Data driver, organic light emitting display device using the same, and method of driving the organic light emitting display device

Patent metadata

Field	Value
Publication number	US-9812065-B2
Application number	US-201414150614-A
Country	US
Kind code	B2
Filing date	Jan 8, 2014
Priority date	Aug 10, 2005
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A data driver capable of displaying images with a substantially uniform brightness, an organic light emitting display device using the same, and a method of driving the organic light emitting display device. The data driver includes a plurality of current sink units for controlling predetermined currents to flow through data lines, a plurality of voltage generators for resetting values of gray scale voltages using compensation voltages generated when the predetermined currents flow, a plurality of digital-to-analog converters for selecting one gray scale voltage among the gray scale voltages as a data signal in response to bit values of the data supplied from the outside, and a plurality of switching units for supplying the data signal to the data lines. The predetermined currents may be set equal to pixel currents that correspond to a maximum brightness.

First claim

What is claimed is:

1. An organic light emitting display device comprising:
a display region including a plurality of pixels coupled to scan lines, data lines, and emission control lines;
a scan driver for supplying scan signals to the scan lines and for supplying emission control signals to the emission control lines; and
at least one data driver for supplying predetermined currents to the data lines in a first period of each horizontal period to generate compensation voltages, for resetting values of gray scale voltages with reset values using the compensation voltages, and for generating data signals using the reset values of the gray scale voltages,
wherein a pixel from among the pixels is coupled to a current scan line and a previous scan line among the scan lines and a data line among the data lines, and the pixel comprises:
a first power source;
an organic light emitting diode for receiving a pixel current from the first power source;
a first transistor and a second transistor each having a first electrode coupled to the data line and turned on when one of the scan signals is supplied to the current scan line;
a third transistor coupled between a second electrode of the first transistor and a reference power source and turned on when another one of the scan signals is supplied to the previous scan line;
a fourth transistor for controlling the pixel current received by the organic light emitting diode having a first electrode coupled to the first power source; and
a fifth transistor coupled between a gate electrode and a second electrode of the fourth transistor and turned on when said another one of the scan signals is supplied to the previous scan line, when turned on, the fifth transistor conducting current to the fourth transistor so that the fourth transistor operates as a diode, and

wherein the data driver comprises:
a plurality of current sink units receiving the predetermined currents from the pixels in the first period of each horizontal period;
a plurality of voltage generators for resetting the values of the gray scale voltages using the compensation voltages generated when the predetermined currents flow;
a plurality of digital-to-analog converters for selecting one gray scale voltage among the gray scale voltages as a data signal in response to bit values of data supplied from an outside; and
a plurality of switching units for supplying the data signals to the data lines in a second period excluding the first period of each horizontal period.

2. The organic light emitting display device as claimed in claim 1 , wherein the pixel further comprises:
a first capacitor coupled between the second electrode of the first transistor and the first power source; and
a second capacitor coupled between the second electrode of the first transistor and a gate electrode of the fourth transistor.

3. The organic light emitting display device as claimed in claim 1 , wherein the pixel further comprises:
a first capacitor coupled between a gate electrode of the fourth transistor and the first power source; and
a second capacitor coupled between the second electrode of the first transistor and the gate electrode of the fourth transistor.

4. The organic light emitting display device as claimed in claim 1 , wherein the pixel further comprises a sixth transistor coupled between the second electrode of the fourth transistor and the organic light emitting diode, the sixth transistor being turned off when a respective one of the emission control signals is supplied, and turned on otherwise.

5. The organic light emitting display device as claimed in claim 1 , wherein each of the current sink units receives a maximum current that can be supplied by the pixel to the organic light emitting diode.

6. The organic light emitting display device as claimed in claim 1 , wherein each of the current sink units comprises:
a current source for receiving the predetermined currents;
a sixth transistor located between the data line and one of the voltage generators to be turned on in the first period;
a seventh transistor located between the data line and the current source to be turned on in the first period; and
a capacitor for being charged with one of the compensation voltages applied to the sixth transistor when one of the predetermined currents flows through the data line.

7. The organic light emitting display device as claimed in claim 1 , wherein each of the switching units comprises at least one transistor being turned on in the second period.

8. The organic light emitting display device as claimed in claim 7 ,
wherein each of the switching units comprises two transistors, and
wherein the two transistors are coupled to each other in a form of a transmission gate.

9. The organic light emitting display device as claimed in claim 1 , wherein each of the voltage generators comprises a plurality of voltage dividing resistors coupled between a first terminal and a second terminal in order to generate the gray scale voltages.

10. The organic light emitting display device as claimed in claim 9 ,
wherein the first terminal receives a reference power, and
wherein the second terminal receives one of the compensation voltages.

11. The data driver as claimed in claim 1 , further comprising:
first buffers located between the digital-to-analog converters and the switching units; and
second buffers located between the current sink units and the voltage generators.

12. The organic light emitting display device as claimed in claim 1 , further comprising at least one precharging unit for supplying precharging voltages to pixels coupled to the data lines in a 0 th period before the first period.

Assignees

• Samsung Display Co Ltd
• Iucf-Hyu (Industry-University Coop Found Hanyang University)
• Industry-Univ Coop Found Hanyang Univ

Inventors

• Ryu Do Hyung
• Chung Bo Yong
• Kim Hong Kwon
• Kwon Oh Kyong

Classifications

• G09G2310/0251

  Precharge or discharge of pixel before applying new pixel voltage · CPC title

• G09G2320/0276

  for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction · CPC title

• G09G3/3291 Primary

  in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements · CPC title

• G09G2300/0819

  used for counteracting undesired variations, e.g. feedback or autozeroing · CPC title

• G09G2300/0861

  with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes · CPC title