Indicated position detection device and indicated position detection method

Abstract

Provided are an indicated position detection device and an indicated position detection method capable of suppressing a decrease in detection accuracy of an indicated position of an indicator. An indicated position detection device for detecting an indicated position of an indicator is provided with a first transmission unit and a second transmission unit. The first transmission unit transmits a first transmission signal associated with a first process for detecting an indicated position of an indicator. The second transmission unit transmits a second transmission signal associated with a second process different from the first process. In the same period, the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal.

Description

Technical Field

[0001] The invention relates to an indication position detection device and an indication position detection method. Background Art

[0002] In electronic devices such as tablet-type information terminals equipped with flat-panel displays (e.g., liquid crystal panels), indicated position detection devices that detect a position (indicated position) indicated by an indicator such as a finger or a pen are widely used. As position detection methods used in indicated position detection devices, various methods such as a resistance film method, an electromagnetic induction method, and an electrostatic capacitance method are provided.

[0003] Among them, the electromagnetic induction type indicating position detection device, for example, as disclosed in Patent Document 1, is composed of a position detection device with a sensor and an electronic pen as a pen-shaped position indicator with a resonant circuit, wherein the sensor is formed by arranging many annular coils in the X-axis direction and the Y-axis direction of the coordinate axis, and the resonant circuit is composed of a coil as an example of an inductance element wound on a magnetic core and a capacitor.

[0004] The position detection device is configured to supply a transmission signal of a predetermined frequency to the loop coil of the sensor and transmit a magnetic field to the electronic pen. The resonant circuit of the electronic pen is configured to have a resonant frequency corresponding to the frequency of the transmission signal and to accumulate magnetic energy based on electromagnetic induction between the electronic pen and the loop coil of the sensor. Furthermore, the electronic pen feeds back a magnetic field based on the magnetic energy accumulated in the resonant circuit to the loop coil of the sensor of the position detection device.

[0005] The magnetic field from the electronic pen generates an induced voltage in the loop coil of the sensor. The position detection device detects the coordinate values ​​of the X-axis direction and the Y-axis direction of the position on the sensor pointed by the electronic pen based on the values ​​of the induced voltage generated in each loop coil.

[0006] Electromagnetic induction type indicated position detection devices can input the indicated position relatively finely using an electronic pen as an indicator, and are widely used.

[0007] In addition, in the electrostatic capacitance type indicating position detection device, which is a method of detecting the indicated position of an indicating body (finger, pen-type position indicator (electrostatic pen), etc.) used for a touch panel, there are two types of methods, namely, surface type (Surface Capacitive Type: surface capacitive type) and projected type (Projected Capacitive Type: projected capacitive type), and both methods detect the indicated position of the indicating body by detecting the change in the electrostatic coupling state between the sensor electrode and the indicating body. Indicating position detection devices of a method called a cross-point electrostatic coupling method obtained by developing the projected electrostatic capacitance method have also become popular (for example, refer to Patent Document 2).

[0008] Fig. 9 The structure of an example of a sensor of a cross-point electrostatic capacitance type indication position detection device is shown. Fig. 9 As shown, the sensor of the pointing position detection device of the cross-point electrostatic capacitance method is formed by arranging a plurality of upper electrodes Ex in the Y-axis direction (vertical direction) and lower electrodes Ey in the X-axis direction (lateral direction) of the pointing input surface at predetermined intervals in the X-axis direction and the Y-axis direction, respectively, and arranging them orthogonally with a slight gap. In this case, a predetermined electrostatic capacitance Co (fixed capacitance) is formed at the overlapping portion (cross-point) between the upper electrode Ex and the lower electrode Ey.

[0009] Furthermore, at a position where the indicating body 100, such as a position indicator held by the user or a finger of the user, is close to or in contact with the indicating input surface, an electrostatic capacitance Cf is formed between the electrodes Ex and Ey at the position and the indicating body. Furthermore, the indicating body 100 is connected to the ground via a predetermined electrostatic capacitance Cg through the human body. As a result, due to the electrostatic capacitances Cf and Cg, the electrostatic capacitance between the upper electrode Ex and the lower electrode Ey changes at the position indicated by the indicating body 100. In a position detection device of the cross-point electrostatic capacitance method, the position indicated by the indicating body 100 within the indicating input surface is determined by detecting the change in the electrostatic capacitance.

[0010] The change in electrostatic capacitance is detected by the position detection circuit 101. For example, the position detection circuit 101 uses the lower electrode Ey as a transmission electrode to supply a predetermined transmission signal thereto, and uses the upper electrode Ex as a reception electrode to receive a reception signal from the reception electrode, and detects the change in the electrostatic capacitance between the upper electrode Ex and the lower electrode Ey by detecting the change in the current of the reception signal. The position detection circuit 101 detects the position indicated by the indicator by simultaneously supplying transmission signals to all the transmission electrodes and simultaneously performing detection processing of the change in the current of the reception signals from all the reception electrodes.

[0011] The above-mentioned electromagnetic induction type indicated position detection sensor detects an indicated position of an electromagnetic induction type electronic pen as the indicating body, while the electrostatic capacitance type indicated position detection sensor detects an indicated position of a finger or an electrostatic pen as the indicating body, and the objects to be detected are completely different. Therefore, it is conceivable to mount an electromagnetic induction type indicated position detection sensor and an electrostatic capacitance type indicated position detection sensor in one indicated position detection device. According to this indicated position detection device, it is possible to detect, for example, an indication of an indicated position based on a finger using the electrostatic capacitance type indicated position detection sensor while simultaneously detecting an indication of an indicated position based on an electronic pen using the electromagnetic induction type indicated position detection sensor.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Publication No. 2009-86925

[0015] Patent Document 2: Japanese Patent Application Publication No. 2011-3035 Summary of the invention

[0016] Problems to be solved by the invention

[0017] In electronic devices such as tablet-type information terminals equipped with displays (e.g., liquid crystal panels), in order to achieve miniaturization of the electronic devices while maintaining the size of the display panel, supporting narrowing of the frame (frame) surrounding the display panel has become a problem. In addition, in order to support narrowing of the frame, in the electronic devices, it is required to reduce the configuration space of the loop coil and signal line used in the indication position detection device.

[0018] However, when an electronic device is equipped with an electromagnetic induction indicated position detection device and an electrostatic capacitance indicated position detection device, there is a case where the toroidal coil used in the electromagnetic induction indicated position detection device and the signal line for sending a signal and receiving a signal in the electrostatic capacitance indicated position detection device are arranged close to each other. In this case, due to magnetic coupling (interference) between the toroidal coil and the signal line, electromagnetic noise is mixed from the signal line for sending a signal to the toroidal coil, or electromagnetic noise is mixed from the toroidal coil to the signal line for receiving a signal. If electromagnetic noise is mixed from the signal line for sending a signal to the toroidal coil, the S / N ratio of the magnetic field sent from the electronic pen and received by the toroidal coil decreases, and the detection accuracy of the indicated position in the electromagnetic induction indicated position detection device decreases. In addition, if electromagnetic noise is mixed from the toroidal coil to the signal line for receiving a signal, the S / N ratio of the received signal decreases, and the detection accuracy of the indicated position in the electrostatic capacitance indicated position detection device decreases.

[0019] In addition, when an electronic device is equipped with an electromagnetic induction type indication position detection device and an electrostatic capacitance type indication position detection device, there is a case where the loop coil used in the electromagnetic induction type indication position detection device, the signal line used in the electrostatic capacitance type indication position detection device, and the signal line (for example, clock line) for sending a drive signal (for example, clock signal) for driving a display panel are arranged close to each other. In this case, as a result of electromagnetic noise being mixed from the signal line for sending the drive signal to the loop coil used in the electromagnetic induction type indication position detection device and the signal line for receiving the signal in the electrostatic capacitance type indication position detection device, the S / N ratio of the magnetic field sent from the electronic pen and received by the loop coil is reduced, and the accuracy of position detection in the electromagnetic induction type indication position detection device is reduced, or the S / N ratio of the received signal is reduced, and the accuracy of position detection in the electrostatic capacitance type indication position detection device is reduced.

[0020] An object of the present invention is to provide an indicated position detection device and an indicated position detection method capable of suppressing a decrease in the detection accuracy of an indicated position of a pointer.

[0021] Means for solving problems

[0022] According to the present invention, there is provided an indicated position detection device having the following structure.

[0023] [1] An indication position detection device for detecting an indication position of an indicator, wherein the indication position detection device comprises a first transmitting unit and a second transmitting unit, wherein the first transmitting unit transmits a first transmission signal associated with a first process for detecting the indication position of the indicator, and the second transmitting unit transmits a second transmission signal associated with a second process different from the first process, wherein during the same period, a waveform of the first transmission signal and a waveform of the second transmission signal are orthogonal.

[0024] According to the present invention, the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal during the same period, the noise mixed into the reception signal associated with the first or second processing through the first or second transmission signal is suppressed, and the decrease in the position detection accuracy of the first or second processing associated with the reception signal is suppressed.

