Pressure sensing pointer

A pressure sensing pointer includes a housing, an electromagnetic unit, a cartridge, a pressing member, a first elastic member, a second elastic member, and a pressure sensing element. The housing has an accommodating space and a port in communication with the accommodating space. The electromagnetic unit is located inside the accommodating space. The cartridge is movably disposed at the port along an axial direction. The pressing member is movably disposed in the accommodating space, and is in linkage connection to the cartridge. One end of the first elastic member is fixed on the pressing member. One end of the second elastic member abuts against the pressing member An amount of compression deformation of the second elastic member in the axial direction is greater than an amount of compression deformation of the first elastic member in the axial direction. The pressure sensing element faces toward the first elastic member.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. § 119(a) to Patent Application No. 201810890625.8 filed in China, P.R.C. on Aug. 7, 2018, the entire contents of which are hereby incorporated by reference.

BACKGROUND

Technical Field

Embodiments of the present invention relate to an indicator, and in particular, to a pressure sensing pointer.

Related Art

With the development of science and technology, more electronic devices use touch panels as control interfaces, for example, smartphones, tablet computers, or personal digital assistants (PDA). This enables users to perform operations in a touch manner, thereby improving convenience. In addition, to achieve a faster and more accurate operation process of a touch panel, a pen-type pointer is recommended for input (for example, writing or tapping).

A type of a pointer is determined based on a touch manner of a touch panel. At present, relatively widely applied touch manners of touch panels are resistive touch manner, capacitive touch manner, electromagnetic touch manner, and the like. An electromagnetic touch technology is mainly that handwriting is formed by electromagnetic signals that are detected by using a digitizer tablet and that are from a pointer. For a pressure sensing pointer, an elastic member is usually pressed by using a cartridge, then a pressure sensor is pressed, to sense stroke pressure for writing. The elastic member mainly presents a pressure gradient when a user performs writing and provides an elastic force returning the cartridge to an initial position.

It can be learned that after the pressure sensing pointer is used for a period of time, the elastic member may fail to provide an elastic force due to elastic fatigue or deformation of the elastic member. Consequently, the cartridge cannot be pushed back to the initial position, resulting in inaccurate sensing.

SUMMARY

To achieve the foregoing purposes, the present invention provides a pressure sensing pointer, including a housing, an electromagnetic unit, a cartridge, a pressing member, a first elastic member, a second elastic member, and a pressure sensing element. The housing has an accommodating space and a port, and the port is in communication with the accommodating space. The electromagnetic unit is located inside the accommodating space and includes a magnet and a coil, and the coil is wound outside the magnet. The cartridge is movably disposed at the port of the housing along an axial direction. The pressing member is movably disposed in the accommodating space along the axial direction, and is connected to the cartridge. The first elastic member is disposed inside the housing, and one end is fixed on the pressing member. The second elastic member is disposed inside the housing, one end abuts against the pressing member, the other end is fixedly disposed inside the accommodating space, and an amount of compression deformation of the second elastic member in the axial direction is greater than an amount of compression deformation of the first elastic member in the axial direction. The pressure sensing element is fixedly disposed inside the accommodating space, and the pressure sensing element faces toward the other end of the first elastic member.

DETAILED DESCRIPTION

Referring toFIG. 1,FIG. 1is a schematic sectional structural diagram of an embodiment of a pressure sensing pointer according to the present invention. The pressure sensing pointer herein is a passive or proactive electromagnetic induction indicator that has a circuit unit and that is used in combination with a digitizer tablet.

The pressure sensing pointer shown inFIG. 1includes a housing10, an electromagnetic unit20, a cartridge30, a pressing member40, a first elastic member50, a second elastic member60, and a pressure sensing element70.

Referring toFIG. 1, the housing10has an accommodating space11and a port12in communication with the accommodating space11. The electromagnetic unit20is located inside the accommodating space11, and includes a magnet21and a coil22winding around the magnet21. The cartridge30is movably disposed at the port12of the housing10along an axial direction X. The pressing member40is disposed inside the accommodating space11, and is in linkage connection to the cartridge30. The first elastic member50and the second elastic member60are disposed inside the accommodating space11, and one ends of the first elastic member50and the second elastic member60abut against the pressing member40. The other end of the second elastic member60is fixedly disposed inside the accommodating space11, and an amount of compression deformation of the second elastic member60in the axial direction X is greater than an amount of compression deformation of the first elastic member50. The pressure sensing element70is disposed inside the accommodating space11and faces toward the other end of the first elastic member50.

