JP2011002949A - Touch pad input device with antenna and electronic equipment loaded with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch pad input device with an antenna for suppressing the deterioration of position detecting precision while an antenna is arranged on an electrode for position detection of a touch pad, and electronic equipment loaded with the device.SOLUTION: The touch pad input device (10) with an antenna is provided with a sensing face exposed at an opening provided on a shield member (26). The sensing face is, for example, configured of a face sheet (22). The touch pad input device (10) with an antenna is provided with: an electrode group (34b, 36b, 38b) which is provided along the sensing face, and constitutes a plurality of measurement regions for measuring capacitance; and an antenna (40b) arranged between the electrode groups (34b, 36b, 38b) and the sensing face and for communicating with external equipment; and a magnetic member (39) arranged between the antenna (40b) and the electrode group (34b, 36b, 38b), and equipped with electric insulation property and magnetic permeability higher than that of the electrode group (34b, 36bk, 38b).

Description

  The present invention relates to a touchpad input device with an antenna, and an electronic apparatus equipped with the device.

  The touch pad input device is mounted on an electronic device such as a laptop personal computer (laptop computer). In a laptop computer, a main body having a keyboard and a display are connected by a hinge. In this main body, a touch pad input device is disposed on the front side of the keyboard.

In the laptop computer, a shield member is provided inside the housing of the main body. The shield member is provided so as to cover the electronic device inside the main body, and suppresses the emission or incidence of unwanted electromagnetic waves (EMI countermeasures).
However, the housing and the shield member of the main body are provided with an opening for arranging the touch pad input device, and the face sheet of the touch pad input device is exposed at the opening to form a sensing surface.

  As a touch pad input device, Patent Document 1 proposes a touch pad module with an antenna. In this touchpad module, it is considered that communication with the outside becomes possible through the antenna by arranging the antenna in the opening of the shield member.

  Specifically, in the touchpad module disclosed in Patent Document 1, for example, the antenna is provided on the printed circuit board of the touchpad. It is also contemplated that the antenna can be placed in a separate flexible layer between or adjacent to the layers used for the touchpad array itself.

JP-T-2002-539517 (paragraph numbers 0006, 0014, 0033 and FIG. 3 etc.)

  However, in the touchpad module disclosed in Patent Document 1, when the flexible layer for the antenna is directly disposed on the layer for the touchpad array itself, the antenna is generated around the antenna when transmitting. An eddy current is generated in the touch pad array due to the magnetic flux, and the position detection accuracy of the touch pad array is lowered.

  The present invention is made on the basis of the above-described circumstances, and an object of the present invention is to provide a touchpad input device with an antenna in which a decrease in position detection accuracy is suppressed while the antenna is disposed on a position detection electrode of the touchpad, And an electronic device equipped with the apparatus.

  In order to achieve the above object, the present invention employs the following solutions.

  First Solution: According to one aspect of the present invention, there is provided a touchpad input device with an antenna having a sensing surface that is exposed at an opening provided in a shield member that shields radiation noise in an electronic device. An electrode group provided along the sensing surface and constituting a plurality of measurement regions for measuring capacitance, and disposed between the electrode group and the sensing surface for communicating with an external device What is claimed is: 1. A touchpad input device with an antenna, comprising: an antenna; and a magnetic member disposed between the antenna and the electrode group, having an electrical insulation property and having a higher magnetic permeability than the electrode group. Provided.

  According to the touchpad input device with an antenna of the first solving means, the number of magnetic fluxes passing through the electrode group is reduced by guiding the magnetic flux generated by the antenna to the inside of the magnetic member. For this reason, the eddy current which generate | occur | produces in an electrode group is suppressed, and the fall of a position detection precision is suppressed.

Second Solution: Preferably, the thickness of the magnetic member between the electrode group and the sensing surface is 0.5 mm or less, and the real part of the relative permeability of the magnetic member is 10 or more.
According to the touch pad input device with an antenna of the second solving means, since the thickness of the magnetic member is 0.5 mm or less, the measurement of the capacitance is prevented by the magnetic member.
On the other hand, even if the thickness of the magnetic member is 0.5 mm or less, since the value of the real part of the magnetic permeability is 10 or more, the magnetic flux is guided to the inside of the magnetic member, and the number of magnetic fluxes passing through the electrode group is It is definitely reduced.

Third Solution: Preferably, the antenna is formed in close contact with the antenna substrate disposed between the electrode group and the sensing surface.
According to the touchpad input device with an antenna of the third solving means, since the antenna is formed in close contact with the antenna substrate, the antenna is reliably supported, and deformation of the antenna is prevented.

