AU611156B2 - Display with a lamellar grid - Google Patents

Description

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1.4 AU-AI-17206/ 8 8 1111IJIRG ON FUj ff G ?E E~UN PCT _V SA raktic Bi~r INTERNATIONAL AME~3 N VE FFE ~T ?TN DEM VERTRAG OIBER DIE INTERNATIONALE ZUSA EN BEI AUF DEM GJ3BIET DES PATENTWESENS (PCT) (51) Internationale Patentklassifikation 4~ (11) Internationiale Veriientlichungsnummer: WO 88/ 09546 G09F 19/18, G03B 37/02 Al (43) Internationales G04B 19/00 Veriiffentlichungsdatum: 1. Dezember 1988 (01.12.88) (21) Internationales Aktenzeichen.: PCT/CH88/00098 (7)Gemneinsamner Vertreter: BOCHEL, Kurt, Bergstras- (22) Internationales Anmieldedatumn: 24. Mai 1988 (24.05.88) se27FL95 rsn(I) (81) Bestimmungsstaaten: AT (europdisches Patent), AU, (31) Prioritiitsaktenzeichen: [970/87-6 BE (europdisches Patent), CH- (europdisches Patent), DE (Gebrauchsmuster), DEF (europdisches Patent), (32) Prioritiitsdatumn: 21. Mai 1987 (2 1.05.87) FR (europdiisches Patent), GB (europaisches Patent), IT (europfiisches Patent), JP, LU (europbisches Pa- (33) Priorititsland: CH tent), NL (europiiisches Patent), SE (europiiisches Patent), US.

(71) Anmelder (fir alle Bestimmungsstaaten ausser US): TECHNOLIZENZ ByV. [NL/NL]; Breitnerlaan 146, Veriiffentlicht NL-2596 HG Den Haag Mit internationalem Recherchenbericht.

(71)(72) Anmielder and Erfinder: B OC HIE L, Kurt, F. [LI/LI]; A. 0o. i 2 FEB 18 Bergstrasse 297, FL-9495 Triesen (LI).

(72) Erfinder; und Erfinder/Anmelder (r-urftr US) SEC KA, Jan [CS/CA]; AUSTRALIAN 31 High Street E. 203, Mississauga, Ontario L5G 1J9 2~DC18 21DC18 PATENT OFFICE (54)Title: DISPLAY DEVICE WITH A DISPLAY FIELD AND A LAMELLAR GRID, PROCESS FOR PROD-U- CINGT HE LAM ELLAR GRID (54) Bezeichnung: ANZEIGEEINRICHTUNG MIT ELNEMA ANZEIGEFELD UND ELNEM LAMELLENRASTER, SOWIE VERFAHREN ZUR HERSTELLUNG DES LAM ELLEN RASTERS -a (57) Abstract A display has a display field containing information and carrying a lamellar grid for directing light rays or preventing an image from being seen from the side. The display field can rotate in all directions around an axis The lamellar grid is provided with spacer blocks between the lamellas ensuring a high stability of the display device even at light rotational speeds. The spacer blocks may be lamellar bridges or transparent disks.

(57) Zusaininenfassung Die EAindung betrifft eine Anzeigeeinrichtung mit einem eine Information tragenden Anzeigefeld, das einen Lamellenraster zur Orientierung von Lichtstrahilen oder :zur Verhinderung einer seitichen Betrachtungsmdglichkeit eines Bildes trtigt. Das Anzeigefeld ist um eine Achse (14) nach allen Richtungen drehbar. Der Lamellenraster ist erF-indungsgemass mit Abstandhalter zwischen den Lamellen versehen. Dadurch ist eine grosse Stabilitit der Anzeigeeinrichtung auch bei h~heren Umdrehungszahlen gewiihrleistet. Die Abstandhalter ktinnen lamellenartige Stege oder auch transparente Scheiben sein.

u .hel U L a ?±ucLioun co 'recnno±izenz B.V. and Kurt F.

Buchel.

