Integrated circuit and sensor controller

Abstract

To improve an SNR of a pen signal.SOLUTION: An integrated circuit according to the present invention is an integrated circuit connected to an EMR sensor. A receiving-side coil of the EMR sensor is composed of a plurality of first loop coils. The integrated circuit includes a plurality of differential amplifiers each having a first input terminal and a second input terminal, first wiring connecting one end of each of the plurality of first loop coils to the first input terminal of a corresponding differential amplifier, second wiring connecting the other end of each of the plurality of first loop coils to the second input terminal of the corresponding differential amplifier, and a first switch element provided between power supply wiring to which a predetermined power supply potential is supplied and the first wiring.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an integrated circuit and a sensor controller, and particularly to an integrated circuit and a sensor controller used together with an EMR sensor.

Background Art

[0002] As one of the methods for detecting the position of an electromagnetic induction pen in a panel surface such as a tablet terminal, an electromagnetic induction method (EMR method) is known. A position detection device using the EMR method includes a sensor for pen detection (hereinafter referred to as "EMR sensor") arranged in the panel surface and a sensor controller connected to the EMR sensor. The EMR sensor includes a transmission-side coil composed of a plurality of Tx coils arranged side by side in the y direction and a reception-side coil composed of a plurality of Rx coils arranged side by side in the x direction. The sensor controller sequentially sends out an alternating magnetic field from the plurality of Tx coils, and each time, receives a reflection signal (hereinafter referred to as "pen signal") transmitted by the electromagnetic induction pen at each Rx coil, thereby detecting the position of the electromagnetic induction pen (hereinafter referred to as "pen position") and receiving data transmitted by the electromagnetic induction pen (hereinafter referred to as "pen data"). Examples of the EMR sensor are disclosed in Patent Documents 1 to 3.

[0003] Patent Document 2 discloses an example of an EMR sensor using a loop coil as the Rx coil. Both ends of the Rx coil of Patent Document 2 are connected to two input terminals of a differential amplifier that outputs a pen signal. Patent Document 3 discloses an example of an EMR sensor using a linear electrode (hereinafter referred to as "linear electrode") instead of the Rx coil.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

[0005] By the way, there are several connection methods between each Rx coil constituting the receiving-side coil of the EMR sensor and the sensor controller. Specifically, there are a differential method of connecting both ends of the Rx coil to the sensor controller, a single-ended method of connecting one end of the Rx coil to the sensor controller and grounding the other end, a bundled input method of connecting a plurality of Rx coils in series to the sensor controller, and the like. Each has its own merits, but a conventional position detection device is limited to only one of them. Therefore, it has been required to be able to switch the connection method between each Rx coil and the sensor controller.

[0006] Therefore, one object of the present invention is to provide an integrated circuit capable of switching the connection method between the receiving-side coil of the EMR sensor and the sensor controller.

[0007] Further, the inventor of the present application is considering using, as the receiving-side coil of the EMR sensor, a coil (hereinafter referred to as a "comb-shaped coil") configured by connecting a large number of wirings (hereinafter referred to as "comb teeth portions") extending in the y direction to a single wiring (hereinafter referred to as a "base portion") extending in the x direction instead of the plurality of Rx coils described above. One end of each comb tooth portion is connected to the base portion, and the other end is connected to the sensor controller. According to the research of the inventor of the present application, the sensor controller receives the pen signal by regarding the other ends of two adjacent comb tooth portions as both ends of the Rx coil. Actually, although each of the two comb tooth portions is connected to other comb tooth portions via the base portion, it is possible to receive the pen signal as if an Rx coil is formed by the two comb tooth portions and the portion of the base portion connecting them. Therefore, by using the comb-shaped coil, it is possible to detect the pen position in the same manner as when using a plurality of Rx coils.

[0008] However, on the other hand, the comb-shaped coil has a problem that the detection accuracy of the pen position becomes rough. This is because the configuration of the comb-shaped coil is equivalent to that virtual loop coils each constituted by two adjacent comb teeth portions are arranged at intervals in the x direction.

[0009] Therefore, another object of the present invention is to provide an integrated circuit capable of improving the detection accuracy of the pen position when using a comb-shaped coil as the receiving coil of the EMR sensor.

[0010] Also, while the alternating magnetic field is being transmitted from the Tx coil, this alternating magnetic field appears in the Rx coil. Therefore, after stopping the transmission of the alternating magnetic field from the Tx coil, the sensor controller receives the pen signal in the Rx coil. However, due to the influence of the time constant of the Rx coil, the influence remains in the Rx coil even after the transmission of the alternating magnetic field from the Tx coil has stopped, deteriorating the SNR (Signal to Noise Ratio) of the pen signal.

[0011] Therefore, yet another object of the present invention is to provide an integrated circuit and a sensor controller capable of improving the SNR of the pen signal.

[0012] In addition, the inventor of the present application is considering using, as the receiving-side coil of the EMR sensor, a coil (hereinafter referred to as a "comb-shaped coil") configured by connecting a number of wirings (hereinafter referred to as "comb teeth") extending in the y direction to a single wiring (hereinafter referred to as a "base") extending in the x direction, instead of the plurality of Rx coils described above. One end of each comb tooth is connected to the base, and the other end is connected to the sensor controller. According to the research of the inventor of the present application, the sensor controller can receive the pen signal by regarding the other ends of two adjacent comb teeth as both ends of the Rx coil. Even though each of the two comb teeth is actually connected to other comb teeth via the base, the sensor controller can receive the pen signal as if the Rx coil is formed by the two comb teeth and the portion of the base connecting them. Therefore, by using the comb-shaped coil, it is possible to detect the pen position in the same manner as when using a plurality of Rx coils.

[0013] However, on the other hand, the comb-shaped coil has a problem that the detection accuracy of the pen position becomes rough. This is because the configuration of the comb-shaped coil is equivalent to that in which virtual loop coils formed by two adjacent comb teeth are arranged at intervals in the x direction.

[0014] Therefore, still another object of the present invention is to provide an integrated circuit and a sensor controller capable of improving the detection accuracy of the pen position when using a comb-shaped coil as the receiving-side coil of the EMR sensor.

[0015] Also, when using a linear electrode instead of the Rx coil as in Patent Document 2, the sign of the pen signal is reversed between the linear electrode on one side in the x direction and the linear electrode on the other side in the x direction as viewed from the pen position, and a sign transition occurs in the vicinity of the pen position. Therefore, there is a problem that the reception intensity of the pen signal becomes weak in the vicinity of the pen position.

[0016] Accordingly, yet another object of the present invention is to provide an integrated circuit and a sensor controller capable of enhancing the reception intensity of a pen signal when a linear electrode is used instead of an Rx coil.

[0017] In addition, in a conventional position detection device, when an electromagnetic induction pen is tilted with respect to the panel surface, depending on the azimuth angle of the electromagnetic induction pen, the peak position of the pen signal received by the Rx coil may deviate from the position of the original pen tip. Then, the detection accuracy of the pen position deteriorates, so improvement has been required.

[0018] Accordingly, yet another object of the present invention is to provide a sensor controller capable of detecting the position with high accuracy even when the electromagnetic induction pen is tilted with respect to the panel surface.

[0019] In recent years, a foldable display (foldable display) has emerged, and in this foldable display too, it is required to be able to detect the position of the electromagnetic induction pen. However, in a foldable display, a conductive hinge component is used to achieve folding, and since the magnetic field is disturbed by this hinge component, there has been a problem that the reception intensity of the pen signal becomes weak in the vicinity of the hinge component, that is, in the vicinity of the folding line.

[0020] Accordingly, yet another object of the present invention is to provide an integrated circuit and a sensor controller capable of enhancing the reception intensity of a pen signal in the vicinity of the folding line of a foldable display.

Means for Solving the Problems

[0021] An integrated circuit according to a first aspect of the present invention is an integrated circuit connected to a receiving-side coil of an EMR sensor, wherein the receiving-side coil has a plurality of ends along a first side of a touch surface, the plurality of ends including a first end and a second end, a differential amplifier having a first input terminal and a second input terminal, and a switch group configured to switch a connection destination of the first end among the second input terminal, the second end, a ground terminal, and the first input terminal.

[0022] An integrated circuit according to a second aspect of the present invention is the integrated circuit according to the first aspect, wherein the receiving-side coil is a comb-shaped coil having the plurality of ends, and the switch group switches between a first state in which the first end is connected to the second input terminal and a second state in which the first end is connected to the first input terminal in a time-division manner.

[0023] An integrated circuit according to a third aspect of the present invention is an integrated circuit connected to an EMR sensor, wherein the receiving-side coil of the EMR sensor is constituted by a plurality of first loop coils, a plurality of differential amplifiers each having a first input terminal and a second input terminal, a first wiring connecting one end of each of the plurality of first loop coils to the first input terminal of the corresponding differential amplifier, a second wiring connecting the other end of each of the plurality of first loop coils to the second input terminal of the corresponding differential amplifier, and a first switch element provided between a power supply wiring to which a predetermined power supply potential is supplied and the first wiring.

[0024] The sensor controller according to the third aspect of the present invention is a sensor controller connected to the EMR sensor via an integrated circuit according to the third aspect of the present invention. The plurality of first loop coils each extend in a first direction and are arranged side by side in a second direction intersecting the first direction. The transmission-side coils of the EMR sensor are each composed of a plurality of second loop coils extending in the second direction and arranged side by side in the first direction. The integrated circuit connects one end and the other end of the (2n - 1)th (n is a natural number) first loop coil from one end side in the second direction among the plurality of first loop coils to the first input terminal and the second input terminal of the corresponding differential amplifier, while disconnecting one end and the other end of the 2nth first loop coil from the first input terminal and the second input terminal of the corresponding differential amplifier in a first state. In a second state, one end and the other end of the 2nth first loop coil from one end side in the second direction among the plurality of first loop coils are connected to the first input terminal and the second input terminal of the corresponding differential amplifier, while one end and the other end of the (2n - 1)th first loop coil are disconnected from the first input terminal and the second input terminal of the corresponding differential amplifier. The integrated circuit further has a switch circuit configured to be switchable between the first state and the second state. By sequentially passing current through each of the plurality of second loop coils, an alternating magnetic field is sent from the EMR sensor. When the current is passed through the (2m - 1)th (m is a natural number) second loop coil from one end side in the first direction among the plurality of second loop coils, the switch circuit is set to the first state. When the current is passed through the 2mth loop coil from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the second state, and the sensor controller receives the pen signals output from each of the plurality of differential amplifiers.

[0025] An integrated circuit according to a fourth aspect of the present invention is an integrated circuit connected to an EMR sensor, wherein a receiving-side coil of the EMR sensor is a comb-shaped coil having a configuration in which a plurality of comb teeth portions each extending in a first direction are connected to a base portion extending in a second direction intersecting the first direction at one end thereof, a plurality of differential amplifiers each having a first input terminal and a second input terminal, and a switch circuit configured to be switchable between a first state in which the other end of the (2n - 1)th (n is a natural number) comb tooth portion and the other end of the 2nth comb tooth portion from one end side in the second direction among the plurality of comb tooth portions are respectively connected to the first input terminal and the second input terminal of the same differential amplifier, and a second state in which the other end of the 2nth comb tooth portion and the other end of the (2n + 1)th comb tooth portion from one end side in the second direction among the plurality of comb tooth portions are respectively connected to the first input terminal and the second input terminal of the same differential amplifier.

[0026] A sensor controller according to a fourth aspect of the present invention is a sensor controller connected to the EMR sensor via the integrated circuit according to the fourth aspect of the present invention, wherein a transmitting-side coil of the EMR sensor is composed of a plurality of loop coils each extending in the second direction and arranged side by side in the first direction, and an alternating magnetic field is transmitted from the EMR sensor by sequentially passing a current through each of the plurality of loop coils. When the current is passed through the (2m - 1)th (m is a natural number) loop coil from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the first state, and when the current is passed through the 2mth loop coil from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the second state, so as to receive a pen signal output from each of the plurality of differential amplifiers.

[0027] An integrated circuit according to a fifth aspect of the present invention is an integrated circuit connected to an EMR sensor, wherein receiving side coils of the EMR sensor each extend in a first direction and are configured by a plurality of linear electrodes arranged side by side in a second direction intersecting the first direction, and a plurality of differential amplifiers each having a first input terminal and a second input terminal, and wiring connecting, to the first input terminal and the second input terminal of the same differential amplifier, each of an end of the (2n - k)-th (k is an odd natural number, n is a natural number greater than k / 2) linear electrode from one end side in the second direction among the plurality of linear electrodes and an end of the 2n-th linear electrode.

[0028] A sensor controller according to a fifth aspect of the present invention is a sensor controller connected to the EMR sensor via an integrated circuit according to the fifth aspect of the present invention, wherein transmitting side coils of the EMR sensor each extend in the second direction and are configured by a plurality of loop coils arranged side by side in the first direction, and a switching circuit is caused to be in the first state when the current is passed through the (2m - 1)-th (m is a natural number) loop coil from one end side in the first direction among the plurality of loop coils to send an alternating magnetic field from the EMR sensor by sequentially passing the current through each of the plurality of loop coils, and the switching circuit is caused to be in the second state when the current is passed through the 2m-th loop coil from one end side in the first direction among the plurality of loop coils, and a pen signal output from each of the plurality of differential amplifiers is received.

