Sensor device, integrated circuit, and method for detecting indicator

Abstract

The purpose of the present invention is to prevent an increase in power consumption while replacing a Tx coil with a linear electrode. A sensor device is provided with: a linear electrode EL group extending parallel to each other; a loop coil LCx group intersecting the linear electrode EL group; and a sensor controller 31. A sensor controller 31 sequentially sends an alternating magnetic field from a linear electrode EL group, detects an alternating magnetic field generated by an indicator from the alternating magnetic field by using a toroidal coil LCx group, and determines a linear electrode group comprising a part of the linear electrode EL group on the basis of the detection result. A process for generating an alternating magnetic field in at least a portion of the linear electrode group is executed a plurality of times, a two-dimensional position of the indicator is derived using a plurality of result values detected by at least a portion of the toroidal coil LCx group as a result of execution of each process, and the linear electrode group is updated in accordance with the derived two-dimensional position.

Description

Technical Field

[0001] The invention relates to a sensor device, an integrated circuit and a method for detecting an indicator. Background Art

[0002] As one of the methods for detecting the position of an electromagnetic induction pen within the panel surface of a tablet terminal, etc., an electromagnetic induction method (EMR method) is known. The EMR method tablet terminal has a sensor for pen detection arranged within the panel surface (hereinafter referred to as "EMR sensor") and a sensor controller connected to the EMR sensor. The EMR sensor is configured to include a plurality of Tx coils arranged in the y direction and a plurality of Rx coils arranged in the x direction. The sensor controller sends out alternating magnetic fields from the plurality of Tx coils in sequence, and uses each Rx coil to receive a reflected signal (hereinafter referred to as "pen signal") sent by the electromagnetic induction pen each time, thereby detecting the position of the electromagnetic induction pen and receiving the data sent by the electromagnetic induction pen.

[0003] An example of an EMR sensor is disclosed in Patent Document 1. The EMR sensor described in the document is configured as follows: in order to suppress the price increase, the driving electrode (linear electrode supplied with a driving signal for display) in the display device is used as a Tx coil, and the signal line (wiring supplied with an image signal) in the display device is used as an Rx coil. The generation of the alternating magnetic field by the driving electrode is performed as follows: two driving electrodes are selected by a selection signal, and a current flows from one end of the driving electrode on one side to the other end, and on the other hand, for the driving electrode on the other side, the same current flows from the other end to one end. In this document, the driving electrodes and signal lines in the display device are also used as touch electrodes for detecting fingers by electrostatic capacitance.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6698386 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In order to generate a magnetic field of a required size in the Tx coil of the EMR sensor, it is necessary to flow a current with an amplitude larger than that of a display drive signal or the like. If such a large current is flown to the linear electrode as a substitute for the Tx coil, the power consumption will increase because the DC resistance of the linear electrode is larger than that of a general Tx coil. Therefore, a technology is required that can prevent an increase in power consumption while using a linear electrode instead of the Tx coil.

[0009] Therefore, one object of the present invention is to provide a sensor device capable of preventing an increase in power consumption while using a linear electrode instead of a Tx coil.

[0010] In addition, in the case where an alternating magnetic field is generated by selecting two linear electrodes using a selection signal, causing a current to flow from one end of one linear electrode to the other end and causing the same current to flow from the other end of the other linear electrode to one end, as in the invention described in Patent Document 1, a phase shift occurs between the two linear electrodes, and as a result, noise is superimposed on the magnetic field detected by the Rx coil, which requires improvement.

[0011] Therefore, another object of the present invention is to provide a sensor device, an integrated circuit, and a method of detecting an indicator that can reduce noise superimposed on a magnetic field detected by an Rx coil when a linear electrode is used instead of a Tx coil.

[0012] Means for solving problems

[0013] A sensor device according to one aspect of the present invention detects an indicator, wherein the sensor device comprises: a linear electrode group extending parallel to each other; a detection coil group crossing the linear electrode group; and an integrated circuit connected to the linear electrode group and the detection coil group, wherein the integrated circuit sequentially sends out an alternating magnetic field from the linear electrode group, uses the detection coil group to detect an alternating magnetic field generated by the indicator according to the alternating magnetic field, determines a linear electrode group composed of a part of the linear electrode group based on a result of the detection, executes a process of sending out an alternating magnetic field from at least a part of the linear electrode group multiple times, derives a two-dimensional position of the indicator using a plurality of result values ​​detected by at least a part of the detection coil group as a result of the execution of each process, and updates the linear electrode group based on the derived two-dimensional position.

[0014] An integrated circuit on one aspect of the present invention is connected to a linear electrode group extending parallel to each other and a detection coil group intersecting the linear electrode group, to detect an indicator, wherein an alternating magnetic field is sequentially sent out from the linear electrode group, the detection coil group is used to detect an alternating magnetic field generated by the indicator based on the alternating magnetic field, a linear electrode group composed of a part of the linear electrode group is determined based on the result of the detection, a process of sending out an alternating magnetic field from at least a part of the linear electrode group is performed multiple times, a two-dimensional position of the indicator is derived using a plurality of result values ​​detected by at least a part of the detection coil group as a result of the execution of each process, and the linear electrode group is updated based on the derived two-dimensional position.

[0015] A method according to one aspect of the present invention uses a linear electrode group extending parallel to each other and a detection coil group intersecting the linear electrode group to detect an indicator, including: sending out an alternating magnetic field in sequence from the linear electrode group, using the detection coil group to detect an alternating magnetic field generated by the indicator according to the alternating magnetic field, and determining a linear electrode group composed of a part of the linear electrode group based on a result of the detection; executing a process of sending out an alternating magnetic field from at least a part of the linear electrode group multiple times, and deriving a two-dimensional position of the indicator using a plurality of result values ​​detected by at least a part of the detection coil group as a result of executing each process; and updating the linear electrode group based on the derived two-dimensional position.

[0016] A sensor device detection indicator according to another aspect of the present invention comprises: a linear electrode group extending parallel to each other; a detection coil group crossing the linear electrode group; and an integrated circuit connected to the linear electrode group and the detection coil group, wherein the integrated circuit is configured to supply a first alternating current to one end in the length direction of at least one first linear electrode in the linear electrode group, and on the other hand, supply a second alternating current to one end in the length direction of at least one second linear electrode in the linear electrode group that is different from the first linear electrode, wherein the first alternating current and the second alternating current are generated in such a manner that their respective time differentials are in anti-phase with each other.

[0017] An integrated circuit according to another aspect of the present invention is connected to a linear electrode group extending parallel to each other and a detection coil group intersecting the linear electrode group, and detects an indicator, wherein a first alternating current is supplied to one end in the length direction of one or more first linear electrodes in the linear electrode group, and on the other hand, a second alternating current is supplied to one end in the length direction of one or more second linear electrodes in the linear electrode group that are different from the one or more first linear electrodes, and the first alternating current and the second alternating current are generated in such a manner that their respective time differentials are in anti-phase with each other.

[0018] A method according to another aspect of the present invention detects an indicator using a group of linear electrodes extending parallel to each other and a group of detection coils intersecting the group of linear electrodes, and includes: a step of generating a first alternating current and a second alternating current satisfying a relationship in which their respective time differentials are in anti-phase with each other; and a step of supplying the first alternating current to one end in the length direction of one or more first linear electrodes in the group of linear electrodes, and on the other hand, supplying the second alternating current to one end in the length direction of one or more second linear electrodes in the group of linear electrodes that are different from the one or more first linear electrodes.

[0019] Effects of the Invention

[0020] According to the sensor device, integrated circuit and method for detecting an indicator of one aspect of the present invention, once the linear electrode group is determined, the two-dimensional position of the indicator can be derived by supplying current only to a specified number of linear electrodes constituting the linear electrode group, thereby preventing an increase in power consumption while using linear electrodes instead of Tx coils.

[0021] According to the sensor device, integrated circuit, and indicator detection method of another aspect of the present invention, a phase shift can be prevented from occurring between two linear electrodes, thereby reducing noise superimposed on the magnetic field detected by the Rx coil when the linear electrodes are used instead of the Tx coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a diagram showing the configuration of a position detection system 1 according to the first embodiment of the present invention.

[0023] Figure 2 It is shown Figure 1 FIG. 2 is a diagram showing the internal structure of the switch unit 30.

[0024] Figure 3 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the finger F. FIG.

[0025] Figure 4 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0026] Figure 5 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0027] Figure 6 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0028] Figure 7 (a) is a diagram showing a method of supplying an alternating current to the linear electrode EL in the present embodiment, and (b) is a diagram showing a method of supplying an alternating current in a comparative example.

[0029] Figure 8 (a) is shown in Figure 7 (a) is a diagram showing the result of measuring the current flowing to each linear electrode EL in the detection area PA1, and (b) is a diagram showing the result of measuring the current flowing to each linear electrode EL in the detection area PA1. Figure 7 FIG. 5 (b) is a diagram showing the result of measuring the current flowing to each linear electrode EL in the probe area PA2 shown in FIG.

[0030] Fig. 9 (a) and (b) are graphs plotting the measurement results of the phase difference θ, the amplitude A, and the amplitude B in the comparative example for a plurality of cases where the total parasitic capacitance is different.

[0031] Fig.10 (a) is a diagram showing waveforms of various signals related to the present embodiment, and (b) is a diagram showing a method of supplying various signals related to a comparative example.

[0032] Fig.11 30 is a diagram for explaining the reception signal Rx supplied from the differential amplifier 30 i to the sensor controller 31 .

[0033] Fig.12 2 is a diagram for explaining a reception signal Rx according to the first comparative example.

[0034] Fig.13 2 is a diagram for explaining a received signal Rx according to a second comparative example.

[0035] Fig.14 The figure shows the simulation of the electromagnetic induction pen P located in the toroidal coil LCx. n The above diagram is a result of the level of the pen signal received by each loop coil LCx in its vicinity.

[0036] Fig.15 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 .

[0037] Fig.16 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 .

[0038] Fig.17 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 .

[0039] Fig.18 1 is a diagram showing the internal structure of the switch unit 30 arranged in the position detection device 3 constituting the position detection system 1 according to the second embodiment of the present invention.

[0040] Fig.19 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0041] Fig. 20 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0042] Fig.21 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0043] Fig. 22 1 is a diagram showing the internal structure of the switch unit 30 provided in the position detection device 3 constituting the position detection system 1 according to the third embodiment of the present invention.

[0044] Fig.23 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0045] Fig.24 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0046] Fig.25 1 is a diagram showing a state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P.