SBR/JS/0191M 1

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880520 1 1282PC Display means having a display field and a lamellar grid, and a process for the production of the lamellar grid The invention relates to a display means according to the precharacterizing clause of Claim 1.

A display means of this type is known from EP-A-208283, which is herewith deemed to be disclosed for the purposes of this description. The lamellar grid separates an optical picture in such a way that the latter can be seen completely from only a limited radiation angle. However, if the picture is viewed from an oblique it is invisible, or appears darkened, to the viewer. In such a case, the viewer sees only the lamellae which are apparently located at gaps. The following rule applies: the smaller the radiation angle and the larger the distance to the viewer, the sharper but also less intense is the picture. The stated EP-A-208283 describes blind-like lamellae, which in practice have not proven sufficiently stable when the rotational speed became larger. Lack of rigidity of the lamellae frequently led to distortion of the picture or to an ill-defined transition from the visibility phase of the picture to its invisibility phase during a complete rotation.

25 It is therefore the object of the invention to design the lamellar grid in such a way that it has sufficient stability in all directions, even at high rotational speeds. Furthermore, any vibrations of the lamellae should be prevented. In addition, the lamellar grid as such should be capable of being p'roduced separately from the remaining components of the display means or capable of being easily mounted.

All these objects are achieved in a satisfactory manner by the features of Claim 1.

Various advantages and further embodiments are

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0k_ SBR/JS/0191M 'i Vf 2 described in the characterizing clause of the subclaims and in the description of the Figures: The invention is illustrated by way of example with reference to the drawing.

Fig. 1 shows a display means on which individual spacers have been mounted; Fig. 2 shows an enlarged representation of the lamellae cast in a block; Fig. 3 shows a plan view of a single cast block having a different surface structure, partially cut away; AO Fig. 4 shows an individual spacer of transparent material; Fig. 5 shows two spacers, partially cut away, and Fig. 6 shows a honeycomb-like grid with metal spacers.

Fig. 7 shows measures applied to a rotating cylinder to improve the optical grid properties, Fig. 8-12 shows different grid variants, Fig. 13-15 show combination arrangements of grids and picture and Fig. 16 and 17 show grids having different optical parameters.

A picture 15 which is illuminated by transmitted light from a light source 16 is located in O 25 a cylinder 13 (Fig. 1 and in a plane through the axis 14 of the cylinder. A grid consisting of lamellae la parallel to the axis 14 is provided between the picture 15 and the light source 16. The lamellae la are kept a distance apart from one another by flat metal spacers 2a. The spacers lie in different planes extending at right angles to the axis 14. The picture can also be mounted directly between the lamellae.

The cylinder 13 is essentially transparent but is provided with a reflective coating on the inside or outside of that side 17 which faces the light source.

p I -0/ 3 The cylinder is rotated by a drive unit (not shown), so that the picture is visible all around. The display field formed by the picture and grid could also be rotated alone (particularly in the case of LCD or electroluminescence displays), but in the case of transmitted light pictures the light source 16 must in any case be darkened on its side which faces away from the picture. However, the invention also embraces a design which combines transmitted light and reflected light. It is also possible for a further cylinder, which is not shown, to serve as a housing, at least as O a dust cover, around the cylinder 13.

Even in the case of high centrifugal forces, the lamellae la cannot move sideways since they are mutually supported by means of the spacers 2a. The sheet-like arrangement of the spacers 2a also results i in a further effect which makes it impossible to see the picture from a certain angle below or above a viewing plane which is essentially parallel to the spacers 2a. This effect is similar to the effect of i the lamellae la and therefore depends on the distance between the spacers 2a and on the distance to the viewer.

i Fig. 16 and 17 show spacers 2k and 21, respectively, which have different plan areas and thus permit inclination of the lamellae 11 for improved image reproduction when viewed obliquely from above, or an inclined position of the lamellae Im for reducing the blurring effect in the edge regions of the lamellar grid. The inclined position of the lamellae is related to the desired distance to the viewer: the lamellae im should each lie in a plane which also contains a direct connecting line between the eye of a viewer and the particular lamella im.

