A filter attached to a support

Abstract

A filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm, and being attached to a support is disclosed. The filter comprises: a free-standing film of carbon nanostructures having a patterned mesh; and a coating of carbon nanostructures on the free-standing film of carbon nanostructures. Further is disclose a method for producing the filter, uses thereof, and an X-ray detector.

Description

[0001] A FILTER ATTACHED TO A SUPPORT

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to a filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm and being attached to a support . The present disclosure further relates to a method for producing a filter attached to a support . Further, the present disclosure relates to the use of the filter attached to a support . The present disclosure further relates to an X-ray detector .

[0004] BACKGROUND OF THE INVENTION

[0005] There are many applications where a filter transmitting radiation of a specific wavelength range while blocking e . g . particles or debris is needed . Photolithography used in semiconductor manufacturing may be mentioned as one example where filters are needed to prevent defects in the integrated circuit ( IC) . I f a photomask is contaminated with particles , the particles are imaged onto the resist causing defects . Further, X- ray detectors may in some applications be sensitive to photons outside the energy range of interest . Out-of- band radiation typically deteriorates the energy resolution, shifts the energy scale , or increases the background noise thus significantly compromising the detector performance . Thin filters , highly transparent to X- rays , are thus needed in front of such detectors to fully exploit their high sensitivity .

[0006] Previously used filters transmitting radiation of a specified wavelength range while blocking radiation outside the range , have often cons isted of a thin continuous 2D polymeric film, with a thickness ranging from few tens to hundreds of nanometres , typically coated with a thin metal mesh which is efficient in reflecting visible (VI S ) / infrared ( IR) radiation . Further, filters where the polymeric film is replaced with a carbon nanotube fi lm have been used . However, further options are needed .

[0007] SUMMARY OF THE INVENTION

[0008] A filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm and being attached to a support is disclosed . The filter comprises : a free-standing film of carbon nanostructures , wherein the free-standing film of carbon nanostructures is attached to the support , and wherein a patterned mesh is formed into at least one side of the free-standing film of carbon nanostructures ; and a coating of carbon nanostructures on the freestanding film of carbon nanostructures to at least partially cover the free-standing film of carbon nanostructures , wherein the coating is formed on the side of the free-standing film of carbon nanostructures where the patterned mesh is formed .

[0009] Further is disclosed a method for producing a filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm and being attached to a support . The method comprises :

[0010] - providing a free-standing film of carbon nanostructures attached to a support ;

[0011] - forming a patterned mesh into at least one side of the free-standing film of carbon nanostructures by irradiating with a laser beam;

[0012] - providing a coating of carbon nanostructures on the free-standing film of carbon nanostructures on the side of the free-standing film of carbon nanostructures where the patterned mesh is formed to at least partially cover the free-standing film of carbon nanostructures , to form the filter ; and - subj ecting the formed filter to a densifica- tion treatment by subj ecting the filter to a solvent to bond the coating of carbon nanostructures to the freestanding film of carbon nanostructures .

[0013] Further is disclosed the use of the filter attached to a support in an X-ray detector for space mission .

[0014] Further is disclosed the use of the filter attached to a support as an optical filter, a debris filter, a pellicle , a membrane filter, an electron blocking window, or any combination thereof .

[0015] Further is disclosed an X-ray detector comprising the filter attached to a support .

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings , which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention . In the drawings :

[0018] Fig . 1 illustrates the method for producing an filter attached to a support according to one embodiment ;

[0019] Fig . 2a illustrates a filter attached to a support according to one embodiment ;

[0020] Fig . 2b illustrates a cross-sectional view of the filter attached to the support of Fig . 2a ;

[0021] Fig . 3 shows pictures taken of the filters prepared in example 2 ;

[0022] Fig . 4 shows the results of example 3 .

[0023] DETAILED DESCRIPTION

[0024] A filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm and being attached to a support is disclosed . The filter comprises : a free-standing film of carbon nanostructures , wherein the free-standing film of carbon nanostructures is attached to the support , and wherein a patterned mesh is formed into at least one side of the free-standing film of carbon nanostructures ; a coating of carbon nanostructures on the freestanding film of carbon nanostructures to at least partially cover the free-standing film of carbon nanostructures , wherein the coating is formed on the side of the free-standing film of carbon nanostructures where the patterned mesh is formed .

[0025] In one embodiment, the filter is a free-standing filter attached to the support .

[0026] The inventors surprisingly found out that by using carbon nanostructures it is possible to form a filter that is able to transmit electromagnetic radiation with a wavelength range of up to 400 nm, while blocking electromagnetic radiation, with a wavelength range outside this range , from passing through the filter . In one embodiment , the fi lter is able to transmit electromagnetic radiation with a wavelength of 0 - 400 nm, or above 0 - 400 nm .

