DE102009054706B4 - device for spatial representation - Google Patents

Abstract

Device for spatial representation, comprising - an image display unit (1) with image elements x(i,j) which are arranged in a grid with rows (j) and columns (i), and on which information from at least two views A(k) with k=2,...,N and N of a natural number can be displayed, - a lenticular disk (4) arranged in front of it in the viewing direction of a viewer (3) with lenticular (5) and separation areas (6) arranged next to one another, alternating with one another and periodically along a main direction, wherein light propagation directions for light coming from the image elements x(i,j) are predetermined by means of the lenticular areas (5), whereby the viewer (3) sees at least predominantly a first selection from the views A(k) with one eye and at least predominantly a second selection from the views A(k) with the other eye from a plurality of viewing positions in front of the grid of image elements x(i,j), thus creating a spatial visual impression for the viewer (3). is created,- an optical barrier structure (7) arranged in front of the image display unit (1) in the direction of view of the viewer (3) to improve the spatial visual impression,- wherein the barrier structure (7) consists of opaque areas arranged next to one another, in front of or behind the lenticular pane (4) with the effect of a strip-shaped barrier,- wherein each opaque area at least partially covers a separation area (6).- characterized in that- in a first alternative, the barrier structure (7) is applied to a separate barrier carrier substrate (8) located between the image display unit (1) and the lenticular pane (4) or- in a second alternative, from the direction of a viewer (3), a transparent cover (11) is arranged in front of the lenticular pane (4), on the side of which facing away from the viewer (3) the barrier structure (12) is applied.

Description

The invention relates to a device for spatial representation. Such a device comprises an image display unit with image elements x(i,j) which are arranged in a grid with rows (j) and columns (i) and on which information from at least two views A(k) with k=2,...,N and N a natural number can be displayed. A lenticular disk is arranged in front of this image display unit in the viewing direction of a viewer. This lenticular disk has lenticular and separation areas along a main direction, which is usually the horizontal but can generally also include all directions that deviate from the vertical, which are arranged next to one another, alternating with one another and periodically. Each lenticular area is therefore surrounded by two separation areas and vice versa.

Lenticular disks are usually made up of lenticular lenses or grids of such lenticular lenses, i.e. of lenses in the shape of a half cylinder, the convex surface of which faces outwards towards the observer. In this case, the separation areas are very small, essentially linear. For the purposes of the invention, however, the term "lenticular disk" is not only to be understood as referring to such arrangements of lenticular lenses in the classical sense, but also to such arrangements with which essentially the same effect can be achieved, but which are not composed of strictly cylindrical lenses with linear separation areas, but of - in relation to the viewing direction of an observer - convexly shaped lenticular areas and different, for example concavely shaped and noticeably extended separation areas. Such arrangements can be made, for example, with the device described in the unpublished German patent application DE 10 2009 019 762 A1 - the entire disclosure of which is expressly incorporated herein by reference - can be produced very inexpensively. In this case, convex lenticular regions and concave separation regions alternate, the transitions between lenticular regions and separation regions are smooth, ie a function describing the surface can be continuously differentiated at least once at every point.

In the US 2008/0259157 A1 An autostereoscopic imaging device based on lenticular elements is described, whereby the light transmission through the lenticular elements is limited by means of a repeating pattern. The US 2009/0262419 A1 describes a device for autostereoscopic image selection based on a large number of lenticular elements. An opaque material is applied in the spaces between the lenticular elements. In the WO 99/09750 A1 A stereoscopic viewing system is described which uses a mask which in turn comprises opaque stripes.

The lenticular areas are used to specify directions of light propagation for light coming from the image elements x(i,j), whereby the viewer, from a large number of viewing positions in front of the grid of image elements x(i,j), sees with one eye at least predominantly a first selection from the views A(k) and with the other eye at least predominantly a second selection from the views A(k), thus creating a spatial visual impression for the viewer. At least predominantly means that some of the views can appear in both the first and second selections, but the selections are otherwise different. At least predominantly also means, however, that some of the views can be found exclusively in the first selection and another part of the views can be found exclusively in the second selection, as is the case, for example, with stereoscopic representation based on only two views.

The device also comprises an optical barrier structure arranged in front of the image display unit in the viewer's line of sight to improve the spatial visual impression. Such an optical barrier structure is used, for example, in the DE 10 2007 049 238 A1 The barrier structure is referred to there as an optical element and is arranged between the image display unit and the lenticular disc, i.e. behind it. The barrier structure acts as a filter, it can be designed as a diffusion disc with randomly arranged optical structures, or as a filter array, which contains randomly or regularly arranged optical structures in the form of transparent or opaque filter elements with polygonal outlines. The size and dimensions of the filter elements or the optical structures of the optical element are determined depending on the size of the image elements x(i,j), the optical structures in the case of the DE 10 2007 049 238 A1 serve to reduce visual beat frequencies - moiré effects.

When using lenticular sheets that have been produced according to one of the DE 10 2009 019 762 A1 described methods, i.e. where the separation areas are not exactly linear but have a certain finite extension, disturbing effects occur in the spatial visual impression, since the corresponding concave parts in the separation areas make themselves disturbingly noticeable, the converging lens effect of the neighboring lenticular areas is thereby impaired in the visualization. ization of spatial images is disturbed. An obvious possibility would be to reduce the size of the separation areas. However, this also leads to a reduction in the convex curvature radius of the lenticular areas and even increases the effect of the concave separation areas. Even with lenticular discs made up of real cylindrical lenses, the separation areas - which are never exactly linear - can cause problems, albeit to a lesser extent.

The invention is therefore based on the object of eliminating these disadvantages in the prior art and further improving the spatial visual impression.

This object is achieved in that the barrier structure consists of opaque regions arranged next to one another, in front of or behind the lenticular disc, with the effect of a strip-shaped barrier, wherein each opaque region at least partially covers a separation region.

In contrast to the filter-based devices known in the prior art, i.e. without lenticulars, in which the arrangement of the filter arrays or barriers is always based on the position and size of the image elements x(i,j), the invention proposes barrier structures that are based on the position and size of the separation areas. The opaque areas essentially cover the separation areas and in this way prevent the light propagation scattered by the concave separation areas from having a disturbing effect; they essentially suppress it. While the opaque areas usually used in connection with filter structures for constructing stereoscopic 3D screens have a very wide extent and only let through a small amount of light, the opaque areas here can be selected so that they are not visible at all to the naked eye.

As a rule, each opaque region covers at least partially one separation region. In the simplest case, a uniform width of each strip-shaped opaque region can be selected for differently shaped separation regions, which reduces manufacturing costs. However, the lateral extent of each opaque region in relation to the main direction - i.e. the width of each strip - is preferably determined as a function of its position relative to the separation region to be covered by the opaque region. On the one hand, this serves to better compensate for various concave radii of curvature, but on the other hand, in particular, greater flexibility in the arrangement of the barrier strips, the opaque regions in relation to the separation regions, can be achieved in this way. It is therefore entirely possible to apply the barrier structure directly to the separation regions so that they are not irradiated with light at all or cannot be penetrated by light. However, it is easier to manufacture the barrier on a substantially flat substrate, such as the back of the lenticular sheet or a separate barrier carrier substrate or a cover, such as a cover glass. The dimensions of the barrier structure are then calculated and arranged in such a way that the light coming from the image display unit - transmitted or emitted - falls as exclusively as possible into the convex lenticular areas and is accordingly imaged in the viewing space in the direction of a viewer.

Another effect of applying a barrier structure is that the image contrast is increased. This is due to the fact that the brightness of the screen is reduced by using an opaque barrier structure. In contrast to autostereoscopic arrangements, which are not based on lenticular lens technology but on pure filter technology, the loss of brightness is very low, since the proportion of opaque areas in the total area is comparatively smaller. Another positive effect is that images displayed appear smoother than a display without barrier structures. Since lenticular systems depict the image elements x(i,j) in a coarser and enlarged structure, objects and their edges often appear grid-like, particularly at jump points and with poor channel separation; these structures are smoothed. Finally, the spatial impression or depth effect is also noticeably increased for the human eye, since the integration of this barely perceptible periodic, opaque structure creates a so-called "zero plane".

In a further preferred embodiment of the invention, the period of the lenticular areas is selected depending on a lateral extension of the image elements x(i,j). Additionally or alternatively, the lenticular disc can also be arranged rotated by a predetermined angle to the grid of image elements x(i,j). The barrier strips are then positioned accordingly. The coordination of the lenticular areas with respect to the lateral extension of the image elements x(i,j) enables a further improvement of the spatial representation in that disturbing moiré patterns can be largely eliminated. The cause of such moiré patterns is the superposition of at least two non-congruent or non-identical geometric structures, which leads to visual beat effects, similar to interference patterns, for example. While interference patterns are caused by Light with slightly different wavelengths can cause moiré patterns, the reason for the appearance of moiré patterns lies in different lattice constants or periods for the distance between the image elements x(i,j) or between the lenticular areas. Even with the same lattice constants, a moiré pattern can occur if the two structures are rotated against each other. By adjusting the lattice constant or the angle of rotation of the periodic structure on the lenticular disk - i.e. according to the distance between the lenticular or separation areas and a predetermined angle of rotation - the perceptible moiré stripes can be eliminated by making the distance between the stripes too small or too large for the optimal viewing distance. Alternatively or in addition, a second lenticular disk can also be used to reduce the moiré patterns.

In a further preferred embodiment of the invention, the lenticular sheet has an anti-reflective coating on its side facing the viewer. While conventional image display devices for displaying two-dimensional image content are often provided with an anti-reflective coating, this has not been practiced with lenticular sheets to date, since the brightness is reduced by up to 20% compared to using the lenticular sheet. Nevertheless, devices based on lenticular sheets have strong surface reflections that can prove to be disturbing for a viewer. These disturbing effects are reduced by the anti-reflective coating according to the invention. For example, the front side of the lenticular sheet, i.e. the lenticular structure itself, can be anti-reflective using interference optics and provided with at least one anti-reflective coating. The flat back of the lenticular sheet or the back of a barrier carrier substrate on which the lenticular sheet can be applied can also be mirrored. Preferably, the properties of the anti-reflective coatings are adapted to the differences in the refractive indices of the various media. For example, air has a refractive index of n = 1, so-called float glass has a refractive index of n = 1.52, and the plastic polymethyl methacrylate (PMMA), which is often used to make lenticular panes, has a refractive index of n = 1.49.

Another possibility is to chemically anti-reflective the front side, for example by roughening it with hydrofluoric acid. The surface reflections are then diffusely scattered and reduced for the viewer. However, the surface of the lenticular disc may only be roughened to such an extent that the channel separation is not eliminated or impaired too much. Both variants of anti-reflective coating can of course also be combined with one another and can also be used in lenticular-based imaging systems without the barrier structures according to the invention.

In a further preferred embodiment, the barrier structure is designed as a strip-shaped filter structure, preferably as a photographic film. Thicker barriers are not necessary; rather, for reasons of accuracy, even thinner ones are advantageous. The barrier structure can, for example, be applied to a barrier carrier substrate, onto which the lenticular disc is then applied in order to make the construction as compact as possible. The barrier structure can be applied to the barrier carrier substrate, for example, by cold or hot lamination, digital reproduction, etc. If the barrier structure is designed as a photographic film, the processes described in the unpublished German patent application DE 10 2009 019 761 A1 described method for application. According to the invention, the barrier structure is applied in a first alternative to a barrier carrier substrate between the image display unit and the lenticular sheet. In this case - as mentioned - the lenticular sheet can be applied directly to the barrier carrier substrate, with the barrier structure still located between the lenticular sheet and the barrier carrier substrate.

The barrier structure does not necessarily have to be applied to the surface of the barrier carrier substrate facing the lenticular disc; it can also be arranged on the back of the barrier carrier substrate, in which case the width of the strips must be adjusted slightly in order to cover the separation areas as completely as possible.

The lenticular disc can also be applied to a lenticular carrier substrate, but the lenticular carrier substrate can also be part of the lenticular disc, in which case the unit consisting of the lenticular carrier substrate and the lenticular disc is manufactured as a single piece. The lenticular carrier substrate can also be a very thin layer, which only needs to be thick enough to prevent the lenticular disc from breaking apart at the thinnest points, the low points of the valleys of the separation areas, under normal mechanical stress such as transport, measurement or assembly.

In a further preferred embodiment, the barrier carrier substrate and the lenticular carrier substrate are provided with alignment markings for aligning the lenticular disc and the barrier structure with each other. For this purpose, the two substrates are expediently each made somewhat larger in their geometry than the actually optically effective structures. ren. Markings, such as dots, crosses or lines, are applied to the edge areas of both substrates where there are no optically effective structures. These markings are superimposed as precisely as possible, as a result of which the lenticular pane and barrier structure are aligned with one another. This alignment can be done manually, semi-automatically or fully automatically, for example with the help of control cameras, the naked eye or even a microscope. After adjustment, both substrates can be permanently fixed and connected to one another, for example with adhesives, monomers that harden under UV radiation, etc. The excess substrate with the markings can be mechanically separated from the actual structures, for example by sawing or cutting. In this way, a high level of accuracy in channel separation is achieved.

It is also possible to attach the barrier structures to the front of the lenticular sheet and to a viewer. The simplest option is to provide the separation areas on the lenticular sheet with an opaque cover layer. In a second alternative, according to the invention, a transparent cover is arranged in front of the lenticular sheet from the direction of a viewer. The barrier structure is then applied to this, specifically according to the invention on the side facing away from the viewer. Not according to the invention, the barrier structure can also be applied to the side facing the viewer. The first option is preferable here, as it promises greater protection of the barrier structure against mechanical damage.

The cover can be, for example, a standard cover glass a few millimeters thick made of glass or plastic, but a stretched film can also be used as such a cover. The cover can of course also be provided with a reflection-reducing layer on one or both sides.

In a further embodiment, an optically active liquid is located between the cover and the lenticular disc, the optical properties of which can be manipulated by introducing energy. The optically active liquid can, for example, contain liquid crystals in which the refractive index can be varied by introducing energy into the liquid. For example, by applying a voltage, irradiating the liquid with light of a UV wavelength that is not emitted by the image display unit but which manipulates the corresponding optical property in the liquid, or by heating the liquid, the refractive index of the liquid can be changed in such a way that switching between spatial representation and two-dimensional representation is possible if the refractive index corresponds to the refractive index of the material used for the lenticular disc. In this way, it can be ensured that light emitted by the separation areas is also perceived by a viewer, which - especially in the presence of barrier structures - eliminates the channel separation and thereby forces two-dimensional vision. With an appropriate design of the liquid, it is also possible to increase the effect of the barrier structure, which can be arranged for example, but not exclusively, on the inside of the cover, or to create the barrier effect in the first place. In this case, a separate barrier structure can even be dispensed with. The switching between three-dimensional and two-dimensional representation can of course also be used in lenticular systems without barrier structures.

Also disclosed is a method - not part of the invention - for producing a device for spatial representation, as described above. Such a method includes the following steps, among others: First, a lenticular disc is provided, which is arranged on a lenticular carrier substrate, whereby the lenticular disc and lenticular carrier substrate can be manufactured in one piece - as a rule, the lenticular disc is manufactured from the substrate. The provision here also includes, in particular, the manufacture of the lenticular discs. In addition, a barrier structure is provided on a barrier carrier substrate. Here, too, the provision again includes the manufacture, in particular the application of the barrier structure to the barrier carrier substrate. Finally, an image display unit is also provided.

