FIELD OF THE INVENTION

The invention relates to a textile carrier for electrically addressing an electronic component in an electronic textile. The invention further relates to a method for manufacturing the textile carrier, and to an electronic textile comprising the textile carrier.

BACKGROUND OF THE INVENTION

A textile is a material comprised of a network of interlocked fibers known as yarns or threads that can for instance be manufactured by weaving, knitting, crocheting, knotting, or pressing fibers together. Many types of textiles are used in our everyday life. When electronic components are mounted on a textile carrier new application fields emerge.

An electronic component is a device that works by controlling a flow of electrons. An example of an electronic component is a LED package in the form of a surface mounted device (SMD-LED), which can be attached to a textile carrier in a variety of ways. The resulting light-emitting textile could open up a wide range of new interior and apparel applications, ranging from illumination to atmosphere creation to messaging.

When a textile carrier is an integral part of an electrical circuit comprising an electronic component, so that the electronic component is electrically addressable via the textile carrier, an electronic textile is obtained. An electronic component is electrically addressable via the textile carrier when the flow of electrons by which it can be controlled is able to reach the component through an electrode comprised in the textile carrier. Examples are the supply of power and the transmission of data to the electronic component via the electrode comprised in the textile carrier.

For the purpose of electrical addressability, the electronic component has to have an electrically conductive connection to the electrode of the textile carrier. Such a connection can either be direct or indirect, depending on whether or not electrons can flow from the electrode of the textile carrier to the electronic component without having to pass through an electrically conductive intermediate. In an indirect connection electrons have to flow through such an electrically conductive intermediate, while in a direct connection they do not. An example of an electrically conductive intermediate is an electrically conductive adhesive layer, such as a conductive epoxy or solder. From US-7022917-B2 it is known to electrically connect a conductor that is arranged in a textile material to a contact point of an electronic component through application of a solder agent to at least one region of the contact point.

Soldering an electronic component to a textile carrier has to be done at low temperatures. As a result, the solder is more viscous, and therefore flows poorly over contact areas. This means that standard soldering techniques may not be useable for mounting electronic components to a textile carrier. It also means that conventional industrial methods may not be useable. A secondary problem with the low temperatures is that the strength of the solder connection is less than when the connection is established at higher temperatures. As a result, further mechanical strengthening of the electronic components to the textile carrier is required for increasing the long term mechanical reliability of the product.

An example of a direct electrically conductive connection between a textile carrier and an electronic component makes use of a snap button connector. Such a connector is known from WO2008/007237, and has a clamping functionality in order to mechanically fix the direct electrically conductive connection. Drawbacks of a snap button connector are the long term reliability of the mechanical connection to the textile carrier, the increase in the contact resistance of the connection with time, and the overall package size, that prevents electronic textile applications from maintaining a proper textile feel when touched.

Further to an electrically conductive connection between an electronic component and a textile carrier as described above, an electronic textile may also comprise such a connection, for example, between a first textile member and a second textile member, or between a textile member and a non-textile flexible electronic circuit. Particularly for increasing the dimensions of an electronic textile to enable large-area applications, electrically conductive connections between different smaller textile members to constitute a larger textile carrier are desired.

SUMMARY OF THE INVENTION It is an object of the invention to provide a textile carrier for electrically addressing an electronic component in an electronic textile, wherein the textile carrier comprises a textile member to which a direct electrically conductive contact is made that is mechanically robust and that maintains the textile feel of the textile carrier. According to a first aspect of the invention the object is realized by a textile carrier for electrically addressing an electronic component in an electronic textile, the textile carrier comprising a first textile member having a first electrode and a second member having a second electrode, the first electrode having a direct electrically conductive contact to the second electrode, wherein the direct electrically conductive contact is fixed by a welded connection between the first textile member and the second member.

In the context of this invention, a welded connection is a connection between two members, that is obtained by solidifying a liquefied part of at least one of the members, the liquefied part being obtained by locally heating the at least one member to its melting point.

By its nature, the first textile member comprises yarns with a melting point. These yarns can be liquefied when heated up to their melting point. Preferably, the first textile member comprises yarns with a melting point that is equal to or lower than 450 ⁰ C, because such yarns can be conveniently used in a weaving process. Even more preferably, the first textile member comprises yarns with a melting point that is equal to or lower than 300 ⁰ C, such as polyester yarns and polyamide yarns.

In a first embodiment of the textile carrier according to the invention, the second member is a non-textile flexible electronic circuit.

In a second embodiment of the textile carrier according to the invention, the second member is a second textile member. This embodiment enables a large-area textile carrier to be formed based on smaller textile members. An example of such a large-area textile carrier is a textile carrier in the form of a matrix comprising textile ribbons as its rows and columns. Preferably, the first textile member and the second textile member comprise yarns of the same material. The mechanical robustness of a welded connection that is established between the same materials is improved as it is made at a molecular level.

In a third embodiment of the textile carrier according to the invention, the first electrode is an electrically conductive yarn comprising an electrically conductive core and an electrically insulative outer layer. This embodiment enables a direct electrically conductive connection to an otherwise electrically insulated first electrode to be conveniently established.

According to a second aspect of the invention the object is realized by a method for manufacturing a textile carrier for electrically addressing an electronic component in an electronic textile, comprising an alignment step wherein a first textile member comprising a first electrode, and a second member comprising a second electrode are juxtaposed to have the first electrode overlap the second electrode, a heating step wherein a first area of the first textile member and comprising the first electrode is heated to form a first liquefied portion of a yarn, a contacting step wherein the first area of the first textile member is contacted to the second member to form a direct electrically conductive connection between the first electrode and the second electrode, and a fixing step wherein the first liquefied portion is solidified to fix the direct electrically conductive connection between the first electrode and the second electrode.

The method according to the invention establishes a direct electrically conductive connection between the first electrode and the second electrode by liquefying part of one or more yarns comprised in the first textile member. The second member is then brought in contact with this liquefied part, and fixed to the first member by allowing the liquefied part to cool and solidify to result in a mechanically robust welded connection between the first electrode of the first textile member and the second electrode of the second member. During the fixing step, the liquefied part of the first textile member makes a molecular bond with the second member.

Of course, in the method according to the invention the heating step and the contacting step may also be reversed, in that the second member is brought in contact with the first textile member before a part of one or more yarns comprised in the first textile member is liquefied. In a first embodiment of the method according to the invention, pressure is applied during the fixing step. In this case, the electrodes have been brought together in such a way that they are mechanically fixed to each other through pressure exerted by the welded connection. In such a way an electrically conductive contact with improved reliability can be formed in the textile carrier. In a second embodiment of the method according to the invention, in the heating step the first liquefied portion of a yarn is formed by heating the first area of the first textile member to a temperature lower than or equal to 450 ⁰ C. This embodiment has the first textile member comprise yarns that can be liquefied at a temperature of 450 ⁰ C at maximum. Such yarns are particularly advantageous as they can be conveniently used in a standard weaving process. From the point of view of weavability, it would be even more preferred to have the first textile member comprise yarns that can be liquefied at a temperature of 300 ⁰ C at maximum, which is the case for a textile member comprising polyester or polyamide yarns. In a third embodiment of the method according to the invention, the first liquefied portion is formed in an electrically insulative yarn.

In a fourth embodiment of the method according to the invention, the first electrode is an electrically conductive yarn comprising an electrically conductive core and an electrically insulative outer layer, and the first liquefied portion is formed in the electrically insulative outer layer.

In a fifth embodiment of the method according to the invention, the second member is a second textile member. In the heating step of this embodiment a second area of the second textile member and comprising the second electrode is heated to form a second liquefied portion of a yarn, and in the fixing step the second liquefied portion is solidified to further fix the electrically conductive connection between the first electrode and the second electrode.

According to a third aspect of the invention the object is realized by an electronic textile comprising the textile carrier according to the invention, and an electronic component.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which: Fig. 1 shows a part of a textile member that can be used in a textile carrier according to the invention;

Figs. 2(a) to (d) schematically show the manufacture of a textile carrier according to the invention, based on the textile member of Fig. 1;

Figs. 3(a) and (b) schematically show a further textile member that can be used in a textile carrier according to the invention;

Fig. 4 shows a textile carrier according to the invention.

It should be noted that these figures are diagrammatic and not drawn to scale. For the sake of clarity and convenience, relative dimensions and proportions of parts of these figures have been shown exaggerated or reduced in size.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 shows a part of the first textile member 100, comprising yarns that are interwoven in warp and weft directions. One of these interwoven yarns is the electrode 110. The other yarns, such as yarn 120, are electrically insulative yarns made from polyamide. As can be seen in Fig. 1, the electrode 110 is exposed at certain areas of the surface 150 of the first textile member 100. At these exposed areas, the electrode 110 is available for a connection.

Fig. 2(a) also shows a part of the first textile member 100, focusing on the electrode 110 and the electrically insulative yarns 120 and 130, both made from polyamide. For the sake of clarity, the yarns 120 and 130 and the electrode 110 are shown as being parallel and arranged in the same plane. Of course, in reality the yarns 120 and 130 and the electrode 110 would be interwoven into the first textile member 100, as shown in Fig. 1.

In Fig. 2(b), the area 140 of the first textile member 100 has been heated to the melting point of polyamide to form the liquefied portions 121 and 131 of the yarns 120 and 130, respectively. The area 140 comprises part of the electrode 110.

In Fig. 2(c), the second textile member 200 is aligned relative to the first textile member 100, so that the electrode 210 of the second textile member 200 crosses the electrode 110 of the first textile member 100. The part of the second textile member 200 shown in Fig. 2(c) also comprises the electrically insulative yarns 220 and 230, both also made from polyamide, that overlap with the liquefied parts 121 and 131.

In Fig. 2(d), the area 140 of the first textile member 100 has been pressed onto the second textile member 200 to form the direct electrically conductive connection 141 at the interface between the electrode 110 and the electrode 210. Furthermore, the liquefied parts 121 and 131 have been solidified by allowing them to cool so that the direct electrically conductive connection 141 is fixed by the welded connection 142 at the interface between the first textile member 100 and the second textile member 200.

As the yarns 120 and 130 of the first textile member 100, and the yarns 220 and 230 of the second textile member 200 are all made from polyamide, the welded connection 142 is established between the same kind of materials, resulting in a mechanically robust connection at a molecular level.

Fig. 3(a) shows a part of the textile member 300, comprising the electrode 310, and the electrically insulative yarns 320 and 330. The electrode 310 is an electrically conductive yarn comprising the electrically conductive core 311 and the electrically insulative outer layer 312.

In Fig. 3(b), the area 340 comprising part of the electrode 310 of the textile member 300 has been heated to form the liquefied portion 341 that extends over both electrically insulative yarns 320 and 330, and includes part of the outer layer of electrode 310. In a similar way as shown in Figs. 2(c) and (d), a second member comprising a second electrode can be connected to the textile member 300 to form a textile carrier wherein a direct electrically conductive contact is established between the electrode 310 and the second electrode of the second member, and fixed by a welded connection that has been created upon solidifying the liquefied part 341. The concept shown in Figs. 2 and 3 can be extended as shown in Fig. 4, wherein the textile ribbons 410, 420, 430, and 440 have been interconnected to form the textile carrier 400 that has the form of a matrix, and that is suitable for electrically addressing an electronic component in an electronic textile.

Each of the textile ribbons comprises two electrodes, such as the electrodes 411 and 412 comprised in the textile ribbon 410. At each crossing of two textile ribbons, two electrically conductive connections have been formed (shown as black dots in Fig. 3), each between one electrode from each ribbon. For example, at the crossing of the textile ribbons 410 and 430, electrically conductive contacts have been formed between electrodes 411 and 431, and between electrodes 412 and 432, respectively. These two electrically conductive contacts are fixed by the welded connection 413, that connects the textile ribbons 410 and 430. At each of the other crossings in the textile carrier 400, similar welded connections exist.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.