Liquid crystal device, liquid crystal device driving method, and electronic apparatus

Patent metadata

Field	Value
Publication number	US-9632338-B2
Application number	US-201514626876-A
Country	US
Kind code	B2
Filing date	Feb 19, 2015
Priority date	Mar 29, 2010
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

In a liquid crystal device according to the invention, a pre-tilt angle of a liquid crystal layer is greater on an opposing electrode side than on a pixel electrode side. A high potential and a low potential relative to an opposing electrode potential are alternately applied to pixel electrodes through switching elements; and the opposing electrode potential is higher than a standard potential, the standard potential being a potential in which the average potential between the high potential and the low potential has been shifted by an amount equivalent to the average value of the amount of change in the potential of the pixel electrodes caused by parasitic capacitance in the switching elements when the high potential is applied to the pixel electrodes and the amount of change in the potential of the pixel electrodes caused by parasitic capacitance when the low potential is applied to the pixel electrodes.

First claim

What is claimed is:

1. A method of driving a liquid crystal device, wherein
the liquid crystal device includes
an element substrate having multiple scanning lines, multiple data lines, switching elements, and pixel electrodes provided in correspondence to intersections between the scanning lines and the data lines,
an opposing substrate disposed opposing the element substrate that includes an opposing electrode,
a liquid crystal layer held between the element substrate and the opposing substrate,
a first orientation film provided on the side of the element substrate that faces the liquid crystal layer, and
a second orientation film provided on the side of the opposing substrate that faces the liquid crystal layer, with a first pre-tilt angle in the first orientation film set to be smaller than a second pre-tilt angle in the second orientation film, and

the method comprises:
applying an opposing electrode potential set so as to reduce flicker caused by parasitic capacitance in the switching elements to the opposing electrode;
applying a positive polarity voltage and a negative polarity voltage alternately to the pixel electrodes, the positive polarity voltage being a high voltage relative to the opposing electrode potential and the negative polarity voltage being a low voltage relative to the opposing electrode potential; and
setting, in a predetermined interval made up of a first interval in which the positive polarity voltage is applied and a second interval in which the negative polarity voltage is applied, a length of the first interval to be shorter than a length of the second interval.

2. The method according to claim 1 , wherein a ratio between the length of the second interval and the length of the first interval is set to a range that is greater than 50.0/50.0 and less than or equal to 52.0/48.0 when the first pre-tilt angle is set so as to be 6° less than the second pre-tilt angle.

3. The method according to claim 1 , wherein the pixel electrodes are configured of aluminum, and the opposing electrode is configured of indium tin oxide.

4. A method of driving a liquid crystal device, wherein
the liquid crystal device includes
an element substrate having a pixel electrode,
an opposing substrate disposed opposing the element substrate and including an opposing electrode,
a liquid crystal layer held between the element substrate and the opposing substrate,
a first orientation film provided between the element substrate and the liquid crystal layer, and
a second orientation film provided between the opposing substrate and the liquid crystal layer,
wherein the first orientation film is configured to form a first pre-tilt angle that is an angle between the director of the liquid crystal layer at the first orientation film and the thickness direction of the liquid crystal layer,
the second orientation film is configured to form a second pre-tilt angle that is an angle between the director of the liquid crystal layer at the second orientation film and the thickness direction of the liquid crystal layer, and
the first pre-tilt angle is smaller than a second pre-tilt angle, and

the method comprises:
applying an opposing electrode potential set so as to reduce flicker caused by parasitic capacitance to the opposing electrode;
applying a positive polarity voltage and a negative polarity voltage alternately to the pixel electrode, the positive polarity voltage being a high voltage relative to the opposing electrode potential and the negative polarity voltage being a low voltage relative to the opposing electrode potential; and
setting, in a predetermined interval made up of a first interval in which the positive polarity voltage is applied and a second interval in which the negative polarity voltage is applied, a length of the first interval to be shorter than a length of the second interval.

5. An electronic apparatus, comprising:
a liquid crystal device, and
a processing circuit configured to drive the liquid crystal device,

wherein
the liquid crystal device includes:
an element substrate having multiple scanning lines, multiple data lines, switching elements, and pixel electrodes provided in correspondence to intersections between the scanning lines and the data lines,
an opposing substrate disposed opposing the element substrate that includes an opposing electrode,
a liquid crystal layer held between the element substrate and the opposing substrate,
a first orientation film provided on the side of the element substrate that faces the liquid crystal layer, and
a second orientation film provided on the side of the opposing substrate that faces the liquid crystal layer, with a first pre-tilt angle in the first orientation film set to be smaller than a second pre-tilt angle in the second orientation film, and

the processing circuit is configured to drive the liquid crystal device by:
applying an opposing electrode potential set so as to reduce flicker caused by parasitic capacitance in the switching elements to the opposing electrode;
applying a positive polarity voltage and a negative polarity voltage alternately to the pixel electrodes, the positive polarity voltage being a high voltage relative to the opposing electrode potential and the negative polarity voltage being a low voltage relative to the opposing electrode potential; and
setting, in a predetermined interval made up of a first interval in which the positive polarity voltage is applied and a second interval in which the negative polarity voltage is applied, a length of the first interval to be shorter than a length of the second interval.

Assignees

• Seiko Epson Corp

Inventors

• Nishida Masakazu
• Yoshida Shohei
• Hirota Takenori
• Umeno Tomokazu
• Masuzawa Akinori

Classifications

• G02F1/1337

  Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers · CPC title

• G09G2310/0205

  Simultaneous scanning of several lines in flat panels · CPC title

• G02F1/136213

  Storage capacitors associated with the pixel electrode · CPC title

• G09G2300/0876

  Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes · CPC title

• G09G2310/0218

  with collection of electrodes in groups for n-dimensional addressing · CPC title