OA10757A - Illuminated sign and sign plate therefor - Google Patents

Abstract

illuminated signs and their boards. SUBSTANCE: edge-illuminated sign has light source and transparent sheet one of whose edges is placed near light source. The latter passes light beam along transparent sheet whose front surface carries displaying layer provided with backward-directed reflecting surface and whose rear surface has rear display layer which actually coincides with front one. EFFECT: reduced manufacturing cost, enhanced light intensity of sign, enlarged variety of images displayed. 10 cl, 6 dwg

Description

1 010757

ILLUMINATED SIGN AND SIGN PLATE THEREFOR

The présent invention relates to an illuminated signand to a sign plate for an illuminated sign.

Edge-i1luminated signs are known in which a transparentplastics sheet ’is illuminated by a light source disposedalong one edge thereof so that light passes through thesheet material in a direction along the plane of the sheet.An image to be displayed is formed on one of the faces ofthe sheet whereby the light contrast between the image andthe remainder of the sheet increases the visual impact ofthe image to a 'person viewing the sign. A typical knownedge-illuminated sign is illustrated in Figure 1.

Referring to Figure 1, a transparent plastics sheet 2,typically of acryiic plastics material, which is rectangularin shape has one edge 4 thereof receivec in a lamp housir.g 6elongate bulb 7, typically a fluorescent bulb,s 9 tnerefor are received, the bulbexte.nding substantially along the length of the edge 4. Inuse, an end cap* 8 is fitted over each end 10 of the lamphousing 6. In Figure 1, which is a partially exploded view,one end cap 3 is shown in its removed configuration and thebulb and electrical fittings 9 are partially removed so thatthe edge 4 of the sheet 2 is readily visible. The sheet 2is provided either on its frontmost face 12 or its rearmostface 14, the direction being with respect to the intendedthe sign, wnicr an oos: :lectrical fittings 9 with an image 15

The : ion or a viewer o; * image 15 may be formed by engraving the surface'of the sheet2 or by printing a partially transmissive printed 'ink layeron the surface of the sheet, for example by screenprinting. When the bulb 7 is illuminated, light emittedfrom the bulb 7 passes along the sheet 2 from the edge 4 andis internally reflected at the sheet/air interfaces. whenthe image 15 is engraved, light passing along the sheet 2 isreflected and refracted at the engraved edges thereb}illuminating the edge of the image 15. When the image 15 r 2 010757 printed, the internally reflected light is incident on therear surface of the image 15 and is partially transmitted tothe front surface of the image 15 thereby to provide anilluminated image.

When the image is engraved this increases the cost andcomplexity of manufacture of the illuminated sign. when the .image is printed, the degree of contrast of the image is notparticularly high and so the sign is not particularlyeffective in ambient conditions of high light intensity.Furthermore, for both prior arrangements the nature of theimages which can be conveyed by the signs is relativelylimited. US-A-5009019 and WO-A-93/07605 are both in the name ofthe présent inventor and relate to sign plates forilluminated signs. Both of these prior spécificationsdisclose a sign plate for an illuminated sign which isintended to be illuminated by a light source disposed behinda rearmost face of the sign plate.

An aim of the présent invention is to provide animproved edge-i1luminated sign. It is a further aim of theprésent invention to provide an edge-illuminated sign whichcan be manufactured cost-effectively and can provideenhanced illumination of the image as compared to knownedge-illuminated signs. It is a further aim of the présentinvention to provide an edge-illuminated sign which enablesa wide variety of images to be displaved.

Accordingly, the présent invention provides anilluminated sign comprising a light source, a transparentsheet having one edge thereof which one edge is assembledadjacent the light source for receiving light therefromwhich, in use, is transmitted along the transparent sheet, afront image layer which is disposed on a front face of the- 3 010757 transparent sheet and has a rearwardly-directed reflectivesurface and a rear image layer which is disposed on a rearface of the ,t'ransparent sheet substantially in registry withthe front image layer whereby, in use, light is reflectedfrom the reflective surface onto the rear image layerthereby to enhance the illumination of the rear image layer.

The présent invention further provides a sign plate foran edge-i1luminated sign, the sign plate comprising atransparent sheet having one transparent edge thereof forreceiving from a light source light for transmission alongthe transparent sheet, a front image layer which is disposedon a front face of the transparent sheet and has arearwardly-directed reflective surface and a rear imagelayer which is disposed on a rear face of the transparentsheet substantially in registry with the front image layerwhereby, in use, light is reflected from the reflective surface onto the rear image layer thereby to enhanceillumination of the rear image layer. :he

Fmbodiments of the présent invention will now bedescribed by way of example only, with reference to theaccompanying drawings, in which:-

Fig. 1 is a partially exploded perspective view of aknown edge-illuminated sign;

Fig. 2 is a perspective view of an edge-illuminated sign in accordance with a first embodiment of the présent invention ; Fig . 3 i s a cross-secti on on line’ A-A o f the edge-illumina ted si gn illustrated i n F i g . 2 ; Figs. 4 & 5 are schematic views similar to that of

Figure 3 illustrating the mechanism of the transmission oflight along and out of the transparent plastics sheet of thesign illustrated in Figure 2; and

Fig. δ is a cross-section through an edge-illuminated sign in accordance with a second embodiment of the présent invention. 4 010757 13 SuOWIl 3Πas 20, inthe présent invention.form of ahousing 22 fluorescent bulblamp housing 22.lower surface withwhich receives theplastics sheet

Referring to Figures 2 and 3, thereedge-illuminated sign, designated generallyaccordance w'ith a first embodiment of

The sign 20 comprises a lamp housing 22 in thecvlindrical tube. At opposed ends of the lampare provided electrical fittings 24 for a26 which extends along the length of theThe lamp housing 22 is provided an axially directed elongate slotuppermost edge 30 of a .transparentwhich is supported by and dépendslamp housing 22. In the illustrated in its28 32 downwardly from the embodiment, the transparent plastics sheet 32 is rectangular in shape, havinglowermost edge 38. :wo upright, side edges 34,36 and

As is shown clearly in Figure 3, the lowermost edge 38is inclined to the plane of the sheet 32 with the internaiface of the edge 33 facing towards the front face 40 andaway from the rear face 42 of sheet 32. The inclined edge38 is preferably at an angle of less than about 45° to aline perpendicular to the sheet 32 so that light isreflected back from the edge 38 into the sheet 32 at arelatively low angle so as to subsequently be internallyreflected back up through the sheet 32 with minimal loss oflight intensity. In an alternative arrangement, theinclined edge 38 faces towards the rear face 42 rather thanthe front face 40. The front face 40 of the sheet 32 iscoated with a front image layer 44 which is patterned in theshape of an image to be displayed by the sign 20 (in theillustrated embodiment, the letter A which is shown merelyby way of example) . The rear face 42 of the sheet 32 iscoated with a correspondingly shaped rear image layer 46which is disposed in registry with the front image layer44. in the illustrated embodiment, the width of the rearimage layer 46 (in the plane of the layer 46) isdimensionally larger than that of the front image layer 44 5 010757 an

The whereby the rear image layer 46 defines, in régions such asrégions 48,50,52,54 illustrated in Figure 3, a peripheralmargin 56 su'rrounding and highlighting the image conveyed bythe front image layer 44. The front image layer 44 has arearwardly directed surface 58 which is reflective.Preferably, the front image layer 44 comprises aself-adhesive· plastics (e.g. vinyl) film which hasunderlying self-adhesive reflective surface 58. plastics film may be fluorescent and translucent. The frontimage layer 44 or its reflective surface may be provided bya metallic and/or brightly coloured (e.g. white) paint layeror by a metallised or brightly coloured coating on or in theplastics film. The paint layer 44 may be fluorescent and atleast partiallv translucent. The front surface 60 of such afront image layer 44 may hâve been provided suitable colour, pattern or image, either by such pattern or image being présent in the film or having beenapplied thereto. The front image layer 44 may alternativelycomprise a printed film of any desired colour or colours. image layer 46 comprises a layer of fluorescentof any desired colour or combination of colours which preferably has been printed, for example by screenprinting, onto

Preferably, thetransmissive forembodiment, the with anya colour,

The rearmaterial the rear face 42 ofrear image layer 46visible light. Inrear image layer may the sheet 32. is partiallyan alternativecomprise a self-adhesive plastics (e.g. vinyl) film which is preferablyfluorescent and translucent. The front and rear imagelavers may incorporate phosphorescent materials. A backing sheet 62 is mounted behind and parallel withthe sheet 32. The backing sheet 62 has a front face 64which is pre.ferably spaced slightly from the rear face 42 ofthe sheet 32. The backing sheet 62 preferably comprises asubstantially opaque plastics sheet having a desired colourand/or a fluorescent coating. The backing sheet 62 may hâveany desired image or pattern or the front face 64 or the 6 010757 rear face 66 thereof when the backing sheet 62 istranslucent. Alternatively, the backing sheet 62 maycomprise a transparent plastics sheet having a substantiallyopaque coating on the front face 64. The lamp housing 22 isconfigurée! to provide a mount 68 for the upper eàge 70 ofthe backing sheet 62. A bottom mount 72 is provided alongthe respective adjacent bottom edges 38,74 of thétransparent sheet 32 and the backing sheet 74. Preferably,the inner surface 76 of the bottom mount 72 which abuts theinclined bottom edge 38 of the transparent sheet 32 isreflective. As shown schematica1ly in Figure 3, clampingdevices 78,80 may be provided for holding together theassembly of the transparent sheet 32 and the backing sheet62.

The operation of the edge-i 1 luminated sign 20 wi 11 nowbe described with reference to Figures 4 and 5.

In use, the fluorescent bulb 26 is illuminated and asshown in Figure 4, light beams, such as light beam 82, whichare not parallel to the plane of the transparent sheet 32are transmitted through the plane of the sheet 32 byinternai reflection at alternatively the inner and outerfaces 40,42 of the transparent sheet 32. It will be seenthat since in the illustrated embodiment the only layerswhich are formed on the front and rear faces 40,42 of thetransparent sheet 32 are the front and rear image layers44,46, there is an enhanced degree of internai reflection oflight being transmitted along the sheet 32, the light beinginternally reflected at the s'neet/air interfaces. Ifadditional layers were présent intimately covering the sheetfaces, then the degree of internai reflection would bereduced because light would be asborbed into these additionallayers, thereby reducing correspondingly the level ofillumination of the desired image. For this reason, thebacking sheet 62 may be adjacent to, but not ahdered orotherwi se intimately connected, bonced or adhered to the 010757 transparent sheet because this would reduce the total amount of light internally reflected in the transparent sheet.

As shown in Figure 5, any light beam 84 which isparallel to the plane of the transparent sheet 32 istransmitted down the entire length of the sheet 32 andsubsequently reflected by internai reflection at théinclined face 38, or reflected by reflection at thereflecting face 76 of the lower mount 72, and the reflectedbeam 86 is transmitted back up the transparent sheet 32 andsubsequently internally reflected at the inner and outerfaces 40,42 of the transparent sheet 32. In this way, lightfrom the bulb 26 is transmitted throughout the whole body ofthe transparent sheet 32.

Light beams which are not parallel to the plane of thetransmitting sheet 32 are reflected to a significant extentat the reflective surface 58 of the front image layer 44.This reflected light (e.g. at arrow 88) is reflected to asignificant extent back onto the fluorescent rear imagelayer 46. This provides an enhanced illumination of thefluorescent rear image layer 46 so that the edges of therear image layer 46 which are not directly covered by (i.e.are at least partially exposed by) the front image layer 44appear very bright to a viewer of the sign (e.g. at arrow90). This brightness is enhanced by the fluorescent effectof the rear image layer 46 which strongly emits fluorescentradiation as a resuit of being illuminated by light from thebulb 26. The overall illumination effect to a viewer of thesign 20 is a strongly illuminated fluorescent annular borderor highlight surrounding the image defined by the frontimage layer 44. This provides an illuminated outline atleast partially around indicia defined by the front imagelayer.

T

The front image layer 44 may be substantially opaque or partially transmitting. If the front image layer 44 is 8 010757 partially transmitting, then as shown in Figure 4 some light(e.g. at arrow 92) is reflected from the rear face 42 of thesheet 32 forw'ardly through the front image layer 44 wherebythe image defined by the front image layer 44 is partiallyi1luminated.

The fluorescent layer 46 is partially transmitting andaccordingly light (e.g. at arrow 94) passes rearwardlythrough the fluorescent layer 46 and onto the backing sheet62. Such light is reflected from the backing sheet 62 atits front face 64 (e.g. at arrow 94) and such reflectedlight is transmitted forwardly through the transparent sheet32. Such reflected light from the backing sheet 62 providesan image of a halo or aura of , light surrounding the imagedefined by light reflected from the fluorescent rear imagelayer 46. The halo of light is illustrated in Figure 1.The colour of the halo of light is preferably the same asthat of the fluorescent rear image layer 46. The colour maybe varied by applying an additional coloured layer to theback of the rear image layer or to the front of the backingsheet. The latéral width of the halo may be varied byaltering the spacing between the transparent sheet 32 andthe backing sheet 62. A further embodiment of an illuminated sign 90 inaccordance with the présent invention is illustrated inFigure 6 which is similar to the embodiment illustrated inFigures 2 to 5 except that the opaque backing sheet 62 is reolaced bv transparent backing sheet 96 having reflecting coating 98 on its rear face 100. The reflectingcoating 94 comprises a self-adhesive plastics film 102having a reflecting front surface 104. Alternatively, thereflecting co-ating 94 is a printed layer. In a similarmanner to that illustrated in and described with referenceto Figures 4 and 5, a halo effect is provided around the.fluorescent rear image layer 46 by light being reflected offthe reflecting surface of the film 98 (e.g. at arrow 106). 9 010757

Since the reflecting film 102 is on the face 100 of thebacking sheet 96 which is remote from the transparent sheet32, there is-'no requirement for the backing sheet 96 to bespaced in order to provide a visible halo effect.

It will be apparent to those skilled in the art thatvarious modifications can be made to the illustratedembodiments within the scope of the invention. In theillustrated embodiments, the front image layer lies whollywithin the latéral periphery of the rear image layer so thata peripheral highlight is defined by a border portion of therear image layer which surrounds the front image layer. Inalternative embodiments, although the rear image layer wouldgenerally be in registry with ,the front image layer, therear image layer may be laterally offset relative to thefront image layer or may hâve smaller dimensions than thefront image layer on one side thereof so as to provide ahighlight which is offset and does not extend ail the wayaround the periphery of the front image layer. Thus thehighlight may appear as a highlignted "shadow" on one sideof the image defined by the front image layer. In a furtherembodiment, the front and rear image layers may be alignedand hâve the same size and shape. With this embodiment ahighlight or cutline can be seen by a viewer looking at thesign at an angle.

In the embodiments of the invention, the front and rearimage layers are separated by a distance corresponding tothe thickness of the transparent sheet. When the front andrear image layers are illuminated in the mahner describedhereinabove, the viewer is able to detect a spacialdifférence between the front and rear image layers. Thiscréâtes a three dimensional effect whereby the front andrear image layers appear to be connected by an inclinededge, giving the overall indicia a massive and solid,appearance. The thickness of the three dimensional imagecorresponds te the thickness of the transparent sheet. The 10 010757 shape and angle of inclination of the inclined edge can bevaried by altering the relative sizes and disposition of thefront and rea'r image layers. For example, if the rear imagelayer is slightly larger in latéral dimension than the frontiamge layer ail around its periphery, then a relativelysteep inclined edge will be apparent to a viewer of the signwhen the sign is illuminated.

The images to be conveyed may comprise alphanumericcharacters or other pictorial images. The front -image layermay itself be printed or otherwise provided with images onits front surface.

Although the transparent' sheet is illustrated asdepending downwardly from the lamp housing 22, inalternative configurations the lamp housing may be providedbeneath the transparent sheet and may constitute a supportstand for the entire sign. In addition, although theillustrated embodiments utilise a fluorescent bulb as thelight source for the illuminated sign, any other suitablelight source may be employed, for example an incandescentbulb, a néon bulb, etc..

In alternative embodiments, a light reflectiveself-adhesive plastics layer, for example white or silver incolour, is adhered over the edge of the sheet which isremote from the light source in order to reflect light backthrough the sheet. The mount along that edge may be squarerather than inclined, particularly for small dimension signs.

In accordance with the invention, the provision of afluorescent layer at least partially surrounding the frontimage layer on the transparent sheet, together with theprovision of a reflecting surface on the rear of that frontimage layer, provides real technical advantage as opposed toedge-illuminated signs in the prior art by forming an 11 010757 illuminated image having a relatively high intensity. Thismeans that the edge-illuminated sign is clearly visible to aviewer even in relatively high intensity ambient light andwhen the sign is intended to be seen from a substantialdistance away. The sign of the présent invention also hasgreat flexibiilty in use by enabling a wide variety ofvisual effects· to be reproduced. For exampl.e different'colours can be displayed with or without fluorescentlayers. An aura of one or more colours may wholly orpartially surround the indicia. The colour, size, shape andorientation of a highlight around the indicia may beselected as desired. Printed or patterned images definingor surrounding the indicia may be provided. The sign can bemanufactured very cost effectively by using known printingtechniques and known techniques for applying patternedself-adhesive plastics fi 1ms to rigid plastic sheets in therequired positions.

The provision of a light reflection device at the edgeof the sheet which is away from the light source ensuresthat the amount of light internally reflected in the sheetto cause illumination of the indicia is substantiallymaximised. This not only increases the visibility of thesign but also provides even and uniform illumination of theindicia on both sides thereof, i.e. on the sides which arenear to and remote from the light source.

Claims (42)

12 010757 CLAIMS:

1. An illuminated sign comprising a light source, atransparent sheet having one edge thereof which one edge isassemblée adjacent the light source for receiving lighttherefrom whi'ch, in use, is transmitted · along thetransparent sheet, a front image layer which is disposed ona front face of the transparent sheet and has arearwardly-directed reflective surface and a .rear imagelayer which is disposed on a rear face of the transparentsheet substantially in registry with the front image layerwhereby, in use, light is reflected from the reflectivesurface onto the rear image layer thereby to enhance theillumination of the rear image layer.

2. An illuminated sign according to claim 1 wherein thefront image layer comprises a self-adhesive plastics film.

3. An illuminated sign according to claim 1 wherein thefront image layer comprises a printed film.

4. An illuminated sign according to any one of daims 1 to3 wherein the front image layer is partially transmissive.

5. An illuminated sign according to any foregoing claimwherein the rear image layer comprises a fluorescent layer.

6. An illuminated sign according to claim 5 wherein the fluorescent layer comprises a self-adhesive plastics film.

7. An illuminated sign according to claim 5 wherein the fluorescent layer comprises a printed film. 3· An illuminated sign according to any foregoing claim wherein the front image layer and the rear image layer are mutually shaped and oriented whereby the front image layer at least parriallv exposes the rear image laver therebehind. 13 010757

9. An illuminated siqn according to cia im 3 wherein an annular peripheral portion of the rear image layer surrounding the front image layer i s exposed by the front image layer. 10. An illuminated sign according to daim 8 wherein the front image layer is laterally offset with respect to the rear image layer. 11. An illuminated sign according to any fore.going daim wherein the front and rear image layers are dimensioned andpositioned with respect to each other so as to provide anilluminated outline at least partially around indiciadefined by the first image layer,.

12. An illuminated sign according to any foregoing claimfurther comprising a backing sheet located rearwardly of therear face of the transparent sheet.

13. An illuminated sign according to claim 12. wherein thebacking sheet is opaque.

14. An illuminated sign according to claim 12 wherein thebacking sheet comprises a second transparent sheet carryingan opaque layer.

15. An illuminated sign according to claim 14 wherein theopaque layer is disposed on a rear face of the secondtransparent sheet.

15. An illuminated sign according to any one of daims 12to 15 wherein the front face of the backing sheet is spacedfrom the rear .face of the transparent sheet.

17. An illuminated sign according to any one of daims 12.to 16 wherein the rear image layer is partially transmissivewhereby, in use, light transmitted therethrough onto the 14 010757 backing sheet créâtes an illuminated aura around the rearimage layer.

18. An illuminated sign according to any foregoing claimwherein a second edge of the transparent sheet which isopposite the said one edge is adapted to reflect light backinto the transparent sheet.

19. An illuminated sign according to claim 18 wherein thesecond edge is inclined to the plane of the .transparentsheet.

20. An illuminated sign according to claim 19 wherein thesecond edge is inclined at an -angle of up to about 45° toa line perpendicular to the plane of the transparent sheet.

21. An illuminated sign according to any one of daims 18to 20 further comprising a reflecting member which coversthe second edge thereby to reflect light into the sheet.

22. An illuminated sign according to claim 21 whenappendant on any one of daims 12 to . 17 wherein thereflecting member comprises a mount for the transparentsheet and the backing sheet.

23. A sign plate for an edge-illuminated sign, the signplate comprising a transparent sheet having one transparentedge thereof for receiving from a light source light fortransmission along the transparent sheet, a front imagelayer which is disposed on a front face of th’e transparentsheet and has a rearwardly-directed reflective surface and arear image layer which is disposed on a rear face of thetransparent sheet substantially in registry with the frontimage layer whereby, in use, light is reflected from thereflective surface onto the rear image layer thereby toenhance the illumination of the rear image layer. 15 010757

24. A sign plate according to daim 23 wherein the frontimage layer comprises a self-adhesive plastics film.

25. A sign plate according to claim 23 wherein the frontimage layer comprises a printed film.

26. A sign plate according to any one of daims 23 to 25wherein the front image layer is partially transmissive.

27. A sign plate according to any one of daims 23 to 26wherein the rear image layer comprises a fluorescent layer.

28. A sign plate according to daim 27 wherein the fluorescent layer comprises a s,elf-ad'nesive plastics film.

29. A sign plate according to claim 27 wherein the fluorescent layer comprises a printed film.

30. A sign plate according to any one of daims 23 to 29wherein the front image layer and the rear image layer aremutually shaped and oriented whereby the front image layerat least partially exposes the rear image layer therebehind.

31. A sign plate according to daim 30 wherein an annularperipheral portion of the rear image layer surrounding thefront image layer is exposed by the front image layer.

32. A sign plate according to claim 30 wherein the frontimage layer is laterally offset with respect to the rearimage layer.

33. A sign plate according to any one of daims 23 to 32wherein the front and rear image lavers are dimensioned andpositioned with respect to each other so as to provide anilluminated outline at least partially around indiciadefined by the first image layer. 16 010757

34. A sign plate according to any one of daims 23 to 33further comprising a backing sheet located rearwardly of therear face of the transparent sheet.

35. A sign plate according to claim 34 wherein the backingsheet is opaque.

36. A sign plate according to claim 34 wherein the backingsheet comprises a second transparent sheet carrying anopaque layer.

37. A sign plate according to claim 36 wherein the opaquelayer is disposed on a rear face of the second transparentsheet.

38. A sign plate according to any one of daims 34 to 37wherein the front face of the backing sheet is spaced fromthe rear face of the transparent sheet.

39. A sign plate according to any one of daims 34 to 38wherein the rear image layer is partially transmissivewhereby, in use, light transmitted therethrough onto thebacking sheet créâtes an illuminated aura around the rearimage layer.

40. A sign plate according to any one of daims 23 to 39wherein a second edge of the transparent sheet which isopposite the said one edge is adapted to reflect light backinto the transparent sheet.

41. A sign plate according to daim 40 wherein the secondedge is inclined to the plane of the transparent sheet.

42. A sign plate according to claim 41 wherein the secondedge is inclined at an angle of up to about 45° to a lineperpendicular to the plane of the transparent sheet. 010757 17

43. A sign plate according to any one of daims 40 to 42further comprising a reflecting member which covers thesecond edge thfereby to reflect light into the sheet.

44. A sign plate according to claim 43 when appendant onany one of daims 34 to 39 wherein the reflecting membercomprises a mount for the transparent sheet and .the backing'sheet. ’

45. An illuminated sign substantially as hereinbeforedescribed with reference to Figures 2 to 5 or Figure 5.

46. A sign plate for an edge-illuminated sign substantiallyas hereinbefore described with reference to Figures 2 to 5or Figure 6.