IC card

IC card of the present invention consists of a frame including a rectangular bottom plate and a U-shaped side wall along the three edges of the bottom plate; a connector fixed to the open side of the frame with the U-shaped side wall; a board module at least one including printed-circuit boards with electronic components mounted thereon, combined with the connector, and inserted in the frame; and a metal panel for sealing off the board module inside the frame with the connector fixed thereto.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to an IC card, more particularly to 
a thinner IC card which accommodates more electronic components more 
compactly. 
2. Description of the Prior Art 
IC cards based on PCMCIA specification have been now widely used. 
FIG. 14 is a perspective view showing an external appearance of a 
conventional IC card. FIG. 15 is an exploded view of the IC card shown in 
FIG. 14. FIG. 16 is a cross section of the IC card shown in FIG. 14 cut 
along the plane XVI--XVI. 
In FIGS. 14-16, an IC card 50 includes a U-shaped frame 51 made of plastic 
for example, metal panels 52a and 52b, a connector 53, made of plastic for 
example, which has a plurality of terminals 54 insert-molded therein so as 
to protrude inside of IC card 50, and a printed-circuit board 55 with 
electronic components 56 mounted on both surfaces thereof. 
Inner tip ends of terminals 54 of connector 53 are formed so as to insert 
one side of board 55 along which a plurality of connecting tips are 
printed and, when inserted, electrically connect lines of board 55 with 
those of the external system, respectively. The combined connector 53 and 
printed-circuit board 55 are coupled with frame 51 so that the connector 
and the frame contain the printed-circuit board. Combined frame 51 and 
connector 53 containing printed-circuit board 55 connected to terminals 54 
of the connector are sandwiched between metal panels 52a and 52b through 
adhesive sheets 57a and 57b, respectively. 
Upon assembling an IC card as shown in FIGS. 14-16, printed-circuit board 
55, with electronic components mounted on it, is connected to connector 53 
by means of connector terminals 54, and then connector 53 is fit to frame 
51. Then adhesive sheets 57a and 57b are pasted to metal panels 52a and 
52b, respectively. Metal panels 52a and 52b are fixed, with heat and 
pressure, by means of adhesive sheets 57a and 57b, respectively, to frame 
51 combined with connector 53 and printed-circuit board 55 from the top 
and the bottom. In the process of assembling IC cards adhesive sheets 57a 
and 57b must be pasted to metal panels 52a and 52b in considerable 
precision. Further, the amount of heat and pressure required to fix the 
metal panels to the frame must also be controlled precisely. Thus, 
manufacturing conventional IC cards requires the greatest attention in the 
assembly process, which results in higher manufacturing cost. 
As increasingly more electronic components are mounted on a conventional IC 
card of a fixed size of 85.6 mm.times.54.0 mm.times.3.3 mm, for example, a 
multilayer printed-circuit board has been used to accommodate them. The 
structure of a multilayer printed-circuit board with electronic components 
mounted thereon and the mounting method are disclosed in Japanese Patent 
Laid-Open Publication HEI 3-280496. The structure disclosed in that 
publication includes stacked printed-circuit boards with common through 
holes in them and a plurality of electronic components which are inserted 
in each through hole and mounted on top of one another. Only "bonding" is 
allowed in this configuration, and an electronic component with a molded 
package cannot be mounted. Ordinary soldering such as reflow soldering 
cannot be used either. This structure does not allow printed-circuit 
boards to have electronic components initially mounted on them and then to 
be stacked on top of one another. 
SUMMARY OF THE INVENTION 
Therefore, one object of the present invention is to provide an IC card 
which accommodates more electronic components more compactly yet has a 
simpler structure thus giving rise to easier manufacturing at lower cost. 
The present invention provides an IC card comprising a frame including a 
substantially rectangular bottom plate and a U-shaped side wall along the 
three edges of the bottom plate; a connector fixed to the open side of the 
frame with the U-shaped side wall; a board module including at least one 
printed-circuit board with electronic components mounted thereon, combined 
with the connector, and inserted in the frame; and a metal panel for 
sealing the board module inside the frame with the connector fixed 
thereto. While a conventional IC card uses two metal panels this invention 
requires only one metal panel because the bottom plate of the frame, 
formed in one piece with the frame, can substitute for the bottom panel of 
the conventional IC card. The connector, combined with the board module, 
is fixed to the open side of the frame with the U-shaped side wall. After 
the board module is fixed to the frame, the metal panel seals the board 
module inside the frame combined with the connector. 
One embodiment of the present invention provides an IC card, wherein the 
board module comprises a first printed-circuit board with electronic 
components mounted thereon and a second printed-circuit board with 
electronic components mounted thereon, the second printed-circuit board 
being overlaid on top of the first printed-circuit board and connected 
therewith so that the mounting surfaces of the electronic components face 
in the same direction and the surface of second printed-circuit board with 
no electronic component mounted thereon faces the metal panel. The first 
and second printed-circuit boards, each having electronic components 
mounted on one surface, are overlaid on top of each other so that the 
surfaces with the electronic components mounted thereon face in the same 
direction. The board module is formed by electrically connecting the 
printed-circuit boards with each other. Then, the connector combined with 
the board module is fixed to the open side of the frame with the U-shaped 
side wall so that the surface of the board module with no electronic 
component mounted thereon faces the metal panel. 
Another embodiment of the present invention provides an IC card, wherein 
the metal panel is formed with a metal foil. The connector, combined with 
the board module, is fixed to the open side of the frame with the U-shaped 
side wall so that the surface of the second printed-circuit board with no 
electronic component mounted thereon faces the metal panel. The metal foil 
is pasted on the surfaces of the second printed-circuit board with no 
electronic component mounted thereon, the connector, and the frame in 
order to seal the board module inside the frame combined with the 
connector. 
A further embodiment of the present invention provides an IC card, wherein 
the second printed-circuit board includes through holes where the 
electronic components mounted on the first printed-circuit board are 
inserted so that when the first printed-circuit board is overlaid on the 
second printed-circuit board and brought into contact therewith, the 
electronic components mounted on the first printed-circuit board do not 
come into contact with the non-mounting surface of the second 
printed-circuit board. The board module is formed by bringing the first 
printed-circuit board into contact with the second printed-circuit board, 
with the first printed-circuit board overlaid on top of the second 
printed-circuit board so that the surfaces of both the printed-circuit 
boards with the electronic components mounted thereon face in the same 
direction. In this process each of the electronic components mounted on 
the first printed-circuit board is inserted into the corresponding through 
hole. Then, electrical and mechanical connections between the first and 
second printed-circuit boards are made. 
A still further embodiment of the present invention provides an IC card, 
wherein the first and second printed-circuit boards include bonding pads 
on the facing surfaces thereof at opposite positions so that the first and 
second printed-circuit boards can be connected by soldering the bonding 
pads. The first printed-circuit board is brought into contact with the 
second printed-circuit board with the first printed-circuit board overlaid 
on top of the second printed-circuit board so that the surfaces of both 
the printed-circuit boards with the electronic components mounted thereon 
face in the same direction. The printed-circuit boards are electrically 
connected by soldering the bonding pads formed on both the printed-circuit 
boards. 
A still further embodiment of the present invention provides an IC card, 
wherein the first and second printed-circuit boards include semicircular 
through holes at opposite positions along a side of said board module, so 
that the first and second printed-circuit boards can be connected by 
soldering each pair of corresponding semicircular through holes. The first 
printed-circuit board is brought into contact with the second 
printed-circuit board with the first printed-circuit board overlaid on top 
of the second printed-circuit board so that the surfaces of both the 
printed-circuit boards with the electronic components mounted thereon face 
in the same direction. The printed-circuit boards are electrically 
connected by soldering the semicircular through holes. 
A still further embodiment of the present invention provides an IC card, 
wherein the first and second printed-circuit boards are formed from one 
single printed-circuit board, one surface of which forms connecting 
surfaces for the first and second printed-circuit boards, and the other 
surface of which includes a folding portion with a slit along the boundary 
of the first and second printed-circuit boards, the board module being 
formed by folding the single printed-circuit board along the folding 
portion so that the connecting surfaces of the first and second 
printed-circuit boards are in contact with each other. The first and 
second printed-circuit boards are first formed on a single common 
printed-circuit board having a slit cut halfway along the boundary of the 
first and second printed-circuit boards. The single board is then folded 
along the slit so that the connecting surface of the first printed-circuit 
board is brought into contact with the same connecting surface of the 
second printed-circuit board to form the board module after electrically 
connecting the printed-circuit boards with each other. 
A still further embodiment of the present invention provides an IC card, 
wherein said single printed-circuit board has wiring patterns on said 
connecting surface and said folding portion includes a slit formed by 
cutting said single printed-circuit board halfway so that the wiring 
patterns are intact. The first and second printed-circuit boards are first 
formed on a single common printed-circuit board. Wiring patterns are 
formed on one surface of the single printed-circuit board to make the 
connecting surfaces for the first and second printed-circuit boards. The 
slit is formed by cutting halfway through the other surface of the single 
printed-circuit board with the wiring patterns intact. Thus the first and 
second printed-circuit boards of the board module are electrically 
connected by the wiring patterns.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The embodiments of the present invention are described with reference to 
accompanying drawings. 
Embodiment 1 
FIG. 1 is a perspective view showing an external appearance of the IC card 
of Embodiment 1 of the present invention. FIG. 2 is an exploded view of 
the IC card shown in FIG. 1. FIGS. 3 and 4 are cross sections of the IC 
card shown in FIG. 1 cut along the plane III--III, and the plane IV--IV, 
respectively. 
The IC card 1 shown in FIGS. 1-4 comprises a frame 2 made of a material 
such as plastic, a first printed-circuit board 3 with various chips, such 
as bare chips, mounted on one surface of the board, a second 
printed-circuit board 4 with electronic components, with molded packages, 
also mounted on one surface of the board, first printed-circuit board 3 
and second printed-circuit board 4 forming a board module 5, a connector 6 
which is connected with board module 5 and fitted and fixed to frame 2, 
and a metal panel 7 for sealing board module 5 inside the frame connected 
with connector 6. Hereinafter a bare chip 8 is taken as an example of the 
chips mentioned above, and a molded IC 9 is taken as an example of the 
aforementioned electronic components with the molded packages. First 
printed-circuit board 3, second printed-circuit board 4, and board module 
5 all have dimensions and structures which fit in frame 2. 
Frame 2 of the above configuration, as shown in FIG. 2, comprises a 
substantially rectangular bottom plate portion 10, a U-shaped side wall 
portion 11 along the edges of bottom plate portion 10, and fitting 
portions 12 at the ends of the opposite side walls for fitting to 
connector 6. Typically frame 2 is made of plastic and can be made in one 
piece. Side wall portion 11 has, on its inner side, a step 13 which holds 
the edges of board module 5 and secures the module inside frame 2. The 
inner sides of fitting portions 12 have a teeth-like shape. 
Each bare chip 8 is mounted at an appropriate place on one surface of first 
printed-circuit board 3 by flip chip bonding. Second printed-circuit board 
4 has a through hole 14 at a place corresponding to each bare chip 8 so 
that the bare chips mounted on the first printed-circuit board can go into 
the holes. Each IC 9 is mounted on a surface (referred to hereinafter as 
the mounting surface) of second printed-circuit board 4 so that the 
package of IC 9 covers each through hole 14. The surface of first 
printed-circuit board 3, on which electronic components are mounted 
(referred to hereinafter as mounting surface) and the non-mounting surface 
of second printed-circuit board 4 each have bonding pads on them at 
corresponding positions. 
Next, each bare chip 8 on first printed-circuit board 3 is inserted into 
corresponding through hole 14 on second printed-circuit board 4, and first 
printed-circuit board 3 is overlaid on second printed-circuit board 4 so 
that bonding pads 15 on first printed-circuit board 3 are overlaid on 
corresponding bonding pads 16 on second printed-circuit board 4. Solder 
has been placed on either bonding pads 15 or 16. Combining the overlaid 
first printed-circuit board 3 with second printed-circuit board 4 by means 
of pressure and heat melts the solder and connects pads 15 and 16 
together. Thus first printed-circuit board 3 and second printed-circuit 
board 4 are bonded together to form board module 5. 
Connector 6 comprises a connector housing 18 made of plastic and 
insert-molded connecting terminals 17, for power supply, ground, signals, 
and so on, in which pins of an external system are inserted. Board module 
5 is connected to connector 6 by soldering connecting terminals 17 to the 
mounting surface of second printed-circuit board 4. Connector housing 18 
includes fitting portions 19 which have shapes corresponding to fitting 
portions 12 of frame 2. Matching fitting portions 19 with fitting portions 
12 fixes connector 6 to frame 2. The height of connector 6 is designed to 
be the same as the height of side walls 11 of frame 2 so that the 
combination of the connector and the frame will have a uniform thickness. 
It must be noted that second printed-circuit board 4 of board module 5 
should face bottom plate portion 10 of frame 2 and sit on step 13. Now, 
board module 5 is securely contained in frame 2. When connector 6, 
combined with module 5, is fixed with frame 2, the non-mounting surface of 
first printed-circuit board 3 of board module 5 is almost coplanar with 
the top of side wall 11 and the top surface of connector housing 18. 
Metal panel 7 comprises a metal foil, one side of which is coated with 
adhesive. The metal panel is pasted on the non-mounting surface of first 
printed-circuit board 3, on the top of side wall 11, and on the top 
surface of connector housing 18, which are almost coplanar, in order to 
seal off board module 5 from external noise and an electrostatic field. As 
mentioned earlier, bare chips are inserted into through holes 14. 
FIG. 5 shows how to assemble electronic components on first printed-circuit 
board 3. FIG. 6 shows how to assemble electronic components on second 
printed-circuit board 4. FIG. 7 shows a cross section of combined 
connector 6 and board module 5. FIG. 8 is a plan view of frame 2. FIG. 9 
shows a plan view of connector 6 combined with board module 5 and fixed 
into frame 2. The process for manufacturing IC cards will be described 
with reference to FIGS. 5-9. In FIG. 6 only one through hole 14 is shown 
for easy description and understanding, but the printed-circuit board can 
have more through holes on it depending on the application. 
First, as shown in FIG. 5, bonding pads 15 are provided and then bare chips 
8 are mounted at appropriate positions on the mounting surface of first 
printed-circuit board 3. At the same time, as shown in FIG. 6, through 
holes are formed on second printed-circuit board 4 at positions 
corresponding to bare chips 8 mounted on first printed-circuit board 3. 
Bonding pads 16 are also provided on the non-mounting surface of second 
printed-circuit board 4 at the positions corresponding to bonding pads 15 
of first printed-circuit board 3. ICs 9 are then mounted on the mounting 
surface of second printed-circuit board 4 to cover through holes 14. 
Solder is placed on either bonding pads 15 or 16. 
Next, first printed-circuit board 3 is overlaid on second printed-circuit 
board 4 so that the mounting surface of first printed-circuit board 3 is 
in contact with the non-mounting surface of second printed-circuit board 
4. In this process each bare chip 8 mounted on first printed-circuit board 
3 is inserted into its corresponding through hole 14 of second 
printed-circuit board 4, and bonding pads 15 are placed on top of bonding 
pads 16. Pressure and heat are applied to the boards to solder bonding 
pads 15 to bonding pads 16 in order to form board module 5. Then, inwardly 
protruded portions of terminals 17 of connector 6 are soldered to the 
predetermined positions of second printed-circuit board 4. 
Next, the edges of the mounting surface of second printed-circuit board 4 
are pasted on step 13 of frame 2 in FIG. 8 while fitting portions 19 of 
connector 6 are fitted into fitting portions 12 of frame 2 to combine 
connector 6 with frame 2, so that, as shown in FIG. 9, the non-mounting 
surface of first printed-circuit board 3, the top of side wall 11 of frame 
2, and the top surface of connector housing 18 become almost coplanar. To 
complete an IC card, metal panel 7 is pasted on the non-mounting surface 
of first printed-circuit board 3, on the top of side wall 11, and on the 
upper surface of connector housing 18. 
Thus, the IC card of Embodiment 1 includes board module 5 formed with first 
printed-circuit board 3 and second printed-circuit board 4 which are 
overlaid one on top of the other and combined, in contact with each other, 
by soldering bonding pads on both boards. In the above process bare chips 
8, mounted on first printed-circuit board 3, are inserted into 
corresponding through holes 14 of second printed-circuit board 4. This 
structure allows electronic components with a molded package, which are 
easy to mount, to be used and facilitates the electrical and mechanical 
connections of two printed-circuit boards. The thickness of board module 5 
is about the same as the aforementioned conventional printed-circuit board 
having electronic components mounted on both sides thereof. Since the 
mounting surfaces of first and second printed-circuit boards 3 and 4 face 
in the same direction, no mounting surface of either printed-circuit board 
is exposed to the outside when board module 5 is fitted into frame 2. 
