KR101664329B1 - Compensation Method of Force Sensing Capacitance and Force Input Sensing Apparatus using thereof - Google Patents

Abstract

The force input detecting device according to the present embodiment includes a cover window deformed by a force input provided from an object and a force detection layer which is one electrode of a force sensing capacitor whose capacitance value changes according to deformation of the cover window and a force input detecting unit for detecting a force input, wherein the force input detecting unit comprises: a compensation capacitor for compensating the force sensing capacitor; a switching unit for switching an electrical connection form of the force sensing capacitor and the compensation capacitor; And a detection circuit section that detects an electrical signal that changes in accordance with a change in the capacitance value of the force sensing capacitor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a force sensing capacitance compensation method and a force input sensing device using the same,

The present invention relates to a force sensing capacitance compensation method and a force input detection apparatus using the same.

Currently, sensing methods used in touch screens are mainly composed of resistive film type, surface ultrasonic type, and capacitance type. In case of capacitive type, multi-touch detection is possible and durability and visibility are excellent. And is adopted as an input means.

The capacitive touch screen recognizes the user input by sensing the change in the amount of charge charged on the capacitive sensors on the touch screen panel due to user intervention, and recognizes the user input by self-capacitive type according to the charge storage method. And mutual-capacitive. The self-capacitance scheme forms one conductor per capacitive sensor to form a reference ground and a charging surface outside the touch screen panel, while the mutual capacitive scheme provides two reference electrodes on the touch screen panel Of the electric conductors form a charging surface to function as one charging sensor.

A prior patent for such a capacitive touch sensitive panel is US Pat. No. 7,920,129.

The touch panel according to the related art has a function of detecting coordinates of a single or a plurality of touches by an object to which a touch input is applied, locus detection formed by touching the panel, object detection for hovering the touch panel, A force sensing device is added, or a force input provided by a user pressing the touch panel by the touch panel itself has been detected.

There is a method of detecting by using a change in capacitance value, as one of a method in which a user applies input to a force sensing device to detect an input. The capacitance value of an intrinsically inherent capacitor in a conventional force sensing device is larger than a capacitance change caused by a force input provided by a user. Capacitance values of parasitic capacitances and force sensing capacitors continue to increase with the progress of miniaturization and thinning of electronic products. However, since the capacitance variation caused by a user applying force to the touch panel is decreasing, It is becoming increasingly difficult to detect the signal with a degree of accuracy and sensitivity that can be ensured.

The present embodiment is for solving the problems of the above-mentioned prior art. One of the goals of this embodiment is to provide a method and apparatus that can improve the accuracy and sensitivity of input detection using a force sensing layer that can reduce the capacitance value of a capacitor inherently embedded in a force input device. One of the objects of the present embodiment is to provide a method and an apparatus that can compensate for the influence of the parasitic capacitance formed in the input providing means so as to enhance the accuracy and sensitivity of the input detection that the user applies to the input providing means.

The force input detecting device according to the present embodiment includes a cover window deformed by a force input provided from an object and a force detection layer which is one electrode of a force sensing capacitor whose capacitance value changes according to deformation of the cover window and a force input detecting unit for detecting a force input, wherein the force input detecting unit comprises: a compensation capacitor for compensating the force sensing capacitor; a switching unit for switching an electrical connection form of the force sensing capacitor and the compensation capacitor; And a detection circuit section that detects an electrical signal that changes in accordance with a change in the capacitance value of the force sensing capacitor.

(A) precharging a force sensing capacitor formed of a force sensing layer, a reference sensing electrode, and a compensation capacitor to a supply voltage, and (b) ) Performing a first charge sharing by serially connecting a positive-sense capacitor and a compensation capacitor between a supply voltage and a reference voltage, and (c) performing a first charge sharing with the positive-sense capacitor and the compensation capacitor Performing charge sharing on the first charge sharing voltage, and (d) outputting a second charge sharing formed voltage.

