| Summary: | 碩士 === 國立成功大學 === 工程科學系碩博士班 === 96 === The purpose of this thesis is to study the characteristics of three high power R,G,B-LEDs (LUXEON-Rebel, LUXEON-Emitter, Osram-Golden Dragon) under the conditions of different substrate temperatures and driving currents. The driving current varies from 100 to 400mA and the substrate temperature from 25℃ to 70℃. The characteristics examined include the luminous flux and efficiency, main wavelength, peak wavelength, full width at half amplitude, chromaticity and induced voltage. The ambient temperature is control LED within the range of 24±1℃ for all the experiments.
Key observations are as follows. With increasing substrate temperatures, the luminous flux reduces, the main wavelength and peak wavelength linearly shift to long wavelengths, and full width at half amplitude widens. The x, y chromaticity makes a right-down shift for R,G-LEDs and left-up shift for B-LED. The luminous efficiency of R,G-LEDs reduces whereas that of B-LED increases slightly. With increasing driving current, the luminous flux increases. The main wavelength shifts to wavelengths while the peak wavelength of R-LED shifts to a long wavelength shift and those of B,G-LEDs to short wavelengths. The full width at half amplitude enlarges. The x, y chromaticity of R-LED exhibits a right-up shift, G-LED a left-down shift and G-LED a right shift. All of the luminous efficiencies of R,G,B-LEDs reduce.
The stability in terms of substrate temperature variation, the red Emitter LED and Osram’s G-LED are most stable. With increasing driving currents, the Emitter red and green LEDs are most stable.
|
|---|
