Location input system, location indicator, and communication method

Abstract

The present invention provides a position input system, a position indicator, and a communication method that enable more efficient wireless communication using at least a master-slave scheme when multiple position detection devices are connected to a single position indicator. [Solution] The position indicator (20) comprises a wireless communication circuit (22) that performs wireless communication using a master-slave method with each position detection device (30), and a controller (21) connected to the wireless communication circuit (22) that performs communication control to the wireless communication circuit (22) so that the roles of master and slave switch according to the number of position detection devices (30) connected simultaneously.

Description

Technical Field

[0001] The present invention relates to a position input system, a position indicator, and a communication method.

Background Art

[0002] Conventionally, an input system composed of an electronic pen (or stylus) as a position indicator and an electronic device equipped with a planar pen sensor has been known. A communication method for transmitting and receiving data via a wireless communication means different from the communication used for detecting the indicated position by the electronic pen has been proposed.

[0003] Patent Document 1 discloses a pairing method for determining the transmission source of data received via wireless communication with a relatively wide communication range using information shared by communication with a relatively narrow communication range.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, Patent Document 1 only assumes a network configuration in which a plurality of position indicators are connected to one position detection device, and does not mention anything about the reverse network configuration. For example, when a plurality of position detection devices are connected to one position indicator and wireless communication using the master-slave method and / or the polling method is performed, there is room for technical improvement.

[0006] The present invention has been made in view of these problems, and its objective is to provide a position input system, a position indicator, and a communication method that can more efficiently perform wireless communication using at least a master-slave scheme when multiple position detection devices are connected to a single position indicator. [Means for solving the problem]

[0007] A position input system according to a first aspect of the present invention is a system comprising a position indicator for indicating a position and a plurality of position detection devices that receive the indication from the position indicator, wherein the position indicator comprises a wireless communication circuit that performs wireless communication using a master-slave method with each of the position detection devices, and a controller connected to the wireless communication circuit that performs communication control to the wireless communication circuit such that the roles of master and slave are switched according to the number of position detection devices connected simultaneously.

[0008] A position indicator in a second aspect of the present invention is an indicator used in conjunction with a plurality of position detection devices that receive position instructions, and comprises a wireless communication circuit that performs wireless communication using a master-slave scheme with each of the position detection devices, and a controller connected to the wireless communication circuit that performs communication control to the wireless communication circuit such that the roles of master and slave are switched according to the number of position detection devices connected simultaneously.

[0009] A third aspect of the present invention is a communication method using a position input system comprising a position indicator for indicating a position and a plurality of position detection devices that receive the indication from the position indicator, the method comprising the steps of: the position indicator performing wireless communication with each of the position detection devices using a master-slave scheme; and the position indicator or the position detection device switching between master and slave roles according to the number of position detection devices connected simultaneously. [Effects of the Invention]

[0010] According to the present invention, when multiple position detection devices are connected to a single position indicator, wireless communication using at least a master-slave scheme can be performed more efficiently. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows the configuration of the position input system in one embodiment of the present invention. [Figure 2] Figure 1 is a schematic block diagram of the electronic pen and tablet device shown. [Figure 3] This figure shows the connection status of the electronic pen and tablet device in the comparative example. [Figure 4] This is a time chart showing an example of the communication results in the comparative example in Figure 3. [Figure 5] This is a flowchart showing the first operation using the position input system shown in Figures 1 and 2. [Figure 6] This is a flowchart showing the second operation using the position input system shown in Figures 1 and 2. [Figure 7] Figures 5 and 6 show an example of the rules for assigning roles using flowcharts. [Figure 8] This diagram shows the connection status of the electronic pen and tablet terminal in the embodiment. [Figure 9] This is a time chart showing an example of the communication results in the embodiment shown in Figure 7. [Figure 10] Figure 5 shows a detailed flowchart of the first operation. [Figure 11] This diagram shows the connection status before the connection is established. [Figure 12] This diagram shows the connection status after the connection has been established. [Figure 13] This figure shows an example of how to set the polling interval. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For ease of understanding of the description, the same reference numerals are given to the same components in each drawing as much as possible, and duplicate descriptions are omitted. Also, the term "part" may be replaced with other terms such as unit, module, device, or element.

[0013] [Configuration of Position Input System 10] [System Configuration] FIG. 1 is a diagram showing the configuration of a position input system 10 according to an embodiment of the present invention. This position input system 10 is configured to be able to provide, for example, a "digital ink service" that handles handwritten content by a user U as digital data. Specifically, this position input system 10 includes one electronic pen 20 (corresponding to a "position indicator") and a plurality of tablet terminals 30 (corresponding to a "position detection device") used together with this electronic pen 20.

[0014] The electronic pen 20 is a pen-type pointing device and is configured to be communicable in one direction or two directions with the tablet terminal 30. In this embodiment, the electronic pen 20 is a stylus of an active electrostatic coupling method (AES). The electronic pen 20 and the tablet terminal 30 are capacitively coupled to each other by capacitance.

[0015] The tablet terminal 30 is a tablet-type computer with or without a display function and is a position detection device that receives an indication of a position by the electronic pen 20. In addition to the tablet terminal 30, this position detection device may be [1] a general-purpose computer such as a smartphone, a personal computer, or a wearable device, or [2] a paper-like device specialized for a pen detection function. Also, the position detection device may be [1] a device provided in a building (for example, home appliances, furniture, fixtures, etc.), or [2] a device constituting a part of a building (for example, walls, floors, windows, columns, etc.).