[0047] Fig.26 (a) to (c) schematically show Figure 23~Figure 25 (d) to (f) are diagrams showing the supply method of alternating current to the six linear electrodes EL respectively by the methods shown in (a) to (c). m ~EL m+5 Supplying an alternating current i A 、i B Diagram of the equivalent circuit of the case.

[0048] Fig. 27 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 .

[0049] Fig.28 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 .

[0050] Fig.29 2 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 . DETAILED DESCRIPTION

[0051] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0052] Figure 1 1 is a diagram showing the structure 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 P and a position detection device 3. The electromagnetic induction pen P is a pen (indicator) that supports position detection by an EMR method, and is configured to include a resonant circuit including a coil and a capacitor.

[0053] The position detection device 3 is a device (sensor device) that supports the position detection of the electromagnetic induction pen P of the EMR method, and is configured to include a plurality of circular coils LCx (detection coil group), a plurality of linear electrodes EL (linear electrode group), a switch unit 30, a sensor controller 31, and a host processor 32. The position detection device 3 of a typical example is a tablet terminal or a laptop computer whose display surface also serves as a touch surface, but the position detection device 3 may also be configured using a digitizer or the like that does not have a display surface.

[0054] The x and y directions shown in the figure are directions within the touch surface and are orthogonal to each other. A plurality of annular coils LCx are formed so as to extend in the y direction (first direction) and are arranged in the x direction (second direction). On the other hand, a plurality of linear electrodes EL are formed so as to extend in the x direction and are arranged in the y direction. Each annular coil LCx and each linear electrode EL are connected to the switch unit 30 at both ends.

[0055] The switch unit 30 is a set of switches composed of a plurality of switches for switching the connection between the plurality of loop coils LCx and the connection between the plurality of loop coils LCx and the plurality of linear electrodes EL and the sensor controller 31. The switch unit 30 may be provided in a dedicated circuit substrate or integrated circuit, or may be provided in the same integrated circuit as the sensor controller 31. The switching state of the switch unit 30 is controlled by the sensor controller 31.

[0056] Figure 2 30. For simplicity, in this figure, only five loop coils LCx and five linear electrodes EL are shown (loop coils LCx n-2 ~LCx n+2 , Linear Electrode EL m-2 ~EL m+2 ). This point is related to the following Figure 3~Figure 6 , Figure 18~Figure 21 The same is true. Figure 2 As shown in FIG. 1 , the switch section 30 includes five types of switches 30 a to 30 f , a drive circuit 30 g , a wiring section 30 h , a differential amplifier 30 i , and an operational amplifier 30 j .

[0057] The switch 30a is a structure for supplying an alternating current Tx_EMR for generating an alternating magnetic field on the touch surface to a plurality of linear electrodes EL, and is configured to have four input pins connected to the drive circuit 30g and an output pin provided for each linear electrode EL. Each output pin is connected to one end of the corresponding linear electrode EL in the x direction (length direction). The switch 30a plays a role of connecting each input pin to any output pin according to the control of the sensor controller 31.

[0058] The drive circuit 30g generates an AC current i according to the AC current Tx_EMR supplied from the sensor controller 31. A 、i B (Refer to Figure 4~Figure 6 ) and supplies it to the linear electrode EL via the switch 30a. The drive circuit 30g is configured to supply an AC current i to two of the four input pins of the switch 30a. A (first alternating current) and supplies alternating current i to the other two B (Second alternating current).

[0059] AC current i A The AC current i is generated by amplifying the AC current Tx_EMR using a buffer circuit, for example. B is the AC current i A The current is generated in such a way that the time differentials of the two currents are in opposite phase with each other. If this relationship is expressed in a mathematical expression, it becomes the following equation (1). The relationship in equation (1) can be said to be that as the alternating current i A The increase in the AC current i B The decrease in the amount of AC current i A The decrease in the AC current i B The increase in the amount of the supply AC current i A The increase in potential of the other end of each of the one or more linear electrodes EL in the longitudinal direction relative to the one end becomes larger, and the AC current i is supplied. B The relationship is that the amount of potential increase at one end of each of the one or more linear electrodes EL in the longitudinal direction becomes larger than that at the other end.

[0060]

[0061] A typical AC current i that satisfies the relationship of formula (1) is B It is expressed by the following formula (2). Where A is an arbitrary constant. When A=0, the AC current i B becomes an alternating current i A In this case, the AC current i A and the alternating current i B On the other hand, when A is greater than the alternating current i A When the maximum value of the AC current i is large, A and the alternating current i B The AC current i A The inversion signal can be generated, for example, using an inversion buffer circuit. Figure 2An example using this inverting buffer circuit is shown in FIG.

[0062]

[0063] Accepts AC current i A 、i B The potential at the other end of each linear electrode EL supplied with the AC current i is preferably set to A The potential generated at one end of the linear electrode EL is the same as the potential generated when an alternating current i is supplied. B The potential at the midpoint of the potential generated at one end of the linear electrode EL. When A=0, this potential becomes 0 (ie, ground potential).

[0064] The switch 30b is a structure for supplying a touch detection signal Tx_TP for detecting the position of the finger F to the plurality of linear electrodes EL, and is configured as a group of input pins and output pins provided for each linear electrode EL. The touch detection signal Tx_TP is supplied from the sensor controller 31 to each input pin. Each output pin is connected to the corresponding linear electrode EL. The switch 30b plays a role of connecting each input pin to the corresponding output pin according to the control of the sensor controller 31.

[0065] The switch 30f is a structure for switching between a state in which the other end of the linear electrode EL in the x direction (length direction) is connected to the potential of the above-mentioned midpoint and a floating state in which nothing is connected. Figure 2 The case where the potential of the midpoint is the ground potential is shown in FIG. Figure 2 As shown in FIG. 1 , the switch 30 f in this case is configured to include a set of an input pin and a ground pin provided for each linear electrode EL. The following description will be continued on the premise that the potential of the above-mentioned midpoint is the ground potential.

[0066] Each input pin of the switch 30f is connected to the other end of the corresponding linear electrode EL in the x direction (length direction). On the other hand, each ground pin of the switch 30f is connected to a ground end to which a ground potential is supplied. The switch 30f is provided because: when the sensor controller 31 detects the position of the electromagnetic induction pen P, it is preferable to make the other end of the x direction of each linear electrode EL the ground potential as described above, and on the other hand, when the sensor controller 31 detects the position of the finger F, it is necessary to make the other end of the x direction of each linear electrode EL float. The switch 30f plays a role in switching the connection state between each input pin and the corresponding ground pin according to the control of the sensor controller 31.

[0067] The switches 30c~30e and the wiring portion 30h are a structure for supplying the pen signal received by each ring coil LCx (a signal represented by an alternating magnetic field generated by the electromagnetic induction pen P based on the alternating magnetic field generated by the alternating current Tx_EMR) to the differential amplifier 30i and supplying the touch detection signal Tx_TP received by each ring coil LCx to the operational amplifier 30j.

[0068] Specifically, the switch 30c includes an input pin provided for each end of the loop coil LCx and four output pins provided for each input pin. The switch 30c functions to connect each input pin to any of the corresponding four output pins under the control of the sensor controller 31.

[0069] The wiring portion 30h is configured to include four wirings L1 to L4. The four output pins of each input pin of the switch 30c are provided corresponding to the four wirings L1 to L4 and are connected to the corresponding wirings.

[0070] The switch 30d is a switch that connects the wiring L1 to the non-inverting input terminal of the differential amplifier 30i and connects the wiring L2 to the inverting input terminal of the differential amplifier 30i under the control of the sensor controller 31. The switch 30e is a switch that connects the wiring L4 to the input terminal of the operational amplifier 30j under the control of the sensor controller 31. The initial states of the switches 30d and 30e are both open (non-connected state).

[0071] The differential amplifier 30i is a circuit that generates a reception signal Rx_EMR by amplifying the voltage difference between the non-inverting input terminal connected to the wiring L1 and the inverting input terminal connected to the wiring L2, and together with the sensor controller 31, constitutes a receiving circuit for the pen signal. In addition, the operational amplifier 30j is a circuit that generates a reception signal Rx_TP in an electrostatic capacitance manner by amplifying the voltage difference between the input terminal and the ground terminal, and together with the sensor controller 31, constitutes a receiving circuit for the touch detection signal Tx_TP. The input terminal of the operational amplifier 30j is connected to the wiring L4 of the wiring portion 30h via the switch 30e, whereby the reception signal Rx_TP becomes a signal obtained by amplifying the signal appearing in the wiring L4. A parallel capacitor for removing high-frequency noise is provided in the operational amplifier 30j. The reception signal Rx_EMR generated by the differential amplifier 30i and the reception signal Rx_TP generated by the operational amplifier 30j are both supplied to the sensor controller 31.

[0072] return Figure 1. The sensor controller 31 is an integrated circuit having a function of detecting the position of the electromagnetic induction pen P within the touch surface by an EMR method and a function of detecting the position of the finger F on the touch surface by an electrostatic capacitance method. Regarding the electromagnetic induction pen P, it is further configured to also have a function of acquiring data sent by the electromagnetic induction pen P by demodulating the pen signal sent by the electromagnetic induction pen P. The detection of the position of the electromagnetic induction pen P, the acquisition of data from the electromagnetic induction pen P, and the detection of the position of the finger F are performed in a time-division manner. The sensor controller 31 is configured to sequentially supply the detected position and the acquired data to the host processor 32.

[0073] The host processor 32 uses the position and data supplied from the sensor controller 31 to perform processing such as moving the cursor displayed on the display surface and generating stroke data indicating the trajectory of the electromagnetic induction pen P or the finger within the touch surface. Regarding the stroke data, the host processor 32 also performs processing 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 the user's instructions.

[0074] Below, while referring to Figure 3~Figure 6 , while the processing of detecting the positions of the electromagnetic induction pen P and the finger F performed by the sensor controller 31 will be specifically described.

[0075] first, Figure 3 30 is a diagram showing the state of the switch unit 30 when the sensor controller 31 of the present embodiment detects the position of the finger F. As shown in the figure, the sensor controller 31 in this case controls the switch 30b so that each input pin is connected to the corresponding output pin. As a result, the touch detection signal Tx_TP is supplied from the sensor controller 31 to one end of each linear electrode EL in the x direction. In addition, the sensor controller 31 controls the switch 30f so that each input pin is disconnected from the corresponding ground pin, thereby making the other end of each linear electrode EL in the x direction float.

