Electronic Pen and Handwriting Input Device

Abstract

A handwriting input device that provides an electronic pen with a simple structure and can be configured at low cost. The handwriting input device includes: a position detection device unit in which a position detection sensor using an electromagnetic induction method is disposed overlapping a magnetic sheet whose color changes at a position where a magnetic pole approaches or contacts, below the magnetic sheet; and an electronic pen. The electronic pen includes: a coil; a magnetic core around which the coil is wound and having a through hole in the axial direction; a capacitor that forms a resonant circuit with the coil; and a core body that is inserted through the through hole of the magnetic core. The core body has magnetic poles at the tip portion and the tail end portion on the side opposite to the tip portion. The tip portion is configured to protrude outward from the opening of the housing of the electronic pen and is located at a position away from the tip-side end portion in the axial direction of the magnetic core. A signal having a frequency corresponding to the resonant frequency of the resonant circuit is exchanged between the position detection sensor of the position detection device unit and the resonant circuit of the electronic pen by electromagnetic induction coupling.

Description

Technical Field

[0001] The present invention relates to a handwriting input device and an electronic pen constituting the handwriting input device. Background Art

[0002] With the requirement of paperless, "replacing handwriting input using note tools such as ballpoint pens and pencils on paper, and using an electronic pen to input to an input device such as a tablet terminal having a position detection device unit equipped with a position detection sensor for detecting the indicated position of the electronic pen, so as to store the input handwriting information as electronic data" has become common.

[0003] In this case, it is required that the handwriting information input by the electronic pen can be visually confirmed by the user. Therefore, in a tablet terminal, a display panel is disposed overlapping the position detection sensor, and a display control circuit is provided. The display control circuit controls so as to confirm and display a display image (such as a note track) corresponding to the coordinate data of the indicated position of the electronic pen detected by the position detection device unit on the display panel.

[0004] In this case, as the display panel, in addition to using an LCD (Liquid Crystal Display) or an organic EL (Electroluminescence) display, electronic paper such as an electrophoretic display panel described in Patent Document 1 (Japanese Patent Laid-Open No. 2007-206845) and Patent Document 2 (Japanese Patent Laid-Open No. 2007-206846) is also used.

[0005] However, a tablet terminal as described above needs to provide a display panel and a display control circuit for displaying handwriting note information based on the coordinate information of the indicated position of the electronic pen detected by the position detection device unit, so there is a problem of high cost.

[0006] On the other hand, for example, in Patent Document 3 (Japanese Patent Laid-Open No. 2018-37033), the following handwriting input device is proposed: The handwriting input device is composed of a board device and an electronic pen. The board device is configured to be able to clamp a sheet of paper in a plate-shaped board having a position detection device unit equipped with a position detection sensor inside in a manner overlapping the position detection sensor. The electronic pen has a note tool function such as a ballpoint pen function and exchanges signals with the position detection sensor.

[0007] In this handwriting input device, if handwriting input is performed on the paper using the note tool function of the electronic pen, the coordinate information of the note track of the handwriting input is detected by the position detection device unit through the position detection sensor, and the detected coordinate information is output to, for example, a personal computer or stored in an internal memory unit for use.

[0008] According to this handwriting input device, since the note track handwritten using the note tool function of the electronic pen is depicted on the paper, the display panel for confirming and displaying the handwritten information as described above becomes unnecessary, which can reduce costs and is very convenient.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-206845

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-206846

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2018-37033 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] However, in the handwriting input device of Patent Document 3, the electronic pen needs to have functions of note tools such as a ballpoint pen function, and there is a problem that the structure of the electronic pen is complicated and the cost is high. In addition, although it is convenient for the use of storing the paper on which the handwritten note traces are formed, in the case of uses where the storage of the paper is not required, the note traces written on the paper by the ballpoint pen function or the like are not easily erased physically, so the replacement of the paper is appropriately required, which is troublesome. In addition, even if the note traces on the paper can be erased with an eraser, there is also a problem that eraser debris will be generated.

[0016] An object of the present invention is to provide an electronic pen and a handwriting input device that can solve the above problems.

[0017] Means for Solving the Problems

[0018] To solve the above problems, there is provided an electronic pen including:

[0019] a coil;

[0020] a magnetic core around which the coil is wound and having a through hole in the axial direction;

[0021] a capacitor that forms a resonant circuit with the coil; and

[0022] a core body inserted through the through hole of the magnetic core,

[0023] a signal having a frequency corresponding to the resonance frequency of the resonant circuit is coupled by electromagnetic induction between the electronic pen and a position detection sensor,

[0024] characterized in that

[0025] The core has magnetic poles at the tip part and the tail end part on the side opposite to the tip part, and the tip part is configured to protrude outward from the opening of the housing of the electronic pen and be at a position away from the end on the tip side in the axial direction of the magnetic core.

[0026] In addition, a handwriting input device is provided, comprising:

[0027] A position detection device unit, in which a position detection sensor of an electromagnetic induction method is disposed overlapping with the magnetic sheet below the magnetic sheet whose color changes at a position where a magnetic pole approaches or contacts; and

[0028] An electronic pen,

[0029] characterized in that

[0030] The electronic pen includes:

[0031] A coil;

[0032] A magnetic core around which the coil is wound and having a through hole in the axial direction;

[0033] A capacitor that forms a resonant circuit with the coil; and

[0034] A core that is inserted through the through hole of the magnetic core,

[0035] The core has magnetic poles at the tip part and the tail end part on the side opposite to the tip part, and the tip part is configured to protrude outward from the opening of the housing of the electronic pen and be at a position away from the end on the tip side in the axial direction of the magnetic core,

[0036] A signal having a frequency corresponding to the resonance frequency of the resonance circuit is exchanged between the position detection sensor of the position detection device unit and the resonance circuit of the electronic pen by electromagnetic induction coupling.

[0037] The electronic pen with the above structure is configured as follows: in an electromagnetic induction type electronic pen having a resonance circuit composed of a coil and a capacitor, the core inserted through the through hole of the magnetic core around which the coil is wound has magnetic poles at both ends in its axial direction, i.e., the tip part and the tail end part. That is, the electronic pen with the above structure can be constituted only by making the core of the electromagnetic induction type electronic pen have magnetic poles at both ends, and does not require a special structure such as a note-writing tool functional part as in Patent Document 3.

[0038] Moreover, the handwriting input device is constituted by including the electronic pen with the above structure and the position detection device unit, and the position detection device unit is provided with a position detection sensor of an electromagnetic induction method disposed overlapping with a magnetic sheet member below the magnetic sheet whose color changes at a position where a magnetic pole approaches or contacts.

[0039] In the above-described handwriting input device having the above structure, if the tip of the core of the electronic pen approaches or contacts the magnetic sheet, then due to the magnetic pole of the tip of the core, the color at the position on the magnetic sheet where the tip of the core of the electronic pen approaches or contacts changes. Thus, the movement trajectory of the tip of the core of the electronic pen appears as a writing trace on the surface of the magnetic sheet.

[0040] At the same time, signals are transmitted and received between the resonance circuit of the electronic pen and the position detection sensor by electromagnetic induction coupling. In the position detection device section, the movement trajectory of the tip of the core of the electronic pen is detected as coordinate data of the writing trace. That is, the movement trajectory of the tip of the core of the electronic pen on the surface of the magnetic sheet is represented by a color change on the surface of the magnetic sheet, and the coordinate data of this movement trajectory is detected by the position detection device section.

