Electromagnetic pen

Abstract

This utility model relates to an electromagnetic pen. The electromagnetic pen includes: a pen body; a pen tip disposed inside the pen body and capable of sliding axially, the lower end of the pen tip extending beyond the lower end of the pen body, and a switch structure disposed above the pen tip; an LC parallel resonant circuit disposed on a circuit board inside the pen body and including a first capacitor and a first inductor connected in parallel; and a second capacitor, the first end of which is electrically connected to one end of the first capacitor or the first inductor of the LC parallel resonant circuit, and the second end of which is electrically connected to the switch structure; wherein, when the pen tip slides upward axially, the switch structure is activated, so that the second end of the second capacitor is electrically connected to the other end of the first capacitor or the first inductor of the LC parallel resonant circuit through the activated switch structure, thereby connecting the second capacitor in parallel with the LC parallel resonant circuit. This utility model's electromagnetic pen facilitates the adjustment of the original electrical parameters of the electromagnetic pen and improves the user experience.

Description

Technical Field

[0001] This utility model relates to the field of electromagnetic pens. Background Technology

[0002] An electromagnetic pen is an input device that interacts with an electromagnetic touchscreen by emitting electromagnetic signals based on the electromagnetic induction effect. The pen contains a pressure sensor. When the pen tip is subjected to force and moves, the electrical parameters of the pressure sensor change. The greater the force applied to the pen tip, the greater the change in the sensor's electrical parameters. When the change in the sensor's electrical parameters reaches a specific threshold, the writing appears on the electromagnetic induction board; this process is called ink dispensing.

[0003] Since the electrical parameters of the electronic components of the pressure sensor change linearly, and in order to ensure the user's feel, it is usually desirable to use a light force to make the electromagnetic pen dispense ink. This results in a small change in the electrical parameters of the pressure sensor when the electromagnetic pen dispenses ink, which is not conducive to the adjustment of the original electrical parameters.

[0004] Furthermore, the electrical parameters of the pressure sensor's electronic components are easily affected by environmental factors (such as temperature and humidity) and mechanical factors (such as material deformation), and other electronic components within the electromagnetic pen also participate in the entire process of electrical parameter changes. Therefore, to avoid misjudgment, the specific threshold for ink dispensing by the electromagnetic pen is usually set relatively high. In other words, the electromagnetic pen only dispenses ink when the electrical parameters of the pressure sensor change significantly.

[0005] Currently, for electromagnetic pens using capacitive pressure sensors, users need to apply significant pressure to the pen tip to cause a substantial change in the capacitance of the voltage-changing capacitor inside the pen. For electromagnetic pens using inductive pressure sensors, users need to allow the pen tip to travel a longer distance so that the magnetic core moves a greater distance relative to the coil, thus causing a larger change in inductance. Both applying significant pressure to the pen tip and ensuring a long travel distance negatively impact the user's writing experience.

[0006] The information disclosed in the background section of this utility model is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0007] The purpose of this invention is to provide an electromagnetic pen that overcomes the above-mentioned shortcomings of the prior art. This invention can solve the problem that existing electromagnetic pens require applying greater pressure to the pen tip or making the pen tip have a longer stroke in order to dispense ink. It not only facilitates the adjustment of the original electrical parameters of the electromagnetic pen, but also improves the user experience.

[0008] To achieve the above objectives, this utility model provides an electromagnetic pen, comprising: a pen body; a pen core disposed inside the pen body and capable of sliding axially, the lower end of the pen core extending beyond the lower end of the pen body, and a switch structure disposed above the pen core; an LC parallel resonant circuit disposed on a circuit board inside the pen body and including a first capacitor and a first inductor connected in parallel; and a second capacitor, the first end of which is electrically connected to one end of the first capacitor or the first inductor of the LC parallel resonant circuit, and the second end of which is electrically connected to the switch structure; wherein, when the pen core slides upward axially, the switch structure is turned on, so that the second end of the second capacitor is electrically connected to the other end of the first capacitor or the first inductor of the LC parallel resonant circuit through the turned-on switch structure, thereby making the second capacitor connected in parallel with the LC parallel resonant circuit.

[0009] In the aforementioned electromagnetic pen, the switch structure includes a conductive part, which is fixedly disposed at the upper end of the pen refill; the second end of the second capacitor is electrically connected to the conductive part; the first inductor includes a magnetic core and a coil wound on the magnetic core, the magnetic core being fixedly installed inside the pen body and coaxially disposed outside the pen refill.

[0010] In the aforementioned electromagnetic pen, the first capacitor includes: a variable capacitor with a first contact pin disposed on its upper side, the first contact pin being electrically connected to one end of the coil; and a conductive sheet located below the variable capacitor, the conductive sheet contacting the lower surface of the variable capacitor and forming an electrode of the first capacitor together with the lower electrode of the variable capacitor; a second contact pin disposed on the upper side of the conductive sheet, the second contact pin having a predetermined lateral distance from the variable capacitor, the second contact pin being electrically connected to the other end of the coil.

[0011] In the aforementioned electromagnetic pen, the first capacitor includes: a variable capacitor with a first contact pin disposed on its upper side, the first contact pin being electrically connected to one end of the coil; and a conductive sheet located below the variable capacitor and selectively contacting the lower surface of the variable capacitor. When the conductive sheet is not in contact with the lower surface of the variable capacitor, the conductive sheet forms one electrode of the first capacitor; when the conductive sheet is in contact with the lower surface of the variable capacitor, the conductive sheet and the lower electrode of the variable capacitor together form one electrode of the first capacitor. A second contact pin is disposed on the upper side of the conductive sheet, the second contact pin having a predetermined lateral distance from the variable capacitor, and the second contact pin being electrically connected to the other end of the coil.

[0012] In the aforementioned electromagnetic pen, the conductive sheet is located above the conductive part and has a predetermined longitudinal gap with the conductive part; when the pen tip slides upward along the axial direction, the conductive part slides upward along the axial direction with the pen tip and can contact the conductive sheet, thereby turning on the switch structure; when the pen tip continues to slide upward along the axial direction, the capacitance value of the first capacitor increases under the pressure of the conductive part.

[0013] In the aforementioned electromagnetic pen, the switch structure further includes a conductive elastic element, the upper part of which is disposed on the circuit board, and the lower part of which is sleeved on and in contact with the outer wall of the conductive part. The conductive elastic element can apply a restoring force to the conductive part so that the pen tip can be reset after sliding. The second terminal of the second capacitor is electrically connected to the conductive elastic element.

[0014] In the aforementioned electromagnetic pen, the cross-section of the conductive part is shaped like a "U" and includes a first part and a second part, the second part extending radially outward from the lower edge of the first part. The lower part of the conductive elastic element is fitted onto the outer wall of the first part of the conductive part, and the lower end of the lower part of the conductive elastic element abuts against the upper surface of the second part of the conductive part.

[0015] According to another exemplary embodiment of the present invention, the first inductor includes: a magnetic core, which is coaxially disposed on the pen refill and is capable of sliding axially with the pen refill; and a coil, which is wound on a winding skeleton disposed inside the pen body and located outside the magnetic core, the coil being coaxially disposed with the magnetic core; wherein, one end of the first capacitor is electrically connected to one end of the coil, and the other end of the first capacitor is electrically connected to the other end of the coil.

[0016] In the aforementioned electromagnetic pen, the switch structure includes: a conductive part fixedly disposed at the upper end of the magnetic core; and a PCB board located above the conductive part and having a broken copper foil disposed thereon; wherein, the second end of the second capacitor is electrically connected to the copper foil on the PCB board, and when the pen tip slides upward along the axial direction, the conductive part enables the broken copper foil to conduct, thereby enabling the switch structure to conduct.

[0017] The electromagnetic pen described above further includes a reset device, which is sleeved on the outer wall of the conductive part and its upper end presses against the lower surface of the PCB board. The reset device can apply a reset force to the conductive part so that the magnetic core can drive the pen core to reset after sliding with the pen core.

[0018] The electromagnetic pen of this invention can cause the second capacitor to be connected in parallel with the LC parallel resonant circuit in the electromagnetic pen when the pen tip is lightly pressed. This causes a large change in the electrical parameters of the pressure sensor of the electromagnetic pen, thereby reaching the specific threshold for ink dispensing. This avoids the problem of needing to apply a large pressure to the pen tip or make the pen tip have a long stroke to dispense ink. This not only facilitates the adjustment of the original electrical parameters of the electromagnetic pen, but also improves the user experience.

[0019] The device of this invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and subsequent embodiments incorporated herein, which together serve to explain the particular principles of this invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the electromagnetic pen according to the embodiment of this utility model.

[0021] Figure 2 This is an equivalent circuit diagram of the internal structure of the electromagnetic pen according to the embodiment of this utility model.

[0022] Figure 3 This is a schematic diagram of the structure of an electromagnetic pen according to another exemplary embodiment of the present invention.

[0023] Figure 4 This is an equivalent circuit diagram of the internal structure of an electromagnetic pen according to another exemplary embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the PCB board structure of an electromagnetic pen according to another exemplary embodiment of the present invention.

[0025] It should be understood that the accompanying drawings are not drawn to scale, but rather illustrate various features that are presented in a slightly simplified manner to explain the basic principles of the present invention. In the accompanying drawings of this invention, the same reference numerals denote the same or equivalent parts of the invention. Detailed Implementation

[0026] Reference will now be made in detail to various embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. Although the present invention will be described in conjunction with exemplary embodiments, it will be understood that this specification is not intended to limit the present invention to those exemplary embodiments. On the contrary, the present invention is intended to cover not only the exemplary embodiments of the present invention, but also various alternatives, modifications, equivalents, and other embodiments included within the spirit and scope of the present invention as defined in the appended claims.

[0027] The following is combined with Figures 1 to 5 The electromagnetic pen of the present invention will be described.

[0028] Figure 1 This is a schematic diagram of the structure of the electromagnetic pen according to the embodiment of this utility model. Figure 2 This is an equivalent circuit diagram of the internal structure of the electromagnetic pen according to the embodiment of this utility model.

[0029] According to an exemplary embodiment of this utility model, a capacitive pressure sensor is used. Combined with... Figure 1 and Figure 2 As shown, the electromagnetic pen of the exemplary embodiment of this utility model includes: a pen body (not shown in the figure), a pen core 200, an LC parallel resonant circuit, and a second capacitor 400.

[0030] The pen body has an internal circuit board 110 for arranging circuits. A pen refill 200 is disposed inside the pen body and can slide axially within it. The lower end of the pen refill 200 extends beyond the lower end of the pen body to facilitate writing on the electromagnetic induction board. A switch structure 500 is disposed above the pen refill 200. An LC parallel resonant circuit is disposed on the circuit board 110 inside the pen body and includes a first capacitor 310 and a first inductor 320 connected in parallel. The first terminal of a second capacitor 400 is electrically connected to one end of the first capacitor 310 or the first inductor 320 of the LC parallel resonant circuit, and the second terminal of the second capacitor 400 is electrically connected to the switch structure 500. When the pen refill 200 slides upward axially, the switch structure 500 is turned on, so that the second terminal of the second capacitor 400 is electrically connected to the other end of the first capacitor 310 or the first inductor 320 of the LC parallel resonant circuit through the turned-on switch structure 500, thereby connecting the second capacitor 400 in parallel with the LC parallel resonant circuit.

[0031] In other words, when the pen tip 200 slides upward along the axial direction, the switch structure 500 above the pen tip 200 can be turned on, so that the second capacitor 400 is connected in parallel with the LC parallel resonant circuit composed of the first capacitor 310 and the first inductor 320, thereby causing a large change in the capacitance value in the LC parallel resonant circuit. Thus, when the user uses the electromagnetic pen, by lightly pressing the pen tip, the second capacitor is connected in parallel with the LC parallel resonant circuit in the electromagnetic pen, causing a large change in the electrical parameters of the electromagnetic pen's pressure sensor, thereby reaching the specific threshold for ink dispensing. This avoids the problem of needing to apply excessive pressure to the pen tip or have a long stroke to dispense ink, which not only facilitates the adjustment of the electromagnetic pen's original electrical parameters but also improves the user experience.

[0032] According to an exemplary embodiment of the present invention, in conjunction with Figure 1 and Figure 2As shown, the switch structure 500 includes a conductive part 510, which is fixedly disposed on the upper end of the pen refill 200. The second end of the second capacitor 400 is electrically connected to the conductive part 510. The first inductor 320 includes a magnetic core 321 and a coil 322 wound on the magnetic core 321. The magnetic core 321 is fixedly installed inside the pen body and coaxially disposed outside the pen refill 200. The magnetic core 321 and the pen refill 200 are in a clearance fit, meaning that a small gap, or even zero gap, can be left between the inner wall of the magnetic core 321 and the outer wall of the pen refill 200. This ensures that when the pen refill 200 slides upward axially under pressure, it will not cause the magnetic core 321 to slide upward together, and it will not be affected by the frictional resistance of the magnetic core 321. Furthermore, the pen refill 200 is less prone to deformation when subjected to radial force.

