GB2111282A - A display device having a rotating reflector - Google Patents

Abstract

A display device comprises a rotatably-mounted sheet 10 of reflective material, the surface of the sheet having one or more patterns of light-reflecting grooves. As the sheet is rotated by a motor, the grooves enhance the reflection of light in certain directions. The display device may have coloured light sources A1- D2. <IMAGE>

Description

SPECIFICATION A display device having a rotating reflector The present invention relates to a display device having a reflective sheet of material which is grooved to provide enhanced reflection.

Devices of this type are well known.

According to the present invention there is provided a display device comprising a rotatablymounted sheet of reflective material, a surface of the sheet having one or more patterns of lightreflecting grooves.

Preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings of which: Fig. 1 shows a reflective sheet used in a first embodiment of the present invention: Fig. 2 shows a side view of a casing which is known from the prior art and which includes light sources for illuminating a reflective sheet; Fig. 3 shows the reflective sheet of Fig. 1 in use with a lighting arrangement which is known from the prior art; Fig. 4a shows side and front views of a reflective sheet with a previously proposed lighting arrangement; Fig. 4b shows side views of reflective sheets with two previously proposed lighting arrangements; Fig. 5 illustrates further designs which may be used in embodiments of the present invention;; Fig. 6a shows the components of a display unit comprising a display panel and a rotating reflective sheet; Fig. 6b shows a front view of the displaying unit, with the components of Fig. 6a assembled; Fig. 6c shows a side view of the display unit of Fig. 66.

Fig. 7a shows front and side views of a further display unit comprising a display panel behind which is mounted a rotating reflective sheet; Fig. 7b shows a coloured light source for the display unit of Fig. 7a; and Fig. 7c shows part of an alternative coloured light source for the display unit of Fig. 7a.

Before describing preferred embodiments of the present invention in detail, it will be of use to summarize the prior art. During the 1 930s a Frenchman, Louis Dufay, was granted patents in various countries, including the U.K. These patents described how metallic foil could be embossed in such a way that the grooves thus embedded in the foil at a pre-determined alignment to each other, would reflect light. The light so reflected would produce various patterns and effects. The grooves embossed in the foil can be so fine as to be invisible except when under magnification. Ideally, this metallic foil has a wax bed and paper backing.

The methods of embossing by hand and consequent reproduction are set out in the original patents; see G.B. patents 325576, and 486906, French Patent 821,804 and U.S.

patents 1996539, and 2313489.

This "Dufay work" is in production to this day and is used mainly for Xmas and greeting cards, calendars, shelf-strips, brochure covers etc. where the embossed foil relies on ambient light to given an "enhanced" effect to coloured pictures and advertising material. It is also sold as abstract and pictorial art, often without additional colour. The illustration in Figure 1 could well be sold as a piece of embossed art, perhaps for framing.

A new perspective was given to the "Dufay work" around 1950 when a patent was granted to another Frenchman, Pierre Latrobe. This patent states that if 4 lamps, arranged in a circle at 900 intervals from each other, were to rotate simultaneously around, and at a given distance from an embossed foil picture, then those lamps would 'animate' the designs embossed into the foil.

The diagrams in Figure 1 is a circle divided into concentric bands, each band aligned 22+0 from its neighbour. The parallel lines represent the previously mentioned grooves which are bedded into the foil. It can be seen that if a source of light was located at A1 (or A2) it would be reflected to the viewers via grooves at right angles to the rays it emitted, viz. Band 1. Thus a light at B, (or B2) would illuminate Band 7, C1 (or C2) Band 5, D1 (or D2) Band 3. In practice of course, a light source would partially illuminate Bands on either side, according to its intensity. If light was solely from say, C, (or C2) then Band 5 would be brightest, followed in diminishing intensity by Bands 4 and 6, 3 and 7, 2 and 8, right down to Band 1 which would be totally dark (without light).

What Latrobe's patent pointed out was that if 4 lamps set at say, A1, C1, A2 and C2 started to rotate simultaneously, they would cause the Bands in Figure 1 to illuminate in succession, thus giving the viewers an 'animated display'. When the lamp at A1 had moved clockwise to position C1 (also C1 toy2, A2toC2, C2toA1) every Band would have been illuminated, these concentric Bands being seen to move out from the centre to the periphery. This continuing rotation of lights would give a continuous 'exploding circle' effect.

With the lights rotating at a constant speed in a given direction it can be seen that any number of movements could be achieved at whatever speed or direction. The process could depict almost any continuous, regular motion and, together with its successor-the 'sequenced light display', it successfully showed many complex, coloured subjects such as motor engines (oil, fuel, water flows, pistons, cogs etc), industrial processes, aircraft flying, cars on roads etc. etc.

