WO1988009546A1

WO1988009546A1 - Display device with a display field and a lamellar grid, process for producing the lamellar grid

Info

Publication number: WO1988009546A1
Application number: PCT/CH1988/000098
Authority: WO
Inventors: Jan Secka; Kurt F. BÜCHEL
Original assignee: Technolizenz B.V.
Priority date: 1987-05-21
Filing date: 1988-05-24
Publication date: 1988-12-01
Also published as: EP0314730A1; JPH01503812A; AU611156B2; AU1720688A; DE8890059U1

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 (14). The lamellar grid is provided with spacer blocks (2) between the lamellas (1), ensuring a high stability of the display device even at light rotational speeds. The spacer blocks may be lamellar bridges or transparent disks.

Description

Display device with a display field and a lamella grid, and method for producing the lamella grid

The invention relates to a display device according to the preamble of claim 1. Such a display device is known from EP-A-208283, which is hereby considered to be disclosed in the context of this description. The lamella grid causes an optical image to be separated in such a way that it can always be seen completely from only one limited radiation angle. However, if the picture is viewed from an oblique angle, it is invisible or darkened for the viewer. In such a case, the viewer only sees the slats that seem to have a gap. The following rule applies: the smaller the radiation angle and the greater the distance from the viewer, the sharper - but also 'fainter' - the picture is. In the mentioned EP-A-208283, louvre-like slats are described which in practice have not proven to be sufficiently stable when the speed of rotation has increased. A lack of rigidity of the lamellas often led to image distortion or an impure transition from the visibility phase of the image to its invisibility phase during a complete rotation.

The object of the invention is therefore to design the lamella grid so that it has sufficient stability in all directions, even at high speeds of rotation. In addition, vibrations of the lamellae which may occur should be prevented. In the display device hin¬ made to the louvre as such separate from the usual ^'ring components produced or easily be mountable. All of these tasks are solved in a satisfactory manner by the features of claim 1. Various advantages and further design variations are described in the characteristics of the subclaims and the description of the figures:.

The invention is explained in more detail by way of example with reference to the drawing. It show

1 shows a display device on which individual spacers have been attached;

2 shows an enlarged representation of the slats cast into a block;

3 shows a plan view of a one-piece casting block with a different design of its surface, partially cut;

4 shows a single spacer made of transparent material;

Fig.5 two spacers, partially cut out, and

6 shows a honeycomb grid with metal spacers.

7 measures on a rotary cylinder to improve the optical raster properties,

Fig. 8-12 different grid variants,

Fig.13-15 combination arrangements of grids and image and the

Fig. 16 and 17 grid with changed optical parameters.

An image 15 illuminated by a light source 16 is located within a cylinder 13 (FIGS. 1 and 7) in a plane through the axis 14 of the cylinder. Provided between the image 15 and the light source 16 is a grid of lamellae 1a parallel to the axis 1. The slats 1a are spaced apart from one another by flat metal spacers 2a. hold. The spacers lie in different planes which extend normally to the axis 14. The picture could also be mounted directly between the slats.

The cylinder 13 is essentially transparent, but is mirrored on the side 17 facing the light source on the inside or outside. The cylinder is rotated by a drive unit, not shown, so that the image is visible all around. The display field formed by the image and raster could also be rotated on its own (in particular in the case of LCD or electroluminescent displays), but in the case of transmitted light images, the light source 16 must in any case be darkened on its side facing away from the image. However, a construction that combines transmitted light and incident light is also within the scope of the invention. A further cylinder, not shown, could also serve as a housing around the cylinder 13, at least as a dust cover.

Even with high centrifugal forces, the lamellae 1a cannot deflect laterally, since they support each other via the spacers 2a. The planar arrangement of the spacers 2a also provides a further effect which prevents the image from being seen 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 the lamellae 1a and therefore depends on the distance between the spacers 2a and on the distance of the viewer.

16 and 17 show spacers 2k and 21, respectively, which have different floor plan areas and thus an inclination of the slats 11 for improved image reproduction from an oblique view from above, or an inclination of the slats 1m to reduce the Allow blurring effect in the edge areas of the lamella grid. The sloping position of the slats corresponds to the desired distance from the viewer: The slats 1m should each lie in a plane in which there is also a direct connecting line between the viewer's eye and the respective Iiamelle Im.

A cylinder 13 (FIG. 2) which is identical in function and structure contains lamellae 1c which are kept at a distance by acrylic glass 2f. They are cast in an acrylic glass block 5a. This design makes the lamella grid extremely robust, with the spacers 2f not restricting the viewing plane. Forming the spacers 2 and lamellae 1 from silicone rubber enables high temperature resistance with low thermal expansions and at the same time good adhesion. The lamella formation by means of adhesive is simple to manufacture and reduces the amount of drying that would otherwise occur when painting the layer surfaces 3a.

The fins 1c are, as shown in the right part of FIG. 2, made of dark or black metal. The surface of the block 5a is either - as just shown there - smooth and without any special features or - as shown in the middle - with a surface structure 7, for example glass beads, which allow targeted diffusion or focusing of the light. In the left part of the picture, the surface of block 5a is coated with a reflection-reducing coating 6, which preferably has a polarizing effect. Usually only one type of surface change is always provided, but different surfaces can also be provided in order to achieve certain effects, as can also be seen from FIG.

There are glass beads on the left, which are either formed in one piece with the acrylic glass block 5b, or else are glued to the latter. In addition, one can see a configuration of the surface with concave recesses 8. Next to this is a section which has anamorphic lenses 9 is provided, which extend over the entire height of the lamella grid or the glass block 5b. They are convex. However, concave designs could also be provided. Next to it is a cut area of block 5b, which is provided with a Fresnel structure 10. This structure enables special parallel bundling of the emerging light.

Most of the effects of lenses can also be produced in that the glass has a different doping level of metal or metal oxide ions, as shown next to it. Between the lamellae 1d, the acrylic glass in the left area, in the vicinity of the lamellae 1d, is provided with an ion doping 11a which is substantially higher than in the area of the center 12 between two adjacent lamellae 1d. In addition, a doping 11b is provided, which increases towards the center 12 between two adjacent lamellae 1d. The refractive index of the glass is changed by the doping measures in the sense of forming it as a lens. A concentration of the metal ions in the area of the center 12 corresponds to a convex configuration; a concentration at the edge next to the lamellae 1d corresponds to a concave formation of the surface of the glass block 5b.

In the left area of the glass block, the lamellae 1e are not extended to the surface of the block 5b, so that they are also covered by glass on their end face. This protects the fins from corrosion, but may also lead to a light mixing effect in the area between the surface and the end of the fins 1e. In the right-hand area, the slats 1d are pulled through to the surface, as a result of which each individual image between two slats 1d is sharply separated. The slats 1, like the spacers 2, can be formed from polarization foils. If adjacent foils are polarized to extinguish each other, the image 15 darkens as soon as the lamellae 1 become oblique due to the oblique view of the viewer. ters cover. This saves some light energy, since the slats 1 themselves can be transparent in the direction of their depth and do not swallow light like black surfaces. If adjacent polarizing foils are polarizing in the same polarization plane, the desired optical darkening effect occurs when at the same time a polarizing foil is superimposed on the grid, or the display field is completely surrounded by a polarizing foil, as is the case in Fig. 7 indicated with 30. Of course, such a polarizing film could also be attached to the second outer cylinder, not shown.

In FIG. 4, the lamellae 1b are essentially formed by coloring one side of a glass-like spacer 2b or 2c. The individual spacers 2b and 2c are glued to one another, one surface 3a of the spacer 2c being glued to the surface 4a of the next spacer 2c, which is opposite to the layer surface 3a of the second spacer 2c. The spacers 2c are thus separated from one another by a layer of lamellae 1b.

5 shows the surfaces 4a partially without lamellae. Conveniently, the adhesive for connecting the spacers 2c is colored dark, as a result of which the additional coloring of the spacers is superfluous.

