Reverse taper, anti-pull out support feature for surface mount HDMI and USB connectors

A reverse tapered mounting tab for a signal connector is disclosed. The signal connector includes the reverse tapered mounting tab coupled to a connector body having a connector port inside. The reverse tapered mounting tab is configured to be secured in a through hole of a circuit board. Solder may be positioned in the through hole after positioning the mounting tab. The solder may prevent the mechanical tab from being forced through the through hole even after minor cracking and deformations in the solder.

BACKGROUND

1. Technical Field

Embodiments of the disclosure are directed to securing a signal connector to a circuit board and, in particular, to increasing the durability of a soldered connection between a tab of the signal connector and a through hole in the circuit board.

2. Description of the Related Art

In computing devices, such as personal computers, there are a number of ports that a user can access. These ports provide functionality to additional devices that communicate with the computing device, such as printers, webcams, music players, TVs, satellite set top boxes, and much more. The wear on these ports is greater when the users are coupling lines to and decoupling lines from the port. Wear is also increased by strain on the mechanical connector caused by the coupled line being in tension or compression.

Heat may also increase the wear as the connector may experience weakening from fatigue or may fail because of repeated thermal expansion and contraction cycles. As heat increases, the volume of matter tends to increase. Because there are different materials coupled together, their rates of expansion will vary. As heat cycles occur in the system, either as a result of normal operation, or from power cycling of the system, the different materials will expand and contract according to their coefficient of thermal expansion. Furthermore, larger areas will experience a greater overall expansion than smaller areas, so different sized pieces will not expand uniformly. The heat may be generated by the circuit board, the signal connector, or both.

Other factors may also increase the failure rate of the signal connectors as well. The effects of these factors are amplified when using surface mount signal connectors in which the connector uses through mount tabs for coupling and/or securing the connector to a circuit board and surface mount connectors for electrically coupling the signal lines to the circuit board. Many of these ports are viewed as system critical ports and a failure of the connector requires the system to be scrapped. This leads to user dissatisfaction and increased manufacturer warranty costs.

FIG. 1is an isometric view of an HDMI panel flange signal connector according to the prior art. The signal connector100includes a connector body102having an opening104. The opening104exposes a port connector106housed inside the connector body102. A panel flange108extends from the connector body102on a top side of the connector body102. A first mounting tab112and a second mounting tab110extend from the connector body102on a bottom side of the connector body102. The first and second mounting tabs112,110are straight tabs with uniform widths over the entire length of the each tab.

The port connector106will have a number of individual surface contact lines that extend from the under surface of the connector body, which cannot be seen in this view. These signal pads are coupled with a surface mount connection to a circuit board.

The first and second mounting tabs112,110are typically coupled to the circuit board using solder. There are two bonds with the solder in each connection, the first being a bond between the solder and the circuit board. The circuit board through hole is often lined with copper to increase the durability of this connection. These bonds will generally withstand up to 40 pounds in a linear shear force pull test. The second bond is the bond between the solder and the mounting tab.

The tab may be made of tin, nickel, another pure material, an alloy, or a plated material covered with any one of the previous materials. Tin provides good adhesion but poor resistance to cracking Nickel provides good resistance to cracking, but poor adhesion. An alloy or a plated material usually provides a better balance of material properties than either tin or nickel. This second solder bond, between the tab and the solder, is typically much weaker than the first bond due, in part, because of the less durable materials, but also because of a reduced surface area of the bond as compared to the through hole to solder bond.

Lead based solders generally provide a sufficiently durable connection between the circuit board and the signal connector. While lead based solder may be sufficiently durable, the industry continues to move away from lead based solder due to environmental and health concerns. Non-lead based solders suffer from a greater risk of cracking with use, reducing durability.

