Patent US5333072A successfully refreshed from Google Patents.
US5333072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reflective liquid crystal display overhead projection system using a reflective linear polarizer and a fresnel lens
Assignee: 3M Co
•
Filing: 1992-12-31
•
Granted: 1994-07-26
•
Expires: 2012-12-31
Abstract
Abstract A reflective liquid crystal display overhead projection system. The projection system includes a reflective polarizer, a phase modulating liquid crystal display on the reflective polarizer, and a fresnel lens on the liquid crystal display. Unpolarized light rays are directed toward the fresnel lens, pass through the liquid crystal display, and are reflected and polarized by the reflective polarizer. The light rays then pass back through the liquid crystal display and the fresnel lens and on toward a projector head, where the light rays are analyzed by a polarizer and projected toward a screen.
Inventors
- 👤 Stephen J. Willett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:33
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/74; H04N5/7416; H04N5/7441; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133528; G02F1/133536; G03; G03B; G03B21/00; G03B21/132
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
91 words
An optical stack for use in a reflective liquid crystal display projection system comprising a reflective micro-prism array MacNeille polarizer, a phase modulating liquid crystal display provided on the polarizer, and a transmissive fresnel lens provided on the liquid crystal display, wherein unpolarized light rays directed toward the fresnel lens pass through the fresnel lens and the liquid crystal display, are then reflected and polarized by the polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, and pass back through the fresnel lens.
Claim 2
Dependent Claim
91 words
An optical stack for use in a reflective liquid crystal display projection system comprising a reflective micro-prism array MacNeille polarizer, a phase modulating liquid crystal display provided on the polarizer, and a transmissive fresnel lens provided on the liquid crystal display, wherein unpolarized light rays directed toward the fresnel lens pass through the fresnel lens and the liquid crystal display, are then reflected and polarized by the polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, and pass back through the fresnel lens.
Claim 3
Dependent Claim
157 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective micro-prism array MacNeille polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 4
Dependent Claim
157 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective micro-prism array MacNeille polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 5
Dependent Claim
164 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer comprised of a circular polarizer and a quarter-wave retarding plate; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 6
Dependent Claim
164 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer comprised of a circular polarizer and a quarter-wave retarding plate; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 7
Dependent Claim
168 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer comprised of one of a micro-prism array MacNeille polarizer and a birefringent interference polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 8
Dependent Claim
168 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer comprised of one of a micro-prism array MacNeille polarizer and a birefringent interference polarizer; and a projector head, wherein the second linear polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 9
Dependent Claim
163 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer comprised of a circular polarizer and a quarter-wave retarding plate; and a projector head, wherein the second polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 10
Dependent Claim
163 words
A reflective liquid crystal display overhead projection system, comprising: a first linear polarizer which is a reflective polarizer; a phase modulating liquid crystal display provided on the first linear polarizer; a transmissive fresnel lens provided on the liquid crystal display; a second linear polarizer comprised of a circular polarizer and a quarter-wave retarding plate; and a projector head, wherein the second polarizer is attached to the projector head, and wherein the projector head comprises a projector lamp and a projection lens, wherein unpolarized light rays from the lamp are directed toward the fresnel lens, pass through the fresnel lens and the liquid crystal display, are reflected and polarized by the first linear polarizer, pass back through the liquid crystal display where the phase of the light rays is modulated, pass back through the fresnel lens, and are directed toward and pass through the second linear polarizer and projection lens, whereby an image displayed by the liquid crystal display is projected onto a screen.
Claim 11
Independent Claim
142 words
A method of projecting an image displayed by a liquid crystal display onto a screen, comprising: directing unpolarized light rays toward an optical stack, wherein the optical stack includes a first linear polarizer which is a reflective micro-prism array MacNeille polarizer, a phase modulating liquid crystal display provided on the reflective polarizer, and a transmissive fresnel lens provided on the liquid crystal display, wherein the unpolarized light rays pass through the fresnel lens and the liquid crystal display; reflecting and polarizing the light rays by the use of the first polarizer, wherein the reflected, polarized light rays pass back through the liquid crystal display and the fresnel lens, and then travel toward a projector head; analyzing the reflected, polarized light rays with a second linear polarizer attached to the projection head; and projecting the reflected, polarized light rays onto a projection screen.
Claim 12
Independent Claim
142 words
A method of projecting an image displayed by a liquid crystal display onto a screen, comprising: directing unpolarized light rays toward an optical stack, wherein the optical stack includes a first linear polarizer which is a reflective micro-prism array MacNeille polarizer, a phase modulating liquid crystal display provided on the reflective polarizer, and a transmissive fresnel lens provided on the liquid crystal display, wherein the unpolarized light rays pass through the fresnel lens and the liquid crystal display; reflecting and polarizing the light rays by the use of the first polarizer, wherein the reflected, polarized light rays pass back through the liquid crystal display and the fresnel lens, and then travel toward a projector head; analyzing the reflected, polarized light rays with a second linear polarizer attached to the projection head; and projecting the reflected, polarized light rays onto a projection screen.
References Cited (Backward Citations)
US3844650A
Cited
US4525413A
Cited
US4613207A
Cited
JPS62245215A
Cited
US4818074A
Cited
WO1988002501A1
Cited
US4763993A
Cited
EP0295913B1
Cited
JPH02193183A
Cited
EP0488544A1
Cited
US5206673A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-07-25 | 1998-01-24 | 1998-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-25 | 2002-01-24 | 2002-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-25 | 2006-01-24 | 2006-07-26 | $7700.00 | Window Closed / Lapsed |