LU102920B1 - Device and method for laser interference structuring of substrates with periodic dot structures for anti-reflection properties - Google Patents

Abstract

The present invention relates to the field of structuring substrates with periodic point structures in the micro- or sub-micrometer range, in particular to a device and a method for structuring surfaces and the interior of a transparent substrate using laser interference structuring. The structuring created in this way with periodic point structures in the micro- or sub-micrometer range is characterized by a pronounced anti-reflection property. In addition, the present invention relates to a structured substrate with anti-reflection properties, which comprises a periodic dot structure.

Description

Device and method for laser interference structuring of substrates with periodic LU102920

Dot structures for anti-reflection properties

Technical area

The present invention relates to the field of structuring substrates, in particular to a device and a method for structuring surfaces and the interior of a transparent substrate using laser interference structuring. In addition, the present invention relates to a structured substrate - flat ones are examples here

Substrates, especially so-called anti-reflection glazing - with

Anti-reflection properties comprising a periodic dot structure.

State of the art

Methods for treating surfaces are known from the prior art, with which the surface of transparent substrates, in particular glass, but also solid ones

Polymers can be changed so that the reflection of the substrate can be reduced. Typical processes apply an additional material to the surface of the substrate to be anti-reflective (so-called structure or layer-building processes), whereby the refractive index of the different materials differs.

In US8557877B2, for example, a possible layer-building method is explained. A coating solution is made from at least two chemical substances

Starting materials are generated, their pH is then reduced and then optionally diluted with another solution before the coating is applied to the desired substrate. This type of coating process uses various chemical substances that often have low environmental compatibility

Disposal and handling is costly and time-consuming.

This type of process involves a reduction in the degree of reflectance through destructive

interference. The refractive index of the material used for the

Coating is used must be tailored to the substrate to be coated and the medium that is in front of the substrate (usually air). Not every one

Coating material can be processed in the same way, after such a method it is necessary to use different processes for coating different substrate materials.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

US10459125B2 therefore describes a method in which a LU102920 so-called moth-eye structure is chemically generated on a substrate by applying a polymer film to the substrate. This type of structure is based on the principle of the moth's eye, on whose surface there are regularly arranged nanostructures whose dimensions are smaller than the wavelength of the light hitting them. This creates a layer with a graded refractive index at the transition from the medium in front of it

Substrate is located, and the substrate itself generated, which significantly reduces the reflection.

A film produced in this way can be used regardless of the substrate to be coated, since the reduction in reflection does not depend on the refractive index of the material used for the

Coating used depends. However, the coating method is still based on chemical substances with the disadvantages already mentioned above.

In addition, a coating created in this way is susceptible to mechanical stress (abrasion, impacts, etc.) and therefore ages quickly. After a while it comes off

Coating therefore often separates from the substrate and/or loses its anti-reflection properties

Characteristics.

WO 2019/166836 A1 explains a method for producing an anti-reflection structure in which the surface of a substrate is processed using a laser in such a way that it receives anti-reflection properties. Here, the substrate material is modified with a focused laser beam, thereby creating a nanostructure through self-organization processes using laser-induced periodic

Surface structures (Laser-induced Periodic Surface Structures — LIPSS) are generated.

By appropriately selecting the laser fluence and superimposing the beam focal points on the substrate surface, a quasi-periodically repeating structuring can be generated. This results in an anti-reflection surface. There won't be any

Chemicals are required and a wide range of substrate materials can be used

processed in this way.

However, this process works gradually and is dependent on the underlying

LIPSS self-organization process is time-consuming. A flat nanostructure creation in one step is not possible because the LIPSS only develop through repeated processing of nearby surface areas. In addition, the regularity of the structure depends on the specific process or environmental conditions, so that deviations in the

Surface condition (material slightly different, microscopic contamination) can lead to changed results.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

EP2431120A1 discloses a method for directly structuring a thin film LU102920, in which periodic structures are formed in thin films using interfering laser beams

Metal films can be produced. Here, several pulsed laser beams are directed onto the thin film, whereby they interfere in an interference area, so that the material of the thin film is evaporated in the areas of high intensity. The

The process is characterized in that the resulting structure is formed by the

Setting the intensity of the laser beams or the displacement of the film in the z-direction (i.e. in the direction of the incident laser beams or away from them) can be changed. A phase difference between the two is created using additional optical elements

Laser beams are generated that influence the interference pattern. The invading ones

Laser beams are focused onto the surface of the thin film by a focusing element and are reduced in size, resulting in areas of high intensity in which the material of the thin film is evaporated.

This process requires a way to modify the intensity of the incident laser beams. This can be done either by specifying a specific one

Laser radiation source or a unit for controlling the intensity of the laser beam. The intensity must be adjusted depending on the evaporation threshold of the thin film material. This means that different laser radiation sources must be used for different materials, or an additional one

Element for intensity control is needed. Shifting the optical elements does not allow the resulting interference pattern to be controlled. When processing

Materials with a high evaporation threshold can also damage the optical elements in the laser beam path.

Task

It is therefore the object of the present invention to provide a device and a method with which a direct structuring of surfaces, for example transparent and/or flat surfaces, which gives the material anti-reflective properties, can be produced without the use of environmentally harmful chemicals.

It is also an object of the present invention to be as robust as possible

To create structuring that does not lose its effectiveness through use of the transparent substrate. In addition, the structuring of flat samples should be possible within a short time.

A further object of the invention is to provide a method for structuring using

To provide laser interference, which is independent of the intensity of the

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Laser radiation source is. The procedure should be set up in such a way that even at high = LU102920

Intensities on the substrate to be structured do not damage the optical

elements occur.

Solution

The present invention provides a device which:

Structuring of substrates, for example flat and/or transparent substrates using

Laser interference structuring enables. Using this device you can

Surface or inside transparent substrates with periodic dot structures

Dimensions in the micro- and sub-micrometer range are created, which correspond to the substrate

Give anti-reflection properties (increased transmission).

The present tasks are achieved according to the invention by means of a

Laser interference structuring device for direct laser interference structuring of a

Substrate - examples include flat and/or transparent substrates - solved according to claim 1, comprising - a laser radiation source (1) for emitting a laser beam, - a beam splitter element (2) which is arranged in the beam path (3) of the laser beam, - a focusing element (4), which is set up in such a way that the partial beams pass through it in such a way that the partial beams are on the surface or in the volume of a

Substrate, preferably flat and/or transparent substrate (5) in one

Interference region can be interfered with, wherein the beam splitter (2) is freely movable along its optical axis in the beam path (3), and wherein the beam splitter (2) is designed to reflect the incident laser beam, which is emitted by the laser radiation source (1), in at least 3, preferably at least 4

Partial beams, in particular 4 to 8, i.e. 4, 5, 6, 7, or 8 partial beams.

The beam splitter (2) is particularly preferably set up in such a way that it absorbs the incident beam

Laser beam is divided into an even multiple, i.e. 4, 6 or 8 partial beams, most preferably 4 partial beams.

Alternatively or in addition to this, a beam splitter (2) can be provided such that it comprises a first beam splitter and at least one further beam splitter arranged downstream of the first beam splitter, the first beam splitter dividing the incident laser beam into at least 2 partial beams and the further beam splitter into at least one

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Beam path of a partial beam is arranged and this partial beam divides at least 2 partial beams as it passes through LU102920.

For laser interference structuring of the substrate (5), preferably flat and/or transparent substrate, the radiation emitted by the laser radiation source is used

Laser beam through the beam splitter element (2) in at least 3, preferably at least 4

Partial beams divided. Only two-beam interference (i.e. structuring by means of interference of two partial beams) is known from the prior art. Such

However, two-beam interference only creates line structures on the substrate.

The partial beams are then deflected by the focusing element (4) in such a way that they interfere in an interference region on the surface or inside of a substrate (5), preferably a flat and/or transparent substrate.

This makes it possible to create a two-dimensional, periodic point structure with dimensions in the micro and submicrometer range, the structure period of which can be freely adjusted by moving the beam splitter element (2) along its optical axis. A flat one

Processing a substrate (5), preferably a flat and/or transparent substrate, is possible.

Further advantageous embodiments can be found in the description and the subclaims.

General benefits

The advantage of the device defined here is that it:

Device and the process that can be implemented with its help in structuring

Substrates, especially when producing a structure with anti-reflection properties, the use of chemicals and their laborious disposal can be dispensed with. In addition, the cleaning of the substrates can be dispensed with.

Furthermore, a wide number of substrates, preferably flat and/or transparent substrates, in particular transparent materials, can be processed with the device. Since the process does not depend on the refractive index or the adhesion of certain coating materials to the substrate, this process is more flexible than conventional chemical processes.

In comparison to WO 2019/166836 A1, the processing time according to this method is significantly shorter, since the periodicity of the structures is due to the interference of the incident, at least 3, preferably at least 4 partial beams in an interference region

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application is guaranteed and does not come about through time-consuming self-organization processes LU102920. Another advantage over conventional methods is that the shape (structural design; geometry) of the micro/nanostructures produced can be controlled. The structures in the geometry can be controlled by the number of interfering (partial) beams, their polarization, and the setting of the process parameters, thereby specifically influencing the anti-reflection properties.

Furthermore, the stability of the periodic point structure created in this way should be mentioned, which is

Compared to conventional coatings, it is more durable because it cannot detach from the substrate to be coated over time and the use of the material.

If the structuring is carried out in the volume, i.e. in the interior of the substrate, preferably flat and/or transparent substrate, in particular in the transparent material, the resulting structuring (i.e. the periodic dot structure of the structured substrate) is less sensitive to impacts and abrasion than conventional ones

Coatings. The inventors have discovered that structuring (also referred to herein as texturing) inside the material (i.e. below the surface) does not necessarily produce anti-reflection properties. However, the texturing inside the material is interesting for other areas of application, such as product protection, optical

data storage, decoration, etc.

It is particularly advantageous that the structure of the device disclosed herein or the arrangement of the optical component enables substrates with very high structuring rates of up to 0.9 m#min, in particular in the range from 0.01 to 0.9 m2?2/ min, particularly preferably in the range from 0.05 to 0.9 m?/min, very particularly preferably in the range from 0.1 to 0.9 m?/min. This is ensured by the fact that the area in which the at least three partial beams are superimposed can be expanded by a preferred selection of optical elements, whereby a large area can be irradiated in one processing step. In contrast to methods known to those skilled in the art, such as direct laser writing, no strong focusing is necessary to produce high-resolution features.