[0025] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other.

[0026] [2] The indication position detection device according to [1], wherein, in the same period, a value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer.

[0027] [3] The indicated position detection device according to [1] or [2], wherein the first processing is a processing of detecting the indicated position of the indicator by electromagnetic induction, and the second processing is a processing of detecting the indicated position of the indicator by electrostatic capacitance.

[0028] [4] An indication position detection device according to any one of [1] to [3], wherein a transmission period of the first transmission signal overlaps with at least a portion of a transmission period of the second transmission signal.

[0029] [5] The indication position detection device according to [4], wherein the start time point and the end time point of the transmission period of the first transmission signal are the same as the start time point and the end time point of the transmission period of the second transmission signal.

[0030] [6] The indicated position detection device according to [1], wherein the indicated position detection device further comprises a display, the first processing is a processing of detecting the indicated position of the indicator on the display by electromagnetic induction, and the second processing is a processing of driving the display.

[0031] [7] The indication position detection device according to [1], wherein the indication position detection device further comprises a display, the first processing is a processing of detecting the indication position of the indicator on the display by an electrostatic capacitance method, and the second processing is a processing of driving the display.

[0032] [8] An indication position detection device for detecting an indication position of an indicator, wherein the indication position detection device comprises a first transmitting unit, a second transmitting unit, a first receiving unit and a second receiving unit, wherein the first transmitting unit transmits a first transmission signal associated with a first process for detecting the indication position of the indicator, the second transmitting unit transmits a second transmission signal associated with a second process for detecting the indication position of the indicator, the first receiving unit receives a first reception signal associated with the first process, and the second receiving unit receives a second reception signal associated with the second process, and during the same period, a waveform of the first reception signal and a waveform of the second reception signal are orthogonal.

[0033] [9] The indication position detection device according to [8], wherein, in the same period, the value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer.

[0034]

[10] The indicated position detection device according to [8] or [9], wherein the first receiving unit receives the first reception signal during a transmission period of the second transmission signal.

[0035]

[11] An indication position detection device according to any one of [8] to

[10] , wherein the second receiving unit receives the second reception signal during a transmission period of the first transmission signal.

[0036]

[12] An indication position detection device according to any one of [8] to

[11] , wherein a protection interval is provided between a reception period of the first reception signal and a reception period of the second reception signal.

[0037]

[13] A method for detecting an indication position, for detecting an indication position of an indicator, comprising: a step of sending a first transmission signal associated with a first process for detecting the indication position of the indicator; and a step of sending a second transmission signal associated with a second process different from the first process, wherein the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal during the same period.

[0038]

[14] A method for detecting an indication position, for detecting an indication position of an indicator, comprising: a step of sending a first transmission signal associated with a first process for detecting the indication position of the indicator; a step of sending a second transmission signal associated with a second process for detecting the indication position of the indicator; a step of receiving a first reception signal associated with the first process; and a step of receiving a second reception signal associated with the second process, wherein the waveform of the first reception signal and the waveform of the second reception signal are orthogonal during the same period.

[0039] Effects of the Invention

[0040] According to the present invention, it is possible to suppress a decrease in the detection accuracy of the indicated position of the indicator. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is an exploded perspective view showing a configuration example of an electronic device in this embodiment.

[0042] Figure 2 1 is a diagram showing a configuration example of a first sensor and a position detection circuit in the present embodiment.

[0043] Figure 3 1 is a diagram showing a configuration example of a second sensor and a position detection circuit in this embodiment.

[0044] Figure 4 This is a diagram showing an example of a control structure of a display device in this embodiment.

[0045] Figure 5 It is a diagram for explaining problems to be solved in this embodiment.

[0046] Figure 6 It is a diagram for explaining problems to be solved in this embodiment.

[0047] Figure 7 This is a waveform diagram related to the process of detecting the indicated position of the indicator.

[0048] Figure 8 This is a waveform diagram related to the process of detecting the indicated position of the indicator.

[0049] Fig. 9 This is a diagram showing a configuration of an example of a sensor of a cross-point capacitance type indication position detection device. DETAILED DESCRIPTION

[0050] Embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that in each of the drawings, components with the same reference numerals have the same or similar structures.

[0051] (Description of the overall structure)

[0052] Figure 1 1 is an exploded structural diagram showing a structural example of an electronic device 10 (corresponding to the "indication position detection device" of the present invention) in the present embodiment. The electronic device 10 is a tablet-type terminal that has a function of detecting a position indicated by an electromagnetic induction indicator (hereinafter referred to as "first indicator") formed of a position indicator such as an electronic pen using an electromagnetic induction sensor (hereinafter referred to as "first sensor"), and has a function of detecting a position indicated by an indicator such as a finger, a position indicator (electrostatic pen) (hereinafter referred to as "second indicator") on a display screen of a display device using an electrostatic capacitance sensor (hereinafter referred to as "second sensor"), and the two sensors can simultaneously detect the indicated positions of the first and second indicators.

[0053] The electronic device 10 as an example of a tablet terminal includes a first sensor 20 for detecting an indicated position by electromagnetic induction, a display device 30 , a second sensor 40 for detecting a position by electrostatic capacitance, a control circuit board 50 , a planar member 60 , and a housing 70 .

[0054] The display device 30 is composed of a flat panel display such as a liquid crystal display, an organic EL display, etc., and has a display screen 33 on a display substrate 31 in which many display pixels 32 are arranged in the X-axis direction (horizontal) and many display pixels 32 are arranged in the Y-axis direction (vertical) orthogonal to the X-axis direction.

[0055] The first sensor 20 is arranged on the back side of the display screen 33 of the display device 30 so as to overlap with the display device 30. In addition, the second sensor 40 is arranged on the front side of the display screen 33 of the display device 30 so as to overlap with the display screen 33 of the display device 30. Therefore, the first sensor 20 and the second sensor 40 are also arranged in an overlapping relationship.

[0056] Furthermore, the detection area of ​​the first sensor 20 capable of detecting the position indicated by the first indicator, the detection area of ​​the second sensor 40 capable of detecting the position indicated by the second indicator, and the display area of ​​the display screen 33 of the display device 30 are formed to be approximately equal in size and are in an overlapping configuration.

[0057] exist Figure 1 Although not shown in the figure, the first sensor 20 is connected to a position detection circuit of an electromagnetic induction method, and the second sensor 40 is connected to a position detection circuit of an electrostatic capacitance method. The first and second position detection circuits are provided on a control circuit substrate 50, and are connected to the first sensor 20 and the second sensor 40, for example, through a flexible cable. The control circuit substrate 50 is equipped with a microcomputer for controlling the electronic device 10, a control circuit of the display device 30, other electronic components, and a copper foil wiring pattern. It should be noted that there may be multiple control circuit substrates 50 in the electronic device 10. In addition, the first and second position detection circuits may also be provided on a control circuit substrate independent of the control circuit substrate 50.

[0058] The planar member 60 is made of a transparent material such as glass or resin, and one surface 60a thereof serves as an indication surface (operation surface) for indicating a position by a first indicator such as an electronic pen and a second indicator such as a finger or a stylus. The second sensor 40 and the display device 30 are arranged on the surface side opposite to the one surface 60a of the planar member 60.

[0059] The planar member 60 has a shape slightly larger than the detection area of ​​the indicator of the first sensor 20 and the second sensor 40. Figure 1 In the planar member 60, the area 61 enclosed by the dotted line is an area corresponding to the detection area of ​​the indicator of the first sensor 20 and the second sensor 40, and a frame area 62 is formed around the area 61. Although not shown in the figure, the planar member 60 may be formed such that the frame area 62 is made opaque by, for example, screen printing, etc., and only the area 61 is kept transparent.

[0060] The housing 70 is made of, for example, a synthetic resin. A recess 71 is formed in the housing 70 for accommodating the first sensor 20, the display device 30, the second sensor 40, and the control circuit substrate 50. After the first sensor 20, the display device 30, the second sensor 40, and the control circuit substrate 50 are accommodated in the recess 71, the frame region 62 of the planar member 60 is bonded to the frame region 72 of the housing 70, for example, by an adhesive material, thereby closing the recess 71 and assembling the electronic device 10.

[0061] It should be noted that the first sensor 20 may be placed in the base of the display device 30 , and the second sensor 40 may be disposed on the first sensor 20 and the display device 30 .

[0062] Next, refer to Figure 2 The configuration example of the electromagnetic induction type first sensor 20 and the position detection circuit 200 is described. The electronic pen 23 as an example of the first indicator used with the first sensor 20 of this example has a built-in resonance circuit composed of a coil 23L and a capacitor 23C connected in parallel with the coil 23L.

