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:
Sep. 19, 1989
Filed:
Jun. 17, 1988
Zenji Wakimoto, Kyoto, JP;
Takahisa Hayashi, Kyoto, JP;
Abstract
The image-forming magnification of a telecentric optical system, for use in an exposure apparatus such as a projecting apparatus, a laser plotter and the like is determined by the focal length ratio. An error in processing and arranging lenses necessitates adjustment of the image-forming magnification. According to the present invention, the magnification may be greatly varied. According to the present invention, a lens movable along the optical axis and having a positive focal length is placed at a position corresponding to the point at which the focal points of two lens groups coincide with each other. The image-forming magnification ratio can be varied by moving the lens while the distance between an object and an image is kept constant. Characteristic features of telecentric optical systems are maintained.