Liquid crystal display integrated with touch sensor

• US 9,390,675 B2
• Filed: 08/28/2014
• Issued: 07/12/2016
• Est. Priority Date: 10/04/2013
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Chung, Jae-Mo
• Primary Examiner(s): Tzeng, Fred
• Application Number:
  US14/471,548
• Publication Number:
  US 20150097817A1
• Time in Patent Office: 684 Days
• Field of Search: 345/206
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• 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 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence

Abstract

A liquid crystal display with a touch sensor includes a first substrate having a plurality of pixels coupled to gate lines and data lines and a second substrate opposing the first substrate. The display also includes a plurality of common electrodes corresponding to respective pixels, a plurality of sensing electrodes on the second substrate, a touch controller to supply a channel selection signal and a touch control signal to a common electrode driver during a touch driving period, and a common electrode driver to progressively supply a touch driving signal to the common electrodes based on the channel selection signal. The touch driving signal may have the same frequency as the touch control signal.

Claims

1. A liquid crystal display with a touch sensor, the display comprising:

a first substrate including a plurality of pixels coupled to gate lines and data lines;

a second substrate opposing the first substrate;

a plurality of common electrodes corresponding to respective pixels;

a plurality of sensing electrodes on the second substrate;

a touch controller to supply a channel selection signal and a touch control signal to a common electrode driver during a touch driving period; and

a common electrode driver to progressively supply a touch driving signal to the common electrodes based on the channel selection signal, the touch driving signal having a same frequency as the touch control signal.

2. The display as claimed in claim 1, wherein the touch controller is to change the frequency of the touch control signal.

3. The display as claimed in claim 2, wherein the touch controller is to maintain the frequency of the channel selection signal when the frequency of the touch control signal is changed.

4. The display as claimed in claim 1, further comprising:

a data driver to output a data signal to the data lines during a display period; and

a gate driver to output a gate-on signal to the gate lines during the display period.

5. The display as claimed in claim 4, wherein the gate driver is to output a gate-off signal to the gate lines during the touch driving period.

6. The display as claimed in claim 4, wherein the display period and touch driving period are alternately repeated.

7. The display as claimed in claim 4, wherein the common electrode driver is to supply a same common voltage to the common electrodes during the display period.

8. The display as claimed in claim 4, wherein the gate driver includes a plurality of stages to receive first and second clock signals.

9. The display as claimed in claim 8, wherein each stage of the gate driver includes:

a first transistor coupled between a first clock terminal and an output terminal, the first transistor having a gate electrode coupled to a first node;

a second transistor coupled between a first input terminal and the first node, the second transistor having a gate electrode coupled to the first input terminal;

a third transistor coupled between the first node and a voltage terminal, the third transistor having a gate electrode coupled to a second input terminal;

a fourth transistor coupled between the output terminal and the voltage terminal, the fourth transistor having a gate electrode coupled to a second clock terminal;

a fifth transistor coupled between the output terminal and the voltage terminal, the fifth transistor having a gate electrode coupled to a second node;

a sixth transistor coupled between the second node and the voltage terminal, the sixth transistor having a gate electrode coupled to the first node; and

a seventh transistor coupled between the first node and the voltage terminal, the seventh transistor having a gate electrode coupled to the second node.

10. The display as claimed in claim 9, wherein each stage of the gate driver further includes:

a first capacitor coupled between the first node and output terminal; and

a second capacitor coupled between the first clock terminal and second node.

11. The display as claimed in claim 10, wherein:

the first and second clock signals are respectively input to the first and second clock terminals of an odd-numbered stage, and

the second and first clock signals are respectively input to the first and second clock terminals of an even-numbered stage.

12. The display as claimed in claim 11, wherein:

a scan start signal or the gate-on signal of a previous stage is input to the first input terminal, and

the gate-on signal of a next stage is input to the second input terminal.

13. The display as claimed in claim 12, wherein a gate-off voltage is applied to the voltage terminal.

14. The display as claimed in claim 8, wherein the first and second clock signals have opposite phases.

15. The display as claimed in claim 1, further comprising:

a display controller to supply the first and second clock signals to the gate driver, in synchronization with the channel selection signal, during the touch driving period.

16. The display as claimed in claim 1, wherein the common electrodes are positioned on the first or second substrate.

17. The display as claimed in claim 1, wherein the common electrodes and the sensing electrodes are positioned in directions intersecting each other.

18. The display as claimed in claim 1, further comprising:

a back light below the first substrate.

19. The display as claimed in claim 1, further comprising:

a liquid crystal layer positioned between the first and second substrates, alignment of the liquid crystal layer being controlled by an electric field between pixel electrodes and the common electrodes.

20. A controller, comprising:

a touch controller to generate a channel selection signal during a display period and a touch control signal during a touch driving period; and

a common electrode driver to progressively supply the touch driving signal to a plurality of common electrodes based on the channel selection signal, the touch driving signal having a same frequency as the touch control signal.