JP7209064B2 - Pointer position detection method - Google Patents

Description

The present invention relates to a pointer position detection method, and more particularly to a pointer position detection method for simultaneously detecting an active electrostatic electronic pen and detecting a passive pointer such as a finger.

Conventionally, as an electronic pen, an electromagnetic resonance type pen (hereinafter referred to as "EMR pen") is known. An EMR pen is an electronic pen configured to transmit an alternating magnetic field from the pen tip. The tip of the EMR pen is made of a non-conductor such as resin so as not to disturb the alternating magnetic field.

In recent years, development of active electrostatic pens (hereinafter referred to as "active pens") has progressed. An active pen is an electronic pen that is configured to transmit signals through an electric field from the pen tip. The tip of an active pen consists of a conductor (pen electrode), such as metal, which acts as an antenna to generate an electric field.

Further, in recent years, there has been an increasing number of cases where a finger or an auxiliary device that does not transmit a signal like a finger (hereinafter collectively referred to as a "passive pointer") is used in combination with an electronic pen. For example, while drawing a picture with the electronic pen in the right hand, an auxiliary operation such as zooming in, zooming out, or rotating is performed with the fingers of the left hand or an auxiliary device. In such a case, the position detector that detects the pointer needs to detect the electronic pen and the passive pointer in parallel.

Patent Literature 1 discloses an example of a position detector that performs EMR pen detection and passive pointer detection in parallel. As shown in FIG. 4 of the same document, in a position detector that performs EMR pen detection and passive pointer detection in parallel, it is necessary to prepare separate sensors for each detection. The detection sensor of the EMR pen is provided with the function of generating an alternating magnetic field and the function of receiving the signal transmitted by the EMR pen. On the other hand, the passive pointer detection sensor is provided with a function of detecting capacitive coupling that occurs between the tip (for example, fingertip) of the passive pointer and an electrode arranged in the sensor. Since the passive pointer does not transmit a signal in response to the alternating magnetic field, and the EMR pen does not capacitively couple with the electrodes in the sensor, the EMR pen detection and the passive pointer detection are performed at exactly the same timing (by time division). ) can be executed.

Further, Patent Literature 2 discloses an example of a position detector that performs detection of an active pen and detection of a passive pointer in parallel. As also shown in FIG. 6 of the same document, active pen detection and passive pointer detection are performed using the same sensor. As for the passive pointer, this sensor detects the capacitive coupling between the tip of the passive pointer and the electrodes arranged in the sensor, similar to the sensor for detecting the passive pointer described above with respect to Patent Document 1. Run discovery. For active pens, on the other hand, detection is performed by sending a signal to the active pen and, in response, receiving the signal sent by the active pen. At this time, the conductor (pen electrode) arranged at the tip of the active pen and the electrode arranged in the sensor each function as an antenna for transmitting and receiving signals. Since passive pointer detection and active pen detection are performed by the same sensor, active pen detection and passive pointer detection cannot be performed at exactly the same timing, and both are performed in a time-sharing manner. .

Japanese Patent No. 4787087 Japanese Patent No. 6082172

By the way, the conventional position detector that detects the active pen and the passive pointer in parallel has the problem of erroneously recognizing the contact position of the active pen and the contact position of the passive pointer. , was in need of improvement. A detailed description will be given below.

First, the reason why the position detector erroneously recognizes the contact position of the active pen as the contact position of the passive pointer is that the pen electrode of the active pen causes capacitive coupling with the electrode in the sensor. Since the position detector cannot distinguish this capacitive coupling from the capacitive coupling caused by the contact of the passive pointer, it erroneously recognizes that the passive pointer has come into contact. In recent years, there are many position detectors that are configured to recognize multiple passive pointers. It will be erroneously recognized as contact.

Next, the position detector mistakenly recognizes the contact position of the passive pointer as the contact position of the active pen. This is because Since the position detector cannot distinguish the signal thus received from the signal directly transmitted from the pen electrode of the active pen, the contact position of the palm is erroneously recognized as the contact position of the active pen.

SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a pointer position detecting method capable of correctly identifying the contact position of an active pen and the contact position of a passive pointer.

Also, as described above, the detection of the active pen and the detection of the passive pointer are executed in a time division manner. Assuming that the time required for active pen detection is 3 milliseconds per detection and the time required for passive pointer detection is 2 milliseconds per detection, active pen detection and passive pointer detection are performed alternately. The detection rate of the pen and the detection rate of the passive pointer are equal (both about 200 (1/5×1000) times/second).

In such a case, in order to further improve the active pen detection rate, for example, it is conceivable to perform active pen detection twice in succession and then perform passive pointer detection once.

However, if a control method is adopted in which the active pen detection and the passive pen detection are simply performed at an appropriate number of times as described above, the interval between active pen detections may not be constant. For example, as in the example above, after two consecutive active pen detections, the next active pen detection will be delayed until the passive pointer detection is complete. As a result, in a drawing application that expects that the coordinate data of the active pen sequentially output from the sensor controller is transmitted at equal time intervals, the drawing results become unnatural. Therefore, improvement was required.

Therefore, another object of the present invention is to provide a pointer position detection method that can detect the active pen at regular intervals while maintaining the detection rate of both the active pen and the passive pointer.

Further, when the position detector detects the active pen, it may erroneously recognize a position where neither the active pen nor the passive pointer is in contact as the contact position of the active pen. This forms a current path from the pen electrode of the active pen through the electrode in the sensor, into the arm opposite the hand holding the active pen, and back to the active pen via the human body, resulting in This is because the transmission signal of the active pen may be detected below the arm. Hereinafter, the contact position of the active pen that is erroneously recognized in this way will be referred to as a "ghost position".

For example, if the active pen suddenly moves from the bezel area of the tablet that constitutes the position detector into the touch surface, the position detector may detect a ghost position before detecting the actual pen position. be. In that case, an unnecessary line segment is drawn between the detected ghost position and the actual pen position detected immediately after that, so an improvement has been required.

Therefore, still another object of the present invention is to provide a pointer position detection method that can prevent unnecessary line segments from being drawn due to the presence of a ghost position.

A pointer position detection method according to the present invention is executed by a sensor controller connected to a sensor pattern. A pointer position detection method for detecting a position of a pen, and detecting a pen signal transmitted through the pen electrode, and determining the position of the active pen based on the level of the detected pen signal. Detecting one or more candidate touch positions, each of which is a candidate for the position of the passive pointer, by a pen detection step of detecting a pen position and detecting a change in capacitance in the sensor pattern; a touch detection step of outputting one or more candidate touch positions other than the pen position as a passive pointer position, which is the position of the passive pointer.

A pointer position detection method according to another aspect of the present invention is a pointer position detection method existing in a predetermined area, wherein 1/N of the first detection processing is performed at a first detection rate. a first detection step of acquiring partial detection data indicating whether or not the first pointer exists based on the 1/N process and storing the partial detection data in a memory; Each time the detection data is newly held in the memory, the N−1 partial detection data held in the memory so far and the newly held partial detection data are synthesized, and the predetermined a synthesizing step of generating overall detection data indicating whether or not the first pointer exists for the entire area of the pointer; and a reporting step of outputting the overall detection data at the first detection rate. position detection method.

A pointer position detection method according to still another aspect of the present invention is a pointer position detection method existing in a predetermined area, wherein the entire second detection process is executed at a second detection rate, a second detection step of performing detection of 2 pointers, performing 1/N processing of the first detection processing at a first detection rate, and detecting the second pointer based on the 1/N processing a first detection step of acquiring partial detection data indicating whether or not a different first pointer exists and holding it in a memory, wherein the second detection step and the first detection step is a pointer position detection method that is executed alternately.

A pointer position detection method according to still another aspect of the present invention is a pointer position detection method in a predetermined area including K first electrodes and K second electrodes, comprising: N×M pulse groups each consisting of K pulses are sequentially read out from the memory one pulse group at a time, and K pulses constituting the read pulse group are applied to the K first electrodes each time the reading is performed. a detection step of transmitting partial detection data to each of the K second electrodes and storing in the memory partial detection data indicating levels of signals output from each of the K second electrodes as a result of the transmission; each time the partial detection data corresponding to each of the pulse groups is stored in the memory, for each of the second electrodes, the (N−1)×M pulse groups that have been stored in the memory so far and a synthesizing step of synthesizing with the partial detection data corresponding to each of the above to generate synthesized detection data indicating whether or not the pointer exists on the corresponding second electrode. is.

Further, a pointer position detecting method according to still another aspect of the present invention is executed by a sensor controller connected to a sensor pattern, and detects the position of a passive pointer that does not transmit a signal and the pen electrode provided at the tip of the pointer. A pointer location detection method for detecting the position of an active pen configured to transmit and detecting the position of the passive pointer and determining a palm area by detecting changes in capacitance in the sensor pattern. a touch detection step; and a pen detection step of detecting a pen signal transmitted through the pen electrode and detecting a pen position, which is the position of the active pen, based on the level of the detected pen signal. , the pen detection step is performed by determining that (1) the previously detected pen position is within a predetermined area based on the palm area, and (2) the currently detected pen position and the previously obtained pen A pointer position detection method for outputting pen-up information indicating that the active pen has left the touch surface when the distance from the position exceeds a predetermined value.

Further, a pointer position detecting method according to still another aspect of the present invention is executed by a sensor controller connected to a sensor pattern, and detects the position of a passive pointer that does not transmit a signal and the pen electrode provided at the tip of the pointer. A pointer location detection method for detecting the position of an active pen configured to transmit and detecting the position of the passive pointer and determining a palm area by detecting changes in capacitance in the sensor pattern. a touch detection step of detecting a pen signal transmitted through the pen electrode, detecting a pen position, which is the position of the active pen, based on the level of the detected pen signal; and a pen detection step of detecting writing pressure based on the pen signal, wherein the pen detection step determines whether or not the pen position detected this time exists in the vicinity of the palm area, and determines that the pen position exists. In this case, if the pen pressure detected last time was invalid, the pen position detected this time is invalidated, and if the pen pressure detected last time was valid, the pen position detected this time is valid. This is a pointer position detection method.

According to the pointer position detection method of the present invention, one or more candidate touch positions to be output as the passive pointer position can be selected according to the active pen position held in the memory. It is possible to correctly identify the contact position of the

According to the pointer position detection method according to the present invention, the first detection process (passive pointer position detection process) is divided into N times and executed. Pen detection can be performed at regular intervals.