According to the present embodiment, there is provided an advantage that the force input can be detected with high accuracy and high sensitivity as compared with the prior art by compensating the capacitance value of the capacitor inherently embedded in the force input detecting device.

Fig. 1 (a) and Fig. 1 (b) are sectional views showing the outline of the force input detecting device according to the present embodiment, and Fig. 2 is a block diagram showing an outline of the force input detecting device according to the present embodiment.
3 is a diagram showing an outline of a force detection layer.
4 is a diagram showing an embodiment of the detection circuit section.
5 (a) is a view showing a state where a force sensing layer and a metal body are separated from each other, which is one electrode of a force sensing capacitor in a state where a force input is not provided, and FIG. 5 (b) A state of a sensing layer and a metal body.
6 is a flowchart schematically showing each step of the force detection capacitance compensation method according to the present embodiment.
7 is an exemplary timing chart showing control signals that the control unit provides to the switching unit.
FIGS. 8 and 9 are diagrams showing equivalent circuits for each phase in which the control unit drives the switching unit. FIG.

The description of the present invention is merely an example for structural or functional explanation, and the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas.

Meanwhile, the meaning of the terms described in the present application should be understood as follows.

The terms " first ", " second ", and the like are used to distinguish one element from another and should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "on" or "on" another element, it may be directly on top of the other element, although other elements may be present in between. On the other hand, when an element is referred to as being "in contact" with another element, it should be understood that there are no other elements in between. On the other hand, other expressions that describe the relationship between components, such as "intervening" and "intervening", between "between" and "immediately" or "neighboring" Direct neighbors "should be interpreted similarly.

It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it is present and not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

Each step may take place differently from the stated order unless explicitly stated in a specific order in the context. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

The drawings referred to for explaining embodiments of the present disclosure are exaggerated in size, height, thickness, and the like intentionally for convenience of explanation and understanding, and are not enlarged or reduced in proportion. In addition, any of the components shown in the drawings may be intentionally reduced, and other components may be intentionally enlarged.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms such as those defined in commonly used dictionaries should be interpreted to be consistent with the meanings in the context of the relevant art and can not be construed as having ideal or overly formal meaning unless explicitly defined in the present application .

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 (a) and Fig. 1 (b) are sectional views showing the outline of the force input detecting device according to the present embodiment, and Fig. 2 is a block diagram showing an outline of the force input detecting device according to the present embodiment. 1 (a), 1 (b), and 2, the force input detecting device according to the present embodiment includes a cover window 110 deformed by a force input provided from an object, A force sensing layer 150 which is one electrode of a force sensing capacitor Cf whose capacitance value changes according to the deformation of the cover window, and a force input detecting unit which detects a force input, The force input detecting unit includes: a compensation capacitor Cc for compensating the force sensing capacitor; a switching unit 200 for switching the electrical connection between the force sensing capacitor Cf and the compensation capacitor Cc; And a detection circuit unit 300 that detects an electrical signal that changes in accordance with a change in the capacitance value of the force sensing capacitor Cf. In one embodiment, the force input detecting apparatus according to the present embodiment further includes a control unit 400 for controlling a switch included in the switch unit 200. [

Hereinafter, the thing that a user can apply a force input to a force input detecting device is defined as an " object ". Such an object can mean an object, such as a finger or a palm, or a part of the user's body or a stylus, and means that the cover window 110 can be modified to provide a force input. The above example is for explaining an object, not for limiting the scope of the object.

1 (a) and 1 (b), the force input detecting device according to the present embodiment includes a cover window 110 deformed by a force input provided from an object. The cover window 110, in one embodiment, is formed of a transparent material capable of transmitting the image provided by the display unit 130 to provide an image to the user. As another example, when the force input detecting apparatus does not include the display unit 130, it may be formed of an opaque material. In one embodiment, the cover window 110 is formed of tempered glass. In another example, the cover window 110 is formed of a synthetic resin such as polycarbonate, acrylic, or the like.

In one embodiment, the force input detection device may include a touch sensing layer 120 for detecting a touch input. The touch detection layer 120 may include a dielectric substrate, a driving electrode disposed on one surface of the dielectric substrate, and a sensing electrode or a dielectric substrate disposed on the other surface of the dielectric substrate, And detects the touch input by a mutual capacitance type including the driving electrode and the sensing electrode.

In another example, the touch detection layer 120 detects a touch in a self-capacitance type. The first electrode and the second electrode may be formed on the dielectric substrate. The first electrode and the second electrode may be formed on the dielectric substrate. The capacitance formed by the touching object and the first electrode, the capacitance between the object and the second electrode, .

In one embodiment, the bodies 140a and 140b have a space in which the force sensing layer 150 or the like can be embedded, and are covered by the cover window 110. [ The metal body 140a is formed of a conductive metal as illustrated in Fig. 1 (a) and functions as an electrode of the force sensing capacitor Cf. In one example, the metal body 140a may be electrically connected to a reference potential. According to the embodiment illustrated in FIG. 1 (b), the body 140b may be formed of an insulator such as a synthetic resin.

The display unit 130 displays an image to the user. The display unit may be, for example, an LCD (Liquid Crystal Display) panel. As another example, the display portion may be an OLED (Organic Light Emitting Device) panel. A reference electrode provided with a reference potential may be included in the display portion. In the embodiment shown in FIG. 1 (b), one electrode included in the display unit 130 may form a force sensing capacitor Cf together with the force sensing layer 150.

A force sensing layer 150 is one electrode of the force sensing capacitor Cf and is deformed according to the deformation of the cover window 110 by the force input by the object. FIG. 3 is a diagram showing an outline of the force sensing layer 150. FIG. Referring to FIG. 3, the force sensing layer 150 includes a conductive pattern having a porous structure. The area of the central hole H ₁ is larger than the area of holes H ₂ and H ₃ located in the peripheral area And the area of the hole is smaller as the distance from the center is larger. The force sensing layer 150 may be formed of a conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum Zinc Oxide), ICO Oxide) and carbon nanotube film (CNT).

In the embodiment shown in FIG. 1 (a), the two electrodes of the force sensing capacitor Cf may be the force sensing layer 150 and the metal body 140a. For example, the metal body 140a may be electrically connected to a reference potential. 1 (b), when the body 140b is formed of a nonconductor such as a synthetic resin, the force sensing layer 150 may be connected to one end of the force sensing capacitor Cf ) Can be formed. The force sensing layer 150 is disposed on the nonconductive body and the display portion 130 is attached to the touch sensing layer 120 to form the force sensing layer 150 and one electrode of the display portion 130, And the force sensing capacitor Cf can be formed.

The capacitance value of the capacitor composed of two electrodes can be calculated as shown in Equation 1 below.

Referring to Equation (1), as the distance between the two electrodes approaches, the capacitance value increases. As the area of the electrode decreases, the capacitance value decreases. Therefore, the force sensing layer 150 can be formed in a porous structure to reduce the area of the electrode forming the capacitor, thereby reducing the capacitance value of the force sensing capacitor Cf. Also, as the object provides a force input and the cover window 110 and the bodies 140a and 140b approach, the distance between the two electrodes becomes close to increase the capacitance value of the force sensing capacitor Cf.

Hereinafter, the inherent capacitance implies not only the capacitance of an intended formed capacitor but also the capacitance of an existing capacitor. For example, in the embodiment shown in FIG. 1 (a), the force sensing capacitor Cf is a capacitor formed by the force sensing layer 150 and the metal body 140, or the capacitance of an essentially inherent capacitor, The capacitance of the parasitic capacitor formed between the force sensing layer 150 and the display portion 130 as well as the capacitance of the force sensing capacitor Cf and the parasitic capacitance formed between the force sensing layer 150 and the touch sensing layer 120 The capacitance of the capacitor, and the like.

The switching unit 200 is electrically connected to the force sensing capacitor Cf and includes a plurality of switches S1a, S1b, S2, S3, S4 and S5 and a compensation capacitor Cc. The plurality of switches S1a, S1b, S2, S3, S4 and S5 are controlled by a signal provided by the control unit 400 and may be a field effect transistor (FET) or a bipolar junction Transistor) or the like. The switches S1a and S1b are turned on and off by the same control signal S1. The compensating capacitor Cc compensates the capacitance of the force sensing capacitor Cf through two charge sharing processes as will be described later so that it is possible to easily detect the influence of the increased capacitance? .

For example, the first supply voltage Vdd1 provided to the switching unit 200 may be a voltage formed by multiplying the second supply voltage Vdd2 provided to the detection circuit unit 300 or the like by a charge pump (not shown) or a voltage And a second supply voltage supplied to the inside of the chip by a multiplier (not shown). The first supply voltage Vdd1 may be supplied to the force sensing capacitor Cf to increase the amount of charge charged in the force sensing capacitor Cf, thereby improving the force input detection performance. One electrode and the other electrode of the compensation capacitor (Cc) are connected to the n1 node and the n2 node, respectively. The compensating capacitor Cc performs a function of compensating the capacitance of the force sensing capacitor Cf as will be described later.

Although not shown, the switching unit 200, the detection circuit unit 300, and the control unit 400 may be formed for each channel of the sensing electrode included in the touch input detection device. Also, the n1 node and the n2 node of the switching unit may be electrically connected to the switches controlled by the control unit 400, respectively, so that the compensation capacitors included in the switching unit 200 formed for each channel can be electrically connected to each other. As described later, the compensation capacitor Cc may be connected in parallel with compensation capacitors of a plurality of channels to form a compensation capacitor having a larger equivalent capacitance than each compensation capacitor.

Fig. 4 is a diagram showing an embodiment of the detection circuit unit 300. Fig. The detection circuit unit 300 includes an amplifier 310 that receives and amplifies the electrical signal vn1. The capacitance value of the force sensing capacitor Cf changes according to the force input provided by the object O and the amplifier receives and amplifies the electric signal vn1 formed by the capacitance value change DELTA CF to form the output signal v do.

An amplifier 310 amplifies the input signal with a predetermined gain. The amplifier can be used in the force input detecting device according to the present embodiment regardless of its configuration and configuration as long as it is an amplifier capable of receiving and amplifying an electric signal. As an example, the amplifier may be a single ended amplifier, or as another example, a differential amplifier may be used to amplify the difference from the electrical signal in relation to the predetermined potential or ground potential with the amplifier.

In one embodiment, the detection circuitry 300 may further include an analog-to-digital converter (ADC) 330. The analog-to-digital converter can convert the signal provided by the amplifier 310 into a digital signal and provide it to a digital signal processing unit to perform subsequent signal processing.

In one embodiment, the detection circuit section 300 is provided with a second supply potential Vdd2 different from that of the switching section 200 and operates. The detection circuit unit 300 may include an analog-to-digital converter (ADC) or the like. Therefore, if they are formed to operate at the first supply potential formed by multiplying the second supply potential, the required die area is increased, which is uneconomical. Therefore, the detection circuit unit 300 is implemented to be driven with the second supply potential lower than the first supply potential in order to reduce the area consumption required for implementing the function. As another example, it is possible to design the detection circuit section 300 to operate at the first supply potential for simple circuit design.

Hereinafter, a method of compensating a force sensing capacitor and an operation of a force input detecting apparatus using the force sensing capacitor will be described with reference to FIGS. 5 (a), 5 (b) 5A shows a state in which the force sensing layer 150, which is one electrode of the force sensing capacitor Cf, and the metal body 140a are spaced apart from each other in a state in which the force input is not provided in the embodiment shown in FIG. And FIG. 5B is a view showing states of the force sensing layer 150 and the metal body 140a in a state in which a force input is provided. As shown in FIG. 5 (a), the force sensing layer 150 and the metal body 140a are spaced apart by d1 before the force input is provided. When the object O provides a force input, the cover window 110 is deformed as illustrated in FIG. 5 (b), and accordingly, the force sensing layer 150 is also deformed. As the force sensing layer 150 approaches the metal body 140a, the minimum spacing distance decreases to d2 and the average spacing distance between the force sensing layer 150 and the metal body 140a also decreases. As the spacing between the one electrode of the force sensing capacitor Cf and the other electrode decreases, the capacitance of the force sensing capacitor Cf increases as a result of Equation (1).

1 (b), the force sensing layer 150, which is one electrode of the force sensing capacitor Cf as the force input is provided, is connected to the display unit 130, which is the other electrode of the force sensing capacitor Cf, The capacitance of the force sensing capacitor Cf increases. According to an embodiment not shown, the display unit 130 including the other electrode of the force sensing capacitor Cf is provided with the force sensing layer 150, which is one electrode of the force sensing capacitor Cf, The capacitance of the force sensing capacitor Cf increases.

When the amount of capacitance increase of the force sensing capacitor Cf by the force input is denoted by? Cf, the equivalent capacitance electrically connected to the switching unit 200 is Cf +? Cf which is the sum of the force sensing capacitor Cf and the capacitance increase amount? Accordingly, the equivalent capacitance connected to the switching unit 200 when the force input is not provided is Cf, and the equivalent capacitance when the force input is provided is Cf +? Cf, the equivalent capacitance connected to the switching unit 200.

The capacitance Cf of the force sensing capacitor is larger than the increased capacitance? Cf, so it is difficult to detect the capacitance variation? Cf within a range effective for the force sensing device according to the related art. According to the present embodiment, the capacitance of the force sensing capacitor can be compensated by the following process.

6 is a flowchart schematically showing each step of the force detection capacitance compensation method according to the present embodiment. Referring to FIG. 6, the method for compensating for the positive detection capacitance according to the present embodiment includes a step S100 of precharging a force sensing capacitor and a compensation capacitor to a supply voltage, (S200) of performing a first charge sharing by connecting a positive sense capacitor and a compensation capacitor in series between the positive charge sharing capacitor and the compensation capacitor, charge sharing (S300), and outputting a voltage formed by the second charge sharing (S400).

7 is an exemplary timing diagram showing control signals that the control unit 400 provides to the switching unit 200. As shown in FIG. Referring to FIG. 4, the controller 400 controls the switching unit 200 to select one of a precharge phase P1, a first charge sharing phase P2, a second charge sharing phase P3, and an output phase P4 . In one embodiment, the control unit 400 may drive the switching unit 200 in the pre-charge phase P1 again after the output phase P4.

Referring to the area indicated by the dotted line in FIG. 7, the controller 400 controls each boundary of each phase in order to prevent unintentional leakage or sharing of the charges charged in the respective capacitors during the conduction and blocking of the switch Thereby forming control signals such that the signals do not overlap each other.

In the embodiment shown in FIG. 7, switches included in the switching unit 200 are implemented by NMOS (N type MOS) switches. Therefore, when the control electrode of each switch is supplied with a high-state signal, it is conducted, and when the low-state signal is supplied, it is interrupted. However, this may be implemented by using a PMOS (P type MOS) switch which is conducted when a low-level signal is provided to the control terminal and is blocked when a high-level signal is provided, Or to provide NPN BJTs or PNP BJTs that provide conduction and blocking by providing negative currents.

8 and 9 are diagrams showing equivalent circuits for each phase at which the control unit 400 drives the switching unit 200. As shown in FIG. 8A is a diagram showing an equivalent circuit when the switching unit 200 is driven by the precharge phase P1. Referring to FIGS. 6 to 8 (a), the switches S1a, S1b and S4 of the switching unit 200 are turned on in the P1 step (precharge phase) of FIG. 7, and the remaining switches are controlled to be turned off. Therefore, the switch unit 200 and the touch panel 100 form an equivalent circuit of Fig. 8A. The force sensing capacitor Cf + [Delta] Cf and the compensation capacitor Cc having a capacitance increase amount of [Delta] Are all charged with the first supply potential Vdd1 (S100). In an equivalent circuit, the compensation capacitor Cc and the force sensing capacitor Cf +? Cf are connected in parallel. The parallel capacitor Cc and the force sense capacitor Cf +? Cf are provided with a first supply potential at each node, and each of the other nodes is connected to the ground potential, so that they are both charged to the first supply potential.

8 (b) is a diagram showing an equivalent circuit when the switching unit 200 is driven by the first charge sharing phase P2. Referring to Figs. 6, 7 and 8 (b), in the first charge sharing phase P2, the switches S2 and S4 are turned on and the remaining switches are turned off. In the equivalent circuit, the compensation capacitor Cc and the force sensing capacitor Cf + [Delta] Cf are connected in series between the first supply potential Vdd1 and the ground potential. Charges charged in the compensation capacitor Cc and the force sensing capacitor Cf +? Cf in the precharge phase P1 are distributed in the first charge sharing phase P2 (S200). The voltage Vn that is distributed in the first charge sharing phase P2 and formed in the force sensing capacitor Cf +? Cf is represented by? In Equation 2.

Since the capacitance increase ΔCf of the force sensing capacitor is negligible compared with the capacitance of the force sensing capacitor and the capacitance of the compensating capacitor Cf + Cc, the equation (1) can be approximated as in (2). For example, if the second supply voltage Vdd2 provided to the amplifier is 2V, the first supply voltage Vdd1 is 9V, the capacitance of the force sensing capacitor Cf is 100pF and Vn is 1V, which is half of the second supply voltage The capacitance Cc of the compensating capacitor should be 800 pF. However, the capacitance of 800 pF is not economical because the die size consumption is large when the chip is formed inside the chip.

9A is a diagram showing an equivalent circuit when the switching unit 200 is driven by the second charge sharing phase P3. 6, 7 and 9 (a), in the second charge sharing phase P3, the switches S2 and S5 are turned on and the remaining switches are controlled to be turned off (S300). Charges charged in the compensation capacitor Cc and the force sensing capacitor Cf +? Cf in the first charge sharing phase P2 are distributed again in the second charge sharing phase P3 (S300). The voltage Vn formed in the parallel capacitor Cp + Cc in the second charge sharing phase P3 is expressed by Equation 3.

In Equation (3), the capacitance increase amount? Cf of the force sensing capacitor is negligibly smaller than the capacitance of the force sensing capacitor and the capacitance sum of the compensation capacitor Cf + Cc, so that Equation? Can be approximated as Equation have. If the force sensing capacitor Cf is 100 pF and Vn is 1 V, which is half of the second supply voltage Vdd2, which is the same condition as in the first charge sharing phase in Equation (2) of Equation 3, Cf), a capacitor having a capacitance of 80 pF is required, which is not a problem for forming in the chip. In one embodiment, the output voltage Vn of the switching unit 200 may be adjusted to a specific voltage value by adjusting the capacitance of the compensation capacitor as described above.

In one embodiment, the switching unit 200, the detection circuit unit 300, and the control unit 400 included in the force input detection device according to the present embodiment may be formed for each channel of the sensing electrode included in the touch input detection device For example, an object hovering the touch panel can be detected. When the capacitance value obtained by calculating the equation (2) in Equation (3) is obtained as a large value for mounting in the chip, the controller 400 controls the switches (not shown) Connect the capacitors in parallel with each other. Thus, a compensation capacitor having an equivalent capacitance value greater than the capacitance of the compensation capacitor formed for each channel can be formed. Also, the capacitance of the equivalent compensation capacitor can be actively controlled by adjusting the number of capacitors connected in parallel according to the result of equation (2) in Equation (3).

The force input detecting apparatus according to the present embodiment may be fixedly installed in any one place, and may be installed in a mobile phone, a tablet, a notebook computer, or the like, and the position may be changed. In addition to the case where the position is fixed, the capacitance value may increase or decrease due to changes in ambient temperature, humidity or the like even when the position is fixedly disposed at any one place. The change in the capacitance value can reduce the detection performance for the force input. However, according to the present embodiment, there is provided an advantage that the detection performance of the force input can be improved by actively coping with the capacitance which varies depending on the environment and the position of the force input detecting device.

Further, the force input detecting device according to the present embodiment can compensate the force sensing capacitor Cf through the precharge phase and the two charge sharing phases. This provides the advantage of being able to detect the force input with higher sensitivity and precision.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It will be appreciated that other embodiments are possible. Accordingly, the true scope of the present invention should be determined by the appended claims.

110: cover window 120: touch detection layer
130: Display part 140a: Metal body
140b: insulated body 150: force sensing layer
200: switching part 300: detection circuit part
400:
S100 to S400: Each step of the force sensing capacitance compensation method according to the present embodiment

Claims (17)

(a) precharging a force sensing capacitor and a compensation capacitor to a supply voltage,
(b) performing a first charge sharing by serially connecting the force sensing capacitor and the compensation capacitor between the supply voltage and the reference voltage,
(c) performing a second charge sharing such that the force sensing capacitor and the compensation capacitor have the same voltage, and
(d) outputting the voltage formed by the second charge sharing,
The force sensing capacitor
A force sensing capacitance compensation method using a force sensing layer as a conductive pattern having a porous structure as one electrode. delete The method according to claim 1,
The porous structure may comprise:
Wherein the area of the central region hole is larger than the area of the peripheral area hole. The method according to claim 1,
Wherein the compensation capacitor is formed by connecting a plurality of capacitors in parallel. The method according to claim 1,
Wherein the force sensing capacitor and the compensation capacitor are connected in parallel to each other so that the voltages of the nodes to which the force sensing capacitor and the compensation capacitor are connected have the same voltage. The method according to claim 1,
Wherein the capacitance value of the compensation capacitor is a value set such that the voltage is at a desired level. The method according to claim 1,
Wherein the step of outputting the voltage comprises:
Performing the voltage by providing the detection circuit section,
Wherein the detection circuit unit receives the voltage, amplifies the voltage to a predetermined gain, and converts the amplified signal into a digital signal. A cover window deformed by a force input provided from an object;
A force sensing layer which is one electrode of the force sensing capacitor whose capacitance value changes according to the deformation of the cover window; And
And a force input detecting section for detecting the force input,
The force input detecting unit includes:
A compensation unit for compensating the force sensing capacitor, a switching unit for switching an electrical connection form between the force sensing capacitor and the compensation capacitor, and a control unit for detecting an electrical signal that changes in accordance with a change in the capacitance value of the force sensing capacitor And a detection circuit section
The force sensing layer
A force input detecting device as a conductive pattern having a porous structure. 9. The method of claim 8,
The force input detecting device includes:
Further comprising a metal body,
And the other electrode of the force sensing capacitor is the metal body. 9. The method of claim 8,
The force input detecting device includes:
Further comprising a display unit for displaying an image,
And the other electrode of the force sensing capacitor is one of electrodes included in the display unit. delete 9. The method of claim 8,
The porous structure may comprise:
Wherein the diameter of the central site hole is larger than the diameter of the peripheral area lifespan. 9. The method of claim 8,
The form of electrical connection between the force sensing capacitor and the compensation capacitor
Wherein the force sensing capacitor and the compensation capacitor are coupled to be precharged to a supply voltage. 9. The method of claim 8,
The form of electrical connection between the force sensing capacitor and the compensation capacitor
And a mode in which the force sensing capacitor and the compensation capacitor are connected in series and charge-shared between a supply voltage and a reference voltage. 9. The method of claim 8,
The form of electrical connection between the force sensing capacitor and the compensation capacitor
The force sensing capacitor, and the compensation capacitor are connected in parallel so as to be charge-shared. 16. The method of claim 15,
Wherein the switching unit is switched to provide the charge sharing formed voltage to the detection circuit unit. 9. The method of claim 8,
The detection circuit section,
An amplifier for amplifying and outputting the electrical signal; and an analog-to-digital converter for converting the amplified signal to digital.

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