FI123883B - Target material, coating and coated object - Google Patents

Abstract

A coating material is used for coating a substrate by means of laser ablation. The coating material contains graphitic carbon nitride and a dopant in order to alter the properties of the coating produced as compared to a coating of pure carbon nitride.

Description

Target material, coating and coated object - Mälmaterial, beläggning, och ett belagt föremäl

ENGINEERING

The invention relates generally to coatings and to target materials for making coatings which provide the desired surface properties of the article. In particular, the invention relates to the use of doped carbon nitride as a coating material for laser ablation and to a coating made from such material by laser ablation and to an article coated therewith.

BACKGROUND OF THE INVENTION

10 The appearance and technical properties of objects are usually influenced by coating. In technical applications, interesting properties of the coating are e.g. thickness, transparency or translucency, color, fluorescence, hardness, homogeneity, surface roughness, compatibility with various substrates, adhesion to substrates, anti-diffusion properties, chemical and tri-biological properties, biocompatibility, electrical and thermal properties . Typical coating processes include, for example, vacuum evaporation, anodization, sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), Molecular beam epitaxy (MBE), and laser blocking. In the latter, high power ultrasound ultra-short laser pulses hit the target and ablate therefrom a plasma-shaped coating material which hits the substrate to be coated to form the desired coating.

One known coating material is the graphite carbon nitride C3N4 + xHy, which at the time of writing this text is provided, for example, by Carbodeon Ltd Oy, Helsinki, ™ 25 Finland under the registered trademark Nicanite®. It has a number of advantageous properties such as hardness, excellent wear resistance in tribological applications, chemical inertness, good yield, ability to fine tune the coating and coating process, non-toxic raw materials and environmentally friendly production process.

However, graphite carbon nitride does not solve all the coating problems, for example, it cannot be used as a fluorescent coating to produce white light with LEDs (Light Emitting Diode), since its ultraviolet excited fluorescence is in the wavelength range 390-450 nm, ie 2 at the slowest, blue end. Also, in all coating applications, carbon nitride does not achieve the desired uniformity or other desired surface micro, nano and / or crystal structure. Carbon nitride coatings on optical components do not easily achieve the desired transparency or wavelength-5 lectivity. Figure 1 shows the measured transmittance of a 800 nanometer carbon nitride coating over a wavelength range extending a few hundred nanometers on each side of visible light.

There are a wide range of applications that require both good abrasion resistance and low friction at the same time. Further, the coating is often expected at the same time, for example, to be easy to clean or slightly soiled. In some applications, the coating should still be sufficiently transparent at the same time. Typical applications include electronic product displays and enclosure solutions.

Typical low-fouling, low-friction coatings include, for example, polytetrafluoroethylene-based coatings in a variety of industrial processors and household products. In addition to limited wear resistance, the use and life span of products are limited by their relatively poor heat resistance. When exposed to higher temperatures (> 250 ° C), most polytetrafluoroethylene products are thermally decomposed to form hazardous gaseous fluorine containing compounds.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide a coating material, a coating and a coated article which achieves the desired technical properties. In particular, it is an object of the invention to provide a coating material, a coating and a coated article having desirable properties in the visible light region, such as

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such as fluorescence, transparency, reflectivity and / or wavelength selectivity. It is a further object of the invention to provide a coating material, a coating and a coated article having the desired hardness and the desired hydrophilicity or | -fobisuus. It is a further object of the invention to provide a coating material, a coating and a coated article having the desired surface uniformity or other desired g micro, nano and / or crystal structure. It is a further object of the invention to provide a coating material, a coating, and a coated article, wherein the coating has the desired anti-diffusion properties.

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The objects of the invention are achieved by using doped carbon nitride as the coating material. A significant advantage in achieving the objects of the invention is that the laser coating is used as the coating method and that the target from which the laser is produced has a sufficiently high density and a sufficiently small particle size and that its alloying agent contains nano diamonds, boron nitride and / or boron carbide.

The target material according to the invention is characterized by what is said in the characterizing part of the independent claim on the target material.

The coating according to the invention is characterized by what is said in the characterizing part of the independent claim on a pin-10 knife.

The coated article according to the invention is characterized by what is said in the characterizing part of the independent claim on the coated article.

Graphite carbon nitride, exemplified by nicanite (Nicanite®), is, by its name, a graphite or crystalline structure characterized by sp2-type bonds that allow carbon and nitrogen atoms to form flat, 2-dimensional structures. The alloying of graphite carbon nitride with, for example, nanotubes, boron compounds, hydrogen, fluoropolymer (s) and / or one or more rare earth (or alkali or alkaline) metals changes its properties in a manner that can be very surprising and useful.

For example, the carbon nitride coating doped with nano-diamonds has been found to be extremely hard and has exhibited a clear red shift in the visible light fluorescence compared to pure carbon nitride. The doping with boron compounds can produce a coating which is very hard and / or almost completely transparent in the range of visible light. Hydrogen alloying relaxes the double bonds between carbon and nitrogen atoms, which changes the two-dimensional crystal structure in a three-dimensional direction and improves coating uniformity and surface quality, x Alloying with rare-earth metals, alkali metals, or alkali metals.

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earth metals can produce wavelength selectivity and / or fluorescence similar to that found in the coating.

O) The doping can be done using a laser blotting target where the desired dopant is present. Another possibility is to introduce the desired dopant into the laser ablation chamber in gaseous or particulate form. A third possibility is to use two or more targets in laser bleaching, 4 of which are ablated with carbon nitride and dopant simultaneously or alternately. These possible methods of preparation are not mutually exclusive, but it is very possible to use, for example, a pre-doped target and a gaseous dopant or two targets, one being carbon-5 alloyed and the other being carbon dioxide or another doped.

The coated object may be, for example, a cutting tool, an optical component, an LED component, or a fluorescent housing for an LED component. In the case of a cutting tool, the hardness, stability and tribological properties of the coating are generally preferred, but the fluorescence properties can be an unpredictable advantage, for example when examining tool wear. In the case of optical components, the optical properties of the coating are important, but hardness, for example, has a significant advantage if it can improve the resistance of the optical component to scratching. Similarly, in the case of LED components and their enclosures, the essential properties of the coating will certainly include the fluorescence it achieves, but for example, hardness and chemical stability can be greatly advantageous if the LED components are used in demanding conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to exemplary preferred embodiments and the accompanying drawings, in which Figure 1 shows the transmittance of a known carbon nitride coating, Figure 2 shows a basic laser ablation setup, Figure 3 shows another basic laser ablation setup, Figure 5 shows the transmittance of a boron compound doped carbon nitride coating,

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Figure 6 shows another carbon nitride coating doped with a boron compound

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Fig. 7 shows the transmittance of a third boron compound doped carbon nitride coating. Fig. 8 shows a FIB-SEM image of a carbon nitride based coating. Fig. 9 illustrates the proportions of carbon, nitrogen and boron in some of the materials of Fig. 10. Figure 11 illustrates an LED component, Figure 12 illustrates another LED component and an LED component housing, Figure 13 illustrates an optical element, and Figure 14 illustrates a cutting tool.

In the pictures, the same reference numerals are used for like parts.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

10 The following terms and expressions are used in this specification: Nicanite® Graphite Carbon Nitride, manufactured by Carbodeon Ltd Oy, a C3N4 + XHy nanoparticle single diamond crystal having a diameter of a few nanometers, a fluoropolymer having one or more fluorine atoms; for example, a PTFE (polytetrafluoroethylene) LED component is an electronic, visible or near-visible light component containing a pn junction that emits radiation in response to the right electric current passing through it, the housing of an LED component usually made of plastic, rubber or glass. - a cover designed to cover at least a portion of the LED ώ component or the pn junction contained therein and / or to modify the radiation emitted by the LED component;

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wavelength and / or spatial distribution of radiation

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an optical component, usually a single piece device or σ> part of a device the essential function of which is to transmit, reflect, refract or transmit visible m or near visible light; for example, a lens, a mirror, a prism, a surface of a display device or the like 6, a tool for cutting workpieces or materials, the blade of which is intended to penetrate the workpiece and to remove parts thereof; for the purposes of this specification, cutting tools also include knives and similar cutting blades.

PROPERTIES OF THE TARGET MATERIAL

According to a preferred embodiment of the invention, the target material used to coat the substrate by laser bleaching has a graphite carbon nitride and dopant to alter the properties of the coating to be formed as compared to pure carbon nitride. The density of the material at the target used for laser ablation is at least 70% (preferably more than 80%) of the theoretical density of the parent material and the grain size of the dopant is up to 30 micrometers.

The theoretical density of the material ptheory is generally defined by the formula

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P'tkmry ~ y m? L · 'Λ 15 where Nc is the number of atoms in the unit cubicle, A is the atomic weight, Vc is the volume of the unit cubic and N is the number of Avogadro. The density of the target material must be high enough to maintain the target during laser ablation. One preferred method of producing a sufficiently dense target is SPS (spark plasma sintering), also called field assisted sintering technique (FAST). The target can also be manufactured using HIP (hot isostatic pressing) technology or some other method of compacting.

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The maximum requirement for the grain size of the dopant comes from the fact that, when aiming for uniform quality plasma (and especially for reactive plasma), the coating material constituents must be capable of mixing the target so that the target laser pulse always ablates both carbon nitride and a mixture of a detergent or agents. The study leading to the invention has found that

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The spot size of the laser pulse (i.e., the smallest diameter of the area that the laser pulse hits the target) should not generally be made smaller than 30 micrometers.

30 When the lower limit of the spot size of the laser pulse is the same as the upper limit of the grain size of the coating material dopant, it can be assured that no laser pulse ablates the target alone.

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NANOTRANT-ALLOYED CARBON NITROGEN

Figure 2 schematically illustrates the production of a coating by laser-bleaching using carbon nitride target 201 which contains some weight percent nanotubes 202. Such a target can be made, for example, by compacting 5 alloy containing powdered graphite carbon nitride and nanotimes. At the time of writing, both powdered graphite carbon nitride and nano-diamonds are commercially supplied, for example, by Carbodeon Ltd Oy, Vantaa, Finland. The laser beam 203 is applied in pulses to the surface of the target 201, whereupon the target material is released to form a so-called. plasma plu-10 me 204. A portion of the detachable target material hits a nearby surface of the substrate to be coated, thereby forming a coating 206. To coat substrate bodies of significant size, a laser beam 203 is scanned along the surface of the target 201. It is also possible to move the target and / or substrate during coating to coat a larger substrate area.

The target nanotube length by weight may preferably be from 1 to 50%, more preferably from 1 to 20%, and most preferably from 1 to 10%. For example, it may be 2% or 5%. However, coatings can be prepared from carbon nitride targets, which contain a mixture of nanoparticles and nanoparticles (nanoparticulate graphite particles). As shown schematically in Figure 2, the so-called ablative laser beam. the spot, or region on the surface of the target to which the ablating laser beam is applied, is very large in diameter compared to the diameter of a single nanotube. Spots can have tens of micrometres in diameter, whereas a single nanotube has only a few nanometers in diameter. If carbon nitride and nanosized diamonds are mixed with each other evenly during the production of the target,

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The 5 targets can be considered to be essentially homogeneous in terms of laser ablation: ab-

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, it does not matter where the material is

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At the surface of the laser, the ablating laser pulse is applied in each case.

