JPH01316961A - Printed wiring board mounted with ic socket - Google Patents

Abstract

PURPOSE:To enlarge the wiring region for wires on the rear side of a printed wiring board and to provide a room large enough to facilitate the laying of wires by a method wherein second group lead pins are connected through the intermediary of pads connected to wires on the top side of the printed wiring board and first group lead pins are soldered to through-holes and lands. CONSTITUTION:First group lead pins 18 for an IC socket 16 are inserted into their corresponding through-holes 12 in a printed wiring board 11. Second group lead pins 19 are so guided as to abut against their corresponding pads 15. The lead pins 18, lands 13, and tubular conductors 14 are soldered together for the installation of the lead pins 18 in the through-holes 12. The lead pins 18 are connected to rear side wires 21 on the printed wiring board 11. The lead pins 19 and pads 15 are soldered to each other, when unoccupied space in openings 17 are utilized. The lead pins 19 are connected to wires 22 on the top side of the printed wiring board 11. This enables the number of lands 13 to be reduced by half. This design ensures a sufficiently large room for laying wires.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed wiring board on which an IC socket is mounted, which is effective for reducing the lead pitch of an IC socket and increasing the number of pins.

[Prior art] In conventional IC socket mounting technology, multiple lead pins arranged on an IC socket are inserted into through holes drilled at matching positions on a printed wiring board, and then soldered. The lead pin is fixed to the board. The through-holes provided in the printed wiring board are processed by drilling and then through-hole processing, and then lands are provided at the openings of the holes on the front and back surfaces of the board. Then, the lead pins are inserted into the through holes and soldered at the lands, thereby electrically connecting the lead pins to the wiring patterns formed on the front and back surfaces of the substrate.

FIG. 4 is a back view of a conventional printed wiring board 51. The printed wiring board 51 is provided with through holes 52 arranged in two rows. The through holes 52 are arranged at equal intervals in each row, and the through holes 52 in one row and the through holes 52 in the other row are located at opposite positions in a direction perpendicular to the arrangement direction. It is set in. Furthermore, each through hole 52 has a land 53 at the periphery of both openings on the front and back surfaces of the substrate, respectively.

Then, on the back side of the printed wiring board 51, the back side wiring 54 belongs to a back side land 53 of the through hole 52 belonging to one column.
The column is connected to the column and extends in the direction intersecting the column. Further, on the surface of the printed wiring board 51, a surface-side wiring 55 is connected to a surface-side land 53 of a through hole 52 belonging to the other column, and extends in a direction intersecting that column. In this case, in the area between the rows of through holes 52, each backside wiring 54 and each frontside wiring 55 are connected to lands (others) in other rows that are opposite to the lands (own lands) 53 to which they are connected. It is bent in the vicinity of the land 53 so as not to contact it.

[Problems to be Solved by the Invention] However, in the conventional IC socket mounting board described above, the lead bins of the IC socket all pass through the through hole 52, and selectively connect the front side wiring 55 or the back side wiring 54. It is connected to the. Therefore, areas for forming lands are required on both the front and back sides of the printed wiring board. Therefore, in conventional printed wiring boards, the area in which wiring patterns can be formed is reduced, and as the IC lead pitch is reduced and the number of pins increases, there is no room for routing the wiring patterns, and the wiring patterns become complicated. .

The present invention has been made in view of such problems, and includes:
The area where the wiring pattern can be formed can be made wider and the wiring pattern can be routed with more leeway.Therefore, an IC socket can be mounted that can sufficiently cope with the increase in the number of pins and the number of wiring patterns in the IC socket. The purpose of the present invention is to provide a printed wiring board with improved performance.

[Means for Solving the Problems] A printed wiring board on which an IC socket according to the present invention is mounted has a pad connected to a wiring pattern provided on its mounting surface and a pad connected to a wiring pattern provided on its back surface. The IC socket has a through hole that penetrates through the IC socket in its thickness direction, and a land provided at the opening of the through hole.
A group of lead bins are soldered to the pads on the mounting surface, and a second group of lead bins of the IC socket are inserted into the through holes and soldered to the lands on the back surface.

[Function] In the present invention, a pad is connected to the wiring pattern provided on the IC socket mounting surface of the printed wiring board, and a through hole passing through the board in the thickness direction is provided in the wiring pattern provided on the back surface. is connected. Then, the first group of lead bins with short IC sockets are soldered to the pads on the board mounting surface, and the second group of lead bins with long IC sockets are inserted into the through holes and soldered to the lands on the back surface of the board. As a result, the first group of lead bins are connected to the wiring pattern on the board mounting surface via the pads, and the second group of lead bins are connected to the wiring pattern on the back surface of the board via the lands and through holes. Therefore, the number of through holes is reduced by half, for example, and the number of lands is significantly reduced, especially on the back surface of the substrate. Therefore, the wiring area on the back surface becomes wider, and the routing of the wiring pattern becomes extremely easy.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the accompanying drawings.

FIGS. 1(a) and 1(b) are a longitudinal sectional view and a back view of the printed wiring board, respectively, showing a first embodiment of the present invention.

At the bottom of the IC socket 16 are a first group of long lead bins 18 that are long enough to penetrate the printed wiring board 11, and a second group of short lead bins 19 that reach only the surface of the printed wiring board 11. They are arranged vertically and alternately. The first and second groups of lead bins 18.
Two rows of lead bins consisting of 19 are provided as shown in FIG. 1(b). Note that openings 17 are provided at the bottom of both sides of the IC socket 16, and when the IC socket 16 is mounted on the printed wiring board 11, which will be described later, a lead bin is inserted from the side of the IC socket through the openings 17. 18.19 can be visually recognized and soldering can be done.

The printed wiring board 11 is connected to the long first part of the IC socket 16.
A plurality of through holes 12 penetrate through the substrate in the thickness direction at positions that match the arrangement positions of the lead pins 18 of the group, and the substrate 11
It has a plurality of circular pads 15 arranged at positions matching the arrangement positions of the second group of glued pins 19 of the IC socket 16 on the mounting surface (front surface) of the IC socket. The through hole 12 is
After drilling holes in the printed wiring board 11, through-hole processing is performed, and furthermore, lands 13 are formed at the openings of the holes on the front and back surfaces of the board, respectively. A cylindrical conductor portion 14 is formed between both lands 13 on the front and back surfaces of the substrate.

The lead pins 18 of the first group are soldered to the through holes 12 and the lands 13, and one glued pin of the second group is soldered to the pad 15.

In the printed wiring board 11 described above, the through holes 12 are arranged in two rows. That is, the through holes 12 are arranged at predetermined intervals in each row, and the through holes 12 in one row and the through holes 12 in the other row face each other in a direction perpendicular to the direction in which they are arranged. It's located like that. On the mounting surface of the printed wiring board 11, a pad 15 is formed approximately in the center between the drilled positions 1 of the through holes 12 on each row of the through holes 12.
and pads 15 are arranged alternately. Further, on the back surface of the printed wiring board 11, back side wiring 21 connected to the own land 13 is formed extending in a direction intersecting the rows formed by the through holes 12. In this case, in the region between the rows of through holes 12, each backside wiring 21 is connected to its own land 13.
It is bent in the vicinity of the other land 13 opposite to the other land 13 so as not to contact therewith.

On the other hand, on the surface of the printed wiring board 11, the surface side wiring 2
2 are provided in substantially the same pattern as the backside wiring 21 described above. That is, the front side wiring 22 connected to the own pad 15 is bent in the area between the rows of pads 15 in the vicinity so as not to contact the other pad 15 facing the own pad 15, and the through hole 12 is It is formed to extend in a direction intersecting the rows.

The IC socket 16 configured in this manner is mounted on the printed wiring board 11 in the following manner.

First, the first group of glue pins 18 of the IC socket 16 are inserted into the corresponding through holes 12 of the printed wiring board 11, and the second group of lead pins 19 are brought into contact with the corresponding pads 15. Subsequently, in this state, the first group of lead pins 18, both land portions 13, and the cylindrical conductor portion 14 are soldered to attach the first group of lead pins 18 to the through holes 12. Thereby, the first group of lead pins 18 and the back side wiring 21 of the printed wiring board 11 are electrically connected.

Similarly, the second group of glue pins 19 and the pads 15 are soldered using the space of the opening 17, whereby the second group of lead pins 19 and the printed wiring board 1 are soldered.
1 is electrically connected to the wiring 22 on the front surface side.

In this way, according to the device of this embodiment, the IC socket 16
In the printed wiring board 11, one of the plurality of second group lead pins electrically connected to the wiring 22 on the front side of the board is shortened, and the plurality of second group lead pins 19 are shortened in the printed wiring board 11. The pads 15 are provided at positions that correspond to the respective arrangement positions, and one of the lead pins of the second group and the pad 15 are soldered. Therefore, on the back side opposite to the IC socket mounting surface (front surface),
The number of lands 13 can be reduced by half compared to the conventional printed wiring board 51 shown in FIG. Therefore, it is possible to have a wide wiring area on the back surface of the printed wiring board 11, thereby providing sufficient margin for routing the wiring.

