Touch Screen Apparatus

• US 20090135158A1
• Filed: 11/07/2008
• Published: 05/28/2009
• Est. Priority Date: 11/26/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Lee, Byoung-Jun, Lee, Jun-Pyo, Takahashi, Seiki
• Granted Patent: US 8,427,435 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

There is provided a touch screen apparatus capable of detecting the presence a touch action and a position in a touch region depending on a change in electrical energy of one node of a touch sensor. A touch screen apparatus according to the present invention includes a plurality of pixels for displaying images and a plurality of touch sensors. Each of the plurality of touch sensors includes a first node being provided an electrical energy; a sensor capacitor for changing the electric potential energy of the first node depending on presence a touch action; a first switch for providing a sensing signal to the touch line controlled by the electrical energy of the first node; and a second switch for providing the electrical energy to the first node.

Claims

1. A touch screen apparatus, comprising:

a touch line; and

a plurality of touch sensors,

wherein each of the plurality of touch sensors comprises;

a first node;

a sensor capacitor for changing an electrical energy of the first node depending on a touch action;

a first switch for providing a sensing signal to the touch line controlled by the electrical energy of the first node; and

a second switch for providing the electrical energy to the first node.

2. The touch screen apparatus as claimed in claim 1, further comprising a touch sensing unit for outputting a sensing voltage according to the sensing signal of the touch line.

3. The touch screen apparatus as claimed in claim 2, further comprising:

display elements having at least one of the touch sensors and at least one pixel for displaying an image are arranged in a matrix;

a plurality of touch lines extending in a first direction and connected to the touch sensors in the display elements arranged in the first direction; and

a plurality of sensing readers in the touch sensing unit that are each connected to one of the plurality of touch lines.

4. The touch screen apparatus as claimed in claim 3, wherein each of the plurality of sensing readers comprises:

an integration circuit for outputting an output voltage, wherein the voltage level of the output voltage depends on an amount of current in the sensing signal;

an amplifier for amplifying the output voltage of the integration circuit; and

an analog-to-digital converter for converting the amplified output voltage into a digital signal.

5. The touch screen apparatus as claimed in claim 1, further comprising a pixel having a liquid crystal capacitor in which a pixel electrode is used as a first electrode and a common electrode is used as a second electrode of the liquid crystal capacitor,

wherein a first electrode of the sensor capacitor is formed on the same plane as the pixel electrode to be connected to the first node, and the common electrode is used as a second electrode of the sensor capacitor.

6. The touch screen apparatus as claimed in claim 1, further comprising:

a reference voltage supply line supplied with a reference voltage and coupled with the first node through a reference capacitor.

7. The touch screen apparatus as claimed in claim 1, further comprising a plurality of gate lines each connected to one of the plurality of touch sensors, the plurality of gate lines sequentially receiving a gate turn-on voltage,

wherein the first switch is controlled by a first gate line, the second switch is controlled by a second gate line that receives the gate turn-on voltage after the first gate line, and the first switch is connected to the first node and the touch line.

8. The touch screen apparatus as claimed in claim 7, wherein a first thin film transistor (TFT) is used as the first switch, a gate terminal of the first TFT is connected to the first gate line, a source terminal of the first TFT is connected to the first node, and a drain terminal of the first TFT is connected to the touch line, and

wherein a second TFT is used as the second switch, a gate terminal of the second TFT is connected to the second gate line, a source terminal of the second TFT is connected to a reference voltage supply line supplied with a reference voltage, and a drain terminal of the second TFT is connected to the first node.

9. The touch screen apparatus as claimed in claim 1, further comprising a sensing voltage supply line supplied with a sensing voltage,

wherein the first switch is connected to the sensing voltage supply line and the touch line, and the sensing voltage is applied as the sensing signal to the touch line depending on the electrical energy of the first node.

10. The touch screen apparatus as claimed in claim 9, further comprising:

a plurality of gate lines respectively connected to the plurality of touch sensors; and

a reference capacitor connected to the first gate line and the first node.

