Dispositif de tête optique

Optical head device

Vorrichtung mit optischem Kopf

Abstract

A light beam emitted from a semiconductor laser (114) element is collimated by a collimating lens (102), and is applied to an optical disk (105) through a polarizing holographic beam splitter (181), a λ/4 plate (115) and an objective lens (103), a light beam reflected by the optical disk is applied to the polarizing holographic beam splitter and is diffracted. Diffracted light beams of +1st order and -1st order are applied to two photodetectors (191, 192), and a focus error signal is obtained on the basis of the diffracted light beam of +1st order and a tracking error signal is obtained on the basis of the diffracted light beam of -1st order.

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Patent Citations (1)

    Publication numberPublication dateAssigneeTitle
    JP-S63314502-ADecember 22, 1988Nec CorpDouble refractive diffraction grating type polarizing plate

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Cited By (5)

    Publication numberPublication dateAssigneeTitle
    EP-0814467-A2December 29, 1997Nec CorporationOptischer Kopf
    EP-0814467-A3June 16, 1999Nec CorporationTête optique
    US-5737296-AApril 07, 1998Matsushita Electric Industrial Co., Ltd.Focus and tracking error detection by using plus and minus first order diffracted light
    US-6014359-AJanuary 11, 2000Nec CorporationOptical head with a polarizing diffractive element
    WO-2004109666-A1December 16, 2004Koninklijke Philips Electronics N.V.Appareil de lecture/ecriture pour support de stockage optique