JP2024068615A - Electronic pen - Google Patents

Abstract

[Problem] To realize an electronic pen with waterproof and dustproof functions with a simple structure without compromising its function as an electronic pen. [Solution] A core body 4 is attached and held at its rear end to a core body holding member 5 inside a housing 2 so that its tip protrudes from an opening in a front cap 22 of the housing 2. Inside the housing 2, an electronic component that realizes the electronic pen function is provided behind the core body holding part 2, and a second electrode 13, which is a cylindrical internal component through which the core body 4 penetrates, is provided on the pen tip side inside the housing 2. A first ring-shaped elastic member 16 is provided so as to be in close contact with the entire circumference of the side surface of the second electrode 13 and the entire circumference of the inner wall surface of the front cap 22. Furthermore, a second ring-shaped elastic member 17 is provided so as to be in close contact with the entire circumference of the side surface of the core body holding member 5 and the entire circumference of the inner wall surface of the second electrode 13. [Selected Figure] Figure 2

Description

This invention relates to an electronic pen that functions as a position indicator for a position detection device mounted on an electronic device such as a tablet PC (Personal Computer).

For example, electronic devices such as tablet PCs are equipped with a position detection device. The position detection device is composed of a position detection sensor and a position detection circuit. The position detection sensor receives a position indication signal from the electronic pen, and the position detection circuit detects the position indicated by the electronic pen on the position detection sensor based on the output signal from the position detection sensor in response to the signal. Various electronic components are installed in the electronic pen. For example, the electronic pen may be equipped with a transmitter circuit that transmits a position indication signal, as well as a pressure detection unit (pen pressure detection unit) that detects the pressure (pen pressure) applied to the pen tip. In addition, the electronic pen may be equipped with a circuit that generates a tilt detection signal to enable detection of the tilt of the electronic pen, and electrodes that transmit the tilt detection signal. In addition, various electronic components such as a control IC and a power supply circuit are installed.

Electronic devices such as tablet PCs are easy to carry, so they can be used in various indoor locations, such as the kitchen, and are often taken outside for use. For this reason, some electronic devices such as tablet PCs are provided with waterproof and dustproof functions. For this reason, it is being considered to provide electronic pens used with electronic devices such as tablet PCs with waterproof and dustproof functions. Patent Document 1, which will be described later, discloses an invention relating to an electronic pen (position indicator) that is waterproof and dustproof. Specifically, Patent Document 1 discloses an invention relating to an electronic pen (position indicator) that covers the entire inner surface of the case in the circumferential direction and has an elastic portion disposed so as to close the opening of the case near the rear end of the core. By disposing the elastic portion so as to close the opening of the case, it is possible to prevent moisture and dust from entering the case through the opening.

Patent No. 6476140

The invention disclosed in the above-mentioned Patent Document 1 is an effective technology because it can provide waterproof and dustproof effects for an electronic pen with a simple configuration in which an elastic part is basically arranged to block the opening of the case. The invention disclosed in Patent Document 1 has a simple configuration, and is therefore suitable for application to extremely thin electronic pens used in smartphones, for example. However, when the invention disclosed in Patent Document 1 is applied to an electronic pen used in a tablet PC or the like, which is about the same size as a general ballpoint pen, the elastic part arranged to block the opening will also be large depending on the housing and the opening. In this case, since the elastic part acts directly on the core body, it may be difficult for the writing pressure applied to the core body to be transmitted to the writing pressure detection unit.

In view of the above, the object of the present invention is to realize an electronic pen that is waterproof and dustproof with a simple configuration without compromising its functionality as an electronic pen.

In order to solve the above problems,
A cylindrical housing with an opening on the pen tip side;
A rod-shaped core body,
a core holder provided in the housing and holding a rear end portion of the core body such that a front end portion of the core body protrudes from the opening of the housing;
an electronic component provided behind the core holder in the housing and realizing an electronic pen function;
a cylindrical internal component part through which the core body passes, on the pen tip side within the housing;
a first ring-shaped elastic member that is in close contact with the entire periphery of the side surface of the internal component and the entire periphery of the inner wall surface of the housing;
and a second ring-shaped elastic member that is in close contact with the entire periphery of the side surface of the core body holding portion and the entire periphery of the inner wall surface of the internal component.

According to the electronic pen of this invention, the core is attached and held at its rear end to a core holder provided in the housing so that its tip protrudes from the opening of the housing. Electronic components that realize the electronic pen function are provided in the housing behind the core holder. Also provided in the housing is a cylindrical internal component through which the core penetrates to the pen tip side. A first ring-shaped elastic member is provided so as to be in close contact with the entire circumference of the side of the internal component and the entire circumference of the inner wall surface of the housing. Furthermore, a second ring-shaped elastic member is provided so as to be in close contact with the entire circumference of the side of the core holder and the entire circumference of the inner wall surface of the internal component. These first ring-shaped elastic member and second ring-shaped elastic member prevent moisture and dust that enter through the opening of the housing from reaching the electronic components behind the core holder.

FIG. 2 is a diagram for explaining a configuration example of an electronic pen according to an embodiment; 2 is a diagram for explaining a main part of the pen tip side of the electronic pen according to the first embodiment; FIG. 4 is an enlarged cross-sectional view of a location where a second ring-shaped elastic member is provided in the electronic pen of the first embodiment; FIG. 4 is a diagram for explaining an equivalent circuit of the electronic pen according to the first embodiment; FIG. 10 is a diagram for explaining a main part of the pen tip side of another example of the electronic pen according to the first embodiment. FIG. 13 is a diagram for explaining a main part of the pen tip side of an electronic pen according to a second embodiment. FIG. 13 is a diagram for explaining a main part of the pen tip side of another example of the electronic pen according to the second embodiment. FIG.

Below, an embodiment of the electronic pen according to the present invention will be described with reference to the drawings. In the embodiment described below, an example will be described in which the electronic pen is applied to an active capacitance type electronic pen that indicates a position on a position detection sensor by transmitting a position indication signal formed by an installed transmission circuit toward the position detection sensor through a core body. Note that in the embodiment described below, the circuit that forms the position indication signal is called a "transmission circuit". This is because, not only is the signal generated by the oscillator used as the position indication signal as is, but the signal generated by the oscillator may also be subjected to various modulations, etc. to form a desired position indication signal and transmit it. For this reason, the term "transmission" is used, which broadly means sending out information.

[First embodiment]
<Configuration example of electronic pen 1>
Fig. 1 is a diagram for explaining an example of the configuration of an electronic pen 1 according to a first embodiment, showing the inside of a case (housing) 2 of the electronic pen 1 with a part cut away. Fig. 2 is a diagram (enlarged cross-sectional view) for explaining a main part of the pen tip side of the electronic pen 1. Fig. 3 is an enlarged cross-sectional view of an installation location of a second ring-shaped elastic member 17 of the electronic pen 1 according to the first embodiment, which will be described in detail later.

As shown in FIG. 1, electronic pen 1 has a case (housing) 2 that is elongated in the axial direction (direction along the axis) and has a cylindrical shape with one end in the axial direction facing the pen tip and having an opening, and the other end in the axial direction being closed. Case 2 is composed of a cylindrical case body 21 with a hollow space inside, and a front cap 22 and a rear cap 23 that are connected to case body 21. Case 2 is formed by fitting front cap 22 and rear cap 23 into case body 21.

As shown in FIG. 1, the hollow portion of the case 2 contains a board holder 3 for holding mounted components such as a printed circuit board 8, and a battery 9, and the pen tip side contains components for realizing the function of the electronic pen. The case body 21 and the rear cap 23 are made of a conductive material. In this embodiment, the case body 21 and the rear cap 23 are made of, for example, anodized aluminum. The front cap 22 is made of a non-conductive material. In this embodiment, the front cap 22 is made of, for example, plastic.

As shown in FIG. 1, a terminal conductor 91 is provided on the end of the board holder 3 opposite the pen tip side. This terminal conductor 91 electrically abuts against the positive terminal 9a of the battery 9 and is electrically connected to the copper foil pattern of the power line of the printed circuit board 8. A coil spring terminal 92 made of conductive metal is provided at the fitting portion of the rear cap 23 with the case body 21, and electrically connects to the negative terminal 9b of the battery 9. As shown in FIG. 1, the battery 9 is inserted into the case 2 so that the positive terminal 9a is connected to the terminal conductor 91. The rear cap 23 is then fitted into the case body 21 so that the coil spring terminal 92 presses against the negative terminal 9b of the battery 9.

In this embodiment, the case body 21, which is made of a conductive material, is electrically connected to the earth conductor of the printed circuit board 8. Because the rear cap 23 and the case body 21 are made of a conductive material, the negative terminal 9b of the battery 9 is electrically connected to the earth conductor of the printed circuit board 8 via the rear cap 23 and the case body 21. Meanwhile, the positive terminal 9a of the battery 9 is connected to the copper foil pattern of the power supply line of the printed circuit board 8 through the terminal conductor 91. This allows the voltage of the battery 9 to be supplied as the power supply voltage for the circuit formed on the printed circuit board 8.

On the printed circuit board 8, although not shown in FIG. 1, a circuit section consisting of a transmission circuit (signal generation circuit) 8s, a detection circuit 8d, a demodulation circuit 8r, a switch circuit SW, a control IC (Integrate Circuit) 10 shown in FIG. 1, and other peripheral circuit components is provided. The transmission circuit 8s generates a signal to be sent from the electronic pen core body (hereinafter referred to as the core body) 4 of the electronic pen 1 and a signal to be sent from the transmitting/receiving electrode 13 described later. The transmission circuit 8s can supply signals of different frequencies to the core body 4 and the transmitting/receiving electrode 13. The detection circuit 8d is for detecting the electrostatic capacitance of the pressure detection unit 6 described later in order to detect the writing pressure. The demodulation circuit 8r is for demodulating the signal received through the transmitting/receiving electrode 13 and supplying the information obtained thereby to the control IC 10.

As described below, the switch circuit SW switches, under the control of the control IC 10, whether to supply a signal from the transmission circuit 8s to the transmitting/receiving electrode 13 or to supply a signal received through the transmitting/receiving electrode 13 to the demodulation circuit 8r. The control IC 10 also constitutes a control circuit that controls each circuit section such as the transmission circuit 8s and the switch circuit SW. The peripheral circuit section includes push switches (side switches) 11 and 12 that are pressed down via operation sections 11a and 11b provided on the side of the case body 21, as shown in FIG. 1.

Although not shown in FIG. 1, the printed circuit board 8 is connected to a conductive wire that connects the core 4 to the transmitter circuit 8s, and a conductive wire that connects the transmitting/receiving electrode 13 to the switch circuit SW. The transmitting/receiving electrode 13 is connected to the transmitter circuit 8s and the demodulation circuit 8r via the switch circuit SW. Although not shown in FIG. 1, the printed circuit board 8 is connected to a conductive wire that connects the first and second electrodes of the pressure detection unit (pen pressure detection unit), which is configured as a variable capacitance capacitor (described in detail later), to the capacitance detection circuit 8d.

As shown in FIG. 2, the front cap 22 is configured as a cylindrical body having a through hole that passes through the core body 4 in the axial direction, and the external shape of the part on the pen tip side of the electronic pen 1 is tapered with the outer diameter decreasing toward the pen tip. The end of the front cap 22 on the pen tip side is the opening of the through hole that passes through the core body 4. As described above, the main parts for realizing the electronic pen function are mounted on the front cap 22 side.

As shown in FIG. 2, on the front cap 22 side of the case 2, the core body 4, the transmission member 5, and the pressure detection unit 6 are arranged in series in the axial direction with the same central axis. As shown in FIG. 2, the core body 4 is composed of a core rod 41 made of a conductive material and a protective member 42 made of a non-conductive material, and has a structure in which a space (air layer) 43 is provided between the core rod 41 and the protective member 42. In this case, the signal (electric field) radiated from the part of the egg-shaped pen tip part of the core rod 41 on the tip side beyond the wide part is radiated relatively efficiently only through the protective member 42.

However, the signal (electric field) emitted from the narrower part of the core rod 41 toward the rear end from the egg-shaped pen tip is suppressed by the action of the space 43 and the protective member 42. This is because the space 43 and the protective member 42 have different dielectric constants, and this part functions like a double capacitor. As a result, even if the electronic pen 1 is tilted, the core rod 41 can send an excellent position indication signal that does not become unnecessarily broad.

The transmission member 5 is composed of two separate members, a core body holding member 51 located on the pen tip side, and a pressing member 52 located behind the core body holding member 51. In the first embodiment, the core body holding member 51 and the pressing member 52 are formed of a non-conductive material, such as hard resin. The core body holding member 51 has a cup-shaped holding part 51a with a recess, and an extension part 51b that is attached to fit into the rear end side of the holding part 51a and extends in the opposite direction to the pen tip. A ring-shaped elastic member 51c having conductivity, such as conductive rubber, is fixed to the inner side surface of the recess of the holding part 51a. The elastic member 51c is designed to protrude (overhang) slightly from the inner side surface of the recess of the holding part 51a.

2, when the rear end of the core 4 is inserted into the recess of the holding portion 51a of the core holding member 51, the elastic member 51c tightens around the rear end of the core 4, allowing the core 4 to be attached to the core holding member 51. The core 4 can be removed from the core holding member 51 by, for example, hooking the nib portion of the core attached to the core holding member 51 with a fingernail and pulling it out. In this way, by providing a ring-shaped elastic member 51c on the inner side surface of the recess of the holding portion 51a of the core holding member 51, it is possible to attach the core 4 to the core holding member 51 and remove the core 4 from the core holding member 51.

As shown in FIG. 2, the core coil spring 41C is provided around the extension portion 51b of the core holding member 51. In other words, the extension portion 51b of the core holding member 51 passes through the central axis of the core coil spring 41C. In this case, one turn (one winding) of the core coil spring 41C on the holding portion 51a side fits into a recess provided on the side of the holding portion 51a of the core holding member 51, and the core coil spring 41C holds the core holding member 51. However, the core holding member 51 is not biased by the core coil spring 41C. In other words, the core holding member 51 is held in the case 2 while hanging from the core coil spring 41C.

Furthermore, the end of the core coil spring 41C on the pen tip side is connected to a conductive elastic member 51c provided on the holding portion 51a of the core holding member 51, and the other end is connected to h8s of the printed circuit board 8. In FIG. 2, the other end of the core coil spring 41C is constituted by the end of the extension wire (conductor wire) 41L of the core coil spring that extends from the core coil spring 41C. As a result, a position indication signal from the transmitting circuit 8s of the printed circuit board 8 is supplied to the core rod 41 of the core 4 through the core coil spring 41C and the elastic member 51c, and is transmitted from the core rod 41 of the core 4 to the position detection sensor.

The pressing member 52 is located behind the core body holding member 51. The pressing member 52 is mushroom-shaped and consists of a pressing head 52a located on the pressure detection unit 6 side and having a wide diameter, and a stem-shaped portion 52b that extends from the pen tip side end face of the pressing head 52a toward the pen tip side and has a shorter diameter than the pressing head 52a. The surface (rear end face) of the pressing head 52a opposite the pen tip side is a curved surface with its center at the apex. As shown in FIG. 2, when no writing pressure is applied to the core body 4, the core body 4, the core body holding member 51, and the pressing member 52 are located in series in the axial direction with the same axis. When writing pressure is applied to the core body 4 and it is pressed toward the rear end side of the electronic pen 1, the core body holding member 51 and the pressing member 52 are pressed toward the rear end side of the electronic pen 1, and the pressing member 52 presses the pressure detection unit 6.

As shown in FIG. 2, the end face of the stalk 52b of the pressing member 52 on the pen tip side is a convex curved surface with its apex at its center. Conversely, the end face of the rear end side of the extension 51b of the core holding member 51, which faces the end face of the stalk 52b on the pen tip side, is a concave curved surface with its apex at its center. As a result, when writing, writing pressure is applied to the pen tip of the core 4 in a direction that intersects with the axial direction, and even if the core 4 and the core holding member 51 are slightly tilted, the writing pressure applied to the core 4 can be properly transmitted to the pressure detection unit 6 via the pressing member 52 without attenuation.

The pressure detection unit 6 is a variable capacitance capacitor formed by a circular flat first electrode 61 facing one side of a circular flat dielectric 63 via a ring-shaped spacer 62, and a flat second electrode 64 attached to the other side of the dielectric 63. The first electrode 61 is formed of a conductive elastic material such as conductive rubber. Therefore, when writing pressure is applied to the core body 4 attached to the core body holding member 51, the first electrode 61 of the pressure detection unit 6 is pressed by the pressing member 52 pressed by the core body holding member 51, and approaches the dielectric 63. In addition, when the writing pressure applied to the core body 4 is released, the first electrode 61 acts to push back the transmission member 5 and the core body 4, returning the transmission member 5 and the core body 4 to their original positions.

In this way, the pressure (pen pressure) applied to the core body 4 can be detected in real time according to the capacitance between the first electrode 61 and the second electrode 64, which changes as the first electrode 61 approaches or moves away from the dielectric 63. The first electrode 61 of the pressure detection unit 6 is in contact with a pressure detection unit coil spring 65 made of a conductive material such as metal. In this case, an extension line (conductive wire) 65L from the pressure detection unit coil spring 65 and an extension line (conductive wire) 64L from the second electrode are connected to the capacitance detection circuit 8d of the printed circuit board 8. This allows the pressure (pen pressure) applied to the core body 4 to be detected based on the capacitance between the first electrode 61 and the second electrode 64 of the pressure detection unit 6.

The main parts for realizing the electronic pen function provided on the front cap 22 side are stored in the inner space formed by connecting the transmitting/receiving electrode 13, the pipe-shaped holding members 7a and 7b, and the cup-shaped pressure detection unit holding member 66. That is, as shown in FIG. 2, the transmission member 5, the pressure detection unit 6, the core coil spring 41C, and the pressure detection unit coil spring 65 are stored in the inner space formed by the transmitting/receiving electrode 13, the pipe-shaped holding members 7a and 7b, and the cup-shaped pressure detection unit holding member 66.

The transmitting/receiving electrode 13 is formed in a pipe shape from a conductive material such as metal, and has a tapered shape on the pen tip side. As shown in FIG. 2, the tip surface of the transmitting/receiving electrode 13 on the pen tip side abuts against the inner tip surface of the front cap 22, and a certain range of the outer side surface of the transmitting/receiving electrode 13 from the pen tip side toward the rear end side is made to contact the inner wall surface of the front cap 22. This prevents the transmitting/receiving electrode 13 from rattling in a direction intersecting with the axial direction. In addition, the inner diameter of the portion of the transmitting/receiving electrode 13 facing the core body 4 on the pen tip side is short and thick, and the inner diameter of the portion of the transmitting/receiving electrode 13 facing the holding portion 51a of the transmission member 5 on the rear end side is long and thin.

Pipe-shaped holding members 7a and 7b made of, for example, hard resin are provided at the rear of the transmitting/receiving electrode 13. The tip surface of the pipe-shaped holding member 7a located on the pen tip side abuts against the rear end surface of the transmitting/receiving electrode 13 as shown in FIG. 2. The rear end portion of the pipe-shaped holding member 7a located on the pen tip side is fitted and connected to the tip portion of the pipe-shaped holding member 7b located on the rear end side as shown in FIG. 2. Furthermore, as shown in FIG. 2, the rear end portion of the pipe-shaped holding member 7b located on the rear end side fits inside the pressure detection unit holding member 66 to hold the pressing member 52.

The pressing head 52a of the pressing member 52 protrudes from the rear end opening of the pipe-shaped holding member 7b. The diameter of the pressing head 52a of the pressing member 52 is longer than the diameter of the rear end opening of the pipe-shaped holding member 7b, and the pressing head 52a is not located inside the pipe-shaped holding member 7b. As shown in FIG. 2, the pressure detection coil spring 65 described above, which is made of a conductive material, is provided between the pipe-shaped holding member 7b and the first electrode 61 of the pressure detection unit 6. The extension wire (conductive wire) 65L of the pressure detection coil spring 65 is connected to the capacitance detection circuit 8d of the printed circuit board 8 as an extension wire from the first electrode as described above. The extension wire 64L from the second electrode of the pressure detection unit 6 is also connected to the capacitance detection circuit 8d of the printed circuit board 8.

Furthermore, as shown in FIG. 2, a pressure detection unit holding member 66 formed in a cup shape from, for example, hard resin is placed over the pressure detection unit 6, and as described above, the narrowed portion at the rear end of the pipe-shaped holding member 7b fits into it. That is, the outer diameter of the narrowed portion at the rear end of the pipe-shaped holding member 7b is slightly shorter than the inner diameter of the recess of the pressure detection unit holding member 66, so that the rear end of the pipe-shaped holding member 7b fits into the cup-shaped pressure detection unit holding member 66. When the pressure detection unit holding member 66 is fitted into the rear end of the pipe-shaped holding member 7b and pushed in, the tip surface of the pressure detection unit holding member 66 abuts against the rear end surface of the thickened portion of the pipe-shaped holding member 7b.

In this state, the pressure detection unit 6 is fixed to the inner bottom surface part on the rear end side of the pressure detection unit holding member 66. At the same time, the pressure detection unit coil spring 65 sandwiched between the pipe-shaped holding member 7b and the pressure detection unit 6 moderately presses the first electrode against the dielectric 63 side via the ring-shaped spacer 62, so as to hold the first electrode 61 in an appropriate position. In this state, the apex part of the pressing head 52a of the pressing member 52 is in slight contact with the first electrode 61. Therefore, in response to the pressure applied to the core body 4, the pressing member 52 instantly presses the first electrode 61 of the pressure detection unit 6, making it possible to detect the pressure (writing pressure). The pressure detection unit holding member 66 is fixed so that it does not move, with the substrate holder 3 pressed against it from the rear end side.

2, a coil spring 13C for the transmitting/receiving electrode is provided on the side of the pipe-shaped holding member 7a. One end of the coil spring 13C is connected to the transmitting/receiving electrode 13. The other end of the coil spring 13C is formed by the end of the extension wire (conductor wire) 13L extended from the coil spring 13C in FIG. 2, and is connected to the transmitting circuit 8s provided on the printed circuit board 8. In this way, the components consisting of the core body 4, the transmission member 5, the pressure detection unit 6, the core body coil spring 41C, the transmitting/receiving electrode 13, and the coil spring 13C for the transmitting/receiving electrode are held in the housing 2 by the pen tip side holding parts 3a and 3b of the board holder 3. In the electronic pen 1 of the first embodiment, the parts that constitute the electronic pen function described above are stored in the inner housing 2in, making it easy to install it in the housing 2.

In this way, the transmitting/receiving electrode 13, the pipe-shaped holding member 7, and the pressure detection unit holding member 66 are fixed in a connected state to the front cap 22 side, sandwiched between the inner tip surface of the front cap 22 and the substrate holder 3. In the internal space formed by connecting the transmitting/receiving electrode 13, the pipe-shaped holding member 7, and the pressure detection unit holding member 66, the transmission member 5 and the pressure detection unit 6 are provided as described above with reference to FIG. 2, and the core body 4 is detachable from the core body holding member 51.

In this case, as shown in FIG. 2, a relatively large space (clearance) is provided around the core holding member 51 to which the core 4 is attached. This allows the core holding member 51 to slide in and out of the axial direction without stress when pressure (writing pressure) is applied to the core 4. However, because the core 4 slides in the axial direction in response to the writing pressure applied, a small gap is created between the opening of the front cap 22 and the side of the core 4.

Moisture may get in through this gap and reach the coil spring 41C for the core, the pressure detection unit 6, and even the printed circuit board 8 from the space around the core holding member 51 to which the core 4 is attached. In addition, moisture that gets in through the gap between the opening of the front cap 22 and the side of the core 4 may reach the coil spring 13C in the subsequent stage, the pressure detection unit 6, and even the printed circuit board 8 through the gap between the transmitting/receiving electrode 13 and the inner wall surface of the front cap 22.

If the coil springs 41C, 13C, pressure detection unit 6, or printed circuit board 8 that transmit signals become wet, problems such as changes in electrical characteristics and partial shorting of the electronic circuitry, causing the electronic pen to no longer function, can occur. Therefore, in the electronic pen 1 of the first embodiment, as shown in FIG. 2, a first ring-shaped elastic member 16 is attached to the rear end side of the transmitting/receiving electrode 13. The first ring-shaped elastic member 16 has an inner wall surface that is in close contact with the entire circumference of the rear end side of the transmitting/receiving electrode 13, and an outer wall surface that is in close contact with the inner wall surface of the front cap 22 over the entire circumference.

2, when the first ring-shaped elastic member 16 is cut in two in the axial direction through the center of the opening of the first ring-shaped elastic member 16, the side (outer wall surface) that comes into close contact with the inner wall surface of the front cap 22 is arc-shaped. This shape makes it easy to install the transmitting/receiving electrode 13 to which the first ring-shaped elastic member 16 is attached into the front cap 22, and can increase the adhesion between the inner wall surface of the first ring-shaped elastic member 16 and the inner wall surface of the front cap 22. In this way, the first ring-shaped elastic member 16 realizes the function of sealing the gap that occurs between the side of the transmitting/receiving electrode 13 and the inner wall surface of the front cap 22. This prevents moisture that has entered through the opening of the front cap 22 from entering the pressure detection unit 6 or the printed circuit board 8 through the gap between the transmitting/receiving electrode 13 and the inner wall surface of the front cap 22.

Furthermore, as shown in FIG. 2, a second ring-shaped elastic member 17 is provided that is in close contact with the entire circumference of the side surface slightly toward the rear end of the holding portion 51a of the core body holding member 51 of the transmission member 5 and the entire circumference of the inner wall surface of the rear end side of the transmission/reception electrode 13. As shown in FIG. 2, the second ring-shaped elastic member 17 has a small opening on the pen tip side and a large opening on the rear end side, so that the side surface is inclined. In other words, the second ring-shaped elastic member 17 is shaped like a dish with a missing bottom. In this case, the inner edge side of the opening on the pen tip side is in close contact with the entire circumference of the side surface of the holding portion 51a of the core body holding member 51, and the outer edge side of the opening on the rear end side is in close contact with the entire circumference of the inner wall surface on the rear end side of the transmission/reception electrode 13. This prevents moisture that has entered through the opening of the front cap 22 from entering the pressure detection unit 6 or the printed circuit board 8 through the space between the core body 4 and the transmission member 5 and the transmission/reception electrode 13.

Figure 3 is an enlarged cross-sectional view of the location where the second ring-shaped elastic member 17 is installed in the electronic pen 1 of the first embodiment. As shown in Figure 3, the inner edge of the opening on the pen tip side of the second ring-shaped elastic member 17 fits into a recess provided on the side of the holding portion 51a of the core holding member 51, and is in close contact with the entire circumference of the side of the holding portion 51a. Meanwhile, the outer edge of the opening on the rear end side of the second ring-shaped elastic member 17 fits into a recess on the rear end side of the transmitting/receiving electrode 13, and is pressed down from the rear end side by the tip surface of the pipe-shaped holding member 7a, so that it is in close contact with the entire circumference of the inner wall surface on the rear end side of the transmitting/receiving electrode 13.

The inner edge of the opening on the pen tip side of the second ring-shaped elastic member 17 is machined to be spherical, and similarly, the outer edge of the opening on the rear end side of the second ring-shaped elastic member 17 is also machined to be spherical. In this way, the second ring-shaped elastic member 17 has a different shape from the first ring-shaped elastic member 16. The second ring-shaped elastic member 17 is in close contact with the holding portion 51a of the core body holding member 51 of the transmission member 5 in which the core body 4 is held. For this reason, the second ring-shaped elastic member 17 needs to deform as the core body 4 and the transmission member 5 slide in the axial direction in response to the writing pressure applied to the core body 4, and therefore has a shape with inclined sides to facilitate deformation.

The inner edge of the opening on the pen tip side of the second ring-shaped elastic member 17 and the outer edge of the opening on the rear end side are machined into a spherical shape so as not to impede the deformation of the second ring-shaped elastic member 17 that accompanies the axial movement of the core body 4 and the transmission member 5. As shown in Figure 3, when the core rod 41 is pushed in the direction indicated by the arrow PS by applying writing pressure to the core body 4, the inner edge of the opening on the pen tip side of the second ring-shaped elastic member 17 is pushed toward the rear end side, causing it to deform.

In this case, the inner edge of the opening on the pen tip side of the second ring-shaped elastic member 17 rotates slightly as shown by the arrow a in FIG. 3. Also, the outer edge of the opening on the rear end side of the second ring-shaped elastic member 17 rotates slightly as shown by the arrow b in FIG. 3. This makes it possible to avoid impeding the deformation of the second ring-shaped elastic member 17 that accompanies the movement of the core body 4 and the transmission member 5 in the axial direction. In other words, the shape of the second ring-shaped elastic member 17 is designed to allow the core body 4 and the transmission member 5 to slide appropriately in the axial direction according to the applied writing pressure.

Figure 4 is a diagram showing an equivalent circuit of the electronic pen 1 of the first embodiment described with reference to Figures 1 to 3. As shown in Figure 4, the core rod 41 of the core body 4 is connected to the transmitting circuit 8s through the core body coil spring 41C, and is capable of transmitting a position indication signal with a frequency of, for example, f0. In addition, the transmitting/receiving electrode 13 is connected to a switch circuit SW through a coil spring 13C, and is connected to the transmitting circuit 8s and the demodulation circuit 8r through this switch circuit SW. The switch circuit SW is switched and controlled by the control IC 10.

Therefore, when the switch circuit SW is switched to the transmitting circuit 8s side, the transmitting/receiving electrode 13 can send out a tilt detection signal with a frequency of, for example, f1 from the transmitting circuit 8s. Also, when the switch circuit SW is switched to the demodulation circuit 8r side, the signal from the position detection device received through the transmitting/receiving electrode 13 can be supplied to the demodulation circuit 8r. This makes it possible to receive a request to send identification information from the position detection circuit side through the transmitting/receiving electrode 13, demodulate this with the demodulation circuit 8r, and notify the control IC 10 of the demodulation result. In this case, the control IC 10 can control the transmitting circuit 8s and send a position indication signal including the identification ID of the device to the position detection device. In this way, the transmitting/receiving electrode 13 makes it possible to transmit a tilt detection signal and receive an identification signal from the position detection circuit side.

The first electrode 61 of the pressure detection unit 6, which is pressed by the transmission member 5 in response to the writing pressure applied to the core 4, is connected to a capacitance detection circuit 8d via a pressure detection coil spring 65, and the second electrode 64 of the pressure detection unit 6 is connected to the capacitance detection circuit 8d via an extension wire 64L of the second electrode. This allows the detection circuit 8d to detect the pressure (writing pressure) applied to the core 4 in response to changes in capacitance.

The pressure (writing pressure) applied to the core body 4 detected by the detection circuit 8d is included in a position indication signal in the transmission circuit 8s so that it can be transmitted from the core body 4 to the position detection sensor. The transmission circuit 8s is controlled by a control IC 10, and driving power is supplied to each circuit section by a power supply circuit 15. Note that in the electronic pen 1 of this embodiment, the core body coil spring 41C, the coil spring 13C, and the pressure detection section coil spring 65 do not function as inductor elements.

In other words, the core coil spring 41C realizes the function of holding the core holding member 51 in the housing 2 in a state in which it can move freely without being biased, and the function of supplying a position indication signal from the transmitting circuit 8s to the core rod 41 of the core 4. In addition, the coil spring 13C realizes the function of supplying the tilt detection signal from the transmitting circuit 8s to the transmitting/receiving electrode 13 smoothly and without affecting the surrounding area.

The coil spring 13C also functions to supply the signal received through the transmitting/receiving electrode 13 to the demodulation circuit 8r without affecting the surroundings and without forcing it to do so. The pressure detection coil spring 65 biases the first electrode 61 of the pressure detection unit 6 toward the dielectric 63 with an appropriate force, enabling it to be positioned at an appropriate position, and also functions to connect the first electrode 61 to the capacitance detection circuit 8d.

<Effects of the Electronic Pen 1 of the First Embodiment>
1 to 4, the electronic pen 1 of the first embodiment described with reference to Fig. 1 to 4 prevents moisture from entering through the opening of the front cap 22 from entering into the rear stage by the function of the first ring-shaped elastic member 16 and the second ring-shaped elastic member 17. Therefore, moisture entering through the opening of the front cap 22 does not reach the electronic components located in the rear stage of the first and second ring-shaped elastic members 16 and 17, and does not cause changes in electrical characteristics or failures due to moisture intrusion. Of course, fine dust and the like entering through the opening of the front cap 22 does not reach the electronic components, and performance degradation or failures caused by the adhesion of fine dust and the like do not occur.

<Another Example of Electronic Pen 1 of First Embodiment>
In the case of the electronic pen 1 of the first embodiment, as shown in Fig. 2, moisture that has infiltrated from the opening of the front cap 22 may remain in the stage before the first and second ring-shaped elastic members 16 and 17. In the electronic pen 1 configured as shown in Fig. 2, it is assumed that moisture that has infiltrated from the opening of the front cap 22 has been retained in the space between the core body 4 and the transmission member 5 in the stage before the second ring-shaped elastic member 17 and the transmitting/receiving electrode 13. In this case, the conductive core rod 41 of the core body 4 is provided in the holding portion 51a and is held by the elastic member 51c whose side surface is exposed from the side surface of the holding portion 51a. Therefore, the core rod 41 and the elastic member 51c are electrically connected to the transmitting/receiving electrode 13 through the infiltrated moisture, and the electronic pen 1 does not function as an electronic pen.

In other words, the position indication signal cannot be sent properly through the core rod 41 of the core body 4, and the tilt detection signal cannot be sent properly from the transmitting/receiving electrode 13, so the electronic pen will no longer function. Of course, the electronic components located downstream of the first and second ring-shaped elastic members 16 and 17 are not affected by moisture. For this reason, if the moisture remaining in the space between the core rod 41 and the elastic member 51c and the transmitting/receiving electrode 13 is removed by evaporation or the like, the electronic pen 1 will regain its function as an electronic pen. However, as long as moisture remains and the core rod 41 and the elastic member 51c are conductive to the transmitting/receiving electrode 13, the electronic pen will no longer function as an electronic pen.

Therefore, in electronic pen 1A, which is another example of electronic pen 1 of the first embodiment, a second ring-shaped elastic member 17A is provided at a position closer to the pen tip side. This prevents moisture that has entered through the opening of front cap 22 from penetrating and remaining in the space between core rod 41 and elastic member 51c and transmitting/receiving electrode 13. Below, we will specifically explain electronic pen 1A, which is another example of electronic pen 1 of the first embodiment.

Figure 5 is a diagram for explaining the main parts of the pen tip side of electronic pen 1A, which is another example of electronic pen 1 of the first embodiment. In electronic pen 1A shown in Figure 5, parts configured similarly to electronic pen 1 shown in Figure 2 are given the same reference numerals, and detailed explanations of these parts will be omitted to avoid duplication. In electronic pen 1A shown in Figure 5, second ring-shaped elastic member 17A is provided closer to the pen tip side than second ring-shaped elastic member 17 of electronic pen 1 shown in Figure 2.

In this example of the electronic pen 1A, the second ring-shaped elastic member 17A is formed in the same manner as the second ring-shaped elastic member 17 of the electronic pen 1 of the first embodiment described above. That is, the second ring-shaped elastic member 17A has a small opening on the pen tip side and a large opening on the rear end side, so that the side is inclined and the shape is like a dish with a missing bottom (bottom surface). In the electronic pen 1A, the inner edge side of the opening on the pen tip side of the second ring-shaped elastic member 17A is in close contact with both the rear end of the protective member 42 of the core body 4 and the side of the core rod 41 over the entire circumference. In addition, the outer edge side of the opening on the rear end side of the second ring-shaped elastic member 17A is in close contact with the inner wall surface of the central part in the axial direction of the transmitting/receiving electrode 13A over the entire circumference.

For this reason, the transmitting/receiving electrode 13A has a step in the center in the axial direction with which the outer edge of the opening on the rear end side of the second ring-shaped elastic member 17A engages. Furthermore, compared to the pipe-shaped holding part 7a in FIG. 2, the pipe-shaped holding member 7aA located at the rear of the transmitting/receiving electrode 13A is extended toward the pen tip side so as to fit into the transmitting/receiving electrode 13A from the rear end side. As a result, the outer edge of the opening on the rear end side of the ring-shaped elastic member 17A is surrounded by the inner wall surface of the transmitting/receiving electrode 13A and the tip surface of the pipe-shaped holding member 7aA, and is held so as not to move in the axial direction.

As a result, moisture that has entered through the opening of the front cap 22 is prevented from entering the rear end side by the second ring-shaped elastic member 17A. Therefore, moisture that has entered through the opening of the front cap 22 can be prevented from entering the space where the core rod 41 and elastic member 51c face the transmitting/receiving electrode 13A. This prevents the core rod 41 and elastic member 51c of the core body 4 from becoming conductive with the transmitting/receiving electrode 13A through the moisture that has entered, and prevents the electronic pen 1A itself from failing to function as an electronic pen due to the intrusion of moisture. Of course, in the case of the electronic pen 1A, the first and second ring-shaped elastic members 16 and 17A can prevent moisture, dust, etc. from entering the mounting area of the subsequent electronic components (including circuit components), so there is no change or abnormality in the electrical characteristics.

[Second embodiment]
In the case of the electronic pen 1A described with reference to Fig. 5, moisture that penetrates through the opening of the front cap 22 does not reach the mounting locations of various electronic components in the subsequent stages. Furthermore, there is no electrical conduction between the core rod 41 and the elastic member 51c and the transmitting/receiving electrode 13A through the medium of moisture that has penetrated. However, the second ring-shaped elastic member 17A of the electronic pen 1A shown in Fig. 5 is located closer to the pen tip than the second ring-shaped elastic member 17 of the electronic pen 1 shown in Fig. 2, so that the load applied to the core body 4 that can be detected as writing pressure, that is, the so-called on-load, becomes heavier.

Therefore, when using the electronic pen 1A shown in FIG. 5, writing is not possible without applying a stronger writing pressure than when using the electronic pen 1 shown in FIG. 2, and it is thought that there will be a demand for a lighter on-load. In addition, in the case of the electronic pen 1A shown in FIG. 5, when the core body 4 is removed, moisture that penetrates through the opening of the front cap 22 reaches the mounting locations of various electronic components in the subsequent stage. In addition, in this case, if the core body 4 is attached while the infiltrated moisture is accumulating, it will cause electrical conduction between the core rod 41 and the elastic member 51c and the transmitting/receiving electrode 13A. The electronic pen 1B of the second embodiment described below is designed to prevent these inconveniences from occurring.

Figure 6 is a diagram for explaining the main parts of the pen tip side of electronic pen 1B of the second embodiment. The basic configuration of electronic pen 1B shown in Figure 6 is configured similarly to electronic pen 1 of the first embodiment described using Figures 1 to 4. However, there are some parts in which electronic pen 1B of the second embodiment and electronic pen 1 of the first embodiment are slightly different, for example, due to a simplified configuration or enhanced waterproof function. For this reason, in electronic pen 1B of the second embodiment shown in Figure 6, the same reference numerals are used for parts configured similarly to electronic pen 1 of the first embodiment shown in Figure 2, and detailed descriptions of these parts will be omitted to avoid duplication, and the following description will focus on the parts that differ in configuration.

<Ground electrode 14, pipe-shaped holding member 7>
The electronic pen 1B of the second embodiment is provided with a ground electrode (ground ring) 14 on the rear end side of the front cap 22. The case body 21 made of a conductive material is configured to be electrically connected to the earth conductor of the printed circuit board 8 via the ground electrode 14. This allows the case body 21 to be easily and reliably connected to the earth conductor of the printed circuit board 8. In addition, in the electronic pen 1 of the first embodiment, the pipe-shaped holding members 7a and 7b mainly hold the transmission member 5 to ensure a movement area in the axial direction. In contrast, in the electronic pen 1B of the second embodiment, a pipe-shaped holding member 7 formed integrally with the pipe-shaped holding members 7a and 7b is used, simplifying the configuration.

<Transmission member 5A>
6, the transmission member 5A of the electronic pen 1B of the second embodiment is composed of two separate members, a core body holding member 51A located on the pen tip side and a pressing member 52 located behind the core body holding member 51A. The pressing member 52 is similar to the pressing member 52 of the electronic pen 1 of the first embodiment and is made of a non-conductive material such as a hard resin. In contrast, the core body holding member 51A has a cup-shaped holding portion 51x with a recess, and an extension portion 51y that has a fitting recess into which the rear end side of the holding portion 51x fits and that extends in the opposite direction to the pen tip.

In the electronic pen 1B of the second embodiment, at least the holding portion 51x of the core body holding member 51A is formed of a conductive material, such as a conductive resin or metal, and the extension portion 51y is formed of a non-conductive material, such as a hard resin. The extension portion 51y may also be formed of a conductive material. In the electronic pen 1 of the first embodiment, a ring-shaped elastic member 51c having conductivity, such as conductive rubber, is fixed to the inner wall surface of the holding portion 51a of the transmission member 5. As a result, the core rod 41 of the core body 4 is fixed to the holding portion 51a by the elastic member 51c and is connected to the core body coil spring 41C via the elastic member 51c to receive the supply of a position indication signal.

However, in the electronic pen 1B of the second embodiment, the holding portion 51x of the transmission member 5A itself is made of a conductive material, and the core rod 41 of the core body 4 is directly fitted into and held in the recess of the holding portion 51x. The core body coil spring 41C is connected to the holding portion 51x, and a position indication signal from the transmission circuit 8s is supplied from the core body coil spring 41C to the core rod 41 via the holding portion 51x. The components consisting of the core body 4, pressure detection unit 6, core body coil spring 41C, transmitting/receiving electrode 13, and coil spring 13C for the transmitting/receiving electrode are configured in the same manner as the electronic pen 1 of the first embodiment described above.

In this way, the electronic pen 1B of the second embodiment includes, on the pen tip side, the core body 4, the transmission member 5A, the pressure detection unit 6, the pipe-shaped holding member 7, the coil spring 41C for the core body, the transmitting/receiving electrode 13, the coil spring 13C for the transmitting/receiving electrode, and the coil spring 65 for the pressure detection unit. These components on the pen tip side are held within the housing 2 by the pen tip side holding parts 3a and 3b of the board holder 3.

In the electronic pen 1 of the first embodiment, the part that constitutes the electronic pen function is housed in the inner housing 2in and is attached to the housing 2. However, in the case of the electronic pen 1B of the second embodiment, the inner housing 2in does not exist, and the electronic pen 1B is configured to include a ground electrode 14. It is also possible to configure the core body holding portion 51 of the transmission member 5 of the electronic pen 1 shown in FIG. 2 and the electronic pen 1B shown in FIG. 5 in the same manner as the core body holding portion 51A of the electronic pen 1B shown in FIG. 6.

Furthermore, as shown in FIG. 6, the electronic pen 1B of the second embodiment includes first and second ring-shaped elastic members 16 and 17, similar to the electronic pen 1 of the first embodiment shown in FIG. 2. As shown in FIG. 6, the inner wall surface of the first ring-shaped elastic member 16 is in close contact with the entire circumference of the side surface of the rear end side of the transmitting/receiving electrode 13, and the outer wall surface is in close contact with the entire circumference of the inner wall surface of the front cap 22. As shown in FIG. 6, when the first ring-shaped elastic member 16 is cut in two in the axial direction through the center of the opening of the first ring-shaped elastic member 16, the side surface (outer wall surface) that is in close contact with the inner wall surface of the front cap 22 has an arc shape.

This shape makes it easy to install the transmitting/receiving electrode 13 with the first ring-shaped elastic member 16 attached inside the front cap 22, and also improves the adhesion between the inner wall surface of the first ring-shaped elastic member 16 and the inner wall surface of the front cap 22. In this way, the first ring-shaped elastic member 16 achieves the function of sealing the gap that occurs between the side surface of the transmitting/receiving electrode 13 and the inner wall surface of the front cap 22. This prevents moisture that has entered through the opening of the front cap 22 from entering the pressure detection unit 6 or the printed circuit board 8 through the gap between the transmitting/receiving electrode 13 and the inner wall surface of the front cap 22.

Furthermore, as shown in FIG. 6, a second ring-shaped elastic member 17 is provided that is in close contact with the entire circumference of the side surface of the central portion in the axial direction of the holding portion 51x of the core body holding member 51A of the transmission member 5A and the entire circumference of the inner wall surface on the rear end side of the transmission/reception electrode 13. As shown in FIG. 6, the second ring-shaped elastic member 17 has a small opening on the pen tip side and a large opening on the rear end side, so that the side surface is inclined. In other words, the second ring-shaped elastic member 17 is shaped like a dish with a missing bottom. In this case, the inner edge side of the opening on the pen tip side is in close contact with the entire circumference of the side surface of the holding portion 51x of the core body holding member 51A, and the outer edge side of the opening on the rear end side is in close contact with the entire circumference of the inner wall surface on the rear end side of the transmission/reception electrode 13. This prevents moisture that has entered through the opening of the front cap 22 from entering the pressure detection unit 6 or the printed circuit board 8 through the space between the core body 4 and the transmission member 5A and the transmission/reception electrode 13.

The second ring-shaped elastic member 17 of the electronic pen 1B of the second embodiment is configured in the same manner as the second ring-shaped elastic member 17 of the electronic pen 1 of the first embodiment described with reference to FIG. 3. For this reason, the shape of the second ring-shaped elastic member 17 is designed so that the core body 4 and the transmission member 5 can slide appropriately in the axial direction according to the applied writing pressure. This makes it possible to not impede the deformation of the second ring-shaped elastic member 17 that accompanies the movement of the core body 4 and the transmission member 5 in the axial direction. In other words, it is possible to push the core body 4 in the axial direction with a light load without increasing the on-load.

In this way, in the electronic pen 1B of the second embodiment, like the electronic pen 1 of the first embodiment, the first and second ring-shaped elastic members 16, 17 function to prevent moisture that has entered through the opening of the front cap 22 from entering the pressure detection unit 6 or the printed circuit board 8. However, at least the holding portion 51x of the transmission member 5A is made of a conductive material. Therefore, if moisture that has entered through the opening of the front cap 22 remains between the core body 4 and the transmission member 5A and the transmitting/receiving electrode 13, the core rod 41 and the holding portion 51x will become conductive to the transmitting/receiving electrode 13 through the moisture, and the electronic pen will no longer function.

Therefore, in the electronic pen 1B of this second embodiment, as shown in FIG. 6, a cylindrical insulating member 18 is provided. At the rear end side, the rear end surface of the insulating member 18 adheres closely to the inner edge portion of the second ring-shaped elastic member 17, and at the pen tip side, the rear end portion of the protective member 42 of the core body 4 fits into and adheres closely to the tip portion, covering the side of the holding portion 51x so that it is not exposed. In the second embodiment, the insulating member 18 is an elastic member formed of a non-conductive material such as elastomer (so-called synthetic rubber), and as described above, adheres closely to the inner edge portion of the second ring-shaped elastic member 17, the rear end portion of the protective member of the core body 4, and the side portion of the holding portion 51x.

By providing such a cylindrical insulating member 18, in the electronic pen 1B of the second embodiment, moisture that has entered through the opening of the front cap 22 is prevented from coming into contact with the core rod 41 of the core body 4 and the holding portion 51x of the transmission member 5A. Furthermore, if moisture enters through the opening of the front cap 22 when the core body 4 is not attached to the housing 2, the entered moisture can be discharged from the entry path. Furthermore, suppose that moisture enters through the opening of the front cap 22 when the core body 4 is not attached to the housing 2. Even in this case, if the core body is attached, the core rod 41 of the core body 4 and the holding portion 51x of the transmission member 5A are reliably insulated from the transmitting/receiving electrode 13, so that the core rod 41 and the holding portion 51x of the transmission member 5A are not electrically connected to the transmitting/receiving electrode 13.

<Effects of the electronic pen 1B according to the second embodiment>
As described above, the electronic pen 1B of the second embodiment can realize a light on-load similar to that of the electronic pen 1 shown in FIG. 2, without moisture penetrating through the opening of the front cap 22 reaching the mounting locations of various electronic components in the subsequent stage. Furthermore, the electronic pen 1B does not conduct the core rod 41 and the elastic member 51c with the transmitting/receiving electrode 13 through the medium of moisture penetrating through the opening of the front cap 22. Even when the core body 4 is removed, moisture penetrating through the opening of the front cap 22 does not reach the mounting locations of various electronic components in the subsequent stage. In this case, even if the core body 4 is attached in a state where the invaded moisture is retained, the core rod 41 and the elastic member 51c do not conduct with the transmitting/receiving electrode 13A. Of course, in the case of the electronic pen 1B, the first and second ring-shaped elastic members 16 and 17 can prevent moisture, dust, etc. from entering the mounting area of the electronic components in the subsequent stage, so there is no change or interference in the electrical characteristics.

<Another Example of Electronic Pen 1B of Second Embodiment>
Fig. 7 is a diagram for explaining the main part of the pen tip side of an electronic pen 1C which is another example of the electronic pen 1B of the second embodiment. In the electronic pen 1C shown in Fig. 7, the same reference numerals are given to the parts configured similarly to the electronic pen 1B shown in Fig. 6, and detailed explanations of these parts are omitted to avoid duplication. In the electronic pen 1C shown in Fig. 7, the transmission member 5B is composed of a core body holding part 51B and a pressing member 52, but the configuration of the core body holding member 51B is different from that of the core body holding member 51A of the electronic pen 1B shown in Fig. 6.

The core body holding member 51A of the electronic pen 1B shown in FIG. 6 is composed of two members, a holding portion 51x and an extension portion 51y. In contrast, the core body holding member 51B of the electronic pen 1C shown in FIG. 7 is formed as a single unit from a conductive material. That is, as shown in FIG. 7, the core body holding member 51B of the electronic pen 1C not only holds the core body 4, but also functions as a holding portion that electrically connects the core body 4 to the downstream transmission circuit 8s through the core body coil spring 41C. The core body holding member 51B of the electronic pen 1C also functions as a pressing portion that transmits the writing pressure applied to the core body 4 to the pressing member 52.

In this way, the core body holding member 51B of the electronic pen 1C is an integrated part that combines two functions. This reduces the number of parts from the core body 4 to the pressure detection unit 6, and allows the function of the electronic pen to be realized. It is also possible, of course, to configure the core body holding part 51 of the transmission member 5 of the electronic pen 1 shown in FIG. 2 and the electronic pen 1B shown in FIG. 5 in the same manner as the core body holding part 51B of the electronic pen 1C shown in FIG. 7.

In this way, the entire core holding member 51B is integrally formed from a conductive material. However, the first and second ring-shaped elastic members 16, 17 and the insulating member 18 prevent the core holding member 51B itself from coming into contact with moisture that has infiltrated. Therefore, in the case of the electronic pen 1C of this example, it is possible to prevent the core rod 41 and the core holding member 51B from becoming electrically conductive with the transmitting and receiving electrodes 13 through moisture. Therefore, in the case of the electronic pen 1C of this example, as in the case of the electronic pen 1B shown in Figure 6, the electronic pen will not lose its function as an electronic pen even if moisture infiltrates through the opening in the front cap 22. This makes it possible to realize a highly reliable electronic pen.

[Modification]
The electronic pens 1, 1A, 1B, and 1C of the first and second embodiments described above are all capacitive electronic pens, and are provided with a conductive core rod 41 and transmitting/receiving electrodes 13 and 13A in order to detect tilt and receive information (signals) from the position detection device. The core rod 41 of the core body 4 is located on the axis when attached to the electronic pens 1, 1A, 1B, and 1C, and is therefore sometimes called a central conductor. The transmitting/receiving electrodes 13 and 13A are also called peripheral electrodes, as they are penetrated by the core body 4 and are located so as to surround the periphery of the core rod 41. In addition, in the case of an electronic pen that does not receive information (signals) from the position detection device, the transmitting/receiving electrodes 13 and 13A are electrodes dedicated to transmitting tilt detection signals.

As described above, the electronic pens 1, 1A, 1B, and 1C of the first and second embodiments described above are equipped with a core rod 41 (center electrode) and transmitting/receiving electrodes 13 and 13A (peripheral electrodes). However, this is not limited to this. In the case of an electronic pen that does not need to detect the inclination of the electronic pen or receive information (signals) from a position detection device, there is no need to provide the transmitting/receiving electrodes 13 and 13A. In this case, a cylindrical internal component made of a non-conductive material can be formed and used in place of the transmitting/receiving electrodes 13 and 13A.

In addition, when the transmitting/receiving electrodes 13, 13A or cylindrical internal components are not used, it is also possible to provide a single ring-shaped elastic member that adheres to the entire circumference of the side of the core body holding portion 51, 51A, 51B and the entire circumference of the inner wall surface of the housing. In this case, the ring-shaped elastic member has a small opening on the pen tip side and a large opening on the rear end side, so that the side is inclined, the inner edge of the opening on the pen tip side adheres to the entire circumference of the side of the core body holding portion, and the outer edge of the opening on the rear end side adheres to the entire circumference of the inner wall surface of the housing. In other words, the ring-shaped elastic member has a shape similar to that of the second ring-shaped elastic member 17 described using Figures 2 and 3, although the size is different. This makes it possible to keep the on-load as small as possible.

This invention can be applied not only to capacitive electronic pens, but also to, for example, electromagnetic induction electronic pens. In this case, a cylindrical internal component made of a non-conductive material may be used instead of the transmitting and receiving electrodes 13, 13A. In the case of an electromagnetic induction electronic pen, a core rod made of, for example, resin is provided so as to penetrate the cylindrical ferrite core, a coil is wound around the ferrite core, and a capacitor is connected to the coil to form a resonant circuit. In this case, a cylindrical insulating member may be provided to insulate the coil wound around the ferrite core from moisture. By arranging the insulating member between the ferrite core and the inside of the pen housing, moisture will not penetrate into the coil wound around the ferrite core. The insulating member corresponds to the insulating member 18 of the electronic pens 1B, 1C of the second embodiment described above.

The first and second ring-shaped elastic members 16, 17, and 17A described above can be formed, for example, using an elastomer material. Of course, they are not limited to elastomer materials, and the first and second ring-shaped elastic members 16, 17, and 17A can be formed from various elastic materials such as natural rubber and water-repellent Poron (registered trademark). The insulating member 18 can also be made of various insulating materials with water resistance, such as elastomers and natural rubber.

As another example, the second ring-shaped elastic member 17 and the insulating member 18 may be integrated. By integrating them, it is possible to reduce the number of parts and prevent moisture from entering through the gap between the second ring-shaped elastic member 17 and the insulating member 18. One method for molding them as an integrated unit is by double molding (two-color molding). Comparing the softness of the second ring-shaped elastic member 17 and the insulating member 18, the second ring-shaped elastic member 17 is softer.

[others]
As can be seen from the above description of the embodiment, the housing in the claims corresponds to the part consisting of the case body 21, the front cap 22, and the rear cap 23 in the embodiment, and mainly corresponds to the front cap 22. The core body holding part in the claims mainly corresponds to the core body holding members 51, 51A, and 51B in the embodiment. The electronic components in the claims correspond to various electronic components mounted to realize the functions of the electronic pen, such as the pressure detection unit 6 and the printed circuit board 8. The cylindrical internal components in the claims mainly correspond to the transmitting and receiving electrodes 13 and 13A, and may be cylindrical internal components that are not conductive.

The first ring-shaped elastic member in the claim corresponds to the first ring-shaped elastic member 16 in the embodiment, and the second ring-shaped elastic member in the claim corresponds to the second ring-shaped elastic member 17 in the embodiment. The pen pressure detection unit in the claim corresponds to the pressure detection unit 6 in the embodiment. The first and second transmission circuits in the claim correspond to the transmission circuit 8s in the embodiment. The insulating member in the claim corresponds to the insulating member 18 in the embodiment. The outer ring-shaped elastic member in the claim corresponds to the first ring-shaped elastic member 16 in the embodiment, and the inner ring-shaped elastic member in the claim corresponds to the second ring-shaped elastic member 17A in the embodiment.

1, 1A, 1B, 1C...Electronic pen, 2...Case, 2in...Internal housing, 21...Case body, 22...Front cap, 23...Rear cap, 3, 3a, 3b...Board holder, 4...Core body, 41...Core rod, 41C...Coil spring for core body, 41L...Extension wire of coil spring for core body, 42...Protective member, 43...Space, 5, 5A, 5B...Transmission member, 51, 51A, 51B...Core body holding member, 51a, 51x...Holding portion, 51b, 51y...Extension portion, 51c...Elastic member, 52...Pressing member, 52a...Pressing head, 52b...Stem-shaped portion, 6...Pressure detection portion, 61...First electrode, 62...Ring-shaped spacer, 63...Dielectric, 64...Second electrode, 64L...Extension wire of second electrode, 65 ...Pressure detection coil spring, 65L...Extension wire of pressure detection coil spring, 66...Pressure detection holding member, 7, 7a, 7b...Pipe-shaped holding member, 8...Printed circuit board, 8s...Transmitter circuit, 8d...Capacitance detection circuit, 9...Battery, 91...Terminal conductor, 9a...Positive terminal, 9b...Negative terminal, 92...Coil spring terminal, 10...Control IC, 11, 12...Side switch, 11a, 12a...Operation unit, 13...Transmitting/receiving electrode, 13C...Coil spring for transmitting/receiving electrode, 13L...Extension wire of coil spring for transmitting/receiving electrode, 14...Ground electrode, 15...Power supply circuit, 16...First ring-shaped elastic member, 17...Second ring-shaped elastic member, 18...Insulating member

Claims (10)

A cylindrical housing with an opening on the pen tip side;
A rod-shaped core body,
a core holder provided in the housing and holding a rear end portion of the core body such that a front end portion of the core body protrudes from the opening of the housing;
an electronic component provided behind the core holder in the housing and realizing an electronic pen function;
a cylindrical internal component part through which the core body passes, on the pen tip side within the housing;
a first ring-shaped elastic member that is in close contact with the entire periphery of the side surface of the internal component and the entire periphery of the inner wall surface of the housing;
and a second ring-shaped elastic member that is in close contact with the entire periphery of the side surface of the core body holding portion and the entire periphery of the inner wall surface of the internal component. 2. The electronic pen according to claim 1,
the first ring-shaped elastic member has a side surface that is in close contact with the inner wall surface of the housing and has an arc shape when cut in a direction along an axial direction passing through the center of the first ring-shaped elastic member;
This electronic pen is characterized in that the second ring-shaped elastic member has a small opening on the pen tip side and a large opening on the rear end side, so that the side surface is inclined, the inner edge of the opening on the pen tip side is in close contact with the entire circumference of the side surface of the core holding portion, and the outer edge of the opening on the rear end side is in close contact with the entire circumference of the inner wall surface of the internal component. 2. The electronic pen according to claim 1,
A pen pressure detection unit is provided behind the core holder,
The core body and the core body holding part which holds the core body are configured to slide in an axial direction in response to a writing pressure applied to the core body and to press the writing pressure detection part,
The second ring-shaped elastic member has a small opening on the pen tip side and a large opening on the rear end side, so that the side surface is inclined, the inner edge of the opening on the pen tip side is in close contact with the entire circumference of the side surface of the core body holding part, and the outer edge of the opening on the rear end side is in close contact with the entire circumference of the inner wall surface of the internal component,
The electronic pen is characterized in that the second ring-shaped elastic member deforms while maintaining close contact with the core body holding portion and with the inner wall surface of the internal component when it slides in the axial direction of the core body and the core body holding portion. 2. The electronic pen according to claim 1,
the core body includes at least a central electrode for transmitting a position indicating signal;
The internal components are at least peripheral electrodes for transmitting signals for detecting the tilt of the electronic pen;
The electronic pen is characterized in that the electronic component includes a first transmitting circuit that generates the position indication signal and supplies it to the central electrode through a first signal line, and a second transmitting circuit that generates the tilt detection signal and supplies it to the peripheral electrode through a second signal line, and the second ring-shaped elastic member is formed from a non-conductive material. 2. The electronic pen according to claim 1,
the core body includes at least a central electrode for transmitting a position indication signal, and a protective member covering the central electrode by a predetermined length from an end of the central electrode on the pen tip side toward a rear end,
the core body holding portion is made of a conductive material and holds a rear end portion of the center electrode,
The internal components are at least peripheral electrodes for transmitting signals for detecting the tilt of the electronic pen;
the electronic component includes a first transmission circuit that generates the position indication signal and supplies the position indication signal to the central electrode through the core body holding portion, and a second transmission circuit that generates the tilt detection signal and supplies the tilt detection signal to the peripheral electrode,
When the core is held by the core holder, at least a portion of the protective member located within the housing is made of a non-conductive material,
the second ring-shaped elastic member is made of a non-conductive material;
An electronic pen comprising: a cylindrical insulating member that is in close contact with a rear end portion of the protective member of the core body and the second ring-shaped elastic member, and that insulates the portion of the core body consisting of the central electrode and the core body holding portion. 2. The electronic pen according to claim 1,
A pen pressure detection unit is provided behind the core body holding unit,
The electronic pen, wherein the core body holding portion comprises a holding portion that holds the core body, and a pressing portion that presses the writing pressure detection portion. 2. The electronic pen according to claim 1,
A pen pressure detection unit is provided behind the core holder,
The electronic pen, characterized in that the core body holding member comprises a holding portion that holds the core body, an extension portion that extends from the rear of the holding portion, and a pressing portion that presses the writing pressure detection portion. 2. The electronic pen according to claim 1,
The electronic pen, wherein one or both of the first ring-shaped elastic member and the second ring-shaped elastic member are made of an elastomer material. A cylindrical housing with an opening on the pen tip side;
A rod-shaped core body including a core rod and a protective member that covers the core rod by a predetermined length from the end of the core rod on the pen tip side toward the rear end;
a core holder provided in the housing and holding a rear end portion of the core body such that a front end portion of the core body protrudes from the opening of the housing;
an electronic component provided behind the core holder in the housing and realizing an electronic pen function;
a cylindrical internal component part through which the core body passes, on the pen tip side within the housing;
an outer ring-shaped elastic member that is in close contact with the entire periphery of the side surface of the internal component and the entire periphery of the inner wall surface of the housing;
an inner ring-shaped elastic member that is in close contact with the entire circumference of a rear end portion of the protective member of the core body and the entire circumference of an inner wall surface of the internal component. 10. The electronic pen according to claim 9,
the core rod is a central electrode for transmitting at least a position indicating signal;
The internal components are at least peripheral electrodes for transmitting signals for detecting the tilt of the electronic pen;
the electronic component includes a first transmission circuit that generates the position indication signal and supplies it to the central electrode, and a second transmission circuit that generates the tilt detection signal and supplies it to the peripheral electrode,
The electronic pen, wherein the inner ring-shaped elastic member is made of a non-conductive material.

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