Fourth solving means: Preferably, the antenna comprises a conducting wire having a circular or elliptical cross-sectional shape.
According to the touchpad input device with an antenna of the fourth solving means, since the cross-sectional shape of the antenna is a circle or an ellipse, when an object such as a fingertip is positioned on the antenna, the gap between the object and the antenna The gap formed is increased, and an object is sensed through this gap. For this reason, according to this touchpad input device with an antenna, the reduction of the sensing area due to the provision of the antenna is further suppressed.

Fifth Solution: Preferably, the antenna is formed of a conductor that spirally extends a plurality of turns along the outer edge of the sensing surface, the outer end of the antenna is grounded, and the inner end of the antenna is It is connected to a high-frequency circuit through a capacitor.
According to the touchpad input device with an antenna of the fifth solving means, as described below, reduction of the area (effective area) of the region where the contact of the object on the sensing surface can be detected is suppressed.

In the magnetic field coupling type loop antenna, one end is grounded, but the electric resistance per unit length in the loop antenna is large, so that the potentials are different at both ends.
Here, in the capacitance type touch pad input device, a change in capacitance caused by forming a virtual capacitor between the electrode group and an object in contact with the sensing surface is measured. In this case, theoretically, even if an electrode with a floating electric potential enters between the electrode group and the sensing surface, it does not interfere with the measurement of the change in capacitance, whereas when an installed electrode enters, This hinders the measurement of capacitance changes.

  If this theory is applied to a loop antenna, the grounded one side of the loop antenna hinders measuring the change in capacitance. On the other hand, since the potential on the other side of the loop antenna is connected to the high-frequency circuit via a capacitor, it is floating with respect to the ground potential due to the electrical resistance of the loop antenna itself. For this reason, the other side of the loop antenna does not interfere with measuring the change in capacitance as compared to the grounded side.

  Therefore, when the number of turns of the loop antenna is two or more, if the outer end of the loop antenna disposed outside the sensing surface is grounded, the portion of the loop antenna disposed inside the sensing surface is Does not interfere with measuring changes in capacitance. As a result, reduction of the effective area of the sensing surface due to the presence of the loop antenna is suppressed.

  Sixth solving means: Preferably, the apparatus includes a position detection circuit that detects a position of an object that contacts the sensing surface based on a capacitance measured in each of the measurement regions, and the position detection circuit includes the antenna. A threshold value set in consideration of the variation in the capacitance on the sensing surface based on the presence of the threshold, or a storage unit for storing an arithmetic expression necessary for setting the threshold value, and the electrostatic capacitance measured in each of the measurement regions A comparison / determination unit that compares a capacitance with the threshold and detects a position of an object in contact with the sensing surface based on a result of the comparison;

  According to the touchpad input device with an antenna of the sixth solving means, since the threshold is set in consideration of the variation in the capacitance based on the presence of the antenna, the change in the capacitance regardless of the presence of the antenna. Is measured with high accuracy. As a result, according to the touchpad input device with an antenna, the position of the object that contacts the sensing surface is detected with high accuracy.

Seventh Solution: Preferably, the threshold value is set based on an initial value of capacitance actually measured when no object is in contact with the sensing surface for each touchpad input device with an antenna. .
According to the touchpad input device with an antenna of the seventh solving means, the threshold value is set based on the initial value of the actually measured capacitance, so that the relative position of the antenna with respect to the electrode group is based on the assembly accuracy. Even if it fluctuates, the change in capacitance is measured with high accuracy.

Eighth Solution: As another aspect of the present invention, there is provided an electronic apparatus comprising the antenna-equipped touchpad input device according to any one of the solutions 1 to 8.
The electronic device of the eighth solving means operates smoothly as intended by the person who operates the electronic device because the position detection accuracy of the antenna-equipped touch pad input device is suppressed from decreasing.

According to the touchpad input device with an antenna of the present invention, even if the antenna is provided between the sensing surface and the electrode group, the magnetic member is disposed between the antenna and the electrode group, thereby making contact with the sensing surface. The position of the object to be detected is detected with high accuracy.
The electronic device of the present invention operates smoothly as intended by the operator because the decrease in position detection accuracy of the touchpad input device with an antenna is suppressed.

