Black items

Abstract

To provide a black-colored article which is easy to handle, robust, and cleanable.SOLUTION: A black-colored article (1) which is not a photovoltaic device comprises: a substantially transparent substrate (3); a substantially transparent textured layer (5) provided upon a first surface (3a) of the substrate, and having a textured surface (5a) oriented away from the substrate (3); and an absorption layer (7) comprising a silicon-germanium alloy, the absorption layer (7) situated upon the textured surface (5a) of the textured layer (5).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to timepiece components (particularly, but not exclusively, watch dials), jewelry elements, optical devices, The present invention relates to the technical field of black articles, such as stray light absorbing elements for containers. More particularly, the present invention relates to Such an article is easy to handle, strong and cleanable. [Background technology]

[0002] A fairly intense black article is useful in many technical sectors, especially in watchmaking and optics. In the former case, a dark, non-shiny black watch face provides a contrast with the light-colored hands, etc. This improves the readability of the time display and reduces reflections, which is highly desirable. The theory is that the Panerai Radiomir diving watch dates back to at least the 1930s. This diving watch is finished in a matte black finish to maximize readability. It combines a dial with luminous markings.

[0003] More recently, the document U.S. Patent Application No. 2018 / 157214 (Patent Document 1) describes a clock The use of carbon nanotubes as part of the black coating for the dial The carbon nanotube is particularly suitable for applications where light is parallel to the axis of the carbon nanotube. Such coatings absorb light quite well when the coating is applied to the varnish. Conventional amorphous carbon-based coatings are dispersed in water or coated directly onto a substrate. It is more absorbent than lamp black (also known as carbon black) and has a higher There is no stream.

[0004] However, such carbon nanotube-based coatings are very brittle and The coating cannot be touched or cleaned without damaging it. This causes considerable difficulties in manufacturing and handling because the coating of the dial This is because only the uncoated side can be handled. Accidental contact with the dial can damage the coating to the point that it becomes unusable. There is a risk of injury and it must be discarded.

[0005] Photodetectors, spectrometers, monochromators, microscopes, cameras, baffles for space instruments, etc. In the case of optical instruments, such nanotube coatings can adversely affect optical measurements. The same problem applies equally to the inside of the case to eliminate possible stray light. circle.

[0006] However, the cathode sputtering method described in U.S. Pat. No. 4,997,538 (Patent Document 2) A more physically robust coating, such as a chrome-plated coating or black anodizing of the aluminum substrate, Some existing alternative solutions are optically inferior to carbon nanotube-based coatings. and is therefore a poor alternative if a deep black color is desired. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent No. 2018 / 157214 [Patent Document 2] U.S. Patent No. 4,997,538 [Patent Document 3] U.S. Patent No. 9,726,786 [Patent Document 4] International Publication No. 2008112047 [Patent Document 5] German Patent Application No. 102015114877 [Patent Document 6] U.S. Patent No. 9,817,155 Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to at least partially overcome the above-mentioned disadvantages of the prior art. That is the thing. [Means for solving the problem]

[0009] More particularly, the present invention relates to a black article as defined in claim 1. A photovoltaic device This item is not (i.e. is not a solar cell). a substantially transparent substrate, such as, for example, glass, sapphire, alumina, polymer, etc.; - Directly or indirectly disposed on a first surface of the substrate and directed away from the substrate; a substantially transparent textured layer having a textured surface; - a silicon-gel substrate located directly or indirectly on the textured surface of the textured layer; A light absorbing layer containing an arsenic alloy. This light absorbing layer is typically an undoped absorber since it is not part of the photovoltaic device. Furthermore, the light absorbing layer is typically a homogenous single layer.

[0010] Silicon-germanium alloys, with or without hydrogen, are known to emit light in the visible range, especially It strongly absorbs light in the longer red wavelength range, giving the article a deep black color when viewed from the substrate side. The black color comes from the layer that is on the opposite side to the viewer. Minor damage to the free surface of the layer caused by handling is not visible and is not visible to the substrate (or to any part placed on the substrate). The surface of any further layers (such as anti-reflection and / or scratch-resistant layers) is strong and It is resistant to damage and easily cleaned by conventional mechanical and / or chemical means. The textured surface of the steel layer diffuses the incident light and interacts with the silicon-germanium layer. These two elements work synergistically together, allowing more of the incident light to be absorbed by the Si-Ge layer. , ensuring that a fairly deep black colour is imparted to the article.

[0011] Advantageously, the silicon-germanium alloy contains at least 2% germanium, preferably Preferably, the germanium content is at least 10%, more preferably at least 20%. and more preferably substantially 30% germanium.

[0012] Advantageously, the article further comprises an anti-reflective layer interposed between said substrate and said textured layer. This anti-reflective layer helps to reduce specular reflections and therefore the black of the article. As an example, silicon oxynitride may be used for this anti-reflective layer, The antireflective layer may also be multi-layered with a graded index of refraction that increases through the thickness of the antireflective layer.

[0013] Advantageously, the anti-reflective layer may exhibit a refractive index that exceeds that of the substrate, This improves the suppression of specular reflection.

[0014] Advantageously, an anti-reflective coating may be provided on the second face of said substrate, said second is opposite the first surface and therefore faces in the intended viewing direction. This further reduces specular reflections.

[0015] Advantageously, the anti-reflective coating exhibits a refractive index lower than that of the substrate. This also reduces specular reflections.

[0016] Advantageously, the textured layer may exhibit a refractive index lower than that of the light absorbing layer. , which similarly reduces specular reflection.

[0017] Advantageously, the silicon-germanium alloy layer is between 400 and 700 nm, preferably and / or the texture layer may have a thickness between 550 and 675 nm. , having a thickness between 0.5 and 5 μm, preferably between 2.5 and 3 μm, The substrate has a surface rms roughness of at least 10 nm rms (root mean square) on the substrate surface.

[0018] Advantageously, the texture layer may comprise zinc oxide and / or tin oxide. The above mentioned texture does not require any further steps during the deposition of such a textured layer. They form automatically during deposition without any need for a dummy electrode.

[0019] The black articles are, for example, (non-photovoltaic) dials, hands, gears, springs or other parts for timepieces. Other timepiece parts such as bridges, decorative elements such as watch cases, crowns, bezels, necklaces , collar decoration, ring, bracelet, earring, pendant or brooch, etc. Jewelry elements or sensors, such as light capture elements, optical baffles or beam stopping surfaces, etc. Other applications include light absorbing elements for optical devices such as phones, tablets, etc. Or aesthetic cover glass for electronic devices in general, or home furniture, interior decoration Other decorative elements for automobiles, car decorations, etc.

[0020] The present invention also relates to a method for producing such a black article, the method comprising the steps of: - providing a substantially transparent substrate; - forming, directly or indirectly, a substantially transparent textured layer on a first surface of said substrate; The textured layer has a textured surface facing away from the substrate. having the steps of: A layer containing a silicon-germanium alloy is directly formed on the textured surface of the textured layer. forming the first conductive layer directly or indirectly; Includes.

[0021] This silicon-germanium alloy-containing layer provides all of the above-mentioned additional features already disclosed. This layer is entirely or mainly composed of a Si-Ge alloy. The layer may be hydrogenated, thus forming a Si-Ge:H layer.

[0022] Advantageously, the substantially transparent textured layer is chemically treated with zinc oxide and / or tin oxide. During deposition of the texture layer, for example during evaporation, the surface texture is automatically formed from the material. Thus, the texture may be formed during the deposition step. This eliminates the need for the extra step of generating a

[0023] Alternatively, the above-mentioned textures may be achieved by mechanical texturing and / or chemical etching, etc. Chemical texturing (by ion etching) and / or laser etching This texture can be applied by ablation. The method may be probabilistic or non-probabilistic, depending on the method used to determine the probability of detection.

[0024] Advantageously, the substantially transparent substrate may be provided with an anti-reflective layer, the anti-reflective layer For example, in the case of using a prefabricated glass or polymer substrate, a prefabricated layer may be applied to the second surface of the substrate. It is provided in.

