| 摘要 |
PROBLEM TO BE SOLVED: To provide a received light intensity measuring device capable of obtaining a digital value that is according to the light intensity received with a high resolution, while permitting variations in the accuracy of a comparator. SOLUTION: There are provided a photodiode (PD) which stores electric charge whose amount is according to the light intensity received, a floating diffusion (FD) which outputs a signal voltage V<SB>CL</SB>according to the amount of retained charge, a pixel circuit 1 which comprises a transfer switch, which is connected to the PD and FD and controls the movement of charge stored in the PD into the FD, a DAC 11 which produces a control voltage V<SB>TRAN</SB>, which changes in the shape of lamp wave to impress the same on the gate of the transfer switch and a sequence AD conversion circuit 13, which obtains the digital value, by quantizing the time length, from a predetermined time point to a time point whereat a specified fluctuations are generated in the time rate of change of the signal voltage V<SB>CL</SB>, in accompaniment with the impression of the control voltage V<SB>TRAN</SB>. COPYRIGHT: (C)2009,JPO&INPIT
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