JP7159411B2 - Sensor controller, computer implemented method and electronics - Google Patents

Description

The present invention relates to a stylus and a sensor controller, and more particularly to a stylus and a sensor controller that constitute a position detection system in which the sensor controller detects a stylus based on burst signals transmitted from the stylus.

A conventional stylus transmits a data signal including data such as pen pressure and stylus ID following a burst signal for causing the sensor controller to detect itself and its position. The burst signal is a signal having a predetermined waveform known in advance between the stylus and the sensor controller (for example, an unmodulated signal with a predetermined frequency). A data signal, on the other hand, is a signal modulated by data to be transmitted. FIG. 7 of Patent Document 1 discloses an example of a stylus that performs such signal transmission.

When the sensor controller is not detecting the stylus, the sensor controller tries to detect the burst signal by sequentially using all of the multiple electrodes arranged side by side on the touch surface. When a burst signal is detected as a result, an attempt is made to detect a data signal using only some of the electrodes located near the electrode that detected the burst signal.

International Publication No. 2015/111159

However, the conventional sensor controller has a problem that it may fail to detect the burst signal even though it reaches the touch surface, especially when the stylus is not yet in contact with the touch surface (while hovering). there were. This is because there is a distance between the stylus and the touch surface during hovering, so the amplitude of the burst signal detected by the sensor controller becomes small and a sufficient S/N ratio cannot be obtained. On the other hand, it is conceivable to lengthen the detection operation time per electrode as one means for obtaining a sufficient S/N ratio even during hovering. It becomes difficult to detect burst signals at range. This is because the transmission of the burst signal ends before all the electrodes within the range are scanned once.

Also, even when the pen-down operation is performed and the stylus and the sensor controller approach a distance at which a sufficient S/N ratio can be obtained, if the stylus transmits a data signal instead of a burst signal at that timing, Stylus detection by the sensor controller may fail.

Therefore, one of the objects of the present invention is to ensure that burst signals can be detected over a wide range within the touch surface in order to identify the position of an undetected stylus, while preventing failure of burst signal detection by the sensor controller. It is an object of the present invention to provide a stylus and a sensor controller capable of reducing noise.

A stylus according to one aspect of the present invention is a stylus capable of bi-directional communication with a sensor controller, comprising: a receiving unit for receiving an uplink signal transmitted by the sensor controller; a control unit for determining whether to continuously transmit a signal having a predetermined waveform over a second period of time or continuously transmit a signal having a predetermined waveform over a first period of time longer than the second period of time; a transmitting unit that continuously transmits the signal of the predetermined waveform over the first time or the second time based on the determination result of the unit.

A stylus according to another aspect of the present invention is a stylus capable of bi-directional communication with a sensor controller, comprising: a receiver for receiving an uplink signal transmitted by the sensor controller; a control unit for determining the state of the sensor controller by the uplink signal; While continuously transmitting a signal of a predetermined pattern known in advance between the sensor controller for a predetermined time, when the uplink signal indicates that the sensor controller has already derived the position of the stylus, the signal of the predetermined pattern is not continuously transmitted for the predetermined period of time, and a data signal that varies depending on the operating state of the stylus is transmitted.

A sensor controller according to one aspect of the present invention is a sensor controller configured to be able to derive the position of a stylus by detecting a signal transmitted from the stylus, and detects whether the stylus has been detected or not. a determining step for determining, in response to determination that the stylus has been detected by the determining step, instructing the stylus to continuously transmit the signal having the predetermined waveform for a second period of time; transmitting a second uplink signal; and, in response to the determining step determining that the stylus is undetected, sending a signal having a predetermined waveform to the stylus for a first period of time longer than the second time. transmitting a first uplink signal indicating continuous transmission over time.

A sensor controller according to another aspect of the present invention includes M first electrodes each extending in a first direction and N electrodes each extending in a second direction different from the first direction. a sensor controller connected to a matrix electrode comprising second electrodes for providing a predetermined signal to each of said M first electrodes and each of said N second electrodes; and a finger touch detection step of performing finger touch detection based on the predetermined signal detected in and using at least a portion of the M first electrodes and at least a portion of the N second electrodes, a full range scanning step for detecting a stylus of detection and deriving position coordinates of the stylus; a number of said first electrodes less than the number of said first electrodes used in said full range scanning step; and a sector scanning step of deriving the already detected position coordinates of the stylus by using a number of the second electrodes smaller than the number of the second electrodes used in the scanning step.

According to the present invention, the sensor controller can expect the stylus to transmit a long burst signal that lasts longer than a normal burst signal in stylus undetected conditions where the stylus is likely hovering. Become. Therefore, it is possible to detect the burst signal by scanning more electrodes within the period during which the long burst signal is continuously transmitted, while making the detection operation time per electrode longer than when receiving the normal burst signal. , it is possible to reduce the possibility of burst signal detection failure by the sensor controller while ensuring a state in which burst signals can be detected over a wide range within the touch surface.

1A and 1B are diagrams showing the configuration of an electronic device 3 according to an embodiment of the present invention, in which FIG. The operation of the electronic device 3 is shown. It is a figure which shows the structure of the electronic device 3 by embodiment of this invention. 4 is a diagram showing configurations of a long burst signal, a burst signal, and a data signal transmitted by the stylus 2 according to the embodiment of the invention; FIG. FIG. 4 is a diagram showing a signal transmission/reception sequence between the stylus 2 and the sensor controller 31 when the stylus 2 is above the uplink detection height AH. (b) shows a case where the sensor controller 31 requests transmission of a long burst signal. FIG. 4 is a diagram showing a signal transmission/reception sequence between the stylus 2 and the sensor controller 31 when the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2; ) is when the sensor controller 31 transmits the pen activation signal, (b) is when the sensor controller 31 receives the long burst signal transmitted by the stylus 2 using the linear electrode 30Y, and (c) is when the stylus 2 Each shows a case where the sensor controller 31 receives the transmitted long burst signal using the linear electrode 30X. FIG. 10 is a diagram showing a sequence of signal transmission and reception between the stylus 2 and the sensor controller 31 after the stylus 2 is inside the sensing range SR and the sensor controller 31 has identified the position of the stylus 2, and burst signals from the stylus 2; and when the data signal is transmitted. FIG. 4 is a diagram for explaining the operation of the sensor controller 31 according to the embodiment of the present invention, in which (a) shows the first half of the full range scan, (b) shows the latter half of the full range scan, and (c) shows the sector scan. ing. It is a figure which shows the structure of the stylus 2 by embodiment of this invention. 4 is a processing flow diagram showing the overall operation of the sensor controller 31 according to the embodiment of the present invention; FIG. 4 is a processing flow diagram showing stylus detection processing performed by the sensor controller 31 according to the embodiment of the present invention; FIG. FIG. 11 is a processing flow diagram showing the operation of the stylus 2 corresponding to FIG. 10; FIG. 4 is a diagram showing a configuration of a stylus 2 according to a first modified example of the embodiment of the invention; FIG. 10 is a processing flow diagram showing the operation of the stylus 2 according to the second modified example of the embodiment of the invention; FIG. 12 is a processing flow diagram showing the operation of the sensor controller 31 according to the third modified example of the embodiment of the invention; FIG. 10 is a diagram showing a long burst signal transmitted by a stylus 2 according to a fourth modified example of the embodiment of the invention; FIG. 12 is a processing flow diagram showing the operation of the stylus 2 according to the fifth modification of the embodiment of the invention; It is a diagram for explaining the specific position exclusion processing according to the sixth modification of the embodiment of the present invention, (a) is the finger touch area detected by the finger touch detection processing, (b) is the Each shows the position of the stylus 2 derived by the stylus detection process executed immediately after the finger touch detection process. FIG. 20 is a processing flow diagram showing the operation of the sensor controller 31 according to the sixth modification of the embodiment of the invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of an electronic device 3 according to this embodiment. The electronic device 3 is, for example, a computer having a touch surface such as a tablet terminal, and includes a sensor 30 and a sensor controller 31 as shown in the figure.

The sensor 30 is a matrix electrode including M linear electrodes 30X (first electrodes) and N (N<M) linear electrodes 30Y (second electrodes) arranged inside the touch surface. Consists of In a specific example, M=72 and N=46. The M linear electrodes 30X are arranged to extend at regular intervals in a first direction parallel to the touch surface. Further, the N linear electrodes 30Y are arranged so as to extend at equal intervals in a second direction parallel to the touch surface and perpendicular to the first direction. Each linear electrode 30X and each linear electrode 30Y are individually connected to the sensor controller 31 .

The sensor controller 31 uses the sensor 30 to detect a touch by the finger F (including deriving the position coordinates of the finger F within the touch surface) and detect the stylus 2 (determine the position coordinates of the stylus 2 within the touch surface). (including derivation) in a time-sharing manner.

FIG. 1A shows the operation of the electronic device 3 when detecting a touch with a finger F. FIG. As shown in the figure, when detecting a touch by a finger F, the sensor controller 31 sequentially supplies a predetermined signal (hereinafter referred to as "finger detection signal") to each of the plurality of linear electrodes 30Y. At the same time, by sequentially scanning the potential of each of the plurality of linear electrodes 30X, a finger detection signal arriving at each linear electrode 30X through the intersection with the linear electrode 30Y is detected. The amplitude of the finger detection signal detected in this manner is smaller when the finger F is approaching the intersection through which the finger detection signal passes than when it is not. This is because part of the current flowing on the linear electrodes 30X and 30Y flows toward the human body through capacitive coupling generated between the finger F and the linear electrodes 30X and 30Y. The sensor controller 31 detects a touch by the finger F by detecting such a change in amplitude.

