JP2010507834A - Multi-layer refractive index progressive lens - Google Patents

Abstract

The present invention relates to a refractive index gradient type progressive addition eyeglass lens. This lens provides improved optical properties and a wide field of view. This lens includes a plurality of lens portions that are laminated in the axial direction with a continuous curvature (curvature) and coupled together. This lens has at least one refractive index gradient portion extending in a direction transverse to the meridian of the lens. The gradient functions as a progressive intermediate vision zone between visual points of different refractive indices. That visual point provides the refractive power for the corresponding visual part of the lens. The other layers of the lens have a refractive index that varies in a generally constant or similar manner.
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Description

  This application claims the benefit of US provisional application serial number 60 / 854,469, filed October 24, 2006.

  The present invention relates to a refractive index gradient type progressive (cumulative multifocal) addition spectacle lens. The spectacle lens provides improved optical properties and a wide field of view. The spectacle lens includes a plurality of lens portions that are laminated in the axial direction and joined together and that are continuously curved. At least one of the plurality of lens portions has a refractive index gradient oriented transverse to the meridian of the lens. The refractive index gradient functions as a progressive intermediate visual acuity zone between sight parts with different refractive indices. These vision parts provide the refractive power of the corresponding vision part of the lens. The other layers of the lens have a refractive index that is generally constant or varies in the same way.

  Progressive add-on eyeglass lenses are visual aids used in the management of presbyopia in which the regulatory function of the eye is partially or wholly lost. The American Vision Council advocates progressive lenses as lenses designed to provide correction of multiple viewing distances. At the multiple viewing distances, the power varies continuously rather than discretely. The change in the power of the progressive lens can be obtained by changing the curved surface of a certain lens and / or the refractive index of the optical material.

  Many refractive index type lenses have been proposed for use as progressive add-on lenses. These lenses provide a power change or power gradient. The change in refractive power or gradient of refractive power is referred to as the progressive intermediate vision zone or progressive intermediate transition zone of the lens, depending on the change in the refractive index of the optical medium constituting the lens. They theoretically provide the benefit of reducing or eliminating the astigmatism (astigmatism) associated with the non-rotating subject aspheric type common to conventional progressive addition lenses.

  Due to the problems associated with these designs, including manufacturing problems and difficulties, refractive index progressive power lenses have not been commercialized. In order to provide adequate power for both hyperopia and myopia functions, a significant amount of refractive index change is required of the optical material. Ion exchange methods proposed to achieve refractive index changes tend to provide both an unfavorable refractive index profile and not satisfying the power changes required for progressive addition eyeglass lenses. Similarly, lenses obtained by the diffusion method do not provide adequate add power and have not achieved commercial success.

  Naujokas, US Pat. No. 6,057,049 describes a multifocal plastic ophthalmic lens. The lens has a main lens portion having one refractive index and a sub lens portion having a different refractive index, and has a constant refractive index therebetween. The plastic material is manufactured by a process in which the monomer is gradually diffused and polymerized at the interface established between the monomer liquids in an isothermally controlled environment (condition).

  First, the lens can provide distant vision properties and near vision properties. The ray tracing of the lens according to the parameters described in this document is to obtain a diopter equivalent to 1 diopter only when a configuration with a considerably high plus power is used. It shows that you can. Using the refractive indices of 1.5 and 1.6 described in that document, the calculated plus power of 4.714 diopters is a slightly higher power of 5.714 diopters in the near vision part. In order to obtain it is needed for the distance vision part. Therefore, this lens is only effective for lenses that require high plus power correction for distance vision. Furthermore, when the front or rear surface of the lens is processed according to a prescription in which the cylindrical power is described, the cylindrical power changes and causes aberrations as a result of the change in refractive index.

