JPS63172902A - Thickness measuring instrument for metallic foil - Google Patents

Abstract

PURPOSE:To accurately measure the thickness of metallic foil by arithmetic operation by bringing a couple of probe rods into contact with the metallic foil to be measured lengthwise and supplying a constant current, and measuring the potential difference generated between said two points with the constant current. CONSTITUTION:The metallic foil 1 to be measured is mounted and fixed on a supporting base 5 and the probe rods 7 and 8 brought into contact with two lengthwise points A and B on the metallic foil 1. Then a constant current source 6 is connected to the probe rods 7 and 8 to supply the constant current between the two points A and B said metallic foil 1. The the potential difference generated between said two points A and B with the constant current is measured by a potentiometer 9, whose measured value is inputted to an arithmetic means 10. A thickness arithmetic means 10 calculates the thickness of the object metallic film 1 according to the input potential difference.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an improved means for measuring the thickness of gold Iil foil.

<Prior Art> An example of the prior art will be explained based on FIGS. 3 and 4. FIG. 3 is a conceptual diagram of contact-type thickness measurement, in which the metal foil 1 to be measured having a thickness d is measured by the contactor 201 of the measuring device 1F2.
202, and the moving distance of the other contact with one position as a reference is read using a precise scale function.

The example in FIG. 4 shows optical distance measuring devices 3 arranged oppositely.
．． The metal foil 1 to be measured is placed between the metal foils 1 and 4, and the thickness d is calculated from the measured values of the distance It from each measuring device to the surface of the gold scrap foil, and 12.

-<Problems to be Solved by the Invention> However, in the case of a contact type, there is a drawback that the overload of the contact may damage the metal foil or the contact portion may be bent.

Furthermore, in the case of the optical method, there is a drawback that measurement errors occur if the spot on which the light hits is not a flat surface because the metal foil is bent or distorted.

An object of the present invention is to provide a metal foil thickness measuring device that can solve these problems of the prior art.

Means for Solving the Problems> The structural feature of the present invention is that two points are separated by a certain distance in the longitudinal direction of a rectangular metal foil with uniform thickness and resistivity and a known distance in the width direction. a constant current means for flowing a constant current between the two points; a potentiometer means for measuring the potential difference between the two points; and a calculation means for determining the thickness of the gold a foil based on the constant current and the measured potential difference. The point is that it is equipped with the following.

According to the present invention, a potential difference due to a constant current supplied at a constant distance in the longitudinal direction of a rectangular gold foil with a uniform thickness and a known width is measured, and this measured value and a known width are measured. Thickness is calculated from the data.

Embodiments> The present invention will be described in detail based on FIG. In addition to having a covering, the distance W in the width direction and the resistivity have known values.

Reference numeral 5 designates an insulating material support stand on which the metal foil 1 to be measured is horizontally placed and supported, and hooks 501 and 502 at both ends clamp and fix the metal foil at both ends, and also hold the metal foil along its length. It is pulled with a weak force in the direction to prevent it from bending.

6 is a constant current source that emits a constant current ■, 7 and 8 are probe rods, and the distance is a constant distance in the longitudinal direction of the metal foil surface! Contact two points △ and B that are separated by , and supply a constant current ■ between A and 8.

Reference numeral 9 denotes a potentiometer, into which the potential between points located outside points A and B in the longitudinal direction is input in order to measure the potential difference VAB generated between points A and 8 by the current I.

Next, the present invention will be explained in detail with reference to FIG.

Generally, electrical resistance and resistivity are proportional, and the resistance of a conductor is proportional to its length and inversely proportional to its cross-sectional area. Hence the length!
, cross-sectional area S, and resistivity ρ, the resistance R of a conductor is expressed by the following equation.

R-ρ・l/S (1) On the other hand, in the metal foil 1 shown in FIG. 2, if the potential difference between A and 8 is VABs and the current is ■, then the resistance RAB between A and 8 is RAa=Vaa/I ( 2). Also, if we consider a thin metal foil to be a cube, its cross-sectional area S
is S-d-w (3) where the thickness of the metal foil is 61 and the width is W. Therefore, by substituting equations (2) and (3) into equation (1), d, = ρ・!・■／■AB-W (4) is obtained. In equation (4), ρ, i', I, and W are all known values as described above, so if the calculation of equation (4) is performed by measuring the potential difference VAB, the thickness d can be calculated. Is possible.

For example, if the metal foil is aluminum, the resistivity is ρ-2
, 75×10' Ω1). Here, the constant current is l
=2.00μ, distance between A and 8 is 1' = 7-5 c
m 1 width is w-7,5 (potential difference in case of 111 is i, o
The thickness d when ox io°3 (■) is
d-5,5x10"S(m)-55,0 (μm).

In addition to determining the thickness, the present invention can also be used to measure resistivity when the thickness is known but the resistivity is unknown. That is, based on equations (1) and (4), the resistivity ρ is ρ-d-W-vAB/l·■ (5) Therefore, the resistivity can also be measured.

Note that the probe rods 7 and 8 can be placed completely apart from both ends of the metal foil. If you understand it accurately, you can achieve your goal.

<Effects of the Invention> As explained above, according to the present invention, it is possible to accurately calculate and measure the thickness of metal foil using a constant current source and a potentiometer, and the problems of the prior art can be solved. can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram explaining its operation, and FIGS. 3 and 4 are block diagrams showing an example of the prior art. 1...Metal foil to be measured 5...Support stand 6...
Constant current source 7.8... Probe rod 9... Potentiometer 10... Thickness calculation means 11112, -

Claims (1)

[Claims] A constant current means that flows a constant current between two points separated by a certain distance in the longitudinal direction of a rectangular metal foil with uniform thickness and resistivity and a known distance in the width direction, and measures the potential difference between the two points. A metal foil thickness measuring device comprising a potentiometer means for measuring the constant current and a calculating means for calculating the thickness of the metal foil based on the constant current and the measured potential difference.