In this way, during use, the digitizer tablet emits electromagnetic energy. The pressure sensing pointer receives the electromagnetic energy emitted by the digitizer tablet. The coil22induces and couples the electromagnetic energy. Based on such an electromagnetic exchange process, a position of the pressure sensing pointer can be calculated, to accurately display handwriting. When the pressure sensing pointer acts on the digitizer tablet and applies pressure to the cartridge30, the cartridge30drives the pressing member40and applies pressure to the pressure sensing element70by using the first elastic member50. The pressure sensing element70senses the pressure of the cartridge30, and can further calculate handwriting pressure, to more accurately display the handwriting with a pressure change.

In this way, the digitizer tablet receives an electromagnetic signal emitted from the pressure sensing pointer, and calculates the position and stroke pressure of the pressure sensing pointer by using a proper calculation method based on a value and frequency of the electromagnetic signal emitted from the pressure sensing pointer and a pressure value measured by the pressure sensing element70, thereby generating the handwriting. In addition, the first elastic member50may provide pressure to obtain proper writing feeling. The second elastic member60can ensure that a position of the cartridge30can be returned to an initial position, and an induced electromagnetic signal is simultaneously returned to zero, thereby facilitating next writing sensing.

In an embodiment, continuing to refer toFIG. 1, the housing10is a hollow long-strip-shaped pen-type enclosure extending along the axial direction X, but is not limited thereto. Herein, one end of the housing10is open, and the other end is closed. The housing10is not limited thereto. Further, the accommodating space11of the housing10is divided into a plurality of segments111, to correspondingly accommodate the electromagnetic unit20, the cartridge30, and other internal components.

More specifically, further referring toFIG. 1, the accommodating space11of the housing10in this embodiment is sequentially divided into a first segment111A, a second segment111B, and a third segment111C from the port12to the other end. Herein, an inner diameter of the first segment111A is less than an inner diameter of the second segment111B, and the inner diameter of the second segment111B is less than an inner diameter of the third segment111C. In this way, the cartridge30is correspondingly located at a position of the first segment111A, the magnet21of the electromagnetic unit20is correspondingly located at a position of the second segment111B, and the coil22is correspondingly located at a position of the third segment111C.

In an embodiment, also referring toFIG. 1, the magnet21of the electromagnetic unit20includes a first magnet211, and the first magnet211is a hollow cylinder but is not limited thereto. The first magnet211has a through hole2111. The through hole2111threads through two ends of the first magnet211, and the first magnet211has an outer surface2112and an inner surface2113. An area surrounded by the inner surface2113defines the through hole2111. Herein, the first magnet211is accommodated in the second segment111B, and one end of the first magnet211abuts against a step between the second segment111B and the first segment111A. In addition, the first magnet211in this embodiment is made of a magnetic material.

Continuing to refer toFIG. 1, the coil22is wound outside the outer surface2112of the first magnet211. Herein, the coil22is accommodated inside the third segment111C. Herein, the coil22is limited by a step between the third segment111C and the second segment111B, and is therefore restricted inside the third segment111C.

Further, two ends of the coil22may be connected to a circuit unit C by using two conductive wires. The segments111of the accommodating space11may further include a fourth segment111D. The circuit unit C may be fixedly disposed inside the fourth segment111D of the accommodating space11. Herein, an inner diameter of the fourth segment111D is greater than the inner diameter of the third segment111C, and therefore the circuit unit C is restricted inside the fourth segment111D.

Referring toFIG. 1, in an embodiment, the cartridge30is a long-rod-shaped structure. Herein, the cartridge30has a tip end31and a combination end32that are opposite to each other. The tip end31has a tip contact surface311. The tip end31of the cartridge30extends from the port12, and is used for touch or writing by using the tip contact surface311. The combination end32is located inside the accommodating space11and is in linkage connection to the pressing member40.

Continuing to refer toFIG. 1, in an embodiment, the pressing member40is a stepped cylinder. Herein, the pressing member40has a first section41and a second section42. An outer diameter of the first section41is greater than an outer diameter of the second section42, and a step exists due to a difference between the outer diameters of the first section41and the second section42. Herein, the first section41of the pressing member40has a first combination portion411. The combination end32of the cartridge30is detachably combined with the first combination portion411of the pressing member40.

