Touch detection function-attached display apparatus, driving method and driving circuit therefor with switchable AC and DC driving, and electronic apparatus

• US 8,952,923 B2
• Filed: 08/08/2011
• Issued: 02/10/2015
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Inventors: Mizuhashi, Hiroshi, Kida, Yoshitoshi
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): SCHNIREL, ANDREW B
• Application Number:
  US13/137,344
• Publication Number:
  US 20120068961A1
• Time in Patent Office: 1,282 Days
• Field of Search: 345/174
• US Class Current: 345/174
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

Provided is a touch-detection-function-attached display apparatus including: common-driving electrodes disposed in parallel to extend in one direction; a display device performing display based on pixel and display-driving signals; a touch-detection device detecting an externally-approaching object based on a touch-detection-driving signal; and a scan-driving unit performing a first-scan driving for sequentially-applying the display-driving signal to the common-driving electrodes in a time-division manner and a second-scan driving for sequentially-applying the touch-detection-driving signal to the common-driving electrodes in a time-division manner at a scan speed different from the first-scan-driving and applying a DC potential to the common-driving electrode which is not selected as an object of the first and second scan driving, wherein the touch-detection-driving signal includes a DC portion sustained at the DC potential in a time interval where the pixel signal is applied to the display device and a pulse portion in a time interval other than the pixel-signal-application time interval.

Claims

1. A touch detection function-attached display apparatus comprising:

a plurality of common driving electrodes which are disposed in parallel so as to extend in one direction and are applied with an AC signal and a DC potential;

a display device which has a plurality of pixel electrodes and performs display based on a pixel signal applied to the plurality of pixel electrodes and a display driving signal applied to the plurality of common driving electrodes;

a touch detection device which has a touch detection electrode and detects an externally approaching object based on a touch detection signal outputted from the touch detection electrode with a touch detection driving signal applied to the plurality of common driving electrodes; and

a scan driving unit which

performs a first scan driving in which the display driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner and the pixel signal is applied to a pixel electrode corresponding to a common driving electrode which is applied with the display driving signal, in synchronization with the application of the display driving signal,

performs a second scan driving in which the touch detection driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner at a scan speed different from that of the first scan driving, and

applies the DC potential to the common driving electrodes which are not selected as an object of the first scan driving and the second scan driving,

wherein, in the first scan driving, the scan driving unit applies the AC signal as the display driving signal to the plurality of common driving electrodes,

the touch detection driving signal includes a DC portion and a pulse portion,

a horizontal time interval includes a pixel signal application time interval where the pixel signal is applied to the display device, and a time interval other than the pixel signal application time interval,

in the second scan driving, the scan driving unit applies the DC potential as the DC portion to the plurality of common driving electrodes in the pixel signal application time interval and applies the AC signal as the pulse portion to the plurality of common driving electrodes in the time interval other than the pixel signal application time interval,

in the first scan driving, the scan driving unit applies the display driving signal to one of the plurality of common driving electrodes for each horizontal time,

in the second scan driving, the scan driving unit applies the touch detection driving signal to two or more common driving electrodes, which are adjacent to each other, for each horizontal time,

a speed of the second scan driving is higher than that of the first scan driving, and

when a common driving electrode which is an object of the first scan driving and one of two or more common driving electrodes which are objects of the second scan driving are overlapped,

the scan driving unit applies the display driving signal to the overlapped common driving electrode without applying the touch detection driving signal, and

the scan driving unit performs the second scan driving to common driving electrodes other than the overlapped common driving electrode among the two or more common driving electrodes which are objects of the second scan driving by applying the DC potential in the pixel signal application time interval and applying the AC signal in the time interval other than the pixel signal application time interval.

2. The touch detection function-attached display apparatus according to claim 1,

wherein the scan driving unit includes a first switch which transfers the AC signal,

wherein in the first scan driving, by turning on the first switch, the AC signal is applied as the display driving signal to the common driving electrode, and

wherein in the second scan driving, by turning on the first switch in the time interval other than the pixel signal application time interval, the pulse portion of the touch detection driving signal is generated by using the AC signal applied via the first switch, and applied to the common driving electrode.

