| 摘要 |
PURPOSE:To maintain high accuracy in detecting infrared rays, by providing a temperature detector, which outputs a DC signal for biasing a vibrator in DC based on the detected temperature of the vibrator, providing a specified voltage applying means, which applies a specified voltage to the vibrator at a desired time, and ensuring the change in the amount of incident infrared rays to an infrared ray detecting body at a specified difference. CONSTITUTION:A numeral 58 is an oscillator comprising an astable multivibrator. A numeral 62 indicates a control part comprising a micro-computer and the like, which outputs a temperature display signal D based on a digital signal from a conveter 61 and pulses from said oscillator 58. A very large specified voltage -60V from a constant voltage applying circuit 59 is applied to a first vibrating elecrode at every 5 seconds. Then, a bimorph 30 is deflected to the direction B very largely as shown by the hysteresis characteristic every time. When -60V is applied, the bimorph 30 is deflected to the direction A along a line H with good reproducibility based on a desired bias voltage. Therefore, the deflecting amount of the bimorph 30 is sequentially corrected at every 5 seconds even though the bimorph is under the deflected state due to the decreasing trend of the bias voltage. That is, a second infrared ray transmitting part is corrected so that a first infrared ray transmitting part is completly overlapped with a first infrared ray stopping part. The decrease in the amount of infrared rays that is inputted to an infrared ray detecting body 2 is suppressed. |