[0076] The specific content of the touch detection signal Tx_TP generated by the sensor controller 31 can be represented by the matrix A shown in the following formula (3). The matrix A is a square matrix having a plurality of rows corresponding to the plurality of linear electrodes EL. 11 The left side of the suffix marked with (e.g., etc.) indicates the output order from the sensor controller 31, and the right side indicates the number of the linear electrode EL. M is the total number of the linear electrodes EL. The specific value of each element is either "1" or "-1". The matrix A is preferably an orthogonal matrix, but it does not have to be an orthogonal matrix.

[0077]

[0078] The sensor controller 31 generates a touch detection signal Tx_TP for each column of the matrix A and supplies it to each linear electrode EL. The touch detection signal Tx_TP of a typical example is a binary pulse signal that becomes high when the corresponding element of the matrix A is 1 and becomes low when the corresponding element of the matrix A is 1. Hereinafter, the touch detection signal Tx_TP corresponding to one column of the matrix A is referred to as a "partial touch detection signal Tx_TP".

[0079] The sensor controller 31 performs processing to connect each loop coil LCx to the operational amplifier 30j in sequence while maintaining the switch 30e in the connected state while supplying a partial touch detection signal Tx_TP to each linear electrode EL. Specifically, the switch 30c is controlled so that each loop coil LCx is connected to the wiring L4 at both ends in sequence. Figure 3 , showing the toroidal coil LCx n This is an example of a case where the wiring L4 is connected.

[0080] Here, if the mth linear electrode EL m With the nth toroidal coil LCx n The static capacitance formed between them is C mn , then in the portion corresponding to the x-th column of the matrix A, the touch detection signal Tx_TP is supplied to each linear electrode EL and the n-th loop coil LCx n When connected to the operational amplifier 30j, the reception signal Rx_TP supplied from the operational amplifier 30j to the sensor controller 31 becomes a value represented by the following equation (4).

[0081]

[0082] Therefore, during the period in which the partial touch detection signal Tx_TP corresponding to each column of the matrix A is supplied, the n-th loop coil LCx n The obtained received signal Rx_TP is represented as a whole by a vector b shown in the following equation (5).

[0083]

[0084] The sensor controller 31 calculates the electrostatic capacitance C of each linear electrode EL by performing the calculation shown in the left side of the following equation (6) on the vector b. mn Separate and obtain. Among them, the matrix A shown in formula (6) -1 is the inverse matrix of matrix A. As shown in formula (6), if matrix A is multiplied by matrix A -1Then it becomes the unit matrix I. Therefore, by performing this operation, the sensor controller 31 can obtain the value of the n-th loop coil LCx as shown in the right side of equation (6). n Each linear electrode EL m The electrostatic capacitance C at the intersection mn Separately obtained.

[0085]

[0086] The sensor controller 31 performs the same calculation as equation (6) on each loop coil LCx to derive the electrostatic capacitance C for each intersection of the linear electrode EL and the loop coil LCx: mn Then, the sensor controller 31 calculates the capacitance C of each capacitor based on the derived capacitance C. mn The position (two-dimensional position) of the finger F is derived from the distribution in the touch surface. Specifically, the position corresponding to the vertex of the distribution may be derived as the position of the finger F.

[0087] then, Figure 4~Figure 6 1 and 10 are diagrams showing the state of the switch unit 30 when the sensor controller 31 detects the position of the electromagnetic induction pen P. As shown in these diagrams, the sensor controller 31 is arranged to sandwich one linear electrode EL. m On one side, two adjacent linear electrodes EL m-1 ,EL m-2 (First linear electrode) supplies an alternating current i A And to the two adjacent linear electrodes EL on the other side m+1 ,EL m+2 (Second linear electrode) supplies an alternating current i B In addition, the sensor controller 31 controls the switch 30f so as to connect each input pin to the corresponding ground pin, thereby making the other end of each linear electrode EL in the x direction into a ground state.

[0088] Through this control, a linear electrode EL is formed. m The analog coil at the center is on the touch surface (especially the linear electrode EL m Hereinafter, generating an alternating magnetic field in this way is referred to as "generating an alternating magnetic field from the linear electrode EL m The sensor controller 31 is configured to sequentially connect all the linear electrodes EL except the four linear electrodes EL located at both ends as the linear electrodes EL. m The same process is performed, and the same alternating magnetic field is sequentially sent out from these linear electrodes EL.

[0089] It should be noted that the four linear electrodes EL excluded from the execution of the above process are preferably arranged outside the touch surface so that the position of the electromagnetic induction pen P can be detected on the entire touch surface. m The AC current flows through two linear electrodes EL on each side, but the AC current may flow through a specified number of linear electrodes EL of one or more. For example, the AC current may flow through one linear electrode EL on each side or three or more linear electrodes EL on each side.

[0090] Here, from Figure 4~Figure 6 It can be understood from the description that the drive circuit 30g is arranged at one end side of the length direction of each linear electrode EL, and the alternating current i A 、i B All are supplied to one end (end on the same side) of the linear electrode EL in the x direction (length direction). The effects achieved by adopting such a configuration will be described in detail below with reference to comparative examples.

[0091] Figure 7 (a) is a diagram showing a method of supplying an alternating current to the linear electrode EL in this embodiment. Figure 7 (b) is a diagram showing a method of supplying alternating current in a comparative example. Figure 7 (a), in this embodiment, for the linear electrode EL m-1 ,EL m-2 , supplying AC current i to one end in the length direction A On the other hand, for the linear electrode EL m+1 ,EL m+2 , supplying AC current i to one end in the length direction B In contrast, in the comparative example, Figure 7 As shown in (b), for the linear electrode EL m-1 ,EL m-2 , supplying AC current i to one end in the length direction A On the other hand, for the linear electrode EL m+1 ,EL m+2 , supplying AC current i to the other end in the length direction A The method for supplying the alternating current shown in the comparative example is a supply method described in Patent Document 1, for example.

[0092] Figure 8 (a) is shown in Figure 7 (a) is a diagram showing the result of measuring the current flowing to each linear electrode EL in the detection area PA1 shown in FIG. Figure 8 (b) is shown in Figure 7The results of measuring the current flowing to each linear electrode EL in the detection area PA2 shown in (b) of FIG. 1 are shown in FIG. The horizontal axis in each figure is time, and the vertical axis is the current value. It should be noted that Figure 8 In (a) and (b), regarding the linear electrode EL m+1 ,EL m+2 The current measured at is plotted after reversal. Figure 8 (a) and (b) of FIG. 5 show a case where the parasitic capacitance of the current path of each linear electrode EL (hereinafter referred to as “total parasitic capacitance”) is 1800 pF.

[0094] It is possible to m The most efficient way to send out an alternating magnetic field is to direct the magnetic field toward the linear electrode EL. m-1 ,EL m-2 The amplitude of the flowing current ( Figure 8 The amplitude A) shown in (b) and the linear electrode EL m+1 ,EL m+2 The amplitude of the flowing current ( Figure 8 The amplitude B) shown in (b) is equal to that of the linear electrode EL m-1 ,EL m-2 The current flowing to the linear electrode EL m+1 ,EL m+2 The phase difference of the inversion signal of the flowing current ( Figure 8 The phase difference θ shown in (b) is 0°. Figure 8 (a) It can be understood that in this embodiment, A=B, θ=0°, which can be said to achieve an ideal state from the perspective of the efficiency of the alternating magnetic field. Figure 8 As shown in (b), in the comparative example, A≠B, θ≠0° (specifically, about 32°). Therefore, it can be said that according to this embodiment, the linear electrode EL can be efficiently performed compared with the comparative example. m The sending of alternating magnetic field.

[0095] Fig. 9 (a) and (b) are graphs plotting the measurement results of the phase difference θ, the amplitude A, and the amplitude B in the comparative example for a plurality of cases where the total parasitic capacitance is different. Fig. 9 The horizontal axis of (a) and (b) is the total parasitic capacitance. Fig. 9 The vertical axis of (a) is the phase difference θ, Fig. 9 The vertical axis of (b) is a numerical value expressing the amplitude B / amplitude A as a percentage. Fig. 9It can be understood from (a) and (b) that in the comparative example, the larger the total parasitic capacitance, the more it deviates from the ideal state. Therefore, it can be said that when the comparative example is adopted, the current path needs to be planned in such a way that the total parasitic capacitance becomes smaller. In contrast, in this embodiment, regardless of the total parasitic capacitance, Figure 8 Since the circuit design is simplified as compared with the comparative example, the current path does not need to be planned so as to reduce the total parasitic capacitance.

[0096] Fig.10 (a) is a diagram showing waveforms of various signals associated with this embodiment, Fig.10 (b) is a diagram showing a method of supplying various signals associated with a comparative example. In these diagrams, the linear electrode EL is shown. m-1 ,EL m-2 The waveform of the current flowing to the linear electrode EL m+1 ,EL m+2 The waveform of the flowing current, the waveform of the voltage (pen signal) generated inside the electromagnetic induction pen P (Pen resonance waveform), and the waveform of the reception signal Rx_EMR detected by the loop coil LCx closest to the electromagnetic induction pen P.

[0097] First refer to Fig.10 (b), it can be understood that: the sensor controller 31 supplies an alternating current i to the linear electrode EL A During the period (the "alternating magnetic field sending period" shown in the figure), a pen signal is generated inside the electromagnetic induction pen P, and an alternating current i generated by the linear electrode EL appears in the receiving signal Rx_EMR. A The waveform of the reception signal Rx_EMR is formed by superimposing the voltage signal induced in the loop coil LCx by the alternating magnetic field sent from the linear electrode EL on the voltage signal induced in the loop coil LCx by the pen signal sent from the electromagnetic induction pen P. If the sensor controller 31 ends the alternating current i to the linear electrode EL, A , the voltage signal induced by the alternating magnetic field sent from the linear electrode EL disappears, so only the voltage signal induced by the pen signal remains in the received signal Rx_EMR. Although it is not easy to see due to the scale, the alternating current i to the linear electrode EL is AAfter the supply of is completed, the waveform of the receiving signal Rx_EMR becomes the same waveform as the waveform of the pen signal. Therefore, the sensor controller 31 of the comparative example sets the period after the "alternating magnetic field sending period" as the "position deriving and data receiving period" for deriving the position of the electromagnetic induction pen P and receiving the data sent by the electromagnetic induction pen P, and derives the position of the electromagnetic induction pen P and receives the data sent by the electromagnetic induction pen P based on the receiving signal Rx_EMR obtained during this period.

