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:
Nov. 07, 1989
Filed:
Jul. 18, 1988
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Abstract
Disclosed is a novel optical system for illuminating an object which provides an increased irradiance in the peripheral area of the object. The optical system includes a light source, an entrance pupil for receiving light from the light source, an exit pupil for passing the light received to the object, and an optical axis which extends through the optical system to the light source and the object, respectively, wherein the relationship among the incident height h to the entrance pupil, an illumination height H on the object, and a changing rate (dh/dH) of the incident height and the illumination height is defined by a function, f(H)=(h/H)(dh/dH). The optical system is designed so as to satisfy the following formula in the peripheral area of the object: f(0)<f(H). The function f(0) is represented by f(0)=[fa'/(a'-f)b'}].sup.2, where a' is a distance between the light source and the primary principal point of the optical system, and b' is a distance between the real image of the light source and the object.