Position detection method and position detection device

Abstract

To enable position detection of an active pen with relatively high accuracy when the reception level of a downlink signal is high while achieving a relatively high signal-to-noise ratio when the reception level of the downlink signal is low.SOLUTION: A position detection method of the present invention is for detecting the position of an active pen using a sensor comprising multiple sensor electrodes, and involves changing the number of the sensor electrodes used for scanning the active pen depending on pen pressure representing pressure applied to a tip of the active pen.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a pointer position detection method and a sensor controller, and more particularly to a pointer position detection method and a sensor controller for detecting the position of a passive pointer and an active pen. [Background technology]

[0002] There is known an input system that supports both input by an active electrostatic electronic pen (hereinafter referred to as an "active pen") and input by a finger or an auxiliary device that does not transmit signals like a finger (hereinafter collectively referred to as a "passive pointer"). The position of a passive pointer is detected by detecting capacitive coupling that occurs between the tip of the passive pointer and a sensor electrode arranged on the panel surface. Hereinafter, input by an active pen will be referred to as "pen input," and input by a passive pointer will be referred to as "touch input." This type of input system is generally configured to detect the positions of the active pen and the passive pointer on the panel surface in a time-division manner and provide the detected positions to an operating system.

[0003] Patent Document 1 discloses an example of such an input system. The input system described in Patent Document 1 is configured to perform passive pointer position detection for one panel surface in two or more separate steps. This is to enable active pen position detection to be performed at a high detection rate and at equal intervals. Patent Document 1 also discloses a technology for preventing erroneous detection by mutually utilizing the detection results of the passive pointer and the active pen. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6473554 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the inventors of the present application are considering stopping detection of the position of the passive pointer when the active pen is detected, in order to obtain an even higher detection rate for the position of the active pen than the example of the above-mentioned Patent Document 1. Hereinafter, the operating mode of the input system in which the positions of the active pen and the passive pointer are detected in a time-division manner will be referred to as "SPT (Simultaneous Pen Touch) mode," and the operating mode of the input system in which detection of the position of the passive pointer is stopped and only the position of the active pen is detected will be referred to as "exclusive mode."

[0006] However, if the input system is switched to exclusive mode when an active pen is detected, it is obvious that touch input is not possible when the active pen is detected. This means that touch input is not possible when the active pen is very close to the panel surface, which can cause inconvenience to users when performing certain operations, such as when using a pen with their right hand to input data, moving the pen tip slightly away from the panel surface, and then using their left hand to pinch out (a gesture involving gradually increasing the distance between two fingers) to enlarge the display.

[0007] Therefore, one object of the present invention is to provide a pointer position detection method that enables touch input when the active pen is very close to the panel surface, while utilizing the exclusive mode.

[0008] Furthermore, as described in Patent Document 1, if the detection results of the passive pointer and the active pen are used interchangeably, erroneous detection of each can be prevented; however, if the input system is switched to exclusive mode, the passive pointer will no longer be detected, and this prevention of erroneous detection will no longer function.

[0009] Therefore, another object of the present invention is to provide a pointer position detection method that utilizes the exclusive mode while still being able to utilize the erroneous detection prevention function for as long a period as possible. [Means for solving the problem]

[0010] A pointer position detection method according to the present invention is executed by a sensor controller connected to a sensor including a plurality of sensor electrodes, and uses the sensor to detect the position of a passive pointer that does not transmit signals and the position of an active pen that is configured to be able to transmit pen signals from a pen electrode provided at the tip thereof. The pointer position detection method includes an acquisition step of acquiring a pen pressure value that indicates the pressure applied to the pen tip of the active pen, and a control step of controlling the operation mode of the sensor controller in accordance with the pen pressure value, wherein the control step sets the operation mode of the sensor controller to a first operation mode in which the positions of the active pen and the passive pointer on the panel surface are detected in a time-division manner when the pen pressure value indicates that the pen tip is not in contact with the panel surface, and sets the operation mode of the sensor controller to a second operation mode in which the position of the active pen on the panel surface is detected but the position of the passive pointer on the panel surface is not detected when the pen pressure value indicates that the pen tip is in contact with the panel surface.

[0011] The sensor controller according to the present invention is a sensor controller that uses a sensor including multiple sensor electrodes to detect the position of a passive pointer that does not transmit signals and the position of an active pen that is configured to be able to transmit pen signals from a pen electrode provided at the tip thereof, and acquires a pen pressure value that indicates the pressure applied to the pen tip of the active pen, and when the pen pressure value indicates that the pen tip is not in contact with the panel surface, enters a first operating mode in which the positions of the active pen and the passive pointer on the panel surface are detected in a time-division manner, and when the pen pressure value indicates that the pen tip is in contact with the panel surface, enters a second operating mode in which the position of the active pen on the panel surface is detected but the position of the passive pointer on the panel surface is not detected. [Effects of the Invention]

[0012] According to the present invention, the sensor controller operates in the first operating mode (SPT mode) until the tip of the active pen touches the panel surface, so that touch input is possible even when the second operating mode (exclusive mode) is used and the active pen is in close proximity to the panel surface, and the false detection prevention function can be used for as long a period as possible. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing an example of the configuration and usage state of an input system 1 according to an embodiment of the present invention. [Figure 2] 2 is a diagram showing the internal configuration of the tablet terminal 3 shown in FIG. 1. FIG. [Figure 3] 3 is a diagram illustrating an operation mode of the sensor controller 31 shown in FIG. 2. FIG. [Figure 4] 10A is a diagram showing the configuration of an uplink signal US and a downlink signal DS in a global scan GS, and FIG. 10B is a diagram showing the configuration of an uplink signal US and a downlink signal DS in a local scan LS. [Figure 5] 3 is a diagram illustrating the principle of the position detection process of the passive pointer 4 executed by the MCU 40 shown in FIG. 2. FIG. [Figure 6] 3 is a flowchart showing a part of the process performed by the MCU 40 shown in FIG. 2 that is related to the detection of the active pen 2 and the passive pointer 4. FIG. [Figure 7] FIG. 10 is a diagram showing a processing flow of position detection processing in SPT1 mode. [Figure 8] FIG. 10 is a diagram showing a processing flow of position detection processing in SPT2 mode. [Figure 9] FIG. 10 is a diagram showing a processing flow of position detection processing in SPT2 mode revised. [Figure 10] FIG. 10 is a diagram showing a processing flow of position detection processing in exclusive mode. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] FIG. 1 is a diagram showing an example of the configuration and usage state of an input system 1 according to an embodiment of the present invention. The input system 1 is an input system that supports both the pen input and touch input described above, and is configured to include an active pen 2, a tablet terminal 3 having a touch surface 3a (panel surface), and a passive pointer 4. Fingers 4a and 4b shown in FIG. 1 are each an example of the passive pointer 4. In the following description, the active pen 2 and the passive pointer 4 may be collectively referred to as a "pointer."

