JPH03173696A - Electronic apparatus - Google Patents

Abstract

PURPOSE:To integrate a housing and an electric circuit board and to omit a board exclusive to printed wiring by using a pare-type aramid film or its laminate. CONSTITUTION:A card-shaped housing substrate having an opened recessed part 2 for mounting electronic components 3 composed of a pare-type aramid film is formed by a hot pressing molding method using a material. Electric wiring 4 is provided on this substrate and electric components 3 such as an IC chip, a capacitor, a connector or the like are soldered thereto and a surface plate 5 or 5' is mounted to the single surface or both surfaces thereof by adhesion. Since the pare-type aramid film having both of heat resistance and hot pressing moldability is used as a substrate material in this process, an IC card having perfect soldering heat resistance and showing high reliability and high accuracy can be formed and, since hot pressing molding can be performed in a relatively easy manner and a printed circuit board can be omitted, a product can be miniaturized and reduced in its wt.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a portable electronic device such as a so-called RC card, which is equipped with an electronic device such as a central processing unit (CPU) and a data memory.

[Conventional technology]

Conventionally used IC cards differ in internal structure, device arrangement, connector shape, etc. depending on the manufacturer, but the main body of the overall structure is the housing, which has a CPU, data memory,
After separately fitting printed wiring boards with electronic components such as connectors and batteries, aluminum or plastic surface plates are attached to both sides of the card-like base (=J
It is structured according to the following.

That is, in such a configuration, a so-called printed wiring board, in which a circuit is printed on a board separate from the housing, is commonly used. However, such printed circuit boards are generally created by creating a flat board specifically for a specific printed circuit from thermosetting resin such as phenol resin or epoxy resin, coating it with copper, and then applying resist, etching, plating, etc. be done. Then, transistors, resistive elements, capacitors, and other electrical and electronic components are soldered to the printed circuit board carrying the desired circuit, thereby completing the circuit portion of the electrical product. This circuit section is then assembled with other components into the housing of the product and performs its intended function.

[Problem to be solved by the invention]

However, when assembling electronic and electrical products using such conventional printed circuit boards, there are the following problems. First, since the circuit is fixedly arranged on a dedicated flat plate, it is necessary to secure at least enough space within the product to accommodate the flat plate for the circuit, making it difficult to miniaturize the product. This problem must be given particular importance, especially now that the size of electrical products is becoming smaller. In order to arrange the circuit within a limited space, it is possible to divide the printed circuit board into several parts, but in that case, extra effort is required to create the printed circuit board. However, additional problems arise, such as the need to consider wiring between printed circuit boards.

Next, since the printed circuit board has a planar structure, there is little freedom in the design of the resulting product. It is particularly difficult to solve this freedom of design along with the above-mentioned space problem. Furthermore, printed circuit boards are manufactured through complicated processes and are expensive. In addition, the shape of the housing portion, which is supposed to provide strength, is constrained, and it requires some effort to maintain overall strength within a limited volume, and it also requires a lot of effort to fit the housing.

As a method to solve these problems,
Japanese Patent No. 22599 discloses a portable electronic device that uses a liquid crystalline polyester resin as a card-like housing base, has electrical wiring formed directly on the surface of the base, and mounts electronic components. However, although the liquid crystalline polyester resin disclosed in this publication has a certain degree of soldering heat resistance, it has the disadvantage that only low melting point solder can be used or that the soldering conditions are limited to special ones.

That is, when standard solder is used, it often becomes deformed or misaligned, resulting in a lack of reliability.

[Means to solve the problem]

The purpose of the present invention is to solve these problems by applying thermoforming to a para-aramid film, which was thought to be impossible in the past, and using this as a card-like housing base. The idea was to form electrical wiring directly on the surface of the substrate and mount electronic components on it.We also developed not only a para-aramid film alone, but also a layer of heat-resistant resin or fiber-reinforced resin as the substrate. We have arrived at the present invention by confirming that these substrates can be used and that these substrates have perfect solder heat resistance.

That is, the first aspect of the present invention is characterized in that the main parts include a card-like housing base made of a para-aramid film, electrical wiring formed directly on the surface of the base, and an electronic device connected to the electrical wiring. A portable electronic device, and the second aspect of the present invention is a para-aramid film and a thermosetting resin or 270°C
The main parts include a card-shaped housing base made of a laminate with a thermoplastic resin that does not melt or flow under less than 10 minutes, electrical wiring formed directly on the surface of the base, and an electronic device connected to the electrical wiring. A third aspect of the present invention is a portable electronic device, and a third aspect of the present invention is a thermosetting resin reinforced with a para-aramid film or two.
A card-shaped housing base formed by laminating a thermoplastic resin layer that does not melt or flow at temperatures below 70°C and a thermosetting resin reinforced with carbon fiber or a thermoplastic resin layer that does not melt or flow at temperatures below 270°C, and the surface of the base. This is a portable electronic device characterized in that its main parts include electrical wiring directly formed on the electrical wiring and an electronic device connected to the electrical wiring.

- Here, the card-shaped housing base is a product that integrates the printed wiring board and housing portion of a conventional IC card, and has open recesses for mounting electronic components such as IC chips, capacitors, and connectors. It is a card-shaped integral molding.

After electronic components are mounted on this card-like base, a surface plate is attached if necessary to complete a portable electronic device.

In order to manufacture the portable electronic device of the present invention, first, as shown in FIG. Manufactured using hot pressure molding method.

As means for providing electrical wiring on the card-shaped housing base 1, various conventionally known methods can be used. Of course, both the subtract method and the additive method can be used.

For example, a method can be used in which a copper plate is adhered to the part of the molded product where electrical wiring is required, before or after hot-press molding, and the copper plate is etched using a conventional method to leave the wiring part. Alternatively, it is also possible to use a method in which metal is laminated by vapor deposition, sputtering, ion-blating, etc. in areas where electrical wiring is required, copper is then laminated by plating, and then etched to leave the wiring.

The card-shaped housing base having the circuit obtained in this way is then soldered with electronic components such as IC chips, capacitors, and connectors, and a surface plate 5 or 5' is attached to one or both sides of the base by adhesive or other methods to create a product. Completed as.

The para-aramid film used in the present invention is a film made of a polymer in which the para-position of aromatic rings or a position similar thereto is directly connected with an amide bond. That is, +
NH-8r+ to NHCO-Arz-GO-+- or -←
It has a general structure of NH-Ar3-CO→-, Ar, ~Δ
As r3, paraphenylene, 1,4-naphthalene,
■, 5-naphthalene, 2.6-naphthalene, 4.4'-
Biphenylene, 4.4'-biphenylene ether, 3
．． 4'-biphenylene ether and these alkyls,
Substituents such as halogen, nitro, methoxy, and ethoxy are selected. It may be a copolymer or a homopolymer. Most typically, polyparaphenylene terephthalamide or polyparabenzamide is used. Various methods have been disclosed for obtaining films from these para-aramids, and any of these methods can be used.

For example, the above-mentioned para-aramid is dissolved in an amide solvent such as N-methylpyrrolidone or dimethylacetamide, a mixed solvent of lithium chloride or calcium chloride, or an inorganic acid solvent such as sulfuric acid. It can be formed into a film using methods such as

Para-aramid film usually has a thickness of 10 to 200μ
A thickness of m is suitable. In addition, the para-aramid film has a strength of 35 kg/mm2 or more, and a strength of 600 kg
It is preferable to use a material having an elastic modulus of 1/in" or more.

In the present invention, the para-aramid film itself may be used alone as a card-shaped housing substrate, but it can also be used as a card-shaped housing substrate by forming a laminate of the film and a thermosetting resin or a highly heat-resistant thermoplastic resin. It can also be used for. In the latter case, the rigidity of the housing base can be improved, and if necessary, it is also possible to further laminate the laminate. Thermosetting resins include epoxy resins, polyester resins, polyimide resins,
Phenol resin etc. can be used, and as a highly heat resistant thermoplastic resin, 2
A material that does not melt or fluidize at temperatures below 70°C is selected, such as polyphenylene sulfide, polyetherketone, polyetherimide, etc. In order to improve the adhesion between these resins and the para-aramid film, it is preferable that the film surface be subjected to surface treatment such as roughening, plasma treatment, corona discharge treatment, etc.

The third aspect of the present invention is to laminate a laminate of a para-aramid film and a thermosetting resin or a highly heat-resistant thermoplastic resin onto a carbon fiber-reinforced thermosetting resin or a highly heat-resistant thermoplastic resin layer. Then, it is used as a corner-shaped housing base.

0 This greatly improves the rigidity of the housing base and also provides electromagnetic shielding effects.
Of course, it maintains hot press moldability.