Further, in an embodiment, the combination end32of the cartridge30has a head section321, a neck section322, and a body section323that are sequentially connected. Herein, the head section321is a half-spherical structure, the head section321is smoothly necked down to the neck section322, and the neck section322gradually expands and becomes the body section323. The first combination portion411of the pressing member40is a groove. The shape of an inner peripheral surface of the first combination portion411corresponds to the shape of an outer profile of the head section321, the neck section322, and the body section323of the combination end32of the cartridge30. In this way, the cartridge30is detachably assembled to the pressing member40due to engagement of the combination end32with the first combination portion411, so that when the cartridge30wears or deforms, a user replaces the cartridge30with a required cartridge30by himself/herself, thereby replacing the cartridge30and maintaining best writing feeling.

Also referring toFIG. 1, the first elastic member50is disposed inside the accommodating space11, one end of the first elastic member50is fixed on the pressing member40, and the other end faces toward the pressure sensing element70. In this way, when the cartridge30is pressed due to a writing action, the cartridge30drives the pressing member40to press the pressure sensing element70, so that the pressure sensing element70senses writing pressure. Herein, the second section42of the pressing member40has a second combination portion421. The second combination portion421is a groove, and the first elastic member50is fixedly embedded in the second combination portion421.

Further, continuing to refer toFIG. 1, in an embodiment, the first elastic member50has a first end51and a second end52that are opposite to each other. The first end51abuts against the pressing member40, and the second end52faces toward the pressure sensing element70. An outer diameter of the first end51is different from an outer diameter of the second end52. More specifically, the outer diameter of the first end51is greater than the outer diameter of the second end52. A change between the outer diameter of the first end51and the outer diameter of the second end52may be a linear change, a curvature change, or a slope change, but is not limited thereto. Specifically, for the change from the first end51to the second end52, a smaller change within a unit distance is better. In other words, a smoother change from the first end51to the second end52is better, so that a change of a pressure gradient better satisfies an expected value of the user.

In this embodiment, both the first end51and the second end52are cylinder structures, and the first end51is connected to the second end52by using an inclined section53. Specifically, the first elastic member50may be made of a rubber material having an elastic restoring force, but is not limited thereto.

Referring toFIG. 1, in an embodiment, the second elastic member60is accommodated inside the accommodating space11, one end of the second elastic member60abuts against the pressing member40, and the other end is fixed. The second elastic member60may be a common coil spring, a conical spring, a disc spring, or another elastic material having a compression capability. Moreover, the second elastic member60may directly or indirectly abut against the electromagnetic unit20, to provide an elastic force in the axial direction X for the electromagnetic unit20. Herein, the second elastic member60is a coil spring that is sleeved on the second section42of the pressing member40and abuts against the first section41. In this way, the second elastic member60is also sleeved on an outer periphery of the first elastic member50, so that the first elastic member50is located at a central position on the second elastic member60, but is not limited thereto.

Continuing to refer toFIG. 1, the pressure sensing element70is fixedly disposed inside the accommodating space11and is electrically connected to the circuit unit C. Herein, the pressure sensing element70is located at a position facing toward the second end52of the first elastic member50. Further, a micro gap approaching to zero exists between the pressure sensing element70and the second end52of the first elastic member50.

Specifically, the micro gap between the pressure sensing element70and the first elastic member50is a gap between the pressure sensing element70and the first elastic member50when no force is applied to the cartridge30. Therefore, due to the micro gap approaching to zero, when no force is applied to the cartridge30, no force is generated between the cartridge30and the pressure sensing element70, thereby preventing the pressure sensing element70from being pressed in a normal state.

Referring toFIG. 2, when the pressure sensing pointer is used and applies pressure to the cartridge30, the cartridge30drives the pressing member40to be displaced along the axial direction X and toward the pressure sensing element70. In this case, the cartridge30simultaneously drives the first elastic member50to be displaced and compresses the second elastic member60, the first elastic member50is driven and is gradually displaced toward the pressure sensing element70, and the second elastic member60continuously accumulates an elastic force. When displacement amount of the first elastic member50exceeds a distance of the micro gap, the first elastic member50starts to push the pressure sensing element70and starts to provide the user with hand feeling of the pressure gradient. Meanwhile, pressure between the first elastic member50and the pressure sensing element70makes the first elastic member50deform and start accumulating an elastic force.

Next, when pressure continues to be applied to the cartridge30to make the first elastic member50continuously be in contact with the pressure sensing element70, the pressure sensing element70can sense stroke pressure and display handwriting with different stroke pressure through calculation. After the user releases the pressure applied to the cartridge30, the first elastic member50and the second elastic member60release the accumulated elastic forces, so that the pressing member40is pushed back to the initial position.

Further, referring toFIG. 3,FIG. 3is a change curve chart of load (x-axis) born by a cartridge and a pressure sensing value (y-axis) sensed by a pressure sensing element. A first sensing curve S1and a second sensing curve S2are available inFIG. 3. The first sensing curve S1is a sensing curve when no micro gap exists between the pressure sensing element70and a component pressing the pressure sensing element70or prepressure exists between the pressure sensing element70and the component pressing the pressure sensing element70. The second sensing curve S2is a sensing curve when the micro gap exists between the pressure sensing element70and the first elastic member50. It can be more clearly learned fromFIG. 3that when no micro gap exists between the pressure sensing element70and the component pressing the pressure sensing element70or prepressure exists between the pressure sensing element70and the component pressing the pressure sensing element70, as long as pressure is applied to the cartridge30, the pressure sensing element70can sense a pressure value. When the micro gap exists between the pressure sensing element70and the first elastic member50, pressure applied to the cartridge30cannot immediately cause the pressure sensing element70to sense a pressure value. Instead, the pressure sensing element70can measure a pressure value only when the pressure sensing element70is pressed by the first elastic member50after the first elastic member50is displaced by a distance of the micro gap when a force is applied to the cartridge30.

It can be learned that because a common pressure sensing element70has a pressure sensing range of a specific degree, when no force is applied to the cartridge30and the cartridge30does not apply prepressure to the pressure sensing element70, it can be ensured that the pressure sensing element70can provide a complete pressure sensing range during use, so that the pressure sensing element70maintains maximum compressible energy before pressure is applied to the pressure sensing element70, thereby increasing a permissible sensing range of the pressure sensing element70during use of the pressure sensing pointer.

In addition, the micro gap between the pressure sensing element70and the first elastic member50may alternatively means that the first elastic member50does not apply prepressure to the pressure sensing element70after assembly of the pressure sensing pointer is completed and when the user does not use the cartridge30for writing or touch. In this way, during assembly of the pressure sensing pointer, precision of applying prepressure does not need to be controlled, assembly difficulty can be significantly reduced, and assembly efficiency is increased.

In an embodiment, the pressure sensing element70may be an MEMS (micro-electro-mechanical system), but the pressure sensing element is not limited thereto. The pressure sensing element70may be a piezoelectric pressure sensing element performing sensing by using a piezoelectric effect, a capacitive pressure micro-sensor, an electromagnetic sensing element, or a resistive sensing element.

In this embodiment, the amount of compression deformation of the second elastic member60in the axial direction X is greater than the amount of compression deformation of the first elastic member50. Therefore, when elastic fatigue of the first elastic member50occurs as a result of material fatigue, material deterioration, or deformation, the second elastic member60can still provide power to the pressing member40for elastic recovery, thereby ensuring that the cartridge30can be used for writing each time under a same condition, and increasing use precision. In addition, after the pressure sensing pointer is assembled and before the pressure sensing pointer is used, the first elastic member50does not apply prepressure to the pressure sensing element70. That is, the first elastic member50is not in a pressed state when being in the normal state. In this way, a time at which elastic fatigue of the first elastic member50occurs can be delayed, thereby extending a service life of the first elastic member50.

In an embodiment, continuing to refer toFIG. 1, to further improve structural stability of internal mechanical parts, a fixed member80is further included. The fixed member80is fixedly disposed inside the accommodating space11of the housing10. Herein, the fixed member80has a concave hole81, a shaft hole82, and a limiting slot83. The concave hole81is in communication with the limiting slot83by using the shaft hole82. More specifically, the concave hole81may allow the pressing member40to be accommodated in the concave hole81and displaced along the axial direction X. An inner peripheral profile of the shaft hole82is the same as an outer peripheral profile of the cartridge30, and the shape and size of the limiting slot83corresponds to the shape and size of an outer peripheral profile of an end face of the first magnet211.

Based on this, the pressure sensing element70is fixed on one end of the concave hole81in the axial direction X. One end of the second elastic member60abuts against the end that is in the concave hole81and on which the pressure sensing element70is fixed, and the other end abuts against the pressing member40. Herein, the second elastic member60is a compression spring. Therefore, the second elastic member60stretches and abuts against the pressing member40in the normal state, so that in the normal state, the pressing member40abuts against the other end of the concave hole81in the axial direction X. The first elastic member50is located between the two ends of the concave hole81. The other end of the first magnet211abuts against the limiting slot83. The cartridge30is combined with the pressing member40after passing through the through hole2111of the first magnet211and the shaft hole82. In this way, each mechanical part inside the housing10is stably positioned to obtain a stable structural configuration.

