JP2000188800A - Drip-proof type ultrasonic microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a drip-proof type ultrasonic microphone capable of short- distance detection by preventing the excitation of a plus lead which causes an increase reverberation time. SOLUTION: The drip-proof type ultrasonic microphone is constituted by arranging a disk-like piezoelectric ceramics 2 on the inside surface of the bottom part of a bottomed cylindrical shape vibration case 1, bringing the vibration case 1 into contact with the lower surface of the piezoelectric ceramics 2, erecting a lead 3 on the upper surface of the piezoelectric ceramics 2 and surrounding the outer peripheral part of the piezoelectric ceramics 2 with a ring silicon 4 of elastic body which is fixed to the inner peripheral part of the vibration case 1. In this case, a projection part 4b which comes into contact with an exposed part (3a) of the lead 3 led out of the piezoelectric ceramics 2 is successively provided on the inner peripheral surface 4a of the ring silicon 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / reception integrated drip-proof ultrasonic microphone.

[0002]

2. Description of the Related Art A conventional drip-proof ultrasonic microphone is one in which a tone burst wave is input to a piezoelectric ceramic 2 at a constant or arbitrary period and excited to generate a voltage.
Both transmission and reception are possible. FIG.
17 to 17 show the configuration of a conventional drip-proof ultrasonic microphone. A disc-shaped piezoelectric ceramic 2 is fixed to the inner surface of the bottom of the bottomed cylindrical vibration case 1 with an adhesive. The vibration case 1 is formed of an aluminum material, and serves as one conductor when exciting the piezoelectric ceramics 2 to generate a voltage. The piezoelectric ceramic 2 is a PZT-based ceramic, and a plus lead 13 is connected to the outer peripheral end of the upper surface by soldering. Ring-shaped ring silicon 4
Is formed of an elastic body and is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1 to prevent excitation of the straight pipe portion 1a of the vibration case 1. A sound absorbing felt 5 is disposed above the ring silicon 4 so as to cover the upper surface of the piezoelectric ceramics 2 and serves to absorb and attenuate sound waves generated inside the vibration case 1. At the upper part of the sound absorbing felt 5, a sealing silicon 6 made of an elastic material having a low initial fluidity is disposed to prevent a sealing silicon 11 having a low fluidity, which will be described later, from flowing into a void portion of the sound absorbing felt 5. . A printed circuit board 7 is held in close contact with the upper surface of the bonding silicon 6,
A pattern is provided on the upper surface, and a minus lead 9 is provided horizontally on the upper surface of the printed circuit board 7 on the side opposite to the side where the plus lead 13 protrudes. The end opposite to the side where the plus lead 13 protrudes from the upper part of the sealing silicon 6 is missing, and the missing portion 6a is filled with the conductive adhesive 8 to mate the vibration case 1 with the minus lead 9. While holding, conduction between the vibration case 1 and the negative lead 9 is achieved. The plus lead 13 and the minus lead 9 and the connector cable 10 are soldered to the land portion of the pattern, and the plus lead 13 and the plus side and the minus lead 9 of the connector cable 10 are soldered.
And the negative side of the connector cable 10 is electrically connected. The sealing silicon 11 is filled from the upper surface of the printed circuit board 7 to the open rear end 1c of the vibration case 1 to prevent foreign matter from entering the inside of the microphone.

[0003]

The above-mentioned drip-proof type ultrasonic microphone has the following problems when used as a sensor for monitoring the vicinity of a vehicle. FIG. 18 illustrates the principle of the ultrasonic microphone.

FIG. 18A shows a waveform of a transmission applied voltage, and FIG. 18B shows a voltage waveform of a reception signal. T1 is a transmission time, which is a time during which the ultrasonic microphone is excited by the transmission applied voltage. T2 is the time from transmission to the end of reverberation. The ultrasonic microphone is vibrated by the transmission applied voltage to start oscillating the ultrasonic wave, and then the applied voltage is cut off to eliminate the vibration of the ultrasonic microphone. Until the time. T3 is a reflection time, which is a time until the ultrasonic wave is reflected by the object and returns. The distance L to the symmetric object is determined by the reflection time T3, and is obtained from L = (331 + 0.6t) T3 / 2 (m), where t (° C.) is the ambient temperature. From the above, if the time T2 from transmission to the end of reverberation becomes longer, the reflection time T3 cannot be detected, and particularly, a short distance where the reflection time T3 is short cannot be measured.

