JPH0553268U - Multilayer printed circuit board unit - Google Patents

Abstract

(57) [Summary] [Structure] A step is provided on the board edge of the multilayer printed board so that part of one of the conductive layers except the first layer is exposed from the board surface. Mount the mounting components across. [Effect] When mounting components on the board edge of the printed circuit board,
Since the conductive layer can be mounted over two layers, it is not necessary to pass the wiring from the pad on the board end side away from the pad on the center side of the substrate adjacent to the pad, so that the mounting with a narrow pitch becomes possible.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a multilayer printed circuit board unit on which mounting components are mounted.

[0002]

[Prior Art]

 Fig. 5 is a perspective view of a printed circuit board in the case where a multi-pin surface mount component (for example, a connector of a memory card) is mounted on the board end portion of the conventional printed circuit board, and its wiring pattern is shown in Fig. 6 7 and 8 are cross-sectional views taken along the line AA ′ of FIG. 6 in which the mounted components are connected.

The multilayer printed circuit board is composed of, for example, four conductive layers 13, a curable insulating layer 12 that insulates each conductive layer, and a solder list 11. The conductive layer 13 is provided with wiring made of copper. Wirings 3a for connecting the pads to each other are formed on the first conductive layer 13 from the surface of the printed board. The solder list 11 forms an insulating film on the surface of the printed board 1. When the solder list is applied, a predetermined part of the wiring 3 is left unpainted to form pads 2a and 2b which are areas to be connected to the leads of the mounted components. The pad 2a is arranged on the board end side of the multilayer printed board, and the pad 2b is arranged inside the pad 2a. Reference numeral 12 is a curable insulating layer made of glass epoxy or the like. The mounting component 4a is a component for surface mounting, and the mounting component 4b is a component composed of four rows of leads sandwiching the board. The mounted components 4a and 4b are soldered to the pads 2a and 2b by leads.

Here, when the multi-pin mounting component is mounted at a position other than the plate edge of the printed board, it is not necessary to pass the wiring 3 between the pads 2 as shown in FIG. In the case of mounting, the wiring 3 has to pass through the pad 2a between the adjacent pads 2b as shown in FIG. Therefore, there is a limit in narrowing the pitch width C. Moreover, even if a mounted component that is connected by a through hole is used, the land portion of the through hole land cannot be formed at the plate edge of the printed board.

[0005]

[Problems to be solved by the device]

 When mounting components on the board edge of the printed circuit board, the wiring pattern is passed through, so there must be a sufficient space between adjacent pads, and narrow pitch mounting was not possible. In addition, the mounting components with a wide lead pitch for exclusive use on the plate edge must be manufactured according to special specifications, which increases the manufacturing cost. Therefore, it has been desired that the board can be mounted at a narrow pitch with the mounting component having a normal pitch width (narrow pitch) as it is. In view of the above points, an object of the present invention is to provide a multilayer printed circuit board unit in which mounting components are mounted on a plate edge of the mounting substrate with a narrow pitch.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, a multi-layer printed circuit board unit of the present invention comprises a multi-layer printed circuit board having a first conductive layer and a second conductive layer on which wiring is provided, and the first multi-layer printed circuit board of the multi-layer printed circuit board. And a mounting component that is surface-mounted across the second conductive layer.

Further, in the above-mentioned multilayer printed circuit board unit, a first step surface provided with a first pad for connecting the first conductive layer and a part of a plurality of leads of the mounting component, A second pad provided with a step on the printed circuit board, and a second pad for connecting the second conductive layer different from the first step surface and the remaining part or all of the plurality of leads of the mounting component. A printed board having a step surface, and a mounting component surface-mounted on the first step surface and the second step surface by the lead are provided.

[0008]

[Action]

 The printed board is composed of two or more conductive layers, and an insulating film is formed between adjacent conductive layers. Wiring is applied to each conductive layer. Two or more conductive layers are partially exposed on the surface of the printed board. The mounted component includes a plurality of leads and is surface-mounted across the exposed portion of the first conductive layer and the exposed portion of the second conductive layer.

Thus, even when mounting components on the board edge of the printed board, two layers of conductive layers can be used, so that wiring from the pad at the board edge can be performed by connecting the pad on the board center side adjacent to the pad. Since it is not necessary to avoid it, narrow pitch mounting is possible.

Further, a step is provided on the plate edge of the printed board so that a part of one layer of the conductive layer except the first layer is exposed from the surface of the board. If the surface of the substrate is a one-step surface, and the surface provided substantially parallel to the one-step surface is a two-step surface, then a mounting component having a plurality of leads can be mounted over the one-step surface and the two-step surface. In this way, it is easy to provide a step at the plate edge of the printed board, and therefore, narrow pitch mounting can be easily realized.

[0011]

【Example】

 Examples of the present invention will be shown below. Fig. 1 is a perspective view of a printed circuit board in the case of mounting multi-pin surface mounting parts on the board edge part of the printed circuit board, Fig. 2 is its wiring pattern diagram, and Figs. 3 and 4 are the mounting parts connected to the printed circuit board. FIG. 3 is a sectional view taken along the line AA ′ of FIG. 2. The same configurations as those described in the related art will be omitted. A step is provided at the plate edge of the printed board as shown in the figure. The upper step of this step is the substrate surface 5b, and the lower step is the inner layer surface 5a. A pad 2b is provided on the substrate surface 5b, and the pad 2b is integrally formed with the wiring 3a provided on the first conductive layer from the substrate surface 5b. A pad 2a is provided on the inner layer surface 5a, and the pad 2a is integrally formed with a wiring 3b provided on the second conductive layer from the substrate surface 5a.

As a method of producing a printed board having such a step, it is conceivable to use a method of cutting from the outer layer or a step of taping the portion to be the inner layer surface 5a when laminating the multilayer boards in advance and peeling off when completed. However, the creation method is not specified.

By providing a step at the end of the printed board, the wiring 3b passes through the lower layer of the conductive layer having the wiring 3a, so that it is not necessary to pass the wiring 3b between the inner pads 2b as in the conventional example. The width C can be a narrow pitch.

In addition, in order to make it easy to understand in the drawing, there are considerable steps, but in reality, it is about 0. Since there is a difference of only 1 mm to 0.3 mm, standard parts can be used without changing the lead length.

[0015]

[Effect of the device]

 As described above, according to the present invention, since two conductive layers can be used for mounting components on the board edge of the printed board, the wiring from the pad on the board edge is adjacent to the pad. Since it is not necessary to avoid passing through the pads on the center side of the board, narrow pitch mounting is possible.

[Brief description of drawings]

FIG. 1 is a perspective view of the multi-layer printed circuit board unit of the present invention in the vicinity of a plate end of the multi-layer printed circuit board.

FIG. 2 is a view of the vicinity of a plate edge of the multilayer printed board of the multilayer printed board unit according to the present invention as viewed from above.

FIG. 3 is a cross-sectional view of a multilayer printed circuit board unit according to the present invention.

FIG. 4 is a cross-sectional view of a multilayer printed circuit board unit according to the present invention.

FIG. 5 is a perspective view of the vicinity of a plate end of a multilayer printed board of a conventional multilayer printed board unit.

FIG. 6 is a view of the vicinity of the plate edge of the multilayer printed board of the conventional multilayer printed board unit as viewed from above.

FIG. 7 is a cross-sectional view of a conventional multilayer printed circuit board unit.

FIG. 8 is a sectional view of a conventional multilayer printed circuit board unit.

FIG. 9 is a perspective view of a multilayer printed circuit board of a multilayer printed circuit board unit mounted at a position other than the plate edge.

[Explanation of symbols]

 13 conductive layer 12 insulating layer 11 solder list 3, 3a, 3b wiring 2a, 2b pad 4a, 4b mounting component 5b substrate surface 5a inner layer surface

Claims (2)

[Scope of utility model registration request] 1. A multilayer printed circuit board comprising: a first pad connected to a first conductive layer provided with wiring; and a second pad connected to a second conductive layer provided with wiring. And a mounting component including a plurality of leads, wherein at least one lead is stacked and mounted on the first pad of the multilayer printed board, and at least one other lead is stacked and mounted on the second pad. A multi-layer printed circuit board unit characterized by comprising. 2. The multilayer printed circuit board unit according to claim 1, further comprising a first step surface provided with a first pad for connecting the first conductive layer and a part of a plurality of leads of the mounting component. A second step surface provided with a second pad for connecting the second conductive layer and some or all of the rest of the plurality of leads of the mounting component, different from the first step surface due to a step A multilayer printed circuit board unit, comprising: a printed circuit board including: and a mounting component that is surface-mounted by the lead over the first step surface and the second step surface.