JPH03228392A - Printed board - Google Patents

Abstract

PURPOSE:To easily recognize the first pin of an electronic component not only from a component mounting surface but also from a soldering surface by forming the shape of a pad for the first pin or a pad near the first pin different from the shape of a pad for other pin at both side surfaces of a printed board. CONSTITUTION:The shape of a pad 41 at a first pin insertion part 6 is formed in a square shape, and formed in a shape different from circular pads 4 at for another pin insertion parts 61, 61,.. The resist escape 51 around the pad 41 is similarly formed in a square shape to match it, and the pad 41 and the escape 51 are formed in a square shape not only on the component mounting surface but also on the soldering surface only at the first pin insertion part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed circuit board, and particularly to a printed circuit board suitable for mounting DIP type electronic components.

[Conventional technology]

Now, as an example, the mounting of electronic components of a 14-pin IC 74LS OO will be described. When looking at the direction of the IC so that the letters written on the package can be seen correctly, the lower left pin is pin 1. There is a semicircular depression on the left side of the IC package, which serves as a guide for the direction of the first pin.

As shown in FIG. 3, silk letters 1 and 74L indicating the IC name 7 4LS OO are printed on the component mounting surface of the conventional printed circuit board in the area where such electronic components are mounted.
A rectangular silk figure 2 indicating the package shape of SOO is printed on a silk screen, and a semicircle 2a is drawn on the short side of this silk figure 2. Also, outside @ of silk figure 2,
Fourteen holes 3 into which IC pins are inserted are provided, and circular pads 4 are provided around the holes 3 to form through holes. Further, around the band 4, there is also a circular resist relief 5. In addition, 6 in the figure is an IC
The part where pin 1 is inserted is shown.

Therefore, when mounting electronic components on a printed circuit board, the characters written on the package of the electronic component and the half circle of the package should be placed in the direction of the semicircle 2a of the silk letter 1 and silk figure 2 on the component mounting surface of the printed circuit board. The orientation of electronic components was determined by matching the circles.

[Problem to be solved by the invention]

With the above-described conventional technology, there is little potential for electronic components to be mounted on a printed circuit board in the wrong orientation. Additionally, the number 1 pin of electronic components can also be determined based on general practice.

However, since there is no mark for inserting the No. 1 pin, it may be confusing which hole 3 is for inserting the No. 1 pin or which pin is the No. 1 pin after mounting the electronic component. It is especially difficult to understand when viewed from the solder side, which is the back side of the component mounting surface. For example, when checking waveforms, it is sometimes necessary to select a specific pin from the solder surface, which is inconvenient.

Also, depending on the type of electronic component to be mounted, the package may not have a semicircular recess. The printed circuit board on which such electronic components are mounted does not have silk letters or semicircular silk figures, but only rectangular silk figures. Therefore, it was not possible to determine the orientation of the electronic component only from the silk stamp section 1, and there was a high probability that the electronic component would be mounted incorrectly.

An object of the present invention is to provide a printed circuit board in which the No. 1 pin of an electronic component can be easily identified not only from the component mounting surface but also from the soldering surface.

[Means to solve the problem]

In order to achieve the above object, the shape of the pad for the No. 1 pin of one electronic component or the pad close to the No. 1 pin is formed in a shape different from the shape of the pads for other pins on both surfaces of the printed circuit board.

[Effect]

The shape of the band for pin 1 or the pad close to pin 1 on the component mounting surface is different from the shape of the pads for other pins, so
The hole into which the No. 1 pin should be inserted can be determined at a glance. This prevents the electronic components from being oriented incorrectly during component mounting.

Further, since the shape of the pad for pin 1 or a pad close to pin 1 on the solder surface is different from the shape of the pads for other pins, pin 1 can be easily confirmed even after components are mounted. Therefore, when selecting a specific pin from the solder surface during a waveform check, the different pad shapes serve as landmarks and the work can be carried out smoothly.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Note that the same members and portions as in FIG. 3 are given the same reference numerals, and their explanations will be omitted. The shape of the pad 41 of the No. 1 pin insertion portion 6 is square, and the shape of the pad 41 of the No. 1 pin insertion portion 6 is square.
It is formed in a shape different from the circular pad 4 of . In accordance with this, the resist relief 51 around the pad 41 is also formed in a square shape. The pad 41 and the resist relief 51 are formed in a square shape not only on the component mounting surface but also on the soldering surface only at the portion where the No. 1 pin is inserted.

In this way, the shape of the pad 41 for the No. 1 pin is different from the shapes of the pads 4 for other pins, so that the hole 3 into which the No. 1 pin is to be inserted can be immediately determined at a glance.

