Electronic pen and pressure output method

Abstract

An electronic pen and a writing pressure output method are provided that can suppress unwanted ink rendering in a manner that is not affected by the specifications of an electronic device that performs ink rendering. [Solution] The control circuit 50 of the electronic pen 12 receives as input the detection value indicated by the detection signal correlated to the amount of writing pressure acting on the pen tip, and outputs a conversion value indicating the magnitude of the amount of writing pressure on a conversion characteristic curve 64, which adjusts the rising sensitivity at which the amount of writing pressure transitions from zero to non-zero upon detection of a predetermined event.

Description

[Technical Field]

[0001] The present invention relates to an electronic pen and a writing pressure output method. [Background technology]

[0002] Conventionally, input systems consisting of an electronic pen (or stylus) as a position indicator and an electronic device equipped with a touch sensor have been known. In these systems, a pressure sensor attached to the tip of the electronic pen detects the amount of pressure applied to the tip, and ink rendering that reproduces an analog-like writing feel is performed using this pressure.

[0003] For example, a pressure sensor may detect a positive amount of pressure even when the electronic pen is in a hover state due to malfunction, friction, wear of the pressure sensor, etc. Therefore, various methods have been proposed to prevent unwanted ink rendering even when a pressure amount that is inconsistent with the hover state is detected.

[0004] Patent document 1 discloses an electronic pen that receives a transmission signal from a touch device from a first antenna and a second antenna, determines the distance from the touch device from the received signal, and transmits a command signal to the touch device to perform ink rendering according to the distance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 1,163,396 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method disclosed in Patent Document 1, the electronic pen itself sequentially determines the distance and judges whether execution is possible, so it may be necessary to implement different judgment processes depending on the software or hardware specifications of the electronic device.

[0007] The present invention has been made in consideration of such problems, and its purpose is to provide an electronic pen and a pen pressure output method that can suppress unwanted ink rendering in a manner that is not affected by the specifications of the electronic device that performs the ink rendering. [Means for solving the problem]

[0008] An electronic pen in a first aspect of the present invention is an electronic pen that indicates a position on a surface sensor by communicating with an electronic device having the surface sensor, and is equipped with a pen pressure sensor that outputs a detection signal correlated to the amount of pen pressure acting on the pen tip, and a control circuit connected to the pen pressure sensor that takes as input the detection value indicated by the detection signal output from the pen pressure sensor and outputs a conversion value indicating the magnitude of the pen pressure amount, and adjusts the rising sensitivity at which the pen pressure amount transitions from zero to non-zero upon detection of a predetermined event on a conversion characteristic curve.

[0009] A second aspect of the pen pressure output method of the present invention is a method relating to an electronic pen that indicates a position on a surface sensor by communicating with an electronic device having the surface sensor, in which the electronic pen acquires a detection signal that correlates with the amount of pen pressure acting on the pen tip, and adjusts the rise sensitivity at which the amount of pen pressure transitions from zero to non-zero on a conversion characteristic curve that uses the detection value indicated by the acquired detection signal as input and a conversion value indicating the magnitude of the amount of pen pressure as output, triggered by the detection of a predetermined event.

[0010] An electronic pen in a third aspect of the present invention is an electronic pen that indicates a position on a surface sensor by communicating with an electronic device having the surface sensor, and comprises a pen pressure sensor that sequentially outputs a detection signal that correlates to the amount of pen pressure acting on the pen tip, and a control circuit connected to the pen pressure sensor.The control circuit comprises a signal processing unit that performs signal processing on a time series of signal values ​​indicated by the detection signal and acquires a detection value that is the signal value in which the signal waveform or frequency characteristics of the time series of signal values ​​have changed, and a processing update unit that sequentially updates signal processing information regarding the presence or absence of the signal processing or calculation depending on the magnitude or amount of change over time of the signal value.

[0011] A pen pressure output method in a fourth aspect of the present invention is a method related to an electronic pen that indicates a position on a surface sensor by communicating with an electronic device having the surface sensor, in which the electronic pen sequentially acquires detection signals that correlate with the amount of pen pressure acting on the pen tip, performs signal processing on a time series of signal values ​​indicated by the detection signals, acquires detection values ​​that are the signal values ​​whose signal waveform or frequency characteristics have changed in the time series of signal values, and sequentially updates signal processing information regarding the presence or absence of the signal processing or calculation depending on the magnitude or amount of change over time of the signal value. [Effects of the Invention]

[0012] According to the present invention, unwanted ink rendering can be suppressed in a manner that is not affected by the specifications of the electronic device that performs the ink rendering. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating the overall configuration of an input system incorporating an electronic pen according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically illustrating the internal structure of the electronic pen of FIG. [Figure 3] FIG. 3 is an electrical block diagram of the electronic pen shown in FIGS. 1 and 2. [Figure 4] FIG. 4 is a functional block diagram relating to a first operation of the control circuit shown in FIG. 3. [Figure 5]10A and 10B are diagrams illustrating an example of a correspondence relationship between a detection value, a conversion value, and a writing pressure amount. [Figure 6] FIG. 6 is a diagram showing a conversion characteristic curve in the correspondence relationship of FIG. 5. [Figure 7] 5 is a flowchart showing an example of an update operation of the conversion characteristic curve by the control circuit of FIGS. 3 and 4. [Figure 8] FIG. 10 is a diagram illustrating an example of a method for setting the number of samples when reception is possible. [Figure 9] FIG. 10 is a diagram illustrating an example of a method for determining a conversion characteristic curve. [Figure 10] FIG. 10 is a diagram illustrating an example of a method for adjusting pen pressure sensitivity. [Figure 11] FIG. 4 is a functional block diagram relating to a second operation of the control circuit shown in FIG. 3. [Figure 12] 12 is a flowchart showing an example of a signal value smoothing operation performed by the control circuit of FIGS. 3 and 11. [Figure 13] FIG. 10 is a diagram illustrating an example of a method for determining an activation multiplier. [Figure 14] FIG. 10 is a diagram illustrating the effect of adaptive filtering. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in each drawing will be denoted by the same reference numerals as much as possible, and duplicate explanations will be omitted. Furthermore, the term "part" may be replaced with other terms such as unit, module, device, or element.

[0015] [Configuration of Electronic Pen 12] <Overall configuration of input system 10> 1 is a diagram showing the overall configuration of an input system 10 incorporating an electronic pen 12 according to one embodiment of the present invention. This input system 10 is configured to be able to provide a "digital ink service" that handles handwritten content by a user as digital data. Specifically, this input system 10 includes an electronic pen 12 and an electronic device 14 that is used together with this electronic pen 12.

[0016] The electronic pen 12 is a pen-type pointing device configured to be capable of one-way or two-way communication with the electronic device 14. In this embodiment, the electronic pen 12 is an active electrostatic coupling (AES) stylus. The electronic pen 12 and the electronic device 14 are capacitively coupled to each other via a capacitance Cpen.

[0017] The electronic device 14 is a computer owned by a user, and is configured, for example, as a tablet, smartphone, or personal computer. Specifically, the electronic device 14 includes a host processor, memory, a communication module, or a display panel (none of which are shown) in addition to the area sensor 16 and the sensor controller 18. The host processor uses the position data sequentially output from the sensor controller 18 to perform processes such as generating digital ink and displaying a pointer.

[0018] The planar sensor 16 is, for example, a capacitance-type touch sensor having a plurality of sensor electrodes arranged in a planar shape. The planar sensor 16 includes, for example, a plurality of X-line electrodes for detecting the position of the X axis of a sensor coordinate system and a plurality of Y-line electrodes for detecting the position of the Y axis. Each line electrode may be made of a transparent conductive material including ITO (Indium Tin Oxide), or may be made of a wire mesh sensor. Note that the planar sensor 16 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.

[0019] The sensor controller 18 is connected to the area sensor 16 and is a control circuit for controlling communication with the electronic pen 12 via the area sensor 16. Specifically, the sensor controller 18 transmits an uplink signal US to the electronic pen 12 and receives a downlink signal DS from the electronic pen 12 to detect the position pointed to by the electronic pen 12.

[0020] <Configuration of the electronic pen 12> Fig. 2 is a diagram showing a schematic internal structure of the electronic pen 12 of Fig. 1. The electronic pen 12 includes a core 20, a tip electrode 22, a ring electrode 24, a writing pressure sensor 26, a circuit board 28, a battery 30, and a housing 32.

[0021] The lead 20 is a rod-shaped member arranged along the pen shaft of the electronic pen 12. The tip electrode 22 and the ring electrode 24 are each made of or contain a conductive material such as metal. Specifically, the tip electrode 22 is a cone-shaped electrode attached to the tip of the lead 20. The ring electrode 24 is a tapered annular electrode whose diameter gradually decreases toward the tip.

[0022] The writing pressure sensor 26 is physically connected to the lead 20 and is configured to be able to detect the amount of writing pressure acting on the tip side (i.e., the pen tip) of the lead 20. The writing pressure sensor 26 may use, for example, a capacitance method, a resistive film method, a piezoelectric element method, an optical method, or a MEMS (Micro Electro-Mechanical System) method as its detection method.

[0023] The circuit board 28 is a board that forms an electric circuit for operating the electronic pen 12. The battery 30 is a power source that supplies driving power to the electronic components or electronic elements provided on the circuit board 28. The housing 32 is configured to be able to accommodate each of the above-mentioned components.

[0024] Figure 3 is an electrical block diagram of the electronic pen 12 shown in Figures 1 and 2. In addition to the tip electrode 22 and writing pressure sensor 26 (Figure 2), the electronic pen 12 includes a power supply circuit 40, a DC (Direct Current) / DC converter 42, a transmitting circuit 44, a receiving circuit 46, a switch 48, and control circuits 50 and 80. For ease of explanation, the configuration and electrical connection relationship of the ring electrode 24 are not shown.

[0025] The power supply circuit 40 generates a drive voltage for the electronic pen 12 and outputs the resulting DC voltage to the DC / DC converter 42. Specifically, the power supply circuit 40 is composed of the above-mentioned battery 30 (FIG. 2) and a power management IC (hereinafter referred to as PMIC 41) that manages the power of the battery 30.

[0026] The DC / DC converter 42 converts the DC voltage input from the power supply circuit 40 into a DC voltage suitable for each circuit, and then outputs the DC current to the transmission circuit 44 and the control circuit 50, respectively.

[0027] The transmitting circuit 44 is a circuit that generates a downlink signal DS and then outputs the downlink signal DS to the switch 48 and the tip electrode 22. Specifically, the transmitting circuit 44 includes an oscillator circuit that generates a carrier signal that oscillates at a predetermined frequency, and a modulator circuit that modulates the carrier signal using data included in a control signal from the control circuit 50.

[0028] The receiving circuit 46 is a circuit that receives the uplink signal US via the tip electrode 22 and the switch 48, and then outputs the signal to the control circuit 50. Specifically, the receiving circuit 46 is configured to include an analog circuit including an amplifier circuit and an AD conversion circuit, and a digital circuit including a matched filter and a data restoration unit.

[0029] Switch 48 is provided such that an input terminal is connected to tip electrode 22, a first output terminal is connected to transmitter circuit 44, and a second output terminal is connected to receiver circuit 46. Switch 48 selectively connects tip electrode 22 to transmitter circuit 44 or receiver circuit 46.

[0030] The control circuits 50, 80 are microcomputers that control the operation of transmitting the downlink signal DS and receiving the uplink signal US. Through control of each component, the control circuits 50, 80 input the uplink signal US from the receiving circuit 46 and the detection signal from the pen pressure sensor 26, and output the downlink signal DS to the transmitting circuit 44 and a control signal to the switch 48.

[0031] [First Operation of Electronic Pen 12] The electronic pen 12 in this embodiment is configured as described above. Next, a first operation of the electronic pen 12 (more specifically, an operation relating to pen pressure adjustment) will be described with reference to FIGS.

[0032] <Functional block diagram of control circuit 50> Fig. 4 is a functional block diagram relating to a first operation of the control circuit 50 shown in Fig. 3. The control circuit 50 functions as a detected value acquisition unit 52, a value conversion unit 54, an event detection unit 56, and a characteristic update unit 58.

[0033] The detection value acquisition unit 52 processes the detection signal output from the pen pressure sensor 26 (FIGS. 2 and 3) to acquire a detection value correlated to the amount of pen pressure. The number of quantization bits for the detection value is determined by the specifications of the ADC (Analog-to-Digital Converter). This detection value is supplied to the value conversion unit 54, event detection unit 56, and characteristic update unit 58, respectively.

[0034] The value conversion unit 54 converts the detection value acquired by the detection value acquisition unit 52 into a conversion value indicating the magnitude of the pen pressure in accordance with a conversion rule. This conversion rule is described by conversion data TD set in the value conversion unit 54, and more specifically, is expressed by a function on a coordinate system in which the first axis represents the detection value and the second axis represents the conversion value (hereinafter also referred to as a "conversion characteristic curve"). Here, the conversion characteristic curve 64 (FIG. 6) is a continuous function consisting of one or more straight lines, one or more curves, or a combination of these.

