JPS61139114A - Manufacture of ultrasonic delay line - Google Patents

Abstract

PURPOSE:To reduce an unnecessary reflected signal by using a printing screen, whose sectional shape of a printing hole part has minimum dimensions in the position slightly higher than the center in the thickness direction of this hole part and becomes larger in dimension as going from this position toward both ends in the thickness direction, when an unnecessary reflection absorbing material is printed on the side face of a glass delay medium. CONSTITUTION:When an unnecessary reflection absorbing material 9 which attenuates the unnecessary reflection is printed on the side face of a glass delay medium 8, a printing screen 10 is used whose sectional shape of a printing hole part 10a has minimum dimensions in the position slightly higher than the center in the thickness direction of this hole part and has larger dimensions according as going from this position toward both ends in the thickness direction. When this printing screen 10 is used to print the unnecessary reflection absorbing material 9, print finishing as shown in a figure C is attained. That is, the upper part as well as the lower part of the unnecessary reflection absorbing material 9 have less sagging because the printing hole part 10a of the printing screen 10 has the lower part slowly inclined and the upper part of the unnecessary reflection absorbing material 9 is squeezed up when the printing screen 10 is raised. Thus, the unnecessary reflection is reduced, and an ultrasonic delay line excellent in characteristic is obtained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method of manufacturing an ultrasonic delay line.

Conventional technology Ultrasonic delay lines are used for demodulating color signals in PAL television systems, improving image quality in NTSC television systems,
It is widely used to remove cross colors in video tape recorders and improve the S/N ratio.It is mainly used to improve the image quality of video equipment. Recently, with the rapid increase in sales of video tape recorders, the market size of ultrasonic delay lines has also increased significantly.

Such a conventional ultrasonic delay line will be explained using FIG. 3. In FIG. 3, 1 is a glass delay medium, 2 is an unnecessary reflection absorbing material, 3 is a piezoelectric element, 4 is an electrode, 5 is a lead wire, and 6 is an ultrasonic propagation path. Two piezoelectric elements 3 are attached to the glass delay medium 1, one for input and one for output, which is an electric/acoustic transducer that converts an electric signal into an acoustic signal and acts vice versa. The propagation path 6 of the ultrasonic wave, which is the acoustic signal at that time, is shown by a solid line. Furthermore, the piezoelectric element 3 for signal input/output is provided with an electrode 4, and a lead wire 5
is installed. Further, an unnecessary reflection absorbing material 2 for attenuating unnecessary reflections is attached to the side surface of the glass delay medium 1. Here, the unnecessary reflective absorbing material 2 is attached by a printing method. Figure 4 shows the procedure. A shows the state before printing, and the printing portion of the printing screen 7 has a uniform diameter. B shows the state at the time of printing, where a portion of the mark is filled with unnecessary reflective absorbing material 2. After marking C, when the printing screen 7 is raised, the unnecessary reflection absorbing material 2 is likely to dwindle and its diameter becomes larger than in the middle column.

Problems to be Solved by the Invention According to the above-mentioned conventional configuration, as the diameter of the unnecessary reflection absorbing material 2 increases as described above, the attenuation of the main signal is greater than that at the time of design, and as a result, other signals are relatively attenuated. Unnecessary reflected signals become large. The unnecessary reflection characteristics are shown in FIG.

An object of the present invention is to provide a method for manufacturing an ultrasonic delay line that solves the above problems.

Means for Solving the Problems In order to solve the above-mentioned problems, the Jil old-wave slow-wave delay line manufacturing method of the present invention provides a method for printing an unnecessary reflection absorbing material for attenuating unnecessary reflections on the side surface of a glass delay medium. A printing screen is used in which the cross-sectional shape of the hole has its minimum size at a position slightly above the center in the thickness direction, and gradually increases in size from that position toward both ends in the thickness direction.

Function: In the printing screen configured as described above, the lower part of the printing hole has a gentle slope, and when the printing screen is pulled up, the upper part of the unnecessary reflective absorbing material is squeezed up, so that the printed unnecessary reflective absorbing material is removed from both the upper and lower parts. It has a shape with less sag.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is an explanatory diagram of a method for manufacturing an ultrasonic delay line according to an embodiment of the present invention, in which 8 is a glass delay medium, 9 is an unnecessary reflection absorbing material, and 10 is a printing screen.

In the printing screen 10, the cross-sectional shape of the printing holes 10a has a minimum dimension at a position slightly above the center in the thickness direction, and gradually becomes larger from that position toward both ends in the thickness direction. Both ends in the thickness direction have equal dimensions.

When unnecessary reflective absorbing material 9 is printed as shown in 8 using the printing screen 10 shown in FIG. 1A, a printed finish as shown in C is obtained. That is, the printing holes 10a of the printing screen 10 have a gentle slope at the bottom, and when the printing screen 10 is raised, the top of the unnecessary reflective absorbing material 9 is squeezed up, so that the unnecessary reflective absorbing material 9 sags at both the top and bottom. It becomes a shape with less.

In this way, there is no printing sag and the shape of the unnecessary reflection absorbing material 9 can be obtained as set, so as shown in FIG. 2, the unnecessary reflection is reduced by about 8 dB compared to the conventional example.

Effects of the Invention As described above, according to the present invention, printing sag of unnecessary reflective material does not occur, and therefore an ultrasonic delay line with excellent characteristics can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a method for manufacturing an ultrasonic delay line in an embodiment of the present invention, Fig. 2 is an explanatory diagram of characteristics of an ultrasonic delay line obtained by the same manufacturing method, and Fig. 3 is an explanatory diagram of an ultrasonic delay line obtained by the same manufacturing method. 4 is an explanatory diagram of the conventional ultrasonic delay line manufacturing method,
FIG. 5 is a diagram illustrating the characteristics of an ultrasonic delay line obtained by the same manufacturing method. 8... Glass delay medium, 9... Unnecessary reflection absorbing material, 1
0...Printing screen, 10a...Printing hole 1st
Figure (A) (B-n (C) Figure 4 (C-n)

Claims (1)

[Claims] 1. When printing an unnecessary reflection absorbing material that attenuates unnecessary reflections on the side surface of the glass delay medium, the cross-sectional shape of the printing hole becomes the minimum dimension at a position slightly above the center in the thickness direction,
A method of manufacturing an ultrasonic delay line using a printing screen that gradually becomes larger from that position to both ends in the thickness direction.