A cylinder 13 which is similar in function and pLtD i 4 structure (Fig. 2) contains lamellae Ic which are kept apart by acrylic glass 2f. They are cast in an acrylic glass block 5a. As a result of this embodiment, the lamellar grid is extremely robust, the spacers 2f not restricting the viewing plane. An embodiment in which the spacers 2 and lamellae 1 consist of silicone rubber permits high heat resistance in conjunction with low thermal expansion and also good adhesion. The production of the lamellae using adhesive is simple in production and in the reduced drying effort, which is otherwise involved when the layer faces 3a are coated.

Q As shown in the right-hand part of Fig. 2, the lamellae ic are made of dark or black metal. The surface of the block 5a is either smooth and without special features as shown there or as shown in the middle is provided with a surface structure 7, fcr example glass beads, which permit controlled diffusion or concentration of the light. In the lefthand part of the picture, the surface of the block Za i- provided with an antireflection coating 6, which is preferably polarizing. Usually, only one type of surface change is provided, but, in order to achieve certain effects, it is also possible to provide different surfaces, as shown in Fig. 3.

There, glass beads are shown on the left, which are either formed as a single piece with the acrylic glass block 5b or are adhesively bonded to the said block. An embodiment of the surface with concave recesses 8 can be seen next to this. There is also a section which is provided with anamorphotic lenses 9, which extend over the height of the entire lamellar grid or of the glass block 5b. They are convex.

However, it is also possible to provide concave embodiments. A cut area of the block 5b, which is provided with a Fresnel structure 10, is adjacent.

This structure permits a special parallel bundling of the emerging light.

Most effects due to lenses can also be produced if the glass is doped with different amounts of metal or metal oxide ions, as shown adjacent. Between the lamellae id, the acrylic glass in the left-hand area, close to the lamellae ld, is doped with ions 1la, in an amount which is essentially greater than in the centre region 12 between two adjacent lamellae id. Doping ilb is provided adjacent to this and increases towards the centre 12 between two adjacent lamellae id. As a result of the doping measures, the refractive index of the glass is changed, the glass being converted into a lens. Concentration of the metal ions in the centre region 12 corresponds to a convex embodiment; concentration at the edge adjacent to the lamellae Id corresponds to the concave embodiment of the surface of the glass block In the left-hand region of the glass block, the lamellae le do not extend to the surface of the block so that they are covered by glass even on their end face. This protects the lamellae from corrosion but may also lead to a light-mixing effect in the region between the surface and the end of the lamellae le. In the right-hand region, the lamellae id extend to the surface, with the result that each individual picture is sharply separated between two lamellae id. Like the spacers 2, the lamellae 1 can be formed from polarisation films. If adjacent films extinguish one another, the picture 15 is darkened as soon as the lamellae 1 overlap, owing to the inclined view of the viewer. This saves some light energy, since the lamellae 1 may themselves be transparent in the direction of their depth and do not absorb light like black surfaces. if adjacent polarisation films ~pL~L

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81 6 polarise in the same polarisation plane, the desired optical darkening effect is obtained when one polarisation film is simultaneously flatly superimposed on the grid, or the display field is enclosed all around by a polarisation film, as indicated with for example in Fig. 7. Of course, such a polarisation film could also be attached to the second outer cylinder, which is not shown.

In Fig. 4, the lamellae lb are essentially i 10 formed by colouring one side of a glass-like spacer 2b I or 2c. The individual spacers 2b or 2c are adhesively bonded to one another, one surface 3a of the spacer 2c being bonded to the surface 4a of the next spacer 2c, which surface is opposite the layer face 3a of the second spacer 2c. The spacers 2c are thus separated from one another by a layer of lamellae lb.

In Fig. 5, the surfaces 4a are shown partially free of lamellae. It is practical if the adhesive for Sbonding the spacers 2c is coloured dark, with the result that additional colouring of the spacers becomes superfluous.