  U.S. Pat. No. 6,053,097 to Guilino et al. Describes a multifocal ophthalmic lens. The multifocal ophthalmic lens includes a distance portion having a refractive power designed for a distance vision, a near portion having a refractive power designed for a near vision, and a main line of sight. And an intermediate portion whose refractive power continuously increases at least partially from the refractive power of the distance portion to the near portion. The refractive index of the lens material varies along at least the main line of sight in the middle so as to contribute at least in part to correcting aberrations and increasing refractive power. According to the detailed description, the two progressive ophthalmic lenses in front of the left or right eye have a visual main point (farsighted reference point) BF for far vision and a visual main point (myopia) for near vision. Reference point) Bn. Further, the distances y′BF and y′BN from the apex of the lens to the hyperopic reference point or the myopic reference point have values of y′BF = 4.0 mm and y′BN = −14 mm.

  In other words, the main point of far vision is 4 mm above the apex of the lens, and the main point of near vision is 14 mm below the apex of the lens. Also, as described in the detailed description, the refractive index function is a) simply a function of the coordinate y ′ such that by changing the refractive index, an increase in refractive power can only be obtained along the principal meridian. Or b) not only the increase of the refractive index along the main meridian but also the correction of the image error on the main meridian is a function of the coordinates y ′ and x ′ as caused by the change of the refractive index. is there. They are described in FIGS. 4a and 4b of Patent Document 2, respectively.

  As shown in FIG. 4a, the refractive index decreases from below the distance vision main point 4 mm above the apex of the lens toward the near vision main point of −14 mm. And it has decreased more greatly below the -14 mm point. In fact, the refractive index varies most dramatically from below the -14 mm point to the -20 mm point (1.57 to 1.51 over 6 mm (0.06 scale unit)). Moreover, it changes comparatively small at 4 mm point of distance vision from the top of -14 mm point (1.57 to 1.604 (0.034 scale unit) over 18 mm). This meaning indicates that the so-called near-use portion has the largest change in refractive power.

  Therefore, it fits more by the definition of the middle part. Moreover, it has shown that the intermediate part of 4 mm--14 mm has a comparatively small change of refractive power. Therefore, it conforms with the definition of the near part. Lenses with completely different refractive properties are required to provide the good optical properties of progressive ophthalmic lenses.

  U.S. Pat. No. 6,053,097 to Guilino et al. Describes an ophthalmic lens. The ophthalmic lens has a front surface, an interface facing the eye, and a refractive index that varies. The lens contributes to correction of aberrations. Ophthalmic lenses are distinguished by having at least one system of surfaces with a known level (n (x, y, z) = constant) having a constant refractive index. The surfaces are the same distance at all points in the normal direction of those surfaces (parallel surfaces) and intersect the axis connecting the lens vertices of the front surface and the surface facing the eye.

  Patent Document 3 describes a lens having a refractive index change. The change in refractive index depends on both the coordinate z in the direction of the connecting axis at the apex of the lens and the coordinates x and y of the axis orthogonal to the connecting axis. Therefore, it is allowed to correct the aberration and to minimize the critical thickness of the lens under normal conditions. According to the detailed description, the gradient is used to generate astigmatism and / or progressive power in a surface design that contributes only partially or does not contribute to astigmatism and / or progressive power. Used.

  Most of U.S. Patent No. 6,057,033 describes the use of an axial refractive index gradient or a modified axial refractive index gradient for aberration correction and to minimize the critical thickness of the lens. Coincidentally, there is a mention of the use of progressive addition eyeglass lenses for such refractive index gradients. Such a design is very similar to that described in US Pat. No. 6,057,097 filed in the United States by the same inventor after a year before the filing date of US Pat. With regard to whether the refractive index increases or decreases with increasing Z value, such a progressive lens has a similar or identical problem as that of the above-mentioned Patent Document 2.

  In Blum et al., US Pat. The lens contains at least three different layers of composite material that are utilized separately. Each layer has a different refractive index. These layers make it possible to provide a multifocal progressive lens that changes naturally with a wide vision when looking from near to far. The transition zone disposed between the base layer and the outer layer includes different transition layers or multiple transition layers that are utilized separately. The transition layer has an effective refractive index that is intermediate between the refractive index of the base layer and the refractive index of the outer layer. The refractive index is preferably close to the geometric average of the refractive index of the base layer and the refractive index of the outer layer. The transition layer includes a plurality of transition layers having different distinct refractive indices.

  In the lens invention, the refractive index of the base layer, the outer layer, and the transition layer is constant in each layer. A variable thickness region defining a multifocal progressive zone is included in the lens design. The technique used for transition zones with intermediate refractive indices is used to provide a multifocal progressive area that is as invisible as possible.

  If the preform has a refractive index of about 1.50 and the outer layer has a refractive index of about 1.70, as described in US Pat. The refractive indices of the layers are about 1.54, 1.60 and 1.66 as layers going from the preform to the outer layer. In the present invention, the gradient rate does not contribute to the progressive power in the patent documents mentioned above. Rather, in those patent documents, the variable thickness region defining the multifocal progressive zone is in the lens.

  Dreher, US Pat. No. 5,697,049, describes a multifocal progressive lens or progressive lens composed of a layer of an index variable material such as epoxy sandwiched between two lens blanks. The epoxy inner coating (aberrator) has a vision zone configured to correct aberrations in the patient's eyes and higher order aberrations. The index variable coating that constitutes the inner layer of this lens does not have the progressive power (add power) of the lens. Rather, as described in U.S. Patent No. 6,057,059, the indicator variable coating corrects the patient's eye aberrations. The lens has many limitations typical of aspheric progressive lenses.

U.S. Pat. No. 3,485,556 US Pat. No. 5,042,936 US Pat. No. 5,148,205 US Pat. No. 5,861,934 US Pat. No. 6,942,339

  Based on the foregoing description, it has been found that there is a need to provide a refractive index gradient type progressive eyeglass lens that solves the problems associated with each patent document and in particular improves the optical properties. The benefit comes from a multilayer lens with a refractive index gradient. The refractive index gradient provides the power change required for visualization over distance vision. Accordingly, it is a main object of the present invention to provide a multi-layer progressive lens. The multi-layer progressive lens includes at least one layer having a refractive index gradient that provides a region of progressive intermediate vision.

  Another object of the present invention is to provide a refractive index gradient progressive lens in which the refractive index gradient is oriented transverse (typically from the lens top to the bottom) with respect to the meridian of the lens. The refractive index gradient changes gradually and continuously according to a half sine waveform or a sinusoidal waveform.

  Another object of the present invention is to provide a refractive index gradient progressive lens comprising two layers: one layer having a refractive index gradient and the other layer having a surface obtained according to a patient's prescription. .

  Another object of the present invention is a refractive index gradient progressive comprising two layers so as to effectively increase the refractive index difference and the power difference between the distance and near vision portions of the lens. Is to provide a lens. Each layer has a refractive index gradient profile and a power of opposite sign (plus or minus) to the other layer.

  Another object of the present invention is to provide a refractive index gradient type progressive lens including three layers. Two adjacent layers have a refractive index gradient profile and a frequency of opposite sign to the other layer. The third layer has a surface obtained according to the patient's prescription.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient including two layers. Each layer has a refractive index gradient profile and a power of opposite sign to the other layer, and whether each refractive index gradient is aligned or misaligned One of them.

  Another object of the present invention is to provide a refractive index gradient type progressive lens including three layers. Two adjacent layers have a refractive index gradient profile and a power of opposite sign to the other layer. The third layer has a surface obtained according to the patient's prescription. Each refractive index gradient is either aligned or not aligned.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient profile. All layers of the lens have a continuous curved surface.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient profile. The lens does not have a width-limited corridor with a limited width of progressive intermediate vision, and the progressive intermediate vision portion and the near vision portion extend to the side boundary of the lens.