[0063] The first sensor 20 is disposed on the wiring substrate 21 (see FIG. 2 ) via an X-axis direction annular coil group 22X. Figure 1 ) on one surface of the wiring substrate 21 and the Y-axis direction annular coil group 22Y is arranged on the other surface of the wiring substrate 21. The X-axis direction annular coil group 22X and the Y-axis direction annular coil group 22Y are respectively composed of a plurality of rectangular annular coils. In the present embodiment, n annular coils are arranged in the X-axis direction and m annular coils are arranged in the Y-axis direction. The annular coils of the X-axis direction annular coil group 22X and the Y-axis direction annular coil group 22Y are arranged to overlap each other.

[0064] The circular coils constituting the X-axis direction circular coil group 22X are arranged at equal intervals and overlapped one after another in the horizontal direction (X-axis direction) of the detection area for detecting the indicated position of the electronic pen 23. In addition, the circular coils constituting the Y-axis direction circular coil group 22Y are arranged at equal intervals and overlapped one after another in the vertical direction (Y-axis direction) of the detection area.

[0065] A position detection circuit 200 is connected to the first sensor 20. The position detection circuit 200 includes a selection circuit 201, an oscillator 202, a current driver 203 constituting a transmission amplifier, a transmission / reception switching circuit 204, a reception amplifier 205, a detection circuit 206, a low-pass filter 207, a sample-and-hold circuit 208, an A / D (Analog to Digital) conversion circuit 209, and a control circuit 210.

[0066] The X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y are connected to the selection circuit 201. The selection circuit 201 sequentially selects one loop coil of the two loop coil groups 22X and 22Y according to the control of the control circuit 210.

[0067] The oscillator 202 generates an AC signal of frequency f0. The AC signal is supplied to the current driver 203 and converted into a current, and then sent to the transmission and reception switching circuit 204. The transmission and reception switching circuit 204 switches the connection destination (transmission side terminal T, reception side terminal R) connected to the loop coil selected by the selection circuit 201 at a predetermined time under the control of the control circuit 210. The current driver 203 is connected to the transmission side terminal T, and the reception amplifier 205 is connected to the reception side terminal R.

[0068] Therefore, during transmission, the AC signal converted into current in the current driver 203 is supplied to the loop coil selected by the selection circuit 201 via the transmission-side terminal T of the transmission-reception switching circuit 204. In addition, during reception, the induced voltage generated in the loop coil selected by the selection circuit 201 is supplied to the reception amplifier 205 via the selection circuit 201 and the reception-side terminal R of the transmission-reception switching circuit 204 to be amplified, and then sent to the detection circuit 206.

[0069] The induced voltage amplified in the receiving amplifier 205 is detected by the detection circuit 206 and supplied to the A / D conversion circuit 209 via the low-pass filter 207 and the sample-hold circuit 208. The A / D conversion circuit 209 converts the signal supplied via the low-pass filter 207 and the sample-hold circuit 208 from an analog signal to a digital signal and supplies it to the control circuit 210.

[0070] The control circuit 210 performs control for detecting the indicated position. Specifically, the control circuit 210 controls the selection of the loop coil in the selection circuit 201, the signal switching in the transmission / reception switching circuit 204, the timing of the sample-and-hold circuit 208, and the like.

[0071] The control circuit 210 switches the transceiver switching circuit 204 to be connected to the transmitting terminal T, thereby controlling the power supply of the annular coil selected by the selection circuit 201 in the X-axis direction annular coil group 22X or the Y-axis direction annular coil group 22Y to send out a magnetic field. The resonant circuit of the electronic pen 23 functions by receiving the magnetic field sent from the annular coil to accumulate magnetic energy and sending the magnetic field based on the accumulated magnetic energy to the first sensor 20.

[0072] Next, the control circuit 210 switches the transmission / reception switching circuit 204 to be connected to the receiving terminal R. Then, in the respective loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y, an induced voltage is generated by the magnetic field transmitted from the electronic pen 23 as a position indicator.

[0073] The control circuit 210 calculates the coordinate values ​​of the indicated position in the X-axis direction and the Y-axis direction in the detection area of ​​the first sensor 20 based on the voltage values ​​of the induced voltages generated in the respective annular coils. Furthermore, the control circuit 210 detects the position indicated by the electronic pen 23 based on the calculated coordinate values, and the external host (PC) receiving the detection result from the control circuit 210 controls the screen displayed on the display device 30.

[0074] In addition, the control circuit 210 is connected to the control circuit 410 of the position detection circuit 400 of the second sensor 40, and the control circuit 410 exchanges synchronization signals with each other to synchronize the detection operation of the indicated position of the electronic pen with the detection operation of the indicated position of the finger or the position indicator. For example, the control circuit 210 sends a start signal indicating the start of the detection operation of the indicated position of the electronic pen to the control circuit 410. In addition, the control circuit 410 may also send a start signal indicating the start of the detection operation of the indicated position of the finger or the position indicator to the control circuit 210. A control unit that synchronizes the detection operation of the indicated position of the electronic pen with the detection operation of the indicated position of the finger or the position indicator may also be provided between the control circuit 210 and the control circuit 410 independently of the control circuit 210 and the control circuit 410.

[0075] Next, refer to Figure 3 The following describes a configuration example of the second sensor 40 and the position detection circuit 400. The second sensor 40 is a cross-point capacitance type sensor in order to realize multi-touch detection of a plurality of fingers simultaneously.

[0076] The second sensor 40 is formed by forming an electrode group composed of a plurality of light-transmitting electrodes on one surface of a transparent substrate 41 (the surface opposite to the surface facing the display screen 33 of the display device 30). The transparent substrate 41 is formed of, for example, a glass substrate or a resin film substrate.

[0077] The electrode group is composed of a plurality of first electrodes 42X formed in the Y-axis direction (longitudinal direction) and a plurality of second electrodes 42Y formed in the X-axis direction (lateral direction) orthogonal to the Y-axis direction. The first electrodes 42X are arranged at predetermined intervals in the X-axis direction. In addition, the second electrodes 42Y are arranged at predetermined intervals in the Y-axis direction. These first electrodes 42X and second electrodes 42Y are composed of a conductor made of a light-transmitting conductive material (e.g., an ITO film) or a metal mesh.

[0078] The first electrode 42X and the second electrode 42Y are formed on the same side of the transparent substrate 41. Therefore, in the region of the intersection of the mutually orthogonal first electrode 42X and second electrode 42Y, an insulating material is disposed between the first electrode 42X and the second electrode 42Y so as to be electrically insulated from each other.

[0079] The second sensor 40 is connected to a position detection circuit 400 . The position detection circuit 400 includes a transmission signal generation circuit 401 , a transmission electrode selection circuit 402 , a reception electrode selection circuit 404 , a reception signal processing circuit 405 , a position information output circuit 406 , and a control circuit 410 .

[0080] The position detection circuit 400 discretely executes position detection processing at predetermined time intervals (eg, 10 msec) based on the control of the control circuit 410 , thereby detecting a plurality of position indications of the second indicator on the second sensor 40 and obtaining respective position detection results.

[0081] The transmission signal generating circuit 401 and the transmission electrode selecting circuit 402 constitute a transmission signal supply circuit, and the reception electrode selecting circuit 404 and the reception signal processing circuit 405 constitute a signal reception circuit. The first electrode 42X is used as a reception electrode, and the second electrode 42Y is used as a transmission electrode.

[0082] The transmission signal generation circuit 401 supplies a predetermined transmission signal to the transmission electrode selection circuit 402 at a predetermined timing under the control of the control circuit 410. As the predetermined transmission signal, for example, an orthogonal spread code or the like can be used (for example, refer to Japanese Patent Application Laid-Open No. 2021-99827).

[0083] The transmission electrode selection circuit 402 selects a predetermined second electrode 42Y (transmission electrode) according to the selection control of the control circuit 410. The transmission signal from the transmission signal generation circuit 401 is simultaneously supplied to the plurality of second electrodes 42Y (all, even-numbered, or odd-numbered) selected by the transmission electrode selection circuit 402. It should be noted that the transmission electrode selection circuit 402 may not be provided, and the transmission signal may be directly transmitted from the transmission signal generation circuit 401 to all the second electrodes 42Y.

[0084] The reception electrode selection circuit 404 selects a plurality of (all, even-numbered, or odd-numbered) first electrodes 42X according to the control of the control circuit 410 , and supplies reception signals simultaneously received from the selected first electrodes 42X to the reception signal processing circuit 405 .

[0085] Based on the control of the control circuit 410 , the reception signal processing circuit 405 detects the signal change of the reception signal caused by the second indicator such as a finger or a position indicator indicating a position on the second sensor 40 using the first electrode 42X, and supplies the detection output to the position information output circuit 406 .

[0086] The position information output circuit 406 is based on the control of the control circuit 410 and, according to the detection output of the received signal processing circuit 405, generates an indicated position detection signal, i.e., a coordinate output, corresponding to the position indicated by a second indicator such as a finger or a position indicator as a position detection result and outputs it to the control circuit 410 based on the first electrode 42X that generates a signal change in the received signal and the second electrode 42Y that is supplied with the transmitted signal at this time.

