BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the art of electrical connectors, and more particularly to a land grid array (LGA) socket having electrical terminals for electrically connecting two separate electronic components.
2. The Prior Art
A conventional land grid array (LGA) socket 6 is illustrated in FIGS. 6-7, the socket 6 basically comprises an insulative housing 60 having a plurality of passageways formed therein, each passageway receives an electrical terminal 62 therein. The terminal 62 includes a base portion for securing the terminal 62 in the passageway and a pair of spring arms 622 and 624 respectively extending out of opposite surfaces of the housing 60 and resisting two separate electronic components 7 and 8 so as to establishing electrical connection between the two components 7 and 8.
Referring to FIG. 7, while the electronic components 7 and 8 are down to their final position, a height H between the components 7 and 8 are normally unchangeable in order to maintain a sufficient pressing force between the spring arms 622 and 624 as desired by establishing successfully electrical connection. However, under some particular design consideration, there is a need to increase the height H. Consequently, the base portion 620 of the terminal 62 has to be elongated such that the whole length of the terminal 6 can satisfy the requirement of the increased height H. As a result, the die for manufacture of the terminal 62 has to be modified to make a different configuration, which increases the overall cost of the LGA socket 6 and makes the manufacture process of the LGA socket become relatively complicated.
Further, the LGA socket is often used to transmit high frequency signals, which requires the terminals used in the socket have a relatively high capacitance and a relatively low impedance. However, the terminal 62 as disclosed in FIGS. 6 and 7 has a very simple configuration and its low capacitance and high impedance cannot fulfill the requirement of high frequency signal transmission. Therefore, there is a need to invent an improved terminal to resolve the above-mentioned shortcomings.
SUMMARY OF THE INVENTION
Accordingly, a main object of the present invention is to provide an land grid array (LGA) socket having an improved terminals, wherein the terminals simplify manufacture of the LGA socket and ensure desired high frequency signal transmission.
To fulfill the above-mentioned object, a land grid array socket in accordance with the present invention is provided. The socket comprises an insulative housing having a plurality of passageways extending throughout an upper mating surface and a lower mounting surface. A plurality of electrical terminals are received in corresponding passageways, each terminal comprises a first part having a first spring arm extending out of the upper mating surface for electrically connected to an IC chip and a second spring arm extending out of the lower mounting surface for electrically connected to a motherboard. The first part and the second part are accommodated in a same passageway and separate from each other while interconnected by a third spring arm settled therebetween. According to one embedment of the present invention, the third spring arm functions as a bridge portion and extends from a second base portion of the second portion toward a first base portion of the first part and resists a main plane of the first base portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an perspective view of an electrical terminal of a land grid array (LGA) socket in accordance with a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the terminal of FIG. 1 being received in an insulative housing of the LGA socket, before an IC chip and a mother board establish electrical connection with the terminals.
FIG. 3 is similar to FIG. 2, showing the state after the IC chip and the mother board establish electrical connection with the terminals.
FIG. 4 is an perspective view of an electrical terminal in accordance with a second embodiment of the present invention.
FIG. 5 is an perspective view of an electrical terminal in accordance with a third embodiment of the present invention.
FIG. 6 is an perspective view of a conventional LGA terminal.
FIG. 7 is an cross-sectional view of a conventional LGA socket.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Reference will now be made to the drawings to describe the present invention in detail.
Referring to FIGS.1 and 2, a land grid array (LGA) socket 1 in accordance with a first embodiment of the present invention is illustrated. The socket 1 comprises an insulative housing 1 having a plurality of passageways 24 formed therein, each passageway 24 extends throughout a mating surface 22 and a mounting surface 20 of the housing 2 and accommodates an electrical terminal 3 therein. The terminal 3 has springs arm respectively extending out of the mating surface 22 and the mounting surface 20 for electrically connecting with a first electronic component above the mating surface 22 and a second electronic component under the mounting surface 20. In this embodiment, the spring arms respectively connect with contacting pads 40 of an IC chip 4 and contact pads 50 of a motherboard 5.
Referring to FIG. 1, the terminal 3 comprises a first part 32 and a second part 30, the two parts 32 and 30 are separate from each other. The first part 32 comprises a first base portion 320 which has a planar main plane 3202 and a pair shoulders 3200 for securing into a slot in an inner wall of the passageway 24. A first spring arm 322 extends out upwardly from one upper end of the base portion 320, and the first spring arm 322 forms a first contacting end 3220 in a free end thereof which resists the contacting pad 40 of the IC chip 4 when the terminal 3 is received in the passageway 24. The second part 30 comprises a second base portion which includes a end wall 300 and a side wall 302 vertically bending from one side of the end wall 300. A second spring arm 306 extends out downwardly from one lower end of the end wall 300, and the second spring arm 306 forms a second contacting end 3060 in a free end thereof which resists the contacting pad 50 of the motherboard 5 when the terminal 3 is received in the passageway 24. A third spring 304, functioning as a bridge portion, extends out from one side of the side wall 302 and forms a third contact end 3040 which resists the main plane 3202 of the first base portion 320 when the terminal 3 is received in the passageway 24. Thus, electrical connection between the first part 32 and the second part 30 of the terminal 3 is established via the bridge portion 304 settled therebetween.
Referring to FIG. 3, when the IC chip 4 and the motherboard 5 all press down to its final electrical connecting position and contact with the spring arms 322 and 306, a vertical height between the two spring arms 322 and 306 is determined. Because of relatively simple structure of the first part 32, it is easy to downwardly insert the base portion 320 of the first portion 32 to a deeper position in the passageway 24 along the slot in the inner wall of the passageway 24, or upwardly pull the base portion 320 of the first portion 32 out of the passageway 24 to a shallower position in the inner wall of the passageway 24 along the slot. Thus, desired modification of the vertical height is easily reached without any design change on the terminal 3 and the housing 2, which will greatly decrease the whole manufacturing cost of the socket 1.
Referring to FIG. 4, an electrical terminal 3′ in accordance with a second embodiment is illustrated, a second part 30′ of the terminal 3′ comprises a end wall 300′ and a pair of side walls 302′ vertically bending from opposite sides of the end wall 300′, respectively. Thus, when the terminal 3′ is received in the passageway 24 of the housing 2, the end wall 300′, the side walls 302′ and the first base portion 320′ of the first part 32′ surround a substantially encircled inner space. The settling of the inner space increases the capacitance of the terminal 3′ as well as decreasing the impedance of the terminal 3, which greatly benefits high frequency signal transmission.
Two preferred embodiments in accordance with the present invention have been shown and described. However, in another alternative embodiment as shown in FIG. 5, a vertical length H″ of the second base portion 30″ of the terminal 3″ is longer than a vertical length H′ of the second base portion 30′ of the terminal 3′, this kind of modification can also modify the high frequency characteristic of the terminal to its desired level. Further, in another alternative embodiment, the third spring arm can also be set on the first base portion of the first part or other place in the passageway, if only it can function as a bridge portion to interconnect the first and second parts of the terminal. Therefore, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present invention are considered within the scope of the present invention as defined in the appended claims.
Patent Application
20050227511
