Electronic pen

Abstract

Provided is an electromagnetic induction type electronic pen that can prevent a state of ink leakage even in an underwater environment subjected to high water pressure.　The present invention comprises: a circuit board on which a capacitor constituting a resonance circuit together with a coil wound around a first magnetic body is disposed; a housing provided with a waterproof area in which the first magnetic body and the circuit board are arranged in a hollow space with the first magnetic body on the pen tip side and in which the first magnetic body and the circuit board are housed in a waterproof state; a pen tip part mounted on the pen tip side of the housing in a state of being movable in the axial direction; a second magnetic body disposed in the pen tip part so as to change the distance to an end part on the pen tip side of the first magnetic body; and an elastic member for elastically restoring the pen tip part and the second magnetic body, which have moved according to a load applied to the pen tip part, to an original position on the pen tip side when the load disappears. A sealing part configured to isolate the hollow space from the external space is formed in the waterproof area.

Description

Electronic Pen

[0001] This invention relates to an electronic pen, and more particularly to an electromagnetic induction type electronic pen having a pen pressure detection function.

[0002] An electronic pen generally has a configuration with a pen pressure detection function. In an electromagnetic induction type electronic pen, in order to realize this pen pressure detection function, a pen pressure detection element that constitutes a variable capacitance capacitor, for example, is provided on the rear end side of a ferrite core around which a coil is wound on the pen tip side, and many such elements are provided.

[0003] In this type of electronic pen, a through hole in the axial direction is provided in the ferrite core, and an opening is provided on one side in the axial direction of the pen housing. A core body whose tip protrudes from this opening is inserted through the through hole of the ferrite core so that the pen pressure applied to the tip of the core body can be transmitted to a pen pressure detection element disposed inside the housing. That is, the core body is configured to be movable in the axial direction, and in order to transmit the pen pressure applied to the tip of the core body to the pen pressure detection element disposed on the rear end side of the ferrite core, it has a configuration having an internal space communicating with the external space through the opening on the pen tip side of the housing.

[0004] By the way, recently, the scenes where electronic pens are used outdoors and in various environments have been increasing. However, an electromagnetic induction type electronic pen having a pen pressure detection function has a configuration having an internal space communicating with the external space through the opening on the pen tip side of the housing as described above. Therefore, water, dust, etc. may enter the internal space of the housing from the opening of the housing, affecting the electrical components and connection parts housed in the housing of the electronic pen and potentially causing the electronic pen to malfunction. In particular, in an electromagnetic induction type electronic pen, when water enters the part of the coil wound around the magnetic core, the characteristics of the resonance circuit deviate from the expected ones, resulting in a problem that proper operation cannot be achieved.

[0005] Therefore, recently there has been a demand for waterproof and dustproof electronic pens, and various proposals have been made to address this. For example, Patent Document 1 (Japanese Patent Application Publication No. 2018-18149) discloses a configuration for an electromagnetic induction type electronic pen having a pen pressure detection unit, in which water and dust are prevented from entering the coil portion.

[0006] Figures 8 and 9 are diagrams illustrating the main parts of an example of the internal structure of an electronic pen disclosed in Patent Document 1. Figure 8 is a diagram showing the pen tip side of the electronic pen 1 disclosed in Patent Document 1. Figure 9(A) is a diagram showing the main part of the pen tip side of Figure 8.

[0007] In the electronic pen 1 of this Patent Document 1, as shown in Figures 8 and 9(A), the following components are arranged in the hollow part of the cylindrical case (housing) 2, in the axial direction of the case 2, starting from the pen tip side: a cap member 4 constituting a sealing member, a coil member 5 consisting of a ferrite core 52 around which a coil 51 is wound, a coil member holder 6, a pressing member 7, a pen pressure detection module 8, and a circuit board holder 9. A circuit board 10 is housed and secured in the circuit board storage section 91 of the circuit board holder 9.

[0008] The ferrite core 52 has a through hole 52a at its central axis position for inserting the rod-shaped core body 3, as shown in Figures 8 and 9(A). The core body 3 has its tip protruding outward from the opening 2a of the case 2, as shown in Figure 8, and its rear end is fitted into the recessed hole 7a of the pressing member 7, as shown in Figure 9(A).

[0009] The cap member 4 is made of an elastic material and, as shown in Figure 8, has a cap shape that covers the pen tip side of the ferrite core 52. However, the cap member 4 is configured not to cover the through hole 52a of the ferrite core 52. The cap member 4 acts as a sealing member that eliminates the gap between the pen tip side portion of the ferrite core and the inner wall surface of the case 2, and at the pen tip side, it serves to block the space where the coil 51 wound around the ferrite core 52 is located from the external space through the opening 2a of the case 2.

[0010] The coil member holder 6 is made of an elastic material and is mounted on the rear end side of the ferrite core 52 opposite to the pen tip side, without covering the through hole 52a of the ferrite core 52. Figure 9(B) is a perspective view of the coil member holder 6. As shown in Figures 9(A) and (B), the coil member holder 6 has a fitting portion 61 for fitting and housing the rear end side of the ferrite core 52, and a projection 62 that protrudes from the fitting portion 61 toward the rear end side in the axial direction.

[0011] The pen pressure detection module 8 is configured by engaging and coupling a pen pressure detection unit 81 and a pen pressure transmission member 82. Figure 9(C) is a perspective view of the pen pressure transmission member 82.

[0012] As shown in Figures 9(A) and (C), the pressure transmission member 82 of the pressure detection module 8 is integrally formed with a cylindrical body portion 821 having a hollow portion 821a inside and a barrier 822 that closes the hollow space of the hollow portion 821a of the cylindrical body portion 821. The barrier 822 is made of a thin plate-like body.

[0013] As shown in Figure 9(A), the projection 62 of the coil member holder 6 is press-fitted into the hollow portion 821a of the cylindrical body portion 821 of the pressure transmission member 82. In this case, the pressing member 7 to which the rear end of the core body 3 is fitted has two ring-shaped projections 621 and 622 on the side surface of the projection 62 of the coil member holder 6, as shown in Figures 9(A) and (B). These ring-shaped projections 621 and 622 ensure that the coil member holder 6 is fitted into the pressure transmission member 82 without any gap being created between it and the inner wall of the pressure transmission member 82.

[0014] As shown in Figure 9(A), the pressing member 7, which has a fitting recessed hole 7a into which the rear end of the core body 3 is press-fitted, is provided in the hollow portion 821a of the cylindrical portion 821 of the pen pressure transmission member 82, with the tip of the pressing member 7 in contact with the barrier 822.

[0015] As shown in Figure 9(A), the pressure detection unit 81 consists of a pressure-sensitive unit 83 and a holder 84 that holds the pressure-sensitive unit 83 and also has a function for making an electrical connection. The holder 84 integrally comprises a holding portion 841 that holds the pressure-sensitive unit 83 and a connecting portion 842 for electrically connecting the two electrodes of the pressure-sensitive unit 83 held by the holding portion 841 to the circuit board 10 housed in the substrate holder 9.

