JPS6138218Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed circuit board circuit unit suitable for assembly as a circuit block on a large main printed circuit board.

In electronic equipment, parts related to electronic circuits are mounted on printed circuit boards and housed in cases together with mechanical parts. It is preferable to reduce the number of substrates and combine them into one printed circuit board if possible.

However, when many electronic components are directly attached to a single printed circuit board, it becomes very complicated when changes to the electronic circuit are requested during the device development process, especially after the printed circuit board has been designed or manufactured. Since the pattern design of the printed circuit board must be re-designed, it takes time to re-design, which creates another problem in that the development period has to be extended.

In addition, when many electronic components are attached to a single printed circuit board, the work becomes extremely troublesome, and electrical inspection after attachment becomes complicated.

Therefore, in order to solve the above-mentioned problems, circuits that are basic to equipment and rarely change, such as power supply circuits, are mounted directly on the main printed circuit board, and their contents are mounted directly on the main printed circuit board, such as functional circuit blocks. A printed circuit board circuit unit is constructed by attaching electronic components of circuit parts that are often changed or added or removed to a printed circuit board separate from the main printed circuit board, and this circuit unit is electrically It is common practice to assemble it onto the main printed circuit board after inspecting it.

By assembling the printed circuit board circuit unit onto the main printed circuit board in this way, when changing a part of the electronic circuit or adding a function during the development process, it is possible to assemble the large and complex main printed circuit board. Because it is sufficient to simply redesign or newly design the printed circuit board of the circuit unit without making any changes, the development period will not be significantly extended in response to new requirements that arise during the development process. We can respond in a short period of time. Furthermore, since each circuit unit can be handled as a unit, electrical inspection can be easily performed for each circuit unit, and the work of mounting it on a printed circuit board becomes easier.

By the way, some of the above-mentioned printed circuit board circuit units include those that are electrically connected only to the electrical circuit of the main printed circuit board, and those that are electrically connected to both the electrical circuit of the main printed board and electrical components that are not on the main printed board, such as meters. There are those that are connected to the main printed circuit board, and those that are simply mounted on the main printed circuit board but are not electrically connected to the electrical circuit of the main printed board at all, and are connected only to electrical members that are not on the main printed circuit board.

However, conventionally, in both of the above cases, lead members such as lead terminals and terminal pins for connecting the circuit of the circuit unit to the circuits and electrical components of the main printed circuit board are connected to the electrode pattern of the printed circuit board. Therefore, when a force is applied to the lead member, the lead member and the electrode pattern come off from the printed circuit board.
Furthermore, a very large-scale mounting means is required to attach the circuit unit to the main printed circuit board, resulting in high cost and large size.

This invention was made in view of the above points,
An object of the present invention is to provide a printed circuit board circuit unit that makes the attachment of lead members to the printed circuit board more reliable and eliminates the need for large-scale and complicated attachment means for attaching the circuit unit to the main printed circuit board. .

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an example of a printed circuit board circuit unit 10 according to the present invention. The circuit unit 10 includes a printed circuit board 11 having a conductive pattern 11b printed on the lower surface of an insulating base 11a;
Electronic components 12a and 12b placed on the upper and lower surfaces of the printed circuit board 11 and electrically connected to the conductive pattern 11b, and the printed circuit board 1
A lead terminal 13a as a lead member electrically connected to an electrode of a conductive pattern 11b provided on one side edge of the 1, and an electrode of a conductive pattern 11b provided on a side edge opposite to the side edge. a flexible printed circuit board 13b as a lead member electrically connected to the lead terminal 1 for the electrode;
Sealing portions 14a and 1 made by resin molding seal the connection portions of 3a and flexible substrate 13b.
4b.

The printed circuit board 11 is shown as being based on a resin board made of phenol, epoxy, etc., with a conductive pattern 11b printed only on its lower surface, but it may also be made of a metal board made of iron, copper, etc. It is also possible to use a base made of a plate with an insulated surface, or a base with conductive patterns printed on both sides.

The electronic component 12a is attached to the printed circuit board 11 by inserting the legs of the component 12a from the top side into holes made in the printed circuit board 11, and by soldering the ends of the legs to the conductive pattern 11b on the bottom surface. On the other hand, the electronic component 12b, which is a face bonding component, is attached by directly soldering to the conductive pattern.

The tip of the lead terminal 13a is bifurcated, and the side edge of the printed circuit board 11 is held between the bifurcated portion, and in this state, the tip of the lead terminal 13a is soldered to the electrode portion of the conductive pattern 11b. is attached to the printed circuit board 11 by spot welding. The free end side of the lead terminal 13a attached to the printed circuit board 11 is slightly extended along the surface of the printed circuit board, and then bent at right angles to the surface of the printed circuit board 11 to face the conductive pattern surface of the printed circuit board 11. It is prominent.

