Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-03-30
2001-03-20
Tolin, Gerald (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S689000
Reexamination Certificate
active
06205027
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application relates to Japanese Patent Application No. 10-88785 which was filed on Apr. 1, 1998, and which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure and method for mounting a circuit module suitable for electronic equipment, and more particularly, to a structure for enhancing a ground connection of a multi-chip module suitable for electronic equipment, especially to a handheld computer with a slim body.
2. Discussion of the Related Art
Many types of electronic equipment are utilizing IC packages for performing at higher operational speeds and have small and light bodies.
Recently, a multi-chip module (MCM) was used as a package for the coming generation of small and light electrical equipment because the MCM can achieve higher operational speeds and efficiencies for electronic equipment, i.e., a hand-held computer when compared to a single chip module (SCM).
The MCM package includes a wiring board for mounting a plurality of IC chips on it. However, the SCM package includes only one IC chip on the wiring board. The SCM is inferior to the MCM for a signal transmission speed between the IC chip and the wiring boards.
Presently, the MCM is usually mounted on a main circuit board by using a plurality of stacking connectors. Each of the stacking connectors is constructed of a pair of male and female connectors for coupling with each other. Either one of the male connector or the female connector is soldered on a wiring board. The other connector of the pair is soldered on the main circuit board. Thus, the grounding of the MCM and the main circuit board is achieved through a grounding terminal on the stacking connector.
Consequently, one needs to increase the number of grounding terminals for the stacking connectors in order to strengthen the grounding connection or a magnetic shield for the MCM. However, it is difficult to increase the number of grounding terminals since one must change the structure of the stacking connectors.
Further, presently, there are slight variations among the heights of the IC chips in the MCM since the respective IC chips are mounted on the circuit board by coupling the pair of male and female connectors. Thus, the connectors happen to vary slightly in their coupling strengths during the connecting process for the stacking connectors.
The variation among the stacking connectors causes a problem for small-sized electrical equipment, particularly for equipment with a slim body, such as a hand-held computer.
One need for the hand-held computer with the slim body is to install a heat sink for cooling the CPU module made for the MCM. For achieving a sufficient cooling effect, it is important to maintain a particular clearance between the MCM and the heat sink. Since the hand-held computer with the slim body does not have sufficient space for providing many chip devices, the variation among the stacking connectors influences the clearance between the MCM and the heat sink.
If the clearance between the MCM and the heat sink is too much larger than a particular value, a thermal conduction from the MCM is prevented. On the contrary, if the clearance is too much smaller than a particular value, the MCM is pressed against the heat sink. This closeness has bad effects for the operation of the MCM.
SUMMARY OF THE INVENTION
Accordingly, it is object of the present invention to solve the aforementioned problems and defects of the conventional circuit module structure including a plurality of IC chips on a base circuit board.
Another object of the present invention is to provide a novel structure and method for mounting the circuit module on the base circuit board with strengthening of the grounding connection for the plurality of IC chips in the circuit module without changing the connecting structures for the plurality of IC chips.
A further object of the present invention is to provide a novel structure and method for mounting a circuit module on a base circuit board while keeping a precise distance between them.
A still further object of the present invention is to provide a novel structure and method for mounting a CPU module on a base circuit board in a hand-held computer for strengthening the ground connection or the magnetic shield of a plurality of IC chips in the CPU module without changing the connecting structures for the plurality of IC chips.
A still further object of the present invention is to provide a novel structure and method for mounting the CPU module on a base circuit board for a compact hand-held computer while keeping a precise distance between them.
A still further object of the present invention is to provide a novel structure and method for mounting a CPU module on a base circuit board in a hand-held computer by a simple fixing means.
For achieving these objects, a circuit module mounting structure according to the present invention comprises a circuit module including a wiring board provided with a printed grounding pattern, a plurality of IC chips mounted on the wiring board, and a housing case for containing the wiring board. The plurality of IC chips is connected to the printed grounding pattern, the wiring board has a plurality of first holes through the printed grounding pattern, and the housing case has a plurality of second through holes which correspond to the first through holes.
A base circuit board for mounting the circuit module in a predetermined mounting area on the base circuit board has a plurality of third through holes which correspond to the first through holes of the wiring board. Each of the plurality of third through holes is surrounded by a land portion provided on the base circuit board for securing a connection to the printed grounding pattern within the predetermined mounting area.
A means for supporting the circuit module at the predetermined mounting area on the base circuit board includes a plurality of attached bosses for coupling together the plurality of first through holes of the wiring board and the plurality of second through holes of the housing case, respectively.
Also, there are means for firmly fixing the connection among the plurality of attached bosses and the plurality of first through holes in the wiring board and also for fixing the connection among the plurality of attached bosses and the plurality of second through holes in the base circuit.
Further, the hand-held computer having a CPU module mounting structure according to the present invention is characterized in that it is comprised of the CPU module including a wiring board provided with a printed grounding pattern, a plurality of IC chips mounted on the wiring board, and a housing case for containing the wiring board. The plurality of IC chips is connected to the printed grounding pattern, the wiring board has a plurality of first holes through the printed grounding pattern, and the housing case has a plurality of second through holes which correspond to the first through holes.
A base circuit board for mounting the CPU module in a predetermined mounting area on the base circuit board has a plurality of third through holes which correspond to the first through holes in the wiring board. Each of the plurality of third through holes is surrounded by a land portion provided on the base circuit board for securing a connection to the printed grounding pattern within the predetermined mounting area.
A means for supporting the CPU module at the predetermined mounting area on the base circuit board includes a plurality of attached bosses for coupling together the plurality of first through holes of the wiring board and the plurality of second through holes of the housing case, respectively.
Additionally, there are means for commonly fixing the plurality of attached bosses which correspond to the plurality of first through holes in the wiring board and also for fixing the plurality of attached bosses which correspond to the plurality of second through holes in the housing case.
Further, the method for mounting a ci
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tolin Gerald
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