In Fig. 6, the lamellae of metal, carbon coi-ecc, or extvApe_ w\C NeljoT e\c i laminate, hard paper or plastic le and If are/bended to ispacers 2e and 2d to form a honeycomb-like grid. The distances between the spacers 2e and 2d are chosen as large as possible in order to permit a large viewing angle. A honeycomb-like grid of this type appears similar to a system resembling expanded metal. It is also possible to cast such a grid in addition in transparent materials, resulting in extremely high stability. The spacers can also be straight, and, for example, a black-coloured grid of duraluminium with a wall thickness of 0.1 mm, 6 mm lamellar spacing, 10 mm spacer interval and 22 mm depth can be used. Such a grid could also be made up of elements (pixels) T

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)ca 7 separated off from a form tube. It is used in particular in large displays.

In contrast to the cylinder 13 in Fig. 1 and 2, the arrangement shown in Fig. 7 has a polarisation film 30 which, on the one hand, has an antireflective effect and on the other hand prevents viewing through the cylinder 13 parallel to the picture 15. In this viewing direction, the polarisation effect means that any light shining behind the cylinder 13 is darkened for the viewer. This prevents troublesome light reflection effects. Alternatively or in addition, it is possible to provide a shutter 34, which serves the same purpose. A good design is the following: c:d/2 0.4 to 0.8 (preferably where d is the width of the grid and c is the depth of the shutter or its extension over the cylinder 13. With respect to the circumference of the cylinder 13, the shutter should be /aout 8% o d xT Because the radiation angle of the lamellar grid or of the picture differs from zero, during rotation of the display field the viewer will also be able to see any regions which are covered by the shutter 34 when the picture is stationary and when viewing takes place from the front. In addition, a further lamellar grid 25 having lamellae 36 at right angles to the axis of rotation 14 is shown, the said lamellar grid likewise being mounted on the cylinder 13 or being connected to it to form a single piece. This lamellar grid 35 restricts the view of the picture in the vertical direction, so that the viewer of the picture is forced to view the picture horizontally. As a result, undesirable distortions due to shifts in the viewing angle are rendered invisible.

The spacers 2g and 2h in the embodiments according to Fig. 8 and 9 consist of solid material. A

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8 transparent plate 32 is provided with slots 31 into which the lamellae lh are inserted. It is of course also possible for a further plate with slots to be provided on the opposite side, analogously to plate 32; as shown in Fig. 8, this is, however, not absolutely essential. It is sufficient in many cases if as shown a cover plate 33 without slots is provided. It is practical if such a cover plate is provided with an antireflection coating 6 and/or with the surface changes already mentioned in connection with Fig. 3, for example with anamorphotic lenses 9. Since only some of the spacers 2g, h are present, a smaller amount of light is absorbed by "W0 them. If cover plate 33 were absent, a visible luminescent effect of the plate material on the side facing the viewer would furthermore be prevented, leading to better darkening.

The lamellae li according to Fig. 9 consist of paint or varnish or the like, which has been introduced, for example by immersion preferably in vacuo in a bath, followed by drying, into slots 31a in the broad face 37 and extending through about 75% of the thickness of a transparent closed plate 38 of glass or glass-like plastic. The face 37 is then polished. The slots 31a can be produced by means of a disc milling cutter, a jet, a laser beam or plasma cutting, or by appropriate casting EO£ during production of the plate 38. Since the slots 31a should be as thin as possible, it must be ensured that the paint or the varnish has only a low surface tension, in order to permit penetration into the slots. It is of course also possible to insert prefabricated lamellae into such slots 31a. The production process is also advantageous in particular for designs 1 25 in which the lamellae, in side view, do not have a rectangular shape or have different dimensions.

