EP0373565A2
Expired / Lapsed
EP
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Method of driving a display unit
Assignee: Panasonic Holdings Corp
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Filing: 1989-12-11
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Granted: —
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Expires: 2009-12-11
Abstract
Abstract A method of driving a display unit having matrix-arranged pixel eloectrodes (A) each connected via a capacitor (8) to a first line, each pixel electrode being connected to a switching element (3) which is electrically connected to an image signal line (6) and scan signal line (1), and display material held between the pixel electrode and opposing electrode and being AC driven, wherein an image signal voltage (Vsig) is transmitted to the pixel electrode during an on-period of the switching element, and a modulating signal (Ve) with its voltage reversing alternately for each field is applied to the first line during an off-period of the switching element, thereby changing the potential of the pixel electrode so that the changed potential is superposed upon, or cancelled out from, the image signal voltage, the resultant voltage being applied across the display material
Inventors
- 👤 Etsuya Takeda
- 👤 Yutaka Nanno
- 👤 Seiichi Nagata
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 19:14
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3648; G09G3/3655; G09G3/3659; G09G2300/00; G09G2300/08; G09G2300/0876; G09G2310/00; G09G2310/06; G09G2320/00; G09G2320/02; G09G2320/0204; G09G2320/0219; G09G2320/0247; G09G2320/0257
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
140 words
A method of driving a display unit having matrix-arranged pixel electrodes (A) each connected via a capacitor (8) to a first line, each pixel electrode being connected to a switching element (3) which is electrically connected to an image signal line (6) and scan signal line (1), and display material held between said pixel electrode and opposing electrode and being AC driven, wherein an image signal voltage (Vsig) is transmitted to said pixel electrode during an on-period of said switching element, and a modulating signal (Ve) with its voltage reversing alternately for each field is applied to said first line during an off-period of said switching element, thereby changing the potential of said pixel electrode so that said changed potential is superposed upon, or cancelled out from, said image signal voltage, the resultant voltage being applied across said display material.
Claim 2
Independent Claim
140 words
A method of driving a display unit having matrix-arranged pixel electrodes (A) each connected via a capacitor (8) to a first line, each pixel electrode being connected to a switching element (3) which is electrically connected to an image signal line (6) and scan signal line (1), and display material held between said pixel electrode and opposing electrode and being AC driven, wherein an image signal voltage (Vsig) is transmitted to said pixel electrode during an on-period of said switching element, and a modulating signal (Ve) with its voltage reversing alternately for each field is applied to said first line during an off-period of said switching element, thereby changing the potential of said pixel electrode so that said changed potential is superposed upon, or cancelled out from, said image signal voltage, the resultant voltage being applied across said display material.
Claim 3
Dependent Claim
60 words
A method of driving a display unit according to claim 1, wherein the polarity of said image signal voltage transmitted during the on-period of said switching element is reversed alternately for each scan line, and the polarity of said modulating signal applied to said first line during the off-period of said switching element is reversed alternately for each scan line.
Claim 4
Dependent Claim
45 words
A method of driving a display unit according to claim 2, wherein the absolute values of Ve(+) and VE(-) of said modulating signal with its polarity reversed, are different, said modulating signal being applied to said first line during the off-period of said switching element.
Claim 5
Dependent Claim
33 words
A method of driving a display unit according to claim 3, wherein a part of the potential of said modulating signal is changed before the end of the off-period of said switching element.
Claim 6
Independent Claim
82 words
A method of driving a display unit according to anyone of claims 1 to 4,wherein said switching element is a thin film transistor (TFT) and a relationship between Ve(+) and Ve(-) of said modulating signal with its polarity reversing alternately for each scan line and a scan signal voltage Vg is given by: CsVe(+) + CgdVg = CsVe(-) - CgdVg where Cs is a storage capacitor, Cgd is a gate-drain capacitor and Csd is a source-drain capacitor of said thin film transistor.
Claim 7
Independent Claim
36 words
A method of driving a display unit according to anyone of claims 1 to 5, wherein the potential of said opposing electrode of the liquid crystal display unit is constant at least during each field period.
Claim 8
Independent Claim
42 words
A method of driving a display unit according to anyone of claims 1 to 5, wherein the potential of said opposing electrode of the liquid crystal display unit is constant and equal to the average center potential of said image signal voltages.
Claim 9
Independent Claim
25 words
A method of driving a display unit according to anyone of claims 1 to 5,wherein the potential of said opposing electrode is electrically made floated.
Claim 10
Independent Claim
44 words
A method of driving a display unit according to anyone of claims 1 to 8, wherein said first line is used in common with said scan signal line, and said modulating signal is applied to said scan signal line superposing upon said scan signal.
Claim 11
Independent Claim
46 words
A method of driving a display unit according to anyone of claims 1 to 9, wherein the average DC voltage among said opposing electrode, image signal line and pixel electrode is smaller than CgdVg/Σ C, where Σ C is the total electrostatic capacitance per one pixel.
Claim 12
Independent Claim
100 words
A method of driving a display unit according to anyone of claims 1 to 10, wherein Ve(+) and VE(-) of said modulating signal voltage are set so as to satisfy the following formula: Vth ≦ Δ V* ≦ Vmax where ΔV* is expressed by: ΔV* = (Ve(+) + Ve(-)) Cs/2Ct Ct = Cs + Cgd + Csd + Clc where the voltage range within which the transmission factor of a liquid crystal changes is from Vth to Vmax, Cs is the storage capacitor, Cgd is a gate-drain capacitor, Csd is a source-drain capacitor, and Clc is the liquid crystal capacitor.
Claim 13
Dependent Claim
27 words
A method of driving a display unit according to claim 11, wherein ΔV* is set so as to satisfy the following equation: ΔV* = (Vmax + Vth)/2
References Cited (Backward Citations)
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