Sensor controller, electronic apparatus, and position detection method

Abstract

The present invention pertains to a sensor controller, an electronic apparatus, and a position detection method. A sensor controller (22A) is provided with: a scan control unit (66) that executes a plurality of types of operation modes in which pen-scanning and touch-scanning on a touch sensor (20) are repeated in a time-division manner; and a signal transmission unit (68) that transmits an uplink signal (US) via a plurality of sensor electrodes (20X, 20Y) during execution of the pen-scanning. While a passive pointer (16) is not detected by the touch-scanning, the signal transmission unit (68) lowers the frequency of transmission of the uplink signal (US), as compared with the case when the passive pointer (16) is detected.

Description

Sensor controller, electronic device, and position detection method

[0001] The present invention relates to a sensor controller, an electronic device, and a position detection method.

[0002] Conventionally, a position detection system has been known that is composed of an active electronic pen (hereinafter simply referred to as an "active pen"), which is a self-powered position indicator, and an electronic device equipped with a touch sensor. In this type of system, signals are sent and received between the active pen and the electronic device to exchange data or synchronize control. In the following, to distinguish between the two types of signals, the signal from the electronic device will be referred to as an "uplink signal" and the signal from the active pen will be referred to as a "downlink signal."

[0003] Japanese Patent Application Laid-Open Publication No. 2021-043640 discloses a touch controller that operates in an uplink power saving mode in which the power required for transmitting an uplink signal is reduced in response to receiving a suspend command from a host computer, and returns to normal mode in response to detecting a predetermined trigger while operating in the uplink power saving mode.

[0004] Japanese Patent Application Laid-Open No. 2021-043640

[0005] However, in the touch controller disclosed in JP 2021-043640 A, if the host computer cannot send a suspend command for some reason, it will be unable to transition from normal mode to power saving mode.

[0006] The present invention has been made in consideration of such problems, and its purpose is to provide a sensor controller, electronic device, and position detection method that can voluntarily reduce the power consumption associated with detecting an indicated position depending on the detection state of the touch sensor.

[0007] The sensor controller in a first aspect of the present invention is a controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar form, and comprises a scan control unit that executes a plurality of types of operation modes, in which a pen scan for detecting an active pen that transmits a downlink signal and a touch scan for detecting a passive pointer that does not transmit the downlink signal are repeated in a time-division manner via the plurality of sensor electrodes, and a signal transmission unit that transmits an uplink signal to request the downlink signal via the plurality of sensor electrodes while the pen scan is being executed, and the signal transmission unit reduces the frequency of transmitting the uplink signal while the passive pointer is not detected by the touch scan compared to when the passive pointer is detected.

[0008] An electronic device according to a second aspect of the present invention includes a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar shape, and the above-described sensor controller connected to the touch sensor.

[0009] A position detection method in a third aspect of the present invention is a method using a sensor controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar form, in which the sensor controller executes an execution step of repeatedly executing a pen scan to detect an active pen that transmits a downlink signal and a touch scan to detect a passive pointer that does not transmit the downlink signal via the plurality of sensor electrodes in a time-division manner, and a transmission step of transmitting an uplink signal to request the downlink signal via the plurality of sensor electrodes while the pen scan is being executed, in which the transmission step reduces the frequency of transmission of the uplink signal while the passive pointer is not detected by the touch scan compared to when the passive pointer is detected.

[0010] A fourth aspect of the present invention provides a sensor controller that is connected to a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar shape, and includes a detection processing unit that repeatedly performs touch scans including specific drive operations via the plurality of sensor electrodes to detect a passive pointer that does not transmit a signal, and a drive modification unit that modifies drive parameters related to the specific drive operations so that the specific drive operations are performed less frequently or less frequently while the passive pointer is not detected by the touch scan than when the passive pointer is detected.

[0011] An electronic device according to a fifth aspect of the present invention includes a capacitive touch sensor having a plurality of sensor electrodes arranged in a plane, and the above-described sensor controller connected to the touch sensor.

[0012] A position detection method in a sixth aspect of the present invention is a method using a sensor controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar shape, in which the sensor controller executes an execution step of repeatedly executing a touch scan including a specific drive operation via the plurality of sensor electrodes, which is a scan for detecting a passive pointer that does not transmit a signal, and a modification step of modifying drive parameters related to the specific drive operation so that the specific drive operation is executed less frequently or the amount of the specific drive operation is reduced while the passive pointer is not detected by the touch scan, compared to when the passive pointer is detected.

[0013] According to the present invention, it is possible to voluntarily reduce the power consumption associated with the detection of the pointed position in accordance with the detection state of the touch sensor.

[0014] 1. is an overall configuration diagram of a position detection system incorporating an electronic device common to each embodiment of the present invention. FIG. 2 is a diagram showing an example of the internal configuration of the electronic device of FIG. 1. FIG. 3 is a functional block diagram of a sensor controller in a first embodiment. FIG. 4 is a flowchart showing an example of detection operation by the sensor controller of FIG. 3. FIG. 5 is a detailed flowchart showing the first mode and the second mode (steps SP18, SP20) of FIG. 4. FIG. 6 is a diagram showing an example of an operation mode by the sensor controller. FIG. 7 is a time chart showing transmission of an uplink signal. FIG. 8 is a diagram showing an example of settings related to transmission of an uplink signal or reception of a downlink signal. FIG. 9 is a flowchart of a first modified example of the first embodiment. FIG. 10 is a detailed flowchart of a second modified example of the first embodiment. FIG. 11 is a functional block diagram of a sensor controller in a second embodiment. FIG. 12 is a diagram showing a schematic diagram of a touch detection method using an orthogonal code sequence. FIG. 13 is a flowchart showing an example of detection operation by the sensor controller of FIG. 11. FIG. 14 is a diagram showing a schematic diagram of a drive operation of the sensor controller in a state where a touch is not detected. FIG. 15 is a diagram showing a schematic diagram of a drive operation of the sensor controller in a state where a touch is detected. FIG. 16 is a diagram showing a first example of a difference in behavior between the first and second drive operations. FIG. 17 is a diagram showing a second example of a difference in behavior between the first and second drive operations. 11 is a diagram showing a third example of a difference in behavior between the first and second driving operations. FIG. 12 is a flowchart showing another example of a detection operation by the sensor controller of FIG.

[0015] The sensor controller, electronic device, and position detection method of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments and modifications described below, and can be freely modified without departing from the spirit and scope of the present invention. Alternatively, the respective configurations may be combined arbitrarily as long as no technical contradictions arise. Alternatively, the execution or execution order of each step constituting the flowchart may be changed as long as no technical contradictions arise. Alternatively, the term "part" may be replaced with other terms, such as unit, module, device, or element.

[0016] 1 is a diagram showing the overall configuration of a position detection system 10 incorporating an electronic device 12 common to all embodiments of the present invention. The position detection system 10 is basically composed of the electronic device 12 and an electronic pen 14 (corresponding to an "active pen") used together with the electronic device 12.

[0017] The electronic device 12 may be, for example, a tablet terminal with or without a display function, a smartphone, or a personal computer. If the electronic device 12 is a liquid crystal tablet, the user can write pictures or characters on the electronic device 12 by holding the electronic pen 14 in one hand and pressing the pen tip against the touch surface 12s and moving it. The user can also perform desired operations via the displayed user controls by touching the touch surface 12s with their own finger 16 (corresponding to a "passive pointer").

[0018] The electronic pen 14 is a pen-shaped pointing device configured to be capable of bidirectional communication with the electronic device 12. Hereinafter, a signal transmitted from the electronic device 12 to the electronic pen 14 will be referred to as an "uplink signal," and a signal transmitted from the electronic pen 14 to the electronic device 12 will be referred to as a "downlink signal." The electronic pen 14 is an "active type" stylus that actively generates a signal from electrical energy stored in itself and transmits this signal to the electronic device 12 as a downlink signal.

[0019] <Circuit Configuration of Sensor Controller 22> Fig. 2 is a diagram showing an example of the internal configuration of the electronic device 12 of Fig. 1. The electronic device 12 includes a touch sensor 20, a sensor controller 22, and a host processor 24.

[0020] The touch sensor 20 is a capacitance-type (more specifically, mutual capacitance-type) sensor having a plurality of sensor electrodes 20X and 20Y arranged in a planar shape. The touch sensor 20 includes a plurality of sensor electrodes 20X for detecting a position in the X direction (X coordinate) and a plurality of sensor electrodes 20Y for detecting a position in the Y direction (Y coordinate). The sensor electrodes 20X and 20Y may be made of a transparent conductive material including ITO (indium tin oxide) or a wire mesh. The sensor electrodes 20X and 20Y are insulated from each other by an insulating substrate (not shown) made of glass or resin.

