JPH11121886A - Printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an inspector an inspector to recognize lead wire which number of fold it is merely by looking a printed circuit board by writing down a mark for identifying recognizing the number allotted to a lead wire, in the section where electronic parts are mounted, on a circuit board. SOLUTION: In an electronic part 1, a mark 4 is silk-printed on the surface of the solder resist of a printed wiring board, and this is of such scale marking that first ' ' is written down in the section corresponding to a first lead 3, and that '.' is written down at a specified interval, for example, every five numbers anticlockwise to the subsequent leads 3 in serial numbers. Since the printed circuit board is marked by this method, the discovery of the lead wire to be the target of test becomes easy at inspection, and if a user applies the test pin of a tester to the section between the lead and the land, he can perform the test on whether it is good or bad easily, as to the mounting condition or conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board on which electronic components having a large number of leads are mounted, and more particularly to a printed circuit board in which an inspector can easily find a lead having a specific number during an inspection or the like. It is.

[0002]

2. Description of the Related Art In a manufacturing process of a printed circuit board, electronic components are mounted on the printed circuit board through a solder layer or the like. After mounting the electronic components, an inspector applies test pins of a tester to each lead of the electronic components. In this way, a short or an open between the lead and the land (a part where the electronic component is mounted) is electrically inspected to determine whether the product is good or defective.

[0003]

However, if the electronic component to be mounted is a component having two or three leads, such as a capacitor or a transistor, the inspector can use the lead and the land (the part where the electronic component is mounted). ) Can be determined at a glance which lead and land (the part where the electronic component is to be mounted) are in a good or bad mounting state. When the component is an integrated circuit such as an IC or an LSI, the number of leads of the integrated circuit is increasing and the interval between each lead is very narrow. It is very difficult and almost impossible to identify the lead visually.

The present invention has been proposed to solve the above-mentioned problem. For example, a printed circuit board having a large number of leads and having mounted thereon electronic parts such as integrated circuits such as IC chips is provided at a factory. It is an object of the present invention to provide a printed circuit board that allows an inspector to easily identify the number of a lead only by looking at the printed circuit board during inspection.

[0005]

According to a first aspect of the present invention, there is provided a printed circuit board on which an electronic component having a large number of leads is mounted. Is characterized in that markings for facilitating the identification of the numbers assigned to the leads are marked on the parts where.

A printed circuit board according to a second aspect is characterized in that, in the first aspect, the marking is a scale marking written at predetermined intervals on the basis of a specific lead. A printed circuit board according to a third aspect is characterized in that, in the first or second aspect, the marking is silk-printed on the printed circuit board.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating an example of an electronic component mounted on a printed circuit board. In addition,
In the present invention, a QFP (Quadrate Flat Pack Pack) is used as an example of an electronic component mounted on a printed circuit board.
An explanation will be given using an IC (Age) type IC. As a pin insertion type, a DIP (Dual In-line packa) is used.
ge (type) IC, S-DIP (Shrink DIP) type IC, etc., as SOP (Smal
l Outline Package) type IC, TQF
It goes without saying that a P (Thin QFP) type IC may be used.

In the electronic component 1, 2 is a main body, and 3 is a lead. The mark 4 is silk-printed on the surface of the solder resist of the printed circuit board when the printed circuit board is created,
First, the scale corresponding to the first lead 3 is marked with “◎”, and the next consecutive lead 3 is marked counterclockwise at predetermined intervals, for example, at every 5th scale. Marking.

[0009] Here, the scale marking may be indicated by a dot or line scale without directly writing the number assigned to the lead, and can be sufficiently used as an identification display even in a narrow space. Such a marking can be applied to any printed circuit board prepared by an additive method as well as a printed circuit board prepared by a subtractive method.

[0010] In the present invention, since the marking is written on the printed circuit board by such a method, it is easy to find the lead to be tested at the time of inspection.
If a test pin of a tester is applied between the lead and a land (a part on which an electronic component is mounted), it is possible to easily test whether the mounting state or conductivity is good or bad.

