ORGANIC LIGHT EMITTING DISPLAY AND METHOD OF DRIVING THE SAME

• US 20100013824A1
• Filed: 06/01/2009
• Published: 01/21/2010
• Est. Priority Date: 07/16/2008
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Jeong, Jin-Tae, Eom, Ki-Myeong, Jeong, Seon-I, Kim, Mi-Hae
• Granted Patent: US 8,482,492 B2
• Time in Patent Office: Days
• US Class Current: 345/214
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: 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
• CPC Class Codes: G09G 2310/0245 Clearing or presetting the whole screen independently of waveforms, e.g. on power-on G09G2310/063 takes precedence
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G11C 19/184 with field-effect transistors, e.g. MOS-FET
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence

Abstract

An organic light emitting display capable of preventing erroneous emission from being generated at the initial stage of driving the organic light emitting display and a method of driving the same. The organic light emitting display includes a display unit including data lines, scan lines, emission control lines, and pixels coupled to the data lines, the scan lines, and the emission control lines. A data driver is coupled to the data lines for transmitting data signals. A scan driver is coupled to the scan lines for transmitting scan signals. An emission control driver is coupled to the emission control lines for transmitting emission control signals. A controller is provided for transmitting a plurality of control signals for controlling the data driver, the scan driver, and the emission control driver, and outputting a first control signal for preventing currents from flowing to organic light emitting diodes of the pixels.

Claims

1. An organic light emitting display comprising:

a display unit comprising data lines, scan lines, emission control lines, and a plurality of pixels coupled to the data lines, the scan lines, and the emission control lines;

a data driver coupled to the data lines for transmitting data signals;

a scan driver coupled to the scan lines for transmitting scan signals;

an emission control driver coupled to the emission control lines for transmitting emission control signals; and

a controller for transmitting a plurality of control signals for controlling the data driver, the scan driver, and the emission control driver, and outputting a first control signal to prevent currents from flowing to organic light emitting diodes of the pixels.

2. The organic light emitting display as claimed in claim 1, wherein the emission control driver further comprises a switch for outputting a voltage of a first power source to an output end of the emission control driver for outputting the emission control signals in response to the first control signal.

3. The organic light emitting display as claimed in claim 1,

wherein the emission control driver comprises a plurality of stages, and

wherein a stage of the plurality of stages comprises:

a first signal processor for receiving a start pulse or a shift signal output from a previous stage, a first clock, and a sub-signal of the first clock to output a first voltage from a first power source or a second power source;

a second signal processor for receiving the first voltage and outputting a second voltage that is an inverted voltage of the first voltage;

a third signal processor for receiving the second voltage and outputting a third voltage that is an inverted voltage of the second voltage, and generating a shift signal that is transmitted to a subsequent stage of the plurality of stages;

a fourth signal processor for receiving the third voltage and outputting a fourth voltage that is an inverted voltage of the third voltage; and

a switch for performing switching between the first power source and an output end of the stage in response to the first control signal.

4. The organic light emitting display as claimed in claim 3,

wherein the first signal processor comprises a first transistor, a second transistor, a third transistor, and a first capacitor,

wherein the first transistor has a source for receiving a first power source, a drain coupled to a second node, and a gate for receiving the first clock,

wherein the second transistor has a source coupled to the second node, a drain for receiving a first sub-clock, and a gate coupled to a first node,

wherein the third transistor has a source for receiving a start pulse or a first shift signal output from a previous stage, a drain coupled to the first node, and a gate for receiving the first clock, and

wherein the first capacitor is coupled between the first node and the second node.

5. The organic light emitting display as claimed in claim 3,

wherein the second signal processor comprises a fourth transistor, a fifth transistor, and a sixth transistor,

wherein the fourth transistor has a source coupled to the first power source, a drain coupled to a source of the fifth transistor, and a gate for receiving an output voltage of the first signal processor,

wherein the fifth transistor has its source coupled to the drain of the fourth transistor, a drain coupled to a third node, and a gate for receiving the output voltage of the first signal processor, and

wherein the sixth transistor has a source coupled to the third node, a drain coupled to the second power source, and a gate for receiving the first clock.

