JP2575376Y2 - PCB shielding equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a shield device for a printed circuit board in which high-frequency radio waves do not leak from a printed circuit board on which electronic components are mounted and the respective components are electrically connected by printed wiring. About.

[0002]

2. Description of the Related Art Conventionally, this type of device has a box-shaped shield cover made of a conductive metal material that covers a printed circuit board to prevent high-frequency radio waves from leaking from the printed circuit board and to prevent other devices from being used. Was trying to avoid radio interference.

[0003]

However, even with the above-mentioned conventional structure, if the ground wire printed on the substrate is too thin or a large current flows through the ground wire, the ground wire is not used. Is slightly floating from the true ground, and its function as a true ground wire is weakened. for that reason,
Even if a ground wire is printed near the high-frequency signal line, high-frequency radio waves sometimes leak to the outside. SUMMARY OF THE INVENTION The present invention has been made to address the above-described problem, and an object of the present invention is to provide a shield device for a printed circuit board in which leakage of high-frequency radio waves is suppressed as much as possible.

[0004]

In order to achieve the above object, the constitution of the present invention is characterized in that both ends of a U-shaped body formed of a conductive and flexible material in a substantially U-shape are fixed to a printed circuit board. And at least one end is electrically connected to a ground wire printed on the printed circuit board, and the central apex thereof is brought into contact with a conductive shield cover covering the printed circuit board. is there.

[0005]

[Effects and Effects of the Invention] In the present invention configured as described above, the ground wire printed on the printed circuit board is U-shaped.
It is connected to the shield cover via the character, and since the cover has a large capacity, the ground wire is reliably grounded and performs its original function sufficiently. Therefore, since the ground wire suppresses the leakage of high-frequency radio waves from the high-frequency signal line on the printed circuit board, the leakage of high-frequency radio waves from the printed circuit board is sufficiently suppressed, and no radio interference is caused to external devices. In addition, since the U-shaped body is fixed to the printed board at both ends, the U-shaped body is firmly supported by the printed board and can be securely connected to the shield cover. Grounded.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the relationship among a frame 10, a printed circuit board 20, and a shield cover 30.
FIG. 2 is a sectional view showing a state in which the printed circuit board 20 and the shield cover 30 are assembled on the frame 10.

The frame 10 is made of a conductive metal material such as iron, and is fixed to the main body of the device. Printed circuit board 2
Numeral 0 is made of an insulating material, and a copper foil strip 21 is printed on its front and rear surfaces along its periphery. Various electronic components 22 are mounted in the center of the printed circuit board 20. The components 22 are electrically connected by various wirings 23 printed on the printed circuit board 20 as shown in FIG. I have. The shield cover 30 is formed by bending a conductive metal plate such as iron into a rectangular parallelepiped shape, and a long flange 31 is integrally formed therearound. These printed circuit board 20 and shield cover 3
0 is fixed on the frame 10 by screws 40. In this case, the shield cover 30 is
It is also electrically connected to the frame 10 via the screws 40 and the copper foil strip 21, and the cover 30 is reliably grounded.

[0008] A pair of holes 24 are provided at positions of the ground line 23 a of the wiring 23 of the printed circuit board 20.
The U-shaped body 25 is assembled at both ends and soldered and fixed. In this case, both ends of the U-shaped body 25 may be formed in a T-shape as shown in FIG. 4 or may be formed in a U-shape as shown in FIG. This U character 2
Numeral 5 is made of conductive and flexible nickel silver, and its central apex portion comes into compression contact with the inner peripheral surface of the shield cover 30.

In the above-described embodiment, the U-shaped body 25 is firmly fixed on the printed circuit board at both ends thereof, and the central apex is crushed by the shield cover 30 to form the U-shaped body 25. Contact securely on the inner peripheral surface. The shield cover 30 is connected to the frame 10 and has a large capacity.
The ground wire 23a on the ground wire 0 is securely grounded. Even if the ground wire 23a is slightly thin or a large current flows through the ground wire 23a, the ground wire 23a is reliably grounded and its original function is sufficiently performed. Demonstrate. Accordingly, since the ground wire 23a suppresses the leakage of high-frequency radio waves from the high-frequency signal line on the printed circuit board 20, the leakage of high-frequency radio waves from the printed circuit board 20 is sufficiently suppressed, and no radio interference is caused to external devices. FIG. 6 shows a measurement result of unnecessary radiation in an anechoic chamber when a high-frequency signal is excited in a part of the printed circuit board 20. FIG.
(B) is a U-character 25
It is a measurement result in the case where was provided. According to this, when the frequency of the high-frequency signal is about 50 to 200 MHz, the U-shaped
It can be understood that the effect of suppressing the electric wave leakage due to the above appears remarkably.

Further, as shown in FIG. 3, according to the above-described embodiment, the crystal oscillator and the CPU
Since the U-shaped body 25 is provided on the ground wire 23a near the positions 26 and 27 of the printed circuit board 20 on which the radio wave is arranged, it is possible to particularly better prevent radio wave leakage due to a high frequency signal.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a relationship between a frame, a printed circuit board, and a shield cover.

FIG. 2 is a cross-sectional view in a state where a printed board and a shield cover are assembled to a frame.

FIG. 3 is a partial plan view of the printed circuit board, showing a part of the printed circuit board in detail;

FIG. 4 is a perspective view showing an example of a relationship between a U-shaped body and a printed board.

FIG. 5 is a perspective view showing another example of the relationship between the U-shaped body and the printed circuit board.

FIG. 6 is a measurement graph of unnecessary radiation of a high-frequency signal.

[Explanation of symbols]

10 ... frame, 20 ... printed circuit board, 21 ... copper foil strip,
22 electronic components, 23 wiring, 23a earth wire, 24
... holes, 25 ... U-shaped body, 30 ... shield cover, 40 ... screws.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 9/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A printed circuit board on which electronic parts are mounted and each of the parts is electrically connected by printed wiring.
In a shield device for a printed circuit board covered with a shield cover made of a conductor, both ends of a U-shaped body formed in a substantially U shape with a conductive and flexible material are fixed to the printed circuit board, and at least the one end is fixed. Is electrically connected to a ground wire printed on the printed circuit board, and a central apex thereof is in contact with the shield cover.