JPH06104559A - Printed board - Google Patents

Abstract

PURPOSE:To provide a printed board, being formed by arranging rectangular lands corresponding to the leads of a surface mounting component in matrix, in which auxiliary lands can deal with various components having different number of leads at the time of extension of circuit. CONSTITUTION:Leads 3 of a predetermined component 2, having lands 4 and auxiliary lands 5 corresponding to a plurality of leads 3 of the component 2, are bonded to the lands 4 and when the component 2 is additionally provided, leads 3 of the additional component 2 are bonded to the auxiliary lands 5 thus surface mounting the component 2. Rectangular auxiliary lands 5 having width corresponding to that of the lead 3 of the component 2 are arranged in a specified region of the printed board 1 in matrix at a first pitch 6 corresponding to that of the lead 3 of the component in lateral direction and at a second pitch 7 corresponding to the opposing distance of the lead 3 of a component 2, where the leads 3 on the opposite side faces have minimum opposing distance, in longitudinal direction.

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 components are surface-mounted, and more particularly to a printed circuit board in which quadrangular lands corresponding to leads are formed in rows and columns.

Recently, the adoption of SMT (Surface Mount Technology) on printed circuit boards of electronic devices has become active, but the mounting technology of SMT components does not follow this and when the addition of a circuit occurs. , SMT components are adhered to a printed circuit board and connected by strap lines to form a circuit, which is easy to peel off due to impact, etc. It is low and a method of solving this is desired.

[0003]

2. Description of the Related Art A conventional method will be described below with reference to FIGS. The same reference numerals denote the same objects throughout the drawings. Figure 9
As shown in FIG. 3, when a component (for example, an integrated circuit: IC) 2a is mounted on a printed circuit board (hereinafter referred to as a substrate) 1a, a plurality of leads 3a aligned on opposite side surfaces of the component 2a are provided on the substrate 1a. Solder to land 4a. The details will be described below.

As shown in FIG. 10, a plurality of rectangular lands 4a corresponding to the leads 3a of the component 2a are arranged side by side on the substrate 1a, for example, at a pitch of 1.27 mm so as to face both sides of the component 2a. Is formed. Such lands 4a are provided at positions corresponding to the components 2a to be mounted, and are connected to a circuit pattern (not shown).

Although not shown on the land 4a on the substrate 1a, a solder paste pattern is printed in advance, and the leads 3a of the component 2a are placed along the land 4a and heated in a steam atmosphere to be soldered. The circuit of the printed board unit is constructed by melting and soldering the paste pattern.

As a countermeasure for adding the component 2a by changing the circuit design at the time of trial production of this printed board unit, 16 pins (the number of the leads 3a is 16) which are relatively frequently used are mounted on the substrate 1a. , Part 2a) of FIG. 9 for an equivalent IC,
Or just to provide a spare land for 2-pin parts,
There is no area allowance for providing a wide variety of spare lands corresponding to all the components 2a on the substrate 1a.

Therefore, normally, as shown in FIG.
The lower surface of the substrate 1a is bonded to the substrate 1a with an adhesive, and the leads 3a of the other component 2a are connected by soldering with the strap wire S.

[0008]

According to the above conventional method, when a component is added by changing the circuit, the component is adhered to the substrate and then the lead wire is soldered to the lead to deal with the impact. As a result, there is a problem that the adhesive is easily peeled off, the parts move, and there is a high probability that the soldering portion of the strap wire will be broken due to the influence of vibration and the like, and the reliability is low.

It is an object of the present invention to provide a printed circuit board which can accommodate components with a minimum number of leads and a maximum number of leads when a circuit is added.

[0010]

FIG. 1 shows the principle of the present invention. In the figure, 1 is a printed circuit board, 2 is a component, 3 is a lead, 4 is a land, 6 is a first pitch, 7 is a second pitch, 5 is provided in a predetermined region of the printed circuit board 1, and a lead of the component 2 is provided. A square preliminary land having a width corresponding to the width dimension of 3, a lateral pitch of the preliminary land 5 and a first pitch corresponding to the pitch of the leads 3 of the component 2, and a vertical direction of the preliminary land 5. The lead 3 on the opposite side surface is the second bitch corresponding to the facing distance of the lead 3 of the component 2 having the minimum facing distance at the pitch of.

Therefore, the component 2 whose mounting has been decided in advance
When the component 3 is joined to the land 4 and the component 2 is added, the lead 3 of the component 2 to be added is joined to the preliminary land 5 to surface-mount the component 2.