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x One known form of laser blocking is cold blocking, which has the character-

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30 is characterized by the fact that the duration of a single laser pulse is shorter than the time constant of thermal energy transfer in the target material. In other words, the laser pulse releases energy to the target material in the spot area only for such a short time that the released energy cannot advance deeper into the target material by thermal interaction. Virtually all target material at the spot area 35 of the target surface is so-called. up to the ablation depth leaves plasma, leaving behind 8 spot-sized, ablation-deep and very flat craters. In cold blocking, the length of the laser pulse is measured in peak, femto, or attoseconds. The nanosecond laser cannot be used for cold blocking because the pulse length measured in nanoseconds is so large that a significant portion of the 5 pulse energy is absorbed into the target material as thermal energy.

Cold blocking is known to produce very good quality plasma when measured by the absence of splashes and particles: the transfer of energy from the laser pulse energy to the energy of the ablated target material is so sudden and limited to such a small amount of target material that it decomposes into atomic plasma. Therefore, it is surprising that there are ranges of process parameters (especially laser beam power density at the target surface) where the carbon nitride alloying nanoparticles do not completely decompose in the cold blasting process, but their presence in the resulting coating could also be confirmed by optical measurements.

Intentional variations in homogeneity can also be produced in a carbon nitride target doped with nanoparticles. For example, the density of nano-diamonds in a carbon nitride matrix can be made depth-dependent, i.e., the nanotubes content of the target may be different at different depths from the surface of the target. It is known from laser bleaching that the stoichiometry of the coating material retains well, that is, the relative amounts of the various components in the coating repeat very well as they were in the target. Thus, if the target is ablated layer by layer and the relative amount of the alloying agent (here: nanotimes) changes in different layers, the coating can produce a similar relative variation in nanotube content.

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Compared with pure carbon nitride, carbon nitride doped with nano diamonds has a lower ablation threshold in g. In other words, the energy density of the laser pulse, which must exist in the region of the spot in order to release the target material, is small.

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x not. In one experiment, 9.8 was used to ablate the pure carbon nitride site

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30 Watt laser power. when the corresponding ablation was obtained - without changing any other process parameters ™ - from a 0.8 watt nanotube doped carbon nitride target and a 0.35 watt laser power only from a nanothiomantane nanotube doped carbon nitride target.

As a result of the lower ablation threshold, one advantageous feature of nanotube doped carbon linitride in coating production is the good yield: even with relatively low laser power it is possible to produce significant amounts of coating in a short time. The reduced ablation threshold can be utilized to increase the laser spot size because, despite the larger spot, the laser power applied to the target is sufficient to achieve ablation uniformly throughout the spot. Increasing the spot size naturally gives you the opportunity to produce more coating in less time. The lower ablation threshold also makes it easier to produce a good quality (= flat, perforated, and particle-free) coating, because of the low laser power required, for example, laser inaccuracies or scanning do not very easily produce significant deviations from consistent quality.

Coatings made of nanotube doped carbon nitride according to one embodiment of the invention are very hard. The Pencil hardness test has been found to be harder than 10H. The partial magnification shown in Figure 2 provides an explanation for this phenomenon. The nano-diamond terminated on the coating 206 is designated by reference numeral 207 as the difference from the nanotubes 15 202 in the target material. The crystal structure of the nano-diamond 207 is characterized by sp3-type bonds between carbon atoms. When the plasma released by the laser beam from the target begins to cool, the nanotimes (or those sp3 crystalline regions of the plasma derived from the target material nanotubes; the target material nanotimes do not necessarily release into the plasma as such) act as nucleation centers. In coating 206, a proportion of carbon nitride is formed around these 20, where sp3-type bonds are more common than carbon nitride in general. In the partial magnification of Figure 2, this area is designated 208.

Figure 3 schematically illustrates the production of another coating by laser blasting using carbon nitride target 201, which in this case is also shown to contain nanosized diamonds 202. As an alloying agent, however, it is generally said that batch target 201 containing at least carbon nitride and? substances. This is the case here

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9 high power density of the cold blocking laser 303 that a significant portion of the plasma cloud 303 is reactive. In other words, a significant amount of plasma constituents have such high energy that they can retrieve the potential energy

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δ ^ In the arrangement of Figure 3, the coating δ 306 formed on the surface of the substrate 205 does not necessarily consist of the same material

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or from the same materials as the target 201, but phenomena occurring in reactive plasma can produce even molecular structures that are completely unknown. An indication of this would be, for example, the near-perfect visible light transmittance achieved with some boron compound doped carbon nitride targets, which will be described in more detail below.

The embodiment of Figure 3 is also characterized by the advantageous properties of cold ablation, e.g. the fact that in the laser beam spot region, from the surface of the target to the ablation depth, all of the target material is released and converted into plasma. Thus, it can be assumed that the mass proportions of the various elements in coating 306 are the same as in target 201 unless 10 gaseous media are added to the ablation chamber, which would be involved in reactive plasma phenomena. However, it is relatively difficult to study the structure of the resulting coating 306 at the level of the atoms and the bonds between them, so the coatings that are made are often defined by the product-by-process used to produce them.

All in all, nanoparticles used as an alloying agent can produce not only nucleation centers but also atomic carbon in the resulting coating. This creates a certain amount of carbon in the coating structure compared to the C3N4 structure. Chemical processes can take place in the plasma, whereby some of the C3N3 ring structures can be converted into, for example, C4N2 or C5N ring structures. In addition, some of the nitrogen bridges connecting the ring structures may be replaced by carbon.

A 366 nanometer wavelength ultraviolet excitation produces photoluminescent radiation from a pure, sp2-configured carbon nitride coating in the 390-450 nanometer range (see, e.g., Jianjun Wang, Dale R. Miller, Edward G. Gillan, co 25 'Photoluminescent carbon nitride Films grown by vapor). tride powders * CHEM. COMMUN., 2002, 2258-2259). Instead, a coating produced by cold blotting from a nanotube doped carbon nitride deposit on a tex surface produces photoluminescence radiation with a distinct redder composition.