In FIG. 6, the lamellae made of metal, carbon laminate, hard paper or plastic 1e and 1f are connected with spacers 2e and 2d to form a honeycomb grid. The distances between the spacers 2e and 2d are chosen to be as large as possible in order to enable a large viewing angle. Such a honeycomb grid looks like an expanded metal-like system. It is also conceivable to additionally incorporate such a grid into transparent materials. sen, which results in extreme stability. The spacers can also be straight, it being possible, for example, to use a black-colored grid made of duralumin with 0.1 mm wall thickness, 6 mm lamella spacing, 10 mm spacer spacing and 22 mm depth. Such a grid could also be constructed from elements (pixels) separated from a shaped tube. It is used particularly in large advertisements.

The arrangement shown in FIG. 7, in contrast to the cylinder 13 according to FIGS. 1 and 2, has a polarizing film 30 which, on the one hand, produces an anti-reflective coating and on the other hand prevents the cylinder 13 from being viewed parallel to the image 15. In this viewing direction, the polarization effect darkens any light shining behind the cylinder 13 for the viewer. This prevents disruptive light reflection effects. Alternatively or in addition, an aperture 34 can be provided, which serves the same task. A good design is: c: d / 2 = 0.4 to 0.8 (preferably 0.6), where d is the width of the grid and c is the depth of the diaphragm or its extension over the cylinder 13. Seen from the circumference of the cylinder 13, the aperture should make up about 8% of dxπ.

Due to the non-zero radiation angle of the lamella grid or the image, when the display panel rotates, those areas are also made visible to the viewer which are covered by the aperture 34 when the image is stationary when viewed from the front. In addition, a further lamella grid 25 with lamellae 36 perpendicular to the axis of rotation 14 can be seen, which is likewise applied to the cylinder 13 or is integrally connected to it. This lamella grid 35 limits the top view to the image 15 in the vertical direction, so that its viewer is forced to view the image horizontally. As a result, undesirable distortions caused by shifts in the viewing angle are made invisible. The spacers 2g and 2h according to the training according to Figures 8 and 9 are made of solid material. In this case, slots 31 are made in a transparent plate 32, into which the slats 1h are inserted. Of course, analogous to plate 32, a further plate with slots could also be provided on the opposite side; however, as can be seen from FIG. 8, this is not absolutely necessary. In many cases it is sufficient if, as shown, a cover plate 33 is also provided without slots. Such a cover plate is expediently provided with a reflection-reducing coating 6 and / or with the surface changes already mentioned in FIG. 3, for example with anomorphic lenses 9. Because of the spacers 2g, h which are only partially present in this way, only one of them is ge Amount of light absorbed. In the absence of a cover plate 33, a visible afterglow effect of the plate material on the side facing the viewer would also be prevented, which leads to better darkening.

The slats 1i according to FIG. 9 consist of paint or varnish or the like, which has been introduced into slots 31a in the wide area 37 of a closed plate 38. The slots 31a can be produced by means of disc milling cutters, jet beams, laser beams, plasma cutting or even during the manufacture of the plate 38 by means of appropriate casting molds. Since the slits 31a should be as thin as possible, care must be taken to ensure that the paint or lacquer has only a low surface tension in order to allow penetration into the slits. Of course, prefabricated slats can also be inserted into such slots 31a. The manufacturing process is also particularly suitable for those constructions in which the lamellae in the side view have no rectangular shape or different dimensions. Due to the geometrical angular relationships during the rotation of the display panel, it is advantageous if - as can be seen from FIG. 10 - the edge areas 42 are provided with narrower spacers, so that the radiation angles in the edge area of the lamella grid are smaller than in the middle. If the radiation angles at the edge are too large (depending on the overall diameter of the lamella grid), this can lead to a blurring of the image in the edge area if the viewing distance is not sufficiently long. Measures, such as shown in FIG. 17, counteract this blurring. The following relationship applies: a: tan α / 2 = b, where a is the distance between the slats, b their depth and α the desired radiation angle. This is conveniently at 60 °. a is determined by the distance of the observer; at a distance of more than 2m, about 1mm distance is sufficient, so that in this case b = 1.73mm. Other conditions are of course also possible: for example, a film "VCF" from Shin Etsu Polymer Co Ltd. be used.

