JPH05102784A - Ultrasonic wave delay line - Google Patents

Abstract

PURPOSE:To reduce a loss at a band of high frequencies by decreasing a load (capacitance) exerted onto a transducer. CONSTITUTION:An input transducer 4 and an output transducer 5 are provided respectively onto a transducer adhering face 2 of an ultrasonic wave delay medium 30 provided with the transducer adhesion face 2 formed by notching two side faces of a bulk wave type ultrasonic wave delay line 1 along a center line with a thickness of d(mm) at an angle of 35 deg.. Earth electrodes 9, 9 connected partly to an earth electrode 8 of each of the transducers 4, 5 are formed on the transducer adhering face 2, signal electrodes 7, 7 are formed to the upper face of each of the transducers 4, 5 and earth electrodes 8, 8 are formed to a lower face respectively and lead wires 25, 25,..., 25 are connected to the signal electrodes 7, 7 and the earth electrodes 9, 9 by using a conductive adhesives A. In this case, the conductive adhesives A is coated to the end of the earth electrodes 9, 9 especially so that the adhesives A reaches the transducer adhesion face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a bulk wave type ultrasonic delay line.

[0002]

2. Description of the Related Art A bulk wave type ultrasonic delay line, which is widely used at present, is a small-sized and multi-reflection ultrasonic wave using a rectangular ultrasonic delay medium in order to obtain a relatively long delay time. Delay lines are the mainstream.

Reference numeral 10 shown in FIG. 7 is a multi-reflection ultrasonic delay line, which has a thickness of d [mm] and is formed by cutting out two side faces at 35 ° along the center line. 2. The ground electrodes 12, 12 are provided on the transducer bonding surface 2 of the ultrasonic delay medium 30 provided with 2, and the transducers 14, 14 having the signal electrodes 16, 16 formed on the upper surfaces thereof are bonded to the ground electrodes 12, 12, respectively. Ground electrode 1
, 12 and the signal electrodes 16 and 16 using the conductive adhesive (solder) A, the lead wires 25, 25 ,.
The connection is made as shown in (FIG. 9). The ultrasonic delay line 10 vibrates in a specific region of the transducer 14, that is, the overlapping region B of the signal electrode 16 and the ground electrode 12 shown in FIG.
The ultrasonic beam C is output to.

Generally, the ultrasonic delay line 10 needs to reduce the influence of spurious signals, especially 3τ spurious signals, when actually propagating the signals. In order to reduce the influence of this 3τ spurious signal (which is not required to be converted into an electric signal by the output side transducer 14), specifically, the impedance Z (capacity) of the transducer 14 needs to be adjusted.

However, as shown in FIG. 9, the area of the signal electrode 16 is small, and there is no place for adjusting the impedance (adjusting by scraping the electrode surface), which is practically impossible. However, there is an inconvenience that the influence due to cannot be removed.

Therefore, the inventor has previously invented and applied for an ultrasonic delay line having a configuration that solves this problem (Japanese Patent Application No. 2).
-319619). As shown in FIG. 5, this ultrasonic wave delay line 11 is an ultrasonic wave delay line having a transducer bonding surface 2 formed by cutting out two side surfaces at a thickness of d [mm] along the center line at 35 °. An input transducer 4 and an output transducer 5 are provided on the transducer bonding surface 2 of the medium 30, respectively.

Ground electrodes 19, 19 are formed on the transducer bonding surface 2, and each of the transducers 4, 5 has a signal electrode 7, 7 on the upper surface and a ground electrode 8, on the lower surface. 8 are formed, and the lead wires 25, 25, ..., 25 are connected to the signal electrodes 7, 7 and the ground electrodes 8, 8 by using the conductive adhesive A (see FIG. 6). Then, on the transducer bonding surfaces 2 and 2, the ground electrodes 19
9 is formed, and a non-electrode forming region 22 is provided on one end of the upper surface of the transducer 5 on which the signal electrode 7 is formed.
Is formed, and the ground electrode 8 is formed on the lower surface by providing the non-electrode forming area 23 at one end which does not face the non-electrode forming area 22 on the upper surface. In this case, the vibrating portions of the transducers 4 and 5 are located in the area D in FIG.
And the ground electrode 8 overlap. The lead wires 25, 25, 25, 25 are connected to the ultrasonic signal using conductive adhesives A, A, ..., A as shown in the figure.

Here, a method of adjusting the impedance Z of each transducer 4 and 5 will be described. In FIG.
A region 15 on the upper surfaces of the transducers 4 and 5 serves as an adjustment region of the impedance Z, and the capacitance can be reduced by appropriately cutting this region, and the area of the vibrating portion D can be reduced, thereby reducing the influence of the 3τ spurious signal. To do. Further, as shown in the figure, the area of the signal electrode 7 of the transducers 4 and 5 can be made wider than that of the ultrasonic delay line shown in FIG. 8, so that the lead wire 25 can be easily connected.

[0009]

However, in the case of the conventional example shown in FIG. 5, the impedance Z of each transducer 4, 5 can be adjusted, but the center frequency 90 ± 30 [MHZ] required by the user. In Fig. 11 (a), the characteristics of "-3 [dB]" at the peak of the insertion loss cannot be satisfied, and as shown in FIG.
However, there was an inconvenience that it became "3 [dB]". Therefore, when manufacturing such a wide band ultrasonic delay line, there is a disadvantage that it is difficult to adjust the impedance of the transducer and the yield is poor and the production efficiency is reduced.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic delay line capable of improving the disadvantages of the above conventional example, reducing the load (capacity) of the transducer, and reducing the loss in the high frequency band. To aim.

