JP2006332492A - Printed-circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed-circuit board having a high positioning accuracy with a self alignment function without lowering a general versatility, and capable of providing a solder wettability to a peripheral circumference of a connecting terminal of an electronic element with its movement restricted. <P>SOLUTION: The printed-circuit board 10 is provided with a land 12 for mounting with the connecting terminal 15 of the electronic element 11 press contacted and mounted on the surface of an insulating material. The land 12 for mounting comprises two land parts 20 for mounting symmetrical to a central axis line A. Each of the land parts 20 for mounting has a narrow portion N with its width size narrowest on an identical line R perpendicular to the central axis line A, and both the narrow portions N provide the mounting position of the connecting terminal 15 so that the peripheral circumference portion 19 of the connecting terminal portion 15 is superimposed on the orthogonal line R. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed circuit board having a mounting land on which a connection terminal of an electric element is mounted in surface contact.

2. Description of the Related Art Conventionally, a printed circuit board on which an electronic element is mounted is known in which a mounting land on which a connection terminal of the electronic element is in surface contact is provided. This printed circuit board uses a self-alignment function that automatically corrects the position by the surface tension of the molten solder when mounting electronic elements, eliminating the slight misalignment between the connection terminals and the mounting land. ing. In this printed board, it has been proposed that the mounting land is formed in a circular shape or a rectangular shape, and one or a plurality of indentations are provided on the outer periphery thereof. In this mounting land, the movement of the electronic element by the self-alignment function can be limited to a position where each recess comes into contact with the peripheral edge of the connection terminal. The strength can be increased (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 10-317756 (page 2-6, FIG. 2)

  However, in this printed circuit board, the movement of the electronic elements in the normal direction of each depression is limited at a position where each depression contacts the peripheral edge of the connection terminal. For example, the shape of the mounting land is square. If there are four depressions at the center of each side of the outer periphery, and four depressions are formed at positions that are 90 degrees apart from each other on the outer circumference, the electron is obtained by sandwiching the two depressions facing each other. It is necessary to limit the movement of the element. In this way, since it is necessary to provide a recess so as to surround the connection terminal of the electronic element to be mounted, the position and dimensions of the mounting land and each recess are mounted in order to increase the positioning accuracy by the self-alignment function. If it is adapted to the shape and mounting position of the connection terminal of the electronic device to be used, the versatility will be lowered.

  In addition, since the solder cannot be wetted up to the peripheral portion where movement is restricted by each depression, for example, an electronic element having a connection terminal having a rectangular contact surface and rising from one side thereof is provided. In the case of mounting, the solder cannot be wetted on the rising surface and cannot be mounted properly.

  The present invention has been made in view of the above circumstances, and has a high positioning accuracy by the self-alignment function without reducing versatility, and the peripheral portion of the connection terminal of the electronic element whose movement is restricted. It is an object of the present invention to provide a printed circuit board that can cause solder wetting.

  In order to solve the above-described problem, the printed circuit board according to claim 1 is a printed circuit board provided with a mounting land on which a connection terminal of an electronic element is mounted in surface contact with a surface of an insulating material, The mounting land includes two mounting land portions that are symmetric with respect to the central axis, and each mounting land has a narrow portion having a narrowest width dimension on the same line orthogonal to the central axis. The narrow portions define a mounting position of the connection terminal so that a peripheral portion of the connection terminal overlaps the orthogonal line.

  The printed circuit board according to claim 2 is the printed circuit board according to claim 1, wherein the narrow portion is formed by a recess that forms a pair on the orthogonal line so as to straddle the orthogonal line. To do.

  A printed circuit board according to a third aspect is the printed circuit board according to the first or second aspect, wherein each of the mounting land portions has the narrowed portion at each of both end portions viewed in the extending direction. It is provided.

  In the printed circuit board according to claim 1, when mounting an electronic element having a pair of connection terminals, the movement of the connection terminals by the self-alignment function is caused by the narrow portion of the mounting land corresponding to each of the connection terminals. It can restrict | limit in the position where a peripheral part and an orthogonal line overlap. In addition, since the narrow portion provided in each mounting land portion that is symmetric with respect to the central axis is located on the same perpendicular line, a pair of connection terminals can be aligned on the same line, and the electronic device is appropriately It can be made a proper posture. Furthermore, since the positioning is performed by the narrow portion, the solder can be placed on the mounting land portion at a position facing the narrow portion, so that the solder can be wetted to the positioned peripheral portion.

  In the printed circuit board according to the second aspect, since the narrow portion is formed by a pair of recesses, the narrow portion can be easily and accurately provided.

  In the printed circuit board according to the third aspect, the connection terminals can be positioned at the peripheral portions at both ends thereof, and the solder can be wetted on both peripheral portions.

  According to the present invention, when mounting an electronic device having a pair of connection terminals, the movement of the connection terminals by the self-alignment function is performed perpendicularly to the peripheral portion of each connection terminal by the narrow portion of the corresponding mounting land portion. It is possible to limit the position where the line overlaps. In addition, since the narrow portion provided in each mounting land portion that is symmetric with respect to the central axis is located on the same perpendicular line, a pair of connection terminals can be aligned on the same line, and the electronic element can be aligned. Appropriate posture can be achieved. Thus, the positioning accuracy by the self-alignment function can be improved without providing a recess so as to surround the shape of the connection terminal of the electronic element to be mounted at a position that matches the shape of the mounting land. , Can increase versatility.

  Furthermore, since the positioning is performed by the narrow portion, the solder can be placed on the mounting land portion at a position facing the narrow portion, so that the solder can be wetted to the positioned peripheral portion. For this reason, when an electronic device having a connection terminal that rises from the positioned peripheral edge portion is mounted, it can be mounted appropriately by wetting the solder onto its rising surface.

  Embodiments of a printed circuit board according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view schematically showing a printed circuit board 10 and an electronic element 11 mounted thereon according to the present invention.

  The printed board 10 has a plate shape made of an insulating material, and a mounting land 12 is provided on the surface thereof. The mounting land 12 is a thin film made of a conductive material, and is disposed on the printed board 10 where the electronic element 11 is mounted. The mounting land 12 enables energization of the electronic element 11 fixed thereon.

  In this embodiment, the electronic element 11 is a chip LED, and includes a main body 13 and a connection terminal 15. The main body 13 has a rectangular parallelepiped shape in which a recess 13a is formed at the center so that the longitudinal cross-sectional shape is a U-shape (see FIG. 2). The main body 13 is provided with an emission portion 14 on a front surface 13b facing the recess 13a. The emission part 14 has a light source (not shown) on the inside thereof, and emits light emitted from the light source 14 in a direction V perpendicular to the front surface 13b. Electricity is supplied from the connection terminal 15 to the light source of the emission portion 14.

  The connection terminal 15 is made of a conductive material, and has two connection terminal plates 16 that are equal to each other as shown in FIG. Both connection terminal plates 16 have a long plate shape, and are extended in parallel to the emission direction V from the emission portion 14 so as to maintain a constant distance from each other. Although not shown in the drawing, the two connection terminal plates 16 are electrically connected to the light source of the emission portion 14. As shown in FIG. 2, both connection terminal plates 16 have a bottom surface portion 17 and a rising portion 18 that are continuous with each other. The bottom surface portion 17 extends along the bottom surface 13 c of the main body portion 13 and can come into surface contact with the mounting land 12. The rising portion 18 rises from one end edge portion 19 located on the recess 13 a side of the main body portion 13 when viewed in the extending direction of the bottom surface portion 17 in the peripheral edge portion defining the bottom surface portion 17. The rising portion 18 is folded back into the recess 13 a so that the tip portion thereof follows the main body portion 13. The electronic element 11 is mounted on the printed circuit board 10 with its connection terminals 15 fixed to the mounting lands 12 by reflow soldering.

  In the printed circuit board 10 of the present embodiment, the mounting land 12 has the following shape. As shown in FIG. 4, the mounting land 12 includes two mounting land portions 20 having the same shape. Both mounting land portions 20 are formed in a rectangular shape, and extend parallel to each other at positions symmetrical to the central axis A. The dimensions of both mounting land portions 20 and the distance between them are appropriately set according to both connection terminal plates 16 of the electronic element 11 to be mounted.

