DISPLAY DEVICE

• US 20180181242A1
• Filed: 12/20/2017
• Published: 06/28/2018
• Est. Priority Date: 12/28/2016
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: MIZUHASHI, Hiroshi, KURASAWA, Hayato, KIDA, Yoshitoshi, UEHARA, Toshinori, NAKANISHI, Takayuki
• Granted Patent: US 10,572,047 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 2310/0264 Details of driving circuits

Abstract

A display device comprises a first power supply line supplying a first potential, a second power supply line supplying a second potential, a third power supply line supplying a touch driving signal, and a display unit including a plurality of sub-pixels. The display unit comprises a plurality of first electrodes respectively provided in the plurality of sub-pixels and electrically connected to the first power supply line, a second electrode provided to be common among the plurality of sub-pixels and electrically connected to the second power supply line, a light emitting layer provided between the first electrode and the second electrode, a plurality of third electrodes electrically connected to the third power supply line, and a signal control circuit supplying a signal synchronized with a touch driving signal to the second electrode in a period in which a touch driving signal is supplied to the plurality of third electrodes.

Claims

1. A display device comprising:

a first power supply line supplying a first potential;

a second power supply line supplying a second potential different from the first potential;

a third power supply line supplying a touch driving signal; and

a display unit including a plurality of sub-pixels;

wherein the display unit comprising;

a plurality of first electrodes respectively provided in the plurality of sub-pixels and electrically connected to the first power supply line;

a second electrode provided to be common among the plurality of sub-pixels and electrically connected to the second power supply line;

a light emitting layer provided between the first electrode in each of the plurality of sub-pixels and the second electrode;

an insulating layer provided on the second electrode;

a plurality of third electrodes provided on the insulating layer and electrically connected to the third power supply line; and

a signal control circuit supplying a signal synchronized with a touch driving signal to the second electrode in a period in which the touch driving signal is supplied to the plurality of third electrodes from the third power supply line.

2. The display device according to claim 1, wherein:

the touch driving signal is a pulse signal; and

at least one of a high-level potential and a low-level potential of the pulse signal differs from the second potential in a period in which the touch driving signal is not supplied to the plurality of third electrodes.

3. The display device according to claim 2, wherein the low-level potential of the pulse signal is equal to the second potential, and the high-level potential of the pulse signal is higher than the second potential.

4. The display device according to claim 1, wherein the signal control circuit synchronizes the second potential with a potential of a touch driving signal in a period in which the touch driving signal is supplied to the third electrodes.

5. The display device according to claim 1, further comprising a switch switching a state where the second electrode is connected to the second power supply line and a state where the second electrode is connected to the third power supply line.

6. The display device according to claim 5, wherein the second electrode is connected to the third power supply line via the switch in a period in which a touch driving signal is supplied to the third electrodes.

7. The display device according to claim 1, further comprising:

a fourth power supply line supplying a signal synchronized with the touch driving signal to the second electrode; and

a switch switching a state where the second electrode is connected to the second power supply line and a state where the second electrode is connected to the fourth power supply line.

8. The display device according to claim 7, wherein the second electrode is connected to the fourth power supply line via the switch in a period in which a touch driving signal is supplied to the third electrodes.

9. The display device according to claim 1, further comprising:

a gate line extending in a first direction; and

a video signal line extending in a second direction intersecting the first direction and the video signal line supplying a video signal,

wherein;

each of the plurality of sub-pixels includes a driving transistor, a pixel selection transistor, and a capacitive element;

the driving transistor has a drain or source electrode electrically connected to the first power supply line and has a source or drain electrode electrically connected to the corresponding first electrode;

the pixel selection transistor has a drain or source electrode connected to a gate electrode of the driving transistor, has a source or drain electrode electrically connected to the video signal line, and has a gate electrode connected to the gate line; and

the capacitive element has one electrode electrically connected to a gate electrode of the driving transistor and has another electrode electrically connected to the first electrode.

10. The display device according to claim 9, further comprising an output transistor provided between the first power supply line and the drain or source electrode of the driving transistor,

wherein the output transistor switches an electrical connection state or disconnection state between the first power supply line and the driving transistor.

11. The display device according to claim 9, wherein:

the signal control circuit sequentially repeats, for a row pixel including sub-pixels arranged side by side in the first direction,

an initialization period in which a potential of at least one of the source electrode, the drain electrode, and the gate electrode of the driving transistor is initialized,

a writing period in which a charge corresponding to the video signal supplied to the gate electrode of the driving transistor via the video signal line is retained in the capacitive element, and

a light emission period in which the light emitting layer emits light at a luminescence intensity corresponding to the video signal;

the touch driving signal is supplied to a third electrode from the third power supply line in a predetermined period in the light emission period; and

a signal synchronized with the touch driving signal is supplied to the second electrode in the predetermined period.

12. The display device according to claim 1, further comprising:

a touch detection circuit electrically connected to each of the plurality of third electrodes and the touch detection circuit detects a change in a capacitance of the third electrode,

wherein the touch detection circuit comprises a detection unit detecting the change in the capacitance of each of the third electrodes based on a signal corresponding to the capacitance of the third electrode.

13. The display device according to claim 12, wherein the touch detection circuit comprises a plurality of detection units.

14. The display device according to claim 12, wherein the detection unit further comprises a multiplexer having two or more input terminals electrically connected to two or more of the plurality of third electrodes and an output terminal outputting signals respectively corresponding to capacitances of the two or more third electrodes connected to the two or more input terminals in a time divisional manner.

15. The display device according to claim 1, further comprising:

a first substrate provided with the plurality of sub-pixels; and

a second substrate facing the first substrate and provided on the insulating layer,

wherein the third electrode is provided on a surface on the opposite side to the surface, facing the first substrate, of the second substrate.

16. The display device according to claim 1, further comprising:

a first substrate provided with the plurality of sub-pixels; and

a second substrate facing the first substrate and provided on the insulating layer;

a plurality of color filters provided between the second substrate and the insulating layer and respectively corresponding to the plurality of sub-pixels; and

a light shielding layer provided between adjacent color filters of the plurality of color filters between the second substrate and the insulating layer,

wherein the third electrode is provided on the light shielding layer.

17. The display device according to claim 9, further comprising:

a touch detection circuit electrically connected to each of the plurality of third electrodes and the touch detection circuit detects a change in a capacitance of the third electrode,

wherein the touch detection circuit comprises a detection unit detecting the change in the capacitance of each of the third electrodes based on a signal corresponding to the capacitance of the third electrode.

18. The display device according to claim 17, wherein the touch detection circuit comprises a plurality of detection units.

19. The display device according to claim 17, wherein the detection unit further comprises a multiplexer having two or more input terminals electrically connected to two or more of the plurality of third electrodes and an output terminal outputting signals respectively corresponding to capacitances of the two or more third electrodes connected to the two or more input terminals in a time divisional manner.