It is a perspective view which shows the external appearance of the personal computer carrying the touchpad input device of 1st Embodiment. It is a schematic fragmentary sectional view which follows the II-II line | wire of FIG. 1 is a perspective view showing a schematic appearance of a touch pad input device according to a first embodiment. FIG. 4 is an exploded perspective view of the touch pad input device of FIG. 3. It is a top view of the antenna layer in FIG. FIG. 6 is a schematic partial sectional view taken along line VI-VI in FIG. 5. FIG. 2 is a block diagram schematically showing an electric circuit in the personal computer of FIG. 1. It is a figure for demonstrating the schematic structure of the CV conversion part in FIG. It is a graph which shows the relationship between the presence or absence of an antenna, and an output voltage. It is a top view of the antenna layer concerning 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a laptop personal computer (electronic device) 11 equipped with a touchpad input device 10 with an antenna according to the first embodiment. The computer 11 has a main body 12 and a display 14, and the main body 12 and the display 14 are coupled via a hinge. The display 14 reversibly stands (opens) with respect to the main body 12 by being rotated about the hinge as a fulcrum from a state of being superimposed on the main body 12 that is normally placed flat (closed state).

  The display 14 has a display housing 16 made of, for example, resin. The display housing 16 has a flat box shape and has a size substantially equal to, for example, A4 paper. Although the display housing 16 has a surface (inner surface) that faces the main body 12 when in the closed state, an opening is formed on the inner surface of the display housing 16 over substantially the entire area. For example, a liquid crystal panel 18 is exposed in the opening 16 a of the display housing 16.

The main body 12 has a flat box-shaped resin main housing 20.
An opening 20a is provided on the upper surface of the main housing 20 facing the display 14 in the closed state when viewed from the liquid crystal panel 18, that is, on the hinge side, and the keyboard 21 is disposed in the opening 20a. Has been. The size of the upper surface of the main housing 20 is substantially the same as the inner surface of the display housing 16.

An opening 20 b is also formed on the upper surface of the main housing 20 at the center in front of the keyboard 21. The face sheet 22 of the touchpad input device with an antenna is exposed in the opening 20b.
Further, an opening 20c is formed on the upper surface of the main housing 20 in front of the opening 20b, and two buttons 24a and 24b are exposed side by side in the width direction of the main housing 20 in the opening 20c.
In addition, the area | region of the both sides of opening 20b, 20c in the upper surface of the main housing 20 functions as a palm rest.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and shows a partial cross section of the main body 12.
A metal shield member 26 is provided inside the main housing 20. The shield member 26 has a slightly smaller shape than the main housing 20, and substantially the entire area is covered by the main housing 20 except for the area where the keyboard 21, the face sheet 22, and the buttons 24 a and 24 b are exposed.

An opening 26 a is formed on the upper wall of the shield member 26 corresponding to the position of the opening 20 b of the main housing 20. A bottom plate 27 slightly larger than the opening 26a is disposed inside the shield member 26 so as to correspond to the opening 26a. The bottom plate 27 has conductivity, and the bottom plate 27a and the upper wall of the shield member 26 are mechanically and electrically connected by, for example, a plurality of conductive connection members 27b.
The bottom plate 27 a is disposed so as to close the opening 26 a of the shield member 26, but the bottom plate 27 a is separated from the upper wall of the shield member 26. For this reason, the bottom plate 27a and the connection member 27b form a recess 27 continuous with the opening 26a, and the touchpad input device 10 with an antenna is disposed in the recess 27.

[Touchpad input device with antenna]
The touchpad input device with an antenna 10 includes a printed circuit board 28 having wiring (not shown) having an appropriate pattern, and the printed circuit board 28 is fixed in the recess 27 by a support member (not shown).

The printed circuit board 28 is disposed substantially parallel to the upper surface of the main housing 20. Electrical elements such as LSI chips 30a and 30b are mounted on the bottom surface of the recess 27, that is, the bottom surface of the printed circuit board 28 facing the bottom plate 27a.
A laminated body 32 including the face sheet 22 is fixed to the upper surface of the printed circuit board located on the opening 20b side.

  FIG. 3 is a perspective view showing a schematic appearance of the touchpad input device 10 with an antenna. The printed circuit board 28 has a rectangular shape equivalent to the laminated body 32, and the laminated body 32 is fixed to one surface of the printed circuit board 28. The stacked body 32 is connected to an electrical element mounted on the other surface of the printed circuit board 28.

  The electrical element mounted on the printed circuit board 28 is connected to a mother board (not shown) disposed inside the shield member 26 through an input terminal.

