Lens element

Abstract

The present invention relates to a lens element intended to be worn in front of a wearer's eye, comprising a substrate having a front surface and a rear surface, and an optical element located on one of the front or rear surfaces of the lens element. The optical element is realized in the form of a blind hole on the face, reducing the contrast on the wearer's retina and contributing to the control of myopia. At least one optical element has a PV value of 25 μm or less.

Description

[Technical Field]

[0001] The present disclosure relates to a lens element that is placed in front of a human eye to prevent, slow or control ocular refractive error, particularly myopia and hyperopia. The lens element is particularly an ophthalmic article.

[0002] The term "eyeglass article" is understood to mean in particular corrective or other lenses that can be used as eyeglasses, such as sunglasses, goggles, visors, etc., or contact lenses that are worn in direct contact with the user's eyes. [Background technology]

[0003] Myopia is characterized by the eye focusing distant objects in front of the retina. Hyperopia is characterized by the eye focusing distant objects behind the retina. Myopia is usually corrected with concave lenses. Hyperopia is usually corrected with convex lenses.

[0004] When vision is corrected using conventional single vision optical lenses, some people, especially children, experience inaccurate focus when viewing objects at close range, i.e., in a myopic state. Myopic children who have their far-sightedness corrected lack the ability to focus, so images of nearby objects are also focused onto the foveal region behind the retina.

[0005] These focusing problems can contribute to the progression of myopia, which in most of these people tends to worsen over time.

[0006] Foveal vision corresponds to a visual condition in which an image of a viewed object is formed by the eye in a central area of ​​the retina called the foveal region.

[0007] Peripheral vision corresponds to the perception of elements of the scene that are laterally displaced relative to the object being viewed, the images of which are formed in the peripheral parts of the retina, away from the foveal region.

[0008] Ophthalmic corrections provided to subjects with refractive errors are usually tailored to the foveal region. However, as is commonly known, the correction of peripheral vision must be weakened compared to the correction of foveal vision. Studies, particularly in monkeys, have shown that even simultaneous illumination of light perfectly focused on the fovea, focusing significantly behind the peripheral retina, can elongate the eyeball and exacerbate myopic impairment.

[0009] Therefore, there is a perceived need for a lens element that inhibits, controls, or at least slows the progression of abnormal eye refractive conditions such as myopia and hyperopia.

[0010] Patent document 1 in the name of the applicant proposes a solution by disclosing a lens element having a focus-shifting optical element which has the effect of defocusing the image onto the peripheral retina of the eye, particularly under standard wearing conditions.

[0011] However, it has been observed that some lenses with myopia-suppressing dot-shaped lens elements exhibit an unpleasant, cloudy appearance from the viewer's perspective. This hazy white veil can be easily seen when the lens elements are placed on a colored surface or a dark background, for example, when eyeglasses with such lens elements are placed on a dark table or on human skin. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] International Publication No. 2019 / 206569 [Non-patent literature]

[0013] [Non-Patent Document 1] S. Azouigui, Z. Silvestri, C. Zerrouki, S. Bouhtiyya, M. Plimmer, D. Spaltmann, A. Kovalev, M. Woydt, P. Pinot; “Angle resolved scattering as a tribological investigation tool for surface characterization”, Wear, Vol. 326-327, pp. 58-67 (March, 2015) Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention aims to provide an improved lens element that at least reduces or completely eliminates the cloudiness from the viewer's perspective, thereby realizing efficient control of myopia or hyperopia. [Means for solving the problem]

[0015] To achieve the above-mentioned object, the present invention proposes a lens element to be worn in front of a wearer's eye, comprising a substrate having a front surface and a rear surface, and a plurality of optical elements located on one of the front surface or the rear surface of the lens element. The plurality of optical elements are realized in the form of a plurality of blind holes on the face, and contribute to the control of myopia by reducing contrast on the wearer's retina. At least one optical element has a peak-to-valley dimension of 25 μm or less.

