| 摘要 |
PURPOSE:To obtain an image sensor characterized by high speed, low noise and high resolution by encoding a selecting input signal for scanning so that the number of bits changed in each step of scanning is ''1''. CONSTITUTION:When block input terminals 14, 15 are ''1'' and ''0'' respectively and all complementary input signals A-C are ''0'', current from a current source flows only into a resistor 26a and does not flow into other load resistors. Consequently, only the base potential of a switching TR30a is dropped, the TR30a is turned on and photoelectric current flows only into a phototransistor 34a, so that the reading state is set. The current does no flow into other photo-TRs, which are set up to a charge accumulation mode. Then, the selection input signal for scanning is encoded so that the number of bits changed in each step of the scanning is ''1''. The inside of a decoder constituted of TRs 19-25 and the connection of a block current switch are scanned by the encoded signal.
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