[0012]

When the lead 3 of the component 2 which is predetermined to be mounted is joined to the land 4 and the component 2 is added by a design change, the lead 3 of the component 2 to be added has the first pitch 6 in the lateral direction. By contacting and joining a plurality of rectangular preliminary lands 5 formed with the second pitch 7 in the vertical direction, each lead 3 can be formed even in the component 2 in which the pitch of the leads 3 and the facing distance of the leads 3 are different. Since the spare lands 5 are always joined to each other, the spare lands 5 can be mounted corresponding to the various components 2 between the component 2 having the largest number of leads and the component 2 having the smallest number of leads.

Therefore, it is possible to easily cope with design changes and the like, and by joining the individual leads 3 to the spare lands 5, the fixing of the component 2 can be ensured, and as in the conventional method,
Since it is not necessary to bond the component 2 to the printed board 1, the risk of disconnection failure due to the peeling of the bond and the movement of the component 2 is eliminated, and the reliability can be improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 is a block diagram showing an embodiment of the present invention,
FIG. 3 is an explanatory view showing an example of mounting various parts on the spare land. The same reference numerals denote the same objects throughout the drawings.

The pitch P1 and the pitch P2 in FIG. 2 correspond to the first pitch 6 and the second pitch 7 in FIG. 1, respectively.
As shown in FIG. 2, the substrate 1a is provided with a plurality of lands 4a and a plurality of preliminary lands 5a. The spare land 5a is provided in a spare land area A surrounded by a broken line in the figure, and has a plurality of rectangles (for example, width = 0.65 mm, length = 1.27) corresponding to the size of the lead 3a of the 16-pin component 2a. mm),
Pitch P1 corresponding to the pitch of the lead 3a of the 16-pin component 2a (common to each manufacturer for compatibility)
Bitch P2 corresponding to the facing distance of the lead 3a of (for example 1.27 mm) and the vertical direction of 3 pins (3 leads 3a on each side)
The blocks are arranged in a matrix (for example, 2.54 mm).

With such a structure, the component 2a, which is predetermined to be mounted on the land 4a, is mounted by the method described in the conventional example as shown by the chain double-dashed line in the figure. When additionally mounting the component 2a, the component 2a is mounted by using the spare land 5a.

That is, even in a component 2a having different pitches of the leads 3a and facing distances of the leads 3a, the leads 3a are always joined to the spare lands 5a which are separated from each other. Parts with 2a
Can be flexibly implemented.

As shown in FIG. 8, the mounted component 2a is connected to the lead 3a of another component 2a or the like by a strap wire S to form a circuit. FIGS. 3 (a) to 3 (c) show an example in which the component 2a having a different number of leads 3a is mounted on the block of the spare land 5a, and corresponding to each lead 3a of the component 2a having 16 pins to 2 pins. The additional component 2a can be mounted on the block of the spare land 5a.

FIG. 4 shows another embodiment (1). Figure 4
2 differs from the embodiment described with reference to FIG. 2 in that rectangular preliminary lands are arranged alternately in the vertical and horizontal directions. That is, as shown in the figure, the spare land 5b is provided in the spare land region B of the substrate 1c. The size of the spare land 5b is the same as that of the embodiment described with reference to FIG. 2, and the pitch P1 is set in the vertical direction.
(E.g. 1.27mm), and arrange them vertically and horizontally,
Also in the horizontal direction, the vertical and horizontal directions are alternately arranged, and the horizontal pitch of the auxiliary land 5b in the horizontal direction is twice the pitch P1.
(For example, 2.54 mm), the center lines of the auxiliary lands 5b in the horizontal direction and the center lines of the auxiliary lands 5b in the vertical direction are aligned as shown in the figure.

Since it has such a structure, FIG.
As shown in (c), the additional component 2a can be mounted on the block of the spare land 5b corresponding to each lead 3a of the component 2a of 16 pins to 2 pins.

In this case, the number of the lands 5b is smaller than that of the above-described embodiment, and the same purpose can be achieved. Further, as shown in the case of the modified 4-pin in FIG. It is also possible to correspond to the component 2a. In addition, since the distance between the lands 5b is made wider in the vertical direction than in the case of the embodiment, there is an advantage that the occurrence of short circuit can be reduced.

FIG. 6 shows another embodiment (2). Figure 6
Are different from the embodiment described in FIGS. 2 and 4 (1)
The difference is that the preliminary lands are arranged as squares in the vertical and horizontal directions.