When the mounting tabs fail, the connector may fail either because of loss of electrical connection for the mounting tab or failure of surface contact lines. When the tabs fail they may lose good electrical connection with the circuit board. Often, the mechanical tabs are used to couple the signal connector to ground, and a loss of electrical connection means the signal connector is floating. This may result in a high current situation from charges accumulating either on the circuit board or on the signal connector. Other problems associated with an ungrounded circuit could also be present. In addition, when the tabs fail the mechanical loads on the connector may be transferred to the much weaker surface contact lines. When the surface contact lines are subject to these loads, they experience a reduced expected lifespan, leading to the whole signal connector failing earlier. A way to increase the useful life of these signal connectors is needed.

BRIEF SUMMARY

A reverse tapered mounting tab on a signal connector is disclosed that provides increased durability of the connection between the signal connector and a circuit board. Solder is positioned around the tapered mounting tab to create a compression fitting between the mounting tab and the circuit board that prevents the mounting tab from slipping out of the solder if the solder cracks or deforms.

A signal connector device according to one embodiment includes a connector body with a port connector inside the connector body, and a reverse tapered mounting tab. The reversed tapered mounting tab has three sections, a first section near the top, a second section near the middle and a third section near the bottom, the second section more narrow than the first and third sections. In a preferred embodiment the change in width between the sections is gradual, with the change in width between the third section and the second section being even more gradual than the change in width between the first section and the second section.

The signal connector with through mount tabs may have either surface mount or through mount contacts for the signal passing through the connector. The signal connector may also have a plurality of reverse tapered mounting tabs, and the plurality of reverse tapered mounting tabs may be in different sizes.

When mounted to the circuit board, the signal connector is preferably connected with the use of a solder connection coupling the reverse tapered mounting tab to a through hole of the circuit board. In one embodiment the top and bottom of the mounting tab are above and below the circuit board, respectively, and the tapered section lies within the circuit board through hole. In another embodiment, the tapered section extends beyond the through hole of the circuit board.

Also disclosed is a method for securing a signal connector to a circuit board by forming a reverse tapered mounting tab on the signal connector and soldering the reverse tapered mounting tab to the circuit board. A tapered section of the mounting tab may be completely encapsulated by the solder and the solder may extend beyond a top and bottom surface of the circuit board.

DETAILED DESCRIPTION

An HDMI surface mount connector is used in the figures for illustrative purposes only and should not be construed as a limitation of the claims. The disclosure is applicable to all signal connectors, including but not limited to: HDMI, USB, displayport, serial connectors, Ethernet ports, power connectors, audio jacks, FireWire, or any other signal connector. Additionally, the disclosure relates to both surface mount and through mount signal connectors.

FIG. 2is a side view of an HDMI panel flange signal connector with a reverse tapered mounting tab, according to one embodiment. The signal connector200includes a connector body202having an opening204. The opening204exposes a port connector housed inside the connector body202. A panel flange208extends from the connector body202, preferably on a top side of the connector body202. A first mounting tab212and a second mounting tab210extend from the connector body202, preferably on a bottom side of the connector body202. In other embodiments the signal connector200may not have a panel flange208. Also, the signal connector200may have only one mounting tab. A surface contact line214is coupled to the connector body202. The surface contact line214is electrically coupled to the port connector.

The first mounting tab212is a reverse tapered mechanical mounting tab. The first mounting tab212has a first section213, a third section219and a second section217that is a middle section positioned between the first and third sections213,219, respectively. The reverse taper is shown with the first mounting tab212having a narrow second section217having a second width216and having a wide third section219having a third width218. The second width216is measured at the most narrow region of the second section217of the first mounting tab212. The second section217is adjacent to the first section213and the connector body202. The third width218is measured at the widest point of the third section219of the first mounting tab212and is spaced away from the connector body202. The second section217, at its most narrow width, has a width that is less than the width of both the first section213and the third section219. The first section213may be the same width as the third section219. In some embodiments, the second section217may have a width that is slightly larger than the width of the first section213. In one embodiment, the second mounting tab210has an approximately constant width, while in other embodiments it is tapered in a fashion similar to the taper of the first mounting tab212.

FIG. 2depicts a first side of the signal connector200, with the first and second mounting tabs212,210. In one embodiment, a second side of the signal connector200opposite the first side may be a mirror image of the first side, including similarly sized and positioned mounting tabs. In another embodiment, the second side does not mirror the first side and may or may not include mounting tabs of various shapes and sizes.

FIG. 3is a diagrammatical side view of a reverse tapered mounting tab positioned in a circuit board, according to one embodiment. The first mounting tab212is positioned in a first through hole332of a circuit board330. The circuit board has a thickness334between a top surface336and a bottom surface338. The first mounting tab212is coupled to the circuit board330with a solder connection340. The solder of solder connection340completely fills the first through hole332and extends above the top surface336and the bottom surface338of the circuit board330.

The first mounting tab has a first section213above the second section217, the first section213having with a first width320measured at the first section213of the first mounting tab212closer to the top surface336than the bottom surface338of the circuit board330. The second width216is measured at the second section217of the first mounting tab212and is closer to the top surface336than the bottom surface338of the circuit board330. The third width218is measured at the third section219of the first mounting tab212closer to the bottom surface338than the top surface336of the circuit board330. The second width216of the first mounting tab212is smaller than both the first width320and the third width218. The third width218and the first width320may be the same width or different widths.

In a preferred embodiment the solder connection340extends beyond the top surface336and the bottom surface338of the circuit board330to sufficiently cover the first mounting tab212such that the first, second and third sections are all completely encapsulated in the solder of solder connection340.

In one embodiment, the thickness334of the circuit board330is approximately 1.6 millimeters and the second width216is measured at a point approximately 0.25 millimeters above the top surface336of the circuit board330.

The first mounting tab212has a first width profile between the second width216and the first width320and a second width profile between the second width216and the third width218. In a preferred embodiment, the first and second width profiles are approximately linear, meaning that the rate of change of the width is approximately constant. The degree of taper in the first width profile is a first taper angle324. The degree of taper in the second width profile is a second taper angle322. It is preferred that the first taper angle324is greater than the second taper angle322. It is also preferred that the second width profile extends over a greater distance than the first width profile. The second width profile may extend over at least the entire thickness334of the circuit board330, in one embodiment.

When the first mounting tab212is soldered in the through hole332, the larger third width218of the third section219prevents the first mounting tab212from being forced out of the through hole332. A constant width mounting tab would be more susceptible to being forced through as fatigue from heat and stress eventually deform or crack the solder connection340. A minor deformation or crack may loosen the solder connection of the straight tab enough to release the tab. A reverse tapered tab, like the one shown inFIG. 3, would continue to hold the signal connector200in place after the occurrence of minor cracking and deformation. The larger width of the first mounting tab212at the third section219cannot be forced through the smaller width of the solder340at the second section217, despite the solder of the solder connection340losing some or all of the surface friction against the first mounting tab212. Also, the larger width of the first mounting tab212at the first section213cannot be forced through the smaller width of the solder340at the second section217. Compression forces can hold the first mounting tab212in place when the surface friction coupling fails.

The first mounting tab212may also have a reverse taper in the thickness of the first mounting tab212in addition to or instead of reverse taper in the width of the first mounting tab212. The thickness would be greater at the first and third sections213,219of the first mounting tab212than at the second section217of the first mounting tab212. The narrow second section217would be fixed into position by the solder connection340in the through hole332of the circuit board330.

In a preferred embodiment the first mounting tab212is a ground line which couples the connector body202to a ground line of the circuit board330. In an alternate embodiment, the first mounting tab212is a blade type signal line configured to transmit signals between a port connector in the connector body202and a signal line on the circuit board330.

The reverse tapered first mounting tab212increases the durability of the interface between the signal connector200and the circuit board330. As a mating connector is repeatedly inserted into and removed from the signal connector200on the circuit board330, the first mounting tab212is subjected to mechanical stress. The stress may also come from the tension on a connector plugged into the signal connector200. In addition, heat, either from the transmission through the signal connector200or from the circuit board330, may cause fatigue in the solder connection340. These and other factors will lead to degradation of the integrity of the solder connection340.

