Ophthalmic lens

Abstract

A thin film coating for an ophthalmic lens is provided, that comprises alternating layers of high and low index materials. The coating attenuates the transmission of light and has a spectral reflectance curve characterized by a reflectance of at least about 90% in a range from 320 nm to 420 nm, by 50% at 440 nm, by 5% or less at 460 nm, and wherein the spectral reflectance curve is monotonically or strictly decreasing between 420 nm to 460 nm.

Claims

1. An ophthalmic lens comprising: an optical lens having a front surface and a back surface; a coating on the front surface that attenuates transmission of light with a spectral reflectance curve that is monotonically decreasing from 90% or more to 10% or less, within the range from 420 nm to 460 nm.

2. The ophthalmic lens of claim 1, wherein the spectral reflectance curve is strictly decreasing from 90% or more to 10% or less, within the range from 420 nm to 460 nm.

3. The ophthalmic lens of claim 1, wherein the spectral reflectance curve at 50% reflectance within the range from 420 nm to 460 nm, has a slope m of between about −0.7 to about −0.62.

4. The ophthalmic lens of claim 1, wherein the spectral reflectance curve at 440 nm has a slope m of between about −0.7 to about −0.62.

5. The ophthalmic lens of claim 1, wherein the spectral reflectance curve is monotonically decreasing from 90% or more to 5% or less, within the range from 420 nm to 460 nm.

6. The ophthalmic lens of claim 1, wherein the spectral reflectance curve is monotonically decreasing from 95% or more to 5% or less, within the range from 420 nm to 460 nm.

7. The ophthalmic lens of claim 1, wherein the spectral reflectance curve is less than 20% from 460 nm to 700 nm.

8. The ophthalmic lens of claim 1, wherein the spectral reflectance curve is less than 15% from 460 nm to 700 nm.

9. The ophthalmic lens of claim 1, wherein the spectral reflectance curve further comprises a secondary peak of reflectance of at least 5%, within the range from 460 nm to 540 nm.

10. The ophthalmic lens of claim 9, wherein the secondary peak of reflectance is at about 490 nm.

11. The ophthalmic lens of claim 9, wherein the secondary peak of reflectance is between 5% to 15%.

12. The ophthalmic lens of claim 9, wherein the secondary peak of reflectance has a full width half maximum of about 55 nm.

13. The ophthalmic lens of claim 9, wherein the spectral reflectance curve is strictly decreasing from 90% or more to 10% or less, within the range from 420 nm to 460 nm.

14. The ophthalmic lens of claim 9, wherein the spectral reflectance curve at 50% reflectance between 400 nm to 450 nm has a slope m of between about −0.7 to about −0.62.

15. The ophthalmic lens of claim 9, wherein the spectral reflectance curve at 440 nm has a slope m of between about −0.7 to about −0.62.

16. The ophthalmic lens of claim 9, wherein the spectral reflectance curve is monotonically decreasing from 90% or more to 5% or less, within the range from 420 nm to 460 nm.

17. The ophthalmic lens of claim 9, wherein the spectral reflectance curve is monotonically decreasing from 95% or more to 5% or less, within the range from 420 nm to 460 nm.

18. An ophthalmic lens comprising: an optical lens having a front surface and a back surface; a coating on the front surface that attenuates transmission of light with a spectral reflectance curve that is monotonically decreasing from 80% or more to 10% or less, within the range from 420 nm to 460 nm.

19. The ophthalmic lens of claim 18, wherein the spectral reflectance curve is strictly decreasing from 80% or more to 10% or less, within the range from 420 nm to 460 nm.

20. The ophthalmic lens of claim 18, wherein the spectral reflectance curve further comprises a secondary peak of reflectance of at least 5%, within the range from 460 nm to 540 nm.

21. The ophthalmic lens of claim 20, wherein the secondary peak of reflectance is between 5% to 15%.

22. The ophthalmic lens of claim 21, wherein the secondary peak of reflectance has a full width half maximum of about 55 nm.

