Patent US3825322A successfully refreshed from Google Patents.
US3825322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Illumination system
Assignee: Gretag AG
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Filing: 1972-12-29
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Granted: 1974-07-23
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Expires: 1992-12-29
Abstract
Abstract An optical system is provided which in conjunction with a light source is used to illuminate an object whose reflective properties are required to be measured. The optical system comprises a condenser lens having first and second spherical surfaces, the first having an annular reflective surface on its periphery and the second an annular reflective surface at its central portion. A positive lens is mounted in the aperture of the reflective annular surface on the second surface of the condenser lens which has a third spherical surface surrounding the second surface. The center of curvature of the third surface defines the position of the object which is illuminated by light entering the first surface, being reflected from the reflective surface on the second surface back through the condenser, reflected from the reflective surface on the first surface back through the condenser lens to exit from the third surface to be focussed on the object. Light reflected by the object is focussed by the positive lens through the condenser on to a light measuring system.
Inventors
- 👤 F Mast
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:12
CPC Classifications
G; G02; G02B; G02B17/00; G02B17/08; G02B17/0896; G02B17/002; G02B17/0804; G02B17/0808; G02B17/0856; G02B17/086; G02B21/00; G02B21/02; G02B21/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
287 words
An optical system comprising: a. a condenser lens having first and second spherical surfaces which are concentrical one to the other and a third spherical surface surrounding said second spherical surface and having a radius of curvature greater than that of said second spherical surface so that the centre of curvature of said third spherical surface lays in a plane at which an object is to be placed for illumination by light incident on said first spherical surface; b. a first annular spherical reflecting surface facing the peripheral portion of said first spherical surface so that the axis of said reflecting surface is coincident with the axis of said condenser lens; c. a second annular spherical reflecting surface facing the central portion of the second surface so that the axis of said second reflecting surface is coincident with the axis of said condenser lens, the positions of the reflecting surfaces being such that light entering said first surface travels through said condenser lens, is reflected by said second reflecting surface back through the condenser lens to impinge on said first reflecting surface which reflects the light back through said condenser lens to exit through said third surface and be focussed at the centre of curvature thereof; and d. a positive lens having one surface facing said second spherical surface to focus light through the aperture in the second annular reflecting surface and mounted so that the axis of said lens is coincident with the axis of said condenser lens, said first and second annular reflecting surfaces being concentrically disposed and the reflective index of the condenser lens and the radii of curvature of said first, second and third surfaces being chosen so that said system is aplanatic.
Claim 2
Dependent Claim
287 words
An optical system comprising: a. a condenser lens having first and second spherical surfaces which are concentrical one to the other and a third spherical surface surrounding said second spherical surface and having a radius of curvature greater than that of said second spherical surface so that the centre of curvature of said third spherical surface lays in a plane at which an object is to be placed for illumination by light incident on said first spherical surface; b. a first annular spherical reflecting surface facing the peripheral portion of said first spherical surface so that the axis of said reflecting surface is coincident with the axis of said condenser lens; c. a second annular spherical reflecting surface facing the central portion of the second surface so that the axis of said second reflecting surface is coincident with the axis of said condenser lens, the positions of the reflecting surfaces being such that light entering said first surface travels through said condenser lens, is reflected by said second reflecting surface back through the condenser lens to impinge on said first reflecting surface which reflects the light back through said condenser lens to exit through said third surface and be focussed at the centre of curvature thereof; and d. a positive lens having one surface facing said second spherical surface to focus light through the aperture in the second annular reflecting surface and mounted so that the axis of said lens is coincident with the axis of said condenser lens, said first and second annular reflecting surfaces being concentrically disposed and the reflective index of the condenser lens and the radii of curvature of said first, second and third surfaces being chosen so that said system is aplanatic.
Claim 3
Dependent Claim
27 words
A system according to claim 1 wherein the first and second reflecting surfaces are vapour deposited on the first and second surfaces of the condenser lens respectively.
Claim 4
Dependent Claim
29 words
A system according to claim 1 wherein said second reflecting surface is deposited on that surface of said positive lens facing the second spherical surface of said condenser lens.
Claim 5
Dependent Claim
30 words
A system according to claim 3 wherein the aperture in said second annular reflecing surface forms a stop for the lens system comprising the positive lens and said condenser lens.
Claim 6
Dependent Claim
214 words
An optical system according to claim 1 in combination with a condenser system comprising: a. a first lens having first and second spherical surfaces which are parallel one to the other; b. a first annular spherical reflecting surface on the peripheral portion of said first lens so that the axis of the reflecting surface is coaxial with the axis thereof; and c. a second spherical reflecting surface on the central portion of the second surface of said first lens so that the axis of the second reflecting surface is coaxial with the axis thereof; means mounting the condenser system so its optical axis is coaxial with that of said condenser lens and the first surface of the latter is convex with respect to the first surface of the first lens; a stop between said condenser lens and said first lens; a light source on said optical axis and facing said second spherical surface of the first lens which is concave with respect to said source; a reflective surface between said stop and the first surface of said condenser lens; and means for analysing light reflected from an object placed at the centre of curvature of the third surface of said condenser lens and passed through said positive lens and reflected by said reflective surface.
Claim 7
Dependent Claim
44 words
The combination according to claim 5 wherein said analysing means includes filters to split up the light reflected by said object into different colours and a plurality of photosensitive means each responsive to a different one of said colours to provide an output signal.
Claim 8
Dependent Claim
38 words
A measuring head comprising a plurality of optical systems according to claim 1, a light source and means for imaging said source onto the first surfaces of each of the condenser lenses of said plurality of optical systems.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |