DE10358937A1 - Grid panel, for large visible surface areas, is composed of micro-structured diffraction units to give a two-dimensional diffraction of light rays for a variety of design effects - Google Patents

Abstract

The grid is composed of a number of micro-structured diffraction units (12), assembled in a panel (15). They give a two-dimensional diffraction of light rays, through separate bodies on a common surface with gaps between them to act as light scatter centers. The panel surface is covered by the thin-film diffraction elements using lithography.

Description

STATE OF TECHNOLOGY

The The present invention relates to micro and nanostructure technologies and in particular grating arrangements for two-dimensional optical Grid.

dimensional Optical grids are currently essentially only for incorporation into spectrometers for the Area of spectral analysis known. You have real two-dimensional proportions, approximately in the form of a rectangle in the range of up to 20 cm edge length and are made of high quality materials, with the lattice structure has a grating period which is of the same order of magnitude like the associated one Light wavelength lies. The grid is usually created by fine, sequential scribing using diamond tips, around furrows in a suitable solid material into it. There is a periodic arrangement of many rectangular ones Lines of measurements b1 and b2 before. Because with these grids b1 >> b2 applies, they are called one-dimensional.

The Diffraction effects that can be achieved on the grid are known. They are based on the overlay of elementary rays scattered or diffracted (scattering, Reflection and partial transmission) at structural element ends obstacles, hereafter referred to as a stray or mesa diffractive body be done. You can get interesting-looking interference patterns produce.

in the Case of two-dimensional lattice, so if b1 and b2 in the same Magnitude to each other and the order of magnitude the wavelength of light lie, the light is diffracted throughout the half space. this will theoretically for example in Pedrotti, "Optics, an Introduction", Prentice Hall 1996, P. 479 ff., Discussed. A "cruciform two-dimensional figure arises as a diffraction image, instead of a "line-like one-dimensional" figure in use a one-dimensional grid.

Further For example, two-dimensional lattices are known which have arbitrary shapes as diffraction elements instead of the above grid bars (ribs) and furrows (grid trenches) have. A special embodiment, are holograms in which the Grid arrangements are designed so that their Fourier transform a desired one Image with recognition value for the human eye has, see about the holograms on bills.

These Two-dimensional optical gratings are used in particular when They not only parallel line structures as diffraction centers, but one two-dimensional matrix of individual point-like diffraction centers possess, suitably with lithographic processes and appropriate thin-film technology produced.

A disadvantage of these arrangements is that they are produced in the prior art only relatively small-scale, such as in the form of lattice experimentally used in spectroscopes in the range up to about 20 cm by 20 cm, or in the form of holograms in the range up to about 1 × 1 Square meters (1 m ² ). This reduces the aesthetically pleasing diffraction phenomena such as polychrome interference patterns to smaller areas.

task Therefore, it is the object of the present invention to make such arrangements more diffractive Elements, hereafter referred to as "grid arrangements" or "grid", are completely different use.

ADVANTAGES OF INVENTION

Of the The subject matter with the features of claim 1 solves this problem.

In the dependent claims find advantageous developments and improvements of respective subject of the invention.

The present invention is based on the basic knowledge, that a two-dimensional grid with arbitrary arrangements and Patterns of diffraction centers, for example, on lithographic Way made also large area can be.

Of the Term grid is for the purposes of the present invention in a general form using the four types of lattice (phase transmission grating, Phase reflection grating, amplitude transmission grating and amplitude reflection grating), as well as any variations of the lateral extent of the mesa (mountains, Footbridges) and the Mesazwischenräume (Valleys, Furrows, trenches). It is therefore a lattice with laterally varying periods and duty cycle meant.

According to the main aspect In the present invention, a new use of a two-dimensional constructed, optically acting device in the form of a grid disclosed with a plurality of connected to a common base support surface Individual bodies, whereby the single bodies so are designed, arranged and spaced from each other that they as diffraction centers for Light rays act, and wherein the single body structural elements of a Thin-film manufacturing process which is characterized by being a targeted lateral structured arrangement of numerous, diffractive elements represents, and for the design of large areas by large-scale diffraction patterns is used.

Especially therefore advantageous is a use in which this device as a component in a construction activity used for the construction or renovation of building facades, or equipped in the mobile systems with relatively large, visible surfaces according to the invention be, such as the body surfaces of motor vehicles (cars, trucks incl. trailers, buses, trains), or the big ones surfaces of aircraft.

Further It is proposed that this arrangement with grid effect as a module replicable, areal, architecturally usable component with suitable protective cover against the weather manufacture. This can then be used to equip wide façade surfaces. To contains the device according to the invention Connecting elements with which they are compatible with other devices same type edge to be connected to a panel component can. Therefore come, for example. Plug-in detents, other lockable connectors or other known in the art connecting elements such as about latching, in question. A panel to cover an area of one Square meters, for example, consists of a compound Arrangement of a 10 × 10 Matrix of diffraction devices according to the invention, each having a square shape with an edge length of 10 centimeters.

If while still inexpensive Starting materials and raw materials are used, is thus the Way for free a cheap producible mass product that used architecturally advantageous can be used to achieve interesting diffraction patterns or at slow change the viewing angle beautiful Detect color effects over a large area to be able to.

• a) das Material für die Grundträgerfläche vorgewählt ist aus der Gruppe: organische oder anorganische Gläser, Kunststoffe, insbesondere Polymere, Metalle,
• b1) das Material für die Einzelkörper so gewählt ist, dass es allgemein als ätzbare Schicht oder als Opferschicht in einem Ätzprozess selektiv zu einem der vorgewählten Materialien geeignet ist, oder
• b2) das Material für die Einzelkörper so gewählt ist, dass es selektives Wachstum erlaubt, insbesondere durch Anwenden von Galvanik in tiefenlithographisch geformtem Polymethylmethacrylat (PMMA).

According to an advantageous aspect of the present invention, so-called cheap materials are used to make the grids, wherein:

• a) the material for the base support surface is selected from the group: organic or inorganic glasses, plastics, in particular polymers, metals,
• b1) the material for the individual bodies is chosen such that it is generally suitable as an etchable layer or as a sacrificial layer in an etching process selective to one of the preselected materials, or
• b2) the material for the individual bodies is chosen so that it allows selective growth, in particular by applying electroplating in deep lithographic molded polymethyl methacrylate (PMMA).

If the single bodies the device according to the invention in regular Matrix form of parallel rows and parallel columns are arranged, facilitates their production and control.

Advantageous can the materials for the basic support surfaces, on which is a respective plurality of individual bodies, by choice eg. of glass, Plexiglas, plastics, especially polymers, in fact so chosen be that at least the material value of the basic support surface of a Module with one edge length For example, from just under 25 cm is very low.

When Material for the diffractive elements - the Single body - recommends basically Such a material, which has a certain, long-term stable dimensional stability owns and at the same time is well suited to in an etching process if necessary also serve as a sacrificial layer. There are different ones Polymers such as e.g. thermotropic backbone liquid crystalline polymers, and in a special way also commercially available photoresist in question, applied evenly can be used to form a uniform layer thickness.

In order to achieve a high strength of the individual bodies, these locations can previously be made entirely of dielectric materials, for example of suitable silicon-nitrogen compounds, such as Si ₃ N ₄ , or silicon oxides, especially silicon dioxide (SiO ₂ ).

alternative can the material for the single bodies so chosen be that it allows selective growth, in particular by Using electroplating in deep lithographic polymethyl methacrylate - acrylic glass (PMMA).

DRAWINGS

embodiments The invention is illustrated in the drawings and in the following Description closer explained. The mentioned single body serve as a diffraction body in the sense of achieving diffraction effects.

