JPH053064A - Surface mount type socket for integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the thickness of a base with no degradation of supporting strength of a contact spring for the base. CONSTITUTION:A terminal piece 2b of a contact spring 2 is formed stepwise. On both sides of a fixing piece 21, to be fixed to a base 1, of a terminal piece 2, projections 24 for press fitting are provided respectively. The width of a bridging piece 22, connecting a connection piece 23 to be soldered to a printed circuit board to the fixing piece 21, is specified to be smaller than the distance between tips of both projections 24. On the base 1, press fit grooves 1a provided with a 1st. groove 11 and a 2nd groove 12 of different width to press fit the fixing piece 21 and the bridging piece 22 respectively are formed. The contact spring 2 is press fitted in the base 1 at two positions, so a high fixing strength can be obtained. And as the press fit grooves 1a can be formed so as to be opened to a facing plane of a cap frame and a side wall, the wall facing to the cap frame can be opened to reduce the thickness of the base 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a thin SO
The present invention relates to a surface mount type socket for an integrated circuit suitable for mounting a surface mount type integrated circuit such as P on a circuit board.

[0002]

2. Description of the Related Art Conventionally, as a surface-mounting socket for an integrated circuit of this type, a base on which the integrated circuit is mounted and a holding frame which is fitted on the base and holds the integrated circuit between the base and the base are provided. Be prepared. On the periphery of the base, a large number of contact springs in which a contact piece on which the leads of the integrated circuit are placed and a terminal piece mounted on the circuit board are integrally connected are arranged. That is, the leads of the integrated circuit are placed on the contact pieces, and by sandwiching the leads between the contact pieces and the peripheral portion of the holding frame, the leads are brought into contact with the contact spring in an electrically stable state. Let them do it. Here, as shown in FIG. 13, one end of the contact spring 2 is press-fitted into a press-fitting hole 7 that is opened in the side surface of the base 1.

[0003]

By the way, in recent years, surface-mounting type integrated circuits having a thickness less than half that of conventional integrated circuits have been provided, and the surface-mounting type socket having the above-mentioned conventional structure is integrated in this kind. When it is applied to a circuit, the following problems occur. That is, since the thickness of the integrated circuit is small, the height of the surface mount socket is also required to be small (for example, 3 mm). However, since the press-fitting hole 7 opened to the side surface of the base 1 is used for fixing the contact spring 2, in order to secure the holding strength of the contact spring 2 in the thickness direction of the base 1, the base 1 is secured. There is a problem that the thickness becomes large, and as a result, the height cannot be reduced.

An object of the present invention is to solve the above problems, and by changing the connecting structure of the contact spring to the base, the thickness of the base can be reduced while securing the holding strength of the contact spring to the base. It is intended to provide a surface mount socket for an integrated circuit which can be manufactured.

[0005]

According to the present invention, in order to achieve the above object, a rectangular base made of an insulating material on which a thin surface mounting type integrated circuit is mounted and a lead of the integrated circuit are contacted. Along the circumference of the base, a large number of contact springs are formed in a shape in which one ends of the contact piece and the terminal piece to be soldered to the circuit board are integrally connected and are arranged in a row on the circumference of the base. For an integrated circuit, which has a rectangular frame shape and is mounted on the contact piece and is fixed at a fixed position with respect to the base and holds each lead of the integrated circuit between the contact piece and the holding frame. In the surface mount type socket, the terminal piece of the contact spring has a fixed piece connected to the contact piece, a connection piece soldered to the circuit board, and the fixed piece and the connection piece are substantially parallel to each other. The connection piece is closer to the circuit board than the fixed piece in the thickness direction of the base. It is equipped with a bridging piece that connects so that it is positioned, and press-fitting projections are provided on both sides of the fixed piece, and the distance between the tips of both press-fitting projections is set larger than the width of the bridging piece. The base is provided with a large number of press-fitting grooves that are open to the surface facing the pressing frame and the side surfaces and into which the fixing piece and the bridging piece are press-fitted, and the fixing piece is press-fitted into each press-fitting groove. A first groove portion that is a portion that is narrower than the distance between the tips of the two press-fitting protrusions, and a second portion that is a portion where the bridging piece portion is press-fitted and that is narrower than the width of the bridging piece portion. The groove is
They are formed side by side in the thickness direction of the base.

