JPH04212511A - Ultrasonic delay line - Google Patents

Abstract

PURPOSE:To almost completely exclude the influence of a sprious signal component by providing one hole in a prescribed shape at least on the main face of an ultrasonic delay medium. CONSTITUTION:On a transducer joining face 2 provided by notching one side face of a short ultrasonic delay medium 10 at 45 deg., an input transducer 4 and an output transducer 5 are respectively joined. Then, in the parts of main faces 50 and 50 excepting for regular signal paths, through holes 8, 8,... are provided and ultrasonic absorbing members 19 are applied to the inner peripheral faces of the respective through holes 8, 8,.... The holes 8, 8,... are shaped so as to obtain a reflection face parallel to the transducer joining face 2 in a downside semicircular part when drawing a parallel line on the transducer joining face 2 to the central point of the hole 8.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to improvements in ultrasonic delay lines.

0002

[Prior Art] The bulk wave type ultrasonic delay line that is currently widely used is a multi-reflection type ultrasonic delay line that uses a rectangular ultrasonic delay medium in order to obtain a relatively long delay time while being compact. Lines are the norm. The ultrasonic delay line 40 shown in FIG. 8 is a multi-reflection type ultrasonic delay line, and has a thickness of d
The main component is an ultrasonic delay medium 20 having a cutout surface (transducer adhesion surface) 2 with one side cut out at an angle of 45° along the center line.

On the transducer bonding surface 2, ground electrodes 3, 3 separated at the center are provided, and on top of the ground electrodes 4, an input transducer 4 and an output transducer 5 each having signal electrodes 14, 14 bonded to the upper surface are provided. Each electrode 3, 3, 14, 14 is connected to a lead wire 24, 24, 234, 34 using a conductive adhesive A, A, . . . , A, respectively, as shown in the figure. .

[0004] Also, the main surface 50 of this ultrasonic delay medium 20
, 50 are formed with cylindrical through holes 18, 18, . . . , 18 in order to remove spurious signals. is equipped with an ultrasonic absorber (
Epoxy resin containing silver (lead)) 19, 19, ..., 19 is applied.

On the other hand, ultrasonic absorbing materials 16, 16, . , 16 are applied.

[0006] The ultrasonic delay line 40 configured in this manner has side lobes other than the normal signal components of the ultrasonic signal propagating within the ultrasonic delay medium 20, the main surface 50 of the ultrasonic delay medium 20, 50, reflective side 60A, 60B, 60
Various spurious signal components (unnecessary signal components) generated due to the processing accuracy of C are diffusely reflected on the circumferential surfaces of the through holes 18, 18, ..., 18 and absorbed by the ultrasonic absorbers 19, 19, ..., 19, In addition, the spurious signal components are prevented from propagating to the output transducer 5 by absorbing them with the ultrasonic absorbing materials 16, 16, . . . , 16 on the side surfaces 60A, 60B, 60C.

[0007]

[Problem to be Solved] However, since the through holes 18, 18, . . . Spurious signal components are propagated,
In many cases, the influence of spurious signal components cannot be ignored, and this type of ultrasonic delay line 40 is used for high frequency, high quality VT.
When applied to a luminance/chrominance signal separation circuit of an R device, the image signal deteriorates, which is particularly problematic.

[0008]

OBJECTS OF THE INVENTION It is an object of the present invention to provide an ultrasonic delay line which can improve the disadvantages of the conventional example described above and can almost completely eliminate the influence of spurious signal components.

[0009]

[Means for Solving the Problems] Accordingly, in the present invention, one side of a rectangular ultrasonic delay medium is cut at 45 degrees to form a transducer joint surface, and input/output transducers are bonded to this transducer joint surface. , in an ultrasonic delay line comprising at least one circular hole in the thickness direction of the medium in a region other than the ultrasonic signal path on the main surface, the shape of the hole is aligned with the transducer joining surface with respect to the center point. The object is achieved by adopting a configuration in which a semicircular portion on the lower side when a parallel line is drawn has a reflecting surface parallel to the transducer joint surface.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. Here, the same reference numbers are given to the same constituent members as in the above-mentioned conventional example. The bulk wave type ultrasonic delay line 1 shown in FIG. 1 has a thickness d [mm] and a transducer adhesive surface 2 formed by notching one side at 45 degrees along the center line. A medium 10 is formed, and an input transducer 4 and an output transducer 5 are bonded on this transducer bonding surface 2, respectively.

On this transducer adhesive surface 2, grounding electrodes 3, 3 are formed separated at the center, and on each electrode 3, 3, an elliptical electrode 14, 14 is formed on the upper surface.
An input transducer 4 and an output transducer 5 are bonded together using a conductive adhesive (not shown). In addition, the grounding electrodes 3, 3 and the electrodes 14, 1
4, conductive adhesives A, A,
..., A are used to connect the lead wires 24, 24, 34, 34.