Detailed description

The device according to the invention describes a structure for

Laser interference structuring of substrates, for example flat and/or transparent ones

Substrates for producing a structured substrate, comprising a periodic

Dot structure in the micro- or sub-micrometer range, especially for producing a

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application so-called anti-reflection glazing on the substrate or in the volume (i.e. within) this LU102920

substrates.

Substrate

In the context of the invention, the term substrate refers to a substrate whose surface extends in several spatial directions. A substrate, preferably a flat and/or transparent substrate, can be a planar substrate or a curved substrate, for example a parabolic substrate. Under flat is in

For the purposes of the invention, it is further to be understood that the extent of a substrate, preferably a flat and/or transparent substrate, for example a planar substrate in the x and y directions, or the extent of a curved substrate along its radius of curvature is greater than the extent of the area in which the at least three partial beams interfere with each other.

In a preferred embodiment, the substrate is a substrate whose extent in the x and y directions, or whose extent along a radius of curvature, is less than or equal to the extent of the region in which the at least three partial beams interfere with one another. A homogeneous structuring of the

Substrate is possible in one processing step (during a laser pulse).

In a particularly preferred embodiment, the substrate is a flat substrate, its extension in the x and y directions, or its

Expansion along a radius of curvature is greater than the extent of the area in which the at least three partial beams interfere with one another. By moving the substrate in the x and y planes, a flat, homogeneous structuring of the substrate is achieved in several ways

Processing steps (with several laser pulses) possible. The movement of the substrate can be possible through rotation or translation.

For the purposes of the invention, the term substrate includes a solid material with a reflective surface. Examples of such materials are metals, polymers,

Ceramics and glasses.

With regard to the substrates resulting from the application of the invention

Laser interference structuring process can be processed with a periodic dot structure with anti-reflective properties, within the scope of the present invention there is a wide selection of transparent and translucent but also non-transparent materials.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In a particularly preferred embodiment, the flat substrate comprises a LU102920 transparent material.

In general, the transparent material has a high permeability to what is visible

light, but this varies depending on the application. The transmittance of the transparent material is not less than 70%, preferably not less than 80%, more preferably not less than 90%, without deviation in the spectrum in the visible light range (wavelength 380 nm to 780 nm).

For the purposes of the present invention, a transparent material includes transparent

Materials, especially glass (e.g. borosilicate glass, quartz glass, alkali-alkaline earth

Silicate glasses (e.g. soda-lime glass), aluminosilicate glasses, metallic glasses), but also solid ones

Polymers (e.g. polycarbonates, such as Makrolon® and Apec®; polycarbonate blends, such as

Makroblend® and Bayblen®; polymethyl methacrylate, such as Plexiglas®; Polyester;

polyethylene terephthalate, polypropylene, polyethylene) as well as transparent ceramics (e.g.

Spinel ceramics, such as Mg-Al spinel, ALON, aluminum oxide, yttrium aluminum garnet,

Yttrium oxide or zirconium oxide) or mixtures thereof. are polycarbonates

Homopolycarbonates, copolycarbonates and thermoplastic polyester carbonates.

According to a particularly preferred embodiment, the transparent material consists of a glass (as defined herein) or a solid polymer (as defined herein).

Alternatively, the substrate, preferably a flat and/or transparent substrate, can also comprise a non-transparent material. By structuring the non-transparent

Material becomes periodic on the surface of the non-transparent material

Dot structure created in the micro or submicrometer range. As a result, a structure with anti-reflection properties can be created on a non-transparent material, with the original roughness of the surface of the non-transparent substrate (i.e. before the structuring according to the invention) remaining unchanged or almost unchanged in the macroscopic range, which effectively reduces reflection of an otherwise reflective surface non-transparent material, for example a metal surface, is induced. Metals (e.g. silicon,

aluminum, copper, gold), metallic alloys (e.g. steel, brass), ceramic

Materials (e.g. zirconium oxide, titanium dioxide, zirconium dioxide) and polymers (PEEK,

polyether ether ketones; polyfluorinated hydrocarbons, such as Teflon) and combinations thereof.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Point structure/interference pattern/anti-reflection glazing LU102920

The present invention also includes a structured substrate (5).

Anti-reflection properties, wherein the structured substrate has a periodic

Point structure in the micro- or sub-micrometer range, the periodic

Point structure is formed from inverse cones, and wherein the inverse cones are arranged periodically with a distance from one another based on their respective saddle point or height center (circular base area) in the range of 50 nm to 50 μm.

In the context of this invention, the term inverse peg refers to structures with a circular base that taper into the substrate in a vertical direction and have a rounded cone tip at their saddle point. The inverse cones are used during the structuring process, i.e. when a laser pulse hits

As a result of the impact of an area of high intensity in the substrate to be structured, the areas between the inverse pins on or within the

Substrate ideally through destructive interference whose intensity is zero

Remain essentially unstructured. Consequently, by focusing on the

Partial laser beams on or within the substrate are the negative of what the

Intensity distribution specifies, trained.

The period of the structure is referred to as À in the sense of the invention. It depends on the wavelength of the interfering laser beams, the angle of incidence of the interfering laser beams and the number of interfering laser beams.

A structured substrate with anti-reflection properties, here referred to as anti-reflection glazing, describes in the sense of the invention a substrate, preferably flat and/or transparent substrate, with a periodic dot structure with structure widths in the micro- and sub-micrometer range, i.e. in the range from 50 nm to 50 μm. These _anti-reflection properties come about when the dimensions of the generated

Structure, i.e. the structural period and dimensions of the individual cones, lie in areas smaller than the wavelength of visible light.

In physics, reflection is the throwing back of an electromagnetic object

Wave at an interface of materials with different refractive index. The

Reflection angle and the transmission angle of light in transparent substrates can generally be calculated using Snell's law of refraction as n, are, = n,Sin6, where ny and na indicate the refractive index of air and the substrate and 54 and 02, respectively, the angles of the incident and reflected beam.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Due to the periodic dot structure on the surface or in the volume of the substrate, preferably flat and/or transparent substrate, the refractive index of the substrate changes in such a way that a gradual refractive index results. That has to

The consequence is that light with wavelengths greater than the structural period A of the periodic

Point structure is increasingly transmitted. Light with wavelengths less than or equal to the periodic dot structure is diffracted at the surface.

For the purposes of the invention, anti-reflection properties refer to periodic point structures whose dimensions are in the range of the incident electromagnetic wave, so that the incident wave is diffracted away from the viewer in such a way that no reflection is perceived as “disturbing”. In addition, the term includes anti-reflection properties

The meaning of the invention also means that the refractive index is at the border between the first

Medium, for example air, and the substrate, preferably flat and/or transparent

Substrate, is gradual, so there is no clear for the incident electromagnetic wave

There is a transition from one medium to another and the incident electromagnetic wave is increasingly transmitted.

For the purposes of the invention, a structured substrate with anti-reflection properties also describes such a substrate which comprises a periodic dot structure, the periodic dot structure consisting of superimposed structures, with at least one

Structure has dimensions in the submicrometer range, and wherein at least one

Structure is formed from inverse cones, which in particular interfere

Laser beams can be generated.

For example, periodic point structure, especially the periodic

Point structure made of overlapping structures when using interfering ones

Laser beams through appropriate design of the parameters (selection of the

Laser radiation source, arrangement of the optical elements) can be optimally adapted to the requirements of the respective application.

In particular, a structure is a periodic point structure of inverse cones with average dimensions in the micrometer range, in particular with an average distance based on their respective saddle point or height center of 1 μm to 50 μm. Another structure is superimposed on this periodic point structure, with the average dimension of the superimposed structure preferably having dimensions in the range of

Laser wavelength A, or A/2, in particular from 100 nm to 1000 nm. In the sense of the

According to the invention, such a structure is also referred to as a hierarchical structure.

In particular, the superimposed structure has a quasi-periodic wave structure, with the material on the surface of the substrate in the area of the superimposed

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Structure has a sequence of wave crests and troughs, the periodicity of which is in LU102920

Submicrometer range, particularly preferably in the range from 100 nm to 1000 nm.

The wave structure is formed during the structuring process, i.e. when a

Laser pulse is formed in the substrate to be structured as a result of the appearance of a high intensity area, the structuring being carried out by one

Self-organization process takes place, which is stimulated by the at least partial melting of the substrate material by means of a laser pulse in a high intensity area. In particular, the wave structure is created using laser-induced periodic surface structures.

LIPSS), whereby the appearance of these surface structures is coupled to the generation of the periodic point structures using interfering laser beams.

A flat structuring of a substrate, for example with, is therefore advantageous

Anti-reflection properties through interfering laser beams and using laser-induced periodic surface structures possible without a long

Processing time or a large number of process steps that can be carried out successively must be accepted. The invention thus enables simultaneous generation of hierarchical

Structures that are used in the technical area both in the area of substrates

Anti-reflection properties, as well as in the area of self-cleaning, hydrophobic or superhydrophobic, as well as hydrophilic or superhydrophilic substrates with anti-icing and / or anti-fogging properties can be used.

Laser radiation source (1)

The device according to the invention consists of a laser radiation source (1), which has a

Laser beam emitted. The radiation profile of the emitted laser beam corresponds either to a Gaussian profile or a top hat profile, particularly preferably a top hat profile.

The top hat profile is helpful for structuring or covering a surface of a substrate that needs to be structured more homogeneously.

In a particularly preferred embodiment, the laser radiation source (1) is a source that generates a pulsed laser beam. The pulse width of the pulsed

The laser radiation source is, for example, in the range from 10 nanoseconds to 10

Femtoseconds, in particular 1 to 200 picoseconds, most preferably 1 to 20

Picoseconds.

Unless expressly stated otherwise, the term laser beam or partial beam does not mean an idealized beam of geometric optics, but rather a real beam of light, such as

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application, for example, a laser beam that is not infinitesimally small, but rather an extended one LU102920

Beam cross section (Gaussian distribution profile).

By top hat profile or top hat intensity distribution is meant an intensity distribution that can be essentially described, at least with regard to one direction, by a rectangular function (rect (x)). Real intensity distributions that have deviations from a rectangular function in the percentage range or inclined edges are also referred to as top hat distribution or top hat profile. Procedure and

Devices for generating a top hat profile are well known to those skilled in the art and are described, for example, in EP 2 663 892. Optical elements are also already available

Transformation of the intensity profile of a laser beam is known. For example, laser beams with a Gaussian shape can be generated using diffractive and/or refractive optics

Intensity profile is transformed into laser beams which have a top-hat-shaped intensity profile in one or more defined levels, such as a

Gauss-to-Top Hat Focus Beam Shaper from TOPAG Lasertechnik GmbH, see e.g.