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x nent included so that the photoluminescence can be considered white. The red

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The female component is due to the retention of the nanosized diamonds in the coating and / or the fact that due to plasma energy the structure has created new types of red fluorescent light-producing bonding structures.

δ 00 The presence of a redder component in photoluminescence is observed, at least by using 35 nanotimes produced by detonation (or detonation) as a carbon nitride dopant. Detonation occurs in a chamber charged with a mixture of tri-nitro-toluene (TNT) and cyclo-tri-methylene-tri-nitramine (RDX). The nitrogen content of the explosives causes the nano-diamonds to be nitrogen-containing, so their use as a carbon nitride alloy increases the total nitrogen content of the whole. Relatively high nitrogen content in doped carbon nitride coating improves coating transparency or transmittance at visible light wavelengths

One particularly advantageous property in the photoluminescence of a nanotube doped carbon nitride coating is its good stability. The photoluminescence of the pure carbon nitride coating has been found to remain constant for at least several 10 years, and there is no indication that the photoluminescence of the carbon nitride coating doped with nanotimulants is lower.

CARBON NITRIC COMPOUND WITH A Boron Compound (s)

The coating made from pure carbon nitride by cold blotting typically has a transmissivity of 90-92% at visible light wavelengths and coatings of either clear or slightly yellowish color. However, it has surprisingly been found that the addition of boron nitride or carbide to the carbon nitride target can produce a coating which is very transparent at visible light wavelengths up to coating thicknesses of more than one micrometer, although for example boron nitride in all its forms is white and opaque to visible light. The increase in trans-20 miscibility refers to the emergence of completely new types of nitrogen-rich CBN composite materials through reorganization of the molecular structure in plasma.

Unexpectedly, CBN composite films can be made so that they are both hard and abrasion resistant and elastic at the same time.

Carbon nitride coatings doped with a boron compound or compounds are also useful because of their diffusion-inhibiting properties. In general, coatings which act as diffusion barrier should be of such a dense structure that they prevent both gases and liquids from entering the object to be protected by the coating. In practice, this means that these CU_30 coatings must have no holes or interface between the crystal structures. Optimal diffusion barriers should therefore be structurally amorphous. In addition, high transparency, adjustable refractive index, di-electrical nature, chemical inertness and good heat resistance are typical requirements of industrial diffusion barrier coatings, for example in electronics. Further, 12 if such coatings are applied to polymeric substrates, the coatings should be elastic to prevent release of the coatings when subjected to external pressure.

The use of nitrogen-rich carbon-boron-nitrogen materials (i.e., typ-5-like CBN materials) in coatings is not known in the art. Typically, it has not been possible to prepare coatings from nitrogen-rich forms of materials in the absence of stoichiometric manufacturing methods. An example of the prior art is shown in Figure 4, which shows the transmittance results for BC0.24N0.24 in Douglas B Chrisey, Ruqiang Bao, Zijie Yan: "Transitions of Boron Carbide to BCN Thin Film", Mater.Res.Soc .Symp.Proc., Vol. 1204, 2010. Curve 401 shows the transmittance of a 390 nanometer thick coating of the aforementioned BCN and curve 402 represents the transmittance of a 293 nanometer thick boron carbide film.

Another prior art publication is Q. Yang, C.B. Wang, S. Zhang, 15 D.M. Zhang, Q. Shen, L.M. Zhang, "Effect of Nitrogen Pressure on Structure and Optical Properties of Pulsed Laser deposited BCN Thin Films", Surface & Coatings Technology 204 (2010) 1863-1867, which describes the use of nanosecond laser for boron-based coatings. According to the publication, the maximum nitrogen content achieved by PLD (Pulsed Laser Deposition) 20 is limited to 26% and the transmittance of the coatings produced is within the visible light range to about 80%. In addition, the publication states that when a nitrogen atmosphere is used in the PLD process, a portion of the boron in the target does not end up in the coating to be produced. In other words, according to the aforementioned publication, the method is not stoichiometric.

Figures 5, 6 and 7 show the measured transmittance of a boron nitride doped carbon nitride coating in the case of three different coatings of one embodiment of the invention. Coatings were made on borosilicate glass having the effect of its own cvj transmittance removed from the measurement data shown in Figures 5, 6 and 7.

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x circles. The properties of the coatings are shown in the following table.

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m δ

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13 n Scan-

Thickness Pressure

Image (632.8 Hardness velocity nm mbar nm) mm / s 5 1.73 380 8H 40 4.8-10'6 6 1.70 450 N / A 35 9.0-10'6 7 1.73 1200 8H 30 9.0-10'6

In the table, the second column represents the refractive index of the coating at 632.8 nm, the third column the thickness of the coating, the fourth column the so-called hardness of the coating. on the pencil hardness scale, the fifth column of laser beam spot scan speed on the target surface and the sixth column of pressure in the chamber where the coating was performed. In the target, the ratio of carbon nitride to boron nitride was 9: 1 atomic ratio, and the target was kept at room temperature during ablation (i.e., no separate heating of the target was associated with the ablation). The ablation took 15 to 10 minutes in each case, so differences in coating thickness are explained by variations in scan speed and pressure.

Figure 8 is a FIB-SEM (Focused Ion Beam - Scanning Electron Microscope) image of a cross-sectioned silicon substrate 801 having a surface of about 635-640 nanometers in thickness 802. The coating is produced by cold-blotting a target portion of carbon nitride. The dark zones above the coating 802 are due to the silvering required for the operation of the imaging method. The picture shows that the coating 802 is completely ob amorphous, i.e., it does not show any grain boundaries. Furthermore, the coating 802 is very uniform, and no pinhole was found outside the area of the micrometer 00 20 shown in FIG.

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The CBN composite coatings thus prepared can be used as transparent optical coatings having good mechanical properties (abrasion resistance, m hardness) and low dielectric constant. They also have a diffusion barrier property to prevent the passage of both gases and liquids, so coatings can be used to protect, for example, an electronic, industrial, or household product. Some particularly advantageous applications utilizing the diffusion barrier feature of the CBN coating are Organic Light Emitting Diode (OLED), Thin Film-based Solar Cell Solutions, Home and Industrial Display Solutions for Televisions, Computers and Cell Phones, and Measuring Devices. They can also be used as protective coatings for hard drives 5. Because the CBN coatings produced are also elastic, they can also advantageously be used as functional coatings for polymer-based products.

Like the nanotube alloy, boron nitride alloy has a lowering effect on the carbon nitride ablation threshold. This is very surprising because the ablation threshold for pure boron nitride is higher than the ablation threshold for pure carbon nitride. It has been found in experiments that when the coating was made by cold-blotting from pure carbon nitride at a laser power of 25-30 watts and a scanning speed of 100 mm / s, the required laser power for the corresponding plasma formation was obtained by increasing the boron nitride alloy as follows:

15 - Boron nitride 2% by weight: 32 W laser power

- 5% by weight of boron nitride: laser power <10W

- 10% by weight of boron nitride: 6 W laser power

- 25% by weight of boron nitride: 6,5 W.

Boron nitride, as its name implies, contains boron and nitrogen. Figure 9 is a ternary-20 diagram illustrating the atomic number proportions of carbon, nitrogen, and boron in some materials. White squares indicate boron nitride BN, boron carbide B4C, BC2N (or BCCN) known as superhard material, and pure carbon nitride C3N4. The white circles represent the materials discussed in the above-mentioned Yang et al.

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^ 25 pressure on structure and optical properties of pulsed laser deposited BCN

^ thin Films. " The lined screen shows a mixture of carbon nitride to boron nitride 9: 1. Ellipse 901 shows an area of the ternary diagram which contains interesting coating materials which are cm-carbon mixtures of boron nitride in different alloy ratios.

σ> ^ 30 The measured hardness 8H of a boron nitride doped carbon nitride coating is already quite high, so that such a coating can provide a special advantage in optical components which have to withstand hard processing without scratching. An example of such an optical component is a transparent window or lens covering the display of a portable communication, gaming or computer device. If other alloying agents, such as metal, alkali metal, rare-earth metal and / or alkaline-earth metal, are added to the carbon nitride material of the target, wavelength selectivity can be generated for the target coating.

By changing process parameters, it is possible to produce an even harder coating. The hardness of CBN coatings according to one embodiment of the invention ranging from 30 nanometers to 1200 nanometers was measured by a pencil hardness test of more than 9H. In another batch, CBN coatings of 100-500 na-10 m were produced on silicon, glass and AISI420 steel, and their wear resistance was investigated. POD (Pin On Disk) test. The test used an alumina test head and ran one million cycles. According to the test, the wear of the CBN coatings according to embodiments of the invention was 30-50 times less, depending on the sample, than the wear of the uncoated silicon-15 substrate.

The friction coefficient of a typical CBN coating was measured against alumina. The relative humidity at the time of measurement was 30%. A coefficient of friction of 0.2 was obtained.

Making a boron compound doped carbon nitride coating on a substrate that is significantly hotter than room temperature makes the coating particularly hard, although heating the substrate also tends to diminish the transmittance of the visible boron of the boron compound doped carbon nitride film.

A preferred feature of a boron nitride doped carbon nitride coating according to one embodiment of the invention is its relatively high optical refractive index. Figure 10 is a graph of a measured refractive index. The coating was produced in 9 cases on the silicon substrate by cold blotting from a target containing bo

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™ Rinitride and Carbon Nitride at 25% and 75% by weight, respectively. The picture shows | Given that the refractive index was greater than 2 throughout the visible light wavelength range, 631,8 nanometers, often used as a reference, the refractive index g was 2.0702. In many applications where the optical properties of the coating are relevant, the refractive index is required to be at least

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™ at 1.7 wavelengths of visible light to minimize the refractive index differences between the different parts of the structure (right-35 refractive and lower refractive index in a row, respectively). According to an embodiment of the invention, the refractive index of the carbon nitride doped with boron nitride can be adjusted by changing the proportion and / or process parameters of the boron nitride dopant.

Another boron compound that can be used for carbon nitride alloying is boo-5 sulfur carbide. It is a carbonaceous compound that is naturally high in sp3 bonds, so that it can achieve the same type of UV-excited red-headed fluorescence as the nanotube alloy. Since boron carbide does not contain nitrogen unlike boron nitride, boron carbide as such may be difficult to achieve the advantageous properties of the doped coating due to the presence of ty-10 pen. However, it is possible to carry out a nitrogen-enriched boron carbide blend, for example, so that the target contains carbon nitride and boron carbide, and gaseous nitrogen is added to the air-depleted coating chamber during coating.

The CBN composite coating according to an embodiment of the invention produces a variety of photoluminescent radiation depending on the sp2 / sp3 ratio of the amorphous coating. Quite surprisingly, the intensity of the light produced is strongly dependent on the surface roughness of the coating. The coarser the texture of the coating, the stronger the intensity of the light produced.

The weight percentages of carbon nitride and boron compound in the target material may be, for example, 98% and 2%; or 95% and 5%; or 80% and 20%; or 50% and 50%; or 25% and 75%. Generally, the dopant is boron nitride and / or boron carbide having an atomic proportion of 10 to 90% of the coating material, with carbon nitride having an atomic proportion of 10 to 90% of the coating material.

According to a preferred embodiment of the invention the boron compound or compounds

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Using the target as a dopant and preparing the coating by cold-blasting causes the resulting coating to contain boron, carbon and nitrogen in a so-called.

9 BC2N phase, which may be in the form of amorphous, microcrystalline (crystalline nano- and / or cm-microparticles in an otherwise amorphous phase) or crystalline. Called BC2N- | phase is used from the superphase of boron, carbon and nitrogen, the existence of which has been predicted by calculation (see, e.g., Chunqiang Zhuang,

Jijun Zhao, Xin Jiang: Poster Presentation '' Searching for Superhard Cubic Phases in the BC-N System by First-Principle Calculations '', Chair of Surface and Materials Technology, University of Siegen, http: // www .mb.uni-siegen.de / e / lot /, published at the Diamond 2011 Conference 35 in Garmisch-Partenkirchen on 4-8 September 2011.

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The carbon nitride compound doped with a boron compound can be prepared by the same method as, for example, a carbon nitride dopant doped with nanoparticles, that is, by compacting a mixture of powdered carbon nitride and a powdered boron compound in a suitable ratio. Because different amounts of boron nitride and / or boron carbide can be blended into the carbon nitride target, the invention allows completely new, previously unknown CBN compositions and their advantageous use in various applications.

HYDROGEN COMPOUNDED CARBON NITROGEN

With the CVD method (Chemical Vapor Deposition) 10 DLC coatings with the abbreviation Diamond-Like Carbon. If the coating is based on pure (graphite) carbon, the coating becomes very hard, but its friction properties are typically modest and the surface does not become very smooth. With CVD, it is possible to add 8 to 12% by weight of hydrogen to the DLC coating, making the surface smoother and improving the frictional properties of the surface.

The crystalline structure of graphite carbon nitride is planar, since the carbon atoms form a certain amount of double bonds with the nitrogen atoms, so that the structure is sp2-type and free out-of-plane bonding directions are not found. Addition of hydrogen to graphite carbon nitride causes some of the double bonds to be relaxed into single bonds, with some of the carbon atoms also being bonded to one hydrogen atom. When some of the double bonds are satisfied, the structure becomes more intact and compacted. Simple bonds do not limit bonding directions in the same way as double bonds, which allows more crystal structure to form interlayer bonds as well, and the structure begins to become more sp3-like in co 25. Hydrogen alloying thus means that, strictly speaking, pure graphite carbon nitride can no longer be talked about.

Slightly simpler, the addition of hydrogen during the crystallization step of carbon nitride ™ facilitates the formation of a stable, three-dimensional crystal structure | s. If the crystallization step refers to the adherence of plasma removed from the carbon nitride target by cold ablation and the formation of a coating on the surface of the substrate, the three-dimensionality of the crystal structure helps to obtain an extremely uniform coating. Addition of hydrogen to carbon nitride produces a redder fluorescence light at ultraviolet excitation than that obtained from a pure carbon nitride coating. In addition, the relaxing effect of hydrogen and favoring a three-dimensional crystal structure 35 can improve the transmittance of the coating in the visible light wavelength range 18. Further, the relaxing effect of hydrogen and favoring the three-dimensional crystal structure improves the diffusion barrier properties of the coating, since a coating having a high three-dimensional crystal structure is more diffusion-tight than a coating consisting of planar two-dimensional structures.

According to one embodiment of the invention, the coating is produced such that the base material of the coating is carbon nitride and 1 to 12% by weight of hydrogen is added thereto. One method of producing a hydrogen-doped carbon nitride coating is cold-bleaching, which is directed to carbon nitride, in which air is first pumped out of the coating chamber and then gaseous hydrogen is added to the coating chamber. The partial pressure of hydrogen in the chamber and its relationship to laser power, pulse length, pulse rate, spot size, scan rate, and other process parameters can control how much hydrogen is doped in the coating.

CARBON NITRIC COMPOUND WITH OTHER SUBSTANCES

The doping of carbon nitride with an alkali metal, a rare-earth metal and / or an alkaline-earth metal produces a coating having the fluorescence and / or chromatographic properties characteristic of the dopant. Ceramic, europium, samarium, neodymium, praseodymium, erbium, ytterbium, holmium or terbium may be used as the dopant. If an alkali-20 metal, a rare-earth metal or an alkaline-earth metal is used, its typical weight percentage in the target material is 1-30% or even less than 1%.

Graphite carbon, amorphous carbon, and pyrolytic carbon are almost inevitably present as alloy coatings in all coatings made from the carbon nitride target by laser blasting, since some of the carbon atoms in the plasma generated during the ablation process form these various allotropic forms of carbon when solidified. the target material

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By appropriate selection of process parameters, it can also be achieved that the resulting coating contains an alloying agent containing, in addition to graphitic, 00 amorphous or pyrolytic carbon, nanoparticles.

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Some coatings made of doped carbon nitride may be hydrophilic.

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55 to 30 Pa so disturbingly that the coating is released from the substrate after absorbing too much water from the ambient air. The hydrophilicity of the coating can be reduced (i.e. its hydrophobicity increased) by using a fluoropolymer as a dopant, of which polytetrafluoroethylene is a particularly preferred dopant. The use of a fluoropolymer or fluoropolymers as an alloying agent may also improve the anti-fouling properties of the coating, reduce friction and increase wear resistance. It has been found that the fluoropolymer added in small amounts to the carbon nitride coating is not as heat sensitive as the fluoropolymer itself. The good heat resistance of the fluoropolymer doped carbon nitride coating according to an embodiment of the invention is advantageously influenced by the good thermal conductivity of the carbon nitride material.

Fluoropolymers have a high degree of modifiability in coating materials that, in general, the fluoropolymer used as an alloying agent in a coating material according to one embodiment of the invention has an atomic proportion of from 1 to 99% of the coating material, with carbonitride having from 1 to 99%.

