JP2019207596A - Writing input device - Google Patents

Abstract

To provide a writing input device capable of appropriately determining the ON state and OFF state of an electronic pen.SOLUTION: A writing input device 1 comprises: a detection value acquisition section 171 for acquiring a writing force value for a stylus pen 20; a differential value calculation section 172 for, based on a plurality of the writing force values acquired by the detection value acquisition section 171, calculating a differential value expressing a ratio in changes of the writing force values to temporal changes; and a determination processing section 174 for, based on the differential value calculated by the differential value calculation section 172, determining whether the stylus pen 20 is in an ON state or in an OFF state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a writing input device, and more particularly to a writing input device including a touch panel and an electronic pen.

  Conventionally, a system that detects writing pressure and coordinates and displays handwritten information on a display panel when a user performs handwriting on a touch panel with an electronic pen (stylus pen) is known (see, for example, Patent Document 1).

  In the conventional system, when the writing pressure of the electronic pen is equal to or greater than the threshold, it is determined that the handwriting input is performed, i.e., the electronic pen is on, and the writing pressure of the electronic pen is less than the threshold. It is determined that handwriting input is not performed, that is, the electronic pen is in an off state.

JP 2011-227580 A

  Here, the electronic pen has an inherent characteristic in structure. For example, the pen pressure values detected by the pen pressure sensor vary in each of the plurality of electronic pens. For this reason, in a plurality of electronic pens, variation occurs in the threshold value of the pen pressure for determining the on state and the off state of the electronic pen. Therefore, in the conventional system that determines the on state and the off state of the electronic pen based on whether or not the writing pressure exceeds the threshold value, it is difficult to appropriately determine the on state and the off state.

  An object of the present invention is to provide a writing input device capable of appropriately discriminating between an on state and an off state of an electronic pen.

  A writing input device according to an aspect of the present invention includes a writing pressure acquisition unit that acquires a writing pressure value of an electronic pen, and a change in time based on the plurality of writing pressure values acquired by the writing pressure acquisition unit. A differential value calculation unit that calculates a differential value indicating a rate of change in the writing pressure value with respect to the electronic pen, and the electronic pen is in an on state or an off state based on the differential value calculated by the differential value calculation unit And a determination processing unit for determining whether or not.

  According to the present invention, it is possible to appropriately determine the on state and the off state of the electronic pen.

FIG. 1 is a schematic diagram showing an overall configuration of a writing input apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the writing input device according to the embodiment of the present invention. FIG. 3 is a conceptual diagram showing an example of a pen management table of the writing input device according to the embodiment of the present invention. FIG. 4 is a conceptual diagram showing an example of a color assignment table of the writing input device according to the embodiment of the present invention. FIG. 5 is a block diagram showing the configuration of the stylus pen according to the embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a writing pressure value table of the writing input device according to the embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a graph representing a change in writing pressure value with respect to a change in time of the writing input device according to the embodiment of the present invention. FIG. 8 is a diagram illustrating an example of a differential value table of the writing input device according to the embodiment of the present invention. FIG. 9 is a diagram illustrating an example of a threshold setting screen of the writing input device according to the embodiment of the present invention. FIG. 10 is a flowchart showing an example of processing executed by the writing input device according to the embodiment of the present invention. FIG. 11 is a flowchart showing an example of processing executed by the writing input device according to the embodiment of the present invention. FIG. 12 is a diagram illustrating an example of a graph representing a change in writing pressure value with respect to a change in time and a graph representing an on state and an off state of a stylus pen in the writing input device according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: It does not have the character which limits the technical scope of this invention.

[Embodiment 1]
FIG. 1 is a schematic diagram showing an overall configuration of a writing input apparatus 1 according to Embodiment 1 of the present invention. The writing input device 1 includes a display panel 1A, a touch panel 1B (an example of a writing board of the present invention), and a stylus pen 20 (an example of an electronic pen of the present invention). The writing input device 1 receives an operation input using the stylus pen 20 on the touch panel 1B, and displays various information on the display panel 1A based on the received operation input.