It demonstrate:

1 in a schematic view representation of an overall system according to a preferred embodiment of the present invention comprising a panel for a facade part surface with a plurality of individual modules according to the invention;

2 a schematic representation of the edge coupling devices between two individual modules 1 ;

3 an enlarged view as a section within a grid arrangement of many Individual bodies; and

4 an overview of different types of lattice, which are relevant to the inventive solution.

DESCRIPTION OF THE EMBODIMENTS

In the same reference numerals designate the same or functionally identical Components.

In reference to 1 is a panel according to the invention 15 shown containing a plurality of matrix-like arranged (array-shaped) individual modules 12 , where the outer dimensions of the panel 15 in the case of building facades about 1m to 1 m.

The individual modules 12 For their part, they again contain a large number of optically diffracting single bodies, here as mesa diffraction bodies 31 designated, see 3 Here, for example, here also matrix-like in regular rows and columns on a common support surface 30 can be arranged. The individual bodies are however in 1 not shown for reasons of clarity. How out 1 also visible, are the individual modules 12 of identical shape and interconnected, with more details in 2 are shown.

With further relation to 2 becomes the coupling between individual modules 12 out 1 described in more detail.

Two individual modules 12A and 12B with square contour are edge and corner flush arranged with shock with their respective edge sides together. Advantageously, a snap connection 22a and further snap connection 22b each eccentrically provided to the two individual modules 12A and 12B mechanically connect at two points.

In reference to 3 is an enlarged view as a section within a grid arrangement 12 from many individual bodies 31 shown.

The single bodies 31 are here only exemplarily designed as a uniform cuboid on the base support surface 30 shown evenly arranged.

The edge dimensions of these individual bodies, the diffraction body 31 and their distances from each other can be varied in a wide range. This applies to location-dependent variations in the same single module, within a panel, as well as for variations from overall system to overall system. In this case, the edge lengths of the mesa diffraction bodies 31 and whose distances in at least one direction preferably vary within a range determined by the diffraction condition, edge length on the order of the wavelength of the light, for example between 200 and 2400 nanometers. It should be remembered that, if necessary, the refractive index of a lattice top layer must be taken into account. The exact shape and arrangement of the mesa diffraction bodies 31 should also be of the future intended use of the individual modules 12 or the panels 15 be made dependent. This is essential especially for holograms.

in the The following are basic guidelines for the manufacture of a diffractive body device according to the invention given. First It should be noted that the basis of the production usual, in The prior art known thin film manufacturing processes are where thin ones Layers by vapor deposition, spin coating, dip coating, sputtering, Galvanizing, etc. are produced, and by further lithographic Manufacturing processes then small-scale and usually in plane-parallel construction to the previously applied layers can be structured depending on how big the Structures in the photomask are. In that regard is completely on textbooks referenced, which describe the aforementioned techniques.

Production method:

in the The following are basic guidelines for the manufacture of a diffractive body device according to the invention given. First It should be noted that the basis of the production usual, in The prior art known thin film manufacturing processes are where thin ones Layers by vapor deposition, spin coating, dip coating, sputtering, Galvanizing, etc. are produced, and by further lithographic or photolithographic manufacturing processes then small-scale and mostly in surface micromechanical plane-parallel structure to the previously applied layers structured can be depending on how big the Structures in the photomask are. In that regard is completely on textbooks referenced, which describe the aforementioned techniques.

• I. Für eine Verwendung als Fassadenelement und zur Herstellung von Einzelmodulen quadratischer Form mit einer Kantenlänge von knapp 12,5 cm wird als Grundträgerfläche 30 eine dünne Glasscheibe als Glassubstrat mit diesen Abmessungen verwendet. Anstelle von anorganischem Glas kann auch ein anderes transparentes Material, organische Gläser (z.B. Plexiglas), transparente Kunststoffe bzw. Polymere evtl. unter Beimischung einer Abtönfarbe verwendet werden.
• IIa). In einem zweiten Schritt erfolgt das Aufbringen einer ätzbaren Gitterschicht – oder im Falle von gewollten Unterätzungen, um eine gewisse Beweglichkeit der Einzelkörper zu er zielen, einer Opferschicht – mit definierter Dicke, die im wesentlichen durch die Höhe der in 3 dargestellten Beugungskörper – diffraktiven Elemente – 31 vorgegeben ist. Die Höhe der Opferschicht sollte wenigstens so hoch sein, dass ein gut sichtbarer Beugungseffekt entstehen kann, etwa eine Höhe von mindestens 50 Nanometern, oder mindestens circa einem Viertel der Wellenlänge.

Manufacturing method based on surface micromechanics:
In the following, the most important manufacturing characteristics are exemplary for the in 3 embodiment shown explains as follows:

• I. For use as a facade element and for the production of single modules square shape with an edge length of almost 12.5 cm is used as a basic support surface 30 a thin glass plate as a glass substrate with these dimensions used. Instead of inorganic glass, it is also possible to use another transparent material, organic glasses (eg Plexiglas), transparent plastics or polymers possibly with the addition of a tinting ink.
• IIa). In a second step, the application of an etchable grid layer - or in the case of intentional undercuts, to a certain mobility of the individual body to he aim, a sacrificial layer - with a defined thickness, which is essentially determined by the height of in 3 illustrated diffraction bodies - diffractive elements - 31 is predetermined. The height of the sacrificial layer should be at least so high that a highly visible diffraction effect can occur, such as a height of at least 50 nanometers, or at least about a quarter of the wavelength.

Of the For the sake of simplicity, the following will not distinguish between etchable Grid layer and sacrificial layer distinguished, both should be under the term "sacrificial layer".

This sacrificial layer is said to diffract 31 form for the grid arrangements. This applies to the four types of gratings: amplitude reflection gratings, amplitude transmission gratings, phase reflection gratings, phase transmission gratings. At the locations of the individual bodies, the sacrificial layer must subsequently be preserved, and in all other places the sacrificial layer is subsequently etched away to allow diffraction. In order to ensure a high degree of transparency, for example if the grating is to be used in transmitted light, the sacrificial layer is preferably removed at these points except for the glass substrate. This succeeds perfectly with today's technological processes. It should be noted that, for example, the base plate can be made of inorganic glasses.

When Materials of the sacrificial layer come primarily such materials in question, facing each other all other materials used can be selectively etched and weathered, moisture and temperature differences are relatively insensitive, a sufficient have mechanical strength and no appreciable plastic Flow have (without hysteresis). For example, come materials, such as Polymethyl methacrylate, silica or a UV photoresist in question, as long as it can be applied with a defined thickness.

• II.b). Alternativ zu IIa) wird eine Variante angegeben, welche Beugungskörper 31 mit erhöhter Festigkeit liefert. Im wesentlichen wird dabei der Prozessschritt IIa) wie folgt ersetzt. Dazu wird ein tiefenlithographiefähiger Photolack (z.B. PMMA) aufgebracht, in welchem die Formen aller Einzelkörper 31 durch Belichten und Entwickeln als Negativ definiert werden. Durch selektives Auffüllen beispielsweise durch galvanische Prozesse, werden stabile Beugungskörper etwa als Quader oder Zylinderformen definiert. Nachfolgend werden die weiter unten folgenden Prozessschritte IV, V, und VI angewandt, wobei der verbleibende Photolack (Opferschicht) nasschemisch entfernt wird.
• III. In einem weiteren Schritt werden vorzugsweise am Rand eines jeden Einzelmoduls umlaufende Abstandhalter aufgebracht, beispielsweise aus dem selben Material wie die vorgenannte Opferschicht, um in einem weiteren (späteren) Schritt das Anbringen einer äußeren Schutzschicht bewirken zu können, die sich flächig über die gesamte Modulfläche erstreckt, um eine hermetische Versiegelung gegen Staub und Feuchtigkeit sowie einen Spannungsschutz zu realisieren. Diese Schutzschicht kann beispielsweise auf die vorgenannten Abstandhalter, die besonders bevorzugt als umlaufende Randbegrenzung vorliegt, durch Kleben aufgebracht werden.
• IV. In einem nächsten Schritt wird die vertikale Strukturierung vorgenommen, indem ein Ätzvorgang senkrecht zur Grundplatte 30 hin vorgenommen wird. Anschließend werden selektiv die oben beschriebenen Teile der Opferschicht entfernt.

