CAPACITIVE TOUCH PANEL AND METHOD FOR DETECTING TOUCHED INPUT POSITION ON THE SAME

• US 20100283752A1
• Filed: 04/28/2010
• Published: 11/11/2010
• Est. Priority Date: 05/07/2009
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: MAEDA, Takami
• Application Number:
  US12/769,155
• Publication Number:
  US 20100283752A1
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 capacitive touch panel of the present invention is characterized by including a plurality of detection period setting section 18 to 20 and electrode range setting section 21. Detection is performed by setting a detection period for electrodes 3 and 4, which are situated in a range previously determined with reference to the electrodes 3 and 4 where a touch input is detected, so as to become larger than a detection period achieved before detection of the touch input.

Claims

1. A capacitive touch panel, comprising:

a detection surface;

a first electrode provided on the detection surface and including a plurality of electrodes arranged in parallel;

a second electrode provided on the detection surface and including a plurality of electrodes arranged in parallel along a direction crossing the first electrode;

a touch input detection section detecting a touch input on the detection surface made by a predetermined coordinate pointer in accordance with a change in an electrostatic capacitance between the first and second electrodes;

a detection period setting section that sets a period for selecting the first or second electrode so as to set a substantial detection period; and

a control section that controls the detection period set by the detection period setting section in accordance with a result of detection performed by the touch input detection section;

wherein the control section sets the detection period for an electrode from which the touch input is detected, among the first and second electrodes, longer than the detection period set theretofore.

2. The capacitive touch panel according to claim 1, wherein the control section selects a reference electrode from the first and second electrodes according to the result of detection;

selects an electrode, from the first and second electrodes, situated in a predetermined range from the reference electrode; and

also sets the detection period to a detection period longer than the detection period set theretofore with regard to the reference electrode and the selected electrode.

3. The capacitive touch panel according to claim 1, further comprising:

an input determination section that determines that the touch input is successfully detected or unsuccessfully detected, by comparing the result of detection performed by the touch input detection section with a preset first threshold value, wherein, when the input determination section determines that the touch input is successfully detected, the control section changes the first threshold value to a larger second threshold value and performs subsequent operation for detecting a touch input by means of the second threshold value.

4. The capacitive touch panel according to claim 1, wherein the control section sets the detection period to T1 in a state where the touch input is determined to be unsuccessfully detected and sets the detection period for the electrode, where the touch input is determined to be successfully detected, to T2 that is longer than T1 when the touch input is determined to be successfully detected.

5. The capacitive touch panel according to claim 1, wherein the input determination section has a third threshold value that is smaller than the second threshold value;

compares a detection value acquired after the touch input is determined to be successfully detected with the third threshold value; and

determines the touch input to be unsuccessfully detected when the detection value is less than the third threshold value.

6. The capacitive touch panel according to claim 1, wherein the control section selects, from the first and second electrodes, one located within a range except a predetermined range from the reference electrode, in accordance with the result of detection;

and further sets the detection period for the selected electrode to T3 that is shorter the detection period set theretofore.

7. The capacitive touch panel according to claim 1, wherein the control section again sets the detection period to T1 when a touch input is determined to be unsuccessfully detected at any of the electrodes for a preset period of time or more after the input determination section has determined that the touch input is successfully detected.

8. The capacitive touch panel according to claim 1, wherein the control section changes the predetermined range according to a direction and a speed of movement of a position where the touch input is detected and performs subsequent operation for detecting a touch input by means of the changed range.

9. The capacitive touch panel according to claim 1, wherein the second electrode is arranged at equal pitches in a direction orthogonal to the first electrode, and the control section sets the predetermined range for each of the first electrode and the second electrode independently.

10. The capacitive touch panel according to claim 1, wherein the control section sets the detection periods T1, T2, and T3 for each of the first electrode and the second electrode independently.

11. A capacitive touch panel comprising:

a coordinate input detection panel including first electrodes arranged parallel to each other and second electrodes arranged parallel to a direction orthogonal to the first electrodes;

detection section that detects a change in electrostatic capacitance of the electrodes resulting from a coordinate pointer touching the first electrodes or the second electrodes in accordance with a change in frequency of an oscillation circuit;

input determination section for determining, from a plurality of detection values output from the detection section, whether a touch input is successfully or unsuccessfully detected;

detection period setting section that sets a detection period for the first or second electrodes;

control section for changing detection sensitivity for the first or second electrodes by changing settings of the detection period setting section;

a specifying section specifying a reference electrode, from the plurality of detection values from electrodes where a touch input is detected, for a case of determination of a preset range; and

electrode range setting section that sets electrodes in the range with reference to the specified electrode, wherein the control section performs control operation such that detection operation is performed while enhancing detection sensitivity of the electrode set by the electrode range setting section, on the basis of an electrode where the touch input is detected among the first and second electrodes.

12. The capacitive touch panel according to claim 11, wherein the range is stored, with reference to the reference electrode, as a unit based on an arrangement pitch of the first or second electrodes.

13. The capacitive touch panel according to claim 11, wherein the electrode range setting section sets, on the basis of the range, electrode identification information independently on a direction of arrangement of the first electrodes and a direction of arrangement of the second electrodes.

14. The capacitive touch panel according to claim 11, wherein the control section changes the range according to a direction and a speed of movement of the position of the touch input determined from coordinates of a plurality of touch input positions and controls the detection section such that the touch detection operation is performed by setting the electrode identification information based on the changed range in the electrode range setting section.

15. The capacitive touch panel according to claim 11, wherein the input determination section further has, as a threshold value for determining that a touch input is unsuccessfully detected, a third threshold value that is smaller than the second threshold value;

compares the third threshold value with a detection value acquired after the touch input is determined to be successfully detected; and

determines that the touch is unsuccessfully detected when the detection value is less than the third threshold value.

16. The capacitive touch panel according to claim 11, wherein the second detection period setting section sets different detection period values for the first or second electrodes situated in the range, according to the preset range.

17. A touch input position detection method for a capacitive touch panel having a coordinate input detection panel including first electrodes arranged parallel to each other and second electrodes arranged parallel to each other along a direction orthogonal to the first electrodes, the method comprising:

performing operation for detecting a touch input when a touch input is unsuccessfully detected by setting a preset first detection period in the plurality of electrodes; and

performing touch input detection operation after detection of the touch input by setting a second detection period longer than the first detection period in an electrode, among the first and second electrodes, previously set on the basis of a positional relationship with coordinates of a position where the touch input is detected.

18. The touch input position detection method for a capacitive touch panel according to claim 17, wherein touch detection operation is performed by setting a third detection period shorter than the first detection period in electrodes except the electrode previously set on the basis of the positional relationship with the coordinates of the position where the touch input is detected.