[0087] The external host (PC) that receives the position detection result from the position information output circuit 406 from the control circuit 210 controls the screen displayed on the display device 30 based on the position detection result.

[0088] As described above, the position detection device of this embodiment includes the first sensor 20 and the position detection circuit 200 of the electromagnetic induction method, and includes the second sensor 40 and the position detection circuit 400 of the electrostatic capacitance method, and can simultaneously detect the position indication of the first indicator (such as an electronic pen) and the second indicator (such as a finger, a position indicator). The electronic device 10 can perform processing such as changing the display image of the display device 30 based on the detection results of the first indicator and the detection results of the second indicator.

[0089] Next, refer to Figure 4 The control structure example of the display device 30 is described below. The display device 30 is configured to include a display module 301 (corresponding to the "display" of the present invention), a backlight module 302, a gate drive circuit 303, and a source drive circuit 304. The control circuit 34 is mounted on a control circuit substrate 50 (see Figure 1 ). The gate drive circuit 303 and the control circuit 34 are connected via four clock lines (not shown).

[0090] The display module 301 is configured to include row signal lines GL1 to GLn arranged in the vertical direction, column signal lines SL1 to SLm arranged in the horizontal direction, and display pixels 32 (image elements) arranged at each intersection of the row signal lines GL1 to GLn and the column signal lines SL1 to SLm. The display module 301 drives a corresponding one of the row signal lines GL1 to GLn according to the gate signal VG1 to VGn sent from the gate driving circuit 303, and drives each display pixel 32 corresponding to the source signal VS1 to VSm at the brightness indicated by the source signal VS1 to VSm sent from the source driving circuit 304.

[0091] The row signal lines GL1 to GLn are, for example, gate lines, and n of them are arranged in the vertical direction in the display device 30. The row signal lines GL1 to GLn are driven by corresponding gate signals VG1 to VGn sent from the gate drive circuit 303, and relay the exchange of charges between the gate electrodes of the display pixels 32 corresponding to the intersections with the column signal lines SL1 to SLm and the gate drive circuit 303.

[0092] The column signal lines SL1 to SLm are, for example, source lines, and m of them are arranged in the horizontal direction in the display device 30. The column signal lines SL1 to SLm are driven by corresponding source signals VS1 to VSm sent from the source driver circuit 304, and relay the exchange of charges between the source electrodes of the display pixels 32 corresponding to the intersections with the row signal lines GL1 to GLn and the source driver circuit 304.

[0093] The display pixel 32 is, for example, a liquid crystal image element, and a total of n×m display pixels are arranged at the intersections of the row signal lines GL1 to GLn and the column signal lines SL1 to SLm in the display device 30. The gate electrode of the display pixel 32 is connected to one of the row signal lines GL1 to GLn, and the source electrode of the display pixel 32 is connected to one of the column signal lines SL1 to SLm. When the display pixel 32 is supplied with charge to the gate electrode via the row signal line GL1 to GLn connected to the gate electrode, the display pixel 32 displays a corresponding image at a brightness according to the potential of the column signal line SL1 to SLm connected to the source electrode.

[0094] The backlight module 302 is a light source disposed on the back side of the display module 301 , and irradiates light to the display module 301 from the back side.

[0095] The gate drive circuit 303 is a circuit for driving the row signal lines GL1 to GLn, and is arranged in the display module 301 when the display device 30 is viewed from the display screen 33. The gate drive circuit 303 outputs gate signals VG1 to VGn to the corresponding row signal lines GL1 to GLn at the timing of the clock signals CLK1 to CLK4 output from the control circuit 34, thereby sequentially driving the row signal lines GL1 to GLn. In addition, the gate drive circuit 303 supplies and extracts charges to the gate electrodes of the corresponding display pixels 32 via the driven row signal lines GL1 to GLn.

[0096] The source driver circuit 304 is a circuit for driving the column signal lines SL1 to SLm, and is arranged on the lower side of the display module 301 when the display device 30 is viewed from the display screen 33. The source driver circuit 304 outputs source signals VS1 to VSm having a potential set by the control circuit 34 for each column signal line SL1 to SLm to the corresponding column signal lines SL1 to SLn at the timing of the control circuit 34. The source driver circuit 304 supplies the potential of the source signal VS1 to VSm corresponding to the display pixel 32 to the source electrode of the display pixel 32 corresponding to the intersection of the row signal lines GL1 to GLn driven by the gate driver circuit 303 and the column signal lines SL1 to SLm.

[0097] The control circuit 34 is a circuit for controlling the display device 30. When the gate drive circuit 303 starts driving the row signal lines GL1 to GLm, the control circuit 34 generates a start signal indicating the start of driving, and outputs the start signal to the gate drive circuit 303. In addition, the control circuit 34 generates clock signals CLK1 to CLK4 for operating the gate drive circuit 303, and outputs the clock signals CLK1 to CLK4 to the gate drive circuit 303 via four clock lines.

[0098] Furthermore, the control circuit 34 generates a clock signal for operating the source driver circuit 304, and outputs the clock signal to the source driver circuit 304. In addition, the control circuit 34 sets the potential supplied to the source electrode of the corresponding display pixel 32 via the column signal lines SL1 to SLm, and outputs a signal having information of the set potential to the source driver circuit 304.

[0099] (Explanation of the topic)

[0100] In the above-mentioned electronic device 10, in order to achieve miniaturization of the electronic device 10 while maintaining the size of the flat panel display (display module 301), it is a problem to support narrowing of the frame (frame) surrounding the flat panel display (display module 301). In addition, in order to support narrowing of the frame, in the electronic device 10, it is required to reduce the configuration space of the loop coil and the signal line used in the indication position detection device for detecting the indication position of the indicator.

[0101] However, when an electronic device 10 is equipped with both an electromagnetic induction-type indication position detection device and an electrostatic capacitance-type indication position detection device, there is a case where the loop coil used in the electromagnetic induction-type indication position detection device and the signal line for sending a signal and receiving a signal in the electrostatic capacitance-type indication position detection device are arranged close to each other. In this case, electromagnetic noise is mixed from the signal line for sending a signal to the loop coil, or electromagnetic noise is mixed from the loop coil to the signal line for receiving a signal, through magnetic coupling (interference) between the loop coil and the signal line. If electromagnetic noise is mixed from the signal line for sending a signal to the loop coil, the S / N ratio of the magnetic field sent from the electronic pen 23 and received by the loop coil decreases, and the detection accuracy of the indicated position in the electromagnetic induction-type indication position detection device decreases. In addition, if electromagnetic noise is mixed from the loop coil to the signal line for receiving a signal, the S / N ratio of the received signal decreases, and the detection accuracy of the indicated position in the electrostatic capacitance-type indication position detection device decreases.

[0102] For example, Figure 5 As shown, there is a case where the loop coils 22X1 and 22Y1 used in the indicated position detection device of the electromagnetic induction method and the signal line 42X1 for sending signals and the signal line 42Y1 for receiving signals in the indicated position detection device of the electrostatic capacitance method are arranged close to each other. In this case, the loop coil 22X1 and the signal line 42X1 are magnetically coupled (interfered), and electromagnetic noise is mixed into the loop coil 22X1 from the signal line 42X1 for sending signals, and the S / N ratio of the magnetic field sent from the electronic pen 23 and received by the loop coil 22X1 is reduced, and the detection accuracy of the indicated position in the indicated position detection device of the electromagnetic induction method is reduced. In addition, the loop coil 22Y1 and the signal line 42Y1 are magnetically coupled (interfered), and electromagnetic noise is mixed into the signal line 42Y1 for receiving signals from the loop coil 22Y1, and the S / N ratio of the received signal is reduced, and the detection accuracy of the indicated position in the indicated position detection device of the electrostatic capacitance method is reduced.

[0103] In addition, when an electromagnetic induction type indication position detection device and an electrostatic capacitance type indication position detection device are mounted on one electronic device 10, there is a case where the loop coil used in the electromagnetic induction type indication position detection device, the signal line used in the electrostatic capacitance type indication position detection device, and the signal line (for example, clock line) for sending a drive signal (for example, clock signal) for driving a flat panel display (display module 301) are arranged close to each other. In this case, electromagnetic noise is mixed from the signal line for sending the drive signal to the loop coil used in the electromagnetic induction type indication position detection device and the signal line for receiving the signal in the electrostatic capacitance type indication position detection device, and as a result, the S / N ratio of the magnetic field sent from the electronic pen 23 and received by the loop coil decreases, and the accuracy of position detection in the electromagnetic induction type indication position detection device decreases, or the S / N ratio of the received signal decreases, and the accuracy of position detection in the electrostatic capacitance type indication position detection device decreases.