[Laminate]
FIG. 4 is a schematic perspective view showing the touch pad input device 10 with the antenna in an exploded manner.
The stacked body 32 includes a ground electrode layer 34, a Y drive electrode layer 36, an X drive electrode layer 38, a magnetic layer 39, an antenna layer 40, and the face sheet 22 in this order from the printed circuit board 28 side. The ground electrode layer 34, the Y drive electrode layer 36, the X drive electrode layer 38, the magnetic layer 39, the antenna layer 40, and the face sheet 22 are in close contact with each other by an adhesive or the like.

  The ground electrode layer 34 includes a substantially square film substrate (ground substrate) 34a and a planar ground electrode 34b formed integrally with the film substrate 34a. Although the ground electrode 34b extends uniformly over substantially the entire area of one surface of the film substrate 34a, a plurality of perforated slits are formed in the ground electrode 34b.

The Y drive electrode layer 36 is formed integrally with the substantially square film substrate (Y drive electrode substrate) 36a, the lattice-shaped Y drive electrode 36b formed integrally with the film substrate 36a, and the film substrate 36a. It comprises a comb-shaped detection electrode 36c. The Y drive electrode 36b and the detection electrode 36c are distributed over substantially the entire area of one surface of the film substrate 36a while being arranged so as to mesh with each other.
Specifically, the Y drive electrode 36 b is configured by a plurality of conductive bands parallel to each other, and the conductive bands extend in the depth direction of the main body 12 of the personal computer 11. They are separated from each other at regular intervals in the width direction.

  The detection electrode 36c includes a plurality of conductive bands parallel to each other and one conductive band that connects one end of these bands to each other. Similarly to the plurality of conductive bands of the Y drive electrode 36b, the plurality of conductive bands of the detection electrode 36c also extend in the depth direction of the main body 12 of the personal computer 11, and extend in the width direction of the main body 12 of the personal computer 11. Are spaced apart from each other at regular intervals. The plurality of conductive bands of the detection electrode 36c are arranged between the plurality of conductive bands of the Y drive electrode 36b.

  The X drive electrode layer 38 includes a substantially rectangular film substrate (X drive electrode substrate) 38a and a lattice-shaped X drive electrode 38b formed integrally with the film substrate 38a. The X drive electrodes 38b are distributed over substantially the entire area of one surface of the film substrate 38a. Specifically, the X drive electrode 38 b is configured by a plurality of conductive bands parallel to each other, and the conductive bands extend in the width direction of the main body 12 of the personal computer 11, respectively. They are separated from each other at regular intervals in the depth direction.

  Therefore, the Y drive electrode 36b and the X drive electrode 38b are orthogonal to each other in a grid pattern when viewed in the stacking direction. The detection electrode 36c, the Y drive electrode 36b, and the X drive electrode 38b constitute an electrode group for detecting the position of an object such as a fingertip that contacts the surface of the face sheet 22.

[Antenna layer]
The antenna layer 40 includes a substantially rectangular film substrate (antenna substrate) 40a and an antenna 40b formed integrally with the film substrate 40a.

FIG. 5 is a plan view showing the antenna layer 40, and the antenna 40b is composed of a conductor band extending in a predetermined pattern. The width of the conductor is, for example, in the range of 0.1 mm to 1.00 mm. The antenna 40b is preferably a loop antenna extending in a spiral shape along the outer edge of the film substrate 40a, and the number of turns of the loop antenna is preferably two or more.
In addition, although metals, such as aluminum and copper, can be used as a conductor, you may use electroconductive oxides, such as ITO (indium tin oxide).

  6 is a partial cross-sectional view taken along line VI-VI in FIG. The cross section of the band constituting the antenna 40b is, for example, a quadrangle. Such an antenna 40b can be formed using a printing technique.

[Magnetic layer]
FIG. 6 shows the face sheet 22 and the magnetic layer (magnetic member) 39 together with the antenna layer 40 by a one-dot chain line. The magnetic layer 39 has, for example, a rectangular thin plate shape.
The real part μ ′ of the relative permeability (complex relative permeability) of the magnetic layer 39 is higher than that of the conductor of the electrode group, and is preferably 10 or more. Further, the thickness t of the magnetic layer 39 is preferably 0.5 mm or less. Furthermore, the magnetic layer 39 has electrical insulation. The relative dielectric constant ε of the magnetic layer 39 is, for example, 9.

As such a magnetic layer 39, a soft magnetic powder such as Sendust or Permalloy hardened by a binder can be used.
The film substrates 34a, 36a, 38a, 40a, the magnetic layer 39, and the face sheet 22 have substantially the same size and are overlapped with each other with four corners aligned.