[0016] FIG. 1 shows an example in which a user holds a pen 2 in his right hand and, with the pen tip slightly raised, performs a pinch-out operation with the fingers 4a and 4b of his left hand. This situation can occur, for example, when a user enlarges an input field displayed on the screen by pinching out and then performs pen input into the input field. When the user slightly raises the pen tip of the pen 2, the distance D between the pen tip and the touch surface 3a (or, more precisely, the sensor 30, described below) is generally shorter than the maximum reach of the downlink signal DS (described below) transmitted by the pen 2. Therefore, since the tablet terminal 3 can detect the active pen 2, if the input system 1 is operating in the above-mentioned exclusive mode, the pinch-out operation is not possible. One of the objectives of the present invention is to eliminate this inconvenience by enabling touch input when the active pen 2 is very close to the touch surface 3a while using the exclusive mode.

[0017] The active pen 2 is an electronic pen that operates by an active electrostatic method. Although not shown, a control unit and a transmission / reception unit are provided inside the active pen 2, and the control unit is configured to be able to transmit and receive signals to and from the tablet terminal 3 via the transmission / reception unit. Hereinafter, a signal transmitted from the tablet terminal 3 to the active pen 2 will be referred to as an uplink signal US, and a signal (pen signal) transmitted from the active pen 2 to the tablet terminal 3 will be referred to as a downlink signal DS.

[0018] A pen electrode is provided at the tip of the active pen 2, and the transmitter / receiver of the active pen 2 receives the uplink signal US and transmits the downlink signal DS via capacitance formed between this pen electrode and a sensor 30 (see FIG. 2, which will be described later) provided in the touch surface 3a of the tablet terminal 3. Note that the pen electrode for receiving the uplink signal US and the pen electrode for transmitting the downlink signal DS may be different or the same.

[0019] The active pen 2 also comprises a pen pressure detection unit that detects the pressure (pen pressure) applied to the pen tip, a side switch state detection unit that detects the on / off state of the side switch provided on the side, a storage unit (memory) that stores a pre-assigned unique ID, and a power supply unit (battery) that supplies operating power for the active pen 2. The control unit of the active pen 2 is configured to be able to control each of these units.

[0020] The tablet terminal 3 is an electronic device that functions both as a liquid crystal display device and as a position detector that detects the position of a pointer on the touch surface 3a. The touch surface 3a is provided on the liquid crystal display screen. Pointers that the tablet terminal 3 can detect include both the active pen 2 and the passive pointer 4 (fingers 4a, 4b) shown in FIG. 1.

[0021] 2 is a diagram showing the internal configuration of the tablet terminal 3. As shown in the figure, the tablet terminal 3 is configured to have a sensor 30, a sensor controller 31, and a host processor 32. Although not shown, the tablet terminal 3 is also configured to have a display.

[0022] The sensor 30 is configured with a plurality of sensor electrodes 30X, 30Y arranged within the touch surface 3a. The tablet terminal 3 is a so-called "in-cell" electronic device, and the plurality of sensor electrodes 30X are also used as display electrodes (for example, common electrodes of a liquid crystal display). However, the present invention is also applicable to electronic devices (non-in-cell electronic devices) in which the plurality of sensor electrodes 30X, 30Y are independent from the display electrodes.

[0023] The sensor controller 31 is an integrated circuit that detects the positions of the active pen 2 and the passive pointer 4 on the touch surface 3a when the multiple sensor electrodes 30X are not being used for pixel driving, i.e., by utilizing intervals between pixel driving operations. The sensor controller 31 is configured to output coordinates indicating the detected position to the host processor 32 each time it detects the position of the active pen 2 or the passive pointer 4.

[0024] The sensor controller 31 is also configured to receive various data from the active pen 2 using intervals between pixel drive operations. The various data received in this manner may include data indicating the writing pressure (writing pressure value) detected by the writing pressure detection unit described above, data indicating the on / off state of the side switch (switch data) acquired by the side switch state detection unit, a unique ID stored in the memory unit, etc. The sensor controller 31 is configured to output the received data to the host processor 32.

[0025] The host processor 32 is the central processing unit of the tablet terminal 3, and by executing programs stored in memory (not shown), it serves to execute the operating system of the tablet terminal 3 and various applications such as drawing software. The drawing software includes a function to generate stroke data based on coordinates sequentially supplied from the sensor controller 31, render the data, and display it on the display, and a function to adjust the rendering results based on data such as the pen pressure value supplied from the sensor controller 31 (for example, a function to adjust the line width according to the pen pressure value).

[0026] FIG. 3 is a diagram showing the operation modes of the sensor controller 31. The sensor controller 31 is configured to operate in any one of the SPT1 mode (third operation mode) shown in FIG. 3(a), the SPT2 mode (first operation mode) shown in FIG. 3(b), and the exclusive mode (second operation mode) shown in FIG. 3(d). However, instead of the SPT2 mode, the modified SPT2 mode shown in FIG. 3(c) may be used. Note that although FIGS. 3(a) to 3(d) illustrate the detection of each pointer as being performed continuously without interruption, as described above, the actual detection is performed using intervals between pixel drive operations, and therefore each detection is performed with appropriate pauses between them. Each operation mode will be described in detail below.

[0027] The SPT1 mode is a mode in which, when the active pen 2 has not yet been detected, a global scan GS of the active pen 2 and position detection of the passive pointer 4 (hereinafter referred to as touch detection T) are executed in a time-division manner. The sensor controller 31 that has entered the SPT1 mode is configured to repeatedly execute an operation unit (UP) consisting of, for example, a touch detection T for 2 milliseconds and a global scan GS for, for example, 3 milliseconds. Note that, as can be seen by comparing Figures 3(a), 3(b), and 3(c), in the SPT1 mode, the frequency of touch detection T is higher than in the SPT2 mode and SPT2 mode modified.