DE102010005774A1. Such laser beams with top-hat-shaped intensity profiles are particularly attractive for laser material processing, especially when using

Laser pulses that are shorter than 50 ps, since with the essentially constant energy or

Power density allows particularly good and reproducible machining results to be achieved.

The laser radiation source (1) contained in the device according to the invention can be one

Intensity of 0.01 to 5 J/cm?, particularly preferably 0.1 to 2 J/cm?, very particularly preferably 0.1 to 0.5 J/cm?. Through the device according to the invention, the intensity of the

Laser radiation source can be flexibly selected in one area. The beam diameter plays no role in generating the interference pattern on the substrate, preferably a flat and/or transparent substrate. Due to the preferred arrangement of the optical

Elements in the beam path of the laser is not a unit for controlling the intensity of the

Laser beam necessary.

Suitable laser radiation sources include, for example, UV laser beam sources,

Laser beam sources (155 to 355 nm) containing green light (532 nm), diode lasers (typically 800 to 1000 nm) or laser beam sources operating in the near infrared (typically 1064 nm)

Emit radiation, in particular with a wavelength in the range from 200 to 650 nm

Wavelength. Lasers suitable for microprocessing are known to those skilled in the art

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application includes, for example, HeNe laser, HeAg laser (approx. 224 nm), NeCu laser (approx. 249 nm), LU102920

Nd:YAG laser (approx. 355 nm).

Optical elements

The present invention includes a number of optical elements. With these

The elements are prisms and lenses.

These lenses can be refractive or diffractive. Spherical, aspherical or cylindrical lenses can be used. In a preferred embodiment, cylindrical lenses are used. This makes it possible to see the overlap areas

Compress partial beams (also referred to herein as interference pixels) in one spatial direction and stretch them in another. If the lenses are not spherical/aspherical but cylindrical, this has the advantage that the beams can be deformed at the same time. This allows the processing spot (i.e. the one generated on the substrate

Interference pattern) is deformed from a point to a line that

Contains interference patterns. With sufficient energy from the laser, this line can be up to 10-15 mm long (and approximately 100 µm thick).

Spatial Light Modulators (SLM) can also be used to shape the beam.

The use of SLMs to spatially modulate the phase or intensity or the phase and intensity of an incident light beam is known to those skilled in the art. The

The use of Liquid Crystal on Silicon (LCoS)-SLM for beam splitting is described in the literature and is also conceivable in the device according to the invention. In addition, SLMs can also be used to focus the partial beams on the substrate.

Such an SLM can be controlled optically, electronically or acoustically.

All optical elements explained below are arranged in the beam path (3) of the laser. For the purposes of the invention, the beam path of the laser refers to the course of both the laser beam emitted by the laser radiation source and the course of the partial beams split by a beam splitter element. As the optical axis of the

However, the beam path (3) is understood to mean the optical axis of the laser beam emitted by the laser radiation source (1). Unless otherwise explained, all are optical

Elements arranged perpendicular to the optical axis of the beam path (3).

Beam splitter element (2)

There is a in the beam path (3) of the laser, behind the laser radiation source (1).

Beam splitter element (2). The beam splitter element (2) can be diffractive or refractive

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Be beam splitter element. For the purposes of the invention, a diffractive LU102920 is referred to

Beam splitter element is an optical element that contains micro- or nanostructures. For the purposes of the invention, a refractive beam splitter element refers to a transparent optical element, such as. B. a prism.

The beam splitter element (2) divides the emitted laser beam into at least 3, preferably at least 4, in particular 4 to 8, i.e. 4, 5, 6, 7 or 8 partial beams.

In a further embodiment, the beam splitter element (2) divides the emitted laser beam into at least 2, preferably at least 3 to 4, in particular 4 to 10, i.e. 4, 5, 6, 7, 8, 9 or 10 partial beams.

The beam splitter element (2) is along its optical axis, in particular in

Beam path of the laser beam emitted by the laser radiation source is freely movable. That is, it can be moved toward or away from the laser radiation source along its optical axis. The movement of the beam splitter element (2) changes this

Expansion of the at least 3 partial beams so that they hit a focusing element at different distances from one another. This allows the angle © at which the

Partial beams striking the substrate (5), preferably flat and/or transparent substrate, can be changed. This results in a seamless change in the structural period A when four partial beams are superimposed

A= A /2sin0 where) is the wavelength of the emitted laser beam.

Particularly preferably, the angle © at which the partial beams impinge on the substrate (5), preferably a flat and/or transparent substrate, is 0.1° to 90°.

The angle © is also dependent on the distances between the optical elements, in particular on the distance between the optical elements and the beam splitter element, and especially on the distance between the focusing element and the beam splitter element. Depending on the desired structural period, which is on or in the flat and/or transparent

Substrate is to be produced, the position of the beam splitter element can be adjusted or calculated so that the desired structure period can be set. The

Position of the optical elements comprised by the device, in particular the position of the focusing element in relation to the beam splitter element, is taken into account in such a way that if the distance between the optical elements is greater or smaller, the position of the

Beam splitter element can be adjusted accordingly.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

According to a preferred embodiment of the invention, the device also includes an LU102920

Measuring device, in particular a measuring device that works by means of a laser or an optical sensor, which is used to measure the position of the beam splitter element and, if necessary, the distance of the beam splitter element to the further optical

Elements, in particular the position of the focusing element is set up.

Furthermore, the device according to the invention can comprise a control device which is connected in terms of signals to the measuring device and which is in particular connected to a computing unit in such a way that the measured position of the beam splitter element is comparable to a first predetermined comparison value, the control device being set up in terms of programming in such a way that, if the Distance of the beam splitter element to the other optical elements, in particular to the position of the focusing element, is greater than the first predetermined comparison value, then via the control device

Control signal is generated, with which at least one position of an optical element is changed such that the desired structure period is generated on the substrate.

In this context, the method for producing a substrate with a periodic dot structure in the micro- or sub-micrometer range can also be used in particular

Step (a) includes the following steps: (i) measuring the position of the beam splitter element and, if necessary, the distance of the beam splitter element to the further optical elements, in particular to

Position of the focusing element, (ii) comparing the measured position of the beam splitter element with a first predetermined comparison value, and (iii) if the measured position of the beam splitter element is the distance of the

Beam splitter element to the other optical elements, in particular to

Position of the focusing element is greater than the first predetermined one

Comparative value is: changing the position of the optical element in such a way (in particular in relation to the other optical elements) that the desired structure period is generated on the substrate.

The laser beam can be divided in the beam splitter element (2) both by a partially reflective beam splitter element, for example a semi-transparent mirror, and by a transmissive beam splitter element, for example a dichroic prism.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In a preferred embodiment, the beam splitter element (2) has further LU102920

Beam splitter elements arranged downstream in the beam path of the laser. These beam splitter elements are arranged in such a way that they divide each of the at least three partial beams into at least two further partial beams. This allows a higher number of partial beams to be generated, which are directed onto the substrate, preferably a flat and/or transparent substrate, so that they interfere on the surface or inside the substrate. This allows the structure period of the interference pattern to be adjusted.

Focusing element (4)

Furthermore, in the beam path (3) of the laser, a focusing element (4) is arranged downstream of the beam splitter element (2), which is set up in such a way that the partial beams pass through it in such a way that the partial beams are on the surface or inside a substrate to be structured (5 ) interfere in an interference area. The

Focusing element (4) focuses the at least three partial beams in a spatial direction without focusing the at least three partial beams in the spatial direction perpendicular thereto.

For example, the focusing element (4) can be a focusing optical lens. For the purposes of the invention, focusing means bundling the at least three

Partial beams on the surface or inside a substrate, preferably a flat and/or transparent substrate.

The focusing element (4) can be freely movable in the beam path (3). According to a preferred embodiment of the present invention, the focusing element (4) is in

Beam path or fixed along the optical axis.

It is understood that the optical elements defined here are used, for example, for beam splitting and for aligning the partial beams in the direction of a device to be structured accordingly

Substrate can be arranged in a common housing.

In a preferred embodiment, the focusing element (4) is a spherical lens. The spherical lens is set up in such a way that the incident at least three partial beams pass through it in such a way that they interfere in an interference region on the surface or in the interior of the substrate (5) to be structured, preferably a flat and/or transparent substrate. The width of the interference region is preferably 1 to 600 μm, particularly preferably 10 to 400 μm, most preferably 20 to 200 μm. In this way, a high structuring rate, for example as defined herein, can be set at the same time.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In a particularly preferred embodiment, the focusing element (4) LU102920 is a cylindrical lens. The cylindrical lens is set up in such a way that the area in which the at least three partial beams overlap on the surface or in the interior of the substrate (5), preferably flat and/or transparent substrate, is stretched in a spatial direction. As a result, the area of the substrate on which the interference pattern can be generated takes on an elliptical shape. The semimajor axis of this ellipse can reach a length of 20 μm to 15 mm. This increases the area that can be structured during irradiation.

First deflection element (7)

In a particularly preferred embodiment, a deflection element (7), which is preferably arranged in the beam path (3) of the laser, is located in front of the focusing element (4) and after the beam splitter element (2). This deflection element (7) becomes

Expanding the distances between the at least three partial beams is used and can therefore also change the angle at which the partial beams impinge on the substrate (5), preferably a flat and/or transparent substrate. It is set up in such a way that it...

Divergence of the at least three partial beams is increased and thus the area in which the at least three partial beams interfere is moved away from the laser radiation source (1) along the optical axis of the beam path (3).

By expanding the distances between the at least three partial beams, in the sense of

Invention understood that the angle of the respective partial beams to the optical axis of the laser beam emitted by the laser radiation source (1) increases.

The expansion and the resulting deflection of the partial beams has the advantage that the partial beams can be focused more strongly by the focusing element (4). This results in a higher intensity in the area in which the at least three partial beams interfere on the surface or in the interior of the substrate (5), preferably a flat and/or transparent substrate.

