Sensors and electromagnetic pens

Abstract

This disclosure relates to a sensor and an electromagnetic pen, wherein the sensor includes a flexible circuit board, a variable capacitor, and a flexible conductor. The variable capacitor is disposed on the flexible circuit board and includes a first electrode and a second electrode. The flexible circuit board has a first side surface, and the first and second electrodes are located on the first side surface, with a capacitance between the first and second electrodes. The flexible conductor is disposed facing the first side surface. Under the action of a measured pressure, the flexible conductor contacts the first side surface and changes the contact area with the first side surface. The contact area is mapped to the capacitance value of the variable capacitor, which is used to characterize the pressure value of the measured pressure. Because the flexible conductor undergoes elastic deformation when it contacts the first side surface of the flexible circuit board under pressure, it absorbs the impact through deformation when the pen tip is dropped or impacted, thus preventing damage to the sensor.

Description

Technical Field

[0001] This disclosure relates to the field of electronic equipment technology, and more particularly to a sensor and an electromagnetic pen. Background Technology

[0002] In related technologies, to meet user needs, electromagnetic pens are equipped with sensors to obtain the pressure from the pen tip and thus the pressure applied during use. One end of the pen tip is connected to the sensor. However, common integrated variable capacitor and variable resistor sensors have weak shock resistance. When the pen tip is dropped or impacted, a large impact force will be generated on the sensor, causing damage. In addition, their manufacturing cost is high and the process is complex. Utility Model Content

[0003] To overcome the problems existing in related technologies, this disclosure provides a sensor and an electromagnetic pen.

[0004] According to some embodiments of this disclosure, a sensor is provided, comprising: a flexible circuit board; a variable capacitor disposed on the flexible circuit board, the variable capacitor including a first electrode and a second electrode, the flexible circuit board having a first side surface, the first electrode and the second electrode being located on the first side surface, and a capacitance being present between the first electrode and the second electrode; and a flexible conductor disposed toward the first side surface, the flexible conductor contacting the first side surface under the action of a measured pressure and changing the contact area with the first side surface, the contact area being mapped to the capacitance value of the variable capacitor, the capacitance value being used to characterize the pressure value of the measured pressure.

[0005] In some embodiments, the flexible circuit board includes a first pin and a second pin, the first pin being electrically connected to the first electrode and the second pin being electrically connected to the second electrode, the first pin and the second pin being used to output the capacitance value.

[0006] In some embodiments, the flexible circuit board further includes a first trace and a second trace; at least a portion of the first trace is exposed on the first side for contact with the flexible conductor, and the first trace forms the first electrode; at least a portion of the second trace is exposed on the first side for contact with the flexible conductor, and the second trace forms the second electrode.

[0007] In some embodiments, there are multiple first traces and multiple second traces; the multiple first traces and multiple second traces are arranged in an alternating pattern.

[0008] In some embodiments, the first trace forms at least three first electrodes, the second trace forms at least three second electrodes, the at least three first electrodes and the at least three second electrodes are arranged alternately at equal intervals, and the capacitance between adjacent first electrodes and second electrodes varies with the change of the contact area.

[0009] In some embodiments, the flexible circuit board further includes a reinforcing plate; the reinforcing plate is opposite to the first side and is disposed corresponding to the first electrode and the second electrode.

[0010] In some embodiments, the flexible conductor includes a second side surface for contacting the first side surface; the flexible conductor contacts and deforms with the first side surface under the action of the measured pressure, and the contact area between the second side surface and the first side surface increases as the measured pressure increases.

[0011] In some embodiments, the second side surface is a convex arc surface.

[0012] In some embodiments, the second side has a preset roughness.

[0013] According to some embodiments of this disclosure, an electromagnetic pen is provided, comprising: a pen tube; a sensor as described in any of the above embodiments, the sensor being located inside the cavity of the pen tube; and a pen tip disposed at one end of the pen tube, the pen tip being connected to the sensor and used to apply a measured pressure to the sensor.

[0014] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: A gap exists between the first electrode and the second electrode of the variable capacitor, preventing direct connection and thus creating capacitance between them. A flexible conductor contacts a first side of the flexible circuit board under the applied pressure, allowing the flexible conductor in contact with the first side to act as a dielectric between the first and second electrodes, thereby changing the capacitance value between them. As the applied pressure increases or decreases, the contact area between the flexible conductor and the first side changes, i.e., the amount of dielectric between the first and second electrodes changes, thereby changing the capacitance value of the variable capacitor so that this capacitance value can characterize the pressure value being measured. Furthermore, since the flexible conductor undergoes elastic deformation when in contact with the first side of the flexible circuit board under pressure, it absorbs the impact through deformation when the pen tip is dropped or impacted, preventing damage to the sensor.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0017] Figure 1 This is a schematic diagram of the structure of a sensor according to an exemplary embodiment.

[0018] Figure 2 This is a front view of a flexible circuit board according to an exemplary embodiment.

[0019] Figure 3 This is a rear view of a flexible circuit board according to an exemplary embodiment.

[0020] Figure 4 This is a schematic diagram of the structure of a flexible conductor according to an exemplary embodiment.

[0021] Figure 5 This is a schematic diagram of the structure of an electromagnetic pen according to an exemplary embodiment. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0023] In related technologies, to meet user needs, electromagnetic pens are equipped with sensors, such as integrated variable resistance or variable capacitance sensors. One end of the pen tip is used for writing or touch on the screen or digitizer of electronic devices, while the other end connects to the sensor. The sensor obtains the pressure applied by the pen tip, thus acquiring the pressure exerted by the user during use. However, common integrated variable capacitance and variable resistance sensors have weak shock resistance. When the pen tip is dropped or impacted, a large impact force is generated on the sensor, causing damage. Furthermore, their manufacturing cost is high and the process is complex.

[0024] To address the aforementioned technical problems, this disclosure provides a sensor and an electromagnetic pen. Pressure values ​​are detected using a variable capacitor and a flexible conductor. Furthermore, in the event of a drop or impact to the pen tip, the flexible conductor absorbs the impact through deformation, preventing damage to the sensor.

[0025] Figure 1 This is a schematic diagram of the structure of a sensor according to an exemplary embodiment. Figure 2 This is a front view of a flexible circuit board 1 according to an exemplary embodiment. Figure 4This is a schematic diagram illustrating the structure of a flexible conductor 2 according to an exemplary embodiment. Figure 1 , Figure 2 and Figure 4 As shown, the sensor includes a flexible circuit board 1, a variable capacitor 18, and a flexible conductor 2. The flexible circuit board 1 is bendable; by bending the flexible circuit board 1, its first side 16 can face the flexible conductor 2, facilitating contact between the first side 16 and the flexible conductor 2. The variable capacitor 18 can be disposed on the flexible circuit board 1. The variable capacitor 18 may include a first electrode 11 and a second electrode 12. The flexible circuit board 1 has a first side 16, and the first electrode 11 and the second electrode 12 are located on the first side 16, with a capacitance between the first electrode 11 and the second electrode 12. The flexible conductor 2 is disposed facing the first side 16. Under the action of the measured pressure, the flexible conductor 2 contacts the first side 16, changing the contact area with the first side 16. The contact area is mapped to the capacitance value of the variable capacitor 18, which characterizes the pressure value of the measured pressure.

[0026] The first electrode 11 and the second electrode 12 of the variable capacitor 18 are spaced apart and not directly connected, so that there is capacitance between the first electrode 11 and the second electrode 12. The flexible conductor 2 contacts the first side surface 16 of the flexible circuit board 1 under the measured pressure, so that the flexible conductor 2 in contact with the first side surface 16 can act as a dielectric between the first electrode 11 and the second electrode 12, thereby changing the capacitance value between the first electrode 11 and the second electrode 12. As the measured pressure increases or decreases, the contact area between the flexible conductor 2 and the first side surface 16 changes, that is, the amount of dielectric between the first electrode 11 and the second electrode 12 changes, thereby changing the capacitance value of the variable capacitor 18 so that the capacitance value can characterize the pressure value of the measured pressure. On the other hand, since the flexible conductor 2 undergoes elastic deformation when it contacts the first side surface 16 of the flexible circuit board 1 under pressure, when the pen tip 6 is dropped or impacted, the flexible conductor 2 absorbs the impact through deformation, which can prevent damage to the sensor.

