WO2005059622A1

WO2005059622A1 - Diffraction film having a 2-dimensional lattice arrangement

Info

Publication number: WO2005059622A1
Application number: PCT/DE2004/002721
Authority: WO
Inventors: Hartmut Hillmer; Jürgen Schmid; Ingo Stadler
Original assignee: Universität Kassel
Priority date: 2003-12-15
Filing date: 2004-12-13
Publication date: 2005-06-30
Also published as: DE10358812A1; DE10358812B4

Abstract

The invention relates to a diffraction device for the two dimensional diffraction of light beams. Said device comprises a plurality of individual bodies (31) which are connected to a common base support surface (30). The individual bodies are arranged in such a manner at a distance from each other that they act as diffraction centres for the light beams. In order to produce said devices in an economical manner whose size can be measured in square decimetres and above a) the material for the base support surface (30) is selected from a group comprising organic or inorganic glass, plastics, in particular polymers and metals, b1) the material for the individual body (31) is selected in such a manner that it can be used selectively as a sacrificial layer in a corroding process for one of the preselected materials or b2) the material for the individual body (31) is selected in such a manner that it allows selective growth, in particular, by using galvanic deep lithographically formed polymethylmethacrylate (PMMA). Said mesa-diffraction bodies are displaced electrostatically, in order to modify in a location dependent manner, the active lattice constant and in order to obtain variable colouring effects.

Description

Diffraction foil with 2-dimensional grating arrangement

STATE OF THE ART

The present invention relates to micro- and nanostructure technologies and, in particular, to grating arrangements for two-dimensional optical grids. In particular, it relates to a device according to the preamble of claim 1.

One-dimensional optical gratings are currently essentially only known for installation in spectrometers for the field of spectral analysis. They have real two-dimensional dimensions, for example in the form of a rectangle in the range of up to 20 cm edge length, and consist of high-quality materials, the lattice structure having a lattice period which is of the same order of magnitude as the light wavelength. The grid is created e.g. through fine, sequential scribing using diamond tips to generate furrows in a suitable solid material. There is a periodic arrangement of many rectangular lines of dimensions bl and b2. Since bl >> b2 applies to these grids, they are called one-dimensional.

The diffraction effects that can be achieved on the grating are known. They are based on the superposition of elementary rays caused by diffraction (scattering, reflection and partial

Transmission) on structural elements, which are also referred to below as scattering or mesa diffraction bodies. You can create interesting looking interference patterns. In the case of two-dimensional gratings, that is if bl and b2 are in the same order of magnitude and the order of magnitude of the light wavelength, the light is diffracted into the entire half-space. This is theoretically discussed, for example, in Pedroti, "Optics, an introduction", Prentice Hall 1996, pp. 479 ff. A "cross-like two-dimensional" figure is created as a diffraction image instead of a "line-like one-dimensional" figure when using a one-dimensional grating ,

Furthermore, two-dimensional gratings are known which have arbitrary shapes as diffraction elements instead of the above-mentioned lattice webs (ribs) and grooves (lattice trenches). A special embodiment are holograms in which the grating arrangements are designed in such a way that their Fourier transformation has a desired image with recognition value for the human eye, see for example the holograms on banknotes.

Unfortunately, such or similar diffraction effects cannot be varied, that is to say with the same grating only one interference pattern or, in the case of holograms, a small, fixed number (usually two) of diffraction images can be generated.

It is therefore an object of the present invention to provide a device according to the preamble of claim 1, which can vary diffraction patterns.

ADVANTAGES OF THE INVENTION

The object with the features of claim 1 solves this problem.

Advantageous further developments and improvements of the respective subject of the invention can be found in the subclaims. The present invention is based on the fundamental finding that a two-dimensional grating with any arrangements and patterns of diffraction centers can also be produced by lithography in such a way that the individual bodies can be moved partially, in groups or completely by a suitable actuation mechanism around the Vary grid spacing to vary uniformly or locally on the grid arrangement.

The term grating is used for the purposes of the present invention in a general form which includes the four grating types (phase transmission grating, phase reflection grating, amplitude transmission grating and amplitude reflection grating), as well as any variations in the lateral extent of the mesa (mountains, ridges) and the mesa intermediate. areas (valleys, furrows, ditches). What is meant is a grid with a period and duty cycle that varies laterally. In accordance with the most general aspect of the present invention, a diffraction device is therefore disclosed as a grating arrangement for the two-dimensional diffraction of light beams, with a plurality of individual bodies connected to a common base support surface, the individual bodies being arranged and spaced apart from one another such that they are in a two-dimensional grating arrangement in each case act as diffraction centers for the light beams, and the individual bodies are structural elements from a thin-film production process, wherein according to the invention a single element, as a more or less predominant part of an individual body, is mounted so as to be movable relative to the base support surface for an actuation mechanism acting jointly on an individual element or on groups of individual elements is to vary the effective grid spacing between adjacent individual bodies or individual elements or their duty cycle. The individual bodies are, for example, individual mesa. According to the aforementioned aspect of the present invention, the individual bodies acting as diffraction centers or each part of a “single element” are movably mounted. For example, a single body in the form of a single metal element is movably mounted relative to the base support surface in order to increase the effective grating spacing between adjacent individual bodies Varying color effects can thus be achieved for a fixed observation point. “Variation of the effective grating distance” is understood in the following: on the one hand the variation of the distances between the individual mesa (single mesa elements) and on the other hand the diffraction-relevant dimension of the mesa and the mesazvi. the spaces between. All lateral dimensions can thus be varied (actuated), for example the grating period and also the duty cycle.

If values according to the following measures: a) the material for the base support surface is selected from the group: organic or inorganic glasses, plastics, in particular polymers, metals, bl) the material for the individual bodies is selected so that it is used as a sacrificial layer in an etching process is selectively suitable for one of the preselected materials, or b2) the material for the individual bodies is selected such that it allows selective growth, in particular by applying electroplating in deeply lithographically shaped polymethyl methacrylate (PMMA), then the diffraction devices are also achieved in large quantities To create a scale on large areas in the range of decimeters or meters in order to be able to display the diffraction patterns over a large area. It also discloses a way in which such an optical grating can be manufactured inexpensively. This clears the way for an inexpensive mass product that can be used as a decorative object for building windows or directly irradiated can be used by spotlights or the sun to achieve interesting diffraction patterns or to be able to recognize beautiful color effects over a large area with a slow change in the viewing angle.

It is also proposed to manufacture the grid arrangement as a modular, replicable, areal, architecturally usable component with a suitable protective cover against the weather. This allows large facade surfaces to be populated. For this purpose, the device according to the invention contains connecting elements with which it can be connected at the edge to other devices of the same type. For example, catches, other lockable plug connections or other connecting elements known in the prior art, such as latching, come into question.

If the device according to the invention contains plug-in connecting elements, the connecting elements also containing an electrical plug connection between devices of the same type in addition to the mechanical connection, result

Advantages of easy handling, electrical control also in the variants described below, in which the individual bodies can be moved electrically.

If the individual bodies of the device according to the invention are arranged in a regular matrix form consisting of parallel rows and parallel columns, production and control are facilitated.

If the device according to the invention contains one or more actuation mechanisms with a predetermined number of comb actuators, then with a controlled movement of a comb a correspondingly large number of individual bodies or individual elements can be moved uniformly, uniformly and precisely. This movement can then be exploited to be the most effective To vary the grid spacing between adjacent individual bodies or individual elements in a targeted manner.

If the actuation mechanism is based on electrostatic forces, there are favorable electrical properties with low holding currents.

If the device according to the invention contains an actuation mechanism for the lateral displacement of individual bodies or individual elements or groups thereof, the effective grid spacing between adjacent individual elements can be varied in a targeted manner in a first direction.

Correspondingly, a further mechanism can be provided in order to specifically vary the distances in a second direction, preferably perpendicular to the first.

If the individual elements have a flat shape, then by changing the orientation of the "surface normals" of the individual elements with respect to the direction of view or the direction of the incident radiation, a change in the effective grid spacing can be effected, as a result of which beautiful color effects can be achieved.

If the individual elements are flat and firmly connected to the base support surface or a comb actuator

Holding elements are stored, the storage allowing movement of the individual elements by means of an electrostatic actuation mechanism, then the desired change in the effective lattice spacing results from actuation, which can also be superimposed with the aforementioned changes by a corresponding combination of the aforementioned comb actuators.

According to the invention, a so-called panel contains one device or a plurality of such devices described above. Such a panel preferably contains a power supply connection and a device for receiving control commands from a control device.

This creates a system for the design of building facades, walls, body parts of mobile systems, etc., which contains one or more panels, a control unit for controlling the effective grid spacing between adjacent individual bodies of the panel, and a device for transmitting control signals the panel. This means, for example, that an entire high-rise facade can be used specifically to create color effects or diffraction pattern effects.

A system is advantageous in which the control electronics, which contains the logic as to which individual elements are to be controlled and how, are provided centrally in a dedicated, remote control unit, from which an addressing network for controlling the individual individual elements or The module is based on the fact that largely in the form of printed lines, the areal modules are already integrated during their manufacture. This eliminates the need to implement expensive silicon-based chip technology in the facade element itself. Furthermore, much cheaper materials than high-purity silicon are used to produce the diffraction arrangements themselves. This results in production costs that are at least in the same order of magnitude as other, conventional facade elements.

As can be seen from the foregoing, the materials for the base support surfaces on which a respective large number of individual bodies stand and which carry the individual elements can actually be selected by choosing, for example, glass, plexiglass, plastics, in particular polymers, such that at least the material value of the base surface of a module with a

Edge length, for example, of just under 25 cm is very low.

As material for the individual elements and the holding elements for the individual individual elements, it is generally advisable to use a material that has a certain, long-term stable dimensional stability and is at the same time well suited to serve as a sacrificial layer in an etching process. Various polymers such as thermotropic main chain liquid crystalline polymers and, in a special way, commercially available photoresist, which can be applied evenly in order to form a uniform layer thickness, come into question. In order to achieve a high strength of the holding blocks, these locations can previously be manufactured entirely from dielectric materials, for example from suitable silicon nitrides, such as Si ₃ N ₄ , or silicon oxides, especially silicon dioxide (Si0 ₂ ).

Alternatively, the material for the holding elements can be selected so that it allows selective growth, in particular by applying electroplating in deeply lithographically shaped polymethyl methacrylate (PMMA)

If, in a special case, the individual elements are arranged in a regular matrix form consisting of parallel rows and parallel columns, there is a clear production method, since the structures for the production are relatively easy to replicate, which is particularly important for all those embodiments in which electrical supply lines are individual Individual elements (see below) or for combined groups of individual elements must be integrated during the lithographic manufacturing process.

In particular, there is an electrostatic actuation, which will be discussed further below, a magnetic actuation Vation, a piezoelectric and a thermal actuation in question.

If the actuation mechanism for the individual elements - as is preferred here - is based on electrostatic forces and is used for a lateral movement of the individual bodies essentially parallel to the support surface, a comb actuator is preferred here, the basic structure and mode of operation of which is published, for example, in: Micromachined Polysilicon Microscanners for Barcode Readers, IEEE Photonics Technology Letters, Vol. 8, No.12, Dec. 196, pages 1707 to 1709, which is to serve as a source of disclosure for this purpose for the essential technical features of comb actuators. It is clear that the erection process shown there as a result of the comb actuation is not necessary for a purely lateral displacement of the individual bodies, but can nevertheless be used to move the aforementioned flat individual body from a rest position in a quasi-rotating manner in order to also effectively remove the grid spacing to change.

Furthermore, a large number of individual bodies can advantageously be moved with a single comb, all of which then sit together on the moving part of the comb.

Alternatively, a first electrode is expediently assigned to an individual element and a second electrode to the base support surface. The second electrode can optionally also be present for several or all individual elements as a flat electrode on the base support surface and firmly connected to it.

In this exemplary embodiment, electrical supply and contacting of the electrodes of individual individual bodies or of groups of individual bodies is preferred, which leads to one of the outer edges of the device, in order to to be able to be forwarded from there. In particular, the electrical supply lines for computer-controlled addressing and actuation of the movement of the individual bodies and thus the movement of the individual elements via the electrode pairs are provided as planar lines (integrated conductor tracks), which is easy to handle when laying the facade components according to the present invention and is simplified Maintenance and reduced susceptibility to corrosion and other harmful environmental effects.

In addition to the mechanical coupling members, the above-mentioned connecting elements advantageously also contain the corresponding electrical plug connections, so that both the mechanical and the electrical connection are ensured by a single plugging process. This enables simple electrical connections to a control device which is used jointly for a large number of individual modules according to the invention which are plugged together to control the individual elements or small groups of individual elements.

If, in a further advantageous manner, a single element is connected to the holding element via, for example, an elongated bridge element having a predetermined bending stiffness, then there is a simple dimensioning and design of the individual layer thicknesses and lengths due to the dependence between the force field and the tilting angle of the individual element achieved by the simple lever law and Relatively simple bending mechanism of a "beam" clamped at a free end. The complex deformation of the connecting bridge (English cantilever, bending beam) is shown in Fig. 3. The movement of the mirror plane, quasi tilting or pivoting movement of the mirror plane can relate to an axis which is perpendicular to the alignment of the bridge element and at the same time runs parallel to the base support surface. For reasons of better comprehensibility, a tilting or swiveling movement is assumed in the following, and referenced to the associated axis. This embodiment is easy to manufacture, since the bridge element can again be a structural element of a layer. There are

Depending on the pre-tilt, tilt angle θ is possible between approx. -80 ° and + 30 °, at about 30 ° pre-tilt, and if an actuation voltage can pull the individual element up to 80 °, where θ = 0 ° corresponds to the horizontal when installed.

If, in a further advantageous manner, the individual element is fastened to two elongate bridge elements which, in a substantially parallel direction, form a pivot axis for the region of the individual element and start on opposite sides of the individual element, and the torsional rigidity of the bridge elements about their pivot axis thus increases If the electrostatic forces between the electrodes are adjusted so that a pivoting movement of the individual body with a specifically adjustable deflection angle relative to the base support surface can be carried out, then with appropriate charging of the electrodes, the individual element tilts about the pivot axis by attraction or repulsion, perpendicular to the pivot axis of the example mentioned above with a bridge element. The easiest way to set the tilt angle φ is between approx. -80 ° and + 80 ° without tilting, if the actuation voltage can pull the individual element up to +/- 80 ° during electrostatic actuation. The angle φ = 0 ° corresponds to the horizontal. This enables very wide ranges of the tilt angle.

The main advantage of electrostatic actuation is that only good holding currents are required with good electrical insulation.

If, in a further preferred manner, a single element is gimbal-supported by a further pair of bridge elements, which within the pivoted according to the preceding claim Reichs is provided, the full functionality of the angle adjustment results for a change in the effective grid spacing in the x and y direction. The angles θ and φ can be set almost independently. This means that the mirror itself can be easily adjusted independently or depending on the course of the day in order to get the correct mirror position for the various applications. This requires a control program implemented in the control unit, which has the appropriate tracking logic and driver programs for the overall system to be used. The overall system can consist, for example, of a large number of 2048 individual modules, each divided into 4 x 4, i.e. 16 groups, each occupying a facade area with an area of 1 square meter, with a total of 128 such partial areas being included in the overall system.

If, as is also preferred, the individual element is oriented to the pivot axis such that a pivot axis divides the individual element off-center, a further parameter for optimizing the tilt angle has been found, the short side being used, for example, as a side for attraction or repulsion on electrodes can. A short lever then means a wide range of tilting movement, but accordingly requires high force.

According to a particular aspect of the present invention, a use of the two-dimensionally constructed, optically acting device according to the invention in the form of a grating is disclosed, in which it is used to design large areas by large-area diffraction patterns.

A use in which this device is used as a component in a construction activity for the construction or renovation of building facades, or in which mobile systems with relatively large, visible surfaces can be used according to the invention, for example the body surfaces of motor vehicles such as trains, buses, trams, passenger cars, or the large surfaces of trucks and their trailers, or the body surfaces of airplanes.

DRAWINGS

Examples of the invention are shown in the drawings and explained in more detail in the description below. The individual bodies mentioned serve as mesa diffraction bodies in the sense of achieving diffraction effects.

Show it:

1 shows a schematic view of an overall system according to a preferred exemplary embodiment of the present invention, comprising a panel for a facade partial area with a large number of individual modules according to the invention and the associated control devices;

FIG. 2 shows a schematic illustration of the edge-side coupling devices between two individual modules 12 from FIG. 1;

3 shows a schematic cross-sectional representation of an individual body with a mesa diffraction body, as is often present repeatedly on an individual module 12 in FIG. 1, according to a first exemplary embodiment of the present invention;

4 shows a schematic top view of the single body shown in FIG. 3;

5 shows a schematic cross-sectional representation of an individual body, as it is repeated many times in an individual module

12 from Fig.l occurs in a preferred invention Variant in which the mesa diffraction body is suspended on two sides;

6 shows a plan view of the individual body according to FIG. 5;

FIG. 7 in a schematic plan view representation further details for the relative arrangement and orientation between the mesa diffraction body and the bridge element according to variants A), B) and C) according to the exemplary embodiment from FIGS. 5 and 6;

8 shows a schematic top view of an individual body of a preferred, further embodiment of the present invention, in which a mesa diffraction body is mounted in a cardanic manner;

9A is a sketchy representation of a further development of the gimbal-mounted individual body according to FIG. 8 with a non-rectangular shape;

10 shows a schematic plan view (detail) of several rectangular mesa diffraction bodies in a 2-row grating arrangement

11 shows a schematic plan view (detail) of several rectangular mesa diffraction bodies in a 3-row grating arrangement,

12 shows a schematic plan view (detail) of a plurality of rectangular mesa diffraction bodies in a 3-row grating arrangement (grating spacing preset only in the x direction, the unactuated starting position being shown above, one of several realizable ones being activated in the middle Positions of a middle section shows, with nine mesa diffraction bodies are laterally displaced.

13 shows a schematic plan view (detail) of a grating arrangement with several rectangular and line-shaped diffraction bodies of different sizes.

14 shows an overview of various types of grids which are relevant to the solution according to the invention.

DESCRIPTION OF THE EMBODIMENTS

In the figures, identical reference symbols designate identical or functionally identical components.

With reference to FIG. 1, a panel 15 according to the invention is shown, comprising a multiplicity of matrix-like (array-shaped) individual modules 12, the external dimensions of the panel 15 being approximately 1 m to 1 m.

The individual modules 12 in turn contain a multiplicity of optically acting mesa diffraction bodies, which are likewise arranged in a matrix in regular rows and columns on a common support surface, which is not shown in FIG. 1 for reasons of increased clarity.

As can also be seen from FIG. 1, the individual modules 12 are of identical shape and are connected to one another, with further details being shown in FIG.

A control network consisting essentially of planar lines in the interior of each individual module 12 and contacts between the individual modules is provided in order to move the above-mentioned individual bodies with their mesa diffraction bodies in a targeted manner according to the invention by means of a corresponding electrical actuation on the basis of electrostatic forces. to achieve targeted color effects can. For this purpose, a supply line 20 is provided, which supplies a DC voltage of, for example, the order of 60V via a connection 21 provided for this purpose to a specially designed individual module 12.

Furthermore, a sensor 16 is provided, which is also operatively connected to the actuation network and is set up to receive control signals from a control unit 18 wirelessly or, if wired, then advantageously in an encapsulation with a connection for supplying power to the panel, in order to to individually electrostatically actuate individual individual modules 12 or individual mesa diffraction bodies or groups of mesa diffraction bodies. The sensor can be, for example, an infrared (IR) or an ultrasound - or a radio sensor. The control unit 18 contains the necessary hardware to run a program that contains all the algorithms that are necessary to move the mirrors according to a programmed movement. These algorithms have long been known from the prior art.

The corresponding driver programs for implementing a special control geometry and an associated special control network are also simple to manufacture for the person skilled in the art and are contained in the control unit 18.

With further reference to FIG. 2, the coupling between individual modules 12 from FIG. 1 is described in more detail.

Two individual modules 12 A and 12 B with a square contour lie flush with the edges and corners, with their respective edges lying against each other. Advantageously, a snap-in connection 22a and further snap-in connections 22b are each provided off-center in order to mechanically connect the two individual modules 12 A and 12 B to one another at two points. There is also an electrical contact 24 provided that establishes the electrical connection between the control network of the two individual modules. In

2 only two individual lines are shown, (+ and -) it is of course also possible to implement several such electrical contacts if this is appropriate for reasons relating to circuitry or manufacturing technology, for example because fewer crossing points intersect between them

Lines should result. In order to limit the complexity of the control network and the resulting complex boundary conditions of the manufacturing process for the implementation of these lines as a planar circuit during a thin-film manufacturing process, it is proposed to control entire groups of individual bodies together, so that the manufacturing is identical the individual body has a swiveling movement or lateral movement of the mesa diffraction bodies which is approximately the same for all. For example, one or more rows of individual bodies of an individual module 12 are suitable as subgroups. Likewise, one or more columns can be controlled together with the same control signal.

The circuit within a line can consist, for example, of a series connection of a complete line or specifically selected subsections of a line, depending on how large the voltage drop is during the activation of a single individual body. In order to be able to remain in the preferred low-voltage range, it can therefore be advisable to implement a parallel connection of series connections for the above-mentioned subgroups in a single line.

With further reference to FIGS. 3 and 4, the structural structure of an individual body that carries a mesa diffraction body is described below. The entire individual body is identified by reference number 31. On a base support surface 30, which was already mentioned above, is a Holding element 32 suitable cross section and with a suitable

Height provided in relation to the pivoting movement of the mesa diffraction body 36. A bridge element 34, which has an elongated shape and carries the mesa diffraction body 36, is fastened to the end section of the holding element 32 opposite the base support surface. The bridge element 34 has an end section with which it is attached to the holding element 32 and a free, air-floating end section so that it is flexible with its free end by a force which is directed upwards and downwards in FIG Rest position, which is shown horizontally in Fig. 3, can be deflected. In this case, the bridge element 34 advantageously represents the one electrode with at least one partial area, and the counterelectrode 38 is assigned to the base support surface 30 and firmly connected to it by a corresponding thin-film process.

As FIG. 4 shows, the bridge element is elongated and, see also FIG. 3, has a relatively thin thickness, so that a respective bending elasticity of the bridge element 34 suitable for the actuation stresses can be realized. The mesa diffraction body 36 is a separate layer and has a shape with which it can preferably be moved up and down in the manner shown in FIG. 3 without colliding with the bridge element itself or with the counterelectrode. Therefore, it preferably has a recess around a section of the bridge element 34 which is associated with the holding element.

The cross-sectional shape of the holding element 32 can be varied within a wide range, as long as the required strength is given in order to achieve a precise measurement

To be able to perform diffraction body movement. The edge dimensions a _x and a _{y of} the mesa diffraction body 36 can be varied within a wide range, the height and strength of the holding element 32 then having to be set up appropriately, so that there is a trouble-free movement of the mesa diffraction body 36. The edge lengths of the mesa diffraction bodies and their spacings can vary, at least in one direction, preferably in a range that is determined by the diffraction condition, edge length in the order of the wavelength, for example between 200 and 1400 nanometers. The exact shape and arrangement of the mesa diffraction bodies 36 should also be made dependent on the later intended use of the individual modules 12 or the panels 15. This is essential especially for holograms.

The contact between the bridge element 34, which is designed as an electrode, and the associated part of the connection network can preferably be made via the holding element 32 if the connection network, as is preferably arranged here in the lower region of FIG. 3, for example, just above the base support surface, in an expedient manner is electrically isolated from it. If the bridge element 34 consists of a metal or at least has a metal coating which at the same time has good electrical conductivity and good reflective properties, then the contact between the bridge elements and the connection network can be made, for example, via a through hole through the holding element 32, or alternatively it can also be on the edge seen from top to bottom in FIG. 3. The counterelectrode 38 likewise consists of conductive material and, depending on the design of the material of the base support surface 30, may also be separated from it by an insulating layer, which is not shown in FIG. 3 for the purpose of increased clarity. If the networks for the electrode and counterelectrode are supplied with voltage accordingly, so that an abutting or a repelling force arises between the electrodes, the mesa diffraction bodies, as indicated in FIG. 3, move according to the laws of electrostatics and the forces in an electrical field. With further reference to FIGS. 5 and 6, a further preferred exemplary embodiment for the configuration of an individual body or mesa diffraction body according to the invention is described in more detail below. In this exemplary embodiment, the mesa diffraction body 36 is fastened to two bridge elements 34 A and 34 B, the bridge elements in turn being fastened on their own holding elements 32 A and 32 B, respectively. As FIG. 6 shows in more detail, it is an asymmetrical arrangement, as shown as a variant in FIG. 7 b).

In this exemplary embodiment there is a pivoting movement of the mesa diffraction body 36 about an axis lying in the plane of the drawing in FIG. 5, since the bridge elements 34 A and 34 B are manufactured as easily twistable mechanical elements which, like in the previous exemplary embodiment, are activated via electrodes , In this case, the mesa diffraction body 36 is expediently used as an electrode, and two counterelectrons 38 A and 38 B are provided, which are arranged on opposite sides of the pivot axis, see FIG. 6 on the base support surface. In this exemplary embodiment, too, the mesa diffraction body 36 can be contacted via through holes through the holding blocks 32 A and 32 B. Only one pair of electrodes can also be provided.

In addition to the embodiment variants shown above, it should be noted that one and the same holding block 32 or 32 A or 32 B can not only serve for one bridge element 34, or 34 A or 34 B, but also for the next one

Bridge element can be used with. For this purpose, a bridge element expediently extends on one side and a bridge element on the opposite side of the holding element. With further reference to FIG. 7, embodiment variants for the above-mentioned exemplary embodiments are described below.

7 shows a schematic top view showing further details for the relative arrangement and orientation between the mesa diffraction body and the bridge element according to variants A), B) and C) according to the exemplary embodiment from FIGS. 5 and 6;

7a), the mesa diffraction body 36 is connected at the edge to the bridge elements 34 A and 34 B. In this embodiment, only a single pair of electrodes on one side of the pivot axis can be used to perform the mirror movement. This pair of electrodes would then advantageously be arranged at a specifically preselected distance from the swivel axis, both for the electrode on the mesa diffraction body and for the electrode on the base support 30.

In the variants shown in FIGS. 7B and 7C, pairs of electrodes can in principle be attached on both sides of the swivel axis, which is given by the bridge elements 34A and B. The variant shown in FIG. 7B contains the broadest possible variations in order to enable the mesa diffraction body 36 to be pivoted as extensively as possible. Because if the actuation voltage can be chosen large enough to be able to act on the short end 70, then a large angular range can be realized without the risk that the mesa diffraction body in its extreme deflection and touch the counter electrode for the case of attraction between the two elements.

For the sake of completeness, FIG. 7C shows once again the case of the symmetrical division of the mesa diffraction body halves. With further reference to FIG. 8, a further, preferred exemplary embodiment of the present invention is described, which is characterized in that an individual element is mounted in the manner of a gimbal bearing with respect to two pivot axes which are essentially independent of one another.

Fig. 8 shows a schematic plan view of an individual body of a preferred, further embodiment of the present invention, in which a mesa diffraction body is gimbaled. The holding elements 32 A and 32 B are assigned to the left or right edge of the illustration in FIG. 8. The bridge elements 34 A and 34 B lead from these holding elements, cf. 5 and FIG. 6 form a common swivel axis inwards and meet a swivel frame 80 there. This is designed as an electrode and can interact with one or two counter electrodes 38 A or 38 B, cf. the description of FIGS. 5 and 6. This results in a pivoting movement of the pivot frame 80 about the common pivot axis of 34 A and 34 B. A further pivot bearing is now provided within the pivot frame 80, namely about a pivot axis which is formed by an inner bridge element 84 A and another inner bridge element 84 B, each of which connect the swivel frame 80 to the mesa diffraction body 36 or its fixed support 86.

With further reference to FIGS. 9A and 9B, a variant of the particularly preferred embodiment according to FIG. 8 is shown and described in more detail, in which the two pivot axes are not at right angles to one another. Furthermore, the mesa diffraction body shape is also not rectangular, but has a cornerless outer contour, which is arbitrarily shown in FIG. 9 as an example, here approximately pear-shaped, to show that almost any shape treasures can be chosen here. This is also suitable for manufacturing of holograms. The actual structural design of the mesa diffraction body mounting changes only to the extent that it is necessary to constructively map the changed geometry of this irregular opening. For example, the locations of the electrodes are adapted accordingly, the spacing of the holding elements from one another, etc. In this respect, the description of the structure of the individual body with the rectangular gimbal-mounted mesa diffraction body (mesa) can be used for the further details. The technological tools of surface micromechanics described below are again used for the geometric design of the mesa spaces between the mesa diffraction bodies and the mesa diffraction bodies themselves. This distinguishes these actuatable (movable) holograms on the one hand by the manufacturing process and on the other hand by the changeability of conventional holograms (K. Buse, E. Soergel, Holography in Science and Technology, Physik Journal, 2, No. 3, page 37 (2003 The example of the gimbal bearing with the inner support 86 shown in FIG. 8 and the possibility mentioned there of lifting the individual element out of the plane of the swivel frame 80 results in the possibility of determining the size of the mesa-mesa diffraction body in the If the distance between the underside of the single element and the top of the swivel frame 80 is chosen large enough, the maximum possible swivel angle results from simple geometric considerations alone, until the mesa is reached, regardless of the size of its substructure, which is responsible for its swivel mounting - Diffraction bodies on an area of the swivel frame or the external holding elements te 32 strikes.

