JP2022033028A - Resonance circuit, electromagnetic pen, and its capacity adjustment method - Google Patents

Abstract

To provide a resonance circuit, an electromagnetic pen, and its capacity adjustment method.SOLUTION: An electromagnetic pen, and a resonance circuit used for its capacity adjustment method include an inductance L and a capacitor C that are connected electrically. The capacitor includes a force sensing capacitor Cv and an adjustment capacitor Cq that are connected in series. The adjustment capacitor includes plural fixed-capacity branches connected in parallel, and one short branch. The respective fixed-capacity branches include one fixed capacity and one connection line (J to J3), and changes a capacity value of the adjustment capacitor and retains matching of the capacity value of the capacitor by turning on or off the connection line selectively or accessing the short branch.SELECTED DRAWING: Figure 2

Description

The present invention relates to the technical field of electromagnetic external input, and particularly to a resonant circuit, an electromagnetic pen and a method for adjusting the capacitance thereof.

The electromagnetic handwriting input touch system is a general-purpose human interactive device, mainly applied to electronic panel products, with high positioning accuracy, the stylus and touch panel may be connected wirelessly, and the stylus may have no power supply. It has excellent performance such as good. In recent years, it has been widely applied in fields such as human interaction of household electronic products.

The electromagnetic handwriting input touch system is mainly composed of an electromagnetic touch pen (abbreviated as an electromagnetic pen) and an electromagnetic touch panel (abbreviated as an electromagnetic panel). The principle of operation is that the circuit of the electromagnetic pen mainly consists of a resonance circuit, and when the resonance circuit receives the magnetic field signal radiated by the electromagnetic panel coil, one new magnetic field signal is generated at the resonance frequency, and this magnetic field signal is electromagnetically generated. The receiving coil of the panel detects it, and a series of processes obtains information such as pen coordinates and pressure feeling. Here, only when the resonance frequency of the electromagnetic pen matches the frequency of the electromagnetic panel transmission signal, the electromagnetic panel can accurately acquire information such as the coordinates of the pen and the feeling of pressure.

In the prior art, the resonant frequency in the resonant circuit is adjusted by accessing a variable capacitance that changes with pressure in order to match the resonant frequency in the resonant circuit with the pressure change. However, since the capacitor (C) itself has a certain variation, the change value of the capacitor (C) is small at a predetermined resonance frequency, and it cannot react to a writing pressure exceeding a certain range. Alternatively, when the capacitor (C) receives a larger pressure, the resonance frequency tends to exceed the set change range, and the sensitivity of the electromagnetic pen to the initial pressure becomes dull or unrecognizable, so that the pressure of the electromagnetic pen is reduced. The level of perceived accuracy becomes low, and the handwriting effect of the electromagnetic pen deteriorates.

Therefore, it is necessary to solve the above problems by providing a resonance circuit, an electromagnetic pen, and a method for adjusting the capacitance thereof.

At present, in the resonance circuit of the electromagnetic pen of the prior art, the error range of the pressure capacitance is large, the consistency is poor, the pressure recognition range is small, and the handwriting effect is not good. The capacity adjustment method is provided.

The resonant circuit according to the present invention includes an electrically connected inductance and a capacitor, the capacitor has a force sensing capacitor and an adjusting capacitor connected in series, and the adjusting capacitor is provided in parallel. Includes a plurality of fixed-capacity branches and one short branch, each said fixed-capacity branch containing one fixed-capacity and one connecting line, either selectively turning the connecting line on / off or the short branch. By accessing, the capacitance value of the adjusting capacitor is changed, and the consistency of the capacitance value of the capacitor is maintained.
Here, the adjusting capacitor has various access methods, and when the capacitance value of the force sensing capacitor meets the shipping requirements, it is selected to access the short branch, and the capacitance of the force sensing capacitor is selected. If the value does not meet the shipping requirement, the adjusting capacitor chooses to access one or more of the fixed capacitance branches, i.e. turn on the connecting line and the capacitance value of the capacitor is the shipping requirement. The fixed capacitance can be accessed as an adjusting capacitor until it corresponds to.
The resonant circuit further includes a lower key switch, a current transformer, an upper key switch, a first capacitance, a capacitor set, and an electric resistance connected in parallel with the inductor, and each of the capacitor sets. The branch contains one capacitor set connection line, the capacitor set and the first capacitance are both fine-tuned with respect to the capacitor, and the capacitor set connection line is selectively turned on / on. By turning it off, fine adjustment to the capacitor is realized.