[0011]

SUMMARY OF THE INVENTION In the present invention, therefore, a ground electrode is provided on a transducer bonding surface of a polygonal ultrasonic delay medium, and a ground electrode is provided on the upper surface of the polygonal ultrasonic delay medium at least at an end portion of the upper surface facing the ground electrode. A transducer including a signal electrode having an electrode forming region is joined, one lead wire is connected to the ground electrode, and the signal electrode is included at the end of the signal electrode opposite to the ground electrode. The present invention aims to achieve the above-mentioned object by adopting a configuration in which a conductive member reaching the adhesive surface is applied and the other lead wire is connected.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, the same components as those in the above-mentioned conventional example are designated by the same reference numerals.

A bulk wave type ultrasonic delay line 1 shown in FIG.
Has a thickness d [mm] of 35 ° on the two sides along the center line.
The ultrasonic transducer medium 30 is provided with the transducer adhering surface 2 formed by cutting it out, and the input transducer 4 and the output transducer 5 are respectively provided on the transducer adhering surface 2 of the ultrasonic delay medium 30.

Grounding electrodes 9 and 9 are formed on the transducer bonding surface 2, and the signal electrodes 7 and 9 are formed on the upper surfaces of the transducers 4 and 5, respectively.
7, ground electrodes 8, 8 are formed on the lower surface, and lead wires 25, 25, ..., 25 are connected to the signal electrodes 7, 7 and the ground electrodes 9, 9 using a conductive adhesive A. ing.

The ground electrodes 9 and 9 provided on the transducer bonding surfaces 2 and 2 are constructed so as to be partially connected to the ground electrodes 8 of the respective transducers 4 and 5. Then, a non-electrode forming region 22 is provided on one end of the upper surface of the transducer 4 (5) to form a signal electrode 7, and a non-electrode is formed on one end of the lower face not facing the non-electrode forming region 22 of the upper surface. The formation area 23 is provided to provide the ground electrode 8
Are formed. The non-electrode forming region 23 is a very important portion in the present invention, and this portion is made wide to some extent, the conductive adhesive A is applied from the end portion of the signal electrode 7 to the transducer bonding surface 2, and the lead wire 25 is formed. When connected, it is necessary to prevent the conductive adhesive A from contacting the ground electrodes 8 and 9.

In this case, the vibrating portion of each of the transducers 4 and 5 is the area D in the figure, that is, the overlapping portion of the signal electrode 7 and the ground electrode 8. .., 25 are connected using conductive adhesives A, A, ..., A as shown in FIG.

Here, a method of adjusting the impedance Z of each transducer 4, 5 will be described. In FIG.
A region 15 on the upper surfaces of the transducers 4 and 5 serves as an adjustment region of the impedance Z, and the capacitance can be reduced by appropriately cutting this region, and the area of the vibrating portion D can be reduced, thereby reducing the influence of the 3τ spurious signal. To do. Also, the signal electrodes 7, 7 of the transducers 4, 5 are
In connecting the lead wire 25 to the lead wire 25, the amount of the conductive adhesive A on the signal electrode 7 can be reduced, so that the load applied to the transducers 4 and 5 can be reduced, and as a result of the experiment, the loss on the high frequency side can be reduced. .. That is, as a result, as shown in FIG. 11B, at the insertion frequency peak at the center frequency 90 ± 30 [MHZ] required by the user, “−”
It became possible to easily satisfy the characteristic of "3 [dB]". Furthermore, since the load on the transducers 4 and 5 can be reduced, it is possible to easily manufacture an ultrasonic delay line that satisfies the characteristics as compared with the conventional example, and the production efficiency is improved.

[0018]

Since the present invention is configured as described above, it is possible to provide an ultrasonic delay line which can reduce the load (capacitance) related to the transducer and reduce the loss in the high frequency band.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ultrasonic delay line according to an embodiment of the present invention.

FIG. 2 is a partially enlarged explanatory view showing a part of FIG.

FIG. 3 is an assembly explanatory view of the ultrasonic delay line shown in FIG.

FIG. 4 is an assembly explanatory view of the ultrasonic delay line shown in FIG.

FIG. 5 is a configuration diagram of an ultrasonic delay line according to a conventional example.

6 is a partially enlarged explanatory view showing a part of FIG.

FIG. 7 is an assembly explanatory view of an ultrasonic delay line of a conventional example.

FIG. 8 is an assembly explanatory diagram of an ultrasonic delay line of a conventional example.

FIG. 9 is a partially enlarged explanatory view showing a part of an ultrasonic delay line of a conventional example.

FIG. 10 is a partially enlarged explanatory view showing a part of an ultrasonic delay line of a conventional example.

FIG. 11 is a diagram showing band characteristics of an ultrasonic delay line according to a conventional example and the present invention.

[Explanation of symbols]

 1 ………… Bulk wave type ultrasonic delay line 2 ………… Transducer adhesive surface 4 ………… Input transducer 5 ………… Output transducer 7 ………… Signal electrode 8, 9… Ground electrode 22 …… Non-electrode forming area 25: Lead wire A: Conductive member

Claims (1)

[Claims] 1. A ground electrode is provided on a transducer bonding surface of a polygonal ultrasonic delay medium, and a signal electrode having a non-electrode forming region is provided on an upper surface of the polygonal ultrasonic delay medium at least at an end side of the upper surface facing the ground electrode. A transducer formed by joining the two electrodes to each other, connecting one lead wire to the ground electrode, and at the end of the signal electrode opposite to the ground electrode, a conductive member including the signal electrode and reaching the transducer bonding surface. An ultrasonic delay line characterized by being applied and connecting the other lead wire.