Method for detecting touch trace based on resistive touch panel

• US 8,624,872 B2
• Filed: 09/29/2011
• Issued: 01/07/2014
• Est. Priority Date: 04/29/2011
• 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:
  US13/248,447
• Publication Number:
  US 20120274601A1
• Time in Patent Office: 831 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, 156/296, 178 1801- 2004
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A method for detecting a touch trace is provided. A look up table, including a plurality of position coordinates and calibrating rules f corresponding to each of the plurality of position coordinates, is built. A touch trace including at least one touch point is received, wherein if an actual contact area A_i of the at least one touch point is a basic contact area A₀, an actual signal value V_i of the at least one touch point is V_0i. Each of the calibrating rules f is to convert the value V_0i to a standard signal value V_s. Position coordinates of the at least one touch point are calculated, the actual signal value V_i under the actual contact area A_i is obtained; and the calibrating rule f corresponded is queried. The actual signal value V_i is calibrated to the calibrated signal value V′_i.

Claims

1. A method for detecting a touch trace based on a resistive touch panel, the method comprising:

building a look up table comprising a plurality of position coordinates and calibrating rules f corresponding to each of the plurality of position coordinates;

receiving a touch trace comprising 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 A₀, an actual signal value V_i of the at least one touch point is V_0i;

each of the calibrating rules f is used to convert the value V_0i of the at least one touch point of the basic contact area A₀ in the position coordinates to a standard signal value V_s, and the converting process is represented by f(V_0i)=V_s;

calculating a position coordinate of the at least one touch point, and obtaining the actual signal value V_i under the actual contact area A_i of the at least one touch point; and

querying the calibrating rule f corresponding to the position coordinate of the at least one touch point from the look up table;

calibrating the actual signal value V_i to a calibrated signal value V′

_i represented by f (V_i)=V′

_i; and

reflecting the actual contact areas A_i of the at least one touch point using the calibrated signal value V′

_i.

2. The method of claim 1, wherein the step of building the look up table comprises:

setting the base contact area A₀;

obtaining the V_0i of a plurality of touch points of the base contact area A₀, wherein V_0i is represented by V_0i=(V_0ix, V_0iy), V_0ix represents actual signal values in the X direction, and the V_0iy represents actual signal values in Y direction;

defining the standard signal value V_s, wherein V_s is represented by V_s=(V_sx, V_sy), V_sx represents the standard signal value in the X direction, and V_syrepresents standard signal value in the Y direction; and

building the calibrating rules f to convert V_0i to V_s, wherein f(V_0ix)=V_sx and f(V_0iy)=V_sy.

3. The method of claim 2, wherein the calibrating rules f reflect a ratio of the standard signal value V_s to the actual signal values V_0i represented by 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), wherein L_0ix×

V_0ix=V_sx, and L_0iy×

V_0iy=V_sy.

4. The method of claim 1, wherein the actual signal value V_i is the largest signal value detected from electrodes of the resistive touch panel.

5. The method of claim 1, wherein the actual signal value V_i is a plurality of signal values detected comprising and adjacent to the largest signal value.

6. The method of claim 5 further comprising calibrating the plurality of signal values detected.

7. The method of claim 1 further comprising a step of converting the calibrated signal value V′

_i to a one-dimensional calibrated value V′

_i-total by an operating rule g, 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.

8. The method of claim 7, wherein V′

_i-total is i a sum of the V′

_ix and V′

_iy represented by V′

_i-total=V′

_ix+V′

_iy.

9. The method of claim 8 further comprising restricting the one-dimensional calibrated value V′

_i-total to an output signal value V′

_i-output, wherein the restricted process comprises;

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

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

10. The method of claim 9, wherein the output signal value V_i-output reflects a displayed diameter D_i of the at least one touch point in the touch trace, the reflecting process comprises:

pre-defining a displayed diameter of a touch point as D₀, wherein the signal value of the touch point is the standard signal value V_s and the contact area of the touch point is the base contact area A₀;

confirming a corresponding rule k stored by the data memory between the displayed diameter D₀ of the standard signal value V_s and the displayed diameter D_i of the output signal value V_i-output, wherein the larger the output signal value V_i-output, the larger the displayed diameter D_i; and

calculating the displayed diameter D _i of the output signal value V_i-output according to the corresponding rule k.