[0029] A sensor controller according to a sixth aspect of the present invention is a sensor controller connected to an EMR sensor having a plurality of loop coils, and adds, with different weightings, a pen signal received in a first loop coil among the plurality of loop coils and pen signals received in each of one or more other loop coils in the vicinity of the first loop coil among the plurality of loop coils, and derives the position of an electromagnetic induction pen using an added pen signal obtained by the addition.

[0030] An integrated circuit according to a seventh aspect of the present invention is an integrated circuit connected to an EMR sensor, wherein a receiving side coil of the EMR sensor is a comb-shaped coil having a configuration in which a plurality of comb teeth portions extending in a first direction are connected to a base portion extending in a second direction intersecting the first direction at one end of each of the comb teeth portions, a receiving circuit for a pen signal transmitted by an electromagnetic induction pen, and a selection circuit that selects two of the plurality of comb teeth portions and connects the selected two comb teeth portions to the receiving circuit, the plurality of comb teeth portions having first to fourth comb teeth portions in order from one side in the second direction, the selection circuit performing the selection so that a first state of selecting the first and third comb teeth portions among the plurality of comb teeth portions and a second state of selecting the second and fourth comb teeth portions among the plurality of comb teeth portions appear in order, a distance between the first comb tooth portion and the third comb tooth portion and a distance between the second comb tooth portion and the fourth comb tooth portion are both a first distance, and a distance between the first comb tooth portion and the second comb tooth portion is a second distance shorter than the first distance.

[0031] A sensor controller according to a seventh aspect of the present invention is further in the integrated circuit according to a seventh aspect of the present invention, wherein the plurality of comb teeth portions have a fifth comb tooth portion on the other side in the second direction of the fourth comb tooth portion, and the selection circuit is a sensor controller connected to the EMR sensor via an integrated circuit that performs the selection so that the first state, the second state, and a third state of selecting the third comb tooth portion and the fifth comb tooth portion appear in order, and controls the selection circuit so that the first state, the second state, and the third state appear in order.

Advantages of the Invention

[0032] According to a first aspect of the present invention, it is possible to switch the connection method between the receiving side coil of the EMR sensor and the sensor controller by controlling the switch group.

[0033] According to a second aspect of the present invention, reception of the pen signal in the first state and reception of the pen signal in the second state can be performed in a time-division manner. Therefore, the interval of the virtual loop coil can be effectively set to zero, and thus it becomes possible to improve the detection accuracy of the pen position when a comb-shaped coil is used as the reception-side coil of the EMR sensor.

[0034] According to a third aspect of the present invention, each first loop coil can be precharged by turning on the first switch element. Therefore, the influence of the alternating magnetic field sent from the transmission-side coil can be excluded from the reception-side coil, and it becomes possible to improve the SNR of the pen signal.

[0035] According to a fourth aspect of the present invention, reception of the pen signal in the first state and reception of the pen signal in the second state can be performed in a time-division manner. Therefore, the interval of the virtual loop coil can be effectively set to zero, and thus it becomes possible to improve the detection accuracy of the pen position when a comb-shaped coil is used as the reception-side coil of the EMR sensor.

[0036] According to a fifth aspect of the present invention, pen signals having opposite signs are strengthened by a differential amplifier. Therefore, it becomes possible to increase the reception intensity of the pen signal when a linear electrode is used as the Rx coil in the vicinity of the pen position.

[0037] According to a sixth aspect of the present invention, the position of the electromagnetic induction pen is derived using an added pen signal obtained by adding the pen signals received by a plurality of loop coils with different weightings. Therefore, even if the electromagnetic induction pen is tilted with respect to the panel surface, its position can be detected with high accuracy.

[0038] According to a seventh aspect of the present invention, the virtual loop coil is shifted by a distance shorter than the distance between the two comb teeth portions constituting the virtual loop coil. Therefore, it becomes possible to increase the reception intensity of the pen signal in the vicinity of the folding line of the foldable display.

Brief Description of the Drawings

[0039]

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Best Mode for Carrying Out the Invention

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0041] FIG. 1 is a diagram showing the configuration of a position detection system 1 according to a first embodiment of the present invention. As shown in the figure, the position detection system 1 is configured to include an electromagnetic induction pen 2 and a position detection device 3. Among these, the electromagnetic induction pen 2 is a pen corresponding to position detection by the EMR method, and is configured to have a resonance circuit including a coil and a capacitor inside.

[0042] The position detection device 3 is a device configured to be able to detect the position of the electromagnetic induction pen 2 in a touch surface 3a (panel surface) by the EMR method. Inside the touch surface 3a, a plurality of loop coils LCx (Rx coils) which are reception side coils of the EMR sensor and a plurality of loop coils LCy (Tx coils) which are transmission side coils of the EMR sensor are arranged. In addition to this, the position detection device 3 includes a switch circuit 30, a sensor controller 31, and a host processor 32. A typical example of the position detection device 3 is a tablet terminal or a notebook personal computer whose display surface also serves as the touch surface 3a, but the position detection device 3 may be configured by a digitizer or the like that does not have a display surface.

[0043] Both the illustrated x and y directions are directions within the touch surface 3a and are orthogonal to each other. The plurality of loop coils LCx are each formed to extend in the y direction and are arranged side by side in the x direction. On the other hand, the plurality of loop coils LCy are each formed to extend in the x direction and are arranged side by side in the y direction. Note that both the loop coils LCx and LCy may be arranged so as to overlap with other adjacent loop coils LCx and LCy, and in that case, they are three-dimensionally formed using via conductors or the like. Each loop coil LCx and each loop coil LCy are both connected to the switch circuit 30 at both ends. The end portions of each loop coil LCx are arranged along a side E1 which is one side of the rectangular touch surface 3a.

[0044] The switch circuit 30 is an assembly (switch group) of switches composed of a plurality of switches for switching the connections between a plurality of loop coils LCx and for switching the connections between the plurality of loop coils LCx and LCy and the sensor controller 31. The switch circuit 30 may be configured as an integrated circuit alone or may be provided within the same integrated circuit as the sensor controller 31. The switching state of the switch circuit 30 is controlled by the sensor controller 31.

[0045] The sensor controller 31 is an integrated circuit having a function of detecting the position of the electromagnetic induction pen 2 (pen position) within the touch surface 3a by the EMR method. The sensor controller 31 controls the connection state with the loop coils LCx and LCy under the control of the switch circuit 30, thereby sequentially supplying an alternating current to each of the plurality of loop coils LCy and receiving the pen signal generated in each loop coil LCx each time. Then, the sensor controller 31 is configured to derive the pen position based on the pen signal received in this way and to receive the pen data transmitted by the electromagnetic induction pen 2.

[0046] More specifically, when the sensor controller 31 starts supplying an alternating current to any one of the loop coils LCy, the transmission of an alternating magnetic field starts from that loop coil LCy. When the coil of the electromagnetic induction pen 2 enters this alternating magnetic field, an electromotive force is generated at both ends thereof, and the capacitor of the electromagnetic induction pen 2 is charged. Subsequently, when the sensor controller 31 stops supplying the alternating current to the loop coil LCy, an alternating magnetic field (pen signal) is transmitted from the coil of the electromagnetic induction pen 2 by the power stored in the capacitor of the electromagnetic induction pen 2.

[0047] Here, the electromagnetic induction pen 2 is configured to be able to transmit pen data such as a pen pressure value indicating the pressure applied to the pen tip and on / off information indicating the on / off state of a switch provided on the surface, using a pen signal. That is, the capacitor constituting the resonance circuit of the electromagnetic induction pen 2 is configured such that its capacitance changes according to the value of the pen data. When the capacitance of the capacitor changes, the resonance frequency of the resonance circuit changes according to the amount of change. Therefore, the frequency of the alternating magnetic field transmitted from the coil changes according to the value of the pen data. The electromagnetic induction pen 2 is configured to frequency-modulate the alternating magnetic field transmitted from the coil with the pen data, utilizing such properties of the resonance circuit.

[0048] The pen signal transmitted from the coil of the electromagnetic induction pen 2 is received by each loop coil LCx. The sensor controller 31 obtains the intensity of the pen signal for each combination of the loop coil LCy and the loop coil LCx by receiving the pen signal in each loop coil LCx each time while changing the loop coil LCy that supplies an alternating current under the control of the switch circuit 30. Then, based on the intensities obtained, the intensity distribution of the pen signal within the touch surface 3a is derived, and the apex is detected as the pen position. Further, the sensor controller 31 obtains the pen data by detecting the change in the frequency of the pen signal received with the strongest intensity. The sensor controller 31 is configured to supply the position detected and the data obtained as described above to the host processor 32 each time.

[0049] Here, the detection of the pen position by the sensor controller 31 is executed by either of two modes: a global scan and a local scan. The global scan is a process executed when the pen position has not been detected yet. The sensor controller 31 executes the above-described series of processes using all the loop coils LCx, LCy. Thereby, the sensor controller 31 can detect the electromagnetic induction pen 2 over the entire touch surface 3a.

[0050] On the one hand, local scanning is a process that is executed when there is a detected pen position. In this case, the sensor controller 31 executes the above-described series of processes using only the loop coils LCx and LCy located near the previously detected pen position. By doing so, the time required for one position detection can be shortened, so the sensor controller 31 can detect the pen position at a higher frequency than global scanning.

[0051] Also, the sensor controller 31 is configured to select any one of the differential method, single-ended method, and bundled input method described above for receiving the pen signal in each loop coil LCx. This selection may be made at the manufacturing stage of the sensor controller 31 or the position detection device 3, or may be made by the user during use. In one example, the sensor controller 31 selects the bundled input method when it is shown by the pen pressure value included in the latest received pen data that the electromagnetic induction pen 2 is hovering (the pen tip is not in contact with the touch surface 3a), and selects the differential method or the single-ended method when it is shown that the pen is touching (the pen tip is in contact with the touch surface 3a). The sensor controller 31 controls the switch circuit 30 according to the result of the selection, and as a result, reception of the pen signal in the selected method is realized. The specific details of the control of the switch circuit 30 by the sensor controller 31 will be described in detail later with reference to FIGS. 2 to 5.

[0052] The host processor 32 is the central processing unit of the position detection device 3 that plays a role in executing the operating system and various applications of the position detection device 3 by executing a program read from a memory (not shown). The processes executed by the host processor 32 according to the program include various processes performed using the pen position and pen data supplied from the sensor controller 31. These various processes include, for example, moving the cursor displayed on the display surface, generating stroke data indicating the trajectory of the electromagnetic induction pen 2 within the touch surface, and the like. Among these, regarding the stroke data, the host processor 32 also performs processes such as rendering and displaying the generated stroke data, generating and recording digital ink including the generated stroke data, and transmitting the generated digital ink to an external device according to a user's instruction.

[0053] Figures 2 to 5 are diagrams showing the internal configuration of the switch circuit 30. These diagrams show only the portions related to the reception of the pen signal in each loop coil LCx among the internal configuration of the switch circuit 30. Hereinafter, with reference to these diagrams, the internal configuration of the switch circuit 30 and the specific content of the control of the switch circuit 30 performed by the sensor controller 31 to realize each of the differential method, single-ended method, and bundled input method will be described in detail.

[0054] For the sake of simplicity in explanation, Figures 2 to 5 show only two loop coils LCx 1 , LCx 2 , but it goes without saying that the actual position detection device 3 has more loop coils LCx. Hereinafter, both ends of the loop coil LCx 1 are referred to as ends T 11 , T 12 , and both ends of the loop coil LCx 2 are referred to as ends T 21 , T 22 .

[0055] Referring first to FIG. 2, the switch circuit 30 is configured to include a plurality of differential amplifiers 40 and a switch group including a plurality of switches 50 to 55. The differential amplifier 40 is provided for each loop coil LCx. The switches 50, 51, and 52 are single-pole double-throw switches, and the switches 53 and 54 are single-pole triple-throw switches, each provided for each loop coil LCx. Further, the switch 55 is a single-pole double-throw switch and is provided for every two adjacent loop coils LCx. In the following description, as necessary, for the configuration corresponding to the loop coil LCx 1 a subscript "1" is added to the right side of the reference numeral, and for the configuration corresponding to the loop coil LCx 2 a subscript "2" is added to the right side of the reference numeral, and for the configuration corresponding to the loop coil LCx 1 , LCx 2 a subscript "12" is added to the right side of the reference numeral for the configuration corresponding to both, so as to distinguish each configuration from other configurations in some cases.

[0056] Each differential amplifier 40 has a non-inverting input terminal, an inverting input terminal, and an output terminal, and is an amplifier circuit (differential amplifier) that amplifies the potential difference between the non-inverting input terminal and the inverting input terminal and outputs the amplified potential difference from the output terminal as an output voltage with respect to the ground potential. The output terminal of each differential amplifier 40 is supplied to the sensor controller 31 as a pen signal.

[0057] The common terminal of the switch 50 1 is connected to the end T 11 , one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 11 . The common terminal of the switch 51 1 is connected to the end T 12 , one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 12 . The common terminal of the switch 52 1 is connected to the node n 12 , one selection terminal is connected to the node n 11 , and the other selection terminal is connected to the second selection terminal of the switch 53 1 . The common terminal of the switch 53 1 is connected to the differential amplifier 401 is connected to the non-inverting input terminal, the first selection terminal is connected to node n 11 is connected, and the third selection terminal is connected to the ground terminal. The common terminal of switch 54 1 is connected to the inverting input terminal of differential amplifier 40 1 is connected, the first selection terminal is connected to node n 12 is connected, the second selection terminal is connected to node n 21 to be described later, and the third selection terminal is connected to the ground terminal.