[0104] For example, Figure 6 As shown, there is a case where the loop coil (omitted in the figure) used in the indicated position detection device of the electromagnetic induction method, the signal line (omitted in the figure) used in the indicated position detection device of the electrostatic capacitance method, and the signal line (clock line) for sending the driving signal (clock signal CLK1 to CLK4) for driving the flat panel display (display module 301) are arranged close to each other. In this case, electromagnetic noise is mixed from the clock line for sending the clock signal to the loop coil used in the indicated position detection device of the electromagnetic induction method and the signal line for receiving the signal in the indicated position detection device of the electrostatic capacitance method, and the S / N ratio of the magnetic field sent from the electronic pen 23 and received by the loop coil decreases, and the accuracy of position detection in the indicated position detection device of the electromagnetic induction method decreases, or the S / N ratio of the received signal decreases, and the accuracy of position detection in the indicated position detection device of the electrostatic capacitance method decreases.

[0105] (Description of the structure used to solve the problem)

[0106] In order to solve the above-mentioned problems, the electronic device 10 (pointing position detection device) in this embodiment includes: a first transmitting unit (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y), which transmits a first transmission signal (electromagnetic induction signal) associated with a first process of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction; a second transmitting unit (transmission signal generating circuit 401), which transmits a second transmission signal (transmission signal) associated with a second process of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance; and a first receiving unit (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y), which receives a first reception signal (electromagnetic induction signal) associated with the first process during the transmission period of the second transmission signal. In addition, during the same period, the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction, the center frequency of the first transmission signal (electromagnetic induction signal) and the center frequency of the reception signal (electromagnetic induction signal) are the same in the frequency spectrum represented by the amplitude of the frequency component of each sine wave as a function of frequency. Therefore, in the reception period of the first reception signal (electromagnetic induction signal), the waveform of the first reception signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) are orthogonal, that is, the inner product of the waveform of the first reception signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) becomes 0, and the first reception signal in which the mixing of electromagnetic noise caused by the transmission of the second transmission signal is suppressed can be detected. When the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) are orthogonal in the same period, for example, the value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer. It should be noted that in the frequency spectrum, at the center frequency of the first reception signal (electromagnetic induction signal), the signal power of the second transmission signal (transmission signal) is 0.

[0107] In this embodiment, in order to correctly demodulate the first reception signal (electromagnetic induction signal) even if electromagnetic noise is mixed from the signal line for transmitting the second transmission signal (transmission signal) to the loop coil for receiving the first reception signal (electromagnetic induction signal) during the reception period of the first reception signal (electromagnetic induction signal), the first transmission signal (electromagnetic induction signal) and the second transmission signal (transmission signal) are transmitted orthogonally in advance during the same period. The idea of ​​the two orthogonal signal waveforms is based on orthogonal frequency division multiplexing (OFDM) generally used in wireless communication fields such as wireless LAN and 3GPP (registered trademark) (Third Generation Partnership Project).

[0108] That is, as a process when receiving the first received signal (electromagnetic induction signal), the first received signal and the internal signal corresponding to the second transmitted signal (transmitted signal) are multiplied and integrated during a predetermined period, thereby making it possible to extract (demodulate) the first received signal in which the mixing of electromagnetic noise caused by the transmission of the second transmitted signal is suppressed. In other words, it is possible to separate the noise that is irrelevant to the characteristics of the first received signal to be detected, and it is possible to suppress the decrease in the accuracy of detecting the indicated position of the indicator (electronic pen 23) by the electromagnetic induction method. Here, the internal signal corresponding to the second transmitted signal (transmitted signal) refers to a spread spectrum code that can restore the second transmitted signal, a locally generated signal / data that is consistent with the frequency / mode of the second transmitted signal, etc. It should be noted that when the demodulation process is performed in a digital manner, a correlation operation process or a discrete Fourier transform process (DFT: Discrete Fourier Transform) is performed. In addition, when the demodulation process is performed in an analog manner, an orthogonal demodulation process is performed. It should be noted that the inner product of the waveform of the first received signal (electromagnetic induction signal) and the waveform of the second transmitted signal (transmitted signal) does not necessarily need to be 0, and can also be a degree below a specified value that can suppress the mixing of electromagnetic noise caused by the transmission of the second transmitted signal.

[0109] In addition, in the present embodiment, the electronic device 10 (pointing position detection device) includes: a first transmitting unit (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y) that transmits a first transmission signal (electromagnetic induction signal) associated with a first process of detecting the pointing position of the indicator (electronic pen 23) by electromagnetic induction; a second transmitting unit (transmission signal generating circuit 401) that transmits a second transmission signal (transmission signal) associated with a second process of detecting the pointing position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance; and a second receiving unit (receiving electrode selection circuit 404) that receives a second reception signal associated with the second process during the transmission period of the first transmission signal (electromagnetic induction signal). In addition, during the same period, the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance, the center frequency of the second transmission signal (transmission signal) and the center frequency of the second reception signal in the frequency spectrum are the same. Therefore, during the reception period of the second reception signal, the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second reception signal are orthogonal, that is, the inner product of the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second reception signal becomes 0, and the second reception signal that suppresses the mixing of electromagnetic noise caused by the transmission of the first transmission signal can be detected. In the case where the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second transmission signal (transmission signal) are orthogonal during the same period, for example, the value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer. It should be noted that in the frequency spectrum, at the center frequency of the second reception signal, the signal power of the first transmission signal (electromagnetic induction signal) is 0.

[0110] In this embodiment, in order to ensure that the second reception signal can be correctly demodulated even if electromagnetic noise is mixed into the signal line used for receiving the second reception signal from the annular coil (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y) used for sending the first transmission signal (electromagnetic induction signal) during the reception period of the second reception signal, the first transmission signal (electromagnetic induction signal) and the second transmission signal (transmission signal) are transmitted in advance in the same period so as to be orthogonal to each other.

[0111] That is, as a process when receiving the second received signal, the second received signal and the internal signal corresponding to the first transmitted signal (electromagnetic induction signal) are multiplied and integrated during a predetermined period, thereby being able to extract (demodulate) the second received signal that suppresses the mixing of electromagnetic noise caused by the transmission of the first transmitted signal (electromagnetic induction signal). In other words, it is possible to separate noise that is irrelevant to the characteristics of the second received signal to be detected, and it is possible to suppress the decrease in the accuracy of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by the electrostatic capacitance method. Here, the internal signal corresponding to the first transmitted signal (electromagnetic induction signal) refers to a spread spectrum code that can restore the first transmitted signal, a locally generated signal / data that is consistent with the frequency / mode of the first transmitted signal, etc. It should be noted that when the demodulation process is performed in a digital manner, a correlation operation process or a discrete Fourier transform process (DFT: Discrete Fourier Transform) is performed. In addition, when the demodulation process is performed in an analog manner, an orthogonal demodulation process is performed. It should be noted that the inner product of the waveform of the first transmission signal (electromagnetic induction signal) and the waveform of the second reception signal does not necessarily need to be 0, and can also be below a specified value to the extent that the second reception signal that suppresses the mixing of electromagnetic noise caused by the transmission of the first transmission signal can be extracted.

[0112] Figure 7 is a waveform diagram associated with the process of detecting the indicated position of the indicator. Figure 7 In the figure, the first transmission signal 5A represents the waveform (time change) of the transmission signal (electromagnetic induction signal) associated with the process of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction. The first reception signal 5B represents the waveform (time change) of the reception signal (electromagnetic induction signal) associated with the process of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction. The electromagnetic energy 5C represents the waveform (time change) of the current and voltage flowing to the resonant circuit of the electronic pen 23 in response to the transmission of the first transmission signal 5A (electromagnetic induction signal). The second transmission signal 5D represents the waveform (time change) of the transmission signal associated with the process of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance. The second reception signal 5E represents the waveform (time change) of the reception signal associated with the process of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance. The first transmission signal 5A, the first reception signal 5B, the electromagnetic energy 5C, the second transmission signal 5D, and the second reception signal 5E all represent time (t) on the horizontal axis and represent magnitude on the vertical axis. It should be noted that, with respect to the time on the horizontal axis, the first transmission signal 5A, the first reception signal 5B, the electromagnetic energy 5C, the second transmission signal 5D, and the second reception signal 5E are all represented on the same time axis.

[0113] As shown in the first sending signal 5A, the control circuit 210 switches the transmit-receive switching circuit 204 to be connected to the transmitting side terminal T during the periods D1 and D4, thereby energizing and controlling the annular coil selected by the selection circuit 201 in the X-axis direction annular coil group 22X or the Y-axis direction annular coil group 22Y so that it sends the magnetic field toward the electronic pen 23.

[0114] As shown by the first reception signal 5B, the control circuit 210 switches the transmission and reception switching circuit 204 to be connected to the receiving side terminal R during the period D2, thereby causing each of the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y to receive the magnetic field transmitted from the electronic pen 23. In the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y, an induced voltage is generated by the received first reception signal 5B. The first reception signal 5B received from the electronic pen 23 by each of the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y gradually decreases with the passage of time.