[0016] The present invention also proposes a method for manufacturing a lens element to be worn in front of a wearer's eye, the method comprising: a substrate having a front surface and a rear surface; and a plurality of optical elements arranged on one of the front or rear surfaces of the lens element. The plurality of optical elements are realized in the form of a plurality of blind holes on the face, which contribute to the control of myopia by reducing the contrast on the wearer's retina. At least one optical element has a PV value of 25 μm or less. The method may comprise a laser engraving step using a laser with an engraving wavelength of 355 nm or less, in particular 355 nm or 266 nm.

[0017] According to further aspects related to the lens element defined above, taken alone or in combination, The optical elements may be blind holes realized by laser ablation. The lens element may further comprise an anti-reflective coating. The lens element may further comprise a hard coat having a refractive index of 1.6±2%. The hard coat may contain a compound that enhances laser absorption in the range of 250 nm to 370 nm. In the aforementioned cases, the compound that enhances laser absorption may comprise a metal oxide or a colloid containing a metal. - the surface of the lens element present in the area and bounded by said optical element is 10 10 nm -3 Power spectral densities of ±10% may be expressed. The boundary of at least one blind hole (14) may protrude less than 5 μm from the surrounding surface (16) in which said optical element (14) is present. The PV value of an optical element is less than or equal to 15 μm. The substrate may exhibit 0% transmission for a 2 mm layer at the wavelength of laser ablation. The hard coat may exhibit an extinction coefficient (k) greater than 0.005, preferably greater than 0.05, in the wavelength range from 250 nm to 355 nm. The diameter of the plurality of blind holes may be 170 μm to 220 μm. The distance between the centers of two adjacent blind holes may be 300 μm to 420 μm. The haze level of the lens element may be 15%±5%. The lens element may have a circular central area (16C) that is not engraved. The uncarved circular central area may have a diameter of 3.5 m. The unengraved circular central region may be surrounded by an annular region in which the diameter of the blind holes gradually increases from 40 μm to at least 170 μm. In said method, the laser engraving step may comprise the use of laser pulses. The duration of the laser pulse may be between 10 μs and 100 μs. The laser beam may be focused when it strikes the lens element, with a spot size of 1250 μm. 2 ~12500μm 2 may be.

[0018] Other advantages and features will become apparent upon reading the diagram descriptions below. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a plan view of a lens element according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view of a lens element according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a plan view of a lens element according to another embodiment of the present disclosure. [Figure 4] 1 is a simplified cross-sectional view of a blind hole according to the present disclosure. FIG. [Figure 5] 1 is a graph showing PV values ​​as a function of mean visual score. [Figure 6] 10 is a photograph illustrating how the average visual score was calculated. [Figure 7] FIG. 3 is a schematic cross-sectional view similar to FIG. 2 of another embodiment. [Figure 8] FIG. 10 is a schematic cross-sectional view similar to FIG. 2 of yet another embodiment. [Figure 9] FIG. 2 is a plan view similar to FIG. 1 of yet another embodiment of a lens element of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0020] In all figures, the same elements are labeled with the same reference numerals.

[0021] The following embodiments are merely examples. Although one or more embodiments may be mentioned herein, the present invention is not limited to these embodiments. Also, features described in connection with one embodiment may relate to another embodiment, even if not explicitly mentioned. Simple features of different embodiments may be combined to provide further implementations.

[0022] As used herein, the "front surface" or "rear surface" of a layer, lens element, or surface is determined by the propagation of light rays through the ophthalmic lens toward the eye when an ophthalmic device equipped with the ophthalmic lens is worn on the wearer's face. Thus, the "front surface" is always the surface farthest from the wearer's eye, i.e., closest to the field of view, and the "rear surface" is always the surface closest to the wearer's eye. The terms "upstream" and "downstream" are used in reference to the propagation of light from the outside through the lens element toward the retina of the wearer's eye when the lens element is worn on the wearer. Thus, when light first passes through a first object, then through a second object, and then toward the wearer's retina, the first object (surface, layer, image, etc.) is located upstream of the second object.

[0023] For example, an image is located upstream or in front of the retina of the wearer's eye if the image is in front of the retina, between the pupil and the retina.

[0024] Conversely, when light first passes through the second element, then the first element, and then toward the wearer's retina, the first object is "downstream" of the second object, and therefore the wearer's retina is downstream of both the lens element and the wearer's pupil.

[0025] The present invention relates to a lens element intended to be worn in front of a wearer's eye.

[0026] In the description of this disclosure, the term "lens element" may refer to a lens blank, an uncut optical lens, an eyeglass optical lens that has been edged to fit a particular eyeglass frame, or an ophthalmic lens.

[0027] As shown in Figures 1 and 2, a lens element 10 according to the present invention comprises a substrate 11 having a front surface 12F and a rear surface 12R. As shown in Figure 2, light entering the ophthalmic article 1 is indicated by arrow 5, and the eye of wearer W represents the wearer of lens element 10. Thus, field of view 7 is located on the side of arrow 5, and the eye of wearer W looks through lens element 10. Upstream of lens element 10 is located the eye of observer O, facing in the direction of the eye of wearer W. The eye of wearer W is located downstream of lens element 10.

[0028] The substrate 11 is made of, for example, a plastic material, for example, a polymer substrate such as a thermosetting resin, particularly a polymer (e.g., urea urethane), or a thermoplastic material, particularly a polyamide (PA) such as nylon, or polycarbonate, polyester, or TRIVEX®. Alternatively, a PET or TAC film or other suitable material may be provided on either surface of the substrate, for example, by lamination. In the example of FIGS. 1 and 2, a plurality of optical elements 14 are arranged on the front surface 12F of the lens element 10. The optical elements 14 are spaced apart from one another on the front surface 12F.

[0029] In an alternative example not shown, optical element 14 may be disposed on rear surface 12R, or may be disposed on both front surface 12F and rear surface 12R. In examples where a film material is present on substrate 11 as described above, optical element 14 may be disposed on the film material.

[0030] The area of ​​the front surface 12F other than the area formed by the optical elements 14 is defined as a refractive area (surface) 16. In other words, the refractive area 16 is complementary to the area occupied by the optical elements 14.

[0031] The refractive region 16 is configured to provide the wearer with a first optical power based on the wearer's prescription to correct the anomalous refraction of the wearer's eye under normal wearing conditions, particularly in central vision. The purpose of the refractive region 16 is to focus incident parallel light onto the retina.

[0032] The wearing state is understood as the position of the lens element 10 relative to the wearer's eye and is defined, for example, by the cornea to lens distance, pupil to cornea distance, center of rotation of the eye (CRE) to pupil distance, CRE to lens distance, and wrap angle.

[0033] As can be seen in FIG. 2, the optical elements 14 are realized as blind holes, which are also referenced with the numeral "14."

[0034] Such blind holes 14 can be produced by various methods, in particular by laser ablation, but also by mechanical drilling, percussion, etching, embossing, molding with a specific mold that exhibits specific protrusions, 3D printing of a surface with holes, or other related techniques.

[0035] The lens element 10 further includes a circular, unsculpted central region 16C that is part of the refractive region 16 and is designed to be positioned in front of the wearer's pupil when worn. This circular, unsculpted central region 16C is also called a COCA (circle of clear aperture). The blind hole 14 may surround the circular, unsculpted central region 16C.

[0036] The diameter of the circular unengraved central region 16C is, for example, 3.5 mm.

[0037] In the above example, the blind holes 14 are arranged in circular concentric circles around the circular central region 16C.

[0038] Another configuration is shown in Figure 3, which is similar to Figure 1 and shows a top view of lens element 10. According to this embodiment, the blind holes are arranged according to a random square array. Arrow A indicates an enlarged / zoomed view of the blind holes.

[0039] The diameter of the blind holes 14 according to the above-described embodiment is particularly in the range of 170 μm to 220 μm.

[0040] The distance between the centers of adjacent blind holes 14 is, for example, between 300 μm and 420 μm.

[0041] The optical element formed as a blind hole in the present disclosure is intended to generate unfocused light, thereby reducing contrast in front of the retina, for example, and slowing the progression of myopia. The aforementioned blind hole 14 provides a scattering effect to the light rays incident on the wearer's retina, thereby contributing to the control of the progression of myopia.

[0042] Reference is now made to FIG. 4, which is a simplified cross-sectional view (cross-sectional profile) of a blind hole 14 according to the present disclosure.

[0043] Blind hole 14 is generally circular (see FIG. 1 ) having straight sidewalls 14S, a peripheral boundary 14B that may protrude relative to refractive region 16, and a terminal end 17. Straight sidewalls 14S extend from boundary 14B to terminal end 17 of blind hole 14. Straight sidewalls 14S may be angled relative to the longitudinal axis of blind hole 14 or may be parallel to the longitudinal axis. Terminal end 17 is recessed relative to boundary 14B and relative to refractive region 16, e.g., relative to the surface defining refractive region 16.

[0044] 4 also defines a parameter PV (peak-to-valley) and a parameter BP (border protrusion). The parameter PV is the depth of the blind hole 14 relative to the height of the boundary 14B. The parameter BP is the protrusion height of the boundary 14B relative to the refractive region 16.

[0045] The inventors have found that an optical element 14 having a PV value of 25 μm or less, particularly 15 μm or less, results in a lens element 10 that has a positive effect on myopia control while reducing the perception of cloudiness from the observer's perspective.

[0046] Such optical element 14 may have a PV value of at least 3 μm, preferably at least 4 μm, to effectively control myopia.

[0047] The results of a study in which lens elements having different PV values ​​were manufactured and evaluated are shown in Figure 5. Figure 5 is a graph showing the PV value of a lens element as a function of average visual score, obtained using the process described below.

[0048] The linear regression line 100 shows the mean visual score as a function of the value of the parameter PV for lens elements whose substrates are made of polycarbonate material.

[0049] A linear regression line 102 shows the mean perception score as a function of the value of the parameter PV for lens elements whose substrates are made of TRIVEX® material.

[0050] In all of the above cases, the smaller the PV value, the better the mean perception score.

[0051] A test protocol was defined to obtain a mean visual score.

[0052] Lens element 10 was examined by two independent observers under specified lighting conditions using a CIE standard D65 illuminant in a room with no overhead lighting and blackout curtains.

[0053] Two criteria (described below) were analyzed in two different contexts. One context was a Caucasian mannequin M, as shown in Figure 6.

[0054] The black background provided a higher contrast environment for observing the lens elements, increasing the likelihood of identification results, while Mannequin M provided a more realistic environment, simulating the situation of another person observing the wearer.

[0055] The observer was asked to assess the following two criteria: => Visibility of optical element engraving / blind hole 14 => Visibility of COCA (effective aperture edge) corresponding to the unengraved circular central area 16C was evaluated.

[0056] Observers used a continuous scale ranging from 1 to 5, with 1 representing poor visibility and 5 representing excellent visibility.

[0057] Thus, a lower visual score represents a perceived reduction in the white haze on the lens element 10 by an observer observing the wearer of the lens element 10 .

[0058] It was believed that the less visible the COCA, the better the lens element 10 would perform.

[0059] The optical elements / blind holes 14 are arranged in an annular shape, with the inner circular boundary forming COCA16C, and the outer circular boundary of the annulus being either the edge of the lens element or a smaller feature within the lens element. The annulus may be non-circular. It was believed that the less visible the engraved optical elements / blind holes 14, the better the performance of the lens element 10. Note that the "performance" referred to above was considered to be aesthetics, not the ability of the blind holes to control myopia.

[0060] Figure 5 shows that the difference in peak-to-valley (PV) has a clear effect on the mean visual score.

[0061] Furthermore, it has been observed that the performance of the lens element from the observer's perspective is further improved when the blind hole 14 protrudes less than 5 μm (BP<5 μm) from the surrounding surfaces forming the refractive region 16. In particular, the optical element / blind hole 14 becomes less visible to the observer.

[0062] Furthermore, the surface of the lens element 10, in the example shown, the front surface 12F, has an annular portion around the COCA (e.g., as in FIG. 1), and -1 From 80mm -1 Within the spectral and spatial bands up to 10 10 nm -3 When placed within an area bounded by optical elements 14 having a power spectral density of (±10%), a "fading" effect on the visibility of the blind holes 14 and COCA 16C was observed, making the blind holes 14 and COCA less visible and reducing the average visual score of the lens elements.

[0063] The power spectral density (PSD) was measured optically by taking surface height measurements with an optical interferometer.

[0064] The calculation of the power spectral density (PSD) from the elevation map was performed according to the contents of non-patent document 1.

[0065] The power spectral density (PSD) was calculated within an area containing multiple blind holes 14. Typically, the PSD can be determined within a 4 mm x 4 mm square area, which corresponds to approximately 60 blind holes 14 within the sample under consideration.

[0066] Disclosed herein is a method for manufacturing a lens element. As mentioned above, the blind hole 14 may be formed, inter alia, by laser ablation.

[0067] Laser ablation comprises a laser engraving process using a laser with an engraving wavelength below 355 nm, in particular 355 nm or 266 nm.

[0068] The laser engraving process comprises the use of laser pulses, the pulses having a duration of, for example, 10 μs to 100 μs.

[0069] The shorter the wavelength of the laser light, the longer the energy required for ablation. So, for example, a 266 nm laser wavelength has a pulse width of 30 μs, while a 355 nm laser wavelength has a pulse width of about 85 μs.

[0070] In the case of laser engraving, the laser beam is focused and has a diameter of 1250 μm when it strikes the lens element 10. 2 ~12500μm 2 The spot size is

[0071] FIG. 7 shows a further development of lens element 10 which differs from FIG. 2 in that lens element 10 includes a hard coat 18 disposed on substrate 11.

[0072] An example of hard coat 18 is a single or double layer of polysiloxane having a thickness of 2.5 μm to 4.5 μm.

[0073] During laser ablation, blind hole 14 is drilled through hard coat 18 to substrate 11 until a certain depth is reached, and the PV value of blind hole 14 represents the thickness of hard coat 18 .

[0074] To facilitate laser ablation for laser drilling of blind holes, hard coat 18 has a refractive index of 1.6±2%.

[0075] Improved laser ablation is achieved when the hard coat contains a compound that enhances laser absorption between 250 nm and 370 nm. Such compounds that enhance laser absorption include, for example, metal oxides or colloids containing metals. Examples include colloids of zirconium, tantalum, titanium, or tin, although zirconium or tantalum colloids have lower absorption than titanium colloids, and even lower absorption than tin colloids. In other words, the use of tin or titanium colloids results in a more aesthetically pleasing product.

[0076] Further, a further parameter of the hard coat 18 for enhancing engraving and obtaining an improved average visual score relates to an extinction coefficient k>0.005 in the wavelength range of 250 nm to 355 nm, and preferably 0.05 in the wavelength range of 260 nm to 355 nm. <k<0.5である。

[0077] Furthermore, enhanced engraving and improved average visual scores are achieved when the substrate exhibits non-zero absorption with zero transmission in the wavelength range of 250 nm to 355 nm, corresponding to the laser's ablation wavelength. Examples include substrates incorporating absorbing compounds, such as 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, which function as UV absorbers. This compound absorbs UV radiation between 340 nm and 355 nm, depending on the specific composition, and is compatible with nearly all synthetic resins.