  The writing input device 1 has a function equivalent to, for example, a personal computer, and is configured such that an OS (Operating System) or the like is activated when the power is turned on, and various driver software, application software, and the like operate on the activated OS. Has been. The writing input device 1 provides a GUI environment to the user by displaying objects such as a GUI component such as a desktop, an icon, a button, a menu, and a window on the display panel 1A after the OS is started. The object includes a setting screen (for example, a threshold setting screen described later (see FIG. 9)) for the user to input various parameters and the like.

  The user can cause the writing input apparatus 1 to execute various processes by performing operations on the operation target object using the stylus pen 20. The writing input device 1 detects an operation performed using the stylus pen 20 on the touch panel 1B, a process of starting an application according to the detected operation, a process of displaying the contents of a file indicated by an icon, a button Various processes such as a process for executing the function assigned to the menu, a process for displaying a menu, and a process for moving a window are executed.

  As one of the application software provided in the writing input device 1, pen software for displaying a line (handwritten line) corresponding to a locus drawn on the screen on the display panel 1A is included. The writing input device 1 executes the pen software, detects the position on the touch panel 1B designated by the stylus pen 20 in time series, identifies the locus drawn on the screen, and corresponds to the identified locus. The function to display the line to be displayed on the display panel 1A is realized.

  The writing input device 1 may be configured such that a plurality of stylus pens 20 can be used. For example, in the pen software described above, two users can display handwritten characters and line drawings on the display panel 1A by drawing handwritten characters and line drawings on the touch panel 1B using different stylus pens 20, respectively. it can. Moreover, the structure which can assign a display color to each stylus pen 20 may be sufficient so that the display color at the time of displaying a handwritten character and a line drawing may not overlap between several stylus pens 20.

  Note that the number of stylus pens 20 that can be used in the writing input device 1 is not limited to two, and may be three or more.

  FIG. 2 is a block diagram showing the configuration of the writing input device 1. The writing input device 1 includes a control device 10 that controls operations of the display panel 1A and the touch panel 1B. The control device 10 includes a main control unit 11, a storage unit 12, a pen connection unit 13, a backlight control unit 14, a display control unit 15, a touch panel control unit 16, and a pen control unit 17.

  The main control unit 11 is configured by, for example, a CPU, a RAM, and the like. The CPU of the main control unit 11 controls the operation of each of the above-described hardware units by loading a computer program such as the OS and various driver software into the RAM and executing it, and the entire device is used as the writing input device according to the present invention. Make it work.

  The storage unit 12 is a nonvolatile storage unit such as an EEPROM (Electrically Erasable and Programmable ROM), a flash memory, or an HDD (Hard Disk Drive). The storage unit 12 stores an OS executed by the main control unit 11, driver software, various application software including pen software, data used by a program such as the OS, and the like. The storage unit 12 also includes a pen management table that stores information on the registered stylus pen 20, a color assignment table that stores information such as display colors assigned to the stylus pen 20, and the like.

  The pen connection unit 13 includes a mounting unit 13 </ b> A for mounting the wireless dongle 18. The wireless dongle 18 has a function of performing wireless communication with a plurality of stylus pens 20. As the wireless communication between the wireless dongle 18 and the plurality of stylus pens 20, for example, wireless communication compliant with the IEEE 802.11 standard, Bluetooth (registered trademark), ZigBee (registered trademark), infrared communication, or the like may be adopted. it can. By performing a predetermined operation (for example, pressing operation of a registration button not shown) in each of the plurality of stylus pens 20 with the wireless dongle 18 mounted on the mounting unit 13A of the pen connection unit 13, the plurality of stylus pens. 20 is registered in the wireless dongle 18.

  The writing input device 1 acquires information on a plurality of registered stylus pens 20 through the wireless dongle 18 and manages the information on the registered plurality of stylus pens 20 in a pen management table in the storage unit 12.

  In the present embodiment, a plurality of stylus pens 20 are registered using the wireless dongle 18, but communication is performed directly between the writing input device 1 and the stylus pen 20 without using the wireless dongle 18. It is good also as a structure which registers the stylus pen 20 in the writing input device 1 by performing.

  A backlight (not shown) is connected to the backlight control unit 14, and the display panel 1 </ b> A is connected to the display control unit 15. The backlight includes a light source such as a white LED (Light Emitting Diode) or a cold cathode fluorescent tube, and illuminates the display panel 1A from the back side. The backlight control unit 14 controls turning on and off of the light source of the backlight in accordance with instructions from the main control unit 11. The display panel 1A is, for example, a color liquid crystal panel, and displays various information such as images and characters by the display control unit 15 driving the display panel 1A according to instructions from the main control unit 11.

  The touch panel 1B is connected to the touch panel control unit 16. The touch panel 1B is disposed on the front side (display side) of the display panel 1A, and includes a touch sensor (not shown) for detecting an operation by the stylus pen 20 on the touch panel 1B. As such a touch sensor, a sensor of a capacitance method, a resistance film method, an electromagnetic induction method, an infrared method, or the like can be used. The touch sensor may be configured to detect a contact state between the stylus pen 20 and the touch panel 1B, and may be configured to detect not only a contact state between the stylus pen 20 and the touch panel 1B but also a proximity state. Good.

  The touch panel control unit 16 controls the operation of the touch sensor, detects the position on the touch panel 1B designated by the stylus pen 20 based on the output from the touch sensor, and outputs the position information of the detected position to the main control unit. 11 to send. The main control unit 11 executes a process of specifying a locus drawn on the touch panel 1B according to the position information transmitted from the touch panel control unit 16.

  Based on the information acquired from the stylus pen 20, the pen control unit 17 is in a state where handwriting input is performed by the stylus pen 20, that is, a state where the pen tip portion of the stylus pen 20 is pressed (on state), and a stylus. A process of appropriately determining a state in which handwriting input by the pen 20 is not performed, that is, a state in which the pen tip portion of the stylus pen 20 is not pressed (off state) is performed. Specific processing of the pen control unit 17 will be described later.

  Next, each table provided in the writing input device 1 will be described.

  FIG. 3 is a conceptual diagram illustrating an example of a pen management table. The pen management table stores an ID (pen ID) assigned to each stylus pen 20 and an identifier that is unique information of the stylus pen 20 in association with each other.

  The pen ID is represented by an integer value of 1 to M (M is the number of registered stylus pens 20), for example. The identifier is unique information that can uniquely identify the stylus pen 20 such as a manufacturing number and a serial number of the stylus pen 20, and is represented by alphanumeric characters and symbols, for example.

  When registering the stylus pen 20, the wireless dongle 18 assigns a pen ID to the stylus pen 20 and acquires an identifier from the stylus pen 20. Further, the main control unit 11 acquires the pen ID and identifier of the stylus pen 20 registered in the wireless dongle 18 through the pen connection unit 13 and stores them in the pen management table in the storage unit 12.

  The example shown in FIG. 3 shows a state in which two stylus pens 20 are registered, the pen ID “1” is assigned to the stylus pen 20 with the identifier (1), and the stylus with the identifier (2). This indicates that the pen ID “2” is assigned to the pen 20.

  FIG. 4 is a conceptual diagram showing an example of a color assignment table. The color assignment table stores the display color (color name) when displaying handwritten characters and line drawings, the color code of each display color, and the pen ID of the stylus pen 20 to which the display color is assigned. In the present embodiment, black, red, blue, green, and yellow are defined as display colors. Each display color has a unique color code defined in advance. The display color for the stylus pen 20 may be automatically set in the writing input device 1 or manually set by the user.

  FIG. 5 is a block diagram showing a configuration of the stylus pen 20. The stylus pen 20 includes a control unit 21, a pressure sensor 22, an acceleration sensor 23, a switch 24, an LED 25, and an antenna 26. The stylus pen 20 performs wireless communication with the control device 10 via the antenna 26.

  The control unit 21 is configured by, for example, a CPU, a RAM, and the like. The CPU of the control unit 21 controls the operation of the stylus pen 20 by loading a computer program into the RAM and executing it.

  The pressure sensor 22 is constituted by, for example, a semiconductor piezoresistive pressure sensor, and a semiconductor strain gauge is formed on the surface of a diaphragm (not shown). Therefore, when the pen tip portion is pressed against the touch panel 1B during the touch operation, the pen tip shaft is pushed through the pen tip portion and presses the surface of the diaphragm of the pressure sensor 22, thereby deforming and generating the diaphragm. Changes in electrical resistance due to the piezoresistive effect are converted into electrical signals. Thereby, the writing pressure (pressure) in the stylus pen 20 can be detected. In addition, the structure which detects a pen pressure is not limited to this, A well-known structure is employable.