[0025] Advantageously, the method comprises the steps of: forming a textured layer on the first layer of the substrate; The method may further include forming an antireflection layer.

[0026] Advantageously, the light absorbing layer is deposited as an undoped layer and / or as a single homogeneous layer.

[0027] Further details of the invention will become apparent from the following description taken in conjunction with the following drawings: There will be. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic cross-sectional view of an article according to the present invention in its simplest form. [Diagram 2] 3 is a schematic cross-sectional view of a further variant of the article according to the invention; [Figure 3a] 1 is a graph of total reflectance for various different article samples according to the present invention. [Figure 3b] 1 is a graph of the diffuse reflectance of various different article samples according to the present invention. [Figure 4] 2 is a schematic cross-sectional view of yet a further variant of the article according to the invention; [Diagram 5] 1 is a schematic diagram of three advantageous uses of the article according to the invention; [Figure 6] 1 is a schematic diagram of a method for manufacturing an article according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] FIG. 1 shows a schematic cross-sectional view of a black article 1 according to the present invention in its simplest form. The article 1 may be a watch face, a jewelry element, a light-absorbing element for an optical instrument, or a substantially light-absorbing Item 1 may be a photovoltaic device, i.e. a solar cell. In other words, article 1 is substantially photovoltaically inactive and is not photovoltaically active when exposed to light. The article 1 is not adapted to generate or deliver an electrical current when applied to the article 1. The optical fiber has a substantially transparent substrate 3, which may be made of glass, polymer, sapphire or alumina. The material may be made of a transparent ceramic such as, for example, a glass ceramic, or any other convenient material. In this document, "substantially transparent" means that at least 95% of visible light (350-70%) is transmitted through the glass. 50 nm wavelength) and all refractive indices given are for visible light wavelengths. Although the substrate 3 and the resulting article are shown as flat, It may be curved or formed into any desired shape.

[0030] The intended direction of viewing (shown diagrammatically by an eye symbol representing the viewer's point of view) A substantially transparent textured layer 5 is provided on a first surface 3a of the substrate 3 facing away from the substrate. The texture layer 5 may be disposed directly on the first surface 3a as shown in FIG. or based on one or more supplemental layers, as will be explained in more detail in the context of FIG. 2 below. It may be indirectly disposed on the first surface 3a by being interposed between the body 3 and the textured layer 5.

[0031] The texture layer 5 is formed on the surface 3a of the substrate 1 by, for example, chemical vapor deposition (CVD). ZnO layer, as shown in FIG. 1, from the substrate 3a as shown in FIG. The surface 5a of the texture layer 5 facing away from each other is formed in a shape of a plurality of pyramids. Another particularly suitable material for this layer is CVD-deposited tin oxide, which is transparent and sharply defined. It has a more rounded surface morphology than the pyramidal shaped zinc oxide. Other materials exhibiting similar properties are possible. It is Noh.

[0032] Depositing different materials that do not inherently form textured surfaces, such as transparent polymers and alumina It is also possible to texture the surface 5a in a separate step afterwards. Chamfering can be done mechanically (e.g. machining, grinding, abrasive brushing, sand blasting, bead by laser blasting, ion etching, laser etching or laser This can be done by ablation or by chemical etching.

[0033] Alternatively, the surface 3a of the substrate itself may be textured. In the case where the surface 5a of the texture layer 5 is made of a material that does not essentially form a textured surface, Even the patterned pattern is transferred to the surface 5 a of the texture layer 5 .

[0034] How the texture is formed is not important, but ideally the texture should be It should have a minimum rms value of 0 nm and may be stochastic or non-stochastic In particular, values ​​between 15 nm and 500 nm rms are most useful. RMS roughness is measured using the ASM This is described in the EB46.1 standard and is therefore well known to those skilled in the art.

[0035] Regardless of how the texture layer 5 is formed, the thickness of the texture layer 5 is ideally 0. It is between 5 and 5 μm thick, preferably between 2.5 and 3.0 μm thick.