This rotary light system could also introduce moving colour to silver embossed foil by, for example, having on Figure 1, a red lamp at Ar, blue at C1, green at A2 and yellow at C2. As these lamps rotate it would be seen that not only were the Bands moving from the centre, but that they were changing colour as well.

In order to produce a finished display it was necessary to position the lamps 11 in 'cabinet' 19 in such a way that the light from the lamps was able to reach all the embossed grooves on the picture. It was also necessary to hide the lamps from the viewer as they would be an irritating distraction. Figure 2 depicts a simplified side or top section of such a display and shows how an onlooker at '0' would have his view of the picture 'partially obscured by the 'cabinet'. The 200 angle shown in Figure 2 was about the minimum angle at which light from a lamp 11 would reach the centre of the picture. The 1000--1050 angle allowed the lamps to be outside the perimeter of the picture in order to avoid unwanted lamp reflections on the picture surface.

During the early 1960's the Rotary Light system was superseded by another patented device-the Sequenced Light system.

In this case a number of lamps, usually 24, were equi-spaced around the picture. A mercury switching device switched the lamps on and off in a pre-arranged sequence in such a way that the effect of rotary lighting was simulated.

These patents were initiated by Frenchman M.C.K. de Poray (see French Patents 1311171, addition 83211, and 1427777) and an Englishman David H. Young, (see G.B. Patent 940588).

Figure 3 shows how these lights would be arranged around the foil shown in Figure 1. The lights were sequenced basically as follow:- Lights A12 3 4 would come on simultaneously and then go off, followed by B1234, C,,,, etc. etc.

Eventually the picture shape changed from a circle or square or rectangular format around which shapes the lamps were spaced. They are now switched electronically. The pros and cons of sequenced light displays are discussed in the article "A Dynamic Technique in Visual Communication" by David Young in the May 1 981 edition of "Point of Sale and Screen Printing". Although the method of light transmission changed, the geometry shown in Figure 2 did not. The lamps still had to be set at a certain distance from the picture and still had to be encased.

Both Rotary Light and Sequenced Light systems relied entirely on their lamps to produce an 'animated display'. To this extent it could be said that their ideal conditions for viewing would be in a darkened room or at night, where there was no strong ambient light.

This in effect was their greatest drawback, because as the ambient light increased in strength the effect of the lamps 'animating' the picture was seen to decrease and the 'animation' effect weakened accordingly.

Any more powerful source of natural or arti ficial light shining on to the embossed foil surface of the picture would cause the embossed grooves that reflected such light to be rendered 'immobile' or 'inanimate'.

As the movements depicted by these displays were continuous and regular, the effect of competing light would interrupt those movements and they would cease to be authentic.

Another further drawback was encountered with the arrangement of Figure 2 whereby a viewer could only obtain a perfect impression of the picture when he was directly in front of the display which would ideally have to be at eye level.

Further minor disadvantages of the system were: (a) Failed lights reducing effectiveness of animation.

(b) Some degree of 'flicker' observed as lights pulsed around.

(c) When wax-backed foil was used and exposed to prolonged sunlight and/or heat from the lamps, it had a tendency to delaminate in places due to the wax melting. This could produce unsightly 'ridges' on the picture.

Over the years various attempts were made to improve upon the 'recessed' picture or 'cabinet' effect of the displays.

They included: a) One-edge lighting display In order to function efficiently, i.e. to guarantee that all embossed grooves would receive light, it was necessary for the rotary and sequenced light displays to have lighting all around the picture.

The one-edge display shown in Figure 4(a) had just one row of lamps 11. It achieved the aim of needing no cabinet, but at the expense of using too few lamps. Consequently the 'animation' only worked spasmodically as many embossed grooves received no light to animate them. The effect of sunlight or stronger ambient light was more detrimental than usual as it had less light power to overcome and virtually reduced the animation to a standstill.

A variation of this theme entailed replacing the lamps with a tubelight and rotating a helix about it, with more or less the same lack of effectiveness.

b) Attempts were made to utilize the refractive index of PERSPEX (Registered Trade Mark) and certain clear liquids to direct light to the picture Figure 4(b) illustrates the principles employed.

Had they been successful they would still have had to contend with the ambient light problem.

The left hand part of Figure 4(b) shows a block of perspex 21 lit on one side only. The right hand part of Figure 4(b) shows a clear fluid 23 in a PERSPEX tank 22, lit on all four sides.