FIG. 1(b) shows the basic operation of the electronic device 3 when the stylus 2 is detected. As shown in the figure, when detecting the stylus 2, the sensor controller 31 basically operates by sequentially using the plurality of linear electrodes 30X and the plurality of linear electrodes 30Y as receiving electrodes. 2 (hereinafter referred to as "downlink signal"). Then, the stylus 2 is detected based on the detection result. In an actual operation, only part of the linear electrodes 30X and 30Y may be used to detect the stylus 2, but this point will be described later.

In order for the sensor controller 31 to detect the stylus 2 , the stylus 2 must be close enough to the touch surface of the electronic device 3 that the sensor controller 31 can receive the downlink signal. The illustrated sensing range SR schematically shows the range in which the sensor controller 31 can receive the downlink signal. The sensor controller 31 receives a downlink signal when the stylus 2 enters this sensing range SR, thereby enabling the stylus 2 to be detected. The movement of the stylus 2 moving from outside to inside the sensing range SR is hereinafter referred to as "pen down". Pen-down is usually performed by a user's operation of bringing the stylus 2 closer to the touch surface of the electronic device 3 . A state in which the stylus 2 has entered the sensing range SR but is not yet in contact with the touch surface is referred to as "during hovering". When the stylus 2 goes through a pen-down state and enters a hover state, the sensor controller 31 attempts to detect the stylus 2 by detecting a downlink signal. There is a distance, and depending on the distance, it becomes difficult to secure a sufficient S/N ratio, and as a result, detection of the stylus 2 may fail. Even if the stylus 2 is within the sensing range SR, the sensor controller 31 may fail to detect the stylus 2 while the stylus 2 is transmitting data signals instead of burst signals. One of the objects of the present invention is to avoid such failures.

Here, even when the stylus 2 is outside the sensing range SR, there are cases where the signal sent by the sensor controller 31 to the stylus 2 (hereinafter referred to as an "uplink signal") can be received. This is because some uplink signals (such as a pen activation signal and a command signal indicating a transmission instruction for a long burst signal, which will be described later) are applied to the entire touch surface (one or both of all the linear electrodes 30X and all the linear electrodes 30Y). This is because it is transmitted using The illustrated uplink detection height AH indicates the height limit (distance from the touch surface) at which the stylus 2 can receive these uplink signals. The uplink detection height AH is at a position higher than the upper limit of the sensing range SR (a position farther from the touch surface).

FIG. 2 is a diagram showing the configuration of the electronic device 3 according to this embodiment. The plurality of linear electrodes 30X and the plurality of linear electrodes 30Y that constitute the sensor 30 are configured to capacitively couple with the stylus 2 and the finger F. As shown in FIG. When the finger F approaches the sensor 30, part of the current flowing from the sensor controller 31 to the linear electrode 30Y is absorbed by the finger F through this capacitive coupling. This reduces the amplitude of the finger detection signal detected by the linear electrodes 30X as described above, so that the sensor controller 31 can detect a touch by the finger F. FIG. Moreover, the sensor 30 is configured to be able to bidirectionally transmit and receive signals to and from the stylus 2 via the capacitive coupling.

The sensor controller 31 includes a transmission section 60, a selection section 40, a reception section 50, a logic section 70, and an MCU 80, as shown in FIG.

The transmission unit 60 is a circuit that generates a finger detection signal at the timing of detecting a touch with the finger F, and generates an uplink signal at the timing of detecting the stylus 2 . The uplink signal includes a pen activation signal for informing the stylus 2 of the existence of the sensor controller 31 and a command signal indicating an instruction (command) to the stylus 2 .

In the transmitting section 60 of FIG. 2, only functional blocks related to generation of uplink signals are shown in detail. This functional block includes a pattern supply section 61 , a switch 62 , a spreading processing section 63 , a code string storage section 64 and a transmission guard section 65 . Among them, the pattern supply unit 61 in particular is described as being included in the transmitting unit 60 in this embodiment, but may be included in the MCU 80 .

The pen activation signal is composed of repetition of a predetermined detection pattern c1 and a predetermined delimiter pattern STP arranged at the end.

The detection pattern c1 is a pattern of symbol values used by the stylus 2 to detect the presence of the sensor controller 31, and is made known to the stylus 2 in advance (before the stylus 2 detects the sensor controller 31). there is A symbol is a unit of information used for modulation (a unit of information represented by a transmission signal) in transmission processing, and a unit of information obtained by demodulating one symbol, which is a reception signal, in reception processing. Symbol values are divided into values that are converted into bit strings (hereinafter referred to as "bit string corresponding values") and values that are not converted into bit strings by the stylus 2 that receives the symbols (hereinafter referred to as "bit string non-corresponding values"). can contain. In a specific example, the detection pattern c1 is composed of a pattern "PM" which is a combination of two types of bit string non-corresponding values "P" and "M".

The delimiter pattern STP is a symbol value pattern for notifying the stylus 2 of the end of the repetition period of the detection pattern c1, and is composed of a pattern that does not appear during the repetition of the detection pattern c1. The delimiter pattern STP is also made known to the stylus 2 in advance (before the stylus 2 detects the sensor controller 31). For example, when the detection pattern c1 is composed of the combination "PM" of the two bit string non-corresponding values "P" and "M" as described above, the delimiter pattern STP is the bit string non-corresponding value "P" twice. It can be configured by a continuous pattern "PP". The configurations of the delimiter pattern STP and the detection pattern c1 may be reversed so that the delimiter pattern is composed of "PM" and the detection pattern c1 is composed of "PP".

The pattern supply unit 61 holds the detection pattern c1 and the delimiter pattern STP, and is configured to output them in a predetermined order according to the instruction of the control signal ctrl_t1 supplied from the logic unit 70 . Specifically, the detection pattern c1 is continuously and repeatedly output during a predetermined continuous transmission period, and the delimiting pattern STP is output immediately after the continuous transmission period ends. This implements the transmission of the pen activation signal. Note that the delimiter pattern STP may be output at the beginning of a command signal (described later) indicating an instruction to transmit a long burst signal.

The switch 62 has a function of selecting either the pattern supply unit 61 or the MCU 80 based on the control signal ctrl_t2 supplied from the logic unit 70 and supplying the output of the selected one to the diffusion processing unit 63 . When the switch 62 selects the pattern supply unit 61 , the pattern supply unit 61 supplies the detection pattern c<b>1 or the delimiter pattern STP to the diffusion processing unit 63 . On the other hand, when the switch 62 selects the MCU 80 , the control information c 2 is supplied from the MCU 80 to the spread processing section 63 .

The control information c2 is information indicating an instruction (command) to the stylus 2 and is generated by the MCU80. The command signal described above is composed of this control information c2. The control information c2 includes a symbol value (for example, 0 to 15) associated with a variable-length bit string, and is not shared with the stylus 2 in advance. different.

The code string holding unit 64 has a function of generating and holding a spread code PN of a predetermined chip length having autocorrelation characteristics based on the control signal ctrl_t3 supplied from the logic unit 70 . The spreading code PN held by the code string holding unit 64 is supplied to the spreading processing unit 63 .

The spreading processing unit 63 modulates the spreading code PN held by the code string holding unit 64 based on the symbol value (detection pattern c1, delimiter pattern STP, or control information c2) supplied via the switch 62. has a function of obtaining a transmission chip sequence of a predetermined chip length. The spreading processing unit 63 is configured to supply the acquired transmission chip sequence to the transmission guard unit 65 .

Based on the control signal ctrl_t4 supplied from the logic unit 70, the transmission guard unit 65 sets the guard necessary for switching between the transmission operation and the reception operation between the transmission period of the uplink signal and the reception period of the downlink signal. It has a function to insert a period (a period during which neither transmission nor reception is performed).

The receiving section 50 is a circuit for receiving the finger detection signal transmitted by the transmitting section 60 or the downlink signal transmitted by the stylus 2 based on the control signal ctrl_r of the logic section 70 . Specifically, it includes an amplifier circuit 51 , a detection circuit 52 , and an analog-to-digital (AD) converter 53 .

The amplifier circuit 51 amplifies the signal (finger detection signal or downlink signal) supplied from the selector 40 and outputs the amplified signal. The detection circuit 52 is a circuit that generates a voltage corresponding to the level of the output signal of the amplification circuit 51 . The AD converter 53 is a circuit that generates a digital signal by sampling the voltage output from the detection circuit 52 at predetermined time intervals. A digital signal output from the AD converter 53 is supplied to the MCU 80 .

The selection unit 40 includes switches 44x and 44y and conductor selection circuits 41x and 41y.

Each of the switches 44x and 44y is a 1-circuit, 2-contact switch element configured such that a common terminal is connected to either one of the T terminal and the R terminal. The switch 44x has a common terminal connected to the conductor selection circuit 41x, a T terminal connected to the output terminal of the transmitter section 60, and an R terminal connected to the input terminal of the receiver section 50. FIG. The switch 44 y has a common terminal connected to the conductor selection circuit 41 y , a T terminal connected to the output terminal of the transmitter 60 , and an R terminal connected to the input terminal of the receiver 50 .

The conductor selection circuit 41x is a switch element for selectively connecting the M linear electrodes 30X to the common terminal of the switch 44x. The conductor selection circuit 41x is configured to be able to simultaneously connect some or all of the M linear electrodes 30X to the common terminal of the switch 44x.

The conductor selection circuit 41y is a switch element for selectively connecting the N linear electrodes 30Y to the common terminal of the switch 44y. The conductor selection circuit 41y is also configured to be able to simultaneously connect some or all of the N linear electrodes 30Y to the common terminal of the switch 44y.