[0028] 4(a) is a diagram showing the configuration of the uplink signal US and downlink signal DS in a global scan GS. In a global scan GS, signals are transmitted and received in the following sequence: first, the sensor controller 31 transmits an uplink signal US, and then, upon receiving this uplink signal US, the active pen 2 transmits a downlink signal DS.

[0029] 4(a), the uplink signal US is a signal that includes a predetermined start bit SB and a command COM that indicates an instruction from the sensor controller 31 to the active pen 2. The command COM transmitted in the global scan GS includes, for example, information about the communication resources that the active pen 2 should use to transmit the downlink signal DS.

[0030] The downlink signal DS during a global scan GS is composed of a position signal, which is a burst signal at a predetermined frequency. As will be described in detail later, the global scan GS is position detection performed by the entire sensor 30, and the sensor controller 31 receives this position signal using all of the multiple sensor electrodes 30X, 30Y arranged on the touch surface 3a, thereby determining the level of the position signal for each position on the touch surface 3a. Based on the results, the sensor controller 31 is configured to detect the position of the active pen 2 and perform pairing with the active pen 2.

[0031] Returning to Figure 3, the SPT2 mode is a mode in which, when the paired active pen 2 is not in contact with the touch surface 3a, the local scan LS of the active pen 2 and the touch detection T are executed in a time-division manner. The sensor controller 31 that has entered the SPT2 mode is configured to repeatedly execute an operation unit (UP) consisting of, for example, a touch detection T for 2 milliseconds, a local scan LS for 3 milliseconds, and another local scan LS for 3 milliseconds.

[0032] 4(b) is a diagram showing the configuration of the uplink signal US and downlink signal DS in the local scan LS. In the local scan LS, signals are transmitted and received in the following procedure: first, the sensor controller 31 transmits an uplink signal US, and then, upon receiving this uplink signal US, the active pen 2 transmits a downlink signal DS. The command COM transmitted in the local scan LS includes, for example, information identifying one of the one or more active pens 2 currently paired, and information specifying the data to be transmitted by the identified active pen 2.

[0033] The downlink signal DS during local scan LS is composed of a position signal, which is a burst signal of a predetermined frequency, and a data signal containing various data. Because the data signal includes the data signal, the transmission duration of the position signal is shorter than during global scan GS. Examples of data included in the data signal include the pen pressure value, switch data, and unique ID described above. The control unit of the active pen 2 is configured to place data specified by the command COM in the uplink signal US into the data signal.

[0034] The local scan LS is a position detection performed using only a portion of the sensor 30. The sensor controller 31 receives the position signal using only a predetermined number of sensor electrodes 30X, 30Y located near the previously detected position among the multiple sensor electrodes 30X, 30Y arranged on the touch surface 3a, and calculates the level of the position signal for each position near the previously detected position. The sensor controller 31 then detects the position of the active pen 2 based on the results. The sensor controller 31 also obtains the data transmitted by the active pen 2 by decoding the received data signal.

[0035] In this embodiment, a relatively small number (four in this example) and a relatively large number (eight in this example) of sensor electrodes 30X and 30Y are used to receive position signals during local scan LS. In Fig. 3, these numbers are shown in parentheses after "LS."

[0036] As can be seen from FIG. 3(b), in SPT2 mode, position signals are received using a relatively small number of sensor electrodes 30X, 30Y. When using a relatively small number of sensor electrodes 30X, 30Y in this manner, the reception time per electrode can be relatively long, resulting in a relatively high signal-to-noise ratio. Therefore, since reception is possible even when the reception level of the downlink signal DS is low, this mode is suitable for when the active pen 2 is not in contact with the touch surface 3a (i.e., when hovering).

[0037] In contrast, when a relatively large number of sensor electrodes 30X, 30Y are used, as in the exclusive mode described below (see FIG. 3(d)), position signals can be received over a wider area, making it possible to detect the position of the active pen 2 with relatively high accuracy. However, because only a relatively low signal-to-noise ratio can be obtained, position signals can be received using such a relatively large number of sensor electrodes 30X, 30Y only when the active pen 2 is in contact with the touch surface 3a and the sensor controller 31 can receive the downlink signal DS at a high level.

[0038] Returning to Figure 3, the revised SPT2 mode is an improvement over the SPT2 mode so that local scans LS can be performed at equal intervals, and is configured to perform touch detection T for one panel surface in two separate operations. Specifically, the touch surface 3a can be divided into halves, and touch detection T can be performed alternately. The sensor controller 31 that has entered the revised SPT2 mode is configured to repeatedly execute one operation unit (UP), which is, for example, touch detection T / 2 (1 / 2 touch detection T) for 1 millisecond and a local scan LS (4) for 3 milliseconds.

[0039] The exclusive mode is a mode in which, when a detected active pen 2 is in contact with the touch surface 3a, touch detection T is not performed and only a local scan LS of the active pen 2 is executed. The sensor controller 31 that has entered the exclusive mode is configured to repeatedly execute a local scan LS of, for example, 3 milliseconds as one operation unit (UP). As described above, reception of position signals in the exclusive mode is executed using a relatively large number of sensor electrodes 30X, 30Y (specifically, eight). The reason for this is as described above.

[0040] Referring again to FIG. 2, the configurations of the sensor 30, the sensor controller 31, and the host processor 32 will be described in more detail below.

[0041] The sensor 30 has a configuration in which a plurality of sensor electrodes 30X and 30Y are arranged in a matrix, each extending in the Y direction and arranged at equal intervals in the X direction perpendicular to the Y direction, and a plurality of sensor electrodes 30Y are arranged in the X direction and arranged at equal intervals in the Y direction. Note that, although an example is shown in which the sensor electrodes 30X and 30Y are both formed of linear conductors, the sensor electrodes 30X and 30Y may also be formed of conductors of other shapes. For example, one of the sensor electrodes 30X and 30Y may be formed of a plurality of rectangular conductors arranged two-dimensionally so that the two-dimensional coordinates of the active pen 2 can be detected.

[0042] As shown in FIG. 2, the sensor controller 31 includes an MCU 40, a logic unit 41, transmission units 42 and 43, a reception unit 44, and a selection unit 45.

