JP5447341B2 - Electronic writing device - Google Patents

Description

  The present invention relates to an electronic writing apparatus capable of electronically inputting user writing contents.

  Conventionally, for example, Patent Literature 1 discloses an electronic writing device capable of electronically inputting user-written handwriting. In the tablet device with a display as the conventional electronic writing device, when a high frequency current is supplied from a high frequency power source to a coil as a magnetic field application coil built in a detection pen as an electronic writing instrument, a writing signal is supplied to the coil. As a result, a high frequency magnetic field is generated. And this high frequency magnetic field acts on the electrode of an electromagnetic induction type tablet, an induced voltage generate | occur | produces in an electrode, and the position of a detection pen is detected based on this induced voltage. At that time, the height of the detection pen is detected using the induced voltage from the pen height detection electrode provided at the tip of the detection pen, and the input mode is automatically determined. Supply high frequency current.

Japanese Patent No. 2766101

  In the above prior art, the height from the liquid crystal panel of the electronic writing instrument is detected, and only when the detected height is a predetermined value or less, the high frequency current can be automatically supplied to the magnetic field application coil of the electronic writing instrument, Power consumption can be saved. That is, the normal input mode and the power saving mode are switched by detecting the height of the electronic writing instrument from the liquid crystal panel. Therefore, for example, if the user leaves the electronic writing instrument on the liquid crystal panel without performing a power-off operation separately, the height of the electronic writing instrument from the liquid crystal panel is predetermined even though the electronic writing instrument is actually left unattended. Since the value is equal to or less than the value, it is considered that the electronic writing instrument is in the approaching state, and the position information of the electronic writing instrument is acquired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic writing apparatus that can reliably save power even if a user does not perform a power-off operation separately and can prevent wasteful power consumption.

  In order to achieve the above object, the first invention is the signal generating means of an electronic writing instrument which has signal generating means having a magnetic field applying coil and performs data input corresponding to the writing content to the writing object. Position information for acquiring position information of the electronic writing tool based on a plurality of main coils that can receive and output a writing signal for position detection generated and output, and the reception result of the writing signal by the plurality of main coils. Based on the frequency mode or output mode of the writing signal received by the acquisition means and the plurality of main coils, the electronic writing instrument is in a state of being left on the writing body or the writing State determination means for determining whether or not the input posture is a state of inputting data corresponding to the content, sequentially selecting each main coil at a predetermined cycle, and the writing signal of the selected main coil Based on the reception result The first mode in which the position information of the electronic writing instrument is acquired by the position information acquisition means is an operation mode different from the first mode, and is set to consume less power than the first mode. In the electronic writing device provided with the second mode, when the state determination means determines that the electronic writing instrument is in the state of being left in the state in which the operation mode is the first mode, When the operation mode is switched from the first mode to the second mode, and the state determination means determines that the electronic writing instrument is in the input posture state when the operation mode is the second mode, A mode switching means for switching the operation mode from the second mode to the first mode is provided.

  The electronic writing device according to the first invention of the present application includes a first mode and a second mode. The first mode is a mode for acquiring position information. That is, the position detection writing signals generated and output by the signal generation means of the electronic writing instrument are received by the plurality of main coils. Based on the reception result, position information of the electronic writing instrument is acquired by the position information acquisition means. Thereby, the movement locus | trajectory of the electronic writing instrument corresponding to the writing operation | movement when a user writes in a to-be-written body is acquired. On the other hand, the second mode is a mode that consumes less power than the first mode, corresponding to when the user interrupts the writing operation and leaves the electronic writing instrument on the writing object. When the user is performing a writing operation as described above, generally, the axial relationship between the magnetic field application coil of the electronic writing instrument and the direction of the writing surface of the writing object, that is, the coil surface direction intersect with each other. Become. On the other hand, if the user keeps the electronic writing instrument on the writing object, the axial direction of the magnetic field application coil of the electronic writing tool and the direction of the writing surface of the writing object, that is, the coil surface direction are , Become parallel. Due to this change in the positional relationship, the inductance of the coil is larger in the state where the electronic writing instrument is placed than in the state where the writing operation is performed, and the resonance frequency between the magnetic field application coil of the electronic writing instrument and the coil of the electronic writing device Becomes smaller. Further, due to the change in the positional relationship, the direction of the magnetic flux received by the coil changes between the state where the writing operation is performed and the state where the electronic writing instrument is placed, and the output voltage generated by the coil changes. As a result, the frequency mode and output mode of the writing signal detected by the coil from the magnetic field application coil of the electronic writing tool change.

  In the first invention of the present application, paying attention to this point, the state determination means places the electronic writing instrument on the writing body based on the frequency aspect and output aspect of the writing signal received by the plurality of main coils. It is determined whether the device is in an unattended posture or an input posture in which data input corresponding to written content is performed. In the first mode, when it is determined by the state determination means that the electronic writing instrument is in the state of being left unattended, the mode switching means switches the operation mode from the first mode to the second mode. As a result, when the user interrupts writing on the writing object and places the electronic writing instrument on the writing object and leaves it to stand, the leaving state is detected and the operation mode is changed from the first mode to the second mode. Is switched. As a result, even if the user does not perform a power-off operation separately, it is possible to reliably save power and to prevent wasteful power consumption.

  Further, in the second mode, when the state determination unit determines that the electronic writing instrument is in the input posture state, the mode switching unit switches the operation mode from the second mode to the first mode. As a result, when the user resumes writing on the cursive hand by again holding the electronic writing instrument left on the cursive body, the writing resume state is detected and the second mode is switched to the first mode. The operation mode is switched. As a result, it is possible to reliably resume the acquisition of the position information of the electronic writing instrument without the user performing a power-on operation separately. Moreover, acquisition of the position information of the electronic writing instrument does not fail due to the forgotten power-on operation.

In the first invention , the frequency of the writing signal is determined based on the reception result of the writing signal in the main coil or in the auxiliary coil that can receive the writing signal and is different from the main coil. A frequency detecting means for detecting, and when the frequency of the writing signal detected by the frequency detecting means is equal to or lower than a predetermined value, the electronic writing instrument is in the state of being left unattended. When the frequency of the writing signal detected by the frequency detection means is larger than a predetermined value, it is determined that the electronic writing instrument is in the input posture state.

  As a result, a state in which the user performs the writing operation with the electronic writing instrument in hand and a state in which the user leaves the electronic writing instrument on the object to be written on the magnetic field application coil of the electronic writing instrument and the coil of the electronic writing apparatus Can be identified by a change in the frequency value of the writing signal based on the change in the positional relationship between As a result, the configuration can be simplified and the cost can be reduced as compared with the case where a separate detection means such as a sensor is provided to detect the state of the electronic writing instrument.

In a second aspect based on the first aspect , in the first mode, the respective main coils are sequentially selected, and the writing by the frequency detecting means is performed based on a reception result of the writing signal by the selected main coils. In the mode in which the frequency of the signal is detected, the second mode selects the auxiliary coil in the previous period without selecting the main coil, and based on the reception result of the writing signal in the selected auxiliary coil, In this mode, the frequency of the writing signal is detected by the frequency detection means, and the mode determination means is received by the main coil detected by the frequency detection means when the operation mode is the first mode. When the frequency of the written writing signal is equal to or lower than the predetermined value, the state determining means determines that the electronic writing instrument is in the state of being left unattended. The operation mode is switched from the first mode to the second mode, and the frequency of the writing signal received by the auxiliary coil detected by the frequency detecting means when the operation mode is the second mode. Is greater than the predetermined value, the operation mode is returned from the second mode to the first mode when the state determination means determines that the electronic writing instrument has returned to the input posture state. It is characterized by that.

In the second invention of this application, the selection of the main coil is stopped and the auxiliary coil is selected in the second mode. When the frequency of the writing signal received by the selected auxiliary coil is greater than a predetermined value, the writing restart state is detected and the operation mode is switched from the second mode to the first mode. Thus, by canceling the selection of the main coil and performing reception with the auxiliary coil, it is possible to reliably realize power saving in the second mode.

A third invention is, power consumption is less than a and the first mode and the second mode different from the operation mode Oite, the first mode and the second mode to the first or second invention A frequency mode of the written signal received by the plurality of main coils or by an auxiliary coil different from the main coil in the state where the third mode is set and is switched to the second mode, or Based on the output mode, the apparatus further includes a separation determination unit that determines whether or not the electronic writing instrument is separated from the main coil or the auxiliary coil, and the mode switching unit is in a state where the operation mode is the second mode. When it is determined by the separation determining means that the electronic writing instrument is separated from the main coil or the auxiliary coil, the operation mode is set to the second mode. And switches to the third mode from the.

The electronic writing device according to the third aspect of the present invention further includes a third mode. The third mode is a mode that consumes less power than the first mode and the second mode, corresponding to when the user finishes the writing operation and moves the electronic writing instrument away from the writing object. As described above, when the electronic writing instrument is placed far away from the writing object from the state in which the user has left the electronic writing instrument on the writing object, the magnetic field application of the electronic writing instrument corresponds to this separation. The magnetic coupling state between the coil and the coil of the electronic writing device changes. Due to this change, the resonance frequency between the magnetic field application coil of the electronic writing instrument and the coil of the electronic writing device becomes unstable, or the output voltage generated in the coil by the writing signal becomes small. As a result, the frequency mode and output mode of the writing signal detected from the magnetic field application coil of the electronic writing tool change in the coil.

In the third invention of the present application, paying attention to this point, the electronic writing instrument is separated from the main coil or auxiliary coil based on the frequency aspect and output aspect of the writing signal received by the main coil or auxiliary coil. It is determined whether or not it is in a state. In the second mode, when it is determined by the separation determination unit that the electronic writing instrument is separated from the main coil or the auxiliary coil, the mode switching unit switches the operation mode from the second mode to the third mode. Thus, when the user finishes writing on the writing object and moves the electronic writing tool away from the writing object, the state is detected and the operation mode is switched from the second mode to the third mode. As a result, it is possible to reliably prevent wasteful power consumption in a manner that reflects the intention of the user to end writing.

A fourth invention is the main coil according to the third invention, based on a frequency mode or an output mode of the writing signal received by the plurality of main coils or the auxiliary coils in the state switched to the third mode. Or it further has an approach determining means for determining whether or not the electronic writing instrument has approached the auxiliary coil, and the mode switching means is operated by the approach determining means when the operation mode is the third mode. When it is determined that the electronic writing instrument is close to the main coil or the auxiliary coil, the operation mode is switched from the third mode to the first mode.

In the fourth invention of the present application, it is possible to cope with a case where the user intends to newly start writing on the writing body from a state where writing on the writing body is once completed. That is, in the fifth invention of the present application, when the user brings the electronic writing instrument from the state far away from the writing body to the writing body, the approaching state is detected and the mode switching means switches from the third mode to the first mode. And the operation mode can be switched. As a result, it is possible to reliably start acquisition of the position information of the electronic writing instrument in a manner that reliably reflects the user's intention to start writing.

In a fifth aspect based on the third or fourth aspect , the frequency of the writing signal detected by the frequency detection means based on the reception result of the writing signal by the auxiliary coil is in an indefinite state. Therefore, the electronic writing instrument is an indeterminate state determination unit that determines that the electronic writing instrument is in a state of being separated from the auxiliary coil, and the second mode selects the auxiliary coil without selecting the main coil, Based on the reception result of the writing signal at the selected auxiliary coil, the frequency detection unit detects the frequency of the writing signal and the determination by the indeterminate state determination unit, the mode switching unit, In the second mode, when the indeterminate state determining means determines that the frequency of the writing signal is in an indefinite state, the operation mode is changed to the second mode. And switches from over de in the third mode.