[0058] Switch 50 2 The common terminal is connected to end T 21 is connected, one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 21 . The common terminal of switch 51 2 is connected to end T 22 is connected, one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 22 . The common terminal of switch 52 2 is connected to node n 22 is connected, one selection terminal is connected to node n 21 is connected, and the other selection terminal is connected to the second selection terminal of switch 53 2 . The common terminal of switch 53 2 is connected to the non-inverting input terminal of differential amplifier 40 2 is connected, the first selection terminal is connected to node n 21 is connected, and the third selection terminal is connected to the ground terminal. The common terminal of switch 54 2 is connected to the inverting input terminal of differential amplifier 40 2 is connected, the first selection terminal is connected to node n 22 is connected, and the third selection terminal is connected to the ground terminal. Although not shown, the second selection terminal of switch 54 2 is connected to the other selection terminal of switch 50 corresponding to the other loop coil LCx adjacent to loop coil LCx 1 on the opposite side of loop coil LCx 2 .

[0059] The common terminal of switch 55 is connected to end T 12is connected, and one of the selection terminals is the end T 21 is connected. The other selection terminal of the switch 55 is not connected to anywhere, and thus the switch 55 may be considered as a single-pole single-throw switch.

[0060] With the above configuration, the switch circuit 30 12 (the first end) can switch the connection destination between the inverting input terminal (the second input terminal) of the differential amplifier 40 1 and either the end T 21 (the second end), the ground terminal, and the non-inverting input terminal (the first input terminal) of the differential amplifier 40 1 . By controlling this switching, the sensor controller 31 realizes the reception of the pen signal in each of the differential mode, single-ended mode, and bundled input mode. This will be described in detail below.

[0061] FIG. 2 shows the state of the switch circuit 30 after being controlled by the sensor controller 31 that has selected the differential mode. In this case, the sensor controller 31 connects the other selection terminals to the common terminal in each of the switches 50 and 51, and connects the first selection terminals to the common terminal in each of the switches 53 and 54. The switches 52 and 55 are in the off state (or the state where the other selection terminals are selected). As a result, as shown by the broken line in FIG. 2, both ends of the corresponding loop coil LCx are connected to each differential amplifier 40. For example, for the differential amplifier 40 1 , the non-inverting input terminal is connected to the end T 1 of the loop coil LCx 11 , and the inverting input terminal is connected to the end T 1 of the loop coil LCx 12 . According to the differential mode, common-mode noise can be removed from the pen signal received by each loop coil LCx, and an effect that the signal strength of the pen signal received by each loop coil LCx becomes larger than that in the single-ended mode described later can be obtained.

[0062] Figure 3 shows the state of the switch circuit 30 after being controlled by the sensor controller 31 that has selected the single-ended method. In this case, the sensor controller 31 connects the other selection terminal to the common terminal at the switch 50, connects the first selection terminal to the common terminal at the switch 53, connects one selection terminal to the common terminal at the switch 51, and connects the third selection terminal to the common terminal at the switch 54. The switches 52 and 55 are in the open state (or the state in which the other selection terminals are selected), as in the case of Figure 2. As a result, as shown by the dashed line in Figure 3, for each differential amplifier 40, only the non-inverting input terminal is connected to one end of the corresponding loop coil LCx, and the inverting input terminal is connected to the ground terminal. Also, the other end of each loop coil LCx is connected to the ground terminal. For example, the differential amplifier 40 1 has its non-inverting input terminal connected to the loop coil LCx 1 at the end T 11 and its inverting input terminal connected to the ground terminal, and the end T 1 of the loop coil LCx 12 is connected to the ground terminal. According to the single-ended method, the effect is obtained that the sensor controller 31 can receive the pen signal without connecting the differential amplifier 40 to both ends of the loop coil LCx.

[0063] Figures 4 and 5 show the state of the switch circuit 30 after being controlled by the sensor controller 31 that has selected the bundled input method. In this case, the sensor controller 31 controls the switch circuit 30 so that for each loop coil LCy, the first state shown in Figure 4 and the second state shown in Figure 5 are realized in a time-division manner.

[0064] First, referring to Figure 4, the first state is a state in which two adjacent loop coils LCx are connected in series between the non-inverting input terminal and the inverting input terminal of each differential amplifier 40. Specifically explaining with reference to Figure 4, the sensor controller 31, in order to realize the first state, at the switches 50 1 , 51 2 connects the other selection terminals to the common terminals, and at the switch 522 ,55 12 In this case, one of the selection terminals is connected to the common terminal, and switch 53 1 In this case, the first selection terminal is connected to the common terminal, and switch 54 1 In this case, the second selection terminal is connected to the common terminal, while switch 50 2 ,51 1 ,52 1 ,53 2 ,54 2 is set to the off state. As a result, as shown by the dashed line in FIG. 4, two loop coils LCx 1 ,LCx 2 are connected in series between the non-inverting input terminal and the inverting input terminal of differential amplifier 40 1 . The same applies to other loop coils LCx (not shown).

[0065] Next, referring to FIG. 5, the second state is obtained by shifting the combination of the two loop coils LCx connected in series to each differential amplifier 40 by one position in the x direction as compared with the first state. In addition to this shift, the content of the control of switch circuit 30 performed by sensor controller 31 to realize the second state is the same as in the case of the first state.

[0066] According to the bundled input method, since two loop coils LCx are connected in series, the inductance is doubled, and as a result, the effect that the reception intensity of the pen signal increases is obtained. However, since it is necessary to perform the first state shown in FIG. 4 and the second state shown in FIG. 5 in a time-division manner, compared with the differential method and the single-ended method, twice the time is required to receive the pen signal. As described above, when the sensor controller 31 determines that the electromagnetic induction pen 2 is hovering based on the pen pressure value included in the latest received pen data, the bundled input method is selected, and when it is determined that the pen is touching, the differential method or the single-ended method is selected. In this way, when hovering, where the distance between the coil in the electromagnetic induction pen 2 and the touch surface 3a is large and the reception intensity of the pen signal tends to be small, the bundled input method is used to increase the reception intensity of the pen signal, and when touching, where a sufficiently large reception intensity can be obtained, the differential method or the single-ended method is used to shorten the time required to receive the pen signal, thereby realizing an adaptive switching of the connection method.

[0067] As described above, according to the position detection system 1 according to the present embodiment, by controlling the switch group in the switch circuit 30 from the sensor controller 31, it is possible to switch the connection method between the reception-side coil of the EMR sensor and the sensor controller 31 among the differential method, the single-ended method, and the bundled input method. Therefore, the sensor controller 31 can detect the pen position and acquire pen data while maximizing the advantages of each method.

[0068] FIG. 6 is a diagram showing the configuration of the position detection system 1 according to the second embodiment of the present invention. The position detection system 1 according to the present embodiment is different from the position detection system 1 according to the first embodiment in that a comb-shaped coil CCx including a base PB and a plurality of comb teeth PT is used as the receiving coil of the EMR sensor instead of the plurality of loop coils LCx. Accordingly, the internal configuration of the switch circuit 30 and the content of the control of the switch circuit 30 by the sensor controller 31 are also different from those of the position detection system 1 according to the first embodiment. Since other points are the same as those of the position detection system 1 according to the first embodiment, the following description will focus on the differences from the position detection system 1 according to the first embodiment.

[0069] As shown in FIG. 6, the comb-shaped coil CCx is a coil configured by connecting a plurality of comb teeth PT, each of which is a wiring extending in the y direction, to a base PB that is a single wiring extending in the x direction. One end of each comb tooth PT is connected to the base PB, and the other end is connected to the switch circuit 30. The other ends of the respective comb teeth PT are arranged along a side E1 that is one side of the rectangular touch surface 3a.

[0070] FIGS. 7 and 8 are diagrams showing the internal configuration of the switch circuit 30 according to the present embodiment. These figures show only the portion related to the reception of the pen signal in the comb-shaped coil CCx among the internal configuration of the switch circuit 30. Hereinafter, with reference to these figures, a method for the sensor controller 31 to receive the pen signal using the comb-shaped coil CCx will be described in detail.

[0071] For simplicity of explanation, FIGS. 7 and 8 show only four comb teeth PT 1 ~PT 4 , but it goes without saying that the actual comb-shaped coil CCx has more comb teeth PT. Hereinafter, the other ends (the ends opposite to the ends connected to the base PB) of the comb teeth PT 1 ~PT 4 are referred to as ends T 1 ~T 4 .

[0072] Referring first to FIG. 7, the switch circuit 30 according to the present embodiment includes a plurality of differential amplifiers 40 and a switch group including a plurality of switches 60 to 62. The differential amplifier 40 is provided at a ratio of one for two comb teeth portions PT. The switch 60 is a single-pole double-throw switch, and the switch 62 is a single-pole triple-throw switch, and each is provided for each comb tooth portion PT. Further, the switch 61 is a single-pole double-throw switch and is provided at a ratio of one for two comb teeth portions PT. In the following description, as necessary, for the configuration corresponding to the comb tooth portion PT 1 , a subscript "1" is added to the right side of the reference numeral, and for the configuration corresponding to the comb tooth portion PT 2 , a subscript "2" is added to the right side of the reference numeral, and for the configuration corresponding to the comb tooth portion PT 3 , a subscript "3" is added to the right side of the reference numeral, and for the configuration corresponding to the comb tooth portion PT 4 , a subscript "4" is added to the right side of the reference numeral, and for the configuration corresponding to the comb tooth portion PT 1 , PT 2 , a subscript "12" is added to the right side of the reference numeral for the configuration corresponding to both, and for the configuration corresponding to the comb tooth portion PT 3 , PT 4 , a subscript "34" is added to the right side of the reference numeral for the configuration corresponding to both, so as to distinguish each configuration from other configurations in some cases.

[0073] The common terminal of the switch 60 1 is connected to the end T 1 , one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 1 . The same applies to the switches 60 2 to 60 4 . The common terminal of the switch 60 2 is connected to the end T 2 , one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 2 . The common terminal of the switch 60 3 is connected to the end T 3 , one selection terminal is connected to the ground terminal, and the other selection terminal constitutes the illustrated node n 3 . The common terminal of the switch 60 4 is connected to the end T 4is connected, one selection terminal is connected to the ground terminal, and the other selection terminal is the node n shown in the figure 4 to form

[0074] The common terminal of switch 61 12 is connected to node n 2 One selection terminal is connected to node n 1 The other selection terminal is connected to the second selection terminal of switch 62 1 . The common terminal of switch 62 1 is connected to the non-inverting input terminal of differential amplifier 40 12 The first selection terminal is connected to node n 1 The third selection terminal is connected to the ground terminal. The common terminal of switch 62 2 is connected to the inverting input terminal of differential amplifier 40 12 The first selection terminal is connected to node n 2 The second selection terminal is connected to node n 3 The third selection terminal is connected to the ground terminal

[0075] The common terminal of switch 61 34 is connected to node n 4 One selection terminal is connected to node n 3 The other selection terminal is connected to the second selection terminal of switch 62 3 . The common terminal of switch 62 3 is connected to the non-inverting input terminal of differential amplifier 40 34 The first selection terminal is connected to node n 3 The third selection terminal is connected to the ground terminal. The common terminal of switch 62 4 is connected to the inverting input terminal of differential amplifier 40 34 The first selection terminal is connected to node n 4 The third selection terminal is connected to the ground terminal. Although not shown, the second selection terminal of switch 62 4 is connected to the other selection terminal of switch 60 corresponding to another comb tooth part PT adjacent to the comb tooth part PT 3 on the opposite side of 4 the comb tooth part PT

[0076] The switch circuit 30, with the above configuration, has the end T 2 (the first end) connected to the inverting input terminal (the second input terminal) of the differential amplifier 40 12 and the non-inverting input terminal (the first input terminal) of the differential amplifier 40 1 and plays a role of switching between them. By controlling this switching, the sensor controller 31 receives the pen signal while switching between the first state in which the end T 2 is connected to the inverting input terminal of the differential amplifier 40 12 and the second state in which the end T 2 is connected to the non-inverting input terminal of the differential amplifier 40 12 in a time-division manner. This will be described in detail below.

[0077] FIG. 7 shows the first state of the switch circuit 30. As shown in the figure, in the first state, the end T 1 of the comb tooth portion PT 1 is connected to the non-inverting input terminal of the differential amplifier 40 12 , and the end T 2 of the comb tooth portion PT 2 is connected to the inverting input terminal of the differential amplifier 40 12 . Also, the end T 3 of the comb tooth portion PT 3 is connected to the non-inverting input terminal of the differential amplifier 40 34 , and the end T 4 of the comb tooth portion PT 4 is connected to the inverting input terminal of the differential amplifier 40 34 . The same applies to the other comb tooth portions PT not shown. As a result, as shown by the dashed line in FIG. 7, one virtual loop coil is formed by the portions connecting two adjacent comb tooth portions PT and the base PB. Hereinafter, the virtual loop coil thus formed is referred to as a "virtual loop coil". Each virtual loop coil is connected through the base PB, but it has been found by the research of the inventor of the present application that this does not substantially affect the reception characteristics of the pen signal.

[0078] FIG. 8 shows the second state of the switch circuit 30. As shown in the figure, in the second state, the end T 2 of the comb tooth portion PT2 is connected to the non-inverting input terminal of the differential amplifier 40 12 and the end T of the comb-shaped part PT 3 is connected to the inverting input terminal of the differential amplifier 40. The end T of the comb-shaped part PT 3 is connected to the inverting input terminal of the differential amplifier 40 12 and the end T of the comb-shaped part PT 1 is connected to the inverting input terminal of the differential amplifier 40. The end T of the comb-shaped part PT 1 is on the opposite side of the comb-shaped part PT 2 and is connected to another differential amplifier 40 adjacent to the differential amplifier 40 on the opposite side together with the end of another comb-shaped part PT adjacent to the comb-shaped part PT 1 on the opposite side of the differential amplifier 40 34 Similarly, the end T of the comb-shaped part PT 12 is connected to the differential amplifier 40. The same applies to other comb-shaped parts PT not shown. As a result, as shown by the dashed line in FIG. 8, similar to the case of FIG. 7, one virtual loop coil is formed by the two adjacent comb-shaped parts PT and the base PB and the portion connecting them, but the combination of the two comb-shaped parts PT constituting each virtual loop coil is shifted by one comb-shaped part PT in the x direction compared to the case of FIG. 7. Even in the second state, each virtual loop coil is connected through the base PB, but similar to the first state, it has no substantial influence on the reception characteristics of the pen signal. 4 is connected to the differential amplifier 40 4 together with the end of another comb-shaped part PT adjacent to the comb-shaped part PT 3 on the opposite side of the comb-shaped part PT 4 on the opposite side of the differential amplifier 40 34 When receiving the pen signal depending only on either the first state shown in FIG. 7 or the second state shown in FIG. 8, since the interval in the x direction of the virtual loop coil becomes wide, the detection accuracy of the pen position in the x direction becomes rough. According to the switch circuit 30 according to the present embodiment, the sensor controller 31 can execute reception of the pen signal in the first state and reception of the pen signal in the second state for each loop coil LCy in a time-division manner. Therefore, overall, the interval of the virtual loop coil can be made zero. Therefore, it can be said that it is possible to improve the detection accuracy of the pen position when using the comb-shaped coil CCx as the receiving coil on the receiving side of the EMR sensor.

[0079]

[0080] ​ As described above, according to the position detection system 1 according to the present embodiment, reception of the pen signal in the first state and reception of the pen signal in the second state can be executed in a time-division manner. Therefore, the interval between the virtual loop coils can be effectively set to zero, so that it is possible to improve the detection accuracy of the pen position when the comb-shaped coil CCx is used as the reception-side coil of the EMR sensor.

[0081] Here, in the present embodiment, an example in which one comb tooth portion PT is connected to one input terminal of the differential amplifier 40 has been described, but a plurality of comb tooth portions PT may be connected. Hereinafter, two modified examples adopting such a connection will be described.

[0082] FIG. 9 and FIG. 10 are diagrams showing the first state and the second state of the switch circuit 30 according to the first modified example of the present embodiment, respectively. This modified example is an example in which two comb tooth portions PT are connected to one input terminal of the differential amplifier 40. In these figures, the detailed configuration within the switch circuit 30 is not shown, and only the connection state between each comb tooth portion PT and the differential amplifier 40 is shown. The switch circuit 30 according to this modified example has a differential amplifier 40 for four comb tooth portions PT at a ratio of one.

[0083] The sensor controller 31 according to this modified example first selects four comb tooth portions PT that make up the comb-shaped coil CCx one by one from one end side in the x direction, and sets four comb tooth portions PT as one set. In the example of FIG. 9, the comb tooth portions PT 1 ~PT 4 and the comb tooth portions PT 5 ~PT 8 each constitute one set. Then, the sensor controller 31 commonly connects two of the four comb tooth portions PT constituting each set to the non-inverting input terminal of the corresponding differential amplifier 40 from one end side in the x direction, and commonly connects the other two to the inverting input terminal of the corresponding differential amplifier 40. As a result, as shown in FIG. 9, a state (first state) in which four adjacent comb tooth portions PT are connected to one differential amplifier 40 is formed. This state is the end T of the comb tooth portion PT 4 ​4 A predetermined number (in this case, two) of ends including the (first end) are connected to the inverting input terminal of the first differential amplifier 40, and the comb teeth portion PT 5 end T 5 The state is such that the predetermined number of ends including the (second end) are connected to the non-inverting input terminal of the second differential amplifier 40.

[0084] Subsequently, the sensor controller 31 shifts each of the four comb teeth portions PT constituting each set one by one. FIG. 10 shows the state after this shift from the state of FIG. 9. As shown in the figure, in this case, the comb teeth portion PT 2 ~PT 5 and the comb teeth portion PT 6 ~PT 7 each form one set. Then, similar to the case of FIG. 9, the sensor controller 31 commonly connects two of the four comb teeth portions PT constituting each set to the non-inverting input terminal of the corresponding differential amplifier 40 from one end side in the x direction, and commonly connects the other two to the inverting input terminal of the corresponding differential amplifier 40. As a result, as shown in FIG. 10, a state (second state) is formed in which four adjacent comb teeth portions PT are connected to one differential amplifier 40. This state is such that the predetermined number of ends including the end T 4 (first end) of the comb teeth portion PT 4 and the end T 5 of the comb teeth portion PT 5 (second end) are connected to the inverting input terminal of the first differential amplifier 40, and the ends of the other predetermined number of comb teeth portions PT are connected to the non-inverting input terminal of the second differential amplifier 40.

[0085] The sensor controller 31 according to this modification example forms a set consisting of four comb teeth portions PT in four combinations by performing the same shift three times. Each time, two of the four comb teeth portions PT constituting each set are commonly connected to the non-inverting input terminals of the corresponding differential amplifiers 40 from one end side in the x direction, and the other two are commonly connected to the inverting input terminals of the corresponding differential amplifiers 40. By doing so, four adjacent comb teeth portions PT are connected to one differential amplifier 40 in four states including the above-described first state and second state. The sensor controller 31 according to this modification example receives the pen signals output from the respective differential amplifiers 40 in each of the four states thus formed. Then, using the received pen signals, the pen position is detected and pen data is acquired.

[0086] FIG. 11 and FIG. 12 are diagrams showing the first state and the second state of the switch circuit 30 according to the second modification example of the present embodiment, respectively. This modification example is an example in which four comb teeth portions PT are connected to one input terminal of the differential amplifier 40. Also in these figures, the detailed configuration within the switch circuit 30 is not shown, and only the connection state between each comb tooth portion PT and the differential amplifier 40 is shown. The switch circuit 30 according to this modification example has a differential amplifier 40 at a ratio of one for eight comb teeth portions PT.

[0087] The sensor controller 31 according to this modification example first selects eight comb teeth portions PT constituting the comb-shaped coil CCx one by one from one end side in the x direction, and sets eight comb teeth portions PT as one set. In the example of FIG. 11, the comb teeth portions PT 1 ~PT 8 constitute one set. Then, the sensor controller 31 commonly connects four of the eight comb teeth portions PT constituting each set to the non-inverting input terminals of the corresponding differential amplifiers 40 from one end side in the x direction, and commonly connects the other four to the inverting input terminals of the corresponding differential amplifiers 40. As a result, as shown in FIG. 11, a state (first state) in which eight adjacent comb teeth portions PT are connected to one differential amplifier 40 is formed. This state is the end T of the comb tooth portion PT 8 8 ​A predetermined number (in this case, four) of ends including the (first end) are connected to the inverting input terminal of the first differential amplifier 40, and the comb teeth part PT 9 The end T of 9 A state is established in which the predetermined number of ends including the (second end) are connected to the non-inverting input terminal of the second differential amplifier 40.

[0088] Subsequently, the sensor controller 31 shifts each of the eight comb teeth parts PT that make up each set one by one. FIG. 12 shows the state after this shift from the state of FIG. 11. As shown in the figure, in this case, the comb teeth part PT 2 ~PT 10 will form one set. Then, similar to the case of FIG. 11, the sensor controller 31 commonly connects four out of the eight comb teeth parts PT that make up each set to the non-inverting input terminal of the corresponding differential amplifier 40 from one end side in the x direction, and commonly connects the other four to the inverting input terminal of the corresponding differential amplifier 40. As a result, as shown in FIG. 12, a state (second state) is formed in which eight adjacent comb teeth parts PT are connected to one differential amplifier 40. This state is such that the ends T of the comb teeth part PT 8 (first end) and the ends T of the comb teeth part PT 8 (first end) and the ends T of the comb teeth part PT 9 The end T of 9 (second end) are connected to the inverting input terminal of the first differential amplifier 40, and the ends of the other predetermined number of comb teeth parts PT are connected to the non-inverting input terminal of the second differential amplifier 40.

[0089] The sensor controller 31 according to this modification forms a set consisting of eight comb teeth portions PT in eight combinations by performing the same shift seven times. Each time, four out of the eight comb teeth portions PT constituting each set are commonly connected to the non-inverting input terminals of the corresponding differential amplifiers 40 from one end side in the x direction, and the other four are commonly connected to the inverting input terminals of the corresponding differential amplifiers 40. By doing so, eight adjacent comb teeth portions PT are connected to one differential amplifier 40 in eight states including the above-described first state and second state. The sensor controller 31 according to this modification receives the pen signals output from the respective differential amplifiers 40 in each of the eight states thus formed. Then, using the received pen signals, the pen position is detected and pen data is acquired.

[0090] As shown in the two modifications described above, according to the position detection system 1 according to the present embodiment, even when a plurality of comb teeth portions PT are connected to one input terminal of the differential amplifier 40, reception of pen signals in a plurality of connection states can be executed in a time-division manner. Therefore, it is possible to improve the detection accuracy of the pen position when using the comb-shaped coil CCx as the reception-side coil of the EMR sensor. Further, according to these modifications, since a plurality of comb teeth portions PT are connected to one input terminal of the differential amplifier 40, it is possible to increase the reception intensity of the pen signal as compared with the present embodiment.

[0091] Next, the position detection system 1 according to the third embodiment of the present invention will be described. The position detection system 1 according to the present embodiment is different from the first embodiment in terms of the internal configuration of the switch circuit 30. Since it is the same as the position detection system 1 according to the first embodiment in other respects, the following description will focus on the differences from the position detection system 1 according to the first embodiment.

[0092] FIG. 13 is a diagram showing the internal configuration of the switch circuit 30 according to the present embodiment. The figure shows only the configuration related to the illustrated loop coil LCx. Also shown in the figure are each one loop coil LCx, LCy, and the sensor controller 31.

[0093] As shown in FIG. 13, the switch circuit 30 according to the present embodiment includes, for each loop coil LCx, a differential amplifier 40, wirings L1 and L2, and a switch group including switch elements S1, S2, T1, and T2.

[0094] The differential amplifier 40 has a non-inverting input terminal, an inverting input terminal, and an output terminal, and is an amplifier circuit (differential amplifier) that amplifies the potential difference between the non-inverting input terminal and the inverting input terminal, and outputs the amplified potential difference from the output terminal as an output voltage with respect to the ground potential. The output signal of the differential amplifier 40 is supplied to the sensor controller 31 as a pen signal PS.

[0095] The wiring L1 is a wiring that connects one end of the loop coil LCx to the non-inverting input terminal of the corresponding differential amplifier 40. The switch element T1 is a single-pole single-throw switch provided in the middle of this wiring L1. When the switch element T1 is on, one end of the loop coil LCx is connected to the non-inverting input terminal of the differential amplifier 40, while when the switch element T1 is off, one end of the loop coil LCx is disconnected from the non-inverting input terminal of the differential amplifier 40.

[0096] The wiring L2 is a wiring that connects the other end of the loop coil LCx to the inverting input terminal of the corresponding differential amplifier 40. The switch element T2 is a single-pole single-throw switch provided in the middle of this wiring L2. When the switch element T2 is on, the other end of the loop coil LCx is connected to the inverting input terminal of the differential amplifier 40, while when the switch element T2 is off, the other end of the loop coil LCx is disconnected from the inverting input terminal of the differential amplifier 40.

[0097] The switch element S1 is a single-pole single-throw switch provided between a power supply wiring to which a predetermined power supply potential Vref (for example, a ground potential or an intermediate potential of a pen signal) is supplied and a portion of the wiring L1 between the switch element T1 and the loop coil LCx, and serves to supply the power supply potential Vref to one end of the loop coil LCx. Similarly, the switch element S2 is a single-pole single-throw switch provided between a power supply wiring to which a predetermined power supply potential Vref is supplied and a portion of the wiring L2 between the switch element T2 and the loop coil LCx, and serves to supply the power supply potential Vref to the other end of the loop coil LCx.

[0098] The control of the switch elements S1 and S2 is executed by a precharge signal pre generated by the sensor controller 31. Also, the control of the switch elements T1 and T2 is executed by a selection signal sel generated by the sensor controller 31. Hereinafter, the control of the switch elements S1, S2, T1, and T2 performed by the sensor controller 31 using these signals will be described in detail.

[0099] FIG. 14 is a diagram showing waveforms of signals related to the control of the switch elements S1, S2, T1, and T2. The voltage PE shown in the figure is the voltage across the coil constituting the resonance circuit of the electromagnetic induction pen 2. When the sensor controller 31 starts sending an alternating magnetic field from the loop coil LCy at time t1, the voltage PE rises as shown in the figure in the electromagnetic induction pen 2 located in the vicinity thereof. The sensor controller 31 continues to send this alternating magnetic field from time t1 to time t3, which is a predetermined time Ta later.

[0100] While continuously transmitting the alternating magnetic field, at time t2 (the time after a predetermined time Tb (< Ta) from time t1), the sensor controller 31 activates the precharge signal pre. As a result, the switch elements S1 and S2 shown in FIG. 13 turn on, and the supply of the power supply potential Vref to the loop coil LCx is started. The sensor controller 31 maintains the precharge signal pre in the active state until time t3 or immediately before that time, and then returns the precharge signal pre to the inactive state. By performing this series of processes, each loop coil LCx can be precharged, so that the influence of the alternating magnetic field transmitted from the loop coil LCy can be eliminated from the loop coil LCx, and it becomes possible to improve the SNR of the pen signal PS.

[0101] Here, as shown in FIG. 13, the switch circuit 30 is configured such that the power supply potential Vref is supplied to each of one end and the other end of the loop coil LCx in order to complete the precharge in a shorter time. That is, as described above, since the loop coil LCx has a time constant, when the power supply potential Vref is supplied to the loop coil LCx, the whole does not immediately become the power supply potential Vref. Instead, it gradually transitions to the power supply potential Vref over a certain period of time starting from the portion close to the power supply wiring. Therefore, if the power supply potential Vref is supplied to both one end and the other end of the loop coil LCx, this time can be shortened. However, the configuration of supplying the power supply potential Vref to both one end and the other end of the loop coil LCx is not essential, and it may be sufficient to supply the power supply potential Vref to only one of them.

[0102] Returning to FIG. 14, the sensor controller 31 that stops transmitting the alternating magnetic field at time t3 activates the selection signal sel simultaneously with the stop of transmission, turning on the switch elements T1 and T2. Then, the alternating magnetic field transmitted from the electromagnetic induction pen 2 generates an alternating current in the loop coil LCx, and as shown, this is supplied to the sensor controller 31 as the pen signal PS. As a result, the sensor controller 31 can acquire the pen position and pen data based on the pen signal PS. The sensor controller 31 maintains the selection signal sel in the active state until time t4 when it starts transmitting the alternating magnetic field again, and then returns the selection signal sel to the inactive state. The subsequent processing is a repetition of the processing described so far.

[0103] As described above, according to the switch circuit 30 and the sensor controller 31 according to the present embodiment, each loop coil LCx can be pre-charged by turning on the switch elements S1 and S2. Therefore, the influence of the alternating magnetic field transmitted from the loop coil LCy on the transmission side can be excluded from each loop coil LCx on the reception side, and the SNR of the pen signal PS can be improved.

[0104] FIG. 15 is a diagram showing a method of driving an EMR sensor according to a modification of the present embodiment. The sensor controller 31 according to this modification is different from the sensor controller 31 according to the present embodiment in that when performing the global scan described above, each time an alternating current is passed through each loop coil LCy, the pen signal is received not by all of the plurality of loop coils LCx but only by half of them. Hereinafter, the differences will be described with attention paid to them. Note that FIG. 15 shows only six loop coils LCx and LCy each for simplicity of explanation, but the same applies when the EMR sensor includes more loop coils LCx and LCy.

[0105] FIG. 15(a) shows the first reception mode of the pen signal, and FIG. 15(b) shows the second reception mode of the pen signal. The sensor controller 31 according to this modification detects the pen position by alternately performing the first reception mode and the second reception mode.

[0106] As a premise, the switch circuit 30 according to this modification example is configured such that, among a plurality of loop coils LCx, the (2n - 1)-th (n is a natural number; odd-numbered) loop coil LCx from one end side in the x direction and the 2n-th (even-numbered) loop coil LCx from one end side in the x direction are controlled by different selection signals sel to control the switching elements T1 and T2. As a result, in the switch circuit 30 according to this modification example, one end and the other end of the (2n - 1)-th (odd-numbered) loop coil LCx from one end side in the x direction among the plurality of loop coils LCx are connected to the non-inverting input terminal and the inverting input terminal of the corresponding differential amplifier 40, while one end and the other end of the 2n-th (even-numbered) loop coil LCx are disconnected from the non-inverting input terminal and the inverting input terminal of the corresponding differential amplifier 40 in a first state, and one end and the other end of the 2n-th (even-numbered) loop coil LCx from one end side in the x direction among the plurality of loop coils LCx are connected to the non-inverting input terminal and the inverting input terminal of the corresponding differential amplifier 40, while one end and the other end of the (2n - 1)-th (odd-numbered) loop coil LCx are disconnected from the non-inverting input terminal and the inverting input terminal of the corresponding differential amplifier 40 in a second state, and the switch circuit 30 is configured to be switchable according to the control from the sensor controller 31.

[0107] In the first reception mode shown in FIG. 15(a), when the sensor controller 31 passes an alternating current through the (2m - 1)-th (m is a natural number; odd-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, and when the sensor controller 31 passes an alternating current through the 2m-th (even-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, thereby receiving the pen signals output from each of the plurality of differential amplifiers 40. According to this process, detection of the pen position is performed centering on the portion hatched in FIG. 15(a).

[0108] On the other hand, in the second reception mode shown in Fig. 15(b), when the sensor controller 31 passes an alternating current through the (2m - 1)-th (odd-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, and when passing an alternating current through the 2m-th (even-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, thereby receiving the pen signals output from each of the plurality of differential amplifiers 40. According to this process, detection of the pen position is performed centering on the portion hatched in Fig. 15(b). Comparing with Fig. 15(a), it is understood that hatching is applied to the portion where there was no hatching in Fig. 15(a).

[0109] According to this modification, for example, in the first reception mode, the switch circuit 30 is always set to the first state regardless of which loop coil LCy the alternating current is passed through, and in the second reception mode, the switch circuit 30 is always set to the second state regardless of which loop coil LCy the alternating current is passed through. Compared with this case, it becomes possible to detect the pen position more accurately. As can be understood from Figs. 15(a) and 15(b), hatched portions (i.e., portions where the intensity of the pen signal is obtained) are arranged above, below, left, and right of the non-hatched portion (i.e., the portion where the intensity of the pen signal is not obtained) (i.e., arranged in a grid pattern). This is the effect that the intensity distribution of the pen signal can be accurately derived in all directions.

[0110] Also, according to this modification, since the number of differential amplifiers 40 used simultaneously is half that of the present embodiment, it is also possible to halve the number of differential amplifiers 40 prepared in the switch circuit 30. Also, for the same reason, it is possible to halve the number of circuits arranged in the sensor controller 31 for receiving the pen signal.

[0111] FIG. 16 is a diagram showing the configuration of the position detection system 1 according to the fourth embodiment of the present invention. The position detection system 1 according to the present embodiment is different from the position detection system 1 according to the third embodiment in that a comb-shaped coil CCx including a base PB and a plurality of comb teeth PT is used as the receiving side coil of the EMR sensor instead of a plurality of loop coils LCx. Along with this, the internal configuration of the switch circuit 30 and the content of the control of the switch circuit 30 by the sensor controller 31 are also different from those of the position detection system 1 according to the third embodiment. Since other points are the same as those of the position detection system 1 according to the third embodiment, the following description will focus on the differences from the position detection system 1 according to the third embodiment.

[0112] As shown in FIG. 16, the comb-shaped coil CCx is a coil configured by connecting a plurality of comb teeth PT, which are wirings extending in the y direction, to a base PB, which is a single wiring extending in the x direction. One end of each comb tooth PT is connected to the base PB, and the other end is connected to the switch circuit 30.

[0113] FIGS. 17 and 18 are diagrams showing the internal configuration of the switch circuit 30 according to the present embodiment. These figures show only the part related to the reception of the pen signal in a part of the comb teeth PT among the internal configuration of the switch circuit 30. In the following description, the x-th comb tooth PT from the one end side in the x direction among the plurality of comb teeth PT is referred to as the comb tooth PT x to distinguish it from other comb teeth PT.

[0114] As shown in FIGS. 17 and 18, the switch circuit 30 according to the present embodiment includes a plurality of differential amplifiers 50 and a plurality of switches 51, 52. The differential amplifiers 50 are provided at a ratio of one for two comb teeth PT, and the switches 51, 52 are provided for each comb tooth PT. The configuration and operation of each differential amplifier 50 are the same as those of the differential amplifier 40 described in the third embodiment. In the following description, among the plurality of differential amplifiers 50, the one provided corresponding to the comb tooth PT x-1 , PT x is referred to as the differential amplifier 50 xIt may be referred to as such to distinguish it from other differential amplifiers 50.

[0115] The switch 51 is a single-pole triple-throw switch. The common terminal of the switch 51 is connected to the other end of the corresponding comb tooth portion PT. When the common terminal is connected to the comb tooth portion PT x-1 The first selection terminal of the switch 51 connected to the comb tooth portion PT is connected to the non-inverting input terminal of the differential amplifier 50 x-2 The second selection terminal is connected to the open end, and the third selection terminal is connected to the inverting input terminal of the differential amplifier 50 x When the common terminal is connected to the comb tooth portion PT x The first selection terminal of the switch 51 connected to the comb tooth portion PT is connected to the inverting input terminal of the differential amplifier 50 x The second selection terminal is connected to the open end, and the third selection terminal is connected to the non-inverting input terminal of the differential amplifier 50 x is connected.

[0116] The switch 52 is a single-pole single-throw switch provided between a power supply wiring to which a predetermined power supply potential Vref (for example, ground potential) is supplied and a wiring connecting the common terminal of the corresponding switch 51 to the comb tooth portion PT, and serves to supply the power supply potential Vref to the corresponding comb tooth portion PT.

[0117] The control of the switches 51 and 52 is executed by the sensor controller 31. Among these, the control of the switch 52 is performed to pre-charge the comb tooth portion PT, and is executed at the same timing as the control of the switches S1 and S2 described with reference to FIG. 14. Also, regarding the timing of connecting the common terminal to the second selection terminal (open end) in the control of the switch 51, it is executed at the same timing as the timing of turning off the switches T1 and T2 described with reference to FIG. 14. As a result, each differential amplifier 50 is connected to the comb tooth portion PT only during the period when the transmission of the alternating magnetic field from the loop coil LCy is stopped.

[0118] Regarding the control of switch 51, for the timing of connecting the common terminal to the first selection terminal or the third selection terminal, the sensor controller 31 controls so that the interval of the virtual loop coils formed in the comb-shaped coil CCx becomes effectively zero in order to detect the pen position with high accuracy even when the comb-shaped coil CCx is used as the receiving-side coil of the EMR sensor. Hereinafter, this point will be specifically described.

[0119] First, the state of the switch circuit 30 will be described. The switch circuit 30 is configured to be switchable between a first state (the state shown in FIG. 17) in which the third selection terminal is selected in each switch 51 and a second state (the state shown in FIG. 18) in which the first selection terminal is selected in each switch 51 under the control of the sensor controller 31. In the first state, as shown in FIG. 17, the other ends of the (2n - 1)-th (n is a natural number; odd-numbered) comb tooth part PT and the 2n-th (even-numbered) comb tooth part PT among the plurality of comb tooth parts PT from one end side in the x direction are respectively connected to the inverting input terminal and the non-inverting input terminal of the same differential amplifier 50. As a result, a virtual loop coil is formed by the (2n - 1)-th comb tooth part PT, the 2n-th comb tooth part PT, and the part of the base PB connecting these (the part marked with a circle in FIG. 17). On the other hand, in the second state, as shown in FIG. 18, the other ends of the 2n-th (even-numbered) comb tooth part PT and the (2n + 1)-th (odd-numbered) comb tooth part PT among the plurality of comb tooth parts PT from one end side in the x direction are respectively connected to the inverting input terminal and the non-inverting input terminal of the same differential amplifier 50. As a result, a virtual loop coil is formed by the 2n-th comb tooth part PT, the (2n + 1)-th comb tooth part PT, and the part of the base PB connecting these (the part marked with a circle in FIG. 18).

[0120] For each loop coil LCy, the sensor controller 31 starts the supply of an alternating current to the loop coil LCy, stops the supply, then switches the switch circuit 30 to the first state to receive a pen signal, further starts the supply of an alternating current to the same loop coil LCy again, stops the supply, and then switches the switch circuit 30 to the second state to receive a pen signal. This process is a process common to global scanning and local scanning. Thereby, in both global scanning and local scanning, the interval between virtual loop coils constituted by the comb-shaped coils CCx can be effectively set to zero, so that it becomes possible to improve the detection accuracy of the pen position when the comb-shaped coil CCx is used as the receiving coil of the EMR sensor.

[0121] As described above, according to the switch circuit 30 and the sensor controller 31 according to the present embodiment, the reception of the pen signal in the first state and the reception of the pen signal in the second state can be executed in a time-division manner. Therefore, the interval between virtual loop coils can be effectively set to zero, so that it becomes possible to improve the detection accuracy of the pen position when the comb-shaped coil CCx is used as the receiving coil of the EMR sensor.

[0122] Further, according to the switch circuit 30 and the sensor controller 31 according to the present embodiment, since each comb tooth portion PT can be pre-charged by turning on the switch 52, as in the third embodiment, the influence of the alternating magnetic field sent from the transmitting-side loop coil LCy can be excluded from each comb tooth portion PT on the receiving side, and it becomes possible to improve the SNR of the pen signal PS.

[0123] FIG. 19 is a diagram showing a method for driving an EMR sensor according to a modified example of the present embodiment. The sensor controller 31 according to this modified example is different from the sensor controller 31 according to the present embodiment in that, when performing a single global scan, for each loop coil LCy, only one of the reception of the pen signal using the switch circuit 30 in the first state and the reception of the pen signal using the switch circuit 30 in the second state is performed, rather than both. Hereinafter, the differences will be described with attention paid to them. Note that, for the sake of simplicity of explanation, FIG. 19 shows only six loop coils LCy and seven comb teeth portions PT, but the same applies to the case where the EMR sensor includes more loop coils LCy and comb teeth portions PT.

[0124] FIG. 19(a) shows the first reception mode of the pen signal, and FIG. 19(b) shows the second reception mode of the pen signal. The sensor controller 31 according to this modified example detects the pen position by alternately performing a global scan in the first reception mode and a global scan in the second reception mode.

[0125] In the first reception mode, when the sensor controller 31 passes an alternating current through the (2m - 1)-th loop coil LCy (m is a natural number, an odd number) from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, and when passing an alternating current through the 2m-th loop coil LCy (an even number) from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, thereby receiving the pen signals output from the respective differential amplifiers 50. According to this process, the detection of the pen position is executed centering on the portion hatched in FIG. 19(a).

[0126] On the other hand, in the second reception mode, when the sensor controller 31 passes an alternating current through the (2m - 1)-th (odd-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, and when passing an alternating current through the 2m-th (even-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, thereby receiving the pen signals output from each of the plurality of differential amplifiers 50. According to this process, the detection of the pen position is executed centering on the portion hatched in FIG. 19(b). Comparing with FIG. 19(a), it is understood that hatching is applied to the portion that was not hatched in FIG. 19(a).

[0127] According to this modification, compared with the present embodiment, it is possible to complete one global scan in half the time. Although the accuracy of the pen position detected in one global scan is lower than that of the present embodiment, since the hatched portions in each global scan are arranged in a lattice pattern similar to the modification of the third embodiment described with reference to FIG. 15, for example, in the first reception mode, the switch circuit 30 is set to the first state whenever an alternating current is passed through any loop coil LCy, and in the second reception mode, compared with the case where the switch circuit 30 is set to the second state whenever an alternating current is passed through any loop coil LCy, it becomes possible to accurately detect the pen position.

[0128] FIG. 20 is a diagram showing the configuration of the position detection system 1 according to the fifth embodiment of the present invention. The position detection system 1 according to the present embodiment is different from the position detection system 1 according to the fourth embodiment in that, as the reception-side coil of the EMR sensor, a plurality of linear electrodes LE extending in the y direction and arranged side by side in the x direction are used instead of the comb-shaped coil CCx. Since the other points are the same as those of the position detection system 1 according to the fourth embodiment, the description will be made below focusing on the differences from the position detection system 1 according to the fourth embodiment.

[0129] The configuration of the EMR sensor according to this embodiment is, in short, a configuration in which the base PB is removed from the comb-shaped coil CCx of the fourth embodiment. FIGS. 21 and 22 are diagrams showing the internal configuration of the switch circuit 30 according to this embodiment. As can be understood by comparing these figures with FIGS. 17 and 18, the configuration within the switch circuit 30 is the same as that within the switch circuit 30 according to the fourth embodiment, except that the connection destination is the linear electrode LE instead of the comb teeth portion PT. Therefore, the switch circuit 30 according to this embodiment is also configured to be able to switch between the first state and the second state described in the fourth embodiment under the control of the sensor controller 31. FIG. 21 shows the first state, and FIG. 22 shows the second state. The reception process of the pen signal performed by the sensor controller 31 using this control may be the same as that in the fourth embodiment.

[0130] In this embodiment, since each linear electrode LE is electrically isolated, a virtual loop coil as described in the fourth embodiment is not formed when the switch circuit 30 is in either the first state or the second state. Compared with the loop coil LCx described in the third embodiment and the comb-shaped coil CCx described in the fourth embodiment, the coupling between the linear electrode LE and the coil in the electromagnetic induction pen 2 is weak, so the reception intensity of the pen signal received by each individual linear electrode LE is weaker than that in the third embodiment and the fourth embodiment. However, according to the configuration of the switch circuit 30 according to this embodiment, an effect that the reception intensity of the pen signal is increased is obtained, particularly in the vicinity of the pen position. This is due to the fact that the signs of the pen signals are reversed between the linear electrode LE on one side in the x direction and the linear electrode LE on the other side when viewed from the pen position. Hereinafter, this point will be described with reference to a graph of the reception intensity.

[0131] FIG. 23 is a diagram showing the simulation results of the reception intensity of the pen signal. The graph G1 shown in the figure shows the simulation results of the reception intensity of the pen signal received by the sensor controller 31 according to the present embodiment. On the other hand, the graph G0 shows the simulation results of the reception intensity of the pen signal received by the sensor controller 31 when using a position detection device of a type that supplies the pen signal received by each linear electrode LE to the sensor controller 31 alone without using the differential amplifier 50. The horizontal axis in the figure indicates the serial number of the linear electrode LE. The position on the horizontal axis of each point of the graph G1 corresponds to the intermediate position in the x direction of the two linear electrodes LE connected to the same differential amplifier 50. This also applies to the graph G2 described later.

[0132] FIG. 23 shows an example in which the pen tip of the electromagnetic induction pen 2 is between the 10th linear electrode LE and the 11th linear electrode LE. First, focusing on the graph G0, it can be understood that the signs of the reception intensities of the pen signals received by the linear electrodes LE up to the 10th and the reception intensities of the pen signals received by the linear electrodes LE up to the 11th are opposite, and in the vicinity of the pen position, the reception intensity of the pen signal becomes almost zero.

[0133] Next, focusing on the graph G1, it can be understood that a normal distribution-like distribution having a peak at the pen position can be obtained. Such a distribution is obtained because the pen signals with opposite signs are strengthened by the differential amplifier 50. From this result, it can be understood that according to the position detection device 3 of the present embodiment, the effect that the reception intensity of the pen signal increases in the vicinity of the pen position can be obtained.

[0134] As described above, according to the position detection device 3 of the present embodiment, the pen signals having opposite signs are strengthened by the differential amplifier 50, so that in the vicinity of the pen position, it is possible to increase the reception intensity of the pen signal when the linear electrode LE is used as the Rx coil.

[0135] Figs. 24 and 25 are diagrams showing the internal configuration of the switch circuit 30 according to the first modification of the present embodiment. Fig. 24 shows the first state, and Fig. 25 shows the second state. As can be understood by comparing Figs. 24 and 25 with Figs. 21 and 22, the switch circuit 30 according to this modification is different from the switch circuit 30 according to the present embodiment in that the two linear electrodes LE connected to the same differential amplifier 50 are not two that are directly adjacent, but two that are adjacent with two linear electrodes LE sandwiched therebetween. In other respects, it is the same as the switch circuit 30 according to the present embodiment, and the content of the control of the switch circuit 30 by the sensor controller 31 is also the same as that according to the present embodiment. x The switch circuit 30 according to this modification is different from the switch circuit 30 according to the present embodiment in that, among the plurality of linear electrodes LE, instead of two that are directly adjacent, two are adjacent with two linear electrodes LE sandwiched therebetween. In other respects, it is the same as the switch circuit 30 according to the present embodiment, and the content of the control of the switch circuit 30 by the sensor controller 31 is also the same as that according to the present embodiment.

[0136] The switch circuit 30 according to this modification is configured to be switchable between a first state in which the ends of the (2n - k)-th (k = 3, n is a natural number greater than k / 2) linear electrode LE and the 2n-th linear electrode LE from one end side in the x direction among the plurality of linear electrodes LE are respectively connected to the inverting input terminal and the non-inverting input terminal of the same differential amplifier 50, and a second state in which the ends of the 2n-th linear electrode LE and the (2n + k)-th linear electrode LE from one end side in the x direction among the plurality of linear electrodes LE are respectively connected to the inverting input terminal and the non-inverting input terminal of the same differential amplifier 50. In this modification, k = 3, but if k = 1, the switch circuit 30 described in the present embodiment is obtained. Generally speaking, k may be an odd natural number, and a value of k that maximizes the reception intensity of the pen signal in the vicinity of the pen position may be selected.

[0137] Graph G2 shown in Fig. 23 shows the simulation result of the reception intensity of the pen signal received by the sensor controller 31 according to this modification. As can be understood by comparing with Graph G1, according to the switch circuit 30 of this modification, a normal distribution-like shape having a peak at the pen position is obtained, similar to Graph G1, and moreover, the reception intensity of the peak is greater than that of Graph G1. Therefore, it can be said that according to the position detection device 3 according to this modification, it is possible to further increase the reception intensity of the pen signal when the linear electrode LE is used as the Rx coil in the vicinity of the pen position.

[0138] FIG. 26 is a diagram showing a method of driving an EMR sensor according to a second modification of the present embodiment. The sensor controller 31 according to this modification is different from the sensor controller 31 according to the present embodiment in that, when performing a single global scan, for each loop coil LCy, only one of the reception of the pen signal using the switch circuit 30 in the first state and the reception of the pen signal using the switch circuit 30 in the second state is performed, rather than both. Hereinafter, the description will be made focusing on the differences. Note that, for simplicity of explanation, FIG. 26 shows only six loop coils LCy and seven linear electrodes LE, but the same applies when the EMR sensor includes more loop coils LCy and linear electrodes LE.

[0139] FIG. 26(a) shows a first reception mode of the pen signal, and FIG. 26(b) shows a second reception mode of the pen signal. The sensor controller 31 according to this modification detects the pen position by alternately performing a global scan in the first reception mode and a global scan in the second reception mode.

[0140] In the first reception mode, when the sensor controller 31 passes an alternating current through the (2m - 1)-th loop coil LCy (m is a natural number, an odd number) from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, and when passing an alternating current through the 2m-th loop coil LCy (an even number) from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, thereby receiving the pen signals output from the respective differential amplifiers 50. According to this process, the detection of the pen position is executed centering on the portion hatched in FIG. 26(a).

[0141] On the other hand, in the second reception mode, when the sensor controller 31 passes an alternating current through the (2m - 1)-th (odd-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the second state, and when passing an alternating current through the 2m-th (even-numbered) loop coil LCy from one end side in the y direction among the plurality of loop coils LCy, the switch circuit 30 is set to the first state, thereby receiving the pen signals output from each of the plurality of differential amplifiers 50. According to this process, detection of the pen position is performed centering on the portion hatched in Fig. 26(b). Comparing with Fig. 26(a), it is understood that hatching is applied to the portion that was not hatched in Fig. 26(a).

[0142] According to this modification example, compared with the present embodiment, it becomes possible to complete one global scan in half the time. Although the accuracy of the pen position detected in one global scan is lower than that of the present embodiment, since the hatched portions in each global scan are arranged in a grid pattern similar to the modification example of the third embodiment described with reference to Fig. 15, for example, in the first reception mode, the switch circuit 30 is set to the first state whenever an alternating current is passed through any loop coil LCy, and in the second reception mode, compared with the case where the switch circuit 30 is set to the second state whenever an alternating current is passed through any loop coil LCy, it becomes possible to detect the pen position with high accuracy.

[0143] Next, the position detection system 1 according to the sixth embodiment of the present invention will be described. The position detection system 1 according to the present embodiment is different from the third embodiment in terms of the internal processing of the sensor controller 31. Since it is the same as the position detection system 1 according to the third embodiment in other aspects, the following description will focus on the differences from the position detection system 1 according to the third embodiment.

[0144] FIG. 27 is a diagram showing problems in the case of receiving a pen signal using the position detection system 1 according to the third embodiment. Further, FIG. 28 is a diagram for explaining the azimuth angle θ and the tilt angle φ used in FIG. 27. Hereinafter, before explaining the position detection system 1 according to the present embodiment, the problems solved by the position detection system 1 according to the present embodiment will be explained with reference to these figures.

[0145] As shown in FIG. 28, for the electromagnetic induction pen 2, three angles, namely, the azimuth angle θ, the tilt angle φ, and the rotation angle ψ are defined. The azimuth angle θ is an angle representing the direction indicated by the pen tip of the electromagnetic induction pen 2 in contact with the touch surface 3a, and is represented by the angle formed by a predetermined axis set in the touch surface 3a and the projection of the pen axis of the electromagnetic induction pen 2 onto the touch surface 3a. The tilt angle φ is an angle indicating the inclination of the electromagnetic induction pen 2 with respect to the touch surface 3a, and is represented by the angle formed by the pen axis of the electromagnetic induction pen 2 and the touch surface 3a. The rotation angle ψ is an angle indicating the amount of rotation of the electromagnetic induction pen 2 around its own pen axis. The problems solved by the position detection system 1 according to the present embodiment relate to the azimuth angle θ and the tilt angle φ among these angles.

[0146] FIG. 27 shows the reception levels of the pen signal PS received in the loop coil LCx corresponding to each x coordinate when the pen tip of the electromagnetic induction pen 2 is at the position of x coordinate = 0 mm and the azimuth angle θ and the tilt angle φ are (θ, φ) = (0°, 0°), (0°, 60°), (180°, 60°), and (90°, 60°), respectively. As shown in the figure, when (θ, φ) = (0°, 0°) or (90°, 60°), the peak of the reception level of the pen signal PS is at the position of x coordinate = 0 mm. On the other hand, when (θ, φ) = (0°, 60°), the peak position of the reception level of the pen signal PS is shifted to the negative side. Also, when (θ, φ) = (180°, 60°), the peak position of the reception level of the pen signal PS is shifted to the positive side. Thus, in the position detection system 1 according to the third embodiment, depending on the combination of the azimuth angle θ and the tilt angle φ of the electromagnetic induction pen 2, the peak position of the reception level of the pen signal PS may deviate from the position of the original pen tip. The position detection system 1 according to the present embodiment attempts to improve the deterioration of the detection accuracy of the pen position caused by such a deviation.

