JPS5917716A - Ultrasonic delay line - Google Patents

Abstract

PURPOSE:To make a delay medium small-sized and reduce the production cost, by sticking a pair of transducers to both ends of the hexahedral delay medium, where faces opposing each other are parallel with each other and adjacent faces form right angles, so that these transducers do not oppose each other. CONSTITUTION:Metallic electrodes 12a and 12b are formed in both end parts of a delay medium 11 which consists of glass, metals, ceramic, or the like and is formed to a hexahedron where faces opposing each other are parallel with each other and adjacent faces form right angles. A pair of transducers 13 and 14 for input and output are stuck onto these electrodes so that transducers 13 and 14 do not oppose each other. Metallic electrodes 15 and 16 are formed on these transducers 13 and 14, and lead wires 18 and 19 for input and output are attached to surfaces of electrodes 15 and 16, and lead wires 17a and 17b for earth are attached to metallic electrodes 12a and 12b. Ultrasonic waves excited by the transducer 13 for input are propagated in a propagation path 21 while being reflected plural times in the delay medium 11 and reach the output transducer 14.

Description

[Detailed description of the invention] Industrial applications The present invention relates to ultrasonic delay lines.

The ultrasonic delay line is an electronic component used in the signal processing circuit of video equipment such as color 'I' V and VTR, and has the function of delaying the video signal by about 1 horizontal cycle period (about 641 Asec). It is used in circuits such as separation, cross color removal, and dropout compensation.

The structure of the conventional example and its problems By the way, one conventional ultrasonic delay line had a structure as shown in FIG. 1. That is, (1) is a delay medium for ultrasonic propagation made of a material such as glass, and (2) is a metal electrode formed on this delay medium by a method such as vapor deposition. is transducer t3H
41 is fixed by a method such as soldering or gluing. Metal electrodes <51 (6) are formed on the surfaces of these transducers +31 (41) by a method such as vapor deposition.
Input and output lead wires (71 (8) (9) are attached using solder, conductive adhesive, etc.), and an input signal voltage is applied between the metal electrodes (2) (5). Then, the transducer (3) vibrates, and ultrasonic vibrations are excited in the vertical direction from the center of the transducer, propagate through the path 00 inside the delay medium (1), and are transmitted to the transducer (4). This is reached and excited, and the output voltage is taken out between the metal electrodes (2+(61).

Here, the length of the path QI is set to 1. If the speed of sound in the delay medium (1) is υ, then the delay time, that is, the ultrasonic wave from the first transducer (3) to the second transducer (
The time required to reach 4) is expressed as τ=reduction. Currently commonly used delay media (
1) The speed of sound ν is approximately 2.55 km/sec, so to obtain a delay time t of 64 Bsec, approximately 162 m is required.
A path length l of length m is required. Therefore, conventionally the first
As shown in the figure, two corners of the delay medium (1) are notched at 45 degrees to form a slope, and the first and second transducers (3) and (4) are installed on this slope, and the delay medium (1) is Medium (
1) A small ultrasonic delay line is created by reflecting the ultrasonic wave internally at a reflection angle of 45 degrees to form a bent path 0( ).

In this way, in conventional ultrasonic delay lines, a polygonal structure having one or more hypotenuses with corners cut out at 45° is often used, and the delay medium (1) is designed to increase the number of reflections of ultrasonic waves.
By devising the shape and dimensions of the delay medium (1)
It is possible to further downsize. However, if miniaturization is promoted in this manner, a problem arises in that the hypotenuse becomes too small, and the dimensions of the transducer must be significantly reduced. When the transducer becomes smaller, the efficiency decreases significantly and the directivity of ultrasonic waves decreases, so that the performance against insertion loss and unnecessary reflection noise, which is the basic performance of an ultrasonic delay line, deteriorates.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate such problems and provide an ultrasonic delay line that is ultra-small and inexpensive to manufacture.

Structure of the Invention For this reason, the present invention provides at both ends of a delay medium made of a material such as glass, metal, or ceramic, and formed into a hexahedron with opposing surfaces parallel to each other and adjacent surfaces forming right angles.
By attaching a pair of transducers so that they do not face each other, the ultrasonic wave propagates from one end of the delay medium to the other while making use of the spread of the ultrasonic wave to perform an extremely large number of reflections. Provides a sonic delay line. The pair of transducers may be mounted at opposite ends of one long side, or may be mounted at spaced apart ends of two long sides, or one end of one long side and one end of the long side. It can be attached in one of three ways: attached to the short side adjacent to the other end;

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings. In the first embodiment shown in FIG. 2, Q]) is a delay medium for ultrasonic propagation made of glass, metal, ceramic, etc., and is formed into a hexahedron in which opposing surfaces are parallel to each other and adjacent surfaces are at right angles. has been done. In the illustrated example, the front shape is a thin rectangular parallelepiped with a large aspect ratio, and metal molds i (12a) (12b) are formed at both ends of one long side of the rectangle. The transducer (to) and the output transducer (141) are fixed. On top of the transducer 03 Q41 is a metal electrode (to) aQ.
are formed, and these metal electrodes (on the surface number of 46QfG are lead wires for input and output, respectively).
Grounding lead wires (17a) (17b) are attached to the metal electrodes ('12a) (12b).

In such a configuration, the ultrasonic wave excited by the input transducer a3 propagates along the propagation path Qυ while being reflected many times within the delay medium 0υ as shown in bl, and reaches the output transducer 04). .

The second embodiment shown in FIG.
; and the output transducer (14+ is the delay medium 0υ
It differs from the first embodiment only in that it is attached to ends spaced apart from each other on two long sides, and substantially the same components will be described with the same reference numerals. omitted.

Even in such a configuration, as shown in FIG. This is reached.

The third embodiment shown in FIG.
3 is attached to one end of one long side of the delay medium OD, and the output transducer α4) is attached to the short side adjacent to the other end of the long side. The only difference is that substantially the same components are given the same reference numerals and their description will be omitted.

In this embodiment as well, as shown in FIG. 4(b), the ultrasonic waves excited by the input transuser 03 are
It propagates along the propagation path @ while being reflected many times within the delay medium αυ, and reaches the output transducer 0 (a).

In this third embodiment, the input transducer α3 and the output transducer α4) are opposite to each other, that is, the output transducer α4) is placed at one end of the long side.
An input transducer may be placed on the short side.

Effects of the Invention According to the ultrasonic delay line of the present invention, as is clear from the above explanation, the delay medium is formed into a hexahedron shape, and there is no need to form a hypotenuse, so the processing of the delay medium is easy. In addition, since it is sufficient to attach one or two transducers to each long side, or one transducer to each long side and one short side, the size of the transducer is not limited, and therefore the delay medium can be downsized. It is possible to realize an ultra-small ultrasonic delay line with low insertion resistance.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional ultrasonic delay line, and Figures 2 to 4 are
The figures each show an embodiment of the present invention, each (al is a perspective view, (bl is a front view. 0]) is a delay medium, (12a) (12b) lJ5cIe
is electrode, 0■04) Ha transducer, (17a) (
17b) (laQ! is the lead wire, 2+)@(c) is the propagation path. Figure 4(a) 18 314

Claims (1)

[Claims] (1) A delay medium made of a material such as glass, metal, or ceramic, and formed into a hexahedron in which opposing surfaces are parallel to each other and adjacent surfaces are at right angles; an ultrasonic delay line with a pair of transducers affixed to prevent