[0041] In the above-described handwriting input device having the above structure, by using a magnetic sheet whose color changes at the position where the magnetic poles approach or contact, it is possible to do without the paper as in the handwriting input device described in Patent Document 3. It should be noted that in such a magnetic sheet, a dedicated eraser is prepared, and it is possible to easily erase the portion of the color that has changed due to the approach or contact of the magnetic poles by using this eraser to restore it to the original color. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 FIG. is a view showing the appearance of a tablet terminal that constitutes an embodiment of the handwriting input device of the present invention.

[0043] Figure 2 FIG. is a view showing an example of the structure of a main part of an embodiment of the handwriting input device of the present invention.

[0044] Figure 3 FIG. is a view for explaining an example of the structure of a main part of an embodiment of the handwriting input device of the present invention.

[0045] Figure 4 FIG. is a view for explaining an example of the structure of a main part of an electronic pen that constitutes an embodiment of the handwriting input device of the present invention.

[0046] Figure 5 FIG. is a view for explaining an example of the structure of a main part of an electronic pen that constitutes an embodiment of the handwriting input device of the present invention.

[0047] Figure 6 FIG. is a view for explaining an example of the structure of a main part of an embodiment of the handwriting input device of the present invention.

[0048] Figure 7 FIG. is a block diagram showing an example of the structure of an electronic circuit of an embodiment of the handwriting input device of the present invention.

[0049] Figure 8 This is a diagram for explaining another structural example of the core of the electronic pen for the embodiment of the handwriting input device constituting the present invention. Specific Embodiments

[0050] [Appearance and Basic Structure of the Embodiment of the Handwriting Input Device]

[0051] Figure 1 This is a diagram for explaining the appearance of the embodiment of the handwriting input device of the present invention. In this embodiment, the handwriting input device is composed of a tablet terminal 1 and an electronic pen 2.

[0052] [Structural Example of the Tablet Terminal 1]

[0053] The tablet terminal 1 of this embodiment has a structure of a thin rectangular plate-like body with a thickness of, for example, several millimeters. One plane of the plate-like body is set as the surface, and most of the area of this surface is set as the handwriting input area (instruction input area) of the electronic pen 2. And, the surface of this handwriting input area is set as the handwriting input surface (instruction input surface) 1A. Figure 1 This is a diagram when observing the handwriting input surface 1A of the tablet terminal 1 from directly above and orthogonal to this handwriting input surface 1A.

[0054] In this embodiment, on the surface of the tablet terminal 1, an operation panel unit 1B is provided in the area above the handwriting input area. Operation buttons such as a power button 1Ba, a note input end button 1Bb, and an information sending button 1Bc, and display indicators such as a power indicator 1Bd and a communication indicator 1Be are arranged on this operation panel unit 1B. The display indicators 1Bd and 1Be are composed of, for example, LEDs (Light Emitting Diodes).

[0055] Although not shown in the figure, the tablet terminal 1 of this embodiment has a rechargeable storage battery. When the power button 1Ba is turned on, a driving voltage is supplied from the storage battery to the necessary circuit components. In addition, as will be described later, the note input end button 1Bb is pressed when the user saves the handwriting input data in page units to the storage unit. In addition, as will be described later, the tablet terminal 1 of this embodiment has a wireless communication unit. When the information sending button 1Bc is pressed, the stored handwriting input data in page units is sent to a server device composed of an external computer.

[0056] The power indicator 1Bd is for reporting the power-on state. The communication indicator 1Be is for reporting the state of sending the handwriting input data from the tablet terminal 1.

[0057] As Figure 2 and Figure 3As shown, a magnetic sheet 11 is disposed in the handwriting input area of the tablet terminal 1, and a position detection sensor 12 is disposed below the magnetic sheet 11 so as to overlap the magnetic sheet 11 in a direction orthogonal to the surface of the tablet terminal 1.

[0058] As Figure 3 (A) shows, the magnetic sheet 11 is a sheet-like member formed by encapsulating a plurality of microcapsules 113 in which magnetic material powder (e.g., iron powder 113Fe) (represented as black dots in Figure 3 (A) and Figure 3 (B)) can swim into the gap between a sheet-like resin substrate 111 made of, for example, PET (Polyethylene Terephthalate) and a sheet-like resin substrate 112. In this case, at least the sheet-like resin substrate 111 is made of a transparent material. The magnetic sheet 11 can be, for example, the magnetic sheet used in the Clean Note Kaite manufactured by Plus Corporation.

[0059] In this embodiment, as Figure 2 and Figure 3 (A) shows, the surface 111a of the sheet-like resin substrate 111 of the magnetic sheet 11 becomes the handwriting input surface 1A.

[0060] When the magnetic pole does not approach or contact the magnetic sheet 11, as Figure 3 (B) shows, the iron powder 113Fe in each microcapsule 113 is in a state of being present at arbitrary irregular positions, and the surface of the magnetic sheet 11, that is, the handwriting input surface 1A, becomes a state of a prescribed background color (e.g., white) as a whole.

[0061] And, when the magnetic pole approaches or contacts the surface 111a side of the sheet-like resin substrate 111 of the magnetic sheet 11, as Figure 3 (A) shows, the iron powder 113Fe in the microcapsules 113 near the position where the magnetic pole approaches or contacts is attracted to the magnetic pole side. Therefore, at the position where the magnetic pole approaches or contacts, the surface of the magnetic sheet 11, that is, the handwriting input surface 1A, presents the color of the iron powder 113Fe (e.g., black). The position of the iron powder 113Fe in the microcapsules 113 is maintained even when the magnetic pole moves away. Therefore, if the magnetic pole that approaches or contacts the surface of the magnetic sheet 11 moves, its movement trajectory becomes a black line and appears on the surface of the magnetic sheet 11.

[0062] It should be noted that the handwriting input device of this embodiment is attached with a function to restore the state of the iron powder 113Fe in the microcapsules 113 that are magnetically attracted to the surface of the magnetic sheet 11 of the tablet terminal 1 to Figure 3An eraser 3 for the state of an irregular position shown in (B). The eraser 3 is provided with a magnet for an eraser as is well known, and can erase the entire area of a specified size, and by using its corners, can also finely erase a part of the note mark.

[0063] The position detection sensor 12 is provided overlapping the magnetic sheet 11 on the back side of the magnetic sheet 11. And, in the tablet terminal 1, a position detection device unit 13 including a position detection circuit and other electronic components described later is provided using the area inside the position detection sensor 12 and the area inside the operation panel unit 1B. In this embodiment, the position detection sensor 12 constitutes a part of the position detection device unit 13.

[0064] The position detection device unit 13 of this embodiment is of the electromagnetic induction type, and the position detection sensor 12 and the electronic pen 2 are electromagnetically inductively coupled to perform signal interaction as described later. And, the position detection device unit 13 detects the coordinate position on the handwriting input surface 1A indicated by the electronic pen 2 based on the signal interaction between the position detection sensor 12 and the electronic pen 2.

[0065] In this embodiment, as Figure 3 (A) shows, the position detection sensor 12 is formed by disposing electrode conductors on a flexible sheet 121 made of an insulating material to form a plurality of circular coils. In this embodiment, on the flexible sheet 121, a plurality of X-axis direction circular coils are disposed at a specified interval in the lateral direction (X-axis direction) of the handwriting input surface 1A, and a plurality of Y-axis direction circular coils are disposed at a specified interval in the longitudinal direction (Y-axis direction).

[0066] In this embodiment, in order to avoid the overlap of the electrode conductors constituting the X-axis direction circular coils and the Y-axis direction circular coils arranged in mutually orthogonal directions, as Figure 3 (A) shows, electrode conductors 122 and 123 are formed on the front and back surfaces of the flexible sheet 121, and by using through holes (not shown) penetrating the flexible sheet 121, the X-axis direction circular coils and the Y-axis direction circular coils are formed on the flexible sheet 121. It should be noted that in Figure 2 , on the flexible sheet 121 of the position detection sensor 12, the electrode conductors 122 and 123 are shown as linear conductors for convenience, but actually, they constitute circular coils (refer to Figure 7 described later).

