KR102496360B1 - Inductive force sensor and mathod of operation thereof - Google Patents

Abstract

An inductive force sensor and an operating method thereof are disclosed. An inductive force sensor according to an embodiment of the present invention includes a reference resonance circuit and a first resonance circuit, and generates an inductive force sensor based on a displacement between a target and an inductive coil formed by an external force input along a Z-axis direction. and a decision circuit for acquiring information about a first resonant frequency due to a first inductance formed in the coil and a reference resonant frequency. A determination circuit determines the displacement of the target and the external force in the Z-axis direction based on the first resonant frequency and the reference resonant frequency.

Description

Inductive force sensor and its operating method {INDUCTIVE FORCE SENSOR AND MATHOD OF OPERATION THEREOF}

The present invention relates to a force sensor and its operating method, and specifically, it is formed on a target layer and a printed circuit board (PCB, Printed Circuit Board) or a flexible printed circuit board (FBCB) by an external force, or as a transparent electrode. An inductive force sensor that senses the degree of applied force using inductance that varies according to a change in distance between formed coils and an operating method thereof.

Recent touch recognition technology has made rapid progress, and in the 2D touch recognition technology that recognizes the touch position using coordinates on the X and Y axes, the strength of the touch (the force applied in the Z-axis direction) The 3D touch recognition function that enriches the user interface by detecting the size) has emerged.

3D touch of APPLE INC has introduced a technology that differentiates and recognizes the strength of a touch by combining a touch sensor and a pressure sensor. However, the method of combining the pressure sensor with the touch sensor increases hardware manufacturing cost, and since the sensitivity of the pressure sensor is not high, it is difficult to accurately recognize the user's touch intensity.

US 2017/0269754 "Dual Touch Sensor Architecture With XY-Position And Z-Force Sensing For Touch-On-Surface Button" by Texas Instruments Inc. combines a capacitive touch sensor and an inductive sensor, A position on the XY plane of is recognized by a capacitive touch sensor, and a touch force in the Z-axis direction at the touch position is recognized by an inductive sensor.

Another US published patent US 2018/0180450 "Inductive Touch Input" by Texas Instruments Inc. uses a plurality of inductive touch sensors to detect whether or not the touch and touch force are detected at different locations, and whether or not the touch is touched and the movement pattern of the touch force to recognize a touch scroll gesture.

Korean Patent Publication KR 10-2017-0007127 and US Patent Publication US 2017 as a prior art for detecting the user's intention to lock or unlock the car door by detecting the force applied to the car door by applying this 3D touch force recognition technology /0016255 "Device for Detecting a User's Intention to Lock or Unlock a Motor Vehicle Door", etc., as prior literature implementing an inductive force sensor by implementing a coil on a Flexible Printed Circuit Board (FPCB) Korean Registered Patent KR 10-1920440 "Self-inductive force sensor module for realizing 3D touch", Korean Patent Registered Patent KR 10-1954368 "Mutual inductive force sensor module for realizing 3D touch" have been introduced.

Prior literature for detecting touch force using an inductive sensor introduces a technology for recognizing touch force by selecting a new material or part such as placement of parts and elements, FPCB, etc. There are problems in that the precision of detecting the force is low and the hardware cost increases when the inductive sensor and other sensors are combined.

In addition, due to the recent rise of mobile devices and smart devices, there are various needs for user interfaces and user experiences. To meet these needs, a technology that distinguishes and recognizes touch forces for each microscopic area is required. To this end, a touch sensor/touch force sensor While arranging them densely, a technique for distinguishing and recognizing each sensor is also required, and it is difficult to meet this demand with the prior art.

US Patent Publication US 2017/0269754 "Dual Touch Sensor Architecture With XY-Position And Z-Force Sensing For Touch-On-Surface Button" (September 21, 2017) US Patent Publication US 2018/0180450 "Inductive Touch Input" (June 28, 2018) Korean Patent Publication No. KR 10-2017-0007127 "Device for detecting user's intention to lock or unlock a car door" (January 18, 2017) US Patent Publication US 2017/0016255 "Device for Detecting a User's Intention to Lock or Unlock a Motor Vehicle Door" (January 19, 2017) Korean Registered Patent KR 10-1920440 "Self-inductive force sensor module for realizing 3D touch" (November 14, 2018) Korean Registered Patent No. KR 10-1954368 "Mutual inductive force sensor module for realizing 3D touch" (February 26, 2019)

The prior art improves the sensitivity of a sensor through the arrangement of parts and elements, or the selection of parts or materials, or combines an inductive sensor with another sensor to sense a touch force and a touch position by sharing it, or uses a plurality of inductive sensors. These are technologies that implement and track sensing information of inductive sensors to recognize user gesture patterns.

In addition, the prior art varies the frequency of the input electrical signal applied to the resonance circuit, scans the magnitude of the output electrical signal formed in the resonance circuit in response to the input electrical signal, and calculates the frequency when it has the maximum magnitude as the resonance frequency. take the configuration Due to this, the prior art has an error as much as the resolution of the variable frequency of the input electrical signal, and is an indirect method of calculating the resonance frequency by detecting the magnitude of the electrical signal, and the accuracy is low, and since the frequency of the input electrical signal must be varied, measurement There is a problem that takes a lot of time.

In addition, since the prior art detects the magnitude of the electrical signal to calculate the resonant frequency and inductance, precise measurement is difficult, and therefore, it is difficult to quantitatively analyze the change in inductance only to determine whether the change in inductance exceeds a certain threshold. It does not provide sufficient accuracy.

The present invention was derived to solve the above problems in the prior art, and it is possible to reduce hardware cost by using only an inductive touch sensor and to accurately detect a touch position and touch force even when only an inductive touch sensor is used. It is an object of the present invention to provide an inductive force sensor and an operating method thereof.

In addition, the present invention senses the change in inductance with only a single measurement without frequency fluctuation or input of different frequency components, so that even in the case of a multi-channel inductive force sensor, the touch position and touch force are quickly detected and the user's intention is recognized. It is an object of the present invention to provide an inductive force sensor and an operating method thereof.

Since the present invention uses only an inductive touch sensor and does not require frequency fluctuation or input of different frequency components, power consumption required for sensing the touch position and touch force is reduced, and the multi-channel inductive force sensor An object of the present invention is to provide an inductive force sensor and an operating method thereof capable of significantly reducing power consumption even in the case of

An object of the present invention is to propose a circuit and operating method capable of effectively detecting a shift in a resonant frequency. In addition, since the inductive force sensor according to the present invention does not require a process of varying the frequency of an input electric signal, an object of the present invention is to shorten the sensing time of the touch position and touch force.

An object of the inductive force sensor according to the present invention is to reduce sensing time and reduce power consumption during sensing by simultaneously recognizing a touch position and a touch force using an inductive touch sensor without a capacitive sensor.

The present invention is a configuration derived to achieve the above object, and an inductive force sensor according to an embodiment of the present invention is exposed to an external force in the Z-axis direction, and is exposed to an external force in the Z-axis direction in the Z-axis direction. a first part elastically deformable along; an inductive coil formed on a substrate spaced apart from the first component; a first resonant circuit coupled to the inductive coil and having a first resonant frequency due to a first inductance formed in the inductive coil based on a displacement of the first component relative to the inductive coil; a first oscillator for applying a first AC signal to the first resonance circuit; a reference resonant circuit having the same impedance as a predetermined first state among possible states of the first resonant circuit; a reference oscillator having the same characteristics as the first oscillator and applying a reference AC signal to the reference resonance circuit; and receiving a first electrical signal formed in the first resonant circuit, receiving a reference electrical signal formed in the reference resonant circuit, the first resonant frequency of the first electrical signal and the reference resonance of the reference electrical signal. and a determination circuit for determining the displacement of the first component and the external force in the Z-axis direction based on a frequency.

The determination circuit of the inductive force sensor according to an embodiment of the present invention is configured to determine the reference resonant frequency of the reference electric signal formed in the reference resonant circuit by the influence of the reference AC signal applied to the reference resonant circuit and the first Detecting a difference between resonant frequencies, and based on the difference between the reference resonant frequency and the first resonant frequency, the degree to which the first resonant circuit deviates from the first state, and the first part moves relative to the inductive coil. Relative displacement and quantified sensing information about the external force in the Z-axis direction may be obtained.

The decision circuit of the inductive force sensor according to an embodiment of the present invention considers that the first resonant frequency has caused a significant change when the difference between the reference resonant frequency and the first resonant frequency is equal to or greater than a first threshold value, and the Z It can be determined that the external force in the axial direction is input.

The inductive coil of the inductive force sensor according to an embodiment of the present invention may be formed by overlapping a plurality of unit coil windings in a concentric structure.

