WO2003050832A1

WO2003050832A1 - Flexible textile structure for producing electric switches

Info

Publication number: WO2003050832A1
Application number: PCT/FR2002/004188
Authority: WO
Inventors: Emmanuel Deflin; André Weill; Jacques Bonfiglio; Bénédicte ATHIMON-PILLARD
Original assignee: France Telecom
Priority date: 2001-12-12
Filing date: 2002-12-05
Publication date: 2003-06-19
Also published as: FR2833403A1; FR2833403B1; AU2002361434A1

Abstract

The invention concerns a flexible textile structures for producing electric switches, comprising: a first electrically insulating fabric (2) including holes; a second electrically conductive fabric (1, 5) arranged against one first surface of said first fabric; a third electrically conductive fabric (3, 11) arranged against a second surface of said first fabric, such that a pressure exerted on one surface of said textile structure urges into contact the second and third fabrics through one or several holes of the first fabric beneath said surface.

Description

Soft textile structure for making electrical switches.

The field of the invention is that of textiles for clothing, for example clothing. The envisaged applications relate to all electronic devices, portable or not, requiring a button or keyboard type control interface, taking into account new ergonomic needs in terms of flexibility, finesse and reduction in weight.

More specifically, this new technology was originally developed for communicating clothing, with the aim of integrating communicating electronic control buttons worn on oneself into textile structures.

The integration of electronic systems in clothing creates new needs with regard to control interfaces. In addition to voice recognition or sensor-based systems linked to gestures, new simple button or keyboard actuator technologies are emerging. These so-called textile actuator technologies are essentially based on at least one electrically conductive textile component (fiber, thread or even printing on fabric) and require notably sophisticated electronics for interpreting commands. For example, patent application WO 0079 546 exploits a variation in electrical resistance in a composite structure based on a conductive fiber net embedded in a polymer matrix. An active electronic system is required to interpret and translate a physical command action. The system analyzes a pressure intensity applied to the keyboard by interpretation of a variation in the electrical resistance of the structure, so as to trigger this or that command. Such a technique can prove to be too complex and too costly for many all-or-nothing switch type applications, such as on / off buttons. In the publication E. Rehmi Post and Magic Orth, "Smart Fabric.or

Washable Computing ", First I.EE. International Symposium on Wearable Computers, October 13-14, 1997, a keyboard uses electrodes embroidered on a fabric with a conductive stainless steel wire. The contact of the fingers on these electrodes causes a capacitive variation exploited by an auxiliary electronic system. Friction and shock in clothing related to the physical activity of the user can trigger commands inadvertently because of the high sensitivity of such a control interface. There are also control buttons printed on fabric using conductive ink. The fragile structure and the materials that make up the textile control interface do not allow for classic clothing maintenance. Integration of this textile interface into clothing or any other structure poses washing problems linked to the resistance to wear and to the oxidation of certain materials.

To improve the known state of the art and remedy the aforementioned drawbacks, a first object of the invention is a textile structure for producing an electrical switch which offers the flexibility of a fine fabric with reduced weight and volumes.

A second object of the invention is to facilitate manufacturing and to reduce production costs for simple electronic orders. A third object of the invention is to be able to design and produce the textile structure by following methods specific to textile confection which facilitates integration into the production circuit of a garment.

A fourth object of the invention is to reduce the problems of untimely triggering linked to the mechanical stresses which clothing undergoes. A fifth object of the invention is a structure. textile which offers good resistance to washing.

The textile structure according to the invention is remarkable in that it comprises a first electrically insulating fabric comprising holes, a second electrically conductive fabric disposed against a first face of said first fabric, a third electrically conductive fabric disposed against a second face of said first canvas. The superposition of fabrics retains the flexibility of the textile structure. In this way, a pressure exerted on a surface of said textile structure, brings the second and third fabrics into contact through one or more holes of said first fabric under said surface. The coming into contact of the two electrically conductive fabrics through the holes under the effect of a pressure, and the separation of the two electrically conductive fabrics by the electrically insulating fabric in the absence of pressure, allows an electrical switch to be produced.

Advantageously, the second fabric is electrically conductive in strips that are parallel to each other, the third fabric is electrically conductive in strips that are parallel to each other and perpendicular to the strips of the second fabric.

Pressure exerted on a crossover point of the strip of the second fabric and of the strip of the third fabric makes it possible to bring two electrically conductive strips into contact through the holes in the first fabric.