  This ensures that the user has changed from the state where the electronic writing instrument is left on the writing object to the state where the electronic writing instrument is far away from the writing object by the frequency value of the writing signal becoming indefinite. Can be identified. At this time, in the sixth invention of this application, the selection of the main coil is stopped and the auxiliary coil is selected in the second mode. Then, the frequency of the writing signal received by the selected auxiliary coil is detected, and the indeterminate state is determined. Thus, by canceling the selection of the main coil and performing reception with the auxiliary coil, it is possible to reliably realize power saving in the second mode.

In a sixth aspect based on the third or fourth aspect , the frequency of the writing signal detected by the frequency detection means based on the reception result of the writing signal by the plurality of main coils is indefinite. Therefore, the electronic writing instrument is an indeterminate state determining unit that determines that the electronic writing instrument is in a state of being separated from the main coil, and the second mode sequentially turns each main coil on a cycle longer than the predetermined cycle. The mode is a mode in which the detection of the frequency of the writing signal by the frequency detection unit and the determination by the indeterminate state determination unit are performed based on the reception result of the writing signal by the selected main coil, and the mode switching In the second mode, the means determines the operation mode when the frequency of the writing signal is in an indefinite state by the indeterminate state determination unit. And switches from the mode to the third mode.

  This ensures that the user has changed from the state where the electronic writing instrument is left on the writing object to the state where the electronic writing instrument is far away from the writing object by the frequency value of the writing signal becoming indefinite. Can be identified. At this time, in the seventh invention of the present application, in the second mode, the signal detection period of the main coil is changed to a period longer than that of the first mode. Then, the frequency of the writing signal received by the main coil selected in this long cycle is detected, and the indeterminate state is determined. Thus, by lengthening the signal detection cycle of the main coil, it is possible to reliably realize power saving in the second mode.

  According to the present invention, it is possible to reliably save power even if the user does not perform a power-off operation separately, and wasteful power consumption can be prevented.

It is an external appearance perspective view, a conceptual top view, and a conceptual side view showing the mode at the time of use of the handwriting input device provided with the coordinate detection apparatus of one embodiment of this invention. It is a notional top view showing the internal configuration of an electronic pen. It is a functional block diagram showing the functional structure of a handwriting input device. It is a notional top view showing the internal configuration of a coil sheet. It is explanatory drawing showing the positional relationship of the coil of an electronic pen, and the coil sheet | seat of a coordinate detection apparatus. It is explanatory drawing showing the case where a frequency is a fixed state and the case where it is an indefinite state. It is a flowchart showing the control procedure which CPU of a coordinate detection apparatus performs. It is a flowchart showing the control procedure which CPU of a coordinate detection apparatus performs in the modification which performs the scanning process of a sense coil part intermittently. An output voltage generated in each sense coil when the electronic pen is in the input posture state in a modification in which the posture state of the electronic pen is determined based on the output mode of the magnetic field received by the coil FIG. 6 is a graph showing a distribution of values of and a graph showing a distribution of parameter values. FIG. 5 is a graph showing a distribution of output voltage values generated in each sense coil and a graph showing a distribution of parameter values when the electronic pen is in an unattended posture. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1A, the handwriting input device 1 in the present embodiment includes an electronic pen 2 that is an electronic writing tool and a coordinate detection device 3 that is an electronic writing device. In the handwriting input device 1, the user has an electronic pen 2. The electronic pen 2 is for inputting data in accordance with writing contents on a note 30 to be described later, and functions as an input means for position information, that is, coordinate data, in addition to a function as a writing instrument.

  As shown in FIGS. 1 (a), 1 (b), and 1 (c), the coordinate detection device 3 is arranged in a predetermined direction (horizontal direction in FIG. 1 (b)) so as to substantially cover a note 30 described later. ) Has a sheet body 10 made of a plastic member having a shape that can be spread. The sheet body 10 includes a left sheet portion 10L including a left coil sheet 100L and a right sheet portion 10R including a right coil sheet 100R.

  A notebook 30 having a shape that can be spread in the predetermined direction, which is a substantially notebook-shaped writing body, is disposed so as to overlap the sheet body 10. In addition, you may provide the notebook holding | maintenance part 11 as shown to Fig.1 (a) in left sheet | seat part 10L and right sheet | seat part 10R, respectively. Thereby, the coordinate detection apparatus 3 can be integrated with the notebook 30 easily and reliably, and the handleability by the user can be improved.

  Further, as shown in FIG. 1 (c), a magnetic shield 15L and a magnetic shield 15R are provided on the back side (the lower side in FIG. 1 (c)) of the left seat portion 10L and the right seat portion 10R, respectively. . The magnetic shields 15L and 15R are made of a magnetic material having an electromagnetic wave attenuation function.

  The user writes a desired handwritten character string or the like on the left writing surface 31 </ b> L or the right writing surface 31 </ b> R of the notebook 30 using the electronic pen 2. By the movement of the electronic pen 2 corresponding to the writing operation, electronic input information corresponding to the written content, that is, a pen position data string described later is stored in the electronic file. At that time, the user operates a page switching button (not shown) by switching the page to the left writing surface 31L, the right writing surface 31R, etc. of the notebook 30 by actually operating the page switching button (not shown). Files can be saved while performing page switching (page advance or page return).

  When the user uses the handwriting input device 1, a power switch (not shown) provided in the electronic pen 2 is turned on. As shown in FIGS. 2 and 3, the electronic pen 2 is a signal generating means including a pen tip 2 a provided at the tip, a permanent magnet 45, a coil 44 that is a magnetic field application coil, and a capacitor 45. An LC oscillation circuit 41, a tip switch 42, a control unit 46 that controls the entire electronic pen 20, a control board 40 on which the capacitor 45 is disposed, and a battery 43 are included. The signal generating means including the magnetic field application coil is not limited to the oscillation circuit such as the LC oscillation circuit 41, and may be a resonance circuit.

  The tip switch 42 operates according to the contact state of the pen tip 2a with the writing surfaces 31L and 31R, and sends a command signal S0 for changing the frequency of an alternating magnetic field (described later) generated from the coil 44 to the control unit 46. It is a switch that outputs the signal. The tip switch 42 is turned on when the user presses the pen tip 2a against the writing surfaces 31L and 31R (pens down) in order to write characters or the like. In this case, a command signal S0 is output to the control unit 46. On the other hand, when the user stops writing characters or the like and separates the pen tip 2a from the writing surfaces 31L and 31R (pens up), the signal is turned off. In this case, the command signal S0 is not output to the control unit 46.

  The LC oscillation circuit 41 is a circuit for generating and outputting an alternating magnetic field (hereinafter simply referred to as “magnetic field” as appropriate), which is a writing signal for position detection. The coil 44 of the LC oscillation circuit 41 is disposed so as to be wound around the permanent magnet 45 and is electrically connected to the capacitor 45, and generates a magnetic field generated by the LC oscillation circuit 41. The frequency of the magnetic field generated from the coil 44 by the LC oscillation circuit 41 is changed by changing the capacitance of the capacitor 45 based on control by the control unit 46 according to whether the tip switch 42 is turned on or off. That is, when the tip switch 42 is on, the control unit 46 to which the command signal S0 is input controls the LC oscillation circuit 41 so as to generate a magnetic field having a specific frequency f1 from the coil 44. Thereby, the frequency of the magnetic field generated from the coil 44 becomes the specific frequency f1. On the other hand, when the tip switch 42 is OFF, the control unit 46 to which the command signal S0 is not input controls the LC oscillation circuit 41 so as to generate a magnetic field having a specific frequency f2 from the coil 44. Thereby, the frequency of the magnetic field generated from the coil 44 becomes the specific frequency f2.

  Hereinafter, as appropriate, the frequency f1 of the magnetic field generated from the coil 44 when the tip switch 42 is on is referred to as “input frequency f1”, and the frequency f2 of the magnetic field generated from the coil 44 when the tip switch 42 is off. Is referred to as “approach frequency f2”. The magnetic field generated from the coil 44 is detected by the coordinate detection device 3. Note that by setting f1> f2, it is possible to reduce the power consumption of the electronic pen 2 when the magnetic field having the approach frequency f2 is generated.

  The battery 43 supplies power to the control unit 46, the LC oscillation circuit 41, and the like when the power switch of the electronic pen 2 is turned on.

  On the other hand, as shown in FIG. 3, the coordinate detection device 3 includes coil sheets 100L and 100R, an approach detection circuit 50, a position detection circuit 60, a peripheral circuit 70, a microcomputer 80, a battery 21, and a switch unit 90. And have. The coil sheets 100L and 100R are connected to the approach detection circuit 50 and the position detection circuit 60 via signal lines. The approach detection circuit 50, the position detection circuit 60, the peripheral circuit 70, and the battery 21 are connected by a power line via the switch unit 90.

  The microcomputer 80 includes a CPU 80a, a ROM 80b, a RAM 80c, a counter 80d, a clock 80e, other A / D conversion function units, an interrupt function unit, and the like as one integrated circuit. The microcomputer 80 controls various processes executed by the coordinate detection device 3 and controls the operation states of the approach detection circuit 50, the position detection circuit 60, and the peripheral circuit 70. Details of the control contents will be described later with reference to FIG.

  For example, the microcomputer 80 includes three different operation modes included in the coordinate detection device 3, that is, a position detection mode that is the first mode, a frequency monitoring mode that is the second mode, and a voltage monitoring mode that is the third mode. Switch. Details of the position detection mode, the frequency monitoring mode, and the voltage monitoring mode, and details of switching between the position detection mode, the frequency monitoring mode, and the voltage monitoring mode will be described later.

  As shown in FIGS. 3 and 4, the coil sheets 100 </ b> L and 100 </ b> R include a sense coil unit 110 and an approach detection coil unit 120. That is, the sense coil part 110 and the proximity detection coil part 120 arranged as shown in FIG. 4 are resin-molded into, for example, a rectangular thin plate shape to constitute the coil sheets 100L and 100R.

  As shown in FIG. 4, the sense coil unit 110 includes m loop-shaped sense coils X1 to Xm arranged in the x-axis direction and n loop-shaped sense coils Y1 to Ym arranged in the y-axis direction. Yn. Note that each of the m sense coils X1 to Xm and the n sense coils Y1 to Yn constituting the sense coil unit 110 is a coil capable of receiving a magnetic field generated by the coil 44 of the electronic pen 2, This corresponds to the main coil recited in the claims. The sense coils X1 to Xm and the sense coils Y1 to Yn are arranged in a positional relationship orthogonal to each other. In addition, the coil surfaces of the sense coils X1 to Xm and Y1 to Yn are substantially parallel to the directions of the writing surfaces 31L and 31R of the notebook 30. Further, the sense coils X1 to Xm and Y1 to Yn are formed of, for example, copper wires having an insulating coating layer formed on the surface. Furthermore, the sense coils X1 to Xm and Y1 to Yn are connected to a multiplexer 62 of the position detection circuit 60 described later by a lead line not shown and described. Then, the scan process of the sense coil unit 110 is started, and the sense coils X1 to Xm and Y1 to Yn receive the magnetic field generated by the coil 44 of the electronic pen 2, in other words, the sense coils X1 to Xm and Y1. Electromotive force is generated in the sense coils X1 to Xm and Y1 to Yn due to electromagnetic induction between ~ Yn and the magnetic field generated by the coil 44. That is, the sense coils X1 to Xm and Y1 to Yn generate a signal S1 (see FIG. 3) by magnetic coupling with the coil 44.

