Patent EP0389240A2 successfully refreshed from Google Patents.
EP0389240A2
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EP
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Polarizing beam splitter apparatus and light valve image projection system
Assignee: Panasonic Holdings Corp
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Filing: 1990-03-20
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Granted: —
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Expires: 2010-03-20
Abstract
Abstract Disclosed are a polarizing beam splitter apparatus having a polarizing beam splitter (22) commonly usable as a polarizer and an analyzer, and a quarter wave plate (25) in combination; and a light valve image projection system using the same. In the polarizing beam splitter apparatus, a quarter wave plate (25) is arranged in a light path along which a light goes out from and goes back again to the polarizing beam splitter (22) in such a manner that either a fast optic axis (28) or a slow optic axis (29) of the quarter wave plate (25) is perpendicular to a plane containing an incident optical axis (30) and an reflection optical axis (31) of the polarizing beam (22) splitter, so that the angular range of a light to be used can be increased. In the light valve image projection system, a light outputted from a light source (21) is incident through a polarizing beam splitter apparatus to a light valve, and an effective component of the light reflected from the light valve (26) is projected through the polarizing beam splitter apparatus and a projection lens (27) on a projection screen. The polarizing beam splitter apparatus of this invention is high in polarization efficiency even if the range of incident angle of a light to be used is large, so that a projected image highly improved in contrast and brightness can be obtained.
Inventors
- 👤 Yoshito Miyatake
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:08
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/28; G02B27/283; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/1396; G02F1/1398; G02F2203/00; G02F2203/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
90 words
A polarizing beam splitter apparatus comprising: a polarizing beam splitter commonly usable as a polarizer and an analyzer; and a quarter wave plate; wherein said quarter wave plate is arranged in a light path along which a light goes out from and goes back again to said polarizing beam splitter in such a manner that either a fast optic axis or a slow optic axis of said quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optical axis of said polarizing beam splitter.
Claim 2
Dependent Claim
90 words
A polarizing beam splitter apparatus comprising: a polarizing beam splitter commonly usable as a polarizer and an analyzer; and a quarter wave plate; wherein said quarter wave plate is arranged in a light path along which a light goes out from and goes back again to said polarizing beam splitter in such a manner that either a fast optic axis or a slow optic axis of said quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optical axis of said polarizing beam splitter.
Claim 3
Dependent Claim
23 words
A polarizing beam splitter apparatus as claimed in claim 1, wherein said quarter wave plate is securedly adhered to said polarizing beam splitter.
Claim 4
Dependent Claim
55 words
A polarizing beam splitter apparatus as claimed in claim 1, wherein a polarizing plate is arranged in an incident light path of said polarizing beam splitter as a polarizer and/or an outgoing light path of the same as an analyzer so as to pass a linearly polarized light having a predetermined direction of polarization therethrough.
Claim 5
Dependent Claim
54 words
A polarizing beam splitter apparatus as claimed in claim 1, wherein a polarizing plate is securedly adhered onto an incident surface of said polarizing beam splitter as a polarizer and/or an outgoing surface of the same as an analyzer so as to pass a linearly polarized light having a predetermined direction of polarization therethrough.
Claim 6
Dependent Claim
149 words
A light valve image projection system comprising: a light source; a polarizing beam splitter; a reflection light valve for modulating a polarization state of a light and reflecting the light thus modulated; a quarter wave plate; and a projection lens; wherein an output light from said light source is incident through said polarizing beam splitter to said light valve and an effective component contained into the light reflected from said light valve is projected through said polarizing beam splitter and said projection lens on a projection screen, and wherein said quarter wave plate is arranged in a light path between said polarizing beam splitter and said light valve in such a manner that either a fast optic axis or a slow optic axis of the said quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optical axis of said polarizing beam splitter.
Claim 7
Dependent Claim
149 words
A light valve image projection system comprising: a light source; a polarizing beam splitter; a reflection light valve for modulating a polarization state of a light and reflecting the light thus modulated; a quarter wave plate; and a projection lens; wherein an output light from said light source is incident through said polarizing beam splitter to said light valve and an effective component contained into the light reflected from said light valve is projected through said polarizing beam splitter and said projection lens on a projection screen, and wherein said quarter wave plate is arranged in a light path between said polarizing beam splitter and said light valve in such a manner that either a fast optic axis or a slow optic axis of the said quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optical axis of said polarizing beam splitter.
