| 摘要 |
PURPOSE:To measure laser beam power with high accuracy from the output signal of a light receiver to which no filter is applied and that of a light receiver to which a filter is applied using a specific formula without using an auxiliary wavelength measuring means. CONSTITUTION:The light emitted from a light source 1 to be measured passes through an aperture 2 and a glass filter 4 to impinge against a silicon photodiode 3. The output signal of the photodiode 3 is taken in a microcomputer 9 through a current/voltage converter 7 and an A/D converter 8. The microcomputer 9 controls a filter change-over device 5 and the converter 8 and, from the output Sa of the light receiver (photodiode 3), of which the absolute spectral sensitivity Ra(lambda) is shown by Ra(lambda)=alambda+b to which a filter 4 is not applied and the output Sb of the light receiver, of which the spectral transmissivity tau(lambda) is shown by tau(lambda)=(clambda+d)/(alambda+b), to which the filter 4 is applied, the total quantity of the emitting power of incident light can be calculated according to formula (wherein a-d are coefficient).
|
