Registers – Records – Laminated
Reexamination Certificate
1999-01-05
2002-07-02
Frech, Karl D. (Department: 2876)
Registers
Records
Laminated
C235S492000
Reexamination Certificate
active
06412701
ABSTRACT:
The present invention relates to a flexible IC module which is a basis for information carriers such as contactless IC cards, a method for producing the flexible IC module, and a method for producing information carriers using the flexible IC module.
BACKGROUND ART
Use of contactless information carriers such as contactless IC cards as substitutes for commutation tickets, driver's licenses, telephone cards and cash cards has been investigated, and since extensive use thereof has been expected, one of the most important technical tasks is how to simplify the production steps and reduce the unit cost.
Hitherto, as a method for producing contactless IC cards, there has been known a method which comprises boring holes through a reinforcing material made of glass fiber or the like, storing an IC chip and a coil which is a contactless signal transmission means in the hole, then sealing the hole with a resin to form a substrate, and finally applying cover sheets to the front and back sides of the substrate to obtain the desired contactless IC cards.
According to this method, contactless IC cards in which the position of the coil set in the substrate is accurately regulated can be produced by adjusting the size of the bored hole to a suitable size depending on the size of the coil. Thus, transfer of power and signal between the IC card and the external devices can be performed highly efficiently.
As another method, as disclosed in, for example, NIKKEI MECHANICAL 1997. 1.6, No.497, pp.16-17, a method is proposed which comprises disposing a first resin sheet to which an IC chip and a coil as a contactless data transmission means are bonded and a second resin sheet having no such IC chip and coil at facing portions of a stationary mold and a movable mold of an injection molding machine, respectively, putting the molds together, and then filling a cavity with a resin whereby a contactless IC card comprising the first and second resin sheets, the IC chip and the coil which are integrated with the filling resin is obtained.
According to this method, since a contactless IC card having resin sheets (cover sheets) bonded to the front and back sides can be obtained by injection molding, the contactless IC card can be more efficiently produced and the production cost can be reduced as compared with the conventional method according to which a substrate in which IC chip and coil are embedded is cured and thereafter cover sheets are bonded to the front and back sides of the substrate.
On the other hand, as for the connection of IC chip and coil mounted on the contactless IC card, generally is employed a method of mounting the IC chip on a wiring substrate and connecting the coil to an electrode terminal formed on the wiring substrate.
This method has been technically established and hence the IC chip and the wiring substrate, and the wiring substrate and the coil can be connected with a high reliability.
However, in the former method of the above-mentioned conventional methods for the production of contactless IC cards, IC chip and coil are stored in a hole bored in a reinforcing material, and then inside and outside of the hole are cured with resin. Therefore, the inside of the hole having no reinforcing material is low in strength, and stress is concentrated at the inside of the hole and the substrate is apt to be broken when an improper external force such as bending is applied.
Furthermore, since sealing of the hole with resin and impregnation of the reinforcing material with resin and curing of the reinforcing material must be carried out after the IC chip and the coil are accurately set in the reinforcing material in which the desired hole is bored, the production steps are complicated and cheap information carriers can hardly be produced. Especially, when various contactless IC cards are produced on the same line, various reinforcing materials differing in the size of the holes depending on the size of the IC chip and the coil stored therein. Thus, the production steps are further complicated, resulting in increase of the production cost of contactless IC cards.
On the other hand, since the latter method of the above-mentioned conventional methods for the production of contactless IC cards carries out injection molding with a cover sheet having an IC chip and a coil which are bonded thereto being disposed on one of the molds, a molten resin of high temperature contacts with the portions of the cover sheet to which an adhesive is applied and not applied. Therefore, it has been found that owing to the difference in coefficient of thermal expansion of the portions to which the adhesive is applied and not applied, wrinkles are apt to be formed at the boundary of these portions. According to experiments, it was difficult to produce contactless IC cards having no wrinkles on the cover sheets even when resin temperature, injection speed and injection pressure were variously changed.
Since contactless IC cards are handled by fingers and directly viewed, those having wrinkles on the surface are not good in hand and appearance and lose commercial value. Furthermore, in case the surface of the cover sheet is printed after the production of contactless IC cards, it is impossible to perform beautiful printing on the surface of the cards and they also have no commercial value.
Moreover, the conventional connection method of IC chip and coil requires a wiring substrate as an essential constitutive element. Therefore, it needs a high cost, and it is difficult to make thinner and flexible the contact less IC cards.
The present invention has solved these problems, and the objects of the present invention are to provide a construction of a flexible IC module which makes easy to produce information carriers, to provide a method for producing the flexible IC module at low cost and at high efficiency, and to provide a method for producing an information carrier superior in feeling at use and excellent in appearance at low cost and at high efficiency using the above flexible IC module.
DISCLOSURE OF INVENTION
<Construction of Flexible IC Module>
In order to solve the above problems, as for the construction of the flexible IC module, the present invention employs such construction as comprising a flexible substrate of a given shape and a given size having compressibility in the thickness direction, self-pressure bonding property and resin impregnation property and parts mounted and carried on the flexible substrate, the parts to be mounted being embedded in dents formed by compression in a portion of the flexible substrate.
The parts to be mounted can be completely embedded in the flexible substrate or can be embedded in one side of the flexible substrate ehilr being partly exposed outside. In the former case, the front and back sides of the flexible substrate are formed in a planar state, and in the latter case, the front and back sides of the flexible substrate including the surface of the embedded parts embedded are formed in a planar state.
In the present specification, a “self-pressure bonding property” means such characteristics of the flexible substrate that when a compressive force is applied to the flexible substrate at room temperature or under heating, the fibers constituting the flexible substrate are bonded or when a compressive force is applied to a plurality of stacked flexible substrates, these flexible substrates are bonded to each other, and the flexible substrate(s) are kept at the state of the volume being reduced than before application of the compressive force.
As woven fabrics, knitted fabrics or nonwoven fabrics which per se have the self-pressure bonding property, there may be used those which comprise so-called conjugate fibers each of which is composed of two or more parts differing in melting point; those which are obtained by mixed spinning two or more synthetic resins differing in melting point or which are mixtures of synthetic resin fibers differing in melting point; and those which comprise glass fibers, carbon fibers, Kepler fibers, chemical fibers, natural fibers or c
Daido Kazuhiko
Fukao Ryuzo
Hirai Yusuke
Kohama Kyouichi
Sueyoshi Toshinobu
Cyr Daniel St.
Frech Karl D.
Hitachi Maxell Ltd.
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