Patent US4848885A successfully refreshed from Google Patents.
US4848885A
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Preobjective scanning system
Assignee: Intellectual Ventures I LLC
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Filing: 1988-05-09
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Granted: 1989-07-18
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Expires: 2008-05-09
Abstract
Abstract A preobjective scanning optical system for use with a rotating mirror scanner employing LEDs or lasers to electronically reproduce photographs. The optical system includes a doublet disposed before the mirror and a triplet disposed after the mirror. Instead of collimating, the first optical system along with the mirror forms a virtual, image of the LEDs or lasers which travels along a curved path as the scanner rotates and includes a first and a second lens which, in combination, correct the image for on-axis spherical and axial color aberrations. The triplet has net positive power and its three lenses, in combination, correct for off-axis aberrations such as astigmatism, coma, and lateral color aberration but can be under-corrected for field curvature because its object is the curved virtual image.
Inventors
- 👤 Peter P. Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:29
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/0025; G02B27/0031; G02B26/00; G02B26/08; G02B26/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
90 words
A preobjective optical system for use with scanning means to scan a line with a focused image of light from a stationary source, said preobjective scanning optical system comprising: a first group of lenses disposed ahead of the scanning means for forming a virtual, image of the source which travels along a curved path as the scanning means rotates; and a second group of lenses of net positive power located after the scanning means and structured to focus said image into a straight scan line as the scanning means rotates.
Claim 2
Dependent Claim
90 words
A preobjective optical system for use with scanning means to scan a line with a focused image of light from a stationary source, said preobjective scanning optical system comprising: a first group of lenses disposed ahead of the scanning means for forming a virtual, image of the source which travels along a curved path as the scanning means rotates; and a second group of lenses of net positive power located after the scanning means and structured to focus said image into a straight scan line as the scanning means rotates.
Claim 3
Dependent Claim
16 words
The preobjective scanning optical system of claim 1 wherein said first group corrects for on-axis aberrations.
Claim 4
Dependent Claim
21 words
The preobjective scanning optical system of claim 1 wherein said first group corrects for on-axis spherical aberration and on-axis axial color.
Claim 5
Dependent Claim
16 words
The preobjective scanning optical system of claim 1 wherein said second group corrects for off-axis aberrations.
Claim 6
Dependent Claim
19 words
The preobjective scanning optical system of claim 1 wherein said second group corrects for astigmatism, coma, and lateral color.
Claim 7
Dependent Claim
75 words
The preobjective scanning optical system of claim 5 wherein: said first group comprises a doublet wherein the first lens is a negative element and the second lens is a positive element, and the doublet has a net positive power and is itself corrected for coma over the field of the light source(s); and said second group comprises a triplet having a first lens that is a negative and second and third lenses that are positive.
Claim 8
Dependent Claim
18 words
The preobjective scanning optical system of claim 6 which further comprises a stop disposed before the scanning means.
Claim 9
Dependent Claim
28 words
The preobjective scanning optical system of claim 7 in which said stop has a larger opening perpendicular to the scanning direction than its opening in the scanning direction.
Claim 10
Dependent Claim
16 words
The preobjective scanning optical system of claim 8 wherein said stop has a substantially elliptical shape.
References Cited (Backward Citations)
US4241257A
Cited
US4497546A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |