Prism
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsIsamu Hirai, Etsuro Nishio, Yutaka Kamijo
Life of this patent
Estimating the term…
Abstract
A prism has a notch at a lower end of a third reflection plane of a pentagonal roof prism. The notch has a frosted wall, on which a transparent plate is adhered with adhesive. A miniature prism is adhered to the transparent plate with adhesive. The adhesive has photo-transmissibility, so that a transparent plane is formed between the pentagonal prism, the transparent plate and the miniature prism. Information displayed by an indication device is directed to an eyepiece optical system, via a mirror and the miniature prism.
Claims18
A prism mounted in an optical device, comprising:
- a main prism having a notch which is recessed relative to a surface adjacent thereto, said notch having an attaching wall which is frosted, said notch having a non-attaching wall other than said attaching wall, and said non-attaching wall is also frosted;
- and
- a sub-prism adhered to said attaching wall with adhesive having photo-transmissibility, said sub-prism being smaller than said main prism, and wherein said attaching wall, said non-attaching wall, and said sub-prism are constructed and arranged such that stray light incident on the non-attaching wall is scattered.
A pentagonal roof prism for a viewfinder optical system provided in a single reflex camera, comprising:
- an incident surface into which a light beam enters;
- a notch formed along a side of said incident surface, said notch having an attaching wall which is frosted, said notch having a non-attaching wall other than said attaching wall, and said non-attaching wall is also frosted;
- and
- a sub-prism adhered to said attaching wall with adhesive having photo-transmissibility, and wherein said attaching wall, said non-attaching wall, and said sub-prism are constructed and arranged such that stray light incident on the non-attaching wall is scattered, so that information is clearly indicated in the viewfinder.
A prism mounted in an optical device, comprising:
- a main prism having a notch which is recessed relative to a surface adjacent thereto, said notch having an attaching wall which is frosted;
- a sub-prism adhered to said attaching wall with adhesive having photo-transmissibility, said sub-prism being smaller than said main prism;
- and
- a transparent plate between said main prism and said sub-prism.
Dependencies are inferred from the claim text.