JPS60249067A - Characteristic measuring device of conductive film - Google Patents

Abstract

PURPOSE:To measure characteristics of a conductive film by non-contact, at a low cost and with high accuracy by positioning a conductive film between a pair of eddy current detectors, and measuring an eddy current of the conductive film. CONSTITUTION:An eddy current of a conductive film 2 moved at a prescribed speed through a transfer roll 3 is detected by eddy current detectors 1a, 1b which are opposed by placing the film 2 inbetween. Its detecting signal is brought to operation processing by an average arithmetic unit 5 through an amplifier 4, and an obtained electric resistance value is indicated on an indicator 6. In this way, characteristics of the conductive film 2 are measured by non-contact, at a low cost and with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a characteristic measuring device for measuring specific values such as conductivity and conductive thin film thickness of a conductive film.

[Prior art] For conductive films, conductive thin films of, for example, gold, silver, copper, aluminum, nickel, chromium, and various metals containing these as main components are directly coated on a non-conductive base material 1 such as a plastic film. Alternatively, there is a selective light transmitting sheet formed in combination with a high refractive index dielectric layer, or a selective light transmitting sheet formed of indium oxide and/or tin oxide as a conductive thin film with a thickness of 2,000 to 5,000 people. These films are transparent in the visible light range and selectively reflect the infrared wavelength range (generally exhibiting an area electrical resistance of 0.5 to 20 Ω/hole), and are used to save energy in buildings, residences, etc.

It is effective in terms of solar energy utilization, etc.

In addition, a thickness of 50 mm made of the above-mentioned indium oxide and/or tin oxide, palladium, gold, etc. on plastic etc.
A so-called IF film in which a conductive thin film of up to 1,000 people is formed is known. This film is widely used for electrophotographic recording, displays such as EL lamps, light curtains, transparent switches, electrostatic shielding, photoelectric conversion elements such as solar cells, and surface heating elements (usually 50Ω/low , 10 does not show the area electrical resistance of Ω/[].

In measuring the properties of these conductive films, when used as a selectively transparent sheet, the film thickness is an important characteristic, and the transmittance and/or infrared reflectance detector or X-ray thickness The film thickness was measured by calculation. When using the latter as a conductive film, its electrical resistance is an important property, and the area electrical resistance between electrodes that are in direct contact with the film surface is measured to determine the properties of the conductive film.

[Problems and Objects of the Invention] Conventionally implemented transmittance and/or reflectance methods not only require high cost detection equipment but also lack sufficient detection accuracy. Furthermore, although the X-ray method has high detection accuracy, the cost of the equipment is very high, so there are almost no examples of its use. On the other hand, the method of measuring electrical resistance by directly contacting the surface of a conductive film not only causes scratches and scratches on the surface of the film, reducing the product value, but also may not be usable at all depending on the application, making it difficult to use industrially. There has been a desire for a method to quickly and accurately measure characteristics at low cost.

The present invention is an IC device developed in view of such flatness, and aims to provide an apparatus that can measure the thickness or electrical resistance of a conductive film at low cost and with high accuracy without contacting the film surface. .

[Structure and operation of the invention 1 The above objects are achieved by the invention as follows.

However, the present invention is characterized in that when measuring the characteristics of a conductive film, the 6ffi film is positioned between a pair of eddy current detectors arranged oppositely at a predetermined interval. This is a device for measuring the characteristics of conductive films.

The present invention described above has the discovery that when an eddy current detector measures an eddy current in a conductive film, the output is proportional to the electrical resistance of the conductive film, and the present invention also provides a metal layer with a constant electrical resistance. Then, it was discovered that the electrical resistance of the film is proportional to the film thickness.

Therefore, the characteristics of the conductive film specifically refer to its electrical resistance or film thickness.

The details of the present invention will be explained below based on examples and drawings.

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of its measuring circuit. FIG. 1 shows an example in which the present invention is applied to an inspection apparatus for quality control of conductive films. In the figure, 2 is a conductive film supported by a transport roll 3, which is transported at a predetermined speed. Eddy current detectors 1a and 1b are mounted facing each other with a conductive film in between.

