FIELD OF THE INVENTION

The present invention relates to an electronic textile comprising a textile member comprising a textile electrode, and an electronic component arranged in connection to the textile member and electrically addressable via the textile electrode.

BACKGROUND OF THE INVENTION

Functional materials may be utilized to improve the performance of a product. One class of functional materials are chromic materials which comprise a compound that employs a process in which a reversible change in the color of the compound is induced by subjecting the material to an external stimulus capable of activating the chromic effect. In most cases, the chromic effect is based on a change in the electron states of molecules, especially the π- or d-electron state. The change in color may thus be induced by various external stimuli capable of altering the electron density of substances.

Today it is known that there are many natural compounds that have chromic behavior. However, in addition many artificial compounds with specific chromic behavior have been synthesized to date. The different kinds of stimuli used to induce color change in a chromic compound is also used to classify the phenomenon: heat corresponds to a thermochromic effect, light radiation corresponds to a photochromic effect, electrical current corresponds to an electrochromic effect, magnetic fields correspond to a magnetochromic effect, and the prescence of ions corresponds to an ionochromic effect. Depending upon the chromic compound used, different phenomena may be activated in the material when it is subjected to an external stimulus, like reversible color change, absorption and reflection of light, or luminescence.

It is known to apply a chromic compound in a textile material. This may be achieved by utilizing organic dyes or pigments that comprise chromic compounds. A thermochromic textile material is disclosed in U.S. Patent No. 4,681,791. The textile material, in the form of fiber, raw stock, yarn or fabric, comprises fibers which are coated with a thermocromic layer containing a thermochromic pigment. The textile material can undergo reversible color change with temperature in a wide variety of colors. Another way of improving the functionality of a textile material has developed in recent years, wherein it has become common to try to change passive textiles into intelligent and interactive systems by integrating electronic components (i.e. devices that work by controlling the flow of electrons) into a textile. When the textile is an integral part of the electrical circuit comprising the electronic components, an electronic textile is obtained.

An example of an electronic textile is a photonic textile comprising a textile member with interwoven conductive yarns, and light emitting diodes (LEDs) attached to the textile member at designated positions. Typically, the LEDs are covered by a textile cover layer to provide a traditional textile feeling to the photonic textile, while a diffusive layer is arranged between the textile member and the textile cover layer.

The light emitted by the LEDs is first diffused by the diffusive layer, and then by the textile cover layer itself. When the textile cover layer has a reflective surface facing away from the LEDs, ambient light that is incident on the photonic textile from the outside is reflected, resulting in a reduced contrast of the photonic textile. The intensity of the light outputted from the photonic textile is reduced, as is the total efficiency of the photonic textile (down to 7 %).

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved electronic textile that alleviates the above-mentioned drawbacks of the prior art.

This object is achieved by an electronic textile according to the present invention as defined in the claims.

Thus, in accordance with an aspect of the present invention, there is provided an electronic textile comprising a textile member comprising a textile electrode, and an electronic component arranged in connection to the textile member. The electronic component is electrically addressable via the textile electrode. The electronic textile further comprises a top layer comprising a chromic compound. The top layer is arranged on top of the textile member. The top layer is arranged such that a sub area thereof, in response to an external stimulus capable of activating the chromic compound, is reversibly switchable from a first optical state to a second optical state.

Thus, there is provided an electronic textile having at least one individually addressable electronic component in connection with a textile member. On top of the textile member is provided a reversibly switchable top layer. The reversible switching is advantageously achieved by utilizing a chromic compound comprised in the top layer. The chromic compound may be activated with an external stimulus such that the optical state of the chromic compound is changed. A number of different external stimuli may be used, depending on the specific type of chromic compound utilized in the top layer. A sub area of the top layer which is subjected to the external stimulus capable of activating the chromic compound is switched from a first optical state to a second optical state. An area of the top layer that is not exposed to the external stimulus will remain in the first optical state. This allows for controlling the appearance of the electronic textile by stimulating electrically addressable electronic components, and further for creating combined functionalities of the components and the top layer. Since the switching is reversible the switched sub area will return to the first optical state when the sub area is no longer exposed to the external stimulus. The top layer advantageously allows for additional functionalities of the electronic textile.

In accordance with an embodiment of the electronic textile, the electronic component is one of a light source, and a resistor component. Thus addressable light sources or resistors are provided within the electronic textile which may be utilized to illuminate and/or heat an area of the electronic textile, provide decoration, display information or create some other visible effect. Furthermore, the light sources or resistor components may advantageously be utilized to produce light of one or more predetermined wavelengths, or a range of wavelengths, and/or heat, which may in turn be utilized to provide the external stimulus needed to activate the chromic compound in the switchable top layer.

Other advantages when utilizing components in the form of light sources in the present inventive concept include increasing the contrast of a light emitting textile array which can increase brightness and therefore increase power efficiency of the light emitting array. Also, the present inventive concept allows for achieving subtle color changes through a combination of emissive light and surface coloration changes.

In accordance with an embodiment of the electronic textile, the electronic component is a light source, which is one of a light emitting diode, an organic light emitting diode, an electroluminescent light source, and an optical fiber. Utilizing organic or inorganic light emitting diodes or luminescent light sources is advantageous, as these light source types are well known, relatively robust and are low cost. Optical fibers which provide light from a light source enables the use of single light source solutions, in which for example one light source is utilized to spread light via optical fibers that are extended within the electronic textile. In accordance with an embodiment of the electronic textile, the chromic compound is a thermochromic compound. Furthermore, the top layer is arranged such that the first optical state has a predetermined color, and the second optical state is transparent. Thus, a sub area of the switchable top layer which is subjected to heat switches from a predetermined color into a transparent state. The heat may be generated by the light sources. Furthermore, the electronic component may be chosen to be a resistor which generates heat when current is applied to it via the textile electrode. Alternatively, the heat may be generated by an external heat source. In the case of having light sources that, in addition to light, also generate heat capable of activating the thermochromic compound of the top layer, and if a certain light source in the electronic textile is turned on, the heat from the light source will switch the top layer sub area in its direct vicinity. The sub area becomes transparent to the generated light which is allowed to exit the electronic textile. As the surrounding areas of the top layer are kept in the first optical state, i.e. the predetermined color which preferably is chosen to be a dark color, the contrast of the light from the lit light source is increased, as compared to not having the switchable top layer applied on top of the textile member. Thus, the switchable top layer will act as a mask above the electronic textile having light sources applied to the textile member.

In accordance with an embodiment of the electronic textile, the chromic compound is a photochromic compound. Furthermore, the switchable top layer is arranged such that the first optical state has a first predetermined color, and the second optical state has a second predetermined color. The appearance of the electronic textile, with respect to the color displayed for an external viewer, is controlled by addressing specific light sources, thereby generating light which in turn activates the photochromic top layer. A sub area which receives the emitted light changes its color from the first predetermined color to the second predetermined color. The change of color may advantageously be utilized for a number of functions like providing decorations, displaying information, alerting a user, improving efficiency of emissive devices, etc.

In accordance with an embodiment of the electronic textile, resistors are woven or embroidered into the textile member. This is advantageous since the resistors may be utilized to create a number of stimuli for different types of chromic compounds in the reversibly switchable top layer, e.g. inducing magnetic fields, creating heat etc., as well providing functionalities to the electronic textile. In accordance with an embodiment of the electronic textile, the electronic textile further comprises a diffusive layer, which is arranged between the top layer and the textile member, which is advantageous for spreading light or heat in the electronic textile.

In accordance with an embodiment of the electronic textile, resistor contacts are arranged in the diffusive layer. Furthermore, the anode and cathode resistors are made of one of metal plates, wires, metal-coated fabric, metal-coated yarn, and conductive rubbers. In accordance with an embodiment of the electronic textile, the resistors are arranged in the diffusive layer by means of one of lamination, embroidering, weaving, soldering, ultrasonic welding and gluing. In accordance with an embodiment of the electronic textile, the chromic compound is a magnetochromic compound and the switchable top layer is arranged such that the first optical state has a first predetermined color, and the second optical state has a second predetermined color. The external stimulus is obtained by a magnetic field which is induced by applying current to the resistors. The resistors may be arranged to be individually addressable. A chosen area of the top layer may thus be addressed by applying current into the resistors of that area whereby a magnetic field is induced. The magnetochromic compound of the top layer in the addressed area will then be activated by the magnetic field. The color of top layer of the electronic textile is then changed from the first predetermined color to the second predetermined color. In accordance with an embodiment of the electronic textile, the chromic compound is an ionochromic compound, and the switchable top layer is arranged such that the first optical state has a first predetermined color, and the second optical state has a second predetermined color. The external stimulus is obtained by inducing ion transport in the top layer. In accordance with an embodiment of the electronic textile, the textile electrode is a conductive yarn woven, knitted, embroidered, braided or crocheted into the textile member. The use of conductive yarn allows for keeping the flexibility and feel of an ordinary textile, which in the end is a very important feature of an electronic textile when intended for use in for instance garments or household applications like curtains etc. When the textile electrode is provided in the weaving of the textile itself, the number of steps for producing the electronic textile is reduced.

In accordance with an embodiment of the electronic textile, the textile electrode is formed by applying a conductive ink onto the textile member. Applying conductive ink onto the textile member is advantageous since this provides a time- and cost- effective manufacturing of the textile electrode.

In accordance with an embodiment of the electronic textile, the top layer has at least two sub areas comprising different chromic compounds. Thus, several chromic effects may be utilized to create different effects in the electronic textile. This opens up for further functionalities of the electronic textile. As an example, one may divide the top layer into different sub areas, in which a magnetochromic compound and a photochromic compound are distributed in a predetermined order. Thus, one set of the sub areas will be activated to switch from a first optical state to a second optical state through activation by a magnetic field, while the other set of sub areas will switch from a first optical state to a second optical state through activation by light.

In accordance with an embodiment of the electronic textile, the chromic compound is a blend resulting from mixing at least two chromic compounds. When having a chromic compound blend, partial change is achievable in an area of the top layer that is subjected to an external stimulus capable of activating a chromic compound in the blend. Simultaneously applying different external stimuli may activate a plurality of chromic compounds in the blend. Hence, partial changes of the appearance of the electronic textile is achievable. Furthermore, gradient effects may be achieved due to the mixture composition of chromic compounds as well as the strength of the applied external stimulus. These and other aspects, features, and advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail and with reference to the appended drawings in which:

Fig. 1 is a cross-sectional view of an embodiment of an electronic textile according to the present invention.

Fig. 2a - b are cross-sectional views of an embodiment of an electronic textile according to the present invention. Fig. 3a - b are cross-sectional views of an embodiment of an electronic textile according to the present invention.

Fig. 4a - b are cross-sectional views of an embodiment of an electronic textile according to the present invention. Fig. 5a - b are cross-sectional views of embodiments of an electronic textile according to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS In the following embodiments the present invention will be described more fully and with reference to the accompanying drawings, in which exemplifying embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

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 crocheting, quilting, or felting. In particular, a textile may be woven or non- woven.

Fig. 1 illustrates a cross-sectional view of an embodiment of an electronic textile in accordance with the present invention. The electronic textile 10 comprises a textile member 11, typically a non-conductive textile member, provided with textile electrodes 30. In the context of this invention, a textile electrode is an electrical conductor comprised in a textile member, and as such it may serve as an electrode, a data bus, a thermo regulator, a heat distributor, a discharge protection element, or an optical type effect element. The textile electrodes 30 may be realized with conductive yarn which is placed into the textile member 11 through weaving, knitting, braiding, embroidering or crocheting. Other forms of textile electrodes may be arranged inside or onto the textile member 11 by means of printing a conductive ink onto the textile member 11, lamination of a conductive film which may be patterned, gluing and clamping of conductive materials etc.

Furthermore, the electronic textile 10 is arranged with at least one electronic component 12 which is electrically connected to the textile electrodes 30, such that each component 12 is addressable via the textile electrodes 30. The type of components 12 used in the electronic textile 10 may be chosen in accordance with each specific application, and may for example be light sources, diodes or resistors. Examples of suitable light sources are light emitting diodes, organic light emitting diodes, optical fibers and electroluminescent materials. Further, a top layer 20 is arranged on top of the textile member 11. The top layer 20 comprises a chromic compound. In this example the top layer 20 is a textile layer that has been impregnated with a dye comprising a chromic compound. The top layer 20 may be arranged by means of spray coating, evaporation, dip coating, spin coating and painting. In an embodiment of the electronic textile, the light source 12 itself may comprise a light spreading optical component, e.g. a lens, a diffuser, a transmission mirror, etc. Furthermore, in an alternative embodiment the light source may be provided with a light directing element, a light focusing element etc.

An embodiment of the electronic textile 40, as illustrated in Figs. 2a-b, comprises a non-conductive textile member 11 into which textile electrodes 30 have been woven during manufacturing. Components 12 in the form of light sources, which in this embodiment are light emitting diodes (LEDs), are arranged such that they are addressable via the textile electrodes 30. The components 12 are activated by connecting them to a power source, which is preferably controlled with some control element. The power source, which may be a battery, and the control element are not shown in the figures.

