PADDLE CARD AND METHOD FOR MANUFACTURING THE SAME, AND ELECTRICAL CONNECTOR HAVING THE PADDLE CARD
20220385010 · 2022-12-01
Assignee
Inventors
Cpc classification
H01R24/60
ELECTRICITY
International classification
Abstract
A miniaturized paddle card assembly that provides high-speed, high-performance transmission. The paddle card has two or more rows of contact pads for mating with complementary conductors, two or more rows of terminals for cable termination, and alternating dielectric layers and metal layers. The two or more rows of terminals are disposed on respective metal layers. Such a configuration enables conductive traces electrically connecting corresponding contact pads and terminals to be substantially straight, and therefore reduces the lengths of the conductive traces. It is also reduced that the size of the paddle card in both a lateral direction parallel to the rows and a longitudinal direction perpendicular to the lateral direction, without changing the thickness of the paddle card. With the paddle card assembly provided herein, the integrity of the signals transmitted therethrough can be maintained and/or improved at higher speed.
Claims
1. A paddle card, comprising: a first surface comprising a first row of terminals for connection to a cable conductor and spaced from a centerline of the paddle card by a first distance; and a second surface facing a same direction as the first surface and spaced from the centerline of the paddle card by a second distance different from the first distance, the second surface comprising a second row of terminals for connection to a cable conductor.
2. The paddle card of claim 1, wherein: the first surface comprises contact pads coupled through the paddle card to the first row of terminals of the first surface and the second row of terminals of the second surface.
3. The paddle card of claim 1, comprising: a plurality of conductive traces electrically connecting the contact pads of the first surface to the first row of terminals of the first surface and the second row of terminals of the second surface.
4. The paddle card of claim 3, wherein: the plurality of conductive traces comprise pairs of conductive traces for transmitting differential signals, and the conductive traces of each pair have equal lengths.
5. The paddle card of claim 3, wherein: each of the plurality of conductive traces comprises a first contact end, a second contact end and an intermediate portion between the first contact end and the second contact end, the first contact end is electrically connected to a contact pad, the second contact end is electrically connected to a terminal, and the intermediate portion is straight.
6. The paddle card of claim 3, wherein each of the plurality of conductive traces is straight along at least 85% of its length.
7. The paddle card of claim 6, wherein angles between straight portions of the plurality of conductive traces and the centerline are within a range of −10 degrees to 10 degrees.
8. The paddle card of claim 3, comprising: a plurality of metal layers, wherein the plurality of conductive traces are distributed in the plurality of metal layers.
9. The paddle card of claim 1, wherein: the contact pads of the first surface comprise a first row of contact pads and a second row of contact pads disposed closer to the first row of terminals, and the contact pads in the second row of contact pads are electrically connected to respective terminals in the first row of terminals.
10. The paddle card of claim 3, wherein the plurality of conductive traces comprise a conductive trace electrically connecting a contact pad and a terminal that are aligned to each other.
11. A paddle card, comprising: a main body comprising a plurality of dielectric layers and a plurality of metal layers disposed on respective ones of the plurality of dielectric layers; and a first plurality of rows of contact pads and a second plurality of rows of terminals, the first plurality of rows of contact pads and the second plurality of rows of terminals disposed on two opposite ends of the main body, respectively, wherein: the second plurality of rows of terminals are on respective metal layers of the plurality of metal layers.
12. The paddle card of claim 11, wherein the plurality of metal layers comprise: a plurality of conductive traces connecting the first plurality of rows of contact pads to the second plurality of rows of terminals.
13. The paddle card of claim 12, wherein: the plurality of conductive traces comprise pairs of conductive traces for transmitting differential signals, and conductive traces of each pair of conductive traces have equal lengths.
14. The paddle card of claim 12, wherein each of the plurality of conductive traces is straight along at least 85% of its length.
15. The paddle card of claim 11, wherein: the first plurality of rows of contact pads are coupled through the paddle card to the second plurality of rows of terminals.
16. A cable assembly, comprising: a paddle card comprising: a leading edge, a trailing edge spaced from the trailing edge in a longitudinal direction, a plurality of contact pads comprising a first row of contact pads along the leading edge and a second row of contact pads spaced from the first row in the longitudinal direction, and a plurality of terminals comprising a third row of terminals along the trailing edge and a fourth row of terminals spaced from the third row in a direction opposite the longitudinal direction; a first plurality of cables electrically connected to terminals in the third row; and a second plurality of cables electrically connected to terminals in the fourth row.
17. The cable assembly of claim 16, wherein: the third row of terminals is offset from the fourth row of terminals in a transitional direction perpendicular to the longitudinal direction.
18. The cable assembly of claim 16, wherein: the plurality of terminals comprise a fifth row of terminals along the trailing edge and a sixth row of terminals spaced from the fifth row in the direction opposite the longitudinal direction, the paddle card comprises a plurality of metal layers, and the third, fourth, fifth, and sixth rows of terminals are disposed on different ones of the plurality of metal layers.
19. The cable assembly of claim 18, comprising: a third plurality of cables electrically connected to terminals in the fifth row; and a fourth plurality of cables electrically connected to terminals in the sixth row.
20. The cable assembly of claim 16, comprising: a housing at least partially enclosing the paddle card.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0053] The following accompanying drawings of the present disclosure are used here as a part of the present disclosure for understanding the present disclosure. The embodiments and their descriptions of the present disclosure are illustrated in the accompanying drawings to explain the principle of the present disclosure. The accompanying drawings are not intended to be drawn to scale. In the drawings:
[0054]
[0055]
[0056]
[0057]
[0058]
[0059]
[0060]
[0061]
[0062]
[0063]
[0064]
[0065] The accompanying drawings include the following reference numerals:
[0066] 1. plug electrical connector; 10. paddle card; 11. gold finger; 12. terminal; 13. conductive trace; 100. paddle card; 200. base body; 210. first end; 220. second end; 221. stair-step; 310. contact pad; 320. terminal; 400. conductive trace; 410. first connecting end; 420. second connecting end; 430. intermediate section; 500. cable; 600, 600′. housing assembly; 710. dielectric layer; 720. patterned metal layer; 730. conductive through-hole; 740. centerline; 750. first surface; 760. second surface; 770. first row of terminals; 780. second row of terminals; 800. mating electrical connector.
DETAILED DESCRIPTION
[0067] The inventors have recognized and appreciated designs for paddle cards assemblies that may be used in cable assemblies to support high-speed, high-performance transmission. The inventors have recognized and appreciated that current systems with more complex functions may cause paddle cards to have larger surface areas for providing the increased number of terminals for connection of cables to the paddle card. Further, the longest traces within the paddle card may also be longer as the number of terminals to connect to cables is increased because the array of terminals may be lengthened. Having longer traces as well as more variation between the longest and shortest traces may cause signal integrity deterioration. The inventors have recognized and appreciated techniques to provide paddle cards with reduced width, compared with conventional designs, to support the increased number of contact terminals with less impact on the length of the longest trace between a terminal and a contact pad.
[0068] In some embodiments, a paddle card may have two or more rows of contact pads for mating with complementary conductors, two or more rows of second pads for cable termination, and alternating dielectric layers and metal layers. The two or more rows of terminals may be disposed on respective metal layers. Such a configuration may enable conductive traces electrically connecting corresponding first and terminals to be substantially straight, and therefore reduce the lengths of the conductive traces. It may also reduce the size of the paddle card relative to paddle cards of conventional design in a lateral direction parallel to the rows. Alternatively or additionally, the size of a paddle card may be reduced in a direction perpendicular to the lateral direction and aligned with the direction in which the paddle card is inserted into a receptacle connector. These reductions in dimensions may be achieved without changing the thickness of the paddle card. With the paddle card assembly provided herein, the integrity of the signals transmitted therethrough can be maintained and/or improved at higher speed.
[0069]
[0070] The inventors have recognized and appreciated that signal distortion is usually a function of signal frequency, with more distortion occurring at higher signal frequencies. Shortening transmission distance may reduce a probability of occurrence of signal distortion during transmission. An increase in the distance of signal transmission may increase the probability of occurrence of signal distortion during transmission. Therefore, the increased length of the conductive traces 13 connected to the terminals 12 at the edge may be a factor influencing signal integrity.