  Another object of the present invention is to provide a refractive index gradient type progressive lens that may be made within the range of the height of the progressive intermediate vision portion. The refractive index gradient type progressive lens includes a progressive intermediate vision portion smaller than the progressive intermediate vision portion typically provided in an aspherical progressive lens.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. The gradient index progressive lens utilizes only a curved spherical surface on the surface of a layer having a refractive index gradient. The lens provides excellent optical properties.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. A gradient index progressive lens utilizes one or more rotating object aspheric surfaces to correct high order aberrations and provide a wide range of optically corrected molds for eyeglass lens applications.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient including a plurality of thin layers. Each layer includes a refractive index gradient profile and a power of opposite sign to the adjacent layer. The lens thickness is comparable to that of a standard eyeglass lens with a similar add power.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient in the form of a doublet or triplet fullnel lens.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. The inclination of the non-optical functional steps (steps that are not optically functional) of the Furnell surface corresponds to the patient's gaze angle, so that it does not specifically disturb the light rays from the object in the peripheral field of view. Therefore, the efficiency of the lens is increasing.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. The inclination of the non-optical functional steps (steps) on the Furnell surface corresponds to several angles of the patient's gaze angle, thereby partially limiting the obstruction of light rays from the object in the peripheral field of view. Therefore, the efficiency of the lens is increasing.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. The shape of the lens is not flat, but rather curved like an eye. The inclination of the non-optical functional steps (steps) on the surface of the Furnell corresponds to the patient's gaze angle so that it does not specifically disturb the light rays from the object in the peripheral field of view. Therefore, the efficiency of the lens is increasing.

  Another object of the present invention is to provide a refractive index gradient type progressive lens having a refractive index gradient. The shape of the lens is not flat but rather curved like an eye. The inclination of the non-optical functional steps (steps) on the Furnell surface corresponds to several angles of the patient's gaze angle, thereby partially limiting the obstruction of light rays from the object in the peripheral field of view. Therefore, the efficiency of the lens is increasing.

  These objectives and advantages and other objectives and advantages are realized by a progressive lens that has a continuous curvature (curvature) and obtains progressive intermediate vision and increased power of near vision via the refractive index change of the lens . Due to the properties and importance of such refractive index gradients, the lens of the present invention can provide improved vision and high add power in a thin configuration, with minimal astigmatism. it can.

  The lens of the present invention uses one or more refractive index gradient layers including multilayer lenses. The index gradient profile corresponds to the lens region that provides a field of view over a range of lens powers. The refractive index gradient extends transversely from the meridian (generally the lens top to bottom) of a lens having a substantially constant refractive index from one surface of the layer to the other. The refractive index gradient is defined by a refractive index change rate suitable for providing a smoothly changing power change through the progressive middle of the lens.

  The refractive index gradient generally follows a half or sinusoidal curve from a minimum value to a maximum value (π / 2 to 3π / 2). Thus, the rate of increase and decrease of the refractive index change in the generally vertical direction from the upper part of the distance vision part of the lens to the lower part of the near vision part provides a gradual increase and a gradual decrease in power. . On the other hand, there is substantially no change in refractive index in a direction that is generally orthogonal along the gradient. The terms vertical and orthogonal with respect to the gradient rate profile are general terms and do not specify an exact angle of directionality.

  The refractive index and its lens power are generally constant in the direction perpendicular to the gradient. Therefore, as with a conventional aspherical progressive lens, vision through the progressive intermediate vision portion of the lens is not limited to the width or visual path. Rather, the effectiveness of the progressive intermediate vision portion extends sufficiently along its width, such as the far vision portion above the progressive intermediate vision portion and the near vision portion below the progressive intermediate vision portion. The range or length (distance) of the refractive index gradient that defines the progressive intermediate lens portion should be sufficient to provide important optical properties, for example, varying from approximately 10 mm to 20 mm.

  Astigmatism (astigmatic) power may have been thought to arise from such a "unidirectional" refractive index gradient, but the refractive index uniformity of the lens at any point of the lens Eliminates the occurrence of such astigmatism. Rather than astigmatism, such astigmatism power is a distortion aberration that manifests as visual compression or extension of the object seen through the progressive intermediate vision section. The extent to which this occurs depends on the steepness of the gradient profile. More importantly, the astigmatism in the lens of the present invention is dramatically reduced and a clear image is obtained across the entire width of the lens.

  Developments in the field of polymer chemistry over the last few years have yielded extremely high refractive index materials suitable for use in ophthalmic lenses. Some of the materials have a refractive index greater than 1.7 (some have a refractive index close to 1.8). By using one of the above-described high refractive index optical materials or other high refractive index optical materials together with a compatible low refractive index optical material (having a refractive index of 1.3 to 1.5), A refractive index gradient profile is obtained with a large refractive index difference suitable for use in the invention. As a result, the lens according to the invention is produced with a minimum center thickness and edge thickness. For example, in one embodiment of the present invention, a 48 mm diameter lens that provides a “0” power in the distance vision portion of the lens and an addition power of 2.5 diopters in the near vision portion of the lens is As thin as 1.76 mm thickness and 1.13 mm edge thickness.

  Various spraying, mixing, diffusing or other processing methods are utilized to provide the desired refractive index properties in a constant and repeatable state. For example, atomization techniques using two or more spray guns can produce various blends of resin compositions on a common deposit. The spray gun contains mutually compatible resins of different refractive indices, moves together along a linear path or arcuate path, and is 10-20 mm wide, overlapping deposit areas or common deposits A deposit having a region is produced. Depending on the size and shape of each deposit deposited, the overlap or common portion has the greatest amount of material in the portion of the deposit sprayed from each spray gun near the center of the deposit area, The amount of material changes so that the amount of material farthest towards the edge of the deposit area is minimal. The gradually changing composite mixture of the two resins in this common area (part) corresponds to the refractive index of one substance to the refractive index of the other substance (according to the sinusoidal curve described above). This causes a change in refractive index. The composite resin material is polymerized chemically or with light, otherwise solidified.

  Another gradient rate manufacturing method involves a controlled diffusion process using a dissolvable polymer membrane. The polymer film defines a predetermined interface shape and separates two optical resins having different refractive indexes. The polymer film once dissolved by one or both of the optical resins provides an accurate liquid interface for mixing and diffusion. Further methods include the use of special density dispersed particles. The particles accelerate and accelerate the mixing, blending and diffusion processes by movement of the particles through the liquid complex by gravity, buoyancy or centrifugal force.

  In the case of movement by gravity, for example, high-density micron-sized particles are dispersed on the top of most resin compositions. Then, the particles are stabilized throughout the liquid body through natural fall. Each particle draws a small amount of the upper resin with a certain refractive index to the lower resin with a different refractive index, and in the area just below the original interface, complete mixing and mixing of two adjacent liquids in the region. I will provide a. Once the particles have settled sufficiently, the liquid composition is polymerized chemically or with light, otherwise solidified.

  The lens of the present invention may include two layers, three layers, or multiple layers. In some embodiments of the invention, the generally constant refractive index layer provides either the back or front surface of the lens. The back or front is made according to the patient's prescription. In some embodiments of the invention, a reverse index gradient profile is used for adjacent plus and minus power layers to efficiently increase or double the index difference. This provides a means to achieve high addition with low or flat curvature and minimize lens thickness. At least one set of inverse refractive index gradient portions is required to increase the refractive index.

  For example, if the refractive index gradient profile defines a maximum refractive index difference of 0.3, 2) a reverse refractive index gradient layer (the high refractive index portion includes the upper part of the distance vision portion of the adjacent minus power layer) 1) in combination with 1) the refractive index gradient layer (the high refractive index part includes the lower part of the near vision part of the plus power layer), the effective refractive index difference is 0. Doubled to 6. This very large index difference is advantageously used in accordance with the present invention to provide a high diopter (power) progressive add power in thin lens designs.

