TW279954B - Optical pick-up head - Google Patents

Abstract

An optical pick-up head, that is applicable to perform read-out of data signal, focus error signal and tracking error signal to record medium with recorded data, comprises of: one light source generator for emitting one beam; one diffraction device for diffracting the above light beam generate one main beam and two sub-beams; one focus device for focusing the above main, sub-beam to project to the above record medium, and focusing the reflected main, sub-beam from the above record medium to project the above diffraction device; one light sensing device for sensing diffracted main, sub-beam reflected from the above record medium, and outputting the above data signal, focus error signal and tracking error signal; It features that the above diffraction device has inner loop part located in the middle and outer loop part surrounding the above inner loop part, and the above outer loop part diffracts the outer portion of beam emitted from the above light source into the above sub-beam, and the above inner loop part diffracts the inner portion surrounded by outer portion of beam emitted from the above light source into the above main beam, in the same time the above inner part diffracts the above main, sub-beam reflected from the above record medium to the above light sensor.