According to the pointer position detection method of the present invention, pen-up information can be output when the distance between the currently detected pen position and the previously detected pen position exceeds a predetermined value. It is possible to prevent unnecessary line segments from being drawn due to the presence of positions.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the usage condition of the position detection system 1 by the 1st Embodiment of this invention. FIG. 5 is a flowchart showing an overview of pointer position detection processing executed by a sensor controller provided in a position detector according to the background art of the present invention; 4 is a flowchart showing an overview of pointer position detection processing executed by the sensor controller 31 according to the embodiment of the present invention. FIG. FIG. 2 is a diagram showing a configuration of a tablet 3 shown in FIG. 1; FIG. 5 is a diagram showing the principle of position detection processing of the finger 4 executed by the MCU 40 shown in FIG. 4. FIG. (a) is a diagram showing a pen position table used in the output position determination process according to the embodiment of the present invention, and (b) is a touch table used in the output position determination process according to the embodiment of the present invention. It is a figure which shows a position table. 7 is a diagram showing an example of output position determination processing performed by the MCU 40 using the pen position table and the touch position table shown in FIG. 6; FIG. 7 is a diagram showing an example of output position determination processing performed by the MCU 40 using the pen position table and the touch position table shown in FIG. 6; FIG. 4 is a diagram showing details of the flow diagram shown in FIG. 3; FIG. 4 is a diagram showing details of the flow diagram shown in FIG. 3; FIG. FIG. 14 is a flowchart showing pointer position detection processing executed by a sensor controller 31 according to a fourth modification of the embodiment of the present invention. (a) is a diagram showing a control sequence for pointer position detection processing according to the background art of the present invention, and (b) is a diagram showing a control sequence for pointer position detection processing according to an embodiment of the present invention. is. FIG. 4 is a diagram showing an example of a finger detection signal FDS used with a 16×16 sensor 30; It is a figure which shows the 1st example of the content of the process of 1/N by embodiment of this invention. FIG. 10 is a diagram showing a second example of the contents of 1/N processing according to the embodiment of the present invention; FIG. 10 is a diagram showing a third example of the contents of 1/N processing according to the embodiment of the present invention; FIG. 10 is a diagram showing a fourth example of the content of 1/N processing according to the embodiment of the present invention; FIG. 12 is a diagram showing a fifth example of the content of 1/N processing according to the embodiment of the present invention; FIG. 14 is a diagram showing an example of specific storage contents of a shift register 40a in the fifth example; FIG. 14 is a diagram showing another example of specific storage contents of a shift register 40a in the fifth example; (a) is a diagram showing a control sequence relating to pointer position detection processing according to the first modification of the embodiment of the present invention, and (b) is a diagram showing the control sequence of the second modification of the embodiment of the present invention. and (c) is a diagram showing a control sequence for pointer position detection processing according to the third modification of the embodiment of the present invention. It is a figure which shows an example of the usage condition of the position detection system 1 by the 2nd Embodiment of this invention. It is a figure explaining operation|movement of the host processor 32 by the background art of the 2nd Embodiment of this invention. FIG. 10 is a flowchart showing pointer position detection processing executed by a sensor controller 31 according to the second embodiment of the present 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 an example of usage of a position detection system 1 according to the first embodiment of the present invention. As shown in the figure, a position detection system 1 according to this embodiment includes an active pen 2 and a tablet 3 . The tablet 3 has a touch surface 3a and is configured to detect the positions of the active pen and the passive pointer on the touch surface 3a. FIG. 1 shows how the tip of an active pen 2, the tip of a finger 4 as a passive pointer, and the user's hand 5 holding the active pen 2 are in contact with the touch surface 3a. Note that the user's finger 4 is shown as an example of a passive pointer, and any type of passive pointer does not matter in this embodiment. In the following description, the active pen 2 and the passive pointer represented by the finger 4 may be collectively referred to as "pointer".

Here, before describing the contents of the present embodiment in detail, the outline of the present invention will be described with reference to FIGS. 2 and 3. FIG.

First, FIG. 2 is a flowchart showing an overview of pointer position detection processing executed by a sensor controller (not shown) provided in a tablet according to the background art of the present invention. As shown in the figure, the sensor controller according to the background art of the present invention is configured to repeatedly execute the processes of steps S101 to S106 (step S100).

Specifically describing the processing of steps S101 to S106, the sensor controller first executes the position detection processing of the active pen 2 (step S101), and outputs the detected position to the host processor (not shown) (step S102). Subsequently, the position detection processing of the active pen 2 is executed again (step S103), and the detected position is output to the host processor (step S104). Next, the sensor controller executes position detection processing of the finger 4 (step S105), and outputs the detected position to the host processor (step S106).

The reason why the position detection processing of the active pen 2 is performed twice consecutively in steps S101 and S103 is to secure the detection rate of the active pen 2 as described above. However, by doing so, the detection interval of the active pen 2 is no longer constant. Therefore, as described above, for example, the coordinate data of the active pen 2 sequentially output from the sensor controller is transmitted at regular time intervals. In a drawing application that expects to operate, a problem arises that the drawing result becomes unnatural.

Further, as described above, the position detection processing of the active pen 2 has the problem that the contact position of the hand 5 may be erroneously detected as the position of the active pen. , the contact position of the active pen 2 or the hand 5 may be detected as the position of the finger 4 .

The processing performed by the sensor controller 31 (see FIG. 4 described later) provided in the tablet 3 according to this embodiment can solve these problems. The outline thereof will be described below with reference to FIG.

FIG. 3 is a flowchart showing an overview of pointer position detection processing executed by the sensor controller 31 . As shown in the figure, the sensor controller 31 is configured to repeatedly execute the processes of steps S2 to S9 (step S1). Among these, steps S2 to S4 are pen detection steps for detecting the pen position, which is the position of the active pen 2, and steps S5 to S9 are touch detection steps for detecting the passive pointer position, which is the position of the finger 4. is a step.

The processing of steps S2 to S9 will be specifically described in comparison with the processing shown in FIG. 2. First, the position detection processing itself of step S2 is the same as the position detection processing of step S101. However, the output processing of the detected position is different from step S102 of the background art. That is, the sensor controller 31 does not directly output the position detected in step S2 to the host processor 32 (see FIG. 4, which will be described later), but instead selects the pen position from one or more detected positions (candidate pen positions). A determination process (hereinafter referred to as "pen position determination process") is performed (step S3), and only the determined pen position is output to the host processor 32 (step S4). The specific contents of the pen position determination process will be described later, but since the contact position of the hand 5 can be excluded from the output targets in this process, the sensor controller 31 can correctly identify the contact position of the active pen 2. can.

Next, the sensor controller 31 performs the position detection process of the finger 4 in step S5, but in one process, only 1/N of the position detection process performed in step S105 is performed (step S5). . The specific contents of the 1/N processing will be described later, but since only 1/N processing is executed, the sensor controller 31 needs to combine the results of N times to obtain the position of the finger 4 . Therefore, the sensor controller 31 records the data indicating the partial detection result obtained by the 1/N processing (hereinafter referred to as “partial detection data”) (step S6), and stores the previously recorded N− It is configured to generate data indicating the position of the finger 4 (hereinafter referred to as "whole detection data") by synthesizing it with the partial detection data for one time (step S7). 1/N of the processing is completed in approximately 1/N of the time of the position detection processing executed in step S105. It is possible to secure the detection rate of the active pen 2 without continuously executing the position detection processing of the active pen 2 twice as in the example of .

After that, the sensor controller 31 performs a process of determining the passive pointer position from one or more positions (candidate touch positions) indicated by the overall detection data generated in step S7 (hereinafter referred to as "passive pointer position determination process"). (step S8), and outputs only the determined passive pointer position to the host processor 32 (step S9). The purpose of executing the processing of steps S8 and S9 is the same as that of steps S3 and S4. , the contact position of the finger 4 can be correctly identified. Specific contents of the passive pointer position determination process will also be described later. Hereinafter, pen position determination processing and passive pointer position determination processing may be collectively referred to as “output position determination processing”.

The outline of the present invention has been described above. Hereinafter, referring back to FIG. 1, the contents of the present embodiment will be described in detail. In the following, first, an overall overview of the configuration of the position detection system 1 according to the present embodiment will be described, and then detailed contents of the above-described output position determination processing and 1/N processing will be described in order.

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

A pen electrode is provided at the tip of the active pen 2, and the transmitting/receiving section of the active pen 2 connects this pen electrode and a sensor 30 (see FIG. 4 described later) provided on the touch surface 3a of the tablet 3. The uplink signal US is received and the downlink signal DS is transmitted via the capacitance formed therebetween. The pen electrode for receiving the uplink signal US and the pen electrode for transmitting the downlink signal DS may be different or the same.

The active pen 2 also includes a pen pressure detection unit that detects the pressure (pen pressure) applied to the pen tip, a side switch state detection unit that detects the on/off state of a side switch provided on the side, a pre-assigned unique ID and a power supply unit (battery) for supplying operating power to the active pen 2 . The control section of the active pen 2 is configured to be able to control these sections.

The downlink signal DS includes a position signal, which is a burst signal of a predetermined frequency, and a data signal including data to be transmitted from the active pen 2 to the tablet 3 . The position signal is used in tablet 3 to detect the position of active pen 2 . The data transmitted by the data signal includes, for example, data indicating the pen pressure detected by the pen pressure detection unit (pen pressure data), and data indicating the ON/OFF state of the side switch acquired by the side switch state detection unit (switch data). , a unique ID stored in the storage unit, etc., and placed in the data signal by the control unit.

The uplink signal US includes a predetermined start bit and a command indicating instructions from the tablet 3 to the active pen 2 . The control unit of the active pen 2 is arranged to extract and decode the command from the received uplink signal US and place the data according to its content into the data signal. This allows the tablet 3 to retrieve desired data from the active pen 2 .

The tablet 3 is an electronic device that has both a function as a liquid crystal display device and a function as a position detector that detects the position of the pointer on the touch surface 3a. The touch surface 3a is provided on a liquid crystal display screen. Further, pointers detectable by the tablet 3 include both the active pen 2 and the finger 4 shown in FIG.

Although details will be described later with reference to FIG. 4, a sensor 30 including a plurality of sensor electrodes 30X and 30Y (sensor pattern) is provided inside the touch surface 3a. The tablet 3 detects the position of the finger 4 (passive pointer position) by detecting changes in the capacitance of this sensor 30, and detects the position of the active pen 2 (pen position) by detecting the position signal described above with the sensor 30. ) is configured to detect

Each sensor electrode 30X also serves as a common electrode of the liquid crystal display device, and a pixel driving voltage Vcom, which is a fixed potential, is supplied to each sensor electrode 30X during a pixel driving operation. Such a type of tablet 3 that uses the sensor electrode for position detection also as an electrode for liquid crystal display is generally called an "in-cell type". In the "in-cell type" tablet 3, the sensor electrode 30X cannot be used for position detection during the pixel drive operation. and vertical blanking interval). However, the present invention is similarly applicable to a type of tablet (non-in-cell type) in which the plurality of sensor electrodes 30X and 30Y are independent of the electrodes (common electrode and pixel electrode) of the liquid crystal display device. .

