Touch detection device, display device having touch detection function, electronic unit, and touch detection circuit

• US 8,736,563 B2
• Filed: 04/25/2011
• Issued: 05/27/2014
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Inventors: Noguchi, Koji, Kida, Yoshitoshi
• Primary Examiner(s): Snyder, Adam J
• Application Number:
  US13/093,057
• Publication Number:
  US 20110267296A1
• Time in Patent Office: 1,128 Days
• Field of Search: 345/173, 345/174, 178/18.01, 178/18.02, 178/18.06
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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

Abstract

A touch detection device includes: a plurality of drive electrodes; a plurality of detection electrodes intersecting the plurality of drive electrodes, and each outputting, in response to driving of each of the drive electrodes, a series of detection signals; a signal correction section determining a reference based on the detection signals, and subtracting the determined reference from each of the detection signals; and a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section.

Claims

1. A touch detection device, comprising:

a plurality of drive electrodes arranged side-by-side and extending in a direction;

a plurality of detection electrodes arranged side-by-side, extending to intersect the plurality of drive electrodes, allowing an electrostatic capacitance to be formed at each of intersections of the plurality of drive electrodes and the plurality of detection electrodes, and each outputting a detection signal in response to driving of each of the drive electrodes;

a signal correction section correcting the detection signals outputted from the plurality of detection electrodes, through determining a reference based on the detection signals, and through subtracting the determined reference from each of the detection signals; and

a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section,

wherein the signal correction section

determines, for each of the plurality of detection electrodes, a representative value of an absolute value of a sum of a touch component and a noise component both contained in the detection signal outputted from the corresponding detection electrode in a predetermined period,

selects a smallest representative value from the plurality of representative values, and

uses, as the reference, a representative value of a detection signal which has brought the selected smallest representative value.

2. The touch detection device according to claim 1, wherein the signal correction section

calculates, for each of the plurality of detection electrodes, a time-average of the absolute value of the sum of the touch component and the noise component both contained in the detection signal outputted from the corresponding detection electrode in the predetermined period, as the representative value,

selects a smallest time-average from the plurality of time-averages obtained, and

uses, as the reference, a time-average of a detection signal which has brought the selected smallest time-average.

3. The touch detection device according to claim 1, wherein the signal correction section

determines, for each of the plurality of detection electrodes, a minimum of absolute value of the sum of the touch component and the noise component both contained in the detection signal outputted from the corresponding detection electrode in the predetermined period, as the representative value,

selects a smallest minimum from the plurality of minimums obtained, and

uses, as the reference, a detection signal which has brought the smallest minimum.

4. The touch detection device according to claim 1, wherein the signal correction section subtracts the current reference from each of the current detection signals, the current reference being determined from the current detection frame, the current detection signals being obtained from the respective detection electrodes in the current detection frame.

5. The touch detection device according to claim 4, wherein the signal correction section temporarily holds the current detection signals obtained from the respective detection electrodes.

6. The touch detection device according to claim 1, wherein the signal correction section subtracts the preceding reference from each of the current detection signals, the preceding reference being determined from the preceding detection frame, the current detection signals being obtained from the respective detection electrodes in the current detection frame.

7. A display device having a touch detection function, the display device comprising:

a display section performing display based on an image signal;

a plurality of drive electrodes arranged side-by-side and extending in a direction;

a plurality of detection electrodes arranged side-by-side, extending to intersect the plurality of drive electrodes, allowing an electrostatic capacitance to be formed at each of intersections of the plurality of drive electrodes and the plurality of detection electrodes, and each outputting a detection signal in response to driving of each of the drive electrodes;

a signal correction section correcting the detection signals outputted from the plurality of detection electrodes, through determining a reference based on the detection signals, and through subtracting the determined reference from each of the detection signals; and

a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section,

wherein the signal correction section

determines, for each of the plurality of detection electrodes, a representative value of an absolute value of a sum of a touch component and a noise component both contained in the detection signal outputted from the corresponding detection electrode in a predetermined period,

selects a smallest representative value from the plurality of representative values, and

uses, as a reference, a representative value of a detection signal which has brought the selected smallest representative value.

8. An electronic unit, comprising:

a touch detection device; and

a control section performing an operation control that utilizes the touch detection device,

wherein the touch detection device includes;

a plurality of drive electrodes arranged side-by-side and extending in a direction;

a plurality of detection electrodes arranged side-by-side, extending to intersect the plurality of drive electrodes, allowing an electrostatic capacitance to be formed at each of intersections of the plurality of drive electrodes and the plurality of detection electrodes, and each outputting a detection signal in response to driving of each of the drive electrodes;

a signal correction section correcting the detection signals outputted from the plurality of detection electrodes, through determining a reference based on the detection signals, and through subtracting the determined reference from each of the detection signals; and

a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section,

wherein the signal correction section

determines, for each of the plurality of detection electrodes, a representative value of an absolute value of a sum of a touch component and a noise component both contained in the detection signal outputted from the corresponding detection electrode in a predetermined period,

selects a smallest representative value from the plurality of representative values, and

uses, as a reference, a representative value of a detection signal which has brought the selected smallest representative value.

9. A touch detection circuit, comprising:

a signal correction section correcting detection signals through determining a reference based on the detection signals and through subtracting the determined reference from each of the detection signals, the detection signals being outputted from a plurality of detection electrodes, the plurality of detection electrodes being arranged side-by-side, extending to intersect a plurality of drive electrodes arranged side-by-side and extending in a direction, allowing an electrostatic capacitance to be formed at each of intersections of the plurality of drive electrodes and the plurality of detection electrodes, and each outputting the detection signal in response to driving of each of the drive electrodes; and

a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section;

wherein the signal correction section

determines, for each of the plurality of detection electrodes, a representative value of an absolute value of a sum of a touch component and a noise component both contained in the detection signal outputted from the corresponding detection electrode in a predetermined period,

selects a smallest representative value from the plurality of representative values, and

uses, as a reference, a representative value of a detection signal which has brought the selected smallest representative value.

10. A touch detection device, comprising:

a plurality of drive electrodes;

a plurality of detection electrodes intersecting the plurality of drive electrodes, and each outputting, in response to driving of each of the plurality of drive electrodes, a series of detection signals;

a signal correction section determining a reference based on the detection signals, and subtracting the determined reference from each of the detection signals; and

a detecting section detecting an external proximity object based on corrected detection signals provided from the signal correction section,

wherein the signal correction section

determines, for each of the plurality of detection electrodes, a representative value of an absolute value of a sum of a touch component and a noise component both contained in the detection signal outputted from the corresponding detection electrode in a predetermined period,

selects a smallest representative value from the plurality of representative values, and

uses, as a reference, a representative value of a detection signal which has brought the selected smallest representative value.

11. The touch detection device according to claim 10, wherein the signal correction section

calculates, for each of the plurality of detection electrodes, a time-average of a variation component having the sum of the touch component and the noise component both contained in the each of the detection signals outputted from the corresponding detection electrode in the predetermined period, as the representative value,

selects a smallest time-average from the plurality of time-averages obtained, and uses, as the reference, a time-average of a detection signal which has brought the selected smallest time-average.

12. The touch detection device according to claim 10, wherein the signal correction section

determines, for each of the plurality of detection electrodes, a minimum of absolute value of a variation component having the sum of the touch component and the noise component both contained in the detection signal outputted from the corresponding detection electrode in the predetermined period, as the representative value,

selects a smallest minimum from the plurality of minimums obtained, and

uses, as the reference, a detection signal which has brought the smallest minimum.