US4674843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gradient index lens
Assignee: Canon Inc
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Filing: 1986-02-19
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Granted: 1987-06-23
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Expires: 2006-02-19
Abstract
Abstract A gradient index lens includes first and second flat end faces. A refractive index N(γ) at a position deviated by a distance γ from an optical axis of the lens is given as N(γ)=N.sub.0 +N.sub.1 γ.sup.2 +N.sub.2 γ.sup.4 + . . . for N 1 <0 where N 0 , N 1 , N 2 , . . . are constants, and the following conditions are satisfied: ##EQU1## where f is a focal length of the lens, a is an effective lens diameter, Sk' is a work distance, and λ is a wavelength in units of microns.
Inventors
- 👤 Takeshi Baba
- 👤 Jun Hattori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:15
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/0087
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 words
A gradient index lens comprising: a first flat end face; and a second flat end face, wherein a refractive index N(γ) at a position deviated by a distance γ from an optical axis of said lens is given as N(γ)=N.sub.0 +N.sub.1 γ.sup.2 +N.sub.2 γ.sup.4 +. . . for N 1 <0 where N 0 , N 1 , N 2 , . . . are constants, and the following conditions are satisfied: ##EQU10## where f is a focal length of said lens, a is a substantial lens diameter, Sk' is a work distance, and λ is a wavelength in units of microns.
Claim 2
Dependent Claim
102 words
A gradient index lens comprising: a first flat end face; and a second flat end face, wherein a refractive index N(γ) at a position deviated by a distance γ from an optical axis of said lens is given as N(γ)=N.sub.0 +N.sub.1 γ.sup.2 +N.sub.2 γ.sup.4 +. . . for N 1 <0 where N 0 , N 1 , N 2 , . . . are constants, and the following conditions are satisfied: ##EQU10## where f is a focal length of said lens, a is a substantial lens diameter, Sk' is a work distance, and λ is a wavelength in units of microns.
Claim 3
Dependent Claim
10 words
A lens according to claim 1, wherein N 0 ≧1.60.
Claim 4
Dependent Claim
8 words
A lens according to claim 1, wherein Sk'/f≦0.6.
Claim 5
Dependent Claim
13 words
A lens according to claim 1, wherein a condition below is satisfied: ##EQU11##
Claim 6
Dependent Claim
20 words
A lens according to claim 1, wherein the wavelength λ is a peak wavelength when a wavelength distribution is wide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-22 | 1990-12-22 | 1991-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-22 | 1994-12-22 | 1995-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-22 | 1998-12-22 | 1999-06-23 | $7700.00 | Window Closed / Lapsed |