US5491525A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Illumination unit for liquid crystal projection display apparatus and liquid crystal display apparatus having it used
Assignee: Hitachi Consumer Electronics Co Ltd
•
Filing: 1993-11-19
•
Granted: 1996-02-13
•
Expires: 2013-11-19
Abstract
Abstract A bulb (4) of lamp (1) has a reflection film (2) or reflection mirror (9) to make light components going outside a reflector (3) direct to the reflector (3) to reflect. If the lamp (1) is a spot light source, a light emission center is positioned at a center of spherical reflection mirror (9). If the lamp (1) is not a spot light source, the reflection mirror (9) is made ellipsoid and at its two focal points, ends of two light emitting electrodes are positioned. Also, the lamp (1) having the reflection mirror (9) is used in the illumination unit for a liquid crystal display apparatus to increase the brightness of the image projected onto the screen (26). Further, the liquid crystal display device (23) has within a liquid crystal display device (23) a microlens array for collecting the incoming light into an area of each picture element electrode (39) to increase the light utilization efficiency of the liquid crystal display device (23).
Inventors
- 👤 Futoshi Yamasaki
- 👤 Yoshio Ariki
- 👤 Masaharu Deguchi
- 👤 Takashi Kakuda
- 👤 Takanori Hisada
- 👤 Takesuke Maruyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:18
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/312; H04N9/3141; H04N9/315
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
The illumination unit for a projection type liquid crystal display comprising: at least a light source for emitting light, the light source including two electrodes for emitting light; a reflector for focusing the light emitted from the light source onto a liquid crystal display element; and an elliptical reflecting mirror for reflecting the light emitted from the light source toward said reflector, the elliptical reflecting mirror having two focal points, the two focal points being positioned to coincide with ends of the two electrodes of the light source, respectively.
Claim 2
Dependent Claim
89 words
The illumination unit for a projection type liquid crystal display comprising: at least a light source for emitting light, the light source including two electrodes for emitting light; a reflector for focusing the light emitted from the light source onto a liquid crystal display element; and an elliptical reflecting mirror for reflecting the light emitted from the light source toward said reflector, the elliptical reflecting mirror having two focal points, the two focal points being positioned to coincide with ends of the two electrodes of the light source, respectively.
Claim 3
Dependent Claim
88 words
A projection type liquid crystal display unit comprising: a light source for emitting light; a reflector for focusing the light from said light source, the reflector having a shape which satisfies the following conditional expression: D≧4f≧0.75×D where D indicates an aperture of the reflector and f indicates a focal length of the reflector; a liquid crystal display element which is illuminated by the light emitted from said light source, and; a projection lens for enlarging and projecting an image on said liquid crystal display element onto a screen.
Claim 4
Dependent Claim
88 words
A projection type liquid crystal display unit comprising: a light source for emitting light; a reflector for focusing the light from said light source, the reflector having a shape which satisfies the following conditional expression: D≧4f≧0.75×D where D indicates an aperture of the reflector and f indicates a focal length of the reflector; a liquid crystal display element which is illuminated by the light emitted from said light source, and; a projection lens for enlarging and projecting an image on said liquid crystal display element onto a screen.
Claim 5
Dependent Claim
83 words
A projection type liquid crystal display comprising: a light source for emitting light, a reflector for focusing and emitting the light from the light source onto a liquid crystal display element which is illuminated by the light from said light source, a projection lens for enlarging and projecting an image on said liquid crystal display element onto a screen, and a dichroic reflecting mirror which is formed in said light source by a dichroic film which transmits thermic rays and reflects visible rays.
Claim 6
Dependent Claim
83 words
A projection type liquid crystal display comprising: a light source for emitting light, a reflector for focusing and emitting the light from the light source onto a liquid crystal display element which is illuminated by the light from said light source, a projection lens for enlarging and projecting an image on said liquid crystal display element onto a screen, and a dichroic reflecting mirror which is formed in said light source by a dichroic film which transmits thermic rays and reflects visible rays.
Claim 7
Dependent Claim
114 words
A projection type liquid crystal display unit comprising: a light source for emitting light, a liquid crystal display element which is illuminated by light emitted from said light source, a projection lens for enlarging and projecting an image from said liquid crystal display element onto a screen; and, an elliptical reflector for focusing light from the light source, the reflector having a shape which satisfies the following conditional expression: (D×L)/(D+y)<f<(D×L)/(D+y) where L indicates a distance from a top of the reflector to the liquid crystal display element, f is a focal length of the reflector, D is an aperture of the reflector, and y is a diagonal length of the liquid crystal display element.
Claim 8
Dependent Claim
114 words
A projection type liquid crystal display unit comprising: a light source for emitting light, a liquid crystal display element which is illuminated by light emitted from said light source, a projection lens for enlarging and projecting an image from said liquid crystal display element onto a screen; and, an elliptical reflector for focusing light from the light source, the reflector having a shape which satisfies the following conditional expression: (D×L)/(D+y)<f<(D×L)/(D+y) where L indicates a distance from a top of the reflector to the liquid crystal display element, f is a focal length of the reflector, D is an aperture of the reflector, and y is a diagonal length of the liquid crystal display element.
Claim 9
Dependent Claim
125 words
A projection type liquid crystal display unit comprising: a light source for emitting light, a reflector for focusing the light from the light source, a condenser lens for focusing the light from the reflector, a liquid crystal display element which is to be illuminated by said focused light, a projection lens for enlarging and projecting an image from said liquid crystal display element onto a screen, and the reflector having a shape which satisfies the following conditional expression: (D-LO)/(D+y)<f.sub.CL <(D-LO)/(D-y) where LO indicates a distance from the condenser lens to the liquid crystal display element, f CL is a focal length of the condenser lens, D is an aperture of the condenser lens, and y is a diagonal length of the liquid crystal display element.
Claim 10
Dependent Claim
125 words
A projection type liquid crystal display unit comprising: a light source for emitting light, a reflector for focusing the light from the light source, a condenser lens for focusing the light from the reflector, a liquid crystal display element which is to be illuminated by said focused light, a projection lens for enlarging and projecting an image from said liquid crystal display element onto a screen, and the reflector having a shape which satisfies the following conditional expression: (D-LO)/(D+y)<f.sub.CL <(D-LO)/(D-y) where LO indicates a distance from the condenser lens to the liquid crystal display element, f CL is a focal length of the condenser lens, D is an aperture of the condenser lens, and y is a diagonal length of the liquid crystal display element.
References Cited (Backward Citations)
US1867138A
Cited
US4422135A
Cited
JPS5866909A
Cited
JPS6063273A
Cited
JPS6174076A
Cited
JPS6174075A
Cited
JPS61114375A
Cited
JPS61114376A
Cited
JPH01120192A
Cited
US5098184A
Cited
US5056912A
Cited
JPH03131835A
Cited
US5142387A
Cited
JPH045643A
Cited
US5192962A
Cited
US5217299A
Cited
US5295005A
Cited
JPH04328538A
Cited
JPH0511343A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-12 | 1999-08-14 | 2000-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-12 | 2003-08-14 | 2004-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-12 | 2007-08-14 | 2008-02-13 | $7700.00 | Window Closed / Lapsed |