[0021] The linear sensor electrodes 20X extend in the Y direction and are spaced apart at equal intervals along the X direction. The linear sensor electrodes 20Y extend in the X direction and are spaced apart at equal intervals along the Y direction. The touch sensor 20 may be a self-capacitance sensor in which block-shaped electrodes are arranged in a two-dimensional lattice pattern, instead of the mutual capacitance sensor described above. The touch sensor 20 may be a "built-in type" (further classified as an on-cell type or an in-cell type) sensor that is integrated with a display panel (not shown), or an "external type" (or out-cell type) sensor that is attached to the display panel from the outside.

[0022] The sensor controller 22 is connected to the touch sensor 20 and includes a micro control unit (hereinafter referred to as MCU 30), a logic unit 31, a first transmission unit 32, a second transmission unit 33, a receiving unit 34, and a selection unit 35.

[0023] The MCU 30 and the logic unit 31 control the transmission and reception operations of the sensor controller 22 by controlling the first transmission unit 32, the second transmission unit 33, the reception unit 34, and the selection unit 35. The MCU 30 is a control unit that reads and executes a program from its own memory to selectively perform, for example, the following operations: [1] supplying a pixel drive voltage Vcom to the selection unit 35; [2] controlling the first transmission unit 32 to transmit a finger detection signal FDS; [3] controlling the reception unit 34 to receive the finger detection signal FDS; [4] controlling the second transmission unit 33 to transmit an uplink signal US to the electronic pen 14; and [5] controlling the reception unit 34 to receive a downlink signal DS from the electronic pen 14. The logic unit 31 is configured to generate control signals for the first transmission unit 32, the second transmission unit 33, the reception unit 34, and the selection unit 35 in accordance with the control of the MCU 30.

[0024] When the downlink signal DS is a "position signal" indicating the position of the electronic pen 14, the MCU 30 calculates the position coordinates (x, y) of the electronic pen 14 on the touch surface 12s from the reception strength at each of the plurality of sensor electrodes 20X, 20Y, and outputs the calculated coordinates to the host processor 24. On the other hand, when the downlink signal DS is a "data signal" including transmission data, the MCU 30 acquires response data Res (specifically, a unique ID, writing pressure, on / off information of the pen switch, etc.) included in the data signal and outputs the response data Res to the host processor 24.

[0025] The first transmission unit 32 is a circuit that generates a finger detection signal FDS under the control of the MCU 30 and supplies it to each sensor electrode 20X through a selection unit 35. The finger detection signal FDS is, for example, a signal s １ ~s Ｋ The signal s １ ~s Ｋ Each n-th (n=1 to K) pulse is a pulse group p ｎ and one pulse group p ｎ The pulses constituting the signal are input in parallel from the first transmitter 32 through the selector 35 to the sensor electrodes 20X.

[0026] The second transmitter 33 has a function of generating the uplink signal US under the control of the MCU 30 and the logic unit 31. Specifically, the second transmitter 33 is configured to include a code string holding unit 40, a spreading processing unit 41, and a transmission guard unit 42.

[0027] The code sequence holding unit 40 has a function of generating and holding a spreading code of a predetermined chip length having autocorrelation characteristics, based on a control signal ctrl_t3 supplied from the logic unit 31. The spreading code held by the code sequence holding unit 40 is supplied to a spreading processing unit 41.

[0028] The spreading processing unit 41 has a function of acquiring a transmission chip sequence of a predetermined chip length by modulating the spreading code held by the code sequence holding unit 40 based on the command COM supplied via the MCU 30. The spreading processing unit 41 supplies the acquired transmission chip sequence to the selection unit 35 via the transmission guard unit 42.

[0029] The transmission guard unit 42 has the function of inserting a guard period (i.e., a period during which neither transmission nor reception is performed) required to switch between transmission and reception operations between the transmission period of the uplink signal US and the reception period of the downlink signal DS based on the control signal ctrl_t4 supplied from the logic unit 31.

[0030] The receiving unit 34 is a circuit that receives the finger detection signal FDS transmitted by the first transmitting unit 32 or the downlink signal DS transmitted by the electronic pen 14 based on the control signal ctrl_r from the logic unit 31. Specifically, the receiving unit 34 includes an amplifier circuit 45, a detection circuit 46, and an analog-to-digital (AD) converter 47.

[0031] The amplifier circuit 45 amplifies and outputs the finger detection signal FDS or the downlink signal DS supplied from the selector 35. The detector circuit 46 is a circuit that generates a voltage corresponding to the level of the output signal of the amplifier circuit 45. The AD converter 47 is a circuit that generates a digital signal by sampling the voltage output from the detector circuit 46 at predetermined time intervals. The digital signal output by the AD converter 47 is supplied to the MCU 30.

[0032] The selection unit 35 is connected to the touch sensor 20, and performs a switching operation in response to a control signal from the logic unit 31. Specifically, the selection unit 35 includes two switches 48x and 48y and two electrode selection circuits 49x and 49y.

[0033] Each of switches 48x and 48y is a switch element configured to connect a common terminal to one of the T1 terminal, T2 terminal, R terminal, and D terminal. The common terminal of switch 48x is connected to electrode selection circuit 49x, the T1 terminal is connected to the output terminal of first transmission unit 32, the T2 terminal is connected to the output terminal of second transmission unit 33, the R terminal is connected to the input terminal of reception unit 34, and the D terminal is connected to the output terminal of MCU 30. The common terminal of switch 48y is connected to electrode selection circuit 49y, the T terminal is connected to the output terminal of second transmission unit 33, and the R terminal is connected to the input terminal of reception unit 34.

[0034] The electrode selection circuit 49x is a switch element for selectively connecting the plurality of sensor electrodes 20X to the common terminal of the switch 48x. That is, the electrode selection circuit 49x is configured to be able to simultaneously connect at least some of the plurality of sensor electrodes 20X to the common terminal of the switch 48x. The electrode selection circuit 49y is a switch element for selectively connecting the plurality of sensor electrodes 20Y to the common terminal of the switch 48y. That is, the electrode selection circuit 49y is configured to be able to simultaneously connect at least some of the plurality of sensor electrodes 20Y to the common terminal of the switch 48y.

[0035] The selection unit 35 is supplied with four control signals sTRx, sTRy, selX, and selY from the logic unit 31. Specifically, the control signal sTRx is supplied to the switch 48x, the control signal sTRy is supplied to the switch 48y, the control signal selX is supplied to the electrode selection circuit 49x, and the control signal selY is supplied to the electrode selection circuit 49y. The logic unit 31 performs switching control of the selection unit 35 via the four control signals sTRx, sTRy, selX, and selY, thereby selectively performing [1] transmission and reception of a finger detection signal FDS, or [2] transmission of an uplink signal US and reception of a downlink signal DS.

[0036] The host processor 24 is configured with an arithmetic processing device including a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and an MPU (Micro-Processing Unit). The host processor 24 executes programs stored in a memory (not shown) to execute the operating system of the electronic device 12 and various applications such as drawing software. The drawing software includes a function for generating stroke data based on coordinates sequentially supplied from the sensor controller 22, rendering the data, and displaying the data on a display, and a function for adjusting the rendering results based on data such as pen pressure values ​​supplied from the sensor controller 22 (for example, a function for adjusting line width according to pen pressure values).

[0037] First Embodiment First, a sensor controller 22A according to a first embodiment will be described with reference to Figures 3 to 8. This sensor controller 22A corresponds to one aspect of the sensor controller 22 shown in Figure 2.

[0038] 3 is a functional block diagram of the sensor controller 22A in the first embodiment. The sensor controller 22A includes a position detection unit 60, an output processing unit 62, and a mode control unit 64.

[0039] The position detection unit 60 detects the position of the electronic pen 14 or finger 16 through transmission and reception via the touch sensor 20 (more specifically, the plurality of sensor electrodes 20X, 20Y). Specifically, the position detection unit 60 includes a scan control unit 66, a signal transmission unit 68, a signal acquisition unit 70, a touch detection unit 72, and a pen detection unit 74.

[0040] The scan control unit 66 repeatedly executes multiple types of scan processing in a time-division manner via the touch sensor 20. The multiple types of scan processing include [1] a "touch scan" for detecting a passive pointer (e.g., a finger 16) that does not transmit a signal, and [2] a "pen scan" for detecting an electronic pen 14 that transmits a downlink signal DS. The touch scan and the pen scan may be executed at a ratio of 1:1 or at a ratio of n:m (n≠m).

[0041] The above-described touch scan is performed to detect a change in capacitance between the sensor electrodes 20X and 20Y. This touch scan may be, for example, [1] a scan based on a "mutual capacitance method" in which a finger detection signal FDS is transmitted from the sensor electrode 20X and the signal FDS is received by the sensor electrode 20Y to detect a change in mutual capacitance between the sensor electrodes 20X and 20Y, or [2] a scan based on a "self-capacitance method" in which a change in capacitance between the sensor electrodes 20X and 20Y is detected.