[0043] The MCU 40 and logic unit 41 are control units that control the transmission and reception operations of the sensor controller 31 by controlling the transmission units 42 and 43, the reception unit 44, and the selection unit 45. More specifically, the MCU 40 is a microprocessor that has internal memory (ROM and RAM) and operates by executing programs stored in this memory. The operation timing of the MCU 40 is controlled by a timing signal supplied from the host processor 32. In addition to the control operation of the logic unit 41, the MCU 40 performs the following operations: supplying a pixel drive voltage Vcom to a selection unit 45; controlling a transmission unit 42 to output a finger detection signal FDS; supplying a command COM indicating the content of an instruction to the active pen 2 to a transmission unit 43; detecting the positions of the active pen 2 and the passive pointer 4 (specifically, coordinates x and y indicating the position on the touch surface 3a) based on a digital signal supplied from a reception unit 44; obtaining data Res (e.g., the above-mentioned writing pressure value, switch data, or unique ID) transmitted by the active pen 2 by decoding the digital signal supplied from the reception unit 44; determining the contact state of the active pen 2 with respect to the touch surface 3a based on the writing pressure value included in the data Res; and entering one of the operation modes shown in FIG. 3 depending on the result of this determination. The logic unit 41 has a function of outputting control signals ctrl_t1 to ctrl_t4 and ctrl_r under the control of the MCU 40.

[0044] The transmitter 42 is a circuit that generates a finger detection signal FDS under the control of the MCU 40 and supplies it to each sensor electrode 30X via a selector 45.

[0045] 5 is a diagram illustrating the principle of the position detection process of the passive pointer 4 executed by the MCU 40. For simplicity, only four sensor electrodes 30X are shown in the diagram, but in reality, more sensor electrodes 30X are arranged. In the following description, the number of sensor electrodes 30X is assumed to be K.

[0046] As shown in the upper right part of FIG. 5, the finger detection signal FDS is, for example, K signals s1 to s2 each consisting of K pulses represented by "1" or "-1". K The signals s1 to s K Each nth (n=1~K) pulse is a pulse group p n and one pulse group p n The pulses constituting the signal are input in parallel to the sensor electrodes 30X from the transmitter 42 shown in FIG.

[0047] Returning to Fig. 2, the transmitter 43 is a circuit that generates an uplink signal US under the control of the MCU 40 and the logic unit 41 and supplies it to the selector 45, and as shown in the figure, is configured to include a pattern supplier 50, a switch 51, a code string holder 52, a spreading processor 53, and a transmission guard unit 54. Of these, the pattern supplier 50 in particular will be described as being included in the transmitter 43 in this embodiment, but it may also be included in the MCU 40.

[0048] The pattern supplying unit 50 holds a start bit SB placed at the beginning of the uplink signal US, and is configured to output the held start bit SB in accordance with an instruction of a control signal ctrl_t1 supplied from the logic unit 41.

[0049] The switch 51 has the function of selecting either the pattern supplying unit 50 or the MCU 40 based on a control signal ctrl_t2 supplied from the logic unit 41, and supplying the output of the selected one to the diffusion processing unit 53. When the switch 51 selects the pattern supplying unit 50, a start bit SB is supplied to the diffusion processing unit 53. On the other hand, when the switch 51 selects the MCU 40, a command COM is supplied to the diffusion processing unit 53.

[0050] The code sequence holding unit 52 has a function of generating and holding a spreading code of a predetermined chip length having autocorrelation characteristics, based on a control signal ctrl_t3 supplied from the logic unit 41. The spreading code held by the code sequence holding unit 52 is supplied to a spreading processing unit 53.

[0051] The spreading processing unit 53 has a function of acquiring a transmission chip sequence of a predetermined chip length by modulating the spreading code held by the code sequence holding unit 52 based on the value (start bit SB or command COM) supplied via the switch 51. The spreading processing unit 53 supplies the acquired transmission chip sequence to the selection unit 45 via the transmission guard unit 54.

[0052] The transmission guard unit 54 has the function of inserting a guard period (a period in which neither transmission nor reception is performed) required to switch between transmission and reception operations between the transmission period of the uplink signal US and the reception period of the downlink signal DS based on the control signal ctrl_t4 supplied from the logic unit 41.

[0053] The selection unit 45 includes switches 58x and 58y and conductor selection circuits 59x and 59y.

[0054] The switch 58y is a switch element configured to connect its common terminal to either the T terminal or the R terminal. The common terminal of the switch 58y is connected to the conductor selection circuit 59y, the T terminal is connected to the output terminal of the transmitter 43, and the R terminal is connected to the input terminal of the receiver 44. The switch 58x is a switch element configured to connect its common terminal to either the T1 terminal, the T2 terminal, the D terminal, or the R terminal. Of these, the T2 terminal is actually a set of terminals equal to the number of sensor electrodes 30X. The common terminal of the switch 58x is connected to the conductor selection circuit 59x, the T1 terminal is connected to the output terminal of the transmitter 43, the T2 terminal is connected to the output terminal of the transmitter 42, the D terminal is connected to the output terminal of the MCU 40 that outputs the pixel drive voltage Vcom, and the R terminal is connected to the input terminal of the receiver 44.

[0055] The conductor selection circuit 59x is a switch element for selectively connecting the plurality of sensor electrodes 30X to a common terminal of the switch 58x. The conductor selection circuit 59x is configured to be able to simultaneously connect some or all of the plurality of sensor electrodes 30X to the common terminal of the switch 58x. Furthermore, when the T2 terminal and the common terminal are connected in the switch 58x, the conductor selection circuit 59x connects the plurality of terminals constituting the T2 terminal to the plurality of sensor electrodes 30X in a one-to-one relationship.

[0056] The conductor selection circuit 59y is a switch element for selectively connecting the plurality of sensor electrodes 30Y to the common terminal of the switch 58y. The conductor selection circuit 59y is also configured to be able to simultaneously connect some or all of the plurality of sensor electrodes 30Y to the common terminal of the switch 58y.

[0057] The selection unit 45 is supplied with four control signals sTRx, sTRy, selX, and selY from the logic unit 41. Specifically, the control signal sTRx is supplied to the switch 58x, the control signal sTRy is supplied to the switch 58y, the control signal selX is supplied to the conductor selection circuit 59x, and the control signal selY is supplied to the conductor selection circuit 59y. The logic unit 41 controls the selection unit 45 using these control signals sTRx, sTRy, selX, and selY, thereby realizing the transmission of the uplink signal US or the finger detection signal FDS, the application of the pixel drive voltage Vcom, and the reception of the downlink signal DS or the finger detection signal FDS.

