VAN PIETERSON, Liesbeth (AE Eindhoven, NL-5656, NL)
BHATTACHARYA, Rabin (AE Eindhoven, NL-5656, NL)
VAN PIETERSON, Liesbeth (AE Eindhoven, NL-5656, NL)
CLAIMS:
1. A method for manufacturing a textile having a conductor pattern (200, 402) for connection of electronic components thereto, the method comprising the steps of: providing (301) a textile substrate (220, 401) with a continuous electrode (400) which is divisible to form the conductor pattern (200, 402) by cutting the textile, - applying (302) a metal layer (405) to the continuous electrode (400) by means of electro-plating, and cutting (303) the textile to form the conductor pattern (200, 402).
2. The method according to claim 1, wherein the continuous electrode (400) comprises: the conductor pattern (402), and a connecting portion (403) connecting electrically separated portions of the conductor pattern.
3. The method according to claim 2, wherein the connecting portion (403) is positioned outside the conductor pattern (402).
4. The method according to claim 2 or 3, wherein the connecting portion (403) is separable from the conductor pattern (402) through a cut along a continuous line (404).
5. The method according to any one of the preceding claims, wherein the textile substrate (220, 401) is provided with the continuous electrode (400) by using conductive fibers in the warp and weft direction during manufacturing of the textile substrate (220, 401).
6. The method according to any one of the preceding claims, wherein the continuous electrode (400) is applied by means of printing droplets of a conductive substance.
7. A textile for enabling connection of electronic components, comprising: a textile substrate (220), and a multi-layer conductor pattern (200) including a plurality of electrically separated conductors (206a-h) formed on the textile substrate (220), each of the conductors leading to a cut edge of the textile.
8. An electronic textile comprising: the textile according to claim 7, and at least one electronic component connected to the conductor pattern. |
Textile for connection of electronic devices and manufacturing method therefore
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a textile having a conductor pattern for connection of electronic components thereto, and to a method for manufacturing such a textile.
TECHNICAL BACKGROUND
Currently, research in the field of electronic textiles is very active, and although not a great deal of advanced electronic textile products can be found in the marketplace today, it is expected that many new products will find their way to the consumers in the near future.
A developer of an advanced electronic textile has to provide the textile with a conductor pattern for feeding and interconnecting electronic components to be comprised in the electronic textile.
A known method for providing a textile with a conductor pattern is disclosed in US 2003/0211797. In the known method, the conductor pattern is formed by using electrically-conductive fibers in the warp and weft direction during manufacturing of the textile, wherein the electrically-conductive fibers are metal-coated polymer strands.
A problem of the known method is the poor conductivity of the metal-coated polymer strands. According to the known method, metal threads can also be used as electrically-conductive fibers. However, such metal threads are fragile and break easily during the weaving process.
SUMMARY OF THE INVENTION
In view of the above-mentioned and other drawbacks of the prior art, a general object of the present invention is to provide an improved method for manufacturing a textile having a conductor pattern for connection of electronic components thereto.
According to a first aspect of the present invention, these and other objects are achieved through a method for manufacturing a textile having a conductor pattern for connection of electronic components thereto, comprising the steps of providing a textile
substrate with a continuous electrode which is divisible to form the conductor pattern by cutting the textile, applying a metal layer to the continuous electrode by means of electroplating, and cutting the textile to form the conductor pattern.
By "textile" should, in the context of the present application, be understood a material or product manufactured by textile fibers. The textile may, for example, be manufactured by means of weaving, braiding, knitting, or felting. In particular, a textile may be woven or non- woven.
The "continuous electrode" may have any physical shape, given that it forms a single electrically conductive structure. The textile substrate may be provided with the continuous electrode in any suitable manner. In a first example, a matrix of rows and columns is provided in the textile substrate by using conductive yarn in the warp and weft direction during manufacturing of the textile substrate. The rows and columns of the matrix can subsequently be short-circuited to form the continuous electrode. In a second example, the continuous electrode is applied on the textile substrate by a printing technique, such as screen printing, ink-jet printing, tampon printing, pad printing, stamp printing, and offset printing.
By "electro -plating" should be understood a method of applying a metal by means of electrolysis.
The present invention is based upon the realization that a textile substrate can be provided with a conductor pattern having desirable electrical and/or mechanical properties by applying a metal layer to a preformed conductor pattern.
The inventors have further realized that this can be accomplished by providing the textile substrate with a continuous electrode comprising the desired conductor pattern, coating this continuous electrode by means of electrodeposition of a metal layer and, finally, cutting the textile to disconnect the individual connectors from each other, whereby the desired conductor pattern is achieved.
Through the invention, the geometry of a conductor pattern can be achieved with a technique which is suitable for defining a geometry, the only restriction being that the geometry formed should be capable of conducting electric current to a sufficient degree. Subsequently, the desired electrical and/or physical properties of the conductor pattern can be achieved by electro-plating the previously defined geometry with one or several metal layers.
The choice of metals and the applied thickness of individual layers thereof may be determined by requirements on properties such as electric conductivity, thermal conductivity, mechanical strength, resistance to corrosion etc.
The continuous electrode may advantageously comprise the conductor pattern, and a connecting portion connecting electrically separated portions of the conductor pattern. The continuous electrode may include one or several connecting portions. In the case of several connecting portions, each connecting portion typically serves to electrically connect a group of conductors in the conductor pattern which are to be electrically separated in a subsequent step.
Hereby, the number and complexity of the cuts required to divide the continuous electrode to form the conductor pattern is reduced, facilitating the subsequent formation of the conductor pattern. Furthermore, the connecting portion may preferably be positioned outside the conductor pattern.
By forming the continuous electrode in such a way that a connecting portion is positioned outside the conductor pattern, the cutting step can be further simplified.
Additionally, the connecting portion may be separable from the conductor pattern through a cut along a continuous line, whereby the cutting process is further facilitated.
An additional advantage of the method according to the invention is that it can decrease the sensitivty towards corrosion in air of the conductor pattern, a problem that particularly occurs when the conductor pattern comprises silver-coated polymer strands as electrically-conductive fibers.
Another known method for providing a textile with a conductor pattern is disclosed in US 2005/0260350, wherein a conductor pattern is formed on the face of a substrate by means of electro less deposition. According to this method, the conductor pattern is first formed using a suspension of special colloid particles which can catalyze electroless deposition. Thereafter, electroless deposition of a metal substance on the pattern is performed to form the conductor pattern.
A drawback of this method is that it requires the formation of a pattern by means of a solution including colloid particles, such as Palladium nanoparticles, having special properties. This limits the available application methods, and may also lead to a cost disadvantage, especially for large area conductor patterns.
According to a first embodiment of the method according to the invention, the textile substrate is provided with the continuous electrode by using electrically-conductive fibers in the warp and weft direction during manufacturing of the textile substrate.
In this embodiment, a conductor pattern with a desired conductivity is obtained by using electrically-conductive fibers having an initial conductivity (i.e. a conductivity prior to electro -plating) that is sufficient to allow electro-plating of the fibers in order to adjust their conductivity to the desired level. This embodiment therefore poses only moderate requirements on the type of electrically-conductive fibers that can be used. An additional advantage of this embodiment is that the electro -plating process fuses together an electrically-conductive connection that exists at a crossing between two electrically- conductive fibers in a warp and weft direction, respectively, thereby increasing the mechanical robustness of such a connection, and of the conductor pattern as a whole. According to a second embodiment of the method according to the invention, the continuous electrode is applied by means of printing droplets of a conductive substance. In this embodiment, the textile substrate should preferably be mainly non-conductive, at least on a top surface thereof to avoid short-circuiting the conductor pattern formed thereon. Conductive inks currently available for various types of so-called ink-jet printers have suitable properties for forming the continuous electrode, but not for directly forming a conductor pattern suitable for mounting of electronic components in a number of applications. However, the relatively low cost of ink-jet printers, their wide-spread availability and their ability to print small and exact features make droplet-based marking a favorable method for applying the continuous electrode. As an alternative to droplet-based printing, the continuous electrode could be applied by other types of printing methods, such as electrophotography or direct powder printing.
According to a second aspect of the present invention, the above-mentioned and other objects are achieved through a textile for enabling connection of electronic components, comprising a textile substrate, and a multi-layer conductor pattern including a plurality of electrically-separated conductors, each of the conductors leading to a cut edge of the textile.
In the above case, the textile may be a multi-layer woven textile with at least a lower and an upper warp layer and interwoven conductive and non-conductive weft yarns, in which a particular conductive weft yarn may traverse between bottom and top surfaces of the textile substrate to form loops around warp yarns in the lower and upper warp layers.
By forming the conductor pattern as a multi-layer conductor pattern, a first substance and/or application technology especially suitable therefore can be used for defining the pattern in the first layer, and a second substance and/or application technology providing
desired electrical and/or mechanical properties to the resultant multi-layer conductor pattern can be applied to cover the first substance.