[0027] In some embodiments, the flexible circuit board 1 includes a first pin 13 and a second pin 14. The first pin 13 is electrically connected to a first electrode 11, and the second pin 14 is electrically connected to a second electrode 12. The first pin 13 and the second pin 14 are used to output a capacitance value. For example, the flexible circuit board 1 is connected to the mainboard of the electromagnetic pen via the first pin 13 and the second pin 14, so that the flexible circuit board 1 is electrically connected to a control chip located on the mainboard. The control chip obtains the pressure value of the measured pressure by acquiring the capacitance value of the variable capacitor 18.

[0028] In some embodiments, the flexible circuit board 1 further includes a first trace and a second trace. At least a portion of the first trace is exposed on a first side 16 for contact with the flexible conductor 2, and the first trace forms a first electrode 11. At least a portion of the second trace is exposed on the first side 16 for contact with the flexible conductor 2, and the second trace forms a second electrode 12. In other words, by designing the traces of the flexible circuit board 1, namely the first trace and the second trace, a capacitor can be formed between the first trace and the second trace.

[0029] In some embodiments, the first trace and the second trace are embedded in the first side 16 of the flexible circuit board 1, with one side of the first trace exposed on the first side 16 and one side of the second trace exposed on the first side 16 for contacting the flexible conductor 2. The portion of the flexible circuit board 1 between the first trace and the second trace serves as a dielectric.

[0030] In other embodiments, the first trace and the second trace are disposed on the first side 16 of the flexible circuit board 1, and there is a gap between the first trace and the second trace, with air in the gap serving as a dielectric. When the flexible conductor 2 comes into contact with the first side 16 under the action of the measured pressure, part of the flexible conductor 2 is embedded in the gap between the first trace and the second trace as a dielectric, thereby changing the capacitance value.

[0031] In some embodiments, there are multiple first traces and multiple second traces. The multiple first traces and multiple second traces are arranged alternately. By setting the multiple first traces and second traces in an alternate arrangement, the capacitance value of the variable capacitor 18 is increased.

[0032] In some embodiments, the first trace can form at least three first electrodes 11, and the second trace can form at least three second electrodes 12. The at least three first electrodes 11 and at least three second electrodes 12 are arranged alternately and at equal intervals. The capacitance value between adjacent first electrodes 11 and second electrodes 12 can vary with the change in the contact area between the flexible conductor 2 and the first side surface 16. By alternating the arrangement of multiple first electrodes 11 and multiple second electrodes 12, adjacent electrodes can form capacitor structures, thereby increasing the capacitance value variation of the variable capacitor 18. Furthermore, by alternating the arrangement of multiple first electrodes 11 and multiple second electrodes 12 at equal intervals, the electric field of the capacitor can be made uniform and symmetrical, improving the consistency of capacitor performance formed by different first electrodes 11 and second electrodes 12. At least three first electrodes 11 are connected in parallel, and the first pin 13 is connected in series with the at least three first electrodes 11 connected in parallel. At least three second electrodes 12 are connected in parallel, and the second pin 14 is connected in series with the at least three second electrodes 12 connected in parallel. The first pin 13 and the second pin 14 send the capacitance change between the first electrodes 11 and the second electrodes 12 to the main board of the electromagnetic pen in real time. This capacitance change is the real-time capacitance value of the variable capacitor 18, which is used to characterize the pressure applied to the tip of the electromagnetic pen.

[0033] Figure 2 This is a front view of a flexible circuit board 1 according to an exemplary embodiment. Figure 3 This is a rear view of a flexible circuit board 1 according to an exemplary embodiment. For example, as shown... Figure 2 and Figure 3 As shown, multiple first traces located on the first side 16 of the flexible circuit board 1 are arranged in a grid pattern. Connecting traces 15 located on the back side of the first side 16 connect the multiple first traces, and the multiple first traces are electrically connected to the first pin 13 to form a first electrode 11. Multiple second traces located on the first side 16 of the flexible circuit board 1 are arranged in a grid pattern, and the multiple second traces are electrically connected to the second pin 14 to form a second electrode 12. The multiple second traces are arranged in an interdigitated pattern. The first traces, second traces, and connecting traces 15 are formed using a circuit deposition process.

[0034] It should be noted that this disclosure does not specifically limit the number of the first and second traces. Those skilled in the art can configure the first and second traces according to the actual situation, so that there is a capacitor between the first and second traces.

[0035] In some embodiments, the flexible circuit board 1 further includes a reinforcing plate 17. The reinforcing plate 17 is disposed away from the first side 16 and corresponds to the first electrode 11 and the second electrode 12. By providing the reinforcing plate 17, the strength of the flexible circuit board 1 at the first side 16 is improved, and deformation of the flexible circuit board 1 due to long-term compression by the flexible conductor 2 is avoided.

[0036] like Figure 4 As shown, in some embodiments, the flexible conductor 2 includes a second side surface 21 for contacting the first side surface 16. Under the action of the measured pressure, the flexible conductor 2 contacts and deforms with the first side surface 16. As the measured pressure increases, the contact area between the second side surface 21 and the first side surface 16 increases. Due to the increased contact area, more of the flexible conductor 2 acts as the dielectric between the first electrode 11 and the second electrode 12, thereby changing the capacitance value between the first electrode 11 and the second electrode 12.

[0037] In some embodiments, the flexible conductor 2 further includes a connecting portion 22 for connecting to a force-bearing structure, i.e., transmitting the measured pressure. The connecting portion 22 is opposite to the second side surface 21. For example, the connecting portion 22 has a tubular or columnar structure and is connected to one end of the columnar tip 6 of the electromagnetic pen.

[0038] In some embodiments, the second side 21 is a convex arc surface to increase the change in the contact area between the second side 21 and the first side 16 under the action of the measured pressure.

[0039] For example, the second side surface 21 can be a partial spherical surface or a partial cylindrical side surface.

[0040] In some embodiments, the second side 21 has a preset roughness to prevent the second side 21 of the flexible conductor 2 from sticking to the flexible circuit board 1 and affecting the detection accuracy of the sensor.

[0041] When the flexible conductor 2 is not under pressure, air fills the space between the first electrode 11 and the second electrode 12. Under the pressure being measured, the second side 21 of the flexible conductor 2 contacts the first side 16, and conductive adhesive fills the space between the first electrode 11 and the second electrode 12. Furthermore, as the measured pressure increases, the air between the first electrode 11 and the second electrode 12 gradually decreases, the contact area between the flexible conductor 2 and the flexible circuit board 1 gradually increases, and the capacitance value of the variable capacitor gradually increases.

[0042] Figure 5 This is a schematic diagram illustrating the structure of an electromagnetic pen according to an exemplary embodiment. For example... Figure 5 As shown, according to some embodiments of this disclosure, an electromagnetic pen is provided, including: a pen tube 5; a sensor as described in any of the above embodiments, the sensor being located inside the cavity of the pen tube 5; and a pen tip 6, disposed at one end of the pen tube 5, the pen tip 6 being connected to the sensor, and used to apply a measured pressure to the sensor.

[0043] Figure 5 As shown, the main body of the pen tip 6 has a columnar structure. One end of the pen tip 6 protrudes from the pen tube 5, and the other end of the pen tip 6 is connected to the flexible conductor 2 so that the pressure to be measured is transmitted to the sensor through the pen tip 6.

