Illuminance distribution measuring system

摘要

Illuminance distribution measuring method and apparatus, in which the quantity of light on an area irradiated by a light beam emitted from a light source is detected by a combination of first and second detectors. The first detector is movable along the area to be irradiated and detects the quantity of irradiating light incident on the area to be irradiated while moving along the area irradiated. The second detector is fixedly secured at a predetermined position relative to the light source and the area to be irradiated and receives the light beam emitted from the light source to irradiate the area to be irradiated. On the basis of the outputs from the first and second detectors, the illuminance distribution on the area irradiated is accurately measured irrespective of any intensity changes of the light beam emitted from the light source.