[Circuit configuration]
FIG. 7 is a block diagram showing a schematic electric circuit of the personal computer 11 including the touch pad input device 10 with an antenna.
A CPU (Central Processing Unit) 50 and a memory 52 are mounted on the mother board of the personal computer 11. The CPU 50 is connected to a hard disk 56 disposed inside the shield member 26 via a disk controller 54 that is also mounted on the mother board.

  When the personal computer 11 is turned on, the CPU 50 starts up a BIOS (Basic Input Output System) and an operating system stored in the hard disk 56, and then executes application software in accordance with an instruction from the operator.

  The CPU 50 is connected to the liquid crystal panel 18 via a display controller 58 mounted on the mother board, and the liquid crystal panel 18 displays an input / output screen of the BIOS, operating system, and application software.

  Further, the CPU 50 is connected to the keyboard 21 via the keyboard controller 60 mounted on the mother board, and performs a predetermined operation on the operating system or application software in response to pressing of each button of the keyboard 21 by the operator. Execute.

In addition, the CPU 50 is connected to the antenna-attached touch pad input device 10 via the touch pad controller 62 mounted on the mother board.
Specifically, the touchpad input device with an antenna 10 includes a position detection circuit 64 connected to the X drive electrode 38b, the Y drive electrode 36b, the detection electrode 36c, and the ground electrode 34b. The position detection circuit 64 detects a change in capacitance between the X drive electrode 38b and the Y drive electrode 36b and the detection electrode 36c while scanning the voltage applied to the X drive electrode 38b and the Y drive electrode 36b. Then, the position detection circuit 64 detects the contact position of the fingertip or the like on the face sheet 22 based on the change in capacitance.

Scanning the voltage means sequentially applying the voltage to the plurality of conductor bands of the X drive electrode 38b and the Y drive electrode 36b.
Accordingly, when viewed instantaneously, of the conductor bands of the X drive electrode 38b and the Y drive electrode 36b, one conductor band to which a voltage is applied and the detection electrode 36c cooperate to constitute one measurement region. To do.

In a longer time range, a plurality of measurement regions are distributed along the face sheet 22 by sequentially applying voltages to all conductor bands of the X drive electrode 38b, the Y drive electrode 36b, and the detection electrode 36c. It will be allowed.
Note that the measurement region also includes a region of the sensing surface located on the conductor band of the X drive electrode 38b, the Y drive electrode 36b, and the detection electrode 36c.
A signal related to the contact position detected by the position detection circuit 64 is input to the touchpad controller 62 via the interface 66.

In the present embodiment, the entire surface of the face sheet 22 is exposed at the opening 20b, and the position detection circuit 64 can detect the contact position of an object such as a fingertip on the entire surface of the face sheet 22. For this reason, in this specification, the whole surface of the face sheet 22 is also referred to as a sensing surface.
Although the position detection circuit 64 and the interface 66 are configured by electric elements such as an LSI chip 30a mounted on a printed circuit board, in FIG. 4, an X drive electrode 38b, a Y drive electrode 36b, a detection electrode 36c, and Wiring for connecting the ground electrode 34b and the position detection circuit 64 is omitted.

  The CPU 50 changes the position of the cursor displayed on the liquid crystal panel 18 by the operating system in accordance with the change in the contact position of the fingertip on the face sheet 22.

  The buttons 24a and 24b are also connected to the CPU 50 via the interface 66 and the touch pad controller 62. For example, if the position of the fingertip is changed on the face sheet 22 while one of the buttons 24a is pressed, a predetermined value on the liquid crystal panel 18 is displayed. The display area is selected and highlighted. If the button 24a is pressed twice in succession, the command selected according to the cursor position is executed. Further, by pressing the other button 24b, for example, a menu screen is displayed.

On the other hand, referring also to FIG. 5, the outer end of the antenna 40 b is grounded, and the inner end of the antenna 40 b is connected to the matching circuit 70 via a capacitor 69. The capacitor 69 and the matching circuit 70 are configured by an electrical element such as an LSI chip 30b that is mounted on the printed circuit board 28 and different from the electrical element for the position detection circuit 64.
In FIG. 4, wiring for connecting the antenna 40b and the capacitor 69 is omitted.

