COORDINATE INPUT DEVICE, AND ELECTRONIC DEVICE

• US 20130321341A1
• Filed: 02/15/2012
• Published: 12/05/2013
• Est. Priority Date: 02/22/2011
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Takahama, Kengo
• Granted Patent: US 9,195,356 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/044 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

A coordinate input device of the present invention includes: an M-sequence generator (12); a drive electrode driving circuit (13); and a receiving electrode selecting circuit (14) which receives a value corresponding to a coupling capacitance, an inputted coordinate position being detected in accordance with the value received by the receiving electrode selecting circuit (14), a receiving electrode group being divided into two blocks, and a first detecting section (15) and a second detecting section (16) being provided so as to correspond to the respective two blocks.

Claims

1. A coordinate input device comprising:

a drive electrode group composed of drive electrodes which are arranged on a substrate at regular intervals;

a receiving electrode group composed of receiving electrodes which are arranged at regular intervals so as to be insulated from and intersect with the drive electrodes;

a pseudorandom signal generating means for generating a pseudo-random signal having a pulse-like autocorrelation function;

a drive electrode driving circuit which sequentially applies, to each of the drive electrodes, a voltage synchronized with a cycle of the pseudorandom signal;

a receiving electrode selecting circuit which is connected to the receiving electrode group and receives a value corresponding to a coupling capacitance obtained by capacitive coupling between the drive electrode group and the receiving electrode group; and

detecting means for detecting an inputted coordinate position in accordance with the value received by the receiving electrode selecting circuit,

the receiving electrode group being divided into N blocks (N is a positive number not less than two), and the N blocks being provided with the respective detecting means.

2. The coordinate input device as set forth in claim 1, wherein the drive electrode driving circuit applies a given voltage to each of the drive electrodes in a case where the pseudorandom signal is at a high level.

3. The coordinate input device as set forth in claim 1, wherein:

the drive electrode driving circuit applies a given voltage to each of the drive electrodes in a case where the pseudorandom signal is at a high level; and

the drive electrode driving circuit applies, to each of the drive electrodes, a voltage with reverse polarity to the given voltage in a case where the pseudorandom signal is at a low level.

4. A coordinate input device as set forth in claim 1, further comprising:

a pseudorandom signal reconstructing means for reconstructing an output from each of the detecting means to an original pseudorandom signal,

the pseudorandom signal reconstructing means reconstructing, by time-sharing, the output from the each of the detecting means, the output being sequentially outputted for each of the N blocks.

5. The coordinate input device as set forth in claim 4, wherein:

the detecting means each include;

a coupling capacitance measuring circuit which measures the coupling capacitance received by the receiving electrode selecting circuit; and

a storage section which temporarily stores, as a detection result, the coupling capacitance measured by the coupling capacitance measuring circuit, and

the detection result is supplied to the pseudorandom signal reconstructing means while the N blocks, each corresponding to the detection result, are being switched to one another, the detection result being stored in the storage section of the each of the detecting means in time series.

6. A coordinate input device as set forth in claim 1, further comprising:

a pseudorandom signal reconstructing means for reconstructing an output from each of the detecting means to an original pseudorandom signal,

the pseudorandom signal reconstructing means reconstructing, in parallel, the output from the each of the detecting means, the output being outputted for each of the N blocks.

7. An electronic device comprising:

a coordinate input device, the coordinate input device comprising;

a drive electrode group composed of drive electrodes which are arranged on a substrate at regular intervals;

a receiving electrode group composed of receiving electrodes which are arranged at regular intervals so as to be insulated from and intersect with the drive electrodes;

a pseudorandom signal generating means for generating a pseudo-random signal having a pulse-like autocorrelation function;

a drive electrode driving circuit which sequentially applies, to each of the drive electrodes, a voltage synchronized with a cycle of the pseudorandom signal;

a receiving electrode selecting circuit which is connected to the receiving electrode group and receives a value corresponding to a coupling capacitance obtained by capacitive coupling between the drive electrode group and the receiving electrode group; and

detecting means for detecting an inputted coordinate position in accordance with the value received by the receiving electrode selecting circuit,

the receiving electrode group being divided into N blocks (N is a positive number not less than two), and the N blocks being provided with the respective detecting means.