JP2000323800A - Printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of electronic parts mounted in a printed wiring board by static electricity applied to the substrate from the outside. SOLUTION: The static electricity applied to a printed wiring board is led to a metallic enclosure 6 so as to prevent the electricity from flowing in electronic parts mounted in the wiring board, by closely facing tooth-shaped lands 2 integrally formed with power/signal lines 1 wired on the wiring board by printing and tooth-shaped lands 5 integrally formed with a grounding line 4 to each other with a gap (g) between the sharp tip sections of the lands 2 and 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a printed wiring board in which electronic components such as semiconductors, ICs, and LCIs mounted on the printed wiring board are protected from damage caused by static electricity.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional printed circuit board mounting structure in which measures against static electricity are taken. In FIG. 4, 1
1 is a metal housing, 12 is a printed wiring board on which electronic components such as semiconductors, ICs, LCIs, etc. are mounted, 13 is one end fixed to the printed wiring board 12 with screws or solder, and the other end is brought close to the metal housing 11. Terminal board. l2 is a terminal plate that absorbs static electricity and drops it to the earth of the rotating body. Static electricity indicated by an asterisk (*) generated on the surface of the printed wiring board 12, switches, etc., is dropped to ground through the metal casing 11,
In order to further promote this, a gap is provided between the tip of the terminal plate 13 and the metal housing 11 to generate static electricity there, and discharge from the metal housing 11 to the ground.

[0003]

However, in the conventional countermeasures against static electricity, a terminal plate 13 for discharging static electricity from the printed wiring board 12 is required, so that the number of components is increased, and the leading end portion and the metal housing are required. It is necessary to properly manage and install the gap between the body 11 and the body 11, and there is a problem that the number of man-hours for attachment increases.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a printed wiring board capable of taking a countermeasure against static electricity without increasing the number of parts and the number of mounting steps.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for manufacturing a printed circuit board, comprising: Lands are provided, and static electricity is collected on these lands and released to the earth through an earth line. This eliminates the necessity of attaching a terminal board as in the related art, and can prevent electrostatic breakdown of an electronic component attached to a printed wiring board without increasing the number of components and the number of attachment steps.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a land where a power / signal line and a ground line on a printed wiring board are opposed to each other is a land having an acute-angled tip portion which is close to and opposed to each other. It is a printed wiring board characterized by the fact that it is easy to collect static electricity at sharp points, and by placing a land with a sharp tip at the root of the part where static electricity easily enters, it is behind it It has the effect of preventing static electricity from flowing into the mounted electronic components and preventing electrostatic breakdown.

According to a second aspect of the present invention, there is provided the printed wiring board according to the first aspect, wherein the ground line is connected to a metal housing. It has the function of discharging to ground through the housing.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG. FIG.
Denotes a part of a printed wiring board, and 1 denotes a power / signal line, which has a component mounting hole land 1a at a tip thereof, and further extends from the component mounting hole land 1a, and has a sharp-edged tip. The land 2 is formed integrally. Reference numeral 3 denotes a resist for separating the component mounting hole land 1a and the sawtooth land 2 and forming a soldering land.
Each of the sawtooth lands 2 has a similar shape of the sawtooth lands 5 formed integrally with the ground line 4 and is closely opposed to each other with a gap g. The gap g is preferably as small as possible. Reference numeral 6 denotes a part of the metal housing connected to the ground line 4.

Next, the operation of this embodiment will be described. As shown in FIG. 2A, in a round component mounting hole land 14a formed at the tip of a power / signal line 14 in a conventional printed wiring board, static electricity is generated at a peripheral portion thereof, and power / signal Although it flows through the signal line 14 into an electronic component located therebefore and causes electrostatic breakdown, in the present embodiment, as shown in FIG. The generated static electricity is collected at the sharp end of the sawtooth land 2 and does not flow into the electronic components at the end of the power / signal line 1, so that electrostatic breakdown can be prevented. The static electricity collected at the tip of the sawtooth land 2 flows into the tip of the sawtooth land 5 located on the opposite side through the gap g, flows into the metal housing 6 through the ground line 4, and is dropped to ground. . The smaller the gap g is, the smaller the amount of static electricity can be discharged and dropped to the ground. In the present embodiment, the gap g is formed by pattern printing, so that the gap g is uniform and has less variation compared to the conventional terminal plate structure. Can be obtained. Therefore, the static electricity countermeasure structure according to the present embodiment can form a minute gap, and has an advantage of excellent mass productivity in discharging static electricity.

As described above, according to the present embodiment, the role of the conventional discharge terminal plate is replaced by the land of the printed wiring board, and the power / signal line 1 has the sawtooth land 2 and the earth line 4 has the sawtooth land 5. Is provided, it is possible to take a reliable countermeasure against static electricity with a simple structure.

In the above description, the saw-tooth land 2 is integrated with the component mounting hole land 1a. However, as another method, as shown in FIG. The same effect can be obtained even if the saw-tooth lands 2 and 5 are formed directly on the opposing portion of the ground line 4.

[0012]

As described above, according to the present invention, at the portion where the power supply / signal line and the ground line on the printed wiring board are opposed to each other, the lands which are close to each other and whose leading end portions are sharp are provided. Since the static electricity is collected on the land and released to the ground through the ground line, it is not necessary to mount the terminal board as in the past, and the electrostatic breakdown of the electronic components can be prevented without increasing the number of parts and the number of mounting steps. Can be.

[Brief description of the drawings]

FIG. 1 is a plan view showing a part of a printed wiring board according to an embodiment of the present invention.

FIG. 2A is a plan view showing a static electricity generation state in a conventional example. FIG. 2B is a plan view showing a static electricity generation state in the embodiment.

FIG. 3 is a plan view showing a part of a printed wiring board according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional printed wiring board device which has taken measures against static electricity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power / signal line 2 Serrated land 3 Resist 4 Earth line 5 Serrated land 6 Metal housing

Continuation of the front page (72) Inventor Akitaka Wakimoto 4-3-1 Tsunashimahigashi, Kohoku-ku, Yokohama-shi, Kanagawa F-term (reference) in Matsushita Communication Industrial Co., Ltd. 5E338 CC01 CC04 CC06 CC07 CD12 CD22 EE12

Claims (2)

[Claims] 1. A printed wiring board, characterized in that, at a portion where a power supply / signal line and an earth line on the printed wiring board face each other, a land having an acute-angled tip that is close to and opposed to each other is provided. 2. The printed wiring board according to claim 1, wherein said ground line is connected to a metal housing.