JP6772658B2 - Capacitive input device - Google Patents

Description

The present invention relates to a capacitance type input device, and more particularly to an input device having a touch switch function by a finger and a coordinate detection function by an input pen.

A touch switch has been conventionally known as an input device using a capacitance coupling method. The capacitance coupling type touch switch is composed of a panel switch and a control board. The panel switch is made of acrylic, which is an electrode film on which silver paste or ITO (indium tin oxide) is printed as a switch electrode on the surface of a normal film (generally polyethylene terephthalate film: PET film is used). It is composed of an insulating base material such as glass or resin bonded with an adhesive (double-sided tape, etc.). When a finger or hand approaches the switch electrode, a parallel plate capacitor is formed between the switch electrode and the finger or hand, and capacitance is generated. This change in capacitance is converted into frequency by a C / F conversion circuit (a circuit that converts capacitance C to frequency F) formed by a capacitor C and a resistor R, and that frequency is converted into an input capture function (number of frequencies). It is replaced with digital data by the function of counting), and the on / off state of the touch switch is judged by arithmetic processing. When there are a plurality of switch electrodes, the switch electrodes are selected by a switching circuit provided for each switch electrode (see Japanese Patent Application Laid-Open No. 2005-084982).

However, the method of converting the change in capacitance into frequency by the C / F conversion circuit is operated by using frequency, so that the influence of frequency mixing, which is noise generated in the living environment, is avoided. The current situation is that it cannot be done.

Further, in the above-mentioned method of converting the change in capacitance into a frequency using a C / F conversion circuit, a number (M ×) consisting of a plurality of switches, for example, y (horizontal) M rows and x (vertical) N columns. When N) arranging switch electrodes, the number of wiring patterns for connecting each switch electrode to the control board is the same as the number (M × N) described above, and the wiring space other than the switch electrodes of the panel switch is used. Was required, and miniaturization was difficult.

In order to solve the problem of the above-mentioned method of converting the change in capacitance into a frequency using a C / F conversion circuit, a plurality of switches arranged in parallel and at equal intervals made of a conductive material on the back surface of the insulator. A plurality of switch electrodes are provided on the front surface of the insulator and parallel to each other at equal intervals so as to intersect the plurality of switch electrodes provided on the back surface at right angles, and a plurality of switch electrodes provided on the back surface of the insulator. In order to measure the change in capacitance between the insulator and the plurality of switch electrodes provided on the surface of the insulator, a sin signal is applied to the plurality of switch electrodes provided on the back surface of the insulator to apply a sin signal to the surface of the insulator. A multiplication circuit for multiplying the current / voltage-converted voltage by the sin signal and the cos signal is provided by a current / voltage conversion circuit connected to a plurality of switch electrodes provided, and the multiplication circuit and the low-pass filter are used to obtain the multiplication circuit. A capacitance coupling type input method has also been proposed in which a sin signal and a cos signal are converted into a DC signal and the on / off state of the switch is determined by measuring the voltage. (See JP-A-2014-164535).

When arranging the number (M × N) of switch electrodes consisting of y (horizontal) M rows and x (vertical) N columns on the panel, the number of wiring patterns connected to the control board is the horizontal M rows. Since only the number of vertical N columns added (M + N) is required, a touch switch with M horizontal rows and N vertical columns of switch electrodes has a capacitance that is resistant to noise even in devices that require miniaturization. It can be used as a coupling type input device.

Japanese Unexamined Patent Publication No. 2005-08492 Japanese Unexamined Patent Publication No. 2014-164535

In the capacitance coupling type input device, it is premised that the input is performed by the finger. In the input by the finger, when selecting a switch smaller than the size of the finger, the selection item is hidden by the finger and it is difficult to select. It is also possible that you accidentally press a switch for a different item without being able to see it. Therefore, the size of the switch is limited to the size of a finger for comfortable operation, and the touch part at the tip is a conductive pen that inputs with a flexible conductor that contains carbon in silicon rubber as an input pen. There is also a method of using, but it is a capacitance coupling method with the same principle as a finger, the switch cannot be made small, and since it is not possible to distinguish between a conductive pen and a finger, the hand touches the panel switch when using the conductive pen. Then, it malfunctions.

In addition, there is a pen tablet that operates with a dedicated input pen when selecting a switch smaller than the size of a finger, and there is a coordinate detection function that allows drawing input because the pen touch position can be operated more finely, but it is operated once with the input pen The operation is more troublesome than directly inputting with a finger.

