Sensor controller and stylus

Abstract

The invention provides a sensor controller and a stylus, which can reduce the load of the sensor controller and reduce the influence of the stylus on the noise in the reception of an uplink signal. The sensor controller (31) is configured so as to be able to transmit an uplink signal (US) having a predetermined preamble by means of either a first setting or a second setting that are different from each other, to select either the first setting or the second setting, and to transmit the uplink signal (US) by means of the selected setting.

Description

Technical Field

[0001] The invention relates to a sensor controller and a touch pen. Background Art

[0002] Among the position detection devices using the active electrostatic method, there are position detection devices that are configured to enable bidirectional communication between a sensor controller and a stylus pen via a sensor electrode group embedded in a touch surface. Hereinafter, the signal sent from the sensor controller to the stylus pen in this bidirectional communication is referred to as an "uplink signal", and the signal sent from the stylus pen to the sensor controller is referred to as a "downlink signal".

[0003] A specific method for generating an uplink signal is disclosed in Patent Document 1. As described in Patent Document 1, the uplink signal is generated by spreading a symbol string obtained by adding a predetermined preamble to the beginning of a command to be transmitted using a predetermined spreading code (a spreading code having an autocorrelation characteristic).

[0004] Patent Document 2 discloses an example of a stylus pen configured to avoid the influence of an interference signal when a sensor controller receives a downlink signal by adjusting the frequency of a downlink signal when a received uplink signal includes an interference signal.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-042867

[0008] Patent Document 2: Chinese Patent Publication No. 112286381 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In recent years, there have been foldable smartphones and tablet terminals that use sensor electrode groups made of ITO (indium tin oxide) films with greater resistance than metal films, which are position detection devices that impose a large load on the sensor controller. In addition, if noise is superimposed on the uplink signal, it may be difficult for the stylus to receive the uplink signal.

[0011] Therefore, one object of the present invention is to provide a sensor controller and a stylus pen that can reduce the load on the sensor controller and reduce the influence of noise in the stylus pen on the reception of uplink signals.

[0012] In addition, when the sensor controller is configured to send an uplink signal using one of two or more different methods, the stylus pen that is only waiting for the uplink signal sent using the other method will fail to receive the uplink signal. In this case, the sensor controller cannot start communication with the stylus pen, so improvement is needed.

[0013] Therefore, another object of the present invention is to provide a sensor controller that can appropriately start communication with a stylus pen while transmitting an uplink signal using any one of two or more different methods.

[0014] Means for solving problems

[0015] The sensor controller of the first aspect of the present invention is configured to be able to send an uplink signal with a specified preamble code through either a first setting or a second setting that are different from each other, select either the first setting or the second setting, and send the uplink signal through the setting of the selected one.

[0016] A stylus pen according to a first aspect of the present invention includes a receiving unit configured to be capable of detecting both an uplink signal transmitted in a first setting and an uplink signal transmitted in a second setting different from the first setting.

[0017] The sensor controller on the second side of the present invention sends a first uplink signal through a first method, determines whether the stylus pen fails in detecting the first uplink signal, and when it is determined through the determination that the stylus pen fails in detecting the first uplink signal, sends a second uplink signal through a second method different from the first method.

[0018] Effects of the Invention

[0019] According to the first aspect of the present invention, the sensor controller can send the uplink signal using the first setting and the second setting separately, thereby reducing the load on the sensor controller and also reducing the influence of noise in the stylus pen on the reception of the uplink signal.

[0020] According to the second aspect of the present invention, the sensor controller sends a second uplink signal when the stylus fails to detect the first uplink signal, thereby being able to appropriately start communication with the stylus while using any one of two or more different methods to send the uplink signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a diagram showing the configuration of a position detection system 1 according to an embodiment of the present invention.

[0022] Figure 2 It is a diagram showing the transmission and reception timing of the uplink signal US and the downlink signal DS.

[0023] Figure 3 (a) is a diagram showing the structure of an uplink signal US, and (b) is a diagram showing an example of a spreading code having an autocorrelation characteristic.

[0024] Figure 4 2 is a diagram showing the internal structure of the stylus pen 2 .

[0025] Figure 5 It is a diagram showing the transition of the operation mode of the MCU 14 .

[0026] Figure 6 : is a flowchart showing the processing performed by the sensor controller 31 .