FIG. 4 is a diagram showing the configuration of the tablet 3. As shown in FIG. As shown in the figure, the tablet 3 includes a sensor 30 , a sensor controller 31 and a host processor 32 .

The sensor 30 includes a plurality of sensor electrodes 30X each extending in the Y direction and arranged at equal intervals in the X direction orthogonal to the Y direction, and a plurality of sensor electrodes 30X each extending in the X direction and arranged at equal intervals in the Y direction. It has a configuration in which a plurality of sensor electrodes 30Y are arranged in a matrix. Although an example in which both the sensor electrodes 30X and 30Y are composed of linear conductors is shown here, the sensor electrodes 30X and 30Y can be composed of conductors of other shapes. For example, one of the sensor electrodes 30X and 30Y may be composed of a plurality of rectangular conductors arranged two-dimensionally so that the two-dimensional coordinates of the active pen 2 can be detected.

The sensor controller 31 is configured to perform communication with the active pen 2 (including detection of the position of the active pen 2) and detection of the position of the finger 4 using the sensor 30 in a time-sharing manner at intervals of the pixel driving operation. be. Further, during the pixel driving operation, the pixel driving voltage Vcom is configured to be supplied to each of the plurality of sensor electrodes 30X. The configuration of the sensor controller 31 will be described in more detail below.

The sensor controller 31 includes an MCU 40, a logic section 41, transmission sections 42 and 43, a reception section 44, and a selection section 45, as shown in FIG.

The MCU 40 and the logic unit 41 are control units that control transmission/reception operations of the sensor controller 31 by controlling the transmission units 42 and 43 , the reception unit 44 and the selection unit 45 . Specifically, the MCU 60 is a microprocessor that has internal memory (ROM and RAM) and operates by executing a program stored in this memory. Operation timing of the MCU 40 is controlled by a timing signal supplied from the host processor 32 . The operations performed by the MCU 40 include the control operation of the logic unit 41, the operation of supplying the pixel driving voltage Vcom to the selection unit 45, the operation of controlling the transmission unit 42 to output the finger detection signal FDS, and the active operation. The operation of supplying the command COM indicating the content of the instruction to the pen 2 to the transmission unit 43, and the positions of the active pen 2 and the finger 4 (specifically, the touch surface 3a) based on the digital signal supplied from the reception unit 44 Data Res transmitted by the active pen 2 (for example, the above-mentioned writing pressure data, switch data , or a unique ID), and an operation of determining the state of contact of the active pen 2 with the touch surface 3a based on the writing pressure data included in the data Res. The logic unit 41 has a function of outputting control signals ctrl_t1 to ctrl_t4 and ctrl_r under the control of the MCU40.

The transmission section 42 is a circuit that generates a finger detection signal FDS under the control of the MCU 40 and supplies it to each sensor electrode 30X through the selection section 45 . Here, specific contents of the finger detection signal FDS and a method of supplying it to each sensor electrode 30X will be described with reference to FIG.

FIG. 5 is a diagram showing the principle of position detection processing of the finger 4 executed by the MCU 40. As shown in FIG. This figure shows the state before the position detection processing of the finger 4 is divided into the 1/N processing shown in FIG. 3, that is, the position detection processing of the finger 4 executed in step S105 shown in FIG. there is For the sake of simplicity, only four sensor electrodes 30X are shown in the figure, but actually more sensor electrodes 30X are arranged. In the following description, it is assumed that the number of sensor electrodes 30X is K. As shown in FIG.

As shown in FIG. 5, the finger detection signal FDS is composed of, for example, K signals s ₁ to s _K each composed of K pulses represented by “1” or “−1”. The n-th (n=1 to K) pulses of each of the signals s ₁ to s _K constitute a pulse group p _n , and each pulse constituting one pulse group p _n is transmitted from the transmitter 42 shown in FIG. It is input in parallel to each sensor electrode 30X through the selection unit 45 .

Return to FIG. The transmission unit 43 is a circuit that generates an uplink signal US under the control of the MCU 40 and the logic unit 41 and supplies it to the selection unit 45. As shown in the figure, the pattern supply unit 50, the switch 51, and the code string holding unit. 52, a spreading processing unit 53, and a transmission guard unit . Among them, the pattern supply unit 50 in particular is described as being included in the transmitting unit 43 in this embodiment, but may be included in the MCU 40 .

The pattern supply unit 50 holds the start bit SB arranged at the head of the uplink signal US, and outputs the held start bit SB according to the instruction of the control signal ctrl_t1 supplied from the logic unit 41. Configured.

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

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

The spreading processing unit 53 modulates the spreading code held by the code string holding unit 52 based on the value (start bit SB or command COM) supplied via the switch 51, thereby generating a transmission chip string having a predetermined chip length. has a function to obtain The spreading processing unit 53 supplies the acquired transmission chip sequence to the selection unit 45 via the transmission guard unit 54 .

The transmission guard unit 54 is required to switch between the transmission operation and the reception operation between the transmission period of the uplink signal US and the reception period of the downlink signal DS based on the control signal ctrl_t4 supplied from the logic unit 41. It has a function to insert a guard period (a period during which neither transmission nor reception is performed).

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

The switch 58y is a switch element configured such that the common terminal is connected to either one of the T terminal and the R terminal. The switch 58 y has a common terminal connected to the conductor selection circuit 59 y , a T terminal connected to the output terminal of the transmitter 43 , and an R terminal connected to the input terminal of the receiver 44 . Also, the switch 58x is a switch element configured such that the common terminal is connected to any one of the T1 terminal, T2 terminal, D terminal, and R terminal. Among them, the T2 terminal is actually a set of terminals corresponding to the number of the sensor electrodes 30X. The common terminal of the switch 58x is connected to the conductor selection circuit 59x, the T1 terminal is connected to the output terminal of the transmitter 43, the T2 terminal is connected to the output terminal of the transmitter 42, and the D terminal outputs the pixel driving voltage Vcom. The R terminal is connected to the input terminal of the receiving section 44 .

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

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

The selector 45 is supplied with four control signals sTRx, sTRy, selX, and selY from the logic unit 41 . Specifically, the control signal sTRx is supplied to the switch 58x, the control signal sTRy to the switch 58y, the control signal selX to the conductor selection circuit 59x, and the control signal selY to the conductor selection circuit 59y. The logic unit 41 controls the selection unit 45 using these control signals sTRx, sTRy, selX, and selY to transmit the uplink signal US or the finger detection signal FDS, apply the pixel driving voltage Vcom, Reception of the link signal DS or the finger detection signal FDS is realized.

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

Next, at the timing of receiving the position signal described above out of the downlink signal DS, the logic unit 41 sequentially selects the plurality of sensor electrodes 30X and 30Y one by one. The selection unit 45 is controlled so as to be connected. As a result, position signals equal in number to the number of sensor electrodes 30X and 30Y are sequentially supplied to the receiving section 44. FIG. Although details will be described later, the MCU 40 is configured to detect the position of the active pen 2 based on the level of the position signal supplied to the receiving section 44 in this way.

Specifically, the MCU 40 determines the level of the position signal at each intersection of the plurality of sensor electrodes 30X and 30Y based on the digital signal (described later) supplied from the receiver 44. FIG. Then, the position of the active pen 2 is detected based on each determined level. Specifically, a region within the touch surface 3a in which the level of the position signal is equal to or higher than a predetermined value may be determined, and the center position thereof may be detected as the position of the active pen 2, for example.

At the timing of receiving the above-described data signal in the downlink signal DS, the MCU 40 first selects one or more of the plurality of sensor electrodes 30X and 30Y. This selection is performed based on the position of the active pen 2 detected based on the previous position signal. The logic unit 41 then controls the selection unit 45 so that the selected sensor electrodes 30X and 30Y are connected to the reception unit 44 . This makes it possible to supply the data signal transmitted by the active pen 2 to the receiving section 44 .

Next, at the timing of transmitting the finger detection signal FDS, the logic unit 41 selects one sensor electrode 30Y together with the MCU 40, and sends the above-described pulse groups p ₁ to p _K to the transmitting unit 42 sequentially to each sensor electrode 30X. Input is repeated for each sensor electrode 30Y. Specifically, the logic unit 41 first controls the selection unit 45 so that the plurality of terminals constituting the T2 terminal of the switch 58x and the plurality of sensor electrodes 30X are connected one-to-one. Then, while maintaining this state, the selection unit 45 is controlled such that the plurality of sensor electrodes 30Y are sequentially selected one by one and the selected sensor electrodes 30Y are connected to the reception unit 44 .

Further, while selecting one sensor electrode 30Y, the MCU 40 sequentially reads out the pulse groups p ₁ to p _K from the memory one pulse group at a time. A pulse is supplied to the transmitter 42 . The transmitter 42 inputs the K pulses thus supplied to the K sensor electrodes 30X in parallel. As a result of such control, the level of the digital signal supplied from the receiving section 44 reflects changes in the capacitance formed at the intersections of the selected sensor electrode 30Y and each sensor electrode 30X. Therefore, MCU 40 is configured to detect the position of finger 4 based on the level of the digital signal supplied from receiving section 44 .

Here, referring to FIG. 5 again, the position detection processing of the finger 4 executed by the MCU 40 will be described in more detail. In the following description, the number of sensor electrodes 30X is four (that is, K=4), but the same applies to cases where the number of sensor electrodes 30X is three or less or five or more.

When the number of sensor electrodes 30X is four, each of the signals s ₁ to s _K is composed of four pulses represented by "1" or "-1". Specifically, as shown in FIG. 5, the signal s1 is " ₁ , 1, 1, 1", the signal s2 is " ₁ , ₁ , -1, -1", and the signal s3 is "1, - 1,-1,1", and the signal s4 is composed of " _1-1,1 ,-1" respectively.

The MCU 40 functionally includes a shift register 40a and a correlator 40b. The shift register 40a is a FIFO storage unit, and is configured to be able to store the same number of data as the number of sensor electrodes 30X (that is, K data). When new data is stored in the shift register 40a, the data stored K times before is erased. As described above, the MCU 40 and the logic unit 41 select one sensor electrode 30Y and cause the transmission unit 42 to sequentially input the pulse groups p ₁ to p ₄ to each sensor electrode 30X. repeat. As a result, four levels L ₁ to L ₄ respectively corresponding to the pulse groups p ₁ to p ₄ appear sequentially on the selected sensor electrode 30Y. The MCU 40 sequentially acquires the levels L ₁ to L ₄ appearing on the sensor electrode 30Y through the receiving section 44 and stores them in the shift register 40a each time.