[0016] The electronic pen 20 and the tablet terminal 30 communicate via two-way digital wireless communication using a means separate from the communication used to detect the indicated position. Examples of digital wireless communication include Bluetooth®, BLE (Bluetooth® Low Energy), or UWB (Ultra-Wide Band). By establishing a connection between the electronic pen 20 and the tablet terminal 30, a small-scale network NT is constructed that is [1] one-to-one, [2] one-to-many, or [3] many-to-many.

[0017] In the following, to clarify the connection status with the electronic pen 20, tablet terminals 30 may be referred to separately. A tablet terminal 30 with which a small network NT has been established with the electronic pen 20 is referred to as a "connected terminal 30c". A tablet terminal 30 attempting to establish a connection with the electronic pen 20 is referred to as a "target terminal 30t". A tablet terminal 30 with which a small network NT has not been established with the electronic pen 20 is referred to as an "unconnected terminal 30n".

[0018] Figure 2 is a schematic block diagram of the electronic pen 20 and tablet terminal 30 shown in Figure 1. The electronic pen 20 consists of a pen controller 21 (corresponding to "controller"), a communication chip 22 (corresponding to "wireless communication circuit"), and a power supply module 23. The tablet terminal 30 consists of a planar sensor 31, a sensor controller 32, a host processor 33, and a communication chip 34.

[0019] The pen controller 21 is one or more circuit boards for controlling various operations of the electronic pen 20. Specifically, the pen controller 21 includes a receiving circuit 24, a transmitting circuit 25, and a microcontroller unit (MCU 26).

[0020] The receiving circuit 24 is a circuit that receives the uplink signal US via a pen electrode (not shown) and outputs it to the MCU 26. Specifically, the receiving circuit 24 is composed of an analog circuit including an amplification circuit and an AD (Analog-Digital) conversion circuit, and a digital circuit including a matched filter and a data recovery unit.

[0021] The transmitting circuit 25 is a circuit that generates a downlink signal DS and then outputs the downlink signal DS toward a pen electrode (not shown). Specifically, the transmitting circuit 25 is composed of an oscillator circuit that generates a carrier wave signal that oscillates at a predetermined frequency and a modulation circuit that modulates the carrier wave signal using data included in the control signal from the MCU 26.

[0022] The MCU26 is a control unit that includes a processor capable of controlling various operations performed by the electronic pen 20. For example, the MCU26 can perform [1] control of receiving the uplink signal US, [2] control of transmitting the downlink signal DS, or [3] control of sending and receiving data via the communication chip 22.

[0023] The communication chip 22 is an integrated circuit for performing digital wireless communication with external devices in accordance with various wireless communication standards, including Bluetooth®, BLE, or UWB. This allows the electronic pen 20 to exchange various types of data with the tablet terminal 30 via the communication chip 22.

[0024] The power module 23 is a component for supplying driving power to electronic components or electronic elements provided on the pen controller 21. The power module 23 is composed of, for example, an energy storage unit such as a battery or capacitor, and a PMIC (Power Management Integrated Circuit) that manages the power of the energy storage unit.

[0025] The planar sensor 31 of the tablet terminal 30 is a capacitive touch sensor comprising multiple sensor electrodes arranged in a planar manner. This planar sensor 31 is composed of, for example, multiple X-line electrodes for detecting the position on the X axis of the sensor coordinate system and multiple Y-line electrodes for detecting the position on the Y axis. Each line electrode may be made of a transparent conductive material containing ITO (Indium Tin Oxide) or a wire mesh sensor. In addition, the planar sensor 31 may be a self-capacitive sensor in which block-shaped electrodes are arranged in a two-dimensional grid, instead of the mutual-capacitive sensor described above.

[0026] The sensor controller 32 is connected to the surface sensor 31 and is a circuit board for controlling communication with the electronic pen 20 via the surface sensor 31. Specifically, the sensor controller 32 transmits an uplink signal US to the electronic pen 20 and receives a downlink signal DS from the electronic pen 20 to detect the indicated position of the electronic pen 20. This allows the sensor controller 32 to perform a "pen detection function" to detect the state of the electronic pen 20. If the surface sensor 31 is a capacitive touch sensor, the sensor controller 32 further performs a "touch detection function" to detect the presence and location of a touch by a passive pointer such as the user U's finger.

[0027] The host processor 33 is composed of arithmetic processing units including a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an MPU (Micro-Processing Unit). The host processor 33 can perform various functions, such as generating digital ink and controlling data transmission and reception, by reading and executing programs stored in memory (not shown).

[0028] The communication chip 34, like the communication chip 22, is an integrated circuit for performing digital wireless communication with external devices in accordance with various communication standards, including Bluetooth®, BLE, or UWB. This allows the tablet terminal 30 to exchange various types of data with the electronic pen 20 via the communication chip 34.

[0029] In the wireless communication described above, when multiple devices work together, a "master-slave scheme" is used, in which one device is assigned the role of the control side (hereinafter referred to as "master") and the remaining devices are assigned the role of the controlled side (hereinafter referred to as "slave"). The designations of master / slave are not limited to these, and may also be primary / secondary, primary / replica, parent / child, or manager / worker. For example, in the case of BLE, the master corresponds to the "center" and the slave corresponds to the "peripheral".

