Pentax Corporation

Atsuo Kabeta

Tetsuya Abe

Hidefumi Kaneko

Kazuhiro Yamada

Akihiro Sugiyama

A superimpose-plate is put on a focusing glass, on which a subject image obtained through the photographing optical system is formed. The superimpose-plate and the focusing glass are provided in an incident opening of a hollow pentagonal mirror. The superimpose-plate comprises a plurality of micro-prisms that are formed on the superimpose-plate. Each of the micro-prisms shows a triangle in a cross-section. The vertical angle of the triangle is identical in each of the micro-prisms. A ridgeline of each of the micro-prisms is parallel to the right-left direction of the picture plane of the view finder.

Superimpose-plate for view finder

Disclosed is a lens, which has a convex surface, a concave surface and a flange that is formed around the lens to be projected in a radial direction perpendicular to an optical axis and to be continued from the convex surface. The flange is provided with a groove formed on the side of the convex surface that extends from the outer edge of the convex surface toward the outer edge of the flange. When the lens is pulled up from a solution of coating material, the unnecessary solution that collects at a lower area of the convex surface drips from the lens through the groove. This prevents a formation of a puddle on the convex surface.

Growing community of inventors

Tochigi, Japan

Atsuo Kabeta