[0027] The ability of the filter to transmit and / or block electromagnetic radiation may be determined by a high spectral resolution transmission measurement using a synchrotron .

[0028] In one embodiment , the filter further comprises a blocking layer on the coating of carbon nanostructures . In one embodiment , the filter further comprises a metal blocking layer on the coating of carbon nanostructures . In one embodiment , the thickness of the blocking layer is 1 - 1000 nm, or 3 - 500 nm, or 5 - 250 nm, or 10 - 100 nm . The blocking layer may be formed of aluminium, zirconium, molybdenum, metal silicide , ruthenium, silicon boron, beryllium, niobium, or any a carbide , an oxide , or a nitrate thereof , or any combination or mixture thereof . The blocking layer may comprise or consist of aluminium, zirconium, molybdenum, metal silicide , ruthenium, silicon boron, beryllium, niobium, or any a carbide , an oxide , or a nitrate thereof , or any combination or mixture thereof . In one embodiment , a blocking layer, such as a metal blocking layer, is configured to block electromagnetic radiation with a wavelength above 400 nm, or above 450 nm, or above 500 nm . In one embodiment , a blocking layer, such as a metal blocking layer, is configured to block electromagnetic radiation in the visible wavelength range and microwaves from passing through or transmitting the filter . The blocking layer has the added utility of blocking radiation of undesired wavelength to pass through the filter . The inventors surprisingly found out that the formed f ilter may block low energy radiation, such as radiation in the visible wavelength range and microwaves , from passing through the filter . In one embodiment , the filter is blocking electromagnetic radiation with a wavelength range of above 400 nm . In one embodiment , the filter is configured to block electromagnetic radiation with a wavelength range of above 400 nm .

[0029] The filter thus is configured to transmit electromagnetic radiation with a wavelength range of up to 400 nm . The filter is thus able to transmit "high energy radiation" such as X-radiation and extreme ultraviolet radiation . In one embodiment , the filter is configured to transmit ioni zing radiation . In one embodiment , the filter is configured to transmit X-radiation and extreme ultraviolet radiation . In one embodiment , the filter is configured to transmit X-radiation or extreme ultraviolet radiation . Further is disclosed a method for producing a filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm and being attached to a support . The method comprises :

[0030] - providing a free-standing film of carbon nanostructures attached to a support ;

[0031] - forming a patterned mesh into at least one side of the free-standing film of carbon nanostructures by irradiating with a laser beam;

[0032] - providing a coating of carbon nanostructures on the free-standing film of carbon nanostructures on the side of the free-standing film of carbon nanostructures where the patterned mesh is formed to at least partially cover the free-standing film of carbon nanostructures , to form the filter ; and

[0033] - subj ecting the formed filter to a densifica- tion treatment by subj ecting the filter to a solvent to bond the coating of carbon nanostructures to the freestanding film of carbon nanostructures .

[0034] Further is disclosed, the use of the filter attached to a support in an X-ray detector for space mission .

[0035] Further is disclosed the use of the filter attached to a support as an optical filter, a debris filter, a pellicle , a membrane filter, an electron blocking window, or any combination thereof .

[0036] An optical filter is a filter or device that that selectively transmits light or radiation of different wavelengths . An x-ray optical filter thus transmits x-ray radiation but may rej ect radiation of some different wavelength ( s ) . Similarly, the EUV (extreme ultraviolet ) optical filter may transmit EUV radiation but may rej ect radiation of some different wavelength ( s ) . Another filter example is a debris filter, or a particle filter as it may also be called . An example of a debris filer is the EUV debris filter, that may transmit EUV radiation but may block debris and parti cles from passing through .

[0037] An electron blocking window is a device that block electrons from transmitting through . An example of an electron blocking window is the electron blocking X-radiation window . An electron blocking X-radiation window is a device that transmits x-ray radiation and blocks electrons from transmitting through .

[0038] In one embodiment , the optical filter is an X- ray optical filter, an extreme ultraviolet (EUV) optical filter, or a combination of these . In one embodiment , the optical filter is an X-ray optical filter and an extreme ultraviolet (EUV) optical filter . In one embodiment , the optical filter is an X-ray optical filter or an extreme ultraviolet (EUV) optical filter .

[0039] In one embodiment , the filter is used as an EUV debris filter, an EUV optical f ilter, or as a combination of these . In one embodiment , the filter is used as an EUV debris filter and an EUV optical fi lter . In one embodiment , the filter is used as an EUV debri s fi lter or an EUV optical filter .

[0040] In one embodiment , the filter is used in an electromagnetic shield, as a detector shield, in a wearable flexible electronic, in a wearable and implantable sensor, in a biosensor, in a gas sensor, in an electrochemical sensor, or in a strain sensor .

[0041] In one embodiment , the pellicle is an extreme ultraviolet lithography pellicle .

[0042] Further is disclosed an X-ray detector comprising the filter attached to a support .

[0043] The expression that the coating of carbon nanostructures is "on" the free-standing film of carbon nanostructures should be understood in this specification, unless otherwise stated, as meaning that the coating of carbon nanostructures is provided or formed to lie on or upon the free-standing film of carbon nanostructures . The free-standing film of carbon nanostructures may serve as a carrier or support structure for the coating of carbon nanostructures . In one embodiment , the coating of carbon nanostructures is provided directly on the free-standing film of carbon nanostructures without further layers , coatings , or films being situated there between .

[0044] The coating of carbon nanostructures is formed such as to at least partially cover the free-standing fi lm of carbon nanostructures . There may thus be parts or areas of the free-standing film of carbon nanostructures or of the patterned mesh that are not covered by the coating of carbon nanostructures . By only partial coverage of the free-standing film of carbon nanostructures , one may provide a filter having areas with higher optical transmission or where particles , that are otherwise wanted to be blocked, are let through the filter .

[0045] In one embodiment , the coating of carbon nanostructures is formed to cover essentially the whole area of the free-standing film of carbon nanostructures on the side where the patterned mesh is formed .

[0046] In one embodiment , the filter comprises a coating of carbon nanostructures on both sides of the freestanding film of carbon nanostructure . In one embodiment , the method compri ses forming a coating of carbon nanostructures on both sides of the free-standing film of carbon nanostructures .

[0047] The expression "filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm", or the "filter" as is used for smoother reference throughout this specification, should be understood in this specification, unless otherwise stated, as referring to a structure having its lateral dimensions substantial ly larger than its thickness . In that sense , a filter may be considered as being a planar "thin" film or structure .

[0048] The term "mesh" may in this specification refer to an interlaced structure . The form of the mesh may be selected based on the form of the support . The mesh may be considered as a network forming a defined symmetry or form . The mesh provided into the free-standing fi lm of carbon nanostructures may have any form suitable for an application where the filter is to be used . The mesh may have a form of a structured grid or an unstructured grid . The mesh may have a symmetrical form or a non- symmetrical form . The mesh may have e . g . a triangular symmetry, a rectangular symmetry, or a hexagonal symmetry . In one embodiment, the mesh has a hexagonal symmetry . A hexagonal-patterned mesh has the added utility of exhibiting a high rigidity due to its constructions . A hexagonal-patterned mesh may withstand stretching and bending without getting damaged, for example when being rolled into a specific radius .

[0049] The filter as disclosed in the current specification comprises a free-standing film of carbon nanostructures that i s attached to a support and where into a patterned mesh is formed into at least one side of the free-standing film of carbon nanostructures . In one embodiment , a patterned mesh is formed on one s ide of the free-standing film of carbon nanostructures .

[0050] Previously such a mesh structure has been formed by a separate metal mesh, such as an aluminium mesh, provided on a polymer film . The inventors surprisingly found out that the function of such a rather heavy metal mesh may be replaced by patterning a mesh into the free-standing film of carbon nanotubes , on which is then provided a separate coating of carbon nanostructures .

[0051] Providing a patterned mesh into the free-standing film of carbon nanostructures has the added utility of exhibiting improved X-radiation and extreme ultraviolet radiation transmittance compared to the previously used metal mesh . In addition, such a patterned mesh has the added utility of tolerating mechanical vibrations to a larger extent than a metal mesh, which is sensitive to strokes and vibrations .

[0052] The inventors thus surprisingly found out that it is possible to form a filter having the ability of transmitting ioni zing radiation such as X-radiation and extreme ultraviolet radiation but that hinders other types of radiation, such as radiation of visible wavelength range , infrared radiation, microwave radiation, and radio wave radiation, from passing through the filter . In one embodiment , the filter is configured to hinder radiation of the visible wavelength range , infrared radiation, microwave radiation, radio wave radiation, or any combination of these , from passing through the filter .

[0053] Total thickness of the filter may be 10 - 9000 nm, or 15 - 5000 nm, or 20 - 2500 nm, or 25 - 1000 nm, or 50 - 500 nm, or 75 - 300 nm, or 90 - 200 nm . In one embodiment , the total thickness of the filter may be 10 - 100 nm, 50 - 500 nm, or 250 - 2500 nm . The thickness of the filter, or the parts thereof , may be measured with a contact profilometer, such as atomic force microscopy (AFM) , an optical profilometer, or an ellipsometry, cross-sectional electron microscopy . The filter has the added utility of being a thin filter compared to the previously used filters where a separate metal mesh is used .

[0054] The filter may exhibit a percent transmittance ( %T ) value of 1 - 99 % , or 5 - 95 % , or 10 - 90 % , or 20 - 80 % , or 30 - 70 % , or 40 - 60 % , when measured at a wavelength range of 10 - 31 nm . The filter may exhibit a percent transmittance value of 20 - 99 % , or 30 - 60 % , or 30 - 50 % , when measured at a wavelength range of 13 . 5 nm . The percent transmittance value may be measured by a spectroscopic method . Providing the fi lter with a metal layer may affect the transmittance of the filter but not to a too adverse extent . The term "percent transmission value" may also be used instead of "percent transmittance value".

[0055] The "filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm", or the "filter", is attached to a support. The support may be any type of support suitable to be attached with the free-standing film of carbon nanostructures and thus with the free-standing filter. The support may be formed of a polymer, a metal, silicon, glass, a ceramic material, a fibrous material, such as paper or cardboard, or any combination thereof. The form of the support may vary. The support may have the form of a frame. In one embodiment, the support has the form of a frame, and the filter is attached to the frame. The frame may support the filter at the outer edges thereof such that an unsupported standalone region of the filter is formed. The support positions may be located anywhere in the structure as long as they provide sufficient support for the filter. For example, they may be on the sides of the filter, or in areas near corners, or next to each other along the sides. Any wider area that includes a plurality of support points is also meant to be covered by this aspect, for example if the frame has an uninterrupted circular shape wherein the free-standing region lies within the circle. The frame may also have any other prolonged uninterrupted shape. In one embodiment, the frame is shaped as a circle, a square, a triangle, a rectangle, an oval, or a polygon.

[0056] Carbon nanostructures are used to form the free-standing film and the coating, respectively. The expression "nanostructures" should be understood in this specification, unless otherwise stated, as structures with one or more characteristic dimensions in nanometer scale, i.e. at most about 100 nanometers. The dimensions of the conductive nanostructures, in two perpendicular directions, may be in significantly different magnitudes of order. For example, a nanostructure may have a length which is ten, hundred, or even hundred thousand, times higher than its thickness or width . In a film of carbon nanostructures , a great number of said carbon nanostructures are interconnected with each other to form a network of interconnected molecules . As considered at a macroscopic scale , such a network forms a solid, monolithic material in which the individual molecular structures are disoriented or non-oriented, i . e . are oriented substantially randomly, or oriented . Various types of carbon nanostructure networks can be produced in the form of thin transparent layers .

[0057] In one embodiment , the carbon nanostructures comprise carbon nanotubes (CNT) , carbon nanobuds (CNB) , carbon nanoribbons , or any combination or mixture thereof . In one embodiment , the carbon nanostructures comprise carbon nanotubes , carbon nanobuds , or a combination or mixture of these . The carbon nanobuds , or the carbon nanobud molecules as they also may be called, have fullerene or fullerene-like molecules covalently bonded to the side of a tubular carbon molecule . Carbon nanotubes and carbon nanobuds as such have the added utility of being highly transparent in the X-ray and visible light wavelengths . In addition they have robust mechanical properties and high chemical inertness .

[0058] Various procedures exist in the art that may be used for forming the free-standing film or coating of carbon nanostructures , respectively . Different manner may be used to synthesi ze the carbon nanostructures and / or to deposit the same to form a fi lm . In the case of e . g . carbon nanotubes or carbon nanobud molecules , deposition may be carried out , for example , by using the commonly known methods of filtration from gas phase or from liquid, deposition in a force field, or deposition from a solution using spray coating or spin drying . The carbon nanobud molecules can be synthesi zed, for example , using the method disclosed in WO 2007 / 057501 , and deposited on a substrate , for example , directly from the aerosol flow, e.g. by assistance of e.g. electrophoresis or thermophoresis, or by a method described in Nasibulin et al: "Multifunctional Free-Standing Single-Walled 20 Carbon Nanotube Films", ACS NANO, vol. 5, no. 4, 3214- 3221, 2011. Functionalization of carbon nanostructures may be considered as the generation of functional groups on the surfaces of the carbon nanostructures. Functionalization of the carbon nanostructures has the added utility of making them more reactive, increasing their solubility, or allowing various chemical modifications, such as ion adsorption, metal deposition, or grafting reactions .