Further, through holes 8, 8, . Sound wave absorbing material (silver (lead))
epoxy resin) 19 is applied.

On the other hand, grooves 17, 17, .
is formed, and ultrasonic absorbing materials 16, 16,..., are formed inside it.
16 is applied.

The shape of the through holes 8, 8, . . . , 8 is similar to that of the main surface 5.
If a circle with a center point G is drawn in an area other than the regular signal path of 0.50, draw a line parallel to the transducer bonding surface 2 to the center point G, and draw a line parallel to the transducer bonding surface 2 in the lower semicircle. It has a shape with a reflective surface parallel to surface 2. According to this shape, the output transducer 5 side is a circumferential surface and becomes a diffusely reflecting surface, and the opposing surface reflects the incident spurious signal component at a predetermined angle, so that the spurious signal component is transmitted to the output transducer 5 side as a whole. can be made smaller than that of the conventional ultrasonic delay line 40 described above.

A method of manufacturing the ultrasonic delay line 1 constructed as described above will now be described with reference to FIGS. 2 to 7.

A. As shown in Figure 2, cut out the corner at 45° along the center line to form the notched surface (transducer adhesive surface).
A prismatic ultrasonic delay medium block 11 formed by forming 2
, and a delay medium block 1 adjacent to this cutout surface 2
A central portion 12 is provided on the top surface 1B and side surface 1C of 1 as shown in the figure.
Then, ground electrodes 3, 3 having non-electrode forming portions are formed.

B. The transducers 4, 5 are then glued with conductive adhesive on the electrodes 3, 3 of the transducer adhesive surface 2 of this delay medium block 11 with electrodes 29, 29 provided on their own lower surfaces 4A, 5A (not shown). Use to adhere. In this case, a plurality of elliptical electrodes 14, 14, . . . , 14 may be provided in advance on the upper surfaces 4A, 5A at predetermined intervals along the thickness direction of the delay medium block 11.

C. And as shown in FIG. 4, the side surface 60A
, 60B, 60C other than the regular signal reflection area,
Grooves 17, 17, ..., 17 of a predetermined depth are formed parallel to the thickness direction of the ultrasonic delay medium 10, and ultrasonic absorbing materials 16, 16, ..., 16 are applied inside the grooves (see FIG. 5). ). Note that the depth of the groove portion 17 is 1 [mm] or less, and is 0.3 mm.
~0.5 [mm] is sufficient.

D. Next, this delay medium block 11 is shown in FIG.
As shown in FIG.
3 [mm]) to produce a plurality of unfinished ultrasonic delay lines 11, 11, . . . , 11 at the same time.

E. Subsequently, each unfinished ultrasonic delay line 11,
Elliptical electrodes 14, 14 are provided on the transducers 4, 5 of 11, . . . , 11, respectively, as shown in FIG.
formed from one main surface 50 to the other main surface 50,
Holes 8, 8, ..., 8 with a bottom surface of depth D [mm] are provided, and an ultrasonic absorbing material (silver (lead)) is placed on the inner peripheral surface of each hole 8, 8, ..., 8
Apply epoxy resin 19.

F. Next, after connecting the lead wires 24, 24, 34, 34 on each electrode 3, 3, 14, 14 using conductive adhesive A, the time adjustment surface (side surface) 60A (Fig. 1) is polished. The delay time is finely adjusted and the excess portion of the ultrasonic absorbing material 16 is removed. Note that the ultrasonic absorbing material 16, 16, ..., 16 may be applied to each side surface 60A, 60B, 60C after the delay medium block 11 is individually cut with a cutter 9. The groove portion 17 may not be provided in the media block 11. Further, the holes 8, 8,..., 8 are formed on the main surface 50.
, 50 may be used.

[0022]

As the present invention is constructed as described above, it is possible to provide an ultrasonic delay line that can substantially completely eliminate the influence of spurious signal components.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of the manufacturing process of a bulk wave type ultrasonic delay line according to an embodiment of the present invention.

[Figure 8] Perspective view of conventional ultrasonic delay line

[Explanation of symbols]

1……Bulk wave type ultrasonic delay line 2...Transducer adhesive surface 3......Earth electrode 4……Input transducer 5……Output transducer 8……hole 10...Ultrasonic delay medium block 14...Signal electrode 16... Ultrasonic absorber 17...Groove 19...Ultrasonic absorbing material 24, 34...Lead wire A... Conductive adhesive

Claims (1)

[Claims] Claim 1: One side of a rectangular ultrasonic delay medium is set at 45°.
cut out to form a transducer bonding surface, adhere input and output transducers to this transducer bonding surface, and provide at least one circular hole in the thickness direction of the medium in an area other than the ultrasonic signal path on the main surface. The ultrasonic delay line provided has a reflecting surface parallel to the transducer joint surface in a lower semicircular portion when a line parallel to the transducer joint surface is drawn from the center point of the shape of the hole. An ultrasonic delay line characterized by a shape.