TOUCH DETECTION DEVICE, DISPLAY DEVICE HAVING TOUCH DETECTION FUNCTION, ELECTRONIC UNIT, AND TOUCH DETECTION CIRCUIT

• US 20140225866A1
• Filed: 04/15/2014
• Published: 08/14/2014
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Inventors: NOGUCHI, Koji, KIDA, Yoshitoshi
• Granted Patent: US 9,354,745 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 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 drive electrodes, allowing an electrostatic capacitance to be formed at each of intersections of the drive electrodes and the 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 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 drive electrodes function as a plurality of display horizontal lines for the display section by being supplied with a display drive signal, and function as a plurality of detection horizontal lines for detecting the external proximity object by being supplied with a touch detection signal for generating the detection signal, and

a touch detection by one detection horizontal line using one drive electrode, and a display by pixels corresponding to one display horizontal line using the one drive electrode are performed for each of the drive electrodes sequentially.

2. The display device having a touch detection function according to claim 1, further comprising

a drive electrode driver supplying the display drive signal and the touch detection signal to the drive electrodes,

wherein the drive electrode driver selects one of the drive electrodes as a target being supplied with the touch detection signal when detecting the external proximity object by the plurality of detection horizontal lines.

3. The display device having a touch detection function according to claim 1, wherein the signal correction section calculates, for each of the detection electrodes, a time-average of 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, 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.

4. The display device having a touch detection function according to claim 1, wherein the signal correction section determines, for each of the detection electrodes, a minimum of 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, selects a smallest minimum from the plurality of minimums obtained, and uses, as the reference, a detection signal which has brought the smallest minimum.

5. The display device having a touch detection function 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.

6. The display device having a touch detection function according to claim 5, wherein the signal correction section temporarily holds the current detection signals obtained from the respective detection electrodes.

7. The display device having a touch detection function 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.