Contact structure in socket with IC carrier placed thereon

Abstract: A contact structure has an IC carrier (1) for holding an IC package (8) which is placed on a socket (10) and contact pieces (9) which are to be contacted with contacts (11) of the socket. The contact structure in the socket includes contact pieces (11b) for allowing the contacts to be contacted with IC contact pieces (9) from thereabove and under pressure and the IC carrier (1) is held between the socket (10) and the IC package (8) by pressure contact force which is exerted on the IC contact pieces (9) by the contact pieces (11b) of the contacts (11) of the socket.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a contact structure in a socket with an IC carrier placed thereon in which an IC package is held by the IC carrier and the IC carrier is placed on the IC socket in order to obtain a contact relation between the IC package and the IC socket. 2. Brief Description of the Prior Art In general, an IC carrier holds an IC package in such a manner as that contact pieces of the IC package are supported on an upper surface of a flat square frame and engaging claws are engaged with an edge portion of an IC package body. Heretofore, there have been widely employed contact systems in which the IC package is placed on the socket together with the IC carrier without removing the IC package from the IC carrier in order to obtain a contact relation between the socket and the IC contact pieces. In the prior art, the IC carrier for holding the IC package is inverted and placed on the socket in such a manner as that the IC contact pieces and the upper surface of the frame are faced downward, said IC contact pieces being placed on the contacts arranged within the socket, the IC carrier being urged against the socket by a presser plate provided to the socket, so that the IC carrier is held by the socket by the pressing force and contact pressure between the contacts and contact pieces is obtained. In such conventional socket with an IC carrier placed thereon as mentioned above, the IC carrier must be inverted each time when it is loaded on the socket and opening and closing operation of the presser plate and a lock lever must be carried out. Accordingly, it is difficult to automate the loading operation. Furthermore, as the IC package is sandwiched between the IC carrier and the socket and the presser plate is put thereon to cover, heat radiation of the IC package is badly decreased. Although there is another device in which the carrier has the function of a presser plate, as strength is required for the carrier, weight is increased and an external configuration becomes large. Therefore, no improvement is made in respect of hindrance of heat radiation. US-A-4,691,975 describes a socket for testing integrated circuits in which the IC is held in the socket without the support of an IC carrier. The socket has resilient clamping contact pieces for engaging unsupported contacts of the IC. SUMMARY OF THE INVENTION It is therefore a general object of the present invention to provide a contact structure in a socket with an IC carrier placed thereon which is capable of solving the above-mentioned problems and which is extensively simplified. In order to achieve the above object, there is provided a contact structure in accordance with Claim 1. From an embodiment of the present invention, there is provided a contact structure in which an IC carrier for holding an IC package is placed on a socket and contact pieces of said IC package held by said IC carrier are contacted with contacts of said socket, said contact structure in said socket with said IC carrier placed thereon being characterized in that a frame of said IC carrier for supporting IC contact pieces of said IC package is provided with holes or grooves corresponding to said contact pieces, each of said contacts being provided with a first contact piece adapted to contact with said IC contact piece from thereabove and a second contact piece adapted to contact with said IC contact piece from thereunder through said hole or groove, said IC contact piece being pinched by said first contact piece and said second contact piece so that said IC package is held, thereby to hold said IC carrier between said socket and said IC package. According to the present invention, the IC carrier holding the IC package is placed on the socket without being inverted. In the foregoing state, the contacts of the socket are contacted with the IC contact pieces from the upper surface side of the IC carrier and a pressing force accompanied by the contact is exerted to the IC carrier through the contact pieces. As a result, the IC carrier maintains the above-mentioned contact relation by being held on the socket by the pressing force of the contacts while permitting the IC package to be contacted with the socket. Even if the contact structure of the present invention is constructed such that while contacting the IC contact pieces with the first contact pieces of the contacts from thereabove, the second contact pieces are contacted with the IC contacting pieces from thereunder through holes or grooves formed in the frame of the IC carrier in order to hold the IC contact pieces, IC carrier can be held by holding the IC package and a highly reliable contact relation can be obtained by the first contact pieces and the second contact pieces. Other objects and advantages of the present invention will become more apparent during the course of the following description when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 through 7 show a first embodiment of the present invention, Fig. 1 is a perspective view, partly in section, showing an IC carrier, Fig. 2 is a perspective view, partly in section, showing the IC carrier with an IC package loaded thereon, Fig. 3 is a view showing the IC carrier immediately before it is loaded on the socket, Fig. 4 is a view showing a state where a contact opening and closing member is pressed down and the contact is moved backward and upward, Fig. 5 is a view showing a state where stopping of the pressing down operation of the contact opening and closing member is started and a contact portion of the contact is contacted with a tapered portion of the IC carrier, Fig. 6 is a view showing a state where the pressing down operation has been completely stopped and the contact portion climbs over the tapered portion and is contacted with the IC contact piece, and Fig. 7 is a view showing another example of the IC carrier. Figs. 8 through 10 show a second embodiment of the present invention, Fig. 8 is a perspective view of the IC carrier having a groove formed thereon, Fig. 9 is a perspective view of the IC carrier having holes formed in the frame, and Fig. 10 is a sectional view of the socket on which the IC carrier is placed in order to obtain a contact relation. DETAILED DESCRIPTION OF THE EMBODIMENT The embodiments of the present invention will be described in detail hereunder with reference to Figs. 1 through 10. First Embodiment (see Figs. 1 through 7) The reference numeral 1 denotes an IC carrier formed of a generally square frame and a generally square IC package accommodating portion 2 is formed in a central area defined by the frame. The IC carrier is provided with engaging claws 3 each of which is formed on an angular portion of each end of one of the diagonal lines and adapted to hold the IC package 8 on the IC carrier 1. An angular portion of each end of the other diagonal line is provided with a U-shaped groove 4 adapted to deform the IC carrier 1 against the resiliency with reference to the diagonal line as an axis. That is, by virtue of the provision of the U-shaped groove 4, the bottom wall of the U-shaped groove 4 can be formed thin to form a hinge bendable along the diagonal line at the thin portion thereby to make it possible to bend the IC carrier. Also, an upper surface of the frame of the four sides around the IC package accommodating portion 2 has a projection 5 extending in the extending direction of the frame and adapted to position the IC package 8. A tapered portion 6 is formed on an outer edge side of the projection 5 in such a manner as to become a downward gradient toward outer side, and a contact piece supporting seat 7 is formed between the tapered portion 6 and the projection 5. Fig. 2 shows a state where the IC package 8 is held by such constructed IC carrier 1 as mentioned above. The IC package 8 has a number of contact pieces 9 projecting sideward from its four sides. Each of the contact pieces 9 is bent in a generally hook shape at its inner side and bent in a generally reversed hook shape at its leading end side. When the IC package 8 is accommodated in the accommodating portion 2 of the IC carrier 1, the projection 5 is located within the generally hook-shaped bent portion on its inner side and the generally reversed hook-shaped bent piece on its leading end side is supported by the contact piece supporting seat 7. The retaining claws 3 are engaged with the angular portions of the IC package 8 so that the IC package 8 is held by the IC carrier 1. In order to have the IC package 8 held by the IC carrier 1, the IC carrier 1 is bent along the U-shaped grooves 4 to open the engaging claws 3 and after the IC package 8 is accommodated, the IC carrier 1 is restored to cause the retaining claws 3 to be engaged with the edge portion of the IC package 8. Next, in order to obtain a contact relation by placing the IC carrier 1 holding the IC package 8 on the IC socket 10, first in the state of Fig. 3, the opening and closing member 12 held by the IC socket 10 is pressed down to form a backwardly and upwardly moved state of the contact 11 against the resiliency. The contact 11 has a contact portion 11a at an upper end portion of a curved spring piece forming the contact piece 11b and an arm 11c extending backward from the upper end portion of the curved spring piece. The contact 11 is moved backward and upward by pressing down the arm 11c by the contact opening and closing member 12. Next, as is shown in Fig. 4, the IC carrier 1 holding the IC package 8 is accommodated in the IC carrier accommodating portion 15 opened in the central portion of an upper surface of the IC socket 10 and the IC carrier 1 is placed on the supporting wall 10a at the inner bottom of the IC carrier accommodating portion 15. The supporting wall 10a is provided with a positioning wall 13 adapted to regulate the inner surface of the frame of the IC carrier 1 so that the IC carrier is positioned. Next, as is shown in Figs. 5 and 6, when the press down force exerted to the contact opening and closing member 12 is removed, the contact 11 is restored against the resiliency and the contact portion 11a is caused to slide and climb over the tapered portion 6 in order to resiliently contact with the IC contact piece 9 from thereabove. In this way, the IC contact piece 9 of the IC package 8 can obtain a favorable electric contact from the above of the contact 11 by means of pressure contact and the pressing force of the contact 11 is exerted to the frame of the four sides of the IC carrier 1 so that the IC carrier 1 is held by the socket 10. As is shown in Fig. 7, it may be designed such that the frame of the IC carrier 1 is not provided with the tapered portion 6, and the contact portion 11a of the contact 11 is moved backward in such a manner as to move the contact 11 upward so that the contact portion 11a, when returning, directly contacts with the contact piece 9 from thereabove without through the tapered portion 6. In order to cancel the contact relation between the contact 11 and the IC contact piece 9, the contact opening and closing member 12 is pressed down again and the IC carrier 1 is removed in a state where the contact 11 is moved backward and upward. As the socket of Figs. 3 through 7 is laterally symmetric, the other half part is omitted from the drawings. Second Embodiment (see Figs. 8 through 10) In this embodiment, the contact piece supporting seat 7 of the IC carrier 1 described in the first embodiment is provided with a groove 14 (see Fig. 8) laid along the frame or with holes 14′ (see Fig. 9) corresponding to the IC contact pieces 9. On the other hand, as is shown in Fig. 10, the contact 11 is provided with a first contact piece 11b adapted to contact at its contact portion 11a with the IC contact piece 9 from thereabove and a second contact piece 11d adapted to contact at is contact portion 11e with the IC contact