[0036] A light absorbing layer 7 of silicon-germanium alloy is formed on the surface 5a of the texture layer 5. The light absorbing layer 7 contains at least 2% germanium, preferably at least 10% or 2 0% germanium, more preferably 20% to 40% germanium, even more preferably The layer contains essentially 30% germanium, the remainder being the actual The absorber layer is essentially all silicon and hydrogen (SiGe:H). 0 to 700 nm, more particularly between 550 and 675 nm, typically is deposited directly on the texture layer 5, although an intervening layer is also possible.

[0037] Silicon-germanium alloys absorb visible light wavelengths particularly strongly and have a high refractive index of about 3-4. The refractive index of the textured layer 5 is also typically much higher than that of the textured layer 5. The refractive index of the textured layer 5 is about 2. Therefore, the textured layer 5 is The departing visible light is recycled within the light absorbing layer 7 by multiple reflections, thus resulting in maximum absorption. It will be said.

[0038] Therefore, the refractive index is determined from the substrate 3 (or from the anti-reflective coating 9, if present). It is possible to arrange the various layers so as to increase the Si-Ge layer 7, so that Minimize specular reflections.

[0039] In this structure, and in all structures disclosed herein, the light absorption layer 7 is made of a semiconductor material. Note that this is the only layer that is formed and present. Item 1 is not a photovoltaic device. Since the light absorbing layer 7 is not photovoltaically active, i.e., photovoltaically inactive, it is typically an undoped layer. (i.e., intrinsic type), but does not exclude that P-type or N-type dopants may be present. In addition, the article may include PN, NP, PIN, NI, etc., which are formed by various doping, etc. There is no P or other type of photovoltaically active junction. Essentially, the Si-Ge of layer 7 The fact that it is a semiconductor is coincidental, since layer 7 was chosen for its light absorbing properties. Layer 7 is typically a single substantially homogenous layer, and may also be a laminate. Note also that this is not a more complicated configuration, since it allows This ensures that deposition of the 7 can be performed quickly and efficiently in a single process step, resulting in a significant cost savings. This is to bring about economical manufacturing.

[0040] FIG. 2 shows a further variant of the black article 1 in which two further measures to improve the blackness have been implemented. However, it is entirely possible to apply one or the other measure individually.

[0041] Layers 3, 5 and 7 are described above and need not be described again.

[0042] The first way to make the color darker is the presence of an anti-reflective coating 9. The tinsel 9 faces in the direction that is intended for viewing, i.e., from the Si-Ge alloy layer 7. It comprises one or more layers applied on the surface of the substrate 3 facing away. This surface is referred to as the "second This is defined as "3b"

[0043] This anti-reflective coating 9 may also be scratch and abrasion resistant, such that Such coatings are well known per se, in particular in the field of spectacles, and provide specular reflection and therefore optical This is an example of the method described in U.S. Pat. No. 9,726,786 (Patent Document 3), International Publication No. No. 2008112047 (Patent Document 4), German Patent Application No. 102015114877 (Patent Document 5), U.S. Patent No. 9,817,155 (Patent Document 6), and countless other documents. Alternatively, if the anti-reflective coating 9 is poorly scratch-resistant, etc., a further A scratch resistant coating (not shown) may be applied over the anti-reflective coating 9 .

[0044] In the context of the present invention, the anti-reflection coating advantageously has a refractive index lower than that of the substrate 3. It has a low refractive index, which reduces back reflections and therefore helps to intensify colors.

[0045] A second approach to deepen the color is to add an additional anti-reflection layer 11 between the substrate 3 and the texture layer 5. This layer is typically formed by interposing a refractive index between the substrate 3 and the texture layer 5. For example, between 10 and 200 nm, more preferably between 70 The silicon oxynitride layer may have a thickness of between 100 nm and 90 nm. The silicon layer may be a multilayer that exhibits a stepwise increasing refractive index towards the Si—Ge layer 7 .

