Title:
MEASURING METHOD AND MEASURING DEVICE FOR SMALL DISPLACEMENT QUANTITY
Document Type and Number:
Japanese Patent JPH05141935
Kind Code:
A
Abstract:
PURPOSE:To provide the method and device capable of correctly measuring a small displacement quantity in the optical axis direction on a test surface. CONSTITUTION:The interferable light from a light source 1 is radiated to a test surface 7a and a reference surface 6a to form interference fringes 11 in an interference optical system, and the interference fringes 11 are image-formed on an area sensor 10 by a focusing optical system 9. When the distance between the reference surface 7a and the test surface 6a is continuously changed, the interference fringes 11 are moved in the length direction in response to the change. The area sensor 10 observes the moving state at two or more observation points P1, P2 having the phase difference of npi/2 between the interference fringes 11, where (n) is a natural number. When the inversion of contrast, the number of times, and the timing of the inversion at these observation points P1, P2 are detected, a small displacement quantity can be calculated.
Inventors:
SUZUKI SEIZO
SUHARA HIROYUKI
SUHARA HIROYUKI
Application Number:
JP5068592A
Publication Date:
June 08, 1993
Filing Date:
March 09, 1992
Export Citation:
Assignee:
RICOH KK
International Classes:
G01B11/24; G01B11/245; (IPC1-7): G01B11/24
Attorney, Agent or Firm:
Hideo Takino (2 outside)