White illumination characteristics of ZnS-based phosphor materials excited by InGaN-based ultraviolet light-emitting diode

Kenji Murakami; Tsunemasa Taguchi; Masahiko Yoshino

doi:10.1117/12.389396

30 June 2000 White illumination characteristics of ZnS-based phosphor materials excited by InGaN-based ultraviolet light-emitting diode

Kenji Murakami, Tsunemasa Taguchi, Masahiko Yoshino

Author Affiliations +

Proceedings Volume 4079, Display Technologies III; (2000) https://doi.org/10.1117/12.389396
Event: Photonics Taiwan, 2000, Taipei, Taiwan

Abstract

White illumination characteristics of ZnS-based phosphor materials exited by an In_xGa_1-xN-based single quantum well-structure ultraviolet (UV) light-emitting diode (LED) have extensively been investigated. In order to evaluate white luminescence, two kinds of ZnS-based white phosphors have been employed. When an UV LED was operated at a current of 10 mA, chromaticity (x, y) color temperature (Tc) and general color rendering index (Ra) of the white luminescence are obtained to be (x,y) equals (0.29, 0.33), Tc equals 7700 K and Ra equals 70, respectively, for ZnS:Ag + (Zn,Cd)S:Cu,Al phosphors, whilst (x,y) equals (0.31, 0.34), Tc equals 6900 K and Ra equals 83, respectively, for white phosphor material including ZnS:Cu,Al, Sr and Y materials. The value of chromaticity slightly changed with increasing forward current of the UV light source. As a result, it is possible to obtain stable white luminescence spectrum. The dependence of the luminescence brightness on the thickness of phosphor shows a tendency to saturate for reflection brightness, but for transmission brightness its dependence has a peak due to light scattering effect. The reflection brightness was higher than the transmission brightness. It is revealed that the white luminescence light of stable chromaticity and high brightness using reflection light can be obtained.

Citation Download Citation

Kenji Murakami, Tsunemasa Taguchi, and Masahiko Yoshino "White illumination characteristics of ZnS-based phosphor materials excited by InGaN-based ultraviolet light-emitting diode", Proc. SPIE 4079, Display Technologies III, (30 June 2000); https://doi.org/10.1117/12.389396

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available