JPS62185151A - Foreign matter detection in dielectric body by microwave - Google Patents

Abstract

PURPOSE:To achieve a smaller size and higher operability of the equipment, by making a sample approach and move to simple transmission line produced simply by having a dielectric plate equipped with a metal strip. CONSTITUTION:Metal plates 21 and 22 are arranged on a dielectric plate 1 at an appropriate interval and a slot line 3 is formed with a clearance obtained. A high frequency power is supplied from a power source G at one end of a transmission line while non-reflection final end is connected to the other end of the line to detect a reflected wave. Or a power detector is placed to detect changes in a passing power and a detection signal is computer processed. Here, for example, a sample T1 of a flat plate is moved along the surface of a metal plate crossing the line 3. As the length and size of a foreign matter (f) contained in the dielectric body T, the aspect thereof to the feeding direction and the like are at random factors, the detection can be done easily by changing the angle between the clearance and direction of feeding a sample.

Description

[Detailed Description of the Invention] A1. Purpose of the Invention [Field of Industrial Application] In recent years, with the development of computers, electrical components (LSI-ultra LSI, etc.) have become smaller. There have been cases where fine metal pieces are the cause of yσ entanglement failures.On the other hand, in the case of Zetsushichifu used in crystal power, fine or foreign matter of the same value of metal inside the crystals has become the cause of failures. There is.

The present invention provides dielectric fibers or ? A: The purpose is to detect foreign substances contained in electric cloth or dielectric plates.

[Conventional technology]

For similar purposes, published patent publication No. 59-214748 “
“Method for detecting conductive substances in fibrous glass” and opening/closing 13
No. 0-87844, ``Method and device for detecting conductive substances in glass fibers or glass fiber-loaded products,'' has been disclosed. This is a method of detecting discharge phenomena that occur at certain locations. On the other hand, there is a known method using microwaves, ``Method for detecting defects in glass fibers'' published in Japanese Patent Publication No. 80-20138, which uses a waveguide in the transmission line and inserts the sample to be tested into it. It is something.

[Problem that the invention seeks to solve]

Therefore, the former conventional method uses a high voltage and a large amount of power, which poses a safety problem, and the device becomes large. Furthermore, in the latter method, the sample is inserted into a waveguide, making it inconvenient to handle large samples.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting foreign matter in a dielectric body that solves the above-mentioned problems.

Summary: Structure of the Invention [Means for Solving the Problems] The present invention propagates a continuous wave or frequency swept microwave signal through a slot line or an equivalent transmission line, and transmits a dielectric material to be measured. , electromagnetically coupled with this, and moving the dielectric in a direction crossing the transmission line L,
IE is a method for detecting foreign matter in a dielectric material using microwaves, which is characterized by detecting the presence of foreign matter by reading relative electromagnetic changes between a normal dielectric material and a dielectric material of the same type containing foreign matter.

Note that the above-mentioned relative electromagnetic change is a relative change in impedance or insertion loss, detection of reflected waves, change in passing power, or the like.

[For production]

By propagating a microwave signal through a slot line or equivalent transmission line, and moving the sample across the transmission line and electromagnetically coupling it, the condition of a normal sample and that of a foreign object can be determined. Since an electromagnetic change occurs from the current state, the presence of a foreign object can be easily detected by detecting the difference as a reflected wave, insertion loss, or change in impedance, and processing the signal output with a computer.

Since a slot line or an equivalent transmission line is used as the microwave transmission line, minute impedance changes at the coupling portion with the microwave can be detected and high resolution portions can be detected.

Although microwave oscillation signal sources can be of a single frequency,
By using the sweep frequency, it is possible to obtain signals corresponding to each frequency from one foreign object. This has the effect of increasing the resolution for detection.

〔Example〕

Figures 1 to 3 show a dielectric substrate l with a metal plate (or metal foil strip) 2. and 22 are arranged at appropriate intervals and a slot line is formed in the gap 3. High frequency power is supplied from the power supply G from one end of the transmission line, and a non-reflection termination is connected to the other end of the line. Then, the reflected wave is detected, or a power detector is installed to detect a change in the passing power, and the detected signal is processed by a computer.

Figure 2 shows a flat (cloth-like) sample T that intersects line 3.
1 is moved along the metal plate surface, and FIG. 3 shows a fibrous sample T2. The foreign matter f contained in the dielectric T is
Since the size, direction with respect to the feeding direction, etc. are at random, detection is facilitated by changing the angle 0 between the slot 3 and the sample feeding direction. The feeding mechanism can be either a badge type or a belt conveyor type.

According to an experiment, using microwaves with a frequency of 10 GHz, a material with a diameter of 10 g and a length of 5
It was possible to detect approximately 1 fibrous metal piece f.

It was also possible to detect a foreign object f with a diameter of about 10 l and a length of about 2ffiII+.

FIG. 4 shows several examples of transmission lines such as slot lines and transmission lines. The ground plate 4 shown in FIG. In the same figure, (B) is a coplanar waveguide, and (C) is an H guide.

C. Effects of the Invention As mentioned in -F, the present invention moves a sample close to a simple transmission line consisting of a metal strip attached to a dielectric plate, so the device is small and easy to carry. It is easy to exchange samples and has excellent operability. Furthermore, since high voltage and large power are not used, it is safe and the device can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view illustrating a thrower I line as a transmission line of the present invention, FIG. 2 is a flat test tube, and FIG.
The figure is an explanatory diagram of the procedure for detecting foreign matter in a ta fibrous sample, and Figure 4 (
A) (B) (C) are cross-sectional views of other transmission lines. G...Microwave signal power supply, l...Dielectric material, 2,...
22...Metal plate, 3...Slot line, 4...
Ground plate, TI... plate-like sample, T2... fibrous sample.

Claims (1)

[Claims] (1) Propagate a continuous wave or frequency swept microwave signal to a slot line or equivalent transmission line, electromagnetically couple the dielectric to be measured, and connect the dielectric to the transmission line. A method for detecting foreign matter in a dielectric using microwaves, which is characterized in that the presence of a foreign matter is detected by reading the relative electromagnetic change between a normal dielectric and a dielectric of the same type containing a foreign matter by moving the dielectric in a direction crossing the dielectric. .