The selector 40 is supplied with four control signals sTRx, sTRy, selX, and selY from the logic unit 70 . Specifically, the control signal sTRx is supplied to the switch 44x, the control signal sTRy to the switch 44y, the control signal selX to the conductor selection circuit 41x, and the control signal selY to the conductor selection circuit 41y. The logic unit 70 controls the selection unit 40 using these control signals sTRx, sTRy, selX, and selY to transmit and receive finger detection signals and transmit uplink signals including pen activation signals and command signals. and reception of downlink signals. Control of the selection unit 40 by the logic unit 70 will be described later in more detail.

The logic unit 70 and the MCU 80 are control units that control transmission/reception operations of the sensor controller 31 by controlling the transmission unit 60 , the reception unit 50 and the selection unit 40 . Specifically, the MCU 80 is a microprocessor that has an internal ROM and RAM and operates based on a predetermined program. On the other hand, the logic section 70 is configured to output each control signal described above based on the control of the MCU 80 . The MCU 80 also derives coordinate data x, y, etc. indicating the position of the finger F or the stylus 2 based on the digital signal supplied from the AD converter 53, and outputs the data to the system controller of the electronic device 3; When the digital signal supplied from the AD converter 53 indicates a data signal, the data Res represented by the digital signal is obtained and output to the system controller of the electronic device 3. Configured.

The control of the selector 40 by the logic unit 70 will be specifically described below.

First, in the logic section 70 for transmitting and receiving the finger detection signal, the N linear electrodes 30Y are sequentially connected to the output terminal of the transmitting section 60, and the M linear electrodes 30X are sequentially connected to the receiving section 50. The selector 40 is controlled using the control signals sTRx, sTRy, selX, and selY so as to be connected to the input terminal. As a result, as shown in FIG. 1, the finger detection signal is sequentially supplied to each of the N linear electrodes 30Y, and each linear electrode 30X passes through the intersection with the linear electrode 30Y. Since the receiving unit 50 can detect the finger detection signal that has arrived at , the detection of the touch by the finger F is realized.

When transmitting an uplink signal and receiving a downlink signal, the logic unit 70 performs different processing depending on the detection state of the stylus 2 and the type of downlink signal. Below, the types of downlink signals and the sequence of signal transmission/reception between the stylus 2 and the sensor controller 31 will be described first, and then the logic for transmitting uplink signals and receiving downlink signals. The operation of unit 70 will be described in detail.

FIG. 3 is a diagram showing types of downlink signals transmitted by the stylus 2 according to an embodiment of the invention. As shown in the figure, downlink signals include long burst signals, burst signals, and data signals. The long burst signal is a signal obtained by continuously transmitting a signal having a predetermined waveform, which is a signal having a predetermined pattern known in advance between the stylus 2 and the sensor controller 31, for a predetermined time T1 (first time). be. A burst signal is a signal obtained by continuously transmitting a signal having the predetermined waveform for a predetermined time T2 (second time) shorter than the time T1. The data signal is a data signal obtained by modulating the signal of the predetermined waveform with data, and is transmitted following the burst signal within a time corresponding to the difference T1-T2 between time T2 and time T1. A predetermined gap signal (not shown) is inserted at the beginning of the burst signal to indicate a break from the burst signal. The type of downlink signal transmitted by the stylus 2 is selected according to the command signal transmitted by the sensor controller 31 .

4 to 6 show the sequence of signal transmission and reception between the stylus 2 and the sensor controller 31. FIG. 4 shows the case where the stylus 2 is above the uplink detection height AH, FIG. 6 shows a stage in which the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2, while the stylus 2 is inside the sensing range SR and the sensor controller 31 , respectively, after specifying the position of the stylus 2 . Each case will be described below in order.

<When the stylus 2 is above the uplink detection height AH>
FIG. 4(a) shows when the sensor controller 31 transmits the pen activation signal, and FIG. 4(b) shows when the sensor controller 31 requests transmission of the long burst signal.

First, as shown in FIG. 4A, the sensor controller 31 transmits a pen activation signal over a period of time T (=t1-t0) from time t0 to time t1. This transmission is performed when the sensor controller 31 has not detected the stylus 2 yet. The pen activation signal is a signal including repetition of the detection pattern c1 and the trailing delimiter pattern STP, as described above. The stylus 2 intermittently detects the detection pattern c1 by intermittently detecting the symbols (“P” and “M” in the above example) forming the detection pattern c1. If it is above the link detection height AH, the detection pattern c1 cannot be detected even by this detection operation. Therefore, the stylus 2 simply repeats the detection operation of the detection pattern c1.

After transmitting the pen activation signal, the sensor controller 31 starts transmitting a command signal (denoted as “CMD” in FIGS. 4 to 6) at time t2 after time t1, as shown in FIG. 4B. . The time required to transmit the command signal is T0, which is shorter than the time T described above. At the stage where the stylus 2 has not yet been detected, the sensor controller 31 transmits a command signal indicating an instruction to transmit a long burst signal. However, since the stylus 2 located above the uplink detection height AH cannot receive this command signal, it does not transmit a long burst signal in response to the command signal, and simply repeats the detection operation of the detection pattern c1. .

After transmitting a command signal indicating an instruction to transmit a long burst signal, the sensor controller 31 performs a long burst signal detection operation. This detection operation corresponds to the first half of a full-range scan, which will be described later, and is performed by sequentially using the N linear electrodes 30Y. Details of the full range scan will be described later. Since the stylus 2 does not transmit the long burst signal here, the sensor controller 31 naturally does not detect the long burst signal. The time that can be used for detecting the long burst signal is time T1 (=T−T0) corresponding to the difference between time T and time T0. , the long burst signal detection operation is temporarily completed at time t3 before time t4 (=t2+T) when time T1 elapses. Therefore, the sensor controller 31 in the case where the long burst signal is not detected during this detection operation enters a sleep state from time t3 to time t4. Thereby, the power consumption of the sensor controller 31 is reduced. After time t4, transmission of the pen activation signal is repeated.

<Stage where the stylus 2 is inside the sensing range SR and the sensor controller 31 has not yet specified the position of the stylus 2>
5A shows the time when the sensor controller 31 transmits the pen activation signal, and FIG. 5B shows the case where the sensor controller 31 receives the long burst signal transmitted by the stylus 2 using the linear electrode 30Y. 5(c) shows the case where the sensor controller 31 receives the long burst signal transmitted by the stylus 2 using the linear electrode 30X.

When the pen-down operation (time t6) is performed as shown in FIG. 5(a), the stylus 2 can detect the detection pattern c1 by the subsequent operation for detecting the detection pattern c1 (time t7). After detecting the detection pattern c1 in this way, the stylus 2 continues the detection operation until the break pattern STP is detected. Then, when the delimiter pattern STP is detected, it synchronizes with the sensor controller 31 based on the detection time. Specifically, this synchronization is performed by creating a transmission/reception schedule, which will be described later.

Note that in FIG. 5A, the pen down operation is performed at time t6 between time t5 when transmission of the pen activation signal is started and time t8 (=t5+T) when transmission of the pen activation signal is completed, and at time t8 An example is shown in which the stylus 2 detects the detection pattern c1 at time t7, which is the time before the detection pattern c1. Even at time t6′) shown in b), the same processing is executed with only a slight delay in the detection timing of the detection pattern c1 by the stylus 2 .

Subsequently, as shown in FIG. 5B, when the sensor controller 31 starts transmitting a command signal indicating an instruction to transmit a long burst signal at time t9 after time t8, the stylus 2 receives this command signal and A long burst signal is continuously transmitted over time T1 up to t10 (=t9+T). The sensor controller 31 detects the stylus 2 by detecting the long burst signal thus transmitted.

Specifically, first, as shown in FIG. 5B, the N linear electrodes 30Y are sequentially used to perform a long burst signal detection operation (the first half of full range scanning, which will be described later). At this time, since the long burst signal is detected by any one or more linear electrodes 30Y, the sensor controller 31 stores the detection intensity of the long burst signal in each linear electrode 30Y. Next, as shown in FIG. 5C, at time t11 after time t10, the sensor controller 31 restarts transmission of the command signal indicating the transmission instruction of the long burst signal. Do it again. This detection operation is performed by sequentially using the M linear electrodes 30X until time t12 (=t11+T) (the second half of the full range scan described later). By this detection operation, a long burst signal is detected by any one or more of the linear electrodes 30X, so the sensor controller 31 stores the detected intensity of the long burst signal in each linear electrode 30X. Then, the position coordinates of the stylus 2 on the touch surface are derived based on the previously stored detection intensity of the long burst signal at each linear electrode 30Y and the currently stored detection intensity of the long burst signal at each linear electrode 30X.

<After the stylus 2 is inside the sensing range SR and the sensor controller 31 identifies the position of the stylus 2>
FIG. 6 shows when the stylus 2 transmits burst signals and data signals. As shown in the figure, after specifying the position of the stylus 2, the sensor controller 31 starts transmitting a command signal indicating a data transmission instruction at time t13 thereafter. The stylus 2 receiving this first continuously transmits a burst signal over time T2. The sensor controller 31 detects this burst signal and derives the position coordinates of the stylus 2 based on the detected burst signal. The burst signal detection operation sequentially detects only those of the M linear electrodes 30X and the N linear electrodes 30Y that are shown to be near the stylus 2 by the position coordinates of the stylus 2 derived immediately before. (sector scan to be described later). The stylus 2 transmits a data signal containing the instructed data following the burst signal. The sensor controller 31 acquires the data transmitted by the stylus 2 by receiving and decoding this data signal. Data signal reception is performed using only one linear electrode 30X or linear electrode 30Y corresponding to the position coordinates of the stylus 2 derived immediately before.

