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EP0288011A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Liquid crystal display device and method of driving the same

Assignee: Hitachi Ltd
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Filing: 1988-04-19
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Granted: —
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Expires: 2008-04-19
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Abstract

Abstract A liquid crystal display panel and a method of driving the display panel are disclosed. The display panel and the driving method can reduce the leakage of a gate driving voltage to a first pixel electrode (9) due to the parasitic capacitance of a thin field transistor (4), and can lessen an adverse effect of noise which is generated at a second pixel electrode by cancelling out the capacitive coupling to the first pixel electrode, on an image displayed by the display panel.

Inventors

  • 👤 Toshihisa Tsukada
  • 👤 Yoshiyuki Kaneko
  • 👤 Akira Sasano

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 17:44
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/136213; G09G3/3611; G09G3/3648; G09G3/3659; G09G2300/00; G09G2300/04; G09G2300/0421; G09G2300/043; G09G2320/00; G09G2320/02; G09G2320/0204; G09G2320/0219; G09G2320/0247

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 240 words
A liquid crystal display panel including a first substrate, a second substrate having a transparent conduc­tive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, the liquid crystal display panel comprising: a capacitor (7) whose electrodes are formed of a portion of the pixel electrode (9) connected to a thin film transistor (4) which is driven by a gate line (2), and a portion of the next gate line (3); and gate voltage generating means (62, 72) for controlling the voltage of each gate line in such a manner that, when a gate driving voltage applied to a gate line (2) for driving a thin film transistor (4) is changed by an amount v₁ to turn off the thin film transistor, a voltage change (v₁ + v₂) in a gate driving voltage applied to the next gate line (3) is generated in a direc­tion opposite to the direction of the voltage change v₁ (where, v₁ > 0 and v₂ > 0).
Claim 2
Dependent Claim 240 words
A liquid crystal display panel including a first substrate, a second substrate having a transparent conduc­tive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, the liquid crystal display panel comprising: a capacitor (7) whose electrodes are formed of a portion of the pixel electrode (9) connected to a thin film transistor (4) which is driven by a gate line (2), and a portion of the next gate line (3); and gate voltage generating means (62, 72) for controlling the voltage of each gate line in such a manner that, when a gate driving voltage applied to a gate line (2) for driving a thin film transistor (4) is changed by an amount v₁ to turn off the thin film transistor, a voltage change (v₁ + v₂) in a gate driving voltage applied to the next gate line (3) is generated in a direc­tion opposite to the direction of the voltage change v₁ (where, v₁ > 0 and v₂ > 0).
Claim 3
Dependent Claim 242 words
A liquid crystal display panel including a first substrate, a second substrate having a transparent conduc­tive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving pixel electrode, the liquid crystal display panel comprising: a capacitor (7) whose electrodes are formed of a portion of the pixel electrode (9) connected to a thin film transistor (4) which is driven by the i-th gate line (2), and a portion of the (i+1)th gate line (3); and gate voltage generating means (62, 72) for controlling the voltage of each gate line in such a manner that, in synchronism with a voltage change v₁ in a gate driving voltage applied to the i-th gate line (2) for turning off a thin film transistor (4) driven by the i-th gate line, a voltage change (v₁ + v₂) in a gate driving voltage applied to the (i+1)th gate line (3) is generated in a direction opposite to the direction of the voltage change v₁ (where v₁ > 0 and v₂ > 0).
Claim 4
Dependent Claim 242 words
A liquid crystal display panel including a first substrate, a second substrate having a transparent conduc­tive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving pixel electrode, the liquid crystal display panel comprising: a capacitor (7) whose electrodes are formed of a portion of the pixel electrode (9) connected to a thin film transistor (4) which is driven by the i-th gate line (2), and a portion of the (i+1)th gate line (3); and gate voltage generating means (62, 72) for controlling the voltage of each gate line in such a manner that, in synchronism with a voltage change v₁ in a gate driving voltage applied to the i-th gate line (2) for turning off a thin film transistor (4) driven by the i-th gate line, a voltage change (v₁ + v₂) in a gate driving voltage applied to the (i+1)th gate line (3) is generated in a direction opposite to the direction of the voltage change v₁ (where v₁ > 0 and v₂ > 0).
Claim 5
Dependent Claim 162 words
