ORGANIC LIGHT-EMITTING DISPLAY AND METHOD OF DRIVING THE SAME

• US 20160163255A1
• Filed: 04/07/2015
• Published: 06/09/2016
• Est. Priority Date: 12/03/2014
• Status: Abandoned Application

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Bo Yeon, Kwon, Oh Jo
• Application Number:
  US14/681,030
• Publication Number:
  US 20160163255A1
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2350/00 Solving problems of bandwidth in display systems
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: 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

Abstract

An organic light-emitting display devices includes a display panel having first and second pixel groups, each group including first, second, and third pixels which emit light of different colors and a current measurement unit having a plurality of current measurement channels connected to the first and second pixel groups by data lines, wherein each of the current measurement channels includes a first measurement circuit connected to one of the first, second, and third pixels in the first pixel group and measures current characteristics of the connected one of the pixels and a second measurement circuit which measures current characteristics of one of the first, second, and third pixels, in the second pixel group, which emits light of the same color as that of light emitted from the one of the pixels connected to the first measurement circuit.

Claims

1. An organic light-emitting display comprising:

a display panel comprising;

first and second pixel groups, each group comprising;

first, second, and third pixels configured to emit light of different colors; and

a current measurement unit comprising;

a plurality of current measurement channels connected to the first and second pixel groups by data lines,

wherein each of the current measurement channels comprises;

a first measurement circuit connected to one of the first, second, and third pixels in the first pixel group and configured to measure current characteristics of the connected one of the pixels; and

a second measurement circuit configured to measure current characteristics of one of the first, second, and third pixels, in the second pixel group, which is configured to emit light of the same color as that of light emitted from the one of the pixels connected to the first measurement circuit.

2. The organic light-emitting display of claim 1,

wherein the first measurement circuit comprises:

a first integrator circuit,

wherein the second measurement circuit comprises;

a second integrator circuit,

wherein the first integrator circuit comprises;

a first operation amplifier comprising;

a non-inverting input terminal configured to receive a reference voltage; and

an inverting input terminal connected to one of the first, second, and third pixels in the first pixel group;

a first feedback capacitor connected between the inverting input terminal of the first operation amplifier and an output terminal of the first operation amplifier; and

a first feedback switch connected in parallel to the first feedback capacitor, and

wherein the second integrator circuit comprises;

a second operation amplifier comprising;

a non-inverting input terminal configured to receive the reference voltage; and

an inverting input terminal connected to one of the first, second, and third pixels in the second pixel group;

a second feedback capacitor connected between the inverting input terminal of the second operation amplifier and an output terminal of the second operation amplifier; and

a second feedback switch connected in parallel to the second feedback capacitor.

3. The organic light-emitting display of claim 2,

wherein a level of the reference voltage is equal to or higher than a level of a threshold voltage of an organic light-emitting diode in each of the first, second, and third pixels.

4. The organic light-emitting display of claim 2, wherein each of the current measurement channels further comprises:

a first correlated double sampler (CDS) connected to the output terminal of the first operation amplifier;

a first amplifier connected to the first CDS;

a second CDS connected to the output terminal of the second operation amplifier; and

a second amplifier connected to the second CDS.

5. The organic light-emitting display of claim 1, wherein each of the current measurement channels further comprises:

a comparator configured to compare output signals of the first and second measurement circuits; and

an analog-to-digital converter (ADC) configured to convert an output signal of the comparator into a digital value.

6. The organic light-emitting display of claim 1, further comprising:

a multiplexer connected between the display panel and the current measurement unit.

7. The organic light-emitting display of claim 1, further comprising:

a timing controller comprising;

a latch circuit unit connected to the current measurement channels,

a memory unit connected to the latch circuit unit, and

an operation unit configured to receive an output signal of the latch circuit unit and to generate a compensation value.

8. The organic light-emitting display of claim 1, further comprising:

a data driver comprising;

a plurality of digital-to-analog converters (DACs) connected to the data lines; and

a plurality of first switches connected between the display panel and the DACs.

9. The organic light-emitting display of claim 1,

wherein the first pixel comprises:

a first organic light-emitting diode configured to emit light of a first color,

wherein the second pixel comprises;

a second organic light-emitting diode configured to emit light of a second color,

wherein the third pixel comprises;

a third organic light-emitting diode configured to emit light of a third color, and

wherein the first, second, and third colors are different from one another.

