INTERFERENCE LAYER SYSTEM WITHOUT A CARRIER SUBSTRATE, METHOD FOR PRODUCING SAME, AND USE THEREOF

Abstract

An interference layer system includes a plurality of optically transparent layers. The interference layer system has no carrier substrate and the optically transparent layers are disposed extensively over one another. The optically transparent layers are selected from the group consisting of dielectrics, metals, and combinations thereof, with at least one first optically transparent layer having a refractive index n.sub.1 and at least one second optically transparent layer having a refractive index n.sub.2, and with the first refractive index n.sub.1 and the second refractive index n.sub.2 differing by at least 0.1. The disclosure further relates to the production and the use of the interference layer system.

Claims

1. An interference layer system, comprising: a plurality of optically transparent layers having no carrier substrate, the optically transparent layers being disposed extensively over one another, wherein the optically transparent layers are selected from the group consisting of dielectrics, with at least one first optically transparent layer having a refractive index n.sub.1 and at least one second optically transparent layer having a refractive index n.sub.2, and with the first refractive index n.sub.1 and a second refractive index n.sub.2 differing by at least 0.1, wherein a reflection curve of the interference layer system in a wavelength range from 300 nm to 800 nm has at least two regions of different reflection, wherein the interference layer system contains no purely metallic layers and no layers containing elemental metal, wherein an overall thickness of the interference layer system is from 40 nm to 5 μm, wherein the reflection curve of the interference layer system has a reflection of at least 70% at least in a first region of at least 60% of a full width at half maximum (FWHM), wherein FWHM=(0.6.Math.λ.sub.0)−170 nm, with λ.sub.0=380 nm to 600 nm, wherein a calculation of the FWHM has a relative error of 10%, wherein the reflection curve of the interference layer system is determined for nonpolarized light in an incident angle range from 0° to 15°, and wherein the reflection curve of the interference layer system has a reflection of ≤20% at least in a second range from ≥1.1.Math.λ.sub.0 to ≤800 nm.

2. The interference layer system as claimed in claim 1, wherein a layer thickness of each optically transparent layer is in a range from 5 nm to 500 nm.

3. The interference layer system as claimed in claim 1, wherein the optically transparent layers each contain a metal oxide in an amount of 95 to 100 wt %, based in each case on a total weight of the respective optically transparent layer.

4. The interference layer system as claimed in claim 1, wherein the interference layer system has at least 2 low-index optically transparent layers having the refractive index n.sub.1<1.8 and at least 2 high-index optically transparent layers having the refractive index n.sub.2≥1.8.

5. The interference layer system as claimed in claim 1, wherein the interference layer system comprises or consists of 4 to 100 optically transparent layers.

6. The interference layer system as claimed in claim 1, wherein a low-index optically transparent layer has the refractive index n.sub.1 in a range from 1.3 to 1.78, and wherein the low-index optically transparent layer is selected from the group consisting of silicon oxide, aluminum oxide, magnesium fluoride, and mixtures thereof.

7. The interference layer system as claimed in claim 1, wherein a high-index optically transparent layer has the refractive index n.sub.2 in a range from 2.0 to 2.9, and wherein the high-index optically transparent layer is selected from the group consisting of titanium oxide, iron oxide, niobium oxide, tantalum oxide, zirconium oxide, chromium oxide, cerium oxide, cobalt oxide, and mixtures thereof.

8. The interference layer system as claimed in claim 1, wherein each optically transparent layer consists of a metal oxide.

9. The interference layer system as claimed in claim 1, wherein the interference layer system comprises at least 20 optically transparent layers, and wherein a refractive index difference between two adjacent optically transparent layers is at least 0.90.

10. The interference layer system as claimed in claim 1, wherein the interference layer system has a same reflection property in a range of up to 10 percentage points of the regions corresponding to one another in the following optical entry and exit media: air with a refractive index at 550 nm of n=1.000; or water with a refractive index at 550 nm of n=1.330; or oily/fatty substances with a refractive index at 550 nm of n=1.400.

11. A method for producing an interference layer system as claimed in claim 1, the method comprising: providing an extensive carrier substrate material; applying a release layer; applying a plurality of optically transparent layers to generate the interference layer system; and detaching the interference layer system from the extensive carrier substrate material.

12. The method as claimed in claim 11, further comprising: applying the optically transparent layers by vapor deposition.

13. The method as claimed in claim 11, further comprising: forming the release layer from a water-soluble inorganic salt.

14. An optical filter, wherein the optical filter is or comprises the interference layer system as claimed in claim 1.

15. An application medium comprising: the interference layer system as claimed in claim 1.

16. An interference layer system comprising: at least 20 optically transparent layers disposed in alternation over one another and having respectively different refractive indices, wherein a reflection curve of the interference layer system in a wavelength range of 300 nm and 800 nm has at least two regions of different reflection, and at least one wavelength range of these at least two wavelength ranges has a reflection of at least 70% in a region of at least 60% of the full width at half maximum (FWHM), where FWHM=(0.6.Math.λ.sub.0)−170 nm, wherein λ.sub.0=380 nm to 600 nm, wherein the reflection curve of the interference layer system is determined for nonpolarized light in an incident angle range from 0 to 15°, wherein the interference layer system contains no purely metallic layers and/or layers containing elemental metal, and wherein an overall thickness of the interference layer system is from 40 nm to 5 μm, and wherein at least one region, which is different from the at least one wavelength range of these at least two wavelength ranges, has a reflection of ≤20% in a range from ≥1.1.Math.λ.sub.0 to ≤800 nm.

17. The interference layer system as claimed in claim 16, wherein exactly one wavelength region of the at least two wavelength regions has a reflection of at least 70% in a region of at least 60% of the FWHM.

18. The interference layer system as claimed in claim 16, wherein a refractive index difference between two adjacent optically transparent layers is at least 0.90.

19. The interference layer system as claimed in claim 16, wherein the interference layer system has a surface roughness of ≤3 nm rms.

20. The interference layer system as claimed in claim 16, wherein the interference layer system has a layer sequence 0.227 T/1.097 L/0.661 T/0.793 L/1.109 T/0.668 L/1.083 T/0.922 L/0.810 T/0.971 L/1.012 T/0.708 L/1.153 T/1.055 L/0.611 T/0.939 L/1.340 T/0.263 L/1.458 T/1.564 L, with the optical layer thicknesses in λ.sub.0/4, with a refractive index for Tat 550 nm of n=2.420, and a refractive index for L at 550 nm of n=1.468.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0199] The disclosure will now be described with reference to the drawings wherein:

[0200] FIG. 1 shows a calculated reflection curve of an interference layer system of the disclosure composed of a total of 26 layers of TiO.sub.2 and SiO.sub.2 disposed in alternation;

[0201] FIG. 2 shows the interference layer film of the disclosure or an interference layer foil of the disclosure, for which the reflection curve from FIG. 1 was calculated and measured, on a scanning electron microscope slide;

[0202] FIG. 3 shows an SEM micrograph (SEM: scanning electron microscope) of the interference layer film of the disclosure for which the reflection curve from FIG. 1 was calculated and measured, and which can be seen in FIG. 2; and

[0203] FIG. 4 shows the reduction in the transmission in the wavelength range between 350 nm and 800 nm when using an interference layer system for which the reflection curve from FIG. 1 was calculated and measured and which can be seen in FIG. 2 and FIG. 3, respectively.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0204] An extensive substrate material in the form of a plastic substrate coated with a polysiloxane-based hardcoat material MP-1154D (SDC TECHNOLOGIES, INC.) was disposed as carrier substrate material in accordance with manufacturer data in a Satisloh 1200-DLF coating unit.

[0205] The plastic substrate material was an uncoated spectacle lens made of CR39 polymer and having a circular diameter of 6.5 cm and a thickness in the middle of 1.5 mm. First of all the primer PR-1156 (SDC TECHNOLOGIES, INC.) had been applied by dip-coating in a layer thickness of 750 nm to the plastic substrate material. Drying took place for 5 min at a temperature of 70° C. in a ULE 600 vertical oven from Memmert GmbH+Co. KG, D-91126 Schwabach. The polysiloxane-based hardcoat material MP-1154D had been subsequently applied in a layer thickness of 2500 nm by dip coating. Drying and curing then took place for 120 min at a temperature of 110° C. in a ULE 600 vertical oven from Memmert GmbH+Co. KG D-91126 Schwabach.

[0206] Before the actual deposition of the layer materials commenced, the surface was bombarded with ions in vacuum at a pressure of less than 8×10.sup.−4 mbar. The ions came from an End-Hall-type ion source. This ion source is part of the coating unit. The ions were Ar ions with an energy of between 80 eV and 130 eV. The ion current density reaching the substrates was between 20 and 60 μA/cm.sup.2. Bombardment with Ar ions took place for 2 minutes.

[0207] After the end of Ar ion bombardment, a layer of NaCl 30 nm thick was first applied in a high vacuum without reactive gas to the hardcoated plastic substrate material, using the electron beam evaporator in the Satisloh coating unit, at a pressure of 4×10.sup.−4 mbar and a deposition rate of 0.2 nm/s. Subsequently a total of 26 layers of TiO.sub.2 and SiO.sub.2 were applied in vacuum under a pressure of 4×10.sup.−4 mbar. During the coating of the TiO.sub.2 layers, oxygen was added as reactive gas (20 sccm), so that the layers grew without absorption in the visible spectral range and were therefore optically transparent. During the deposition of the TiO.sub.2, the substrate was also bombarded with ions. These ions came from an End-Hall-type ion source. This ion source is part of the coating unit. The ions were oxygen ions with an energy of between 80 eV and 130 eV. The ion current density reaching the substrates was between 20 and 60 μA/cm.sup.2. The bombardment of the growing TiO.sub.2 layer with oxygen ions, like the addition of reactive gas, was a contributing factor to the growth of the TiO.sub.2 layers in the form of an optically transparent layer. Here, layers of TiO.sub.2 and layers of SiO.sub.2 were applied in alternation. The first metal oxide layer applied directly to the NaCl release layer was a TiO.sub.2 layer. The respectively applied layer thickness of the TiO.sub.2 layer and SiO.sub.2 layer is reported in [nm] in Table 2.

TABLE-US-00008 TABLE 2 t/nm Substrate CR39 Primer PR-1156 750 Hardcoat MP-1154D 2500 Release layer NaCl 30  1 TiO.sub.2 8.6  2 SiO.sub.2 73.2  3 TiO.sub.2 25.1  4 SiO.sub.2 52.9  5 TiO.sub.2 42.1  6 SiO.sub.2 44.5  7 TiO.sub.2 41.1  8 SiO.sub.2 61.5  9 TiO.sub.2 31.0 10 SiO.sub.2 64.5 11 TiO.sub.2 37.8 12 SiO.sub.2 51.5 13 TiO.sub.2 41.9 14 SiO.sub.2 62.0 15 TiO.sub.2 30.7 16 SiO.sub.2 64.7 17 TiO.sub.2 38.4 18 SiO.sub.2 47.2 19 TiO.sub.2 43.7 20 SiO.sub.2 70.4 21 TiO.sub.2 23.2 22 SiO.sub.2 62.6 23 TiO.sub.2 50.8 24 SiO.sub.2 17.5 25 TiO.sub.2 55.3 26 SiO.sub.2 104.3 t/nm: Thickness in [nm]

[0208] The respective layer thickness was set via the duration of vapor deposition, in accordance with manufacturer details relating to the coating unit. The layer thickness here was determined using a quartz crystal oscillator system (XTC Controller, Inficon, CH-7310 Bad Ragaz) which measures the change in the frequency of an electrical crystal oscillator, the frequency changing with the layer thickness of the growing interference layer system. The crystal oscillator is coated onto the plastic carrier substrate during the coating procedure, in an analogous way, and the change in frequency thereof is measured at the same time. The reflection curve calculated for the interference layer system with a total of 26 layers (see Table 2) is shown in FIG. 1.

