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US5319480A
Expired / Lapsed
US
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Liquid crystal half-tone display with gray level uniformity
Assignee: Honeywell Inc
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Filing: 1993-03-19
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Granted: 1994-06-07
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Expires: 2013-03-19
Abstract
Abstract A half-tone liquid crystal display panel having half-tone pixels, each comprising a plurality of sub-pixels including first and second sub-pixels. Activation voltage is supplied to the first sub-pixel from a TFT switch and to the second sub-pixel from the TFT switch through a coupling capacitor. The second sub-pixel includes a storage capacitor. Sensitivity of the activation voltage applied to the second sub-pixel resulting from capacitance non-uniformity across the panel is reduced by forming the coupling capacitor and the storage capacitor of the second sub-pixel with the same depositions utilizing a common dielectric layer. The capacitance of the storage capacitor of the second sub-pixel is designed large compared to the capacitance of the second sub-pixel.
Inventors
- 👤 Richard I. McCartney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:59
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3607; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/136213; G09G3/3611; G09G3/3648; G02F2203/00; G02F2203/30; G09G3/2007; G09G3/2074
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A half-tone pixel in a liquid crystal display, said half-tone pixel having a plurality of sub-pixels including first and second sub-pixels, comprising a switch for applying an activation signal to said first sub-pixel, a first coupling capacitor for coupling said activation signal from said switch to said second sub-pixel, said first coupling capacitor having a first coupling capacitor dielectric, and a storage capacitor coupled to said second sub-pixel, said storage capacitor having a storage capacitor dielectric, said first coupling capacitor dielectric and said storage capacitor dielectric being formed as a common dielectric layer of substantially uniform thickness.
Claim 2
Dependent Claim
97 words
A half-tone pixel in a liquid crystal display, said half-tone pixel having a plurality of sub-pixels including first and second sub-pixels, comprising a switch for applying an activation signal to said first sub-pixel, a first coupling capacitor for coupling said activation signal from said switch to said second sub-pixel, said first coupling capacitor having a first coupling capacitor dielectric, and a storage capacitor coupled to said second sub-pixel, said storage capacitor having a storage capacitor dielectric, said first coupling capacitor dielectric and said storage capacitor dielectric being formed as a common dielectric layer of substantially uniform thickness.
Claim 3
Dependent Claim
48 words
The pixel of claim 1 wherein said second sub-pixel has a capacitance and said storage capacitor has a capacitance, said storage capacitor and said second sub-pixel being constructed and arranged so that said capacitance of said storage capacitor is significantly larger than said capacitance of said second sub-pixel.
Claim 4
Dependent Claim
51 words
The pixel of claim 1 wherein said second sub-pixel has a capacitance and said storage capacitor has a capacitance, said storage capacitor and said second sub-pixel being constructed and arranged so that said capacitance of said storage capacitor is at least five times larger than said capacitance of said second sub-pixel.
Claim 5
Dependent Claim
93 words
The pixel of claim 1 wherein said activation signal applied to said first sub-pixel comprises a first sub-pixel voltage, said activation signal applied to said second sub-pixel comprises a second sub-pixel voltage, said second sub-pixel has a capacitance, and said second sub-pixel voltage is related to said first sub-pixel voltage as follows: V.sub.2 /V.sub.1 =1/[(C.sub.s2 /C.sub.c)+C.sub.lc2 /C.sub.c)+1] where: V 1 =said first sub-pixel voltage V 2 =said second sub-pixel voltage C s2 =capacitance of said storage capacitor C c =capacitance of said first coupling capacitor C lc2 =said capacitance of said second sub-pixel.
Claim 6
Dependent Claim
62 words
The pixel of claim 4 wherein said second sub-pixel has a capacitance and said storage capacitor has a capacitance, said storage capacitor and said second sub-pixel being constructed and arranged so that said capacitance of said storage capacitor is significantly larger than said capacitance of said second sub-pixel with C c being correspondingly large to preserve the V 2 /V 1 ratio.
Claim 7
Dependent Claim
70 words
The pixel of claim 1 further including a plurality of coupling capacitors, including said first coupling capacitor, for coupling said activation signal from said switch to said second sub-pixel, said plurality of coupling capacitors having a respective plurality of coupling capacitor dielectrics, including said first coupling capacitor dielectric, said plurality of coupling capacitor dielectrics and said storage capacitor dielectric being formed as a common dielectric layer of substantially uniform thickness.
Claim 8
Dependent Claim
35 words
The pixel of claim 6 wherein said plurality of coupling capacitors comprise a plurality of serially connected coupling capacitors for coupling said activation signal from said switch to respective ones of said plurality of sub-pixels.
Claim 9
Dependent Claim
99 words
In a half-tone liquid crystal display having a half-tone pixel, said half-tone pixel having a plurality of sub-pixels including first and second sub-pixels, said second sub-pixel having a storage capacitor associated therewith, said display including a switch for applying an activation signal to said first sub-pixel, said half-tone pixel including a first coupling capacitor for coupling said activation signal from said switch to said second sub-pixel; a method for reducing sensitivity of said activation signal coupled to said second sub-pixel, comprising forming said first coupling capacitor and said storage capacitor with a common dielectric layer of substantially uniform thickness.
Claim 10
Dependent Claim
99 words
In a half-tone liquid crystal display having a half-tone pixel, said half-tone pixel having a plurality of sub-pixels including first and second sub-pixels, said second sub-pixel having a storage capacitor associated therewith, said display including a switch for applying an activation signal to said first sub-pixel, said half-tone pixel including a first coupling capacitor for coupling said activation signal from said switch to said second sub-pixel; a method for reducing sensitivity of said activation signal coupled to said second sub-pixel, comprising forming said first coupling capacitor and said storage capacitor with a common dielectric layer of substantially uniform thickness.
Claim 11
Dependent Claim
23 words
The method of claim 8 further comprising forming said storage capacitor with a capacitance substantially greater than the capacitance of said second sub-pixel.
Claim 12
Dependent Claim
56 words
The method of claim 8 wherein said half-tone pixel further includes a plurality of coupling capacitors, including said first coupling capacitor, for coupling said activation signal from said switch to said second sub-pixel, said method further comprising forming said plurality of coupling capacitors and said storage capacitor with a common dielectric layer of substantially uniform thickness.
References Cited (Backward Citations)
US4840460A
Cited
US5126865A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-06 | 1997-12-06 | 1998-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-06 | 2001-12-06 | 2002-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-06 | 2005-12-06 | 2006-06-07 | $7700.00 | Window Closed / Lapsed |