EP0149899A2
Expired / Lapsed
EP
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A liquid crystal display device
Assignee: Seiko Instruments Inc
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Filing: 1984-12-07
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Granted: —
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Expires: 2004-12-07
Abstract
Abstract A liquid crystal display device utilises a ferro-electric liquid crystal material for example a chiral smectic liquid crystal material. The display device is driven by a time-sharing system. The change of display is effected by applying a selected voltage to the ferro-electric liquid crystal material and thereafter the display state may be maintained by applying an AC pulse voltage.
Inventors
- 👤 Takamasa Seiko Instruments And Harada
- 👤 Masaaki Seiko Instruments And Taguchi
- 👤 Koji Seiko Instruments And Iwasa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 17:21
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3674; G09G3/3681; G09G3/3622; G09G3/3629; G09G3/3685; G09G3/3692; G09G2310/00; G09G2310/06; G09G2320/00; G09G2320/02; G09G2320/028; G09G2320/04; G09G2320/041; G09G3/2007; G09G3/2011
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
24 words
A liquid crystal display device characterised by including a ferro-electric liquid crystal material, and drive means for driving the display device using time sharing.
Claim 2
Dependent Claim
24 words
A liquid crystal display device characterised by including a ferro-electric liquid crystal material, and drive means for driving the display device using time sharing.
Claim 3
Dependent Claim
38 words
A liquid crystal display device as claimed in claim 1 characterised in that the ferro-electric liquid crystal material is disposed between a pair of electrodes to form a display cell which is disposed between a pair of polarisers.
Claim 4
Dependent Claim
34 words
A liquid crystal display device as claimed in claim 2 characterised in that the axes of the molecules of the ferro-electric liquid crystal material are inclined to the plane of polarisation of the polarisers.
Claim 5
Dependent Claim
36 words
A liquid crystal display device as claimed in any preceding claim characterised in that the drive means is arranged to apply an AC pulse voltage to the ferro-electric liquid crystal material to maintain a display state.
Claim 6
Dependent Claim
45 words
A liquid crystal display device as claimed in any of claims 1 to 3 characterised in that the drive means is arranged to apply an AC pulse voltage to the ferro-electric liquid crystal material and thereafter forming an open circuit to maintain a display state.
Claim 7
Dependent Claim
78 words
A liquid crystal display device as claimed in claim 1 characterised in that the drive means are such that a change of display state is effected by applying an operating voltage (±V ) having a predetermined pulse amplitude and width to the ferro-electric liquid crystal material and the changed display state is held by applying an AC pulse voltage having a pulse amplitude and width at least one of which is less than that of the operating voltage.
Claim 8
Dependent Claim
22 words
A liquid crystal display device as claimed in claim 6 characterised in that the operating voltage (±V ) contains a DC component.
Claim 9
Dependent Claim
23 words
A liquid crystal display device as claimed in claim 6 characterised in that the operating voltage iV a p contains no DC component.
Claim 10
Dependent Claim
47 words
A liquid crystal display device as claimed in any of claims 6 to 8 characterised by scanning means for scanning to give alternately a waveform with a plurality corresponding to the operating voltage in an ON state or OFF state and a waveform with the opposite polarity.
Claim 11
Dependent Claim
68 words
A liquid crystal display device as claimed in any of claims 6 to 8 characterised in that the drive means is arranged to apply a predetermined voltage which corresponds to an ON state or an OFF state to a picture element located on a scanning electrode which is N lines beyond a selected scanning line, and a display state is produced by the existence of an opposite polarity.
Claim 12
Dependent Claim
58 words
A liquid crystal display device as claimed in any of claims 6 to 8 characterised in that the driving means is arranged to float, elevates driving frequency toward a high level or applies an alternating current pulse having equal levels in positive and negative directions, after a scanning for an ON or OFF state is performed several times.
Claim 13
Dependent Claim
36 words
A liquid crystal display device as claimed in any of claims 6 to 8 characterised in that the driving means is arranged to form a tone display by modulating the pulse width of the operating voltage.
Claim 14
Dependent Claim
31 words
A liquid crystal display device as claimed in any preceding claim characterised by a temperature compensation means for compensating for the effects of change of temperature by altering a driving frequency.
Claim 15
Dependent Claim
37 words
A liquid crystal display device as claimed in any of claims 1 to 12 characterised by temperature compensation means for compensating for the effects of change of temperature by adjusting said operating voltage (V a p ).
Claim 16
Dependent Claim
155 words
A liquid crystal display device as claimed in claim 6 characterised in that the drive means is such that, in the case of selecting two alignment conditions of the molecules of the ferro-electric liquid crystal material which displays an ON or OFF state by a direct current voltage (+V ap or -V ) having a predetermined time width, a scanning time for scanning one scanning electrode is divided into two time width bands, a voltage (+V or - V ) which selects a molecular alignment ap ap condition for the ON or OFF state of a picture element is applied thereto within a first time width band, and a selecting voltage (-V or +V ap ) which has a polarity opposite to that of said ap first time width band is selectively applied to said each picture element in the second time width band, whereby the molecular alignment condition in each picture element is determined.
Claim 17
Dependent Claim
24 words
A liquid crystal display device as claimed in any preceding claim characterised in that the ferro-electric liquid crystal material has a chiral smectic phase.
Claim 18
Dependent Claim
135 words
A smectic liquid crystal display device characterised by comprising in combination: a liquid crystal panel which is composed of a pair of opposed base plates on each of which scanning electrodes and an alignment membrane are formed so that said alignment membranes are opposed inwardly, a smectic liquid crystal compound which is inserted into a gap between said base plates, the gap between said base plates being less than the spiral pitch of said liquid crystal compound; a means for generating a liquid crystal operating voltage in a reverse direction in a first half of an electrode selecting condition, a liquid crystal operating voltage in a forward direction in a second half of the electrode selecting condition and an alternating voltage which is less than the liquid crystal threshold voltage in a non-electrode selecting condition.
Claim 19
Dependent Claim
135 words
A smectic liquid crystal display device characterised by comprising in combination: a liquid crystal panel which is composed of a pair of opposed base plates on each of which scanning electrodes and an alignment membrane are formed so that said alignment membranes are opposed inwardly, a smectic liquid crystal compound which is inserted into a gap between said base plates, the gap between said base plates being less than the spiral pitch of said liquid crystal compound; a means for generating a liquid crystal operating voltage in a reverse direction in a first half of an electrode selecting condition, a liquid crystal operating voltage in a forward direction in a second half of the electrode selecting condition and an alternating voltage which is less than the liquid crystal threshold voltage in a non-electrode selecting condition.
Claim 20
Dependent Claim
17 words
A liquid crystal display device utilising a ferro-electric liquid crystal, the display being driven in time sharing.
Claim 21
Dependent Claim
17 words
A liquid crystal display device utilising a ferro-electric liquid crystal, the display being driven in time sharing.
Claim 22
Dependent Claim
133 words
A smectic liquid crystal display device comprising in combination: a liquid crystal pannel which is composed of a pair of base plates in which a scanning electrode and alignment membrane as shaped on a surface thereof are opposed respectively so that said alignment membranes are opposed inwardly, a smectic liquid crystal compound which is inserted between said base plates, a gap between said base plates which is limited less than a spiral pitch of said liquid crystal compound; a means for generating a liquid crystal operating voltage of a reverse direction in the first half of an electrode selecting condition, a liquid crystal operating voltage of a forward direction in a latter half of an electrode selecting condition and an alternating voltage which is less than liquid crystal voltage in non-electrode selecting condition.
Claim 23
Dependent Claim
133 words
A smectic liquid crystal display device comprising in combination: a liquid crystal pannel which is composed of a pair of base plates in which a scanning electrode and alignment membrane as shaped on a surface thereof are opposed respectively so that said alignment membranes are opposed inwardly, a smectic liquid crystal compound which is inserted between said base plates, a gap between said base plates which is limited less than a spiral pitch of said liquid crystal compound; a means for generating a liquid crystal operating voltage of a reverse direction in the first half of an electrode selecting condition, a liquid crystal operating voltage of a forward direction in a latter half of an electrode selecting condition and an alternating voltage which is less than liquid crystal voltage in non-electrode selecting condition.
References Cited (Backward Citations)
No citation records indexed.
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