JPS60216621A - Ultrasonic wave delay line - Google Patents

Abstract

PURPOSE:To reduce noise of an ultrasonic wave delay line by providing a piezoelectric element for absorbing spurious reflection between whose electrodes are connected electrically to a path other than a normal ultrasonic wave propagating path of an ultrasonic wave delay medium so as to reduce the spurious reflection. CONSTITUTION:An output piezoelectric element 2 and an input piezoelectric element 3 are fitted to one plane of polygon and one side of an ultrasonic wave delay medium 8 connected with a lead wire 1 is provided with a lower face electrode 7 so as not to be connected to the electrodes of the input piezoelectric element 3 and the output piezoelectric element 2. Then a piezoelectric element 9 for absorbing spurious reflection having an upper face electrode 6 is adhered to a part other than the normal ultrasonic wave propagating path and a lead wire 5 having a resistance is connected to the upper face electrode 6 with solder 4 and the tip of the lead wire 5 is connected to the lower face electrode 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ultrasonic delay line that delays an electrical signal for a certain period of time.

Conventional Structures and Problems Generally, in an ultrasonic delay line, an ultrasonic wave propagates along a predetermined path in a fixed period of time, but some ultrasonic waves propagate through paths other than this path. These ultrasonic waves have a delay time different from a predetermined delay time, and are called unnecessary reflections to distinguish them from the original ultrasonic waves. Unnecessary reflections become noise to the original ultrasonic waves, so they need to be attenuated as much as possible.

Unwanted reflections include those that travel back and forth along the regular propagation path several times, those that propagate along paths other than the regular propagation route, and those that are caused by leakage signals on lead wires and printed circuit boards. Reflections that propagate along paths other than the normal propagation path are called other unnecessary reflections. In order to reduce other unnecessary reflections, it is effective to attach an unnecessary reflection absorbing material to a path other than the normal propagation path, or to provide a means for preventing scattering on the reflecting surface.

Conventionally, unnecessary reflection-absorbing materials have been made of epoxy resin mixed with metal powder. This unnecessary reflection-absorbing material partially increases the mass of the delay medium and attenuates the ultrasonic waves propagating through the unnecessary reflection-absorbing material, and the amount of attenuation is not sufficient.

OBJECTS OF THE INVENTION The present invention provides an ultrasonic delay line with smaller cine reflections and less noise than conventional unnecessary reflection absorbers by obtaining an unnecessary reflection absorption effect superior to that of conventional unnecessary reflection absorbing materials.

Structure of the Invention The present invention has the effect of increasing the mass by attaching a piezoelectric element with electrically coupled electrodes in place of the conventional unnecessary reflection absorbing material. It converts the vibrational energy of the ultrasonic waves passing through the section into electrical energy and releases it, increasing the effect of unnecessary reflection and absorption.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 of the drawings. As shown in the drawing, an output piezoelectric element 2 and an input piezoelectric element 3 are attached to one plane of a polygon, and an input piezoelectric element 3 and an output piezoelectric element are attached to one side of an ultrasonic delay medium 8 to which a lead wire 1 is connected. A lower surface electrode 7 is provided by vacuum evaporation so as not to contact the electrodes of the piezoelectric element 2, and a piezoelectric element 9 for unnecessary reflection and absorption having an upper surface electrode 6 is attached to a portion other than the normal ultrasonic propagation path, and these upper surface electrodes 6 are attached. Next, a lead wire 6 having a resistance is connected to the solder 4, and the tip of this lead wire 6 is connected to the lower surface electrode 7.

In this way, the ultrasonic waves propagating through the part to which the piezoelectric element 9 is attached will be attenuated by the mass of the piezoelectric element 9 for unnecessary reflection and absorption, and the vibration energy of the ultrasonic wave will be converted into electric energy by the piezoelectric element 9 for unnecessary reflection and absorption. , and the lower electrode 7
A current flows through the lead wire 5 that connects the top electrode 6 to the lead wire 6, and as a result, the lead wire 6 emits Joule heat, which can further absorb and attenuate ultrasonic waves, reducing unnecessary reflections compared to conventional methods. A small ultrasonic delay line can be obtained.

Effects of the Invention As described above, the present invention increases the effect of absorbing unnecessary reflections by pasting a pressure bonding element in place of the conventional unnecessary reflection absorbing material made of epoxy resin mixed with metal powder. It is possible to obtain an ultrasonic delay line with less noise, which is greatly useful for improving the image quality of televisions and VTRs.

[Brief explanation of the drawing]

FIG. 1 is a top view of an ultrasonic delay line according to an embodiment of the present invention, and FIG. 2 is a side view of the same. 1... Lead wire, 2... Piezoelectric element for output, 3... Piezoelectric element for input, 4... Solder, 5... Lead wire with resistance, 6...
・Top electrode, 7...Bottom electrode, 8...
Ultrasonic delay medium, 9...Piezoelectric element for unnecessary reflection absorption. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] In a path other than the normal ultrasonic propagation path of the ultrasonic delay medium,
An ultrasonic delay line equipped with a piezoelectric element that electrically connects electrodes to absorb unwanted reflections.