[0067] <Structural example of the electronic pen 2>

[0068] In this embodiment, as described above, the electronic pen 2 transmits and receives signals to and from the position detection sensor 12 of the position detection device unit 13 of the tablet terminal 1 by electromagnetic induction, so that the indicated position thereof is detected by the position detection device unit 13 of the tablet terminal 1. The mechanical structure of the electronic pen 2 in this embodiment can be set to the same structure as that of a known electronic pen using electromagnetic induction, except that the core is made of a magnet (a permanent magnet in this example). Therefore, here, only the structure of the main part of the electronic pen 2 will be described, and the description of the structures of other parts will be omitted.

[0069] As Figure 1 shown, the electronic pen 2 in this embodiment has an electronic pen main body part 21 on the side of the opening 20a in the axial direction of the hollow part of a cylindrical housing 20 made of resin, for example, and an eraser function part 22 on the side of the opening 20b in the other axial direction.

[0070] The electronic pen main body part 21 includes a coil 211, a magnetic core around which the coil 211 is wound (a ferrite core 212 in this example), a core 213 made of a magnet, a pen pressure detection part 214, and a capacitor 215 that forms a resonance circuit together with the coil 211.

[0071] In addition, the eraser function part 22 includes a coil 221, a magnetic core around which the coil 221 is wound (a ferrite core 222 in this example), a core 223 made of a magnet, and a capacitor 224 that forms a resonance circuit together with the coil 221.

[0072] Figure 4 is a diagram for explaining a structural example of the electronic pen main body part 21. In the electronic pen main body part 21 of this embodiment, as Figure 4 (A) shows, the side of the ferrite core 212 around which the coil 211 is wound, opposite to the nib side, is joined to a cylindrical body part 216 made of resin, for example.

[0073] As Figure 4 (A) shows, in the ferrite core 212 of this example, a through hole 212a having a specified diameter r1 (for example, r1 = 1 mm) in the axial direction for inserting the core 213 is formed in a ferrite material having a cylindrical shape. A tapered part 212b that gradually becomes thinner is formed on the nib side of the ferrite core 212, and is configured to make the magnetic coupling with the position detection sensor 12 of the position detection device unit 13 stronger than in the case where there is no tapered part 212b.

[0074] Further, in this embodiment, a pen pressure detection unit 214 is provided near the joint portion of the cylindrical body portion 216 and the ferrite core 212. For example, the pen pressure detection unit 214 is configured to use a semiconductor element whose static capacitance varies according to the pen pressure disclosed in Japanese Patent Application Laid-Open No. 2013-161307. It should be noted that the pen pressure detection unit 214 can also be configured to use a variable capacitance capacitor whose static capacitance changes according to the pen pressure of a pen pressure detection unit having a well-known mechanism structure described in, for example, the patent document: Japanese Patent Application Laid-Open No. 2011-186803.

[0075] A printed circuit board 217 is also housed in the cylindrical body portion 216. A capacitor 215 that is connected in parallel with the coil 211 to form a resonant circuit is provided on the printed circuit board 217. Further, the variable capacitance capacitor formed by the pen pressure detection unit 214 is connected in parallel with the capacitor 215 formed on the printed circuit board 217 to form a part of the resonant circuit.

[0076] Further, as Figure 4 shown in (B), the ferrite core 212 is combined with the cylindrical body portion 216 by fitting the side of the ferrite core 212 opposite to the nib side into the recess 216a provided in the cylindrical body portion 216. Although not shown in the figure, when the ferrite core 212 is combined with the cylindrical body portion 216, one end 211a and 211b of the coil 211 are electrically connected in such a manner as to be connected in parallel with the capacitor 215 of the printed circuit board 217 provided in the cylindrical body portion 216.

[0077] In this embodiment, the core body 213 is composed of a rod-shaped magnet having a diameter smaller than the inner diameter r1 of the through hole 212a of the ferrite core 212. In this example, the magnetic pole on the nib portion 213a side is set to the N pole, and the magnetic pole of the end portion (tail end portion) 213b on the side opposite to the nib portion 213a in the axial direction is set to the S pole. Further, the length of the core body 213 in the axial direction is longer than the length of the ferrite core 212 in the axial direction.

[0078] In this embodiment, as Figure 4 shown in (B), the core body 213 configured as described above is inserted through the through hole 212a of the ferrite core 212 and is directly fitted into the fitting hole 214a of the pen pressure detection unit 214 by fitting the tail end portion 213b. In this fitted state, the core body 213 is set in a state where the nib portion protrudes from the opening on the front end side of the ferrite core 212. Thus, the magnetic pole on the nib portion 213a side of the core body 213 is at a position farther from the nib side end portion of the ferrite core 212.

[0079] Further, in this embodiment, as Figure 4As shown in (B), the tip portion 213a of the core 213 projects outward from the opening 20a of the housing 20 of the electronic pen 2 together with a part of the tip side of the ferrite core 212. Thereby, the pen pressure applied to the tip portion 213a of the core 213 is directly transmitted to the pen pressure detection portion.

[0080] The electronic pen 2 of this embodiment receives the AC signal of the frequency f0 transmitted by the position detection sensor 12 of the position detection device unit 13 by electromagnetic induction coupling using a resonance circuit. And, the resonance circuit of the electronic pen 2 feeds back the received AC signal to the position detection sensor 12 by electromagnetic induction coupling. In the position detection device unit 13, the indication position of the electronic pen 2 is detected by detecting the position of the AC signal fed back from the electronic pen 2 on the position detection sensor 12. In addition, the position detection device unit 13 detects the pen pressure applied to the electronic pen 2 by detecting a change in the frequency or phase of the AC signal received from the electronic pen 2.

[0081] In order to be able to perform the interaction of the AC signal between the electronic pen 2 and the position detection sensor 12 well in a manner that minimizes energy loss, the resonance frequency of the resonance circuit of the electronic pen 2 is selected to be equal to the frequency f0 of the AC signal from the position detection device unit 13.

[0082] However, in this embodiment, it is necessary to consider the influence of the core 213 being made of a magnet. That is, when the core 213 made of a magnet is inserted into the through hole 212a of the ferrite core 212, the magnetic characteristics of the ferrite core 212 decrease, and thus, the inductance value of the coil 211 decreases. Therefore, even if the resonance frequency of the resonance circuit composed of the coil 211 and the capacitor 215 is selected to be equal to the frequency f0 of the AC signal transmitted from the position detection device unit 13, the effective resonance frequency is higher than the frequency f0 by the amount of decrease Δf in the inductance of the coil 211 caused by the core 213 made of a magnet (refer to Figure 5 the resonance characteristic diagram of the electronic pen 2 shown in (A)).

[0083] Then, in the electronic pen 2 of this embodiment, in advance considering the amount of decrease in the inductance of the coil 211 caused by the core 213 made of a magnet, the resonance frequency of the resonance circuit composed of the coil 211 and the capacitor 215 is selected to be a frequency f1 (<f0) lower than the frequency f0 of the AC signal transmitted from the position detection device unit 13 (refer to Figure 5 the resonance characteristic diagram of (B)). In this way, in the state where the core 213 is inserted into the through hole 212a of the ferrite core 212, as Figure 5 shown in (B), the effective resonance frequency of the resonance circuit composed of the coil 211 and the capacitor 215 is equal to the frequency f0.

[0084] In addition, although not shown in the drawings, the position detection sensor 12 of the tablet terminal 1 of this embodiment is provided with a sheet-like magnetic member for electromagnetic shielding from the outside on the surface opposite to the surface facing the magnetic sheet 11.