With reference to FIGS. 10, 11, 12 and 13, the effects are illustrated and described in the following, which are caused by systematic displacement of mesa diffraction bodies or groups of mesa diffraction bodies, or by pivoting the surface trained mesa diffraction body according to Figures 3 to 6 described:

10 shows a schematic plan view (detail) of a plurality of rectangular mesa diffraction bodies in a 2-row grating arrangement

The grid spacing is preset only in the x direction, and the unactuated starting position is shown at the top, and one of several feasible actuated positions is shown below, the previously constant grid spacing splitting into an enlarged and a reduced one;

11 shows a schematic plan view (detail) of a plurality of rectangular mesa diffraction bodies in a 3-row grating arrangement, the grating spacing being preset only in the x direction, the unactuated starting position being shown above, one of a plurality of realizable ones in the middle Actuated positions of a central section is shown, with nine mesa diffraction bodies are deflected from their rest position about their left-justified longitudinal axes, and the distances projected into the xy plane between the elements in this area are increased in the x direction (variation of the effective grating spacing) , The mesa diffraction bodies are shown below in a schematic side view along the paper plane of the middle representation;

12 shows a schematic plan view (detail) of a plurality of rectangular mesa diffraction bodies in a 3-row grating arrangement (grating spacing is preset only in the x direction, the unactuated starting position being shown above, in the middle one of several realizable actuating positions a central portion is shown, with nine mesa diffraction bodies are laterally displaced. The elements are moved in the lateral direction (in the xy-

Plane) shifted, with a slight offset movement being carried out in the z direction by a distance which is somewhat greater than the layer thickness of the elements in the z direction. From the perspective of the supervision (Fig. 12 middle) 3 elements in the right column have almost completely disappeared below the originally left neighbors by a movement in the x direction. Furthermore, in the middle column, 3 elements have partially disappeared below the originally left neighbors by moving in the x direction. In the left column, 3 elements have partially disappeared below the originally left neighbors by moving in the x and y direction. This is shown in a schematic side view along the paper plane of the middle representation in FIG. 12 below.

13 shows a schematic plan view (detail) of a grating arrangement with several rectangular and line-shaped diffraction bodies of different sizes, the optically effective surfaces which are formed by the interaction of at least one diffraction element being able to be enlarged or reduced by the actuation of these elements. If the optically effective, coherent fold of an ensemble of such mesa diffraction elements is reduced, the adjacent slit areas increase. If the optically effective, coherent fold of an ensemble of such mesa diffraction elements increases, then the adjacent slit surfaces decrease.

The following are basic guidelines for the manufacture of a diffraction body device according to the invention. First of all, it has to be ascertained that the basis of the production is the usual thin-film production processes known in the prior art, in which thin layers are produced by vapor deposition, spin-coating, dip coating, sputtering, galvanizing, etc., and by others lithographic manufacturing processes can then be structured on a small scale and mostly in a surface micromechanical structure to the previously applied layers, depending on how large the structures in the photomask are. In this regard, reference is made entirely to textbooks that describe the aforementioned techniques.

Manufacturing process based on surface micromechanics:

The most important production features for the exemplary embodiment shown in FIG. 5 are explained below as follows:

I. For use as a facade element and for producing single modules of square shape with an edge length of just under 12.5 cm, a thin glass pane is used as the base substrate 30 as a glass substrate with these dimensions. Instead of inorganic glass, another transparent material, organic glasses (e.g. plexiglass), transparent plastics or polymers, possibly with the addition of a tinting color, can be used.

II. In a second step, planar electrodes 38 A and 38 B and the associated control network for the conductor tracks are, for example, by vapor deposition of conductive materials, e.g. Metals (aluminum, ...) or e.g. ITO (indium tin oxide), or e.g. Conductive polymers (poly [p-phenylene], ...), optionally supported by a galvanic reinforcement, are applied to the glass substrate 30. This

The step can be carried out by vapor deposition of the electrically conductive materials, combined with conventional lithographic structuring techniques. In the case of line crossings, lines are separated from one another as usual by an insulating intermediate layer. purple). In a third step, one is applied

Sacrificial layer with a defined thickness, which is essentially predetermined by the height of the holding elements 32 A and 32 B shown in FIG. 5. The height of the sacrificial layer should be at least so high that the intended maximum swivel deflection of a mesa diffraction body 36 can take place without the mesa diffraction body bumping against the base plate 30. This sacrificial layer is intended to form the holding blocks 32 A and 32 B. At these points, it must subsequently be preserved, and at all other points, the sacrificial layer is subsequently etched away in order to form a free space which enables the later pivoting of the brass diffraction body. In order to ensure a high level 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 e.g. electrical cables made of transparent ITO, holding blocks made of plexiglass and base plate made of inorganic glasses can be produced.

The materials of the sacrificial layer are primarily those materials which can be selectively etched compared to all other materials used and which are relatively insensitive to weather, moisture and temperature differences, have sufficient mechanical strength and have no appreciable plastic flow (without Hysteresis). For example, materials such as polymethyl methacrylate, silicon dioxide or a UV photoresist are suitable as long as it can be applied with a defined thickness.

The material class of thermotropic main chain liquid crystalline polymers may also be mentioned by way of example. On the one hand, this class of material can be easily solved with certain organic solvents (sacrificial layer property) and on the other hand also fulfills relatively high, mechanical ones Stability criteria if these materials are used simultaneously as part of the holding blocks.

III. b). As an alternative to purple), a variant is specified which provides holding blocks with increased strength. Process step purple) is essentially replaced as follows. For this purpose, a deep-lithography-capable photoresist (e.g. PMMA) is applied, in which the shapes of all holding blocks are defined as negative by exposure and development. Stable holding blocks are defined by selective filling, for example by means of galvanic processes. Process steps IV, V, and VI which follow below are applied, the remaining photoresist (sacrificial layer) being removed by wet chemical means. Furthermore, process step II is to be modified in such a way that, at the same time as the electrodes on the base plate, suitable conductive base layers of the holding blocks are defined, each of which has the shape of the connecting surface of the holding block / base plate. Care must be taken to ensure electrical insulation between the upper and lower electrodes. The use of LIGA technology with cost-effective molding steps can also be used with advantage.

IV. In a further production step, a layer is applied which forms the mesa diffraction bodies or, according to a special embodiment variant, the optical filters, and the bridge elements 34 A and B with their holding layers on the holding elements 32 A and B. A metal layer made of aluminum, for example, or a dielectric multilayer with an outer, electrically conductive but transparent layer (e.g. ITO) or a polymer layer with highly reflective and conductive properties can be considered as the material.

