Abstract:
A method and apparatus form electrical connections between electronic circuits and conductive threads ( 102, 104, 106, 108 ) that are interwoven into textile material ( 130 ). Electronic circuits ( 128 ), such as semiconductor dies, are connected to a carrier ( 132 ) and electrical connections ( 136 ) are made to conductive connection areas ( 110, 112, 114, 116 ) on the carrier ( 132 ). Conductive stitching ( 202, 204, 206, 208 ) provides electrical contacts for both the conductive connection areas ( 110, 112, 114, 116 ) on the carrier ( 132 ) and the conductive threads ( 102, 104, 106, 108 ) that are interwoven into the textile material ( 130 ). Optionally, a thin, flexible substrate material ( 132 ) is perforated during the stitching process.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to the field of electrical connections and more specifically to electrical connections formed in or associated with textile materials. 
     BACKGROUND OF THE INVENTION 
     Applications for electronic circuits include connecting electronic circuits to conductors within textile materials. Textile materials, such as commonly available fabrics, are able to include electronic circuits for a variety of purposes. One such application includes “wearable electronics” whereby electronic circuits are attached to or embedded into clothing. These electronic circuits can be connected to conductive threads woven into the cloth of the clothing to provide electrical interfaces between those electronic circuits and other components, such as switches or other input/output devices. 
     An obstacle to the cost effective construction of such wearable electronic circuits is that it is difficult to connect the electronic components, such as integrated circuits, to conductive threads sewn into the textile garment. Conductive threads create efficient “wearable wires,” but connecting these wires to devices has been difficult to do in an efficient and cost effective manner that is sufficiently robust to withstand being worn and washed. Solutions that use solder and/or printed circuit boards further complicate and restrict the design and construction of low-cost and practical clothing. 
     Therefore a need exists to overcome the problems with the prior art as discussed above. 
     SUMMARY OF THE INVENTION 
     In accordance with an exemplary embodiment of the present invention, an electronic circuit module arrangement has an electronic circuit module with at least one connection point and a carrier that is sewn through by forming perforations in the carrier during a passing of a thread through the carrier. The electronic circuit module arrangement further has at least one connection areas where each of the at least one connection areas is in mechanical contact with the carrier and in electrical coupling with the at least one connection point. 
     In accordance with another aspect of the present invention, an electrical circuit connection has a carrier that is sewn through. The electrical circuit connection further has at least one connection areas where each of the at least one connection areas is in mechanical contact with the carrier. The electrical circuit connection also has a textile material with at least one interwoven conductive thread that is a part of the textile material. The electrical connection further has at least one conductive stitching where each of the at least one conductive stitching consists of conductive material and is, for example, woven, knitted, and/or stitched through the carrier and the textile material so as to form an electrical connection between one of the at least one connection areas and one of the at least one interwoven conductive thread. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
         FIG. 1  illustrates an unattached carrier  100  prior to attachment to a textile material, according to an exemplary embodiment of the present invention. 
         FIG. 2  illustrates an attached sewn-through carrier  200  according to an exemplary embodiment of the present invention. 
         FIG. 3  illustrates an unattached hole-connection carrier  300  according to an exemplary alternative embodiment of the present invention. 
         FIG. 4  illustrates an attached hole-connection carrier  400  according to the alternative exemplary embodiment of the present invention. 
         FIG. 5  illustrates a processing flow diagram for implementing a method for connecting two electrical circuits in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms as described in the non-limiting exemplary embodiments of  FIGS. 1 through 4 . Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. 
     The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language). The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term woven, as used herein, is defined to include but is not limited to woven, knitted, stitched, or embroidered. 
       FIG. 1  illustrates an unattached carrier  100  prior to attachment to a textile material, according to an exemplary embodiment of the present invention. The exemplary unattached carrier  100  illustrates a textile material  130  with four conductive threads interwoven therein. A first conductive thread  102 , a second conductive thread  104 , a third conductive thread  106  and a fourth conductive thread  108  are interwoven conductive threads that are a part of the textile material shown in this example. Further embodiments of the present invention incorporate textile material with only one interwoven conductive thread or any number of interwoven conductive threads that are used to convey electrical power and/or signals to a circuit, as is described below. 
