This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2011-050696, filed on Mar. 8, 2011, the entire contents of which are incorporated herein by reference.
The embodiment discussed herein is related to a surface-mount connector and a substrate unit.
Surface-mount connectors that connect terminals have been used in recent years.
The pin connector 101 includes an enclosure 1001 made of resin, such as a polyamide resin. The enclosure 1001 has an open-top hollow portion 1001a. Multiple electrically conductive pin terminals 1002, which protrude upward, are arranged in two rows inside the hollow portion 1001a. The pin terminals 1002 are made of a metal such as a nickel-base alloy or brass. A receptacle connector, which is not illustrated and which is to be fitted into the pin connector 101, is inserted from the open top, and thus the pin terminals 1002 of the pin connector 101 fit into multiple terminals of the receptacle connector. The pin connector 101 also includes lower terminals 1002a that penetrate through a bottom portion of the enclosure 1001 and are then bent sideways.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
Next, how to mount the pin connector 101 on a substrate will be described.
As illustrated in
As illustrated in
The substrate 102, however, is not completely flat, and is somewhat warped.
When the surface-mount pin connector 101 is placed on a substrate that is warped as described above, some lower terminals 1002a may fail to come into direct contact with the corresponding electrically conductive patterns 1021 of the substrate 102, as illustrated in
However, so-called coreless substrates, even of a large size, have been used in response to a demand for thin substrates to reduce the weight and the cost of built-in components. Unlike a substrate containing a core material that retains a predetermined level or higher of surface flatness as a result of the strength of the core material, a coreless substrate that does not contain a core material has low strength and thus is warped easily.
As illustrated in
A conceivable countermeasure against this problem is to increase the amount of material in the soldering paste portions 1022 to be applied and thus make larger balls out of the melted soldering paste portions 1022. However, increasing the amount of material in the soldering paste portions to be melted may lead to joining (short-circuiting) of adjacent electrically conductive patterns even if a solder resist is applied to the surface of the substrate 102. Thus, the increase in the amount of material in the soldering paste portions to be applied is subjected to a certain limit.
A pin connector illustrated in
As illustrated in
When the connector 101 is fastened in this manner, the coil springs 1002f each expand or contract so as to follow the warpage of the substrate 102 and thus all the lower terminals 1002a come into contact with the electrically conductive patterns on the substrate 102, as illustrated in
Japanese Laid-open Patent Publication No. 2006-294308 describes an example of the related art.
According to an aspect of the invention, a surface-mount connector includes an enclosure, and a plurality of terminals that is mounted in the enclosure, one end of each of terminals being joined to a surface of a substrate, another end of each terminal fitting into a terminal of a connector that is to be fitted into the surface-mount connector, wherein each of the terminals is mounted in the enclosure so as to be movable within a restricted range in directions to come into contact with and separate from the substrate.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
The use of the pin connector 101 described above involves a space being secured on the substrate 102 for installing the lock mechanisms 103 near to where the connector 101 is mounted. As described above, it is preferable that the lock mechanisms 103 be tightly fastened to the substrate 102 since the lock mechanisms 103 generate such a force as to press the connector 101 against the substrate and to thus fix the connector 101 to the substrate. For this reason, the lock mechanisms 103 are often mounted on the substrate 102 with lock screws inserted from the back surface of the substrate 102 into through holes formed in the substrate 102. For this reason, spaces for the screws and the through holes have to be secured on the back surface of the substrate 102 in addition to the spaces for the lock mechanisms 103 on the front surface of the substrate 102. Thus, the area available for wires and the flexibility of arrangement of wiring are reduced. Forming through holes in a multilayer substrate, in particular, puts limitations on all the layers in terms of the area available for wires and the flexibility of arrangement of wiring.
In view of the above problems, the present disclosure is made to provide a surface-mount connector that imposes fewer limitations on wiring and that copes with the warpage of a substrate.
The pin connector 1 includes an enclosure 11 that has an open-top hollow portion 11a. Multiple pin terminals 12, which protrude upward, are arranged in two rows inside the hollow portion 11a. A receptacle connector, which is not illustrated and which is to be fitted into the pin connector 1, is inserted into the pin connector 1 from the open top, and thus the pin terminals 12 of the pin connector 1 fit into multiple terminals of the receptacle connector. The pin connector 1 also includes lower terminals 12a that penetrate through a bottom portion of the enclosure 11 and are bent sideward.