[0085] When the electronic pen 2 approaches or contacts the handwriting input surface 1A of the tablet terminal 1, the DC magnetic flux from the core 213 composed of a magnet penetrates into the sheet-like magnetic member of the position detection sensor 12, and the magnetic characteristics of the sheet-like magnetic member decrease. As a result, the inductance value of the toroidal coil of the position detection sensor 12 decreases. Therefore, the magnetic coupling between the coil 211 of the electronic pen 2 and the toroidal coil of the position detection sensor 12 decreases, and the signal level of the signal exchanged between the electronic pen 2 and the position detection sensor 12 may become low.

[0086] However, as Figure 6 shown, compared with the range of the magnetic flux that detects the linked magnetic flux surrounded by the toroidal coil ( Figure 6 an example is a toroidal coil wound twice) 12LC formed in the position detection sensor 12 (the range marked with diagonal lines in Figure 6 ), the magnetic flux range of the magnetic pole of the tip portion 213a of the core 213 composed of a magnet is extremely small, and there is a certain distance between the tip portion 213a of the core 213 of the electronic pen 2 and the sheet-like magnetic member of the position detection sensor 12. Therefore, there is no influence to the extent that the accuracy of coordinate detection at the position detection device unit 13 is impaired. That is, the magnetic flux of the tip portion 213a of the core 213 composed of a magnet has almost no influence on the magnetic coupling between the coil 211 of the electronic pen 2 and the position detection sensor 12 and the magnetic characteristics of the part composed of the coil 211 of the electronic pen 2, the position detection sensor 12, and the sheet-like magnetic member of the position detection sensor 12.

[0087] As described above, in the handwriting input device of this embodiment, even if the core 213 of the electromagnetic induction type electronic pen 2 is composed of a magnet, the coordinate position indicated by the electronic pen 2 can be detected with the same accuracy as before in the position detection device unit 13.

[0088] The eraser function unit 22 of the electronic pen 2 can be configured in the same manner as the above-described electronic pen main body unit 21. That is, it is configured by inserting a core 223 composed of a rod-shaped magnet into the through-hole of the ferrite core 222 around which the coil 221 is wound. In this case, the magnetic pole of the core 223 is configured such that the front end side is set as the S pole and the side opposite to the front end side is set as the N pole, having a polarity opposite to the magnetic pole of the core 213 of the electronic pen main body unit 21.

[0089] Therefore, if the front end of the core 223 of the eraser function unit 22 approaches or contacts the magnetic sheet 11 in a manner that traces the note track appearing on the surface of the magnetic sheet 11, the iron powder 113Fe in the microcapsule 113 magnetized to the S pole by the magnetic pole of the N pole of the tip 213a of the core 213 of the electronic pen main body 21 is repelled from the surface of the magnetic sheet 11 by the magnetic pole of the S pole at the front end of the core 223 of the eraser function unit 22, and the note track appearing on the surface of the magnetic sheet 11 is erased.

[0090] In the position detection device unit 13 of the handwriting input device according to this embodiment, in addition to the AC signal of the frequency f0 for note input detection described above, an AC signal having a frequency f2 (≠f0≠f1) that can be clearly distinguished from the frequency f0 and used to detect the feedback signal is sent to the electronic pen 2 as detection for erasure indication via the position detection sensor 12.

[0091] Moreover, the coil 221 of the eraser function unit 22 of the electronic pen 2 is connected in parallel with the capacitor 224 to form a resonant circuit. However, the resonant frequency of this resonant circuit is configured to be equal to the frequency f2 of the AC signal for detection of the erasure indication described above, receives the AC signal of the frequency f2 from the position detection device unit 13, and feeds it back to the position detection sensor 12. In this case, the frequency of the resonant circuit of this eraser function unit 22 is also the same as the resonant frequency of the resonant circuit of the electronic pen main body 21, and considering the influence of the core 223 made of a magnet, it is selected to be a frequency lower than the frequency f2 so as to be equal to the frequency of the AC signal for detecting the erasure indication of the position detection device unit 13 when the core 223 is inserted and assembled in the through hole of the ferrite core 222.

[0092] In a state where the user brings the core 223 of the eraser function unit 22 of the electronic pen 2 close to or in contact with the surface of the magnetic sheet 11, the AC signal for detection of the erasure indication from the position detection device unit 13 is fed back as an AC signal of the frequency f2 via the resonant circuit of the eraser function unit 22. Therefore, the position detection device unit 13 receives this feedback signal via the position detection sensor 12, and detects the coordinate position where the erasure indication has been made by detecting the position of this reception on the position detection sensor 12.

[0093] In this way, in the handwriting input device according to this embodiment, by bringing the tip 213a of the electronic pen main body 21 of the electronic pen 2 close to or in contact with the handwriting input surface 1A, the note track can be displayed on the surface of the magnetic sheet 11, and the electronic data (note data and pen pressure data) of the note track can be detected and stored.

[0094] Furthermore, by bringing the front end of the core 223 of the eraser function unit 22 of the electronic pen 2 close to or in contact with the handwriting input surface 1A and moving in a manner that traces the note track displayed on the surface of the magnetic sheet 11, the note track displayed on the surface of the magnetic sheet 11 can be erased, and the corresponding note data and pen pressure data can be deleted from the storage unit and erased.

[0095] It should be noted that, when the writing trace displayed on the magnetic sheet 11 is erased using the eraser 3 for the magnetic sheet 11 , the writing data and the writing pressure data stored in the position detection device unit 13 are not erased.

[0096] It should be noted that in this embodiment, the eraser function section 22 of the electronic pen 2 is not provided with a writing pressure detection section. However, of course, the eraser function section 22 may also be provided with a writing pressure detection section similar to the electronic pen main body 21 .

[0097] In the electronic pen 2 of this embodiment, when the pen tip 213a of the core 213 of the electronic pen body 21 is used to protrude to the outside, as shown in FIG. Figure 4 As shown in (B), not only the core body 213 but also a part of the ferrite core 212 protrudes from the opening 20a of the housing 20, and the distance from the front end of the tapered portion 212b of the ferrite core 212 to the input surface of the position detection sensor 12 is shortened. Therefore, according to the electronic pen 2 of this embodiment, the electromagnetic coupling with the position detection sensor 12 is strengthened compared with the conventional electronic pen in which the ferrite core 212 stays in the hollow part of the housing 20. In addition, in this embodiment, since the front end side of the ferrite core 212 is set as the tapered portion 212b, the cross-sectional area of the front end of the ferrite core 212 is reduced, the magnetic flux density is increased, and the electromagnetic coupling with the position detection sensor 12 is strengthened.

[0098] Therefore, even when the electronic pen 2 of this embodiment is slimmed down, it is possible to achieve strong electromagnetic coupling with the position detection sensor 12 , and the position detection device unit 13 can detect the pointed position of the electronic pen 2 with high sensitivity.

[0099] In this embodiment, the core 223 and the ferrite core 222 of the eraser function unit 22 are also configured similarly to the core 213 and the ferrite core 212 of the electronic pen body 21 .

[0100] <Configuration Example of Electronic Circuit of Handwriting Input Device of Embodiment>

[0101] Figure 7 1 is a diagram showing an electronic circuit configuration of a tablet terminal 1 and an electronic pen 2 constituting the handwriting input device of this embodiment.

[0102] like Figure 7As shown in the figure, the electronic pen 2 includes a resonance circuit RCp of the electronic pen main body 21 composed of a coil 211, a capacitor 215, and a variable capacitance capacitor 214C composed of a pen pressure detection unit 214, and a resonance circuit RCe of the eraser function unit 22 composed of a coil 221 and a capacitor 224.

