Contact lenses containing diffractive optical elements and related methods

Abstract

The present disclosure relates to a contact lens (100) comprising a diffractive optical element (101), a filter (103), and an optical axis (109) traveling through the filter and the diffractive optical element. The diffractive optical element (101) is configured to focus visible light. The light filter (103) is configured to filter out light having a wavelength of 450 nm to 495 nm. The light filter (103) may allow light having a wavelength of from 500 nm to 750 nm to pass through. The light filter (103) may include one or more colorants. The present disclosure also relates to a method (600) of manufacturing a contact lens. The disclosure also relates to a method (700) of correcting vision of a user.

Description

Technical Field

[0001] The present disclosure relates to contact lenses. More particularly, but not exclusively, the present disclosure relates to a contact lens comprising a diffractive optical element configured to focus visible light and a filter configured to filter out light having a wavelength of 450 nm to 495 nm. Background Art

[0002] Ophthalmic glasses that use refraction to focus visible light onto the user's retina are well known.Instead of or in addition to using refraction, diffractive optical elements are used to focus light.

[0003] Diffractive optical elements interact with light by diffracting light at an interface between two or more materials that each have a different refractive index from one another.Some diffractive optical elements have a diffractive structure made of annular zones arranged to focus incident light to one or more focal points.

[0004] Eyeglasses containing diffractive optical elements will have much greater chromatic aberration than a refractive lens of the same diffractive power. The focal power (in diffractive power) of a diffractive optical element varies in direct proportion to the wavelength. The focal power is the inverse of the focal length, so the distance of the focused light from the eyeglasses is inversely proportional to the wavelength. This means that for a given annular zone of a diffractive optical element, light with a shorter wavelength will be focused further away from the eyeglasses than light with a longer wavelength. This relationship gives rise to longitudinal chromatic aberration. In use, chromatic aberration will cause a user of an ophthalmic eyeglass containing a diffractive optical element to experience a multi-colored, blurred halo around the image. This reduces the quality of vision for the user.

[0005] The present disclosure seeks to alleviate the above mentioned problems.Alternatively or additionally, the present disclosure seeks to provide improved contact lenses comprising diffractive optical elements. Summary of the invention

[0006] A first aspect of the present disclosure relates to a contact lens comprising a diffractive optical element, a filter, and an optical axis that passes through the filter and the diffractive optical element, wherein: the diffractive optical element is configured to focus visible light, and the filter is configured to filter out light having a wavelength of 450nm to 495nm.

[0007] A second aspect of the present disclosure relates to a method of manufacturing a contact lens, comprising: obtaining one or more colorants that absorb light having a wavelength of 450nm to 495nm and allow light having a wavelength of 500nm to 750nm to travel through; forming a diffractive optical element having a diffractive structure configured to focus visible light having a wavelength greater than 495nm; and forming a contact lens incorporating the diffractive optical element and the one or more colorants.

[0008] A third aspect of the present disclosure relates to a method for correcting a user's vision, comprising: obtaining a contact lens according to the present disclosure; placing the contact lens on the surface of the user's eye; and causing the contact lens to diffract light so that the light is focused on the retina of the user's eye.

[0009] Preferred but optional features of the present disclosure are set out below and in the accompanying claims.

[0010] Of course, it should be understood that features described in relation to one aspect of the present disclosure may be incorporated into other aspects of the present disclosure. For example, the method of the present disclosure may be incorporated into any of the features described with reference to the apparatus of the present disclosure and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Example embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings.

[0012] Figure 1 is a front view of a contact lens according to a first embodiment;

[0013] Figure 2 yes Figure 1 A transverse cross section of a contact lens;

[0014] Figure 3 A representation showing light traveling through a prior art contact lens;

[0015] Figure 4 Showing light traveling through Figure 1 and Figure 2 Representation of contact lenses;

[0016] Figure 5 showing a side cross-sectional view of a contact lens according to another embodiment;

[0017] Figure 6 showing a side cross-sectional view of a contact lens according to another embodiment;

[0018] Figure 7 is a flow chart of steps of a method for manufacturing a contact lens according to another embodiment; and

[0019] Figure 8 is a flow chart of steps of a method of correcting a user's vision according to another embodiment. DETAILED DESCRIPTION

[0020] According to a first aspect of the present disclosure, a contact lens includes a diffractive optical element, an optical filter, and an optical axis that passes through the optical filter and the diffractive optical element. The diffractive optical element is configured to focus visible light. The optical filter is configured to filter out light having a wavelength of 450 nm to 495 nm.

[0021] As used herein, the term "contact lens" is commonly used in the art to refer to an ophthalmic lens that can be placed on a person's eye. It should be understood that such a contact lens will provide clinically acceptable on-eye movement and will not be bonded to a person's (two) eyes.

[0022] The contact lens has a single diffractive optical element.

[0023] Contact lenses may be used to correct or improve vision associated with myopia, presbyopia, hyperopia, astigmatism, or another refractive error.

[0024] The filter may allow light having a wavelength of 500nm to 750nm to pass through or transmit light having a wavelength of 500nm to 750nm. The filter may allow light having a wavelength of 496nm to 750nm to pass through. The filter may allow light having a wavelength greater than 500nm to pass through. The filter may allow light having a wavelength greater than 495nm to pass through.

[0025] The filter may include one or more colorants. One or more of the colorants may be a dye. One or more of the colorants may be a pigment. One or more of the colorants may be a polymerizable dye. One or more of the colorants may be an anthraquinone dye. One or more of the colorants may be configured to filter out light having a wavelength of 450nm to 495nm. One or more of the colorants may be configured to filter out light having a wavelength of 400nm to 495nm. A combination of two or more colorants may be configured to filter out light having a wavelength of 400nm to 495nm. A combination of two or more colorants may be configured to filter out light having a wavelength of 450nm to 495nm.

[0026] The filter may comprise one or more compounds. One or more of the compounds may be configured to filter out UV light. One or more of the compounds may be configured to filter out light that is harmful to the human eye. One or more of the compounds may absorb light having a wavelength of 100nm to 400nm. One or more of the compounds may absorb light having a wavelength of 400nm to 450nm. One or more of the compounds may absorb light having a wavelength of 100nm to 450nm. One or more of the compounds may absorb light having a wavelength of 100nm to 495nm. A combination of two or more compounds may be configured to filter out light having a wavelength of 100nm to 495nm. The filter may absorb wavelengths that may be harmful to the human eye. The filter may comprise at least one compound that absorbs UV light. A skilled person will know suitable UV blocking compounds. The UV blocking compound may be colorless.

[0027] The contact lens may include a material having one or more colorants dispersed therein. The contact lens may include a material having one or more colorants and one or more compounds dispersed therein. The contact lens may include a polymer material. The contact lens may include a polymer material having one or more colorants dispersed therein. The contact lens may include a polymer material having one or more colorants and one or more compounds dispersed therein. One or more of the colorants may be a polymerizable dye. The contact lens may include a polymer matrix formed from one or more monomers and one or more colorants.

[0028] The filter may include a first colorant having an absorption maximum wavelength in the range of 450 nm to 495 nm and a second colorant having an absorption maximum wavelength in the range of 450 nm to 495 nm. The first colorant may have a different absorption maximum wavelength compared to the second colorant.

[0029] As used herein, the term "absorption maximum wavelength" is defined as the wavelength at which the colorant has the highest absorbance as measured in the UV-Visible spectrum. This is also referred to as the characteristic wavelength of the colorant.

[0030] The characteristic wavelength of the diffractive optical element may be from 500 nm to 750 nm.The characteristic wavelength of the diffractive optical element is defined as the wavelength at which the diffractive optical element is designed to have a predetermined focal length.

[0031] The optical axis of the glasses is defined with reference to a far point light source. Light from a far point light source on the optical axis of the glasses (hereinafter referred to as an on-axis far point light source) will be focused onto the optical axis of the glasses.

[0032] The optical zone is centered on the optical axis. The optical axis may be aligned with the center of the contact lens. The optical zone consists of the portion of the contact lens that is optically functional in use. The optical zone may be configured to be positioned above or in front of the pupil of the eye when in use. In a plan view, the contact lens may have an optical zone surrounded by a peripheral zone. The peripheral zone is not part of the optical zone, but is located outside the optical zone. When the contact lens is worn, the peripheral zone may be located above the iris. The peripheral zone may provide a mechanical function, for example, increasing the size of the contact lens, thereby making the contact lens easier to handle. The peripheral zone may extend to the edge of the contact lens. The peripheral zone may provide ballast to prevent the contact lens from rotating and / or provide a shaping area that improves the comfort of the contact lens wearer.

[0033] The contact lens may have a circular shape. The contact lens may have an oval shape. The contact lens may have an elliptical shape. The contact lens may have a diameter of 10 mm to 20 mm. The contact lens may have an optical zone having a diameter of 7 mm to 10 mm. The contact lens may have a convex front surface. The contact lens may have a concave rear surface. The shape of the optical zone may be circular. The shape of the optical zone may be oval. The shape of the optical zone may be elliptical.

[0034] The diffractive optical element may be centered on the optical axis of the contact lens. In plan view, the diffractive optical element may be surrounded by a peripheral region of the contact lens. The diffractive optical element may be positioned within an optical zone of the contact lens. The diffractive optical element may define an optical zone of the contact lens.

[0035] In a transverse cross section containing the optical axis, the diffractive optical element may comprise a series of peaks and valleys having a first refractive index filled by a material having a second refractive index.The diffractive optical element may comprise two or more materials each having a different refractive index relative to each other.

[0036] The diffractive optical element may include a first portion having a first refractive index and a second portion including a liquid crystal cell switchable between a matched state and a mismatched state. In the matched state, the refractive index of the liquid crystal cell may be equal to the first refractive index. In the mismatched state, the refractive index of the liquid crystal cell may be different from the first refractive index. In the mismatched state, the refractive index of the liquid crystal cell may be greater than the refractive index of the liquid crystal cell in the matched state. In the mismatched state, the refractive index of the liquid crystal cell may be less than the refractive index of the liquid crystal cell in the matched state. The liquid crystal cell may be electrically switchable.

[0037] In a transverse cross section running through the optical axis, a first portion of the diffractive optical element may comprise a series of peaks and troughs. The peaks and troughs of the first portion may abut the liquid crystal cells of the second portion. The liquid crystal may switch between a matching state in which its refractive index is equal to a first refractive index of the first portion and a non-matching state in which its refractive index is different from the first refractive index of the first portion.

[0038] In a transverse cross section containing the optical axis, the diffractive optical element may include a series of peaks and valleys on its front surface surrounded by the material of the contact lens. The material of the contact lens may have a different refractive index compared to the refractive index of the diffractive optical element. The boundary between the diffractive optical element and the material of the contact lens may define the diffractive structure of the diffractive optical element.

[0039] The diffractive optical element may have a radial variation of the refractive index, i.e., the refractive index may vary radially outward from the optical axis. The diffractive optical element may have an axial variation of the refractive index, i.e., the refractive index may vary in the direction of the optical axis. The diffractive optical element may have a refractive index that varies sinusoidally in the axial direction. The diffractive optical element may have a refractive index that varies sinusoidally in the radial direction. The diffractive optical element may have a refractive index that varies linearly in the radial direction. The diffractive optical element may have a refractive index that varies linearly in the axial direction. The diffractive optical element may have a radially increasing refractive index. The diffractive optical element may have a radially decreasing refractive index. The diffractive optical element may have an axially increasing refractive index. The diffractive optical element may have an axially decreasing refractive index. The refractive index of the diffractive optical element may be uniform.

[0040] In plan view, the diffractive optical element may include concentric annular regions. The concentric annular regions may be centered around the optical axis of the contact lens. Each pair of peaks may define an annular region. Each concentric annular region may define an annular diffractive zone.

[0041] The diffractive optical element may be embedded in a contact lens. The contact lens may include a lens body. The diffractive optical element may be embedded in the lens body. The diffractive optical element may have a refractive index different from the refractive index of the lens body. The refractive index of the lens body may be uniform. For example, a first portion of the diffractive optical element may have a refractive index of 1.48, and a second portion of the diffractive optical element may be a liquid crystal cell that can switch between a refractive index of 1.48 and 1.7.

[0042] The diffractive optical element may include a diffractive structure that diffracts and refracts light incident thereon.

[0043] The contact lens may include a layer containing an optical filter. The layer may form the front surface of the contact lens. The layer may form the back surface of the contact lens. The contact lens may further include a lens body bonded to the layer containing the optical filter. The layer may have a thickness that is less than the thickness of the lens body. The layer may cover the entire front surface of the lens body. The layer may cover the entire back surface of the lens body. The layer may cover a portion of the front surface of the lens body. The layer may cover a portion of the back surface of the lens body. The layer may cover a central portion of the front or back surface of the lens body, for example, a portion located in front of a diffractive optical element such that light must travel through the layer in order to be diffracted by the diffractive optical element. There may be a peripheral area of ​​the contact lens that is not covered by the layer.

[0044] The contact lens may be a soft contact lens. The contact lens may include a silicone hydrogel material. The contact lens may be a hard gas permeable contact lens. The contact lens may be a toric contact lens. For example, the toric contact lens may include an optical zone that is shaped to correct a person's astigmatism. The contact lens may be a daily disposable lens. The contact lens may be an extended wear contact lens.

[0045] The contact lens may include an elastomeric material, a silicone elastomeric material, a hydrogel material, or a silicone hydrogel material, or a combination thereof. As understood in the field of contact lenses, a hydrogel is a material that keeps water in a state of equilibrium and is free of silicone-containing chemicals. A silicone hydrogel is a hydrogel containing silicone-containing chemicals. As described in the background of the present disclosure, the hydrogel material and the silicone hydrogel material have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, the hydrogel material and the silicone hydrogel material have an EWC of from about 30% to about 70% (wt / wt). In contrast, as described in the background of the present disclosure, the silicone elastomeric material has a water content of from about 0% to less than 10% (wt / wt). Generally speaking, the silicone elastomeric material used with the present method or apparatus has a water content of from 0.1% to 3% (wt / wt). Examples of suitable lens formulations include lens formulations with the following United States Adopted Names (USAN): methafilcon A, ocufilcon A, ocufilcon B, ocufilcon C, ocufilcon D, omafilcon A, omafilcon B, comfilcon A, enfilcon A, stenfilcon A, fanfilcon A, etafilcon A, senofilcon A, senofilcon B, senofilcon C, seno ... C, senofilcon D, senofilcon A, senofilcon B, senofilcon C, senofilcon C, senofilcon D, senofilcon A, senofilcon B, senofilcon C, senofilcon C, senofilcon C, senofilcon D, senofilcon A, senofilcon B, senofilcon C, senofilcon C, senofilcon C, senofil Nofilcon B, sinfilcon C, narafilcon A, narafilcon B, balafilcon A, samfilcon A, lotrafilcon A, lotrafilcon B, somofilcon A, riofilcon A, delefilcon A, verofilcon A, kalifilcon A, lehfilcon A, and the like.

[0046] Alternatively, the contact lens may include, consist essentially of, or consist of a silicone elastomeric material. For example, the contact lens may include, consist essentially of, or consist of a silicone elastomeric material having a Shore A hardness from 3 to 50. The Shore A hardness may be determined using conventional methods as understood by one of ordinary skill in the art (e.g., using method DIN 53505). For example, other silicone elastomeric materials may be obtained from NuSil Technology or Dow Chemical Company.

[0047] According to a second aspect, the present disclosure provides a method of manufacturing a contact lens. The method includes obtaining one or more colorants that absorb light having a wavelength of 450 nm to 495 nm and allow light having a wavelength of 500 nm to 750 nm to travel through. The method includes forming a diffractive optical element having a diffractive structure configured to focus visible light having a wavelength above 495 nm. The method includes forming a contact lens incorporating the diffractive optical element and the one or more colorants.

[0048] The method may also include the step of obtaining one or more compounds that absorb UV light. The step of forming a contact lens may also include incorporating the one or more compounds into the contact lens. The step of forming a contact lens may also include the step of molding a lens body around the diffractive optical element so that the diffractive optical element is embedded in the lens body. The step of forming a contact lens may also include the step of forming a layer incorporating one or more colorants. The step of forming a contact lens may also include the step of bonding the rear surface of the layer to the front surface of the lens body. The method may also include the step of applying an adhesive to the rear surface of the layer. The method may also include the step of applying an adhesive to the front surface of the lens body. The adhesive may be a transparent adhesive.

[0049] According to a third aspect, the present disclosure provides a method for correcting a user's vision. The method includes obtaining a contact lens according to the present disclosure. The method includes placing the contact lens on a surface of a user's eye. The method includes causing the contact lens to diffract light so that the light is focused on a retina of the user's eye.

[0050] The contact lens can be a molded contact lens. The contact lens can be formed, for example, by a cast molding process, a spin casting molding process, or a turning process, or a combination thereof. As understood by those skilled in the art, cast molding refers to molding a lens by placing a lens-forming material between a female mold member having a concave lens component-forming surface and a male mold member having a convex lens component-forming surface.

[0051] Contact lenses 100( Figure 1) has a contact lens body 105 formed of a silicone hydrogel material. The contact lens 100 includes a diffractive optical element 101 and a filter 103 formed of a mixture of colorants that together filter out light having a wavelength of 450nm to 495nm. The filter 103 also absorbs UV wavelengths that are harmful to the human eye. The filter 103 allows light having a wavelength of 500nm to 750nm to travel through it. The diffractive optical element 101 is centered on the optical axis 109 of the contact lens 100 and extends perpendicular to the optical axis. In a plan view, the diffractive optical element 101 is radially surrounded by a peripheral region 102 of the contact lens 100. The filter 103 is a mixture of colorants dispersed through the material of the lens body 105 indicated by the stippled shading in the figure. The diffractive optical element 101 is embedded in the lens body 105 so that it is surrounded by the lens body 105 on all sides. In a plan view ( Figure 1 ) in which the diffractive optical element 101 comprises a series of concentric annular regions 111.

[0052] Contact lenses 100( Figure 2 ) comprises a first portion 104 having a first refractive index and a second portion 106 comprising a liquid crystal cell that can be electrically switched between a matched state and a mismatched state. In the matched state, the liquid crystal cell has a refractive index equal to the first refractive index. In the mismatched state, the liquid crystal cell is "switched" so that it has a refractive index greater than the first refractive index. Figure 2 In the cross section shown in , the first portion 104 of the diffractive optical element 101 has a series of peaks extending outward from the optical axis 109 of the contact lens 100 toward the peripheral edge 107 of the contact lens. The second portion 106 has a corresponding shape so that it is aligned with the first portion 104 to create a continuous boundary between the two. When the second portion 106 is in a matched state, it has a refractive index equal to the refractive index of the first portion 104. When the second portion 106 is in an unmatched state, it has a refractive index greater than the refractive index of the first portion 104.

[0053] Prior art contact lens 200 ( Figure 3 ) contains a diffractive optical element 201. The contact lens 200 does not contain a filter that blocks light having a wavelength of 450 nm to 495 nm, so the full wavelength range of visible light can travel through the contact lens 200 and be incident on the diffractive optical element 201.

[0054] Figure 3 A pair of light rays 220 is shown incident on a contact lens 200 according to the prior art. The diffractive optical element 201 diffracts the light incident thereon. The refractive power of the diffractive optical element is given by the following equation:

[0055] P=2mλ / r^2

[0056] P is the optical refractive index in diopters, λ is the wavelength in meters, and r is the radius of the mth annular diffractive zone in meters. The refractive index of a given annular diffractive zone of a diffractive optical element varies with wavelength. This relationship causes chromatic aberration.

[0057] The diffractive optical element 201 has a characteristic wavelength of 600 nm. The diffractive optical element is designed to accurately focus light having the characteristic wavelength onto a target focus 210. The target focus of the contact lens is determined at the time of manufacture. Light having a wavelength shorter than the characteristic wavelength will be focused slightly further away from the contact lens than the target focus 210. Light having a wavelength longer than the characteristic wavelength will be focused slightly closer to the contact lens than the target focus 210. Figure 3 The diagram of FIG. 201 shows a pair of light rays 220 incident on a diffractive optical element 201. An optical axis 212 runs through the center of the diffractive optical element 201. A target focus 210 is located on this axis. A light ray 204 representing red light has a wavelength longer than the characteristic wavelength and is focused closer to the contact lens 200 than the target focus 210. A light ray 208 representing blue light has a wavelength shorter than the characteristic wavelength and is focused farther from the contact lens 200 than the target focus 210. A light ray 206 representing green light is focused closest to the target focus 210 between the two. The difference in focal length between the longer wavelength light ray 204 and the shorter wavelength light ray 208 is indicated by a dashed arrow 213.

[0058] Considering the diffractive optical element in isolation, the first diffractive zone of the diffractive optical element 201 having a diameter of 0.5 mm has an optical refraction of 4.8 diffraction at a wavelength of 600 nm. At 450 nm, the optical refraction of the first diffraction zone is 3.6 diffraction. At 750 nm, the optical refraction of the first diffraction zone is 6.0 diffraction. This gives a range of optical refraction of 2.4 diffraction. Since the optical refraction is the inverse of the focal length, the focal length varies from 0.28 m to 0.17 m, which gives a chromatic aberration of 0.11 m.

[0059] The contact lens 100 according to an embodiment of the present disclosure includes a diffractive optical element 101 ( Figure 4). The contact lens 100 includes a filter 103 that filters out light having a wavelength of 450nm to 495nm. Visible light having a wavelength of 496nm to 750nm is able to travel through the contact lens 100 and is diffracted by the diffractive optical element 101. The diffractive optical element 101 has a characteristic wavelength of 600nm. The diffractive optical element is designed to focus light having the characteristic wavelength precisely onto a target focus 310 on the optical axis 109. A pair of light rays 320 that have traveled through the filter 103 are incident on the diffractive optical element 101. A light ray 304 representing red light having a wavelength longer than the characteristic wavelength is focused closer to the contact lens 100 than the target focus 310. A light ray 306 of a shorter wavelength representing visible light that drops to a minimum value of 496nm is focused farther away from the contact lens 100 than the target focus 310. The difference in focal length between the longer wavelength light ray 304 and the shorter wavelength light ray 306 is indicated by a dotted arrow 313.

[0060] Considering the diffractive optical element in isolation, the first diffractive region of the diffractive optical element 101 having a diameter of 0.5 mm has an optical refraction of 4.8 diffraction at a wavelength of 600 nm. At 500 nm, the optical refraction of the first diffraction region is 4.0 diffraction. At 750 nm, the optical refraction of the first diffraction region is 6.0 diffraction. This gives a range of optical refraction of 2.0 diffraction. Since the optical refraction is the inverse of the focal length, the focal length varies from 0.25 m to 0.17 m, which gives a chromatic aberration of 0.08 m.

[0061] Figure 4 and Figure 3 The comparison of 100 and 101 shows how using filter 103 to block light having wavelengths of 450 nm to 495 nm serves to reduce the visible light spectrum that can travel through contact lens 100, and thus reduce the diffractive range of diffractive optical element 101. Reducing the diffractive range reduces the chromatic aberration produced by the diffractive optical element and reduces blur around the focal point. This provides a clearer and sharper image for the contact lens user.

[0062] A second embodiment of the present disclosure will now be described. Contact lens 400 ( Figure 5) includes a diffractive optical element 401 and has other features similar to those described with respect to the first embodiment; the differences will now be described. The contact lens 400 includes a lens body 405 and a layer 408 containing a filter 403. The diffractive optical element 401 is embedded within the material of the lens body 405 and aligned with the optical axis 409. The layer 408 has dispersed therein a mixture of colorants that together filter out light having a wavelength of 450nm to 495nm. The filter 403 also absorbs UV wavelengths that are harmful to the human eye. The layer 408 is bonded to the front surface 410 of the lens body 405 and covers the entire front surface 410 up to the peripheral edge 407 of the contact lens. The layer 408 containing the filter 403 allows light having a wavelength of 500nm to 750nm to travel through it and be diffracted by the diffractive optical element 401.