Specific contents of the levels L ₁ to L ₄ will be described in detail, taking as an example the case where the sensor electrode 30Y ₁ shown in FIG. 5 is selected. In the following description, the capacitances formed between the sensor electrode 30Y ₁ and each of the four sensor electrodes 30X ₁ to 30X ₄ are C ₁₁ to C ₄₁ respectively.

First, the level L ₁ stored in the shift register 40a corresponding to the pulse group p ₁ consists of a capacitance vector (C ₁₁ , C ₂₁ , C ₃₁ , C ₄₁ ) and a vector ( ₁ , 1 , 1, 1). This inner product is calculated as C ₁₁ +C ₂₁ +C ₃₁ +C ₄₁ as also shown in FIG. Similarly, the level L2 stored in the shift register 40a corresponding to the pulse group p2 is a vector of capacitances _{( C11} , _C21 , _C31 , _C41 ) and _a vector ( ₁ , ₁ , -1 _, -1) and calculated as C ₁₁ +C ₂₁ -C ₃₁ -C ₄₁ . vector (C ₁₁ , C ₂₁ , C ₃₁ , C ₄₁ ) and vector (1, −1, −1, 1) representing pulse group p ₃ , resulting in the inner product of C ₁₁ −C ₂₁ −C ₃₁ +C ₄₁ and stored in shift register 40a corresponding to pulse group _p4 is a vector of capacitances _{( C11} , _C21 , _C31 , _C41 ) and a vector indicating pulse group _p4 . C ₁₁ −C ₂₁ +C ₃₁ −C ₄₁ is calculated as an inner product with (1, −1, 1, −1).

The MCU 40 uses the correlator 40b to sequentially calculate correlation values T ₁ to T ₄ with the levels L ₁ to L ₄ stored in the shift register 40a for each of the four pulse groups p ₁ to p ₄ . Specific contents of the correlation values T ₁ to T ₄ thus calculated are 4C ₁₁ , 4C ₂₁ , 4C ₃₁ and 4C ₄₁ respectively, as shown in FIG. That is, the correlation values T ₁ to T ₄ reflect changes in the capacitance formed at the intersections of the sensor electrodes 30X ₁ to 30X ₄ and the sensor electrode 30Y ₁ . Therefore, the MCU 40 can detect the position of the finger 4 by referring to the correlation values T ₁ to T ₄ calculated for each sensor electrode 30Y. Specifically, a region within the touch surface 3a in which the change in capacitance is equal to or greater than a predetermined value is determined, and the center position thereof may be detected as the position of the finger 4, for example.

The position detection processing of the finger 4 executed by the MCU 40 has been described in detail above. Next, returning to FIG. 4, the logic unit 41 controls the switch 58x so that the D terminal is connected to the common terminal at the timing of applying the pixel driving voltage Vcom. Thereby, the pixel driving voltage Vcom is supplied to each of the plurality of sensor electrodes 30X, and the pixel driving operation can be performed.

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

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

The MCU 40 detects the positions (coordinates x, y) of the finger 4 and the active pen 2 and acquires the data Res transmitted by the active pen 2 based on the digital signals thus supplied. Specifically, regarding the position of the finger 4, the MCU 40 obtains levels L ₁ to L _K corresponding to the pulse groups p ₁ to p _K for each sensor electrode 30Y based on the supplied digital signal. do. The method of detecting the position of the finger 4 from the levels L ₁ to L _K is as described above with reference to FIG. Next, regarding the position of the active pen 2, the MCU 40 determines the level of the position signal at each intersection of the plurality of sensor electrodes 30X and 30Y based on the supplied digital signal, as described above, and based on each determined level to detect the position of the active pen 2. Finally, regarding the data Res, the MCU 40 acquires the data Res by decoding the digital signal supplied from the receiver 44 . The MCU 40 is configured to output the thus detected position (coordinates x, y) and data Res to the host processor 32 .

Further, the MCU 40 determines the contact state of the active pen 2 with respect to the touch surface 3a based on the writing pressure data included in the acquired data Res, and when it determines that the active pen 2 newly contacts the touch surface 3a ( That is, when the writing pressure changes from 0 to a positive value), the pen-down information IN-PROXY is output to the host processor 32, and when it is determined that the active pen 2 has left the touch surface 3a (that is, when the writing pressure changes from a positive value to 0), it is configured to output pen-up information OUT-PROXY to the host processor 32 . The output pen-down information IN-PROXY and pen-up information OUT-PROXY are used by the host processor 32 to recognize the beginning and end of strokes.

The above is the outline of the configuration of the position detection system 1 according to the present embodiment. Next, detailed contents of the above-described output position determination processing and 1/N processing will be described in order.

First, the output position determination process will be described in detail.

FIG. 6(a) is a diagram showing a pen position table used in the output position determination process according to this embodiment, and FIG. 6(b) shows a touch table used in the output position determination process according to this embodiment. It is a figure which shows a position table. MCU 40 uses these tables to determine the positions to output to host processor 32 after detecting one or more positions for each active pen 2 or finger 4 by the processes described above.

The pen position table, as shown in FIG. 6A, is a table that associates and stores candidate pen positions cP[i], fixed pen positions fP[i], and valid flags. On the other hand, the touch position table is a table that associates and stores candidate touch positions cT[j], confirmed touch positions fT[j], valid flags, and area types. However, i and j are each an integer of 0 or more. The candidate pen position cP[i] is the position of the active pen 2 detected in step S2 of FIG. 3, and the candidate touch position cT[j] is based on the overall detection data generated in step S7 of FIG. Position of finger 4 shown. Other parameters are described in the description below.

Here, before specifically describing the contents of the output position determination process, the concept of this process will be described in detail with reference to FIG. 1 again.

In the example shown in FIG. 1, three types of objects, the active pen 2, the finger 4, and the hand 5 holding the active pen 2, are in contact with the touch surface 3a. In the process of detecting the position of the finger 4, it is originally preferable to detect only the finger 4, but there is a possibility that the active pen 2 and the hand 5 will also be detected. This is because changes in capacitance at sensor electrodes 30X, 30Y may include changes in capacitance at sensor electrodes 30X, 30Y due to capacitance formed between active pen 2 or hand 5 and sensor electrodes 30X, 30Y. On the other hand, in the process of detecting the position of the active pen 2, although it is preferable that only the active pen 2 is detected, there is a possibility that the hand 5 will also be detected. This is not only the route from the tip of the active pen 2 to the touch surface 3a (arrow A in FIG. 1), but also the route via the hand 5 (arrow B in FIG. 1). This is because the downlink signal DS is transmitted to the .

After acquiring one or more candidate touch positions by the processing shown in steps S5 to S7 in FIG. 3 (or the processing shown in step S105 in FIG. 2), the MCU 40 first determines the width of each candidate touch position (capacitance The width of the area where the amount of change is equal to or greater than a predetermined amount) is determined. Then, the candidate touch positions whose determined width is equal to or larger than the predetermined size are excluded from the output targets. In the example of FIG. 1, the contact position of the hand 5 is excluded here. Next, for each of the remaining candidate touch positions, the pen position table is referenced to determine whether or not the position of the active pen 2 was detected in the previous position detection process of the active pen 2, and the detected candidate touch position is determined. Exclude the touch position from the output target. In the example of FIG. 1, the contact position of the active pen 2 is excluded here. The remaining candidate touch positions are the positions output to the host processor 32 in step S9 of FIG. According to this, since the contact position of the hand 5 and the contact position of the active pen 2 are excluded from the output targets, it is possible to select and output only the position of the finger 4 correctly.

On the other hand, after acquiring one or more candidate pen positions by the process shown in step S2 in FIG. is detected as the position of the finger 4 or the hand 5 in the position detection process. Then, the candidate pen position determined to have been detected as the position of the hand 5 is excluded from the output targets. In the example of FIG. 1, the contact position of the hand 5 is excluded here. The candidate pen positions not excluded here, that is, the candidate pen positions determined not to be detected and the candidate pen positions determined to have been detected as the finger 4 are output to the host processor 32 in step S4 of FIG. position. According to this, since the contact position of the hand 5 is excluded from the output targets, it is possible to correctly select and output only the position of the active pen 2 .

As described above, according to the position detection processing according to the present embodiment, it is possible to correctly select the positions of the active pen 2 and the finger 4 and output them to the host processor 32 . Specific contents of output position determination processing performed by the MCU 40 using the pen position table and the touch position table will be described in detail below.

7 and 8 are diagrams showing examples of output position determination processing performed by the MCU 40 using the pen position table and the touch position table, respectively.

FIG. 7 shows an example of changes in the pen position table and the touch position table when the position detection of the active pen 2 precedes in chronological order. The MCU 40 according to this example stores two candidate pen positions cP[0] and cP[1] in the pen position candidate table as a result of the first position detection processing of the active pen 2 . Then, the candidate pen positions cP[0] and cP[1] are set to the corresponding fixed pen positions fP[0] and fP[1], respectively, and the respective effective flags are set to "effective". The MCU 40 supplies each of the confirmed pen positions fP[0] and fP[1] set to "valid" to the host processor 32 as the detection position of the active pen 2. FIG. However, the detected position may not be supplied to the host processor 32 at this stage.

Next, the MCU 40 performs the first position detection process of the finger 4, and as a result stores three candidate touch positions cT[0] to cT[2] in the touch position candidate table. First, the width of each of the candidate touch positions cT[0] to cT[2] (the width of the area where the amount of change in capacitance is equal to or greater than a predetermined amount) is detected. Here, assuming that a width equal to or larger than a predetermined size is detected only for the candidate touch position cT[1], and widths smaller than the predetermined size are detected for the other candidate touch positions cT[0] and cT[2], The MCU 40 sets the candidate touch position cT[1] to the confirmed touch position fT[1], sets the corresponding valid flag to "invalid", and further sets the corresponding area type to "palm". do.

Next, the MCU 40 selects the determined pen positions fP[0] and fP[1 stored in the pen position candidate table for the candidate touch positions cT[0] and cT[2] detected to be less than the predetermined size. ] are substantially equal to each other. Here, "substantially equal" means that the distance between one position and the other position is less than or equal to a predetermined value which is sufficiently small compared to the width of the touch surface 3a. A specific value of this predetermined value is preferably, for example, a length of several pixels.

In the example of FIG. 7, the candidate touch position cT[0] is determined to be substantially equal to the confirmed pen position fP[0], and the candidate touch position cT[2] is either the confirmed pen position fP[0] or fP[1]. are determined to be unequal. In this case, the MCU 40 sets the candidate touch position cT[2] to the confirmed pen position fP[2], sets the corresponding valid flag to "valid", and further sets the corresponding area type to "finger". On the other hand, nothing is set to the fixed pen position fP[0] (the initial value is NULL), and the corresponding valid flag is set to "invalid". The area type corresponding to the fixed pen position fP[0] is left as the initial value (nothing is set).