[0042] The touch scan operation modes are classified into [1] a "normal mode" for detecting touches under normal conditions and [2] a "special mode" for detecting touches under special conditions. Examples of special modes include a foreign object mode and a glove mode. The "foreign object mode" refers to an operation mode for detecting touches at locations where foreign objects (e.g., water droplets or coins) are present on the touch surface 12s of the electronic device 12. For example, by relatively lowering the threshold value used in threshold processing compared to the normal mode, it becomes easier to detect touches on conductive foreign objects. The "glove mode" refers to an operation mode for detecting touches while wearing gloves when the user is wearing gloves. For example, by applying a high-pass filter that passes the high-frequency band of the detection signal, it becomes easier to detect touches while wearing gloves.

[0043] The pen scan operation modes described above are classified into [1] a "global scan" that detects the presence and position of the electronic pen 14 over the entire sensor area formed by the touch sensor 20, and [2] a "local scan" that detects the presence and position of the electronic pen 14 within a portion of the sensor area. For example, when the electronic pen 14 is detected by the global scan, the local scan is performed within a range limited to the closest detection position of the electronic pen 14 or the periphery of the detection position, with high positional accuracy.

[0044] The pen scan operation modes include [1] an "active detection mode" for detecting an electronic pen 14 that transmits a downlink signal DS (i.e., an active pen), or [2] a "passive detection mode" for detecting an electronic pen 14 that does not transmit a downlink signal DS or has stopped transmitting (i.e., a passive pen). The pen scan operation modes also include [3] an "in-phase mode" for continuously transmitting in-phase uplink signals US, or [4] a "phase inversion mode" for alternately transmitting positive-phase and negative-phase signals of the uplink signal US.

[0045] The signal transmitting unit 68 transmits a desired signal for performing a touch scan or a pen scan from the sensor electrodes 20X, 20Y in accordance with transmission control by the scan control unit 66. During touch scanning, the signal transmitting unit 68 generates a signal for detecting the finger 16 (here, a finger detection signal FDS) and outputs and transmits this finger detection signal FDS to a transmitting electrode (here, one or more sensor electrodes 20X). During pen scanning, the signal transmitting unit 68 generates a signal for detecting the electronic pen 14 (here, an uplink signal US) and outputs and transmits this uplink signal US to a transmitting electrode (here, one or more sensor electrodes 20X, 20Y).

[0046] The signal transmitting unit 68 is configured to transmit the uplink signal US in accordance with driving parameters corresponding to the operation mode selected by the mode control unit 64. Examples of the driving parameters include [1] the length of a time slot allocated to a touch scan (hereinafter also referred to as "touch time length"), [2] the length of a time slot allocated to a pen scan (hereinafter also referred to as "pen time length"), or [3] the transmission rate of the uplink signal US. For example, the signal transmitting unit 68 changes at least one of the touch time length, the pen time length, and the transmission rate so that the frequency of transmission of the uplink signal US decreases while the finger 16 is detected by the touch scan compared to when the finger 16 is not detected.

[0047] Other examples of the drive parameters include [1] the transmission voltage of the uplink signal US, [2] the number of transmission electrodes, or [3] the length of the orthogonal code sequence formed by the uplink signal US. "Transmission electrodes" refer to the sensor electrodes 20X, 20Y used to transmit the uplink signal US. "Orthogonal code sequences" may include not only pure orthogonal code sequences but also pseudo orthogonal code sequences.

[0048] The signal acquisition unit 70 receives or acquires a desired signal for performing a touch scan or a pen scan from the sensor electrodes 20X, 20Y in accordance with reception control by the scan control unit 66. During execution of a touch scan, the signal acquisition unit 70 receives a finger detection signal FDS from the transmitting electrode via a receiving electrode (here, one or more sensor electrodes 20Y) and acquires a detection signal (or a first detection signal) for detecting the presence or position of the finger 16. During execution of a pen scan, the signal acquisition unit 70 receives a downlink signal DS from the electronic pen 14 via a receiving electrode (here, one or more sensor electrodes 20X, 20Y) and acquires a detection signal (or a second detection signal) for detecting the presence or position of the electronic pen 14.

[0049] The signal acquisition unit 70 is configured to receive the downlink signal DS in accordance with drive parameters corresponding to the operation mode selected by the mode control unit 64. Examples of the drive parameters include [1] the length of the time slot allocated to the touch scan (i.e., the touch time length), [2] the length of the time slot allocated to the pen scan (i.e., the pen time length), or [3] the reception rate of the downlink signal DS. For example, while the finger 16 is detected by the touch scan, the signal acquisition unit 70 changes at least one of the touch time length, the pen time length, and the reception rate so that the frequency of receiving the downlink signal DS decreases compared to when the finger 16 is not detected.

[0050] The touch detection unit 72 calculates the presence or absence or position (hereinafter also collectively referred to as "touch position") of a passive pointer (here, finger 16) by performing various signal processing on the first detection signal acquired by the signal acquisition unit 70. This signal processing includes: [1] "threshold processing" that detects the presence or absence of the finger 16 from the magnitude relationship between the signal value for each position indicated by the signal distribution and a threshold; [2] "identification processing" that identifies the type of touch (e.g., finger 16, palm, or other object) based on the size or shape of the area detected by the threshold processing; and [3] "position calculation processing" that calculates the touch position by performing an interpolation operation or an approximation operation on the signal distribution.

[0051] The pen detection unit 74 calculates the presence or position (hereinafter collectively referred to as "pen position") of the active pen (here, the electronic pen 14) by performing various signal processing on the second detection signal acquired by the signal acquisition unit 70. This signal processing includes [1] "threshold processing" that detects the presence or absence of the electronic pen 14 from the magnitude relationship between the signal value for each position indicated by the signal distribution and a threshold, or [2] "position calculation processing" that calculates the pen position by performing an interpolation or approximation operation on the signal distribution.

[0052] The output processing unit 62 generates position information including the pen position or touch position calculated by the position detection unit 60, and then outputs data including the position information to the host processor 24 ( FIG. 2 ). The output processing unit 62 may output data at a predetermined cycle (e.g., 120 Hz). In addition to the position information of the electronic pen 14, this data may also include: [1] information provided by the electronic pen 14 (e.g., pen ID, writing pressure, pen switch on / off information, etc.); [2] information calculated from the position information (e.g., tilt angle, orientation, speed, acceleration); and [3] identification information of the currently executing operation mode.

[0053] The mode control unit 64 switches between and executes a plurality of operation modes that combine touch scanning or pen scanning. Examples of operation modes include [1] an "STP (Simultaneous Pen Touch) mode" in which the positions of the electronic pen 14 and the finger 16 are detected in a time-division manner, and [2] an "exclusive mode" in which detection of the finger 16 is temporarily stopped and the position of only the electronic pen 14 is detected. For example, in the STP mode, various combinations can be selected regarding the "type" of time slots that make up the repeated operation unit, the "ratio" of the number of time slots, and the "duration" of the time slots.

[0054] The mode control unit 64 may select and execute the first mode while the finger 16 is detected, and the second mode while the finger 16 is not detected. Here, the "first mode" refers to an operation mode in which the touch scan time slot is assigned to a first touch time length and the pen scan time slot is assigned to a first pen time length. The "second mode" refers to an operation mode in which the touch scan time slot is assigned to a second touch time length and the pen scan time slot is assigned to a second pen time length.

[0055] The execution period of the second mode (hereinafter referred to as the second execution period) may be the same as or different from the execution period of the first mode (hereinafter referred to as the second execution period). When both execution periods are the same, the second touch time length is the first touch time length minus a predetermined amount, and the second pen time length is the first pen time length plus a predetermined amount. This predetermined amount is a positive value smaller than the value of the first touch time length.

[0056] In the second mode, the transmission frequency or transmission voltage of the uplink signal US is relatively reduced in exchange for extending the pen time length. Examples of the transmission frequency include [1] the transmission rate or [2] the number of transmissions within a time slot. The "transmission rate" is defined as the number of transmissions of the uplink signal US per unit time. The "number of transmissions within a time slot" is defined as the product of the pen time length and the transmission rate.

[0057] Here, the transmission rate in the first mode is defined as the "first transmission rate," the number of transmissions within a time slot in the first mode as the "first transmission count," the transmission rate in the second mode as the "second transmission rate," and the number of transmissions within a time slot in the second mode as the "second transmission count." In this case, [1] the second transmission rate may be set to be smaller than the first transmission rate, or [2] the second transmission count may be set to be smaller than the first transmission count. In particular, it is preferable that the ratio of the second transmission count to the first transmission count be 0.3 or greater and less than 1.

[0058] <Overall Operation> The sensor controller 22A in the first embodiment is configured as described above. Next, the detection operation by the sensor controller 22A will be described with reference to the flowchart in FIG.