The present invention also provides an electromagnetic pen including a brush core, a brush core fixing component, an elastic member, and a PCB plate that abut in order, and the PCB plate includes a resonance circuit as described above.

The present invention also provides a method for adjusting the capacity of an electromagnetic pen having the following steps.
In step S01, an electromagnetic pen comprising a resonant circuit having an inductance and a capacitor electrically connected to the inductance is provided, the capacitor including a force sensing capacitor and an adjusting capacitor, the force sensing capacitor and the adjusting. The capacitors are connected in series and equivalent to the capacitors, the adjusting capacitor comprises a plurality of fixed capacitance branches connected in parallel and one short branch, each said fixed capacitance branch being one fixed. Includes capacitance and one connecting line.
In step S02, the short branch is accessed to the resonance circuit, it is detected whether or not the resonance frequency of the resonance circuit has reached a desired resonance frequency, and if it matches, the process proceeds to step S04, and if it does not match, the step proceeds to step S04. Proceed to S03.
In step S03, the resonant circuit is accessed by accessing the fixed capacitance branch, debugging in the field according to the error range between the capacitor and the standard capacitance, selecting the fixed capacitance branch in order, and accessing the resonant circuit. And it is determined whether the accessed fixed capacitance branch causes the resonant frequency to reach the desired resonant frequency.
In step S04, the short branch or the fixed capacitance branch that has reached the desired resonance frequency is accessed by welding.
Here, in step S03, the fixed capacitance branch in which the accessed resonance circuit cannot reach a desired frequency is removed by dicing the copper foil.

In the resonance circuit of the electromagnetic pen according to the present invention, a force sensing capacitor is connected in series to the adjusting capacitor to make it equivalent to the capacitor, so that the branch to be accessed for the adjusting capacitor is selected and the capacitance due to the manufacturing error is selected. By avoiding poor consistency and limiting the amount of change in the force sensing capacitor, the resonance frequency of the resonance circuit of the electromagnetic pen is ensured not to exceed the required change range. The electromagnetic pen adopting the resonance circuit can generate pressure sensing with good consistency over a wide pressure range, has a good experience effect, and is fixed for capacitance adjustment in which the capacitance values do not match. The capacity value can be flexibly adjusted by selecting the number of capacity branches, which is convenient and accurate to handle. After the capacity of the electromagnetic pen is adjusted, the disposal rate of the electromagnetic pen can be reduced, and the production cost can be reduced.

In order to more clearly explain the technical proposal in the embodiment of the present invention, the drawings indispensable for the description of the embodiment will be briefly introduced below. Obviously, the drawings described below are only a few embodiments of the invention, and one of ordinary skill in the art may obtain other drawings based on these drawings on the premise of no creative labor.

It is an overall block diagram of the electromagnetic pen provided by this invention. It is a schematic diagram of the resonance circuit provided by this invention. It is a figure which shows the 1st Embodiment of the resonance circuit provided by this invention. It is a figure which shows the 2nd Embodiment of the resonance circuit provided by this invention. It is a figure which shows the 3rd Embodiment of the resonance circuit provided by this invention. It is a schematic diagram which shows the circuit of the resonance circuit provided by this invention. It is a flowchart of the capacity adjustment method of the electromagnetic pen provided by this invention.

Hereinafter, the technical solution in the embodiment of the present application will be described clearly and entirely with reference to the drawings in the embodiment of the present application, but the following description is merely an embodiment of the present application and is not all examples. .. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

As shown in FIG. 1, the electromagnetic pen 100 according to the present invention includes a brush core 10, a brush core fixing component 20, an elastic member 30, and a PCB plate 40 that abut in order. The PCB plate 40 is provided with a resonance circuit (not shown). The brush core fixing component 20 is configured to sandwich the brush core 10 in order to prevent the brush core 10 from swinging. The elastic member 30 elastically connects the brush core 10 and the resonance circuit, and imparts a recovery force to the brush core 10 to recover to the original position after transmitting a pressure signal to the resonance circuit. ..