The barrier structure is then positioned relative to the lenticular disc. The barrier structure and lenticular disc are aligned with each other by marking the lenticular and barrier carrier substrates at predetermined positions and aligning the markings when positioning the barrier structures relative to the lenticular disc. After alignment, the barrier structure and lenticular disc are first fixed to each other and then this assembly is first positioned and then fixed on the image display unit, whereby the substrates may have to be cut to the dimensions of the image display unit beforehand. The barrier structures and lenticular disc can be fixed to each other using adhesive techniques if they are arranged without an air gap. There is often an air gap between the display unit and the assembly consisting of the barrier carrier substrate, barrier structure and lenticular disc, so that these elements must be fixed at a distance from one another.

Instead of marking both substrates and aligning them accordingly, alignment using moiré effects is also possible. To do this, both substrates are positioned on top of each other and light is shone through them from the side of the barrier carrier substrate that is opposite the image display unit. They are then shifted and/or rotated against each other until a pattern to be observed is correctly displayed.

The light does not necessarily have to come from the image display unit, but can also come from another light source. If a bright, particularly white, light source is used, brightness modulations occur, so-called light/dark moiré stripes. The two structures can be adjusted to each other using these moiré stripes. Correct alignment is achieved when either a completely white or transparent area or a largely black or opaque area is visible across the entire surface. This also makes it possible to check whether the period of the lenticular areas matches that of the barrier structure: if the periods differ or if the viewing distance is incorrect, several moiré stripes are constantly visible.

In a special embodiment of this method, both substrates are positioned on the image display unit and illuminated with light emitted by the image display unit. For this purpose, however, a test image is generated that is coordinated with the lenticular disc. This is preferably combined from two views, one of which is an image held in light of a single wavelength, for example red, blue or green, and the other view is exclusively black. This test image is displayed on the image display device - or equivalently on another suitable image generator that is used in production. The lenticular disc and barrier structure are illuminated with the light emitted by the image display unit when displaying the test image. Here, too, alignment is carried out using moiré patterns. Correct alignment is achieved when there are only whole, continuous color moiré stripes. If the two structures are not aligned correctly, this leads to double stripes in the moiré pattern, i.e. to intensity fluctuations within a moiré stripe. In contrast to the method described above, the adjustment does not have to be carried out at the optimal viewing distance from the lenticular screen.

In all three methods - not part of the invention - the alignment can be done by hand and with the naked eye. However, a more precise adjustment can be achieved with the help of a microscopic imaging optics, whereby here too the images are evaluated by an observer and can be rotated or shifted accordingly. However, it is particularly preferred to use image processing and control algorithms in conjunction with a camera that records the observed image, for example a CCD or CMOS camera, so that if the production system is designed accordingly, the alignment of the lenticular disc and the barrier structure to each other can take place automatically.

As already described, lenticular discs can be made, for example, from an optically transparent plastic that hardens under the influence of light, whereby the light is introduced into the plastic in a spatially and/or temporally structured manner, for example with the aid of an exposure mask. This is described, for example, in the unpublished German patent application DE 10 2009 019 762 A1 described. Very good results can be achieved with this method, and it is particularly suitable for the production of small series. However, the production is still comparatively complex, which is why in a special embodiment of the invention the lenticular discs are not produced directly as a so-called positive mold, but rather a negative mold is first produced. This is done by applying a still liquid plastic layer made of a transparent plastic that hardens when energy is applied to a substrate and energy is introduced into the plastic, whereby the amount of energy to be introduced per unit of time is specified in a location- and/or time-differentiated manner, so that after the energy has been introduced, different amounts of hardened and not yet hardened plastic are present at different locations on the surface of the plastic layer, whereby the not yet hardened plastic is removed - for example by washing off. The negative mold therefore has correspondingly shaped concave areas in the places where the lenticular areas are to be found in the positive mold, and correspondingly shaped narrow convex areas in the places where the separation areas are to be found.

This negative mold can then be used to produce positive molds in medium to large quantities. A simple option is to use it as a mold insert for casting or spraying appropriate lenticular discs made of plastic or glass. Another possibility is to use plastic that hardens when exposed to light. To do this, the negative mold is filled with a transparent, still liquid material, this material is allowed to harden completely and then separated from the negative mold, whereby the resulting positive mold corresponds to the lenticular disc.

Within the framework of this so-called "digital reproduction", the production of positive forms or lenticular discs is made considerably easier, since the complex temporally and/or spatially differentiated exposure through masks only needs to be carried out once to produce the negative form. The positive impressions can then be made with this and if a similar material that hardens under the influence of light is used, no spatial or temporal differentiation needs to be taken into account. The energy input can then take place over a large area and with higher energy.

The material used for the positive mold can be liquid glass, for example, or another material that does not bond with the plastic used for the negative mold. In principle, the same plastic can also be used, or another material that would possibly bond with the plastic of the negative mold before or during the curing process if no additional measures are taken. To prevent such a bond, the negative mold is therefore appropriately coated with a separating layer beforehand. This separating layer is ideally thinner than 0.1 mm so that the fine details of the surface profile, which are necessary for the lenticular effect or three-dimensional vision, are not impaired too much by distortion, warping or obscuring.

The separating layer can be applied or deposited onto the surface of the negative mold using vapor deposition or sputtering, for example, from a metal in the appropriate layer thickness. It is also possible to deposit a separating layer from a chemical solution, for example using appropriate dipping baths, from which a corresponding separating layer then remains as a residue from the dipping bath on the surface of the negative mold. Finally, thin films can also be used, for example made of metal or a plastic that meets the requirements.

It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 eine mögliche Ausgestaltung einer Vorrichtung zur räumlichen Darstellung,
• 2 eine zweite Ausgestaltung einer solchen Vorrichtung,
• 3 eine dritte Ausgestaltung einer solchen Vorrichtung,
• 4 eine vierte Ausgestaltung einer solchen Vorrichtung,
• 5 Markierungen auf Substraten zur Ausrichtung der Komponenten zueinander,
• 6 und 7 zwei mögliche Beleuchtungseinstellungen, die bei der Herstellung von Negativformen zur Erzeugung konvexer und konkaver Bereiche verwendet werden können, und
• 8 eine Negativform für die Herstellung einer Lentikularscheibe.

The invention is explained in more detail below, for example with reference to the accompanying drawings, which also disclose features essential to the invention. They show:

• 1 a possible design of a device for spatial representation,
• 2 a second embodiment of such a device,
• 3 a third embodiment of such a device,
• 4 a fourth embodiment of such a device,
• 5 Markings on substrates to align the components to each other,
• 6 and 7 two possible lighting settings that can be used in the production of negative molds to create convex and concave areas, and
• 8 a negative mold for the production of a lenticular disc.

In 1 First, the general structure of a device for spatial representation is shown, with only the most important components that are essential for the spatial representation being shown. The device comprises an image display unit 1 with image elements x(i,j) that are arranged in a grid with rows j and columns i. Information from at least two views A(k) with k=2,...,N and N a natural number can be displayed on the image elements x(i,j). The image display unit 1 is provided with a cover glass 2 that is arranged in front of the image display unit 1 in the direction of a viewer 3. The use of the cover glass 2 is optional. The individual image elements x(i,j) can be designed, for example, as full-color pixels or as red, green and blue subpixels of a grid-shaped liquid crystal display (LC panel). They can either be designed to be independently luminous or can be illuminated from behind by an additional light source (not shown).

A lenticular disc 4 is arranged in front of the image display unit 1 in the viewing direction of the viewer 3. This lenticular disc 4 has lenticular areas 5 and separation areas 6 arranged next to one another, alternating with one another and periodically along the main direction. The main direction can be the vertical, for example, but also a direction tilted to it, provided it is not horizontal. The lenticular areas 5 are used to the light propagation directions for light coming from the image elements x(i,j) are specified, whereby the viewer 3, from a plurality of viewing positions in front of the grid of image elements x(i,j), sees with one eye at least predominantly a first selection from the views A(k) and with the other eye at least predominantly a second selection from the views A(k). This creates a spatial visual impression for the viewer 3.

Finally, the device also comprises an optical barrier structure 7 arranged in the viewing direction of the viewer 3 in front of the image display unit 1 to improve the spatial visual impression. The barrier structure 7 consists of opaque areas arranged next to one another with the effect of a strip-shaped barrier. The opaque areas can be arranged in front of or behind the lenticular disc 4, in the case of the embodiment according to 1 they are arranged behind the lenticular disc 4 in relation to the viewing direction of the viewer 3. The effect of a strip-shaped barrier is most easily achieved when the opaque areas are actually physically designed as strips, but devices are also conceivable in which the effect is only achieved through external influence, for example through a switchable barrier in the form of filters or a liquid. Each opaque area covers at least partially a separation area 6, which achieves the best results in improving the spatial visual impression.

The use of the optical barrier structure 7 prevents disturbing light from being emitted from the separation areas 6 of the lenticular disc 4. While in lenticular discs that are made directly from half-cylindrical lenses or cut out of a correspondingly large substrate, the concave separation areas 6 are only very slightly extended compared to the lenticular areas 5 that have a convex half-cylindrical shape, so that the disturbances to the spatial visual impression are also rather small if no optical barrier structure 7 is used, the improvement in lenticular discs in which the separation areas 6 have a larger extent due to the manufacturing process is clearly noticeable when the optical barrier structures are used. This is the case, for example, with lenticular discs 4 that are manufactured using special exposure techniques from liquid plastic that hardens under the influence of light, either directly as a positive mold or via the intermediate step of a negative mold. In both cases, the extent of the concave separation areas 6 cannot be neglected; the optical barrier structure 7 brings a noticeable improvement here.

The barrier structure 7 is in the case of the 1 shown device is applied to a barrier carrier substrate 8. This is advantageous, for example, when the optical barrier structure is a thin film, for example an exposed film. This can be applied to the barrier carrier substrate 8, for example, using appropriate laminating techniques. There is also an air layer 9 between the barrier carrier substrate 8 and the cover glass 2 of the image display unit 1; this is also optional. In principle, the cover glass 2 can also take on the function of the barrier carrier substrate 8, ie the film with the barrier structure 7 can be applied directly to the cover glass 2, in this way space can be saved if necessary. Since the opaque areas of the barrier structure 7 are also very narrow compared to such opaque areas as are used for filter structures in connection with the spatial representation when no lenticular disk 4 is used, their presence is only slightly noticeable, and is even positive due to a slight increase in contrast.

The opaque areas of the barrier structure 7 can therefore be kept very narrow. The improvement is optimal when the lateral extension of each opaque area in relation to the main direction is determined depending on its position relative to the separation area 6 to be covered by the opaque area. It is important whether the opaque areas are arranged in front of or behind the lenticular disc 4, and their distance from a reference point, for example the lowest point in a valley of a separation area 6, is also important. The extension of the separation areas 6 in the lateral direction also plays a role in determining the width of the opaque strips. The effect is best when the opaque areas, in 1 indicated by the black rectangles, cover the entire concave separation area, possibly even somewhat more, in order to also effectively block light incident obliquely from the image display unit 1.

The lenticular disc 4 can have an anti-reflective coating (not shown) on its side facing the viewer 3. In this way, the surface reflections that otherwise occur and can prove to be disturbing to the viewer can be suppressed. For this purpose, the lenticular disc 4 can be anti-reflective on its front side using interference optics, for example. Such an anti-reflective coating can also be applied to its back side, which is generally flat. Preferably, the optical properties of the anti-reflective coating are adapted to the refractive indices of the immediately adjacent Media to achieve the best effect. Another possibility for anti-reflective coating is chemical anti-reflective coating, for example using hydrofluoric acid or a similarly acting substance. In this case, the anti-reflective layer is intrinsically contained in the lenticular disc 4; it is formed on its surface, for example by roughening it with hydrofluoric acid. However, care must be taken that the channel separation is not reduced too much or even eliminated. The roughening of the surface ensures diffuse scattering of surface reflections, which therefore appear reduced to the viewer 3. Both can of course be combined with one another; for example, a roughened surface can also be provided with an interference-optically anti-reflective layer, which further improves the effect.

The lenticular disc 4 can be applied to a lenticular carrier substrate. This lenticular carrier substrate can also be anti-reflective on its side facing the image display unit 1 as described above, i.e. have an anti-reflective coating. As a rule, the lenticular disc 4 and the lenticular carrier substrate will form a one-piece unit, since the lenticular disc 4 is made from the lenticular carrier substrate.

In the 2 , 3 and 4 Further embodiments of a device for spatial representation are shown. In the device according to the 2 to 4 the lenticular disc 4 is applied directly to the barrier carrier substrate 8 with the barrier structure 7. The dimensions are shown exaggerated here, so the barrier structure 7 is usually only a photographic film of extremely low thickness. The ratios of the lenticular areas 5 to the separation areas 6 are also not shown to scale. They only serve to illustrate the mode of operation. Compared to the design in 1 This has the advantage that the opaque strips of the barrier structure are arranged closer to the valleys of the separation areas 6, so that they can be made narrower overall. The width of the opaque strips is approximately in the order of a few 10 µm, for example 50 µm.

A similar device is in 3 shown, here a barrier structure 10 is arranged on the back, ie the side of the barrier carrier substrate 8 facing away from the viewer 3. Since the opaque areas in this case are arranged somewhat further away from the valleys of the separation areas 6, they must be kept wider than in the two previously described embodiments.

Another arrangement is in 4 shown, here, from the direction of a viewer 3, a transparent cover 11 is arranged in front of the lenticular disk 4, on the side of which facing away from the viewer 3 a barrier structure 12 is applied. For example, glass, transparent plastic or a stable, stretched film can be used as the cover 11; the barrier structure 12 is attached to the underside of the cover 11. Here too, the opaque strips of the barrier can be kept relatively narrow in the range of about 50 µm, since they can be positioned relatively close to the separation areas 6, whose disturbing light scattering they are intended to suppress. In any case, they are hardly perceptible to the naked eye. The cover 11 also offers the advantage that the structure is easy to clean at any time, since the outer surface of the cover 11 facing the viewer 3 can be made smooth. It can also be provided with an appropriate anti-reflective coating on one or both sides. For such a protective function, the use of a cover 11 is also possible without the barrier structure 12 being arranged on its underside; rather, a combination of the pure cover 11 with barrier structures 7 and 10, as described in connection with the 1 to 3 described above are possible.

Regardless of whether or not a barrier structure 12 is arranged on the side of the cover 11 facing away from the viewer, the use of such a cover 11 also offers the possibility of enclosing an optically effective liquid between the lenticular disc 4 and the cover 11. The optical properties of this liquid, for example the refractive index, can then be manipulated by external influences such as applying a voltage, heating or irradiation with light of certain wavelengths, for example with UV light. If the refractive index of the liquid, for example under external influence, corresponds to that of the material used for the lenticular disc 4, the effect of the lenticular disc 4 is canceled and a viewer can perceive a two-dimensional image. To switch to a spatially perceptible representation, the external influence is switched off and the refractive index is then changed accordingly, preferably reduced, so that the spatially imaging properties of the lenticular disc 4 come into play again.

