# US 8,786,591 B2 · Pixel and organic light emitting display using the same

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

- Number: US 8,786,591 B2
- Document ID: US8786591B2
- Status: Granted
- Kind: B2
- Application number: 13/030,085
- Filed: 2011-02-17
- Published: 2012-02-16
- Granted: 2014-07-22
- Earliest claimed: 2010-08-11
- Assignees: Samsung Display Co., Ltd.
- Applicants: Yong-Sung Park; Deok-Young Choi; Ji-Hye Eom
- Inventors: Yong-Sung Park; Deok-Young Choi; Ji-Hye Eom
- Web page: https://patentgrep.com/patent/US8786591B2

## CPC

- G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element
- G09G 3/3291: in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
- G09G 2300/0465: Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
- G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing
- G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor
- G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
- G09G 2310/0251: Precharge or discharge of pixel before applying new pixel voltage
- G09G 2310/0262: The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
- G09G 2320/043: Preventing or counteracting the effects of ageing
- 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)

## Abstract

A pixel capable of reducing leakage current (to display an image with desired brightness) is provided. The pixel includes: an organic light emitting diode (OLED) coupled to a second power source; a first transistor for controlling an amount of current that flows from a first power source to the second power source via the OLED; a second transistor coupled between a data line and the first transistor, and configured to turn on when a scan signal is supplied to a scan line; a third transistor and a fourth transistor serially coupled between the first transistor and an initializing power source; and a fifth transistor coupled between a first node coupled to a gate electrode of the first transistor, and a second node that is a common node between the third transistor and the fourth transistor, and configured to turn off in a period where current is supplied to the OLED.

## Claims

### Claim 1

A pixel comprising:
an organic light emitting diode (OLED) comprising a cathode electrode coupled to a second power source;
a first transistor comprising a gate electrode coupled to and sharing a voltage of a first node for controlling an amount of current that flows from a first power source coupled to a first electrode of the first transistor, to the second power source via the OLED;
a second transistor coupled between a data line and the first electrode of the first transistor, and configured to turn on when a scan signal is supplied to an ith (i is a natural number) scan line;
a third transistor and a fourth transistor serially coupled between a second electrode of the first transistor and an initializing power source, a first electrode of the third transistor being coupled to the second electrode of the first transistor, a second node being a common node between the third transistor and the fourth transistor and sharing a common voltage between a second electrode of the third transistor and a first electrode of the fourth transistor; and
a fifth transistor coupled between the first node and the second node, and configured to electrically disconnect the first node from the second node in a period when the current is supplied to the OLED.

### Claim 2 (depends on 1)

The pixel as claimed in claim 1, wherein the third transistor is configured to turn on when the scan signal is supplied to the ith scan line.

### Claim 3 (depends on 1)

The pixel as claimed in claim 1, wherein the fourth transistor is configured to turn on when a scan signal is supplied to an (i-1)th scan line.

### Claim 4 (depends on 1)

The pixel as claimed in claim 1, wherein the fifth transistor is configured to be on whenever the third transistor or the fourth transistor is turned on, and is configured to be off in a period when the third transistor and the fourth transistor are turned off.

### Claim 5 (depends on 1)

The pixel as claimed in claim 1, further comprising a storage capacitor coupled between the first node and the first power source.

### Claim 6 (depends on 1)

The pixel as claimed in claim 1, further comprising:
a seventh transistor coupled between the first electrode of the first transistor and the first power source, and configured to be off when the fifth transistor is turned on; and
a sixth transistor coupled between the second electrode of the first transistor and the OLED, and configured to turn on and turn off concurrently with the seventh transistor.

### Claim 7 (depends on 6)

The pixel as claimed in claim 6, further comprising an eighth transistor coupled between the second node and a reference power source, and configured to turn on and turn off concurrently with the sixth transistor.

### Claim 8 (depends on 6)

The pixel as claimed in claim 6, further comprising an eighth transistor coupled between the second node and the data line, and configured to turn on and turn off concurrently with the sixth transistor.

