Title:
【発明の名称】2次結像式ファインダ―光学系
Document Type and Number:
Japanese Patent JP2510138
Kind Code:
B2
Abstract:
PURPOSE:To observe a finder image of high optical performance by setting the lens constitution and refracting power of each lens group of the optical system which allows an erect real image reformed through a relay lens system, etc., to be observed through an ocular so that specific requirements are met. CONSTITUTION:The lens constitution of each lens group and various optical numerals are set as shown by inequalities I. Here, the focal lengths of ocular lenses are fT, fR, fF, and fE, the refractive indexes of the materials of the negative and positive lenses of the relay lens NN and NP, the Abbe numbers of the materials of the negative and positive lenses of the relay lens nuN and nuP, and the radius of curvature of the cemented surface of the cemented lens of the relay lens RA. Consequently, prescribed overall optical length is obtained and the secondary image formation type finder optical system is obtained which allows a finder image of high optical performance to be observed and suits to an electronic still camera, a video camera, etc.
Inventors:
KATO MASATAKE
Application Number:
JP31554987A
Publication Date:
June 26, 1996
Filing Date:
December 14, 1987
Export Citation:
Assignee:
CANON KK
International Classes:
G02B25/00; G02B23/14; G03B13/06; (IPC1-7): G02B25/00; G03B13/06
Domestic Patent References:
| JP55130577A |
Attorney, Agent or Firm:
Takanashi Yukio