Systems for displaying images

• US 20100013779A1
• Filed: 07/07/2009
• Published: 01/21/2010
• Est. Priority Date: 07/15/2008
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: TPO Displays Corporation (InnoLux Corporation)
• Inventors: Wu, Tse-Hung
• Granted Patent: US 8,300,024 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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

Abstract

A system for displaying images includes a touch sensing circuit. The touch sensing circuit comprises a voltage storage unit for detecting whether a touch event has occurred and generates a corresponding voltage. The voltage storage unit comprises first to third capacitors. The first capacitor has a first terminal coupled to a ground terminal and a second terminal coupled to a first node. The second capacitor has a first terminal coupled to the ground terminal and a second terminal coupled to a second node. When the voltage storage unit detects that a touch event has occurred, the second node is coupled to an AC voltage. The third capacitor is formed between the first and second nodes. When the touch event has occurred, a value of the third capacitor is changed, so that the corresponding voltage at the first node is changed.

Claims

1. A system for displaying images, comprising:

a touch sensing circuit comprising a voltage storage unit for detecting whether a touch event has occurred and generating a corresponding voltage, wherein the voltage storage unit comprises;

a first capacitor having a first terminal coupled to a ground terminal and a second terminal coupled to a first node;

a second capacitor having a first terminal coupled to the ground terminal and a second terminal coupled to a second node, wherein when the voltage storage unit detects whether a touch event has occurred, and the second node is coupled to an alternating current (AC) voltage;

a third capacitor formed between the first and second nodes, wherein when the touch event has occurred, a value of the third capacitor is changed, so that the corresponding voltage at the first node is changed;

a first switch element having a first terminal coupled to the first node and a second terminal coupled to the second node; and

a second switch element having a first terminal coupled to the first node and a second terminal.

2. The system as claimed in claim 1, wherein the voltage storage unit further comprises a fourth capacitor coupled between the first node and the ground terminal.

3. The system as claimed in claim 1, wherein when the voltage storage unit detects whether a touch event has occurred, in a first period, the first switch element is turned on, and the AC voltage is changed from a relatively high voltage to a relatively low voltage, so that the corresponding voltage is charged to the relatively low voltage.

4. The system as claimed in claim 1,

wherein when the voltage storage unit detects whether a touch event has occurred, in a second period, the first switch element is turned off, and the AC voltage is changed from the relatively low voltage to the relatively high voltage;

wherein when the touch even does not occur, the corresponding voltage is at a first level; and

wherein when the touch event has occurred, the value of the third capacitor is changed, and the corresponding voltage is changed to a second level when the value of the third capacitor is changed.

5. The system as claimed in claim 1, wherein the touch sensing circuit further comprises an integration unit, coupled to the second terminal of the second switch element, for integrating the corresponding voltage and generating an integration signal.

6. The system as claimed in claim 5, wherein the integration unit comprises:

a third switch element having a first terminal coupled to the second terminal of the second switch element and a second terminal;

a fifth capacitor having a first terminal coupled to the second terminal of the third switch element and a second terminal;

a fourth switch element having a first terminal coupled to the second terminal of the third switch element and a second terminal coupled to a relatively low voltage of the AC voltage;

a fifth switch element having a first terminal coupled to the second terminal of the fifth capacitor and a second terminal;

a sixth switch element having a first terminal coupled to the second terminal of the fifth capacitor and a second terminal coupled to the relatively low voltage;

an operational amplifier having an inverting input terminal coupled to the second terminal of the fifth switch element, a non-inverting input terminal coupled to the relatively low voltage, and an output terminal;

a sixth capacitor coupled between the inverting input terminal and the output terminal of the operational amplifier;

a seventh switch element between the inverting input terminal and the output terminal of the operational amplifier; and

an eighth switch element, coupled to the output terminal of the operational amplifier, for providing the integration signal.

7. The system as claimed in claim 6, wherein the touch sensing circuit further comprises a voltage amplifying unit, coupled to the eighth switch element, for receiving and amplifying the integration signal when the eighth switch element is turned on to generate an output signal.

