Invention Grant
US07808878B2 Optical pickup apparatus and drive apparatus having the same 有权
光拾取装置及其驱动装置

Optical pickup apparatus and drive apparatus having the same
Abstract:
An optical pickup apparatus and a drive apparatus having the same are provided. Second light-receiving elements or third light-receiving elements for receiving ±first-order diffraction light beams from a polarization hologram are arranged outwardly of a circular region having the optical axis of a zero-order diffraction light beam on a light detector as its center, a radius of which is expressed by (2×t/n)×(f2/f1), where f1 denotes a focal length of an objective lens, f2 denotes a focal length of a coupling lens, t denotes a maximum value of a light transmitting layer thickness, n denotes a refractive index of a light transmitting layer.
Public/Granted literature
Information query
Patent Agency Ranking
0/0