[0016] The pressure-sensitive section 83 of the pressure-detecting section 81 is configured as a variable capacitance capacitor that changes capacitance according to the applied load (pressure), and in this example, it is composed of a dielectric 831, a spacer 832, and a conductive elastic body 833.

[0017] The dielectric 831 is, for example, roughly disc-shaped, with a conductive layer forming the first electrode of the variable capacitance capacitor on one of its opposing surfaces, and a conductive elastic body 833 made of conductive elastic rubber disposed on the other surface via a spacer 832 made of insulating material. The conductive elastic body 833 constitutes the second electrode of the variable capacitance capacitor.

[0018] The circuit board holder 9 comprises a circuit board storage section 91 for housing the circuit board 10 and a fitting section 92 for fitting with the holder 84 of the pressure-sensitive section 81 of the pressure-sensitive section 8 of the pressure-sensitive section 8. The fitting section 92 has a cylindrical shape with a hollow section into which the connecting section 842 of the holder 84 of the pressure-sensitive section 81 of the pressure-sensitive section 8 of the pressure-sensitive section 8 of the pressure-sensitive section 8 is inserted.

[0019] The circuit board holder 9 is prevented from moving in the direction of pressure application to the core body 3 by the case cap 21. Therefore, when the pressure detection module 8 is fitted with the circuit board holder 9, the pressure detection module 8 is prevented from moving in the axial direction within the case 2 of the electronic pen 1.

[0020] In this embodiment, as shown in Figure 9(A), the fitting portion 92 of the substrate holder 9 is provided with a ring-shaped sealing member 93, for example, made of rubber, which closes the gap between the fitting portion 92 and the inner wall of the hollow portion of the case 2. As shown in Figure 9(A), a ring-shaped groove 92a is formed on the circumferential side of the fitting portion 92 of the substrate holder 9, and the sealing member 93 is fixedly housed within this ring-shaped groove 92a.

[0021] This sealing member 93 separates the space in the hollow part of the case 2 where the printed circuit board 10 is located from the space on the opening 2a side through which the core body 3, where the pressure detection module 8 is located, protrudes. Therefore, the space where the coil 51 is located is also separated from the space on the rear end side of the electronic pen 1 by the sealing member 93.

[0022] When pressure is applied to the core 3, the pressing member 7 presses the barrier 822 of the pressure transmission member 82 in accordance with the applied pressure. The barrier 822 elastically shifts in the axial direction in accordance with the applied pressure, and this elastic shift of the barrier 822 presses the conductive elastic body 833 of the pressure-sensitive part 83. As a result, the conductive elastic body 833 and the dielectric 831, which are separated by the spacer 832, come into contact, and the contact area changes in accordance with the pressure. A capacitance corresponding to this contact area between the conductive elastic body 833 and the dielectric 831 is obtained between the first electrode and the second electrode of the pressure-sensitive part 83. In other words, the pressure can be detected from the capacitance of the variable capacitance capacitor acting as the pressure-sensitive part 83.

[0023] In the electronic pen 1 with the above configuration, the through-hole 52a of the ferrite core 52 of the coil member 5 and the through-hole of the fitting portion 61 of the coil member holder 6 communicate with each other, creating an internal space through which the core body 3 is inserted. However, this internal space is closed off by the barrier 822 of the pressure transmission member 82, and is therefore isolated from the space where the coil 51 wound around the ferrite core 52 exists. Thus, the electronic pen 1 of Patent Document 1 is protected from moisture and dust.

[0024] Japanese Patent Publication No. 2018-18149

[0025] Incidentally, one possible environment for using an electronic pen is an underwater environment where the water is deep and the pressure (water pressure) is greater than in air (for example, 30 atmospheres at a depth of 300m). In such an underwater environment, although the electronic pen 1 of Patent Document 1 has a moisture-proof and dustproof configuration, it has been found that, as mentioned above, a problem arises due to the existence of an internal space through which the core body 3 is inserted, where the through-hole 52a of the ferrite core 52 of the coil member 5 and the through-hole of the fitting portion 61 of the coil member holder 6 are in communication.

[0026] In other words, it was found that water enters the internal space of the electronic pen 1 described in Patent Document 1, and the water pressure presses against the barrier 822 of the pressure transmission member 82, which in turn presses against the conductive elastic member 833 of the pressure detection unit 81. As a result, even when no writing is taking place, it appears as if pressure is being applied, leading to what is known as ink leakage.

[0027] In view of the above-mentioned problems, this invention aims to provide an electromagnetic induction type electronic pen that can prevent moisture and dust from reaching the coil of the resonant circuit, and can also prevent ink leakage even in an underwater environment where high water pressure is applied as described above.

[0028] To solve the above problems, the present invention provides a first magnetic body around which a coil is wound; a circuit board on which a capacitor connected in parallel with the coil to form a resonant circuit is disposed; a housing having a columnar hollow space, in which the first magnetic body around which the coil is wound and the circuit board are arranged axially within the hollow space with the first magnetic body on the pen tip side, and a waterproof area for housing the first magnetic body around which the coil is wound and the circuit board in a waterproof state; a pen tip portion mounted on the pen tip side of the housing so as to be movable in the axial direction; a second magnetic body disposed on the pen tip portion so as to move with the movement of the pen tip portion to change the distance from the pen tip end of the first magnetic body; and an elastic member that generates a resistance force against movement in the direction of the first magnetic body in response to a load applied to the pen tip portion, and elastically returns the pen tip portion and the second magnetic body to their original positions on the pen tip side when the load disappears. The present invention provides an electronic pen characterized in that a sealing portion is formed in the waterproof area of ​​the housing, configured to separate the hollow space from the external space.

[0029] In the electronic pen with the above configuration, the housing has a first magnetic material around which a coil is wound and a circuit board, arranged in the axial direction with the first magnetic material on the pen tip side within a hollow space, and a waterproof area that houses the first magnetic material around which the coil is wound and the circuit board in a waterproof state. The pen tip is attached to the pen tip side of the housing in a manner that allows it to move in the axial direction, and a second magnetic material is disposed on the pen tip so as to move with the movement of the pen tip, changing the distance from the pen tip end of the first magnetic material.

[0030] Furthermore, a sealing section is formed in the waterproof area of ​​the housing, which is configured to separate the hollow space from the external space.

[0031] In the electronic pen with the above configuration, when a load is applied to the pen tip, the pen tip and the second magnetic material move toward the pen tip end of the first magnetic material, and the distance between the first magnetic material and the pen tip end of the second magnetic material changes according to the applied load. This change in distance changes the inductance of the coil, and therefore changes the resonant frequency of the resonant circuit. By detecting this change in resonant frequency on the position detection device side, the load applied to the pen tip of the electronic pen can be detected.