[0030] Furthermore, in the wireless communication described above, a "polling method" may also be used, in which multiple devices are periodically queried in sequence, and transmission / reception or processing is performed when certain conditions are met. In the case of wireless communication combined with a master-slave method, the master device transmits a polling signal to the slave device, and the slave device transmits its response signal to the master device.

[0031] [Operation of the position input system 10] The position input system 10 in this embodiment is configured as described above. Next, the operation of the position input system 10 will be explained with reference to Figures 3 to 12.

[0032] <Explanation of the comparative example> Figure 3 shows the connection status of the electronic pen 2 and tablet terminal 3 in the comparative example. Here, the letter "M" enclosed in a square frame indicates that the corresponding device has been assigned the role of "master". The letter "S" enclosed in a square frame indicates that the corresponding device has been assigned the role of "slave". The same applies to Figures 7, 11, and 12 described later.

[0033] First, the electronic pen 2 (hereinafter also referred to as "pen P") and the first tablet terminal 3 (hereinafter also referred to as "terminal A") are connected via a small network NT1. Terminal A is assigned the role of master, and pen P is assigned the role of slave. Subsequently, the electronic pen 2 and the second tablet terminal 3 (hereinafter also referred to as "terminal B") are connected via another small network NT2. Terminal B is assigned the role of master, and pen P is assigned the role of slave. From here on, we will assume that data is exchanged between pen P and the two terminals A and B using a polling method.

[0034] Figure 4 is a time chart showing an example of communication results in the comparative example of Figure 3. In the example in Figure 4, the timing for polling between terminal A and pen P is divided into 14 time zones t1 to t14. Terminal A, acting as the "master," sends polling packets Tx1 applied to the small network NT1 in odd-numbered time zones and receives response packets Tx from pen P in even-numbered time zones. Pen P, acting as the "slave," receives polling packets Tx1 in odd-numbered time zones and sends a packet in response to polling packets Tx1 (hereinafter referred to as response packets Tx) in even-numbered time zones. Through this periodic polling, pen P can periodically supply pen information it holds (e.g., pressure sensitivity or battery level) to terminal A.

[0035] In the example in Figure 4, polling is further performed between terminal B and pen P. Terminal B, acting as the "master," sends a polling packet Tx2 that applies to the small network NT2 and receives a response packet Tx from pen P. Pen P, acting as the "slave," receives polling packet Tx2 and sends a response packet Tx in response to polling packet Tx1.

[0036] For example, consider a case where the polling intervals set for each small network, NT1 and NT2, are different. During the time periods when no collision occurs between the two types of polling, pen P can selectively receive each polling packet Tx1 and Tx2. In the example in Figure 4, terminal A can obtain pen information held by pen P by receiving response packets Tx during the time periods t1, t3, t5, t11, and t13 when pen P receives polling packet Tx1 (time periods t2, t4, t6, t12, and t14).

[0037] However, during the time periods when two types of polling conflicts occur, the preceding polling becomes effective and the subsequent polling becomes ineffective. In the example in Figure 4, terminal A cannot obtain the pen information held by pen P during time periods t7 and t9 when pen P failed to receive polling packet Tx1 (time periods t8 and t10). In contrast, terminal B can obtain the pen information held by pen P by receiving response packet Tx during time periods t7 and t9 when pen P received polling packet Tx2 (time periods t8 and t10).

[0038] <Operation of Pen Controller 21> Thus, when performing wireless communication using a combination of master-slave and polling methods, the assignment of master roles to multiple devices may lead to collisions between polling systems, potentially preventing data exchange. Therefore, in this embodiment, the position input system 10 performs communication control to enable more efficient wireless communication using the master-slave method when multiple tablet terminals 30 are connected to a single electronic pen 20.

[0039] The following describes in detail the communication control by the pen controller 21 (more specifically, the MCU 26). Information processing related to communication control includes [1] connection event detection processing, [2] recognition processing between connected devices, [3] role assignment processing, [4] connection establishment / disconnection processing, or [5] polling processing.

[0040] [1] The pen controller 21 performs a "detection process" to detect events related to connection with the tablet terminal 30 (hereinafter referred to as connection events). These connection events are classified into "connection start events" to initiate a connection and "connection end events" to terminate a connection. Examples of connection events include [1] receiving an operation on a hardware switch or software switch provided on the tablet terminal 30, or [2] detecting the approach of the tablet terminal 30 via near-field communication (e.g., NFC).

[0041] [2] The pen controller 21 performs a "recognition process" to recognize the tablet terminal 30, which is identified through the detection of a connection event. In the case of BLE, this recognition process is performed through advertising and scanning as defined by the GAP (Generic Access Profile). "Advertising" is a function in which peripheral devices (corresponding to "slave devices") send packets on the advertising channel to inform others of their own information. "Scanning" is a function in which the central device (corresponding to "master devices") enters a receiving state and acquires information about peripheral devices in the vicinity.

[0042] [3] The pen controller 21 performs an "assignment process" to assign a communication role (hereinafter also simply referred to as "role") to the electronic pen 20 or the tablet terminal 30. For example, the pen controller 21 assigns either a master or slave role depending on the number of tablet terminals 30 connected simultaneously.