As an example, the material class of the thermotropic main chain liquid crystalline polymers may be mentioned. On the one hand, this class of materials can be well-solved with certain organic solvents (sacrificial layer property) and, on the other hand, also meets relatively high mechanical stability criteria.

• II.b). Alternative to IIa), a variant is given which diffraction bodies 31 delivers with increased strength. Essentially, the process step IIa) is replaced as follows. For this purpose, a deep lithography photoresist (eg PMMA) is applied, in which the forms of all individual bodies 31 be defined as negative by exposure and development. By selective filling, for example, by galvanic processes, stable diffraction bodies are defined approximately as cuboids or cylindrical shapes. Subsequently, the process steps IV, V, and VI below are applied, whereby the remaining photoresist (sacrificial layer) is removed wet-chemically.
• III. In a further step, peripheral spacers are preferably applied to the edge of each individual module, for example of the same material as the aforementioned sacrificial layer, in order to be able to attach an outer protective layer in a further (later) step, which extends over the entire module surface to provide a hermetic seal against dust and moisture as well as voltage protection. This protective layer can be applied by gluing, for example, to the abovementioned spacers, which are particularly preferably in the form of peripheral boundary.
• IV. In a next step, the vertical structuring is done by etching perpendicular to the base plate 30 is made. Subsequently, the above-described parts of the sacrificial layer are selectively removed.

optional may be later Using the thus manufactured module still a hermetic sealing paint over the entire edge area of the module are brought, so that the module interior maintains a long term stable, weather resistant condition.

Then the modules thus produced are put together as shown in FIG 2 is sketched until a panel is formed with the desired size. For example, with a single module size of 12.5 cm × 12.5 cm, a grid of 8 × 8 individual modules can be plugged together to obtain a coherent panel. The individual modules 12 have for this purpose also advantageously pluggable snap-in connections 22A and B at the remaining edges, which in 2 not shown. The latching connections in the transverse direction may also be of another type - for example an L-shaped detent - compared to the type of the longitudinal direction as in FIG 2 shown to simplify the mating.

In an optional way, this entire panel can 15 now on another carrier 15 on be brought, for which, for example, another glass in question. This would be particularly recommended if increased mechanical stability of the entire panel should be required.

The Diffraction body arrangement according to the invention can, so much is the expert in the field of thin film production and microstructuring be made in many different ways become. Characteristic of the production process according to the invention is therefore only the use of such materials, which is a reasonable Price-performance ratio for one large area use in the window or facade area, and the adaptation of the lithographic process to the relatively small dimensions of the diffraction bodies.

In general and especially in the case of a desired hologram effect, a mathematical optimization is specifically recommended for this desired application. In this optimization, the following aspects should be given special consideration:
The orientation of the facade in terms of the direction and location of the building in terms of the latitude and the angular areas under which the building is seen in most cases by passers-by. These influencing factors can be assigned a quantitative weighting in order to achieve a desired optimum. A slight, outside temperature-induced variation of the diffraction body curvatures still causes periodic color shifts over longer periods of time.

Even though the present invention based on preferred embodiments As described above, it is not limited thereto on diverse Modifiable way.

For example can the sizing of the area the individual modules are adapted to manufacturing plants that already exist and previously for the production of IC components, hard disks in the computer field, etc, were used.

It It should be noted that grids are divided into two classes leave: reflection grille and transmission grating. In both cases will divided further, depending on whether phase differences or amplitude differences are involved.