23. The ophthalmic lens of claim 20, wherein the secondary peak of reflectance is at about 490 nm.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The embodiments described herein and other features, advantages, and disclosures contained herein, and the manner of attaining them, will be better understood from the following description in conjunction with the accompanying drawing figures, in which like reference numerals identify like elements, and wherein:

(2) FIG. 1 is a vertical section view of an eye, showing the refraction of different wavelengths of light;

(3) FIG. 2 is an exploded section view of an ophthalmic lens system;

(4) FIG. 3 is a data plot of the reflectance and wavelength of an ophthalmic lens system;

(5) FIG. 4 is a data plot of the reflectance and wavelength of an alternative embodiment of an ophthalmic lens system;

(6) FIG. 5 is a data plot of the reflectance and wavelength of another embodiment of an ophthalmic lens system;

(7) FIG. 6 is a data plot of the reflectance and wavelength of yet another embodiment of an ophthalmic lens system.

DETAILED DESCRIPTION

(8) In the following detailed description of embodiments of the present disclosure, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, such specific embodiments. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present disclosure.

(9) Reference is now made to FIG. 2, which illustrates an ophthalmic lens system 10, that comprises an optical lens 12 having a (object side) front surface 14 and a (eye side) back surface 16. Optical lenses used in ophthalmic systems are typically produced with a convex front surface 14 and concave back surface 16. A thin film coating 18 that attenuates transmission of HEV light is applied to front surface 14. An optional anti-reflective thin film coating 22 may be applied to back surface 16.

(10) It has been found that the attenuation of HEV light in a range of wavelengths centered at about 440 nm reduces the problem of glare and blue blur caused by HEV light, without significantly affecting the portion of the spectrum that is important for the circadian response. In one embodiment, thin film coating 18 attenuates light in a range of about 420 nm to about 460 nm, which reduces the transmission of HEV light while avoiding significant interference with the circadian response. In a further embodiment, the transmission of light is attenuated by at least about 90% at about 420 nm and decreases to about 5% or less at about 460 nm. Within this range, the transmission of light is preferably attenuated between about 45% to about 55% at a wavelength of about 440 nm, and more preferably by about 50% at a wavelength of about 440 nm.

(11) It is desirable that the attenuation of light decreases rapidly above about 440 nm, to minimize interference with the circadian response after blocking unwanted HEV and UV wavelengths. Thus, in a preferred embodiment, the attenuation of HEV light between about 420 nm and about 460 nm has a curve that is monotonically decreasing—i.e. is either decreasing or nonincreasing over the range from 420 nm to 460 nm. More preferably, the attenuation of HEV light between about 420 nm and about 460 nm has a curve that is strictly decreasing—i.e. is continuously decreasing without a plateau. In a particularly preferred embodiment, the attenuation of light comprises a spectral reflectance curve that is strictly decreasing between about 420 nm and about 460 nm, and has a slope of about −0.70 at about 440 nm.

(12) Thin film coating 18 may also assist in blocking transmission of UV light by attenuating light in a range of wavelengths less than about 420 nm. In one embodiment, thin film coating 18 may further attenuate light by about 90% or more in a region from about 320 nm to about 420 nm. The attenuation of visible light above about 460 nm is ideally minimized. In a further embodiment, the attenuation of light in a range of about 460 nm to about 700 nm is attenuated by about 20% or less, and more preferably by about 15% or less.

(13) Thin film coatings that are designed to attenuate light below about 460 nm may give the ophthalmic lens system an undesirable purple or dark blue reflection. It has been found that this effect may be reduced by the attenuation of transmitted light in a secondary region that comprises a peak of attenuation between about 5 to 15%, at a wavelength between about 480 nm to about 490 nm. In one embodiment, the secondary region comprises a peak of attenuation between about 5% to about 15%, at about 490 nm, with a full width at half maximum (FWHM) of about 55 nm. In a preferred embodiment, the secondary region has a peak of attenuation of about 12%. Less than 5% attenuation does not significantly reduce the purple or dark blue reflectance.