[0046] 3a and 3b show a pair of graphs illustrating the effect of the present invention, with five different samples The percentage of reflected light relative to total and diffuse reflection as a function of the wavelength of incident light is given by The average results for five different samples in the 450-740 nm wavelength range are shown below. The following are listed from left to right and top to bottom in the legends of each graph in Figure 3a and Figure 3b: .

[0047] [Table 1]

[0048] In each case, the thickness of the anti-reflective coating 9 is about 70-90 nm, The thickness of the substrate 3 is about 0.5 mm, and the thickness of the antireflection layer 11 is about 80 nm. The thickness of the ZnO layer 5 is about 2.5 μm, and the thickness of the SiGe light absorption layer 7 is about 625 nm. be.

[0049] As can be clearly seen, the results compare favorably with the diffuse and non-diffuse cases with less than 1% reflectance. Always similar, both the anti-reflective coating 9 and the anti-reflective layer 11 in combination When used, it helps reduce the total reflection to just over 1% (sample e). represents a fairly deep black color.

[0050] In addition, color measurements were taken of the four samples. The color parameters were perceptually uniform and human-like. L correlates with the eyes of * a * b * In this model, L * is the luminance (L * =0 From a certain black L * = 100 (up to white), * is the green-red scale (a * =-128 From green to a * = +127) and b * is the blue-yellow scale (b * =- 128 is blue to b * = +127 to yellow. Therefore, perfect black is L * =a * =b * = 0. The sample is the SCI (" The specular reflection (specular reflection) mode (i.e., total reflection), and the diffuse reflection (SCE) mode (specular reflection) which contains only the diffuse reflection component. The measurements were taken simultaneously in "reflected light excluded" mode. In each case, standard illuminant D65 was used. A 10° observer field of view was used.

[0051] The general results were as follows:

[0052] [Table 2]

[0053] As can be seen from these figures, the samples are quite dark and the anti-reflective coating 9 and layer 11 reduces the specular component without substantially changing the color value. In conventional black articles, the black color appears as a lacquer or coating on the surface facing the viewer. On the other hand, the light absorbing layer 7 is arranged away from the incident light direction, which makes the result even more surprising. It is something.

[0054] Thus, the light-absorbing layer 7 is not disposed on the surface of the article 1 that faces the viewer, and therefore is not visible during handling. In fact, this light-absorbing layer 7 is invisible to the user and can withstand superficial damage. It is even possible to provide a light-absorbing layer 7 on the back side of the article 1 facing away from the user. The substrate 3 and the anti-reflective coating and / or the scratch-resistant coating are Any coatings on the substrate 3, such as coating 9, are on the user-facing side of the article 1 and therefore It can be easily handled and cleaned with conventional mechanical and chemical products without damaging the light-absorbing layer 7. There is no risk of contamination or affecting the optical properties of the article. Cleanability (and resistance to corrosion) In order to maximize the scratch resistance, the second surface 3b of the substrate 3 and / or the second surface 3b of the substrate 3 are The outermost surface of any coating 9 to be applied should ideally have a thickness of 5 nm rms, more particularly 1 The maximum surface roughness is less than nm rms.

[0055] FIG. 4 shows an embodiment of an article 1 corresponding to the article 1 shown in FIG. 2, in which: Several further optional measures have been taken. These measures, either individually or in combination, 10. The anti-reflective coating 9 and / or the anti-reflective layer 11 may be applied. is equally possible.

[0056] Firstly, the light absorbing layer 7 can be protected on the underside of the article 1 by a further protective layer 13, The further protective layer 13 is made, for example, of an encapsulant and is disposed over the light absorbing layer 7 so as to protect the light absorbing layer 7. is deposited on top.

[0057] Furthermore, a relief pattern 3c is provided on one or both of the surfaces of the base body. The pattern may be, for example, a regular pattern, an imprint, an image, etc. , may extend above a major surface of the substrate 3 or may be recessed into said major surface. The height and / or depth may be at least 1 mm above and / or below the main surface of the substrate 3, as appropriate. μm.

[0058] It should also be noted that additional layers, such as diffusion layers, may be incorporated as desired. When such a layer is disposed between the texture layer 5 and the Si-Ge alloy layer 7, the texture is so that the surface of the Si-Ge alloy layer 7 facing the body 3 is still textured. Note the permutation through this extra layer.

[0059] FIG. 5 shows a schematic representation of three possible non-limiting application examples of the article 1 according to the invention. On the left side of the figure, a timepiece 21 is shown in which the object 1 is used as a dial 22, and the base of the object 1 is 3 faces the user when the user wants to view the time.

[0060] In the middle of FIG. 5, the article 1 is a bracelet, a pendant, a brooch, an earring, etc., as a decorative element. It is incorporated into accessories such as yarrings.

[0061] On the right side of FIG. 5, the article 1 is incorporated into an optical sensor 25 that comprises a housing 26. The optical sensor 29 is disposed in the cavity 27. ... The article 1 faces the shutter 31 and receives no unwanted light other than the light passing directly from the shutter 31 to the sensor 29. The substrate 3 is configured to absorb light that is difficult to absorb, and faces the inside of the housing and / or the shutter 31. The articles are placed in each section of the article 1 facing in the opposite direction.

[0062] Of course, other applications are possible.

[0063] With regard to the manufacturing steps, FIG. 6 shows diagrammatically the manufacture of an article 1 corresponding to the article 1 of FIG. The article 1 according to FIG. 1 or one or the other of the antireflective coating 9 or the antireflective layer 11 In the case of an article where a method has been removed, the corresponding method steps are simply removed.

[0064] First, a substrate 3 is prepared to serve as a base on which all other layers are formed. Such materials have been described in detail above and will not be repeated here.

[0065] Anti-reflective coatings 9, if present, are described, for example, in US Pat. No. 5,399,633, US Pat. No. 5,493,363, US Pat. No. 5,493,625, US Pat. No. 5,523,396, 5, US Pat. No. 5,399,623, or countless other publications, at any convenient time during the process. It is not necessary that it is the first layer deposited on the second surface 3b of the substrate 3. However, Commercially available glass and plastic substrates already equipped with anti-reflective coatings are available off-the-shelf In practice, an anti-reflective coating layer is often deposited first because it is possible to Thus, when depositing other layers, the anti-reflective coating layer is already present on the substrate 3. do.

[0066] Next, an anti-reflective layer 11, if present, is deposited on the first surface 3a of the substrate 3. As a typical example, the anti-reflective layer 11 may be a silicon oxynitride layer, which may be oxidized under the following conditions: 13.56MHz plasma excitation frequency, 15mm electrode distance, 45×55cm electrode surface dimensions The film is deposited by plasma-assisted chemical vapor deposition in a reactor having a thickness of It will be said.

[0067] [Table 3]

[0068] A texture layer 5 is then deposited directly or indirectly on the first surface 3a. When the tea layer 5 is made of zinc oxide, the texture layer 5 is formed by the above-mentioned reaction under the following conditions: It can be deposited by low pressure chemical vapor deposition in a reactor to the thicknesses given below.

[0069] [Table 4]

[0070] The texture layer 5 is different from ZnO, which does not have a proper surface texture as a result of deposition. When made from a material, it is mechanically, chemically, optically or ionically configured as described above. Good too.

[0071] Next, the Si-Ge alloy light absorbing layer 7 is grown in the above-mentioned reactor under the following conditions, for example, by plasma Deposited directly or indirectly on the surface of the textureless layer 5 by laser-assisted chemical vapor deposition, as shown Brings thickness.

[0072] [Table 5]

[0073] Of course, other intermediate or outer layers may be deposited as desired.

[0074] Although the invention has been described with reference to specific embodiments, the following claims Variations to these specific embodiments may be made without departing from the scope of the invention as defined. is possible.