In the conventional ultrasonic microphone, when the radial expansion and contraction of the piezoelectric ceramics 2 is converted into longitudinal vibration by the vibration case 1, the plus lead 13 is also excited at the same time. As a result, the transmission shown in FIG. The time T2 from when the reverberation disappears until the reverberation disappears increases, making it impossible to detect a short-distance object. For this reason, despite the high possibility of being installed outdoors as a sensor element for an automatic door and a parking lot, there is a problem in that an open type ultrasonic microphone having little reverberation and not having a drip-proof structure is used. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent excitation of a plus lead, which causes an increase in reverberation time, by
An object of the present invention is to provide a drip-proof ultrasonic microphone capable of detecting a short distance.

[0007]

According to a first aspect of the present invention, there is provided a drip-proof ultrasonic microphone having a bottomed cylindrical vibration case.
A disc-shaped piezoelectric ceramic 2 is disposed on the inner surface of the bottom of the piezoelectric ceramic 2, the lower surface of the piezoelectric ceramic 2 is brought into contact with the vibration case 1, the lead 3 is erected on the upper surface of the piezoelectric ceramic 2, and the outer periphery of the piezoelectric ceramic 2 is In a drip-proof type ultrasonic microphone fixed to the inner peripheral surface 1b of the liquid crystal device 1 and surrounded by a ring-shaped ring silicon 4 formed of an elastic body, the exposed portion 3 of the lead 3 pulled out from the piezoelectric ceramic 2
a protruding portion 4 b which is in close contact with the inner peripheral surface 4 of the ring silicon 4.
a.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the drip-proof ultrasonic microphone adheres to the exposed portion 3a of the lead 3 and the solder 20 for fixing the lead 3 to the piezoelectric ceramics 2. The protrusion 4b is provided continuously on the inner peripheral surface 4a of the ring silicon 4.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, the exposed portion 3a of the lead 3 and the lead 3
Is provided continuously on the inner peripheral surface 4a of the ring silicon 4 so as to cover the entire periphery of the solder 20 that is fixed to the piezoelectric ceramics 2.

According to a fourth aspect of the present invention, there is provided a drip-proof ultrasonic microphone in which a disk-shaped piezoelectric ceramics 2 is disposed on the inner surface of the bottom of a cylindrical vibration case 1 having a bottom, and the lower surface of the piezoelectric ceramics 2 is vibrated. A ring-shaped ring silicon formed of an elastic body, which is brought into contact with the case 1, a lead 3 is erected on the upper surface of the piezoelectric ceramic 2, and an outer peripheral portion of the piezoelectric ceramic 2 is fixed to an inner peripheral surface 1 b of the vibration case 1. In the drip-proof ultrasonic microphone surrounded by 4, the exposed portion 3a of the lead 3 projecting upward from the piezoelectric ceramic 2 and the projecting portion 4b covering the outer periphery of the solder 20 for fixing the lead 3 to the piezoelectric ceramic 2 are formed by a ring. It is provided continuously on the inner peripheral surface 4a of silicon, and the protrusion 4a is slightly larger than the diameter of the solder 20 having the lead 3 as a central axis and fixing the lead 3 to the piezoelectric ceramics 2. A straight tubular opening 4c having a diameter is provided, and the exposed portion 3a of the lead 3 and the solder 20 for fixing the lead 3 to the piezoelectric ceramics 2 are inserted through the straight tubular opening 4c. It is characterized by being filled with an elastic body 14 having fluidity.

According to a fifth aspect of the present invention, there is provided a drip-proof ultrasonic microphone in which a disk-shaped piezoelectric ceramics 2 is disposed on the inner surface of the bottom of a cylindrical vibration case 1 having a bottom, and the lower surface of the piezoelectric ceramics 2 is vibrated. A ring-shaped ring silicon formed of an elastic body, which is brought into contact with the case 1, a lead 3 is erected on the upper surface of the piezoelectric ceramic 2, and an outer peripheral portion of the piezoelectric ceramic 2 is fixed to an inner peripheral surface 1 b of the vibration case 1. In the drip-proof ultrasonic microphone surrounded by 4, the exposed portion 3a of the lead 3 projecting upward from the piezoelectric ceramic 2 and the projecting portion 4b covering the outer periphery of the solder 20 for fixing the lead 3 to the piezoelectric ceramic 2 are formed by a ring. A straight tubular opening 4d surrounding the solder 20 for fixing the lead 3 to the piezoelectric ceramics 2 is provided in the projecting portion 4b so as to be continuous with the inner peripheral surface 4a of the silicon 4.
And a lead 3 as a central axis on the top,
In addition, a tapered opening 4e having an upper opening circle larger than the lower opening circle is provided, a solder 20 for fixing the lead 3 to the piezoelectric ceramics 2 is fitted into the straight tubular opening 4d, and a tapered opening 4e is fitted into the tapered opening 4e. It is characterized in that the exposed portion 3a of the lead 3 is inserted, and the elastic body 14 having initial fluidity is filled in the tapered opening 4e.

In a drip-proof ultrasonic microphone according to a sixth aspect of the present invention, a disk-shaped piezoelectric ceramic 2 is disposed on the inner surface of the bottom of a cylindrical vibration case 1 having a bottom, and the lower surface of the piezoelectric ceramic 2 is vibrated. A drip-proof type in which a lead 3 is erected on the upper surface of a piezoelectric ceramic 2 while being in contact with the case 1, and an outer peripheral portion of the piezoelectric ceramic 2 is surrounded by a ring-shaped ring silicon 4 fixed to an inner peripheral surface 1 b of the vibration case 1. In the ultrasonic microphone, the exposed portion 3a of the lead 3 projecting above the piezoelectric ceramic 2 and the lead 3 are connected to the piezoelectric ceramic 2
A projecting portion 4b for covering the outer periphery of the solder 20 adhered to the inner surface 4a of the ring silicon 4 is provided continuously.
b, a taper having the lead 3 as a central axis, the diameter of the lower opening circle being slightly larger than the diameter of the outer peripheral circle of the solder 20 for fixing the lead 3 to the piezoelectric ceramics 2, and the upper opening circle being larger than the lower opening circle. An opening 4f is provided, and the elastic body 14 having initial fluidity is filled in the tapered opening 4f.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The essential parts of the drip-proof microphone of the present invention are in the ring silicon 4 and the configuration other than the main parts is the same as that of the conventional example described above. Is omitted.

A drip-proof ultrasonic microphone according to the first embodiment will be described with reference to FIGS. In this example, as shown in FIG. 1, a ring-shaped ring silicon 4 formed of an elastic body is fixed to an inner peripheral surface 1b of a straight pipe portion 1a of a vibration case 1, and FIG. 2 (a) and FIG. As shown, a protruding portion 4 b is provided continuously on the inner peripheral surface 4 a of the ring silicon 4, and the tip portion thereof is brought into close contact with the exposed portion 13 a of the plus lead 13. Thus, the ring silicon 4 prevents the straight pipe portion 1a of the vibration case 1 from being excited, and the protruding portion 4b of the ring silicon 4 prevents the positive lead 13 from being excited, thereby shortening the reverberation time, and Can be detected.

Next, a drip-proof ultrasonic microphone according to a second embodiment will be described with reference to FIGS. This example is shown in FIG.
As shown in FIGS. 4A and 4B, a ring-shaped ring silicon 4 formed of an elastic body is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1, and as shown in FIGS. A protruding portion 4b is provided continuously on the inner peripheral surface 4a of the silicon 4, and its tip is brought into close contact with the exposed portion 13a of the plus lead 13 and the solder 20 for fixing the plus lead 13 to the piezoelectric ceramics 2. . Thereby, the ring silicon 4
The excitation of the straight pipe portion 1a of the vibration case 1 is prevented by the
3 is prevented, and even the vibration of the solder 20 is prevented, so that the reverberation time can be further shortened and a reflected wave at a shorter distance can be detected.

Next, a drip-proof ultrasonic microphone according to a third aspect will be described with reference to FIGS. This example is shown in FIG.
As shown in FIGS. 6A and 6B, a ring-shaped ring silicon 4 formed of an elastic body is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1, and as shown in FIGS. The protruding portion 4b is provided continuously on the inner peripheral surface 4a of the silicon 4, and the tip portion is covered with a solder 20 for fixing the exposed portion 13a of the plus lead 13 and the plus lead 13 to the piezoelectric ceramics 2. . Thus, the ring silicon 4 prevents the straight pipe portion 1a of the vibration case 1 from being excited, and the protruding portion 4b of the ring silicon 4 prevents the positive lead 1
3, the vibration of the solder 20 can be more reliably prevented, the reverberation time can be stably shortened, and the detection of a reflected wave at a short distance can be stably obtained.

Next, a drip-proof ultrasonic microphone according to a fourth aspect will be described with reference to FIGS. This example is shown in FIG.
As shown in FIG. 8, a ring-shaped ring silicon 4 formed of an elastic material is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1, and as shown in FIGS. An exposed portion 13a of the plus lead 13 protruding above the ceramics 2 and a projecting portion 4b covering the outer periphery of the solder 20 for fixing the plus lead 13 to the piezoelectric ceramics 2 are continuously provided on the inner peripheral surface 4a of the ring silicon 4. , On the protruding portion 4b,
A straight tubular opening 4c having the plus lead 13 as a central axis and having a diameter slightly larger than the diameter of the solder 20 is provided, and the exposed portion 3a of the plus lead 13 and the solder 20 are inserted through the straight tubular opening 4c. The straight tubular opening 4c is filled with an elastic body 14 having initial fluidity. As described above, the ring silicon 4 fixed to the inner peripheral surface 1b of the straight tube portion 1a of the vibration case 1 prevents the excitation of the straight tube portion 1a of the vibration case 1 and the initial flow. Straight opening 4c for filling the elastic body 14 having elasticity
Is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1 by aligning the ring silicon 4 having the shape of the plus lead 13 with the elastic body 14 having initial fluidity in the straight tubular opening 4c. This method is a method of filling and bringing the plus lead 13 and the solder 20 into close contact with the ring silicon 4, so that it is easy to manufacture, and the exposed portion 3 a of the plus lead 13 and the solder 20
In addition, the adhesion between the elastic body 14 having initial fluidity surrounding the exposed portion 13a of the plus lead 13 and the solder 20 and the ring silicon 4 surrounding the periphery thereof can be increased. As a result, the excitation of the plus lead 13 can be achieved. As a result, the effect of preventing the vibration of the solder 20 and the effect of preventing the vibration of the solder 20 can be enhanced, the reverberation time can be shortened, and the reflected wave at a shorter distance can be detected. Note that FIG.
3A and 3B are a top view and a cross-sectional view of the ring silicon 4 used in this example.

Next, a drip-proof ultrasonic microphone according to a fifth aspect will be described with reference to FIGS. In this example, as shown in FIG. 10, a ring-shaped ring silicon 4 formed of an elastic body is fixed to an inner peripheral surface 1b of a straight pipe portion 1a of a vibration case 1, and FIGS. 11 (a) and 11 (b). As shown, a plus lead 13 projecting upward from the piezoelectric ceramics 2
A projecting portion 4b for covering the outer periphery of the solder 20 for fixing the exposed portion 13a and the plus lead 13 to the piezoelectric ceramics 2 is continuously provided on the inner peripheral surface 4a of the ring silicon 4, and the projecting portion 4b is provided on the projecting portion 4b. Is provided, and a plus lead 13 is provided as a central axis on the top thereof,
In addition, a tapered opening 4e having an upper opening circle larger than the lower opening circle is provided, solder 20 is fitted into the straight tubular opening 4d, and a plus lead 1 is inserted into the tapered opening 4e.
3 through which the exposed portion 3a is inserted, and the tapered opening 4e is filled with an elastic body 14 having initial fluidity. As described above, the ring silicon 4 formed of an elastic body and fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1
The ring silicon 4 having the tapered opening 4 e for filling the elastic body 14 having the initial fluidity is prevented from being excited by the straight pipe portion 1 a of the vibration case 1 by adjusting the position of the plus lead 13. A method in which the positive lead 13 and the ring silicon 4 are adhered to each other by being fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1 and filling the tapered opening 4e with an elastic body 14 having initial fluidity. Therefore, the filling of the elastic body 14 is simple, the manufacturing is easy, and the exposed portion 13a of the plus lead 13 and the exposed portion 1 of the plus lead 13 are formed.
The adhesion between the elastic body 14 having the initial fluidity surrounding the 3a and the ring silicon 4 surrounding the periphery thereof can be increased, and as a result, the effect of preventing the excitation of the plus lead 13 can be enhanced, and the reverberation time can be reduced. Shortening makes it possible to detect reflected waves at shorter distances. FIGS. 12A and 12B are a top view and a cross-sectional view of the ring silicon 4 used in this example.

A drip-proof ultrasonic microphone according to claim 6 will be described with reference to FIGS. In this example, as shown in FIG. 13, a ring-shaped ring silicon 4 formed of an elastic body is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1, and FIG. 14 (a) and FIG. As shown, a plus lead 13 projecting upward from the piezoelectric ceramics 2
A protruding portion 4b covering the outer periphery of the solder 20 for fixing the exposed portion 13a and the plus lead 13 to the piezoelectric ceramics 2 is provided continuously on the inner peripheral surface 4a of the ring silicon 4, and the plus portion is provided on the protruding portion 4b. 13 is a central axis, and the diameter of the lower opening circle is slightly larger than the diameter of the outer peripheral circle of the solder 20 for fixing the plus lead 13 to the piezoelectric ceramics 2, and the upper opening circle is larger than the lower opening circle. 4f, and the elastic body 14 having initial fluidity is filled in the tapered opening 4f. Thus, the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1 is formed of an elastic body.
The ring silicon 4 is fixed to the ring silicon 4 to prevent the straight pipe portion 1a of the vibration case 1 from being excited, and the ring silicon 4 having a tapered opening 4f for filling the elastic body 14 having initial fluidity is added. It is fixed to the inner peripheral surface 1b of the straight pipe portion 1a of the vibration case 1 in accordance with the position of the lead 13, and the tapered opening 4f is filled with an elastic body 14 having initial fluidity, and the plus lead 13 and the solder 20 and the ring silicon 4 are adhered to each other, so that the elastic body 14 can be easily filled, the manufacturing is easy, the exposed portion 13a of the plus lead 13 and the solder 20, and the exposed portion 13a of the plus lead 13 and Elastic body 14 having initial fluidity surrounding solder 20
Therefore, the adhesion between the ring silicon 4 surrounding the periphery thereof can be enhanced, and as a result, the effect of preventing the excitation of the plus lead 13 and the effect of preventing the vibration of the solder 20 can be further improved, and the reverberation time can be shortened. This makes it possible to detect reflected waves at shorter distances. FIGS. 15A and 15B are a top view and a sectional view of the ring silicon 4 used in this example.

[0020]

According to the first aspect of the present invention, the straight pipe of the vibration case is formed of an elastic body and fixed to the inner peripheral surface of the straight pipe portion of the vibration case by the ring silicon. In addition to preventing the excitation of the section, the excitation of the lead is prevented to shorten the reverberation time, and it is possible to detect a reflected wave in a short distance.

According to the second aspect of the present invention, in addition to the effects of the first aspect, the excitation of the leads and the vibration of the solder are also prevented.
The reverberation time is made shorter, and a reflected wave at a shorter distance can be detected.

According to the third aspect of the present invention, in addition to the effects of the second aspect, the prevention of lead excitation and the prevention of solder vibration can be further ensured. The reverberation time can be stably shortened, and the detection of a reflected wave in a short distance can be obtained stably.

In the invention according to a fourth aspect of the present invention, the straight pipe portion of the vibration case is formed of an elastic body and is fixed to the inner peripheral surface of the straight pipe portion of the vibration case by ring silicon. In addition to preventing the excitation of, the ring silicon provided in the projecting portion with a straight tubular opening for filling the elastic body with initial fluidity is fixed to the inner peripheral surface of the vibration case by aligning it with the position of the lead, Since the straight pipe opening is filled with an elastic body having initial fluidity to bring the lead and the ring silicon into close contact with each other,
It is easy to manufacture, and it is possible to increase the adhesion between the exposed portion of the lead, the elastic body having initial fluidity surrounding the exposed portion of the lead, and the ring silicon surrounding the periphery thereof, thereby preventing the excitation of the lead, In addition, the effect of preventing the vibration of the solder can be enhanced, the reverberation time can be shortened, and the reflected wave at a shorter distance can be detected.

According to the fifth aspect of the present invention, the straight pipe portion of the vibration case is formed by an elastic body and fixed to the inner peripheral surface of the straight pipe portion of the vibration case by the ring silicon. A ring silicon having a tapered opening for filling an elastic body having initial fluidity is fixed to the inner peripheral surface of the vibration case in accordance with the position of the lead, while preventing excitation, and the tapered opening is formed. Since the lead and the ring silicon are brought into close contact with each other by filling an elastic body having initial fluidity, the filling of the elastic body is simple, the manufacturing is easy, and the exposed portion of the lead and the initial portion surrounding the exposed portion of the lead are easily formed. Adhesion between the elastic body with fluidity and the ring silicon surrounding it can be increased, the effect of preventing lead excitation can be enhanced, the reverberation time can be shortened, and short distance detection becomes possible. .

According to a sixth aspect of the present invention, the straight pipe portion of the vibration case is formed of an elastic body and is fixed to the inner peripheral surface of the straight pipe portion of the vibration case by ring silicon. Ring silicon having a tapered opening for filling an elastic body having initial fluidity is fixed to the inner peripheral surface of the vibration case in accordance with the position of the lead, and the tapered opening is prevented. The ring is filled with an elastic material having initial fluidity and the solder for fixing the lead to the lead and the piezoelectric ceramics is brought into close contact with the ring silicon, so that the filling of the elastic material is simple, the manufacturing is easy, and the lead is exposed. Portion and the solder, the exposed portion of the lead and the elastic body having initial fluidity surrounding the solder, and the ring silicon surrounding the periphery thereof can be made to have high adhesion, thereby preventing the excitation of the lead and the solder. Vibration prevention Fruit can be increased, and shorter reverberation time, allowing more short distance of the reflected wave detection.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to an example of an embodiment of the present invention.

2A is an enlarged longitudinal sectional view of a portion A in FIG. 1, and FIG. 2B is a sectional view taken along line BB in FIG. 2A.

FIG. 3 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to another example of the embodiment of the present invention.

4 (a) is an enlarged longitudinal sectional view of a portion A in FIG. 3, and FIG. 4 (b) is a sectional view taken along line BB in FIG. 4 (a).

FIG. 5 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to another example of the embodiment of the present invention.

6 (a) is an enlarged longitudinal sectional view of a portion A in FIG. 5, and FIG. 6 (b) is a sectional view taken along line BB in FIG. 6 (a).

FIG. 7 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to another example of the embodiment of the present invention.

8 (a) is an enlarged vertical cross-sectional view of a portion A in FIG. 7, and FIG. 8 (b) is a cross-sectional view taken along line BB in FIG. 8 (a).

FIG. 9A is a top view of the ring silicon of FIG. 7,
FIG. 10B is a sectional view taken along line CC of FIG. 9A.

FIG. 10 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to another example of the embodiment of the present invention.

11A is an enlarged longitudinal sectional view of a portion A in FIG. 10, and FIG.
FIG. 12 is a sectional view taken along line BB of FIG.

FIG. 12 (a) is a top view of the ring silicon of FIG. 10,
FIG. 13B is a sectional view taken along line CC of FIG.

FIG. 13 is a longitudinal sectional view of a drip-proof ultrasonic microphone according to another example of the embodiment of the present invention.

14A is an enlarged longitudinal sectional view of a part A in FIG. 13, FIG.
FIG. 15 is a sectional view taken along line BB of FIG.

FIG. 15 (a) is a top view of the ring silicon of FIG. 13,
FIG. 15B is a cross-sectional view taken along line CC of FIG.

FIG. 16 is a longitudinal sectional view of a conventional drip-proof ultrasonic microphone.

17A is an enlarged longitudinal sectional view of a portion A in FIG. 16; FIG.
FIG. 17 is a sectional view taken along line BB of FIG. 16.

FIG. 18 is an explanatory diagram of the principle of the ultrasonic microphone,
(A) is a transmission applied voltage waveform diagram, (b) is a received signal voltage waveform diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration case 1b Inner peripheral surface 2 Piezoelectric ceramics 3 Lead 3a Exposed part 4 Ring silicon 4a Inner peripheral surface 4b Projection 4c Straight tubular opening 4d Straight tubular opening 4e Tapered opening 4f Tapered opening 14 Elastic body 20 Solder 

Claims (6)

[Claims] 1. A disk-shaped piezoelectric ceramic is disposed on an inner surface of a bottom portion of a bottomed cylindrical vibration case, a lower surface of the piezoelectric ceramic is brought into contact with the vibration case, and a lead is erected on an upper surface of the piezoelectric ceramic. In the drip-proof ultrasonic microphone, which is surrounded by a ring-shaped ring silicon made of an elastic body, the outer periphery of which is fixed to the inner peripheral surface of the vibration case, it is in close contact with the exposed part of the lead drawn out of the piezoelectric ceramic A drip-proof ultrasonic microphone, wherein a projecting portion is provided continuously on the inner peripheral surface of the ring silicon. 2. The drip-proof type according to claim 1, wherein an exposed portion of the lead and a protruding portion which is in close contact with a solder for fixing the lead to the piezoelectric ceramic are provided continuously on the inner peripheral surface of the ring silicon. Ultrasonic microphone. 3. The ring-shaped silicon according to claim 2, wherein an exposed portion of the lead and a projecting portion covering the entire periphery of the solder for fixing the lead to the piezoelectric ceramic are provided continuously on the inner peripheral surface of the ring silicon. Drip-proof ultrasonic microphone. 4. A disk-shaped piezoelectric ceramic is disposed on the inner surface of the bottom of a bottomed cylindrical vibration case, the lower surface of the piezoelectric ceramic is brought into contact with the vibration case, and a lead is erected on the upper surface of the piezoelectric ceramic. In the drip-proof ultrasonic microphone, which is surrounded by a ring-shaped ring silicon formed of an elastic body, having an outer peripheral portion fixed to an inner peripheral surface of the vibration case, an exposed portion of a lead protruding above the piezoelectric ceramic is provided. A protruding portion covering the outer periphery of the solder for fixing the lead to the piezoelectric ceramic is continuously provided on the inner peripheral surface of the ring silicon, and the protruding portion has the lead as a central axis, and the solder for fixing the lead to the piezoelectric ceramic. Providing a straight tubular opening having a diameter slightly larger than the diameter of the lead, the exposed portion of the lead and solder for fixing the lead to the piezoelectric ceramics are inserted through the straight tubular opening, A drip-proof ultrasonic microphone characterized in that the straight tubular opening is filled with an elastic material having initial fluidity. 5. A disk-shaped piezoelectric ceramic is disposed on the bottom inner surface of a bottomed cylindrical vibration case, the lower surface of the piezoelectric ceramic is brought into contact with the vibration case, and a lead is erected on the upper surface of the piezoelectric ceramic. In the drip-proof ultrasonic microphone, which is surrounded by a ring-shaped ring silicon formed of an elastic body, having an outer peripheral portion fixed to an inner peripheral surface of the vibration case, an exposed portion of a lead protruding above the piezoelectric ceramic is provided. A projecting portion covering the outer periphery of the solder for fixing the lead to the piezoelectric ceramic is continuously provided on the inner peripheral surface of the ring silicon, and a straight tubular opening surrounding the solder for fixing the lead to the piezoelectric ceramic is provided on the projecting portion. And a tapered opening centered on the lead with the upper opening circle being larger than the lower opening circle at the upper portion thereof, and a piezoelectric ceramic is provided at the straight tubular opening portion. A solder for fixing the lead to the socket, and an exposed portion of the lead is inserted into the tapered opening, and an elastic material having initial fluidity is filled in the tapered opening. Type ultrasonic microphone. 6. A disk-shaped piezoelectric ceramic is disposed on an inner surface of a bottom of a cylindrical vibration case having a bottom, a lower surface of the piezoelectric ceramic is brought into contact with the vibration case, and a lead is erected on an upper surface of the piezoelectric ceramic. In the drip-proof ultrasonic microphone, which is surrounded by a ring-shaped ring silicon whose outer peripheral part is fixed to the inner peripheral surface of the vibration case, the exposed part of the lead projecting upward from the piezoelectric ceramic and the solder for fixing the lead to the piezoelectric ceramic A projecting portion that covers the outer periphery of the ring is provided continuously on the inner peripheral surface of the ring silicon, and the lead has a central axis at the projecting portion, and the diameter of the lower opening circle is the outer circumferential circle of the solder that fixes the lead to the piezoelectric ceramic. And a tapered opening whose upper opening circle is slightly larger than the lower opening circle is filled with an elastic body having initial fluidity in the tapered opening. A drip-proof ultrasonic microphone characterized in that: