Patent ID: 6744031
Filing Date: 2004-06-01
Classification: G01J,G11B

Abstract:
A light intensity control apparatus, comprising:a light source driving device configured to drive a light source to generate a light having at least first and a second light intensity levels, said second level being higher than the first level; a first light intensity detection device configured to detect the second light intensity level and provide an output; a second light intensity detection device configured to detect an average of the intensity of the light and provide an output; a light intensity detection device selection device configured to select one of the first and second light intensity detection devices in accordance with a selection instruction; a reference providing device configured to provide first and second references of a second light intensity level and an average light intensity level; a reference selecting device configured to select one of the first and second references corresponding to a selection instruction; a comparison device configured to compare one of the outputs of the first and second light intensity detection devices with the corresponding selected one of the first and second references; and a driving current adjustment device configured to adjust a magnitude of a driving current configured to drive the light source in accordance with the comparison result.