JP2006237137A - Electronic circuit unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic circuit unit that ensures the mounting strength of a shield cover, and is miniaturized and thinned. <P>SOLUTION: The electronic circuit unit comprises: a substrate 1 where a circuit component is mounted onto a main surface 1a and a plurality of recessed grooves 2-4 are provided on a side, and a side electrode 5 is provided on the inner wall surface of respective recessed grooves 2-4; and the shield cover 6 that has a top board section 6a for covering the main surface 1a and a leg piece 7 inserted into the recessed grooves 3, 4 for soldering, and is made of a metal plate. The recessed groove 3 provided on the side of the long side of the substrate 1 has a two-stage structure, comprising a deep groove section 3a into which the leg piece 7 is inserted, and a pair of shallow groove sections 3b adjacent to the deep groove section 3a. The deep groove section 3a is a semicircular groove that is deeper than the plate thickness of the leg piece 7, and each shallow groove section 3b connected in the width direction of the deep groove section 3a is a semicircular groove that is shallower than the deep groove section 3a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small electronic circuit unit such as a VCO (Voltage Controlled Oscillator) in which a shield cover is attached so as to cover a main surface of a substrate on which circuit components are mounted, and in particular, by inserting leg pieces of the shield cover. The present invention relates to a shape of a concave groove formed on a side surface of a substrate for soldering.

  A VCO that constitutes a local oscillator in a cellular phone or the like is roughly configured by mounting circuit components such as a varicap diode, a capacitor, and a transistor on the main surface of the substrate, and covering the main surface of the substrate with a shield cover made of a metal plate. This is a small electronic circuit unit. This type of electronic circuit unit has grooves at a plurality of positions on the side surface of the substrate, and side electrodes provided on the inner wall surface of each groove are used as input / output terminals and ground terminals. Of these, the concave groove provided with the side electrode for the ground terminal is a groove for inserting and soldering a leg piece protruding from the shield cover, and is generally a semicircular groove or a semi-long groove. It is formed as a circular wide groove (for example, see Patent Document 1). In this way, the shield cover leg piece is soldered to the ground terminal (side electrode) on the side surface of the board, and the main surface of the board is covered with the top plate portion of the shield cover, thereby ensuring a shielding effect on the circuit components. The shield cover can be attached to the substrate in a state.

In addition, in the manufacturing site of this type of electronic circuit unit, with respect to a large-sized substrate that is divided into regions for a large number of units by lattice-shaped dividing grooves extending vertically and horizontally, a through hole located on the dividing grooves and each region are provided. After forming wiring patterns, electrodes, etc., and further arranging circuit parts and shield covers for each region, the large substrate is cut along the dividing grooves with a dicing blade or the like, so that a large number of electronic circuit units can be obtained. It is designed to be manufactured in bulk. That is, the concave groove is formed by dividing the through hole on the dividing groove into two in the cutting step, and the side electrode is formed in each through hole in advance before the cutting step and the solder is formed. Is filled.
Japanese Patent Laid-Open No. 10-284935 (page 3-4, FIG. 2)

  By the way, in recent years, electronic circuit units such as VCOs have been promoted to be smaller and thinner, so that the groove formed on the side surface of the substrate has been reduced, and accordingly, the amount of solder filled in the groove has been reduced. Thus, there is a problem that the soldering strength to the leg pieces of the shield cover tends to be insufficient. That is, if a sufficient amount of solder is not filled in the concave groove into which the leg piece is inserted, the strength of the shield cover will be weakened, and the shield cover will come off the board when an impact is applied by a drop test or the like. Therefore, the manufacturing yield and reliability of the electronic circuit unit are greatly reduced.

  Therefore, in order to secure the mounting strength of the shield cover, it is conceivable that the concave groove into which the leg piece is inserted is formed to have an appropriate size, but in this way, the main surface (component mounting surface) of the board is reduced. Since it becomes narrow, another problem of hindering downsizing of the electronic circuit unit occurs.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide an electronic circuit unit that can be reduced in size and thickness while securing the mounting strength of the shield cover.

