Patent US6280035B1 successfully refreshed from Google Patents.
US6280035B1
Expired / Lapsed
US
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Lens design to eliminate color fringing
Assignee: Duke University
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Filing: 1998-10-23
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Granted: 2001-08-28
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Expires: 2018-10-23
Abstract
Abstract Projection lenses and projection lens systems are telecentric between an illumination subsystem and a set of imagers. The lenses and systems can exhibit color fringing correction, uniform imager illumination, athermalization, and component articulation for improved imaging. The lenses and systems may be employed in displays, such as folded displays that have decreased footprint size, but long effective projection lengths.
Inventors
- 👤 Biljana Tadic-Galeb
- 👤 Robert E. Fischer
- 👤 Neil L. Condra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:05
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/22; G03; G03B; G03B21/00; G03B21/005; G03B21/006; G02B27/00; G02B27/0025; G02B3/00; G02B3/0087
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
116 words
A projection lens apparatus, comprising: a front lens unit; a back lens unit optically coupled to said front lens unit; a linear reflecting polarizer optically coupled to the front lens unit and the back lens unit that receives illumination light and directs the illumination light to the back lens unit; a chromatic separating element optically coupled to the linear reflecting polarizer that separates the illumination light into color separated light; an imager optically coupled to the chromatic separating element and adapted to impart an image on a portion of the color separated light; and a field lens adapted to change the magnification of the portion of the color separated light to substantially correct a chromatic aberration.
Claim 2
Dependent Claim
116 words
A projection lens apparatus, comprising: a front lens unit; a back lens unit optically coupled to said front lens unit; a linear reflecting polarizer optically coupled to the front lens unit and the back lens unit that receives illumination light and directs the illumination light to the back lens unit; a chromatic separating element optically coupled to the linear reflecting polarizer that separates the illumination light into color separated light; an imager optically coupled to the chromatic separating element and adapted to impart an image on a portion of the color separated light; and a field lens adapted to change the magnification of the portion of the color separated light to substantially correct a chromatic aberration.
Claim 3
Dependent Claim
24 words
The projection lens apparatus of claim 1 , wherein the chromatic separating element is adapted to mix the image light with other image light.
Claim 4
Dependent Claim
19 words
The projection lens apparatus of claim 1 , wherein the field lens is adjacent to the chromatic separating element.
Claim 5
Dependent Claim
17 words
The projection lens apparatus of claim 1 , wherein the field lens is adjacent to the imager.
Claim 6
Dependent Claim
19 words
The projection lens apparatus of claim 1 , wherein the field lens is adapted to substantially correct lateral color.
Claim 7
Dependent Claim
37 words
The projection lens apparatus of claim 1 , wherein the field lens is adapted to adjust magnification of the portion of the color separated light relative to the magnifications of other portions of the color separated light.
Claim 8
Dependent Claim
25 words
The projection lens apparatus of claim 1 , wherein the field lens is adapted to compensate for chromatic separating characteristics of the chromatic separating element.
Claim 9
Dependent Claim
26 words
The projection lens apparatus of claim 1 , further comprising another imager adapted to direct other portions of the color separated light as other image light.
Claim 10
Dependent Claim
25 words
The projection lens apparatus of claim 8 , wherein the chromatic separating element is adapted to mix the image light and the other image light.
Claim 11
Dependent Claim
30 words
The projection lens apparatus of claim 9 , wherein the image light and the other image light mixed by the chromatic separating element are projected to form a color image.
Claim 12
Dependent Claim
41 words
The projection lens apparatus of claim 1 , wherein the linear reflecting polarizer is adapted to direct the illumination light substantially in a first polarization toward the back lens unit and to direct the image light substantially in a second polarization.
Claim 13
Dependent Claim
38 words
The projection lens apparatus of claim 1 , wherein the imager is adapted to receive the portion of the color separated light substantially in a first polarization and to direct the image light substantially in a second polarization.
Claim 14
Dependent Claim
28 words
The projection lens apparatus of claim 1 , wherein the image light passes through the linear reflecting polarizer and projects from the front lens to a display screen.
Claim 15
Dependent Claim
18 words
The projection lens apparatus of claim 1 , wherein the linear reflecting polarizer comprises a substantially nonabsorbing polarizer.
Claim 16
Dependent Claim
17 words
The projection lens apparatus of claim 1 , wherein the linear reflecting polarizer comprises multilayer optical film.
Claim 17
Dependent Claim
33 words
The projection lens apparatus of claim 1 , wherein the imager is adapted to direct the image light substantially retarded by one-half wave with respect to the portion of the color separated light.
Claim 18
Dependent Claim
24 words
The projection lens apparatus of claim 1 , further comprising an aperture stop adapted to pass the image light and whose position is accessible.
Claim 19
Dependent Claim
23 words
The projection lens apparatus of claim 17 , wherein the aperture stop is adapted to receive a filter for filtering the image light.
Claim 20
Dependent Claim
17 words
The projection lens apparatus of claim 1 , wherein the chromatic separating element comprises a Philips prism.
Claim 21
Dependent Claim
18 words
The projection lens apparatus of claim 1 , wherein the chromatic separating element comprises an X cube prism.
Claim 22
Dependent Claim
18 words
The projection lens apparatus of claim 1 , wherein the field lens comprises a weak, negatively powered lens.
Claim 23
Dependent Claim
25 words
The projection lens apparatus of claim 1 , wherein the chromatic separating element is adapted to recombine the color separated light it had previously separated.
Claim 24
Dependent Claim
27 words
The projection lens apparatus of claim 1 , wherein the chromatic separating element is adapted to separate the illumination light that is substantially telecentric at the imager.
Claim 25
Dependent Claim
37 words
The projection lens apparatus of claim 1 , wherein the back lens unit and the linearly reflecting polarizer are adapted to direct the illumination light substantially in a first polarization that is substantially telecentric at the imager.
Claim 26
Dependent Claim
23 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises an aspheric surface adapted to pass the image light.
Claim 27
Dependent Claim
18 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises overall negative optical power.
Claim 28
Dependent Claim
17 words
The projection lens apparatus of claim 1 , wherein the back lens unit comprises overall positive power.
Claim 29
Dependent Claim
22 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises two aspheres adapted to pass the image light.
Claim 30
Dependent Claim
28 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises a compound lens element having a clean-up element adapted to clean-up the image light.
Claim 31
Dependent Claim
21 words
The projection lens apparatus of claim 29 , wherein the clean-up element comprises a filter adapted to filter the image light.
Claim 32
Dependent Claim
16 words
The projection lens apparatus of claim 29 , wherein the clean-up element comprises a polarizing filter.
Claim 33
Dependent Claim
28 words
The projection lens apparatus of claim 1 , wherein the front lens unit is adapted to pass the image light substantially in one polarization to a projection screen.
Claim 34
Dependent Claim
24 words
The projection lens apparatus of claim 1 , wherein an aperture stop is disposed between the linear reflecting polarizer and the first lens unit.
Claim 35
Dependent Claim
17 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises an aspheric surface.
Claim 36
Dependent Claim
18 words
The projection lens apparatus of claim 1 , wherein the front lens unit comprises at least one asphere.
Claim 37
Dependent Claim
26 words
The projection apparatus of claim 1 , wherein an entrance pupil of the projection lens is adapted to match an exit pupil of a light source.
Claim 38
Dependent Claim
18 words
The image projection lens system of claim 25 , wherein the projection lens comprises a remote aperture stop.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-27 | 2005-02-26 | 2005-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-27 | 2009-02-26 | 2009-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-27 | 2013-02-26 | 2013-08-28 | $7700.00 | Window Closed / Lapsed |