[0059] In step SP10, the mode control unit 64 of the sensor controller 22A checks whether the detection timing has arrived. If the detection timing has not yet arrived (step SP10: NO), the sensor controller 22A remains in step SP10 until the detection timing arrives. On the other hand, if the detection timing has arrived (step SP10: YES), the sensor controller 22A proceeds to the next step SP12.

[0060] In step SP12, the mode control unit 64 acquires the detection results obtained by the previous touch scan and pen scan (that is, the previous detection results).

[0061] In step SP14, the mode control unit 64 checks whether the electronic pen 14 was detected in the previous pen scan by referring to the detection result acquired in step SP12. If the electronic pen 14 was not detected (step SP14: NO), the mode control unit 64 proceeds to the next step SP16.

[0062] In step SP16, the mode control unit 64 refers to the detection result acquired in step SP12 and checks whether or not a touch by the finger 16 was detected in the previous touch scan. If a touch was detected (step SP16: YES), the mode control unit 64 supplies a mode flag indicating the first mode to the position detection unit 60 (more specifically, the scan control unit 66), and proceeds to the next step SP18.

[0063] In step SP18, the position detection unit 60 of the sensor controller 22A performs detection processing in the first mode selected in step SP 16. Thereafter, the sensor controller 22A returns to step SP10, and repeatedly executes steps SP10, SP12, SP14, SP16, and SP18 while the first mode remains selected.

[0064] Returning to step SP16, if no touch was detected in the previous touch scan (step SP16: NO), the mode control unit 64 supplies a mode flag indicating the second mode to the position detection unit 60 (more specifically, the scan control unit 66) and proceeds to the next step SP20.

[0065] In step SP18, the position detection unit 60 performs detection processing in the second mode selected in step SP 16. Thereafter, the sensor controller 22A returns to step SP10, and repeatedly executes steps SP10, SP12, SP14, SP16, and SP20 while the second mode remains selected.

[0066] Returning to step SP14, if the electronic pen 14 was detected in the previous pen scan (step SP14: YES), the mode control unit 64 supplies a mode flag indicating the third mode to the position detection unit 60 (more specifically, the scan control unit 66) and proceeds to the next step SP22.

[0067] In step SP22, the position detection unit 60 performs detection processing in the third mode selected in step SP 14. Thereafter, the sensor controller 22A returns to step SP10 and repeatedly executes steps SP10, SP12, SP14, and SP22 while the third mode remains selected.

[0068] In this way, the sensor controller 22A repeatedly executes steps SP10 to SP22 to detect the indicated position (here, the touch position and the pen position) in real time.

[0069] <Explanation of First and Second Modes> Next, the detection process in the first mode (step SP18) or the second mode (step SP20) shown in FIG. 4 will be described in detail with reference to the flowchart in FIG.

[0070] In step SP30, the scan control unit 66 controls the signal transmission unit 68 to transmit and the signal acquisition unit 70 to receive, thereby performing touch scanning via the plurality of sensor electrodes 20X and 20Y.

[0071] In step SP32, the signal acquisition unit 70 acquires a first detection signal corresponding to the touch scan executed in step SP30.

[0072] In step SP34, the touch detection unit 72 calculates the touch position from the first detection signal acquired in step SP32.

[0073] In step SP36, the output processing unit 62 generates position information including the touch position calculated in step SP34, and supplies data including the position information to the host processor 24. After the touch scan is completed, the position detection unit 60 proceeds to the next step SP38.

[0074] In step SP38, the scan control unit 66 performs a global scan via the multiple sensor electrodes 20X, 20Y by controlling transmission of the signal transmitting unit 68 and receiving of the signal acquiring unit 70. Prior to this transmission and reception control, drive parameters corresponding to the first mode or the second mode are set.

[0075] In step SP40, the signal acquisition unit 70 acquires a second detection signal corresponding to the global scan executed in step SP38.

[0076] In step SP42, the pen detection unit 74 calculates the pen position from the second detection signal acquired in step SP40.

[0077] In step SP44, the output processing unit 62 generates position information including the pen position calculated in step SP42, and supplies data including this position information to the host processor 24. In this way, the sensor controller 22A ends the detection process in the first mode or the second mode.

[0078] 6 is a diagram showing an example of an operation mode of the sensor controller 22 A. The sensor controller 22 A (more specifically, the mode control unit 64) switches to operate in any one of the first mode, the second mode, and the third mode.

[0079] The first mode corresponds to an operation mode in which one touch scan (TS) and one global scan (GS) are executed in a time-division manner. The touch scan time slot is assigned a time length of T1 (unit: ms). The global scan time slot is assigned a time length of T2 (unit: ms). In other words, [1] a touch scan with a time length of T1 and [2] a global scan with a time length of T2 constitute one operation unit (period: Tc1 = T1 + T2).

[0080] The second mode corresponds to an operation mode in which one touch scan (TS) and one global scan (GS) are executed in a time-division manner, similar to the first mode. However, the second mode differs from the first mode in the time length allocation. The touch scan time slot is assigned a time length of T1-Δ (unit: ms). The global scan time slot is assigned a time length of T2+Δ (unit: ms). In other words, [1] a touch scan with a time length of (T1-Δ) and [2] a global scan with a time length of (T2+Δ) constitute one operation unit (period: Tc1=T1+T2).

[0081] The third mode corresponds to an operation mode in which one touch scan (TS) and two local scans (LS) are executed in a time-division manner. The touch scan time slot is assigned a time length of T1 (unit: ms). The local scan time slot is assigned a time length of T2 (unit: ms). In other words, [1] a touch scan with a time length of T1, [2] a local scan with a time length of T2, and [3] a local scan with a time length of T2 constitute one operation unit (period: Tc2 = T1 + 2 T2).

[0082] FIG. 7 is a time chart showing the transmission of the uplink signal US. Each rectangular pulse indicates the timing of transmission of the uplink signal US from a specific sensor electrode 20X. In the first mode, the uplink signal US is transmitted intermittently at a transmission rate of S1 [Hz], i.e., at a period of 1 / S1 [s], starting at time t = t0. In contrast, in the second mode, the uplink signal US is transmitted intermittently at a transmission rate of S2 [Hz], i.e., at a period of 1 / S2 [s], starting at time t = t0 - Δ. As a result, when performing one global scan, the number of transmissions of the uplink signal US is reduced in the second mode compared to the first mode. This allows for more time to be spent detecting the electronic pen 14 in the second mode, and also reduces the increase in power consumption due to the transmission of the uplink signal US.

[0083] 8 is a diagram showing an example of settings related to transmission of an uplink US signal or reception of a downlink signal DS. The transmission rate is set to a relatively high value in the first mode and a relatively low value in the second mode. The transmission voltage is set to a relatively high value in the first mode and a relatively low value in the second mode. The reception rate is set to a relatively high value in the first mode and a relatively low value in the second mode. The number of transmission electrodes is set to a relatively large value in the first mode and a relatively small value in the second mode. The length of the orthogonal code sequence is set to a relatively long value in the first mode and a relatively short value in the second mode. This allows a longer detection time for the electronic pen 14 in the second mode and suppresses an increase in power consumption due to transmission of the uplink signal US or reception of the downlink signal DS.

[0084] Regarding the number of transmitting electrodes, when a palm is detected by touch scanning, the number of transmitting electrodes at or near the palm position may be reduced even during execution of the first mode, thereby preventing the signal induced in the electronic pen 14 from temporarily becoming undetectable due to fluctuations in the reference potential caused by signals induced in the human body via the palm.

[0085] Summary of First Embodiment As described above, the electronic device 12 in the first embodiment includes a capacitive touch sensor 20 including a plurality of sensor electrodes 20X, 20Y arranged in a planar manner, and a sensor controller 22, 22A connected to the touch sensor 20. The sensor controller 22A includes a scan control unit 66 that executes a plurality of operation modes, repeating a pen scan to detect an active pen (here, the electronic pen 14) that transmits a downlink signal DS and a touch scan to detect a passive pointer (here, the finger 16) that does not transmit a downlink signal DS, on the plurality of sensor electrodes 20X, 20Y in a time-division manner, and a signal transmission unit 68 that transmits an uplink signal US via the sensor electrodes 20X, 20Y to request the downlink signal DS during the pen scan. The signal transmission unit 68 reduces the frequency of transmission of the uplink signal US while the finger 16 is not detected by the touch scan compared to when the finger 16 is detected.

[0086] In addition, in the position detection method of the first embodiment, the sensor controller 22A executes an execution step (SP18, SP20) in which pen scans and touch scans are repeatedly executed on a plurality of sensor electrodes 20X, 20Y in a time-division manner, and a transmission step (SP30) in which an uplink signal US is transmitted via the sensor electrodes 20X, 20Y while the pen scan is being executed, and in the transmission step, the frequency of transmission of the uplink signal US is reduced while a finger 16 is not detected by the touch scan compared to when a finger 16 is detected.