[0035] The value conversion unit 54 performs conversion processing in accordance with new conversion rules described by the conversion data TD every time the conversion data TD is updated through the characteristic update unit 58. The arithmetic processing that realizes this conversion processing includes function operations, look-up table (LUT) operations, clipping operations, bit shift operations, offset adjustments, gain adjustments, or combinations of these.

[0036] The detected value and the converted value are defined such that the amount of pen pressure increases as the value increases. In particular, when the converted value is defined such that the amount of pen pressure increases linearly as the value increases, the correlation with the actual amount of pen pressure increases, allowing the electronic device 14 to perform ink rendering that is closer to an analog-like experience.

[0037] The event detection unit 56 analyzes information relating to the occurrence of an event (hereinafter referred to as event information), detects a predetermined event, and supplies the type of the detected event to the characteristic update unit 58. Examples of the event information include the reception result of the uplink signal US, identification information of the operating mode currently being executed, the power supply state, the history of detection of the amount of pen pressure, or the contents of data received from the electronic device 14. The attributes of the event are classified, for example, into a "time event" which indicates that there is sufficient time until the amount of pen pressure is detected, and an "abnormal event" which indicates an abnormality in the detection result of the amount of pen pressure.

[0038] A time event is, for example, the electronic pen 12 performing an action that is unlikely to result in an immediate pen-down operation from the time of execution. Examples of time events include the electronic pen 12 [1] failing to receive from the electronic device 14 a predetermined number of times or for a predetermined length of time (first event), [2] transitioning from an operating mode with relatively high power consumption to an operating mode with relatively low power consumption (second event), or [3] transitioning from a power-off state to a power-on state (third event).

[0039] Examples of the second event include [1] a transition from a normal mode to a power-saving mode (or a sleep mode), or [2] a transition from a power-saving mode with relatively high power consumption to a power-saving mode with relatively low power consumption. The "power-saving mode" is an operating mode in which, compared to the normal mode, the frequency of execution of a specific drive operation related to at least one of the signal transmission / reception function or another auxiliary function is relatively low, or the amount of execution of the specific drive operation is relatively small.

[0040] Examples of "specific drive operations" in the transmission function include boosting, frequency hopping, and clock generation. In the reception function, "low frequency of execution of reception operations" includes not only a low number of receptions per unit time, but also zero receptions due to the disabling of reception. Examples of "auxiliary functions" include [1] a communication function that communicates using a method other than the AES method, [2] a pen pressure detection function that detects the amount of pen pressure, [3] an operation detection function that detects the operation state of a switch on the electronic pen 12, [4] a vibration function that vibrates the electronic pen 12, or [5] a write function that writes data supplied from the electronic device 14 to memory.

[0041] The abnormal event may be detected by the electronic pen 12 or by the electronic device 14. When the abnormal event is detected by the electronic device 14, the electronic device 14 transmits to the electronic pen 12 a notification signal notifying the occurrence of the abnormal event or a request signal requesting adjustment of the amount of writing pressure. Examples of the abnormal event include [1] the electronic device 14 being unable to acquire the amount of writing pressure of the electronic pen 12 (hereinafter referred to as a fourth event), or [2] the amount of writing pressure not transitioning from non-zero to zero within a predetermined time from the point in time when a trailing edge is detected (hereinafter referred to as a fifth event).

[0042] The fifth event is detected, for example, by threshold processing using a two-stage threshold. This threshold processing is composed of: [1] a first determination process that determines whether the amount of writing pressure has fallen below a first threshold after a pen-down operation; and [2] a second determination process that determines whether the amount of writing pressure has fallen further below a second threshold (near zero) after the first determination process. This threshold processing is also composed of: [1] a first determination process that determines whether the amount of change (decrease) in the amount of writing pressure over time has exceeded the first threshold after a pen-down operation; and [2] a second determination process that determines whether the amount of writing pressure has fallen below the second threshold (near zero) after the first determination process. This makes it possible to detect a delay in restoration when the pen tip returns to its original state following a pen-up operation.

[0043] Upon detection of a predetermined event, the characteristic update unit 58 updates the conversion characteristic curve 64 (FIG. 6) used in the conversion process performed by the value conversion unit 54. Specifically, the characteristic update unit 58 generates conversion data TD describing the conversion characteristic curve 64 in accordance with the type of event supplied from the event detection unit 56, and supplies the conversion data TD to the value conversion unit 54. The data format of this conversion data TD is determined according to the type of operation used in the conversion process.

[0044] The characteristic update unit 58 adjusts the shape of the conversion characteristic curve 64 ( FIG. 6 ) specified by the conversion rule, for example, the rising sensitivity at which the pen pressure amount transitions from zero to a non-zero value. The characteristic update unit 58 may adjust the rising sensitivity by moving the position of the point at which the pen pressure amount transitions from zero to a non-zero value (hereinafter, the inflection point) along the first axis (i.e., the axis related to the detection value). In this case, the rising sensitivity is increased by moving the position of the inflection point closer to the origin, while the rising sensitivity is decreased by moving the position of the inflection point away from the origin. The characteristic update unit 58 may also adjust the rising sensitivity by changing the slope at the inflection point. In this case, the rising sensitivity is increased by increasing the slope at the inflection point, while the rising sensitivity is decreased by decreasing the slope at the inflection point.

[0045] The characteristic update unit 58 may acquire multiple sample values ​​from a set of detection values ​​acquired by the detection value acquisition unit 52 before or after detecting an event, and adjust the rising edge sensitivity based on statistics regarding the multiple sample values. The number of samples may be any number of statistically significant data. Examples of statistics include the average, maximum, minimum, mode, and median.

[0046] Depending on the type of event, the characteristic update unit 58 may acquire multiple sample values ​​by selecting either a set of detection values ​​obtained after the event is detected or a set of detection values ​​obtained before the event is detected. Specifically, the characteristic update unit 58 may select the "post-detection" detection value under a situation where it is estimated that there is ample time until the pen-down operation is performed, and may select the "pre-detection" detection value under a situation where it is estimated that there is not enough time until the pen-down operation is performed. Examples of events with "much time" include the first to third events described above. Examples of events with "much time" include the fourth and fifth events described above.