Because of the geometric angles encountered during rotation of the display field, it is advantageous if as shown in Fig. 10 the edge regions 42 are provided with narrower spacers, so that I 9 the radiation angles are smaller in the edge region of the lamellar grid than in the centre. If the radiation angles at the edge are too large (in relation to the total diameter of the lamellar grid), the result may be blurring of the picture in the edge region when it is not viewed from a sufficiently long distance. Measures such as, for example, those shown in Fig. 17 counteract this blurring. The following relationship applies: a:tan cc/2 b, where a is the distance between the lamellae, b is their depth and c is the desired radiation angle. This is advantageously 600. a is determined by the distance to the viewer; at a distance of more than 2 m, a spacing of about 1 mm is sufficient, so that in this case b 1.73 mm. Other conditions are of course also possible: for example, a "VCF" foil from Shin Etsu Polymer Co Ltd. can be used.

The spacers 2i in Fig. 11 which are in the form of fibre optical waveguides permit the production of a very compact lamellar grid having minimal radiation angles. The totally reflecting surface of the fibre optical waveguides acts as a lamella for the purposes of the invention. Such an arrangement also makes it possible to obtain digitalised picture representation if the individual fibre optical waveguides or groups of the individual fibre optical waveguides are activated separately by their own light sources. Since the fibre optical waveguides are flexible, the point at which the light sources (not shown) are mounted is freely variable.

Integration of the grid with the display field by combining individual cubic light elements 40 is shown in Fig. 12. The surface of the transparent elements 40 is first provided/with a ref±ective coating and then with a black coating or coloured by means of black adhesive and the said transparent elements are 7 combined in the direction of the arrows to form a mosaic of similar elements 40. The surface 41 which can be turned to face the viewer is then freed from paint and adhesive residues and is polished so that light can only be emitted through this area. The light can be produced by either light emitting diodes or small incandescent lamps preferably very small halogen lamps inside the elements 40. The lamps are indicated schematically with 43. The distance between the lamps and the surface 41 determines the radiation angle. In this case too, the individual fields can be activated separately, with the result that digital image contents can be represented. Such elements can be produced either by integral injection moulding with the lamps 43 or by cutting from prefabricated rod material, in which the blind holes for the lamps 43 are then drilled. If such a display grid is activated, for example, via a computer, several autonomously changing image displays are possible through its storage capacity, without the necessity of an external electrical connection to the non-rotating parts of the display means. In this case, the computer with the storage units would be rotated together with the grid.

The same applies to LCD and electroluminescence displays. The use of polarisation films in transmitted light LCD displays permits the random choice of a positive or negative display, by virtue of the fact that one of the polarisation films can be rotated.

If, in an electroluminescent screen, the spaces between the pixels coincide with the grid, the picture content is not reduced as a result. Advantageously, the grid pixels can be integrated directly in the screen.

The combination of two transparent plates 21a and 21b which is shown in Fig. 13 and used for

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7 11 supporting the lamellar grid 24 and a slide 20 has proved advantageous in assembly and for replacement.

Such combinations can usefully be prefabricated with different pictures, so that changing the picture contents in the display means merely requires a manipulation. Advantageously, the rotatable part of the display means is provided with a removable cover which carries a radial groove which positions and holds the combination in the correct axial position. The baseplate of the part has a diametrically opposite form. An antireflection coating 6 furthermore prevents undesirable reflections in this case. A slide is understood as being a transparency which preferably carries on its back a white coating for light diffusion. This coating can furthermore be varied depending on the colour of the light from the light source, in order to achieve optimal colour reproduction.

A similar combination is shown in Fig. 14, except that the rear transparent plate 21c is broader on its lower side and is connected to a plate 25 to form a single piece. The plate 25 has, on its lower side, a light inlet opening 23, which is located opposite an annular light source 16a. All outer surfaces of the plates 21c and 25 (22, 26) have been provided with a reflective coating, so that light can escape only through the slide 20 around the lamellar grid 24 or through the front transparent plate 21a.

The advantage of this variant arises from the fact that the light source does not rotate concurrently, with the result that the display means can be operated without slip rings. Light outlet openings 27, which are free of a reflective coating and direct light through the lamellar grid 24 and onto the picture 20, are provided in the front part of the plate 25. This gives rise to

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-12a mixed light effect (transmitted light and reflected light) at the picture which economically utilises the amount of light emitted by the light source 16a. The plates 21b and c are preferably UV-inhibiting where the light source 16 also emits UV radiation.

