Shock-absorbing device for notebook computer module

Details Shock-absorbing device for notebook computer module Shock-absorbing device for notebook computer module

1999-08-18

2001-06-26

Picard, Leo P. (Department: 2835)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S689000, C361S689000, C361S719000, C248S624000, C248S625000

Reexamination Certificate

active

06252768

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a shock-absorbing device. More particularly, the present invention relates to a shock-absorbing device for protecting a notebook computer module.
2. Description of Related Art
As the level of semiconductor integration continues to increase, size of various electronic devices inside a silicon chip becomes smaller. Therefore, the electronic devices need to be carefully protected from damage. In general, a component having a large number of devices is more vulnerable to physical damage than a component having few devices inside. Therefore, a compact component demands more protection.
Using the central processing unit (CPU) of a notebook computer as an example, the limited volume inside a notebook computer demands a CPU that is slightly different from a CPU installed inside a desktop computer. In addition, due to limited air space inside the notebook computer, airflow inside the notebook computer is also restricted. Therefore, heat dissipation is a problem for the CPU inside a notebook computer as well.
FIG. 1
is a schematic, cross-sectional view of a conventional shock-absorbing device around a notebook computer module. As shown in
FIG. 1
, a silicon chip
10
is mounted onto a printed circuit board (PCB)
12
via a connector (not shown). Alternatively, the silicon chip
10
is mounted directly onto the PCB
12
. In. general, a silicon chip installed inside a notebook computer has limited tolerance for temperature, pressure and bending. Because of the poor heat dissipating capability of the chip
10
alone and the vulnerability of the notebook computer to impact while being carried, a protective device is formed behind the printed circuit board
12
and above the chip
10
.
Corresponding in position to chip
10
, there is a backing plate
14
attached to the other side of the printed circuit board
12
. Because the silicon chip
10
usually has a large number of pins that need to be connected to the printed circuit board
12
, the printed circuit board
12
must have a certain degree of planarity to achieve connection. Since most printed circuit boards are not stiff enough, the supporting plate
14
serves as a stiff backing. In addition, the supporting plate
14
also provides some protection against bending to the PCB
12
, because any bending is likely to damage the chip
10
.
Due to the high level of integration on the silicon chip
10
, the amount of heat generated during operation is enormous. Hence, there is a cooling/protective plate
16
on top of the silicon chip
10
. The cooling/protective plate
16
is placed over the silicon chip
10
and fixed onto the printed circuit board
12
by a set of screws
18
. A protruding element
19
above the chip
10
presses against a surface of the cooling/protective plate
16
so that heat generated by the chip
10
can be conducted away quickly. The cooling/protective plate
16
further has an elastic portion
15
that permits the absorption of shock from external impact. However, how to make the cooling/protective plate
16
contact the chip
10
so that heat can be dissipated without exerting too much pressure on the chip
10
itself is a major design consideration. In general, the cooling/protective plate
16
can only absorb forces in one direction. For example, the cooling/protective plate
16
can absorb a force coming from the top of the chip
10
, but cannot withstand a force from the opposite direction. Therefore, the screws must be tightened very carefully so that the cooling/protective plate can exert a correct amount of pressure on the chip
10
. The maximum pressure a silicon chip such as a micro-pin grid array (&mgr;PGA) can tolerate is only about 689 kpa. Due to unevenness of the chip's surface, stress on the silicon chip may exceed the 689 kpa limit in some local areas. Yet, if insufficient torque is applied to the screws
18
, pressure exerted by the cooling/protective plate
16
on the protruding element
19
of the chip
10
is likely to be too low to provide a good contact for cooling. In addition, vibrations caused by physical impact of the notebook computer may loosen the grip of the cooling/protective plate. Even without any external impact, the pre-loaded pressure provided by the screws
18
just for holding the cooling/protective plate
16
onto the printed circuit board
12
is likely to bring down the shock buffering capacity of the cooling/protective plate
16
.
SUMMARY OF THE INVENTION
Accordingly, the purpose of the present invention is to provide a shock-absorbing device for a notebook computer module. The module is capable of buffering the module against impact forces in both directions and providing a correct amount of contact pressure between the device and a cooling/protective plate.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a shock absorbing device. The device comprises a notebook computer module, a cooling/protective plate, and two springs. There is a first spring between the notebook computer module and the cooling/protective plate, and the notebook computer module and the cooling/protective plate are in contact with each other. The first spring provides a force that tries to separate the cooling/protective plate and the module. The first spring is slid over the body of a balancing rod. A first end of the balancing rod passes through a hole in the cooling/protective plate and a second end of the balancing rod touches the module. There is a fastening insert on the cooling/protective plate as well. The fastening insert passes through another hole in the cooling/protective plate and then fastens onto the module. A second spring is slid between one end of the fastening insert and the cooling/protective plate. The second spring provides a force that tries to bring the cooling/protective plate and a printed circuit board of the module. When the cooling/protective plate that holds the module is fastened onto a substratum, the amount of pressure on the module such as a chip can be adjusted by increasing or decreasing the spring loading. In the meantime, when an external force is exerted on the cooling/protective plate or the entire module is forced to vibrate, the stored potential in the springs can counteract a portion of the external force or vibrations. Hence, the force or the vibration is dampened and so the module inside the notebook computer is saved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 4796849 (1989-01-01), Fouassier
patent: 5331508 (1994-07-01), Hosoi et al.
patent: 5590024 (1996-12-01), Honda et al.
patent: 5999402 (1999-12-01), Jeffries et al.
patent: 6061240 (2000-05-01), Butterbaugh et al.
patent: 0123456 A2 (2000-01-01), None

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