Electronic pen

Abstract

This invention provides an electronic pen that suppresses initial axial displacement when the pen tip is pressed against the input surface to apply pen pressure. It comprises: a cylindrical pen casing with an opening on the tip side; a core that is mounted with its front end protruding from the opening on the tip side outwards from the pen casing; a pressure detection unit disposed within a hollow portion of the pen casing on the rear end side, opposite in the axial direction to the front end of the core, for detecting pressure applied to the front end of the core; and an elastic member configured to apply force to the core in the hollow portion of the pen casing towards the side opposite in the axial direction to the tip side, even when no pressure is applied to the front end of the core.

Description

Technical Field

[0001] The present invention relates to an electronic pen having a pressure detection unit that detects the pressure (pen pressure) applied to the front end of the core. Background Technology

[0002] A coordinate input system consisting of a position detection device with a position detection sensor and an electronic pen can use various methods, such as electromagnetic coupling and electrostatic coupling, depending on the way the signal is exchanged between the position detection sensor and the electronic pen.

[0003] Electronic pens used in such coordinate input systems are generally configured to detect pressure (pen pressure) applied to the tip of the core and transmit it to a position detection device. In this case, to detect the pressure applied to the core, the tip of the core protrudes from an opening in the pen housing (hereinafter referred to as the pen housing), and the core is configured to move along its axial direction within the hollow portion of the pen housing. Furthermore, a pressure detection unit is provided on the rear end side, opposite to the tip of the core in the axial direction. This pressure detection unit detects the axial displacement of the core corresponding to the pressure applied to the tip as an electrical change such as a change in capacitance, inductance, or resistance.

[0004] Pressure detection units that detect changes in electrostatic capacitance include: structures in which the contact area between a dielectric and a conductive elastic member changes according to the applied pressure, thereby changing the electrostatic capacitance (for example, see Patent Document 1 (Japanese Patent Application Publication No. 2011-186803)); and structures made of semiconductor devices in which the distance between two electrodes facing each other separated by an air layer that serves as a dielectric changes according to the applied pressure (for example, see Patent Document 2 (Japanese Patent Application Publication No. 2013-161307)).

[0005] Furthermore, pressure detection units that detect changes in inductance by measuring the displacement of the core in the axial direction under applied pressure are also known (see, for example, Patent Document 3 (Japanese Patent Application Publication No. 2017-216002)). Moreover, pressure detection units that detect changes in resistance by measuring the displacement of the core in the axial direction under applied pressure use strain gauges (see, for example, Patent Document 4 (Japanese Patent Application Publication No. 2019-016038)).

[0006] In an electronic pen, the front end of the pen's core contacts the input surface of a position detection sensor. Pressing the front end of the pen's core relative to the input surface applies pressure to the front end of the core. A pressure detection unit detects the pressure applied to the front end of the core. Furthermore, in a coordinate input system, the position detection device receives information corresponding to the pressure detected by the pen's pressure detection unit and outputs it as information about the pen pressure value applied to the front end of the pen's core.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2011-186803

[0010] Patent Document 2: Japanese Patent Application Publication No. 2013-161307

[0011] Patent Document 3: Japanese Patent Application Publication No. 2017-216002

[0012] Patent Document 4: Japanese Patent Application Publication No. 2019-016038 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] However, recently, with the popularization of position detection devices, electronic pens have begun to be used as a substitute for writing tools such as pencils that leave writing marks on paper. Electronic pens are required to have the same ease of use as writing tools such as pencils.

[0015] In the past, in electronic pens, when the pen tip was not pressed against the input surface of the position detection device (in a state of not contacting the input surface), the core was either in a state of being subjected to force in a direction away from the pressure detection part, or in a free state of not being subjected to any force.

[0016] Therefore, in an electronic pen, when the pen tip is never pressed against the input surface of the position detection device (in a state of no contact with the input surface) and pen pressure is applied by pressing the pen tip against the input surface, an initial displacement in the axial direction of the core is generated. In the case of writing instruments such as pencils and ballpoint pens, no such displacement is generated at all, so there is a problem that the user may perceive this displacement as a so-called wobbling in the axial direction, which may cause discomfort.

[0017] The purpose of this invention is to provide an electronic pen that can solve the above-mentioned problems.

[0018] Methods for solving problems

[0019] To address the aforementioned issues, an electronic pen is provided, characterized by comprising: a cylindrical pen casing with an opening on the tip side; a core body, assembled with its front end protruding from the opening on the tip side toward the outside of the pen casing; a pressure detection unit disposed within the hollow portion of the pen casing at the rear end of the core body, opposite in the axial direction to the front end, for detecting pressure applied to the front end of the core body; and an elastic member configured to apply force to the core body within the hollow portion of the pen casing in the opposite direction to the tip side, even when no pressure is applied to the front end.

[0020] According to the structure described above, the electronic pen, through the elastic member, applies force to the core in the hollow part of the pen shell in the opposite direction to the axial direction of the pen tip, even when no pressure is applied to the tip. Therefore, it produces almost no initial axial displacement as when pressure is applied (pen pressure) by pressing the pen tip against the input surface. Thus, users can enjoy the same ease of use as writing instruments such as pencils with the electronic pen. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating a structural example of the first embodiment of the electronic pen of the present invention.

[0022] Figure 2 It is used for explanation Figure 1 An exploded perspective view of a portion of the structure of the electronic pen according to the first embodiment.

[0023] Figure 3 It is used for explanation Figure 1 An exploded perspective view of a portion of the structure of the electronic pen according to the first embodiment.

[0024] Figure 4 This is a diagram illustrating a structural example of the main parts of the electronic pen according to a second embodiment of the present invention.

[0025] Figure 5 This is a diagram illustrating a structural example of the main parts of the electronic pen according to a third embodiment of the present invention.

[0026] Figure 6 This is a characteristic diagram illustrating the main parts of the fourth embodiment of the electronic pen of the present invention.

[0027] Figure 7 This is a diagram illustrating a structural example of the main parts of the fourth embodiment of the electronic pen of the present invention.

[0028] Figure 8 This is a diagram showing a portion of a flowchart illustrating the operation of the main parts of the electronic pen used to explain the fourth embodiment of the present invention.

[0029] Figure 9 This is a diagram showing a portion of a flowchart illustrating the operation of the main parts of the electronic pen used to explain the fourth embodiment of the present invention.

[0030] Figure 10 This is a diagram illustrating a structural example of the main parts of another embodiment of the electronic pen of the present invention. Detailed Implementation

[0031] Hereinafter, several embodiments of the electronic pen of the present invention will be described with reference to the accompanying drawings. The embodiments of the electronic pen described below are of the case of an active electrostatic capacitive electronic pen.

[0032] [First Implementation Method]

[0033] <Summary of the electronic pen in the first embodiment>

[0034] Figure 1 Figure (A) is a side view of an example of the appearance of the electronic pen 1 according to the first embodiment. Additionally, Figure 1 (B) is based on Figure 1 The AA line of (A) is an enlarged cross-sectional view of the part of the pen tip side after the electronic pen 1 has been cut.

[0035] In this embodiment, the electronic pen 1 is housed within the hollow space of the elongated cylindrical pen casing 2, such as... Figure 1 As shown by the dashed line in (A), the main body unit 3 of the electronic pen, which houses an active electrostatic capacitor, is configured to house a primary battery 4 in this example. In this case, as... Figure 1 As shown by the dashed line in (A), in the electronic pen 1 of this embodiment, the main body unit 3 is disposed on the pen tip side in the axial direction of the hollow space of the pen shell 2, and the primary battery 4 is disposed on the rear end side opposite to the pen tip side.

[0036] The pen casing 2 includes: a cylindrical shell portion 21 made of a conductive material of a certain diameter, such as SUS; a conical sleeve portion 22 formed and tapering towards the pen tip side, which is coupled to the cylindrical shell portion 21; and a rear end closure portion 23 coupled to the rear end side of the cylindrical shell portion 21 in the axial direction. The sleeve portion 22 and the rear end closure portion 23 are made of an insulating material, in this example, resin. Furthermore, in this embodiment, the cylindrical shell portion 21 made of conductive material is electrically connected to the ground conductor of the circuit board 34, which will be described later.

[0037] The sleeve portion 22 has a space communicating with the hollow space of the cylindrical shell portion 21, and the pointed front end side forms an opening 22a (see reference). Figure 1(B)), the opening 22a becomes the opening on the tip side of the pen shell 2. Furthermore, in the electronic pen 1 of this embodiment, the conductive core 5 is mounted on the tip-side component 32 of the electronic pen 1 in a state where its front end 5a protrudes outward from the opening 22a of the sleeve portion 22.

[0038] The rear end closure 23 is fitted into the cylindrical housing portion 21 in such a way that it closes the opening on the rear end side of the cylindrical housing portion 21. In this example, the rear end closure 23 is as follows: Figure 1 As shown in (A), it has a pen clip 23a and is configured to be detachable from the cylindrical housing 21.

[0039] In the electronic pen 1 of this embodiment, the battery 4 can be stored or removed relative to the battery storage section 4a inside the cylindrical housing 21 when the rear end closure 23 is removed from the cylindrical housing 21. Furthermore, when the battery 4 is stored in the battery storage section 4a inside the cylindrical housing 21, the battery 4 can be secured in the battery storage section 4a inside the cylindrical housing 21 by fitting the rear end closure 23 into the cylindrical housing 21.

[0040] The main body unit 3 is located in the space of the hollow part of the cylindrical shell 21, which is closer to the pen tip than the battery storage part 4a. The main body unit 3 is fixedly arranged in such a way that it does not move along the axial direction within the hollow part of the pen shell 2.

[0041] In this example, the main body unit 3 includes a boat-shaped resin unit support 31 with the pen shell 2 as its length direction, and a pen tip side component 32 is mounted on the pen tip side of the unit support 31. Furthermore, a substrate mounting portion 33 is located between the pen tip side component 32 of the unit support 31 and the battery storage portion 4a, and an elongated rectangular circuit board 34 is mounted and held on the substrate mounting portion 33.

[0042] like Figure 1 As shown in (A), an electronic circuit 340 is provided on the circuit board 34, including a signal transmission circuit that transmits signals sent through the core 5 to the position detection sensor of the position detection device. Furthermore, the voltage from the primary battery 4 housed in the battery storage section 4a is supplied to the electronic circuit 340 as a power supply voltage. Additionally, in the electronic pen 1 of this embodiment, as described later, peripheral electrodes 6 are provided around the core 5 (see reference 1). Figure 1 (B)). In this embodiment, the peripheral electrode 6 is configured to receive signals from the position detection sensor for timing control of signals exchanged between the sensor and the position detection device, and to send signals to the position detection sensor for detecting the tilt of the electronic pen 1 in the position detection device.

[0043] <Example of the internal structure of the tip side of the first electronic pen 1>

[0044] Next, refer to Figure 1 The enlarged cross-sectional view of the pen tip side of (B) illustrates an example of the internal structure of the pen tip side of the electronic pen 1 according to the first embodiment.

[0045] like Figure 1 As shown in (B), as described above, the sleeve portion 22 has a space communicating with the hollow space of the cylindrical housing portion 21, but the opening on the opposite side of the pen tip side has an annular protrusion 22b that protrudes in an annular shape along the axial direction. The outer diameter of the annular protrusion 22b is equal to or slightly smaller than the inner diameter of the cylindrical housing portion 21. The annular protrusion 22b is inserted into and fitted into the cylindrical housing portion 21 and properly engaged, thereby combining the sleeve portion 22 and the cylindrical housing portion 21 to form the pen shell 2.

[0046] And, as Figure 1 As shown in (B), the pen tip side component 32 of the main body unit 3 is provided in the hollow space of the cylindrical shell part 21 and the hollow space of the sleeve part 22 which communicates with the hollow space of the cylindrical shell part 21. Figure 2 This is an exploded perspective view illustrating an example of the structure of the nib-side component 32. Referring also to this view below... Figure 2 Please provide an explanation.

[0047] In this embodiment, such as Figure 1 As shown in (B), the pen tip side component 32 holds the peripheral electrode 6 on the pen tip side and is composed of a core support 7, a pressure transmission member 8, a pressure detection unit (pen pressure detection unit) 9, and a core 5 that is detachably mounted relative to the core support 7.

[0048] The peripheral electrode 6 is made of a conductive material, such as a conductive metal, and is cylindrical. As described later, it is arranged to surround the rear end side, which is opposite to the front end of the core 5, including the conductive central electrode. In this example, it serves as an electrode that receives signals from the position detection sensor side and sends signals to the position detection sensor.

[0049] like Figure 1As shown in (B), the pen tip-side component 32 includes a component housing and holding bracket 321 that forms the outer shell of the pen tip-side component 32. This component housing and holding bracket 321 has a cylindrical shape, and the diameter (outer diameter) of its outer peripheral surface is approximately equal to or slightly smaller than the diameter (inner diameter) of the inner wall surface of the sleeve portion 22. Furthermore, around the outer peripheral surface of the opening 321a at the rear end of the component housing and holding bracket 321, a flange portion 321b is formed, consisting of protrusions in a direction orthogonal to the axial direction. This flange portion 321b is configured such that, by engaging with the annular protrusion 22b at the rear end of the sleeve portion 22, the pen tip-side component 32 cannot move towards the pen tip side along the axial direction within the pen shell 2 of the electronic pen 1. Therefore, when the flange portion 321b of the component housing and holding bracket 321 is engaged with the annular protrusion 22b at the rear end of the sleeve portion 22, as... Figure 1 As shown in (B), the outer peripheral side of the component housing and holding bracket 321 is in close contact with the inner wall of the sleeve portion 22, without any gap between them.

[0050] like Figure 1 As shown in (B), the peripheral electrode 6 is held in a peripheral electrode holding member 322 having an outer peripheral surface having a diameter (inner diameter) that is approximately equal to or slightly smaller than the inner wall surface of the component housing and holding bracket 321, forming part of the pen tip side component 32. The peripheral electrode holding member 322 is made of elastic resin and is partially protruding from the pen tip side of the component housing and holding bracket 321 toward the pen tip side, configured to hold the peripheral electrode 6 by the portion protruding toward the pen tip side.

[0051] In this embodiment, such as Figure 1 As shown in (B), the peripheral electrode 6 includes: a tapered portion 6a, the outer diameter of which corresponds to the gradually decreasing inner diameter of the sleeve portion 22 on the tip side; and a rear end portion 6b, the outer and inner diameters of which are constant. In this case, the inner diameter of the tapered portion 6a of the peripheral electrode 6 is set to a constant diameter that is smaller than the inner diameter of the rear end portion 6b. Therefore, inside the peripheral electrode 6, as... Figure 1 As shown in (B), a stepped portion 6c is formed at the boundary between the tapered portion 6a and the rear end side portion 6b. Additionally, as... Figure 1 (B) and Figure 2 As shown, a flange portion 6d with a protrusion orthogonal to the axial direction is formed around the opening of the rear end side portion 6b of the peripheral electrode 6.

[0052] The diameter (inner diameter) of the inner wall surface of the peripheral electrode holding member 322 is set to be equal to or slightly smaller than the outer diameter of the rear end side portion 6b of the peripheral electrode 6, and a step portion 322a is formed on the inner wall surface of the peripheral electrode holding member 322 to engage with the flange portion 6d of the peripheral electrode 6. A portion of the rear end side portion 6b of the peripheral electrode 6 is inserted into the peripheral electrode holding member 322, and the flange portion 6d engages with the step portion 322a on the inner wall surface of the peripheral electrode holding member 322, thereby holding the peripheral electrode 6 by the peripheral electrode holding member 322.

[0053] Furthermore, in this embodiment, such as Figure 1 As shown in (B), with the main body unit 3 housed within the pen casing 2, the tapered portion 6a of the peripheral electrode 6 is in contact with the inner wall surface of the sleeve portion 22. In this case, in this embodiment, the portion of the inner wall surface of the tapered sleeve portion 22 corresponding to the rear end side portion 6b of the peripheral electrode 6 is configured to have a cylindrical inner wall portion 22c, which is configured to fit with the outer peripheral surface of the rear end side portion 6b of the peripheral electrode 6 and have a constant inner diameter. Thus, the outer peripheral surface of the rear end side portion 6b of the peripheral electrode 6 and the inner wall surface of the cylindrical inner wall portion 22c of the inner wall surface of the sleeve portion 22 are either in contact or separated by a small gap.

[0054] Furthermore, in this embodiment, such as Figure 1 (B) and Figure 2 As shown, an O-ring 13 made of an elastic material, such as elastic rubber, is provided on the outer peripheral surface of the rear end side 6b of the peripheral electrode 6. In the portion of the O-ring 13, there is no gap between the cylindrical inner wall portion 22c of the inner wall of the sleeve portion 22 and the outer peripheral surface of the rear end side 6b of the peripheral electrode 6. Through the O-ring 13, the space closer to the pen tip (the space communicating with the external space of the electronic pen 1) is completely separated from the hollow space inside the pen casing 2 further back than the O-ring 13, thus achieving moisture protection for the electronic pen 1.

[0055] And, as Figure 1 As shown in (B), the core support 7, pressure transmission member 8, and pressure detection unit (pen pressure detection unit) 9 are arranged in series in the axial direction with their central axes aligned, within the hollow space of the peripheral electrode 6 held by the peripheral electrode holding member 322 mounted on the component housing and holding bracket 321 and the hollow space of the component housing and holding bracket 321 communicating with the hollow space of the peripheral electrode 6. In this embodiment, as will be described in detail later, the pressure detection unit 9 is housed in the pressure detection unit bracket 91.

[0056] like Figure 1 (B) and Figure 2As shown, a pressure detection unit support storage section 310 for storing and holding the pressure detection unit support 91 is provided on the pen tip side of the unit support 31. Furthermore, as... Figure 1 As shown in (B), a portion of the pressure detection bracket storage portion 310 of the unit bracket 31 is inserted into and held on the rear end side of the component storage and holding bracket 321.

[0057] like Figure 2 As shown, the pressure detection unit support storage portion 310 includes: a cylindrical portion 311 with an opening 311a on the pen tip side; and a storage space portion 312 having a storage space communicating with the hollow space of the cylindrical portion 311. The pressure detection unit support 91 is stored in the hollow space of the cylindrical portion 311 and the storage space of the storage space portion 312 of the pressure detection unit support storage portion 310.

[0058] like Figure 2 As shown, the pressure sensing bracket 91 has a cylindrical shape, and a receiving recess 91a is formed in the middle of the cylindrical shape in the axial direction as a recess in a direction orthogonal to the axial direction. Furthermore, as... Figure 1 (B) and Figure 2 As shown, on the pen tip side of the pressure detection unit bracket 91, a through hole 91b is formed in the center of its cylindrical shape, which is spatially connected to the receiving recess 91a and is arranged along the axial direction.

[0059] In addition, such as Figure 1 (B) and Figure 2 As shown, a recess 91c in the axial direction is formed on the rear end side of the pressure detection unit bracket 91, and a columnar protrusion 91d extending axially from the center of the bottom of the recess 91c is formed. Furthermore, in this embodiment, a helical spring 92 with a winding diameter larger than the outer diameter of the columnar protrusion 91d is provided, such as... Figure 1 As shown in (B), the helical spring 92 is mounted in such a way that it is wound around the columnar protrusion 91d.

[0060] The helical spring 92 acts as a shock absorber, absorbing impact loads applied to the front end of the core 5 when the electronic pen 1 of this embodiment is dropped. The helical spring 92 has the following elastic modulus: it does not elastically displace when pen pressure is applied to the front end of the core 5 of the electronic pen 1 during writing input, and only elastically displaces when an impact load greater than the pen pressure is applied.

[0061] like Figure 1 (B) and Figure 2 As shown, a partition 313 orthogonal to the axial direction is provided on the rear end side of the storage space 312 of the pressure detection unit bracket storage section 310. For example... Figure 1As shown in (B), a recess 313a with the same diameter as the recess 91c of the pressure sensing unit bracket 91 and a through hole 313b are provided in the axial direction of the partition wall 313. The diameter of the through hole 313b is larger than the diameter of the columnar protrusion 91d on the rear end side of the pressure sensing unit bracket 91, but smaller than the outer diameter of the winding diameter of the coil spring 92. That is, the diameter of the through hole 313b is determined such that, due to the presence of the partition wall 313, the end of the rear end side of the coil spring 92 cannot move in the axial direction.

[0062] In this embodiment, the pressure detection unit 9 uses a semiconductor device (see the aforementioned Patent Document 2) where the distance between two electrodes facing each other, separated by an air layer that serves as a dielectric, varies according to the applied pressure. Figure 2 As shown, the pressure detection unit 9 includes a pressure-bearing protrusion 9a that can withstand the pressure to be detected. This pressure-bearing protrusion 9a is configured to shift the distance between two electrodes facing each other across an air layer according to the pressure to be detected, but returns to its original state if the pressure to be detected disappears. This structure is known as shown in Patent Document 2, and therefore its description is omitted here.

[0063] In this embodiment, such as Figure 1 (B) and Figure 2 As shown, the pressure detection unit 9 is mounted at one end of the elongated flexible substrate 93 along its length. In this case, the pressure detection unit 9 is disposed on the flexible substrate 93 with the opposing directions of the two electrodes facing each other across an air layer being orthogonal to the substrate surface of the flexible substrate 93.

[0064] Furthermore, the pressure detection unit 9 is housed and fixed to the pressure detection unit bracket 91 in the following manner. First, the pressure detection unit bracket 91, with a coil spring 92 installed around the columnar protrusion 91d, is inserted into the cylindrical portion 311 of the pressure detection unit bracket storage portion 310 of the unit bracket 31 from the opening 311a side. Then, the pressure detection unit bracket 91 is aligned such that the opening of the storage space portion 312 of the pressure detection unit bracket storage portion 310 and the opening of the storage recess 91c of the pressure detection unit bracket 91 are at the same position (overlapping position), and the pressure detection unit bracket 91 is inserted from the opening 311a side of the cylindrical portion 311 of the pressure detection unit bracket storage portion 310.

[0065] At this time, as Figure 1As shown in (B), the columnar protrusion 91d of the pressure detection unit bracket 91 is inserted into the recess 313a and through hole 313b of the partition wall 313 of the pressure detection unit bracket housing 310. In this state, the end of the coil spring 92 is in contact with the wall surface of the partition wall 313. Through the elastic offset force of the coil spring 92, the pressure detection unit bracket 91 is elastically displaced towards the pen tip side, and becomes locked in the axial direction when normal pen pressure is applied to the front end 5a of the core 5 of the electronic pen 1. When an impact load is applied to the front end 5a side of the core 5, the coil spring 92 contracts to absorb the impact load.

[0066] Moreover, such as Figure 2 As indicated by the middle arrow, the pressure sensing unit 9, disposed on the flexible substrate 93, is inserted into the receiving recess 91a of the pressure sensing unit bracket 91 from the opening side of the receiving space 312. In this case, the portion of the flexible substrate 93 on which the pressure sensing unit 9 is mounted is bent relative to the other portions of the flexible substrate 93, such that the two electrodes constituting the semiconductor device of the pressure sensing unit 9 are facing each other in the axial direction separated by an air layer, and the pressure sensing unit 9 is inserted and housed in the receiving recess 91a of the pressure sensing unit bracket 91. In this housed state, as... Figure 1 As shown in (B), the surface of the pressure detection unit 9 with the pressure protrusion 9a faces the through hole 91b of the pressure detection unit bracket 91, and the position of the pressure protrusion 9a is the center position of the through hole 91b.

[0067] In this embodiment, the pressure detection unit 9 is configured to receive pressure (pen pressure) applied to the front end of the core 5 via the core support 7 and the pressure transmission member 8. In this embodiment, the pressure transmission member 8 is made of a non-conductive material such as resin, and consists of a pressing member 81 and a pressing component 82 that presses the pressing member 81 in the axial direction. Figure 1 As shown in (B), these pressing elements 81 and pressing components 82 are housed in a transfer member bracket 83 provided in the peripheral electrode holding member 322 in a state in which they can move along the axial direction.

[0068] In this case, the pressing member 81 of the pressure transmission member 8 is configured to insert through the through hole 91b of the pressure detection unit bracket 91 and engage with the pressure-receiving protrusion 9a of the pressure detection unit 9. The pressing member 82 has a recess 82a for engaging with the engagement protrusion 7d of the core bracket 7 (described later). Furthermore, when pressure is applied to the front end 5a of the core 5, the pressure is transmitted to the pressing member 82 of the pressure transmission member via the core bracket 7. Through the pressing member 82, the pressing member 81 presses the pressure-receiving protrusion 9a of the pressure detection unit 9, thereby changing the electrostatic capacitance of the semiconductor device constituting the pressure detection unit 9, and detecting the pressure based on the change in electrostatic capacitance.

[0069] like Figure 1 As shown in (B), in this example, the core 5 is configured to cover most of the central electrode 51, which is formed of a conductive material, except for the rear end side, with a protective member 52 formed of a non-conductive material. Figure 1 (B) and Figure 2 As shown, the front end 5a of the core 5 is formed such that the oval portion of the central electrode 51 is covered by a protective member 52, resulting in a conical shape with a tapered portion that tapers towards the front end. Furthermore, as... Figure 1 As shown in (B), the diameter of the core 5 is smaller than the diameter of the opening 22a (the opening of the pen shell 2) of the sleeve portion 22 on the rear end side than the front end 5a, and the rear end of the center electrode 51 is exposed without being covered by the protective member 52.

[0070] In this case, such as Figure 1 As shown in (B), the core 5 has a structure in which a space (air layer) 53 is provided between the central electrode 51 and the protective member 52. The signal (electric field) emitted from the wider portion of the oval-shaped pen tip of the core 5 is emitted more efficiently only through the protective member 52. However, the signal (electric field) emitted from the narrower portion of the oval-shaped pen tip of the central electrode 51 is suppressed by the space 53 and the protective member 52. This is because the space 53 and the protective member 52 have different dielectric constants, and this portion functions like a double capacitor. Therefore, even when the electronic pen 1 is tilted relative to the input surface of the position detection sensor, a good signal that does not become too wide can be sent from the central electrode 51.

[0071] like Figure 1 As shown in (B), the core 5, with its rear end portion 5a further back than the front end portion 5a, is inserted into the internal space of the peripheral electrode 6 inside the pen casing 2 through the opening 22a of the sleeve portion 22. Furthermore, the rear end of the center electrode 51, which is not covered by the protective member 52, is fitted into the core support 7. In this case, the non-conductive protective member 52 of the core 5 serves as an insulator between the center electrode 51 and the peripheral electrode 6.

[0072] Furthermore, in this embodiment, when the core 5 is inserted into the sleeve portion 22 of the pen casing 2, as... Figure 1 As shown in (B), the front end 6e of the peripheral electrode 6 on the tip side abuts against the side circumferential surface of the protective member 52 at the small-diameter portion behind the front end 5a of the core 5, and the core 5 is restricted to not move in a direction orthogonal to the axial direction at this abutment portion. Due to this structure, as Figure 1As shown in (B), the front end 6e of the peripheral electrode 6 on the tip side protrudes inward, and the size of the opening on the tip side of the peripheral electrode 6 is approximately equal to or slightly larger than the diameter of the contact portion of the core 5. Therefore, the core 5 will not wobble in a direction orthogonal to the axis at the opening on the tip side of the peripheral electrode 6.

[0073] When pressure is applied to the front end 5a of the core 5, the core support 7 becomes an integral part of the core 5 and moves in the axial direction, thereby transmitting the pressure to the pressure detection unit 9 via the pressure transmission member 8, and also serves to make electrical connections between the central electrode 51 of the core 5 and the electronic circuit 340 disposed on the circuit board 34.

[0074] Furthermore, in this embodiment, the core support 7 is configured to always apply force to the pressure detection unit 9, as described below, thereby preventing the core 5, which is fitted with the core support 7, from wobbling in the axial direction.

[0075] Figure 3 This diagram shows the core support 7 and its surrounding components arranged in the hollow space of the peripheral electrode 6 and the transmission component support 83. It is used to illustrate the two functions of the core support 7 mentioned above and the structure used to prevent swaying of the core 5 in the axial direction.

[0076] The core support 7 is made of resin mixed with conductive material, in this example, conductive metal powder, such as... Figure 1 (B) and Figure 3 As shown, the core 5 has a large-diameter portion 7b, which includes a fitting recess 7a for engaging the rear end of the center electrode 51 of the core 5. The exposed portion of the center electrode 51 at the rear end of the core 5 is pressed into the fitting recess 7a of the large-diameter portion 7b, thereby securing the core 5 to the core support 7. Therefore, if pressure is applied to the front end 5a of the core 5 and the core 5 displaces in the axial direction, the core support 7 also displaces in the axial direction, transmitting the pressure to the pressure detection unit 9. Furthermore, while the core 5 is held by the core support 7, it can be removed from the core support 7 by pinching and pulling the tip portion, for example, by hooking it onto a fingernail. In other words, the core 5 can be replaced.

[0077] Furthermore, the core support 7 has a small-diameter portion 7c on the rear end side of the large-diameter portion 7b with the fitting recess 7a, and a helical spring 7e made of conductive metal is wound and installed on this small-diameter portion 7c. One end of the helical spring 7e is locked in place at the step between the large-diameter portion 7b and the small-diameter portion 7c of the core support 7 in a manner electrically connected to the core support 7. Furthermore, as... Figure 2As shown, the other end of the helical spring 7e extends along the axial direction, passes through the through hole 311b of the cylindrical portion 311 of the pressure detection portion bracket housing portion 310 provided in the unit bracket 31, and reaches the circuit board 34. Moreover, the other end of the helical spring 7e is electrically connected to the electronic circuit 340 disposed on the circuit board 34.

[0078] like Figure 1 (B) and Figure 3 As shown, a fitting protrusion 7d with a smaller diameter than the smaller diameter portion 7c is provided on the rear end side of the core support 7. As previously described, this fitting protrusion 7d engages with the recess 82a of the pressing member 82 of the pressure transmission member 8, and the core support 7 and the pressure transmission member 8 are joined in the axial direction. In this case, in this embodiment, the smaller diameter portion 7c of the core support 7 is as follows... Figure 1 As shown in (B), it is inserted into the transfer member bracket 83. Therefore, the helical spring 7e provided around the small diameter portion 7c is also housed in the transfer member bracket 83. Moreover, the extension of the helical spring 7e extends towards the circuit board 34 by inserting through the transfer member bracket 83.

[0079] Furthermore, in this embodiment, such as Figure 1 (B) and Figure 2 As shown, a helical spring 6f for electrical connection between the peripheral electrode 6 and the circuit board 34 is disposed around the pen tip side portion of the transmission member support 83. Figure 1 (B) and Figure 2 As shown, one end of the helical spring 6f is electrically connected to the peripheral electrode 6. Additionally, the other end of the helical spring 6f extends, with its extension 6t (see reference). Figure 2 The transmission member bracket 83 inside the peripheral electrode holding member 322 extends towards the circuit board 34 and connects to the electronic circuit 340 and signal receiving circuit (not shown) of the circuit board 34.

[0080] Next, the structure for preventing the core 5 from wobbling along its axis will be explained. For example... Figure 1 As shown in (B), in this embodiment, the large diameter portion 7b of the core support 7, which is fitted with the fitting recess 7a of the core support 7 at the rear end of the center electrode 51 of the core 5, is located in the hollow space of the rear end side portion 6b of the peripheral electrode 6 with a certain inner diameter.

[0081] In this embodiment, such as Figure 1As shown in (B), in the rear end side 6b of the peripheral electrode 6, as an example of an insulating component for ensuring electrical insulation between the peripheral electrode 6 and the large-diameter portion 7b of the core support 7, a cup-shaped component 10 made of resin is provided. The outer diameter of the cup-shaped component 10 is equal to or slightly smaller than the inner diameter of the rear end side 6b of the peripheral electrode 6. Furthermore, the inner diameter of the recess 10b of the cup-shaped component 10 is larger than the diameter of the large-diameter portion 7b of the core support 7.

[0082] Therefore, the cup-shaped member 10 is disposed within the rear end portion 6b of the peripheral electrode 6 with the periphery of its tip-side end face facing the stepped portion 6c inside the peripheral electrode 6. In this case, in this embodiment, between the periphery of the tip-side end face of the cup-shaped member 10 and the stepped portion 6c inside the peripheral electrode 6, such as Figure 1 As shown in (B), in this example, an O-ring 12 with a circular cross-section is provided in a state of elastic compression and elastic deformation (see reference). Figure 2 and Figure 3 The O-ring 12 also serves to separate the space on the tapered portion 6a side, which is connected to the external space inside the peripheral electrode 6, from the space on the rear end portion 6b side of the peripheral electrode 6.

[0083] Furthermore, the large-diameter portion 7b of the core support 7 is inserted into the recess 10b of the cup-shaped member 10 in a state that allows it to move along the axial direction. For example... Figure 1 (B) and Figure 3 As shown, at the bottom of the recess 10b of the cup-shaped component 10, a through hole 10a is provided for the rear end of the central electrode 51 of the core 5 to be inserted. The rear end of the central electrode 51 of the core 5 passes through the through hole 10a and is pressed into the fitting recess 7a of the large-diameter portion 7b of the core support 7 disposed in the recess 10b of the cup-shaped component 10. Therefore, the core 5 can move along the axial direction toward the pressure detection unit 9 together with the core support 7 in the internal space of the peripheral electrode 6 and the recess 10b of the cup-shaped component 10.

[0084] In this case, the cup-shaped component 10 is engaged within the peripheral electrode 6, which is mounted within the pen housing 2 in a manner that prevents it from moving towards the axial tip. Therefore, the cup-shaped component 10 also does not move towards the axial tip within the pen housing 2. Consequently, the bottom wall of the recess 10b of the cup-shaped component 10 becomes a wall surface that does not move towards the axial tip within the pen housing 2.

[0085] Furthermore, in this embodiment, the core support 7 is combined with the pressure transmission member 8, and the pen tip side component 32 is formed on the pen tip side of the unit support 31 when the pressing member 81, which serves as the pressure transmission member 8, abuts against the pressure-receiving protrusion 9a of the pressure detection unit 9. In this case, in this embodiment, in the pen tip side component 32, as... Figure 1 As shown in (B), the configuration is such that a gap is formed between the inner wall surface surrounding the through hole 10a at the bottom of the cup-shaped member 10 and the annular end face 7t surrounding the fitting recess 7a of the large-diameter portion 7b of the core support 7. Furthermore, in this embodiment, as... Figure 1 (B) and Figure 3 As shown, in this gap, as an example of an elastic member, an O-ring 11 made of elastic rubber is provided.

[0086] In this example, the diameter of the circular cross-section of the O-ring 11 is slightly larger than the gap between the inner wall surface around the through hole 10a at the bottom of the cup-shaped member 10 and the annular end face 7t around the fitting recess 7a of the large diameter portion 7b of the core support 7. Therefore, the O-ring 11 is arranged in a state of elastic compression and elastic deformation, at least in the axial direction, within the gap between the inner wall surface around the through hole 10a at the bottom of the cup-shaped member 10 and the annular end face 7t around the fitting recess 7a of the large diameter portion 7b of the core support 7.

[0087] As described above, the bottom wall of the recess 10b of the cup-shaped component 10 remains in a state where it does not move towards the tip in the axial direction within the pen casing 2. Therefore, due to the elastic restoring force of the O-ring 11 in its elastically deformed state, the core support 7 is always in a state where it is subjected to force towards the pressure detection unit 9 in the axial direction. Consequently, the core 5, which is fitted with the core support 7, is also always in a state where it is subjected to force towards the pressure detection unit 9 in the axial direction when no pressure is applied to the front end 5a.

[0088] Furthermore, in this embodiment, the diameter of the outer circumference of the O-ring 11 is selected to be equal to or slightly larger than the inner diameter of the recess 10b of the cup-shaped member 10. However, in this example, the diameter of the inner circumference of the O-ring 11 is a diameter that does not contact the rear end of the central electrode 51 of the core 5.

[0089] Therefore, the O-ring 11 is in contact with the wall portion of the recess 10b of the cup-shaped member 10 in the axial direction. Thus, when the O-ring 11 is elastically compressed and elastically deformed in the axial direction within the gap between the inner wall surface around the through hole 10a at the bottom of the cup-shaped member 10 and the annular end face 7t around the fitting recess 7a of the large-diameter portion 7b of the core support 7, it elastically deforms in a slightly elongated manner in a direction orthogonal to the axial direction. That is, an elastic offset force towards the center of the O-ring 11 acts on the O-ring 11. This elastic offset force towards the center of the O-ring 11 becomes a force that suppresses the displacement (wobbling) of the core support 7 in a direction orthogonal to the axial direction.

[0090] As described above, in the electronic pen 1 of this embodiment, even when no pressure is applied to the front end 5a, the elastic restoring force of the O-ring 11 in its elastically deformed state always applies force towards the pressure detection unit 9 in the axial direction. Therefore, even when the front end 5a of the core 5 is never pressed against the input surface of the position detection device, and pen pressure is applied by pressing the front end 5a against the input surface, no initial displacement in the axial direction of the core occurs, preventing the user from feeling so-called wobbling in the axial direction. Therefore, the electronic pen 1 according to this embodiment can achieve the same user experience as writing instruments such as pencils and ballpoint pens.

[0091] Furthermore, in this embodiment, the displacement of the core support 7 in the direction orthogonal to the axial direction is also suppressed by the elastic offset force of the compressed O-ring 11. Therefore, the core 5, which is fitted into the core support 7, also suppresses displacement (wobbling) in the direction orthogonal to the axial direction. In this embodiment, the axial displacement of the core 5 is also suppressed by the front end 6e on the tip side of the peripheral electrode 6. Therefore, through both, the suppression of displacement in the direction orthogonal to the axial direction of the core 5 can be achieved more firmly.

[0092] Furthermore, in achieving the effect of suppressing displacement of the tip end portion 6e of the peripheral electrode 6 in a direction orthogonal to the axial direction of the core 5, it is necessary to precisely determine the size of the opening of the portion forming the tip end portion 6e of the peripheral electrode 6. Sometimes, due to tolerances, the suppression effect cannot be fully realized. However, in this embodiment, due to the presence of the O-ring 11, the effect of suppressing displacement in a direction orthogonal to the axial direction of the core 5 can be fully realized. Moreover, even with only the O-ring 11, the effect of suppressing displacement in a direction orthogonal to the axial direction of the core 5 can be obtained, so the tip end portion 6e of the peripheral electrode 6 can be omitted.

[0093] Furthermore, in this embodiment, the O-ring 11 also serves to separate the internal space of the pen casing 2 on the rear end side of the cup-shaped component 10 from the external space communicating with the pen tip side through the through hole 10a of the cup-shaped component 10. Therefore, in the electronic pen 1 of this embodiment, the hollow space inside the pen casing 2 and the space communicating with the external space on the pen tip side can be separated by the O-ring 11 and the two O-rings 12 and 13 described above. As a result, the electronic pen 1 of this embodiment has a high moisture-proof function.

[0094] [Second Implementation]

[0095] In the first embodiment described above, as an example of an elastic member that applies force to the pressure detection section side in the axial direction opposite to the pen tip side even when no pen pressure (load) is applied to the front end 5a of the core 5, an O-ring 11 made of elastic rubber is used, utilizing the elastic force of the O-ring 11 to restore the core 5 from an elastically deformed state to its original state. However, the structure of the elastic member is not limited to that of the example described above.

[0096] The second embodiment is an example of another structure having an elastic member that applies force to the core 5 in a way that is opposite to the pressure detection section side in the axial direction to the pen tip side. In the second embodiment, as an example of the structure of the elastic member, a helical spring 14 and an O-ring 15, which will be described later, are used.

[0097] The appearance and overview of the electronic pen 1A in this second embodiment are similar to Figure 1 The electronic pen 1 of the first embodiment shown in (A) is the same. However, in the electronic pen 1A of the second embodiment, the structure for transmitting the pressure applied to the core 5 to the pressure detection unit 9 is different from that of the electronic pen 1 of the first embodiment, but otherwise the same as that of the electronic pen 1 of the first embodiment.

[0098] Figure 4 This is a cross-sectional view showing a structural example of the tip side of the electronic pen 1A according to the second embodiment, and is related to the electronic pen 1 of the first embodiment. Figure 1 The diagram corresponding to (B). In this... Figure 4 In the structure of the electronic pen 1A of the second embodiment, the same reference numerals are used to mark the same structural parts as those of the electronic pen 1 of the first embodiment described above, and detailed descriptions of them are omitted.

[0099] In the electronic pen 1A of the second embodiment, the pen pressure applied to the core 5 is also transmitted to the pressure detection unit 9 via the core support 7A and the pressure transmission member 8A.

[0100] The core holder 7A, like the core holder 7 of the electronic pen 1 in the first embodiment, is made of a conductive material. In this example, it is made of resin mixed with conductive metal powder and has a large diameter portion 7Ab. This large diameter portion 7Ab has a fitting recess 7Aa for fitting the rear end side of the central electrode 51 of the core 5. The exposed portion of the central electrode 51 on the rear end side of the core 5 is pressed into the fitting recess 7Aa of the large diameter portion 7Ab of the core holder 7A, thereby securing the core 5 in the core holder 7A.

[0101] Furthermore, in the electronic pen 1A of the second embodiment, the core support 7A also has a small diameter portion 7Ac on the rear end side of the large diameter portion 7Ab. A helical spring 7Ae made of conductive metal is wound and installed on the other end side of the small diameter portion 7Ac, which is electrically connected to the circuit board 34. The core 5 is electrically connected to the electronic circuit 340 disposed on the circuit board 34 through the helical spring 7Ae.

[0102] The pressure transmission member 8A is made of a non-conductive material, such as resin. In the electronic pen 1A of this second embodiment, it consists of a pressing member 81A and a transmission member support 83A that houses the pressing member 81A in a state that allows it to move along the axial direction. In this second embodiment, the pressing member 82 of the first embodiment is omitted, and pen pressure is transmitted to the pressure detection unit 9 by pressing the pressing member 81A at the front end of the rear end side of the core support 7A.

[0103] Next, the structure for preventing the core 5 in the second embodiment from wobbling in the axial direction and wobbling in a direction orthogonal to the axial direction will be described. Furthermore, the other structures of the electronic pen 1A in the second embodiment are configured similarly to those of the electronic pen 1 in the first embodiment.

[0104] like Figure 4 As shown, in this second embodiment, a cup-shaped component 10A made of resin is provided in the hollow space of the rear end side 6b of the peripheral electrode 6 to ensure electrical insulation between the peripheral electrode 6 and the large diameter portion 7Ab of the core support 7A. The large diameter portion 7Ab of the core support 7A is housed in the recess 10Ab of the cup-shaped component 10A.

[0105] In this case, the large-diameter portion 7Ab of the core support 7A is housed within the recess 10Ab of the cup-shaped member 10A in a state that allows it to move along the axial direction. For example... Figure 4 As shown, at the bottom of the pen tip side of the recess 10Ab of the cup-shaped member 10A, a through hole 10Aa is provided for the rear end side of the central electrode 51 of the core 5 to be inserted. The rear end of the central electrode 51 of the core 5 is pressed into the fitting recess 7Aa of the large diameter portion 7Ab of the core support 7A disposed in the recess 10Ab of the cup-shaped member 10A through the through hole 10Aa. Therefore, the core 5 can move along the axial direction toward the pressure detection unit 9 together with the core support 7A in the internal space of the peripheral electrode 6 and the recess 10Ab of the cup-shaped member 10A. In addition, in this second embodiment, the periphery of the pen tip side end face of the cup-shaped member 10A is disposed in a state of abutting with the step portion 6c inside the peripheral electrode 6, and the cup-shaped member 10A cannot move toward the pen tip side in the axial direction.

[0106] The outer diameter of the cup-shaped component 10A is equal to or slightly smaller than the inner diameter of the rear end side portion 6b of the peripheral electrode 6. Furthermore, the inner diameter of the recess 10Ab of the cup-shaped component 10A is larger than the diameter of the large-diameter portion 7Ab of the core support 7A. In this case, as... Figure 4 As shown, the inner diameter of the recess 10Ab of the cup-shaped member 10A and the outer diameter of the large diameter portion 7Ab of the core support 7A are determined in such a way that a helical spring 14, which forms part of the elastic member, can be disposed between the side peripheral surface of the large diameter portion 7Ab of the core support 7A and the inner peripheral side wall surface of the recess 10Ab of the cup-shaped member 10A.

[0107] Furthermore, in the electronic pen 1A of this second embodiment, an annular protrusion 7Af is provided at the rear end of the large-diameter portion 7Ab (the boundary with the small-diameter portion 7Ac) of the core support 7A, extending orthogonally from the side circumferential surface of the large-diameter portion 7Ab in the axial direction. A helical spring 14 is disposed between the annular protrusion 7Af and the bottom of the recess 10Ab of the cup-shaped member 10A on the pen tip side, always applying force to the core support 7A towards the pressure detection unit 9.

[0108] Moreover, in this second embodiment, such as Figure 4 As shown, an annular end face 83Aa is formed on the pen tip side of the transmission component support 83A, which is opposite to the annular protrusion 7Af of the core support 7A formed by setting the inner wall surface in a stepped shape. An O-ring 15 made of an elastic material, such as elastic rubber, is disposed between the annular end face 83Aa and the annular protrusion 7Af.

[0109] The O-ring 15 serves as part of an elastic member that applies force to the pressure detection unit 9 towards the core support 7A, and also serves to ensure moisture protection within the internal space of the transmission member support 83A by separating the internal space from the external space closer to the pen tip. Furthermore, in this example, the O-ring 15 also suppresses displacement in a direction orthogonal to the axial direction of the core 5 by limiting displacement in a direction orthogonal to the axial direction of the core support 7A. Therefore, the diameter of the O-ring 15 is set to be equal to or slightly larger than the distance between the annular protrusion 7Af of the core support 7A and the annular end face 83Aa of the transmission member support 83A, and is also set to be equal to or slightly larger than the distance between the inner wall surface of the transmission member support 83A and the outer peripheral surface of the core support 7A.

[0110] In this second embodiment, the core support 7A is displaced toward the pressure detection section 9 by the elastic displacement force generated by the helical spring 14, thereby deforming the O-ring 15 in a way that it is elastically flattened. Therefore, the annular protrusion 7Af of the core support 7A and the annular end face 83Aa of the transmission member support 83A are firmly sealed together by the elastic restoring force of the flattened O-ring 15. Combined with the presence of the moisture-proof O-ring 13 provided between the peripheral electrode 6 and the sleeve section 22, moisture-proofing can be ensured to separate the internal space of the transmission member support 83A from the space on the tip side of the electronic pen 1A.

[0111] Furthermore, in this second embodiment, not only the elastic displacement force of the helical spring 14, but also the elastic restoring force of the O-ring 15, which is elastically flattened and displaced, acts as a force that causes the core support 7A to elastically displace towards the pressure detection unit 9. That is, in the second embodiment, the elastic member provided in such a way that it applies force towards the pressure detection unit 9 even when no pressure is applied to the front end 5a of the core 5. Therefore, the suppression effect on the displacement of the core 5 in the axial direction mounted on the core support 7A is greater than that of the electronic pen 1 in the first embodiment.

[0112] According to the second embodiment of the electronic pen 1A, when the state in which the front end 5a of the core 5 is never pressed against the input surface of the position detection device becomes the state in which pen pressure is applied by pressing the front end 5a against the input surface, no initial displacement of the core in the axial direction will occur. This can more reliably prevent the user from feeling so-called wobbling in the axial direction, and can more reliably achieve the same user experience as writing instruments such as pencils and ballpoint pens.

[0113] [Third Implementation Method]

[0114] The third embodiment is a variation of the second embodiment. Figure 5 This is a cross-sectional view showing a structural example of the tip side of the electronic pen 1B according to the third embodiment, and is related to the electronic pen 1A according to the second embodiment. Figure 4 The corresponding diagram. Furthermore, the appearance and outline of the electronic pen 1B in this second embodiment are similar to... Figure 1 The electronic pen 1 of the first embodiment shown in (A) is the same.

[0115] In the electronic pen 1B of the third embodiment, similarly to the electronic pen 1A of the second embodiment, the coil spring 14B and O-ring 16, described later, are used as structural examples of elastic members. In the electronic pen 1A of the second embodiment, the O-ring 15, which also serves to prevent moisture, is located on the rear end side of the coil spring 14. However, in the electronic pen 1B of the third embodiment, the O-ring 16, which also serves to prevent moisture, is located on the tip side of the coil spring 14B, which is different from the second embodiment.

[0116] That is, in the electronic pen 1B of this third embodiment, as Figure 5 As shown, the pressure transmission member 8B, like the pressure transmission member 8A of the electronic pen 1A in the second embodiment, is composed of, for example, a pressing member 81B made of resin and a transmission member support 83B that houses the pressing member 81B in a state capable of moving along the axial direction. Furthermore, the core support 7B in the electronic pen 1B of the third embodiment has the same structure as the core support 7A of the electronic pen 1A in the second embodiment, such as... Figure 5 As shown, it has a large diameter portion 7Bb, which has a fitting recess 7Ba for the exposed portion of the center electrode 51 on the rear end side of the core 5 to be pressed into and fitted, and a small diameter portion 7Bc on the rear end side of the large diameter portion 7Bb, and a pressing member 81B is pressed at the front end of the small diameter portion 7Bc.

[0117] In the electronic pen 1B of this third embodiment, the large-diameter portion 7Bb of the core support 7B is also housed in the recess 10Bb of the cup-shaped member 10B, which has the same structure as the cup-shaped member 10A of the electronic pen 1A of the second embodiment, in a state where it can move along the axial direction. However, in this third embodiment, the cup-shaped member 10B is in a state where it can move along the axial direction within the hollow space of the rear end side portion 6b of the peripheral electrode 6.

[0118] The rear end of the center electrode 51 of the core 5 is pressed into the fitting recess 7Ba of the large diameter portion 7Bb of the core support 7B through a through hole 10Ba provided at the bottom of the recess 10Bb on the pen tip side of the cup-shaped member 10B. In this third embodiment, a helical spring 7Be made of conductive metal is also wound around the small diameter portion 7Bc of the core support 7B, with its other end electrically connected to the circuit board 34, to make electrical connection between the core 5 and the electronic circuit 340 disposed on the circuit board 34.

[0119] Furthermore, the core support 7B has a protruding portion 7Bf that is the same as the protruding portion 7Af of the core support 7A in the second embodiment of the electronic pen 1A. Similar to the electronic pen 1A in the second embodiment, a coil spring 14B is provided between this protruding portion 7Bf and the bottom of the tip side of the recess 10Bb of the cup-shaped member 10B. Through the elastic displacement force of this coil spring 14B, in the electronic pen 1B of the third embodiment, also similar to the electronic pen 1A in the second embodiment, the core support 7A is configured to always apply force towards the pressure detection unit 9.

[0120] Furthermore, in this third embodiment, such as Figure 5As shown, an O-ring 16 made of an elastic material, such as elastic rubber, is disposed between the end face of the tip side of the cup-shaped component 10B and the stepped portion 6c inside the peripheral electrode. This O-ring 16, like the O-ring 11 of the electronic pen 1 of the first embodiment and the O-ring 15 of the electronic pen 1A of the second embodiment, serves as part of an elastic member that applies force to the core support 7B toward the pressure detection portion 9, and also serves to prevent moisture penetration and wobbling in a direction orthogonal to the axial direction of the core 5.

[0121] exist Figure 5 In the example shown, the O-ring 16 is configured to have two O-rings of different diameters arranged concentrically and joined together with their opposing circumferential surfaces. However, the O-ring 16 is not limited to this particular shape and can also be a single O-ring structure.

[0122] In this third embodiment, the cup-shaped component 10B is displaced towards the pen tip side within the hollow space of the rear end side 6b of the peripheral electrode 6 by the elastic displacement force brought by the helical spring 14B, thereby deforming the O-ring 16 in an elastically flattened manner. Therefore, the periphery of the pen tip side end face of the core support 7B and the stepped portion 6c inside the peripheral electrode 6 are firmly sealed by the elastic restoring force of the flattened O-ring 16, ensuring moisture protection by separating the internal space of the transmission member support 83A from the space on the pen tip side of the electronic pen 1B. Furthermore, a moisture-proof O-ring 13 is provided between the outer periphery of the peripheral electrode 6 and the inner wall surface of the sleeve portion 22. Therefore, in the electronic pen 1B of this third embodiment, the O-rings 13 and 16 also shield the internal electrical components of the electronic pen 1B, including the pressure detection unit 9, and the external space on the pen tip side, thus achieving moisture protection for the electronic pen 1B.

[0123] Furthermore, in this third embodiment, not only the elastic displacement force of the helical spring 14B, but also the elastic restoring force of the O-ring 16, which is elastically flattened and displaced, acts as a force that causes the core support 7B to elastically displace towards the pressure detection unit 9. That is, in the third embodiment, the elastic member provided in such a way that it applies force towards the pressure detection unit 9 even when no pressure is applied to the front end 5a of the core 5. Therefore, the suppression effect on the displacement of the core 5 in the axial direction mounted on the core support 7B is greater than that of the electronic pen 1 in the first embodiment.

[0124] In the electronic pen 1B of this third embodiment, the same effect as that of the electronic pen 1A of the second embodiment can also be obtained.

[0125] [Fourth Implementation Method]

[0126] In the electronic pens 1, 1A, and 1B described above, the core supports 7, 7A, and 7B are configured such that even when no pressure is applied to the front end 5a of the core 5, the core supports 7, 7A, and 7B are subjected to force towards the pressure detection unit 9 by elastic members (O-ring 11, coil springs 14 and 15, coil springs 14B, and O-ring 16). That is, by applying a preload to the core supports 7, 7A, and 7B, axial wobbling of the core 5 mounted on the core supports 7, 7A, and 7B is prevented.

[0127] Therefore, in the pressure detection unit 9, even when the pen pressure (load) applied to the core of the electronic pen is zero, the pressure value corresponding to the preload pressure (load) based on the elastic member (hereinafter referred to as the preload value Lpre) is detected. Instead of directly sending the pen pressure value detected by the pressure detection unit 9 (hereinafter referred to as the original pen pressure value Po) to the position detection device equipped with a position detection sensor that accepts writing input from the electronic pen, the electronic pens 1, 1A, and 1B generate a pen pressure output value OP based on the original pen pressure value Po and send it to the position detection device.

[0128] In electronic pens 1, 1A, and 1B, the original pen pressure value Po corresponding to the preload value Lpre of the elastic member is set to a zero offset value OFS. In this example, the zero offset value OFS is set to the same load applied to the pressure detection unit 9 as the preload value Lpre, but it can also be set to a different original pen pressure value Po that is slightly larger than the preload value Lpre.

[0129] Furthermore, when the original pen pressure value Po detected by the pressure detection unit 9 is below the zero offset value OFS, the electronic pens 1, 1A, and 1B output a pen pressure output value OP of zero. Conversely, when the original pen pressure value Po detected by the pressure detection unit 9 is greater than the zero offset value OFS, the electronic pens 1, 1A, and 1B send the value obtained by subtracting the zero offset value OFS from the original pen pressure value Po to the position detection device as the pen pressure output value OP.

[0130] In the position detection device, writing trace information is generated based on the pen pressure output value OP transmitted from electronic pens 1, 1A, and 1B, and the detection output of the indicated position of electronic pens 1, 1A, and 1B. That is, in the position detection device, when the pen pressure output value OP is zero, it is determined that no writing input has been performed, and writing trace information is generated based on the indicated position information detected when the pen pressure output value OP is above zero. Furthermore, in the display device connected to the position detection device, the writing traces input by electronic pens 1, 1A, and 1B are displayed based on this generated writing trace information.

[0131] However, in the electronic pens 1, 1A, and 1B described above, the presence of the elastic member used for preloading also affects the structure for transmitting pressure applied to the front end 5a of the core 5 to the pressure detection unit 9. Therefore, there is no problem when the pressure (load) applied to the front end 5a of the core 5 is small, but after a large pressure (load) is applied to the front end 5a of the core 5, when no pressure is applied to the core 5, the original pen pressure value Po does not return to the zero offset value OFS, and may exhibit a value slightly larger than the zero offset value OFS.

[0132] That is, in the pressure detection unit 9, the original pen pressure value corresponding to the pressure transmitted through the pressing member 81 is detected. However, in this case, if the change characteristics when the pressure increases are exactly the same as the change characteristics when the pressure decreases, the original pen pressure value Po will not return to the zero offset value OFS. However, generally speaking, the change characteristics when the pressure increases and decreases are different, resulting in hysteresis when the pressure increases and decreases. However, if the pressing member 81 is pressed only through the transmission member 82 or the small diameter portions 7Ac and 7Bc of the core support 7A and 7B, the hysteresis is small and can be ignored.

[0133] However, in the electronic pens 1, 1A, and 1B of this embodiment, the elastic member used for preloading participates in the transmission of pressure applied to the front end 5a of the core 5 to the pressure detection unit 9. Therefore, the hysteresis caused by the influence of this elastic member is aggregated, and a hysteresis of a degree that cannot be ignored may occur. Furthermore, compared to the case of the electronic pen 1 of the first embodiment, the probability of this occurring is higher than that of the electronic pen 1A and the electronic pen 1B of the second embodiment, which have a larger number of participating elastic members.

[0134] Figure 6 This diagram illustrates the relationship between the load (pressure) applied to the pressure detection unit 9 and the original pen pressure value Po detected by the pressure detection unit 9. Figure 6 To further explain the aforementioned adverse situations.

[0135] like Figure 6 As shown, in this example, when the load (pressure) applied to the pressure detection unit 9 is the preload value Lpre, the original pen pressure value Po becomes the zero offset value OFS corresponding to the preload value Lpre. At this time, the pen pressure output value OP of electronic pens 1, 1A, and 1B becomes zero.

[0136] Furthermore, when the load applied to the pressure detection unit 9 increases, the original pen pressure value Po also increases accordingly. However, when using a pressure detection element composed of the aforementioned MEMS, such as Figure 6As shown by the solid line, the change characteristic becomes a straight line. Furthermore, when the load applied to the pressure detection unit 9 decreases from a state where a large load has been applied, as... Figure 6 As shown by the dashed line, the original pen pressure value Po decreases depending on the applied load. However, when the load applied to the pressure detection unit 9 becomes the preload value Lpre, the original pen pressure value Po sometimes does not become the zero offset value OFS. In this state, the pen pressure output value OP of electronic pens 1, 1A, and 1B actually becomes zero, but becomes a value greater than zero, which is the state of applied pen pressure.

[0137] That is, even when no pen pressure is applied to the core 5, the original pen pressure value Po does not return to below the zero offset value OFS, but becomes a value slightly larger than the zero offset value OFS. Therefore, the pen pressure output value OP transmitted from the electronic pens 1, 1A, and 1B to the position detection device becomes a value larger than zero even though no pen pressure is applied to the front end 5a of the core 5. On the position detection device side, even if the front end 5a of the core 5 of the electronic pens 1, 1A, and 1B is not actually in contact with the input surface of the position detection sensor and no writing input is performed, it is considered that the front end 5a of the core 5 of the electronic pens 1, 1A, and 1B is in contact with the input surface of the position detection sensor and writing input is performed, resulting in a display image as a writing mark and creating a defective part that is not actually written.

[0138] The fourth embodiment provides an electronic pen that improves upon the aforementioned shortcomings and can be applied to all electronic pens 1, 1A, and 1B described in the first to third embodiments. The electronic pen of this fourth embodiment is characterized by the circuit portion of the electronic circuit 340 that generates the pen pressure output value.

[0139] Figure 7 This diagram illustrates an example of the electronic circuitry 340 in the electronic pen according to the fourth embodiment. It includes a signal transmitting circuit 341, a signal receiving circuit 342, a switching circuit 343, a pen pressure output value transmitting circuit 344, and a control circuit 345. Although not shown in the diagram, the control circuit 345 is composed of a microprocessor equipped with a CPU (Central Control Unit) and memory, functioning as a software processing unit that performs various processes using programs stored in the memory.

[0140] The signal transmitting circuit 341 has an oscillation circuit with a predetermined frequency. Under the control of the control circuit 345, it generates a position detection signal, which is supplied to the center electrode 51 of the core 5 via the switching circuit 343 and transmitted to the position detection sensor via electrostatic coupling with the center electrode 51. The position detection signal is transmitted as a pulse train signal of a predetermined frequency.

[0141] Peripheral electrode 6 receives signals from the position detection sensor via electrostatic coupling. For example... Figure 7 As shown, the signal received from the position detection sensor by the peripheral electrode 6 is supplied to the control circuit 345 through the signal receiving circuit 342. The control circuit 345 controls the output timing of the signal from the signal transmitting circuit 341 based on the timing of the signal received from the position detection sensor, and controls the switching circuit 103 to switch.

[0142] In this example, the control circuit 345 is connected to a variable capacitance capacitor 9C, which is composed of a pressure detection unit 9. The control circuit 345 includes a pen pressure output value generation circuit 3451 that detects the initial pen pressure value Po based on the electrostatic capacitance of the variable capacitance capacitor 9C and generates a pen pressure output value OP based on the detected initial pen pressure value Po. In this example, the pen pressure output value generation circuit 3451 is configured as a software function that generates the pen pressure output value OP by executing a program stored in memory. The operation of this pen pressure output value generation circuit 3451 will be described in detail later.

[0143] The pen pressure output value OP generated by the pen pressure output value generation circuit 3451 of the control circuit 345 is supplied to the pen pressure output value transmission processing circuit 344. The pen pressure output value OP from the pen pressure output value generation circuit 3451 is, for example, a 12-bit binary digital signal. The pen pressure output value transmission processing circuit 344 performs transmission processing such as ASK (Amplitude Shift Keying) modulation, PSK (Phase Shift Keying) modulation, or OOK (On Off Keying) modulation to transmit the binary digital signal to the position detection sensor through the center electrode 51 of the core 5. The pen pressure output value OP, which has thus undergone transmission processing, is transmitted to the position detection sensor through the switching circuit 343 and the center electrode 51 of the core 5.

[0144] In this example, the control circuit 345 switches the control switch circuit 343 to transmit the position detection signal (pulse train signal) from the signal transmission circuit 341 and the pen pressure output value OP, which has undergone transmission processing, from the pen pressure output value transmission processing circuit 344 in a time-division manner through the center electrode 51 of the core 5 to the position detection sensor. Furthermore, the position detection signal is not limited to a pulse train signal; it can also be a PSK-modulated signal.

[0145] Next, the operation of the pen pressure output value generation circuit 3451 will be explained. The pen pressure output value generation circuit 3451 determines the first threshold θf1 (refer to a reference value) where the detected raw pen pressure value Po is less than the estimated hysteresis caused by the influence of the elastic member. Figure 6Within a small range, the pen pressure output value OP is directly sent out. The first threshold θf1 is used to determine whether the original pen pressure value Po increases to a level that prevents it from returning to the zero offset value OFS when no more pen pressure is applied to the core 5. In this example, the first threshold θf1 is set to a value slightly larger than the zero offset value when the original pen pressure value Po does not return to the zero offset value OFS when no more pen pressure is applied to the core 5.

[0146] Furthermore, when the detected original pen pressure value Po becomes larger than the aforementioned predetermined threshold θf1 and the hysteresis caused by the elastic member increases, the pen pressure output value generation circuit 3451 establishes a flag FLG (set to FLG = "1") to identify its state. And, while this flag FLG is set (FLG = "1"), when the original pen pressure value Po becomes larger than the predetermined return threshold θre (refer to... Figure 6 When the value is small, the pen pressure output value OP is forcibly set to zero. This improves the situation where the pen pressure output value OP is greater than zero even though no pen pressure (load) is applied to the front end 5a of the core 5.

[0147] In this case, the return threshold θre can be set to a predetermined constant value, but in this example, it is dynamically determined based on the maximum value of the past original pen pressure values. That is, in this example, the pen pressure output value generation circuit 3451 detects the original pen pressure value Po every few milliseconds, for example, based on the electrostatic capacitance of the variable capacitance capacitor 9C, but determines the return threshold θre based on the maximum value of the past 100 original pen pressure values ​​Po. For example, if 100 detected original pen pressure values ​​Po are stored, the return threshold θre is determined by repeatedly performing this process on every 100 detected original pen pressure values ​​Po, based on the maximum value among them.

[0148] In this example, the flag FLG (FLG = "1") is set such that the detected raw pen pressure value Po becomes a second threshold θf2 that is equal to or less than the pen pressure output value OP = 0, i.e., the zero offset value OFS (see reference). Figure 6 When the value is below 0, the flag FLG returns to its original state (FLG = "0").

[0149] Next, refer to Figure 8 and Figure 9 The flowchart shown illustrates the operation of the pen pressure output value generation circuit 3451. Furthermore, the following description assumes that the control circuit 345 performs the operation. Figure 7 and Figure 8 The steps will be explained in detail.

[0150] The control circuit 345, for example, monitors the received signal of the signal receiving circuit 342 and determines whether it is in a state of being connected with the position detection sensor (step S101). If it is determined that it is not in a state of being connected, it continues with step S101.

[0151] In step S101, when it is determined that the system is in a state of connection with the position detection sensor, the control circuit 345 detects the original pen pressure value Po based on the electrostatic capacitance 9C of the pressure detection unit 9 (step S102), and determines whether the detected original pen pressure value Po is below the zero offset value OFS (Po≤OFS) (step S103).

[0152] In step S103, when it is determined that the detected original pen pressure value Po is below the zero offset value OFS, the control circuit 345 outputs zero (OP = 0) as the pen pressure output value OP (step S104).

[0153] Next, the control circuit 345 determines whether it is the next detection timing for the original pen pressure value Po (step S105). If it is determined that it is not the next detection timing, it determines whether the connection with the position detection sensor has been released (step S106). Then, if it is determined in step S106 that the connection with the position detection sensor has not been released, the control circuit 345 returns the process to step S105 and repeats the steps after step S105. Alternatively, if it is determined in step S106 that the connection with the position detection sensor has been released, the control circuit 345 terminates the processing routine.

[0154] Furthermore, in step S105, when it is determined that the next detection timing has become the original pen pressure value Po, the control circuit 345 causes the processing to return to step S102 and repeats step S102.

[0155] If, in step S103, it is determined that the detected original pen pressure value Po is not below the zero offset value OFS but is greater than the zero offset value OFS, the control circuit 345 determines whether the original pen pressure value Po increases or decreases (step S107). If, in step S107, it is determined that the original pen pressure value Po increases, the control circuit 345 determines whether the original pen pressure value Po is greater than the first threshold θf1 (Po > θf1) (step S108).

[0156] In step S108, if it is determined that the original pen pressure value Po is greater than the first threshold θf1, the control circuit 345 establishes the flag FLG (set to FLG = "1") (step S109). Then, the pen pressure output value OP is generated and output according to the original pen pressure value Po (step S110).

[0157] Furthermore, if in step S108 it is determined that the original pen pressure value Po is below the first threshold θf1, the control circuit 345 bypasses step S109, does not perform processing regarding the flag FLG, and proceeds to step S110, generating and outputting the pen pressure output value OP based on the original pen pressure value Po. After step S110, the control circuit 345 proceeds to step S105, determines whether it has become the next detection timing for the original pen pressure value Po, and performs the aforementioned processing after step S105 based on the determination result.

[0158] Furthermore, in step S107, when it is determined that the original pen pressure value Po has decreased, the control circuit 345 determines whether the flag FLG is set (whether FLG = "1" is true). Figure 9 Step S111). In this step S111, when it is determined that the flag FLG is not set (FLG = "0"), the control circuit 345 directly outputs the generated pen pressure output value OP (step S112). Then, the control circuit 345 causes the processing to enter... Figure 8 Step S105, the subsequent processing.

[0159] Furthermore, in step S111, when it is determined that the flag FLG is set (FLG = "1"), the control circuit 345 determines whether the original pen pressure value Po is below the return threshold θre (Po ≤ θre) (step S113). In this step S113, if it is determined that the original pen pressure value Po is not below the return threshold θre but is greater than the return threshold θre, the control circuit 345 causes the processing to proceed to step S112, directly outputting the pen pressure output value OP generated based on the original pen pressure value Po, and then causes the processing to proceed to... Figure 8 Step S105, the subsequent processing.

[0160] Furthermore, in step S113, when it is determined that the original pen pressure value Po is below the return threshold θre, the control circuit 345 forcibly outputs the pen pressure output value OP as zero (OP = 0) regardless of the detected original pen pressure value Po (step S114). Also, the control circuit 345 determines whether the detected original pen pressure value Po is below the second threshold θf2 (step S115), and if it is determined that it is not below the second threshold θf2, it initiates further processing. Figure 8 Step S105, the subsequent processing.

[0161] Additionally, in step S115, when it is determined that the detected original pen pressure value Po is below the second threshold θf2, the control circuit 345 resets the flag FLG (sets FLG = "0") (step S116). Then, the control circuit 345 initiates processing. Figure 8Step S105, the subsequent processing.

[0162] As described above, the electronic pen according to the fourth embodiment can improve the situation where the original pen pressure value Po does not return to the zero offset value OFS and outputs a pen pressure output value OP that is larger than zero when no more pen pressure is applied to the core 5.

[0163] It should be noted that in the description of the electronic pen in the fourth embodiment above, the pen pressure output value OP is transmitted to the position detection sensor via electrostatic coupling through the central electrode 51 of the core 5 in a time-division manner, together with the position detection signal. However, the structure for transmitting the pen pressure output value OP to the position detection device is not limited to this. For example, the peripheral electrode 6 can be configured to serve as both a receiver and a transmitter, with the position detection signal transmitted through the central electrode 51 of the core 5 and the pen pressure output value OP transmitted through the peripheral electrode 6. Alternatively, a wireless communication unit can be provided in the electronic pen and the position detection device, through which the pen pressure output value OP is transmitted.

[0164] In addition, in the fourth embodiment described above, the electronic pens 1, 1A, and 1B generate a pen pressure output value OP from the pen pressure output value generation circuit 3451 of the control circuit 345 based on the original pen pressure value Po, and send the generated pen pressure output value OP to the position detection device. However, the electronic pens 1, 1A, and 1B may also be configured to send the original pen pressure value to the position detection device, and a pen pressure output value generation circuit that performs the same operation as the pen pressure output value generation circuit 3451 may be provided on the position detection device.

[0165] [Other implementation methods or variations]

[0166] The core supports 7, 7A, and 7B are not limited to the core supports made of conductive resin mixed with conductive metal as described above. For example, the core supports 7, 7A, and 7B may also be made of resin made of insulating material, with a conductive member provided at the fitting portion of the central electrode 51 of the core 5, and the conductive member of the fitting portion electrically connected to the circuit board by a conductive helical spring of the same type as in the example described above.

[0167] Furthermore, the first pressure transmission member 8 is not limited to being divided into two parts as in the example above: a pressing member 81 and a pressing component 82 that pushes the pressing member 81 toward the axial direction. For example, the pressure transmission member 8 may also be a single pressure transmission member structure that integrally includes the fitting part of the core support 7 and the pressing protrusion 9a of the pressing pressure detection part 9.

[0168] Furthermore, in the electronic pen 1 of the first embodiment described above, an O-ring 11, as an example of an elastic member, is disposed between the annular end face of the core support 7 on the tip side and the wall portion (the wall portion of the bottom surface of the recess 10b) of the cup-shaped member 10 having a through hole 10a. The cup-shaped member 10 is fitted and locked inside the peripheral electrode 6 locked within the pen housing 2. However, this is just an example. In the electronic pen 1 of the above embodiment, the O-ring 11, as an example of an elastic member, only needs to be disposed between the annular end face of the core support 7 on the tip side and the wall portion within the pen housing 2 that does not move in the axial direction but is orthogonal to the axial direction.

[0169] Furthermore, the elastic member used to apply force to the pressure detection section 9 of the core 5 is not limited to O-rings or coil springs. Any elastic member that can apply force to the pressure detection section 9 of the core 5 using a force that elastically recovers from an elastically deformed state to its original state is acceptable. In this case, the elastic member used to apply force to the pressure detection section 9 of the core 5 is preferably also capable of suppressing displacement in a direction orthogonal to the axial direction of the core 5.

[0170] Furthermore, the electronic pens 1, 1A, and 1B described in the above embodiments are examples of active electrostatic capacitive electronic pens. However, the present invention is not limited to active electrostatic capacitive pens and can be applied to all electronic pens that have a pressure detection unit that detects the pressure applied to the front end of the core.

[0171] Figure 10 This diagram shows the main part of the tip side of the electronic pen 1D, which utilizes the electromagnetic induction method of the present invention. Figure 10 As shown, in this example of the electronic pen 1D, an electromagnetic induction-based main body unit 3D is disposed within the hollow space of the pen casing 2D. Furthermore, in this... Figure 10 In the example of the electronic pen 1D, the same components as those in the electronic pen 1 of the above-described embodiment are shown with the suffix "D" appended to the same numbers.

[0172] In this example of the electronic pen 1D, a pen tip-side component 32D is provided on the pen tip side of the boat-shaped unit support 31D of the main body unit 3D. For example... Figure 10 As shown, the pen tip side component 32D has a magnetic core with a coil 101 wound around it. In this example, it has a ferrite core 102, a pressure transmission member 8D, and a pressure detection unit 9D.

[0173] In the electronic pen 1D of this example, a through hole 102a in the ferrite core 102 is provided in the axial direction. Furthermore, as... Figure 10As shown, the core 103 of the electronic pen 1D in this example has a front end portion 103a protruding outward from the opening 2Da on the tip side of the pen shell 2D, and an elongated rod-shaped core body portion 103b integrally provided on the rear end side of the front end portion 103a with a diameter smaller than the maximum diameter of the front end portion 103a. The core 103 is made of resin, for example. The diameter of the core body portion 103b of the core 103 is smaller than the through hole 102a of the ferrite core 102, and the axial length of the core body portion 103b is selected to be longer than the axial length of the ferrite core 102. Therefore, the core body portion 103b of the core 103 is inserted through the through hole 102a of the ferrite core 102, such as... Figure 10 As shown, it protrudes towards the rear end of the ferrite core 102. Furthermore, the rear end of the protruding core body portion 103b of the core 103 engages with the pressure transmission member 8D and moves integrally with the pressure transmission member 8D in the axial direction.

[0174] The pressure detection unit 9D, like the pressure detection unit 9 of the electronic pen 1 in the above embodiment, is configured to use a semiconductor device structure that detects the pressure applied to the pressure-bearing protrusion 9Da by means of changes in electrostatic capacitance. Furthermore, similar to the electronic pen 1 in the above embodiment, the pressure detection unit 9D is housed and held in the housing recess 91Da of the pressure detection unit bracket 91D, and the pressure detection unit bracket 91D is housed and held in the pressure detection unit bracket housing portion 310D provided on the pen tip side of the unit bracket 31D.

[0175] In this example, the pressure transmission member 8D is made of resin, and the pressing part 81D of the pressure-receiving protrusion 9Da of the pressure detection part 9D and the pressing part 82D are integrally formed. Moreover, the pressure transmission member 8D is housed in the hollow space of the cylindrical transmission member support 83D held in the pressure detection part support storage part 310D of the unit support 31D in a state that allows it to move along the axial direction.

[0176] In its retracted state within the hollow space of the transmission member bracket 83D, the pressing part 81D of the pressure transmission member 8D is configured to insert through the through hole 83Da of the transmission member bracket 83D and the through hole 91Db of the pressure detection part bracket 91D, and press the pressure-receiving protrusion 9Da of the pressure detection part 9D. A fitting recess 82Da is formed on the tip side of the pressing part 82D for the rear end of the core body part 103b of the core 103 to fit into.

[0177] Furthermore, in the electronic pen 1D of this example, such as Figure 10 As shown, a cylindrical ferrite core holder 84 is provided on the tip side of the transmission component support 83D, and the rear end of the ferrite core 102 is fitted into the hollow portion of the ferrite core holder 84. Thus, in this... Figure 10In the example of the electronic pen 1D, a ferrite core 102 configured to have a coil 101 wound around it is held on the pen tip side of the transmission member support 83D.

[0178] In this case, such as Figure 10 As shown, an annular protrusion 84a, orthogonal to the axial direction, is formed on the inner wall surface of the hollow portion of the cylindrical ferrite core holder 84. The height of this annular protrusion 84a (its length in the direction orthogonal to the axial direction) is set to a value that will not contact the rear end side of the core body portion 103b of the core body 103 through which the ferrite core 102 is inserted. Figure 10 As shown, the ferrite core 102 is held by the ferrite core holding part 84 with its rear end face abutting against the annular protrusion 84a.

[0179] And, as Figure 10 As shown, in the hollow space of the ferrite core holding part 84, on the pen tip side of the pressing member part 82D that accommodates the pressure transmission member 8D at the rear end of the annular protrusion 84a, the rear end of the core body part 103b of the core 103 is fitted in the fitting recess 82Da formed in the pressing member part 82D.

[0180] At this time, a predetermined gap is formed between the annular end face 82Dt surrounding the fitting recess 82Da on the end face of the pressing member 82D on the tip side of the pressure transmission member 8D and the annular end face of the annular protrusion 84a of the ferrite core holding part 84 in a direction orthogonal to the axial direction. In the electronic pen 1D of this example, as Figure 10 As shown, an O-ring 11D with a circular cross-section and a diameter slightly larger than the size of the gap is disposed in the gap. Therefore, the O-ring 11D is disposed in a state of elastic compression and elastic deformation, at least in the axial direction.

[0181] In this example of the electronic pen 1D, the ferrite core holding portion 84 is positioned so that it does not move towards the tip in the axial direction within the pen casing 2D. Therefore, due to the elastic restoring force of the elastically deformed O-ring 11D to its original state, the pressure transmission member 8D is always subjected to force towards the pressure detection portion 9D in the axial direction. Consequently, the core 103, which is fitted with the pressure transmission member 8D, is also always subjected to force towards the pressure detection portion 9D in the axial direction when no pressure is applied to its front end 103a. Figure 10 In the example, the protrusion 84a of the ferrite core retaining part 84 forms a wall portion within the pen case 2D that cannot move toward the pen tip side in the axial direction.

[0182] In addition, in Figure 10In the example electronic pen 1D, the outer diameter of the O-ring 11D is selected to be equal to or slightly larger than the inner diameter of the hollow portion on the rear end side of the ferrite core holder 84. However, in this example, the diameter of the inner circumference of the O-ring 11D is set to a diameter that does not contact the rear end of the central electrode 51 of the core 5.

[0183] Therefore, the O-ring 11D is in contact with the wall portion of the hollow portion in the axial direction of the ferrite core holding portion 84, which is located further back than the annular protrusion 84a. Thus, when the O-ring 11D is elastically compressed and elastically deformed in the axial direction, it elastically deforms by slightly elongating in a direction orthogonal to the axial direction. That is, an elastic offset force acting towards the center of the O-ring 11D acts on the O-ring 11D. This elastic offset force towards the center of the O-ring 11D becomes a force that suppresses the displacement (wobbling in a direction orthogonal to the axial direction) of the pressure transmission member 8D in the direction orthogonal to the axial direction.

[0184] As mentioned above, in this Figure 10 In the example electronic pen 1D, the core 103 is always in a state where force is applied towards the pressure detection unit 9D in the axial direction, even when no pressure is applied to the front end 103a. Therefore, even when the front end 103a of the core 103 is never pressed against the input surface of the position detection device, and pen pressure is applied by pressing the front end 103a against the input surface, no initial displacement in the axial direction of the core occurs, preventing the user from feeling so-called wobbling in the axial direction. Therefore, the electronic pen 1D according to this embodiment can achieve the same user experience as writing instruments such as pencils and ballpoint pens.

[0185] In addition, in Figure 10 In the example electronic pen 1D, the displacement of the pressure transmission member 8D in the direction orthogonal to the axial direction is also suppressed by the elastic offset force of the compressed O-ring 11D. Therefore, the displacement (wobbling) of the core 103 that is fitted with the pressure transmission member 8D in the direction orthogonal to the axial direction is also suppressed.

[0186] Moreover, in Figure 10 In the example electronic pen 1D, a cap member 104, made of an elastic member, is covered on the tip side of the ferrite core 102 by an outer peripheral surface having an inner wall surface of a tapered portion along the tip side of the pen shell 2D. For example... Figure 10 As shown, the cap component 104 has a through hole of a size larger than the diameter of the through hole 102a of the ferrite core 102 so that the rear end of the core body 103b of the core 103 can be inserted.

[0187] Furthermore, in the electronic pen 1D of this example, such as Figure 10As shown, the cap member 104 on the tip side of the ferrite core 102 is configured to elastically press against the inner wall surface of the cone portion on the tip side of the pen casing 2D, thereby ensuring that the outer peripheral surface of the cap member 104 is tightly fitted against the inner wall surface of the cone portion on the tip side of the pen casing 2D without any gap. In other words, the cap member 104 has the function of separating the space communicating with the outside through the opening 2Da of the pen casing 2D on the tip side of the ferrite core 102, and the hollow space within the pen casing 2D that houses the ferrite core 102 and the main body unit 3D.

[0188] Furthermore, in the electronic pen 1D of this example, as can be seen from the above structure, the O-ring 11D also has the function of separating the moving space of the pressure transmission member 8D in the transmission member support 83 from the external space that is connected to the through hole 102a of the ferrite core 102 and the space of the pen tip side of the pen shell 2D.

[0189] Therefore, in Figure 10 In the example of the electronic pen 1D, the external space connected by the O-ring 11D and the cap component 104 through the opening on the tip side of the electronic pen 1D is separated from the space in the hollow space of the pen shell 2D that contains the main body unit 3D, and the electronic pen 1D has a moisture-proof structure.

[0190] In addition, in the above Figure 10 In the example electronic pen 1D, the ferrite core 102 is held by a ferrite core holding part 84, and a wall portion (in a direction orthogonal to the axial direction) is provided in the ferrite core holding part 84. Figure 10 In the example of the protrusion 84a), an O-ring 11D, as an example of an elastic member, is provided between the wall portion and the end face of the pressure transmission member 8D of the fitting core 103. However, the end face of the rear end side of the ferrite core 102 can form a wall portion orthogonal to the axial direction, so an O-ring 11D, as an example of an elastic member, can also be provided between the end face of the rear end side of the ferrite core 102 and the end face of the pressure transmission member 8D.

[0191] In addition, Figure 10 In the example of the electronic pen 1D, there is no structure in which the coil spring, which serves as a shock absorber, is provided at the rear end of the pressure detection unit 9D. However, similar to the electronic pen 1, it is possible to provide a structure in which the coil spring, which serves as a shock absorber, is provided at the rear end of the pressure detection unit 9D.

[0192] [Other implementation methods or variations]

[0193] Furthermore, in the electronic pens 1, 1A, 1B, and 1D described above, the pressure detection unit uses a structure comprised of a semiconductor device whose distance between two electrodes facing each other, separated by an air layer that acts as a dielectric, varies according to the applied pressure (see Patent Document 2 mentioned above). However, this is not the only possibility. For example, a pressure detection unit with a structure where the contact area between the dielectric and the conductive elastic member changes according to the applied pressure, thereby changing the electrostatic capacitance (see Patent Document 1 mentioned above) could also be used.

[0194] Furthermore, the pressure detection unit (pen pressure detection unit) 9 is not limited to a capacitive sensor that detects pressure (pen pressure) based on capacitance changes in the above-described embodiment. It can also use an inductive sensor that detects pressure (pen pressure) based on inductance changes, or a resistive sensor that detects pressure (pen pressure) based on resistance changes, etc.

[0195] Explanation of reference numerals in the attached figures

[0196] 1, 1A…Electronic pen, 2, 2A…Pen shell, 3, 3A…Main body unit, 5…Core, 6…Peripheral electrode, 7…Core support, 7t…Annular end face, 8, 8A…Pressure transmission component, 9, 9A…Pressure detection part, 10…Cup-shaped component, 11, 12, 13…O-ring, 31, 31A…Unit support, 32, 32A…Pen tip side component, 34…Circuit board, 51…Center electrode, 52…Protective component, 101…Coil, 102…Ferrite core, 103…Core, 104…Cap component.

Claims

1. An electronic pen, characterized in that, have: The pen casing is cylindrical with an opening on the nib side; The core is assembled with its front end protruding from the opening on the tip side toward the outside of the pen casing; A pressure detection unit is disposed inside the hollow portion of the pen casing on the side opposite to the front end of the core in the axial direction, for detecting the pressure applied to the front end of the core; as well as The elastic member is configured to exert force on the core in the hollow portion of the pen casing in the opposite direction to the axial direction of the pen tip side, even when no pressure is applied to the front end.

2. The electronic pen according to claim 1, characterized in that, The elastic member is configured to exert force on the core in the hollow portion of the pen casing toward the side opposite to the pen tip in the axial direction, even when no pressure is applied to the front end, by means of a restoring force from the elastically deformed state to the original state.

3. The electronic pen according to claim 1, characterized in that, The elastic member is also configured to suppress displacement of the core in a direction orthogonal to the axial direction.

4. The electronic pen according to claim 1, characterized in that, It has a pressure transmission member for fitting into the rear end of the core on the side opposite to the front end in the axial direction. The pressure applied to the front end of the core is transmitted to the pressure detection unit via the pressure transmission member. The elastic member is configured to apply force to the pressure transmission member of the rear end of the core in the axial direction opposite to the tip side.

5. The electronic pen according to claim 4, characterized in that, The pressure transmission member has a fitting recess for fitting the rear end of the core, and has an annular end face around the fitting recess with a surface direction intersecting the axial direction of the pen shell. The elastic member is configured to apply force to the annular end face on the side opposite to the pen tip side in the axial direction.

6. The electronic pen according to claim 5, characterized in that, The pen has a wall portion that is spaced at a predetermined interval from the annular end face of the pressure transmission member in the axial direction, and is positioned within the pen casing so that it cannot move towards the pen tip in the axial direction. The elastic member is positioned between the annular end face and the wall portion in a state of elastic deformation.

7. The electronic pen according to claim 6, characterized in that, The wall portion has a through hole through which the rear end of the core is inserted. The elastic member is disposed around the through hole in the wall and between the annular end face of the pressure transmission member.

8. The electronic pen according to claim 7, characterized in that, The elastic member is an O-ring.

9. The electronic pen according to claim 5, characterized in that, The pen includes a pressure transmission component support, which is disposed within the pen housing in a fixed axial direction, and, when the pressure transmission component is movable in the axial direction, at least the fitting side of the core of the pressure transmission component is accommodated. The pressure transmission component support has a wall portion that is positioned opposite the annular end face of the pressure transmission component at a predetermined interval in the axial direction, and has a through hole for the rear end of the core to be inserted. The elastic member is disposed around the through hole in the wall and between the annular end face of the pressure transmission member.

10. The electronic pen according to claim 9, characterized in that, The elastic member is an O-ring.

11. The electronic pen according to claim 1, characterized in that, The pen casing includes a sealing member made of an elastomer, disposed between the inner wall surface of the pen casing and the outer peripheral surface of a component within the pen casing. This sealing member is configured to separate a space within the hollow portion of the pen casing containing the pressure sensing element from a space within the hollow portion of the pen casing that communicates with an external space protruding from the front end of the core. The elastic member is configured to separate the space within the hollow portion of the pen case where the pressure detection unit is located from the space within the hollow portion of the pen case that communicates with the external space protruding from the front end of the core.

12. The electronic pen according to claim 1, characterized in that, The core support is provided for fitting the rear end of the core. The pressure applied to the front end of the core is transmitted to the pressure detection unit via the core support. The elastic member is configured to apply force to the core support, which is fitted with the rear end portion of the core, in a direction opposite to that of the pen tip in the axial direction.

13. The electronic pen according to claim 12, characterized in that, The core and the core support are made of conductive components. The electronic pen uses an active electrostatic capacitor to transmit signals from the signal transmission circuit via the core support and the core.

14. The electronic pen according to claim 12, characterized in that, A pressure transmission component is provided between the core support and the pressure detection unit. The pressure applied to the front end of the core is transmitted to the pressure detection unit via the core support and the pressure transmission member.

15. The electronic pen according to claim 12, characterized in that, The core support has a fitting recess for fitting the rear end of the core, and around the fitting recess is an annular end face with a surface direction intersecting the axial direction of the pen shell. The elastic member is configured to apply force to the annular end face on the side opposite to the pen tip side in the axial direction.

16. The electronic pen according to claim 15, characterized in that, It has a wall portion that is positioned opposite the annular end face of the core support at a predetermined interval in the axial direction, and is fixed within the pen casing in a state where it cannot move in the axial direction. The elastic member is positioned between the annular end face and the wall in an elastically deformed state.

17. The electronic pen according to claim 16, characterized in that, The wall portion has a through hole through which the rear end of the core is inserted. The elastic member is disposed around the through hole in the wall and between the annular end face of the core support.

18. The electronic pen according to claim 17, characterized in that, The elastic member is an O-ring.

19. The electronic pen according to claim 15, characterized in that, The core and the core support are made of conductive components. The device includes a peripheral electrode disposed on one side of the rear end portion of the core, and an insulating member disposed between the peripheral electrode and the core support. The insulating member is disposed within the pen casing in a state in which it cannot move in the axial direction, and is disposed such that at least the fitting portion of the core support that is fitted with the rear end portion of the core can be accommodated in a state in which the core support can move in the axial direction. The insulating member has a wall portion that is positioned opposite the annular end face of the core support at a predetermined interval in the axial direction, and has a through hole for the rear end of the core to be inserted. The elastic member is disposed around the through hole in the wall and between the annular end face of the core support.

20. The electronic pen according to claim 19, characterized in that, The elastic member is an O-ring.

21. The electronic pen according to claim 1, characterized in that, The electronic pen uses electromagnetic induction and has a magnetic core with a through hole for insertion at the rear end of the core and a coil wound around it.

22. The electronic pen according to claim 1, characterized in that, The elastic component consists of a helical spring and an O-ring.

23. The electronic pen according to claim 1, characterized in that, A pen pressure output value generation circuit is provided that generates a pen pressure output value based on the raw pen pressure value detected by the pressure detection unit. The pen pressure output value generation circuit outputs zero as the pen pressure output value when the original pen pressure value becomes greater than a first predetermined value and then becomes less than a second predetermined value.

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