(14) Thin film coating 18 comprises multiple layers of alternating high and low index materials, such as metal oxides, metal fluorides and other materials known in the art. High index materials have an index of refraction greater than about 1.90, and include, but are not limited to: TiO.sub.2, ZrO.sub.2, HfO.sub.2, and commercially available materials such as Dralo (Umicore Thin Film Products—Providence, R.I.). The low index materials have an index of refraction of less than about 1.8 and include but are not limited to: SiO.sub.2, MgF.sub.2, Al.sub.2O.sub.3. In a preferred embodiment, the low index material has an index of refraction of about 1.50 or less. Other fluorides and carbides are known in the art to have suitable refractive indices for use in thin film coating 18, such as CeF.sub.3, cryolite (Na.sub.3AlF.sub.6), and AlF.

(15) The number of layers and the thickness of the high and low index materials in each layer determine the characteristics of the attenuation of transmission of light and spectral reflectance curve of the thin film coating. In one embodiment, thin film coating 18 comprises at least eight layers of alternating high and low index materials, and preferably comprises ten layers. In a particularly preferred embodiment, thin film coating comprises ten layers of alternating high and low index materials, and most preferably ten layers of alternating TiO.sub.2 and SiO.sub.2. Although more than ten alternating layers are possible, the benefits provided by the additional layers may be outweighed by the increased manufacturing time.

(16) The layers of alternating high and low index materials that comprise thin film coating 18 may be applied to the front surface 14 of the substrate optical lens 12 by various methods known in the art, including chemical vapor deposition, and physical vapor deposition such as sputtering and electron beam evaporation. In one embodiment, high index layers of TiO.sub.2 may be applied by vapor deposition of a Ti.sub.3O.sub.5 starting material, as is known in the art.

(17) Optical lens 12 may be formed of a variety of different plastic materials that are known in the art. In one embodiment, the lens material is a high refractive index material such as a urethane-based polymer. In a preferred embodiment, the lens material does not significantly attenuate the transmission of light. Conventional UV/blue blocking lenses involve dyes that can give the lens an undesirable yellowish to red tint. These conventional lenses may also generally reduce the transmission of light across a large portion of the visible spectrum, thereby reducing their effectiveness to daytime wear only. In contrast, the attenuation and light transmission curve of the ophthalmic lens system may be substantially determined by thin film coating 18, which allows optical lens 12 to be colorless. By eliminating the need for the dyes, the color acuity and total amount of light entering the eye are improved.

(18) Nonetheless, optical lens 12 may contain in-mass dyes or other additives. In one embodiment, optical lens 12 may contain a dye or pigment that gives the lens an aesthetically desirable tint or coloring. In another embodiment, optical lens 12 may contain an in-mass, UV absorbing additive that supplements the UV blocking properties of thin film coating 18. UV/blue absorbing dyes and additives are commercially available, and include BPI Melanin Therapeutic Tint, Diamond Dye 550, UV Blue Filter Vision 450 (Brain Power Inc.—Miami, Fla.), and C200-95 Opti-Safe Lens Dye (Phantom Research Laboratories Inc.—Miami, Fla.). Other UV absorbing additives known in the art include polyamides, benzophenones, hydroxybenzophenone, hydroxyphenylbenzotriazole, benzotriazoles, hydroxyphenyltriazines, 2-(2-hydroxyphenyl)-benzotriazoles, 2-hydroxy-benzophenones, hydroxyphenyl-s-triazines, and oxalanilides. In a preferred embodiment, the UV absorbing additive attenuates the transmission of light by at least about 95% in a wavelength range from about 280 nm to about 400 nm and more preferably, attenuates transmission by at least 99% in a range from about 320 nm to about 400 nm. The addition of a UV absorbing additive may give optical lens 12 a pronounced yellow to red tint.

(19) Ophthalmic lens system 10 optionally includes, but does not require an anti-reflective coating 22 applied to back surface 16 of optical lens 12. Anti-reflective coating 22 reduces the unwanted reflection of UV and HEV light from back surface 16 back toward the wearer's eye. In one embodiment, anti-reflective coating 22 has a transmission of at least about 99.25% in the range of wavelengths from about 280 nm to about 700 nm. In a preferred embodiment, anti-reflective coating 22 reflects less than about 1.5% of light in a range from about 300 nm to about 460 nm. Such anti-reflective coatings and methods of applying them to optical lenses are well known in the art.

