KR20140048655A - Electronic pen detecting writing pressure - Google Patents

Abstract

According to the present invention, an electronic pen having an improved pen pressure detection function stores energy by resonating with electromagnetic force (external electromagnetic force) emitted from a tablet and emits electromagnetic force (applied electromagnet force) on its own using the stored energy so that the tablet is able to detect the emission location of the applied electromagnet force within the pen detection area of the tablet. The electronic pen includes: a resonating circuit which includes at least an inductor (L) and a capacitor (C); a pen tip; a conductive rubber member which is elastically shrinkable; a PCB which has a contact part of which the contact area increases as the conductive rubber member is touched and shrunk when the conductive rubber member is pressed to the back by the pen tip; at least two contact electrodes which are exposed to the contact part of the PCB and switched by being in contact with the conductive rubber member; and at least one pen pressure detecting capacitor (ΔC) which is connected to or separated from the resonating circuit by switching of the contact electrodes.

Description

ELECTRONIC PEN DETECTING WRITING PRESSURE

The present invention relates to an electronic pen having a pen pressure sensing function, and more particularly, to an electronic pen configured to detect a pen pressure in contact with a tablet.

Recently, a device for inputting a user's operation by direct writing on a predetermined plane (for example, a pen sensing area of a tablet) using a pen-type tool (for example, an electronic pen) has been widely used. have.

In addition, electronic pens capable of operating wirelessly without a built-in battery or the like have been developed so that the portable pen and the like used by the user can be reduced in portability and weight and can be utilized freely with respect to the tablet.

1 is a view for explaining the operation principle of a conventional tablet and an electronic pen operating in an electromagnetic induction manner. In Fig. 1 (a), as a part of the tablet, the coil drive driver 20 and the loop coil 30 can be seen, and as an example of the electronic pen 100, a writing instrument incorporating a resonant circuit composed of a capacitor and an inductor Can be seen.

When the coil drive driver 20 receives a switching pattern having a predetermined frequency (that is, the resonant frequency of the resonant circuit of the electronic pen) under the control of the tablet MCU or the like, the coil driving driver 20 receives an AC voltage corresponding to the frequency of the input switching pattern. Output to the loop coil 30.

The loop coil 30 has a predetermined inductance and emits an induced electromagnetic force (external electromagnetic force 1) by an input AC voltage.

On the other hand, in the resonance circuit of the electronic pen 100, resonance is caused by the externally applied electromagnetic force to generate an induced current, and the generated induced current is stored in the inductor and the capacitor. When the emission of the external electromagnetic force is stopped, the resonance circuit resonates by self-stored energy (induced current) to emit an induced electromagnetic force (acting electromagnetic force 2).

On the other hand, in the tablet, the inner space of the loop coil 30 constitutes the pen sensing area A. In the pen sensing area A, although not shown, various types of electromagnetic force sensing means can be arranged. As the electromagnetic force sensing means, for example, a line antenna structure which can refer to the patent document 10-984036 can be used.

On the other hand, when the electromagnetic pen 100 itself emits an electromagnetic force (acting electromagnetic force), the pen sensing area A of the tablet senses the electromagnetic force acting on the electronic pen, Sensing position) is measured, and it is regarded that the user intends to input an operation using the electronic pen 100 to the measured coordinates.

1 (b) is a view showing a waveform of an external electromagnetic force emitted from the loop coil. When the AC drive voltage is output from the coil drive driver 20 to the loop coil 30 according to the switching pattern, an external electromagnetic force gradually rising due to the inductance existing in the loop coil 30 is emitted. The external electromagnetic force is released at the same specific intensity after a lapse of a predetermined time. If the switching pattern is interrupted by the control of the MCU at a predetermined time (for example, at time B) and the AC voltage is interrupted, It stops.

Fig. 1 (c) is a view showing the waveform of the working electromagnetic force output from the resonance circuit of the electronic pen. The resonant circuit may temporarily store energy by the induced current generated by the external electromagnetic force. When the emission of the external electromagnetic force is stopped, the resonant circuit may resonate by the stored energy to release the working electromagnetic force. The working electromagnetic force is reduced by the consumption of stored energy.

의 식에 의해 결정된다. At this time, the working electromagnetic force has a frequency of f0. f0 may be determined by capacitance and inductance included in the resonant circuit of the electronic pen 100. In other words,

. ≪ / RTI >

On the other hand, since the frequency of the external electromagnetic force and the resonance frequency of the resonance circuit coincide with each other or a multiple thereof causes the most efficient resonance, the frequency of the AC voltage output from the coil drive driver 20 (that is, the frequency of the switching pattern output from the MCU ) Is also preferably f0.

Next, with reference to FIG. 2, it is a figure explaining the method of changing the resonance frequency of a resonance circuit. The resonant circuit may be formed by forming at least one inductor L and at least one capacitor C in a loop. In the resonant circuit, a plurality of inductors and a plurality of capacitors may be configured in series or in parallel. Hereinafter, one equivalent device will be described and described.

로 표시할 수 있다. 또한, 작용 전자기력의 주기(T0)는

로 나타낼 수 있다.2 (a) shows a resonant circuit formed by connecting one inductor having an inductance L and one capacitor having a capacitance C. In Fig. The resonant frequency (f0) of the working electromagnetic force emitted from this basic resonant circuit is

As shown in FIG. In addition, the period T0 of the applied electromagnetic force is

.

로 산출할 수 있다. FIG. 2 (b) shows a circuit in which a contact sensing capacitor ΔC having a variable capacitance is added to the basic resonant circuit of FIG. 2 (a).

.

로 된다.FIG. 2 (c) shows a circuit in which a contact sensing inductor ΔL having an inductance variable is added to the resonance circuit of FIG. 2 (a).

.

로 공진 주파수를 결정할 수 있다. In FIG. 2 (d), a contact sensing capacitor and a contact sensing inductor are added at the same time. In this case,

The resonance frequency can be determined.

Therefore, the electronic pen 100 mechanically connects the pen tip, which is in contact with the pen sensing area A of the tablet, the contact sensing inductor and / or the contact sensing capacitor, to the pressure at which the user presses the electronic pen against the tablet. Accordingly, if the inductance and / or capacitance are configured to change, and the amount of change in inductance and / or capacitance in the tablet can be measured, the user can measure the pen pressure indicating the degree of pressing the electronic pen 100 against the tablet.

Fig. 3 is a diagram showing how the resonance frequency of the working electromagnetic force emitted from the electronic pen changes due to a change in inductance and / or capacitance included in the resonance circuit of the electronic pen. Referring to the drawing, when the pen pressure does not act on the electronic pen, an operating electromagnetic force having a basic resonance frequency f0 is output. However, the pen pressure acts to change the inductance and / or capacitance of the resonant circuit. I can see that there is.

The change in inductance and / or capacitance is not only caused by the pressure,

The tablet detects the period (T) of the output electromagnetic force and compares the detected period (T) with the basic period (T0) to calculate the amount of change in inductance and / or capacitance to measure the pen pressure.

Fig. 4 is a view showing an example of the configuration of the electronic pen.

4 (a) shows an example in which a pressure sensor whose capacitance changes according to the pressure acting on the electronic pen is applied. The illustrated coil 110 is for forming an inductor resonated by an external electromagnetic force and is formed around a ferrite core 112 in the form of a tube. A pen tip 105 protruding forward of the electronic pen is inserted and inserted into the ferrite core 112 and a pressure sensor 114 is disposed behind the pen tip 105. Thereby, when the user presses the electronic pen against the tablet, the pen tip 105 is pressed backward, and the pen tip 105 presses the pressure sensor 114 so that the pressure can be sensed. The pen tip 105 and the ferrite core 112 may move integrally within the ferrite core 112. However, the pen tip 105 and the ferrite core 112 may operate integrally.

4 (b) is a diagram showing an example in which a pressure acting on the electronic pen is sensed by a change in inductance. The coil 110 is formed around the bobbin 113, A movable ferrite core 112 is disposed in accordance with the depression of the pen tip 105. [ In this configuration, since the inductance changes according to the movement of the ferrite core 112, the pressure is sensed by using the inductance.

However, the conventional electronic pen as described above has the disadvantage of using an expensive pressure sensor, and there is a problem that the measurement of changing capacitance or inductance must be precise.

The present invention is to solve the above problems, it is possible to define a change in capacitance and / or inductance in a multi-stage by a simple circuit configuration, an electronic pen to accurately measure the capacitance and / or inductance according to each step To provide.

In addition, the present invention is to provide a method for producing such an electronic pen in a simple method.

The electronic pen having a pen pressure sensing function according to the present invention for achieving the above object, resonates with the electromagnetic force (external electromagnetic force) emitted from the tablet, and stores energy, and emits an electromagnetic force (acting electromagnetic force) by itself by the stored energy. A resonant circuit configured to allow the tablet to sense the emission position of the working electromagnetic force within the pen sensing region, the resonant circuit having at least an inductor (L) and a capacitor (C); A pen tip positioned in front of the electronic pen and movable behind the electronic pen by a pen pressure acting upon contact with the pen sensing area of the tablet; A conductive rubber coupled to the pen tip and configured to be elastically crushed; A PCB having a contact portion configured to contact with the rubber and increase a contact area according to the degree of crushing when the conductive rubber is in contact with the rubber when the conductive rubber is pressed backward by a pen pressure acting on the pen tip; At least two contact electrodes exposed to the contacts of the PCB and switched by the contact of the conductive rubber; At least one pressure sensing capacitor ΔC connected to or separated from the resonant circuit by switching of the contact electrode.

In addition, the conductive rubber is a round shape protruding toward the contact portion of the PCB, the contact portion of the PCB is formed in a vertical flat shape or curved shape in the direction toward the conductive rubber.

In addition, the contact portion is formed by forming a pattern of the contact electrode on the surface of the flexible substrate, bending the flexible substrate by folding the pattern outward, and then placing the bent outer surface toward the conductive rubber.

The pressure sensing capacitor may include at least one pressure sensing inductor connected to or separated from the resonant circuit by switching of the contact electrode in place of or in addition to the pressure sensing capacitor.

In addition, the electronic pen having a pen pressure sensing function of another form for achieving the above-mentioned object, resonates to the electromagnetic force (external electromagnetic force) emitted from the tablet, and stores the energy, by itself stored electromagnetic force (acting electromagnetic force) A resonant circuit configured to emit a light emitting device so that the tablet can sense a discharge position of the working electromagnetic force in the pen sensing region, the resonant circuit having at least an inductor (L) and a capacitor (C); A pen tip positioned in front of the electronic pen and movable behind the electronic pen by a pen pressure acting upon contact with the pen sensing area of the tablet; A conductive rubber coupled to the pen tip and configured to be elastically crushed; A PCB having a contact portion configured to contact with the rubber and increase a contact area according to the degree of crushing when the conductive rubber is in contact with the rubber when the conductive rubber is pressed by a pen pressure acting on the pen tip; The conductive pattern is exposed to the contact portion of the PCB in a vortex shape having a plurality of turns, has a predetermined inductance and forms a part of the resonant circuit, and the conductive area is changed as the contact area of the conductive rubber changes. The number of turns in contact with the rubber is changed to include a pressure-sensitive inductor (ΔL) for changing the inductance.

In addition, the contact portion is formed by forming a pattern of the pressure sensing inductance on the surface of the flexible substrate, bending the flexible substrate by folding the pattern outward, and then placing the bent outer surface toward the conductive rubber. .

According to the present invention having the above-described configuration, the change in capacitance and / or inductance can be defined in multiple steps by the electronic pen formed by a simple circuit configuration, and the capacitance and / or inductance according to each step can be accurately measured. Will be. As a result, the pen pressure of the electronic pen can be detected accurately and accurately.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the operating principle of the conventional tablet and electronic pen which operate by an electromagnetic induction system.
2 is a view for explaining a method of changing the resonance frequency of the resonance circuit included in the electronic pen.
FIG. 3 is a diagram illustrating a change in resonant frequency of a working electromagnetic force emitted from the electronic pen by changing inductance and / or capacitance included in the resonant circuit of the electronic pen.
4 is a diagram showing a schematic configuration example of an electronic pen.
5 is a view for explaining the principle and configuration of an electronic pen having a pen pressure sensing function according to a first embodiment of the present invention.
FIG. 6 is a diagram illustrating a shape of a contact part formed with the common electrode and the contact electrode exposed.
7 is a view showing another example of configuring a contact unit in the electronic pen according to the first embodiment of the present invention.
8 is a view for explaining the principle and configuration of an electronic pen having a pen pressure sensing function according to a second embodiment of the present invention.
FIG. 9 is a view schematically illustrating the pen pressure sensing inductor structure shown in FIG. 8.
FIG. 10 is a diagram illustrating another example of configuring a contact PCB in the electronic pen according to the second embodiment.