After setting the touch position candidate table as described above, the MCU 40 supplies only the confirmed touch position fT[2] whose corresponding validity flag is "valid" to the host processor 32 as the detected position of the finger 4. do. A candidate touch position cT[0] that is located near the fixed pen position fP[0] and whose detected width is less than the predetermined size is not supplied to the host processor 32 .

Next, the MCU 40 resets the pen position candidate table once, and then performs the position detection processing of the active pen 2 for the second time. Here, assuming that none of the active pen 2, the finger 4, and the hand 5 are moving on the touch surface 3a, as a result of position detection, two candidate pen positions cP[0] and cP[1 ] is stored in the pen position candidate table.

Then, the MCU 40 determines whether each of the acquired candidate pen positions cP[0] and cP[1] is substantially equal to each of the confirmed touch positions fT[0] to fT[2] stored in the touch position candidate table. determine whether In the example of FIG. 7, since NULL is set to the confirmed touch position fT[0] at this point, it is substantially equal to each of the confirmed touch positions fT[1] and fT[2]. It will be a judgment of whether.

In the example of FIG. 7, the candidate pen position cP[1] is determined to be approximately equal to the confirmed touch position fT[1], and the candidate pen position cP[0] is any of the confirmed touch positions fT[0] to fT[2]. are determined to be unequal. In this case, the MCU 40 first sets the candidate pen position cP[0] to the fixed pen position fP[0] and sets the corresponding valid flag to "valid". On the other hand, for the candidate pen position cP[1], it is determined whether the region type of the corresponding confirmed touch position fT[1] is "palm" or "finger". If the determination result is "palm", NULL is set to the fixed pen position fP[1], and the corresponding valid flag is set to "invalid". On the other hand, if the determination result is "finger", the candidate pen position cP[1] is set to the fixed pen position fP[1], and the corresponding valid flag is set to "valid". In the example of FIG. 7, the area type of the confirmed touch position fT[1] is "palm", so NULL is set to the corresponding confirmed pen position fP[1].

FIG. 8 shows an example of changes in the pen position table and the touch position table when the position detection of the finger 4 precedes, in chronological order. The MCU 40 according to this example stores three candidate touch positions cT[0] to cT[2] in the touch position candidate table as a result of performing the position detection processing of the finger 4 for the first time. Subsequently, the MCU 40 detects the width of each of the candidate touch positions cT[0] to cT[2] (the width of the area where the amount of change in capacitance is equal to or greater than a predetermined amount). Here, as in the example of FIG. 7, assuming that only the candidate touch position cT[1] is detected to be wider than the predetermined size, the MCU 40 first places the candidate touch position cT[1] at the confirmed touch position fT[1]. While setting, the corresponding valid flag is set to "invalid", and the corresponding area type is set to "palm". On the other hand, for the other two candidate touch positions cT[0] and cT[2], the candidate touch positions cT[0] and cT[2] are set to the confirmed touch positions fT[0] and fT[2], respectively. Also, the corresponding valid flag is set to "valid", and the corresponding area type is set to "finger". The MCU 40 supplies each of the confirmed touch positions fT[0] and fT[2] for which "valid" is set to the host processor 32 as the detection position of the finger 4. FIG. However, the detected position may not be supplied to the host processor 32 at this stage.

Next, the MCU 40 performs the first position detection process of the active pen 2 and, as a result, stores two candidate pen positions cP[0] and cP[1] in the pen position candidate table. Then, the MCU 40 determines whether each of the acquired candidate pen positions cP[0] and cP[1] is substantially equal to each of the confirmed pen positions fT[0] to fT[2] stored in the touch position candidate table. determine whether

In the example of FIG. 8, the candidate pen position cP[0] is determined to be approximately equal to the confirmed touch position fT[0], and the candidate pen position cP[1] is determined to be substantially equal to the confirmed touch position fT[1]. It will be. Next, the MCU 40 determines whether the area type of each of the confirmed touch positions fT[0] and fT[1] is "palm" or "finger". In the example of FIG. 8, the area type of the confirmed touch position fT[0] is determined to be "finger", and the area type of the confirmed touch position fT[1] is determined to be "palm".

The MCU 40 sets NULL to the confirmed pen position fP[1] for the candidate pen position cP[1] for which the area type of the corresponding confirmed touch position fT[1] is determined to be "palm", and Set the flag to "disabled". On the other hand, for the candidate pen position cP[0] for which the area type of the corresponding confirmed touch position fT[0] is determined to be "finger", the candidate pen position cP[0] is set to the confirmed pen position fP[0]. At the same time, the corresponding valid flag is set to "valid". This processing means that it is assumed that there is an error in the position detection processing of the finger 4 . The MCU 40 supplies the determined pen position fP[0] set to “valid” to the host processor 32 as the detected position of the active pen 2 .

Next, the MCU 40 resets the touch position candidate table once, and then performs the position detection processing of the finger 4 for the second time. Here, assuming that none of the active pen 2, finger 4, and hand 5 is moving on the touch surface 3a, as a result of position detection, three candidate touch positions cT[0] to cT[2 ] is stored in the touch position candidate table.

After storing the candidate touch positions cT[0] to cT[2] in the touch position candidate table, the MCU 40 next determines the width of each of the candidate touch positions cT[0] to cT[2] (the amount of capacitance change is a predetermined amount). The width of the area that is above is detected. Here, as in the first detection, assuming that only the candidate touch position cT[1] is detected to be wider than a predetermined size, the candidate touch position cT[1] is set to the confirmed touch position fT[1]. while setting the corresponding valid flag to "invalid" and further setting the corresponding area type to "palm". This processing is the same as the processing performed after the position detection of the finger 4 for the first time.

Next, the MCU 40 determines whether the remaining candidate touch positions cT[0] and cT[2] are substantially equal to the final pen positions fP[0] and fP[1] stored in the pen position candidate table. determine whether In the example of FIG. 8, this determination determines that the candidate touch position cT[0] is substantially equal to the confirmed pen position fP[0], and the candidate touch position cT[2] 1]. In this case, the MCU 40 sets the candidate touch position cT[2] to the confirmed pen position fP[2], sets the corresponding valid flag to "valid", and further sets the corresponding area type to "finger". On the other hand, nothing is set to the fixed pen position fP[0] (the initial value is NULL), and the corresponding valid flag is set to "invalid". The area type corresponding to the fixed pen position fP[0] is left as the initial value (nothing is set).

After setting the touch position candidate table as described above, the MCU 40 supplies only the confirmed touch position fT[2] whose corresponding validity flag is "valid" to the host processor 32 as the detected position of the finger 4. do.

As described above, according to the output position determination process according to the present embodiment, the contact position of the hand 5 can be excluded from the output target in the pen position determination process, and the active pointer position determination process can be performed in the passive pointer position determination process. The contact positions of the pen 2 and the hand 5 can be excluded from the output targets. Therefore, even if the contact position of the active pen 2 and the contact position of the finger 4 are mutually erroneously recognized at the stage of the candidate pen position and the candidate touch position, the active pen 2 and the finger 4 are finally recognized. This allows the position to be correctly output to host processor 32 .

Next, referring to the processing flow of the MCU 40, the output position determination processing performed by the MCU 40 using the pen position table and the touch position table will be described in more detail again from another point of view.

9 and 10 are diagrams showing details of the flow diagram shown in FIG. Referring first to FIG. 9, the MCU 40 first performs detection of the active pen 2 (step S21), and as a result determines whether or not the active pen 2 is detected (step S22). The process of step S2 shown is executed. If it is determined in step S22 that the finger 4 has not been detected, the process proceeds to step S51 in FIG. 10 and the position detection processing of the finger 4 is started.

On the other hand, if it is determined in step S22 that it has been detected, the MCU 40 executes the pen position determining process shown in step S3 of FIG. Specifically, first, the pen position table is reset (step S31). The pen position table after reset is in a state in which not even one candidate pen position cP[i] is set. Subsequently, the MCU 40 acquires I (I is an integer equal to or greater than 1) candidate pen positions cP[i] (i=0 to I−1) detected in step S21, and sets them in the pen position table ( step S32). Then, the processes of steps S34 to S36 are sequentially performed for all i (step S33).

More specifically, the MCU 40 first determines whether or not a final touch position fT[j] equal to the candidate pen position cP[i] is stored in the touch position table (step S34). As a result, if it is determined that it is stored, the area type stored in the touch position table for the final touch position fT[j] substantially equal to the candidate pen position cP[i] is "finger" or "palm". It is determined which one it is (step S35).

When it is determined in step S34 that it is not stored, and when it is determined in step S35 that it is a "finger", the MCU 40 sets the final pen position fP[i] to the candidate pen position cP[i], "Valid" is set to the corresponding valid flag (step S36). On the other hand, if it is determined to be "palm" in step S35, the processing of step S36 is not performed, and as a result, the corresponding fixed pen position fP[i] is NULL and the corresponding valid flag is "invalid". set respectively.

When the processing of steps S34 to S36 is completed for all i, the MCU 40 sends only the confirmed pen positions fP[i] whose corresponding valid flags are "valid" to the host processor 32 as detected positions of the active pen 2. output (step S4), and then the position detection processing of the finger 4 is started.

Specifically, as shown in FIG. 10, the detection of the finger 4 is executed (step S51), and as a result, it is determined whether or not the finger 4 has been detected (step S52). The processing of steps S5 to S7 is executed. Although the processes of steps S5 to S7 are executed here, the process of step S105 in FIG. 2 may be executed. However, in this case, in order to secure the detection rate of the active pen 2, it is necessary to perform the processing of steps S2 to S4 twice consecutively. If it is determined in step S52 that the position of the active pen 2 has not been detected, the process proceeds to step S21 of FIG.

On the other hand, if it is determined in step S52 that the pointer is detected, the MCU 40 executes the passive pointer position determining process shown in step S8 of FIG. Specifically, first, the touch position table is reset (step S81). The touch position table after reset is in a state in which not even one candidate touch position cT[j] is set. Subsequently, the MCU 40 acquires J (J is an integer equal to or greater than 1) candidate touch positions cT[j] (j=0 to J−1) detected in step S51, and sets them in the touch position table ( step S82). Then, the processes of steps S84 to S87 are sequentially performed for all j (step S83).

Specifically, the MCU 40 first calculates the area of the candidate touch position cT[j]. The area calculated here is the area of the region that includes the candidate touch position cT[j] and the amount of capacitance change is equal to or greater than a predetermined amount. Then, it is determined whether or not the calculated area is equal to or greater than a predetermined size (step S84).

If it is determined in step S84 that the size is equal to or larger than the predetermined size (that is, if it is determined that the area is large), the MCU 40 sets the confirmed touch position fT[j] to the candidate touch position cT[j], and also sets the candidate touch position cT[j]. "Invalid" is set to the valid flag to be displayed, and "Palm" is set to the corresponding area type (step S85).