  Each of the sense coils X1 to Xm is formed in a substantially rectangular shape including a side having a width P1 in the x-axis direction and a side having a length P2 in the y-axis direction longer than P1. Each of the sense coils X1 to Xm is arranged continuously in the x-axis direction at a predetermined constant pitch. For example, the adjacent sense coils X1 to Xm are overlapped with each other at a half pitch of P1.

  Each of the sense coils Y1 to Yn is formed in a substantially rectangular shape having a side having a width P3 in the x-axis direction and a side having a length P1 in the y-axis direction shorter than P3. Each of the sense coils Y1 to Yn is continuously arranged in the y-axis direction at a predetermined constant pitch. For example, the adjacent sense coils Y1 to Yn are overlapped at a pitch of 1/2 of P1.

  In FIG. 4, for the sake of simplicity, the sides of the sense coils X1 to Xm and the sense coils Y1 to Yn are not overlapped for convenience. Not. In FIG. 4, the shape of the sense coils X <b> 1 to Xm and Y <b> 1 to Yn is illustrated by omitting a lead line that enters a multiplexer 62 described later.

  As shown in FIG. 4, the approach detection coil unit 120 includes a single loop-shaped approach detection coil 121 different from the sense coils X1 to Xm and Y1 to Yn of the sense coil unit 110. In addition, the approach detection coil 121 which comprises the approach detection coil part 120 is a coil which can receive the magnetic field generated with the coil 44 of the electronic pen 2, and is equivalent to the auxiliary coil of each claim. In the proximity detection coil 121, the coil surface direction is substantially parallel to the direction of the writing surfaces 31L and 31R of the notebook 30. Further, the approach detection coil 121 is connected to a band pass filter 52 of the approach detection circuit 50 described later by a lead wire not shown and described. Then, the scanning process of the proximity detection coil unit 120 is started, and the proximity detection coil 121 receives the magnetic field generated by the coil 44 of the electronic pen 2, in other words, generated by the proximity detection coil 121 and the coil 44. An electromotive force is generated in the proximity detection coil 121 by electromagnetic induction with a magnetic field. That is, the approach detection coil 121 generates a signal S2 (see FIG. 3) by magnetic coupling with the coil 44.

  Returning to FIG. 3, the approach detection circuit 50 is a known circuit that detects that the electronic pen 2 has approached the coordinate detection device 3 based on the signal S <b> 2 generated by the approach detection coil 121. As shown in FIG. 3, the approach detection circuit 50 includes a band pass filter 52, an amplifier circuit 54, a switching circuit 55, a rectifier circuit 56, a voltage detection circuit 58, and a limiter 59.

  The band pass filter 52 removes an unnecessary band from the input signal S2. The band pass filter 52 passes, for example, a signal S21 having a frequency ranging from a specific frequency f3 (details will be described later) lower than the approach frequency f2 to the approach frequency f2.

  The amplifying circuit 54 amplifies the signal S21 that has passed through the bandpass filter 52 to obtain a signal S22.

  The switching circuit 55 connects the amplifier circuit 54 and one of the rectifier circuit 56 and the limiter 59 based on the output destination selection signal S27 from the microcomputer 80. When the switching circuit 55 connects the amplifier circuit 54 and the rectifier circuit 56, the signal S 28 corresponding to the signal S 22 amplified by the amplifier circuit 54 is output to the rectifier circuit 56 via the switch circuit 55. The rectifier circuit 56 performs amplitude detection of the signal S28 input from the switching circuit 55.

  The voltage detection circuit 58 prevents malfunction caused by noise or a magnetic field whose frequency value is indefinite, and removes frequency components in the range from the specific frequency f3 to the approach frequency f2. For this purpose, the voltage detection circuit 58 detects the amplitude of the signal S23 subjected to amplitude detection by the rectifier circuit 56. Thereby, the value V of the output voltage due to the magnetic field received by the proximity detection coil 121 in the scanning process of the proximity detection coil unit 120 is detected. Then, the voltage detection circuit 58 determines whether or not the amplitude of the detected signal S23 exceeds a predetermined threshold value Vth. When the electronic pen 2 approaches the coil sheets 100L and 100R (specifically, the approach detection coil 121), the amplitude of the signal S23 exceeds the threshold value Vth. When the electronic pen 2 approaches the coil sheets 100L and 100R and the voltage detection circuit 58 detects that the amplitude of the signal S23 exceeds the threshold value Vth, the release signal S24 is output to the microcomputer 80. Is done. The cancel signal S24 is a signal for canceling the voltage monitoring mode.

  On the other hand, when the switching circuit 55 connects the amplifier circuit 54 and the limiter 59, the signal S25 corresponding to the signal S22 amplified by the amplifier circuit 54 is output to the limiter 59 via the switching circuit 55. The limiter 59 processes the signal S25 input from the switching circuit 55 into a digital signal S26 having only frequency and phase information and inputs it to an interrupt input (not shown) of the microcomputer 80. The microcomputer 80 determines the frequency of the signal S2 from the approach detection coil 121 by measuring the period of the signal S26 input from the limiter 59 by a timer or the like, and stores it in the RAM 80c.

  The position detection circuit 60 is a known circuit that detects coordinates representing positions on the coil sheets 100L and 100R where the electronic pen 2 is present. As shown in FIG. 3, the position detection circuit 60 includes a multiplexer 62 (hereinafter referred to as “MUX 62” as appropriate), an amplifier circuit 64, a rectifier circuit 66, and a limiter 68.

  The MUX 62 selects the sense coils X1 to Xm and Y1 to Yn of the sense coil unit 110 one by one based on the coil selection signal S3 from the microcomputer 80. The MUX 62 receives the signal S1 generated in the selected sense coils X1 to Xm, Y1 to Yn, and outputs a corresponding signal S11 to the amplifier circuit 64.

  The amplifier circuit 64 amplifies the signal S11 input from the MUX 62. The signal S12 amplified by the amplifier circuit 64, that is, the electronic pen input detection signal S12 is input to the limiter 68. The limiter 68 processes the signal S12 input from the amplifier circuit 64 into a digital signal S15 having only frequency and phase information, and inputs it to the interrupt input of the microcomputer 80. The microcomputer 80 determines the frequency of the signal S1 from the sense coils X1 to Xm and Y1 to Yn by measuring the period of the signal S15 input from the limiter 68 with a timer or the like, and senses currently being scanned. The data is stored in the RAM 80c together with the coil numbers of the sense coils X1 to Xm and Y1 to Yn of the coil unit 110.

  Another signal S13 amplified by the amplifier circuit 64 is input to the rectifier circuit 66. The rectifier circuit 66 amplitude-detects the signal S13 input from the amplifier circuit 64, and then smoothes and converts it to a DC signal. The signal S14 subjected to amplitude detection by the rectifier circuit 66 is input to the microcomputer 80. As described above, the microcomputer 80 has an A / D conversion function, and converts the input signal S14 after amplitude detection into a digital signal. At this time, the ROM 80b of the microcomputer 80 stores a position coordinate table described later. By applying a position coordinate table to the digital signal, the microcomputer 80 coordinates data of the contact point between the electronic pen 2 and the notebook 30 (hereinafter, simply referred to as “coordinate data of the electronic pen 2” as appropriate), that is, The x coordinate in the x axis direction and the y coordinate in the y axis direction are calculated. The calculated coordinate data is stored in the flash memory 72 of the peripheral circuit 70 described later.

  Further, the microcomputer 80, based on the coil numbers of the maximum output sense coils X1 to Xm and Y1 to Yn, stored in the RAM 80c during the scan process of the sense coil unit 110, the sense coils X1 to Xm, The frequency of the signal S1 obtained from Y1 to Yn is detected. Thereby, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn represented by the coil numbers is detected. Further, the microcomputer 80 calculates the frequency value f of the magnetic field received by the proximity detection coil 121 based on the frequency of the signal S2 obtained from the proximity detection coil 121 and stored in the RAM 80c during the scan processing of the proximity detection coil unit 120. To detect. Details of the frequency detection will be described later.

  As shown in FIG. 3, the peripheral circuit 70 includes a flash memory 72, a communication interface 74, and a display unit 76.

  In the flash memory 72, an electronic file is prepared in advance, and stroke data based on a pen position data sequence described later including a plurality of coordinate data calculated by the microcomputer 80 is written and stored in the electronic file. .

  The communication interface 74 is an interface for providing stroke data based on a later-described pen position data sequence including a plurality of coordinate data stored in the flash memory 72 to an external device such as a personal computer. Specifically, the communication interface 74 is, for example, a USB interface for Universal Serial Bus (USB) connection, a memory card slot such as an SD card, or a wireless or wired network interface.

  The display unit 76 is configured by, for example, a liquid crystal display (LCD), and displays predetermined information related to the operation state of the coordinate detection device 3 such as the remaining amount of the battery 21.

  The switch unit 90 selectively connects the battery 21 to the approach detection circuit 50 or the position detection circuit 60 and the peripheral circuit 70 in accordance with the control signal Sa from the microcomputer 80.

  The battery 21 supplies power to the microcomputer 80 and the like when a power switch (not shown) provided in the coordinate detection device 3 is turned on.

(A) Method Principle of the Present Embodiment The feature of the present embodiment having the above-described configuration is that the posture of the electronic pen 2 is based on the frequency mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121. When the electronic pen 2 is determined to be in a neglected posture (described later) when the operation mode is the position detection mode, the operation mode is switched from the position detection mode to the frequency monitoring mode, and the operation is performed. When it is determined that the electronic pen 2 is in the input posture (described later) when the mode is the frequency monitoring mode, the operation mode is switched from the frequency monitoring mode to the position detection mode. That is, as described above, the coordinate detection device 3 of the present embodiment includes a position detection mode, a frequency monitoring mode, and a voltage monitoring mode.

  The position detection mode is a mode in which position information of the electronic pen 2 is acquired, that is, coordinate data is calculated. In this position detection mode, each of the sense coils X1 to Xm, Y1 to Yn is sequentially selected at a predetermined cycle, and the electronic pen 2 is selected based on the reception result of the magnetic field at the selected sense coils X1 to Xm and Y1 to Yn. Coordinate data is calculated. Further, based on the reception result of the magnetic field at the selected sense coils X1 to Xm and Y1 to Yn, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn is detected, and the detected value is detected. It is also determined whether or not the frequency value f is greater than a predetermined value fth2, and whether or not the detected frequency value f is in an indefinite state.

  That is, when the user is writing on the writing surfaces 31L and 31R using the electronic pen 2, magnetic fields generated by the electronic pen 2 are received by the sense coils X1 to Xm and Y1 to Yn. Then, based on the reception result, coordinate data of the electronic pen 2 is calculated. Thereby, a pen position data sequence including a plurality of coordinate data representing the movement locus of the electronic pen 2 corresponding to the writing operation when the user writes on the writing surfaces 31L and 31R is calculated.

  Further, when the user performs a writing operation using the electronic pen 2 as described above, the electronic pen 2 is in an input posture state in which data input corresponding to the writing contents on the writing surfaces 31L and 31R is performed. . FIG. 5A shows the positional relationship between the coil 44 of the electronic pen 2 in the input posture state and the coil sheets 100L and 100R of the coordinate detection device 3. As shown in FIG. 5A, when the electronic pen 2 is in the input posture, generally, the axial direction of the coil 44 of the electronic pen 2 and the direction of the writing surfaces 31L and 31R, that is, the coil sheet. The sense coils X1 to Xm and Y1 to Yn included in 100L and 100R and the coil surface direction of the proximity detection coil 121 intersect with each other. In such a positional relationship, the frequency value f of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 is the value when the electronic pen 2 is in the pen-down state (the tip switch 42 is on). In this case, the input frequency f1 is obtained, and the approach frequency f2 is obtained when the electronic pen 2 is in the pen-up state (when the tip switch 42 is off).

