TOUCH PANEL

• US 20130027333A1
• Filed: 07/26/2012
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: NAGATA, Koji
• Granted Patent: US 9,069,424 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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 3/044 by capacitive means
• 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

Provided is a touch panel with improved anti-noise performance. A continuous drive pulse train is input to a plurality of scanning electrodes for each one scanning period in turns, and a detection pulse train generated at detection electrodes which intersects the scanning electrodes is detected. The detection pulse train is sampled at different intervals to generate a plurality of data sequences. The plurality of data sequences may be generated from the detection pulse train over a plurality of frame periods. A signal strength of each frequency component is compared between the frequency spectra of the plurality of data sequences, and a frequency spectrum in which frequency components having different strengths have been corrected is generated. A detection signal is generated from the corrected frequency spectrum.

Claims

1. A touch panel, comprising:

a plurality of scanning electrodes;

a plurality of detection electrodes which intersect the plurality of scanning electrodes;

first means for inputting a continuous drive pulse train to the plurality of scanning electrodes for each one scanning period in turns;

second means for extracting pulses at different intervals from a continuous detection pulse train detected by the plurality of detection electrodes, and for generating at least two data sequences;

third means for generating a frequency spectrum of each of the at least two data sequences;

fourth means for comparing a signal strength of each frequency component between the frequency spectra of the at least two data sequences, and for generating a frequency spectrum in which frequency components having different strengths have been corrected; and

fifth means for generating a detection signal from the frequency spectrum generated by the fourth means.

2. The touch panel according to claim 1, wherein the third means generates the frequency spectrum from the each of the at least two data sequences over a plurality of frame periods.

3. The touch panel according to claim 1, wherein the third means performs Fourier transform on each of the at least two data sequences to generate frequency spectra of the at least two data sequences, respectively.

4. The touch panel according to claim 1, wherein the fourth means compares a signal strength of each frequency component between the frequency spectra of the at least two data sequences, and adopts, as the signal strength of the frequency components having different strengths, one of a lowest value of the signal strength and an average value of the signal strength between frequency components of the frequency spectra of the at least two data sequences.

5. The touch panel according to claim 1, wherein the fifth means performs inverse Fourier transform on the frequency spectrum generated by the fourth means to generate a detection signal.

6. The touch panel according to claim 1, wherein the intervals of extracting a pulse from the continuous detection pulse train detected at the plurality of detection electrodes are adjustable for each of the at least two data sequences.

7. The touch panel according to claim 1, wherein the at least two data sequences comprise two data sequences of a first data sequence and a second data sequence.

8. The touch panel according to claim 7, wherein the third means performs Fourier transform on the first data sequence and the second data sequence to generate the frequency spectrum of the first data sequence and the frequency spectrum of the second data sequence.

9. The touch panel according to claim 7, wherein the fourth means compares the signal strength of each frequency component between the frequency spectrum of the first data sequence and the frequency spectrum of the second data sequence, and adopts, as the signal strength of the frequency components having different strengths, a value of a lower signal strength of the frequency components of the frequency spectrum of the first data sequence and the frequency components of the frequency spectrum of the second data sequence.

10. The touch panel according to claim 1, wherein the touch panel does not comprise a shielding electrode on a surface thereof on a display panel side, the touch panel being mountable on the display panel.