[0043] When only one device is connected, the pen controller 21 establishes a one-to-one network consisting of, for example, an electronic pen 20 assigned the role of slave and a tablet terminal 30 assigned the role of master. Alternatively, the pen controller 21 may establish a one-to-one network consisting of an electronic pen 20 assigned the role of master and a tablet terminal 30 assigned the role of slave.

[0044] When there are two or more connected devices, the pen controller 21 establishes a one-to-many network consisting of an electronic pen 20 assigned the role of master and a group of tablet terminals 30 each assigned the role of slave. Here, a role switch occurs if [1] the electronic pen 20 is assigned the role of slave when the number of connected devices increases from one to two, or [2] the electronic pen 20 is assigned the role of master when the number of connected devices decreases from two to one.

[0045] Let's assume a situation where a one-to-one network is established between one of the multiple tablet terminals 30 (hereinafter also referred to as the "first detection device") and the electronic pen 20. In this case, when a connection is established between another of the multiple tablet terminals 30 (hereinafter also referred to as the "second detection device") and the electronic pen 20, the pen controller 21 establishes a one-to-many network consisting of the electronic pen 20, the first detection device, and the second detection device. Here, the method of establishing the one-to-many network differs depending on the role of the electronic pen 20 in the one-to-one network.

[0046] Firstly, if the first detection device is assigned the role of master and the electronic pen 20 is assigned the role of slave, the pen controller 21 terminates the connection between the first detection device and the electronic pen 20, and then constructs a one-to-many network consisting of the electronic pen 20, which is assigned the role of master, and the first and second detection devices, which are respectively assigned the roles of slave.

[0047] Secondly, if the electronic pen 20 is assigned the role of master and the first detection device is assigned the role of slave, the pen controller 21 adds the second detection device, which is assigned the role of slave, to the one-to-one network and constructs a new one-to-many network.

[0048] Assume a one-to-many network is established, consisting of an electronic pen 20 assigned the role of master, and a first detection device and a second detection device, which are two tablet terminals 30 each assigned the role of slave. In this case, when the connection between the second detection device and the electronic pen 20 is disconnected, the pen controller 21 further terminates the connection between the first detection device and the electronic pen 20, and then establishes a one-to-one network consisting of the electronic pen 20 assigned the role of slave and the first detection device assigned the role of master.

[0049] [4] The pen controller 21 performs a "connection process" to establish a connection with one or more tablet terminals 30, or a "disconnection process" to disconnect a connection with one or more tablet terminals 30, in accordance with predetermined communication rules.

[0050] [5] The pen controller 21 performs a "polling process" to exchange data with the tablet terminal 30 using a polling method. When the electronic pen 20 is the "master", it transmits at least one type of polling signal to the tablet terminal 30, which is the "slave", at predetermined polling intervals and in a time-division manner. When the electronic pen 20 is the "slave", it transmits a response signal to the received polling signal to the tablet terminal 30, which is the "master".

[0051] The polling interval may be a fixed value or a variable value. In a one-to-many network, the polling interval may be the same value for all tablet terminals 30 assigned the role of slaves, or it may be different for each tablet terminal 30. For example, the polling interval for a tablet terminal 30 in use may be set to be shorter than the polling interval for a tablet terminal 30 that is not in use.

[0052] The state of the tablet terminal 30 may be classified, for example, into "used state" and "unused state". The used state includes "in use", which is the state in which it is currently being used, or "available", which is the state in which it is likely to be used soon. The unused state includes "not in use", which is the state in which it is unlikely to be used soon. The above states are classified according to, for example, [1] the presence or absence of pressure acting on the electronic pen 20 (on / off state), [2] the reception strength of the downlink signal DS, [3] the operating mode of the tablet terminal 30, or [4] a combination of the above state quantities.

[0053] For example, if the pen pressure of the electronic pen 20 is "on," the pen controller 21 may determine that the tablet device with the highest reception strength among the two or more tablet devices 30 belonging to the group is "in use." Also, if the pen pressure of the electronic pen 20 is "off," the pen controller 21 may determine that the tablet device with a reception strength exceeding a threshold is "available," and the tablet device with a reception strength below the threshold is "not in use." Furthermore, the pen controller 21 may determine that the tablet device is "not in use" among the two or more tablet devices 30 belonging to the group that is in an operating mode that is running during standby or degraded operation (e.g., sleep mode, standby mode, power saving mode, etc.).

[0054] The polling signal or response signal may contain various information held or generated by the transmitting device. For example, the electronic pen 20, acting as the "master," sends a polling signal containing its own pen information to the tablet terminal 30, acting as the "slave." The electronic pen 20, acting as the "slave," also sends a response signal containing its own pen information to the tablet terminal 30, acting as the "master." Examples of pen information include the identification information of the electronic pen 20, whether or not pressure is applied, the magnitude of the pressure applied, or the battery level.

[0055] <Explanation of Role Switching Operation> Figure 5 is a flowchart showing the first operation by the position input system 10 as shown in Figures 1 and 2. This "first operation" relates to the communication control of the electronic pen 20 when initiating wireless communication with the target terminal 30t.

[0056] In step SP10, the electronic pen 20 (more specifically, the pen controller 21) detects an event to initiate a connection with the tablet terminal 30 (i.e., a connection start event). Through this detection, the target terminal 30t is identified.

