| 摘要 |
PROBLEM TO BE SOLVED: To obtain the light measuring instrument which has a wide dynamic range and can accurately measure the quantity of incident luminous flux. SOLUTION: The light measuring instrument 10 is equipped with a timing pulse generator 14 which outputs a timing pulse signal with a period T, an HPD (optical detecting means) 16 which outputs a signal corresponding to the quantity of the incident luminous flux, a charge amplifier 20 which integrates the signal outputted from the HPD 16, a comparator 22 which outputs a saturation signal when the output of the charge amplifier 20 exceeds a reference voltage Vc, a counter 26 which counts how many times the saturation signal is outputted from the comparator 22, an A/D converter 28 which converts the output of the charge amplifier 20 from analog to digital, and an arithmetic part 30 which calculates the quantity of the incident luminous flux according to the output of the counter 26 and the output of the A/D converter 28. The charge amplifier 20 is rest with the timing pulse signal outputted by the timing pulse generator 14 and the mentioned saturation signal.
|