  The pressure sensor 22 detects the writing pressure with a sampling frequency of 1 ms (1 ms), for example.

  The acceleration sensor 23 is a triaxial acceleration sensor that detects acceleration in three axial directions orthogonal to each other. The acceleration detected by the acceleration sensor 23 is a displacement value accompanying the movement of the acceleration sensor 23 in the left and right (X-axis direction), up and down (Y-axis direction), and front and rear (Z-axis direction). That is, by integrating the acceleration data or the like, it is possible to calculate the amount of movement of the stylus pen 20 left, right, up, down, and forward and backward with reference to the posture (three-dimensional reference position) of the stylus pen 20 at a predetermined time.

  The control unit 21 transmits the detection value (writing pressure value) detected by the pressure sensor 22 and the detection value (acceleration) detected by the acceleration sensor 23 to the control device 10 in association with the pen ID of the stylus pen 20. To do. The control unit 21 converts each detected value from analog data to digital data and transmits the converted data to the control device 10.

  The switch 24 is an operation switch for turning on / off the power of the stylus pen 20. The LED 25 is an indicator for displaying a remaining battery level (not shown).

  Next, specific processing of the pen control unit 17 (see FIG. 2) of the control device 10 will be described. The pen control unit 17 includes a detection value acquisition unit 171, a differential value calculation unit 172, a setting processing unit 173, and a determination processing unit 174.

  The detection value acquisition unit 171 acquires the pen pressure value detected by the pressure sensor 22 of the stylus pen 20. For example, the detection value acquisition unit 171 sequentially acquires pen pressure values detected at a sampling frequency of 1 ms and stores them in the pen pressure value table. FIG. 6 is a diagram illustrating an example of a writing pressure value table. In the pen pressure value table, N storage tables Tg (n) are set in advance, and the detection value acquisition unit 171 stores the pen pressure values in the order in which the pen pressure values are acquired from the stylus pen 20 (in time series). To do. In the example shown in FIG. 6, ten storage tables Tg (0) to Tg (9) and pen pressure values G (0) to G (9) stored in the respective storage tables are shown. The detection value acquisition unit 171 converts the detection value detected by the pressure sensor 22 of the stylus pen 20 into 1024 levels (0 level to 1023 level), and uses the converted value as a writing pressure value in the writing pressure value table. Store. The detection value acquisition unit 171 is an example of a writing pressure acquisition unit of the present invention.

  The detection value acquisition unit 171 acquires acceleration detected by the acceleration sensor 23 of the stylus pen 20 at a predetermined cycle. The detection value acquisition unit 171 is an example of the acceleration acquisition unit of the present invention.

  The differential value calculation unit 172 calculates a differential value based on the pen pressure value acquired by the detection value acquisition unit 171. Specifically, the differential value calculation unit 172 writes the pen pressure values G (n) and G (n) stored in the storage tables Tg (n) and Tg (n−1) of the pen pressure value table (see FIG. 6). Based on (-1), a differential value indicating a ratio of a change in writing pressure value with respect to a change in time is calculated. The differential value d (n) indicates a slope in a graph representing a change in writing pressure value with respect to a change in time. FIG. 7 shows an example of a graph representing a change in writing pressure value with respect to a change in time t. In the graph shown in FIG. 7, the change in the pen pressure value according to a series of operations from the state in which the stylus pen 20 contacts and touches the touch panel 1B to the state in which the stylus pen 20 leaves the touch panel 1B and turns off is shown. Show.

  The differential value calculation unit 172 stores the calculated differential value d (n) in the differential value table. FIG. 8 is a diagram illustrating an example of the differential value table. In the differential value table, N storage tables are set in advance, and the differential value calculation unit 172 stores the differential values d (n) in the storage table in the order of calculation (time series). In the example shown in FIG. 8, ten storage tables Td (0) to Td (9) and differential values d (0) to d (9) stored in the respective storage tables are shown.

  The determination processing unit 174 performs a writing pressure determination process for determining whether the pen tip portion of the stylus pen 20 is pressed (on state) or not pressed (off state). Specifically, the determination processing unit 174 performs the writing pressure determination process based on the differential value calculated by the differential value calculation unit 172. For example, the determination processing unit 174 determines that the differential value (see FIG. 8) calculated by the differential value calculation unit 172 is the ON state when the differential value (see FIG. 8) is continuously equal to or more than the first threshold value five times. Then, when it is less than the second threshold value five times, it is determined to be in the off state.