In the illustrated example, the markings 4 are silk-printed every five leads 3 by counting the leads 3 in the counterclockwise direction of the electronic component 1. However, the markings may be counted in the clockwise direction of the electronic component 1. The interval may be changed. In addition, as a method of writing the marking 4 on the printed circuit board, not only silk printing, but also a method of writing with a conductor pattern, a method of not forming a solder resist, and the like may be appropriately selected.

As a method of writing with a conductor pattern, a printed circuit board is prepared by a subtractive method, and at this time, an etching resist is applied in a desired shape to a position where a marking 4 is to be written on a copper foil, and an etching process is performed. Good. On the other hand, when making a printed circuit board by the additive method,
When applying plating resist on an insulating substrate, the marking 4
Is provided in a desired shape at a position where a plating resist is not to be applied, and electroless copper plating may be applied.

In addition, when the printed circuit board is formed by either the subtractive method or the additive method, after the marking 4 is written with the conductor pattern, if the marking 4 is exposed on the surface of the printed circuit board, Since the conductor pattern has the property that solder is easy to ride, when soldering electronic components, there is a possibility that a solder bridge may be formed between the marking and the lead and the marking, It is desirable to apply a solder resist from above the marking 4.

As a method of not forming the solder resist, a solder resist is applied to a position where the marking 4 is to be written in a desired shape using a mask in which the solder resist is not applied, and the marking 4 is formed on the printed circuit board. As a place for marking 4, if a portion where a conductor pattern is present is selected at the time of forming a solder resist, the conductor pattern is exposed on the surface of the printed circuit board. When soldering parts,
A solder bridge may be formed between the markings and between the lead and the marking. Therefore, it is desirable that the place where the marking 4 is described is a place where there is no conductor pattern below the marking.

FIG. 2 is a plan view showing another example of an electronic component mounted on a printed circuit board. In the figure, the same components as those of the electronic component mounted on the printed circuit board shown in FIG.
The marking 4 is written on the surface of the solder resist of the printed circuit board when the printed circuit board is created. First, "(1)" is written at a position corresponding to the first lead 3, and "(1)" Starting from the counterclockwise direction of the electronic component 1, every three leads 3 are counted, and the numbers “(5)”, “(10)”, “(15)”, “ (20) "...

FIG. 3 is a plan view showing still another example of the electronic component mounted on the printed circuit board. In the figure, the same components as those of the electronic component mounted on the printed circuit board shown in FIG. As shown in the figure, corresponding to each lead 3,
The first lead 3 is marked with “•” and the other leads 3
, Vertical scale markings are written at regular intervals so that the inspector can easily identify the lead number.

If the scale marking is divided into thin lines at intervals of five lines and thick lines at intervals of ten lines, it is possible to more easily find leads to which specific numbers are assigned. Furthermore, although not shown in the drawings, the shape of the end of the corresponding conductor pattern may be thickened for each predetermined lead when the printed circuit board is formed.

[0018]

As can be understood from the above description, according to the printed circuit board of the first aspect, it is easy to identify the number assigned to the lead on the part on which the electronic component is mounted on the circuit board. Since the markings are written for the inspection, the inspector can easily find a specific lead at the time of inspection or the like.

In the printed circuit board according to the second aspect, in addition to the effect of the first aspect, the marking is a scale marking written at predetermined intervals on the basis of a specific lead. Therefore, marking can be easily marked on the circuit board even in a narrow place. In the printed circuit board according to the third aspect, in addition to the effects of the first or second aspect, the marking is printed on the printed circuit board by silk-screening, so that the marking can be performed easily and at low cost. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating an example of an electronic component mounted on a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a plan view showing another example of the present invention and showing an example of an electronic component mounted on a printed circuit board.

FIG. 3 is a plan view showing still another example of the present invention and showing an example of an electronic component mounted on a printed circuit board.

[Explanation of symbols]

 1 electronic component 3 lead 4 marking

Claims (3)

[Claims] 1. A printed circuit board on which electronic components having a large number of leads are mounted, on a portion of the circuit board on which the electronic components are mounted, a marking for facilitating identification of a number assigned to the lead. A printed circuit board characterized by the following. 2. The printed circuit board according to claim 1, wherein the marking is a scale marking written at predetermined intervals based on a specific lead. 3. The printed circuit board according to claim 1, wherein the marking is silk-printed on the printed circuit board.