System comprising a pen and a sensor controller, pen and sensor controller

Abstract

The present invention relates to a system including a pen and a sensor controller, a pen and a sensor controller that suppress unnaturalness of line width and transparency of a start portion of a stroke due to pairing. The system includes a pen and a sensor controller that are paired by bidirectional communication, the pen periodically transmitting an N-bit pen pressure value to the sensor controller, wherein the pen periodically transmits a pen pressure value (PRD) after completion of processing for pairing, and on the other hand, during a period before completion of the processing for pairing, a shortened pen pressure value (SPRD) composed of a portion of M bits of the higher bits of the pen pressure value (PRD) that is shorter than the N bits is transmitted instead of the pen pressure value (PRD).

Description

Technical Field

[0001] This invention relates to a system comprising a pen and a sensor controller, and the pen and sensor controller thereof. Background Technology

[0002] Systems are known to enable pen input to electronic devices such as tablets through bidirectional communication between the pen and a sensor controller. In such systems, the sensor controller periodically sends uplink signals, and the pen sends downlink signals in response to the uplink signals.

[0003] The uplink signal is used for timing the start of frames used in signal transmission and reception, and for notifying the pen of commands to control the pen. The downlink signal comprises a position signal and a data signal; the position signal is an unmodulated carrier signal, and the data signal is a carrier signal modulated from data such as pen pressure values. The sensor controller, upon receiving the downlink signal, detects the pen's position based on the received strength of the position signals at each of the multiple sensor electrodes disposed within the touch surface, and obtains the data transmitted by the pen by demodulating the data signal. The pen pressure value in this obtained data is used to control the line width or transparency of the strokes drawn based on the detected position.

[0004] When a new pen input begins in the aforementioned system, processing (hereinafter referred to as "pairing") is performed between the pen and the sensor controller to share a pen ID and various communication parameters. Examples of this pairing are disclosed in Patent Documents 1 to 3. In the example of Patent Document 1, pairing is performed by sending constitutive data containing a stylus identifier from the pen to the sensor controller and by sending channel data of a specified frequency and time slot from the sensor controller to the pen. In the example of Patent Document 2, pairing is performed by sending a unique ID from the pen to the sensor controller, which is a 52-bit information that is different for each pen.

[0005] Patent Document 3 describes that communication between the pen and the sensor controller is performed in frames, with the sensor controller sending an uplink signal at the beginning of each frame. In the example of Patent Document 3, pairing is performed by the pen receiving the uplink signal sending an ACK signal within the same frame, and the sensor controller receiving the ACK signal using the uplink signal of the next frame to notify the pen of the temporarily used pen ID (local ID), time slot, and frequency.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2016 / 139861

[0009] Patent Document 2: International Publication No. 2018 / 029855

[0010] Patent Document 3: US Patent No. 9977519 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] When performing the pairing described above, due to the large size of the data that should be shared between the pen and the sensor controller, and the time required until the pen is in a state capable of transmitting pen pressure values, a situation may occur where a position signal is transmitted without accompanying pen pressure values ​​during the pairing process. For example, in the case where the pen needs to transmit a 52-bit intrinsic ID for pairing, as in the example of Patent Document 2, the idle capacity of the data signal is insufficient, and therefore, pen pressure values ​​cannot be transmitted during pairing.

[0013] If a position signal is sent without accompanying pen pressure values, the line width and transparency of the strokes may sometimes appear unnatural at the beginning of the stroke. That is, if the electronic device is configured, for example, not to draw a stroke until the pen pressure value is received, a discrepancy may occur between the original starting position of the stroke and the actual starting position of the drawn stroke. Furthermore, if the electronic device is configured, for example, to compensate for unreceived pen pressure values ​​using subsequently received pen pressure values, it may draw strokes with pen pressure values ​​that are significantly different from the original pen pressure values.

[0014] Therefore, one of the objectives of this invention is to provide a system, pen and sensor controller, that includes a pen and sensor controller capable of suppressing the unnatural line width and transparency of the starting portion of a stroke due to pairing.

[0015] Methods for solving problems

[0016] The system of the present invention includes a pen and a sensor controller for pairing via bidirectional communication. The pen periodically sends an N-bit pen pressure value to the sensor controller. The pen periodically sends the pen pressure value after the pairing process is completed. On the other hand, during the period before the pairing process is completed, a shortened pen pressure value is sent instead of the pen pressure value. The shortened pen pressure value is composed of the high M bits of the pen pressure value that are shorter than the N bits.

