Development of junction temperature measurement system for blue LED in operation using pulsed-laser Raman scattering

A novel method by using a pulsed-laser Raman scattering technique was employed to estimate junction temperatures of a phosphor-less blue-LED module. Observation of GaN-E_2^H Raman spectra was done successfully and temperature dependent Raman spectra of GaN were detected. This technique was applied to simultaneous estimation of the junction temperatures of the several chips in the phosphor-less blue LED module in operation. It is concluded that this technique would be a useful method for remoteness and simultaneous multipoint measurement of the junction temperature of a LED module in which several chips are integrated.