abstract:一种氮氧化合物发光材料，其分子式为A1-xByOzNw:Eux，其中A为碱金属、碱土金属、 稀土金属中的一种或几种；B为III-V族元素中的一种或几种且至少含有Si；0≤x≤1.0； 1.0≤y≤2.0；1.0≤z≤2.0；1.0≤w≤3.0。该发光材料被紫外、近紫外或蓝光等 激发光源如LED激发时，能发射波长在470-570nm的蓝绿色，绿色，或黄色光。本发明还 涉及该氮氧化合物发光材料的制备方法。本发明的发光材料具有激发波长范围宽、高效、稳 定的特点，制备方法简单、易于批量生产、无污染。用本发明的发光材料配合紫外、近紫 外或蓝光LED以及其它发光材料如红色荧光粉可制得新型白光LED光源。

Producing white light source:

• 3 LED(Red, Green, Blue) mix on chip
• Powder in blue LED (converts blue ray into yellow, and then mixes them, equivalently 550nm)

     InGaN blue LED and powder is cheaper and smaller method, adopted more commonly in market. But...........

Patent

• YAG: Y3Al5O12: Ce

    Japan own the most of patents about LED and major slice of market share. Nichia's YAG powder is regarded as the most efficient method of white light conversion. (Thanks to Shuji Nakamura, 中村修二 ; Because he insisted in YAG powder, even though Nichia suspend his research. After leaving Nichia, now he is chair of Cree, USA) http://en.wikipedia.org/wiki/Shuji_Nakamura 

• TAG: Tb3Al5O12:Ce

     TAG is developed by OSRAM, but still can't escape from the claim of Nichia's YAG. But Osram and Nichia had cross licence agreement in 2002.

Different compound

     China, Yuji Science & Technology Co. supports a new chemical compound - oxide of nitrogen, avoiding YAG, TAG ....powder patents. This is very different from others phosphor, no matter in main component or derivatives.  

Efficiency issue

     Dr. Wang HaiSong, vice chief engineer of Science & Technology Development Co., Ltd., shows very much on the space of Beijing: “Though the phosphor powder present efficiency of the oxides of nitrogen is still lower than aluminate and silicate phosphor powder, but developing history of it only 5-6 year also, future still greatly development space. Review aluminate, can say to ultimate attainment in its development, and it is impossible for it to make the white light LED of required high warm white of European market. ”