KR101564069B1

KR101564069B1 - Hovering Object Detection Method, Hovering Object Detection Apparatus using the Same, Switching Matrix and Compensation Capacitance Detection Apparatus

Info

Publication number: KR101564069B1
Application number: KR1020150074139A
Authority: KR
Inventors: 이승욱; 임병상; 이정우
Original assignee: (주)멜파스; 엔플래닉 주식회사
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2015-10-29

Abstract

The hovering object detecting method according to the present embodiment includes the steps of precharging a parallel capacitor and a compensation capacitor connected in parallel with a self-capacitor and a panel electrode capacitor formed between an object hovering the touch panel and electrodes of the touch panel, A first charge sharing step of sharing a charge by connecting a parallel capacitor and a compensation capacitor in series, a second charge sharing step of sharing charge by connecting the parallel capacitor and the compensation capacitor in parallel, And detecting an electrical signal provided by the parallel capacitor while the compensation capacitor is connected in parallel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hovering object detection method, a hovering object detection method, a switching matrix, and a compensation capacitance determination method using the same,

The present invention relates to a hovering object detection method, a hovering object detection apparatus using the same, a switching matrix and a compensation capacitance determination method.

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 charge plane outside the touch screen panel, while the mutual capacitive scheme forms two reference electrodes on the touch screen panel Of the electric conductors form a charging surface to function as one charging sensor.

In general, the self-capacitance type uses an X / Y orthogonal arrangement of conductors. In this case, each power sensor functions as a line sensor. Therefore, when sensing each touch screen, an X- Detection information and Y-sense information from only one Y-line sensor group and one Y-line sensor group, respectively. Thus, a typical self-capacitance touchscreen can detect and track a single touch but not multiple touches. The reciprocal capacitance method uses the X / Y orthogonal arrangement of conductors, but each charging sensor is configured in the form of a grid sensor at each orthogonal position of the conductor. When the user input on the touch screen is detected, The point that is detected independently is different from the self-capacitance method. Each lattice sensor corresponds to a different X / Y coordinate and provides independent reaction results. Therefore, in the mutual storage type touch screen, the user inputs from the X / Y-sense information set provided from the X / Information can be extracted and the multi-touch of the user can be detected and tracked.

Typical mutual capacitance touchscreen panel conductor configurations and sensing methods are as follows. The first electrodes composed of a conductor extending in one direction and the second electrodes composed of a conductor extending in a direction perpendicular to the first electrodes are connected to each other through a dielectric material between the two electrodes, to form a mutual-capacitive sensor. The capacitance C of this sensor is defined as the distance d between two electrodes, the area a of the charge surface, and the dielectric constant ε of all the dielectric materials present between the charge surfaces, C = ε × a / d, the charge Q accumulated in the sensor, and the voltage V and Q = CV applied to the two electrodes / the charge surface. When the user approaches the sensor, interference occurs in the electric field formed between the two electrodes, which prevents the charge from accumulating in the sensor. As a result, the amount of charge stored in the sensor is reduced, resulting in a decrease in capacitance. It can be understood that the capacitance changes due to the change of the equivalent dielectric constant between the charged surfaces due to the user's approach. However, the fact that a portion of the electric field between the charged surfaces is shunted by the user approach, Phenomenon. When an AC voltage source is connected to the first electrode and an AC waveform is applied to one charging surface of the sensor, a charge amount variation (Q) corresponding to DELTA Q = C DELTA Q is generated with respect to C variable depending on the access degree of the user, A read-out circuit (read-out circuit) connected to the second electrode converts the current or voltage. The converted information is generally used for a coordinate tracking algorithm and a gesture recognition algorithm through signal processing steps such as noise filtering, demodulation, digital conversion, and accumulation.

Prior art patents relating to the construction of the touch screen panel and the configuration of the electrodes are U.S. Patent No. 7,920,129.

The conventional touch detection apparatus developed to detect multi-touch from a single touch, but stopped detecting objects touching the surface of the apparatus. To overcome these limitations, the touch detection device has advanced to detecting objects hovering on the device surface without touching the device surface.

The reciprocal capacitance method is a method in which an object touches and absorbs an electric field in which an object is formed on a driving electrode and a sensing electrode, and detects a change thereon. Therefore, it is difficult to detect objects floating in the touch sensing device surface without touching the surface of the touch sensing device by electrostatic capacitive sensing.

