Touch sensing apparatus and touch sensing method using the same

• US 9,377,910 B2
• Filed: 09/13/2013
• Issued: 06/28/2016
• Est. Priority Date: 04/22/2013
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.), Ulsan National Institute of Science and Technology
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.), Ulsan National Institute of Science and Technology
• Inventors: Ahn, Soon-Sung, Bien, Franklin, Kim, Jae-Joon, Heo, Sang-Hyune, Park, Kyeong-Hwan
• Primary Examiner(s): Giesy, Adam R
• Assistant Examiner(s): Heyi, Henok
• Application Number:
  US14/027,053
• Publication Number:
  US 20140313157A1
• Time in Patent Office: 1,019 Days
• Field of Search: None
• US Class Current: 1/1
• 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 touch sensing apparatus includes a touch screen panel including first electrodes along a first direction and second electrodes along a second direction crossing the first direction to form capacitances with the first electrodes, a driving circuit configured to supply a driving signal to the first electrodes; and a sensing circuit configured to detect output sensing signals from the second electrodes and recognize a touch input based on the output sensing signals. The sensing circuit includes a switching unit configured to modulate the output sensing signals by providing codes as respective input sensing signals to the second electrodes, an amplifying unit configured to amplify the modulated sensing signals, an analog-digital conversion unit configured to convert the amplified sensing signals into digital sensing signals, and a controller configured to demodulate the digital sensing signals and detect a touch input and its position from the demodulated sensing signals.

Claims

1. A touch sensing apparatus comprising:

a touch screen panel comprising driving electrodes along a first direction and sensing electrodes along a second direction crossing the first direction to form capacitances with the driving electrodes;

a driving circuit configured to supply a driving signal to the driving electrodes; and

a sensing circuit configured to detect output sensing signals from the sensing electrodes and recognize a touch input based on the output sensing signals,

wherein the sensing circuit comprises;

a switching unit configured to modulate the output sensing signals from the sensing electrodes by providing codes as respective input sensing signals to the sensing electrodes;

an amplifying unit configured to amplify the modulated sensing signals;

an analog-digital conversion unit configured to convert the amplified sensing signals into digital sensing signals; and

a controller configured to demodulate the digital sensing signals and detect a touch input and its position from the demodulated sensing signals,

wherein the switching unit comprises;

first switches respectively coupled between the sensing electrodes and code voltage sources; and

second switches respectively coupled between the sensing electrodes and the amplifying unit,

wherein the amplifying unit comprises;

a number of amplifiers corresponding to a number of groups each comprising ones of the sensing electrodes from which corresponding said output sensing signals are added; and

third switches coupled in parallel with respective said amplifiers, and

wherein the first switches and the third switches are configured to turn on concurrently.

2. The touch sensing apparatus of claim 1, wherein the switching unit is further configured to

divide the sensing electrodes into one or more groups each comprising two or more of the sensing electrodes,

modulate the output sensing signals by respectively providing orthogonal codes as the input sensing signals to the sensing electrodes included in each of the groups, and then

concurrently supply the modulated sensing signals included in a same one of the groups to an amplifier provided in the amplifying unit.

3. The touch sensing apparatus of claim 2, wherein the controller is further configured to separate the output sensing signals and detect the touch input by demodulating the modulated sensing signals for each group using the orthogonal codes provided as the respective input sensing signals.

4. The touch sensing apparatus of claim 2, wherein the amplifying unit comprises a corresponding one or more amplifiers respectively assigned to the groups.

5. The touch sensing apparatus of claim 1, wherein the switching unit is further configured to

divide the sensing electrodes into one or more groups each comprising 2ⁿ (n is a natural number) of the sensing electrodes, and

respectively provide 2ⁿ 2ⁿ-bit separable orthogonal codes as the input sensing signals to the sensing electrodes included in one group.

6. The touch sensing apparatus of claim 1,

wherein the first switches and the second switches are configured to alternately turn on, and

wherein the switching unit is further configured to

supply code voltages as the respective input sensing signals to the respective sensing electrodes using the first switches, and then

couple the respective sensing electrodes to the amplifying unit using the second switches.

7. The touch sensing apparatus of claim 1,

wherein the driving circuit is further configured to supply, to the driving electrodes, a driving signal that swings between first and second voltages, and

wherein the switching unit is further configured to

supply, to the respective sensing electrodes, code voltages corresponding to the codes when the first voltage is supplied to the driving electrodes, and

couple the sensing electrodes to the amplifying unit when the second voltage is supplied to the driving electrodes.

8. The touch sensing apparatus of claim 1,

wherein the switching unit is further configured to

add the output sensing signals from ones of the sensing electrodes to which separable ones of the codes are respectively provided, and

supply the added sensing signals to the amplifying unit.

9. The touch sensing apparatus of claim 8, wherein the third switches are configured to turn on when the codes are provided as the respective input sensing signals, and to turn off when the modulated sensing signals are supplied to the amplifying unit.

10. The touch sensing apparatus of claim 1, further comprising a multiplexing unit coupled between the amplifying unit and the analog-digital conversion unit.

11. A touch sensing method comprising:

dividing electrodes of a touch screen panel into one or more groups each comprising a plurality of the electrodes;

modulating sensing signals from sensing electrodes of the electrodes by respectively providing codes separable from one another as input sensing signals to the plurality of the electrodes included in each of the groups;

adding output sensing signals received from the plurality of the electrodes for each of the groups after the respectively providing of the codes;

separating the added sensing signals for each of the groups into the output sensing signals through demodulation using the codes; and

detecting a touch input applied to the touch screen panel using the separated sensing signals.

12. The touch sensing method of claim 11, wherein the respectively providing of the codes comprises respectively supplying, to the plurality of the electrodes included in each of the groups, code voltages corresponding to the codes.

13. The touch sensing method of claim 11, wherein the adding of the output sensing signals comprises:

respectively coupling the plurality of the electrodes included in each of the groups to code voltage sources having code voltages corresponding to the codes; and

coupling the plurality of the electrodes included in each of the groups to an output line after the code voltages are supplied to the respective electrodes.

14. The touch sensing method of claim 11, further comprising:

amplifying the added sensing signals for each of the groups; and

converting the amplified sensing signals into digital signals.