The design variant in Fig. 15 schematically shows a projector 29 and projection surface 19, which rotate together with the lamellar grid 24 lying in the axis of rotation 14. The projector 29 could also contain interchangeable pictures, which are interchangeable by remote control. By laterally displaying the projection surface 19 from the centre, the projector 29 can be brought as close as possible to the axis of rotation, so that the centrifugal forces remain small. It is critical that the lamellar grid 24 lies in the axis of rotation, and that only a little light energy is absorbed and converted into heat. It is desirable, for example, that the spacers do not absorb more than 20% of the light in any direction. The projection surface could of course also be curved. Since the projector must be concurrently rotated, a slip ring power supply is required.

The invention is in no way restricted by the Figures shown and their description. In particular, different imitation glass or mineral glass variants are therefore suitable as spacers. It is also possible to provide other metal or plastic constructions which serve as spacers. For example, it would also be possible to use lamellae with spacers made of paper or corrugated metal sheets rolled up into a drum for example as known in catalyst construction in the form of honeycomb sheets. Furthermore, the i 25 grid and the picture may also be slightly curved, at least in the edge S o regions. It is also possible to provide a matt finish as an antireflection S: coating.

if HRF/0509r

Claims (45)

1. Display means having a display field capable of carrying visual information and being adapted to be rotated about an axis within said display means at at least 500 revolutions per minute, said display field carrying a lamellar grid having a plurality of single lamellae at least substantially parallel to said axis, wherein spacers are arranged between each two of said single lamellae to keep said two of said single lamellae in their position relative to each other.

2. Display means according to claim 1, wherein the spacers are panes of transparent material, on one surface of which the lamellae are in the form of dark layers, each layer face of a pane being connected to the surface which is opposite the layer face of a further pane.

3. Display means according to claim 2, wherein the spacers are acrylic glass.

4. Display means according to claim 2, wherein the spacers are Sm silicone rubber.

5. Display means according to claim 2, wherein the dark layers are dark coloured adhesive.

6. Display means according to claim 2, wherein the dark layers are dark coloured silicone rubber.

7. Display means according to any one of the preceding claims, wherein the lamellae are formed by a polarisation film.

8. Display means according to any one of the preceding claims claims, wherein adjacent lamellae obscure one another when viewed in o transmitted light.

9. Display means according to any one of the preceding claims, wherein a further polarisation film is arranged to enclose the display l field.

10. Display means according to either claim 1 or claim 7, wherein the lamellae are enclosed or cast in a pane-shaped block of transparent material.

11. Display means according to either claim 1 or claim 7, wherein the spacers are arranged only over partial areas of the lamellae, and are retained against the lamellae.

12. Display means according to claim 11, wherein the lamellae are held in slots of a transparent plate against said display field. IAD/ 1190o i F L 14

13. Display means according to any one of claims 1 to 10, wherein t;ie spacers are connecting webs which may be bent and/or staggered with respect to one another and which connect to one another between adjacent lamallae, and are oriented in one direction to form a honeycomb plate having rectangular or hexagonal honeycombs.

14. Display means according to any one of claims 1 to 10, wherein the spacers are connecting webs which may be bent and/or staggered with respect to one another and which connect to one another between the lamallae, and are oriented in one direction to provide a lattice structure resembling expanded metal. Display means according to claim 13, wherein the honeycomb plat consists of carbon laminate.

16. Display means according to claim 13, wherein the honeycomb plat consists of hard paper. e p. 9 re .9 9 99 p9 e

17. Display means according to claim 13, consists of black-coloured aluminium foil.

18. connected t(

19. connected t( connected t(

21. o, 20, wherein c rectanguliar

22. Display means o one another Display means o one another Display means o one another Display means the lamellae or hexagonal Display means according to claim 13, by adhesive bonding. according to claim 13, by soldering. according to claim 13, by welding. wherein the honeycomb plate wheyrin the honeycombs are wherein the honeycombs are wherein the honeycombs are according to claim 13 or any one of claims 15 to and spacers define a region consisting of pixels. according to any one of the preceding claims, 9. 9 9 9 a 09 .9 9 S 99 9>, wherein the lamellar grid, or cover plates connected to said lamellar grid has or have, on its or their front and/or back, an antireflection and/or a polarising coating.

23. Display means according to claim 22, wherein said grid or said cover plates is or are provided with an optical concentrating system.

24. Display means according to claim 23, wherein said optical concentrating system comprises glass beads. Display means according to claiim 23, wherein said optical concentrating system comprises concave recesses. IAD/ 1190o 15

26. Display means according to claim 23, wherein said optical concentrating system comprises anamorphotic lenses.

27. Display means according to claim 23, wherein said optical concentrating system comprises a Fresnel structure.

28. Display means according to claim 23, wherein said optical concentrating system is formed by different degrees of doping of the transparent material with suitable metal ions or metal oxide ions. 2' Display means according to claim 28, wherein said optical concentrating system is formed with each transparent material between adjacent lamellae having a light concentration increasing towards the jcentre. I c 30. Display means according to any one of the preceding claims, wherein the lamellae are formed by totally reflecting lateral surfaces of i fibre optical light guides at right angles to the display field, while the i fibres themselves form the spacers in their radial extension. S31. Display means according to any one of the preceding claims, wherein the spacing between the lamellae varies over the width of the lamellar grid.

32. Display means according to any one of the preceding claims, i, wherein the spacing between the lamellae becomes smaller towards the edge ii D of the display field. i 33. Display means according to any one of the preceding claims, wherein the edge regions of the display field are capable of emitting light i c With a higher light density than the central regions. *34. Display means according to any one of the preceding claims, the display field being arranged in a transparent cylinder in such a way that it can rotate about a vertical axis and can be illuminated from behind by a B light source, which is invisible from the outside as a result of shielding, characterised in that a region of about 5 to 15% of the inner circumference of the cylinder at the side of the display field is darkened in a direction towards a viewer by means of a shutter. Display means according to claim 34, wherein said region is about 8% of the inner circumference of the cylinder at the side of the display field. IAD/1190o 1 16

36. Display means according to any one of the preceding claims, wherein the inner or outer wall of the cylinder is lined with a polarisation film and is provided with a further lamellar grid whose lamellae extend horizontally.

37. Display means according to any one of the preceding claims, having a transmitted light LCD display, with a first polarisation film mounted behind and a second polarisation film, characterised in that the second polarisation film is arranged on the cylinder.

38. Display means according to any one of claims 1 to 36, further provided with a slide, wherein the lamellar grid and the slide are clamped between two transparent plates.

39. Display means according to claim 38, wherein one of said transparent plates faces a light source of said display means, said light source being placed in a non-rotatable part of the display means, said one transparent plate being translucent or opal. Display means according to claim 38, wherein one of said transparent plates faces a light source ofsaid display means and is in the form of a light-guiding plate having four lateral surfaces, which project from the slide and are reflective whilst a fifth lateral surface is in the form of a light inlet surface and wider than the four lateral surfaces.

41. Display means according to claim 40, wherein the light source is placed in the non-rotatable part of the means, opposite said light inlet surface. 9. 42. Display means according to claim 40, wherein the wider part of S the light inlet surface is connected to a further plate to form a single piece, said plate extending over the greatest part of the horizontal projection area of the rotatable display field, the sides of the said area, with the exception of the light inlet side being totally reflecting.

43. Display means according to claim 42, wherein light outlet openings are provided in the region in front of the display field or slide, through which openings light can strike the display field at an angle through the lamellar grid.

44. Display means according to claim 43, wherein said light outlet openings are bevelled. Display means according to any one of claim 1 to 36, wherein the lamellar grid is connected rigidly to the surface of an electroluminescent r 0 IAD/1190o 17 screen or forms a single piece with the said screen, the lamellae and spacers being arranged so that they are essentially in alignment with the spaces between the pixels of the electroluminescent screen.

