Patent Publication Number: US-10767850-B2

Title: Attaching light emitting devices to items of clothing

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from United Kingdom Patent Application number 1811272.2, filed on Jul. 10, 2018 the whole contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method of attaching a light-emitting device to an item of clothing. 
     The present invention also relates to an apparatus defining an item of clothing having a strip of a reflective tape surrounded by fluorescent material. 
     It is known to provide garments with light emitting diodes that may provide permanent illumination or that may be activated in response to detecting a particular condition. For example, as described in U.S. Pat. No. 9,992,516, assigned to the present application, red light-emitting diodes are illuminated in response to a local detection of a toxic substance and blue light-emitting diodes are activated if a substance is detected by a co-worker. In these known systems, the light-emitting diodes are supported by a rubber cover that is externally stitched to an item of clothing. Although such an approach does provide a degree of protection for the light-emitting diodes, the devices themselves are exposed and may be damaged, possibly due to the presence of dust. Furthermore, it is possible for the rubber covers to bend resulting in greater exposure of the light-emitting diodes, that may in turn result in them becoming damaged or chipped. 
     Increasingly, higher levels of sophistication are being provided by items of clothing of this type, including internal communication between detection devices and data transmission and storage etc. As the overall value of the items of clothing increase, there is a greater requirement for providing overall reliability; it would be undesirable for an item of clothing to be rejected due to a relatively inexpensive failure. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, there is provided a method of attaching a light-emitting device to an item of clothing, comprising the steps of: supporting a light-emitting device on a substrate; connecting power cables to said substrate; applying an adhesive film to an inside surface of a clothing fabric; creating a hole through said adhesive film and said clothing fabric at an intended position for said light-emitting device; positioning a central portion of a clear plastics material over said hole to define a window, such that said central portion is secured by said adhesive film, a first flap extends from a first side of said central portion and a second flap extends from a second side of said central portion; locating said light-emitting device at the position of said window; folding said first flap over said substrate; further-folding said second flap over said folded first flap; and attaching said further folded second flap to said folded first flap to define a sealed enclosure for said substrate. 
     In an embodiment, plural light-emitting devices are supported by the substrate and the method may include a step of connecting a data cable to the substrate. 
     The clear plastics material may be made from any suitable compound providing this functionality but, in an embodiment, the clear plastics material is clear poly vinyl chloride. 
     In an embodiment, the adhesive film comprises: a central barrier film; a first adhesive layer on an outer surface; and a second adhesive layer on an inner surface. The applying step may include the steps of: removing a first backing material from the first adhesive layer; locating the first adhesive layer upon the inside surface of the clothing fabric; and applying heat and pressure to a second backing material attached to the second adhesive layer. 
     According to a second aspect of the present invention, there is provided an apparatus defining an item of clothing having a strip of a reflective tape surrounded by florescent material, comprising: embedded light-emitting devices connected to a loom of power and data cables and supported on a substrate; respective windows for each said light-emitting device, in which a hole cut through said reflective tape is covered, by a clear plastics material, having a first flap and a second flap, wherein: said first flap is folded around said substrate; said substrate is secured by said second flap being further folded around said first flap; and said clear plastics material is secured to a clothing fabric by an adhesive film through which said holes have also been cut. 
     Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. The detailed embodiments show the best mode known to the inventor and provide support for the invention as claimed. However, they are only exemplary and should not be used to interpret or limit the scope of the claims. Their purpose is to provide a teaching to those skilled in the art. Components and processes distinguished by ordinal phrases such as “first” and “second” do not necessarily define an order or ranking of any sort. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  shows a flexible printed circuit board with light-emitting devices; 
         FIG. 2  shows the connection of ribbon cables; 
         FIG. 3  shows the application of a heat shrink over the ribbon cables identified in  FIG. 2 ; 
         FIG. 4  shows a loom assembled from strips of the type identified in  FIG. 3 : 
         FIG. 5  shows the front of an item of clothing; 
         FIG. 6  shows the rear of the item of clothing identified in  FIG. 5 ; 
         FIG. 7  illustrates a composite adhesive film; 
         FIG. 8  illustrates the application of the adhesive film, identified in  FIG. 7 , to an inside surface of a clothing fabric; 
         FIG. 9  illustrates the application of a template to assist with the drilling of holes; 
         FIG. 10  shows the deployment of a power drill to perform a twist cutting operation; 
         FIG. 11  shows the removal of a protective film; 
         FIG. 12  shows the application of a clear plastics material over the holes; 
         FIG. 13  shows the application of a gasket; 
         FIG. 14  shows the application of an LED strip over the gasket identified in  FIG. 13 ; 
         FIG. 15  shows the application of a protective layer and the folding of flaps: and 
         FIG. 16  shows a cross-section of the fully assembled apparatus. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     FIG.  1   
     In an embodiment, a flexible printed circuit board  101  provides a substrate for supporting a first light-emitting device  111 . In this embodiment, a second light-emitting device  112  and a third light-emitting device  113  are also supported by the flexible printed circuit board  101 . 
