Optical head device

Abstract

Abstract PURPOSE:To satisfactorily detect intra-plane deviation between an irradiating light spot and a track even if an optical disk is inclined, by diffracting and separating the luminous flux from a light source into plural luminous fluxes and detecting intra-plane deviation between the information track and the 0th- order diffracted light spot by a diffracted light other than the 0th-order diffracted light. CONSTITUTION:A photodetector 10 is placed in such position in the direction of the optical axis that the reflected light of a center beam, namely, a 0th-order diffracted light 9a forms a minimum deranged circle. In the photodetector 10, three beams are detected in 6 positions, and the 0th-order light out of three beams is received by 4 divided detecting parts 10a-10d, and the +1st-order light and the -1st-order light on both sides are received by detecting parts 10e and 10f independent of each other. Outputs of detectors 10e and 10f on both sides are differentially operated by a subtractor 13 or the like, and the output is outputted as a tracking error signal, thereby detecting intra-plane deviation between a center spot 9a and a track 8.

Inventors

• 👤 Hidekazu Tode
• 👤 都出　英一
• 👤 Shinsuke Shikama
• 👤 信介 鹿間
• 👤 Mitsushige Kondo
• 👤 近藤　光重

Bibliographic Details