(20) The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the scope of the invention.

Example 1

(21) A thin film coating comprising ten layers of alternating high index (TiO.sub.2) and low index (SiO.sub.2) materials was developed as shown in Table 1. Layer 1 represents the layer positioned closest to optical lens 12, with TiO.sub.2 being the first, innermost material in the thin film coating. Layer 10 represents the layer positioned farthest from optical lens 12, with SiO.sub.2 being the last, outermost material in the thin film coating. The thickness of the materials in each layer is shown in Table 1.

(22) TABLE-US-00001 TABLE 1 Example 1, Thin Film Coating Composition Layer Material Thickness (nm) 10 SiO.sub.2 144.763 9 TiO.sub.2 37.592 8 SiO.sub.2 52.338 7 TiO.sub.2 37.006 6 SiO.sub.2 61.246 5 TiO.sub.2 33.492 4 SiO.sub.2 60.671 3 TiO.sub.2 39.996 2 SiO.sub.2 59.378 1 TiO.sub.2 25.230

(23) The spectral reflectance curve of the thin film coating at wavelengths ranging from 300 nm to 700 nm is shown in FIG. 3. The attenuation of transmission is characterized by a primary reflection region having a spectral reflectance curve 30 with about 50% reflectance at about 440 nm and a slope of about m=−0.7. Reflectance is at least about 90% from about 320 nm to about 420 nm, at least about 95% at about 400 nm, is strictly decreasing from about 90% at 420 nm to about 5% or less at 460 nm, and is about 20% or less from about 460 nm to about 700 nm. A secondary reflection region 32 is present having a peak of reflectance of about 15% at about 490 nm, with an FWHM of about 55. Reflectance decreases on either side of the peak to about 2% or less at 460 nm and 540 nm. The secondary reflection region reduces the purple or dark blue reflection discussed above and provides some attenuation of HEV light in the range of about 480 nm to about 490 nm, while providing sufficient transmission of light above 460 nm to avoid impairment of the circadian response.

(24) As shown in FIG. 3, attenuation of transmission decreases at wavelengths less than about 320 nm. As discussed above, the UV blocking characteristics of ophthalmic lens system 10 may be supplemented by adding an in-mass UV absorbing additive to optical lens 12, such that attenuation of transmission is at least about 95% from about 320 nm to about 400 nm.

Example 2

(25) A thin film coating comprising ten layers of alternating high index (TiO.sub.2) and low index (SiO.sub.2) materials was developed as described in Example 1, except that the thickness of the materials in each layer was as shown in Table 2.

(26) TABLE-US-00002 TABLE 2 Example 2, Thin Film Coating Composition Layer Material Thickness (nm) 10 SiO.sub.2 144.402 9 TiO.sub.2 37.567 8 SiO.sub.2 50.631 7 TiO.sub.2 37.296 6 SiO.sub.2 63.374 5 TiO.sub.2 33.333 4 SiO.sub.2 61.332 3 TiO.sub.2 39.166 2 SiO.sub.2 59.017 1 TiO.sub.2 23.452

(27) The spectral reflectance curve of the thin film coating at wavelengths ranging from 300 nm to 700 nm is shown in FIG. 4. The attenuation of transmission is characterized by a primary reflection region similar to the thin film coating of Example 1, and having a spectral reflectance curve 40 with about 50% reflectance at about 440 nm and a slope of about m=−0.65. A secondary reflection region 42 is present having a peak of reflectance of about 10% at about 490 nm, with an FWHM of about 53. Reflectance decreases on either side of the peak to a reflectance of about 2% or less at 460 nm and 540 nm.

Example 3

(28) A thin film coating comprising ten layers of alternating high index (TiO.sub.2) and low index (SiO.sub.2) materials was developed as described in Example 1, except that the thickness of the materials in each layer was as shown in Table 3.

