# US 7,078,864 B2 · Display apparatus and power supply device for displaying

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,078,864 B2
- Document ID: US7078864B2
- Status: Granted
- Kind: B2
- Application number: 10/832,296
- Filed: 2004-04-27
- Published: 2004-10-21
- Granted: 2006-07-18
- Earliest claimed: 2001-06-07
- Assignees: Hitachi, Ltd.
- Inventors: Yasuyuki Kudo; Akihito Akai; Kazuo Ookado; Kazunari Kurokawa; Atsuhiro Higa
- Web page: https://patentgrep.com/patent/US7078864B2

## CPC

- G06F 1/3265: {Power saving in display device}
- G06F 1/3203: Power management, i.e. event-based initiation of a power-saving mode
- G09G 3/3614: {Control of polarity reversal in general}
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 3/3655: {Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors}
- G09G 3/3696: {Generation of voltages supplied to electrode drivers}
- G09G 2330/02: Details of power systems and of start or stop of display operation
- G09G 2330/021: Power management, e.g. power saving
- Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

A power supply device for displaying includes a set register for setting an amplitude and voltage level of a driving voltage for a common electrode and an amplitude and voltage level of a non-selecting period voltage for a scan line, an amplitude reference generating circuit for generating an amplitude reference voltage for the driving voltage of the common electrode and for the non-selecting period voltage of the scan line according to a set value, a VcomH reference generating circuit and a VcomL generating circuit for A.C. driving the common electrode with an amplitude and voltage level determined by the amplitude reference voltage and set value, a VgoffH generating circuit and a VgoffL reference generating circuit for generating the non-selecting period voltage of the scan line with an amplitude and voltage level determined by the amplitude reference voltage and set value.

## Claims

### Claim 1

A display apparatus comprising:
a display panel having a plurality of pixel parts arranged in a matrix, each pixel part including a pixel electrode connected to a data line and a scan line, and a common electrode opposed to said pixel electrode;
a data driver for applying a gray scale voltage corresponding to display data to the pixel electrode of the pixel part, via the data line;
a gate driver for applying a gate-on voltage and a gate-off voltage to the pixel electrode of the pixel part, via the scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate-on voltage and the gate-off voltage, and a common voltage for the common electrode,
wherein the power supply device includes a holding circuit for holding an electric charge corresponding to the common voltage, and the gate-off voltage is generated from the electric charge held in the holding circuit.

### Claim 2 (depends on 1)

A display apparatus according to claim 1, wherein the power supply device further comprises:
a first generating circuit for generating the common voltage; and
a second generating circuit for generating the gate-off voltage from the electric charge held in the holding circuit.

### Claim 3 (depends on 2)

A display apparatus according to claim 2, wherein the power supply device further comprises:
a voltage switching circuit for switching connection of the holding circuit between the first generating circuit and the second generating circuit.

### Claim 4 (depends on 3)

A display apparatus according to claim 3, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage,
a first switching circuit provided to switch between the first common voltage and the second common voltage to output a selected common voltage; and a second switching circuit provided to switch between the first gate-off voltage and the second gate-off voltage to output a selected gate-off voltage; the second switching circuit selecting the first gate-off voltage when the first switching circuit selects the first common voltage, and selecting the second gate-off voltage when the first switching circuit selects the second common voltage.

### Claim 5 (depends on 4)

A display apparatus according to claim 4, wherein the voltage switching circuit the holding circuit with the first generating circuit, when the first switching circuit selects the first common voltage, and connects the holding circuit with the second generating circuit when the first switching circuit selects the second common voltage.

### Claim 6 (depends on 1)

A display apparatus according to claim 1, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage, and
the holding circuits holds an electric charge corresponding to a voltage difference between the first common voltage and the second common voltage as the electric charge corresponding to the common voltage.

### Claim 7

A display apparatus comprising:
a display panel having a plurality of pixel parts arranged in a matrix, each pixel part including a pixel electrode connected to a data line and a scan line, and a common electrode opposed to the pixel electrode;
a data driver for applying a gray scale voltage corresponding to display data to the pixel electrode of the pixel part, via the data line;
a gate driver for applying a gate-on voltage and a gate-off voltage to the pixel electrode of the pixel part, via the scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate-on voltage and the gate-off voltage, and a common voltage for the common electrode,
wherein the power supply device includes a capacitor for holding an electric charge corresponding to the common voltage, and a selector for selecting between the charge of the capacitor and the discharge of the capacitor depending on a polarity of the pixel part.

### Claim 8 (depends on 7)

A display apparatus according to claim 7, wherein the selector selects between the charge of the capacitor and the discharge of the capacitor according to an alternative current signal for changing the polarity of the pixel part.

### Claim 9 (depends on 7)

A display apparatus according to claim 7, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage, and
the selector selects the charge of the capacitor when the power supply device outputs the first common voltage and the first gate-off voltage, and selects the discharge of the capacitor when the power supply device outputs the second common voltage and the second gate-off voltage.