Through the appropriate choice of the deflection element, a unit can be used to control the

Intensity of the laser beam can be dispensed with. In a preferred embodiment of the

In the device, a deflection element (7) is used that, by expanding the at least three partial beams, focuses the at least three partial beams on the

Substrate (5) allowed by means of a focusing element (4), the intensity of which

Interference points on the surface or inside the substrate, preferably flat and/or transparent substrate, without additional adjustment of the intensity

Laser radiation source (1) can be reached. This has the advantage of providing structuring

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application for the substrate to produce the periodic dot structure, LU102920 laser radiation sources with low intensity (power per area) can also be used, which means the optical

Elements are protected from wear.

Additional deflection element (6)

Furthermore, it can be provided that a further deflection element (6) is arranged in the beam path (3) of the laser radiation source (1) downstream of the beam splitter element (3), which deflects the partial beams in such a way that they emerge from the further

Deflection element (6) runs essentially parallel to one another. This allows the

The device can be set up in such a way that the processing point, i.e. the point in which the at least three partial beams on the surface or in the interior of the substrate, preferably flat and/or transparent substrate, interfere, when the

Beam splitter element in the beam path of the laser remains constant along its optical axis. The term “essentially parallel” is used in this document to mean:

Angular offset of between +15° and -15°, in particular only between +10° and -10°, very particularly preferably between +5° and -5° between the two partial beams, but in particular of course no angular offset, i.e. 0°, be understood.

The further deflection element (6) can be a conventional, refractive lens. Alternatively, the further deflection element (6) can also be designed as a diffractive lens (e.g. Fresnel lens). Diffractive lenses have the advantage of being significantly thinner and lighter, which simplifies miniaturization of the device disclosed herein.

By appropriately selecting the refractive indices of the optical elements (4), (6) and (7), the distances between optical elements and substrate, as well as the structure period

MA can be set. All optical elements with the exception of the beam splitter element (2) can preferably be fixed within the beam path (3) of the laser. This particularly preferred embodiment therefore offers the advantage that to adapt the

Interference range or the interference angle only one element, namely that

Beam splitter element (2) must be moved. This saves steps when setting up the device, such as calibrating the device to the desired structure period. Of

Furthermore, a fixed setting, i.e. preferably all optical elements are fixed within the beam path (3) of the laser, bends the optical elements

Wear and tear.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Polarization element (8) LU102920

In a further embodiment, (7) is located behind the deflection element, particularly preferably in a structure with two deflection elements (6), behind the further one

Deflecting element (6), and in front of the focusing element (4) a polarization element (8) in each of the beam paths of the at least 3 partial beams. The polarization elements can modify the polarization of the partial beams relative to one another. This allows the resulting interference pattern, which has the at least 3 partial beams on the surface or inside

Image, modify the volume of a substrate, preferably a flat and/or transparent substrate.

In particular, the interfering partial beams can therefore be non-polarized, linearly polarized, circularly polarized, elliptically polarized, radially polarized or azimuthally polarized.

Optical element for beam shaping

In a further embodiment, the laser radiation source (1) has a radiation profile that corresponds to a Gaussian profile, as described above. In such an embodiment, a further optical element for beam shaping can be located behind the laser radiation source (1) and in front of the beam splitter element (2). This element is used to...

To align the radiation profile of the laser radiation source with a top hat profile.

An optical element with a concave, parabolic or planar reflecting surface can also be provided in the device according to the invention, the optical

Element, for example, rotatable about at least one axis or along the

Beam path (3) is designed to be displaceable. This makes it possible, if necessary, to use an additional focusing element (4) or another one positioned in the beam path (3).

Deflection element (6) can be dispensed with. For example, this optical element

Laser beams or partial laser beams are directed onto the surface of the focusing element (4) or another focusing optical element before the beams are used

Formation of structural elements reach the substrate to be structured.

Alternatively, for example, at least one optical element can be provided with a concave parabolic or planar reflecting surface, which is designed to be rotatable about at least one axis or displaceable along the beam path (3), for example, this optical element being the first deflection element (7) and the further Deflection element (6) is positioned downstream in the beam path. For example, the partial beams can be deflected in the beam path (deflection mirror) or

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application can be focused in the beam path in such a way that the substrate to be structured during LU102920

Processing can be positioned in a fixed position (so-called focusing mirror or galvo mirror (laser scanner) (9)).

An embodiment that includes a polygon scanner is also conceivable. In this embodiment, at least one optical element comprises a periodically rotating prism, preferably a periodically rotating mirror prism, in particular a polygon mirror or polygon wheel, as well as a periodically rotating prism

Focusing element (4) arranged downstream of the prism in the beam path. The focusing element is set up in such a way that the partial beams pass through it in such a way that the partial beams are on the

Surface or inside a substrate (5) to be structured in one

Interference area interfere. In a preferred embodiment, the optical includes

Element furthermore at least another deflection element, for example a reflective one

Deflecting element for deflecting the partial beams in the beam path. The at least one further deflection element can be arranged upstream and/or downstream of the periodically rotating prism in the beam path. The at least one further deflection element is the

Focusing element arranged upstream in the beam path.

Such a structure advantageously allows a surface to be scanned quickly

Substrate, so that a high structuring rate of up to 3 m?/min, especially in the

Range from 0.1 to 2 m?min, particularly preferably in the range from 0.05 to 1 m?min, very particularly preferably in the range from 0.1 to 0.9 m?min can be achieved. The exact

Structuring rate depends in particular on the available laser power. With future technologies that have higher laser power, even higher structuring rates can be achieved.

Holding device for the substrate

In a further embodiment, the substrate (5), preferably a flat and/or transparent substrate, is movable in the xy plane. By moving the substrate (5), preferably a flat and/or transparent substrate, in the xy plane, a flat

Processing can be ensured using laser interference structuring. This is done in

Each processing step (i.e. laser pulse that hits the substrate to be structured) generates a so-called interference pixel, which has a size D depending on the angle of incidence and the

Intensity distribution of the laser beam, as well as the focusing properties of the optical

has elements. The distance between the different interference pixels

Pixel density Pd is determined by the repetition rate of the laser radiation source (1). Is the

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Pixel density Pd is smaller than the size of the interference pixels D, so there is a flat, homogeneous LU102920

Editing possible.

Proceedings

The present invention also includes a method for producing a substrate, preferably a flat and/or transparent substrate, with a periodic dot structure in the micro- or sub-micrometer range by means of laser interference structuring.

In the sense of the invention, the method for producing a structured substrate, preferably a flat and/or transparent substrate, with a periodic dot structure in the micro- or sub-micrometer range by means of laser interference structuring, comprises the following

Steps:

A substrate (5), preferably a flat and/or transparent substrate, is provided, which is located on a holding device. A laser beam is emitted from a laser radiation source (1). The laser beam is divided by a beam splitter element (2) and at least three, particularly preferably four, partial beams. The partial rays arrive

Focusing element (4), which focuses (bundles) the at least three, particularly preferably four partial beams on the surface or inside the substrate (5), preferably flat and/or transparent substrate, so that the partial beams on the surface or inside the Substrate interfere constructively and destructively. Thus, a periodic dot structure in the micro- or sub-micrometer range is created on the surface or in the

Interior of the substrate (5), preferably flat and/or transparent substrate

Laser interference processing generated. The method is characterized in that the at least three partial beams are superimposed in such a way that a 2D pattern is created.

The point structures created in this way are in the form of periodically arranged, inverse ones

Cones are formed, the distance between the vertices (i.e. height center or centers of the elevations) being arranged on a statistical average in the range from 50 nm to 50 μm, preferably in the range from 50 nm to 20 μm, more preferably in the range from 100 nm to 1,000 nm, particularly preferably in the range from 100 nm to 600 nm.

The inventors of the present invention have further discovered that, in addition to the periodicity, the structure depth (i.e. the depth of the inverse pegs, measured from their saddle point of the recess to the apex) also has an influence on the

Have anti-reflection properties (as defined herein). For example, there is structural depth

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application or profile depth of the inverse pins (elevations and depressions) in the statistical average in LU102920

Range from 5 nm to 100 nm, preferably in the range from 5 nm to 75 nm.

According to a preferred embodiment of the present invention, the inverse

Have a structure depth in the range from 5 nm to 200 nm, particularly preferably in the range from 5 nm to 150 nm, very particularly preferably 10 nm to 100 nm.

Preference is given to using a device for producing a structured substrate (5), preferably a flat and/or transparent substrate, which comprises two deflection elements (6), (7). The deflection elements (6), (7) are in the beam path (3) of the laser between

Beam splitter element (2) and the focusing element (4) are arranged. The deflection elements (6), (7) serve to expand the diffraction angle of the at least three, particularly preferably four, partial beams by interfering on the surface or inside the substrate (5), preferably flat and/or transparent substrate. By setting the

Distances between the optical elements can be ensured to change the

Structure period only the beam splitter element (2) has to be movable along its optical axis. This enables easier adjustment processes during machining.

In a particularly preferred embodiment, a transparent material is provided as a flat substrate. Due to the translucency of the transparent material, laser interference processing is possible, preferably with a

Embodiment of the above-mentioned device inside the substrate possible.

In a preferred embodiment, a device is used for producing a structured substrate, preferably a flat and/or transparent substrate, which uses a pulsed laser radiation source (1). In a particularly preferred one

Embodiment, a device is used for producing a structured substrate, preferably a flat and/or transparent substrate, which has a

Holding device for the substrate, which is freely movable in the xy plane, perpendicular to the beam path (3) of the laser beam emitted by the laser radiation source (1).

The pixel density Pd, i.e. the distance in the a, can be determined via the frequency of the laser radiation source (1), f, and the speed of movement of the holding device, v

Interference pixels with the width D can be applied to the substrate, preferably flat and/or transparent substrate, set to: —v

Pd = If

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

If the width of the interference pixel, D, is greater than the pixel density Pd, then LU102920 neighboring interference pixels overlap in one area. This area is known to the expert

Pulse overlap, OV, is known. It can be calculated as: ov = (D — Pd) /p

In a preferred embodiment, in the method for producing a structured substrate, preferably a flat and/or transparent substrate, Pd is smaller than D. The resulting pulse overlap OV leads to multiple irradiation of the

Substrate, preferably flat and/or transparent substrate. In this way, non-textured surfaces can preferably be avoided.

In a particularly preferred embodiment, in the method for producing a structured substrate, preferably a flat and/or transparent substrate, the same interference pixels are irradiated several times. This makes it possible to increase the depth of the resulting microstructures.

