Laser beam emitting device and an optical pickup provided with the laser beam emitting device

摘要

A laser beam emitting device has a laser beam source for emitting a laser beam having a prescribed effective optical path region; and a light-receiving element positioned outside the effective optical path region of the laser beam emitted by the laser beam source and having a plurality of light-receiving regions for detecting intensity of the emitted laser beam. In this device, the output of the laser beam source is adjusted in response to the intensity of the emitted laser beam detected by at least one of the plurality of the light-receiving regions of the light-receiving element. The light-receiving element includes a first light-receiving region located at a position near the optical axis and a second light-receiving region located at a position farther from the optical axis than the position of the first light-receiving region. The arrangement of the first and second light-receiving regions can provide at least three sensitivity levels by selecting one of electrical current values outputted from the plurality of light-receiving regions or any combination of these electrical current values. The laser beam emitting device is provided in an optical pickup for use in an optical disc drive such as CD-R drive.