The present invention has a transmission / reception switching circuit connected to electrodes arranged in a grid of x and y with an insulator in between, and a selection circuit for selecting an input pen and an x electrode. In order to measure the current linked to the change in capacitance between the x and y electrodes, and to measure the capacitance-coupled current between the x and y electrodes and the pen tip conductor with the input pen, the transmission is performed. A sin signal is applied to the connected electrodes from the synchronous transmission circuit, while the current measured by the electrode or input pen connected to the reception at the time of finger input is converted into a voltage signal by the current-voltage conversion circuit. , A capacitance type that is converted into a DC signal by a multiplication circuit synchronized with the sin signal and a low-pass filter, digitizes the DC signal by an AD conversion circuit, and specifies a touch position of a finger or an input pen by an arithmetic processing unit. In the input device, in the case of the finger input, the finger input is selected by the selection circuit, the x-side electrode is connected to the reception by the transmission / reception switching circuit, and the y-side electrode is connected to the transmission. The touch position is detected, and in the case of an input pen, the input pen is selected by the selection circuit, and both the x and y electrodes are connected to the transmission by the transmission and reception switching circuits, and the reception circuit connected to the input pen. The first gist is to detect the indicated position, and the transmission / reception switching circuit connected to the electrodes arranged in a grid of x and y with the insulator in between, and the selection to select the input pen and x electrode. It has a circuit, and at finger input, it measures the current linked to the change in capacitance between the x and y electrodes, and at the input pen, the x and y electrodes and the capacitance of the pen tip conductor are coupled. In order to measure the current, a sin signal is applied from the synchronous transmission circuit to the electrode connected to the transmission, while the current measured by the electrode or input pen connected to the reception at the time of finger input is current-voltage. It is converted into a voltage signal by a conversion circuit, converted into a DC signal by a multiplication circuit synchronized with the sin signal and a low-pass filter, digitized by an AD conversion circuit, and by a arithmetic processing unit of a finger or an input pen. In the capacitance type input device that specifies the touch position, in the case of the finger input, the finger input is selected by the selection circuit, the x-side electrode is connected to the transmission by the transmission / reception switching circuit, and the y-side The electrode is connected to the reception to detect the finger touch position, and in the case of an input pen, the input pen is selected by the selection circuit, and both the x and y electrodes are connected to the reception by the transmission and reception switching circuits. From the transmitter circuit connected to the input pen The second gist is to detect the indicated position by a receiving circuit in which both the x and y electrodes are connected to the signal.

The present invention has a transmission / reception switching circuit connected to electrodes arranged in a grid of x and y with an insulator in between, and a selection circuit for selecting an input pen and an x electrode. In order to measure the current linked to the change in capacitance between the x and y electrodes, and to measure the capacitance-coupled current between the x and y electrodes and the pen tip conductor with the input pen, the transmission is performed. A sin signal is applied to the connected electrodes from the synchronous transmission circuit, while the current measured by the electrode or input pen connected to the reception at the time of finger input is converted into a voltage signal by the current-voltage conversion circuit. , A capacitance type that is converted into a DC signal by a multiplication circuit synchronized with the sin signal and a low-pass filter, digitizes the DC signal by an AD conversion circuit, and specifies a touch position of a finger or an input pen by an arithmetic processing unit. In the input device, in the case of the finger input, the finger input is selected by the selection circuit, the x-side electrode is connected to the reception by the transmission / reception switching circuit, and the y-side electrode is connected to the transmission. The touch position is detected, and in the case of an input pen, the input pen is selected by the selection circuit, and both the x and y electrodes are connected to the transmission by the transmission and reception switching circuits, and the reception circuit connected to the input pen. The first gist is to detect the indicated position, and the transmission / reception switching circuit connected to the electrodes arranged in a grid of x and y with the insulator in between, and the selection to select the input pen and x electrode. It has a circuit, and at finger input, it measures the current linked to the change in capacitance between the x and y electrodes, and at the input pen, the x and y electrodes and the capacitance of the pen tip conductor are coupled. In order to measure the current, a sin signal is applied from the synchronous transmission circuit to the electrode connected to the transmission, while the current measured by the electrode or input pen connected to the reception at the time of finger input is current-voltage. It is converted into a voltage signal by a conversion circuit, converted into a DC signal by a multiplication circuit synchronized with the sin signal and a low-pass filter, digitized by an AD conversion circuit, and by a arithmetic processing unit of a finger or an input pen. In the capacitance type input device that specifies the touch position, in the case of the finger input, the finger input is selected by the selection circuit, the x-side electrode is connected to the transmission by the transmission / reception switching circuit, and the y-side The electrode is connected to the reception to detect the finger touch position, and in the case of an input pen, the input pen is selected by the selection circuit, and both the x and y electrodes are connected to the reception by the transmission and reception switching circuits. From the transmitter circuit connected to the input pen The second gist is to detect the indicated position with a receiving circuit in which both the x and y electrodes are connected to the signal. Therefore, when using the touch switch function with a finger, switch the x electrode to the receiving side and x and y. The current linked to the change in capacitance between the electrodes is measured, and the coordinate detection function using the input pen switches the x and y electrodes to the transmitting side and measures the capacitance-coupled current of the pen tip conductor. Therefore, the xy electrode can be shared and used, and a switch panel having a simple structure can be realized. In addition, the operability is improved by providing a touch switch function with a finger and a coordinate detection function with an input pen.

Configuration diagram of the input device of the first embodiment Input device configuration diagram of the second embodiment Configuration diagram of the input device of the third embodiment Configuration diagram of the input device of the fourth embodiment Signal explanatory diagram of finger input of this embodiment Signal explanatory diagram of the input pen of this embodiment Explanatory drawing of phase difference and effective value of finger touch signal of this Example

The first embodiment of the present invention will be described with reference to FIG. The x-electrode 1 and the y-electrode 2 are arranged in a grid pattern with an insulator in between (shown), and this configuration is referred to as a switch panel 50. There is a transmission switching circuit 8 connected to the y electrode 2, an x reception switching circuit 9 and an x transmission switching circuit 10 connected to the x electrode 1, and a selection circuit for selecting the input pen 3 and the x reception switching circuit 9. There are six. The signal current measured from the X electrode 1 or the input pen 3 is selected by the selection circuit 6 and converted into a signal voltage by the current-voltage-voltage conversion circuit 7. Note that this signal voltage is an Asin (ωt + α), where ω is the angular frequency, t is the time, α is the phase difference, and A is the measured amplitude (= effective value).