  In addition, the determination processing unit 174 executes posture determination processing for determining the posture of the stylus pen 20. Specifically, the determination processing unit 174 performs the posture determination process based on the acceleration acquired by the detection value acquisition unit 171. For example, the determination processing unit 174 determines that the stylus pen 20 is held by the user when the acceleration acquired by the detection value acquisition unit 171 is equal to or greater than a third threshold, and the acceleration is less than the third threshold. In this case, it is determined that the stylus pen 20 is not held by the user and is left (still state).

  In addition, the pen control unit 17 sets the writing pressure value detected by the pressure sensor 22 when the acceleration is less than the third threshold as the initial value of the pressure sensor 22. For example, the pen control unit 17 sets an average value of a plurality of pen pressure values stored in the pen pressure value table (see FIG. 6) as the initial value when the acceleration becomes less than the third threshold. The initial value represents a writing pressure value in an initial state (when power is turned on) unique to the stylus pen 20.

  The setting processing unit 173 sets the first threshold value, the second threshold value, and the third threshold value described above. For example, the setting processing unit 173 sets the first threshold value, the second threshold value, and the third threshold value on the threshold value setting screen D1 displayed on the display panel 1A based on the parameter (coefficient) input by the user. The display control unit 15 causes the display panel 1A to display a threshold setting screen D1 for accepting input of parameters for setting the first threshold and the second threshold from the user.

  FIG. 9 is a diagram illustrating an example of the threshold setting screen D1. In the threshold value setting screen D1 shown in FIG. 9, the start inclination coefficient As (parameter) for the pen pressure detection setting is the first slope coefficient (start inclination) when the pen pressure value increases with time in the graph shown in FIG. A coefficient corresponding to one threshold is shown. The user inputs “As” on the threshold setting screen D1. For example, when the drive voltage of the stylus pen 20 is 3.3 V, the first threshold value is calculated as (As × 1 [ms] /3.3) × 1024.

  In addition, in the threshold setting screen D1 shown in FIG. 9, the end slope coefficient Ae (parameter) for the pen pressure detection setting is the slope (end slope) when the pen pressure value decreases over time in the graph shown in FIG. 7. A coefficient corresponding to the second threshold is shown. The user inputs “Ae” on the threshold setting screen D1. For example, when the driving voltage of the stylus pen 20 is 3.3 V, the second threshold value is calculated as (Ae × 1 [ms] /3.3) × 1024. The first threshold value is a positive value, and the second threshold value is a negative value.

  In the threshold setting screen D1 shown in FIG. 9, the acceleration coefficient Aa for calibration setting is a coefficient (parameter) indicating the third threshold and is input by the user. The acceleration coefficient Aa is a value serving as a threshold value for determining whether the stylus pen 20 is held by the user or left, and is set to 1.5 g (g = 9.8 m / s ^ 2), for example. . When the acceleration detected by the acceleration sensor 23 is less than the acceleration coefficient, a process (calibration process) for setting the writing pressure value detected by the pressure sensor 22 to the initial value of the pressure sensor 22 is executed. The calibration process is executed every time acceleration is acquired by the detection value acquisition unit 171. In the calibration process, the pen control unit 17 may perform a process of changing the writing pressure value detected by the pressure sensor 22 according to the initial value. For example, the pen control unit 17 changes the writing pressure value according to the fluctuation amount (change rate) of the initial value.

  The pen control unit 17 acquires unique information such as a pen ID and a display color from the stylus pen 20 when the stylus pen 20 is in an on state. The display control unit 15 displays a line (handwritten line) corresponding to the locus drawn by the stylus pen 2 based on the pen information and the position information indicating the position on the touch panel 1B designated by the stylus pen 20. Display on panel 1A. When the stylus pen 20 is in the off state, the pen control unit 17 does not acquire the pen information, and the display process by the display control unit 15 is not performed.

  Hereinafter, an example of a procedure of processing executed by the pen control unit 17 of the control device 10 will be described using the flowcharts of FIGS. 10 and 11. Here, it is assumed that the setting processing unit 173 sets the first threshold value to “+10”, the second threshold value to “−10”, and the third threshold value to “1.5 g”. The pressure sensor 22 of the stylus pen 20 detects the writing pressure value at a sampling frequency of 1 ms, for example. 10 and 11, S101, S102,... Indicate processing procedure numbers (step numbers).

