Patent Application
20120012382
The present disclosure generally relates to Electromagnetic Interference (EMI), and more particularly (but not exclusively) to conductive films for EMI shielding applications.
This section provides background information related to the present disclosure which is not necessarily prior art.
Electronic equipment, devices, components, parts, etc. generate undesirable electromagnetic energy that can interfere with the operation of proximately located electronic equipment. Such EMI interference may adversely affect the operating characteristics of the electrical component and the operation of the associated device.
Accordingly, it is not uncommon to provide shielding and/or grounding for electronic components that use circuitry that emits or is susceptible to electromagnetic interference. These components may be shielded to reduce undesirable electromagnetic interference and/or susceptibility effects with the use of a conductive shield that reflects or dissipates electromagnetic charges and fields. Such shielding may be grounded to allow the offending electrical charges and fields to be dissipated without disrupting the operation of the electronic components enclosed within the shield. By way of example, sources of undesirable electromagnetic energy are often shielded by a stamped metal enclosure.
In addition, electrical components, such as semiconductors, transistors, etc., typically have pre-designed temperatures at which the electrical components optimally operate. Ideally, the pre-designed temperatures approximate the temperature of the surrounding air. But the operation of electrical components generates heat which, if not removed, will cause the electrical component to operate at temperatures significantly higher than its normal or desirable operating temperature. Such excessive temperatures may adversely affect the operating characteristics of the electrical component and the operation of the associated device.
To avoid or at least reduce the adverse operating characteristics from the heat generation, the heat should be removed, for example, by conducting the heat from the operating electrical component to a heat sink. The heat sink may then be cooled by conventional convection and/or radiation techniques. During conduction, the heat may pass from the operating electrical component to the heat sink either by direct surface contact between the electrical component and heat sink and/or by contact of the electrical component and heat sink surfaces through an intermediate medium or thermal interface material (TIM). The thermal interface material may be used to fill the gap between thermal transfer surfaces, in order to increase thermal transfer efficiency as compared to having the gap filled with air, which is a relatively poor thermal conductor. In some devices, an electrical insulator may also be placed between the electrical component and the heat sink, in many cases this is the TIM itself.
As used herein, the term electromagnetic interference (EMI) should be considered to generally include and refer to both electromagnetic interference (EMI) and radio frequency interference (RFI) emissions. The term “electromagnetic” should be considered to generally include and refer to both electromagnetic and radio frequency from external sources and internal sources. Accordingly, the term shielding (as used herein) generally includes and refers to both EMI shielding and RFI shielding, for example, to prevent (or at least reduce) ingress and egress of EMI and RFI relative to a shielding device in which electronic equipment is disposed.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
According to various aspects, exemplary embodiments are provided of EMI shielding materials. In one exemplary embodiment, an EMI shielding material generally includes a conductive metal layer disposed on a thin carrier film. The EMI shielding material may be sufficiently compliant such that the conductive metal layer and thin carrier film are capable of conforming to an irregular surface when the EMI shielding material is applied to the irregular surface.
In another exemplary embodiment, an EMI shielding material generally includes a conductive metal layer disposed on the thin carrier film. The conductive metal layer is sufficiently thin such that the EMI shielding material is capable of conforming to an irregular surface when the EMI shielding material is applied to the irregular surface.
In a further exemplary embodiment, an EMI shielding material generally includes a thin carrier film having a first side and conductive metal layer applied to the first side of the thin carrier film. The conductive metal layer and the thin carrier film together may have a combined thickness that is sufficiently thin to enable the EMI shielding material to conform to an irregular surface when the EMI shielding material is applied to the irregular surface.
Additional aspects provide methods relating to EMI shielding materials, such as methods of using and/or making the EMI shielding materials. In one exemplary embodiment, a method for making an EMI shielding material generally includes depositing conductive metal onto a carrier film, to thereby form a conductive metal layer. A method may also include applying the EMI shielding material to a plastic article, whereby the EMI shielding material is operable for imparting EMI shielding capability to the plastic article. Additionally, or alternatively, a method may include applying a release liner to the conductive metal layer.
Further aspects and features of the present disclosure will become apparent from the detailed description provided hereinafter. In addition, any one or more aspects of the present disclosure may be implemented individually or in any combination with any one or more of the other aspects of the present disclosure. It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the present disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Disclosed herein are various exemplary embodiments of Electromagnetic Interference (EMI) shielding materials that include a conductive metal layer and a thin carrier film material (e.g., a thin layer of polymer or release material, etc.). Some exemplary embodiments may optionally include a release coating and/or film disposed across an entire surface of the conductive metal layer. Yet other exemplary embodiments may optionally include a release coating and/or film disposed across only portions of that entire surface, such as in a predetermined pattern (e.g., striped pattern (
In various embodiments, an EMI shielding material includes a thin carrier film and a conductive metal layer disposed on the thin carrier film, which is sufficiently compliant such that the conductive metal layer and thin carrier film are able to conform to an irregular surface (e.g., a non-uniform surface that is not flat or continuous, a non-flat surface, curved surface, uneven surface, surface without symmetry, even shape, or formal arrangement, etc.), such as one or more surfaces within a mold cavity or one or more surfaces of a molded article on which the EMI shielding material is intended to be or is applied. Advantageously, this allows the EMI shielding material to become part of a molded article, with the conductive metal layer disposed on the exterior of the molded article and the thin carrier film adhered to the molded article.
In one or more exemplary embodiments, the conductive metal layer has a thickness of less than or equal to 0.0005 inches, and the thin carrier film has a thickness of less than or equal to about 0.001 inches. In other exemplary embodiments, the conductive metal layer may have a thickness falling within a range of about 5 Nanometers (50 Angstroms) to about 100 Nanometers (1000 Angstroms), and the thin carrier film may have a thickness falling within a range of about 0.2 micrometers to about 5 micrometers. In such embodiments, the conductive metal layer may have a thickness of 5 Nanometers, 100 Nanometers, or any value falling between 5 Nanometers and 100 Nanometers, and the thin carrier film may have a thickness of 0.2 micrometers, 5 micrometers, or any value falling between 0.2 micrometers and 5 micrometers. These numerical dimensions disclosed herein are provided for illustrative purposes only. The particular dimensions are not intended to limit the scope of the present disclosure, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
The conductive metal layer and the thin carrier film together may have a combined thickness that is effective to enable the EMI shielding material to conform to an irregular surface when the EMI shielding material is applied to the irregular surface. The application of the metallized transfer film or conductive metal layer to a irregular surface of a molded article may provide or imparts EMI shielding capability to the molded part, without requiring the article to be molded or made of a conductive plastic or painted with a conductive paint.
In addition, the metallized transfer film or conductive metal layer on a carrier film, and release coating and/or film may also provide for or establish a heat-conducting path. The thinness of the metallized transfer film and release coating and/or film also allows for good conformance with the mating surface, and helps improve thermal conduction. Thermal conduction depends, at least in part, upon the degree of effective surface area contact with the conductive metal layer. The ability to conform to a mating surface is important, as a molded article for EMI shielding may not be perfectly flat or smooth, and any air gaps or spaces between the conductive metal layer and article surfaces would decrease thermal conductivity (air being a relatively poor thermal conductor). Therefore, removal of air spaces may help increase thermal conductivity to the conductive metal layer.
Some alternative exemplary embodiments disclosed herein may also include a protective liner disposed on a side of the EMI shielding material opposite the thin carrier film. The protective liner may preferably disposed over the metallized transfer layer or conductive metal layer, and may be removed before application or deposition of the EMI shielding material onto a surface. Use of the protective liner may help reduce the chance of surface imperfections as a result of handling the EMI shielding material. The protective liner may be configured to help protect the conductive metal layer and/or release coating during transport, shipping, handling, etc. In addition, some alternative exemplary embodiments may also include a release coating, which is a low surface energy coating that allows for easy removal of the EMI shielding material from a surface in contact with the release coating. Some embodiments may include a release coating having a thickness of 0.0005 inches or less, e.g., 0.0005 inches, 5 angstroms, etc. In embodiments having a release coating or liner, the protective liner may be disposed over the release coating or liner on the side of the EMI shielding material that is opposite the thin carrier film. Some embodiments may include a release liner having thickness falling within a range of about 1 mil (0.025 millimeters) to about 10 mils (0.25 millimeters). In such embodiments, the release liner may have a thickness of 1 mil, 10 mils, or any value falling between 1 mil and 10 mils. These numerical dimensions disclosed herein are provided for illustrative purposes only. The particular dimensions are not intended to limit the scope of the present disclosure, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
