Coated Object and Method for Producing a Coated Object

Abstract

A coated object and a method for producing a coated object are disclosed. In an embodiment, the coated object includes a substrate and an optical coating disposed on the substrate, wherein the optical coating includes a reflection-reducing layer sequence, which includes a covering layer with a refractive index n.sub.A and at least one diamond layer with a refractive index n.sub.D1>n.sub.A, wherein the diamond layer is disposed between the covering layer and the substrate and includes diamond crystals, and wherein the diamond layer has a layer thickness of less than 500 nm.

Claims

1-11. (canceled)

12. A coated object comprising: a substrate; and an optical coating disposed on the substrate, wherein the optical coating comprises a reflection-reducing layer sequence, which comprises a covering layer with a refractive index n.sub.A and at least one diamond layer with a refractive index n.sub.D1>n.sub.A, wherein the diamond layer is disposed between the covering layer and the substrate and comprises diamond crystals, and wherein the diamond layer has a layer thickness of less than 500 nm.

13. The coated object according to claim 12, wherein the reflection-reducing layer sequence has a reflectance of less than 1% in a wavelength range of 420 nm to 680 nm, wherein the diamond layer is disposed between the covering layer and a second layer with a refractive index n.sub.2<n.sub.D1, wherein the covering layer and the diamond layer are in direct mechanical contact and/or wherein between the diamond layer and the covering layer a first layer with a refractive index n.sub.1 is disposed, and wherein the following applies: n.sub.D1>n.sub.2>n.sub.1.

14. The coated object according to claim 12, wherein the layer sequence further comprises one or more pairs of layers, which are disposed directly after the substrate, wherein each of the one or more pairs of layers comprises a first layer with a refractive index n.sub.1 and a second layer with a refractive index n.sub.2>n.sub.1, wherein the diamond layer is disposed between a first layer and a second layer of a pair of layers, and wherein the following applies: n.sub.D1>n.sub.2>n.sub.1 and n.sub.1n.sub.An.sub.2 and n.sub.D1>n.sub.2+x*0.6 with 0.1x1.

15. The coated object according to claim 12, wherein the layer sequence further comprises one or more pairs of layers, which are disposed directly after the substrate, wherein each of the one or more pairs of layers comprises a first layer with a refractive index n.sub.1 and a second layer with a refractive index n.sub.2>n.sub.1, wherein the diamond layer is disposed between a first layer and a second layer of a pair of layers, and wherein the following applies: n.sub.D1n.sub.2>n.sub.1 and n.sub.1n.sub.An.sub.2.

16. The coated object according to claim 12, wherein the layer sequence further comprises one or more pairs of layers, which are disposed directly after the substrate, wherein each of the one or more pairs of layers comprises a first layer with a refractive index n.sub.1 and a second layer with a refractive index n.sub.2>n.sub.1, wherein the diamond layer is disposed directly after the one or more pairs of layers, wherein over the diamond layer the covering layer is disposed, and wherein the following applies: n.sub.D1>n.sub.2>n.sub.1 and n.sub.1n.sub.An.sub.2 and n.sub.D1>n.sub.2+x*0.6 with 0.1x1.

17. The coated object according to claim 12, wherein the layer sequence further comprises one or more pairs of layers, which are disposed directly after the substrate, wherein each of the one or more pairs of layers comprises a first layer with a refractive index n.sub.1 and a second layer with a refractive index n.sub.2>n.sub.1, wherein the diamond layer is disposed directly after the one or more pairs of layers, wherein over the diamond layer the covering layer is disposed, and wherein the following applies: n.sub.D1n.sub.2>n.sub.1 and n.sub.1n.sub.An.sub.2.

18. The coated object according to claim 12, wherein the layer sequence has at least five layers and/or no more than twelve layers, and wherein the diamond layer has a homogeneous layer thickness with a layer thickness of less than or equal to 300 nm.

19. The coated object according to claim 12, wherein the covering layer is formed using crystalline aluminum oxide and has a layer hardness, measured with a nanoindenter, of greater than 20 GPa and/or the diamond layer has a layer hardness of greater than 60 GPa.

20. The coated object according to claim 12, wherein the covering layer comprises aluminum oxide, silicon dioxide, aluminum nitride, silicon nitride, crystalline aluminum oxide and a mixture of Al.sub.2O.sub.3 and SiO.sub.2, Si.sub.3N.sub.4 or AlN.

21. The coated object according to claim 12, wherein the layer sequence is capable of transmitting radiation with a dominant wavelength , and wherein for a thickness of the diamond layer, 0.3 /4n.sub.D1*d.sub.D10.8 /4 applies, for a thickness of the covering layer, 0.7 /4n.sub.A*d.sub.A1.3 /4 applies, for a thickness of a first layer, 0.7 /4n.sub.1*d.sub.11.3 /4 applies, and for a thickness of a second layer, 0.7 /4n.sub.2*d.sub.21.3 /4 applies.

22. The coated object according to claim 12, wherein the layer sequence further comprises at least one additional diamond layer with a refractive index n.sub.D2, which is disposed between covering layer and substrate, wherein the at least two diamond layers of the layer sequence are each separated from one another by a first layer with a refractive index n.sub.1 and/or a second layer with a refractive index n.sub.2, wherein the covering layer is disposed directly after one of the diamond layers, and wherein the following applies: n.sub.D1>n.sub.1+0.8 and n.sub.D2>n.sub.1+0.8 and/or n.sub.D1>n.sub.2+0.4 and n.sub.D2>n.sub.2+0.4 and/or n.sub.D1=n.sub.D2.

23. A method for producing a coated object according to claim 12, the method comprising: providing the substrate, and applying the reflection-reducing layer sequence, wherein the at least one diamond layer is produced by a vapor deposition, and wherein, afterwards, the covering layer is produced by magnetron sputtering.

24. The method according to claim 23, wherein the vapor deposition and the magnetron sputtering are carried out in one apparatus.

25. The method according to claim 23, wherein the vapor deposition is plasma-enhanced CVD.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0061] FIG. 1 shows a schematic diagram of a coated object according to one embodiment;

[0062] FIG. 2 shows a schematic diagram of a coated object according to one embodiment;

[0063] FIG. 3 shows the reflectance in per cent as a function of the wavelength in nm of a comparative example and of two exemplary embodiments; and

[0064] FIG. 4 shows a schematic diagram of a coated object according to one embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0065] In the exemplary embodiments and figures, identical or similar elements or elements having the same effect can be provided with the same reference numbers. The elements illustrated and the size ratios to one another thereof should not be considered as being to scale. Rather, to illustrate them better and/or to make them easier to understand, the size of individual elements, such as e.g. layers, may be exaggerated. In particular, the layers or the layer thicknesses illustrated are not to scale.

[0066] FIG. 1 shows a schematic side view of a coated object 100. The coated object 100 contains a substrate 1. The substrate 1 can be composed of e.g. glass or sapphire. On the substrate, a first layer 6 with a refractive index n1 is then disposed. The first layer 6 can comprise or consist of e.g. silicon oxide or silicon dioxide. The first layer 6 is followed by a second layer 7 with a refractive index n2. The second layer 7 can consist of e.g. aluminum oxide or can comprise aluminum oxide. The second layer 7 is followed by a further first layer 6, which can in turn comprise in particular silicon oxide or silicon dioxide. This further first layer 6 is in turn followed by a further second layer 7, which can comprise e.g. aluminum oxide. The coated object 100 thus comprises as optical coating 2 a reflection-reducing layer sequence 3 having two pairs of layers, which are disposed after the substrate 1 and each comprise a first layer 6 and a second layer 7. These two pairs of layers are followed directly by a diamond layer 5, i.e. they are in direct mechanical contact therewith. In particular, the diamond layer 5 has a layer thickness of 50 nm to 150 nm, e.g. 130 nm. The diamond layer 5 is directly followed by a further first layer 6, which contains e.g. silicon oxide or silicon dioxide. This further first layer 6 is followed by the covering layer 4 as the uppermost layer. The covering layer 4 can contain e.g. crystalline aluminum oxide or a mixture of aluminum oxide and silicon dioxide to reduce the refractive index. The coated object 100 according to FIG. 1 thus contains a layer sequence 3 consisting of seven layers. The layer sequence 3 can in particular have a layer thickness of 540 nm in total. Thus, a coated object 100 can be provided having a scratch-resistant, hard, antireflective coating 2 for at least the visible range of the spectrum.