The spacers 2i in the form of optical fibers according to FIG. 11 permit the production of a very compact lamella grid with minimal radiation angles. The total reflecting surface of the optical fibers acts like a lamella in the sense of the invention. Such an arrangement also enables digitized image display if the individual optical fibers or groups of the individual optical fibers are controlled separately by their own light sources. Since the optical fibers are flexible, the location of the fastening light sources, not shown, can be freely selected.

The integration of the grid with the display field by assembling individual cubic light bodies 40 is shown in FIG. The transparent bodies 40 are first coated on their surface in a reflective manner and then black or colored with black adhesive and in the direction of the Arrows joined together to form a mosaic of similar bodies 40. The surface 41 which can be turned towards the viewer is then freed from polishing and adhesive residues and polished, so that light can be emitted exclusively through this surface. The light is generated either by light emitting diodes or small incandescent lamps - preferably small halogen lamps - inside the body 40. The lamps are schematically indicated at 43. The distance of the lamps from the surface 41 is responsible for the radiation angle. Here, too, the individual fields can be controlled separately, which means that digital image content can be displayed. Such bodies 40 can be produced either by injection molding integrated with the lamps 43 or by cutting prefabricated rod material into which the blind holes for the lamps 43 are subsequently drilled. If such a display grid is controlled, for example, by means of a computer, several autonomously changing image displays are possible via its storage capacity without an external electrical connection to the non-rotating parts of the display device being necessary. In this case, the computer with the storage units would also be rotated with the grid. The same applies to LCD or electroluminescent displays. The use of polarizing foils in transmitted-light LCD displays enables the arbitrary selection of a positive or negative display in which one of the polarizing foils can optionally be turned over.

If the interspaces of the pixels are congruent with the grid in an electroluminescent screen, the image content is not reduced as a result. The raster pixels can advantageously be integrated directly into the screen.

The combination of two transparent plates 21a and 21b shown in FIG. 13 for supporting the lamella grid 24 and a Diaposi.tives 20 has proven to be advantageous in assembly and for replacement. Such combinations can be sensibly prefabricated with different images, so that the exchange of the image contents in the display devices requires only one movement. The rotatable part of the display device is advantageously provided with a removable cover which radially carries a receiving groove which positions and holds the combination in the correct axial direction. The base plate of the part is designed in opposite directions. A reflection-reducing coating 6 also prevents unwanted reflections in this case. A transparency is to be understood as a transparency, which preferably has a white coating on the back for light diffusion. This coating can also be varied depending on the light color of the light source in order to achieve optimal color rendering.

A similar combination is shown in FIG. 14, with the difference that the rear transparent plate 21c is widened on its underside or is integrally connected to a plate 25. The plate 25 has on its underside a light entry opening 23 which is opposed to an annular light source 16a. All outer sides of the plates 21c and 25 (22, 26) are mirrored, so that only light can escape through the slide 20 around the lamella grid 24 or through the front transparent plate 21a. The advantage of this variant results from the fact that the light source is not rotated, which means that the display device can operate without a slip ring. In the front part of the plate 25, light exit openings 27 are provided which are free of mirroring and throw light through the lamella grid 24 onto the image 20. This results in a mixed light effect (transmitted light and incident light) on the image 20, which economically utilizes the amount of light emitted by the light source 16a. The plates 21b and c are preferably UV radiation-inhibiting insofar as the light source 16 also emits UV rays. The design variant according to FIG. 15 schematically shows a projector 29 and a projection surface 19 which rotate with the lamella grid 24 lying in the axis of rotation 1. The projector 29 could also contain alternating images that can be exchanged via a remote control. By displacing the projection surface 19 from the center, the projector 29 can be brought as close as possible to the axis of rotation so that the centrifugal forces remain small. Is crucial _/ that the louver 24 is located in the axis of rotation. And that only a little light energy is swallowed or converted into heat. The projection surface could of course also be curved. Since the projector has to be 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 synthetic or mineral glass variants can be used as spacers. Other metal or plastic constructions can also be provided, which serve as spacers. For example, slats with spacers made of paper or corrugated sheets rolled up into a drum - e.g. known in catalyst construction - conceivable in the form of honeycomb panels. In addition, the raster and image can also be slightly curved, at least in the edge areas. The anti-reflective coating can also be carried out using a matt lacquer.

Claims

PATENT CLAIMS

1. Display device with a display field carrying information, the image (15) of the display field being able to be turned in different directions with the aid of an image movement device, and wherein a lamella grid made up of individual ones on the front or on the back of the image (15) Slats (1) is arranged, through which preferably the axis of rotation (14) of the display panel passes, characterized in that spacers (2) are arranged between the slats (1).

2. Display device according to claim 1, characterized in that the spacers (2b, c) are disks made of transparent material - optionally made of acrylic glass or silicone rubber - on each of which one surface (3a) the lamellae (1b ) are formed as dark layers - optionally made of dark-colored adhesive or silicone rubber, each layer surface (3a) of one pane being connected to the surface (4a) opposite the layer surface (3a) of another pane. (Fig. 4,5)

3. Display device according to claim 1, characterized in that the lamellae (1g) are formed by a polarizing film, preferably mutually adjacent lamellae (1g) polarizing by extinguishing each other, and wherein optionally a further polarizing film (30) closed around the Display field (15) is arranged. (Fig. 3,7)

4. Display device according to claim 1 or 3, characterized gekenn¬ characterized in that the slats (1) in a disc-shaped block (5) of transparent material are enclosed or cast. (Fig. 2,3,7)

5. Display device according to claim 1 or 3, characterized gekenn¬ characterized in that the spacers (2g, h) are arranged only over partial areas of the slats (1h, i), the slats (1h, i) - for example in slots (31) of at least one transparent plate (32) - are held captive. (Fig.8.9)

6. Display device according to claim 1, characterized in that the spacers (2a, e) - optionally kinked and / or mutually offset - are connecting webs, which are oriented in one direction slats (1e, f) of a honeycomb panel, preferably with rectangular or six-sided Connect honeycombs, or a mesh structure similar to expanded metal, or that the slats (1) and spacers (2) are constructed from rectangular or hexagonal pixels, the honeycomb plate or the pixels preferably made of carbon laminate, hard paper or black-colored aluminum foil are constructed and are preferably connected to one another by adhesive bonding, soldering or welding.

7. Display device according to one of the preceding claims, characterized in that the lamella grid or cover plates (33) connected thereto have a reflection-reducing and / or polarizing coating (6) and / or characterized on its or their front and / or rear ,

^" that it has or has an optical bundling system, such as glass beads (7), concave recesses (8), anamorphic lenses (9) or a Fresnel structure (10), or preferably by differently doping the transparent material with suitable metal or metal oxide ions (11) is formed, each transparent material between adjacent lamellae (1d) in particular having an increasing concentration in the direction of the center (12). (Fig. 2,3,8)

8. Display device according to one of the preceding claims, characterized in that the lamellae (1k) through the to¬ tal reflecting lateral surfaces from perpendicular to the image surface standing optical fibers are formed, while the fibers themselves form the spacers (2i) in their radial extension. (Fig.11)

9. Display device according to one of the preceding claims, characterized in that the spacing of the slats from one another varies over the width of the slat grid, in particular towards the edge (42) of the display panel (15), which edge regions (42) of the display panel (15) are preferably able to radiate with a greater light density than the central areas. (Fig.10)

10. Display device according to one of the preceding claims, wherein the display panel is arranged in a transparent cylinder so as to be rotatable about a vertical axis and can be illuminated on its rear side by a light source which is not visible from the outside due to shielding, characterized in that a range of approximately 5 to 15%, preferably approximately 8% of the inner circumference of the cylinder (13) to the side of the display field is darkened in the direction of an observer by a screen (34), and / or that the interior or exterior Wall of the cylinder (13) with a polarizing film (30) is provided with a further lamella grid (35), the lamellae (36) of which extend horizontally. (Fig.7)

11. Display device according to one of the preceding claims, with a transmitted light LCD display, with a first polarization film applied behind it and a second polarization film, characterized in that the second polarization film (30) is arranged on the cylinder (13) is.

