Spectacle lens with filter effect for blue light and spectacles

Abstract

A spectacle lens for an eye of a wearer of spectacles has a front surface and a back surface, wherein the front surface of the spectacle lens faces away from the eye and the back surface of the spectacle lens faces the eye. The spectacle lens includes an optical lens substrate made of or containing mineral glass and/or organic glass, wherein the spectacle lens has at least one first antireflection coating and at least one second antireflection coating, wherein the at least one first antireflection coating has a filter effect for blue light. Further, spectacles containing the spectacle lens are also disclosed.

Claims

1. A spectacle lens for an eye of a spectacle wearer, having a front surface and a back surface, the front surface of the spectacle lens facing away from the eye and the back surface of the spectacle lens facing the eye, and the spectacle lens having an optical lens substrate made of or including a mineral material and/or an organic material, the spectacle lens comprising: at least one first antireflection coating; and at least one second antireflection coating, the at least one first antireflection coating having a filter effect for blue light in a wavelength range from 430 nm to 530 nm or in a wavelength range from 400 nm to 500 nm, a reflectivity curve of the first antireflection coating respectively having, in a wavelength range from 430 nm to 530 nm or in the wavelength range from 400 nm to 500 nm, a reflectivity maximum with a full width at half maximum (FWHM) ranging from 20 nm to ≤55 nm, the at least one first antireflection coating having a transmission from 70% to 100% in a remaining wavelength range of the visible light between 380 nm and 780 nm, the filter effect for blue light being in a range from 5% to 40% in the wavelength range from 400 nm to 500 nm or in the wavelength range from 430 nm to 530 nm.

2. The spectacle lens as claimed in claim 1, wherein a reflectivity of the at least one first antireflection coating has a value of luminous reflectance pursuant to DIN EN ISO 13666:2013-10, section 15.7 of <3.5%.

3. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light has at least two optically transparent layers, the optically transparent layers being arranged extensively over one another, the optically transparent layers essentially consisting of metal oxide or a plurality of metal oxides, 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 the first refractive index n.sub.1 and the second refractive index n.sub.2 differing by at least 0.1.

4. The spectacle lens as claimed in claim 3, wherein the low refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light have a refractive index n.sub.1 within a range from 1.3 to 1.78.

5. The spectacle lens as claimed in claim 4, wherein the low refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light are selected from the group consisting of silicon oxide, aluminum oxide, and magnesium fluoride, or a mixture thereof.

6. The spectacle lens as claimed in claim 3, wherein the high refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light have a refractive index n.sub.2 within a range from 2.0 to 2.9.

7. The spectacle lens as claimed in claim 6, wherein the high refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light are selected from the group consisting of titanium oxide, iron oxide, niobium oxide, tantalum oxide, zirconium oxide, chromium oxide, cerium oxide, and cobalt oxide, or a mixture thereof.

8. The spectacle lens as claimed in claim 3, wherein the low refractive index and high refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light are arranged alternately over one another.

9. The spectacle lens as claimed in claim 3, wherein a layer thickness of each optically transparent layer of the at least one first antireflection coating with a filter effect for blue light is in a thickness range from 5 nm to 500 nm.

10. The spectacle lens as claimed in claim 3, wherein the low refractive index and high refractive index optically transparent layers of the at least one first antireflection coating with the filter effect for blue light are arranged adjoining one another.

11. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light has at least 2 low refractive index optically transparent layers with a refractive index n.sub.1<1.8 and at least 2 high refractive index optically transparent layers with a refractive index n.sub.2≥1.8.

12. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light has optically transparent layers which essentially consist of metal oxide(s) and which each contain metal oxide(s) in an amount of 95 to 100% by weight, in each case in relation to an overall weight of the respective optically transparent layer.

13. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light has or consists of 4 to 100 optically transparent layers.

14. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light reduces the transmission for blue light at 464 nm or at 450 nm through the spectacle lens, in each case in a range from at least 5% to no more than 40%.

15. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light is arranged on the front surface of the spectacle lens and the at least one second antireflection coating is arranged on the back surface of the spectacle lens.

16. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light reduces the transmission for blue light at 464 nm or at 450 nm through the spectacle lens, in each case in a range from at least 5% to no more than 40% and in each case has a maximum yellow value G pursuant to DIN 6167 (January 1980) of no more than 12.

