OPTICAL PICK-UP FOR WRITING/READING INFORMATION AND OPTICAL WRITING/READING APPARATUS AND METHOD EMPLOYING THE SAME

摘要

PURPOSE: An optical pick-up for writing/reading information and an optical writing/reading apparatus and method employing the optical pick-up are provided to control optical powers of two light sources emitting lights having different wavelengths using one photo-detector used for a monitor. CONSTITUTION: An optical pick-up for writing/reading information includes the first and second light sources(10,15) that emit light beams having different wavelengths and are selectively driven according to the kind of a recording medium(60), the first beam path converter(20) that reflects the beam emitted from the first light source, transmits the beam emitted from the second light source and sends a beam reflected from the recording medium in one direction, and an object lens(40) for focusing the beam inputted from the first beam path converter to form a beam spot on the recording medium. The optical pick-up further includes the second beam path converter(30) for converting the traveling path of the beam inputted from the first beam path converter, a main photo-detector(70) for receiving the beam that passes through the first and second beam path converters to detect an information signal, and a monitor photo-detector(80) for monitoring optical powers of the first and second light sources. A monitoring signal of the monitor photo-detector is used for controlling the optical powers of the first and second light sources.