[0087] In this way, while the finger 16 is not detected by the touch scan, the frequency of transmitting the uplink signal US is relatively reduced, so that the power consumption associated with detecting the pointing position can be voluntarily reduced when the touch sensor 20 is in a detection state, particularly when the finger 16 is not detected.

[0088] Furthermore, if the multiple types of operation modes include a first mode in which the touch scan time slot is assigned to a first touch time length (T1) and the pen scan time slot is assigned to a first pen time length (T2), and a second mode in which the touch scan time slot is assigned to a second touch time length (T1-Δ) and the pen scan time slot is assigned to a second pen time length (T2+Δ), the scan control unit 66 may select the first mode while the finger 16 is detected, and select and execute the second mode while the finger 16 is not detected. This allows for a longer period of time to be spent detecting the electronic pen 14 by executing the second mode when the finger 16 is not detected.

[0089] The second touch time length may be the first touch time length (T1) minus a predetermined amount (Δ), and the second pen time length may be the first pen time length (T2) plus a predetermined amount (Δ). This allows the execution cycle of the scan operation unit to be kept constant even if there is a mode transition between the first mode and the second mode.

[0090] Furthermore, when the number of times the uplink signal US is transmitted per unit time in the first mode is defined as a first transmission rate (S1), and the number of times the uplink signal US is transmitted per unit time in the second mode is defined as a second transmission rate (S2), the product of the second pen time length (T2-Δ) and the second transmission rate (S2) may be smaller than the product of the first pen time length (T2) and the first transmission rate (S1). This ensures a longer detection time for the electronic pen 14 in the second mode, and suppresses an increase in power consumption due to the transmission of the uplink signal US.

[0091] The pen scan may also be a global scan for detecting the electronic pen 14 over the entire sensor area of ​​the touch sensor 20. In particular, the global scan widens the search range, which increases the probability of detecting the electronic pen 14.

[0092] Furthermore, while the finger 16 is not detected by the touch scan, the signal transmission unit 68 may (1) lower the transmission voltage of the uplink signal US, (2) reduce the number of sensor electrodes 20X, 20Y used to transmit the uplink signal US, or (3) shorten the orthogonal code sequence used to encode the uplink signal US, compared to when the finger 16 is detected. This allows the power consumption associated with detecting the pointing position to be reduced autonomously when the finger 16 is not detected.

[0093] The sensor controller 22A further includes a signal acquisition unit 70 that receives downlink signals DS from the plurality of sensor electrodes 20X, 20Y during execution of a pen scan to acquire the downlink signals DS. The signal acquisition unit 70 may receive the downlink signals DS less frequently while a finger 16 is not detected by a touch scan than when a finger 16 is detected. This makes it possible to autonomously reduce power consumption associated with detection of the pointing position when a finger 16 is not detected.

[0094] <First Modification> Figure 9 is a flowchart of a first modification of the first embodiment. Figure 9 differs from the flowchart of Figure 4 in that steps SP24 and SP26 have been added. The operations in steps SP10 to SP22 are the same as those in Figure 4, so a description thereof will be omitted.

[0095] In step SP14 of FIG. 9, if the electronic pen 14 is not detected (step SP14: NO), the mode control unit 64 of the sensor controller 22A proceeds to step SP24 before proceeding to step SP16.

[0096] In step SP24, the mode control unit 64 checks whether a specific condition is met. Examples of the specific condition include: (1) a disconnection of at least one of the sensor electrodes 20X and 20Y is detected; (2) the passive detection mode is being executed by the scan control unit 66; or (3) a special mode (such as the foreign substance attachment mode or glove mode) is being executed by the scan control unit 66.

[0097] If the specific condition is not satisfied (step SP24: NO), the mode control unit 64 proceeds to step SP16 and performs touch detection processing (step SP16). On the other hand, if the specific condition is satisfied, the mode control unit 64 supplies a mode flag indicating the fourth mode to the position detection unit 60 (more specifically, the scan control unit 66) and proceeds to the next step SP26.

[0098] In step SP26, the position detection unit 60 of the sensor controller 22A performs detection processing in the fourth mode selected in step SP24. When transmitting the uplink signal US, the signal transmission unit 68 [1] increases the transmission frequency, [2] increases the transmission voltage, [3] increases the number of transmitting electrodes, or [4] lengthens the orthogonal code sequence, compared to the case of any of the first to third modes.

[0099] Thereafter, the sensor controller 22A returns to step SP10 and repeatedly executes steps SP10, SP12, SP14, SP16, SP24, and SP26 while the fourth mode is continuously selected.

[0100] In this way, when a specific condition is satisfied, the signal transmitter 68 may increase the frequency of transmission of the uplink signal US, increase the transmission voltage, increase the number of transmitting electrodes, or lengthen the orthogonal code sequence compared to when the specific condition is not satisfied, thereby increasing the possibility of detecting the electronic pen 14 through pen scanning even in conditions where it is difficult to detect the electronic pen 14.

[0101] <Second Modification> Fig. 10 is a flowchart of a second modification of the first embodiment, which corresponds to a detailed flowchart of step SP22 (detection processing in the third mode) in Fig. 4 .

[0102] In step SP50 of FIG. 10, the position detection unit 60 acquires the position information of the electronic pen 14 in the most recent pen scan.

[0103] In step SP52, the position detection unit 60 refers to the position information acquired in step SP50 and checks whether a proximity condition (hereinafter also referred to as a "proximity condition") is satisfied, which indicates a state in which the electronic pen 14 is in proximity to or in contact with the touch sensor 20. Examples of the proximity condition include: [1] the reception strength of the downlink signal DS exceeds a threshold, or [2] the writing pressure value detected by a writing pressure sensor (not shown) is non-zero.

[0104] If the proximity condition is not met (step SP52: NO), the position detection unit 60 proceeds to step SP54, whereas if the proximity condition is met (step SP52: YES), the position detection unit 60 proceeds to step SP56.

[0105] In step SP54, the position detection unit 60 performs the same or corresponding detection process as in the first mode, and then ends the operation of the flowchart shown in Fig. 10. For example, when transmitting the uplink signal US, the signal transmission unit 68 relatively increases the transmission voltage or relatively increases the length of the orthogonal code sequence.

[0106] In step SP56, the position detection unit 60 refers to the position information acquired in step SP50 and checks the magnitude relationship between the tilt angle of the electronic pen 14 and the threshold value. If the tilt angle is less than the threshold value (step SP56: NO), the position detection unit 60 performs detection processing that is the same as or corresponds to the first mode (step SP54), and then ends the operation of the flowchart shown in Fig. 10. On the other hand, if the tilt angle is equal to or greater than the threshold value (step SP56: YES), the position detection unit 60 proceeds to the next step SP58.

[0107] In step SP58, the position detection unit 60 performs the same or corresponding detection process as in the second mode, and then ends the operation of the flowchart shown in Fig. 10. For example, when transmitting the uplink signal US, the signal transmission unit 68 relatively lowers the transmission voltage or relatively shortens the length of the orthogonal code sequence.

[0108] In this way, when a proximity condition indicating that the electronic pen 14 is in proximity to or in contact with the touch sensor 20 is satisfied, the signal transmitting unit 68 may change the transmission voltage or the length of the orthogonal code sequence of the uplink signal US depending on the tilt angle of the electronic pen 14.

[0109] For example, the signal transmitting unit 68 may decrease the transmission voltage of the uplink signal US or shorten the orthogonal code sequence as the tilt angle of the electronic pen 14 increases. Conversely, the signal transmitting unit 68 may increase the transmission voltage of the uplink signal US or lengthen the orthogonal code sequence as the tilt angle of the electronic pen 14 decreases. In a situation where there is a high probability that the electronic pen 14 is being used and the electronic pen 14 is easily detected, it is possible to voluntarily reduce power consumption associated with detection.

[0110] Alternatively, when the proximity condition is no longer satisfied, the signal transmitter 68 may increase the transmission voltage of the uplink signal US or lengthen the orthogonal code sequence. When the electronic pen 14 is farther away from the touch sensor 29 and is difficult to detect, the detection sensitivity of the electronic pen 14 can be increased voluntarily.

[0111] Second Embodiment Next, a sensor controller 22B according to a second embodiment will be described with reference to Figures 11 to 19. This sensor controller 22B corresponds to one aspect of the sensor controller 22 shown in Figure 2.

[0112] A sensor controller that drives Tx electrodes in parallel tends to consume more power than a sensor controller that drives Tx electrodes in serial. In particular, when driving an on-cell touch panel with a large load capacitance (e.g., 1000 pF) in parallel, the power consumption becomes significantly larger, which can cause heat generation within the on-cell touch panel. Therefore, it is desirable to reduce the power consumption associated with the driving operation of the touch sensor 20.

