Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-09-18
2002-04-30
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S730000, C361S728000, C361S736000, C235S492000, C439S945000, C439S946000
Reexamination Certificate
active
06381143
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-359462, filed Dec. 17, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a card-type electronic apparatus such as a portable-type multi-media card having a built-in flash memory, and also to a method of manufacturing such a card-type electronic apparatus.
In recent years, portable-type multi-media cards having a build-in flash memory have come to be widely used. The multi-media cards of this type, which have a small-size and are easily used with high quality, are expected to be applied to portable-type information apparatuses such as portable telephones and multi-media apparatuses such as music players and digital cameras, as external storage media for storing video images requiring a large capacity, voice and other data.
The conventional multi-media card is constituted by a card case made of a synthetic resin and a memory module. The card case is standardized to have length and width dimensions corresponding to a small post-stamp size, and also to have a thickness of approximately 2 mm. This card case is constituted by a first case having a bottom wall and a second case having a top wall. The first case and the second case are joined to each other by aligning the outer circumferential edge of the bottom wall and the outer circumferential edge of the top wall face to face and fitting them to each other.
The memory module is housed inside the card case. The memory module has a circuit substrate and a plurality of electronic parts mounted on this circuit substrate. The circuit substrate is placed inside the card case in parallel with the bottom wall of the first case and the top wall of the second case. A plurality of power-apply terminals having a rectangular shape are placed on the front end of the circuit substrate. The power-apply terminals are aligned in a row in the width direction of the card case, and exposed to the outside of the card case through an opening formed in the bottom wall.
The electronic parts include a semiconductor package constituting a large capacity flash memory, an LSI chip and capacitors constituting a controller, etc., and these electronic parts are electrically connected to the power-apply terminals. For this reason, in the conventional multi-media card, the circuit substrate and the electronic parts are housed inside the card case in a stacked manner in the thickness direction of the card case.
The circuit substrate of the memory module has a first surface opposing the bottom wall of the first case and a second surface opposing the top wall of the second case. Here, in the conventional memory module, there are two cases in which the electronic parts are mounted on both of the first and second surfaces in a separate manner and in which all the electronic parts are mounted on either the first surface or the second surface of the circuit substrate as one lot.
In the case of the memory module with a circuit substrate having the electronic parts mounted on the first and second surfaces thereof, it is necessary to maintain inside the card case a space having a height dimension set by adding at least the thickness of the circuit substrate, the height of the electronic parts on the first surface and the height of the electronic parts on the second surface. Consequently, the thickness dimension of the card case is increased, causing a problem with the thinness of multi-media cards.
In the case of the memory module with a circuit substrate having the electronic parts mounted on only one side thereof, the circuit substrate can be placed along the bottom wall or the top wall of the card case. For this reason, it is possible to make the card case thinner.
In this structure, however, most of one surface of the circuit substrate is occupied by the mounting space of the electronic parts. Consequently, the power-apply terminals need to be placed on the surface of the circuit substrate opposite to the electronic parts. Here, since the power-apply terminals need to be exposed to the outside of the card case through the opening in the bottom wall, the circuit substrate needs to be placed along the bottom wall. This causes an extreme reduction in the dimension from the opening end of the opening to the power-apply terminals.
In other words, since the thickness of a multi-media card is as thin as approximately 2 mm, the thickness of the bottom wall of the card case needs to be as thin as approximately 0.3 mm. For this reason, it is not possible to provide a sufficient step between the outer surface of the bottom wall and the power-apply terminals. Consequently, for example, when a multi-media card is pinched by the hand, the finger tip tends to touch the power-apply terminals, with the result that the electronic parts might be seriously damaged by static electricity possessed by the human body. Moreover, a finger print or oil components from the finger tip might adhere to the power-apply terminals, resulting in disconnection.
Furthermore, in the conventional multi-media card, the card case is assembled by applying vibrational energy derived from ultrasonic waves to the butt portions of the first case and the second case and joining the two cases to each other. More specifically, the outer circumferential edge of the first case and the outer circumferential edge of the second case are aligned to butt against each other, and the outer circumferential edges of these cases are then pinched by a ultrasonic wave head and a fixed table; thus, in this state, the ultrasonic wave vibration is applied to the outer circumferential edges of the first and second cases. Consequently, the outer circumferential edges of the first and second cases are thermally melted and joined to each other all around the edges to form a card case.
In the conventional card case, the thickness dimension of the outer circumferential edges of the first and second cases is set to be constant all around the edges. For this reason, when the outer circumferential edge of the first case and the outer circumferential edge of the second case are aligned to butt against each other, the thickness of these butt portions becomes greater, thereby making the gap between the ultrasonic wave head and the fixed table greater. As a result, when the butt portions of the outer circumferential edge of the first case and the outer circumferential edge of the second case are subjected to ultrasonic wave vibration and allowed to melt, the capacity of the butt portions that are thermally affected becomes too great. Therefore, upon completion of the melt-joining of the first case and the second case, a thermal strain tends to occur in the outer circumferential portion of the card case, and the residual stress due to the thermal strain becomes greater.
Consequently, the card case might be deformed in a warping manner after the melt-joining process, and the flatness of the bottom wall and the top wall of the card case might be impaired. In addition, the above-mentioned residual stress tends to cause the outer circumferential portion of the card case to deform outwards in a swelling manner, resulting in degradation in the dimensional precision in the card case.
Moreover, in the conventional multi-media cards, the circuit substrate of a memory module is firmly fitted to the inside of the first case. Here, the outer circumferential edge of the first case is thicker and has a greater capacity in receiving the ultrasonic vibration; therefore, the ultrasonic vibration applied to the outer circumferential edge is not readily absorbed by the fixed table. For this reason, the ultrasonic vibration, applied to the outer circumferential edge of the first case, as it is, is allowed to reach the electronic parts through the circuit substrate, with the result that the precise electronic parts might be seriously damages by the ultrasonic vibration, or might be broken.
BRIEF SUMMARY OF THE INVENTION
It is a firs
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Gaffin Jeffrey
Kabushiki Kaisha Toshiba
Phan Thanh S.
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