US5028121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Projection device
Assignee: Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV
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Filing: 1988-06-11
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Granted: 1991-07-02
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Expires: 2008-06-11
Abstract
Abstract A projector has a light source (1) for producing a parallel beam of white light (4); two dichroic prisms (21, 22) each having two dichroic colour-splitting layers, which on three of their sides have three liquid crystal light valve arrangements (23, 24, 25, 26, 27, 28) associated with different components of the color image; a lens (8) through which the color image components produced by the light valve arrangements (23 to 28) can be projected together on to a screen. The light valve arrangements (23 to 28) associated with the two dichroic prisms operate by reflection. Each of the two dichroic prisms (21, 22) is coupled with one of the outlets of a polarizing beam splitter (10), said outlets being associated with different polarizing directions. The polarizing beam splitter (10) distributes the beam of white light (4, 6) to the two dichroic prisms (21, 22) and directs the light of the activated image points travelling back from the two dichroic prisms into the lens (8).
Inventors
- 👤 Gunter Baur
- 👤 Lutz Pickelmann
- 👤 Jorg Seibel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:19
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3141; H04N9/315; H04N9/3167; G; G02; G02B; G02B27/00; G02B27/28; G02B27/283
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
A projection device comprising: light generating means for generating a white parallel light beam bundle; a polarizing beam divider having at least two outputs allocated to different polarization directions; at least two dichroic prisms respectively coupled to said outputs, each said dichroic prism including two dichroic color divider layers and three reflectively operating liquid crystal light valve arrangements allocated to three different color image separations, each said light valve arrangement having a matrix of driven image lines for forming a plurality of activatable image points for selectively reflecting color image separated light; and an objective through which the reflected color image separated light from the activated image point is projected.
Claim 2
Dependent Claim
110 words
A projection device comprising: light generating means for generating a white parallel light beam bundle; a polarizing beam divider having at least two outputs allocated to different polarization directions; at least two dichroic prisms respectively coupled to said outputs, each said dichroic prism including two dichroic color divider layers and three reflectively operating liquid crystal light valve arrangements allocated to three different color image separations, each said light valve arrangement having a matrix of driven image lines for forming a plurality of activatable image points for selectively reflecting color image separated light; and an objective through which the reflected color image separated light from the activated image point is projected.
Claim 3
Dependent Claim
13 words
Device according to claim 1, wherein said beam divider is a McNeille prism.
Claim 4
Dependent Claim
22 words
Device according to claim 2, characterized in that the beam divider is housed in a cuvette filled with a highly refractive liquid.
Claim 5
Dependent Claim
23 words
Device according to claim 1, wherein said light valve arrangements have a reflecting layer on the side facing away from the dichroic prisms.
Claim 6
Dependent Claim
19 words
Device according to claim 1, wherein color filters are provided between said light valve arrangements and said dichroic prisms.
Claim 7
Dependent Claim
34 words
Device according to claim 1, wherein said two dichroic prisms are tilted to one another by 90 degrees and are coupled with sides of said beam divider oriented to one another by 90 degrees.
Claim 8
Dependent Claim
20 words
Device according to claim 1, wherein said beam divider is housed in a cuvette filled with a highly refractive liquid.
Claim 9
Dependent Claim
48 words
Device according to claim 1, wherein said beam divider includes a beam divider plate which extends along a diagonal in a cuvette that is filled with a highly refractive liquid and in which on both sides of the beam divider plate there are provided highly refractive wedge prisms.
Claim 10
Dependent Claim
21 words
Device according to claim 1, wherein said projections of the image lines of all six light valve arrangements cover one another.
Claim 11
Dependent Claim
43 words
Device according to claim 1, wherein the projections of the driven image lines of the light valve arrangement of a first said dichroic prism lie between the projections of the image lines of the light valves allocated to a second said dichroic prism.
Claim 12
Dependent Claim
41 words
Device according to claim 10, wherein the light valves allocated to said first dichroic prism and the light valves allocated to said second dichroic prism present a second partial image of a three-dimensional image with driven lines of different polarization direction.
Claim 13
Dependent Claim
41 words
Device according to claim 1, wherein the projections of the driven image lines of the light valves of a first said dichroic prism lie on the projections of the image lines of the light valves of a second said dichroic prism.
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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) | 1994-07-01 | 1994-12-31 | 1995-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-01 | 1998-12-31 | 1999-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-01 | 2002-12-31 | 2003-07-02 | $7700.00 | Window Closed / Lapsed |