White-light emission from near UV InGaN-GaN LED chip precoated with blue/green/red phosphors

Author

Sheu, J.K. ; Chang, S.J. ; Kuo, C.H. ; Su, Y.K. ; Wu, L.W. ; Lin, Y.C. ; Lai, W.C. ; Tsai, J.M. ; Chi, G.C. ; Wu, R.K.

Author_Institution

Opt. Sci. Center, Nat. Central Univ., Taiwan, Taiwan

Volume

15

Issue

1

fYear

2003

Firstpage

18

Lastpage

20

Abstract

Phosphor-converted light-emitting diodes (LEDs) were fabricated by precoating blue/green/red phosphors onto near ultraviolate (n-UV) LED chips prior to package into LED lamps. With a 20-mA injection current, it was found that the color temperature T/sub c/ was around 5900 K and the color-rendering index R/sub a/ was around 75 for the "n-UV+blue/green/red" white LED lamps. It was also found that no changes in color temperature T/sub c/ and color-rendering index R/sub a/ could be observed when we increased the injection from 20 to 60 mA. These results indicate that such "n-UV+blue/green/red" white LEDs are much more optically stable than the conventional "blue+yellow" LEDs.

Keywords

III-V semiconductors; gallium compounds; indium compounds; light emitting diodes; phosphors; 20 mA; 20 to 60 mA; 5900 K; InGaN-GaN; LED chips; blue/green/red phosphors; color temperature; color-rendering index; injection current; near UV InGaN-GaN LED chip; package; phosphor-converted LED; phosphor-converted light-emitting diodes; precoating; white-light emission; Epitaxial growth; Gallium nitride; LED lamps; Light emitting diodes; Optical pumping; Packaging; Phosphors; Quantum well devices; Stimulated emission; Temperature;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2002.805852

Filename

1159048