As is well known, an eddy current detector is a sensor that generates alternating magnetic lines of force when a high-frequency current is passed through a ferromagnetic probe wrapped in a coil, which are induced in a conductor placed at a constant distance from the probe. A commercially available product can be used as is for measuring eddy currents.

By the way, since the eddy current of a 1ffi film is proportional to its electrical resistance as described above, the electrical resistance can be determined from the output of the eddy current detector. The conductive film 2 may have a conductive thin film formed on either the upper surface or the lower surface of the film of the substrate. The substrate film of the conductive film may be transparent or opaque, and the material of the substrate film may be any plastic film.
Usually its thickness is between 1 μTrL and 1 mm.

The distance between the eddy current detectors 1a and 1b and the conductive film 2,
That is, the detection distance is usually 0.1 m/m to 10 TrL/
m, but the detection distance is small and the culm measurement accuracy is high. When measuring with one eddy current detector, as the conductive film 2 vibrates while running, the gap between the eddy current detector and the conductive film changes, causing a measurement error. However, in the present invention, one eddy current detector 1 is provided on each side of the conductive film 2.
a, 1b are arranged opposite to each other at a certain distance, and the eddy current detector 1a
, 1b are averaged, so the influence of vibration of the conductive film 2 is removed as described below.

That is, by photographing the conductive film 2, when the conductive film 2 approaches the eddy current detector 1a on the upper surface side, the detection output of A changes to the positive side, while the detection output of eddy current detector 1b on the lower surface side changes to the positive side. Since the output of 2 fluctuates toward the minus side by the distance of the conductive film 2, by adding both outputs, the fluctuations due to film vibration can be mutually canceled out, and the influence of the film vibration can be canceled out.

Furthermore, the magnetic flux density of the alternating current magnetic field is doubled by excitation of both hot current detectors 1a and 1b, and both hot current detectors 1a and lb
The output is further doubled by adding the output of
In the end, it is possible to obtain four times the detection sensitivity.

These two effects significantly increase the accuracy of characteristic measurement and enable stable measurement. In view of this effect, it is preferable that both hot current detectors 1a and 1b have the same characteristics.

FIG. 2 shows an example of the above-mentioned measurement circuit, including an eddy current detector 1a,
After the detection signal 1b is amplified by an amplifier 4, it is subjected to arithmetic processing by an average calculation device 5, and an electric resistance value is indicated on an indicator 6.

FIG. 3 shows an example in which eddy current detectors 1a and 1b are arranged facing each other on an integrated U-shaped support member 7, and eddy current detectors 1a and 1b arranged facing each other on a conductive film 2 are mounted on the same support member 7. , two eddy current detectors 1a, Ib due to vibration etc.
The relative positions of the two do not change. Of course it's all in one piece lr
If available, it can be not only U-shaped but also other shapes. In short, any shape may be used as long as the relative positions of the two eddy current detectors 1a and 1b can be fixed.

The averaging device 5 may be of any type as long as it can add the outputs of the eddy current detectors 1a and 1b, and a linearizer may be added as necessary depending on its characteristics.

Also, a recorder or a printer may be used instead of the indicator 6.

Furthermore, although this embodiment is an example in which the present invention is applied to an inspection device for quality control of conductive films, the present invention can be applied to conventionally known methods such as vapor deposition, sputtering, and ion plating.
It can also be applied to detecting the characteristics online when forming a conductive thin film on a substrate using this method, and controlling it by building a food pack circuit.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention, FIG. 2 is a block diagram of the measuring circuit of the embodiment, and FIG. 3 is a schematic side view of another embodiment of the measuring bed. 1a, 1b: Eddy current detector, 2: Conductive film, 3:
Transfer roll, 4: Multiplier, 5: Average calculator, 6: Indicator, 7: Indicator member Patent applicant: Teijin Co., Ltd. Teijin Engineering Co., Ltd.

Claims (1)

[Claims] 1. Consists of a pair of eddy current detectors arranged oppositely at a predetermined interval, and a calculation means for averaging the outputs of the eddy current detectors, and a conductive film is placed between the eddy current detectors. A device for measuring characteristics of a conductive film, characterized in that measurement is performed by positioning the conductive film. 2. The characteristic measuring device according to claim 1, wherein the eddy current detectors are arranged facing each other on the same support member.