[0058] More specifically, at the timing of transmitting the uplink signal US, the logic unit 41 controls the selection unit 45 so that all of the plurality of sensor electrodes 30Y are simultaneously connected to the transmission unit 43. As a result, the uplink signal US is simultaneously transmitted from all of the plurality of sensor electrodes 30Y, and the active pen 2 can receive the uplink signal US wherever it is on the touch surface 3a.

[0059] Next, at the timing of receiving the above-mentioned position signal in the downlink signal DS, the logic unit 41 performs different processes depending on whether it is performing the above-mentioned global scan GS or the above-mentioned local scan LS. Specifically, when performing the global scan GS, the logic unit 41 first selects all of the sensor electrodes 30X, 30Y one by one in sequence and controls the selector 45 so that the selected sensor electrodes 30X, 30Y are connected to the receiver 44. As a result, a number of position signals equal to the number of sensor electrodes 30X, 30Y are sequentially supplied to the receiver 44. When performing the local scan LS, the MCU 40 first selects the number of sensor electrodes 30X, 30Y (four or eight) according to the currently entered operation mode from among the sensor electrodes 30X, 30Y in the vicinity of the previously detected position. The logic unit 41 sequentially selects the predetermined number of sensor electrodes 30X, 30Y selected in this manner one by one at time intervals corresponding to the number of selected sensor electrodes 30X, 30Y, and controls the selection unit 45 so that the selected sensor electrodes 30X, 30Y are connected to the receiving unit 44. As a result, position signals equal in number to the selected sensor electrodes 30X, 30Y are sequentially supplied to the receiving unit 44.

[0060] The MCU 40 is configured to detect the position of the active pen 2 based on the level of the position signal thus supplied to the receiving unit 44. Specifically, the MCU 40 determines the level of the position signal at each intersection of the multiple sensor electrodes 30X, 30Y based on a digital signal (described later) supplied from the receiving unit 44. Then, based on each determined level, it detects the position of the active pen 2. Specifically, it determines an area within the touch surface 3a where the level of the position signal is equal to or greater than a predetermined value, and detects, for example, the center position of that area as the position of the active pen 2.

[0061] Next, at the timing to receive the above-mentioned data signal from the downlink signal DS, the MCU 40 first selects one of the multiple sensor electrodes 30X, 30Y that is closest to the position of the active pen 2 detected based on the immediately preceding position signal. The logic unit 41 controls the selection unit 45 so that the sensor electrode 30X, 30Y selected in this manner is connected to the receiving unit 44. As a result, the data signal transmitted by the active pen 2 is supplied to the receiving unit 44.

[0062] Next, at the timing to transmit the finger detection signal FDS, the logic unit 41, together with the MCU 40, selects one sensor electrode 30Y and outputs the pulse groups p1 to p2 shown in FIG. K to the transmitter 42 in turn to each of the sensor electrodes 30X. This operation is repeated for each sensor electrode 30Y. Specifically, the logic unit 41 first controls the selector 45 so that the multiple terminals constituting the T2 terminal of the switch 58x are connected one-to-one to the multiple sensor electrodes 30X. Then, while maintaining this state, the logic unit 41 controls the selector 45 to select the multiple sensor electrodes 30Y one by one and connect the selected sensor electrode 30Y to the receiver 44.

[0063] Furthermore, while one sensor electrode 30Y is selected, the MCU 40 outputs pulse groups p1 to p K The MCU 40 sequentially reads out one pulse group at a time from the memory, and supplies the K pulses constituting the read pulse group to the transmitter 42 each time the pulses are read out. The transmitter 42 inputs the K pulses thus supplied in parallel to the K sensor electrodes 30X. As a result of this control, the level of the digital signal supplied from the receiver 44 reflects changes in capacitance formed at the intersections between the selected sensor electrode 30Y and each sensor electrode 30X. The MCU 40 is therefore configured to detect the position of the passive pointer 4 based on the level of the digital signal supplied from the receiver 44.

[0064] 5 again, the position detection process of the passive pointer 4 executed by the MCU 40 will be described in more detail. In the following, the description will be given assuming that the number of sensor electrodes 30X is four (i.e., K=4), but the same applies to the case where the number of sensor electrodes 30X is three or less or five or more.

[0065] When the number of sensor electrodes 30X is four, signals s1 to s K Each of the signals s1 and s4 is composed of four pulses represented by "1" or "-1." Specifically, as shown in Figure 5, signal s1 is composed of "1,1,1,1," signal s2 is composed of "1,1,-1,-1," signal s3 is composed of "1,-1,-1,1," and signal s4 is composed of "1-1,1,-1."

[0066] The MCU 40 functionally includes a shift register 40a and a correlator 40b. The shift register 40a is a FIFO-type memory unit configured to store the same number of data (i.e., K data) as the number of sensor electrodes 30X. When new data is stored in the shift register 40a, the data stored K times previously is erased. As described above, the MCU 40 and logic unit 41 select one sensor electrode 30Y and cause the transmitter 42 to sequentially input pulse groups p1 to p4 to each sensor electrode 30X. This operation is repeated for each sensor electrode 30Y. As a result, four levels L1 to L4 corresponding to the pulse groups p1 to p4 appear sequentially on the selected sensor electrode 30Y. The MCU 40 sequentially acquires the levels L1 to L4 appearing on the sensor electrode 30Y via the receiver 44 and stores them in the shift register 40a each time.

[0067] The specific contents of the levels L1 to L4 will be described in detail by taking the case where the sensor electrode 30Y1 shown in Fig. 5 is selected as an example. In the following description, the capacitances formed between the sensor electrode 30Y1 and each of the four sensor electrodes 30X1 to 30X4 will be referred to as C 11 ~C 41 Let's say.

[0068] First, the level L1 stored in the shift register 40a corresponding to the pulse group p1 is expressed as a capacitance vector (C 11 ,C 21 ,C 31 ,C 41 ) and the vector (1,1,1,1) representing the pulse group p1. This inner product is C 11 +C 21 +C 31 +C 41 Similarly, the level L2 stored in the shift register 40a corresponding to the pulse group p2 is calculated as a vector of capacitances (C 11 ,C 21 ,C 31 ,C 41 ) and the vector (1,1,-1,-1) representing the pulse group p1, and 11 +C 21 -C 31 -C 41 The level L3 stored in the shift register 40a corresponding to the pulse group p3 is calculated as follows: 11 ,C 21 ,C 31 ,C 41 ) and the vector (1,-1,-1,1) representing the pulse group p3, which is C 11 -C 21 -C 31 +C 41 The level L4 stored in the shift register 40a corresponding to the pulse group p4 is calculated as follows: 11 ,C 21 ,C 31 ,C 41 ) and the vector (1,-1,1,-1) representing the pulse group p4, and 11 -C 21 +C 31 -C 41 It is calculated as follows.