[0017] The pen of the present invention pairs with a sensor controller via bidirectional communication and periodically sends an N-bit pen pressure value to the sensor controller. The pen pressure value is sent periodically after the pairing process is completed. On the other hand, during the period before the pairing process is completed, a shortened pen pressure value is sent instead of the pen pressure value. The shortened pen pressure value is composed of the high M bits of the pen pressure value that are shorter than the N bits.

[0018] The sensor controller of the present invention pairs with a pen through bidirectional communication and periodically receives an N-bit pen pressure value from the pen. In the case of receiving a shortened pen pressure value from the pen, which is composed of a portion of the pen pressure value that is shorter than the N bits, the pen pressure value is obtained by supplementing the lower NM bits with a predetermined value.

[0019] Invention Effects

[0020] According to the present invention, even when the pen cannot send an N-bit pen pressure value, it can send a shortened pen pressure value consisting of the high M bits of the pen pressure value, thereby suppressing the unnatural line width and transparency of the starting part of the stroke due to pairing. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating the structure of system 1 according to an embodiment of the present invention.

[0022] Figure 2 This is a diagram showing the internal structure of the pen 2 and the tablet terminal 3.

[0023] Figure 3 This is a diagram illustrating the construction of frames used for transmitting and receiving uplink signal US and downlink signal DS.

[0024] Figure 4 (a) to (c) show the stroke data Sa to Sc when pen input begins in a state that has never been paired.

[0025] Figure 5 This is a flowchart showing the processing performed by the circuit section 23 of the pen 2.

[0026] Figure 6 (a) is shown in Figure 5 A diagram (b) shows the downlink signal DS transmitted by circuit section 23 in step S6. Figure 5 The diagram shows the downlink signal DS sent by the circuit section 23 in step S7.

[0027] Figure 7 (a) is a diagram showing an example of the construction of a pen pressure value PRD, (b) is a diagram showing the construction of a shortened pen pressure value SPRD corresponding to the pen pressure value PRD shown in (a), and (c) is a diagram showing the case where the shortened pen pressure value SPRD is the shortened pen pressure value SPRD shown in (b). Figure 8 The graph of the pen pressure value PRD exported in step S28.

[0028] Figure 8 This is a flowchart illustrating the processing performed by the sensor controller 31.

[0029] Label Explanation

[0030] 1 System

[0031] 2 strokes

[0032] 3. Tablet Terminal

[0033] 3a panel

[0034] 20 cores

[0035] 21. Pen tip electrode

[0036] 22 Pen pressure detection sensors

[0037] 23 Circuit Section

[0038] 24 Power Supply

[0039] 30 sensors

[0040] 30X sensor electrodes

[0041] 30X, 30Y sensor electrodes

[0042] 31 Sensor Controller

[0043] 32 host processors

[0044] DATA signal

[0045] DS downlink signal

[0046] F frame

[0047] Positions P1 to P8

[0048] PAIRD pairing data

[0049] PRD Pen Pressure Value

[0050] PS position signal

[0051] Sa~Sc Stroke Data

[0052] SPRD shortens pen pressure value

[0053] TS slot

[0054] US uplink signal Detailed Implementation

[0055] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0056] Figure 1This is a diagram showing the structure of system 1 according to this embodiment. As shown in the diagram, system 1 is configured to include a pen 2 and a tablet terminal 3.

[0057] Pen 2 is a position indicator for pen input on the tablet terminal 3, used to indicate the position on the panel surface 3a of the tablet terminal 3. The user inputs various graphics and text as shown in the figure by sliding the tip of pen 2 on the panel surface 3a.

[0058] The tablet terminal 3 is a computer with a built-in display device such as a liquid crystal display (LCD) or an organic EL display. It can also replace a laptop or desktop personal computer or a smartphone. The panel 3a of the tablet terminal 3 serves as both the display surface and the touch surface for pen input. The display device functions as described later in the host processor 32 (see reference). Figure 2 The control of the pen 2 enables the visual output of graphics and text input by the user onto the panel surface 3a. In the following description, the horizontal direction of the panel surface 3a as observed by the user will be referred to as the X direction, the depth direction as the Y direction, and the direction orthogonal to the X and Y directions as the Z direction.