FIG. 2 is a back view showing a printed wiring board 23 according to a second embodiment of the present invention.

As shown in FIG. 2, the two rows of through holes 24 are arranged in a staggered pattern, and each through hole 24 has a land 25 at the hole opening on the front and back surfaces of the substrate.
In Figure 2, only the land 25 on the back side is shown)
. Then, on the surface of the printed wiring board 23, the through holes 2
4, circular pads 26 are provided approximately in the middle between the arrangement values 1 of the through holes 24 so as to alternate with the through holes 24.
is provided. Therefore, on the front surface side of the printed wiring board 11, the pad 26 is formed at the through hole 24.
As in the case of , it forms a staggered pattern.

Further, each back side wiring 27 is connected to its own land 25,
It extends linearly in a direction intersecting the rows of through holes 24. On the other hand, each surface-side wiring 28 is connected to its own pad 26, but is bent in the vicinity of the other land 25 facing the own pad 26 in the area between the rows of through holes 24 so as not to contact the other land 25, and , extending in a direction intersecting the rows of pads 26.

In this way, also in the case of the printed wiring board 23 shown in FIG. 2, the land 2 is
A conventional printed wiring board 51 whose number of pieces is shown in FIG.
can be reduced by half. Therefore, the wiring possible area on the back surface of the substrate can be widened, and sufficient margin can be provided for routing the wiring.

FIG. 3 is a perspective view showing a third embodiment of the present invention.

Components that are the same as those in FIGS. 1(a) and 1(b) are designated by the same reference numerals and their descriptions will be omitted.

In the IC socket 36 of this embodiment, the lower part of the second lead pin 39 is bent toward the outside of the IC socket 36, forming an L-shape. Also, in response to this,
On the IC socket mounting surface of the printed wiring board 31,
The pads 35 provided at positions aligned with the positions of the second lead pins 39 have a shape extending along the direction of extension of the front-side wiring 22, for example, a rectangular shape or an elliptical shape. ing.

The IC socket 36 configured in this manner is mounted on the printed wiring board 31 by bringing the bent lower portions of the three second lead pins into contact with the pads 35, and in this state, both are soldered and fixed. Therefore, according to this embodiment, since the second lead pin 39 electrically connected to the predetermined wiring 22 on the IC socket mounting surface has a large part to be soldered, the soldering work can be easily performed. I can do it.

[Effects of the Invention] As explained above, according to the present invention, the front side wiring provided on the IC socket mounting surface of the printed wiring board is connected to the IC socket via the pad connected to the front side wiring. The second group of lead pins are connected, and the back side wiring provided on the back side of the printed wiring board has a length sufficient to pass through the board of the IC socket into the plurality of through holes drilled in the board. A plurality of lead pins of the first group are inserted and soldered to the through holes and lands, respectively. For this reason, the number of lands in the through holes can be significantly reduced on the back side of the printed wiring board, so that a wide wiring area can be provided on the back side of the board. Therefore, it is possible to provide sufficient margin for routing the wiring, so that it is possible to sufficiently cope with an increase in the number of pins of an IC and an increase in the number of wiring patterns, thereby effectively avoiding the complexity of the wiring pattern.

[Brief explanation of the drawing]

'Figures 1(a) and (b) are a vertical cross-sectional view and a rear view of a printed wiring board showing a first embodiment of the present invention, respectively, and Figure 2 is a printed wiring diagram showing a second embodiment of the present invention. FIG. 3 is a rear view of the substrate, and FIG. 3 is a perspective view showing the third embodiment of the present invention.
The figure is a back view of a conventional printed wiring board. 11.23,31,51, printed wiring board, 12.
24.52. Through hole, 1B, 25.53; land, 15
, 26, 35. Pad, 16, 36; IC socket, 1
7; Opening, 18; First glued pin, 19, 39; Second lead pin, 21° 27.54; Back side wiring, 22
, 28, 55; surface side wiring

Claims (1)

[Claims] (1) A pad connected to a wiring pattern provided on the mounting surface, a through hole connected to the wiring pattern provided on the back surface and penetrating in the thickness direction, and a pad provided at the opening of the through hole. and the first land of the IC socket.
An IC socket is mounted, wherein a group of lead pins are soldered to the pads on the mounting surface, and a second group of lead pins of the IC socket are inserted into the through holes and soldered to the lands on the back surface. printed wiring board.