The present invention relates to an acoustic sensor for measuring a sound wave propagating through a gas such as air or a fluid such as water and an elastic wave propagating through a solid medium. More particularly, the present invention relates to an acoustic sensor with a piezo-arrangement film capable of detecting frequencies in a broad band or amplifying a signal at a specific frequency by comparting a waveguide into an upper waveguide and a lower waveguide by means of a compartment diaphragm and arranging piezoelectric sensors on the compartment diaphragm in several forms.
The acoustic sensor according to the present invention can be utilized as a resonant acoustic sensor for amplifying a signal at a specific frequency by arranging piezoelectric sensors on a compartment diaphragm in the same form, or a broadband acoustic sensor for detecting frequencies in a broad band by arranging piezoelectric sensors in a different form.
A sound wave propagating through a gas or fluid and an elastic wave propagating through a solid medium are collectively called an “acoustic wave”.
Acoustic sensors for receiving a sound wave or an ultrasonic wave and generating an electric signal corresponding to vibration of the wave may be classified into a microphone, a subaqueous sound hydrophone (i.e., a subaqueous sound locator), an ultrasonic wave sensor, a sound emitting sensor, and the like, depending on a frequency band to be measured, a medium, and an object to be measured.
Also, acoustic sensors may be generally classified into resonant acoustic sensors and broadband acoustic sensors depending on measurable frequency bandwidths.
The resonant acoustic sensors have good signal reception sensibility and a high signal-to-noise ratio (SNR) but a narrow measurable frequency band. The broadband acoustic sensors have a relatively wider measurement frequency band but bad reception sensibility and a low signal-to-noise ratio.
An object of the present invention is to provide a resonant acoustic sensor or a broadband acoustic sensor using a piezoelectric material to address the aforementioned shortcomings of the conventional acoustic sensor, comprising a compartment diaphragm for comparting a waveguide into an upper waveguide and a lower waveguide, and piezoelectric sensors disposed on the compartment diaphragm in a various manner to amplify a signal at a specific frequency or detect several frequencies.
Another object of the present invention is to provide an acoustic sensor comprising a waveguide including a vibrating membrane for receiving the acoustic wave, an emitting membrane for emitting the acoustic wave, and a propagation medium filled therein for propagating the acoustic wave received by the vibrating membrane; a compartment diaphragm for comparting the waveguide into an upper waveguide and a lower waveguide; an omni-directional endpoint processing unit formed at an end of the waveguide for absorbing the acoustic wave received by the vibrating membrane; and a plurality of piezoelectric sensors formed on the compartment diaphragm for detecting the acoustic wave.
One aspect of the present invention provides an acoustic sensor with a piezo-arrangement film comprising: a waveguide including a vibrating membrane for receiving the acoustic wave, an emitting membrane for emitting the acoustic wave, and a propagation medium filled therein for propagating the acoustic wave received by the vibrating membrane; a compartment diaphragm for comparting the waveguide into an upper waveguide and a lower waveguide; an omni-directional endpoint processing unit formed at an end of the waveguide for absorbing the acoustic wave received by the vibrating membrane; and a plurality of piezoelectric sensors formed on the compartment diaphragm for detecting the acoustic wave.
As described above, the acoustic sensor according to the present invention can be utilized as a resonant acoustic sensor or a broadband acoustic sensor depending on the shape and arrangement of arranged electrodes. A combination of the resonant acoustic sensor and the broadband acoustic sensor can be utilized.
Furthermore, a small high-frequency acoustic sensor can be manufactured with the piezoelectric material.
Hereinafter, exemplary embodiments of the present invention will be described in detail. However, the present invention is not limited to the exemplary embodiments disclosed below, but can be implemented in various types. Therefore, the present exemplary embodiments are provided for complete disclosure of the present invention and to fully inform the scope of the present invention to those ordinarily skilled in the art.
Referring to
The acoustic sensor further comprises a compartment diaphragm 20 for comparting the waveguide 10 into an upper waveguide 11 and a lower waveguide 12; an omni-directional endpoint processing unit 50 formed at an end 15 of the waveguide 10 for absorbing the acoustic wave received by the vibrating membrane 13; and a plurality of piezoelectric sensors 30 formed on the compartment diaphragm 20 for detecting the acoustic wave.
As shown in
The acoustic sensor of
The omni-directional endpoint processing unit 50 for absorbing the acoustic wave may be provided at the end 15 opposite to the vibrating membrane 13 of the waveguide 10.
The omni-directional endpoint processing unit 50 serves to absorb the acoustic wave, as well known in the art. The omni-directional endpoint processing unit 50 suppresses generation of a reflection wave, thereby increasing the sensibility of the acoustic sensor.
The propagation medium filled in the waveguide 10, which is comparted into the upper waveguide 11 and the lower waveguide 12, propagates the acoustic wave from the vibrating membrane 13 to the emitting membrane 14. The propagation medium is a fluid medium. Alternatively, the propagation medium may be a solid medium.
The waveguide 10 may have a cross section that is circular, elliptic, triangular, rectangular, pentagonal, etc. depending on usage, as shown in
The waveguide 10 may have a plan profile as shown in
Specifically, the waveguide 10 may be formed in a rectangular shape as in
A piezoelectric material may be used for the above-configured acoustic sensor. As one example, the compartment diaphragm 20 for computing the waveguide 10 into the upper waveguide 11 and the lower waveguide 12 as shown in
Conductors 34 are connected to the electrodes 31 and 32 and to a signal processing unit (not shown), which processes electric signals generated by the piezoelectric sensors from the acoustic wave.
The signal processing unit for processing an electric signal generated by the acoustic sensor from the acoustic wave is well known in the art.
When the compartment diaphragm 20 is formed of a piezoelectric material, the upper electrode 31 of the piezoelectric sensor 30 is formed on an upper surface of the compartment diaphragm 20 and the lower electrode 32 on a lower surface. When the compartment diaphragm 20 is not formed of a piezoelectric material, the electrodes 31 and 32 are formed on the upper and lower surfaces of the piezoelectric material film 33, respectively.
The acoustic sensor can be utilized as a resonant acoustic sensor for amplifying a signal at a specific frequency or a broadband acoustic sensor for detecting frequencies in a broad band, depending on the shape and arrangement of a number of piezoelectric sensors 30 formed on the compartment diaphragm 20.
The acoustic sensor according to an embodiment of the present invention will now be described with reference to
Referring to
Referring to
Referring to
Referring to
Thus, the piezoelectric sensors 30 may have a different length l, width w and arrangement interval d depending on usage of the acoustic sensor.
The present invention provides the piezoelectric acoustic sensor that detects the acoustic wave with the piezoelectric sensors disposed on the plane and that can be utilized in various usages depending on the size and arrangement of the piezoelectric sensors.
While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
10-2006-0136408 | Dec 2006 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/KR2007/003639 | 7/27/2007 | WO | 00 | 2/4/2010 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2008/082053 | 7/10/2008 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
6029324 | Wixforth | Feb 2000 | A |
6236391 | Kent et al. | May 2001 | B1 |
6963647 | Krueger et al. | Nov 2005 | B1 |
20010033275 | Kent et al. | Oct 2001 | A1 |
20040060358 | Datskos | Apr 2004 | A1 |
20040107773 | Dunegan | Jun 2004 | A1 |
20090245028 | Donskoy et al. | Oct 2009 | A1 |
Number | Date | Country |
---|---|---|
09-243447 | Sep 1997 | JP |
2000-205940 | Jul 2000 | JP |
10-2005-0035869 | Apr 2005 | KR |
10-2005-0059075 | Jun 2005 | KR |
Number | Date | Country | |
---|---|---|---|
20100141090 A1 | Jun 2010 | US |