Electrical connectors – Including or for use with tape cable – With mating connection region formed by bared cable
Reexamination Certificate
2001-12-03
2003-04-22
Bradley, P. Austin (Department: 2833)
Electrical connectors
Including or for use with tape cable
With mating connection region formed by bared cable
C439S260000
Reexamination Certificate
active
06551128
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a connector for connecting flexible substrates to electrical circuits. E.g., a flexible flat cable (FFC) or a flexible printed circuit substrate (FPC). More specifically, the present invention relates to a connector for connecting flexible substrates that allows a flexible substrate to be connected using low or zero insertion force.
2. Description of the Related Art
Conventionally, flexible substrate connectors serve multiple functions including electrically connecting FFCs and FPCs to each other, providing a relay connection between the two, or electrically connecting either one to a circuit substrate mounting electronic parts.
Since flexible substrates are flexible, flexible substrate connectors typically use a ZIF (zero insertion force) structure. ZIF structures allow flexible substrates to be inserted in a connector with low insertion force without exerting a contact pressure. After the flexible substrate is inserted, contact with the connector's contacts is made using a predetermined contact pressure. This contact provides a stable electrical connection.
In conventional flexible substrate connectors equipped with a ZIF structure, contact sections of multiple contacts extend into an insertion opening of a housing. A slider attaches to the insertion opening and can move forward and back. When the slider is drawn outward from the insertion opening, a space for the insertion of the flexible substrate is provided. This space allows the flexible substrate to be inserted using a low insertion force without receiving contact pressure from the contacts.
After conventional insertion, the slider is inserted into the insertion opening. The slider presses the flexible substrate toward the contact sections, resulting in adequate contact pressure with the contacts. During conventional release, the slider is withdrawn and the space around the flexible substrate allows the flexible substrate to be removed without receiving contact pressure from the contacts.
In this type of conventional connector equipped with a ZIF structure, the slider is inserted along the direction of the flexible substrate. The ZIF structure is thus difficult to use since the flexible substrate gets in the way. Further, difficulty exists since the slider is held from both sides while inserted into or removed from the insertion opening. This insertion or removal requires operating space on either side of the connector. The requirement for additional space limits printed circuit substrate density.
Referring now to
FIG. 9
, a conventional flexible substrate connector
100
including a ZIF structure, employs a pivotable lever
102
in place of the slider described above.
Connector
100
includes a housing
101
formed from an insulative plastic resin and mounted on a printed circuit substrate (not shown). A series of contacts
103
attached to housing
101
. Lever
102
formed from an insulative plastic resin.
Contacts
103
are stamped from a conductive metal plate and each includes a contact section
103
a
, a leg
103
b
and a support
103
c
. Contact section
103
a
is positioned in a cantilevered manner to contact a conductive pattern (not shown) formed on flexible substrate
130
. Leg
103
b
connects with solder to the circuit pattern on the printed circuit substrate(not shown). Support
103
c
engages lever
102
.
Housing
101
includes an insertion opening
104
formed to receive flexible substrate
130
. Each contact
103
is attached at a pitch corresponding to the circuit pattern formed on flexible substrate
130
so that contact section
103
a
extend into insertion opening
104
.
The base end of lever
102
is bent to form a U-shaped cross-section with an inner perimeter surface formed as an arc to engage support
103
c
of contact
103
, and pivot around support
103
c
. An outer perimeter surface of lever
102
is formed with a recessed surface
105
a
and a projected surface
105
b
around the rotation axis of the lever
102
.
During connection, lever
102
is pivoted vertically and flexible substrate
130
is inserted into insertion opening
104
of housing
101
. When flexible substrate
130
is inserted, a lowermost portion of recessed surface
105
a
of lever
102
initially extends into insertion opening
104
. This action forms a space between recessed surface
105
a
and contact section
103
a
of contact
103
a
and allows flexible substrate
130
to be inserted. Flexible substrate
130
can thereby be inserted without receiving initial contact pressure from contact section
103
a.
After flexible substrate
130
is inserted, lever
102
is pivoted to a closed position and projected surface
105
b
presses against the upper surface of flexible substrate
130
. This pressing causing contact section
103
a
to flex downward and results in an elastic contact with a predetermined contact pressure between contact section
103
a
and the conductor pattern of flexible substrate
130
.
During removal, lever
102
is pivoted in the opposite direction to an open position. This pivoting action forms a space in insertion opening
104
so that flexible substrate
130
can be removed without receiving contact pressure from contact section
103
a.
With connector
100
equipped with a ZIF structure and lever
102
, lever
102
can be operated without being obstructed by the now inserted flexible substrate
130
. Since the insertion-removal operation is performed from above connector
100
, there is no need to provide additional operating space on either side of connector
100
.
However, this type of pivoting flexible substrate connector
100
uses the difference in height from the rotation axis between recessed surface
105
a
and projected surface
105
b
. This difference in height allows flexible substrate
130
to press toward contact
103
, providing a predetermined contact pressure with contact section
103
a
. Forming a projected surface
105
b
to provide contact pressure with a large height difference at the base end of lever
102
is difficult. Connector
100
thereby requires either a larger size or a reduction in contact pressure since a large height difference could not be provided.
Lever
102
and flexible substrate
130
only contact along projected surface
105
b
. This minimal contact allows flexible substrate
130
to be easily pulled out with a minimal pulling force. Easy removal of flexible substrate
130
would rotate lever
102
itself, thus requiring a stopper (not shown) to prevent lever
102
from rotating as a safety backup.
Additionally, where contacts
103
are attached with a narrow pitch in housing
101
, contact sections
103
a
are exposed in insertion opening
104
in a longitudinally staggered manner along the insertion direction. Since pressure on flexible substrate
130
is applied only at one position along projected surface
105
b
it is difficult to provide an elastic contact with flexible substrate
130
having uniform contact pressure. Where two different contact types (not shown) are used, uniform elastic contact pressure is very difficult.
An additional negative to this type of design is that action of projected surface
105
b
tends to wear out and distort contact section
103
a
and contacts
103
over time. A final negative to the design is that one side of flexible substrate
130
is dominated by lever
102
thereby providing a design restricting contact sections
103
a
to a single side of flexible substrate
130
.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a connector for providing stable electrical connection between a flexible substrate and a circuit.
It is an object of the present invention to provide a connector for connecting flexible substrates that does not require operating space on either side of a housing.
It is another object of the present invention to provide a device that allows a lever to operate without interference from a flexible substrate.
It is another object of the present invention to provide a device tha
Bradley P. Austin
Darby & Darby
Hammond Briggitte
SMK Corporation
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