US4941721A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Raster scanning system utilizing overfilled polygon facet design
Assignee: Xerox Corp
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Filing: 1989-06-01
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Granted: 1990-07-17
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Expires: 2009-06-01
Abstract
Abstract In a raster output scanning (ROS) printer, an overfilled polygon design is enabled by using a high power laser diode to compensate for low efficiency of an overfilled design and by using an aspheric lens assembly to provide a flat beam illumination profile at each polygon facet.
Inventors
- 👤 Martin E. Banton
- 👤 Michael E. Harrigan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:02
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/09; G02B27/0927; G02B26/00; G02B26/08; G02B26/10; G02B26/12; G02B26/125; G02B27/0938; G02B27/0988
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
142 words
A raster input scanning system utilizing an overfilled polygon facet design for forming lens images at a photosensitive medium comprising: means for providing a beam of radiant energy, means for modulating said energy beam in response to electrical signals, means for expanding the modulated beam, a polygon having at least one reflective facet positioned in the optical path of said modulated beam and adapted to scan said spot across said medium, and an aspheric lens system positioned between said modulating means and said polygon, said aspheric lens adapted to transform the modulated output beam into a beam having a generally flat uniform intensity profile which overfills said facet as it rotates therethrough, said aspheric lens system comprising a first negative lens element and a second positive lens element each of said lens elements having one aspherical surface, and one generally planar surface.
Claim 2
Dependent Claim
142 words
A raster input scanning system utilizing an overfilled polygon facet design for forming lens images at a photosensitive medium comprising: means for providing a beam of radiant energy, means for modulating said energy beam in response to electrical signals, means for expanding the modulated beam, a polygon having at least one reflective facet positioned in the optical path of said modulated beam and adapted to scan said spot across said medium, and an aspheric lens system positioned between said modulating means and said polygon, said aspheric lens adapted to transform the modulated output beam into a beam having a generally flat uniform intensity profile which overfills said facet as it rotates therethrough, said aspheric lens system comprising a first negative lens element and a second positive lens element each of said lens elements having one aspherical surface, and one generally planar surface.
Claim 3
Dependent Claim
25 words
The scanning system of claim 1 wherein said aspheric lens transforms said modulated output into a collimated beam having a curved profile with peaked edges.
Claim 4
Dependent Claim
46 words
The scanning system of claim 1 wherein such aspheric lens system has the following parameters: ______________________________________
REFRACTIVE
INDEX
LENS RADIUS (nm) SPACING (nm) (GLASS)
______________________________________
25R.sub.1
-22.07581 S.sub.1 = 10.16
1.618
25R.sub.2
127.0000 S.sub.2 = 88.90
1.000
27R.sub.3
73.43002 S.sub.3 = 15.24
1.618
27R.sub.4
α
______________________________________
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) | 1993-07-16 | 1994-01-15 | 1994-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-16 | 1998-01-15 | 1998-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-16 | 2002-01-15 | 2002-07-17 | $7700.00 | Window Closed / Lapsed |