On the other hand, if it is determined in step S84 that the size is not equal to or larger than the predetermined size (that is, if it is determined that the area is small), the MCU 40 subsequently determines that the determined pen position fP[i] substantially equal to the candidate touch position cT[j] is It is determined whether or not it is stored in the pen position table (step S86). As a result, when it is determined that it is not stored, the MCU 40 sets the candidate touch position cT[j] to the confirmed touch position fT[j], sets the corresponding valid flag to "valid", and sets the corresponding area type to "valid". "finger" is set (step S87). On the other hand, if it is determined in step S86 that it is stored, the MCU 40 does not perform the processing of step S87, and as a result, the corresponding confirmed touch position fT[j] is NULL and the corresponding valid flag is "invalid". set respectively.

When the processing of steps S15 to S18 is completed for all i, the MCU 40 outputs to the host processor 32 only the confirmed touch position fT[j] whose corresponding valid flag is "valid" as the detected position of the finger 4. (step S9), and then the process returns to step S2 to start the position detection processing of the active pen 2. FIG.

As above, the output position determination processing performed by the MCU 40 using the pen position table and the touch position table has been described in more detail again with reference to the processing flow of the MCU 40 . Here, various modifications are conceivable for the output position determination processing according to the present embodiment. Therefore, hereinafter, as modifications of the output position determination process according to the present embodiment, first to fourth modifications will be described.

A first modification relates to pen position determination processing. When a plurality of positions where the level of the downlink signal DS is equal to or higher than a predetermined level are detected, the MCU 40 according to this modification sends the position where the level of the downlink signal DS is the highest as the position of the active pen 2 to the host processor 32. configured to output In the example of FIG. 7, the level of the downlink signal DS at the candidate pen position cP[1] detected by the downlink signal DS received through the user's hand 5 is typically directly from the pen electrode of the active pen 2. It will be smaller than the level of the downlink signal DS at the candidate pen position cP[0] detected by the received downlink signal DS. Therefore, the MCU 40 will output the candidate pen position cP[0] to the host processor 32 as the position of the active pen 2 . This result is the same as that according to the above embodiment. Therefore, it can be said that the MCU 40 can correctly output the position of the active pen 2 to the host processor 32 also in this modified example.

The second modification also relates to pen position determination processing. In the MCU 40 according to this modification, when a plurality of positions where the level of the downlink signal DS is equal to or higher than a predetermined level are detected apart, the area of the region where the level of the downlink signal DS equal to or higher than the predetermined level is continuous is configured to detect the position of the active pen 2 based on. More specifically, the position with the smaller area is detected as the position of the active pen 2 . In the example of FIG. 7, the area over the candidate pen position cP[1] detected by the downlink signal DS received through the user's hand 5 is the downlink received directly from the pen electrode of the active pen 2. This area is larger than the above area for the candidate pen position cP[0] detected by the signal DS. Therefore, the MCU 40 will output the candidate pen position cP[0] to the host processor 32 as the position of the active pen 2 . This result is also the same as that according to the above embodiment. Therefore, it can be said that the MCU 40 can correctly output the position of the active pen 2 to the host processor 32 also in this modified example.

A third modification relates to passive pointer position determination processing. The MCU 40 according to this modification serves as a reference for determination (palm determination) in step S15 shown in FIG. It is configured to change the predetermined size. More specifically, the predetermined size is reduced when one or more pen positions are output by the immediately preceding pen detection step (see FIG. 3). For example, if the position of the active pen 2 is not detected by the previous position detection process of the active pen 2, the predetermined size is set to 20 mm, and the position of the active pen 2 is detected by one or more positions by the previous position detection process of the active pen 2. If it is detected, it is conceivable to set the predetermined size to 16 mm. This change processing is for making it possible to more quickly distinguish between the active pen 2 and the hand 5 when the active pen 2 is detected. In other words, it takes a certain amount of time for the hand 5 to come into contact with the touch surface 3a, and during that time there may be times when the contact area between the hand 5 and the touch surface 3a is small. In the position detection process of (1), when judging whether it is palm or finger by judging the area, it may happen that the contact position of the hand 5 is erroneously judged as the contact position of the finger 4 . According to this modification, since the predetermined size is reduced as described above, it is possible to reduce the possibility of such an erroneous determination occurring when the active pen 2 is detected.

Here, according to the position detection processing of the active pen 2 described above, the position of the active pen 2 can be detected even when the active pen 2 is not in contact with the touch surface 3a (hover state). This is because even in the hover state, the MCU 40 can detect the downlink signal DS if the active pen 2 is closer to the touch surface 3a than a certain amount. According to the third modification, the predetermined size can be reduced while the active pen 2 approaching the touch surface 3a is in the hover state, so the possibility of the erroneous determination occurring is reduced. In this state, it is possible for the active pen 2 to come into contact with the touch surface 3a.

FIG. 11 is a flow chart showing pointer position detection processing executed by the sensor controller 31 according to the fourth modification. This figure shows a modification of the flowchart shown in FIG.

The difference between FIG. 11 and FIG. 9 is that step S37 is executed after it is determined to be "palm" in step S35. More specifically, the MCU 40 according to this modification determines whether the pen position detected this time in step S35 (specifically, the candidate pen position cP[i]) exists in the vicinity of the palm area (that is, whether the candidate pen position Regarding the confirmed touch position fT[j] approximately equal to cP[i], it is determined whether the area type stored in the touch position table is "finger" or "palm"), and it is determined that it exists in the vicinity of the palm area. (i.e., when it is determined that the area type is "palm"), the pen pressure indicated by the pen pressure data included in the data Res output in the previous pen detection step (previously detected pen pressure) is valid (pen pressure > 0) or invalid (pen pressure = 0) (step S37). If it is determined to be valid, the process proceeds to step S36, and the candidate pen position cP[i] is set to the fixed pen position fP[i], and the corresponding valid flag is set to "valid" (step S36). ). On the other hand, if it is determined to be invalid, the process of step S36 is not performed. In this case, NULL is set to the corresponding fixed pen position fP[i], and "invalid" is set to the corresponding valid flag.

According to the fourth modification, when the user performs an input operation with the active pen 2, it is possible to prevent the drawing line from disappearing in the vicinity of the palm area. That is, according to the processing flow of FIG. 9, when the pen tip reaches the palm area when the user performs an input operation with the active pen, it is determined as "palm" in step S35, and the final pen position fP[i] is set. Candidate pen position cP[i] is no longer set. As a result, the coordinates are not output to the host processor 32, and the drawing line is interrupted. However, even if the pen tip approaches the palm area, as long as the user continues to perform input operations, it is preferable that the drawn line is not interrupted. According to the fourth modification, since it is determined in step S37 whether the pen pressure detected last time is valid or invalid, it is determined whether or not the user continues to perform input operations. can do. As a result, when the user continues to perform input operations, coordinate output to the host processor 32 can be continued. It is possible to prevent it from disappearing.

Next, the 1/N processing will be described in detail. In the following, the problems of the background art corresponding to the 1/N processing and the effects achieved by the introduction of the 1/N processing will be described in more detail, and then the contents of the 1/N processing will be described in detail.

FIG. 12(a) is a diagram showing a control sequence for pointer position detection processing according to the background art of the present invention, and FIG. 12(b) is a control sequence for pointer position detection processing according to the present embodiment. FIG. 4 is a diagram showing; In these figures, "T" indicates the period during which the MCU 40 performs the finger 4 position detection process, and "P" indicates the period during which the MCU 40 performs the active pen 2 position detection process.

As shown in FIG. 12(a), the MCU 40 according to the background art of the present invention continuously performs the position detection processing of the active pen 2, which takes 3 milliseconds each time, and then takes 2 milliseconds each time. It is configured to repeat the position detection processing of the finger 4 and the active pen 2 at the rhythm of performing the position detection processing of the finger 4 once. In this case, the detection rate of the finger 4 is 125 (=1/8.times.1000) times/second, and the detection rate of the active pen 2 is 250 (=2/8.times.1000) times/second. By doing so, the detection rate of the active pen 2 can be improved. However, according to this position detection process, since the detection interval of the active pen 2 is not constant, it is expected that the coordinate data of the active pen 2 sequentially output from the sensor controller 31 are transmitted at regular time intervals. A problem arises in that drawing results become unnatural in a drawing application that operates as a

On the other hand, the MCU 40 according to this embodiment, as shown in FIG. 1/N of the position detection processing (first detection processing) of the pointer) is executed. In FIG. 12(b), N=2, and in this case, the time required to execute this 1/N process is the time required for the position detection process of the finger 4 according to the example of FIG. 12(a). 1/2, or 1 millisecond. Then, the MCU 40 acquires the partial detection data indicating whether or not the finger 4 exists based on this 1/N processing, and stores it in the shift register 40a shown in FIG. step). The shift register 40a is configured to be able to store N times of partial detection data, and when writing new partial detection data into the shift register 40a, the partial detection data acquired N times before is erased.

Furthermore, each time the MCU 40 newly holds partial detection data in the memory, the MCU 40 synthesizes the N−1 pieces of partial detection data held in the memory so far with the newly held partial detection data, Overall detection data indicating whether or not the finger 4 exists on the entire touch surface 3a is generated (synthesis step). The generated overall detection data undergoes the correlation value calculation process (correlation value calculation step) described with reference to FIG. times/second) (report step).

The 1/N processing is executed at a predetermined interval (specifically, an interval of 3 milliseconds), and during this interval, the position detection processing (second detection processing) of the active pen 2 (second pointer) is performed. Everything is done only once (second detection step). Therefore, the detection rate (second detection rate) of the position of the active pen 2 is equal to the first detection rate (250 times/second). Although the detection of the active pen 2 is executed at equal intervals, this detection rate is the same value as the detection rate of the active pen 2 in the example of FIG. 12(a).

As described above, according to the pointer position detection processing according to the present embodiment, the position detection processing of the finger 4 is divided into N times and executed. It becomes possible to detect the pen 2 at regular intervals. Therefore, the problem mentioned above is eliminated. Details of the 1/N processing will be described below.