In a cost-effective exemplary embodiment, the conductive layer extends over the mesa diffraction bodies, which bridges and over the holding layers, and also serves as an electrode (especially on the mesa

Diffraction surfaces), as a conductor track (especially on the

Connecting bridges) and as holding layers on the holding elements.

V. In a further step, circumferential spacers are preferably applied to the edge of each individual module, for example made of the same material as the aforementioned sacrificial layer, in order to be able to effect the application of an outer protective layer in a further (later) step, which is flat over the entire Module surface extends to realize a hermetic sealing against dust and moisture as well as a voltage protection. This protective layer can be applied, for example, to the aforementioned spacers, which is particularly preferably in the form of a peripheral edge, by gluing.

VI. In a next step, the vertical structuring is carried out by performing an etching process perpendicular to the base plate 30. The parts of the sacrificial layer described above are then selectively removed, producing the connecting bridges and mesa diffraction bodies.

VII. In a further step, the connection plugs for the electrical connection of the individual modules to one another, see back to FIG. 2, for the electrical contacts 24 and the mechanical connections 22 are applied and fixed to the module frame or conductively for the electrical contact with the control network connected.

Likewise, the communication sensor 16 mentioned above in the description of FIG. 1 is contacted with the location on the control network provided for this purpose, and the above-mentioned connection contact for the DC voltage supply line 20 is made with a suitably provided connector plug 21 preferably provided on only one module, for example the individual module 12, which is later assigned to one of the corners of the window area.

Optionally, depending on the later use of the module manufactured in this way, a hermetic sealing lacquer can be applied over the entire edge area of the module, so that the interior of the module maintains a long-term stable, weather-resistant state.

The modules thus produced are then plugged together, as is sketched in FIG. 2, until a panel of the desired size is formed. For example, with a single module size of 12.5 cm x 12.5 cm, a grid of 8 x 8 individual modules can be put together in order to obtain a coherent panel with a surface area of 1 square meter. For this purpose, the individual modules 12 advantageously also have suitably pluggable snap-in connections 22 A and B on the other edges, which are not shown in FIG. 2. The snap-in connections in the transverse direction can also be of another type - for example an L-shaped catch - compared to the type of the longitudinal direction as shown in FIG. 2, in order to simplify the plugging together.

In an optional manner, this entire panel can now be applied to a further carrier 15, for which a further glass pane can be used, for example. This would be particularly recommended if increased mechanical stability of the entire panel was required.

Alternatively, the connecting bridges, mesa diffraction bodies and holding blocks can be set up from originally flat elements (see, for example, MH Kiang, et al. IEEE Phot. Technology. Lett. 8, 1707 (1996). The mesa diffraction body arrangement according to the invention can, as will be clear to the person skilled in the field of thin-film production and microstructuring, be produced in many different ways. Characteristic of the manufacturing method according to the invention is therefore only the use of those materials which allow a reasonable price / performance ratio for large-area use in the window or facade area, and the adaptation of the lithographic process to the relatively small dimensions of the mesa diffraction bodies.

Furthermore, it is advantageous to preferably design the overall system according to the invention in such a way that it can be operated in a low-voltage range of less than approximately 60 volts. This specification is to be taken into account in the shaping of the individual bodies, that is to say for holding element 32, bridge element 34 and individual element 36, with regard to the leverage forces to be constructed, so that the actuation voltage amounts required during implementation by electrostatic attractive forces do not become too high.

A slight variation of the mesa diffraction body curvatures due to outside temperature still causes periodic color shifts over longer periods of time.

In the case of amplitude gratings, the color is determined by the dimensions of all elements and the pulse duty factor between gap surfaces and absorbing or scattering surface components. Color variations of the diffraction pattern then result from variation of the pulse duty factor through variation of the angle of attack of diffraction surfaces of the mesa diffraction bodies, or through lateral displacement of the diffraction bodies in certain groups, relative to other groups. The following angular ranges are mentioned as typical for certain uses, as follows: For advertising spaces where only an axis of rotation is required, an effect can already be achieved with a change in the swivel angle of approximately 2 degrees, with "art in construction", ie aesthetic color design for building facades, visible results can be achieved with an angle of only one degree, with more intensive effects only occur at larger angles. With lateral displacement, the effect depends on the particular arrangement with which the pulse duty factor is changed.

The relevant expert in the respective field of the different uses outlined above for the mesa diffraction body arrays according to the invention will recognize that an overall system according to the invention can advantageously be operated with further sensors, which are then specifically selected for the respective use. For example, for all uses in connection with solar radiation, a sun position sensor and optionally an additional further sensor system can advantageously be used, which detects the cloud distribution and / or the brightness distribution in the sensor-detected half-space, or directly in the sky.

Although the present invention has been described above on the basis of preferred exemplary embodiments, it is not restricted to these but can be modified in many ways.

Thus, depending on the design and the type of material of the base support surface 30, the device according to the invention can be designed to be more flexible than “diffraction foil”, or more solid, possibly stronger and thus plate-like.

For example, the dimensioning of the area of the individual modules can be adapted to manufacturing systems that already exist and were previously used to manufacture integrated circuits (IC) components, hard disks in the computer area, etc. Furthermore, the electrode assigned to the individual body can also be formed integrally with the latter if the latter consists of electrically conductive material.

For example, the surfaces of the individual bodies 31 facing the light source can also be mirrored. Then, in addition to the diffraction of the light, at least part of the incoming light is reflected again, which has a special, rarely seen optical effect.

Finally, the features of the subclaims can be combined essentially freely with one another and not through the sequence in the claims provided they are independent of one another.

It should be noted that gratings can be divided into two classes: reflection gratings and transmission gratings. In both cases, further subdivisions are made depending on whether phase differences or amplitude differences are involved. Accordingly, there are phase transmission gratings, phase reflection gratings, amplitude transmission gratings and amplitude reflection gratings. This is shown in Fig. 14. As an example and in order to increase the clarity of the presentation of the actual invention, the amplitude reflection grating was used in most cases in the text. However, it will not be difficult for the person skilled in the art to transfer the actual facts according to the invention to the other grating types mentioned.