で表される関係が成り立つ。したがって、上記のような位置関係の変化により、センスコイルＸ１〜Ｘｍ，Ｙ１〜Ｙｎや接近検出コイル１２１のインダクタンスが大きくなった場合には、電子ペン２のコイル４４と、センスコイルＸ１〜Ｘｍ，Ｙ１〜Ｙｎや接近検出コイル１２１との共振周波数は小さくなる。この結果、センスコイルＸ１〜Ｘｍ，Ｙ１〜Ｙｎや接近検出コイル１２１で受信される磁界の周波数態様が変化する。すなわち、センスコイルＸ１〜Ｘｍ，Ｙ１〜Ｙｎや接近検出コイル１２１で受信される磁界の周波数の値ｆが、上記入力周波数ｆ１及び接近周波数ｆ２よりも小さい周波数、すなわち特定の周波数ｆ３となる。 On the other hand, when the user interrupts the writing operation and leaves the electronic pen 2 on the writing surfaces 31L and 31R, the electronic pen 2 is placed on the writing surfaces 31L and 31R. It will be in the state of a neglected posture. Note that when the electronic writing device is of a note cover type like the coordinate detection device 3 of the present embodiment, the writing object is in a notebook shape like the notebook 30, so the electronic writing tool is placed on the writing object. It is relatively easy to be left unattended. FIG. 5B shows a positional relationship between the coil 44 of the electronic pen 2 that is in the leaving posture and the coil sheets 100L and 100R of the coordinate detection device 3. As shown in FIG. 5 (b), when the electronic pen 2 is in an unattended posture, generally, the axial direction of the coil 44 of the electronic pen 2 and the direction of the writing surfaces 31L and 31R, that is, a coil sheet. The sense coils X1 to Xm and Y1 to Yn included in 100L and 100R and the coil surface direction of the proximity detection coil 121 are in a positional relationship that is substantially parallel. In the case of such a positional relationship, for example, the coil 44 of the electronic pen 2 is provided with a magnetic shield provided on the back side of the coil sheets 100L and 100R as compared to the positional relationship as shown in FIG. Since they are close to 15L and 15R, the inductances of the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 are increased. Here, when the resonance frequency is f0, the inductance is L, and the capacitance is C,

The relationship expressed by Therefore, when the inductance of the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 increases due to the change in the positional relationship as described above, the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, The resonance frequency with Y1 to Yn and the approach detection coil 121 becomes small. As a result, the frequency mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 changes. That is, the frequency value f of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 is a frequency smaller than the input frequency f1 and the proximity frequency f2, that is, a specific frequency f3.

  In this embodiment, paying attention to this point, when the operation mode of the coordinate detection device 3 is the position detection mode, the microcomputer 80 determines that the magnetic field is based on the reception results of the magnetic fields in the sense coils X1 to Xm and Y1 to Yn. The frequency value f is detected. Then, by determining whether the detected magnetic field frequency mode, that is, whether the frequency value f is larger than the predetermined value fth2, it is determined whether the electronic pen 2 is in the standing posture state or the input posture state. judge. At this time, if f ≦ fth2, it is determined that the electronic pen 2 is in the standing posture state, the operation mode is switched from the position detection mode to the frequency monitoring mode.

  Further, when the electronic pen 2 is in the input posture state as shown in FIG. 5A (or the neglected posture state as shown in FIG. 5B), FIG. As shown, the frequency value f of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 is in a constant state. On the other hand, the user has moved the electronic pen 2 from the input posture state (or the neglected posture state), and the electronic pen 2 is separated from the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121, that is, In some cases, the electronic pen 2 is placed far away from the writing surfaces 31L and 31R. In this case, the magnetic coupling state between the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 changes, and the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, The resonance frequency with Y1 to Yn and the approach detection coil 121 becomes indefinite. As a result, the frequency mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 changes. That is, when the electronic pen 2 is separated from the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121, as shown in FIG. 6B, the sense coils X1 to Xm, Y1 to Yn, The frequency value f of the magnetic field received by the approach detection coil 121 becomes indefinite.

  In the present embodiment, focusing on this point, when the operation mode of the coordinate detection device 3 is the position detection mode, the microcomputer 80 determines whether or not the detected frequency value f is in an indefinite state. Thus, it is determined whether or not the electronic pen 2 is in a state of being separated from the sense coils X1 to Xm and Y1 to Yn. At this time, when it is determined that the electronic pen 2 is separated from the sense coils X1 to Xm and Y1 to Yn because the frequency value f of the detected magnetic field is in an indefinite state, The operation mode is switched from the position detection mode to the voltage monitoring mode.

  On the other hand, in the frequency monitoring mode, the consumption by the coordinate detection device 3 is higher than that in the position detection mode corresponding to the case where the user interrupts the writing operation and leaves the electronic pen 2 on the writing surfaces 31L and 31R. This mode is set to reduce power. In this frequency monitoring mode, the proximity detection coil 121 is selected without selecting the sense coils X1 to Xm, Y1 to Yn, and the proximity detection coil 121 is based on the reception result of the magnetic field in the selected proximity detection coil 121. The frequency value f of the received magnetic field is detected. In addition, it is determined whether the detected frequency value f is in an indefinite state, whether the detected frequency value f is greater than a predetermined value fth2, and the like.

  That is, in this embodiment, when the operation mode of the coordinate detection device 3 is the frequency monitoring mode, the microcomputer 80 detects the frequency value f of the magnetic field based on the reception result of the magnetic field in the proximity detection coil 121. . Then, it is determined whether or not the electronic pen 2 is separated from the proximity detection coil 121 by determining whether or not the detected frequency mode of the magnetic field, that is, whether the frequency value f is in an indefinite state. At this time, if it is determined that the detected value f of the frequency f is in an indefinite state and the electronic pen 2 is in a state of being separated from the proximity detection coil 121, the operation mode is changed from the frequency monitoring mode. Switch to voltage monitoring mode. Further, the microcomputer 80 determines whether or not the electronic pen 2 has returned to the input posture state from the unattended posture state by determining whether or not the detected frequency value f is greater than the predetermined value fth2. At this time, if f> fth2, it is determined that the electronic pen 2 has returned to the input posture state, the operation mode is returned from the frequency monitoring mode to the position detection mode.

  On the other hand, in the voltage monitoring mode, the coordinate detection device 3 is more suitable than the position detection mode and the frequency monitoring mode corresponding to when the user finishes the writing operation and moves the electronic pen 2 away from the writing surfaces 31L and 31R. This mode is set to reduce power consumption. In this voltage monitoring mode, the proximity detection coil 121 is selected without selecting the sense coils X1 to Xm and Y1 to Yn, and the proximity detection coil 121 is based on the reception result of the magnetic field in the selected proximity detection coil 121. The generated output voltage value V is detected. It is also determined whether or not the detected output voltage value V is greater than the threshold value Vth.

  Here, the output voltage due to the magnetic field received by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121, that is, the value V of the output voltage generated by the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121. Generally depends on the distance between the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121. Therefore, the value V of the generated output voltage changes according to the distance between the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121. That is, as the distance between the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 is shorter, the generated output voltage value V increases. On the contrary, as the distance between the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Yn and the proximity detection coil 121 increases, the generated output voltage value V decreases. Therefore, when the electronic pen 2 is in a state far away from the writing surfaces 31L and 31R as described above, the coil 44 of the electronic pen 2, the sense coils X1 to Xm, Y1 to Yn, and the proximity detection coil. 121 does not enter the magnetic coupling state, and thus the generated output voltage value V is substantially zero.

  In the present embodiment, focusing on this point, when the operation mode of the coordinate detection device 3 is the voltage monitoring mode, the voltage detection circuit 58 receives the magnetic field received by the proximity detection coil 121 in the scanning process of the proximity detection coil unit 120. That is, it is determined whether the amplitude of the signal S23 based on the signal S2 generated by the approach detection coil 121 exceeds the threshold value Vth. At this time, when the voltage detection circuit 58 detects that the amplitude of the signal S23 exceeds the threshold value Vth, a release signal S24 is output to the microcomputer 80. The microcomputer 80 determines whether or not the value V of the output voltage generated in the proximity detection coil 121 is greater than the threshold value Vth by determining whether or not the release signal S24 is input from the voltage detection circuit 58. Thereby, it is determined whether or not the electronic pen 2 has approached the approach detection coil 121. At this time, it is determined that the electronic pen 2 is in the state of approaching the proximity detection coil 121 because the release signal S24 is input (the value V of the output voltage is greater than the threshold value Vth). In this case, the operation mode is switched from the voltage monitoring mode to the position detection mode.

(B) Control processing of this embodiment In order to implement | achieve the above functions, the content of the control processing performed by CPU80a of the coordinate detection apparatus 3 is demonstrated in order with FIG.

  In FIG. 7, the process shown in this flow is started when the user turns on the power of the coordinate detection device 3, for example. First, in step SS10, the CPU 80a sets the operation mode of the coordinate detection device 3 to the position detection mode. That is, the CPU 80a outputs a control signal Sa (see FIG. 3) to the switch unit 90 to cause the switch unit 90 to shut off the battery 21 and the approach detection circuit 50, and to connect the battery 21, the position detection circuit 60, and the peripheral circuit 70. And connect. As a result, the supply of power to the approach detection circuit 50 is interrupted, and power is supplied to the position detection circuit 60 and the peripheral circuit 70. As a result, the approach detection circuit 50 is switched to the resting state, and the position detection circuit 60 and the peripheral circuit 70 are switched to the operating state.

  Thereafter, in step SS20, the CPU 80a executes a scan process for the sense coil unit 110 provided in the coil sheets 100L and 100R. Specifically, the CPU 80a outputs a coil selection signal S3 for sequentially selecting the sense coils X1 to Xm and Y1 to Yn to the MUX 62, and sequentially selects the sense coils X1 to Xm and Y1 to Yn. Thus, a signal S1 (see FIG. 3) is generated by electromagnetic induction between the magnetic field generated by the coil 44 of the electronic pen 2 and any one of the selected sense coils X1 to Xm, Y1 to Yn. Then, the signal S1 from the sense coils X1 to Xm and Y1 to Yn selected by the MUX 62 in a state where the signal S1 is generated is input to the MUX 62. The MUX 62 outputs a signal S11 (see FIG. 3) corresponding to the input signal S1 to the amplifier circuit 64. The signal S11 input to the amplifier circuit 64 is amplified by the amplifier circuit 64, and the amplified signal S12 (see FIG. 3) is input to the limiter 68. The signal S12 input to the limiter 68 is processed into a digital signal S15 (see FIG. 3) having only frequency and phase information and input to the interrupt input of the microcomputer 80. The microcomputer 80 determines the frequency of the signal S1 from the sense coils X1 to Xm and Y1 to Yn by measuring the period of the input signal S15 with a timer or the like, and the sense coil section currently being scanned The data is stored in the RAM 80c together with the coil numbers of 110 sense coils X1 to Xm and Y1 to Yn. Further, another signal S13 (see FIG. 3) amplified by the amplifier circuit 64 is input to the rectifier circuit 66. The signal S13 input to the rectifier circuit 66 is input to the microcomputer 80 as an amplitude detected signal S14. The microcomputer 80 converts the input signal S14 into a digital signal.

  Then, the process proceeds to Step SS30, and the CPU 80a detects the frequency value f of the magnetic field based on the reception result of the magnetic field in the sense coils X1 to Xm and Y1 to Yn in the scan process executed in Step SS20. Specifically, the CPU 80a, based on the coil numbers of the maximum output sense coils X1 to Xm and Y1 to Yn stored in the RAM 80c in step SS20, sense coils X1 to Xm and Y1 to Y represented by the coil numbers. The frequency of the signal S1 obtained from Yn is detected. Thereby, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn represented by the coil numbers is detected.