The signal voltage Asin (ωt + α) is connected to the multiplication circuit 11 and the multiplication circuit 14. In the multiplication circuit 11, the signal voltage Asin (ωt + α) is multiplied by the sin (ωt) signal output from the synchronous transmission circuit 16. In the multiplication circuit 14, the signal voltage Asin (ωt + α) is multiplied by the cos (ωt) signal output from the synchronous transmission circuit 16. The sin (ωt) signal is connected to the y transmission switching circuit 8 and the x transmission switching circuit 10 in addition to the multiplication circuit 11. Further, the cos (ωt) signal output from the synchronous transmission circuit 16 is output with a phase difference of 90 degrees from the sin (ωt) signal.

The signal voltage from the multiplication circuit 11 is converted into a DC signal by the low-pass filter 12, and a signal of a specific frequency signal A / 2cos (α) is detected from the signals buried in noise.

Similarly, the signal voltage from the multiplication circuit 14 is converted into a DC signal by the low-pass filter 15, and a signal of a specific frequency signal A / 2sin (α) is detected from the signals buried in noise. The DC signalized A / 2cos (α) and A / 2sin (α) can be quantified by the AD converter built in the control unit 13 to obtain the effective value vector length A / 2, and the measurement can be performed. It becomes the magnitude of the signal.

The control unit 13 includes an AD converter that digitizes the DC signal described above, and also selects each of the y transmission switching circuit 8, the x reception switching circuit 9, the x transmission switching circuit 10, and the selection circuit 7. It includes a switching control unit for switching, a calculation processing unit and a storage unit for specifying the on / off of finger touch and the position of an input pen by performing calculation processing with the measured signal, and an interface unit for notifying the result to the outside. Further, in other embodiments, an AD converter, switching and selection control, arithmetic processing, storage, external output, and the like are similarly included.

The operation in the case of finger input will be described with reference to FIGS. 1 and 5. The sin (ωt) signal output from the synchronous transmission circuit 16 is sequentially connected to the y electrode 2 by the y transmission switching circuit 8 and applied. The x transmission switching circuit 10 is not connected to the x electrode 1, and the x reception switching circuit 9 is sequentially connected to the x electrode 1. At this time, the selection circuit 6 selects the x electrode 1 side.

FIG. 5 is an explanatory diagram of a finger input signal. The transmission signal 45 is applied to the y electrode 2 via the transmission switching circuit 41, and when the finger 4 touches the switch panel 50, a part of the current due to the capacitance coupling between the x electrode 1 and the y electrode 2 causes the human body impedance 5. The current (= signal current) flowing from the x electrode 1 to the ground via the x receiving electrode switching circuit 40 flows from the dotted line portion of the received signal 46 before the finger touches like the solid line portion of the received signal 46. Also becomes smaller.

In the control unit 13, the x electrode 1 and the y electrode intersect at the place where the difference between the electrostatically coupled signal current between the x electrode 1 and the y electrode 2 before the finger touch and the signal current touched by the finger 4 is maximized. Specify the position as the touch position.

FIG. 7 is an explanatory diagram of the phase difference and the effective value of the finger touch signal of this embodiment. The signal voltage Asin (ωt + α) is multiplied by the sin (ωt) signal output from the multiplication circuit 11 and the synchronous transmission circuit 16, and is converted into a DC signal by the low-pass filter 12. A signal of a specific frequency A / 2cos (α). And the cos (ωt) signal output from the multiplication circuit 14 and the synchronous transmission circuit 16, and the signal of the signal A / 2sin (α) of a specific frequency which is DC signalized by the low-pass filter 15 is graphed. Is shown in FIG.
The effective value of the signal is calculated from the two signal vectors. The effective value before the finger touches the switcher is a dotted line, and when the finger touches, each signal voltage A / 2cos (α) and A / 2sin (α) become smaller and the effective value becomes smaller as shown by the solid line. The operation in the case of pen input will be described with reference to FIGS. 1 and 6. The sin (ωt) signal output from the synchronous transmission circuit 16 is sequentially connected to the y electrode by the y transmission switching circuit 8 and applied. The x-reception switching circuit 9 is not connected to the x-electrode 1, and the x-transmission switching circuit 10 is sequentially connected to the x-electrode 1 for printing. The selection circuit 6 selects the input pen 3 side.
FIG. 6 is a signal explanatory diagram of the input pen. When the transmission signal 45 is applied to the x electrode 1 and the input pen 3 comes into contact with the switch panel 50, a current (= signal current) due to capacitance coupling is received between the x electrode 1 and the detection electrode 44 on the input pen 3. Like the solid line portion of 47, the signal is detected through the input pen 3 larger than the dotted line portion of the received signal 47 before the input pen 3 comes into contact with the input pen 3. The control unit 13 specifies the x-electrode 1 that maximizes the signal current.

