US6233024B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rear projector
Assignee: LDT Laser Display Technology GmbH
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Filing: 1998-08-26
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Granted: 2001-05-15
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Expires: 2018-08-26
Abstract
Abstract In a rear projector with a housing on whose front side is arranged a screen for displaying a video picture, with a brightness-modulated and color-modulated R-G-B light source for emitting a light bundle, with a deflecting device for scanning this light bundle, wherein the light bundle is deflected by the deflecting device over a total angle alpha with respect to vertical scanning, and with a deflecting mirror which is located in the housing and arranged at an angle delta, wherein the light bundle exiting from a real or virtual vertex of the total deflection angle alpha is deflected onto the screen by the deflecting mirror, the virtual or real vertex located in front of the deflecting mirror lies at a location where the smallest angle beta of the light bundle to the surface of the screen during deflection is less than 20° and the angle delta is given by
Inventors
- 👤 Klaus Hiller
- 👤 Frank Goepfert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:19
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3129
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
202 words
A rear projector comprising: a housing; a screen arrangement on a front side of the housing for displaying a video picture; a brightness-modulated and color-modulated R-G-B light source for emitting a light bundle; a deflecting device for scanning said light bundle; said deflecting device for deflecting said light bundle over a total angle α with respect to vertical scanning; a deflecting mirror which is located in the housing and arranged at an angle δ; wherein the light bundle exiting from a real or virtual vertex of the total deflection angle α is deflected onto the screen by the deflecting mirror; wherein the virtual or real vertex located in front of the deflecting mirror lies at a location where the smallest angle β of the light bundle to the surface of the screen during deflection is less than 20° and the angle δ is given by δ ≤ 45 ° - α 4 + β ; and wherein angle δ is determined for curved mirror surfaces of the deflecting mirror between the projection surface given by the screen and the chord between the extreme points of incidence of the light bundle on the deflecting mirror during vertical scanning over the angle α.
Claim 2
Dependent Claim
202 words
A rear projector comprising: a housing; a screen arrangement on a front side of the housing for displaying a video picture; a brightness-modulated and color-modulated R-G-B light source for emitting a light bundle; a deflecting device for scanning said light bundle; said deflecting device for deflecting said light bundle over a total angle α with respect to vertical scanning; a deflecting mirror which is located in the housing and arranged at an angle δ; wherein the light bundle exiting from a real or virtual vertex of the total deflection angle α is deflected onto the screen by the deflecting mirror; wherein the virtual or real vertex located in front of the deflecting mirror lies at a location where the smallest angle β of the light bundle to the surface of the screen during deflection is less than 20° and the angle δ is given by δ ≤ 45 ° - α 4 + β ; and wherein angle δ is determined for curved mirror surfaces of the deflecting mirror between the projection surface given by the screen and the chord between the extreme points of incidence of the light bundle on the deflecting mirror during vertical scanning over the angle α.
Claim 3
Dependent Claim
24 words
The rear projector according to claim 1 , wherein the vertex is virtual and is generated by additional deflecting mirrors in the rear projector.
Claim 4
Dependent Claim
89 words
The rear projector according to claim 1 , wherein a computing device by which the video picture is recalculated prior to projection with respect to distortion due to oblique projection or curvature of the deflecting mirror and by a control device which controls the deflection and/or intensity modulation of the light bundle, so that there appears on the screen in the image direction a virtually undistorted video picture which diverges from an equal distribution of lines by less than 30%, particularly less than 10%, with respect to line spacing.
Claim 5
Dependent Claim
43 words
The rear projector according to claim 1 , wherein the distance of the screen from the point on the deflecting mirror on which the light bundle impinges at an angle β is less than 10 cm and, in particular, less than 3 cm.
Claim 6
Dependent Claim
38 words
The rear projector according to claim 1 , wherein the deflecting mirror is a plane mirror and a light bundle reflected at a deflection angle α/2 in the direction of the deflecting mirror impinges vertically on the screen.
Claim 7
Dependent Claim
21 words
The rear projector according to claim 1 , wherein the R-G-B light source is arranged on the base of the housing.
Claim 8
Dependent Claim
20 words
The rear projector according to claim 1 , wherein the deflecting device is arranged at the base of the housing.
Claim 9
Dependent Claim
33 words
The rear projector according to claim 1 , wherein the deflecting device has magnification optics that have been corrected for the tangential condition for proportional magnification of the tangent of the deflection angle.
References Cited (Backward Citations)
US4030821A
Cited
US4136935A
Cited
US4439027A
Cited
US5223869A
Cited
US5546200A
Cited
US5897192A
Cited
US5796446A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-14 | 2012-11-13 | 2013-05-15 | $7700.00 | Window Closed / Lapsed |