[0059] The tablet terminal 3 detects the pen 2 using the pen 2 and the sensor controller 31 described later (see reference). Figure 2 This can be performed through bidirectional communication. Specific examples of such methods include active electrostatic discharge (AED) and electromagnetic induction. The following explanation will assume the use of the active electrostatic discharge method. The tablet terminal 3 can also support finger-based input (touch input), in which case finger detection is performed, for example, using capacitive discharge (VCD).

[0060] Figure 2 This diagram shows the internal structures of both the pen 2 and the tablet terminal 3. However, regarding the internal structure of the tablet terminal 3, only the part related to the position detection of the pen 2 is shown.

[0061] If we first focus on pen 2, then as Figure 2 As shown, the pen 2 is configured to include a core 20, a pen tip electrode 21, a pen pressure detection sensor 22, a circuit section 23, and a power supply 24. The power supply 24 is, for example, a cylindrical AAAA battery.

[0062] The core 20 is a rod-shaped component arranged so that its length direction is aligned with the axis of the pen 2. A conductive material is coated on the surface of the front end of the core 20 to form the pen tip electrode 21. The rear end of the core 20 abuts against the pen pressure detection sensor 22. The pen pressure detection sensor 22 detects the pressure (pen pressure) applied to the front end of the core 20.

[0063] The circuit unit 23 is an integrated circuit that performs various processes described later by reading and executing a program stored in the built-in memory. It is configured to receive an uplink signal US transmitted from the panel surface 3a of the tablet terminal 3 via the pen tip electrode 21 and to transmit a downlink signal DS towards the panel surface 3a of the tablet terminal 3 via the pen tip electrode 21. In addition to the aforementioned program, a pen ID pre-assigned to the pen 2 is also written into the built-in memory of the circuit unit 23.

[0064] If we continue to focus on tablet terminal 3, tablet terminal 3 is configured to have sensor 30, sensor controller 31 and host processor 32.

[0065] Sensor 30 is a touch sensor embedded under the panel surface 3a, configured to include multiple sensor electrodes 30X and 30Y capacitively coupled to the pen tip electrode 21. The multiple sensor electrodes 30X extend in the Y direction and are arranged side-by-side in the X direction with a constant spacing. Similarly, the multiple sensor electrodes 30Y extend in the X direction and are arranged side-by-side in the Y direction with a constant spacing. Figure 2 As shown, multiple sensor electrodes 30X and multiple sensor electrodes 30Y are arranged overlappingly in the Z direction. It should be noted that... Figure 2 In the diagram, sensor electrodes 30X and 30Y are shown using plate-shaped conductors, but in practice, sensor electrodes 30X and 30Y could also be conductors of other shapes, such as mesh conductors.

[0066] The sensor controller 31 is an integrated circuit that performs various processes, described later, by reading and executing a program stored in its built-in memory. It is configured to receive the downlink signal DS transmitted by the pen 2 via the sensor 30 and to transmit an uplink signal US to the pen 2 via the sensor 30. Figure 2 As shown, the sensor controller 31 is connected to each of the plurality of sensor electrodes 30X and 30Y respectively.

[0067] Here, the uplink signal US is used by the sensor controller 31 to notify the pen 2 of the start timing of the frame used in signal transmission and reception, and to issue commands for controlling the pen 2. These commands include instructions specifying the time slot within the frame (described later), instructions specifying the data the pen 2 should transmit, etc. Upon receiving the uplink signal US, the pen 2 obtains the transmission and reception arrangement of the uplink signal US and the downlink signal DS according to the commands contained therein, generates the downlink signal DS, and transmits the generated downlink signal DS according to the obtained transmission and reception arrangement, and receives the next uplink signal US.

[0068] Furthermore, the downlink signal DS is a signal that includes a position signal and a data signal. The position signal is an unmodulated carrier signal (burst signal), and the data signal is a carrier signal modulated from the data transmitted by the sensor controller 31. The data transmitted via the data signal includes various data required for pairing (e.g., the pen ID mentioned above, hereinafter referred to as "pairing data"), a pen pressure value representing the pen pressure detected by the pen pressure detection sensor 22, etc. The sensor controller 31, upon receiving the downlink signal DS, derives the position of the pen 2 on the panel surface 3a based on the received strength of the position signals at each sensor electrode 30X, 30Y, and obtains the data transmitted by the pen 2 by demodulating the data signal. The derived position and the obtained data are thus sequentially supplied from the sensor controller 31 to the host processor 32.

