DISPLAY DEVICE

• US 20170003807A1
• Filed: 06/27/2016
• Published: 01/05/2017
• Est. Priority Date: 07/01/2015
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: ABE, Hiroyuki
• Granted Patent: US 10,088,944 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/0445 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 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T

Abstract

According to one embodiment, a display device includes common electrodes, detection electrodes, a common-electrode drive circuit including shift registers and switch circuits electrically connected to the shift registers, and a driver which outputs four-phase clock signals and a touch-drive signal, wherein a reset operation of the each shift register is controlled by predetermined two of the four-phase clock signals, each of the switch circuits connects a signal line from the driver to common electrodes based on a shift signal output from an associated shift register, and the each switch circuit causes the touch-drive signal from the driver to be supplied to the common electrodes of the block during a period from time at which the shift signal is output from the associated shift register to time at which a predetermined one of the four-phase clock signals is input.

Claims

1. A display device comprising:

a plurality of common electrodes extending in a first direction and arranged in parallel with each other;

a plurality of detection electrodes extending in a second direction crossing the first direction and arranged in parallel with each other;

a common-electrode drive circuit including a plurality of shift registers connected in series to each other and a plurality of switch circuits electrically connected to the shift registers, respectively; and

a driver which outputs four-phase clock signals and a touch-drive signal to control the common-electrode drive circuit,

wherein

each of the shift registers is configured to transfer a shift signal, and a reset operation of the each shift register is controlled by predetermined two of the four-phase clock signals,

each of the switch circuits connects a signal line from the driver to a common electrode or electrodes of an associated block based on a shift signal output from an associated shift register, and

the each switch circuit causes the touch-drive signal from the driver to be supplied to the common electrode or electrodes of the block during a period from time at which the shift signal is output from the associated shift register to time at which a predetermined one of the four-phase clock signals is input.

2. The display device according to claim 1, wherein

the each switch circuit connects a signal line for outputting the touch-drive signal to the common electrode or electrodes of the block, when the associated shift register outputs the shift signal,

the each switch circuit supplies the touch-drive signal to the signal line when the touch-drive signal is input from the driver, and

the each switch circuit disconnects the signal line from the common electrode or electrodes of the block, when the predetermined one of the four-phase clock signals is input from the driver.

3. The display device according to claim 2, wherein

the driver successively and repeatedly outputs first to fourth clock signals which are the four-phase clock signals, and

where a clock signal for controlling the transfer operation of a shift register is an N^th clock signal, a clock signal for controlling the reset operation of the shift register is an M^th clock signal, and a clock signal to be input to a switch circuit connected to the shift register is a K^th clock signal, N, M and K are integers of 4 or less, and the following relationships are satisfied:

(N+2)≡

M mod 4

when M≡

1 mod 4 or M≡

2 mod 4, K=4, and

when M≡

3 mod 4 or M≡

0 mod 4, K=2.

4. The display device according to claim 3, wherein the driver repeatedly performs an operation for outputting the touch-drive signal to the common-electrode drive circuit after successively outputting the first to third clock signals to the common-electrode drive circuit, and then outputting the touch-drive signal to the common-electrode drive circuit after successively outputting two clock signals from the fourth clock signal to the common-electrode drive circuit.

5. The display device according to claim 3, wherein the driver repeatedly performs an operation for outputting the touch-drive signal to the common-electrode circuit after successively outputting two clock signals from the first clock signal to the common-electrode circuit.

6. The display device according to claim 3, wherein

the common electrodes are used as electrodes for a touch-drive operation and electrodes for an image display operation, and

the each switch circuit applies a common voltage for the image display operation to the common electrode or electrodes of the block, when the image display operation is performed, and supplies the touch-drive signal to the common electrode or electrodes of the block when a touch detection operation is performed.

7. The display device according to claim 6, wherein the driver further outputs to the common-electrode drive circuit a signal for indicating whether the image display operation is performed or the touch-drive operation is performed and the common voltage.

8. A display device comprising:

common electrodes doubling as electrodes for an image display operation and electrodes for a touch detection operation; and

a drive circuit which drives the common electrodes,

wherein

the common electrodes include an n^th common electrode (n≧

1), an n+1^th common electrode and an n+2^th common electrode,

the drive circuit includes;

switch circuits which output signals for the touch detection signal or signals for the image display operation to the common electrodes in a switchable manner; and

shift register circuits which output control signals to the switch circuits,

the switch circuits include an n^th switch circuit, an n+1^th switch circuit and an n+2^th switch circuit,

the n^th switch circuit, the n+1^th switch circuit and the n+2^th switch circuit hold control signals from the shift register circuits as an n^th switch signal, an n+1^th switch signal and an n+2^th switch signal, respectively,

the n^th switch circuit, the n+1^th switch circuit and the n+2^th switch circuit are electrically connected to the n^th common electrode, the n+1^th common electrode and the n+2^th common electrode, respectively, and

in a period in which the n^th switch circuit and the n+1^th switch circuit simultaneously hold the n^th switch signal and the n+1^th switch signal, respectively, the n+2^th switch circuit starts to hold the n+2^th switch signal.