All carbon nitride doping materials and methods disclosed herein are compatible with one another. For example, although the ternary diagram in Figure 5 specifically depicts the relative proportions of only three elements in the coating, it does not mean that the coating may contain substances other than these three. For example, a highly visible light-transmitting coating may be made by doping carbon nitride with boron nitride while maintaining sufficient hydrophobicity of the coating by using a fluoropolymer as the dopant, and further adjusting the chromatographic and / or fluorescence properties of the coating using , praseodymium, erbium, ytterbium, holmium or terbium. The various dopants may be applied homogeneously throughout the coating or layers and / or regions of varying dopant concentrations may be formed on the coating.

CO 25 LED COMPONENT AND LED COMPONENT CASE

Fig. 11 schematically illustrates an LED component having a pn junction semiconductor chip 1101, conductors 1102 connected thereto, and a molded plastic dome 00 1103 for protecting electrical components and directing electromagnetic | radiation generated in the pn junction as a result of the correct electric current, cvj 30 The generation of electromagnetic radiation is called electroluminescence. The other bug 1103 may also be referred to as the housing of the LED component, although it is in this case an integral, integral part of the LED component itself.

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Figure 12 schematically illustrates an LED component in which a plurality of semiconductor chips and 1201 are attached to a common substrate 1202. Wires 1203 provide the necessary conductive connections between semiconductor chips 1201 and semiconductor chips 1201 to the connection areas 1204 on the underside of substrate 1202. fabricated LED component housing 1205 may be mounted on a complete assembly of substrate 1202, semiconductor chips 51201, conductors 1203, and interface portions 1204 such that, in the finished LED component, LED component housing 1205 covers semiconductor chips 1201, shields the electrical components of the LED component, and resulting from the correct electric current in the pn junctions contained in the semiconductor chips 1201.

A single LED component may also have two or more LED component housings (e.g., overlapping or overlapping), or a single LED component housing may comprise two or more LED components in a pre-assembled assembly. The shapes and structures of the LED components and their enclosures shown in Figures 11 and 12 are merely exemplary of a plurality of alternatives and do not exclude the application of the present invention to other types of LED components or other types of LED component enclosures.

A particular pn junction emits electromagnetic radiation only at a specific wavelength, which is determined by the so-called "wavelength" of the semiconductor material. the width of the energy gap. LED-20 components can produce other colored light, but this requires either the simultaneous use of multiple semiconductor chips with different widths of energy gap, or the use of fluorescent conversion material around the semiconductor chip.

Figure 11 is a schematic representation of the coating 1104 on the outer surface of the plastic dome 1103 co 25, which is visible from the primary viewing direction of the light produced by the LED component. The material (s) of the semiconductor chip 1101 are selected such that g electroluminescence produces ultraviolet or near ultraviolet radiation (i.e., radiation of a shorter wavelength than at least most of the visible light). Coating

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x 1104 contains one or more fluorescent materials excited by radiation produced by a semiconductor chip 1101 and produces light visible at the desired wavelength or wavelengths when excited,

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Similarly, Fig. 12 is a schematic representation of the coating 1206, which in this case is on the inner surface of the LED component housing 1205. The concept of operation is the same as in Figure 11, that is, the 35 shorter-wave electromagnetic radiation produced by the electroluminescence of the semiconductor chips 1201 is transformed by the fluorescence phenomenon in the coating 1206 21 into visible light at the desired wavelength or wavelengths. In addition to or instead of the coating solutions shown in Figures 11 and 12, the fluorescent agent may also be mixed with the material from which the LED component housing is made.

5 The fluorescent LED component is known per se, but prior art solutions have often had to rely on fluorescent materials that may have limited availability or have risks or potential drawbacks in their use and handling. Typically, the desired color of the fluorescent light requires the use of various rare earth metals in prior art LED components. These earth metals are only extracted by mining and 90% of their production at the time of writing is China. Due to the limited availability of earth metals, the global, cost-effective and ecologically sustainable deployment of LED components requires novel fluorescence solutions based on commonly available, preferably non-hazardous, elements.

According to an embodiment of the present invention, a coating containing doped carbon nitride is used in the LED component and / or the LED component housing. For example, carbon nitride doped with nano-diamonds and / or boron carbide produces fluorescence radiation when exposed to ultraviolet excitation in such a wide wavelength range of visible light that the fluorescence radiation can be said to be white light. In the absence of excitation, carbon nitride doped with nano-diamonds may, for example, appear to the human eye as dark gray, whereby the use of such a coating can provide interesting and exciting contrasts depending on whether or not the LED component containing the coating is energized.

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§ OPTICAL COMPONENT

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Figure 13 schematically shows a display element 1301 protected by an optical component 1302. In this case, the optical component 1302 is only | a guard designed to allow the image, text, etc. displayed by the display 1301 to be wetted from the main direction of use, i.e., in the case of image 13, from above. In addition, the shield 1302, as its name implies, shields the display 1301 from touch and other environmental influences. Such shields are typically made of 00 transparent plastic or glass and are used in all kinds of electronic devices such as portable communication devices, televisions, computer screens, household appliances, vehicles, toys and so on. Other commonly used optical components include, for example, various lenses (such as spectacle lenses), mirrors, and prisms.

Inexpensive transparent plastics, such as polycarbonate, are often quite soft and scratch-sensitive and may have other properties that are disadvantageous in optical components. It is known per se to use various coatings on optical components to improve, for example, surface wear resistance, reduce harmful reflections, or facilitate cleaning.

Figure 13 schematically shows an optical component coating 1303 of 10 doped carbon nitride. The choice of dopant or substances can achieve a number of very advantageous properties. For example, boron nitride doped carbon nitride coating is very transparent at visible light wavelengths and significantly harder than many commonly used raw materials for optical components, thereby significantly improving the surface wear resistance of the optical component 15. Fluoropolymer blends can create lipophobicity in the coating, reducing the adhesion of grease to the surface, thus reducing the appearance of visible fingerprints (so-called anti-Fingerprint property). By using one or more rare earth metals, alkali metals or alkaline earth metals as the dopant, a wavelength selectivity and / or the desired fluorescence can be produced in the coating.