[0103] When the tip 213a of the core 213 of the electronic pen main body 21 of the electronic pen 2 approaches or contacts the handwriting input surface 1A of the tablet terminal 1, the resonance circuit RCp is electromagnetically inductively coupled with the position detection sensor 12 to exchange an AC signal of frequency fo. When the tip 213a of the core 213 of the electronic pen main body 21 of the electronic pen 2 approaches or contacts the handwriting input surface 1A of the tablet terminal 1, the resonance circuit RCp is electromagnetically inductively coupled with the position detection sensor 12 to exchange an AC signal of frequency f0.

[0104] An X-axis direction loop coil group 124X and a Y-axis direction loop coil group 125Y are formed in the position detection sensor 12 of the position detection device unit 13. The position detection circuit 130 of the position detection device unit 13 uses electromagnetic coupling to send signals to the resonance circuit RCp and the resonance circuit RCe of the electronic pen 2 through the X-axis direction loop coil group 124X and the Y-axis direction loop coil group 125Y of the position detection sensor 12.

[0105] In this case, the position detection circuit 130 is configured to perform note input detection processing and erasure input detection processing in a time-division manner. That is, the position detection circuit 130 alternately executes a note input detection period TP for performing note input detection processing and an erasure input detection period TE for performing erasure input detection processing. During the note input detection period TP, the position detection circuit 130 sends an AC signal of frequency f0 to the electronic pen 2 through the position detection sensor 12. In addition, during the erasure input detection period TE, the position detection circuit 130 sends an AC signal of frequency f2 to the electronic pen 2 through the position detection sensor 12.

[0106] Further, when the electronic pen 2 brings the tip 213a of the core 213 of the electronic pen main body 21 close to or into contact with the handwriting input surface 1A of the tablet terminal 1, the resonance circuit RCp receives an AC signal of the frequency f0 in the note input detection period TP from the position detection sensor 12, and feeds back the AC signal from this resonance circuit RCp to the position detection sensor 12. At this time, since the frequency f2 in the erasure input detection period TE is different from the resonance frequency f0 of the resonance circuit RCp, the reception level of this signal becomes low in the resonance circuit RCp. Therefore, the level of the signal fed back to the position detection sensor 12 also becomes small and becomes below the detection target level in the position detection circuit 130. Thus, the position detection circuit 130 only performs note input detection in the note input detection period TP in a state where the tip 213a of the core 213 of the electronic pen main body 21 of the electronic pen 2 is close to or in contact with the handwriting input surface 1A of the tablet terminal 1, and does not perform erasure input detection processing in the erasure input detection period TE.

[0107] In addition, when the electronic pen 2 brings the front end of the core 223 of the eraser function unit 22 close to or into contact with the handwriting input surface 1A of the tablet terminal 1, the resonance circuit RCe receives an AC signal of the frequency f2 in the erasure input detection period TE from the position detection sensor 12, and feeds back the AC signal from this resonance circuit RCe to the position detection sensor 12. At this time, since the frequency f0 in the note input detection period TP is different from the resonance frequency f2 of the resonance circuit RCe, the reception level of this signal becomes low in the resonance circuit RCe. Therefore, the level of the signal fed back to the position detection sensor 12 also becomes small and becomes below the detection target level in the position detection circuit 130. Thus, the position detection circuit 130 only performs erasure input detection in the erasure input detection period TE in a state where the front end of the core 223 of the eraser function unit 22 of the electronic pen 2 is close to or in contact with the handwriting input surface 1A of the tablet terminal 1, and does not perform note input detection processing in the note input detection period TP.

[0108] Further, in the position detection circuit 130, the feedback signal from the resonance circuit RCp or the resonance circuit RCe of the electronic pen 2 is received through the position detection sensor 12 by electromagnetic coupling. And the position detection circuit 130 detects the position on the position detection sensor 12 indicated by the electronic pen 2 according to the position on the position detection sensor 12 where the received signal is detected.

[0109] In addition, in the note input detection period TP, the position detection circuit 130 detects a change in the resonance frequency of the resonance circuit RCp by detecting a change in the phase of the signal received from the electronic pen 2, and detects the pen pressure applied to the core 213 of the electronic pen main body 21 of the electronic pen 2.

[0110] In the position detection circuit 130, a position detection control unit 137 is provided which controls time-division processing for note input detection processing and erasure input detection processing, and controls the position detection processing and pen pressure detection processing described below. The position detection control unit 137 switches the oscillation frequency of the oscillator 131 to be frequency f0 during the note input detection period TP and to be frequency f2 during the erasure input detection period TE. Also, in this example, in addition to controlling so as not to perform the pen pressure detection processing during the erasure input detection period TE, it is controlled so as to perform the same detection processing during the note input detection period TP and the erasure input detection period TE.

[0111] In the position detection circuit 130, a selection circuit 126 is provided which is connected to the X-axis direction toroidal coil group 124X and the Y-axis direction toroidal coil group 125Y of the position detection sensor 12. This selection circuit 126 sequentially selects one toroidal coil from the two toroidal coil groups 124X and 125Y, sends a signal to the resonance circuit RCp or the resonance circuit RCe, and receives the signal fed back from the resonance circuit RCp or the resonance circuit RCe.

[0112] For the selection circuit 126, a switching circuit 133 that is switched and controlled by the position detection control unit 137 is connected. When the switching circuit 133 is connected to the transmission-side terminal T, an AC signal is supplied from the oscillator 131 to the selection circuit 126. When the switching circuit 133 is connected to the reception-side terminal R, the signal from the selection circuit 126 is supplied to the indication position detection circuit 135 and the pen pressure detection circuit 136 through the amplifier 134.

[0113] The indication position detection circuit 135 demodulates the received signal, which is the induced voltage generated in the toroidal coil of the position detection sensor 12, converts its demodulated output signal into a digital signal, and outputs it to the position detection control unit 137. The position detection control unit 137 calculates the coordinate values of the indication position in the X-axis direction and the Y-axis direction of the electronic pen 2 based on the digital signal from the indication position detection circuit 135, that is, the level of the voltage value of the induced voltage generated in each toroidal coil.

[0114] On the other hand, the pen pressure detection circuit 136 synchronously demodulates the output signal of the receiving amplifier 134 using the AC signal from the oscillator 131 to obtain a signal having a level corresponding to the phase difference (frequency shift) between them, converts the signal corresponding to the phase difference (frequency shift) into a digital signal, and outputs it to the position detection control unit 137. The position detection control unit 137 detects the pen pressure applied to the tip 213 of the electronic pen body 21 of the electronic pen 2 based on the digital signal from the pen pressure detection circuit 136, that is, the level of the signal corresponding to the phase difference (frequency shift) between the transmitted radio wave and the received radio wave.

[0115] During the note input detection period TP, the position detection control unit 137 sets the coordinate data of the indicated position of the electronic pen 2 detected as note data, and supplies it to the control unit 140 together with the detected pen pressure data. In addition, during the erasure input detection period TE, the position detection control unit 137 sets the coordinate data of the indicated position of the electronic pen 2 detected as erasure data and supplies it to the control unit 140.

[0116] The control unit 140 includes a memory unit 141 and a wireless communication unit 142. In addition, although not shown in the figure, the control unit 140 includes a rechargeable battery, a charging circuit, and a power supply circuit. And for this control unit 140, an operation unit 143 composed of a power button 1Ba, a note input end button 1Bb, and an information transmission button 1Bc provided on the operation panel unit 1B is connected, and an indicator unit 144 composed of a power indicator 1Bd and a communication indicator 1Be is connected.