Similarly, when the transmission signal 45 is applied to the y electrode 2 and the input pen 3 comes into contact with the switch panel 50, a current (= signal current) due to capacitance coupling is generated between the y electrode 2 and the detection electrode 44 on the input pen 3. Like the solid line portion of the received signal 47, the detection is detected through the input pen 3 larger than the dotted line portion of the received signal 47 before the input pen 3 comes into contact with the input pen 3. The control unit 13 specifies the y electrode 1 that maximizes the signal current.

The position where the input pen is in contact with the specified x-electrode 1 and y-electrode 2 is set. As a method of specifying the position in more detail, the maximum electrodes S2 of each electrode line of the x electrode 1 and the y electrode 3 and the signal currents S1 and S3 adjacent to each other are measured to calculate (S2-S1) / (S2-S3). It is also possible to determine the position between the electrodes from the ratio. However, S2> S1> S3.

A second embodiment of the present invention will be described with reference to FIG. The x-electrode 1 and the y-electrode 2 are arranged in a grid pattern with an insulator in between (shown), and this configuration is referred to as a switch panel 50. There is a transmission switching circuit 8 connected to the y electrode 2, an x reception switching circuit 9 and an x transmission switching circuit 10 connected to the x electrode 1, and a selection circuit for selecting the input pen 3 and the x reception switching circuit 9. There are six. The signal current measured from the X electrode 1 or the input pen 3 is selected by the selection circuit 6 and converted into a signal voltage by the current-voltage-voltage conversion circuit 7. Note that this signal voltage is an Asin (ωt + α), where ω is the angular frequency, t is the time, α is the phase difference, and A is the measured amplitude.

The phase adjusting circuit 17 converts the sin (ωt) signal output from the synchronous transmission circuit 18 into sin (ωt + α) adjusted to have the same phase (zero phase difference) as the signal voltage Asin (ωt + α). In the phase adjustment circuit 17, the adjustment values of the phase differences between the finger input and the pen input are set and stored in advance, and are reflected when the finger / pen is switched.

The multiplication circuit 11 multiplies the signal voltage Asin (ωt + α) by sin (ωt + α) adjusted in phase. The synchronous transmission circuit 18 is further connected to the y transmission switching circuit 8 and the x transmission switching circuit 10.

The signal voltage from the multiplication circuit 11 is converted into a DC signal by the low-pass filter 12, and a DC signal of signal A / 2 having a specific frequency is detected from the signals buried in noise. The DC signal of the A / 2 is the magnitude of the signal quantified and measured by the AD converter built in the control unit 13. The calculation formula of the multiplication device can be expressed as follows.

Asin (βt) × sin (βt) = (A / 2) (cos (2βt + cos (0)))
However, β is an angular frequency in which the phase difference from the signal voltage is set to zero by the synchronous transmission circuit 17.
The DC signal (A / 2) is obtained by removing the second harmonic from the combined signal of cos (2βt), which is the second harmonic, and the DC signal (A / 2) cos (0), using the low-pass filter 12. 2) The signal of cos (0) = A / 2 is measured.

In the second embodiment of the present invention, the detection signal can be directly measured in order to multiply the multiplication circuit 11 with a signal having the same phase as the signal voltage, and the arithmetic processing for obtaining the effective value as in the first embodiment. Is no longer needed.

The operation in the case of finger input and the operation of the input pen are the same as those in the first embodiment of the present invention.

A third embodiment of the present invention will be described with reference to FIG. The x-electrode 1 and the y-electrode 2 are arranged in a grid pattern with an insulator in between (shown), and this configuration is referred to as a switch panel 50. There is a reception switching circuit 22 connected to the y electrode 2, an x reception switching circuit 24 and an x transmission switching circuit 23 connected to the x electrode 1, and a selection circuit for selecting the input pen 3 and the x transmission switching circuit 23. There are 20. The signal current measured from the x electrode 1 and the y electrode 2 is converted into a signal voltage by the current-voltage-voltage conversion circuit 21. Note that this signal voltage is an Asin (ωt + α), where ω is the angular frequency, t is the time, α is the phase difference, and A is the measured amplitude.

The synchronous transmission circuit 29 outputs a sin (ωt) signal and a cos (ωt) signal. The sin (ωt) signal is connected to the selection circuit 20 and the multiplication circuit 25, and the cos (ωt) signal is connected to the multiplication circuit 27.

The signal voltage Asin (ωt + α) is connected to the multiplication circuit 25 and the multiplication circuit 27. In the multiplication circuit 25, the signal voltage Asin (ωt + α) is multiplied by the sin (ωt) signal output from the synchronous transmission circuit 29. In the multiplication circuit 27, the signal voltage Asin (ωt + α) is multiplied by the cos (ωt) signal output from the synchronous transmission circuit 16. The sin (ωt) signal is connected to the selection circuit 20 in addition to the multiplication circuit 25. Further, the cos (ωt) signal output from the synchronous transmission circuit 29 is output with a phase difference of 90 degrees from the sin (ωt) signal.

