JPH02221877A - Method for inspecting ic card - Google Patents

Abstract

PURPOSE:To easily perform inspection without flawing the panel surface of the IC card even if an insulator is provided on the surface by inserting the IC card into between flat plate electrodes and measuring the electrostatic capacity between the flat plate electrodes. CONSTITUTION:When the IC card 1 is inspected, the couple of flat plate electrodes 8 and 9 which face each other at an interval and an electrostatic capacity meter 10 which measures the electrostatic capacity between the flat plate electrodes 8 and 9 are used. Then the IC card to be inspected is inserted into between the flat plate electrodes 8 and 9 and the electrostatic capacity between the flat plate electrodes 8 and 9 is measured. Then whether the couple of conductive panels mounted on the top and reverse surface of the IC card are conductive is inspected according to the measured electrostatic capacity value. Consequently, the inspection is performed by the difference between the electrostatic capacity values when the couple of panels mounted on the top and reverse surfaces of the IC card are conductive and not conductive, so the electrodes need not be brought into contact with the top and reverse panels of the IC card and the inspection is enabled even when insulators are provided on the panel surfaces.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an IC card inspection method, and more specifically, to a method for inspecting continuity/non-continuity between a pair of panels attached to the front and back of an IC card. Concerning the method.

[Prior Art] Generally, as shown in FIG. 4, an IC card 1 includes a frame 2 made of resin, a panel 3 on the front side, a panel 4 on the back side, an IC 5, a wiring board 6, and both panels. 3.4 and a conductor 7 that electrically connects them.

In this IC card I, in order to prevent the IC5 inside the card from malfunctioning or being destroyed due to the effects of static electricity or electromagnetic fields, the IC5 is placed between the panels 3 and 4 made of conductive material such as metal. It has a structure in which the mounted wiring board 6 is sandwiched therebetween.

Furthermore, since the panels 3.4 need to be at the same potential, they are connected by a conductor 7 to ensure electrical continuity.

Conventionally, in order to test for continuity or non-continuity between the two panels 3.4 of such an IC card 1, the method shown in FIG. 5 is used.

That is, the positive electrode 2 is applied to one panel 3 of the IC card 1, and the negative electrode 12 is applied to the other panel 4, a voltage is applied between the picture electrodes 11 and 12, and the current flowing through the ammeter 14 is measured. , conduction or non-conduction is determined based on the measured value.

Note that since the conductor 7 is normally located inside the IC card 1, it is impossible to visually inspect it from the outside of the IC card 1.

[Problems to be Solved by the Invention] In such a conventional inspection method, it is necessary to bring each electrode 11.12, which has a relatively sharp tip, into contact with a part of each of the front and back panels 3.4. , may damage the surface of the panel 3.4, and furthermore, if the surface of the panel 3.4 is coated with insulating material by silk printing or the like, there are problems such as difficulty in inspection. .

The present invention has been made in view of the above points, and includes
Without damaging the panel surface of the C card, and
The purpose is to enable easy inspection even when an insulating material is applied to the surface.

[Means for Solving the Problems] In the inspection method of the present invention, in order to achieve the above object,
Prepare in advance a pair of flat plate electrodes facing each other with an interval and a capacitance meter that measures the capacitance between the flat plate electrodes, and insert an IC card between the flat plate electrodes to measure the static capacitance between the flat plate electrodes. Measure the capacitance, and based on the measured capacitance value,
It is designed to inspect continuity/non-continuity between a pair of conductive panels attached to the front and back of the Moeki C card.

[Function] According to the above configuration, the inspection is performed based on the difference in capacitance value between when there is continuity between the pair of panels attached to the front and back of the IC card and when there is no continuity. Unlike the conventional example, there is no need to contact the electrodes to the front and back panels of the IC card, and inspection can be performed even when the panel surface is coated with an insulating material.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram for explaining an inspection method according to an embodiment of the present invention. Note that the configuration of the IC card 1 to be inspected is the same as that of the conventional example shown in FIG. 4, so a description thereof will be omitted.

When inspecting the IC card 1, a pair of flat electrodes 8.9 facing each other with an interval and a capacitance meter 10 for measuring the capacitance between the flat electrodes 8.9 are prepared in advance.

Next, an IC card to be tested is inserted between the flat electrodes 8.9, and the capacitance between the flat electrodes 8.9 is measured.

Between the flat electrodes 8 and 9, as shown in FIG. 2(A),
When an IC card 1 with non-conductivity between the front and back panels 3 and 4 is inserted, the equivalent circuit is shown in Fig. 2 (B),
The combined capacitance Ca is expressed by equation (1).

1 / Ca = 1 / Ct + 17 Ct +
1/C3 (1) Here, CI is the capacitance between the flat plate electrode 8 and the panel 3, C6 is the capacitance between the panels 3.4, and C1 is the static capacitance between the panel 4 and the flat plate electrode 9. It is the capacitance.

On the other hand, when an rC card l is inserted between the flat electrodes 8.9, as shown in FIG. 3(A), the front and back panels 3.4 are electrically connected by the conductor 7. 4
The capacitance C1 between them can be ignored, and the equivalent circuit in this case can be expressed as shown in FIG. 3(B). Therefore, the combined capacitance C when there is continuity between panels 3 and 4
b is expressed by the formula (2% formula % If formula (1) is transformed, Ca ” (C + Ct Cs ) / (Ct Cy +
C+ C3+ C+ Ct ), and by transforming equation (2), we get Cb = (CICs) / (C+ + C3).

Here, if C2 takes a very small value compared to C+ and Cs, Ca < Cb (3).

Generally, the capacitance C between parallel plate electrodes is C=εA/
It can be expressed as d.

Here, ε is the dielectric constant, A is the area of the flat electrodes, and d is the distance between the flat electrodes.

Therefore, assuming that the permittivity ε and electrode area A of c, , c, , and C3 are the same, the capacitance is defined only by the distance d. Now, the distance between panels 3° and 4 is
The distance between the panel 3 and the flat electrode 8 and the distance between the panel 4 and the flat electrode 9
If it is sufficiently large compared to the distance between, then c, > ct and c, > c.

holds true, that is, C1 takes a very small value compared to C, , C3.

Therefore, the above equation (3) holds true, and a difference in capacitance is recognized between when the panels 3 and 4 are electrically connected and when they are not electrically conductive, making it possible to make a determination.

Normally, the surface of the panel 3.4 is printed, etc., so in actual inspection, it is necessary to
Insert the C card 1 and measure the capacitance between the flat plate electrodes 8.9 using the capacitance meter 10. If the previously measured value of cb is actually measured, it is determined that the panel 3.4 is conductive. However, if the value of Ca measured in advance is actually measured, it is determined that the panel 3.4 is not conductive.

[Effects of the Invention] As described above, according to the present invention, by inserting an IC card between the flat electrodes and measuring the capacitance between the flat electrodes, conduction/non-conduction between the front and back panels of the IC card can be determined. Since the inspection can be performed without directly contacting the electrodes to the front and back panels of the IC card, the front and back panels will not be damaged. Moreover, even if the front and back panels are coated with insulators, the inspection can be easily performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram for explaining the inspection method of an embodiment of the present invention, Fig. 2 is a configuration diagram and its equivalent circuit diagram when there is no conduction between panels 3 and 4, and Fig. 3 is a panel FIG. 4 is a cross-sectional view of an IC card, and FIG. 5 is a schematic diagram for explaining a conventional testing method. ■...IC card, 3.4...Panel, 8.9...
- Flat electrode, lO...capacitance meter. Figure 1

Claims (1)

[Claims] (1) Prepare in advance a pair of flat plate electrodes facing each other with an interval and a capacitance meter that measures the capacitance between the flat plate electrodes, insert an IC card between the flat plate electrodes, and measure the capacitance between the flat plate electrodes. Measure the capacitance of the IC card, and based on the measured capacitance value, determine the continuity between the pair of conductive panels attached to the front and back of the IC card.
An IC card inspection method characterized by inspecting non-conductivity.