Electronic circuit unit

Abstract

The invention provides a thin and inexpensive electronic circuit unit with reliable reflow solder. In the surface-mounted electronic circuit unit, a circuit board 11 is attached so that a conductive pattern 15 is outside. Electric components 13 positioned inside a cover 1 are electrically shielded by the cover 1 and the conductive pattern 15. During reflow soldering since a hot air passes through an opening 6 of the bottom wall 2 and the tip of the leg 5 is soldered to a wiring pattern 12, the height of the cover can be greatly reduced in comparison with a conventional one, and thus, the circuit unit is made thin. In soldering the cover, the solder for electric components is not melted, and consequently, a reliable reflow solder is obtained.

Description

technical field [0001] The present invention relates to an electronic circuit unit suitable for use in a transmitting and receiving unit used in a mobile phone and the like. Background technique [0002] The structure of the existing electronic circuit unit is described according to FIG. 6 . The box-shaped frame body 51 formed by bending a metal plate has a square bottom wall 52 and four side walls 53 bent upward from the four sides of the bottom wall 52. , a plurality of mounting feet 54 protruding downward from the lower end of the opposite side wall 53 , a foot portion 55 protruding into the frame body 51 bent from the cutout of the bottom wall 52 , and a through hole 56 provided on the bottom wall 52 , The upper side of the side wall 53 becomes an open part. [0003] A circuit board 57 made of a printed circuit board is provided with a wiring pattern 58 on one side 57a as its upper surface, on which IC elements, resistors, capacitors and other electrical components 59 a...

AI Technical Summary

Problems solved by technology

[0014] Usually, the melting temperature of the solder in the first soldering process is set higher than the solder melting temperature in the second soldering process, but when the second soldering process is performed, the hot air directly touches the solder for the electric component 59 in a solidified state, thereby cause the solder to melt

[0015] In the conventional electronic circuit unit, since the circuit board 57 on which the electrical components 59 are mounted is shielded by the box-shaped frame 51 and the cover 61, there is a problem that it becomes larger in the vertical direction.

[0016] In addition, the cover 61 is required in addition to the frame body 51, and there is a problem that the cost becomes high.

[0017] Moreover, when performing the second soldering process, the hot air directly touches the solder for the electric component 59 in a solidified state, causing the solder to melt.

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