  Thereafter, in step SS40, the CPU 80a determines whether the frequency value f of the magnetic field detected based on the magnetic field reception results in the sense coils X1 to Xm and Y1 to Yn in step SS30 is in an indefinite state. judge. Thereby, it is determined whether the electronic pen 2 is in a state of being separated from the sense coils X1 to Xm and Y1 to Yn. When the frequency value f detected in step SS30 is in a constant state, the electronic pen 2 is considered to be in a state of approaching the sense coils X1 to Xm, Y1 to Yn, and the determination in step SS40 is not satisfied. Then, the process proceeds to Step SS50.

  In step SS50, the CPU 80a determines whether the frequency value f of the magnetic field detected based on the magnetic field reception results in the sense coils X1 to Xm and Y1 to Yn in step SS30 is greater than a predetermined value fth1. . Accordingly, whether or not the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn is f1, that is, whether or not the electronic pen 2 is in the pen-down state in the input posture (the tip switch 42 is turned on). Determine. When f> fth1, it is considered that the electronic pen 2 is in the pen-down state in the input posture, the determination at Step SS50 is satisfied, and the routine goes to Step SS60.

  In step SS60, the CPU 80a calculates the coordinate data of the electronic pen 2 by a known appropriate method based on the reception results of the magnetic fields in the sense coils X1 to Xm and Y1 to Yn in the scan process executed in step SS20. I do. In the present embodiment, the CPU 80a calculates the coordinate data of the electronic pen 2 using a position coordinate table stored in the ROM 80b of the microcomputer 80.

  Then, the process proceeds to step SS70, and the CPU 80a generates (updates) a pen position data string D using the coordinate data of the electronic pen 2 calculated in step SS60. Specifically, the coordinate data calculated in step SS60 is added in association with the stroke number at the end of the pen position data sequence D composed of a plurality of coordinate data, and a new pen position data sequence D is obtained. If the coordinate data calculated in step SS60 is the first coordinate data, a new pen position data string D is generated from the one coordinate data. The pen position data string D generated in this way is temporarily stored in the RAM 80c. Note that stroke data corresponding to the writing on the writing surfaces 31L and 31R by the electronic pen 2 is generated by the pen position data string D corresponding to the coordinate data of the electronic pen 2. That is, the generation of the pen position data string D is equivalent to the generation of stroke data in other words. When step SS70 is completed, the process returns to step SS20, and the CPU 80a executes the scan process of the sense coil unit 110 again, and thereafter repeats the same procedure.

  On the other hand, if f ≦ fth1 in step SS50, the electronic pen 2 is not considered to be in the pen-down state in the input posture. In this case, the determination at Step SS50 is not satisfied, and the routine goes to Step SS80.

  In step SS80, the CPU 80a determines whether the frequency value f of the magnetic field detected based on the magnetic field reception results in the sense coils X1 to Xm and Y1 to Yn in step SS30 is greater than a predetermined value fth2. . Thereby, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn was f2 or f3, that is, the pen 2 is in the pen-up state in which the electronic pen 2 is in the input posture (the tip switch 42 is in the off state). ) Or in a neglected posture state. When f> fth2, the electronic pen 2 is considered to be in the pen-up state in the input posture, the determination in step SS80 is satisfied, the process returns to step SS20, and the CPU 80a performs the scan process of the sense coil unit 110. Is executed again, and the same procedure is repeated thereafter. On the other hand, if f ≦ fth2, the electronic pen 2 is considered to be in the neglected posture, and the determination in step SS80 is not satisfied, and the process proceeds to step SS90. Even when f> fth2, if the determination in step SS50 is not satisfied even after a predetermined time has elapsed, that is, if the electronic pen 2 is not considered to be in the pen-down state even after the predetermined time has elapsed, step SS90 You may make it move to.

  In step SS90, the CPU 80a switches the operation mode of the coordinate detection device 3 from the position detection mode to the frequency monitoring mode. That is, the CPU 80a outputs a control signal Sa to the switch unit 90, connects the battery 21 and the proximity detection circuit 50 to the switch unit 90, and blocks the battery 21, the position detection circuit 60, and the peripheral circuit 70. As a result, the supply of power to the position detection circuit 60 and the peripheral circuit 70 is cut off, and power is supplied only to the approach detection circuit 50. As a result, the approach detection circuit 50 is switched to the operating state, and the position detection circuit 60 and the peripheral circuit 70 are switched to the resting state. Further, the CPU 80a outputs an output destination selection signal S27 to the switching circuit 55 of the approach detection circuit 50, and connects the amplifier circuit 54 and the limiter 59 to the switching circuit 55.

  Thereafter, in step SS100, the CPU 80a executes a scan process of the proximity detection coil unit 120 provided in the coil sheets 100L and 100R. Specifically, the CPU 80a selects the approach detection coil 121. Thus, a signal S2 (see FIG. 3) is generated by electromagnetic induction between the magnetic field generated by the coil 44 of the electronic pen 2 and the selected proximity detection coil 121. The signal S <b> 2 from the approach detection coil 121 is input to the band pass filter 52. The band pass filter 52 outputs to the amplifier circuit 54 a signal S21 (see FIG. 3) from which unnecessary bands are removed from the input signal S2. The signal S21 input to the amplifier circuit 54 is amplified by the amplifier circuit 54, and the amplified signal S22 (see FIG. 3) becomes the signal S25 (see FIG. 3) via the switching circuit 55 and is input to the limiter 59. Is done. The signal S25 input to the limiter 59 is processed into a digital signal S26 (see FIG. 3) having only frequency and phase information and input to the interrupt input of the microcomputer 80. The microcomputer 80 determines the frequency of the signal S2 from the proximity detection coil 121 by measuring the period of the input signal S26 with a timer or the like, and stores it in the RAM 80c.

  Then, the process proceeds to Step SS110, and the CPU 80a detects the frequency value f of the magnetic field based on the reception result of the magnetic field in the proximity detection coil 121 in the scanning process executed in Step SS100. Specifically, the CPU 80a detects the frequency value f of the magnetic field received by the proximity detection coil 121 based on the frequency of the signal S2 obtained from the proximity detection coil 121 stored in the RAM 80c in step SS100.

  Thereafter, in step SS120, the CPU 80a determines whether or not the frequency value f of the magnetic field detected based on the magnetic field reception result in the proximity detection coil 121 in step SS110 is in an indefinite state. Thereby, it is determined whether or not the electronic pen 2 is separated from the approach detection coil 121. When the frequency value f detected in step SS110 is constant, it is considered that the electronic pen 2 is in a state of approaching the proximity detection coil 121, the determination in step SS120 is not satisfied, and the process proceeds to step SS130.

  In step SS130, the CPU 80a determines whether the frequency value f of the magnetic field detected based on the magnetic field reception result in the approach detection coil 121 in step SS110 is greater than a predetermined value fth2. Thereby, it is determined whether the frequency of the magnetic field received by the approach detection coil 121 is f1 or f2, or f3, that is, whether the electronic pen 2 is in the input posture state or in the neglected posture state. . If f ≦ fth2, the electronic pen 2 is considered to be in the neglected posture, and the determination at Step SS130 is not satisfied, and the routine goes to Step SS140.

  In step SS140, the CPU 80a waits for a predetermined time interval t1. Thereafter, the process returns to step SS100, and the CPU 80a executes the scan process of the approach detection coil unit 120 again, and thereafter repeats the same procedure. That is, in the state where the operation mode of the coordinate detection device 3 is the frequency monitoring mode, the scan processing of the proximity detection coil unit 121 is intermittently executed.

  On the other hand, if f> fth2 in step SS130, it is considered that the electronic pen 2 is in the input posture state, in other words, the electronic pen 2 is returned to the input posture state. In this case, the determination in step SS130 is satisfied, the process returns to step SS10, and the CPU 80a switches the operation mode of the coordinate detection device 3 from the frequency monitoring mode to the position detection mode, in other words, the position detection from the frequency monitoring mode. Return to the mode and repeat the same procedure.

  On the other hand, in step SS40, when the frequency value f detected in step SS30 is in an indefinite state, the electronic pen 2 is considered to be in a state of being separated from the sense coils X1 to Xm and Y1 to Yn. Then, the determination at Step SS40 is satisfied, and the routine goes to Step SS150. On the other hand, in step SS120, when the frequency value f detected in step SS110 is in an indefinite state, it is considered that the electronic pen 2 is separated from the approach detection coil 121, and step SS120. Is satisfied, and the routine goes to Step SS150.

  In step SS150, the CPU 80a switches the operation mode of the coordinate detection device 3 to the voltage monitoring mode. Specifically, when the process proceeds from step SS40 to step SS150, the position detection mode is switched to the voltage monitoring mode, and when the process proceeds from step SS120 to step SS150, the position detection mode is switched to the voltage monitoring mode. That is, the CPU 80a outputs a control signal Sa to the switch unit 90, connects the battery 21 and the proximity detection circuit 50 to the switch unit 90, and blocks the battery 21, the position detection circuit 60, and the peripheral circuit 70. As a result, the supply of power to the position detection circuit 60 and the peripheral circuit 70 is cut off, and power is supplied only to the approach detection circuit 50. As a result, the approach detection circuit 50 is switched to the operating state, and the position detection circuit 60 and the peripheral circuit 70 are switched to the resting state. Further, the CPU 80a outputs an output destination selection signal S27 to the switching circuit 55 of the approach detection circuit 50, and connects the amplifier circuit 54 and the rectifier circuit 56 to the switching circuit 55. Note that, in the voltage monitoring mode, for example, scanning processing of the sense coil unit 110 and processing with a large load such as frequency detection are not executed, so the microcomputer 80 itself is also switched to the sleep mode (standby state).

  Then, the process proceeds to step SS160, and the CPU 80a executes a scan process of the proximity detection coil unit 120 provided in the coil sheets 100L and 100R. Specifically, the CPU 80a selects the approach detection coil 121. Thereby, the signal S2 is generated by electromagnetic induction between the magnetic field generated by the coil 44 of the electronic pen 2 and the selected proximity detection coil 121. The signal S <b> 2 from the approach detection coil 121 is input to the band pass filter 52. The band pass filter 52 outputs to the amplifier circuit 54 a signal S21 from which an unnecessary band has been removed from the input signal S2. The signal S21 input to the amplifier circuit 54 is amplified by the amplifier circuit 54, and the amplified signal S22 is input to the rectifier circuit 56 through the switching circuit 55 as a signal S28 (see FIG. 3). The signal S28 input to the rectifier circuit 56 is amplitude-detected by the rectifier circuit 56, becomes a signal S23 (see FIG. 3), and is input to the voltage detection circuit 58. When the voltage detection circuit 58 detects that the amplitude of the signal S23 exceeds the threshold value Vth, a release signal S24 (see FIG. 3) is output to the microcomputer 80.

  Thereafter, in step SS170, the CPU 80a determines whether or not the release signal S24 is input from the voltage detection circuit 58, so that the output voltage due to the magnetic field received by the proximity detection coil 121 in the scan process executed in step SS160. It is determined whether or not the value V is greater than the threshold value Vth. Thereby, it is determined whether or not the electronic pen 2 has approached the approach detection coil 121. An interrupt function is used for the input detection processing of the release signal S24. When the release signal S24 is not input, that is, when the value V of the output voltage generated in the proximity detection coil 121 is equal to or less than the threshold value Vth, the electronic pen 2 is in a state of being separated from the proximity detection coil 121. Therefore, the determination at Step SS170 is not satisfied, and the routine goes to Step SS180.

