Patent US4657352A successfully refreshed from Google Patents.
US4657352A
Expired / Lapsed
US
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Image optical system including a non-spherical single lens
Assignee: Canon Inc
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Filing: 1985-09-30
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Granted: 1987-04-14
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Expires: 2005-09-30
Abstract
Abstract The imaging optical system according to the present invention comprises a non-spherical single lens having a first surface of a non-spherical shape in which the radius of curvature becomes gradually greater away from the optic axis and a planar second surface, and a parallel flat plate disposed adjacent to the second surface of the non-spherical single lens as required. The imaging optical system satisfies the following conditions: ##EQU1## where f is the focal length of the non-spherical single lens, d is the on-axis thickness of the single lens, n is the refractive index of the single lens, NA is the numerical aperture of the single lens, r 1 is the radius of curvature of the first surface of the single lens in the vicinity of the optic axis, and t is the thickness of the parallel flat plate.
Inventors
- 👤 Shigeyuki Suda
- 👤 Masayuki Suzuki
- 👤 Toshinori Ando
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:55
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/04; G02B13/00; G02B13/08; G02B13/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
An imaging optical system having a non-spherical single lens having a first surface of a non-spherical shape in which the radius of curvature becomes gradually greater away from the optic axis and a planar second surface, said imaging optical system satisfying the following conditions: ##EQU5## where f is the focal length of said single lens, d is the thickness of said single lens on the optic axis, n is the refractive index of said single lens, NA is the numerical aperture of said single lens and r 1 is the radius of curvature of said first surface in the vicinity of the optic axis.
Claim 2
Dependent Claim
104 words
An imaging optical system having a non-spherical single lens having a first surface of a non-spherical shape in which the radius of curvature becomes gradually greater away from the optic axis and a planar second surface, said imaging optical system satisfying the following conditions: ##EQU5## where f is the focal length of said single lens, d is the thickness of said single lens on the optic axis, n is the refractive index of said single lens, NA is the numerical aperture of said single lens and r 1 is the radius of curvature of said first surface in the vicinity of the optic axis.
Claim 3
Dependent Claim
16 words
An imaging optical system according to claim 1, wherein said numerical aperture NA is about 0.55.
Claim 4
Dependent Claim
72 words
An imaging optical system according to claim 1, wherein said first surface of a non-spherical shape is represented by ##EQU6## where the axis passing through the vertex of said first surface and perpendicular to the optic axis is the y-axis with respect to H, the optic axis is the x-axis, K is a cone constant, and B, C, D, E, A', B', C, and D' are coefficients representing the degrees of non-sphericity.
Claim 5
Dependent Claim
119 words
An imaging optical system having a non-spherical single lens having a first surface of a non-spherical shape in which the radius of curvature becomes gradually greater away from the optic axis and a planar second surface, and a parallel plate of a thickness t disposed adjacent to the second surface of said non-spherical single lens, said imaging optical system satisfying the following conditions: ##EQU7## where f is the focal length of said single lens, d is the thickness of said single lens, n is the refractive index of said single lens, NA is the numerical aperture of said single lens, and r 1 is the radius of curvature of said first surface in the vicinity of the optic axis.
Claim 6
Dependent Claim
119 words
An imaging optical system having a non-spherical single lens having a first surface of a non-spherical shape in which the radius of curvature becomes gradually greater away from the optic axis and a planar second surface, and a parallel plate of a thickness t disposed adjacent to the second surface of said non-spherical single lens, said imaging optical system satisfying the following conditions: ##EQU7## where f is the focal length of said single lens, d is the thickness of said single lens, n is the refractive index of said single lens, NA is the numerical aperture of said single lens, and r 1 is the radius of curvature of said first surface in the vicinity of the optic axis.
Claim 7
Dependent Claim
16 words
An imaging optical system according to claim 4, wherein said numerical aperture NA is about 0.55.
Claim 8
Dependent Claim
72 words
An imaging optical system according to claim 4, wherein said first surface of a non-spherical shape is represented by ##EQU8## where the axis passing through the vertex of said first surface and perpendicular to the optic axis is the y-axis with respect to H, the optic axis is the x-axis, K is a cone constant, and B, C, D, E, A', B', C' and D' are coefficients representing the degrees of non-sphericity.
References Cited (Backward Citations)
US934579A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |