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US 5,589,989 AGranted
Compact objective lens system
AssigneeEastman Kodak Company
InventorsLee R. Estelle, William T. Goosey, Jr.
Life of this patent
Estimating the term…
Abstract
A compact objective lens with a diaphragm arranged behind the lens system suitable for use in very compact photographic cameras. The objective lens comprises a plurality of components arranged in a triplet or a triplet type configuration and is capable of covering at least a 55 degree field of view.
Claims34
A lens system comprising from an object side:
- a first positive power meniscus lens component having a foremost lens surface convex to the object side;
- a second bi-concave lens component engaging said first lens component and defining with said first lens component an airspace separating said second lens component from said first component;
- a third bi-convex lens component engaging said second lens component and defining with said second lens component an airspace between said third lens component from said second lens component;
- and
- a diaphragm arranged behind the rear-most lens element of the lens system, wherein all of the airspaces between said lens components are so arranged that there exists between all of adjacent lens components an edge contact located only at points located within the region from over 0.0 mm at a position to sufficiently eliminate stray light to about 2 mm beyond clear aperture diameter, and wherein the lens system fulfills the following conditions:
- ##EQU8## where:
- f is the composite focal length of the lens system;
- .SIGMA.d is the distance from the vertex of the foremost lens surface to the vertex of the last lens surface;
- N.sub.1 represents the refractive index of a positive lens element forming the first lens component;
- N.sub.2 represents the refractive index of a negative lens element forming the second lens component;
- and
- N.sub.3 represents the refractive index of a positive lens element forming the third lens component.
9 more elements
A lens system comprising a plurality lens of components arranged in order from an object side:
- a first positive power meniscus lens component having an object type surface convex to the object side;
- a second bi-concave lens component engaging said first lens component and having an airspace separating said second lens component from said first component;
- a third bi-convex lens component engaging said second lens component and having an airspace separating said third lens component from said second lens component, said plurality of lens components having radii of curvature, thicknesses and airspaces to enable the lens to cover at least 55 degree field of view, wherein all of the airspaces between said lens components are so arranged that there exists between all of adjacent lens components an edge contact located only at points located within the region from over 0.0 mm at a position to sufficiently eliminate stray light to about 2 mm beyond clear aperture diameter;
- and
- a diaphragm arranged behind a rear-most lens element of a lens system, and wherein said lens system fulfills the following conditions:
- T.sub.1 .gtoreq.2d.sub.1
- and
- T.sub.3 .gtoreq.2d.sub.2.
- where:
- d.sub.1 is an airspace between a first and a second lens element;
- d.sub.2 is an airspace between the second and a third lens element;
- T.sub.1 is the thickness of the first lens element;
- and
- T.sub.3 is the thickness of the third lens element.
11 more elements
A lens system comprising in order from an object side:
- a first positive power lens component;
- a negative power lens component located between and airspaced from said first positive power lens component and a second positive power lens component;
- the second positive power lens component located behind said negative power lens component;
- an aperture stop, said aperture stop located on an outer side of one of said positive power lens components;
- and
- wherein all of airspaces between said lens components are so arranged that there exists an edge contact between all of the adjacent lens components so that there are contacting lens surfaces and said edge contact exists only at points located within the region from 0.0 mm at a position to sufficiently eliminate stray light to less than 3 mm beyond a clear aperture diameter of each of said contacting lens surfaces.
3 more elements
A compact lens system for use in a compact photographic camera comprising:
- a plurality of lens elements forming lens components and spaced in a close proximity to one another, said plurality of lens elements having sufficient powers and spacings to enable said lens system to cover a field of view of at least 55 degrees, said plurality of lens elements including at least one positive power lens element and one negative power lens element wherein an airspace between said positive power lens element and said negative power lens element is smaller than a thickness of said positive lens element, wherein all of airspaces between the lens components are so arranged that there exists between all adjacent lens components an edge contact located only at points located within the region from over 0.0 mm at a position to sufficiently eliminate stray light to about 2 mm beyond clear aperture diameter;
- and
- the lens system being suited for use in a compact camera and satisfying the following parameters:
- 20.ltoreq.f.ltoreq.30
- 5.ltoreq.BF.ltoreq.24.85
- 2.ltoreq.f/No..vertline..sub.min. .ltoreq.5.6,
- where f is the focal length of the lens system, BF is the back focus of the lens system and f/No..vertline..sub.min. is the F-number that the lens system performs at without being stopped down.
4 more elements
A compact lens system for use as a taking lens in a compact camera, the lens system comprising no more than four lens elements centered on an optical axis and grouped together in a 3 lens component lens group with an aperture stop arranged outside of the lens group;
- said lens elements arranged so that there is edge contact among all of the adjacent and uncemented lens elements and the lens elements have cooperating edge surfaces to self-center said lens elements, wherein all of airspaces between said adjacent and uncemented lens elements are so arranged that said edge contact exits only at points located within a region from over 0.0 mm at a position to eliminate stray light to about 2 mm beyond clear aperture diameter, said lens components being a front positive power lens component, a negative power lens component and a rear positive power lens component wherein said rear positive power lens component is a cemented doublet comprising one positive lens element and one negative lens element.
A compact lens system for use in a compact camera comprising:
- a plurality of optical elements spaced in close proximity to one another, said plurality of lens elements having sufficient powers and spacings to enable said lens system to cover a field of view of at least 55 degrees, said plurality of lens elements including at least one positive lens element and one negative lens element wherein an airspace between said positive lens element and said negative lens element is smaller than a thickness of said positive lens element, wherein all of airspaces between all of adjacent lens elements are so arranged that there exists an edge contact located only at points located within the region from over 0.0 mm at a position to sufficiently eliminate stray light to about 2 mm beyond clear aperture diameter;
- and
- the lens system being suited for use in a compact camera and satisfying the following parameters:
- 2.ltoreq.f/No..vertline..sub.min. .ltoreq.5.6
- 20.ltoreq.f.ltoreq.30,
- where:
- f is the focal length of the lens system;
- and
- f/No..vertline..sub.min. is the F-number that the lens system performs at without being stopped down.
6 more elements
A compact lens system for use in a compact photographic camera comprising:
- a plurality of lens elements forming a plurality of lens components and spaced in a close proximity to one another, said plurality of lens elements having sufficient powers and spacings to enable said lens system to cover a field of view of at least 50 degrees, said plurality of lens elements including at least one positive power lens element and one negative power lens element wherein an airspace between said positive power lens element and said negative power lens element is smaller than a thickness of said positive lens element, wherein all of airspaces between the lens components are so arranged that there exists between all adjacent lens components an edge contact located only at points located within the region from over 0.0 mm at a position to sufficiently eliminate stray light to about 2 mm beyond clear aperture diameter;
- and
- the lens system being suited for use in a compact camera and satisfying the following parameters:
- 2.ltoreq. f.ltoreq.30
- 5.ltoreq.BF.ltoreq.24.25
- 3.ltoreq.f/No..vertline..sub.min. .ltoreq.16,
- where f is the focal length of the lens system, BF is the back focus of the lens system, all distances are in mm, and the f/No. is the f number of the lens system.
4 more elements
Dependencies are inferred from the claim text.