JP3191110B2 - IC memory card - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC memory card, and in particular, to an ESD (Electro
The present invention relates to an IC memory card capable of improving a withstand capacity (ro-Static Discharge).

[Conventional technology]

FIG. 2 is a cross-sectional view showing the structure of a conventional IC memory card. In FIG. 2, reference numeral 1 denotes a semiconductor memory device having a lead 1a;
Is a connector provided with a connector lead 2a and used for electrical connection with an external device. The semiconductor memory element 1 and the connector 2 are mounted on a wiring board 3 fixed to a molded frame 4 made of resin. Two conductive panels 5 are adhered to the molded frame 4 and the connector 2 with an adhesive (not shown), and the wiring board 3 is placed in a space formed by the molded frame 4 and the conductive panel 5. Are located. A resist layer 6 is formed on the inner surface of the conductive panel 5 by printing and applying a resist material having higher insulation resistance than air.
The inner surface is insulated by the resist layer 6. The resist layer 6 has many pinholes 7.

Hereinafter, a path of a discharge current when static electricity is applied to the conductive panel 5 in a state where a conventional IC memory card having such a structure is connected to an external device will be described. The phenomenon in which a discharge current flows due to the application of static electricity is seen, for example, when a charged hand contacts an IC memory card connected to an external device.

A resist layer 6 having a higher insulation resistance than air is provided on the inner surface of the conductive panel 5.
Since there are many pinholes 7 in the resist layer 6
Discharge occurs at an electrostatic voltage lower than the withstand voltage of the resist material. At this time, the path of the electrostatic discharge current is not constant,
Various routes are taken depending on the magnitude of the applied electrostatic voltage and the state of the pinhole 7 in the resist layer 6. Specifically, the discharge current passes through the inside of the semiconductor memory element 1 in the IC memory card, or passes through the wiring pattern of the wiring board 3 through the lead 1a of the semiconductor memory element 1, and the connector lead 2a of the connector 2 The discharge current flows into the external device via.

[Problems to be solved by the invention]

In the conventional IC memory card, when the static electricity is applied to the conductive panel 5, the discharge current flows as described above.
There is a problem that a malfunction or destruction of the semiconductor memory element 1 inside the IC memory card occurs.

As a conventional example similar to the present invention, Japanese Utility Model Application Laid-Open No.
No. 166, “Card-shaped recording device” (hereinafter referred to as a first conventional example) and Japanese Utility Model Laid-Open No. 1-62083, “IC card”
(Hereinafter, referred to as a second conventional example). In a first conventional example, a main body accommodating an IC circuit therein, conductive panels provided on a front surface portion and a rear surface portion of the main body, respectively, and the two conductive panels are electrically connected inside the main body. A connection member such as a spring. In the second conventional example, an insulating member is inserted between a conductive panel and an IC circuit portion, and a ground connection portion for establishing electrical continuity with a housing of the external device when connected to the external device. Is provided on the surface side of the conductive panel.

The present invention has been made in view of such circumstances, and provides an IC memory card that can flow a discharge current without causing malfunction or destruction of a semiconductor memory element when static electricity is applied to a conductive panel. The purpose is to:

[Means for solving the problem]

An IC memory card according to the present invention is an IC memory card including a wiring board on which a semiconductor memory element and a connector for electrical connection with an external device are mounted in a space formed by a frame and a conductive panel. The inner surface of the conductive panel is covered with an insulating layer, except for a portion on the wiring board that has the same potential as a ground terminal or a frame ground terminal of the external device and a grounding portion that is in proximity via air. It is characterized by being.

[Action]

In the IC memory card of the present invention, when static electricity is applied to the conductive panel, the same potential as that of the ground terminal or the frame ground terminal of the external device on the wiring board from the portion where the insulating layer is not provided. The discharge current flows to the ground terminal or the frame ground terminal of the external device via the part. As described above, in the IC memory card of the present invention, the path of the discharge current is limited to one path, and does not adversely affect the semiconductor memory element.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments.

FIG. 1 is a cross-sectional view showing the structure of an IC memory card of the present invention, in which 1 is a semiconductor memory element having leads 1a,
Reference numeral 2 denotes a connector having a connector lead 2a and used for electrical connection with an external device. The semiconductor memory element 1 and the connector 2 are mounted on a wiring board 3 fixed to a molded frame 4 made of resin. Molded frame 4 and connector 2
, Two conductive panels 5 are adhered by an adhesive (not shown), and the wiring board 3 is disposed in an internal space formed by the molded frame 4 and the conductive panels 5. .
An insulating layer 8 made of an insulating material having higher insulation resistance than air is provided on the inner surface of the conductive panel 5. Only the portion near the ground pin or the frame ground pin of the connector lead 2a is not provided with the insulating layer 8 and is a non-insulating region 9. Then, when a high voltage is applied to the surface of the conductive panel 5, dielectric breakdown occurs in the non-insulating region 9.

Hereinafter, a path of a discharge current when static electricity is applied to the conductive panel 5 with the IC memory card of the present invention having such a structure connected to an external device will be described. In the IC memory card of the present invention, static electricity is applied between the ground terminal or the frame ground terminal of the external device and the conductive panel 5. When the voltage of the applied static electricity exceeds the withstand voltage of air between the inner surface of the conductive panel 5 and the ground pin or the frame ground pin of the connector lead 2a, discharge occurs, and the conductive panel
5, The static discharge current flows into the ground terminal or the frame ground terminal of the external device via the non-insulated region 9, the ground pin or the frame ground pin. The path of this discharge current is limited to the above-described one path, and when the discharge current flows through such a path, the semiconductor memory element 1
Will not be adversely affected.

Although the non-insulating region 9 is provided above the connector lead 2a in the above embodiment, the non-insulating region 9 may be provided above the ground pattern of the wiring board 3.

The difference between the above-described conventional example and the present invention will be described.
The present invention does not require a special material such as a ground spring as in the first conventional example. Further, in the present invention, unlike the second conventional example, the current collecting panel and the external device are not electrically connected.

[Effect of the Invention] As described above, the IC memory card of the present invention covers the inner surface of the conductive panel facing the space formed by the frame and the conductive panel with the insulating layer, and this insulating layer is Since the ground terminal or the part on the wiring board having the same potential as the ground terminal or the frame ground terminal is removed at the grounding portion adjacent via air, static electricity is applied to the conductive panel in a state of connection to an external device. When this occurs, the discharge current due to this concentrates on the grounding portion not covered by the insulating layer, and passes through a portion on the wiring board close to the grounding portion to the ground terminal of the external device or the frame ground terminal. It flows along a path leading to, that is, a certain path that does not adversely affect the semiconductor memory element. Therefore, a malfunction or destruction of the semiconductor memory element does not occur, and a highly reliable card system can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of the IC memory card of the present invention,
FIG. 2 is a sectional view showing the structure of a conventional IC memory card. DESCRIPTION OF SYMBOLS 1 ... Semiconductor memory element, 2 ... Connector, 3 ... Wiring board, 4 ... Molded frame, 5 ... Conductive panel, 8 ...
... insulating layer, 9 ... non-insulating area In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. An IC memory card comprising a wiring board on which a semiconductor memory element and a connector for electrical connection with an external device are mounted in a space formed by a frame and a conductive panel. The inner surface of the external device is covered with an insulating layer, except for a portion for grounding that is close to a portion on the wiring board that has the same potential as a ground terminal or a frame ground terminal of the external device via air. And IC memory card.