The matching circuit 70 is connected to the CPU 50 via a transmission / reception circuit 72 and a wireless controller 74 mounted on the mother board. For example, the CPU 50 operates the wireless controller 74, the transmission / reception circuit 72, the matching circuit 70, and the antenna 40b by resident application software, and performs communication with the outside continuously or intermittently.
The transmission / reception circuit 72 may be mounted on the printed circuit board 28 of the touch pad input device 10 with an antenna instead of the mother board.

  In the present embodiment, the antenna 40b is a magnetic field type loop antenna for RFID (Radio Frequency Identification). When the operator holds the RFID tag (non-contact IC card) over the face sheet 22, communication in the 13.56 MHz frequency band (short wave: HF band), for example, is performed between the RFID tag and the antenna 40b.

  For example, the antenna 40b is used for ID authentication for confirming whether or not the personal computer 11 has a proper use authority. In this case, as soon as the personal computer 11 is turned on, power is supplied to the wireless controller 74, the transmission / reception circuit 72, the matching circuit 70, and the antenna 40b so that communication for ID authentication is performed. Is preferred.

  Here, the position detection circuit 64 for detecting the position of the object based on the change in capacitance includes a CV conversion unit 64a, a storage unit 64b, and a comparison determination unit 64c.

[CV conversion unit]
The CV conversion unit 64a detects a change in capacitance in each measurement region as a change in voltage.
FIG. 8 is an electric circuit diagram schematically showing the CV conversion unit 64a. In FIG. 8, Vin is a voltage (drive voltage) applied to the X drive electrode 38b or the Y drive electrode 36a. Ci is a capacitance between the X drive electrode 38b or the Y drive electrode 36b and the detection electrode 34c, that is, a capacitance (initial value) when no object is in contact with the sensing surface.

  Ca is the capacitance between the X drive electrode 38b or Y drive electrode 36b and the object when an object such as a fingertip contacts the sensing surface, and Cb is the same when the object contacts the sensing surface. , The capacitance between the detection electrode 34c and the object. Cx is the capacitance of the object when the object contacts the sensing surface.

Therefore, a combination of Ci, Ca, Cb, and Cx is a capacitance (combined capacitance) Ct in each measurement region.
The CV conversion unit 64a includes an amplifier 80, a measurement capacitor 82, and a reset switch 84, and a voltage (output voltage) Vout output from the CV conversion unit 64a changes according to the combined capacitance Ct. .

[Storage unit and comparison determination unit]
The storage unit 64b stores a threshold value, and the comparison / determination unit 64c compares the threshold value with the output voltage Vout, and an object such as a fingertip contacts the sensing surface, that is, each measurement region, based on the comparison result. It is determined whether or not.
Here, in the present embodiment, as a preferable aspect, the threshold value stored in the storage unit 64b is set in consideration of variations in capacitance based on the presence of the antenna 40b.

  Specifically, as shown in FIG. 9, the antenna 40 b exists in the measurement region where the antenna 40 b exists between the conductor band of the X drive electrode 38 b or the Y drive electrode 36 b and the face sheet 22. The initial value of the electrostatic capacitance is lower than that of the measurement region that is not, and the combined capacitance when the fingertip or the like touches is also reduced.

  Therefore, the storage unit 64b stores at least two threshold values. The first threshold value is a threshold value for a measurement region in which the antenna 40b exists between the conductor band of the X drive electrode 38b or the Y drive electrode 36b and the face sheet 22. The second threshold is a threshold for a measurement region in which the antenna 40b does not exist between the conductor band of the X drive electrode 38b or the Y drive electrode 36b and the face sheet 22. The first threshold value is larger than the second threshold value.

  Preferably, the threshold value is actually measured for each of the assembled touchpad input devices 10 with an antenna, and the initial value of the capacitance is actually measured, and the threshold value is set and stored based on the measured initial value.

  According to the touchpad input device with an antenna 10 of the first embodiment described above, the number of magnetic fluxes passing through the electrode group is reduced by guiding the magnetic flux generated by the antenna to the inside of the magnetic member. For this reason, the eddy current which generate | occur | produces in an electrode group is suppressed, and the fall of a position detection precision is suppressed.

And according to the touchpad input device 10 with an antenna of 1st Embodiment, since the thickness of a magnetic member is 0.5 mm or less, it is prevented that the measurement of an electrostatic capacitance is prevented by a magnetic member.
On the other hand, even if the thickness of the magnetic member is 0.5 mm or less, since the value of the real part of the magnetic permeability is 10 or more, the magnetic flux is guided to the inside of the magnetic member, and the number of magnetic fluxes passing through the electrode group is It is definitely reduced.