In the following description, the details of the 1/N processing will be described with first to fifth examples. The 1/N processing according to the first to fourth examples is to detect 1/N of the entire touch surface 3a (that is, detect a change in capacitance at the intersection of the sensor electrode 30X and the sensor electrode 30Y). For example, approximately 1/N of the plurality of sensor electrodes 30X (first electrodes) (see FIGS. 14 and 16 described later), or approximately 1/N of the plurality of sensor electrodes 30Y (second electrodes) (described later) (see FIGS. 15 and 17) is used. Note that approximately 1/N means that, when 1/N is not an integer, the number of sensor electrodes 30X or 30Y used each time is adjusted so as to be an integer. On the other hand, the 1/N processing according to the fifth example is the ₁ /N portion of the finger detection signal FDS (specifically, the N× _M (M =K/N) pulses) are used (see FIG. 18 to be described later). Each of these will be described in detail below. In the following, a case where N=2 and a 16×16 sensor 30 is used will be described as an example. The same is true for

First, FIG. 13 is a diagram showing an example of the finger detection signal FDS used together with the 16×16 sensor 30. As shown in FIG. As shown in the figure, the finger detection signal FDS in this case is composed of 16 pulse groups p ₁ to p ₁₆ . Each of the pulse groups p ₁ to p ₁₆ includes 16 pulses represented by "1" or "-1".

As described above, the MCU 40 and the logic unit 41 select one sensor electrode 30Y and cause the transmission unit 42 to sequentially input each pulse group p _n (n=1 to 16) to each sensor electrode 30X. It is configured to repeat for each sensor electrode 30Y. Therefore, if the time required to process one pulse group _pn is t, the time required to perform the position detection process of the finger 4 (here, the position detection process executed in step S105 shown in FIG. 2) is is t×16 (=total number of pulse groups _pn )×16 (=total number of sensor electrodes 30Y).

14A and 14B are diagrams showing a first example of the contents of the 1/N processing, FIG. 14A showing the first processing, and FIG. 14B showing the second processing. In this example, 1/N processing is performed using eight sensor electrodes 30X different from each other in each of the first and second times. More specifically, every other 16 sensor electrodes 30X aligned in the X direction are selected and used in the first process, and the remaining sensor electrodes 30X are used in the second process. .

According to this first example, the number of sensor electrodes 30X to which the finger detection signal FDS is input is _eight in _one process. It becomes possible to configure the signal FDS. Therefore, the time required to perform one process is t×8 (=total number of pulse groups _pn )×16 (=total number of sensor electrodes 30Y). It is possible to complete one process in half the time compared to the position detection process by .

Further, according to the first example, since all the sensor electrodes 30X are covered by the first and second processing, the MCU 40 holds the result of the first processing in the shift register 40a (see FIG. 5). By synthesizing the partial detection data obtained by the second processing and the partial detection data held in the shift register 40a as a result of the second processing, the overall detection data indicating whether or not the finger 4 exists on the entire touch surface 3a is generated. it becomes possible to

Furthermore, according to the first example, since there is no order between the first and second times, when new partial detection data is acquired, the MCU 40 uses the shift register It is possible to generate the whole detection data by synthesizing it with the partial detection data for N-1 times already stored in 40a. In other words, not only is the partial detection data held in the shift register 40a as a result of the first processing and the partial detection data held in the shift register 40a as a result of the second processing executed immediately after that synthesized, By synthesizing the partial detection data held in the shift register 40a as a result of the second processing and the partial detection data held in the shift register 40a as a result of the first processing executed immediately thereafter, the entire detection data can be obtained. can be generated. Therefore, it is possible to output the detection result of the finger 4 at a detection rate twice as high as the detection rate of the finger 4 in the example of FIG. 2 or FIG. 12(a).

FIGS. 15A and 15B are diagrams showing a second example of the contents of the 1/N process, where FIG. 15A shows the first process and FIG. 15B shows the second process. In this example, 1/N processing is performed using eight sensor electrodes 30Y different from each other in each of the first and second times. More specifically, every other 16 sensor electrodes 30Y aligned in the Y direction are selected and used in the first process, and the remaining sensor electrodes 30Y are used in the second process. .

According to this second example, the number of sensor electrodes 30Y to be selected in one process is eight. Therefore, the time required to perform one process is t×16 (=total number of pulse groups _pn )×8 (=total number of sensor electrodes 30Y). It is possible to complete one detection operation in half the time compared to the position detection processing by .

Also, according to the second example, all the sensor electrodes 30Y are covered by the first and second processing. By synthesizing the partial detection data obtained by the second processing and the partial detection data held in the shift register 40a as a result of the second processing, the overall detection data indicating whether or not the finger 4 exists on the entire touch surface 3a is generated. it becomes possible to

Furthermore, in the second example as well, there is no order between the first and second times. It is possible to output the detection result of the finger 4 at a detection rate that is twice as high as the detection rate.

16A and 16B are diagrams showing a third example of the contents of the 1/N process, where FIG. 16A shows the first process and FIG. 16B shows the second process. In this example, similarly to the first example, 1/N processing is performed using the eight sensor electrodes 30X different from each other in each of the first and second times. However, in this example, 8 of the 16 aligned sensor electrodes 30X are selected in order from one end and used in the first process, and the remaining sensor electrodes 30X are used in the second process. there is

According to the third example, for the same reason as the first example, one process can be completed in half the time of the position detection process according to the example of FIG. 2 or FIG. 12(a). becomes possible. Further, it is possible to generate whole detection data indicating whether or not the finger 4 exists on the entire touch surface 3a. Furthermore, it becomes possible to output the detection result of the finger 4 at a detection rate twice as high as the detection rate of the finger 4 in the example of FIG. 2 or FIG. 12(a).

FIGS. 17A and 17B are diagrams showing a fourth example of the contents of the 1/N processing, FIG. 17A showing the first processing, and FIG. 17B showing the second processing. In this example, similarly to the second example, 1/N processing is performed using the eight sensor electrodes 30Y different from each other in each of the first and second times. However, in this example, 8 of the 16 aligned sensor electrodes 30Y are selected in order from one end and used in the first process, and the remaining sensor electrodes 30Y are used in the second process. there is

According to the fourth example, for the same reason as the second example, one process can be completed in half the time of the position detection process according to the example of FIG. 2 or FIG. 12(a). becomes possible. Further, it is possible to generate whole detection data indicating whether or not the finger 4 exists on the entire touch surface 3a. Furthermore, it becomes possible to output the detection result of the finger 4 at a detection rate twice as high as the detection rate of the finger 4 in the example of FIG. 2 or FIG. 12(a).

FIGS. 18A and 18B are diagrams showing a fifth example of the contents of the 1/N processing, FIG. 18A representing the first processing, and FIG. 18B representing the second processing. In this example, only half of the 16 pulse groups p ₁ -p ₁₆ are used in the first run and the rest in the second run. More specifically, pulse groups p ₁ to p ₈ are used in the first processing, and pulse groups p ₉ to p ₁₆ are used in the second processing.

According to this fifth example, only eight pulses are input to each sensor electrode 30X in one process. Therefore, the time required to perform one process is t×8 (=total number of pulse groups _pn )×16 (=total number of sensor electrodes 30Y). It is possible to complete one detection operation in half the time compared to the position detection processing by .

Further, according to the fifth example, since all 16 pulse groups p ₁ to p ₁₆ are covered in the first and second times, the MCU 40 is set to 1 By synthesizing the partial detection data held in the shift register 40a as a result of the second processing and the partial detection data held in the shift register 40a as a result of the second processing, the finger 4 exists on the entire touch surface 3a. It is possible to generate overall detection data indicating whether or not to

Furthermore, in the fifth example as well, there is no order between the first and second times. It becomes possible to output the detection result of the finger 4 at a detection rate twice as high as the detection rate.

19 and 20 are diagrams showing examples of specific storage contents of the shift register 40a (see FIG. 5) in the fifth example. In the figure, the storage contents of the shift register 40a are displayed side by side corresponding to each sensor electrode 30Y for easy understanding. In addition, the numerical values shown in the sensor 30 in the figure indicate the capacitance value at each intersection of the sensor electrodes 30X and 30Y. Hereinafter, a method for generating overall detection data in the fifth example will be specifically described with reference to FIGS. 19 and 20. FIG.

FIG. 19 shows the contents stored in the shift register 40a immediately after the first processing is completed. In the first process, levels L ₁ to L ₈ are stored in the shift register 40a for each sensor electrode 30Y. When the first processing for a certain sensor electrode 30Y is completed, as shown in FIG. Levels L ₉ to L ₁₆ remain. Therefore, the MCU 40 synthesizes the newly stored partial detection data represented by the levels L ₁ to L ₈ and the partial detection data represented by the levels L ₉ to L ₁₆ remaining in the shift register 40a into one. The above-described correlation value is calculated using the total detection data. This enables the MCU 40 to output the coordinates indicating the position of the finger 4 to the host processor 32 when the first detection operation is completed.

FIG. 20 shows the contents stored in the shift register 40a immediately after the second processing is completed. In the second process, levels L ₉ to L ₁₆ are stored in the shift register 40a for each sensor electrode 30Y. When the second processing for a certain sensor electrode 30Y is completed, as shown in FIG. Levels L ₁ to L ₈ remain. Therefore, the MCU 40 synthesizes the newly stored partial detection data represented by the levels L ₉ to L ₁₆ and the partial detection data represented by the levels L ₁ to L ₈ remaining in the shift register 40a into one. The above-described correlation value is calculated using the total detection data. This allows the MCU 40 to output the coordinates indicating the position of the finger 4 to the host processor 32 even when the second detection operation is completed.

As described above, according to the pointer position detection processing according to the present embodiment, the position detection processing of the finger 4 is divided into N times and executed. , the detection of the active pen 2 can be performed at regular intervals. Therefore, since the detection interval of the active pen 2 is not constant, for example, a drawing application that operates on the expectation that the coordinate data of the active pen 2 sequentially output from the sensor controller 31 is transmitted at equal time intervals. , solves the problem of the background art that rendering results are unnatural. Further, according to the position detection processing according to the present embodiment, it becomes possible to detect the finger 4 at a detection rate higher than that of the background art.

Next, a position detection system 1 according to a second embodiment of the invention will be described. The position detection system 1 according to the present embodiment has a function added to the position detection system 1 according to the first embodiment to prevent unnecessary straight lines from being drawn due to the existence of the ghost positions described above. is. Hereinafter, the same reference numerals are given to the same configurations as in the first embodiment, and the description will focus on the differences from the first embodiment.

FIG. 22 is a diagram showing an example of the usage state of the position detection system 1 according to this embodiment. FIG. 23 is a diagram for explaining the operation of the host processor 32 according to the background art of this embodiment. In the following, first, the problem of this embodiment will be described with reference to FIGS. 22 and 23, and then the operation of the sensor controller 31 according to this embodiment will be described.

As shown in FIG. 22, when performing an input operation with the active pen 2, the user holds the active pen 2 with the other hand (hereinafter referred to as the left hand) opposite to the hand holding the active pen 2 (hereinafter referred to as the left hand). It may be attached to the touch surface 3a. In this case, the contact position of the left hand (the palm area Palm shown in the figure) is excluded from both the touch position and the pen position by the processing shown in the first embodiment. In some cases, the pen position (ghost position G in the figure) may be detected. This is because a current path CR (a current path from the pen electrode of the active pen 2 to the left arm through the sensor electrode 30X and back to the active pen 2 via the human body) shown in FIG. This is because the transmission signal of the active pen 2 is detected below the . Although FIG. 22 shows an example of the sensor electrode 30X, the same applies to the sensor electrode 30Y.

