发明名称 |
Pentagonal prism for camera viewfinder |
摘要 |
A pentagonal prism for use in a viewfinder of a single lens reflex camera is made of a glass whose refractive index and Abbe number are not less than 1.6 and 45, respectively. Effective optical path regions on a pair of roof surfaces of the prism are left transparent so that viewfinder light can be totally reflected at both of the roof surfaces. A light absorbing paint is coated in an upper front surface, a pair of said surfaces of the prism as well as at regions other than effective optical path region of the roof surfaces, a bottom light incident surface and a rear light exit surface of the prism. The light absorbing paint prevents the occurrence of ghost images in the view field of the viewfinder. New type glasses suited for the prism are proposed.
|
申请公布号 |
US4309078(A) |
申请公布日期 |
1982.01.05 |
申请号 |
US19800147532 |
申请日期 |
1980.05.07 |
申请人 |
MINOLTA CAMERA KABUSHIKI KAISHA |
发明人 |
HARA, KYOICHI;YAMAZAKI, YASUO;EGAWA, TAKESHI |
分类号 |
G03B13/26;G02B5/04;G02B27/00;(IPC1-7):G02B5/04;C03C3/10;C03C3/30 |
主分类号 |
G03B13/26 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|