GB2563250A

GB2563250A - Flexible illuminatable laminate

Info

Publication number: GB2563250A
Application number: GB1709082.0A
Authority: GB
Inventors: Miller Nicholas
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2017-06-07
Filing date: 2017-06-07
Publication date: 2018-12-12
Anticipated expiration: 2037-06-07
Also published as: GB2563250B; GB201709082D0

Abstract

A flexible fabric is produced by forming a layer of optical fibres such that the fibres form loops in an edge region of the fabric. The loops 3 in the edge region are cut to form cut-fibre ends. The ends are connected to a light source. Loops of the fibres may be formed into a matt and the loops in the edge regions gathered together into a bundle and cut and the bundle connected to a single light source. The mat may be incorporated into a laminate by locating it between upper 13 and lower 15, preferably elastic, sheets, one of which is translucent. The mat may be formed by knitting or macramé. A sheath of the fibre may be damage such as mechanically, with a laser or with a chemical such that light is emitted from the fibre surface. The fabric may be used to cover interior surfaces of a car having a compound curvature, such as a head-lining, boot-lining or door casing.

Description

Flexible Illuminatable Laminate

Introduction

The present invention relates to a flexible illuminatable fabric or laminate suitable for covering the interior surfaces of a car, more widely to a flexible illuminatable fabric or laminate suitable for covering surfaces with compound curves more generally, and to methods of producing the flexible illuminatable fabric or laminate.

Background to the Invention

Use of illuminated fabrics to light up interior spaces and provide aesthetically appealing decoration has become extremely popular in recent years. Examples of use of illuminated fabrics include as drapery in homes or business premises and as an alternative to conventional lights in domestic and commercial buildings.

Fabrics or other textile products containing illuminated fibres as well as methods for producing optical-fibre based fabrics are known in the art. US 4,234,907 describes a light emitting fabric comprising a woven plurality of optical fibres wherein each of the fibres is deformed e.g. via notches at discrete intervals along its length to allow light to radiate therefrom. The distance between successive notches along the length of each optical fibre progressively decreases in proportion to the distance between the source of illumination and the notches so as to provide for uniform emission of light along the length of each fibre. The optical fibres in said fabric can comprise the warp fibres and/or the weft fibres i.e. the woven fabric generally still contains a proportion of conventional fibres made from e.g. cotton, nylon, wool. WO 02/12785 describes a woven fabric made of texture threads and warp threads, wherein at least a number of non-adjacent warp or texture threads consist of light guiding fibres. Thus, like in US 4,234,907, a proportion of the fabric is still made of conventional fibres. US 7,137,416 describes a method for weaving flat, stiff fabric comprising optical fibres as warp and/or weft threads, characterised in that it comprises the weaving of a Jacquard motif forming a matrix that separates and identifies, relative to the adjacent threads, the input ends of a predetermined number of optical fibres intended to be grouped together in bundles and connected to a common light source.

However, all of the optical-fibre based illuminated fabrics described hitherto are highly rigid and lack both flexibility and elasticity. Movement of the fabric in the direction of the optical fibres is highly restricted and thus it follows that the fabrics described are unsuitable for use as a covering for surfaces containing compound curves, a feature common to e.g. the interior portions of a car.

For covering surfaces containing compound curves, it is desirable to have a fabric which is flexible, stretchy and possesses elasticity so that the fabric can conform to any shape or any shaped body without creasing or bunching, and for covering moving surfaces a fabric is desired that can be repeatedly folded and unfolded without damaging or creasing the fabric.

Accordingly, it is an aim of the present invention to provide an alternative illuminatable fabric. A further aim is to provide an improved illuminatable fabric that is flexible and possesses elasticity and is thus suitable for covering surfaces with compound curves and/or suitable to be folded and unfolded. A still further aim is to provide a method for producing a fabric with one or more of all of the aforementioned characteristics.

Summary of the Invention

Accordingly, the invention provides a method of making an illuminatable fabric having one or a plurality of layers, comprising forming a flexible optical fibre into a layer having at least an edge and comprising a plurality of optical fibre loops exposed along the edge; cutting one or more exposed loops along the edge to form a plurality of cut fibre ends; and connecting the cut fibre ends to a light source so they can be illuminated.