9. The display device according to claim 8, wherein

clock signals each of which comprises a first voltage and a second voltage are input to the shift register circuits,

the clock signals include a first clock signal, a second clock signal, a third clock signal and a fourth clock signal,

the first clock signal, the second clock signal, the third clock signal and the fourth clock signal are transformed into first voltages in this order,

the n^th switch circuit, to which the first voltage obtained by transforming the first clock signal is input as a control signal, and the n+1^th switch circuit, to which the first voltage obtained by transforming the second clock signal to input as another control signal, stop holding of the n^th switch signal and holding of the n+1^th switch signal, respectively, upon reception of the first voltage from the fourth clock signal.

10. The display device according to claim 8, wherein the switch circuits include:

first output transistors which output signals for the touch detection operation; and

second output transistors which output signals for the image display operation.

11. The display device according to claim 10, wherein

a touch period signal indicating a touch detection period is input to a switch circuit, and

the switch circuit supplies the touch period signal to the first output transistor thereof to turn on the first output transistor, in accordance with the control signal from an associated shift register.

12. The display device according to claim 10, wherein in a period in which the n^th switch circuit and the n+1^th switch circuit simultaneously hold the n^th switch signal and the n+1^th switch signal, respectively, the first output transistors of the n^th switch circuit and the n+1^th switch circuit are turned on.

13. The display device according to claim 10, wherein after the n+2^th switch circuit holds the n+1^th switch signal, the first output transistors of the n+1^th switch circuit and the n+2^th switch circuit are turned on.

14. The display device according to claim 10, wherein

a display period signal indicating a display period is input to a switch circuit, and

the switch circuit supplies the display period signal to the second output transistor thereof to turn on the second output transistor, in accordance with a control signal from an associated shift register.

15. A display device comprising:

a plurality of common electrodes doubling as electrodes for an image display operation and electrodes for a touch detection operation; and

a plurality of drive circuits for driving the common electrodes,

wherein

the drive circuits include;

switch circuits each of which outputs a signal for the touch detection operation or a signal for the image display operation to the common electrodes in a switchable manner; and

shift register circuits each of which outputs a control signal to an associated one of the switch circuits,

the switch circuits include hold circuits each of which holds the control signal from an associated one of the shift register circuits as a switch signal,

clock signals each of which comprises a first voltage and a second voltage are input to the shift register circuits,

the clock signals include a first clock signal, a second clock signal, a third clock signal and a fourth clock signal,

the first clock signal, the second clock signal, the third clock signal and the fourth clock signal are transformed into first voltages in this order,

the common electrodes include a first common electrode and a second common electrode which are arranged adjacent to each other,

the switch circuits include a first switch circuit which outputs a signal for the touch detection operation to the first common electrode, upon reception of the first clock signal, which is input as a control signal,

the switch circuits include a second switch circuit which outputs a signal for the touch detection operation to the second common electrode upon reception of the second clock signal, which is input as another control signal, and

hold circuits of the first switch circuit and the second switch circuit stop holding of respective switch signals with the first voltage of the fourth clock signal.

16. The display device according to claim 15, wherein the switch circuits include:

first output transistors each of which outputs a signal for the touch detection operation; and

second output transistors each of which outputs a signal for the image display operation.

17. The display device according to claim 16, wherein

a touch period signal indicating a touch detection period is input to a switch circuit, and

the switch circuit supplies the touch period signal to the first output transistor thereof to turn on the first output transistor, in accordance with the switch signal.

18. The display device according to claim 17, wherein in a period in which the first switch circuit and the second switch circuit simultaneously hold the switch signals, first output transistors of the first switch circuit and the second switch circuit are turned on by the touch period signal.

19. The display device according to claim 17, wherein

a third common electrode is located adjacent to the second common electrode,

a third switch circuit outputs the signal for the touch detection operation to the third common electrode, and

after the third switch circuit holds a switch signal, first output transistors of the first to third switch circuits are turned on.

20. The display device according to claim 16, wherein

a display period signal indicating a display period is input to a switch circuit, and

the switch circuit supplies the display period signal to the second output transistor thereof to turn on the second output transistor, in accordance with the switch signal.