Electronic pen

Abstract

The present invention makes it possible to effectively prevent moisture, such as saliva, from invading from a gap between a core body and a case at the tip portion of an electronic pen without complicating the structure and reducing the function of the electronic pen. An annular elastic member (16) is provided between a front end surface (22Px) of a protrusion (22P) provided on an inner wall surface in the vicinity of an opening (H) of a housing (2) and a rear end surface (Ptx) of a pen tip (Pt) of a core (4) attached inside the housing (2) so that a shaft (St) of the core (4) passes through the annular elastic member (16). The ring-shaped elastic member (16) has a small opening on the tip side and a large opening on the rear end side, so that the side surface thereof is inclined. The annular elastic member (16) fills a gap (gap) generated between the pen tip portion of the core and the housing, and prevents liquid from entering from the outside. In addition, due to the shape of the annular elastic component (16), the sliding movement of the core body corresponding to the pen pressure is not hindered.

Description

Technical Field

[0001] The present invention relates to an electronic pen used as a position indicator for a position detection device mounted on an information processing device such as a tablet PC (Personal Computer), for example. Background Art

[0002] In the core of an electronic pen, in addition to a core formed of a hard resin such as POM (polyoxymethylene), there is also a core formed by bundling synthetic fibers, and having elasticity by providing gaps between the synthetic fibers in the axial direction. In addition, there is also a core formed by a synthetic resin such as plastic, and having elasticity by providing pores of various shapes in the axial direction. In the case of the above-mentioned elastic core, if it comes into contact with a protective material such as resin or glass on the position detection surface of the position detection sensor, a soft touch can be obtained, and the electronic pen (core) can also be prevented from sliding on the protective material.

[0003] In recent years, tablet PCs using electronic pens have been increasingly adopted in learning systems for children and students. For a long time, elementary school children have developed "habits" such as biting, holding, and licking their pens. These habits also apply to electronic pens, with some children biting, holding, or licking them. Biting, holding, or licking the protruding side of the pen's core is thought to cause saliva to seep into the pen through the opening where the core protrudes. Because electronic pens contain electronic circuitry, moisture intrusion can cause them to malfunction or even malfunction.

[0004] In particular, as mentioned above, in the case of a core formed from bundled synthetic fibers with axially spaced pores, or a core formed from synthetic resin with axially spaced pores, saliva easily enters the electronic pen body through these pores and pores due to capillary action. Therefore, Patent Document 1, discussed below, discloses an invention relating to a core for an electronic pen in which bitter components are allowed to penetrate into a core formed from bundled synthetic fibers with axially spaced pores, or a core formed from synthetic resin with axially spaced pores. This invention is expected to prevent the bitter taste that would otherwise be experienced when biting, licking, or holding the pen.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-185653 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] If a person experiences a bitter taste when biting, holding, or licking an electronic pen, this "habit" can be gradually stopped. Therefore, the invention disclosed in Patent Document 1 is a useful technology from the perspective of protecting electronic pens. However, as mentioned above, biting, holding, or licking an electronic pen is a "habit," and even a painful experience like this rarely leads to immediate cessation. Therefore, even if a person experiences a bitter taste, the "habit" of biting, holding, or licking the electronic pen will persist for a certain period of time, during which time saliva may enter the pen through the gap between the core at the tip of the pen and the housing.

[0010] Furthermore, the core of an electronic pen can be made not only of bundled synthetic fibers with axially spaced pores or synthetic resins with axially pores, but also of hard resins such as POM and other materials. In this case, repeated biting, licking, and chewing of the electronic pen can lead to the entry of saliva through the gap between the core at the tip of the pen and the housing. Furthermore, in addition to the aforementioned "habitual" behavior, preventing moisture from entering through the gap between the core at the tip of the pen and the housing is also crucial for electronic pens equipped with electronic circuitry. However, adding waterproofing must avoid complicating the structure or compromising the pen's functionality.

[0011] In view of the above circumstances, an object of the present invention is to effectively prevent moisture such as saliva from entering through the gap between the core and the housing at the tip of the electronic pen without complicating the structure or reducing the functionality of the electronic pen.

[0012] Means for solving problems

[0013] In order to solve the above-mentioned problem, an electronic pen is provided, characterized by comprising: The housing is a cylindrical body having an opening at the front end, and has an annular protrusion protruding from the inner wall surface near the opening toward the axis, and is equipped with circuit components; The core body is a rod-shaped body composed of a pen tip and a shaft extending from a rear end surface of the pen tip, wherein the central axis of the pen tip is the same as the central axis of the shaft, and the area of ​​the rear end surface of the pen tip is larger than the area of ​​the front end surface of the shaft; and The annular elastic member is an annular member, which is arranged in a manner for allowing the shaft portion to pass through, at a portion where the front end face of the protrusion of the shell and the rear end face of the pen tip portion of the core body are opposite to each other when the core body is inserted from the rear end side through the opening portion of the shell and the rear end portion of the core body is installed in the shell. The opening on the pen tip side is small and the opening on the rear end side is large, so that the side surface is inclined.

[0014] According to the electronic pen of the present invention, an annular elastic member is provided between the front end face of a protrusion provided on the inner wall surface near the opening of the housing and the rear end face of the pen tip of the core body installed in the housing so that the shaft of the core body can pass through. The opening on the pen tip side of the annular elastic member is small and the opening on the rear end side is large, so that the side is inclined. The annular elastic member fills the gap (void) generated between the pen tip of the core body and the housing to prevent liquid from invading from the outside. In addition, due to its shape, the annular elastic member does not hinder the sliding movement of the core body corresponding to the writing pressure, can appropriately transmit the writing pressure, and will not reduce the function of the electronic pen. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a diagram for explaining a configuration example of an electronic pen according to an embodiment.

[0016] Figure 2 It is a diagram for explaining the main parts of the electronic pen according to the embodiment.

[0017] Figure 3 This is a diagram for explaining an annular elastic member and the like used in the electronic pen according to the embodiment.

[0018] Figure 4 This is a diagram for explaining the main parts of the electronic pen according to the second embodiment.

[0019] Figure 5 is shown by using Figure 4 Graph showing a hysteresis curve of writing pressure detected by an electronic pen constructed with an annular elastic member as shown. DETAILED DESCRIPTION

[0020] An embodiment of the electronic pen according to the present invention will be described below with reference to the accompanying drawings. The following embodiment is described using an active capacitive electronic pen, which transmits a signal from the electronic pen and detects the indicated position based on the position of a position detection sensor that receives the signal.

[0021] [First embodiment]

[0022] <Structural Example of an Active Capacitive Electronic Pen>

[0023] Figure 11 is a diagram for explaining an example of the structure of the electronic pen 1 according to the present embodiment, and is a diagram showing the interior of the electronic pen 1 by cutting away a portion of the outer shell (housing) 2 for the purpose of explanation. Figure 2 1 is a diagram for explaining the main parts of the electronic pen 1. Specifically, Figure 2 (A) is in Figure 1 FIG1 is an enlarged cross-sectional view of the main part of the pen tip side of the electronic pen 1 not shown. Figure 2 (B) is a diagram schematically showing a portion of the electronic pen 1 that implements the functions of writing pressure detection and signal transmission.

[0024] like Figure 1 As shown, the electronic pen 1 includes a housing (casing) 2. This housing 2 is cylindrical and elongated in the axial direction (along the axis), has an opening on one axial side, and is closed on the other axial side. This housing 2 is made of a conductive material, in this example, anodized aluminum, and comprises a cylindrical housing body 21 with a hollow interior, and a front cover 22 and a rear cover 23 coupled to this housing body 21. The front cover 22 and rear cover 23 are fitted into the housing body 21 to form the housing 2.

[0025] like Figure 2 As shown in (A), the front cover 22 is a cylindrical structure having a through hole 22a in the axial direction, and the outer shape of the portion on the pen tip side of the electronic pen 1 is a tapered shape with the outer diameter decreasing as it approaches the pen tip. The end of the front cover 22 on the pen tip side forms the opening H of the through hole 22a. In the hollow portion of the housing 2, as shown in FIG. Figure 1 As shown, a substrate holder 3 and a battery 5 for holding components such as a printed circuit board 8 are housed. Figure 2 As shown in FIG. 1 (A), a core holder (core holding portion) 6 and a pressure-sensitive member (writing pressure detection portion) 7 are housed.

[0026] In addition, if Figure 2 As shown in (A), an annular protrusion 22P extending toward the axis is provided on the inner wall surface near the opening H of the front cover 22. That is, an annular protrusion 22P extending toward the inside is provided on the inner wall surface of the front cover 22 slightly closer to the rear end than the opening H. Figure 2 As shown in FIG. 2A , the portion of the front cover 22 closer to the opening H than the front end surface 22Px of the protrusion 22P serves as a cup-shaped portion into which the rear end of the pen tip Pt of the core body 4, described later, fits. It should be noted that the edge of the protrusion 22P on the pen tip side is cut away obliquely to facilitate insertion of the core body 4 into the housing 2.

[0027] And, as Figure 1 and Figure 2As shown in (A), the core 4 is inserted into the through hole 22a through the opening H of the front cover 22 and mounted relative to the core holder 6 inside the housing 2. In addition, the core 4 can also be removed from the core holder 6. In other words, the core 4 can be loaded and unloaded relative to the housing 2. As will be described in detail later, the core 4 is composed of a core rod 41 formed of a conductive material and a protective member 42 formed of a non-conductive material, and its appearance is roughly divided into two parts: the pen tip Pt and the shaft St.

[0028] The substrate holder 3 is made of an insulating resin, such as a liquid crystal polymer, and has the following structure: when housed in the hollow portion of the housing 2, the substrate holder 3 is Figure 2 As shown in (A), the pressure-sensing component holder 3a and the printed circuit board mounting base 3b are continuous in the axial direction of the electronic pen 1. The pressure-sensing component holder 3a is a cylindrical member with a hollow portion for housing the pressure-sensing component 7 (multiple components for detecting writing pressure). Its outer diameter is smaller than the inner diameter of the through-hole 22a of the front cover 22. The printed circuit board mounting base 3b is a boat-shaped member that mounts and holds the printed circuit board 8. Specifically, it is a member formed by cutting a cylindrical body approximately in half along the axial direction.

[0029] The substrate holder 3 houses the pressure-sensitive component holding portion 3a and the printed circuit board mounting table portion 3b as a whole in the housing 2 so that the pressure-sensitive component holding portion 3a faces the core 4 side and is fixed so as not to move. Figure 2 As shown in (A), the core holder 6 for holding the core 4 is combined with the pressure-sensitive component holding portion 3a of the substrate holder 3, and the pressure (pen pressure) applied to the core 4 is mainly from the core rod 41, which is transmitted to the pressure-sensitive component 7 in the pressure-sensitive component holding portion 3a.

[0030] like Figure 1 As shown, a terminal conductor 51 is provided at the end of the printed circuit board mounting base portion 3b of the substrate holder 3 on the side opposite to the pressure-sensing component holding portion 3a. This terminal conductor 51 electrically contacts the positive terminal 5a of the battery 5 and is electrically connected to the copper foil pattern of the power supply line of the printed circuit board 8. A coil spring terminal 52 made of conductive metal is provided at the fitting portion of the rear cover 23 that fits with the housing body 21 and is electrically connected to the negative terminal 5b of the battery 5. Figure 1 As shown, the battery 5 is inserted into the case 2 with the positive terminal 5a connected to the terminal conductor 51. Then, the rear cover 23 is fitted to the case body 21 with the coil spring terminal 52 pressing the negative terminal 5b of the battery 5.

[0031] In this embodiment, the housing body 21, which is made of a conductive material, is electrically connected to the ground conductor of the printed circuit board 8. Since the rear cover 23 and the housing body 21 are made of a conductive material, the negative terminal 5b of the battery 5 is electrically connected to the ground conductor of the printed circuit board 8 via the rear cover 23 and the housing body 21. Meanwhile, the positive terminal 5a of the battery 5 is connected to the copper foil pattern of the power supply line on the printed circuit board 8 via the terminal conductor 51. This allows the voltage of the battery 5 to be supplied as the power supply voltage to the circuits formed on the printed circuit board 8.

[0032] The printed circuit board 8 is equipped with a circuit section consisting of a signal generating circuit 8S, an integrated circuit (IC) 10, and its peripheral circuit components. The signal generating circuit 8S generates the signal transmitted from the core 41 of the electronic pen 1. The IC 10 constitutes a control circuit that controls the transmission of the signal from the signal generating circuit 8S to the core 41. The peripheral circuit section includes push switches (side switches) 11 and 12. Furthermore, a conductive terminal member 14 connecting the core 41 to the signal generating circuit 8S and a conductive terminal member 15 that transmits the detection output of the writing pressure from the pressure-sensing component 7 are connected to the printed circuit board 8.

[0033] like Figure 2 As shown in (A), the core 4 is fitted into the core holder 6 made of a conductive material via the conductive elastic member 9, thereby being coupled and held relative to the core holder 6. Furthermore, the core holder 6 is fitted into the holding member 73 of the pressure-sensing component 7 within the pressure-sensing component holding portion 3a of the substrate holder 3, thereby transmitting the pressure (writing pressure) applied to the core 4 to the pressure-sensing component 7.

[0034] In this case, the core holder 6 is configured so that a coil spring 13, an example of an elastic member made of a conductive material such as a conductive metal, is disposed between the core holder 6 and the substrate holder 3 and constantly biases the core rod 41 relative to the substrate holder 3. It should be noted that the coil spring 13, together with the conductor terminal member 14, constitutes an electrical connection member for transmitting signals from the signal generating circuit 8S, which is controlled and sent by the IC 10 disposed on the printed circuit board 8, to the core rod 41. Therefore, a metal plate 13a is provided at the pen tip-side end of the pressure-sensing component holding portion 3a of the substrate holder 3. This metal plate 13a electrically connects the coil spring 13 and the conductor terminal member 14.

[0035] That is, Figure 2As shown in FIG. 8B , the signal from the signal generating circuit 8S proceeds in the order of the conductor terminal member 14 → the metal plate 13a → the coil spring 13 → the core holder 6 → the core rod 41, and is transmitted from the core rod 41. The conductor terminal member 14, the coil spring 13, the metal plate 13a, the core holder 6, and the core rod 41 constitute electrical connection members, forming a transmission path for the position indication signal from the signal generating circuit 8S of the printed circuit board 8.

[0036] The pressure sensing member (writing pressure detecting unit) 7 of this embodiment is a case where a variable capacitor whose electrostatic capacitance changes according to the writing pressure applied to the core 4 is used. Figure 2 As shown in (A), the pressure-sensing component 7 is composed of multiple components: a dielectric 71, a terminal member 72, a retaining member 73, a conductive member 74, and an elastic member 75. The terminal member 72 is made of a conductive material and constitutes the first electrode of the variable-capacitance capacitor formed by the pressure-sensing component 7. Furthermore, the conductive member 74 is made of, for example, conductive rubber, and the elastic member is a coil spring made of a conductive material. The conductive member 74 and the elastic member 75 are electrically connected to form the second electrode of the variable-capacitance capacitor.

[0037] As a result, the electrostatic capacitance of the variable capacitance capacitor formed between the terminal member 72 constituting the first electrode and the conductive member 74 constituting the second electrode changes according to the pressure applied to the core rod 41. The change in the electrostatic capacitance of the variable capacitance capacitor is supplied from the pressure-sensing component 7 to the IC 10 provided on the printed circuit board 8 via the conductive terminal member 15, and the writing pressure is detected by the IC 10. In other words, the IC 10 is a control circuit that controls the transmission of the signal from the signal generating circuit 8S to the core rod 41, and functions as a writing pressure detection unit that detects (calculates) the writing pressure applied to the core body 4 based on the output signal from the pressure-sensing component 7. As a result, the writing pressure information can be included in the signal transmitted via the core rod 41 and transmitted.

[0038] In the electronic pen 1 of this embodiment, as Figure 2 As shown in (A), the core 4 is mounted on the core holder 6 inside the housing 2 and can move in the axial direction. Thus, the core 4 is pushed into the housing 2 according to the writing pressure applied to the core rod 41 by the user, and accordingly, the core rod 41 and the core holder 6 press the pressure-sensitive component 7 to detect the writing pressure. In addition, when the writing pressure applied to the core rod 41 is released, the core holder 6 and the core 4 can be restored to their original positions by the action of the coil spring 13. Figure 2 The initial state shown in (A).

[0039] IC10 of electronic pen 1 is controlled so that it sends a burst signal (position indication signal) for coordinate detection (position detection) corresponding to the signal from signal generating circuit 8S to the position detection sensor. This allows the position detection sensor to detect the position indicated by electronic pen 1 on the position detection sensor. Furthermore, within the circuitry including IC10, which is included in the printed circuit board 8 of electronic pen 1, while the burst signal is being sent, an operation is performed to detect the writing pressure based on the electrostatic capacitance of pressure-sensing component 7. After the burst signal transmission period ends, IC10 transmits a coded signal from core rod 41, obtained by modulating the signal from signal generating circuit 8S according to the detected writing pressure, to notify the position detection sensor of the writing pressure. This allows the position detection sensor to detect the writing pressure applied to core body 4 of electronic pen 1.

[0040] Thus, the electronic pen 1 of this embodiment achieves the following functions: indicating the position on the position detection sensor to the position detection sensor, detecting the writing pressure applied to the core rod 41, and notifying the position detection sensor of the writing pressure. Furthermore, the electronic pen 1 of this embodiment enables the position detection sensor to appropriately detect the tilt of the electronic pen 1 based on the signal sent from the conductive core rod 41.

[0041] <Structural Example of Core 4>

[0042] like Figure 2 As shown in (A), the core body 4 is composed of a core rod 41 and a protective member 42. The core rod 41 is a conductive rod-shaped body. In this embodiment, the core rod 41 is formed using a conductive elastomer. The conductive elastomer is a highly insulating rubber material that is roughly evenly mixed with conductive particles (carbon, metal powder, metal vapor deposition powder, etc.) in a certain mixing ratio to add conductive rubber. Therefore, the core rod 41 is a soft member with elasticity, which realizes the so-called soft writing feel of the pen tip.

[0043] like Figure 2 As shown in (A), the protective member 42 covers the side surfaces of the middle portion of the mandrel 41, excluding the front and rear ends, to protect the mandrel 41. In this embodiment, the protective member 42 is made of polycarbonate. Polycarbonate is a type of thermoreversible plastic that softens when heated and can be formed into a desired shape, and solidifies when cooled.

[0044] Therefore, when forming the core body 4, a core rod 41 made of a conductive elastomer is first molded. Then, a protective member 42 (secondary side) is formed by injecting polycarbonate into the same mold with respect to the core rod 41 (primary side). This is known as two-color molding. This allows the core body 4 to be formed with the protective member 42 provided on the side surface of the middle portion of the core rod 41. Two-color molding is also known as heterogeneous material molding or dual molding.

[0045] As described above, the core 4 is a rod-shaped body that is roughly divided into two parts: the pen tip Pt and the shaft St. The pen tip Pt constitutes the pen tip of the electronic pen 1. Figure 2 As shown in (A) and (B), it is a portion that gradually tapers toward the front end and becomes tapered (approximately conical), and the arc-shaped front end of the core rod 41 protrudes from its apex. The shaft portion St is the portion extending rearward from the rear end surface of the pen tip portion Pt.

[0046] from Figure 2 As can be seen from (A) and (B), the central axis of the pen tip Pt is the same as the central axis of the shaft St, and the area of ​​the rear end face of the pen tip Pt is larger than the area of ​​the front end face of the shaft St. Therefore, the rear end face Ptx of the pen tip Pt is exposed in an annular shape except for the joint portion with the shaft St. In addition, a shaft protrusion 43 is provided on the side of the shaft St. Figure 2 As shown in (A) and (B) of FIG. , the shaft protrusion 43 is inclined so as to become lower toward the rear end. Therefore, when the core 4 is inserted through the opening H and installed in the housing 2, the shaft protrusion 43 of the core 4 will abut against the protrusion 22P of the front cover 22 of the housing 2. However, the inclination of the shaft protrusion 43, which becomes lower from the pen tip toward the rear end, allows the core 4 to be pushed into the housing 2 relatively smoothly and installed in the core holder 6.

[0047] On the other hand, Figure 2 As shown in FIG. 5A , after the core 4 is mounted on the core holder 6, the front end face 43y of the shaft protrusion 43 and the rear end face 22Py of the protrusion 22P in the front cover 22 are in a state of facing and engaging with each other. Therefore, even if the core 4 mounted on the core holder 6 in the housing 2 is to be removed from the housing 2, it cannot be easily removed because the front end face 43y of the shaft protrusion 43 and the rear end face 22Py of the protrusion 22P are engaged with each other.

[0048] Therefore, a child, for example, cannot easily pull out the tip Pt of the core 4 by biting it with their teeth. However, by grasping the tip Pt of the core 4 attached to the core holder 6 with a fingernail or other device and carefully applying force, it can be removed (disassembled). Therefore, the core 4 can be replaced as needed. Furthermore, by attaching the annular elastic member 16 to the core 4, moisture is prevented from entering through the tip of the electronic pen 1, improving its waterproofness.

[0049] That is, Figure 2 As shown in FIG. 1A , in the case of the electronic pen 1 of this embodiment, an annular elastic member 16 is disposed between the core 4 and the housing 2. The annular elastic member 16 is formed into an annular shape by providing a through hole in a circular elastic member. The diameter of the opening of the through hole of the annular elastic member 16 on the pen tip side is short, and the diameter of the opening on the rear end side is long. Therefore, the side surface is inclined, and the cross section of the annular elastic member 16 is as follows: Figure 2 The annular elastic member 16 functions to block the gap (space) between the core 4 and the housing 2 at the front end of the electronic pen 1, thereby preventing moisture from entering.

[0050] Specifically, the presence of the annular elastic member 16 prevents saliva from entering the interior of the electronic pen 1, even if a child bites, holds, or licks the pen tip of the electronic pen 1. Furthermore, even if water or tea is spilled onto the pen tip of the electronic pen 1, the water, tea, or other substance cannot enter the interior of the electronic pen 1. Furthermore, the use of the annular elastic member 16 with inclined side surfaces allows for appropriate detection of writing pressure without hindering the axial sliding movement of the core 4 in response to the writing pressure. The following describes in detail the structure of the pen tip of the electronic pen 1, including the annular elastic member 16.

[0051] <Use of the annular elastic member 16>

[0052] Figure 3 1 is a diagram for explaining the annular elastic member 16 and the like used in the electronic pen 1. Specifically, Figure 3 (A) is an enlarged cross-sectional view of the pen tip side portion of the electronic pen 1 provided with the annular elastic member 16. Figure 3 (B) is a perspective view of the annular elastic member 16 as viewed from the front side (pen tip side). Figure 3 (C) is a perspective view of the annular elastic member 16 as seen from the back side (rear end side).

[0053] In the annular elastic member 16 of this embodiment, as shown in FIG. Figure 3As shown in (B) and (C), the diameter of the opening on the front side (tip side) of the through hole 16H is shorter than the diameter of the opening on the back side (rear end side). Therefore, in the annular elastic member 16, the opening on the front side of the through hole 16H is small and the opening on the back side is large, so the side surface is inclined so as to open from the tip side toward the rear end, and the annular elastic member 16 is in the shape of a plate with the bottom detached. Therefore, in Figure 3 In the cross-sectional view of (A), the cross-sectional shape of the annular elastic member 16 is similar to Figure 2 The shape shown in (A) similarly expands from the pen tip side toward the rear end.

[0054] like Figure 3 As shown in (A), the annular elastic member 16 is installed on the core body 4 by passing the shaft portion St of the core body 4 through the through hole 16H of the annular elastic member 16. In this case, the annular elastic member 16 is installed at a position where the front surface of the annular elastic member 16 (the end surface on the pen tip side) contacts the rear end surface of the pen tip portion Pt of the core body 4. The core body 4 with the annular elastic member 16 installed is inserted from its rear end side through the opening H of the front cover 22 and installed in the core body bracket 6 in the housing 2. As a result, as shown in FIG. Figure 3 As shown in FIG. 2A , the annular elastic member 16 is located between the rear end surface Ptx of the pen tip Pt of the core 4 and the front end surface 22Px of the protrusion 22P of the front cover 22 of the housing 2 .

[0055] like Figure 3 As shown in FIG. 1A , the diameter Hw of the opening H of the front cover 22 of the housing 2 of the electronic pen 1 of this embodiment is 3.05 mm. Therefore, the diameter of the bottom surface of the pen tip Pt of the core 4 is slightly shorter than the diameter Hw of the opening H of the front cover 22. Figure 3 As shown in (A), the diameter Pw of the shaft portion St between the rear end face Ptx of the pen tip Pt of the core body 4 and the front end face 43y of the shaft protrusion 43 of the core body 4 is 1.8 mm. Therefore, the inner diameter of the protrusion 22P of the front cover 22 is slightly longer than the diameter Pw of the shaft portion St. Figure 3 As shown in (A), the core body 4 is installed in the housing 2. When not in use (when pen pressure is not applied to the core body 4), the distance Gw between the rear end face Ptx of the pen tip Pt of the core body 4 and the front end face 22Px of the protrusion 22P of the front cover 22 is 0.48 mm.

[0056] On the other hand, Figure 3As shown in FIG. 1A , the diameter (inner diameter) Ri of the front opening of the annular elastic member 16 is 1.75 mm, the outer diameter Ro of the rear end is 3.05 mm, and the height (the height from the lower surface to the upper surface of the through hole 16H) Rh is 0.5 mm. Therefore, the diameter (inner diameter) Ri of the front opening of the annular elastic member 16 is shorter than the diameter Pw of the shaft portion St of the core 4, and the height Rh of the annular elastic member 16 is longer than the distance Gw between the rear end surface Ptx of the pen tip Pt and the front end surface 22Px of the protrusion 22P of the front cover 22.

[0057] However, the annular elastic member 16 is formed of an elastic material that can be stretched. In this embodiment, the annular elastic member 16 is formed of, for example, silicone rubber with a hardness of A30. Therefore, when the annular elastic member 16 is mounted on the shaft St of the core 4, the opening portion of the pen tip side of the annular elastic member 16 can be stretched and easily mounted. After mounting, the annular elastic member 16 is in close contact with the shaft St. In addition, as Figure 2 (A) Figure 3 As shown in FIG. 1A , the annular elastic member 16 is attached to a position where the front end surface of the annular elastic member 16 contacts the rear end surface Ptx of the pen tip Pt of the core body 4 .

[0058] Furthermore, if Figure 3 As shown in (A), it is assumed that the core 4, to which the annular elastic member 16 is attached, is mounted on the core holder 6 within the housing 2. The outer diameter Ro of the rear end of the annular elastic member 16 is 3.05 mm, which is the same as the diameter Hw of the opening H of the front cover 22. Therefore, the side surface on the rear end side of the annular elastic member 16 contacts the inner wall surface of the opening H of the front cover 22. In addition, the distance Gw between the rear end surface Ptx of the pen tip Pt and the front end surface 22Px of the protrusion 22P of the front cover 22 is 0.48 mm.

[0059] In this case, the annular elastic member 16 is sandwiched between the rear end surface Ptx of the pen tip Pt of the core body 4 and the front end surface 22Px of the protrusion 22P. The annular elastic member 16 is compressed in the axial direction, contracts in the axial direction, and bulges in a direction intersecting the axial direction. As a result, the front end surface of the annular elastic member 16 is in close contact with the rear end surface Ptx of the pen tip Pt of the core body 4, and the rear end portion of the annular elastic member 16 is in close contact with the inner wall surface of the opening H of the front cover 22 and the front end surface 22Px of the protrusion 22P in the front cover 22.

[0060] In this way, when the core 4 equipped with the annular elastic member 16 is installed in the core support 6 in the housing 2, as shown in FIG. Figure 3 As shown in (A), the pen tip side portion of the annular elastic member 16 is in close contact with the rear end surface Ptx of the pen tip portion Pt of the core body 4 and the side surface of the shaft portion St of the core body 4. Figure 3As shown in FIG. 1A , the rear end portion of the annular elastic member 16 is in close contact with the front end surface 22Px of the protrusion 22P of the front cover 22 and the inner wall surface of the opening H of the front cover 22. As a result, the gap (clearance) between the front cover 22 and the core 4 on the pen tip side of the electronic pen 1 is completely blocked by the annular elastic member 16, preventing the inflow of moisture.

[0061] In addition, if Figure 3 As shown in (A), the side surface of the annular elastic member 16 is inclined. Therefore, the pen tip-side portion of the annular elastic member 16 can move in the axial direction, with the rear end portion of the annular elastic member 16, which is in close contact with the front end surface 22Px of the protrusion 22P of the front cover 22 and the inner wall surface of the opening H of the front cover 22, serving as a fulcrum. Therefore, when writing pressure is applied to the core 4, the core 4 can slide by being pushed into the housing 2, thereby appropriately transmitting the writing pressure to the pressure-sensing component 7. Consequently, the accuracy of writing pressure detection is not reduced.

[0062] In this specification, the hardness of silicone rubber, A30, refers to the hardness measured using an ISO (International Organization for Standardization) "Type A durometer." That is, A30 means a hardness of 30 degrees measured using a Type A durometer.

[0063] [Second embodiment]

[0064] In the annular elastic member 16 of the first embodiment described above, if Figure 3 As explained above, the diameter of the opening on the front side (tip side) of through-hole 16H is smaller than the diameter of the opening on the back side (rear end), resulting in a slanted side surface and the annular elastic member 16 being shaped like a plate with a detached bottom. Therefore, if excessive pressure is applied, a significant load is applied to the annular elastic member 16, potentially causing it to tilt backward (flip) or expand from the rear end toward the tip side, contrary to its normal state. In this case, there is a concern that the waterproofing effect may be reduced, and the accuracy of pen pressure detection may be impaired.

[0065] Therefore, in the electronic pen 1A of the second embodiment described below, a ribbed annular elastic member 16A is used to prevent the pen from tilting (flipping) even when a strong writing pressure is applied. Furthermore, in the electronic pen 1A of the second embodiment, the position of the protrusion 22AP provided near the opening AH on the pen tip side of the front cover 22A is designed so that even when the ribbed annular elastic member 16A is used, the writing pressure can be appropriately detected without decreasing the detection accuracy.

[0066] It should be noted that, in the electronic pen 1A of the second embodiment, the components other than the annular elastic member 16A and the protrusion 22AP of the front cover 22A are constructed similarly to those of the electronic pen 1 of the first embodiment described above. Therefore, in the figures used to illustrate the electronic pen 1A of the second embodiment, components identical to those of the electronic pen 1 of the first embodiment are denoted by the same reference numerals, and detailed descriptions of these components are omitted to avoid duplication.

[0067] Figure 4 1A is a diagram for explaining the main parts of the electronic pen 1A according to the second embodiment. Specifically, Figure 4 (A) is an enlarged cross-sectional view of the pen tip side portion of the electronic pen 1A according to the second embodiment, where the annular elastic member 16A is provided. Figure 4 (B) is a perspective view of the annular elastic member 16A as viewed from the front side (pen tip side). Figure 4 (C) is a perspective view of the annular elastic member 16A as seen from the back side (rear end side).

[0068] The annular elastic member 16A of the second embodiment is also formed into an annular shape by providing a through hole 16AH in a circular elastic member. Figure 4 As shown in (B) and (C), the diameter of the opening on the front side (tip side) of the through hole 16AH is shorter than the diameter of the opening on the back side (rear end side). Therefore, the annular elastic member 16A is also the same as the annular elastic member 16 of the first embodiment. The opening on the front side of the through hole 16AH is small and the opening on the back side is large, so the side surface is inclined. However, the annular elastic member 16A of the second embodiment is different from the annular elastic member 16 of the first embodiment. Figure 4 As shown in (B) and (C) of FIG. 1 , ribs r1 , r2 , r3 , and r4 are provided on the back side of the side surface (inner side of the side surface).

[0069] Rib is a word that means "rib", but in the field of mechanical parts, it means a reinforcing member provided to reinforce, for example, a flat plate portion or a thin wall portion. In the case of the annular elastic member 16A, as shown in FIG. Figure 4 As shown in FIG. 1A (C), ribs r1, r2, r3, and r4 are provided on the outer periphery of the rear side of the side surface of the annular elastic member 16A at four locations whose radii are offset by 90 degrees relative to the center of the through hole 16H. The annular elastic member 16A of the second embodiment, including the ribs r1, r2, r3, and r4, is integrally formed from silicone rubber having a hardness of A30.

[0070] In this manner, the annular elastic member 16A provided with the ribs r1, r2, r3, and r4 is also attached to the core 4 and used in the same manner as the annular elastic member 16 of the first embodiment. In the case of this annular elastic member 16A, the thickness of the annular elastic member 16A is reinforced by providing the ribs r1, r2, r3, and r4, so that the annular elastic member 16A does not warp backward (flip) even when a large writing pressure is applied to the core 4.

[0071] Figure 4 (A) shows the case where the surface including the ribs r4 and r2 is cut. Regarding the annular elastic member 16A portion, the upper side is the rib r4 and the lower side is the rib r2. Figure 4 In (A), if the portion of rib r4 is observed, the angle formed by the intersection of the side S1 and the extension of the side S2 of the cross section of rib r4 is 90 degrees (a right angle). The surface containing the side S1 of rib r4 is the surface opposite the front end surface 22APx of the protrusion 22AP of the front cover 22A, and the surface containing the side S2 of rib r4 is the surface in contact with the side surface of the shaft portion St of the core 4. In addition, the surface containing the hypotenuse of the cross section of rib r4 (the side connecting the other end of side S1 and the other end of side S2) becomes the inclined side surface of the annular elastic member 16A. The other ribs r1, r2, and r3 are also formed in the same way as rib r4.

[0072] like Figure 4 As shown in (A), the annular elastic member 16A is similar to the annular elastic member 16 of the first embodiment, and is installed on the core 4 by the shaft portion St of the core 4 penetrating the through hole 16AH of the annular elastic member 16A. The core 4 with the annular elastic member 16A installed is inserted from its rear end side through the opening AH of the front cover 22A and is installed in the core bracket 6 in the housing 2A, although not shown. In this case, the core 4 is installed in the core bracket 6 in the manner of Figure 2 As shown in (A). Figure 4 As shown in FIG. 1A , the annular elastic member 16A is located in a gap formed between the rear end surface Ptx of the pen tip Pt of the core body 4 and the front end surface 22APx of the protrusion 22AP of the front cover 22A.

[0073] It should be noted that, although details will be described later, in the second embodiment, a gap Gp is ​​provided as a clearance (gap) within the space formed between the rear end surface Ptx of the pen tip Pt and the front end surface 22APx of the protrusion 22AP of the front cover 22A. Therefore, the position of the front end surface 22APx of the protrusion 22AP is shifted toward the rear end in the axial direction compared to the protrusion 22P of the first embodiment.

[0074] In the case of the electronic pen 1A of the second embodiment, Figure 4As shown in (A), the diameter Hw of the opening AH of the front cover 22A is 3.05 mm. Therefore, the diameter of the bottom surface of the pen tip Pt of the core 4 is slightly shorter than the diameter Hw of the opening AH of the front cover 22A. Figure 4 As shown in FIG. 1A , the diameter Pw of the shaft portion St between the rear end surface Ptx of the pen tip Pt of the core body 4 and the front end surface 43y of the shaft protrusion 43 of the core body 4 is 1.8 mm. Therefore, the inner diameter of the protrusion 22AP of the front cover 22A is slightly longer than the diameter Pw of this portion of the shaft portion St.

[0075] On the other hand, Figure 4 As shown in (A), the length Ri between the relative ribs of the annular elastic member 16A (the inner diameter of the annular elastic member 16A) is 1.75 mm, and the outer diameter Ro of the rear end is 3.05 mm. Therefore, the length Ri between the ribs of the annular elastic member 16A is shorter than the diameter Pw of the shaft St of the core 4. However, the annular elastic member 16A is formed of silicone rubber with a hardness of A30. Therefore, when the annular elastic member 16A is installed on the shaft St of the core 4, the periphery of the through hole of the annular elastic member 16A is slightly stretched and tightly installed on the shaft St.

[0076] In this case, if Figure 4 As shown in (A), the annular elastic member 16A is installed at a position where the front end surface of the annular elastic member 16A contacts the rear end surface Ptx of the pen tip portion Pt of the core body 4. Figure 4 As shown in (A), the width Rt of the front end surface of the annular elastic member 16A, in a direction intersecting the axis, is approximately 0.25 mm, and this portion contacts the rear end surface Ptx of the pen tip Pt. Furthermore, the diameter Hw of the opening AH of the front cover 22A and the outer diameter Ro of the rear end of the annular elastic member 16A are both 3.05 mm. Therefore, the outer edge of the rear end of the annular elastic member 16A contacts the inner wall of the opening AH of the front cover 22A.

[0077] In this way, the annular elastic member 16A is installed so that it slightly extends around the through-hole, closely adhering to the side surface of the shaft St, and its front end surface contacts the rear end surface Ptx of the pen tip Pt of the core 4. Furthermore, the core 4, with the annular elastic member 16A attached, is mounted on the core holder 6 within the housing 2A. In this case, as described above, the outer edge of the rear end side of the annular elastic member 16A, which has the same diameter of 3.05 mm, contacts the inner wall surface of the opening AH of the front cover 22A. As a result, no gap (air gap) is created between the core 4 and the annular elastic member 16A, or between the inner wall surface of the opening AH of the front cover 22A and the annular elastic member 16A. Therefore, the annular elastic member 16A prevents moisture from entering through the pen tip of the electronic pen 1A.

[0078] In addition, if Figure 4 As shown in (A), the core 4 is installed in the housing 2A. When the core 4 is not in use (when the writing pressure is not applied to the core 4), the distance Gw between the rear end surface Ptx of the pen tip Pt of the core 4 and the front end surface 22APx of the protrusion 22AP of the front cover 22A is 0.7 mm. Therefore, the position of the front end surface 22APx of the protrusion 22AP of the front cover 22A is 0.7 mm. Figure 3 In the case of the front cover 22 of the first embodiment shown, the front cover 22 is retreated in the rear end direction by about 0.22 mm.

[0079] On the other hand, Figure 4 As shown in (A), the height Rh of the annular elastic member 16A (the height from the bottom to the top surface of the through hole 16AH) is 0.5 mm. Figure 4 As shown in FIG. 1A , when the electronic pen 1A of the second embodiment is not in use, a gap Gp of 0.2 mm is formed between the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP of the front cover 22A. This gap Gp serves as a compensation to prevent the so-called ink leakage phenomenon in the electronic pen 1A of the second embodiment.

[0080] Let's briefly explain the so-called ink leakage phenomenon in electronic pens. The pen pressure detection system of an electronic pen has so-called hysteresis. Hysteresis means that the state of a system changes depending not only on the currently applied force but also on the forces applied in the past. In the electronic pen 1A of the second embodiment, hysteresis occurs due to the physical properties of the annular elastic member 16A. That is, when pen pressure is applied to the core 4 of the electronic pen 1A of the second embodiment, compressing the annular elastic member 16A in the axial direction, even when the pen pressure is removed, the annular elastic member 16A does not immediately return to its original state, but gradually returns to its original state. This is because the annular elastic member 16A is provided with ribs r1, r2, r3, and r4, so the recovery speed to the original state is slower than that of the annular elastic member 16 of the first embodiment.

[0081] Therefore, even after applying pressure to the pen tip Pt of the electronic pen's core 4, the pressure detection output from the pressure-sensing component 7 does not immediately return to a zero level even after the pressure is released. Instead, it gradually recovers over a certain period of time. Consequently, even after the pressure is released, the pressure level may persist above the pressure determination threshold, allowing drawing by the drawing application to continue for a period of time. In this case, the electronic pen can draw even though no pressure is applied and the pen is simply positioned over the position detection sensor, giving the user the sensation of ink leaking from a writing instrument. This phenomenon, unique to electronic pens, is referred to as "ink leaking."

[0082] Figure 5is shown by using Figure 4 16A is a diagram showing a hysteresis curve of the writing pressure detected by the electronic pen. Figure 5 In FIG. 1 , the vertical axis represents the pressure (writing pressure) level (Pressure Level) applied to the core 4, and the horizontal axis represents the detection output (load (g)) of the writing pressure detected by the pressure-sensitive component 7. Figure 5 In the example, it is denoted as Load(g)). In addition, Figure 5 In the figure, curves A1 and A2 are hysteresis curves of the detection output of the writing pressure of the electronic pen 1A when not in use, with a gap Gp of 0.2 mm between the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP of the front cover 22A. Note that curve A1 represents the state when writing pressure is applied, and curve A2 represents the state when the writing pressure is released.

[0083] In addition, Figure 5 In the figure, curves B1 and B2 are hysteresis curves of the detection output of the writing pressure of the electronic pen when no gap Gp is ​​provided between the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP of the front cover 22A. In other words, curves B1 and B2 are hysteresis curves of the detection output of the writing pressure of the electronic pen when the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP of the front cover 22A are in contact when not in use. Curve B1 represents the state when writing pressure is applied, and curve B2 represents the state when the writing pressure is released.

[0084] First, if Figure 4 As shown in (A), consider the case of an electronic pen 1A with a 0.2mm gap Gp between the rear end face of the annular elastic member 16A and the front end face 22APx of the protrusion 22AP. In this case, when the electronic pen 1A is placed down and writing pressure is applied to the core 4, the core 4 is immediately pushed inward by the gap Gp toward the rear end of the electronic pen 1A. Therefore, the pressure-sensing component 7 is pressed almost simultaneously with the application of writing pressure, and the detection output of the writing pressure (load (g)) begins. Therefore, as shown in FIG. Figure 5 As shown by curve A1, where the medium pressure level is near 0 (zero), the pressure rises sharply, quickly generating a detection output (load (g)) of the writing pressure. Subsequently, the annular elastic member 16A is pressed and deformed by the writing pressure applied to the core 4. As the annular elastic member 16A deforms, the core 4 gradually presses the pressure-sensing component 7. Thus, as shown by curve A1, a detection output (load (g)) of the writing pressure is generated by the pressure-sensing component 7 in response to the applied writing pressure.

[0085] Afterwards, if the electronic pen 1A is lifted to release the writing pressure, the core 4 is immediately pushed toward the pen tip by the distance Gp due to the action of the coil spring 13. Figure 5 As shown in curve A2, the detection output (load (g)) of the writing pressure detected by the pressure-sensing component 7 begins to decrease. Thereafter, the annular elastic member 16A, which has been deformed by the applied writing pressure, gradually returns to its original state, and accordingly, the force pressing on the pressure-sensing component 7 is also released. As a result, the detection output (load (g)) of the writing pressure detected by the pressure-sensing component 7 converges to 0 (zero) g or its vicinity without hysteresis, as shown in curve A2. In other words, the presence of gap Gp achieves the effect of absorbing the hysteresis caused by the physical properties of the annular elastic member 16A.

[0086] In addition, if Figure 4 As shown in (A), the cross-section of the rib of the annular elastic member 16A is roughly triangular. In this case, if the surface including the side S2 is set as the bottom surface, the bottom surface is fixed to the shaft portion St of the core body 4, and the vertex portion opposite to the bottom surface is in contact with the inner wall surface of the opening portion AH of the front cover 22A. It can be considered that the contact portion is fixed by friction. As described above, the intrusion of moisture is prevented, and when the core body 4 slides and moves at an interval Gp, since the vertex portion is in contact with the inner wall surface of the front cover 22A, the side S2 in contact with the moving portion, i.e., the shaft portion St of the core body, does not generate a large friction force, and the core body 4 can be pushed in or pushed back in the axial direction relatively easily, which helps to properly detect the pen pressure.

[0087] Next, consider an electronic pen configured such that no gap Gp is ​​provided between the rear end face of the annular elastic member 16A and the front end face 22APx of the protrusion 22AP. In this case, when the electronic pen is placed down and pressure is applied to the core 4, the annular elastic member 16A is first pressed and deformed because there is no gap Gp. When the deformation of the annular elastic member 16A progresses to a certain extent, the core 4 is pushed in and presses the pressure-sensing component 7, thereby detecting the pressure. Figure 5 As shown by curve B1, where the medium pressure level is near 0 (zero), core 4 does not press pressure-sensing component 7 unless annular elastic member 16A deforms to a certain extent. Consequently, a time lag occurs between the application of writing pressure and the detection output (load (g)) of the writing pressure. Subsequently, as shown by curve B1, a detection output (load (g)) corresponding to the writing pressure applied to core 4 is obtained.

[0088] In addition, if the electronic pen is lifted to release the application of writing pressure, the writing pressure (load (g)) detected by the pressure-sensing component 7 will decrease, as shown in curve B2. Afterwards, the annular elastic member 16A, which has been deformed according to the applied writing pressure, gradually returns to its original state. Accordingly, the core 4 is also pushed back, and the force of the core 4 pressing the pressure-sensing component 7 is also released. However, even if the application of writing pressure is completely released (even if the applied writing pressure becomes 0 (zero)), the shape of the annular elastic member 16A does not immediately return to its original state but gradually recovers. Therefore, the detection output (load (g)) of the writing pressure detected by the pressure-sensing component 7 is shown in curve B2. Even if the level of applied writing pressure becomes 0 (zero), it does not become 0 (zero) g for a period of time, but is maintained at, for example, about 13.8 g.

[0089] Thus, the time from when the applied writing pressure reaches 0 (zero) until the detection output of the writing pressure (load (g)) converges to 0 (zero) is longer than when there is a gap Gp. Therefore, it is thought that the so-called "ink leakage phenomenon" in the electronic pen is more likely to occur. Therefore, in the electronic pen 1A of the second embodiment, if Figure 4 As described in (A) of FIG2 , when not in use, a gap Gp is ​​provided between the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP of the front cover 22A. This prevents the so-called "ink leakage" phenomenon in the electronic pen. Furthermore, because the presence of gap Gp allows the writing pressure applied to the core 4 to be immediately transmitted to the writing pressure detection unit 7, the pen responds more effectively to writing pressure than a pen without gap Gp.

[0090] As can be seen from the above description, in the electronic pen 1A of the second embodiment, an annular elastic member 16A is also provided between the rear end surface Ptx of the pen tip Pt of the core body 4 and the front end surface 22APx of the protrusion 22AP. This prevents the formation of a gap (clearance) between the core body 4 and the inner wall surface of the front cover 22A at the pen tip, thereby preventing moisture from entering through the pen tip.

[0091] In addition, if Figure 4 As shown in (C), the annular elastic member 16A is provided with ribs r1, r2, r3, and r4. This prevents the annular elastic member 16A from tilting backward (flipping) even when excessive pressure is applied, thereby preventing a decrease in waterproofing performance or pressure detection accuracy. Furthermore, the gap Gp provided between the rear end surface of the annular elastic member 16A and the front end surface 22APx of the protrusion 22AP prevents the so-called "ink leakage" phenomenon seen in electronic pens.

[0092] [Effects of the embodiment]

[0093] The electronic pens 1 and 1A of the first and second embodiments described above effectively prevent moisture, such as saliva, from entering through the gap between the core 4 and the outer casing 2 at the tip of the electronic pen, without complicating the structure or compromising the pen's functionality. This results in an electronic pen suitable for use by infants and children, who often bite, hold, or lick the pen tip. This electronic pen is ideal for use near water, such as swimming pools, rivers, lakes, and the seaside, and can also be used outdoors on rainy days.

[0094] [Modification]

[0095] <Material of the annular elastic member 16, 16A>

[0096] In the above embodiment, the annular elastic members 16 and 16A are described as being made of silicone rubber with a hardness of A30, but are not limited thereto. Alternatively, they may be formed using various elastic materials having a desired hardness. Therefore, the annular elastic members 16 and 16A can be formed using, for example, natural rubber, sponge, or various elastic resin materials. Furthermore, the annular elastic members 16 and 16A can be fixed to a predetermined position of the core 4 using an adhesive as needed.

[0097] <Modification of the Rib of the Annular Elastic Member 16A>

[0098] The number of ribs in the annular elastic member 16A is not limited to four. An appropriate number of ribs can be provided at various intervals along the circumference of the annular elastic member, such as four ribs at 120-degree intervals, two ribs at 180-degree intervals, or eight ribs at 45-degree intervals. Therefore, the size of the ribs can be appropriately adjusted based on the number of ribs provided. Furthermore, the intervals between the ribs do not necessarily need to be equal.

[0099] In addition, the ribs of the annular elastic member 16A do not need to be dispersed along the circumference of the annular elastic member, but can also be continuously arranged around the annular elastic member. In addition, the cross-section of the rib is not limited to being roughly triangular. The cross-section can also be, for example, circular. In short, ribs with various cross-sectional shapes can be provided, including portions that contact the shaft portion St of the core 4 and portions that contact the inner wall surface of the opening portion H, AH of the front cover 22, 22A. Furthermore, ribs with various cross-sectional shapes can be provided, including portions that contact the front end surfaces 22Px, 22APx of the protrusions 22P, 22AP of the front cover 22, 22A.

[0100] <Application to Various Electronic Pens>

[0101] In the above embodiment, the example of an active capacitance-based electronic pen 1 is used. However, electronic pens are not limited to active capacitance-based electronic pens. For example, the present invention can also be applied to electromagnetic induction-based electronic pens with a resonant circuit composed of an inductor (coil) and a capacitor. In short, the present invention can be applied to electronic pens that have a gap between the core and the outer shell (casing) on ​​the pen tip side, potentially allowing moisture to enter.

[0102] Description of labels

[0103] 1. 1A…Electronic pen, 2. 2A…Casing (housing), 21…Casing body, 22. 22A…Front cover, 22a…Through hole, H, AH…Opening, 22P, 22PA…Protrusion, 22Px, 22Apx…Front end surface, 22Py…Rear end surface, 23…Rear cover, 3…Substrate holder, 3a…Pressure-sensing component holder, 3b…Printed circuit board mounting base, 4…Core, 41…Core rod, Pt…Pen tip, Ptx…Rear end surface, St…Shaft, 42…Protective member, 43…Shaft protrusion, 43y…Front end surface, 5…Battery, 6…Core holder, 7…Pressure-sensing component, 8…Printed circuit board, 8S…Signal generating circuit, 9…Conductive elastic member, 10…IC, 13…Coil spring, 13a…Metal plate, 14…Conductive terminal member, 15…Conductive terminal member, 16…Elastic member

Claims

1. An electronic pen, characterized in that: have: The housing is a cylindrical body having an opening at the front end, has an annular protrusion protruding from the inner wall surface near the opening toward the axis, and carries circuit components; The core body is a rod-shaped body composed of a nib and a shaft extending from a rear end surface of the nib, wherein the central axis of the nib is the same as the central axis of the shaft, and the area of ​​the rear end surface of the nib is larger than the area of ​​the front end surface of the shaft; and The annular elastic member is an annular member, which is arranged in a manner that the shaft portion passes through, and is located at a portion where the front end face of the protrusion of the shell and the rear end face of the nib portion of the core body are opposite to each other when the core body is inserted from the rear end side through the opening portion of the shell and the rear end portion of the core body is installed in the shell. The opening on the nib side is small and the opening on the rear end side is large, so that the side surface is inclined.

2. The electronic pen according to claim 1, characterized in that: A rib is formed on the inner wall surface of the annular elastic member. The rib protrudes inward and has a portion in contact with the side surface of the shaft portion of the core and a portion in contact with the front end surface of the protrusion of the housing.

3. The electronic pen according to claim 1, characterized in that: A rib is formed on the inner wall surface of the annular elastic member. The rib protrudes inward in an annular shape along the inner circumference and has a portion in contact with the side surface of the shaft portion of the core and a portion in contact with the front end surface of the protrusion of the housing.

4. The electronic pen according to claim 1, characterized in that: A plurality of ribs are formed on the inner wall surface of the annular elastic member. The ribs are a plurality of portions protruding inwardly in a dispersed manner along the inner circumference, and each of the ribs has a portion contacting the side surface of the shaft portion of the core body and a portion contacting the front end surface of the protrusion portion of the shell.

5. The electronic pen according to claim 1, characterized in that: A plurality of ribs are formed on the inner wall surface of the annular elastic member. The plurality of ribs are a plurality of portions protruding inwardly in a dispersed manner along the inner circumference, and each of the ribs has a portion contacting the side surface of the shaft portion of the core body and a portion contacting the front end surface of the protrusion portion of the shell. When no writing pressure is applied to the core body, a gap is provided between the rib and the front end surface of the protrusion of the housing.

6. The electronic pen according to claim 1, characterized in that: A plurality of ribs are formed on the inner wall surface of the annular elastic member. The ribs are a plurality of portions protruding inwardly in a dispersed manner along the inner circumference, and each of the ribs has a first surface in contact with the side surface of the shaft portion of the core body and a second surface in contact with the front end surface of the protrusion portion of the shell. When a portion surrounded by the first surface, the second surface and the side surface of the annular elastic member is cut in the axial direction, the cross-section becomes a roughly triangular shape.

7. The electronic pen according to claim 1, characterized in that: A plurality of ribs are formed on the inner wall surface of the annular elastic member, and the plurality of ribs are a plurality of portions protruding inwardly in a dispersed manner along the inner circumference, and each of the ribs has a first surface in contact with the side surface of the shaft portion of the core body and a second surface in contact with the front end surface of the protrusion portion of the shell, and a cross section of a portion surrounded by the first surface, the second surface, and the side surface of the annular elastic member when cut in the axial direction becomes a substantially triangular shape, In a state where no writing pressure is applied to the core body, a gap is provided between the second surface of the rib and the front end surface of the protrusion of the housing.

8. The electronic pen according to claim 1, characterized in that: The annular elastic member is made of silicone rubber.

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