US5570209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color projection type display apparatus having three liquid crystal displays of same structure
Assignee: Mitsubishi Electric Corp
•
Filing: 1994-02-28
•
Granted: 1996-10-29
•
Expires: 2014-02-28
Abstract
Abstract The present invention provides a color projector utilizing three liquid crystal display elements. The natural light is separated into illuminating rays of red, green and blue colors by a dichroic mirror, each of these illuminating rays being used to illuminate the corresponding one of the liquid crystal display elements. Each of the liquid crystal display elements is controlled by a desired image signal with respect to its transmittance at each pixel. After passed through the liquid crystal display elements, three kinds of colored illuminating rays are again synthesized by the other dichroic mirror to form a light beam which in turn is enlarged and projected by a projecting lens on a screen. By providing light source means including means for converting the natural light into the linearly polarized beam, the illuminating rays may have their polarizing angles coincide with each other without any loss of light. As the linearly polarized beam is reflected by the mirror system, the illuminating rays of red, green and blue colors are changed with respect to their polarizing angels. Depending on the changed polarizing angles, the polarizing angle of the light rays incident on each of the liquid crystal display elements may be adjusted to remove any loss of light.
Inventors
- 👤 Masahiro Usui
- 👤 Hiroshi Kida
- 👤 Shinsuke Shikama
- 👤 Mitsushige Kondo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:33
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/3105; G; G02; G02B; G02B27/00; G02B27/28; G02B27/283; H04N9/3141; H04N9/315; H04N9/3167
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
257 words
A projection type display apparatus having three rectangular liquid crystal display elements each of which has an entrance side polarizing plate with the same polarizing direction, which is parallel to one side of the respective rectangular liquid crystal display element comprising: a light source producing non-polarized illuminating light; converting means, receiving the non-polarized illuminating light and converting the non-polarized illuminating light to illuminating light having a direction of polarization parallel to one side of the three rectangular liquid crystal display elements including, polarized light separating means for separating the non-polarized illuminating light into two linearly polarized light beams, polarization direction rotating means for rotating the polarization direction of at least one of the two polarized light beams to make the polarization direction of the two light beams identical, and synthesizing means for synthesizing the two polarized light beams so that the optical axes of said two polarized light beams are non-parallel to each other, spectroscope means for separating said linearly polarized light beam into light rays of red, green and blue colors; wherein the three rectangular liquid crystal display elements each permit the respective light rays of red, green and blue colors to pass therethrough, the transmittance of each pixel being controlled by a desired image signal, each of the three rectangular liquid crystal display elements being composed of a pair of polarizing plates and a liquid crystal layer being held therebetween; a light synthesizer for synthesizing images from the three rectangular liquid crystal display elements; and a projection lens for enlarging and projecting said synthesized image.
Claim 2
Dependent Claim
257 words
A projection type display apparatus having three rectangular liquid crystal display elements each of which has an entrance side polarizing plate with the same polarizing direction, which is parallel to one side of the respective rectangular liquid crystal display element comprising: a light source producing non-polarized illuminating light; converting means, receiving the non-polarized illuminating light and converting the non-polarized illuminating light to illuminating light having a direction of polarization parallel to one side of the three rectangular liquid crystal display elements including, polarized light separating means for separating the non-polarized illuminating light into two linearly polarized light beams, polarization direction rotating means for rotating the polarization direction of at least one of the two polarized light beams to make the polarization direction of the two light beams identical, and synthesizing means for synthesizing the two polarized light beams so that the optical axes of said two polarized light beams are non-parallel to each other, spectroscope means for separating said linearly polarized light beam into light rays of red, green and blue colors; wherein the three rectangular liquid crystal display elements each permit the respective light rays of red, green and blue colors to pass therethrough, the transmittance of each pixel being controlled by a desired image signal, each of the three rectangular liquid crystal display elements being composed of a pair of polarizing plates and a liquid crystal layer being held therebetween; a light synthesizer for synthesizing images from the three rectangular liquid crystal display elements; and a projection lens for enlarging and projecting said synthesized image.
Claim 3
Dependent Claim
53 words
The projection type display apparatus as defined in claim 1, wherein the polarizing direction of the entrance side polarizing plates of each of the three rectangular liquid crystal display elements is parallel or perpendicular to the longitudinal side direction of the rectangular surfaces of each of the three rectangular liquid crystal display elements.
Claim 4
Dependent Claim
25 words
The apparatus of claim 1, wherein said converting means does not reflect a P-polarized light beam and includes a reflector reflecting an S-polarized light beam.