In addition, the thin carrier film material may provide improved consistency in product thickness and strength with less adverse impact on the electrical conductivity of the metal layer, as compared to plated metal layers whose electrical conductivity is dependent on consistent deposition onto the article. In various embodiments, the thin carrier film material preferably comprises at least one or more of polymer, teflon, polyester, acrylic, or plastic. In some embodiments, the thin carrier film material preferably has a thickness of less than or equal to about 100 gauge or 25 microns/micrometers (0.001 inches), which is sufficiently thin to effectively enable the EMI shielding material to conform to an irregular surface on which the EMI shielding material is intended to be applied. By way of further example, the thin carrier film may have a thickness falling within a range of about 0.2 micrometers to about 5 micrometers, such that the thin carrier film may have a thickness of 0.2 micrometers, 5 micrometers, or any value falling between 0.2 micrometers and 5 micrometers. These numerical dimensions disclosed herein are provided for illustrative purposes only. The particular dimensions are not intended to limit the scope of the present disclosure, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
Referring now to
Thin carrier film 116 may preferably comprise at least one or more of polymer, teflon, polyester, acrylic, or plastic. In addition, the thin carrier film 116 may be configured to have a thickness of less than or equal to about 100 gauge or 25 microns/micrometers (0.001 inches), which is sufficiently thin to effectively enable the EMI shielding material 100 to conform to an irregular surface (e.g., surface inside a mold cavity, etc.) on which the EMI shielding material 100 is intended to be applied. Alternatively, the thin carrier film may be made from other materials and/or be thicker or thinner than 25 micrometers or 0.001 inches. For example, the thin carrier film may have a thickness falling within a range of about 0.2 micrometers to about 5 micrometers, such that the thin carrier film may have a thickness of 0.2 micrometers, 5 micrometers, or any value falling between 0.2 micrometers and 5 micrometers. These numerical dimensions disclosed herein are provided for illustrative purposes only, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
The metallized transfer layer or conductive metal layer 104 may be directly provided or applied to a side of the thin carrier film 116. For example, the metallized transfer layer or conductive metal layer 104 may be applied or provided via vapor deposition, vacuum metallization, sputtering, flash coating, electrolytic plating, evaporating, coating using gravure, flexographic coating, printing material in a pattern, other coating technologies, among other suitable processes.
The metalized transfer layer or conductive metal layer 104 may disposed on the thin carrier film 116, such that the conductive metal layer 104 has a sufficient thinness of less than or equal to 0.0005 inches, to allow the EMI shielding material 100 to conform to an irregular surface on which the EMI shielding material 100 is intended to be applied. In one or more exemplary embodiments, the conductive metal layer 104 may have a thickness falling within a range of about 5 Nanometers (50 Angstroms) to about 100 Nanometers (1000 Angstroms), such that the conductive metal layer 104 has a thickness of 5 Nanometers, 100 Nanometers, or any value falling between 5 Nanometers and 100 Nanometers. These numerical dimensions disclosed herein are provided for illustrative purposes only, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
The metallized transfer layer or conductive metal layer 104 may be formed from various materials, which preferably are good electrical and thermal conductors and are relatively compliant, conformable, or flexible for conforming to a surface (e.g., a surface within a mold cavity, a surface of a molded article, a surface of an electrical component or heat sink, etc.). Using a material that is a good thermal conductor and capable of good conformance with a mating surface helps provide improved thermal conductivity. In addition, the metallized transfer layer or conductive metal layer 104 may also be configured to help the EMI shielding material 100 release cleanly and easily from an electrical component or heat sink, for example, for reworking or servicing the electrical component. In some exemplary embodiments, the metallized transfer layer or conductive metal layer 104 comprises copper or copper alloy. Alternative embodiments may include one or more other materials and/or different thicknesses used for the metallized transfer layer or conductive metal layer 104, including other metals besides copper (e.g., aluminum, silver, tin, etc.). By way of further example, exemplary embodiments may include a metallized transfer layer or conductive metal layer 104 comprising aluminum having a thickness of less than or equal to about 0.0005 inches. Other embodiments may have a metallized transfer layer or conductive metal layer 104 with a thickness of about 0.0002 inches, 0.0001 inches, 5 angstroms, less than 0.0001 inches, less than 5 angstroms, 5 Nanometers (50 Angstroms), 100 Nanometers (1000 Angstroms), a value falling between 5 Nanometers and 100 Nanometers, etc. These numerical dimensions disclosed herein are provided for illustrative purposes only, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
Also disclosed herein, the metallized transfer film or conductive metal layer 104 may be provided in some embodiments as a subcomponent or part of a product from the Dunmore Corporation of Bristol, Pa., such as products under the trade name Dun-Tran (e.g., Dunmore DT273 metallized film having a heat-activated adhesive layer, Dunmore DT101 metallization transfer layer, etc.) or other products having a metallization or metal layer or film with a polymer coating.
The table immediately below lists various exemplary materials that may be used as a metallized transfer layer or conductive metal layer 104 in any one or more exemplary embodiments described and/or shown herein. This table and the materials and properties listed therein are provided for purposes of illustration only and not for purposes of limitation.
Various processes and technologies may be employed to provide a metallized transfer layer or conductive metal layer 104 on a carrier film, depending on the particular embodiment. Some example processes include vapor deposition, vacuum metallization, lamination, calendaring, sputtering, electrolytic plating, evaporating, flash coating, coating using gravure, flexographic coating, printing in a pattern, other coating technologies, transferring or providing via a transfer carrier (e.g., polyester liner, etc.), among other suitable processes. By way of example, a metallized transfer layer or conductive metal layer 104 may be configured to release from a carrier film for transfer to a molded article or electrical component, for example.
In addition,
Another example may include a conductive metal layer formed directly on top of the carrier film 116 with a protective polymer liner 140 directly on top of the conductive metal layer 104, as shown in
Referring now to
As shown in
The thin carrier film 216 may preferably have a thickness of less than or equal to about 100 gauge or 25 microns/micrometers (0.001 inches), which is sufficiently thin to effectively enable the EMI shielding material 200 to conform to an irregular surface on which the EMI shielding material 200 is intended to be applied. Alternatively, the thin carrier film may be made from other materials and/or be thicker or thinner than 25 micrometers or 0.001 inches. For example, the thin carrier film may have a thickness falling within a range of about 0.2 micrometers to about 5 micrometers, such that the thin carrier film may have a thickness of 0.2 micrometers, 5 micrometers, or any value falling between 0.2 micrometers and 5 micrometers. These numerical dimensions disclosed herein are provided for illustrative purposes only, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
With continued reference to
The metallized transfer layer or conductive metal layer 204 preferably comprises a copper or copper alloy, but may alternatively include one or more other materials including other metals besides copper (e.g., aluminum, silver, tin, etc.). By way of further example, exemplary embodiments may include a conductive metal layer 204 comprising aluminum having a thickness of less than or equal to about 0.0005 inches. Other embodiments may have a metallized transfer layer or conductive metal layer 204 with a thickness of about 0.0002 inches, 0.0001 inches, 5 angstroms, less than 0.0001 inches, less than 5 angstroms, 5 Nanometers (50 Angstroms), 100 Nanometers (1000 Angstroms), a value falling between 5 Nanometers and 100 Nanometers, etc. These numerical dimensions disclosed herein are provided for illustrative purposes only, as the dimensions may be varied for other embodiments depending, for example, on the particular application in which the embodiment will be used.
Also disclosed herein, the metallized transfer film or conductive metal layer 204 may be provided in some embodiments as a subcomponent or part of a product from the Dunmore Corporation of Bristol, Pa., such as products under the trade name Dun-Tran (e.g., Dunmore DT273 metallized film having a heat-activated adhesive layer, Dunmore DT101 metallization transfer layer, etc.) or other products having a metallization or metal layer or film with a polymer coating.
In this illustrated embodiment of
The release liner 230 (and/or coating 220) may be disposed over the entire surface of the metallized transfer layer or conductive metal layer 204. Or, for example, the release liner 230 (and/or coating 220) may be disposed along two or more portions of the metallized transfer layer or conductive metal layer 204 on a side opposite the thin carrier film 216. By way of example, the release liner 230 (and/or coating 220) may be disposed on the metallized transfer layer or conductive metal layer 204 in a predetermined pattern (e.g., a striped pattern (
The EMI shielding material 200 may be positioned, sandwiched, or installed between a heat sink and an electrical component (e.g., printed circuit board assembly, central processing unit, graphics processing unit, memory module, other heat-generating component, etc.). When in contact with a surface of the electrical component, a thermally conducting heat path may be established or defined from the electrical component, through the metallized transfer layer or conductive metal layer 204, the release liner 230 and/or coating 220 to the heat sink. In this example, the metallized transfer layer or conductive metal layer 204 may be applied to either the electrical component or heat sink, and the release liner 230 (and/or coating 220) may allow for a clean release of the EMI shielding material 200 from the electrical component or heat sink respectively, such as when the heat sink is removed for obtaining access to the electrical component for servicing, repair, replacement, etc.
