# US 10,309,131 B2 · Capacitive proximity sensor and door handle device comprising the capacitive proximity sensor

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- Number: US 10,309,131 B2
- Document ID: US10309131B2
- Status: Granted
- Kind: B2
- Application number: 15/473,950
- Filed: 2017-03-30
- Published: 2017-12-07
- Granted: 2019-06-04
- Earliest claimed: 2016-06-07
- Assignees: Tokyo Parts Industrial Co., Ltd.
- Applicants: Tokyo Parts Industrial Co., Ltd.
- Inventors: Mamoru Kubo
- Web page: https://patentgrep.com/patent/US10309131B2

## CPC

- G01D 5/24: by varying capacitance
- E05B 81/77: {comprising sensors detecting the presence of the hand of a user}
- E05B 85/10: Handles
- G01D 5/2405: {by varying dielectric}
- H03K 17/955: using a capacitive detector
- G07C 2209/65: using means for sensing the user's hand
- H03K 2217/960705: Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe
- H03K 2217/960755: Constructional details of capacitive touch and proximity switches
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- E05B: LOCKS; ACCESSORIES THEREFOR; HANDCUFFS
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE

## Abstract

The resonance frequency of an LCR resonance circuit is f1 and the determination voltage signal is V1, when an object is not in the proximity of a sensor electrode. The resonance frequency of the LCR resonance circuit is f2 and the determination voltage signal is V2, when a human body is in proximity of the sensor electrode 22. The resonance frequency of the LCR resonance circuit is f3 and the determination voltage signal is V3, when water is in the proximity of the sensor electrode. The LCR resonance circuit has the relationship f1>f2>f3. A control unit controls a high-frequency signal S0 so as to satisfy the relationship V2>V1>V3, and a human body or water being in the proximity of the sensor electrode is distinguished.

## Claims

### Claim 1

A capacitive proximity sensor comprising:
an oscillation means, which outputs a high-frequency signal;
a sensor circuit, having an LCR resonance circuit, including a sensor electrode, into which the high-frequency signal is input, and which outputs a determination voltage signal in accordance with the capacitance of the sensor electrode; and
a control unit, which detects the proximity of a human body to the sensor electrode, on the basis of the determination voltage signal;
wherein the resonance frequency of the LCR resonance circuit is f1 and the determination voltage signal is V1, when an object is not in the proximity of the sensor electrode,
wherein the resonance frequency of the LCR resonance circuit is f2 and the determination voltage signal is V2, when the human body is in the proximity of the sensor electrode, and
wherein the resonance frequency of the LCR resonance circuit is f3 and the determination voltage signal is V3, when water is in the proximity of the sensor electrode,
wherein f1>f2 >f3,
wherein the control unit controls the frequency of the high-frequency signal so as to satisfy the relationship V2>V1>V3 or V3>V1>V2,
wherein the control unit controls the frequency of the high-frequency signal so that V1 is substantially constant,
and wherein the human body or water in the proximity of the sensor electrode is distinguished.

### Claim 2

A door handle device comprising a door handle mounted to an outer panel of a vehicle door, and a capacitive proximity sensor, wherein:
the door handle has a space at the interior thereof, and
the capacitive proximity sensor is disposed within the space; and
the capacitive proximity sensor comprises:
an oscillation means, which outputs a high-frequency signal;
a sensor circuit, having an LCR resonance circuit, including a sensor electrode, into which the high-frequency signal is input, and which outputs a determination voltage signal in accordance with the capacitance of the sensor electrode; and
a control unit, which detects the proximity of a human body to the sensor electrode, on the basis of the determination voltage signal;
wherein the resonance frequency of the LCR resonance circuit is f1 and the determination voltage signal is V1, when an object is not in the proximity of the sensor electrode,
wherein the resonance frequency of the LCR resonance circuit is f2 and the determination voltage signal is V2, when the human body is in the proximity of the sensor electrode, and
wherein the resonance frequency of the LCR resonance circuit is f3, and the determination voltage signal is V3, when water is in the proximity of the sensor electrode,
wherein f1>f2>f3,
wherein the control unit controls the frequency of the high-frequency signal so as to satisfy the relationship V2>V1>V3 or V3>V1>V2,
wherein the control unit controls the frequency of the high-frequency signal so that V1 is substantially constant,
and wherein the human body or water in the proximity of the sensor electrode is distinguished.

### Claim 3 (depends on 2)

The door handle device according to claim 2, wherein:
the sensor electrode is formed on a board so that the sensor electrode faces the outer panel; and
a shield electrode is formed on a back face of the board, wherein the back face of the board does not have the sensor electrode formed thereon.

### Claim 4 (depends on 3)

The door handle device according to claim 3, wherein:
the surface of the door handle is electroconductive.

### Claim 5

A capacitive proximity sensor comprising:
a control unit which generates a control signal;
an oscillation means, which receives the control signal and which outputs a high-frequency signal controlled by the control signal;
an LCR resonance circuit which includes a sensor electrode that alters capacitance in response to either one or both of proximity or contact with an object, thereby altering capacitance of the LCR resonance circuit, the LCR resonance circuit receiving the high-frequency signal from the oscillation means and outputting in response a waveform; and
a smoothing circuit which receives the waveform from the LCR resonance circuit and generates in response a determination voltage signal in accordance with the capacitance of the sensor electrode;
wherein the control unit, the oscillation means, and the LCR resonance circuit are configured so that f1>f2>f3, where f1 is the resonance frequency of the LCR resonance circuit when said object is not in the proximity of the sensor electrode, where f2 is the resonance frequency of the LCR resonance circuit when a human body is the object in the proximity of the sensor electrode, and f3 is the resonance frequency of the LCR resonance circuit when water is the object in the proximity of the sensor electrode, and
so that either one of V2>V1>V3 or V3>V1>V2 is satisfied, where V1 is the voltage of the determination voltage signal when the object is not in the proximity of the sensor electrode, where V2 is the voltage of the determination voltage signal when the human body is in the proximity of the sensor electrode, and where V3 is the voltage of the determination voltage signal when water is in the proximity of the sensor electrode;
wherein the control unit analyzes the voltage determination signal to determine when the human body provides the capacitive proximity sensor input to the sensor electrode, to determine when water provides the capacitive proximity sensor input to the sensor electrode, and to determine when neither the human body nor water provides input to the capacitive proximity sensor at the sensor electrode;
wherein the control unit generates an output of the capacitive proximity sensor discerning human body detection from water detection, and discerning human body detection from the absence of each one of the human body and water at the sensor electrode.

### Claim 6 (depends on 5)

The capacitive proximity sensor of claim 5, wherein the control unit adjusts the control signal to control the frequency of the high-frequency signal so that V1 is substantially constant.

### Claim 7 (depends on 5)

The capacitive proximity sensor of claim 5 in combination with a door handle, the capacitive proximity sensor formed in the door handle mounted to an outer panel of a vehicle door, wherein the sensor electrode is formed on a board situated in the door handle, so that the sensor electrode is on an outer panel side of the board; and
a shield electrode is formed on a back face of the board opposite the outer panel side, wherein the back face of the board does not have the sensor electrode formed thereon.