TOUCHED POSITION SPECIFYING METHOD AND TOUCHED POSITION SPECIFYING CIRCUIT

• US 20160349923A1
• Filed: 08/12/2016
• Published: 12/01/2016
• Est. Priority Date: 06/27/2011
• 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: MIYAMOTO, Masayuki, IIZUKA, Kunihiko
• Granted Patent: US 9,898,136 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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 capacitance distribution detection circuit (2) includes a multiplexer (4), a driver (5), and a sense amplifier (6), and the multiplexer (4) switches states between a first connection state in which first signal lines (HL1 to HLM) are connected to the driver (5) and second signal lines (VL1 to VLM) are connected to the sense amplifier (6), and a second connection state in which the first signal lines (HL1 to HLM) are connected to the sense amplifier (6) and the second signal lines (VL1 to VLM) are connected to the driver (5).

Claims

1. A method of specifying a touched position on a touch panel, including a plurality of first signal lines and a plurality of second signal lines which intersect with the plurality of first signal lines, by detecting a distribution of capacitance of a plurality of capacitors that are each formed on intersections of the plurality of first signal lines with the plurality of second signal lines,

the method comprising:

a first capacitance distribution detecting step of detecting a first capacitance distribution on the touch panel in accordance with electric charges corresponding to the plurality of capacitors which electric charges are outputted from the plurality of second signal lines by driving the plurality of first signal lines;

a first touched position specifying step of specifying a first touched position on the touch panel in accordance with the first capacitance distribution;

a second capacitance distribution detecting step of detecting a second capacitance distribution on the touch panel in accordance with electric charges corresponding to the plurality of capacitors which electric charges are outputted by the plurality of first signal lines by driving the plurality of second signal lines; and

a second touched position specifying step of specifying a second touched position on the touch panel in accordance with the second capacitance distribution.

2. The method as set forth in claim 1, wherein one of the first touched position, specified in the first touched position specifying step, and the second touched position, specified in the second touched position specifying step, is received as the touched position.

3. The method as set forth in claim 2, wherein:

a generation status of noise on the plurality of second signal lines is checked in accordance with the first capacitance distribution;

a generation status of noise on the plurality of first signal lines is checked in accordance with the second capacitance distribution;

in the first touched position specifying step, in a case where (i) the noise is generated on any of the plurality of second signal lines and (ii) the first touched position cannot be specified, the second touched position specified in the second touched position specifying step is received as the touched position; and

in the second touched position specifying step, in a case where (i) the noise is generated on any of the plurality of first signal lines and (ii) the second touched position cannot be specified, the first touched position specified in the first touched position specifying step is received as the touched position.

4. The method as set forth in claim 2, wherein:

a generation status of noise on the plurality of second signal lines is checked in accordance with the first capacitance distribution;

a generation status of noise on the plurality of first signal lines is checked in accordance with the second capacitance distribution;

in the first touched position specifying step, in a case where (i) the noise is generated between a first pair of circumscribing lines that circumscribe a hand placing region, which is a region in which a hand holding a pen is placed on the touch panel, along the plurality of second signal lines and (ii) the first touched position cannot be specified, the second touched position specified in the second touched position specifying step is received as the touched position; and

in the second touched position specifying step, in a case where (i) the noise is generated between a second pair of circumscribing lines that circumscribe the hand placing region along the plurality of first signal lines and (ii) the second touched position cannot be specified, the first touched position specified in the first touched position specifying step is received as the touched position.

5. The method as set forth in claim 1, wherein:

in the first touched position specifying step, a first touched position signal for specifying the first touched position is detected;

in the second touched position specifying step, a second touched position signal for specifying the second touched position is detected;

a position specified in accordance with a signal obtained by carrying out an AND operation with use of the first touched position signal and the second touched position signal is received as the touched position.

6. The method as set forth in claim 5, wherein:

first phantom noise is generated between a first pair of circumscribing lines that circumscribe a finger-touched region, which correspond to the touched position, along the plurality of first signal lines;

second phantom noise is generated between a second pair of circumscribing lines that circumscribe the finger-touched region along the plurality of second signal lines; and

the first phantom noise and the second phantom noise are cancelled in the signal obtained by carrying out the AND operation.

7. A touched position specifying circuit for specifying a touched position on a touch panel, including a plurality of first signal lines and a plurality of second signal lines which intersect with the plurality of first signal lines, by detecting a distribution of capacitance of a plurality of capacitors that are each formed on intersections of the plurality of first signal lines with the plurality of second signal lines,

the touched position specifying circuit comprising:

a multiplexer connected to the plurality of first signal lines and the plurality of second signal lines;

a driver connected to the multiplexer;

a sense amplifier connected to the multiplexer; and

a touched position specifying section connected to the sense amplifier, the touched position specifying section calculating the touched position by signal conversion,

the multiplexer switching a connection state between a first connection state and a second connection state,

the first connection state being a state in which the plurality of first signal lines are connected to the driver and the plurality of second signal lines are connected to the sense amplifier so that (i) drive signals are applied to the plurality of first signal lines via the driver, (ii) electric charges corresponding to the plurality of capacitors are outputted from the plurality of second signal lines, (iii) a first capacitance distribution on the touch panel is detected in accordance with the electric charges, and (iv) the touched position specifying section specifies a first touched position on the touch panel in accordance with the first capacitance distribution,

the second connection state being a state in which the plurality of first signal lines are connected to the sense amplifier and the plurality of second signal lines are connected to the driver so that (I) drive signals are applied to the plurality of second signal lines via the driver, (II) electric charges corresponding to the plurality of capacitors are outputted from the plurality of first signal lines, (III) a second capacitance distribution on the touch panel is detected in accordance with the electric charges, and (IV) the touched position specifying section specifies a second touched position on the touch panel in accordance with the second capacitance distribution.

8. The touched position specifying circuit as set forth in claim 7, wherein one of the first touched position, specified in the first connection state, and the second touched position, specified in the second connection state, is received as the touched position.

9. The touched position specifying circuit as set forth in claim 7, wherein:

in the first connection state, a first touched position signal for specifying the first touched position is detected from the plurality of second signal lines;

in the second connection state, a second touched position signal for specifying the second touched position is detected from the plurality of first signal lines;

a position specified in accordance with a signal obtained by carrying out an AND operation with use of the first touched position signal and the second touched position signal is received as the touched position.