JPH03198398A - Printed-wiring board - Google Patents

Abstract

PURPOSE:To make it possible to solder lead pins on pads easily and reliably by a method wherein the form of each pad of the pad rows, which correspond to lead pin rows on the short sides of a package element, on a printed-wiring board is formed longer in its width direction. CONSTITUTION:In a glass-cloth epoxy resin printed wiring board 2 formed with pads 1 to correspond to lead pin rows and lead pin columns on a rectangular package element 3 having lead pins 3a and 3b on its individual sides, the width of each pad of the pad rows, which correspond to the lead pin 3b rows on the short sides of the element 3, among pad 1 rows and pad 1 columns, is formed wider than that of each pad of the other pad columns in the width direction 1b. The element 3 is subjected to soldering treatment on this wiring board 2 and the lead pins 3a and 3b are soldered on the pads 1 to correspond to the individual lead pins on one surface of the board 2. As a result, the uniform and good connection of the element 3 with the board 2 is obtained as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a printed wiring board, and particularly to a printed wiring board suitable for surface mounting of rectangular packaged elements.

(Prior Art) In electronic equipment, printed wiring boards with the required printed wiring paths are used for the purpose of compacting or integrating circuit mechanisms, and the required circuit elements (electronic components) are printed on the surface of the printed wiring board. ) is widely known to be mounted and mounted and used as a mounted circuit device. By the way, on the surface of the printed wiring board for surface mounting, there is a board for electrically connecting the electronic components to be mounted/mounted, for example, lead pins (forming lead pin rows) on two opposing sides or four opposing sides. , pads (forming pad rows) corresponding to these lead pins are formed. However, as shown in plan in FIG. 2, the pads are generally shaped into various shapes for each corresponding package element or regardless of the type of electronic components to be mounted/mounted, without considering directionality. It is shaped. That is, the length direction 1a and the width direction 1b of the pad 1 are made constant, or the length direction 1a and the width direction! b is the same. In addition, in the figure, 2 indicates a printed wiring board.

(Problems to be Solved by the Invention) However, in the case of a printed wiring board in which pads are formed as described above, the following disadvantages are recognized. That is,
If the circuit element (electronic component) to be mounted/mounted on the printed wiring board is a rectangular flat package element, for example, during reflow soldering, the package element 3 may warp, as shown from the side in Figure 3. There is no problem with the lead pins 3a on the long sides of the element 3, but the lead pins 3b on the short sides often appear floating, resulting in poor soldering. In other words, the lead pins 3a extending along the long sides of the rectangular package element 3 can perform the required soldering without being relatively affected by the warping phenomenon of the package element 3; The lead pins 3b extending in the lead pins 3b are generally opened laterally, making it difficult for them to come into contact with one surface of a predetermined pad, so that highly reliable half-III attachment is often not achieved. Ru.

The present invention has been made in response to the above-mentioned circumstances, and an object of the present invention is to provide a printed wiring board to which lead pins extending on each side of a rectangular flat package element can be soldered neatly and reliably.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a printed wiring board in which pad rows are formed corresponding to lead pin rows of a rectangular package element having lead pins on each side. It is characterized in that each pad of the pad row corresponding to the lead pin row on the short side is formed to be elongated in the width direction.

(Function) In the printed wiring board according to the present invention, in the pad row to which the lead pins extending on each side of the rectangular package element mounted/mounted on the printed wiring board are soldered,
The width of each pad on the short side is relatively wide. Therefore, even if the rectangular package element to be mounted/mounted is warped and the lead pins at both ends of the short side are opened outward, they can make sufficient contact with each other, making it possible to reliably achieve the required soldering or electrical connection. .

(Example) The present invention will be described in detail below with reference to FIG.

FIG. 1 is a plan view showing an example of the configuration of a printed wiring board according to the present invention, and 2 indicates pads 1 (forming pad rows) corresponding to lead pin rows of a rectangular package element 3 having lead pins 3as and 3b on each side. This is a glass cloth-epoxy resin printed wiring board on which a lead pin 3b row on the short side is formed, and the width direction 1a of each pad in the pad row corresponding to the lead pin 3b row on the short side of the pad row is It is characterized by being wider (elongated) than the width of the pad. For example, in the case of a printed wiring board for a memory card, each pad 1 in the pad row corresponding to the lead pin 3b row on the short side of the rectangular package element 3 has a length direction 1a of 0.91- 1 width direction 1b is 0.9 mm, and each pad 1 in the pad row corresponding to the lead pin 3a row on the long side of the rectangular package element 3 is 0.9 gv in the length direction 1a and 0.8-1 in the width direction 1b.
These are the settings for each.

The resin-molded rectangular package element 3 is soldered to the memory card printed wiring board configured as described above using the usual solder reflow method, and each lead pin 3a, 3b is attached to one side of the printed wiring board. When the corresponding pads 1 were soldered, uniform and good soldering or electrical connection could be achieved overall. In other words, for each pad of the printed wiring board for the memory card, the lead pins on each side of the resin-molded rectangular package element 3 exhibit good soldering properties and electrical properties in the normal solder reflow method. A reliable connection was made both mechanically and mechanically.

In addition, although the printed wiring board for memory cards was exemplified above, good soldering was similarly observed in the configurations of other mounted circuits (devices). In addition, the size of each pad corresponding to the lead pins on each side of the rectangular package element 3 is appropriately set depending on the number and pitch of lead pins of the rectangular package element 3 to be mounted/mounted, but in any case, the pads on the short side The width of each pad forming the row needs to be set wider than the width of each pad forming the long side pad row.

[Effects of the Invention] As explained above, in the printed wiring board according to the present invention, there are pad rows to which lead pins extending on each side of the rectangular package element mounted/mounted on the surface of the printed wiring board are soldered. The width of each pad on the middle and short sides was selected and set to be relatively wide. Therefore, even if the rectangular package element to be mounted/mounted is warped and the lead pins at both ends of the short side are opened outward, the required half-fi attachment or electrical connection can be achieved reliably because the lead pins at both ends of the short side can be fully contacted. .

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of the configuration of a printed wiring board according to the present invention, Fig. 2 is a plan view showing the configuration of a conventional printed wiring board, and Fig. 3 is a plan view showing an example of the configuration of a conventional printed wiring board. - It is a side view schematically showing the state when mounted. 1...Pad la...Length direction ib...Pad width direction 2...Printed wiring board 3...Package element

Claims (1)

[Scope of Claims] In a printed wiring board in which pad rows are formed corresponding to lead pin rows of a rectangular package element having lead pins on each side, each of the pad rows corresponds to a lead pin row on a short side of the pad rows. A printed wiring board characterized in that a pad is formed to be long in the width direction.