[0059] A free-standing film of carbon nanostructures may be formed by synthesizing carbon nanostructures e.g. in a gas phase from where they are collected or deposited. The film of carbon nanostructures may be formed by collecting or depositing the synthesized carbon nanostructures firstly in one direction in reaction chamber, the rotating the same e.g. 90 degrees and to continue collecting or depositing further carbon nanostructures thereon. Alternatively, the carbon nanostructures may be randomly collected or deposited to form a film of carbon nanostructures.

[0060] In one embodiment, the free-standing film of carbon nanostructures is a free-standing film of horizontally aligned carbon nanotubes. Aligning the carbon nanostructures horizontally has the added utility of increasing the strength of the film. In one embodiment, the free-standing film of carbon nanostructures is a free-standing film of randomly deposited carbon nanostructures .

[0061] In one embodiment, the thickness of the freestanding film of carbon nanostructures is 8 - 7000 nm, or 20 - 5000 nm, or 50 - 2500 nm, or 100 - 1000 nm, or 200 - 600 nm. Forming a free-standing film of carbon nanostructures has the added utility of one being able to form a thin film. However, the free-standing film of carbon nanostructures may not be too thin as this would affect its ability to support itself when attached to the support .

[0062] Having provided the free-standing film of carbon nanostructures , a patterned mesh is formed into at least one side of the free-standing film of carbon nanostructures . A laser beam may be used to take out areas such that a mesh with a predetermined pattern is formed . The laser beam is thus used to irradiate the surface of the free-standing film of carbon nanostructures . The irradiation may be carried out by laser ablation . Laser ablation, or photoablation as it may also be called, is the process of removing material from a solid surface by irradiating it with a laser beam .

[0063] Using a laser irradiation to form the patterned mesh has the added utility that the material to be removed is "ablated" away rather than "cut" away that would result in f lakes being formed and possibly stuck within the formed mesh . In one embodiment , the patterned mesh is a laser-formed patterned mesh . Laser-forming or laser-patterning has the further added utility of enabling to form a patterned mesh into the free-standing film, i . e . on a film that is not supported all over its area but has a free-standing part . Further, using irradiation with a laser beam enables to process a freestanding film of carbon nanostructures having even a very low thickness .

[0064] Forming the patterned mesh directly in the free-standing film of carbon nanostructures has the added utility of one being able to reduce the total thickness of the filter when the previously used metal mesh can be excluded .

[0065] A coating of carbon nanostructures is then provided on the free-standing film of carbon nanostructures on the side of the free-standing film of carbon nanostructures where the patterned mesh is formed to at least partially cover the free-standing film of carbon nanostructures , to form the filter . The coating of carbon nanostructures may be formed as above explained for forming a free-standing film of carbon nanostructures . Thus , a separate coating of carbon nanostructures is formed and placed on the free-standing film of carbon nanostructures .

[0066] In one embodiment , the coating of carbon nanostructures is a coating of hori zontally aligned carbon nanotubes . In one embodiment , the coating of carbon nanostructures is a coating of randomly oriented carbon nanostructures . The coating of carbon nanostructures may be formed of layers of carbon nanostructures , where one of the layers comprises carbon nanostructures aligned in a first direction, followed by a layer of carbon nanostructures aligned in a second direction, being different from the f irst direction etc . The directions of the alignments may vary with an angle of 45° - 90° .

[0067] The thickness of the coating of carbon nanostructures may be thinner than the thickness of the free-standing film of carbon nanostructures . In one embodiment , the thickness of the coating of carbon nanostructures is 1 - 1000 nm, or 5 - 500 nm, or 10 - 250 nm, or 20 - 150 nm, or 25 - 75 nm . In one embodiment , the thickness of the coating of carbon nanostructures is 1 - 1000 nm, or 5 - 500 nm, or 10 - 250 nm, or 20 - 150 nm, or 25 - 75 nm . When providing a coating of carbon nanostructures with such a thickness one is able to maintain an X-ray or EUV transmission through the filter while blocking other wavelengths from passing through the filter .

[0068] Using carbon nanostructure both in forming the free-standing film that is patterned and in forming the coating, has the added utility of one being able to produce a free-standing filter of varying si ze , and especially a large si zed filter where needed . In some embodiments , the si ze of the filter may exceed 1000 cm2yet having a relatively very thin film . In one embodiment , the filter has the si ze of 0 . 1 - 1000 cm2, or 1 - 500 cm2, or 5 - 350 cm2, or 10 - 200 cm2, or 50 - 150 cm2.

[0069] Having formed the coating of carbon nanostructures on the free-standing film of carbon nanostructures provided with a patterned mesh, one may proceed with densifying the formed filter . The densif ication may be conducted by using a solvent . The solvent may be used as vapor or a liquid . When a liquid solvent is used, it may be sprayed on the formed filter, or the formed filter may be dipped into the liquid solvent .

[0070] In one embodiment , the solvent is a vapori zed solvent . In one embodiment , the densif ication may be conducted using a solvent , such as isopropanol , in vapor phase . The formed filter may be placed in a chamber where to a solvent vapor is introduced . This solvent vapor may then condense onto the filter, forming a liquid thin solvent film . The drying effect and surface tension of the solvent film may then pull the structure of the filter together to form a denser and mechanically stronger filter . The temperature of the used solvent vapor may be either cold, warm, or hot .

[0071] Densif ication of the filter has the added utility of coupling or bonding the free-standing film of carbon nanostructures and the coating of carbon nanostructures such that they are adhered to each other . The adhes ion i s remained even in harsh conditions . The densif ication may compress together the coating of carbon nanostructures and the free-standing film of carbon nanostructures , forming a monolithic structure , where the carbon nanostructures may strongly adhere to each other through van der Waals forces .

[0072] In one embodiment , the method comprises providing a blocking layer on the coating of carbon nanostructures . In one embodiment , the method comprises providing a metal blocking layer on the coating of carbon nanostructures . The method may comprise providing a blocking layer, such as a metal blocking layer , on the coating of carbon nanostructures before or after the densif ication treatment . The blocking layer, such as a metal blocking layer, may be formed before or after the densif ication . In one embodiment , the method comprises providing a metal blocking layer on the coating of carbon nanostructures for increasing the electrical conductivity of the f ilter . In one embodiment , the filter comprises a metal blocking layer on the coating of carbon nanostructures for increasing the electrical conductivity of the filter . In one embodiment , the blocking layer is a metal blocking layer conf igured to increase the electrical conductivity of the filter . Doping or layering with a metal has the added utility of providing the filter with increased electrical conductivity which may be of use in e . g . an electromagnetic interference (EMI ) shield or a radio frequency (RF) shield . The metal layer may be formed by electrodeposition, physical vapor deposition ( PVD) , chemical vapor deposition (CVD) or atomic layer deposition (ALD) technology .

[0073] The filter attached to a support has the added utility of being able to transmit ioni zing radiation, such as X-radiation and EUV radiation, while simultaneously blocking undesired radiation from passing the filter .

[0074] The filter as disclosed in the current specification may be taken as a monolithic filter since it may be formed of merely carbon nanostructures . Thus , in one embodiment , the filter is a monolithic fi lter . The carbon element has a certain atomic and electronic structure that allow radiation of the defined wavelength range , such as X-radiation and extreme ultraviolet radiation, to pass through it without interacting with the carbon to the same extent as with e . g . a metal .

[0075] The filter attached to a support has the added utility of exhibiting excellent mechanical properties in what comes to withstand vibration and acceleration needed in e . g . aerospace applications .

[0076] Under vibration conditions , such as during a space launch and mission, the interface between the freestanding film of carbon nanostructures and the coating of carbon nanostructures may transmit vibrations therebetween .

[0077] The filter attached to the support has the added utility of exhibiting a strong adhesion between the free-standing film of carbon nanostructures and the coating of carbon nanostructures as both are formed of carbon nanostructures .

[0078] The filter attached to the support has the added utility of being formed of merely carbon nanostructures that may provide the filter with thermal and mechanical stability . Further, the filter has the added utility of being easy to recycle .

[0079] The filter attached to the support has the further added utility of being able to provide physical protection, electromagnetic shielding, field uniformity, gas containment , ioni zation collection or a combination of these .

[0080] EXAMPLES

[0081] Reference will now be made in detail to the described embodiments , an example of which is illustrated in the accompanying drawing .

[0082] The description below discloses some embodiments in such a detail that a person skilled in the art is able to uti li ze the method based on the di sclosure . Not all steps of the embodiments are discussed in detail , as some of the steps may be obvious for the person skilled in the art based on this specification .

[0083] For reasons of simplicity, item numbers will be maintained in the following exemplary embodiments in the case of repeating components .