The invention also provides a method of producing a flexible illuminatable laminate, comprising the steps of: (i) constructing a flexible optical fibre mat with loops at the periphery; (ii) gathering and cutting the ends of the loops at the periphery of the optical fibre mat to form at least one bundle of cut ends of optical fibres; (iii) connecting the bundle of cut ends of optical fibres to at least one light source; and (iv) optionally, mounting the optical fibre mat in between an upper and a lower sheet of elastic material, wherein at least one sheet is translucent.

An illuminatable fabric is provided also by the invention, having one or a plurality of layers, comprising a layer formed of a flexible optical fibre having at least an edge and comprising a plurality of cut optical fibre ends along the edge, formed by cutting exposed fibre loops along the edge, wherein the cut fibre ends can be connected to a light source so they can be illuminated.

The invention further provides a flexible illuminatable laminate comprising; a) a lower sheet of translucent, optionally elastic material; b) a flexible optical fibre mat connected to at least one light source; and c) an upper sheet of optionally elastic material.

The fabrics / laminates of the invention are advantageously flexible and are suitably used to cover an interior surface of a car, and preferably made as per a method of the invention. The fabrics I laminates preferably also include one or more light sources.

Details of the Invention A method of the invention comprises forming a flexible optical fibre into a layer having at least an edge and comprising a plurality of optical fibre loops exposed along the edge; cutting one or more exposed loops along the edge to form a plurality of cut fibre ends; and connecting the cut fibre ends to a light source so they can be illuminated.

The layer may be a flexible optical fibre mat, being composed of one or more optical fibres, and may be incorporated within a multi-layered laminate material, typically with layers above and below.

Accordingly, a further method of the invention comprises: (i) constructing a flexible optical fibre mat with extending loops at the periphery; (ii) gathering and cutting the ends of the loops at the periphery of the optical fibre mat to form at least one bundle of optical fibres; (iii) connecting the bundle of optical fibres to at least one light source; and (iv) optionally, mounting the optical fibre mat in between an upper and a lower sheet of optionally elastic material, wherein at least one sheet is translucent.

The cut ends are thus gathered together, optionally in a single bundle and optionally in a plurality of bundles along the edge I periphery of the mat.

Preferably the layer / mat comprises a plurality of loops, more preferably stiches, and is made from a small number of optical fibres, and can be made from a single optical fibre. The loops may be laid over each other. Preferably the loops are knitted or macramed so as to interlock or interconnect to form an integral fabric layer.

Thus, the flexible optical fibre layer / mat may be constructed by various means including by knitting and macrame. An advantage of the invention is the effective elasticity of the optical fibre mat and thus stitch patterns providing flexibility and elasticity are particularly suitable. In the context of the invention elasticity in the fabric is perceived in use as a property of the fabric as a whole due to its multiple, loose loops despite being made from fibres that are flexible but individually are substantially inelastic along their length. With regards to knitting, suitable stitches include garter stitch and ribbing. In relation to macrame, suitable patterns include those comprising a series of loops.

Generally, optical fibres are made of either glass or plastic. Glass fibres tend to be more rigid and brittle whereas plastic fibres are more flexible. The optical fibres used in illuminatable fabrics generally and indeed in the flexible illuminatable fabric / laminate of the present invention have considerable mechanical flexibility and are able to withstand the bending that is necessary during knitting and macrame without breaking. Accordingly, it is preferred to use optical fibres made of or comprising plastic. Suitable plastic optical fibres include those made of polycarbonate (PC), polystyrene (PS), cyclic olefin copolymer (COC), amorphous fluoropolymer (CYTOP), poly(ethyl methacrylate) (ΡΕΜΑ), poly(butyl acrylate) (PBA). Particularly suitable are those made of poly(methyl methacrylate) (PMMA).