### Claim 10

A display apparatus comprising:
a display panel having a plurality of pixel parts arranged in a matrix, each pixel part including a pixel electrode connected to a data line and a scan line, and a common electrode opposed to the pixel electrode;
a data driver for applying a gray scale voltage corresponding to display data to the pixel electrode of the pixel part, via the data line;
a gate driver for applying a gate voltage for scanning the pixel parts, to the pixel electrode of the pixel part, via the scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate voltage, and a common voltage for the common electrode,
wherein the power supply device includes a capacitor for holding an electric charge corresponding to the common voltage, and the gate voltage is generated from the common voltage held in the capacitor.

### Claim 11 (depends on 10)

A display apparatus according to claim 10, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate voltage and a second gate voltage different from the first gate-off voltage, and
the capacitor is charged by the common voltage when the power supply device outputs the first common voltage and the first gate-off voltage, and is discharged by the gate-off voltage when the power supply device outputs the second common voltage and the second gate-off voltage.

### Claim 12

A display apparatus comprising:
a display panel;
a data driver for applying a gray scale voltage corresponding to display data to the display panel, via a data line;
a gate driver for applying a gate-on voltage and a gate-off voltage to the display panel via a scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate-on voltage and the gate-off voltage, and a common voltage for a common electrode,
wherein the power supply device includes a holding circuit for holding an electric charge corresponding to the common voltage, and the gate-off voltage is generated from the electric charge held in the holding circuit.

### Claim 13 (depends on 12)

A display apparatus according to claim 12, wherein the power supply device further comprises:
a first generating circuit for generating the common voltage; and
a second generating circuit for generating the gate-off voltage from the electric charge held in the holding circuit.

### Claim 14 (depends on 13)

A display apparatus according to claim 13, wherein the power supply device further comprises:
a voltage switching circuit for switching connection of the holding circuit between the first generating circuit and the second generating circuit.

### Claim 15 (depends on 14)

A display apparatus according to claim 14, wherein: the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage,
a first switching circuit provided to switch between the first common voltage and the second common voltage to output a selected common voltage; and a second switching circuit provided to switch between the first gate-off voltage and the second gate-off voltage to output a selected gate-off voltage; the second switching circuit selecting the first gate-off voltage when the first switching circuit selects the first common voltage, and selecting the second gate-off voltage when the first switching circuit selects the second common voltage.

### Claim 16 (depends on 15)

A display apparatus according to claim 15, wherein the voltage switching circuit the holding circuit with the first generating circuit, when the first switching circuit selects the first common voltage, and connects the holding circuit with the second generating circuit when the first switching circuit selects the second common voltage.

### Claim 17 (depends on 12)

A display apparatus according to claim 12, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage, and
the holding circuits holds an electric charge corresponding to a voltage difference between the first common voltage and the second common voltage as the electric charge corresponding to the common voltage.

### Claim 18

A display apparatus comprising:
a display panel;
a data driver for applying a gray scale voltage corresponding to display data to the display panel, via a data line;
a gate driver for applying a gate-on voltage and a gate-off voltage to the display panel, via a scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate-on voltage and the gate-off voltage, and a common voltage for a common electrode,
wherein the power supply device includes a capacitor for holding an electric charge corresponding to the common voltage, and a selector for selecting between the charge of the capacitor and the discharge of the capacitor depending on a polarity of the display panel.

### Claim 19 (depends on 18)

A display apparatus according to claim 18, wherein the selector selects between the charge of the capacitor and the discharge of the capacitor according to an alternative current signal for changing the polarity of the display panel.

### Claim 20 (depends on 18)

A display apparatus according to claim 18, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate-off voltage and a second gate-off voltage different from the first gate-off voltage, and
the selector selects the charge of the capacitor when the power supply device outputs the first common voltage and the first gate-off voltage, and selects the discharge of the capacitor when the power supply device outputs the second common voltage and the second gate-off voltage.

### Claim 21

A display apparatus comprising:
a display panel;
a data driver for applying a gray scale voltage corresponding to display data to the display panel, via a data line;
a gate driver for applying a gate voltage, to the display panel, via a scan line; and
a power supply device for generating a reference voltage for the gray scale voltage, the gate voltage, and a common voltage for a common electrode,
wherein the power supply device includes a capacitor for holding an electric charge corresponding to the common voltage, and the gate voltage is generated from the common voltage held in the capacitor.

### Claim 22 (depends on 21)

A display apparatus according to claim 21, wherein:
the common voltage includes a first common voltage and a second common voltage different from the first common voltage,
the gate-off voltage includes a first gate voltage and a second gate voltage different from the first gate-off voltage, and
the capacitor is charged by the common voltage when the power supply device outputs the first common voltage and the first gate-off voltage, and is discharged by the gate-off voltage when the power supply device outputs the second common voltage and the second gate-off voltage.