[0117] If the power button 1Ba of the operation unit 143 is pressed and turned on, the control unit 140 generates a power supply voltage Vcc and supplies it to each unit, making the tablet terminal 1 in an operating state. At this time, the control unit 140 lights up the power indicator 1Bd and reports the power-on to the user. If the power button 1Ba is pressed again, it becomes an indication of power-off, and the control unit 140 stops supplying the power supply voltage Vcc to each unit, becoming a non-operating state, and the power indicator 1Bd is turned off.

[0118] The control unit 140 stores the note data and pen pressure data received from the position detection control unit 137 in the memory 141. And if the control unit 140 receives erasure data from the position detection control unit 137, it erases the corresponding note data and pen pressure data stored in the memory 141.

[0119] Moreover, if the control unit 140 detects that the user has pressed the note input end button 1Bb, it stores the group of note data and pen pressure data stored in the memory 141 up to that time as data for one page amount. At this time, page identification information is given to the data for one page amount.

[0120] Therefore, after the user presses the note input end button 1Bb, the user can use the eraser 3 to erase the entire note trace on the surface of the magnetic sheet 11 and perform a new handwritten input. At this time, since the eraser 3 is only for erasing the note trace on the surface of the magnetic sheet 11, the control unit 140 does not erase the note data in page units stored in the memory 141.

[0121] After completely erasing all the note traces that appear on the surface of the magnetic sheet 11 as described above, if the user uses the electronic pen 2 to perform new note input and erasure, the control unit 140 stores the new note data and pen pressure data in the memory 141. Then, if the user presses the note input end button 1Bb, the note data and pen pressure data newly stored in the memory 141 are stored in the memory 141 as data of another page.

[0122] Moreover, in this embodiment, the control unit 140 is provided with a wireless communication unit 142 and can perform wireless communication with a server device constituted by, for example, a computer. Also, in an environment where wireless communication with the server device is possible, if the user presses the information transmission button 1Bc on the operation panel unit 1B of the operation tablet terminal 1, the control unit 140 transmits the note data and pen pressure data in page units stored in the memory 141 to the server device and erases the memory 141. At this time, during the period when the control unit 140 transmits the note data and pen pressure data to the server device, the communication indicator 1Be is lit to report that the note data and pen pressure data are being transmitted to the server device.

[0123] It should be noted that the control unit 140 may be configured such that, instead of transmitting the note data and pen pressure data in page units stored in the memory 141 to the server device by the user operating the information transmission button, when the note input end button is pressed, the note data and pen pressure data in page units are automatically transmitted to the server device. In this case, there is no need to provide an information transmission button.

[0124] <User's usage mode of the handwriting input device of the embodiment>

[0125] An example of the process of the user's usage mode of the handwriting input device of this embodiment configured as described above will be described.

[0126] The description starts from a state where there are no note traces on the handwriting input surface 1A on the surface of the magnetic sheet 11 of the tablet terminal 1. In this state, the user presses the power button 1Ba of the tablet terminal 1 to turn on the power and supply power to the tablet terminal 1.

[0127] Then, the user holds the electronic pen 2 and brings the tip 213a of the core 213 of the electronic pen main body 21 close to or into contact with the handwriting input surface 1A to perform note input. Since the core 213 is made of a magnet, among the surfaces of the magnetic sheet 11, the iron powder in the microcapsules 113 at the position where the core 213 approaches or contacts is attracted, and the note trace changes color, for example, to black, and the user can visually confirm it.

[0128] Meanwhile, in the tablet terminal 1, the position detection sensor 12 disposed on the back side of the magnetic sheet 11 and the coil 211 of the resonance circuit RCp of the pen body portion 21 of the electronic pen 2 are inductively coupled electromagnetically. In the position detection device portion 13, note data and pen pressure data corresponding to the note trace appearing on the surface of the magnetic sheet 11 are detected and stored in the memory 141 of the control portion 140.

[0129] When the user wants to erase the input note trace during this note input, the user holds the electronic pen 2 in reverse, and brings the front end portion of the core 223 of the eraser function portion 22 close to or into contact with the position of the note trace to be erased on the surface of the magnetic sheet 11 of the tablet terminal 1. Then, the portion of the note trace appearing on the surface of the magnetic sheet 11 is restored to the background color of the magnetic sheet 11 through the core 223 composed of a magnet and is erased. Meanwhile, the coil 221 of the resonance circuit RCe of the eraser function portion 22 of the electronic pen 2 and the position detection sensor 12 are inductively coupled electromagnetically. In the position detection device portion 13, erasure data of the note trace appearing on the surface of the magnetic sheet 11 is detected and supplied to the control portion 140. Receiving this erasure data, the control portion 140 erases the note data and pen pressure data corresponding to the erasure data from the memory 141.

[0130] And when the user observes the note trace appearing on the surface of the magnetic sheet 11 and determines that the note input for one page is completed, the user presses the note input end button 1Bb on the operation panel portion 1B of the tablet terminal 1. Then, in the tablet terminal 1, as described above, the note data and pen pressure data stored in the memory 141 up to that point are stored in the memory 141 as data for one page amount, with page identification information added.

[0131] Next, when the user then wants to perform note input as another page, the user erases the note trace appearing on the surface of the magnetic sheet 11 using the eraser 3. Then, the user brings the tip portion 213a of the core 213 of the pen body portion 21 of the electronic pen 2 close to or into contact with the handwriting input surface 1A and performs note input. Then, when it is determined that the note input for one page amount is completed, the user presses the note input end button 1Bb. Then, in the memory 141, new note data and pen pressure data for one page amount are stored with identification information different from the previously stored data for one page amount.

[0132] It should be noted that even if the eraser 3 is not used for erasure, the note data and pen pressure data after pressing the note input end button 1Bb are stored in the memory 141 as new note data and pen pressure data for one page amount.

[0133] As described above, by using the tablet terminal 1 and the electronic pen 2, note data and pen pressure data in an amount of 1 to multiple pages can be stored in the memory 141 of the tablet terminal 1. The user takes the tablet terminal 1 home or to the company, wirelessly connects it to a computer that is set to communicate with the wireless communication unit 142, and presses the operation information sending button 1Bc. Then, the tablet terminal 1 wirelessly sends the note data and pen pressure data of 1 to multiple pages stored in the memory 141 to the computer. Then, in the tablet terminal 1, after the wireless transmission is completed, the stored data in the memory 141 is erased.

[0134] Therefore, afterwards, the tablet terminal 1 enters a state where it can accept new note inputs and repeat the above actions.

[0135] It should be noted that it is also possible to provide a storage unit for identifying the pen identification information of the electronic pen 2 in the electronic pen 2, and send the pen identification information of the storage unit to the position detection device unit 13 through electromagnetic induction coupling with the position detection sensor 12 or through an additional wireless communication unit provided separately. In the position detection device unit 13, the note data and pen pressure data are stored together with the page identification information and pen identification information.

[0136] <Effects of the Embodiment>

[0137] According to the handwriting input device of the above embodiment, by performing note input on the handwriting input surface 1A using the electronic pen 2 having a core made of a magnet, electronic data of note input composed of note data and pen pressure data can be obtained in the same manner as in the past. Moreover, by using the magnetic sheet 11 capable of representing note traces using a magnet, a display panel such as an LCD is not required, and it can be manufactured at low cost.

[0138] In addition, by using the magnetic sheet 11 that can easily erase note traces by using the eraser 3 and the eraser function unit 22 of the electronic pen 2, there is no need to use paper as in Patent Document 3, it is convenient to carry, and there is no eraser debris in the case of paper. Therefore, it is also advantageous in this regard.