The resonant circuit includes an electrically connected inductance (L) and a capacitor (C). The inductance (L) includes a fixed inductance composed of a magnetic core and a varnish wire wound around the magnetic core. As a high-sensitivity element, the capacitor (C) can convert a pressure into a changing capacitance value. The resonance circuit senses the pressure transmitted by the writing core 10, converts it into a changing capacitance value, processes it, outputs the resonance frequency corresponding to the pressure, and transmits it to the handwriting board. Then, the pressure of the brush core 10 is displayed on the handwriting board. Here, the square of the resonance frequency and the electric capacity is inversely proportional, and its publicity.

サ（Ｃｖ）は、可変コンデンサであり、その容量値を一定の範囲内で調節できる。共振回路にアクセスする前記調節コンデンサ（Ｃｑ）の容量値を選択すること及び前記フォースセンシングコンデンサ（Ｃｖ）に対する調節により、前記コンデンサ（Ｃ）に対する調節が実現される。 In particular, as shown in FIG. 2, FIG. 2 is a circuit schematic diagram of the resonance circuit of the electromagnetic pen provided by the present invention. The resonant circuit includes an inductance (L) and a capacitor (C) electrically connected to the inductance (L). The capacitor (C) includes a force sensing capacitor (Cv) and an adjusting capacitor (Cq) arranged in series, and the equivalent equation thereof is.

The capacitor (Cv) is a variable capacitor, and its capacitance value can be adjusted within a certain range. Adjustment to the capacitor (C) is realized by selecting the capacitance value of the adjusting capacitor (Cq) to access the resonance circuit and adjusting to the force sensing capacitor (Cv).

Specifically, the regulating capacitor (Cq) includes a plurality of fixed capacitance branches and one short branch connected in parallel. Each said fixed capacity branch comprises one fixed capacity and one connecting line. The plurality of fixed capacities are the same or corresponding capacity values. Here, the same capacity value or different capacity values can be selected for the plurality of fixed capacities.

Before the electromagnetic pen is shipped, it is necessary to perform field debugging to determine whether to weld a fixed capacity having a specific capacity value and the number of fixed capacities to be welded. The reason for connecting in series to the adjusting capacitor (Cq) is to adjust the capacitance range of the capacitor (C). Preferably, the capacitance values of the plurality of fixed volumes are different from each other and gradually change. Further, the capacitance value of the adjusting capacitor (Cq) can be selected to be 7 to 20 times that of the force sensing capacitor (Cv).

As shown in FIGS. 3-5, the present invention provides examples of three resonant circuits. The adjusting capacitor (Cq) in the resonant circuit may have a plurality of access methods. When the capacitance value of the force sensing capacitor (Cv) meets the shipping requirements, the short branch is selected, that is, the branch containing only the connection line J is accessed (see FIG. 3). As shown in FIG. 4, the adjusting capacitor (Cq) may choose to access one fixed capacitance branch. That is, the connection line (J1) is turned on, and the fixed capacitance is connected in series as an adjusting capacitor (Cq). In addition to this, as shown in FIG. 5, the adjusting capacitor (Cq) may be accessed by two fixed capacitors in parallel. That is, by turning on the connection lines (J1) and (J2) at the same time, it is possible to access two parallel fixed capacitance branches as an adjusting capacitor (Cq).

Further, referring to FIGS. 2 to 6, in addition to this, the resonance circuit has a lower key switch (K1), a current transformer (CT1), and an upper one connected in parallel with the inductance (L) in order. It further includes a key switch (K2), a _first capacitance (C1), a capacitor set ( _Cn ), and an electrical resistance (R). Each branch of the capacitor set ( _Cn ) includes one capacitor set connection line. Both the capacitor set (C _n ) and the first capacitance (C ₁ ) are finely adjusted with respect to the capacitor, and the resonance frequency is resonated by selectively turning on / off the capacitor set connection line. Is fine-tuned with respect to the capacitor (C) so that

The electromagnetic pen changes its resonance frequency by changing the capacitance value of the capacitor (C) in the resonance circuit. This prevents the resonance frequency of the resonance circuit from exceeding the pass band, improves the accuracy level of the induced pressure of the electromagnetic pen, adapts it to writing at a large pressure, and further in the process of writing by the electromagnetic pen. Make it smooth.

