EP0443586A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Projector
Assignee: Canon Inc
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Filing: 1991-02-21
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Granted: —
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Expires: 2011-02-21
Abstract
Abstract There is provided a projector comprising: a radiation source; an illuminating system having an arrangement of the first and second polarizing beam splitters and a phase plate, in which dividing surfaces of both of the polarizing beam splitters are parallel with each other, the phase plate is arranged between both of the dividing surfaces, the first polarizing beam splitter reflects an S polarizing component in a white beam from the radiation source and transmits a P polarizing component and leads to the phase plate, and the second polarizing beam splitter reflects another S polarizing component which occurred by the phase plate; a cross dichroic mirror system which receives the beam from the arrangement; a first optical modulator for modulating a polarizing plane of the red component of the beam from the mirror system, for reflecting the red component, and for generating a first beam indicative of a first image; a second optical modulator for modulating a polarizing plane of a green component of the beam from the mirror system, for reflecting the green component, and for generating a second beam indicative of a second image; a third optical modulator for modulating a polarizing plane of a blue component of the beam from the mirror system, for reflecting the blue component, and for generating a third beam indicative of a third image; and a projection optical system for receiving the first to third beams through the mirror system and both of the dividing surfaces of the arrangement and for projecting a color image in which the first to third images were overlaid by those beams.
Inventors
- 👤 Katsumi Kurematsu
- 👤 Hideaki Mitsutake
- 👤 Nobuo Minoura
- 👤 Haruyuki Yanagi
- 👤 Masaaki Kanashiki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 01:48
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3141; H04N9/315; H04N9/3167
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
260 words
A projector comprising: a radiation source; an illuminating system having an arrangement of first and second polarizing beam splitters and a phase plate, in which dividing surfaces of both of said polarizing beam splitters are parallel with each other, the phase plate is arranged between both of said dividing surfaces, the first polarizing beam splitter reflects an S polarizing component in a white beam emitted from said radiation source and transmits a P polarizing component and leads to the phase plate, and the second polarizing beam splitter reflects another S polarizing component which occurred by the phase plate; a dichroic mirror system which receives the beam from said arrangement; a first optical modulator for modulating a polarizing plane of a red component of the beam from the mirror system, for reflecting said red component, and for generating a first beam indicative of a first image; a second optical modulator for modulating a polarizing plane of a green component of the beam from the mirror system, for reflecting said green component, and for generating a second beam indicative of a second image; a third optical modulator for modulating a polarizing plane of a blue component of the beam from the mirror system, for reflecting said blue component, and for generating a third beam indicative of a third image; and a projection optical system for receiving said first to third beams through the mirror system and both of the dividing surfaces of said arrangement and for projecting a color image in which said first to third images were overlaid by said beams.
Claim 2
Dependent Claim
15 words
A projector according to claim 1, wherein the phase plate has a half wavelength film.
Claim 3
Dependent Claim
18 words
A projector according to claim 1, wherein the phase plate has a 90° twisted nematic liquid crystal layer.
Claim 4
Dependent Claim
31 words
A projector according to claim 1, wherein the first to third optical modulators have liquid crystal layers for rotating the polarizing planes of the beams in accordance with the video signal.
Claim 5
Dependent Claim
23 words
A projector according to claim 1, wherein the phase plate is arranged close to the dividing surface of the first polarizing beam splitter.
Claim 6
Dependent Claim
34 words
A projector according to claim 1, wherein each of the first and second polarizing beam splitters has a cube-like outer shape and the phase plate is sandwiched by both of said polarizing beam splitters.
Claim 7
Dependent Claim
20 words
A projector according to any one of claims 1 to 6, wherein the dichroic mirror system comprises cross dichroic mirrors.
Claim 8
Dependent Claim
282 words
A projector comprising: a radiation source; an illuminating system having an arrangement of first, second, and third polarizing beam splitters and a phase plate, in which dividing surfaces of the first and second polarizing beam splitters are parallel with each other, the phase plate is arranged between both of said dividing surfaces, the first polarizing beam splitter reflects an S polarizing component in a white beam emitted from the radiation source and leads to the third polarizing beam splitter and transmits a P polarizing component and leads to the phase plate, and the second polarizing beam splitter reflects another S polarizing component which occurred by the phase plate and leads to the third polarizing beam splitter; a dichroic mirror system which receives the beam from the third polarizing beam splitter; a first optical modulator for modulating a polarizing plane of a red component of the beam from the mirror system, for reflecting said red component, and for generating a first beam indicative of a first image; a second optical modulator for modulating a polarizing plane of a green component of the beam from the mirror system, for reflecting said green component, and for generating a second beam indicative of a second image; a third optical modulator for modulating a polarizing plane of a blue component of the beam from the mirror system, for reflecting said blue component, and for generating a third beam indicative of a third image; and a projection optical system for receiving the first to third beams through the mirror system and the dividing surface of the third polarizing beam splitter and for projecting a color image in which the first to third images were overlaid by said beams.
Claim 9
Dependent Claim
15 words
A projector according to claim 8, wherein the phase plate has a half wavelength film.