A liquid crystal panel including a first sub­strate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, the liquid crystal display panel comprising means for applying each gate line with a gate driving voltage waveform capable of cancelling out the capacitive coupling to a first pixel electrode and reducing noise which is generated at a second pixel electrode by said cancellation of the capacitive coupling of the gate driving voltage to the first pixel electrode voltage.
Claim 6
Dependent Claim 162 words
A liquid crystal panel including a first sub­strate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first substrate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, the liquid crystal display panel comprising means for applying each gate line with a gate driving voltage waveform capable of cancelling out the capacitive coupling to a first pixel electrode and reducing noise which is generated at a second pixel electrode by said cancellation of the capacitive coupling of the gate driving voltage to the first pixel electrode voltage.
Claim 7
Independent Claim 229 words
A method of driving a liquid crystal display panel including a first substrate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first sub­strate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, and a plurality of capacitors (7) connected to the pixel electrodes, the electrodes of a capacitor (7) connected to a pixel electrode (9) driven by the i-th gate line (2) being formed of a portion of the pixel electrode and a portion of the (i+1)th gate line (3), wherein in synchronism with a voltage change v₁ in a gate driving voltage applied to the i-th gate line for turning off a thin film transistor (4) driven by the i-th gate line, a voltage change (v₁ + v₂) in a gate driving voltage applied to the ( i+1 )th gate line is generated in a direction opposite to the direction of the voltage change v₁ (where v₁ > 0 and v₂ > 0).
Claim 8
Independent Claim 229 words
A method of driving a liquid crystal display panel including a first substrate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first sub­strate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other, for driving a pixel electrode, and a plurality of capacitors (7) connected to the pixel electrodes, the electrodes of a capacitor (7) connected to a pixel electrode (9) driven by the i-th gate line (2) being formed of a portion of the pixel electrode and a portion of the (i+1)th gate line (3), wherein in synchronism with a voltage change v₁ in a gate driving voltage applied to the i-th gate line for turning off a thin film transistor (4) driven by the i-th gate line, a voltage change (v₁ + v₂) in a gate driving voltage applied to the ( i+1 )th gate line is generated in a direction opposite to the direction of the voltage change v₁ (where v₁ > 0 and v₂ > 0).
Claim 9
Dependent Claim 48 words
The invention as claimed in Claim 2 or 4, wherein the voltage change (v₁ + v₂) in the gate driving voltage ap­plied to the (i+1)th gate line (3) is generated simultaneously with the voltage change v₁ in the gate driving voltage ap­plied to the i-th gate line (2).
Claim 10
Dependent Claim 62 words
The invention as claimed in Claim 2 or 4, wherein the voltage (v₁ + v₂) in the gate driving voltage applied to the (i+1)th gate line (3) is generated when a time less than the selection time of the thin film transistor (4) has elapsed after the voltage change v₁ in the gate driving voltage ap­plied to the i-th gate line (2).
Claim 11
Dependent Claim 44 words
The invention as claimed in Claim 1, 2 or 4, wherein the capacitor C add of the capacitor (7) satisfies the following formula: C add ≒ (v₁/v₂) · C gs where C gs indicates the parasitic gate-source capacitance of the thin film transistor (4).
Claim 12
Independent Claim 161 words
A method of driving a liquid crystal display panel including a first substrate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first sub­strate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other for driving a pixel electrode, wherein each gate line is applied with a gate driving voltage waveform capable of cancelling out the capacitive coupling to a first pixel electrode and reducing noise which is generated at a second pixel electrode by said cancelling of the capacitive coupling of the gate driving voltage to the first pixel electrode voltage.
Claim 13
Independent Claim 161 words
A method of driving a liquid crystal display panel including a first substrate, a second substrate having a transparent conductive film (38) thereon, and a liquid crystal layer sandwiched between the first sub­strate and the second substrate, the first substrate having thereon a plurality of data lines (21), a plurality of gate lines (22), a plurality of pixel electrodes (9) each formed in the vicinity of a position where a data line and a gate line cross each other, and a plurality of thin film transistors (4) each formed at a position where a data line and a gate line cross each other for driving a pixel electrode, wherein each gate line is applied with a gate driving voltage waveform capable of cancelling out the capacitive coupling to a first pixel electrode and reducing noise which is generated at a second pixel electrode by said cancelling of the capacitive coupling of the gate driving voltage to the first pixel electrode voltage.

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