JPH04207625A - Ultrasonic wave delay line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention increases the number of processing circuits for Y/C separation circuits (Y signal: luminance signal, C signal dichroic signal) of video equipment such as high-definition video tape recorders. Due to the increased complexity, a difference occurs in the time delay between the Y signal and the C signal, and this relates to an ultrasonic delay line with a delay time of several μS to correct this time difference.

BACKGROUND OF THE INVENTION FIG. 3 shows an example of the structure of an ultrasonic delay line with a typical delay time of several tens of microseconds. In Fig. 3, 1 is an ultrasonic delay medium such as glass, 2 is an electrode, 3 is solder or adhesive, 4 is an input transducer, 5 is an output transducer, 6
is a lead wire for applying a signal voltage, 7 is a lead wire for extracting a delayed signal, 8 is a lead wire for grounding, and 9 is an unnecessary lead wire made of epoxy resin containing metal powder such as tungsten to absorb unnecessary vibrations of ultrasonic waves. A reflection absorbing material 10 is a propagation path for a regular delay signal.

The principle of operation of this ultrasonic delay line is that by applying a signal voltage to the input signal voltage application lead wire 6, the input transducer 4 is excited and emits ultrasonic waves to the ultrasonic delay medium 1. This ultrasonic wave propagates as a transverse wave inside and on the surface of the ultrasonic delay medium 1 while repeating reflections along the normal delay signal propagation path 10, and reaches the output transducer 5 with a delay time of several tens of microseconds. 5 vibrates. This vibration is converted into an electric signal and taken out from the lead wire 7 for taking out the delayed signal. However,
Since ultrasonic waves propagate with a certain directivity angle, there are signals with a delay time different from the normal delay time. In order to attenuate this signal, as is well known, an unnecessary reflection absorbing material 9 is applied to the surface of the ultrasonic delay medium 1 other than the normal propagation path.

Problems to be Solved by the Invention In a conventional configuration in which ultrasonic waves are reflected several times or more at the end face of an ultrasonic delay medium, the normal delay time becomes longer than several tens of microseconds, and the normal delay time, which is as short as several microseconds, becomes long. When an ultrasonic delay line having a delay time is realized on a delay line having a conventional configuration, a simple ultrasonic delay medium configuration in which the ultrasonic wave is reflected one time or less is obtained. However, in the conventional configuration, the propagation path length of the regular ultrasonic wave is short, so the ultrasonic wave travels almost straight, and even if unnecessary reflection absorbing material is applied to the surface of the ultrasonic delay medium other than the propagation path of the regular delayed signal, , it is not possible to sufficiently suppress unnecessary signals. In particular, (2n+1) times the normal delay time (n=
1.2.3. It becomes difficult to suppress unnecessary signals having a delay time of .

As described above, in the conventional configuration, when the normal delay time is as short as several microseconds, it is difficult to suppress unnecessary signals, which disturbs the waveform.

The present invention solves these problems and provides an unnecessary reflection absorbing material and a coating position for effectively suppressing unnecessary signals.

Means for Solving the Problems In order to solve the above problems, the present invention provides a system in which the reflection of ultrasonic waves is 0.
An unnecessary reflection absorbing material made of flexible resin is applied on at least one plane in the thickness direction of an ultrasonic delay medium such as glass or the like, and on the regular ultrasonic propagation path. It is.

According to the present invention, unnecessary signals are suppressed and a waveform with extremely small irregularities can be obtained.

Embodiment FIG. 1 shows an ultrasonic delay line according to an embodiment of the present invention having a delay time of several μs, but the number of reflections of the ultrasonic wave is 0.

In FIG. 1, 11 is a rectangular ultrasonic delay medium such as glass, 12 is an electrode, 13 is solder or adhesive, 1
An input transducer 4 is attached to one end surface of the delay medium 11, and an output transducer 15 is attached to the other end surface of the slow medium 11, facing the input transducer 14. 16 is a lead wire for applying a signal voltage, 17 is a lead wire for extracting a delayed signal, 18 is a lead wire for grounding, 19 is an unnecessary reflection absorbing material made of flexible epoxy resin, etc., and the thickness of the delay medium 11 is It is applied on the plane of the direction.