On the other hand, as shown in FIG. 3, the flexible substrate 13b is formed by sandwiching a plurality of lead patterns 13b ₃ between two flexible insulating sheets 13b ₁ and 13b ₂ in the form of a sandwich arch. At one end connected to the printed circuit board 11, one insulating sheet 13b ₁ is partially removed, and a land portion at one end of the lead pattern 13b ₃ is exposed.

When connecting the flexible board 13b as described above to the printed circuit board 11 by soldering,
As shown in FIG _{. 3 ,} the center of the land portion of the lead pattern 13b3 is cut out along with the insulating sheet _13b2 toward the side edge, and as shown in FIG. pattern 13
The flexible substrate 13b is positioned with respect to the printed circuit board 11 in contact with the electrode b and the electrode and the land portion correspond to each other, and in this state, the solder 1 is applied to the cutout portion 13b ₃ '.

As a method of connecting the flexible board 13b to the printed circuit board 11, there is a reflow soldering method using solder paste or epoxy solder. When using this method, as shown in FIG. 5, the flexible board 13b of FIG. Excision 13
b ₃ ′ is not performed, the land portion of the lead pattern 13b ₃ is connected to the conductive pattern 1 of the printed circuit board 11.
Solder paste or epoxy solder 16 to electrode 1b
The solder paste or epoxy solder 16 may be cured by positioning the solder paste or epoxy solder 16 with respect to the printed circuit board 11 so as to face the solder paste or the epoxy solder 16 by moving the heating head 17 in the direction of the arrow in this state and applying heat.

At the other end of the flexible substrate 13b, one end of which is connected to the printed circuit board 11 as described above, there is a meter consisting of a display 18 made by positioning a plurality of light emitting elements 18a by resin molding as shown in FIG. A magnetic head, etc. is connected to it. If a meter or magnetic head is connected, circuit unit 1
0 is configured as a meter circuit or a magnetic head circuit, respectively.

The above-mentioned sealing parts 14a and 14b strengthen the mechanical strength of the connection between the lead terminal 13a and the flexible substrate 13b to the printed circuit board 11, and prevent the terminal 13a and the flexible substrate 13b from peeling off from the printed circuit board 11. However, if this is made to protrude a certain height in the protruding direction of the lead terminal 13a, that is, toward the surface of the conductive pattern 11b of the printed circuit board 11, then when the circuit unit 10 is attached to the main printed circuit board X shown by the broken line in FIG. Since a constant distance is maintained between the main printed board X and the printed board 11 of the circuit unit 10, electronic components are placed on the surface of the main printed board However, the component 12b of the circuit unit 10 never comes into contact with this component.

When the circuit unit 10 is attached to the main printed circuit board X as described above, the lead terminals 13a are soldered and fixed to the conductive patterns of the main printed circuit board X, but if only this part is applied, the opposite side will lift when external force is applied. Therefore, as shown in the figure, a protrusion 14b' is integrally provided on the sealing part 14b.
By inserting this protrusion 14b' into the hole of the main printed circuit board X and welding it on the bottom surface, the circuit unit 1
0 can be reliably attached to the main printed circuit board X.

The structure of the protrusion 14b' for attaching the circuit unit 10 to the main printed circuit board X is as shown in FIG. A self-tapping screw N is screwed into the main printed circuit board X from the bottom side of the main printed circuit board
A conceivable option is to form a hole x and press-fit it into a hole x of the main printed circuit board X.

FIG. 7 shows a printed circuit board circuit unit 10' which does not need to be electrically connected to the main printed circuit board and can simply be attached, and the flexible board 13 is replaced with the lead terminal 13a of FIG.
a′ is connected. In this case as well, both sealing portions 14a and 14b are provided with protrusions as shown at 14b' in FIG. 2 for attachment to the main printed circuit board.

In the example shown in FIG. 1, it is convenient if the lead terminals 13a are spaced at the same inch pitch as the IC, since the circuit unit can be handled in the same way as the IC.

Next, a method of manufacturing the circuit unit shown in FIGS. 1 and 2 will be explained.

First, as _shown in FIG.
A printed circuit board ₁₁ is prepared, in which electronic components 12a and 1 are provided on both sides.
2b is attached to a large number of products. As shown in FIG. 8, the printed circuit boards 11 are placed with the conductive pattern side facing up, the distance between them kept constant, and the side edges where the electrodes 11b ₁ and 11b ₂ are provided facing outward. A large number of printed circuit boards 11 are arranged in a line on the same surface so that the printed circuit boards 11 are located on the same surface.

Next, a lead frame 20 is constructed in which a large number of lead pieces 20a, each serving as a lead terminal, are supported on a common frame 20b at intervals equal to the interval between the electrodes _11b1 on one side edge of the aligned printed circuit board 11. A flexible board is prepared in which a large number of lead patterns 30a, each connected to an electrode 11b ₂ of a printed circuit board 11, are supported on an insulating sheet 30b at intervals equal to the intervals of the aligned electrodes 11b ₂ of the printed circuit board 11. Prepare 30. In particular, the insulating sheet 30b of the flexible substrate 30 is formed with a weakened portion 30c that makes it easier to later separate the flexible substrate 30 corresponding to each printed circuit board 11.

Then, as shown in FIG. 8, the lead frame 20 and flexible substrate 30 are positioned so that the lead piece 20a and the lead pattern 30a face the electrodes 11b ₁ and 11b ₂ to be connected, respectively, and then direction, and bring the corresponding lead pieces 20a and lead patterns 30a into contact with the electrodes 11b ₁ and 11b ₂ of the printed circuit board 11, respectively.

In this state, the lead piece 20a and the electrode 11b ₁ are connected by soldering or spot welding, and the lead pattern 30a is soldered to the electrode 11b ₂ by the method described above with respect to FIGS. 3 to 5. . The connection work of the lead pieces 20a and the lead patterns 30a to the electrodes 11b ₁ and 11b ₂ can be performed on a large number of printed circuit boards 11 at the same time.

Through the above operations, a large number of printed circuit boards 11 interconnected by lead frames 20 and flexible substrates 30 are then placed on the lower die 40a of the molding die, as shown in FIG. Type 4
Put 0b on it. Then, the lower mold 40a and the upper mold 40b
A sealing material made of a resin material is filled in the molded part between the lead pieces 20a and the lead pattern 30 for the electrodes 11b ₁ and 11b ₂ of the printed circuit board 11.
The connection portions of a are sealed 14a and 14b, respectively.

FIG. 10 shows a state in which the sealing material is removed from the mold after curing. As can be seen from the figure, the sealing part 14a
and 14b are limited to only the connection portions of the lead piece 20a and the lead pattern to the electrodes of the printed circuit board 11, and the components 12a and 12b on the printed circuit board 11 are not sealed, so repairs by replacing parts or electrical Adjustments can be made easily. Further, since the connecting portion is firmly fixed to the base 11a of the printed circuit board 11 by the sealing portions 14a and 14b, the lead frame 20 and the flexible substrate 30 do not come off from the printed circuit board 11.

To complete the circuit unit 10 shown in FIG. 1 from the state shown in FIG.
While removing a portion of the common frame 20b,
It is sufficient to separate the flexible substrate 30 at the weakened portion 30c and bend the lead piece 20a at right angles to the surface of the printed circuit board 11, thereby making it possible to produce a large number of printed circuit board circuit units 10 at once.

To manufacture the circuit unit 10' shown in FIG. 7, two sets of flexible printed circuit boards 30 and 30' connected to electrodes 11b ₁ and 11b ₂ of the printed board 11 are positioned as shown in FIG. , then a lead pattern 30a is attached to the corresponding electrode.
and 30a' are respectively connected, and then the connection portions are sealed, and then the flexible substrates 30 and 30' are separated at the weakened portions 30c and 30c'.

As described above, the present invention electrically connects the lead member to the electrode formed on the side edge of the printed circuit board, seals the connecting portion by resin molding, and integrates the main printed circuit board with this sealed portion. It is formed by forming a protrusion for attachment to.

Therefore, the connecting portion of the lead member to the electrode is integrated with the printed circuit board by the sealing portion, and the lead member does not easily come off from the printed circuit board.
The protrusions molded integrally with the sealing part are used to attach the circuit unit, and there is no need for large-scale attachment means to attach the circuit unit to the main printed circuit board, which is effective for cost reduction and miniaturization. Excellent practical effects can be obtained.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a sectional view, respectively, showing an embodiment of a printed circuit board circuit unit according to the present invention, and FIG. 3 is a perspective view showing an enlarged specific example of a part of FIGS. 1 and 2. Figures 4 and 5 are enlarged cross-sectional views of specific examples of parts of Figures 1 and 2, and Figures 6a and b are cross-sectional views of modified examples of parts of Figure 2. 7 is a perspective view showing another embodiment of the printed circuit board circuit unit, FIGS. 8 to 10 are perspective views showing the manufacturing process of the circuit unit shown in FIGS. 1 and 2, and FIG. FIG. 8 is a perspective view showing one manufacturing process of the circuit unit shown in FIG. 7; 10...Printed circuit board circuit unit, 11...
Printed circuit board, 11b ₁ , 11b ₂ ...electrode, 13a
...Lead terminal (lead member), 13b...Flexible printed circuit board (lead member), 14a,
14b...Sealing part, 14b', 14b'', 14b...
...Mounting protrusion, X...Main printed circuit board.

Claims (1)

[Scope of utility model registration request] A lead member is electrically connected to the electrode formed on the side edge of the printed circuit board, the connecting portion is sealed by resin molding, and a protrusion for attachment to the main printed circuit board is formed integrally with this sealed portion. A printed circuit board circuit unit.