WO2002003363A2

WO2002003363A2 - An illuminated display device

Info

Publication number: WO2002003363A2
Application number: PCT/EP2001/007623
Authority: WO
Inventors: Robert John Hunt
Original assignee: Roddy, Norman, Stephen; Moir, Adrian, Gawain
Priority date: 2000-07-06
Filing date: 2001-07-03
Publication date: 2002-01-10
Also published as: GB0016532D0; AU2001287579A1; WO2002003363A3

Abstract

An illuminated display device comprise an image sheet including a plurality of series of image strips and a mask sheet (18) having alternate opaque and transparent strips, the mask sheet being located in face-to-face relation to the image sheet. At least one pair of drive rollers, (22, 24) having substantially parallel axes are attached respectively to opposite edges the mask sheet. A mechanism for oscillating the mask sheet relative to the image sheet by driving the pair of rollers in synchronism alternately in opposite directions comprises a rotary cam (50), a pair of cam followers (58, 60), a respective crank lever (76) associated with each drive roller, and a linkage mechanism (72, 74) connecting the crank lever to the cam follower.

Description

AN ILLUMINATED DISPLAY DEVICE

The present invention relates to an illuminated display device for displaying an image from a series of image portions on an image sheet. The invention has particular application for, but is not limited to, "point of sale" or "commercial poster advertising".

There are known illuminated display devices which illuminate an image sheet, for example, an ink jet print or a photographic print, the image sheet comprising two series of image portions in strip form strategically placed behind, or in front of, a mask sheet or grid, the mask sheet or grid having a series of transparent windows alternating with a series of opaque strips, either the mask sheet or the image sheet being moved so that the two series of image portions on the image sheet are aligned, in turn, with the series of transparent windows on the mask sheet, thereby permitting an image formed from one of the two series strip images to be visible.

It will be appreciated that the clarity of each of the two images, the change-over of the images and the dwell time on each of the images is of paramount importance to the advertiser. This is determined by the precision of both the assembly of the image sheet and the matching mask sheet and the drive means and tensioning means used to move the image sheet and the mask sheet relative to one another.

Previous designs, in both respects, have limited the dimensions of illuminated display devices and have been associated with significant drawbacks in terms of clarity of each of the visible images.

The present invention aims to overcome the limitations associated with known illuminated display devices and achieve an illuminated display device without the previous restrictions as to its dimensions and stability under varying atmospheric conditions. This enables the illuminated display device of the present invention to be used in all recognised sizes (for example, up to 1.5m wide and up to 3m high in both landscape and portrait formats) , thereby vastly increasing its potential customer base.

According to the present invention, there is provided an illuminated display device comprising an image sheet including a plurality of series of image strips; a mask sheet having alternate opaque and transparent strips, the mask sheet being located in face-to-face relation to the image sheet; at least one pair of drive rollers having substantially parallel axes attached respectively to opposite edges of one of the image sheet and mask sheet; and means to oscillate the one of the image sheet and mask sheet relative to the other of the image sheet and mask sheet by driving the pair of rollers in synchronism alternately in opposite directions, the driving means comprising a rotary cam, at least one cam follower associated with the cam, a respective crank lever associated with at least one of the drive rollers, and a linkage mechanism connecting the crank lever to the cam follower. Preferably the linkage mechanism comprises a pivoted cam follower support member and wherein the cam follower is pivoted to the support member and resiliently biased against the cam, the arrangement being such that rotation of the cam effects oscillation of the cam follower and, via the resilient biasing means, oscillation of the support member, the linkage mechanism further including means coupling the crank lever to the support member.

Preferably, the image sheet comprises at least three series of image portions, more preferably at least five series of image portions and most preferably up to ten series of image portions. It will of course be appreciated that the number of series of image portions is not limited to ten in number.

The illuminated display device of the present invention is suitable for interior and exterior displays. The illuminated display device of the present invention enables a number of images to be viewed in turn. Depending on whether the illuminated display device is for interior or exterior end use, the display device may be illuminated from different directions, for example, back-illuminated, side-illuminated or front- illuminated, the latter being by, for example, an external light source.

The visible image may comprise several separate images or, alternatively, several images creating a story line or, further alternatively, several images arranged to provide the perception of seamless animated movement or an animatic movement. Generally, depending on the size of the image, there will be a number of pairs of drive rollers, all driven in synchronism. The number of pairs of rollers is generally proportional to the width of the mask sheet, or image sheet. Thus, for example, one pair of rollers will be suitable for up to 500mm wide display units of the invention, whereas at least two pairs of rollers will be required on 800mm wide and above display units of the invention, although units of wider dimensions are also envisaged. The length of each drive roller is proportional to the distribution of tension of the mask sheet, or image sheet, so as to avoid distortion of the mask sheet, or image sheet, but has been found to work most advantageously at between 125-250mm in length. .

Where there are two or more pairs of drive rollers it is preferable that the rollers in all but one of the pairs are free to along their own axes to a limited extent to accommodate any mis-alignment of the mask fixing points with the nominal position of the respective rollers.

More preferably, the one of the image sheet and the mask sheet which is operatively associated with the drive rollers is tensioned by providing at least one pair, preferably two pairs, of tension springs, the, or each, pair of tension springs operating by tensioning the mask sheet, or image sheet, diagonally in opposing directions.

It is preferred to additionally tension the mask sheet, or image sheet, by providing at least two more links attached to or integral with the mask sheet or image sheet. Each link is operatively associated with opposing edges of the image sheet or mask sheet and each link runs over and behind a free-running roller axially positioned along the longitudinal axis of the relevant drive roller on that edge of the sheet, the links being connected together by tension springs. The links are free to self-centre over the face of the free-running driven rollers by the pull of the diagonally opposing tension springs.

This tensioning means, together with the driven link means, ensures constant contact between the mask sheet and the image sheet over the entire face of the mask and image sheets without distortion. The selection of the number of driven links is usually proportional to the width of the illuminated display device of the present invention. The driven links are ideally positioned laterally, on each side, of the drive rollers.

Advantageously, the image sheet and the mask sheet are supported on a platen and the platen is curved so as to provide constant contact between the image sheet and the mask sheet. The contact over the platen is maintained by the tensioning means and driven link means hereinabove described. The height of the curvature of the platen is chosen so as to provide constant contact but with minimal friction as one of the mask sheet, or image sheet, oscillates over the other of the mask sheet, or image sheet. The curvature at a second platen axis, being defined as the axis at right angles to the longitudinal axis of the first and second drive roller means, has the height of curvature between 1.5% and 5%, preferably 2.5%, of the length of the platen in the second axis.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which :-

Figure 1 is a perspective partial front view of an illuminated display device according to a first embodiment of the present invention;

Figure 2 is a rear view of the ^' illuminated display device of Figure 1;

Figures 3, 3a, 4 and 4a are enlarged views of the cam and cam follower support plate of Figure 2, showing, in sequence, anti-clockwise movement of the cam;

Figure 5 is an enlarged partial view of the rear view of Figure 2, showing the links, crank levers and drive rollers;

Figure 6 is a perspective partial front view of an illuminated display device according to a second embodiment of the present invention;

Figure 7 is a rear view of the illuminated display device of Figure 6;

Figure 8 is a partial rear view of Figure 6, showing the mechanism linking one pair of drive rollers to the cam follower support plate; Figure 9 is a perspective rear view of an illuminated display device according to a third embodiment of the present invention;

Figure 10 is a rear view of the cam mechanism of the illuminated display device of Figure 9;

Figure 11 is a partial rear view of Figure 9 showing the mechanism linking the pairs of drive rollers to the cam follower support plate;

Figure 12 is a perspective rear view of an illuminated display device according to a fourth embodiment of the present invention; and

Figure 13 is a rear view of the cam mechanism of the illuminated display device of Figure 12.

Referring now to Figures 1-5 of the accompanying drawings, there is illustrated an illuminated display device according to a first embodiment of the invention, generally indicated as 10. In the first embodiment 10, the image strips on an image sheet 14 and the opaque and transparent strips on a mask sheet

16 are arranged in a substantially vertical orientation and a moving means 44 is arranged to impart substantially horizontal oscillating movement to the mask sheet 16. It will, of course, be appreciated that the image portions on the image sheet 14 and the opaque and transparent strips on the mask sheet 16 may be in a substantially horizontal orientation and, in that event, the moving means 44 is arranged to impart substantially vertical oscillating movement to the mask sheet 16.

