JPS58202600A - Printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a printed wiring board configured to suppress stray capacitance between the board and circuit components when, for example, a shielding board is attached to a printed wiring board on which an electronic circuit is mounted. Related to circuit devices.

[Background technology of the invention]

Not only in high-frequency circuits that receive high-frequency signals, but also in general electronic circuits, if an oscillator or rotating parts that cause magnetic flux leakage are used, the oscillation output or leakage magnetic flux may be transmitted to other circuits or other circuits in the same circuit. Install a shield plate to prevent this from affecting the Depending on how this shield plate is connected to the ground, the shielding effect will increase or decrease, and the influence on circuit components existing near this shield plate will also increase or decrease.

FIG. 1 is a plan view showing an example of the mounting structure of a shield plate attached to a printed wiring board on which a high frequency circuit is mounted.

The area surrounded by a square is a circuit housing 1, and a printed wiring board 2 is housed and fixed within this housing 1. This printed wiring board 2
Although actually more complicated, it is assumed that the first circuit section 3 and the second circuit section 4 are formed on an integrated board. and,
The shield plate 5 is grounded and attached so as to shield the first circuit section 3 and the second circuit section 4 , that is, the first circuit section 3 and the second circuit section 4 of the printed wiring board 1 . A mounting hole 6.6 is formed at the boundary, mounting legs 7.7 are formed at two locations on the shield plate 5, and a ground pattern 8 formed on the printed wiring board 1 is used for grounding. This ground pattern 8 is formed in a part of the second circuit section 4 side where circuit components (not shown) are not attached, and is arranged so that the shield plate 5 stands upright so as to be in contact with the boundary line with the first circuit section 4 side. The mounting 1117.7 is inserted into the mounting hole 6.6 and the mounting is fixed by soldering. 1 Here, reference numeral 9 indicates solder. This solder 9 is the shield plate 5
Mounting legs 7, 7 are mounted on the surface of the earth pattern 8 that is in contact with the boundary line.

With the above configuration, the shield plate 5 shields the first M section 3 and the second circuit section 4 so that they do not influence each other. The reason why the ground pattern is provided on the first circuit section 3 side and the shield plate 5 is not soldered from both sides is to effectively utilize the board area, and to connect the ground pattern to each first circuit section 3 side. Second circuit section 3
．． This is to prevent the circuits from being common to each other, thereby reducing the influence of the circuits on each other.

(Problems of the Background Art) However, an intuitive drawback of the mounting structure of the shield plate 5 is that the fixing force is weak. Furthermore, a more fatal drawback is that the shield plate 5 is located at a position that extends closer to the first circuit section 3 than the boundary line of the ground pattern 8. For this reason, the first circuit section 3
The stray capacitance between the circuit components and the shield plate 5 increases.

Such unnecessary stray capacitance causes a problem in that when the first circuit section 3 includes a resonant circuit or the like, the impedance of the resonant circuit fluctuates.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and the stray capacitance between the shield plate provided to prevent the functional blocks of the electronic circuit mounted on the printed wiring board from influencing each other and the circuit components used in the block is reduced. It is an object of the present invention to provide a printed circuit device in which the shield plate is attached so as to reduce the number of shields.

[Summary of the Invention] The present invention provides a structure in which a plate-shaped conductor is erected using a ground pattern formed on a printed wiring board, in which an end face of the plate-shaped conductor is disposed along a boundary line on either side of the ground pattern. is formed so that the second circuit section is shielded from the adjacent first circuit section via the ground pattern, especially when high frequency circuits are divided and mounted on a printed wiring board according to function. This is a type of shield structure in which the conductor end face of the shield plate for the second circuit is formed along one boundary line of the ground pattern, and the second circuit section is surrounded by the ground pattern and the seal plate.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on FIG. However, like FIG. 1, FIG. 2 shows a printed circuit device of a high frequency circuit, and the same elements are given the same reference numerals. First, the configuration of FIG. 2 will be explained.

The printed wiring board 2 is surrounded by a housing 1. Such a configuration is often found in tuner devices. On this printed wiring board 2, a first circuit section 3 and a second circuit section are divided and mounted according to function.
The circuit section 4 is constructed by attaching predetermined circuit components (not shown). These first. The second circuit section 3.4 is separated by a ground pattern 8.

This ground pattern 8 is provided to shield the second circuit section 4 from the first circuit section 3 or to form a wall strip line, etc. It is formed into a continuous band shape. A border line 11 in contact with the first circuit section 3 among the border lines 11a and 11b of this ground pattern 8
8tctsI1 cutout 3This cutout is formed by forming the mounting hole 12.12. This mounting hole 12.12 is connected to the second circuit section 4 for the first circuit section 3.
A shield plate 5 for spatially shielding the printed wiring board 2
It is provided to stand on top of the ground pattern, and its shape is rectangular, with one side extending along the boundary line 11a of the ground pattern 8.
It is formed in a nearly straight line.

On the other hand, the shield plate 5 is formed with mounting legs 7, 7 that can be inserted into the mounting holes 12. This leg 7.7 has a plate thickness surface 13°13 due to the thickness of the shield plate 5, and a leg end face 14.
14 is formed on the side, and is inserted into the mounting hole 12 and soldered. Needless to say, during this soldering, the solder 16 reaches three locations: one of the leg end surfaces 14.14 and the plate thickness surface 13.13. Further, the other end of the leg end surface 14.14 is the 26th
- In contact with the end surface of the circuit section 30 board.

The shield plate 5 is erected on the printed wiring board 2 as described above.

According to the above structure, when viewed from above, the ground pattern 8 appears to have a portion cut out for the mounting hole 6.6 by the mounting leg 7.7 of the shield plate 5. Therefore, the shield surface consists of the earth pattern 8 and the shield plate 5.
The second circuit section 4 is surrounded by a bank. In other words, the side end surface 15a of the shield plate 5 facing the first circuit section 3 substantially coincides with one boundary line 11a of the ground pattern 8, and the entire shield plate 5 is connected to the second circuit section 3.
It has entered the circuit section 4 side. As a result, stray capacitance between the shield plate 5 and the circuit components of the first circuit section 3 can be reduced, and good performance at high frequencies can be obtained. Furthermore, by inserting the shield 5 into the ground pattern 8, the space can be used more effectively and the overall size of the casing can be made smaller. Furthermore, there is an advantage that soldering is performed at three locations on the mounting leg 7, increasing the mounting strength.

Note that depending on the configuration method of the circuit device, the board on which the first circuit section 3 is mounted and the second circuit 81 on which the ground pattern 8 is formed may be used.
In some cases, the substrate 14 is formed separately and then joined within the housing 1. In this case as well, when the shield plate 5 is interposed between the boards, the legs of the shield plate 5 are made to fit into the ground pattern 8.

〔Effect of the invention〕

As described above, according to the present invention, the end face of the plate-shaped conductor is formed along the boundary line on either side of the earth pattern. It has the excellent effect of reducing stray capacitance between the capacitor and the circuit components mounted on the end face side.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional printed circuit device, and FIG. 2 is a plan view showing a printed circuit device according to the present invention. 2...Printed wiring board, 5...Plate conductor, 8...
Earth pattern, 11a, 11b... border line, 1
5a, i51+...Conductor end surface. 9- Figure 1 Figure 2

Claims (1)

[Claims] The present invention is characterized in that a plate-shaped conductor is erected from the printed wiring board, and the conductor end face is formed along one side of the conductor pattern formed on the printed wiring board and so that the main body enters inside the conductor pattern. Printed circuit device.