     The textile material  130  of the exemplary embodiment is a conventional material made of any of the numerous materials adapted for fabrics. It is clear that any suitable material is able to be used in embodiments of the present invention. Textile materials can be woven from, for example and without limitation, cotton, polyester, wool, and other such materials. Interwoven conductive threads, such as the first conductive thread  102 , are formed in an exemplary embodiment of carbon fiber. Further embodiments include interwoven conductive threads that include copper, silver and/or gold conductors. Such threads are able to be solid or stranded metallic threads or cloth insulating threads that include intermixed conductive materials to form a conductive circuit path. These interwoven conductive threads are able to be accurately woven into textile material by, for example, conventional or modified embroidery machines. Interwoven conductive threads woven into the textile material  130  are able to have an insulating coating or be uninsulated. Some embodiments that use uninsulated conductive threads (i.e., lacking an insulating cover), such as the first conductive thread  102 , use the textile material  130  as a liner that is either sandwiched between two or more other layers of textile material or that is a backing for a single layer of material that forms an outer layer of an article. 
     The unattached carrier  100  further illustrates a circuit arrangement and assembly  134  that includes a carrier  132  and a circuit element  128 . Circuit element  128  in this exemplary embodiment is an electronic circuit formed on a single silicon integrated circuit die. This circuit element  128  of the exemplary embodiment is itself an unpackaged integrated circuit die that is not encapsulated in an insulating material. Further embodiments include encapsulated electronic circuit elements, such as silicone integrated circuits encapsulated in epoxy. Further embodiments include electronic circuits that consist of several integrated circuits, discrete components, and/or other electronic circuit elements. The electronic circuits in some embodiments of the present invention are attached to the carrier  132 . 
     The circuit element  128  of the exemplary embodiment has a number of electrical connection points  136 , as is known by ordinary practitioners in the relevant arts. Each of the electrical connection points  136  in the exemplary embodiment forms a separate electrical connection to the electronic circuitry within the circuit element  128  and has a wire bond connected thereto, such as a first wire bond  118 , a second wire bond  120 , a third wire bond  122  and a fourth wire bond  124 . Each of the wire bonds are connected to a corresponding connection area. The connection areas in the exemplary embodiment are conductive traces deposited on either surface of carrier  132  and are therefore in physical contact with the carrier  132 . The wire bonds place the corresponding connection point ( 136 ) in electrical coupling with a corresponding connection area of the electronic circuit arrangement. The unattached carrier  100  includes of a first conductive trace  110 , a second conductive trace  112 , a third conductive trace  114 , and a fourth conductive trace  116  that are each a connection area. Further embodiments of the present invention use different techniques, such as conductive epoxy, solders, ultrasonic bonding of bumps and other known techniques for direct chip attachment, to electrically connect the electrical connection points  136  on the electronic circuit  128  to the plated traces. It is to be noted that plated traces are able to be made of any conductive trace material. These traces can be plated, etched conductive materials, sputtered, printed, or formed by other means to create an electrically defined conductor. The connection areas in further embodiments of the present invention are embedded into, and therefore in contact with, the carrier of those embodiments, and electrical connections to these connection areas are made by sewing conductive thread through that carrier where the connection areas are located. 
     Carrier  132  of the exemplary embodiment is made of a thin, flexible substrate material. Carrier  132  of the exemplary embodiment is made of a Polyimide flexible circuit substrate. Further embodiments use carriers made of different materials, including but not limited to paper, Mylar, reinforced epoxy or other electrically based dielectric materials. Yet further embodiments use more rigid carriers, such as thin FR4 carriers. Carrier  132  of this exemplary embodiment is able to be sewn through by sewing a thread through the carrier material. When being sewn in such a manner, perforations are formed in the carrier  132  when the thread is passed through the carrier  132 . Such sewing is performed, for example, by common embroidery machines. Conductive threads are sewn through the carrier  132  to form electrical connections, as is described below, and conductive or non-conductive thread are able to be sewn through the carrier  132  to provide physical attachment of the carrier  132 , as well as the circuit assembly  134 , to a textile material  130 . 
     The textile material  130  of the exemplary embodiment has a substrate area  140  that is formed on the surface or within the textile material. A substrate area  140  is used in some, but not all, embodiments of the present invention to provide a more physically stable area onto which the circuit assembly  134  is to be mounted. The substrate area  140  is generally placed in an area proximate, such as adjacent to, an area of the textile material where a carrier  132  is secured to the textile material  130  or a conductive stitching is woven through the carrier  132  and the textile material  130 , as is discussed in more detail below. 
     In further embodiments of the present invention, a substrate area  140 , which can be a plastic coated, fabric, impregnated fabric, or any other surface such as a label, patch, etc., formed on a surface of textile material  130  is itself used as a carrier that is similar to carrier  132 . Using substrate area  140  as a carrier allows further economization of costs and reduction of manufacturing complexity. Some embodiments that use a substrate area  140  as a carrier form connection areas, similar to the first plated trace  110 , onto the substrate area  140  by a metallization process, such as vacuum metallization. Further embodiments of the present invention fabricate carrier  132  directly onto the textile material  130  and do not have a separate substrate area  140 . 
       FIG. 2  illustrates an attached sewn-through carrier  200  according to an exemplary embodiment of the present invention. The attached sewn-through carrier  200  illustrates the configuration of the unattached carrier  100  after electrical connections are formed between the interwoven conductive threads, such as the first conductive thread  102 , and corresponding connection areas of the circuit assembly  134 . The conductive stitching includes a thread that consists entirely or in part of one or more conductive materials, is used in this exemplary embodiment to form these electrical connections. A first conductive stitching  202  connects the first conductive trace  110  and the first conductive thread  102 . The first conductive stitching  202  is a two string stitching as is commonly used for stitching in conventional fabrics. Further embodiments are able to use single thread or multiple thread conductive stitching to form conductive stitching. The first conductive stitching  202  of the exemplary embodiment uses carbon fiber that is sewn through both the carrier  132  and textile material  130  and positioned so as to be in conductive and physical contact with both the first conductive thread  102  and the first conductive trace  110 . This stitching thereby forms a conductive path and electrical connection between the first conductive thread  102  and the first conductive trace  110 . 
     Further embodiments utilize other conductive strings or wires to form conductive stitching. A second conductive stitching  204  similarly forms a conductive contact between the second conductive thread  104  and the second conductive contact  112 , thus creating a separate circuit between the electronic circuit  128  and conductive threads in the textile material  130 . A third conductive stitching  206  and a fourth conductive stitching  208  similarly form independent and electrically isolated contacts between their respective conductive threads and conductive contacts. In addition to the conductive stitching used to form electrical connections with the circuit assembly  134 , further stitching  210 , which can be formed with conductive or non-conductive thread, is able to be used to further mechanically secure the circuit assembly  134 , in particular the carrier  132 , to the textile material  130 . 
       FIG. 3  illustrates an unattached hole-connection carrier  300  according to an exemplary alternative embodiment of the present invention. The unattached hole-connection carrier  300  is similar to the unattached sewn-through connection carrier  100  with the exemption of the structure of the electrical connection between the conductive threads within textile material  330  and the electrical connection points  136  within the electronic circuit  128 . The connection points  136  in this alternative embodiment are connected to the conductive traces with via by wire bonds. Further embodiments connect the connection points to the plated traces with via by other means, such as conductive epoxy, solders, ultrasonic bonding of bumps and other techniques for direct chip attachment. 