[0032] Furthermore, in the electronic pen with the above configuration, the sealing portion separates the hollow space inside the housing from the space outside the housing. Since there is no space for the pen body to press the conductive elastic part of the pressure detection unit, which is composed of a variable capacitance capacitor and communicates with a through-hole in the magnetic core as in Patent Document 1, ink leakage can be prevented even in underwater environments where high water pressure is applied.

[0033] This figure shows an example configuration of an embodiment of the electronic pen according to this invention. This is a cross-sectional view of three positions in the axial direction in the configuration example of Figure 1. This is an exploded perspective view showing an example configuration of an embodiment of the electronic pen according to this invention. This is a circuit diagram for position detection and pen pressure detection in a position detection device used with an embodiment of the electronic pen according to this invention. This is an example configuration of the main part of another embodiment of the electronic pen according to this invention. This is an example configuration of the main part of yet another embodiment of the electronic pen according to this invention. This is an example configuration of yet another embodiment of the electronic pen according to this invention. This is an example configuration of the pen tip side of a conventional electronic pen configuration example. This is an example configuration of the rear end side of a conventional electronic pen configuration example.

[0034] Hereinafter, embodiments of the electronic pen according to this invention will be described with reference to the figures.

[0035] Figure 1 shows an example of the configuration of the electronic pen 100 according to the embodiment. Figure 1(A) shows the overall appearance of the electronic pen 100, and Figure 1(B) is an enlarged longitudinal cross-sectional view of the electronic pen 100. Figure 2(A) is a cross-sectional view taken along line A-A in Figure 1(B), Figure 2(B) is a cross-sectional view taken along line B-B in Figure 1(B), and Figure 2(C) is a cross-sectional view taken along line C-C in Figure 1(B). Figure 3 is an exploded perspective view of the components of the electronic pen 100 according to the embodiment.

[0036] As shown in Figures 1(A), (B) and 2, the electronic pen 100 of this embodiment is configured with an external housing 101 placed over the outside of an internal housing 102. The housing of claim 1 of the claims is composed of the internal housing 102. As shown in Figures 1(A) and (B), the pen tip portion 103 is attached to the pen tip side of the electronic pen 100 in a manner that allows it to move in the axial direction, and the rear end side opposite to the pen tip side is closed by an end cap 104.

[0037] In this embodiment, the external housing 101 has a cylindrical shape with a constant outer and inner diameter. In this example, the external housing 101 is made of resin.

[0038] In this example, the internal housing 102 is also made of resin. The internal housing 102 has a large diameter portion 102a in the axial direction, excluding the pen tip side, which has an outer diameter slightly smaller than the inner diameter of the external housing 101. On the pen tip side of the internal housing 102, as shown in Figures 1(B) and 2(A), a medium diameter portion 102b is formed, which has a diameter that is a predetermined size smaller than the inner diameter of the external housing 101, taking into account the mounting of the pen tip portion 103. Furthermore, on the pen tip side of this medium diameter portion 102b, as shown in Figures 1(B) and 3, a small diameter portion 102c is formed, which has an even smaller diameter than the medium diameter portion 102b.

[0039] In this example, the pen tip portion 103 is made of an elastic material, such as resin, and has a tapered shape that becomes narrower as it approaches the tip, as shown in Figures 1(A), (B) and 3. In this embodiment, the rear end of the pen tip portion 103, opposite to the tip in the axial direction, is a large-diameter portion 103a having an outer diameter equal to the outer diameter of the outer housing 101.

[0040] The pen tip portion 103 is provided with a recess 103b that opens on the side of the large diameter portion 103a. This recess 103b is sized to accommodate the small diameter portion 102c and the medium diameter portion 102b of the internal housing 102, and is also formed to accommodate a magnetic member MG made of ferrite, for example, as an example of a second magnetic material (soft magnetic material) described later, and a coil spring member 105, as an example of an elastic material.

[0041] The pen tip portion 103 is provided with a ring-shaped annular portion 103c at the rear end of the large-diameter portion 103a, as shown in Figure 1(B), which has an outer diameter smaller than the inner diameter of the outer housing 101 and an inner diameter larger than the outer diameter of the medium-diameter portion 102b of the inner housing 102. In this example, extension portions 103d and 103e are formed on the ring-shaped annular portion 103c at positions 180 degrees apart from each other, as shown in Figures 1(B) and 3, extending further in the axial direction from the ring-shaped annular portion 103c. Engaging projections 103dt and 103et are formed at the tips of these extension portions 103d and 103e in the extension direction, projecting toward the center of the inner housing 102 in a direction perpendicular to the axial direction.

[0042] On the other hand, at positions 180 degrees apart from each other on the outer circumferential surface of the large-diameter portion 102a of the inner housing 102 on the pen tip side, axial grooves 102d and 102e are provided, as shown in Figures 1(B) and 3, to accommodate the extended portions 103d and 103e of the pen tip portion 103. As shown in Figures 1(B) and 3, the grooves 102d and 102e include, in the axial direction, deep groove portions 102da and 102ea with a depth to accommodate the engaging projections 103dt and 103et of the extended portions 103d and 103e, and shallow groove portions 102db and 102eb with a depth to accommodate the portions of the extended portions 103d and 103e other than the engaging projections 103dt and 103et.

[0043] As shown in Fig. 1(B), the pen tip portion 103 is mounted so as to cover the pen tip side of the inner housing 102. At this time, as shown in Fig. 1(B), the middle diameter portion 102b and the small diameter portion 102c of the inner housing 102 are housed in the recess 103b of the pen tip portion 103, and the extending portions 103d and 103e of the pen tip portion 103 are mounted so as to be housed in the recess grooves 102d and 102e of the large diameter portion 102a of the inner housing 102.

[0044] As described above, since the extending portions 103d and 103e are made of a resin having elasticity, the pen tip portion 103 can be elastically displaced in a direction perpendicular to the axial direction. Therefore, when the pen tip portion 103 is placed so as to cover the pen tip side of the inner housing 102, the engaging protrusions 103dt and 103et of the extending portions 103d and 103e climb over the shallow groove portions 102db and 102ed of the recess grooves 102d and 102e and advance to reach the deep groove portions 102da and 102ea. Then, as shown in Fig. 1(B), the engaging protrusions 103dt and 103et of the extending portions 103d and 103e engage with the engaging step portions formed at the boundaries between the deep groove portions 102da and 102ea and the shallow groove portions 103db and 103ed, and the pen tip portion 103 is in a state where it does not detach from the pen tip side of the inner housing 102.

[0045] Further, in a state where the outer housing 101 covers the inner housing 102, as shown in Fig. 1(B), most of the ring-shaped annular portion 103c and the extending portion 103d of the pen tip portion 103 are in a state of being present between the large diameter portion 102a of the inner housing 102 and the outer housing 101, and the pen tip portion 103 will not detach from the electronic pen 100.

