JPH0265293A - Pattern on printed board for surface mounting - Google Patents

Abstract

PURPOSE:To obtain a surface mounting printed board pattern capable of preventing the positional shift of a chip component by a method wherein the corners of sides, which face each other, of a pair of electrode patterns are beveled by straight lines or curves. CONSTITUTION:Two corners of each of sides, facing each other, of a pair of electrode patterns 10a and 10b are cut out in straight line to be tapered. Therefore, the inner corners of the electrode patterns 10a and 10b are beveled by straight lines, so that the positional shift of the patterns 10a and 10b can be prevented at the soldering connection through a reflow system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application in Industry-1-) The present invention relates to an improvement in the wiring pattern of a printed circuit board on which surface-mounted chip components are mounted. .

(Prior art) With the miniaturization of various communication devices, electronic devices, etc., surface-mounted components with extremely small dimensions, commonly referred to as chip components, have recently been frequently used as components such as capacitors and resistors used in these devices. It has reached the point where

5(a) (bl and (c) are a plan view and a Δ-Δ cross-sectional view showing an example of the shape of a chip component, and a printed pattern for mounting and soldering these chip components, such as a chip The capacitor has a thin rectangular parallelepiped main body I, and an electrode part 2 connected to both ends of the main body!
The overall shape of the main body 1 and the electrode part 2 forms a thin straight J body.

When mounting such a chip component on a printed circuit board P''-, as shown in FIG. After mounting, it is common to heat and connect using the one-way solder connection method.

Also, it is possible to apply such chip parts to a burrito board.
The placement is often done using an automatic mounting device, but when soldering is finished, the opposing patterns 10, 10, and 10, as shown in FIG.
In addition to assimilating to the central part of (As shown in cl, many things solidify in a 1-downward state.) Each electrode part of the deep part is placed at the center of each electrode pattern (at an equal distance of 11 points from the side of the coat of each electrode part). (equidistant from each outer edge),
If such positional misalignment occurs, the soldering between the chip components and the pattern electrodes may become insufficient (), resulting in poor continuity or falling off of the components during use, which may result in equipment failure. 1. Although the cause of such misalignment is unclear, if the chip component is placed even slightly to the left, right, ], diagonally, etc. with respect to the pattern electrode 3, It is presumed that this is because an asybalance occurs in the distance between the peripheral edge of the electrode part 2 and the peripheral edge of each pattern electrode 3, and the surface tension of the melted solder becomes uneven, which causes the deviation to expand and continue to expand. 11 For example, in Figure 6 (at), if reflow is performed with the deep part placed slightly to the right before reflow, the gap between the right edge of the right electrode part 2 and the right edge of the right electrode S Since the distance 1)) is smaller than the distance 2 between the left electrode section 2 and the left electrode 3, the surface tension of the molten solder existing in the range of the distance 1 is greater than the distance 2 between the left electrode part 2 and the left electrode 3. It is inferred that this acts as a stronger pulling force, and assimilates the chip component in a state where it is pulled further to the right than when it is placed. .

It is thought that pattern deviations such as those shown in FIG. 6 (bl fcl) are often caused by deviations in the initial placement position expanding during the cooling and solidification process.

In addition to such deviations in the mounting position of the chip components, for example, due to inconsistencies in the quality of the solder 4 in each pattern, or inconsistencies in the assimilation speed of the molten solder on each pattern, It is thought that the surface tension may become unbalanced.

When a chip component is connected to the electrode button in such an abnormal position, the intervening solder cannot form the ideal fillet shape for solder connection.
As mentioned above, the electrical connection with the electrode pattern becomes incomplete.

Furthermore, misalignment in the mounting position or posture of chip components is a major obstacle to higher integration. .

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and it solves the problem of misalignment of chip components that tends to occur when soldering is performed by one-way reflow soldering by placing the electrode part of a gootube component on a pattern electrode. The purpose is to provide a printed circuit board pattern for surface mounting that can prevent this.

(Summary of the Invention) In order to achieve the object No. 14, the present invention provides a printed circuit board having a pair of rectangular electrode patterns each soldered to a pair of electrode portions of a chip component. It is characterized in that the corners of each opposing side are chamfered in a straight line or curve.