[0071] The plug electrical connector 1 may be used for transmitting differential signals. The conductive traces 13 in the paddle card 10, such as differential pair of conductive traces S1 and S2, are connected to differential signal cables (for example, cables at the right side of
[0072] Yet another type of distortion is skew, comprising differential inter-pair skew and differential intra-pair skew. Skew is a change in the timing relationship between two differential signals, which are supposed to be correlated in time. Skew can happen when there is a difference in the length of the conductive traces 13 that carry those two differential signals. It takes longer for a differential signal to travel through longer traces, so two differential signals that start out correlated in time will be less correlated after passing through the plug electrical connector 1. Making the conductive trace lengths more uniform reduces inter-pair skew. Intra-pair skew is similar to inter-pair skew, but relates to a differential pair of conductive traces that carries one differential signal. Ideally, the signals on each pair will be 180 degrees out of phase. This means the signals are opposite of each other, and make the biggest possible difference between the signals on each differential pair of conductive traces. If one trace of the differential pair is longer, the signals that make up the differential signal change in phase, and the difference between them gets smaller. With reference to
[0073] The inventors have recognized and appreciated miniaturized paddle card assemblies that provide transmission with maintained and/or improved signal integrity at higher speed. A paddle card 100 of the embodiment of the present disclosure is described in detail below in connection with
[0074] The paddle card 100 may be for a plug electrical connector. A portion of the paddle card 100 may protrude out of a housing of the plug electrical connector. When mating with a receptacle electrical connector, the protruding portion of the paddle card 100 may be inserted into the receptacle electrical connector, and contact pads on the protruding portion may be electrically connected to the contact pads of the receptacle electrical connector. The receptacle electrical connector may be mounted on another printed circuit board, on which a processor or other electronic components may be disposed.
[0075] A base body 200 has a first end 210 and a second end 220 that are opposing along a first direction Y-Y. In some embodiments, the first end 210 of the base body 200 may be a plug-in end of the plug electrical connector. Under this circumstance, the first end 210 is a protruding portion of the paddle card 100. The plug electrical connector may connect the first end 210 to other circuits by means of plugging into a receptacle electrical connector, which is easy and convenient to operate. If possible, the paddle card 100 may also be used in a receptacle electrical connector or any other appropriate electrical connectors. In this case, the base body 200 may take any other appropriate configuration. In some embodiments, the second end 220 of the paddle card 100 may be connected to an edge of additional printed circuit board. It may also be connected to one end of a cable 500. The other end of the cable 500 may be used to connect to other components at another location within an electronic system. In some embodiments, the first direction Y-Y may be a longitudinal direction of the base body 200. When the paddle card 100 is used in the plug electrical connector, the first direction Y-Y may be a plug direction of the paddle card 100.
[0076] A surface of the first end 210 may be provided with a plurality of contact pads 310. The plurality of contact pads 310 may be in various types, e.g., gold fingers, conductive elastic sheets, etc. that are well-known to those skilled in the art or may appear in the future. The plurality of contact pads 310 may be arranged into n rows. n≥2 and is an integer. Each row of contact pads 310 may be arranged along a second direction X-X. The second direction X-X is different from the first direction Y-Y. An angle between the second direction X-X and the first direction Y-Y may be arbitrary. In some embodiments, the second direction X-X may be a transverse direction of the base body 200. Spacings between contact pads 310 in each row, and the numbers and types of each row of contact pads 310 may be the same or different. Contact pads 310 that are not in the same row may be the same or different. The first end 210 may be substantially the same as a front end of the paddle card 10 of the plug electrical connector 1. For a double density 0.80 mm connector, a size D2 of the first end 210 along the first direction Y-Y may be between 12.5-13.5 millimeters.
[0077] A surface of the second end 220 may be provided with a plurality of terminals 320. The plurality of terminals 320 may be in various types, e.g., gold fingers, conductive elastic sheets, welding pads, etc. that are well-known to those skilled in the art or may appear in the future. The contact pads 310 and the terminals 320 may be the same or different. The plurality of terminals 320 may be arranged into m rows. m≥2 and is an integer. Each row of terminals 320 may be arranged along the second direction X-X. Spacings between the terminals 320 in each row, and the numbers and types of each row of terminals 320 may be the same or different. Terminals 320 that are not in the same row may be the same or different.
[0078] The conductive traces 400 may be in various types that are well-known to those skilled in the art or may appear in the future. The conductive traces 400 may be disposed inside the base body 200. The contact pads 310 may be electrically connected to the terminals 320 through conductive traces 400. The conductive traces 400 may be straight or approximately straight. Being approximately straight refers to that first connecting ends 410 and/or second connecting ends 420 of the conductive traces 400 may have certain bending. However, a relatively long intermediate section 430 is straight, as illustrated in
[0079] As known by those skilled in the art, the conductive traces 400 are electrically connected between the contact pads 310 and the terminals 320, such that signal can be transmitted between the contact pads 310 and the terminals 320. The signals may comprise GND signals, power signals, control instruction signals, clock signals, and/or data signals, etc.
[0080] With reference to
[0081] In the paddle card 100 according to the embodiments of the present disclosure, a size of the second end 220 of the base body 200 along the second direction X-X is reduced, since the terminals 320 are arranged into m rows. By appropriate arrangement, the conductive traces 400 (for example, S3 and S4) can extend along a straight line or an approximately straight line and be electrically connected between the contact pads 310 and the terminals 320. In this way, there is no gap between the conductive traces 400 in the first direction Y-Y. Therefore, the base body 200 does not have to reserve room for it. Consequently, a size D4 of the second end 220 of the base body 200 along the first direction Y-Y may be reduced. In some embodiments, for a double density 0.80 mm connector, the size D4 of the second end 220 along the first direction Y-Y may be reduced to 5.5-7.5 millimeters. Further, D4 may be reduced to 6-7 millimeters. Even further, D4 may be reduced to about 6.5 millimeters. Moreover, the lengths of the conductive traces 400 are reduced, since the conductive traces 400 may extend in straight lines or approximately straight lines. In some embodiments, a length of S3 may be reduced to 13-14 millimeters, and a length of S4 may be reduced to 2.3-3.2 millimeters. Further, a length of S3 may be reduced to 13.3-13.8 millimeters, and a length of S4 may be reduced to 2-5-3.0 millimeters. Even further, a length of S3 may be reduced to about 13.5 millimeters, and a length of S4 may be reduced to about 2.8 millimeters.
[0082] Any signal distortion during the process of signal transmission by the electrical connector with the paddle card 100 may not be desired. If distortion occurs during signal transmission in the paddle card 100, communications between a circuit and another circuit which are connected by the paddle card 100 may be influenced. The electronic device may not detect signals correctly, or make more mistakes in detecting signals. Improving signal integrity of the paddle card 100 means less probability of occurrence of distortion during signal transmission through the electrical connector. In particular, distortion is more likely to occur when high-frequency signals are transmitted. Therefore, reducing the probability of distortion means that an electronic device with the electrical connector may operate at a higher frequency. In some embodiments, the electrical connector may satisfy requirement for PCIe Gen5 32 Gpbs.
[0083] As previously mentioned, multiple types of distortions may occur during signal transmission through the electrical connector using the paddle card 100. Reducing the lengths of the conductive traces 400 and increasing spacings between the conductive traces 400 may prevent signal distortions.
[0084] One type of distortion is crosstalk. When the electrical connector using the paddle card 100 transmits differential signals, the conductive traces 400 include differential pairs of conductive traces. In some embodiments, S1 and S2 in
[0085] Another type of distortion is signal attenuation. The longer the conductive traces 400 are, the more attenuation there is. Therefore, the electrical connector using the paddle card 100 has better anti-attenuation performance.
[0086] Yet another type of distortion is skew. As previously mentioned, for conventional electrical connectors, since lengths of S1, S2 and nearby conductive traces 13 are obviously different, differential inter-pair skew and differential intra-pair skew may be simultaneously present. However, in the electrical connector using the paddle card 100 illustrated in
[0087] As described, the paddle card 100 may have smaller sizes in both the first direction Y-Y and the second direction X-X, which enables the miniaturization of an electrical connector incorporating the paddle card 100. The paddle card 100 can be widely used in an electronic system, and have less limitation in use. Materials used to make the conductive traces 400 and the base body 200 may also be saved, thereby reducing the costs for manufacturing the paddle card 100. Meanwhile, distortions, such as crosstalk, signals attenuation and signal skew, that appear during signal transmission can be effectively relieved by the paddle card 100, thus ensuring integrity of signal transmission.