Accordingly, the metal plate of the conventional IC card can be replaced 
by a thin metal foil as in this embodiment. 
Since frame 2 with bottom plate 10 can be formed in one piece using resin, 
only one metal plate is necessary in this embodiment while the 
conventional IC card requires two metal plates. Further, the IC card of 
the present embodiment can be assembled from one side while the 
conventional IC card needs to be assembled from both sides. Thus, the 
structure of the present embodiment increases the packaging density of 
electronic components mounted on an IC card, reduces the number of metal 
panels to be required, permits the use of a less expensive material for 
the metal panel, facilitates the assembly processes of IC cards, and hence 
reduces the production cost of IC cards. 
Embodiment 2 
FIG. 10 shows bonding pads 15 and 16 for connecting first printed-circuit 
board 3 to second printed-circuit board 4 of Embodiment 1 as described 
above. As seen from FIG. 10, it is impossible to check by sight the 
quality of the soldering after the bonding pads are soldered during the 
process of Embodiment 1. In order to resolve this problem each of the two 
printed-circuit boards of the IC card of Embodiment 2 of the present 
invention includes semicircular through holes along the edge of the board 
as shown in FIG. 11, by which the two boards are combined. It is noted 
that the shape of the bonding pads shown in FIG. 10 does not have to be 
circular, but can be of any shape as far as soldering is done without any 
problem. 
FIG. 11 shows the semicircular through holes used to combine first 
printed-circuit board 31 with second printed-circuit board 32 of the IC 
card of Embodiment 2 of the present invention. First printed-circuit board 
31 is identical to first printed-circuit board 3 of Embodiment 1 except 
that semicircular through holes 33 of first printed-circuit board 31 
substitute for bonding pads 15 of first printed-circuit board 3. 
Similarly, second printed-circuit board 32 is identical to second 
printed-circuit board 4 of Embodiment 1 except that semicircular through 
holes 34 of second printed-circuit board 32 substitute for bonding pads 16 
of second printed-circuit board 4. Since Embodiment 2 is the same as 
Embodiment 1 except for these differences, only the differences will be 
described in detail with reference to FIG. 11. 
As shown in FIG. 11, one or more semicircular through holes 33 are made 
along one or more edges of first printed-circuit board 31. Semicircular 
through holes 34 are made on second printed-circuit board 32 in positions 
corresponding to semicircular through holes 33 on first printed-circuit 
board 31. Next, first printed-circuit board 31 is overlaid on second 
printed-circuit board 32 so that the mounting surface of first 
printed-circuit board 31 is in contact with the non-mounting surface of 
second printed-circuit board 32. In this process each bare chip 8 mounted 
on first printed-circuit board 31 is inserted into its corresponding 
through hole 14 of second printed-circuit board 32, and semicircular 
through holes 33 are lined up with corresponding semicircular through 
holes 34. Semicircular through holes 33 and 34 are soldered by dipping in 
a solder bath to form a board module. 
Thus, the IC card of Embodiment 2 includes a board module formed with first 
printed-circuit board 31 and second printed-circuit board 32 which are 
overlaid one on top of the other and combined, in contact with each other, 
by soldering semicircular through holes 33 and 34. In the above process 
bare chips 8 mounted on first printed-circuit board 31 are inserted into 
corresponding through holes 14 of second printed-circuit board 32. In 
addition to the advantages of the IC cards of Embodiment 1, the structure 
of Embodiment 2 facilitates the process of the electrical and mechanical 
connections of first printed-circuit board 31 with second printed-circuit 
board 32 because the printed-circuit boards are combined with semicircular 
through holes 33 and 34 dipped in a solder bath. This structure also 
allows for easier sight inspection of the quality of the soldering. These 
advantages further reduce the cost of the production of IC cards and 
improves their reliability. 
Embodiment 3 
The first and second printed-circuit boards in Embodiments 1 and 2 are 
prepared separately. However, those boards can be prepared from a single 
board. The IC card made in this way is referred to as Embodiment 3 of the 
present invention. 
FIG. 12 is a plan view of the first and second printed-circuit boards 
prepared on a single printed-circuit board. FIG. 13 is a side view of the 
printed-circuit board shown in FIG. 12. The IC card of Embodiment 3 is 
identical to Embodiments 1 and 2 except for the printed-circuit boards. 
The description of Embodiment 3 of the present invention is given with 
reference to FIGS. 12 and 13. The like reference numbers in FIGS. 12, 13 
and previous drawings indicate the same elements and the description of 
them will not be given. 
In FIGS. 12 and 13, printed-circuit board 40 comprises first 
printed-circuit board 41 and second printed-circuit board 42. The surface 
that includes wiring patterns to connect first printed-circuit board 41 
with second printed-circuit board 42 electrically is referred to as the 
connecting surface while the other surface is referred to as the 
non-connecting surface. Bare chips 8 are mounted at designated positions 
on connecting surface 43 of first printed-circuit board 41 by flip chip 
bonding. Second printed-circuit board 42 includes through holes 14 to 
accommodate bare chips 8 mounted on first printed-circuit board 41 at 
positions corresponding to those chips. ICs 9 are mounted on 
non-connecting surface 44 of second printed-circuit board 42 so that the 
package of each IC covers through holes 14. 
At the boundary of first printed-circuit board 41 and printed-circuit board 
42 on the non-connecting surface 44 there is a folding slit 45, shallow 
enough not to break the wiring patterns, for folding the printed-circuit 
board 40. Printed-circuit board 40 is folded along folding slit 45 and 
first printed-circuit board 41 is overlaid on second printed-circuit board 
42 with bare chips 8, mounted on first printed-circuit board 41, inserted 
into their corresponding through holes 14 on second printed-circuit board 
42. 
Adhesive has been applied to all connecting surface 43 of first and second 
printed-circuit boards 41 and 42 except for the portions where bare chips 
8 are mounted. Accordingly, when printed-circuit board 40 is folded, first 
and second printed-circuit boards 41 and 42 are pasted together with the 
electronic connection and the wiring intact, and a board module is now 
formed. 
Thus, the IC card of Embodiment 3 includes a board module formed with first 
printed-circuit board 41 and second printed-circuit board 42. Those 
printed-circuit boards are first formed on single common printed-circuit 
board 40 having a slit at the boundary between first printed-circuit board 
41 and second printed-circuit board 42; they are then folded along the 
slit so that connecting surface 43 of first printed-circuit board 41 is in 
contact with connecting surface 43 of second printed-circuit board 42; and 
then they are pasted together. In the above process bare chips 8 mounted 
on first printed-circuit board 41 are inserted into corresponding through 
holes 14 on second printed-circuit board 42. 
In addition to the advantages of the IC cards of Embodiments 1 and 2, the 
structure of the IC card of the present embodiment has neither bonding 
pads nor semicircular through holes and allows the first and second 
printed-circuit boards to be formed from one single printed-circuit board. 
The structure, therefore, facilitates the design of the printed-circuit 
boards and reduces the production cost of the printed-circuit boards 
because folding the printed-circuit board along the slit can easily be 
done mechanically and because the electrical connection remains intact 
since the wiring patterns do not break in the folding process. 
In Embodiments 1, 2, and 3, first printed-circuit boards 3 and 31, second 
printed-circuit boards 4 and 32, and printed-circuit board 40 may be 
formed on a laminated board. In this case printed-circuit board 40 of 
Embodiment 3 has wiring patterns on the first layer to make an electrical 
connection between first printed-circuit board 41 and second 
printed-circuit board 42. Folding slit 45 is formed by cutting the 
printed-circuit board halfway and leaving the first layer intact. 
While, in addition to the above embodiments, there are various 
modifications of the present invention, it should be understood that the 
above embodiments have been presented by way of examples only and not 
limitation. Thus, the breadth and scope of the present invention should be 
defined only in accordance with the claims described in Scope of claims. 
Although the present invention has been fully described in connection with 
the preferred embodiments thereof with reference to the accompanying 
drawings, it is to be noted that various and modifications are apparent to 
those skilled in the art. Such changes and modifications are to be 
understood as included within the scope of the present invention as 
defined by the appended claims unless they depart therefrom.