10. An organic light-emitting display comprising:

a display panel comprising;

first and second pixel groups, each group comprising;

first, second, and third pixels configured to emit light of different colors; and

a current measurement channel comprising;

a first measurement circuit configured to apply a reference voltage to one of the first, second, and third pixels in the first pixel group during a reference voltage applying period; and

a second measurement circuit configured to apply the reference voltage to a pixel, among the first, second, and third pixels in the second pixel group, which is configured to emit light of a same color as that of light emitted from the pixel receiving the reference voltage from the first measurement circuit, during the reference voltage applying period,

wherein the current measurement channel is configured to measure current characteristics of an organic light-emitting diode in a pixel connected to the first measurement circuit and to measure current characteristics of an organic light-emitting diode in a pixel connected to the second measurement circuit during a measurement period following the reference voltage applying period.

11. The organic light-emitting display of claim 10,

wherein a level of the reference voltage is equal to or higher than that of a threshold voltage of an organic light-emitting diode in a pixel receiving the reference voltage among the first, second, and third pixels.

12. The organic light-emitting display of claim 10,

wherein the first measurement circuit comprises:

a first integrator circuit configured to measure current characteristics of an organic light-emitting diode in a pixel receiving the reference voltage from the first measurement circuit, during the measurement period;

a first amplifier configured to amplify an output signal of the first integrator circuit; and

a first CDS configured to remove noise from an output signal of the first amplifier, and

wherein the second measurement circuit comprises;

a second integrator circuit configured to measure current characteristics of an organic light-emitting diode in a pixel receiving the reference voltage from the second measurement circuit, during the measurement period;

a second amplifier configured to amplify an output signal of the second integrator circuit; and

a second CDS configured to remove noise from an output signal of the second amplifier.

13. The organic light-emitting display of claim 10, wherein the current measurement channel further comprises:

a comparator configured to compare output signals of the first and second measurement circuits; and

an ADC configured to convert an output signal of the comparator into a digital value.

14. The organic light-emitting display of claim 10, further comprising:

a current measurement unit comprising;

a plurality of current measurement channels comprising the current measurement channel; and

a multiplexer configured to provide signal paths between the current measurement channels and the display panel through a switching operation.

15. The organic light-emitting display of claim 14, further comprising:

a timing controller comprising;

a memory unit configured to store output signals of the current measurement channels and

an operation unit configured to generate a compensation value using the output signals of the current measurement channels.

16. The organic light-emitting display of claim 10, further comprising:

a data driver comprising;

a plurality of DACs which are configured to provide data signals to the display panel through data lines; and

a plurality of first switches which are configured to selectively connect and disconnect signal paths between the display panel and the DACs through switching operations.

17. A method of driving an organic light-emitting display comprising:

first and second pixel groups, each comprising;

first, second, and third pixels which emit light of different colors, the method comprising;

applying a reference voltage to one of the first, second, and third pixels in the first pixel group and to one of the first, second, and third pixels in the second pixel group in a reference voltage applying period; and

measuring current characteristics of an organic light-emitting diode in each pixel receiving the reference voltage among the pixels in the first and second pixel groups in a measurement period following the reference voltage applying period,

wherein the pixel receiving the reference voltage among the first, second, and third pixels in the first pixel group and the pixel receiving the reference voltage among the first, second, and third pixels in the second pixel group have a same color.

18. The method of claim 17,

wherein a level of the reference voltage is equal to or higher than that of a threshold voltage of the organic light-emitting diode in each pixel receiving the reference voltage.

19. The method of claim 17, wherein the organic light-emitting display further comprises:

a current measurement channel comprising;

a first measurement circuit which;

applies the reference voltage to one of the first, second, and third pixels in the first pixel group in the reference voltage applying period, and

measures current characteristics of an organic light-emitting diode in the pixel receiving the reference voltage in the measurement period, and

a second measurement circuit which;

applies the reference voltage to a pixel, which emits light of the same color as that of light emitted from the pixel receiving the reference voltage from the first measurement circuit, among the first, second, and third pixels in the second pixel group in the reference voltage applying period, and

measures current characteristics of an organic light-emitting diode in the pixel receiving the reference voltage from the second measurement circuit in the measurement period.

20. The method of claim 19, further comprising:

performing correlated double sampling on output signals of the first and second measurement circuits;

amplifying the two output signals, which underwent the correlated double sampling;

calculating a difference voltage by comparing the two amplified signals; and

converting the difference voltage into a digital signal.