Distance measuring device for camera using integration of reflected light

摘要

A distance measuring device for a camera projects a pulsed light beam toward a subject and converts the reflected light from the subject to a voltage which is integrated by an integrating circuit. The output of the integrating circuit is compared with a first reference voltage until the level thereof exceeds the first reference voltage, and then the output of the integrated circuit is compared with a second reference voltage until the level thereof reaches the second reference voltage. The distance to the subject is calculated depending on the number of times the integration operation is performed.