piece 9 from thereunder through the hole 14′ and the groove 14. A pressing down force of the first contact piece 11b is made larger than a pushing up force of the second contact piece 11d so that the IC carrier 1 is held between the socket 10 and the IC package 8 by the pressing down force exerted to the contact piece 9 of the first contact piece 11b. At the same time, the IC contact piece 9 is vertically held between the first and the second contact pieces 11b and 11d in order to obtain a favorable contact relation. In other words, in the case of this embodiment, the IC contact piece 9 is held between the first and the second contact pieces 11b and 11d so that the IC package 8 held by them, thereby to hold the IC carrier 1 between the IC package 8 and the socket 10. Also, it may be designed such that when the IC carrier 1 is placed on the socket 10, the contact portion 11e of the second contact piece 11d is slightly projected upward from the hole 14′ or the groove 14 and the IC contact piece 9 is held between the first and the second contact pieces 11b and 11d, thereby the IC carrier 1 is interposed between the IC package 8 and the socket 10 in order to hold the same. In this case, the IC carrier 1 may be interposed with a small amount of play. As described in the foregoing, according to the present invention, the IC carrier holding the IC package can be placed on the socket without inverting the IC carrier and in the foregoing state, a favorable contact relation can be obtained between the contact of the socket and the IC contact piece of the IC package. At the same time, a pressing force of the contact for contacting with the IC contact piece from the upper surface side of the carrier is exerted to the IC carrier through the contact piece. As a result, the IC carrier is held on the socket by means of the pressing force of the contact. That is, the IC carrier holds the IC package at the opened upper surface of the socket to as to be ready for contacting and the socket is held by the contact for contacting. Also the same function and effect can be obtained even if it is designed such that the first contact piece of the contact is caused to contact with the IC contact piece from thereabove, and the second contact piece is caused to contact with the IC contact piece from thereunder through the holes or grooves formed in the frame of the IC carrier. Therefore, a highly reliable contact relation can be obtained by the first and the second contact pieces. Furthermore, as there can be employed such a structure as that the IC carrier is placed on the socket without inverting the IC carrier and the contact is moved to an upper surface of the IC contact in order to obtain a contact relation therebetween thereby to hold the IC carrier, automation for obtaining a contact relation and cancellation of the contact relation becomes very easy. In addition, as the IC package is caused to contact with the socket in its opened state with respect to the socket, the heat radiation effect is very favorable. As the IC carrier itself having an IC carrier functioning as a presser plate is not required strength as in the prior art, it can contribute to make the IC carrier small in size and light in weight.

Claims: A contact structure comprising an IC package, an IC carrier and an IC socket, in which said IC carrier (1) for holding said IC package (8) is placed on said IC socket (10) and contact pieces (9) of said IC package (8) supported by said IC carrier (1) are contacted with contacts (11) of said IC socket, characterized in that said IC socket (10) has a supporting wall structure (10a) on which said IC carrier (1) and said contact pieces (9) are seated with the IC carrier (1) sandwiched between said contact pieces (9) and said supporting wall structure (10a) and in that said contacts (9) are adapted to have contact portions (11a) which, when engaged with said contact pieces (9) to make contact therewith, exert a force on said contact pieces (9) so as to clamp both the contact pieces (9) and the IC darrier (1) firmly against the seat provided by said supporting wall structure (10a). A contact structure according to Claim 1 wherein a frame of said IC carrier (1) for supporting IC contact pieces (9) of said IC package (8) is provided with holes or grooves (14,14′) corresponding to said contact pieces, each of said contacts (11) associated with the socket, being provided with a first contact piece (11b) adapted to contact with said IC contact piece (9) from above and a second contact piece (11d) adapted to contact with said IC contact piece from thereunder through said hole or groove, said IC contact piece being pinched between said first contact piece and said second contact piece so that said IC package is gripped, thereby to hold said IC carrier (1) between said socket (10) and said IC package (8). A contact structure according to Claim 1 or Claim 2 wherein said contacts (11) of said socket (10) are adapted to be movable between engageable, operative positions in which they contact said IC contact pieces (9) respectively, and disengaged, withdrawn positions in which the IC carrier (1) and IC package assembly (8) can be freely inserted or removed from said socket (10), manually operable means (12) being provided for causing said contacts to move between said operative and withdrawn positions. A contact structure according to Claim 3 wherein said manually operable means include a frame-like control member (12) superimposed on the socket (10) for relative movement towards and away from the socket, the control member and said socket contacts having interengaging portions (11c) shaped to cause withdrawal of the socket contacts on movement of the control member (12) in a direction towards the socket. A contact structure according to any one of Claims 1 - 4 wherein each socket contact (11) has a base portion and a contact portion (11a) which are connected by a curved spring piece (11b) adapted to resiliently urge the contact portion (11a) into engagement with the respective IC contact piece (9).

Inventors: MATSUOKA NORIYUKI, MATSUOKA, NORIYUKI
Applicants: YAMAICHI ELECTRIC MFG, YAMAICHI ELECTRONICS CO., LTD.
Application year: 1990
Main classification: H05K7
IPC codes: H05K7, H01R13, H01R33