[0084] Fig . 1 illustrates one embodiment of the method for producing a filter 1 transmitting electromagnetic radiation with a wavelength range of up to 400 nm, and being attached to a support 2 . The formed filter 1 is schematically illustrated in Fig . 2a and its cross-sectional view is illustrated in Fig . 2b . The method according to the embodiment of Fig . 1 comprises to firstly provide a free-standing film of carbon nanostructures 3 attached to a support 2 . Thereafter a patterned mesh 5 is formed into one side 3a of the free-standing film of carbon nanostructures by irradiating with a laser beam . Having formed the mesh of a des ired pattern, a coating of carbon nanostructures 4 is provided on the freestanding film of carbon nanostructures 3 on the side 3a of the free-standing film of carbon nanostructures where the patterned mesh is formed to at least partially cover the free-standing film of carbon nanostructures . Thus , the filter 1 is formed . Having formed the filter, it is subj ected to a densif ication treatment . The filter 1 is subj ected to a solvent in order to bond the coating of carbon nanostructures to the free- standing film of carbon nanostructures .

[0085] Example 1 - Producing a filter attached to a support

[0086] In thi s example a filter was produced and its properties were tested . The filters were formed following the above presented in relation to Fig . 1 . The following materials were used :

[0087] * *A circular frame , 21 mm inner diameter, 37 mm outer diameter

[0088] Firstly, carbon nanotubes were synthesi zed in an aerosol laminar flow ( floating catalyst ) reactor us ing carbon monoxide and ferrocene as a carbon source and a catalyst precursor, respectively . The formed carbon nanotubes were deposited from the gas phase onto a porous collection filter at a total gas flow rate of 60 1 / min (gas velocity of max 0 . 13 m / s ) to form a f ilm of carbon nanotubes on the porous collection filter . The temperature of the gas was about 60 ° C . The thickness of the formed film of carbon nanotubes was 150 nm .

[0089] The formed film of carbon nanotubes was then transferred from the porous collection filter to a rectangular plastic frame that was larger than the final circular frame . Then the same was transferred to the final circular-shaped frame to form a free-standing film of carbon nanotubes attached to the frame . The frame thus had a circular form with an opening in the middle .

[0090] Thereafter a hexagonal-patterned mesh was formed into one side of the free-standing film of carbon nanotubes by irradiating with a laser beam ( 1 W power at 200 kHz at UV ( 355 nm) wavelength) .

[0091] Having formed the hexagonal-patterned mesh, a coating of carbon nanostructures was formed as above described for the free-standing film of carbon nanotubes and provided on the free-standing film of carbon nanostructures on the side of the free-standing film of carbon nanostructures where the hexagonal-patterned mesh was formed . The coating of carbon nanostructures covered the free-standing film of carbon nanostructures . The thickness of the coating of carbon nanostructures was 85 nm .

[0092] The above formed filter was the subj ected to densif ication by placing the filter into chamber into which an isopropanol vapor was introduced at a temperature of 82 °C . The densif ication treatment resulted in the coating of carbon nanotubes being bonded to the free-standing film of carbon nanotubes . Further, an aluminium metal blocking layer having a thickness of 50 nm was provided on the coating of carbon nanostructures .

[0093] The formed filter was subj ected to high spectral resolution transmission measurements using a synchrotron . It was noticed that the formed filter was able to transmit electromagnetic radiation having a wavelength range of up to 400 nm but to block low energy radiation .

[0094] Example 2 - Producing filters attached to a support

[0095] In this example three different filters were formed as above described in example 1 but with varying the thicknesses of the free-standing film of carbon nanostructures and of the coating of carbon nanostructures . Pictures of the prepared filters are shown in Fig . 3 , where the total thicknesses of the filters from left to right are 216 nm, 447 nm, and 1466 nm . The percent transmittance value ( %T) of the formed filters were measured by a spectroscopic method and the following values were measured : 0 . 2 , 15 , and 40 , respectively .

[0096] Example 3 - Producing a filter attached to a support

[0097] Three different filters were produced as above described for example 1 , with the exception that the thickness of the aluminium blocking layer was varied . Samples with aluminium blocking layers of 20 nm, 30 nm, and 50 nm, respectively, were formed . The percent transmittance values thereof may be measured by a spectroscopic method . The Fig . 4 , one may see how the thickness of the aluminium blocking layer affected the percent transmittance values at certain wavelengths . It is obvious to a person skil led in the art that with the advancement of technology, the basic idea may be implemented in various ways . The embodiments are thus not limited to the examples described above ; instead they may vary within the scope of the claims .

[0098] The embodiments described hereinbefore may be used in any combination with each other . Several of the embodiments may be combined together to form a further embodiment . A filter, a method, use , or X-ray detector, as disclosed herein, may comprise at least one of the embodiments described hereinbefore . It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments . The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages . It will further be understood that reference to "an" item refers to one or more of those items . The term "comprising" is used in this specification to mean including the feature ( s ) or act ( s ) followed thereafter, without excluding the presence of one or more additional features or acts .