A method of detecting a hovering object is preferably a self capacitance method of detecting a capacitance formed between one electrode of a touch panel and an object hovering. However, the change in the capacitance formed between the driving electrode and the moving object as the hovering object moves is several tens to several hundreds of fF, which is 1/10 to 1/100 of the capacitance difference to be detected in the mutual capacitance method. Furthermore, as the touch panel is becoming smaller and thinner, the parasitic capacitance between the electrode and the ground and the parasitic capacitance between the electrode and the electrode, as well as the electrical resistance of the electrode, are several hundreds to several tens of times greater than the capacitance value formed by the hovering object. Therefore, according to the related art, it is difficult to overcome the influence of the parasitic capacitance and to detect the object hovering.

The object of the present embodiment is to solve the above-described problems of the present embodiment, and to provide a detection device capable of detecting an object hovering in a magnetic capacitance manner and efficiently detecting a small change in capacitance.

One of the objects of the present invention is to provide a detecting device capable of detecting an object hovering in a magnetic capacitance manner, and minimizing the influence of parasitic capacitance, thereby detecting a capacitance change due to a hovering object with high sensitivity.

One of the objects of the present invention is to provide an apparatus for detecting the hovering object with a high accuracy and reducing the influence of the parasitic capacitance despite the parasitic capacitance change due to the environmental change in which the hovering object detecting apparatus is located.

The hovering object detecting apparatus according to the present embodiment includes a touch panel having an electrode capacitor, and a compensation capacitor for compensating the electrode capacitor, the electrode including an electrode constituting a self-capacitor together with a hovering object, And a detection circuit for detecting an electrical signal that varies depending on whether the hovering object is accessed or not. The switching unit includes a parallel capacitor connected in parallel with the self capacitor and the electrode capacitor, Precharging the compensation capacitors, performing a first charge sharing by connecting them in series, performing a second charge sharing by connecting the parallel capacitor and the compensation capacitor in parallel, and applying an electrical signal from the self capacitor And provided to the detection circuit unit.

The switching matrix according to this embodiment is a switching matrix provided with a supply power supply potential and a first reference potential, the switching matrix comprising: a plurality of switches; a node electrically connected to the input and the output; And a control unit for controlling a second capacitor and a plurality of switches connected to the node, the control unit comprising: a first capacitor having a first reference potential connected to the first reference potential and a second capacitor connected to the node, A second phase for controlling the plurality of switches to couple the supply power supply potential, the second capacitor and the first capacitor in series, and a second phase for controlling the first and second capacitors and the second capacitor in parallel And the third phase is controlled so as to control the plurality of switches.

The compensation capacitance determination apparatus according to the present embodiment includes an electrode constituting a self-capacitor together with a hovering object, wherein the electrode includes a touch panel having a parasitic capacitor and a compensation capacitor for compensating the parasitic capacitor, wherein the self- And a compensation circuit part for determining a capacitance of the switching part and the compensation capacitor connected in series or in series, wherein the compensation circuit part comprises: a capacitor array including a plurality of capacitors; and a plurality of capacitors, And a control circuit which controls the switches to control the equivalent capacitance of the capacitor array and includes a detection circuit for forming an electrical signal in accordance with a change in the equivalent capacitance, wherein the control part controls the electrical signal according to the change of the equivalent capacitance within a predetermined range Etc. It determines a capacitor having a capacitance as a compensation capacitor.

According to the present embodiment, parasitic capacitance is overcome, and the object hovering without touching the touch panel can be effectively detected.

In addition, according to the present embodiment, it is possible to reduce the influence of the parasitic capacitance despite the change of the parasitic capacitance due to the change of the environment where the hovering object detecting apparatus is located, and to detect the hovering object with high accuracy.

1 is a diagram showing an outline of a hovering object detecting apparatus according to the present embodiment.
2 is a flowchart showing an outline of a hovering object detection method according to the present embodiment.
3 is a view showing an embodiment of the detection circuit section.
4 is an exemplary timing diagram showing control signals that the control unit provides to the switch unit.
5 and 6 are diagrams showing equivalent circuits for each phase in which the control unit drives the switch unit.
7 is a diagram for explaining a compensation capacitance determination apparatus.

