JPH06310890A - Circuit unit - Google Patents

Abstract

PURPOSE:To stably solder a shield case and a printed board, and obtain excellent shield case effect. CONSTITUTION:In a shield case 11, cut-and-raised segments 13 are arranged by opening one side bottom surface of a rectangular parallelopiped with narrow width parts 13c or thin-wall parts on side surfaces of the rectangular parallelopiped. The narrow width part 13c has a narrow part in the width direction. The thin-wall part has a thin part in the thickness direction. A printed wiring board 12 is arranged in the shield case 11 with an arbitrary gap, and has lands 15 corresponding with the cut-and-raised segments 13, which are bent and connected inside the shield case 11. The lands 15 of the printed board 12 are soldered to the cut-and-raised segments 13 of the shield case 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit unit used for a tuner or the like of a television receiver.

[0002]

2. Description of the Related Art As a circuit unit used for a tuner of a television receiver, a printed circuit board on which a predetermined electric circuit is formed is housed inside a shield case.

Below, a conventional circuit unit is shown in FIG.
This will be described with reference to FIG. In the figure, reference numeral 1 denotes a shield case in which one bottom surface of a rectangular parallelepiped is opened, and protects electronic components mounted on the internal printed circuit board 2 and the like from external impact and electromagnetic waves. Reference numeral 2 denotes a printed circuit board which is disposed in the shield case 1 with an arbitrary gap, and electronic parts are mounted so as to form a predetermined electric circuit. Denoted at 3 is a cut-and-raised piece provided by punching the side surface of the shield case 1 into a predetermined shape, for holding the printed circuit board in the shield case 1. Reference numeral 4 denotes an opening formed by providing the cut-and-raised piece 3. Reference numeral 5 denotes a land provided on the outer peripheral portion of the printed circuit board 2 and is provided corresponding to the cut-and-raised piece 3. Reference numeral 6 is a solder for joining the cut-and-raised piece 3 and the land 5 together.

In the above structure, the printed circuit board 2 is arranged inside the shield case 1, and the cut-and-raised piece 3 is made to correspond to the cut-and-raised piece 3 and the land 5.
The finished product is obtained by soldering the land 5 to the land 5 by the dip soldering method.

Generally, a plated iron plate is used for the shield case and a glass epoxy resin is used for the printed circuit board.

[0006]

However, in the above-mentioned conventional configuration, when the ambient temperature of the soldered part changes due to the environmental temperature change, the temperature change when the circuit is turned off due to the heat generation of the electronic parts when the circuit is energized, and the like. Due to the difference in thermal expansion coefficient between the printed circuit board and the shield case, the land and the soldered portion are displaced from each other, and stress concentration occurs in the soldered portion. further,
When this temperature change is repeatedly generated, solder cracks may occur in the soldered portion.

The present invention solves the above-mentioned conventional problems and provides a shield case in which solder cracks do not occur even when temperature changes repeatedly occur.

[0008]

In order to achieve the above object, a circuit unit of the present invention has a rectangular parallelepiped whose one bottom surface is open and has a narrowed portion on a side surface of the rectangular parallelepiped which is narrowed in the width direction and has a thickness direction. A shield case provided with a cut-and-raised piece having a thin portion of which is thinned, and a printed circuit board disposed in the shield case and provided with a land corresponding to the cut-and-raised piece of the shield case on the outer peripheral portion. The cut-and-raised piece of the shield case is bent and connected to the inside of the shield case, and the cut-and-raised piece of the shield case and the land of the printed circuit board are soldered.

[0009]

With this configuration, even when the atmosphere temperature of the soldered portion changes, stress concentration in the soldered portion caused by the deviation between the land and the soldered portion can be prevented by the stress deformation of the narrow portion or the thin portion, and the solder crack can be prevented. To prevent the occurrence of.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIGS. 1 to 3, reference numeral 11 denotes a shield case in which one bottom surface of a rectangular parallelepiped is opened, and an external printed board 12 is provided with shock and electromagnetic waves.
Protects electronic components etc. Shield case 1
Printed circuit board 12 provided with an arbitrary gap in 1
The electronic components are mounted so as to form a predetermined electric circuit. Reference numeral 13 denotes a cut-and-raised piece provided by punching a side surface of the shield case 1 into a predetermined shape. The cut-and-raised piece 13 includes a land connecting portion 13a, a thin portion 13b,
It has a narrow portion 13c. Reference numeral 14 denotes an opening formed by providing the cut-and-raised piece 13 on the shield case 1. Here, the thin portion 13b in which a part of the cut-and-raised piece 13 is thinned in the thickness direction facilitates bending of the land connection portion 13a and relaxes stress concentration generated in the soldered portion. The narrow width portion 13c obtained by narrowing a part of the cut-and-raised piece 13 in the width direction relieves stress concentration generated in the soldered portion.

Reference numeral 15 denotes a land provided on the outer peripheral portion of the printed circuit board 12, which is provided corresponding to the cut-and-raised piece 13. Reference numeral 16 is a solder for joining the cut-and-raised piece 13 and the land 15 together.

In the above structure, the cut-and-raised piece 1 is formed.
3 and the land 15 in correspondence with each other, the shield case 1
1, the printed circuit board 12 is disposed, and the cut-and-raised piece 13 is bent and brought into contact with the inside of the shield case 11, and then the cut-and-raised piece 13 and the land 15 are arranged.
And dip soldering.

With this structure, even if the atmosphere temperature of the solder 16 changes and the land 15 and the solder 16 are misaligned, the stress concentration of the solder 16 is reduced by the thin portion 13b.
Further, it is possible to prevent the narrow width portion 13c from being deformed by stress, and it is possible to prevent a solder rack from being generated.

In the present embodiment, the cut-and-raised piece is provided with both the narrow width portion and the thin-walled portion, but the same effect can be obtained when the cut-and-raised piece is provided with either the narrow width portion or the thin-walled portion. .

(Embodiment 2) FIGS. 4 to 6 show another embodiment of the present invention. In this embodiment, the cut-and-raised piece 13 is inserted and fitted into the outer peripheral portion of the printed circuit board 12. The holes 17 are provided.

In the above structure, the cut-and-raised piece 1
3 and the land 15 in correspondence with each other, the shield case 1
1, the printed circuit board 12 is disposed, the cut-and-raised piece 13 is bent into the shield case 11, and the cut-and-raised piece 13 and the cut-and-raised piece 13 are inserted into the through hole 17 as shown in FIG. Dip soldering is performed on the land 15.

With this configuration, in the present embodiment, the cut-and-raised piece is provided with the narrow width portion, but the same effect can be obtained even when the cut-and-raised piece is provided with the thin portion 13b as shown in FIGS. can get.

[0019]

As described above, according to the present invention, the cut-and-raised piece of the shield case is bent inside the shield case, and the cut-and-raised piece of the shield case and the land of the printed circuit board are soldered. The circuit unit does not have the risk of solder cracking even when it is used for a long period of time under severe temperature changes, improving the reliability of soldering quality and realizing an excellent circuit unit that enables high-density mounting. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of a circuit unit according to an embodiment of the present invention.

[Figure 2] Enlarged view

FIG. 3 is an enlarged perspective view of the same.

FIG. 4 is a perspective view of a circuit unit according to another embodiment of the present invention.

FIG. 5 is a plan view of the main part of the unit

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a plan view of a circuit unit according to another embodiment of the present invention.

8 is a sectional view taken along line BB in FIG.

FIG. 9 is a perspective view of a circuit unit in a conventional example.

FIG. 10 is a detailed diagram of the same as above.

[Explanation of symbols]

 11 Shield Case 12 Printed Circuit Board 13 Cut-and-raised Piece 13a Land Connection Part 13b Thin-walled Part 13c Narrow Width Part 15 Land 16 Solder 17 Through Hole

Claims (2)

[Claims] 1. A shield provided with a cut-and-raised piece having one bottom surface of a rectangular parallelepiped opened and having at least one of a narrow portion narrowed in the width direction and a thin portion thinned in the thickness direction on a side surface of the rectangular parallelepiped. A case and a printed circuit board disposed in the shield case and provided with a land corresponding to the cut-and-raised piece of the shield case on the outer peripheral portion, and the cut-and-raised piece of the shield case inside the shield case. A circuit unit obtained by bending and soldering the cut and raised piece of the shield case and the land of the printed circuit board. 2. The circuit unit according to claim 1, wherein a through hole into which the cut-and-raised piece is inserted is provided on the outer peripheral portion of the printed circuit board.