Claim 5
Dependent Claim
28 words
The apparatus of claim 1, wherein said synthesizing means includes: a prism, receiving the two polarized light beams and merging the two polarized light beams through refraction only.
Claim 6
Dependent Claim
30 words
The projection type display apparatus of claim 4, wherein: said prism receives said two polarized light beams directly from said polarized light separating means and said polarized direction rotating means.
Claim 7
Dependent Claim
244 words
A projection type display apparatus having three rectangular liquid crystal display elements each of which has an entrance side polarizing plate with a polarizing direction parallel to one side of the respective rectangular liquid crystal display element comprising: a light source emitting non-polarized illuminating light; converting means receiving the non-polarized illuminating light and converting the non-polarized illuminating light to illuminating light having a direction of polarization parallel to one side of the three rectangular liquid crystal display elements including, polarized light separating means for separating the illuminating light into two linearly polarized light beams, polarization direction rotating means for rotating the polarization direction of at least one of said two polarized light beams to make the polarization direction of the two light beams identical, and synthesizing means for synthesizing the two polarized light beams whose polarization directions are rotated, with optical axes of said two polarized light beams being non-parallel to each other, a spectroscope, separating the linearly polarized light beam into read, blue and green light rays; wherein the three rectangular liquid crystal display elements respectively receive and emit the red, blue and green light rays and including, horizontal and vertical sides, a pair of polarizing plates having a polarizing direction substantially parallel to one of said horizontal and vertical sides of the liquid crystal display element, and a liquid crystal layer; and a light synthesizer, synthesizing the emitted red, blue and green light rays, emitted from the three rectangular liquid display elements.
Claim 8
Dependent Claim
244 words
A projection type display apparatus having three rectangular liquid crystal display elements each of which has an entrance side polarizing plate with a polarizing direction parallel to one side of the respective rectangular liquid crystal display element comprising: a light source emitting non-polarized illuminating light; converting means receiving the non-polarized illuminating light and converting the non-polarized illuminating light to illuminating light having a direction of polarization parallel to one side of the three rectangular liquid crystal display elements including, polarized light separating means for separating the illuminating light into two linearly polarized light beams, polarization direction rotating means for rotating the polarization direction of at least one of said two polarized light beams to make the polarization direction of the two light beams identical, and synthesizing means for synthesizing the two polarized light beams whose polarization directions are rotated, with optical axes of said two polarized light beams being non-parallel to each other, a spectroscope, separating the linearly polarized light beam into read, blue and green light rays; wherein the three rectangular liquid crystal display elements respectively receive and emit the red, blue and green light rays and including, horizontal and vertical sides, a pair of polarizing plates having a polarizing direction substantially parallel to one of said horizontal and vertical sides of the liquid crystal display element, and a liquid crystal layer; and a light synthesizer, synthesizing the emitted red, blue and green light rays, emitted from the three rectangular liquid display elements.
Claim 9
Dependent Claim
41 words
The projection type display apparatus of claim 6, wherein: said polarized light separating means includes a mirror for reflecting an S-polarized light beam; and said polarization direction rotating means includes a phase plate which receives and rotates said S-polarized light beam.
Claim 10
Dependent Claim
25 words
The apparatus of claim 6, wherein said converting means does not reflect a P-polarized light beam and includes a reflector reflecting an S-polarized light beam.
Claim 11
Dependent Claim
34 words
The apparatus of claim 6, wherein said synthesizing means includes: a prism, receiving the two polarized light beams and merging the two polarized light beams without reflecting either or the two polarized light beams.
Claim 12
Dependent Claim
21 words
The projection type display apparatus of claim 9, wherein: said prism receives said two polarized light beams through a single surface.
Claim 13
Dependent Claim
30 words
The projection type display apparatus of claim 9, wherein: said prism receives said two polarized light beams directly from said polarized light separating means and said polarized direction rotating means.
Claim 14
Dependent Claim
21 words
The projection type display apparatus of claim 11, wherein: said prism receives said two polarized light beams through a single surface.
References Cited (Backward Citations)
US4231640A
Cited
JPS6190584A
Cited
US4850685A
Cited
JPS62133424A
Cited
US4989076A
Cited
JPH01102428A
Cited
US5097323A
Cited
US5105265A
Cited
JPH0212192A
Cited
US5042921A
Cited
US4913529A
Cited
US5200843A
Cited
JPH03150525A
Cited
US5073830A
Cited
JPH03221917A
Cited
US5387991A
Cited
US5299036A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-29 | 2000-04-29 | 2000-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-29 | 2004-04-29 | 2004-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-29 | 2008-04-29 | 2008-10-29 | $7700.00 | Window Closed / Lapsed |