Light sensor with optical hollow element - has brightness of inner surfaces adjustable to match external light around sensor

摘要

The hollow element has reflecting walls and windows whose aperture can be stopped. Daylight enters through the window, and light reflected from the walls is measured by photocells, phototransistors, photoresistors etc. Measurement results and their changes are used for digital or analogue switching of fixed or movable outdoor lighting. Inner walls of the hollow element can have a fixed or an adjustable brightness controlled by slides, blinds etc., so that the reflected light received by the measurement devices can be adjusted to the external light around the sensor.