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US 5,293,542 AGranted
Iris for video camera
AssigneeSony Corporation
InventorsKoichi Ise, Yoshinori Tomita
Life of this patent
Estimating the term…
Abstract
A video camera in which an iris in an optical system is composed of a plurality of diaphragms, and at least two of the plurality of diaphragms are respectively provided with a light amount limiting filter such that the light amount limiting filters attached on the at least two diaphragms completely surround a transparent portion when the iris is half closed, to thereby provide satisfactory characteristics of the optical system when the iris is half closed.
Claims3
A video camera for converting an optical image arriving at an imager through an optical system including lenses and an iris to a video signal,
- wherein said iris is composed of two opaque diaphragms of arcuate shape mounted for relative pivotal movement toward or away from each other and having facing cut-away portions thereon and light transmission limiting, neutral density filters having predetermined identical light limiting characteristics respectively attached on said two diaphragms at said cut-away portions so that said light transmission limiting, neutral density filters are likewise mounted for relative movement toward or away from each other;
- and
- said light transmission limiting, neutral density filters attached on said two diaphragms being arranged to completely surround a central open portion of said iris so that light passes through said central open portion and said light transmission limiting, neutral density filters at a first position when said iris is partially closed and said two light transmission limiting, neutral density filters overlap each other at varying degrees at a central portion of said iris so that light passes only through said light transmission limiting, neutral density filters when said iris is at a more fully closed position.
Dependencies are inferred from the claim text.