[0027] Description of symbols

[0028] 1 Position detection system

[0029] 2 Stylus

[0030] 3 Position detection device

[0031] 3a Panel surface

[0032] 10 Pen tip electrode

[0033] 10a Pen tip

[0034] 10b Pen ring

[0035] 11 Wireless Communications Department

[0036] 12. Pressure sensor

[0037] 13 Ministry of Communications

[0038] 14 MCU

[0039] 20 AD converter

[0040] 21 Custom Logic Circuits

[0041] 21a Correlator

[0042] 22, 23 Clock Generator

[0043] 24 Switching Circuit

[0044] 30 Sensors

[0045] 31 Sensor Controller

[0046] 32 Main processor

[0047] 33 Wireless Communications Department

[0048] DS Downlink Signal

[0049] F Frame

[0050] PRE Preamble

[0051] US uplink signal DETAILED DESCRIPTION

[0052] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0053] Figure 1 1 is a diagram showing a configuration of a position detection system 1 according to the present embodiment. As shown in the diagram, the position detection system 1 is configured to include a stylus pen 2 and a position detection device 3 .

[0054] First, let's focus on the position detection device 3. The position detection device 3 is a computer that has the function of detecting the stylus 2. Figure 1 As shown in FIG. 1 , the position detection device 3 is configured to include a panel surface 3a (touch surface), a sensor 30 disposed immediately below the panel surface 3a, a sensor controller 31, a main processor 32, and a wireless communication unit 33. In a typical example, the position detection device 3 is a personal computer such as a smartphone, a tablet terminal, or a notebook computer. The panel surface 3a may also serve as a display surface of a display, in which case the display is disposed overlapping the sensor 30.

[0055] The sensor 30 is a device used for communication between the sensor controller 31 and the stylus pen 2, and is configured to have a sensor electrode group arranged in the panel surface 3a. Specifically, the sensor electrode group is configured to include a plurality of X electrodes extending in the y direction in the panel surface 3a and arranged side by side at equal intervals in the x direction, and a plurality of Y electrodes extending in the x direction in the panel surface 3a and arranged side by side at equal intervals in the y direction. The plurality of X electrodes and the plurality of Y electrodes are independently connected to the sensor controller 31. One of the plurality of X electrodes and the plurality of Y electrodes can be used as a common electrode in the display, and the position detection device 3 in this case is called an "In-cell type". On the other hand, the plurality of X electrodes and the plurality of Y electrodes may not be used as a common electrode in the display, and the position detection device 3 in this case is called an "On-cell type" or an "Out-cell type".

[0056] When the sensor 30 is arranged on the upper surface of the display, in order to ensure the visual confirmation of the display, the plurality of X electrodes and the plurality of Y electrodes are composed of a transparent conductor such as the above-mentioned ITO or a thin wire such as a mesh conductor. The X electrodes and Y electrodes thus composed have a larger resistance than those composed of a plate-like metal film, and a large load is applied to the sensor controller 31. In addition, in the case where the position detection device 3 is a foldable smartphone that has appeared in recent years, a large load is also applied to the sensor controller 31. One of the purposes of the invention of the present application is to enable the sensor controller 31 to be subjected to such a large load to send an uplink signal by using a lower speed operation, thereby reducing its load.

[0057] The sensor controller 31 is an integrated circuit having a function of deriving the position of the stylus pen 2 in the panel surface 3a (hereinafter referred to as "pen position") and acquiring data (hereinafter referred to as "pen data") from the stylus pen 2 by communicating with the stylus pen 2 via the sensor 30 (first communication method), and a function of sequentially supplying reports including the derived pen position and acquired pen data to the main processor 32. The sensor controller 31 is configured to realize these functions and execute various processes described below by executing a program installed as hardware or a program stored in a built-in memory.

[0058] The communication between the sensor controller 31 and the stylus pen 2 via the sensor 30 is performed, for example, by an active electrostatic capacitance method. The active electrostatic capacitance method is a communication method that performs signal transmission and reception via capacitive coupling between the sensor electrode group constituting the sensor 30 and the pen tip electrode 10 of the stylus pen 2. Hereinafter, the signal sent by the sensor controller 31 to the stylus pen 2 via the sensor 30 is referred to as an "uplink signal US", and the signal sent by the stylus pen 2 to the sensor controller 31 via the sensor 30 is referred to as a "downlink signal DS".

