JPS6218812A - Ultrasonic solid delay line - Google Patents

Abstract

PURPOSE:To form an inexpensive ultrasonic solid delay line which is easily manufactured and has an extremely high center frequency by forming polygonal multiple reflecting surfaces on an ultrasonic solid delay medium, arranging an input and an output transducer on the reflecting surface, and diffusing and reflecting the spuriousness of a longitudinal wave on a main boundary surface. CONSTITUTION:Hexagonal multiple reflecting surfaces 2-7 are formed on the ultrasonic solid delay medium 1 like glass; and an output transducer 10 which radiates a longitudinal wave 8 are arranged on the reflecting surfaces 2 and 4 and an output transducer 11 which receives the longitudinal wave on other reflecting surfaces 5 and 7 are arranged on the other reflecting surfaces 5 and 7. Further, the width of the input and output transducers 10 and 11 is as large as the thickness of the ultrasonic solid delay medium and the transducers cross main boundary surfaces 12 and 13 at right angles. Therefore, the input and output transducers 10 and 11 have a function of neither transmitting nor receiving mode waves other than a 0 mode substantially, so the constitution of a nondispersive mode delay line is simplified.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an ultrasonic solid-state delay line, particularly an ultrasonic solid-state delay line having an extremely high center frequency, for example 100 MHz, which has good characteristics, is easy to manufacture, and has a low cost. It is concerned with high-frequency ultrasonic solid-state delay lines.

[Technical Background of the Invention] Low-frequency ultrasonic solid-state delay lines have been known (
Japanese Patent Publication No. 47-27574, Japanese Patent Publication No. 46-22818, USP 3,581,247). □These low-frequency ultrasonic solid-state delay lines form polygonal multiple reflection surfaces, and as shown in FIG. A transverse bulk wave is used, and the spurious is absorbed or diffusely reflected by an absorbing material or a diffused reflection surface 36.37 provided on the main boundary surface 34.35 orthogonal to the reflecting surface.

Nowadays, for example, high-definition televisions require ultrasonic solid-state delay lines with an extremely high center frequency of, for example, 100M1iz.

For this reason, using the same transverse bulk wave, the thickness t of the delay medium M is adjusted to the extent that the sidelobes and other spread waves 38 do not separate and become spurious as shown in FIG. 8, and the output transducer 32.33 It was thicker than that.

[Problems with Background Art] As shown in FIGS. 7 and 8, such an ultrasonic solid state delay line tends to generate spurious signals due to the portion 39 of the delay medium M, which is thicker than the person and the output transducer 32, 33. The wave incident on the main boundary surface of the delay medium has a large angle of incidence, so even if an absorbing material is attached as shown in Figure 7, the absorption effect is weak and it is easy to be reflected. There is a drawback that the cost I. is high because it is manufactured in batches.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional difficulties. It is intended to provide an ultrasonic solid state delay line.

. [Summary of the Invention] In order to achieve such an object, according to the ultrasonic solid-state delay line of the present invention, a polygonal multiple reflection surface is formed in the ultrasonic solid-state delay medium, and a part of the reflection surface has longitudinal An input transducer emits a wave and the longitudinal wave is reflected at another reflective surface.
an output transducer that receives longitudinal waves that have been subjected to transverse wave conversion and transverse wave-longitudinal wave conversion; An ultrasonic diffused reflection area is provided at the main boundary surface to cause diffused reflection.

[Embodiments of the invention] Preferred embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the ultrasonic solid-state delay line of the present invention has hexagonal multiple reflection surfaces 2 to 7 formed on an ultrasonic solid-state delay medium 1 such as glass. Part 2.4
, an input transducer 10 emits a longitudinal wave 8 (shown in dotted line) and said longitudinal wave is reflected at another reflecting surface 5.7.
An output transducer 11 is arranged to receive a transverse wave 9 (indicated by a solid line) conversion and a transverse-longitudinal converted longitudinal wave. In the illustrated example, the multiple reflection surfaces 2 to 7 are formed in a pentagonal shape, but they can be formed in other polygonal shapes depending on the amount of delay of the delay line.

Two parallel main boundary surfaces 12.1 orthogonal to reflective surfaces 2-7
Ultrasonic diffuse reflection region 14.3, which diffusely reflects longitudinal wave spurious waves 16 (FIGS. 3 and 4) radiated from the input transducer 10 at the main boundary surface 12.13, is formed on at least a part of, in the illustrated example, almost the entire surface of, ultrasonic wave diffused reflection region 14.3. 15 are provided.

The input transducer 10 and the output transducer 11 have the same width as the thickness of the ultrasonic solid delay medium (denoted by 1).
and is perpendicular to the main boundary surface 12.13 (indicated by lR). However, the electrode (not shown) of the transducer 10 does not need to have the same width (t, ) as the thickness of the ultrasonic optical medium l.

The surface roughness of the main boundary surfaces 12 and 13 is λ/20 to λ15 at the wavelength of the propagating ultrasound. When the width of the image is finer than λ/20 of the wavelength λ of the propagating ultrasonic wave, and when it is coarser than λ/5, the desired diffused reflection will not occur, and both are unfavorable.

According to the ultrasonic solid-state delay line configured in this way, the longitudinal wave 8 radiated from the input transducer 10 disposed on the reflecting surface 2 of the ultrasonic solid-state delay medium 1 at an angle of 90° to that surface is reflected in the delay medium 1. will be propagated.

This longitudinal wave is converted into a longitudinal wave and a transverse wave at the reflecting surface 5 of the pond, and is bent as a transverse wave 9 and propagates to another reflecting surface 6.

This situation will be explained with reference to FIG.

When a longitudinal wave 8 is incident on the interface 5 between the solid medium (2) and the fluid medium (2) at an angle α, a transverse wave 9 also appears in the reflected wave 8a. The reflection angle α of longitudinal waves is equal to the incidence angle α, but the reflection angle β of transverse waves is different. The relationship between the reflection angles in these reflections is 5ina/Sinβ=Cpl/Csl. Note that Cpl is the propagation velocity of longitudinal waves in medium I, Cs
l is the propagation velocity of the transverse wave in the medium (2).

The ratio of the amplitudes of the incident longitudinal wave 8 and the reflected longitudinal wave 8a depends on the incident angle α using the Poisson's ratio of the medium I as a parameter, and there is an incident angle at which the amplitude of the reflected longitudinal wave 8a becomes 0 (zero). At the angle of incidence where the amplitude of the reflected longitudinal wave 8a becomes 0, the incident longitudinal wave 8a
is completely converted into a transverse wave 9. For example, when the medium I is quartz glass with a Poisson's ratio of about 0°14 and the fluid medium 2 is air, the incident angle α is about 45°, the amplitude of the reflected longitudinal wave 8a is O, and the incident longitudinal wave 8 is completely a transverse wave. A conversion to 9 occurs.

The reflection angle β of this transverse wave 9 is about 30''. The reflection angle α of the longitudinal wave and the reflection angle β of the transverse wave in FIG. 1 correspond to those in FIG.

This transverse wave undergoes total reflection of the transverse wave-transverse wave at the reflecting surface 6, and at another reflecting surface 7, the longitudinal wave which has been converted into a transverse wave-longitudinal wave, which is the opposite of the above conversion, is reflected by the reflecting surface of the ultrasonic solid delay medium 1. Output transducer 11 located at 4 and 9 on its face
It is incident at 0''.

As mentioned above, in the ultrasonic solid-state delay line according to the present invention, the input transducer 10 and the output transducer 11 have the same width (t.) as the thickness of the ultrasonic solid-state delay medium, so that the output transducer 10.1 is in zero mode. Since the non-dispersive mode delay line substantially has the function of not transmitting or receiving any other moat waves, it is easy to configure a non-dispersive mode delay line. However, as shown in Figure 3, most of the main boundary surfaces 12.13
A wave nearly parallel to is generated, resulting in a spurious signal 16. In the prior art, this spurious was prevented by the configuration shown in FIGS. 7 and 8 as described above, but in the present invention, the main interface 1
2.13, in the illustrated example almost the entire surface,
Since the ultrasonic diffuse reflection region 14.15 is provided, at least one of the spurious waves 16 of the longitudinal wave 8 emitted from the input transducer 10 and incident at an angle close to parallel to the main boundary surface 12.13 is reduced as explained in FIG. Since the ultrasonic wave is converted into a longitudinal wave-transverse wave moat or longitudinal wave-longitudinal wave converted and diffusely reflected as a transverse wave or longitudinal wave (representatively indicated by 17 in FIG. It expires at .15 and is removed. Furthermore, if an ultrasonic absorbing material such as epoxy resin is bonded onto the ultrasonic diffuse reflection region 14.15 of the main boundary surface 12.13, this spurious wave will be absorbed at the main boundary surface 12.13, and the spurious wave removal effect will be improved. will improve.

In addition, since the input transducer 10 and the output transducer 11 are orthogonal to the two parallel principal term n-planes 12.13, the rectilinear wave radiated from the input transducer 10 travels straight between the principal boundary surfaces 12.13 and is output. incident on the transducer 11.

In manufacturing such an ultrasonic solid delay line,
As shown in FIG. 6, a block 40 of the ultrasonic solid retardation medium 1 is prepared, on which polygonal multiple reflection surfaces 2 to 7 (FIG. 1) of pre-designed dimensions are formed. Part of the reflective surface 2.4
Tin electrodes 41 and 42 are attached by vapor deposition. Above this, an input transducer strip 43 and a transducer strip 44 are placed. In this state, the delay time is measured and the reflective surface 6 is polished by the required amount (main adjustment).

This is cut by a slurring machine to obtain each unit 45 having an input transducer 10 and an output transducer 11. At this time, the delay time is measured, and if necessary, a reflective surface 6 is placed in parallel (fine adjustment M). The main boundary surface of each unit 45 is roughened to form an ultrasonic diffused reflection area 36.3.
7 (Figure 4).

According to this manufacturing technique, an input transducer strip and an output transducer strip are provided in a block of ultrasonic solid delay medium formed with a polygonal multi-reflection surface of a pre-designed geometry, and the delay time is adjusted. After that, the whole is cut into units, so that the delay times of the obtained units will not be uneven, and a high-quality 1B sonic solid-state delay line can be obtained. Additionally, since the input and output transducers are cut to have the same width as the thickness of the ultrasonic solid delay medium, it is easy to construct a non-dispersive mode delay line.

[Effects of the Invention] As is clear from the above embodiments, according to the present invention, polygonal multiple reflection surfaces are formed in the ultrasonic solid delay medium, so that the longitudinal waves radiated from the input transducer are divided into longitudinal waves and transverse waves. converting and transverse wave-longitudinal wave conversion to be incident on the output transducer, and at least a portion of the main interface perpendicular to the reflecting surface, the spurious of the longitudinal wave radiated from the input transducer is at the main interface. Since we have provided an ultrasonic diffused reflection area, it can completely absorb spread waves such as side lobes, and only straight waves can be used.It has good characteristics and has an extremely high center frequency, for example 100M)lz.
A high-frequency, non-dispersive ultrasonic solid-state delay line of approximately 100% is obtained.

In general, the thickness of the ultrasonic solid retardation medium can be reduced and material is saved. Also, an ultrasonic solid state delay line that is easy to manufacture and of high quality is provided.

[Brief explanation of drawings]

FIG. 1 is a plan view of an ultrasonic solid state delay line according to the present invention, and FIG.
The figure is a side view of the delay line, Figure 3 is a side view of the delay line before completion, Figure 4 is a side view of the delay line after completion, Figure 5 is an explanatory diagram of the operation of the delay line, and Figure 5 is a side view of the delay line before completion. FIG. 6 is an explanatory diagram when manufacturing the same delay line, and FIGS. 7 and 8 are side views of the conventional delay line. 1-...Ultrasonic solid delay medium 2-7...Multiple reflection surface 8...Longitudinal wave 9...Transverse wave 10...Input transducer 11...Output transducer 12.13...Main interface 14.15... Ultrasonic diffused reflection area 16... Spurious

Claims (1)

[Claims] 1. An input transducer which forms a polygonal multiple reflection surface on an ultrasonic solid delay medium and emits a longitudinal wave on a part of the reflection surface, and the longitudinal wave emits a longitudinal wave on another reflection surface. - an output transducer that receives longitudinal waves that have been subjected to transverse wave conversion and transverse wave-longitudinal wave conversion; An ultrasonic solid delay line characterized in that an ultrasonic diffused reflection area is provided at the main boundary surface to cause diffused reflection of ultrasonic waves. 2. The ultrasonic solid delay line according to claim 1, wherein the input transducer and the output transducer have the same width as the thickness of the ultrasonic solid delay medium and are orthogonal to the main boundary surface. 3. The surface roughness of the main boundary surface is λ of the wavelength λ of the propagating ultrasonic wave.
The ultrasonic solid state delay line according to claim 1, wherein the ultrasonic solid state delay line has a wavelength of λ/20 to λ/5.