Returning to FIG. 2, the operation of the logic section 70 when detecting the stylus 2 and performing two-way communication with the stylus 2 will be described in detail.

When transmitting a command signal indicating an instruction to transmit a pen activation signal and a long burst signal (Figs. The selector 40 is controlled so that all of the linear electrodes 30X or all of the N linear electrodes 30Y or both of them are used simultaneously. Specifically, the control signals sTRx, sTRy, selX, and selY are set so that the output terminal of the transmission unit 60 is connected to one or both of the M linear electrodes 30X and the N linear electrodes 30Y at the same time. is used to control the selector 40 . As a result, the command signal indicating the transmission instruction of the pen activation signal and the long burst signal is transmitted over the entire touch surface. , can receive these signals.

When the long burst signal is received at the stage where the stylus 2 has not yet been detected (FIGS. 4B and 5B), the logic section 70 is also shown in FIGS. 4B and 5B. , the selector 40 is controlled to sequentially use the N linear electrodes 30Y. Specifically, the selection unit 40 is controlled using the control signals sTRy and selY so that the N linear electrodes 30Y are sequentially connected to the input terminal of the reception unit 50 . This enables the sensor controller 31 to receive the long burst signal transmitted by the stylus 2 wherever the stylus 2 is within the sensing range SR shown in FIG. 1, thereby detecting the stylus 2 .

FIG. 7A is a diagram for explaining the operation of the sensor controller 31 in this case. As shown in the figure, the sensor controller 31 in this case sequentially scans the N linear electrodes 30Y. The reason why the M linear electrodes 30X are not scanned at this stage is that the entire surface of the sensor 30 can be scanned using only the N linear electrodes 30Y. This is to lengthen the scanning time of

After detecting the stylus 2 by receiving the long burst signal, when receiving the long burst signal at a stage where the position coordinates of the stylus 2 have not yet been derived (FIG. 5(c)), the logic unit 70 performs ), the selector 40 is controlled to sequentially use the M linear electrodes 30X. Specifically, the selector 40 is controlled using the control signals sTRx and selX so that the M linear electrodes 30X are sequentially connected to the input terminal of the receiver 50 . The sensor controller 31 derives the position coordinates of the stylus 2 on the touch surface as described above, based on the result of this control and the result of detection of the long burst signal by the N linear electrodes 30Y previously performed. do.

FIG. 7B is a diagram for explaining the operation of the sensor controller 31 in this case. As shown in the figure, the sensor controller 31 in this case sequentially scans the M linear electrodes 30X. In this specification, a scan (first half) that sequentially uses the N linear electrodes 30Y shown in FIG. 7A and a scan that sequentially uses the M linear electrodes 30X shown in FIG. second half) are collectively referred to as a “whole range scan” (first scan).

When the command signal is transmitted after deriving the position coordinates of the stylus 2 (FIG. 6), the logic unit 70 selects one of the M linear electrodes 30X and the N linear electrodes 30Y near the stylus 2. The selector 40 is controlled to use only those in the . Specifically, for example, if the stylus 2 is positioned at the intersection of the j+5-th linear electrode 30X and the i+5-th linear electrode 30Y, for example, a range of five lines on each side from there, that is, the j-th to The selection unit uses the control signals sTRx, sTRy, selX, and selY so that the j+10th linear electrode 30X and the i-th to i+10th linear electrodes 30Y are simultaneously connected to the output terminal of the transmission unit 60. control 40; As a result, the command signal can be transmitted using only the linear electrode near the stylus 2, so power consumption required for transmission of the command signal can be reduced. Also, if the command signals are supplied equally to the hands placed on the touch surface, the ground potential supplied to the stylus 2 may increase, and as a result, the detection accuracy of the uplink signal by the stylus 2 may decrease. However, by transmitting the command signal using only the linear electrodes near the stylus 2 as described above, the possibility that the command signal is equally supplied to the hands decreases, so the uplink signal by the stylus 2 It becomes possible to prevent the deterioration of the detection accuracy of

After deriving the position coordinates of the stylus 2, the logic unit 70 receives normal burst signals other than long burst signals (FIG. 6). The selector 40 is controlled so that only those near the stylus 2 are sequentially used. Specifically, for example, if the stylus 2 is positioned at the intersection of the j+5th linear electrode 30X and the i+5th linear electrode 30Y, for example, as shown in FIG. That is, the control signals sTRx, sTRy, selX, selY is used to control the selector 40 . As a result, the reception time per linear electrode can be lengthened, so that the burst signal can be received more reliably.

FIG. 7(c) is a diagram for explaining the operation of the sensor controller 31 in this case. Also in this example, the stylus 2 is positioned at the intersection of the j+5th linear electrode 30X and the i+5th linear electrode 30Y. The sensor controller 31 according to this example sequentially controls only 11 linear electrodes 30X from the j-th to the j+10th and 11 linear electrodes 30Y from the i-th to the i+10th among the M×N linear electrodes. Scanning is performed, and the position coordinates of the stylus 2 are derived based on the result. Hereinafter, a scan for re-deriving (updating) the once derived position coordinates of the stylus 2 by using both a portion of the M linear electrodes 30X and a portion of the N linear electrodes 30Y will be referred to as a "sector scan". scan” (second scan).

When receiving a data signal (FIG. 6), the logic unit 70 selects to use only one linear electrode 30X or linear electrode 30Y corresponding to the position of the stylus 2 derived by the previous burst signal. control unit 40; Specifically, the selection unit 40 is operated using the control signals sTRx, sTRy, selX, and selY so that the one linear electrode 30X or the linear electrode 30Y is connected to the input terminal of the receiving unit 50. Control. This allows the data signal transmission time (=T1−T2) to be fully utilized for transmitting data from the stylus 2 to the sensor controller 31 .

The operation of the logic unit 70 when detecting the stylus 2 and performing two-way communication with the stylus 2 has been described above.

FIG. 8 is a block diagram showing functional blocks of the stylus 2 according to this embodiment. As shown in the figure, the stylus 2 includes an electrode 21 , a writing pressure detection sensor 23 and a signal processing section 24 .

The electrode 21 is a conductive member provided in the vicinity of the tip of the core of the stylus 2, and serves as an antenna for transmitting downlink signals. It also acts as an antenna for receiving signals.

The writing pressure detection sensor 23 is a pressure sensor for detecting pressure (writing pressure) applied to the tip of the core of the stylus 2 .

The signal processing unit 24 receives an uplink signal from the sensor controller 31 via the electrode 21, performs processing according to the content of the signal, generates a downlink signal to be transmitted to the sensor controller 31, and controls the electrode 21. It has a function of transmitting to the sensor controller 31 via the sensor controller 31 . Specifically, it functionally includes a switching unit 76 , a receiving unit 71 , a transmitting unit 75 , and a control unit 90 . Each of these functional blocks will be described in turn below.

The switching unit 76 is a 1-circuit, 2-contact switching element configured such that the common terminal is connected to either one of the T terminal and the R terminal. The common terminal of the switching section 76 is connected to the electrode 21 , the T terminal is connected to the output terminal of the transmitting section 75 , and the R terminal is connected to the input terminal of the receiving section 71 . The state of the switching section 76 is controlled by a control signal SWC from the control section 90 . When receiving an uplink signal from the sensor controller 31, the control unit 90 controls the switching unit 76 by the control signal SWC so that the R terminal and the common terminal are connected. Further, when transmitting a downlink signal to the sensor controller 31, the switching unit 76 is controlled by the control signal SWC so that the T terminal and the common terminal are connected. In the initial state, that is, until the stylus 2 detects the detection pattern c1 described above, the control unit 90 fixes the switching unit 76 to a state in which the R terminal and the common terminal are connected, and then controls the consumption of the stylus 2. Go to sleep to save power.

The receiving unit 71 is a circuit for receiving the signal supplied from the switching unit 76 (the signal arriving at the electrode 21) and decoding the value of the symbol included in the received signal. 71b. The receiving unit 71 is configured to be able to detect each of the detection pattern c1, the delimiter pattern STP, and the control information c2 described above by this decoding. In order to reduce the power consumption of the stylus 2, the receiving section 71 performs the receiving operation only intermittently until the detection pattern c1 is detected.

The waveform reproduction unit 71a binarizes the level of the charge (voltage) induced in the electrode 21 with a clock several times (for example, four times) the chip rate of the spreading code PN described above, and converts it into a binary string of positive and negative polarity values ( chip row) and output. The correlation calculator 71b stores the chip string output from the waveform reproducing unit 71a in a register, and converts the spread code PN (or at least one of inversion and cyclic shift to the spread code PN) while sequentially shifting with the clock. The symbol value included in the received signal is decoded by performing a correlation calculation with the code obtained by applying .

The receiving unit 71 successively determines whether or not the value of the symbol decoded by the correlation calculator 71b indicates the detection pattern c1 described above. As a result, when the detection pattern c1 is detected, the presence of the sensor controller 31 is detected, and an activation signal EN is sent to the control unit 90 to enable execution of processing according to the command indicated by the command signal. issue.

Further, when the detection pattern c1 is detected, the receiving section 71 switches the receiving operation from intermittent to continuous, and sequentially determines whether or not the value of the decoded symbol indicates the delimiting pattern STP described above. When the delimiting pattern STP is detected as a result, the receiving section 71 outputs the detection time t2 to the control section 90 .

After detecting the delimiter pattern STP, the receiving unit 71 receives command signals transmitted by the sensor controller 31 according to scheduling (described later) by the control unit 90 . Specifically, the values of a series of symbols decoded by the correlation calculator 71b during the reception operation are acquired as the control information c2 and output to the control section 90 .