[0098] In contrast, Fig.10 In (a), the waveform of the received signal Rx_EMR becomes the same as the waveform of the pen signal during the entire period including the period when the alternating magnetic field is sent. This is based on: Figure 8 As shown in (a), the linear electrode EL m-1 ,EL m-2 The current flowing to the linear electrode EL m+1 ,EL m+2 There is no phase shift between the flowing currents, so they cancel each other out. m The voltage signal induced in the ring coil LCx by the sent alternating magnetic field does not overlap with the received signal Rx_EMR. That is, it can be said that according to the present embodiment, the noise overlapping with the alternating magnetic field detected by the ring coil LCx is reduced. The sensor controller 31 of the present embodiment makes use of this effect and utilizes the "alternating magnetic field sending period" as the "position derivation period" for deriving the position of the electromagnetic induction pen P. During this period, the position of the electromagnetic induction pen P is derived based on the voltage signal appearing in the ring coil LCx. Therefore, according to the present embodiment, the period for receiving the pen signal for deriving the position of the electromagnetic induction pen P can be ensured to be longer than that of the comparative example. Therefore, compared with the comparative example, the position of the electromagnetic induction pen P can be derived with higher accuracy.

[0099] It should be noted that the sensor controller 31 of the present embodiment does not receive the data sent by the electromagnetic induction pen P during the "alternating magnetic field sending period" because the electromagnetic induction pen P cannot send data during the "alternating magnetic field sending period". Specifically, the electromagnetic induction pen P is configured to change the resonant frequency of the resonant circuit in the electromagnetic induction pen P according to the content of the data to be sent, thereby modulating the frequency of the pen signal, thereby sending data. In the presence of an alternating magnetic field from the position detection device 3, the frequency of the pen signal is fixed to the frequency of the alternating magnetic field. Therefore, even if the resonant frequency of the resonant circuit is changed in the electromagnetic induction pen P, the change will not be reflected in the frequency of the pen signal. Therefore, the electromagnetic induction pen P cannot send data during the "alternating magnetic field sending period".

[0100] return Figure 4~Figure 6The sensor controller 31 generates a signal from the linear electrode EL. m While the alternating magnetic field is being sent, the following processing is performed: while the switch 30d is maintained in the connected state, the three adjacent loop coils LCx are selected as one group in sequence, and the switch 30c is controlled each time so that the three loop coils LCx constituting the selected group are connected in series with respect to the differential amplifier 30i in three connection methods with different connection polarities. Through this processing, the differential amplifier 30i detects the result value indicating the level of the pen signal based on the potential between the two ends of the composite coil constituted by the three loop coils LCx connected in series, and outputs it to the sensor controller 31 as the reception signal Rx_EMR.

[0101] Figure 4~Figure 6 The figure shows the connection under the above three connection modes. Figure 4 In the example, when viewed from the non-inverting input terminal of the differential amplifier 30i, the loop coil LCx n-1 Connect counterclockwise (marked as "-1" in the figure), and then connect the toroidal coil LCx n Connect clockwise (marked as "1" in the figure), and finally connect the toroidal coil LCx n+1 Connect counterclockwise. Figure 5 In the example, when viewed from the non-inverting input terminal of the differential amplifier 30i, the loop coil LCx n-1 Connect clockwise, then connect the toroidal coil LCx n Connect counterclockwise and finally connect the toroidal coil LCx n+1 Connect counterclockwise. Figure 6 In the example, when viewed from the non-inverting input terminal of the differential amplifier 30i, the loop coil LCx n-1 Connect counterclockwise, then connect the toroidal coil LCx n Connect counterclockwise and finally connect the toroidal coil LCx n+1 Connect clockwise.

[0102] Fig.11 3 is a diagram for explaining the reception signal Rx_EMR supplied from the differential amplifier 30i to the sensor controller 31 as a result of the above connection. The pen signal detection periods T1 to T3 shown in the figure are respectively Figure 4~Figure 6 It should be noted that, in fact, the alternating magnetic field sending period is configured in the first half of each signal detection period (refer to Fig.10 ), but in Fig.11 In addition, the actual receiving signal Rx_EMR is as follows Fig.10 As shown in the figure, it decays over time, but for ease of understanding, Fig.11 The attenuation is not depicted in the figure. These points are described later. Fig.12 and Fig.13 The same is true in .

[0103] Reference Fig.11 , it can be understood that: the pen signal received during the pen signal detection period T1 is in the ring coil LCx n and toroidal coil LCx n-1 ,LCx n+1 This is based on the fact that, as mentioned above, the toroidal coil LCx n Become clockwise, the toroidal coil LCx n-1 ,LCx n+1 As a result, if the linear electrode EL in the sensor controller 31 m When an alternating magnetic field is generated in the n-1 ~LCx n+1 The levels of the received pen signals are recorded as level E m,n-1 ~E m,n+1 , then Fig.11 As shown in FIG. 1 , the reception signal Rx_EMR (result value) supplied from the differential amplifier 30i to the sensor controller 31 during the pen signal detection period T1 is expressed as −E m,n-1 +E m,n -E m,n+1 The same is true for the pen signal detection periods T2 and T3, which are represented by +E m,n-1 -E m,n -E m,n+1 , -E m,n-1 -E m,n +E m,n+1 .

[0104] The vector d shown in the following formula (7) series The received signals Rx_EMR received during the pen signal detection periods T1 to T3 are recorded in vector form. As shown in the last line of equation (7), the vector d series It can be transformed into a 3×3 matrix F indicating the connection polarity during each signal detection period and a matrix E indicating the level m,n-1 ~E m,n+1 It should be noted that the matrix F shown in equation (7) becomes a 3×3 Walsh code.

[0105]

[0106] The sensor controller 31 controls the vector d series The calculation shown on the left side of the following equation (8) is performed to convert the level E m,n-1 ~E m,n+1 Separate and obtain. Among them, the matrix F shown in formula (8) -1is the inverse matrix of the matrix F. Therefore, the operation shown on the left side of equation (8) becomes the restoration operation corresponding to the connection polarity of the loop coil LCx in each of the above-mentioned connection methods. As shown in equation (8), if the matrix F is multiplied by the matrix F -1 Then it becomes the unit matrix I. Therefore, the sensor controller 31 can restore the m-th linear electrode EL by performing the restoration operation as shown on the right side of equation (8). m The alternating magnetic field is sent by the toroidal coil LCx n-1 ~LCx n+1 The level E of the pen signal received m,n-1 ~E m,n+1 Separately obtained.

[0107]

[0108] The sensor controller 31 performs the same calculation as equation (8) on each group of loop coils LCx to obtain the value of m When an alternating magnetic field is sent, the level of the pen signal received by each of the plurality of loop coils LCx is separated and obtained. In addition, the sensor controller 31 changes the linear electrode EL that sends the alternating magnetic field. m The same process is performed while obtaining the plurality of linear electrodes EL m The levels of pen signals received by the plurality of loop coils LCx when the alternating magnetic field is respectively sent out. Furthermore, the sensor controller 31 derives the position (two-dimensional position) of the electromagnetic induction pen P based on the distribution of the pen signal levels thus obtained within the touch surface. Specifically, the position corresponding to the vertex of the distribution is derived as the position of the electromagnetic induction pen P. For details on the position detection of the electromagnetic induction pen P performed by the sensor controller 31, refer to Figure 15~Figure 17 Let me explain it in more detail.

[0109] Here, a comparative example in which a pen signal is received by a method different from that of the present embodiment is given to explain one of the effects of using the present embodiment.

[0110] Fig.12 3 is a diagram illustrating a received signal Rx_EMR of the first comparative example. The sensor controller 31 of this comparative example connects one loop coil LCx to the differential amplifier 30i during each pen signal detection period. In this case, the level of the pen signal received by one loop coil LCx is obtained during each pen signal detection period, so the sensor controller 31 can obtain the level of the pen signal received by each loop coil LCx without performing the above-mentioned calculation.

[0111] Fig.13: is a diagram illustrating the received signal Rx_EMR of the second comparative example. The sensor controller 31 of this comparative example connects the three adjacent ring coils LCx in series to the differential amplifier 30i during each pen signal detection period, similar to the present embodiment. However, the sensor controller 31 of this comparative example connects all the ring coils LCx in the same direction (clockwise or counterclockwise). In this case, the levels of the pen signals received by each ring coil LCx cannot be separated by the calculation as described above, but the sensor controller 31 can regard the received signal Rx obtained by the three ring coils LCx as the signal obtained by the ring coil LCx located at the center of the three ring coils LCx and derive the position of the electromagnetic induction pen P.

[0112] Fig.14 The figure shows the simulation of the electromagnetic induction pen P located in the toroidal coil LCx. n In the case of the above, the level of the pen signal received by each loop coil LCx near it (the level after separation in the case of separation acquisition). This figure shows the present embodiment ( Fig.11 )、First Comparative Example ( Fig.12 )、Second Comparative Example ( Fig.13 ) respective results. As shown in the figure, according to the pen signal receiving method of the present embodiment, it is possible to obtain an effect that the receiving level of the pen signal is significantly increased compared to the first and second comparative examples. This is based on the fact that according to the pen signal receiving method of the present embodiment, the pen signal detection period that can be used to obtain the pen signal received by each ring coil LCx is 3 times that of the first and second comparative examples. Here, as described later, if the pen signal detection period of the pen signal in the sensor controller 31 is increased by N times, the level of the received pen signal is increased by N times, and on the other hand, the level of the received noise stops at N. 1 / 2 Therefore, it can be said that according to the pen signal receiving method of the present embodiment, the S / N ratio of the pen signal received in the sensor controller 31 can be improved.

[0113] In addition, according to the pen signal receiving method of the present embodiment, the pen signals received by the plurality of loop coils LCx can be simultaneously received by one receiving circuit in each of the plurality of pen signal detection periods, and the received signal Rx_EMR can be separated into components of each loop coil LCx, so there is no need to extend the pen signal transmission period in order to improve the S / N ratio, and there is no need to add a receiving circuit in order to receive the pen signals in parallel using the plurality of loop coils LCx. Therefore, it can be said that according to the pen signal receiving method of the present embodiment, the S / N ratio of the pen signal received in the sensor controller 31 can be improved without reducing the frequency of position detection and without increasing the circuit scale of the sensor controller 31.

[0114] Hereinafter, when the pen signal detection period of the pen signal in the sensor controller 31 becomes N times, the noise level stops at N. 1 / 2 This point is explained in detail.