  In another embodiment of the invention, the lens consists of a number of thin layers alternating with a number of refractive index gradient layers having inverse profiles and inverse power values. For example, a 50 mm diameter compound lens that provides an add power of 2.5 diopters may include 13 low curvature layers having a critical thickness as high as 0.22 mm. On the other hand, the thickness of the entire lens may be close to that of a standard lens having a similar addition power. A plus power layer with an increase in refractive index and a positive power in one direction (0.22 mm in center thickness) is a negative power increase in the opposite direction (0.22 mm in edge thickness) in the opposite direction. Alternating with adjacent negative power layers. Thereby producing a plano power lens or a lens with a flat power window of 1.5 mm thickness.

  However, it is actually a progressive lens with a sufficient addition power. By using a plurality of refractive index gradient layers alternately stacked in this manner, an effective refractive index difference is obtained as described above. Since each layer is very thin and may be processed continuously or independently, manufacturing methods that provide good mixing results are advantageously utilized when thin parts (layers) are manufactured. For example, the spraying method described above is desirable to provide a thin film of refractive index gradient composition. While it is desirable to be able to spray thin parts (layers), this is not always possible. This is because the density of one resin or monomer may be greater than the density of the other resin or monomer. As a result, one resin is slid under the other resin due to the influence of gravity.

  This problem can be solved by limiting the amount of material applied and the time at which spray application ends when the densities are substantially different. Each layer may be fully or partially cured or polymerized after application and prior to application of the next layer. If the substrate surface to which the spray is applied contains a material having the desired bending properties, the shape of the substrate surface can be changed by using a small amount of such a material. That amount is the amount needed to produce the necessary uneven curvature required to give the gel or partially polymerized layer the correct radius.

  There may be other reasons for limiting the thickness of the applied layer. For example, some photopolymerization processes or materials provide suitable results only for a limited depth of resin or monomer. Other processes designed to change the refractive index of the polymer (eg, electron beam irradiation or chemical treatment with penetrating reactive diluents or swelling agents) are suitable results for relatively thin parts (layers) Or may provide suitable results only for limited penetration depths. Thus, independent or sequential processing of very thin adjacent layers as described above may be achieved by these means.

  In another embodiment of the present invention, the gradient index progressive lens takes the form of a doublet Frennel lens that includes one or two gradient index layers. The surface of the Furnell lens includes a number of discontinuous coaxial (concentric) annular portions. The coaxial annular portions each define a slope corresponding to a continuous lens surface shape and are collapsed to form a lower profile surface. Each adjacent optically functional annular section has a non-optically functional step (a non-optionally functional step), and each step is also annulus. It is in the form of an (annular band). These steps, along with a number of refractive surfaces, determine the overall shape and lens thickness of the lens.

  High plus / minus power Frunnel lenses are manufactured at a ratio (ratio) of conventional lens thickness (many with a maximum step height of less than 0.26 mm). By making the refractive index gradient layer thick enough to fill the open area of the short focus Furnell surface (eg, 0.3-0.4 mm thick), the progressive lens of the present invention is extremely simple Obtained with a thin lens configuration. Here again, the spray technique described above provides an ideal method of applying a gradient index layer (thickness of 0.3-0.4 mm). The use of the two new Furnell lenses of the present invention provides improved efficiency and effectiveness.

  The lenses of the present invention are designed in a number of typical lens shapes or forms that utilize either spherical or aspheric curvature. Shape or structure refers to the overall contour of the lens. That is, whether the front and back surfaces are flatter (having a low value base curve) or more curved (having a high value base curve). By using spherical surfaces in a wide range of lens structures (molds and shapes), excellent optical properties can be obtained. Of these lens structures, certain structures (types, shapes) provide improved properties over other structures.