[0069] Figure 3 This diagram illustrates the frame structure used for transmitting and receiving uplink signal US and downlink signal DS. As can be understood from the diagram, in this embodiment, the transmission and reception of uplink signal US and downlink signal DS are performed using time-division multiplexing, with each frame F divided into n time slots TS. It should be noted that frequency-division multiplexing or code-division multiplexing can be used instead of time-division multiplexing, or in conjunction with time-division multiplexing. Sensor controller 31 transmits uplink signal US in time slot TS1 at the beginning of each frame F. Pen 2 obtains the time position of frame F and each time slot TS by receiving uplink signal US, and uses some or all of the subsequent multiple time slots TS within the same frame F as the received uplink signal US to transmit downlink signal DS.

[0070] exist Figure 3 The diagram illustrates the newly paired state of pen 2 and sensor controller 31. Pen 2, not paired with sensor controller 31, continuously or intermittently receives uplink signal US (in...). Figure 3 (Referred to as "R" in the diagram). As a result of this receiving action, Pen 2, which receives the uplink signal US transmitted at the beginning of frame F1 (time t1) as shown in the diagram, uses the time slot TS2, which is predetermined for unpaired Pen 2, to transmit the downlink signal DS. At this time, Pen 2 configures pairing data in the data signal constituting the downlink signal DS. In addition, Pen 2 begins the receiving action of the uplink signal US at the beginning timing of frame F2, i.e., time t2.

[0071] The sensor controller 31, which receives pairing data from an unpaired pen 2, stores the received pairing data and determines one or more time slots TS to allocate to the pen 2. Then, for example, using the uplink signal US transmitted at the beginning of frame F2 (time t2), it notifies the pen 2 of the determined one or more time slots TS. Upon receiving this notification, the pen 2 determines that pairing is complete and, after frame F2, uses the notified one or more time slots TS to transmit the downlink signal DS. The sensor controller 31 determines that pairing is complete by receiving the downlink signal DS thus transmitted.

[0072] Here, the pairing data is, for example, a large amount of data exceeding 50 bits, and therefore, it may not be completely transmitted within one time slot TS. In this case, pen 2 can use the time slot TS2 of multiple frames F to transmit the downlink signal DS containing the pairing data. In this case, after receiving all the pairing data, sensor controller 31 determines to allocate more than one time slot TS to pen 2 that transmitted the pairing data, and notifies it using the uplink signal US.

[0073] return Figure 2 The host processor 32 is the central processing unit of the tablet terminal 3, which is responsible for executing the operating system and various applications of the tablet terminal 3 by reading and executing programs stored in a storage device (not shown).

[0074] The application executed by the host processor 32 includes a drawing application. The drawing application generates stroke data based on the positions and data (including pen pressure values) supplied sequentially from the sensor controller 31. Specifically, it generates curves such as Bézier curves and Catmull-Rom curves based on a series of positions, and controls the line width or transparency of the generated curves according to the pen pressure values, thereby generating stroke data. The drawing application renders the generated stroke data and supplies it to the aforementioned display device, thereby displaying the stroke data. Figure 1 Strokes are drawn on panel 3a as shown. Additionally, the drawing application performs the following processing: generates digital ink containing the generated stroke data, saves the digital ink to a storage device (not shown), and sends it to other computers.

[0075] The basic structure of the pen 2 and tablet terminal 3, and the basic processing performed by the pen 2 and sensor controller 31 have been explained above. Next, the processing performed by the pen 2 and sensor controller 31 to suppress the unnatural line width and transparency of the starting part of the stroke due to pairing will be explained in detail.

[0076] First, regarding the subject matter of this invention, while referring to... Figure 4 Let me explain again. Figure 4Figures (a) to (c) show the stroke data Sa to Sc when pen input begins from an unpaired state. Positions P1 to P8 in each figure show the positions derived by the sensor controller 31 based on the position signals sequentially sent from the pen 2. Furthermore, the size of the circle corresponding to each position P1 to P8 represents the pen pressure value (the value of the pen pressure detected by the pen pressure detection sensor 22 of the pen 2) at that point in time. Here, we illustrate this by showing how the sensor controller 31 controls the line width of the stroke data by deriving the envelope of these circles; however, the same applies to the case where the sensor controller 31 controls the transparency of the stroke data based on the pen pressure value.