Further, as an application of the resonance circuit, it can be applied not only to the electromagnetic pen but also to other types of electromagnetic pens. For example, an electromagnetic pen having an inductance (L) including a single magnetic core.

It should be noted that any idea that realizes variable adjustment of the capacitance value of the resonance circuit by increasing the series capacitance belongs to the creative purpose of the present invention.

FIG. 7 is a method for adjusting the capacity of the electromagnetic pen shown in FIG. 1, which includes the following steps.

S01 provides an electromagnetic pen comprising a resonant circuit having an inductance (L) and a capacitor (C) electrically connected to the inductance (L). The capacitor (C) includes a force sensing capacitor (C _v ) and an adjusting capacitor (C _q ). The force sensing capacitor (C _v ) and the adjusting capacitor (C _q ) are connected in series and are equivalent to the capacitor (C). The regulating capacitor (C _q ) includes a plurality of fixed capacitance branches connected in parallel and one short branch. Each fixed capacity branch contains one fixed capacity and one connecting line. Here, the force sensing capacitor (C _v ) is provided on the interface (S ₁ ) and corresponds to the pressure received by the pen tip 10. Here, the inductance value of the inductance (L) is selected to be 51 to 52 μH. The number of turns of the varnish wire is preferably 50 turns.

In S02, the short branch is accessed to the resonance circuit, it is detected whether or not the resonance frequency of the resonance circuit has reached a desired resonance frequency, and if it matches, the process proceeds to step S04, and if it does not match, step S03. Proceed to.

In S03, the resonant circuit is accessed by the fixed capacitance branch, debugged in the field according to the error range between the capacitor and the standard capacitance, the fixed capacitance branch is selected in order, and the circuit is accessed and accessed. It is determined whether or not the fixed capacitance branch is brought to the desired resonance frequency.

具体的には、本実施形態では、前記調節コンデンサ（Ｃ_ｑ）は、並列に接続される３つの固定容量ブランチと１つのショートブランチとで構成される。前記固定容量の容量値は、それぞれ２２０ｐＦ、３９０ｐＦ及び１０００ｐＦである。なお、前記調節コンデンサ（Ｃ_ｑ）には、複数の前記固定容量ブランチが並列にアクセスされることが可能である。 That is, when the force sensing capacitor (C _v ) is as close as possible to the set capacitor (C), it can be short-connected to the adjusting capacitor (C _q ). The force sensing capacitor (Cv) and the adjusting capacitor (C _q ) are

Specifically, in the present embodiment, the adjusting capacitor (C _q ) is composed of three fixed capacitance branches and one short branch connected in parallel. The capacitance values of the fixed capacitance are 220pF, 390pF and 1000pF, respectively. It should be noted that the regulating capacitor (C _q ) can be accessed in parallel by the plurality of fixed capacitance branches.

In S04, the short branch or the fixed capacitance branch that has reached the desired resonance frequency is accessed by welding.

Here, in step S03, the fixed capacitance branch in which the accessed resonance circuit cannot reach a desired frequency is removed by dicing the copper foil.

In the debugging process of step S02 and step S03, it is necessary to measure the resonance frequency data of the electromagnetic pen with the number adjusting plate. Specifically, the number adjusting plate realizes the output of frequency data by its serial output function. The computer is connected to the number adjusting plate by a serial data line and acquires the frequency data of the electromagnetic pen in real time to calculate the frequency and select the adjusting capacitor (C _q ).

In the resonance circuit of the electromagnetic pen 100 according to the present invention, the force sensing capacitor (C _v ) is connected in series to the adjusting capacitor (C _q ) to make it equivalent to the capacitor (C), thereby making the adjusting capacitor (C _q ) equivalent. ), By selecting the branch to be accessed, avoiding the inconsistency of the capacitor (C) due to the manufacturing error, and limiting the amount of change of the force sensing capacitor ( _Cv ), the electromagnetic pen. Make sure that the resonance frequency of the resonance circuit does not exceed the required change range. The electromagnetic pen adopting the resonance circuit can generate pressure sensing with good consistency over a wide pressure range, has a good experience effect, and is fixed for capacitance adjustment in which the capacitance values do not match. The capacity value can be adjusted flexibly by selecting the number of capacity branches, which is convenient and accurate to handle. After the capacity of the electromagnetic pen is adjusted, the disposal rate of the electromagnetic pen 100 can be reduced, and the production cost can be reduced.