In the animation systems already described there are three fundamental constituents: a) The embossed foil picture Although this picture depicted "motion" or "animation" it was, in itself, a static entity, being secured at the back of a 'cabinet'.

b) The lamps These lamps were rotated or sequenced around the embossed foil picture in order to produce the desired 'animated' effect. They had to be placed at a distance in front of the picture and beyond its periphery. These lamps has to be hidden from view and were, together with the picture, housed in a 'cabinet', which produced a 'recessed' picture effect.

c) Ambient light Any sunlight, daylight or strong artificial light falling on to the face of the embossed foil picture proved to be detrimental to the functioning of the display. As this ambient light was always 'static' by nature, it rendered motionless those embossed grooves which reflected its light.

In my invention: a) The embossed foil picture is made to rotate (referred to as a ROTAFOIL) b) The lamps There will be no need for either rotary or sequenced light and, therefore, no need for a cabinet, although lamps may be used if desired.

c) Ambient light This may be the sole source of light used to illuminate the embossed grooves in the revolving ROTAFOIL, thus enabling the viewer to see the desired visual effect.

The rotafoil is a piece of metallic foil with a substrate such as Wax, backed by paper or card.

To produce an original ROTAFOIL a network of minute grooves is hand embossed into the foil, these grooves being at a pre-determined alignment to each other. When the ROTAFOIL is rotated it causes each groove in turn to reflect whatever light falls upon it whether it be random or contrived light. This sequence of reflections is seen as a continuously moving optical display.

The design in Figure 1 illustrates such a groove alignment whereby the parallel lines represent the embossed grooves, which, in reality can be so fine as to be visible only under magnification.

The methods of hand-embossing and consequent reproduction are laid down in the original Dufay/Latrobe patents.

The ROTAFOIL can be any desired shape, but the ideal would be a circle whereby, with certain concentric designs, it would not be obvious that rotation was occurring. It could be made to rotate at a desired speed in any direction by whatever means are considered appropriate, such as a small electric motor.

The way in which ROTAFOIL works can be seen by referring to Figure 1: If A1 represents a source of light then all embossed grooves at right angles to it will reflect the light of A1 to the viewer (there is an overlap of reflected light in practice). As it stands Band 1 would receive illumination if the ROTAFOIL 10 is rotated anti-clockwise it will be seen that Bands 8,7,6,5,4,3,2, and 1 again will reflect light in succession as the ROTAFOIL turns and the grooves align themselves to the light source at A1.

It would be observed that the Bands were 'exploding' from the centre outwards. The reverse would be true if the ROTAFOIL was rotated clockwise, i.e. the Bands would be seen to 'implode'. With concentric movements such as this it would not be apparent to the viewers that the ROTAFOIL was actually rotating.

Figure 5 depicts a few of the different designs which could be used. If this particular embossed foil was placed in a sequence light display all the grooves represented on the foil would 'animate' but the actual shapes (squares, circles, triangles) would remain where they were as the picture would be static (secured). If this foil were removed from the sequenced light display and rotated in ambient light, not only would all the grooves 'animate', but the shapes would be seen to move around as well, thereby adding an extra dimension of movement.

Two further examples of movements that could be achieved with a rotating ROTAFOIL and which would not be possible with the sequenced light system or rotary light system are: The disc in Figure 1 could have a small circle 'A' from Figure 5 embossed into its design anywhere outside its centre. As rotation took place it would be seen that the concentric Bands were issuing forth from centre to circumference.

Whilst at the same time, the small circle 'A' would be seen to rotate around, or orbit, the centre of the larger disc. This small circle 'A' would have movement within itself possibly, exploding, imploding or rotating etc.

It would be difficult for the viewers to perceive that the large and small circles were on the same plane, as he would be unlikely to realise that the larger disc was rotating. A similar effect could be achieved by simply printing a small circle in transparent colour through which the concentric Bands were seen to pass. The combination of concentric movement and orbiting colour could again mystify the viewers.

If the embossed grooves on the ROTAFOIL were aligned to each other in a way similar to a gramophone record (all embossed grooves parallel to the circumference and concentric) it would be seen that rotation of such a design produced no 'movement' at all. All that a viewer would see would be a static 'highlight' produced by the reflection of the light source. If small shapes or colours were introduced as in the preceding paragraph it would appear that only these were rotating about an axis through a static background.

Sources of light Any form of light falling upon the face of a rotating ROTAFOIL will be reflected via the embossed grooves. As well as sunlight, daylight and ambient light the ROTAFOIL will reflect any white and/or coloured light falling upon its face.

Coloured lights will be reflected best if the ROTAFOIL is silver. A rotating silver ROTAFOIL will also reflect the colours of objects around it. If it were placed on a red cloth, for example, the red would be reflected via the grooves.