  When the power of the writing input device 1 is turned on, for example, when the pen software is activated, the pressure sensor 22 of the stylus pen 20 starts detecting the writing pressure value, and the pen control unit 17 (detected value acquisition unit 171) The pen pressure value detected by is acquired. First, the detection value acquisition unit 171 acquires the pen pressure value G (0) detected by the pressure sensor 22 and stores it in the storage table Tg (0) of the pen pressure value table (see FIG. 6) (S101). The writing pressure value G (0) is set to an initial value in order to correspond to the detection value by the pressure sensor 22 of the stylus pen 20 when the power is turned on.

  Next, when 1 ms elapses (S102), the pen control unit 17 increments the variable “n” of the storage table Tg (n) (S103). The detection value acquisition unit 171 acquires the pen pressure value G (1) detected by the pressure sensor 22 and stores it in the storage table Tg (1) of the pen pressure value table (see FIG. 6) (S104).

  Next, when the variable “n” is not “0” (S105: NO), the process proceeds to S106, and the pen control unit 17 (differential value calculation unit 172) stores the writing pressure value table (see FIG. 6). A differential value d (n) is calculated based on the pen pressure values G (n) and G (n−1) stored in the tables Tg (n) and Tg (n−1). Here, the pen control unit 17 (differential value calculation unit 172) calculates a differential value based on the pen pressure values G (0) and G (1). The differential value calculation unit 172 stores the calculated differential value d (1) in the storage table Td (1) of the differential value table (see FIG. 8).

  If the variable “n” is “0” (S105: YES), the process proceeds to S110, and the pen controller 17 (differential value calculator 172) stores the writing pressure value table (see FIG. 6). A differential value d (0) is calculated based on the pen pressure values G (0) and G (9) stored in the tables Tg (0) and Tg (9). The differential value calculation unit 172 stores the calculated differential value d (0) in the storage table Td (0) of the differential value table (see FIG. 8).

  Next, when the variable “n” is “8” or less (S107: NO), the process proceeds to S108, and the pen control unit 17 increments the variable “n” of the storage table Tg (n). Next, when 1 ms elapses (S109), the process proceeds to S112, and the pen control unit 17 (determination processing unit 174) determines the posture of the stylus pen 20 based on the acceleration acquired by the detection value acquisition unit 171. . Specifically, the pen control unit 17 (determination processing unit 174) determines whether or not the acceleration acquired by the detection value acquisition unit 171 is less than “1.5 g” (third threshold value).

  When the acceleration acquired by the detection value acquisition unit 171 is less than “1.5 g” (S112: YES), the pen control unit 17 executes the calibration process and detects the pen pressure value detected by the pressure sensor 22. Is set to the initial value of the pressure sensor 22 (S113). Here, the initial value G (0) set when the power is turned on is changed based on the pen pressure value stored in the pen pressure value table (see FIG. 6). For example, the pen control unit 17 sets the average value of the pen pressure values G (0) to G (9) stored in the pen pressure value table as the initial value. Thereafter, the process returns to S104. That is, when the acceleration acquired by the detection value acquisition unit 171 is less than “1.5 g” (S112: YES), the pen control unit 17 does not perform a process of determining the on state and the off state of the stylus pen 20. When the acceleration acquired by the detection value acquisition unit 171 exceeds “1.5 g” (S112: NO), the process proceeds to S114.

  In S114, the pen control unit 17 (determination processing unit 174) determines whether or not the differential value (see FIG. 8) calculated by the differential value calculation unit 172 is equal to or greater than the first threshold “+10” five times in succession. Determine whether. When the differential value is equal to or greater than the first threshold “+10” five times in succession (S114: YES), the pen control unit 17 (determination processing unit 174) has pressed the pen tip of the stylus pen 20. It determines with it being in a state (on state) (S115). Thereafter, the process returns to S104.