17. The spectacle lens as claimed in claim 1, wherein the at least one first antireflection coating with the filter effect for blue light has a diffusivity which ensures absorption of water molecules passing through the first antireflection coating into the lens substrate and release of water molecules from the lens substrate through the first antireflection coating, from an air atmosphere disposed on a side of the antireflection coating facing away from the lens substrate, and which is associated with a moisture current density which, starting from an equilibrium state of an amount of water molecules stored in the lens substrate in an air atmosphere at 23° C. and 50% relative humidity, brings about settling of an equilibrium state of the amount of the water molecules stored in the lens substrate in an air atmosphere at 40° C. and 95% relative humidity within a time interval which is not longer than the time interval required for the settling of this equilibrium state under corresponding conditions in a case of an uncoated lens substrate that is identical to the lens substrate by more than a time period of length Δt=10 h.

18. The spectacle lens as claimed in claim 17, wherein the time interval has a time period of length Δt=9 h or Δt=8 h or Δt=7 h or Δt=6 h or Δt=5 h or Δt=4 h or Δt=3 h or Δt=2 h.

19. The spectacle lens as claimed in claim 17, wherein the time interval has a time period of length Δt=1 h.

20. A method for producing a spectacle lens as claimed in claim 1 with at least a filter effect for blue light, the method comprising the following steps: (a) providing an optical lens substrate with a front surface and a back surface; (b) optionally, applying a primer layer to the front surface and/or the back surface; (c) optionally, applying a hardcoat layer to the primer layer or directly to the front surface and/or back surface of the optical lens substrate; (d) applying the at least one first antireflection coating with a filter effect for blue light in the wavelength range from 430 nm to 530 nm or in the wavelength range from 400 nm to 500 nm, to the front surface or the back surface; (e) applying the at least one second antireflection coating, to the surface opposite to the at least one first antireflection coating; and (f) optionally, applying at least one further layer.

21. The method as claimed in claim 20, wherein the at least one first antireflection coating with the filter effect for blue light in the wavelength range from 430 nm to 530 nm or in the wavelength range from 400 nm to 500 nm is applied to the front surface, and the at least one second antireflection coating is applied to the back surface.

22. A spectacle lens for an eye of a spectacle wearer, having a front surface and a back surface, the front surface of the spectacle lens facing away from the eye and the back surface of the spectacle lens facing the eye, and the spectacle lens having an optical lens substrate made of or including a mineral material and/or an organic material, the spectacle lens comprising: at least one first antireflection coating; and at least one second antireflection coating, the at least one first antireflection coating having a filter effect for blue light in a wavelength range from 430 nm to 530 nm or in a wavelength range from 400 nm to 500 nm, a reflectivity curve of the first antireflection coating respectively having, in the wavelength range from 430 nm to 530 nm or in the wavelength range from 400 nm to 500 nm, a reflectivity maximum with a full width at half maximum (FWHM) ranging from 20 nm to ≤55 nm, the at least one first antireflection coating having a transmission from 70% to 100% in a remaining wavelength range of the visible light between 380 nm and 780 nm, and a reflectivity of the at least one first antireflection coating having a value of the luminous reflectance pursuant to DIN EN ISO 13666:2013-10, section 15.7 of <3.5%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure will now be described with reference to the drawings wherein:

(2) FIG. 1 shows the spectral curve of the relative effectiveness of the suppression of the formation of melatonin as a function of wavelength;

(3) FIG. 2 shows the spectral curve of the emission of a white LED for lighting purposes;

(4) FIG. 3 shows the spectral curve of the emission of two smartphone screens;

(5) FIG. 4 shows the melatonin suppression as a function of illuminance;

(6) FIG. 5 shows the transmission (Ta) curve and reflection (Ra) curve of a spectacle lens according to the disclosure; and

(7) FIG. 6 shows the reflection curves of an antireflection coating with a filter effect for blue light and an antireflection coating without a filter effect for blue light.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

(8) The transmission and reflection curves shown in FIGS. 4 to 6 relate to an optical angle of incidence of 0°. The calculated and/or measured values of the transmission curves and/or reflection curves apply up to an optical angle of incidence of at least 20°, without the characteristics of the spectacle lens according to the disclosure changing significantly. This angular range covers the range of the main viewing directions through a spectacle lens.

(9) FIG. 1 shows the inhibition of melatonin synthesis as a function of the spectral distribution of the blue light component in humans, as known from the related art. The maximum inhibition of melatonin synthesis occurs at 464 nm.

(10) FIG. 2 shows the spectral curve of the emission of visible light from a white LED for lighting purposes. The normalized intensity maximum of the blue light component is in the region of around 464 nm.

(11) FIG. 3 shows the spectral curves of the light emitted by the screen of a Samsung Galaxy S8® and by the screen of an iPhone® 6s (manufacturer: Apple Inc.), respectively. Here, too, the intensity maximum is in the region of around 464 nm.