The advantage of a structured substrate, preferably a flat and/or transparent substrate, produced by such a method is the high regularity of the periodic point structures produced with structure dimensions in the micro or

Submicron range. A periodic point structure created in this way with dimensions in

Micron or submicron range preferably has a coefficient of variation (a value obtained by dividing the standard deviation by the average value) of

Pin cross section of 15% or less, more preferably 10% or less, even more preferably 5% or less.

Multiple irradiation of a substrate is particularly suitable for producing hierarchical structures. Multiple irradiation of the same interference pixel causes at least partial melting of the substrate material, with the

Structuring process, i.e. when a laser pulse hits, a wave structure forms as a result of the appearance of a high intensity area. This forms the

Structuring, especially the wave structure, through a self-organization process. In particular, the wave structure superimposes a periodic point structure in the micro- or sub-micrometer range, which can be generated using laser interference structuring.

A hierarchical structuring in a substrate can thus be created in one process step. According to a preferred embodiment of the invention, this therefore takes place

Multiple irradiation, preferably 2-fold to 400-fold, in particular 20-fold to 300-fold, particularly preferably 50-fold to 200-fold irradiation of the same interference pixel on the substrate, whereby a wave structure (as defined herein) is formed,

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application in particular a periodic point structure is formed from superimposed structures LU102920, with at least one structure having dimensions in the submicrometer range, in particular a quasi-periodic wave structure, and with at least one

Structure is formed from inverse cones. The time offset between the individual pulses is particularly preferred in the range of the pulse duration of the laser pulse, preferably in

Range from 1fs to 100ns, particularly preferably in the range from 10fs to 1ns, very particularly preferably in the range from 10fs to 10ps.

A hierarchical structuring refers to a structure in which a first

Structure with dimensions in the micro- or sub-micrometer range, which a

Interference pattern corresponds to, is overlaid by another structure, which

Has dimensions that are below the dimensions of the first structure and which is formed by a self-organization process. They are preferably located

Dimensions of the further structure, which is formed by a self-organization process, in the range from 1% to 30% of the dimensions of the first structure, which corresponds to an interference pattern.

There are numerous technical areas of application for hierarchical structures, such as in the area of producing substrates with hydrophobic or superhydrophobic as well as hydrophilic or superhydrophilic surfaces and substrates with anti-icing or anti-icing.

Fogging properties in addition to the substrates mentioned at the beginning

Anti-reflection properties. A method for producing such hierarchical structures, as described herein, advantageously enables the precise adjustment of the

Process parameters for the structure dimensions through a suitable selection of the

Laser radiation source and a corresponding displacement of the beam splitter element in

Laser beam path.

In addition, the method defined herein makes it possible to provide a substrate with hierarchical structures using the same device and in the same process step, while conventional processes proceed successively, i.e. are not able to create a first structure with dimensions in the micro-scale at the same time. or

Submicrometer range, which corresponds to an interference pattern, and another

To create a structure that is formed through a self-organization process.

A displacement of the substrate to be structured, preferably flat and/or transparent substrate, in the laser beam is possible due to the relatively large movements

Mass comparatively complex and slow. It is therefore advantageous for the substrate, preferably a flat and/or transparent substrate, to be stationary during processing

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application and to realize the flat structuring of the substrate by using the LU102920

Focusing the partial beams on the surface or the volume of the substrate

Manipulation of the partial laser beams with optical elements (focusing mirrors or galvanizing

Mirror (laser scanner)) is effected in the beam direction. Since the masses moved are relatively small, this can be done with much less effort and much faster.

The substrate is preferably arranged in a stationary manner during the process.

The surface structuring of the substrate is of course also possible in principle by displacing the substrate in the laser beam.

The periodic structures in the micro- and/or nanometer range generated by means of the method and device disclosed herein have such structured structures

Substrate anti-reflection properties. This is ensured by the fact that light that hits the substrate is reflected less or is reflected at such a shallow angle that it does not appear “disturbing” when the material surface is viewed normally.

The invention therefore also covers a structured substrate with anti-reflection properties, which comprises a periodic dot structure in the micro- or sub-micrometer range, the periodic dot structure being formed from inverse cones, the inverse

Cones periodically with a distance based on their saddle point or center point

In the range from 50 nm to 50 μm, preferably in the range from 50 nm to 20 μm, more preferably in the range from 100 nm to 1,000 nm, particularly preferably in the range from 100 nm to 600 nm, are arranged to one another.

According to a preferred embodiment of the invention, the structured substrate is through

Processing obtained using a method as defined herein.

The present invention also relates to a method for producing a substrate with a periodic dot structure in the micro- or sub-micrometer range

Laser interference structuring, in particular by a method disclosed herein, comprising the following steps: a) applying a first pulse to the surface of a substrate (5), preferably by a device as defined herein, which has a first

Interference pixels are generated on the surface of the substrate (5) or in the substrate (5),

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application b) applying a second pulse to the surface of a substrate (5), LU102920, preferably by a device as defined herein, which has a second

Interference pixels generated on the surface of the substrate (5) or in the substrate (5), the first and second interference pixels each independently comprising a periodic point structure with dimensions in the micro- and sub-micrometer range, characterized in that the offset between the second interference pixel and the first interference pixel is in the range of 10% <= x < 50% of the interference period.

It goes without saying that the and everyone

This makes it particularly advantageous to produce a structuring on the substrate, in particular on a transparent substrate, which has anti-glare properties.

For the purposes of the invention, glare means the reflection of light from a person

Light source (e.g. the sun) on a transparent substrate, such as a window or screen, which can make it difficult to see what is happening on the

detect screen.

These glare effects can be reduced with the help of an anti-glare treatment of the surfaces (typically produced by coatings in the prior art). An anti-glare

Structure scatters incident light on the surface so that reflections can be significantly reduced.

According to a preferred embodiment of the invention, the period of the dot structure of the first interference pixel and the period of the second interference pixel are identical.

In addition, it can be provided that after step b) a third or each additional

Pulse is applied to the surface of a substrate (5), preferably by a device as defined herein, the third or each further interference pixel being a periodic one

Dot structure with dimensions in the micro- and sub-micrometer range, the third or each further pulse having a third or further interference pixel on the

Surface of the substrate (5) or generated in the substrate (5), the third or

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application additional interference pixels in relation to the second or previous interference pixel a LU102920

has an offset in the range of 10% =< x < 50% of the interference period,

According to a preferred embodiment, the offset of the interference period is one

Interference pixel to the previous interference pixel in at least one

Spatial direction, in particular in all spatial directions of the substrate surface, is formed uniformly by the method according to the invention.

Structured substrate

The inventors have discovered that substrates patterned primarily by a device or method disclosed herein exhibit distinctive antireflection properties. The present invention therefore also relates to a structured substrate with anti-reflection properties, as defined herein, which comprises a periodic dot structure in the micro- or sub-micrometer range, the periodic dot structure being formed in particular from an inverse cone structure (also referred to herein as inverse cone), the inverse Cones periodically with a

Distance based on their saddle point or center in the range from 50 nm to 50 μm, preferably in the range from 50 nm to 20 μm, more preferably in the range from 100 nm to 1,000 nm, particularly preferably in the range from 100 nm to 600 nm .

The periodic point structure created in this way has the property that, depending on its

Structural dimension incoming electromagnetic radiation with wavelengths in

The range from 10 nm to 1 mm is increasingly transmitted, or through the periodic

Structures can be diffracted so that there is reduced reflection on the surface of the

Substrate results. If the period of the periodic point structures generated is in the range of the wavelength of the incident electromagnetic wave, it will be at the

Surface of the substrate diffracted. Is the period of the generated periodic

If a point structure is smaller than the wavelength of the incident electromagnetic wave, it will be transmitted.

The periodic dot structure is preferably designed in such a way that the structured substrate receives electromagnetic radiation with a wavelength of more than 550 nm with a periodic dot structure of less than 1,000 nm, preferably more than 500 nm with a periodic dot structure of less than 750 nm particularly preferably with a periodic point structure of less than 600 nm transmitted by more than 450 nm. Depending on the structural depth of the inverse tenons,

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application in particular wavelengths in the red and/or yellow light spectrum, in the green LU102920

Transmit light spectrum into the substrate up to the blue light spectrum.

The refractive index of the structured substrate is generated by the periodic

Point structure gradually. It decreases over the height of the structure, so no clear

Air-medium transition exists. This results in increased transmission of incident electromagnetic waves with a wavelength greater than that

Structure period of the generated point structure, and for diffraction of incident electromagnetic waves with a wavelength in the range of the structure period of the generated point structure.

Due to the very small structural dimensions that can be produced, the device disclosed herein and the method disclosed herein are suitable for producing a

Anti-reflection structure also for creating surfaces with hydrophobic and/or superhydrophobic as well as hydrophilic and/or superhydrophilic properties.

Hydrophobic properties depend on both the chemical and the

Surface quality, in particular the surface roughness, of a substrate. The

Inventors have now surprisingly discovered that the invention

Methods in particular hydrophobic substrates can be obtained by introducing structures in the micrometer and submicrometer range, in particular superimposed structures (as defined herein) substrate surfaces which have superhydrophobic and self-cleaning properties. It is particularly preferred

Substrates with superhydrophobic properties to substrates with a hierarchical

Surface structuring. Hierarchical surface structuring means that it is a surface on which there are regular structures

Dimensions are in the micrometer range, which in turn are due to their

Surface has a structure with dimensions in the submicrometer range. Such a hierarchical structuring can lead to high surface roughness.

The inventors have also discovered that substrates that have been patterned primarily by a device or method disclosed herein are characterized by pronounced hydrophobic properties on the surface of a substrate.

Using the apparatus and method disclosed herein for generating

Anti-reflection structures with dimensions in the micro- and sub-micrometer range are also a structuring for producing a surface texture, in particular a

Surface roughness is possible on the surface of a substrate, which results in the substrate having hydrophobic or superhydrophobic properties.Hydrophobic

Material properties can be created by using direct

Laser interference structuring is a structure with dimensions in the micro and/or

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Submicrometer range is generated. In a preferred embodiment, an LU102920 is initially used

Structure with dimensions in the micrometer range is created on the surface. A structure is then created by moving the beam splitter element in the beam path of the laser

Dimensions in the submicrometer range are generated on the surface of the first structure, with multiple irradiation of the substrate preferably taking place. The hierarchical structure created in this way has hydrophobic or superhydrophobic properties.

