JP2013157740A - Parametric speaker and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parametric speaker which prevents variations in orientations of ultrasonic waves and phase shift and does not block vibrations of an ultrasonic wave sounder, and to provide a manufacturing method of the parametric speaker.SOLUTION: A parametric speaker emits ultrasonic waves from multiple oscillation sources and includes: a flat plate like substrate 110 where wiring patterns 113 and 114 are provided; support members 121 made of a rubber material and provided on the substrate; a piezoelectric vibrator 124 supported by the support members 121 at vibration nodes so that the height from the substrate becomes uniform; and a resonator 127 provided on the piezoelectric vibrator 124 and generating the ultrasonic waves. This structure prevents variations of orientations of the ultrasonic waves and phase shift. Further, the structure avoids blocking vibrations of the piezoelectric vibrator 124 and prevents the vibrations from being transmitted to the substrate 110. As a result, the performance of the parametric speaker 110 is improved.

Description

  The present invention relates to a parametric speaker that emits ultrasonic waves from a plurality of oscillation sources and a method for manufacturing the same.

  The ultrasonic sounding body includes a piezoelectric vibrator in which a metal plate and a piezoelectric element are bonded. The ultrasonic sounding body vibrates by applying an AC voltage having a resonance frequency unique to the piezoelectric vibrator to the piezoelectric vibrator, and emits a sound having the same frequency as the resonance frequency. The ultrasonic sounding body is called an ultrasonic sounding body because the resonance frequency is configured to be included in the ultrasonic band (exceeding 20 kHz).

  Further, the ultrasonic sounding body can increase the sound pressure by attaching a conical cylinder-shaped (including parabolic and funnel-shaped) resonator made of aluminum or an aluminum alloy to the piezoelectric vibrator, and can increase the sound pressure from the front 60 to It can have a directivity of 70 degrees. The ultrasonic sounding body is fixed by adhering a node that does not move in the bending vibration of the piezoelectric vibrator to the terminal block with a silicon adhesive or the like so as to prevent the vibration as much as possible. Note that the ultrasonic sounding body has the same structure as the ultrasonic sensor, the ultrasonic sensor transmits and receives ultrasonic waves, and the ultrasonic sounding body only transmits ultrasonic waves.

  With respect to ultrasonic sensors, research has been conducted to prevent variations in reverberation characteristics and changes over time. For example, in the ultrasonic sensor described in Patent Document 1, the piezoelectric vibrator is joined to an annular joint protruding through a resin-molded elastic body, thereby preventing reverberation characteristics from varying and changes with time. .

  In the ultrasonic sensor described in Patent Document 1, the terminal block and the annular joint are made of synthetic resin. If the piezoelectric vibrator comes into contact with the annular joint, an abnormal noise may be generated, so the piezoelectric vibrator is joined to the annular joint with a thick silicon adhesive so that the piezoelectric vibrator does not contact the annular joint. ing. The piezoelectric vibrator is floated with a silicon adhesive to prevent abnormal noise, and the height of each piezoelectric vibrator may be different. Since the ultrasonic sensor is used alone, there is no significant problem in use even if the height and inclination vary.

  On the other hand, the parametric speaker is configured by arranging a plurality of such ultrasonic sounding bodies. The parametric speaker utilizes a phenomenon in which an ultrasonic wave generated by each ultrasonic sounding body is demodulated from an ultrasonic wave to an audible sound when it reaches or exceeds a sound pressure overlapping in the air. When the ultrasonic waves are radiated, only the central portion where the ultrasonic waves overlap is an audible sound, so that the parametric speaker is a speaker having a sharp directivity. For example, in a parametric speaker described in Patent Document 2, an ultrasonic sounding body is bonded to a substrate to constitute a speaker having a plurality of transmission sources.

JP 2004-128813 A JP 2011-234248 A

  However, in the parametric speaker as described above, since the ultrasonic sounding body is fixed to the substrate, the vibration is limited or the vibration is transmitted through the substrate and interferes with it, so that the function is not sufficiently exhibited. In the parametric speaker, the same fixing method as that of the ultrasonic sensor described above can be adopted. However, in this case, the height of each ultrasonic sounding body with respect to the substrate is different, and the ultrasonic wave generated by each ultrasonic sounding body is different. May cause the ultrasonic waves to cancel each other. In addition, each ultrasonic sounding body is inclined with respect to the substrate, and the direction in which the ultrasonic waves are emitted is likely to vary. In this case, the directivity of the parametric speaker varies.

  The present invention has been made in view of such circumstances, and provides a parametric speaker that can prevent variations in the direction of ultrasonic waves and phase shifts, and that does not hinder vibration of an ultrasonic sounding body, and a method for manufacturing the same. For the purpose.

  (1) In order to achieve the above object, the parametric speaker of the present invention is a parametric speaker that radiates ultrasonic waves from a plurality of oscillation sources, and is formed of a flat substrate provided with a wiring pattern and a rubber material. A support member provided on the substrate, a piezoelectric vibrator supported at a vibration node by the support member so that a height from the substrate is uniform, and provided on the piezoelectric vibrator. And a resonator that oscillates an ultrasonic wave.

  Thus, since the piezoelectric vibrator is supported so that the height from the substrate is uniform, it is possible to prevent variations in the direction of ultrasonic waves and phase shifts. Further, since the support member is formed of a rubber material and supports the vibration node of the piezoelectric vibrator, it is possible to prevent the vibration from being transmitted to the substrate without disturbing the vibration of the piezoelectric vibrator. As a result, the performance of the parametric speaker can be improved.

  (2) Further, the parametric speaker of the present invention is characterized in that the thickness of the support member is larger than the maximum displacement amount of the piezoelectric vibrator. Thereby, the piezoelectric vibrator does not come into contact with the substrate, and no abnormal noise is generated.

  (3) Moreover, the parametric speaker of the present invention is characterized in that the support member is formed of silicon rubber. Thus, while supporting the piezoelectric vibrator so that the height from the substrate is uniform, it is possible to prevent the vibration from being disturbed and to prevent the vibration from being transmitted to the substrate.

  (4) Further, the parametric speaker of the present invention is characterized in that the support member is formed in an annular shape. As a result, the manufacturing process for forming the support member in an annular shape, the installation on the substrate, and the handling of adhesion are facilitated.

  (5) Moreover, the parametric speaker according to the present invention is characterized in that the support member is composed of columnar bodies provided at three or more points on the substrate. Thereby, it is possible to prevent vibration, prevent vibration from being transmitted to the substrate, and enhance the function of the parametric speaker.

  (6) The method for manufacturing a parametric speaker according to the present invention is a method for manufacturing a parametric speaker that emits ultrasonic waves from a plurality of oscillation sources, and is formed of a rubber material and can support a vibration node of a piezoelectric vibrator. A step of preparing a support member formed in a shape, and a step of bonding an ultrasonic sounding body having the piezoelectric vibrator with the support member sandwiched between a flat substrate provided with a wiring pattern. In the bonding step, the piezoelectric vibrator is bonded to the support member after the piezoelectric vibrator is once pressed from above the support member bonded onto the substrate.

  In this way, once the piezoelectric vibrator is pressed against the substrate, the height of the piezoelectric vibrator from the substrate is made uniform, so that it is possible to prevent variations in the direction of ultrasonic waves and phase shift. Further, since the support member is formed of a rubber material and supports the vibration node of the piezoelectric vibrator, it is possible to prevent the vibration from being transmitted to the substrate without disturbing the vibration of the piezoelectric vibrator. As a result, an excellent performance parametric speaker can be manufactured.

  According to the present invention, since the piezoelectric vibrator is supported so that the height from the substrate is uniform, it is possible to prevent variation in the direction of ultrasonic waves and phase shift. Further, since the support member is formed of a rubber material and supports the vibration node of the piezoelectric vibrator, it is possible to prevent the vibration from being transmitted to the substrate without disturbing the vibration of the piezoelectric vibrator.

It is the schematic which shows the parametric speaker of this invention. It is a top view which shows an ultrasonic sounding body and a board | substrate. It is sectional drawing which shows an ultrasonic sounding body and a board | substrate. (A-1)-(d-2) It is the top view and sectional drawing which show the example of a supporting member. (A-1)-(d-2) It is the top view and side view which show the example of a supporting member.

  Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

(Configuration of parametric speaker)
FIG. 1 is a schematic diagram showing a parametric speaker 100. As shown in FIG. 1, the parametric speaker 100 has a configuration in which a plurality of ultrasonic sounding bodies 120 are supported on a substrate 110. When the power source 130 applies an alternating current to the piezoelectric vibrator 124 based on the resonance frequency and the ultrasonic sound generator 120 is driven, an ultrasonic wave is oscillated. In this way, the parametric speaker 100 radiates ultrasonic waves modulated with an audible sound signal from a plurality of oscillation sources into the medium, and demodulates the audible sound signal due to the nonlinearity of the medium.

  2 and 3 are a plan view and a sectional view showing the ultrasonic sounding body 120 and the substrate 110, respectively. The ultrasonic sounding body 120 includes a support member 121, a piezoelectric vibrator 124, and a resonator 127.

  The substrate 110 is formed of a resin in a flat plate shape, and wiring patterns 113 and 114 are provided. A plurality of ultrasonic sound generators 120 are periodically arranged on the substrate 110. The wiring patterns 113 and 114 are connected to the electrodes of the piezoelectric vibrator 124 of the ultrasonic sounding body 120 through lead wires 113a and 114a.

  The support member 121 is formed of a rubber material and is provided on the substrate 110 to support the entire ultrasonic sounding body 120. The support member 121 supports the piezoelectric vibrator 124 with a vibration node. Since the support member 121 is formed of a rubber material and supports the vibration node of the piezoelectric vibrator 124, the vibration of the piezoelectric vibrator 124 is not hindered and the vibration can be prevented from being transmitted to the substrate 110. For example, silicon rubber is preferably used as the rubber material. Accordingly, the piezoelectric vibrator 124 can be supported with sufficient elasticity so that the height from the substrate 110 becomes uniform, and since it has a displaceable flexibility, it is possible to prevent the vibration from being disturbed. Can be prevented from being transmitted to.

  The support member 121 has a predetermined thickness and supports the piezoelectric vibrator 124 so that the height from the substrate 110 to the support position is uniform. The height from the substrate 110 to the support position is uniform regardless of the projection position on the substrate 110 for one support member 121, and the height from the substrate 110 to the support position is also uniform for the support members 121. Thereby, the dispersion | variation in the direction of an ultrasonic wave and the shift | offset | difference of a phase can be prevented.

  The thickness of the support member 121 is preferably larger than the maximum displacement amount of the piezoelectric vibrator 124. Thereby, the piezoelectric vibrator 124 does not come into contact with the substrate 110 at the time of displacement, and no abnormal noise is generated. Details of each shape example of the support member 121 will be described later. However, if the displacement amount is too large, the support member 121 may be vibrated due to bending vibration of the piezoelectric vibrator 124, so that the thickness is preferably 1 mm or less.

  The piezoelectric vibrator 124 is formed by a piezoelectric element 125 and a metal plate 126. The piezoelectric element 125 is formed in a disk shape with piezoelectric ceramics and electrodes, and expands and contracts when a voltage is applied. The metal plate 126 is formed in a disc shape having a diameter larger than that of the piezoelectric element 125, and is bonded to one main surface of the piezoelectric element 125, thereby restricting expansion and contraction of the piezoelectric element 125. Due to such a configuration, when an alternating current is applied to the piezoelectric element 125, the piezoelectric vibrator 125 bends and vibrates. The resonator 127 is provided on the piezoelectric vibrator 124 and oscillates an ultrasonic wave.

(Shape of support member)
4A-1 to 4D-2 are a plan view and a cross-sectional view illustrating an example of the support member 121. FIG. As in the example shown in FIGS. 4A-1 to 4D-2, the support member 121 is preferably formed in an annular shape. As a result, the manufacturing process for forming the support member 121 in an annular shape, the installation on the substrate, and the handling of adhesion are facilitated. The support member 121 can be kept at a constant height and not tilted by pressing the piezoelectric vibrator 124. Further, the thickness of the support member 121 where the piezoelectric vibrator 124 is supported is made uniform. For example, when bonding on the circumference, as shown in the figure, the support member 121 may be a ring having a square, triangular, kamaboko or trapezoidal cross section.

  Bonding of the piezoelectric vibrator 124 and the support member 121 is performed on the circumference as described above or at three or more positions. 5A-1 to 5D-2 are a plan view and a side view showing an example of the support member 121. FIG. In the example of FIGS. 5A-1 to 5D-2, the support member 121 is configured by columnar bodies provided at three or more points on the substrate 110. Thereby, while preventing a vibration, it can prevent that a vibration is transmitted to the board | substrate 110, and can improve the function of a parametric speaker.

  The shape of the cross section may be other than the above as long as the support member 121 has a uniform thickness and is in contact with the piezoelectric vibrator 124 on the circumference. When the columnar support members 121 are bonded, it is preferable to use three or more of the same columnar bodies as shown in FIGS. 5 (a-1) to (d-2). The columnar body can be formed in a columnar shape, a columnar shape having a dome shape at the tip, a rectangular column, or a conical shape. Even in the case of bonding with a columnar body, other shapes may be used as long as the thickness is uniform.

(Manufacturing method of parametric speaker)
A method for manufacturing the parametric speaker configured as described above will be described. First, a support member 121 made of a rubber material and having a shape capable of supporting the vibration node of the piezoelectric vibrator 124 is prepared. An ultrasonic sounding body 120 having a piezoelectric vibrator 124 is bonded to a flat substrate 110 provided with a wiring pattern with a support member 121 interposed therebetween. In the bonding process, the piezoelectric vibrator 124 is temporarily pressed from above the support member 121 bonded onto the substrate 110. Thereafter, the piezoelectric vibrator 124 is bonded to the support member 121. For example, a silicon adhesive is preferably used as the adhesive.

  By pressing the piezoelectric vibrator 124 once, the height of the ultrasonic sounding body 120 from the substrate 110 is equal to the height of the support member 121 and is parallel to the surface of the substrate 110. Note that, by pressing once, the piezoelectric vibrator 124 comes into contact with a portion of the support member 121 that does not normally contact, but since the support member 121 is made of a rubber material such as silicon rubber, abnormal noise can be prevented.

  In addition, wiring patterns 113 and 114 are provided on the substrate 110. After bonding by the above method, all the ultrasonic sounding bodies 120 are connected to the wiring patterns 113 and 114 and the lead wires 113a and 114a of the substrate 110. The parametric speaker 100 can be manufactured. Note that the lead wires 113a and 114a are connected to the ultrasonic sounding body 120 side before bonding.

100 Parametric speaker 110 Substrate 113, 114 Wiring pattern 113a, 114a Lead wire 120 Ultrasonic sounding body 121 Support member 124 Piezoelectric vibrator 125 Piezoelectric element 126 Metal plate 127 Resonator 130 Power supply

Claims (6)

A parametric speaker that emits ultrasonic waves from a plurality of oscillation sources,
A flat substrate provided with a wiring pattern;
A support member formed of a rubber material and provided on the substrate;
A piezoelectric vibrator supported at a vibration node by the support member so that the height from the substrate is uniform;
A parametric speaker comprising: a resonator provided on the piezoelectric vibrator and configured to oscillate ultrasonic waves.   The parametric speaker according to claim 1, wherein a thickness of the support member is larger than a maximum displacement amount of the piezoelectric vibrator.   The parametric speaker according to claim 1, wherein the support member is made of silicon rubber.   The parametric speaker according to any one of claims 1 to 3, wherein the support member is formed in an annular shape.   The parametric speaker according to any one of claims 1 to 3, wherein the support member is configured by columnar bodies provided at three or more points on the substrate. A method of manufacturing a parametric speaker that emits ultrasonic waves from a plurality of oscillation sources,
A step of preparing a support member formed of a rubber material and having a shape capable of supporting a vibration node of the piezoelectric vibrator;
Adhering an ultrasonic sounding body having the piezoelectric vibrator across the support member on a flat substrate provided with a wiring pattern,
In the bonding step, the piezoelectric vibrator is bonded to the support member after once pressing the piezoelectric vibrator from the support member bonded to the substrate.

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