  Each mounting land 20 is formed with a pair of recesses 21. Each recess 21 straddles the same orthogonal line R orthogonal to the central axis A at both side edge portions 20 a of both mounting land portions 20. In the present embodiment, the orthogonal line R is set at a position biased toward the one end 20b side of the both mounting land portions 20, and each recess 21 is an intersection of the side edge portions 20a of each mounting land portion 20 and the orthogonal line R. It is defined by a semicircle with a center on top. Due to the recesses 21, the narrow portions N whose width dimension is the narrowest are formed on the orthogonal line R in the mounting land portions 20. Each of the recesses 21 only needs to form a narrow portion N on the same orthogonal line orthogonal to the central axis A in each of the mounting land portions 20 that make a pair, and the shape and position thereof are the same as in this embodiment. It is not limited to.

  Both mounting land portions 20 are partitioned by a narrow portion N into a terminal installation portion 22 and a solder placement portion 23. Each terminal installation portion 22 is a portion that comes into surface contact with the bottom surface portion 17 of each connection terminal plate 16 of the connection terminal 15 when the electronic element 11 is mounted. The solder placement portion 23 is a place where only the melted solder is placed without contacting the connection terminal plates 16 when the electronic element 11 is mounted.

  An electronic element 11 is mounted on the printed circuit board 10 by reflow soldering. In this method, before the solder is melted, the electronic element 11 has the rising portions 18 of the two connection terminal plates 16 positioned on the solder mounting portion 23 side, and the bottom surface portions 17 of the two connection terminal plates 16 are terminal-installed. It arrange | positions so that it may mutually oppose above the part 22 (refer FIG. 1 arrow O). Thereafter, the electronic element 11 is moved to an appropriate mounting position on the mounting land 12 by the surface tension of the melted solder, that is, the position is automatically corrected and positioned by the self-alignment function. The movement of the electronic element 11 by this self-alignment function is limited by the narrow portion N. That is, the bottom surface portion 17 of each connection terminal plate 16 of the connection terminal 15 is opposed to the narrow portion N facing each other by the surface tension of the molten solder placed above the mounting land portions 20. Is positioned at a position where the one end edge portions 19 coincide with each other. For this reason, the electronic element 11 is in a posture in which the emission direction V coincides with the direction of the central axis A of the both terminal installation portions 22 of the mounting land 12. Further, the electronic element 11 is positioned in the direction along the orthogonal line R so that the center line along the emission direction V coincides with the center axis A of the both terminal installation portions 22 of the mounting land. Furthermore, as shown in FIG. 5, the solder of the solder mounting portion 23 is wetted on the rising portions 18 of the connection terminal plates 16 of the connection terminals 15 (see reference numeral S). Therefore, in the printed circuit board 10, each end edge portion 19 of the connection terminal 15 coincides with each narrow portion N, the emission direction V of the electronic element 11 coincides with the direction of the central axis A, and the rising portion 18 by reflow soldering. The electronic element 11 can be mounted in a state in which the solder wets over the solder placement portion 23, that is, a fillet is formed.

In the printed circuit board 10, the following effects can be obtained.
(1) When the electronic element 11 is mounted by reflow soldering, one end edge portion 19 of each connection terminal 15 is formed by the narrow portion N of the mounting land portion 20 corresponding to each connection terminal plate 16 by the self-alignment function. And the perpendicular line R can be positioned, and the emission direction V of the electronic element 11 and the direction of the central axis A can be made to coincide with each other. Therefore, it has high positioning accuracy by the self-alignment function, and the electronic element 11 can be mounted in a desired posture on an appropriate mounting position on the mounting land 12. This is particularly effective when the electronic element 11 whose emission direction V changes depending on the mounting position and the posture in that state as in this embodiment.
(2) Since it is not necessary to provide the recess 21 so as to surround the shape of the connection terminal 15 of the electronic element 11 to be mounted at a position that matches the shape of the mounting land 12, it has high versatility. Yes.
(3) Since the positioning is performed by the narrow portion N, the solder on the solder placement portion 23 can be wetted to the positioned one end edge portion 19, and thus the connection terminal 15 having the rising portion 18 is formed. Even the electronic element 11 can be appropriately mounted by reflow soldering. That is, since the solder can be continuously attached from the bottom surface portion 17 to the rising portion 18 of the connection terminal 15, the connection terminal 15 is appropriately mounted on the printed circuit board 10 in a state of being fixed to the mounting land 12 by the solder. be able to.
(4) Since the narrow portion N is formed by the pair of recesses 21, the narrow portion N can be easily provided at an appropriate position.
(5) Since the fillet is formed on the mounted electronic element 11 from the rising portion 18 to the solder placement portion 23 (see S in FIG. 5), the electronic element is observed by observing the fillet. The state of soldering 11 can be easily confirmed from the outside.

