| 摘要 |
PURPOSE:To facilitate the accurate measurement of illuminance, by providing a photodetector for measuring the quantity of incident light and a sensor for measuring spectral distribution of the incident light. CONSTITUTION:Outputs to lights incident to two photodiodes 3 and 4 differing in spectral sensitivity enter logarithmic compressing circuits 5 and 6, and subtracting circuit 7, and signal Vc that corresponds to the spectral distribution of the incident lights is outputted. Signal Vc is inputted to ROM9 via AD converter 8. A corrected signal from ROM9 is inputted to multiplying DAC10 and multiplied by input signal Vx to the quantity of incident light inputted via photodetector 11 and amplifier 12 to output signal Vo proportional to the illuminance of the photodetection. Therefore, the accurate illuminance can easily be measured. |