[0033] Further, the first capacitor 310 includes a variable capacitor 311 and a conductive sheet 312. A first contact pin 313 is disposed on the upper side of the variable capacitor 311, and the first contact pin 313 is electrically connected to one end of the coil 322. The conductive sheet 312 is located below the variable capacitor 311. Preferably, the conductive sheet 312 can directly contact the lower surface of the variable capacitor 311 and together with the lower electrode of the variable capacitor 311, form an electrode of the first capacitor 310. The conductive sheet 312 can also selectively contact the lower surface of the variable capacitor 311. That is, in the normal state, the conductive sheet 312 and the lower surface of the variable capacitor 311 can be separated by a spacer of a specific material so that the conductive sheet 312 does not contact the lower surface of the variable capacitor 311. In this case, the conductive sheet 312 forms an electrode of the first capacitor 310. When the conductive sheet 312 is subjected to upward pressure, it can contact the lower surface of the variable capacitor 311. At this time, the conductive sheet 312 and the lower plate of the variable capacitor 311 together form one plate of the first capacitor 310. A second contact pin 314 is provided on the upper side of the conductive sheet 312. The second contact pin 314 and the variable capacitor 311 have a predetermined lateral distance, so that the second contact pin 314 will not directly contact the variable capacitor 311 to conduct electricity. The second contact pin 314 is electrically connected to the other end of the coil 322. With the above structural arrangement, the two ends of the first capacitor 310 can be electrically connected to the two ends of the coil 322, so that the first capacitor 310 and the first inductor 320 form an LC parallel resonant circuit.

[0034] Furthermore, the conductive sheet 312 is located above the conductive portion 510, and there is a predetermined longitudinal gap between the conductive sheet 312 and the conductive portion 510, so that the conductive sheet 312 and the conductive portion 510 are not conductive in the normal state. When the pen refill 200 slides upward along the axial direction, the conductive portion 510 slides upward along the axial direction with the pen refill and can contact the conductive sheet 312, so that the conductive sheet 312 and the conductive portion 510 are conductive, thereby making the second end of the second capacitor 400 electrically connected to the conductive portion 510 electrically connected to the other end of the first capacitor 310 or the first inductor 320, so that the second capacitor 400 is connected in parallel with the LC parallel resonant circuit.

[0035] In other words, when the user uses the electromagnetic pen, the pen tip 200 slides upward along the axis under pressure, causing the conductive part 510 above the pen tip 200 to slide upward along the axis. When the conductive part 510 contacts the conductive sheet 312, the switch structure 500 is turned on, so that the second capacitor 400 is connected in parallel with the LC parallel resonant circuit, thereby causing a large change (increase) in the capacitance value of the LC parallel resonant circuit, thus reaching the specific threshold for ink dispensing of the electromagnetic pen.

[0036] Furthermore, as the pressure on the pen tip 200 increases and it continues to slide upwards axially, the capacitance of the first capacitor 310 increases under the pressure of the conductive part 510. This increases the overall capacitance of the LC parallel resonant circuit. The greater the pressure on the pen tip 200, the greater the pressure on the first capacitor 310, and the greater the change (increase) in the capacitance of the first capacitor 310. In this way, the electromagnetic induction plate can output handwriting adjusted according to the force applied to the pen tip 200, based on changes in the electrical parameters of the electromagnetic pen.

[0037] Furthermore, the switch structure 500 also includes a conductive elastic element 520. The upper part of the conductive elastic element 520 is disposed on the circuit board 110, and the lower part of the conductive elastic element 520 is sleeved on and in contact with the outer wall of the conductive part 510. The conductive elastic element 520 can apply a reset force to the conductive part 510, so that the conductive part 510 can be reset after sliding with the pen refill 200, and drive the pen refill 200 to reset. The second terminal of the second capacitor 400 is electrically connected to the conductive elastic element 520.

