| 摘要 |
PURPOSE:To completely compensate the measurement error caused by light chopper plate, by using light quantum type infrared ray detection element, establishing auxiliary radiation source which has transparent window in front of the light chopper, and limiting the auxiliary radiation temperature in correlation with that of the radiation heat. CONSTITUTION:Infrared detection element D is of light quantum type, and the window is provided within case 1 wherein chop of the photoelectric element is built in together with Peltier effect element for cooling purpose. Case 1 is fixed on the heat radiation plate 3, and the heat is discharged outside. Light chopper CH has chopper plate 4 of semicircular shape which interrupt the incoming light for 1/2 period of the time of the rotation cycle. Between the light chopper and focusing optical lens 5, an auxiliary radiation ray source HS which has light piercing hole and heater 7 in its center is provided. Temperature detection element 10 generates electric voltage which corresponds to the temperature of the heat radiation plate 3, and the control circuit 9 controls the electric power of the heater 7 in accordance with tht voltage outputted by the temperature detection element 10. Because of the abovementioned constitution, temperature of the chopper plate 4 changes itself with both the temperatures of the heat radiation plate 3 and the auxiliary radiation ray source HS, enabling the compensation for measurng error. |
