US4909601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Projection-type color display device with light valves positioned at unequal distances from the light source
Assignee: Seiko Epson Corp
•
Filing: 1988-04-13
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Granted: 1990-03-20
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Expires: 2008-04-13
Abstract
Abstract A projection-type display device for producing a well balanced color image without the use of a neutral density filter. The device includes three liquid crystal light valves associated with the three primary colors and two dichroic mirrors. A light source generates colored light. The optical length between the light source and the light valve associated with the primary color of the colored light having the highest level of luminous intensity is greater than the optical lengths between the light source and each of the other two light valves. One of the three liquid crystal light valves is driven by circuitry to produce an image which is a mirror image of the images produced by the other two light valves.
Inventors
- 👤 Akitaka Yajima
- 👤 Junichi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:47
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/3105
Claims Analysis
Total Claims: 53
Claim 1
Independent Claim
117 words
A projection-type display device comprising: a light source for producing light having a plurality of colors; segregating means for segregating the light into the plurality of colors including at least a first color and a second color; and liquid crystal light valve means including at least a first light valve and a second light valve, said first light valve positioned to receive said first color and said second light valve positioned to receive said second color; wherein the optical lengths from the light source to the first light valve and from the light source to the second light valve are unequal and are based on the luminous intensities of the first color and the second color, respectively.
Claim 2
Dependent Claim
117 words
A projection-type display device comprising: a light source for producing light having a plurality of colors; segregating means for segregating the light into the plurality of colors including at least a first color and a second color; and liquid crystal light valve means including at least a first light valve and a second light valve, said first light valve positioned to receive said first color and said second light valve positioned to receive said second color; wherein the optical lengths from the light source to the first light valve and from the light source to the second light valve are unequal and are based on the luminous intensities of the first color and the second color, respectively.
Claim 3
Dependent Claim
23 words
The projection-type display device of claim 1, wherein each light valve of the liquid crystal light valve means is a liquid crystal panel.
Claim 4
Dependent Claim
33 words
The projection-type display device of claim 1, wherein the first color has the greatest luminous intensity of all the colors produced by the light source and is associated with the longest optical length.
Claim 5
Dependent Claim
33 words
The projection-type display device of claim 2, wherein the first color has the greatest luminous intensity of all the colors produced by the light source and is associated with the longest optical length.
Claim 6
Dependent Claim
33 words
The projection-type display device of claim 1, wherein the second color has the smallest luminous intensity of all the colors produced by the light source and is associated with the shortest optical length.
Claim 7
Dependent Claim
33 words
The projection-type display device of claim 2, wherein the second color has the smallest luminous intensity of all the colors produced by the light source and is associated with the shortest optical length.
Claim 8
Dependent Claim
33 words
The projection-type display device of claim 3, wherein the second color has the smallest luminous intensity of all the colors produced by the light source and is associated with the shortest optical length.
Claim 9
Dependent Claim
29 words
The projection-type display device of claim 1, wherein the liquid crystal light valve means includes a third light valve, and third light valve positioned to receive a third color.
Claim 10
Dependent Claim
13 words
The projection-type display device of claim 3, wherein the first color is red.
Claim 11
Dependent Claim
13 words
The projection-type display device of claim 7, wherein the first color is red.
Claim 12
Dependent Claim
13 words
The projection-type display device of claim 5, wherein the second color is blue.
Claim 13
Dependent Claim
13 words
The projection-type display device of claim 10, wherein the second color is blue.
Claim 14
Dependent Claim
18 words
The projection-type display device of claim 12, in which a tungsten halogen lamp serves as the light source.
Claim 15
Dependent Claim
86 words
The projection-type display device of claim 8, wherein the first light valve includes means for producing a first image, the second light valve includes means for producing a second image and the third light valve includes means for producing a third image and further including circuit means for controlling the images produced by the liquid crystal light valves wherein the third image produced by the third liquid crystal light valve is a mirror image of the first image and a mirror image of the second image.
Claim 16
Dependent Claim
29 words
The projection-type display device of claim 12, wherein the liquid crystal light valve means includes a third light valve, said third light valve positioned to receive a third color.
Claim 17
Dependent Claim
86 words
The projection-type display device of claim 15, wherein the first light valve includes means for producing a first image, the second light valve includes means for producing a second image and the third light valve includes means for producing a third image and further including circuit means for controlling the images produced by the liquid crystal light valves wherein the third image produced by the third liquid crystal light valve is a mirror image of the first image and a mirror image of the second image.
Claim 18
Dependent Claim
18 words
The projection-type display device of claim 16, in which a tungsten halogen lamp serves as the light source.
Claim 19
Dependent Claim
25 words
The projection-type display device of claim 17, further including light guide means for guiding the colored light towards each of the liquid crystal light valves.
Claim 20
Dependent Claim
21 words
The projection-type display device of claim 18, further including light protection means for shielding portions of the circuit means from light.
Claim 21
Dependent Claim
28 words
The projection-type display device of claim 19, further including prism means for reversing the direction of the image produced by said two of three liquid crystal light valves.
Claim 22
Dependent Claim
13 words
The projection-type display device of claim 3, wherein the first color is blue.
Claim 23
Dependent Claim
13 words
The projection-type display device of claim 7, wherein the first color is blue.
Claim 24
Dependent Claim
13 words
The projection-type display device of claim 5, wherein the second color is red.