There would not be a conflict of light as found in previous systems. If, for example, a ROTAFOIL had a lamp beamed on to its face during a 24 hour period, the light from that lamp would be fully reflected during the night. As daylight approached the light from the lamp would be gradually overpowered by natural light and would be seen to have its light reflected again as darkness approached. At no time would the ROTAFOIL'S visual effect cease to function efficiently due to light conflict, as one source of light would supersede another.

Moving colours There are three methods whereby colour can be introduced to the ROTAFOIL using the disc in Figure 1 as an example: Printing on to the ROTAFOIL If, in Figure 1, points A1 and A2 were joined, similarly points C1 and C2, it would produce 4 quadrants. If each quadrant were printed a different transparent colour these colours would be seen to rotate and an effect similar to that described previously would occur. It can be seen that there are many combinations of colour, rotation and animation using this method.

Printing on to the transparent advertising panel If the Advertising Panel 12 in Figure 6 had the same 4 colours printed on to its transparent centre and the disc in Figure 1 placed behind it, the exploding Bands would be seen to pass through the colours which would remain static. In this case, of course the ROTAFOIL would be silver.

These two methods could be called rotating colours and static colours and would function under any light conditions. The third method does not involve printed colours at all, but the production of colours by a projector of coloured light Colour light projector (referred to as a CLP) If, in Figure 1, the points A1, C1, A2 and C2 represented different coloured lights the rotation of the ROTAFOIL would show not only the Bands moving in or out, but the colours moving with them.

Effective results could be achieved by directing coloured lamps or lamps with coloured filters on to the ROTAFOIL, but a specifically located projector of coloured light would be much more effective and versatile.

Ideally, the ROTAFOIL 10 would be silver in those areas where coloured light is to be reflected, as this reflects pure colour in the same way that a mirror would. The display unit of Figure 6 has a support stand 18 and a motor 17 for rotating the ROTAFOIL sheet 1 0. A further possible display set-up is shown in Figures 7(a) and 7(b). The source of light 14 could be tubular, or a series of lamps, and should be at least as long as the width or diameter of the ROTAFOIL.

The light emitted by source 14 would be made to pass through a piece of transparent material such as plastic, on to which have been printed the desired transparent colours. The light would project these colours on to the turning ROTAFOIL and they would be seen to 'move' with the 'animation'.

The ideal location for light source 14 would be such that its light reached the top and bottom of the ROTAFOIL 10 and it would be best located near the base of the ROTAFOIL throwing its light upwards. This would also help to hide the coloured light from the viewer.

The colours on the transparent plastic filter can be achieved in various ways, but the use of printing inks would make available a great range of tints and hues.

Referring to the conflict of light mentioned previously the same principle would apply to a CLP. The colours projected on to the ROTAFOIL would vary from pale to intense depending on the strength of the ambient light, but there would be no loss of 'animation'.

A further sophistication of the CLP would be moving, and changing, colours. This could be achieved by having different transparent colours on a transparent tube 1 6 as in Figure 7(C). This filter tube would be hollow and would be made to rotate around the tubular light 1 5. As the ROTAFOIL turned, so the colour tube would rotate around the light tube. The movements on the ROTAFOIL could be seen to be red and yellow, making way for orange and green, then blue and violet, returning to red and yellow etc. etc.

A comparison can be drawn between the CLP shown in Figure 7(a) and the One-Edge lighting display in Figure 4(a):- If the disc in Figure 1 was secured and made the subject of the One-Edge sequenced light system, it can be seen that certain Bands would illuminate over and over again and others would remain 'static', because they were unable to reflect light. In this case Bands 8, 1 and 2 would animate, Bands 3 and 7 might be partially illuminated, but Bands 4, 5 and 6 would be immobile as it would require lights at the side (or 90" removed) to animate them.

When however, the ROTAFOIL rotates and has a static light source such as a CLP the act of rotation causes all the Bands to reflect its light in succession as they are brought into positions where they are able to reflect the light source to the viewer.

Compared to previous animation systems the ROTAFOIL would have certain advantages such as: (a) No ambient light competition to render animation 'immobile' (b) No need for a cabinet, which could obstruct onlooker's view.

(c) No need to be placed at eye-level for best results.

(d) Would not have 'flicker' of pulsating lights on picture edges.

(e) Would not suffer from jerky 'animation' due to sequenced lighting jumping from lamp to lamp.

Due to constant rotation the movements portrayed by the ROTAFOIL would always be very smooth.

(f) Would greatly reduce the risk of Wax delamination as the rotation of the ROTAFOIL would create a surface air current and help to keep the foil cool.