To improve the channel separation and ensure that the barrier structure 7 functions effectively, it is important that the barrier structure and the lenticular disc 4 are correctly positioned and fixed relative to one another so that the barrier structure 7 can develop its optimum effect with respect to the separation areas 6. When producing a device for spatial representation as described above, this step is therefore essential. During production, a lenticular disk 4 is first provided on a lenticular carrier substrate 13, as is a barrier structure 7 on a barrier substrate 8. Furthermore, an image display unit 1 is provided. The image display unit 1 can already be provided with a cover glass 2. The positioning of the barrier structure 7 and the lenticular disk 4 relative to one another can be carried out in various ways.

One possibility is to provide the lenticular carrier substrate 13 with markings 14 and the barrier carrier substrate with markings 15. For this purpose, both substrates 13 and 8 are dimensioned somewhat larger than the optically effective structures on them. This is shown by way of example in 5 The barrier carrier substrate 8 and the lenticular carrier substrate 13 are then aligned with one another by shifting or twisting so that the markings are congruent.

Another possibility is to position the barrier structure 7 and the lenticular disc one above the other - whereby the positioning should be carried out according to the installation to be carried out later, in relation to the arrangement of the barrier structure 7 in front of or behind the lenticular disc 4 with respect to the viewing direction of the viewer 3. From the side of the barrier carrier substrate 8 which is opposite the image display unit 1 - or from the corresponding side of the lenticular carrier substrate 13 or the lenticular disc 4 - both components are illuminated with light, then the barrier structure 7 and the lenticular disc 4 are shifted and/or rotated relative to each other until a pattern to be observed is correctly displayed. Since the structures fit together almost exactly, brightness modulations become visible, so-called light or dark moiré stripes. Using these stripes, both structures can be adjusted to each other. The adjustment is correct if either a completely white or transparent surface or a completely black or opaque surface appears over the entire structure surface. However, this is only the case if the periods of the barrier structure 7 and the separation areas 6 match and the viewing distance is correct.

It is also possible to position the two substrates 8 and 13 or the barrier structure 7 and the lenticular disk 4 on the image display unit 1 and to display a test image that is appropriately matched to the lenticular disk 4 and preferably consists of two views. One of the two views is in a single color, for example red, blue or green, and the other view is exclusively black. Both substrates 13 and 8 are then illuminated with light that is emitted by the image display unit 1 when the test image is displayed. In this case, no light or dark moiré stripes are produced, but rather whole, continuous color moiré stripes. The alignment is correct when there are only whole, continuous color moiré stripes. If the two structures are not aligned correctly, this would lead to a split into two stripes within a moiré stripe, which can be parallel or twisted to one another depending on the angle of rotation. If this is the case, an alignment, i.e. a shift or rotation, must be carried out until both structures are correctly aligned with each other, i.e. only uniform color moiré stripes are visible.

Here, as in the other cases, after the adjustment, both substrates 8 and 13 can be permanently fixed and connected to each other, for example by means of adhesive or monomers that cure under the influence of light.

The alignment can be done with the naked eye or, for example, with the help of a microscope. If the alignment is done with the help of a microscope, the two substrates are preferably illuminated in transmitted light by a white light source. The separation areas 6 and the barrier strips of the barrier structure 7 are usually visible with a magnification of around fifty times. In order to achieve a congruent superposition, at least two full periods should be visible. If the alignment is successful, the opaque strips of the barrier structure 7 must exactly cover the separation areas 6, i.e. not be twisted or parallel to them.

However, it is also possible to carry out the alignment with the aid of markings and/or moiré patterns using a microscope. It is particularly preferred to use a microscopically imaging optic together with a digital camera with a sufficiently high resolution. If the image is shown on a screen, an operator can carry out the alignment more easily than if he or she had to look through the eyepiece the whole time. The camera or the corresponding sensor chip - for example a CCD or a CMOS chip - can also be connected directly to an evaluation unit on which image processing and control algorithms are implemented, with the aid of which the image is evaluated and corresponding control commands are sent for the automatic positioning of the two substrates 8 and 13 against each other. that can be implemented by robotic arms or other positioning tools.

While the production of lenticular discs using classic methods based on diamond tools and nickel molds for replication is only worthwhile for very large quantities, the production of lenticular discs based on plastics that harden when exposed to light and with appropriate exposure is an alternative for small and medium quantities in the range of a few tens to a few hundred lenticular discs. A still liquid plastic layer made of a transparent plastic that hardens when energy is applied is evenly applied to a substrate such as glass or a thick film in a sufficiently thick layer of, for example, 100 µm. Energy is then applied to the plastic, for example by exposure to UV light, whereby the amount of energy to be applied per unit of time is specified in a location and/or time-differentiated manner, for example with the help of one or more exposure masks and illumination with different wavelengths. After the energy has been applied, different amounts of hardened and not yet hardened plastic are present at different locations on the surface of the plastic layer. In the exposed areas, the light-sensitive material on the substrate becomes solid; a light-sensitive monomer, for example, polymerizes and hardens. In the unexposed areas, however, the monomer remains viscous and flexible; in these areas it is removed, for example, by washing out.