As the solder connection340fatigues it may crack or deform. Because the first mounting tab212is shaped with a reverse taper, cracks and deformations will not cause the signal connector to be released from the circuit board330. Any cavities created in the solder connection340will only allow slight movement in the first mounting tab212as the wider portion of the first mounting tab212will be forced into any slightly enlarged openings in the solder connection340.

The same fatigue in the solder connection340is present when the solder connection340is enlarged due to stresses from repeated thermal expansion and contraction cycles. As the first mounting tab212creates cavities in the solder connection340due to heat cycles, the wider portions of the first mounting tab212will be forced into the slightly enlarged gap in the solder connection340as the first mounting tab212cools, allowing only limited movement and preventing the first mounting tab212from being released from the through hole332of the circuit board330.

Because of the reverse taper, heat cycles also reposition the first mounting tab212into the correct location when cavities have developed in the solder connection340. If cavities have developed and heat is applied, the first mounting tab212will attempt to expand. Because of the reverse taper shape, the first mounting tab212will be forced back to the most neutral point in which the narrowest point of the second section of the first mounting tab212is forced into the narrowest opening of the solder connection340.

In addition, because the reverse taper of the first mounting tab212causes the first mounting tab212to force itself into contact with the solder connection340, the electrical connection between the first mounting tab212and the solder connection340is maintained. The first mounting tab212may be the ground connection for the signal connector200in some embodiments to ensure that the ground voltage of the signal connector200does not float due to a bad ground connection. A floating ground voltage may lead to a high current short circuit, which may burn out a component, or may lead to a corrupted signal transmission that interferes with the signal transmitted through the signal connector200. The ground connection may be from the circuit board330to the signal connector200through the first mounting tab212and the solder connections340. The reverse tapered first mounting tab212may force itself into any cavities in the solder connection340from cracks or deformations to maintain a ground connection to the circuit board330.

FIG. 4ais an isometric view of an HDMI panel flange signal connector with a reverse tapered mounting tab positioned on a circuit board, according to one embodiment. The signal connector200has an opening204which exposes a port connector406housed inside the connector body202. The signal connector200is positioned on a top surface336of a circuit board330. The first mounting tab212extends through a first through hole332in the circuit board330. The second mounting tab210extends through a second through hole442in the circuit board330. The first and second mounting tabs212,210extend beyond a bottom surface338of the circuit board330. In a preferred embodiment, the first mounting tab212is a reverse tapered mechanical mounting tab as discussed above.

The first through hole332is used to secure the signal connector200to the circuit board330. It may be preferred to minimize the clearance between the first mounting tab212and the through hole332to ensure that the signal connector200is correctly aligned. This results in tight clearances between the first mounting tab212and the first through hole332that may be hard to position solder into. The connection between the solder connection340and the first mounting tab212is strengthened by a sufficiently complete solder fill of the first through hole332. As shown inFIG. 4a, the first through hole332may include a flow slot460that is a semi-cylindrical recess in the first through hole332running from the top surface336of the circuit board330to the bottom surface338. The flow slot460provides a low resistance path for the solder to flow into the first through hole332, while maintaining the narrow clearance between the first mounting tab212and the first through hole332at edges of a face of the first mounting tab212. This and other designs for improved solder flow may be used with respect to any through holes on the circuit board330.

The interface of the signal connector200to the circuit board330may benefit from increased overall durability. In one embodiment, the signal connector may experience an increased resistance to a first torque around a first axis through the first through hole332, the first axis orthogonal to a face of the first mounting tab212. In another embodiment, the signal connector may experience an increased resistance to a second torque around a second axis through the second through hole442, the second axis being orthogonal to a face of the second mounting tab210. For example, as a mating connector is repeatedly inserted into or removed from the signal connector200, a force will be generated on the signal connector200. The force vector may be approximately parallel to the top surface336of the circuit board330and approximately orthogonal to a face of the opening204. Because this force is generated at a distance from, and not in line with, the through holes332,442, a torque will be generated.

When a force is generated against the connector body202pointing towards a rear side of the signal connector200(e.g., inserting a mating connector into the connector body202), a torque will be generated in the first mounting tab212and the signal connector will attempt to rotate around the first axis because the mounting tabs cannot be forced towards the front side of the signal connector200due to the mounting tabs212,210being in the through holes332,442, respectively. The first torque around the first axis may be resisted primarily at the panel flange208with the aid of the second mounting tab210. In an alternate embodiment, the first torque creates a tension force on the second mounting tab212that is resisted by the reverse taper of a mounting tab in the second through hole442.

When a force is generated against the connector body202and pointing towards a front side of the signal connector200(e.g., removing a mating connector from the connector body202), a torque will be generated in the second mounting tab210and the signal connector200will attempt to rotate around the second axis because the mounting tabs cannot be forced towards the front side of the signal connector200due to the mounting tabs212,210being in the through holes332,442, respectively. The second torque around the second axis may be resisted primarily by the first mounting tab212. The addition of a reverse taper in the first mounting tab212provides the signal connector200with an increased resistance to the second torque. The second torque creates a tension force on the first mounting tab212that is resisted by the reverse taper of the first mounting tab212in the solder connection340.

FIG. 4bis an isometric view of the HDMI panel flange signal connector ofFIG. 4awith solder covering the mounting tabs. The signal connector200is shown mounted to the circuit board330by a solder connection340. The solder connection340is positioned in the first through hole332such that solder emerges from both the top surface336and the bottom surface338of the circuit board330. The solder connection340encapsulates the second section of the first mounting tab212. Solder may also secure the second mounting tab210in the second through hole442.

In one embodiment, the solder connection340completely encapsulates the first mounting tab212. In another embodiment, the solder connection340covers all of the second section217, and part of the first and third sections,213,219. Solder may also cover all or part of the second mounting tab210. In one embodiment the first and second mounting tabs212,210are secured to the circuit board330with individual solder connections. In a further embodiment, the first and second mounting tabs212,210are secured to the circuit board330with a single solder connection.

As shown, the signal connector200is preferably mounted on an edge of the circuit board330. However, the signal connector200may also be mounted on an interior location of the circuit board330.

FIG. 5is an isometric view of an HDMI port connector with two reverse tapered mounting tabs positioned on a circuit board, according to one embodiment. The signal connector500includes a connector body502having an opening504. The opening504exposes a port connector506housed inside the connector body502. A first mounting tab512and a second mounting tab544extend from the connector body502, preferably on a bottom side of the connector body502. The signal connector500is positioned on a top surface336of a circuit board330. The first mounting tab512extends through a first through hole532in the circuit board330. The second mounting tab544extends through a second through hole542. The first and second mounting tabs512,544may extend beyond a bottom surface338of the circuit board330.

Both the first mounting tab512and the second mounting tab544are reverse tapered mechanical mounting tabs. The reverse taper of the first mounting tab512and the second mounting tab544is similar to the taper described with respect to the first mounting tab212ofFIG. 2. This embodiment experiences a similar resistance to a second torque around a second axis through the second through hole542, the second axis orthogonal to a face of the second mounting tab544. The use of a reverse tapered second mounting tab544improves durability of the interface between the signal connector500and the circuit board330by increased resistance to a first torque around a first axis through the first through hole532and orthogonal to a face of the first mounting tab512. The first torque creates a tension force on the second mounting tab544that is resisted by the reverse taper of the second mounting tab544in the second through hole542.

In one embodiment, the two reverse tapered mounting tabs512,544may be used on a signal connector without a panel flange. In another embodiment the two reverse tapered mounting tabs512,544may be used in conjunction with a signal connector having a panel flange. In a further embodiment, a signal connector may include only one reverse tapered mounting tab, but neither a second reversed tapered mounting tab nor a panel flange.