Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
1999-08-12
2001-02-13
Abrams, Neil (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
Reexamination Certificate
active
06186797
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a land grid array connector for electrically connecting a CPU to a printed circuit board.
2. The Prior Art
Land grid array (LGA) connectors are commonly used with IC packages and do not require soldering procedures during engagement between the LGA connector and a related printed circuit board (PCB). Normally, an LGA assembly includes an IC package having a plurality of flat contact pads formed on a bottom surface thereof, a connector having an insulative housing and defining a plurality of passageways therethrough, and a plurality of conductive contacts received in the passageways of the connector. Fastening means consisting of a top plate positioned on a top surface of the IC package, a bottom plate positioned on a bottom surface of the PCB, and a plurality of sets of aligned holes defined through the PCB, the top plate and the bottom plate is used to configure the assembly. Each set of aligned holes receives a screw therein which engages with a washer and a nut thereby sandwiching the LGA assembly between the top and bottom plates of the fastening means.
U.S. Pat. No. 5,653,598 discloses an electrical contact for use in a connector
30
between mutually opposed electrical interfaces
40
,
99
such as contact pads respectively formed on an IC package
2
and a printed circuit board
9
, as shown in FIG.
12
. The conventional contact comprises a generally planar contact body
10
having first and second major faces
110
,
120
. The body includes a pair of spaced apart spring arms
140
,
150
connected by a resilient bight portion
160
. The spring arms
140
,
150
each have a free end with an outwardly facing edge forming a contact nose
17
,
18
for engaging with the corresponding interface
40
,
99
. Shorting sections
19
,
20
generally extend toward each other from the free ends and are offset such that, upon deflection of the spring arms
140
,
150
toward each other, the shorting sections
19
,
20
overlap and the first major face
110
engages the second major face
120
. Thus, a shortened electrical path is formed between the contact noses
17
,
18
when the package
2
is urged against the connector
30
.
The electrical interface
40
of the IC package
2
may not be able to properly abut against the contact nose
17
of the contact body
10
due to misalignment when the IC package
2
and the printed circuit board
9
are forced to sandwich the connector
30
by a clip or screws. Therefore, it is requisite to provide a positioning structure on the connector to effectively fix the IC package in the connector before an external clamping force is applied on the IC package via the IC package and the printed circuit board.
Moreover, the shorting sections
19
,
20
may not properly contact each other due to unwanted lateral deflection thereof when the bight of the contact is deformed. Although the inner wall of the passageway receiving the contact may be used to limit the lateral deflection of the shorting sections
19
,
20
, unwanted scraping of the shorting sections
19
,
20
against the inner wall of the passageway may occur thereby adversely affecting the proper overlap of the two shorting sections
19
,
20
. Proper overlap and engagement of the two shorting sections
19
,
20
is difficult to achieve with this structure. Moreover, an additional contact resistance exists between the shorting sections
19
,
20
thereby adversely affecting the signal transmission. Additionally, the spring arms
140
,
150
occupy too much space especially in the length thereof which causes impossible for fine pitch requirement. It is requisite to provide a new LGA contact which can provide a relatively short transmission path without introducing an additional contact resistance between shorting sections of the contact.
SUMMARY OF THE INVENTION
The primary purpose of the present invention is to provide a new LGA contact which can achieve relatively short transmission path without the requirement of shorting sections.
Another purpose of the present invention is to provide a new LGA connector which can achieve relatively short transmission path by the contacts thereof without introducing additional contact resistance inside the connector.
In accordance with one aspect of the present invention, a contact comprises a central torsion beam, two side plates integrally connected to two ends of the central torsion beam and each side plate is perpendicular to the torsion beam. Two curved spring arms extend oppositely from a center portion of the torsion beam so that when the side plates are fixed in position and the curved spring arms are exerted opposite forces by two contact pads sandwiching the contact, the torsion beam will be twisted for a predetermined angle to transmit reactive forces to the curved spring arms to abut against the contact pads.
In accordance with another aspect of the present invention, a land grid array connector comprises an insulative housing having a plurality of passageways defined therein, each passageway having a longitudinal wide hole and a lateral narrow hole communicating with and perpendicular to the longitudinal wide hole. A plurality of contacts are respectively received in one of the passageways. Each contact comprises a torsion beam substantially received in the intersection of the longitudinal wide hole and the lateral narrow hole of the passageway, two engagement plates connected to two ends of the torsion beam and fittingly retained in the lateral narrow hole of the passageway, two curved spring portions extending oppositely from a central section of the torsion beam and each curved spring portion having a free contacting portion extending out of the passageway. When the free contacting portion of each curved spring portion of the contact is depressed by a contact pad of an external electrical device, the torsion beam is twisted for a predetermined angle to force the free contacting portion to abut against the contact pad.
REFERENCES:
patent: Re. 35733 (1998-02-01), Hernandez et al.
patent: 5380210 (1995-01-01), Grabbe et al.
patent: 5395252 (1995-03-01), White
Hsiao Shih-Weu
Lin Nick
McHugh Robert G.
Wang Jaomin
Abrams Neil
Chung Wei Te
Hon Hai - Precision Ind. Co., Ltd.
Nasri Javaid
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