JP2004296306A - Connector for surface mounting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connector for surface mounting which will not fall off from the substrate in a reflow soldering process, even when the connector is on an underface side of a printed circuit board in a second reflow. <P>SOLUTION: In a connector 6 for the surface mounting provided with a plurality of surface mounting terminals 7, a terminal 8 penetrating through the substrate, and a base 9 composed of insulating resin for housing and holding one end of both terminals 7, 8, and mounted on the printed circuit board 4 by means of the reflow soldering, both terminals 7, 8 are constituted of a shape memory alloy to memorize a normal shape at the temperature in the reflow soldering, and the base 9 is inhibited from being thermally deformed as both terminals 7, 8 keep the normal shape in the reflow soldering. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface mount connector, and more particularly, to a surface mount connector mounted on a surface of a printed circuit board by reflow soldering.
[0002]
[Prior art]
The surface mounting connector usually includes a terminal portion made of a copper alloy or the like and a base made of a resin insulator for holding the terminal portion. When mounting this surface mounting connector on the surface of a printed circuit board (hereinafter abbreviated as a substrate) by reflow soldering (hereinafter abbreviated as a reflow), the base may be deformed because it is exposed to a high temperature in a reflow process. Conventional surface mount connectors that take this measure include, for example, an insulator (base) having a component holding portion for holding an electronic component and a plurality of electronic components having one end held by the component holding portion of the insulator. A plurality of contacts (terminals) correspondingly connected to the contacts and the other end corresponding to a plurality of pads of the mounting board by soldering, and an insulator for preventing deformation of the insulator in a reflow process on the mounting board. And an insulator deformation preventing member which is held and fixed at a predetermined portion. Further, as a deformation preventing member, a shape memory alloy that maintains a straightly extended shape in a temperature range from a solder melting temperature to a temperature at which solder is solidified in a reflow process is used (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2000-173683 (page 2, FIG. 1)
[0004]
[Problems to be solved by the invention]
Since the conventional surface mount connector is configured as described above, a deformation preventing member is required to prevent deformation of the base during reflow. Also, in a small electric device such as a cellular phone, it is necessary to mount components on both sides of the board at a high density in order to reduce the size. However, after reflowing one side of the board (1st reflow), the board is turned upside down. In the case where the surface is reflowed (2nd reflow), the surface mounting connector often comes to the lower surface of the substrate in the 2nd reflow process for convenience of mounting. FIG. 7 is a side sectional view when a conventional surface mount connector having a second reflow process is mounted on a substrate. (A) shows the time of the first reflow, and (b) shows the time of the second reflow. As shown in FIG. 1A, a surface mounting connector including terminals 1 and 2 and a base 3 is mounted at a predetermined position on a substrate 4, and the terminal 1 is aligned with the solder surface, and the terminal 2 is passed through the through hole 5 to make a first connection. Perform reflow. Next, the substrate 4 is turned upside down and 2nd reflow is performed. However, since the solder is melted by the heat of the reflow, it is necessary to design so that the surface mounting connector does not drop from the substrate 4 due to gravity. That is, it is necessary to design the solder contact area of the terminal such that (weight of the surface mount connector) <(solder surface tension generated at the solder contact portion of the terminal).
[0005]
When the base 3 is thermally deformed as shown in FIG. 7A by the heat of the reflow, the coplanarity (flatness) of the terminal 1 changes, and the solder contact area of the terminal 1 decreases. When the deformation is large and the solder contact area is insufficient, the surface mounting connector may fall off due to its weight in the second reflow step as shown in FIG. 7B.
[0006]
As such a countermeasure against falling off of the surface mounting connector in the second reflow process, measures such as application of an adhesive or use of a high-temperature solder at the time of the first reflow and use of a low-temperature solder at the time of the second reflow can be considered. This also increases costs in terms of equipment, materials and management. For example, in the mounting work of a large and heavy I / O connector, SIM connector, or the like, such as a mobile phone, prevention of falling off in the second reflow process has been a major issue.
[0007]
The present invention has been made in order to solve the above-described problems, and to provide a surface mounting connector that suppresses a reduction in a contact area between a terminal and a solder portion due to thermal deformation of a base in a reflow process. With the goal.
