Patent US4415238A successfully refreshed from Google Patents.
US4415238A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single lens having one spherical and one aspherical refractive surface
Assignee: US Philips Corp
•
Filing: 1981-10-02
•
Granted: 1983-11-15
•
Expires: 2001-10-02
Abstract
Abstract A lens having a spherical surface and an aspherical surface curved relative to each other to minimize coma for a large diffraction-limited field and a large numerical aperture.
Inventors
- 👤 Josephus J. M. Braat
- 👤 Jan Haisma
- 👤 Gijsbert Prast
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:48
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
105 words
A single lens having one spherical and one aspherical refractive surface, characterized in that the spherical refractive surface and the aspherical refractive surface are in a relationship with each other which is represented by a set of straight lines in which the expressions for a and b are: ##EQU7## where c 1 is the curvature of the aspherical surface at its intersection with the optical axis, c 2 is the curvature of the spherical surface, d is the thickness of the lens, n is the refractive index, f is the focal length and NA is the numerical aperture, while 0.3≦NA≦0.5; 1.5≦n≦2.0 and the magnification V≦0.1.
Claim 2
Dependent Claim
105 words
A single lens having one spherical and one aspherical refractive surface, characterized in that the spherical refractive surface and the aspherical refractive surface are in a relationship with each other which is represented by a set of straight lines in which the expressions for a and b are: ##EQU7## where c 1 is the curvature of the aspherical surface at its intersection with the optical axis, c 2 is the curvature of the spherical surface, d is the thickness of the lens, n is the refractive index, f is the focal length and NA is the numerical aperture, while 0.3≦NA≦0.5; 1.5≦n≦2.0 and the magnification V≦0.1.
References Cited (Backward Citations)
US4027952A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-14 | 1987-05-16 | 1987-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-14 | 1991-05-16 | 1991-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-14 | 1995-05-16 | 1995-11-15 | $7700.00 | Window Closed / Lapsed |