46. Display means according to any one of claims 1 to 36, wherein the lamellar grid is positioned so that it passes through the axis of rotation, characterised in that the picture can be projected from a concurrently rotatable projector onto a projection area located behind the lamellar grid, and that the spacers do not absorb more than 20% of the light in any direction.

47. Display means according to any one of the preceding claims, wherein the spacers and the lamellae vary in their depth over the height of the lamellar grid.

48. Display means according to claim 47, wherein the lamellar spacers are arranged at right angles to a surface formed by the edges of j the lamellae which are adjacent to one another, that surface being able to be turned to face the viewer.

49. Display means according to any one of the preceding claims, wherein the spacers are smaller towards the edge of the lamellar grid, to enable the lamellaes to be closer together. Display means according to claim 49, wherein the lamellae form, with the plane of the display field, an angle which varies over the width of the lamellar grid.

51. A process for the production of a lamellar grid for a display means according to any one claims 1, 2 to 6, 10 or 31 to 50, wherein a transparent plate of glass or glass-like plastic is provided, through about of its thickness, with thin, parallel grooves, which are then filled with a dark lamellae-forming material by immersion preferably in vacuo I in a bath after which, following drying, at least the groove- carrying surface of the plate is polished.

52. Process for the production of a lamellar grid for a display means according to claim 51, wherein the dark lamellae-forming material is inserted into the grooves by immersion in vacuo.

53. Process for the production of a lamellar grid for a display means according to any one of claims I, 2 to 6, 10, 22 to 34, or 47 to wherein the lamellar grid is integrated with the display field by combining a plurality of elements which are self-luminous and have a planar surface. I I 0 PIAD/11900 B 18

54. A process according to claim 53, wherein said elements are light emitting diodes. ,I 55. A process for the production of a lamellar grid for a display means according to claim 53, wherein said elements are plastic cubes containing incandescent lamps or the like.

56. A process according to claim 53, wherein said elements are i coloured or coated on all sides by immersion coating, after which they are i adhesively bonded parallel to one another to form the lamellar grid which simultaneously serves as the display field, after which the surface which can be turned to face the viewer is freed from coating or adhesive films and is polished.

57. A process according to claim 56, wherein said elements are 1 adapted reflect light and absorb light to provide a black appearance.

58. A process according to claim 56, wherein said adhesive S simultaneously acts as the black colour.

59. Display means substantially as hereinbefore described with reference to the drawings. A process for the production of a display means substantially as hereinbefore described with reference to the drawings. DATED this TNENTY-FIRST day of MARCH 1991 Technolizenz B.V. and Kurt F. Buchel o SPatent Attorneys for the Applicants iii SPRUSON FERGUSON IAD/1190o 1 c 19 List of reference symbols 1 Lamella a-k, 1, m i 2 Spacer a-i, k 3 Layer face a 4 Surface a Block a, b i 6 Antireflection coating 7 Glass beads 8 Concave recesses 9 Anamorphotic lenses Fresnel structure 11 Ion doping a, b 12 Centre i 13 Cylinder 14 Axis Picture 16 Light source 17 Reflective coating 19 Projection area Slide 21 Transparent plate b, c) 22 Four lateral surfaces 23 Fifth lateral surface 24 Lamellar grid Plate 26 Sides 27 Light outlet openings 28 Light 29 Projector Polarisation film 31 Slot a 32 Transparent plate 33 Cover plate 34 Shutter Further lamellar grid L. I 36 Its lamellae 37 Broad face 38 Plate 39 Adhesive Element 41 Surface 42 Edge regions 43 Lamp COI 1 rE 21 ABSTRACT The invention relates to a display means having an information-bearing display field which carries a lamellar grid for orienting light beams or for preventing the possibility of lateral viewing of a picture. The display field is rotatable in all directions about an axis According to the invention, the lamellar grid is provided with spacers between the lamellae This ensures great stability of the display means, even at high rotary speeds. The spacers can be lamellar webs or i. transparent discs. S (Fig. 1)