  Generally speaking, the lens form is usually considered to be greatly curved for spectacle lens applications. The lens shape tends to produce less astigmatism and perform better astigmatism at standard eyeglass lens distances from the eye than shapes that are not largely curved. In the case of a spherical lens design that incorporates a plus or minus power that satisfies the patient's prescription, the matter corresponding to the shape provides the best properties. Instead, aberrations are minimized by using an appropriate conic constant to aspheric designs that require slight astigmatism correction. And the wide range of base curves and the optical properties of the prescription are optimized. This broadens the choice of lens shape and allows for a flatter base curve that can be used without compromising optical properties.

  For those lenses that require large aberration correction at high conic constant values, a reduction in distortion or a non-uniformity of magnification in the larger power parts of the lens may be achieved. Slight aspheric overcorrection with high conic constant values or additional aspheric conditions can be used to further reduce the lens thickness of the desired lens. Alternatively, it is used to change the magnification characteristic of a desired lens.

  Other features and advantages of the present invention will become apparent from the following detailed description of the invention, when taken in conjunction with the accompanying drawings.

FIGS. 1A, 1B, and 1C are side views schematically showing a first group (embodiment) of a refractive index gradient type progressive lens. These refractive index gradient type progressive lenses include a single refractive index gradient layer in a doublet lens configuration including a concave inner surface, a flat inner surface, and a convex inner surface. FIG. 2 is a graph of various refractive index gradient profiles. 3 (a), 3 (b), and 3 (c) are diagrams schematically illustrating a resin casting chamber including a dissolvable membrane for separating a resin portion. FIG. 4 is a diagram showing a table of lens parameters of the lenses schematically shown in FIGS. 1 (a), 1 (b), and 1 (c). FIG. 5 is a chart showing the relationship value of the lens radius between the addition power (add power) and the refractive index difference of the lens. FIG. 6 is a graph plotting the front and back curvatures against the inner curvature of the gradient index lens. 7 (a), 7 (b), 7 (c), and 7 (d) are diagrams schematically showing different orientation angles of the refractive index gradient lens layer. FIG. 8 is a side view schematically showing a second group (embodiment) of the refractive index gradient type progressive lens. The refractive index gradient type progressive lens includes one refractive index gradient layer having a minus power in a doublet lens configuration including a concave inner surface. FIG. 9 is a side view schematically showing a third group (embodiment) of the gradient index type progressive lens. The refractive index gradient type progressive lens includes one refractive index gradient layer at the rear in a doublet lens structure including a concave inner surface. FIGS. 10A, 10B, and 10C are side views schematically showing a fourth group (embodiment) of the refractive index gradient type progressive lens. Each of these refractive index gradient type progressive lenses includes one refractive index gradient layer at the rear part in a doublet lens structure including a concave inner surface, a flat inner surface, and a convex inner surface. FIGS. 11A and 11B are side views schematically showing a fifth group (embodiment) of the refractive index gradient type progressive lens. These refractive index gradient type progressive lenses have a doublet lens structure including layers of plus and minus degrees at both the front and rear positions, and include two refractive index gradient layers. FIGS. 12A and 12B are side views schematically showing a sixth group (embodiment) of the refractive index gradient type progressive lens. These gradient index progressive lenses include two gradient index layers in a triplet lens configuration. The triplet lens configuration includes a plus power layer, a minus power layer, and a third layer. The plus and minus power layers are located at both the front and back of the lens, and the third layer is both the front (FIG. 12 (b)) and back (FIG. 12 (a)) of the lens. The patient has a prescription and thus the obtained surface in the position. FIG. 13 is a side view showing a refractive index gradient type progressive lens. The refractive index gradient type progressive lens includes a refractive index gradient in the form of a doublet Flannel lens. The arrows ◯ and Δ in FIG. 13 are connected to the arrows ◯ and Δ in FIG. 14, respectively. FIG. 14 is an enlarged view showing an optical path passing through a peripheral region of the Fullel lens of FIG. The circles ○ and Δ in FIG. 14 are connected to the arrows ○ and Δ in FIG. 13, respectively. FIG. 15 is a side view showing a refractive index gradient type progressive lens. The refractive index gradient type progressive lens includes a refractive index gradient in the form of an optimized doublet fullnel lens. The circles ○ and Δ in FIG. 15 are connected to the arrows ○ and Δ in FIG. 16, respectively. FIG. 16 is an enlarged view showing an optical path passing through a peripheral region of the Furnell lens shown in FIG. The circles ○ and Δ in FIG. 16 are connected to the arrows ○ and Δ in FIG. 15, respectively. FIG. 17 is a side view showing a refractive index gradient type progressive lens. The refractive index gradient type progressive lens includes a refractive index gradient in the form of an optimized triplet fullnel lens. The shape of the lens is curved like the patient's eye. FIG. 18A is a side view showing a refractive index gradient type progressive lens. The refractive index gradient type progressive lens includes a refractive index gradient in the form of an optimized doublet fullnel lens. The shape of the Furnell lens is curved like the patient's eye. FIG. 18B shows the lens of FIG. 18A having a protective layer. FIG. 19 is a diagram showing a gradient rate portion obtained by creating a common region of deposits by spraying. FIG. 20 is a side view schematically showing a 14-layer gradient index progressive lens having a large number of gradient index layers. FIG. 21 is a diagram showing an apparatus used to make a refractive index gradient type progressive lens layer by a spray technique. FIG. 22 is a diagram showing a mixed state of two liquids by particles descending through an interface separating the liquids.

