公开(公告)号：JPH03139651A

公开(公告)日：1991-06-13

申请号：JP26824290

申请日：1990-10-04

Applicant: HOLTRONIC TECHNOLOGIES LTD

Inventor： RENE DANDORIKEE ,  MASUU AMIDEI ,  JIYON EDOWAADO BURUUKU

IPC: G01B9/021 ,  G01N21/88 ,  G01N21/956 ,  G02B7/28 ,  G03F7/20 ,  G03F9/00 ,  G03H1/00 ,  H01L21/027

Abstract: PURPOSE: To optically detect a relative position between hologram and a recording medium by making a light beam advance straight so as to be made incident practically at the right angle on a prism and the surface of the hologram recorded beforehand on a first recording medium. CONSTITUTION: The light beam led to the prism 22 and made incident practically at the right angle on the surface of a first substrate 16 provided with the hologram recorded beforehand on the first recording medium is partially reflected on the boundary surface of the hologram and air and a part passed through reaches a second recording medium and a second substrate 30 and is reflected. The two reflected beams interfere with each other and return along an incident path. Then, the interfering beams are resolved by an interference technique or a diffraction technique so as to obtain signals corresponding to a distance between reflection surfaces. Thus, the distance between a hologram surface and the recording medium is optically detected.