[0059] Figure 2 is a diagram showing the timing of receiving and sending the uplink signal US and the downlink signal DS. As shown in the figure, the sensor controller 31 is configured to communicate with the stylus pen 2 in units of frames F of a predetermined time length, and at the beginning of each frame F, a plurality of X electrodes or a plurality of Y electrodes are used to send the uplink signal US. The uplink signal US sent in this way has the function of notifying the stylus pen 2 of the time position of the frame F and the timing (time slot) at which the stylus pen 2 should send the downlink signal DS. The stylus pen 2 detects the time position of the frame F based on the reception timing of the uplink signal US, and uses the time slot notified by the uplink signal US among the plurality of time slots contained therein to send the downlink signal DS.

[0060] Figure 3(a) is a diagram showing the structure of the uplink signal US. As shown in the figure, the uplink signal US is composed of a preamble PRE and a command COM. The preamble PRE is a part used for the stylus pen 2 to detect the uplink signal US, and is composed of a specified code string. On the other hand, the command COM is a part containing a command from the sensor controller 31 to the stylus pen 2, and is composed of a code string representing the command.

[0061] The symbol string is composed of one or more symbols. Each symbol can be information corresponding to "0" or "1" as shown in the figure, or information corresponding to a multi-bit bit string, or information not corresponding to a bit string (for example, information used only to indicate the position of the preamble PRE). Each symbol is sent using a spread spectrum code with autocorrelation characteristics.

[0062] Figure 3 (b) is a diagram showing an example of such a spread spectrum code. In this figure, examples of a spread spectrum code corresponding to code symbol "0" and a spread spectrum code corresponding to code symbol "1" are shown. The spread spectrum code of this example is composed of a code chip string (pseudo-random number), and the code chip string is composed of 32 code chips. However, the number of code chips that constitute one spread spectrum code is not limited to 32. In addition, in this example, the spread spectrum code corresponding to code symbol "1" becomes a spread spectrum code obtained by inverting the spread spectrum code corresponding to code symbol "0". In the following description, the time length Tc of each code chip shown in the figure is referred to as the "code chip length", and the inverse of the code chip length Tc 1 / Tc is referred to as the "code chip rate".

[0063] The sensor controller 31 transmits the uplink signal US by supplying a pulse signal representing these spread spectrum codes to the sensor 30. In this case, the value of each code chip is represented by the voltage of the pulse signal. However, a carrier signal (sine wave signal) of a specified frequency may be transmitted instead of the pulse signal, in which case the value of each code chip is represented by the phase of the carrier signal.

[0064] The sensor controller 31 of the present embodiment is configured to be able to send an uplink signal US having a prescribed preamble PRE through any of a plurality of different settings. These settings may be settings in which the chip lengths (chip rates) are different from each other, or settings in which the frequencies of the carrier signals are different from each other, or settings in which the combinations of chips constituting the spread spectrum codes corresponding to each symbol (i.e., the types of spread spectrum codes) are different from each other. The larger the chip length (i.e., the smaller the chip rate), the lower the frequency of the carrier signal, and the shorter the spread spectrum code, the smaller the load on the sensor controller 31 involved in the transmission of the uplink signal US. The number of settings for the uplink signal US may be 2, or may be 3 or more. The following description will be continued using the example of the first setting and the second setting in which the chip lengths are different from each other.

[0065] The sensor controller 31 is configured to select either the first setting or the second setting, and to send the uplink signal US through the setting of the selected one. Furthermore, it is configured to determine whether the stylus pen 2 has failed in detecting the transmitted uplink signal US, and if it is determined to have failed, to send the uplink signal US through the setting of the other party. The selection of the setting may be based on the result of the communication with the stylus pen 2 implemented using the short-range wireless communication (second communication method) described later, or may be based on the response from the stylus pen 2 to the transmitted uplink signal US (the content of the downlink signal DS). For details of the above content, refer to the flow chart showing the processing of the sensor controller 31 later. Figure 1 Explain in detail again.

[0066] return Figure 2 . The downlink signal DS may include a position signal for the sensor controller 31 to detect the pen position and a data signal modulated by the pen data sent to the sensor controller 31. The sensor controller 31 uses a plurality of X electrodes and a plurality of Y electrodes constituting the sensor 30 to receive the position signal respectively, approximates the distribution of the received intensity of the position signal in the x direction and the y direction respectively by a normal distribution curve, derives the respective peak positions, and thereby derives the pen position. In addition, the sensor controller 31 uses an X electrode or a Y electrode closest to the pen position derived immediately before to receive the data signal, performs demodulation, and thereby obtains the pen data sent by the stylus pen 2. The pen data thus obtained may include, in addition to the response to the command in the uplink signal US, a pen pressure value indicating the pressure applied to the pen tip of the stylus pen 2 and switch information indicating the on / off state of a switch provided on the surface of the stylus pen 2.

[0067] return Figure 1 The main processor 32 is a central processing unit of the position detection device 3 having a function of controlling each unit of the position detection device 3. The main processor 32 is configured to execute various application programs including a drawing application program in addition to the operating system of the position detection device 3 by executing a program stored in a built-in memory.

[0068] The series of reports supplied by the sensor controller 31 to the main processor 32 are used by the main processor 32 for processing by the operating system and the drawing application. These processes include the generation and display of digital ink, movement of the cursor, and detection of various gestures such as tapping and dragging.

[0069] The wireless communication unit 33 is a device for communicating with other devices including the stylus pen 2 by short-range wireless communication such as Bluetooth (registered trademark). The main processor 32 is configured to be able to communicate with the stylus pen 2 via the wireless communication unit 33 by short-range wireless communication.

[0070] Next, let's focus on the stylus 2. The stylus 2 is a pen-shaped device, such as Figure 1 As shown in FIG. 1 , the stylus pen 2 is configured to include a pen tip electrode 10 and a wireless communication unit 11. The pen tip electrode 10 is an electrode used to receive an uplink signal US and transmit a downlink signal DS by capacitive coupling with the X electrode and the Y electrode in the sensor 30. The wireless communication unit 11 is a device for communicating with other devices including the position detection device 3 by short-range wireless communication such as Bluetooth (registered trademark). The stylus pen 2 is configured to be able to communicate with the position detection device 3 by short-range wireless communication via the wireless communication unit 11.

[0071] Figure 4 1 is a diagram showing the internal structure of the stylus pen 2. As shown in the figure, the stylus pen 2 is configured to have a pressure sensor 12, a communication unit 13, and an MCU (Micro Controller Unit) 14 in addition to the above-mentioned pen tip electrode 10 and wireless communication unit 11. In addition to these, the stylus pen 2 also has a core body constituting the pen tip of the stylus pen 2, a storage battery for supplying operating power to each part in the stylus pen 2, a switch provided on the surface, a memory for storing identification information of the stylus pen 2, etc., but Figure 4 Illustration omitted.

[0072] The pen tip electrode 10 is configured to include a pen head 10a and a pen ring 10b. The pen head 10a is a rod-shaped electrode provided at the front end of the core body. On the other hand, the pen ring 10b is a ring-shaped electrode provided in a manner surrounding the core body. The stylus pen 2 is configured to receive an uplink signal US using one or both of the pen head 10a and the pen ring 10b, and to send a downlink signal DS from the pen head 10a and the pen ring 10b, respectively. The sensor controller 31 is configured to derive a position based on each of the downlink signal DS sent from the pen head 10a and the downlink signal DS sent from the pen ring 10b, and to obtain the position derived based on the downlink signal DS sent from the pen head 10a as the pen position, and on the other hand, to derive the tilt (tilt angle) of the stylus pen 2 based on the two derived positions.

[0073] The pressure sensor 12 is a sensor that detects the pressure applied to the tip of the stylus pen 2. The pressure value detected by the pressure sensor 12 is supplied to the MCU 14 as a pen pressure value. When the pen pressure value supplied from the pressure sensor 12 is a specified value (e.g., 0), the MCU 14 determines that the stylus pen 2 is not in contact with the panel surface 3a (hovering), and when the pen pressure value exceeds the specified value (e.g., 0), the MCU 14 determines that the stylus pen 2 is in contact with the panel surface 3a (touching). Hereinafter, the state in which the tip of the stylus pen 2 is in contact with the panel surface 3a is referred to as "pen touch".

[0074] The communication unit 13 is a functional unit that has the function of converting the uplink signal US (spread spectrum code) received by the pen tip electrode 10 into a symbol string and supplying it to the MCU 14, and the function of converting the downlink signal DS (symbol string) supplied from the MCU 14 into the same spread spectrum code as the uplink signal US and supplying it to the pen tip electrode 10. Figure 4 In the figure, only the functions related to the uplink signal US are illustrated.

[0075] One side reference Figure 4 While specifically describing the function of the communication unit 13 related to the uplink signal US, the communication unit 13 is configured to include an AD converter 20 , a custom logic circuit 21 , clock generators 22 and 23 , and a switch circuit 24 .

[0076] The AD converter 20 is a circuit that converts the analog signal received as the uplink signal US into a bit string of "1" or "0" by sampling the uplink signal US supplied from the pen tip electrode 10 at a predetermined sampling rate, quantizing and encoding, and supplies it to the custom logic circuit 21. The sampling rate of the AD converter 20 is set to a value faster than the chip rate of the uplink signal US. On the other hand, the time length of each bit of the bit string output from the AD converter 20 is set to the same value as the chip length of the uplink signal US.

[0077] The custom logic circuit 21 is a circuit including a correlator 21a that calculates a correlation value between an input bit string and a pre-stored predetermined bit string. The correlator 21a plays a role in detecting the spreading code of the code element constituting the uplink signal US by calculating a correlation value between the bit string supplied from the AD converter 20 and a pre-stored predetermined bit string (a bit string representing the spreading code). The custom logic circuit 21 generates a code element string based on the detection result of the correlator 21a and supplies it to the MCU 14.

[0078] The clock generator 22 is a circuit that generates a clock signal that oscillates with a period corresponding to the chip length involved in the above-mentioned first setting. In addition, the clock generator 23 is a circuit that generates a clock signal that oscillates with a period corresponding to the chip length involved in the above-mentioned second setting. The switch circuit 24 is a circuit that generates a clock signal generated by any one of the clock generators 22 and 23 under the control of the MCU14 and supplies it to the custom logic circuit 21. The custom logic circuit 21 and the correlator 21a perform the above-mentioned calculation of the correlation value, generation of the codeword string, and the like according to the clock signal supplied in this way. Therefore, in order for the codeword string output from the custom logic circuit 21 to be a codeword string that correctly reflects the uplink signal US, the period of the clock signal needs to be consistent with the codeword length of the uplink signal US.

[0079] The MCU 14 is a central processing unit of the stylus pen 2, and performs processing to generate a downlink signal DS based on the uplink signal US received from the sensor controller 31 and transmit it to the sensor controller 31. In addition, the MCU 14 also performs processing based on short-range wireless communication with the sensor controller 31 via the wireless communication unit 11. The MCU 14 also performs processing to control the switch circuit 24 in order to switch the type (setting) of the uplink signal US that can be received.

[0080] Figure 5 2 is a diagram showing the transition of the operation mode of the MCU 14. As shown in the diagram, the MCU 14 is configured to have four operation modes: a normal operation mode, a priority uplink continuous search mode, a non-priority uplink continuous search mode, and an autonomous operation mode.

[0081] The normal operation mode is a mode in which the uplink signal US is detected based on the code string supplied from the custom logic circuit 21, and the downlink signal is generated and sent according to the detected uplink signal US. When the MCU 14 has not yet detected the uplink signal US, it can also continuously perform the uplink signal US detection operation, but in order to save battery consumption, it is preferred to perform the uplink signal US detection operation intermittently (i.e., at predetermined intervals).

[0082] Here, as described above, the sensor controller 31 of the present embodiment transmits the uplink signal US in any one of the first setting and the second setting in which the chip lengths are different from each other. The MCU 14 stores any one of the settings as a "priority setting" in advance, and controls the switch circuit 24 in a manner of supplying a clock signal that oscillates at a period corresponding to the priority setting to the custom logic circuit 21 when operating in the normal operation mode. As a result, the custom logic circuit 21 can correctly convert the uplink signal US (hereinafter referred to as "priority uplink signal US") transmitted in the priority setting into a symbol string, and on the other hand, cannot correctly convert the uplink signal US (hereinafter referred to as "non-priority uplink signal US") transmitted in a setting that is not the priority setting (hereinafter referred to as "non-priority setting") into a symbol string. Therefore, the MCU 14 operating in the normal operation mode can detect the priority uplink signal US based on the symbol string supplied from the custom logic circuit 21, and on the other hand, cannot detect the non-priority uplink signal US.

[0083] The setting that MCU14 stores as the "priority setting" is predetermined. However, MCU14 can share the setting of the uplink signal US with the sensor controller 31 at any timing through short-range wireless communication via the wireless communication unit 11. When the setting of the uplink signal US is shared with the sensor controller 31, MCU14 stores the shared setting as the "priority setting".