[0077] Figure 4 (a) illustrates the ideal scenario where the pen pressure value is included in all downlink signals DS. In this scenario, the sensor controller 31 can correctly acquire the pen pressure value corresponding to each position P1 to P8. Here, as... Figure 4 As shown in (a), the sensor controller 31 is configured to control the line width of the stroke data by deriving the envelope of a circle representing the pen pressure value. Therefore, if all pen pressure values ​​are acquired correctly, then as shown in (a), the line width of the stroke data is controlled. Figure 4 Like the stroke data Sa shown in (a), it shows the natural starting point of the stroke that corresponds to the human action.

[0078] Figure 4 (b) illustrates the case where the pen pressure value is not included in the downlink signal DS corresponding to positions P1 and P2. As described above, the pen 2, during pairing, needs to configure a large amount of pairing data in the data signal constituting the downlink signal DS. As a result, sometimes even though the pen tip is in contact with the panel surface 3a, the pen pressure value cannot be configured in the data signal. Thus, as... Figure 4 (b) As illustrated, the sensor controller 31 is unable to obtain some positions corresponding to the beginning of a stroke (in Figure 4 In example (b), the pen pressure values ​​are those corresponding to positions P1 and P2.

[0079] In this situation, if the host processor 32 does not draw any strokes until the pen pressure value can be obtained, then... Figure 4 As shown in (b), there will be a discrepancy between the original starting position of the stroke and the actual starting position of the drawn stroke (the discrepancy of distance D in the figure). That is to say, although the user believes that he has also written to positions P1 and P2, the stroke is only drawn from position P3, which will give the user a sense of incongruity.

[0080] Figure 4 (c) shows as Figure 4One possible improvement to the situation described in (b) is a processing method whereby the host processor 32 treats the pen pressure value corresponding to position P3, which is derived immediately after positions P1 and P2, as the pen pressure value corresponding to positions P1 and P2, and generates stroke data accordingly. Thus, as... Figure 4 As shown in (c), stroke data is also depicted at positions P1 and P2, thus mitigating the aforementioned discrepancy problem, but the line width becomes unnatural at the beginning of the stroke.

[0081] In this embodiment, after the pairing process is completed, the pen 2 periodically sends an N-bit pen pressure value to the sensor controller 31. On the other hand, during the period before the pairing process is completed, the pen 2 sends a shortened pen pressure value consisting of the higher M bits (shorter than N bits) of the pen pressure value to the sensor controller 31, thereby solving the aforementioned problem. Hereinafter, the processing flow of the pen 2 and the sensor controller 31 will be described in detail.

[0082] Figure 5 This is a flowchart showing the processing performed by the circuit section 23 of the pen 2. The initial state of the processing shown in the figure is that the pen 2 and the sensor controller 31 are not paired. As shown in the figure, the circuit section 23 first performs the uplink signal US reception operation (step S1). Then, it determines whether the uplink signal US has been received (step S2). If it has not been received, it waits for the uplink signal US to be received by repeatedly executing the process of step S1.

[0083] On the other hand, if it is determined in step S2 that a signal has been received, the circuit unit 23 executes the action corresponding to the command contained in the uplink signal US (step S3). For example, if the command instructs the transmission of certain data, the action performed in step S3 becomes the action of generating a downlink signal DS containing that data. Furthermore, if the command notifies a local ID, the action performed in step S3 becomes the action of saving that local ID to memory. Moreover, if the command refers to a time slot (or frequency or spreading code), the action performed in step S3 becomes the action of determining the transmission and reception arrangement of the uplink signal US and the downlink signal DS and saving information indicating the determined transmission and reception arrangement and information indicating pairing to memory.

[0084] The circuit unit 23 further obtains the frame start timing based on the uplink signal US reception timing (step S4). The circuit unit 23 then performs subsequent uplink signal US reception and downlink signal DS transmission based on the timing obtained here and the transmission / reception arrangement determined in step S3.

