JP3358191B2 - How to strengthen IC card ground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EMI suppression technique, and more particularly, to a technique for suppressing EMI by an IC card mounted on a personal computer or the like.

[0002]

2. Description of the Related Art EMI (Electro Magnetic Interferenc)
e: Electromagnetic interference (hereinafter simply abbreviated as noise) The demand for suppression is increasing, but under such circumstances, noise suppression technology using communication equipment alone is realized within each manufacturer and satisfies the demand. However, once an IC card having a communication function is mounted on such a communication device and connected to a network or the like via a communication cable, noise emission from the communication cable as well as the IC card body may become a problem. .

[0003] When these countermeasures are taken, it is conventionally difficult to incorporate a countermeasure circuit inside the IC card itself, and the IC card itself is often made by another manufacturer. The current situation is to insert a ferrite core or the like for noise emission measures at the exit to prevent noise emission.

[0004] However, this ferrite core insertion is not preferable, and may be problematic from the viewpoint of appearance and workability, and the effect of suppressing noise emission is not so large.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an IC
It is an object of the present invention to provide means capable of effectively suppressing noise radiation in a state where the card is mounted on a device having an IC card connection port without directly taking measures against the card itself.

[0006]

In a so-called IC card to be mounted on a notebook personal computer or the like, the mounted I
In the case of a card that has an external communication line as well as the emission of the noise of the C card itself, a phenomenon that the noise component including the noise component from the personal computer itself is radiated to the outside via the communication line of the IC card occurs, which is a problem. May be.

This is due to the mechanism by which the impedance between the ground of the IC card and the ground of the personal computer body is high and the ground of the IC card is weak, so that it becomes unstable and noise components are radiated.

In order to reduce the impedance between the ground of the IC card and the ground of the personal computer, the present invention covers the periphery of the IC card with the ground of an electronic component substrate in the personal computer. In order to stabilize the ground of the IC card, the IC card case and the IC card body are brought into contact with low impedance to stabilize the ground of the IC card and suppress the emission of noise. I have.

[0009]

FIG. 1 is a three-dimensional view showing an embodiment of the present invention. FIG. 2 is a plan view of the present embodiment, and the numbers in the figure are the same as those in FIG. In FIG. 1, reference numeral 10 denotes an apparatus having an IC card connection port, 1 denotes a board in the apparatus, and 9 denotes an electronic device mounted on the board 1 in the apparatus.

Reference numeral 3 denotes an IC card case that covers the periphery of the IC card, and is constituted by a conductor such as a metal. In this case, a fixing screw 4 is used for a ground pattern 2 provided on the substrate 1 so as to be in contact with the entire surrounding area in consideration of low impedance.

Reference numeral 7 denotes an externally mounted IC card body (state before insertion), and reference numeral 8 denotes a connector cable for communicating with the outside. Two metal parts for grounding the internal circuit of the IC card are provided on both sides in the thickness direction of the IC card body 7.

A sliding piece 5 made of a conductor such as a metal for contacting the two side metal parts of the IC card body 7 is mounted on the IC card case 3 by means of a sliding piece mounting screw 6. 3 attached to both sides.

When the IC card body 7 is mounted on the in-apparatus substrate 1, the IC card body 7 is inserted through the opening of the IC card case 3 and housed in the IC card case 3, and the sliding piece 5 is attached to the IC card body 3. 7, two side metal portions (I
(Ground surface of the internal circuit of the C card).

Therefore, the ground of the substrate 1 in the device and the IC
Since the impedance between the grounds of the internal circuit of the card body 7 is reduced, the ground potential of the IC card body 7 becomes closer to the ground potential of the internal substrate 1 and the ground of the IC card is stabilized. As a result, noise emission from the IC card body 7 or its communication cable can be reduced.

Further, by providing the sliding piece 5 with an appropriate spring property, the contact between the sliding piece 5 and the IC card body 7 is further improved, and the ground of the in-device substrate 1 and the IC card body 7 The effect of keeping the impedance between the grounds of the internal circuit always low and constant can be expected.

In the above-described embodiment, I
Although the number of accommodated C-cards has been described as an example, measures for devices that can accommodate two or more IC cards are also described.
By applying similar measures to IC cards mounted adjacently,
A similar noise reduction effect can be obtained.

[0017]

According to the present invention, it is possible to effectively suppress the noise radiation from the IC card body and the cable to some extent without directly taking measures against the IC card itself, which is difficult to suppress noise radiation alone. I can do it. Also, I
With the ground stabilization by strengthening the ground of the C card, an additional effect of improving resistance to the influence of external noise such as static electricity can be obtained.

[Brief description of the drawings]

FIG. 1 is a three-dimensional view showing an embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 In-device board 2 Ground pattern 3 IC card case 4 Fixing screw 5 Sliding piece 6 Mounting screw 7 IC card main body 8 Connector cable 9 Electronic device mounted on in-device board 10 Device having IC card connection port

Claims (3)

(57) [Claims] (1)Substrate on which IC card connection terminals are arranged
And at least the upper surface of an IC card mounted on the substrate
And its periphery is fixed on the substrate so as to cover both sides.
IC card connection port with a closed IC card case
In the device that has The IC card case is made of a conductor such as a metal.
The ground pattern on the substrate
Are mounted so that they touch each other, and on both sides
I provided on both sides of the IC card mounted on the
Contact surface that contacts the ground metal part of the internal circuit of the C card
IC card connection port characterized by having
Equipment with 2. The contact card provided in the IC card case.
The contact surface is composed of a metal sliding piece with spring properties
2. The device having an IC card connection port according to claim 1, wherein: 3. An IC car according to claim 1 or claim 2.
Notebook PC with network connection port.