(12) FIG. 4 shows the percentage inhibition of melatonin synthesis (in short: melatonin suppression) as a function of illuminance at eye level. This curve is a sigmoid curve, with a virtually linear relationship with the percentage inhibition of melatonin synthesis between 100 lux and 1000 lux. The inhibition saturates, that is to say transitions into a plateau region, above an illuminance of approximately 1000 lux. Consequently, the inhibition of melatonin synthesis between 100 lux and 1000 lux, in particular between 100 lux and 500 lux, can be influenced significantly by filtering the blue light component in a region of around 464 nm.

(13) FIG. 5 shows the transmission curve and reflection curve of a spectacle lens according to the disclosure which was produced according to an exemplary embodiment according to the disclosure. The spectacle lens is provided with a primer layer and a hardcoat layer on both sides. The antireflection coating according to Example 1 which has a filter effect for blue light is applied to the front surface of the spectacle lens and the antireflection coating according to Example 6 which has no filter effect for blue light is applied to the back surface. The spectacle lens according to the disclosure has a virtually constant transmission over a wavelength range from approximately 400 nm to 800 nm. The transmission is attenuated by approximately 20% around 464 nm. This attenuation is not noticeable by a spectacle wearer under daylight conditions, and so the color perception of the spectacle wearer is not impaired, for example by way of a spectral change. The reflection curve correspondingly shows the proportion of reflected blue light.

(14) FIG. 6 shows a comparison of the reflection curves of the antireflection coating according to Example 1, which has a filter effect for blue light, and the antireflection coating according to Comparative Example 6, which has no filter effect for blue light. It is quite evident that the antireflection coating according to Example 1 significantly reduces the blue light component around 464 nm on account of an increased reflection, whereas the antireflection coating according to Comparative Example 6 does not bring about any substantial reduction in the blue light component.

EXAMPLES

(15) The plastics substrate material was a finished spectacle lens made of the polythiourethane polymer (MR-8, Mitsui Chemical, Inc.) and having a circular diameter of 6.5 cm and a thickness in the middle of 1.5 mm. According to DIN EN ISO 13666:2013-10, paragraph 8.4.6, a finished spectacle lens is a spectacle lens with two finished optical surfaces. First of all, a polysiloxane-based hardcoat according to U.S. Pat. No. 6,538,092 B1, Example 1, had been applied by dip-coating in a layer thickness of 2500 nm to the plastic substrate material. 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, Germany.

(16) The finished spectacle lens coated with the hardcoat was then arranged in the 1200-DLF coating system, Satisloh GmbH, D-35578 Wetzlar, Germany, in accordance with the manufacturer's instructions.

(17) Before the actual deposition of the layer materials commenced, the surface was bombarded with ions in vacuo 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.

(18) Application of an Antireflection Coating with a Filter Effect for Blue Light

(19) Subsequently, a total of 10 and 11 layers of TiO.sub.2 and SiO.sub.2, respectively, were applied in vacuo at a pressure of 4×10.sup.−4 mbar to the front surface of the finished spectacle lens on which the hardcoat had been provided, as specified in Table 2 These 10 or 11 layers represented the first antireflection coating with a filter effect for blue light. During the application 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 hardcoat was a TiO.sub.2 layer. The respectively applied layer thickness of the TiO.sub.2 layer and SiO.sub.2 layer is specified in [nm] in Table 2 and Table 3, respectively. The transmission at 464 nm and the transmission at 450 nm, the luminous reflectance and the corresponding yellow value G and the full width at half maximum are also given in Table 2 and Table 3, respectively. The following abbreviations are used in Tables 2 and 3: t/nm: Layer thickness in [nm] T (464 nm): Transmission at 464 nm T (450 nm): Transmission at 450 nm Lum R: Luminous reflectance FWHM: Full width at half maximum.

(20) TABLE-US-00003 TABLE 2 Antireflection coating with filter effect for blue light with a reflection maximum at 464 nm Example 1 Example 2 Example 3 Example 4 T (464 nm) 82% 88% 88% 92% Yellow value G 12 9 9 6 Lum R in % 2.3 1.7 1.7 1.4 FWHM in nm 48 48 48 45 t/nm t/nm t/nm t/nm Hardcoat 3000 3000 3000 3000 TiO.sub.2 25 21 21 21 SiO.sub.2 26 26 26 25 TiO.sub.2 135 135 135 137 SiO.sub.2 18 18 18 25 TiO.sub.2 35 35 35 29 SiO.sub.2 57 57 57 57 TiO.sub.2 27 27 27 27 SiO.sub.2 34 34 34 32 TiO.sub.2 114 114 114 114 SiO.sub.2 80 80 90 80 TiO.sub.2 5 4 — 4 Top coat 5 5 5 5