[0085] Next, the circuit unit 23 determines whether pairing with the sensor controller 31 has been completed (step S5). Then, the circuit unit 31 that determines that pairing has not been completed transmits the downlink signal DS including the shortened pen pressure value and pairing data in accordance with the acquired transmission / reception schedule and the frame start timing (step S6). The shortened pen pressure value will be described in detail later. On the other hand, when it is determined in step S5 that pairing has been completed, the circuit unit 23 transmits the downlink signal DS including the pen pressure value in accordance with the acquired transmission / reception schedule and the frame start timing (step S7).

[0086] The circuit unit 23 that has completed step S6 or step S7 performs the reception operation of the uplink signal US in accordance with the acquired transmission / reception schedule and the frame start timing (step S8), and based on the result, determines whether a pairing cancellation condition such as that the uplink signal US is not received within a prescribed period is satisfied (step S9). The sensor controller 31 that makes a positive determination here cancels the pairing (step S10), and returns to step S1 to continue the processing. On the other hand, the sensor controller 31 that makes a negative determination in step S9 returns to step S3 to continue the processing.

[0087] Figure 6 (a) is a diagram illustrating the downlink signal DS transmitted by the circuit unit 23 in step S6, Figure 6 (b) is a diagram illustrating the downlink signal DS transmitted by the circuit unit 23 in step S7. As shown in these diagrams, each of the downlink signals DS is configured to include a position signal PS and a data signal DATA, while the content of the data signal DATA differs between step S6 and step S7.

[0088] Specifically, the data signal DATA (second data signal) transmitted in step S6 includes the shortened pen pressure value SPRD and the pairing data PAIRD, and the data signal DATA (first data signal) transmitted in step S7 is configured to include the pen pressure value PRD and other data. Note that the other data includes data indicating the on / off state of a switch provided on the surface of the pen 2, and the like.

[0089] Figure 7 (a) is a diagram illustrating an example of the structure of the pen pressure value PRD, Figure 7 (b) is a diagram illustrating the structure of the shortened pen pressure value SPRD corresponding to the pen pressure value PRD shown in (a). Figure 7 As shown in (a), the pen pressure value PRD is N-bit data (N is a natural number equal to or greater than 2), and N=11 in this example. Figure 7 Further, as shown in (b), the shortened pen pressure value SPRD is constituted by a high-order M-bit portion (1≤M<N) that is shorter than N bits in the pen pressure value PRD. Figure 7 In the Figure 7Example M=5 is shown in (b). In this way, the shortened pen pressure value SPRD is obtained by extracting only the high M bits from the original pen pressure value PRD. As a result, the possibility of sending the pairing data PAIRD when it is necessary to send it increases.

[0090] Figure 8 This is a flowchart illustrating the processing performed by the sensor controller 31. As shown in the figure, the sensor controller 31 first transmits the uplink signal US in the first time slot TS of the frame (step S20), and then performs the downlink signal DS reception operation in subsequent time slots (step S21). Then, it determines whether there is a pen 2 that meets the pairing release condition, such as the downlink signal DS not being received within a specified period (step S22). If it is determined that there is, the pairing with the pen 2 that meets the release condition is released (step S23).

[0091] If, in step S22, it is determined that there is no pen 2 that meets the pairing release condition, or if step S23 is completed, the sensor controller 31 performs the processing steps S25 to S29 (step S24) for each pen 2 that receives the downlink signal DS.

[0092] Specifically, the sensor controller 31 first bases its data on each sensor electrode 30X, 30Y (refer to...). Figure 2 The position of the pen 2 to be processed is derived from the received strength of the position signal PS at point (step S25). Next, the sensor controller 31 determines whether it has been paired with the pen 2 to be processed (step S26). The result of this determination is confirmed by saving the information indicating that it has been paired to the memory in step S29, which will be described later.

[0093] In step S26, the sensor controller 31 that is determined to be paired obtains the pen pressure value PRD by retrieving the pen pressure value PRD from the data signal DATA (step S27), and then moves the processing to step S29. On the other hand, the sensor controller 31 that is determined not to be paired in step S26, after performing the processing of deriving the pen pressure value PRD based on the shortened pen pressure value SPRD contained in the data signal DATA (step S28), moves the processing to step S29.

