JPS61288511A - Ultrasonic wave solid-state delay line - Google Patents

Abstract

PURPOSE:To obtain a non-dispersive delay line having a high frequency whose center frequency is nearly 100MHz with good characteristic and ease of manufacture by forming a polygonal multiplex reflecting face to an ultrasonic wave solid-state delay medium, arranging transducers and providing an ultrasonic wave absorbing member. CONSTITUTION:For example, pentagonal multiple reflection faces 2-7 are formed to an ultrasonic wave solid-state delay medium 1, an input transducer 10 irradiating a longitudinal wave 8 and an output transducer 11 receiving longitudinal waves subjected to longitudinal/lateral wave conversion 9 coming from reflected faces, 5, 7 and subjected to lateral/longitudinal wave conversion are arranged to reflection faces 5, 7. A longitudinal spurious wave irradiated from the transducer 10 is subjected to longitudinal/lateral wave conversion at major boundary faces 12, 13 and the converted lateral wave is made incident on ultrasonic wave absorbing member 14, 15, which are provided at least at a part of the main boundary faces 12, 13 in parallel with and orthogonal to the faces 2-7, the thickness of the input transducer 10 and the output transducer 11 is the same as that of the ultrasonic wave solid-state delay medium and they are orthogonal to the major boundary faces 12, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic solid-state delay line, and in particular to an ultrasonic solid-state delay line that has good characteristics, is easy to manufacture, has a low cost, and has an extremely high center frequency, for example! It is related to a high frequency ultrasonic solid state delay line of about 00 MHz.

[Technical Background of the Invention] Low-frequency ultrasonic solid-state delay lines have been known since 1997 (Japanese Patent Publication No. 47-27574, Japanese Patent Publication No. 46-22818).
No. 3,581,247). These low-frequency ultrasonic solid-state delay lines form polygonal multiple reflection surfaces, and as shown in FIG. Using a bulk wave, the spurious waves are absorbed or diffusely reflected by an absorbing material or a diffused reflection surface 36.37 provided on a 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, 100 MHz.

For this reason, similarly using a transverse bulk wave, the thickness t of the delay medium M is adjusted to the extent that the sidelobes and other expanded waves 38 are not reflected and become spurious as shown in FIG. 8, and the output transducer 32. It was thicker than that.

[Problems in the Background Art] As shown in FIGS. 7 and 8, such an ultrasonic solid state delay line is prone to spurious noise due to the portion 39 of the delay medium M, which is thicker than the output transducer 32 and 33, resulting in a delay. The waves incident on the main boundary surface of the medium have 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, and the retardation medium becomes thick and has to be manufactured one by one. This has the disadvantage of increasing costs.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional difficulties, and provides a high-frequency non-dispersive ultrasonic solid with an extremely high center frequency of about 100 MHz, which has good characteristics, is easy to manufacture, and has a low cost. It is intended to provide a delay line.

[Summary of the Invention] In order to achieve the above object, the ultrasonic solid delay line of the present invention is provided by forming a polygonal multiple reflection surface on the ultrasonic solid delay medium, and forming a vertical reflection surface on a part of the reflection surface. An incoming quadratic transducer that emits waves and the longitudinal waves emit longitudinal waves at another reflecting surface.
an output transducer that receives longitudinal waves that have been subjected to transverse wave conversion and transverse wave-longitudinal wave conversion; The ultrasonic wave absorbing material is provided with an ultrasonic absorbing material on which a transverse wave, which has been converted into a longitudinal wave and a transverse wave, is incident on the main boundary surface.

[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, in the ultrasonic solid state delay line of the present invention, pentagonal multiple reflection surfaces 2 to 7 are formed in an ultrasonic solid state delay medium 1 such as glass, and each of the reflection surfaces Part 2.4
, an input transducer 10 emits a longitudinal wave 8 (indicated by a dotted line), and the 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
3, in the illustrated example almost the entire surface, the longitudinal wave spurious emitted from the input transducer 10 undergoes longitudinal-transverse wave conversion at the main interface 12.13;
Ultrasonic absorbing material 14 such as epoxy resin on which transverse waves are incident
．． 15 are provided.

The input transducer 10 and the output transducer 11 have the same ff(t) as an ultrasonic solid state delay medium.

), and perpendicular to the main boundary surface 12.13 (shown by
(indicated by zR).

Further, the main boundary surfaces 12, 13 are smoothed to a degree of smoothness obtained by cutting with a slicing machine such as a wafer sawing machine.

According to the ultrasonic solid-state delay line configured in this way, the longitudinal wave 8 radiated at 90° from the input transducer 10 placed on the reflecting surface 2 of the ultrasonic solid-state delay medium 1 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 another reflecting surface 5, 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 appears in addition to the longitudinal wave 8a as reflected waves. 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. In addition, C10 is the propagation speed of longitudinal waves in the medium 2, 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 (1) 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 O, 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 0314 and the fluid medium (2) is air, the incident angle α is approximately 456, the amplitude of the reflected longitudinal wave 8a is O, and the incident longitudinal wave 8 is completely converted into a transverse wave 9. A transformation 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. 5.