The signal voltage from the multiplication circuit 25 is converted into a DC signal by the low-pass filter 26, and a signal of a specific frequency signal A / 2cos (α) is detected from the signals buried in noise.
Similarly, the signal voltage from the multiplication circuit 27 is converted into a DC signal by the low-pass filter 28, and a signal of a specific frequency signal A / 2sin (α) is detected from the signals buried in noise. The DC signalized A / 2cos (α) and A / 2sin (α) can be quantified by the AD converter built in the control unit 13 to obtain the effective value vector length A / 2, and the measurement can be performed. It becomes the magnitude of the signal.

The operation in the case of finger input will be described. The x transmission switching circuit 23 is selected by the selection circuit 20, and the sin (ωt) signal output from the synchronous transmission circuit 29 is sequentially connected to the x electrode 1 by the x transmission switching circuit 23 and applied. At this time, the x reception switching circuit 24 is not connected to the x electrode 1. The y reception switching circuit 22 is sequentially connected to the y electrode 2.

When the transmission signal sin (wt) is applied to the x electrode 1 and the finger 4 touches the switch panel 50, a part of the current due to the electrostatic capacitance coupling between the x electrode 1 and the y electrode 2 goes to the ground via the human body impedance 5. The current (= signal current) that flows, that is, flows from the y electrode 2 through the y receiving electrode switching circuit 22, becomes smaller than the received signal before the finger touches.

In the control unit 13, the x-electrode 1 and the y-electrode intersect at the place where the difference between the electrostatically coupled signal current between the x-electrode 1 and the y-electrode 2 before the finger touch and the signal current touched by the finger 4 is maximized. Specify the position as the touch position.

Next, the operation in the case of pen input will be described. The input pen 3 is selected by the selection circuit 20, and the sin (ωt) signal output from the synchronous transmission circuit 29 is applied to the input pen 3. It is sequentially connected to the y electrode by the y reception switching circuit 22. The x transmission switching circuit 23 is not connected to the x electrode 1, and the x reception switching circuit 24 is sequentially connected to the x electrode 1. When the input pen 3 comes into contact with the switch panel 50, the current (= signal current) due to capacitance coupling between the x electrode 1 and the input pen 3 is larger than the received signal before the input pen 3 comes into contact with the input pen 3 via the x electrode 1. Is detected. The control unit 13 specifies the x-electrode 1 that maximizes the signal current.

Similarly, it is sequentially connected to the y electrode 2 by the y reception switching circuit 22, and when the input pen 3 comes into contact with the switch panel 50, a current (= signal current) due to capacitance coupling between the y electrode 2 and the input pen 3 is applied to the input pen. It is detected through the y electrode 2 that is larger than the received signal before the 3 abuts. The control unit 13 specifies the y electrode 2 that maximizes the signal current. The position where the input pen is in contact with the specified x-electrode 1 and y-electrode 2 is set.

A fourth embodiment of the present invention will be described with reference to FIG. The x-electrode 1 and the y-electrode 2 are arranged in a grid pattern with the insulator in between (shown in the figure), and the reception switching circuit 22 connected to the y-electrode 2 has this configuration as the switch panel 50. There is an x reception switching circuit 24 and an x transmission switching circuit 23 connected to the x electrode 1, and there is a selection circuit 20 for selecting the input pen 3 and the x transmission switching circuit 23. The signal current measured from the x electrode 1 and the y electrode 2 is converted into a signal voltage by the current-voltage-voltage conversion circuit 21. Note that this signal voltage is an Asin (ωt + α), where ω is the angular frequency, t is the time, α is the phase difference, and A is the measured amplitude.

The synchronous transmission circuit 30 outputs sin (ωt) and is connected to the selection circuit 20 and the phase adjustment circuit 31. The phase adjustment circuit 31 converts the sin (ωt) signal output from the synchronous transmission circuit 30 into sin (ωt + α) adjusted to have the same phase (zero phase difference) as the signal voltage Asin (ωt + α). In the phase adjustment circuit 31, the adjustment value of each phase difference between finger input and pen input is set and stored in advance, and is reflected when switching between finger and pen.

The multiplication circuit 25 multiplies the signal voltage Asin (ωt + α) by sin (ωt + α) adjusted in phase. The synchronous transmission circuit 30 is further connected to the input pen 3 and the x transmission switching circuit 23 via the selection circuit 20.

The signal voltage from the multiplication circuit 25 is converted into a DC signal by the low-pass filter 26, and a DC signal of signal A / 2 having a specific frequency is detected from the signals buried in noise. The DC signal of the A / 2 is the magnitude of the signal quantified and measured by the AD converter built in the control unit 13. The calculation formula of the multiplication device can be expressed as follows.

Asin (βt) × sin (βt) = (A / 2) (cos (2βt + cos (0)))
However, β is an angular frequency in which the phase difference from the signal voltage is set to zero by the synchronous transmission circuit 17.
The DC signal (A / 2) is obtained by removing the second harmonic from the combined signal of cos (2βt), which is the second harmonic, and the DC signal (A / 2) cos (0), using the low-pass filter 26. 2) The signal of cos (0) = A / 2 is measured.

In the fourth embodiment of the present invention, the detection signal can be directly measured in order to multiply the multiplication circuit 25 with a signal having the same phase as the signal voltage, and the arithmetic processing for obtaining the effective value as in the third embodiment. Is no longer needed.

The operation in the case of finger input and the operation of the input pen are the same as those in the third embodiment of the present invention.