The control unit 90 is configured by a microprocessor (MCU), and is activated when an activation signal EN is supplied from the receiving unit 71. Subsequently, based on the detection time t2 supplied from the receiving unit 71, various signals are generated. Generate a transmission/reception schedule such as Then, a process of generating a control signal SWC based on the generated transmission/reception schedule and supplying it to the switching unit 76, a process of controlling the receiving unit 71 so as to receive the command signal, and control information c2 supplied from the receiving unit 71 and a process of controlling the transmission unit 75 based on the above. The control of the transmission unit 75 includes determining whether to transmit a long burst signal or a burst signal and a data signal based on the received command signal, and determining whether to transmit a long burst signal or a burst signal. includes instructing the transmission unit 75 to that effect, and acquiring the data instructed to be transmitted by the control information c2 and supplying it to the transmission unit 75 when transmitting a data signal. The data supplied to the transmission unit 75 includes data indicating the writing pressure detected by the writing pressure detection sensor 23 .

The transmission section 75 is a circuit that generates a signal to be transmitted to the sensor controller 31 and supplies it to the electrode 21 , and is composed of the modulation section 73 and the booster circuit 74 .

The modulation section 73 is a circuit that generates a carrier signal (rectangular wave signal) having a predetermined frequency or a frequency controlled by the control section 90 and outputs the carrier signal as it is or after modulating it based on the control of the control section 90 . When transmitting the long burst signal and the burst signal, the modulating section 73 outputs the carrier signal as it is without modulating it, or after modulating it with a known value pattern shared with the sensor controller 31 . As a result, the long burst signal before boosting and the burst signal before boosting are output from the modulator 73 . On the other hand, when transmitting a data signal, the carrier signal is modulated (OOK, PSK, etc.) with the data supplied from the control section 90, and the resulting modulated signal is output. As a result, the data signal before boosting is output from the modulation section 73 .

The booster circuit 74 is a circuit that boosts the output signal of the modulation section 73 to a certain amplitude to generate a long burst signal, a burst signal, and a data signal. The long burst signal, burst signal, and data signal generated by the booster circuit 74 are sent out from the electrodes 21 to the space via the switching section 76 .

The configurations and operations of the sensor controller 31 and the stylus 2 according to the present embodiment have been described above. Next, the operations of the sensor controller 31 and the stylus 2 will be described in more detail with reference to the processing flow diagrams.

First, FIG. 9 is a processing flow diagram showing the overall operation of the sensor controller 31. As shown in FIG. As shown in the figure, the sensor controller 31 performs finger touch detection processing four times every time Tr defined by the reciprocal of the display refresh rate of the liquid crystal display (eg, 16.67 ms, which is the reciprocal of 60 Hz). (Steps S1 and S2) and four stylus detection processes (Step S3) are configured to repeat the same operation. Finger touch detection processing and stylus detection processing are alternately executed, and each finger touch detection processing is continuously executed for time Tf (eg, 1500 μs), and each stylus detection processing is continuously executed for time Ts (eg, 2500 μs). be. Note that the detection of the finger F is performed using two finger touch detection processes (steps S1 and S2) that are discontinuously performed with the stylus detection process interposed therebetween as a position detection unit of one finger touch.

FIG. 10 is a processing flow diagram showing stylus detection processing performed by the sensor controller 31. As shown in FIG. Although not shown, the sensor controller 31 stores a state flag indicating its own state. The states indicated by the state flags include a state in which the stylus is not detected and waiting for transmission of the pen activation signal (=0), a state in which the stylus is not detected and is waiting for a response to the pen activation signal (=1), and a state in which the stylus has been detected and the position has not been derived. State (=2) and stylus position derived state (=3) are included. The sensor controller 31 first refers to this state flag (step S10).

If the state flag referred to in step S10 is "0", the sensor controller 31 transmits a pen activation signal over a predetermined time T (for example, 2500 μs, which is the same as the time Ts shown in FIG. 9) (step S11). . Specifically, the repetition of the detection pattern c1 and the delimiter pattern STP are transmitted. After completing the continuous transmission of the pen activation signal, the sensor controller 31 sets the status flag to "1" (step S12), and returns the process to step S10.

When the state flag referred to in step S10 is "1", the sensor controller 31 first transmits a command signal (first uplink signal) indicating a transmission instruction of a long burst signal (step S13). Transmission of various command signals including this command signal requires a maximum time T0 (for example, 200 μs) as shown in FIG. Thereafter, the sensor controller 31 performs a long burst signal detection operation over time T1 (step S14). This detection operation is performed by the first half of the full range scan (first scan) described with reference to FIG. 7(a).

After the time T1 has elapsed and the operation of detecting the long burst signal is completed, the sensor controller 31 determines whether or not the long burst signal has been received (step S15). As a result, if it is determined that the data has not been received, the status flag is set to "0" (step S16), and the process returns to step S10. This step S16 is performed when the sensor controller 31 cannot receive the downlink signal because the stylus 2 is out of the sensing range SR shown in FIG. 1, for example. On the other hand, if it is determined that the command has been received in step S15, the sensor controller 31 sets the state flag to "2" (step S17), determines the command to be transmitted to the stylus 2 (step S18), and then The process is returned to step S10. The command determined here is an instruction to transmit a long burst signal.

If the state flag referred to in step S10 is "2", the sensor controller 31 first retransmits the command signal (first uplink signal) indicating the transmission instruction of the long burst signal (step S19). After that, the sensor controller 31 again executes the long burst signal detection operation over time T1 (step S20). This detection operation is performed by the second half of the full range scan (first scan) described with reference to FIG. 7(b). Note that if the first half of the operation (step S14) and the second half of the full range scan (step S20) can be executed within one time T1, these two steps S14 and S20 are executed in one process. You may

After the time T1 has passed and the operation of detecting the long burst signal is completed, the sensor controller 31 determines whether or not the long burst signal has been received (step S21). As a result, when it is determined that it has not been received, the state flag is set to "0" (step S22), and the process returns to step S10. This step S22 is performed when the sensor controller 31 cannot receive the downlink signal because the stylus 2 has left the sensing range SR shown in FIG. 1, for example. On the other hand, if it is determined that the signal has been received in step S21, the sensor controller 31 sets the state flag to "3" (step S23), and the detection result of the long burst signal in step S14 and the long burst signal in step S20 Based on the signal detection result, the position of the stylus 2 is derived (step S24). After determining the command to be transmitted to the stylus 2 (step S25), the process returns to step S10. The command determined here is an instruction to transmit various data (stylus ID, data indicating writing pressure, etc.) and also plays a role of an instruction to transmit a burst signal over time T2.

If the state flag referred to in step S10 is "3", the sensor controller 31 transmits a command signal (second uplink signal) indicating the command determined in step S25 or step S32 described later (step S26). ). After that, the sensor controller 31 performs the burst signal detection operation for a time T2 shorter than the time T1 (step S27), and when the burst signal is detected, the stylus is detected based on the detection intensity of each of the linear electrodes 30X and 30Y. 2 is derived (step S28). The burst signal detection operation in step S27 is performed by the sector scan (second scan) described with reference to FIG. 7(c).

After the time T2 has passed and the burst signal detection operation is finished, the sensor controller 31 next performs the data signal detection operation (step S29). This detection operation includes decoding of the data signal. The data signal detection operation is performed using one linear electrode 30X or linear electrode 30Y selected based on the position coordinates derived in the previous step S28. This makes it possible to make full use of the data signal detection period, so that more data can be received from the stylus 2 .

After completing the data signal detection operation, the sensor controller 31 determines whether or not a burst signal or a data signal has been received (step S30). As a result, if it is determined that neither has been received, the status flag is set to "0" (step S31), and the process returns to step S10. This step S31 is performed when the sensor controller 31 cannot receive the downlink signal because the stylus 2 has left the sensing range SR shown in FIG. 1, for example. On the other hand, if it is determined in step S30 that at least one of them has been received, the next command to be transmitted to the stylus 2 is determined (step S32), and the process returns to step S10. The command determined here is also an instruction to transmit various data (stylus ID, data indicating writing pressure, etc.) and also plays a role of an instruction to transmit a burst signal over time T2.

Next, FIG. 11 is a processing flow diagram showing the operation of the stylus 2 corresponding to FIG. Although not shown, the stylus 2 also stores a status flag indicating its own status. The states indicated by the state flags include a sensor controller undetected state (=0) and a sensor controller detected state (=1). The stylus 2 first refers to this status flag (step S40).

If the state flag referred to in step S40 is "0", the stylus 2 first enters the receiving operation pause state (step S41). Then, after a predetermined time has passed, detection of the detection pattern c1 described above is attempted (step S42). The pause period in step S41 is provided in order to reduce the power consumption of the stylus 2 by intermittently performing the detection operation of the detection pattern c1.

The stylus 2 then determines whether or not the detection pattern c1 is detected by the trial of step S42 (step S43). As a result, when it determines with it not being detected, a process is returned to step S40. On the other hand, if it is determined that the delimiter pattern STP is detected, the stylus 2 continues detecting the detected pattern c1 and symbols forming the delimiter pattern STP (step S44). Then, when the delimiting pattern STP is detected, a process of synchronizing with the sensor controller 31 is performed based on the detection time (step S45), the state flag is set to "1" (step S46), and the process proceeds to step S40. Return processing. Specifically, the synchronization processing in step S45 is processing for generating a transmission/reception schedule by the control unit 90 shown in FIG.

