| 摘要 |
PURPOSE:To eliminate the thermal influence of a measuring element, etc. owing to constant irradiation and to enable stable irradiation of a ray by constant lighting by providing a shutter mechanism in the optical path of the photometric ray and irradiating the photometric ray only in the stage of measurement. CONSTITUTION:An optical means 20 for photometry is constituted of a light source 21, a condenser lens 23, a cylindrical slit 25, etc. and a shutter vane 34 which can be advanced into and retreated from the optical path by a rotary solenoid 35 is provided in the optical path. The operator presses a prescribed knob to bring tightly a measuring element 12 into contact with the head of an irradiating cylinder 19 of an optical system in the stage of measurement, then the solenoid 35 is actuated cooperatively with the knob and the vane 34 is retreated from the optical path, by which the measuring ray is irradiated to the measuring element 12. The light reflected therefrom is detected with a photodetector 29 and a prescribed measured value is recorded. The irradiation is thus accomplished only in the stage of measurement, by which the thermal influence of the measuring element, etc. is eliminated and the stable irradiation is made possible as the light source 21 is constantly lighted. |