Hereinafter, the present invention will be described with reference to Examples. The present invention is not limited to the following examples, but includes various modifications within the technical scope of the present invention.
(Example 1)
The configuration of the switch panel 50 will be described with reference to FIG. The y electrode 2 and the wiring pattern for connecting to an external circuit are printed on the surface of the PET (polyethylene terephthalate) film with silver paste or ITO (indium tin oxide). The width of the y electrode 2 was 3 mm, and the y electrodes 2 were arranged at a pitch of 9 mm so as to be parallel to each other at equal intervals. Next, on the back surface of the PET film, the x electrode 1 and the wiring pattern for connecting to the external circuit are printed with silver paste. The width of the x-electrode was 3 mm, and the x-electrodes were arranged in a grid pattern at a pitch of 9 mm so as to be perpendicular to the y-electrode 2 so as to be parallel to each other at equal intervals.

The width of the x and y electrodes is 3 mm, and the electrode pitch is 9 mm. However, if the width is such that capacitance can be obtained, it can be 3 mm or less, or 3 mm or more, but the signal change is increased at the time of finger input. Therefore, the width of each electrode at the intersection of the x and y electrodes is reduced so that the overall electrode width is smaller than that of the y electrode 2 arranged on the front surface in order to detect a large signal from the x electrode 1 on the back surface when using the input pen. It is desirable to make it larger. Further, although the base material is a PET film, a glass base material or a glass epoxy base material may be used in addition to the above, and any material capable of forming a conductive material in the insulator can be used.

The synchronous transmission circuit 16 outputs the sin (ωt) signal and the cos (ωt) signal at a frequency of 400 kHz. The sin (ωt) signal is also connected to the y transmission switching circuit 8 and the x transmission switching circuit 10, and when the input pen 3 is used, the input pen 3 is selected by the selection circuit 6 and sequentially connected to the x electrode 1 and the y electrode 2. Apply. In the case of finger input, the x reception switching circuit 9 is selected by the selection circuit 6 and sequentially applied to the y electrode 2, and the x transmission switching circuit 10 is not connected but is sequentially connected to the x reception switching circuit 9.
The signal voltage Asin (ωt + α) to be measured is connected to the multiplication circuit 11 and the multiplication circuit 14. In the multiplication circuit 11, the signal voltage Asin (ωt + α) is multiplied by the sin (ωt) signal output from the synchronous transmission circuit 16. In the multiplication circuit 14, the signal voltage Asin (ωt + α) is multiplied by the cos (ωt) signal output from the synchronous transmission circuit 16. The signal voltage from the multiplication circuit 11 is converted into a DC signal by the low-pass filter 12, and a signal of a specific frequency signal A / 2cos (α) is detected from the signals buried in noise.

Similarly, the signal voltage from the multiplication circuit 14 is converted into a DC signal by the low-pass filter 15, and a signal of a specific frequency signal A / 2sin (α) is detected from the signals buried in noise. The DC signalized A / 2cos (α) and A / 2sin (α) can be quantified by the AD converter built in the control unit 13 to obtain the effective value vector length A / 2, and the measurement can be performed. It becomes the magnitude of the signal.

In the configuration of the first embodiment, by arranging the signal amplification circuit inside the input pen 3, the measured signal can be amplified and output to the current-voltage conversion circuit 7, so that the ratio of noise to the signal is improved and the position is accurate. Can be detected. Even if the signal to be measured has a phase difference (α), it can be obtained by the effective value A calculation process, so even if the phase difference (α) of the signal measured by the finger input and the input pen is different, the ambient temperature Even if the phase difference (α) changes due to the change in, the finger input or the position of the input pen can be accurately detected.
(Example 2)
This will be described with reference to FIG. The configuration of the switch panel 50 is the same as that of (Example 1).
The synchronous transmission circuit 18 outputs sin (ωt) having a frequency of 400 kHz and is connected to the y transmission switching circuit 8 and the x transmission switching circuit 10 and the phase adjustment circuit 17. When the input pen 3 is used, the input pen 3 is used by the selection circuit 6. Is selected and applied to the x-electrode 1 and the y-electrode 2 in sequence. In the case of finger input, the x reception switching circuit 9 is selected by the selection circuit 6 and sequentially applied to the y electrode 2, and the x transmission switching circuit 10 is not connected but is sequentially connected to the x reception switching circuit 9.

The signal voltage Asin (ωt + α) to be measured is connected to the multiplication circuit 11. The phase adjusting circuit 17 converts the sin (ωt) signal output from the synchronous transmission circuit 18 into sin (ωt + α) adjusted to have the same phase (zero phase difference) as the signal voltage Asin (ωt + α). The multiplication circuit 11 multiplies the signal voltage Asin (ωt + α) by sin (ωt + α) adjusted in phase.
The signal voltage from the multiplication circuit 11 is converted into a DC signal by the low-pass filter 12, and a DC signal of signal A / 2 having a specific frequency is detected from the signals buried in noise. The DC signal of the A / 2 is the magnitude of the signal quantified and measured by the AD converter built in the control unit 13.

