Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1999-04-08
2002-05-21
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C361S788000, C439S061000, C439S065000
Reexamination Certificate
active
06392142
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printed wiring board mounting structure, and, in particular, to a printed wiring board mounting structure which is a part of a communication apparatus, an information processing apparatus, or the like, in which structure a plurality of printed wiring boards are mounted on a back panel side-by-side.
2. Description of the Related Art
FIGS. 1A and 1B
show a printed wiring board mounting structure
10
in the related art which is incorporated into a shelf (not shown in the figures) of a communication apparatus. The printed wiring board mounting structure
10
includes a back panel
11
having a multilayer wiring structure, and a plurality of printed wiring board units
12
. Each unit of the plurality of printed wiring board units
12
includes a printed wiring board
13
on which an LSI circuit
14
, and so forth, are mounted. The plurality of printed wiring board units
12
are connected with the back panel
11
through connectors, and mounted on a front surface
11
a
of the back panel
11
side-by-side, each board unit
12
extending vertically as shown in the figures. The plurality of printed wiring board units
12
are electrically connected by wiring patterns in the back panel
11
.
FIGS. 2A and 2B
show a printed wiring board mounting structure
20
in the related art, which structure is incorporated into a shelf (not shown in the figures) of an information processing apparatus. The printed wiring board mounting structure
20
is used for performing information processing. The structure
20
includes a back panel
21
which has a multilayer wiring structure. The structure
20
further includes a plurality of front-surface-side printed wiring board units
22
which are mounted on, and connected with, the back panel
21
through connectors on a front surface
21
a
thereof, side by side, each unit
22
extending vertically as shown in the figures. The structure
20
further includes a plurality of rear-surface-side printed wiring board units
30
which are mounted on, and connected with, the back panel
21
through connectors on a rear surface
21
b
thereof, side-by-side, each unit
30
extending vertically as shown in the figures. Each of the front-surface-side printed wiring board units
22
includes a printed wiring board
23
on which an LSI circuit
24
is mounted. Each of the rear-surface-side printed wiring board units
30
includes a printed wiring board
31
on which an LSI circuit
32
is mounted. Each of the LSI circuits
24
and
32
includes a driver and a receiver and performs information processing. The plurality of front-surface-side printed wiring board units
22
are connected by wiring patterns provided in the back panel
21
. The plurality of rear-surface-side printed wiring board units
30
are connected by wiring patterns provided in the back panel
21
. The front-surface-side printed wiring board units
22
are connected with the rear-surface-side printed wiring board units
30
by wiring patterns provided in the back panel
21
.
In the printed wiring board mounting structure
20
, the drivers of the LSI circuits
24
transmit instructions and the receivers of the LSI circuits
24
receive the instructions, between the plurality of front-surface-side printed wiring board units
22
. Further, in the printed wiring board mounting structure
20
, the drivers of the LSI circuits
32
transmit instructions and the receivers of the LSI circuits
32
receive the instructions, between the plurality of rear-surface-side printed wiring board units
30
. Further, in the printed wiring board mounting structure
20
, the drivers of the LSI circuits
24
and
32
transmit instructions and the receivers of the LSI circuits
24
and
32
receive the instructions, between the front-surface-side printed wiring board units
22
and the rear-surface-side printed wiring board units
30
.
The printed wiring board mounting structure
10
shown in
FIGS. 1A and 1B
has the following problems:
Recently, as the processing capacities of the respective printed wiring board units
12
increase, an increase in the number of wiring patterns to be provided in the back panel
11
is needed. In order to increase the number of wiring patterns to be provided in the back panel
11
, it is necessary to increase the number of wiring layers of the back panel
11
, or to add a jumper wire
15
shown in FIG.
1
B. When the number of wiring layers of the back panel
11
is increased, the cost for manufacturing the back panel
11
increases considerably. When the jumper wire
15
is added, the reliability of the back panel
11
is degraded.
The printed wiring board mounting structure
20
shown in
FIGS. 2A and 2B
has the following problems:
With reference to
FIG. 3
, transmission of instructions and reception of information between the front-surface-side printed wiring board unit
22
-
1
, the front-surface-side printed wiring board unit
22
-
2
and the rear-surface-side printed wiring board
30
-
1
will now be considered. Instructions from the LSI circuit
24
-
1
of the front-surface-side printed wiring board unit
22
-
1
pass through a path
40
in the back panel
21
and reach the LSI circuit
24
-
2
of the front-surface-side printed wiring board unit
22
-
2
. Information from the LSI circuit
24
-
2
passes through the path
40
and reaches the LSI circuit
24
-
1
. Further, instructions from the LSI circuit
24
-
1
of the front-surface-side printed wiring board unit
22
-
1
pass through a path
41
in the back panel
21
and reach the LSI circuit
32
-
1
of the rear-surface-side printed wiring board unit
30
-
1
. Information from the LSI circuit
32
-
1
passes through the path
41
and reaches the LSI circuit
24
-
1
. Each of the paths
40
and
41
is long.
The fact that each of the paths
40
and
41
is long is an obstacle to improvement in speed of information processing.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a printed wiring board mounting structure which solves the above-described problems.
A printed wiring board mounting structure, according to the present invention, comprises:
a back panel having front-surface-side connectors on the front surface thereof and at least one rear-surface-side connector on the rear surface thereof;
a plurality of front-surface-side printed wiring boards which are mounted on the back panel as a result of connectors provided on the plurality of front-surface-side printed wiring boards being connected with the front-surface-side connectors; and
at least one rear-surface-side printed wiring board which is mounted on the back panel as a result of at least one connector provided on the at least one rear-surface-side printed wiring board being connected with the at least one rear-surface-side connector,
wherein, when seen from the front side of the back panel, the at least one rear-surface-side printed wiring board connected with the at least one rear-surface-side connector crosses the front-surface-side printed wiring boards connected with the front-surface-side connectors.
In this arrangement, the at least one rear-surface-side printed wiring board can act as a part of the back panel. Thereby, it is possible to reduce the number of wiring layers of the back panel. Thus, it is possible to reduce the load borne by the back panel itself. As a result, it is possible to reduce the manufacturing cost. Further, it is not necessary to provide jumper wires, and, thereby, it is possible to improve reliability. Further, when signal processing devices are mounted on the at least one rear-surface-side printed wiring board, the signals are transmitted between the signal processing devices wholly in the at least one rear-surface-side printed wiring board. In this arrangement, in comparison to the related art in which signals are transmitted through the back panel, it is possible to shorten the signal transmission paths, and to improve the signal processing speed.
A server, according to the present invention, is provided with a printed
Hanada Koji
Uzuka Yoshinori
Armstrong Westerman & Hattori, LLP.
Fujitsu Limited
Oliva Carmelo
Reichard Dean A.
LandOfFree
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