[0088] In some embodiments, at least 85% of each conductive trace may be straight. Further, at least 90% of each conductive trace may be straight. In some embodiments, at least 95% of each conductive trace may be straight. As described below, ends of conductive traces 400 may be configured to be bent. In this arrangement, when the conductive traces 400 are used to transmit differential signals, two conductive traces 400 in each differential pair of conductive traces may be as close as possible and have relatively long distance from two adjacent differential pairs of conductive traces by means of the small amount of portions of the conductive traces 400 that are not straight. In this way, differential signals can be better coupled and crosstalk may be effectively prevented, which ensure the integrity of transmission of differential signals. In such instance, lengths of the straight portions of conductive traces 400 are also related to overall lengths of the conductive traces 400. One of skill in the art may select the lengths of the straight portions of the conductive traces 400 as required. Optionally, when the conductive traces 400 are used to transmit other kinds of signals, each of the conductive traces 400 may be completely straight. In this case, the conductive traces 400 may be made as short as possible, thereby improving integrity of signal transmission.
[0089] In some embodiments, angles of straight portions of the plurality of conductive traces 400 to the first direction Y-Y may be within a range of −10 degree to 10 degrees. With respect to other embodiments, such a configuration may enable the base body 200 to be more compact, thereby reducing a size of the base body 200. Further, conductive traces 400 may be parallel to the first direction Y-Y.
[0090] In some embodiments, the first direction Y-Y and the second direction X-X may be perpendicular to each other, which causes the base body 200 more compact in comparison to other angles. It may be more convenient for mounting the electrical connector, since the electrical connector is usually applied in relatively narrow space. In embodiments where an electrical connector needs to be regularly plugged or exchanged (for example, the electrical connector is a plug electrical connector), the electrical connector using the preferred paddle card 100 is more applicable.
[0091] In some embodiments, two conductive traces 400 of each differential pair of conductive traces may have equal length. With reference to
[0092] In some embodiments, as shown in
[0093] Further, as illustrated in
[0094] In some embodiments, the plurality of conductive traces 400 may be distributed in a plurality of layers, thereby forming a plurality of conductive trace layers (not shown). A number of layers of conductive trace layers may be of 2, 3 or more. Optionally, the number of layers of conductive trace layers may be the same as a number of rows of contact pads 310 or a number of rows of terminals 320. The number of layers of the conductive trace layers may be different from the number of rows of contact pads 310 or the number of rows of terminals. In some embodiments, as illustrated in
[0095] In some embodiments, in the embodiment that the base body 200 is a printed circuit board, the printed circuit board may be fabricated by pressing a plurality of sheets together. Each sheet may have a polymer substrate (for example, epoxy). A metal layer is deposited on a side of the sheet and then patterned to form the conductive traces 400. A plurality of such sheets are stacked and then pressed at a high temperature to fuse these sheets together, thereby the base body 20 and conductive traces 400 disposed inside the base body 200 may be formed. It is easy to lower the level of difficulty in manufacturing the paddle card 100 and optimize the manufacturing process of the paddle card 100 by forming a plurality of conductive trace layers. A grounding layer (not shown) may be disposed between the conductive trace layers. In this way, crosstalk between the conductive traces 400 on adjacent conductive trace layers may be reduced. Therefore, the paddle card 100 has better anti-crosstalk performance. One of skill in the art can select the number of layers of the conductive trace layers as required.
[0096] In some embodiments, as illustrated by
[0097] In some embodiments, as illustrated in
[0098] In some embodiments, as shown in
[0099] In some embodiments, as shown in
[0100] In an embodiment where the paddle card 100 is manufactured by stacking and pressing, with reference to
[0101] The plurality of patterned metal layers 720 may comprise outer patterned metal layers positioned on surfaces of the outermost dielectric layers 710 and inner patterned metal layers positioned between adjacent dielectric layers 710. The inner patterned metal layers may be connected to the outer patterned metal layers through conductive vias 730. The outer patterned metal layers may form n rows of contact pads 310 and m rows of terminals 320. The n rows of contact pads 310 and m rows of terminals 320 may be positioned on two ends 210 and 220 of the base body that are opposing along a first direction Y-Y, respectively. The outer patterned metal layers forming different rows of terminals are positioned on different layers.