     Each of the conductive traces with via, such as the first conducive trace with via  320 , consists of a first conductive trace  340  that is terminated with a pre-formed first conductive, through-hole via  310  that is within the connection area formed by the first conductive trace with via  320 . The first conductive trace  340  of the exemplary alternative embodiment is a conductive trace formed from copper or any conductive trace material, and can be formed as plated, etched conductive materials, sputtered, printed, or through any other technique to create an electrically defined conductor. The first conductive trace  340  is formed on the surface of carrier  332  and is therefore in physical contact with the carrier  332 . Further embodiments incorporate conductive traces that are formed within carrier  332 . The first conductive, through-hole via  310  of the exemplary embodiment is a pre-formed hole within the carrier  332  that is conductive along its walls, and on the top and bottom surfaces. Further embodiments of the present invention have only one of the top and bottom surfaces that consist of conductive material, while the other surface is non-conductive. The first conductive, through-hole via  310  of the exemplary embodiment has conductive pads attaching the hole on each surface of the carrier  332 . Further embodiments have conductive pads on only one surface. The conductive material of the through hole via structure on the surfaces and hole walls facilitates effective electrical connection to the plated trace by threads woven through the hole  310 . 
     The textile material  330  of the exemplary embodiment has conductive threads, such as the first conductive thread  102 , woven therein. The ends of the conductive threads are terminated with button holes, such as the first conductive thread  102  that is terminated with a first button hole  302 . Button holes in the exemplary embodiment are sewn into the textile material  330  with conductive thread that is in physical and conductive contact with one of the conductive threads woven into the textile material. The second conductive thread  104  similarly has a second button hole  304 . The third conductive thread  106  and the fourth conductive thread  108  also have third button hole  306  and a fourth button hole  308 , respectively. 
       FIG. 4  illustrates an attached hole-connection carrier  400  according to the alternative exemplary embodiment of the present invention. The attached hole-connection carrier  400  illustrates that conductive thread is sewn with a button stitch through the conductive, through-hole vias and the button holes so as to form an electrical connection from the conductive threads that are woven into the textile material  330  and the connection points  136  of the electronic circuit  128 . For example, a first button stitch  402  is sewn through by passing a thread through the pre-formed first button hole  302  and the first conductive, through-hole via  310 . The other conductive threads and conductive, through hole vias are physically and electrically connected with other button stitches. It is to be noted that each button stitch is physically isolated from other button stitches and forms a separate connection to a conductive thread woven into the textile material  330 . The button stitches are formed in the exemplary alternative embodiment from carbon thread using button stitching techniques that are familiar to ordinary practitioners in the relevant arts, such as tailoring. The exemplary alternative embodiment further incorporates physical stitching  420 , which can be made from conductive or non-conductive thread, to physically secure the carrier  332  to the textile material  330 . 
       FIG. 5  illustrates a processing flow diagram for implementing a method for connecting two electrical circuits in accordance with the present invention. The processing for this embodiment begins by providing, at step  502 , a carrier, such as carrier  132 , that is able to be sewn through. As discussed above, the carrier  132  has a number of connection areas, such as the first conductive trace  110 , that are in physical contact with the carrier. The processing then places, at step  504 , the carrier, such as carrier  132 , in proximity to a textile material, such as textile material  130 . As discussed above, the textile material has one or more interwoven conductive threads attached to the textile material. The processing then passes, at step  506 , conductive stitching, such as first conductive stitching  202 , through the carrier, such as carrier  132 , and the textile material, such as textile material  130 , so as to form an electrical connection between the connection areas and corresponding interwoven conductive thread. As discussed above, the conductive stitching comprises a conductive material. The processing then determines, at step  508 , if there are more electrical connections to form. If there are more electrical connections to form, the processing returns to passing, at step  506 , conductive stitching to form the next electrical connection. If there are no more electrical connections to form, the processing then terminates. 
     Although specific embodiments of the invention have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing from the spirit and scope of the invention. The scope of the invention is not to be restricted, therefore, to the specific embodiments, and it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present invention.