In the configuration of the second embodiment, by arranging the signal amplification circuit inside the input pen 3, the measured signal can be amplified and output to the current-voltage conversion circuit 7, so that the ratio of noise to the signal is improved and the position is accurate. Can be detected. Further, since the signal measured by the phase adjustment circuit 17 is multiplied by the sin (ωt + α) adjusted to the same phase as the phase difference (α) by the multiplication circuit 11, the output result of the multiplication circuit 17 is the signal voltage to be measured. It becomes the effective value A of, and it is not necessary to calculate the effective value vector length, and the finger input or the position of the input pen can be detected at high speed.
(Example 3)
This will be described with reference to FIG. The configuration of the switch panel 50 is the same as that of (Example 1).
The synchronous transmission circuit 29 outputs a sin (ωt) signal and a cos (ωt) signal having a frequency of 400 kHz. The sin (ωt) signal is connected to the selection circuit 20 and the multiplication circuit 25, and the cos (ωt) signal is connected to the multiplication circuit 27.

The y reception switching circuit 22 is connected to the y electrode 2, the x transmission switching circuit 23 and the x reception switching circuit 24 are connected to the x electrode 1. When the input pen 3 is used, the input pen 3 is selected by the selection circuit 20. The y reception switching circuit 22 is sequentially connected to the y electrode 2, the x transmission switching circuit 23 is not connected, and the x reception switching circuit 24 is sequentially connected to the x electrode 1. In the case of finger input, the x transmission switching circuit 23 is selected by the selection circuit 20, the y reception switching circuit 22 is sequentially connected to the y electrode 2, the x reception switching circuit 24 is not connected, and the x transmission switching circuit 23 is sequentially x. Connect to electrode 1.

The signal voltage Asin (ωt + α) to be measured is connected to the multiplication circuit 25 and the multiplication circuit 27. In the multiplication circuit 25, the signal voltage Asin (ωt + α) is multiplied by the sin (ωt) signal output from the synchronous transmission circuit 29. In the multiplication circuit 27, the signal voltage Asin (ωt + α) is multiplied by the cos (ωt) signal output from the synchronous transmission circuit 29. The signal voltage from the multiplication circuit 25 is converted into a DC signal by the low-pass filter 26, and a signal of a specific frequency signal A / 2cos (α) is detected from the signals buried in noise.
Similarly, the signal voltage from the multiplication circuit 27 is converted into a DC signal by the low-pass filter 28, and a signal of a specific frequency signal A / 2sin (α) is detected from the signals buried in noise. The DC signalized A / 2cos (α) and A / 2sin (α) can be quantified by the AD converter built in the control unit 13 to obtain the effective value vector length A / 2, and the measurement can be performed. It becomes the magnitude of the signal.

In the configuration of the third embodiment, since the sin (ωt) signal from the synchronous transmission circuit 29 is connected to the input pen 3 and output, noise intrusion from the input pen 3 is less than that of the first embodiment, and the noise immunity is improved. Even if the signal to be measured has a phase difference (α), it can be obtained by the effective value A calculation process, so even if the phase difference (α) of the signal measured by the finger input and the input pen is different, the ambient temperature Even if the phase difference (α) changes due to the change in, the finger input or the position of the input pen can be accurately detected.
(Example 4)
This will be described with reference to FIG. The configuration of the switch panel 50 is the same as that of (Example 1).
The synchronous transmission circuit 30 outputs sin (ωt) having a frequency of 400 kHz, and is connected to the selection circuit 20 and the phase adjustment circuit 31. The y reception switching circuit 22 is connected to the y electrode 2, the x transmission switching circuit 23 and the x reception switching circuit 24 are connected to the x electrode 1. When the input pen 3 is used, the input pen 3 is selected by the selection circuit 20. The y reception switching circuit 22 is sequentially connected to the y electrode 2, the x transmission switching circuit 23 is not connected, and the x reception switching circuit 24 is sequentially connected to the x electrode 1. The signal voltage Asin (ωt + α) to be measured is connected to the multiplication circuit 25.

The phase adjustment circuit 31 converts the sin (ωt) signal output from the synchronous transmission circuit 30 into sin (ωt + α) adjusted to have the same phase (zero phase difference) as the signal voltage Asin (ωt + α). The multiplication circuit 25 multiplies the signal voltage Asin (ωt + α) by sin (ωt + α) adjusted in phase. The signal voltage from the multiplication circuit 25 is converted into a DC signal by the low-pass filter 26, and a DC signal of signal A / 2 having a specific frequency is detected from the signals buried in noise. The DC signal of the A / 2 is the magnitude of the signal quantified and measured by the AD converter built in the control unit 13.

In the configuration of the fourth embodiment, since the sin (ωt) signal from the synchronous transmission circuit 30 is connected to the input pen 3 and output, noise intrusion from the input pen 3 is less than that of the second embodiment, and noise immunity is improved. Further, since the signal measured by the phase adjustment circuit 31 is multiplied by the sin (ωt + α) adjusted to the same phase as the phase difference (α) by the multiplication circuit 11, the output result of the multiplication circuit 25 is the signal voltage to be measured. It becomes the effective value A of, and it is not necessary to calculate the effective value vector length, and the finger input or the position of the input pen can be detected at high speed.

When using the input pen as in the present invention, a sin (ωt) signal is sequentially applied to the x electrode and the y electrode, and the capacitance is coupled between the input pen and the x and y electrodes to detect the position signal, and the finger is used. In the case of input, the touch position is detected by reducing the signal from the electrostatically coupled signal between the x and y electrodes via the finger, so the input pen and finger input position identification method are different, so use them at the same time. Can be done. It is also possible to prioritize, for example, when using the input pen, finger input can be invalidated or vice versa, which greatly improves usability.

