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:
Dec. 30, 1980
Filed:
Sep. 05, 1978
Sidney Weiser, Silver Spring, MD (US);
Exotech, Incorporated, Gaithersburg, MD (US);
Abstract
The invention is an apparatus for determining the quality of optical equipment through measurement of the modulation transfer function of the equipment. The apparatus includes an elongated, opaque sheet member or reticle, uniformly curved about an axis substantially perpendicular to the longitudinal centerline thereof, which has a data pattern comprising at least one bar pattern of discrete spatial frequency positioned longitudinally thereon. Each of the data patterns has optical transmission characteristics that vary periodically along its length according to a predetermined spatial frequency distribution. A rotatable mirror with its axis of rotation coincident with the center of curvature of the reticle is mounted so that it reflects an incident image onto the stationary reticle. An illuminated image producing source projects a slit image through optical equipment whose quality is to be determined to produce a spread function response of the optical equipment and the response is projected onto the rotatable mirror. The mirror is rotated to cause the spread function response to be reflected therefrom and sweep the data pattern so that the light transmitted through the data pattern is modulated by the interaction of the data pattern with the spread function response. The intensity of the transmitted, modulated light from the slit image is converted into an electrical data signal and the amplitude of the fundamental frequency components of the electrical data signal is determined. These measurements determine the modulation transfer function of the optical equipment under test.