JPH0629171U - Multilayer printed wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] Electrical components can be directly mounted on the inner layer side wiring pattern, which enables thinning and miniaturization of the wiring board and eliminates the need for connection between the inner layer side wiring pattern and the front side wiring pattern. To do. [Structure] A concave portion 10 having a required depth is formed on a surface of a multilayer printed wiring board 1 to expose a conductive pattern 3 of a third layer printed wiring board 4c. The electric component 2 is inserted and arranged in the recess 10 and is connected to the conductive pattern 3 exposed in the recess 10 of the third-layer printed wiring board 4c.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a multilayer printed wiring board, and more particularly to a mounting structure of electric parts on a wiring board.

[0002]

[Prior art]

 Mounting of capacitors, transistors, diodes, resistors, ICs, etc. (collectively referred to as electrical components below) on conventional multilayer printed wiring boards is carried out planarly on the component surface (front surface) or solder surface (back surface) of the wiring board. Implementation was common. FIG. 3 is a cross-sectional view of an essential part showing a mounting structure of an electric component in a conventional multilayer printed wiring board, in which 1 is a multilayer printed wiring board and 2 and 2'are electric components mounted on the multilayer printed wiring board 1. . In the multilayer printed wiring board 1, one sided or double sided printed wiring board 4 on which the wiring pattern 3 is formed is positioned and a plurality of sheets (3 to 4 sheets) are provided between the prepregs (glass cloth is coated with a semi-cured adhesive and impregnated). It is manufactured by stacking them via an adhesive or by heating and pressurizing them and integrally joining them. The interconnection of the wiring patterns 3 between each layer or a specific layer is performed on the printed wiring board 4. This is done by forming a conductor by plating on the inner wall or the entire inside of the formed through hole (not shown). In addition, 5 is a solder and 6 is a lead wire.

[0003]

[Problems to be solved by the device]

 However, in the above-mentioned conventional multilayer printed wiring board 1, since the front surface or the back surface is the mounting surface of the electrical components 2 and 2 ′, the entire multilayer printed wiring board 1 is thick only by the thickness of the electrical components 2 and 2 ′. There was a problem of becoming. When connecting the electric components 2, 2'to the pattern 3 of the printed wiring board 4 on the inner layer side, the inner layer side wiring pattern 3 and the front surface (or back surface) side wiring pattern 3 are electrically connected by through holes. There is also a problem that the wiring becomes complicated.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to enable electrical components to be directly mounted on an inner layer side wiring pattern and to reduce the thickness and size of a wiring board. It is an object of the present invention to provide a multi-layered printed wiring board that enables the realization of the same and eliminates the connection between the inner layer side wiring pattern and the front surface (or back surface) side wiring pattern.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a multilayer printed wiring board in which a plurality of printed wiring boards are superposed and integrally joined, and conductive patterns between specific layers are connected to each other. Or, a recess of the required depth is formed on the back surface) to expose the conductive pattern of the printed wiring board of any inner layer in the recess, and the electric component is inserted and arranged in the recess and exposed in the recess. It is directly connected to the conductive pattern.

[0006]

[Action]

 In the present invention, the recess accommodates electrical parts and prevents them from protruding from the surface of the wiring board. The electrical components are directly connected to the conductive pattern of the printed wiring board on the inner layer side exposed in the recess, thereby eliminating the need for interconnection between this conductive pattern and the front side wiring pattern.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view of an essential part showing an embodiment of the multilayer printed wiring board according to the present invention, and FIG. 2 is a plan view of the essential part of the same wiring board. In the figure, the same components as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted. In these figures, this embodiment shows a case where the present invention is applied to a multilayer printed wiring board 1 formed by laminating three printed wiring boards 4 (4a to 4c). A concave portion 10 having a required size reaching the third layer printed wiring board 4c is formed at a predetermined position on the surface of the multilayer printed wiring board 1, and an electric component 2 such as a resistor is housed and arranged in the concave portion 10. It is directly connected to the wiring pattern 3 exposed in the recess 10 of the printed wiring board 4c of the layer. Therefore, in such a configuration, it is not necessary to connect the wiring pattern 3 of the third-layer printed wiring board 4c to the wiring pattern 3 on the surface for the electric component 2 by a through hole, which simplifies the wiring. be able to. The concave portion 10 is not limited to a rectangular shape, but may have various shapes such as a round shape depending on the shape of the electric component 2. On the surface of the multilayer printed wiring board 1, another electric component 2'is mounted, if necessary, above the recess 10 and connected to the wiring pattern 3 on the front surface side. In this case, since the electric component 2 is located in the recess 10, there is an advantage that the mounting height of the electric component 2'can be reduced accordingly. The reference numeral 11 is a small hole for heat dissipation which is formed through the third-layer printed wiring board 4c and communicates with the recess 10, but the small hole 11 is not always necessary.

[0008]

[Effect of device]

 As described above, in the multilayer printed wiring board according to the present invention, the concave portion is formed on the front surface or the rear surface of the wiring board to expose the wiring pattern on the inner layer side in the concave portion, and the electric component is inserted in the concave portion and exposed. Since it is configured to be directly connected to the above wiring pattern, it enables thinning and miniaturization of the wiring board itself and high-density mounting of electric parts, and for electric parts, the surface wiring pattern and inner layer side wiring pattern It is possible to provide it at low cost because it is not necessary to connect to, wiring connection is simple.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a multilayer printed wiring board according to the present invention.

FIG. 2 is a plan view of an essential part of the same multilayer printed wiring board.

FIG. 3 is a cross-sectional view of essential parts showing a conventional example of a multilayer printed wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer printed wiring board 2, 2'electrical component 3 Wiring pattern 4, 4a-4c Printed wiring board 10 Recessed part

Claims (1)

[Scope of utility model registration request] 1. In a multilayer printed wiring board in which a plurality of printed wiring boards are superposed and integrally joined and conductive patterns between specific layers are connected to each other, a required depth is provided on a front surface (or a back surface) of the multilayer printed wiring board. To expose the conductive pattern of the printed wiring board of any inner layer in the recess,
A multilayer printed wiring board, characterized in that an electric component is inserted and arranged in the recess and directly connected to a conductive pattern exposed in the recess.