EP0416651A2
Expired / Lapsed
EP
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Apochromatic lens system
Assignee: Dainippon Screen Manufacturing Co Ltd
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Filing: 1990-09-07
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Granted: —
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Expires: 2010-09-07
Abstract
Abstract The present invention is directed to an apochromatic lens system which is corrected for chromatic aberration at three wavelengths. The apochromatic lens system includes a plane glass and a plane lens which are interchageable with each other. When the plane glass is disposed on the optical axis of a lens system, the plane glass cooperates with the lens system to be corrected for chromatic aberration at the first and second wavelengths. On the other hand, when the plane lens is disposed thereon in stead of the plane glass, the plane lens cooperates with the lens system to be corrected for chromatic aberration at the first wavelength and a third wavelength.
Inventors
- 👤 Yoshikazu Dainip. Screen Co. Ltd. 1-1 Kataoka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 16:22
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70241; G02; G02B; G02B13/00; G02B27/00; G02B27/0025
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
186 words
An apochromatic lens system comprising a lens system (L F , L R ) to be corrected for chromatic aberration, characterised by: a plane glass (1′) for cooperating with said lens system (L F , L R ) to correct for chromatic aberration at first and second wavelengths (g and h) when said plane glass (1′) is disposed on the optical axis of said lens system (L F , L R ); and a plane lens (1) formed by a plano-convex lens (1b) and a plano-concave lens (1a), a concave surface of said plano-concave lens (1a) facing a convex surface of said plano-convex lens (1b) whereby said plane lens (1) is identical to said plane glass (1′) in thickness, said plane lens (1) being interchangeable with said plane glass (1′), said plane lens cooperating with said lens system (L F , L R ) to correct for chromatic aberration at one of said first and second wavelengths (g and h) and a third wavelength (e) when said plane lens (1) is disposed on the optical axis of said lens system (L F , L R ).
Claim 2
Dependent Claim
186 words
An apochromatic lens system comprising a lens system (L F , L R ) to be corrected for chromatic aberration, characterised by: a plane glass (1′) for cooperating with said lens system (L F , L R ) to correct for chromatic aberration at first and second wavelengths (g and h) when said plane glass (1′) is disposed on the optical axis of said lens system (L F , L R ); and a plane lens (1) formed by a plano-convex lens (1b) and a plano-concave lens (1a), a concave surface of said plano-concave lens (1a) facing a convex surface of said plano-convex lens (1b) whereby said plane lens (1) is identical to said plane glass (1′) in thickness, said plane lens (1) being interchangeable with said plane glass (1′), said plane lens cooperating with said lens system (L F , L R ) to correct for chromatic aberration at one of said first and second wavelengths (g and h) and a third wavelength (e) when said plane lens (1) is disposed on the optical axis of said lens system (L F , L R ).
Claim 3
Dependent Claim
61 words
An apochromatic lens system according to claim 1, wherein one of said plano-convex and plano-concave lenses (1b or 1a) is made of a first glass material, and the other (1a or 1b) is made of a second glass material having approximately the same refractive index as said first glass material but having a dispersion value different from said first glass material.
Claim 4
Dependent Claim
25 words
An apochromatic lens system according to claim 2, wherein said first glass material is the same as the glass material of said plane glass (1′).
Claim 5
Dependent Claim
34 words
An apochromatic lens system according to any one of claims 1 to 3, wherein said convex and concave surfaces of said plano-convex and plano-concave lens (1b and 1a) have the same radius of curvature.
Claim 6
Dependent Claim
19 words
An apochromatic lens system according to claim 4, wherein said convex and concave surfaces are joined to each other.
Claim 7
Dependent Claim
31 words
An apochromatic lens system according to any preceding claim, wherein said lens system (L F , L R ) comprises first (L F ) and second (L R ) lens groups.
Claim 8
Dependent Claim
34 words
An apochromatic lens system according to claim 6, wherein said plane glass (1′) and said plane lens (1) are interchangeably disposed between said first and second lens groups (L F and L R ).
Claim 9
Dependent Claim
31 words
An apochromatic lens system according to any preceding claim, wherein said plane glass (1′) is selectively movable along the optical axis of said lens system (L F , L R ).
Claim 10
Dependent Claim
31 words
An apochromatic lens system according to any preceding claim, wherein said plane lens (1) is selectively movable along the optical axis of said lens system (L F , L R ).
References Cited (Backward Citations)
No citation records indexed.
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