JPS5914130U

JPS5914130U - Media position detection device in focus servo

Info

Publication number: JPS5914130U
Application number: JP6559183U
Authority: JP
Inventors: 本庄　義彦; 鶴窪　隆
Original assignee: 日本ビクター株式会社
Priority date: 1983-04-30
Filing date: 1983-04-30
Publication date: 1984-01-28

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

第１図は本出願人が先に提案した媒体位置検出装置の一
例の概略系統平面図、第２図は第１図の■−■線方向か
ら見た一部縦断立面図、第３図は第１図の■−■線方向
から見た一部縦断立面図、第４図は、本考案装置の一実
施例の構成図である。１・・・反射鏡、１′・・・トラッキングサーボ用ガル
バノミラ−１２・・・対物レンズ、４，６．２３・・・
反射鏡、１４．２４・・・入Ｉ２板、１５．１８・・・
半透明鏡、１９・・・グラフ・トムソン・プリズム。゛＼FIG. 1 is a schematic system plan view of an example of a medium position detection device previously proposed by the applicant, FIG. 2 is a partial vertical sectional elevational view taken from the direction of line ■-■ in FIG. 1, and FIG. 1 is a partially longitudinal sectional elevational view taken from the direction of line 1--2 in FIG. 1, and FIG. 4 is a configuration diagram of an embodiment of the device of the present invention. 1... Reflection mirror, 1'... Galvanometer mirror for tracking servo 12... Objective lens, 4, 6.23...
Reflector, 14.24...Input I2 board, 15.18...
Semi-transparent mirror, 19...Graff-Thomson prism.゛＼

Claims

[Scope of utility model registration request]

An objective lens that focuses a beam on a recording medium to record an information signal on a recording medium by changing the geometric shape of intermittent pits, or a light beam to reproduce an already recorded information signal from the recording medium. In a focus servo of a recording or reproducing device, which follows the surface vibration phase on a recording medium using a signal obtained from another light beam for detecting the medium position and displaces the recording medium so as to maintain a certain distance from the recording medium.
A recording or reproducing light beam and a medium position detection light beam from a different optical path are connected to a first light beam with different polarization planes.
and a second linearly polarized light, and a polarizing prism capable of separating the first and second linearly polarized light is arranged in the optical path of the recording or reproducing light beam between the rotatable tracking servo mirror and the objective lens. the recording or reproducing light beam and the medium position detecting light beam are provided simultaneously on the recording medium through the objective lens, and the recording or reproducing light beam that has passed through the objective lens and the medium position detection; The second linearly polarized light beam reflected from the recording medium is separated by the polarizing prism, and the second linearly polarized medium position detection light beam is received by a differentially coupled photodetector. A medium position detecting device in a focus servo, which is characterized in that it is configured to do so.