The above is merely an embodiment of the present application and does not limit the scope of the claims of the present application, and directly or indirectly the equivalent structure or the equivalent process created by using the specification and the drawings of the present application. Anything obtained by applying it to other related technical fields is included in the claims of the present application.

Claims (10)

A resonant circuit consisting of an electrically connected inductance and a capacitor, wherein the capacitor has a force sensing capacitor and an adjusting capacitor connected in series, and the adjusting capacitor is a plurality of fixed capacitors provided in parallel. It contains a capacity branch and one short branch, each said fixed capacity branch containing one fixed capacity and one connecting line.
By selectively turning on / off the connecting line or accessing the short branch, the capacitance value of the adjusting capacitor is changed to maintain the consistency of the capacitance value of the capacitor.
Here, the adjusting capacitor has various access methods, and when the capacitance value of the force sensing capacitor meets the shipping requirements, it is selected to access the short branch.
If the capacitance value of the force sensing capacitor does not meet the shipping requirements, the adjusting capacitor may choose to access one or more of the fixed capacitance branches, i.e. turn on the connecting line and the capacitor. The fixed capacitance can be accessed as an adjusting capacitor until the capacitance value of is applicable to the shipping requirements.
The resonant circuit further comprises a lower key switch, a current transformer, an upper key switch, a first capacitance, a capacitor set, and an electric resistance connected in parallel with the inductor.
Each branch of the capacitor set includes one capacitor set connection line, and both the capacitor set and the first capacitance are fine-tuned with respect to the capacitor, and the capacitor set connection line is used. A resonance circuit characterized in that fine adjustment for the capacitor is realized by selectively turning on / off. The resonance circuit according to claim 1, wherein the force sensing capacitor is a variable capacitor. The resonance circuit according to claim 1, wherein the plurality of fixed capacitances have the same capacitance value. The resonance circuit according to claim 1, wherein the capacitance values of the plurality of fixed capacitances are different from each other and gradually change. The resonance circuit according to claim 1, wherein the capacitance value of the adjusting capacitor is 7 to 20 times that of the force sensing capacitor. An electromagnetic pen provided with a brush core that abuts in order, a brush core fixing component, an elastic member, and a PCB plate.
The electromagnetic pen, wherein the PCB plate includes the resonance circuit according to any one of claims 1 to 5. The electromagnetic pen according to claim 6, wherein the inductance includes a fixed inductance including a magnetic core and a varnish wire wound around the magnetic core. Provided is an electromagnetic pen comprising a resonant circuit having an inductance and a capacitor electrically connected to the inductance, wherein the capacitor includes a force sensing capacitor and an adjusting capacitor, the force sensing capacitor and the adjusting capacitor are in series. Equivalent to the capacitor connected to, the adjusting capacitor comprises a plurality of fixed capacitance branches connected in parallel and one short branch, each said fixed capacitance branch having one fixed capacitance and one. Step S01, which includes two connecting lines, and
The step of accessing the resonance circuit through the short branch, detecting whether or not the resonance frequency of the resonance circuit has reached a desired resonance frequency, and proceeding to step S04 if they match, and proceeding to step S03 if they do not match. S02 and
The resonant circuit was accessed by accessing and accessing the resonant circuit by accessing the resonant circuit, debugging in the field according to the error range between the capacitor and the standard capacitance, and sequentially selecting the capacitive branch. Step S03 to determine whether the fixed capacitance branch causes the resonant frequency to reach the desired resonant frequency.
A step S04, in which a short branch or a fixed capacitance branch that has reached a desired resonance frequency is accessed by welding, is provided.
Here, in step S03, a method for adjusting the capacitance of the electromagnetic pen, which comprises dicing a copper foil to remove the fixed capacitance branch in which the accessed resonant circuit cannot reach a desired frequency. The method for adjusting the capacitance of an electromagnetic pen according to claim 8, further comprising a number adjusting plate in steps S02 and S03, and using the number adjusting plate to debug the resonance frequency of the electromagnetic pen in the field. .. The capacitance adjusting method according to claim 8, wherein in step S03, the number of the fixed capacitance branches accessed by the resonance circuit is a plurality, and the plurality of fixed capacitance branches are connected in parallel. ..

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