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, but 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 is a diagram showing an overview of a hovering object detecting apparatus according to the present embodiment, and FIG. 2 is a flowchart showing an outline of a hovering object detecting method according to the present embodiment. 1, a hovering object detecting apparatus according to the present embodiment includes a touch panel 100 including electrodes constituting a self-capacitor Cs together with a hovering object O, and electrodes are connected to a parasitic capacitor And a compensation capacitor Cc for compensating the parasitic capacitor. The switching unit 200 connects the parallel capacitor connected in parallel with the self-capacitor and the parasitic capacitor in parallel with the compensation capacitor or connects the compensation capacitor in series with the compensation capacitor, And a detection circuit unit 300 that detects an electrical signal that varies depending on whether the object is accessed or not.

Referring to FIG. 2, a hovering object detecting method according to an embodiment of the present invention includes a parallel capacitor connected in parallel to a self-capacitor and a panel electrode capacitor formed between an object hovering a touch panel and electrodes of a touch panel, A first charge sharing step S200 of sharing a charge by connecting a parallel capacitor and a compensation capacitor in series, and a second charge sharing step S200 of connecting a parallel capacitor and a compensation capacitor in parallel, A shared second charge sharing step S300 and a step S400 of detecting an electrical signal provided by the parallel capacitor in a state where the parallel capacitor and the compensation capacitor are connected in parallel.

In this specification, an object to which a user can apply an input to a touch panel is defined as an " object ". Such an object refers to an object capable of touching or hovering the touch panel 100 such as a hand, a palm, a stylus, or the like to apply a touch input. However, this is not intended to limit the scope of the object but to describe the object, and the cheek, toe, etc., which can form the electrode and the self capacitance by hovering the touch panel, can also be objects.

Referring to FIG. 1, the touch panel 100 includes at least one electrode (not shown). The electrode functions as one electrode of the mutual capacitor Cs and the object O functions as the other electrode of the mutual capacitor Cs.

(C: capacitance, A: area of electrode, d: distance between electrodes)

Referring to Equation (1) for calculating the capacitance of the capacitor, the capacitance of the mutual capacitors decreases as the distance d between the object hobbering electrode and the electrode increases, and as the distance d decreases, The capacitance of the capacitor increases. Assuming an object having a diameter of about 10 mm and having a capacitance of about several fF of 10 fF or less when the distance between the electrode and the object is 1 cm or more, the conventional hovering object detection method and detection device has hundreds it is not easy to detect the mutual capacitance beyond the influence of the parasitic capacitor of about pF.

In the actual touch panel 100, there are various parasitic capacitances such as a parasitic capacitance formed between an electrode and a ground potential, a parasitic capacitance formed between adjacent electrodes, and the like. Hereinafter, the parasitic capacitance Cp refers to and refers to an equivalent parasitic capacitance including all the parasitic capacitances formed in the electrode forming the mutual capacitance with the hovering object.

In the self-capacitor Cs, the electrode of the touch panel forms one electrode of the capacitor, and the object forms another electrode of the capacitor. At this time, since the object is electrically connected to the ground potential, the self-capacitor Cs is connected in parallel with the parasitic capacitor Cp. The equivalent capacitance shown in the switch unit 200 is a capacitance of Cp + Cs formed by connecting the self capacitance Cs and the parasitic capacitance Cp in parallel.

The switch unit 200 includes a plurality of switches S1a, S1b, S2, S3, S4, S5 and a compensation capacitor Cc. The plurality of switches may be turned on / off by a signal provided by the controller 400 and may be implemented as a field effect transistor (FET) or a bipolar junction transistor (BJT). 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 parasitic capacitor Cp through two charge sharing processes as described later so that the influence of the self capacitance Cs can be easily detected.

The first supply voltage Vdd1 supplied to the switch unit 200 is a voltage formed by multiplying the second supply voltage Vdd2 provided to the detection circuit unit 300 or the like, And step-up the second supply voltage supplied to the inside of the chip. The first supply voltage Vdd1 may be supplied to the self-capacitor Cs to increase the amount of charge stored in the self-capacitor, thereby improving the detection performance of the object O to be hovered. The compensation capacitors (Cc) are connected to the n1 node and the n2 node, respectively. The compensating capacitor has a function of compensating the capacitance of the parasitic capacitor Cp as will be described later. The compensation capacitor Cc can be replaced with the capacitor array Cca shown in FIG. 7 (a), and even when the compensation capacitance is actively changed with respect to the parasitic capacitance change due to the environmental change, Can be improved.

Fig. 3 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 v _n from the self-capacitance Cs. The value of the self-capacitance Cs varies with the distance that the hovering object O is spaced from the electrode. The amplifier 310 receives and amplifies the varying electrical signal v _n to form an output signal v.

An amplifier 310 amplifies the input signal with a predetermined gain. The amplifier can be used in a hovering object detecting apparatus according to the present embodiment regardless of its form and configuration as long as it is an amplifier capable of receiving and amplifying an electrical 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 integrator 320 and an analog-to-digital converter (ADC) 330. The integrator accumulates the signal provided from the amplifier 310 of the detection circuit section. When the object is spaced apart from the electrode of the touch panel by a certain distance (for example, 10 cm), the self-capacitance value is formed to be 1 fF or less, and the voltage formed thereby may be difficult to distinguish from the noise level.

The output of the amplifier 310 can be integrated with the integrator 320 and converted to a digital signal and then compared with a noise level with an average power of zero to easily detect a signal by the hovering object. Then, the signal output from the integrator is provided to an analog-to-digital converter for converting the digital signal into a digital signal, and the analog signal is converted into a digital signal.

In one embodiment, the detection circuit section 300 operates by being provided with a second supply potential Vdd2 which is different from the switch section 200. [ The detection circuit section 300 may include an integrator and an analog-to-digital converter (ADC) or the like as in the embodiment to be described later. Therefore, when these are formed to operate at the first supply potential formed by multiplying the second supply potential, the die area required to implement the detection circuit section 300 increases. Therefore, the detection circuit section 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 the functional implementation.

The operation of the hovering object having the above-described configuration will be described with reference to FIGS. 2 and 4. FIG. 4 is an exemplary timing diagram showing the control signals provided by the control unit 400 to the switch unit 200. FIG. Referring to FIG. 4, the controller 400 controls the switch unit 200 to be in 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 switch unit 200 in the pre-charge phase P1 again after the output phase P4.

Referring to FIG. 4, the controller 400 controls each of the boundaries of each phase to prevent the charges charged in the respective capacitors from flowing out to the ground potential during the conduction and blocking of the switch. overlapping portions of the control signals.

The embodiment shown in FIG. 4 is an example in which the switches included in the switch unit 200 are implemented by NMOS (N type MOS) switches. Therefore, when the control terminal of each switch is provided with a high state signal, it is conducted, and when a low state signal is provided, 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.

FIGS. 5 and 6 are diagrams showing equivalent circuits for each phase in which the control unit 400 drives the switch unit 200. FIG. 5A is a diagram showing an equivalent circuit when the switch unit 200 is driven by the precharge phase P1. Referring to FIGS. 2, 4 and 5A, the switches S1a, S1b and S2 of the switch unit 200 are turned on in the step P1 (precharge phase) of FIG. 4, and the remaining switches are controlled to be turned off . 5 (a), and the equivalent capacitors Cp + Cs and the compensation capacitors Cc connected in parallel are connected in parallel in the precharge phase to the first And is charged to the supply potential Vdd1 (S100). In the equivalent circuit, the compensation capacitor Cc and the equivalent parallel capacitor Cp + Cc are provided with a first supply potential at each node, and each of the other nodes is connected to the ground potential. Therefore, the compensation capacitor Cc and the equivalent parallel capacitor Cp + Cc are connected in parallel.

5 (b) is a diagram showing an equivalent circuit when the switch section 200 is driven by the first charge sharing phase P2. Referring to FIGS. 2, 4 and 5 (b), in the first charge sharing phase P2, the switches S2 and S4 are turned on and the remaining switches are controlled to be turned off. In the equivalent circuit, the compensation capacitor Cc and the equivalent parallel capacitor Cp + Cc are connected in series between the first supply potential Vdd1 and the ground potential. Charges charged in the compensation capacitor Cc and the equivalent parallel capacitor Cp + Cc in the precharge phase P1 are distributed in the first charge sharing phase P2 (S200). The voltage Vn, which is charge-divided in the first charge sharing phase P2 and formed in the parallel capacitor Cp + Cc, is shown in Equation (2).

In one example, the second supply voltage Vdd2 provided to the amplifier is 2V, the first supply voltage Vddl is 9V, and the self-capacitor is negligible compared to Cp + Cs, which is the sum of the capacitance of the parasitic capacitor and the compensation capacitor Therefore, the above equation can be approximated as the right side.

The capacitance of the compensating capacitor should be 800 pF in order to form the parasitic capacitance (Cp) to 100 pF and Vn to 1 V, which is half of the wp2 supply voltage. However, a capacitance of 800 pF is a large capacitance value to be formed inside the chip, and it is uneconomical to form a capacitor having such a capacitance inside the chip.

6 (a) is a diagram showing an equivalent circuit when the switch unit 200 is driven by the second charge sharing phase P3. Referring to FIGS. 2, 4, and 6A, in the second charge sharing phase P3, the switches S2 and S5 are turned on and the remaining switches are turned off (S300). Charges charged in the compensation capacitor Cc and the equivalent parallel capacitor Cp + Cc 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) in Equation (3), the self-capacitor is negligibly smaller than Cp + Cs, which is the sum of the capacitance of the parasitic capacitor and the compensation capacitor, so that the above equation can be approximated as shown in Equation (2) below. A capacitor having a capacitance of 80 pF is required when the parasitic capacitance Cp, which is the same condition as in the first charge sharing phase, is 100 pF and Vn is to be 1 V which is half of the second supply voltage Vdd2 , Which is not a problem in forming inside the chip. In one embodiment, the capacitance of the compensation capacitor may be adjusted as described above to adjust the output voltage Vn of the switch unit 200 to a specific voltage value.

According to another embodiment, when the capacitance Cc of the compensation capacitor is matched with the parasitic capacitance in Equation (3), the influence of the parasitic capacitance Cp in the molecule can be canceled and the influence of the parasitic capacitance can be reduced. Therefore, the influence of the parasitic capacitance Cp at the output voltage Vn can be reduced and the influence by the self-capacitance formed by the hovering object O can be increased.

In the output phase P4, the control unit 400 maintains the turn-on state of the switch turned on in the second charge sharing phase, and turns off the switch while keeping the turn-off state, Vn to the detection circuit unit 300 (S400). The detection circuit unit 300 amplifies the provided signal to a predetermined gain G and provides it to a subsequent circuit to detect the hovering object O. [

In one embodiment, the detection circuitry 300 may further include an intergrator and an analog-to-digital converter (ADC) as shown in FIG. As described above, after the output of the amplifier is integrated by the integrator, the signal by the hovering object can be easily detected by comparing it with the noise level with the average power of zero. Then, information such as the position of the hovering object O is obtained by converting the signal output from the integrator into a digital signal, or the distance to the electrode is calculated.

Hereinafter, a case where the compensation capacitance is determined will be described with reference to FIG. FIG. 7A is a circuit diagram schematically showing a capacitance array used in the compensation capacitance determination apparatus according to the present embodiment, and FIG. 7B is a diagram showing a simulation result of the compensation capacitance determination apparatus.

Referring to FIG. 7A, the compensation capacitance determination apparatus according to the present embodiment includes a capacitor array CCa. The capacitor array CCa includes a plurality of capacitors C1, C2, ..., Cn and a plurality of switches SW1, SW2, ..., SWn, and the plurality of switches SW1, ..., and SWn). For example, the control unit 400 may be a control unit for controlling the conduction of the switches included in the switch unit 200.

The plurality of capacitors included in the capacitor array CCa may all have the same capacitance value and the number of capacitors connected to the first node n1 and the second node n2 may be controlled to control the capacitance of the capacitor array Cca And determines the equivalent capacitance. In other embodiments, they may have different capacitance values.

The control unit 400 controls the conduction of the plurality of switches SW1, SW2, ..., SWn to control the equivalent capacitance of the capacitor array CCa. For example, if the controller 400 controls only SW1 among the switches SW1, SW2, ..., SWn to conduct, the equivalent capacitance of the capacitor array CCa becomes C1, and the controller 400 controls the switches SW1, SW2, , And SWn switches, the equivalent capacitance of the capacitor array CCa becomes C1 + C2 + ... + Cn.

The capacitor array CCa may be replaced by a compensation capacitor CC, which is illustratively shown in FIG. 1, and the capacitance of the compensation capacitor (see FIG. 1Cc) may be determined by the equivalent capacitance of the capacitor array CCa.

Figure 7 (b) illustrates adjusting the equivalent capacitance value of the capacitor array CCa to determine the capacitance of the compensation capacitor. Referring to FIG. 7 (b), in one embodiment, the controller 400 implements an equivalent capacitance that can be implemented in the capacitor array CCa, and grasps the corresponding output voltage. If the output voltage is not within the desired output voltage range, the output voltage is determined after changing the equivalent capacitance value.

For example, the control unit can determine the output voltage while changing the equivalent capacitance of the capacitor array from maximum to minimum, and in another example, the control unit can grasp the output voltage while changing the equivalent capacitance of the capacitor array from maximum to minimum. In the embodiment shown in Fig. 7 (b), the target output voltage range is 1.8V, which is the second supply potential Vdd2 provided to the detection circuit section, and 0.9V, which is an intermediate level of the ground potential.

When the output voltage reaches a desired range (blue ellipse, Compenstation point) as the control unit 400 changes the equivalent capacitance of the capacitor array CCa, the control unit 400 supplies the equivalent capacitance to the compensation capacitor Cc, .

The hovering object detecting apparatus may be fixedly disposed in any one place, but may be changed in position such as a mobile phone, a tablet, or a notebook computer. The parasitic capacitance Cp can be increased or decreased by changing the temperature, humidity and the like of the surroundings even when the position is fixed as well as when the position is fixed. So that the detection performance for the hovering object can be reduced by changing the parasitic capacitance value. However, according to the present embodiment, there is provided an advantage that the detection performance of the hovering object can be improved by actively coping with the parasitic capacitance varying according to the environment and the position of the hovering object detecting apparatus.

In addition, the hovering object detecting apparatus according to the present embodiment can increase the influence of the self-capacitor formed between the electrode and the hovering object by providing a compensation capacitor for compensating the parasitic capacitance of the touch panel. This provides the advantage of being able to detect hovering objects 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.

100: touch panel 200: switch part
300: Amplification circuit part 400:
O: hovering object
S1 to S4: Each step of the hovering object detection method according to the present embodiment

Claims

A step of precharging a parallel capacitor and a compensation capacitor connected in parallel between an object for hobbling the touch panel and a self-capacitor and a parasitic capacitor formed between the electrodes of the touch panel,
A first charge sharing step of serially connecting the parallel capacitor and the compensation capacitor to share charge,
A second charge sharing step of connecting the parallel capacitor and the compensation capacitor in parallel to share charge; and
And outputting an electrical signal provided by the parallel capacitor while the parallel capacitor and the compensation capacitor are connected in parallel,
The first charge sharing step may include: providing the voltage to one end of the compensation capacitor, electrically connecting the other end of the compensation capacitor and one end of the parallel capacitor, and providing a ground potential to the other end of the parallel capacitor Of the hovering object.

delete

The method according to claim 1,
Wherein the second charge sharing step comprises:
Wherein one end of the compensation capacitor is provided with a ground voltage and the other end of the compensation capacitor is electrically connected to one end of the parallel capacitor and the ground voltage is provided to the other end of the parallel capacitor.

The method according to claim 1,
Wherein the capacitance value of the compensation capacitor is a value set such that the electrical signal provided by the parallel capacitor is at a desired level.

The method according to claim 1,
Wherein a capacitance value of the compensation capacitor changes according to a change of the parasitic capacitance.

The method according to claim 1,
The step of outputting the electrical signal includes:
Performing the electrical signal by providing the detection circuit portion,
Wherein the detection circuit unit receives the provided electrical signal, amplifies the received electrical signal to a predetermined gain, integrates the amplified signal, and then converts the integrated signal into a digital signal.

A touch panel having an electrode for constituting a self-capacitor together with a hovering object, the electrode having a parasitic capacitor;
A switching unit including a compensation capacitor for compensating the parasitic capacitor, the parallel capacitor being connected in parallel with the compensation capacitor connected in series, the parallel capacitor being connected in parallel with the self-capacitor and the parasitic capacitor;
And a detection circuit unit for detecting an electrical signal that varies depending on whether or not the hovering object is accessed,
The switching unit pre-charges the inter-parallel capacitor and the compensation capacitor, and performs a first charge sharing by connecting the parallel capacitor and the compensation capacitor in series, and connects the parallel capacitor and the compensation capacitor in parallel, And supplies the electrical signal from the self-capacitor to the detection circuit unit,
The switching unit includes:
A ground voltage is connected to one end of the compensation capacitor,
A second capacitor of the compensation capacitor is electrically connected to one end of the parallel capacitor,
And provides the ground voltage to the other end of the parallel capacitor to perform the second charge sharing.

8. The method of claim 7,
The switching unit includes:
And the precharging is performed by charging the parallel capacitor and the compensation capacitor to the supply potential, respectively.

8. The method of claim 7,
The switching unit includes:
A supply voltage is connected to one end of the compensation capacitor,
A second capacitor of the compensation capacitor is electrically connected to one end of the parallel capacitor,
And connecting the ground voltage to the other end of the parallel capacitor to perform the first charge sharing.

delete

8. The method of claim 7,
Wherein the compensation capacitor comprises:
And the potential of the parallel capacitor is controlled to be within a desired range upon the second charge sharing.

8. The method of claim 7,
Wherein a capacitance of the compensation capacitor changes in accordance with a capacitance change of the parasitic capacitor.

8. The method of claim 7,
The detection circuit section
An amplifier for amplifying and outputting the electrical signal provided from the self-capacitor, an integrator for integrating the amplified signal, and an analog-to-digital converter for converting the integrated signal to digital.

A switching matrix provided with a supply power supply potential and a first reference potential, the switching matrix comprising:
A plurality of switches;
A node electrically coupled to the input and output;
A first capacitor having one end connected to the node and the other end connected to a ground potential;
A second capacitor coupled to the node; And
And a control unit for controlling the plurality of switches,
The control unit includes:
A first phase for controlling the plurality of switches so that the supply power supply potential is provided to the first capacitor and the second capacitor, respectively,
A second phase for controlling the plurality of switches to connect the supply power supply potential, the second capacitor and the first capacitor in series, and
Controlling the plurality of switches in a third phase so that the first capacitor and the second capacitor are connected in parallel,
Wherein the switching matrix comprises:
Further comprising an output switch for connecting or disconnecting the output and an external circuit,
Wherein the control unit controls the fourth stage after the third phase to turn on the output switch while the first capacitor and the second capacitor are connected in parallel.

delete

15. The method of claim 14,
Wherein,
The output switch is turned off in the first to third phases,
And the first capacitor controls the transfer of an electrical signal to the output in the fourth phase.

A touch panel having an electrode for constituting a self-capacitor together with a hovering object, the electrode having a parasitic capacitor;
And a compensation capacitor for compensating the parasitic capacitor, the switching unit connecting the self-capacitor, the parasitic capacitor, and the compensation capacitor in parallel or in series,
A compensation circuit portion for determining a capacitance of the compensation capacitor, the compensation circuit portion comprising:
A capacitor array including a plurality of capacitors; and a controller for controlling the plurality of switches and the plurality of switches to control an equivalent capacitance of the capacitor array,
And a detection circuit unit for forming an electrical signal according to the change of the equivalent capacitance,
Wherein the control unit determines the capacitor having the equivalent capacitance as the compensation capacitor so that the electrical signal according to the change of the equivalent capacitance is within a predetermined range.

18. The method of claim 17,
Each capacitor of the plurality of capacitors
Wherein one end is connected to the first common node and the other end is connected to the second common node via the switch.

18. The method of claim 17,
Wherein the predetermined range includes a supply potential provided to the detection circuit section and a central level of the ground potential.

18. The method of claim 17,
Wherein the compensation capacitance determination device comprises:
Wherein the compensation capacitance determination unit determines the compensation capacitor again when the environment in which the compensation capacitance determination apparatus is located changes or a predetermined time elapses after the compensation capacitor determination.