| 摘要 |
PURPOSE:To obtain a rapid optical reading memory by forming a bistable circuit by a hetero junction bipolar transistor (TR) adopting a direct transition type semiconductor as its base and driving said circuit by a constant current TR. CONSTITUTION:The hetero junction bipolar TR adopting GaAs as its base emits light in a saturated area and does not emit light in an activated area or an interrupted area. When a memory cell constituted of said element is not selected, an optical signal 29 is not inputted to the base of a constant current TR 15, a base bias current is inputted from a wiring 27 and a constant current is supplied to the bistable circuit. The current value is set up to a value which does not satisfy an element 13 on the ON side. When the memory is selected, an optical signal 29 is inputted to the element 15, the operating point of the element 13 is transferred to a saturated area to emit light and the operating point of the element 11 is kept at an interrupted area to interrupt light emission. Namely, the reading of the contents of the memory can be executed only by the optical signal, so that reading delay time due to the capacity of the wiring can be removed and a high response memory can be obtained.
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