[0084] When the MCU14 detects the uplink signal US during the operation in the normal operation mode, it continues the operation in the normal operation mode, and performs the transmission of the downlink signal DS corresponding to the detected uplink signal US, the detection of the next uplink signal US, etc. On the other hand, when the pen touch is detected based on the pen pressure value supplied from the pressure sensor 12 in the state where the uplink signal US is not detected, the MCU14 enters the priority uplink continuous exploration mode. The priority uplink continuous exploration operation mode is a mode in which the detection operation of the priority uplink signal US is immediately performed according to the detection of the pen touch, and is used to quickly detect the uplink signal US in the case where the uplink signal US cannot be detected despite the contact with the panel surface 3a, for example, due to the relationship of the detection interval of the uplink signal US. When the MCU14 detects the uplink signal US during the operation in the priority uplink continuous exploration mode, it returns to the normal operation mode, and performs the transmission of the downlink signal DS corresponding to the detected uplink signal US, the detection of the next uplink signal US, etc.

[0085] In the case where the uplink signal US cannot be detected even after the detection action of the priority uplink signal US is performed for a specified time in the priority uplink continuous exploration mode, the MCU14 enters the non-priority uplink exploration mode. The non-priority uplink exploration mode is a mode for attempting to detect the non-priority uplink signal US. The MCU14 entering the non-priority uplink exploration mode controls the switch circuit 24 by supplying a clock signal that oscillates with a period corresponding to the non-priority setting to the custom logic circuit 21. As a result, the MCU14 becomes capable of detecting the non-priority uplink signal US based on the code string supplied from the custom logic circuit 21. It should be noted that when there are more than three settings for the uplink signal US, the MCU14 can also try each setting other than the priority setting in turn in the non-priority uplink exploration mode.

[0086] The MCU14 that detects the uplink signal US in the non-priority uplink exploration mode uses the settings at this time to overwrite the priority settings and return to the normal operation mode. Thereafter, the non-priority settings so far are used as priority settings. On the other hand, the MCU14 that has not detected the uplink signal US in the non-priority uplink exploration mode also enters the self-operating mode. The self-operating mode is a mode in which the stylus 2 that has failed to receive the uplink signal US autonomously sends the downlink signal DS. The MCU14 that has entered the self-operating mode periodically detects the priority uplink signal US and sends the downlink signal DS on the basis of controlling the switching circuit 24 by supplying a clock signal that vibrates with a period corresponding to the priority setting to the custom logic circuit 21. The downlink signal DS sent in the self-operating mode becomes a special downlink signal DS that includes flag information indicating that the MCU14 has entered the self-operating mode.

[0087] When the uplink signal US is detected during the self-operation mode, MCU14 enters the normal operation mode. The processing performed by MCU14 in the normal operation mode is as described above. The downlink signal DS sent by MCU14 in the normal operation mode does not contain the above-mentioned flag information. In addition, when the uplink signal US is not detected during the self-operation mode, the MCU14 enters the priority uplink continuous exploration mode based on the pen pressure value supplied from the pressure sensor 12. The processing performed by MCU14 in the priority uplink continuous exploration mode is as described above.

[0088] Figure 6 2 is a flowchart showing the process executed by the sensor controller 31. Hereinafter, the process executed by the sensor controller 31 according to the present embodiment will be described in detail with reference to this figure.

[0089] The sensor controller 31 first determines whether there is a common setting based on short-range wireless communication (step S1). If it is determined that there is a common setting in the determination, the sensor controller 31 selects the common setting (step S2), and if it is determined that there is no common setting, the sensor controller 31 selects a predetermined setting (here, set to the first setting) (step S3).

[0090] Next, the sensor controller 31 transmits the uplink signal US with the selected setting (step S4), and then performs the receiving action of the downlink signal DS (step S5). Then, the sensor controller 31 determines whether the downlink signal DS is received as a result of the receiving action (step S6), and if it is determined that it is not received, it re-determines whether there is a common setting based on the short-range wireless communication (step S7). As a result, if it is determined that there is a common setting, it immediately returns to step S4, and if it is determined that there is no common setting, it selects a setting different from the current setting (step S8), and then returns to step S4. Thus, the sensor controller 31 continues to transmit the uplink signal US with the shared setting when there is a common setting based on the short-range wireless communication until the downlink signal DS is received, and if there is no common setting based on the short-range wireless communication, it alternately continues to perform the transmission of the uplink signal US based on the first setting and the transmission of the uplink signal US based on the second setting.