Further effects and features of the present second aspect of the invention are largely analogous to those described above in connection with the embodiments. Preferably, both the first and the second layers are conductive, and the conductive property of the first layer is used to enable application of the second layer.
Any subsequent layers may be conductive or non-conductive depending on the requirements of the specific application.
Each of the plurality of conductors in the conductor pattern may, furthermore, include a pre-formed conductive structure having a metal layer formed thereon.
The metal layer may entirely cover a portion of a conductor cross-section boundary not facing the textile substrate.
Typically, in a cross-section perpendicular to a principal extension of a conductor, a bottom side of the conductor will face the textile substrate, and an opposing top side and left and right edges will be covered by the applied metal layer. Depending on by what means the pre-formed conductive structure is applied, it may be so thin that its edges, in cross-section, will be minute. The above should then be understood to mean that the entire portion of the boundary of the cross-section not facing the textile substrate is covered by the metal layer. Moreover, the textile according to the present invention may advantageously be included in an electronic textile, further comprising a at least one electronic device connected to the conductor pattern on the textile.
BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing a currently preferred embodiment of the invention, wherein:
Fig. 1 is a circuit diagram for an exemplary electronic textile; Figs. 2a-c schematically shows an embodiment of a textile according to the present invention having a multi-layer conductor pattern corresponding to the circuit diagram in Fig. 1;
Fig. 3 is a flow chart schematically illustrating a method for forming the multilayer conductor pattern in Fig. 2;
Figs. 4a-c schematically illustrate the multi-layer conductor pattern formed according to the method of Fig. 3 in states following the corresponding method steps; and
Figs. 5a-b schematically illustrate exemplary ways of performing the corresponding steps of the method according to Fig. 3.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
In the following description, the present invention is described with reference to an exemplary electronic textile having a simplified circuit pattern and a single electronic device connected thereto. It should be noted that this by no means limits the scope of the invention, which is equally applicable to textiles having a more complex conductor pattern for enabling connection of a plurality of electronic device.
Furthermore, although single exemplary ways of performing the respective steps of the method according to the invention are described herein, the skilled person would readily be able to perform these steps by means of equivalent techniques known in the art.
In Fig. 1, which is a schematic circuit diagram for an exemplary electronic textile, a circuit pattern 100 is shown for connecting an electronic component 101 having eight terminals 102a-h with proper terminals 103a-g of a connector 104.
As shown in Fig. 1, the terminals 102f and 102h of the electronic component 101 are connected to each other, leading to a circuit pattern 100 having crossing conductors.
Fig. 2a is a front view from the top schematically showing a textile according to an embodiment of the present invention having a multi-layer conductor pattern 200 provided on a textile substrate 220, corresponding to the exemplary circuit diagram in Fig. 1.
The multi-layer conductor pattern 200 includes, as shown in Fig. 2a, connecting pads 201a-h corresponding to the terminals 101a-h of the electronic component 102 in Fig. 1, and connecting pads 202a-g corresponding to the terminals 103a-g of the connector 104 in Fig. 1. Furthermore, the conductor pattern 200 comprises a metal heat sink 203 for dissipating heat generated by the electronic component 102 when in operation.
As can also be seen in Fig. 2a, each of the mutually electrically separated structures in the conductor pattern 200 leads to an edge 204 of the textile. The reason for this will be evident from the description provided in connection to the flow chart in Fig. 3.
The interconnection between the pads 20 If and 20 Ih for enabling short- circuiting of the corresponding terminals 101 f and 10 Ih of the electronic component 102 in Fig. 1 is, in the present exemplary embodiment, achieved by a conductive weft yarn 205
which interconnects the conductors 206f and 206h leading to the pads 20 If and 20 Ih, respectively.
With reference to Fig. 2b, which is a schematic cross-section view of a section taken along the line A-A' in Fig. 2a, the conductive weft yarn 205 is shown to, at a location corresponding to the first conductor 206f, form a first loop 207 from a bottom side 208 to a top side 209 of the textile and back again enclosing a non-conductive warp yarn in each of the two warp layers 210 and 211 of the exemplary woven textile substrate 220, and then a second loop 212, at a location corresponding to the conductor 206h to be interconnected with the first conductor 206f. Between the two loops 207, 212, the conductive weft yarn 205 passes on the bottom side 208 of the textile substrate 220 so that it crosses the conductor 206g on the top side 209 of the textile substrate 220.