[0069] The MCU 40 uses the correlator 40b to sequentially calculate correlation values ​​T1 to T4 between the levels L1 to L4 stored in the shift register 40a and each of the four pulse groups p1 to p4. The specific contents of the correlation values ​​T1 to T4 calculated in this way are respectively 4C 11 ,4C 21 ,4C 31 ,4C 41 That is, the correlation values ​​T1 to T4 reflect the change in capacitance formed at the intersection of the sensor electrodes 30X1 to 30X4 and the sensor electrode 30Y1, respectively. Therefore, the MCU 40 can detect the position of the passive pointer 4 by referring to the correlation values ​​T1 to T4 calculated for each sensor electrode 30Y. Specifically, an area on the touch surface 3a where the change in capacitance is equal to or greater than a predetermined value is determined, and the center position of that area is detected as the position of the passive pointer 4, for example. Note that if there are multiple, separated areas on the touch surface 3a where the change in capacitance is equal to or greater than a predetermined value, the MCU 40 can detect each of these areas as the position of the passive pointer 4.

[0070] 2, the logic unit 41 controls the switch 58x to connect the D terminal to the common terminal when applying the pixel drive voltage Vcom, thereby supplying the pixel drive voltage Vcom to each of the multiple sensor electrodes 30X, enabling pixel drive operation to be performed.

[0071] The receiving unit 44 is a circuit that receives the downlink signal DS transmitted by the active pen 2 or the finger detection signal FDS transmitted by the transmitting unit 42, based on the control signal ctrl_r from the logic unit 41. Specifically, it is configured to include an amplifier circuit 55, a detection circuit 56, and an analog-to-digital (AD) converter 57.

[0072] The amplifier circuit 55 amplifies and outputs the downlink signal DS or the finger detection signal FDS supplied from the selector 45. The detector circuit 56 is a circuit that generates a voltage corresponding to the level of the output signal of the amplifier circuit 55. The AD converter 57 is a circuit that generates a digital signal by sampling the voltage output from the detector circuit 56 at predetermined time intervals. The digital signal output by the AD converter 57 is supplied to the MCU 40.

[0073] Based on the digital signals thus supplied, the MCU 40 detects the positions (coordinates x, y) of the passive pointer 4 and the active pen 2, and acquires the data Res transmitted by the active pen 2. Specifically, first, regarding the position of the passive pointer 4, the MCU 40 generates pulse groups p1 to p2 for each sensor electrode 30Y based on the digital signals supplied. K Levels L1 to L K Obtain levels L1~L K The method for detecting the position of the passive pointer 4 from the digital signal is as described above with reference to Fig. 5. Next, with regard to the position of the active pen 2, the MCU 40 determines the level of the position signal at each intersection of the plurality of sensor electrodes 30X, 30Y based on the supplied digital signal, as described above, and detects the position of the active pen 2 based on each determined level. Finally, with regard to the data Res, the MCU 40 obtains the data Res by decoding the digital signal supplied from the receiving unit 44. The MCU 40 is configured to output the position (coordinates x, y) and data Res thus detected to the host processor 32.

[0074] The MCU 40 is also configured to determine the contact state of the active pen 2 with the touch surface 3a based on the writing pressure value included in the acquired data Res, and when it determines that the active pen 2 has newly come into contact with the touch surface 3a (i.e., when the writing pressure changes from 0 to a positive value), output pen-down information IN-PROXY to the host processor 32, and when it determines that the active pen 2 has been released from the touch surface 3a (i.e., when the writing pressure changes from a positive value to 0), output pen-up information OUT-PROXY to the host processor 32. The pen-down information IN-PROXY and pen-up information OUT-PROXY thus output are used by the host processor 32 to recognize the start and end of a stroke.

[0075] The MCU 40 further selects one of the above-mentioned SPT1 mode, SPT2 mode (or modified SPT2 mode), and exclusive mode depending on whether the downlink signal DS is received and whether the pen pressure value included in the acquired data Res indicates that the pen tip is in contact with the touch surface, and enters the selected operation mode.Then, the logic unit 41 and other components are controlled depending on the entered operation mode.The processing performed by the MCU 40 in this regard will be described in detail below with reference to the flow charts shown in Figures 6 to 10.

[0076] 6 is a flow diagram showing the part of the process performed by the MCU 40 that is related to the detection of the active pen 2 and the passive pointer 4. As shown in the figure, the MCU 40 first enters the SPT1 mode (step S1), and then repeatedly executes the processes of steps S3 to S9 (step S2).

[0077] The MCU 40, which has started the processing of steps S3 to S9, first performs a position detection process (step S3). The details of this position detection process differ depending on the operation mode that the MCU 40 has entered. The details of the position detection process in each operation mode will be explained later with reference to FIGS. 7 to 10. The MCU 40 performs a process (control step) to control the operation mode of the sensor controller 31 by executing steps S4 to S9 depending on the result of this position detection process (specifically, whether or not the active pen 2 is detected and the writing pressure value received from the active pen 2).

[0078] More specifically, the MCU 40 first determines whether or not the active pen 2 has been detected during the position detection process (step S4, determination step). This determination can be made depending on whether or not the downlink signal DS has been detected during the position detection process. That is, if the downlink signal DS has been detected even once, it can be determined that the active pen 2 has been detected, and if the downlink signal DS has not been detected even once, it can be determined that the active pen 2 has not been detected.

[0079] If the MCU 40 determines in step S4 that the active pen 2 has not been detected, it cancels the pairing if it has already been paired with the active pen 2 in step S17 (see FIG. 7) described later (step S6), enters the SPT1 mode (step S7), and returns to step S3. As a result, in the next position detection process, a global scan GS of the active pen 2 is performed in a time-division manner with the position detection of the passive pointer 4.