[0047] When selecting a detection value set acquired after detecting an event, the characteristic update unit 58 may change the number of samples depending on the type of event. Specifically, the characteristic update unit 58 may increase the number of samples under circumstances where it is estimated that there is ample time before a pen-down operation is performed, and decrease the number of samples under circumstances where it is estimated that there is not enough time before a pen-down operation is performed. Examples of events with "much time" include the first to third events described above. Examples of events with "much time" include the fourth and fifth events described above. Note that when the command signal from the electronic device 14 includes the number of samples, the characteristic update unit 58 may apply the number of samples specified by the electronic device 14.

[0048] <Explanation of conversion characteristic curve 64> FIG. 5 is a diagram showing an example of the correspondence between detected values, converted values, and amounts of writing pressure. The first axis extending to the left of the graph indicates 12-bit detected values ​​(0 to 4095). The second axis extending upward of the graph indicates amounts of writing pressure (units: arbitrary, for example, gf). The third axis extending to the right of the graph indicates 10-bit converted values ​​(0 to 1023). Note that the number of quantization bits for detected values ​​or converted values ​​is not limited to the example shown in FIG. 5.

[0049] The first characteristic curve 60 is a curve relating to the first axis (detection value) and the second axis (amount of writing pressure). In the example of Fig. 5, the first characteristic curve 60 [1] passes through the origin (0,0) and [2] shows a relationship in which the amount of writing pressure increases approximately linearly with respect to the detection value.

[0050] The second characteristic curve 62 is a curve relating to the second axis (amount of writing pressure) and the third axis (conversion value). In the example shown in this figure, the second characteristic curve 62 shows the following relationships: [1] When the amount of writing pressure is P1 or less, the conversion value is constant (minimum value = 0); [2] When the amount of writing pressure exceeds P1, the conversion value increases linearly; and [3] When the amount of writing pressure is P2 or more, the conversion value is constant (maximum value = 1023). Here, the amount of writing pressure P1 corresponds to the detected value D1. Furthermore, the amount of writing pressure P2 corresponds to the detected value D2 and the maximum conversion value (1023), respectively. Furthermore, the amount of writing pressure P3 corresponds to the maximum detection value (4095) and the maximum conversion value (1023), respectively.

[0051] Figure 6 is a diagram showing a conversion characteristic curve 64 in the correspondence relationship of Figure 5. More specifically, conversion characteristic curve 64 corresponds to a curve obtained by combining first characteristic curve 60 and second characteristic curve 62 of Figure 5. The horizontal axis of the graph represents the 12-bit detection value, and the vertical axis of the graph represents the 10-bit conversion value. Conversion characteristic curve 64 shows the following relationship: [1] when the detection value is equal to or less than D1, the conversion value is the minimum value (0); [2] when the detection value exceeds D1, the conversion value increases linearly; and [3] when the detection value is equal to or greater than D2, the conversion value is the maximum value (1023).

[0052] Here, the inflection point Q1 (D1,0) corresponds to the starting point of the rise in the conversion characteristic curve 64. The inflection point Q2 (D2,0) corresponds to the starting point of saturation in the conversion characteristic curve 64. Hereinafter, the range with the inflection point Q1 as the lower limit and the inflection point Q2 as the upper limit will also be referred to as the "effective range."

[0053] <Updating of conversion characteristic curve 64> Next, an example of an operation of updating the conversion characteristic curve 64 by the control circuit 50 of Figures 3 and 4 will be described with reference to the flowchart of Figure 7 and Figure 8. The flowchart of Figure 7 is executed synchronously or asynchronously with the conversion process by the value conversion unit 54 (Figure 4).

[0054] 7, the event detection unit 56 checks whether the timing to update the conversion characteristic curve 64 (hereinafter referred to as the update timing) has arrived. If the update timing has not yet arrived (step SP10: NO), the event detection unit 56 remains in step SP10 until the update timing arrives. On the other hand, if the update timing has arrived (step SP10: YES), the event detection unit 56 proceeds to the next step SP12.

[0055] In step SP12, the event detection unit 56 uses information about the operation of the electronic pen 12 (that is, operation information) to detect a predetermined event (for example, the first to fifth events described above).

[0056] In step SP14, the event detection unit 56 checks whether or not an event was detected in step SP12. If an event was not detected (step SP14: NO), the event detection unit 56 returns to step SP10 and repeats steps SP10 and SP12. On the other hand, if an event was detected (step SP14: YES), the event detection unit 56 supplies the type of the detected event to the characteristic update unit 58, and then proceeds to the next step SP16.

[0057] In step SP16, the characteristic update unit 58 checks whether the electronic pen 12 is currently in a state where it can receive the uplink signal US. If it is in a state where it can receive the uplink signal US (step SP16: YES), the characteristic update unit 58 proceeds to step SP18, and if it is not in a state where it cannot receive the uplink signal US (step SP16: NO), the characteristic update unit 58 proceeds to step SP20.

[0058] In step SP18, the characteristic update unit 58 acquires a plurality of sample values ​​through reception of the uplink signal US after the event is detected, and then proceeds to step SP22.

[0059] FIG. 8 is a diagram showing an example of a method for setting the number of samples when reception is possible. More specifically, FIG. 8 shows the correspondence between the type of event and the number of samples. "High" is set for "Signal Timeout" (Event 1) and "Mode Transition" (Event 2). "Medium" is set for "Power On" (Event 3). "High" is set for "Restore Delay" (Event 4). "Command Value" is set for "External Request" (Event 5).

[0060] In step SP20 of FIG. 7, the characteristic update unit 58 acquires a plurality of sample values ​​from the most recent reception history before the event is detected, and then proceeds to step SP22.

[0061] In step SP22, the characteristic update unit 58 determines the conversion characteristic curve 64 at the current update timing using the multiple sample values ​​acquired in steps SP18 and SP20. Specifically, the characteristic update unit 58 calculates statistics for the multiple sample values, determines the current conversion characteristic curve 64 based on these statistics, and generates conversion data TD for specifying this conversion characteristic curve 64.

[0062] Fig. 9 is a diagram showing an example of a method for determining a conversion characteristic curve 64. The graph in this figure corresponds to the coordinates of the inflection point Q1 in Fig. 6, in other words, to a determination function 66 for determining the lower limit value (detection value D1) of the effective range. The horizontal axis of the graph represents the reception strength Sr, and the vertical axis of the graph represents the lower limit value (D1).

[0063] In the example shown in this figure, the decision function 66 is a linear function connecting two points R1 and R2. The coordinates of R1 are (0, Dmax + Δ), and the coordinates of R2 are (Smax, Dmax). Δ is defined as Dmax - Dmin. Dmax is the maximum value of the N sample values ​​obtained at the start of the current communication session. Dmin is the minimum value of the N sample values ​​obtained at the current update timing. Smax is the maximum value of the reception intensity Sr obtained when the electronic pen 12 was in contact in the past reception history.