[0147] FIG. 29(a) is a diagram for explaining the processing performed by the sensor controller 31 according to the present embodiment. As shown in the figure, the sensor controller 31 according to the present embodiment adds the pen signal PS received in the n-th loop coil LCx n and the pen signals PS received in one or more loop coils LCx in the vicinity of the loop coil LCx n with different weightings, and is configured to derive the position of the electromagnetic induction pen 2 using the added pen signal PS n obtained by the addition. SUM Specifically, the sensor controller 31 according to the present embodiment adds the pen signals PS

[0148] received in five loop coils LCx from the (n - 2)-th loop coil LCx n-2 to the (n + 2)-th loop coil LCx n+2 with different weightings, and is configured to derive the position of the electromagnetic induction pen 2 using the added pen signal PS n-2 ~PS n+2is the pen signal PS received in three loop coils LCx located at the center of the five loop coils LCx n-1 ~PS n+1 is weighted more than the pen signal received in the other two loop coils LCx n-2 ,PS n+2 by twice as much, and the above addition is performed. As a result, as shown in the figure, PS SUM =PS n-2 +2·PS n-1 +2·PS n +2·PS n+1 +PS n+2 is obtained.

[0149] Figure 29(b) is a diagram showing a virtual loop coil VLCx obtained by the addition shown in Figure 29(a). As shown in the figure, the added pen signal PS obtained by performing the addition shown in Figure 29(a) SUM is a signal equivalent to the pen signal PS received by a double-wound coil in which the width of the inner wiring is X1 (the width of three loop coils LCx) and the distance between the outer wiring and the inner wiring is X2 (the width of one loop coil LCx).

[0150] Figure 30 is a diagram showing the reception level of the added pen signal PS SUM when the pen tip of the electromagnetic induction pen 2 is at the position of x coordinate = 0 mm. In the figure, as in Figure 27, when the azimuth angle θ and the tilt angle φ are (θ, φ) = (0°, 0°), (0°, 60°), (180°, 60°), and (90°, 60°), respectively, the added pen signal PS SUM (the signal obtained by weighted addition of the pen signal PS received by the five loop coils LCx centered on that loop coil LCx) is shown.

[0151] As shown in Figure 30, the peak position of the reception level of the added pen signal PS SUM is at the position of x coordinate = 0 mm regardless of the azimuth angle θ and the tilt angle φ of the electromagnetic induction pen 2. When (θ, φ) = (90°, 60°), at the position of x coordinate = 0 mm, the added pen signal PS SUMAlthough the reception level of is slightly depressed, since it has a symmetric shape, the detection accuracy of the pen position is not deteriorated by this depression. Therefore, according to the position detection system 1 according to the present embodiment, even if the electromagnetic induction pen 2 is tilted with respect to the touch surface 3a, it can be said that its position can be detected with high accuracy.

[0152] As described above, according to the position detection system 1 according to the present embodiment, the addition pen signal PS is obtained by adding the pen signals PS received by the plurality of loop coils LCx with different weightings. SUM Since the position of the electromagnetic induction pen 2 is derived using , even if the electromagnetic induction pen 2 is tilted with respect to the touch surface 3a, its position can be detected with high accuracy.

[0153] Next, the position detection system 1 according to the seventh embodiment of the present invention will be described. The position detection system 1 according to the present embodiment is different from the fourth embodiment in that the position detection device 3 is a smartphone with a foldable display, the internal configuration of the switch circuit 30, and the internal processing of the sensor controller 31. Since it is the same as the position detection system 1 according to the fourth embodiment in other points, the following description will focus on the differences from the position detection system 1 according to the fourth embodiment.

[0154] Here, in the following description, the method for detecting the position of the electromagnetic induction pen 2 realized by the switch circuit 30 and the sensor controller 31 according to the fourth embodiment may be referred to as the "ODD / EVEN method". "ODD" and "EVEN" respectively correspond to the first state and the second state of the switch circuit 30 described in the fourth embodiment. Further, the method for detecting the position of the electromagnetic induction pen 2 realized by the switch circuit 30 and the sensor controller 31 according to the present embodiment may be referred to as the "A / B / C method". Although details will be described later, the switch circuit 30 according to the present embodiment is configured to be able to switch between three states from the first state to the third state, and "A", "B", and "C" respectively correspond to the first state to the third state.

[0155] FIG. 31(a) is a plan view of the EMR sensor 33 included in the position detection device 3 according to the present embodiment, and FIG. 31(b) is a cross-sectional view of the EMR sensor 33 corresponding to the line A-A shown in FIG. 31(a). As shown in these figures, the EMR sensor 33 includes a substrate 34 on which a receiving coil and a transmitting coil are formed, and a magnetic sheet 35 made of a magnetic material. The magnetic sheet 35 is a member that functions as a magnetic path of the magnetic field generated by the coil in the substrate 34, and is arranged so as to cover the entire one surface of the substrate 34 (the surface opposite to the touch surface 3a).

[0156] When the display (not shown) included in the position detection device 3 is a foldable display, of course, the EMR sensor 33 also needs to be configured to be foldable. The illustrated component 36 is a conductive hinge component required for this purpose, and is arranged between the substrate 34 and the magnetic sheet 35 along the folding line FL.

[0157] FIG. 32(a) is a diagram collectively showing the distribution of the reception levels of the pen signals PS received when the pen tip of the electromagnetic induction pen 2 is at each position in the x direction, assuming that the ODD / EVEN method is adopted in the position detection device 3 according to the present embodiment. As shown in the figure, according to the ODD / EVEN method, the reception level of the pen signal PS significantly decreases in the vicinity of the folding line FL. This is due to the magnetic field being disturbed by the hinge component 36 shown in FIGS. 31(a) and 31(b). At the reception level as shown in FIG. 32(a), it is difficult to derive the pen position in the vicinity of the folding line FL, and an improvement in the reception level of the pen signal PS in the vicinity of the folding line FL has been required. The position detection system 1 according to the present embodiment attempts to achieve such an improvement in the reception level of the pen signal PS by using the A / B / C method instead of the ODD / EVEN method.

[0158] Figs. 33 to 35 are diagrams showing the internal configuration of the switch circuit 30 according to the present embodiment. These figures show only the parts related to the reception of the pen signals in some of the comb teeth portions PT among the internal configuration of the switch circuit 30, similar to Figs. 17 and 18. In the following description, the x-th comb tooth portion PT from one end side in the x direction among the plurality of comb tooth portions PT is referred to as the comb tooth portion PT x and may be distinguished from other comb tooth portions PT.

[0159] As shown in Figs. 33 to 35, the switch circuit 30 according to the present embodiment has a differential amplifier 50 at a ratio of one for every three comb tooth portions PT. In the following description, among the plurality of differential amplifiers 50, the one provided corresponding to the comb tooth portion PT x-1 , PT x , PT x+1 is referred to as the differential amplifier 50 x and may be distinguished from other differential amplifiers 50.

[0160] The common terminal of the switch 51 according to the present embodiment is connected to the other end of the corresponding comb tooth portion PT. The first selection terminal of the switch 51 whose common terminal is connected to the comb tooth portion PT x is connected to the inverting input terminal of the differential amplifier 50 x , the second selection terminal is connected to the open end, and the third selection terminal is connected to the non-inverting input terminal of the differential amplifier 50 x . The first selection terminal of the switch 51 whose common terminal is connected to the comb tooth portion PT x-1 is connected to the inverting input terminal of the differential amplifier 50 x , the second selection terminal is connected to the open end, and the third selection terminal is connected to the non-inverting input terminal of the differential amplifier 50 x-2 . The first selection terminal of the switch 51 whose common terminal is connected to the comb tooth portion PT x+1 is connected to the inverting input terminal of the differential amplifier 50 x+2 , the second selection terminal is connected to the open end, and the third selection terminal is connected to the non-inverting input terminal of the differential amplifier 50 x . Summarizing the above configuration from the differential amplifier 50 x side, the inverting input terminal of the differential amplifier 50 x is connected to the comb tooth portions PT x-2 , PTx-1 , PT x The first selection terminals of each of the three switches 51 corresponding to x are commonly connected, and the differential amplifier 50 x to the non-inverting input terminal of, the comb teeth part PT x , PT x+1 , PT x+2 The third selection terminals of each of the three switches 51 corresponding to x+2 will be commonly connected.

[0161] The switch circuit 30 according to the present embodiment, for each differential amplifier 50, selects two out of the corresponding five comb teeth parts PT (if it is the differential amplifier 50 x , the comb teeth part PT x-2 , PT x-1 , PT x , PT x+1 , PT x+2 of the five) according to the control of the sensor controller 31, and functions as a selection circuit that connects the selected two comb teeth parts PT to the differential amplifier 50 as a reception circuit.

[0162] The sensor controller 31 according to the present embodiment, for example, regarding the differential amplifier 50 x is described as follows. It controls the switch circuit 30 so that the first state of selecting the comb teeth part PT x-2 , PT x , the second state of selecting the comb teeth part PT x-1 , PT x+1 , and the third state of selecting the comb teeth part PT x , PT x+2 appear in order. That is, the sensor controller 31 according to the present embodiment plays a role in realizing the above-described A / B / C method. After controlling a plurality of switches 51 so that the third state appears, the sensor controller 31 repeats the same control from the first state. The same applies to other differential amplifiers 50. The sensor controller 31 controls the switch circuit 30 so that the states of the respective switches 51 corresponding to the differential amplifier 50 x and the states of the respective switches 51 corresponding to other differential amplifiers 50 are synchronized with each other and become the same state.

[0163] Figures 33 to 35 respectively show the case where the switch circuit 30 is in the first state, the second state, and the third state. In the first state shown in Figure 33, the differential amplifier 50 x has the comb teeth portions PT x-2 , PT x connected to each input terminal thereof, and one virtual loop coil is formed by these comb teeth portions PT x-2 , PT x and the portion of the base PB that connects them. The same applies to the other differential amplifiers 50. Similarly, in the second state shown in Figure 34, the differential amplifier 50 x has the comb teeth portions PT x-1 , PT x+1 connected to each input terminal thereof, and one virtual loop coil is formed by these comb teeth portions PT x-1 , PT x+1 and the portion of the base PB that connects them. Also, in the third state shown in Figure 35, the differential amplifier 50 x has the comb teeth portions PT x , PT x+2 connected to each input terminal thereof, and one virtual loop coil is formed by these comb teeth portions PT x , PT x+2 and the portion of the base PB that connects them.

[0164] As can be understood from these, according to the A / B / C method, the virtual loop coil will shift in the x direction at a distance (the second distance) shorter than the distance (the first distance) between the two comb teeth portions PT that constitute the virtual loop coil. The first distance is the distance between two adjacent comb teeth portions PT with one comb teeth portion PT in between, and the second distance is the distance between two adjacent comb teeth portions PT without sandwiching another comb teeth portion PT.

[0165] FIG. 36 is a diagram plotting the maximum value of the reception level of the pen signal PS obtained when the ODD / EVEN method is adopted and the maximum value of the reception level of the pen signal PS obtained when the A / B / C method is adopted, for each distance (pen height) from the touch surface 3a to the pen tip of the electromagnetic induction pen 2. From the results of this figure, it is understood that according to the A / B / C method, the reception level of the pen signal PS is greater than that of the ODD / EVEN method at any pen height.

[0166] FIG. 32(b) is a diagram collectively depicting the distribution of the reception levels of the pen signal PS received when the pen tip of the electromagnetic induction pen 2 is at each position in the x direction, with respect to the position detection device 3 according to the present embodiment (i.e., the position detection device 3 adopting the A / B / C method). As is clear when compared with FIG. 32(a), when the A / B / C method is adopted, the reception level of the pen signal PS is greater than that when the ODD / EVEN method is adopted, whether in the vicinity of the folding line FL or at a position away from the folding line FL. Therefore, it can be said that according to the position detection system 1 according to the present embodiment, an improvement in the reception level of the pen signal PS in the vicinity of the folding line FL is realized.

[0167] As described above, according to the position detection system 1 according to the present embodiment, as a method for detecting the position of the electromagnetic induction pen 2, the A / B / C method of shifting the virtual loop coil at a distance shorter than the distance between the two comb teeth portions PT constituting the virtual loop coil is adopted, so that it becomes possible to increase the reception intensity of the pen signal PS in the vicinity of the folding line FL of the foldable display.

[0168] In addition, in the present embodiment, the distance (the first distance) between the two comb teeth portions PT constituting the virtual loop coil is the distance between two adjacent comb teeth portions PT sandwiching one comb tooth portion PT, and the shift distance (the second distance) of the virtual loop coil is the distance between two adjacent comb teeth portions PT without sandwiching other comb teeth portions PT. Although an example has been described, as long as the condition that the second distance is shorter than the first distance is satisfied, the specific values of the first distance and the second distance are not limited to the values described in the present embodiment. For example, regarding the first distance, it may be the distance between two adjacent comb teeth portions PT sandwiching two comb teeth portions PT, or it may be the distance between two adjacent comb teeth portions PT sandwiching three comb teeth portions PT. Further, regarding the second distance, it may be the distance between two adjacent comb teeth portions PT sandwiching one comb tooth portion PT, or it may be the distance between two adjacent comb teeth portions PT sandwiching two comb teeth portions PT.