In the present invention, inorganic short fibers or powder particles, such as glass fibers, carbon fibers, or metal fibers, are added inside the para-aramid film or inside the thermosetting resin or highly heat-resistant thermoplastic resin. , ceramic fibers, boron fibers, potassium titanate fibers, general inorganic fibers such as asbestos, calcium carbonate, highly dispersed silicates, alumina, aluminum hydroxide, talc, clay, mica, glass flakes, glass beads, glass peas, Powder substances such as quartz powder, silica sand, wollastonite, various metal powders, carbon black, barium sulfate, calcined gypsum, etc., and powder-like or plate-like inorganic compounds such as silicon carbide, alumina, poron nitride, silicon nitride, etc. , whiskers, metal whiskers, etc. can be dispersed therein, and can be used to increase the rigidity of the card-shaped housing base. In addition, stabilizers such as plasticizers, antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, and colorants such as dyes and pigments can also be contained.

〔Example〕

Example 1 A 40 pm transparent film made of polyparaphenylene terephthalamide was produced by applying the method disclosed in Japanese Patent Publication No. 57-1'N386.

This film was a highly rigid isotropic film having a density of 1.38 g/c+fl, a strength of 41 kg/mm2, and an elongation of 53%. After adhering a 35 μm copper plate to this film with epoxy resin, resist painting, exposure,
The wiring portion was left using conventional methods such as etching.

Next, predetermined positions on this board were hot-pressed using a tool heated to about 400"C to create 10 recesses of approximately 5 to 20 mm2. Electronic components such as IC chips and capacitors were placed in the predetermined positions of the recesses and soldered. An IC card as shown in Figure 1 was made by attaching a decorative aluminum plate to both sides with adhesive.

Example 2 Approximately 10μ of epoxy resin was added to the film used in Example 1.
It was coated to a thickness of m to bring it into a so-called B stage state. Next, make a recess of a predetermined size in a predetermined position of this.
It was formed by hot pressing with a tool heated to 0'C and the whole was cured.

Next, a copper plate was laminated with epoxy resin on the side having the concave portion, and wiring was formed by a series of steps such as resist painting, exposure, and etching. A card-shaped substrate having greater rigidity than that of Example 1 was produced.

Furthermore, an IC card was produced by the same operation as in Example 1.

Example 3 In this example, a prepreg made of carbon fiber and an epoxy resin was used as the film prepreg 2 used in Example 2.
A card-like substrate material was obtained by stacking these sheets in a sandwich-like manner from above and below.

That is, the above laminate was subjected to hot pressure molding to form recesses at predetermined positions, and then an IC card was produced in exactly the same manner as in Example 2. This card had even greater rigidity than Example 2.

〔Effect of the invention〕

In the present invention, a para-aramid film having both heat resistance and thermoformability is used as the card-like substrate material.
It has complete solder heat resistance, and even when soldering is performed, the board will not warp or the wiring will be distorted.
Hot pressure molding can be done relatively easily at 00°C. In other words, by using para-aramid film or its laminate, it is possible to directly attach an electric circuit to the housing of a portable (card-like) electronic device and integrate the housing and the electric circuit board, making it possible to integrate the housing and the electric circuit board. Since the substrate can be omitted, all conventional problems caused by its use can be eliminated. That is, not only can the time, labor, and expense required for producing a printed circuit board be eliminated, but also the space occupied by the printed circuit board can be eliminated from within the product. This means that the product can be made smaller and lighter, which also reduces costs. Further, the 3 4 circuit can be configured three-dimensionally, and the degree of freedom in designing the housing can be increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional assembly view of one example of the IC card of the present invention. ■ -Card-shaped housing base 2 ・-Electronic component mounting recess 3 ・-Electronic component 4 ・-Electrical wiring 5- Surface plate 6 ・-Surface plate mounting frame

Claims (1)

[Claims] 1. A mobile phone characterized in that the main parts include a card-like housing base made of para-aramid film, electrical wiring formed directly on the surface of the base, and an electronic device connected to the electrical wiring. Possible electronic devices. 2. Para-aramid film and thermosetting resin or 270
The main parts include a card-like housing base made of a laminate with a thermoplastic resin that does not melt or flow at temperatures below ℃, electrical wiring formed directly on the surface of the base, and an electronic device connected to the electrical wiring. portable electronic device. 3. A thermosetting resin layer reinforced with para-aramid film or a thermoplastic resin layer that does not melt or flow at temperatures below 270°C, and a thermosetting resin layer reinforced with carbon fiber or a thermoplastic resin layer that does not melt or flow at temperatures below 270°C. What is claimed is: 1. A portable electronic device characterized in that its main parts include a card-like housing base formed by laminating a card-like housing base, electrical wiring formed directly on the surface of the base, and an electronic device connected to the electrical wiring.