11. The method of claim 10, wherein the corresponding rule k meets D_i=k(V_i-output, V_s, D₀)=(V_i-output/V_s)×

D₀.

12. The method of claim 1, further comprising displaying the touch trace according to the position coordinates and the calibrated signal value of the at least one touch point in the touch trace, wherein a trajectory of the touch trace is displayed according to the position coordinates of the at least one touch point in the touch trace;

and a size of the touch trace is displayed according to the calibrated signal value of the at least one touch point.

13. The method of claim 1, further comprising providing the resistive touch panel, wherein the 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;

wherein each of the first conductive layer and the second conductive layer is a transparent and anisotropic conductive film.

14. The method of claim 13, wherein the transparent and anisotropic conductive film is a carbon nanotube film comprising a plurality of carbon nanotubes.

15. The method of claim 14, wherein the carbon nanotube film is a carbon nanotube drawn film formed by drawing a carbon nanotube array.

16. The method of claim 15, wherein a majority of the carbon nanotubes in the carbon nanotube drawn film extend substantially along a same direction and parallel to a surface of the carbon nanotube drawn film.

17. The method of claim 16, wherein an end of each carbon nanotube in the majority of the carbon nanotubes is joined to another end of an adjacent carbon nanotube arranged substantially along the same direction by van der Waals attractive force.

18. The method of claim 16, wherein the plurality of first electrodes are 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 are 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 carbon nanotubes in the first conductive layer integrally extends along the first direction and is electrically connected with the plurality of first electrodes; and

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

19. A touch trace detection method comprising:

building a look up table comprising a plurality of position coordinates and calibrating rules f corresponding to each of the plurality of position coordinates;

receiving a touch trace comprising 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 A₀, an actual signal value V_i of the at least one touch point is V_0i;

each of the calibrating rules f is used to convert the value V_0i of the at least one touch point of the basic contact area A₀ in the position coordinates to a standard signal value V_s, and the converting process is represented by f(V_0i)=V_s;

calculating a position coordinate of the at least one touch point, and obtaining the actual signal value V_i under the actual contact area A_i of the at least one touch point; and

querying the calibrating rule f corresponding to the position coordinate of the at least one touch point from the look up table;

calibrating the actual signal value V_i to a calibrated signal value V′

_i represented by f (V_i)=V′

_i;

converting the calibrated signal value V′

_i to a one-dimensional calibrated value V_i-total by an operating rule g, the converting process is represented by g(V′

_ix, V′

_iy)=V′

_i-total,, and V′

_i-total is a sum of the V′

_ix and V′

_iy represented by V′

_i-total=V′

_ix+V′

_iy, 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;

restricting the one-dimensional calibrated value V′

_i-total to an output signal value V_i-output, wherein the restricting process comprises;

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

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

20. A method for detecting a touch trace based on a resistive touch panel, the method comprising:

building a look up table comprising a plurality of position coordinates and calibrating rules f corresponding to each of the plurality of position coordinates;

receiving a touch trace comprising 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 A₀, an actual signal value V_i of the at least one touch point is V_0i;

each of the calibrating rules f is used to convert the value V_0iof the at least one touch point of the basic contact area A₀ in the position coordinates to a standard signal value V_s, and the converting process is represented by f(V_0i)=V_s;

calculating a position coordinate of the at least one touch point, and obtaining the actual signal value V_i under the actual contact area A_i of the at least one touch point; and

querying the calibrating rule f corresponding to the position coordinate of the at least one touch point from the look up table;

calibrating the actual signal value V_i to a calibrated signal value V′

_i represented by f (V_i)=V′

_i;

reflecting the actual contact areas A, of the at least one touch point using the calibrated signal value V′

_I; and

displaying the touch trace according to the position coordinates and the calibrated signal value of the at least one touch point in the touch trace, wherein a trajectory of the touch trace is displayed according to the position coordinates of the at least one touch point in the touch trace;

and a size of the touch trace is displayed according to the calibrated signal value of the at least one touch point.