The electronic textile 40 comprises a top layer 20, and a diffusive layer 15 arranged between the textile member 20 and the top layer 20. The diffusive layer 15 spreads the light emitted from the LEDs 12. Alternatively, the LEDs 12 (or some other utilized light sources) may be arranged with an individual optical component for spreading the light (not shown in the figures).

Now, let' s look at two examples of the embodiment. Firstly, a thin thermochromic textile is arranged as the top layer 20. The top layer 20 may be chosen to be 50 micrometers or thicker. In a first optical state of the top layer 20, the thermochromic textile has a first color, as illustrated Fig 2a. However, as one of the light sources 12, is activated, the area in its direct vicinity will be heated. The heat provided by the light source will change the thermochromic compound, i.e. the dye, into a transparent state which represents a second optical state. Thus, sub areas 21 of the top layer 20 which are subjected to the external stimulus, here being heat produced by the light sources, switch from a colored state to a transparent state. The sub areas 22 of the top layer that are not subjected to the external stimulus remains unswitched, and thus colored. If the color of the first optical state is selected to be dark, the contrast of the light sources will be improved as compared to having light sources without the top layer. When the light sources are deactivated, the switched sub areas 21 will return to the first optical state.

Well-known thermochromic compounds are Leuco dyes and liquid crystals. They may be applied as paint or ink to the top layer 20. An advantage with liquid crystals is that they can display many colors as a function of temperature. Furthermore, they are accurate in their color switching with respect to the temperature. Thus, by utilizing a liquid crystal material which shows several different colors within a number of temperatures ranges (each temperature range corresponding a specific color), the top layer 20 may actually be switched between a number of colors by subjecting it to different temperatures. Leuco dyes exist in various colors and switch from colored to transparent in a

3°C temperature range.

Secondly, a photochromic textile is arranged as the top layer 20. The photochromic textile is arranged to in a first optical state have a first predetermined color. As the light sources 12 are activated the emitted light will activate the photochromic compound in the top layer, and subjected sub areas 21 are thus switched into a second optical state. The second optical state is here a second predetermined color. Sub areas 21 of the top layer 20 that are not subjected to light will remain in the first optical state. Thus the color appearance of the electronic textile is controlled by addressing the light sources 12. The distribution of the light sources (or components in general) are typically governed by the specific application. When utilizing the electronic textile as a display, the light sources (or components in general) and the textile electrodes 30 are preferably arranged in the form of an addressable matrix, as illustrated in the top- view of the textile member 11 in Fig. 3a.

In an embodiment of the electronic textile, the components 12 are resistor components arranged in a matrix formed by the textile electrodes 30, as schematically illustrated in Fig. 3a. The conductive matrix allows for individually addressing each component 12, and may be arranged by providing separate anode- and cathode layers arranged on top of each other, which layers are separated by an insulative material (not shown) to provide an anode pattern and a cathode pattern to which the components 12 are connected, or by arranging the anode- and cathode pattern in the same layer but with separated track routes. The individual addressing of the components 12 provides a display functionality such that information in the form of figures, text, or ornamentations may be displayed.

Further, a thermochromic layer is arranged as the top layer 20. By generating heat at designated positions for the components 12 in the addressable matrix formed by the textile electrodes 30, images may be displayed on the electronic textile 10. In an alternative embodiment, the top layer is provided with a magnetochromic compound. The magnetic field which is induced when current is applied to the resistors 12 may then be utilized to activate the magnetochromic compound and thus switch sub areas subjected to the external stimulus to change the coloration of the dye. In the foregoing exemplifying embodiment, components 12 in the form of resistors components were arranged in connection to textile electrodes 30, which were arranged in the textile member 11.

In other embodiments in accordance with the present invention, resistor contacts are woven or embroidered into the textile member 11. The resistor contacts can be resistive conductive yarn or ink tracks. In addition, the yarn and tracks can alternatively be placed in the top layer 20, or the diffusive layer 15, which is described more in detail later and in connection to Figs. 4 and 5.

In an embodiment of the electronic textile according to the present invention, as illustrated in Fig. 3b, the light sources 12 are realized with optical fibers, which transports light from a light source (not shown) to a designated position in the electronic textile. The fibers 12 may be arranged with light spreading materials or structures contained within the fibers at predetermined positions x, y. The light source may then advantageously be a single light source positioned distanced from the predetermined positions. The light output may alternatively be achieved with optical components (not shown).

In an embodiment of the electronic textile 70 according to the present invention, as illustrated in Fig. 4a, the top layer 20 comprises an ionochromic compound. Here, conductive leads 72 are arranged on top of the textile member 11, and are further arranged such that they enclose part of the top layer material between them. The materials of the conductive leads 72 are chosen to be suitable to serve as anodes and cathodes for ion transfer through the top layer 20. Preferably the materials are capable of providing ions that will influence the ionochromic dye material in the top layer 20. The external stimulus to cause a sub area of the top layer 20 to switch between the first optical state and the second optical optical state is thus obtained by ion transport, which is induced by applying current to the conductive leads 72. It should be noted that there are alternative ways of arranging the conductive leads 72 such that they at least partly enclose ionochromic material of the top layer 20, e.g. conductive leads may be arranged directly under and on top of the top layer.

In an embodiment of the electronic textile 50, as illustrated in Fig. 4b, the electronic textile comprises a diffusive layer 15 in which the resistor contacts 52 are arranged. The resistors contacts 52 are stripes of metal plates which are laminated into the diffusive layer. Alternatively, the resistor contacts 52 may be arranged as wires, metal-coated fabric, metal-coated yarn, conductive rubbers, and conductive ink. The method for arranging them inside the layer may be one of lamination, embroidering, weaving, soldering, gluing, knitting, crocheting, printing, or painting. The electronic textile 50 is further provided with a top layer 20. The top layer 20 comprises a chromic compound which is magnetochromic or thermochromic. The switchable top layer 20 is furthermore arranged such that the first optical state has a first predetermined color, and the second optical state has a second predetermined color. When a current is applied to the resistor contacts 52, heat and a magnetic field is generated. Depending on the chromic compound utilized in the top layer 20, the heat and/or magnetic field may be utilized to switch the top layer 20.

In the present inventive concept, the top layer is impregnated with a thermochromic, photochromic, magnetochromic or ionochromic material. However, the impregnation is not limited to a single type of chromic material. There is a possibility to make use of a chromic compound that is a blend resulting from mixing at least two chromic compounds.

In accordance with an exemplifying embodiment of the electronic textile, as illustrated in Fig. 5a, there is provided an electronic textile 60 which comprises a textile member 11, resistors 54 arranged in a diffusive layer 15, which is arranged between the textile member 11 and a top layer 20. Furthermore, textile electrodes 30 are arranged on the textile member 11 to provide power to the light sources 12, which are arranged in connection to the textile member 11. Now, consider the top layer 20. The top layer 20 is arranged having different sub areas 61, 62 and 63. Sub areas 61 comprise a blend of a magnetochromic and a thermochromic compound, sub area 62 comprises a photochromic compound, and sub area 63 comprises a thermochromic compound. Now firstly, the thermochromic compound in sub area 61 and the thermochromic compound in sub area 63 are chosen such that they are activated at two different temperatures. Switching of sub areas 61 may thus be activated by a magnetic field induced by applying current to the resistors 54, or heat generated by applying a current to the resistors 54, or heat or a magnetic field from the surroundings. Sub area 62 may respond to light from an activated light source 12 within the electronic textile, or to ambient light from the surrounding, for example from an external light source 62. Switching of sub area 63 may be activated by heat generated in the electronic textile or to the temperature of the surroundings, and the activation may be triggered at another temperature than the activation of switching in sub area 61. Thus, the number of achievable optical effects of the appearance of the electronic textile 60 is high. In alternative embodiments, the sub areas may contain only non-blended chromic compounds, only blended chromic compounds etc.

An alternative embodiment to the embodiment above is illustrated in Fig. 5b, in which the resistor contacts 54 are arranged in the top layer. The electronic textile in accordance with the present inventive concept is applicable in garments, dynamic interior lighting systems at home or on the move (e.g. furniture upholsteries, curtains, carpets), wearable communication displays (e.g. in backs, jackets), photonic therapy devices (baby jaundice sleeping back, acne treating t-shirt, wound healing plaster, etc.).

Above, embodiments of the electronic textile according to the present invention as defined in the appended claims have been described. These should be seen as merely non-limiting examples. As understood by a skilled person, many modifications and alternative embodiments are possible within the scope of the invention. It is to be noted, that for the purposes of this application, and in particular with regard to the appended claims, the word "comprising" does not exclude other elements or steps, that the word "a" or "an", does not exclude a plurality, which per se will be apparent to a person skilled in the art.