As illustrated in
As illustrated in
As illustrated in
In the embodiment, the inner diameter D1 of each first cylindrical hole 11c1 is set at 0.5 mm, the diameter D3 of the first cylindrical portion 12c of each pin terminal 12 and the diameter D5 of the lower terminal 12a of each pin terminal 12 are set at 0.4 mm, the inner diameter D2 of each second cylindrical hole 11c2 is set at 0.8 mm, and the diameter D4 of each second cylindrical portion 12d is set at 0.7 mm.
The height H2 of the second cylindrical portion 12d of each pin terminal 12 is smaller than the height H1 of each second cylindrical hole 11c2.
In the embodiment, the height H2 of the second cylindrical portion 12d of each pin terminal 12 is set at 0.3 mm and the height H1 of each second cylindrical hole 11c2 is set at 0.65 mm.
As illustrated in
The retaining board 13 includes a backbone portion 13a that is to be interposed between the rows of the pin terminals 12 and multiple arm portions 13b that are to be interposed between adjacent pin terminals 12.
Adjacent arm portions 13b of the retaining board 13 are separated from each other by a gap with a width D7. The width D7 is larger than the diameter D5 of the lower terminal 12a of each pin terminal 12 but smaller than the diameter D4 of each second cylindrical portion 12d (set at 0.5 mm, in the embodiment). Accordingly, when one pin terminal 12 is moved downward, the lower side of the second cylindrical portion 12d comes into contact with the upper sides of the arm portions 13b and thus the pin terminal 12 is restrained from being moved further downward.
As has been described with reference to
The diameter D3 of the first cylindrical portions 12c and the diameter D5 of the lower terminals 12a of the pin terminals 12 are smaller than the inner diameter of the first cylindrical holes 11c1 used for housing, and the diameter D4 of the second cylindrical portions 12d of the pin terminals 12 is smaller than the inner diameter of the second cylindrical holes 11c2 used for housing. Thus, each pin terminal 12 is held while having a small contact resistance with the first cylindrical portion 11c1, the second cylindrical portion 11c2, and the arm portions of the retaining board 13.
In the above structure, each pin terminal 12 is held so as to be vertically (in directions indicated by arrow E of
Next, how to mount the pin connector 1 on the substrate 2 will be described.
As illustrated in
As illustrated in
Referring now to the sectional view of
As described above, the pin terminals 12 in the pin connector 1 are vertically movable before being placed on the substrate 2. When the pin connector 1 is placed on the substrate 2, an upper end of the second cylindrical portion 12d of each of the pin terminals 12 that come into contact with the electrically conductive patterns 21 positioned in or around the tops of the warped substrate (the electrically conductive patterns 21 located in regions 31 and 32 in
Other pin terminals 12 are vertically movable by a distance L. Thus, as illustrated in
Nevertheless, each pin terminal 12 is only movable within the range of the above distance L. For this reason, a region (regions K1 and K2 in
Referring to
For convenience, pin terminals 12 illustrated in
In accordance with the reference numerals 12-1 to 12-4 denoting the pin terminals, the components of the pin terminals 12-1 to 12-4 are denoted by reference numerals that correspond to those described from
In addition, the second cylindrical holes 11c2 and the first cylindrical holes 11c1 that house the second cylindrical portion 12d-1 to 12d-4 of the pin terminal 12-1 to 12-4 and that are formed in the bottom plate 11b of the enclosure 11 will also be denoted by reference numerals appended by “-1” to “-4” in order from the left.
The electrically conductive patterns 21 that are brought into contact with the lower terminals 12a-1 to 12a-4 of the pin terminals 12-1 to 12-4 will also be denoted by reference numerals appended by “-1” to “-4” in order from the left.
As described above, the pin terminal 12-1 positioned in or around the top of the warped substrate 2 is held at the highest position within the movable range in the enclosure 1. The pin terminals 12-2 and 12-3 descend within the range of the distance L and thus come into contact with the electrically conductive patterns 21-2 and 21-3. On the other hand, the lower terminal 12a-4 of the pin terminal 12-4 fails to come into contact with the corresponding electrically conductive pattern 21-4, even when the lower side of the second cylindrical portion 12d-4 comes into contact with the arm portions 13b of the retaining board 13 (the distance between the lower end of the lower terminal 12a-4 and the electrically conductive pattern 21-4 at this time is denoted by D8).
As described above, however, the lower terminals 12a-1 to 12a-4 and the electrically conductive patterns 21-1 to 21-4 are respectively joined to one another by soldering. As described above, joining is performed by applying the electrically conductive patterns with soldering paste and then heating the substrate 2. The soldering paste melts and liquefies when heated. Generally, a thermosetting epoxy resin coating called a solder resist is applied to the surface of the substrate 2 except for at to-be-soldered regions. Since the solder resist repels melted solder, the solder resist keeps the soldering paste from adhering to regions other than the to-be-soldered regions and thus keeps adjacent electrically conductive patterns 21-1 to 21-4 from being short-circuited due to the melting of the soldering paste portions 22.
In
When the soldering paste portions 22-1 to 22-4 are melted in this state, the soldering paste portions 22-1 to 22-4 form balls on the respective electrically conductive patterns 22-1 to 22-4 as illustrated in
Referring now to
As illustrated in
As a result, the pin terminal 12′ on the far most right has a gap D9 between the lower terminal 12a′ and the corresponding electrically conductive pattern 21′, which is larger than the gap D8 of the embodiment between the lower terminal 12a-4 and the electrically conductive pattern 21-4.
In the embodiment, it has been described that the soldering paste portions 22 used for joining form balls, and thus enable joining despite the presence of a gap of a certain size. However, the size of the balls is limited. Thus, joining would fail if the gap were excessively large, as in the case of the pin terminal 12′ on the far most right in
Thus, with the pin connector 1 according to the embodiment, the pin terminals 12 are reliably joined to the corresponding electrically conductive patterns formed on the considerably warped substrate, which do not allow the electrically conductive patterns thereon to be joined to the fixed pin terminals 12′ of the related art.
The pin connector 1 according to the embodiment has a structure in which the pin terminals 12 are simply made to be movable vertically. Since the pin terminals 12 descend along the warped substrate 2 due to gravity, the pin connector 1 copes with the warpage of the substrate 2. Thus, the pin connector 1 according to the embodiment does not have to use lock mechanisms for pressing the enclosure 11 of the pin connector 1 down toward the substrate, as in the known pin terminals including springs. Since the use of the pin connector 1 does not involve a space being secured on the substrate 2 for the lock mechanism, components and wiring patterns on the substrate 2 are allowed to be arranged with more flexibility.
In the embodiment, the difference between the diameter of the first cylindrical portion 12c of each pin terminal 12 and the inner diameter of each first cylindrical hole 11c1 and the difference between the diameter of the second cylindrical portion 12d of each pin terminal 12 and the inner diameter of each second cylindrical hole 11c2 are specified. These differences are determined in such a manner that the pin terminal 12 is vertically movable and that each pin terminal 12 is allowed to tilt to such an extent that the pin terminal 12 fits into the receptacle connector that fits into the pin connector 1. In other words, the above differences between the diameters and the inner diameters may be of any size, other than those specified in the embodiment, with which the pin terminal 12 is made vertically movable and with which each pin terminal 12 is allowed to tilt to such an extent that the pin terminal 12 fits into the receptacle connector that fits into the pin connector 1.
Moreover, the difference between the height of the second cylindrical portion 12d of each pin terminal 12 and the height of each second cylindrical hole 11c2 of the bottom plate 11b, that is, the vertically movable distance of each pin terminal 12 may be set as appropriate, depending on the size of the pin connector 1, the average amount of warpage of the substrate 2, or the like.
In the pin connector 1 according to the embodiment, the lower terminals 12a are vertically movable in response to changes in shape of the warped substrate 2 even after being joined to the electrically conductive patterns 21 by soldering. Accordingly, even when the shape of the warped substrate changes over time or due to relocation, the pin terminals 12 move vertically so as to follow the change. Thus, the solder is less likely to become detached from the pin connector with the change in shape of a warped substrate than in the case of the pin connector that includes the fixed pin terminals 12.
A pin connector has been described as an example in the embodiment, but the embodiment is also applicable to other surface-mount connectors including a receptacle connector.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment of the present invention has been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
Number | Date | Country | Kind |
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2011-050696 | Mar 2011 | JP | national |