Electronic pen and cartridge for electronic pen

Abstract

Provided is an electronic pen in which fluffing can be reduced even if a core for an electronic pen is configured from fibers bundled in the axial direction, such as a felt. The present invention is provided with: a housing having an opening on the tip side on one end side in the axial direction and having a hollow inside; a pen pressure detection part disposed in the hollow part of the housing; and a core body which has, on one end side in the axial direction, a tip portion that can partially protrude outward from an opening on the tip side of the housing, and which is attached to a pen pressure detection unit disposed in the hollow portion of the housing in a state that the pen pressure applied to the tip portion can be transmitted to the other end side in the axial direction. The front end portion of the core body is composed of fibers bundled in the axial direction, and a contact portion in contact with the input surface of the position detection sensor is formed in a state in which the fibers bundled in the axial direction are exposed. At least a portion of the tip portion facing the inner peripheral wall surface of the opening on the tip side of the housing is covered with a material harder than the fibers bundled in the axial direction.

Description

Technical Field

[0001] The invention relates to an electronic pen and a core body for the electronic pen. Background Art

[0002] The electronic pen is moved by the user on the input surface of the position detection sensor with the tip of the core protruding from the opening on the pen tip side of the housing in contact with the position detection sensor. The movement trajectory of the contact portion of the electronic pen is detected by the position detection sensor as the writing trajectory of the electronic pen.

[0003] The friction between the input surface and the contact part is an important factor in the writing feeling of the electronic pen on the input surface. It is not only related to the surface characteristics of the input surface, but also to the material of the core body in contact with the input surface. Therefore, various materials have been used as the core body of the electronic pen.

[0004] Among the materials of the core of such electronic pens, materials composed of fibers bundled in the axial direction, such as felt, provide a writing feel on the input surface similar to the writing feel when using a pencil on paper. Therefore, there is a great demand for the core of electronic pens composed of felt. However, conventional felt has the problem of being slightly weak in strength.

[0005] Therefore, in the past, various proposals have been made to use felt as the core of the electronic pen, but these proposals are structures that take into account the weak strength of the previous felt. For example, Patent Document 1 (Japanese Patent Publication No. 2014-21674) discloses a core in which a felt is installed at the front end of a hard resin such as POM. In addition, Patent Document 2 (Japanese Patent Publication No. 2016 / 185915) proposes a core in which a felt is installed at the front end of a tube made of a hard member such as metal.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-21674

[0009] Patent Document 2: Japanese Patent Application No. 2016 / 185915 Summary of the invention

[0010] Problems to be solved by the invention

[0011] According to the core bodies of Patent Documents 1 and 2, the felt is attached to the front end of the core body, and the axial center of the core body is made of a hard material. Therefore, a core body that overcomes the weak strength of the felt can be provided.

[0012] However, the felt is composed of fibers bundled and bonded in the axial direction, so there is a problem of so-called fluffing due to friction, etc. That is, the front end of the core body protrudes from the opening of the shell to the outside, but when the electronic pen is brought into contact with the input surface of the position detection sensor in an oblique state, a force in a direction intersecting the axial direction acts on the core body, and sometimes the core body causes axial vibration by the amount of gap between the front end of the core body and the end face of the opening of the shell.

[0013] Therefore, if the front end of the core body is made of fibers bundled in the axial direction such as felt, there is a possibility that the end surface of the opening of the shell and the front end of the core body will rub against each other and cause fluff. If fluff is generated in this way, the front end of the core body will expand, and the area of ​​the contact point with the input surface of the position detection sensor will increase, making it difficult to input the indicated position with high accuracy, and the usability of the electronic pen will deteriorate.

[0014] Furthermore, when the electronic pen includes a writing pressure detection unit for detecting writing pressure applied to the tip of the core body, fuzzing at the tip of the core body will increase friction between the end surface of the opening of the shell and the core body, making it impossible to accurately detect the writing pressure.

[0015] An object of the present invention is to provide an electronic pen that can solve the above problems.

[0016] Means for solving problems

[0017] In order to solve the above-mentioned problem, an electronic pen is provided, characterized in that it comprises:

[0018] The housing has an opening portion having a columnar space with a center line direction in the axial direction and a length in the axial direction of a predetermined length on the pen tip side at one end side in the axial direction, and has a hollow portion in the interior that communicates with the columnar space in the opening portion;

[0019] a pen pressure detection unit, disposed in the hollow portion of the housing; and

[0020] The core body has a front end portion at one end side in the axial direction, which can partially protrude from the opening on the pen tip side of the columnar space in the opening portion of the shell, and the other end side in the axial direction is assembled relative to the writing pressure detection portion arranged in the hollow portion of the shell in a state that the writing pressure applied to the front end portion can be transmitted.

[0021] The front end portion of the core body is composed of fibers bundled in the axial direction, and the contact portion that contacts the input surface of the position detection sensor is formed in a state where the fibers bundled in the axial direction are exposed, and at least a portion of the front end portion that faces the inner circumferential wall of the opening portion on the pen tip side of the shell is covered with a material that is harder than the fibers bundled in the axial direction.

[0022] In the electronic pen of the above structure, the core body has a front end portion which partially protrudes outward from the opening portion on the pen tip side and has a portion facing the inner peripheral wall surface of the opening portion on the pen tip side of the housing. Furthermore, the front end portion is composed of fibers bundled in the axial direction, and the contact portion contacting the input surface of the position detection sensor is formed in a state where the fibers bundled in the axial direction are exposed, and at least the portion of the front end portion facing the inner peripheral wall surface of the opening portion on the pen tip side of the housing is covered with a material harder than the fibers bundled in the axial direction.

[0023] Through this structure, the fiber felt bundled in the axial direction is exposed at the contact portion of the front end of the core body with the input surface of the position detection sensor, thereby providing an electronic pen that can provide a writing feel achieved by the fiber felt bundled in the axial direction and can prevent friction between the fibers bundled in the axial direction at the front end of the core body and the inner circumferential wall surface of the opening portion on the pen tip side of the shell, thereby reducing the generation of fuzz at the front end of the core body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a diagram for explaining a configuration example of an embodiment of the electronic pen according to the present invention.

[0025] Figure 2 It is a diagram for explaining a configuration example of an embodiment of a core body for a digital pen according to the present invention.

[0026] Figure 3 It is a diagram for explaining a configuration example of another embodiment of the electronic pen core body of the present invention.

[0027] Figure 4 It is a diagram for explaining a configuration example of a first other embodiment of the electronic pen of the present invention.

[0028] Figure 5 It is a diagram for explaining another configuration example of the first other embodiment of the electronic pen according to the present invention.

[0029] Figure 6 It is a diagram showing a comparative example for explaining a configuration example of a second other embodiment of the electronic pen of the present invention.

[0030] Figure 7 It is a diagram for explaining a configuration example of a second other embodiment of the electronic pen of the present invention.

[0031] Figure 8 It is a diagram for explaining a configuration example of a digital pen core body used in a second other embodiment of the digital pen according to the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, the embodiment of the electronic pen of the present invention will be described together with the embodiment of the electronic pen core. Figure 1 Side description.

[0033] [Embodiment of the electronic pen]

[0034] Figure 1 The following is a structural example of an electronic pen 1 according to this embodiment, which is an electromagnetic induction type electronic pen. The electronic pen 1 according to this embodiment has a cylindrical (in this example, a cylindrical) housing 2. One end side in the axial direction of the housing 2 is a gradually tapering pen tip side, and an opening 21 is provided, and the other end side in the axial direction opposite to the pen tip side (referred to as the rear end side) is closed.

[0035] like Figure 1 As shown, the opening 21 on the pen tip side of the housing 2 has a columnar space (in this example, a cylindrical space with a circular cross section having a uniform diameter R1) with the axial direction as the center line direction and the axial length being a predetermined length L. In the cylindrical space, the inner peripheral wall surface 21a of the opening 21 is exposed, and the cylindrical space is connected to the external space through the opening on the pen tip side.

[0036] In the internal hollow portion 2a of the shell 2 of the electronic pen 1 that is connected to the cylindrical space of the opening portion 21, a printed circuit board 6 that houses electronic components such as a coil 3 for position detection, a pen pressure detection portion 4, and a capacitor 5 that forms a resonant circuit together with the coil 3 is arranged in sequence from the pen tip side in the axial direction of the shell 2.

[0037] The coil 3 is wound around a ferrite core 7, which is an example of a magnetic core. The ferrite core 7 around which the coil 3 is wound is housed near the opening 21 on the pen tip side of the housing 2. Figure 1 As shown, in this example, a buffer member 71 is disposed at the front end of the ferrite core 7 on the pen tip side.

[0038] The ferrite core 7 is provided with a through hole 7a in the axial direction. The centerline position of the through hole 7a of the ferrite core 7 is configured to coincide with the centerline position of the opening 21 of the housing 2. The diameter R2 of the through hole 7a of the ferrite core 7 is smaller than the diameter R1 of the opening of the opening 21 of the housing 2. Figure 1 In the figure, for the convenience of explanation, the housing 2, the coil 3 and the ferrite core 7 are shown in cross-section.

[0039] The pressure detector 4 provided at the rear end of the ferrite core 7 in the hollow portion 2a of the housing 2 includes a fitting portion 9 into which the axial portion 8S of the core 8 described later fits. The fitting portion 9 of the pressure detector 4 is formed as an extension of the through hole 7a of the ferrite core 7.

[0040] In this example, the pen pressure detection unit 4 is a variable capacitance capacitor structure that detects the pressure (pen pressure) applied to the front end of the core 8 as a change in electrostatic capacitance. This pen pressure detection unit can use a structure in which the contact area between the dielectric and the conductive elastic member changes according to the applied pressure, thereby changing the electrostatic capacitance (for example, see patent document: Japanese Patent Publication No. 2016-126503), a pen pressure detection unit composed of a semiconductor device in which the distance between two electrodes facing each other through an air layer as a dielectric changes according to the applied pressure (for example, see patent document: Japanese Patent Publication No. 2013-161307), and the like, and its detailed description is omitted here.

[0041] In the electronic pen 1 of this embodiment, the core 8 of the embodiment having the structure described below is configured such that the core 8 is inserted into the housing 2 through the cylindrical space of the opening 21, penetrates the through hole 7a of the ferrite core 7, and is fitted into the fitting portion 9 provided in the writing pressure detection portion 4 to be held thereby. When the core 8 is fitted into the fitting portion 9 and assembled into the electronic pen 1, as shown in FIG. Figure 1 As shown, a portion of one end side (pen tip side) of the core body 8 in the axial direction is in a state of protruding to the outside from the opening on the pen tip side of the columnar space of the opening portion 21 of the housing 2 .

[0042] [Embodiment of the core]

[0043] Figure 2 1 is a diagram for explaining a core body 8 of this embodiment. Figure 2 (A) shows the core 8 removed from the electronic pen 1, Figure 2 (B) is a longitudinal sectional view of the core 8. In this example, the core 8 is a rod-shaped member having a circular cross section. Figure 1 and Figure 2 As shown, it has a structure in which a front end portion 8T on one end side in the axial direction and a shaft portion 8S extending from the front end portion 8T to the other end side in the axial direction are integrally connected.

[0044] In the core 8 of this embodiment, as Figure 2 As shown in (B), the axial portion 8S and the front end portion 8T are formed as an integral body by a felt 81 which is an example of a material composed of fibers bundled in the axial direction. The felt 81 is formed by bundling and bonding fibers in the axial direction. In this embodiment, the felt 81 particularly uses a felt in which the strength of the fiber bundle is increased by compressing and fixing the felt raw material in the axial direction, thereby making it possible to form the core body 8 having the front end portion 8T and the axial portion 8S as a molded product based on the felt 81.

[0045] In the core 8 of this embodiment, as Figure 2As shown in FIG. 8B , the axial core portion 8S made of the felt 81 is formed in a rod shape having a circular cross section and a diameter R3 that is smaller than the diameter R2 of the through hole 7 a of the ferrite core 7 .

[0046] In this example, the tip portion 8T formed integrally with the shaft portion 8S by the felt 81 is formed to have a diameter R4 greater than the diameter R3 of the shaft portion 8S (R4>R3). Figure 1 and Figure 2 As shown, the front end of the front end portion 8T side of the felt 81 is configured to have a convex curved surface such as a cannonball shape.

[0047] Furthermore, in the core body 8 of this embodiment, the entire portion of the diameter R4 of the front end portion 8T, except for the convex surface portion of the front end of the felt 81, is covered by a hard coating portion 82 made of a material harder than the felt 81, such as a hard resin. In this example, the hard coating portion 82 is made of POM (Polyoxymethylene) as an example of a hard resin, and is configured to cover the felt 81 with a uniform thickness. It should be noted that the hard material constituting the hard coating portion 82 is not limited to a hard resin, and may be, for example, a metal.

[0048] In this case, the convex surface portion of the front end of the front end portion 8T is not covered by the hard coating portion 82, so the felt 81 is exposed. The convex surface portion of the felt 81 exposed becomes a contact portion 8Tc that contacts the input surface of the position detection sensor in the front end portion 8T of the core 8. The length d in the axial direction of the convex surface contact portion 8Tc not covered by the hard coating portion 82 (see Figure 2 (A) and (B)) are lengths sufficient as protrusion amounts when the tip of the core 8 of the electronic pen 1 is brought into contact with the input surface of the position detection sensor to perform writing.

[0049] As described above, in the front end portion 8T of the core 8, the felt 81 is covered by the hard covering portion 82 except for the contact portion 8Tc, so the diameter R5 of the portion except for the contact portion 8Tc is the diameter R4 of the felt at the front end portion 8T plus the thickness of the hard covering portion 82. Figure 1 As shown, the maximum diameter R5 of the tip portion 8T is selected to be slightly smaller than the diameter R1 of the opening 21 of the housing 2 of the electronic pen 1. That is, it is selected in the order of R1>R5>R4>R3.

[0050] Furthermore, in this embodiment, the contact portion 8Tc side of the hard coating portion 82 is formed as a tapered portion 82t whose outer diameter gradually decreases from R5 to the diameter R4, so that no step is generated at the boundary between the contact portion 8Tc and the hard coating portion 82. Therefore, in the electronic pen 1 of this embodiment, when the contact portion 8Tc of the core 8 is brought into contact with the input surface of the position detection sensor to perform writing input, there is almost no step at the boundary between the contact portion 8Tc and the hard coating portion 82. This has the effect of being able to effectively use the entire length d of the contact portion 8Tc as a contact portion with the input surface.

[0051] That is, when the angle between the axial direction of the electronic pen 1 and the input surface of the position detection sensor is not a right angle, that is, when the electronic pen 1 is used at an inclination relative to the input surface of the position detection sensor, if there is a step at the boundary between the contact portion 8Tc and the hard coating portion 82, the felt 81 and the input surface will not be in contact at a portion of the contact portion 8Tc corresponding to the size of the step. In contrast, in the core 8 of this embodiment, since there is almost no step at the boundary between the contact portion 8Tc and the hard coating portion 82, the entire contact portion 8Tc of the length d can be effectively used as a contact portion.

[0052] The core 8 constructed as described above is inserted into the housing 2 from the side of the axial portion 8S through the opening 21 of the housing 2 of the electronic pen 1, and the axial portion 8S penetrates the through hole 7a of the ferrite core 7. The end of the axial portion 8S of the core 8 is fitted into the fitting portion 9 provided in the writing pressure detection unit 4, and the core 8 is assembled to the electronic pen 1. The assembled core 8 can be pulled out by holding the portion protruding from the opening 21 of the housing 2. That is, in the electronic pen 1 of this embodiment, the core 8 can be attached and detached and can be replaced.

[0053] In the electronic pen 1 of this embodiment, the length of the core 8 in the axial direction and the length of the ferrite core 7 in the axial direction are selected so that when the end of the axial portion 8S is fitted into the fitting portion 9 and the core 8 is assembled into the electronic pen 1, Figure 1 As shown, the front end portion 8T of the core 8 is in a state where the contact portion 8Tc and a portion of the hard coating portion 82 protrude to the outside from the opening portion 21 of the shell 2 and the remaining portion of the hard coating portion 82 is opposite to the inner peripheral wall surface 21a of the opening portion 21 of the shell 2 exposed to the cylindrical space.

[0054] That is, in the electronic pen 1 of this embodiment, if Figure 1As shown, the front end portion 8T of the core body 8 is partially protruded from the opening 21 of the housing 2 to the outside to become the pen tip, and the remaining portion is opposed to the inner peripheral wall surface 21a of the opening 21 of the housing 2 that is exposed to the cylindrical space, and friction may occur in the portion opposed to the inner peripheral wall surface 21a. In particular, when the user holds the electronic pen 1 and performs a position indication operation on the input surface of the position detection sensor, for example, the inner peripheral wall surface 21a of the opening 21 of the housing 2 and the outer peripheral surface of the front end portion 8T of the core body 8 may come into contact with each other and cause friction.

[0055] However, in this embodiment, in the front end portion 8T of the core body 8, the hard coating portion 82 is not the felt 81 but the hard coating portion 82 facing the inner peripheral wall surface 21a of the opening portion 21 of the housing 2. Therefore, the contact portion with the inner peripheral wall surface 21a of the opening portion 21 of the housing 2 is the portion of the hard coating portion 82, and the inner peripheral wall surface 21a of the opening portion 21 of the housing 2 and the felt 81 are prevented from rubbing against each other, so that the felt 81 in this portion can be prevented from being fuzzed.

[0056] As mentioned above, the maximum outer diameter R5 of the front end portion 8T of the core body 8 is smaller than the diameter R1 of the opening of the opening portion 21 of the shell 2 of the electronic pen 1, and a gap is formed between the outer peripheral surface of the hard coating portion 82 of the front end portion 8T of the core body 8 and the inner peripheral wall surface 21a of the opening portion 21 of the shell 2 of the electronic pen 1. However, in this embodiment, in the front end portion 8T of the core body 8, it is the hard coating portion 82 rather than the felt 81 that is opposite to the inner peripheral wall surface 21a, so there is no need to consider the generation of fuzzing of the felt 81, and the gap can be selected in a manner that is as small as possible.

[0057] Furthermore, when the user of the electronic pen 1 applies writing pressure by placing the contact portion 8Tc of the core 8 against the input surface of the position detection sensor, the core 8 moves in the axial direction according to the magnitude of the applied writing pressure, and transmits the writing pressure to the writing pressure detection unit 4. When writing pressure is applied to the front end of the core 8, the inner peripheral wall surface 21a of the opening 21 of the housing 2 and the outer peripheral surface of the front end 8T of the core 8 may come into contact. However, in the electronic pen 1 of this embodiment, the contact portion is a portion of the hard coating portion 82 of the front end 8T of the core 8. Therefore, even when the core 8 moves in the axial direction, the inner peripheral wall surface 21a of the opening 21 of the housing 2 and the felt 81 can be prevented from rubbing against each other, and the felt 81 in this portion can be prevented from fuzzing.

[0058] Furthermore, when the felt 81 is not covered by the hard coating 82 and fluffs up, the friction between the fluffed portion and the inner peripheral wall surface 21a of the opening 21 may affect the writing pressure value detected by the writing pressure detection unit 4. In contrast, in this embodiment, the felt 81 is covered by the hard coating 82 at the front end 8T of the core 8, so the fluffing of the felt 81 does not occur, and the writing pressure detection unit 4 can accurately detect the writing pressure applied to the front end of the core 8.

[0059] like Figure 1 As shown, in the electronic pen 1 of this embodiment, not only the tip 8T of the core 8 but also a portion of the axis 8S including the boundary with the tip 8T is in a state of facing the inner peripheral wall 21a of the opening 21 of the housing 2. However, in this embodiment, the axis 8S of the core 8 is smaller than the diameter R5 of the tip 8T, so the gap between the inner peripheral wall 21a of the opening 21 of the housing 2 and the facing portion of the axis 8S is relatively large. In particular, in this embodiment, the diameter R4 of the tip 8T is selected to be larger than the diameter R3 of the axis 8S, so the gap between the inner peripheral wall 21a of the opening 21 of the housing 2 and the facing portion of the axis 8S is larger. Therefore, the portion of the felt 81 of the axis 8S hardly rubs against the inner peripheral wall 21a of the opening 21 of the housing 2.

[0060] [Effects of Embodiment]

[0061] As described above, in the electronic pen 1 using the core 8 of this embodiment, even if the gap between the front end of the core and the inner circumferential wall of the opening of the shell is designed to be small, since the felt 81 of the front end 8T of the core 8 is covered by the hard covering portion 82, no friction will be generated between the felt 81 and the inner circumferential wall of the opening 21 of the shell 2, and fuzzing will not occur in this part.

[0062] Furthermore, in this embodiment, since the tip 8T of the core 8 includes the contact portion 8Tc not covered by the hard coating 82, the contact portion 8Tc can be used to input the indicated position on the input surface of the position detection sensor with high accuracy, and the electronic pen is easy to use.

[0063] Furthermore, in this embodiment, since the friction between the inner peripheral wall surface 21a of the opening portion 21 of the shell 2 of the electronic pen 1 and the felt 81 of the core body 8 is prevented by the hard covering portion 82, the following effect is achieved: even if the felt 81 is used as the raw material of the core body 8, the influence of the fuzzing of the felt can be suppressed in the pen pressure detection unit 4 and accurate pen pressure detection can be performed.

[0064] Furthermore, the electronic pen 1 according to this embodiment also has the following effect: the value of the so-called ON load for starting the detection of the pen pressure value by detecting the contact between the contact portion 8Tc of the core body 8 and the input surface of the position detection sensor using the pen pressure detection unit 4 can be reduced compared to the case where the felt 81 is completely exposed at the front end portion 8T.

[0065] In addition, in this embodiment, since the felt 81 is made of a felt whose strength is enhanced by compressing the felt raw material in the axial direction, and the front end portion 8T and the axial portion 8S are constructed as an integral part of the felt 81, the following effects are achieved: the core body 8 is simple in structure and easy to manufacture, and the manufacturing cost can also be reduced compared with the cases of the aforementioned patent documents 1 and patent document 2.

[0066] [Other embodiments or modifications of the core]

[0067] In the core body 8 of the above-mentioned embodiment, the felt 81 has different diameters at the front end portion 8T and the axial center portion 8S. Figure 3 The core 8A of the example shown in (A) is a felt 81A having the same diameter at the front end 8AT and the axial center 8AS. In the core 8A of this example, the front end 8AT of the felt 81A is also configured to be covered by the hard coating 82A except for the contact portion 8ATc. In this example, the contact portion 8ATc side of the hard coating 82A is also a tapered portion 82At.

[0068] In the core body 8 of the above-mentioned embodiment, the felt 81 of the axial core portion 8S is exposed. Figure 3 The core 8B of the example shown in (B) is configured such that the axial core 8BS is also covered by the hard coating 83. In the core 8B of this example, the front end 8BT of the felt 81B is configured to be covered by the hard coating 82B except for the contact portion 8BTc, similarly to the core 8 of the above-mentioned embodiment. In addition, the contact portion 8BTc side of the hard coating 82B is also a tapered portion 82Bt in this example.

[0069] Should Figure 3 The hard coating 83 covering the axial core 8BS in the core 8B of the example (B) may be made of the same hard material as the hard coating 82B covering the front end 8BT, or may be made of another type of hard material. Figure 3 In the core body 8B of the example (B) as well, the maximum diameter of the front end portion 8BT is larger than the diameter of the axial core portion 8BS covered by the hard coating portion 83 .

[0070] According to the core body 8B of this example, since the axial portion 8BS is also covered with the hard coating portion 83, the felt 81B of the axial portion 8BS can also be prevented from being fuzzed.

[0071] In the core body 8 of the above-described embodiment, both the tip portion 8T and the axial core portion 8S are formed as a molded product of the felt 81. Figure 3 As in the core 8C of the example (C), the axial center portion is formed as a member independent of the core portion.

[0072] That is, in Figure 3 In the core body 8C of the example (C), the axial core portion 8CS is composed of a tube 84 made of a hard material, such as metal, and has a structure in which the front end portion 8CT is mounted on the tube 84. The front end portion 8CT of this example is similar to the core body 8 of the above-mentioned example, and is covered with a hard coating portion 82C except for a contact portion 8CTc at the front end of a felt 81C of a shell shape, for example. In this example, the contact portion 8CTc side of the hard coating portion 82C is also a tapered portion 82Ct.

[0073] like Figure 3 As shown in (C), the felt 81C constituting the front end portion 8CT of this example includes a fitting portion 81Ca for inserting into the hollow portion 84a of the tube 84 to fit and fix the front end portion 8CT to the tube 84. In this case, the fitting portion 81Ca fitted and inserted into the hollow portion 84a of the tube 84 can also be fixed more firmly by bonding with an adhesive.

[0074] It should be noted that, in this example, the rear end side of the hollow portion 84a of the tube 84 of the axial portion 8CS is sealed by fitting a predetermined member 85. The predetermined member 85 may be felt or other raw materials. In addition, the rear end side of the hollow portion 84a of the tube 84 of the axial portion 8CS may not be sealed but may remain open.

[0075] In the core body 8C of this example, since the axial core portion 8CS is not formed of felt, the strength of the core body can be further improved.

[0076] [Other Embodiments of the Electronic Pen]

[0077] <First other embodiment>

[0078] In recent years, electronic pens have been becoming refill-type in order to diversify the overall shape (outer shell) (design emphasis). To achieve this, an electronic pen has been proposed in which the electronic pen main body, which has the position indication function relative to the position detection sensor and the pen pressure detection function, which are the main functions of the electronic pen, is made into a refill. This electronic pen can be constructed simply by accommodating and inserting the electronic pen main body, which is formed into a refill structure, into the hollow part of the cylindrical outer shell. Therefore, the degree of freedom in the design of the shell of the electronic pen is increased, and the diversification of electronic pens becomes easy. In addition, like the refill of a ballpoint pen, the replacement of the electronic pen main body becomes easy and very convenient. In addition, a push-type electronic pen can be constructed in which the refill-type electronic pen main body is pushed out and in, like a push-type ballpoint pen.

[0079] Figure 4 This is a diagram showing a configuration example of an electronic pen 1A according to a first alternative embodiment of the present invention, in which the electronic pen main body is configured to be accommodated in the housing 2A as an electronic pen refill 30. In this embodiment, the electronic pen refill 30 is attachable to and detachable from the housing 2A. This example is a case of an electromagnetic induction type electronic pen.

[0080] like Figure 4 As shown in (A) and (B), the electronic pen 1A of this embodiment has a push-type structure in which an electronic pen refill 30 is housed in a hollow portion 2Aa of a cylindrical shell 2A (hereinafter referred to as the pen shell 2A in the description of this embodiment) and the pen tip side of the electronic pen refill 30 is inserted and removed from an opening 21A on one end side of the pen shell 2A in the axial direction by pressing a cam mechanism portion 40.

[0081] Figure 4 (A) shows a state where the entire electronic pen refill 30 is accommodated in the hollow portion 2Aa of the pen case 2A. Figure 4 (B) shows a state where the pen tip side of the electronic pen refill 30 protrudes from the opening 21A of the pen case 2A by pressing the cam mechanism 40. Figure 4 In the example of FIG. 1 , pen case 2A as electronic pen 1A is made of a transparent synthetic resin and its interior is see-through.

[0082] like Figure 4As shown, the pen housing 2A and the push cam mechanism 40 provided in the pen housing 2A are composed of a cam body 41, a push rod 42 and a rotating member 43, and have the same function as the outer housing and push cam of a well-known commercially available push-type ballpoint pen. The cam body 41 is formed on the inner wall surface of the cylindrical pen housing 2A. The push rod 42 protrudes from the opening 2Ab on the side opposite to the pen tip side of the pen housing 2A in a manner that can receive the user's push operation. The rotating member 43 has a fitting portion 43a for fitting the end of the electronic pen refill 30 on the side opposite to the pen tip side in a detachable manner.

[0083] exist Figure 4 In the state (A), if the end 42a of the push rod 42 is pressed, the electronic pen refill 30 is locked in the pen case 2A by the push cam mechanism 40. Figure 4 In the state (B), the pen tip side of the electronic pen refill 30 is in a state of protruding from the opening 21A of the pen case 2A. Figure 4 When the end 42a of the push rod 42 is pressed again, the locking state is released by the push cam mechanism 40, and the position of the electronic pen refill 30 in the pen housing 2A is restored to Figure 4 The detailed structure and operation of the push cam mechanism 40 are well known, and therefore, the description thereof will be omitted here.

[0084] <Structural Example of Electronic Pen Refill 30>

[0085] Figure 4 (C) is a diagram showing a structural example of the electronic pen refill 30 in this embodiment. Figure 4 As shown in (C) of FIG. 1 , the electronic pen refill 30 of this example includes a signal transmitting member 31 and a refill case portion 32 that holds a writing pressure detecting portion and houses a printed circuit board on which an electronic circuit is arranged.

[0086] The signal transmission member 31 is composed of a coil 311 constituting a resonant circuit for transmitting and receiving signals with a position detection sensor by electromagnetic induction, and a magnetic core (a ferrite core 312 in this example) wound with the coil 311. A through hole 312a is formed in the axial direction at the center position of the ferrite core 312.

[0087] The lead case 32 is made of resin material, for example, and fits with the ferrite core 312 of the signal transmitting member 31, and holds the writing pressure detection unit 4A and a printed circuit board (not shown). A capacitor forming a resonance circuit with the coil 311 is arranged on the printed circuit board.

[0088] And, in this example, using Figure 1 and Figure 2The core body 8 of the embodiment described above is inserted through the through hole 312a of the ferrite core 312, fitted into the fitting portion 9A of the writing pressure detection unit 4A, and detachably mounted to the electronic pen refill 30. Thus, the pressure (writing pressure) applied to the contact portion 8Tc at the front end of the pen tip side of the core body 8 is applied to the writing pressure detection unit 4A.

[0089] In this example, the pen pressure detection unit 4A uses a pen pressure detection unit that uses a semiconductor chip composed of MEMS (Micro Electro Mechanical Systems) elements as a variable capacitance capacitor (for example, refer to the patent document (Japanese Patent Application Publication No. 2013-161307)). It should be noted that, similar to the pen pressure detection unit 4, the pen pressure detection unit 4A may also use a structure in which the contact area between the dielectric and the conductive elastic member changes according to the applied pressure, thereby changing the electrostatic capacitance (for example, refer to the patent document: Japanese Patent Application Publication No. 2016-126503).

[0090] In this embodiment, as described above, the electronic pen refill 30 is formed into a refill structure having the same outer shape as a ballpoint pen refill by coupling the signal transmitting member 31 and the refill case 32 in the axial direction.

[0091] Furthermore, in the electronic pen 1A of this embodiment, the length of the core body 8 in the axial direction, the length of the ferrite core 312 in the axial direction, and the size of the pressing stroke of the pressing cam mechanism 40 are selected so that: when the pressing rod 42 is pressed by the user and the pen tip side of the electronic pen refill 30 protrudes from the opening 21A of the pen case 2A by the pressing cam mechanism 40, as shown in FIG. Figure 4 As shown in (B), the front end portion 8T of the core body 8 is in a state where the contact portion 8Tc and a portion of the hard covering portion 82 protrude outward from the opening portion 21A of the pen housing 2A and the remaining portion of the hard covering portion 82 is opposite to the inner circumferential wall surface 21Aa of the opening portion 21A of the housing 2A that forms a cylindrical space.

[0092] Therefore, in Figure 4 When the electronic pen 1A is in a state where a portion of the front end portion 8T of the core body 8 shown in (B) protrudes outward and is performing writing input on the input surface of the position detection sensor, as in the above-mentioned embodiment, since the felt 81 at the front end portion 8T of the core body 8 is covered by the hard covering portion 82, no friction is generated between the felt 81 and the inner circumferential wall surface of the opening portion 21 of the shell 2, thereby preventing the felt 81 from fuzzing.

[0093] And, in this Figure 4In the electronic pen 1A of the embodiment, when the electronic pen refill 30 is moved in the axial direction by pressing to make the front end 8T of the core body 8 arranged on the electronic pen refill 30 appear and disappear, since the felt 81 of the front end 8T is covered by the hard covering portion 82, no friction is generated between the felt 81 and the inner peripheral wall surface of the opening portion 21 of the shell 2, which can prevent the felt 81 from fuzzing.

[0094] It should be noted that the core body mounted on the electronic pen refill 30 is not limited to the core body 8 in the above example, and may be any other core body. Figure 3 The cores 8A, 8B, and 8C of other examples and the cores of other modified examples are shown.

[0095] In addition, Figure 4 In the example of FIG. 1 , core body 8 is configured to be attachable to and detachable from digital pen refill 30 . However, the core body may be configured to be fixedly attached to the digital pen refill.

[0096] Figure 5 It is a diagram for explaining an example of an electronic pen refill 30D in which a core body is fixedly mounted. It should be noted that, although not shown in the figure, the electronic pen refill 30D of this example can be stored in the pen case 2A instead of the electronic pen refill 30 of the above example and used as the electronic pen 1A.

[0097] like Figure 5 (A) and Figure 5 As shown in (B), in this example, the signal transmitting member 31D is composed of a coil 311 and a ferrite core 312D. In this example, the ferrite core 312D does not have a through hole in the axial direction, but instead has a fitting recess 312Da on the pen tip side.

[0098] In this example, the core 8D does not have an axial center portion, and is formed into a structure with only the front end portion 8DT. In addition, the front end portion 8DT of the core 8D has a fitting protrusion 8DTa that fits into the fitting recess 312Da of the ferrite core 312D on the rear end side of the felt 81D. The fitting protrusion 8DTa protruding toward the rear end side of the front end portion 8DT is fitted into the fitting recess 312Da of the ferrite core 312D, and the two are bonded, for example, so that the front end portion 8BT of the core 8D is fixedly mounted on the pen tip side of the ferrite core 312D.

[0099] In this example, similarly to the above-described embodiment, the front end portion 8DT of the core body 8D has a contact portion 8DTc where the felt 81D is exposed and includes a portion covered by the hard coating portion 82D.

[0100] Furthermore, the structure is such that when the push rod 42 is pushed in by the user and the cam mechanism 40 is pushed, the pen tip side of the electronic pen refill 30D protrudes from the opening 21A of the pen case 2A. Figure 4 Similarly to the situation shown in (B), the front end portion 8DT of the core body 8D becomes a contact portion 8DTc and a part of the hard covering portion 82D protrudes outward from the opening portion 21A of the pen housing 2A and the remaining part of the hard covering portion 82D is opposite to the inner circumferential wall surface 21Aa of the opening portion 21A of the housing 2A exposed to the cylindrical space.

[0101] In addition, in the electronic pen refill 30D of this example, since the core body 8D is fixed to the ferrite core 312D, the following configuration is used to detect the writing pressure applied to the contact portion 8DTc of the core body 8D.

[0102] In this example, the refill housing 32 is composed of a first tubular body 321 in which electronic circuit components are arranged and a second tubular body 322 in which components for detecting writing pressure are arranged. Figure 5 As shown in (B), a printed circuit board 33 is arranged in the first cylindrical body 321, and a circuit component 34 including a capacitor that forms a resonant circuit together with the coil 311 is arranged on the printed circuit board 33. Figure 4 As shown in (B), the winding start end 311a and the winding end end 311b of the coil 311 are electrically connected to one end and the other end of the capacitor.

[0103] In this example, the second cylindrical body 322 is divided into a long portion 322a and a short portion 322b, and a pen pressure detection portion 36 is provided near the joint portion 35. Figure 5 As shown in (B), in this example, the long-dimension portion 322a and the short-dimension portion 322b are connected at the connection portion 25 via the connecting rod member 351 and the coil spring 352. In this case, the long-dimension portion 322a and the short-dimension portion 322b are configured so that they are always elastically displaced in the axial direction in a manner away from each other by the coil spring 352, but are locked at a predetermined position by the connecting rod member 351 and do not further displace in the axial direction.

[0104] And, if Figure 5 As shown in FIG. 2(B) , in this embodiment, the writing pressure detection unit 36 ​​is provided in the long portion 322 a . Also, the one end 351 a side of the connecting rod member 351 is configured to function as a pressing portion of the writing pressure detection unit 36 ​​.

[0105] The pen pressure detection unit 36 ​​of this example is also similar to the above-mentioned pen pressure detection unit, and is formed as a variable capacitance capacitor whose static capacitance changes according to the pen pressure, using a pen pressure detection unit of a well-known structure described in, for example, Japanese Patent Laid-Open No. 2011-186803 and Japanese Patent Laid-Open No. 2013-161307. In this embodiment, the variable capacitance capacitor is connected in parallel with the resonance circuit composed of the coil 311 and the above-mentioned capacitor.

[0106] When pressure is applied to the contact portion 8DTc of the core body 8D while the electronic pen refill 30D is stored in the pen case of the electronic pen, a force is applied to the entire long portion 322a side of the electronic pen refill 30D to move toward the short portion 322b side against the elastic force of the coil spring 352, and the static capacitance of the writing pressure detection unit 36 ​​becomes a static capacitance corresponding to the writing pressure. Therefore, the resonant frequency of the resonance circuit changes due to the static capacitance corresponding to the writing pressure applied to the contact portion 8DTc of the core body 8D detected by the writing pressure detection unit 36, and the writing pressure value is sent to the position detection sensor side as the change in the resonant frequency.

[0107] When the electronic pen refill 30D of this example is used, the same as that obtained when the aforementioned Figure 4 The electronic pen refill 30 of the example has the same operational effects as the electronic pen 1A.

[0108] <Second other embodiment>

[0109] Since the electronic pen is composed of a combination of fine parts, if the tolerances of each part are accumulated, the amount of protrusion of the front end of the core from the opening of the shell will change. In addition, the amount of protrusion of the front end of the core from the opening of the shell may also change due to not only the tolerances of the parts but also the use of the electronic pen.

[0110] In this way, when the amount of protrusion of the front end portion 8T of the core body 8 from the front end opening of the cylindrical space of the opening portion 21 of the housing 2 of the electronic pen 1 becomes larger due to the tolerance of the components, Figure 6 When the position of the joint between the front end portion 8T of the core body 8 and the axial portion 8S is close to the opening side of the front end side of the cylindrical space of the opening portion 21 of the shell 2 of the electronic pen 1 as shown by the dotted line, when the user tilts the electronic pen 1 obliquely relative to the input surface and applies pen pressure, the core body 8 may bend near the boundary between the front end portion 8T and the axial portion 8S.

[0111] The electronic pen according to the second alternative embodiment is an example that can solve this problem, and has a characteristic structure on the pen tip side of the casing. Figure 7 1E is a diagram showing the pen tip side of the electronic pen 1E according to the second alternative embodiment. Figure 1The same parts of the electronic pen 1 described above are marked with the same reference numerals. Figure 8 It is a cross-sectional view for explaining a configuration example of a core body 8E used in a digital pen 1E according to the second alternative embodiment.

[0112] In the digital pen 1E of this embodiment, the structure of the pen tip side of the case 2E is different from the case 2 of the digital pen 1 of the above-mentioned embodiment.

[0113] On the pen tip side of the housing 2 of the electronic pen 1 in the above-mentioned embodiment, as shown in FIG. Figure 6 As shown, a tapered portion 2TPa is formed whose thickness gradually decreases toward the opening of the opening portion 21, and the front end side of the tapered portion 2TPa becomes a flat annular end face 2R in a direction perpendicular to the axial direction. That is, the inner peripheral edge (in this example, a circular edge) 21ae of the opening of the pen tip side of the opening portion 21 of the housing 2, which is exposed to the cylindrical space, becomes the inner peripheral edge of the flat annular end face 2R in a direction perpendicular to the axial direction at the front end of the pen tip side of the housing 2.

[0114] In contrast, Figure 7 As shown, a tapered portion 2TPb is formed at the front end of the pen tip side of the housing 2E of the electronic pen 1E of this embodiment, wherein the thickness gradually decreases (in this example, the diameter gradually decreases) toward the inner peripheral wall surface 21Ea of the opening 21E exposed to the cylindrical space, and the inner peripheral edge 21Eae of the opening on the pen tip side of the opening 21E. That is, at the front end of the pen tip side of the housing 2E of the electronic pen 1E of this embodiment, no tapered portion 2TPb is formed. Figure 6 Instead of the annular end face 2R which is a plane in a direction perpendicular to the axial direction, a taper 2TPb (second taper) is formed on the pen tip side along the inner peripheral edge 21ae of the opening on the pen tip side facing the opening 21E, following the taper 2TPa (first taper).

[0115] Therefore, if Figure 7 As shown, the length of the cylindrical space of the opening 21E on the pen tip side of the housing 2E of the electronic pen 1E of this embodiment in the axial direction is greater than Figure 1 The length L of the electronic pen 1 in the example is longer than the LE of the portion of the tapered portion 2TPb. In this case, in this example, Figure 7 As shown, the inclination angle of the tapered portion 2TPb (second tapered portion) with respect to the axial direction is formed to be larger than the inclination angle of the tapered portion 2TPa (first tapered portion) with respect to the axial direction.

[0116] It should be noted that it is not necessary that the inclination angle of the cone 2TPb relative to the axial direction is greater than the inclination angle of the cone 2TPa relative to the axial direction. The inclination angle of the cone 2TPb relative to the axial direction may be smaller than the inclination angle of the cone 2TPa relative to the axial direction, or the inclination angle of the cone 2TPa relative to the axial direction may be equal to the inclination angle of the cone 2TPb relative to the axial direction. Figure 7 In the example, the taper 2TPb is formed in a manner that does not generate steps from the taper 2TPa but is smoothly continuous, but the taper 2TPa and the taper 2TPb may also be formed in a state where steps are generated or they are continuous in an uneven state.

[0117] Furthermore, the core 8E used in the electronic pen 1E of this embodiment is as follows: Figure 8 That is, the core body 8E of this example is constituted as follows: for a cylindrical rod-shaped member of felt 81E having a diameter slightly smaller than the diameter R3 of the axial core portion 8ES, the entirety of the felt 81E of the rod-shaped member except for the contact portion 8ETc of the cannonball-shaped curved convex portion on the pen tip side is covered with a hard covering portion 82E.

[0118] In this case, in the front end portion 8ET of the core body 8E, there is a portion where the felt 81E is covered by the hard coating 82E in a manner that the maximum diameter becomes R5 except for the contact portion 8ETc, and a tapered portion 82Et extending from the pen tip side of the portion of the hard coating 82E with a diameter of R5 to the contact portion 8ETc, and in this example, there is also a tapered portion 82Ee whose diameter gradually decreases from the side of the portion of the hard coating 82E with a diameter of R5 opposite to the pen tip side toward the axial portion 8ES. The length of the front end portion 8ET of the core body 8E in this example in the axial direction is greater than that of the tapered portion 82Ee whose diameter gradually decreases from the side of the portion of the hard coating 82E with a diameter of R5 opposite to the pen tip side toward the axial portion 8ES. Figure 1 The front end portion 8T of the core body 8 in this example is long.

[0119] As described above, the electronic pen 1E according to this embodiment has a tapered portion 2TPa formed on the pen tip side of the housing 2E, which is formed by the inner peripheral edge 21ae of the opening toward the pen tip side of the opening 21E. The length LE of the cylindrical space of the opening 21E in the axial direction is smaller than Figure 1 In the example of the electronic pen 1 , the length L in the axial direction of the cylindrical space of the opening 21 of the housing 2 is long.

[0120] Therefore, even if the protrusion of the front end portion 8T of the core body 8 from the opening at the front end of the cylindrical space of the opening portion 21 of the shell 2 of the electronic pen 1 increases due to component tolerances, etc., it is possible to prevent the boundary between the front end portion 8ET of the core body 8E and the axial portion 8ES from approaching the opening side of the front end side of the cylindrical space of the opening portion 21 of the shell 2 of the electronic pen 1, and the problem of the core body 8E bending near the boundary between the front end portion 8ET and the axial portion 8ES can be improved.

[0121] Furthermore, in the core 8E of this embodiment, the boundary between the front end portion 8ET and the axial portion 8ES is not a step portion formed by a vertical wall, but has a tapered portion 82Ee whose diameter gradually decreases from the side opposite to the pen tip side of the hard coating portion 82E of the front end portion 8ET having a maximum diameter R5 toward the axial portion 8ES. Therefore, substantially, the length of the front end portion 8ET in the axial direction is greater than that of the front end portion 8T of the core 8, and the existence of the tapered portion 82Ee can make the core 8E less likely to bend.

[0122] It should be noted that the core 8E of the electronic pen 1E of the second other embodiment described above is formed into a structure in which the front end portion 8ET and the axial portion 8ES except the contact portion 8ETc are covered by a hard covering portion 82E, but is not limited to this structure, and can also be a core with the same structure as the aforementioned cores 8, 8A, 8B, 8C.

[0123] It should be noted that the structure of the electronic pen 1E and the core 8E of the second alternative embodiment described above can also be applied to electronic pens and cores using cores other than felt, and can be formed into a structure that prevents the core from bending. Figure 8 In the example of the core 8E, for example, an elastomer is used instead of the felt 81E, and POM is used as the hard coating 82E, for example, and the effect of preventing the bending of the core can also be expected.

[0124] [Other embodiments or modifications]

[0125] The above embodiments are all described with reference to the case where the electronic pen is of electromagnetic induction type, but the electronic pen and the electronic pen core of the present invention can also be applied to the case of the electronic pen and the electronic pen core of electrostatic capacitance type, especially the case of the electronic pen and the electronic pen core of active electrostatic capacitance type. However, in the case of the electronic pen and the electronic pen core of electrostatic capacitance type, the felt constituting the core is configured to have conductivity.

[0126] Description of Reference Numerals

[0127] 1, 1A…electronic pen, 2, 2A…housing (pen housing), 3, 311…coil, 4, 36…pen pressure detecting portion, 7…ferrite core, 7a…through hole, 8, 8A, 8B, 8C, 8D…core for electronic pen, 8T, 8AT, 8BT, 8CT, 8DT…front end portion, 8S, 8AS, 8BS, 8CS…axial portion, 8Tc, 8ATc, 8BTc, 8DTc, 8ETc…contact portion, 21, 21E…opening portion, 21a, 21Ea…inner circumferential wall surface, 21ae, 21Eae…end edge of opening, 81…felt, 82, 83…hard covering portion, 82t…conical portion.

Claims

1. An electronic pen, characterized in that: have: The housing has an opening portion having a columnar space with a center line direction in the axial direction and a length in the axial direction of a predetermined length on the pen tip side at one end side in the axial direction, and has a hollow portion in the interior that communicates with the columnar space in the opening portion; A pen pressure detection unit, disposed in the hollow portion of the housing; and The core body has a front end portion at one end side in the axial direction, which can partially protrude from the opening on the pen tip side of the columnar space in the opening portion of the shell, and the other end side in the axial direction is assembled relative to the writing pressure detection portion arranged in the hollow portion of the shell in a state that the writing pressure applied to the front end portion can be transmitted. The front end portion of the core body is composed of fibers bundled in the axial direction, and the contact portion that contacts the input surface of the position detection sensor is formed in a state where the fibers bundled in the axial direction are exposed, and at least a portion of the front end portion that faces the inner circumferential wall of the opening portion on the pen tip side of the shell is covered with a material that is harder than the fibers bundled in the axial direction.

2. The electronic pen according to claim 1, characterized in that: The core body includes the front end portion and an axial portion, and the axial portion is fitted directly or indirectly via a writing pressure transmission member to the writing pressure detection portion disposed in the hollow portion of the housing.

3. The electronic pen according to claim 1, characterized in that: The fibers bundled in the axial direction are felt.

4. The electronic pen according to claim 3, characterized in that: The axial core portion is formed of a felt integrally formed with the felt forming the front end portion. The felt is formed by compressing and fixing a felt raw material in an axial direction.

5. The electronic pen according to claim 2, characterized in that: The front end portion of the core body is configured to be thicker than the axial center portion.

6. The electronic pen according to claim 2, characterized in that: The through hole of the magnetic core around which the coil is wound is inserted into the axial center portion of the core body, and An end portion of the axial portion of the core body, which is inserted through the through hole of the magnetic core, is fitted to the writing pressure detection unit directly or indirectly via a writing pressure transmission member.

7. The electronic pen according to claim 1, characterized in that: The thickness of the hard material in the portion covered with the material harder than the fibers bundled in the axial direction is a predetermined thickness, and is configured to gradually become thinner toward the contact portion on the pen tip side of the portion.

8. The electronic pen according to claim 1, characterized in that: The pen tip side of the housing is formed into a tapered portion in which an inner peripheral edge of an opening of the columnar space of the opening portion on the pen tip side gradually tapers toward the inner peripheral edge of the opening.

9. The electronic pen according to claim 8, characterized in that: The tapered portion includes a first tapered portion whose thickness gradually decreases from the maximum diameter of the housing and a second tapered portion whose thickness gradually decreases closer to the pen tip than the first tapered portion.

10. The electronic pen according to claim 9, characterized in that: An inclination angle of the second tapered portion with respect to the axial direction is larger than an inclination angle of the first tapered portion with respect to the axial direction.

11. A core body for an electronic pen, having a front end portion at one end side in the axial direction that can partially protrude from an opening portion on the pen tip side of a housing of the electronic pen to the outside, and the other end side in the axial direction is assembled relative to a writing pressure detection portion arranged in a hollow portion of the housing in a state that the writing pressure applied to the front end portion can be transmitted, characterized in that: The front end portion is composed of fibers bundled in the axial direction, and the contact portion that contacts the input surface of the position detection sensor is formed in a state where the fibers bundled in the axial direction are exposed, and at least a portion of the front end portion that is facing the inner circumferential wall of the opening portion on the pen tip side of the shell is covered with a material that is harder than the fibers bundled in the axial direction.

12. The electronic pen core according to claim 11, characterized in that: The housing includes the front end portion and an axial portion, and the axial portion is fitted directly or indirectly via a writing pressure transmission member to the writing pressure detection portion disposed in the hollow portion of the housing.

13. The electronic pen core according to claim 11, characterized in that: The fibers bundled in the axial direction are felt.

14. The electronic pen core according to claim 13, characterized in that: The axial core portion is formed of a felt integrally formed with the felt forming the front end portion. The felt is formed by compressing and fixing a felt raw material in an axial direction.

15. The electronic pen core according to claim 12, characterized in that: The front end portion is configured to be thicker than the axial center portion.

16. The electronic pen core according to claim 12, characterized in that: A tapered portion whose thickness gradually increases from the axial portion toward the front end portion is formed at a boundary between the front end portion and the axial portion.

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