Claim 25
Dependent Claim
13 words
The projection-type display device of claim 22, wherein the second color is red.
Claim 26
Dependent Claim
17 words
The projection-type display device of claim 24, in which a xenon lamp serves as the light source.
Claim 27
Dependent Claim
29 words
The projection-type display device of claim 24, wherein the liquid crystal light valve means includes a third light valve, said third light valve positioned to receive a third color.
Claim 28
Dependent Claim
86 words
The projection-type display device of claim 26, wherein the first light valve includes means for producing a first image, the second light valve includes means for producing a second image and the third light valve includes means for producing a third image and further including circuit means for controlling the images produced by the liquid crystal light valves wherein the third image produced by the third liquid crystal light valve is a mirror image of the first image and a mirror image of the second image.
Claim 29
Dependent Claim
17 words
The projection-type display device of claim 27, in which a xenon lamp serves as the light source.
Claim 30
Dependent Claim
25 words
The projection-type display device of claim 28, further including light guide means for guiding the colored light towards each of the liquid crystal light valves.
Claim 31
Dependent Claim
21 words
The projection-type display device of claim 29, further including light protection means for shielding portions of the circuit means from light.
Claim 32
Dependent Claim
23 words
The projection-type display device of claim 30, further including prism means for reversing the directions of the first image and the second image.
Claim 33
Dependent Claim
13 words
The projection-type display device of claim 3, wherein the first color is green.
Claim 34
Dependent Claim
13 words
The projection-type display device of claim 7, wherein the first color is green.
Claim 35
Dependent Claim
13 words
The projection-type display device of claim 5, wherein the second color is blue.
Claim 36
Dependent Claim
13 words
The projection-type display device of claim 33, wherein the second color is blue.
Claim 37
Dependent Claim
18 words
The projection-type display device of claim 35, in which a metal halide lamp serves as the light source.
Claim 38
Dependent Claim
29 words
The projection-type display device of claim 35, wherein the liquid crystal light valve means includes a third light valve, said third light valve positioned to receive a third color.
Claim 39
Dependent Claim
86 words
The projection-type display device of claim 37, wherein the first light valve includes means for producing a first image, the second light valve includes means for producing a second image and the third light valve includes means for producing a third image and further including circuit means for controlling the images produced by the liquid crystal light valves wherein the third image produced by the third liquid crystal light valve is a mirror image of the first image and a mirror image of the second image.
Claim 40
Dependent Claim
18 words
The projection-type display device of claim 38, in which a metal halide lamp serves as the light source.
Claim 41
Dependent Claim
25 words
The projection-type display device of claim 39, further including light guide means for guiding the colored light towards each of the liquid crystal light valves.
Claim 42
Dependent Claim
21 words
The projection-type display device of claim 40, further including light protection means for shielding portions of the circuit means from light.
Claim 43
Dependent Claim
28 words
The projection-type display device of claim 41, further including prism means for reversing the direction of the image produced by said two of three liquid crystal light valves.
Claim 44
Dependent Claim
34 words
The projection-type liquid crystal light valve of claim 14, further including integrating means for combining the first, second and third images and producing a synthesized image, and projecting means for projecting the synthesized image.
Claim 45
Dependent Claim
18 words
The projection-type display device of claim 9, in which a tungsten halogen lamp serves as the light source.
Claim 46
Dependent Claim
17 words
The projection-type display device of claim 21, in which a xenon lamp serves as the light source.
Claim 47
Dependent Claim
18 words
The projection-type display device of claim 32, in which a metal halide lamp serves as the light source.
Claim 48
Dependent Claim
26 words
The projection-type display device of claim 8, in which said first liquid crystal light valve is disposed between the second and third liquid crystal light valves.
Claim 49
Dependent Claim
25 words
The projection-type display device of claim 1, further including light guide means for guiding the colored light towards each of the liquid crystal light valves.
Claim 50
Dependent Claim
21 words
The projection-type display device of claim 14, further including light protection means for shielding portions of the circuit means from light.
Claim 51
Dependent Claim
23 words
The projection-type display device of claim 14, further including prism means for reversing the directions of the first image and the second image.
Claim 52
Independent Claim
149 words
A method for displaying an image projected from a liquid crystal display device which includes a first liquid crystal light valve, a second liquid crystal light valve and a third liquid crystal light valve, comprises: segregating light produced by a light source into its primary colors; positioning segregating means within the device so that the optical lengths between the light source and the three liquid crystal light valves are unequal and based on the luminous intensity of the primary color associated with the respective light valve produced by the light source; producing a first image from the first liquid crystal valve, a second image from the second liquid crystal liquid valve and a third image from the third liquid crystal light valve; and controlling the images produced by the liquid crystal light valves whereby the first image is a mirror image of the second image and the third image.
Claim 53
Independent Claim
149 words
A method for displaying an image projected from a liquid crystal display device which includes a first liquid crystal light valve, a second liquid crystal light valve and a third liquid crystal light valve, comprises: segregating light produced by a light source into its primary colors; positioning segregating means within the device so that the optical lengths between the light source and the three liquid crystal light valves are unequal and based on the luminous intensity of the primary color associated with the respective light valve produced by the light source; producing a first image from the first liquid crystal valve, a second image from the second liquid crystal liquid valve and a third image from the third liquid crystal light valve; and controlling the images produced by the liquid crystal light valves whereby the first image is a mirror image of the second image and the third image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |