JP2019016038A - Force receiving member, force detection sensor, and electronic pen - Google Patents

Abstract

To provide a force receiving member capable of enhancing durability against an applied force.SOLUTION: A force receiving member of a force detection sensor which detects an applied force from an electric variation detected on the basis of a displacement occurring according to the received force, includes a rod-like section whose one end in an axial direction is at a position for receiving the force, and a braking section. The braking section has a cylindrical shape, and in the hollow section of the cylindrical shape, the rod-like section is partially accommodated. An inner wall surface of the cylindrical-shaped braking section is couped with an outer peripheral surface on the one end side in the axial direction of the rod-like section, and is spatially apart from an outer peripheral surface of the rod-like section on the other end side different from the one end in the axial direction of the rod-like section. A displacement occurring by the received force in a state in which the other end side of the rod-like section is locked, of the braking section is detected by the force detection sensor provided at the other end side of the rod-like section rather than the coupling position of the rod-like section and the braking section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a force receiving member in a force detection sensor that detects a received force based on detecting a displacement such as a strain generated according to the received force. The present invention also relates to a force detection sensor that detects an external force received by the force receiving member. Furthermore, the present invention relates to an electronic pen that uses this force detection sensor to detect a force component of a writing pressure (force component in the Z-axis direction) applied in the axial direction to the core of the electronic pen, for example.

  Many electronic pens have a pressure sensor for detecting contact with an input surface of a position detection sensor and pressure (writing pressure) at the time of contact. As a configuration of the pressure sensor, a dielectric capacitor is mechanically sandwiched between two electrodes, and a capacitance variable capacitor (see Patent Document 1) having a configuration in which the capacitance between the two electrodes changes according to the writing pressure, or a semiconductor device is used. A configured variable capacitor (see Patent Document 2) or the like is often used, but the use of a strain gauge has also been proposed (see Patent Document 3 and Patent Document 4).

  A strain gauge is a mechanical sensor (force detection sensor) for measuring strain of an object, and a semiconductor strain gauge is often used in an electronic pen. Semiconductor strain gauges are strain gauges that use the piezoresistive effect, in which the electrical resistivity of a semiconductor changes with stress, and the piezoelectric effect, in which polarization (surface charge) is proportional to the applied pressure. is there.

  A so-called triaxial force detection sensor has also been proposed as a pressure sensor using a strain gauge, and it is conceivable to use this triaxial force detection sensor mainly in an electronic pen (see Patent Documents 5 and 6). . When this triaxial force detection sensor using a strain gauge is used for an electronic pen, not only the pressure (writing pressure) in the axial direction of the electronic pen perpendicular to the input surface of the position detection sensor but also the input of the position detection sensor Even when the electronic pen is inclined at a predetermined angle with respect to the surface, the force applied to the pen tip of the electronic pen can be detected, and the inclination angle of the electronic pen with respect to the input surface of the position detection sensor is also detected. It can be convenient.

JP 2011-186803 A JP 2013-161307 A US Pat. No. 5,548,092 US Patent No. 9322732 JP 2010-164495 A U.S. Pat. No. 4,896,543

  By the way, as a force detection sensor which detects the external force applied to the core of an electronic pen using a strain gauge, it can comprise with what used the above-mentioned triaxial force detection sensor of patent document 5. FIG. FIG. 16A is a front view of an example of this type of force detection sensor as viewed from a direction orthogonal to the Z-axis direction, which is an application direction of external force such as writing pressure of an electronic pen. The force receiving unit 102 is integrally coupled to the strain generating unit 101.

  The force receiving unit 102 has a function of receiving an applied force and transmitting the applied force to the strain generating unit 101 at the distal end opposite to the side coupled to the strain generating unit 101. In the case of an electronic pen, the force receiving unit 102 is a core of the electronic pen itself or a rod-like member to which the core is fitted. FIG. 16B is a longitudinal sectional view (a sectional view in a direction including the Z-axis direction) of the force detection sensor of this example, and FIG. 16C is a perspective view thereof. 16B to 16E, for the sake of convenience, the force receiving unit 102 is shown only in the vicinity of the strain generating unit 101.

  As shown in FIGS. 16 (B) and 16 (C), the strain generating portion 101 is such that a thin disk-like diaphragm 101a is provided on one opening side of the cylindrical diaphragm holding portion 101b. It has a structure. And it is couple | bonded with the rod-shaped force reception part 102 in the center part of the disk-shaped diaphragm 101a.

  A strain gauge 103 is attached to the surface of the diaphragm 101a opposite to the side where the force receiving portion 102 is coupled. The strain gauge 103 is formed by arranging a plurality of strain sensing elements (not shown) on a flexible substrate 103a made of, for example, a disk-shaped insulating film sheet.

  In the triaxial force detection sensor of this example, when a force (writing pressure) in the Z-axis direction is applied to the strain generating unit 101 via the force receiving unit 102, the diaphragm 101a of the strain generating unit 101 has a tensile force. -A compressive stress is added and it curves so that it may become convex below according to the displacement of the Z-axis direction of the force reception part 102, as shown in FIG.16 (D). The strain gauge 103 is displaced according to the curvature of the diaphragm 101a, and is extended and displaced as indicated by an arrow in FIG. For this reason, the strain-sensitive element disposed on the flexible substrate 103a of the strain gauge 103 is similarly displaced, and its resistance value changes. By detecting the change, the Z-axis direction is detected. Force (writing pressure) can be detected.

  In this case, in the case of the triaxial force detection sensor of this example, a force component in the X axis direction or the Y axis direction orthogonal to the Z axis direction is also applied to the core body. The force component in the X-axis direction or the Y-axis direction acts as a bending moment corresponding to the length of the force receiving unit 102, and bending stress and shear stress are applied to the diaphragm 101a of the strain generating unit 101. Therefore, in the diaphragm 101a, as shown in FIG. 16E, the diaphragm 1012a contracts in front of the coupling portion with the force receiving portion 102 in the direction of applying the force in the X-axis direction or the Y-axis direction. The diaphragm 101a is displaced so as to extend on the rear side of the connecting portion with the force receiving portion 102. The strain corresponding to the displacement can be detected by the strain sensing element provided in the strain gauge 103, and the force components in the X-axis direction and the Y-axis direction can be detected. Then, the tilt of the electronic pen and the rotation of the electronic pen can be detected from the detected force.

  By the way, in the case of having an elongated cylindrical casing such as an electronic pen and detecting a force component of an external force applied to one opening side in the axial direction of the casing, it is shown in FIG. Such a structure comprising a force receiving portion 102 having a predetermined length in the axial direction and a strain generating portion 101 provided on the side opposite to the side where the force receiving portion 102 receives external force in the axial direction is generally used. It becomes the target.

  In this case, a force in the Z-axis direction (writing pressure in the case of an electronic pen) is directly applied to the diaphragm 101a of the strain generating unit 101 via the force receiving unit 102, and the diaphragm 101a includes a material of the material. Tensile / compressive stress that causes elongation / contraction occurs. The magnitude of the tensile / compressive stress is determined only by the relationship between the cross-sectional area of the diaphragm 101a and the load.

  On the other hand, force components in the X-axis direction and the Y-axis direction orthogonal to the Z-axis direction are applied to the strain generating portion 101 as a bending moment via the force receiving portion 102, and are applied to the diaphragm 101a as bending stress and shear stress. The bending stress and the shearing stress correspond to a bending moment corresponding to the distance from the diaphragm 101a to the power point. In the electronic pen, since the power point is the tip of the core, the distance from the diaphragm 101a to the power point is equal to the length of the force receiving unit 102 or the length of the force receiving unit 102. As a result, the bending moment is increased. Therefore, the bending stress and the shear stress applied to the diaphragm 101a of the strain generating portion 101 based on the force components in the X-axis direction and the Y-axis direction are compared with the tensile / compressive stress applied to the diaphragm 101a based on the force component in the Z-axis direction. And become big.

  For this reason, the distortion generated in the diaphragm 101a due to the force component in the X-axis direction and the Y-axis direction becomes relatively large, and the force component in the X-axis direction and the Y-axis direction can be detected with relatively high sensitivity. The force component (writing pressure) in the Z-axis direction is difficult to detect with high sensitivity.

  Incidentally, there is generally a relationship as shown in FIG. 17 between the stress applied to the strain generating body and the generated strain, and the relationship of the strain ε with respect to the stress σ is a linear proportional relationship. When a stress exceeding the elastic region is applied, as shown in FIG. 17, the plastic region is reached, and the relationship between the stress and the strain is not a straight line, and in the worst case, the fracture occurs. Therefore, it is important for the strain body to make the applied stress fall within the elastic range.

  In consideration of this, in order to increase the sensitivity in the Z-axis direction in the above-described three-axis force detection sensor in the above example, the diaphragm is considered to be within the elastic range shown in FIG. It is conceivable to reduce the thickness of 101a and increase the tensile / compressive stress applied to the diaphragm 101a based on the force component in the Z-axis direction.

  However, when the thickness of the diaphragm 101a is reduced in order to increase the sensitivity in the Z-axis direction, the diaphragm 101a itself and the shear stress are caused by bending stress and shear stress based on a large bending moment due to force components in the X-axis direction and the Y-axis direction. There is a risk that the joint between the diaphragm 101a and the diaphragm holding portion 101b may break. That is, in the triaxial force detection sensor of the above example, the bending stress and the shear stress based on the bending moment due to the force component in the X-axis direction and the Y-axis direction are larger than the tensile / compressive stress due to the force component in the Z-axis direction. Therefore, even if the thickness of the diaphragm 101a is made thin so that the tensile / compressive stress based on the force component in the Z-axis direction falls within the elastic range, the X-axis direction and the Y-axis direction can be reduced. The bending stress and the shear stress due to the force component may exceed the elastic range and breakage may occur.

  In addition, when the thickness of the diaphragm 101a is reduced, the diaphragm 101a may be broken when an impact load is applied in the Z-axis direction.

  Furthermore, since the core and the force receiving portion 102 into which the core body is fitted become very thin with the recent reduction in size of the electronic pen, the force point, that is, the external force applied to the tip of the core body in the X-axis direction and There is also a possibility that the core body and the force receiving portion 102 to which the core body is fitted are damaged by a large bending moment due to the force component in the Y-axis direction.

  In view of the above points, an object of the present invention is to provide a force receiving member capable of increasing the proof strength against an applied force and a force detection sensor using the force receiving member.

To solve the above problem,
A force receiving member of a force detection sensor for detecting the received force from an electrical variable detected based on a displacement generated in response to the received force;
It has a rod-shaped part and a braking part,
The rod-shaped portion is configured to receive the force on one end side in the axial direction,
The braking portion has a cylindrical shape, and the rod-shaped portion is partially accommodated in the hollow portion of the cylindrical shape, and an inner wall surface of the cylindrical braking portion is an axis of the rod-shaped portion. It is coupled with the outer peripheral surface on the one end side in the central direction, and is spatially separated from the outer peripheral surface of the rod-shaped portion on the other end side different from the one end in the axial direction of the rod-shaped portion. Configured,
The braking portion is locked on the other end side of the rod-shaped portion, and the displacement caused by the received force is coupled to the position where the rod-shaped portion and the braking portion are coupled in the axial direction of the rod-shaped portion. The force receiving member is characterized in that it is detected by the force detection sensor disposed in the braking part on the other end side of the rod-like part.

  According to the force receiving member having the above-described configuration, the rod-shaped portion is coupled to the cylindrical braking portion that covers the periphery of the rod-shaped portion at an intermediate position in the axial direction of the rod-shaped portion. Therefore, even in the configuration in which the force detection unit provided on the other end side in the axial direction of the rod-shaped portion detects the displacement due to the force applied to the rod-shaped portion, the bending moment and the impact load due to the applied force are Therefore, it is possible to prevent breakage of the rod-shaped portion and breakage at the strain-generating portion coupled to the rod-shaped portion.

  According to the present invention, it is possible to provide a force receiving member capable of increasing the proof strength against an applied force. For this reason, while being able to provide the force detection sensor with large proof strength with respect to the applied force, an electronic pen can be provided.

It is a figure for demonstrating the example of a structure of 1st Embodiment of the force reception member by this invention. It is a figure for demonstrating the structural example of 1st Embodiment of the force detection sensor using 1st Embodiment of the force reception member by this invention. It is a figure which shows the circuit example of the distortion | strain detection circuit using 1st Embodiment of the force detection sensor by this invention. It is sectional drawing for demonstrating the structural example of the principal part of 1st Embodiment of the electronic pen using 1st Embodiment of the force detection sensor by this invention. It is a circuit diagram which shows the electronic circuit example of the electronic pen of 1st Embodiment. It is a figure for demonstrating the structural example of 2nd Embodiment of the force reception member by this invention. It is a figure for demonstrating the structural example of 2nd Embodiment of the force detection sensor using 2nd Embodiment of the force reception member by this invention. It is a figure for demonstrating the structural example of 3rd Embodiment of the force reception member and force detection sensor by this invention. It is a figure for demonstrating the example of a part of structure of 3rd Embodiment of the force detection sensor by this invention. It is sectional drawing for demonstrating the structural example of the principal part of 3rd Embodiment of the electronic pen using 3rd Embodiment of the force reception member and force detection sensor by this invention. It is sectional drawing for demonstrating the structural example of the principal part of 4th Embodiment of the electronic pen using 4th Embodiment of the force reception member and force detection sensor by this invention. It is a figure for demonstrating the example of a part of structure of 4th Embodiment of the force detection sensor by this invention. It is sectional drawing for demonstrating the structural example of the principal part of 5th Embodiment of the electronic pen using 5th Embodiment of the force reception member and force detection sensor by this invention. It is a figure which shows the electronic circuit example of the electronic pen of 5th Embodiment with the circuit example of a position detection apparatus. It is a figure for demonstrating the other example of the displacement sensitive element used by embodiment of this invention. It is a figure for demonstrating the example of the force detection sensor compared with the force detection sensor by this invention. It is a characteristic view which shows the relationship between the stress added to an elastic member, and the distortion which arises.

  Hereinafter, an embodiment of a force receiving member according to the present invention and an embodiment of a force detection sensor using the embodiment of the force receiving member will be described with reference to the drawings. Also, an embodiment of an electronic pen using the embodiment of the force detection sensor according to the present invention will be described.

[First Embodiment]
FIG. 1 is a view for explaining a structural example of a first embodiment of a force receiving member according to the present invention. The force receiving member 10 of this embodiment is configured such that a rod-shaped portion 11 and a braking portion 12 are coupled. The force receiving member 10 of this embodiment is an example of a case where the force receiving member 10 is used as a force detection sensor for detecting writing pressure, tilt angle, and rotation of an electronic pen that transmits a transmission signal to a tablet terminal by an electrostatic coupling method. The force receiving member 10 is configured to be compatible with the electrostatic coupling type electronic pen.

  FIG. 1A is a side view of an embodiment of a force receiving member 10 according to the present invention, and FIG. 1B is a longitudinal sectional view of the force receiving member 10 of this embodiment. The force receiving member 10 of this embodiment is mounted with the core 20 (see FIG. 1C) of the electronic pen of the embodiment. FIG. 1C is a cross-sectional view of an example of the core body 20. In the description of this embodiment, the axial center direction of the electronic pen core 20 is defined as the Z-axis direction, and the X-axis direction and the Y-axis direction are defined as directions orthogonal to the Z-axis direction and orthogonal to each other. To do.

  The force receiving member 10 of this embodiment includes a force component (writing pressure) in the Z-axis direction of external force applied to the core body 20 and an X-axis direction orthogonal to the Z-axis direction of external force applied to the core body 20. A strain (an example of displacement) generated in a strain generating unit, which will be described later, according to the force component and the force component in the Y-axis direction is detected by a strain detection unit as an example of a displacement detection unit.

  The rod-like portion 11 of the force receiving member 10 of this embodiment is made of a hard material having elasticity, in this example, a metal, and is a cylinder provided with a through-hole 11a for allowing the core body 20 to be fitted and penetrated. It is configured as a body. In this example, SUS is used as the metal material constituting the rod-shaped portion 11. In this example, the rod-shaped part 11 is configured to have a cylindrical shape. In the following description, the side into which the core body 20 is inserted is one end side in the axial direction of the rod-shaped portion 11 and the opposite side in the axial direction is the other end side. Therefore, in this example, force is applied to the rod-shaped portion 11 at one end side thereof.

  In this example, the braking portion 12 is a hard material having elasticity, and is made of a material different from the rod-like portion 11, for example, a resin. In this example, the braking portion 12 is shown in FIGS. Thus, it has the cylindrical shape which accommodates the rod-shaped part 11 partially in the hollow part 12a. In this example, PEEK (Polyether ether ketone) is used as the resin material constituting the braking portion 12.

  In this example, the braking portion 12 has an inner wall surface 12b on one end side in the axial direction (the same side as one end side of the rod-like portion 11) between the one end and the other end of the rod-like portion 11 in the axial direction. The cylindrical inner wall surface 12b of the brake portion 12 is separated from the outer peripheral surface 11b of the rod portion 11 at the other end side in the axial center direction. It is configured as follows. In this example, as will be described later, the braking portion 12 is as close to one end side of the rod-shaped portion 11 as possible so that the bending moment applied to the rod-shaped portion can be suppressed as much as possible by the force applied to the rod-shaped portion 11. It is combined with the rod-shaped part 11.

  That is, the inner diameter of one end side in the axial direction of the cylindrical brake portion 12 is configured to be equal to the outer diameter R <b> 2 of the rod-shaped portion 11 for coupling with the rod-shaped portion 11. The axial length of the portion 12c having an inner diameter R2 on one end side of the braking portion 12 is a predetermined length L1, and the portion 12c having the axial length L1 is a rod-shaped portion. The brake portion 12 is joined to the rod-like portion 11 by being joined to the outer peripheral surface of the rod 11. Hereinafter, the portion 12c on one end side in the axial direction of the braking portion 12 is referred to as a coupling portion 12c.

  The position of the coupling portion 12c in the axial direction is preferably as close as possible to the one end side of the rod-shaped portion 11. For example, the end surface on the one end side in the axial direction of the coupling portion 12c of the braking portion 12 and the one end side of the rod-shaped portion 11 A state where the end face is at the same position is the best. However, in this example, the force receiving member 10 has a shape in which one end side in the axial direction is the pen tip side of the housing of the electronic pen, and the pen tip side of the electronic pen is generally tapered toward the tip side. Therefore, the coupling portion 12c of the braking portion 12 is configured at the axial center position closest to the one end side of the rod-shaped portion 11 in accordance with the shape restriction.

  In this example, the cylindrical inner diameter R3 is larger than the outer diameter R2 of the rod-shaped part 11 on the other end side in the axial direction of the braking part 12 (R3> R2). A space is formed between the inner wall surface 12b on the other end side of the cylindrical brake portion 12 and the side peripheral surface 11b on the other end side of the rod-like portion 11. In this example, the portion 12d of the inner diameter R3 on the other end side in the axial direction of the braking portion 12 has a predetermined length L3, and the outer diameter of the other end portion of the length L3 is R4 and is constant. Therefore, the thickness of the portion 12d is (R4-R3) and has a constant cylindrical shape. This length L3 portion 12d is applied to the force detection sensor 10 as a force detection sensor, and when used in an electronic pen, as will be described later, in the case of the electronic pen, in the Z-axis direction and the X-axis direction. And it is set as the part latched so that it cannot move in the Y-axis direction. Hereinafter, the portion 12d on the other end side in the axial direction of the braking portion 12 is referred to as a locking portion 12d.

  And the part between the coupling | bond part 12c and the latching | locking part 12d of the braking part 12 is made into the inclined side surface part 12e which becomes taper linearly gradually from the latching | locking part 12d side to the coupling | bond part 12c side. Yes. In this embodiment, the length of the inclined side surface portion 12e in the axial center direction is a predetermined length L2, which is used as a strain generating portion as will be described later. Therefore, in this example, the braking portion 12 is configured in a truncated cone shape having an outer shape that tapers from the other end side toward the coupling portion 12c with the rod-like portion 11 in the axial direction.

  The thickness of the braking portion 12 may be the same in the coupling portion 11c, the locking portion 11d, and the inclined side surface portion 11e, but in this example, as shown in FIG. The thickness is slightly thicker than the other parts. Since the inclined side surface portion 11e is also used as a strain generating portion in this example, it may be thinner than the coupling portion 12c.

  In this case, in this example, as shown in FIGS. 1A and 1B, the axial length of the braking portion 12 is selected to be longer than the axial length of the rod-like portion 11. In the axial direction, the rod-like portion 11 is in a state where one end side and the other end side thereof are not covered with the braking portion 12. As shown in FIG. 1B, a portion of the braking portion 12 having an inner diameter equal to the outer diameter R2 of the rod-shaped portion 11 extends slightly toward the inclined side surface portion 12e rather than the coupling portion 12c. The brake part 12 is joined to the part 11 in a firmly joined state.

  In this example, the core body 20 has a configuration in which one end portion 21a side of the signal transmission core 21 made of a conductive material such as a conductive metal is protected by a pen tip protection member 22 made of, for example, a hard resin. In this example, the portion of the signal transmission core 21 that is not covered with the pen tip protection member 22 is exposed to the outside, but its surface is covered with insulation. However, the end 21b opposite to the pen tip side of the signal transmission core 21 is provided with an insulating coating so as to be electrically connected to a circuit of a printed circuit board provided in the housing of the electronic pen, as will be described later. Instead, it is exposed.

  The diameter R5 of the signal transmission core 21 is, for example, about 1 mm, and is a value (R5 <R1) smaller than the diameter R1 of the through-hole 11a of the rod-like portion 11 described above. In this example, the tip portion 21a on the pen tip protection member 22 side of the signal transmission core 21 is a sphere having a diameter slightly larger than the diameter R5.

  The pen tip protection member 22 of the core body 20 includes a pen tip portion 22 a that covers the tip end portion 21 a of the signal transmission core 21, and a fitting portion 22 b that is inserted into the through hole 11 a of the rod-like portion 11. The nib portion 22a has a conical shape with a rounded top, and a step portion 22c having a slightly larger diameter than the fitting portion 22b on the bottom surface side of the conical shape.

  In this example, the fitting portion 22b of the core body 20 is integrally formed continuously with the step portion 22c of the pen tip portion 22a, and has a columnar shape corresponding to the through hole 11a of the rod-like portion 11. In this case, the outer diameter R6 of the fitting portion 22b of the core body 20 is set to a value slightly smaller than the diameter R1 of the through hole 11a of the rod-like portion 11, and the fitting portion 22b is placed in the through hole 11a. Although fitted, the core body 20 can be easily detached from the through hole 11a when the core body 20 is pulled out. The diameter of the step portion 22c of the nib portion 22a of the core body 20 is selected to be larger than the diameter R1 of the through hole 11a of the rod-shaped portion 11.

  In the force receiving member 10 having the configuration of FIG. 1, the core body 20 is inserted into the through hole 11 a from one end side of the rod-shaped portion 11 from the side opposite to the pen tip portion 22 a of the pen tip protection member 22. The fitting portion 22b of the nib protection member 22 of the core body 20 is attached in a state of being fitted to the rod-like portion 11. Then, with the locking portion 12d on the other end side of the braking portion 12 locked so as not to move in the X-axis direction, the Y-axis direction, and the Z-axis direction, a force is applied to the pen tip portion 22a of the core body 20. Is applied to the rod-shaped portion 11 of the force receiving member 10, the force applied to the core body 20 is transmitted to the rod-shaped portion 11, and the force receiving member 10 Force components in the X-axis direction, the Y-axis direction, and the Z-axis direction are added.

  As will be described later, the force detection sensor using the force receiving member 10 is locked so that the locking portion 12d of the braking portion 12 does not move in the X-axis direction, the Y-axis direction, and the Z-axis direction. Since it is used, the stress based on the force component in the Z-axis direction of the force applied to the pen tip portion 22a of the pen tip protection member 22 of the core body 20 is tensile / compressive stress (writing pressure is mainly compressive stress). The core body 20 and the force receiving member 10 are added. Further, the force components in the X-axis direction and the Y-axis direction and the Z-axis direction are applied to the core body 20 and the force receiving member 10 as bending stress based on the bending moment.

  In this case, when the brake portion 12 is not present, when the other end side is locked to the rod-like portion 11, bending stress due to a large bending moment corresponding to the entire length of the rod-like portion 11 is applied to the rod-like portion. Join 11 On the other hand, in this embodiment, since the brake portion 12 is coupled to the rod-shaped portion 11, the bending moment is equal to the length from one end side of the rod-shaped portion 11 to the coupling portion 12c of the brake portion 12. Is applied directly to the rod-shaped portion 11, but from the position of the coupling portion 12c to the other end side of the rod-shaped portion 11, it is applied to the rod-shaped portion 11 and the braking portion 12, and the bending moment Is suppressed.

  Thereby, according to the force detection sensor using the force receiving member 10 of this embodiment, the bending moment in the X-axis direction and the Y-axis direction can be suppressed, so that the rod-shaped portion 11 and the core body 20 are prevented from being broken. In addition, the stress based on the force component in the Z-axis direction and the stress based on the force component in the X-axis direction and the Y-axis direction can be detected with good balance.

  In the force detection sensor using the force receiving member 10 of this embodiment, the locking portion 12d of the braking portion 12 is locked so as not to move in the X-axis direction, the Y-axis direction, and the Z-axis direction. The inclined side surface portion 12e of the portion 12 generates strain as displacement in the X-axis direction, the Y-axis direction, and the Z-axis direction based on the stress corresponding to the applied force.

  Therefore, in the force detection sensor using the force receiving member 10 of this embodiment, strain generated in the X-axis direction, the Y-axis direction, and the Z-axis direction on the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10 is detected. Thus, the force components in the X-axis direction, the Y-axis direction, and the Z-axis direction of the force applied to the pen tip portion 22a of the pen tip protection member 22 of the core body 20 are detected.

  In this case, as described above, the stress based on the force component in the Z-axis direction of the force applied to the pen tip portion 22a of the pen tip protection member 22 of the core body 20 is tensile / compressive stress (writing pressure is mainly compression). In the inclined side surface portion 12e of the braking portion 12, a displacement (strain) in the Z-axis direction based on a compressive stress due to a force component in the Z-axis direction is generated at a position in the axial direction adjacent to the coupling portion 12c. It is easy to do.

  Therefore, in the force detection sensor 30 using the force receiving member 10 according to this embodiment, the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10 has an axial position adjacent to the coupling portion 12c in FIG. As shown in (A) and (B), as a displacement sensitive element for detecting displacement (strain) in the Z-axis direction, in this example, four strain sensitive elements Z1 to Z4 are inclined side surface portions. 12e is provided so as to be arranged in the circumferential direction. In this case, each of the strain sensitive elements Z1 to Z4 is a strain sensitive element that changes its resistance value in accordance with the expansion and contraction of the inclined side surface portion 12e in the axial direction.

  In this case, the strain sensitive element Z1 and the strain sensitive element Z2 are separated from each other by 180 degrees, and the strain sensitive element Z3 and the strain sensitive elements Z4 are separated from each other by 180 degrees. It is arranged.

  In order to detect the strain in the Z-axis direction, one strain-sensitive sensor provided in a strip shape in the circumferential direction of the inclined side surface portion 12e is used instead of using the four strain-sensitive elements Z1 to Z4. It may be configured by an element, or two strain sensitive elements may be arranged side by side in the circumferential direction.

  The force components in the X-axis direction and the Y-axis direction of the force applied to the nib portion 22a of the nib protection member 22 of the core body 20 are bent with respect to the core body 20 and the rod-shaped portion 11 as described above. Since it acts as a moment, a strain corresponding to the bending stress is generated in the inclined side surface portion 12e of the braking portion 12. In the force detection sensor 30 of this example, as shown in FIGS. 2A and 2B, the inclined side surface portion 12e at the other end side in the axial direction from the position where the strain sensitive elements Z1 to Z4 are disposed. In this example, four strain sensitive elements X1 to X4 and Y1 to Y4 are arranged in the circumferential direction as displacement sensitive elements for detecting displacements in the X axis direction and the Y axis direction. Is provided. In this case, each of the strain sensitive elements X1 to X4 and Y1 to Y4 is a strain sensitive element that changes its resistance value in accordance with the expansion and contraction in the direction orthogonal to the axial direction in the inclined side surface portion 12e. ing.

  In this case, the set of the strain sensitive elements X1 and X2 and the set of the strain sensitive elements X3 and X4 are separated from each other by 180 degrees, and the set of the strain sensitive elements Y1 and Y2 and the strain sensitive element. The set of Y3 and Y4 is disposed so as to be 180 degrees apart from each other. The positions separated by an angular interval of 180 degrees are positions where tensile strain is generated on one side and compressive strain is generated on the other side due to bending stress due to force components in the X-axis direction and Y-axis direction.

  In order to detect strain in the X-axis direction and in the Y-axis direction, the four strain-sensitive elements X1 to X4 and the four strain-sensitive elements Y1 to Y4 are not used. The strain-sensitive elements in the axial direction and the Y-axis direction may be arranged one by one or two by two in the circumferential direction of the inclined side surface portion 12e.

  FIG. 3 shows an example of the strain detection circuit 31 configured using the strain sensitive elements Z1 to Z4, the strain sensitive elements X1 to X4, and Y1 to Y4 arranged as described above. As shown in FIG. 3, the strain detection circuit 31 in this example is a bridge circuit (Wheatstone bridge circuit) 32X, 32Y, 32Z as a circuit for detecting strain in the X-axis direction, the Y-axis direction, and the Z-axis direction. Is formed.

  As shown in FIG. 3, a plurality of terminals are derived from the strain detection circuit 31, and these terminals are electronic when the force detection sensor 30 of this embodiment is used in an electronic pen. It is connected to an electronic circuit formed on a printed circuit board provided in the pen casing.

  That is, as shown in FIG. 3, from the strain detection circuit 31, the output terminals 32Xa and 32Xb of the bridge circuit 32X for detecting the strain in the X-axis direction, and the bridge circuit 32Y for detecting the strain in the Y-axis direction. The output terminals 32Ya and 32Yb and the output terminals 32Za and 32Zb of the bridge circuit 32Z for detecting strain in the Z-axis direction are provided, and a power supply voltage is commonly applied to each of the three bridge circuits 32X, 32Y and 32Z. A terminal 32V and a terminal 32G for application are provided.

  Although the illustration of the strain detection circuit 31 is omitted, for example, on the flexible substrate made of an insulating film sheet, the magnitude of the force component in the X axis direction, the Y axis direction, and the Z axis direction as shown in FIG. A plurality of strain sensing elements X1 to X4, Y1 to Y4 and Z1 to Z4 constituting the bridge circuits 32X, 32Y and 32Z for detecting the corresponding strains are disposed, and these are arranged by a conductive pattern as shown in FIG. As shown in FIG. And the arrangement | positioning position of the strain sensitive elements X1-X4, Y1-Y4, Z1-Z4 is the position as shown to FIG. 2 (A) and (B) about the flexible substrate in which the distortion | strain detection circuit 31 is formed. Thus, the force detection sensor 30 can be configured by being attached to the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10.

  Further, instead of using such a flexible substrate, the strain sensitive elements X1 to X4, Y1 to Y4, and Z1 to Z4 are arranged at positions as shown in FIGS. 2 (A) and 2 (B). Thus, it affixes on the inclination side part 12e of the braking part 12 of the force reception member 10, and between these some distortion | strain sensitive elements X1-X4, Y1-Y4, Z1-Z4, for example, MID (Molded Interconnect Device) ) Etc. may be used for connection as shown in FIG.

[Electronic Pen of First Embodiment]
FIG. 4 is a cross-sectional view for explaining a configuration example of a main part of the electronic pen 40 on which the force detection sensor 30 of this embodiment is mounted. FIG. 4 is a cross-sectional view of one opening side in the axial direction (Z-axis direction) of the cylindrical housing 401 of the electronic pen 40 of this embodiment. A force detection sensor 30 including the force receiving member 10 is housed.

  In this example, a holder portion 402 including a placement portion on which the printed circuit board 408 is placed is accommodated in a hollow portion of the housing 401 in a state in which it cannot move in the axial direction in the hollow portion. The holder portion 402 is provided with a concave hole 402a in the axial direction, and the locking portion 12d of the force receiving member 10 of the force detection sensor 30 is fitted into the concave hole 402a. Thus, the force detection sensor 1 is locked in the hollow portion of the housing 401 so as not to move in any of the X-axis direction, the Y-axis direction, and the Z-axis direction.

  In this state, although not illustrated, the output terminals 32Xa, 32Xb, 32Ya, 32Yb, 32Za, and the like of the strain detection circuit 31 that are attached to the inclined side surface portion 12e of the force receiving member 10 of the force detection sensor 30. Each of 32Zb and the writing pressure and inclination detection circuit formed on the printed circuit board 408 are electrically connected, and the terminals 32V and 32G of the strain detection circuit 31 and the power supply circuit are electrically connected. To be made.

  As shown in FIG. 4, the core body 20 has a fitting portion 22 b of the core body 20 in the through hole 11 a of the rod-shaped portion 11 of the force receiving member 10 of the force detection sensor 30 housed in the hollow portion of the housing 401. Is inserted and locked to the force receiving member 10. At this time, the signal transmission core 21 of the core body 20 is inserted through the through hole 11 a of the force receiving member 10 to the printed circuit board 408 side in the housing 401. As shown in FIG. 4, the other end 21 b of the signal transmission core 21 of the core body 20 not electrically insulated is electrically connected to the signal line 403 connected to the electronic circuit on which the printed circuit board 408 is formed. The signal transmission core 21 is electrically connected to the electronic circuit of the printed circuit board 408.

  In the electronic pen 40 of this embodiment, a cover body 404 that covers the periphery of the force detection sensor 30 is fitted into the holder portion 402 in the axial direction in the hollow portion of the housing 401. Is provided. A screw portion 401a is formed on the opening side of the core body 20 of the housing 401 on the pen tip portion 22a side, and a sleeve coupled to the opening side of the housing 401 by being screwed to the screw portion 401a. A member 405 is provided.

  The sleeve member 405 includes an opening 405a on the pen tip portion 22a side of the core body 20, and has a truncated cone shape that tapers toward the opening 405a. The opening 405 a of the sleeve member 405 has a diameter larger than the outer diameter of the step portion 22 c of the nib portion 22 a of the core body 20. The diameter of the opening 405a of the sleeve member 405 is such that when the core body 20 receives a large force in the X-axis direction and the Y-axis direction, the stepped portion 22c and the end surface of the opening 405a of the sleeve member 405 collide with each other. The core body 20 is selected so that it functions as a stopper and the core body 20 is protected even if impact loads in the X-axis direction and the Y-axis direction are applied to the core body 30.

  In other words, the diameter of the opening 405a of the sleeve member 405 is such that when the stress due to the forces in the X-axis direction and the Y-axis direction is a predetermined stress within the elastic region of the core body 20, the step portion 22c of the core body 20 and the opening 405a. The value is selected so that it meets the end face.

  In this example, as shown in FIG. 4, the pen body 20 a side of the core body 20 of the cover body 404 is tapered according to the shape of the sleeve member 405. A coil 407 used for charging a battery (not shown) built in the electronic pen 40 is wound around the cover body 404.

  In the electronic pen 40 configured as described above, when an external force is applied to the core body 20, as described above, the strain corresponding to the force components of the external force in the X-axis direction, the Y-axis direction, and the Z-axis direction. Is generated at the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10, and a detection output signal corresponding to the magnitude of the strain is obtained from the strain detection circuit 31.

  And in the electronic pen 40 of this embodiment, while detecting the writing pressure applied to the core 20 from the detection output signal from this distortion | strain detection circuit 31, the inclination of the electronic pen 40 is detected, and it detected. Information on writing pressure and inclination is transmitted to a tablet terminal including a sensor unit used together with the electronic pen 40.

  An example of an electronic circuit in the electronic pen 40 of this embodiment is shown in FIG. As shown in FIG. 5, the coil 407 of the electronic pen 40 has an induced current caused by electromagnetic waves sent from the charging device or electromagnetic waves sent from a tablet terminal provided with a sensor unit used with the electronic pen 40. The induced current flows through a rectifying diode 51 to a capacitor such as an electric double layer capacitor 52, and charges the electric double layer capacitor 52.

  The voltage conversion circuit 53 generates the power supply voltage Vcc of the electronic circuit from the charging voltage of the electric double layer capacitor 52, and the writing pressure and inclination detection circuit 54 and the signal transmission circuit 55 formed on the distortion detection circuit 31 and the printed circuit board. To supply.

  In the strain detection circuit 31, as described above, the strain corresponding to the force component in the X-axis direction, the Y-axis direction, and the Z-axis direction of the external force applied to the core 20 of the electronic pen 40 is detected, and each direction is detected. Is supplied to the writing pressure and inclination detection circuit 54.

  The writing pressure and inclination detection circuit 54 detects the writing pressure applied to the core 20 of the electronic pen 40 from the detection output of the distortion in the Z-axis direction, and generates, for example, a digital signal corresponding to the detected writing pressure. Then, the signal is supplied to the signal transmission circuit 55. Further, the writing pressure and inclination detection circuit 54 detects an inclination angle with respect to the input surface of the sensor unit of the electronic pen 40 from the detection output of the distortion in the X-axis direction and the Y-axis direction, and according to the detected inclination angle. For example, a digital signal is generated and supplied to the signal transmission circuit 55.

  The signal transmission circuit 55 supplies a position detection signal to the sensor unit of the tablet terminal through the signal transmission core 21 of the core body 20 in an electrostatic capacity manner, and writing pressure as additional information of the position detection signal. And a signal corresponding to a digital signal of writing pressure information and inclination angle information from the inclination detection circuit 54 is supplied.

  In the electronic pen 40 in the example of FIG. 5, the digital signal of writing pressure information and inclination angle information is transmitted to the tablet terminal as additional information of the position detection signal through the signal transmission core 21 of the core body 20. However, for example, a wireless communication unit of Bluetooth (registered trademark) standard may be mounted on the electronic pen so as to perform wireless communication with the tablet terminal separately from the position detection signal.

[Second Embodiment]
The braking unit 12 in the force receiving member 10 of the first embodiment described above has a truncated cone shape, and each of the strain sensing elements X1 to X4, Y1 to Y4, Z1 to Z4 of the strain detection circuit 31 is provided. The inclined side surface portion 12e to be disposed is a curved surface. For this reason, there exists a problem that it is difficult to arrange | position the sensitive elements X1-X4, Y1-Y4, Z1-Z4.

  The force receiving member 10A of the second embodiment described below is configured to solve this problem. FIG. 6A is a side view of the force receiving member 10A of the second embodiment, and FIG. 6B is a longitudinal sectional view of the force receiving member 10A of the second embodiment. FIG. 6C is a view of the force receiving member 10A of the second embodiment viewed from one end side of the rod-shaped portion 11 in the axial direction, and FIG. 6D is the second embodiment. It is the figure which looked at the force reception member 10A of the form from the other end side of the rod-shaped part 11 in the axial direction. FIGS. 7A and 7B show an embodiment of a force detection sensor 30A in which a strain detection circuit is attached to the force receiving member 10A of the second embodiment. In the force receiving member 10A and the force detection sensor 30A of the second embodiment, the same parts as those of the force receiving member 10 and the force detection sensor 30 of the first embodiment described above are denoted by the same reference numerals.

  The force receiving member 10A of the second embodiment includes a rod-like portion 11 having the same configuration as that of the force receiving member 10 of the first embodiment, and the braking portion 12 of the force receiving member 10 of the first embodiment. 12A having a different shape from the above. The braking portion 12A of the force receiving member 10A of the second embodiment has a flat surface on which the strain sensing elements X1 to X4, Y1 to Y4, and Z1 to Z4 of the strain detection circuit 31 are disposed. In addition, in this example, as shown in FIGS. 6A and 6C, a quadrangular pyramid shape is formed.

  Therefore, the inclined side surface portion 12Ae of the braking portion 12A has four inclined flat surface portions 12Aea, 12Aeb, 12Aec, and 12Aed as shown in FIGS. In this example, as shown in FIG. 6B, the wall thickness of the four inclined plane portions 12Aea, 12Aeb, 12Aec, 12Aed of the inclined side surface portion 12Ae of the braking portion 12A is constant. Yes. This is so considered that almost the same strain is generated in each of the four inclined plane portions 12Aea, 12Aeb, 12Aec, and 12Aed.

  Since it is configured in this way, as shown in FIGS. 6B and 6D, in the force receiving member 10A of the second embodiment, the four inclined flat surface portions 12Aea of the inclined side surface portion 12Ae. , 12Aeb, 12Aec, 12Aed and the hollow space 12Aa that separates the rod-shaped portion 11 is also formed in a quadrangular pyramid shape.

  And in force reception member 10A of this 2nd embodiment, as shown in Drawing 6 (A) and (B), and Drawing 7 (A) and (B), it is with rod-like part 11 of braking part 12A. The coupling portion 12Ac is configured to have a columnar shape like the coupling portion 12c of the force receiving member 10 of the first embodiment. Further, the outer shape of the locking portion 12Ad of the braking portion 12A of the force receiving member 10A of the second embodiment has a columnar shape like the coupling portion 12c of the force receiving member 10 of the first embodiment. It is configured.

  However, the shape of the inner wall surface 12Ab of the locking portion 12Ad of the braking portion 12A of the force receiving member 10A of the second embodiment is between the braking portion 12A and the rod-shaped portion 11 as shown in FIG. Since the hollow space 12Aa has a quadrangular frustum shape, the hollow space 12Aa has a quadrangular shape.

  In the force detection sensor 30A using the force receiving member 10A of this embodiment, as shown in FIG. 7A, the inclined flat surface portion 12Aea of the inclined side surface portion 12e of the braking portion 12A has a Z-axis direction. The strain sensitive element Z1 and the strain sensitive elements Y1 and Y3 in the Y-axis direction are disposed, and the inclined plane portion 12Aeb has the strain sensitive element Z3 in the Z-axis direction and the strain sensitive element in the X-axis direction. Elements X1 and X3 are arranged. Further, as shown in FIG. 7B, the inclined flat surface portion 12Aec of the inclined side surface portion 12e of the braking portion 12A has a strain sensitive element Z2 in the Z-axis direction and strain sensitive elements Y2 and Y4 in the Y-axis direction. In addition, a strain sensitive element Z4 in the Z-axis direction and strain sensitive elements X2 and X4 in the X-axis direction are disposed in the inclined plane portion 12Aed.

  The inclined flat surface portion 12Aea and the inclined flat surface portion 12Aec of the inclined side surface portion 12e of the braking portion 12A are portions that are separated from each other by an angular interval of 180 degrees, and a force in the Y-axis direction is applied to the rod-shaped portion 11. Occasionally, the bending moment causes strains in opposite directions, ie, compressive strain on one surface and elongation strain on the other surface. Similarly, the inclined flat surface portion 12Aeb and the inclined flat surface portion 12Aed of the inclined side surface portion 12e are portions separated from each other by an angular interval of 180 degrees, and when a force in the X-axis direction is applied to the rod-shaped portion 11, Due to the bending moment, strains in opposite directions, that is, compressive strain occurs on one surface and elongation strain occurs on the other surface.

  The arrangement of the strain sensing elements X1 to X4 and Y1 to Y4 shown in FIGS. 7A and 7B is a force corresponding to the strain in consideration of the strain generation direction in the inclined plane portions 12Aea to 12Aed. This is an arrangement for allowing the components to be detected efficiently.

  The strain detection circuit 31 in the force detection sensor 30A in the second embodiment is configured in the same manner as the force detection sensor 30 in the first embodiment shown in FIG. Is omitted.

  The force detection sensor 30A of the second embodiment can be attached to the electronic pen 40 of the first embodiment shown in FIG. 4 instead of the force detection sensor 30 of the first embodiment. The electronic pen 40 of the first embodiment described above can be configured.

  According to the force receiving member 10 </ b> A and the force detection sensor 30 </ b> A of the second embodiment, the surfaces on which the strain sensing elements constituting the strain detection circuit 31 are disposed are the inclined flat surface portions 12 </ b> Aea to 12 </ b> Aed of the braking portion 12 </ b> A. Therefore, the strain detection circuit 31 can be easily mounted on the force receiving member 10A.

  Note that the force receiving member 10 in the first and second embodiments applies all three force components in the X axis direction, the Y axis direction, and the Z axis direction to the inclined side surface portion 12e of the braking portion 12. Since the strain sensing element for detection is arranged and the other end side of the rod-shaped portion 11 is a free end, the other end of the rod-shaped portion 11 is more than the coupling portion with the coupling portion 12c of the braking portion 12. The side part may be omitted. However, in the above-described first and second embodiments, the signal transmission core 21 of the core body 20 is covered by the portion of the rod-like portion 11 on the other end side of the coupling portion with the coupling portion 12c of the braking portion 12. In this example, the rod-shaped portion 11 is made of metal, and can serve as a shield for the signal transmission core 21.

[Force Detection Sensor of Third Embodiment]
In the force detection sensors 30 and 30A of the first embodiment and the second embodiment described above, the braking portions 12 of the force receiving members 10 and 10A and the inclined side surface portions 12e and 12Ae of 12A are used as the strain generating portions. The strain sensing element constituting the strain detection circuit 31 is disposed in the strain portion.

  However, the force detection sensor according to the present invention is not limited to the configuration in which the component of the force receiving member is the strain generating portion, but may be a structure in which the strain generating portion is attached to the force receiving member. The force detection sensor of the third embodiment is an example of such a configuration.

  A force detection sensor 30B according to the third embodiment will be described with reference to FIG. As the force receiving member used in the force detection sensor 30B of the third embodiment, either the force receiving member 10 of the first embodiment or the force receiving member 10A of the second embodiment can be used. In the force detection sensor 30B in the example of FIG. 8, the force receiving member 10 is used. In FIG. 8, the same parts as those of the force receiving member 10 of the first embodiment described above are denoted by the same reference numerals.

  In the force detection sensor 30 </ b> B of the third embodiment, a strain generating portion 60 and a strain gauge 70 are provided on the other end side of the rod-like portion 11 of the force receiving member 10. The strain generating portion 60 has a columnar portion 61 having an outer diameter R7 that is equal to or slightly smaller than the inner diameter R1 of the rod-shaped portion 11 of the force receiving member 10, and one end side in the axial direction of the columnar portion 61. The disk-shaped diaphragm part 62 is formed integrally with the cylindrical part 61. The diameter R8 of the diaphragm 62 is set to a value that is equal to or slightly smaller than the inner diameter R3 on the other end side of the braking portion 12 of the force receiving member 10. The strain generating portion 60 is configured such that the columnar portion 61 is positioned at the center of the disc-shaped diaphragm portion 62.

  At the center position of the columnar part 61 and the diaphragm part 62 of the strain generating part 60, an axial through hole 60a having a diameter R9 slightly larger than the diameter R5 of the signal transmission core 21 of the core body 20 is provided. Yes. As shown in FIG. 8, the strain generating portion 60 is joined by joining a cylindrical portion 61 into a through hole 11 a on the other end side of the rod-like portion 11 of the force receiving member 10, and the diaphragm portion 62. The peripheral edge portion is attached to the other end side of the force receiving member 10 so as to be joined to the inner wall surface 12 b on the other end side of the braking portion 12.

  A strain gauge 70 is attached to the diaphragm 62 of the strain generating part 60 on the side opposite to the surface on which the cylindrical part 61 is formed. As shown in FIG. 9A, the strain gauge 70 is formed on a disc-shaped insulating sheet 71 having a diameter slightly smaller than that of the diaphragm portion 62, and in this example, a plurality of resistance values whose resistance values change according to the strain. The strain sensitive elements X1, X2, Y1, Y2 and Z1 to Z4 are arranged.

  That is, the strain sensitive elements X1 and X2 are disposed at positions spaced apart from each other by 180 degrees so that the resistance value changes according to the strain in the X-axis direction, and the strain sensitive elements Y1 and Y2 Are arranged at positions that are 180 degrees apart from each other so that the resistance value changes according to the strain in the Y-axis direction. Then, the strain sensitive elements Z1 and Z2 are formed in an arc shape having an angle range slightly smaller than 180 degrees in the upper half region of the insulating sheet 71 in FIG. 9A, and the strain sensitive elements Z3 and Z4. Is formed in an arc shape with an angular range slightly smaller than 180 degrees in the lower half region of the insulating sheet 71 to detect strain in the Z-axis direction.

  And although illustration is abbreviate | omitted in FIG.9 (A), on the insulating sheet 71 so that the bridge | bridging circuit for distortion detection of an X-axis direction, a Y-axis direction, and a Z-axis direction may be comprised so that it may well be known. A conductive pattern for electrically connecting the strain sensitive elements X1, X2, Y1, Y2 and Z1 to Z4 is formed, and a terminal for connection is formed.

  The insulating sheet 71 of the strain gauge 70 is formed with a through-hole 71 a that communicates with the through-hole 60 a of the strain-generating portion 60 and allows the signal transmission core 21 of the core body 20 to penetrate.

  The force detection sensor 30B of the third embodiment configured as described above can be mounted on an electrostatic coupling type electronic pen in the same manner as in the first embodiment. FIG. 10 shows an electrostatic coupling type electronic pen 40B equipped with the force detection sensor 30B of the third embodiment. The same reference numerals are used for the same parts as those of the electronic pen 40 of the first embodiment. The description is omitted.

  As shown in FIG. 10, the force detection sensor 30B is configured such that the locking portion 12d on the other end side of the braking portion 12 is fitted into the concave hole 402a of the holder portion 402 of the electronic pen 40B. In the hollow portion of the housing 401, the housing 401 is locked so as not to move in any of the X-axis direction, the Y-axis direction, and the Z-axis direction.

  In the electronic pen 40B of the third embodiment, although not shown in FIG. 10, the terminals formed on the strain gauge 70 are connected to the circuit elements provided on the printed circuit board 408. Thus, a strain detection circuit is configured.

  Then, the core body 20 is inserted from the opening 405 a of the sleeve member 405, so that the nib protection member 22 of the core body is fitted into the through hole 11 a on one end side of the rod-shaped portion 11. At this time, the signal transmission core 21 of the core body 20 passes through the through-hole 11a of the rod-shaped portion 11, and further passes through the through-hole 60a of the strain-generating portion 60 and the through-hole 71a of the insulating sheet 71 of the strain gauge 70. It protrudes toward the substrate 408 side. In the same manner as the electronic pen 40 of the first embodiment described above, the other end 21 b of the signal transmission core 21 of the core body 20 that is not insulated is connected to the electronic circuit on which the printed circuit board 408 is formed. The signal transmission core 21 is electrically connected to the electronic circuit of the printed circuit board 408 by being electrically connected to the signal line 403.

  The configuration of the electronic circuit in the electronic pen 40B of the third embodiment is the same as that shown in FIG. Other configurations of the electronic pen 40B are the same as those in the first embodiment and the second embodiment described above.

  In the electronic pen 40B of the example of FIG. 10, when a force is applied to the pen tip portion 22a of the core body 20, the rod-like portion 11 into which the fitting portion 22b of the pen tip protection member 22 of the core body 20 is fitted. The force is transmitted to the diaphragm portion 62 of the strain-generating portion 60 on the other end side of the rod-like portion 11 to cause displacement as shown in FIGS. Produce.

  That is, in the electronic pen 40B of this example, when a force (writing pressure) in the Z-axis direction is applied to the pen tip portion 22a of the pen tip protection member 22 of the core body 20, the strain generating portion of the force detection sensor 30B. Tensile / compressive stress is applied to the diaphragm portion 62 of the 60 by the rod-shaped portion 11, and the diaphragm portion 62 protrudes downward according to the displacement of the rod-shaped portion 11 in the Z-axis direction as shown in FIG. 9B. It curves to become.

  Then, the insulating sheet 71 of the strain gauge 70 attached to the diaphragm portion 62 of the strain generating portion 60 is displaced according to the curvature of the diaphragm portion 62, and extends as shown by an arrow in FIG. 9B. Displace. For this reason, the strain-sensitive element disposed on the insulating sheet 71 of the strain gauge 70 is similarly displaced, and its resistance value changes. By detecting this change, the Z-axis direction is detected. Force (writing pressure) can be detected.

  Further, when a force component in the X-axis direction or the Y-axis direction orthogonal to the Z-axis direction is applied to the pen-tip portion 22a of the nib protection member 22 of the core body 20, the X-axis direction or the Y-axis direction. The force component acts as a bending moment on the force receiving member 10, and bending stress and shear stress are applied to the diaphragm portion 62 of the strain generating portion 60. Therefore, in the diaphragm portion 62, as shown in FIG. 9C, the strain gauge 70 side of the diaphragm portion 62 is closer to the front side of the rod-like portion 11 when viewed from the direction of applying the force in the X-axis direction or the Y-axis direction. It is displaced so as to contract, and on the rear side of the rod-shaped part 11, it is displaced so that the strain gauge 70 side of the diaphragm part 62 extends.

  The strain corresponding to the displacement in the diaphragm 62 is detected by the strain sensing elements X1, X2, Y1, and Y2 provided in the strain gauge 70, and the force components in the X axis direction and the Y axis direction are detected. can do. Then, the tilt of the electronic pen and the rotation of the electronic pen can be detected from the detected force.

  As described above, in the third embodiment, the force detection sensor 30B is configured by combining the force receiving member 10 and the strain generating portion 60, and thus the first and second embodiments described above. Although different from the form, as in the first embodiment and the second embodiment, there is an effect that it is possible to realize a force receiving member and a force detection sensor having a high resistance to bending moment.

[Fourth Embodiment]
By the way, as an example of a force detection sensor that detects a force in the Z-axis direction applied to the tip of the core of the electronic pen, that is, a writing pressure detection member that detects writing pressure, for example, Japanese Unexamined Patent Application Publication No. 2013-161307 A configuration using a semiconductor element whose capacitance is variable according to the writing pressure as disclosed is known. Conventionally, this type of semiconductor element has a problem of strength against an impact load in the Z-axis direction detected as writing pressure.

  The force receiving members 10 and 10A of the above-described embodiment have a proof strength against a bending moment and also have a proof strength against an impact load in the Z-axis direction. Therefore, by using the force receiving members 10 and 10A of the above-described embodiment, it is possible to solve the problem of the strength of the writing pressure detecting means as an example of the force detecting sensor using the semiconductor element as described above.

  In the fourth embodiment described below, in consideration of the above, the force receiving member 10 or 10A of this embodiment is used, and a semiconductor element whose capacitance is variable according to writing pressure is used. The present invention provides an electronic pen equipped with a writing pressure detection means as an example of a configured force detection sensor.

  FIG. 11 is a cross-sectional view for explaining a configuration example of a main part of the electronic pen 40C according to the fourth embodiment. As in the first to third embodiments described above, a capacitive electronic pen is used. It is a case where it applies to. In the example of FIG. 11, the force receiving member 10 of the first embodiment is used. In FIG. 11, the same reference numerals are assigned to the same parts as those of the electronic pen 40 of the first embodiment.

  In the electronic pen 40C according to the fourth embodiment, as shown in FIG. 11, a printed circuit board 408C is placed on the holder portion 402C in the housing 401. In this case, the printed circuit board 408C is provided. Is at the center position in the hollow portion of the housing 401. That is, the printed circuit board 408C is disposed so that the center position of the cross section of the printed circuit board 408C coincides with a so-called axial center that is the center line position of the cylindrical hollow section of the housing 401.

  Then, on the end surface on the pen tip side in the longitudinal direction (axial direction of the housing 401) of the printed circuit board 408C, as shown in FIG. 11, a semiconductor element 90 whose capacitance is variable according to writing pressure is provided. The used writing pressure detection member 80 is attached in a state capable of detecting writing pressure (force component in the Z-axis direction) applied to the core body 20.

  And in this 4th Embodiment, the signal transmission core of the core 20 which penetrates the through-hole 11a of the rod-shaped part 11 of the force reception member 10 and protrudes from the other end side of the rod-shaped part 11 to the printed circuit board 408C side. The other end 21 </ b> Cb of 21 is fitted to the writing pressure detection member 80. In this example, the other end portion 21 </ b> Cb of the signal transmission core 21 of the core body 20 has a shape with a rounded tip for fitting with the writing pressure detection member 80.

  12A and 12B are diagrams for explaining the configuration of the writing pressure detecting member 80. FIG. 12A is a perspective view of the writing pressure detecting member 80, and FIG. 12B is a drawing of FIG. FIG. 12C, which is a longitudinal sectional view including the AA line, is a diagram showing a state when the writing pressure detecting member 80 is attached to the printed circuit board 408C.

  In this example, the writing pressure detecting member 80 includes a pressure sensing chip 90 configured as a semiconductor chip manufactured by, for example, MEMS (Micro Electro Mechanical Systems) technology, sealed in a cubic or rectangular parallelepiped box-shaped package 81, for example. (See FIGS. 12A and 12B).

The pressure sensing chip 90 detects the applied pressure as a change in capacitance. In this example, the first electrode 91, the second electrode 92, the first electrode 91, and the second electrode are detected. And an insulating layer (dielectric layer) 93 between the electrodes 92. The pressure sensing chip 90 in this example receives the pressure P from the upper surface 91 a side of the first electrode 91. In this example, the first electrode 91 and the second electrode 92 are made of a conductor made of single crystal silicon (Si). In this example, the insulating layer 93 is composed of an insulating film made of an oxide film (SiO ₂ ). The insulating layer 93 need not be composed of an oxide film, and may be composed of other insulators.

  And in this example, the circular recessed part 94 centering on the center position of the said surface is formed in the surface side which opposes the 1st electrode 91 of the insulating layer 93. As shown in FIG. Due to the recess 94, a space is formed between the insulating layer 93 and the first electrode 91. In this example, the bottom surface of the recess 94 is a flat surface, and its diameter D is, for example, D = 1 mm. In addition, the depth of the concave portion 94 is about several tens of microns to several hundreds of microns in this example.

  Due to the presence of the space formed by the recess 94, the first electrode 91 is bent in the direction of the space formed by the recess 94 when pressed from the surface 91 a side opposite to the surface facing the second electrode 92. The electrostatic capacity Cv formed between the first electrode 91 and the second electrode 92 changes in accordance with the displacement generated in the first electrode 91 based on the pressing force P. .

  In the writing pressure detection member 80 of this embodiment, the pressure sensing chip 90 having the above-described configuration has a surface 91a of the first electrode 91 that receives pressure, as shown in FIGS. 12A and 12B. 81 is housed in the package 81 so as to face the upper surface 81a of the 81.

  In this example, the package 81 includes a package member 82 made of an electrically insulating material such as a ceramic material or a resin material, and an elastic member 83 provided in the package member 82 on the surface 91a side where the pressure sensing chip 90 receives pressure. It consists of. The elastic member 83 is an example of a pressure transmission member having a predetermined elasticity.

  In this example, a recess 82 a corresponding to the area of the first electrode 91 is provided in the upper portion of the package member 82 on the surface 91 a side of the first electrode 91 where the pressure sensing chip 90 receives pressure. The recess 82a is filled with an elastic member 83. In this example, the elastic member 83 is made of a silicon resin having a predetermined elasticity, for example, silicon rubber.

  The package 81 has a communication hole 84 that communicates from the upper surface 81 a to a part of the elastic member 83. That is, the package member 82 is formed with a through hole 82 b that constitutes a part of the communication hole 84, and the elastic member 83 is provided with a concave hole 83 a that constitutes an end of the communication hole 84. Yes. Further, a tapered portion 82c is formed on the opening portion side (upper surface 81a side) of the communication hole 84 of the package member 82, and the opening portion of the communication hole 84 has a trumpet shape.

  12A and 12B, as shown by dotted lines, the other end side 21Cb of the signal transmission core 21 of the core body 20 is inserted into the communication hole 84 in this example. In this example, the inner diameter of the through hole 82b is slightly larger than the diameter of the other end side 21Cb of the signal transmission core 21, and the inner diameter of the recessed hole 83a is recessed in the other end side 21Cb of the signal transmission core 21. By making the diameter slightly smaller than the diameter of the portion in contact with the hole 83a, the taper portion 82c and the through hole 82b can easily guide the other end side 21Cb of the signal transmission core 21 into the writing pressure detecting member 80. At the same time, the other end side 21Cb of the signal transmission core 21 inserted into the writing pressure detection member 80 is configured not to easily fall off.

  Then, as shown in FIGS. 12A and 12B, a first lead terminal 85 connected to the first electrode 91 of the pressure sensing chip 90 is led out from the package member 82 of the writing pressure detecting member 80. At the same time, the second lead terminal 86 connected to the second electrode 92 of the pressure sensing chip 90 is derived. The first lead terminal 85 is electrically connected to the first electrode 91 by, for example, a gold wire 85a. The second lead terminal 86 is electrically connected to the second electrode 92 by being led out in contact with the second electrode 92. Of course, the second lead terminal 86 and the second electrode 92 may be electrically connected by a gold wire or the like.

  In this example, the package member 82 is configured to be electrically connected to the other end portion 21Cb of the signal transmission core 21 as shown in FIGS. 12 (B) and 12 (C). Lead terminal 87 is derived.

  That is, in this example, a contact 88 made of a conductor is provided on the inner wall surface of the through hole 82 b of the communication hole 84, and the other end 21 Cb of the signal transmission core 21 is inserted into the communication hole 84. The conductor portion from which the insulation coating on the other end side 21Cb is peeled off is configured to be electrically connected to the contact point 88. The contact 88 is electrically connected to the third lead terminal 87 by a gold wire 87a.

  In this example, the first, second, and third lead terminals 85, 86, and 87 are made of a conductor and are wide as shown. In this example, the first, second, and third lead terminals 85, 86, and 87 are led out from the bottom surface 81b facing the top surface 81a of the package 81 in a direction perpendicular to the bottom surface 81b. At the same time, the first and third lead terminals 85 and 87 and the second lead terminal 86 are spaced from each other at an interval corresponding to the thickness d of the printed circuit board 408C on which the writing pressure detection member 80 is disposed. It is derived | led-out so that it may oppose in parallel.

  Then, as shown in FIG. 12C, the first and third lead terminals 85 of the writing pressure detecting member 80 are in a state where the bottom surface 81b of the package 81 is in contact with the end surface 408Ca of the printed circuit board 408C. And 87 and the second lead terminal 86 (the second lead terminal 86 is not shown in FIG. 12C) so as to sandwich the thickness direction of the printed circuit board 408C. Note that a positioning projection 81c is provided on the bottom surface 81b of the package 81, and this projection 81c is fitted into a concave hole (not shown) provided in the end surface 408Ca of the printed circuit board 408C. The writing pressure detection member 80 is positioned with respect to the printed circuit board 408C.

  Then, the printed wiring patterns 409 and 410 provided on the one surface 408Cb of the printed board 408C, the first lead terminal 85 and the third lead terminal 87 are electrically connected and fixed by the solder 411 and 412. Although not shown, similarly, the printed wiring pattern provided on the surface opposite to the one surface 408Cb of the printed board 408C and the second lead terminal 86 are soldered and fixed.

  In this example, although not shown, the printed circuit board 408C includes a printed wiring pattern 409 to which the first lead terminal 85 is connected and a printed wiring pattern to which the second lead terminal 86 is connected. A signal processing circuit to which the printed wiring pattern 410 to which the third lead terminal 87 is connected is connected and a signal processing circuit to be connected are provided. The signal processing circuit detects the writing pressure from the electrostatic capacitance Cv of the pressure sensing chip 90 of the writing pressure detection member 80, supplies the detected writing pressure to the signal transmission circuit, and controls the signal transmission circuit. To do. The signal transmission circuit sends a position detection signal to a position detection sensor used together with the electronic pen 40C, and receives control of the signal processing circuit to obtain information on writing pressure from the signal processing circuit, for example, a core. A process of sending out through the body 20 is performed.

  In this state, when a pressing force P is applied to the writing pressure detection member 80 in the axial direction via the other end portion 21Cb of the signal transmission core 21 of the core body 20, as shown in FIG. A pressure corresponding to the pressure P is applied to the pressure sensing chip 90 via the elastic member 83. Then, the first electrode 91 of the pressure sensing chip 90 is deflected according to the applied pressure, and the capacitance Cv of the pressure sensing chip 90 changes according to the applied pressure. The signal processing circuit provided on the printed circuit board 408C performs signal processing according to the capacitance value of the electrostatic capacitance Cv.

  And in the electronic pen 40C of the fourth embodiment. The force applied to the core body 20 is not applied directly to the first electrode of the pressure sensing chip 90 but is applied via the force receiving member 10. Furthermore, in this example, the elastic member 83 is interposed between the other end portion 21 </ b> Cb of the signal transmission core 21 of the core body 20 and the first electrode 91 of the pressure sensing chip 90. This improves the pressure resistance and shock resistance of the first electrode 91 to which the pressure sensing chip 90 receives pressure, and the first electrode 91 is damaged by excessive pressure, unexpected momentary pressure, and the like. Can be prevented.

  Although not shown in FIG. 11, in the electronic pen 40C of the fourth embodiment, the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10 is shown in FIGS. As shown in FIG. 4, strain sensitive elements X1 to X4 for detecting strain in the X-axis direction and strain sensitive elements Y1 to Y4 for detecting strain in the Y-axis direction are arranged. However, in the electronic pen 40C of the fourth embodiment, since the displacement in the Z-axis direction is detected by the writing pressure detecting member 80 as described above, the inclined side surface portion 12e has the structure shown in FIG. ) And strain sensing elements Z1 to Z4 in the Z-axis direction shown in (B) are not provided. That is, in the force detection sensor 30C used in the electronic pen 40C of the fourth embodiment, the force component in the X-axis direction and the Y-axis direction is the displacement (strain) in the inclined side surface portion 12e of the force receiving member 10. The force component in the Z-axis direction is constituted by the writing pressure detection member 80.

  And in this 4th Embodiment, the bridge | bridging circuit about the strain sensitive elements X1-X4 for detecting the distortion | strain in X-axis direction, and the strain sensitive elements Y1-Y4 for detecting the distortion | strain in a Y-axis direction. However, the strain detection circuit is provided on the printed circuit board 408C, and the tilt angle and rotation of the electronic pen 40C are detected by the force components in the X-axis direction and the Y-axis direction detected by the strain detection circuit. Then, the detected inclination angle information and rotation information are transmitted through the core body 20 as a signal from the signal transmission circuit in the same manner as the writing pressure.

  Similarly to the electronic pen of the first embodiment, in the electronic pen of the fourth embodiment, the writing pressure information, the inclination angle information, and the rotation information are not sent from the core body 20 but separately. You may make it transmit using a wireless transmission means.

  In the electronic pen according to the fourth embodiment, the inclined side surface portion 12e of the force receiving member 10 has strain-sensitive elements X1 to X4 for detecting strain in the X-axis direction and strain in the Y-axis direction. It is good also as a structure which detects only the pen pressure, without providing the strain sensitive elements Y1-Y4 for detecting.

[Fifth Embodiment]
In the above first to fourth embodiments, the electronic pen is of the electrostatic coupling type, but the present invention can also be applied to an electromagnetic induction type electronic pen.

  FIG. 13 is a cross-sectional view for explaining a configuration example of a main part of the electronic pen 40D of the fifth embodiment of the electromagnetic induction method. This example is a modification of the above-described fourth embodiment of the electromagnetic induction method. This is the case when applied to an electronic pen. In FIG. 13, the same reference numerals are given to the same parts as those of the electronic pen 40 </ b> C of the fourth embodiment in FIG. 11, and detailed description thereof is omitted.

  As shown in FIG. 13, in the electronic pen 40D of the fifth embodiment, the writing pressure detection member 80D is attached to the end of the printed circuit board 408D, and the writing pressure detection member 80D is used to attach the core 20D. It is comprised so that the applied pen pressure can be detected. The writing pressure detection member 80D of this example has a configuration in which the third lead terminal 87, the contact 88, and the gold wire 87a connecting them are removed from the writing pressure detection member 80 shown in FIG.

  The force receiving member 10D in the fifth embodiment is also configured in the same manner as the force receiving member in the above-described embodiment in the configuration including the rod-shaped portion 11D and the braking portion 12 coupled to the rod-shaped portion 11D. 12, the inner wall surface 12b on one end side in the axial direction is coupled to the outer peripheral side surface 11Db of the rod-shaped portion 11D at an intermediate position between one end and the other end in the axial direction of the rod-shaped portion 11D. On the other end side in the central direction, the cylindrical inner wall surface 12b of the braking portion 12 is configured to be separated from the outer peripheral surface 11Db of the rod-shaped portion 11D. However, the force receiving member 10D in the fifth embodiment is different in the configuration of the rod-shaped portion 11D from the rod-shaped portion 11 of the force receiving member 10 in the above-described embodiment.

  That is, as shown in FIG. 13, the rod-like portion 11D of the force receiving member 10D according to the fifth embodiment does not include a through hole in the axial direction, and the solid cylindrical member is provided with this electromagnetic induction type electron. It is set as the structure which provided the concave hole 11Da which fits core 20D for pen 40D. In this example, a pressing protrusion 11Dc that fits to press the pressure sensing chip 90 of the writing pressure detection member 80D is formed on the other end side of the rod-shaped portion 11D. The pressing protrusion 11Dc plays the same role as the other end 21Cb of the signal transmission core 21 of the core body 20 in the case of the electronic pen 40C of the fourth embodiment.

  The core body 20D in the electronic pen 40D of the fifth embodiment is configured by removing the signal transmission core 21 of the core body 20 for the electrostatic coupling type electronic pen and only the pen tip protection member 22 portion. It has the same configuration as that. That is, the core body 20 </ b> D is made of, for example, a hard resin material, and includes a pen tip portion 20 </ b> Da and a fitting portion 20 </ b> Db inserted into the recessed hole 11 </ b> Da of the rod-like portion 11. The nib portion 20Da has a conical shape with a rounded top, and a step portion 20Dc having a slightly larger diameter than the fitting portion 20Db on the bottom surface side of the conical shape.

  As shown in FIG. 13, the core body 20D is attached to the force receiving member 10D by press-fitting the fitting portion 20Db into the recessed hole 11Da of the rod-like portion 11D of the force receiving member 10D. Is done. However, the core body 20D can be easily detached from the rod-shaped portion 11D of the force receiving member 10D by strongly pulling the core body 20D.

  In this state, when a pressure is applied to the pen tip portion 20Da of the core body 20D, the core body 20D and the rod-shaped portion 11D are integrally displaced with respect to the applied pressure. Pressure is transmitted to the pressure sensing chip 90 of the writing pressure detecting member 80D by the pressing protrusion 11Dc on the other end side, and the writing pressure is detected as a change in capacitance. The detected writing pressure information is transmitted from the electronic pen 40D of this embodiment to an electromagnetic induction type position detecting device by electromagnetic coupling in this example.

  Also in the electronic pen 40D of the fifth embodiment, the inclined side surface portion 12e of the braking portion 12 of the force receiving member 10D is for detecting strain in the X-axis direction as in the case of the fourth embodiment. Strain sensitive elements X1 to X4 and strain sensitive elements Y1 to Y4 for detecting strain in the Y-axis direction are provided. In the electronic pen 40D of the fifth embodiment, strain sensitive elements X1 to X4 for detecting strain in the X-axis direction and strain sensitive elements Y1 to Y4 for detecting strain in the Y-axis direction. A strain detection circuit 31D (see FIG. 14 described later) including a bridge circuit is provided, and the tilt angle of the electronic pen 40D is determined from the force components in the X-axis direction and the Y-axis direction detected by the strain detection circuit 31D. In this example, the information on the tilt angle and rotation is transmitted to the electromagnetic induction type position detection device by electromagnetic coupling.

  FIG. 14 shows an example of a circuit configuration of a position detection device 200 that exchanges signals with the electronic pen 40D by electromagnetic inductive coupling as an example of the electronic circuit formed on the printed circuit board 408D of the electronic pen 40D of the fifth embodiment. It is a figure shown with.

  In this embodiment, the electronic pen 40D transmits and receives a position detection signal by electromagnetic induction coupling with a conductor of the sensor of the position detection device 200, and writing pressure information detected through the writing pressure detection member 80D and distortion. Information on the tilt angle and rotation of the electronic pen 40 </ b> D detected from the output of the detection circuit 31 </ b> D is transmitted to the position detection device 200.

  In the electronic pen 40 </ b> D, a capacitor 501 is connected in parallel to the coil 407 to form a parallel resonance circuit 502. As shown in FIG. 14, the electronic pen 40D includes a pen control circuit 510 that controls the entire electronic circuit of the electronic pen 40D, which is an IC in this example.

  Then, the AC signal received by electromagnetic coupling from the position detection device 200 by the parallel resonance circuit 502 is supplied to the rectification circuit 504 including the diodes 505 and 506 and the capacitor 507 for storing the rectified voltage through the capacitor 503 and rectified. And stored in the capacitor 507. The rectified output voltage obtained across the capacitor 507 is stabilized by the voltage stabilizing circuit 508 and supplied as the power supply voltage for the pen control circuit 510.

  In the electronic pen 40D of this embodiment, a switch circuit 509 is connected in parallel with the parallel resonance circuit 502. The switch circuit 509 is configured to be on / off controlled by the pen control circuit 510.

  In the electronic pen 40D of this embodiment, as shown in FIG. 14, the pen control circuit 510 is connected to a variable capacitor 90C constituted by the pressure sensing chip 90 of the writing pressure detection member 80D. A resistor 511 is connected in parallel to the variable capacitor 90C. In this example, the pen control circuit 510 charges the variable capacitor 90C and then discharges it through the resistor 511. The voltage at the terminal to which the variable capacitor 90C is connected (corresponding to the voltage across the variable capacitor 90C) is a predetermined threshold value. The electrostatic capacity of the variable capacitor 90C is measured by measuring the time until it becomes.

  The pen control circuit 510 detects a change in the writing pressure from the measured change in the capacitance of the variable capacitor 90C, detects whether or not the writing pressure is applied to the core 20D, and the writing pressure is applied. When this is detected, the writing pressure value is calculated from the capacitance value of the variable capacitor 90C.

  In this embodiment, the pen control circuit 510 performs on / off control of the switch circuit 509 on the calculated writing pressure value information (writing pressure data) based on the writing pressure data, thereby generating a multi-bit digital signal. The ASK signal or the OOK signal is transmitted to the position detection device 200.

  The pen control circuit 510 also calculates the tilt angle and rotation of the electronic pen 40D from the output of the force component in the X-axis direction and the Y-axis direction detected by the strain detection circuit 31D, and information on the calculated tilt angle and rotation. Is transmitted to the position detection device 200 as an ASK signal or an OOK signal by controlling the switching circuit 509 on / off by each bit of the digital signal.

  On the other hand, in the position detection device 200, as shown in FIG. 14, an X-axis direction loop coil group 211X and a Y-axis direction loop coil group 212Y are stacked to form a position detection coil. Each of the loop coil groups 211X and 212Y is composed of, for example, n and m rectangular loop coils, respectively. The loop coils constituting the loop coil groups 211X and 212Y are arranged so as to be sequentially overlapped at equal intervals.

  The position detection apparatus 200 is provided with a selection circuit 213 to which the X-axis direction loop coil group 211X and the Y-axis direction loop coil group 212Y are connected. The selection circuit 213 sequentially selects one loop coil of the two loop coil groups 211X and 212Y.

  Further, the position detection device 200 includes an oscillator 221, a current driver 222, a switching connection circuit 223, a reception amplifier 224, a detector 225, a low-pass filter 226, a sample hold circuit 227, and an A / D conversion circuit. 228 and a processing control unit 229 are provided. The processing control unit 229 is configured by a microcomputer, for example.

  The oscillator 221 generates an AC signal having a frequency f0. The resonance frequency of the resonance circuit 111 of the electronic pen 40D is selected so that the frequency f0 is the center frequency. Then, the AC signal generated by the oscillator 221 is supplied to the current driver 222. The current driver 222 converts the AC signal supplied from the oscillator 221 into a current and sends it to the switching connection circuit 223. The switching connection circuit 223 switches the connection destination (transmission side terminal T, reception side terminal R) to which the loop coil selected by the selection circuit 213 is connected under the control of the processing control unit 229. Among the connection destinations, a current driver 222 is connected to the transmission side terminal T, and a reception amplifier 224 is connected to the reception side terminal R.

  The induced voltage generated in the loop coil selected by the selection circuit 213 is sent to the reception amplifier 224 via the selection circuit 213 and the switching connection circuit 223. The reception amplifier 224 amplifies the induced voltage supplied from the loop coil and sends it to the detector 225.

  The detector 225 detects the induced voltage generated in the loop coil, that is, the received signal, and sends it to the low-pass filter 226. The low-pass filter 226 has a cutoff frequency sufficiently lower than the above-described frequency f0, converts the output signal of the detector 225 into a DC signal, and sends it to the sample hold circuit 227. The sample hold circuit 227 holds a voltage value at a predetermined timing of the output signal of the low-pass filter 226, specifically at a predetermined timing during the reception period, and sends it to an A / D (Analog to Digital) conversion circuit 228. The A / D conversion circuit 228 converts the analog output of the sample hold circuit 227 into a digital signal and outputs the digital signal to the processing control unit 229.

  The processing control unit 229 controls the selection of the loop coil in the selection circuit 213, switching of the switching connection circuit 223, and timing of the sample hold circuit 227. Based on the input signal from the A / D conversion circuit 228, the processing control unit 229 causes the X-axis direction loop coil group 211X and the Y-axis direction loop coil group 212Y to transmit electromagnetic induction signals with a constant transmission duration.

  An induced voltage is generated in each loop coil of the X-axis direction loop coil group 211X and the Y-axis direction loop coil group 212Y by an electromagnetic induction signal transmitted from the electronic pen 40D. The processing control unit 229 calculates the coordinate value of the indicated position in the X axis direction and the Y axis direction of the electronic pen 40D based on the level of the voltage value of the induced voltage generated in each loop coil.

  In addition, the processing control unit 229 supplies the current driver 222 with an inspiration signal and a signal for transmission signal level control for intermittently controlling the transmission signal, as well as writing pressure data and identification information from the electronic pen 40D. The reception process of the additional information is performed. The processing control unit 229 detects an intermittent signal including, for example, an ASK signal from the electronic pen 40D as a multi-bit digital signal, and detects additional information such as writing pressure data and identification information.

[Operation of Electronic Pen 40D and Operation of Position Detection Device 200]
The position detection device 200 transmits a transmission signal based on the process control of the process control unit 229. Note that the electronic pen 40D can receive an AC signal transmitted from the dedicated charging device by electromagnetically coupling with the dedicated charging device instead of the position detection device 200.

  In the electronic pen 40D, when the AC signal from the position detection device 200 or the charging device is not received by the parallel resonance circuit 502, the capacitor 507 of the rectifier circuit 504 is not charged.

  When the electronic pen 40D enters a state where the parallel resonance circuit 502 receives an AC signal from the position detection device 200 or the charging device, the AC signal received by the parallel resonance circuit 502 is rectified by the rectification circuit 504, and the capacitor 507 is received. Is stored. The pen control circuit 510 can operate stably by the power supply voltage from the voltage stabilization circuit 508 if the rectified output voltage obtained in the capacitor 507 of the rectifier circuit 504 is equal to or higher than a predetermined voltage.

  In this case, when the switch circuit 509 of the electronic pen 40D is OFF, the parallel resonance circuit 502 performs a resonance operation on the AC signal transmitted from the position detection device 200, and sends an electromagnetic induction signal to the position detection device 200. Return (return) to. The loop coils 211X and 212Y of the position detection device 200 receive the electromagnetic induction signal from the resonance circuit 502 of the electronic pen 40D. On the other hand, when the switch circuit 509 of the electronic pen 40D is on, the parallel resonance circuit 502 is in a state in which the resonance operation for the AC signal from the position detection device 200 is prohibited. The electromagnetic induction signal is not returned (returned) from 502 to the position detection device 200, and the loop coils 211X and 212Y of the position detection device 200 do not receive the signal from the electronic pen 40D.

  In this example, the processing control unit 229 of the position detection device 200 performs an AC signal from the oscillator 221 while sequentially switching the loop coil 211X and the loop coil 212Y during the position detection operation for detecting the position designated by the electronic pen 40D. Is transmitted to the electronic pen 40D and switched to reception after transmission, and the level of the feedback signal is detected. At the time of position detection, the pen control circuit 510 of the electronic pen 40D always turns off the switch circuit 509 and always returns the AC signal received by the parallel resonance circuit 502 to the position detection device 200.

  The processing control unit 229 of the position detection device 200 monitors the level of the level of the feedback signal received by each of the loop coil 211X and the loop coil 212Y, and based on the level, determines the coordinate position indicated by the electronic pen 40D. To detect.

  In this example, the processing control unit 229 of the position detection device 200 detects the presence / absence of a reception signal from the electronic pen 40D by performing the number of times corresponding to the number of bits of information transmitted from the electronic pen 40D. Receives information of a multi-bit digital signal.

  On the other hand, as described above, the pen control circuit 510 of the electronic pen 40D generates a multi-bit digital signal corresponding to information such as writing pressure data transmitted to the position detection device 200, and the multi-bit digital signal The switch circuit 509 is turned on / off in synchronization with transmission / reception of an electromagnetic induction signal to / from the position detection device 200.

  The processing control unit 229 of the position detection device 200 detects the presence / absence of a reception signal from the electronic pen 40D by the number of times corresponding to the number of bits of information transmitted from the electronic pen 40D, so that the electronic pen that is a digital signal is used. Information from 40D can be received.

  The force receiving member 10D constituting the electronic pen 40D of the fifth embodiment has the same effects as the force receiving member of the above-described embodiment. Therefore, even in the electronic pen 40D of the fifth embodiment, even if the writing pressure detection member 80D using the pressure sensing chip 90 as a semiconductor element is used, the proof strength is increased with respect to the force applied from the outside.

  The electromagnetic induction type electronic pen 40D described above has been described as applied to the fourth embodiment of the electrostatic coupling type electronic pen, but the first to third of the electrostatic coupling type electronic pens are described. The present invention can also be applied to the embodiment. In that case, when applied to the first embodiment and the second embodiment, the force receiving members 10 and 10A are provided with three side axes of the X axis direction, the Y axis direction, and the Z axis direction on the inclined side surface portion 12e. A strain sensing element for detecting all force components is provided, and the other end side of the rod-shaped portion 11D does not need to press the writing pressure detection member 80D. You may abbreviate | omit the solid part of rod-shaped part 11D of the other end side rather than a coupling | bond part.

[Other Embodiments or Modifications]
Regarding the force component in the X-axis direction and the Y-axis direction in the force detection sensor in the above-described embodiment, the strain, which is a displacement generated in the strain generating portion based on the force component, is detected. As described above, the present invention is not limited to one that detects a resistance change according to strain as in the above example.

  FIG. 15 shows an example of a strain sensing element that detects a change in capacitance according to a strain that is a displacement generated in the strain generating portion. That is, in the strain sensitive element 300 of this example, a plurality of first electrodes 301 and a plurality of second electrodes 302 connected to each other on a flexible substrate 303 made of an insulating sheet are shown in FIG. As shown to (A), it arrange | positions at the comb-tooth shape. The plurality of first electrodes 301 are commonly connected to the first terminal TX, and the plurality of second electrodes 302 are commonly connected to the second terminal RX.

  In the strain sensitive element 300 having the configuration of FIG. 15A, a capacitor 300C is connected between the first terminal TX and the second terminal RX as shown in the equivalent circuit of FIG. It will be what. If a transmission signal of an AC signal is supplied to the first terminal TX, a reception signal having a signal level corresponding to the capacitance of the capacitor 300C can be obtained from the second terminal RX.

  For example, as shown in FIG. 15D, when the strain sensitive element 300 is attached to the upper surface of the plate-like strain generating portion 310, the strain generating portion 310 receives a force in the Z-axis direction. In this case, since the strain generating portion 310 is bent as shown in FIG. 15E and the upper surface of the strain generating portion 310 is distorted so as to be contracted, the strain sensing element 300 on the upper surface of the strain generating portion 310 is flexible. The substrate 303 is also displaced to contract as shown in FIGS. 15 (C) and 15 (E). For this reason, in the strain sensitive element 300, the space | interval of the 1st electrode 301 and the 2nd electrode 302 becomes narrow, and the electrostatic capacitance of the capacitor 300C changes so that it may become large.

  On the other hand, as shown in FIG. 15G, for example, when the strain sensitive element 300 is attached to the lower surface of the plate-like strain generating portion 310, the strain generating portion 310 receives a force in the Z-axis direction. In this case, since the strain generating portion 310 is bent as shown in FIG. 15H and the lower surface of the strain generating portion 310 is distorted so as to contract, the flexible portion of the strain sensing element 300 on the lower surface of the strain generating portion 310 is flexible. The substrate 303 also extends as shown in FIGS. 15 (F) and 15 (H). For this reason, in the strain sensitive element 300, the space | interval of the 1st electrode 301 and the 2nd electrode 302 becomes wide, and the electrostatic capacitance of the capacitor 300C changes so that it may become small.

  Since the level of the reception signal obtained at the second terminal RX of the strain sensing element 300 depends on the capacitance of the capacitor 300C, the level of the reception signal obtained at the second terminal RX. By detecting this, it is possible to detect the strain generated in the strain generating section 310, and it is possible to detect the applied force from the detected strain.

  In the third embodiment, in the force detection sensor 30B, the strain gauge 70 using the strain sensing element whose resistance value changes according to the strain is attached to the strain generating portion 60. In the portion of the strain gauge 70, a strain sensitive element whose capacitance changes in accordance with the strain shown in FIG. 15 may be used.

  In the force receiving members 10, 10 </ b> A, 10 </ b> D of the above-described embodiment, the rod-like parts 11, 11 </ b> D and the braking parts 12, 12 </ b> A, 12 </ b> D are made of different materials and coupled. However, the rod-like parts 11 and 11D and the braking parts 12, 12A and 12D may be made of the same material and coupled. For example, the rod-shaped portions 11 and 11D and the braking portions 12, 12A, and 12D may be made of the same material such as metal or hard resin. In that case, in the first embodiment and the second embodiment, the braking portions 12 and 12A are also used as strain generating portions, so the braking portions 12 and 12A are applied to the rod-shaped portion 11. You may make it comprise with thin metal and resin so that it may be easy to produce distortion according to external force.

  When the rod-like portions 11 and 11D and the braking portions 12, 12A and 12D are both made of the same material such as metal or hard resin, the rod-like portions 11 and 11D and the braking portions 12, 12A and 12D are separated. It is also possible to configure integrally instead of the members.

10, 10 </ b> A, 10 </ b> D ... force receiving member, 11, 11 </ b> D ... rod-like portion, 11 b ... outer peripheral side surface of rod-like portion 11, 12, 12 </ b> A, 12 </ b> D ... braking portion, 12 a. 12b ... Inner wall surface of braking part, 12c ... Coupling part, 12d ... Locking part, 12e ... Inclined side face part, 20, 20D ... Core, 30, 30A, 30C, 30D ... Force detection sensor, 31 ... Strain detection circuit, 40, 40B, 40C, 40D ... electronic pen,

Claims (14)

A force receiving member of a force detection sensor for detecting the received force from an electrical variable detected based on a displacement generated in response to the received force;
It has a rod-shaped part and a braking part,
The rod-shaped portion is configured to receive the force on one end side in the axial direction,
The braking portion has a cylindrical shape, and the rod-shaped portion is partially accommodated in the hollow portion of the cylindrical shape, and an inner wall surface of the cylindrical braking portion is an axis of the rod-shaped portion. It is coupled with the outer peripheral surface on the one end side in the central direction, and is spatially separated from the outer peripheral surface of the rod-shaped portion on the other end side different from the one end in the axial direction of the rod-shaped portion. Configured,
The braking portion is locked on the other end side of the rod-shaped portion, and the displacement caused by the received force is coupled to the position where the rod-shaped portion and the braking portion are coupled in the axial direction of the rod-shaped portion. Further, the force receiving member is configured to be detected by the force detection sensor disposed in the braking portion on the other end side of the rod-shaped portion. The force receiving member according to claim 1, wherein the rod-shaped portion is made of metal, and the braking portion is made of resin. The said braking part has the external shape which tapers toward the coupling | bond part with the said rod-shaped part in the axial direction from the said other end side of the said rod-shaped part. Force receiving member. The force receiving member according to claim 1, wherein the rod-shaped portion is provided with a recess or a through hole in an axial direction. A force detection sensor comprising a force detector for detecting the received force from an electrical variable detected based on a displacement generated in response to a force received by a force receiving member,
The force receiving member is
It has a rod-shaped part and a braking part,
The rod-shaped portion is configured to receive the force on one end side in the axial direction,
The braking portion has a cylindrical shape, and the rod-shaped portion is partially accommodated in the hollow portion of the cylindrical shape, and an inner wall surface of the cylindrical braking portion is an axis of the rod-shaped portion. It is combined with the outer peripheral surface on the one end side in the central direction, and is spatially separated from the outer peripheral surface of the rod-shaped portion on the other end side different from the one end side in the axial direction of the rod-shaped portion. Is configured as
The braking portion is locked on the other end side of the rod-shaped portion, and the displacement caused by the force received by the force receiving member is applied to the rod-shaped portion and the braking portion in the axial direction of the rod-shaped portion. A force detection sensor configured to be detected by the force detection unit disposed in the braking unit on the side of the other end of the rod-shaped part with respect to the coupling position. The force detection unit is provided with a plurality of displacement sensing elements that sense the axial force received by the force receiving member and the force orthogonal to the axial direction. The force detection sensor according to claim 5. The force detector includes a diaphragm on the other end side in the axial direction of the rod-shaped portion, and the diaphragm receives the force in the axial direction received by the force receiving member and the axial direction in the diaphragm. The force detection sensor according to claim 5, wherein a plurality of displacement sensing elements that sense forces in directions orthogonal to each other are provided. A force detection sensor for detecting a force applied to a core provided so that a tip portion projects outward from one opening in the axial direction of the cylindrical casing is provided on the cylindrical casing. An electronic pen provided inside,
The force detection sensor is configured to detect the received force from an electrical variable detected based on a displacement generated in response to the force received by the force receiving member,
The force receiving member is
It has a rod-shaped part and a braking part,
The rod-shaped portion is configured to receive the force on one end side in the axial direction,
The braking portion has a cylindrical shape, and the rod-shaped portion is partially accommodated in the hollow portion of the cylindrical shape, and an inner wall surface of the cylindrical braking portion is an axis of the rod-shaped portion. It is combined with the outer peripheral surface on the one end side in the central direction, and is spatially separated from the outer peripheral surface of the rod-shaped portion on the other end side different from the one end side in the axial direction of the rod-shaped portion. Is configured as
The braking portion is locked on the other end side of the rod-shaped portion, and the displacement caused by the force received by the force receiving member is applied to the rod-shaped portion and the braking portion in the axial direction of the rod-shaped portion. An electronic pen configured to be detected by the force detection sensor disposed in the braking portion on the side of the other end of the rod-shaped portion with respect to the coupling position. The force detection sensor is provided with a plurality of displacement sensing elements that sense the axial force received by the force receiving member and the force orthogonal to the axial direction. The electronic pen according to claim 8. The force detection sensor includes a diaphragm on the other end side in the axial direction of the rod-shaped portion, and the diaphragm receives the force in the axial direction received by the force receiving member and the axial direction in the diaphragm. The electronic pen according to claim 8, further comprising a plurality of displacement sensing elements that sense forces in directions orthogonal to each other. The side of the opening of the housing from which the tip of the core body protrudes has an outer shape that tapers toward the opening,
The braking portion of the force receiving member has an outer shape that tapers from the other end side of the rod-shaped portion toward the coupling portion with the rod-shaped portion in the axial direction. The electronic pen according to claim 8. The rod-shaped portion of the force receiving member includes a through hole that penetrates the core body in the axial direction,
The force detector is fitted to the core on the side opposite to the tip side of the core passing through the rod-shaped portion of the force receiving member.
The electronic pen according to claim 8. With a signal transmission circuit,
The core body includes a conductor portion for sending a signal from the signal transmission circuit from the tip portion of the core body,
13. The electronic pen according to claim 12, wherein the conductor portion of the core body is electrically connected to the signal transmission circuit through the through hole of the rod-shaped portion. On the opening side of the housing, a coil that constitutes a part of a resonance circuit is provided.
The electronic pen according to claim 8.

Images