To produce a substrate with hydrophobic properties, it is also conceivable that only a structure with dimensions in the micro- or sub-micrometer range is produced without the beam splitter element being moved in an intermediate step.

Advantageously, using the same method and based on the same device, substrates with hydrophobic and/or superhydrophobic properties can be produced in a technically easily realizable manner by creating a periodic dot structure in the

Micro or submicrometer range and / or a periodic point structure with a hierarchical structure in the micro and submicrometer range is generated. By the

Moving the beam splitter element is at least twofold, but also arbitrary

Number of further structuring on the surface of the substrate without any further

Changing the structure, for example without replacing optical elements or

Moving the substrate, feasible. This increases both the precision in the alignment of the structures and the speed of the process compared to conventional methods or devices.

The inventors have a connection between the surface quality of a

substrate and ice formation on its surface. In particular, so-called anti-icing properties can be created if the structure size is at the

Surface of a substrate is sufficiently small. Research has shown that a substrate with superhydrophobic properties can also have anti-icing properties.

For the purposes of the invention, anti-icing properties are to be understood as meaning that on the

No or only very little water freezes on the surface of a substrate

Property is due to the surface quality, in particular the surface roughness.

Such a substrate can be advantageous in the field of aerospace, wind turbines, automotive components or even telecommunications and

Antenna technology can be used to protect exposed components from freezing.

The inventors have further discovered that substrates patterned primarily by an apparatus or method disclosed herein

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application characterized by pronounced hydrophilic properties on the surface of a substrate LU102920. By means of the device and the method disclosed herein for producing anti-reflection structures with dimensions in the micro- and sub-micrometer range, structuring for producing a surface texture, in particular a

Surface roughness on the surface of a substrate is possible, which leads to the substrate having hydrophilic or superhydrophilic properties.

Hydrophilic material properties can be created by using direct

Laser interference structuring is a structure with dimensions in the micro and/or

Submicrometer range is generated. In a preferred embodiment, initially one

Structure with dimensions in the micrometer range is created on the surface. A structure is then created by moving the beam splitter element in the beam path of the laser

Dimensions in the submicrometer range are generated on the surface of the first structure, with multiple irradiation of the substrate preferably taking place. The hierarchical structure created in this way has hydrophilic or superhydrophilic properties.

To produce a substrate with hydrophilic properties, it is also conceivable that only a structure with dimensions in the micro- or sub-micrometer range is produced without the beam splitter element being moved in an intermediate step.

Advantageously, using the same method and based on the same device, substrates with hydrophilic and/or superhydrophilic properties can be produced in a technically easily realizable manner by creating a periodic dot structure in the

Micro or submicrometer range and / or a periodic point structure with a hierarchical structure in the micro and submicrometer range is generated. By the

Moving the beam splitter element is at least twofold, but also arbitrary

Number of further structuring on the surface of the substrate without any further

Changing the structure, for example without replacing optical elements or

Moving the substrate, feasible. This increases both the precision in the alignment of the structures and the speed of the process compared to conventional methods or devices.

The inventors have a connection between the surface quality of a

Substrate and the formation of condensation, especially in the form of fog or

Fog, detected on the surface. In particular, so-called anti-

Fogging properties are created when the feature size on the surface of a

Substrate is sufficiently small. Research has shown that a substrate with superhydrophilic properties can also have anti-fogging properties.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

For the purposes of the invention, anti-fogging properties are to be understood as meaning that on the LU102920

On the surface of a substrate, no or very little water condenses in the form of drops, and this property depends on the surface condition, in particular

due to surface roughness.

Such a substrate can be advantageous in the field of aerospace, in the field of

Automotive components or telecommunications and antenna technology are used to protect exposed components from fogging.

In one embodiment of the invention, the method and apparatus disclosed herein are suitable for producing a substrate having a periodic

Point structure in the micro- or sub-micrometer range, which is achieved by means of

Laser interference structuring was created, includes and which is caused by

anti-reflection properties. In the sense of the invention refer

Anti-reflection properties here refer to the increased transmission or diffraction of incident electromagnetic radiation with wavelengths in the visible range

Light, in particular with wavelengths in the range from 400 nm to 700 nm. The substrate is characterized in that the periodic point structure it comprises preferably has dimensions in the submicrometer range, particularly preferably in the

Nanometer range. The dimensions of the periodic point structure are particularly preferred in the range of the wavelength of electromagnetic radiation in the range of visible light. The dimensions of the periodic dot structure are preferably in the range from 630 nm to 700 nm for transmitting or diffracting red

Light, in the range from 590 nm to 630 nm for transmitting or diffracting red and orange light, in the range from 560 nm to 590 nm for transmitting or diffracting red, orange and yellow light, in the range from 500 nm to 560 nm for transmitting or bending red, orange, yellow and green light, in the range from 475 nm to 500 nm for transmitting or bending red, orange, yellow, green and turquoise light, in the range from 450 nm to 475 nm for transmitting or diffracting red, orange, yellow, green, turquoise and blue light, in the range from 425 nm to 450 nm for transmitting or diffracting red, orange, yellow, green, turquoise, blue and indigo Light, in the range from 400 nm to 425 nm

Transmitting or bending red, orange, yellow, green, turquoise, blue, indigo and violet light. Thus, by changing the

Dimensions of the periodic dot structure control the anti-reflection properties of the substrate.

In one embodiment of the invention, the method and apparatus disclosed herein are suitable for producing a substrate having a periodic

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Point structure in the micro- or sub-micrometer range, which is determined using LU102920

Laser interference structuring was created, includes and which is caused by

anti-reflection properties. In the sense of the invention refer

Anti-reflection properties here refer to the increased transmission or diffraction of incident electromagnetic radiation with wavelengths in the invisible range

Light, especially in the range of infrared radiation, or thermal radiation, especially with wavelengths in the range from 780 nm to 1 mm. The substrate is characterized in that the periodic dot structure it encompasses is preferably

Has dimensions in the micrometer range. The heat transmission is advantageous

Substrate can be adjusted by changing the dimensions of the periodic dot structure.

In one embodiment of the invention, the method and apparatus disclosed herein are suitable for producing a substrate having a periodic

Point structure in the micro- or sub-micrometer range, which is achieved by means of

Laser interference structuring was created, includes and which is caused by

anti-reflection properties. In the sense of the invention refer

Anti-reflection properties here refer to the increased transmission or diffraction of incident electromagnetic radiation with wavelengths in the invisible range

Light, especially in the range of ultraviolet radiation (IV radiation), especially with

Wavelengths in the range from 100 nm to 380 nm. The substrate is characterized in that the periodic dot structure it comprises preferably has dimensions in

Nanometer range. A substrate structured in this way can advantageously be used in areas where protection from UV radiation is necessary.

In a further embodiment of the invention, the method disclosed herein and the device disclosed herein are suitable for producing a substrate which is hierarchical

Structures which were generated by means of laser interference structuring by multiple irradiation of the same interference pixel, which are characterized by hydrophobic or superhydrophobic properties. The hydrophobic or superhydrophobic properties are due to the fact that structures with dimensions in the micro- or sub-micrometer range, in particular hierarchical structures

Dimensions in the micro and submicrometer range the wetting angle of

Liquids on substrates change in such a way that it becomes larger. A larger wetting angle means that liquids hitting the surface do not wet it well and instead roll off it. A substrate treated in this way has self-cleaning and water-repellent properties. Particularly suitable

Materials for such a structured substrate are materials that already have hydrophobic properties, e.g. metal or polymer surfaces.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In a further embodiment of the invention, the method LU102920 disclosed herein and the device disclosed herein are suitable for producing a substrate which is hierarchical

Structures which were created using laser interference structuring by multiple irradiation of the same interference pixel, which are characterized by anti-lcing, i.e. the

Formation of ice layers prevents properties. The anti-icing

Properties are based on the fact that structures with dimensions in the micro or

Submicrometer range, in particular hierarchical structures with dimensions in the micro and submicrometer range, change the wetting angle of liquids on substrates in such a way that it becomes larger. The structured substrate thus has hydrophobic or superhydrophobic properties. A larger wetting angle means that liquids hitting the surface do not wet it well and instead roll off it. This also makes it more difficult for ice layers to deposit on the surface. Particularly suitable materials for such a structured substrate are materials that already have hydrophobic properties, for example metal or

polymer surfaces.

In a further embodiment of the invention, the method disclosed herein and the device disclosed herein are suitable for producing a substrate which is hierarchical

Structures which were generated by means of laser interference structuring by multiple irradiation of the same interference pixel, which are characterized by hydrophilic or superhydrophilic properties. The hydrophilic or superhydrophilic properties are due to the fact that structures with dimensions in the micro- or sub-micrometer range, in particular hierarchical structures

Dimensions in the micro and submicrometer range the wetting angle of

Change liquids on substrates in such a way that it becomes smaller. A smaller wetting angle means that liquids hitting the surface wet it very well and no droplets form. Instead, uniform wetting is achieved, which does not impair the transparency of the substrate. Particularly suitable materials for such a structured substrate are materials that already have hydrophilic properties, e.g. glass surfaces.

In a further embodiment of the invention, the method disclosed herein and the device disclosed herein are suitable for producing a substrate which is hierarchical

Structures which were generated by means of laser interference structuring by multiple irradiation of the same interference pixel, which are characterized by anti-fogging, i.e. non-fogging properties. The anti-fogging properties are based on the fact that structures with dimensions in the micro- or sub-micrometer range, in particular hierarchical structures with dimensions in the micro- and sub-micrometer range

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In the submicrometer range, the wetting angle of liquids on substrates can be changed in such a way that it becomes smaller. The structured substrate thus has hydrophilic or superhydrophilic properties. A smaller wetting angle means that liquids hitting the surface wet it very well and there is no

Drop formation occurs. Instead, a uniform wetting is brought about, which

Transparency of the substrate is not affected. Particularly suitable materials for such a structured substrate are materials that are already hydrophilic

have properties, e.g. glass surfaces. A substrate structured in this way can be advantageous in the areas of automotive, aerospace technology, but also in general

Glazing is used in building technology.

