Patent US5253074A successfully refreshed from Google Patents.
US5253074A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature compensated color LCD projector
Assignee: US Philips Corp
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Filing: 1991-12-18
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Granted: 1993-10-12
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Expires: 2011-12-18
Abstract
Abstract In a projection display device based on one or more (twisted nematic) LCDs (4), simple temperature compensation is possible by optimizing the d.Δn value (n) at the maximal operating temperature. The associated transmission/voltage characteristics at different temperatures then extend substantially parallel so that it is possible to compensate for temperature changes by means of a simple voltage compensation.
Inventors
- 👤 Franciscus J. M. Wortel
- 👤 Ingrid E. J. R. Heynderickx
- 👤 Peter E. Wierenga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:11
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133382; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; H; H04; H04N; H04N5/00; H04N5/74; H04N5/7416; H04N5/7441; H04N9/00; H04N9/12; H04N9/31; H04N9/3141; H04N9/3144; G09G2320/00; G09G2320/04; G09G2320/041
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
112 words
A projection display device comprising at least one liquid crystal display device having a layer of liquid crystalline material between two supporting plates provided with electrodes which define at least one pixel, via which electrodes a voltage can be applied across the pixel, characterized in that in at least one of the extreme transmission states the product d.Δn of the thickness d of the layer of liquid crystalline material and the difference in refractive index Δn is chosen to be such that d.Δn at the maximum temperature of use is 0.45-0.50 μm, the device being also provided with means for correcting the value of an applied voltage in dependence on the temperature.
Claim 2
Dependent Claim
112 words
A projection display device comprising at least one liquid crystal display device having a layer of liquid crystalline material between two supporting plates provided with electrodes which define at least one pixel, via which electrodes a voltage can be applied across the pixel, characterized in that in at least one of the extreme transmission states the product d.Δn of the thickness d of the layer of liquid crystalline material and the difference in refractive index Δn is chosen to be such that d.Δn at the maximum temperature of use is 0.45-0.50 μm, the device being also provided with means for correcting the value of an applied voltage in dependence on the temperature.
Claim 3
Dependent Claim
46 words
A device as claimed in claim 1, characterized in that the electrodes define a matrix of pixels arranged in rows and columns, in which the column electrodes are driven by means of corrected or uncorrected data voltages when a row of pixels is being selectively driven.
Claim 4
Dependent Claim
29 words
A device as claimed in claim 1, characterized in that the liquid crystal display device is present between mutually perpendicularly crossed polarizers and is light-transmissive in an extreme state.
Claim 5
Dependent Claim
23 words
A device as claimed in claim 1, characterized in that the maximal temperature of use of the liquid crystalline material is 80° C.
Claim 6
Dependent Claim
24 words
A device as claimed in claim 1, characterized in that the product d.Δn at room temperature (20° C.) is between 0.50 and 0.65 μm.
Claim 7
Dependent Claim
42 words
A device as claimed in claim 1, characterized in that a correction value for the voltages is determined by means of temperature measurement in the liquid crystal display device, and in that a measured temperature difference is converted into a correction signal.
Claim 8
Dependent Claim
49 words
A device as claimed in claim 1, characterized in that a correction value for the voltages are determined by mean of light intensity measurement after the light has passed through the liquid crystal display device and in that a measured light intensity difference is converted into a correction signal.
Claim 9
Dependent Claim
34 words
A liquid crystal display device for use in a device as claimed in claim 6, characterized in that the liquid crystal display device also comprises a thermocouple, a temperature sensor or a temperature-sensitive resistor.
Claim 10
Dependent Claim
36 words
A liquid crystal display device for use in a device as claimed in claim 7, characterized in that the liquid crystal display device is provided with an optical sensor and a pixel which is always light-transmissive.
Claim 11
Dependent Claim
28 words
A device as claimed in claim 2, characterized in that the liquid crystal display device is present between mutually perpendicularly crossed polarizers and is light-transmissive in extreme state.
Claim 12
Dependent Claim
22 words
A device as claimed claim 3, characterized in that the maximal temperature of use of the liquid crystalline material is 80° C.
Claim 13
Dependent Claim
24 words
A device as claimed in claim 4, characterized in that the product d.Δn at room temperature (20° C.) is between 0.50 and 0.65 μm.
Claim 14
Dependent Claim
42 words
A device as claimed in claim 3, characterized in that a correction value for the voltages is determined by means of a temperature measurement in the liquid crystal device, and in that a measured temperature difference is converted into a correction signal.
Claim 15
Dependent Claim
50 words
A device as claimed in claim 3, characterized in that a correction value for the voltages are determined by means of a light intensity measurement after the light has passed through the liquid crystal display device and in that a measured light intensity difference is converted into a correction signal.
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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) | 1996-10-11 | 1997-04-12 | 1997-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-11 | 2001-04-12 | 2001-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-11 | 2005-04-12 | 2005-10-12 | $7700.00 | Window Closed / Lapsed |