  Actually, the mounting lands 12 having the dimensions shown below are formed corresponding to the electronic elements 11 having the connection terminals 15 having the dimensions shown below and mounted by reflow soldering. Each end edge portion 19 coincides with each narrow portion N, the emission direction V of the electronic element 11 coincides with the direction of the central axis A, and a fillet extending from the rising portion 18 to the solder placement portion 23 is formed. I was able to.

  As shown in FIG. 3, the connection terminal 15 of the electronic element 11 has a width dimension Y1 of 3.64 mm, a width dimension Y2 of each connection terminal plate 16 of the connection terminal 15 is 1.1 mm, and each connection terminal. The interval Y3 between the plates 16 is 1.44 mm, and the length dimension X of the connection terminal 15 is 2.85 mm.

  As shown in FIG. 4, the mounting land 12 has a width dimension W1 of 3.6 mm, a width dimension W2 of each mounting land 20 of the mounting land 12 is 1.2 mm, and each mounting land 20 The distance W3 is 1.2 mm, the length L1 of each mounting land 20 is 3.5 mm, and the length L2 of the terminal installation portion 22 of each mounting land 20 is 3.0 mm.

  Each mounting land 20 has a narrowed portion N only on one end 20b side, but can also be provided on the other end 20c (see FIG. 4) side.

  In the printed circuit board 10, when the electronic element 11 is mounted by reflow soldering, a force directed toward the solder placement portion 23 along the central axis A direction acts on each connection terminal plate 16 due to surface tension. It is conceivable that the movement of each connection terminal plate 16 due to the urging force is restricted by the narrow portion N. From this point of view, each mounting land portion 20 has a width dimension smaller than one end edge portion 19 of each connection terminal plate 16 of the electronic element 11 on which the narrow portion N is mounted, and the terminal installation portion 22 is mounted. It is desirable to have a length dimension substantially equal to the bottom surface portion 17 of each connection terminal plate 16 of the electronic element 11.

It is the perspective view which showed typically the printed circuit board which concerns on this invention, and the electronic device mounted thereon. It is a side view of the electronic device of FIG. It is a bottom view of the electronic device of FIG. It is a top view which shows the land for mounting provided in the printed circuit board. It is a side view which shows the state in which the electronic element was mounted in the printed circuit board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printed circuit board 11 Electronic element 12 Mounting land 15 Connection terminal 19 One end edge part 19 (as a peripheral part of a connection terminal)
20 Mounting land 21 Recess A Center axis N Narrow part R Orthogonal line

Claims (3)

A printed circuit board provided with a mounting land on which the connection terminal of the electronic element is mounted in contact with the surface of the insulating material,
The mounting land includes two mounting land portions that are symmetric with respect to the central axis, and each mounting land has a narrow portion having a narrowest width dimension on the same line orthogonal to the central axis. The narrowed portions define a mounting position of the connection terminal so that a peripheral portion of the connection terminal overlaps the orthogonal line.   The printed circuit board according to claim 1, wherein the narrow portion is formed by a recess that forms a pair on the orthogonal line so as to straddle the orthogonal line. 3. The printed circuit board according to claim 1, wherein each of the mounting land portions is provided with the narrowed portion at each of both end portions viewed in the extending direction. 4.

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