[0064] 7, the value conversion unit 54 sets the conversion characteristic curve 64 determined in step SP22. Specifically, the value conversion unit 54 acquires the conversion data TD generated by the characteristic update unit 58 and sets this conversion data TD in a usable state. This adjusts the rise sensitivity of the conversion characteristic curve 64. Thereafter, the control circuit 50 returns to step SP10 and sequentially repeats steps SP10 to SP24, thereby adjusting the pen pressure sensitivity of the pen pressure sensor 26 as appropriate.

[0065] 10 is a diagram showing an example of a method for adjusting pen pressure sensitivity. The horizontal axis of the graph represents the detected value, and the vertical axis of the graph represents the converted value. By adjusting the offset amount of conversion characteristic curve 64 according to the reception strength (or height position) of electronic pen 12, the effective range moves parallel to the horizontal axis while the width of the effective range is kept constant.

[0066] For example, as the electronic pen 12 moves away from the electronic device 14, the effective range of the conversion characteristic curve 64 moves parallel to the right (away from the origin), thereby reducing the sensitivity to the rise of the pen pressure amount. This makes it possible to prevent the occurrence of a phenomenon in which the electronic pen 12 draws despite being in a hover state (so-called ink leakage).

[0067] Conversely, as the electronic pen 12 approaches the electronic device 14, the effective range of the conversion characteristic curve 64 moves in parallel to the left (toward the origin), thereby increasing the sensitivity to the rise of the amount of writing pressure. This improves the responsiveness of drawing with the electronic pen 12.

[0068] <Summary of the first movement> As described above, the input system 10 in this embodiment includes an electronic device 14 having a planar sensor 16, and an electronic pen 12 that indicates a position on the planar sensor 16 through communication with the electronic device 14. The electronic pen 12 includes a writing pressure sensor 26 that outputs a detection signal that correlates with the amount of writing pressure acting on the pen tip, and a control circuit 50 connected to the writing pressure sensor 26. The control circuit 50 includes a value conversion unit 54 that receives as input a detection value indicated by the detection signal output from the writing pressure sensor 26 and outputs a conversion value that indicates the magnitude of the writing pressure, and that adjusts the rising sensitivity at which the writing pressure amount transitions from zero to non-zero upon detection of a predetermined event on a conversion characteristic curve 64.

[0069] According to the pen pressure output method of this embodiment, the control circuit 50 of the electronic pen 12 acquires a detection signal that correlates with the amount of pen pressure acting on the pen tip, and adjusts the rising sensitivity at which the amount of pen pressure transitions from zero to non-zero on a conversion characteristic curve 64 that takes the detection value indicated by the detection signal as input and outputs a conversion value indicating the magnitude of the amount of pen pressure, triggered by the detection of a predetermined event.

[0070] In this way, by adjusting the rise sensitivity in response to the detection of a predetermined event, unwanted ink rendering can be suppressed in a manner that is not affected by the specifications of the electronic device 14 that performs the ink rendering.

[0071] The event may also be the electronic pen 12 performing an operation that is unlikely to result in an immediate pen-down operation from the time of execution. For example, the event may be the electronic pen 12 [1] failing to receive data from the electronic device 14 a predetermined number of times or for a predetermined length of time, [2] transitioning from an operating mode with relatively high power consumption to an operating mode with relatively low power consumption, or [3] transitioning from a power-off state to a power-on state. This allows the rise sensitivity to be adjusted at a timing when there is sufficient time before the pen-down operation is performed.

[0072] The event may also be the failure of the pen pressure amount to transition from non-zero to zero within a predetermined time from the detection of the falling edge. This allows the desired pen pressure to be detected by adjusting the rising edge sensitivity even when the pen tip does not fully return to its original position following a pen-up operation.

[0073] The event may also be the reception by the electronic pen 12 of a notification signal notifying that an abnormality in the detection result of the amount of writing pressure has been detected, or a request signal requesting adjustment of the rising sensitivity from the electronic device 14. In this way, the rising sensitivity can be adjusted in response to the notification or request from the electronic device 14.

[0074] The value converter 54 may also obtain multiple sample values ​​from a set of detection values ​​and change the adjustment amount of the rising edge sensitivity based on statistics regarding the multiple sample values, thereby making adjustments that take into account statistical variations in the detection values.

[0075] Furthermore, the value converter 54 may acquire multiple sample values ​​by selecting either the detection values ​​obtained before the event is detected or the detection values ​​obtained after the event is detected, depending on the type of event. This allows the value converter 54 to select whether or not sampling of the detection values ​​is necessary after the event is detected, depending on the type of event.

[0076] Furthermore, when using multiple sample values ​​acquired after an event is detected, the value converter 54 may change the number of samples depending on the type of event, thereby changing the time required for sampling the detected values ​​depending on the type of event.

[0077] [Second Operation of Electronic Pen 12] Next, the second operation of electronic pen 12 (more specifically, the operation related to smoothing of signal values) will be described with reference to FIGS.

[0078] <Functional block diagram of control circuit 80> Fig. 11 is a functional block diagram relating to the second operation of the control circuit 80 shown in Fig. 3. The control circuit 80 functions as a detection value calculation section 82 and a value conversion section 84.

[0079] The detection value calculation unit 82 calculates a signal value (i.e., a detection value) with a modified signal waveform or frequency characteristic, using a time series of signal values ​​indicated by the detection signal from the pen pressure sensor 26 (FIGS. 2 and 3). Specifically, the detection value calculation unit 82 includes a signal value acquisition unit 86, a signal value holding unit 88, a filter processing unit 90 (corresponding to the "signal processing unit"), and a filter update unit 92 (corresponding to the "processing update unit").

[0080] 4, the signal value acquisition unit 86 processes the detection signals sequentially output from the pen pressure sensor 26 and acquires signal values ​​correlating with the amount of pen pressure. The number of quantization bits of the signal values ​​is determined by the specifications of the ADC. These signal values ​​are sequentially supplied to a signal value holding unit 88.

[0081] The signal value holding unit 88 temporarily holds the time series of signal values ​​acquired by the signal value acquisition unit 86 as a signal value set SVs. The signal value set SVs is held, for example, in a FIFO (First-In First-Out) format. The length of the buffer is selected to be any integer value equal to or greater than 2.