[0113] <Functional Block Diagram> Fig. 11 is a functional block diagram of the sensor controller 22B in the second embodiment. The sensor controller 22B includes a detection processing unit 100 and a drive change unit 102. Note that, although components related to the detection function of the electronic pen 14 are omitted in Fig. 11, the sensor controller 22B may be configured to include a pen detection function, as in the first embodiment (Fig. 3).

[0114] The detection processing unit 100 repeatedly executes touch scans, which are scans for detecting a passive pointer that does not transmit a signal (e.g., the hand 18 in FIG. 15 ), and include specific drive operations, via the plurality of sensor electrodes 20X, 20Y. Specifically, the detection processing unit 100 includes a signal transmitting unit 104, a signal acquiring unit 106, a touch detecting unit 108, and an output processing unit 110.

[0115] The signal transmitting unit 104 generates a signal for detecting the hand 18 (i.e., a finger detection signal FDS) during execution of a touch scan, and outputs and transmits this finger detection signal FDS to a transmitting electrode (here, one or more sensor electrodes 20X). The signal transmitting unit 104 is configured to be able to generate and transmit the finger detection signal FDS in accordance with drive parameters supplied by the drive changing unit 102. Examples of the drive parameters include: [1] electrode information for specifying the position, spacing, or number of sensor electrodes 20X used as transmitting electrodes; [2] code information for specifying multiple orthogonal code sequences formed by the finger detection signal FDS; or [3] a transmission voltage of the finger detection signal FDS.

[0116] During touch scanning, the signal acquisition unit 106 receives finger detection signals FDS from the transmitting electrodes (here, one or more sensor electrodes 20X) via the receiving electrodes (here, one or more sensor electrodes 20Y) and acquires detection signals for detecting the hand 18. The signal acquisition unit 106 is configured to be able to receive or acquire the finger detection signals FDS in accordance with the drive parameters supplied by the drive change unit 102. Examples of the drive parameters include [1] electrode information for specifying the position, spacing, or number of sensor electrodes 20Y used as receiving electrodes, or [2] the number of samples when performing statistical processing on the detection signals.

[0117] The touch detection unit 108 performs various signal processing on the detection signal acquired by the signal acquisition unit 106 to calculate the presence or absence or position (i.e., touch position) of the hand 18. This signal processing includes threshold processing, identification processing, or position calculation processing, as in the first embodiment (the touch detection unit 72 in FIG. 3 ).

[0118] The output processing unit 110 generates position information including the touch position calculated by the touch detection unit 108, and then outputs data including the position information to the host processor 24 (FIG. 2). The output processing unit 110 is configured to be able to output the generated data in accordance with the drive parameters supplied by the drive change unit 102. An example of the drive parameters is the number of outputs per unit time (i.e., output rate).

[0119] The drive change unit 102 changes drive parameters related to a specific drive operation included in the touch scan. Specifically, while a passive pointer (e.g., a hand 18) is not detected by the touch scan, the drive change unit 102 changes the drive parameters so that the specific drive operation is performed less frequently or less frequently than when the hand 18 is detected.

[0120] The drive change unit 102 may classify the sensor electrodes 20X, 20Y constituting the touch sensor 20 into a plurality of electrode groups and set drive parameters corresponding to each electrode group. The electrode groups may include, for example, a "first electrode group" that is a collection of the sensor electrodes 20X, 20Y corresponding to a detection position where the hand 18 is detected or the vicinity of the detection position, and a "second electrode group" that is a collection of the sensor electrodes 20X, 20Y corresponding to a position where the hand 18 is not detected. For example, when a detection value correlated with the amount of change in capacitance most recently obtained by touch scanning exceeds a threshold, the drive change unit 102 may classify the sensor electrodes 20X, 20Y at a position corresponding to the detection value into the first electrode group, whereas when the detection value does not exceed the threshold, the drive change unit 102 may classify the sensor electrodes 20X, 20Y at a position corresponding to the detection value into the second electrode group.

[0121] In this case, the drive change unit 102 may set a first drive parameter for the first electrode group that results in a relatively high frequency of execution of a specific drive operation or a relatively large amount of execution of a specific drive operation, and may set a second drive parameter for the second electrode group that results in a relatively low frequency of execution of a specific drive operation or a relatively small amount of execution of a specific drive operation.

[0122] Examples of "specific driving operations" include: (1) an output process that outputs data including the detected position of the hand 18 to the outside; (2) a statistical process that performs statistical calculations on multiple sample values ​​obtained through touch scanning; (3) a transmission process that transmits a finger detection signal FDS to the sensor electrode 20X; and (4) a transmission process that receives a finger detection signal FDS from the sensor electrode 20Y.

[0123] As a first example, the drive parameters may include the number of outputs per unit time in the output process, in which case the drive change unit 102 sets a relatively large number of outputs for the first electrode group as the first drive parameter, and sets a relatively small number of outputs for the second electrode group as the second drive parameter.

[0124] As a second example, the drive parameters may include the number of samples in the statistical processing, in which case the drive change unit 102 sets a relatively large number of samples for the first electrode group as the first drive parameter and sets a relatively small number of samples for the second electrode group as the second drive parameter.

[0125] As a third example, the drive parameters may include multiple orthogonal code sequences (here, this includes not only pure orthogonal code sequences but also pseudo orthogonal code sequences) formed by the finger detection signal FDS. In this case, the drive change unit 102 sets different orthogonal code sequences as first drive parameters for each of the sensor electrodes 20X belonging to the first electrode group, and sets a common orthogonal code sequence as second drive parameters for two or more sensor electrodes 20X belonging to the second electrode group.

[0126] As a fourth example, the drive parameters may include the number or usage rate of the sensor electrodes 20X used in the transmission process. In this case, the drive change unit 102 sets a relatively large number or usage rate for the first electrode group as the first drive parameter, and sets a relatively small number or usage rate for the second electrode group as the second drive parameter.

[0127] As a fifth example, the drive parameters may include the number or usage rate of the sensor electrodes 20Y used in the reception process. In this case, the drive change unit 102 sets a relatively large number or usage rate for the first electrode group as the first drive parameter, and sets a relatively small number or usage rate for the second electrode group as the second drive parameter.

[0128] 12 is a diagram illustrating a touch detection method using an orthogonal code sequence. When the number of sensor electrodes 20X is four, the signal s １ ~s Ｋ Each of the signal S1 and signal S4 is composed of four pulses represented by "1" or "-1". Specifically, as shown in FIG. 12, the signal S1 is composed of "1, 1, 1, 1", the signal S2 is composed of "1, 1, -1, -1", the signal S3 is composed of "1, -1, -1, 1", and the signal S4 is composed of "1, -1, 1, -1". The sensor electrode 20Y １ and four sensor electrodes 20X １ ~20X ４ The capacitance formed between each of these is represented by C １１ ~C ４１ Let's say.

[0129] Pulse group {p ｉ} (i=1 to 4) stored in the shift register 112. ｉ} is a vector of capacitances and a set of pulses {p ｉ The correlator 114 calculates the dot product of the four pulse groups {p ｉ}, the level {L ｉ} and the correlation value {T ｉ As a result, in the example of FIG. １ = 4 C ４１ , T ２= 4 C ３１ , T ３ = 4 C ２１ , T ４ = 4 C １１ In this way, the correlation value {T ｉ}, the touch position can be detected.

[0130] <Overall Operation> The sensor controller 22B in the second embodiment is configured as described above. Next, the detection operation by the sensor controller 22B will be described with reference to the flowchart in FIG.

[0131] 13, the sensor controller 22B checks whether the detection timing has arrived. If the detection timing has not yet arrived (step SP60: NO), the sensor controller 22B remains in step SP60 until the detection timing arrives. On the other hand, if the detection timing has arrived (step SP60: YES), the sensor controller 22B proceeds to the next step SP62.

[0132] In step SP62, the drive change section 102 acquires the detection result obtained by the previous touch scan (that is, the previous detection result).

[0133] In step SP64, the drive change unit 102 sets drive parameters based on the detection results acquired in step SP62, and supplies the drive parameters to the detection processing unit 100.

[0134] In step SP66, the detection processing unit 100 performs detection processing using both the first and second drive operations in accordance with the drive parameters set in step SP64. Thereafter, the sensor controller 22B returns to step SP60 and repeatedly executes steps SP60 to SP66 to perform detection of the indicated position (here, the touch position) in real time.

[0135] <Specific Examples of Driving Operations> Next, specific examples of the first and second driving operations performed in step SP66 of FIG. 13 will be described with reference to FIGS.

[0136] 14 is a diagram schematically illustrating the drive operation of the sensor controller 22B when no touch is detected. Here, it is assumed that, of the sensor electrodes 20X and 20Y that constitute the touch sensor 20, the sensor electrode 20X is used as a transmitting electrode (Tx electrode) and the sensor electrode 20Y is used as a receiving electrode (Rx electrode). When no touch is detected by the touch sensor 20, a uniform drive operation (i.e., a first drive operation) is performed on all of the corresponding sensor electrodes 20X.