### Claim 9 (depends on 6)

The pixel as claimed in claim 6, further comprising an eighth transistor coupled between the second node and a gate electrode of the fourth transistor, and configured to turn on and turn off concurrently with the sixth transistor.

### Claim 10 (depends on 1)

The pixel as claimed in claim 1, wherein the fifth transistor is formed by serially coupling a plurality of transistors.

### Claim 11

An organic light emitting display comprising:
a scan driver for supplying scan signals to scan lines, for supplying emission control signals to emission control lines, and for supplying inverted emission control signals to inverted emission control lines;
a data driver for supplying data signals to data lines; and
pixels located at crossing regions of the scan lines and the data lines,
wherein a pixel from among the pixels, positioned in an ith (i is a natural number) horizontal line, comprises:
an organic light emitting diode (OLED) comprising a cathode electrode coupled to a second power source;
a first transistor comprising a gate electrode coupled to and sharing a voltage of a first node for controlling an amount of current that flows from a first power source coupled to a first electrode of the first transistor, to the second power source via the OLED;
a second transistor coupled between one of the data lines and the first electrode of the first transistor, and configured to turn on when one of the scan signals is supplied to an ith scan line of the scan lines;
a third transistor comprising a first electrode coupled to a second electrode of the first transistor, and a second electrode coupled to and sharing a voltage of a second node, and configured to turn on when the one of the scan signals is supplied to the ith scan line;
a fourth transistor comprising a first electrode coupled to and sharing the voltage of the second nod; and a second electrode coupled to an initializing power source, and configured to turn on when another of the scan signals is supplied to an (i-1)th scan line of the scan lines; and
a fifth transistor coupled between the second node and the first node, and configured to electrically connect the first node to the second node when one of the inverted emission control signals is supplied to an ith inverted emission control line of the inverted emission control lines.

### Claim 12 (depends on 11)

The organic light emitting display as claimed in claim 11, wherein the initializing power source is configured to supply a lower voltage than the data signals.

### Claim 13 (depends on 11)

The organic light emitting display as claimed in claim 11, wherein the scan driver is configured to supply the one of the inverted emission control signals to the ith inverted emission control line to overlap the one of the scan signals and the other of the scan signals respectively supplied to the ith scan line and the (i-1)th scan line.

### Claim 14 (depends on 11)

The organic light emitting display as claimed in claim 11, further comprising a storage capacitor coupled between the gate electrode of the first transistor and the first power source.

### Claim 15 (depends on 11)

The organic light emitting display as claimed in claim 11, further comprising:
a seventh transistor coupled between the first electrode of the first transistor and the first power source, and configured to turn off when one of the emission control signals is supplied to an ith emission control line of the emission control lines; and
a sixth transistor coupled between the second electrode of the first transistor and the OLED, and configured to turn off when the one of the emission control signals is supplied to the ith emission control line.

### Claim 16 (depends on 15)

The organic light emitting display as claimed in claim 15, wherein the scan driver is configured to supply the one of the emission control signals to the ith emission control line whenever the one of the scan signals is supplied to the ith scan line or the other of the scan signals is supplied to the (i-1)th scan line.

### Claim 17 (depends on 15)

The organic light emitting display as claimed in claim 15, further comprising an eighth transistor coupled between the second node and a reference power source, and configured to turn on and turn off concurrently with the sixth transistor.

### Claim 18 (depends on 17)

The organic light emitting display as claimed in claim 17, wherein the reference power source is configured to supply a voltage that is not less than any of the data signals.

### Claim 19 (depends on 15)

The organic light emitting display as claimed in claim 15, further comprising an eighth transistor coupled between the second node and the one of the data lines, and configured to turn on and to turn off concurrently with the sixth transistor.

### Claim 20 (depends on 15)

The organic light emitting display as claimed in claim 15, further comprising an eighth transistor coupled between the second node and a gate electrode of the fourth transistor, and configured to turn on and turn off concurrently with the sixth transistor.

### Claim 21 (depends on 11)

The organic light emitting display as claimed in claim 11, wherein the fifth transistor is formed by serially coupling a plurality of transistors.