[0006]

According to the above structure, the terminal piece of the contact spring is bent in a stepwise manner, and the press-fitting protrusions are provided on both side surfaces of the fixing piece portion which is a portion fixed to the base of the terminal piece, Also,
The width of the bridging piece portion is set to be narrower than the distance between the tips of both press-fitting projections, and the first groove portion and the first groove portion having different widths into which the fixing piece portion and the bridging piece portion are press-fitted are formed on the base. Since the press-fitting groove having the two groove portions is formed, the contact spring is press-fitted into the base at two places, and high fixing strength can be obtained. As a result, the press-fitting groove can be formed in the base so as to be open to the side facing the pressing frame and the side surface, and the thickness of the base can be reduced by opening the side facing the pressing frame. It can be made smaller.

[0007]

(Embodiment 1) As shown in FIGS. 2 to 5,
A large number of recesses 1a into which the contact springs 2 are press-fitted and fixed are formed on two sides of a rectangular base 1 made of an insulating material. In addition, a pair of projecting pieces 1b is provided on each of the two sides of the base 1 where the recess 1a is not formed, from each side surface, and a positioning projection 1c is provided above at a position corresponding to the base of each projecting piece 1b. To be done. Further, at the four corners of the base 1, projections 1d having a substantially L-shaped horizontal cross section are provided. The positioning protrusion 1c is provided for positioning the holding frame 3 with respect to the base 1 by engaging the holding frame 3 that holds the integrated circuit 4 with the base 1.
Are provided for positioning the integrated circuit 4 with respect to the base 1 by bringing the four corners of the integrated circuit 4 into contact with each other.

Each contact spring 2 comprises a contact piece 2a and a terminal piece 2b which are separated from each other in the thickness direction of the base 1. One end of each of the contact piece 2a and the terminal piece 2b projects from the peripheral surface of the base 1 and the other end thereof. They are integrally and continuously press-fitted and fixed in the recess 1a of the base 1 so that they are substantially U-shaped. As shown in FIG. 4A, leads 4a protruding from two side surfaces of the integrated circuit 4 are placed on the contact pieces 2a, and the terminal pieces 2b are surface-mounted on the circuit board 6 made of a printed board. .. put it here,
The tip of the contact piece 2a is bent toward the integrated circuit 4,
The contact piece 2a is bent when it comes into contact with the lead 4a of the integrated circuit 4, so that a large contact pressure can be obtained between the contact piece 2a and the lead 4a. This further stabilizes the electrical contact state between the contact spring 2 and the lead 4a.

The contact spring 2 will now be described in more detail. As shown in FIG. 1, the terminal piece 2b of the contact spring 2 has a stepped shape in which the fixed piece portion 21, the bridging piece portion 22 and the connection piece portion 23 are integrally connected in order from the connection portion with the contact piece 2a. The press-fitting protrusions 24 are provided on both side surfaces of the intermediate portion of the fixed piece portion 21, respectively. The fixed piece 21 and the connection piece 23 are substantially parallel to each other, and the bridging piece 22
Is formed so as to obliquely intersect the fixed piece portion 21 and the connection piece portion 23. The press-fitting projection 24 is formed so that the amount of protrusion increases from the fixed piece portion 21 toward the connection piece portion 23, and the end surface on the connection piece portion 23 side is substantially orthogonal to the side surface of the fixed piece portion 21. The width c ₁ of the bridging piece 22 is
It is set to be smaller than the distance b ₁ between the tips of both press-fitting protrusions 24.

On the other hand, the press-fitting groove 1a formed in the base 1 so that the terminal piece 2b is press-fitted has a two-step width of the first groove portion 11 and the second groove portion 12 in the thickness direction of the base 1. And the second groove portion 12 near the circuit board 6 is the first groove portion 1
It is narrower than 1. Also, the width b of the first groove portion 11
₂ is smaller than the distance b ₁ between the tips of the press-fitting protrusions 24 (b
₁ > b ₂ ) and the width c ₂ of the second groove portion 12 is set smaller than the width c ₁ of the bridging piece portion 22 (c ₁ > c ₂ ). The fixed piece portion 21 is press-fitted into the first groove portion 11, and the second groove portion 1
The bridging piece portion 22 is press-fitted into the terminal 2, and the terminal piece 2
Since b is fixed at two places, the fixing strength of the contact spring 2 with respect to the base 1 is increased. Further, since the second groove portion 12 is opened to the surface and the side surface of the base 1 facing the circuit board 6, the connecting piece portion 23 is provided to the surface of the base 1 facing the circuit board 6 through the second groove portion 12. It is exposed.

By fixing the contact spring 2 to the base 1 as described above, the fixing strength of the contact spring 2 to the base 1 is increased, and the surface of the press-fitting groove 1a facing the pressing frame 3 is opened. Even though
The contact spring 2 can be held with sufficient strength. As a result, the thickness of the base 1 can be made smaller than before, and the height can be made smaller. Further, as compared with the case where the press-fitting hole is formed in the base 1 as in the conventional case, the shape of the mold becomes simpler and the slide core becomes unnecessary, which has an advantage that the cost of the mold can be reduced.