[0063] The diffractive optical element 401 has a first portion 404 and a second portion 406. The first portion 404 has a first refractive index. The second portion 406 is a liquid crystal unit that can be switched between a matching state and a mismatching state. In the matching state, the second portion 406 has a refractive index equal to the first refractive index. In the mismatching state (in Figure 5 ), the second portion 406 has a second refractive index greater than the first refractive index. Figure 5 , a first portion 404 of the diffractive optical element 401 has a series of peaks extending outwardly from the optical axis 409 of the contact lens toward the peripheral edge 407. A second portion 406 surrounds the peaks of the first portion 404 of the diffractive optical element 401. There is a continuous boundary between the material of the first portion 404 of the diffractive optical element 401 and the second portion 406 of the diffractive optical element 401. In a plan view (not shown), the diffractive optical element comprises a series of concentric annular regions. When the second portion 406 of the diffractive optical element 401 is switched to an unmatched state, and therefore has a different refractive index than the first portion 404, each annular region is a diffractive zone defined by a pair of peaks of the diffractive optical element.

[0064] The third embodiment of the present disclosure differs only slightly from the second embodiment. The differences will now be described. Contact lens 500 ( Figure 6) comprises a diffractive optical element 501, a lens body 505, a first layer 508a and a second layer 508b. A mixture of compounds that together filter out UV wavelengths that are harmful to the human eye is dispersed in the first layer 508a. The first layer 508a is bonded to the front surface 510 of the lens body 505 and covers the entire front surface 510 up to the peripheral edge 507 of the contact lens 500. The second layer 508b has dispersed therein a mixture of colorants that together filter out light having a wavelength of 450nm to 495nm. Both the first and second layers (508a and 508b) allow light having a wavelength of 500nm to pass through. The second layer 508b is bonded to the entire front surface 514 of the first layer 508a.

[0065] According to another embodiment, the manufacturing method 600 of the contact lens includes the following steps: Figure 7 ). A first step 601 includes obtaining one or more colorants that absorb light having a wavelength of 450nm to 495nm and allow light having a wavelength of 500nm to 750nm to travel through. Another step 603 includes forming a diffractive optical element (DOE) having a diffractive structure capable of focusing visible light having a wavelength above 495nm. Another step 611 includes forming a contact lens incorporating a diffractive optical element and one or more colorants. Figure 7 Optional steps are indicated by dashed boxes and required steps are indicated by solid boxes.

[0066] According to other embodiments, step 611 of forming a contact lens further comprises the following steps. Step 605 comprises molding a lens body around a diffractive optical element such that the diffractive optical element is embedded in the lens body. Step 607 comprises forming a layer incorporating one or more colorants. Step 609 comprises bonding a rear surface of the layer to a front surface of the lens body. According to other embodiments, prior to step 611 of forming a contact lens, the method comprises step 604 of obtaining one or more compounds that absorb UV light.

[0067] According to another embodiment, the method 700 for correcting the user's vision includes the following steps: Figure 8 ). A first step 702 includes obtaining a contact lens according to the present disclosure. A second step 704 includes placing the contact lens on a surface of an eye of a user. A third step 706 includes diffracting light incident on the contact lens so that the light is focused on the retina of the eye of the user.

[0068] Although the present disclosure has been described and illustrated with reference to specific embodiments, it will be appreciated by those skilled in the art that the present disclosure lends itself to many different variations not specifically described herein. By way of example only, possible variations will now be described.