Figure 1 illustrates a partial front view of an illuminated display device according to the first embodiment of the invention. In Figure 1, there is visible an outwardly convex platen 12. The platen 12 is usually opaque and, as such, may be formed from a plastics, for example, Perspex or Lexan (Trade Mark) or a glass-type material. Alternatively, the platen 12 may be substantially transparent and, in that event, a diffuser effect is created by the printing method chosen for an image sheet 14. Specifically, the series of strip images may be photographed onto a diffuser support material.

The curvature of the platen 12 along a first axis 36, being substantially at right angles to the longitudinal axes of a pair of first and second drive rollers 22, 24 to be described, is chosen at minimum radius to reduce friction between the image sheet 14 and a mask sheet 16 to maintain the desired overall touching contact between the image sheet 14 and the mask sheet 16 and, thereby, achieving optimum clarity of the displayed image.

The curvature of the platen 12 along a second axis 35, being substantially parallel to the longitudinal axes of the drive rollers 22, 24, is selected to provide sufficient tension between the image sheet 14 and the mask sheet 16, so as to display the image without distortion but with minimal friction between the image sheet 14 and the mask sheet 16. The transverse curvature should be a constant curve so that substantially constant contact is maintained between the image sheet 14 and the mask sheet 16.

The image sheet 14 is located, in use, on the platen 12 and is fixed in position on the platen 12 by any suitable means (not shown) . In addition, the position of the image sheet 14 may be adjusted relative to the first and second margins 18, 20 of the platen 12, again by conventional moving means (not shown) .

The mask sheet 16 is located, in use, on top of the image sheet 14. A pair of drive rollers 22, 24 respectively are each rotatably mounted on a shaft (not shown) at a respective vertical edge 18, 20 of the platen 12. The rotational axes of the rollers are substantially parallel to one another and to the edges of the platen 12.

The opposite edges of the mask sheet 16 are secured to the rollers 22, 24 respectively by a C-shaped sleeve member 30 and a screw 31 arrangement which clamps edge extensions 28, 28' of the mask sheet 16 to the circumference of the rollers 22, 24. This imparts oscillating movement to the mask sheet 16 without angular distortion of the mask sheet 16. The mask sheet 16, therefore, becomes an integral part of a moving means to be described hereinafter.

Tensioning means, generally indicated as 32, in the form of two pairs of equal and diagonally opposing tension springs 34, maintain the mask sheet 16 in touching contact with the image sheet 14. It is important that the action of each tension spring 34 is balanced by an opposing tension spring 34. Thus, the positioning of the tension springs 34 must be symmetrical about both a longitudinal mid-line 35 of the platen 12 and about a transverse mid-line 36 of the platen 12.

When- the drive rollers 22, 24, under the influence of a moving means to be described hereinafter, oscillate the mask sheet 16, the tension springs 34 compensate for

(or dampen) the oscillating movement, whilst retaining tension and overall contact with the image sheet 14.

The present embodiment also includes two pairs of free- running rollers 38, 40 which, like the rollers 22, 24, are each rotatably mounted on a shaft (not shown) at a respective vertical edge 18, 20 of the platen 12 and have rotational axes substantially parallel to one another and to the edges of the platen 12. Extensions 42, 42^' of the mask sheet 16 are attached to the rollers 38, 40 in a similar manner to the attachment of the extensions 28, 28' to the rollers 22, 24. The rollers 38, 40 are pivotably connected to driven links 80, 82, the driven links 80, 82 being connected by a tension spring 83. The springs 83 maintain tension across the mask sheet 16 while the rollers 38, 40 allow the mask sheet to oscillate relative to the platen 12. Each roller 38, 40 is free to move axially of its shaft to a limited extent to accommodate any mis-alignment of the extensions 42, 42¹ with the nominal position of the rollers 38, 40 which might result in distortion of the mask sheet 16. Alternatively, each extension 42, 42¹ may be connected by a spring 83 to a pillar extending from the underneath framework (not shown) of the device 10. Such an arrangement would likewise help prevent any mis-alignment of the extensions 42, 42'.

With particular reference to Figures 2-4 of the accompanying drawings, the illuminated display device 10 of the present embodiment includes a moving means generally indicated as 44. The moving means 44 includes a drive motor (not shown) mounted on a support frame 46, the drive motor having a drive motor shaft 48 extending therefrom. A rotary cam 50 is mounted on the drive motor shaft 48. A cam follower support plate 52 is pivotally mounted at pivot point 54 to the support frame 46. The plate 52 is provided with an arcuate slot (not shown) through which the shaft 48 passes and positioned to allow movement of the plate 52 relative to the drive motor shaft 48. Two opposing cam follower levers 58, 60 are pivotably mounted at 58^', 60^' respectively on the plate 52. It will be appreciated that the opposed dispositions of the cam followers 58, 60 ensures that oscillating movement of the cam follower 58 is equal and opposite to that of the cam follower 60.

It will also be appreciated that the cam 50 may be a fixed velocity cam or a constant rise and quick return cam, depending on the storyline to be displayed or the animation image exposure. Thus, the display can be a variable time image effect, a static display or a display in animation mode.

Figures 3, 3a, 4 and 4a of the accompanying drawings further illustrate the moving means generally indicated as 44. The cam followers 58, 60 are pivotably mounted on the plate 52 at respective pivot points 58 ' , 60 ' and their free ends are urged towards each other by a tension spring 62 extending between the free ends. On the plate 52 there are respective fixed drive bosses 64, 66. The drive bosses 64, 66 are spaced-apart by a distance very slightly greater than the maximum dimension (lift) of the cam 50. Adjustable stops 68, 70 on the support frame 46 define the limits of oscillation of the plate 52.

In use, as the cam 50 rotates in, for example, an anticlockwise direction starting from the position seen in Figure 3, the cam 50 urges the cam follower 58 away from the drive boss 64, whilst simultaneously, under the influence of the spring 62, urging the other cam follower 68 towards, and into contact with, the other drive boss 66. Further rotation of the cam 50 will then, through the action of the spring 62 pulling on the cam follower 60 now abutting the drive boss 66, cause pivoting of the plate 52 in an anticlockwise direction until it comes to abut against the stop 68, Figure 3a.

Further rotation of the cam 50 to its maximum lift, Figure 4, is permitted by further extension of the spring 62. Once the cam 50 has rotated beyond the point of maximum lift, Figure 4a, the cam spring 62 starts to contract, the plate 52 eventually moves away from the stop 68, and the equivalent process then reoccurs on the opposite side of the plate 52, i.e. the cam 50 urges the cam follower 60 away from the boss 66 which pulls the cam follower 58 into engagement with the boss 64, this in turn rotating the plate 52 clockwise against the stop 70 where it stays until the cam passes its position of maximum lift.

Thus continuous rotation of the cam 50 is converted to oscillatory pivoting of the plate 52. This in turn imparts longitudinal oscillating movement to the links 72, 74 which are pivoted at their inner ends to opposite edges of the plate 52 and coupled at their outer ends to the drive rollers 24, 22 respectively, in a manner to be described.

It will be appreciated that this moving means 44 permits, by adjustment of the stops 68, 70, the amplitude of the oscillations produced by the cam 50 to be accurately adjusted and, therefore, overcomes any irregularities in the dimensions of the cam 50 itself.

A respective crank lever 76 extends radially from a screw-threaded aperture (not shown) in each drive roller 22, 24. The free end of each crank lever 76 is connected by a respective one of the links 72, 74 to the cam lever 52. Thus, longitudinal oscillatory movement of the links 72, 74 is translated into an oscillatory rotation of each roller 22, 24, leading in turn to the mask sheet 16 being moved back and forth across the image sheet 14. A screw 78 on each crank lever 76 permits adjustment of the distance between the axis 25 of each roller 22, 24 and the point of connection of the respective link 72, 74. Thus, a mechanical advantage is achieved. The mechanical advantage adds to the smoothness of movement of the mask sheet 16. The mechanical advantage is adjustable by moving each link 72, 74 towards, or away from, the axis 25 of each drive roller 22, 24. This adjustment alters the length of movement of the mask sheet 16 and ensures a clear image at the top and at the bottom (change-over points) of the rotating cam 50. It is envisaged that this adjustment will, usually, be factory-set although a skilled operator would be provided with instructions for its adjustment.