3. The touch detection function-attached display apparatus according to claim 2,

wherein the scan driving unit further includes a second switch which transfers the DC potential, and

wherein, by turning on the second switch in the pixel signal application time interval, the DC portion of the touch detection driving signal is generated and applied to the common driving electrode.

4. The touch detection function-attached display apparatus according to claim 3, wherein the scan driving unit applies the DC potential to the common driving electrode by turning on the second switch.

5. The touch detection function-attached display apparatus according to claim 1, wherein the touch detection device detects an externally approaching object by using a change in electrostatic capacitance based on approach or contact of the externally approaching object.

6. The touch detection function-attached display apparatus according to claim 3, wherein the AC signal is a rectangular wave signal.

7. The touch detection function-attached display apparatus according to claim 6, wherein the DC potential is equal to a time average of voltage of the display driving signal.

8. The touch detection function-attached display apparatus according to claim 6, wherein the scan driving unit generates the touch detection driving signal based on a mask signal including pulses spanning before and after the transition of the AC signal,

when the pulse of the mask signal is supplied to the scan driving unit, the scan driving unit generates the pulse portion of the touch detection driving signal by turning on the first switch and turning off the second switch, and

when the pulse of the mask signal is not supplied to the scan driving unit, the scan driving unit generates the DC portion of the touch detection driving signal by turning off the first switch and turning on the second switch.

9. A driving circuit comprising

a scan driving unit configured so that, with respect to a touch detection function-attached display unit having a plurality of common driving electrodes which are disposed in parallel so as to extend in one direction and are applied with an AC signal and a DC potential, a display device which has a plurality of pixel electrodes and performs display based on a pixel signal applied to the plurality of pixel electrodes and a display driving signal applied to the plurality of common driving electrodes, and a touch detection device which has a touch detection electrode and detects an externally approaching object based on a touch detection signal outputted from the touch detection electrode with a touch detection driving signal applied to the plurality of common driving electrodes, the scan driving unit performs a first scan driving in which the display driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner and the pixel signal is applied to a pixel electrode corresponding to a common driving electrode which is applied with the display driving signal, in synchronization with the application of the display driving signal, performs a second scan driving in which the touch detection driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner at a scan speed different from that of the first scan driving and applies the DC potential to common driving electrodes which are not selected as an object of the first scan driving and the second scan driving,

wherein, in the first scan driving, the scan driving unit applies the AC signal as the display driving signal to the plurality of common driving electrodes,

the touch detection driving signal includes a DC portion and a pulse portion,

a horizontal time interval includes a pixel signal application time interval where the pixel signal is applied to the display device, and a time interval other than the pixel signal application time interval,

in the second scan driving, the scan driving unit applies the DC potential as the DC portion to the plurality of common electrodes in the pixel signal application time interval and applies the AC signal as the pulse portion to the plurality of common driving electrodes in the time interval other than the pixel signal application time interval,

in the first scan driving, the scan driving unit applies the display driving signal to one of the plurality of common driving electrodes for each horizontal time,

in the second scan driving, the scan driving unit applies the touch detection driving signal to two or more common driving electrodes, which are adjacent to each other, for each horizontal time,

a speed of the second scan driving is higher than that of the first scan driving, and

when a common driving electrode which is an object of the first scan driving and one of two or more common driving electrodes which are objects of the second scan driving are overlapped,

the scan driving unit applies the display driving signal to the overlapped common driving electrode without applying the touch detection driving signal, and

the scan driving unit performs the second scan driving to common driving electrodes other than the overlapped common driving electrode among the two or more common driving electrodes which are objects of the second scan driving by applying the DC potential in the pixel signal application time interval and applying the AC signal in the time interval other than the pixel signal application time interval.

10. A driving method for a touch detection function-attached display apparatus including a plurality of common driving electrodes which are disposed in parallel so as to extend in one direction and are applied with an AC signal and a DC potential, a display device which has a plurality of pixel electrodes and performs display based on a pixel signal applied to the plurality of pixel electrodes and a display driving signal applied to the plurality of common driving electrodes, and a touch detection device which has a touch detection electrode and detects an externally approaching object based on a touch detection signal outputted from the touch detection electrode with a touch detection driving signal applied to the plurality of common driving electrodes, the driving method comprising:

performing a first scan driving operation in which display based on a pixel signal and a display driving signal is performed by sequentially applying the display driving signal to the plurality of common driving electrodes in a time division manner and by sequentially performing an operation for applying the pixel signal to a pixel electrode corresponding to a common driving electrode, which is applied with the display driving signal, in synchronization with the application of the display driving signal, in a time division manner;

performing a second scan driving operation in which the touch detection driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner at a scan speed different from that of the first scan driving operation; and

applying the DC potential to common driving electrodes which are not selected as an object of the first and the second scan driving operations,

wherein, in the first scan driving, the AC signal is applied as the display driving signal to the plurality of common driving electrodes,

the touch detection driving signal includes a DC portion and a pulse portion,

a horizontal time interval includes a pixel signal application time interval where the pixel signal is applied to the display device, and a time interval other than the pixel signal application time interval,

in the second scan driving, the DC potential is applied as the DC portion to the plurality of common driving electrodes in the pixel signal application time interval and the AC signal is applied as the pulse portion to the plurality of common driving electrodes in the time interval other than the pixel signal application time interval,

in the first scan driving, the display driving signal is applied to one of the plurality of common driving electrodes for each horizontal time,

in the second scan driving, the touch detection driving signal is applied to two or more common driving electrodes, which are adjacent each other, for each horizontal time,

a speed of the second scan driving is higher than that of the first scan driving, and

when a common driving electrode which is an object of the first scan driving and one of two or more common driving electrodes which are objects of the second scan driving are overlapped,

the display driving signal is applied to the overlapped common driving electrode without the touch detection driving signal being applied, and

the second scan driving is performed to common driving electrodes other than the overlapped common driving electrode among the two or more common driving electrodes which are objects of the second scan driving by applying the DC potential in the pixel signal application time interval and applying the AC signal in the time interval other than the pixel signal application time interval.

11. An electronic apparatus comprising:

a touch detection function-attached display apparatus; and

a controller which performs operation control using the touch detection function-attached display apparatus;

wherein the touch detection function-attached display apparatus includes;

a plurality of common driving electrodes which are disposed in parallel so as to extend in one direction and are applied with an AC signal and a DC potential;

a display device which has a plurality of pixel electrodes and performs display based on a pixel signal applied to the plurality of pixel electrodes and a display driving signal applied to the plurality of common driving electrodes;

a touch detection device which has a touch detection electrode and detects an externally approaching object based on a touch detection signal outputted from the touch detection electrode with a touch detection driving signal applied to the plurality of common driving electrodes; and

a scan driving unit which

performs a first scan driving in which the display driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner and the pixel signal is applied to a pixel electrode corresponding to a common driving electrode which is applied with the display driving signal, in synchronization with the application of the display driving signal,

performs a second scan driving in which the touch detection driving signal is sequentially applied to the plurality of the common driving electrodes in a time division manner at a scan speed different from that of the first scan driving, and

applies the DC potential to common driving electrodes on which the first scan driving and the second scan driving are not performed, and

wherein, in the first scan driving, the scan driving unit applies the AC signal as the display driving signal to the plurality of common driving electrodes,

the touch detection driving signal includes a DC portion and a pulse portion,

a horizontal time interval includes a pixel signal application time interval where the pixel signal is applied to the display device, and a time interval other than the pixel signal application time interval,

in the second scan driving, the scan driving unit applies the DC potential as the DC portion to the plurality of common driving electrodes in the pixel signal application time interval and applies the AC signal as the pulse portion to the plurality of common driving electrodes in the time interval other than the pixel signal application time interval,

in the first scan driving, the scan driving unit applies the display driving signal to one of the plurality of common driving electrodes for each horizontal time,

in the second scan driving, the scan driving unit applies the touch detection driving signal to two or more common driving electrodes, which are adjacent to each other, for each horizontal time,

a speed of the second scan driving is higher than that of the first scan driving, and

when a common driving electrode which is an object of the first scan driving and one of two or more common driving electrodes which are objects of the second scan driving are overlapped,

the scan driving unit applies the display driving signal to the overlapped common driving electrode without applying the touch detection driving signal, and

the scan driving unit performs the second scan driving to common driving electrodes other than the overlapped common driving electrode among the two or more common driving electrodes which are objects of the second scan driving by applying the DC potential in the pixel signal application time interval and applying the AC signal in the time interval other than the pixel signal application time interval.