In this context, the word "reflection" here does not necessarily mean reflective elements. It indicates that the diffraction pattern is observed on the same side of the grating on which the light is incident (see FIG. 14). The elements only have to In the case of transmission gratings, the diffraction pattern is based on observed on the other side of the grating from which the light is incident (Fig. 14).

Amplitude transmission gratings have opaque elements 97 and translucent elements 96. Amplitude reflection gratings have light-scattering (in special cases reflecting) elements 94 and light-transmitting (or light-absorbing) elements 95. In one exemplary embodiment, these can be mesa (ribs, webs) and mesa spaces (gaps, furrows). Phase transmission gratings have at least two different translucent elements, which differ in that a phase shift of the light occurs between adjacent elements. In one exemplary embodiment, these can be glass mesa 92 and fluid-filled mesa spaces 93. Phase reflection gratings have at least two different light-scattering or light-reflecting elements, which differ in that a phase shift of the light occurs between adjacent elements. In one exemplary embodiment, the mesa 99 and the bottoms of the mesa spaces 98 can consist of surface-mirrored glass. The phase difference results solely from the height difference between the mesa spaces and the mesa, the wavelength, the angles of incidence and reflection and the refractive index of the fluid medium in the mesa spaces. In Fig. 14, the actuability of the mesa elements and the mesa gaps is not shown for reasons of greater clarity and only a massive lattice structure is shown.

Further applications can be realized for building rooms if a controllable transmission grille is used in the window surfaces: for example, customized room color variations on the room walls and ceilings, projection displays for projections on walls and ceilings, projections of art objects on room surfaces or inventory, For example, projections of famous paintings on wall surfaces, and the like.

If the base support surface is not to be flat, but rather has an arbitrarily curved shape, for example in order to adapt it to the individual shape of car body parts, it may be expedient to produce the diffraction device 12 according to the invention on a thickness-adapted film as base support 30 in order to to ensure the necessary flexibility. Individually curved modules can then be integrated at a suitable point in the manufacturing process during bodywork processing, especially during painting.

Claims

Diffraction foil with a 2-dimensional grating arrangement

1. diffraction device (12) for the two-dimensional diffraction of light beams with a plurality of individual bodies (31) _r connected to a common base support surface (30) _r , the individual bodies being arranged and spaced from one another such that they act as diffraction centers for the light beams, and wherein the individual bodies are structural elements from a thin-film production process, characterized in that an individual element (36) as part of an individual body (31) is mounted to be movable relative to the base support surface (30) for an actuation mechanism acting jointly on an individual element or on groups of individual elements in order to vary the effective grid spacing between adjacent individual bodies or individual elements.

2. Device according to the preceding claim, wherein the actuation mechanism contains a predetermined number of comb actuators.

3. Device according to claim 1 or 2, wherein the actuation mechanism is based on electrostatic forces.

4. The device according to claim 1 to 3, wherein an actuation mechanism for the lateral displacement of individual bodies (31) or individual elements (36), or groups thereof (31, 36) is provided to the effective grid spacing between adjacent individual bodies or individual elements in a first direction to vary.

5. The device according to the preceding claim, wherein an actuation mechanism for the lateral displacement of single-body pern (31) or individual elements (36), or groups thereof (31,

36) is provided in order to additionally vary the effective grid spacing between adjacent individual bodies or individual elements in a second direction.

6. The device according to the preceding claim, wherein the second direction is oriented perpendicular to the first direction.

7. The device according to claim 2, wherein the individual elements (36) are flat and are mounted on fixed to the base support surface (30) or a Kaπvmaaktuator holding elements (32), the storage movement of the individual elements (36) by an electrostatic actuation mecha - nism allowed.

8. Device according to one of the preceding claims, wherein a) the material for the base support surface (30) is selected from the group: organic or inorganic glasses, plastics, in particular polymers, metals, bl) the material for the individual body (31) is selected such that it is suitable as a sacrificial layer in an etching process, selectively for one of the selected materials, or b2) the material for the individual bodies (31) is selected such that it allows selective growth, in particular by applying electroplating in depth-lithographically shaped polymethyl methacrylate (PMMA).

9. The device (12) according to claim 1, wherein it contains connecting elements (22, 24) with which it can be edge-connected to other devices (12) of the same type.

10. The device according to the preceding claim, wherein it contains plug-in connecting elements (22, 24), wherein the In addition to the mechanical connection, connecting elements also contain an electrical plug connection between devices of the same type.

11. Device according to one of the preceding claims, wherein the individual body (31) or the individual elements (36) are arranged in a regular matrix form from parallel rows and parallel columns.

12. Panel (15) containing a device (12) or

A plurality of devices (12) according to any one of the preceding claims.

13. Panel (15) according to one of the two preceding claims, further comprising a power supply connection (21) and a device (16) for receiving control commands from a control device (18).

14. System for the design of building facades, comprising one or more panels (15) according to the preceding claim

Control device (18) for controlling the effective grid spacing between adjacent individual bodies (31) or Ednzele ends (36) of the panel (15), and a device for transmitting control signals to the panel (15).

15. A lithographic method for producing a device (12) according to claim 1 to 11, characterized in that a) the material for the base support surface (30) is selected from the group: organic or inorganic glasses, plastics, in particular polymers, metals, bl) the material for the individual bodies (31) is selected such that it is suitable as a sacrificial layer in an etching process selectively for one of the selected materials, or b2) the material for the individual bodies (31) is selected such that it allows selective growth, in particular by arrival apply electroplating in deep lithographically shaped polymethyl methacrylate (PMMA).

16. Use of a device (12) according to one of the preceding claims 1 to 11, or a panel (15) according to claim 12 or 13, or a system according to claim 14 for the design of building facades including their windows or walls.

17. Use of a device (12) according to any one of the preceding claims 1 to 11, or a panel (15) according to claim 12 or 13, or a system according to claim 14 for the design of surfaces, in particular body parts of mobile systems, including their windows ,

18. Use of a device (12) according to one of the preceding claims 1 to 11, or a panel (15) according to claim 12 or 13, or a system according to claim 14 as a decorative object for achieving color effects.