| 摘要 |
PURPOSE:To attain coexistence of monochroic reading and color reading and also high speed reading by outputting signals from an output line of three photodetectors in a form of parallel signals depending on chrominance signals. CONSTITUTION:An input selection signal converted into a multi-threshold logical signal is received at an input terminal 14, a current from a current source 16 controlled by a block selection input signal 15 flows to a desired branch, and three kinds of photo transistor (TR) arrays 32a-36b, 37a-40b, 41a-44b are accessed though switching TRs 28a, 28b-31a, 31b of 3-output subject to switching operation while sensing the current. When a block selection input terminal goes to ''H'' and bit selection input signals A, B, C go respectively to ''L'', the current from the current source flows only to a resistor 24a, a base potential is decreased only to the TR28a and turned on, a charging current flows to the photo TRs 32a, 37a, 41a and its read signal is outputted in a form of parallel output by each chrominance signal from each output line. No current flows to the other photo TRs, which are brought into the integration period (non access period).
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