If the state flag referred to in step S40 is "1", the stylus 2 first detects a command signal (step S47). This detection operation is performed over time T0. Next, the stylus 2 determines whether or not the command signal has been detected by the detection operation of step S47, and if so, what is the content indicated by the command signal (step S48). If it is determined that the command signal has not been detected, the status flag is set to "0" (step S49), and the process returns to step S40. This step S49 is performed when the stylus 2 cannot detect the uplink signal because the stylus 2 has left the sensing range SR shown in FIG. 1, for example.

On the other hand, if it is determined in step S48 that the command signal indicating the transmission instruction of the long burst signal has been detected, the stylus 2 decides to transmit the long burst signal, and performs processing for transmitting the long burst signal over time T1 (step S50). Specifically, the signal having the predetermined waveform constituting the long burst signal is continuously transmitted over time T1. After that, the process returns to step S40.

If it is determined in step S48 that a command signal indicating a data transmission instruction has been detected, the stylus 2 decides to transmit a burst signal and performs processing for transmitting the burst signal over time T2 (step S51). Specifically, the signal having the predetermined waveform constituting the burst signal is continuously transmitted over time T2. The stylus 2 then performs a process of transmitting a data signal containing the indicated data (step S52). After that, the process returns to step S40.

As described above, according to the present embodiment, the sensor controller 31 detects the stylus 2 in a stylus undetected state in which there is a high possibility that the stylus 2 is hovering. You can expect to send burst signals. Therefore, while making the detection operation time per linear electrode longer than when receiving a normal burst signal, more linear electrodes (in this embodiment, all linear electrodes 30Y or linear electrode 30X) to detect the burst signal. It becomes possible to reduce the possibility of

Further, according to the present embodiment, since the full-range scan is used when receiving the long burst signal, the detection operation time per linear electrode can be reduced while ensuring the state in which the burst signal can be detected over the entire touch surface. can be made even longer.

Further, according to the present embodiment, since the sensor controller 31 instructs the stylus 2 to transmit the long burst signal by the command signal indicating the transmission instruction of the long burst signal, the stylus 2 receives the long burst signal can clearly know when to send the

Although preferred embodiments of the present invention have been described above, the present invention is by no means limited to such embodiments, and the present invention can be implemented in various forms without departing from the gist thereof. is of course.

First to sixth modifications of the above embodiment will be described below.

FIG. 12 is a diagram showing the configuration of a stylus 2 according to a first modification of the above embodiment. The sensor controller 31 and the stylus 2 according to this modified example are different from the above-described embodiment in that wireless communication that does not use the capacitive coupling method is used to transmit uplink signals. Another difference from the above embodiment is that the stylus 2 supports transmission of two types of downlink signals DS1 and DS2 having different carrier signal formats. Both of the downlink signals DS1 and DS2 are configured to be able to transmit the above-described long burst signal, burst signal, and data signal, and the stylus 2 selectively uses these depending on the type of sensor controller 31 that is approaching. Hereinafter, the configuration of the stylus 2 according to this modified example will be described in detail with reference to FIG. 12 .

The stylus 2 according to this modified example includes an electrode 21, a signal processing section 24, a power supply 25, an amplifier section 26, and a receiving section 27, as shown in FIG.

The receiving unit 27 is a functional unit that is configured to be able to perform communication by, for example, Bluetooth (registered trademark) as wireless communication. do.

The signal processing unit 24 is a functional unit having a function of selectively transmitting two types of downlink signals DS1 and DS2 and a function of receiving the uplink signal US via the receiving unit 27. Specifically, , a control unit 91, a booster unit 92, an oscillation unit 93, and a switch unit 94. FIG.

The booster 92 has a function of boosting the DC voltage supplied from the power supply 25 to generate the DC voltage V1. In a specific example, the boosting section 92 is composed of a DC-DC converter or a charge pump circuit.

The oscillator 93 has a function of generating an unmodulated sine wave signal (carrier wave signal) that oscillates at a predetermined frequency by performing an oscillating operation based on the DC voltage supplied from the power supply 25 . The amplifier 26 has a function of generating an unmodulated sine wave signal v2 by amplifying the sine wave signal generated by the oscillator 93 with a predetermined amplification factor. As shown in FIG. 12, the amplifier section 26 is preferably configured by an amplifier circuit configured by a transformer and a capacitor.

The switch unit 94 is a switch element with three contacts in one circuit, and has a terminal a connected to the output end of the booster unit 92, a terminal b connected to the output end of the amplifier unit 26, and a power supply wiring to which a ground potential is supplied. and a common terminal c connected to the electrode 21 .

The control unit 91 is an IC that supplies a control signal Ctrl for controlling the switch unit 94 and controls the reception unit 27 to receive an uplink signal transmitted by the sensor controller 31 . configured to operate from electric power; In a specific example, the controller 91 may be an ASIC or MCU. The control unit 91 controls the content of the uplink signal received via the receiving unit 27 or the fact that no uplink signal is received (the sensor controller 31 supports only one-way communication from the stylus 2 to the sensor controller 31). case), it is determined which of the downlink signals DS1 and DS2 is used to transmit the long burst signal, the burst signal, and the data signal. Further, it determines transmission/reception schedules for various signals and the like in the same manner as the control unit 90 shown in FIG. 8, and controls the switch unit 94 based on the determined transmission/reception schedules.

The control section 91 when transmitting the downlink signal DS1 controls the switch section 94 so as to function as a first switch section provided between the output terminal of the booster section 92 and the electrode 21 . That is, the switching unit 94 is switched between a state in which the terminal a is connected to the common terminal c and a state in which the terminal g is connected to the common terminal c. The state in which the terminal a is connected to the common terminal c corresponds to the state in which the first switch section is turned on, and the state in which the terminal g is connected to the common terminal c corresponds to the state in which the first switch section is turned off. corresponds to the state of

When transmitting a burst signal or a long burst signal using the downlink signal DS1, the control unit 91 performs switching control of the switch unit 94 periodically at a predetermined cycle. When the terminal a is connected to the common terminal c, the DC voltage V1 becomes the output voltage of the switch section 94 . On the other hand, when the terminal g is connected to the common terminal c, the ground potential becomes the output voltage of the switch section 94 . Therefore, the switch section 94 outputs an unmodulated pulse train signal, which becomes a long burst signal or burst signal.

On the other hand, when a data signal is transmitted using the downlink signal DS1, the control unit 91 converts data such as writing pressure level P and switch information SW indicating ON/OFF of a side switch (not shown) provided in the stylus 2. Accordingly, switching control of the switch unit 94 is performed. Note that this data may include other information such as a stylus ID (identification information of the stylus 2). Through this switching control, the control unit 91 generates a data signal, which is a pulse train signal modulated based on data. On/off modulation, frequency modulation, and the like are conceivable as specific methods for modulating the pulse train signal by the control unit 91 .

The control section 91 when transmitting the downlink signal DS2 controls the switch section 94 so as to function as a second switch section provided between the output terminal of the amplification section 26 and the electrode 21 . That is, the switching unit 94 is switched between a state in which the terminal b is connected to the common terminal c and a state in which the terminal g is connected to the common terminal c. A state in which the terminal b is connected to the common terminal c corresponds to a state in which the second switch section is turned on, and a state in which the terminal g is connected to the common terminal c corresponds to a state in which the second switch section is turned off. corresponds to the state of

When transmitting a burst signal or a long burst signal using the downlink signal DS2, the control section 91 fixes the switch section 94 to the terminal b side. Therefore, the switch section 94 outputs an unmodulated sine wave signal v2, which becomes a long burst signal or burst signal.

On the other hand, when a data signal is transmitted using the downlink signal DS2, the control section 91 performs switching control of the switch section 94 based on data such as the writing pressure level P and the switch information SW. Also in this case, the data may include other information such as the stylus ID. Through this switching control, the control section 91 generates a data signal, which is a sinusoidal signal modulated based on the data. On/off modulation is adopted as a specific method for modulating the sine wave signal by the control unit 91 .

As described above, according to this modified example, Bluetooth (registered trademark) can be used for transmission and reception of uplink signals. Although an example using Bluetooth (registered trademark) has been described here, it is of course possible to use proximity wireless communication other than Bluetooth (registered trademark) for transmission and reception of uplink signals.

Further, according to this modification, the stylus 2 can perform bi-directional or uni-directional communication with a plurality of sensor controllers 31 of different types by selectively using the downlink signals DS1 and DS2. .

FIG. 13 is a processing flow diagram showing the operation of the stylus 2 according to the second modification of the above embodiment. The stylus 2 according to this modification transmits a long burst signal immediately upon receiving any uplink signal at the stage of not detecting the sensor controller 31, and determines whether or not to transmit a burst signal immediately before a data signal. It is different from the above-described embodiment in that Hereinafter, the operation of the stylus 2 according to this modified example will be described in detail with reference to FIG. 13 .

As shown in FIG. 13, the stylus 2 according to this modification first performs an uplink signal detection operation (step S60). Then, it is determined whether or not an uplink signal has been detected by this detection operation (step S61), and if it is determined that no uplink signal has been detected, the process returns to step S60 and the detection operation is repeated. On the other hand, when it is determined that it has been detected, the long burst signal is transmitted without waiting for the command signal (step S62). Specifically, the signal having the predetermined waveform described above is transmitted over time T1.

After transmitting the long burst signal, the stylus 2 performs a command signal detection operation (step S63). Then, it is determined whether or not a command signal indicating a data transmission instruction has been detected (step S64), and if it is determined that it has not been detected, the process returns to step S62 to repeat transmission of the long burst signal. On the other hand, if it is determined that the burst signal has been detected, then it is determined whether or not to transmit the burst signal (step S65). This determination is preferably made based on the content of the detected command signal. By doing so, it becomes possible for the sensor controller 31 to control whether or not the stylus 2 transmits a burst signal.