Advantageously also, the flexible textile structure comprises a fourth electrically insulating fabric comprising at least one hole with an area greater than one or more holes of said first fabric, said fourth fabric being disposed between the second and third fabric.

Thus, the non-drilled parts of the fourth fabric prevent the second and third fabrics from coming into contact through the holes in the first fabric. The possible contacts are limited to the hole in the fourth canvas. This is advantageous for the assembly of textile parts of structures in accordance with the invention. The non-pierced part of the fourth fabric makes it possible to fix the parts together by sewing or by cold welding, without bringing the second fabric into contact with the third fabric of each part.

In particular, the second or third fabric comprises metallic wires. The electrical conductivity of the second or third fabric is then linked to the electrical conductivity of these metal wires. More particularly, and differently, the second or third fabric is impregnated with an electrically conductive ink. It is then the electrical conductivity of the ink which gives the second or third canvas its properties of electrical conductivity. Particularly and still differently, the second or third fabric comprises metallic particles of sufficient density to provide electrical conduction.

An additional advantage is obtained by a fifth electrically uniformly insulating fabric disposed on one face of the second or third fabric opposite to a face against the first fabric.

The insulation of the external face of the second or third fabric which results from this arrangement makes it possible to avoid leakage currents towards an external body brought into contact with the textile structure, for example to exert pressure thereon. More particularly then, a descriptive element is placed on a visible face of the fifth fabric.

This identifying element marks on the textile structure, a privileged point of contact for exerting pressure.

Whatever the embodiment of the flexible textile structure, an electrical terminal connected to the second fabric and an electrical terminal connected to the third fabric, allow the use of an electrical switch provided by this textile structure, in an electrical circuit.

The invention will be better understood in the examples of implementation, the description of which follows with reference to the appended drawings in which: - Figure 1 is an exploded view of a textile structure according to the invention, Figure 2 is an exploded view of improved textile structure according to the invention, FIG. 3 is an exploded view of a textile structure according to the invention particularly suitable for making clothes. Referring to Figure 1, a flexible textile structure includes three superimposed fabrics. A first fabric 2, electrically insulating, includes holes. The fabric 2 is for example a flexible grid of polymer material. For example again, the fabric 2 is a fabric of the "thulle" type, that is to say a fabric in which the warp threads are spaced. Square holes are then caused by spacing of the weft threads. The warp and weft threads are electrically insulating, such as for example wool, cotton or synthetic fiber threads.

Fabrics 1 and 3 are electrically conductive fabrics. Various embodiments of the conductive fabric can be used. According to a first embodiment, the electrically conductive fabric is produced by weaving metallic wires. According to a second embodiment, the electrically conductive fabric is produced by plasma deposition of metal particles on a textile substrate. The metal particles are deposited in sufficient density to ensure permanent and constant electrical conduction. According to a third embodiment, the electrically conductive fabric consists of any fabric impregnated with an electrically conductive ink. Garments are often subjected to chemical attacks by external agents, for example during washing or by exposure to bad weather. For good resistance over time of the conductive fabric, the metals used should be stainless. It is possible, for example, to use copper coated with a layer of nickel or stainless steel when the electrical conduction properties of the steel are satisfactory. Figure 1 is an exploded view of the flexible textile structure. That is to say that the three canvases 1, 2, 3 are shown separated one above the other so as to simply highlight them better. In fact, the fabric 1 is arranged against a first face of the fabric 2, here the upper face. The fabric 3 is arranged against a second face of the fabric 2, here the underside. A spacing between the fabrics 1 and 3 is substantially at most equal to the thickness of the fabric 2. In the absence of particular constraints, the fabric 1 is electrically isolated from the fabric 3 by the fabric 2. When pressure is exerted on a surface of the textile structure, the fabric 1 is brought into contact with the fabric 3 through one or more holes in the fabric 2 under said surface . The pressure can result from a pressing force on the fabric 1 when the fabric 3 is placed against a rigid support 4. On the surface of the fabric 1 subjected to the supporting force, the fabric 1 deforms to penetrate through the holes in the fabric 2. For example again, the pressure results from a pinching force applied to a surface of the textile structure by the two fingers of one hand, one finger pressing on the fabric 1 and the other finger pressing in the same place in the opposite direction on the fabric 3. The contacting of the fabrics 1 and 3 through the holes of the fabric 2 is facilitated by an elastic crushing of the fibers constituting the fabric 2. The contact of the fabrics 1 and 3 provides zero electrical resistance in the manner of a closed electrical switch. When the pressure is released, the fabrics 1 and 3 return to their initial position separated by the fabric 2, in the manner of an open electrical switch.

The sensitivity of the electrical contact is adjusted by taking the following elements into account during the production of the textile structure. The smaller the surface of the holes, the lower the sensitivity because the fabrics 1 and 3 require high pressure to deform and come into contact through the holes. Conversely, the larger the surface of the holes, the higher the sensitivity. The higher the thickness of the fabric 2, the lower the sensitivity because a more substantial deformation of the fabrics 1 and 3 is necessary to put these two fabrics in contact through the holes in the fabric 2. Conversely, more the thickness of the fabric 2 is small, the higher the sensitivity. The lower the flexibility of the fabrics 1 and 3, the lower the sensitivity because the fabrics 1 and 3 then require high pressure to be deformed. Conversely, the greater the flexibility of fabrics 1 and 3, the greater the sensitivity. A poor quality of the surface condition of the fabrics 1 and 3 gives a high sensitivity because the roughness of the faces of the fabrics 1 and 3 facing through the holes of the fabric 2, reduce the distance to be traveled in a hole during deformation fabrics 1 or 3. Conversely, good quality of the surface condition of fabrics 1 and 3 weakens the sensitivity because bringing the fabrics 1 and 3 into contact through a hole in the fabric 2 requires sufficient deformation to cover the entire thickness of the fabric 2.

Various known methods of the textile industry can be used to assemble the described textile structure. Mention may be made, by way of nonlimiting example, of sewing or cold welding. The fabrics 1 and 3 should therefore not be accidentally brought into contact by the assembly method used.

With reference to FIG. 3, an assembly element 9 is disposed between the fabric 2 and the fabric 3. Either the assembly element 9 can be disposed between the fabric 1 and the fabric 2. Advantageously, the element of assembly 9 is an electrically insulating fabric comprising at least one hole with an area greater than one or more holes in the fabric 2. Thus the fabric 1 can only be brought into contact through the holes in the fabric 2 with the fabric 3, only on a surface corresponding to the holes in the fabric 9.

On the non-pierced part of the fabric 9, a deformation of the fabric 1 to bring it closer to the fabric 3 through one or more holes in the fabric 2, puts the fabric 1 in contact with the fabric 9 which is electrically insulating. Thus, permanent pressure exerted on either side of the textile structure on a surface element for which the fabric 9 constitutes an insulating separation between the fabric 1 and the fabric 3, avoids any electrical contact between the fabric 1 and the fabric 3 It is then possible to produce an assembly line 10 for the fabrics 1 and 3 in correspondence with the non-pierced part of the fabric 9 which provides electrical insulation. Here again, a rigid support 4 can be made to adhere to the underside of the fabric 3. The rigid support 4 is for example a plate of dimensions substantially equal to the hole in the fabric 9.

In Figure 2 we find the electrically insulating fabric 2. A fabric 5, electrically conductive in strips which are parallel to each other, is placed against the upper face of the fabric 2. According to a first embodiment of the fabric 5, strips 6, 14, 15 are cut from a material identical to that of the fabric 1. These bands 6, 14, 15 are arranged in parallel in a first direction, on the upper face of the fabric 2. According to a second embodiment, the fabric 5 is generally insulating and the bands 6 , 14, 15 are printed on the face of the fabric 5 in contact with the fabric 2, in parallel in the first direction.

A fabric 11, electrically conductive in strips which are parallel to each other and perpendicular to the bands 6, 14, 15, is disposed against the underside of the fabric 2. According to a first embodiment, bands 16, 17, 13 are cut in an electrically conductive material, identical to that of the fabric 3. The strips 16, 17, 18 are arranged in parallel against the underside of the fabric 2, in a second direction perpendicular to the first direction. According to a second embodiment, the strips 16, 17, 18, are printed by means of an electrically conductive ink, on a face disposed against the fabric 2, of a generally insulating fabric 11.