By controlling the exposure, the structure to be formed can be designed in such a way that it takes on a desired surface structure, for example a lenticular form. This is exemplified in the 6 and 7 Here, a plastic layer 17 located on a substrate 16 is irradiated with light through an exposure mask 18 spaced apart from the plastic layer 17. While the plastic layer 17 in 6 irradiated with parallel light, it is in the regime which is in 7 shown, irradiated with divergent light. The corresponding hardening areas are shown by the lines within the plastic layer 17. For example, a photographic film of appropriate size can be used as the exposure mask, such as is used in a laser exposure system for producing high-precision circuit boards. It is entirely possible to exchange the masks during the exposure process, to block some areas on the masks, to switch others to permeable, and to change the lighting properties in order to produce the desired lenticular disk 4 with lenticular areas 5 and separation areas 6.

This process is also relatively complex and is only suitable for small series. For series of medium quantities, it is therefore advantageous if the exposure technique is not used to directly produce a positive form, i.e. the lenticular disc 4 itself, but first to produce a negative form 19, as is shown for example in 8 is shown. Using this negative mold, any number of positive molds, ie lenticular discs 4, can then be produced by simply using this negative mold to mold lenticulars.

The negative mold can then be used as a mold insert so that the corresponding lenticular disc 4 is only cast; however, it is also possible to produce the lenticular discs 4 again on the basis of plastics that harden under the influence of light. If material is used which would bond with the negative mold during the production of the lenticular disc or the positive mold, in particular before or during the hardening process, the negative mold is preferably provided with a thin separating layer (not shown). This must be so thin, usually less than 0.1 mm, that the optical properties of the lenticular structure are not impaired.

By means of the methods described above, the devices for spatial representation also described above can be produced inexpensively, which are particularly suitable for medium-sized quantities, since their production does not entail too high costs, and which also provide a very good quality of the spatial visual impression.

list of reference symbols

1

image display unit

2

cover glass

3

viewer

4

lenticular disc

5

lenticular area

6

separation area

7

barrier structure

8

barrier carrier substrate

9

air layer

10

barrier structure

11

cover

12

barrier structure

13

lenticular carrier substrate

14, 15

markings

16

substrate

17

plastic layer

18

exposure mask

19

negative form

Claims (9)

Device for spatial representation, comprising - an image display unit (1) with image elements x(i,j) which are arranged in a grid with rows (j) and columns (i), and on which information from at least two views A(k) with k=2,...,N and N of a natural number can be displayed, - a lenticular disk (4) arranged in front of it in the viewing direction of a viewer (3) with lenticular (5) and separation areas (6) arranged next to one another, alternating with one another and periodically along a main direction, wherein light propagation directions for light coming from the image elements x(i,j) are predetermined by means of the lenticular areas (5), whereby the viewer (3) sees at least predominantly a first selection from the views A(k) with one eye and at least predominantly a second selection from the views A(k) with the other eye from a plurality of viewing positions in front of the grid of image elements x(i,j), thus creating a spatial visual impression for the viewer (3), - an optical barrier structure (7) arranged in front of the image display unit (1) in the viewing direction of the viewer (3) to improve the spatial visual impression, - wherein the barrier structure (7) consists of opaque regions arranged next to one another, in front of or behind the lenticular pane (4) with the effect of a strip-shaped barrier, - wherein each opaque region at least partially covers a separation region (6). - characterized in that - in a first alternative, the barrier structure (7) is applied to a separate barrier carrier substrate (8) located between the image display unit (1) and the lenticular pane (4), or - in a second alternative, from the direction of a viewer (3), a transparent cover (11) is arranged in front of the lenticular pane (4), on the side of which facing away from the viewer (3) the barrier structure (12) is applied. device according to claim 1 , characterized in that the lateral extent of each opaque region with respect to the main direction is determined as a function of its position relative to the separation region (6) to be covered by the opaque region. Device according to one of the Claims 1 or 2 , characterized in that the period of the lenticular regions (5) is selected as a function of a lateral extension of the image elements x(i,j) and/or the lenticular disk (4) is arranged rotated by a predetermined angle to the grid of image elements x(i,j). Device according to one of the Claims 1 until 3 , characterized in that the lenticular disc (4) has an anti-reflective coating on its side facing the viewer (3). Device according to one of the Claims 1 until 4 , characterized in that the barrier structure is designed as a strip-shaped filter structure, preferably as a photographic film. Device according to one of the Claims 1 until 5 , characterized in that the lenticular disc (4) is applied to a lenticular carrier substrate (13), preferably on a lenticular carrier substrate (13) which has an anti-reflection layer on its side facing the image display unit (1). device according to claim 6 , if related back to the first alternative of the claim 1 , characterized in that the barrier carrier substrate (8) and the lenticular carrier substrate (13) are provided with alignment markings (14, 15) for aligning the lenticular disc (4) and the barrier structure (7) with one another. device according to claim 1 , first alternative, characterized in that the lenticular disc (4) is applied to the barrier carrier substrate (8). device according to claim 1 , second alternative, characterized in that an optically active liquid is located between the cover (11) and the lenticular disc (4), the optical properties of which, preferably the refractive index, can be manipulated by energy input, whereby the device can be switched between two-dimensional and spatial representation.

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