JPS6281200A - Ultrasonic ceramic microphone - Google Patents

Abstract

PURPOSE:To simplify an assembly work and to drastically cut down the influence of an external impulse on a vibrating part by constituting the titled microphone by a supporter consisting of an elastic material and a bimorph resonator produced by laminating a piezoelectric ceramic resonator on a diaphram. CONSTITUTION:For an annular flange part 8a at the peripheral end and the diaphram 8 comprising a vibrating plane 8b of uniform plane, a metallic aluminum or a ceramic alumina is used. The bimorph resonator is constituted by laminating the piezoelectric ceramic resonator 1 on the vibrating plane 8b. The thickness of the flange part 8a provided at the periphery of the diaphram 8 is made 1.5 times or above the diaphram 8's thickness to minimize the characteristic-variation when receiving the external pressure. A supporter 9 consists of an elastic material such as silicone rubber or butyl rubber, etc., and has a bottom-forming part 9a. At the opening end of the supporter 9, a horn-shaped conical part 9b is formed, and a groove part 9c is provided in its peripheral side to make its mounting to an equipment easy. Also, in the inner-side of the supporter 9, a holding part to hold the periphery of the diaphram 8 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultrasonic ceramic microphone used in equipment such as an ultrasonic transmitter/receiver used outdoors, such as an ultrasonic distance meter obstacle detection system using ultrasonic waves. It is something.

Conventional technology Conventionally, this type of ultrasonic ceramic microphone has a tertiary
The configuration was as shown in the figure. In FIG. 3, a piezoelectric ceramic vibrator 1 is bonded to the bottom surface 2a of a cylindrical case 2 having a truncated conical bottom surface to form a bimorph vibrating section integrated with the cylindrical case. 3 is a ring-shaped resonator fixed inside the cylindrical case 2. 4 is terminal sa, s
This is a terminal plate formed by implanting the elastic member 6 into the open end of the cylindrical case 2. 7a.

7b is a lead wire that connects the upper and lower electrode surfaces of the piezoelectric ceramic vibrator 1 and the terminals 5a and 8b.

Problems to be Solved by the Invention In such a conventional configuration, since the cylindrical case with the vibration part integrated therein is mechanically supported when attached to the device, vibrations are likely to be suppressed depending on the supporting state. Therefore, the characteristics tend to change easily, the structure becomes complicated, and it takes time to assemble. The present invention solves these problems.
The purpose is to provide a structure with small changes in characteristics depending on the support method, and to facilitate assembly.

Means for Solving the Problem In order to solve this problem, the present invention provides a diaphragm in which the thickness of the outer peripheral edge is 1.6 times or more thicker than the thickness around the center. A piezoelectric ceramic vibrator is laminated,
a bimorph vibrating body (made of an elastic material), a support body having a holding part for holding the vibrating plate, having a horn-shaped radiating part at one end opening, and having a bottom surface at the other end. It is something.

Effect: With this configuration, the outer peripheral edge of the diaphragm of the vibrating part is thickened to increase vibration energy, and a horn-shaped radiating part is formed at the open end of the support, increasing the acoustic radiation level and emitting high-power ultrasonic waves. At the same time, since the support body is made of an elastic member, even if an external shock is applied, the support body absorbs the vibration, and the influence on the vibrating part is significantly reduced.

Embodiment FIG. 1 is a sectional view of an ultrasonic ceramic microphone according to an embodiment of the present invention. In FIG. 1, 1 is a piezoelectric ceramic vibrator. Reference numeral 8 denotes a diaphragm having a ring-shaped collar portion 8a of different thickness at the outer peripheral end and a vibrating surface 8b having a uniform plane, and is made of metal aluminum or ceramic alumina. A bimorph vibrator was constructed by bonding the piezoelectric ceramic vibrator 1 to the vibrating surface 8b. The thickness of the diaphragm 8 is tO-8rIrln+outer diameter φ13.0. , the thickness of the outer peripheral edge of the diaphragm is t 5-01 rrm r width 2. C)+o
a, thickness of piezoelectric generator vibrator t Oo-31a outer diameter φ8.
By setting 0+ma, the resonance frequency is 40KH.
z, an output sound pressure level of 116 dB is obtained.

As shown in the relationship with the output sound pressure level change due to external pressure, when the thickness of the imaging plate 8 is to, 6non or more, the thickness of the flange 8a provided around the diaphragm is 1.6 times or more than the diaphragm. By doing so, we created a structure that minimizes changes in characteristics when external pressure is applied. 9 is made of an elastic material such as silicone rubber or butyl rubber, has a bottomed portion 9a, has a horn-shaped radiating portion 9b formed at the other open end, and has a recessed portion 9C on the outer periphery to facilitate attachment to equipment. This is a support provided. A holding portion for holding the outer peripheral end of the diaphragm 8 was formed inside the support body 9 . A hole 10a1o is provided in the bottomed surface of the support 9.
b, and connect the lead wires 11a and 11b for extracting electricity from both electrodes of the bimorph vibrator, and pass through the holes 10 and 10b to connect the lead wires 11a and 11b.
12 is an adhesive for sealing the holes 10a and 10b. The piezoelectric ceramic vibrator and the lead wire connection portion were configured to be sealed with a support.

Effects of the Invention As described above, according to the present invention, assembly is easy due to the simple structure consisting of a support and a bimorph vibrator in which a piezoelectric ceramic vibrator is laminated to a diaphragm, and it is easier to assemble than an elastic material. Since the vibrating part is covered with a support, the external support pressure can be buffered, the vibration of the vibrating part is not attenuated, and the change in characteristics is small. In addition, since the piezoelectric generator vibrator and the connection part are sealed, it has a drip-proof structure that can be used for equipment used outdoors.By changing the thickness between the outer peripheral edge and the center area of the 0 diaphragm, vibration can be reduced. In addition to increasing the resonance Q and increasing the electro-acoustic conversion efficiency to create a high-output ultrasonic transducer, the acoustic characteristics can be adjusted by arbitrarily setting the horn-shaped radiating part that is integrated with the support. It also has the effect of improving acoustic output.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an ultrasonic ceramic microphone according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the relationship between the diaphragm thickness ratio of the present invention and output sound pressure level change due to external pressure, and FIG. The figure is a sectional view showing a conventional ultrasonic ceramic microphone. 1...Piezoelectric S unit vibrator, 8...Picture plate, 8a...Brim portion, 8b...Vibration surface,
9...Support body, 9a...Bottomed surface, 9b
...Radiation part, 9C...Concave part, 10a,
10b...hole, 11a, 11b...
Lead wire, 12...Adhesive. Agent's name: Patent attorney Toshi Nakao and 1 other person - Piezoelectric 1 person 21 noodles Rb - Ikken Kanbacterial? -f Salary Qa, ---11Δ qb---Bamurano 9c-Kojizuka et al., fDb=Constant country f report 1fb-m-Word line Figure 2 Male Figure 3

Claims (1)

[Claims] A diaphragm made of an elastic material, including a diaphragm whose outer peripheral edge is at least 1.5 times thicker than the center periphery, a piezoelectric ceramic oscillator bonded to the center of the diaphragm to form a bimorph oscillator, and an elastic material. An ultrasonic ceramic microphone comprising a support body having a holding portion for holding the diaphragm, a horn-shaped radiating portion at one end opening, and a bottom surface at the other end.