(21) TABLE-US-00004 TABLE 3 Antireflection coating with filter effect for blue light with a reflection maximum at 450 nm Example 5 T (450 nm) 83% Yellow value G 11 Lum R in % 1.1 FWHM in nm 40 t/nm t/nm Hardcoat 3000 TiO.sub.2 22 SiO.sub.2 21 TiO.sub.2 124 SiO.sub.2 25 TiO.sub.2 30 SiO.sub.2 59 TiO.sub.2 24 SiO.sub.2 30 TiO.sub.2 109 SiO.sub.2 92 TiO.sub.2 — Top coat 5

(22) Application of the antireflection coating without a filter effect for blue light

(23) Following the application of the antireflection coating with filter effect for blue light on the front surface of the finished spectacle lens which had been provided with a hardcoat, the spectacle lens was turned in the coating system, for the purposes of coating the back surface with a conventional antireflection coating without a filter effect for blue light. Such a conventional coating is known, for example, from U.S. 2017/0219848 A1 (see Table 3 and the associated description), the content of which is hereby incorporated by reference.

(24) The coating was carried out analogously to the application of the antireflection coating with a filter effect for blue light. An adhesion layer of Cr/SiO.sub.2 was vapor deposited between the hardcoat layer and the antireflection coating. The layer thicknesses applied in each case and the respective coating materials are specified in Table 4.

(25) TABLE-US-00005 TABLE 4 Antireflection coating without a filter effect for blue light Example 6 t/nm Hardcoat 3000 Adhesion layer (Cr/SiO.sub.2) 0.6 Al.sub.2O.sub.3 20.0 SiO.sub.2/Al.sub.2O.sub.3 170.0 TiO.sub.2 15.0 SiO.sub.2/Al.sub.2O.sub.3 47.0 ITO 3.0 TiO.sub.2 29.8 SiO.sub.2/Al.sub.2O.sub.3 114.0 Top coat 5.0 t/nm: Thickness in [nm] ITO: Indium tin oxide

(26) Application of a Top Coat

(27) A protective layer that is both hydrophobic and oleophobic was applied to the first and second antireflection layers as the outermost layer (top coat). This top coat is dirt-repellent and makes cleaning the spectacle lens easier.

(28) A 5 nm thick layer of Duralon.sup.UltraTec (Cotec GmbH, 63791 Karlstein a. Main, Germany) was applied to the first surface of the spectacle lens in the PVD system. The Duralon.sup.UltraTec was arranged in the PVD system according to the manufacturer's instructions and heated in vacuo with evaporation, so that it subsequently precipitates on the surface of the spectacle lens. The spectacle lens was then turned, and the second surface of the spectacle lens was likewise covered with a 5 nm thick layer of Duralon.sup.UltraTec.

(29) The respective layer thickness was set via the duration of vapor deposition, in accordance with manufacturer details relating to the coating unit. The respective layer thickness here was determined using a quartz crystal oscillator system (XTC Controller, Inficon, CH-7310 Bad Ragaz, Switzerland) which measures the change in the frequency of an electrical crystal oscillator, the frequency changing with the layer thickness of the respective growing antireflection coating. The crystal oscillator is also coated during the coating procedure, in an analogous way, and the change in frequency is measured at the same time.

(30) A measurement was carried out to check the applied antireflection coating with a filter effect for blue light: 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 finished spectacle lens 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.

(31) The layer thicknesses applied in each case were calculated using the OptiLayer software program, version 12.37, from OptiLayer GmbH. A target reflection curve was input initially for the calculation. The software program possessed algorithms which calculate the layer structure of an antireflection coating, 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, and the use of TiO.sub.2 and SiO.sub.2 as layer materials. The calculations of Examples 1 to 4 were based on the following refractive indices n at the wavelength of the reflection maximum of 464 nm: TiO.sub.2: n=2.52, SiO.sub.2: n=1.47, top coat: n=1.38, hardcoat: n=1.61 and substrate: n=1.605. The calculation of Example 5 was based on the following refractive indices n at the wavelength of the reflection maximum of 450 nm: TiO.sub.2: n=2.54, SiO.sub.2: n=1.475, top coat: n=1.38, hardcoat: n=1.62 and substrate: n=1.63. The imaginary part k is k=0 for all materials. The maximum number of layers was restricted to 10 and 11, respectively. 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.

(32) 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.

(33) 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.

(34) 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.