HOUSING

Although image 13 is described above with particular reference to the optical component, many of the foregoing aspects may be directly generalized to those parts of the enclosures which do not primarily require transparency or other optical features. According to one embodiment of the invention, a coating may be applied to a housing part of a portable or otherwise hand-operable device where fingerprinting is not desired or is not desired.

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cm is more dirt repellent and / or easy to clean.

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£ CUTTING TOOL

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S 30 Some important and worthwhile features in the machining process are the high cutting ability and wear resistance of the cutting tool. Them

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can be improved by coating the cutting tool, or at least the most critical points of its blade, with a coating having good adhesion to the material of the tool or blade, which is suitably hard and has favorable tribological properties.

23

Fig. 14 is a schematic cross-section of a cutting tool blade, in this case a lathe blade. The blade material 1401 is coated with a doped carbon nitride coating 1402, at least to the extent that it comes into contact with the material being processed. The coating may be, for example, a boron nitride doped carbon nitride coating on a warm-to-silent substrate (= blade material) with a hardness of up to 10H on a pencil hardness scale. In addition to, or in place of, boron nitride, carbon nitride doping agent (s) may be used, such as nano-diamonds, other carbon allotropic forms, boron carbide, hydrogen, nitrogen or fluoropolymer.

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Claims (26)

1. Melting material (201) for coating a substrate (205) by laser abrasion, which means contains graphitic carbon nitride and dopant to change the properties of the coating (206, 306) to be formed compared to a pure carbon nitride coating, characterized in that the density of the grinding material (201) is at least 70% and advantageously above 80% of the theoretical density of the grinding material (201) - the particle size of the dopant present in the grinding material (201) is at most 30 microns and - the dopant contains at least one of the following: nanodiamonds (202), boron nitride, boron carbide. Mill material (201) according to claim 1, characterized in that the weight ratio of the nanodiamonds (202) in the mill material (201) is advantageously 1 - 50%, more advantageously 1 - 20% and most preferably 1-10%. Mill material (201) according to claim 1, characterized in that the atomic fraction of boron nitride and / or boron carbide used as a dopant is 10 - 90% of the mill material (201), and the atomic fraction of carbon nitride is 10 - 90% of the mill material (201 ). 20 Melting material (201) according to claim 1, characterized in that the dopant contains a pouring fluoropolymer. δ 5. Mill material (201) according to claim 4, characterized in that the atomic fraction of fluoropolymer used as a dopant is 1-99% of the mill material (201), and the atomic fraction of carbon nitride is 1-99% of the mill material (201). CC 0 0 0 6. Coating (206, 306) containing from a specific template (201) laser-graphite carbon dioxide and dopant produced by laser ablating to change the properties of a coating (206, 306) as compared to a pure carbon nitrite coating, characterized by that the dopant contains one of the following: nanodiamonds (202), boron nitride, boron carbide. Coating (206, 306) according to claim 6, characterized in that the weight ratio of the nanodiamonds (207) in the coating (206, 306) is advantageous 1 -50%, more advantageous 1-20% and most advantageously 1-10%. Coating (206, 306) according to claim 6, characterized in that the sp3-5 crystalline regions, which originate from the nanodiamonds (202) of the molten material (201), form nucleation centers (208), which are surrounded by the carbon nitride portion in the coating (206, 306). ), wherein sp3-type bonds are more general than carbon nitride in general. Coating (206, 306) according to claim 6, characterized in that the atomic fraction of boron nitride and / or boron carbide used as a dopant is 10 - 90. of the material of the coating (206, 306), and the atomic fraction of carbon nitride is 10 - 90. % of the coating (206, 306) material. Coating (206, 306) according to claim 6, characterized in that it contains boron, koi and nitrogen as a BC2N phase. Coating (206, 306) according to claim 6, characterized in that the dopant contains hydrogen. Coating (206, 306) according to claim 6, characterized in that the dopant contains graphitic, amorphous or pyrolytic koi or a mixture containing, for example, graphitic, amorphous or pyrolytic koi, nanodiamonds (202). Coating (206, 306) according to claim 6, characterized in that the dopant contains fluoropolymer. co Coating (206, 306) according to claim 6, characterized in that the dopant contains an unusual soil metal, alkali metal or alkaline earth metal. ώ 15. Coated article, the material of whose coating (206, 306) contains graphical carbon nitride and dopant to change the properties of the coating (206, 306) as compared to a pure carbon nitride coating, characterized in that the dopant contains contains at least one of the following: nanodiamonds (202), boron nitride, boron carbide. σϊ LO 16. Coated article according to claim 15, characterized in that the dopant contains hydrogen. Coated article according to claim 15, characterized in that the dopant contains graphitic, amorphous or pyrolytic koi or a mixture which, in addition to graphitic, amorphous or pyrolytic koi, contains nanodiamonds (202). Coated article according to claim 15, characterized in that the dopant contains 5 fluoropolymer. Coated article according to claim 15, characterized in that the dopant contains unusual soil metal, alkali metal or alkaline earth metal. Coated article according to claim 15, characterized in that it is a clamping tool. Coated article according to claim 20, characterized in that the coating (206, 306) of the clamping tool contains boron, koi and nitrogen as a BC2N phase. Coated article according to claim 15, characterized in that it is an optical element (1302). Coated article according to claim 15, characterized in that it is an LED component. Coated article according to claim 23, characterized in that said LED component is arranged to generate white light. Coated article according to claim 15, characterized in that it is a fluorescent case (1205) for an LED component. Coated article according to claim 25, characterized in that the fluorescent case (1205) of said LED-o component has essentially a white light fluorescence spectrum. CVJ CVJ X cc CL CVJ δ m δ CVJ