Patent ID: 6509921
Filing Date: 2003-01-21
Classification: G06K,H04N

Abstract:
A light beam scanning apparatus comprising:a light emitting device configured to output a light beam; a mirror configured to reflect a light beam toward a scanned face so that said light beam output from said light emitting device scans said scanned face in a horizontal scan direction; a plurality of sensors arranged on said scanned face or a position equivalent thereto, which detect a light beam scanned by said mirror and output an electric signal wherein said plurality of sensors comprises a plurality of first patterns outputs of which continuously increase and a plurality of second patterns outputs of which continuously decrease, in response to a change in a scanning position of the light beam in a direction orthogonal to the horizontal scan direction, and said plurality of first patterns and said plurality of second patterns are arranged alternately in the horizontal scan direction; a processing circuit configured to output a value obtained by integrating a difference between respective electric signals output from said plurality of sensors; and a control section configured to control a passage position of a light beam output from said light emitting device on said scanned face to a specified portion based on an output value from said processing circuit.