Hereinafter, various configurations and operations of an electronic pen having a pen pressure sensing function according to the present invention will be described with reference to FIGS. 5 to 10.

5 to 7 illustrate an electronic pen having a pen pressure sensing function according to a first embodiment of the present invention, and describes an electronic pen that senses a pen pressure using a pen pressure sensing capacitor.

5 is a view for explaining the principle and construction of an electronic pen having a function of detecting a pressure according to a first embodiment of the present invention. FIG. 5 (a) is a view for explaining the principle of pen pressure sensing in an electronic pen. In FIG. A circuit for adding contact sensing capacitors DELTA C1, DELTA C2, DELTA C3, DELTA C4 through a switch is shown. According to such a circuit configuration, it is possible to predict that the capacitance of the entire resonance circuit will change according to the operation of each switch. In addition, if the operation of each switch can be controlled according to the pen pressure, it can be predicted that the pen pressure can be measured step by step according to the addition of contact sensing capacitors.

FIG. 5 (b) shows only an important part of the form in which the circuit as shown in FIG. 5 (a) is implemented in the electronic pen.

The pen tip 105 is disposed to face the front of the electronic pen, and the pen tip 105 is connected to a ferrite core 112 having an inductor. On the other hand, the rear of the ferrite core 112 is provided with a conductive rubber 120 of the double-type form.

Meanwhile, in the vicinity of the conductive rubber 120, one or more contact sensing capacitors ΔC and the PCB 140 on which the capacitors C are formed are in contact with or in close proximity to each other.

At this time, the pen tip 105, the ferrite core 112 and the conductive rubber 120 is integrally configured to move back and forth within the body (not shown) of the electronic pen, the PCB 140 is the body of the electronic pen (shown) Not fixed). The surface facing the conductive rubber 120 in the PCB 140 constitutes a contact portion 142 in contact with the conductive rubber 120.

In addition, the conductive parts (contact electrodes) 151 and 152 extending from the plurality of contact sensing capacitors are exposed to the conductive rubber 120 in the contact part 142.

When the user contacts the tablet with the electronic pen including such a configuration, the pressure by the pen pressure applied to the pen tip 105 acts on the ferrite core 112 so that the conductive rubber 120 contacts the PCB 140, When the pen pressure is made stronger by contacting the electronic pen more strongly, the conductive rubber 120 is pressed by the contact portion 142 of the PCB 140 and is crushed, and as the crushed, the conductive rubber 120 and the PCB 140 The contact area with the contact portion 142 is widened.

At this time, if the contact electrodes 152 of the contact sensing capacitors ΔC are sequentially arranged to be connected to the conductive rubber according to the area of the contact surface, the contact sensing capacitors are sequentially formed according to the pen pressure applied to the conductive rubber 120. It can be connected to the resonant circuit.

5 (c) is a view for explaining the action of the contact portion and the conductive rubber of the PCB. The contact portion 142 of the PCB 140 includes one common electrode (which may be referred to as a contact electrode as needed) and contact electrodes 152 extending from each of the contact sensing capacitors ΔC1, ΔC2, ΔC3, and ΔC4. It is sequentially spaced apart from the common electrode. The conductive rubber 120 shown in dashed lines is a state in which the pen pressure does not act on the electronic pen, and is shown as being slightly in contact with the common electrode. Of course, in this state, the conductive rubber 120 may be kept in a spaced state so as not to contact any of the common electrode 151 and the contact electrode 152.

로 변화할 것이며, 이에 의해 타블렛에서는 변화된 공진 주파수로부터 커패시턴스의 변화량을 산출하고, 필압을 인식하게 될 것이다.
The conductive rubber 120 shown by a solid line shows a state in which the pen pressure is applied to the pen tip 105 of the electronic pen, and the conductive rubber 120 is pressed and crushed by the contact portion 142 of the PCB 140. In the illustrated state, it can be seen that the contact surface of the conductive rubber 120 is formed up to the contact electrodes of the two contact sensing capacitors ΔC1 and ΔC2, including the common electrode 151. In this state, the capacitance of the resonance circuit will be C + ΔC1 + ΔC2, and the resonance frequency

So that the tablet will calculate the amount of change in capacitance from the changed resonant frequency and will recognize the pressure.

6 is a view illustrating a shape of a contact part formed with the common electrode and the contact electrode exposed. 6 (a) shows a contact portion 142 having a vertically flat shape in a direction toward the conductive rubber. The contact portion 142 is formed to expose the contact electrode 152 and the common electrode 151.

6 (b) shows that the contact portion may be configured by using a separate PCB. The contact portion 142 may be concave bent in a direction toward the conductive rubber 120. When the conductive rubber 120 is formed in a convex shape (for example, see FIG. 5), and the contact portion 142 is bent in this manner, the contact surface can be easily widened even when a small pen pressure is applied to the conductive rubber 120. have.

Of course, if necessary, the contact surface may be configured to be convex on the contrary.

On the other hand, the contact portion of Fig. 6 (b) is formed by dividing the contact electrode into two (contact electrode '152' and the contact electrode "152"). In this configuration, without the common electrode 151 The circuit may be configured to perform a switching operation by bringing the two contact electrodes into contact with the conductive rubber.

6 (c) shows another configuration of the conductive rubber and the contact portion. The conductive rubber 120 is formed flat and the contact portion 142 of the PCB 140 is convex. On the other hand, the inside of the conductive rubber 120 to form a hollow to weaken the elasticity of the conductive rubber 120, it may be configured so that the conductive rubber 120 can be pressed more and more deformed even at a smaller pen pressure.

7 is a diagram illustrating another example of configuring a contact unit. In FIG. 7A, an example in which a contact portion is formed using the flexible substrate 145 is illustrated. By forming a pattern of a common electrode and a contact electrode on the surface of the flexible substrate 145, bending the flexible substrate 145 with the formed pattern outward, and then folding the outer surface toward the conductive rubber 120. It can form a contact such as. When the contact portion is formed in this way, the contact portion can be formed by a simple manufacturing process, and the production cost is reduced.

Further, as shown in FIG. 7B, by mounting the respective components of the resonant circuit on the flexible substrate, forming a pattern of the common electrode 151 and the contact electrode 152 on a portion of the flexible substrate, and bending the corresponding portion, Since the contact portion may be integrally formed, the fabrication may be completed with one substrate.

Next, an electronic pen having a pen pressure sensing function according to a second embodiment of the present invention will be described with reference to FIGS. 8 to 10. In this embodiment, the pen pressure is sensed using a pen pressure sensing inductor.

8 is a view for explaining the principle and configuration of an electronic pen having a pen pressure sensing function according to a second embodiment of the present invention. In this embodiment, a ferrite core and a conductive rubber structure as shown in Fig. 5 (b) are used, except that the contacts and circuit connections of the PCB are different.

Referring to FIG. 8 (a), the contact portion arranges a contact PCB 146 corresponding to the diameter cross-sectional shape of the electronic pen perpendicular to the direction toward the conductive rubber 120, and is disposed on the surface of the contact PCB 146. The conductive coil pattern 154 is formed in a spiral shape having a plurality of turns in a state of being exposed to the outside to form a pen pressure sensing inductor ΔL.

Figure 8 (b) is a view showing a state in which the conductive rubber pressed to the contact PCB in cross section. Referring to the drawings, when the conductive rubber 120 is pressed by the pen pressure, the contact surface is formed by contacting from the convex portion (for example, the center) of the conductive rubber 120, and the stronger the pressure, the larger the contact surface is conductive A portion of the coil pattern 154 constituting the vortex by the rubber 120 will be electrically connected to each other. As a result, the number of turns of the pen pressure sensing inductor will decrease as the pen pressure is applied, and the total inductance of the resonant circuit will be changed.

The resonant frequency of the electronic pen is changed by the changed total inductance, and the tablet detects this to measure the pen pressure.

FIG. 9 is a diagram illustrating only an important part in a form in which the pen sensing inductor structure shown in FIG. 8 is implemented in an electronic pen.

First, FIG. 9 (a) is similar to FIG. 5 (b), wherein the pen tip is disposed to face the front of the electronic pen, and the pen tip 105 is connected to a ferrite core having an inductor. On the other hand, the rear of the ferrite core 112 is provided with a conductive rubber 120 of the double-type form. In addition, the coil pattern of the contact PCB 146 may be in contact with the conductive rubber 120 (not shown).