[0115] As shown by electromagnetic energy 5C, during period D1, the magnetic field is sent from the loop coil, which is energized by the transmission of the first transmission signal 5A (electromagnetic induction signal), toward the electronic pen 23, and the magnetic energy accumulated in the resonant circuit of the electronic pen 23 gradually increases. Furthermore, during periods D2 and D3 when the transmission of the magnetic field from the loop coil to the electronic pen 23 is stopped, the electromagnetic energy accumulated in the resonant circuit of the electronic pen 23 gradually decreases as the first reception signal 5B (electromagnetic induction signal) is sent from the electronic pen 23 to each loop coil of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y.

[0116] As shown in the second transmission signal 5D, during the period D1 to D4, the control circuit 410 controls the transmission signal generating circuit 401 to transmit the transmission signal to the second electrode 42Y (transmission electrode) through the transmission electrode selection circuit 402. The periods D1 and D4 during which the annular coil is energized by the transmission of the first transmission signal 5A (electromagnetic induction signal) overlap at least a portion of the transmission period D1 to D4 of the second transmission signal 5D transmitted to the second electrode 42Y (transmission electrode). It should be noted that the start time point and the end time point of the period during which the annular coil is energized by the transmission of the first transmission signal 5A (electromagnetic induction signal) may also be the same as the start time point and the end time point of the transmission period of the second transmission signal 5D transmitted to the second electrode 42Y (transmission electrode).

[0117] As shown by the second reception signal 5E, during the periods D1 to D4, the control circuit 410 controls the reception electrode selection circuit 404 to receive the reception signal from the first electrode 42X.

[0118] In the present embodiment, in period D11 of period D1, the waveform of the first transmission signal 5A sent for power-on control of the annular coil and the waveform of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (finger, position indicator (electrostatic pen)) by electrostatic capacitance, the center frequency of the second reception signal 5E received from the first electrode 42X and the center frequency of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) are the same in the frequency spectrum. Therefore, in the reception period R1 of the second reception signal 5E which is equal to period D11, the waveform of the first transmission signal 5A sent for power-on control of the annular coil and the waveform of the second reception signal 5E received from the first electrode 42X are orthogonal. Figure 7 In the example shown, in the same period D11, the value obtained by subtracting the wave number (3 waves) of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) from the wave number (6 waves) of the first transmission signal 5A sent to control the power supply of the annular coil is a positive integer (3 waves). It should be noted that in this embodiment, by adjusting the phase of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) (for example, shifting 90 degrees), the steep change of the second transmission signal 5D at the start time point and the end time point of the period D11 is avoided, and when the transmission timing of the second transmission signal 5D is offset, the orthogonality between the waveform of the first transmission signal 5A sent to control the power supply of the annular coil and the waveform of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) is suppressed.

[0119] In the present embodiment, in order to ensure that the second receiving signal 5E can be correctly demodulated even if electromagnetic noise is mixed into the signal line for receiving the second receiving signal 5E from the first electrode 42X from the annular coil (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y) used for power control of the first transmitting signal 5A during the receiving period R1 of the second receiving signal 5E, the first transmitting signal 5A and the second transmitting signal 5D are transmitted in advance in the same period D11 which are orthogonal to each other.

[0120] That is, as processing when receiving the second reception signal 5E, the second reception signal 5E received in the reception period R1 and the internal signal corresponding to the first transmission signal 5A sent for controlling the power supply of the annular coil are multiplied and integrated during a specified period. This allows the second reception signal 5E, from which the mixing of electromagnetic noise caused by the transmission of the first transmission signal 5A is suppressed, to be extracted (demodulated). In other words, it is possible to separate noise that is irrelevant to the characteristics of the second reception signal 5E to be detected, and to suppress a decrease in the accuracy of detecting the indicated position of the indicator (finger, electrostatic pen) by an electrostatic capacitance method.

[0121] In addition, based on the principle of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction, the center frequency of the first transmission signal 5A sent to control the power supply of the circular coil in the frequency spectrum is the same as the center frequency of the first reception signal 5B (electromagnetic induction signal) received from the electronic pen 23. Therefore, in the reception period R2 of the first reception signal 5B sent from the electronic pen 23 in the period D2, the waveform of the first reception signal 5B, for example, the waveform of the resonant frequency in the resonant circuit of the electronic pen 23 (the resonant frequency changes due to the writing pressure of the electronic pen 23) and the waveform of the second transmission signal 5D sent to the second electrode 42Y (transmitting electrode) are orthogonal. In other words, the inner product of the waveform of the first reception signal 5B and the waveform of the second transmission signal 5D becomes 0.

[0122] It should be noted that, in the reception period R2 for receiving the first reception signal 5B, the waveform of the first reception signal 5B (electromagnetic induction signal) received from the electronic pen 23 and the waveform of the second reception signal 5E received from the first electrode 42X are orthogonal, that is, the inner product of the waveform of the first reception signal 5B and the waveform of the second reception signal 5E is 0. Furthermore, in the same period R2, the value obtained by subtracting the number of waves (3 waves) of the second reception signal 5E from the number of waves (6 waves) of the first reception signal 5B is a positive integer (3 waves).

[0123] In the present embodiment, in order to ensure that the first receiving signal 5B can be correctly demodulated even if electromagnetic noise is mixed from the signal line for sending the second transmitting signal 5D to the second electrode 42Y (transmitting electrode) to the annular coil (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y) for receiving the first receiving signal 5B from the electronic pen 23 during the receiving period R2 of the first receiving signal 5B, the first transmitting signal 5A and the second transmitting signal 5D are transmitted in advance in the same period D11 which are orthogonal to each other.

[0124] That is, as processing when receiving the first reception signal 5B, the first reception signal 5B received in the reception period R2 and the internal signal corresponding to the second transmission signal 5D sent to the second electrode 42Y (transmission electrode) are multiplied and integrated during a specified period. This allows the first reception signal 5B, which is suppressed from mixing with electromagnetic noise caused by the transmission of the second transmission signal 5D, to be extracted (demodulated). In other words, noise that is irrelevant to the characteristics of the first reception signal 5B to be detected can be separated, and a decrease in the accuracy of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction can be suppressed.

[0125] It should be noted that a period G corresponding to the guard interval is provided between the reception period R1 for receiving the second reception signal 5E from the first electrode 42X and the reception period R2 for receiving the first reception signal 5B (electromagnetic induction signal) from the electronic pen 23. This can alleviate the adverse effects (a decrease in the detection accuracy of the first reception signal 5B and the second reception signal 5E, and thus the detection accuracy of the indicated position) caused by the shift in the timing of receiving the second reception signal 5E from the first electrode 42X and the shift in the timing of receiving the first reception signal 5B from the electronic pen 23), and can ensure the time until the waveform of the first reception signal 5B received from the electronic pen 23 stabilizes after the first transmission signal 5A is transmitted for the power-on control of the loop coil. In addition, when the second transmission signal 5D transmitted to the second electrode 42Y (transmission electrode) is a spread spectrum code and the spread spectrum code is switched from negative (-) to positive (+) between the reception period R1 and the reception period R2 (see Figure 7 ), it is also possible to avoid a decrease in the detection accuracy of the first reception signal 5B received from the electronic pen 23 due to the influence of this switching.

[0126] In addition, in the present embodiment, the electronic device 10 (indication position detection device) includes: a first transmitting unit (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y), which transmits a first transmission signal (electromagnetic induction signal) associated with a first process of detecting the indication position of the indicator (electronic pen 23) by electromagnetic induction; a second transmitting unit (control circuit 34), which transmits a second transmission signal (clock signal) associated with a second process of driving the display (display module 301); and a first receiving unit (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y), which receives a first reception signal (electromagnetic induction signal) associated with the first process during the transmission period of the second transmission signal. In addition, during the same period, the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction, the center frequency of the first received signal and the center frequency of the first transmitted signal are the same in the frequency spectrum. Therefore, during the reception period of the first received signal, the waveform of the first received signal and the waveform of the second transmitted signal are orthogonal, that is, the inner product of the waveform of the first received signal and the waveform of the second transmitted signal becomes 0, and the first received signal in which the mixing of electromagnetic noise caused by the transmission of the second transmitted signal is suppressed can be detected. When the waveform of the first transmitted signal and the waveform of the second transmitted signal are orthogonal during the same period, for example, the value obtained by subtracting the wave number of the second transmitted signal from the wave number of the first transmitted signal is a positive or negative integer. It should be noted that in the frequency spectrum, at the center frequency of the first received signal, the signal power density of the second transmitted signal is 0.

[0127] In this embodiment, in order to ensure that the first reception signal can be correctly demodulated even if electromagnetic noise is mixed from the signal line (clock line) used for sending the second transmission signal to the circular coil used for receiving the first reception signal during the reception period of the first reception signal, the first transmission signal and the second transmission signal (clock signal) are transmitted in advance in the same period so as to be orthogonal to each other.