Processing when it is determined to transmit a burst signal in step S65 is the same as steps S51 and S52 shown in FIG. Specifically, the stylus 2 transmits a burst signal by transmitting a signal having a predetermined waveform over a period of time T2 (step S66). A data signal including data based on is transmitted (step S67). On the other hand, if the stylus 2 determines not to transmit the burst signal in step S65, the stylus 2 transmits a data signal containing data based on the instruction of the command signal detected in step S63 over time T1 (step S68).

After transmitting the data signal in step S67 or step S68, the stylus 2 returns the process to step S63. As a result, it becomes possible to continuously transmit data according to instructions from the sensor controller 31 .

As described above, according to this modified example, the stylus 2 can transmit a long burst signal without waiting for a command signal including an instruction to transmit a long burst signal. Therefore, it is possible to transmit a long burst signal even to the sensor controller 31 that does not particularly support long burst signals.

Further, since the stylus 2 determines whether or not to transmit a burst signal immediately before the data signal, when the sensor controller 31 does not require the transmission of the burst signal from the stylus 2, the stylus 2 Data signals can be transmitted over a longer period of time (that is, more data can be transmitted), and sensor controller 31 can acquire more data.

FIG. 14 is a processing flow diagram showing the operation of the sensor controller 31 according to the third modification of the above embodiment. In one stylus detection process (step S3 in FIG. 9), the sensor controller 31 according to this modification sends a command indicating an instruction to send a long burst signal following transmission of a pen activation signal or execution of the first half of a full range scan. This embodiment differs from the above embodiment in that signals are transmitted. Hereinafter, the operation of the sensor controller 31 according to this modified example will be described in detail with reference to FIG.

As shown in FIG. 14, when the state flag referred to in step S10 is "0", the sensor controller 31 according to this modified example has the pen activated for a shorter time (specifically, time T1) than in the example of FIG. A signal is transmitted (step S71). Next, the sensor controller 31 transmits a command signal (first uplink signal) indicating an instruction to transmit a long burst signal (step S72), then sets the state flag to "1" (step S12), and then step S10. Return processing to .

Further, when the state flag referred to in step S10 is "1", the sensor controller 31 according to the present modification performs a long burst signal detection operation over time T1 (step S73), and then transmits the long burst signal. A command signal (first uplink signal) indicating an instruction is transmitted again (step S74). It is the same as step S14 shown in FIG. 10 in that the detection operation in step S73 is performed in the first half of the full range scan, but compared to the example in FIG. is reversed.

Further, when the state flag referred to in step S10 is "2", the sensor controller 31 according to the present modification performs a long burst signal detection operation over time T (step S63). This detection operation is performed by the second half of the full range scan, which is the same as step S14 shown in FIG. can be used for detection operations. Since subsequent processing is the same as the example of FIG. 10, detailed description is omitted.

Here, in this modification, it is preferable that the long burst signal transmission instruction transmitted in steps S72 and S74 also include information indicating the transmission duration of the long burst signal. The stylus 2 preferably controls the transmission duration of the long burst signal according to the transmission duration indicated by this information. This makes it possible to match the period during which the sensor controller 31 detects the long burst signal with the period during which the stylus 2 transmits the long burst signal.

As described above, according to this modified example, the second half of the full-range scan can be performed over a longer period of time than in the above-described embodiment. Therefore, the reception time per linear electrode 30X can be further lengthened, so that the burst signal can be received by the sensor controller 31 more reliably than in the above embodiment.

FIG. 15 is a diagram showing a long burst signal transmitted by the stylus 2 according to the fourth modification of the above embodiment. The sensor controller 31 and the stylus 2 according to this modified example differ from those of the above embodiment in the format of the long burst signal. Hereinafter, the format of the long burst signal according to this modification will be described in detail with reference to FIG.

As shown in FIG. 15, the long burst signal according to this modification is composed of a pattern in which a signal of frequency f1 (first frequency) and a signal of frequency f2 (second frequency) different from frequency f1 are continuous. be done. Specifically, the frequency of the first half is f1, and the frequency of the second half is f2.

If the long burst signal has a single frequency over the entire interval, the sensor controller 31 cannot obtain any information from the received long burst signal. Therefore, there is a possibility that the sensor controller 31 may receive, for example, simple white noise or frequency selective noise having a strong component near frequency f1, erroneously recognizing it as a long burst signal. On the other hand, according to the long burst signal according to this modification, the sensor controller 31 determines that the received signal is the long burst signal based on the fact that the two frequencies are detected in a known order. be able to. Therefore, according to this modification, it is possible to reduce the possibility that the sensor controller 31 will misidentify a signal that is not a long burst signal as a long burst signal and operate.

In this modification, a full-range scan for long burst signal detection is performed, for example, by first scanning the odd-numbered linear electrodes 30Y and then scanning the even-numbered linear electrodes 30Y. This is so that the sensor controller 31 can receive both the first half and the second half of the long burst signal. Note that when the time T1 of the long burst signal can be sufficiently long, all the linear conductors 30Y can be sequentially scanned at the frequency f1, and then all the linear conductors 30Y can be sequentially scanned again at the frequency f2. good.

As described above, according to this modified example, it is possible to reduce the possibility that the sensor controller 31 will misidentify a signal that is not a long burst signal as a long burst signal and operate.

In this modified example, an example in which the long burst signal has different frequencies in the first half and the second half has been described. Any feature, if any, may be provided in the long burst signal. For example, the long burst signal may be a signal in which L frequencies are changed in a predetermined sequence predetermined with the sensor controller 31 . In this case, the sensor controller 31 may use the N linear electrodes 30Y (or the M linear conductors 30X) and perform the scanning operation repeatedly L times while changing the frequency.

FIG. 16 is a processing flow diagram showing the operation of the stylus 2 according to the fifth modification of the above embodiment. The sensor controller 31 and stylus 2 according to this modified example differ from the above embodiment in that the stylus 2 determines based on the uplink signal that the sensor controller 31 has not yet detected the stylus 2 . Hereinafter, the operation of the stylus 2 according to this modified example will be described in detail with reference to FIG.

As shown in FIG. 16, the stylus 2 according to this modification first enters a sleep state (step S80). This sleep state is the same as the receiving operation pause state (step S31) shown in FIG.

After a predetermined period of time has elapsed since entering the sleep state, the stylus 2 performs an uplink signal detection operation (step S81). Then, it is determined whether or not an uplink signal has been detected by this detection operation (step S82), and if it is determined that no uplink signal has been detected, the process returns to step S80 and enters the sleep state again. On the other hand, if it is determined that the stylus 2 has been detected, it is determined whether or not the uplink signal indicates that the sensor controller 31 has not yet detected the stylus 2 (undetected state) (step S83). ). This determination process is executed by the control unit 90 in the example of the stylus 2 shown in FIG. 8, and by the control unit 91 in the example of the stylus 2 shown in FIG.

As a specific method of determination in step S83, for example, the following can be considered. The first is a case where the sensor controller 31 explicitly transmits an uplink signal indicating that the stylus 2 is not detected. In this case, the stylus 2 may perform the determination of step S83 based on whether or not the uplink signal has been received. The second is a case where the sensor controller 31 transmits a command signal indicating an instruction to transmit a long burst signal, as described in the above embodiment. The sensor controller 31 transmits a command signal indicating an instruction to transmit a long burst signal when the sensor controller 31 has not yet detected the stylus 2 as described with reference to FIG. Therefore, the stylus 2 in this case can make the determination in step S83 based on whether or not it has received the command signal indicating the transmission instruction of the long burst signal.

If a positive determination result is obtained in step S83, the stylus 2 transmits a long burst signal (step S84). Specifically, the signal having the predetermined waveform described above is transmitted over time T1. It goes without saying that the long burst signal transmitted in this case may be the long burst signal shown in FIG. 15 (a signal having characteristics that allow distinguishing between white noise and long burst signals).

On the other hand, if a negative determination result is obtained in step S83, the stylus 2 next determines whether or not to transmit a burst signal (step S85). The subsequent processing (steps S85 to S88) is the same as the processing of steps S65 to S68 described with reference to FIG. 13, so detailed description is omitted.

As described above, according to this modification, the stylus 2 determines whether or not the sensor controller 31 has detected the stylus 2, and based on the result, transmits a long burst signal, or transmits a burst signal and a burst signal. It becomes possible to decide whether to transmit data signals (or to transmit only data signals).

FIG. 17 is a diagram for explaining specific position exclusion processing according to the sixth modification of the above embodiment. FIG. 18 is a processing flow diagram showing the operation of the sensor controller 31 according to this modification. In this modification, the finger detected in the finger touch detection process (steps S1 and S2 in FIG. 9) is selected from one or more positions of the stylus 2 derived as a result of the stylus detection process (step S3 in FIG. 9). This is to remove the object positioned within the touch area (information indicating the area touched by the finger F shown in FIG. 1). A detailed description will be given below.

FIG. 17(a) shows the finger touch areas A1 and A2 detected by the finger touch detection process, and FIG. 17(b) shows the finger touch areas A1 and A2 detected by the stylus detection process executed immediately after the finger touch detection process of FIG. 17(a). The derived positions B1 to B3 of the stylus 2 are shown.

In the finger touch areas A1 and A2 in FIG. 17(a), as described above, part of the current flowing on the linear electrodes of the sensor 30 is caused by capacitive coupling between the finger F and the linear electrodes 30X and 30Y. It is detected by flowing out in the direction of the human body. In FIG. 17(a), the area of the finger touch area A2 is much larger than the area of the finger touch area A1. It is formed when the palm, fist, or the like comes into contact with the touch surface. Therefore, it is usually invalidated by separate processing (palm rejection processing) based on the size of the area. FIG. 17(a) shows the state before invalidation.