[0102] In some embodiments, the inner patterned metal layers may comprise a plurality of conductive traces 400. The two ends of the plurality of conductive traces 400 may be connected to the n rows of contact pads 310 and the m rows of terminals 320 through the conductive vias 730, respectively. In order to show the manufacturing of the paddle card 100 by stacking, as illustrated by
[0103] According to yet another aspect of the present disclosure, a method for manufacturing a paddle card is further provided. The method comprises: first, forming a metal layer on a dielectric layer 710; patterning the metal layer to form a patterned metal layer; then stacking a plurality of dielectric layers 710 each provided with a patterned metal layer thereon, and joining the plurality of dielectric layers 710 together to form a main body. Outer patterned metal layers positioned on surfaces of the main body form n rows of contact pads 310 and m rows of terminals 320. Then rows of contact pads 310 and them rows of terminals 320 are positioned on the two ends of the main body, respectively.
[0104] In some embodiments, the outer patterned metal layers forming different rows of terminals are positioned on different layers.
[0105] In some embodiments, inner patterned metal layers positioned in the main body comprise a plurality of conductive traces 400. The method further comprises: forming conductive vias 730 on the dielectric layers 710 to connect two ends of the plurality of conductive traces 400 to the n rows of contact pads 310 and the m rows of terminals 320, respectively.
[0106] According to yet another aspect of the present disclosure, an electrical connector is further provided, as illustrated in
[0107] In some embodiments, the electrical connector having the paddle card 100 may be attached to and detached from a mating electrical connector 800 by means of a housing assembly. With reference to
[0108] Therefore, the present disclosure has been described in way of the above several embodiments. It should be understood that a person skilled in the art can make more variations, modifications and improvements based on the teachings of the present disclosure, and these variations, modifications and improvements shall fall within the spirit and the protection scope of the present disclosure. The protection scope of the present disclosure is defined by the appended claims and their equivalent scopes. The foregoing embodiments are only for the purpose of illustration and description, and are not intended to limit the present disclosure to the scope of the described embodiments.
[0109] Various changes may be made to the illustrative structures shown and described herein. For example, the paddle card may be used to any suitable electrical connector, such as card edge connecter, backplane connector, daughter card connector, stacking connector, Mezzanine connector, I/O connector, chip socket, Gen Z connector, etc.
[0110] Furthermore, although many inventive aspects are shown and described with reference to a plug electrical connector, it should be appreciated that aspects of the present disclosure is not limited in this regard. As mentioned, any of the inventive concepts, whether alone or in combination with one or more other inventive concepts, may be used in other types of electrical connectors, such as right angle connectors, coplanar electrical connectors, etc.
[0111] In the description of the present disclosure, it needs to be understood that the orientation or positional relationship indicated by the orientation terms such as “front”, “rear”, “upper”, “lower”, “left”, “right”, “transverse”, “vertical”, “perpendicular”, “horizontal”, “top”, “bottom”, etc. is usually based on the orientation shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description. These orientation terms do not indicate or imply that the device or element has to have a specific orientation or be constructed and operated in a specific orientation, except as otherwise noted. Therefore, they cannot be understood as a limitation on the scope of the present disclosure. The orientation terms, “inside” and “outside”, refer to the inside and outside relative to the contour of each component itself.
[0112] For ease of description, spatial terms, such as “above”, “on”, etc., can be used herein to describe the spatial relationship between one or more components or features shown in the drawings and other components or features. It should be understood that the spatial terms not only include the orientation of the components shown in the drawings, but also include other orientations in use or operation. For example, if the components in the drawings are inverted as a whole, a component “above other components or features” becomes to the component “below other a components or structures”. Thus, the exemplary term “above” can include both orientations “above” and “below”. In addition, these components or features can also be positioned at other different angles (for example, rotated by 90 degrees or other angles), and this disclosure intends to cover all of these situations.
[0113] It should be noted that the terms used herein are only for describing specific implementations, and are not intended to limit to the exemplary implementations according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, the use of “including”, “comprising”, “having”, “containing”, or “involving”, and variations thereof herein, is meant to encompass the items listed thereafter (or equivalents thereof) and/or as additional items.
[0114] It should be noted that the terms “first” and “second” in the description, the claims and the drawings of the application are used to distinguish similar objects, and are not necessarily used to describe a specific sequence. It should be understood that numbers used in this way can be interchanged under appropriate circumstances such that the embodiments of the present disclosure described herein can be implemented in a sequence other than those illustrated or described herein.