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:
Jul. 28, 2009
Filed:
Mar. 31, 2004
Toshifumi Mihashi, Tokyo, JP;
Toshifumi Mihashi, Tokyo, JP;
Kabushiki Kaisha Topcon, Itabashi-ku, JP;
Abstract
A refraction measuring instrument for measuring the refraction of an eye to be examined while the subject is viewing an external object in a more natural posture. A measuring light beam from a light sourceis reflected from a mirror, shaped into a beam with a ring cross section, directed to a free curved surface prismalong an optical axis O, reflected from a surfaceand a beam splitting surface, guided to an eye E along an optical axis Otogether with the visible light from outside the instrument, and form a ring pattern on the fundus F. The measurement beam reflected from the fundus F is received by a CCDthrough the free curved surface prismand a prism, and a ring pattern is imaged. A calculation control deviceanalyzes the imaged ring pattern and calculates the sphericity, the degree of astigmatism, and the astigmatic axis angle. For measurement, the subject A wears the refraction measuring instrumenton the head H through a wearing section