Positions B1 to B3 of the stylus 2 shown in FIG. 17B are derived based on the detected intensity of the burst signal at each of the linear electrodes 30X and 30Y in step S20 of FIG. 10, for example. The burst signal arriving at the sensor 30 (see FIG. 2) includes, in addition to the components coming directly from the electrodes 21 (see FIGS. 8 and 12) of the stylus 2, the signal passing through the hand holding the stylus 2 and the opposite hand. components that arrive as Of the three positions B1 to B3 detected in FIG. 17(b), only the position B3 is derived by the component that directly reaches the sensor 30 from the electrode 21 of the stylus 2, and the other two are It is derived by the component that reaches the sensor 30 via the hand holding the stylus 2 and the other hand.

Here, referring to FIG. 17(a) again, it is understood that finger touch areas A1 and A2 are detected at the same positions as positions B1 and B2. This is because the detection of the positions B1 and B2 is due to the proximity of the hand to the touch surface, and such a hand can also be detected by finger touch detection processing. The sensor controller 31 according to this modification utilizes such a relationship between the finger touch area and the stylus position, and refers to the result of the finger touch detection process to determine the position of the stylus 2 derived by the stylus detection process. Positions B1 and B2 are selected from among B1 to B3 and removed (excluded). The operation of the sensor controller 31 for realizing this will be described in detail below with reference to FIG.

As shown in FIG. 18, the sensor controller 31 according to this modification first detects the finger touch area (step S90). This is a process performed in the finger touch detection process (steps S1 and S2) shown in FIG.

After that, when the stylus detection process (step S3) shown in FIG. 9 is performed, the sensor controller 31 first acquires one or more position candidates of the stylus 2 by the process shown in step S20 of FIG. S91). Further, the sensor controller 31 acquires one or more finger touch areas detected in step S90 (step S92). It should be noted that when the palm rejection process described above is performed, the finger touch area acquired here is the area before the palm rejection process.

Next, the sensor controller 31 repeats the processes from step S94 onward for each of the candidates for the position of the stylus 2 acquired in step S91. Specifically, first, it is determined whether or not the position indicated by the candidate is included in any of the one or more finger touch areas acquired in step S92 (step S94). If it is determined not to be included here, the position indicated by the candidate is recognized as the position of the stylus 2, and normal processing is performed (step S95). On the other hand, if it is determined that the candidate is included, the candidate is invalidated (step S96). An invalidated candidate will not be used at least as a stylus 2 position in subsequent processing. This invalidation processing may be realized by not outputting the position of the stylus 2 from the sensor controller 31 to the system controller of the electronic device 3, or outputting the position of the stylus 2 and then The position may be realized by indicating with a flag or the like that it is an invalid area.

As described above, according to the present modification, the sensor controller 31 selects the position of the stylus 2 derived by the stylus detection process, and selects the position of the stylus 2 via the hand holding the stylus 2 or the opposite hand. The position derived by the component of the burst signal arriving at sensor 30 can be removed.

Further, in the above embodiment, all of the N linear electrodes 30Y and the M linear electrodes 30X are used to execute the full-range scan. It is sufficient to perform many scans (that is, scans using a large number of linear electrodes), and it is not always necessary to use all of the N linear electrodes 30Y and the M linear electrodes 30X. That is, the full range scan may be performed using the detection area of the first range, which is the entire or a part of the touch surface, and the sector scan may be performed using the detection area selected from the first range. You can use it. In this case, the command signal (command signal indicating the transmission instruction of the long burst signal) to be performed before the full range scan should be transmitted from the first range, and the command signal (burst signal and A command signal indicating an instruction to transmit a data signal) may be transmitted from the selected range.

In the above-described embodiment, the operation of the full range scan is divided into a scan (first half) in which the N linear electrodes 30Y are sequentially used and a scan (second half) in which the M linear electrodes 30X are sequentially used. However, if the transmission duration T1 of the long burst signal can be sufficiently long, the position of the stylus 2 (two-dimensional coordinate position) can be determined using the linear conductor 30X after the operation of the linear electrode 30Y. It may be specified.

Further, in the above embodiment, an example in which the data signal is not transmitted after the long burst signal is transmitted has been described, but the data signal may be transmitted following the long burst signal. The data signal transmission duration in this case may be shorter than the data signal transmission duration of the burst signal shown in FIG. This data signal is suitable for transmitting data such as the ON/OFF state of a switch provided on the housing of the stylus 2, which can indicate the state with a smaller number of bits than writing pressure or the like.

2 Stylus 3 Electronic device 21 Electrode 23 Writing pressure detection sensor 24 Signal processing unit 25 Power supply 26 Amplifier unit 27 Receiving unit 30 Sensors 30X, 30Y Linear electrode 31 Sensor controller 40 Selecting unit 41x, 41y Conductor selecting circuit 44x, 44y Switch 50 Receiving Unit 51 Amplifier circuit 52 Detection circuit 53 Converter 60 Transmission unit 61 Pattern supply unit 62 Switch 63 Spreading unit 64 Code string holding unit 65 Transmission guard unit 70 Logic unit 71 Reception unit 71a Waveform reproduction unit 71b Correlation calculator 73 Modulation unit 74 Booster circuit 75 Transmitter 76 Switcher 90 Controller 91 Controller 92 Booster 93 Oscillator 94 Switcher A1, A2 Finger touch areas B1 to B3 Stylus positions DS1, DS2 Downlink signal EN Activation signal F Finger P Writing pressure level Res Data SR Sensing range SW Switch information US Uplink signal

Claims (7)

Connected to a matrix electrode comprising M first electrodes each extending in a first direction and N second electrodes each extending in a second direction different from the first direction a sensor controller comprising:
A predetermined signal is supplied to each of the M first electrodes, and the predetermined signal detected by each of the N second electrodes indicates an area touched by a finger, respectively. a finger touch detection step of detecting one or more finger touch areas;
a full range scanning step of detecting an undetected stylus and deriving position coordinates of the stylus using at least some of the M first electrodes and at least some of the N second electrodes; ,
The number of the first electrodes that is less than the number of the first electrodes used in the full range scanning step, and the number of the second electrodes that is less than the number of the second electrodes used in the full range scanning step a sector scanning step of deriving the position coordinates of the already detected stylus using
a determination step of determining whether each of the one or more position coordinates derived in the sector scanning step is included in any of the one or more finger touch areas detected in the finger touch detection step; ,
an invalidation step of invalidating the position coordinates determined to be included in the determination step;
A sensor controller configured to perform further comprising a palm rejection step of invalidating the one or more finger touch areas detected by the finger touch detection step by palm rejection processing based on the size of each area;
In the determination step, before executing the palm rejection step, for each of the one or more position coordinates derived in the sector scan step, the one or more finger touch areas detected in the finger touch detection step. Perform processing to determine whether it is included in any
A sensor controller according to claim 1 . The invalidation by the invalidation step is a process of not outputting the position coordinates determined to be included in the determination step to the system controller.
3. The sensor controller according to claim 1 or 2. The invalidation by the invalidation step is a process of outputting the position coordinates determined to be included in the determination step to the system controller together with information indicating that it is an invalid area.
3. The sensor controller according to claim 1 or 2. In the sector scanning step, the number of the first electrodes of the burst signal transmitted by the already detected stylus is smaller than the number of the first electrodes used in the full range scanning step, and the full range scanning step. Deriving the position coordinates of the already detected stylus based on the detected intensity of each of the second electrodes, which is smaller in number than the number of the second electrodes used in
5. The sensor controller according to any one of claims 1-4. A matrix electrode comprising M first electrodes each extending in a first direction and N second electrodes each extending in a second direction different from the first direction A computer-implemented method comprising:
The computer supplies a predetermined signal to each of the M first electrodes, and by the predetermined signal detected by each of the N second electrodes, each touched by a finger. a finger touch detection step of detecting one or more finger touch areas indicating the area where the finger touches;
The computer uses at least some of the M first electrodes and at least some of the N second electrodes to detect an undetected stylus and derive position coordinates of the stylus. a range scanning step;
The computer selects a number of the first electrodes that is less than the number of the first electrodes used in the full-range scanning step and a number of the second electrodes that is less than the number of the second electrodes used in the full-range scanning step. a sector scanning step of deriving the already detected position coordinates of the stylus using the second electrode;
The computer determines whether each of the one or more position coordinates derived in the sector scanning step is included in any of the one or more finger touch areas detected in the finger touch detection step. a determination step to
an invalidation step in which the computer invalidates the position coordinates determined to be included in the determination step;
method including. a matrix electrode comprising M first electrodes each extending in a first direction and N second electrodes each extending in a second direction different from the first direction; and a control unit connected to the matrix electrodes,
The control unit
A predetermined signal is supplied to each of the M first electrodes, and the predetermined signal detected by each of the N second electrodes indicates an area touched by a finger, respectively. Detecting one or more finger touch areas,
Performing a full range scan using at least some of the M first electrodes and at least some of the N second electrodes to detect an undetected stylus and derive position coordinates of the stylus death,
The number of the first electrodes that is less than the number of the first electrodes used in the full range scan, and the number of the second electrodes that is less than the number of the second electrodes used in the full range scan. to perform a sector scan to derive the position coordinates of the already detected stylus,
determining whether each of the one or more position coordinates derived in the sector scan is included in any of the one or more finger touch areas;
invalidating the position coordinates determined to be included in the determination ;
Electronics.

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