[0139] In addition, the electronic pen 2 constituting the handwriting input device of this embodiment can be configured to have the same structure as an existing electromagnetic induction type electronic pen except that the core is made of a magnet. Therefore, there is also an advantage that it can be configured at low cost.

[0140] In addition, the position detection sensor 12 and the position detection circuit 130 of the position detection device unit of the handwriting input device of the above embodiment can directly use existing electromagnetic induction type position detection sensors and position detection circuits. Therefore, it is also cost-effective in this regard.

[0141] [Modification Example of the Core]

[0142] In the above-described embodiment, the cores 213 and 223 are composed only of rod-shaped magnets, but the structure is not limited to this.

[0143] <The first example of other structural examples of the core>

[0144] Figure 8 (A) and (B) are diagrams for explaining the first modification example of the core applied to the main body portion 21 of the electronic pen. Figure 8 (A) is an exploded view of a part of the core 231 of the first example and the ferrite core 212 wound with the coil 211. Additionally, Figure 8 (B) shows a state in which the core 231 of the first example is inserted through the through hole 212a of the ferrite core 212 wound with the coil 211.

[0145] As Figure 8 (A) and (B) show, in the first example, the core 231 is composed of a rod-shaped magnet member 2311 and a tube member 2312 made of a hard material (such as metal or hard resin). In this example, similar to the core 213, the magnetic pole on the end 2311a side in the axial direction of the tip portion of the rod-shaped magnet member 2311 is set as the N pole, the opposite magnetic pole is set as the S pole, and the outer diameter is configured to be thinner than the outer diameter of the core 213.

[0146] The outer diameter of the tube member 2312 is selected to be a value smaller than the inner diameter r1 of the through hole 212a of the ferrite core 212 wound with the coil 211. Additionally, the inner diameter of the tube member 2312 is selected to be a value slightly smaller than the outer diameter of the rod-shaped magnet member 2311. And, as Figure 8 (B) shows, the rod-shaped magnet member 2311 is press-fitted and inserted into the hollow portion 2312a of the tube member 2312 to form the core 231 in which the magnet member 2311 and the tube member 2312 are integrated. In this case, the magnet member 2311 and the tube member 2312 may also be bonded using an adhesive material.

[0147] In this case, the axial length of the tube member 2312 is selected to be shorter than the axial length of the magnet member 2311. In the core 231, one end in the axial direction of the magnet member 2311 is configured to protrude from one end in the axial direction of the tube member 2312 as the tip portion 2311a. Additionally, in the first example, the other end in the axial direction of the magnet member 2311 is also configured to protrude from the other end in the axial direction of the tube member 2312. It should be noted that the other end in the axial direction of the magnet member 2311 may not protrude from the other end in the axial direction of the tube member 2312.

[0148] And, asFigure 8 (As shown in (B), one end 2311a of the magnet member 2311 of the core body 231 that forms the nib portion is configured to protrude from the nib-side end of the ferrite core 212, including a part of the tube member 2312. Thus, the magnetic pole of one end 2311a of the magnet member 2311 of the core body 231 that forms the nib portion is at a position farther from the nib-side end of the ferrite core 212.)

[0149] The core body 231 of this first example can be used as the electronic pen 2 with a core made of a magnet to obtain the same effects as those of the above-described embodiment. Moreover, the core body 231 of this first example is particularly formed by inserting a rod-shaped magnet member 2311 into the hollow portion 2312a of a tube member 2312 with high rigidity. Therefore, even if the rod-shaped magnet member 2311 is thin, it is protected by the tube member 2312, and it is possible to easily ensure the necessary and sufficient rigidity as a core body.)

[0150] <Second example of other structural examples of the core body>

[0151] Figure 8 ((C) and (D) are diagrams for explaining a second example of a modified example of the core body applied to the main body portion 21 of the electronic pen.) Figure 8 ((C) is an exploded view of a part of the core body 232 of this second example and the ferrite core 212 wound with the coil 211. In addition,) Figure 8 ((D) shows a state in which the core body 232 of the second example is inserted through the through hole 212a of the ferrite core 212 wound with the coil 211.)

[0152] As Figure 8 (shown in (C) and (D), in this second example, the core body 232 is composed of a rod-shaped magnet member 2321 formed by arranging and connecting a plurality of magnet segments 2321m in the axial direction and a tube member 2322. The tube member 2322 is made of a hard material such as metal or hard resin, similar to the tube member 2312 of the core body 231 of the first example, and is configured to have the same outer diameter, inner diameter, and length as the tube member 2312 of the core body 231 of the first example.)

[0153] The magnet segment 2321m is equivalent to a cylindrical structure obtained by cutting the magnet member 2311 of the core body 231 of the first example into circular pieces in a direction orthogonal to its axial direction. And as Figure 8As shown in (D), the core 232 of the second example is formed by press-fitting and engaging a magnet member 2321, which is obtained by arranging and connecting a plurality of cylindrical magnet segments 2321m in a row, into the hollow portion 2322a of a tube member 2322. In this case, the core 232 can also be formed by sequentially press-fitting and connecting a plurality of cylindrical magnet segments 2321m into the hollow portion 2322a of the tube member 2322. It should be noted that the magnet segments 2321m can be bonded to each other and to the tube member 2322 using an adhesive material.

[0154] In the core 232 of the second example, one end of the magnet member 2321 in the axial direction is also configured to protrude from one end of the tube member 2322 in the axial direction as a nib portion 2321a. It should be noted that the other end of the magnet member 2321 in the axial direction can be configured to protrude from the other end of the tube member 2322 in the axial direction or may not protrude.

[0155] And, as Figure 8 shown in (D), the nib portion 2321a of the core 232 is configured to protrude beyond the nib-side end of the ferrite core 212, including a part of the tube member 2322. Thus, the magnetic pole of the end 2321a of the magnet member 2321 of the core 232, which serves as the nib portion, is located at a position farther from the nib-side end of the ferrite core 212.

[0156] The core 232 of the second example can also function as an electronic pen 2 using a core made of a magnet to achieve the same effects as those of the above-described embodiments. In particular, since the core 232 of the second example is formed by connecting a plurality of magnet segments 2321m in a row, it has the effect of improving the shock resistance when an impact load is applied to the end 2321a of the magnet member 2321 of the core 232, which serves as the nib portion.

[0157] <Third Example of Another Structural Example of the Core>

[0158] Figure 8 (E) is a diagram for explaining a third example of a modified example of the core applied to the main body portion 21 of the electronic pen. The cores 231 and 232 of the above-described first and second examples are configured such that one ends 2311a and 2321a of the magnetic members 2311 and 2321, which serve as their nib portions, are exposed to the outside. However, in this third example of the core, one end of a rod-shaped magnetic member, which serves as the nib portion, is covered by a protective member.

[0159] Figure 8(E) shows a state in which the core 233 of the third example is inserted through the through-hole 212a of the ferrite core 212 around which the coil 211 is wound. The structure of the core 233 in this example is the same as that in which one end 2321a of the magnetic member 2321 of the core 232 of the second example, which forms the nib portion, is covered with the protective cover 2331. In this Figure 8 (E), the same reference numerals are assigned to the parts that are the same as the components of the core 232 of the second example.

[0160] In this example, the protective cover 2331 is made of, for example, resin regardless of the material of the tube member 2322. When the tube member 2322 is made of metal, the protective cover 2331 can also be made of metal.

[0161] In addition, the protective cover 2331 can also be integrally formed on one end side of the tube member 2322. That is, a rod-shaped member having a hollow portion inside and covering one end 2321a side of the magnetic member 2321 of the core 232 can be prepared, and the magnet member 2321 is inserted through the opening on the side opposite to the nib side of the rod-shaped member to form the core 233.

