JPS6216016Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an LC filter in which a high-frequency coil and a capacitor are attached to a single substrate, and in particular an LC filter with a novel structure of electrodes for attaching leadless capacitors (hereinafter simply referred to as capacitors). The aim is to provide an LC filter with reliable capacitor connection and high manufacturing efficiency.

Conventionally, this type of LC filter has a high frequency coil 5 with a coil 3 wound around it attached to the main surface of a printed circuit board 1 as shown in FIG. 1
1 is well known. Note that 13 is a lead pin of the high frequency coil 5, which passes through the substrate 1 and is soldered to the circuit electrode 7. This LC filter is used by attaching terminal pins (not shown) to the substrate 1, for example, in parallel with the substrate.

In addition, when soldering the capacitor 9 or the lead pin 13 of the high-frequency coil to the circuit electrode 7 on the back side of the board 1, the LC filter should be placed approximately parallel to the solder surface during melting solder 17 as shown in the same figure. Soldering was done by dipping.

However, in recent years, the density of electronic components on circuit boards in electronic devices has increased, and when LC filters are attached to circuit boards, they are required to be thin and relatively flat. Therefore, LC filters have been proposed in which the high-frequency coil is placed on the top of the substrate instead of on the main surface of the substrate.

The present invention relates to the improvement of LC filters with a structure in which a high-frequency coil is placed on the top of the board, ensuring a reliable connection between the capacitor attached to the board and the circuit electrodes, and improving yield and manufacturing efficiency. It is something.

2A and 3 show an embodiment of the LC filter of the present invention, and the same parts as in FIG. 1 are designated by the same numbers. In the figure, 1 is the circuit electrode 11, 1
1' and 12 are formed by printing, vapor deposition, etc., and a drum core 6 around which a coil 3 is wound is formed on the upper end surface of the substrate 1, and a base 4 has lead pins 13 planted on the lower surface supporting the drum core. A high frequency coil 5 is mounted so as to rest on the lower surface of the base 4, and lead pins 13 of the high frequency coil are connected by soldering in parallel to high frequency coil connection electrodes 12 on the substrate 1. Reference numerals 11 and 11' designate a pair of capacitor connection electrodes that connect, for example, a chip-shaped capacitor 9 and an electrode, and the electrodes 11 and 11' are placed on the substrate 1 approximately parallel to the lower surface of the base 4 of the high frequency coil. The electrodes 11 and 11' are connected by soldering so that a capacitor 9 is passed between the electrodes 11 and 11'. That is, the electrodes of the capacitor 9 are also arranged parallel to the lower surface of the base 4. Terminal pins 19 are attached to the bottom of the board 1, and are used to connect the LC filter to a circuit board of an electronic device. Further, the high frequency coil connecting electrode 12 and the capacitor connecting electrodes 11, 11' are arbitrarily connected to form a desired LC filter and led out to the terminal pin 19. Note that the broken line 21 is a resin layer for the exterior.

Next, the outline of the manufacturing method of the LC filter of the present invention will be shown for reference.The LC filter of the present invention prepares a printed circuit board 1 on which a high frequency coil connection electrode 12 and capacitor connection electrodes 11, 11' are formed. , a base 4 on which a plurality of lead pins 13 are implanted
Drum core 6 is installed on top, and coil 3 is attached to that core.
After winding the coil, connect the lead of the coil to the lead pin 13.
A high-frequency coil 5 is made by connecting the high-frequency coil 5 to the base 4, and the high-frequency coil 5 is attached to the upper end surface of the substrate so that the lower surface of the base 4 of the high-frequency coil 5 overlaps the upper end surface of the substrate 1, and the upper end of the substrate 1 is held between the lead pins 13. At the same time, the chip-shaped capacitor 9 is attached to the capacitor electrode and the capacitor connecting electrode 1 using adhesive.
1 and 11' are temporarily fixed on the board, and then the board is dipped vertically into the melted solder of the solder tank 15 shown in FIG. Manufacture by hand.
In other words, in the LC filter of the present invention, the lead pins 13, capacitors 9, and terminal pins 19 of the high-frequency coil 5 to be connected on the substrate 1 are connected by immersing the entire front and back surfaces of the substrate 1 into molten solder 17. Therefore, the high frequency coil 5 can be manufactured without being immersed in the molten solder 17.

Now, the LC filter has capacitor 9 as shown above.
A thin LC filter can be realized if the high-frequency coil 5 is attached to the upper end of the substrate 1, but as in the present invention, the capacitor connection electrodes 11 and 11' on the substrate 1 are connected to the base of the high-frequency coil. Since it is arranged substantially parallel to the lower surface, it has the great advantage that the solder connection of the capacitor 9 is reliable. In other words, for example, as shown in FIG. 4A, the capacitor connection electrodes 11, 1
1' are arranged vertically with respect to the lower surface of the base 4, if the board 1 is immersed in the melted solder 17, the result will be B in the same figure.
A gap 23 is likely to be formed between the upper end of the capacitor 9 and the upper capacitor connection electrode 11' as shown in FIG. As a result, when the board 1 is pulled up, the lower end of the capacitor 9 and the lower capacitor connecting electrode 11 are connected by soldering, but the upper end of the capacitor 9 and the upper capacitor connecting electrode 11' are not connected by soldering. It occurs frequently (Figure C). On the other hand, in the LC filter of the present invention, the capacitor connection electrodes 11 and 11' are arranged parallel to the lower surface of the base 4 of the high-frequency coil, in other words, parallel to the surface of the melted solder, so that the substrate 1 is immersed from the bottom to the top. Even if you soak it,
Capacitor 9 and capacitor connection electrodes 11, 11'
A void 23 is no longer formed between the
The melted solder 17 penetrates into the fine details. Therefore, the connection and fixation of the capacitor 9 is ensured, and not only is there no connection failure and the yield is improved, but also the capacitor can be soldered reliably easily by simply arranging the capacitor connection electrodes 11, 11'. Connection becomes possible and manufacturing efficiency improves. Moreover, capacitor 9, coil lead, lead pin 1
3 and the terminal pin 19 can be soldered and connected at the same time.

Now, in the embodiment described above, an example was shown in which one high-frequency coil 5 was placed on the upper end of the substrate, but it goes without saying that two or more coils can be used arbitrarily. Moreover, the high-frequency coil 5 uses a core with only a lower flange and a winding core, omitting the upper flange, and by cutting the upper part of the winding core, the inductance of the high-frequency coil 5 can be adjusted even after it is attached to the substrate 1. Also,
The capacitor 9 is not limited to a chip type, and its size and shape can be arbitrarily formed as long as it is a small capacitor that does not require a lead wire and is provided with a connecting electrode. Further, capacitor connection electrodes 11, 1 to which the capacitor 9 is connected
It goes without saying that multiple pairs of electrodes 1' can be formed, and as long as each pair of electrodes 11 and 11' is substantially parallel to the lower surface of the base 4 of the high frequency coil, the position and size of the electrodes 11 and 11' can be freely determined. You can decide.

As explained above, in the present invention, a leadless capacitor is connected by soldering to capacitor connecting electrodes formed in pairs on a substrate, a high frequency coil having lead pins is placed on the upper end of the substrate, and the lead pins are connected to the substrate. In the LC filter, which is connected by soldering in parallel to the upper connection electrode, the pair of capacitor connection electrodes is arranged approximately parallel to the bottom surface of the high-frequency coil, so the connection of the capacitor is reliable and manufacturing efficiency is improved. It has the advantage of being able to provide a high LC filter.

[Brief explanation of the drawing]

Figure 1: A cross-sectional view showing a conventional LC filter.
FIG. 2: A front view showing an embodiment of the LC filter of the present invention. Figure 3: Side view of the LC filter shown in Figure 2. Figure 4: An explanatory diagram illustrating the soldered connection of the capacitor in the LC filter. 1: Substrate, 5: High frequency coil, 11, 11':
Capacitor connection electrode, 9: Capacitor, 13: Lead pin.

Claims (1)

[Scope of utility model registration request] Leadless capacitors are soldered and connected to capacitor connection electrodes formed in pairs on the board.
In an LC filter, a high-frequency coil with lead pins is mounted on the top end of the substrate, and the lead pins are soldered and connected in parallel to connection electrodes on the substrate, and a pair of capacitor connection electrodes are approximately parallel to the bottom surface of the high-frequency coil. An LC filter characterized by being arranged in.