[0169] FIG. 37 is a diagram for explaining the processing performed by the sensor controller 31 according to a modification of the present embodiment. The sensor controller 31 according to this modification adds the pen signal PS (hereinafter referred to as "pen signal PS1") output from the differential amplifier 50 when the switch circuit 30 is in the first state, the pen signal PS (hereinafter referred to as "pen signal PS2") output from the differential amplifier 50 when the switch circuit 30 is in the second state, and the pen signal PS (hereinafter referred to as "pen signal PS3") output from the differential amplifier 50 when the switch circuit 30 is in the third state to obtain an added pen signal PS x and uses it to derive the position of the electromagnetic induction pen 2. The same applies to other differential amplifiers 50. x When the switch circuit 30 is in the first state, as described above, a virtual loop coil is formed by the comb teeth portions PT x and the portion connecting them to the base PB. The pen signal PS1 detected by this virtual loop coil is the comb teeth portion PT SUM and uses it to derive the position of the electromagnetic induction pen 2. The same applies to other differential amplifiers 50.

[0170] As described above, when the switch circuit 30 is in the first state, a virtual loop coil is formed by the comb teeth portions PT x-2 , PT x and the portion connecting them to the base PB. The pen signal PS1 detected by this virtual loop coil is the comb teeth portion PT x-2 , PT x-1and the pen signal PS detected by the virtual loop coil composed of these and the connecting portion between them and the base PB (hereinafter, "pen signal PS x-2 , x-1 is referred to as"), and the comb teeth portion PT x-1 , PT x and the pen signal PS detected by the virtual loop coil composed of these and the connecting portion between them and the base PB (hereinafter, "pen signal PS x-1 , x is referred to as") are added together. The same applies when the switch circuit 30 is in the second state or the third state. The pen signal PS2 is the pen signal PS x-1 , x and the pen signal PS detected by the virtual loop coil composed of these and the connecting portion between them and the base PB of the comb teeth portion PT x , PT x+1 (hereinafter, "pen signal PS x , x+1 is referred to as") are added together, and the pen signal PS3 is the pen signal PS x , x+1 and the pen signal PS detected by the virtual loop coil composed of these and the connecting portion between them and the base PB of the comb teeth portion PT x+1 , PT x+2 (hereinafter, "pen signal PS x+1 , x+2 is referred to as") are added together. Therefore, the added pen signal PS SUM formed by adding the pen signals PS1 to PS3 is, as shown in FIG. 37, PS x-2 , x-1 +2·PS x-1 , x +2·PS x , x+1 +PS x+1 , x+2 and is represented as. This form is nothing other than the form of the added pen signal PS SUM described in the sixth embodiment. Therefore, according to the position detection system 1 according to this modification example, similar to the position detection system 1 according to the sixth embodiment, even if the electromagnetic induction pen 2 is tilted with respect to the touch surface 3a, the position can be detected with high accuracy, and the effect is obtained.

[0171] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist thereof.

Explanation of Signs

[0172] 1 Position detection system 2 Electromagnetic induction pen 3 Position detection device 3a Touch surface 30 Switch circuit 31 Sensor controller 32 Host processor 40,50 Differential amplifier 50~55,60~62,S1,S2,T1,T2 Switches CCx Comb coil LCx,LCy Loop coil LE Linear electrode PB Base PS Pen signal PT Comb tooth part T Terminal pre Precharge signal sel Selection signal

Claims

1. 1. An integrated circuit coupled to an EMR sensor, comprising: The receiving coil of the EMR sensor is composed of a plurality of first loop coils, a plurality of differential amplifiers, each having a first input terminal and a second input terminal; a first wiring that connects one end of each of the plurality of first loop coils to the first input terminal of the corresponding differential amplifier; a second wiring that connects the other end of each of the first loop coils to the second input terminal of the corresponding differential amplifier; a first switch element provided between a power supply wiring to which a predetermined power supply potential is supplied and the first wiring; [0023] An integrated circuit including

2. a second switch element provided between the power supply wiring and the second wiring; The integrated circuit of claim 1 further comprising:

3. A sensor controller connected to the EMR sensor via the integrated circuit according to claim 1 or 2, the first loop coils each extend in a first direction and are arranged side by side in a second direction intersecting the first direction; a transmitting coil of the EMR sensor is configured by a plurality of second loop coils each extending in a second direction and arranged side by side in the first direction; the integrated circuit further includes a switch circuit configured to be capable of switching between a first state in which one end and the other end of a 2n-1th (n is a natural number) first loop coil from one end side in the second direction among the plurality of first loop coils are connected to the first input terminal and the second input terminal of the corresponding differential amplifier, while one end and the other end of the 2nth first loop coil are disconnected from the first input terminal and the second input terminal of the corresponding differential amplifier, and a second state in which one end and the other end of a 2nth first loop coil from one end side in the second direction among the plurality of first loop coils are connected to the first input terminal and the second input terminal of the corresponding differential amplifier, while one end and the other end of the 2n-1th first loop coil are disconnected from the first input terminal and the second input terminal of the corresponding differential amplifier, transmitting an alternating magnetic field from the EMR sensor by sequentially passing a current through each of the plurality of second loop coils; when the current is to flow through the second loop coil that is 2m-1th (m is a natural number) from one end side in the first direction among the plurality of second loop coils, the switch circuit is set to the first state, and when the current is to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the second state, thereby receiving pen signals output from each of the plurality of differential amplifiers. Sensor controller.

4. a first reception mode in which the switch circuit is set to the first state when the current is caused to flow through the second loop coil that is 2m-1th from one end side in the first direction among the plurality of second loop coils, and the switch circuit is set to the second state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; a second reception mode in which the switch circuit is set to the second state when the current is caused to flow through the second loop coil that is 2m-1th from one end side in the first direction among the plurality of second loop coils, and the switch circuit is set to the first state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; configured to alternate between The sensor controller according to claim 3 .

5. 1. An integrated circuit coupled to an EMR sensor, comprising: a receiving coil of the EMR sensor is a comb coil having a configuration in which a plurality of comb teeth each extending in a first direction are connected at one end to a base extending in a second direction intersecting the first direction, a plurality of differential amplifiers, each having a first input terminal and a second input terminal; a switch circuit configured to be able to switch between a first state in which the other end of a 2n-1th (n is a natural number) comb tooth portion from one end side in the second direction and the other end of a 2nth comb tooth portion from the plurality of comb tooth portions are connected to the first input terminal and the second input terminal of the same differential amplifier, and a second state in which the other end of a 2nth comb tooth portion from one end side in the second direction and the other end of a 2n+1th comb tooth portion from the plurality of comb tooth portions are connected to the first input terminal and the second input terminal of the same differential amplifier, [0023] An integrated circuit including

6. A sensor controller connected to the EMR sensor via the integrated circuit of claim 5, a transmitting coil of the EMR sensor is configured by a plurality of loop coils each extending in the second direction and arranged side by side in the first direction; sending an alternating magnetic field from the EMR sensor by sequentially passing a current through each of the plurality of loop coils; when the current is to flow through the loop coil that is 2m-1th (m is a natural number) from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the first state, and when the current is to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the second state, thereby receiving pen signals output from each of the plurality of differential amplifiers. Sensor controller.

7. a first reception mode in which the switch circuit is set to the first state when the current is caused to flow through the loop coil that is 2m-1th from one end side in the first direction among the plurality of loop coils, and the switch circuit is set to the second state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; a second reception mode in which the switch circuit is set to the second state when the current is caused to flow through the loop coil that is 2m-1th from one end side in the first direction among the plurality of loop coils, and the switch circuit is set to the first state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; configured to alternate between The sensor controller according to claim 6.

8. 1. An integrated circuit coupled to an EMR sensor, comprising: The receiving coil of the EMR sensor is configured with a plurality of linear electrodes each extending in a first direction and arranged side by side in a second direction intersecting the first direction, a plurality of differential amplifiers, each having a first input terminal and a second input terminal; wiring that connects an end of a 2n-k-th (k is an odd natural number, and n is a natural number greater than k / 2) linear electrode and an end of a 2n-th linear electrode from one end side in the second direction among the plurality of linear electrodes to the first input terminal and the second input terminal of the same differential amplifier, respectively; [0023] An integrated circuit including

9. a switch circuit configured to be able to switch between a first state in which an end of a 2n-k-th linear electrode and an end of a 2n-th linear electrode from one end side in the second direction among the plurality of linear electrodes are connected to the first input terminal and the second input terminal of the same differential amplifier, and a second state in which an end of a 2n-th linear electrode and an end of a 2n+k-th linear electrode from one end side in the second direction among the plurality of linear electrodes are connected to the first input terminal and the second input terminal of the same differential amplifier, The integrated circuit of claim 8 further comprising:

10. A sensor controller coupled to the EMR sensor via the integrated circuit of claim 9, comprising: a transmitting coil of the EMR sensor is configured by a plurality of loop coils each extending in the second direction and arranged side by side in the first direction; sending an alternating magnetic field from the EMR sensor by sequentially passing a current through each of the plurality of loop coils; when the current is to flow through the loop coil that is 2m-1th (m is a natural number) from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the first state, and when the current is to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, the switch circuit is set to the second state, thereby receiving pen signals output from each of the plurality of differential amplifiers. Sensor controller.

11. a first reception mode in which the switch circuit is set to the first state when the current is caused to flow through the loop coil that is 2m-1th from one end side in the first direction among the plurality of loop coils, and the switch circuit is set to the second state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; a second reception mode in which the switch circuit is set to the second state when the current is caused to flow through the loop coil that is 2m-1th from one end side in the first direction among the plurality of loop coils, and the switch circuit is set to the first state when the current is caused to flow through the loop coil that is 2mth from one end side in the first direction among the plurality of loop coils, thereby receiving pen signals output from each of the plurality of differential amplifiers; configured to alternate between The sensor controller of claim 10.

12. A sensor controller connected to an EMR sensor having a plurality of loop coils, adding, with different weightings, a pen signal received at a first loop coil among the plurality of loop coils and a pen signal received at each of one or more other loop coils located in the vicinity of the first loop coil among the plurality of loop coils; deriving a position of the electromagnetic induction pen using an added pen signal obtained by the addition; Sensor controller.

13. the plurality of loop coils include second and third loop coils each adjacent to the first loop coil, a fourth loop coil adjacent to the second loop coil on an opposite side to the first loop coil, and a fifth loop coil adjacent to the third loop coil on an opposite side to the first loop coil, a weighting in the addition of the pen signals received at the first to third loop coils is set to twice a weighting in the addition of the pen signals received at the fourth and fifth loop coils; The sensor controller of claim 12.

14. 1. An integrated circuit coupled to an EMR sensor, comprising: a receiving coil of the EMR sensor is a comb coil having a configuration in which a plurality of comb teeth each extending in a first direction are connected at one end to a base extending in a second direction intersecting the first direction, a receiving circuit for receiving a pen signal transmitted by the electromagnetic induction pen; a selection circuit that selects two of the plurality of comb tooth portions and connects the selected two comb tooth portions to the receiving circuit; The plurality of comb teeth include first to fourth comb teeth in order from one side in the second direction, the selection circuit performs the selection such that a first state in which the first and third comb tooth portions are selected and a second state in which the second and fourth comb tooth portions are selected appear in sequence; a distance between the first comb tooth portion and the third comb tooth portion and a distance between the second comb tooth portion and the fourth comb tooth portion are both a first distance, a distance between the first comb tooth portion and the second comb tooth portion is a second distance shorter than the first distance; Integrated circuits.

15. the first comb teeth portion and the second comb teeth portion, the second comb teeth portion and the third comb teeth portion, and the third comb teeth portion and the fourth comb teeth portion are disposed adjacent to each other, the first distance is a distance between two adjacent comb tooth portions with one comb tooth portion therebetween, The second distance is a distance between two adjacent comb tooth portions without sandwiching any other comb tooth portion therebetween.

15. The integrated circuit of claim 14.

16. the plurality of comb-tooth portions include a fifth comb-tooth portion on the other side of the fourth comb-tooth portion in the second direction, the selection circuit performs the selection such that the first state, the second state, and a third state in which the third comb tooth portion and the fifth comb tooth portion are selected appear in that order.

16. The integrated circuit of claim 15.

17. A plurality of the receiving circuits are provided, the selection circuit is a circuit that selects two of the plurality of comb tooth portions for each of the reception circuits and connects the two selected comb tooth portions to the reception circuits; the plurality of comb-tooth portions include the first to fifth comb-tooth portions for each receiving circuit, in that order from one side in the second direction; the selection circuit performs the selection such that a first state in which the corresponding first and third comb tooth portions are selected, a second state in which the corresponding second and fourth comb tooth portions are selected, and a third state in which the corresponding third comb tooth portion and the fifth comb tooth portion are selected appear in that order for each of the receiving circuits.

17. The integrated circuit of claim 16.

18. the plurality of receiving circuits include a first receiving circuit and a second receiving circuit adjacent to each other; the fourth and fifth comb teeth corresponding to the first receiving circuit are the same as the first and second comb teeth corresponding to the second receiving circuit, 20. The integrated circuit of claim 17.

19. A sensor controller coupled to the EMR sensor via the integrated circuit of claim 16, comprising: controlling the selection circuit so that the first state, the second state, and the third state appear in sequence; Sensor controller.

20. deriving a position of the electromagnetic induction pen using an added pen signal obtained by adding together the pen signal output from the receiving circuit in the first state, the pen signal output from the receiving circuit in the second state, and the pen signal output from the receiving circuit in the third state; 20. The sensor controller of claim 19.

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