[0044] In some embodiments, the electromagnetic pen further includes a magnetic core coil 7 and a piston 4. The magnetic core coil 7 is located inside the pen tube 5 and is sleeved on the pen tip 6 for transmitting and / or receiving signals. The piston 4 is slidably disposed inside the pen tube 5, with one side of the piston 4 connected to the pen tip 6 and the other end of the piston 4 connected to the flexible conductor 2. The piston 4 is used to control the direction in which the measured pressure is applied to the sensor. The sliding direction of the piston 4 is parallel to the axis of the pen tip 6.

[0045] In some embodiments, the electromagnetic pen further includes a mainboard 3, and a flexible circuit board 1 is soldered to the mainboard of the electromagnetic pen via a first pin 13 and a second pin 14, so that the flexible circuit board 1 is electrically connected to a control chip located on the mainboard 3. The control chip obtains the pressure value of the measured pressure by acquiring the capacitance value of the variable capacitor.

[0046] In the above detailed description, reference has been made to the accompanying drawings, which illustrate specific aspects of this disclosure by way of illustration. In this regard, terms indicating direction or positional relationship, such as “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential,” are used with reference to the orientation of the described figures. Since components of the described device can be positioned in multiple different orientations, directional terms are used for illustrative purposes and not for limitation. It should be understood that other aspects can be utilized and structural or logical changes can be made without departing from the concept of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0047] It should be understood that, unless otherwise specifically indicated, features of various embodiments of this disclosure described herein can be combined with each other. As used herein, the term "and / or" includes any of the associated listed items and any combination of any two or more; it should be understood that, unless otherwise expressly specified and limited, the terms "joining," "attaching," "mounting," "connecting," "linking," "fixing," etc., used in the embodiments of this disclosure should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral part; as a mechanical connection, an electrical connection, or a communicative connection; as a direct connection or an indirect connection through an intermediate medium; as a connection within two elements or an interaction between two elements, unless otherwise expressly limited. Those skilled in the art will understand the specific meaning of the above terms herein according to the specific circumstances.

[0048] Furthermore, the term "above" as used herein with respect to components, elements, or material layers formed or located "above" a surface may be used to indicate that the component, element, or material layer is "indirectly" positioned (e.g., placed, formed, deposited, etc.) on the surface such that one or more additional components, elements, or layers are arranged between the surface and the component, element, or material layer. However, the term "above" as used with respect to components, elements, or material layers formed or located "above" a surface may also optionally have a specific meaning: that the component, element, or material layer is "directly" positioned (e.g., placed, formed, deposited, etc.) on the surface, for example, in direct contact with the surface.

[0049] It should be understood that spatial relative terms, such as “above,” “upper,” “below,” and “lower,” are used herein to describe the relationship between one element and another shown in the figures. In addition to the orientation depicted in the figures, these spatial relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “above” or “upper” relative to another element would be “below” or “lower” relative to that other element. Thus, depending on the spatial orientation of the device, the term “above” encompasses both above and below orientations. Devices may have other orientations (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0050] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited to these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, a first component, part, region, layer, or section mentioned in the examples may also be referred to as a second component, part, region, layer, or section. Furthermore, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first” or “second” may explicitly or implicitly include at least one of that feature.

[0051] It is further understood that the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another, and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this disclosure, first information can also be referred to as second information, and similarly, second information can also be referred to as first information.

[0052] In this description, "multiple" means at least two, referring to two or more, such as two, three, etc., unless otherwise explicitly specified. Other quantifiers are similar. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, unless otherwise specified or clearly indicated from the context, the articles "a" and "an" as used in this application and the appended claims are generally understood to mean "one or more."

[0053] It should be understood that, unless otherwise specifically indicated, features of various embodiments of this disclosure described herein can be combined with each other. As used herein, the term "and / or" includes any one of the related listed items and any combination of two or more; "and / or" describes the association relationship between related objects, indicating that three relationships may exist, for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. Similarly, "at least one of..." includes any one of the related listed items and any combination of two or more.