Typically, optical fibres have an internal core surrounded by a cladding layer or external sheath. The external sheath may have a lower refractive index than the internal core, which causes internal reflection of light so that light travels through the internal core of the fibre, entering at one end of the fibre and exiting at the other. Consequently, fabric made with a plurality of optical fibres only illuminates at the ends of the optical fibres, unless treated as now described. In order to allow light to be emitted along the length of the optical fibre, it is an option to remove or damage at least a portion of the external sheath either mechanically or chemically or deform the fibre per se by bending the fibre at discrete locations along the fibre length. Suitable ways of deforming the surface mechanically include scratching and laser treatment (as described in WO 2004/057079A1). Suitable means of deforming the surface chemically are described in WO 02/12785. The damage may be inflicted upon a specific portion of the optical fibre if it is desired for light to be emitted intermittently along the length of the fibre i.e. at individual locations. Alternatively, the entirety of the optical fibre external sheath may be damaged if it is desired that light is emitted along the length of the fibre.

During construction of the flexible optical fibre layer / mat loops are exposed and accessible at the periphery of the mat, preferably along at least one side or edge, more preferably along at least two sides. One or more loops are cut as a means of connecting the flexible optica! fibre mat to a light source and therefore the size or height of the exposed loops should be sufficient so as to allow the loops to be gathered and cut; cut ends can be individually connected to light sources or grouped so as to form at least one bundle of optical fibres that can be connected to, and are suitably arranged to receive light from, a light source. Generally, the exposed loops are cut along substantially the whole of a side or edge, then collected into one or more bundles. Preferably, the exposed loops should be no less than 10cm long measured from the periphery of the mat.

The light source can be any conventional light producing means capable of directing light into the cross-sectional area of a bundle of optical fibres. The light source can be white and/or coloured without limitation. The light source may produce a single colour, or in other cases, e.g. where a RGB LED is used, multiple colours. Alternatively, multiple light sources of different colours can be used in combination, such as a plurality of differently coloured LEDs. In the flexible illuminatable laminate, at least one of the upper or Sower sheets of elastic material may separately be tinted according to the final light effect desired.

The power output of the light source(s) required will depend on multiple parameters including the dimensions of the flexible optical fibre mat i.e. larger mats will require more light and the number of optical fibres within the bundle i.e. the more optical fibres within the bundle, the more light will be required. The power output of the light source(s) may also depend on the amount of damage to the optical fibre(s) i.e. mats where the optical fibre(s) are more severely damaged may require more light. For aesthetic reasons, in a final product incorporating the layer / laminate of the invention the light source and the electrical connections, e.g. wires or circuit board elements are preferably not visible in use.

The flexible optical fibre layer / mat can be used alone or alternatively it can be mounted between an upper and/or a lower sheet of material to form a laminate. To achieve maximum flexibility and / or elasticity it is preferred that at least one of the sheets is made of an elastic material, more preferably both sheets are made of an elastic material. To ensure that light can radiate from the laminate, at least one of the sheets needs to be translucent. In certain embodiments of the invention, the translucent sheet acts as a diffuser and is thus diffusing. The diffuser may act to allow the light emitted from the optical fibres to be scattered, optionally creating a more homogenous, softer light, that is distributed more evenly. Suitable translucent fabrics for use in the invention include silk organza, voile, fine cotton lawn, chiffon. More preferably, the upper or lower sheet, still more preferably both the upper and lower sheet, are made from an elastic material. An example of a suitable material for use in the invention is lycra. Mounting the flexible optical fibre layer I mat between two sheets of elastic material maximises the flexibility and elasticity of the fabric I laminate.

The flexible illuminatable laminate of the invention is particularly suitable for use in covering surfaces containing compound curves, a feature common to e.g. the interior portions of a car. Examples of interior surfaces of cars that may be covered using the flexible illuminate fabric / laminate of the invention include the headliner, the boot lining and the door casing. Advantageously, the flexible nature of the laminate ensures that no bunching is observed when the aforementioned contoured surfaces are covered. This property also means that the flexible illuminatable laminate is particularly suitable for use as a covering for a headliner of a convertible car possessing a retractable roof. In a convertible car, the roof and thus the headliner may be folded for prolonged periods of time, typically several weeks or months; the elastic nature of the laminate ensures that no creasing is observed when the headliner is unfolded and thus the roof is in the closed position. The flexible optical fibre layer / mat may also be suitably used to cover surfaces with compound curves in the same manner as the flexible optical fibre laminate albeit the visibility of the optical fibres will inevitably alter the aesthetics of the covering. A further advantage of the invention is that the dimensions of the flexible optical fibre layer / mat are limited only by the intended application of the layer /mat or fabric / laminate. Flexible optical fibre layer(s) / mat(s) constructed for use as a covering for a headliner In the interior of a car will necessarily be longer and wider than those constructed for use as a covering for the interior surface of a glove box. Particular applications may also require that the flexible optical fibre layer / mat or fabric / laminate has a specific depth or thickness. Cars comprising a sunroof have a limited space in the roof for the headliner and thus flexible optical fibre layer(s) / mat(s) or fabric(s)/laminate(s) intended for use as a covering for a headliner comprising a sunroof preferably have a depth / thickness of 10mm or less, more preferably 7.5mm or less.

The principle feature governing the depth of the optical fibre layer / mat and thereby the fabric or laminate is the diameter or ‘thickness’ of the optical fibre. Generally, optical fibres for use in the invention should be sufficiently narrow so as to allow the optical fibre to be bent and manipulated into loops. Preferably, optical fibres for use in the invention have a diameter less than 1.5mm; more preferably the diameter is less than 1mm.

If the flexible optical fibre layer I mat is used alone then the depth of the layer I mat determines the overall depth of the fabric whereas if the flexible optical fibre layer / mat is mounted between an upper and lower sheet of material, optionally elastic, then the depth of the laminate is determined by the combined depth of all three layers.

In a specific embodiment of the invention, a car headliner of approximately 1.5m x 1,5m is prepared by knitting a 0.7mm diameter optical fibre into a fabric of 1.5m x 1,6m x 0.006m with a stitch density of approx. 1-2 and slightly elongated loops of fibre along the right- hand edge. These were cut at the extremities of the loops and gathered into bundles each of 10 cut ends (5 loops) and connected to white light LEDs, giving a final width of 1.5m of visible fabric. The optical fibre was pre-treated to provide it with random discontinuities in the fibre sheath along its length, giving a speckled lighting effect when in the final headliner product in situ.

Examples

The invention is now illustrated in the following examples with reference to the accompanying drawings in which:

Fig. 1 is a photograph of a flexible optical fibre layer / mat of the invention; and Fig. 2 is a photograph of a flexible illuminatable laminate of the invention.

Referring to fig. 1, a flexible optical fibre layer / mat 1 is shown which was constructed by knitting, being approx. 10cm in height and 5mm thick, and having approx. 1-1½ wales and course per cm. The layer shown has been manipulated over contoured surfaces and has lost some of the eveness of the original knitted loops. A single PMMA optical fibre of diameter 0.25mm was knitted to form a fabric of interlocked optical fibre loops 3. The entire right-hand edge of the layer / mat consisted of exposed, elongated loops 5 (elongated compared to other knitted stitches in the fabric) which are not shown as they were previously exposed and then have been gathered into a single bundle 7 and cut so as to form a plurality of cut fibre ends that are ready to receive light from a light source (not shown) and be incorporated into a product.

Referring to fig. 2, a flexible illuminatable laminate 9 is shown which comprises a flexible optical fibre layer / mat 11, constructed by knitting as described in fig. 1, mounted between an upper sheet of elastic material 13 and a lower sheet of elastic material 15. Upper and lower sheets are rolled back in the right-hand portion of the laminate to show the middle mat of knitted optical fibre. Along the far, right-hand edge, loops of fibre have been cut and collected into bundles for connection to an LED light source in manufacture of a car headliner.

Accordingly, the invention provides methods of making illuminatable laminates, especially for car interiors.

Claims

1. A method of making an illuminatable fabric having one or a plurality of layers, comprising: forming a flexible light fibre into a layer having at least an edge and comprising a plurality of light fibre loops exposed along the edge; cutting one or more exposed loops along the edge to form a plurality of cut fibre ends; and connecting the cut fibre ends to a light source so they can be illuminated.

2. A method according to claim 1, comprising forming loops of the fibre into a mat.

3. A method of producing a flexible illuminatable laminate according to claim 2, comprising: constructing a flexible optical fibre mat with loops at the periphery; gathering and cutting the ends of the loops to form at least one bundle of optical fibres; connecting the bundle of optical fibres to at least one light source; and mounting the optical fibre mat in between an upper and a lower sheet of optionally elastic material, wherein at least one sheet is translucent.

4. A method according to any preceding claim, wherein the layer or mat comprises interlocked loops.

5. A method according to any preceding claim, comprising knitting the optical fibre.

6. A method according to any preceding claim, comprising forming the mat or layer by macrame.

7. A method according to any preceding claim, wherein the optical fibres are made from plastic.

8. A method according to claim 7, wherein the optical fibres are made from poly(methyl methacrylate) (PMMA),

9. A method according to any preceding claim, wherein the optical fibres have a diameter of less than 1 mm.

10. A method according to any preceding claim, wherein the light source is capable of generating at least two different colours.

11. A method according to claim 10, wherein the light source is an RGB LED.

12. A method according to any previous claim, comprising the preliminary step of damaging the external sheath of the optical fibre such that light is emitted from the surface of the fibre.

13. A method according to claim 12, wherein the damage is mechanical damage.

14. A method according to claim 13, wherein the damage is via scratching or laser treatment.

15. A method according to any of claims 12-13, wherein the damage is chemical damage.

16. A method according to any previous claim, for making a laminate comprising at least the layer or mat and a translucent layer, wherein the translucent layer is made from material that is elastic and diffusing.

17. A method according to any previous claim, wherein the flexible fabric or laminate has a thickness of 7.5mm or less.

18. An illuminatable fabric comprising one or a plurality of layers, comprising a layer formed of loops of a flexible light fibre, the layer having at least an edge, and comprising a plurality of cut light fibre ends along the edge, formed e.g. by cutting exposed fibre loops along the edge, wherein the cut fibre ends can be connected to a light source so they can be illuminated.

19. A fabric according to claim 18, comprising a mat of loops of optical fibre.

20. A flexible illuminatable laminate comprising; a) a lower sheet of translucent optionally elastic material; b) a flexible optical fibre mat according to claim 18 or 19, connected to at least one light source; and c) an upper sheet of optionally elastic material.

21. A flexible illuminatable laminate according to claim 20, comprising knitted loops of optical fibre.

22. A flexible illuminatable laminate according to claim 20, comprising a flexible optical fibre mat of loops of optical fibre made by macrame.

23. A fabric or flexible illuminatable laminate according to any of claims 18 to 22, wherein the optical fibres are made from plastic.

24. A fabric or flexible illuminatable laminate according to claim 23, wherein the optical fibres are made from poly(metbyl methacrylate) (PMMA).

25. A fabric or flexible illuminatable laminate according to any of claims 18 to 24, wherein the optical fibres have a diameter of less than 1mm.

26. A fabric or flexible illuminatable laminate according to any of claims 18 to 25, wherein the light source is capable of generating at least two different colours.

27. A fabric or flexible illuminatable laminate according to claim 26, wherein the light source is an RGB LED.

28. A flexible illuminatable laminate according to any of claims 20 to 27, wherein the sheet of translucent elastic material functions as a diffuser.

29. A flexible illuminatable laminate according to any of claims 20 to 28, wherein the flexible illuminatable laminate has a thickness 7.5mm or less.

30. Use of the flexible illuminatable laminate of any of claims 20 to 29 to cover an interior surface of a car.

31. Use of the flexible illuminatable laminate according to claim 30, wherein the interior surface comprises compound curves.

32. Use of the flexible illuminatable laminate in accordance with any of claims 30 to 31, wherein the interior surface is the headliner of a car.

33. Use of the flexible illuminatable laminate in accordance with claim 32, wherein the headliner comprises a sunroof.

34. Use of the flexible illuminatable laminate in accordance with any of claims 30 to 31, wherein the interior surface is the boot lining.

35. Use of the flexible illuminatable laminate in accordance with any of claims 30 to 31, wherein the interior surface is a door casing.

36. A car comprising a headliner made of or comprising a fabric or flexible illuminatable laminate according to any of claims 20 to 29.