12. Display device according to one of claims 1 to 10, with a slide (20), characterized in that the Lamel¬ lenraster (24) and the slide (20) are clamped between two transparent plates (21a, b, c), where the - placed in the non-rotating part of the device - light Source (16) facing plate (21b) is preferably translucent bis-opal, or the plate (21c) facing the light source (16a) is designed as a light-guiding plate, the four sides of which project from the slide (20) surfaces (22) are designed to be reflective, while the fifth side surface (23) is designed as a light entry surface - in particular widened - which is preferably placed opposite the light source (16a) in the non-rotatable part of the device. (Fig. 13, 14)

13. Display device according to claim 12, characterized in that the widened part of the light entry surface (23) is integrally connected to a plate (25) which extends over most of the plan area of the rotatable display field, the sides (26) of which With the exception of the light entry side (23), they are designed to be totally reflective, with light exit openings (27), preferably beveled, being provided in the area in front of the image or slide (20) through which light (28) passes through at an angle through the Louvre grid (24) can meet the image (15). (Fig.14)

14. Display device according to one of claims 1 to 10, characterized in that the lamella grid is rigidly or integrally connected to the surface of an electroluminescent screen, wherein the lamellae (1) and spacers (2) are arranged so that they essentially with the spaces between the pixels of the electroluminescent screen are aligned.

15. Display device according to one of claims 1 to 10, wherein the lamella grid is placed through the axis of rotation (14), characterized in that the image from a rotatable projector (29) can be projected onto a projection surface (19) located behind the lamella grid and that the spacers (2) do not have a light absorption behavior greater than 20% in any direction. (Fig.15) 16. Display device according to one of the preceding claims, characterized in that the spacers (2k) and the slats (11) vary in depth over the height of the slat grid, in the case of slat-like spacers these preferably at a right angle to that Surface are arranged, which is formed by the mutually adjacent edges of the slats (11) facing the viewer. (Fig.

16)

17. Display device according to one of the preceding claims, characterized in that the spacers (21) are trapezoidal in plan, preferably with a flatter leg angle towards the edge of the lamella grid, and that the lamellae (1 m) overlap with the image plane the width of the lamella grid includes different angles. (Fig.17).

18. A method for producing a lamella grid for a display device according to claim 1, 2, 4, or 9 to 17, characterized in that a transparent plate (38) made of glass or glass-like plastic has a thickness of approximately 75% with thin, parallel grooves (36), which are then filled by dipping - preferably under vacuum - into a bath with a dark-colored lamellar material, after which at least the surface (37) of the plate (38) carrying the grooves (36) is polished becomes.

(Fig.9)

19. A method for producing a lamella grid for a display device according to claims 1, 2, 4, 7 to 10, 16 and. 17, characterized in that the bodies (40) self-luminous bodies with a flat surface, for example light-emitting diodes, plastic cubes with inserted incandescent lamps or the like, are preferably firstly reflective on all sides and then dark (if necessary black) colored (coated) , After which they form a parallel to each other to form the lamella grid forming the display field. are glued, the adhesive (39) preferably being able to take on the black color at the same time, and then the surface (41) which can be turned towards the viewer is freed from the coloring or adhesive layers and polished. (Fig.12)

Reference list

Lamella ak, l, m; Spacers ai, k; Layer area a; Surface a; Block a, b; anti-reflective coating; Glass beads; concave recesses; anamorphic lenses; Fresnel structure; Ion doping a, b; Center; Cylinder; Axis; Image; Light source; Mirroring; Projection surface; Slide; Transparent plate; (a, b, c) four side faces; Fifth side surface; Lamella grid; Plate; Pages; Light exit openings; Light; Projector; Polarizing film; Slots a; Transparent plate; Cover plate; Cover; further lamella grid; whose slats; Broad area; Plate; 39 glue; Body; Surface; Marginal areas; Lamp;