TOUCH PANEL SYSTEM AND ELECTRONIC DEVICE

• US 20140253508A1
• Filed: 10/18/2012
• Published: 09/11/2014
• Est. Priority Date: 10/25/2011
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yumoto, Manabu, Hamada, Hiroshi
• Granted Patent: US 8,994,692 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means
• 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

Provided is a touch panel system capable of reliably removing a wide variety of noises. The touch panel system (1p) includes a subtracting section (41a) which receives output signals from the sense lines (33) and finds differences between the capacitances in a direction in which each of drive lines (35) extends, as the differences in signal between the respective pairs of the sense lines (33) adjacent to each other. The subtracting section (41a) obtains a difference signal value between the sense lines adjacent to each other.

Claims

1. A touch panel system comprising,

a touch panel;

and

a touch panel controller for processing a signal supplied from the touch panel,

the touch panel including a sensor section, the sensor section being provided with a plurality of sense lines and detecting a touch operation performed with respect to the touch panel,

the touch panel controller including a subtracting section for (i) receiving signals from the sensor section and (ii) finding differences in signal between, among the sense lines, respective pairs of sense lines adjacent to each other,

the touch panel system further comprising;

drive lines provided so as to intersect the sense lines;

a drive line driving circuit for driving the drive lines in parallel; and

capacitances being formed between the sense lines and the drive lines,

the subtracting section receiving output signals from the sense lines, and finding differences between the capacitances on each of the drive lines in a direction in which the each of the drive lines extends, the differences being found as the differences in signal between the respective pairs of the sense lines adjacent to each other,

the touch panel system further comprising;

a decoding section for decoding the values of the differences between the capacitances, which differences are found by the subtracting section, the decoding being carried out in such a manner that an inner product of each of code sequences for driving the drive lines in parallel and each of difference output sequences of the sense lines, which difference output sequences correspond to the code sequences, is calculated, and

the subtracting section finding a first difference which is expressed by (Sn−

1)−

Sn and a second difference which is expressed by (Sn+1)−

Sn,

the first difference corresponding to a difference between (i) a signal of a sense line Sn which is selected from the plurality of sense lines and (ii) a signal of a sense line Sn−

1, which is one of two sense lines adjacent to the sense line Sn, the two sense lines being the sense line Sn−

1 and a sense line Sn+1 each of which is included in the plurality of sense lines,

the second difference corresponding to a difference between (i) the signal of the sense line Sn and (ii) a signal of the sense line Sn+1, which is the other one of the two sense lines.

2. The touch panel system as set forth in claim 1, further comprising:

a switch for switching an input to the subtracting section,

the two sense lines adjacent to the sense line Sn selected from the plurality of sense lines being connected to the switch, and

the sense line Sn selected from the plurality of sense lines being directly connected to the subtracting section.

3. The touch panel system as set forth in claim 1, wherein

the code sequences are orthogonal sequences or M sequences.

4. The touch panel system as set forth in claim 1, wherein:

the subtracting section includes a third analog-to-digital converting section for converting, into digital signals, analog signals supplied from the sense lines to the subtracting section; and

the subtracting section uses, in order to find the differences in signal between the respective pairs of the sense lines adjacent to each other, the digital signals obtained by the third analog-to-digital converting section.

5. The touch panel system as set forth in claim 1, wherein:

the subtracting section includes a fourth analog-to-digital converting section for converting, into digital signals, analog signals supplied from the sense lines to the subtracting section; and

the fourth analog-to-digital converting section converts, into digital signals, the differences in signal between the respective pairs of the sense lines adjacent to each other, the differences being found by the subtracting section with use of the analog signals.

6. The touch panel system as set forth in claim 4, wherein:

the subtracting section includes a total differential amplifier for finding, with use of the analog signals, the differences in signal between the respective pairs of the sense lines adjacent to each other.

7. The touch panel system as set forth in claim 1, further comprising:

a non-touch operation information storage section for storing a first distribution of differences between the capacitances which differences are decoded by the decoding section when no touch operation is performed; and

a calibration section for subtracting (i) the first distribution stored in the non-touch operation information storage section from (ii) a second distribution of differences between the capacitances which differences are decoded by the decoding section when a touch operation is performed, so as to calibrate the second distribution.

8. The touch panel system as set forth in claim 1, further comprising:

a judging section for determining the presence or absence of a touch operation based on a comparison of (i) the differences in signal between the respective pairs of the sense lines adjacent to each other which differences are found by the subtracting section and (ii) positive and negative threshold values.

9. The touch panel system as set forth in claim 8, wherein:

the judging section creates, based on the comparison of (i) the differences in signal between the respective pairs of the sense lines adjacent to each other which differences are found by the subtracting section and (ii) the positive and negative threshold values, an increase and decrease table which indicates, in ternary, a distribution of differences between signals of the sense lines, and the judging section converts the increase and decrease table into a binary image, so as to extract touch information therefrom.

10. The touch panel system as set forth in claim 1, further comprising a display device,

the touch panel being provided to a front surface of the display device.

11. The touch panel system as set forth in claim 10, wherein:

the display device is a liquid crystal display, a plasma display, an organic electroluminescence display, or a field emission display.

12. An electronic device comprising a touch panel system as set forth in claim 1.