[0091] When it is determined in step S6 that the downlink signal DS is received, the sensor controller 31 determines whether the received downlink signal DS is the above-mentioned "special downlink signal DS" (step S9). As a result, when it is determined to be a "special downlink signal DS", the sensor controller 31 selects a setting different from the current setting (step S10) and returns to step S4. The determination of "special downlink signal DS" in step S9 means that the stylus pen 2 has failed in the detection of the transmitted uplink signal US and has entered the self-running mode. By executing steps S9 and S10, the possibility of enabling the stylus pen 2 to receive the uplink signal US again can be increased.

[0092] The sensor controller 31, which determines that it is not a "special downlink signal DS" in step S9, derives the position of the stylus pen 2 and obtains the pen data sent by the stylus pen 2 based on the received downlink signal DS (step S11), and outputs it to the main processor 32. Then, the sensor controller 31 sends the uplink signal US again with the selected setting (step S12), and performs the reception operation of the downlink signal DS (step S13).

[0093] Next, the sensor controller 31 determines whether the downlink signal DS is received (step S14). As a result, if it is determined that it is received, the sensor controller 31 determines whether the received downlink signal DS is the above-mentioned "special downlink signal DS" (step S15). As a result, if it is determined that it is a "special downlink signal DS", the sensor controller 31 selects a setting different from the current setting (step S16), and returns the processing to step S4. The determination of "special downlink signal DS" in step S15 means that the stylus pen 2 that normally detects the uplink signal US temporarily fails in the detection of the uplink signal US and enters the self-operating mode. By processing steps S15 and S16, the possibility of restoring such a stylus pen 2 to the normal operation mode can be increased. If it is determined that it is not a "special downlink signal DS" in step S15, the sensor controller 31 returns to step S11 and continues processing.

[0094] When it is determined in step S14 that the downlink signal DS is not received, the sensor controller 31 determines whether the non-reception state of the downlink signal DS has continued for a predetermined number of times (or a predetermined time) (step S17). As a result, if it is determined that it has not continued, the process returns to step S12 to continue, and if it is determined that it has continued, the process returns to step S1.

[0095] As described above, according to the position detection system 1 of the present embodiment, the sensor controller 31 can use the first setting and the second setting which are different from each other such as the chip length (chip rate) to send the uplink signal US, so that when it is possible to select, a low-speed operation can be selected. Therefore, the load of the sensor controller 31 can be reduced.

[0096] In addition, noise is sometimes superimposed on the uplink signal US, and as a result, the reception of the uplink signal US in the stylus 2 is sometimes hindered. However, according to the position detection system 1 of the present embodiment, the sensor controller 31 can separately use the first setting and the second setting that are different from each other such as the code chip length (code chip rate) to send the uplink signal US, thereby reducing the impact of the noise in the reception of the uplink signal US by the stylus 2.

[0097] In addition, according to the position detection system 1 of the present embodiment, when the stylus pen 2 fails to detect the uplink signal US sent in the first setting, the sensor controller 31 can detect this and send the uplink signal US in the second setting. Therefore, the sensor controller 31 can start communication with the stylus pen 2 appropriately while sending the uplink signal US using any one of two or more different settings.

[0098] As mentioned above, although the preferred embodiment of the present invention has been described, the present invention is not limited to such embodiment at all, and the present invention can be implemented in various forms within the scope not departing from the gist of the present invention.

[0099] For example, in the above embodiment, an example of using short-range wireless communication without capacitive coupling with the pen tip electrode 10 in order to share the setting of the uplink signal US between the sensor controller 31 and the stylus pen 2 is described, but an electrode other than the sensor electrode group constituting the sensor 30 may be provided in the position detection device 3, and the setting of the uplink signal US may be shared between the sensor controller 31 and the stylus pen 2 via capacitive coupling between the electrode and the pen tip electrode 10. Examples of such electrodes include sensor electrodes constituting a touch panel provided in a notebook computer and electrodes provided in a pen compartment for storing the stylus pen 2.

[0100] In addition, in the above-mentioned embodiment, an example is described in which the stylus pen 2 enters the non-priority uplink exploration mode and attempts to receive the non-priority uplink signal US when it fails to receive the priority uplink signal US in the normal mode and the priority uplink continuous exploration mode. However, the stylus pen 2 may alternatively perform the reception action of the priority uplink signal US and the reception action of the non-priority uplink signal US, for example when the uplink signal US has not yet been detected.

