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:
Oct. 12, 1999
Filed:
Jun. 20, 1997
Applicant:
Inventor:
David W Samuelson, London, GB;
Assignee:
DSAM Limited, London, GB;
Primary Examiner:
Int. Cl.
CPC ...
G01B / ;
U.S. Cl.
CPC ...
356124 ;
Abstract
A testing apparatus for an optical system comprises a plurality of markers disposed along an axis to be aligned with the optical axis of the optical system, the markers being axially spaced from one another and angularly displaced relative to one another so as to effectively define a helix about the axis. When viewed from one end of the apparatus the markers provide focusing and depth of field information, and some aberrational information about the optical system. Preferably the markers are spaced so as to correspond to the depth of field of the lens aperture stop values of a camera, allowing the aperture settings of the camera to be tested.