| 摘要 |
PURPOSE:To enable accurate infrared ray quantity to be detected and achieve miniaturization and simplification by applying the bias voltage corresponding to the accumulated charge quantity other than quantity of received light in the current detecting circuit in which an infrared ray detecting element and a switch element are series-connected. CONSTITUTION:A bias voltage VT is applied to the inside of the current detecting circuit in which an infrared ray detecting element S and switch element SW are series-connected. VT is expressed by VT = QY/C0. Here, QT, C0 are the charge quantity and capacity value of the element S, respectively. Then, the increment DELTAQ by the energy of received light flows through a resistance R0. This current is let to be DELTAi. Hence, the composite value of the voltage drop component of the resistance R0 and the bias voltage VT is voltage-amplified and therefore the voltage in (a) in the figure becomes VT + DELTAiR0. If the input voltage of an amplifier 1 is e1, the output voltage V0 in (b) in the figure is V0 = R2/R1 (e1 - VT) = R2/R1 (DELTAiR0) = R2.R0/R1 X DELTAi, thus only the charge increment corresponding to the energy of received light is obtainable. Here, R1, R2 are resistances. |