  When the differential value is continuously less than the first threshold “+10” five times (S114: NO), the process proceeds to S116. In S116, the pen control unit 17 (determination processing unit 174) determines whether or not the differential value is continuously less than the second threshold value “−10” five times. When the differential value is continuously less than the second threshold “−10” five times (S116: YES), the pen control unit 17 (determination processing unit 174) presses the pen tip of the stylus pen 20. It is determined that it is not in a state (off state) (S117). Thereafter, the process returns to S104. If the differential value is continuously equal to or greater than the second threshold “−10” five times (S116: NO), the process returns to S104. The pen control unit 17 repeats the processes of S104 to S117 described above.

  According to the writing input device 1 according to the present embodiment, the stylus pen 20 is turned on based on the ratio (differential value) of the change in the pen pressure value, that is, the slope in the graph representing the change in the pen pressure value with respect to the change in time. And determining the off state. Thereby, compared with the structure which discriminate | determines the ON state and OFF state of the stylus pen 20 based on the threshold value of a pen pressure value, an ON state and an OFF state can be discriminate | determined appropriately. For example, when structural variations occur in a plurality of stylus pens, the writing pressure values vary. Even in such a case, since the writing input device 1 determines the on state and the off state based on the rate of change in the writing pressure value, the on state and the off state can be appropriately determined.

  Moreover, according to the writing input device 1 which concerns on this embodiment, the said ON state and an OFF state can be discriminate | determined at an early stage. FIG. 12 shows a graph representing a change in writing pressure value with respect to a change in time and a graph representing an on state and an off state of the stylus pen 20. For example, the determination processing unit 174 determines that the differential value is in the ON state when the differential value is continuously the predetermined number of times (dotted line frame a in the figure) and the first threshold value or more, and the predetermined number of times (FIG. When the middle dotted line frame b) is less than the second threshold value, it is determined to be in the off state. That is, the determination processing unit 174 determines that it is on at time t1 and determines that it is off at time t3. On the other hand, in the configuration for determining the on state and the off state of the stylus pen 20 based on the threshold value p0 of the pen pressure value, it is determined that the stylus pen 20 is in the on state at time t2, and is determined to be in the off state at time t4. The Thus, according to the writing input device 1 according to the present embodiment, the ON state and the OFF state are compared with the configuration in which the ON state and the OFF state of the stylus pen 20 are determined based on the threshold value of the writing pressure value. It can be determined early.

  Moreover, according to the writing input device 1 according to the present embodiment, when the acceleration is equal to or greater than the third threshold, it is determined that the stylus pen 20 is held by the user, and when the acceleration is less than the third threshold, It is determined that the stylus pen 20 is not held by the user and is left. When the acceleration is less than the third threshold value, the determination processing unit 174 does not execute processing for determining the on state and the off state of the stylus pen 20. Thereby, when the user is not using the stylus pen 20, it is possible to avoid a malfunction that is determined to be in the on state. Further, it is possible to avoid a malfunction in which the ON state is maintained due to a structural defect of the stylus pen 20.

  Further, the writing pressure value detected by the pressure sensor 22 when the acceleration is less than the third threshold value is set to the initial value of the pressure sensor 22. Since the writing input device 1 according to the present embodiment is configured to determine the on state and the off state of the stylus pen 20 based on the change (differential value) of the writing pressure value, the initial state caused by manufacturing variations of the stylus pen 20 The fluctuation of the value can be absorbed. That is, even when manufacturing variations occur in the stylus pen 20, it is possible to appropriately determine the on state and the off state of the stylus pen 20.

[Embodiment 2]
In the writing input device 1 according to the second embodiment, the pen control unit 17 (determination processing unit 174) determines whether the stylus pen 20 is based on the change rate (differential value) of the writing pressure value and the threshold value of the writing pressure value. Discriminate between ON state and OFF state. For example, the determination processing unit 174 has at least one of a condition that the differential value is continuously a predetermined number of times (for example, 5 times) and the first threshold value or more, and a condition that the writing pressure value is the fourth threshold value or more. When the condition is satisfied, it is determined that the device is in the on state. In addition, the determination processing unit 174 has at least one of a condition that the differential value is continuously less than a second threshold value for a predetermined number of times (for example, 5 times) and a condition that the writing pressure value is less than a fifth threshold value. When the condition is satisfied, it is determined that the vehicle is in the off state. The fourth threshold value and the fifth threshold value may be the same writing pressure value or different writing pressure values.