  Further, according to the touchpad input device with an antenna 10 of the first embodiment, since the antenna is formed in close contact with the antenna substrate, the antenna is reliably supported and the antenna is prevented from being deformed.

Further, according to the touchpad input device with an antenna 10 of the first embodiment, as described below, the reduction of the area (effective area) of the region where the contact of the object on the sensing surface can be detected is suppressed.
The antenna 40b is a magnetically coupled loop antenna, and one end of the antenna 40b is grounded. However, since the electric resistance per unit length of the loop antenna is large, the potentials are different at both ends.

  Here, in the capacitance type touch pad input device, a change in capacitance caused by forming a virtual capacitor between the electrode group and an object in contact with the sensing surface is measured. In this case, theoretically, even if an electrode with a floating electric potential enters between the electrode group and the sensing surface, it does not interfere with the measurement of the change in capacitance, whereas when an installed electrode enters, This hinders the measurement of capacitance changes.

  If this theory is applied to the antenna 40b, the grounded outer end side (outer winding portion) of the antenna 40b becomes an obstacle to measuring the change in capacitance. On the other hand, the potential on the inner end side (inner winding portion) of the antenna 40b is connected to a high frequency circuit such as the matching circuit 70 and the transmission / reception circuit 72 via the capacitor 69, and therefore, the electric resistance of the outer winding portion Floating with respect to ground potential. For this reason, the inner winding portion of the antenna 40b does not hinder measurement of a change in capacitance as compared with the grounded outer winding portion.

Therefore, when the number of turns of the loop antenna is two or more, if the outer end of the antenna 40b arranged outside the sensing surface is grounded as in the present embodiment, the loop antenna is arranged inside the sensing surface. The portion of the antenna 40b that does not interfere with measuring the change in capacitance. As a result, reduction of the effective area of the sensing surface due to the presence of the antenna 40b is suppressed.
Note that the area of the sensing surface directly above the outer winding portion of the antenna 40b may not be used in advance as a dead area.

  Furthermore, according to the touchpad input device with an antenna 10 of the first embodiment, the threshold value is set in consideration of the variation in capacitance based on the presence of the antenna 40b. The change in capacitance is measured with high accuracy. As a result, according to this touch pad input device 10 with an antenna, the position of the object that contacts the sensing surface is detected with high accuracy.

  In addition, according to the touchpad input device with an antenna 10 of the first embodiment, since the threshold is set based on the actually measured initial value of the capacitance, the relative position of the antenna 40b with respect to the electrode group is determined. Even if there is variation based on the assembly accuracy, the position of the object in contact with the sensing surface is detected with high accuracy.

  And since the fall of the position detection precision of the touchpad input device 10 with an antenna is suppressed, the personal computer 11 of 1st Embodiment operate | moves smoothly as the person who operates an electronic device aims.

[Second Embodiment]
FIG. 10 shows an antenna layer 90 used in the touchpad input device with an antenna 10 of the second embodiment. In the antenna layer 90, a separate antenna 90b is fixed to the film substrate 40a using, for example, an adhesive. The antenna 90b is formed by winding a conducting wire having a circular cross section, and is a loop antenna having two turns as in the case of the first embodiment.
The antenna 90b may be formed by winding a conductive wire having an elliptical cross section, or may be fixed by another method by omitting the film substrate 40a.

  According to the second embodiment, since the cross-sectional shape of the antenna 90b is circular or elliptical, when an object such as a fingertip is positioned on the antenna 90b, there is a gap formed between the object and the antenna 90b. The object becomes sensed through this gap. For this reason, according to this touchpad input device 10 with an antenna, the reduction of the sensing area by providing the antenna 90b is further suppressed.

The present invention is not limited to the first embodiment and the second embodiment described above, and various modifications can be made.
For example, the ground electrode 34b, the detection electrode 36c, the Y drive electrode 36b, and the X drive electrode 38b are formed on separate film substrates 34a, 36a, 38a, but these are formed on the front and back of one or two film substrates. May be. Alternatively, the ground electrode 34b, the detection electrode 36c, the Y drive electrode 36b, and the X drive electrode 38b may be integrally formed on the multilayer printed circuit board using a multilayer printed circuit board.

That is, the ground electrode layer 34, the Y drive electrode layer 36, and the X drive electrode layer 38 only need to include at least the ground electrode 34b, the detection electrode 36c, the Y drive electrode 36b, and the X drive electrode 38b. The configuration of the substrate that supports the detection electrode 36c, the Y drive electrode 36b, and the X drive electrode 38b is not particularly limited.
Furthermore, the detection electrode 36c is omitted, and when the voltage is applied to the X drive electrode 38b, the Y drive electrode 36b is used as the detection electrode, and conversely, when the voltage is applied to the Y drive electrode 36b, the X drive electrode 38b may be used as a detection electrode.