(29) TABLE-US-00003 TABLE 3 Example 3, Thin Film Coating Composition Layer Material Thickness (nm) 10 SiO.sub.2 141.462 9 TiO.sub.2 37.806 8 SiO.sub.2 50.204 7 TiO.sub.2 37.324 6 SiO.sub.2 66.067 5 TiO.sub.2 33.582 4 SiO.sub.2 61.666 3 TiO.sub.2 36.906 2 SiO.sub.2 58.956 1 TiO.sub.2 21.624

(30) The spectral reflectance curve of the thin film coating at wavelengths ranging from 300 nm to 700 nm is shown in FIG. 5. The attenuation of transmission is characterized by a primary reflection region similar to the thin film coating of Example 1, and having a spectral reflectance curve 50 with about 50% reflectance at about 440 nm and a slope of about m=−0.62. A secondary reflection region 52 is present having a peak attenuation of about 5% at about 490 nm, with an FWHM of about 56. Reflectance decreases on either side of the peak to about 2% or less at 460 nm and 540 nm.

Example 4

(31) It is also possible to develop thin film coatings having characteristics that resemble the attenuation of transmission in conventional UV/blue blocking lenses, without the need for in-mass dyes or pigments. A thin film coating comprising ten layers of alternating high index (TiO.sub.2) and low index (SiO.sub.2) materials was developed as described in Example 1, except that the thickness of the materials in each layer was as shown in Table 4.

(32) TABLE-US-00004 TABLE 4 Example 4, Thin Film Coating Composition Layer Material Thickness (nm) 10 SiO.sub.2 153.449 9 TiO.sub.2 39.878 8 SiO.sub.2 55.478 7 TiO.sub.2 39.227 6 SiO.sub.2 64.921 5 TiO.sub.2 35.501 4 SiO.sub.2 64.311 3 TiO.sub.2 42.396 2 SiO.sub.2 62.941 1 TiO.sub.2 26.743

(33) The spectral reflectance curve of the thin film coating at wavelengths ranging from 300 nm to 700 nm is shown in FIG. 6. The attenuation of transmission is characterized by a primary reflection region similar to the thin film coating of Example 1, except shifted toward higher wavelengths—i.e. having a spectral reflectance curve 60 with about 50% reflectance at about 460 nm and a slope of about m=−0.70. Reflectance is at least about 90% from about 340 nm to about 440 nm, at least about 95% at about 420 nm, is strictly decreasing from about 90% at 440 nm to about 5% or less at 480 nm, and is about 20% or less from about 480 nm to about 700 nm. A secondary reflection region 62 is present having a peak of reflectance of about 15% at about 510 nm, with an FWHM of about 56. Reflectance decreases on either side of the peak to about 2% or less at 480 nm and 560 nm. Thus, the primary reflection region attenuates transmission of a wider range of HEV light, but overlaps significantly with the range of from about 460 nm to about 500 nm which is believed to be important for the circadian response.

(34) The ophthalmic lens system 10 in accordance with the embodiments described herein provides attenuation of damaging and fatigue-inducing UV and HEV light. The thin film coating 18 particularly minimizes transmission of the portions of HEV light that cause glare and blue light blur such that visual acuity is improved in viewing computer and electronic device displays, and under modern lighting conditions such as fluorescent and LED lamps. Meanwhile, the ophthalmic lens system 10 allow significant transmission of light in the wavelength range associated with the circadian cycle of the body to reach the eye.

(35) Although thin film coating 18 is described as applied to the front surface of an ophthalmic lens system 10, those of skill in the art will appreciate that thin film coating 18 may also be applied to the back surface of an ophthalmic lens system. In addition, other types of coatings known in the art may be incorporated into thin film coating 18. For example, thin film coating 18 may also incorporate an anti-static coating, a scratch resistant coating, a hydrophobic/oleophobic coating and/or an anti-reflective coating as are known in the art.

(36) While particular embodiments of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the present disclosure. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this disclosure.