(Example) Hereinafter, the pattern for a printed board for surface mounting of the present invention will be explained in detail based on the example shown in the attached drawings. For clarity, the dimensions of the pattern 12 and the dimension ratio of the chip components are somewhat exaggerated, but in actual practice, the conventional dimension ratio may be used.

FIG. 1 is an explanatory diagram of a pattern according to a first embodiment of the present invention, in which two corner portions of each opposing side of a pair of electrode patterns 10a and lOb are cut out in a straight line shape to form a tapered shape. The structure is distinctive.

Figure 2(a) shows the electrode patterns lOa and 10b of Figure 1.
, J- shows a state in which the electrode portions 2.2 of the deep parts are connected by a reflow soldering method, and in this embodiment, the opposing inner sides of each electrode pattern IOa, IOb and the inner side of each electrode portion 2 The edges match, but in the same figure [
The =J'' method may be set so that the opposing inner sides of each electrode pattern lOa and Job are located further inward as shown in bl.

According to experiments conducted by the applicant, electrode patterns] Oa, lO
As a result of linearly chamfering the inner corners of b, it is possible to prevent the misalignment of each pattern shown in FIGS. 6(a), (b), and (c) during reflow soldering.
1. We were able to.

The main reason why such positional deviations can be prevented is that molten solder ( As a result of the surface tension on the chip component gradually increasing continuously along the chamfered taper portion, even if the depth component is initially placed with some deviation to the left or right, 1 degree downward, diagonally, etc., It is inferred that this is because the strong surface tension of this part acts to prevent further deviation1.Also, although the reason is not clear, the positional deviation during placement may cause the solder to cool and assimilate. We were also able to confirm that it had been corrected and moved to the proper central position.

FIG. 3 shows a second embodiment of the present invention, in which the electrode pattern I
Although this embodiment differs from the first embodiment in that the opposing sides of Oa and IOb are arranged in an arc shape, it has the same positional shift prevention effect as in the first embodiment.

FIG. 4 shows a third embodiment of the present invention, in which the electrode pattern I
This embodiment differs from the first embodiment in that each corner of the opposing sides of Oa and Job is curved and chamfered into a concave shape. On the contrary, each corner may be curved into a convex shape and chamfered.

In any of these examples, it was possible to obtain a one-minute positional shift prevention effect.

In this way, in the present invention, when the electrode portions at both ends of the chip component are reflow-soldered to a pair of opposing electrode patterns, the corners of the opposing sides of the electrode patterns are chamfered. Even if the initial mounting position of the chip component deviates from the predetermined central position, the positional deviation can be corrected or prevented from increasing during the process of cooling and solidifying the solder. .

(Effect of the invention) As described below, according to the present invention, there is provided a patterned electrode element.

It is possible to prevent positional displacement of the tip and tip parts that occurs when the electrode part of the dip part is placed on the reflow soldering method.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the structure of a pattern according to the first embodiment of the present invention, and FIG. An explanatory diagram showing the state, FIG. 2(b) is an explanatory diagram of the configuration of a modified example of the electrode pattern of FIG. 1, FIG. 3 is an explanatory diagram of the configuration of another embodiment of the present invention, and FIG. 5(a), 5(b) and 5(c) are explanatory diagrams of the configuration of another embodiment, and FIG. a) (b) and (c) are explanatory diagrams showing a state in which the chip/tube parts are misaligned. l... Chip component body 2... Electrode portions 2a, 2b.
...J side both sides 3...electrode pattern 4...solder] Oa, 10b
... Electrode pattern 20 ... Chamfered portion Patent applicant Toyo Tsushinki Co., Ltd.

Claims (3)

[Claims] (1) In a printed board having a pair of rectangular electrode patterns each soldered to a pair of electrode parts of a surface mount chip component, the corners of each opposing side of the pair of electrode patterns are chamfered. A surface mount printed board pattern featuring: (2) The pattern of a printed board for surface mounting according to claim 1, wherein the chamfered portion has a linear tapered shape. (3) A pattern of a printed board for surface mounting, characterized in that the chamfered portion has a non-linear curved shape.