JPH02198896A - Portable electronic machinery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to portable RF and electronic devices such as IC cards.

(Prior Art) In recent years, IC cards, for example, have been attracting attention as portable electronic devices with built-in electronic components such as a CPU and memory. Prevention of destruction has become an important issue.

FIG. 3 shows an example of an IC7J-board, and as is clear from the cross-sectional mechanical diagram, both sides of the board 4, on which the electronic component 1 is wire-mounted in the storage hole 2 and sealed with the resin 3, are shown. It has a structure in which it is fixed between an outer plate 6 made of resin or the like and a spacer 7 via a fixing medium layer 5 made of adhesive or pressure-sensitive adhesive. In addition, in Figure 3,
8 is a printing film that is adhered to a spacer and has various information printed on it. In such a configuration, when the IC card receives a bending moment as shown by the arrow △, the board 4
Since the electronic component 1 is mounted biased toward the bottom surface 4b of the board with respect to the center of the thickness of the root 4, and the outer plate 6 is thicker than the spacer 7 and has higher rigidity, the bending neutral plane H1 is relatively Dl from the bottom surface 1a of the electronic component near the top surface 4a of the board
It will be located a distance away. Here, the stress applied to the bottom surface 1a of the electronic component 1 due to the bending moment A is proportional to the distance from the bottom surface 1a of the electronic component to the bending neutral plane.

Therefore, if the bending neutral plane H1 of the board 4 is located close to the top surface 4a of the board as described above, the stress on the electronic component 1 will increase, so the position of the bending neutral plane of the board 4 will be There is a strong need for a method to bring the electronic component closer to the bottom surface 1a.

(Problems to be Solved by the Invention) As described above, a method for moving the bending neutral plane of the substrate 4 in a direction that makes it difficult to apply stress to the electronic component 1 has been desired.

The present invention has been made in view of the above, and an object thereof is to provide a portable electronic device that can contribute to improved strength against deformation.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a portable electronic device in which both sides of a board on which electronic components are mounted are sandwiched and fixed between plate materials via a fixing medium. The gist of the invention is that the shear modulus of the adhesion medium layers formed on both sides of the substrate are different from each other.

(Function) In the portable electronic device according to the present invention, the shear elastic modulus of the adhesive medium layers formed on both sides of the substrate on which electronic components are mounted are made different from each other, so that the bending neutral plane of the substrate is adjusted. This allows it to be set in a position where stress is less likely to be applied to the mounted electronic components.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows an embodiment in which a portable electronic device according to the present invention is applied to an IC card. Its features include a fixing medium layer 11 for fixing the outer plate 6 and the spacer 7 to the top surface 4a of the substrate and the bottom surface 4b of the substrate, respectively.
．． By making the shear elastic modulus of 13 different, the bending neutral plane H2 of the substrate 4 is positioned closer to the bottom surface 1a of the electronic component and 02 (<Dl) away from the bottom surface 1a of the electronic component compared to the conventional case. As a result, as described above, the shorter the distance from the bottom surface 1a of the electronic component to the mid-bending plane of the board 4, the smaller the stress applied to the bottom surface 1a of the electronic component. This makes it difficult for stress to be applied to the structure, contributing to the prevention of breakage. In addition, the first
In the figure, the same parts as in FIG. 3 are given the same reference numerals, and detailed explanations are omitted.

As a method of making the shear elastic modulus of the fixed medium 11111.13 different, for example, a method of using adhesives or pressure-sensitive adhesives that constitute the fixed medium WJ11.13 having different physical properties, or a method of using at least one of them as shown in FIG. One of the fixing medium layers has a structure in which a fixing medium 15 as an adhesive or adhesive is partially applied, in other words, the coating area of the fixing medium 15 degrees Vf! Possible methods include making m different, making the thickness of the fixing medium layer different, and so on. Specifically, in the configuration shown in FIG. 1, in order to reduce the stress on the electronic component 1 due to the bending moment A, it is necessary to
The shear modulus of elasticity of one adhesive medium layer 13 may be lower than that of the other adhesive medium layers 13. Therefore, in the method shown in FIG. 2 described above, only the fixing medium layer 11 needs to be partially coated with the fixing medium 15, and in the method of varying the thickness, the fixing medium layer 11 is coated with other fixing media. It is only necessary to make it thicker than the medium layer 13.

The position of the bending neutral plane H2 of the substrate 4 changes depending on the degree of difference in shear modulus of the fixed medium layers 11 and 13, but the most desirable position is the center of the thickness of the electronic component 1.

[Effects of the Invention] As explained above, according to the present invention, the shear elastic modulus of the adhesion medium layers formed on both sides of the board on which electronic components are mounted is made different from each other, so that the bending neutral plane of the board can be adjusted. Since it can be set at a position where stress is less likely to be applied to the mounted electronic components, it is possible to improve the strength against deformation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram for explaining the configuration of FIG. 1, and FIG. 3 is a diagram showing a conventional example. 1... Electronic component 2... Storage hole 3... Resin 4... Substrate 5... Fixing medium layer 6... Outer plate 7... Spacer 8... Printing film 3... Fixed medium layer 5...Fixed medium A...Bending moment "1 ("2...Bending neutral plane

Claims (1)

[Claims] In a portable electronic device formed by sandwiching and fixing both sides of a board on which electronic components are mounted between plate materials via a fixing medium,
A portable electronic device characterized in that the layers of the fixing medium formed on both sides of the substrate have different shear modulus of elasticity.