In FIG. 9A, a PCB 140 having various circuit elements (for example, a capacitor of a resonant circuit) formed on the back of the electronic pen is disposed, and a ferrite core having a conductive rubber 120 coupled to the pen tip 105 ( It is shown as an example of being disposed behind 112.

In FIG. 9B, the PCB and the ferrite core are coupled to each other, the contact PCB 140 is disposed in front of the ferrite core 112, and the conductive rubber 120 is directly bonded to the pen tip 105. The form is shown. In such a configuration, since the weight of the pen tip 105 becomes light, the user can control the pen pressure with a light force.

FIG. 10 shows another example of configuring a contact PCB in the electronic pen according to the second embodiment. In FIG. 10A, a contact PCB is formed using the flexible substrate 147. The spiral coil pattern 154 that forms a pressure-sensitive inductor on the surface of the long flexible substrate 147 is illustrated. ), The flexible substrate 147 is bent and folded with the formed pattern outward, and then the bent outer surface is disposed toward the conductive rubber 120, thereby forming a contact PCB having a contact portion as shown in the drawing. When the contact portion is formed in this way, the contact portion can be formed by a simple manufacturing process, and the production cost is reduced. Further, since the shape of the conductive rubber can be configured in a rectangular cross section as shown in the figure, it can be made of less material than when formed into a circular cross section.

Claims (6)

(External electromagnetic force) emitted from the tablet, stores energy, and emits an electromagnetic force (acting electromagnetic force) by itself by the stored energy so that the tablet can sense the position of emission of the working electromagnetic force within the pen sensing area Wherein the electronic pen comprises:
A resonant circuit having at least an inductor L and a capacitor C;
A pen tip positioned in front of the electronic pen and movable behind the electronic pen by a pen pressure acting upon contact with the pen sensing area of the tablet;
A conductive rubber coupled to the pen tip and configured to be elastically crushed;
A PCB having a contact portion configured to contact with the rubber and increase a contact area according to the degree of crushing when the conductive rubber is in contact with the rubber when the conductive rubber is pressed backward by a pen pressure acting on the pen tip;
At least two contact electrodes exposed to the contacts of the PCB and switched by the contact of the conductive rubber;
An electronic pen having a pen pressure sensing function including at least one pen pressure sensing capacitor (ΔC) connected to or separated from the resonance circuit by switching of the contact electrode. The method of claim 1,
The conductive rubber has a round shape protruding toward the contact portion of the PCB,
The contact portion of the PCB has a pen pressure sensing function, characterized in that formed in a vertical flat shape or curved in the direction toward the conductive rubber. The method of claim 1,
The contact portion may be formed by forming a pattern of the contact electrode on a surface of the flexible substrate, bending the flexible substrate by folding the pattern outward, and then placing the bent outer surface toward the conductive rubber. Electronic pen with pressure sensitivity. The method of claim 1,
And at least one pressure sensing inductor connected to or separated from the resonant circuit by switching of the contact electrode in place of the pressure sensing capacitor or in addition to the pressure sensing capacitor. Having an electronic pen. (External electromagnetic force) emitted from the tablet, stores energy, and emits an electromagnetic force (acting electromagnetic force) by itself by the stored energy so that the tablet can sense the position of emission of the working electromagnetic force within the pen sensing area Wherein the electronic pen comprises:
A resonant circuit having at least an inductor L and a capacitor C;
A pen tip positioned in front of the electronic pen and movable behind the electronic pen by a pen pressure acting upon contact with the pen sensing area of the tablet;
A conductive rubber coupled to the pen tip and configured to be elastically crushed;
A PCB having a contact portion configured to contact with the rubber and increase a contact area according to the degree of crushing when the conductive rubber is in contact with the rubber when the conductive rubber is pressed by a pen pressure acting on the pen tip;
The conductive pattern is exposed to the contact portion of the PCB in a vortex shape having a plurality of turns, has a predetermined inductance and forms a part of the resonant circuit, and the conductive area is changed as the contact area of the conductive rubber changes. An electronic pen having a pen pressure sensing function including a pen pressure sensing inductor (ΔL) in which the number of turns in contact with rubber is changed to change the inductance. The method of claim 1,
The contact portion is formed by forming a pattern of the pressure sensing inductance on the surface of the flexible substrate, bending the flexible substrate by folding the pattern outward, and then placing the bent outer surface toward the conductive rubber. An electronic pen having a pen pressure sensing function.

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