Thus, there are phase transmission gratings, phase reflection gratings, amplitude transmission gratings and amplitude reflection gratings. This is in 4 shown. By way of example and in order to arouse increased clarity of the representation of the actual invention, the text in most cases was based on the amplitude reflection grating. However, it will not be difficult for a person skilled in the art to correspondingly transfer the actual inventive situation to the other types of lattice mentioned.

In this context, the word "reflection" is not necessarily meant for specular elements, indicating that the diffraction pattern is observed on the same side of the grating on which the light is incident (cf. 4 ). The elements must only have scattering character. In transmission grids, the diffraction pattern is observed on the other side of the grating from which the light is incident ( 4 ).

Amplitude transmission gratings have opaque elements 97 and translucent elements 96 on. Amplitude reflection gratings have light-scattering (in special cases reflective) elements 94 and translucent (or light absorbing) elements 95 on. In one embodiment, these may be mesa (ribs, lands) and mesa spaces (clefts, furrows). Phase transmission gratings have at least two different light-transmissive elements, which differ in that a phase shift of the light arises between adjacent elements. In one embodiment, these may be glass mesa 92 and fluid mesa spaces 93 be. Phase reflection gratings have at least two different light-scattering or light-reflecting elements, which differ in that a phase shift of the light arises between adjacent elements. In one embodiment, the mesa 99 and the soils of the mesas 98 Made of surfaces mirrored glass. The phase difference results solely from the height difference between mesas and mesa, the wavelength, the angles of incidence and reflection, and the refractive index of the fluid in the mesas. Finally, the features of the subclaims can be combined substantially freely with one another and not by the order given in the claims, provided that they are independent of each other.

The cross-sectional shape of the mesa diffraction bodies 31 can be varied in a wide range, as long as the required diffraction-relevant size is present. In this case, the edge lengths of the mesa diffraction bodies 31 and whose distances in at least one direction preferably vary within a range determined by the diffraction condition, edge length on the order of the wavelength, for example between 200 and 2400 nanometers. The exact shape and arrangement of the mesa diffraction bodies 31 should also be of the future intended use of the individual modules 12 or the panels 15 be made dependent. This is essential especially for holograms.

If the base support surface should not be flat, but should have an arbitrarily curved shape, for example in order to adapt it to the individual shape of car body parts, it may be expedient to use the inventive diffraction device 12 to produce on a thickness-adapted film as a basic carrier 30 to ensure the required flexibility. Individually curved modules can then be incorporated at a suitable location in the manufacturing process in the bodywork processing, especially during painting.

Claims (6)

Use of a two-dimensional optical grating device ( 12 ) having a plurality of with a common base support surface ( 30 ) connected individual bodies ( 31 ), wherein the individual bodies are designed, arranged and spaced from each other so that they act as diffraction centers for light rays, and wherein the single bodies are structural elements from a thin film manufacturing process, characterized in that the grating device ( 12 ) represents a deliberately laterally structured arrangement of numerous diffractive elements and is used for the design of large areas by large-area diffraction patterns. Use according to claim 1, wherein the panel ( 15 ) comprising a plurality of devices ( 12 ) are used according to claim 1. Use according to claim 1 or 2, wherein the grating device ( 12 ) or a panel ( 15 ) is used as a component in a construction activity for the construction or renovation of building facades. Use of a grating device ( 12 ) according to claim 1 or 2 for the design of surfaces, in particular of body parts of mobile systems, including their windows. Use according to claim 1 or 2, wherein grid arrangements ( 12 ) consisting of cheap materials. Use according to the preceding claim, wherein: a) the material for the basic support surface ( 30 ) is selected from the group: organic or inorganic glasses, plastics, in particular polymers, metals, b1) the material for the individual bodies ( 31 ) is selected such that it is etchable layer or as a sacrificial layer in an etching process selectively to one of the preselected materials, or b2) the material for the single body ( 31 ) is selected to allow selective growth, in particular by employing electroplating in deep lithographic polymethyl methacrylate (PMMA).