[0115] If the received signal Rx obtained during the kth pen signal detection period is set to X k And its variance is expressed as V(X k ), then by the additivity of the variance, the N received signals X1~X1 obtained during the 1st~Nth pen signal detection period are N The variance V of the added signal (hereinafter referred to as the “added signal”) TOTAL As shown in the following formula (9), it is represented by the sum of the variances of the reception signal Rx in each signal detection period.

[0116]

[0117] If we only focus on the noise component included in the received signal Rx, it can be considered that the noise has the same value during all pen signal detection periods, so the variance V of the added signal is TOTAL It is further expressed as the following equation (10): wherein V and σ are the variance and standard deviation in each signal detection period, respectively.

[0118]

[0119] The amount of noise present in the added signal is given by the standard deviation σ of the added signal TOTAL It can be understood from formula (10) that: due to the standard deviation σ TOTAL As shown in the following equation (11), when the pen signal detection period of the pen signal in the sensor controller 31 increases by N times, the noise level stops at N. 1 / 2 times.

[0120]

[0121] Next, regarding the position detection of the electromagnetic induction pen P performed by the sensor controller 31, referring to the flow chart Figure 1 Let me explain it in more detail.

[0122] Figure 15~Figure 17 1 is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P performed by the sensor controller 31. Fig.15After the sensor controller 31 in front of the electromagnetic induction pen P determines the linear electrodes EL except the two linear electrodes EL at the two ends as the selected objects (step S1), the linear electrode EL closest to the end among the selected linear electrodes EL is selected (step S2). In addition, the sensor controller 31 selects three loop coils LCx from the end, and controls the switches 30c~30e to connect the selected three loop coils LCx in the first connection mode (for example, Figure 4 The connection method shown in the figure) is connected to the differential amplifier 30i (step S3).

[0123] Next, the sensor controller 31 starts to send out the alternating magnetic field from the selected linear electrode EL (step S4). Figure 4 As shown in FIG. 1 , two adjacent linear electrodes EL sandwiching the selected linear electrode EL are connected to the AC current i in the driving circuit 30g. A The output terminal (the output terminal of the buffer circuit) of the drive circuit 30g is connected to the two adjacent linear electrodes EL on the other side sandwiching the selected linear electrode EL and the AC current i in the drive circuit 30g. B The sensor controller 31 connects the output terminal of the inverting buffer circuit 30i to start supplying the AC current Tx_EMR to the drive circuit 30g. Then, the sensor controller 31 temporarily stores the level of the reception signal Rx_EMR output from the differential amplifier 30i according to the alternating magnetic field sent in step S4 (step S5). The level of the reception signal Rx_EMR stored here can be, for example, Fig.10 The maximum value in the entire position derivation period (including the position derivation period during the alternating magnetic field sending period and the position derivation period after the alternating magnetic field sending period) shown in (a) can also be the maximum value in the position derivation period after the alternating magnetic field sending period.

[0124] Next, the sensor controller 31 determines whether the processing of steps S4 to S5 has been tried in all connection modes (step S6). Figure 4~Figure 6 The sensor controller 31, which is determined not to have been tried in this determination, controls the switches 30c to 30e to connect the three selected loop coils LCx to the following connection method (for example, Figure 4 The next connection method shown is Figure 5 The connection method shown, Figure 5 The next connection method shown is Figure 6 The circuit 100 is connected to the differential amplifier 30i (connection method shown in the figure) (step S7), and the process returns to step S4.

[0125] On the other hand, the sensor controller 31 which has determined that the trial has been performed in step S6 derives the level of the pen signal for each loop coil LCx based on the levels of the plurality of received signals Rx_EMR temporarily stored through the plurality of trials in step S5 (step S8 ). Specifically, the restoration operation shown in the above equation (8) is performed.

[0126] Next, the sensor controller 31 determines whether the selection of all the loop coils LCx has been completed (step S9). If it is determined that the selection has not been completed, the sensor controller 31 selects three loop coils LCx adjacent to the three loop coils LCx selected last (the three loop coils LCx selected in step S3 or step S10), and controls the switches 30c to 30e to connect them in the first connection mode (for example, Figure 4 After the sensor controller 31 connects the linear electrode EL to the differential amplifier 30i (the connection method shown in the figure) (step S10), the process returns to step S4. On the other hand, if it is determined that the process is completed in step S9, the sensor controller 31 determines whether the selection of all the linear electrodes EL determined as the selection objects in step S1 is completed (step S11). If it is determined that the process is not completed, the sensor controller 31 selects the linear electrode EL adjacent to the linear electrode EL selected last (the linear electrode EL selected in step S2 or step S12) (step S12), and the process returns to step S4.

[0127] The sensor controller 31 which has determined that the process is completed in step S11 determines whether a pen signal ( ) is detected based on the level of the pen signal for each combination of the linear electrode EL and the loop coil LCx obtained by repeating step S8. Fig.16 In one example, the result of this determination is affirmative when there is a level exceeding a predetermined value, and negative otherwise.

[0128] The sensor controller 31 that determines in step S13 that the pen signal is not detected returns Fig.15 On the other hand, the sensor controller 31 determines that the pen signal is detected based on the Fig.15 The position of the electromagnetic induction pen P is derived from the level of the pen signal for each combination of the linear electrode EL and the loop coil LCx derived in step S8 and is output to the host processor 32 (step S14).

[0129] Next, the sensor controller 31 sets a predetermined number of bars (more than the number of bars) based on the position derived in step S14 (in the case of transition from step S28 described later, the position derived in the previous step S28). Fig.15The number of linear electrodes EL determined as the selection object in step S1 is smaller than the number of linear electrodes EL determined as the selection object. Typically, 3 or 4 linear electrodes EL (linear electrode group) and 3n (n is a natural number, typically n=1. However, 3n is a number smaller than the total number of the circular coils LCx) circular coils LCx are determined (updated) as the selection object (step S15).

[0130] Next, the sensor controller 31 selects the linear electrode EL closest to the end of the selected linear electrodes EL (step S16). Then, three loop coils LCx from the end of the selected loop coils LCx are selected, and the selected three loop coils LCx are connected in the first connection mode (for example, Figure 4 The connection method shown in the figure) is connected to the differential amplifier 30i (step S17).

[0131] Move to Fig.17 Then, the sensor controller 31 performs Fig.15 and Fig.16 The same processing as steps S4 to S13 is performed here (steps S18 to S27). However, the processing here is different from the processing of steps S4 to S14 in that in step S5, only the level of the receiving signal Rx_EMR is temporarily stored, while in step S19, a series of digital values ​​(digital values ​​obtained by sampling) constituting the receiving signal Rx_EMR are also stored; in step S9, it is determined whether the selection of all the annular coils LCx is completed, while in step S23, it is determined whether the selection of all the annular coils LCx determined as the selection object in step S15 is completed; in step S11, it is determined whether the selection of all the linear electrodes EL determined as the selection object in step S1 is completed, while in step S25, it is determined whether the selection of all the linear electrodes EL determined as the selection object in step S15 is completed. It should be noted that the series of digital values ​​stored in step S19 may be only Fig.10 The position shown in (a) is derived as a digital value during data reception.

[0132] The sensor controller 31, which determines that the pen signal is detected in step S27, derives the position of the electromagnetic induction pen P and obtains the data sent by the electromagnetic induction pen P, and outputs it to the host processor 32 (step S28). Specifically, the sensor controller 31 derives the position of the electromagnetic induction pen P based on the level of the pen signal of each combination of the linear electrode EL and the loop coil LCx derived in step S22. In addition, the sensor controller 31 demodulates the series of digital values ​​stored in step S19 for the combination of the linear electrode EL and the loop coil LCx closest to the derived position, thereby obtaining the data sent by the electromagnetic induction pen P. After step S28 is completed, the sensor controller 31 returns to step S15 and continues processing.

[0133] By adopting the above-mentioned processing, according to the sensor controller 31 of this embodiment, Fig.16 Once the linear electrode group is determined in step S15, the two-dimensional position of the electromagnetic induction pen P can be gradually updated by sending an alternating magnetic field only from a predetermined number of linear electrodes EL constituting the linear electrode group. Therefore, the linear electrodes EL can be used instead of the Tx coil while preventing an increase in power consumption.

[0134] As described above, according to the position detection system 1 of this embodiment, once the linear electrode group is determined, the two-dimensional position of the electromagnetic induction pen P can be gradually updated by sending an alternating magnetic field only from a specified number of linear electrodes EL constituting the linear electrode group, thereby preventing an increase in power consumption while utilizing the linear electrodes EL instead of the Tx coil.

[0135] In addition, according to the position detection system 1 of this embodiment, it is possible to prevent the linear electrode EL from m-1 ,EL m-2 The current flowing to the linear electrode EL m+1 ,EL m+2 Since a phase shift occurs between the flowing currents, it is possible to reduce noise superimposed on the alternating magnetic field detected by the Rx coil (loop coil LCx) even when the linear electrode EL is used instead of the Tx coil.

[0136] Furthermore, according to the position detection system 1 of the present embodiment, the S / N ratio of the pen signal received in the sensor controller 31 can be improved without reducing the frequency of position detection and increasing the circuit scale of the sensor controller 31 .

[0137] In addition, according to the position detection system 1 of the present embodiment, by configuring a group of linear electrodes EL arranged in the y direction and a group of annular coils LCx arranged in the x direction, it is possible to realize both an EMR sensor and a touch sensor (a sensor for detecting the touch of a finger F by means of electrostatic capacitance). Therefore, compared with the case where an EMR sensor and a touch sensor are separately provided in one position detection device, it is possible to realize lightweighting and cost reduction of the position detection device.

[0138] In addition, according to the position detection system 1 of this embodiment, since the differential amplifier 30i is used to receive the reception signal Rx_EMR, even if there is a deviation in the resistance value between the loop coils LCx, it is possible to suppress the deviation in the level of the pen signal. This is particularly effective when the loop coils LCx are formed of a high-impedance material such as a metal mesh.

[0139] It should be noted that in this embodiment, the matrix F shown in formula (7) is described as an example of a matrix represented by a 3×3 Walsh code, but a matrix represented by a code other than a Walsh code, such as an OVSF code, an M sequence code, or a Baker code, can also be appropriately used as the matrix F (that is, the connection method of the annular coil LCx during each signal detection period can be set in such a way that the matrix F becomes these codes).