  In step SS180, the CPU 80a waits for a predetermined time interval t2. Thereafter, the process returns to step SS160, and the CPU 80a executes the scan process of the approach detection coil unit 120 again, and thereafter repeats the same procedure. That is, in the state where the operation mode of the coordinate detection device 3 is the voltage monitoring mode, the scan processing of the proximity detection coil unit 120 is executed intermittently.

  On the other hand, when the release signal S24 is input in step SS170, that is, when the value V of the output voltage generated in the proximity detection coil 121 becomes larger than the threshold value Vth, the electronic pen 2 is moved to the proximity detection coil. 121 is considered to be in an approaching state. In this case, the determination in step SS170 is satisfied, and the process returns to step SS10. The CPU 80a switches the operation mode of the coordinate detection device 3 from the voltage monitoring mode to the position detection mode, and thereafter repeats the same procedure. Note that the processing shown in this flow ends, for example, when the user turns off the power of the coordinate detection device 3.

  In the above, the procedures of Step SS20 and Step SS60 function as position information acquisition means described in each claim. Further, the procedure of Step SS30 and Step SS110 functions as a frequency detection unit. Furthermore, the procedure of step SS80 and step SS130 functions as a state determination unit. Furthermore, the procedure of step SS40 and step SS120 functions as an indefinite state determination unit and also functions as a separation determination unit. Furthermore, the procedure of step SS170 functions as an approach determination unit. The procedures of Step SS10, Step SS90, and Step SS150 function as mode switching means.

  As described above, in the present embodiment, f> fth2 in the above example based on the frequency mode and output mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121. Based on whether or not the electronic pen 2 is in the state of being left standing (the state shown in FIG. 5B) or the state of the input posture (the state shown in FIG. 5A) (see FIG. 5A). (See Step SS80 and Step S130). In the state where the operation mode is the position detection mode, when it is determined that the electronic pen 2 is in the state of being left standing, particularly in the present embodiment, the magnetic field received by the sense coils X1 to Xm and Y1 to Yn. When it is determined that the electronic pen 2 is in the state of being left standing because the frequency value f is equal to or less than the predetermined value fth2, the operation mode is switched from the position detection mode to the frequency monitoring mode (see step SS90). As a result, when the user interrupts writing on the writing surfaces 31L and 31R and leaves the electronic pen 2 on the writing surfaces 31L and 31R, the neglected state is detected and frequency monitoring is performed from the position detection mode. The operation mode is switched to the mode. As a result, even if the user does not perform a power-off operation separately, it is possible to reliably save power and to prevent wasteful power consumption.

  In addition, when it is determined that the electronic pen 2 is in the input posture state in the state where the operation mode is the frequency monitoring mode, particularly in the present embodiment, the frequency value f of the magnetic field received by the proximity detection coil 121 is If it is determined that the electronic pen 2 has returned to the input posture due to being larger than the predetermined value fth2, the operation mode is returned from the frequency monitoring mode to the position detection mode (see step SS10). Thereby, when the user resumes writing on the writing surfaces 31L and 31R by holding the electronic pen 2 left on the writing surfaces 31L and 31R again, the writing restart state is detected and the frequency monitoring mode is started. The operation mode is switched to the position detection mode. As a result, the calculation of the coordinate data of the electronic pen 2 can be reliably restarted without the user performing a power-on operation separately. Moreover, calculation of the coordinate data of the electronic pen 2 does not fail due to the forgotten power-on operation. In particular, power selection in the frequency monitoring mode can be reliably realized by canceling selection of the sense coils X1 to Xm and Y1 to Yn in the frequency monitoring mode and performing reception by the proximity detection coil 121.

  In the present embodiment, in particular, the frequency value f of the magnetic field based on the reception result of the magnetic field (more specifically, the alternating magnetic field) in the sense coils X1 to Xm and Y1 to Yn or in the proximity detection coil 121. (See Step SS30 and Step SS110). When the detected frequency value f is equal to or less than the predetermined value fth2, it is determined that the electronic pen 2 is in the state of being left standing, and the detected frequency value f is greater than the predetermined value fth2. The electronic pen 2 is determined to be in the input posture state. Thereby, the state in which the user performs the writing operation with the electronic pen 2 in hand, and the state in which the user leaves the electronic pen 2 on the writing surfaces 31L and 31R, the electronic pen 2 and the sense coils X1 to Xm. , Y1 to Yn, or a change in the magnetic field frequency value f based on a change in the positional relationship with the proximity detection coil 121. As a result, the configuration can be simplified and the cost can be reduced as compared with the case where a separate detection means such as a sensor is provided to detect the state of the electronic pen 2.

  In the present embodiment, in particular, whether or not the electronic pen 2 is separated from the proximity detection coil 121 based on whether or not the frequency value f of the magnetic field received by the proximity detection coil 121 is in an indefinite state. Is determined (see step SS120). In the frequency monitoring mode, when it is determined that the electronic pen 2 is separated from the proximity detection coil 121, the operation mode is switched from the frequency monitoring mode to the voltage monitoring mode (see step SS150). Thus, when the user finishes writing on the writing surfaces 31L and 31R and moves the electronic pen 2 away from the writing surfaces 31L and 31R, the state is detected and the operation is switched from the frequency monitoring mode to the voltage monitoring mode. The mode is switched. As a result, it is possible to reliably prevent wasteful power consumption in a manner that reflects the intention of the user to end writing.

  In the present embodiment, the electronic pen 2 approaches the approach detection coil 121 based on whether or not the release signal S24 from the voltage detection circuit 58 is input to the microcomputer 80 in the state in which the voltage monitoring mode is switched. It is determined whether or not (see step SS170). When it is determined that the electronic pen 2 is in the state of approaching the proximity detection coil 121 in the state where the operation mode is the voltage monitoring mode, the operation mode is switched from the voltage monitoring mode to the position detection mode (step) (See SS10). Accordingly, it is possible to cope with a case where the user intends to newly start writing on the writing surfaces 31L and 31R from a state where writing on the writing surfaces 31L and 31R is once completed. That is, when the user brings the electronic pen 2 away from the writing surfaces 31L and 31R toward the writing surfaces 31L and 31R, the approaching state is detected and the operation mode is switched from the voltage monitoring mode to the position detection mode. It is done. As a result, the calculation of the coordinate data of the electronic pen 2 can be reliably started in a manner that reliably reflects the user's intention to start writing. In addition, the value V of the output voltage of the magnetic field is large that the user has changed the electronic pen 2 from the state far away from the writing surfaces 31L and 31R to the state in which the electronic pen 2 approaches the writing surfaces 31L and 31R again. It can be reliably identified by becoming. In the voltage monitoring mode, the selection of the sense coils X1 to Xm and Y1 to Yn is stopped, and the approach detection coil 121 is selected. Then, the value V of the output voltage of the magnetic field received by the selected approach detection coil 121 is detected, and voltage determination is performed. Thus, by canceling the selection of the sense coils X1 to Xm and Y1 to Yn and performing reception by the proximity detection coil 121, it is possible to reliably realize power saving in the voltage monitoring mode.

  In the present embodiment, in particular, the electronic pen 2 is separated from the proximity detection coil 121 because the frequency value f of the magnetic field detected based on the reception result of the magnetic field in the proximity detection coil 121 becomes indefinite. It is determined that In the frequency monitoring mode, when it is determined that the magnetic field frequency value f is in an indefinite state, the operation mode is switched from the frequency monitoring mode to the voltage monitoring mode. As a result, the value f of the magnetic field frequency is indefinite that the user has changed from the state in which the electronic pen 2 is left on the writing surfaces 31L and 31R to the state in which the electronic pen 2 is far from the writing surfaces 31L and 31R. Can be reliably identified. At this time, in the frequency monitoring mode, selection of the sense coils X1 to Xm and Y1 to Yn is stopped, and the approach detection coil 121 is selected. Then, the frequency value f of the magnetic field received by the selected approach detection coil 121 is detected, and the indefinite state is determined. Thus, by canceling the selection of the sense coils X1 to Xm and Y1 to Yn and performing reception by the proximity detection coil 121, it is possible to reliably realize power saving in the frequency monitoring mode.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and technical idea of the present invention. Hereinafter, such modifications will be sequentially described.

(1) When the scanning process of the sense coil unit is intermittently performed In the above embodiment, the scanning process of the proximity detection coil unit 120 is intermittently performed, and the magnetic field is received by the proximity detection coil 121 in the scanning process. Although the detection of the frequency of the magnetic field and the detection of the output voltage by the magnetic field are performed based on the result, the present invention is not limited thereto. That is, the scan process of the sense coil unit 110 is intermittently executed, and the detection of the magnetic field and the detection of the output voltage by the magnetic field are performed based on the reception result of the magnetic field in the sense coils X1 to Xm and Y1 to Yn in the scan process. May be performed.

  The configuration of the handwriting input device 1 in the present modification is substantially the same as the configuration of the handwriting input device 1 in the above embodiment. However, in the coordinate detection device 3 of the present modification, the position detection coil unit 120 described above is omitted. That is, in the coordinate detection device 3 of the present modification, the sense coil portions 110 arranged as shown in FIG. 4 described above are formed by resin molding, for example, in the shape of a thin plate having a rectangular outer shape, thereby forming the coil sheets 100L and 100R. Yes.

  Further, in the frequency monitoring mode in this modification, each of the sense coils X1 to Xm and Y1 to Yn is set at a predetermined cycle, that is, a cycle longer than the signal detection cycle of each of the sense coils X1 to Xm and Y1 to Yn in the position detection mode. The frequency f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn is detected based on the selection result, and the magnetic field reception results of the selected sense coils X1 to Xm and Y1 to Yn. In addition, it is determined whether the detected frequency value f is in an indefinite state, whether the detected frequency value f is greater than a predetermined value fth2, and the like.

  Furthermore, in the voltage monitoring mode in this modification, each of the sense coils X1 to Xm and Y1 to Yn is selected with a period longer than the predetermined period, and the magnetic field of the selected sense coils X1 to Xm and Y1 to Yn is selected. Based on the reception result, the value V of the output voltage generated in the sense coils X1 to Xm and Y1 to Yn is detected. It is also determined whether or not the detected output voltage value V is greater than the aforementioned threshold value Vth.

  The contents of the control process performed by the CPU 80a of the coordinate detection device 3 in this modification will be described in order with reference to FIG. FIG. 8 corresponds to FIG. 7 described above. The same steps as those in FIG.

  8 differs from FIG. 7 described above in that steps SS100 ′ to SS140 ′ and steps SS160 ′ to SS180 ′ are provided in place of steps SS100 to SS140 and steps SS160 to SS180. Is a point. That is, Step SS10 to Step SS90 are the same as those in FIG. In step SS90, when the operation mode of the coordinate detection device 3 is switched from the position detection mode to the frequency monitoring mode, the process proceeds to step SS100 ′ provided in place of step SS100.

  In step SS100 ′, the CPU 80a executes a scan process of the sense coil unit 110 provided in the coil sheets 100L and 100R. Specifically, the CPU 80a outputs a coil selection signal for sequentially selecting the sense coils X1 to Xm and Y1 to Yn to a MUX (not shown) provided in the approach detection circuit 50, and each of the sense coils X1 to Xm. , Y1 to Yn are sequentially selected. Thereby, a signal is generated by electromagnetic induction between the magnetic field generated by the coil 44 of the electronic pen 2 and any one of the selected sense coils X1 to Xm, Y1 to Yn. Then, the signals from the sense coils X1 to Xm and Y1 to Yn selected by the MUX in a state where the signal is generated are input to the MUX. The MUX outputs a signal corresponding to the input signal to the band pass filter 52. The band pass filter 52 outputs the above-described signal S21 from which unnecessary bands have been removed from the input signal to the amplifier circuit 54. The signal S21 input to the amplifier circuit 54 is amplified by the amplifier circuit 54, and the above-described signal S22 after amplification becomes the above-described signal S25 via the switching circuit 55 and is input to the limiter 59. The signal S25 input to the limiter 59 is processed into the aforementioned digital signal S26 having only frequency and phase information and input to the interrupt input of the microcomputer 80. The microcomputer 80 determines the frequency of the signals from the sense coils X1 to Xm and Y1 to Yn by measuring the period of the input signal S26 with a timer or the like, and the sense coil unit 110 currently scanning is detected. Are stored in the RAM 80c together with the coil numbers of the sense coils X1 to Xm and Y1 to Yn.