8. The system as claimed in claim 1 further comprising a touch panel, wherein the touch panel comprises the touch sensing circuit.

9. The system as claimed in claim 8 further comprises an electronic device, wherein the electronic device comprises a display panel for displaying images, and the system communicates with a user trough the touch panel.

10. The system as claimed in claim 9, wherein the electronic device is a personal digital assistant (PDA), a player, a notebook computer, a digital camera, a display monitor, an automotive displayer, a tablet computer, a television, a global positioning system (GPS), an aviation displayer, a digital photo frame, a portable DVD displayer, or a cellular phone.

11. A system for displaying images, comprising:

a plurality of first lines;

a plurality of second lines interlaced with the first lines; and

a touch sensing circuit comprising a voltage storage unit for detecting whether a touch event has occurred and generating a corresponding voltage, wherein the voltage storage unit comprises;

a plurality of sensing cells disposed in a sensing array, wherein each of the sensing cells correspond to the interlaced first line and second line and comprises;

a first capacitor formed between the corresponding first line and the corresponding second line, wherein when the touch event has occurred in the corresponding sensing cell, a value of the first capacitor is changed; and

a first switch element having a first terminal coupled to the corresponding first line and a second terminal coupled to the corresponding second line;

a plurality of second capacitors respectively coupled to the first lines, each having a first terminal coupled to a ground terminal and a second terminal coupled to the corresponding first line;

a plurality of third capacitors respectively coupled to the second lines, each having a first terminal coupled to the ground terminal and a second terminal coupled to the corresponding second line;

a plurality of second switch elements respectively coupled to the first lines, each having a first terminal coupled to the corresponding first line and a second terminal; and

a plurality of switch units respectively coupled to the second lines, wherein when the voltage storage unit detects whether a touch event has occurred, the switch units are turned on sequentially in a first pre-determined order for providing an alternating current (AC) voltage to the second lines.

12. The system as claimed in claim 11, wherein each of the switch units comprises:

a third switch element having a first terminal coupled to the AC voltage and a second terminal coupled to the corresponding second line; and

a fourth switch element having a first terminal coupled to the ground terminal and a second terminal coupled to the corresponding second line,

wherein for the sensing cells coupled to the corresponding second line, when the voltage storage unit detects whether a touch event has occurred, the third switch element is turned on, and the fourth switch element is turned off for providing the AC voltage to the corresponding second line; and

wherein for the sensing cells coupled to the corresponding second line, when the voltage storage unit does not detect whether a touch event has occurred, the third switch element is turned off, and the fourth switch element is turned on for providing a voltage of the ground terminal to the corresponding second line.

13. The system as claimed in claim 11, wherein for each of the switch units, when the switch unit is turned on, the second switch elements are turned on sequentially in a second pre-determined order.

14. The system as claimed in claim 11, wherein each of the sensing cells further comprises a fourth capacitor coupled between the corresponding first line and the ground terminal.

15. The system as claimed in claim 11, wherein the touch sensing circuit further comprises an integration unit, coupled to the second terminal of the second switch element, for integrating voltages of the first lines and generating a plurality of integration signals.

16. The system as claimed in claim 15, wherein for the sensing cells coupled to the same second lines, when the voltage storage unit detects whether a touch event has occurred, the second switch elements are turned on sequentially in a second pre-determined order for providing the voltages of the first lines to the integration unit.

17. The system as claimed in claim 15, wherein the voltage storage unit further comprises a voltage amplifying unit, coupled to the integration unit, for receiving and amplifying the integration signals and generating output signals which indicate that whether a touch event has occurred in the sensing cells.

18. The system as claimed in claim 11 further comprising a touch panel, wherein the touch panel comprises the touch sensing circuit.

19. The system as claimed in claim 18 further comprises an electronic device, wherein the electronic device comprises a display panel for displaying images, and the system communicates with a user trough the touch panel.

20. The system as claimed in claim 19, wherein the electronic device is a personal digital assistant (PDA), a player, a notebook computer, a digital camera, a display monitor, an automotive displayer, a tablet computer, a television, a global positioning system (GPS), an aviation displayer, a digital photo frame, a portable DVD displayer, or a cellular phone.