As shown in FIG. 4, the integrated circuit 4 is mounted on the base 1 holding the contact spring 2 as described above.
As shown in (b), a rectangular frame-shaped pressing frame 3 is fitted so as to sandwich the lead 4a between the contact piece 2a and the contact piece 2a. A positioning groove 3a with which the positioning protrusion 1c of the base 1 engages is formed on the inner side surface of the pressing frame 3, and the positioning protrusion 1c and the positioning groove 3a engage with each other, whereby the pressing frame 3 is displaced relative to the base 1. Is prevented. Further, on the outer side surface of the pressing frame 3, the engaging protrusions 3 are provided at the four corners corresponding to the side surface of the base 1 different from the side surface from which the contact spring 2 projects.
b is projected.

By the way, the holding pieces 5a of the holding fittings 5 face the two side surfaces of the base 1 on which the contact springs 2 are not projected. The holding metal fitting 5 includes a holding piece 5 a along the side surface of the base 1, and a pair of leg pieces 5 projecting from the vicinity of the center between both ends of the holding piece 5 a along the lower surface of the base 1.
It is formed by sheet metal in a shape in which b is integrally connected.
A burring coupling hole 5c is formed in the center of the leg piece 5b so as to project upward. On the other hand, base 1
As shown in FIG. 5, on the back surface of each projecting piece 1b, a connecting recess 1f having a boss 1e projecting in the center thereof is formed. The metal fitting 5 can be joined to the base 1 by sandwiching the boss 1e into the coupling hole 5c and pressing the boss 1e into the coupling hole 5c. Here, the leg pieces 5 provided on the respective holding fittings 5
b is separated by a predetermined distance. Further, at both ends of the holding piece 5a, the guide pieces 5 are bent at a position corresponding to the engaging claws 3b of the holding frame 3 in a direction away from the base 1.
d is formed.

According to the above-mentioned structure, the holding metal 5 is attached to the base 1.
When the integrated circuit 4 is placed on the base 1 in a state of being connected to the base 1 and then the pressing frame 3 is fitted on the base 1, the tip of the engaging claw 3b comes into contact with the guide piece 5d,
In the state where the holding piece 5a is bent in a direction away from the base 1 and the pressing frame 3 holds the integrated circuit 4 between the holding frame 3 and the base 1,
The engaging claw 3b engages with the lower edge of the holding piece 5a, and the holding frame 3
It is to prevent the float from the base 1. On the other hand, when removing the holding frame 3 from the base 1, the holding piece 5
If a is bent away from the base 1, the holding piece 5a
The engagement state between the engagement claw 3b and the engagement claw 3b can be easily released.

By the way, when mounting the surface mount type socket having the above-mentioned structure on the circuit board 6, for example, a conductive pattern as shown in FIG. 6 is formed on the circuit board 6. As the conductive pattern, the conductive pattern 6a corresponding to the contact spring 2 is used.
Besides, a conductive pattern 6b corresponding to the leg piece 5b of the holding metal fitting 5 is also formed. The leg piece 5 is attached to the conductive pattern 6b.
By soldering b, the fixing strength of the surface mount type socket to the circuit board 6 can be increased. Further, since the conductive pattern 6b is formed independently for each holding metal fitting 5, each conductive pattern 6b can be used for relaying different circuits.

(Embodiment 2) As shown in FIGS. 7 to 9, in this embodiment, the base 1 penetrates in the thickness direction of the base 1 between the positioning projections 1c protruding from the sides of the base 1. The notch 1g is formed. That is, between the positioning protrusions 1c formed side by side, the end surface of the base 1 is substantially aligned with the surface of the positioning protrusion 1c facing the integrated circuit 4.

By providing the notch 1g as described above, the integrated circuit 4 can be easily installed on the base 1. That is, in the integrated circuit 1 such as a thin SOP, since the height is small and small, it is difficult to handle with a finger, and it is common to use tweezers. Therefore, the notch 1g is provided between the positioning protrusions 1c. By this notch 1
g functions as a relief for the tweezers. As a result, if the sides of the integrated circuit 4 where the leads 4a do not project are grasped with tweezers, the integrated circuit 4 can be easily attached to and detached from the base 1, and the alignment is also facilitated. Of. Also, lead 4
Since the side of a that is not protruding is grasped with tweezers, there is no possibility of deforming the lead 4a. Other configurations are similar to those of the first embodiment.

(Embodiment 3) In the present embodiment, as shown in FIGS. 10 to 12, instead of providing the guide side 5d on the holding piece 5a, both ends of the holding piece 5a are opposed to the upper edge of the holding piece 5a. The notch 5e is formed.
The notch portion 5e is formed so that the engaging claw 3b of the holding frame 3 can be temporarily placed. By engaging the engaging claw 3b and the notch portion 5e, the base 1 and the holding frame 3 are formed. It will be possible to align with. That is,
If there is no means for determining the position of the holding frame 3 with respect to the base 1 before fixing the holding frame 3 to the base 1, a force that laterally shifts from the holding frame 3 may act on the integrated circuit 4. When such a force is applied, the lead 4a may be deformed or the lead 4a and the contact spring 2 may not properly correspond to each other. However, as described above, after the pressing frame 3 is temporarily placed on the holding metal fitting 5, If the integrated circuit 4 is pressed against the base 1 as it is, a force for laterally shifting the integrated circuit 4 does not act, and the lead 4a can be prevented from being deformed. Other configurations are similar to those of the first embodiment.

[0019]

As described above, according to the present invention, the terminal piece of the contact spring is bent stepwise, and the press-fitting protrusions are provided on both side surfaces of the fixing piece portion of the terminal piece which is fixed to the base. The width of the bridging piece is set to be narrower than the distance between the tips of both press-fitting protrusions, and the width of the press-fitting fixed piece and bridging piece is set to the base. Since the press-fitting groove having the different first groove portion and second groove portion is formed, the contact spring is press-fitted into the base at two locations, and there is an effect that high fixing strength can be obtained. As a result, the press-fitting groove can be formed in the base so as to be open to the side facing the pressing frame and the side surface, and the thickness of the base can be reduced by opening the side facing the pressing frame. It has the advantage that it can be made smaller.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts showing a first embodiment.

FIG. 2 is an exploded perspective view showing the first embodiment.

FIG. 3 is a plan view showing the first embodiment.

FIG. 4 is a partially cutaway side view of the first embodiment, in which (a) shows a state before the holding frame is attached and (b) shows a state after the holding frame is attached.

FIG. 5 is a partially cutaway front view showing the first embodiment.

FIG. 6 is a plan view of a circuit board on which the first embodiment is mounted.

FIG. 7 is an exploded perspective view showing a second embodiment.

FIG. 8 is a plan view showing a second embodiment with a holding frame removed.

FIG. 9 is a partially cutaway front view of the second embodiment.

FIG. 10 is an exploded perspective view showing a third embodiment.

FIG. 11 is a plan view showing a third embodiment with a holding frame removed.

FIG. 12 is a partially cutaway side view showing a third embodiment.

FIG. 13 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Contact spring 2a Contact piece 2b Terminal piece 3 Holding frame 4 Integrated circuit 4a Lead 6 Circuit board 11 1st groove part 12 2nd groove part 21 Fixed piece part 22 Bridging piece part 23 Connection piece part 24 Press-fitting protrusion

Claims (1)

Claim: What is claimed is: 1. A rectangular base made of an insulating material on which a thin surface-mounted integrated circuit is mounted, a contact piece that comes into contact with each lead of the integrated circuit, and soldering to a circuit board. A large number of contact springs that are formed in a shape in which one ends of the terminal pieces are integrally connected to each other and that are arranged in a row on the peripheral portion of the base, and the contact pieces formed in a rectangular frame shape along the peripheral portion of the base. In a surface-mounted socket for an integrated circuit, which is fixed in a fixed position with respect to the base while being held on the base, and which holds a lead frame of the integrated circuit between the contact piece and the contact frame, a contact spring terminal is provided. The fixed piece connected to the contact piece, the connection piece soldered to the circuit board, and the fixed piece and the connection piece are substantially parallel to each other, and the connection piece is fixed in the thickness direction of the base. With the bridging piece that connects so that it is located closer to the circuit board than the one piece It is equipped with press-fitting projections on both sides of the fixed piece, the distance between the tips of both press-fitting projections is set to be larger than the width of the bridging piece, and the base is the surface facing the holding frame. It is provided with a large number of press-fitting grooves which are open to the side surface and into which the fixing piece portion and the bridging piece portion are press-fitted, and each press-fitting groove is a portion where the fixing piece portion is press-fitted and between the tips of the two press-fitting protrusions A first groove part having a width narrower than the distance and a second groove part having a width narrower than the width of the bridging piece part into which the bridging piece part is press-fitted,
A surface-mounting socket for an integrated circuit, characterized by being formed side by side in the thickness direction of a base.