Referring toFIG. 4,FIG. 4shows another embodiment of the present invention. A structural configuration in the embodiment ofFIG. 4is approximately the same as that of the embodiment ofFIG. 1andFIG. 2, and details are not described. Only differences are described below.

Referring toFIG. 4, in this embodiment, a head section321of a combination end32of a cartridge30is trapezoid and has two symmetrical bevels3211. The bevels3211gradually expands from the head section321to a neck section322, and the neck section322is necked down to a body section323. Based on a shape of the bevels3211, an assembly direction can be guided during assembly of the cartridge30, thereby improving assembly convenience. In addition, different types of a first elastic member50are shown in this embodiment. Herein, a first end51and a second end52of the first elastic member50are cylinder structures. An outer diameter of the first end51is greater than an outer diameter of the second end52, and the first end51is perpendicularly connected to the second end52, to form a T-shaped cylinder structure. In this embodiment, the first end51of the first elastic member50is in contact with a second section42of the pressing member40. The first end51of the first elastic member50may be bonded to the second section42of the pressing member40by using adhesive, a bolt or another fixing method. This is not limited thereto.

Referring toFIG. 5,FIG. 5shows another embodiment of the present invention. A structural configuration in the embodiment ofFIG. 5is approximately the same as those of the embodiments ofFIG. 1toFIG. 4, and details are not described. Only differences are described below.

Herein, a magnet21of an electromagnetic unit20further includes a second magnet212, and the electromagnetic unit20further includes a protection member23. The protection member23wraps the second magnet212. Herein, the protection member23has a head portion231and a shaft portion232. The second magnet212is completely wrapped with the head portion231, and the shaft portion232extends along a central axis of the second magnet212and forms a long-strip structure. In addition, the head portion231of the protection member23has a first engaging end2311, and the shaft portion232has a second engaging end2321. The second engaging end2321forms the shape corresponding to the shape of a first combination portion411of a pressing member40. In this way, the shaft portion232of the protection member23passes through a through hole2111of a first magnet211, and is combined with the pressing member40by using the second engaging end2321.

Continuing to refer toFIG. 5, in this embodiment, a cartridge30is of an over cap shape, and a combination end32of the cartridge30is of a groove shape. A combination end32forms the shape corresponding to the shape of the first engaging end2311of the protection member23. Based on this, the cartridge30is detachably sleeved on the head portion231of the protection member23by engaging the combination end32with the first engaging end2311. In this way, the cartridge30is combined with the protection member23, the second magnet212is wrapped with the protection member23, and the protection member23is combined with the pressing member40.

In this embodiment, the protection member23is made of a material having a buffer capability. For example, the protection member23may be made of ABS (acrylonitrile butadiene styrene) resin or a mixed material of ABS resin and PC (polycarbonate, PC) plastic. This is not limited thereto. The protection member23having a buffering capability wraps the second magnet212, to protect the second magnet212. In this way, the protection member23provides the buffering capability when a pressure sensing pointer suffers from an impact force, to protect the second magnet212from being damaged, and ensure that the second magnet212is not displaced and does not affect sensing.

When this embodiment is used, the cartridge30drives the protection member23to be displaced. The shaft portion232of the protection member23drives the pressing member40and the first elastic member50that is combined with the pressing member40to press the pressure sensing element70. The pressure sensing element70senses a force born by the cartridge30, thereby further performing calculation to simulate simulation stroke.

Referring toFIG. 5, in this embodiment, the head portion231of the protection member23abuts against a step between a first segment111A and a second segment111B. In this way, the protection member23is restricted inside the accommodating space11and cannot be easily removed from a port12.

In an embodiment, referring toFIG. 5, the second magnet212has a first end2121and a second end2122that are opposite to each other. An outer diameter of the first end2121is greater than an outer diameter of the second end2122, and the first end2121of the second magnet212is closer to the first magnet211relative to the second end2122. That is, the second end2122of the second magnet212is closer to the port12relative to the first end2121. Herein, the cartridge30is sleeved on a position on the protection member23corresponding to the second end2122of the second magnet212. In this way, because the size of the second end2122close to port12is less than that of the first end2121, the size of the cartridge30correspondingly wrapping the second end2122of the second magnet212is reduced. Based on this, the cartridge30of the pressure sensing pointer in this embodiment is closer to a digitizer tablet during use, thereby increasing precision and stability of coordinates and a pressure gradient of the cartridge30.