Claim 10
Dependent Claim
18 words
A projector according to claim 8, wherein the phase plate has a 90° twisted nematic liquid crystal layer.
Claim 11
Dependent Claim
31 words
A projector according to claim 8, wherein the first to third optical modulators have liquid crystal layers for rotating the polarizing planes of the beams in accordance with the video signal.
Claim 12
Dependent Claim
23 words
A projector according to claim 8, wherein the phase plate is arranged close to the dividing surface of the first polarizing beam splitter.
Claim 13
Dependent Claim
34 words
A projector according to claim 8, wherein each of the first and second polarizing beam splitters has a cube-like outer shape and the phase plate is sandwiched by both of said polarizing beam splitters.
Claim 14
Dependent Claim
33 words
A projector according to claim 8, wherein the illuminating system has a bending mirror and both of the S polarizing components are led to the third polarizing beam splitter by said bending mirror.
Claim 15
Dependent Claim
20 words
A projector according to any one of claims 8 to 14, wherein the dichroic mirror system comprises cross dichroic mirrors.
Claim 16
Dependent Claim
136 words
An optical modulation system comprising: a radiation source; modulator for modulating a polarizing plane of a polarizing beam which enters the modulator and reflecting said polarizing beam, thereby generating a reflection beam; and an optical arrangement having a first polarizing beam splitter for dividing the beam from the radiation source to both of P and S polarizing components and leading the S polarizing component to the modulating means, a converter for rotating a polarizing plane of the P polarizing component and converting into another S polarizing component, and a second polarizing beam splitter for reflecting said another S polarizing component and leading to the modulator, wherein said polarizing beam is generated by both of said S polarizing components and said first and second polarizing beam splitters are made act as an analyzer of the reflection beam.
Claim 17
Dependent Claim
28 words
A system according to claim 16, further having a projection optical system for leading the reflection beam in a predetermined direction through each of the polarizing beam splitters.
Claim 18
Dependent Claim
30 words
A system according to claim 17, wherein the modulator executes the modulation in accordance with a video signal and a projection optical system projects an image by the reflection beam.
Claim 19
Dependent Claim
28 words
A system according to claim 16, wherein the optical arrangement has an optical system for leading the beam from the radiation source to the first polarizing beam splitter.
Claim 20
Dependent Claim
17 words
A system according to claim 16, wherein the polarizing beam splitters and the converter are integratedly arranged.
Claim 21
Dependent Claim
285 words
A projector comprising: a radiation source; an illuminating system having an arrangement of the first polarizing beam splitter and a reflecting surface, a phase plate, and a second polarizing beam splitter, in which a dividing surface and the reflecting surface of the first polarizing beam splitter are parallel with each other, the first polarizing beam splitter reflects an S polarizing component of a white beam from the radiation source and leads to the second polarizing beam splitter and transmits a P polarizing component and leads to the reflecting surface, the reflecting surface reflects the P polarizing component and leads to the second polarizing beam splitter, and the phase plate makes polarizing directions of both of the polarizing components coincide; a dichroic mirror system which receives the beam from the second polarizing beam splitter; a first optical modulator for modulating a polarizing plane of a red component of the beam from the mirror system, for reflecting said red component, and for generating a first beam indicative of a first image; a second optical modulator for modulating a polarizing plane of a green component of the beam from the mirror system, for reflecting said green component, and for generating a second beam indicative of a second image; a third optical modulator for modulating a polarizing plane of a blue component of the beam from the mirror system, for reflecting said blue component, and for generating a third beam indicative of a third image; and a projection optical system for receiving said first to third beams through the mirror system and a dividing surface of the second polarizing beam splitter and for projecting a color image in which the first to third images were overlaid by said beams.
Claim 22
Dependent Claim
15 words
A projector according to claim 21, wherein the phase plate has a half wavelength film.
Claim 23
Dependent Claim
18 words
A projector according to claim 21, wherein the phase plate has a 90° twisted nematic liquid crystal layer.
Claim 24
Dependent Claim
48 words
A projector according to claim 21, wherein the phase plate is arranged on a path of the S polarizing component from the first polarizing beam splitter and converts the S polarizing component into another P polarizing component, thereby making polarizing directions of both of said polarizing components coincide.
Claim 25
Dependent Claim
49 words
A projector according to claim 24, wherein the illuminating system has a bending mirror, and by reflecting the P polarizing component and said another P polarizing component by said bending mirror, both of said polarizing components are led to the second polarizing beam splitter as an S polarizing beam.
Claim 26
Dependent Claim
47 words
A projector according to claim 21, wherein the phase plate is arranged on a path of the P polarizing component from the first polarizing beam splitter, and by converting the P polarizing component into another S polarizing component, polarizing directions of both of said polarizing components coincide.
Claim 27
Dependent Claim
31 words
A projector according to claim 21, wherein the first to third optical modulators have liquid crystal layers for rotating the polarizing planes of the beams in accordance with a video signal.
Claim 28
Dependent Claim
20 words
A projector according to any one of claims 21 to 27, wherein the dichroic mirror system comprises cross dichroic mirrors.
References Cited (Backward Citations)
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