Patent Publication Number: US-2011051395-A1

Title: Signage

Description:
FIELD OF THE INVENTION 
     The present invention relates to signage and, particularly, to signage including lighting for illuminating the signage. 
     BACKGROUND OF THE INVENTION 
     Conventional methods of illuminating signage include placing lighting behind transparent or translucent materials (so-called “rear-lit” or “back-lit”) or along an edge of the material (so-called “edge-lit”). 
     Edge-lit displays are characterized by a large square or rectangular panel shape with fluorescent, neon or light emitting diode (LED) lighting disposed along the edges of the square or rectangle. As a result, illumination of central regions of the display is less than perimeter regions in closer proximity to the lighting. 
     Furthermore, such edge-lit displays are unsuitable for illuminating only selected sections of a panel. For example, providing relatively even illumination of text without illuminating areas surrounding the text is not economically feasible. 
     Selective illumination of text can be achieved with back-lit displays. However, even illumination is a problem. 
     Specifically, if a display to be illuminated is placed too closely to a light source, the display appears brighter in areas closer to the light source and darker in areas that are spaced further away. Even illumination is typically achieved by spacing the display from a light source by a distance that allows adequate light dispersion. 
     Accordingly, back-lit displays are typically built as light boxes and have a considerable depth aspect to allow adequate spacing of the light source and the material. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide more compact illuminated signs than signs formed according to conventional edge-lit and back-lit forms. 
     Advantageously, the invention may provide improved illumination evenness. 
     The invention provides a sign for illumination by a source of illumination, the sign comprising:
     (a) a light transfer apparatus having an illuminable portion with spaced apart opposed first and second sides, the illuminable portion having an outline shape that includes straight line segments interposed by corners and/or includes curves and having a light transmission wall with a shape that corresponds generally to the shape of the illuminable portion and that is located at least part way between the first and second sides;   (b) a source of illumination arranged to follow closely the shape of the light transmission wall along at least part of the wall and is arranged to direct light into the light transfer apparatus in a direction generally parallel to the first and second sides; and   (c) a light reflective apparatus associated with the second side for reflecting light from the source of illumination outwardly via the first side, thereby causing illumination of the illuminable portion.   

     Arranging a light source to follow a shaped outline of a portion of a display that is to be illuminated brings the source of illumination closer to the portion. This has a significant impact on the size of signs because shaping the light source to follow the shape of the illuminable portion enables the sign to be formed in the shape of the illuminable portion, rather than a large square or rectangular panel. Furthermore, providing illumination via an edge of the portion to be illuminated enables the spacing between the front of the sign and the source of illumination to be considerably reduced compared with back-lit signs. 
     Shaping the light source to follow the shaped outline of a display, in combination with a reflective medium on the rear side of the display, improves evenness of illumination because illumination of the sign is not reliant upon light travelling directly from the source of illumination outwardly from the sign. 
     Preferably, the light transfer apparatus of the sign is solid. 
     With a solid light transfer apparatus, light from the source of illumination will be subject to some internal reflection from an interface at the first and second sides. The reflected light travels through the light transfer apparatus away from the light source until it reflects off the light reflective apparatus and is transmitted outwardly via the first side. In this manner the internal reflection improves evenness of illumination in an area close to the light source and improves illumination in areas away from the light source. The overall result is improved evenness of illumination across the sign. 
     Preferably, the shape of the light transmission wall corresponds substantially to the outline shape of the illuminable portion. 
     Preferably, the shape of the light transmission wall corresponds to the outline shape of the illuminable portion. 
     The light transfer apparatus has a perimeter wall extending between the first and second sides and the light transmission wall may comprise the perimeter wall. 
     Preferably, the light transfer apparatus includes a channel for receiving the source of illumination and that closely follows the perimeter wall to define an inbound region of the light transfer apparatus, and wherein an interface between the channel and the inbound region comprises the light transmission wall. 
     Preferably, the channel is located adjacent to the perimeter wall and closely follows the perimeter wall to define an inbound region and an outbound perimeter region between the channel and the perimeter wall and wherein an interface between the channel and the inbound region comprises the light transmission wall. 
     In one embodiment, the source of illumination may be arranged to direct light into the inbound region and the outbound region and wherein interfaces between the channel and the respective inbound and outbound regions comprise light transmission walls. 
     Preferably, the channel is formed to receive the source of illumination. 
     Preferably, the source of illumination comprises a plurality of lighting elements disposed at regular intervals along a strip. 
     Preferably, the strip is flexible so the strip is locatable within the channel to conform with at least a segment of the channel shape that includes a corner and/or curve. 
     Preferably, the lighting elements are light emitting diodes. 
     Preferably, the light emitting diodes are able to produce multiple colours of light to illuminate the sign in a corresponding colour. 
     Preferably, the light reflective apparatus associated with the second side comprises a material which, when placed in contact with the second side, substantially excludes air at an interface between the material and the second side so that light passing through the second side is reflected back into the light transfer apparatus. 
     Preferably, the light reflective apparatus is selected from the following group: a layer of paint, self-adhesive materials, including vinyl film, and a material with a film of a liquid disposed between the material and the second side. 
     Preferably, the light transfer apparatus has an outline shape corresponding to the shape of an indicium, such as a letter, number, symbol or figure, and the outline shape includes straight line segments interposed with corners and/or includes curves. 
     Preferably, the light transfer apparatus is formed of transparent and/or translucent material. 
     Preferably, the sign includes a diffuser located over the first side for dispersing light emitted from the first side. 
     The diffuser operates to improve even dispersion of light from the sign. 
     Preferably, the diffuser is fixed to the light transfer apparatus. 
     Preferably, the diffuser comprises a translucent material. 
     The translucent material may be colored or may be coated with translucent colored members, such as colored vinyl sheet or vinyl sheet carrying a printed image. 
     The sign my be made to any thickness greater than 5 mm. Preferably, the sign has a thickness in the range of 5 to 80 mm. 
     The invention provides a sign for illumination by a source of illumination, the sign comprising:
     (a) a light dispersion apparatus having a outline shape defined by a shaped perimeter wall;   (b) a source of illumination arranged to transmit light into the light dispersion apparatus via the shaped perimeter wall, whereby the light dispersion apparatus is illuminable by the source of illumination; and
 
wherein the sign has a thickness in the range of 5 to 80 mm.
   

     Preferably, the sign has a thickness less than 40 mm. 
     Preferably, the sign has a thickness less than 20 mm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a front perspective cut-away view of a sign in accordance with an embodiment of the invention. 
         FIG. 2  is a cross-section along the line II-II in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     A sign  10  in accordance with an embodiment of the invention is shown in  FIGS. 1 and 2 . 
     The sign  10  comprises a light transfer apparatus, in the form of transparent acrylic  24 . The acrylic  24  has first and second sides in the form of front and rear surfaces  12  and  14  and a perimeter comprising a shaped edge wall  16  that defines the shape of the acrylic  24 . 
     The sign further comprises a light reflective apparatus in the form of a vinyl layer  34  disposed on a rear surface  14  of the acrylic  24  to reflect light incident upon the rear surface  14  back into the acrylic  24  and, typically, out the front surface  12 . 
     The sign further includes a diffuser in the form of a translucent acrylic layer  28 . The acrylic layer  28  disperses incident light from the acrylic  24  outwardly from the sign  10 . The translucent acrylic layer  28  has the effect of reducing contrast between areas of bright light and areas of less bright light so the overall illumination effect is to provide relatively even illumination from the sign. 
     Although not shown in  FIGS. 1 and 2 , the acrylic layer  28  may be covered with a translucent or transparent vinyl film that is colored or on which images are printed. 
     The acrylic layer  24  includes a channel  18  formed in the rear side  14  for receiving a source of illumination. The channel  18  is formed adjacently to the perimeter wall  16  and defines a boundary between an inboard region  40  and an outboard region  42 . The channel follows closely the shape of the perimeter wall  16  and so is shaped correspondingly to the perimeter wall  16 . The specific shape of the channel  18  in the acrylic  24  is marked with dotted line in  FIG. 1 . 
     The sign  10  includes a source of illumination in the form of a flexible strip of LEDs  26  ( FIG. 2 ). The strip  26  comprises a substrate ribbon of including electrical conductor to which is mounted a series of LEDs at regular intervals. The strip  26  is located in the channel  18  and is arranged so that the LEDs direct light through a light transmission wall in the form of an interface  18 ′ between the channel  18  and the acrylic  24 . 
     Although shown directing light into the inboard region  40  of the acrylic  24 , the strip  26  may be arranged to direct light into the outboard regions  42  or into both the inboard and outboard regions  40  and  42 . 
     In some circumstances, the inboard region  40  is too wide to achieve suitable even illumination from lighting disposed in the channel  18 . The circumstances, however, depend on a number of factors, including the coloring of any layers over the first side  12 , spacing between the channels  18 , the normal brightness of LEDs on the strip and the intended brightness in the inboard region. Generally, the applicant recognises that a central channel located between the channels  18  may be required for two additional strips  26  in a back-to-back configuration. The central channel is parallel to the adjacent channels  18  and hence will have a shape that corresponds to the outline shape of the sign  10 . Accordingly, the central channel includes strips  26  shaped to conform to the shape of the sign  10 . 
     It should also be appreciated that in some circumstances, the channels  18  may be omitted in place of a central channel only with strips  26  arranged to direct light outwardly toward the perimeter wall of the acrylic  24 . 
     The vinyl layer  34  is disposed on the rear side  14  and assists to retain the strip  26  in the channel  18 . 
     Electrical conduits  44  are used to link the strips  26  to a source of electrical energy for illumination the sign  10 . 
     In one embodiment, the support apparatus may comprise a building wall with stand-off arms so that the sign  10  is spaced from the wall when mounted to the stand-off arms. In this embodiment, the sign  10  may be configured to allow light to emit from the rear side  14  to provide a halo illumination effect on the building wall. In such an embodiment, the vinyl layer  34  is formed to be translucent, but still with reflective properties to allow some light to move through the vinyl layer  34  onto the building wall and to reflect some light back into the acrylic  24 . 
     It will be appreciated that the width of the strip  26  has a large impact on the overall thickness of the sign  10 . The strip  26  may have a width of 4 mm or less. In such circumstances, the applicant recognises that illuminated signs may be formed with an overall thickness of at least 5 mm and anticipates signs having a thickness in the range of 5 to 80 mm, and, particularly, less than 40 mm in thickness and, more particularly, less than 20 mm in thickness. However, signs with a thickness greater than 80 mm may be formed, for example with the acrylic  28  spaced from the front side  12 . 
     Many modifications may be made to the preferred embodiment of the present invention as described above without departing from the spirit and scope of the present invention. 
     It will be understood that the term “comprises” or its grammatical variants as used in this specification and claims is equivalent to the term “includes” and is not to be taken as excluding the presence of other features or elements.