An exposure apparatus includes a pulsed light source for repeatedly emitting a pulsed light; a photoelectric converting device for receiving at least a portion of the pulsed light from the pulsed light source; and a control device for controlling the emission of the pulsed light source, on the basis...http://www.google.com.au/patents/US5053614?utm_source=gb-gplus-sharePatent US5053614 - Exposure control method and apparatus compensating for detection of offset from a measured value