[0046] In this case, in the electronic pen 100 of this embodiment, the axial lengths of the deep grooves 102da and 102ea and the shallow grooves 102db and 102eb of the grooves 102d and 102e, and the axial lengths of the extended portions 103d and 103e of the pen tip portion 103 are selected so that when the engaging projections 103dt and 103et of the extended portions 103d and 103e are engaged with the engaging steps of the grooves 102d and 102e, a gap of a predetermined distance d is created between the outer housing 101 and the large diameter portion 103a of the pen tip portion 103, as shown in Figures 1(A) and (B). The pen tip portion 103 becomes movable toward the rear end in the axial direction by this predetermined distance d. This predetermined distance d is selected to be greater than or equal to the distance the pen tip 103 moves in the axial direction when a load (pen pressure) within the detection range is applied to the pen tip 103.

[0047] In this embodiment, as shown in Figure 1(B), a recessed hole 103ba is formed at the bottom of the recess 103b of the pen tip portion 103 on the pen tip side, with a diameter smaller than the small diameter portion 102c of the internal housing 102 on the pen tip side. In this example, a cylindrical magnetic member MG is housed in this recessed hole 103ba. As shown in Figure 1(B), the magnetic member MG is housed facing the tip surface of the small diameter portion 102c of the internal housing 102, and an elastic member, a coil spring member 105 made of metal in this example, is provided between the tip surface of the small diameter portion 102c of the internal housing 102 and the magnetic member MG. The elastic force of this coil spring member 105 always acts to separate the magnetic member MG from the tip surface of the small diameter portion 102c of the internal housing 102, and acts as a resistance force when the pen tip portion 103 moves in response to the applied load.

[0048] Therefore, when no writing pressure is applied to the pen tip portion 103 mounted on the pen tip side of the inner housing 102, the engaging protrusions 103dt and 103et of the extending portions 103d and 103e are engaged with the engaging step portions of the concave grooves 102d and 102e as shown in FIG. 1(B) due to the elastic force of the coil spring member 105. When writing pressure is applied to the pen tip portion 103, the pen tip portion 103 moves and displaces toward the rear end against the elastic force of the coil spring member 105 by an amount corresponding to the magnitude of the writing pressure. When the writing pressure disappears, the engaging protrusions 103dt and 103et of the extending portions 103d and 103e return to the state of being engaged with the engaging step portions of the concave grooves 102d and 102e due to the elastic force of the coil spring member 105. That is, the coil spring member 105 acts as an elastic member for elastic return of the pen tip portion 103.

[0049] Needless to say, the elastic member for elastic return of the pen tip portion 103 is not limited to the coil spring member 105 as in this example.

[0050] The inner housing 102 has a columnar hollow space 102f with a predetermined diameter inside. As shown in FIG. 1(B), a ferrite core 107 (see FIG. 3), which is a first magnetic body around which the coil 106 is wound, and a substrate holder 108 (see FIG. 3) are housed in the hollow space 102f of the inner housing 102 in a state where the ferrite core 107 is arranged in the axial direction with the pen tip side and is immovable in the axial direction as will be described later.

[0051] As shown in FIG. 1(B), a circuit board 109 (see FIG. 3) is held by the substrate holder 108. A capacitor 109C (see FIG. 3) that is electrically connected to the coil 106 to form a resonance circuit is provided on the circuit board 109. The upper part of the circuit board 109 held by the substrate holder 108 is covered with a substrate holder cover (see FIG. 3) 110.

[0052] In this embodiment, as shown in Figure 1(B), a ferrite core holder 111 (see Figure 3) is attached to the pen tip side of the substrate holder 108. The portion of the ferrite core 107 at the rear end where the coil 106 is not wound (referred to as the unwound coil portion) is fitted into this ferrite core holder 111, thereby holding the ferrite core 107 around which the coil 106 is wound. As a result, in this embodiment, the ferrite core 107 around which the coil 106 is wound and the substrate holder 108 can be treated as an integrated component.

[0053] In this embodiment, the pen tip end of the internal housing 102 has a wall portion with a through hole 102g having a diameter smaller than the hollow space 102f. The ferrite core 107 has a through hole 107a having a diameter equal to or slightly larger than the diameter of the through hole 102g.

[0054] On the other hand, as shown in Figures 1(B) and 3, the pen tip portion 103 has a rod-shaped portion 103f that extends axially from the center of the bottom of the recessed hole portion 103ba of the recess 103b. This rod-shaped portion 103f has a diameter smaller than the diameter of the through hole 102g of the internal housing 102, and is of a length that allows it to be inserted through the through hole 102g of the internal housing 102 to partway through the through hole 107a of the ferrite core 107 when the pen tip portion 103 is mounted over the pen tip side of the internal housing 102.

[0055] The aforementioned magnetic member MG has a through hole MGa through which the rod-shaped portion 103f is inserted. Furthermore, the coil winding diameter of the coil spring member 105 is larger than the diameter of the rod-shaped portion 103f and smaller than the outer diameter of the magnetic member MG. Therefore, in this embodiment, as shown in Figure 1(B), the pen tip portion 103 is mounted on the internal housing 102 so as to be movable in the axial direction, with the rod-shaped portion 103f inserted through the magnetic member MG and the coil spring member 105, and inserted through the through hole 102g of the internal housing 102 to partway through the through hole 107a of the ferrite core 107. Due to the presence of this rod-shaped portion 103f, the direction of movement when writing pressure is applied to the pen tip portion 103 is almost along the axial direction, and it is possible to prevent the pen tip portion 103 from rattling in a direction intersecting the axial direction.

[0056] In this embodiment, as shown in Figure 1(B), the tip of the ferrite core 107 abuts against the wall of the pen tip in the hollow space 102f of the internal housing 102 via a gasket 112 (see Figure 3) made of, for example, an elastic material. The gasket 112 has a through hole through which the rod-shaped portion 103f is inserted.

[0057] As shown in Figure 1(B), an O-ring 113 (see Figure 3), which is an example of a sealing member, is provided on the outer circumference of the non-winding portion of the ferrite core 107 on the pen tip side. This O-ring 113 seals the gap between the inner wall surface of the inner housing 102 and the non-winding portion of the ferrite core 107 on the pen tip side. In other words, in this embodiment, the O-ring 113 seals the space where the coil 106 exists and the external space through the through-hole 102g of the inner housing 102.

[0058] Furthermore, the sealing member is not limited to the O-ring 113; any material that can block the space where the coil 106 is located from the external space through the through-hole 102g of the internal housing 102 may be used.

[0059] Furthermore, the gasket 112 also plays a sealing role, separating the space where the coil 106 is located from the external space through the through-hole 102g of the internal housing 102. In other words, in this embodiment, sealing is provided by both the O-ring 113 and the gasket 112, resulting in a stronger seal.

[0060] Furthermore, in this embodiment, the rear end of the through-hole 107a of the ferrite core 107 around which the coil 106 is wound is sealed without any gaps by an elastic member, in this example, an elastic rubber member 114. Due to the presence of this elastic rubber member 114, even though the ferrite core 107 has a through-hole 107a, the space on the pen tip side of the through-hole 107a and the space on the rear end side are separated.

[0061] Furthermore, in this embodiment, the rear end of the substrate holder 108, which is provided on the rear end side of the ferrite core 107 in the hollow space 102f of the internal housing 102, is sealed without gaps by an ultraviolet-curable adhesive portion 115 (see Figure 3), as shown in Figures 1(B) and 2(B). This adhesive portion 115 has the function of a position regulating member to prevent the ferrite core 107 and the substrate holder 108 from moving in the axial direction within the hollow space 102f of the internal housing 102, and also has the function of a sealing member that separates the hollow space 102f of the internal housing 102 from the space outside it.

[0062] The member that positions and seals the rear end of the through hole 107a of the ferrite core 107 is not limited to the ultraviolet-curable adhesive portion 115 as in this example, but other adhesives or various other members such as elastic rubber members may be used.

[0063] As described above, in the hollow space 102f of the internal housing 102, the area where the ferrite core 107 around which the coil 106 is wound and the circuit board 109 are housed is sealed on the pen tip side with an O-ring 113 and a gasket 112, and on the rear end side with an adhesive portion 115, thus becoming a waterproof area that houses the ferrite core 107 around which the coil 106 is wound and the circuit board 109 in a waterproof state.

[0064] In this embodiment, as shown in Figures 1(A) and (B), the end cap 104 is attached to the rear end of the outer housing 101, thereby closing not only the opening at the rear end of the outer housing 101 but also the opening at the rear end of the hollow space of the inner housing 102. That is, as shown in Figures 1(B) and 3, the end cap 104 has a cap top portion 104a with an outer diameter equal to the outer diameter of the outer housing 101, an outer housing closing portion 104b with an outer diameter slightly smaller than the inner diameter of the outer housing 101, and an inner housing closing portion 104c (see Figure 2(C)) which is slightly smaller than the diameter of the hollow space 102f of the inner housing 102.

[0065] As shown in Figure 1(B), the end cap 104 is installed such that the outer housing closing portion 104b is inserted into the portion of the hollow space of the outer housing 101 that is further to the rear than the rear end of the inner housing 102, and the inner housing closing portion 104c is inserted into the portion of the hollow space 102f of the inner housing 102 that is further to the rear than the UV-curable adhesive portion 115.

[0066] In this embodiment, the space between the outer casing 101 and the inner casing 102 is not sealed. As a result, water can enter the space between the outer casing 101 and the inner casing 102, and if the electronic pen 100 of this embodiment is used in a place with deep water, there is a risk that a relatively large pressure will be exerted on the space between the outer casing 101 and the inner casing 102. To avoid this problem, in the electronic pen 100 of this embodiment, as shown in Figures 1(B) and 3, through holes 101a and 101b for ventilation and water passage are provided in the outer casing 101 at positions 180 degrees apart from each other. Air and water passing through the gap between the outer casing 101 and the inner casing 102 are discharged to the outside through these through holes 101a and 101b. Therefore, these ventilation and water passage through holes 101a and 101b reduce the pressure exerted on the space between the outer casing 101 and the inner casing 102.

[0067] [Circuit configuration for position detection and pen pressure detection in a position detection device used with the electronic pen 100] Next, an example of the circuit configuration and operation of a position detection device 300 that detects the indicated position by the electronic pen 100 and the pen pressure applied to the electronic pen 100 will be described with reference to Figure 4.

[0068] As shown in Figure 4, in the electronic pen 100, one end of the coil 106 and the other end are connected to the capacitor 109C to form a resonant circuit 100R. The distance between the tip of the ferrite core 107 around which the coil 106 is wound and the magnetic member MG changes in accordance with the writing pressure applied to the pen tip 103, causing the coil 106 to operate as a variable inductance. Therefore, the resonant frequency of the resonant circuit 100R changes in accordance with the writing pressure applied to the pen tip 103. The position detection device 300 detects the writing pressure applied to the pen tip 103 of the electronic pen 100 by detecting this change in resonant frequency.

[0069] In this embodiment, the electromagnetic induction type position detection device 300 transmits a signal to the electronic pen 100 via electromagnetic induction coupling, and the electronic pen 100 feeds back the signal received from the position detection device 300 via the resonant circuit 100R.

[0070] The position detection device 300 receives a feedback signal from the resonant circuit 100R of the electronic pen 100 via electromagnetic induction coupling. From the position on the sensor where the received signal is detected, it detects the position on the sensor indicated by the electronic pen 100. It also detects a change in the resonant frequency by detecting a change in the phase of the signal received from the resonant circuit 100R of the electronic pen 100 via electromagnetic induction coupling, thereby detecting the writing pressure applied to the pen tip 103 of the electronic pen 100.

[0071] The position detection device 300 has a position detection sensor 310 formed by stacking an X-axis loop coil group 311 and a Y-axis loop coil group 312 to create a position detection coil. The position detection device 300 is also provided with a selection circuit 313 to which the X-axis loop coil group 311 and the Y-axis loop coil group 312 are connected. The selection circuit 313 sequentially selects the loop coil to be activated from the two loop coil groups 311 and 312.

[0072] The position detection device 300 also includes an oscillator 301, a current driver 302, a switching connection circuit 303, a receiving amplifier 304, a position detection circuit 305, a pen pressure detection circuit 306, and a processing control unit 307. The processing control unit 307 controls the selection of the loop coil in the selection circuit 313, the switching of the switching connection circuit 303, and the processing timing in the position detection circuit 305 and the pen pressure detection circuit 306.

[0073] The oscillator 301 generates an AC signal with frequency f0. The oscillator 301 then supplies the generated AC signal to the current driver 302 and the pressure sensitivity detection circuit 306. The current driver 302 converts the AC signal supplied from the oscillator 301 into current and sends it to the switching connection circuit 303. The switching connection circuit 303, under control from the processing control unit 307, switches the connection destination (transmitter terminal T, receiver terminal R) to which the loop coil selected by the selection circuit 313 is connected. Of these connection destinations, the current driver 302 is connected to the transmitter terminal T, and the receiver amplifier 304 is connected to the receiver terminal R.

[0074] The induced voltage generated in the loop coil selected by the selection circuit 313 is sent to the receiving amplifier 304 via the selection circuit 313 and the switching connection circuit 303. The receiving amplifier 304 amplifies the induced voltage supplied from the loop coil and sends it to the position detection circuit 305 and the pen pressure detection circuit 306.

[0075] Each loop coil in the X-axis loop coil group 311 and the Y-axis loop coil group 312 is induced by radio waves transmitted from the electronic pen 100. The position detection circuit 305 detects the induced voltage generated in the loop coils, i.e., the received signal, converts the detected output signal into a digital signal, and outputs it to the processing control unit 307. The processing control unit 307 calculates the coordinate values ​​of the indicated positions in the X-axis and Y-axis directions of the electronic pen 100 based on the digital signals from the position detection circuit 305, i.e., the voltage levels of the induced voltages generated in each loop coil.

[0076] Meanwhile, the pressure detection circuit 306 synchronously detects the output signal of the receiving amplifier 304 with the AC signal from the oscillator 301 to obtain a signal with a level corresponding to the phase difference (frequency shift) between them, converts this signal corresponding to the phase difference (frequency shift) into a digital signal, and outputs it to the processing control unit 307. The processing control unit 307 detects the pressure applied to the electronic pen 100 based on the level of the digital signal from the pressure detection circuit 306, that is, the signal corresponding to the phase difference (frequency shift) between the transmitted radio wave and the received radio wave.

[0077] As described above, in the electronic pen 100 of the above embodiment, by housing the magnetic member MG in the pen tip portion 103, the magnetic member MG moves in the axial direction together with the pen tip portion 103 which moves in accordance with the applied writing pressure, thereby changing the distance between the tip portion of the ferrite core 107 around which the coil 106 is wound and the magnetic member MG, and thus the inductance of the coil constituting the resonant circuit is changed in accordance with the writing pressure applied to the pen tip portion 103.

[0078] Therefore, according to the electronic pen 100 of this embodiment, as described in Patent Document 1 at the beginning, it is not necessary to provide a through hole in the ferrite core and transmit the pen pressure to the pen pressure detection element provided on the rear end side of the ferrite core by inserting the pen through this through hole. The through hole 107a of the ferrite core 107 is closed by the elastic rubber member 114.

[0079] Furthermore, on the pen tip side of the internal housing 102 of the electronic pen 100 in this embodiment, a sealing member, in this example an O-ring 113 and a gasket 112, is provided to eliminate the gap between the inner wall surface and the ferrite core 107, thereby separating the external space on the pen tip side of the ferrite core 107 from the space where the coil 106 wound around the ferrite core 107 and the circuit board 109 are located.

[0080] Furthermore, at the rear end of the internal housing 102 of the electronic pen 100 in this embodiment, the rear end of the hollow space 102f of the internal housing 102 is sealed by a sealing member, in the above example, by an ultraviolet-curing adhesive portion 115. Thus, the space where the coil 106 wound around the ferrite core 107 and the circuit board 109 exist is separated from the external space at the rear end of the internal housing 102.

[0081] Therefore, in this embodiment of the electronic pen 100, the coil 106 and the circuit board 109 can be made waterproof and dustproof. Furthermore, in this embodiment of the electronic pen 100, since the pressure detection configuration using the variable inductance described above is used, there is no risk of pressure being transmitted to the pressure detection element due to water pressure, as in the electronic pen 1 of Patent Document 1. Thus, with this embodiment of the electronic pen 100, even in places where the water depth is great and water pressure is great, the waterproof effect is maintained and so-called ink leakage does not occur.

[0082] [Other Embodiments or Modifications] In the electronic pen 100 of the above embodiment, in order to make the axial movement in response to the writing pressure applied to the pen tip portion 103 smooth, a rod-shaped portion 103f is provided in the recess 103b of the pen tip portion 103, a through hole 102g is provided on the end face of the internal housing 102 on the pen tip side, and a through hole 107a is also provided in the ferrite core 107, and the rear end of the rod-shaped portion 103f is inserted into the through hole 107a of the ferrite core 107 via the magnetic member MG, the coil spring member 105, and the through hole 102g.

[0083] However, the configuration in which the pen tip portion 103 moves in the axial direction in response to the writing pressure applied to the pen tip portion is not limited to this configuration.

[0084] <Another Example of the First> Figure 5 shows the main part of the pen tip side of an electronic pen 100A having a configuration of another example of the first, in which the pen tip portion 103 moves in the axial direction in accordance with the writing pressure applied to the pen tip portion. In Figure 5, the same reference numerals are used for components that are the same as in the above-described embodiment, and their detailed description is omitted.

[0085] In this first example of an electronic pen 100A, the parts that differ from the electronic pen 100 of the embodiment described above are the internal housing 102A, the pen tip portion 103A, and the ferrite core 107A. The rest of the configuration is the same as in the embodiment described above.

[0086] As shown in Figure 5, the internal housing 102A does not have a through hole at the end face on the pen tip side, and the pen tip side of the hollow space 102Af of the internal housing 102A is closed off by the end face on the pen tip side. In other words, the pen tip side of the hollow space 102Af of the internal housing 102A is sealed by being closed off by the end face on the pen tip side, and the hollow space 102Af of the internal housing 102A is isolated from the external space on the pen tip side of the internal housing 102.

[0087] In this first alternative example, the ferrite core 107A is configured without through holes. Also, in this first alternative example, as shown in Figure 5, an O-ring to eliminate the gap between the ferrite core 107A and the inner wall surface of the internal housing 102A, and a gasket as a packing member are unnecessary and not provided.

[0088] In this example, a rod-shaped portion 102h is formed on the pen tip side of the internal housing 102A, extending axially from the center of the outer surface of the end face on the pen tip side toward the recess 103Ab of the pen tip portion 103A. The other configurations of the internal housing 102A are the same as those of the internal housing 102 of the electronic pen 100 described above.

[0089] In this example, the pen tip portion 103A does not have the rod-shaped portion 103f of the pen tip portion 103 in the embodiment described above. Instead, at the bottom of the recessed hole portion 103Aba in the recess 103Ab of the pen tip portion 103A in this example, a recessed hole portion 103Abb is provided, into which the rod-shaped portion 102h formed in the internal housing 102A is inserted, passing through the coil spring member 105 and the magnetic member MG.

[0090] In this case, the depth (length in the axial direction) of the recessed portion 103Abb is such that, when no writing pressure is applied as shown in Figure 5, a space is created between the tip of the rod-shaped portion 102h and the bottom of the recessed portion 103Abb, and when writing pressure is applied to the pen tip portion 103A, the pen tip portion 103A is able to move toward the rear end. The other configurations of the pen tip portion 103A are the same as those of the pen tip portion 103 of the electronic pen 100 described above.

[0091] This first alternative example of the electronic pen 100A also has the same effects and advantages as the electronic pen 100 of the embodiment described above. In this first alternative example of the electronic pen 100A, the pen tip side of the internal housing 102A is closed with an end face that does not have a through hole, thereby achieving sealing that blocks the space between the hollow space 102Af and the external space on the pen tip side. Therefore, in this first alternative example of the electronic pen 100A, an O-ring to eliminate the gap between the ferrite core 107A and the inner wall surface of the internal housing 102A, and a gasket as a packing member are not required, as in the embodiment described above. Furthermore, it has the advantage that a ferrite core without a through hole can be used as the ferrite core 107A.

[0092] <Second Other Example> Figure 6 shows the main part of the pen tip side of an electronic pen 100B having a configuration of a second other example in which the pen tip portion 103 moves in the axial direction in accordance with the writing pressure applied to the pen tip portion. In Figure 6 as well, the same reference numerals are used for the same components as in the above-described embodiment, and their detailed description is omitted.

[0093] In this second example of the electronic pen 100B, the parts that differ from the electronic pen 100 of the above-described embodiment are the internal housing 102B, the pen tip portion 103B, the ferrite core 107B, and the magnetic member MGB. The rest of the configuration is the same as in the above-described embodiment.

[0094] As shown in Figure 6, the internal housing 102B of this second example of the electronic pen 100B also does not have a through hole at the end face on the pen tip side, and the pen tip side of the hollow space 102Bf of the internal housing 102B is closed off by the end face on the pen tip side. In other words, the pen tip side of the hollow space 102Bf of the internal housing 102B is sealed by the end face on the pen tip side, and the hollow space 102Bf of the internal housing 102B is isolated from the external space on the pen tip side of the internal housing 102. Furthermore, the internal housing 102B of this second example of the electronic pen 100B does not have the rod-shaped portion 102h of the first example.

[0095] The ferrite core 107B in this second example, like the ferrite core 107A in the first example described above, is configured without through holes. Also, in this second example, as shown in Figure 6, an O-ring to eliminate the gap between the ferrite core 107B and the inner wall surface of the internal housing 102B, and a gasket as a packing member are unnecessary and not provided.

[0096] In this example, the recess 103Bb of the pen tip portion 103B does not have the rod-shaped portion 103f that is provided in the recess 103b of the electronic pen 100 in the above-described embodiment, and the magnetic member MGB is housed in the recessed hole portion 103Bba. In this second other example, the magnetic member MGB does not need to have a through hole. However, in this example, the magnetic member MGB is provided with a recess MGBa for housing and locking one end of the coil spring member 105.

[0097] In the example shown in Figure 6, a recess MGBa is provided only on the magnetic member MGB side for accommodating and locking the end of the coil spring member 105. However, a recess for accommodating and locking the end of the coil spring member 105 may also be provided on the pen tip end face of the internal housing 102B.

[0098] In the example shown in Figure 6, the recesses provided on the end face of the pen tip side of the magnetic member MGB and the internal housing 102B are not essential and may be omitted.

[0099] This second example of the electronic pen 100B also has the same effects and advantages as the electronic pen 100 of the embodiment described above. In this second example of the electronic pen 100B, the pen tip side of the internal housing 102B is closed with an end face that does not have a through hole, thereby achieving sealing that blocks the space between the hollow space 102Bf and the external space on the pen tip side. This eliminates the need for an O-ring to eliminate the gap between the ferrite core 107B and the inner wall surface of the internal housing 102B, and a gasket as a packing member. Furthermore, this configuration allows for the use of a ferrite core without a through hole as the ferrite core 107B, and also allows for the use of a magnetic member without a through hole as the magnetic member MGB.

[0100] <Third Other Example> In the above embodiment, an external housing 101 is provided on the outside of the internal housing 102, and an end cap 104 is provided to close the opening on the rear end side of the external housing 101. However, it is also possible to have a configuration in which neither the external housing 101 nor the end cap 104 is provided.

[0101] Figure 7 is a diagram illustrating the configuration of the electronic pen 100C as described above. Figure 7(A) is a longitudinal cross-sectional view of the electronic pen 100C, and Figure 7(B) is a cross-sectional view taken along line D-D in Figure 7(A). In this example of Figure 7, the same reference numerals are used for components identical to those in the above-described embodiment, and their detailed descriptions are omitted.

[0102] In this third example of the electronic pen 100C, the differences from the electronic pen 100 of the above-described embodiment are that the external housing 101 and end cap 104 are not provided, and the internal housing 102C, pen tip portion 103C, ferrite core 107C, and magnetic member MGC are different. Otherwise, the configuration is the same as in the above-described embodiment.

[0103] In this third alternative example, the external housing 101 and end cap 104 are not provided, so the internal housing 102C is referred to as the pen housing 102C. As shown in Figure 7(A), in this third alternative example, similar to the second alternative example, the pen housing 102C of the electronic pen 100C does not have a through hole at the end face on the pen tip side, and the pen tip side of the hollow space 102Cf of the pen housing 102C is closed off by the end face on the pen tip side. In other words, the pen tip side of the hollow space 102Cf of the pen housing 102C is separated from the external space on the pen tip side of the pen housing 102 by the end face on the pen tip side, and there is no need to provide a sealing member such as an O-ring separately.

[0104] In this third example, the hollow space 102Cf of the pen housing 102C is filled with resin molding. In this case, the resin molding may be applied in advance to at least the portion of the circuit board 109.

[0105] Furthermore, in this third example, the rear end of the hollow space 102Cf of the pen housing 102C is sealed without gaps by an ultraviolet-curable adhesive portion 115C, as shown in Figure 7(A). This adhesive portion 115C functions as a position regulating member to prevent the ferrite core 107C and the substrate holder 108 from moving axially within the hollow space 102Cf of the pen housing 102C, and also functions as a sealing member to separate the hollow space 102Cf of the pen housing 102C from the space outside it.

[0106] The member used to seal the rear end of the hollow space 102Cf of the pen housing 102C is not limited to the UV-curable adhesive portion 115 as in this example, but may also be other adhesives or various other materials such as elastic rubber members.

[0107] This third example of the ferrite core 107C, like the ferrite cores 107A and 107B of the first and second examples described above, is configured without through holes.

[0108] In this example, the recess 103Cb of the pen tip portion 103C does not have the rod-shaped portion 103f that is provided in the recess 103b of the electronic pen 100 in the above-described embodiment, and the magnetic member MGC is housed in the recessed hole portion 103Cba. In this third other example, the magnetic member MGB is provided with a recess MGCa for housing and locking a part of the coil spring member 105C.

[0109] In this third example, a recess may also be provided on the end face of the pen casing 102C on the pen tip side to accommodate and lock the end of the coil spring member 105C.

[0110] In this third example, the axial length of the large-diameter portion 103Ca at the rear end of the pen tip portion 103C is longer than in the previously described embodiment. The pen tip portion 103C is then fitted onto the pen tip side of the pen housing 102C by inserting the pen tip side of the pen housing 102C into the portion of the large-diameter portion 103Ca in the recess 103Cb of the pen tip portion 103CC.

[0111] In this case, the rear end of the large-diameter portion 103Ca of the pen tip portion 103C is provided with multiple inward-facing protrusions, specifically four in this example, as shown in Figure 7(B): 103Ct1, 103Ct2, 103Ct3, and 103Ct4. The circumferential surface of the pen tip portion of the pen housing 102C that is inserted into the recess 103Cb of the pen tip portion 103C is provided with recesses 102Ca, 102Cb, 102Cc, and 102Cd, which are formed to accommodate the four inward-facing protrusions 103Ct1, 103Ct2, 103Ct3, and 103Ct4. The axial length of these recesses 102Ca, 102Cb, 102Cc, and 102Cd is set to take into account the distance the pen tip portion 103C moves axially in response to the applied writing pressure.

[0112] Furthermore, when the pen tip portion 103C is attached to the pen tip side of the pen housing 102C, an axial slit is formed on the rear end side of the large diameter portion 103Ca of the pen tip portion 103C so that the inward-facing protrusions 103Ct1, 103Ct2, 103Ct3, and 103Ct4 can be elastically displaced outward.

[0113] This third example of the electronic pen 100C also has the same effects and advantages as the electronic pen 100 of the embodiment described above. Furthermore, this third example of the electronic pen 100C has the same effects and advantages as the electronic pen 100B of the second example described above.

[0114] As shown in Figure 7(A), there is a gap between the circumferential surface of the pen casing 102C on the pen tip side and the inner wall surface of the large-diameter portion 103Ca of the pen tip portion 103C. This gap serves the function of ventilation and water passage.

[0115] [Other Embodiments or Modifications] It goes without saying that the configuration in which the pen tip portions 103, 103A, and 103B are connected to the internal housings 102, 102A, and 102B while maintaining a stroke for detecting writing pressure in at least the axial direction is not limited to the configuration described above, in which extension portions 103d and 103e are provided on the pen tip portions 103, 103A, and 103B, and grooves 102d and 102e are provided on the internal housings 102, 102A, and 102B. In short, any configuration is acceptable as long as the pen tip portions 103, 103A, and 103B are locked to the internal housings 102, 102A, and 102B in a state that allows them to move in the axial direction.

[0116] 100, 100A, 100B... Electronic pen, 101... External housing, 102, 102A, 102B... Internal housing, 102f, 102Af, 102Bf... Hollow space, 102h... Rod-shaped part, 103, 103A, 103B... Pen tip part, 103b, 103Ab, 103Bb... Recess, 103d, 103e... Extension part, 103f... Rod-shaped part, 104... End cap, 105... Carp 106...coil, 107, 107A, 107B...ferrite core, 108...substrate holder, 109...circuit board, 109C...capacitor, 110...substrate holder cover, 111...ferrite core holder, 112...gasket, 113...O-ring, 114...elastic rubber member, 115...adhesive part, MG, MGB...magnetic member, MGa...through hole

Claims

1. A first magnetic body around which a coil is wound; a circuit board on which a capacitor connected in parallel with the coil to form a resonant circuit is disposed; a housing having a columnar hollow space, in which the first magnetic body around which the coil is wound and the circuit board are arranged axially with the first magnetic body on the pen tip side, and a waterproof area for housing the first magnetic body around which the coil is wound and the circuit board in a waterproof state; a pen tip portion mounted on the pen tip side of the housing so as to be movable in the axial direction; a second magnetic body disposed on the pen tip portion so as to move with the movement of the pen tip portion to change the distance from the pen tip end of the first magnetic body; and an elastic member that generates a resistance force against movement in the direction of the first magnetic body in response to a load applied to the pen tip portion, and elastically returns the pen tip portion and the second magnetic body to their original positions on the pen tip side when the load disappears. An electronic pen characterized in that a sealing portion is formed in the waterproof area of ​​the housing, configured to block the hollow space from the external space.

2. The electronic pen according to claim 1, wherein the pen tip portion has a rod-shaped portion extending toward the housing in the axial direction at the center of the cross-section of the pen tip portion, the housing has an opening on the pen tip side through which the rod-shaped portion is inserted, the first magnetic material has an axial recessed hole into which the rod-shaped portion is inserted in a state in which it can move in the axial direction, the second magnetic material and the elastic member have through holes through which the rod-shaped portion is inserted, and when the pen tip portion is attached to the pen tip side of the housing, the rod-shaped portion through which the second magnetic material and the elastic member are inserted is inserted into the recessed hole of the first magnetic material through the opening of the housing.

3. An extension portion is provided on the side opposite to the tip of the pen tip portion, extending axially along the outer shape of the pen tip side of the housing, and a second engaging portion is formed on the extension portion that engages with a first engaging portion provided on the outer peripheral wall of the pen tip side of the housing, and the pen tip portion is configured not to detach from the pen tip side of the housing by the engagement of the first engaging portion and the second engaging portion, as described in claim 1.

4. The electronic pen according to claim 3, characterized in that the housing is an internal housing, an external housing is provided on the outside of the internal housing, and the extension portion of the pen tip is arranged in the gap between the external housing and the internal housing on the pen tip side.

5. The electronic pen according to claim 2, characterized in that the sealing portion comprises a first sealing portion that isolates the hollow space from the external space on the pen tip side and a second sealing portion that isolates the hollow space from the external space on the rear end side.

6. The electronic pen according to claim 5, characterized in that the first sealing portion includes a sealing member that seals the gap between the portion of the first magnetic material closer to the pen tip than the winding portion of the coil and the inner wall surface of the housing.

7. The electronic pen according to claim 6, characterized in that the sealing member is composed of an O-ring made of an elastic material.

8. The electronic pen according to claim 6, characterized in that the sealing member comprises: an O-ring made of an elastic material disposed between the outer periphery of the first magnetic material in the direction along the axial direction, which is the portion of the first magnetic material closer to the pen tip than the winding portion of the coil, and a surface of the inner wall surface of the housing in the direction along the axial direction; and a gasket made of an elastic material disposed between the tip end face of the first magnetic material on the pen tip side in a direction perpendicular to the axial direction and a surface of the inner wall surface of the housing facing the tip end face in a direction perpendicular to the axial direction.

9. The electronic pen according to claim 5, characterized in that the second sealing portion is composed of a member that completely closes the rear end side of the hollow space without any gaps.

10. The electronic pen according to claim 9, characterized in that the blocking member is made of adhesive.

11. The electronic pen according to claim 10, characterized in that the adhesive is an ultraviolet-curing adhesive.

12. The electronic pen according to claim 1, characterized in that the housing has a wall portion that closes the pen tip side, and the sealing portion is configured by filling the rear end side of the hollow space with a member that completely closes the gap.

13. The electronic pen according to claim 12, characterized in that the elastic member is disposed between the wall portion that closes the pen tip side and the second magnetic material.

14. The electronic pen according to claim 1, characterized in that the pen tip portion has a tapered shape that becomes thinner as it approaches the tip.

15. The electronic pen according to claim 1, characterized in that the pen tip portion has a diameter larger than the outer diameter of the pen tip side of the housing on the side opposite to the tip in the axial direction, and the pen tip portion is mounted so as to fit over the pen tip side of the housing.

16. The electronic pen according to claim 2, characterized in that the axial recess of the first magnetic material is a through hole, and the side of the through hole opposite to the pen tip side is filled with a member that completely seals the hole.

17. The electronic pen according to claim 4, characterized in that through holes for ventilation and water passage are provided at predetermined positions on the side surface of the outer housing.

18. The electronic pen according to claim 2, characterized in that the elastic member consists of a coil spring provided around the rod-shaped portion between the second magnetic material and the pen tip side of the housing.

19. The electronic pen according to claim 1, characterized in that at least the portion of the waterproof area housing the circuit board is filled with resin.

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