In one embodiment of the invention, the method and apparatus disclosed herein are suitable for producing a substrate having a periodic

Point structure in the micro- or sub-micrometer range, which is achieved by means of

Laser interference structuring was created, which includes an increased

Has surface roughness. The increased surface roughness is based on the fact that the surface texture is caused by the periodic dot structure introduced into the substrate

Micro or submicrometer range is changed, in particular that the surface of the substrate increases and increases due to the introduced periodic dot structure

Has depressions. In particular, increased surface roughness can be achieved by forming a substrate using the method and device described herein with hierarchical structures having dimensions in the micro- and

Submicrometer range using laser interference structuring through a

Multiple irradiation of the same interference pixel is structured. One edited like this

Substrate can be used advantageously in the area of manufacturing, for example to increase the static friction and/or sliding friction between technical components, or in the

Medical technology to increase the adhesion of cells to a foreign surface.

In one embodiment of the invention, the method and apparatus disclosed herein are suitable for producing a substrate having a periodic

Point structure in the micro- or sub-micrometer range, which is achieved by means of

Laser interference structuring was created, which has an increased surface in the

Compared to an unstructured substrate with the same external dimensions.

The periodic dot structure in the micro- or sub-micrometer range contributes to the surface of the substrate increasing in proportion to the density of the interference regions per interference pixel. In particular, an increased surface can be achieved compared to an unstructured substrate with the same external dimensions by using a

Substrate using the method and methods described herein

Device with hierarchical structures with dimensions in micron and submicron

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Area using laser interference structuring through multiple irradiation of the same LU102920

Interference pixels are structured. A substrate processed in this way is advantageous in technical applications

Can be used in areas that require a high level of heat transport, as the increased surface provides a greater capacity for heat exchange compared to an unstructured substrate with the same external dimensions. Of

Furthermore, a substrate processed in this way can be used in the field of electrical connection technology to reduce contact resistance, since the increased surface in the

Compared to an unstructured substrate with the same external dimensions

Contact points between materials to be contacted can be produced. In addition, a substrate structured in this way can be used in the field of battery technology, in particular for

Structuring the anode and cathode, as the increased surface area provides more capacity compared to an unstructured substrate with the same external dimensions

There is an exchange of charge carriers between the metal of the electrodes.

Furthermore, the method disclosed herein and the device disclosed herein are suitable for producing a substrate comprising a periodic dot structure

Dimensions in the micro- or sub-micrometer range, which provides antibacterial (antiseptic)

Has properties. In a preferred embodiment, the periodic

The point structure has dimensions that are significantly larger, at least 10% to 30% larger, than the bacteria deposited on it. This will make them on the

Bacteria depositing on the surface are isolated and thus rendered harmless. In a particularly preferred embodiment, the periodic point structure has

Dimensions that are significantly smaller, at least 10% to 30% smaller, than the bacteria deposited on it. This prevents the bacteria from sticking to the surface

Surface is not possible and the surface is therefore kept sterile.

A structured substrate produced by the method and device disclosed herein is also suitable for further processing by means of a further coating process, wherein the substrate can receive a physical and/or chemical coating. Such a coating allows them to...

Properties of the structured substrate, for example the anti-reflection properties and/or hydrophilic and/or hydrophobic properties, are enhanced. That is conceivable

Applying a chemical spray coating and/or applying a

Coating using chemical vapor deposition and/or sputtering.

According to a preferred embodiment of the present invention, this includes structured

Substrate is a dot structure formed from a first and a second interference pixel, the first and second interference pixels each being independent

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application for a periodic dot structure with dimensions in the micro and submicrometer LU102920

Include area, wherein the first interference pixel and the second interference pixel are arranged superimposed on one another in such a way that the offset between the second

Interference pixel and the first interference pixel in the range of 10% < x < 50%, in particular in the range of 20% = < x < 50%, particularly preferably in the range of 25% = x < 45% of the interference period. This can be particularly advantageous in particular with the dimensions of the point structures defined herein (regardless of their area of application) on the substrate, in particular on a transparent one

Substrate a structuring can be created that has anti-glare properties.

It has been shown that a substrate structured in this way (with structure sizes as defined herein) has anti-glare properties.

According to a preferred embodiment of the invention, the periodic dot structure is designed in such a way that at least a third interference pixel or one that follows the previous interference pixel is arranged superimposed on the first and second or on the previous interference pixel, the offset between the third or each further interference pixel and the second or the previous interference pixel in the range of 10% <= x <50%, in particular in the range of 20% =< x <50%, particularly preferably in the range of 25% =< x < 45% of

Interference period lies.

According to a preferred embodiment, the offset of the interference period is one

Interference pixel to the previous interference pixel in at least one

Spatial direction, in particular uniformly formed in all spatial directions of the substrate surface.

Use of the structured substrate

The structured substrate with anti-reflection properties defined here is used, for example, in photovoltaic systems, whereby the efficiency of these photovoltaic systems can be significantly increased by introducing anti-reflective properties. A major challenge in the area of photovoltaic systems is the large losses due to the reflection of the sun's rays. Cause on average

Reflections 40% energy/power losses per system. The efficiency of

Photovoltaic systems must be continually improved accordingly. One of the most promising approaches is the reduction of reflection using

Anti-reflective coatings and/or texturing of the surface. The use of the herein

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application simplifies, accelerates and improves the treatment of LU102920

Surfaces.

It is also known that monitors and screens are often placed in fixed locations and are therefore susceptible to unfavorable lighting, which can lead to visibility problems

viewer. Although there are fundamental ways to minimize this effect, these approaches are not widely used because they tend to...

Relieving symptoms rather than specifically solving the problem. The structured defined herein

Substrate with anti-reflection properties is, for example, ideal for application or integration in the display area, for example in the form of anti-reflection glazing

Monitors, screens and displays.

Another area of application opens up in the area of anti-reflective coating

Glass fibers, which ensure higher transmission rates and minimize back reflections. The method disclosed herein is therefore ideal for structuring glass fibers, so that the glass fiber structured in this way offers a further application example for a structured substrate with anti-reflection properties as defined herein. From the present one

The invention therefore also includes the use of a structured substrate as defined herein

Component of glass fibers included.

In addition, the inventors have discovered that the method for structuring window panes defined herein (as another example of a

anti-reflection glazing). For example, the structured substrates disclosed herein can be in the form of anti-reflection glazing or as a foil

House facades, preferably flat and/or transparent substrates, are used as heat-insulating glazing, which, for example, protects against concentrated solar radiation through curved house facades and for better

Thermal insulation of buildings can be used.

In addition, a reduction in reflection from microscopes and telescopes can help

Increase the contrast of the images recorded with it, thereby increasing the efficiency and use of these optical devices. This is therefore also part of the present invention

Use of a structured substrate defined herein as an optical element with a periodic point structure in the micro- or sub-micrometer range in optical devices, such as microscopes and telescopes, for which the beam guidance, beam shaping,

Beam bundling and/or beam focusing are essential.

It is also useful for the structured substrate defined herein to be used as a negative form (so-called master), for example within an embossing process for indirect application or

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

To create structures on a different substrate. For example, LU102920 this is relevant for roll-to-roll processes where using a hot or UV

Embossing process structures from a so-called master (usually metal such as nickel) to one

Polymer film (e.g. PET) can be transferred in a continuous process. So can on others

Substrates the inverse structures in high throughput as periodic point structures in

Micro or submicrometer range can be generated.

The device according to the invention and the method according to the invention also offer the possibility of producing a substrate with hydrophobic or superhydrophobic substances over a large area without great technical effort. A substrate structured in this way has a wide

Range of applications in areas in which the self-cleaning properties of hydrophobic and/or superhydrophobic substrates are desired, for example in the area of

Automotive components, displays or glazing, but also in the aviation sector

Antenna technology.

The device according to the invention and the method according to the invention also offer the possibility of producing a substrate with hydrophilic or superhydrophilic substrates without great technical effort. A substrate structured in this way has a wide

Range of applications in areas in which the homogeneous wetting properties of hydrophilic and/or superhydrophilic substrates are desired, for example in the area of

Automotive components, displays or glazing, but also in the aviation sector

Antenna technology.

Furthermore, the method according to the invention and the device according to the invention also offer the possibility of producing a structured substrate, which can be used for further processing, for example chemical and/or physical

Treatment, in particular for coating by means of a chemical spray coating and/or suitable for improving the resulting anti-reflection properties and/or hydrophobic or superhydrophobic and/or hydrophilic or superhydrophilic properties of the

Increase and/or modify substrate.

According to a preferred embodiment of the present invention, the method disclosed herein is suitable for structuring a substrate surface in such a way that it anti-

Has glare properties. Structured ones are particularly suitable for this

Substrates with a dot structure, which - as defined herein - are formed from a first and a second or further interference pixel, the first and the second or each further interference pixel each independently having a periodic

Dot structure with dimensions in the micro- and sub-micrometer range, wherein the first interference pixel and the second or each further interference pixel are arranged superimposed on one another in such a way that the offset between the second or further

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Interference pixel and the first or the previous interference pixel in the range of LU102920 10% = < x < 50%, in particular in the range of 20% = < x < 50%, particularly preferably in

Range of 25% < x = 45% of the interference period.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

List of reference symbols LU102920 1 Laser radiation source 2 Beam splitter element 3 Beam path 4 Focusing element 5 Substrate 6 Further deflection element 7 Deflection element 8 Polarization element 9 Focusing mirror or galvo mirror 91 Polygon wheel

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Examples LU102920

The present invention is explained in more detail using the following figures and exemplary embodiments, without restricting the invention to these. In particular, in the individual

Features shown in the figures and described for the respective example are not limited to the respective individual example.

This shows

Fig. 1: a schematic perspective view of a device according to the invention.

Fig. 2: a schematic perspective view of a device according to the invention, which contains a deflection element (6) for parallelizing the partial beams.

Fig. 3: a schematic perspective view of a device according to the invention, which contains a deflection element (7) for widening the angle of the partial beams to the optical axis of the beam path (3).

Fig. 4A: a schematic perspective view of a device according to the invention, which has optical elements (6) with a planar, reflective surface that

Deflect partial beams onto the focusing element (4).

Fig. 4B: a schematic perspective view of a device according to the invention, which comprises a galvo mirror (9) as an optical element for beam shaping, which ensures a stationary positioning of the substrate to be structured during

Process of structuring allowed.

Fig. 5: a schematic perspective view of a device according to the invention, the device having a polarization element (8), which determines the phase profile of the

Partial beams shift to one another, containing a) the beam splitter element (2) in the beam path (3) close to the

Laser radiation source (1) is positioned. b) the beam splitter element (2) is positioned in the beam path (3) close to the deflection element (7).