[0008]
[Means for Solving the Problems]
A surface mounting connector according to the present invention includes a plurality of conductive terminals and a base made of an insulating resin for housing and holding one end of the terminal, and is mounted on a printed circuit board by reflow soldering. In a surface mount connector, the terminals are made of a shape memory alloy that stores the correct shape at the temperature at the time of reflow soldering, and the base is thermally deformed by the force that the terminals try to maintain the correct shape at the time of reflow soldering It is intended to prevent this.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
1 and 2 are views showing a process of mounting the surface mounting connector according to the first embodiment of the present invention on a substrate. FIG. 1 shows the first reflow and FIG. 2 shows the second reflow. FIG. 1 (a) is a plan view and FIG. 1 (b) is a side view showing a partial cross section. In the drawing, a surface mounting connector 6 includes a plurality of conductive terminals including a surface mounting terminal 7 and a through-substrate terminal 8 and a base 9 made of an insulating resin for storing and holding one end of these terminals. And is mounted on the substrate 4 and mounted by reflow. As a material of the base 9, a resin such as PPS or LCP is used according to characteristics such as strength required for the base 9. The surface-mounting terminals 7 and the through-substrate terminals 8 are made of a shape memory alloy that stores a proper shape at a temperature during reflow. Here, the regular shape is a shape as originally designed without deformation or distortion.
[0010]
FIG. 3 is a sectional view showing an example of the inside of the surface mounting connector. As shown in the figure, the surface mount terminals 7 and the through-substrate terminals 8 are also intricate inside the base 9 and are configured as if they were skeletons.
[0011]
First, the first reflow process will be described. A solder paste 10 is printed on a portion of the substrate 4 corresponding to the surface mounting terminal 7 and a peripheral portion of the through hole 5 through which the substrate through terminal 8 penetrates. The terminal 7 and the board end terminal 8 are soldered to the board 4, and the surface mount connector 6 is mounted on the board 4. At this time, the solder also melts and enters the through hole 5 into which the board through terminal 8 is inserted.
[0012]
At the time of reflow, high-temperature heat is applied to the entire surface mounting connector 6, and the base 9 tends to be deformed by this heat. On the other hand, since the surface-mounting terminals 7 and the through-substrate terminals 8 use a shape memory alloy that stores a normal shape at the temperature at the time of reflow, the shape is tried to be maintained by applying heat. As described above, since each terminal is entangled inside the base like a skeleton, it is necessary to prevent the base 9 from being thermally deformed by the force of the surface mount terminal 7 and the substrate penetrating terminal 8 to maintain a regular shape. Block. Further, the coplanarity of the soldering surface is maintained by maintaining the regular shape of the surface mounting terminal 7.
[0013]
Next, in the second reflow process, as shown in FIG. 2, the substrate 4 is turned over, and the surface mounting connector 6 is on the lower surface side of the substrate 4. Since the base 9 is not deformed and the coplanarity of the terminal portion is maintained, the solder contact area of the surface mount terminal 7 and the through-substrate terminal 8 is ensured, and the surface mount connector 6 has a (weight of the surface mount connector) < (Solder surface tension generated at the contact portion between the surface mounting terminal and the substrate penetrating terminal and the substrate) can be maintained.
[0014]
As described above, according to the invention according to the present embodiment, the surface-mounting terminals and the through-substrate terminals, which are the terminals of the surface-mounting connector, are formed of a shape memory alloy, so as to prevent thermal deformation of the base during reflow. Therefore, a predetermined contact area between the terminal and the solder can be ensured, so that the surface mounting connector can be prevented from dropping off the substrate during the second reflow.
[0015]
Embodiment 2 FIG.
FIG. 4 is a side sectional view showing a process of mounting the surface mounting connector according to the second embodiment of the present invention on a substrate. (A) shows the time of the first reflow, and (b) shows the time of the second reflow. In the figure, reference numerals 4, 5, 7, and 9 are the same as those in FIG. The through-substrate terminal 12 of the surface-mount connector 11 in the present embodiment is made of a shape memory alloy, and the portion outside the base 9 at normal temperature penetrates the through-hole 5 of the substrate 4, for example, as shown in FIG. A straight line shape as shown by a dotted line is stored, and a shape that does not penetrate through hole 5 at the temperature at the time of reflow, for example, an L shape as shown in the figure is stored. The portion of the through-substrate terminal 12 buried inside the base 9 and the surface-mounting terminal 7 store a regular shape at the temperature during reflow.
[0016]
Next, the operation will be described. As shown in FIG. 4A, at the time of the first reflow, the substrate through terminal 12 of the surface mount connector 11 becomes L-shaped at that temperature when the heat of the reflow is applied, and the front end is locked to the substrate 4. You. At the time of the second reflow, the board 4 is turned upside down and the surface mounting connector 11 is on the back side of the board as shown in (b), but since the board through terminal 12 is locked to the board 4, the surface mounting connector 11 is locked. 11 does not fall off the substrate.
[0017]
As described above, according to the invention according to the present embodiment, the through-substrate terminal is made of a shape memory alloy that does not penetrate through-holes at the temperature at the time of reflow, for example, stores an L-shape. In addition, it is possible to reliably prevent the surface mounting connector from dropping off the substrate at the time of the second reflow, and to improve the mounting reliability.
[0018]
In the above description, the case where the terminal portion buried in the base 9 keeps a regular shape at the temperature at the time of reflow has been described. If the shape that penetrates and does not penetrate through hole 5 at the temperature at the time of reflow is stored, an effect of preventing the surface mount connector from falling off at the time of the second reflow can be obtained.
[0019]
Also, the memory shape of the through-substrate terminal 12 at the reflow temperature may be an acute L-shape as shown in FIG. 5 instead of the 90-degree L-shape. In this case, since a force for pressing the base 9 against the substrate 4 acts, the surface mounting connector 11 can be mounted in close contact with the substrate 4.
[0020]
Embodiment 3 FIG.
FIG. 6 is a side sectional view showing a case where the surface mounting connector according to the third embodiment is mounted on a substrate. In the figure, reference numerals 4, 7 to 9 are the same as those of FIG. The base 9 of the surface mounting connector 13 is provided with a connector fixing member 15 that penetrates through the through hole 14 provided in the substrate 4 and engages with the substrate 4. It is formed of a shape memory alloy that stores a shape that does not penetrate through hole 14 at the temperature at the time of reflow, for example, an L-shape as shown in the figure.
[0021]
Therefore, even if the board 4 is turned upside down at the time of the second reflow and the surface mounting connector 13 is on the lower surface side of the board, the connector fixing member 15 is hooked on the board 4, so that the surface mounting connector 13 may fall off the board 4. Absent. The number of the connector fixing members 15 may be one or three or more. Further, the through-substrate terminal 8 may have a shape as described in FIG. 4 of the second embodiment.
[0022]
According to the third embodiment of the present invention, the surface mounting connector is provided with the connector fixing member that locks to the board at the time of reflow. Since the connector fixing member can be arranged at a position where it can be effectively suppressed, the deformation of the base can be efficiently prevented in addition to the effects of the first and second embodiments.
[0023]
【The invention's effect】
As described above, according to the present invention, since the terminals of the surface mount connector are made of the shape memory alloy that stores the proper shape at the temperature at the time of reflow, the terminals try to hold the proper shape at the time of reflow. Thermal deformation of the base can be prevented by the force, and a predetermined contact area between the terminal and the solder can be secured.
[Brief description of the drawings]
FIG. 1 is a diagram showing a state at the time of a first reflow when a surface mounting connector according to a first embodiment of the present invention is mounted on a substrate.
FIG. 2 is a diagram showing a state at the time of 2st reflow when the surface mounting connector according to Embodiment 1 of the present invention is mounted on a board.
FIG. 3 is a sectional view of the surface mount connector according to the first embodiment of the present invention;
FIG. 4 is a side sectional view showing a case where a surface mounting connector according to Embodiment 2 of the present invention is mounted on a board.
FIG. 5 is a side sectional view showing another example of mounting the surface mounting connector according to the second embodiment of the present invention on a substrate.
FIG. 6 is a side sectional view showing a case where a connector for surface mounting according to a third embodiment of the present invention is mounted on a substrate.
FIG. 7 is a side sectional view showing a case where a conventional surface mounting connector is mounted on a substrate.
[Explanation of symbols]
4 Board 5 Through Holes 6, 11, 13 Surface Mount Connector 7 Surface Mount Terminal 8, 12 Board Through Terminal 9 Base 15 Connector Fixing Member.

Claims (4)

A plurality of conductive terminals, and a base made of an insulating resin for housing and holding one end of the terminal, a surface mounting connector mounted on a printed circuit board by reflow soldering,
The terminal is made of a shape memory alloy that stores a proper shape at the temperature at the time of the reflow soldering, and the base is thermally deformed by a force of the terminal to hold the shape at the time of the reflow soldering. A surface mount connector characterized by blocking. A plurality of conductive terminals, and a base made of an insulating resin for housing and holding one end of the terminal, a surface mounting connector mounted on a printed circuit board by reflow soldering,
The terminal comprises a surface mount terminal connected to the wiring on the front surface of the printed circuit board, and a through-board terminal connected to the wiring on the back surface through the through-hole of the printed circuit board. A surface mounting connector comprising a shape memory alloy that stores a shape that penetrates and does not penetrate the through hole at the temperature at the time of the reflow soldering. 3. The surface mounting connector according to claim 2, wherein the through-substrate terminal has a linear shape at normal temperature and stores an L-shape at the temperature during the reflow soldering. 4. The surface mounting connector according to claim 1, wherein a shape that penetrates a through hole provided in the printed board at normal temperature and does not penetrate the through hole at a temperature at the time of reflow soldering is stored. A connector for surface mounting, wherein a connector fixing member made of a shape memory alloy is provided on the base.

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