[0080] The MCU 40, which has determined that the pressure has been detected in step S4, then determines whether the writing pressure value received from the active pen 2 is equal to 0 or greater than 0 (step S5). Note that a writing pressure value equal to 0 indicates that the pen tip of the active pen 2 is not in contact with the touch surface 3a, and a writing pressure value greater than 0 indicates that the pen tip of the active pen 2 is in contact with the touch surface 3a.

[0081] If the MCU 40 determines in step S5 that the "pen pressure value is equal to 0," it enters the SPT2 mode (or modified SPT2 mode) (step S8) and returns to step S3. As a result, in the next position detection process, the local scan LS of the active pen 2 is performed in a time-division manner with the position detection of the passive pointer 4. Also, as shown in Figures 3(b) and 3(c), in this case, the position signal is received using four sensor electrodes 30X, 30Y, making it possible to obtain a relatively high signal-to-noise ratio.

[0082] On the other hand, if the MCU 40 determines in step S5 that the "pen pressure value is greater than 0," it enters the exclusive mode (step S9) and returns to step S3. As a result, in the next position detection process, the position of the passive pointer 4 is not detected, and only the local scan LS of the active pen 2 is performed. This makes it possible to relatively increase the detection rate (detection frequency) of the position of the active pen 2. Furthermore, as shown in FIG. 3(d), in this case, position signals are received using eight sensor electrodes 30X, 30Y, making it possible to detect the position of the active pen 2 with relatively high accuracy.

[0083] Next, the position detection process in each operation mode will be described in detail with reference to FIGS.

[0084] 7 is a diagram showing the processing flow of the position detection processing in the SPT1 mode. As shown in the figure, the MCU 40 first detects the position of the passive pointer 4 by performing touch detection (position detection of the passive pointer 4; the same applies hereinafter) (step S10).

[0085] Here, in step S10, due to capacitive coupling occurring between the pen electrode provided at the tip of the active pen 2 and the sensor electrodes 30X, 30Y, the position of the active pen 2 may be detected as the position of the passive pointer 4. Furthermore, if the user places their hand on the touch surface 3a, a position unintended by the user may be detected as the position of the passive pointer 4.

[0086] Therefore, instead of automatically determining all of the one or more positions detected in step S10 as touch positions, the MCU 40 determines one or more touch positions from the one or more positions detected in step S10 based on the result of the position detection of the active pen 2 executed immediately before and the area of ​​the region on the touch surface 3a where the change in capacitance is equal to or greater than a predetermined value (step S11). This prevents erroneous detection as described above. The MCU 40 then outputs coordinates (x, y) indicating the determined touch positions to the host processor 32 shown in FIG. 2 (step S12).

[0087] Next, the MCU 40 transmits an uplink signal US (step S13) and determines whether a downlink signal DS has been detected in response thereto (step S14). If a downlink signal DS has not been detected, the position detection process ends. On the other hand, if a downlink signal DS has been detected, the MCU 40 receives the position signal transmitted by the active pen 2 using each of the sensor electrodes 30X and 30Y, and detects the position of the pen based on the results (step S15).

[0088] Here, in step S15, the downlink signal DS transmitted by the active pen 2 is also transmitted from the hand holding the active pen 2, and as a result, the position of the hand holding the active pen 2 may be detected as the position of the active pen 2. Also, a current path is formed that runs from the pen electrode provided at the tip of the active pen 2 through the sensor electrodes 30X and 30Y, into the arm opposite the hand holding the active pen 2, and then returns to the active pen 2 via the human body, and as a result, the downlink signal DS is detected below this arm, and a position that is not in contact with either the active pen 2 or the passive pointer 4 may be detected as the position of the active pen 2 (ghost position).

[0089] Therefore, the MCU 40 does not automatically determine all of the one or more positions detected in step S15 as the pen position, but rather determines one or more pen positions from the one or more positions detected in step S15 based on the result of the position detection of the passive pointer 4 executed immediately before (step S16). This prevents erroneous detection as described above. The MCU 40 then executes pairing with the active pen 2 that transmitted the position signal (step S17), and outputs the coordinates (x, y) indicating the determined pen position to the host processor 32 shown in Fig. 2 (step S18), thereby completing the position detection process.

[0090] 8 is a diagram showing the processing flow of the position detection processing in SPT2 mode. As shown in the diagram, the MCU 40 first executes the above-mentioned steps S10 to S12 to output the coordinates (x, y) indicating the touch position to the host processor 32 shown in FIG.

[0091] Next, the MCU 40 assigns 1 to a variable M (step S20), and determines whether the variable M is 2 or less (step S21). If the variable M is 2 or less, the MCU 40 transmits an uplink signal US (step S22), and determines whether a downlink signal DS has been detected in response thereto (step S23). If the variable M is not 2 or less, the position detection process ends.

[0092] If it is determined in step S23 that the downlink signal DS has not been detected, the MCU 40 adds 1 to the variable M and returns to step S21. On the other hand, if it is determined that the downlink signal DS has been detected, the MCU 40 selects four sensor electrodes 30X, 30Y based on the previous pen position, receives the position signal transmitted by the active pen 2 using the selected sensor electrodes 30X, 30Y, and detects the pen position based on the result (step S24). Next, the MCU 40 selects one sensor electrode 30X, 30Y based on the previous pen position, and receives the data signal transmitted by the active pen 2 using the selected sensor electrode 30X, 30Y (step S25). By receiving this data signal, the MCU 40 acquires data such as the writing pressure value transmitted by the active pen 2 (acquisition step).

[0093] Next, the MCU 40 determines one or more pen positions from the one or more positions detected in step S24 based on the result of the position detection of the passive pointer 4 executed immediately before, in the same manner as in step S16 shown in Fig. 7 (step S26). Then, the MCU 40 outputs the coordinates (x, y) indicating the determined pen positions together with the data included in the received data signal to the host processor 32 shown in Fig. 2 (step S27). Thereafter, the MCU 40 adds 1 to the variable M and returns to step S21.

[0094] 9 is a diagram showing the processing flow of the position detection processing in the revised SPT2 mode. As shown in the figure, the MCU 40 first executes 1 / N of the touch detection processing (step S30). The 1 / N of the touch detection processing is one processing in the case where touch detection for one panel surface is executed in N divided times. For example, it is conceivable that the touch surface 3a is divided into N areas, and touch detection is executed for these N areas in order.