[0069] In some alternative embodiments of the present disclosure, the contact lens may include a coating. The coating may be applied directly to the contact lens surface by various coating methods (e.g., spray coating, spin coating, solution casting, liquid phase surface deposition, or vapor phase surface deposition). Before the coating is applied to the contact lens surface, the contact lens surface may be treated, for example, using plasma treatment to improve bonding or adhesion to the coating layer. The coating may include one or more colorants configured to filter out light with a wavelength of 450nm to 495nm. The coating may be configured to allow light with a wavelength of 500nm to 750nm to travel through. The coating may be a filter. The coating may contain one or more compounds configured to absorb UV light.

[0070] Where reference is made to an entirety or element with known obvious or foreseeable equivalents in the foregoing description, then these equivalents are incorporated herein as if individually set forth. Reference should be made to the claims for determining the true scope of the present disclosure, which should be interpreted so as to encompass any such equivalents. The reader should also understand that entireties or features of the present disclosure described as preferred, advantageous, convenient, or the like are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such optional entireties or features, while having possible benefits in some embodiments of the present disclosure, may be undesirable and therefore may not exist in other embodiments.

Claims

1. A contact lens comprising a diffractive optical element, an optical filter, and an optical axis that travels through the optical filter and the diffractive optical element, wherein: The diffractive optical element is configured to focus visible light; and The filter is configured to filter out light having a wavelength of 450 nm to 495 nm.

2. The contact lens of claim 1, wherein the filter allows light having a wavelength of 500 nm to 750 nm to pass therethrough.

3. The contact lens of any one of claims 1 and 2, wherein the optical filter comprises one or more colorants.

4. The contact lens of any preceding claim, wherein the contact lens comprises a material having one or more colorants dispersed therein.

5. The contact lens of any one of claims 1 to 3, wherein the contact lens comprises a layer comprising the optical filter.

6. The contact lens of claim 5, wherein the layer forms the front surface of the contact lens.

7. A contact lens according to any preceding claim, wherein the diffractive optical element is embedded within the contact lens.

8. A contact lens according to any preceding claim, wherein the diffractive optical element is centered on the optical axis of the contact lens and is surrounded by a peripheral region of the contact lens.

9. A contact lens according to any preceding claim, wherein the characteristic wavelength of the diffractive optical element is from 500 nm to 750 nm.

10. A contact lens according to any preceding claim, wherein the filter absorbs UV wavelengths.

11. A contact lens according to any preceding claim, wherein the diffractive optical element comprises a diffractive structure that diffracts and refracts the light incident thereon.

12. A contact lens according to any preceding claim, wherein in a transverse cross-section passing through the optical axis, the diffractive optical element comprises a series of peaks and valleys having a first refractive index, wherein the valleys are filled with a material having a second refractive index.

13. The contact lens of any one of claims 1 to 11, wherein the diffractive optical element comprises a first portion having a first refractive index and a second portion comprising a liquid crystal cell switchable between a matched state and a mismatched state, wherein In the matching state, the refractive index of the liquid crystal unit is equal to the first refractive index; and In the unmatched state, the refractive index of the liquid crystal cell is different from the first refractive index.

14. A method of manufacturing a contact lens, comprising: Obtaining one or more colorants that absorb light having a wavelength of 450 nm to 495 nm and allow light having a wavelength of 500 nm to 750 nm to travel therethrough; forming a diffractive optical element having a diffractive structure configured to focus visible light having a wavelength above 495 nm; and A contact lens incorporating the diffractive optical element and the one or more colorants is formed.

15. The manufacturing method of claim 14, wherein forming the contact lens comprises the following method steps: molding a spectacle body around the diffractive optical element so that the diffractive optical element is embedded in the spectacle body; forming a layer incorporating the one or more colorants; and The rear surface of the layer is bonded to the front surface of the lens body.

16. The manufacturing method of claim 14, wherein prior to forming a contact lens, the method further comprises the step of obtaining one or more compounds that absorb UV light, and wherein the step of forming a contact lens comprises incorporating the one or more compounds into the contact lens.

17. A method for correcting a user's vision, comprising: Obtaining a contact lens according to any one of claims 1 to 13; placing the contact lens on the surface of the user's eye; and The contact lens diffracts light so that the light is focused onto the retina of the eye of the user.

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