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Visual function test apparatus
 
   
Document Number
US Patent 6652102
Issued Date
November 25, 2003
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Abstract
A visual function test apparatus for testing a visual function by presenting an optotype to an examinee's eye is disclosed. This apparatus includes a first half mirror disposed on a projection optical axis of light of the optotype; an illumination light source having a projection optical axis which is made substantially coaxial with the projection optical axis of the optotype light by the first half mirror; a concave mirror which reflects an illumination light from the illumination light source and the optotype light; a second half mirror disposed between the first half mirror and the concave mirror, the second half mirror reflecting the optotype light and the illumination light both reflected by the concave mirror toward the examinee's eye; and a control section which changes a ratio between a light quantity of the optotype light and a light quantity of the illumination light in accordance with a predetermined contrast ratio.
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Number of Claims:
15
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Owner
Nidek Co., Ltd (Gamagori,JP)
Published
November 25, 2003
Application Number
09/977,299
Filed
October 16, 2001
US Classification
351/243  
Int'l Classification
A61B   3/032   (20060101)   A61B   3/06   (20060101)   A61B   3/02   (20060101)  
Examiner
Assistant Examiner
Attorney/Law Firm
Priority Data
Oct 20, 2000 [JP] 2000-327010
USPTO Field of Search
351/222   351/239   351/240   351/241   351/242   351/243   351/244   351/245   351/246  
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