Claims

1. A black article (1) which is not a photovoltaic device, said black article (1) comprising, in order: a transparent substrate (3), an antireflection layer (11) provided on a first surface (3a) of said substrate, said antireflection layer (11) having, in the provided state, a second surface adjacent to said first surface (3a) of said substrate and a first surface remote from said first surface (3a) of said substrate; a transparent textured layer (5) provided on a first side of said antireflection layer (11), said textured layer (5) having, in the provided state, a second side adjacent to the first side of said antireflection layer (11) and a first side remote from the first side of said antireflection layer (11), and further having a textured surface (5a) on said first side of said textured layer (5); a light absorbing layer (7) comprising a silicon-germanium alloy provided on the textured surface (5a) of the textured layer (5); Equipped with The black article (1), wherein the material of the anti-reflective layer (11) and the material of the textured layer (5) are different.

2. The black article (1) according to claim 1, wherein the silicon-germanium alloy contains at least 2% germanium.

3. 3. The black article (1) according to any one of claims 1 to 2, further comprising an anti-reflective coating (9) provided on a second surface (3b) of the substrate (3), the second surface (3b) being opposite the first surface (3a), the anti-reflective coating (9) exhibiting a refractive index lower than the refractive index of the substrate (3).

4. 4. The black article (1) according to any one of claims 1 to 3, wherein the textured layer (5) exhibits a refractive index lower than the refractive index of the light absorbing layer (7).

5. 5. The black article (1) according to any one of the preceding claims, wherein the light absorbing layer (7) has a thickness between 400 and 700 nm.

6. 6. The black article (1) according to any one of claims 1 to 5, wherein the textured layer (5) has a thickness between 0.5 and 5 μm and a surface rms roughness of at least 10 nm on the textured surface (5a).

7. 7. The black article (1) according to claim 6, wherein the textured layer (5) comprises zinc oxide and / or tin oxide.

8. The article (1) comprises: - Timepiece dials, -Timepiece hands, wheels, springs or bridges; - watch cases, watch crowns, watch bezels, decorative elements for household furniture, interior decoration or automotive decoration, - jewellery elements for necklaces, collars, rings, bracelets, earrings, pendants or brooches, - light trapping elements, optical baffles, or light absorbing elements for optical devices such as beam stopping surfaces; - Decorative cover glass for phone, tablet or electronic device 8. The black article (1) according to any one of claims 1 to 7, which is one of the following:

9. The black article (1) according to any one of the preceding claims, wherein the light absorbing layer (7) is a non-doped layer.

10. The black article (1) according to any one of the preceding claims, wherein the light absorbing layer (7) is a single layer.

11. A method for producing a black article (1) which is not a photovoltaic device, the method comprising the steps of: - providing a transparent substrate (3), - forming an anti-reflective layer (11) on a first surface (3a) of said substrate, said anti-reflective layer (11) having a second surface adjacent to said first surface (3a) of said substrate and a first surface remote from said first surface (3a) of said substrate; - forming a transparent textured layer (5) on a first side of said anti-reflective layer (11), said textured layer (5) having a second side adjacent to the first side of said anti-reflective layer (11) and a first side remote from the first side of said anti-reflective layer (11) and having a textured surface (5a) on said first side of said textured layer (5); - forming a light absorbing layer (7) comprising a silicon-germanium alloy on said textured surface (5a) of said textured layer (5); Including, A method, wherein the material of the anti-reflection layer (11) and the material of the texture layer (5) are different.

12. The method according to claim 11, wherein the transparent textured layer (5) is made of a material that automatically develops a surface texture during deposition of the textured layer (5).

13. 13. The method of claim 12, wherein the transparent textured layer (5) comprises zinc oxide or tin oxide deposited by chemical vapor deposition.

14. The transparent textured layer (5) - mechanical texturing, - Chemical texturing, - ion etching, - Laser ablation The method of claim 11 , further comprising applying a texture to the surface of the image by one or more of the following:

15. The method according to any one of claims 11 to 14, wherein the transmissive substrate (3) has an anti-reflection coating (9) provided on the second surface (3b) of the substrate (3).

16. The method according to any one of claims 11 to 15, wherein the light absorbing layer (7) is an undoped layer and / or a single layer.

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