Fig. 6: a schematic view of the surface or interior of the

Interference pixels resulting from the substrate with the width D, and the distribution of the individual interference pixels on the surface or inside the substrate, the interference pixels being shifted relative to one another with the pixel density Pd.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Fig. 7: a schematic perspective view of the structured substrate (5) with the LU102920 generated periodic point structures, consisting of inverse cones

Dimensions in the micro and submicron range, and symbolically the

Transmission of incident electromagnetic waves with wavelengths greater than the structural period of the generated structures, as well as the diffraction of incident electromagnetic waves with wavelengths in the range or smaller of the generated structures.

Fig. 8: a schematic perspective view of a device according to the invention, which has a galvo mirror (9) with a planar, reflecting element as an optical element

Surface that deflect the partial beams onto the focusing element (4), as well as a

Polygon wheel (91) contains.

Fig. 9: A graphical representation of the diffraction angle of incident light versus the

Wavelength of the incident light for structured substrates with three different structure widths.

Fig. 10: a schematic perspective view of the structured substrate (5) with the periodic point structures created, consisting of inverse cones

Dimensions in the micrometer range, which has a periodic wave structure in the

Submicrometer range is superimposed.

Fig. 1 visualizes the device according to the invention in a first exemplary embodiment, comprising a laser radiation source (1) for emitting a laser beam. In the

Beam path (3) of the laser beam is arranged behind the laser radiation source (1), there is a beam splitter element (2), which is movably arranged in the beam path (3). In the

The beam path (3) of the laser beam is arranged behind the beam splitter element (2), and there is a focusing element (4). In the beam path (3) of the laser beam behind the

Focusing element (4) is arranged, there is a holding device on which a substrate (5), preferably flat and/or transparent substrate, is mounted.

In this embodiment, the laser radiation source (1) emits a pulsed laser beam.

The laser radiation source here is a UV laser with a wavelength of 355 nm and a pulse duration of 12 ps. The radiation profile of the

In this embodiment, the laser radiation source corresponds to a top hat profile.

In this exemplary embodiment, the beam splitter element (2) corresponds to a diffractive one

Beam splitter element. Here, a diffractive beam splitter element is a beam splitter element that contains micro- or nanostructures. The beam splitter element (2) divides the

Laser beam in 4 partial beams.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

In this exemplary embodiment, the focusing element (4) corresponds to a refractive, LU102920 spherical lens, which directs the partial beams, which run essentially parallel to one another, onto the substrate (5), preferably a flat and/or transparent substrate, in such a way that they interfere there in an interference region. The interference angle corresponds to this

Design 27.2°, resulting in a structure period of 550 nm for the periodic

Dot structure results in the same polarization state.

According to this exemplary embodiment, the flat substrate is irradiated once, so that there is a processing time per structural unit, i.e. H. per interference pixel, of 12 ps.

The substrate (5), preferably a flat and/or transparent substrate, is a glass, particularly a quartz glass, which is mounted on a holding device so that it is in the xy plane, perpendicular to the beam path of the

Laser radiation source (1) emitted laser beam is movable.

In a further exemplary embodiment, Fig. 2 visualizes the device as described in Fig. 1, additionally comprising a deflection element (6), which is located in the beam path (3) of the laser after the beam splitter element (2) and the focusing element (4).

In this embodiment, the deflection element is a conventional, refractive, convex one

Lens. The partial beams hit the deflection element (6) in such a way that they

Passing through the deflection element run essentially parallel to each other. This allows the point at which the partial rays are on the surface or inside the

Substrate interfere, adjust.

In a further exemplary embodiment, FIG. 3 visualizes a device based on the structure shown in FIGS. 1 and 2. In addition, this structure includes another

Deflection element (7), which is in the beam path (3) of the laser between the

Beam splitter element (2) and the deflection element (6) is arranged.

In this embodiment, the further deflection element (7) is a conventional, refractive, concave lens. The partial beams hit the further deflection element in such a way that they

Angle to the optical axis of the beam path is expanded. This allows the

Interference angle with which the partial rays on the surface or inside the

Substrate, preferably flat and / or transparent substrate, interfere, change.

In this embodiment, all optical elements apart from the beam splitter element (2) are fixed along the optical axis of the beam path (3). The interference angle of the

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Partial beams on the substrate are adjusted by moving the beam splitter element (2) LU102920 along the optical axis of the beam path.

4A shows, in a further exemplary embodiment, a device as in FIG. 3, comprising the optical elements (6) with a planar, reflecting surface, which are set up in such a way that they deflect the partial beams onto the focusing element (4).

In this embodiment, the at least three partial beams are directed onto the substrate at a preferred angle by moving the optical elements (6). This means that a deflection element in the form of a lens (reference number (6) in Fig. 3) can be dispensed with.

In a further exemplary embodiment, Fig. 5 visualizes a device as in Fig. 3, additionally comprising one polarization element (8) per partial beam, which are arranged in the beam path (3) of the laser beam between the deflection element (6) and the focusing element (4).

The polarization element is arranged in such a way that it controls the polarization of the individual

Partial beams are changed relative to each other in such a way that a change in the interference pattern results.

This embodiment is shown in two different configurations. In Fig. 5 a), the beam splitter element (2) is positioned in the beam path (3) close to the laser radiation source (1). In Fig. 5 b), the beam splitter element (2) is close to the beam path (3).

Deflection element (7) positioned. In this way, the interference pattern of the interfering partial beams on the surface of the substrate (5) can be adjusted continuously without the other optical elements in the structure or the substrate having to be moved.

In addition, it would also be conceivable that the arrangement contains an additional optical element for beam shaping, which is in the beam path (3) of the laser beam

Laser radiation source (1) is arranged downstream. In this embodiment that corresponds

Radiation profile of the laser radiation source a GauB profile. The optical element for

Beam shaping converts this profile to a top hat profile.

Fig. 6 contains a schematic view of the surface or interior of the

Substrate resulting interference pixels with the width D, and the distribution of each

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Interference pixels on the surface or inside the substrate, the interference pixels LU102920 being shifted from one another with the pixel density Pd.

In this embodiment, the pixel density Pd is smaller than the width of an interference pixel, D.

As a result, by moving the substrate (5) using a pulsed laser beam, a flat, homogeneous periodic dot structure can be created on the surface or inside a

Substrate, preferably flat and / or transparent substrate, are generated.

Fig. 7 visualizes the structured substrate (5) generated by the method according to the invention with the periodic point structures generated, consisting of inverse cones

Dimensions in the micro and submicron range. It also becomes symbolic

Transmission of incident electromagnetic waves with wavelengths greater than that

Structural period of the generated structures, as well as the diffraction of incident electromagnetic waves with wavelengths in the range or smaller than those generated

Structures clarified.

8 shows, in a further exemplary embodiment, a device as in FIG. 4B, comprising the optical element (91) with a planar, reflecting surface, which is a polygonal wheel which is set up in such a way that it rotates about an axis shown . The incident partial beams are deflected in such a way that they hit a galvo mirror (9), which transmits the beams over a

Focusing element (4) directs onto the substrate. The rotation of the polygon wheel causes the point at which the rays are focused on the substrate during the

Exposure process is movable along a line. So the partial beams scan that

Substrate, which leads to increased process speed.

9 shows a graphic representation of the transmission or diffraction ability of a structured substrate depending on the structure width. The

Diffraction angle of light as a function of its wavelength is shown for structures with three different structural widths. If the wavelength of the incident light is greater than the structure width, the light is completely transmitted. At wavelengths in the range of the structural width or smaller, diffraction occurs. The diffraction angles can be seen from the graphic.

Fig. 10 visualizes the structured generated by the method according to the invention

Substrate (5) with the generated periodic point structures, consisting of inverse

Tenons, with dimensions in the micrometer range. This periodic point structure in

Overlaid on the micrometer range is a periodic wave structure in the submicrometer range,

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application which also uses the inventive method described herein in a LU102920

Production step can be generated.

FUBI-0002-P-LU March 31, 2022 Luxembourg patent application

Claims (11)

Patent claims LU102920 1. Laser interference structuring device for direct laser interference structuring of a substrate, comprising - a laser radiation source (1) for emitting a laser beam, - a beam splitter element (2) which is arranged in the beam path (3) of the laser beam, - a focusing element (4) which is set up in this way in that the partial beams pass through it in such a way that the partial beams can be interfered with on the surface or in the volume of a substrate (5) in an interference region, characterized in that the beam splitter (2) is freely movable along its optical axis in the beam path (3), the beam splitter (2) is designed to divide the incident laser beam, which is emitted by the laser radiation source (1), into at least 3 partial beams, with a first deflection element (2) downstream of the beam splitter element (2) in the beam path (3) of the laser radiation source (1). 7) is arranged in such a way that the at least three partial beams are expanded as they pass through the deflection element (7), the deflection element (7) being a concave lens. 2. Device according to claim 1, wherein in the beam path (3) of the laser radiation source (1) and the beam splitter element (2) a further deflection element (6) is arranged downstream, which is set up in such a way that it deflects the partial beams in such a way that they exit from the further deflection element (6) run essentially parallel to one another. 3. Device according to claim 1 or 2, wherein the beam splitter element (2) is a diffractive beam splitter element or a refractive beam splitter element. 4. Device according to claim 2, wherein the further deflection element (6) is a convex lens. FUBI-0004-P-LU March 31, 2022 Luxembourg patent application 5. Device according to one of the preceding claims, wherein the focusing element ~~ LU102920 (4) is a convex lens. 6. Device according to one of the preceding claims, wherein the device comprises at least one polarization element (8) which is arranged in the beam path between the deflection element and the focusing element. 7. Device according to one of the preceding claims, wherein the laser radiation source is a pulsed laser radiation source with pulse widths in the range from 10 nanoseconds to 10 femtoseconds. 8. Device according to one of the preceding claims, wherein the radiation profile of the laser beam emitted by the laser radiation source corresponds to a Gaussian profile or a top hat profile. 9. Device according to one of the preceding claims, wherein there is a further optical element in front of the beam splitter element, which can be used for beam shaping. 10. Device according to one of the preceding claims, wherein the device comprises a holding device on which the substrate is mounted and which is movable in the xy plane, perpendicular to the beam path (3) of the laser beam emitted by the laser radiation source (1). 11. Device according to one of the preceding claims, wherein the substrate comprises a transparent material. FUBI-0004-P-LU March 31, 2022 Luxembourg patent application