SEMICONDUCTOR LIGHT EMITTING DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent the sensitivity of a light receiving element from lowering even if the wavelength thereof fluctuates due to temperature rise. SOLUTION: The semiconductor light emitting device comprises a semiconductor light emitting element 5 having standard wavelength set atλ0 and a wavelength at the upper limit temperature in operation guarantee range varying toλ1, and an element 6 for receiving light from the light emitting element 5 through a surface coating 7. Difference of transmittance between the light of wavelengthλ0 and the light of wavelengthλ1 transmitting through the coating 7 is determined by varying the thickness of the coating and the thickness of the coating is set within such a range as the difference of transmittance has a positive value.