EP0146177A1
Expired / Lapsed
EP
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Single collimator lens having one aspherical surface
Assignee: Koninklijke Philips NV
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Filing: 1984-12-03
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Granted: —
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Expires: 2004-12-03
Abstract
Abstract A collimator lens is described having a small numerical aperture and specific focal lengths. One of the surfaces of the lens is plane and the other surface has an aspherical profile defined by a series expansion comprising only a few even terms.
Inventors
- 👤 Albert Smid
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 17:55
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
123 words
A single collimator lens having one aspherical surface, characterized in that the second surface of the lens, which lens has a numerical aperture smaller than 0.25 and a focal length between approximately 16 mm and approximately 24 mm, is plane and the aspherical surface is defined by the expression where R is the distance from a point on the aspherical surface to the optical axis of the lens and Z is the distance between the projection of said point on the optical axis and the point of intersection of the optical axis and the aspherical surface, the coefficients E 2 , E 4 and E 6' which are functions of the refractive index n and the focal length f,in mn, being given by
Claim 2
Dependent Claim
123 words
A single collimator lens having one aspherical surface, characterized in that the second surface of the lens, which lens has a numerical aperture smaller than 0.25 and a focal length between approximately 16 mm and approximately 24 mm, is plane and the aspherical surface is defined by the expression where R is the distance from a point on the aspherical surface to the optical axis of the lens and Z is the distance between the projection of said point on the optical axis and the point of intersection of the optical axis and the aspherical surface, the coefficients E 2 , E 4 and E 6' which are functions of the refractive index n and the focal length f,in mn, being given by
Claim 3
Dependent Claim
53 words
A single collimator lens as claimed in Claim 1, characterized in that the lens comprises a glass piano convex body whose convex surface is provided with a layer of a transparent plastics with an aspherical outer profile, the refractive index of the plastics layer being substantially equal to that of the glass body.
Claim 4
Dependent Claim
25 words
A single collimator lens as claimed in Claim 2, characterized in that the plastics is a substance which cures under the influence of ultraviolet radiation.
Claim 5
Dependent Claim
62 words
An optical system producing a collimated radiation beam, which system comprises a tubular holder, a diode laser arranged in the holder, and a collimator lens system which is also arranged in the holder, characterized in that the collimator lens system comprises a single collimator lens as claimed in Claim 1, 2 or 3, whose plane surface is directed towards the diode laser.
Claim 6
Dependent Claim
41 words
An optical scanning unit for scanning an information surface in a record carrier by means of a radiation spot, which unit comprises an objective system for forming a diffraction-limited radiation spot, characterized by an optical system as claimed in Claim 4.
References Cited (Backward Citations)
US2530397A
Cited
DE1278131B
Cited
FR2271585A1
Cited
FR2352313A1
Cited
GB2087591A
Cited
FR2509478A1
Cited
GB2109583A
Cited
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