EP0602732A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical system with astigmatism compensation
Assignee: Koninklijke Philips NV
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Filing: 1993-12-10
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Granted: —
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Expires: 2013-12-10
Abstract
Abstract The present invention is directed to compensation plates (2) for eliminating astigmatism and coma optical aberration in optical systems. In particular, the present invention can be used in LCD projection systems to compensate for aberrations in different colour channels (6-1, 5-1, 4-1). This enables the production of LCD systems completely free of astigmatism and/or coma.
Inventors
- 👤 Jeffrey Shimizu
- 👤 Peter Janssen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:54
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/10; G02B27/14; G02B27/145; G02B27/0025; H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/3105
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
73 words
An optical system for guiding a radiation beam and comprising an optical plate shaped element which is tilted with respect to the axis of said beam and a compensating plate being tilted with respect to the beam axis at the same angle as the optical element, characterized in that the compensating plate is rotated 90° about the beam axis with respect to the optical element to completely eliminate astigmatism introduced by said element.
Claim 2
Dependent Claim
49 words
An optical system as claimed in claim 1, characterized in that a second compensating plate is disposed in the path of said beam which plate is rotated 180° about said beam axis with respect to the first compensating plate to also eliminate coma aberration introduced by said optical element.
Claim 3
Dependent Claim
115 words
A colour image projection device comprising a light source providing a light beam, beam splitting means for splitting the light beam into a read, a green and a blue subbeam, light valve means disposed in the paths of said subbeams for modulating the red, green and blue subbeams, means for combining the modulated red, green and blue subbeams into a projection beam, a projection lens for projecting the projection beam onto a projection screen and at least one optical system as claimed in claim 1 or 2 disposed in the path of one of said subbeams, wherein said optical plate shaped element is a colour filter forming part of said beam splitting or combining means.
Claim 4
Dependent Claim
87 words
A colour image projection device as claimed in claim 3, wherein said at least one optical system comprises a second compensating plate, characterized in that a third compensating plate is disposed in the path of said subbeam which plate is rotated 90° with respect to said second plate and in that the second and third compensating plates are rotated 180° with respect to said optical element and the first compensating plate, the combination of the first, second and third compensating plates eliminate both astigmatism and coma aberrations.
Claim 5
Dependent Claim
17 words
A colour light valve system according to claim 5 wherein said light valve means are LCD panels.
References Cited (Backward Citations)
No citation records indexed.
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