Claims

CLAIMS1. A filter (1) transmitting electromagnetic radiation with a wavelength range of up to 400 nm, and being attached to a support (2) , wherein the filter comprises : a free-standing film of carbon nanostructures (3) , wherein the free-standing film of carbon nanostructures is attached to the support (2) , and wherein a patterned mesh (5) is formed into at least one side (3a, 3b) of the free-standing film of carbon nanostructures; and a coating of carbon nanostructures (4) on the free-standing film of carbon nanostructures (3) to at least partially cover the free-standing film of carbon nanostructures, wherein the coating is formed on the side (3a, 3b) of the free-standing film of carbon nanostructures where the patterned mesh (5) is formed.

2. The filter of claim 1, wherein the filter further comprises a blocking layer on the coating of carbon nanostructures.

3. The filter of claim 2, wherein the thickness of the blocking layer is 1 - 1000 nm, or 3 - 500 nm, or 5 - 250 nm, or 10 - 100 nm.

4. The filter of any one of the preceding claims, wherein the filter (1) has a total thickness of 10 - 9000 nm, or 15 - 5000 nm, or 20 - 2500 nm, or 25 - 1000 nm, or 50 - 500 nm, or 75 - 300 nm, or 90 - 200 nm.

5. The filter of any one of the preceding claims, wherein the filter (1) exhibits a percent transmittance value of 1 - 99 %, or 5 - 95 % , or 10 - 90 % , or 20 - 80 %, or 30 - 70 %, or 40 - 60 %, when measured at a wavelength range of 10 - 31 nm.

6. The filter of any one of the preceding claims, wherein the thickness of the free-standing film of carbon nanostructures (3) is 8 - 7000 nm, or 20 -5000 nm, or 50 2500 nm, or 100 1000 nm, or 200 600 nm.

7. The filter of any one of the preceding claims, wherein the thickness of the coating of carbon nanostructures (4) is 1 - 1000 nm, or 5 - 500 nm, or 10 - 250 nm, or 20 - 150 nm, or 25 - 75 nm.

8. The filter of any one of the preceding claims, wherein the free-standing film of carbon nanostructures (3) is a free-standing film of horizontally aligned carbon nanotubes.

9. The filter of any one of the preceding claims, wherein the coating of carbon nanostructures (4) is a coating of horizontally aligned carbon nanotubes.

10. The filter of any one of the preceding claims, wherein the patterned mesh (5) is a laser-formed patterned mesh.

11. The filter of any one of the preceding claims, wherein filter (1) has the size of 0.1 - 1000 cm2, or 1 - 500 cm2, or 5 - 350 cm2, or 10 - 200 cm2, or 50 - 150 cm2.

12. The filter of claim 2, wherein the blocking layer is a metal blocking layer configured to increase the electrical conductivity of the filter.

13. A method for producing a filter transmitting electromagnetic radiation with a wavelength range of up to 400 nm, and being attached to a support (2) , wherein the method comprises:- providing a free-standing film of carbon nanostructures (3) attached to a support (2) ;- forming a patterned mesh (5) into at least one side (3a, 3b) of the free-standing film of carbon nanostructures by irradiating with a laser beam;- providing a coating of carbon nanostructures (4) on the free-standing film of carbon nanostructures (3) on the side (3a, 3b) of the free-standing film of carbon nanostructures where the patterned mesh (5) isformed to at least partially cover the free-standing film of carbon nanostructures, to form the filter, and- subjecting the formed filter to a densifica- tion treatment by subjecting the filter to a solvent to bond the coating of carbon nanostructures to the freestanding film of carbon nanostructures.

14. The method of claim 13, wherein the irradiating with a laser beam is carried out by laser ablation.

15. The method of any one of claims 13 - 14, wherein the method comprises providing a blocking layer on the coating of carbon nanostructures before or after the densif ication treatment.

16. The method of any one of the claims 13 - 15, wherein the solvent is a vaporized solvent.

17. The method of any one of claims 13 - 16, wherein the method comprises providing a metal blocking layer on the coating of carbon nanostructures for increasing the electrical conductivity of the filter.

18. Use of the filter attached to a support (2) of any one of claims 1 - 12 in in an X-ray detector for space mission.

19. Use of the filter attached to a support (2) of any one of claims 1 - 12 as an optical filter, a debris filter, a pellicle, a membrane filter, an electron blocking window, or any combination thereof.

20. An X-ray detector comprising the filter attached to a support (2) of any one of claims 1 - 12.

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