Title:
MEASURING APPARATUS FOR WARPED SHAPE OF DISC
Document Type and Number:
Japanese Patent JPH01267403
Kind Code:
A
Abstract:
PURPOSE:To measure a three-dimensional shape of warping, by correcting distances to points on a disc from an outside specified point from an angle of warping at a point where the distance involved is measured. CONSTITUTION:A radial distance (r) from the center of a rotating axis at a measuring point A on an optical disc 1 is calculated based on a signal to be outputted from a motor 3 according to the rotation of a pinion 5 moving along a rack gear 6. An angle theta from radial reference line is calculated based on a signal to be outputted from a motor 2 for turning the optical disc 1. Moreover, a distance x to the measuring point A from a probe 41 is measured with a measuring section (not illustrated). A position sensor 45 detects an angle of warping of the optical disc 1 at the measuring point A from a displacement of reflected light from the optical disc 1 between an incoming position and a reference incoming position. Then, the distance (x) is corrected by a correction means (not illustrated) using the angle of warping, thereby achieving a higher measuring accuracy in a three-dimensional shape of a disc.
Inventors:
MIYAI YOSHIO
Application Number:
JP9754988A
Publication Date:
October 25, 1989
Filing Date:
April 19, 1988
Export Citation:
Assignee:
SANYO ELECTRIC CO
International Classes:
G01B11/24; G01B21/20; G11B7/26; (IPC1-7): G01B11/24; G01B21/20; G11B7/26
Attorney, Agent or Firm:
Nobuo Kono
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