[0078] "Most organic materials transparent in the visible light range absorb light close to 266 nm without the need for additional compounds, so using a laser with a wavelength close to 266 nm can achieve better performance. Furthermore, the absorption occurs directly in the polymer matrix material, rather than within a compound. This makes marking easier to control."

[0079] According to a further development shown in FIG. 8, an anti-reflective coating 20 is interposed between the substrate 11 and the hard coat 18, which also contributes to improved engraving and an improved average visual score.

[0080] Laser ablation opens blind holes through hard coat 18, anti-reflective coating 20, and a portion of substrate 11. In Figure 8, as in other figures, the size of blind holes 14 is exaggerated for illustrative purposes.

[0081] The lens element 10 according to the present disclosure and according to all the different embodiments exhibits a haze level of 15%±5% in transmission as specified by the ASTM D-1003 standard.

[0082] According to a further embodiment shown in Figure 9, the unengraved circular central area 16C is surrounded by an annular area 16AZ, where the diameter of the blind hole 14 gradually increases from a first diameter (e.g., 40 μm) to a second diameter (e.g., at least 170 μm). As indicated by the arrow, the width of the annular area 16AZ, which can be considered a "transition area," is, for example, 1.5 mm. This element particularly contributes to making the COCA 16C less visible.

Claims

1. A lens element placed in front of a wearer's eye, comprising: a substrate having a front surface and a back surface; a plurality of optical elements disposed on one of the front surface or the rear surface of the lens element; Equipped with The plurality of optical elements are realized in the form of a plurality of blind holes on the surface of the lens element, which reduce contrast on the retina of the wearer and contribute to suppressing myopia; The peak-to-valley dimension of at least one optical element is 25 μm or less; Lens element.

2. the optical elements are blind holes realized by laser ablation; The lens element of claim 1 .

3. further comprising an anti-reflective coating; The lens element of claim 2 .

4. further comprising a hard coat (18) having a refractive index of 1.6±2%; The lens element of claim 1 .

5. The hard coat has a compound that enhances laser absorption in the range of 250 nm to 370 nm. The lens element of claim 4 .

6. The laser absorption enhancing compound comprises a metal oxide or a metal-containing colloid.

6. The lens element of claim 5.

7. The front surface of the lens element within the area bounded by the plurality of optical elements is 10 １０ nm －３ Expresses power spectral density within ±10% The lens element of claim 1 .

8. a boundary of at least one blind hole protruding less than 5 μm from the peripheral surface of the lens element in the region where the plurality of optical elements are provided; The lens element of claim 1 .

9. The PV value of the one optical element is 15 μm or less. The lens element of claim 1 .

10. the substrate exhibits a transmittance of 1% or less, preferably 0.1% or less, more preferably 0.01% or less for a 2 mm layer at the wavelength of ablation; The lens element of claim 2 .

11. the hard coat exhibits an extinction coefficient (k) greater than 0.005, preferably greater than 0.05, in the wavelength range of 250 nm to 355 nm; The lens element of claim 4 .

12. 1. A method of manufacturing a lens element to be placed in front of a wearer's eye, comprising:

1. A method comprising: a substrate having a front surface and a rear surface; and a plurality of optical elements disposed on one of the front surface or the rear surface of the lens element; The plurality of optical elements are realized in the form of a plurality of blind holes on the surface of the lens element, which reduce contrast on the retina of the wearer and contribute to suppressing myopia; the peak to valley dimension of at least one optical element is 25 μm or less; The method comprises a laser engraving step using a laser having an engraving wavelength of 355 nm or less, in particular 355 nm or 266 nm.

13. The laser engraving process comprises the use of laser pulses. The method of claim 12.

14. The duration of the laser pulse is between 10 μs and 100 μs; The method of claim 12.

15. The laser beam is focused and reaches a wavelength of 1250 μm when it strikes the lens element. ２ ~12,500 μm ２ having a spot size of The method of claim 12.

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