[0128] That is, as a process when receiving the first received signal (electromagnetic induction signal), the first received signal and the internal signal corresponding to the second transmission signal (clock signal) are multiplied and integrated for a predetermined period, thereby making it possible to extract (demodulate) the first received signal in which the mixing of electromagnetic noise caused by the transmission of the second transmission signal is suppressed. In other words, noise irrelevant to the characteristics of the first received signal to be detected can be separated, and the decrease in the accuracy of detecting the indicated position of the indicator (electronic pen 23) by the electromagnetic induction method can be suppressed. Here, the internal signal corresponding to the second transmission signal (clock signal) refers to a spread spectrum code that can restore the second transmission signal, a locally generated signal / data that is consistent with the frequency / mode of the second transmission signal, etc. It should be noted that, when the demodulation process is performed in a digital manner, a correlation operation process or a discrete Fourier transform process (DFT: Discrete Fourier Transform) is performed. In addition, when the demodulation process is performed in an analog manner, an orthogonal demodulation process is performed. It should be noted that the inner product of the waveform of the first received signal (electromagnetic induction signal) and the waveform of the second transmitted signal (clock signal) does not necessarily need to be 0, and can also be a degree below a specified value that can suppress the mixing of electromagnetic noise caused by the transmission of the second transmitted signal.

[0129] In addition, in this embodiment, the electronic device 10 (pointing position detection device) includes: a first transmitting unit (transmitting signal generating circuit 401) that transmits a first transmission signal (transmitting signal) associated with a first process of detecting the pointing position of the pointing body (finger, electrostatic pen) by electrostatic capacitance; a second transmitting unit (control circuit 34) that transmits a second transmission signal (clock signal) associated with a second process of driving the display (display module 301); and a first receiving unit (receiving electrode selection circuit 404) that receives a first reception signal associated with the first process during the transmission period of the second transmission signal. In addition, during the same period, the waveform of the first transmission signal (transmitting signal) and the waveform of the second transmission signal (clock signal) are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (finger, electrostatic pen) by electrostatic capacitance, the center frequency of the first receiving signal and the center frequency of the first transmitting signal are the same in the frequency spectrum. Therefore, during the reception period of the first receiving signal, the waveform of the first receiving signal and the waveform of the second transmitting signal (clock signal) are orthogonal, that is, the inner product of the waveform of the first receiving signal and the waveform of the second transmitting signal becomes 0, and the first receiving signal that suppresses the mixing of electromagnetic noise caused by the transmission of the second transmitting signal can be detected. When the waveform of the first transmitting signal and the waveform of the second transmitting signal are orthogonal, for example, the value obtained by subtracting the wave number of the second transmitting signal from the wave number of the first transmitting signal is a positive or negative integer. It should be noted that in the frequency spectrum, at the center frequency of the first receiving signal, the signal power of the second transmitting signal (clock signal) is 0.

[0130] In this embodiment, in order to ensure that the first received signal can be correctly demodulated even if electromagnetic noise is mixed from the signal line (clock line) used for sending the second transmitted signal (clock signal) to the signal line used for receiving the first received signal during the reception period of the first received signal, the first transmitted signal and the second transmitted signal are transmitted in advance in the same period so as to be orthogonal to each other.

[0131] That is, as a process when receiving the first received signal, the first received signal and the internal signal corresponding to the second transmitted signal (clock signal) are multiplied and integrated during a predetermined period, thereby being able to extract (demodulate) the first received signal that suppresses the mixing of electromagnetic noise caused by the transmission of the second transmitted signal. In other words, it is possible to separate the noise that is irrelevant to the characteristics of the first received signal to be detected, and it is possible to suppress the decrease in the accuracy of detecting the indicated position of the indicator (finger, electrostatic pen) by the electrostatic capacitance method. Here, the internal signal corresponding to the second transmitted signal refers to a spread spectrum code that can restore the second transmitted signal, a locally generated signal / data that is consistent with the frequency / mode of the second transmitted signal, etc. It should be noted that when the demodulation process is performed in a digital manner, a correlation operation process or a discrete Fourier transform process (DFT: Discrete Fourier Transform) is performed. In addition, when the demodulation process is performed in an analog manner, an orthogonal demodulation process is performed. It should be noted that the inner product of the waveform of the first reception signal and the waveform of the second transmission signal does not necessarily need to be 0, and may be less than a specified value to the extent that the first reception signal can be extracted with electromagnetic noise caused by the transmission of the second transmission signal suppressed.

[0132] Figure 8 is a waveform diagram associated with the process of detecting the indicated position of the indicator. Figure 8 , the first transmission signal 6A represents the waveform (time change) of the transmission signal (electromagnetic induction signal) associated with the process of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction. The first reception signal 6B represents the waveform (time change) of the reception signal (electromagnetic induction signal) associated with the process of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction. The second transmission signal 6C represents the waveform (time change) of the clock signal CLK1 associated with the process of driving the display (display module 301). The second transmission signal 6D represents the waveform (time change) of the clock signal CLK2 associated with the process of driving the display (display module 301). The first transmission signal 6E represents the waveform (time change) of the transmission signal associated with the process of detecting the indicated position of the indicator (finger, electrostatic pen) by electrostatic capacitance. The first reception signal 6F represents the waveform (time change) of the first reception signal associated with the process of detecting the indicated position of the indicator (finger, electrostatic pen) by electrostatic capacitance. The first transmission signal 6A, the first reception signal 6B, the second transmission signals 6C and 6D, the first transmission signal 6E, and the first reception signal 6F all represent time (t) on the horizontal axis and represent magnitude on the vertical axis. It should be noted that, regarding the time on the horizontal axis, the first transmission signal 6A, the first reception signal 6B, the second transmission signals 6C and 6D, the first transmission signal 6E, and the first reception signal 6F are all represented on the same time axis.

[0133] As shown in the first sending signal 6A, the control circuit 210 switches the transmit-receive switching circuit 204 to be connected to the transmitting side terminal T during the periods D1 and D4, thereby energizing and controlling the annular coil selected by the selection circuit 201 in the X-axis direction annular coil group 22X or the Y-axis direction annular coil group 22Y so that it sends the magnetic field toward the electronic pen 23.

[0134] As shown by the first reception signal 6B, the control circuit 210 switches the transmission and reception switching circuit 204 to be connected to the receiving side terminal R during the period D2, thereby causing each of the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y to receive the magnetic field transmitted from the electronic pen 23. In the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y, an induced voltage is generated by the received first reception signal 6B. The first reception signal 6B received from the electronic pen 23 by each of the loop coils of the X-axis direction loop coil group 22X and the Y-axis direction loop coil group 22Y gradually decreases with the passage of time.

[0135] As shown in the second transmission signal 6C, during the periods D1 to D4 , the control circuit 34 generates a clock signal CLK1 for operating the gate drive circuit 303 , and outputs the clock signal CLK1 to the gate drive circuit 303 via the clock line.

[0136] As shown in the second transmission signal 6D, during the periods D1 to D4, the control circuit 34 generates a clock signal CLK2 having a phase different from that of the clock signal CLK1 for operating the gate drive circuit 303, and outputs the clock signal CLK2 to the gate drive circuit 303 via the clock line.

[0137] As indicated by the first transmission signal 6E, during the periods D1 to D4 , the control circuit 410 controls the transmission signal generation circuit 401 to transmit the transmission signal to the second electrode 42Y (transmission electrode) via the transmission electrode selection circuit 402 .

[0138] As indicated by the first reception signal 6F, during the periods D1 to D4, the control circuit 410 controls the reception electrode selection circuit 404 to receive the reception signal from the first electrode 42X.

[0139] In the present embodiment, in period D11 of period D1, the waveform of the second transmission signal 6D output from the control circuit 34 and the waveform of the first transmission signal 6E transmitted to the second electrode 42Y (transmitting electrode) are orthogonal. Here, based on the principle of detecting the indicated position of the indicator (finger, electrostatic pen) by electrostatic capacitance, the center frequency of the first reception signal 6F received from the first electrode 42X and the center frequency of the first transmission signal 6E transmitted to the second electrode 42Y (transmitting electrode) are the same in the frequency spectrum. Therefore, in the reception period R1 of the first reception signal 6F which is equal to period D11, the waveform of the second transmission signal 6D output from the control circuit 34 and the waveform of the first reception signal 6F received from the first electrode 42X are orthogonal. Figure 8 In the example shown, the value obtained by subtracting the wave number (1 wave) of the second transmission signal 6D output from the control circuit 34 from the wave number (3 waves) of the first transmission signal 6E transmitted to the second electrode 42Y (transmitting electrode) is a positive integer (2 waves).

[0140] In this embodiment, in order to ensure that the first receiving signal 6F can be correctly demodulated even if electromagnetic noise is mixed from the signal line (clock line) used for sending the second sending signal 6D to the signal line used for receiving the first receiving signal 6F received from the first electrode 42X during the receiving period R1 of the first receiving signal 6F, the second sending signal 6D and the first sending signal 6E are sent in advance in the same period D11 so as to be orthogonal to each other.

