Patent ID: 7751741

Claim:
An optical sensor for detecting image information, comprising: a light-emitting element configured to direct light to an image; a light-receiving element configured to receive light reflected from the image; a normal detection optical path configured to allow the light emitted by the light-emitting element and the light reflected from the image to follow a normal detection optical path during normal operation; a calibration reflecting plate disposed inside the optical sensor, configured to reflect light from the light-emitting element when sensitivity is calibrated; a calibration optical path from the light-emitting element to the light-receiving element that is different from the normal optical path utilized when the emitted light is reflected by the calibration reflecting plate; and a first optical function element disposed in the calibration optical path, configured to be switchable between a light permeating state, in which the light passes therethrough, and a light intercepting state, in which the light is blocked, when voltage is applied.