[0209] A measurement was carried out in order to monitor the applied coating: the reflection curve was measured using the F10-AR-UV reflection spectrometer from Filmetrics, Inc. (San Diego, Calif. 92121, USA), with the measurement head, after calibration of the instrument according to manufacturer instructions, being placed onto a coated region of the plastic carrier substrate directly after production of the interference layer system. This measurement was made within 5 minutes after admission of air to the vacuum coating unit, when coating had been ended. The reflection curve was measured on the interference layer film still adhering to the plastic carrier substrate, since it is complicated to measure a reflection curve on an interference layer film detached from the plastic carrier substrate.

[0210] The layer thicknesses applied in each case were calculated using the OptiLayer software program, version 12.37, from OptiLayer GmbH. For the purposes of calculation of the target reflection curve, a factor taken into account was that the interference layer system of the disclosure, during the measurement as well, was disposed over the release layer, hardcoat layer and primer coat on the carrier substrate material. For the calculation, therefore, a target reflection curve was input initially. The software program possessed algorithms which calculate interference layer systems, taking boundary conditions into account. The algorithm selected for the calculation was “gradual evolution.” The boundary conditions stipulated were the substrate material, the primer coat with its optical properties and layer thickness, the hardcoat layer with its optical properties and layer thickness, the release layer of NaCl with its optical properties and layer thickness, and the use of TiO.sub.2 and SiO.sub.2 as layer materials. The maximum number of layers was limited to 26. The algorithm optimized the number of layers and their thickness until a minimum deviation relative to the target curve was achieved. A result of this optimization were the layer thicknesses reported in Table 2. The results of the measured reflection curve agreed with the calculated target reflection curve. Accordingly, the interference layer system detached from the carrier substrate also had the calculated/measured reflection curve.

[0211] After the end of the coating operation, the coated substrates were removed from the coating unit and left to stand in the laboratory at room temperature for 5 hours. The relative atmospheric humidity in the laboratory was more than 30%. The interference layer film or interference layer foil was then removed from the substrate surface using tweezers. As a result of intrinsic stresses, the interference layer film or interference layer foil rolled itself up, as shown in FIG. 2.

[0212] FIG. 3 shows an SEM micrograph (SEM: scanning electron microscope) of the interference layer film of the disclosure. The individual layers of TiO.sub.2 and SiO.sub.2 are clearly perceptible. In order to determine the effect in a coating material of relatively high viscosity, approximately 1% by mass of the detached interference layer film was incorporated into glycerol with stirring. The stirring produced comminution of the interference layer film, to give interference layer particles. A film of the interference layer particle-containing glycerol was then applied to a slide in a layer thickness of 50 μm, and the spectral transmission in the wavelength range from 350 nm to 1050 nm was measured using an Ultrascan Spectrophotometer from Hunter Associates Laboratory, Inc. 11491 Sunset Hills Road, Reston, Va. 20190-5280, USA. In order to calculate the contribution of the interference layer particles alone, a glycerol film without interference layer particles was subjected to measurement beforehand.

[0213] In FIG. 4, the change in transmission, delta T, resulting from the addition of the interference layer particles is plotted. This was calculated as the difference between the transmission curves with and without interference layer particles in glycerol.

[0214] From FIG. 4 it is apparent that the addition of the interference layer particles of the disclosure resulted in a significant reduction in transmission within a wavelength range <430 nm, whereas the transmission at longer wavelengths was not affected.

[0215] The average particle size of the interference layer particles of the disclosure in glycerol, with glycerol being used as a model of a viscous coating system, was determined under an optical microscope and found to be about 40 μm.

[0216] When the concentration of the interference layer particles in glycerol was increased, a further reduction in the transmission was possible.

[0217] The foregoing description of the exemplary embodiments of the disclosure illustrates and describes the present invention. Additionally, the disclosure shows and describes only the exemplary embodiments but, as mentioned above, it is to be understood that the disclosure is capable of use in various other combinations, modifications, and environments and is capable of changes or modifications within the scope of the concept as expressed herein, commensurate with the above teachings and/or the skill or knowledge of the relevant art.

[0218] The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “having” or “including” and not in the exclusive sense of “consisting only of.” The terms “a” and “the” as used herein are understood to encompass the plural as well as the singular.

[0219] All publications, patents and patent applications cited in this specification are herein incorporated by reference, and for any and all purposes, as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference. In the case of inconsistencies, the present disclosure will prevail.