LIQUID CRYSTAL DEVICE, METHOD OF DRIVING LIQUID CRYSTAL DEVICE AND ELECTRONIC APPARATUS

• US 20080218650A1
• Filed: 02/21/2008
• Published: 09/11/2008
• Est. Priority Date: 03/06/2007
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: UTSUNOMIYA, Sumio, KOSHIHARA, Takeshi
• Application Number:
  US12/035,140
• Publication Number:
  US 20080218650A1
• Time in Patent Office: Days
• US Class Current: 349/39
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G09G 2300/0876 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 Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal device includes a first substrate, a second substrate, liquid crystal, a detection electrode, a liquid crystal capacitor, a storage capacitor, a switching element, a selection circuit, a signal supplying circuit, and an electric potential control circuit. The first substrate is opposed to the second substrate. The liquid crystal is sealed in a gap between the first substrate and the second substrate. The detection electrode is provided on a side of the first substrate, opposite to a side on which the liquid crystal is provided. The detection electrode detects a contact on the basis of variation in capacitance. The liquid crystal capacitor includes a pixel electrode, an opposite electrode, and the liquid crystal between the pixel electrode and the opposite electrode. The storage capacitor includes a first electrode and a second electrode that is connected to the pixel electrode. The switching element is connected between the pixel electrode and a signal line. The selection circuit conducts the switching element during a selection period and interrupts conduction of the switching element after the selection period has elapsed. The signal supplying circuit supplies a data electric potential (for example, an electric potential VDP or an electric potential VDN shown in FIG. 4) corresponding to positive polarity writing or negative polarity writing to the signal line during the selection period. The electric potential control circuit shifts an electric potential of the first electrode to a high level side after a selection period in which a data electric potential corresponding to the positive polarity writing is supplied to the signal line has elapsed, and shifts an electric potential of the first electrode to a low level side after a selection period in which a data electric potential corresponding to the negative polarity writing is supplied to the signal line has elapsed.

Claims

1. A liquid crystal device comprising:

a first substrate;

a second substrate that is opposed to the first substrate;

liquid crystal that is sealed in a gap between the first substrate and the second substrate;

a detection electrode that is provided on a side of the first substrate, opposite to a side on which the liquid crystal is provided, wherein the detection electrode detects a contact on the basis of variation in capacitance;

a liquid crystal capacitor that includes a pixel electrode, an opposite electrode, and the liquid crystal between the pixel electrode and the opposite electrode;

a storage capacitor that includes a first electrode and a second electrode that is connected to the pixel electrode;

a switching element that is connected between the pixel electrode and a signal line;

a selection circuit that conducts the switching element during a selection period and interrupts conduction of the switching element after the selection period has elapsed;

a signal supplying circuit that supplies a data electric potential corresponding to positive polarity writing or negative polarity writing to the signal line during the selection period; and

an electric potential control circuit that shifts an electric potential of the first electrode to a high level side after a selection period in which a data electric potential corresponding to the positive polarity writing is supplied to the signal line has elapsed, and that shifts an electric potential of the first electrode to a low level side after a selection period in which a data electric potential corresponding to the negative polarity writing is supplied to the signal line has elapsed.

2. The liquid crystal device according to claim 1, wherein the detection electrode is formed on a surface of the first substrate, which is opposite to a surface on which the liquid crystal is provided.

3. The liquid crystal device according to claim 1, wherein the pixel electrode is formed on a surface of the second substrate, which is opposite to the first substrate, and wherein the opposite electrode is formed between the pixel electrode and the first substrate and maintained at a constant electric potential.

4. An electronic apparatus comprising the liquid crystal device according to claim 1.

5. A method of driving a liquid crystal device that includes a first substrate, a second substrate opposed to the first substrate, liquid crystal sealed in a gap between the first substrate and the second substrate, a liquid crystal capacitor that has a pixel electrode, an opposite electrode and the liquid crystal between the pixel electrode and the opposite electrode, a storage capacitor that has a first electrode and a second electrode connected to the pixel electrode, and a detection electrode formed on a side of the first substrate, opposite to a side on which the liquid crystal is provided, wherein the detection electrode is used for detecting a contact on the basis of variation in capacitance, the method comprising:

connecting the pixel electrode and the signal line during a selection period and interrupting the pixel electrode from the signal line after the selection period has elapsed;

supplying the signal line during the selection period with a data electric potential corresponding to positive polarity writing or negative polarity writing; and

shifting an electric potential of the first electrode to a high level side after a selection period in which a data electric potential corresponding to the positive polarity writing is supplied to the signal line has elapsed and shifting an electric potential of the first electrode to a low level side after a selection period in which a data electric potential corresponding to the negative polarity writing is supplied to the signal line has elapsed.