[0162] According to the core 233 of the third example, the protective cover 2331 can be used to prevent the nib portion of the core made of a magnet from being damaged, and the friction when the handwriting input surface comes into contact with the nib portion of the core can be reduced.

[0163] It should be noted that in Figure 8 (E), a case is shown in which one end 2321a of the magnetic member 2321 of the core 232 of the second example, which forms the nib portion, is covered with a protective member, but the third example can also be applied to a case in which one end 2311a of the magnetic member 2311 of the core 231 of the first example, which forms the nib portion, is covered with a protective member.

[0164] It should be noted that the above first to third examples can of course be applied not only to the cores of the electronic pen main body 21, but also to the cores of the eraser function portion 22 in exactly the same way.

[0165] [Other embodiments or modification examples]

[0166] It should be noted that in the electronic pen 2 of the above-described embodiment, the nib-side end of the ferrite core 212 also protrudes outward from the opening 20a of the housing 20 of the electronic pen 2, but it may also be that only the nib portion 213a of the core 213 protrudes outward from the opening 20a, and the ferrite core 212 is configured to be present inside the hollow portion of the housing 20. The same applies to the eraser function portion 22.

[0167] In addition, the electronic pen 2 in the above-described embodiment is configured to include an eraser function unit 22 in addition to the electronic pen main body unit 21, but the eraser function unit 22 may also be configured as a member independent of the electronic pen 2.

[0168] In addition, in the above-described embodiment, the tip end portion of the core body 213 is directly fitted into the fitting concave portion 214a of the pen pressure detection unit 214, but a pen pressure transmission member may be provided between the tip end portion and the fitting concave portion 214a so that the core body 213 is indirectly fitted to the pen pressure detection unit.

[0169] Reference Numeral Explanation

[0170] 1... tablet terminal, 1A... handwriting input surface, 1B... operation panel unit, 2... electronic pen, 3... eraser, 11... magnetic sheet, 12... position detection sensor, 13... position detection device unit, 21... electronic pen main body unit, 22... eraser function unit, 211, 221... coil, 212, 222... ferrite core, 213, 223, 216, 217, 218... core body, 214... pen pressure detection unit, 215, 224... capacitor, 2311, 2321... magnet member, 2312, 2322... tube member, 2181... protective cover.

Claims

1. An electronic pen, comprising: A coil; A magnetic core around which the coil is wound and having a through-hole in the axial direction; A capacitor that forms a resonant circuit with the coil; and A core body inserted through the through-hole of the magnetic core, A signal having a frequency corresponding to the resonant frequency of the resonant circuit is transmitted between the electronic pen and a position detection sensor by electromagnetic induction coupling, Characterized in that, The core body has magnetic poles at the tip portion and the tail end portion on the side opposite to the tip portion, and the tip portion is configured to protrude outward from the opening of the housing of the electronic pen and be at a position away from the end portion on the tip side in the axial direction of the magnetic core, The frequency of the resonant circuit is selected as a frequency considering the influence of the magnetic flux of the magnetic poles of the core body.

2. The electronic pen according to claim 1, characterized in that, A pen pressure detection portion for directly or indirectly fitting the tail end portion side of the core body is provided in the housing via a pressure transmission member.

3. The electronic pen according to claim 1, characterized in that, The core body is composed of a rod-shaped magnet.

4. The electronic pen according to claim 1, characterized in that, The core body is formed by combining a plurality of magnets in a row in the axial direction.

5. The electronic pen according to claim 1, characterized in that, The core body is formed by housing a magnet in the hollow portion of a metal tube.

6. The electronic pen according to claim 1, characterized in that, The core body is formed by housing a magnet in the hollow portion of a resin tube.

7. The electronic pen according to claim 1, characterized in that, The front end portion on the tip side of the core body is covered by a protective member.

8. The electronic pen according to claim 1, characterized in that, An eraser function portion is provided on the side of the housing opposite to the tip portion side, The eraser function portion includes: A coil for the eraser function portion independent of the coil; A magnetic core for the eraser function portion around which the coil for the eraser function portion is wound and having a through-hole in the axial direction; A capacitor for the eraser function portion that forms a resonant circuit for the eraser function portion having a resonant frequency different from the resonant frequency of the resonant circuit with a frequency different from the resonant frequency of the resonant circuit; and A core body for the eraser function portion having magnetic poles at the front end portion and the tail end portion on the side opposite to the front end portion, inserted through the through-hole of the magnetic core for the eraser function portion, The front end portion of the core body for the eraser function portion protrudes outward from the opening on the side of the housing opposite to the tip portion side.

9. A handwriting input device, comprising: A position detection device portion, in which an electromagnetic induction type position detection sensor is disposed overlapping with a magnetic sheet whose color changes at a position where a magnetic pole approaches or contacts; and An electronic pen, Characterized in that, The electronic pen includes: A coil; A magnetic core around which the coil is wound and having a through-hole in the axial direction; A capacitor that forms a resonant circuit with the coil; and A core body inserted through the through-hole of the magnetic core, The core has magnetic poles at the tip portion and the tail end portion on the side opposite to the tip portion, and the tip portion is configured to protrude outward from the opening of the housing of the electronic pen and be at a position away from the tip side end portion in the axial direction of the magnetic core. Between the position detection sensor of the position detection device unit and the resonant circuit of the electronic pen, signals of a frequency corresponding to the resonant frequency of the resonant circuit are exchanged by electromagnetic induction coupling. The frequency of the resonant circuit is selected as a frequency considering the influence of the magnetic flux of the magnetic poles of the core.

10. The handwriting input device according to claim 9, wherein The position detection device unit transmits a signal of a specified frequency to the electronic pen by electromagnetic induction coupling through the position detection sensor. The electronic pen receives the signal of the specified frequency by using the resonant circuit, and feeds back the received signal to the position detection sensor by electromagnetic induction coupling. The frequency of the resonant circuit is a frequency corresponding to the frequency of the signal from the position detection device unit.

11. The handwriting input device according to claim 9, wherein The magnetic sheet has a layer composed of a plurality of microcapsules, and the microcapsules contain powder made of a magnetic material. At a position where the magnetic pole of the tip portion of the core of the electronic pen is close to or in contact with the magnetic sheet, the powder made of the magnetic material of the layer of the magnetic sheet is magnetically attracted to the magnetic pole side of the tip portion of the core, so that the color of the position on the surface of the magnetic sheet where the magnetic pole of the tip portion of the core is close to or in contact with it changes.

12. The handwriting input device according to claim 11, wherein An erasing member is provided, and the erasing member erases the changed color in the magnetic sheet by returning the powder that has come into proximity to or in contact with the tip portion of the core of the microcapsules of the layer of the magnetic sheet to its original position.

13. The handwriting input device according to claim 9, wherein The electronic pen has an eraser function portion on the side of the housing opposite to the tip portion side. The eraser function portion includes: A coil for the eraser function portion independent of the coil; A magnetic core for the eraser function portion, around which the coil for the eraser function portion is wound, and having a through hole in the axial direction; A capacitor for the eraser function portion, which forms an eraser function portion resonant circuit having a resonant frequency different from the resonant frequency of the resonant circuit together with the coil for the eraser function portion; and A core for the eraser function portion, having magnetic poles at the front end portion and the tail end portion on the side opposite to the front end portion, and inserted into the through hole of the magnetic core for the eraser function portion. The front end portion of the core for the eraser function portion protrudes outward from the opening on the side of the housing opposite to the tip portion side. The magnetic sheet restores the color of the portion where the color has changed to its original state at the position where the core for the eraser function portion of the eraser function portion is close to or in contact with it. In the position detection device unit, coordinate data of a position at which a resonance frequency for the eraser function unit is detected from the electronic pen by the position detection sensor is erased.

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