[0140] To explain in general, in the case where k loop coils LCx are connected in series with respect to the differential amplifier 30i at the same time (i.e., the sensor controller 31 selects each group of adjacent k loop coils LCx as a group in sequence during the period when the alternating magnetic field is sent from any linear electrode EL, and controls the switch 30c each time in such a manner that the k loop coils LCx constituting the selected group are connected in series with respect to the differential amplifier 30i in k connection methods with different connection polarities), if the rank of the matrix F (a matrix of k rows and k columns) which is the coefficient matrix of the simultaneous equations represented by the following formula (12) is equal to k, the connection method of the loop coils LCx in each signal detection period can be determined based on the matrix F. In other words, if the column vectors of the matrix F are linearly independent of each other, the connection method of the loop coils LCx in each signal detection period can be determined based on the matrix F. This is because, in any case, formula (12) must have a solution.

[0141]

[0142] In addition, in this embodiment, the inverse matrix F of the matrix F is used. -1 The example of performing the restoration operation is to use a matrix other than the inverse matrix. seriesTaking the case of as an example, an example of a restoration operation using the matrix F itself as a matrix that is not the inverse matrix of the matrix F is described.

[0143] In this example, first, the matrix F for restoration and the level of the received signal Rx in the pen signal detection period T1 to T3 are used. m,n-1 +E m,n -E m,n+1 、+E m,n-1 -E m,n -E m,n+1 , -E m,n-1 -E m,n +E m,n+1 , the level of the received signal Rx corresponding to the case where all the columns of the matrix F are 1 is derived. Specifically, a, b, and c are obtained by solving the simultaneous equations shown in the following formula (13), and the level of the received signal Rx corresponding to the case where all the columns of the matrix F are 1 is derived by deriving a+b+c. The level derived in this way becomes +E m,n-1 +E m,n +E m,n+1 .

[0144]

[0145] Next, as shown in the following equation (14), if a column with all element values ​​of 1 is added to the beginning of the matrix F and the value is +E m,n-1 +E m,n +E m,n+1 The row vector d series After adding at the beginning of series By multiplying, we obtain a result obtained by linearly (specifically, 4 times) amplifying the result of the operation of equation (8).

[0146]

[0147] Thus, when using a matrix F that is not the inverse of the matrix F -1 In the case of performing restoration operations using a matrix F, it is necessary to derive the level of the received signal Rx equivalent to the case where all columns of the matrix F are 1, but this is different from using the inverse matrix F of the matrix F. -1 In the same way as the case of restoring the operation, the level E m,n-1 ~E m,n+1 Separately obtained.

[0148] It should be noted that in formula (14), the result of the calculation result of formula (8) is enlarged by 4 times, but this will increase the accuracy of the subsequent calculation, so it is preferred. -1 The same can be said for the case of performing restoration operation.

[0149] The matrix F is the vector d in the case of a 4×4 Walsh code series It is expressed as the following equation (15): wherein vector e is a vector representing the level of the pen signal received by each of the four loop coils LCx.

[0150]

[0151] The inverse matrix F of the matrix F shown in formula (15) is -1 As expressed in formula (16).

[0152]

[0153] Therefore, when performing the restoration operation of the vector e, if the inverse matrix F is calculated as shown in the following formula (17): -1 Multiply by 4, then we can perform the inverse matrix F -1 The restoration operation obtains a vector having a level four times that of the original vector e.

[0154]

[0155] Next, a position detection system 1 according to a second embodiment of the present invention will be described.

[0156] Fig.18 1 is a diagram showing the internal structure of the switch section 30 arranged in the position detection device 3 constituting the position detection system 1 of the present embodiment. The switch section 30 of the present embodiment is different from the switch section 30 of the first embodiment in that the wiring section 30h does not have the wirings L1 and L2, the switch 30c does not have the output pins corresponding to the wirings L1 and L2, and the operational amplifier 30n is provided instead of the differential amplifier 30i. The switch 30d of the present embodiment plays the role of connecting the wiring L4 to the input terminal of the operational amplifier 30n and connecting the wiring L3 to the ground terminal according to the control of the sensor controller 31. In addition, the sensor controller 31 of the present embodiment is different from the sensor controller 31 of the first embodiment in that the three loop coils LCx are connected to the operational amplifier 30n in parallel instead of in series for the position detection of the electromagnetic induction pen P. In other points, the position detection system 1 of the present embodiment is the same as the position detection system 1 of the first embodiment, and therefore, the following description will continue with a focus on the differences from the position detection system 1 of the first embodiment.

[0157] Figure 19~Figure 21 The sensor controller 31 of the present embodiment respectively shows the state of the switch unit 30 when detecting the position of the electromagnetic induction pen P. The sensor controller 31 of the present embodiment detects the position of the electromagnetic induction pen P from the linear electrode EL. mWhile the alternating magnetic field is being sent, the following processing is performed: the three adjacent loop coils LCx are selected as one group, and the switch 30c is controlled each time so that the three loop coils LCx constituting the selected group are connected in parallel to the operational amplifier 30n in three connection methods with different connection polarities. Through this processing, the operational amplifier 30n detects the result value indicating the level of the pen signal based on the potential (with respect to the ground end) of one end of the composite coil constituted by the three loop coils LCx connected in parallel, and outputs it to the sensor controller 31 as the reception signal Rx_EMR.

[0158] Figure 19~Figure 21 The figure shows the connection under the above three connection modes. Fig.19 In the example of FIG. 1 , the loop coil LCx is viewed from the input terminal of the operational amplifier 30n. n-1 ,LCx n+1 Connect the toroidal coil LCx in a counterclockwise direction (denoted as "-1" in the figure). n Connect clockwise (marked as "1" in the figure). Fig. 20 In the example of FIG. 1 , the loop coil LCx is viewed from the input terminal of the operational amplifier 30n. n-1 Connect the toroidal coil LCx clockwise. n ,LCx n+1 Connect counterclockwise. Fig.21 In the example of FIG. 1 , the loop coil LCx is viewed from the input terminal of the operational amplifier 30n. n-1 ,LCx n Connect the toroidal coil LCx counterclockwise. n+1 Connect clockwise.

[0159] As a result of the above connection, the reception signal Rx_EMR supplied from the operational amplifier 30n to the sensor controller 31 is represented by the vector d expressed by the following equation (18): parallel The level E shown in formula (18) m,n-1 ~E m,n+1 The meaning of is the same as that described in the first embodiment. As shown in the last line of equation (18), the vector d parallel This is also similar to the vector d described in the first embodiment. series Similarly, it can be transformed into a 3×3 matrix F indicating the connection polarity in each signal detection period and a matrix indicating the level E m,n-1 ~E m,n+1 The form of the vector product of .

[0160]

[0161] From the vector d parallel is the same as the vector dseries The same form can be understood. In this embodiment, the sensor controller 31 can also parallel Multiply by the inverse of matrix F -1 The toroidal coil LCx n-1 ~LCx n+1 The level E of the pen signal received m,n-1 ~E m,n+1 Separation is obtained. Therefore, the same effect as that of the first embodiment can be obtained by the pen signal receiving method of the present embodiment. Specifically, it is possible to prevent the increase in power consumption while using the linear electrode EL instead of the Tx coil. In addition, it is also possible to reduce the noise superimposed on the alternating magnetic field detected by the Rx coil (annular coil LCx) when using the linear electrode EL instead of the Tx coil. Moreover, the S / N ratio of the pen signal received in the sensor controller 31 can be improved without reducing the frequency of position detection and increasing the circuit scale of the sensor controller 31. However, in this regard, when a plurality of annular coils LCx are connected in parallel, the inductance becomes smaller than that of the case of series connection. Therefore, in this embodiment, the level of the pen signal becomes smaller than that of the first embodiment. Therefore, it can be said that the effect of improving the S / N ratio of the pen signal is higher in the first embodiment than in the present embodiment.

[0162] Next, a position detection system 1 according to a third embodiment of the present invention will be described.

[0163] Fig. 22 1 is a diagram showing the internal structure of the switch unit 30 arranged in the position detection device 3 constituting the position detection system 1 of the present embodiment. For simplicity, only five loop coils LCx are shown in the figure (loop coils LCx n-2 ~LCx n+2 ) and six linear electrodes EL are shown (linear electrodes EL m ~EL m+5 ). This point is related to the following Figure 23~Figure 25 The same is true.

[0164] The switch unit 30 of this embodiment is different from the switch unit 30 of the second embodiment in that it includes a switch 30k instead of the switch 30a and a drive circuit 30m instead of the drive circuit 30g. In addition, the sensor controller 31 of this embodiment is different from the sensor controller 31 of the second embodiment in the following points: in order to detect the position of the electromagnetic induction pen P, the six linear electrodes EL are connected to the six linear electrodes EL. m ~EL m+5At the same time, an alternating current is supplied, and on the other hand, only one toroidal coil LCx is connected to the operational amplifier 30n at the same time. In other respects, the position detection system 1 of this embodiment is the same as the position detection system 1 of the second embodiment, and therefore, the following description will continue with a focus on the differences from the position detection system 1 of the second embodiment.

[0165] The switch 30k is a structure for supplying an alternating current Tx_EMR for generating an alternating magnetic field on the touch surface to a plurality of linear electrodes EL, and is configured to have an output pin provided for each linear electrode EL and two input pins provided for each output pin. Each output pin is connected to one end of the corresponding linear electrode EL in the x direction (length direction). The switch 30k plays a role of connecting each input pin to any output pin for each linear electrode EL under the control of the sensor controller 31.

[0166] The driving circuit 30m generates the above-mentioned alternating current i according to the alternating current Tx_EMR supplied from the sensor controller 31. A 、i B The driving circuit 30m is configured to supply an alternating current i to one of two input pins corresponding to each linear electrode EL. A And supply AC current i to the other side B .

[0167] Figure 23~Figure 25 The sensor controller 31 of the present embodiment respectively shows the state of the switch unit 30 when detecting the position of the electromagnetic induction pen P. The sensor controller 31 of the present embodiment switches the loop coil LCx to the position of the electromagnetic induction pen P. n During the period of connection to the operational amplifier 30n, the following control is performed: the six adjacent linear electrodes EL are sequentially selected while shifting three at a time, and each time the selected six linear electrodes EL are connected to the driving circuit 30m in three connection modes, and an alternating current i is generated in half of the six linear electrodes EL. A And in the remaining half, an alternating current i is generated B The switch 30c is controlled in this manner.

[0168] Figure 23~Figure 25 The figure shows the supply of AC current under the above three connection modes. Fig.23 In the example of the linear electrode EL m+1 ,EL m+3 ,EL m+5 Supplying AC current i A , to the linear electrode EL m ,EL m+2 ,ELm+4 Supplying AC current i B In addition, Fig.24 In the example of the linear electrode EL m+1 ~EL m+3 Supplying AC current i A , to the linear electrode EL m ,EL m+4 ,EL m+5 Supplying AC current i B .exist Fig.25 In the example of the linear electrode EL m+2 ~EL m+4 Supplying AC current i A , to the linear electrode EL m ,EL m+1 ,EL m+5 Supplying AC current i B .