[0057] In step SP12, the pen controller 21 checks the connection status of the electronic pen 20, triggered by the detection in step SP10. If there are no connected terminals 30c at this time (step SP12: none), the pen controller 21 proceeds to step SP14.

[0058] In step SP14, the pen controller 21 establishes a connection with the target terminal 30t and proceeds to the next step SP16. Here, the target terminal 30t is assigned the role of "master" and the electronic pen 20 is assigned the role of "slave". Through this establishment, the target terminal 30t transitions to the connected terminal 30c.

[0059] In step SP16, the pen controller 21 initiates wireless communication using a polling method with one connected terminal 30c.

[0060] Returning to step SP12, if n (n≧1) or more connected terminals 30c are connected simultaneously and the electronic pen 20 is assigned the role of "master" (step SP12: master[1:n]), the pen controller 21 proceeds to step SP18.

[0061] In step SP18, the pen controller 21 establishes a connection with the target terminal 30t, and then proceeds to step SP16. Here, the electronic pen 20 is assigned the role of "master," and the target terminal 30t is assigned the role of "slave." Through this establishment, the target terminal 30t transitions to the connected terminal 30c.

[0062] In step SP16, the pen controller 21 initiates wireless communication using a polling method with (n+1) connected terminals 30c.

[0063] Returning to step SP12, if it is connected to one connected terminal 30c and the electronic pen 20 is assigned the role of "slave" (step SP12:slave[1:1]), the pen controller 21 proceeds to step SP20.

[0064] In step SP20, the pen controller 21 disconnects all currently established connections. Through this disconnection, the connected terminal 30c transitions to the target terminal 30t.

[0065] In step SP22, the pen controller 21 changes its role from "slave" to "master".

[0066] In step SP24, the pen controller 21 re-establishes a connection with the two target terminals 30t, and then proceeds to step SP16. Here, the electronic pen 20 is assigned the role of "master," and the two target terminals 30t are assigned the role of "slave." Through this establishment, the target terminals 30t transition to connected terminals 30c.

[0067] In step SP16, the pen controller 21 initiates wireless communication using a polling method with the two connected terminals 30c. In this way, the electronic pen 20 communicates wirelessly with the corresponding tablet terminal 30.

[0068] Figure 6 is a flowchart showing the second operation by the position input system 10 as shown in Figures 1 and 2. This "second operation" relates to the communication control of the electronic pen 20 when terminating wireless communication with the connected terminal 30c.

[0069] In step SP30, the electronic pen 20 (more specifically, the pen controller 21) detects an event to terminate the connection with the tablet terminal 30 (i.e., a connection termination event). Through this detection, the target terminal 30t is identified.

[0070] In step SP32, the pen controller 21 checks the current number of connected devices (n) based on the detection in step SP30. If there is only one connected terminal 30c (step SP12: n=1), the pen controller 21 proceeds to step SP34.

[0071] In step SP34, the pen controller 21 disconnects the connection with the target terminal 30t and terminates wireless communication with the tablet terminal 30. As a result, the electronic pen 20 terminates the execution of the flowchart in Figure 6.

[0072] Returning to step SP32, if there are three or more connected terminals 30c (step SP12: n≧3), the pen controller 21 proceeds to step SP36.

[0073] In step SP34, the pen controller 21 disconnects the connection with the target terminal 30t. Through this disconnection, the target terminal 30t transitions to an unconnected terminal 30n.

[0074] In step SP36, the pen controller 21 continues to communicate wirelessly with the remaining (n-1) connected terminals 30c using a polling method.

[0075] Returning to step SP32, if there are two connected terminals 30c (step SP32: n=2), the pen controller 21 proceeds to step SP38.

[0076] In step SP38, the pen controller 21 disconnects all currently established connections. Through this disconnection, the target terminal 30t transitions to an unconnected terminal 30n, and the connected terminal 30c transitions to a target terminal 30t.

[0077] In step SP40, the pen controller 21 changes its role from "master" to "slave".

[0078] In step SP42, the pen controller 21 re-establishes a connection with one target terminal 30t and proceeds to step SP38. Here, one target terminal 30t is assigned the role of "master" and the electronic pen 20 is assigned the role of "slave". Through this establishment, the target terminal 30t transitions to the connected terminal 30c.

[0079] In step SP36, the pen controller 21 continues wireless communication with the remaining connected terminal 30c using a polling method.

[0080] Figure 7 shows an example of the rules for assigning roles using the flowcharts in Figures 5 and 6. More specifically, Figure 7 is a table showing the relationship between the number of devices connected to the electronic pen 20 and the roles assigned to each device. When there is one connected device, the tablet terminal 30 is assigned the role of "master," and the electronic pen 20 is assigned the role of "slave." When there are two or more connected devices, the electronic pen 20 is assigned the role of "master," and each tablet terminal 30 is assigned the role of "slave."

[0081] <Effects of role switching operation> Next, we will explain the effects of the role switching operation described in Figures 5 to 7, referring to Figures 8 and 9.

[0082] When only one device is connected, the electronic pen 20 responds to a polling signal from the tablet device 30 by transmitting a response signal containing pen information. By employing on-demand transmission, unnecessary transmission opportunities for the electronic pen 20 can be reduced, thereby lowering the power consumption of the electronic pen 20.

[0083] When two or more devices are connected, the electronic pen 20 transmits polling signals containing pen information to two or more tablet terminals 30 using time-division multiplexing. By employing time-division multiplexing primarily from the electronic pen 20, collisions between polling signals can be prevented, thereby reducing the loss of opportunities to supply pen information from the electronic pen 20.

[0084] Figure 8 shows the connection status of the electronic pen 20 and the tablet terminal 30 in the embodiment. First, as in the case of Figure 3, the electronic pen 20 (hereinafter also referred to as "pen P") and the first tablet terminal 30 (hereinafter also referred to as "terminal A") are connected. Terminal A is assigned the role of master, and pen P is assigned the role of slave. Subsequently, with the connection of pen P to the second tablet terminal 30 (hereinafter also referred to as "terminal B"), pen P, terminals A and B are connected via a single small network NT. Pen P is assigned the role of master, and terminals A and B are assigned the roles of slave. Hereafter, we will assume that data is exchanged between pen P and the two terminals A and B using a polling method.

[0085] Figure 9 is a time chart showing an example of the communication results in the embodiment of Figure 8. In the example of Figure 9, as in Figure 4, the timing for polling with terminal A and pen P is divided into 14 time zones t1 to t14. Pen P, acting as the "master," alternately sends polling packets Tx1 and Tx2, which are applied to the small network NT, during odd-numbered time zones, and alternately receives response packets Tx from terminals A and B during even-numbered time zones. Terminals A and B, acting as "slaves," alternately receive polling packets Tx1 and Tx2 during odd-numbered time zones, and alternately send packets responding to polling packets Tx1 and Tx2 (i.e., response packets TxA and TxB) during even-numbered time zones. Through this periodic polling, pen P can periodically supply the pen information it holds to terminals A and B.

[0086] In the example shown in Figure 9, pen P performs time-division multiplexing of polling to prevent collisions between the two types of polling. As a result, terminal A can obtain pen information held by pen P through the reception of polling packet Tx1 (time zones t1, t5, t9, t13). Terminal B can also obtain pen information held by pen P through the reception of polling packet Tx1 (time zones t3, t7, t11).

[0087] Alternatively, terminals A and B can periodically supply terminal information they possess (e.g., operating mode type, pen detection result, etc.) to pen P. Specifically, pen P can obtain terminal information held by terminal A through the reception of response packet TxA (time zones t2, t6, t10, t14). Also, pen P can obtain terminal information held by terminal B through the reception of response packet TxB (time zones t4, t8, t12).

[0088] [Specific examples of role switching operations] Next, we will explain specific examples of role switching operations, referring to Figures 10 to 13.

[0089] Figure 10 is a detailed flowchart of the first operation shown in Figure 5. Here, we assume that BLE is used as the wireless communication standard.

[0090] In step SP50, the electronic pen 20 detects a connection start event when the unconnected terminal 30n receives a request operation from user U.

[0091] In step SP52, the electronic pen 20 and the unconnected terminal 30n recognize each other as connected devices by performing either advertising by the peripheral (corresponding to "slave") or scanning by the central (corresponding to "master"), triggered by detection in step SP50. As a result, the unconnected terminal 30n transitions to the target terminal 30t.

[0092] In step SP54, the electronic pen 20 establishes a connection with the tablet terminal 30 (i.e., the target terminal 30t) recognized in step SP52, and then proceeds to the next step SP56. Here, the electronic pen 20 is assigned the role of "peripheral," and the target terminal 30t is assigned the role of "central." Through this establishment, the target terminal 30t transitions to connected terminal 30c.

[0093] In step SP56, the electronic pen 20 checks whether a standalone one-to-one network has been established after the execution of step SP54. If a standalone one-to-one network is established (step SP56: YES), the electronic pen 20 proceeds to the next step SP58.

[0094] In step SP58, the electronic pen 20 starts wireless communication using the polling method with one connected terminal 30c that was established in step SP54.

[0095] On the other hand, returning to step SP56, if it is not a standalone one-to-one network (step SP56: NO), the electronic pen 20 proceeds to step SP60.

[0096] In step SP60, the electronic pen 20 terminates by disconnecting all currently established connections. Through this disconnection, one connected terminal 30c temporarily switches to the target terminal 30t.

[0097] In step SP62, the electronic pen 20 changes its role from "peripheral" to "central". As a result, the electronic pen 20 is assigned the role of "central", while the two tablet terminals 30 (target terminals 30t) are each assigned the role of "peripheral".

[0098] In step SP64, the electronic pen 20 re-establishes a connection with the two target terminals 30t, and then proceeds to step SP16. Here, the electronic pen 20 is assigned the role of "central," and the two target terminals 30t are assigned the role of "peripheral." Through this re-establishment, the target terminals 30t transition to connected terminals 30c.

[0099] Figure 11 shows the connection status before a connection is established. In the example in Figure 11, three tablet terminals 30 are arranged side by side. The tablet terminals 30 on the left and in the center (i.e., connected terminals 30c) are connected to the electronic pen 20 via a small network NT. Here, the electronic pen 20 is assigned the role of "central" (master), and the connected terminals 30c are assigned the role of "peripheral" (slave). The tablet terminal 30 on the right corresponds to the device attempting to establish a connection with the electronic pen 20 (i.e., the target terminal 30t).

