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:
Mar. 06, 1984
Filed:
Aug. 12, 1981
Applicant:
Inventors:
Henry F Berdat, Manchester, CT (US);
Kerry D Baines, Vernon, CT (US);
Assignee:
The Gerber Scientific Instrument Company, South Windsor, CT (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
354-4 ; 3541951 ; 346108 ; 367 96 ;
Abstract
A photoplotter includes an autofocus control for maintaining a precise focal distance between a photohead in the plotter and the film surface which is exposed by the head. The autofocus control employs a dual frequency ultrasonic ranging apparatus which permits coarse focus control at one frequency and fine focus control at a second, higher frequency.