1 x electrode 2 y electrode 3 input pen 4 fingers (hand)
5 Human impedance 6 Selection circuit 7 Current-voltage conversion circuit 8 y Transmission switching circuit 9 x Reception switching circuit 10 x Transmission switching circuit 11 Multiplication circuit 12 Low pass filter 13 Control unit 14 Multiplication circuit 15 Low pass filter 16 Synchronous transmission circuit 17 Phase adjustment circuit 18 Synchronous transmission circuit 20 Selection circuit 21 Current-voltage conversion circuit 22 y Reception switching circuit 23 x Transmission switching circuit 24 x Reception switching circuit 25 Multiplication circuit 26 Low pass filter 27 Multiplication circuit 28 Low pass filter 29 Synchronous transmission circuit 30 Synchronous transmission circuit 31 Phase Adjustment circuit 40 Reception switching circuit 41 Transmission switching circuit 42 Transmission switching circuit 43 Transmission switching circuit 44 Detection electrode 45 Transmission signal 46 Reception signal 47 Reception signal 50 Switch panel

Claims (4)

It has a transmission / reception switching circuit connected to electrodes arranged in a grid of x and y with an insulator in between, and a selection circuit for selecting an input pen and an x electrode. In finger input, the x and y are described. In order to measure the current linked to the change in capacitance between the electrodes of, and to measure the capacitance-coupled current between the x and y electrodes and the pen tip conductor in the input pen, the electrodes connected to the transmission. A sin signal is applied from the synchronous transmission circuit to, while the current measured by the electrode or input pen connected to the reception at the time of finger input is converted into a voltage signal by the current-voltage conversion circuit, and the sin signal is converted into a voltage signal. In a capacitance type input device, which is converted into a DC signal by a multiplication circuit and a low-pass filter synchronized with the above, digitizes the DC signal by an AD conversion circuit, and specifies a touch position of a finger or an input pen by an arithmetic processing unit. In the case of the finger input, the finger input is selected by the selection circuit, the x-side electrode is connected to the reception by the transmission / reception switching circuit, the y-side electrode is connected to the transmission, and x from the x-electrode. The finger touch position is detected when the signal current flowing through the reception switching circuit becomes smaller than the signal current before the finger touch, and in the case of the input pen, the input pen is selected by the selection circuit and the transmission is performed. In the reception switching circuit, both the x and y electrodes are connected to transmission , the input pen is connected to the reception circuit, and the signal current between the detection on the x electrode and the input pen is larger than the received signal before the input pen abuts. A capacitance type input device characterized in that an indicated position is detected when detected via an electrode . It has a transmission / reception switching circuit connected to electrodes arranged in a grid of x and y with an insulator in between, and a selection circuit for selecting an input pen and an x electrode. In finger input, the x and y are described. In order to measure the current linked to the change in capacitance between the electrodes of, and to measure the capacitance-coupled current between the x and y electrodes and the pen tip conductor in the input pen, the electrodes connected to the transmission. A sin signal is applied from the synchronous transmission circuit to, while the current measured by the electrode or input pen connected to the reception at the time of finger input is converted into a voltage signal by the current-voltage conversion circuit, and the sin signal is converted into a voltage signal. In a capacitance type input device, which is converted into a DC signal by a multiplication circuit and a low-pass filter synchronized with the above, digitizes the DC signal by an AD conversion circuit, and specifies a touch position of a finger or an input pen by an arithmetic processing unit. In the case of the finger input, the finger input is selected in the selection circuit, the x-side electrode is connected to the transmission in the transmission / reception switching circuit, the y-side electrode is connected to the reception, and x reception is performed from the x electrode. The finger touch position is detected when the current flowing through the switching circuit becomes smaller than the received signal before the finger touch, and in the case of the input pen, the input pen is selected by the selection circuit, and the transmission is performed. In the reception switching circuit, both the x and y electrodes are connected to reception , the input pen is connected to the transmission circuit , and the signal current between the x electrode and the detection on the input pen is larger than the received signal before the input pen abuts. A capacitance type input device characterized in that the indicated position is detected when it is detected via . Synchronized sin signal and cos signal are generated by the synchronous transmission circuit, the sin signal is connected to the transmitting side, a current-voltage conversion circuit is connected to the receiving side, and the detected signal and the sin signal are connected. 1 and 2, wherein a multiplication circuit for multiplying the cos signal is provided, and the output signal of the multiplication circuit is converted into a DC signal by the low-pass filter circuit, and the finger touch signal and the input pen detection signal are measured. Capacitive input device. A synchronized sin signal is generated by the synchronous transmission circuit, the sin signal is connected to the transmitting side, a current-voltage conversion circuit is connected to the receiving side, and the detected signal and the sin signal are phase-adjusted. A claim for measuring a finger touch signal and an input pen detection signal in which a multiplication circuit for multiplying a fixed phase signal adjusted to a specific phase by a circuit is provided and the output signal of the multiplication circuit is converted into a DC signal by a low-pass filter circuit. 1 or the capacitance type input device according to claim 2.

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