Patent Application
20240364065
Aspects of the present disclosure relate generally to soldering connections on electronic circuits, and in particular to soldering on a substrate with a low melting point.
Logitech is striving to make its products more sustainable through new designs. A problem with electronics is the difficulty of recycling printed circuit boards (PCBs). It would be desirable to have a more easily recyclable substrate, such as a plastic like polyethylene terephthalate (PET). However, the temperature required for soldering to conductors on PET will melt the PET.
There are a variety of methods to make connections with conductive traces on a substrate. These include soldering with heat, ultrasonic welding, ACF (anisotropic conductive film) bonding, hand soldering, conductive glue and conductive tape. These involve various tradeoffs of cost, electrical resistance, yield, etc.
Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In some embodiments, a method for soldering to a conductor on a first substrate with a melting temperature below a soldering temperature is provided. A second substrate is attached to the first substrate around a soldering point. The second substrate is smaller than the first substrate and has a melting temperature above the soldering temperature. A soldering material is applied to the soldering point and heat is applied to the soldering point with a soldering head smaller than the second substrate. The first substrate deforms (e.g., melts) proximate the soldering point at the soldering temperature. However, support for the first conductor is provided with the second substrate in place of the first substrate proximate the soldering point where the first substrate is deformed.
In some embodiments, the first substrate is polyethylene terephthalate (PET), the second substrate is a polyimide (e.g., Kapton® tape) and the first conductor is a copper trace. The Kapton® tape is attached to the copper trace and the PET using an adhesive.
In some embodiments, there is a depression in the first conductor at the soldering point to provide a multi-dimensional surface where solder can attach more securely. In embodiments, the depression is a via extending through the first substrate to a second conductor on a second side of the first substrate opposite the first conductor. The first conductor is connected to the second conductor with the via at the soldering point.
In some embodiments, a third substrate (e.g., PCB) with a soldering pad is attached to the first substrate so that the soldering pad is aligned with the soldering point. The soldering material attaches to the soldering pad. The soldering connection can be strengthened with the inclusion of a via, which can also aid the application of the solder material.
This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this disclosure, any or all drawings, and each claim.
The foregoing, together with other features and examples, will be described in more detail below in the following specification, claims, and accompanying drawings.
Aspects and features of the various embodiments will be more apparent by describing examples with reference to the accompanying drawings, in which:
While certain embodiments are described, these embodiments are presented by way of example only, and are not intended to limit the scope of protection. The apparatuses and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the example methods and systems described herein may be made without departing from the scope of protection.
In some embodiments, a more sustainable substrate than a PCB, such as PET, can be used for conductors (e.g., copper) even though it melts at soldering temperatures.
In one embodiment, the first substrate is PET, the second substrate is a Kapton® film, and the conductive traces are copper. The temperature required for soldering is typically about 250 degrees C. PET melts at approximately 80 degrees C. (glass point) and Kapton® tape (polyimide) melts at approximately 400 degrees C. Thus, PET will melt at the soldering temperature, but the Kapton® tape will not.
In an alternate embodiment, the opening 112 is sufficiently large, and the soldering head correspondingly small, so that the portions of first substrate 102 in overlap region 124 do not melt. Thus the second substrate 114 will be in direct contact with a PCB (not shown) in the opening zone 112 in the areas around the copper traces.
The method and structure of
In an alternate embodiment, a single-sided substrate is used, with traces on only one side. The circular contact areas 206 are still used, with an optional depression or hole, not necessarily a via extending all the way through the substrate. Such a hole enables the solder to better connect to the conductive trace.
The second substrate 114 of
In embodiments, the methods describe herein are applicable to either single or double layer membranes. The above-described figures show solder points aligned in zig-zag, to reduce overall pitch. They can also be aligned linearly, or can be any other pattern, such as much further separated solder points. By using Kapton® tape placed locally, costs are reduced since Kapton® tape is widely available and cheaper than PCBs. The methods described herein allow for standard soldering methods, thus eliminating the need to design special soldering equipment and methods. The first substrate can alternately be any material that would melt/deform/degrade with heat (not limited to PET).
In embodiments, the openings in the second substrate (e.g., Kapton® tape) are kept small for better mechanical stability. In addition, the Kapton® tape may overlap the PET substrate and attach directly to an electronic board for better mechanical stability.
In one embodiment, for the various embodiments described above, Kapton® tape 302 is 0.05-0.1 mm thick, PET membrane 328 is 0.02-0.1 mm thick, and PCB 3134 is 0.5-1.5 mm thick.
In an alternative embodiment, a second Kapton® tape and adhesive is attached to the bottom of the PET membrane, between the PET membrane and the PCB. The second Kapton® tape has an opening to expose solder pad 316 and the via. The second Kapton® tape adds additional mechanical support for the copper traces, which may be desirable in some applications. In one embodiment, the second Kapton® tape between the PET membrane and PCB is thinner than the first Kapton® tape.
The charging pad of
In alternate embodiments, thin copper wire can be used instead of copper traces. Flexible membranes other than PET could be used, such as more sustainable materials made from biomass. Other examples include bio-PET, recycle rPET, poly(ethylene 2,5-furandicarboxylate) (PEF), poly(trimethylene 2,5-furandicarboxylate) (PTF), lignin-based thermoplastic polymers, (Bio) degradable aliphatic polyesters and poly(lactic acid) (PLA). The second, supporting substrate could be something other than polyimide, such as a different heterocyclic polymer. Also, other types of polyimides than Kapton® tape could be used, such as 3 rd generation polyimides with additives, filled polyimides or low-flow polyimides.
In addition to soldering traces, the techniques described herein could be used to solder semiconductor package pins to a substrate, with the second substrate being attached to the area for the chip package and extending a few millimeters beyond the connector holes for the package pins.
Numerous specific details are set forth herein to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter may be practiced without these specific details. In other instances, methods, apparatuses, or systems that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter. The various embodiments illustrated and described are provided merely as examples to illustrate various features of the claims. However, features shown and described with respect to any given embodiment are not necessarily limited to the associated embodiment and may be used or combined with other embodiments that are shown and described. Further, the claims are not intended to be limited by any one example embodiment.
While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, it should be understood that the present disclosure has been presented for purposes of example rather than limitation, and does not preclude inclusion of such modifications, variations, and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art. Indeed, the methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the present disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the present disclosure.
Although the present disclosure provides certain example embodiments and applications, other embodiments that are apparent to those of ordinary skill in the art, including embodiments which do not provide all the features and advantages set forth herein, are also within the scope of this disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by reference to the appended claims.
The system or systems discussed herein are not limited to any particular product, hardware architecture or configuration. Embodiments of the methods disclosed herein may be performed in the operation of such computing devices. The order of the steps presented in the examples above can be varied—for example, steps can be re-ordered, combined, and/or broken into sub-steps. Certain steps or processes can be performed in parallel.
Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain examples include, while other examples do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more examples or that one or more examples necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular example.
The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. The use of “adapted to” or “configured to” herein is meant as open and inclusive language that does not foreclose devices adapted to or configured to perform additional tasks or steps. Additionally, the use of “based on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Similarly, the use of “based at least in part on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based at least in part on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Headings, lists, and numbering included herein are for ease of explanation only and are not meant to be limiting.
The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of the present disclosure. In addition, certain method or process steps may be omitted in some embodiments. The methods and processes described herein are also not limited to any particular sequence, and the steps or states relating thereto can be performed in other sequences that are appropriate. For example, described steps or states may be performed in an order other than that specifically disclosed, or multiple steps or states may be combined in a single step or state. The example steps or states may be performed in serial, in parallel, or in some other manner. Steps or states may be added to or removed from the disclosed examples. Similarly, the example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed examples.
The various embodiments illustrated and described are provided merely as examples to illustrate various features of the claims. However, features shown and described with respect to any given embodiment are not necessarily limited to the associated embodiment and may be used or combined with other embodiments that are shown and described. Further, the claims are not intended to be limited by any one example embodiment.
Although the present disclosure provides certain example embodiments and applications, other embodiments that are apparent to those of ordinary skill in the art, including embodiments which do not provide all of the features and advantages set forth herein, are also within the scope of this disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by reference to the appended claims.