[0038] Furthermore, the conductive portion 510 has a cross-section shaped like a "U" and includes a first portion 511 and a second portion 512, with the second portion 512 extending radially outward from the lower edge of the first portion 511. The lower part of the conductive elastic member 520 is sleeved on the outer wall of the first portion 511 of the conductive portion 510, and the lower end of the lower part of the conductive elastic member 520 presses against the upper surface of the second portion 512 of the conductive portion 510 to apply a downward axial restoring force to the conductive portion 510, thereby enabling the conductive portion 510 to return to its original position after sliding with the pen refill 200, and driving the pen refill 200 to return to its original position.

[0039] Preferably, in this embodiment, the conductive part 510 is made of a conductive metal. However, it should be understood that the conductive part 510 can also be made of other conductive materials, as long as they meet the usage requirements of this utility model.

[0040] Figure 3 This is a schematic diagram of the structure of an electromagnetic pen according to another exemplary embodiment of the present invention. Figure 4 This is an equivalent circuit diagram of the internal structure of an electromagnetic pen according to another exemplary embodiment of the present invention. Figure 5 This is a schematic diagram of the PCB board structure of an electromagnetic pen according to another exemplary embodiment of the present invention.

[0041] According to another exemplary embodiment of the present invention, the electromagnetic pen uses an inductive pressure sensor. Combined with... Figure 3 and Figure 4 As shown, the first inductor 320 includes a magnetic core 321 and a coil 322. The magnetic core 321 is coaxially disposed on the pen refill 200 and can slide axially with the pen refill 200. The coil 322 is wound on a winding frame 120 disposed inside the pen body and is located outside the magnetic core 321, with the coil 322 and the magnetic core 321 being coaxially disposed. One end of the first capacitor 310 is electrically connected to one end of the coil 322, and the other end of the first capacitor 310 is electrically connected to the other end of the coil 322.

[0042] Furthermore, the switch structure 500 includes a conductive part 510 and a PCB board 530. The conductive part 510 is fixedly disposed on the upper end of the magnetic core 321. The PCB board 530 is located above the conductive part 510 and has a broken copper foil 531 disposed thereon. The second end of the second capacitor 400 is electrically connected to the copper foil 531 on the PCB board 530, and when the pen refill 200 slides upward along the axial direction, the conductive part 510 can make the broken copper foil 531 conductive, thereby turning on the switch structure 500.

[0043] Furthermore, the PCB board 530 has solder pads 532 at both ends, which are electrically connected to the second terminal of the second capacitor 400 and the other terminal of the first capacitor 310 or the first inductor 320 of the LC parallel resonant circuit. When the switch structure 500 is turned on, the second terminal of the second capacitor 400 is electrically connected to the other terminal of the first capacitor 310 or the first inductor 320 of the LC parallel resonant circuit through the turned-on switch structure 500, thereby making the second capacitor 400 connected in parallel with the LC parallel resonant circuit.

[0044] In other words, when the user uses the electromagnetic pen, the pen tip 200 slides upward along the axis under pressure, causing the conductive part 510 above the pen tip 200 to slide upward along the axis. When the conductive part 510 contacts the copper foil 531 on the PCB board 530, the copper foil 531 becomes conductive, thereby turning on the switch structure 500. This causes the second capacitor 400 to be connected in parallel with the LC parallel resonant circuit, resulting in a significant change (reduction) in the resonant frequency of the LC parallel resonant circuit, thus achieving the specific threshold for ink dispensing from the electromagnetic pen.

[0045] Furthermore, in this embodiment, the conductive part 510 is made of conductive silicone particles. When the pen tip 200 slides upward along the axial direction, the conductive silicone particles make the copper foil 531 conductive, thereby turning on the switch structure 500. Since the conductive silicone particles are a soft material, when the pressure on the pen tip 200 increases, it can continue to slide upward along the axial direction, driving the magnetic core 321 to continue sliding upward. This causes the resonant frequency of the LC parallel resonant circuit to continue to change (decrease). Moreover, the greater the pressure on the pen tip 200, the farther the magnetic core 321 moves with the pen tip 200, and the greater the change in resonant frequency. In this way, the electromagnetic induction plate can output writing that is adjusted according to the magnitude of the force on the pen tip 200 based on the changes in the electrical parameters of the electromagnetic pen.

[0046] Furthermore, the electromagnetic pen of this invention further includes a reset device 600. The reset device 600 is sleeved on the outer wall of the conductive part 510 and its upper end presses against the lower surface of the PCB board 530. The reset device 600 can apply a reset force to the conductive part 510 so that the magnetic core 321 can be reset after sliding with the pen tip 200, and drive the pen tip 200 to reset. Specifically, in this exemplary embodiment, the reset device 600 is a spring.

[0047] The working principle of the electromagnetic pen according to the present invention will be explained below with reference to the accompanying drawings.

[0048] For the electromagnetic pen using a capacitive pressure sensor in an exemplary embodiment of this utility model, when a user writes on the electromagnetic induction board, the user can lightly press the pen tip 200, causing the pen tip 200 to slide upwards axially under pressure, and driving the conductive part 510 above the pen tip 200 to slide upwards axially. When the conductive part 510 contacts the conductive sheet 312, the switch structure 500 is turned on, so that the second capacitor 400 is connected in parallel with the LC parallel resonant circuit composed of the first capacitor 310 and the first inductor 320, thereby causing a large change (increase) in the capacitance value in the LC parallel resonant circuit, thus reaching the specific threshold for ink dispensing of the electromagnetic pen. At this time, the user can write on the electromagnetic induction board.

[0049] When the user increases the writing pressure, the pen tip 200 experiences increased pressure and continues to slide upwards axially. This causes the capacitance of the first capacitor 310 to increase under the pressure of the conductive part 510, thereby increasing the overall capacitance of the LC parallel resonant circuit. Furthermore, the greater the pressure on the pen tip 200, the greater the pressure on the first capacitor 310, and the greater the change (increase) in the capacitance of the first capacitor 310. In this way, the electromagnetic induction plate can output handwriting adjusted according to the user's writing pressure based on changes in the electromagnetic pen's electrical parameters.

[0050] For an electromagnetic pen using an inductive pressure sensor in another exemplary embodiment of this utility model, when a user writes on the electromagnetic induction board, the user can lightly press the pen tip 200, causing the pen tip 200 to slide upwards axially under pressure, and driving the conductive part 510 above the pen tip 200 to slide upwards axially. When the conductive part 510 contacts the copper foil 531 on the PCB board 530, the copper foil 531 conducts, causing the switch structure 500 to conduct, thereby connecting the second capacitor 400 in parallel with the LC parallel resonant circuit composed of the first capacitor 310 and the first inductor 320. This causes a significant change (reduction) in the resonant frequency of the LC parallel resonant circuit, reaching a specific threshold for ink dispensing by the electromagnetic pen. At this time, the user can write on the electromagnetic induction board.

[0051] When the user increases the writing pressure, because the conductive silicone particles in the conductive part 510 are made of soft material, the pen tip 200 experiences increased pressure and continues to slide upwards axially, causing the magnetic core 321 to slide upwards as well. This causes the resonant frequency of the LC parallel resonant circuit to continue to change (decrease). Furthermore, the greater the pressure on the pen tip 200, the farther the magnetic core 321 moves with the pen tip 200, and the greater the change in resonant frequency. In this way, the electromagnetic induction plate can output handwriting adjusted according to the user's writing pressure based on changes in the electromagnetic pen's electrical parameters.

[0052] Through the above exemplary implementation scheme, the advantages of this utility model are: when the pen refill is lightly pressed, the second capacitor can be connected in parallel with the LC parallel resonant circuit in the electromagnetic pen, so that the electrical parameters of the pressure sensor of the electromagnetic pen have a large change, thereby reaching the specific threshold for ink dispensing of the electromagnetic pen. This avoids the problem of needing to apply a large pressure to the pen refill or make the pen refill have a long stroke to dispense ink. This not only facilitates the adjustment of the original electrical parameters of the electromagnetic pen, but also improves the user experience.

[0053] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it will be apparent that many modifications and variations can be made in light of the foregoing teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and its practical application, thereby enabling those skilled in the art to make and utilize various exemplary embodiments of the invention, as well as their different alternatives and modifications. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. An electromagnetic pen, characterized by, include: Pen style; The pen refill is disposed inside the pen body and can slide along the axis. The lower end of the pen refill extends out of the lower end of the pen body, and a switch structure is disposed above the pen refill. An LC parallel resonant circuit is disposed on a circuit board inside the pen body and includes a first capacitor and a first inductor connected in parallel; and The second capacitor has its first terminal electrically connected to one end of the first capacitor or the first inductor of the LC parallel resonant circuit, and its second terminal electrically connected to the switch structure. When the pen tip slides upward along the axial direction, the switch structure can be turned on, so that the second end of the second capacitor is electrically connected to the other end of the first capacitor or the first inductor of the LC parallel resonant circuit through the turned-on switch structure, thereby making the second capacitor and the LC parallel resonant circuit in parallel.

2. The electromagnetic pen of claim 1, wherein, The switch structure includes a conductive part, which is fixedly disposed at the upper end of the pen refill; The second terminal of the second capacitor is electrically connected to the conductive part; The first inductor includes a magnetic core and a coil wound on the magnetic core, the magnetic core being fixedly mounted inside the pen body and coaxially disposed outside the pen refill.

3. The electromagnetic pen of claim 2, wherein, The first capacitor includes: A variable capacitor, having a first contact pin disposed on its upper side, the first contact pin being electrically connected to one end of the coil; and A conductive sheet is located below the variable capacitor. The conductive sheet is in contact with the lower surface of the variable capacitor and together with the lower plate of the variable capacitor, forms one plate of the first capacitor. A second contact pin is provided on the upper side of the conductive sheet. The second contact pin has a predetermined lateral distance from the variable capacitor. The second contact pin is electrically connected to the other end of the coil.

4. The electromagnetic pen of claim 2, wherein, The first capacitor includes: A variable capacitor, having a first contact pin disposed on its upper side, the first contact pin being electrically connected to one end of the coil; and A conductive sheet is located below the variable capacitor and selectively contacts the lower surface of the variable capacitor. When the conductive sheet is not in contact with the lower surface of the variable capacitor, the conductive sheet forms one electrode of the first capacitor. When the conductive sheet contacts the lower surface of the variable capacitor, the conductive sheet and the lower electrode of the variable capacitor together form one electrode of the first capacitor. A second contact pin is provided on the upper side of the conductive sheet. The second contact pin has a predetermined lateral distance from the variable capacitor. The second contact pin is electrically connected to the other end of the coil.

5. The electromagnetic pen according to claim 3 or 4, characterized in that, The conductive sheet is located above the conductive part and has a predetermined longitudinal gap with the conductive part; When the pen tip slides upward along the axial direction, the conductive part slides upward along the axial direction with the pen tip and can contact the conductive sheet, thereby turning on the switch structure; As the pen tip continues to slide upward along the axial direction, the capacitance of the first capacitor increases under the pressure of the conductive part.

6. The electromagnetic pen of claim 4, wherein, The switching structure further includes: A conductive elastic element has its upper part disposed on the circuit board and its lower part sleeved on and in contact with the outer wall of the conductive part. The conductive elastic element can apply a restoring force to the conductive part so that the pen tip can be reset after sliding. The second terminal of the second capacitor is electrically connected to the conductive elastic element.

7. The electromagnetic pen of claim 5, wherein, The cross-section of the conductive part is configured as a "U" shape and includes a first part and a second part, wherein the second part extends radially outward from the lower edge of the first part; The lower part of the conductive elastic element is sleeved on the outer wall of the first part of the conductive part, and the lower end of the lower part of the conductive elastic element abuts against the upper surface of the second part of the conductive part.

8. The electromagnetic pen of claim 1, wherein, The first inductor includes: A magnetic core, coaxially disposed on the pen refill and capable of sliding axially with the pen refill; and A coil is wound around a winding skeleton provided inside the pen body and located outside the magnetic core, the coil being coaxially arranged with the magnetic core; Wherein, one end of the first capacitor is electrically connected to one end of the coil, and the other end of the first capacitor is electrically connected to the other end of the coil.

9. The electromagnetic pen of claim 8, wherein, The switch structure includes: A conductive part, the conductive part being fixedly disposed at the upper end of the magnetic core; and A PCB board, located above the conductive part and provided with a broken copper foil; The second terminal of the second capacitor is electrically connected to the copper foil on the PCB board, and when the pen tip slides upward along the axial direction, the conductive part can make the disconnected copper foil conduct, thereby making the switch structure conduct.

10. The electromagnetic pen of claim 9, wherein, It further includes: A reset device is sleeved on the outer wall of the conductive part and its upper end presses against the lower surface of the PCB board. The reset device can apply a reset force to the conductive part so that the magnetic core can drive the pen core to reset after sliding with the pen core.

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