US4632520A
Expired / Lapsed
US
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Plastic objective lens system adapted for correction for temperature
Assignee: JUJI PHOTO OPTICAL Co Ltd 1-234 UETAKE-MACHI OHMIYA-SHI SAITAMA-KEN JAPAN
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Filing: 1984-05-15
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Granted: 1986-12-30
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Expires: 2004-05-15
Abstract
Abstract A plastic objective lens system comprises at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than the absolute value of the coefficient of the plastic material constituting the convex lens. A reflecting surface concave to the object and image side may be positioned at the rear of the convex lens and concave lens. The plastic objective lens system decreases fluctuation of the focal length and the conjugate distance due to a change in temperature while aberration is minimized.
Inventors
- 👤 Hiromitsu Yamakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:12
CPC Classifications
G; G02; G02B; G02B9/00; G02B9/34; G02B9/36; G02B9/44; G02B13/00; G02B17/00; G02B17/08; G02B17/0856
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
124 words
A plastic objective lens system adapted for correction for temperature comprising at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than said absolute value of the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens, said plastic objective lens system satisfying the condition (1); ##EQU2## wherein dn1/dt and dn2/dt respectively denote the coefficients of change in refractive index with temperature of the plastic materials constituting said convex lens and said concave lens.
Claim 2
Dependent Claim
124 words
A plastic objective lens system adapted for correction for temperature comprising at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than said absolute value of the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens, said plastic objective lens system satisfying the condition (1); ##EQU2## wherein dn1/dt and dn2/dt respectively denote the coefficients of change in refractive index with temperature of the plastic materials constituting said convex lens and said concave lens.
Claim 3
Dependent Claim
54 words
A plastic objective lens system as defined in claim 1 wherein the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens is -8.5×10 -5 /°C., and the coefficient of change in refractive index with temperature of the plastic material constituting said concave lens is -13.3×10 -5 /°C.
Claim 4
Dependent Claim
205 words
An in-mirror lens type plastic objective lens system adapted for correction for temperature for use in copying, projection or the like at a finite image formation magnification, the objective lens system comprising a reflecting surface concave to the object and image side, at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than said absolute value of the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens, said convex lens and said concave lens being positioned on the object and image side in front of said reflecting surface, so that an image formation light beam passes twice midway from the object to said concave reflecting surface and midway from said concave reflecting surface to the image side, said plastic objective lens system satisfying the condition (1); ##EQU3## wherein dn1/dt and dn2/dt respectively denote the coefficients of change in refractive index with temperature of the plastic materials constituting said convex lens and said concave lens.
Claim 5
Dependent Claim
205 words
An in-mirror lens type plastic objective lens system adapted for correction for temperature for use in copying, projection or the like at a finite image formation magnification, the objective lens system comprising a reflecting surface concave to the object and image side, at least one convex lens constituted of a plastic material exhibiting a relatively small absolute value of the coefficient of change in refractive index with temperature, and at least one concave lens constituted of a plastic material exhibiting an absolute value of the coefficient of change in refractive index with temperature, which is larger than said absolute value of the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens, said convex lens and said concave lens being positioned on the object and image side in front of said reflecting surface, so that an image formation light beam passes twice midway from the object to said concave reflecting surface and midway from said concave reflecting surface to the image side, said plastic objective lens system satisfying the condition (1); ##EQU3## wherein dn1/dt and dn2/dt respectively denote the coefficients of change in refractive index with temperature of the plastic materials constituting said convex lens and said concave lens.
Claim 6
Dependent Claim
54 words
A plastic objective lens system as defined in claim 3 wherein the coefficient of change in refractive index with temperature of the plastic material constituting said convex lens is -8.5×10 -5 /°C., and the coefficient of change in refractive index with temperature of the plastic material constituting said concave lens is -13.3×10 -5 /°C.
References Cited (Backward Citations)
US3205774A
Cited
US4384766A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |