JP2002325299A - Method for manufacturing ultrasonic transmitting and receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bonding material from penetrating into voids in an acoustic matching member. SOLUTION: This device has a plurality of bonding means 4, 5, and 6 provided to bond a metal case 2 holding a vibrator 1 with an acoustic matching member 3 having a large number of voids. Among these bonding means 4, 5, and 6, the one adjacent to the acoustic matching member 3 bonds the acoustic matching member 3 and the other bonding means in a high viscosity state, which can prevent the bonding means from penetrating into the voids in the acoustic matching member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic transmitter / receiver used for an apparatus for measuring the flow rate or concentration of a gas or liquid using ultrasonic waves, an apparatus for measuring the distance to an object, and the like.

[0002]

2. Description of the Related Art FIG. 7 is a sectional structural view of a conventional ultrasonic transceiver. In the figure, a piezoelectric vibrator 1 made of ceramic is configured to vibrate at about 500 kHz.

[0003] A metal case 2 made of corrosion-resistant stainless steel protects the vibrator 1 from water and foreign substances, and prevents electric failure due to water intrusion, damage by foreign substances, and disturbance of vibration. There is.

[0004] A composite material of ceramic and glass is used as a material of the skeleton portion of the acoustic matching member 3 composed of a complicated skeleton portion and a large number of voids. Most of the gaps of the acoustic matching member 3 are connected to other gaps, and the acoustic matching member 3 has an open structure in which liquid easily permeates.

The role of the acoustic matching member 3 is to efficiently transmit the vibration (sound) of the vibrator 1 to substances such as gas, liquid, and solid. An ideal acoustic matching member 3 can be obtained from the following concept.

[0006] The acoustic impedance of a substance is determined by density x sound velocity. Air acoustic impedance Z _AIR is about 42
8kg / m ² s, the acoustic impedance Z _PZT piezoelectric vibrator is vibrator 1 is about ^{30 × 10 6 kg / m 2} s. When ultrasonic waves are radiated from the piezoelectric vibrator into the air, sound reflection occurs due to the difference in acoustic impedance between the two, and the efficiency of sound radiation into the air is reduced. What is used to improve this is an acoustic matching member. The acoustic impedance Z _M of an ideal acoustic matching member without sound reflection is

[0007]

(Equation 1)

[0008] Using the values of Z _PZT and Z _AIR above, Z _M is about 0.11 × 10 ⁶ kg / m ²
s. In order to obtain an acoustic matching member having such an ideal acoustic impedance, the material forming the acoustic matching member needs to have a low density and a low sound speed.

From the above, in the conventional acoustic matching member, a resin material having a low density is used, or a large number of gaps are provided, so that a configuration having a lower density is used.

An adhesive 4 using epoxy, which is one of the resin materials, bonds the metal case 2 and the acoustic matching member 3 together. The temperature at which the adhesive is solidified is about 100 ° C. or higher. Since the epoxy resin can be adhered and solidified at about room temperature to about 300 ° C., even if the thermal expansion coefficients of the metal case 2 and the acoustic matching member 3 are different, stress is generated on the bonding surface, and warping or peeling is rarely generated.

The electrode 7 is connected to one of the electrodes of the vibrator 1 via the metal case 2, and the electrode 8 is connected to the other electrode. The electrodes 7 and 8 serve as both an electric signal input terminal for vibrating the vibrator 1 and an output terminal for extracting an output signal of the vibrator 1. Reference numeral 9 denotes an insulating means, which is made of an electrically insulating material such as resin or glass, and insulates the electrode 8 from the metal case 2.

FIG. 8 illustrates a method of joining the metal case 2 and the acoustic matching member 3 in the method of manufacturing the ultrasonic transceiver shown in FIG. A weight 81 applies a load to the acoustic matching member 3. The weight of the weight 81 is preferably as long as it is within a range where the acoustic matching member 3 is not crushed. Further, a method of applying a load may be a spring.

The adhesive 71 is in the form of a paste.
This is because when the adhesive 4 is printed on the metal case 2 using the mesh screen, the printing is performed without variation. After printing on the metal case 2, the acoustic matching member 3 is placed, and a load is
The adhesive 71 is solidified by heating between 200 ° C., and the acoustic matching member 3 and the metal case 2 are joined. As described above, the acoustic matching member and the metal case are joined by heating and solidifying the paste adhesive.

[0014]

However, in the conventional method of manufacturing an ultrasonic transceiver using an adhesive, the liquid adhesive penetrates into the gap of the acoustic matching member by the action of surface tension, and the bonding area is reduced. Because of the decrease, the first problem is that the performance of the ultrasonic transceiver is deteriorated and that the acoustic matching member and the metal case cannot be bonded.

[0015] In addition, there is a second problem that the acoustic matching member peels off in an environment with a large temperature change due to a large coefficient of thermal expansion of the adhesive.

Further, in the above-mentioned adhesive, when the adhesive portion is exposed to corrosive gas or liquid, the resin material deteriorates and the bonding strength is weakened, and the acoustic matching member peels off. In the case of a gas containing water, there is a third problem that the epoxy absorbs water and the performance is reduced.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an ultrasonic transceiver having stable performance and small temperature characteristics of the performance.

[0018]

According to the present invention, a metal case for accommodating a vibrator is provided to solve the above-mentioned conventional problems.
A plurality of joining means for joining the acoustic matching member having a large number of voids, wherein the joining means of the first joining means which contacts the acoustic matching member has a large viscosity and the other joining means has a large viscosity. This is a method for manufacturing an ultrasonic transceiver for joining the two.

According to the present invention, since the viscosity of the first joining means is large, it is possible to prevent the first joining means from penetrating into the gap of the acoustic matching member during the joining, and it is also possible to prevent the first joining means from having a plurality of different thermal expansion coefficients. Since the joining means is provided, even if the acoustic matching member and the metal case have different coefficients of thermal expansion, stress caused by the difference in the coefficient of thermal expansion can be reduced, and the acoustic matching member and the metal case can be joined. Accordingly, bonding can be performed even at a high temperature where the influence of the difference in the coefficient of thermal expansion affects, an inorganic material having a high melting point can be used, and a highly reliable ultrasonic transceiver can be provided.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first aspect of the present invention comprises a metal case for accommodating a vibrator and a plurality of joining means for joining an acoustic matching member having a large number of voids. Of the joining means in contact with the acoustic matching member, the acoustic matching member and other joining means are joined in a state of high viscosity, so that even if the first joining means is melted, it penetrates into the gap of the acoustic matching member. Can be prevented,
It is possible to prevent the performance of the ultrasonic transceiver from deteriorating and to prevent the acoustic matching member from peeling off.

According to a second aspect of the present invention, in particular, by adjusting the viscosity of the first joining means according to the first aspect at a heating temperature, the first joining means penetrates into the gap of the acoustic matching member. And bonding can be performed at a low temperature where the influence of the coefficient of thermal expansion is small.

According to a third aspect of the present invention, in particular, the first joining means and the other joining means are joined at a first heating temperature, and thereafter, the acoustic matching member and the first joining means are joined. At the second heating temperature in the ultrasonic transceiver,
Since the first heating temperature is higher than the second heating temperature, the first bonding means is bonded to the other bonding means at a high temperature. The number of plate-like structures can be reduced. In addition, since the acoustic matching member and the first joining means are joined at a low temperature, joining can be performed in a state where the viscosity of the first joining means is high, and penetration of the acoustic matching member into the gap can be prevented. Even if the acoustic matching member and the first joining means have different coefficients of thermal expansion, they can be joined at a low temperature where the influence of the coefficient of thermal expansion is small. Peeling of the member can be prevented.

According to a fourth aspect of the present invention, the material of the first bonding means according to the second or third aspect is made of an amorphous glass. Since the amorphous glass can be melted again at a lower temperature, the acoustic matching member and the first joining means can be joined at a low temperature after joining the first joining means to the other joining means. In addition, since glass is used, an ultrasonic transceiver having stable temperature characteristics, high water resistance, and high corrosion resistance can be provided.

The invention described in claim 5 is particularly advantageous in claim 1 to claim 1.
The first joining means according to 4 is formed by heating the aggregate of particles, and the size of the particles is made larger than the size of the gap of the acoustic matching member, whereby the first joining means is melted. In the formation process, it can be prevented from penetrating into the gap of the acoustic matching member.

[0025] The invention described in claim 6 is particularly advantageous in claim 1 to claim 1.
Applying a load at the time of joining the acoustic matching member and the first joining means described in 5 to increase the joining area between the acoustic matching member and the first joining means even if the viscosity of the first joining means is high. Can be. In addition, it is possible to prevent the acoustic matching member from floating due to surface tension when the first joining means is melted.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of an ultrasonic transceiver according to Embodiment 1 of the present invention.

The piezoelectric vibrator 1 using a ceramic material is
It is hermetically sealed in a stainless steel case 2 that has corrosion resistance and high strength. The stainless steel of the metal case 2 has a coefficient of thermal expansion of 110 to 150 × 10 ⁻⁷ K ⁻¹ . By adopting a closed structure, intrusion of gas or water is prevented, and performance degradation and electrical failure of the vibrator 1 are prevented. The thickness of the metal case 2 is 200 to 300.
um and thin. By reducing the thickness of the metal case 2, the loss of sound (vibration) passing through the metal case 2 is reduced. In addition, by making the thickness of the metal case 2 sufficiently thin with respect to the sound wavelength of the metal case 2, the acoustic impedance of the metal case 2 can be theoretically ignored. The sound wavelength is derived from the operating frequency and sound speed of the object. This relational expression is shown in (Equation 2). Metal case 2
The speed of sound of stainless steel is 5000-6000m /
s and the operating frequency of the ultrasonic transceiver is 500 kHz, the sound wavelength of the metal case 2 is 10 to 12 according to (Equation 2).
mm. Therefore, the thickness of the metal case 2 is sufficiently thin with respect to the sound wavelength, and its acoustic impedance can be ignored.

Reference numeral 3 denotes an acoustic matching member. In this embodiment, a mixture of alumina and a glass material is used as the material. The thermal expansion coefficient of this mixture is 50 to 80 × 10 ⁻⁷ K ⁻¹ . The thermal expansion coefficient of the epoxy resin as the resin material is 400 to 500 ×
10 ⁻⁷ K ⁻¹ , which means that a material having an extremely low coefficient of thermal expansion is used. As described above, since a material having a low coefficient of thermal expansion is used, it is possible to produce an acoustic matching member having a stable performance that is not easily affected by a shape change due to an ambient temperature. The acoustic matching member 3 has a configuration having a large number of voids. This gap is mostly connected to another gap. Therefore, the structure is such that liquid such as water easily penetrates. The size of one space is 100 um or less. This magnitude is a value sufficiently smaller than the wavelength of the sound of the acoustic matching member 3, and has an effect of suppressing propagation loss of sound (vibration). Further, by providing a large number of air gaps, the bulk density of the acoustic matching member 3 is set to 0.6 g / cm ^3, and the sound propagation path is complicated by the air gaps.
00 m / s. The thickness of the acoustic matching member 3 is set to approximately １ ／ wavelength of the sound. The sound wavelength λ can be obtained by the following (Equation 2).

(Equation 2) λ = c / f (where c is the sound speed and f is the vibration frequency) (Equation 2) In the present embodiment, a 500 kHz sound is propagated, so the wavelength of the sound is 2.8 mm, which is a large difference with the gap size of 100 um. The quarter wavelength of the acoustic matching member 3 is 0.7
mm. As described above, the large number of voids provided in the acoustic matching member 3 can reduce the density and sound speed of the acoustic matching member 4 and reduce the acoustic impedance.

In FIG. 1, the plurality of joining means are composed of a first joining means 4, a second joining means 5, and a third joining means 6. The first joining means 4 is made of amorphous glass having a lower melting point than the mixture of alumina and glass used for the acoustic matching member 3. Amorphous glass has the following characteristics. The first feature is that melting starts at a temperature lower than the melting point. The second feature is that the viscosity varies depending on the temperature even in a molten state. The third feature is that it has reproducibility that it can be melted at a low temperature even after firing at a high temperature. In this embodiment, the joining is performed by adjusting the viscosity of the amorphous glass at the heating temperature so that the amorphous glass does not penetrate into the acoustic matching member 3. As this amorphous glass, one having a thermal expansion coefficient of 50 to 80 × 10 ⁻⁷ K ⁻¹ is used. This coefficient of thermal expansion is almost the same as that of the mixture of alumina and glass, which is the material of the acoustic matching member 3,
Even after the joining, the first joining means using the amorphous glass and the acoustic matching member 3 using the mixture of alumina and glass are not separated. Further, the thickness of the first joining means 4 is set to 100 to 200 μm. As in the case of the metal case 2, the thickness is such that the acoustic impedance of the first joining means 4 can be theoretically ignored.

The second joining means 5 is composed of a titanium oxide film having a thickness of several um. Since the amorphous glass used in the first bonding means 4 of the present embodiment is a kind of oxide glass, it can be bonded to oxygen of the titanium oxide film. The coefficient of thermal expansion of titanium, the source of titanium oxide, is
86 × 10 ⁻⁷ K ^−1, which is an intermediate value between the first joining means 4 and the third joining means 6. By setting the value to an intermediate value, there is an effect of gradually reducing the stress generated at the joint interface due to the difference in the coefficient of thermal expansion. In addition, titanium has malleability and can reduce the difference in the coefficient of thermal expansion even when objects having different coefficients of thermal expansion are joined.

The third joining means 6 is made of a silver braze, which is an alloy of silver and copper. One of the third joining means 6 is joined to the metal case 2 and the other is formed with an uneven shape. The coefficient of thermal expansion of silver braze is 1
80 × 10 ⁻⁷ K ⁻¹ , the thickness of the third joining means 6 is 10 to 1
00 um.

As described above, the plurality of bonding means have a structure in which the coefficient of thermal expansion is changed stepwise, and a part of the bonding means has an uneven shape. The first effect of the concavo-convex shape is that the bonding area can be increased, so that the bonding strength can be increased. The second effect is that the joining strength is increased because the joining means are engaged with each other. The third effect is that the stress due to the difference in the coefficient of thermal expansion applied to the joint interface is dispersed, and warpage or peeling is less likely to occur after joining. Reference numerals 7 and 8 denote electrodes for inputting electric power to the vibrator 1 and extracting the output of the vibrator 1. Reference numeral 9 denotes insulating means, which is made of glass, resin, or the like, and electrically insulates the electrode 8 from the metal case 2.

FIG. 2 is a sectional structural view of the ultrasonic transmitter / receiver when the first joining means 4 in FIG. 1 is joined in a state where the viscosity is small. 21 is a first joining means, the material of which is shown in FIG.
Similarly, amorphous glass is used. However, the heating temperature at the time of joining is higher by about 100 ° C. than that of FIG. 1, and the viscosity of the amorphous glass is reduced. 22
Is a void. Other configurations are the same as those in FIG. 1 and are omitted here.

As shown in FIG. 2, the first joining means 21 has partially penetrated into the gap of the acoustic matching member 3 due to the reduced viscosity. As a result of the permeation of a part of the first joining means 21, a void 22 is formed at the permeated portion. Void 2
2 is a size of 100 um or more, which is a size where the acoustic impedance of air cannot be ignored. Therefore,
The reflection of sound occurs between the air and the second joining means 5, so that sound (vibration) is hardly transmitted to the first joining means 21, and the performance of the ultrasonic transceiver deteriorates. When the gap 22 is further increased, the joining strength is greatly reduced, and the acoustic matching member is peeled off. Further, the degree of penetration of the first joining means 21 is not always constant. This variation in the degree of penetration causes variation in the performance of the ultrasonic transceiver.

However, in the ultrasonic transmitter / receiver shown in FIG. 1, since the first joining means 4 has a high viscosity and does not easily penetrate into the gaps, no gaps are formed in the first joining means 4. Therefore, there is no permeation variation,
It is possible to provide an ultrasonic transceiver that has stable performance.

In this embodiment, the titanium oxide film is provided in the second bonding means, but the present invention is not limited to this. When the first joining means is an oxide glass, the first joining means can be joined with an oxide. However, in this case, in order to reduce the stress due to the difference in the coefficient of thermal expansion from the silver brazing, it is necessary to take not only the uneven shape but also the intermittent shape, and to mix the silver brazing with a material having a small coefficient of thermal expansion. Becomes

(Embodiment 2) FIG. 3 is a flowchart showing a method of manufacturing the ultrasonic transceiver shown in FIG. FIG. 3 particularly shows a method of joining the metal case 2 and the acoustic matching member 3 by the first joining means 4, the second joining means 5, and the third joining means 6.

In the mixing process of step 31 in FIG. 3, a solid auxiliary comprising titanium particles as the material of the second bonding means 5, silver brazing particles as the material of the third bonding means 6, and a resin material is mixed with a predetermined amount. Mix in proportions. This solid auxiliary has viscosity. The viscosity makes the mixture easier to handle. That is, even if the mixture is applied to the metal case 2, the state can be maintained, and the application thickness of the mixture can be made constant by application using screen printing. Since this solid assistant is a resin material, it evaporates before melting the titanium or silver braze, which is the material of the joining means.

In the mixture application step of step 32, the mixture prepared in step 31 is applied to the metal case 2.
Specifically, screen printing is performed using a mesh printing tool. By adjusting the mesh shape of the printing tool, it is possible to adjust the coating thickness of the mixture and to adjust the uneven shape of the mixture after application.

In the mixture heating step 33, the metal case 2 coated with the mixture is heated in a vacuum furnace. 2
After evaporating the solid auxiliary agent at around 00 to 300 ° C., the mixture is further heated to a high temperature, and a third joining means composed of silver brazing is provided;
The second joining means is constituted by a titanium oxide film.

In the amorphous glass coating step of step 34, the metal case 2 on which the second bonding means 5 and the third bonding means 6 have already been formed is filled with the amorphous material, which is the material of the first bonding means 4. Apply glass. At this time, similarly to the mixing step 31, a mixture composed of the amorphous glass particles and the solid auxiliary is prepared so that the amorphous glass can be uniformly applied.
After applying the mixture of the amorphous glass particles and the solid auxiliaries, the mixture is dried to lose its fluidity. This prevents the mixture of the amorphous glass and the solid auxiliary from penetrating into the gap of the acoustic matching member 3.

In the acoustic matching member joining step of Step 35, the acoustic matching member 3 is placed on a mixture of amorphous glass and a solid auxiliary, and a load of several tens gf / cm ＾ 2 is applied thereto while applying a load of several tens gf / cm ＾ 2.
Heat around ~ 500 ° C. Heating takes place in air. As the amorphous glass particles melt, they join together to form a large plate. The viscosity of the amorphous glass at 400 to 500 ° C. is sufficiently large so that the amorphous glass does not penetrate into the gaps of the acoustic matching member 3 and is bonded to the glass or alumina of the acoustic matching member 3. Since this amorphous glass is an oxide glass, it is bonded to a titanium oxide film as the second bonding means 5. The temperature at which the glass of the acoustic matching member 3 begins to melt is 600
Since the temperature is not lower than ° C., the shape of the acoustic matching member 3 does not change during the joining.

In this embodiment, the mixture heating step 33 is performed.
Is heated at about 800 to 900 ° C. At this temperature, the third bonding means 6 can be formed by melting the silver brazing particles. Titanium has a melting point of 1650 ° C., but reacts with oxygen slightly present in the vacuum furnace to form a titanium oxide film. The reason why the titanium oxide film is formed on the surface of the third bonding means 6 made of silver brazing is that titanium reacts with oxygen on the surface of the third bonding means 6 made of silver brazing to diffuse. To do that.

In this embodiment, the size of the amorphous glass particles can be made larger than the size of the gap (100 um or less) in the acoustic matching member 3 in the amorphous glass coating step 34. In this case, even if the mixture of the amorphous glass particles and the solid auxiliary is not dried, the amorphous glass particles do not enter the voids of the acoustic matching member 3 and the acoustic matching member 3 Crystalline glass can be prevented from penetrating.

FIG. 4 shows the relationship between the viscosity of the amorphous glass, which is the material of the first bonding means 4, and the heating temperature. The viscosity of the amorphous glass at the first heating temperature T1 is N1. The viscosity of the amorphous glass at the second heating temperature T2 is N2. In FIG. 4, the first heating temperature T1 is higher than the second heating temperature T2, and the viscosity of the corresponding amorphous glass is smaller in N1 than in N2. That is, since the viscosity of the amorphous glass changes depending on the heating temperature, it is possible to adjust the heating temperature so that the viscosity does not penetrate into the gap of the acoustic matching member 3.

FIG. 5 is a cross-sectional structural view of the ultrasonic transmitter / receiver joined without applying a load in the acoustic matching member joining step 35. Reference numeral 51 denotes first bonding means, which uses amorphous glass as in FIG. Other configurations are the same as those in FIG. 1 and are omitted here.

As shown in FIG. 5, the first joining means 51 is concentrated and solidified, and the joining area with the acoustic matching member 3 is reduced. This is because the amorphous glass, which is the material of the first bonding means 51, is concentrated by surface tension and the weight of the acoustic matching member 3 having a low density due to its high viscosity is low. Cannot be deformed. However, if a load is applied to the acoustic matching member 3, the first joining means 51 can be crushed even if the viscosity is high, and the joining area can be increased. And since the viscosity is strong, the first joining means 51 can be joined almost without penetrating into the gap of the acoustic matching member 3.

(Embodiment 3) FIG. 6 is a flowchart showing a method of joining an acoustic matching member and a metal case different from FIG. Hereinafter, the joining method will be described with reference to FIG.
The steps from the mixing step 31 to the amorphous glass coating step 34 are the same as those in FIG.

Step 61 is an amorphous glass heating step.
The amorphous glass is heated at a first heating temperature T1. As shown in FIG. 4, since the viscosity of the amorphous glass is small at the first heating temperature T1, even if the amorphous glass is melted into one lump, it is crushed by gravity, and the second bonding means is formed. The first bonding means 4 is formed by bonding with the titanium oxide film 5. At the same time, since the viscosity of the amorphous glass is small, even if there is a gap inside the first bonding means 4 when forming the first bonding means 4, the gap is crushed by losing the surface tension of the amorphous glass. Therefore, a plate-like layer without voids can be formed.

Step 62 is an acoustic matching member joining step.
The acoustic matching member 3 is arranged on the first joining means 4 and several tens of
The acoustic matching member 3 is joined by heating at a second heating temperature T2 while applying a load of gf / cm ＾ 2. Second heating temperature T
The viscosity N2 of the amorphous glass in Example 2 is the first heating temperature T
1 is adjusted to a viscosity that is larger than the viscosity N1 of the amorphous glass and does not penetrate into the gaps of the acoustic matching member 3.

As described above, by heating the amorphous glass of the first bonding means 4 at a high temperature at which the viscosity can be reduced, a plate-like layer having no voids therein is formed, and the loss due to the voids is formed. The first joining means which does not cause the occurrence can be formed. Thereafter, the plate-like first joining means 4 and the acoustic matching member are heated and joined at a low temperature where the viscosity of the amorphous glass is large, so that the first joining means 4 does not penetrate into the gap of the acoustic matching member 3. Thus, the bonding area can be reliably ensured. At the same time, the acoustic matching member 3,
Since the joining can be performed at a low temperature where the shape change due to the heat of the metal case 2 is small, the concentration of stress due to the difference in the coefficient of thermal expansion can be reduced. When the joining of the acoustic matching member and the formation of the first joining means are performed simultaneously as in the first and second embodiments, the amorphous glass as the material of the first joining means is heated at a temperature having a high viscosity. Therefore, voids between the amorphous glass particles are likely to remain without being crushed. This gap can be crushed by increasing the load applied at the time of joining. However, it is necessary to apply a load of about 1 kgf / cm ＾ 2, which increases the size of the electric furnace to be joined and tends to increase the manufacturing cost. . However, as shown in FIG. 6, if the gap generated in the first joining means is eliminated first, the load applied at the time of joining can be reduced, and the electric furnace to be joined can be reduced in size.

In the first to third embodiments, the acoustic matching member is a mixture of alumina and glass. However, the acoustic matching member may be made of only alumina or only glass. It is not particularly limited as long as it is an aggregate of inorganic substances.

Further, the first joining means, the second joining means,
The third joining means is not limited to the first to third embodiments. The number of the joining means is not particularly limited as long as the difference in the coefficient of thermal expansion between the acoustic matching member and the metal case can be reduced. The material of the joining means may be an inorganic substance.

[0056]

As described above, according to the first to fifth aspects of the present invention, when a metal case accommodating a vibrator and an acoustic matching member having a large number of voids are joined, a high viscosity state is obtained. Therefore, it is possible to prevent the material of the joining means from penetrating into the gap of the acoustic matching member during joining, and to prevent the performance of the ultrasonic transceiver from being reduced.

According to the third aspect of the present invention, the gap between the first joining means is first eliminated, and then the acoustic matching member and the first joining means are joined. Loss of sound (vibration) can be reduced, and performance degradation of the ultrasonic transceiver can be prevented.

According to the sixth aspect of the present invention, since a load is applied at the time of joining, the joining area between the acoustic matching member and the first joining means can be increased, and the joining strength can be increased. Further, since the gap generated in the first joining means can be crushed, the loss of sound (vibration) in the first joining means can be reduced, and the performance of the ultrasonic transceiver can be prevented from deteriorating.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an ultrasonic transceiver according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration when joining fails in the receiver.

FIG. 3 is a flowchart illustrating a joining process of the acoustic matching member and the metal case according to the second embodiment of the present invention.

FIG. 4 is a characteristic diagram of the viscosity and heating temperature of the amorphous glass in the bonding step.

FIG. 5 is a cross-sectional view showing a configuration when a failure occurs in the joining step.

FIG. 6 is a flowchart illustrating a joining process of the acoustic matching member and the metal case according to the third embodiment of the present invention.

FIG. 7 is a sectional view showing the configuration of a conventional ultrasonic transceiver.

FIG. 8 is a sectional view showing a conventional method of joining an acoustic matching member and a metal case.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vibrator 2 metal case 3 acoustic matching member 4 first joining means 5 second joining means 6 third joining means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Nakabayashi 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture F-term (reference) 2F035 DA05 DA07 5D019 AA18 AA26 EE04 FF01 FF02 GG02 GG12 HH03 5J083 AA02 AC31 AD04 AD12 CA35 CA36 CA50 CB02

Claims (6)

[Claims] 1. A metal case for accommodating a vibrator, and a plurality of joining means for joining an acoustic matching member having a large number of voids, wherein the joining means of the plurality of joining means which is in contact with the acoustic matching member has viscosity. Manufacturing method of an ultrasonic transceiver for joining the acoustic matching member and other joining means in a state where the size is large. 2. The method for manufacturing an ultrasonic transceiver according to claim 1, wherein the viscosity of the first joining means is adjusted at a heating temperature. 3. An ultrasonic transceiver for joining a first joining means and another joining means at a first heating temperature and thereafter joining the acoustic matching member and the first joining means at a second heating temperature. 3. The method according to claim 2, wherein the first heating temperature is higher than the second heating temperature. 4. The method for manufacturing an ultrasonic transceiver according to claim 2, wherein the material of the first bonding means is amorphous glass. 5. The method according to claim 1, wherein the first joining means is formed by heating an aggregate of particles, and the size of the particles is larger than the size of the gap of the acoustic matching member. Manufacturing method of an ultrasonic transceiver. 6. The method of manufacturing an ultrasonic transceiver according to claim 1, wherein the acoustic matching member and the first joining means are joined by applying a load.