  In order to achieve the above object, in the electronic circuit unit of the present invention, the circuit board is mounted on the main surface and has a plurality of concave grooves on the side surface, and a side electrode is provided on the inner wall surface of these concave grooves. And a shield cover made of a metal plate having a top plate covering the main surface of the substrate and a leg piece inserted into the concave groove and soldered, and at least a part of the plurality of concave grooves A step formed by communicating in the width direction a deep groove portion into which the leg piece is inserted by a groove deeper than the plate thickness of the leg piece and a shallow groove portion adjacent to the deep groove portion by a groove shallower than the deep groove portion. The groove was made into a structure.

  In this way, the concave groove of the stepped structure consisting of the deep groove portion and the shallow groove portion compensates the solder amount, which tends to be insufficient only by filling the deep groove portion into which the shield cover leg piece is inserted, with the solder in the shallow groove portion. Therefore, it is easy to increase the soldering strength to the leg pieces in the concave groove. In addition, even if a shallow groove part shallower than the deep groove part is formed next to the deep groove part, the effective area of the main surface (component mounting surface) of the board is hardly affected. There is little risk of hindrance. Therefore, the electronic circuit unit can be easily reduced in size and thickness while securing the mounting strength of the shield cover.

  In the above configuration, the concave groove of the stepped structure preferably includes the deep groove portion and a pair of shallow groove portions arranged in parallel on both sides in the width direction of the deep groove portion, thereby reducing the size of the substrate. Since the amount of solder in the concave groove can be increased by a pair of shallow groove portions that are less likely to cause trouble, the mounting strength of the shield cover can be increased without difficulty. In this case, if the deep groove portion is a semicircular groove wider than the leg pieces of the shield cover, and the shallow groove portion is a semicircular groove having a smaller diameter than the deep groove portion, a large number of large grooves are used. In the process of manufacturing the electronic circuit unit to be removed, it is possible to easily form a concave groove of a desired shape by simply drilling three circular through-holes (through-holes) in succession in the large-sized substrate, thereby reducing the manufacturing cost. More preferable.

  The electronic circuit unit of the present invention has a stepped structure in which a solder amount that tends to be insufficient simply by filling a deep groove portion into which a leg piece of a shield cover is inserted on a side surface of the substrate can be supplemented by solder in the shallow groove portion. By providing a concave groove, it is possible to increase the soldering strength to the leg piece with little effect on the effective area of the main surface (component mounting surface) of the board, so it is compact while ensuring the mounting strength of the shield cover It is easy to reduce the thickness.

  An embodiment of the invention will be described with reference to the drawings. FIG. 1 is an external view of an electronic circuit unit according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the electronic circuit unit, and FIG. FIG. 4 is a partial plan view of a large-sized substrate including the substrate.

  The electronic circuit unit shown in FIGS. 1 and 2 is a VCO (voltage controlled oscillator) that constitutes a local oscillator in a mobile phone or the like. In the electronic circuit unit, a wiring pattern (not shown) is formed on a main surface 1a of a substantially rectangular substrate 1 in plan view, and circuit components (not shown) such as a varicap diode, a capacitor, and a transistor are mounted. . Three types of concave grooves 2 to 4 are formed at a plurality of locations on the side surface of the substrate 1, and side electrodes 5 functioning as input / output terminals and ground terminals are provided on the inner wall surfaces of the concave grooves 2 to 4. Yes. The main surface 1a of the substrate 1 is covered with a shield cover 6 made of a metal plate, and the four leg pieces 7 projecting from the shield cover 6 are placed in the recessed groove 3 or the recessed groove 4 of the substrate 1. Inserted and electrically and mechanically connected by solder 8.

  The base material of the substrate 1 is, for example, glass-filled epoxy resin or the like, and the side electrodes 5 in the quarter-circular concave grooves 2 formed at the four corners of the side surface function as input terminals or output terminals. Both the side electrode 5 in the groove 3 formed on the long side surface of the substrate 1 and the side electrode 5 in the groove 4 formed on the short side surface function as ground terminals. The former groove 3 has a two-stage structure (stepped structure) in which grooves having different depths are communicated in the width direction. That is, the concave groove 3 formed on the long side surface of the substrate 1 includes a deep groove portion 3a into which the leg piece 7 of the shield cover 6 is inserted, and a pair of shallow groove portions adjacent to both sides in the width direction of the deep groove portion 3a. 3b, and both shallow groove portions 3b are juxtaposed so as to widen the opening of the deep groove portion 3a. Here, the deep groove portion 3a is a semicircular groove deeper than the plate thickness of the leg piece 7, and each shallow groove portion 3b is a semicircular groove having a smaller diameter than the deep groove portion 3a.

  The shield cover 6 is formed by bending a metal plate into a box shape. The top plate portion 6a covers the main surface 1a of the substrate 1, and the side cover 6b extends from the four sides of the top plate portion 6a to the substrate 1 side. Each leg piece 7 is provided in a protruding manner. Each side wall 6b is provided with a stopper piece 6c that is shorter than the leg piece 7. The lower end of the stopper piece 6c is brought into contact with the main surface 1a, whereby a shield cover on the substrate 1 is provided. A height position of 6 is defined. This shield cover 6 is for electromagnetically shielding circuit components mounted on the main surface 1a of the substrate 1.

  When manufacturing the electronic circuit unit configured as described above, first, a large substrate 10 as shown in FIG. 4 is manufactured. The large substrate 10 is divided into regions corresponding to a large number of units by lattice-shaped dividing grooves 11 and 12 extending vertically and horizontally, and through holes 13, 14, 15 a and 15 b are formed at appropriate positions on the dividing grooves 11 and 12. It is installed. Of these, the through-hole 13 positioned on the intersection of the vertical and horizontal dividing grooves 11 and 12 becomes a concave groove 2 when divided into four equal parts, and the through-hole 14 positioned on one of the divided grooves 12 is divided into two equal parts. And the groove 4 is formed. Further, on the other divided groove 11, a composite through hole 15 is formed in which a pair of through holes 15b having a smaller diameter than the through hole 15a are arranged side by side at a position partially overlapping with the through hole 15a. The through-hole 15 becomes a concave groove 3 when divided into two equal parts. That is, when the through hole 15a is divided into two equal parts, the deep groove part 3a is formed, and when the through hole 15b is divided into two equal parts, the shallow groove part 3b is formed. These through holes 13, 14, 15 a, 15 b are formed by punching circular through holes (through holes) in the large substrate 10.

  As the next manufacturing process, a wiring pattern (not shown) is formed for each region divided by the dividing grooves 11 and 12 on the large-sized substrate 10, and side surfaces are formed on the inner wall surfaces of the through holes 13 and 14 and the composite through hole 15. The electrode 5 is formed. Then, after mounting circuit components (not shown) in each region on the large substrate 10 and soldering to the wiring pattern, the leg pieces 7 of the shield cover 6 disposed so as to cover the circuit components are inserted into the through holes 14. And it inserts in the through-hole 15a of the composite through-hole 15, and solders. That is, by fixing the four leg pieces 7 of the shield cover 6 with the solder 8 filled in the through hole 14 and the solder 8 filled in the composite through hole 15, the shield cover is provided in each region on the large-sized substrate 10. 6 is attached.

  Thereafter, the large substrate 10 is cut along the dividing grooves 11 and 12 with a dicing blade or the like, so that a large number of electronic circuit units as shown in FIG. 4 and the composite through hole 15 becomes the concave groove 3.

  As described above, the electronic circuit unit according to the present embodiment has the concave groove 3 having the two-stage structure including the deep groove portion 3 a and the shallow groove portion 3 b on the side surface on the long side of the substrate 1, and the four shield covers 6. Two of the leg pieces 7 are inserted into the respective concave grooves 3 and soldered. And since this ditch | groove 3 can supplement the solder amount which is apt to be insufficient only by filling in the deep groove part 3a in which the leg piece 7 is inserted, the solder for the leg piece 7 can be supplemented. Easy to increase the attachment strength. Further, even if the shallow groove portion 3b shallower than the deep groove portion 3a is formed on both sides of the deep groove portion 3a, the effective area of the main surface 1a (component mounting surface) of the substrate 1 is hardly affected. Even if is added, there is little risk of hindering the downsizing of the substrate 1. Therefore, this electronic circuit unit can be easily reduced in size and thickness while securing the mounting strength of the shield cover 6.