A tension spring 73 is interposed within one of the links 72, 74 to impart the appropriate tension to the mask sheet 16. The tension of the link spring 73 is selected to provide the correct level of tension, and contact with, the image sheet 14 without undue friction being applied between the image sheet 14 and the mask sheet 16, whilst also having sufficient tension so as to move the mask sheet 16 through the links 72, 74, as if it were a solid coupling.

The motor (not shown) may be, for example, a microgear motor with a rotational speed selected for the desired image display time. The extent of movement of the mask sheet 16 is controlled by the pitch dimension (cam lift) of the cam 50 and the mechanical advantage of the crank levers 76, which reduces torque and noise output of the motor (not shown) . As the distance between the free end of each crank lever 76 and the respective axis 25 of the drive rollers 22, 24 is reduced, by partially unscrewing the respective crank lever 76 relative to its drive roller 22, 24, the crank lever's mechanical advantage or leverage distance ("throw") is reduced which, in turn, reduces the extent of oscillation of the mask sheet 16.

The illuminated display device 10 of the present embodiment is used in the following manner. The desired image sheet 14 is located on the platen 12 using conventional fixing means (not shown) . The mask sheet 16 is then located over the image sheet 14 with its extensions 28, 28' releasably connected between the respective substantially C-shaped sleeves 30 and opposing drive rollers 22, 24. Extensions 42¹, 42- of the mask sheet 16 are also releasably connected between opposing driven rollers 38, 40. Specifically, extensions 42', 42 pass through 180 degrees of the free-running rollers 38, 40 and are each pivotably connected to respective driven links 80, 82. The driven links 80, 82 are then releasably connected to each other by the tension spring 83. The tensioning means 32 is then engaged. The mask sheet 16 is aligned with the image sheet 14, by moving the image sheet 14, in conventional manner (not shown) , so as to align one series of image portions through the transparent strips (not shown) of the mask sheet 16. When the image sheet 14 and the mask sheet 16 are so aligned, the image sheet 14 is fixed in place. As the mask sheet 16 oscillates under the influence of the moving means 44, extensions 42, 42' are free to self-centre under the influence of the diagonally arranged tensioning means 32. This oscillating movement of the mask sheet 16 permits sequential display of a series of images from the image sheet 14. Referring now to Figures 6-8 of the accompanying drawings, there is illustrated an illuminated display device according to a second embodiment of the invention, generally indicated as 110. In Figures 6-8 components equivalent to those in Figures 1-5 have been given the same reference numerals plus 100.

In the second embodiment, the illuminated display device 110 comprises two pairs of drive rollers 122, 124, as well as two pairs of free-running rollers 138, 140. Other than inter-linking of the two pairs of drive rollers 122, 124 to the cam follower support plate 152 to be described hereinafter, assembly and operation of the second embodiment 110 is similar to that described hereinabove for the first embodiment 10.

Figure 7 illustrates how the two pairs of drive rollers 122, 124 are linked. Specifically, drive links 86, 88 are pivotably connected at 90 to the cam follower support plate 152 and, at their free ends, are axially connected, via slots 92, to the underneath of the platen 112. The drive links 86, 88 are each pivotally connected at approximately their mid-point to respective links 172, thereby imparting, by a pulling/pulling motion, oscillating movement to the pair of drive roller means 122, 124 in synchronism.

In the embodiment of Figs. 6 to 8 each free-running roller 138 and 140, and each roller 122 and 124 of one of the pairs of driven rollers, is free to move axially of its shaft to a limited extent to accommodate any mis-alignment of the extensions 128, 128', 142 and 142¹ with the nominal position of the respective rollers. Figures 9-11 of the accompanying drawings illustrate an illuminated display device according to a third embodiment of the invention. In Figures 9-11 components equivalent to those in Figures 1-5 have been given the same reference numerals plus 200.

The third embodiment has two pairs of drive rollers 222, 224 but no driven free-running rollers equivalent to the rollers 38, 40 in the first embodiment. Other than the inter-linking of the two pairs of drive rollers 222, 224 to the cam follower support plate 252 to be described hereinafter, assembly and operation of the third embodiment is similar to that described hereinabove for the first and second embodiments.

In the third embodiment the inner ends of two crank levers 94 are pivoted at pivot points 96 to the plate 252 and their outer ends are pivoted at pivot points 98 to the links 272. Intermediate their length each crank lever 94 is pivoted at pivot point 100 to the supporting framework (not shown) . Thus, pivotal oscillation of the plate 252 will cause oscillatory rotation of each crank lever 94 about its pivot point 98, as indicated by the double headed arrows in Figure 11. This in turn imparts longitudinal oscillating movement to the links 272, 274 to drive the rollers 222, 224 as previously described.

In the embodiment of Figs. 9 to 11 each roller 222 and 224 of one of the pairs of driven rollers is free to move axially of its shaft to a limited extent to accommodate any mis-alignment of the mask sheet edge extensions with the nominal position of the respective rollers .

Figures 12 and 13 of the accompanying drawings illustrate an illuminated display device according to a fourth embodiment of the invention. In Figures 12 and 13 components equivalent to those in Figures 1-5 have been given the same reference numerals plus 300.

Like the third embodiment, the fourth embodiment has two pairs of drive rollers 322, 324 but no driven free- running rollers. Other than the inter-linking of the two pairs of drive rollers 322, 324 to the cam follower support plate 352 to be described hereinafter, assembly and operation of the fourth embodiment is similar to that described hereinabove for the previous embodiments .

In the fourth embodiment the inner ends of two crank levers 94' are pivoted at 96' to the ends of two further links 102 respectively. These latter extend off to the side of the device where they are coupled in common to the cam follower support plate 352 by a short link 106, the link 106 being pivoted in common to the links 102 at pivot point 107 and pivoted to the plate 352 at pivot point 108. A further, relatively long link 104 is pivoted at one end to the common pivot point 107 and at its other end to a pivot point 105 fixed relative to the frame of the device. The plate 352 is also pivoted at fixed pivot point 354 to the frame. Finally, the outer ends of the crank levers 94' are pivoted at pivot points 98' to the links 372 and each crank lever 94 ' is pivoted intermediate its length at pivot point 100' to the device frame.

In operation, as the plate 352 oscillates under the action of the rotating cam 350 the pivot point 107 oscillates back and forth along the large radius arc centred on the pivot point 105, as indicated by the double-headed arrow in Figure 13. This ensures that the motion of the pivot point 107 is to all intents and purposes a straight line perpendicular to the axes of the rollers 322, 324. The motion of the pivot point 107 acts via the links 102 to rotate the crank levers 94' back and forth about their pivot points 100', which in turn imparts a longitudinal oscillatory motion to the links 372, 374 to drive the rollers 322, 324 as previously described.

In the embodiment of Figs. 12 and 13 each roller 322 and 324 of one of the pairs of driven rollers is free to move axially of its shaft to a limited extent to accommodate any mis-alignment of the mask sheet edge extensions with the nominal position of the respective rollers .

It will be noted that in the embodiment of Figs. 12 and 13 the linkage mechanism has allowed the motor and cam mechanism to be moved laterally beyond the periphery of the image sheet. This is especially advantageous in the case of large area displays which need large motors which cannot be conveniently positioned within the periphery of the image sheet. Large motors also generate considerable heat, and the lateral location of the motor removes this source of heat from near to the image sheet .

Illuminated display devices of the present invention may be constructed in three sections: a substantially rigid rear housing, which may contain a light source (if back-illuminated) for installation, for example, on a display stand or, more usually, on a wall; a front housing having a protective screen cover which optionally has a non-reflecting surface and which can also contain a light source (if front-illuminated) ; and a centre section comprising the image sheet, the mask sheet or grid having at least one series of transparent windows alternating with a series of opaque strips (opaque in this context means substantially non- transparent) , and the drive means to move the image sheet and the mask sheet in relation to one another. The centre section can, if desired, contain a light source for back-illumination or side-illumination.

It will be appreciated that, as a consequence of the substantially parallel configuration of the pair(s) of drive rollers relative to the image sheet and the mask sheet, many advantages ensue. Specifically, this permits wide variations in the dimensions of the image sheet and the mask sheet, for example, within the range of A2, Al, A0 and 6 sheet, all in portrait format, as well as, "banner" in landscape format. It will, of course, be appreciated that illuminated display devices according to the present invention can be supplied in either portrait or landscape formats. Table I shows transverse and longitudinal dimensions of such sheets, although it will be appreciated that, when used in landscape format, the transverse and longitudinal dimensions are transposed. Equally, the illuminated display device of the present invention can be used to display intermediate sizes or larger sizes, depending on the desired end application. In addition, the illuminated display device of the present invention can accommodate additional combination dimensions, for example, a width corresponding to A0 of 840mm and the height corresponding to A4 of 235mm.