[0141] That is, as processing when receiving the first received signal 6F, the first received signal 6F received in the receiving period R1 and the internal signal corresponding to the second transmission signal 6D output from the control circuit 34 are multiplied and integrated during a specified period. This allows the first received signal 6F, which is suppressed from mixing with electromagnetic noise caused by the transmission of the second transmission signal 6D, to be extracted (demodulated). In other words, noise that is irrelevant to the characteristics of the first received signal 6F to be detected can be separated, and the decrease in the accuracy of detecting the indicated position of the indicator (finger, electrostatic pen) by the electrostatic capacitance method can be suppressed.

[0142] In addition, in period D11 of period D1, the waveform of the second transmission signal 6C output from the control circuit 34 is orthogonal to the waveform of the first transmission signal 6A transmitted for power-on control of the circular coil. Here, based on the principle of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction, the center frequency of the first transmission signal 6A transmitted for power-on control of the circular coil and the center frequency of the first reception signal 6B received from the electronic pen 23 are the same in the frequency spectrum. Therefore, in the reception period R2 of the first reception signal 6B received from the electronic pen 23, the waveform of the second transmission signal 6C output from the control circuit 34 and the waveform of the first reception signal 6B received from the electronic pen 23 are orthogonal. Figure 8 In the example shown, in the same period D11, the value obtained by subtracting the wave number (1 wave) of the second transmission signal 6C output from the control circuit 34 from the wave number (6 waves) of the first transmission signal 6A sent to control the energization of the annular coil is a positive integer (5 waves).

[0143] In the present embodiment, in order to ensure that the first receiving signal 6B can be correctly demodulated even if electromagnetic noise is mixed from the signal line (clock line) used for sending the second sending signal 6C to the annular coil (X-axis direction annular coil group 22X and Y-axis direction annular coil group 22Y) used for receiving the first receiving signal 6B from the electronic pen 23 during the receiving period R2 of the first receiving signal 6B, the second sending signal 6C and the first sending signal 6A are sent in advance in the same period D11 so as to be orthogonal to each other.

[0144] That is, as processing when receiving the first received signal 6B, the first received signal 6B received in the receiving period R2 and the internal signal corresponding to the second transmission signal 6C output from the control circuit 34 are multiplied and integrated during a specified period. This allows the first received signal 6B, which is suppressed from mixing with electromagnetic noise caused by the transmission of the second transmission signal 6C, to be extracted (demodulated). In other words, noise that is irrelevant to the characteristics of the first received signal 6B to be detected can be separated, and a decrease in the accuracy of detecting the indicated position of the indicator (electronic pen 23) by electromagnetic induction can be suppressed.

[0145] (Variation Example)

[0146] It should be noted that in the above-mentioned embodiment, an example is described in which the value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer when the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal, but the present invention is not limited to this. For example, when the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal, as long as the inner product of the waveform of the first transmission signal and the waveform of the second transmission signal is 0, the value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal can also be 0. In this case, as the first transmission signal, a sine wave, i.e., a sin wave (e.g., sin(2πmx)), can be cited, and as the second transmission signal, a sine wave, i.e., a cos wave (e.g., cos(2πnx), m=n) can be cited. It should be noted that on the first receiving unit side that receives the electromagnetic induction signal, the phase of the signal sent by the electromagnetic induction pen is unclear, so when the first transmission signal and the second transmission signal are waveforms of the same frequency and only the phase is changed (e.g., sin wave and cos wave), it is sometimes difficult to distinguish. Therefore, when the first process is an electromagnetic induction method, it is preferable that a value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal in the same period is a positive or negative integer.

[0147] In addition, in the above-mentioned embodiment, the electronic device 10 may also adopt the In-Cell method. The In-Cell method is a method in which the first electrode 42X or the second electrode 42Y in the second sensor 40 for position detection of the display device 30 and the electrostatic capacitance method is also used as an electrode to which the potential required for driving the display pixel 32 of the display device 30 is supplied (for example, a common electrode of a liquid crystal display, a negative electrode of an organic EL display) is used.

[0148] In addition, the above-mentioned embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be limited by them. That is, the present invention can be implemented in various forms without departing from the gist or main features thereof.

[0149] Description of Reference Numerals

[0150] 10: electronic device, 20: first sensor, 21: wiring substrate, 23: electronic pen, 23L: coil, 23C: capacitor, 22X: X-axis direction annular coil group, 22X1: annular coil, 22Y: Y-axis direction annular coil group, 22Y1: annular coil, 30: display device, 31: display substrate, 32: display pixel, 33: display screen, 34: control circuit, 40: second sensor, 41: transparent substrate, 42X: first electrode, 42X1: signal line, 42Y: second electrode, 42Y1: signal line, 50: control circuit substrate, 60: planar member, 60a: surface, 61: region, 62: frame region, 70: housing, 71: recess, 72: frame region, 100: indicator, 101: Position detection circuit, 200: position detection circuit, 201: selection circuit, 202: oscillator, 203: current driver, 204: transmit-receive switching circuit, 205: receiving amplifier, 206: detection circuit, 207: low-pass filter, 208: sampling and holding circuit, 209: A / D conversion circuit, 210: control circuit, 301: display module, 302: backlight module, 303: gate drive circuit, 304: source drive circuit, 400: position detection circuit, 401: transmitting signal generating circuit, 402: transmitting electrode selection circuit, 404: receiving electrode selection circuit, 405: receiving signal processing circuit, 406 position information output circuit, 410: control circuit, 411: position indication status determination circuit.

Claims

1. An indication position detection device for detecting an indication position of an indication body, wherein: The indicated position detection device includes a first transmitting unit and a second transmitting unit. The first transmitting unit transmits a first transmission signal associated with a first process of detecting an indication position of an indication body, the second transmitting unit transmits a second transmission signal associated with a second process different from the first process, In the same period, the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal to each other.

2. The indicated position detection device according to claim 1, wherein: In the same period, a value obtained by subtracting the wave number of the second transmission signal from the wave number of the first transmission signal is a positive or negative integer.

3. The indicated position detection device according to claim 1, wherein: The first process is a process of detecting the indicated position of the indicator by electromagnetic induction. The second process is a process of detecting the indicated position of the indicator by an electrostatic capacitance method.

4. The indicated position detection device according to claim 1, wherein: A transmission period of the first transmission signal overlaps at least a portion of a transmission period of the second transmission signal.

5. The indicated position detection device according to claim 4, wherein: A start time point and an end time point of a transmission period of the first transmission signal are the same as a start time point and an end time point of a transmission period of the second transmission signal.

6. The indicated position detection device according to claim 1, wherein: The indicated position detection device further comprises a display. The first process is a process of detecting the indicated position of the indicator on the display by electromagnetic induction. The second process is a process of driving the display.

7. The indicated position detection device according to claim 1, wherein: The indicated position detection device further comprises a display. The first process is a process of detecting the indicated position of the indicator on the display by an electrostatic capacitance method. The second process is a process of driving the display.

8. An indication position detection device for detecting an indication position of an indication body, wherein: The indicated position detection device comprises a first transmitting unit, a second transmitting unit, a first receiving unit and a second receiving unit. The first transmitting unit transmits a first transmission signal associated with a first process of detecting an indication position of an indication body, The second transmitting unit transmits a second transmission signal associated with a second process of detecting the indicated position of the indicator, The first receiving unit receives a first reception signal associated with the first processing, The second receiving unit receives a second reception signal associated with the second processing, In the same period, the waveform of the first reception signal and the waveform of the second reception signal are orthogonal to each other.

9. The indicated position detection device according to claim 8, wherein: In the same period, a value obtained by subtracting the wave number of the second received signal from the wave number of the first received signal is a positive or negative integer.

10. The indicated position detection device according to claim 8, wherein: The first receiving unit receives the first reception signal during a transmission period of the second transmission signal.

11. The indicated position detection device according to claim 8, wherein: The second receiving unit receives the second reception signal during a transmission period of the first transmission signal.

12. The indicated position detection device according to claim 8, wherein: A guard interval is provided between a reception period of the first reception signal and a reception period of the second reception signal.

13. A method for detecting an indication position, for detecting an indication position of an indication body, wherein: include: a step of transmitting a first transmission signal associated with a first process of detecting an indication position of an indication body; and the step of transmitting a second transmission signal associated with a second process different from said first process, In the same period, the waveform of the first transmission signal and the waveform of the second transmission signal are orthogonal to each other.

14. A method for detecting an indication position, for detecting an indication position of an indication body, wherein: include: a step of transmitting a first transmission signal associated with a first process of detecting an indication position of an indication body; a step of transmitting a second transmission signal associated with a second process of detecting an indication position of an indication body; The step of receiving a first received signal associated with said first processing; and a step of receiving a second received signal associated with said second processing, In the same period, the waveform of the first reception signal and the waveform of the second reception signal are orthogonal to each other.

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