[0169] Fig.26 (a) to (c) schematically show Figure 23~Figure 25 A diagram showing a method of supplying alternating current in each of the above. Fig.26 (d) to (f) show the Fig.26 The method shown in (a) to (c) is to provide 6 linear electrodes EL m ~EL m+5 Supplying an alternating current i A 、i B As shown in these figures, when the linear electrode EL m+k (k is any one of 0, 1, and 2) and the linear electrode EL m+k+3 When an alternating current whose time differentials are mutually opposite in phase flows, regardless of the direction of the linear electrode EL located between them, m+k+1 ,EL m+k+2 Whatever the current flowing, it can be regarded as the current flowing through the linear electrode EL. m+k and linear electrode EL m+k+3 Hereinafter, the loop coil is referred to as a "pseudo loop coil PLC", and in particular, the linear electrode EL m+k ,EL m+k+3 The simulated toroidal coil PLC is called "simulated toroidal coil PLC m+k ". Simulate the toroidal coil PLC m+k The connection polarity is to the linear electrode EL m+k Supply AC current i A And to the linear electrode EL m+k+3 Supply AC current i B (indicated as "-") and to the linear electrode EL m+kSupply AC current i B And to the linear electrode EL m+k+3 Supply AC current i A (denoted as "+" in the figure), the opposite is true.

[0170] If the linear electrode EL m+k Supplying AC current i A And to the linear electrode EL m+k+3 Supplying AC current i B When the toroidal coil LCx n The level of the received pen signal is represented by E m+k,n , then in progress Fig.26 In the case of supplying the alternating current shown in (a), the reception signal Rx_EMR (result value) supplied from the operational amplifier 30n to the sensor controller 31 is expressed as −E m,n +E m+1,n -E m+2,n In progress Fig.26 The same is true for the supply of alternating current shown in (b) and (c), which are respectively represented by E m,n -E m+1,n -E m+2,n , -E m,n -E m+1,n +E m+2,n If it is expressed in vector form, then the vector d is as shown in the following equation (19): tx And, the vector d tx With the above vector d series , vector d parallel Similarly, it can be transformed into a 3×3 matrix F representing the connection polarity of the analog loop coil PLC and a matrix representing the level E m,n ~E m+2,n The form of the vector product of .

[0171]

[0172] From the vector d tx is the same as the vector d series , vector d parallel The same form can be understood. In this embodiment, the sensor controller 31 can also tx Multiply by the inverse of matrix F -1 And will be in the analog toroidal coil PLC m ~PLC m+2 The level E of the pen signal received when the alternating magnetic field is sent out m,n 、E m+1,n 、E m+2,nFurthermore, according to the method for supplying alternating current of this embodiment, compared with the case where the alternating magnetic field is sent out from the three analog loop coils PLC individually, the length of the period during which the alternating magnetic field is sent out from each analog loop coil PLC becomes three times, so the level of the received pen signal becomes three times, while the level of the received noise is limited to three times. 1 / 2 Therefore, it can be said that the method of supplying alternating current of the present embodiment can also improve the S / N ratio of the pen signal received by the sensor controller 31.

[0173] Figure 27~Figure 29 This is a flowchart showing the overall flow of position detection of the electromagnetic induction pen P executed by the sensor controller 31 of this embodiment. Fig. 27 The sensor controller 31 that detects the electromagnetic induction pen P selects a loop coil LCx closest to the end, and connects the selected loop coil LCx to the operational amplifier 30n by controlling the switch 30b (step S30). This process also includes the following processes: the operational amplifier 30n is connected to the wiring L4 and the wiring L3 is grounded by controlling the switch 30d, and on the other hand, the operational amplifier 30j is disconnected from the wiring L4 by controlling the switch 30e.

[0174] Next, the sensor controller 31 selects six linear electrodes EL from the end, and controls the switch 30k to connect them in the first connection mode (for example, Fig.23 The process also includes grounding the other end of each linear electrode EL in the x direction by controlling the switch 30f and not supplying the touch detection signal Tx_TP to each linear electrode EL by controlling the switch 30b.

[0175] Next, the sensor controller 31 starts to send out the alternating magnetic field from the selected linear electrode EL group (step S32). Specifically, the sensor controller 31 starts to supply the alternating current Tx_EMR to the drive circuit 30m. As a result, the alternating current i flows through each of the six linear electrodes EL. A 、i B As a result, the above-mentioned analog loop coil PLC is formed to send out an alternating magnetic field. After that, the sensor controller 31 temporarily stores the level of the receiving signal Rx_EMR output from the operational amplifier 30n according to the alternating magnetic field sent out in step S32 (step S33). The specific content of the level stored here can be compared with that in Fig.15 The specific contents of the levels stored in step S5 are the same.

[0176] Next, the sensor controller 31 determines whether the processing of steps S32 to S33 has been tried in all connection modes (step S34). Figure 23~Figure 25 The processing of steps S32 to S33 is tried for all three connection methods shown. The sensor controller 31 which is determined not to be tried in this determination controls the switch 30k to connect the selected six linear electrodes EL to the following connection method (for example, Fig.23 The next connection method shown is Fig.24 The connection method shown, Fig.24 The next connection method shown is Fig.25 The connecting method shown in the figure) is connected to the driving circuit 30m (step S35), and returns to step S32.

[0177] On the other hand, the sensor controller 31 which has been determined to have been tried in step S34 derives the level of the pen signal of each analog loop coil PLC based on the levels of the plurality of received signals Rx_EMR temporarily stored through the plurality of trials of step S5 (step S36). tx Multiply by the inverse of matrix F -1 Operation (restore operation).

[0178] Next, the sensor controller 31 determines whether the selection of all the linear electrodes EL has been completed (step S37). If it is determined that the selection has not been completed, the sensor controller 31 selects six linear electrodes EL by shifting three and connects them in the first connection mode (for example, Fig.23 After the sensor controller 31 connects the drive circuit 30m (the connection method shown in the figure) to the drive circuit 30m (step S38), the process returns to step S32. On the other hand, if it is determined to be completed in step S37, the sensor controller 31 determines whether the selection of all the loop coils LCx has been completed (step S39). If it is determined to be not completed, the sensor controller 31 selects a loop coil LCx adjacent to the last selected loop coil LCx (the loop coil LCx selected in step S30 or step S40), connects it to the operational amplifier 30n through the control of the switch 30c (step S40), and the process returns to step S32.

[0179] The sensor controller 31 which has been determined to be finished in step S39 determines whether a pen signal ( ) is detected based on the level of the pen signal for each combination of the pseudo loop coil PLC and the loop coil LCx obtained by repeating step S36. Fig.28 In one example, the result of this determination is affirmative when there is a level exceeding a predetermined value, and negative otherwise.

[0180] The sensor controller 31 that determines in step S41 that the pen signal is not detected returns Fig. 27 On the other hand, the sensor controller 31 determines that the pen signal is detected based on the Fig. 27 The position of the electromagnetic induction pen P is derived from the level of the pen signal for each combination of the analog loop coil PLC and the loop coil LCx derived in step S36 and is output to the host processor 32 (step S42).

[0181] Next, the sensor controller 31 determines 3+3n (n is a natural number, typically n=1. However, 3+3n is a number smaller than the total number of linear electrodes EL) linear electrodes EL (linear electrode group) and a specified number (a number less than the total number of annular coils LCx, typically 3 or 4) of annular coils LCx as selection objects based on the position derived in step S42 (in the case of migration from step S56 described later, it is the position derived in the previous step S56) (step S43).

[0182] Next, the sensor controller 31 selects the loop coil LCx closest to the end of the selected loop coil LCx, and connects it to the operational amplifier 30n by controlling the switch 30c (step S44). In addition, the sensor controller 31 selects six linear electrodes EL from the end of the selected linear electrodes EL, and controls the switch 30k to connect the selected six linear electrodes EL in the first connection mode (for example, Fig.23 The connecting method shown in the figure) is connected to the driving circuit 30m (step S45).

[0183] Move to Fig.29 Then, the sensor controller 31 performs Fig. 27 and Fig.28 The same processing as steps S32 to S41 is performed (steps S46 to S55). However, the processing here is different from the processing of steps S32 to S41 in that only the level of the reception signal Rx_EMR is temporarily stored in step S33, and a series of digital values ​​(digital values ​​obtained by sampling) constituting the reception signal Rx_EMR are also stored in step S47, and it is determined in step S37 whether the selection of all the linear electrodes EL is completed, and it is determined in step S51 whether the selection of all the linear electrodes EL determined as the selection object in step S43 is completed, and it is determined in step S39 whether the selection of all the loop coils LCx is completed, and it is determined in step S53 whether the selection of all the loop coils LCx determined as the selection object in step S43 is completed.

[0184] The sensor controller 31, which determines that the pen signal is detected in step S55, derives the position of the electromagnetic induction pen P and obtains the data sent by the electromagnetic induction pen P, and outputs it to the host processor 32 (step S56). Specifically, the sensor controller 31 derives the position of the electromagnetic induction pen P based on the level of the pen signal of each combination of the analog loop coil PLC and the loop coil LCx derived in step S50. In addition, the sensor controller 31 demodulates the series of digital values ​​stored in step S47 for the combination of the analog loop coil PLC and the loop coil LCx closest to the derived position, thereby obtaining the data sent by the electromagnetic induction pen P. After step S56 is completed, the sensor controller 31 returns to step S43 and continues processing.

[0185] By adopting the above-mentioned processing, according to the sensor controller 31 of this embodiment, Fig.28 Once the linear electrode group is determined in step S43, the two-dimensional position of the electromagnetic induction pen P can be gradually updated by sending an alternating magnetic field only from a predetermined number of linear electrodes EL constituting the linear electrode group. Therefore, the linear electrodes EL can be used instead of the Tx coil while preventing an increase in power consumption.

[0186] As described above, through the position detection system 1 of this embodiment, once the linear electrode group is determined, the two-dimensional position of the electromagnetic induction pen P can be gradually updated by sending an alternating magnetic field only from a specified number of linear electrodes EL constituting the linear electrode group, thereby preventing an increase in power consumption while utilizing the linear electrodes EL instead of the Tx coil.