  Further, in the present embodiment, the concave groove 3 is a semicircular groove whose deep groove portion 3a is wider than the leg piece 7 of the shield cover 6, and each shallow groove portion 3b is a semicircle having a smaller diameter than the deep groove portion 3a. Since the groove has a shape, it is possible to easily form the groove 3 having a desired shape by simply drilling three circular through-holes (through-holes) continuously in the large substrate 10 during the manufacturing process of the electronic circuit unit. be able to. Therefore, in this electronic circuit unit, the recessed groove 3 having a two-stage structure does not cause an increase in cost, and the mounting strength of the shield cover 6 can be increased without increasing the manufacturing cost.

  In this embodiment, the concave groove 4 formed on the side surface on the short side of the substrate 1 and into which the leg piece 7 of the shield cover 6 is inserted does not have a stepped structure. 7 is securely soldered in the groove 3 having a two-stage structure, so that the mounting strength of the shield cover 6 can be increased even if the remaining two leg pieces 7 have insufficient soldering strength. There is no risk of hindrance.

  FIG. 5 is a plan view of the substrate of the electronic circuit unit according to the second embodiment of the present invention, and the portions corresponding to those in FIG.

  In the second embodiment example shown in FIG. 5, the shape of the concave groove 3 having a stepped structure formed on the side surface on the long side of the substrate 1 is different from the first embodiment example described above. That is, in FIG. 5, the concave groove 3 formed in the substrate 1 includes a deep groove portion 3a into which a leg piece of the shield cover is inserted, and a pair of shallow grooves arranged in parallel so as to widen the opening of the deep groove portion 3a. The deep groove portion 3a is a semicircular groove as in the first embodiment, but each shallow groove portion 3c has a horizontally long shape with a substantially uniform groove depth. Also in this case, the solder amount that tends to be insufficient only by filling the deep groove portion 3a into which the leg piece of the shield cover is inserted can be supplemented by the solder in each shallow groove portion 3c. Is easy to increase. In addition, even if the shallow groove portion 3c shallower than the deep groove portion 3a is formed on both sides of the deep groove portion 3a, the effective area of the main surface 1a (component mounting surface) of the substrate 1 is hardly affected. Even if it is added, there is little risk of hindering downsizing of the substrate 1.

1 is an external view of an electronic circuit unit according to a first embodiment of the present invention. It is a disassembled perspective view of this electronic circuit unit. It is a top view of the board | substrate with which this electronic circuit unit is equipped. It is a partial top view of the large format board | substrate containing this board | substrate. It is a top view of the board | substrate with which the electronic circuit unit which concerns on the example of 2nd Embodiment of this invention is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 1a Main surface 2, 3, 4 Concave groove 3a Deep groove part 3b, 3c Shallow groove part 5 Side electrode 6 Shield cover 6a Top plate part 7 Leg piece 8 Solder 10 Large format board 11, 12 Divided groove 13, 14, 15a, 15b Through hole 15 Composite through hole

Claims (3)

  A circuit board is mounted on the main surface and a plurality of concave grooves are provided on the side surface, and a side electrode is provided on the inner wall surface of the concave grooves, a top plate portion covering the main surface of the substrate, and the concave grooves And a shield cover made of a metal plate having a leg piece to be inserted and soldered, and at least a part of the plurality of concave grooves is inserted into a groove deeper than the plate thickness of the leg piece. An electronic circuit unit comprising: a deep groove portion having a stepped structure in which a deep groove portion and a shallow groove portion adjacent to the deep groove portion which are shallower than the deep groove portion are communicated in the width direction.   2. The electronic circuit unit according to claim 1, wherein the concave groove of the stepped structure includes the deep groove portion and a pair of shallow groove portions arranged in parallel on both sides in the width direction of the deep groove portion.   The deep groove portion according to claim 2, wherein the deep groove portion is a semicircular groove wider than the leg pieces, and the shallow groove portion is a semicircular groove having a smaller diameter than the deep groove portion. Electronic circuit unit to do.

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