The release liner 230 and release coating 220 may be configured to cause a preferential release from a preferred surface, in order to stay with or stick to a component to be shielded, or alternatively to stick to a heat sink. The release liner 230 and release coating 220 may allow for easier handling and installation by inhibiting adherence, stickiness or tacky surface tack, such as to the hands of the installer or to a surface of a component. In the illustrated embodiment of
Various materials may be used for the release coating 220 and release liner 230 shown in
As just mentioned, the release liner 230 (
During an exemplary installation process, side 212 of the metallized transfer layer or conductive metal layer 204, or the exposed side of release coating 220 (where included), may be positioned generally against the surface of a molded article. The thin carrier film 216 may be colored or have a different color than the metallized transfer layer or conductive metal layer 204, such that the thin carrier film 216 is more readily recognizable and/or differentiated from the metallized or conductive metal layer 204. In turn, this coloring scheme (which may also be used in other disclosed embodiments herein, such as the illustrated embodiment of
After the EMI shielding material 200 is applied, for example, to a surface of a electronic component, heat sink, or in a mold cavity, the carrier film 216 may be removed (e.g., peeled off, etc.) from the applied EMI shielding material 200. In some embodiments, the upper surface or side 224 of the metallized transfer layer or conductive metal layer 204 may further be positioned against and in thermal contact with a surface of a heat sink or electrical component (e.g., component of a high frequency microprocessor, printed circuit board, central processing unit, graphics processing unit, laptop computer, notebook computer, desktop personal computer, computer server, thermal test stand, etc.). The surface or side 224 of the metallized transfer layer or conductive metal layer 204 may be pressed against the component to establish good thermal contact with a surface of the component. In some embodiments, the upper surface or side 224 of the metallized transfer layer or conductive metal layer 204 may comprise a release liner 230 that is positioned against and in thermal contact with a surface of an electrical component, to permit the EMI shielding material 200 to be removed from the component for rework or replacement. The description provided above regarding an exemplary installation process for the EMI shielding material 200 is provided for purposes of illustration only, as other embodiments of an EMI shielding material may be configured and/or installed differently. For example, some embodiments include an EMI shielding material having a protective liner (see, for example, protective liner 140 in
With continued reference to
It should be noted that other embodiments of EMI shielding materials may not include either one or both of release coating 220 and release liner 230. For example, another embodiment of an EMI shielding material generally includes a metallized transfer layer or conductive metal layer 204 on a thin carrier film 216, without any release coating 220 or release liner 230. Further embodiments of an EMI shielding material generally include a metallized transfer layer or conductive metal layer 204 on a thin carrier film 216, and a release coating (e.g., 220, etc.), without any release liner (e.g., 230, etc.) between the release coating 220 and the conductive metal layer 204. Additional embodiments of an EMI shielding material generally include a metallized transfer layer, or conductive metal layer 204 on a thin carrier film 216, and only a release liner (e.g., 230, etc.), such that the EMI shielding material does not include any release coating (e.g., 220, etc.).
Descriptions will now be provided of various exemplary methods for making or producing EMI shielding materials (e.g., 100 (
Process 400 may further include laminating the conductive metal layer (e.g., 204, a copper layer, an aluminum layer, a tin layer, one or more layers formed from other metals on a transfer film, etc.) to the release liner (e.g., 216,
Embodiments (e.g., 100, 200, 500, 600, 700, etc.) disclosed herein may be used with a wide range of electronic components, EMI sources, heat-generating components, heat sinks, among others. By way of example only, exemplary applications include printed circuit boards, high frequency microprocessors, central processing units, graphics processing units, laptop computers, notebook computers, desktop personal computers, computer servers, thermal test stands, portable communications terminals (e.g., cellular phones, etc.), etc. Accordingly, aspects of the present disclosure should not be limited to use with any one specific type of end use, molded article, electrical component, part, device, equipment, etc.
Numerical dimensions and the specific materials disclosed herein are provided for illustrative purposes only. The particular dimensions and specific materials disclosed herein are not intended to limit the scope of the present disclosure, as other embodiments may be sized differently, shaped differently, and/or be formed from different materials and/or processes depending, for example, on the particular application and intended end use.
It is envisioned that two or more specific exemplified values for a given parameter may define endpoints for a range of values that may be claimed for the parameter. For example, if a dimension or parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that dimension or parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a dimension or parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if dimension or parameter X is exemplified herein to have values in the range of 1 to 10, or 2 to 9, or 3 to 8, it is also envisioned that dimension or parameter X may have other ranges of values including 1 to 9, 1 to 8, 1 to 3, 1 to 2, 2 to 10, 2 to 8, 2 to 3, 3 to 10, 3 to 9, etc.
Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
This patent application is a continuation of and claims the benefit of International Application No. PCT/US2009/043716 filed May 13, 2009. The disclosure of the application identified in this paragraph is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2009/043716 | May 2009 | US |
| Child | 13243685 | US |