6. The organic light emitting display as claimed in claim 3,

wherein the third signal processor comprises a seventh transistor and an eighth transistor,

wherein the seventh transistor has a source coupled to the first power source, a drain coupled to a fourth node, and a gate for receiving an output signal of the second signal processor to output the first shift signal, and

wherein the eighth transistor has a source coupled to the fourth node, a drain coupled to the second power source, and a gate for receiving an output voltage of the first signal processor.

7. The organic light emitting display as claimed in claim 3, wherein the fourth signal processor comprises:

a ninth transistor having a source coupled to the first power source, a drain coupled to the output end of the stage, and a gate for receiving an output signal of the third signal processor;

a tenth transistor having a source coupled to the output end of the stage, a drain coupled to the second power source, and a gate for receiving an output signal of the second signal processor; and

a second capacitor coupled between the output end of the stage and the gate of the tenth transistor.

8. The organic light emitting display as claimed in claim 1, wherein each of the pixels comprises:

an organic light emitting diode (OLED) for emitting light in response to a driving current flowing from a pixel power source to a base power source;

a first transistor for generating the driving current in response to the data signals;

a second transistor for transmitting the data signals to the gate of the first transistor in response to the scan signals;

a third transistor for switching the flow of the driving current in response to the emission control signals; and

a capacitor for maintaining a gate voltage of the first transistor.

9. A method of driving an organic light emitting display comprising an emission control driver and pixels having transistors for switching driving currents in response to emission control signals, each of the pixels having an organic light emitting diode (OLED) for receiving a corresponding one of the driving currents in response to the switching operations of the transistors, the method comprising:

receiving a first control signal for a time duration in which a voltage for turning off the transistors is output from the emission control driver; and

receiving a start signal and clocks by the emission control driver to generate the emission control signals subsequent to the time duration.

10. The method as claimed in claim 9,

wherein, after the first control signal is transmitted, voltages of a pixel power source and a base power source are transmitted to the pixels, and

wherein, when at least one frame elapses after the voltages of the pixel power source and the base power source are transmitted, a scan driver operates.

11. The method as claimed in claim 10, wherein a data driver of the organic light emitting display is configured to generate and transmit a black data signal to the pixels from a point in time in which the voltages of the pixel power source and the base power source begin to be transmitted to the pixels to a point in time after the emission control driver generates emission control signals.

12. An organic light emitting display comprising:

a display unit comprising data lines, scan lines, emission control lines, and a plurality of pixels coupled to the data lines, the scan lines, and the emission control lines;

a data driver coupled to the data lines for transmitting data signals;

a scan driver coupled to the scan lines for transmitting scan signals; and

an emission control driver coupled to the emission control lines for transmitting emission control signals,

wherein the emission control driver is configured to prevent the pixels from emitting during an initial period after power is supplied to the display unit, and

during the initial period, the data signals comprise data corresponding to black color.

13. The organic light emitting display as claimed in claim 12, further comprising a controller for outputting a first control signal to the emission control driver,

wherein the emission control driver is configured to prevent the pixels from emitting during the initial period in response to the first control signal.

14. The organic light emitting display as claimed in claim 13,

wherein the emission control driver comprises a plurality of stages, and

wherein a stage of the plurality of stages comprises:

a first signal processor for receiving a start pulse or a shift signal output from a previous stage, a first clock, and a sub-signal of the first clock to output a first voltage from a first power source or a second power source;

a second signal processor for receiving and inverting the first voltage to output a second voltage that is an inverted voltage of the first voltage;

a third signal processor for receiving and inverting the second voltage to output a third voltage that is an inverted voltage of the second voltage, and generating a shift signal that is transmitted to a subsequent stage of the plurality of stages;

a fourth signal processor for receiving and inverting the third voltage to output a fourth voltage that is an inverted voltage of the third voltage; and

a switch for performing switching between the first power source and an output end of the stage in response to the first control signal.