[0100] Figure 12 shows the connection status after the connection has been established. More specifically, Figure 12 shows the target terminal 30t in Figure 11 connected to the electronic pen 20. All three tablet terminals 30 (i.e., connected terminals 30c) are connected to the electronic pen 20 via a single small network NT. Here, the electronic pen 20 is assigned the role of "central" (master), and the connected terminals 30c are assigned the role of "peripheral" (slave).

[0101] Figure 13 shows an example of how to set the polling interval. More specifically, Figure 13 is a table showing the relationship between the usage status of the tablet device 30 and the polling interval. When the tablet device 30 is "in use," the polling interval is set to a relatively short time. When the tablet device 30 is "available," the polling interval is set to a medium time. When the tablet device 30 is "not in use," the polling interval is set to a relatively long time.

[0102] [Summary of Embodiments] As described above, the position input system 10 in this embodiment is configured to include a position indicator (here, an electronic pen 20) for indicating a position, and a plurality of position detection devices (here, tablet terminals 30) that receive instructions from the electronic pen 20. The electronic pen 20 includes a wireless communication circuit (here, a communication chip 22) that performs wireless communication with each tablet terminal 30 using a master-slave method, and a controller (here, a pen controller 21) connected to the communication chip 22 that controls communication with the communication chip 22 so that the roles of master and slave switch according to the number of tablet terminals 30 connected simultaneously.

[0103] Furthermore, the communication method using the position input system 10 in this embodiment includes the steps of: the electronic pen 20 performing wireless communication with each tablet terminal 30 using a master-slave scheme (SP16, SP38, SP58); and the electronic pen 20 or the tablet terminal 30 switching between master and slave roles according to the number of tablet terminals 30 connected simultaneously (SP22, SP42, SP62).

[0104] With this configuration, when multiple tablet devices 30 are connected to a single electronic pen 20, wireless communication using at least a master-slave scheme can be performed more efficiently through dynamic switching of roles according to the number of connected devices.

[0105] Furthermore, wireless communication may use a master-slave scheme combined with a polling scheme. This makes it easier to deal with collisions between polling systems.

[0106] Furthermore, if only one device is connected, the pen controller 21 may perform communication control to establish a one-to-one network consisting of the electronic pen 20, which is assigned the role of slave, and the tablet terminal 30, which is assigned the role of master. By employing on-demand transmission, unnecessary transmission opportunities for the electronic pen 20 can be reduced, thereby suppressing the power consumption of the electronic pen 20.

[0107] Furthermore, if there are two or more connected devices, the pen controller 21 may perform communication control to construct a one-to-many network consisting of a group of electronic pens 20 assigned the role of master and a group of tablet terminals 30 each assigned the role of slave. By employing time-division transmission mainly using the electronic pen 20, collisions between polling can be prevented, thereby reducing the loss of opportunities to supply pen information from the electronic pen 20.

[0108] Furthermore, when a one-to-one network consisting of the first detection device (one of the multiple tablet terminals 30) and the electronic pen 20 is established, the pen controller 21 may perform communication control to establish a one-to-many network consisting of the electronic pen 20, the first detection device, and the second detection device when a connection is established between the second detection device (another of the multiple tablet terminals 30) and the electronic pen 20. This makes it possible to build the small-scale network NT more smoothly when the number of connected devices transitions from one to two.

[0109] Furthermore, if the first detection device is assigned the role of master and the electronic pen 20 is assigned the role of slave, the pen controller 21 may, after terminating the connection between the first detection device and the electronic pen 20, perform communication control to construct a one-to-many network consisting of the electronic pen 20, which is assigned the role of master, and the first and second detection devices, which are respectively assigned the roles of slave. This makes it possible to construct a small-scale network NT more smoothly when the number of connected devices transitions from one to two, when the electronic pen 20 is assigned the role of slave.

[0110] Furthermore, if the electronic pen 20 is assigned the role of master and the first detection device is assigned the role of slave, the pen controller 21 may perform communication control to add the second detection device, which is assigned the role of slave, to the one-to-one network and construct a new one-to-many network. This makes it possible to construct a small-scale network NT more smoothly when the number of connected devices changes from one to two, when the electronic pen 20 is assigned the role of master.

[0111] Furthermore, when a one-to-many network is established consisting of an electronic pen 20 assigned the role of master and a first detection device and a second detection device, each assigned the role of slave, the pen controller 21 may terminate the connection between the second detection device and the electronic pen 20, and then, after terminating the connection between the first detection device and the electronic pen 20, perform communication control to establish a one-to-one network consisting of the electronic pen 20 assigned the role of slave and the first detection device assigned the role of master. This makes it possible to more smoothly establish the small-scale network NT when the number of connected devices changes from two to one, especially when the electronic pen 20 is assigned the role of master.

[0112] Furthermore, the pen controller 21 may classify the state of the tablet terminals 30 belonging to the group constituting the one-to-many network into an active state and an inactive state, and perform communication control so that the polling interval for the active tablet terminals 30 is shorter than the polling interval for the inactive tablet terminals 30. This allows for polling at a higher frequency for tablet terminals 30 that are more likely to be used.

[0113] Furthermore, the position indicator is an electronic pen 20 capable of measuring the pressure applied to the pen tip. If the electronic pen 20 is assigned the role of master, it may transmit a polling signal containing pressure information to each tablet terminal 30. This allows each tablet terminal 30 to acquire the pressure information of the electronic pen 20 in a timely manner.