The inductive coil of the inductive force sensor according to another embodiment of the present invention is composed of a set of a plurality of unit coil windings, and the plurality of unit coil windings are arranged to be spaced apart from each other as they move away from a specific position. can

At this time, the decision circuit of the inductive force sensor according to another embodiment of the present invention determines the inductive force sensor in an area covered by the inductive coil based on a change pattern of a difference between the reference resonant frequency and the first resonant frequency appearing in the time domain. Quantified detection information on the external force in the Z-axis direction and a user gesture intended by the external force in the Z-axis direction may be recognized.

A decision circuit of an inductive force sensor according to an embodiment of the present invention includes an operator that obtains a difference between the first resonant frequency and the reference resonant frequency; a low pass filter connected to the output terminal of the calculator to remove high frequency components; And connected to the output terminal of the low-pass filter to digitally count the frequency of the differential frequency component signal corresponding to the difference between the first resonant frequency and the reference resonant frequency (outputting a digitized value proportional to the frequency of the differential frequency component signal) a) time-to-digital converter (Time-to-Digital Converter).

The decision circuit of the inductive force sensor according to an embodiment of the present invention is based on a difference between the first resonant frequency and the reference resonant frequency in a state in which the first resonant circuit is externally forcibly adjusted to be in the first state. to perform the calibration process.

An inductive force sensor according to an embodiment of the present invention includes a plurality of individual regions exposed to an external force in the Z-axis direction and elastically deformable along the Z-axis direction by the external force in the Z-axis direction. 2 parts; a plurality of inductive coils formed on a substrate spaced apart from the second component, corresponding to each of the plurality of individual regions, and disposed to face each of the plurality of individual regions; A first coupled to a first one of the plurality of inductive coils and formed in the first inductive coil based on a first displacement of the discrete regions in the second component relative to the first inductive coil. a first channel resonant circuit having a first resonant frequency due to inductance; a first oscillator for applying a first AC signal to the first channel resonance circuit; A second inductive coil coupled to a second one of the plurality of inductive coils and formed in the second inductive coil based on a second displacement of the individual regions in the second component relative to the second inductive coil. a second channel resonant circuit having a second resonant frequency due to inductance; a second oscillator for applying a second AC signal to the second channel resonance circuit; a reference resonance circuit having the same impedance as a first predetermined state among states that the first channel resonance circuit may have and a second predetermined state among states that the second channel resonance circuit may have; a reference oscillator having the same characteristics as the first oscillator and the second oscillator and applying a reference AC signal to the reference resonance circuit; and receiving a first electrical signal formed in the first channel resonance circuit, a second electrical signal formed in the second channel resonance circuit, and a reference electrical signal formed in the reference resonance circuit; The first displacement, the second displacement, and the external force in the Z-axis direction are input based on the first resonant frequency, the second resonant frequency of the second electrical signal, and the reference resonant frequency of the reference electrical signal. and a determination circuit for determining the position and the external force.

The determination circuit of the inductive force sensor according to an embodiment of the present invention is configured to determine the reference resonant frequency of the reference electric signal formed in the reference resonant circuit by the influence of the reference AC signal applied to the reference resonant circuit and the first A difference between resonance frequencies is detected, and a degree to which the first channel resonance circuit deviates from the first state based on the difference between the reference resonance frequency and the first resonance frequency, the first state of the individual regions in the second part. Obtaining quantified sensing information about displacement and the external force in the Z-axis direction appearing in a first individual region corresponding to the first inductive coil, detecting a difference between the reference resonant frequency and the second resonant frequency, , the degree to which the second channel resonant circuit deviates from the second state based on the difference between the reference resonant frequency and the second resonant frequency, the second displacement of the individual regions in the second component, and the second inductor Quantified sensing information about the external force in the Z-axis direction appearing in the second individual region corresponding to the TV coil may be obtained.

The determination circuit of the inductive force sensor according to an embodiment of the present invention may include a first threshold at least one of a difference between the reference resonance frequency and the first resonance frequency or a difference between the reference resonance frequency and the second resonance frequency. If the value is greater than or equal to the value, it may be determined that the external force in the Z-axis direction has been input by considering that at least one of the first resonant frequency and the second resonant frequency has caused a significant change.

A decision circuit of an inductive force sensor according to an embodiment of the present invention includes a first change pattern of a difference between the reference resonant frequency and the first resonant frequency appearing in the time domain and the reference resonant frequency appearing in the time domain and the second resonant frequency. Quantified sensing information about the external force in the Z-axis direction in the first area covered by the first inductive coil based on the second change pattern of the difference in resonant frequency, and the first area covered by the second inductive coil. In area 2, it is possible to recognize quantified sensing information about the external force in the Z-axis direction and a user gesture intended by the external force in the Z-axis direction.

The determination circuit of the inductive force sensor according to an embodiment of the present invention may include the first inductor based on a difference between the reference resonance frequency and the first resonance frequency and a difference between the reference resonance frequency and the second resonance frequency. Quantified sensing information about the external force in the Z-axis direction in the first area covered by the active coil, and quantified sensing information about the external force in the Z-axis direction in the second area covered by the second inductive coil. It is possible to extract and determine whether the external force in the Z-axis direction is an input intended by the user.

A decision circuit of an inductive force sensor according to an embodiment of the present invention includes an operator that multiplies the first resonant frequency and the reference resonant frequency and multiplies the second resonant frequency and the reference resonant frequency; a low pass filter connected to the output terminal of the calculator to remove high frequency components; and digitally counting a frequency of a first differential frequency component signal corresponding to a difference between the first resonant frequency and the reference resonant frequency connected to an output terminal of the low-pass filter, and a difference between the second resonant frequency and the reference resonant frequency. It may include a time-to-digital converter that digitally counts the frequency of the second differential frequency component signal corresponding to .

In an operating method of an inductive force sensor according to an embodiment of the present invention, a first oscillator is coupled to the inductive coil and is formed in the inductive coil based on displacement of the first component with respect to the inductive coil. applying a first AC signal to a first resonant circuit having a first resonant frequency due to the first inductance; applying a reference AC signal to a reference resonant circuit in which the reference oscillator having the same characteristics as the first oscillator has the same impedance as a predetermined first state among possible states of the first resonator circuit; receiving, by a decision circuit, a first electrical signal formed in the first resonance circuit under the influence of the first AC signal; receiving, by the decision circuit, a reference electrical signal formed in the reference resonant circuit; and determining, by the determination circuit, the displacement of the first part and the external force in the Z-axis direction based on the first resonant frequency of the first electrical signal and the reference resonant frequency of the reference electrical signal.

At this time, the determining of the external force in the Z-axis direction by the determination circuit includes: detecting a difference between the reference resonant frequency and the first resonant frequency; and a degree of deviation of the first resonant circuit from the first state based on a difference between the reference resonant frequency and the first resonant frequency, a relative displacement of the first part moved with respect to the inductive coil, and the Z-axis. The method may include acquiring quantified sensing information about the external force in a direction.

In an operating method of an inductive force sensor according to an embodiment of the present invention, the determination circuit is based on a change pattern of a difference between the reference resonant frequency and the first resonant frequency appearing in the time domain, and the area covered by the inductive coil. The method may further include recognizing quantified detection information about the external force in the Z-axis direction and a user gesture intended by the external force in the Z-axis direction.

In an operating method of an inductive force sensor according to an embodiment of the present invention, a first oscillator is coupled to a first inductive coil among the plurality of inductive coils, and the second component for the first inductive coil applying a first AC signal to a first channel resonant circuit having a first resonant frequency due to a first inductance formed in the first inductive coil based on the first displacement of the individual regions; A second oscillator is coupled to a second inductive coil of the plurality of inductive coils and based on a second displacement of the discrete regions in the second component relative to the second inductive coil applying a second AC signal to a second channel resonant circuit having a second resonant frequency due to a second inductance formed in the; The reference oscillator having the same characteristics as the first oscillator and the second oscillator is configured to select a first state among states that the first channel resonance circuit can have and a state that the second channel resonance circuit can have. applying a reference AC signal to a reference resonant circuit having the same impedance as the second state; receiving, by a decision circuit, a first electrical signal formed in the first channel resonant circuit under the influence of the first AC signal; receiving, by a decision circuit, a second electrical signal formed in the second channel resonant circuit under the influence of the second AC signal; receiving, by the decision circuit, a reference electrical signal formed in the reference resonant circuit; and wherein the determination circuit determines the first displacement, the second displacement based on the first resonant frequency of the first electrical signal, the second resonant frequency of the second electrical signal, and the reference resonant frequency of the reference electrical signal. , and determining a position where the external force in the Z-axis direction is input and the external force.

At this time, the step of determining the input position and the external force in the Z-axis direction by the determination circuit includes: detecting a difference between the reference resonant frequency and the first resonant frequency; detecting a difference between the reference resonant frequency and the second resonant frequency; The degree of deviation of the first resonant circuit from the first state based on the difference between the reference resonant frequency and the first resonant frequency, the first displacement of the individual regions in the second part, and the first inductive coil obtaining quantified sensing information about the external force in the Z-axis direction appearing in a first individual region corresponding to ?; and a degree of deviation of the second resonant circuit from the second state based on a difference between the reference resonant frequency and the second resonant frequency, the second displacement of the individual regions in the second component, and the second inductive value. The method may further include acquiring quantified sensing information about the external force in the Z-axis direction appearing in the second individual region corresponding to the coil.

According to the present invention, since an inductive touch force sensor can be implemented using only an inductive sensor, hardware cost can be reduced.

According to the present invention, even when the inductive touch force sensor is implemented using only the inductive sensor, the touch position, touch force, touch pattern, and gesture can be precisely sensed. In this case, the touch position and/or the touch force may be simultaneously indicated by one output value.

According to the present invention, it is possible to detect a change in inductance with a single measurement without scanning frequency components, thereby reducing power consumption and reducing sensing time.

According to the present invention, since a change in inductance can be accurately detected by a single measurement for each sensor without scanning frequency components, even if an inductive sensor array or an inductive sensor matrix is formed and operated, it is relatively free from limitations in power consumption and sensing time. In addition, various touch patterns, touch gestures, and touch situations can be precisely determined using an array or matrix.

According to an embodiment of the present invention, a change in the time domain may be detected and a gesture may be recognized using a single-channel or single-coil inductive sensor.

According to an embodiment of the present invention, it is possible to verify that there is no error in the sensing result by combining sensing results simultaneously detected for a plurality of channels or coils. It is possible to verify whether the touch force derived from the sensing result is due to the user's intention or an error by considering the sensing result simultaneously detected for the plurality of coils and the positional relationship of areas covered by the coils.

Since the prior art detects the amplitude of a resonance signal or the amplitude of an analog AC signal, it can only detect whether or not the detected result exceeds a predetermined threshold value. However, since the present invention calculates the resonant frequency difference of the differential signal and digitally counts it, quantified sensing information can be obtained, and a change in touch force in time-space can be precisely detected using this.

1 is a diagram illustrating an inductive force sensor according to an embodiment of the present invention.
2 is a diagram illustrating an inductive force sensor according to an embodiment of the present invention.
3 is a diagram illustrating an inductive force sensor and an operating method thereof according to an embodiment of the present invention.
4 is a diagram illustrating an inductive force sensor and an operating method thereof according to an embodiment of the present invention.
5 is a diagram illustrating a coil structure of an inductive force sensor according to an embodiment of the present invention.
6 is a diagram illustrating a coil structure of an inductive force sensor according to an embodiment of the present invention.
7 is a diagram illustrating a circuit and operating method of an inductive force sensor according to an embodiment of the present invention.
8 is a diagram illustrating a circuit and operating method of an inductive force sensor according to an embodiment of the present invention.
9 is an operation flowchart illustrating an operating method of an inductive force sensor according to an embodiment of the present invention.
10 is an operation flowchart illustrating an operating method of an inductive force sensor according to an embodiment of the present invention.
11 is a diagram illustrating an inductive force sensor according to an embodiment of the present invention.
12 is a diagram illustrating an inductive force sensor according to an embodiment of the present invention.

In addition to the above objects, other objects and features of the present invention will become apparent through the description of the embodiments with reference to the accompanying drawings. A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, an inductive force sensor and an operating method thereof according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 10 attached.

1 is a diagram illustrating an inductive force sensor 100 according to an embodiment of the present invention. 1 shows an inductive force sensor 100 assuming a single button/channel/coil.

Referring to FIG. 1 , an inductive force sensor 100 according to an embodiment of the present invention is exposed to an external force 150 in the Z-axis direction, and is applied in the Z-axis direction by the external force 150 in the Z-axis direction. a first part 130 elastically deformable along; a target layer 140 disposed to be movable along the Z-axis direction based on deformation of the first part 130; an inductive coil 112 formed on a substrate 110 spaced apart from the target layer 140; and a spacer layer 160 supporting the first component 130 and separating the inductive force sensor 100 from other sensors or sensing channels.

The inductive force sensor 100 shown in FIG. 1 forms a single channel. Depending on embodiments, an array or matrix may be implemented by arranging a plurality of inductive force sensors 100 in parallel as shown in FIG. 1 .

When the first part 130 is elastically deformed by the external force 150 applied along the Z-axis direction, the target layer 140 may move along the Z-axis direction according to the degree of deformation of the first part 130. there is. At this time, the inductive coil 112 formed on the printed circuit board 110 and the target layer 140 are inductively coupled.

In this case, a material having an elastic restoring force, for example, foam, may be disposed between the target layer 140 and the inductive coil 112 . When an external force 150 is applied, the target layer 140 moves closer to the inductive coil 112, and accordingly, inductance formed in the inductive coil 112 coupled inductively to the target layer 140 changes.

When the external force 150 is removed, the target layer 140 returns to the position before deformation by the elastic restoring force of the foam. That is, a change in inductance appears only while the external force 150 is applied, and when this is detected, the external force 150 in the Z-axis direction can be sensed.

The distance at which the target layer 140 is separated from the inductive coil 112 in a first state in which the external force 150 is not applied is d0, and in the state in which the external force 150 is applied, the target layer 140 is inductively If the distance away from the coil 112 is d, the displacement Δd = |d-d0| is a cause of change in inductance formed in the inductive coil 112 inductively coupled to the target layer 140. Accordingly, when the change in inductance is detected, the displacement Δd can be detected and the magnitude of the external force 150 can be quantified.

In this specification, for convenience of description, one inductive coil 112 and a unit for sensing the external force 150 of the area covered by the inductive coil 112 will be referred to as a channel. The target layer 140 may be disposed for each channel separately from other channels as shown in FIG. 1 , or may be commonly disposed for a group consisting of a plurality of channels as shown in FIG. 2 described later. 1 shows an embodiment in which a target layer 140 is disposed for each individual channel and each channel is physically separated from other channels by a spacer layer 160 .

The target layer 140 may be a non-magnetic metal or a magnetic metal. The target layer 140 is preferably a conductive conductor so that an eddy current can be formed. Depending on whether the target layer 140 has magnetism, whether the inductance increases or decreases when the external force 150 is applied may be determined. A material optimized for variables such as displacement vs. inductance detection sensitivity based on the magnetic/non-magnetic properties of the target layer 140 and the hardware design of the channel may be selected as the target layer 140 .

The inductive coil 112 of the inductive force sensor 100 according to an embodiment of the present invention may be formed by overlapping a plurality of unit coil windings in a concentric structure.

The target layer 140 is moved in the Z-axis direction by the external force 150, but the target layer 140 may be implemented to maintain a state parallel to the inductive coil 112, but according to an embodiment of the present invention may move while forming a slight inclination with the inductive coil 112 according to a location on the XY plane where the external force 150 is concentrated in a state where the target layer 140 is not parallel to the inductive coil 112 . In this case, in the prior art, it becomes an error factor in measurement, making accurate touch force sensing a difficult factor. However, in the present invention, since the change in inductance can be precisely quantified based on differential detection of inductance, it is Of course, depending on the embodiment, the position on the XY plane where the external force 150 is concentrated may be precisely detected. This embodiment will be described later with reference to FIGS. 5 and 6 .

Since most wearable devices use mechanical buttons that require cutouts in an enclosure that forms a boundary with the outside, it is difficult to seal the device and the IP rating, which means dust and water resistance, may be lowered. In addition, mechanical buttons use moving parts, metallic contacts, and gaskets, which have long-term reliability problems, cause cost increases, and are resistant to environmental factors. have low problems.

If a cut out free enclosure can be implemented, a high IP rating can be implemented, and a wearable device with a higher IP rating can be used for various purposes that have not been utilized before. With gasket-less and no moving parts, wearable devices can be physically more robust, embedded in wearable elements such as gloves, for example. It can be used, and it can be used underwater.

In order to achieve such a high IP rating, there is an attempt to utilize an electromagnetic device that recognizes touch pressure instead of a mechanical button. As one of these attempts, there is a movement to use a capacitive proximity sensor, but the capacitive proximity sensor is affected by an electric field and whether or not the surroundings are energized, so it cannot be used underwater, and the range of use is limited. .

In place of the capacitive proximity sensor, an inductive touch sensor has been proposed that measures inductance by generating a change in a magnetic field in a manner of recognizing a touch pressure by measuring a change in impedance. The fact that the inductive sensor is less sensitive to external perturbation than the capacitive sensor is also a reason for the spread of the use of the inductive sensor.

A method of implementing an inductive force sensor using an inductive touch sensor has already been described in the aforementioned prior literature, for example, US Patent Publication US 2018/0180450 "Inductive Touch Input", US Patent Publication US 2017/0016255 "Device for Detecting a User's Intention to Lock or Unlock a Motor Vehicle Door", or Korean Registered Patent KR 10-1920440 "Self Inductive Force Sensor Module for Realizing 3D Touch".

On the other hand, it is not easy to increase the detection accuracy of an inductive sensor that must use a change in a magnetic field compared to a capacitive sensor that can precisely detect using an electrical signal. The inductive sensing technology of the prior literature is also mainly used for detecting a specific event to the extent of detecting whether or not it is above a certain threshold value rather than precise measurement.

The configuration of FIG. 1 and the preceding documents may be included as part of the configuration of the present invention, and the unique effects of the present invention will be achieved by combining with new configurations of the present invention to be mentioned later. In particular, recently combined with mobile devices, smart devices, virtual reality, and augmented reality, user interfaces aim to recognize precise touch forces, accurately recognize user gestures, and grasp user intentions. The present invention improves the inductive sensing of the prior art and proposes a technology that accurately measures and quantifies the touch force, the displacement of the target due to the touch force, and the change in inductance, thereby grasping the user's intention and accurately recognizing the user's gesture. do.

According to one embodiment of the present invention, when a separate coil is not disposed in the target layer 140, the eddy current of the inductive coil 112 and the target layer 140 respond in a self-inductive manner. Displacement of the target layer 140 may be measured.

According to another embodiment of the present invention, a mutual inductive coil (not shown) is disposed on the target layer 140, and the mutual inductive coil of the target layer 140 and the inductive coil 112 on the substrate 110 In response to this, the displacement of the target layer 140 can be measured in a mutually inductive manner.

2 is a diagram illustrating an inductive force sensor 200 according to an embodiment of the present invention.

Referring to FIG. 2 , the inductive force sensor 200 according to an embodiment of the present invention is exposed to an external force in the Z-axis direction, and is elastically deformed along the Z-axis direction by the external force in the Z-axis direction. a second part 230 comprising a possible plurality of discrete regions 232; a target layer 240 disposed to be movable along the Z-axis direction when at least one of the plurality of individual regions 232 is deformed by the second part 230; and formed on the substrate 210 spaced apart from the target layer 240, corresponding to each of the plurality of individual regions 232, and disposed opposite to each of the plurality of individual regions 232. A plurality of inductive coils 212 are included.

The second part 230 is made of an elastically deformable material, and the individual regions 232 may be made of the same material as the rest of the regions except for the individual regions 232 of the second part 230 . That is, since the second part 230 may surround the entire area of the inductive force sensor 200 shown in FIG. 2 with one outer shell, the IP rating of the inductive force sensor 200 may be increased. For example, assuming a smart watch in which individual regions 232 have independent numbers as shown in FIG. 2 , since the individual regions 232 exposed in the smart watch are surrounded by a single shell, excellent dustproof and waterproof performance is obtained. It is expected. Since the individual regions 232 are disposed corresponding to the holes of the spacer layer 260, when an external force is applied to one or more of the individual regions 232, the corresponding region is elastic based on the elasticity of the second part 230. Can be sexually transformed.

According to an embodiment of the present invention, the inductive force sensor 200 of FIG. 2 may be located on a bezel, side, or rear surface of a mobile device, and individual regions 232 are small in size so as not to be identified by a user. It can also be arranged densely with At this time, the inductive force sensor 200 may be used as a means for determining whether the user is holding the corresponding device or whether a predetermined user gesture has been input to an area of the inductive force sensor 200 of the corresponding device.

Unlike in FIG. 1 , in FIG. 2 , the target layer 240 is commonly disposed in a module including a plurality of individual regions 232 and inductive coils 212 . Assuming that the spacer layer 260 also has a weak elastic restoring force, the target layer 240 is distorted in the XYZ space depending on which region of the individual regions 232 a touch force is applied and is asymmetric to the inductive coils 212. will provide a positive displacement. For example, the distribution of inductance formed on the inductive coils 212 when the No. 1 button is pressed and when the No. 6 button is pressed will be different, and the inductive force sensor 200 ) can be stored by the controller. The inductive force sensor 200 may extract an input intended by the user by comparing an inductance distribution displayed in the plurality of inductive coils 212 when an external force is actually applied and an inductance distribution pattern stored in advance. .

In the prior art, it is not easy to simultaneously detect inductances of a plurality of channels. In the present invention, since the inductance of a plurality of channels can be simultaneously detected without a substantial time difference and quantified data can be obtained, the spatial distribution of the touch force within the area covered by the inductance force sensor 200 can be obtained, and the user's accurate intent can be discerned.

According to one embodiment of the present invention, when a separate coil is not disposed on the target layer 240, the eddy current of the inductive coil 212 and the target layer 240 respond in a self-inductive manner. Displacement of the target layer 240 may be measured.

According to another embodiment of the present invention, a mutual inductive coil (not shown) is disposed on the target layer 240, and the mutual inductive coil of the target layer 240 and the inductive coil 212 on the substrate 210 In response to this, the displacement of the target layer 240 can be measured using a mutual inductive method.

3 is a diagram illustrating an inductive force sensor 300 and an operating method thereof according to an embodiment of the present invention.

Referring to FIG. 3 , one module 310a is shown as a set of a plurality of coils 312 in the inductive force sensor 300 .

The user's touch force changes temporally and spatially within the area covered by the module 310a by tracking the spatial distribution on the XY plane of the inductance appearing in the plurality of coils 312 within the module 310a in the time domain. patterns can be traced.

The inductive force sensor 300 tracks the spatial distribution on the XY plane of the external force in the Z-axis direction recognized in the individual regions covered by each of the plurality of coils 312 in the time domain, so that the center of the external force is located on the XY plane It is possible to analyze the direction and speed of movement in the time domain on the image. According to this, the inductive force sensor 300 controls the pattern of the touch force applied by the user in the area covered by the inductive force sensor 300, for example, tapping, sliding/scrolling/swiping, or zooming in/zooming out. A user gesture, such as doing, may be recognized using an inductive sensing technique.

The inductive force sensor 300 combines X-axis movement information, in which the center position of the touch force moves along the X-axis direction, and Y-axis movement information, in which the center position of the touch force moves along the Y-axis direction, on the XY plane. Movement information on the XY plane in which the center position of the touch force moves may be derived. In another embodiment, the inductive force sensor 300 provides gesture information in which the center position of the touch force moves on the XY plane directly from the change pattern of the touch force obtained in individual regions covered by each of the plurality of coils 312. can also be obtained. In addition, since each channel information is obtained independently, the inductive force sensor 300 can recognize a user gesture without confusion even if a user gesture is input by multi-touch within the sensing area covered by the plurality of coils 312. there is.

4 is a diagram illustrating an inductive force sensor 400 and an operating method thereof according to an embodiment of the present invention.

Referring to FIG. 4 , one module 410a is shown as a set of a plurality of coils 412 in the inductive force sensor 400 .

For example, if the module 410a is an interface where numbers are assigned to individual regions and displayed on the outside, as shown in FIG. If this is measured evenly, it is not intended that the user touches a specific number area, but it may be measured that the device is held in the hand or pressure is applied by another factor from the outside, so that malfunction of the device can be prevented.

To this end, it is necessary to detect the inductance distribution pattern of the individual regions and the plurality of coils 412 included in the module 410a at substantially the same time. It achieves this by detecting the change and the touch force of the individual regions associated with each of the coils 412 . Matters related to this will be described later in the description of FIGS. 7 and 8 .

5 is a diagram illustrating a coil structure of an inductive force sensor 500 according to an embodiment of the present invention.

Referring to FIG. 5 , the inductive channel coil 512 of the inductive force sensor 500 according to an embodiment of the present invention is composed of a set of a plurality of unit coil windings, and the plurality of unit coil windings are located at specific positions. It may have a structure that is arranged so as to be spaced farther apart from each other as the distance increases.

The target layer 140 shown in FIG. 1 causes displacement in the Z-axis direction when an external force in the Z-axis direction is applied. At this time, the target layer 140 can necessarily maintain a state parallel to the inductive coil 512. no. Accordingly, the target layer 140 may be displaced in the Z-axis direction while being distorted in the XYZ space. In this case, the displacement of the target layer 140 may appear differently according to a position on the XY plane where the external force is concentrated within the channel region 514 covered by one inductive channel coil 512 . At this time, as shown in FIG. 5, if the coil structure of the inductive coil 512 is a structure in which the distance between the unit coil windings in the inductive coil 512 increases or decreases as the distance from the center of the inductive force sensor 500 increases, A change in inductance sensed by the inductive coil 512 will vary according to a position on the XY plane where the external force is concentrated within the channel region 514 . Therefore, by comparing a previously tested and stored inductance quantification pattern with an actually measured inductance quantification pattern, it is possible to identify a position on the XY plane where the external force is concentrated within the channel region 514 .

At this time, by identifying and tracking a position on the XY plane where the external force is concentrated within the channel region 514 in the time domain, a user gesture of tapping or sliding/scrolling/swiping can be recognized even in a single-channel inductive force sensor.

In FIG. 5, the structure of each inductive coil 512 is asymmetric, but when it is formed as a set of inductive coils 512 to form one module, the inductive force sensor 500 has symmetry so that the module has symmetry. ) can be implemented.

6 is a diagram illustrating a coil structure of an inductive force sensor 600 according to an embodiment of the present invention.

Referring to FIG. 6 , the inductive channel coil 612 of the inductive force sensor 600 according to an embodiment of the present invention is composed of a set of a plurality of unit coil windings, and the plurality of unit coil windings are located at specific positions. It may have a structure that is arranged so as to be spaced farther apart from each other as the distance increases.

At this time, the position on the XY plane where the external force is concentrated can be identified within the channel region 614 covered by one inductive channel coil 612, and when the position on the XY plane where the external force is concentrated is tracked in the time domain, a single The fact that a user gesture can be recognized even within the channel area 614 is as described above with reference to FIG. 5 .

In FIG. 6, the structure of each inductive coil 612 is asymmetrical, and when a module is formed by a set of inductive coils 612, the module maintains asymmetry but maintains regularity as an inductive force. A sensor 600 may be implemented.

7 is a diagram illustrating a circuit and operating method of an inductive force sensor 700 according to an embodiment of the present invention.

Referring to the inductive force sensor 100 of FIG. 1 and the circuit of FIG. 7 according to an embodiment of the present invention together, the inductive force sensors 100 and 700 are coupled to the inductive coils 112 and 712 and The first resonant frequency ω1 due to the first inductance formed in the inductive coil 112 or 712 based on the displacement of the target layer 140 or 740 relative to the inductive coil 112 or 712. 1 includes a resonant circuit 720.

At this time, the inductive force sensor 100 or 700 according to an embodiment of the present invention includes a first oscillator 722 for applying a first AC signal to the first resonance circuit 720; A reference resonance circuit (not shown in FIG. 7 ) having the same impedance as a first predetermined state (a state in which no external forces 150 and 750 are applied is preferred) among states that the first resonance circuit 720 may have. ); a reference oscillator (not shown in FIG. 7) having the same characteristics as the first oscillator 722 and applying a reference AC signal to the reference resonance circuit; and receiving a first electrical signal formed in the first resonant circuit 720, receiving a reference electrical signal formed in the reference resonant circuit, and measuring the first resonant frequency ω1 of the first electrical signal and the Displacement of the target layer (140, 740) based on the reference resonant frequency (ω_ref) of the reference electrical signal Δd = |d-d0| and a decision circuit 770 that determines the external forces 150 and 750 in the Z-axis direction.

The decision circuit 770 of the inductive force sensors 100 and 700 according to an embodiment of the present invention determines the reference electric signal formed in the reference resonance circuit under the influence of the reference AC signal applied to the reference resonance circuit. Detecting a difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, and based on the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, the first resonant circuit performs the The degree of deviation from the first state, the relative displacement of the target layer 140 or 740 relative to the inductive coil 112 or 712 Δd = |d-d0|, and the external force 150 in the Z-axis direction , 750) can be obtained.

The first resonant circuit 720 shown in FIG. 7 represents an equivalent circuit and does not necessarily include a lumped RLC element. For example, the capacitance C (716) and the resistor R (718) may be independent elements or may represent parasitic components. In addition, even when the first resonance circuit 720 is implemented using independent elements, the arrangement of elements does not necessarily follow FIG.

The decision circuit 770 of the inductive force sensor 100 or 700 according to an embodiment of the present invention may determine if the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1 is equal to or greater than a first threshold value. It may be determined that the external force 150 in the Z-axis direction is input by considering that the first resonant frequency ω1 has significantly changed. That is, when a change in the first resonant frequency ω1 is detected due to noise, unintentional motion, unintentional contact, or unintentional vibration, but is less than the first threshold value, the first resonant frequency ω1 shows a significant change. can be regarded as non-existent.

The decision circuit 770 of the inductive force sensors 100 and 700 according to an embodiment of the present invention is in a state forcibly adjusted from the outside so that the first resonance circuit 720 is in the first state (external A state in which no pressure 150 or 750 is applied is preferable. A calibration process may be performed based on the difference between the first resonant frequency ω1 and the reference resonant frequency ω_ref.

The decision circuit 770 may perform a calibration process. The decision circuit 770 may perform a calibration process in a state in which the external forces 150 and 750 are not applied. At this time, the first resonant circuit 720 or the reference resonant circuit may be adjusted so that the difference between the first resonant frequency ω1 and the reference resonant frequency ω_ref becomes zero through a calibration process. In addition, the difference between the first resonant frequency ω1 and the reference resonant frequency ω_ref detected in the first state in which the external forces 150 and 750 are not applied through the calibration process is stored in a separate memory or storage for future use. It can be processed as offset information in the process of inductive force sensing. After calibration, the difference between the first resonant frequency ω1 and the reference resonant frequency ω_ref is adjusted using means such as adjusting the value of the variable resistor R′ that can be added to the first resonant circuit 720. and can be executed.

In general, the inductive sensing technology known to date has been to sequentially input a plurality of frequency signals through variable frequency scan and then measure the change in impedance. This method is a prerequisite for accurately detecting and comparing the magnitude of the signal. there was However, it is very difficult to accurately detect the magnitudes of signals in spite of noise in a general inductive sensor.

In the present invention, instead of taking the amplitude of signals as the main detection target, the main detection target is the change of the resonance frequency, and also a means of applying an AC signal of the same frequency without adopting a method such as a variable frequency scan is sufficient for the intended purpose. can be achieved. Therefore, using this method, the present invention can quickly detect the change in inductance at a corresponding time and quantify it. A real-time change of the first resonant frequency ω1 may be detected regardless of the amplitude of the resonant signal by the method of FIG. 8 to be described later. In addition, since the first resonant frequency ω1 is not detected in an indirect way, but the value of the frequency is directly detected, it is easy to digitize using this, and the change in inductance and the change in touch force can be precisely measured using the digitized value. It has the advantage of being easily detectable. In addition, since there is no process such as variable frequency scan, the sensing process is fast and power consumption is low. Since the inductive sensing process for one coil and channel is fast and the sensing result is obtained as a digitized value, a change in inductance and a change in touch force can be detected substantially simultaneously even when a plurality of channels are implemented. If each channel and coil correspond to a position on the XY plane, the spatial change of the quickly obtained touch force on the XY plane can easily identify whether the touch force is due to the user's intention, error, or other causes. let it be In addition, by tracking the spatial change of the touch force on the XY plane in the time domain, it is possible to easily recognize a gesture by the user's intention.

Referring to the inductive force sensor 200 of FIG. 2 according to another embodiment of the present invention and the circuit of FIG. 7 together, the inductive force sensors 200 and 700 according to an embodiment of the present invention have the plurality of Combined with a first inductive coil of the inductive coils 212 and 712 and formed on the first inductive coil based on a first displacement of the target layer 240 and 740 relative to the first inductive coil a first channel resonant circuit 720 having a first resonant frequency ω1 due to the first inductance; a first oscillator 722 for applying a first AC signal to the first channel resonance circuit 720; It is combined with a second inductive coil among the plurality of inductive coils 212 and 712 and based on the second displacement of the target layer 240 and 740 relative to the second inductive coil, the second inductive coil a second channel resonant circuit (not shown) having a second resonant frequency (ω2) due to a second inductance formed in; a second oscillator (not shown) for applying a second AC signal to the second channel resonance circuit; a reference resonance circuit having the same impedance as a first predetermined state among possible states of the first channel resonance circuit 720 and a predetermined second state among possible states for the second channel resonance circuit; a reference oscillator having the same characteristics as the first oscillator 722 and the second oscillator and applying a reference AC signal to the reference resonance circuit; and receiving a first electrical signal formed in the first channel resonance circuit 720, a second electrical signal formed in the second channel resonance circuit, and a reference electrical signal formed in the reference resonance circuit, The first displacement, the second resonant frequency based on the first resonant frequency ω1 of the electrical signal, the second resonant frequency ω2 of the second electrical signal, and the reference resonant frequency ω_ref of the reference electrical signal. and a determination circuit 770 for determining displacement, and a position at which the external force 750 in the Z-axis direction is input and the external force 750 .

The decision circuit 770 of the inductive force sensors 200 and 700 according to an embodiment of the present invention determines the value of the reference electrical signal formed in the reference resonance circuit under the influence of the reference AC signal applied to the reference resonance circuit. Detecting a difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, and based on the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, the first channel resonant circuit ( 720) is out of the first state, the first displacement of the target 240, 740, and the external force 750 in the Z-axis direction appearing in a first individual region corresponding to the first inductive coil Obtaining quantified sensing information for , detecting a difference between the reference resonant frequency ω_ref and the second resonant frequency ω2, and a difference between the reference resonant frequency ω_ref and the second resonant frequency ω2 The degree of deviation of the second channel resonant circuit from the second state, the second displacement of the target 240, 740, and the Z axis appearing in a second individual region corresponding to the second inductive coil based on Quantified sensing information about the external force 750 in a direction may be obtained.

The decision circuit 770 of the inductive force sensors 200 and 700 according to an embodiment of the present invention determines the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, or the reference resonant frequency ω_ref. ) and the second resonant frequency (ω2), if at least one of the differences is greater than or equal to the first threshold value, at least one of the first resonant frequency (ω1) and the second resonant frequency (ω2) has caused a significant change. It can be determined that the external force 750 in the Z-axis direction is input.

Referring to the inductive force sensor 300 of FIG. 3 according to another embodiment of the present invention and the circuit of FIG. 7 together, the determination circuit of the inductive force sensors 300 and 700 according to an embodiment of the present invention ( 770) The first change pattern of the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1 appearing in the time domain and the reference resonant frequency ω_ref appearing in the time domain and the second resonant frequency ω2 ), the quantified sensing information about the external force 750 in the Z-axis direction in the first area covered by the first inductive coil, the second inductive coil covers In the second area, it is possible to recognize quantified sensing information about the external force 750 in the Z-axis direction and a user gesture intended by the external force 750 in the Z-axis direction.

At this time, even if a decision circuit is not assigned to each individual coil 312 of one module 310a and one decision circuit is assigned to one module 310a, the inductance distribution of the individual coils 312 can be substantially measured with a time difference. can be measured without

Referring to the inductive force sensor 400 of FIG. 4 according to another embodiment of the present invention and the circuit of FIG. 7 together, the determination circuit of the inductive force sensors 400 and 700 according to an embodiment of the present invention ( 770) Based on the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1 and the difference between the reference resonant frequency ω_ref and the second resonant frequency ω2, the first inductive resonant frequency Quantified sensing information about the external force 750 in the Z-axis direction in the first area covered by the coil, and the external force 750 in the Z-axis direction in the second area covered by the second inductive coil It is possible to extract quantified sensing information for the external force in the Z-axis direction and determine whether or not the external force in the Z-axis direction is an input intended by the user.

At this time, even if a decision circuit is not assigned to each individual coil 412 of one module 410a and one decision circuit is assigned to one module 410a, the inductance distribution of the individual coils 412 can be substantially measured with a time difference. can be measured without

Referring to the inductive force sensor 500 of FIG. 5 according to another embodiment of the present invention and the circuit of FIG. 7 together, the determination circuit of the inductive force sensors 500 and 700 according to an embodiment of the present invention ( 770) is the Z-axis in the channel region 514 covered by the inductive coil 512 based on the change pattern of the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1 appearing in the time domain. Quantified sensing information about the external force 750 in the direction and a user gesture intended by the external force 750 in the Z-axis direction may be recognized. That is, even within the single channel region 514, a change in the position of the external force 750 on the XY plane can be recognized, and a gesture intended by the user can be recognized by tracking the change in the position of the external force 750 on the XY plane in the time domain. there is.

8 is a diagram illustrating a circuit and operating method of an inductive force sensor 800 according to an embodiment of the present invention.

1 and 8 together, an inductive force sensor 100 or 800 according to an embodiment of the present invention includes a first resonance circuit 820, a first oscillator 822, and a reference resonance circuit 820a. , a reference oscillator 822a. Since the operations of the first resonance circuit 820, the first oscillator 822, and the reference resonance circuit 820a and reference oscillator 822a of FIG. 8 are similar to those described in the embodiments of FIG. 7, overlapping descriptions are made. is omitted.

The decision circuit 870 of the inductive force sensors 100 and 800 according to an embodiment of the present invention includes an operator circuit for obtaining a difference between the first resonant frequency ω1 and the reference resonant frequency ω_ref ( 872), a low pass filter 874 connected to the output terminal of the calculator circuit 872 to remove high frequency components, and a low pass filter 874 connected to the output terminal of the low pass filter 874 to obtain the first resonant frequency ( A time-to-digital converter (Time -to-Digital Converter) 876.

The calculator circuit 872 may immediately obtain a differential frequency component signal by using an arithmetic operation (addition, subtraction, multiplication) between the first electrical signal and the reference electrical signal. The time-to-digital converter 876 counts the number of pulses of a pulse signal having a differential frequency (or a frequency proportional to the differential frequency) during a certain time period, or pulses having a differential frequency (or a frequency proportional to the differential frequency) You can create a digital count value for the pulse width or period of a signal.

Depending on the embodiment, the decision circuit 870 may include a sampler and a comparator for differential frequency component signals. In this case, for smooth operation of the decision circuit 870, the sampler and the comparator are set sufficiently above the first threshold value. It can be designed by selecting an operating frequency that is large and sufficiently larger than the operating range of the resonant frequency component corresponding to the displacement to be sensed.

At this time, the reference resonant circuit 820a is managed to maintain the initialized setting by being blocked from external influences.

Referring to the inductive force sensor 200 of FIG. 2 and FIG. 8, which are another embodiment of the present invention, the decision circuit 870 of the inductive force sensors 200 and 800 according to an embodiment of the present invention An calculator circuit 872 calculating a difference between the first resonance frequency ω1 and the reference resonance frequency ω_ref, and a difference between the second resonance frequency ω2 and the reference resonance frequency ω_ref, and the calculator circuit 872 ) Is connected to the output terminal of the low pass filter (Low pass filter) 874 for removing high frequency components, and is connected to the output terminal of the low pass filter 874 to determine the first resonant frequency (ω1) and the reference resonant frequency ( The frequency of the first differential frequency component signal corresponding to the difference between ω_ref) is digitally counted, and the frequency of the second differential frequency component signal corresponding to the difference between the second resonant frequency ω2 and the reference resonant frequency ω_ref is digitally counted. Time-to-digital converter 876 for digital counting.

When a plurality of inductive coils 212 and channels are added, one resonant circuit may be added corresponding to each inductive coil 212 and channel. Even if a number of inductive coils 212 and channels are added, the reference resonant circuit 820a and the decision circuit 870 need not be added. The determination circuit 870 receives electrical signals received from each of the plurality of inductive coils 212 and channels by time multiplexing, and the difference between each channel resonant frequency of the received electrical signal of each channel and the reference resonant frequency (ω_ref) By detecting the difference, the inductance of each channel, the displacement generated by each channel, and the touch force generated by each channel can be detected. Although not shown, the inductance of each channel detected by the decision circuit 870, the displacement generated in each channel, and the touch force data generated in each channel are associated with channel identification information capable of identifying each channel and are associated with memory or storage. can be stored in

In the embodiments of the present invention, since the differential frequency component between the resonant frequency of each channel and the reference resonant frequency (ω_ref) can be obtained immediately in the decision circuits 770 and 870, the inductance of a plurality of channels substantially simultaneously without time delay, Displacement and touch force can be identified.

In embodiments of the present invention, the decision circuits 770 and 870 may detect resonant frequency information of each channel independently of the amplitudes of the electrical signal and the reference electrical signal of each channel (without detecting the amplitude). At this time, depending on the embodiment, the conventional technique of detecting the amplitude independently of the resonance frequency is applied in parallel, and two independently obtained sensing information (first sensing information based on detection of amplitude, resonance frequency independently of amplitude) The second detection information based on the detection of ) may be mutually cross-validated.

9 is an operation flowchart illustrating an operating method of an inductive force sensor according to an embodiment of the present invention.

The operating method of FIG. 9 may be executed in the inductive force sensors 100, 700, and 800 to which FIGS. 1, 7, and 8 are referred together.

In an operating method of the inductive force sensor 100, 700, 800 according to an embodiment of the present invention, the first oscillator 722, 822 is coupled to the inductive coil 112, 712, and the inductive coil 112 , 712, based on the displacement of the target 140, 740, 840, the first resonant circuit ( 720, 820) applying a first AC signal (S910); The reference oscillator 822a having the same characteristics as the first oscillators 722 and 822 has the same impedance as a predetermined first state among possible states of the first resonator circuit 720 and 820. Applying a reference AC signal to (820a) (S920); receiving a first electrical signal formed in the first resonant circuit 720 or 820 under the influence of the first AC signal by the decision circuit 770 or 870 (S930); receiving, by the decision circuits 770 and 870, a reference electrical signal formed in the reference resonant circuit 820a (S930); and the determination circuit (770, 870) determines the displacement of the target (140, 740, 840) based on the first resonant frequency (ω1) of the first electrical signal and the reference resonant frequency (ω_ref) of the reference electrical signal. and determining the external forces 150 and 750 in the Z-axis direction (S960).

At this time, the decision circuits 770 and 870 perform step S940 of detecting a difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, and based on the result of step S940, the first resonant frequency ωref is detected. 1 degree of deviation of the resonance circuits 720 and 820 from the first state, the relative displacement of the target 140, 740 and 840 relative to the inductive coil 112 and 712, and the A step of acquiring quantified sensing information about the external forces 150 and 750 (S960) may be performed.

At this time, the determination circuits 770 and 870 may perform a step S950 of determining whether a significant change is detected by determining whether the result of the step S940 exceeds a first threshold value.

In an operating method of the inductive force sensor 500, 700, 800 according to another embodiment of the present invention, the determination circuit 770, 870 determines the reference resonant frequency ω_ref and the first resonant frequency in the time domain. Quantified sensing information about the external force 750 in the Z-axis direction in the channel region 514 covered by the inductive coils 512 and 712 based on the change pattern of the difference of (ω1), and the Z-axis The method may further include recognizing a user gesture estimated to be intended by the user based on the external force 750 of the direction.

10 is an operation flowchart illustrating an operating method of an inductive force sensor according to an embodiment of the present invention.

The operating method of FIG. 10 may be executed in the inductive force sensors 200, 700, and 800 to which FIGS. 2, 7, and 8 are referred together.

In the method of operating the inductive force sensors 200, 700, and 800 according to an embodiment of the present invention, steps S910 to S930 of FIG. 9 are performed for the first channel, and in particular, the decision circuits 770 and 870 perform step S930. do Also, steps S910 to S930 of FIG. 9 are individually performed for the second channel.

A decision circuit (770, 870) determines the first displacement, the second resonant frequency of the second electrical signal, and the reference resonant frequency of the reference electrical signal. Steps (S1020 and S1040) of determining the second displacement, the location where the external force in the Z-axis direction is input, and the external force are performed.

At this time, the step of determining the input position and the external force in the Z-axis direction by the determination circuit includes: detecting a difference between the reference resonant frequency and the first resonant frequency (S1010); Detecting a difference between the reference resonant frequency and the second resonant frequency (S1030); A degree of deviation of the first resonant circuit from the first state based on a difference between the reference resonant frequency and the first resonant frequency, the first displacement of the target, and a first individual corresponding to the first inductive coil. obtaining quantified detection information about the external force in the Z-axis direction appearing in the region (S1020, S1060); and a degree of deviation of the second resonant circuit from the second state based on a difference between the reference resonant frequency and the second resonant frequency, a second displacement corresponding to the second displacement of the target, and the second inductive coil. The method may further include obtaining quantified sensing information about the external force in the Z-axis direction appearing in the individual area (S1040 and S1060).

Based on the results of steps S1020 and S1040, the decision circuits 770 and 870 determine whether the sensed touch force for the first channel and the second channel is an input intended by the user, and determines whether the input is an error or another input not intended by the user. It is determined whether or not the signal variation is due to a factor (S1050).

As a result of performing step S1050, if it is determined that the touch force is an input intended by the user, the decision circuits 770 and 870 determine the location where the touch force is input and the magnitude of the touch force with respect to the region including the first channel and the second channel. Digitize and quantify (S1060).

11 is a diagram illustrating an inductive force sensor 1100 according to an embodiment of the present invention. 11 shows an inductive force sensor 1100 assuming a single button/channel/coil.

FIG. 11 is an embodiment in which the first part 1140 of FIG. 11 performs the functions of the target layer 140 and the first part 130 in the embodiment of FIG. 1 . That is, in FIG. 11, a separate target layer does not exist, and the displacement in the Z-axis direction according to the deformation of the first part 1140 appears due to the inductive coupling between the inductive coil 1112 and the first part 1140. It can be detected through a change in inductance and a change in resonance frequency.

In FIG. 11 , the external force 1150 , the substrate 1110 , and the spacer layer 1160 are the same as the external force 150 , the substrate 110 , and the spacer layer 160 in FIG. 1 , so duplicate descriptions are omitted.

Since it is difficult to precisely measure the displacement of the first part 1140 in the Z-axis direction by the external force 1150 in conventional inductive sensing technologies, as part of an effort to increase the accuracy of measurement, the first part 1140 as shown in FIG. The target layer 140 is separately disposed under the part 130, and when the target layer 140 is displaced in the Z-axis direction based on the deformation of the first part 130 in the Z-axis direction, the displacement is detected. However, in the embodiment of the present invention, since the change in inductance is detected through the difference in the resonant frequency of the differential signal, it is easy to quantify and digitize the measurement value, and the displacement sensitivity is high. Therefore, as shown in FIG. 11 , it is possible to detect and quantify the external force 1150 in the Z-axis direction using only one first part 1140 . At this time, the first part 1140 and the inductive coil 1112 are connected to the inductive coil 1112 by inductive coupling between the first part 1140 and the inductive coil 1112 according to the distance in the Z-axis direction. The inductance of the resonant circuit to be changed. Therefore, only the displacement of the first part 1140 in the Z-axis direction can detect the change in inductance and the change in resonant frequency, and it is possible to detect and quantify the external force 1150 in the Z-axis direction. At this time, when the first component 1140 is deformed and an eddy current is induced in a portion closer to the inductive coil 1112, a change in combined inductance due to the displacement of the first component 1140 in the Z-axis direction is detected Accordingly, the first part 1140 may be implemented to be electrically conductive.

12 is a diagram illustrating an inductive force sensor 1200 according to an embodiment of the present invention.

FIG. 12 is an embodiment in which the second part 1230 of FIG. 12 performs the functions of the target layer 240 and the second part 230 in the embodiment of FIG. 2 . That is, in FIG. 12 , a separate target layer does not exist, and the displacement in the Z-axis direction according to the deformation of the individual regions 1232 in the second part 1230 is caused by the plurality of inductive coils 1212 and the second part. It can be detected through a change in inductance caused by inductive coupling between individual regions 1232 in 1230 and a change in resonance frequency.

In FIG. 12 , since the substrate 1210 and the spacer layer 1260 are the same as the substrate 210 and the spacer layer 260 in FIG. 2 , overlapping descriptions are omitted.

Conventional inductive sensing technologies are difficult to precisely measure the displacement in the Z-axis direction of each of the individual regions 1232 in the second part 1230 due to external force. As part of an effort to increase the accuracy of measurement, FIG. As in, if the target layer 240 is separately disposed under the second part 230 and the target layer 240 is displaced in the Z-axis direction based on the deformation of the second part 230 in the Z-axis direction, displacement is detected. However, in the embodiment of the present invention, since the change in inductance is detected through the difference in the resonant frequency of the differential signal, it is easy to quantify and digitize the measurement value, and the displacement sensitivity is high. Therefore, as shown in FIG. 12, the target layer is not disposed, and each of the individual regions 1232 is formed by inductive coupling between each of the individual regions 1232 in the second part 1230 and the plurality of inductive coils 1212. Displacement can be detected and quantified.

When an external force is applied to the first individual region of the individual regions 1232 and the first individual region is deformed and the first individual region is displaced in the Z-axis direction, the first individual region among the plurality of inductive coils 1212 Whether or not an external force is applied to the first discrete region and the magnitude of the external force may be determined based on a change in inductance sensed by the first inductive coil facing the first inductive coil. Displacement in the Z-axis direction of the first individual region (deformation of the first individual region with respect to the first inductive coil and displacement in the Z-axis direction) of the first individual region by inductive coupling between the first inductive coil and the first individual region The inductance of the first resonant circuit to which the inductive coil is connected is affected. Based on the changed inductance of the first resonant circuit, the change in the first resonant frequency ω1 of the first resonant circuit is determined by the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1 in the determination circuit 770 or 870. Based on the difference between the reference resonant frequency ω_ref and the first resonant frequency ω1, the change in the first resonant frequency ω1 is quantified. The change of the quantified first resonant frequency ω1 may be digitized and stored in a separate memory or storage.

At this time, inductance of a resonant circuit connected to each of the inductive coils 1212 is varied by inductive coupling between the individual regions 1232 in the second part 1230 and the opposing inductive coils 1212 . Accordingly, a change in inductance and a change in resonant frequency are detected only by the displacement of the individual regions 1232 in the Z-axis direction, and it is possible to detect and quantify an external force in the Z-axis direction. At this time, when an eddy current is induced in a part of the individual regions 1232 in the second part 1230 where the distance to the inductive coils 1212 becomes closer due to an external force, synthesis by displacement in the Z-axis direction A change in inductance is detected. If the individual regions 1232 are implemented so that the eddy current is easily induced, the change in the combined inductance is better displayed, so that the sensitivity of the sensor can be improved. At this time, in order to easily induce eddy current in the individual regions 1232, the individual regions 1232 within the second part 1230 should have higher electrical conductivity than the rest of the regions within the second part 1230. can For example, a thin metal film such as aluminum, which is nonmagnetic and electrically conductive, may be disposed on the individual regions 1232 to increase electrical conductivity of the individual regions 1232, and displacement of the individual regions 1232 in the Z-axis direction sensitivity can be improved.

A method of operating a circuit according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the medium may be those specially designed and configured for the present invention or those known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to act as one or more software modules to perform the operations of the present invention, and vice versa.

However, the present invention is not limited or limited by the examples. Like reference numerals in each figure indicate like elements. Length, height, size, width, etc. introduced in the embodiments and drawings of the present invention may be exaggerated for better understanding.

As described above, the present invention has been described by specific details such as specific components and limited embodiments and drawings, but these are provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , Those skilled in the art in the field to which the present invention belongs can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and it will be said that not only the claims to be described later, but also all modifications equivalent or equivalent to these claims belong to the scope of the present invention. .

100, 200, 300, 400, 500, 600, 700, 800, 1100, 1200: Inductive force sensors
110, 210, 1110, 1210: PCB
310a, 410a: one module consisting of a set of a plurality of coils
112, 212, 312, 412, 1112, 1212: inductive coil
512, 612: channel coil
514, 614: channel area
130, 230: deformable parts
232, 1232: individual area
140, 240: target layer
150, 750: force from outside (external force)
452: range in which external force is input
160, 260, 1160, 1260: spacer layer
770, 870: decision circuit

Claims (11)

a first part disposed on a substrate, exposed to an external force in the Z-axis direction, and elastically deformable along the Z-axis direction by the external force in the Z-axis direction;
an inductive coil formed on the substrate corresponding to the first component;
a first resonant circuit electrically connected to the inductive coil; and
a signal processing circuit for receiving a first electrical signal formed on the first resonance circuit and the inductive coil and receiving a reference electrical signal formed in a reference resonance circuit;
including,
The signal processing circuit performs signal processing on the first electrical signal and the reference electrical signal to obtain a sensing signal corresponding to a difference between a first resonant frequency of the first electrical signal and a reference resonant frequency of the reference electrical signal. create,
Relative displacement of the upper surface of the first part moved in the Z-axis direction with respect to the inductive coil by the detection signal and quantified detection information about the external force in the Z-axis direction are displayed,
The signal processing circuit converts the detection signal in the time domain such that a change pattern of the quantified detection information for the external force in the Z-axis direction in a region covered by the inductive coil is represented by a change pattern in the time domain of the detection signal. Inductive force sensor outputting on phase. According to claim 1,
If the magnitude of the detection signal is greater than or equal to a first threshold value, it is considered that the first resonant frequency has undergone a significant change and it is determined that the external force in the Z-axis direction is input.
Inductive force sensor. According to claim 1,
a target disposed on the top side of the first part;
Including more,
Based on whether or not the target is magnetic, it is determined whether the direction of the first inductance change appearing in the first resonant circuit is due to an external force in the Z-axis direction, and the direction of the first inductance change is in the Z-axis direction. An inductive force sensor in which a polarity of a first threshold is determined to be due to an external force. a first part disposed on a substrate, exposed to an external force in the Z-axis direction, and elastically deformable along the Z-axis direction by the external force in the Z-axis direction;
an inductive coil formed on the substrate corresponding to the first component;
a first resonant circuit electrically connected to the inductive coil; and
a signal processing circuit for receiving a first electrical signal formed on the first resonance circuit and the inductive coil and receiving a reference electrical signal formed in a reference resonance circuit;
including,
The signal processing circuit performs signal processing on the first electrical signal and the reference electrical signal to obtain a sensing signal corresponding to a difference between a first resonant frequency of the first electrical signal and a reference resonant frequency of the reference electrical signal. create,
Relative displacement in which the upper surface of the first part moves with respect to the inductive coil and quantified sensing information about the external force in the Z-axis direction are indicated by the sensing signal,
The inductive force sensor has a structure in which the inductive coil is formed of a set of a plurality of unit coil windings, and the plurality of unit coil windings are arranged to be spaced apart from each other as the distance from a specific position increases. According to claim 4,
Based on the change pattern of the sense information appearing in the time domain, the change pattern of the quantified sense information for the external force in the Z-axis direction in the area covered by the inductive coil and the intention by the external force in the Z-axis direction An inductive force sensor that recognizes user gestures. Board;
a first inductive coil on the substrate;
a second inductive coil on the substrate;
a first individual region of the upper surface of the part corresponding to the first inductive coil, deformable by an external force in the Z-axis direction, and exposed to the external force in the Z-axis direction;
a second individual region of the upper side corresponding to the second inductive coil as another part of the upper side, deformable by an external force in the Z-axis direction, and exposed to an external force in the Z-axis direction;
A first electrical signal connected to the first inductive coil and having a first resonant frequency due to a first inductance formed in the first inductive coil based on a first displacement of the first discrete region is formed. 1-channel resonant circuit;
A second electrical signal connected to the second inductive coil and having a second resonant frequency due to a second inductance formed in the second inductive coil based on a second displacement of the second individual region is formed. 2-channel resonant circuit; and
a signal processing circuit receiving the first electrical signal and the second electrical signal and receiving a reference electrical signal formed in a reference resonant circuit;
including,
The signal processing circuit generates a first channel detection signal corresponding to a difference between the first resonant frequency and a reference resonant frequency of the reference electrical signal by performing signal processing on the first electrical signal and the reference electrical signal; ,
The signal processing circuit generates a second channel detection signal corresponding to a difference between the second resonant frequency and the reference resonant frequency by performing signal processing on the second electrical signal and the reference electrical signal;
The first position, the second displacement, and the location where the external force in the Z-axis direction is input and quantified detection information about the external force are indicated by the first channel detection signal and the second channel detection signal. active force sensor. According to claim 6,
Based on the first change pattern of the first channel detection signal appearing in the time domain and the second change pattern of the second channel detection signal appearing in the time domain, the external force in the Z-axis direction is determined in the first individual region. An inductive device for recognizing a change pattern of quantified sensing information, a change pattern of quantified sensing information for the external force in the Z-axis direction in the second individual region, and a user gesture intended by the external force in the Z-axis direction. force sensor. According to claim 6,
Based on the first channel detection signal and the second channel detection signal, the quantified detection information on the external force in the Z-axis direction in the first individual region and the Z-axis direction in the second individual region An inductive force sensor that extracts quantified sensing information about the external force and determines whether the external force in the Z-axis direction is an input intended by a user. The signal processing circuit is based on the displacement of the upper surface exposed to the external force in the Z-axis direction of the first part corresponding to the inductive coil and elastically deformable along the Z-axis direction by the external force in the Z-axis direction. receiving a first electrical signal having a first resonant frequency due to a first inductance formed in the inductive coil from a first resonant circuit connected to the inductive coil;
receiving, by the signal processing circuit, a reference electrical signal having a reference resonant frequency from a reference resonant circuit;
generating, by the signal processing circuit, a detection signal corresponding to a difference between the first resonant frequency and the reference resonant frequency by performing signal processing on the first electrical signal and the reference electrical signal; and
outputting, by the signal processing circuit, the detection signal in a time domain;
including,
Relative displacement of the upper surface of the first part moved in the Z-axis direction with respect to the inductive coil by the detection signal and quantified detection information about the external force in the Z-axis direction are displayed,
A method of operating an inductive force sensor in which a change pattern of quantified sensing information for the external force in the Z-axis direction is represented in a region covered by the inductive coil by a change pattern of the sensing signal in the time domain. The signal processing circuit is based on the displacement of the upper surface exposed to the external force in the Z-axis direction of the first part corresponding to the inductive coil and elastically deformable along the Z-axis direction by the external force in the Z-axis direction. receiving a first electrical signal having a first resonant frequency due to a first inductance formed in the inductive coil from a first resonant circuit connected to the inductive coil;
receiving, by the signal processing circuit, a reference electrical signal having a reference resonant frequency from a reference resonant circuit; and
generating, by the signal processing circuit, a detection signal corresponding to a difference between the first resonant frequency and the reference resonant frequency by performing signal processing on the first electrical signal and the reference electrical signal;
including,
Relative displacement in which the upper surface of the first part moves with respect to the inductive coil and quantified sensing information about the external force in the Z-axis direction are indicated by the sensing signal,
Based on the change pattern of the sense information appearing in the time domain, the change pattern of the quantified sense information for the external force in the Z-axis direction in the area covered by the inductive coil and the intention by the external force in the Z-axis direction recognizing a user's gesture;
Method of operating an inductive force sensor further comprising a. A signal processing circuit, as a part of the upper side of the component, corresponds to the first inductive coil, is deformable by an external force in the Z-axis direction, and is exposed to the external force in the Z-axis direction. receiving a first electrical signal having a first resonant frequency due to a first inductance formed in the first inductive coil based on a first displacement from a first resonant circuit connected to the first inductive coil;
The signal processing circuit corresponds to a second inductive coil as another part of the upper side surface, is deformable by the external force in the Z-axis direction, and is exposed to the external force in the Z-axis direction. A second electrical signal having a second resonant frequency resulting from the second inductance formed in the second inductive coil based on the second displacement of the individual region is received from a second resonant circuit connected to the second inductive coil. doing;
receiving, by the signal processing circuit, a reference electrical signal having a reference resonant frequency from a reference resonant circuit;
generating, by the signal processing circuit, a first channel detection signal corresponding to a difference between the first resonant frequency and the reference resonant frequency by performing signal processing on the first electrical signal and the reference electrical signal; and
generating, by the signal processing circuit, a second channel detection signal corresponding to a difference between the second resonant frequency and the reference resonant frequency by performing signal processing on the second electrical signal and the reference electrical signal;
including,
The first position, the second displacement, and the location where the external force in the Z-axis direction is input and quantified detection information about the external force are indicated by the first channel detection signal and the second channel detection signal. Operation method of the active force sensor.

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