摘要
用GaN基大功率蓝光LED芯片作为激发光源,分别用荧光粉转换法和红光LED补偿法制备了不同相关色温及显色指数的白光LED。对器件的发光特性研究表明,采用蓝光LED芯片激发单一黄色荧光粉,虽可以获得光通量和发光效率较高的白光LED,但其色温较高,显色性较差;在黄色荧光粉中添加红色荧光粉,由于光谱中红色成分的增加,可降低器件的色温,并提高器件的显色性,但由于目前红色荧光粉的转换效率较低,致使器件的整体发光效率不高;采用蓝光LED芯片激发黄色荧光粉,同时用红光LED进行补偿,通过调整蓝光和红光LED芯片的工作电流以及荧光粉的用量,可获得低色温和高显色性白光LED,而且整体发光效率较高。
GaN-based blue LED chips were used as exciting light source, high-power white LEDs with different correlative color temperature （Tc） and rendering index （Ra） were fabricated through phosphor conversion and red LED compensation. The luminescence characteristics of white LED devices ,such as emission spectrum, chromaticity coordinate, R, ,luminous flux （φ）, luminous efficiency （η）, and their changes at various forward current （IF） and content of red phosphor （C） were studied. Results indicate that, combining blue LED chip and single YAG：Ce^3＋ yellow phosphor,white LEDs with high φ and η could be obtained,but Tc of these devices is relatively high, and Ra is very low. Adding red phosphor into yellow phosphor, the emergence of red light in the emission spectra of these devices results in Tc reduces, and R aincreases. However, because the light-conversion efficiency of red phosphor is very low at present,the luminous efficiency of these white LEDs is dissatisfactory. Adopting blue LED chip to excite yellow phosphor,at the same time red LED chips are used to compensate red light in emission spectrum,white LEDs with low Tc and high Ra would be obtained by adjusting the work current of blue and red LED chips and the dosage of phosphor.
出处
《光电子．激光》
EI
CAS
CSCD
北大核心
2006年第12期1422-1426,共5页
Journal of Optoelectronics·Laser
基金
国家"十五"科技攻关计划重大资助项目(2003BA316A01-01-02)
深圳市科技计划资助项目
关键词
大功率白光LED
低色温
高显色性
发光特性
High-power white LEDs
low color temperature rendering index
luminescence characteristics