Referring toFIG. 6,FIG. 6shows another embodiment of the present invention. A structural configuration in the embodiment ofFIG. 6is approximately the same as those of the foregoing embodiments, and details are not described. Only differences are described below.

In this embodiment, an electromagnetic unit20includes a first magnet211and a coil22, and the first magnet211is a solid rod structure. The coil22is also wound outside an outer periphery of the first magnet211.

Herein, the pressure sensing pointer further includes a cartridge connection member90. The cartridge connection member90is accommodated inside an accommodating space11of the housing10. The cartridge connection member90is a hollow enclosure structure. The first magnet211and the coil22are fixedly accommodated inside the cartridge connection member90. One end of the cartridge connection member90is connected to a pressing member40, and the other end is connected to the cartridge30. In addition, the pressing member40is also combined with the first elastic member50, and a second elastic member60coils around the pressing member40, but is not limited thereto.

Specifically, an outer peripheral profile of the cartridge connection member90forms the shape corresponding to shapes of a second segment111B and a third segment111C, and the cartridge connection member90can be displaced inside the accommodating space11along the axial direction X. Moreover, a first section41of the pressing member40has a sleeve edge412. The cartridge connection member90is sleeved on the sleeve edge412, and the first magnet211is through-disposed and fixedly disposed inside the sleeve edge412.

Further, in this embodiment, a fixed member80is fixed at a fourth segment111D inside the accommodating space11, and is of a boss shape, so that the pressure sensing element70is fixed, and the second elastic member60is sleeved on and abuts against the fixed member80.

Herein, the cartridge connection member90has a combination portion91. The combination portion91is a groove formed corresponding to the shape of a combination end32of the cartridge30. The cartridge30in this embodiment can be replaced due to that the combination end32is detachably connected to the combination portion91of the cartridge connection member90.

In this embodiment, when pressure is applied to the cartridge30for writing, the cartridge30drives the cartridge connection member90to be displaced, the cartridge connection member90drives the pressing member40to press the first elastic member50, the second elastic member60, and the pressure sensing element70, and the pressure sensing element70senses writing pressure and accurately presents the writing pressure.

Referring toFIG. 7,FIG. 7shows another embodiment of the present invention. A structural configuration in the embodiment ofFIG. 7is approximately the same as that of the embodiment ofFIG. 6, and details are not described. Only differences are described below.

A difference between this embodiment and the embodiment ofFIG. 6is the shape of a first elastic member50. In this embodiment, the first elastic member50also has a first end51and a second end52, and an outer diameter of the first end51is greater than an outer diameter of the second end52. Herein, the first elastic member50further has a connection section54. The connection section54is connected to the first end51, and an outer diameter of the connection section54is less than the outer diameter of the first end51. The connection section54of the first elastic member50is engaged inside a second combination portion421of a pressing member40. Based on this, in this embodiment, a purpose or an effect the same as that of the foregoing embodiments is also achieved by using the first elastic member50having the different form.

Referring toFIG. 8,FIG. 8shows another embodiment of the present invention. A structural configuration in the embodiment ofFIG. 8is approximately the same as that of the embodiment ofFIG. 7, and details are not described. Only differences are described below.

Differences between this embodiment and the embodiment ofFIG. 7are a structural configuration of an electromagnetic unit20and a shape of a cartridge30. In this embodiment, the electromagnetic unit20includes a first magnet211, a coil22, a second magnet212, and a protection member23. Both the first magnet211and the second magnet212are solid structures. The first magnet212and the coil22are accommodated inside a cartridge connection member90. The protection member23is fixed on the cartridge connection member90after wrapping the second magnet212. The cartridge30is detachably sleeved on the protection member23. Based on this, in this embodiment, a purpose or an effect the same as that of the foregoing embodiments is also achieved by using the electromagnetic unit20having the different configuration and the cartridge30having the different form.

In some embodiments, the shape of the first elastic member50may vary provided that the first end51is greater than the second end52, and variations thereof are shown inFIG. 9toFIG. 11, but are not limited thereto. Provided that the first end51of the first elastic member50is greater than the second end52, better writing feeling can be provided.

In addition, referring toFIG. 12,FIG. 12shows another implementation of a pressing member40. Herein, a first section41of the pressing member40further has an operation notch413, and the operation notch413threads through a first combination portion411. With the operation notch413, a user can more easily replace a cartridge30or a protection member23engaged inside the first combination portion411, thereby improving convenience.