A fabric 7, electrically uniformly insulating, is disposed over the strips 6, 14, 15. Signs 8 are arranged on a visible face of the cloth 7. Each sign 8 is located on a cross of a strip 6, 14, 15 with a strip 16, 17, 18. In the example of FIG. 2, the identifying element marked A corresponds to the crossing of the strip 15 with the strip 16. The identifying element marked B corresponds to the crossing of the strip 14 with the strip 16. The descriptive element marked C corresponds to the crossing of strip 6 with the strip 16. The descriptive element marked D corresponds to the crossing of strip 15 with the strip 17. The descriptive element marked E corresponds at the crossing of the strip 14 with the strip 17. The identifying element marked F corresponds to the crossing of the strip 6 with the strip 17. The identifying element marked G corresponds to the crossing of the strip 15 with the strip 18. The element signage marked H corresponds to the crossing of strip 14 with strip 18. The descriptive element marked I corresponds to the crossing of strip 6 with strip Thus, a bearing force exerted on the sign marked C deforms the strip 6 to bring it into contact with the strip 16 through the holes in the fabric 2 under the sign marked C, A bearing force exerted on the identification element marked F, deforms the strip 6 so as to bring it into contact with the strip 17 through the holes in the fabric 2 located under the identification element marked F. A pressing force exerted on the identified identification element I, deforms the strip 6 in order to bring it into contact with the strip 18 through the holes in the fabric 2 located under the identified descriptive element I. It is noted that the nine descriptive elements represented in FIG. 2 make it possible to achieve a combination of nine separate contacts of the strips 6, 14, 15 with the strips 16, 17, 18. Assembly, the textile structure shown in FIG. 2, produces a keyboard with nine keys. The force, of pressing on the descriptive element marked C for example, can be done by pinching between two fingers above the strip 6 and below the strip 16. By placing the strips 16, 17, 18 on a rigid support 4, it then suffices to press on the strip 6 which compresses the textile structure against the rigid support 4.

Differently, in the absence of a rigid support 4 for bringing the strip 6 into contact with the strip 18, it suffices to apply a pinch on the crossing point of these two strips by pressing with a finger on the descriptive element marked I and keeping the other finger pressed against the textile structure under the identifying element marked I.

An electrical terminal 12 is connected to the strip 6 to allow the strip 6 to be connected to an electrical circuit by means of a conductor. This conductor, not shown, is for example an electric wire or a track printed on an insulating part of the fabric by means of an electrically conductive ink. An electrical terminal 13 is connected to the strip 18 to allow connection to this electrical circuit, not shown. The electrical terminals 12 and 13 are for example conventional haberdashery accessories that conduct electricity such as press studs or metal fasteners. Similarly, electrical terminals not shown are connected on the strips 14, 15 and on the strips 16, 17 to allow a connection of electrical conductors to the electrical circuit. Thus, it is possible to send commands to the electrical circuit by pressing on one of the descriptive elements 8 which turns on a strip 6, 14, 15 with a strip 16, 17, 18 through a hole in the strip 2.

Claims

1. Flexible textile structure for producing electrical switches, characterized in that it comprises: - a first electrically insulating fabric (2) comprising holes,

- a second electrically conductive fabric (1,5) disposed against a first face of said first fabric,

- a third electrically conductive fabric (3,11) disposed against a second face of said first fabric, so that a pressure exerted on a surface of said textile structure, brings the second and third fabric into contact through one or more holes of said first fabric under said surface.

2. flexible textile structure according to claim 1, characterized in that: - the second fabric (5) is electrically conductive by strips (6) parallel to each other,

- The third fabric (11) is electrically conductive by strips (16) parallel to each other and perpendicular to the strips of the second fabric.

3 flexible textile structure according to claim 1 or 2, characterized in that it comprises a fourth electrically insulating fabric (9) comprising at least one hole with an area greater than one or more holes of said first fabric (2), said fourth fabric (9) being disposed between the second and the third fabric.

4. Flexible textile structure according to one of the preceding claims, characterized in that at least one of the second and third fabrics comprises metallic threads.

5. flexible textile structure according to one of claims 1 to 3, characterized in that at least one of the second and the third fabric is impregnated with an electrically conductive ink.

6. flexible textile structure according to one of claims 1 to 3, characterized in that at least one of the second and the third fabric comprises metallic particles of sufficient density to ensure electrical conduction.

7. flexible textile structure according to claim 3, characterized in that it comprises a fifth fabric (7) electrically uniformly insulating disposed on one side of the second or third fabric, opposite to one side against the first fabric (2) .

8. flexible textile structure according to claim 7, characterized in that at least one sign (8) is disposed on a visible face of the fifth fabric.

9. flexible textile structure according to one of the preceding claims, characterized in that at least one electrical terminal (12) is connected to the second fabric (1,5) and at least one electrical terminal (13) is connected to the third canvas (3.11).