[0137] FIG. 15 is a diagram schematically illustrating the drive operation of the sensor controller 22B when a touch is detected. Specifically, FIG. 15 corresponds to a diagram illustrating a transition from the state shown in FIG. 14 to a state in which a touch by a user's hand 18 (e.g., two fingers) is detected. The multiple sensor electrodes 20X are dynamically classified into two electrode groups according to the positional relationship of the touch by the hand 18. The single-hatched sensor electrodes 20X are classified into a first electrode group indicating "touched." The remaining double-hatched sensor electrodes 20X are classified into a second electrode group indicating "not touched." As a result, a first drive operation is performed on the six sensor electrodes 20X belonging to the first electrode group, and a second drive operation is performed on the eight sensor electrodes 20X belonging to the second electrode group.

[0138] As a result, when one touch scan is performed, the second drive operation is performed less frequently or the amount of the second drive operation is smaller than that of the first drive operation, which may result in a partial degradation of touch detection performance in the second drive operation, but on the other hand, reduces power consumption due to the specific drive operation.

[0139] FIG. 16 is a diagram illustrating a first example of the difference in behavior between the first and second drive operations. In the example of FIG. 16, the first and second drive operations are operations related to output processing that outputs data including the detected position of the hand 18 to the outside. For example, the first drive operation performs touch scanning (TS) at an output rate of 120 Hz, while the second drive operation performs touch scanning (TS) at an output rate of 60 Hz (half of 120 Hz). In this case, power consumption due to the data output processing is reduced through the second drive operation. Note that the second drive operation slightly reduces the time responsiveness of the detection result at the time of touch, but switching to the first drive operation immediately after touch by the hand 18 makes it less susceptible to the influence of the time responsiveness. Note that the first and second drive operations may be selectively performed as described above, or alternatively, may be performed in a time-division manner.

[0140] FIG. 17 illustrates a second example of the difference in behavior between the first and second drive operations. In the example of FIG. 17, the first and second drive operations are operations related to statistical processing of multiple sample values ​​obtained through touch scanning. For example, the first drive operation acquires four frames of signal distribution data D1 to D4, and calculates a signal distribution (or heat map) by averaging the four sample values. On the other hand, the second drive operation acquires two frames of signal distribution data D1 and D3, half of the total, and calculates a signal distribution by averaging the two sample values. In this case, the second drive operation reduces power consumption due to the number of samplings. Note that the second drive operation causes statistical variation in the detection results at the time of touch, but switching to the first drive operation immediately after touch by the hand 18 reduces the impact of statistical variation.

[0141] FIG. 18 illustrates a third example of the difference in behavior between the first and second driving operations. In the example of FIG. 18, the first and second driving operations are operations related to a transmission process for outputting a finger detection signal FDS to the sensor electrode 20X. For example, in the first driving operation, an orthogonal code sequence OCS, i.e., N different orthogonal code sequences, is supplied in parallel to each sensor electrode 20X. On the other hand, in the second driving operation, a common orthogonal code sequence OCS, i.e., (N / m) different orthogonal code sequences (here, m = 2), is supplied to two adjacent sensor electrodes 20X. In this case, the second driving operation reduces power consumption due to the calculation of the capacitance value. Note that the second driving operation slightly reduces the spatial resolution of the detection result at the time of touch, but switching to the first driving operation immediately after touch by the hand 18 reduces the impact of the reduced spatial resolution.

[0142] FIG. 19 is a flowchart showing another example of the detection operation by the sensor controller 22B of FIG.

[0143] In step SP70, the sensor controller 22B checks whether the detection timing has arrived. If the detection timing has not yet arrived (step SP70: NO), the sensor controller 22B remains in step SP60 until the detection timing arrives. On the other hand, if the detection timing has arrived (step SP70: YES), the sensor controller 22B proceeds to the next step SP72.

[0144] In step SP72, the drive change section 102 acquires the detection result obtained by the previous touch scan (that is, the previous detection result).

[0145] In step SP74, the drive change unit 102 refers to the previous detection result acquired in step SP72 and checks whether or not a touch by the hand 18 has been detected. If a touch has been detected (step SP74: YES), the detection processing unit 100 proceeds to the next step SP76.

[0146] In step SP76, the detection processing unit 100 performs detection processing by the first drive operation in accordance with the first drive parameters. After that, the sensor controller 22B returns to step SP70 and repeatedly executes steps SP70, SP72, SP74, and SP76 while the touch is continuously detected.

[0147] Returning to step SP74, if no touch is detected (step SP74: NO), the detection processing unit 100 proceeds to the next step SP78.

[0148] In step SP76, the detection processing unit 100 performs detection processing by the second drive operation in accordance with the second drive parameters. After that, the sensor controller 22B returns to step SP70 and repeatedly executes steps SP70, SP72, SP74, and SP78 while a touch is still not detected.

[0149] In this way, the sensor controller 22B repeatedly executes steps SP70 to SP76 in FIG. 19, thereby detecting the indicated position (here, the touched position) in real time.

[0150] Summary of Second Embodiment As described above, the electronic device 12 in the second embodiment includes a capacitive touch sensor 20 including a plurality of sensor electrodes 20X, 20Y arranged in a planar shape, and sensor controllers 22, 22B connected to the touch sensor 20. The sensor controller 22B includes a detection processing unit 100 that repeatedly executes touch scans including a specific drive operation, which are scans for detecting a passive pointer (here, a hand 18) that does not transmit a signal, and a drive change unit 102 that changes drive parameters related to the specific drive operation so that the specific drive operation is executed less frequently or the amount of the specific drive operation is reduced while the hand 18 is not detected by the touch scan, compared to when the hand 18 is detected.

[0151] In addition, in the position detection method of the second embodiment, the sensor controller 22B executes an execution step (SP76, SP78) in which it repeatedly executes a touch scan including a specific drive operation, and a modification step in which it modifies the drive parameters related to the specific drive operation so that the specific drive operation is executed less frequently or the amount of the specific drive operation is reduced while the hand 18 is not detected by the touch scan compared to when the hand 18 is detected.

[0152] In this way, while a hand 18 is detected by touch scanning, the frequency of execution of a specific drive operation is reduced or the amount of execution of a specific drive operation is reduced compared to when a hand 18 is not detected, thereby making it possible to spontaneously reduce the power consumption associated with detecting the pointing position when the touch sensor 20 is in a detection state, particularly when a finger 16 is not detected.

[0153] Furthermore, the drive change unit 102 classifies the multiple sensor electrodes 20X, 20Y that constitute the touch sensor 20 into a first electrode group that is a collection of the sensor electrodes 20X, 20Y that correspond to a detection position where the hand 18 is detected or the vicinity of the detection position, and a second electrode group that is a collection of the sensor electrodes 20X, 20Y that correspond to a position where the hand 18 is not detected. The drive change unit 102 may then set, for the first electrode group, first drive parameters that result in a relatively high frequency of execution of a specific drive operation or a relatively large amount of execution of the specific drive operation, and set, for the second electrode group, second drive parameters that result in a relatively low frequency of execution of the specific drive operation or a relatively small amount of execution of the specific drive operation.

[0154] In addition, the drive change unit 102 may classify the sensor electrodes 20X, 20Y located at a position corresponding to the detection value most recently obtained by touch scanning, which correlates with the amount of change in capacitance, into a first electrode group when the detection value exceeds a threshold value, and may classify the sensor electrodes 20X, 20Y located at a position corresponding to the detection value into a second electrode group when the detection value does not exceed the threshold value.

[0155] Furthermore, the specific drive operation is an operation related to output processing that outputs data including the detected position of hand 18 to the outside, and the drive parameters may include the number of outputs per unit time in the output processing. In this case, drive change unit 102 may set a relatively large number of outputs for the first electrode group as the first drive parameter, and set a relatively small number of outputs for the second electrode group as the second drive parameter.

[0156] In addition, the specific driving operation may be an operation related to statistical processing of a plurality of sample values ​​obtained through touch scanning, and the driving parameters may include the number of samples in the statistical processing. In this case, the driving change unit 102 may set a relatively large number of samples as the first driving parameter for the first electrode group, and set a relatively small number of samples as the second driving parameter for the second electrode group.

[0157] Furthermore, the specific drive operation is an operation related to a transmission process for outputting a detection signal of the hand 18 to the sensor electrodes 20X, 20Y, and the drive parameters may include a plurality of orthogonal code sequences formed by the detection signals. In this case, the drive change unit 102 may set a different orthogonal code sequence as the first drive parameter for each sensor electrode belonging to the first electrode group, and set a common orthogonal code sequence as the second drive parameter for two or more sensor electrodes 20X, 20Y belonging to the second electrode group.