  Then, the process proceeds to Step SS110 ′ provided in place of Step SS110, and the CPU 80a determines the magnetic field based on the reception result of the magnetic field in the sense coils X1 to Xm and Y1 to Yn in the scan processing executed in Step SS100 ′. The frequency value f is detected. Specifically, the CPU 80a, based on the coil numbers of the maximum output sense coils X1 to Xm and Y1 to Yn stored in the RAM 80c in step SS110 ′, sense coils X1 to Xm and Y1 represented by the coil numbers. The frequency of the signal obtained from ~ Yn is detected. Thereby, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn represented by the coil numbers is detected.

  Thereafter, in step SS120 ′ provided in place of step SS120, the CPU 80a obtains the frequency value f of the magnetic field detected based on the magnetic field reception results in the sense coils X1 to Xm and Y1 to Yn in step SS110 ′. It is determined whether the state is indefinite. Thereby, it is determined whether the electronic pen 2 is in a state of being separated from the sense coils X1 to Xm and Y1 to Yn. If the frequency value f detected in step SS110 ′ is in a constant state, the electronic pen 2 is considered to be in a state of approaching the sense coils X1 to Xm, Y1 to Yn, and the determination in step SS120 ′ is performed. If not satisfied, the process proceeds to step SS130 ′ provided in place of step SS130.

  In step SS130 ′, the CPU 80a determines whether the frequency value f of the magnetic field detected based on the magnetic field reception results in the sense coils X1 to Xm and Y1 to Yn in step SS110 ′ is greater than a predetermined value fth2. judge. Accordingly, whether the frequency of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn is f1 or f2, or f3, that is, the electronic pen 2 is in the input posture or in the state of being left. Determine if there is. If f ≦ fth2, the electronic pen 2 is considered to be in the neglected posture, and the determination in step SS130 ′ is not satisfied, and the process proceeds to step SS140 ′ provided in place of step SS140.

  In step SS140 ′, the CPU 80a waits for a predetermined time interval t3. Thereafter, the process returns to step SS100 ′, and the CPU 80a executes the scan process of the sense coil unit 110 again, and thereafter repeats the same procedure. That is, when the operation mode of the coordinate detection device 3 is the frequency monitoring mode, the scan processing of the sense coil unit 110 is intermittently executed. In other words, the sense coils X1 to Xm and Y1 to Yn are sequentially selected in a cycle longer than the signal detection cycle of the sense coils X1 to Xm and Y1 to Yn in the position detection mode.

  On the other hand, if f> fth2 in step SS130 ′, the electronic pen 2 is considered to be in the input posture state. In this case, the determination in step SS130 ′ is satisfied, and the process returns to step SS10. The CPU 80a switches the operation mode of the coordinate detection device 3 from the frequency monitoring mode to the position detection mode, and thereafter repeats the same procedure. .

  On the other hand, in step SS120 ′, when the frequency value f detected in step SS110 ′ is in an indefinite state, the electronic pen 2 is in a state of being separated from the sense coils X1 to Xm and Y1 to Yn. Therefore, the determination at Step SS120 ′ is satisfied, and the routine goes to Step SS150.

  Step SS150 is the same as that in FIG. 7 described above, and switches the operation mode of the coordinate detection device 3 to the voltage monitoring mode. Thereafter, the process proceeds to step SS160 ′ provided in place of step SS160.

  In step SS160 ′, the CPU 80a executes a scan process of the sense coil unit 110 provided in the coil sheets 100L and 100R. Specifically, the CPU 80a outputs a coil selection signal for sequentially selecting the sense coils X1 to Xm and Y1 to Yn to the MUX provided in the proximity detection circuit 50, and outputs each of the sense coils X1 to Xm and Y1 to Yn. Let them be selected sequentially. As a result, the aforementioned signal is generated by electromagnetic induction between the magnetic field generated by the coil 44 of the electronic pen 2 and any one of the selected sense coils X1 to Xm, Y1 to Yn. Then, the signals from the sense coils X1 to Xm and Y1 to Yn selected by the MUX in a state where the signal is generated are input to the MUX. The MUX outputs a signal corresponding to the input signal to the band pass filter 52. The band pass filter 52 outputs the above-described signal S21 from which unnecessary bands have been removed from the input signal to the amplifier circuit 54. The signal S21 input to the amplifier circuit 54 is amplified by the amplifier circuit 54, and the amplified signal S22 is input to the rectifier circuit 56 through the switching circuit 55 as the signal S28. The signal S28 input to the rectifier circuit 56 is amplitude-detected by the rectifier circuit 56 to be the signal S23 described above and input to the voltage detection circuit 58. When the voltage detection circuit 58 detects that the amplitude of the signal S23 exceeds the threshold value Vth, the release signal S24 is output to the microcomputer 80.

  Thereafter, in step SS170 ′ provided in place of step SS170, the CPU 80a determines whether or not the release signal S24 is input from the voltage detection circuit 58, whereby the sense coil X1 is detected in the scan process executed in step SS160 ′. It is determined whether or not the value V of the output voltage due to the magnetic field received at .about.Xm, Y1 to Yn is greater than the threshold value Vth. Thereby, it is determined whether the electronic pen 2 has approached the sense coils X1 to Xm and Y1 to Yn. An interrupt function is used for the input detection processing of the release signal S24. When the release signal S24 is not input, that is, when the value V of the output voltage generated in the sense coils X1 to Xm and Y1 to Yn is equal to or lower than the threshold value Vth, the electronic pen 2 is connected to the sense coils X1 to Xm. , Y1 to Yn are considered to be in a separated state, the determination in step SS170 ′ is not satisfied, and the process proceeds to step SS180 ′ provided in place of step SS180.

  In step SS180 ′, the CPU 80a waits for a predetermined time interval t4. Thereafter, the process returns to step SS160 ′, and the CPU 80a executes the scan process of the sense coil unit 110 again, and thereafter repeats the same procedure. That is, in the state where the operation mode of the coordinate detection device 3 is the voltage monitoring mode, the scan processing of the sense coil unit 110 is intermittently executed. In other words, the sense coils X1 to Xm and Y1 to Yn are sequentially selected in a cycle longer than the signal detection cycle of the sense coils X1 to Xm and Y1 to Yn in the position detection mode.

  On the other hand, when the release signal S24 is input in step SS170 ′, that is, when the value V of the output voltage generated in the sense coils X1 to Xm and Y1 to Yn becomes larger than the threshold value Vth, The pen 2 is considered to be in a state of being close to the sense coils X1 to Xm and Y1 to Yn. In this case, the determination in step SS170 ′ is satisfied, and the process returns to the above-described step SS10. The CPU 80a switches the operation mode of the coordinate detection device 3 from the voltage monitoring mode to the position detection mode, and thereafter repeats the same procedure. .

  In the above, the procedure of Step SS30 and Step SS110 ′ functions as a frequency detection means. Further, the procedure of Step SS80 and Step SS130 ′ functions as a state determination unit. Furthermore, the procedure of step SS40 and step SS120 ′ functions as an indefinite state determination unit and also functions as a separation determination unit. Furthermore, the procedure of step SS170 ′ functions as an approach determination unit.

  In the present modification described above, the electronic pen 2 is connected to the sense coil when the frequency value f of the magnetic field detected based on the magnetic field reception results of the sense coils X1 to Xm and Y1 to Yn is indefinite. It determines with it being in the state spaced apart from X1-Xm and Y1-Yn. In the frequency monitoring mode, when it is determined that the magnetic field frequency value f is in an indefinite state, the operation mode is switched from the frequency monitoring mode to the voltage monitoring mode. As a result, as in the above embodiment, the fact that the user changed the electronic pen 2 from being left on the writing surfaces 31L and 31R to being in a state of being far away from the writing surfaces 31L and 31R. The frequency value f becomes indefinite and can be reliably identified. At this time, in the frequency monitoring mode, the signal detection periods of the sense coils X1 to Xm and Y1 to Yn are changed to a period longer than that of the position detection mode. Then, the frequency value f of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn selected in this long cycle is detected, and the indefinite state is determined. Thus, by lengthening the signal detection cycle of the sense coils X1 to Xm and Y1 to Yn, it is possible to reliably realize power saving in the frequency monitoring mode.

  In particular, according to the present modification, the magnetic field changes from the state in which the user places the electronic pen 2 far away from the writing surfaces 31L and 31R to the state in which the electronic pen 2 approaches the writing surfaces 31L and 31R again. Can be reliably identified by the increase in the output voltage value V. At this time, in the voltage monitoring mode, the signal detection cycle of the sense coils X1 to Xm and Y1 to Yn is changed to a cycle longer than that of the position detection mode. Then, the value V of the output voltage of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn selected in this long cycle is detected, and voltage determination is performed. Thus, by extending the signal detection cycle of the sense coils X1 to Xm and Y1 to Yn, it is possible to reliably realize power saving in the voltage monitoring mode.

(2) When determining the posture state of the electronic pen based on the output mode of the magnetic field received by the coil In the above, the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121 Although the determination of the posture state of the electronic pen 2 is performed based on the frequency mode, the present invention is not limited to this. That is, the posture state of the electronic pen 2 may be determined based on the output mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121.

  FIG. 9A shows output voltage values V generated in the sense coils X1 to Xm and Y1 to Yn by the magnetic field generated from the coil 44 of the electronic pen 2 in the above-described input posture state. Represents the distribution of. In the example shown in FIG. 9A, the distribution of the output voltages V1, V2, V3, and V4 of four sense coils among the m sense coils X1 to Xm arranged in the x-axis direction is shown. Yes. FIG. 9B shows the distribution of the value of the parameter k in the range where the output voltage of the sense coil closest to the position of the electronic pen 2 in the input posture is the peak voltage.

  As shown in FIG. 9A, when the electronic pen 2 is in the input posture state, as described above, the axial direction of the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Y1. The coil surface direction of Yn intersects. In the case of such a positional relationship, the output voltage value V generated in each of the sense coils X1 to Xm and Y1 to Yn peaks the output voltage value V in the sense coil closest to the position of the electronic pen 2. As symmetric in the x-axis direction (or y-axis direction). When the electronic pen 2 is in the input posture, the output voltage V1 of the sense coil adjacent to the sense coil closest to the position of the electronic pen 2, in this example, the sense coil whose output voltage is the peak voltage V2. , V3, in this example, the output voltage V1 and the output voltage V4 of the sense coil adjacent to the sense coil having the peak voltage V2 (specifically, adjacent to the sense coil having the output voltage V3) Are relatively small values. Therefore, as shown in FIG. 9B, when the electronic pen 2 is in the input posture state, the value of the parameter k in the range where the output voltage V2 becomes the peak voltage is higher than the predetermined threshold value kth. growing. The parameter k at this time is k = V2 / V4.