The level of the signal detected at the ghost position G is smaller than the level of the signal detected at the contact position of the active pen 2 (pen position P shown in the figure), and the active pen 2 that can be simultaneously detected by the tablet 3 is normally Since there is only one, as long as the active pen 2 is in contact with the touch surface 3a, this ghost position G does not pose a problem. However, if, for example, the active pen 2 suddenly moves from the bezel area 3b of the tablet 3 into the touch surface 3a along the illustrated arrow A, the sensor controller 31 may detect the actual pen position P before detecting the actual pen position P. , the ghost position G may be detected.

In FIG. 23, the first detected ghost position G in such a case is defined as the (n-1)th fixed pen position fPn _-1 , and the subsequently detected pen position P is defined as the _nth fixed pen position fPn. Each is illustrated. When the determined pen positions fP _n−1 and fP _n are successively detected in this manner, the host processor 32 receiving these supplies draws a line segment L between them as shown in FIG. . Since this line segment L is not intended by the user, it is necessary to prevent the line segment L from being drawn. This is the problem of this embodiment. The operation of the sensor controller 31 for solving this problem will be described in detail below with reference to FIG.

FIG. 24 is a flowchart showing pointer position detection processing executed by the sensor controller 31 according to the present embodiment. In this figure, steps S101 to S107 are added to the pen detection steps shown in FIG. Hereinafter, the operation of the sensor controller 31 according to the present embodiment will be described in detail while referring to FIG. 23 as well as FIG. 24 again.

After determining the pen position in step S3, the sensor controller 31 (specifically, the MCU 40 shown in FIG. 4) according to the present embodiment sets the region type to palm in the immediately preceding touch detection step (see FIG. 3). It is determined whether or not the touched position has been detected (step S101). If the sensor controller 31 determines that it is not detected, the sensor controller 31 stores the determined pen position separately from the above-described pen position table (step S107), and then performs the output process of step S4. On the other hand, if the sensor controller 31 determines that it has been detected, the sensor controller 31 next moves the pen position (previous pen position) stored in the previous step S106 within a predetermined area based on the detected palm area Palm. It is determined whether or not it is positioned (step S102).

FIG. 23 shows an example of this predetermined area. The sensor controller 31 acquires the spread of the palm area Palm from the correlation value described with reference to FIG. is configured to obtain a cross-shaped region (cross-shaped region XR) of . The predetermined area is configured by the cross area XR obtained in this way.

Returning to FIG. 24, the sensor controller 31 subsequently determines the level of the transmission signal (specifically, the position signal described above) of the active pen 2 corresponding to the pen position (current pen position) determined in step S3 this time. It is compared with a predetermined threshold, and whether or not to output the detected pen position is determined according to the result of the comparison (step S103). Specifically, when it is determined that the level of the transmission signal is lower than the predetermined threshold (low), the process proceeds after step S4, and shifts to the touch detection step shown in FIG. On the other hand, when it is determined that the level of the transmission signal is equal to or higher than the predetermined threshold (high), the process proceeds to step S104. Here, the threshold used in step S103 is set to a value greater than the predetermined value used by the MCU 40 to detect the position of the active pen 2 . The process of step S103 is nothing but the process of post-increase the threshold value for detecting the pen position, thereby reducing the possibility of the ghost position G being detected within the cross region XR. .

Next, the sensor controller 31 calculates the distance between the previous pen position and the current pen position. This distance corresponds to the distance between the fixed pen positions fP _n−1 and fP _n in FIG. Then, the sensor controller 31 determines whether this distance exceeds a predetermined value (long) or not (short) (step S104). When it is determined that the active pen 2 has left the touch surface 3a, pen-up information OUT-PROXY indicating that the active pen 2 has left the touch surface 3a and pen-down information IN- indicating that the active pen 2 has come into contact with the touch surface 3a. PROXY are sequentially output to the host processor 32 (steps S105 and S106). If it is determined in step S104 that the pen position is not exceeded, and after step S106 is completed, the sensor controller 31 stores the determined pen position separately from the pen position table described above (step S107), and then step S4. output processing.

As described above, according to the pointer position detection processing according to the present embodiment, when the distance between the pen position detected this time and the pen position detected last time exceeds a predetermined value, the pen-up information OUT -PROXY can be output to the host processor 32; Therefore, since the host processor 32 determines that the current pen position and the previous pen position belong to different strokes, the existence of the ghost position G causes an unnecessary line segment such as the line segment L shown in FIG. is prevented.

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.

For example, the pointer position detection processing according to the present embodiment can be preferably implemented in modes other than those described above. Specific examples will be described below.

FIG. 21(a) is a diagram showing a control sequence for position detection processing according to the first modification of the present embodiment. The MCU 40 according to this modification performs 1/2 processing at a predetermined interval, and synthesizes the partial detection data obtained in each processing with the partial detection data obtained in the immediately preceding processing to double the data. is configured to generate overall detection data FM1, FM2, FM3, FM4, . . . at a detection rate of . It should be noted that the position detection processing of the active pen 2 or the pixel driving operation may be executed in the interval, or the position detection processing and the pixel driving operation of the active pen 2 may be executed in a time-sharing manner.

In relation to the first modification, the MCU 40 determines whether or not the position detection processing of the finger 4 is to be executed at the predetermined interval, and executes the position detection processing of the finger 4 only when it is determined to be executed. It is good also as dividing into times and performing. If it is determined not to execute, steps S5 to S7 shown in FIG. 3 are replaced with step S103 shown in FIG. By doing so, it is possible to change the execution method of the position detection processing of the finger 4 depending on whether the position detection processing or the pixel driving operation of the active pen 2 needs to be performed or not.

FIG. 21(b) is a diagram showing a control sequence for position detection processing according to the second modification of the present embodiment. The MCU 40 according to this modification is configured to divide the position detection processing of the finger 4 into two processes even though the position detection processing of the finger 4 is continuously performed (without an interval). As a result, as shown in the figure, overall detection data FM1, FM2, FM3, FM4, . it becomes possible to

FIG. 21(c) is a diagram showing a control sequence for position detection processing according to the third modification of the present embodiment. The MCU 40 according to this modification is configured to perform the position detection processing of the finger 4 by dividing it into three processes, although the position detection processing of the finger 4 is continuously performed (without intervals). As a result, as shown in the figure, overall detection data FM1, FM2, FM3, FM4, . it becomes possible to

In addition, in the above-described embodiment, the position detection processing of the finger 4 (passive pointer) is divided into a plurality of times, but the position detection processing of the active pen 2 is also divided into a plurality of times. It may be done.

In the above embodiment, the MCU 40 always uses the pen position table and the touch position table to perform the output position determination process. If there is, that position may be determined as the pen position to be output, and the pen position determining process in step S3 may be skipped. Similarly, if only one position is detected in step S51 of FIG. 9, that position is determined as the passive pointer position to be output, and the passive pointer position determination process of step S8 is skipped. good too.

In the above embodiment, the logic unit 41 and the MCU 40 select one sensor electrode 30Y when transmitting the finger detection signal FDS, and transmit the above-described pulse groups p ₁ to p _K to the transmission unit 42. The operation of sequentially inputting to each sensor electrode 30X is repeated for each sensor electrode 30Y. good too. In this case, the second and fourth examples of the contents of the 1/N processing shown in FIGS. Since it becomes possible to share one receiving section 44 with the sensor electrodes 30Y, a new effect of reducing the circuit scale of the receiving section 44 can be obtained compared to the case where the receiving section 44 is provided for each sensor electrode 30Y. becomes possible.

1 position detection system 2 active pen 3 tablet 3a touch surface 3b bezel area 4 finger 5 hand 30 sensors 30X, 30Y sensor electrodes 31 sensor controller 32 host processor 40a shift register 40b correlator 41 logic units 42, 43 transmitter 44 receiver 45 Selection unit 50 Pattern supply unit 51 Switch 52 Code string holding unit 53 Spreading processing unit 54 Transmission guard unit 55 Amplifier circuit 56 Detection circuit 57 Analog-to-digital converters 58x, 58y Switches 59x, 59y Conductor selection circuit COM Command CR Current path DS Downlink Signal FDS Finger detection signal L ₉ to L _K level Res Data SB Start bit T ₁ to T ₄ correlation value US Uplink signal Vcom Pixel drive voltage cP[i] Candidate pen position cT[j] Candidate touch position ctrl_t1 to ctrl_t4 , ctrl_r Control signal fP[i] Determined pen position fT[j] Determined touch position G Ghost position P Pen position Palm Palm region p ₁ to p _K pulse group s ₁ to s _K signal XR Cross region

Claims (4)

performed by a sensor controller connected to the sensor pattern,
the position of a passive pointer that does not send a signal, and
A pointer position detection method for detecting the position of an active pen configured to transmit a signal from a pen electrode provided at the tip thereof, and
a pen detection step of detecting a pen signal transmitted through the pen electrode and detecting a pen position, which is the position of the active pen, based on the level of the detected pen signal;
The pen detection step includes:
When the distance between the currently detected pen position and the previously detected pen position exceeds a predetermined value, the current detection is performed after outputting pen-up information indicating that the active pen has left the touch surface. output the pen position obtained by
When the distance between the pen position detected this time and the pen position detected last time does not exceed the predetermined value, the pen position detected this time is output without outputting the pen-up information.
Pointer position detection method. In the pen detection step, when the distance between the pen position detected this time and the pen position detected last time exceeds a predetermined value, pen-down information indicating that the active pen has come into contact with the touch surface is transmitted. Output the pen position detected this time after outputting the pen-up information,
2. The pointer position detection method according to claim 1. a touch detection step of detecting a position of the passive pointer by detecting a change in capacitance in the sensor pattern and determining whether the region type of the detected position of the passive pointer is a palm or a finger; further includes
In the pen detection step, when the position of the passive pointer whose area type is determined to be palm by the touch detection step is detected, the difference between the pen position detected this time and the pen position detected last time is detected. Determining whether the distance between exceeds the predetermined value,
3. The pointer position detecting method according to claim 1 or 2. The pen detection step includes:
detecting the pen position when the level of the detected pen signal is equal to or higher than a predetermined value;
Comparing the level of the transmission signal of the active pen corresponding to the pen position detected this time with a predetermined threshold larger than the predetermined value, and outputting the pen position detected this time when the level is lower than the predetermined threshold do not
The pointer position detection method according to any one of claims 1 to 3.

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