[0158] Furthermore, the specific drive operation is an operation related to a reception process for receiving a detection signal for the hand 18 from the sensor electrodes 20X, 20Y, and the drive parameters may include a usage rate of the sensor electrodes 20X, 20Y used in the reception process. In this case, the drive change unit 102 may set a relatively high usage rate for the first electrode group as the first drive parameter, and set a relatively low usage rate for the second electrode group as the second drive parameter.

[0159] [Explanation of symbols] 10. Input system, 12. Electronic device, 14. Electronic pen (active pen), 16. Finger (passive pointer), 18. Hand (passive pointer), 20. Touch sensor, 20X, 20Y. Sensor electrodes, 22, 22A, 22B. Sensor controller, 24. Host processor, 66. Scan control unit, 68. Signal transmission unit, 100. Detection processing unit, 102. Drive change unit, DS. Downlink signal, US. Uplink signal, FDS. Finger detection signal

Claims

1. A sensor controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar shape, comprising: a scan control unit that executes a plurality of types of operation modes in which a pen scan for detecting an active pen that transmits a downlink signal and a touch scan for detecting a passive pointer that does not transmit the downlink signal are repeated in a time-division manner via the plurality of sensor electrodes; and a signal transmission unit that transmits an uplink signal to request the downlink signal via the plurality of sensor electrodes while the pen scan is being executed, wherein the signal transmission unit reduces the frequency of transmitting the uplink signal while the passive pointer is not detected by the touch scan compared to when the passive pointer is detected.

2. The sensor controller of claim 1, wherein the multiple types of operating modes include: a first mode in which the touch scan time slot is assigned to a first touch time length and the pen scan time slot is assigned to a first pen time length; and a second mode in which the touch scan time slot is assigned to a second touch time length and the pen scan time slot is assigned to a second pen time length, and wherein the scan control unit selects and executes the first mode while the passive pointer is detected, and selects and executes the second mode while the passive pointer is not detected.

3. The sensor controller of claim 2, wherein the second touch time length is a value obtained by subtracting a predetermined amount from the first touch time length, and the second pen time length is a value obtained by adding the predetermined amount to the first pen time length.

4. The sensor controller of claim 3, wherein, when the number of times the uplink signal is transmitted per unit time in the first mode is defined as a first transmission rate, and the number of times the uplink signal is transmitted per unit time in the second mode is defined as a second transmission rate, the product of the second pen time length and the second transmission rate is smaller than the product of the first pen time length and the first transmission rate.

5. The sensor controller according to claim 1, wherein the pen scan is a global scan for detecting the active pen over an entire sensor area formed by the touch sensor.

6. The sensor controller of claim 1, wherein the signal transmission unit lowers the transmission voltage of the uplink signal, reduces the number of sensor electrodes used to transmit the uplink signal, or shortens the orthogonal code sequence used to encode the uplink signal while the passive pointer is not detected by the touch scan, compared to when the passive pointer is detected.

7. The sensor controller of claim 1, further comprising a signal acquisition unit that receives the downlink signals from the plurality of sensor electrodes and acquires the downlink signals while the pen scan is being performed, wherein the signal acquisition unit reduces the frequency of receiving the downlink signals while the passive pointer is not detected by the touch scan compared to when the passive pointer is detected.

8. The sensor controller of claim 1, wherein the signal transmission unit increases the frequency of transmitting the uplink signal, increases the transmission voltage of the uplink signal, increases the number of sensor electrodes used to transmit the uplink signal, or lengthens the orthogonal code sequence used to encode the uplink signal when a specific condition is satisfied, compared to when the specific condition is not satisfied.

9. The sensor controller of claim 8, wherein the specific condition includes: detection of an open circuit in at least one of the sensor electrodes; an operating mode for detecting a passive pen that does not transmit the downlink signal being executed by the scan control unit; or an operating mode for detecting the passive pointer under a special condition being executed by the scan control unit.

10. The sensor controller of claim 1, wherein the signal transmission unit changes the transmission voltage of the uplink signal or the length of the orthogonal code sequence used to encode the uplink signal in accordance with the tilt angle of the active pen when a proximity condition indicating that the active pen is in proximity to or in contact with the touch sensor is satisfied.

11. An electronic device comprising: a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar shape; and a sensor controller according to any one of claims 1 to 10, connected to the touch sensor.

12. A position detection method using a sensor controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar shape, wherein the sensor controller executes an execution step of repeatedly executing, in a time-division manner, a pen scan for detecting an active pen that transmits a downlink signal and a touch scan for detecting a passive pointer that does not transmit the downlink signal via the plurality of sensor electrodes, and a transmission step of transmitting, during the execution of the pen scan, an uplink signal for requesting the downlink signal via the plurality of sensor electrodes, wherein in the transmission step, the frequency of transmission of the uplink signal is reduced while the passive pointer is not detected by the touch scan compared to when the passive pointer is detected.

13. A sensor controller connected to a capacitive touch sensor consisting of a plurality of sensor electrodes arranged in a planar shape, comprising: a detection processing unit that repeatedly executes a touch scan including a specific drive operation via the plurality of sensor electrodes, the touch scan being a scan for detecting a passive pointer that does not transmit a signal; and a drive change unit that changes drive parameters related to the specific drive operation so that the specific drive operation is executed less frequently or the amount of the specific drive operation is reduced while the passive pointer is not detected by the touch scan, compared to when the passive pointer is detected.

14. The sensor controller of claim 13, wherein the drive change unit classifies the multiple sensor electrodes constituting the touch sensor into a first electrode group which is a collection of sensor electrodes corresponding to a detection position where the passive pointer is detected or the vicinity of the detection position, and a second electrode group which is a collection of sensor electrodes corresponding to a position where the passive pointer is not detected, sets a first drive parameter for the first electrode group which results in a relatively high frequency of execution of the specific drive operation or a relatively large amount of execution of the specific drive operation, and sets a second drive parameter for the second electrode group which results in a relatively low frequency of execution of the specific drive operation or a relatively small amount of execution of the specific drive operation.

15. The sensor controller of claim 14, wherein the drive change unit classifies the sensor electrodes at the positions corresponding to the detection value most recently obtained by the touch scan, which correlates with the amount of change in capacitance, into a first electrode group when the detection value exceeds a threshold value, and classifies the sensor electrodes at the positions corresponding to the detection value into a second electrode group when the detection value does not exceed the threshold value.

16. A sensor controller as described in claim 14, wherein the specific drive operation is an operation related to an output process that outputs data including the detected position of the passive pointer to the outside, the drive parameters include the number of outputs per unit time in the output process, and the drive change unit sets a relatively large number of outputs to the first electrode group as the first drive parameter, and sets a relatively small number of outputs to the second electrode group as the second drive parameter.

17. The sensor controller of claim 14, wherein the specific drive operation is an operation related to statistical processing that performs statistical calculations on multiple sample values ​​obtained through the touch scan, the drive parameters include a number of samples in the statistical processing, and the drive change unit sets a relatively large number of samples for the first electrode group as the first drive parameter, and sets a relatively small number of samples for the second electrode group as the second drive parameter.

18. The sensor controller of claim 14, wherein the specific drive operation is an operation related to a transmission process for outputting a detection signal of the passive pointer to the sensor electrode, the drive parameters include a plurality of orthogonal code sequences formed by the detection signals, and the drive change unit sets a different orthogonal code sequence as the first drive parameter for each of the sensor electrodes belonging to the first electrode group, and sets a common orthogonal code sequence as the second drive parameter for two or more of the sensor electrodes belonging to the second electrode group.

19. A sensor controller as described in claim 14, wherein the specific drive operation is an operation related to a transmission process of outputting a detection signal for the passive pointer to the sensor electrodes, the drive parameters include the number or usage rate of the sensor electrodes used in the transmission process, and the drive change unit sets a relatively large number or usage rate for the first electrode group as the first drive parameter, and sets a relatively small number or usage rate for the second electrode group as the second drive parameter.

20. The sensor controller of claim 14, wherein the specific drive operation is an operation related to a receiving process for receiving a detection signal for the passive pointer from the sensor electrodes, the drive parameters include the number or usage rate of the sensor electrodes used in the receiving process, and the drive change unit sets a relatively large number or usage rate for the first electrode group as the first drive parameter, and sets a relatively small number or usage rate for the second electrode group as the second drive parameter.

21. An electronic device comprising: a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar shape; and a sensor controller according to any one of claims 13 to 20, connected to the touch sensor.

22. A position detection method using a sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged in a planar shape, wherein the sensor controller executes an execution step of repeatedly executing a touch scan including a specific drive operation via the plurality of sensor electrodes, the touch scan being a scan for detecting a passive pointer that does not transmit a signal, and a modification step of modifying drive parameters related to the specific drive operation so that the specific drive operation is executed less frequently or the amount of the specific drive operation is reduced while the passive pointer is not detected by the touch scan, compared to when the passive pointer is detected.

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