[0094] Figure 7 (c) shows the effect of shortening the pen pressure value SPRD. Figure 7(b) shows a graph of the pen pressure value PRD derived in step S28 when the pen pressure value SPRD is shortened. As shown in the graph, the sensor controller 31 is configured to derive the pen pressure value PRD by using the shortened pen pressure value SPRD as the high M bits of an N-bit pen pressure value PRD and supplementing the low NM bits with a predetermined value. The supplemented predetermined value is preferably set to "0" as shown in the figure, but it can also be set to "1". The pen pressure value PRD derived in this way contains errors, but the high M bits are correct; therefore, as shown in the figure... Figure 7 (a) shows the correct pen pressure value PRD (=1238) as understood, which is closer to the correct pen pressure value PRD (=1216).

[0095] return Figure 8 In step S29, the sensor controller 31 performs an action corresponding to the position derived in step S25, the pen pressure value PRD obtained or derived in steps S27 and S28, and other data contained in the data signal (step S29). Specifically, the sensor controller 31 supplies the derived position and the obtained or derived pen pressure value to the host processor 32. The host processor 32 generates stroke data based on the supplied position and pen pressure value. Furthermore, for example, when receiving pairing data from pen 2 during pairing, the sensor controller 31 saves the pairing data to memory. Upon receiving all the required pairing data, it further performs the following processing: saving information indicating pairing to memory, determining the time slot (or frequency or spreading code) allocated to pen 2, and configuring data representing the determined time slot (or frequency or spreading code) to the subsequently transmitted uplink signal US. When the processing of steps S25 to S29 is completed for all pen 2 receiving the downlink signal DS, the sensor controller 31 returns to step S20 and continues processing.

[0096] As explained above, according to System 1 of this embodiment, even when the N-bit pen pressure value PRD cannot be transmitted, the pen 2 can still transmit a shortened pen pressure value SPRD consisting of the high M bits of the pen pressure value PRD. Therefore, it is possible to suppress the unnatural line width and transparency of the starting part of the stroke due to pairing.

[0097] While the preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments in any way, and the present invention can certainly be implemented in various ways without departing from its spirit.

Claims

1. A system comprising a pen and a sensor controller paired via bidirectional communication, wherein the pen periodically sends an N-bit pen pressure value to the sensor controller, wherein... After the pairing process is completed, the pen periodically sends the pen pressure value. On the other hand, during the period before the pairing process is completed, a shortened pen pressure value is sent instead of the pen pressure value. This shortened pen pressure value consists of the high M bits of the pen pressure value that are shorter than the N bits.

2. The system according to claim 1, When the sensor controller receives the shortened pen pressure value from the pen, it obtains the pen pressure value by supplementing the low-order NM bits with a predetermined value.

3. The system according to claim 2, After the pairing process is completed, the sensor controller obtains the pen pressure value by extracting the pen pressure value from the data signal sent by the pen. During the period before the pairing process is completed, the pen pressure value is obtained by supplementing the low NM bits of the shortened pen pressure value contained in the data signal with a predetermined value.

4. The system according to any one of claims 1 to 3, After the pairing process is completed, the pen sends a first data signal containing the pen pressure value along with a position signal, and during the period before the pairing process is completed, it sends a second data signal containing the shortened pen pressure value along with a position signal.

5. The system according to claim 4, The second data signal includes at least a portion of the pen ID pre-written to the pen.

6. A pen that pairs with a sensor controller via bidirectional communication and periodically sends an N-bit pen pressure value to the sensor controller, wherein... After the pairing process is completed, the pen pressure value is periodically sent. On the other hand, during the period before the pairing process is completed, a shortened pen pressure value is sent instead of the pen pressure value. This shortened pen pressure value consists of the high M bits of the pen pressure value that are shorter than the N bits.

7. A sensor controller, which pairs with a pen via bidirectional communication, and periodically receives N bits of pen pressure values ​​from the pen, wherein, During the period before the pairing process is completed, the pen sends a shortened pen pressure value from the sensor controller, consisting of the higher M bits of the pen pressure value that are shorter than N bits. In the case where the pen receives a shortened pen pressure value consisting of the higher M bits that are shorter than the N bits, the pen pressure value is obtained by supplementing the lower NM bits with a predetermined value.

8. The sensor controller according to claim 7, After the pairing process is completed, the pen pressure value is obtained by extracting the pen pressure value from the data signal sent by the pen. During the period before the processing for the pairing is completed, the pen pressure value is obtained by supplementing the low NM bits of the shortened pen pressure value contained in the data signal with a predetermined value.

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