POSITION DETECTING SENSOR, POSITION DETECTING DEVICE, AND POSITION DETECTING METHOD

• US 20130009653A1
• Filed: 05/09/2012
• Published: 01/10/2013
• Est. Priority Date: 07/08/2011
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Fukushima, Yasuyuki
• Granted Patent: US 9,000,780 B2
• Time in Patent Office: Days
• US Class Current: 324/679
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 27/26 Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• 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
• 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
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A position detecting sensor is configured by providing a dielectric member having flexibility between first conductors and second conductors and providing spacers for separating the first conductors or the second conductors from the dielectric member by a determined gap. When a pressing force is applied by an indicator (e.g., a finger or a pen) on the position detecting sensor, the first conductor and the second conductor come to abut each other, with the dielectric member interposed therebetween. Further, an abutting area (contact area) between the dielectric member and the conductor changes (e.g., increases) according to the pressing force applied by the indicator. Thus, capacitance of the capacitor formed between the first conductor and the second conductor is largely changed, to allow detection of a position indicated by the indicator as well as the pressing force applied at the indicated position with high sensitivity and high accuracy.

Claims

1. A position detecting sensor that utilizes a capacitive sensing system, the position detecting sensor including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a direction that intersects the first direction, the position detecting sensor being configured to detect a position indicated by an indicator by detecting a change in capacitance between the first conductor and the second conductor caused by a position indication operation of the indicator, wherein:

the plurality of first conductors have flexibility;

a dielectric member having flexibility is provided between the plurality of first conductors and the plurality of second conductors, a first surface of the dielectric member having flexibility abutting the plurality of first conductors or the plurality of second conductors;

one or more spacers are provided, to define a determined gap between, a second surface of the dielectric member that does not abut the plurality of second conductors or the plurality of first conductors, and the other of the plurality of first conductors or the plurality of second conductors, to which the dielectric member does not abut and which faces the second surface of the dielectric member; and

an abutting area between the second surface of the dielectric member having flexibility and the plurality of second conductors or the plurality of first conductors that face the second surface is changed when the plurality of first conductors are pressed in connection with a position indication operation of the indicator to thereby cause a change in the capacitance between the plurality of first conductors and the plurality of second conductors with the flexible dielectric member interposed therebetween.

2. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the first surface of the dielectric member having flexibility abuts the plurality of first conductors, and the second surface of the dielectric member having flexibility is separated from the plurality of second conductors by the determined gap defined by the one or more spacers.

3. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the first surface of the dielectric member having flexibility is separated from the plurality of first conductors by the determined gap defined by the one or more spacers, and the second surface of the dielectric member having flexibility abuts the plurality of second conductors.

4. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the dielectric member having flexibility is so disposed as to abut the plurality of first conductors, a second dielectric member is so disposed as to abut the plurality of second conductors, and an abutting area between the dielectric member having flexibility and the second dielectric member is changed when the plurality of first conductors are pressed in connection with a position indication operation of the indicator to thereby cause a change in the capacitance between the plurality of first conductors and the plurality of second conductors with both the dielectric member having flexibility and the second dielectric member interposed therebetween.

5. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, further comprising a first substrate having flexibility, on which the plurality of first conductors are disposed, and a second substrate, on which the plurality of second conductors are disposed.

6. The position detecting sensor that utilizes a capacitive sensing system according to claim 5, wherein a plurality of the spacers are disposed in areas between the plurality of first conductors disposed on the first substrate.

7. The position detection sensor that utilizes a capacitive sensing system according to claim 5, wherein a plurality of the spacers are disposed in areas between the plurality of second conductors disposed on the second substrate.

8. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein a plurality of the spacers each have a protruding shape and are dispersedly disposed on the second substrate.

9. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein a plurality of the spacers are provided by a sheet-like material having a surface defining a plurality of recesses and projections.

10. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the dielectric member has a film-like form.

11. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the dielectric member is fixed to the plurality of first conductors disposed in the first direction or to the plurality of second conductors disposed in the direction that intersects the first direction.

12. The position detecting sensor that utilizes a capacitive sensing system according to claim 11, wherein the dielectric member is fixed by coating or printing.

13. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the plurality of first conductors, the plurality of second conductors, and the dielectric member each have optical transparency.

14. The position detecting sensor that utilizes a capacitive sensing system according to claim 1, wherein the dielectric member is formed of a material selected from a group consisting of a glass material and a resin material.

15. A position detecting device including the position detecting sensor that utilizes a capacitive sensing system according to claim 1, the position detecting device further including an alternating current signal supply circuit configured to supply a determined alternating current signal to the plurality of first conductors or the plurality of second conductors, and a signal receiving circuit configured to receive a signal from the other of the plurality of first conductors or the plurality of second conductors, to which the alternating current signal is not supplied, to detect a change in the capacitance between the first conductor and the second conductor caused by a position indication operation of the indicator to thereby detect a position indicated by the indicator on the position detecting sensor.

16. A position and pressure detecting method for use with a position detecting sensor that utilizes a capacitive sensing system, the position detecting sensor including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a direction that intersects the first direction to thereby form a plurality of capacitors at cross-points where the plurality of first conductors intersect the plurality of second conductors, respectively, the position detecting sensor being configured to allow detection of a change in capacitance at each of the plurality of capacitors, and the position detecting sensor further including a flexible dielectric member interposed between the plurality of first conductors and the plurality of second conductors and one or more spacers disposed to define a determined gap between one surface of the dielectric member and the plurality of first conductors or the plurality of second conductors that said one surface of the dielectric member is facing, the position and pressure detecting method comprising:

detecting position(s) of one or more of the first conductors that are brought closer to the corresponding ones of the second conductors until they are separated from each other by a thickness of the dielectric member based on detection of a change in capacitance at each of the capacitors formed by said one or more of the first conductors and the corresponding ones of the second conductors caused by a decreasing distance between said one or more of the first conductors and the corresponding ones of the second conductors; and

detecting a pressing force applied either to said one or more of the first conductors or to the corresponding ones of the second conductors based on detection of a change in capacitance at each of the capacitors formed by said one or more of the first conductors and the corresponding ones of the second conductors caused by an increasing abutting area between said one surface of the flexible dielectric member and each of said one or more of the first conductors or the corresponding ones of the second conductors facing said one surface of the flexible dielectric member.

17. The position detecting method according to claim 16, further comprising detecting a pressing force applied either to said one or more of the first conductors or to the corresponding ones of the second conductors based on detection of a change in capacitance at each of the capacitors formed by said one or more of the first conductors and the corresponding ones of the second conductors caused by a decreasing distance between said one or more of the first conductors and the corresponding ones of the second conductors.

18. A position detecting sensor that utilizes a capacitive sensing system, the position detecting sensor comprising:

a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a direction that intersects the first direction to thereby form a plurality of capacitors at cross-points where the plurality of first conductors intersect the plurality of second conductors, respectively, either or both of the first conductors and the second conductors having flexibility;

a flexible dielectric member interposed between the plurality of first conductors and the plurality of second conductors; and

one or more spacers disposed to define a determined gap between one surface of the dielectric member and the plurality of first conductors or the plurality of second conductors that said one surface of the dielectric member is facing;

wherein the position detecting sensor is configured such that, when a pressing force is applied either to one or more of the first conductors or to the corresponding ones of the second conductors, (i) said one or more of the first conductors and the corresponding ones of the second conductors become closer to each other until they are separated from each other by a thickness of the dielectric member, to thereby change a capacitance of each of the capacitors formed by said one or more of the first conductors and the corresponding ones of the second conductors, and (ii) an abutting area increases between said one surface of the flexible dielectric member and each of said one or more of the first conductors or the corresponding ones of the second conductors facing said one surface of the flexible dielectric member, to thereby change the capacitance of each of the capacitors formed by said one or more of the first conductors and the corresponding ones of the second conductors.

19. The position detecting sensor according to claim 18, wherein the one or more spacers are integrally formed with said one surface of the flexible dielectric member.

20. The position detecting sensor according to claim 18, wherein a plurality of the spacers are disposed on both surfaces of the flexible dielectric member so as to define a first gap between one surface of the dielectric member and the plurality of first conductors and to define a second gap between another surface of the dielectric member and the plurality of second conductors.