Patent EP0536975A2 successfully refreshed from Google Patents.
EP0536975A2
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EP
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Method of driving surface-stabilised ferroelectric liquid crystal display element for increasing the number of gray scales
Assignee: Fujitsu Ltd
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Filing: 1992-10-06
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Granted: —
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Expires: 2012-10-06
Abstract
Abstract A method of driving a surface-stabilised ferroelectric liquid crystal display element uses a selection voltage (Vs), intermediate-selection voltage (Vhs), and non-selection voltage (Vns). Relationships between the selection voltage (Vs), intermediate-selection voltage (Vhs), and non-selection voltage (Vns) of a drive signal are changed, or absolute levels of the selection voltage (Vs), intermediate-selection voltage (Vhs), and non-selection voltage (Vns) are changed in order that a plurality of gray gradations of the surface-stabilised ferroelectric liquid crystal display element can be obtained.
Inventors
- 👤 Akihiro c/o Fujitsu Limited Mochizuki
- 👤 Shigeo c/o Fujitsu Limited Kasahara
- 👤 Katsusada C/O Fujitsu Limited Motoyoshi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:19
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3622; G09G3/3629; G09G2310/00; G09G2310/06; G09G2320/00; G09G2320/02; G09G2320/028; G09G3/2007; G09G3/2011; G09G3/2014
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
83 words
A method of driving a surface-stabilised ferroelectric liquid crystal display element by the application of pulses at a selection voltage (Vs), intermediate-selection voltage (Vhs), or a non-selection voltage (Vns) to the electrodes of the display element, characterised in that in order to display a plurality of gray gradations of the surface-stabilised ferroelectric liquid crystal display element the relationships between or absolute values of the selection voltage (Vs), intermediate-selection voltage (Vhs), and non-selection voltage (Vns) of a drive signal are varied between adjacent frames.
Claim 2
Independent Claim
54 words
A method of driving a surface-stabilised ferroelectric liquid crystal display element driven by a drive signal, characterised in that the said drive signal includes at least two positive voltage levels and two negative voltage levels applied to at least one of scan and signal electrodes (4,3) of the surface-stabilised ferroelectric liquid crystal display element.
Claim 3
Dependent Claim
21 words
A method according to claim 1 or 2 wherein the voltage levels of the drive signal are varied between every frame.
Claim 4
Dependent Claim
21 words
A method according to claim 1 or 2, wherein the voltage levels of the drive signal are varied every several frames.
Claim 5
Independent Claim
41 words
A method according to any preceding claim in which the method further uses a pulse modulation method, wherein the pulse width of each of the selection voltage pulse, intermediate-selection voltage pulse and non-selection voltage pulse are variable for each selection signal.
Claim 6
Independent Claim
18 words
A method according to any preceding claim in which said method further uses a domain size control method.
Claim 7
Independent Claim
16 words
A method according to any preceding claim in which the method further uses a dithering method.
Claim 8
Independent Claim
22 words
A method according to any preceding claim, wherein the voltage levels of the drive signal include at least two different pulse widths.
Claim 9
Independent Claim
33 words
A method according to any preceding claim, wherein the relationships between the selection voltage (Vs), intermediate-selection voltage (Vhs) and non-selection voltage (Vns) alternate between ratios of 4:2:1, 4:2:1.5, 4:2:2, or 4:1:1 between frames.
Claim 10
Dependent Claim
74 words
A surface-stabilised liquid crystal display having scan electrodes (4) and signal electrodes (3) to which are applied pulses at a selection voltage (Vs), intermediate-selection voltage (Vhs) or a non-selection voltage (Vns), wherein there is provided a means (14) of varying the relationships between or absolute values of the selection voltage (Vs), intermediate-selection voltage (Vhs) and non-selection voltage (Vns) in order to display a plurality of gray gradations of the surface-stabilised ferroelectric liquid crystal display.
References Cited (Backward Citations)
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