[0101] In addition, in the above-mentioned embodiment, an example is described in which the sensor controller 31 sends an uplink signal US through any one of two or more different settings, but it is also possible to send more than two uplink signals US that are different at a higher level. In one example, the uplink signal US of one party can be sent through a certain version of the active electrostatic method, and the uplink signal US of the other party can be sent through a different version of the active electrostatic method. In addition, the uplink signal US of one party can be sent through the active electrostatic method, and the uplink signal US of the other party can be sent through other communication methods such as short-range wireless communication and electromagnetic induction. If both the case of sending more than two uplink signals US with different settings and the case of sending more than two uplink signals US with a level higher than the setting are called "sending the uplink signal US through any one of two or more different methods", if "setting" is replaced with "method" in the above-mentioned embodiment, the same effect as the above-mentioned embodiment can be obtained through the same processing.

Claims

1. A sensor controller, wherein: The sensor controller is configured to be able to transmit an uplink signal having a predetermined preamble code by using either a first setting or a second setting that are different from each other. Either the first configuration or the second configuration is selected, and the uplink signal is transmitted using the selected configuration.

2. The sensor controller according to claim 1, wherein: The first setting is a setting in which the chip rate of the spreading code constituting the uplink signal is relatively large, The second setting is a setting in which the chip rate of the spreading code constituting the uplink signal is relatively small.

3. The sensor controller according to claim 1, wherein: Either the first setting or the second setting is selected based on a response from the stylus pen to the transmitted uplink signal.

4. The sensor controller according to claim 1, wherein: Transmission of the uplink signal based on the first configuration and transmission of the uplink signal based on the second configuration are performed alternately.

5. The sensor controller according to claim 1, wherein: The selection of one of the first setting and the second setting is performed based on a result of communication with the stylus pen performed using a second communication method different from the first communication method used in transmission of the uplink signal.

6. The sensor controller according to claim 5, wherein: The first communication method is a communication method performed via capacitive coupling between a sensor electrode group arranged in the touch surface and a pen tip electrode of the stylus pen, The second communication method is a communication method not via the capacitive coupling.

7. The sensor controller according to claim 5, wherein: The first communication method is a communication method performed via capacitive coupling between a sensor electrode group arranged in the touch surface and a pen tip electrode of the stylus pen, The second communication method is a communication method performed via capacitive coupling between an electrode different from the sensor electrode group and the pen tip electrode.

8. A stylus pen, wherein: The stylus pen includes a receiving unit configured to detect both an uplink signal transmitted in a first setting and an uplink signal transmitted in a second setting different from the first setting.

9. The stylus pen according to claim 8, wherein: The receiving unit alternately performs a reception operation of an uplink signal transmitted in the first configuration and a reception operation of an uplink signal transmitted in the second configuration.

10. The stylus pen according to claim 8, wherein: The receiving unit selects either the first setting or the second setting based on the result of communication with the sensor controller using a second communication method different from the first communication method used in sending the uplink signal, and performs a receiving operation of the uplink signal sent with the setting of the selected one.

11. The stylus pen according to claim 10, wherein: The first communication method is a communication method performed via capacitive coupling between a sensor electrode group arranged in the touch surface and connected to the sensor controller and a pen tip electrode of the stylus pen, The second communication method is a communication method not via the capacitive coupling.

12. The stylus pen according to claim 10, wherein: The first communication method is a communication method performed via capacitive coupling between a sensor electrode group arranged in the touch surface and connected to the sensor controller and a pen tip electrode of the stylus pen, The second communication method is a communication method performed via capacitive coupling between an electrode different from the sensor electrode group and the pen tip electrode.

13. A sensor controller, wherein: sending a first uplink signal in a first manner, determining whether the stylus fails in detecting the first uplink signal, When it is determined that the stylus has failed in detecting the first uplink signal, a second uplink signal is transmitted using a second method different from the first method.

14. The sensor controller according to claim 13, wherein: When a special downlink signal is received after the first uplink signal is transmitted, it is determined that the stylus has failed in detecting the first uplink signal.

15. The sensor controller according to claim 14, wherein: The special downlink signal is a signal including information indicating that the stylus pen has entered the self-running mode.

16. The sensor controller according to claim 13, wherein: The first mode and the second mode are modes in which the frequency of an uplink signal or the chip length of a spreading code constituting the uplink signal is different from each other.

17. The sensor controller according to claim 13, wherein: The first method and the second method are methods in which the types or chip lengths of spreading codes constituting uplink signals are different from each other.

18. The sensor controller according to claim 13, wherein: The first method and the second method are methods in which electrodes used for transmitting uplink signals are different from each other.

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