The ROTAFOIL can be used in locations wherever an attractive animated display is required and where the attention of the passer-by can be gained. Examples are windows and counter displays; in hotels, restaurants, discotheques and as a colour changing display to be used with music.

The ROTAFOIL is readily mass produced and is interchangeable and cheaper to run than an average household lamp.

Whereas a sequenced light display is able to portray wide range of subjects suitably for 'animation', such a display will be seen to function efficiently only when it is located away from a competitive light source such as sunlight, daylight and stronger artificial light. Ideally it also needs to be at the eye-level of a viewer and directly in front of him.

The ROTAFOIL's particularly advantageous application is in the field of specialised abstract and geometric patterns and designs producing predetermined visual effects when the ROTAFOIL is rotating. It will also bring into being many animated effects which can only be achieved by employing rotation.

A ROTAFOIL will be seen to function efficiently whenever light of any kind falls upon its rotating face. Its visual effect will then be transmitted to the viewer via its embossed grooves reflecting the light falling upon it.

Its reflection will be most powerful when direct sunlight falls upon it. It will, in fact, reflect all the variations of ambient light around it (i.e. in front of it). Needing no 'cabinet' it can be located almost anywhere and be seen to function efficiently from many angles not previously accessible to rotary and sequenced light displays.

Figures 6 and 7 depict possible ROTAFOIL displays incorporating an advertising panel which could be a rigid, transparent plastic sheet. The shaded area could be printed in opaque colours with advertisers message, logo or product etc.

The transparent centre could be any shape and if desired could be printed with transparent colours.

It is envisaged that the grooves may be relatively wide with narrow ridges therebetween; thus in Figure 1, for example the parallel lines could represent the ridges.

Claims (16)

Claims 1. A display device comprising a rotatablymounted sheet of reflective material, a surface of the sheet having one or more patterns of lightreflecting grooves. 2. A device according to claim 1, which comprises a light source for illuminating the sheet. 3. A device according to claim 1 or 2, wherein the sheet is coloured. 4. A device according to claim 2, wherein the light source is coloured. 5. A device according to claim 2, wherein the light source is surrounded by a rotatable coloured filter element. 6. A device according to any preceding claim, wherein the sheet is substantially circular and a plurality of similarly-shaped grooved regions are equally-spaced around the surface of the sheet. 7. A device according to any of claims 1 to 5, wherein the surface of the sheet has a plurality of concentric circular regions, each region having a plurality of parallel grooves the direction of which changes from region to region. 8. A device according to claim 7, wherein a circular grooved region is superimposed upon at least some of said circular regions. 9. A device according to any preceding claim which comprises a motor for rotating the sheet. 1 0. A device according to any preceding claim, wherein the sheet comprises a metallic foil with a wax substrate backed by paper or card. 11. A display device substantially as herein described with reference to each of the accompanying drawings. New claims or amendments to claims filed on 10 Aug 82 Superseded claims 1-11 New or amended claims:

1. A display device comprising a rotatablymounted sheet of reflective material, the sheet comprising a metallic foil with a substrate of soft material and a surface of the sheet having one or more patterns'of light-reflecting minute grooves.

2. A device according to claim 1 comprising a plurality of regions each having a plurality of parallel grooves, the grooves in adjacent regions being relatively inclined at an angle of 450 or less.

3. A device according to claim 1 or 2, wherein the surface of the sheet has a plurality of concentric annular regions, each region having a plurality of parallel grooves the direction of which changes from region to region.

4. A device according to claim 3 wherein the direction changes by an angle substantially equal to 22+0 from one region to another.

5. A device according to claim 3 or 4, wherein a circular grooved region is superimposed upon at least some of said annular regions.

6. A device according to any preceding claim which comprises a light source for illuminating the sheet.

7. A device according to claim 6, wherein the light source is coloured.

8. A device according to claim 6, wherein the light source is surrounded by a rotatable coloured filter element.

9. A device according to any of claims 1 to 6, wherein the sheet is coloured.

10. A device according to any preceding claim, wherein the sheet is substantially circular and a plurality of similarly-shaped grooved regions are equally-spaced around the surface of the sheet.

11. A device according to any preceding claim which comprises a motor for rotating the sheet.

12. A device according to any preceding claim, wherein the substrate is of wax material.

13. A device according to any preceding claim, wherein the substrate is backed by paper or card.

14. A device according to any preceding claim wherein the grooves are visible only under magnification.

15. A display device comprising a rotatablymounted sheet of reflective material substantially as herein described with reference to each of the accompanying drawings.

16. A display panel having a transparent section at least part of which is coloured, a display device according to any one of the preceding claims being mounted behind and viewable through the transparent section.