[0082] The filter processing unit 90 performs signal processing on the signal value set SVs held by the signal value holding unit 88, and acquires signal values ​​(i.e., detection values) in which the signal waveform or frequency characteristics of the signal value set SVs have been changed. Examples of "changing the signal waveform" include: [1] increasing (or decreasing) the signal values ​​overall while maintaining the similarity of the signal waveform; [2] relatively increasing (or decreasing) a signal value that constitutes a portion of the original signal waveform; [3] sharpening the edge portions of the signal waveform; or [4] dulling the edge portions of the signal waveform. Examples of "changing the frequency characteristics" include: [1] a "smoothing filter" that lowers the frequency characteristics overall; [2] a "low-pass filter" that mainly passes low frequencies; [3] a "high-pass filter" that mainly passes high frequencies; or [4] a "band-pass filter" that passes only a specific frequency band.

[0083] The above-mentioned signal processing is specified by information regarding the presence or absence of processing or calculation (hereinafter referred to as signal processing information). For example, if the signal processing is "filter processing", this signal processing information includes filter information FI regarding the presence or absence of filter processing or calculation.

[0084] In this embodiment, the filter processing unit 90 performs filter processing on the signal value set SVs to obtain signal values ​​(i.e., detection values) whose frequency characteristics are modulated. This "modulation of frequency characteristics" is intended to "smooth" the detection signal to remove noise components. The frequency characteristics are specified by filter information FI set in the filter processing unit 90. Every time the filter information FI is updated by the filter update unit 92, the filter processing unit 90 performs filter processing in accordance with the filter information FI.

[0085] The filter information FI is information about whether or not a filter process is performed or about a calculation. The filter information FI is, for example, a tap coefficient in an FIR (Finite Impulse Response) filter. The number of taps in an FIR filter is an integer equal to or greater than two, and may be a fixed value or a variable value.

[0086] When the signal value at time t is Sp(t), the sampling interval is Δt, and the number of taps is 2, the detected value D(t) at time t is calculated according to the following equation (1). D(t)=γ Sp(t)+(1-γ) Sp(t-Δt) (1)

[0087] The tap coefficient γ is one aspect of the filter information FI and is a variable parameter that can take a range of [0, 1]. As can be seen from the above equation (1), γ=1 corresponds to "filter OFF" (or equivalent transformation). As the value of γ decreases, the frequency characteristics decrease or the filter smoothness increases.

[0088] The filter update unit 92 determines whether or not to perform signal processing (here, filter processing) and updates filter information FI to be used for filter processing, depending on the magnitude or time change of the signal values ​​constituting the signal value set SVs. The "signal value magnitude" refers to the magnitude of one or more signal values ​​constituting the value set {Sp(t-iΔt)} (i = 0, 1, ..., n-1). The "time change of the signal value" refers to one or more time change amounts constituting the value set {ΔSp(i,j)} (i,j = 0, 1, ..., n-1). Note that Δt is the sampling interval, and ΔSp(i,j) = |Sp(t-iΔt) - Sp(t-jΔt)|.

[0089] The tap coefficient γ(t) at time t is calculated by, for example, the product of a smoothing coefficient α(t) and an activation multiplier β(t). Here, the smoothing coefficient α(t) corresponds to a coefficient that essentially determines the frequency characteristics of the filter and is a variable parameter that can take on a range of [0, 1]. The activation multiplier β(t) corresponds to a coefficient that specifies whether the filter process is on or off and is a variable parameter that can take on two values: 0 (off) or 1 (on). γ(t)=1+(α(t)-1)β(t) ···(2)

[0090] The smoothing coefficient α(t) is generally expressed as the following equation (3) using an arbitrary function F(·). For example, the smoothing coefficient α(t) can be calculated as equation (4) using an arbitrary function F1(·), or as equation (5) using an arbitrary function F2(·). α(t)=F({Sp(t-iΔt)},{ΔSp(i,j)}) ···(3) α(t)=F1(Sp(t)) (4) α(t)=F2(ΔSp(0,1)) (5)

[0091] The filter update unit 92 determines the filter information FI so that the frequency characteristics become higher as the signal value becomes smaller, or become lower as the signal value becomes larger. In the example of equation (4), the function F1(x) is a function that includes a section where x monotonically decreases or remains constant as x increases (i.e., a monotonically non-increasing function).

[0092] The filter update unit 92 may determine the filter information FI so that the frequency characteristics become lower as the amount of change over time becomes smaller, or the frequency characteristics become higher as the amount of change over time becomes larger. In the example of equation (5), the function F2(x) is a function that monotonically increases or includes a section where it is constant as x increases (or a monotonically non-decreasing function).

[0093] The activation multiplier β(t) is generally expressed as the following equation (6) using an arbitrary function G(·): For example, the activation multiplier β(t) can be obtained as shown in equation (7) using an arbitrary function G1(·). β(t)=G({Sp(t-iΔt)},{ΔSp(i,j)}) ···(6) β(t)=G1(Sp(t)) (7)

[0094] The filter update unit 92 does not perform signal processing (here, filter processing) within a partial interval that includes the detected value D1 (i.e., the inflection point detected value) corresponding to the inflection point Q1 (FIG. 6) on the conversion characteristic curve 64, among all intervals that the signal value can take, but performs signal processing (here, filter processing) outside the partial interval. In the example of the combination of equation (2) and equation (7), β(t)=0 if Sp(t) belongs to the partial interval, and β(t)=1 if Sp(t) does not belong to the partial interval.

[0095] The value converter 84 converts the detection value calculated by the detection value calculator 82 into a conversion value indicating the magnitude of the pen pressure in accordance with a conversion rule. This conversion rule is described by conversion data TD set in the value converter 84. The value converter 84 may be replaced with the value converter 54 shown in FIG. 4.

[0096] <Smoothing of signal values> Next, an example of the signal value smoothing operation by the control circuit 80 of Figures 3 and 11 will be described with reference to the flowchart of Figure 12 and Figures 13 and 14. The flowchart of Figure 12 is executed synchronously or asynchronously with the update process of the conversion characteristic curve 64 (Figure 6).

[0097] 12, the signal value acquiring unit 86 checks whether the timing for detecting the amount of writing pressure of the electronic pen 12 (hereinafter, the detection timing) has arrived. If the detection timing has not yet arrived (step SP30: NO), the signal value acquiring unit 86 remains in step SP30 until the detection timing arrives. On the other hand, if the detection timing has arrived (step SP30: YES), the signal value acquiring unit 86 proceeds to the next step, SP32.

[0098] In step SP32, the signal value acquisition unit 86 performs sampling processing on the detection signal output from the writing pressure sensor 26, and acquires the signal value Sp(t) at the current time t.