[0054] Furthermore, the term "exemplary" is used herein to indicate that it serves as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as advantageous compared to other aspects or designs. Rather, the use of the term "exemplary" is intended to present concepts in a concrete manner. As used herein, the term "or" is intended to indicate an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from the context, "X applies A or B" is intended to indicate any of the natural inclusive permutations. That is, if X applies A; X applies B; or X applies both A and B, then applying A or B satisfies the condition under any of the foregoing instances.

[0055] Similarly, although this disclosure has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art upon reading and understanding the specification and drawings. This disclosure includes all such modifications and variations and is limited only by the scope of the claims. In particular, with respect to the various functions performed by the components described above (e.g., elements, resources, etc.), unless otherwise indicated, the terminology used to describe such components is intended to correspond to any component (functionally equivalent) that performs the specific function of the described component, even if it is not structurally equivalent to the disclosed structure. Furthermore, although specific features of this disclosure may have been disclosed with respect to only one of several implementations, such features may be combined with one or more other features of other implementations, as may be desired and advantageous to any given or particular application. Moreover, with regard to the terms “comprising,” “owning,” “having,” “having,” or variations thereof as used in this disclosure, such terms are intended to be inclusive in a manner similar to the term “including.”

[0056] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

[0057] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A sensor, characterized by include: Flexible circuit board (1); A variable capacitor (18) is arranged on the flexible circuit board (1). The variable capacitor (18) includes a first electrode (11) and a second electrode (12). The flexible circuit board (1) has a first side (16). The first electrode (11) and the second electrode (12) are located on the first side (16). There is a capacitance between the first electrode (11) and the second electrode (12). A flexible conductor (2) is disposed facing the first side (16). The flexible conductor (2) contacts the first side (16) under the action of the measured pressure and changes the contact area between the flexible conductor (2) and the first side (16). The contact area is mapped to the capacitance value of the variable capacitor (18). The capacitance value is used to characterize the pressure value of the measured pressure.

2. The sensor of claim 1, wherein, The flexible circuit board (1) includes a first pin (13) and a second pin (14). The first pin (13) is electrically connected to the first electrode (11), and the second pin (14) is electrically connected to the second electrode (12). The first pin (13) and the second pin (14) are used to output the capacitance value.

3. The sensor of claim 2, wherein, The flexible circuit board (1) also includes a first trace and a second trace; At least a portion of the first trace is exposed on the first side (16) for contact with the flexible conductor (2), and the first trace forms the first electrode (11); At least a portion of the second trace is exposed on the first side (16) for contact with the flexible conductor (2), and the second trace forms the second electrode (12).

4. The sensor of claim 3, wherein, Both the first and second traces are multiple; Multiple first traces and multiple second traces are arranged in an alternating pattern.

5. The sensor of claim 4, wherein, The first trace forms at least three first electrodes (11), and the second trace forms at least three second electrodes (12). The at least three first electrodes (11) and the at least three second electrodes (12) are arranged at equal intervals and are staggered. The capacitance between adjacent first electrodes (11) and second electrodes (12) changes with the change of the contact area.

6. The sensor of claim 5, wherein, The flexible circuit board (1) also includes a reinforcing plate (17); The reinforcing plate (17) is away from the first side (16) and is disposed corresponding to the first electrode (11) and the second electrode (12).

7. The sensor of claim 1, wherein, The flexible conductor (2) includes a second side surface (21) for contacting the first side surface (16); The flexible conductor (2) comes into contact with the first side surface (16) and deforms under the action of the measured pressure. As the measured pressure increases, the contact area between the second side surface (21) and the first side surface (16) increases.

8. The sensor of claim 7, wherein, The second side (21) is a convex arc surface.

9. The sensor of claim 8, wherein, The second side (21) has a preset roughness.

10. An electromagnetic pen, characterized by include: Pen tube (5); The sensor according to any one of claims 1 to 9, wherein the sensor is located inside the cavity of the pen tube (5); A pen tip (6) is arranged at one end of the pen tube (5), and the pen tip (6) is connected with the sensor, and is used for applying the measured pressure to the sensor.

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