JP2003110202A - Card-type electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a card-type electronic equipment with which bending of a printed board is prevented when the board is made extremely thin, and resistance to bending strength is improved. SOLUTION: Dummy patterns DP, DP,... are disposed in dead spaces on one surface 20B of a board 2, in which new patterns can be formed by avoiding circuit patterns Pb, Pb,..., which are to serve as signal paths. Furthermore, a part of the circuit patterns, which are to serve as acceptable signal paths are made wider, and the pattern mount area of this surface 20B of the board is made almost equal to the pattern mount area of the other surface of the board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a card type electronic device constructed by using a double-sided printed circuit board.

[0002]

2. Description of the Related Art In a card type device such as a small memory card, if the size of the card is further reduced, it is necessary to reduce the thickness of the card to the limit. However, when the thickness of the card is reduced, there is a problem of resistance to bending strength,
In particular, when the printed circuit board (printed circuit board), which is the main part of the card, is made as thin as possible, the board warps during the heat treatment process such as reflow, and due to this warp,
There is a problem in yield due to defective soldering of pads and the like, and further defective external dimensions.

[0003]

As described above, in order to further miniaturize the card type electronic equipment, when the printed circuit board which is the main part of the card is made extremely thin, the heat treatment process such as reflow is conventionally performed. There is a problem in that a warp occurs in the substrate, and this warp causes inconveniences such as defective soldering of the pad portion and the like, and further defective external dimensions.

The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a card-type electronic device that prevents warping of a printed circuit board when the printed circuit board has an extremely thin shape and improves resistance to bending strength.

Further, according to the present invention, it is possible to prevent the warp of the printed circuit board when the printed circuit board has an extremely thin shape and to improve the resistance against bending strength by using a simple and inexpensive structure without using a separate component. It is an object of the present invention to provide a card-type electronic device that can be used.

[0006]

According to the present invention, in a card-type electronic device constituted by using a double-sided printed circuit board, pattern mounting areas on both sides of the board are made substantially equal to each other in a heat treatment process such as reflow. It is characterized in that the conditions of thermal deformation are equalized to prevent the substrate from warping.

Further, according to the present invention, in a card-type electronic device constructed by using a double-sided printed circuit board, a dummy pattern is formed in a dead space of the board, and the pattern mounting areas on both surfaces of the board are substantially matched. It is characterized in that the conditions of thermal deformation are equalized to prevent the warp of the substrate and that the resistance against bending strength is improved.

Further, according to the present invention, in a card type electronic device constructed by using a double-sided printed circuit board, a copper pattern is arranged in a specific circuit component mounting area on at least one surface of the board. In addition, the strength of the specific circuit component mounting portion on the board surface is reinforced.

Further, according to the present invention, in a card type electronic device constructed by using a double-sided printed circuit board, a copper pattern is arranged in a specific circuit component mounting area on at least one surface of the board. By substantially matching the pattern mounting areas on both sides of the board, the strength of the specific circuit component mounting part on the board surface is reinforced, the resistance to bending strength is improved, and the conditions of thermal deformation are equalized. It is characterized by preventing the warp of.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show the present invention in SD (Secure Dig
It shows a first embodiment when applied to an ital card, in which 10 is a card case and 20 is an ultrathin double-sided printed circuit board (hereinafter simply referred to as a board). Card case 1
0 is made of a synthetic resin material having a flat rectangular shape.
On one surface 20A of the substrate 20, as shown in FIGS. 1C and 2, a plurality of contact terminals TP, ...
, The contact terminals TP, ... Are exposed, and one surface 20A of the substrate 20 is flatly coated with a protective film (resist) 30 made of, for example, an ultraviolet curable resin to cover the card surface. Is forming. Further, as shown in FIG. 3, a mounting pattern of circuit components and a predetermined circuit pattern are arranged on the other surface 20B of the substrate 20, and a circuit component (not shown) is solder-mounted by reflow on the mounting pattern of the circuit component. It The other surface 20B of the substrate 20 is entirely covered with the flat card case 10 shown in FIG. 1A as shown in FIG. 1B to protect the internal circuit components.

Here, on one surface 20A of the substrate,
Ground pattern G where most of the board surface is ground potential on the circuit
Covered by P. In the figure, Pa is a circuit pattern serving as a signal path, and TH is a through hole.

Further, on one surface 20A of the substrate,
There are many dead spaces (refer to the DP portion in the figure) except for the portions where the mounting patterns of the circuit components and the circuit patterns Pb, Pb, ... Which serve as signal paths are arranged.

Thus, one surface 20A of the ultrathin substrate
When the mounting area of the pattern on the other surface 20B is significantly different from that on the other surface 20B, the substrate is warped in a heat treatment process such as reflow. In the above example, one surface 20A of the substrate covered by the ground pattern GP extends, and the other surface 20B having a large dead space contracts to cause warpage.

Therefore, in the present invention, the circuit patterns Pa and P serving as signal paths are formed on the other surface 20B of the substrate 20.
As shown in FIG. 3, a dummy pattern D is formed in each of the dead spaces where a new pattern can be formed while avoiding a.
P, DP, ... Are arranged, and further, a part of the circuit pattern serving as a permissible signal path is widened, and the pattern mounting area of the other surface 20B of the substrate 20 is set to one of the substrates shown in FIG. The pattern mounting area of the surface 20A is made substantially equal. Furthermore,
In order to electrically stabilize the circuit, the dummy patterns DP, DP, ... Are provided through holes TH, T, respectively.
The dummy patterns DP, DP, ... Are fixed to the ground (GND) level by circuit connection to the ground pattern GP arranged on one surface 20A of the substrate via H ,.

As described above, the warp of the ultrathin substrate 20 can be kept within a specified range by making the pattern mounting areas of the one surface 20A and the other surface 20B of the substrate 20 substantially the same.

FIG. 4 shows another embodiment of the present invention. Here, one surface 20 of the substrate 20 shown in FIG.
Circuit component mounting areas 21 and 22 on the other surface with respect to A
, Large island-shaped copper foil patterns LP, LP are arranged avoiding the circuit pattern serving as a signal path, and the circuit component mounting area in which integrated circuit components etc. are mounted by the copper foil patterns LP, LP. 21 and 22 are reinforced so that the circuit component mounting area 2 can be prevented from bending and warping due to external stress of the board.
1, 22 and the integrated circuit components and the like mounted therein are protected. Further, by substantially matching the pattern mounting areas on both surfaces of the substrate 20 including the copper foil patterns LP, LP,
The warp of the ultrathin substrate 20 can be kept within a specified range. By fixing the copper foil patterns LP, LP to the ground level via a through hole (not shown), a shielding effect can be expected for a mounted circuit component, or it can be used as a heat conductor for heat dissipation. Alternatively, it can be used as a power supply circuit pattern or the like.

In each of the above embodiments, only one surface of the substrate 20 is covered with the card case and the other surface is covered with the protective film 30.
An example of a card structure that is exposed by coating with the above is shown as an example. In another embodiment, two circuit component mounting areas 21 and 22 are provided.
Although an example in which the copper foil patterns LP, LP are arranged is shown as a target, for example, a structure in which both sides of the substrate are covered with a card case, 3
The present invention can be applied to various card structures and pattern configurations, such as a configuration in which a copper foil pattern is provided in each area targeting circuit component mounting areas at more than one place.

[0019]

As described above in detail, according to the present invention, in a card type electronic device, a printed circuit board having an extremely thin shape with a simple and inexpensive structure without using separate parts is provided. The warp can be prevented, and the resistance to bending strength can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a card-type electronic device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a pattern configuration example of one surface of a substrate in the above embodiment.

FIG. 3 is a diagram showing a pattern configuration example of the other surface of the substrate in the above embodiment.

FIG. 4 is a diagram showing a pattern configuration example of the other surface of the substrate according to another embodiment of the present invention.

[Explanation of symbols]

10 ... Card case 20 ... Board (ultra-thin double-sided printed circuit board) 20A ... One side of substrate 20B ... The other surface of the substrate 20 21, 22 ... Circuit component mounting area 30 ... Protective film DP ... dummy pattern TP ... Contact terminal TH ... through hole GP ... Grand pattern Pa, Pb ... Circuit pattern serving as signal path LP ... Copper foil pattern

Claims (10)

[Claims] 1. A card-type electronic device configured by using a double-sided printed circuit board, characterized in that pattern mounting areas on both surfaces of the substrate are substantially the same. 2. The card type electronic device according to claim 1, wherein the same material is used for the patterns on both surfaces of the substrate. 3. The card type electronic device according to claim 1, wherein at least one surface of the substrate is provided with a dummy pattern so that the pattern mounting areas on both surfaces of the substrate are substantially the same. 4. The card-type electronic device according to claim 1, wherein a dummy pattern is formed in a dead space of the substrate, and pattern mounting areas on both surfaces of the substrate are substantially matched. 5. The card-type electronic device according to claim 3, wherein the dummy pattern is circuit-connected to a ground pattern arranged on opposite surfaces of the substrate. 6. A card-type electronic device configured by using a double-sided printed circuit board, wherein a copper pattern is provided in a specific circuit component mounting area on at least one surface of the board. A small card-type electronic device that does. 7. The small card type electronic device according to claim 6, wherein pattern mounting areas on both surfaces of the substrate are made substantially equal by the copper pattern. 8. The card-type electronic device according to claim 6, wherein the copper pattern is circuit-connected to a ground pattern arranged on opposite surfaces of the substrate. 9. A plurality of external connection terminals and a ground pattern are disposed on one surface of the substrate, and a circuit component mounting pattern and a circuit wiring pattern are disposed on the other surface of the substrate, the substrate excluding the external connection terminals. 7. The card type electronic device according to claim 1, which is covered and protected by an electrically insulating member. 10. In a card-type electronic device configured by using a double-sided printed circuit board, a dummy pattern is arranged in a dead space of a surface of the board where the pattern mounting area is small, and pattern mounting on both surfaces of the board is performed. A method for preventing warpage of a card-type electronic device, which is characterized in that areas are substantially the same.