     A first set of contacts  121  is provided for connecting to an input side of a loom. Furthermore, a second set of contacts  122  is provided for connecting to an output side of the loom. The contacts are pre-tinned to assist with loom soldering. 
     FIG.  2   
     A loom is assembled using ribbon cables to connect flexible printed circuit boards of the type described with reference to  FIG. 1 . A first ribbon cable portion  201  has conductors that are soldered to the first set of contacts  121 . Similarly, a second ribbon cable portion  202  has conductors that are soldered to the second set of contacts  122 . 
     FIG.  3   
     As illustrated in  FIG. 3 , a first adhesive lined heat-shrink  301  is applied over the soldered connections of the first ribbon cable portion  201 . Similarly, a second adhesive lined heat shrink  302  is applied over the soldered connections of the second ribbon cable portion  202 . 
     The grouping of three LED devices on the substrate of a flexible printed circuit board, as illustrated in  FIG. 3 , may be identified as a device strip  303 . To construct a loom, plural device strips are connected by cables and, in an embodiment, four device strips are connected in this way to construct a loom. In this embodiment, each device strip includes three light-emitting devices, although it should be appreciated that other configurations of devices are possible. 
     In some looms, devices may emit light of a single color in response to being energized by a control unit. However, in alternative embodiments, devices of different colors may be included in each strip. Furthermore, in an alternative embodiment, individual devices may be capable of producing multiple colors and color selection may be achieved in response to receiving control data by means of a data cable. Thus, the cables present within the loom generally include power cables and data cables. Furthermore, in addition to conveying data to the individual devices, the data cables may also be configured to receive data from detecting devices connected to the loom. 
     After the application of the adhesive lined heat shrinks  301 / 302 , a clear silicone conformal coating may be applied, suitable for operating over a temperature range of between minus sixty-five degrees Celsius and two-hundred degrees Celsius. In an embodiment, the silicone coating has a thickness of two hundred micrometres, thereby preventing excessive bending of the flexible printed circuit board, to ensure that shouldered devices remain in place. 
     FIG.  4   
     The device strip  303  is shown in  FIG. 4 , connected in a loom that includes a second device strip  402 , a third device strip  403  and a fourth device strip  404 . In an embodiment, the second device strip  402  may include enhanced functionality, possibly including detectors for detecting ambient light conditions. 
     In the embodiment of  FIG. 4 , the complete loom  401  includes an interface circuit  405  which, in an embodiment, may include memory devices for storing control instructions and/or operational data etc. In addition, a loom connector  406  is provided for connecting the loom to a control circuit. 
     FIG.  5   
     An device loom of the type described with reference to  FIG. 4  is located within an item of clothing, such as that illustrated in  FIG. 5 . In this example, the item of clothing is a vest but the invention may be deployed in other types of clothing, such as harnesses and jackets etc. 
     In this example, the item of clothing is constructed from a fluorescent material  501 . In addition, reflective tape  502  has been located over the fluorescent material, thereby increasing the visibility of the vest during both daylight conditions and night time conditions. This provides an external layer of material for the item of clothing which may also include an internal mesh layer. 
     In this embodiment, the loom  401  is restrained substantially behind the reflective tape  502 . A control unit is supported within an internal pocket for receiving the loom connector  406 . The control unit may be activated without it being removed from this pocket by manual pressure applied at an indicator  503 . The fourth device strip  404  supports a fourth device group  504  and the first device strip  402  supports a first device group  511 . 
     FIG.  6   
     A rear view of the vest described with reference to  FIG. 5  is illustrated in  FIG. 6 . A second set of devices  602  are supported by the third device strip  403 . The loom then extends beneath a horizontal portion  603  to connect to a third device group  613  supported by the first LED strip  303 . 
     FIG.  7   
     In accordance with an aspect of the present invention, it is desirable for the device strips to be protected as much as possible and for the light-emitting devices to be protected, while at the same time allowing light to be emitted. An embodiment therefore provides a solution by retaining the bulk of the device strips behind the reflective tape, while providing transparent windows for the emission of light from these devices. In an embodiment, a clear flexible poly vinyl chloride material is adopted but other suitable materials with appropriate flexibility could also be used. 
     The clear flexible poly vinyl chloride material is secured by applying an adhesive film to an inside surface of a clothing fabric. An example of a suitable film of this type is illustrated in  FIG. 7 . The adhesive film is a composite material that includes a mid-positioned barrier film  701 . 
     A lower surface of the barrier film  701  contacts with a lower adhesive layer  702 , which is in turn protected by a lower protective film  703 , possibly implemented as a layer of grease-proofed paper. Similarly, an upper surface of the barrier film  701  is in contact with an upper adhesive layer  704 , again protected by an upper protective film  705 . 
     To achieve adhesion, the lower protective film  703  is removed and the materials brought into contact. Adhesion is then achieved by the application of pressure and heat, resulting in the creation of a seal that is mechanically strong and watertight. 
     FIG.  8   
     An inside surface  801  of a clothing fabric is illustrated in  FIG. 8 . The adhesive film, described with reference to  FIG. 7 , is located over a portion of this inside surface after the first protective film  703  has been removed. The adhesive film is then retained in place by the application of heat and pressure, as illustrated by the application of iron  802 . 
     FIG.  9   
     After the barrier film  701  has been secured to the inside surface of the clothing fabric, a template  901  is located over the second protective film  705 . The template  901  includes a first hole  911 , a second hole  912  and a third hole  913 . The spacing between these holes  911  to  913  is compatible with the spacing between individual light-emitting devices within a device group. Thus, the holes  911  to  913  define the position of windows for the light-emitting devices. 
     FIG.  10   
     After the application of the template  901 , as described with reference to  FIG. 9 , a power drill  1001  is deployed to perform a twist cutting operation at the location of each hole  911  to  913 . A twist cutting operation is used to create clean cut holes through the second protective film  705 , the upper adhesive layer  704 , the barrier film  701 , the adhered fluorescent material  501  and the reflective tape  502 . 
     FIG.  11   
     After twist cutting the three holes through the adhesive film, the second protective film  705  is removed, such that the adhesive film now presents the unprotected upper adhesive layer  704  for the reception of a clear plastics material, as described with reference to  FIG. 12 . 
     FIG.  12   
     A clear plastics material  1201  includes a central portion  1202 , a first flap  1203  and a second flap  1204 . 
     The central portion  1202  of the clear plastics material  1201  is positioned over the first hole  911 , the second hole  912  and the third hole  913  to define respective windows, comprising a first window  1211 , a second window  1212  and a third window  1213 . 
     FIG.  13   
     In an embodiment, a gasket  1301 , possibly constructed from a foam-based material, is secured by the upper adhesive layer  704 . The gasket  1301  includes a first gasket hole  1311 , a second gasket hole  1312  and a third gasket hole  1313 . Gasket holes  1311  to  1313  line up with respective windows  1211  to  1213 . 
     FIG.  14   
     The device strip  303  is located over the gasket  1301 . The first gasket hole  1311 , the second gasket hole  1312  and the third gasket hole  1313  provide an interference fit for the first light-emitting device  111 , the second light-emitting device  112  and the third light-emitting device  113  respectively. 
     Thus, the light-emitting devices  111  to  113  are retained within respective gasket holes  1311  to  1313  by an application of pressure in the direction of a second arrow  1401 . 
     FIG.  15   
     After the light-emitting devices have been received within the holes defined within the gasket  1301 , as described with reference to  FIG. 14 , in an embodiment, a protective layer  1501  is deployed over the device strip  303 . 
     In accordance with an aspect of the present invention, the first flap  1203  is folded over a rear surface of the substrate (the flexible printed circuit board  101 ) which, in this embodiment, places the first flap  1203  in contact with the protective layer  1401 . Thereafter, again in accordance with an aspect of the present invention, the second flap  1204  is further folded over the folded first flap  1203 . Furthermore, the whole assembly is made secure and watertight by attaching the further folded second flap to the folded first flap. 
     FIG.  16   
     A cross section on line XVI-XVI is shown in  FIG. 16 , illustrating a fully assembled example of the apparatus. The apparatus therefore provides for the embedding of light-emitting devices connected to a loom of power and data cables and supported on a substrate, within an item of clothing having a strip of a reflective tape surrounded by a fluorescent material. A respective window  1213  is provided for each light-emitting device  113 . A hole has been cut through the reflective tape  502  and is covered by a clear plastics material  1201  that defines a first flap  1203  and a second flap  1204 . 
     The first flap  1203  has been folded around the substrate and the substrate is secured by the second flap  1204 ; by the second flap having been further folded around the first flap  1203 . The clear plastics material  1201  is secured to the clothing fabric  502 , by the adhesive film  701  through which the holes have also been cut. 
     In this embodiment, the substrate is a flexible printed circuit board  101 . The adhesive film comprises a central barrier layer  701 , with reflective tape being adhered thereto by means of a first adhesive layer  702  and the clear plastics material  1201  being adhered thereto by means of an upper adhesive layer  704 . 
     In this embodiment, the gasket  1301  surrounds the light-emitting device  113 . The embodiment also includes a protective layer  1501  and an adhesive film  1601  is provided between the first flap  1203  and the second flap  1204  to fully secure the second flap  1204  to the folded first flap  1203 .