11. The touch screen apparatus as claimed in claim 10, wherein the first switch is controlled by the electrical energy of the first node, and the second switch is controlled by the second gate line which receives the gate turn-on voltage after the first gate line.

12. The touch screen apparatus as claimed in claim 11, wherein a first TFT is used as the first switch, a gate terminal of the first TFT is connected to the first node, a source terminal of the first TFT is connected to the sensing voltage supply line, and a drain terminal of the first TFT is connected to the touch line, and

wherein a second TFT is used as the second switch, a gate terminal of the second TFT is connected to the second gate line, a source terminal of the second TFT is connected to the first gate line, and a drain terminal of the second TFT is connected to the first node,

the first TFT being larger in size than the second TFT.

13. The touch screen apparatus as claimed in claim 11, further comprising a reference voltage supply line supplied with a reference voltage,

wherein a second TFT is used as the second switch, a gate terminal of the second TFT is connected to the second gate line, a source terminal of the second TFT is connected to the reference voltage supply line, and a drain terminal of the second TFT is connected to the first node.

14. A touch screen apparatus, comprising:

a touch line;

first and second lines;

first and second gate lines sequentially supplied with a gate turn-on voltage; and

a plurality of touch sensors,

wherein each of the plurality of touch sensors comprises;

a first node;

a sensor capacitor connected to the first node and the first line;

a reference capacitor connected to the first node and the second line;

a first switch for connecting the first node and the touch line controlled by a signal provided to the first gate line; and

a second switch for connecting the first node and the second line controlled by a signal provided to the second gate line.

15. The touch screen apparatus as claimed in claim 14, further comprising a pixel including a liquid crystal capacitor having a pixel electrode, a liquid crystal layer and a common electrode,

wherein the common electrode is used as the first line.

16. The touch screen apparatus as claimed in claim 15, wherein a storage line or a reference voltage supply line is used as the second line, and the reference voltage supply line is supplied with a reference voltage that is lower than a voltage applied to the common electrode.

17. The touch screen apparatus as claimed in claim 14, wherein a charge amount of the first node depends on a capacitance of the sensor capacitor,

the touch screen apparatus further comprising a sensing reader connected to the touch line whereby an output voltage level of the sensing reader depends on the charge amount of the first node.

18. The touch screen apparatus as claimed in claim 14, further comprising:

a lower substrate having a first electrode of the sensor capacitor formed thereon; and

an upper substrate having a second electrode of the sensor capacitor formed thereon,

wherein a distance between the first and the second electrodes of the sensor capacitor is changed by a touch action.

19. A touch screen apparatus, comprising:

a touch line;

a plurality of touch sensors;

a first line supplied with a common voltage;

a second line supplied with a sensing voltage;

first and second gate lines sequentially supplied with a gate turn-on voltage; and

a third line,

wherein each of the plurality of touch sensors comprises;

a first node;

a sensor capacitor connected to the first node and the first line;

a reference capacitor connected to the first node and the first gate line;

a first switch for connecting the second line and the touch line controlled by a voltage of the first node; and

a second switch for connecting the third line and the first node controlled by a signal provided to the second gate line.

20. The touch screen apparatus as claimed in claim 19, wherein the third line is a reference voltage line supplied with a reference voltage or the first gate line is used as the third line.

21. The touch screen apparatus as claimed in claim 20, wherein a gate turn-off voltage is used as the reference voltage.

22. The touch screen apparatus as claimed in claim 19, wherein first and second TFTs are respectively used as the first and second switches,

the touch screen apparatus further comprising a sensing reader outputting an output voltage wherein the voltage level of the output voltage depends on an amount of current that flows from the second line to the touch line through the first TFT.

23. The touch screen apparatus as claimed in claim 22, wherein the first TFT is larger in size than the second TFT.

24. The touch screen apparatus as claimed in claim 19, wherein the first gate line is used as the third line.