[0095] After executing 1 / N of the touch detection process, the MCU 40 records partial detection data indicating the results in a memory (not shown) (step S31), and further generates overall detection data by combining it with the past N-1 partial detection data (step S32). Based on the generated overall detection data, the MCU 40 detects the positions of one or more passive pointers 4 (step S33), and determines one or more touch positions from the one or more positions detected in step S33 based on the result of the position detection of the active pen 2 executed immediately before and the area of ​​the region on the touch surface 3a where the change in capacitance is equal to or greater than a predetermined value (step S34). Having determined the touch positions in this way, the MCU 40 outputs coordinates (x, y) indicating the determined touch positions to the host processor 32 shown in FIG. 2 (step S35).

[0096] Next, the MCU 40 executes steps S22 to S27 described with reference to FIG. 8 to output the coordinates (x, y) indicating the pen position and the data contained in the received data signal to the host processor 32 shown in FIG. 2, and ends the position detection process.

[0097] 10 is a diagram showing the processing flow of the position detection processing in the exclusive mode. In this case, the MCU 40 transmits an uplink signal US (step S40) without performing processing to detect the position of the passive pointer 4. Then, it determines whether a downlink signal DS has been detected in response thereto (step S41), and if it determines that a downlink signal DS has not been detected, it ends the position detection processing.

[0098] On the other hand, if it is determined that the downlink signal DS has been detected, the MCU 40 selects eight sensor electrodes 30X, 30Y based on the previous pen position, receives the position signal transmitted by the active pen 2 using the selected sensor electrodes 30X, 30Y, and detects the pen position based on the result (step S42). Next, the MCU 40 selects one sensor electrode 30X, 30Y based on the previous pen position, and receives the data signal transmitted by the active pen 2 using the selected sensor electrode 30X, 30Y (step S43).

[0099] Next, the MCU 40 outputs the coordinates (x, y) indicating the position detected in step S42 and the data included in the data signal received in step S43 to the host processor 32 shown in Fig. 2 (step S44), and ends the position detection process. Note that in exclusive mode, processing such as step S26 shown in Figs. 8 and 9 is not performed, and the position detected in step S42 is output as is as the pen position. This is because the position of the passive pointer 4 is not detected.

[0100] As described above, according to the input system 1 of this embodiment, the sensor controller 31 operates in the SPT1 mode or SPT2 mode (or modified SPT2 mode) in which the sensor controller 31 also detects the position of the passive pointer 4 until the pen tip of the active pen 2 comes into contact with the touch surface 3a, so that touch input is possible with the active pen 2 in close proximity to the touch surface 3a while using the exclusive mode in which detection of the passive pointer 4 is not performed. Furthermore, since the period of operation in the exclusive mode can be minimized, it becomes possible to use the erroneous detection prevention function (specifically, the process of step S16 shown in FIG. 7 and the process of step S26 shown in FIGS. 8 and 9) for as long a period as possible.

[0101] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention.

[0102] For example, in the above embodiment, if the MCU 40 does not detect a downlink signal DS even once in a single position detection process, the MCU 40 immediately cancels the pairing and enters the SPT1 mode (steps S6 and S7 in Figure 6), but it may also be configured to cancel the pairing and enter the SPT1 mode only after the MCU 40 has not detected a downlink signal DS a predetermined number of times or for a predetermined period of time.

[0103] Furthermore, in the above embodiment, the MCU 40 entered the exclusive mode when the pen pressure value became greater than 0 (step S9 in FIG. 6), but it is also possible to start detecting a gesture operation (e.g., a pinch-out operation) using the passive pointer 4 while in the SPT2 mode, and not enter the exclusive mode even if the pen pressure value becomes greater than 0 while the detected gesture operation continues, but to enter the exclusive mode when the detected gesture operation ends. In this way, even if the user accidentally brings the pen tip into contact with the touch surface 3a during a pinch-out operation, for example, it is possible to continue touch input until the pinch-out operation is completed. [Explanation of symbols]

[0104] 1 Input System 2 Active Pen 3. Tablet devices 3a Touch Surface 4 Passive Pointers 4a,4b fingers 30 sensors 30X, 30Y sensor electrodes 31 Sensor Controller 32 host processor 40a Shift register 40b Correlator 41 Logic Section 42,43 Transmitter 44 Receiving unit 45 Selection section 50 Pattern supply unit 51 Switch 52 Code string holding section 53 Diffusion processing section 54 Transmission guard section 55 Amplification circuit 56 Detector circuit 57 Analog-to-Digital Converter 58x,58y switch 59x, 59y Conductor selection circuit COM Commands ctrl_t1~ctrl_t4,ctrl_r control signals DS downlink signal FDS Finger detection signal GS Global Scan IN-PROXY pen-down information LS Local Scan OUT-PROXY Pen-up Information SB start bit sTRx, sTRy, selX, selY control signals T Touch detection US uplink signal Vcom Pixel drive voltage

Claims

1. 1. A position detection method for detecting a position of an active pen using a sensor including a plurality of sensor electrodes, comprising: changing the number of the sensor electrodes used for scanning the active pen in accordance with a writing pressure value indicating the pressure applied to the pen tip of the active pen; Location detection methods.

2. When the writing pressure value indicates that the active pen is in contact with a panel surface, scanning the active pen using a first number of the sensor electrodes; when the writing pressure value indicates that the active pen is not in contact with the panel surface, scanning the active pen using a second number of the sensor electrodes that is smaller than the first number; The position detection method according to claim 1 .

3. entering a first operation mode in which detection of the active pen and the passive pointer is performed in a time-division manner when the writing pressure value indicates that the active pen is not in contact with the panel surface; entering a second operational mode in which the active pen is detected but the passive pointer is not detected when the writing pressure value indicates that the active pen is in contact with the panel surface; In the first operation mode, the active pen is scanned using a smaller number of the sensor electrodes than in the second operation mode. The position detection method according to claim 1 .

4. scanning the active pen includes a process of sequentially receiving a position signal of a predetermined duration transmitted by the active pen at each of the plurality of sensor electrodes used for scanning the active pen; The fewer the number of the sensor electrodes used for scanning the active pen, the longer the time for receiving the position signal per one of the sensor electrodes. The position detection method according to any one of claims 1 to 3.

5. A position detection device that detects the position of an active pen using a sensor including a plurality of sensor electrodes, changing the number of the sensor electrodes used for scanning the active pen in accordance with a writing pressure value indicating the pressure applied to the pen tip of the active pen; Position detection device.

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