[0099] In step SP34, the signal value holding unit 88 temporarily holds the signal value Sp(t) acquired in step SP32. Thereby, the signal value set SVs indicating the value set {Sp(t - iΔt)} is updated.

[0100] In step SP36, the filter update unit 92 determines the filter information FI using the signal value set SVs held in step SP34. Here, the filter update unit 92 calculates the smoothing coefficient α(t) according to Equation (5), the activation multiplier β(t) according to Equation (7), and the tap coefficient γ(t) according to Equation (2), respectively. Thereby, the filter information FI is determined and supplied to the filter processing unit 90.

[0101] FIG. 13 is a diagram showing an example of a method for determining the activation multiplier β. The horizontal axis of the graph indicates the signal value Sp, and the vertical axis of the graph indicates the activation multiplier β. The activation multiplier β(Sp) is specified by two threshold values Th1 and Th2. The threshold values Th1 and Th2 satisfy the magnitude relationship of 0 < Th1 < D1 < Th2. Here, D1 is the detection value corresponding to the inflection point Q1 (FIG. 6) on the conversion characteristic curve 64. The activation multiplier β(Sp) takes the value of "1" in the interval of [1] 0 ≤ Sp < Th1, takes the value of "0" in the interval of [2] Th1 ≤ Sp ≤ Th2, and takes the value of "1" in the interval of [3] Sp > Th2. In the example of FIG. 13, the width of the filter dead zone corresponds to (Th2 - Th1).

[0102] In step SP38 of FIG. 12, the filter processing unit 90 performs filter processing on the signal value set SVs held in step SP34 using the filter information FI updated in step SP36. Thereby, a signal value (that is, a detection value) with modulated frequency characteristics is obtained.

[0103] In step SP40, the value conversion unit converts the detection value obtained through the filtering process in step SP38 into a conversion value indicating the magnitude of the amount of writing pressure. Thereafter, the control circuit 80 returns to step SP30 and sequentially repeats steps SP30 to SP40 to output the amount of writing pressure periodically or irregularly.

[0104] 14 is a diagram showing the effect of adaptive filtering. The horizontal axis of the graph indicates time, and the vertical axis of the graph indicates the detected value. Time series Seq1 to Seq3 each show the behavior of the detected value when touch operations with the electronic pen 12 are repeated. Specifically, the pen tip of the electronic pen 12 is in a "contact state" during four time periods t=T1-T2, t=T3-T4, t=T5-T6, and t=T7-T8.

[0105] The time series Seq1 corresponds to "ideal behavior" and is a collection of ideal values ​​obtained by converting the actual measurement results of the pen pressure amount into detection values. The time series Seq2 corresponds to "comparison example" and is a collection of detection values ​​obtained by applying the same filter processing regardless of changes in the detection values. The time series Seq3 corresponds to "embodiment" and is a collection of detection values ​​obtained by applying adaptive filter processing by the detection value calculation unit 82 in FIG. 11.

[0106] As can be seen from the comparison between the time series Seq1 and Seq2, the time series Seq2 exhibits reduced rising and falling sensitivity, as well as a smaller peak in the detected value. In other words, the filter processing of the "Comparative Example" may result in a situation where the amount of pen pressure cannot be accurately detected due to excessive smoothing. In contrast, as can be seen from the comparison between the time series Seq1 and Seq3, the time series Seq3 exhibits nearly the same behavior as the time series Seq1. In other words, the filter processing of the "Example" allows for more accurate detection of the amount of pen pressure by selecting a filter according to the magnitude or temporal change of the signal value.

[0107] <Summary of the second movement> As described above, the input system 10 in this embodiment includes an electronic device 14 having a planar sensor 16, and an electronic pen 12 that indicates a position on the planar sensor 16 through communication with the electronic device 14. The electronic pen 12 includes a writing pressure sensor 26 that outputs a detection signal that correlates with the amount of writing pressure acting on the pen tip, and a control circuit 80 connected to the writing pressure sensor 26. The control circuit 80 includes a signal processing unit (here, a filter processing unit 90) that performs signal processing on a time series of signal values ​​(here, a signal value set SVs) indicated by the detection signal and acquires detection values ​​that are signal values ​​in which the signal waveform or frequency characteristics of the signal value set SVs have changed, and a processing update unit (here, a filter update unit 92) that sequentially updates signal processing information (here, filter information FI) related to the presence or absence of signal processing or calculation in accordance with the magnitude or amount of change over time of the signal value.

[0108] According to the pen pressure output method of this embodiment, the control circuit 80 possessed by the electronic pen 12 acquires a detection signal that correlates with the amount of pen pressure acting on the pen tip, performs signal processing on the time series of signal values ​​indicated by the detection signal (here, signal value set SVs), acquires a detection value that is a signal value in which the signal waveform or frequency characteristics of the signal value set SVs have changed, and sequentially updates signal processing information (here, filter information FI) regarding whether or not signal processing is performed or the calculation depending on the magnitude or amount of change over time of the signal value.

[0109] By configuring in this manner, it becomes possible to perform signal processing according to the magnitude of the signal value or the amount of change over time, and unwanted ink rendering can be suppressed in a manner that is not affected by the specifications of the electronic device 14 that performs the ink rendering.

[0110] Furthermore, when the signal processing includes a filter process for modulating the frequency characteristics of the signal value set SVs, the signal processing information may include filter information FI relating to the presence or absence of the filter process or the calculation.

[0111] The filter update unit 92 may also determine and update the filter information FI so that the frequency characteristics become lower as the amount of change over time becomes smaller, or the frequency characteristics become higher as the amount of change over time becomes larger. This makes it possible to suppress smoothing for sections of the signal value set SVs where the amount of change over time is large.

[0112] Furthermore, the filter update unit 92 may determine and update the filter information FI so that the frequency characteristics become higher as the signal value becomes smaller. This makes it possible to suppress smoothing for a section of the signal value set SVs where the signal value is small (for example, a section where the writing pressure amount rises).

[0113] Furthermore, the filter update unit 92 may not perform signal processing within a partial interval that includes an inflection point detection value (D1), which is a detection value corresponding to an inflection point, within the entire interval in which the signal value can be taken, but may perform signal processing outside the partial interval. This makes it possible to suppress changes in the signal waveform or frequency characteristics of the signal value set SVs for the rising interval of the writing pressure amount.

[0114] [Variations] The present invention is not limited to the above-described embodiment, and can be freely modified without departing from the spirit and scope of the present invention. Alternatively, the respective configurations may be arbitrarily combined within the scope of no technical contradiction. Alternatively, the execution or execution order of each step constituting the flowchart may be changed within the scope of no technical contradiction.

