发明申请
US20090324244A1 PHOTOMETRIC DEVICE 有权
光学设备

PHOTOMETRIC DEVICE
摘要:
A photometric device with a wide dynamic range. The photometric device includes a constant current generation circuit, a fixed clock signal generation circuit which generates a fixed clock signal having a fixed frequency, a photoelectric conversion element, a variable clock signal generation circuit and a digital signal generation circuit. The fixed clock signal generation circuit generates a fixed clock signal that oscillates at a fixed frequency, from constant current The variable clock signal generation circuit generates a variable clock signal that oscillates at a frequency proportional to the amount of photocurrent, from photocurrent generated in the photoelectric conversion element. The digital signal generation circuit sets a measurement period using the fixed clock signal, counts the number of pulses of the variable clock signal that oscillates for the measurement period, and outputs a digital signal including the count value as data.
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