Claim 8
Dependent Claim
27 words
A light valve image projection system as claimed in claim 5, wherein said polarizing beam splitter and said quarter wave plate are securedly adhered with each other.
Claim 9
Dependent Claim
56 words
A light valve image projection system as claimed in claim 5, wherein a polarizing plate is arranged in an incident light path of said polarizing beam splitter as a polarizer and/or an outgoing light path of the same as an analyzer so as to pass a linearly polarized light having a pre-determined direction of polarization therethrough.
Claim 10
Dependent Claim
55 words
A light valve image projection system as claimed in claim 5, wherein a polarizing plate is securedly adhered onto an incident surface of said polarizing beam splitter as a polarizer and/or an outgoing surface of the same as an analyzer so as to pass a linearly polarized light having a pre-determined direction of polarization therethrough.
Claim 11
Dependent Claim
20 words
A light valve image projection system as claimed in claim 5, wherein said light source comprises a metal halide lamp.
Claim 12
Dependent Claim
219 words
A light valve image projection system comprising: a light source containing color components of three primary colors; a color separation means for separating an output light from said light source into lights of the three primary colors; three polarizing beam splitters; three reflection light valves each for modulating a polarization state of a light and reflecting the light thus modulated; three quarter wave plates; and three projection lenses; wherein each color light from said color separation means is incident through a corresponding one of said three polarizing beam splitters to a corresponding one of said three reflection light valves and an effective component contained in a light reflected from each of said three light valves is projected through a corresponding one of said three polarizing beam splitters and a corresponding one of said three projection lenses on a projection screen, and wherein each of said three quarter wave plates is arranged in a light path between a corresponding one of said three polarizing beam splitters and a corresponding one of said three light valves in such a manner that either a fast optic axis or a slow optic axis of each quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optic axis of a corresponding one of said three polarizing beam splitters.
Claim 13
Dependent Claim
219 words
A light valve image projection system comprising: a light source containing color components of three primary colors; a color separation means for separating an output light from said light source into lights of the three primary colors; three polarizing beam splitters; three reflection light valves each for modulating a polarization state of a light and reflecting the light thus modulated; three quarter wave plates; and three projection lenses; wherein each color light from said color separation means is incident through a corresponding one of said three polarizing beam splitters to a corresponding one of said three reflection light valves and an effective component contained in a light reflected from each of said three light valves is projected through a corresponding one of said three polarizing beam splitters and a corresponding one of said three projection lenses on a projection screen, and wherein each of said three quarter wave plates is arranged in a light path between a corresponding one of said three polarizing beam splitters and a corresponding one of said three light valves in such a manner that either a fast optic axis or a slow optic axis of each quarter wave plate is perpendicular to a plane containing an incident optical axis and a reflection optic axis of a corresponding one of said three polarizing beam splitters.
Claim 14
Dependent Claim
27 words
A light valve image projection system as claimed in claim 10, wherein said three polarizing beam splitters are securedly adhered correspondingly to said three quarter wave plates.
Claim 15
Dependent Claim
56 words
A light valve image projection system as claimed in claim 10, wherein a polarizing plate is arranged in an incident light path of each polarizing beam splitter as a polarizer and/or an outgoing light path of the same as an analyzer so as to pass a linearly polarized light having a pre-determined direction of polarization therethrough.
Claim 16
Dependent Claim
55 words
A light valve image projection system as claimed in claim 10, wherein a polarizing plate is securedly adhered onto an incident surface of each polarizing beam splitter as a polarizer and/or an outgoing surface of the same as an analyzer so as to pass a linearly polarized light having a pre-determined direction of polarization therethrough.
Claim 17
Dependent Claim
20 words
A light valve image projection system as claimed in claim 10, wherein said light source comprises a metal halide lamp.
References Cited (Backward Citations)
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