[0187] In addition, according to the position detection system 1 of this embodiment, since the alternating current i A 、i B Since the current is supplied to one end (end on the same side) of each linear electrode EL in the x direction (length direction), it is possible to prevent the phase shift between the currents flowing to each linear electrode EL. Therefore, when the linear electrode EL is used instead of the Tx coil, it is also possible to reduce the noise superimposed on the alternating magnetic field detected by the Rx coil (loop coil LCx).

[0188] As mentioned above, although the preferred embodiment of the present invention has been described, the present invention is not limited to such embodiment at all, and the present invention can be implemented in various forms within the scope not departing from the gist of the present invention.

[0189] For example, in the first embodiment, an example of generating the receiving signal Rx_EMR based on the potential between the two ends of a composite coil composed of three circular coils LCx connected in series is described, and in the second embodiment, an example of generating the receiving signal Rx_EMR based on the potential of one end of a composite coil composed of three circular coils LCx connected in parallel (relative to the potential of the ground end) is described, but when the three circular coils LCx are connected in series, the receiving signal Rx_EMR can also be generated based on the potential of one end of the composite coil composed of the three circular coils LCx (relative to the potential of the ground end), and when the three circular coils LCx are connected in parallel, the receiving signal Rx_EMR can also be generated based on the potential between the two ends of the composite coil composed of the three circular coils LCx.

[0190] In the first and second embodiments, an example is described in which three adjacent loop coils LCx are used as a group to detect the position of the electromagnetic induction pen P. However, two adjacent loop coils LCx may be used as a group, or four or more adjacent loop coils LCx may be used as a group. Alternatively, all loop coils LCx may be used as a group. When n (n≥2) loop coils LCx are used as a group, the matrix F becomes an n×n matrix.

[0191] In the first and second embodiments, the example of generating the reception signal Rx_EMR by changing the mutual connection of the plurality of loop coils LCx using the switch 30c is described, but the reception signal Rx_EMR may be generated by changing the connection between each loop coil LCx and the operation circuit. Fig.11 During the pen signal detection period T1 shown in FIG. 1 , the loop coil LCx n-1 ,LCx n+1 Connect the toroidal coil LCx to the subtraction circuit n The adding circuit is connected to the pen signal detection period T2, and the loop coil LCx n ,LCx n+1 Connect the toroidal coil LCx to the subtraction circuit n-1 The adding circuit is connected to the pen signal detection period T3, and the loop coil LCx n Connect the toroidal coil LCx to the subtraction circuit n-1 ,LCx n+1 Connect to the adding circuit.

[0192] In addition, the technology of the present invention can also be applied to generate a reception signal Rx_EMR corresponding to an arbitrary connection method of the loop coil LCx. For example, the difference E between the loop coil LCx1 and the loop coil LCx2 can be generated. m,1 -Em,2 , a signal obtained by subtracting the added signal of the loop coils LCx3 and LCx4 from the added signal of the loop coils LCx1 and LCx2 (E m,1 +E m,2 )-(E m,3 +E m,4 ). By doing so, it is possible to obtain the level of the pen signal corresponding to any connection method of the loop coil LCx.

[0193] Description of Reference Numerals

[0194] 1 Position detection system

[0195] 3 Position detection device

[0196] 30 Switch

[0197] 30a~30f, 30k switch

[0198] 30g, 30m driving circuit

[0199] 30h Wiring Department

[0200] 30i Differential Amplifier

[0201] 30j, 30n Operational Amplifier

[0202] 31 Sensor Controller

[0203] 32 Host processor

[0204] EL Linear Electrode

[0205] F finger

[0206] L1~L4 wiring

[0207] LCx Toroidal Coils

[0208] P Electromagnetic induction pen

[0209] PA1, PA2 exploration area

[0210] PLC Simulation Toroid

[0211] T1~T3 Pen signal detection period

[0212] Tx, Tx_EMR AC current

[0213] Tx_TP Touch detection signal

[0214] Rx, Rx_EMR, Rx_TP receive signal.

Claims

1. A sensor device for detecting an indicator, wherein: have: The linear electrode groups are arranged to extend parallel to each other; A detection coil group intersecting with the linear electrode group; and An integrated circuit is connected to the linear electrode group and the detection coil group, The integrated circuit sequentially sends out an alternating magnetic field from the linear electrode group, uses the detection coil group to detect the alternating magnetic field generated by the indicator according to the alternating magnetic field, and determines a linear electrode group composed of a part of the linear electrode group based on the detection result. The integrated circuit executes a process of sending an alternating magnetic field from at least a part of the linear electrode group a plurality of times, and derives a two-dimensional position of the indicator using a plurality of result values ​​detected by at least a part of the detection coil group as a result of the execution of each process, The integrated circuit updates the linear electrode group according to the derived two-dimensional position.

2. The sensor device according to claim 1, The two-dimensional position is a position including positions in a first direction in which the linear electrodes constituting the linear electrode group are arranged and positions in a second direction in which the coils constituting the detection coil group are arranged.

3. The sensor device according to claim 1, While the process of sending the alternating magnetic field from at least a part of the linear electrode group is performed the plurality of times, the linear electrode group is not used for detecting the alternating magnetic field generated by the indicator.

4. The sensor device according to claim 1, The process of sending out an alternating magnetic field from at least a part of the linear electrode group is the following process: a specified number of linear electrodes are selected from a plurality of linear electrodes constituting the linear electrode group, a first alternating current is simultaneously supplied to half of the specified number of linear electrodes, and a second alternating current different from the first alternating current is simultaneously supplied to the remaining number of the specified number of linear electrodes.

5. The sensor device according to claim 4, The integrated circuit performs the process of sending an alternating magnetic field from at least a part of the linear electrode group a plurality of times while changing a combination of a linear electrode supplying the first alternating current among the predetermined number of linear electrodes and a linear electrode supplying the second alternating current among the predetermined number of linear electrodes.

6. The sensor device according to claim 1, The process for causing at least a portion of the linear electrode group to generate an alternating magnetic field is the following process: selecting one of the multiple linear electrodes constituting the linear electrode group, simultaneously supplying a first alternating current to one or more linear electrodes adjacent to the selected linear electrode on one side, and simultaneously supplying a second alternating current different from the first alternating current to one or more linear electrodes adjacent to the other side.

7. The sensor device according to any one of claims 4 to 6, The first alternating current and the second alternating current are generated so as to satisfy a relationship in which their time differentials are in anti-phase with each other.

8. A sensor device for detecting an indicator, wherein: have: The linear electrode groups are arranged to extend parallel to each other; A detection coil group intersecting with the linear electrode group; and An integrated circuit is connected to the linear electrode group and the detection coil group, The integrated circuit is configured to supply a first alternating current to one end in the length direction of one or more first linear electrodes in the linear electrode group, and supply a second alternating current to one end in the length direction of one or more second linear electrodes in the linear electrode group that are different from the one or more first linear electrodes, The first alternating current and the second alternating current are generated so as to satisfy a relationship in which their time differentials are in anti-phase with each other.

9. The sensor device according to claim 8, The relationship is the following: As the increase in the first alternating current becomes larger and the decrease in the second alternating current becomes larger, As the amount of decrease of the first alternating current becomes larger, the amount of increase of the second current becomes larger.

10. The sensor device according to claim 8, The relationship is such that as the amount of increase in potential at the other end of each of the one or more first linear electrodes relative to one end in the longitudinal direction increases, the amount of increase in potential at one end of each of the one or more second linear electrodes relative to the other end in the longitudinal direction increases.

11. The sensor device according to claim 8, The one or more first linear electrodes are a predetermined number of linear electrodes adjacent to one side of a linear electrode selected from the linear electrode group. The one or more second linear electrodes are the predetermined number of linear electrodes adjacent to the other side of the one linear electrode.

12. The sensor device according to claim 8, The potential at the other end in the length direction of each of the one or more first linear electrodes and the potential at the other end in the length direction of each of the one or more second linear electrodes are the potentials at the midpoints of the potentials generated at the one end of the one or more first linear electrodes due to the first current and the potentials generated at the one end of the one or more second linear electrodes due to the second current.

13. The sensor device according to claim 12, When the potential of the one or more first linear electrodes is greater than the midpoint, the potential of the one or more second linear electrodes is less than the midpoint.

14. An integrated circuit connected to a group of linear electrodes extending parallel to each other and a group of detection coils intersecting the group of linear electrodes, for detecting an indicator, wherein: The linear electrode group sequentially sends out an alternating magnetic field, the detection coil group detects the alternating magnetic field generated by the indicator according to the alternating magnetic field, and based on the detection result, determines a linear electrode group composed of a part of the linear electrode group. executing a process of sending an alternating magnetic field from at least a portion of the linear electrode group a plurality of times, and deriving a two-dimensional position of the indicator using a plurality of result values ​​detected by at least a portion of the detection coil group as a result of executing each process, The linear electrode group is updated according to the derived two-dimensional position.

15. An integrated circuit connected to a group of linear electrodes extending parallel to each other and a group of detection coils intersecting the group of linear electrodes, for detecting an indicator, wherein: supplying a first alternating current to one end in the length direction of at least one first linear electrode in the linear electrode group, and supplying a second alternating current to the one end in the length direction of at least one second linear electrode in the linear electrode group that is different from the at least one first linear electrode, The first alternating current and the second alternating current are generated so as to satisfy a relationship in which their time differentials are in anti-phase with each other.

16. A method for detecting a pointer, comprising: detecting a pointer using a group of linear electrodes extending parallel to each other and a group of detection coils intersecting the group of linear electrodes, wherein: include: The step of sequentially sending out an alternating magnetic field from the linear electrode group, detecting the alternating magnetic field generated by the indicator according to the alternating magnetic field by the detection coil group, and determining a linear electrode group composed of a part of the linear electrode group based on the detection result; a step of executing a process of sending an alternating magnetic field from at least a part of the linear electrode group a plurality of times, and deriving a two-dimensional position of the indicator using a plurality of result values ​​detected by at least a part of the detection coil group as a result of executing each process; and A step of updating the linear electrode group according to the derived two-dimensional position.

17. A method for detecting a pointer, comprising: detecting a pointer using a group of linear electrodes extending parallel to each other and a group of detection coils intersecting the group of linear electrodes, wherein: include: A step of generating a first alternating current and a second alternating current that satisfy a relationship in which their time differentials are in anti-phase with each other; and A step of supplying a first alternating current to one end in the longitudinal direction of at least one first linear electrode in the linear electrode group, and supplying a second alternating current to the one end in the longitudinal direction of at least one second linear electrode in the linear electrode group that is different from the at least one first linear electrode.

Images