This transverse wave undergoes total reflection of a multi-transverse wave at the reflecting surface 6, and furthermore, 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 transferred to the reflecting surface of the ultrasonic solid delay medium l. Output transducer 11 located at 4 and 9 on its side
Incident at 0°.

As mentioned above, the ultrasonic solid-state delay line according to the present invention has the input transducer 10 and the output transducer 11 having the same thickness (t, ) as the ultrasonic solid-state delay medium, so that the output transducer 10 and 11 can operate in modes other than 0 mode. Since it essentially has the function of not transmitting or receiving waves, it is easy to configure a delay line (non-dispersive mode).

However, as shown in FIG. 3, waves almost parallel to the main boundary surfaces 12 and 13 are generated, resulting in spurious waves 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 boundary surface 12
．． Since the ultrasonic absorber 14.15 is provided on at least a part of 13, almost the entire surface in the illustrated example, the vertical wave emitted from the input transducer 10 and incident at an angle close to parallel to the main boundary surface 12.13 As explained in Fig. 5, at least a part of the spurious wave 8 is converted into a longitudinal wave-transverse wave mode and becomes a transverse wave 9 with a large angle change (Fig. 4), and the spurious wave 8 becomes a transverse wave 9 with a large angle change (Fig. 4), and the main boundary surface 12. Since the spurious wave is incident on the absorber 14.15 at a small angle β, the spurious wave is absorbed by the ultrasonic absorber 14.15 with a large absorption effect and removed. Note that even if this spurious wave is not removed by one reflection at the main boundary surface 12.13, it is removed by repeating several reflections at the main boundary surface 12.13.

Moreover, since the main boundary surfaces 12 and 13 are smoothed, this longitudinal wave-transverse wave conversion is performed smoothly.

Note that since the input transducer 10 and the output transducer 11 are perpendicular to the two parallel main boundary surfaces 12.13, the rectilinear wave radiated from the input transducer 10 travels straight between the main 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 polygonal multiple reflection surface 2 to 7 (FIG. 1) 1i of a previously designed shape and size: a block 4o of the formed ultrasonic solid retardation medium 1 is prepared. Tin electrodes 41 and 42 are attached to a portion 2.4 of the reflective surface by vapor deposition. in addition,
An input transducer strip 43 and an output transducer strip 44 are arranged. In this state, the delay time is measured, and the reflective surface 6 is polished by the required amount (main key!).

This is cut by a slicing machine to obtain each unit 45 including an input transducer 10 and an output transducer 11. At this time, the delay time is measured, and if necessary, the reflective surface 6 is refined (fine adjustment). Epoxy P4 resin is adhered to the main boundary surface of each unit 15 as an ultrasonic absorbing material 36, 37 (Fig. 1↓).

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 ultrasonic solid-state delay line can be obtained. Additionally, the input and output transducers are cut to the same thickness as the ultrasonic solid state delay medium, facilitating the construction of non-dispersive mode delay lines.

Furthermore, if this block is cut with a slicing machine such as a wafer sawing machine, the main interface 12.1
3 will be smoothed.

[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 emitted from the input quadrature transducer become longitudinal waves. - transverse wave conversion and transverse wave-longitudinal wave conversion to be incident on the output transducer, and the spurious of the longitudinal wave radiated from the input transducer is transmitted to at least a part of the main boundary surface perpendicular to the reflecting surface at the main boundary. Longitudinal wave in the plane -
Since it is equipped with an ultrasonic absorber that receives transverse waves that have been converted into transverse waves, it can completely absorb spread waves such as site lobes, allowing only straight waves to be used, and has good characteristics. A non-dispersive ultrasonic solid state delay line is obtained.

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 the drawing]

Figure 1 is a plan view of the Mi sonic solid-state delay line according to the present invention, Figure 2 is a side view of the delay line, Figure 3 is a side view of the delay line before completion, and Figure 4 is the completed delay line. The later side view, FIG. 5 is an explanatory diagram of the operation of the same delay line, the sixth side view, FIG. 5 is an explanatory diagram of the operation of the same delay line, and FIG. 6 is an explanatory diagram when manufacturing the delay line, 7-8 are side views of conventional delay lines. 1... Ultrasonic solid delay medium 2 to 7... Multiple reflection surface 8... Longitudinal wave 9... Transverse wave 10... Input transducer 11... Output transducer 12.13... Main boundary surface 14.15...Ultrasonic absorbing material

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 absorbing material is provided on the main boundary surface into which a longitudinal wave-transverse wave converted transverse wave is incident. 2. The ultrasonic solid delay line according to claim 1, wherein the input transducer and the output transducer have the same thickness as the ultrasonic solid delay medium and are orthogonal to the main boundary surface. 3. The ultrasonic solid delay line according to claim 1, wherein the main boundary surface is smoothed.