Focussing plate
AssigneeMinolta Camera Kabushiki Kaisha
InventorsKatsuhiro Ise, Yoshio Kuramoto, Yasuo Yamazaki
Life of this patent
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Abstract
A large number of cones such as circular cones or pyramids, or conical recesses are regularly uniformly distributed and formed on a surface of a transparent focussing plate. Each cone or conical recess has a large number of fine irregularities on the sloping surface thereof to thereby diffuse the light passing through the sloping surface.
Claims17
In a single lens reflex camera, a focussing plate comprising a transparent plate on a surface of which is regularly formed a large number of conical surfaces;
- the improvement wherein said each conical surface has a large number of irregularities which are fine enough not to spoil the conicity of said respective conical surfaces.
In a single lens reflex camera a focussing device comprising a transparent base member having distributed on a face thereof a plurality of surfaces convergent from enlarged bases to respective apices and characterized in that said surfaces are each light diffusing and have fine light diffusing irregularities formed thereon.
Dependencies are inferred from the claim text.