Touch input device

• US 8,773,401 B2
• Filed: 09/29/2011
• Issued: 07/08/2014
• Est. Priority Date: 05/02/2011
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: SHIH Hua Technology Limited
• Inventors: Shih, Po-Sheng, Cheng, Chien-Yung
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Ritchie, Darlene M
• Application Number:
  US13/248,511
• Publication Number:
  US 20120280946A1
• Time in Patent Office: 1,013 Days
• Field of Search: 345173-175, 345/178, 345/88, 345/211, 345/589, 738/620.41, 324/686, 428/114, 428/292.1, 248/346.5, 178 1801- 2004
• US Class Current: 345/178
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch input device includes a touch panel, a driving and sensing circuit, a data memory, and a processor. The touch panel is adapted to receive a touch trace including at least one touch point. The driving and sensing circuit is adapted to drive the touch panel and detect actual signal value V_i. The data memory is adapted to store a look up table including a plurality of position coordinates and a plurality of calibrating rules f each corresponding to each of the position coordinates. Each of the calibrating rules f can be used to convert actual signal value V_0i of the touch point of a basic contact area A₀ to a standard signal value V_s. The processor is adapted to calculate the position coordinate and calibrate the actual signal value V_i of the at least one touch point to a calibrated signal value V′_i.

Claims

1. A touch input device comprising:

a touch panel receiving a touch trace formed by touching the touch panel, wherein the touch trace comprises at least one touch point;

a driving and sensing circuit driving the touch panel and sensing an actual signal value V_i of the at least one touch point, wherein if an actual contact area A_i of the at least one touch point is a basic contact area A_o, the actual signal value V_i of the at least one touch point is V_oi;

a data memory storing a look up table comprising a plurality of position coordinates on the touch panel and a plurality of calibrating rules f, each of the calibrating rules f corresponding to each of the position coordinates, and used to convert V_oi of the at least one touch point of the basic contact area A_o in the position coordinate to a standard signal value Vs, wherein the converting process is represented by f(V_oi)=V_s, the calibrating rules f performing a function of V_oi; and

a processor calculating the position coordinate and calibrating the actual signal value V_i of the at least one touch point to a calibrated signal value V′

_i by a corresponding calibrating rule f, wherein the calibrating process is represented by f(V_i)=V<sub>′

i</sub>, and wherein the calibrated signal value (V<sub>′

i</sub>) is related to the actual contact area of the at least one touch point, and unrelated to the position coordinate of the at least one touch point.

2. The touch input device of claim 1 further comprising an analog to digital converter converting the actual signal value V_i from an electrical signal to a digital signal value.

3. The touch input device of claim 1, wherein the processor calibrates a plurality of the actual signal values V_i from an electrode of the touch panel corresponding to the at least one touch point and its adjacent electrodes.

4. The touch input device of claim 1, wherein the touch panel is a multi-touch resistive touch panel.

5. The touch input device of claim 4, wherein the multi-touch resistive touch panel comprises at least one first electrode plate comprising a first conductive layer and a plurality of first electrodes, a second electrode plate comprising a second conductive layer and a plurality of second electrodes, and a plurality of dot spacers disposed between the first conductive layer and the second conductive layer, each of the first conductive layer and the second conductive layer being a transparent and anisotropic conductive film.

6. The touch input device of claim 5, wherein the transparent and anisotropic conductive film is a carbon nanotube film comprising a plurality of carbon nanotubes.

7. The touch input device of claim 6, wherein the carbon nanotube film is a carbon nanotube drawn film formed by drawing a carbon nanotube array.

8. The touch input device of claim 7, wherein uniform gaps are defined between the carbon nanotubes, and a width of each of the gaps is in a range from about 1 nanometer to about 10 micrometers.

9. The touch input device of claim 7, wherein a majority of the plurality of carbon nanotubes in the carbon nanotube film extend substantially along a same direction and is parallel to a surface of the carbon nanotube film.

10. The touch input device of claim 9, wherein an end of each carbon nanotube in the majority of the plurality of carbon nanotubes is joined to another end of an adjacent carbon nanotube arranged substantially along the same direction by van der Waals attractive force.

11. The touch input device of claim 9, wherein the plurality of first electrodes is separately located on and electrically connected with at least one end along a second direction of the first conductive layer;

the plurality of second electrodes is separately located on and electrically connected with at least one end along a first direction of the second conductive layer;

the first direction is substantially perpendicular to the second direction;

the majority of the plurality of carbon nanotubes in the first conductive layer integrally extend along the first direction and is electrically connected with the plurality of first electrodes; and

the majority of the plurality of carbon nanotubes in the second conductive layer integrally extends along the second direction and is electrically connected with the plurality of second electrodes.

12. The touch input device of claim 11, wherein the first direction is an X direction, the second direction is a Y direction;

V_0i is represented by;

V_0i=(V_0ix, V_0iy), wherein V_0ix represents signal values in the X direction, and V_0iy represents signal values in the Y direction;

V_s is represented by;

V_s=(V_sx, V_sy), wherein V_sx represents the standard signal value in the X direction, and V_sy represents the standard signal value in the Y direction; and

f(V_0i)=V_s comprises f(V_0ix)=V_sx and f(V_0iy)=V_sy.

13. The touch input device of claim 12, wherein each of the calibrating rules f is represented by f(V_0i)=L_0i×

V_0i=V_s, wherein L_0i is a coefficient of V_0i for converting into V_s, and L_0i is represented by L_0i=(L_0ix, L_0iy), L_0ix is the coefficient in the X direction, and L_0iy is the coefficient in the Y direction; and

L_0ix×

V_0ix=V_sx, and L_0iy×

V_0iy=V_sy.

14. The touch input device of claim 1, wherein the data memory is adapted to store an operating rule g that converts the calibrated signal value V′

_i to a one-dimensional calibrated value V′

_i-total, the converting process is represented by g(V′

_ix, V′

_iy)=V′

_i-total, wherein the calibrated signal value V′

_i is represented by V′

_i=(V′

_ix, V′

_iy), V′

_ix represents the calibrated signal value in the X direction and V′

_iy represents the calibrated signal value in the Y direction.

15. The touch input device of claim 14, wherein V′

_i-total is a sum of the calibrated signal value in the X direction V′

_ix and the calibrated signal value in the Y direction V′

_iy represented by V′

_i-total=V′

_ix+V′

_iy.

16. The touch input device of claim 15, wherein the one-dimensional calibrated value V′

_i-total is further restricted to an output signal value V_i-output, the restricted process comprises the following steps;

defining an output range (V_down, V_up) and an output digit t, wherein t is a natural number;

judging whether the one-dimensional calibrated value V′

_i-total is in the output range (V_down, V_up);

if the one-dimensional calibrated value V′

_i-total is in the range, outputting the output signal value V_i-output as