[0114] [Differentiation] It should be noted that the present invention is not limited to the embodiments described above, and can be freely modified without departing from the spirit of the invention. Alternatively, the various components may be combined in any way that does not create a technical inconsistency. Alternatively, the execution order or whether or not the steps constituting the flowchart are executed may be changed, as long as no technical inconsistency arises.

[0115] In the embodiment described above, the case in which the electronic pen 20 primarily controls communication was used as an example, but the primary control entity for wireless communication is not limited to this. Specifically, the tablet terminal 30 may primarily control communication, or the electronic pen 20 and the tablet terminal 30 may cooperate in controlling communication. For example, when the tablet terminal 30 is the primary control entity, the host processor 33 (Figure 2) performs the function of a "controller," and the wireless chip 34 (Figure 2) performs the function of a "wireless communication circuit."

[0116] In the embodiment described above, a pen-type electronic pen 20 was used as an example, but the form of the position indicator is not limited to this pen type. Also, although the example was given using the case where the electronic pen 20 is an active electrostatic coupling (AES) stylus, the electronic pen 20 may instead be an electromagnetic induction (EMR) stylus. In this device configuration, the tablet terminal 30 is provided with a planar sensor (or digitizer) having multiple loop coils formed thereon, and the electronic pen 20 is provided with a receiving circuit that receives the magnetic field signal emitted by the planar sensor. [Explanation of symbols]

[0117] 10…Position input system, 20…Electronic pen (position indicator), 21…Pen controller (controller), 22…Communication chip (wireless communication circuit), 23…Power module, 24…Receiver circuit, 25…Transmitter circuit, 26…MCU, 30…Tablet terminal (position detection device), 30c…Connected terminal, 30n…Unconnected terminal, 30t…Target terminal, 31…Surface sensor, 32…Sensor controller, 33…Host processor, 34…Communication chip

Claims

1. A position input system comprising a position indicator for indicating a position, and a plurality of position detection devices that receive the indication from the position indicator, The position indicator is, A wireless communication circuit that performs wireless communication using a master-slave scheme with each of the aforementioned position detection devices, A controller connected to the wireless communication circuit, which performs communication control to the wireless communication circuit such that the roles of master and slave switch according to the number of position detection devices connected simultaneously, A position input system equipped with the following features.

2. The aforementioned wireless communication is a communication method that combines the master-slave scheme with a polling scheme. The position input system according to claim 1.

3. The aforementioned controller, When the number of connected devices is one, the communication control is performed to construct a one-to-one network consisting of the position indicator assigned the role of slave and the position detection device assigned the role of master. If the number of connected devices is two or more, the communication control is performed to construct a one-to-many network consisting of a position indicator assigned the role of master and a group of position detection devices, each assigned the role of slave. The position input system according to claim 2.

4. The aforementioned controller, In a state in which the one-to-one network consisting of a first detection device, which is one of the multiple position detection devices, and the position indicator is established, When a connection is established between the second detection device, which is another of the multiple location detection devices, and the location indicator, the communication control is performed to construct the one-to-many network consisting of the location indicator, the first detection device, and the second detection device. The position input system according to claim 3.

5. The aforementioned controller, If the first detection device is assigned the role of master and the position indicator is assigned the role of slave, After terminating the connection between the first detection device and the position indicator, the communication control is performed to construct the one-to-many network consisting of the position indicator, which is assigned the role of master, and the first detection device and the second detection device, which are each assigned the roles of slave. The position input system according to claim 4.

6. The aforementioned controller, If the position indicator is assigned the role of master and the first detection device is assigned the role of slave, the communication control is performed to add the second detection device, which is assigned the role of slave, to the one-to-one network and to newly construct the one-to-many network. The position input system according to claim 4.

7. The aforementioned controller, In a state in which the one-to-many network is constructed, consisting of the position indicator assigned the role of master, and the first detection device and the second detection device, each assigned the role of slave, When terminating the connection between the second detection device and the position indicator, after further terminating the connection between the first detection device and the position indicator, the communication control is performed to construct the one-to-one network consisting of the position indicator assigned the role of slave and the first detection device assigned the role of master. The position input system according to claim 4.

8. The aforementioned controller, The state of the position detection devices belonging to the group constituting the one-to-many network is classified into an in-use state and an in-use state. The communication control is performed such that the polling interval for the position detection device in use is shorter than the polling interval for the position detection device in non-use. The position input system according to claim 3.

9. The position indicator is an electronic pen capable of measuring the pressure applied to the pen tip. If the electronic pen is assigned the role of master, it transmits a polling signal containing pressure information relating to the pen pressure to each of the position detection devices. The position input system according to claim 3.

10. A position indicator used in conjunction with multiple position detection devices that receive position instructions, A wireless communication circuit that performs wireless communication using a master-slave scheme with each of the aforementioned position detection devices, A controller connected to the wireless communication circuit, which performs communication control to the wireless communication circuit such that the roles of master and slave switch according to the number of position detection devices connected simultaneously, A position indicator equipped with a position indicator.

11. A communication method using a position input system comprising a position indicator for indicating a position and a plurality of position detection devices that receive the indication from the position indicator, The position indicator performs wireless communication with each of the position detection devices using a master-slave method, The position indicator or position detection device switches between master and slave roles depending on the number of position detection devices connected simultaneously. A communication method that includes the following features.

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