Touch detection device used in water handling equipment, and faucet apparatus including the same

Patent metadata

Field	Value
Publication number	US-9958418-B2
Application number	US-201615189262-A
Country	US
Kind code	B2
Filing date	Jun 22, 2016
Priority date	Jul 1, 2015
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A touch detection device capable of operation by a light touch, and of preventing false operations even when used in water handling equipment includes a sensing portion for sensing contact by a target object; a vibration excitation element attached to this sensing portion, a drive circuit for exciting vibration in the sensing portion, and a contact determining circuit for determining whether a target object is contacting a sensing portion based on vibration of the sensing portion after stopping the application of an AC voltage to the vibration excitation element by this drive circuit.

First claim

The invention claimed is:

1. A touch detection device used in water handling equipment, comprising:
a sensing portion for sensing contact with a target object;
a vibration excitation element attached to the sensing portion;
a drive circuit for exciting a vibration in the sensing portion by intermittently applying an AC voltage at a predetermined frequency to the vibration excitation element; and
a contact determination circuit configured to determine whether the target object has contacted the sensing portion based on vibration of the sensing portion after application of the AC voltage to the vibration excitation element by the drive circuit;
wherein the vibration excitation element comprises a piezo-electric element, and the contact determination circuit determines whether the target object has contacted the sensing portion based on an output signal from the vibration excitation element detected after stopping of the application of the AC voltage to the vibration excitation element;
wherein the vibration excitation element comprises an input terminal to which the AC voltage is applied by the drive circuit, the output signal from the vibration excitation element is obtained from the input terminal of the vibration excitation element, and the output of the drive circuit becomes high impedance after application of the AC voltage stops; and
wherein the contact determination circuit is configured to determine whether or not the target object has contacted the sensing portion based on a total of a plurality of voltage value acquired from the output signal of the vibration excitation element detected after the stopping of the application of the AC voltage by the drive circuit, and the contact determination circuit determines that the target object has made contact when the total is at or below a predetermined threshold value.

2. The touch detection device of claim 1 , further comprising a contact determination confirming circuit, wherein after the determination has first been made by the contact determination circuit that the target object has made contact, the contact determination confirming circuit performs a contact determination confirming operation to further reduce the possibility of false sensing.

3. The touch detection device of claim 2 , wherein once the contact by the target object has first been determined by the contact determination circuit, the contact determination confirming circuit performs the contact determination confirming operation in which the AC voltage at a confirming frequency different from the normal frequency of the AC voltage is applied, and the contact determination confirming circuit fixes the judgment of contact with the sensing portion when the contact of the target object is also determined by the contact determination circuit by applying the AC voltage at the confirming frequency.

4. A faucet apparatus for switching between water spouting and shut off by a touch operation, comprising:
the touch detection device of claim 1 ;
an operating portion including the sensing portion; and
an on-off valve for opening and closing based on a determination of contact by the target object with the sensing portion performed by the touch detection device.

5. A touch detection device used in water handling equipment, comprising:
a sensing portion for sensing contact with a target object;
a vibration excitation element attached to the sensing portion;
a drive circuit for exciting a vibration in the sensing portion by intermittently applying an AC voltage at a predetermined frequency to the vibration excitation element; and
a contact determination circuit configured to determine whether the target object has contacted the sensing portion based on vibration of the sensing portion after application of the AC voltage to the vibration excitation element by the drive circuit;
wherein the vibration excitation element comprises a piezo-electric element, and the contact determination circuit determines whether the target object has contacted the sensing portion based on an output signal from the vibration excitation element detected after stopping of the application of the AC voltage to the vibration excitation element;
wherein the vibration excitation element comprises an input terminal to which the AC voltage is applied by the drive circuit, the output signal from the vibration excitation element is obtained from the input terminal of the vibration excitation element, and the output of the drive circuit becomes high impedance after application of the AC voltage stops; and
wherein the contact determination circuit comprises an anomaly sensing circuit configured to prevent false sensing, and the anomaly sensing circuit senses an anomaly based on the output signal from the vibration excitation element detected during application of the AC voltage to the vibration excitation element.

6. The touch detection device of claim 5 , wherein the anomaly sensing circuit senses the anomaly when the amplitude of the output signal detected during application of the AC voltage is larger than the amplitude in normal operations, and the contact determination circuit does not determine the contact of the target object when the anomaly has been sensed.

7. The touch detection device of claim 5 , wherein during application of the AC voltage to the vibration excitation element, the anomaly sensing circuit is configured to sense an anomaly when fluctuations in the amplitude of the output signal exceed a predetermined level, and the contact determination circuit does not determine the contact of the target object when the anomaly has been sensed.

8. A touch detection device used in water handling equipment, comprising:
a sensing portion for sensing contact with a target object;
a vibration excitation element attached to the sensing portion;
a drive circuit for exciting a vibration in the sensing portion by intermittently applying an AC voltage at a predetermined frequency to the vibration excitation element;
a contact determination circuit configured to determine whether the target object has contacted the sensing portion based on vibration of the sensing portion after application of the AC voltage to the vibration excitation element by the drive circuit; and
a frequency adjustment circuit configured to adjust the frequency of the AC voltage applied to the vibration excitation element wherein the frequency adjustment circuit adjusts the frequency of the AC voltage to a resonant frequency of the sensing portion, to which the vibration excitation element is attached;
wherein the vibration excitation element comprises a piezo-electric element, and the contact determination circuit determines whether the target object has contacted the sensing portion based on an output signal from the vibration excitation element detected after stopping of the application of the AC voltage to the vibration excitation element;
wherein the vibration excitation element comprises an input terminal to which the AC voltage is applied by the drive circuit, the output signal from the vibration excitation element is obtained from the input terminal of the vibration excitation element, and the output of the drive circuit becomes high impedance after application of the AC voltage stops; and
wherein the frequency adjustment circuit applies the AC voltage for a predetermined period multiple times at different frequencies, and the frequency at which the amplitude of the output signal from the vibration excitation element is maximal following the stopping of the AC voltage application, is determined by the frequency adjustment circuit to be the mechanical resonant frequency of the sensing portion, to which the vibration excitation element is attached.

9. The touch detection

Assignees

• Toto Ltd

Inventors

• Kaneko Yoshiyuki

Classifications

• Y10T137/0318

  Processes · CPC title

• E03C1/055

  Electrical control devices, e.g. with push buttons, control panels or the like · CPC title

• H03K17/964

  Piezoelectric touch switches · CPC title

• Y10T137/9464

  Faucets and spouts · CPC title

• G01N29/12 Primary

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title