[0115] In the above embodiment, the electronic pen 12 is an active electrostatic coupling (AES) stylus, but instead, the electronic pen 12 may be an electromagnetic induction (EMR) stylus. In this device configuration, the electronic device 14 is provided with a planar sensor having multiple loop coils formed thereon, and the electronic pen 12 is provided with a receiving circuit that receives a magnetic field signal emitted by the planar sensor.

[0116] In the above embodiment, the electronic pen 12 receives a signal through communication using capacitive coupling with the area sensor 16 of the electronic device 14, and the rise sensitivity is adjusted according to the strength of the received signal. However, the communication method is not limited to this. For example, the strength of the received signal obtained through other wireless communication means such as Bluetooth (registered trademark), BLE (Bluetooth (registered trademark) Low Energy), or UWB (Ultra-Wide Band) may also be used.

[0117] In the above embodiment, the control circuit 80 performs signal processing on the digital signal after sampling, but the calculation method is not limited to digital signal processing. For example, the control circuit 80 may perform various signal processing (specifically, smoothing processing via an analog filter, etc.) on the analog signal before sampling. [Explanation of symbols]

[0118] 10...input system, 12...electronic pen, 14...electronic device, 16...surface sensor, 26...pen pressure sensor, 50, 80...control circuit, 52, 86...detection value acquisition unit, 54, 84...value conversion unit, 56...event detection unit, 58...characteristic update unit, 64...conversion characteristic curve, 82...detection value calculation unit, 88...signal value holding unit, 90...filter processing unit (signal processing unit), 92...filter update unit (processing update unit), FI...filter information (signal processing information), SVs...signal value set (time series of signal values), TD...conversion data

Claims

1. An electronic pen that indicates a position on an area sensor by communicating with an electronic device having the area sensor, a writing pressure sensor that outputs a detection signal that correlates with the amount of writing pressure acting on the pen tip; a control circuit connected to the writing pressure sensor, the control circuit adjusting a rising sensitivity of the writing pressure amount, which transitions from zero to non-zero, when a predetermined event is detected on a conversion characteristic curve that has an input of a detection value indicated by the detection signal output from the writing pressure sensor and an output of a conversion value indicating the magnitude of the writing pressure amount; An electronic pen comprising:

2. The event is The electronic pen, A predetermined number of consecutive failed attempts to receive data from the electronic device or a predetermined length of time; A transition from a relatively high-power operating mode to a relatively low-power operating mode, or A transition from a power-off state to a power-on state occurs. The electronic pen according to claim 1 .

3. The event is that the electronic pen has performed an action that is unlikely to result in an immediate pen-down operation from the time of execution. The electronic pen according to claim 1 .

4. The event is that the amount of writing pressure does not transition from non-zero to zero within a predetermined time from the time when a trailing edge is detected. The electronic pen according to claim 1 .

5. The event is that the electronic pen receives, from the electronic device, a notification signal notifying that an abnormality has been detected in the detection result of the amount of writing pressure, or a request signal requesting adjustment of the rise sensitivity. The electronic pen according to claim 1 .

6. the control circuit acquires a plurality of sample values ​​from the set of detection values, and changes the adjustment amount of the rising edge sensitivity based on statistics regarding the plurality of sample values. The electronic pen according to claim 1 .

7. the control circuit selects, depending on the type of the event, either the detection value obtained before the event is detected or the detection value obtained after the event is detected, and acquires the plurality of sampled values. The electronic pen according to claim 1 .

8. When the control circuit uses the plurality of sampled values ​​acquired after the detection of the event, the control circuit changes the number of samples depending on the type of the event. The electronic pen according to claim 1 .

9. 1. A writing pressure output method for an electronic pen that indicates a position on an area sensor by communication with an electronic device having the area sensor, comprising: The electronic pen is A detection signal correlating with the amount of pressure applied to the pen tip is obtained; A pen pressure output method that adjusts the rising sensitivity of the pen pressure amount, at which the pen pressure amount transitions from zero to non-zero, upon detection of a predetermined event on a conversion characteristic curve that uses the detection value indicated by the acquired detection signal as input and a conversion value indicating the magnitude of the pen pressure amount as output.

10. An electronic pen that indicates a position on an area sensor by communicating with an electronic device having the area sensor, a writing pressure sensor that sequentially outputs a detection signal that correlates with the amount of writing pressure acting on the pen tip; a control circuit connected to the writing pressure sensor; Equipped with The control circuit a signal processing unit that performs signal processing on a time series of signal values ​​indicated by the detection signal, and acquires a detection value that is the signal value in which a signal waveform or frequency characteristic of the time series of signal values ​​has changed; a processing update unit that sequentially updates signal processing information regarding the presence or absence of the signal processing or the calculation in accordance with the magnitude or the amount of change over time of the signal value; An electronic pen comprising:

11. the signal processing includes a filter process for modulating a frequency characteristic of the time series of the signal values; The signal processing information includes filter information regarding whether or not the filtering is performed or an operation of the filtering. The electronic pen according to claim 10.

12. the processing update unit determines and updates the filter information so that the frequency characteristics become lower as the amount of change over time becomes smaller, or so that the frequency characteristics become higher as the amount of change over time becomes larger. The electronic pen according to claim 11.

13. the processing update unit determines and updates the filter information so that the frequency characteristic becomes higher as the signal value becomes smaller. The electronic pen according to claim 11.

14. When a point on a conversion characteristic curve, which has the detection value as an input and a conversion value indicating the magnitude of the writing pressure as an output, where the writing pressure amount transitions from zero to non-zero is defined as an inflection point, the processing update unit determines the signal processing information so that, of all intervals in which the signal value can be, the signal processing is not performed within a partial interval including an inflection point detection value, which is the detection value corresponding to the inflection point, and the signal processing is performed outside the partial interval. The electronic pen according to claim 10.

15. 1. A writing pressure output method for an electronic pen that indicates a position on an area sensor by communication with an electronic device having the area sensor, comprising: The electronic pen is A detection signal that correlates with the amount of writing pressure acting on the pen tip is sequentially acquired, performing signal processing on a time series of signal values ​​indicated by the detection signal, and acquiring detection values ​​which are the signal values ​​in which the signal waveform or frequency characteristics of the time series of signal values ​​have changed; A writing pressure output method, wherein signal processing information regarding the presence or absence of signal processing or calculation is successively updated according to the magnitude or time change amount of the signal value.

Images