  FIG. 10A shows the output voltage value V generated in each of the sense coils X1 to Xm and Y1 to Yn by the magnetic field generated from the coil 44 of the electronic pen 2 that is in the state of being left as described above. Represents the distribution of. In the example shown in FIG. 10A, among the m sense coils X1 to Xm arranged in the x-axis direction, the output voltages V1 ′ and V2 of the same four sense coils as in FIG. ', V3', V4 'distribution. FIG. 10B shows the distribution of the value of the parameter k in the range where the output voltage of the sense coil closest to the position of the electronic pen 2 in the standing posture is the peak voltage.

  As shown in FIG. 10 (a), when the electronic pen 2 is in the leaving position, as described above, the axial direction of the coil 44 of the electronic pen 2 and the sense coils X1 to Xm, Y1 to Y1. The coil surface direction of Yn is a substantially parallel positional relationship. In the case of such a positional relationship, the value V of the output voltage generated in each of the sense coils X1 to Xm, Y1 to Yn is asymmetric in the x-axis direction (or y-axis direction) and has a specific voltage distribution. . That is, the sensing coils X1 to Xm and Y1 to Yn receive the input posture in which the writing operation is performed and the leaving posture in which the electronic pen 2 is placed due to the change in the positional relationship as described above. The direction of the magnetic flux to be changed changes, and the output mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn changes. That is, the value V of the output voltage generated by the sense coils X1 to Xm and Y1 to Yn changes. When the electronic pen 2 is in an unattended posture, it is close to the sense coil closest to the position of the electronic pen 2, in this example, the sense coil whose output voltage is the peak voltage V2 ′ (specifically, The output voltage V4 'of the sense coil (adjacent to the sense coil whose output voltage is V3') is not a relatively small value. Therefore, as shown in FIG. 10 (b), when the electronic pen 2 is in an unattended posture, the value of the parameter k in the range where the output voltage V2 ′ is the peak voltage is as shown in FIG. 9 (b). The value is smaller than the value of the parameter k when the electronic pen 2 shown is in the input posture, and is equal to or less than the threshold value kth. The parameter k at this time is k = V2 ′ / V4 ′. Similarly, the value of the parameter k is equal to or less than the threshold value kth even when the orientation of the leaving posture is opposite.

  In this modification, focusing on this point, the microcomputer 80 determines whether the output mode of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn, that is, the value of the parameter k is larger than the threshold value kth, or the parameter It is determined whether the value of k is equal to or less than the threshold value kth. As a result, it is determined whether the electronic pen 2 is in the neglected posture or in the input posture. When k> kth, it is determined that the electronic pen 2 is in the input posture state. If k ≦ kth, it is determined that the electronic pen 2 is in the neglected posture. In other words, in this modification, the state of the posture of the electronic pen 2 is determined in this way, and the operation mode is switched according to the result of this determination. Also in this case, the same effects as those of the above embodiment and the modified example (1) are obtained. In the above example, the state of the posture of the electronic pen 2 is determined based on the ratio of the output voltage between the sense coil having a peak output voltage and the sense coil adjacent to the sense coil. However, the present invention is not limited to this. You may make it perform the said determination with another method.

  It should be noted that other output modes of the magnetic field received by the sense coils X1 to Xm and Y1 to Yn, for example, whether the peak width of the value V of the output voltage generated by the sense coils X1 to Xm and Y1 to Yn is wide or narrow. Alternatively, the electronic pen 2 is in the state of being left or in the state of the input posture by determining the spread of the entire distribution of the value V of the output voltage generated by the sense coils X1 to Xm and Y1 to Yn. You may make it determine whether it exists in. Further, whether or not the electronic pen 2 is separated from the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121 is determined based on the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121. You may make it perform based on an output mode. In these cases, the same effect is obtained.

(3) Others In the above embodiment and the modification of (1), it is determined whether or not the electronic pen 2 has approached the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121. Although it performed based on the output aspect of the magnetic field received by Xm, Y1-Yn, or the approach detection coil 121, it is not restricted to this. That is, the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121 is used to determine whether or not the electronic pen 2 has approached the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121. You may make it carry out based on this frequency aspect. In this case, the same effect is obtained.

  Further, in the above, based on the frequency mode and output mode of the magnetic field received by the sense coils X1 to Xm, Y1 to Yn or the proximity detection coil 121, the electronic pen 2 is in a neglected posture state or an input posture state. However, the present invention is not limited to this. That is, for example, the posture state of the electronic pen 2 is detected by an acceleration sensor, and based on the detection result, it is determined whether the electronic pen 2 is in an unattended posture state or an input posture state. Good. In this case, the same effect is obtained.

  Further, in the above, the electronic pen 2 includes the battery 43 as a self-power source, the magnetic field generated from the coil 44 by the electromotive force of the battery 43 is received by the sense coils X1 to Xm, Y1 to Yn, and the electronic pen 2 Although the coordinate data of the contact point with the notebook 30 is calculated, the present invention is not limited to this. That is, the self-power supply is not provided on the electronic pen side, the electromotive force is induced in the resonance circuit of the electronic pen by magnetic induction from the coil on the device side, and the electric charge is accumulated in the capacitor of the electronic pen. The magnetic field generated by the electronic pen may be received by a coil on the apparatus side, and the position coordinates of the contact point between the electronic pen and the notebook 30 may be acquired. In this case, the same effect is obtained.

  Further, in the above, the position information of the contact point between the electronic pen 2 and the notebook 30 is acquired by the non-contact method in which the sense coil unit 110 provided on the sheet body 10 transmits and receives electromagnetic waves to and from the electronic pen 2. Not limited. That is, the contact between the pen and the notebook 30 by a contact method in which the movement of the pen is detected by the tablet sheet when a writing operation such as a character string is performed on the tablet sheet by using a method other than the above. You may acquire the positional information on a point. In this case, the same effect is obtained.

  In addition, in the above, the arrow shown in FIG. 3 shows an example of the signal flow, and does not limit the signal flow direction.

  The flowcharts shown in FIGS. 7 and 8 are not intended to limit the present invention to the procedure shown in the above flow, but to add or delete procedures or change the order within the scope not departing from the spirit and technical idea of the invention. May be.

  In addition to those already described above, the methods according to the above-described embodiments and modifications may be used in appropriate combination.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 Handwriting input device 2 Electronic pen (electronic writing instrument)
3 Coordinate detection device (electronic writing device)
30 notes (written cursive)
41 LC oscillation circuit (signal generation means)
44 Coil (Magnetic field application coil)
80a CPU
121 Approach detection coil (auxiliary coil)
X1 to Xm Sense coil (main coil)
Y1-Yn Sense coil (main coil)

Claims (6)

A signal generating means having a coil for applying a magnetic field, and receiving a writing signal for position detection generated and output by the signal generating means of an electronic writing instrument for inputting data corresponding to the writing content to the writing object. A plurality of possible main coils, position information acquisition means for acquiring position information of the electronic writing instrument based on a reception result of the writing signal at the plurality of main coils, and the plurality of main coils received by the plurality of main coils Based on the frequency mode or output mode of the writing signal, the electronic writing instrument is in a state of being left on the writing object or in an input posture for inputting data corresponding to the writing content. State determination means for determining whether or not each of the main coils is sequentially selected at a predetermined cycle, and the electronic brush by the position information acquisition means is based on the reception result of the writing signal at the selected main coil. An electronic device comprising: a first mode in which the position information of the tool is acquired; and a second mode that is an operation mode different from the first mode and is set to consume less power than the first mode. A writing device,
Frequency detection means for detecting the frequency of the writing signal on the basis of the reception result of the writing signal in the auxiliary coil different from the main coil and capable of receiving the writing signal by the main coil. And
The state determination means includes
When the frequency of the writing signal detected by the frequency detection means is equal to or lower than a predetermined value, it is determined that the electronic writing instrument is in the state of being left unattended, and the writing signal detected by the frequency detection means When the frequency is greater than a predetermined value, the electronic writing instrument is determined to be in the input posture state,
When the operation mode is the first mode and the state determination unit determines that the electronic writing instrument is in the neglected posture, the operation mode is switched from the first mode to the second mode, A mode in which the operation mode is switched from the second mode to the first mode when the state determination means determines that the electronic writing instrument is in the input posture state when the operation mode is the second mode. An electronic writing apparatus comprising switching means. The electronic writing device according to claim 1 ,
The first mode is:
Each of the main coils is sequentially selected, and based on the reception result of the writing signal in the selected main coil, a mode in which the frequency of the writing signal is detected by the frequency detection unit,
The second mode is:
In this mode, the auxiliary coil is selected without selecting the main coil, and the frequency of the writing signal is detected by the frequency detecting means based on the reception result of the writing signal at the selected auxiliary coil. ,
The mode determination means includes
In the state where the operation mode is the first mode, when the frequency of the writing signal received by the main coil detected by the frequency detection unit is equal to or lower than the predetermined value, the state determination unit performs the electronic writing instrument. Is detected by the frequency detection means when the operation mode is the second mode, the operation mode is switched from the first mode to the second mode. When the frequency of the writing signal received by the auxiliary coil is greater than the predetermined value, and the state determination means determines that the electronic writing instrument has returned to the input posture, the operation mode is set. An electronic writing apparatus that returns from the second mode to the first mode. In the electronic writing device according to claim 1 or 2 ,
A third mode which is an operation mode different from the first mode and the second mode, and is set to consume less power than the first mode and the second mode;
Based on the frequency mode or output mode of the written signal received by the plurality of main coils or an auxiliary coil different from the main coil in the state switched to the second mode, the main coil or the auxiliary Further comprising separation determining means for determining whether or not the electronic writing instrument is separated from the coil;
The mode switching means is
In the state where the operation mode is the second mode, when the electronic writing instrument is determined to be separated from the main coil or the auxiliary coil by the separation determination unit, the operation mode is changed from the second mode. An electronic writing device, wherein the electronic writing device is switched to the third mode. The electronic writing device according to claim 3 ,
The electronic writing instrument approaches the main coil or the auxiliary coil based on the frequency mode or output mode of the writing signal received by the plurality of main coils or the auxiliary coil in the state switched to the third mode. It further has an approach determination means for determining whether or not
The mode switching means is
In a state where the operation mode is the third mode, when the approach determination means determines that the electronic writing instrument is in a state of approaching the main coil or the auxiliary coil, the operation mode is set to the third mode. The electronic writing apparatus is switched from the first mode to the first mode. In the electronic writing device according to claim 3 or claim 4 ,
The separation determination means includes
The frequency detection means determines that the electronic writing instrument is in a state of being separated from the auxiliary coil because the frequency of the writing signal detected based on the reception result of the writing signal in the auxiliary coil is in an indefinite state. An indeterminate state determination means,
The second mode is:
The auxiliary coil is selected without selecting the main coil, and based on the reception result of the writing signal at the selected auxiliary coil, the frequency detection means detects the frequency of the writing signal and the indeterminate state determination means. It is a mode in which the determination by
The mode switching means is
In the second mode, the operation mode is switched from the second mode to the third mode when the frequency of the writing signal is determined to be in an indeterminate state by the indeterminate state determination unit. Electronic writing device. In the electronic writing device according to claim 3 or claim 4 ,
The separation determination means includes
It is determined that the electronic writing instrument is in a state of being separated from the main coil when the frequency of the writing signal detected based on the result of reception of the writing signal by the plurality of main coils is in an indefinite state. Is an indeterminate state determination means,
The second mode is:
Each main coil is sequentially selected at a period longer than the predetermined period, and based on the reception result of the writing signal at the selected main coil, the frequency detection means detects the frequency of the writing signal and determines the indefinite state It is a mode in which determination by means is performed,
The mode switching means is
In the second mode, the operation mode is switched from the second mode to the third mode when the frequency of the writing signal is determined to be in an indeterminate state by the indeterminate state determination unit. Electronic writing device.

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