Title:
AUTOMATIC FOCUSER
Document Type and Number:
Japanese Patent JPS59101832
Kind Code:
A
Abstract:
PURPOSE:To enable focussing with high accuracy by directly observing the inside of a field of view of an objective without being brought into contact with a body to be observed an focussing the objective. CONSTITUTION:A pattern sensor 5 is arranged to the joined focal surface O' surface of the pattern of the O surface of a photo-mask 1 by the objective 4, and pattern sensors 20, 19 are arranged to the joined focal surface P', Q' surfaces of P, Q surfaces upper and lower than the O surface only by (l). When the photo-mask 1 approaches to a P surface from the O surface, difference is generated in the pattern edge signals of the pattern sensors 19, 20, and difference between the differential signals of the pattern edge signals is shown in a graph (c). The photo-mask 1 emitting an output shown in a graph (e) is moved, and the expanded projected image of the pattern of the photo-mask 1 is focussed with the pattern sensor 5.
Inventors:
NOMOTO MINEO
AIUCHI SUSUMU
AIUCHI SUSUMU
Application Number:
JP21140682A
Publication Date:
June 12, 1984
Filing Date:
December 03, 1982
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G01N21/17; H01L21/027; H01L21/30; H01L21/66; (IPC1-7): G01N21/00; H01L21/66
Attorney, Agent or Firm:
Toshiyuki Usuda