公开(公告)号：JPH0827178B2

公开(公告)日：1996-03-21

申请号：JP29700492

申请日：1992-11-06

Applicant: IBM JAPAN

Inventor： MORITA TETSUHARU ,  KUNO TEIJI ,  FUKUZAWA TADASHI ,  ISOKI KOICHI ,  NODA HIROSHI

IPC: G01B9/02 ,  G01B11/14 ,  G01D1/02 ,  G11B21/21

公开(公告)号：JPH0887724A

公开(公告)日：1996-04-02

申请号：JP22132394

申请日：1994-09-16

Applicant: IBM JAPAN

Inventor： FUKUZAWA TADASHI ,  KUNO TEIJI ,  WATABE HIROSHI ,  TAKAHASHI YASUYUKI ,  OZAWA KOJI

IPC: G11B5/455 ,  G01B11/14 ,  G02B27/00 ,  G02B27/28 ,  G11B5/60 ,  G11B33/10

Abstract: PURPOSE: To maintain a high measuring accuracy by making a measuring error due to an optical elastic phenomenon minimum by providing the polarization eliminator through which light reaching reflection member and light reflected from reflection parts pass in between optical lens member and the reflection member. CONSTITUTION: When light in a linear polarization state by passing through a polarizer 503 passes through a 1/4λ plate 570, it becomes a circular polarization state and receives multiple interfering actions reflected respectively from surfaces of a glass disk 23 and a head 21. These reflected lights are restored to linear polarization states by passing through again the 1/4λ plate 570. The direction of the linear polarization at this time is a direction rotated by 90 deg. from an original direction, at first, the direction of the linear polarization perpendicular to this paper plane becomes a linear polarized light having the polarization direction horizontal to the paper by passing through the 1/4λplate twice. Then, lights whose polarization directions are rotated by 90 deg. in such a way pass through again ojective lens system 507 to reach finally an optical detecting part 515 via an analyzer 513. Moreover, the polarizer 501 and the analyzer 513 are arranged in a form in which transmission polarization axes of them are orthogonal to each other.

公开(公告)号：JPH06147841A

公开(公告)日：1994-05-27

申请号：JP29700492

申请日：1992-11-06

Applicant: IBM JAPAN

Inventor： MORITA TETSUHARU ,  KUNO TEIJI ,  FUKUZAWA TADASHI ,  ISOGI KOUICHI ,  NODA HIROSHI

IPC: G01B9/02 ,  G01B11/14 ,  G01D1/02 ,  G11B21/21

Abstract: PURPOSE:To provide a floating amount measuring apparatus for head which exhibits high sensitivity through simple structure. CONSTITUTION:Light projected from a white light source 25 is introduced into a gap between a disc 23 and a head 21 where multiple reflection takes place. Light reflected on an opaque body, out of the disc 23 and the head 21, is polarized into at least three wavelength regions and introduced to different optical detecting means 35, 36, 37. An estimating unit 38 estimates floating amount of head from an output of the optical detecting means according to the method of least squares based on a function between disc head gap lengths predetermined for respective wavelength regions and the intensity of reflected light detected through the optical detecting means. Calculation is carried out in real time according to table lookup system or follow-up control system.