Patent EP0311236A2 successfully refreshed from Google Patents.
EP0311236A2
Expired / Lapsed
EP
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LCD compensation for non-optimum voltage conditions
Assignee: HP Inc
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Filing: 1988-07-19
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Granted: —
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Expires: 2008-07-19
Abstract
Abstract A liquid crystal display (LCD) compensation circuit, operating within a peak voltage limitation, serves to maximize the on/off voltage ratio applied to the LCD while at the same time meeting the LCD threshold voltage specification to thereby optimize the appearance of the liquid crystal display at all times.
Inventors
- 👤 Grant K. Garner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 06:59
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G09; G09G; G09G3/00; G09G3/04; G09G3/16; G09G3/18; G05; G05F; G05F1/00; G05F1/10; G05F1/625; G09G3/20; G09G3/34; G09G3/36
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
162 words
A liquid crystal display compensation circuit, the circuit comprising: reference voltage source means for supplying a desired reference voltage (V A ) to be applied to the liquid crystal display; summer means (10) having a first summing input for receiving the reference voltage (V A ), having a second summing input, and having an output providing a step voltage (V B ); peak voltage function generator means (20) having an input for receiving the step voltage (V B ) and having an output that provides a source of peak voltage (V H ); and feedback function generator means (30) having an input for receiving the peak voltage (V H ) and having an output connected to the second summing input of the summer means (10), the summer means (10) being thereby operative for subtracting the output of the feedback function generator means (30) from the reference voltage (V A ) to produce a continuously updated value of step voltage (V B ).
Claim 2
Dependent Claim
162 words
A liquid crystal display compensation circuit, the circuit comprising: reference voltage source means for supplying a desired reference voltage (V A ) to be applied to the liquid crystal display; summer means (10) having a first summing input for receiving the reference voltage (V A ), having a second summing input, and having an output providing a step voltage (V B ); peak voltage function generator means (20) having an input for receiving the step voltage (V B ) and having an output that provides a source of peak voltage (V H ); and feedback function generator means (30) having an input for receiving the peak voltage (V H ) and having an output connected to the second summing input of the summer means (10), the summer means (10) being thereby operative for subtracting the output of the feedback function generator means (30) from the reference voltage (V A ) to produce a continuously updated value of step voltage (V B ).
Claim 3
Dependent Claim
23 words
A liquid crystal display compensation circuit as in claim 1 wherein the peak voltage function generator means (20) comprises a constant voltage source.
Claim 4
Dependent Claim
22 words
A liquid crystal display compensation circuit as in claim 1 wherein the peak voltage function generator means (20) comprises a voltage multiplier.
Claim 5
Dependent Claim
28 words
A liquid crystal display compensation circuit as in claim 1 wherein the output of the feedback function generator means (30) is a defined fractional function of its input.
Claim 6
Dependent Claim
19 words
A liquid crystal display compensation circuit as in claim 4 wherein the defined fractional function is equal to 0.28.
Claim 7
Dependent Claim
29 words
A liquid crystal display compensation circuit as in claim 1 wherein the output of the feedback function generator means (30) is a defined square root function of its input.
Claim 8
Dependent Claim
30 words
A liquid crystal display compensation circuit as in claim 1 wherein the output of the feedback function generator means (30) is related to its input by a multiple of 0.28.
Claim 9
Dependent Claim
27 words
A liquid crystal display compensation circuit as in claim 1 wherein the summer means (10) and the feedback function generator means (30) comprise a resistor summing amplifier.
References Cited (Backward Citations)
No citation records indexed.
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