A further advantage of the illuminated display device of the present invention is that it enables the Al and A0 size units to be supplied with image sheets and corresponding mask sheets in either vertical or horizontal formats. This additional versatility can only be achieved because of the tensioning and drive arrangement as hereinabove described.

TABLE I

Portrait

Sheet Identity Transverse Longitudinal

Dimension (mm) Dimension (mm)

A2 420 595

Al 595 840

A0 840 1200

6 sheet 1200 1800 Landscape

Sheet Identity Transverse Longitudinal Dimension (mm) Dimension (mm)

Banner 500 3000

If desired, the provision of further pair(s) of drive rollers at right angles to the first pair of drive roller, with a second driving means operatively associated with the further pair(s), permits the display of a series of images in either portrait or landscape configuration as desired.

Furthermore, the dimensional flexibility of the image sheet and the mask sheet open the way for further opportunities in the arrangement of images on the image sheet - previously only two or three series of image portions in strip form have usually been used on a single image sheet.

Due to the improved driving means, up to five full se'ries of non-animated image portions in strip form can be incorporated on an image sheet for use in an illuminated display device of the present invention. Equally, up to ten full series of animated image portions in strip form can be incorporated on an image sheet of the same dimensional structure, enabling optional display formats on a common mask sheet. In addition, the image sheet can incorporate several images, arranged as image portions in the grid configuration, so that several images are on display at the same time. Thus, up to ten sequential images can be displayed in the grid configuration, each composed as several individual images.

The invention is not limited to the embodiments described herein which may be amended or modified without departing from the scope of the present invention.

Claims

1. An illuminated display device comprising an image sheet including a plurality of series of image strips; a mask sheet having alternate opaque and transparent strips, the mask sheet being located in face-to-face relation to the image sheet; at least one pair of drive rollers having substantially parallel axes attached respectively to opposite edges of one of the image sheet and mask sheet; and means to oscillate the one of the image sheet and mask sheet relative to the other of the image sheet and mask sheet by driving the pair of rollers in synchronism alternately in opposite directions, the driving means comprising a rotary cam, at least one cam follower associated with the cam, a respective crank lever associated with at least one of the drive rollers, and a linkage mechanism connecting the crank lever to the cam follower.

2. A display as claimed in claim 1, wherein the linkage mechanism comprises a pivoted cam follower support member and wherein the cam follower is pivoted to the support member and resiliently biased against the cam, the arrangement being such that rotation of the cam effects oscillation of the cam follower and, via the resilient biasing means, oscillation of the support member, the linkage mechanism further including means coupling the crank lever to the support member.

3. A display as claimed in claim 2, further including stop means defining the limits of oscillation of the support member, the resilient biasing means accommodating any further movement of the cam follower when the support member abuts the stop means.

4. A display as claimed in claim 3, wherein there are two cam followers pivoted to the support member and disposed respectively on opposite sides of the cam, the cam followers being biased towards one another by the said resilient biasing means which comprises a resilient tensioning means extending between them, each cam follower having a respective associated stop means which limits the movement of that cam follower towards the other.

5. A display as claimed in claim 2, 3 or 4, wherein there is a further crank lever associated with the other drive roller and the linkage mechanism further includes means coupling the further crank lever to the support member.

6. A display as claimed in claim 5, wherein the means coupling the further crank lever to the support member includes a resilient tensioning means to maintain tension in the said one of the image sheet and mask sheet.

7. A display as claimed in any preceding claim, comprising two pairs of drive rollers driven in synchronism by the driving means, the rollers of one of said pairs being free to move along its own axis.

8. A display as claimed in any preceding claim, wherein the image sheet is slightly curved and the display further includes two pairs of diagonally opposing tension springs attached respectively to diagonally opposite corners of the mask sheet to maintain the mask sheet in touching contact with the image sheet .

9. A display as claimed in any preceding claim, wherein the rotary cam is driven by a motor which is located laterally beyond the periphery of the image sheet .