Display device and driving method thereof

• US 9,406,260 B2
• Filed: 09/27/2013
• Issued: 08/02/2016
• Est. Priority Date: 04/22/2013
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Noh, Jae-Du, Jeong, Jin-Tae, Jang, Hwan-Soo
• Primary Examiner(s): Boyd, Jonathan
• Assistant Examiner(s): Azongha, Sardis
• Application Number:
  US14/039,261
• Publication Number:
  US 20140313138A1
• Time in Patent Office: 1,040 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: 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
• CPC Class Codes: G09G 3/3241 the current through the light-emitting element being set using a data current provided by the data driver, e.g. by using a two-transistor current mirror
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

A display device including: a plurality of first electrodes each corresponding to a plurality of light emitting groups on a plurality of pixels including organic light emitting diodes (OLEDs) and a plurality of second electrodes formed on the plurality of first electrodes, having an insulating layer therebetween, wherein a plurality of touch sensing signals are applied to each of the plurality of first electrodes during a non-light emitting period of each of the plurality of light emitting groups and a touched position is determined in response to a magnitude in voltage between the first and second electrodes by a touch from the outside.

Claims

1. A display device, comprising:

a display unit which includes a plurality of pixels including organic light emitting diodes (OLEDs), the plurality of pixels being divided into a plurality of light emitting groups;

a light emitting driving unit which generates a plurality of light emitting signals controlling a light emitting period and a non-light emitting period of each of the plurality of light emitting groups;

a touch sensing unit which includes a plurality of first electrodes formed on the plurality of pixels in a first direction and corresponding to each of the plurality of light emitting groups, and a plurality of second electrodes formed on the plurality of first electrodes in a second direction, having an insulating layer therebetween, and outputs a magnitude of voltage between the first electrode and the second electrode by a touch from the outside as a sensing signal; and

a touch determination unit which applies a plurality of touch scan signals to each of the plurality of first electrodes during the non-light emitting period of each of the plurality of light emitting groups and determines a touched position in response to the sensing signal of the touch sensing unit, wherein the touch determination unit includes a plurality of signal controllers which generate the plurality of touch scan signals, and each of the plurality of signal controllers includes;

a plurality of first transistors which are turned on in response to each of the plurality of scan signals applied to the plurality of scan lines to output a voltage level higher than a first power supply voltage; and

a plurality of second transistors which output the first power supply voltage in response to a light emitting signal applied to the corresponding light emitting group.

2. The display device of claim 1, wherein each of the first electrodes is a cathode electrode.

3. The display device of claim 2, wherein the touch scan signal has the voltage level higher than the first power supply voltage during the non-light emitting period.

4. The display device of claim 2, wherein the touch scan signal alternately has the voltage level higher than the first power supply voltage and the first power supply voltage during the non-light emitting period.

5. The display device of claim 4, further comprising:

a scan driving unit which selectively applies a plurality of scan signals to a plurality of scan lines formed in a region corresponding to the corresponding light emitting group during the non-light emitting period of each of the plurality of light emitting groups.

6. The display device of claim 5, wherein:

the touch determination unit outputs the touch scan signal having the voltage level higher than a first power supply voltage to the corresponding first electrode using the plurality of scan signals during the non-light emitting period of each of the plurality of light emitting groups.

7. The display device of claim 6, wherein:

the touch determination unit outputs the first power supply voltage in response to the light emitting signal of the corresponding light emitting group during the light emitting period of each of the plurality of light emitting groups.

8. The display device of claim 2, further comprising:

a scan driving unit which selectively applies a plurality of first and second scan signals to a plurality of first and second scan lines formed in the corresponding region during the non-light emitting period of each of the plurality of light emitting groups.

9. The display device of claim 8, wherein each pixel of the region corresponding to each light emitting group includes:

a first transistor having a control electrode, a first electrode is electrically connected to a first power supply, and a second electrode in which current corresponding to voltage between the control electrode and the first electrode flows;

a second transistor which is turned on in response to the corresponding first scan signal to apply initialization voltage to the control electrode of the first transistor;

a third transistor which is turned on in response to the corresponding second scan signal to diode-connect the first transistor;

a fourth transistor which is turned on in response to the corresponding second scan signal to apply corresponding data voltage to the first electrode of the first transistor; and

a fifth transistor which is turned on in response to the corresponding light emitting signal to transfer current to the OLED, and

the second transistor is turned on by the corresponding first scan signal and then the third and fourth transistors are turned on by the corresponding second scan signal.

10. The display device of claim 9, wherein:

the touch determination unit outputs a touch scan signal alternately having the first power supply voltage and the voltage level higher than the first power supply voltage using the plurality of first and second scan signals during the non-light emitting period of each of the plurality of light emitting groups.

11. The display device of claim 9, wherein the touch determination unit includes a plurality of signal controllers which generate the plurality of touch scan signals, and each of the plurality of signal controllers includes:

a plurality of sixth transistors which are turned on in response to each of the plurality of first scan signals applied to the plurality of first scan lines corresponding to the corresponding light emitting groups to output a first voltage level higher than the power supply voltage;

a plurality of seventh transistors which are turned on in response to each of the plurality of second scan signals applied to the plurality of second scan lines corresponding to the corresponding light emitting groups to output the power supply voltage; and

a plurality of eighth transistors which output the power supply voltage in response to a light emitting signal applied to the corresponding light emitting group.

12. The display device of claim 9, wherein each pixel corresponding to each light emitting group further includes a capacitor which is connected between the first power supply and the control electrode of the first transistor.

13. A driving method of a display device displaying an image through a plurality of pixels each of which is connected to a plurality of data lines, a plurality of scan lines, and a plurality of light emitting control lines and includes a plurality of organic light emitting diodes (OLEDs), the driving method comprising:

applying first voltage level of light emitting signals to light emitting control lines of a first light emitting group among a plurality of light emitting groups during a first period to block a supply of current to the OLED of the first pixel group corresponding to the first light emitting group;

applying a plurality of scan signals applied to a plurality of scan lines of the first pixel group among the plurality of scan lines during the first period;

applying second voltage level of light emitting signals to light emitting control lines of the first light emitting group during a second period to transfer current corresponding to a plurality of first data voltages to the OLED of the first pixel group; and

generating a touch scan signal having a voltage level higher than a first power supply voltage by a plurality of first transistors which are turned on in response to each of the plurality of scan signals during the first period;

generating the touch scan signal having the first power supply voltage by a plurality of second transistors in response to the second voltage level of light emitting signals during the second period;

applying the touch scan signal to a first touch sensing unit formed on the first pixel group during the first period; and

determining a touch from the outside based on a sensing signal of the first touch sensing unit.

14. The driving method of a display device of claim 13, further comprising:

applying the first voltage level of light emitting signals to light emitting control lines of a second light emitting group among the plurality of light emitting groups during a third period to block a supply of current to the OLED of a second pixel group corresponding to the second light emitting group;

applying the second voltage level of light emitting signals to light emitting control lines of the second light emitting group during a fourth period to transfer current corresponding to a plurality of second data voltages to the OLED of the second pixel group; and

determining a touch from the outside, based on a sensing signal of a second touch sensing unit formed on the second pixel group during the third period.

15. The driving method of a display device of claim 14, wherein:

the first touch sensing unit includes a first electrode corresponding to the first light emitting group and formed on the first pixel group in a first direction and a plurality of second electrodes formed in a second direction, and

the second touch sensing unit includes a third electrode corresponding to the second light emitting group and formed on the second pixel group in the first direction and the plurality of second electrodes.

16. The driving method of a display device of claim 15, wherein:

the first electrode is cathode electrodes of the plurality of OLEDs of the first pixel group and the second electrode is cathode electrodes of the plurality of OLEDs of the second pixel group.

17. The driving method of a display device of claim 16, wherein:

the cathode electrodes of the plurality of OLEDs of the first and second pixel groups each are formed of a single electrode.

18. The driving method of a display device of claim 14, wherein:

the applying during the first period includes selectively applying a plurality of first scan signals through a plurality of first scan lines each connected to the first pixel groups, and

the applying during the third period includes selectively applying a plurality of second scan signals through a plurality of second scan lines each connected to the second pixel groups.

19. The driving method of a display device of claim 18, wherein the determining of the touch during the first period includes:

using the plurality of first scan signals to generate a first touch scan signal; and

applying the first touch scan signal to the first electrode, and

the determining of the touch during the third period includes;

using the plurality of second scan signals to generate a second touch scan signal; and

applying the second touch scan signal to the third electrode.