[0067] FIG. 2 shows a coated object 100 according to one embodiment. The coated object 100 contains a substrate 1. The substrate 1 is followed by a layer sequence 3 of an optical coating 2. The layer sequence 3 comprises two second layers 7 each with a refractive index of n2. One of the two second layers 7 is disposed directly on the substrate 1. The second layer 7 is followed by a first layer 6 with a refractive index n1. The first layer 6 is followed by a further second layer 7. The further second layer 7 is followed by a diamond layer 5. The diamond layer 5 is followed by a covering layer 4. The covering layer 4 is the outermost layer of the optical coating 2. Thus, the diamond layer 5 is the penultimate layer 5 of the optical coating 2, directly below the covering layer 4. The coated object 100 according to FIG. 2 thus contains a layer sequence 3 consisting of five layers. The total thickness of the optical coating 2 can be approximately 540 nm. The covering layer 4 contains in particular crystalline aluminum oxide and silicon dioxide. Silicon dioxide is added particularly in order to reduce the refractive index of aluminum oxide (1.7).

[0068] FIG. 3 shows a graphic representation of the reflection or reflectance R in per cent (%) as a function of the wavelength in nanometers (nm).

[0069] Graph A shows the reflectance in per cent of the exemplary embodiment of FIG. 1. In particular, the coated object 100 according to FIG. 1 has a reflectance R of <1%, in particular less than 0.8%, in the visible range, i.e. between 420 nm and 680 nm.

[0070] Graph B shows the reflectance or reflection in per cent of the exemplary embodiment of FIG. 2. The coated object 100 according to FIG. 2 shows a reflectance R of between 1.8% and 3% in the visible range of the spectrum between 420 and 520 nm. Between 520 nm and 580 nm, R is between 0.8% and 1.8%. In the wavelength range of 580 to 640 nm, the exemplary embodiment of FIG. 2 has a reflectance R of less than 1%. Between 640 and 68 nm, the reflectance is less than 2%.

[0071] FIG. C shows the reflectance in per cent of sapphire in a wavelength range of 360 nm to 800 nm. Sapphire shows a reflectance of about 8%. All the reflection values relate to one side, i.e. without taking account of rear side reflection. Reflection or reflectance refers here and below to the ratio between reflected and incident intensity.

[0072] FIG. 4 shows a schematic diagram of a coated object 100 according to one embodiment. The coated object 100 displays a substrate 1. On the substrate 1, an optical coating 2 with a reflection-reducing layer sequence 3 is disposed. The layer sequence 3 contains two diamond layers 5, 8. The first diamond layer 5 is disposed directly below the covering layer 4. The two diamond layers 5, 8 are each separated from one another by a first layer with a refractive index n1 and/or a second layer with a refractive index n2 6, 7. The following applies in particular here: nD1>n1+0.8 and nD2>n1+0.8 and/or nD1>n2+0.4 and nD2>n2+0.4 and/or nD1=nD2.

[0073] In particular, the first layer 6 is formed using silicon dioxide. In particular, the second layer 7 is formed using aluminum oxide. The covering layer 4 is in particular formed using crystalline aluminum oxide. Alternatively, it is also possible to introduce more than two diamond layers 5, 8 in a coated object 100. For example, three, four, five or six diamond layers can be introduced in a coated object. In particular, the production of the diamond layer by means of hot-filament vapor deposition is particularly complex here. It is therefore preferable to introduce as few diamond layers as possible into a coated object 100.

[0074] The exemplary embodiments described in association with the figures and the features thereof can also be combined with one another according to further exemplary embodiments, even if these combinations are not shown explicitly in the figures. Furthermore, the exemplary embodiments described in association with the figures can have additional or alternative features according to the description in the general part.

[0075] The description with the aid of the exemplary embodiments does not limit the invention thereto. Rather, the invention comprises any new feature and any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination is not itself explicitly stated in the patent claims or exemplary embodiments.

[0076] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.