This prevents the electronic components from being oriented incorrectly during component mounting. Furthermore, since the shape of the pad for pin 1 on the solder surface is different from the shape of the band for other pins, pin 1 can be easily confirmed even after the components are mounted. Therefore, even when selecting a specific pin from the solder surface during a waveform check, the square pad serves as a landmark and the work can be carried out smoothly.

By the way, a method of indicating the No. 1 pin insertion portion 6 with some kind of mark by silk printing may also be considered. This method poses no problem for printed circuit boards that are silk-printed on both sides. However, in most cases, only the component mounting surface is covered. In such a printed circuit board, the number 1 pin mark is printed using silk printing only on the component mounting surface. if,
If the number 1 pin mark is also applied to the solder surface, the manufacturing cost of the printed circuit board will increase. The mark for pin 1 on the solder side is not indispensable, but adding one more process to add the mark for pin 1 on the solder side increases the price of the printed circuit board. That's a problem.

It is also conceivable to leave a mark for pin 1 with a pattern instead of silk printing. This method is suitable for printed circuit boards with low-density wiring and a small number of parts.

However, in printed circuit boards with high-density wiring and a large number of parts, it is necessary to secure a certain amount of space so that the wiring pattern and the No. 1 pin mark do not come into contact with each other. In addition, the method of searching for gaps and inputting pin 1 marks for each component on both sides of the printed circuit board after completing the wiring pattern is too time-consuming and may lead to an increase in design time. .

In this regard, this embodiment does not leave a mark for pin 1 with silk or a pattern, but instead changes the shape of the pad 41 itself, so once the pad 41 is made, it can be copied repeatedly. Can be used. For this reason,
There is no additional process, no increase in unit cost, and no increase in design time.
A number pin mark can be applied.

FIG. 2 shows another embodiment of the present invention, showing a part where electronic components of a 10-pin module resistor are mounted.

The module resistor has a pin on the bottom surface of the package, and the package has a rectangular shape without a semicircular depression. Therefore, the silk figure 21 has a rectangular shape, and a hole 3, a band 4, and a resist relief 5 are provided inside the silk figure 21. Therefore, similarly to the embodiment described above, the pad 41 and resist relief 51 of the No. 1 pin insertion portion 6 are made square, and the other pin insertion portions 61, 62, and
. . are formed on both sides of the printed circuit board in a shape different from the circular pads 4 and resist reliefs 5.

In this case, although it is not possible to determine the orientation of the electronic component only from the silk pattern 21, it is possible to mount the electronic component in the correct orientation using the No. 1 pin mark indicated by the square pad 41. Furthermore, even after the component is mounted, the No. 1 pin of the electronic component can be determined from the solder surface of the printed circuit board.

In each of the above embodiments, the case where the pad 41 is square has been described, but the shape is not particularly limited as long as it can be distinguished from other pin insertion parts. Further, as in the embodiment, it is most preferable that the shape of the pad 41 of the first pin insertion part 6 is different from the pad 4 of the other pin insertion parts, but if the second pin insertion part 6 is close to the first pin insertion part 6. Portion 61 or No. 3 pin insertion portion 62 only, or No. 1 pin insertion portion 6 and No. 2 pin insertion portion 6
Even if both 1 and 1 are changed to a different shape from the other pin insertion parts, 1
The number pin insertion portion 6 and the number 1 pin can be determined.

〔Effect of the invention〕

According to the present invention, the first pin pad or the first pin of an electronic component
Since the shape of the pad close to the number pin is formed on both sides of the printed circuit board to be different from the shape of the pad for other pins, the following effects can be obtained.

The hole into which the No. 1 pin should be inserted can be immediately determined at a glance, and there is no need to make a mistake in the orientation of the electronic component when mounting the component. In addition, since the No. 1 pin can be easily confirmed even after the component is mounted, when selecting a specific pin from the solder surface during a waveform check, for example, the different pad shapes serve as landmarks and the work can be carried out smoothly. Furthermore, when applied to a multilayer printed circuit board, the different pad shapes can be used as a mark when inspecting the wiring of inner layer patterns.
Inspections can be carried out smoothly.

[Brief explanation of drawings]

The figures are views of a part of the printed circuit board as seen from the component mounting surface, and FIG. 1 is a front view showing one embodiment of the present invention, and FIG. FIG. 3 is a front view of the conventional example. 3...hole, 4.41...pad, 6...1
No. pin insertion part, 61.62... No. 2 and 3 pin insertion part.

Claims (1)

[Claims] 1. In a printed circuit board in which a hole is formed for inserting the pin of an electronic component and a pad is formed around this hole, the shape of the pad for pin 1 of the electronic component or the pad close to pin 1 is formed on both sides of the printed circuit board or A printed circuit board characterized in that the inner layer surface of the multilayer printed circuit board is formed in a shape different from that of other pin pads.