  According to the writing input device 1 according to the second embodiment, for example, even when the differential value does not continuously exceed the first threshold value a predetermined number of times, the writing pressure value becomes the fourth threshold value or more. Thus, the determination processing unit 174 determines that the stylus pen 20 is on. Even if the writing pressure value does not become less than the fifth threshold value, the determination processing unit 174 determines that the stylus pen 20 is turned off when the differential value continuously becomes less than the second threshold value a predetermined number of times. It is determined that it is in a state. According to the writing input device 1 according to the second embodiment, the on state and the off state of the stylus pen 20 can be determined more reliably and early.

  In the calibration process, the pen control unit 17 changes the writing pressure value detected by the pressure sensor 22, the fourth threshold value, and the fifth threshold value according to the amount of change (change rate) of the initial value. May be.

  The writing input device 1 according to the present invention can be freely combined with the above-described embodiments within the scope of the invention described in each claim, or can be modified or partially modified as appropriate. It is also possible to configure by omitting.

1: Writing input device 1A: Display panel 1B: Touch panel 10: Control device 11: Main control unit 12: Storage unit 13: Pen connection unit 14: Backlight control unit 15: Display control unit 16: Touch panel control unit 17: Pen control Unit 20: Stylus pen 21: Control unit 22: Pressure sensor 23: Acceleration sensor 171: Detection value acquisition unit 172: Differential value calculation unit 173: Setting processing unit 174: Determination processing unit Aa: Acceleration coefficient Ae: End inclination coefficient As: Start slope coefficient D1: Threshold setting screen

Claims (9)

A writing pressure acquisition unit for acquiring a writing pressure value of the electronic pen;
Based on the plurality of writing pressure values acquired by the writing pressure acquisition unit, a differential value calculation unit that calculates a differential value indicating a ratio of the change in the writing pressure value with respect to a change in time,
A determination processing unit that determines whether the electronic pen is in an on state or an off state based on the differential value calculated by the differential value calculation unit;
A writing input device comprising: The determination processing unit determines that the electronic pen is in an on state when the differential value is equal to or greater than a preset first threshold value, and when the differential value is less than a preset second threshold value. Determining that the electronic pen is in an off state;
The writing input device according to claim 1, comprising: The determination processing unit determines that the electronic pen is in an ON state when the differential value is continuously equal to or greater than the first threshold value for a predetermined number of times, and is continuously less than the second threshold value for the predetermined number of times. It is determined that the electronic pen is in an off state.
The writing input device according to claim 2. An acceleration acquisition unit that acquires accelerations in three axial directions orthogonal to each other in the electronic pen;
The determination processing unit determines that the electronic pen is being held by a user when the acceleration acquired by the acceleration acquisition unit is equal to or greater than a preset third threshold, and the acceleration is determined by the third When the electronic pen is less than the threshold, it is determined that the electronic pen is not held by the user and is left;
The writing input device according to claim 2 or claim 3. The determination processing unit performs a process of determining whether the electronic pen is in an on state or an off state when the acceleration is equal to or greater than the third threshold, and the acceleration is less than the third threshold. If this process is not performed,
The writing input device according to claim 4. A display control unit for displaying on the display panel a setting screen for accepting input of parameters for setting the first threshold and the second threshold from a user;
A setting processing unit configured to set the first threshold and the second threshold based on the parameter;
The writing input device according to any one of claims 2 to 5, further comprising: The determination processing unit is configured such that the electronic pen is in an on state or an off state based on the differential value calculated by the differential value calculation unit and the writing pressure value acquired by the writing pressure acquisition unit. To determine whether
The writing input device according to claim 1. In the case where the determination processing unit satisfies at least one of a condition in which the differential value is equal to or greater than a preset first threshold value and a condition in which the writing pressure value is equal to or greater than a preset fourth threshold value. The electronic pen is determined to be in an on state, and at least one of a condition that the differential value is less than a preset second threshold value and a condition that the writing pressure value is less than a preset fifth threshold value If the condition is satisfied, the electronic pen is determined to be in an off state.
The writing input device according to claim 7. A display control unit configured to display a line corresponding to a locus drawn by the electronic pen on a display panel based on unique information of the electronic pen acquired from the electronic pen when the electronic pen is in an on state;
The writing input device according to any one of claims 1 to 8.

Images