20 is a propagation path of the normal delay signal. Here, since the basic operation is the same as the conventional example, the description thereof will be omitted.

This embodiment employs a configuration in which an unnecessary reflection absorbing material 19 made of flexible resin is applied to the entire surface of the regular ultrasonic propagation path 20 of the ultrasonic delay medium 11. This is because the normal ultrasonic propagation path length is short, so the ultrasonic waves emitted from the input transducer 14 travel almost straight and reach the output transducer 15. Even if the unnecessary reflection absorbing material 19 is applied to the surface of the ultrasonic delay medium 11 other than the propagation path 20 of the normal delay signal as in the past, the normal delay time is (2n+1) times (n=1.2, 3. This is because an unnecessary signal having a delay time of . As in this embodiment, unnecessary reflective absorbing material 19 is provided on the entire surface of the regular ultrasonic propagation path 20 of the ultrasonic delay medium 11.
By adopting a configuration that applies
The amount of attenuation of an unnecessary signal with a delay time of 2n+1) times (n=1.2, 3...) is (2n+1)A times (n=
1.2,3. ), it is possible to obtain a large suppressing effect. Furthermore, the unnecessary reflection absorbing material 19 is limited to a flexible resin. The reason is,
Even if ultrasonic waves are incident inside a non-flexible resin, they will not be attenuated (scattered, causing waveform disturbances.On the other hand, flexible resins are made of an elastic material such as rubber). Due to its properties, it has a strong effect of absorbing ultrasonic waves inside the resin (because there is less scattering).As a result, the waveform is less disturbed (the original purpose is to suppress unnecessary signals). .

FIG. 2 shows the waveform characteristics of the ultrasonic delay line according to this embodiment, and it can be seen that the waveform characteristics are greatly improved when compared with the waveform characteristics according to the conventional configuration shown in FIG.

Note that the unnecessary reflection absorbing material 19 may be applied to both sides of the ultrasonic delay medium 11 in the thickness direction, or may be applied only to one side.

In addition, not only on the regular propagation path, but also on the ultrasonic delay medium 1
It may be applied to the entire surface of 1.

The present invention also provides a human, output transducer 14.15.
The present invention can also be applied to a configuration in which the ultrasonic wave is reflected once by attaching the ultrasonic waves to the same end face.

Furthermore, this embodiment has input/output and grounding lead wires 16.1.
7.18 is attached, but these may be removed and a contact structure using a metal leaf spring or a connector in which a conductor is embedded in an insulator may be used.

Effects of the Invention According to the present invention, (2n-1> times (n=1
．． It is possible to sufficiently suppress unnecessary signals (2.3...) and obtain an ultrasonic delay line with excellent waveform characteristics and a short delay time of several μS.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the structure of an ultrasonic delay line according to an embodiment of the present invention, FIG. 2 is a diagram showing waveform characteristics of an ultrasonic delay line according to an embodiment of the present invention, and FIG. 3 is a general diagram. FIG. 4 is a plan view showing the structure of a conventional ultrasonic delay line, and FIG. 4 is a diagram showing waveform characteristics of an ultrasonic delay line having a delay time of several μS using the conventional structure. 11... Ultrasonic delay medium, 12... Electrode, 13... Solder or adhesive, 14...
... Input transducer, 15 ... Output transducer, 16 ... Lead wire for signal voltage application, 17 ... Lead wire for taking out delayed signal, 18 ... ...Leath wire for ground, 19...
・Propagation path of unnecessary reflection absorbing material, 20...regularly delayed signal. Name of the agent: Patent attorney Haruaki Ogata Two people: Figure 1, No. 7, Ultra sound, Weekly, y body / 2 --- Den Saihei, Yunko East road, Figure 2, R, Fukin, 42 Sue → Figure 3 Scraps 1 Seat 2 Gakudo □

Claims (1)

[Claims] An unnecessary reflection-absorbing material made of flexible resin is placed on at least one plane in the thickness direction of an ultrasonic delay medium such as glass, where ultrasonic waves are reflected 0 or 1 time, and on the normal ultrasonic propagation path. Ultrasonic delay line made by coating.