| 摘要 |
The optical system includes a collection lens (10) with an optical axis (11), and a light-sensitive detector plate (12). The detector plate is located in the focal plane of the system, and emits a current (13) proportional to incoming radiation which is amplified in an amplifier (14). In front of the detector plate is a movable sun screen (15) in the form of a long horizontal strip or rod extending over the whole detector plate. On its side turned away from the detector plate and towards the light entry aperture, the sun screen has two light-sensitive surfaces. The uppermost surface is connected to the positive input of a differential amplifier, whilst the lower surface is connected to the amplifier negative input. Output signals from the light-sensitive surface of the sun screen are fed to a drive unit which moves the screen over the detector plate. The drive unit and the light-sensitive surface form a servo-circuit which when radiation from the sun comes into the detector causes the screen to be automatically driven to the position where the picture of the sun is located on the detector plate, thus preventing solar radiations reaching the plate. (Provisional basic advised week 89/02) |