Furthermore, although the contact position of the fingertip or the like is detected by orthogonal coordinates, the electrode group may be configured to be detected by polar coordinates.
Furthermore, the number of turns of the antenna 40b is not limited to two.

  On the other hand, in the first and second embodiments, the sensing surface is formed by the face sheet 22, but the sensing surface may be formed by the antenna layer 40 or the like without the face sheet 22.

  In addition, the threshold value is set and stored based on, for example, an average value of the measured initial value, by actually measuring the initial value of the capacitance only for an arbitrary number of touchpad input devices 10 with an antenna. Also good. That is, a threshold set based on a representative initial value may be used in common for all touch pad input devices 10 with an antenna.

  Alternatively, the threshold value may be set, for example, by measuring the initial value of the capacitance in each measurement region each time the antenna-attached touchpad input device 10 is activated. In this case, instead of the threshold value, an arithmetic expression necessary for calculating the threshold value from the initial value may be stored in the storage unit 64b.

Further, although the magnetic layer 39 has a quadrangular shape, the magnetic layer 39 only needs to exist at least directly below the antenna 40b. For example, the magnetic layer 39 may have a square shape along the antenna 40b.
Finally, the touchpad input device with an antenna of the present invention has been described as an example embodied in a laptop personal computer, but it can also be applied to mobile electronic devices such as PDAs and mobile phones. Of course.

10 Touchpad input device with antenna 11 Personal computer (electronic equipment)
12 Main body 14 Display 18 Liquid crystal panel 20 Main housing 20b Opening 21 Keyboard 22 Face sheet (sensing surface)
26 Shield member 26a Opening 27 Recess 27a Bottom plate 27b Connection member 28 Printed circuit board 34b Ground electrode 36b Y drive electrode (electrode group)
36c Detection electrode (electrode group)
38b X drive electrode (electrode group)
39 Magnetic layer (magnetic member)
40b antenna

Claims (8)

A touchpad input device with an antenna having a sensing surface exposed at an opening provided in a shield member that shields radiation noise in an electronic device,
A group of electrodes provided along the sensing surface and constituting a plurality of measurement regions for measuring capacitance;
An antenna disposed between the electrode group and the sensing surface for communicating with an external device;
A touchpad input device with an antenna, comprising: a magnetic member that is disposed between the antenna and the electrode group and has electrical insulation and a higher magnetic permeability than the electrode group. In the touchpad input device with an antenna according to claim 1,
The touchpad input with an antenna is characterized in that the thickness of the magnetic member between the electrode group and the sensing surface is 0.5 mm or less, and the real part of the relative permeability of the magnetic member is 10 or more. apparatus. In the touchpad input device with an antenna according to claim 1 or 2,
The antenna touchpad input device, wherein the antenna is formed in close contact with an antenna substrate disposed between the electrode group and the sensing surface. In the touchpad input device with an antenna according to claim 1 or 2,
The antenna-attached touchpad input device, wherein the antenna is made of a conducting wire having a circular or elliptical cross-sectional shape. In the touchpad input device with an antenna as described in any one of Claims 1 thru | or 4,
The antenna is made of a conductor that spirally extends at a plurality of turns along the outer edge of the sensing surface,
The outer end of the antenna is grounded,
An antenna-equipped touch pad input device, wherein an inner end of the antenna is connected to a high-frequency circuit through a capacitor. In the touchpad input device with an antenna as described in any one of Claims 1 thru | or 5,
A position detection circuit that detects a position of an object that contacts the sensing surface based on a capacitance measured in each of the measurement regions;
The position detection circuit includes:
A storage unit that stores a threshold value set in consideration of variations in the capacitance on the sensing surface based on the presence of the antenna or an arithmetic expression necessary for setting the threshold value;
A comparison determination unit configured to compare the capacitance measured in each of the measurement regions with the threshold and detect a position of an object in contact with the sensing surface based on a result of the comparison; Touchpad input device with antenna. The touchpad input device with an antenna according to claim 6,
The threshold value is set based on an initial value of capacitance actually measured when no object is in contact with the sensing surface for each touch pad input device with an antenna. Input device.   An electronic apparatus comprising the antenna-attached touchpad input device according to claim 1.

Images