In order to achieve the application-specific requirements with respect to such parameters as thermal conductivity, electrical conductivity, corrosion resistance, etc, the conductor pattern in Fig. 2a is provided in several layers. As can be seen in Fig. 2c showing a cross-section of the textile in Fig. 2a along the line B-B', the conductor 206h (as well as the other conductors in the conductor pattern 200) are comprised of a conductor structure 230 which is preformed on the textile substrate 220 as will be described in further detail below, and a metal layer 231 covering all sides of the conductor structure 230 except the one facing the textile substrate 220. In such a structure, the conductor structure 230 can be formed by an application method and substance which is particularly suitable for forming a conductive pattern on a textile substrate. Other physical properties, such as thermal conductivity, corrosion resistance etc, are typically not important for this conductor structure. Subsequently, the fact that the conductor structure 230 is electrically conductive can be used to apply the metal layer 231 coating the conductor structure. Since this metal layer 231 is applied by using the previously applied conductor structure 230 as a guiding structure, the metal layer 231 need not be applied using an application method and/or substance which can by itself form a pattern on the textile substrate 230. Instead, the other requirements on the conductor pattern 200, such as electric and thermal conductivity, and/or corrosion resistance can be focused on.
An exemplary method according to an embodiment of the present invention for forming the conductor pattern 220 in Fig. 2 will now be described with reference to the flow-chart in Fig. 3, the schematic illustrations of intermediate states of the conductor
structure 220 provided in Figs. 4a-c, and the schematic illustrations of exemplary ways of performing the corresponding steps provided in Fig. 5a-b.
With reference to Fig. 3 and Fig. 4a, a textile substrate 401 is provided with a continuous electrode 400 in a first step 301. As discussed above, the main requirements on the application method and/or substance for the continuous electrode 400 are that it/they should be suitable for application on a textile substrate and that the resultant continuous electrode should have a sufficiently high electric conductivity to enable the subsequent electro-plating process. An example of a suitable application method is schematically illustrated in Fig. 5a, showing a schematic ink-jet print head 500 by means of which the continuous electrode 400 is printed on the textile substrate 401. Any conductive ink capable of forming a continuous electrode having a sufficiently high electric conductivity may be used together with a correspondingly configured ink-jet print head 500. For example, the ink may be based on a metal which can be printed at low temperatures, such as silver.
Alternatively, the continuous electrode 400 may, for example, be formed by interweaving electrically-conductive fibers during manufacturing, or by means of screen printing, tampon printing, or any other suitable method known to the skilled person (the only requirements being the above mentioned).
Referring again to Fig. 4a, the continuous electrode 400 comprises a conductor pattern 402 and a connecting portion 403, connecting the electrically separated portions of the conductor pattern 402. As can be seen in Fig. 4a, the connecting portion 403 is positioned outside the conductor pattern 402 and is arranged in such a way that it can be separated from the conductor pattern 402 by a single cut through the textile along the dashed line indicated by the numeral 404 in Fig. 4a.
Moving on to the next step 302 in Fig. 3, the continuous electrode 400 is electro-plated to form a metal layer covering the continuous electrode 400. Hereby, as shown in Fig. 4b, the first formed conductor structure 400 is covered by a metal layer 405 on all exposed sides thereof.
In Fig. 5b, the textile substrate 401, having the continuous electrode 400 formed thereon, is shown immersed in a solution 509 containing ions of the desired metal to be electroplated. In accordance with the well-known principle of electro-deposition, the negative terminal 510 of a voltage source 511 is connected to a cathode constituted by the continuous electrode 400, and the positive terminal 512 is connected to an anode 513. By inducing a negative charge on the surface of the continuous electrode 400, metal ions are attracted thereto, accept the sufficient number of electrons and transcend to their metal state,
whereby a metal layer is formed on the surface of the continuous electrode 400. The anode 513 may be made of the metal to be applied to the continuous electrode 400, or may be a so- called non-consumable anode, in which case the metal ions may need to be replenished in the solution 509 during deposition. Finally, in step 303, the continuous electrode 400 and the textile substrate 401 are cut along the line 404 to separate the conductor pattern 402 from the connecting portion 403 of the continuous electrode 400.
Hereby, a textile having the conductor structure shown in Figs. 2a-c has been realized, whereby an electronic textile according to the circuit diagram in Fig. 1 can be manufactured.
The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. For example, the continuous electrode may have several connecting portions which may be positioned embedded in, as well as outside the conductor pattern.