That is, as shown in the figure, the spare land 5c is provided in the spare land region C of the substrate 1d. Spare land
The size of 5c is a square having a size corresponding to the size of the lead 3a of the 16-pin component 3a (for example, one side is 0.65 mm), and the horizontal and vertical directions have the same pitch P1 (as in the embodiment described in FIG. 2). For example, 1.27 mm) is formed in a block in which a plurality of blocks are arranged.

With this structure, as shown in FIGS. 7 (a) and 7 (b), the additional component 2a is used as a spare land corresponding to each lead 3a of the component 2a having 16 to 2 pins. It can be mounted on the block of 5c, and as shown in (c), it can also be applied to the case of mounting a quat flat package (QFP) having leads 3a on the four side surfaces.

In this way, by providing the blocks of the spare lands 5a to 5c in the spare land regions A to C of the substrates 1b to 1d, even if the component 2a having different lead 3a pitches and lead 3a facing distances is used, 3 is always a spare land 5a
Since it is joined to ~ 5c, parts 2a from 16 pins to 2 pins
Can be mounted using the spare lands 5a to 5c, and it is possible to flexibly cope with mounting when adding components. Therefore, as shown in FIG. 8, it is not necessary to bond the component 2a to the boards 1b to 1d, the leads 3a of the component 2a can be fixed to the preliminary lands 5a to 5c by soldering, and the strap wire S is used as the preliminary land. Since the solder is surely soldered to the leads 5a to 5c and the lead 3a, there is no fear that the adhesive will be peeled off to cause a disconnection failure due to the vibration of the component 2a unlike the conventional method, and reliability can be improved.

[0026]

As described above, according to the present invention, according to the first aspect of the present invention, the spare lands are mounted corresponding to various parts from the part having the largest number of leads to the part having the smallest number of leads. Therefore, it is possible to flexibly deal with the addition of parts such as design changes, and it is possible to fix the parts with the spare land, and the soldering of the strap wire to the lead is reliably performed. It is not necessary to bond the component to the printed board, the risk of disconnection failure due to vibration of the component due to peeling of the bond is eliminated, and reliability can be improved.

According to the second aspect, it is possible to cope with mounting of a deformable part having a special lead arrangement position. Claim 3
Then, it is possible to support QFP implementation. There is an effect.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an example.

FIG. 4 is a configuration diagram showing a different embodiment (1).

FIG. 5 is an explanatory diagram of a different embodiment (1).

FIG. 6 is a configuration diagram showing a different embodiment (2).

FIG. 7 is an explanatory diagram of a different embodiment (2).

[Fig. 8] Fig. 8 is an explanatory view of mounting the embodiment and different embodiments (1) and (2).

FIG. 9 is a perspective view illustrating a board on which components are mounted.

FIG. 10 is a plan view illustrating a land.

FIG. 11 is an explanatory diagram illustrating a conventional method.

[Explanation of symbols]

1,1a-1c are printed circuit boards (boards) 2.2a
Are parts, 3,3a are leads, 4,4a are lands,
5, 5a to 5c are preliminary lands, 6 is the first pitch, 7
Is the second pitch, P1, P2 is the pitch,

Claims (3)

[Claims] 1. The component (2) has a land (4) corresponding to a plurality of leads (3) and a spare land (5), and the lead (3) of the component (2) which is predetermined to be mounted is mounted. When the component (2) is joined to the land (4), the lead (3) of the component (2) to be added is joined to the spare land (5) to surface-mount the component (2). A printed circuit board, wherein the lead of the component (2) is placed in a predetermined area of the printed circuit board (1).
Rectangular backup land with a width corresponding to the width dimension of (3)
(5) is the lead with the first pitch (6) corresponding to the pitch of the leads (3) of the component (2) in the horizontal direction and the opposite side in the vertical direction.
A printed circuit board characterized in that (3) is formed by forming a matrix with a second bitch (7) corresponding to the facing distance of the lead (3) of the component (2) having the minimum facing distance. 2. The spare lands (5) are arranged vertically and alternately at the second pitch (7) in the vertical direction, and the horizontal pitch of the horizontal spare lands (5) is set to the second pitch (7). 2 times the pitch of 1 pitch (6) and a sideways spare land (5)
2. The printed circuit board according to claim 1, wherein the printed circuit board is formed by arranging the center lines of the same so as to coincide with the center lines of the vertically oriented preliminary lands (5). 3. A plurality of square spare lands (5) each having a size corresponding to the width dimension of the lead (3) of the component (2) are arranged in rows and columns at the first pitch (6). The printed circuit board according to claim 1, which is formed.