Registers – Records – Conductive
Reexamination Certificate
2001-02-28
2004-07-27
Lee, Michael G. (Department: 2876)
Registers
Records
Conductive
C235S441000
Reexamination Certificate
active
06766959
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an information card, which is typically, but not exclusively, a PC card, and to a card shaped casing for such an information card.
2. Description of the Related Art
Conventionally, information cards are commonly used for adding new functions or increasing functionality of information processing devices such as personal computers (PC), personal digital assistants (PDAs) and other communication devices. The information cards are constructed by installing various electronic components and electronic circuits in a card shaped casing. With regard to the information cards for PCs, PC cards that adhere to standards according to the Personal Computer Memory Card International Association (PCMCIA) or the Japan Electronic Industry Development Association (JEIDA) are generally used. There are two types of PC cards including a first type for 16 bit bus width, and a second type which follows the CardBus standards, is for 32 bit bus width. Although the two types of PC cards differ from each other with respect to, for example, whether or not they require ground plates, or other features, the constructions thereof are basically the same. The basic construction of a conventional PC card is shown in
FIGS. 5 and 6
.
With reference to
FIG. 5
, a PC card includes a rectangular and flat frame
10
, a front panel
12
, and a back panel
14
. The frame
10
is generally constructed of a resin, and the front panel
12
and the back panel
14
are generally constructed of metal plates. Various electronic components and electronic circuits (printed patterns) are mounted or formed on a printed board
16
, which is disposed in a space surrounded by the frame
10
, the front panel
12
, and back panel
14
. The frame
10
defines the side surfaces of this space, and the front panel
12
and the back panel
14
defines the front and the back surfaces of this space. The electronic components and the electronic circuits on the printed board
16
are connected to an external device via a front connector
18
or via a back connector
20
provided in the frame
10
. The front connector
18
is disposed at one end of the PC card that is first inserted into a card-receiving slot, and the back connector
20
is disposed at the other end of the PC card. For example, with respect to memory cards, memory cells and memory circuits provided on the printed board
16
are connected to devices inside personal computers via the front connector
18
. In this case, the back connector
20
may be omitted. With respect to modem cards, LAN cards, and other types of cards, the front connector
18
is required for connecting the card to the devices inside personal computers, and the back connector
20
is also required for connecting the card to external wirings.
The front panel
12
and the back panel
14
are fixed to the frame
10
by, for example, thermocompression bonding. With reference to
FIG. 6
, the front panel
12
is constructed by forming an insulating layer
24
on an inwardly facing surface of a stainless steel plate
22
that is arranged to oppose the printed board
16
, and by forming an adhesive layer
26
on the insulating layer
24
. The back panel
14
is constructed in a similar manner. The front panel
12
and the back panel
14
are first aligned against the frame
10
in which the printed board
16
is disposed, and then the process of thermocompression bonding is performed. Accordingly, the front panel
12
and the back panel
14
are fixed to the frame
10
. The insulating layer
24
insulates the electronic components and the electronic circuits on the printed board
16
from the front panel
12
and the back panel
14
. In addition, the stainless steel plates are included in the front panel
12
and the back panel
14
, and the grounded lines included in the printed board
16
are connected thereto. Accordingly, the mechanical strength of the PC card is ensured, and the electronic components and the electronic circuits are electromagneticaly shielded from the exterior of the PC card.
As described above, two panels (the front panel and the back panel) are used in the conventional PC card, and each panel includes a plate constructed of stainless steel or other metal having conductivity and rigidity, an insulating layer, and an adhesive layer. Thus, the construction is complex and the manufacturing cost is high. Accordingly, there are limits to reducing the number of components required for manufacturing the PC card, and to reducing the manufacturing cost.
To solve such problems, a method disclosed in Japanese Unexamined Patent Application Publication No. 6-320892 is useful, which will be referred to as a “published technique” in the following descriptions. In this published technique, a half of the frame that is located near the front panel is unitarily formed with the front panel, and the remaining half of the frame which is near the back panel is unitarily formed with the back panel. In addition, the front panel which is unitarily formed with the front half of the frame and the back panel which is unitarily formed with the back half of the frame are constructed of a resin. Accordingly, panels constructed of metal are not used. When this technique is applied to PC cards, the number of components and the manufacturing costs are reduced compared to the conventional technique described with reference to
FIGS. 5 and 6
.
In the above-described published technique, however, the shapes and the constructions of the front panel and the back panel are complex compared to the conventional technique, since each panel is unitarily formed to define a half of the frame. According to the published technique, two members (the front panel which is unitarily formed with the front half of the frame and the back panel which is unitarily formed with the back half of the frame) must be prepared, each of which has a complex shape and construction. Thus, in the case in which the published technique is applied to a PC card, there is another limit to reducing the cost and difficulty of manufacturing the case.
In addition, since the front panel and the back panel are constructed of a resin, the structural strength is reduced and the electromagnetic shielding ability is degraded compared to the conventional technique, in which the front and the back panels are constructed of a metal. To increase the structural strength, the front and the back panels of the published technique are provided with plate-shaped projections on the surfaces that are arranged opposite to the printed board, so as to provide reinforcing members. However, such reinforcing members increase the complexity of the shapes and the manufacturing steps of the front and the back panels, and the reduction of the manufacturing cost is further impeded.
In addition, in the conventional technique shown in
FIGS. 5 and 6
, the front and the back panels constructed of a metal are adhered on the frame constructed of a resin. Thus, a material which is capable of fixing the metal and the resin is used for forming the adhesive layer
26
. In contrast, in the published technique, the front and the back panels are both constructed of a resin, and a double-sided adhesive tape is applied for fixing the front and the back panels to each other. Accordingly, when a manufacturer introduces the published technique in place of the conventional technique shown in
FIGS. 5 and 6
, the adhering method and the adhesive must also be changed. Thus, additional expenses for technological development and for obtaining manufacturing know-how is required.
SUMMARY OF THE INVENTION
In order to overcome the problems described above, preferred embodiments of the present invention provide an information card and a card shaped casing therefor which require few components, which are developed and manufactured at low cost, and in which the structural strength is sufficient and electromagnetic shielding is ensured.
To this end, a card shaped casing of a preferred embodiment of the present invention preferably includes
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Nguyen Kimberly D.
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