The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 27, 1990
Filed:
Jan. 05, 1989
Applicant:
Inventor:
Paul E Cope, Fareham, GB;
Assignee:
The Marconi Company Limited, , GB;
Primary Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356400 ; 2502 / ; 356152 ; 356153 ;
Abstract
An optical alignment detector uses a Fresnel bi-prism (12) on the base of which an incoming beam of light is focussed. When the beam is in alignment, it strikes the base substantially normally and is brought to a focus adjacent a ridge (13) of the bi-prism (12). To cope with a second axis of alignment, a second bi-prism (14) having a ridge (15) is placed beneath the first, with the two ridges (13,15) arranged orthogonally so as to produce four possible pupil entrance images which can be received by four photodetectors (17,18,19,20).