  The following description will be made so that the lens of the invention described in the claims can be manufactured and used. It includes the best mode in which the inventor knows the invention as of the filing date.

  1 (a), 1 (b), and 1 (c) show the configuration of three doublet lenses of the lens of the first embodiment configured according to the detailed description. 1 (a), 1 (b) and 1 (c) show three possible lens shapes. The front lens part A has a refractive index gradient (gradient refractive index) layer, and the rear lens part B has a generally constant refractive index layer of the lens. The front lens part A defines the front position of the lens and the position far from the eyes, and the rear lens part B defines the rear position of the lens and the position close to the eyes. The front lens part A has a positive power and the rear lens part B has a negative power. In the present embodiment, the refractive index increases from the far vision portion to the near vision portion through the progressive intermediate vision portion of the lens. Therefore, the frequencies of intermediate visual acuity and near visual acuity gradually increase.

  FIG. 1A shows an embodiment in which the internal curved interface R2 is concave with respect to the front lens part A. FIG. FIG. 1B shows an embodiment of a lens in which the internal curved interface is a plane. FIG. 1C shows a lens embodiment in which the internal curved interface is convex with respect to the front lens part A. FIG. FIG. 1A is used to describe the surfaces and layers shown in the three figures (FIGS. 1A to 1C), and FIGS. 1B and 1C are refractive index gradients ( It is used to describe the position and range of (gradient refractive index).

  The lens layer A (front lens portion A) is made of an optically transparent material having a variable refractive index value. A1 corresponds to the distance vision portion of the lens, A2 corresponds to the progressive intermediate vision portion of the lens, and A3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion A2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part A1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part A3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision portion A2 is a low refractive index value equal to the low refractive index value of the refractive index N1 of the far vision portion A1 adjacent to the progressive intermediate vision portion A2, and is close to the progressive intermediate vision portion A2. It increases to a high refractive index value equal to the high refractive index value of the refractive index N3 of the visual acuity part A3. The gradient profile has a regular and continuous rate.

The ratio is generally characterized over its range (degree, breadth) to correspond to the position of π / 2 to 3π / 2 of a sine wave curve or a sine wave curve. Yes. The rear lens part B is made of an optically transparent material. The refractive index N4 of the substance is generally constant and does not change. The front surface 4 of the front lens portion A has a convex curvature (curvature) having a radius value R1. The internal interface I has a curvature (internal curvature interface) R2.
The rear surface 5 of the rear lens part B has a concave curvature with a radius value R3. In this embodiment, the following embodiments and examples, each lens part is manufactured as a preform and bonded using an optical bonding agent. Subsequent layers may be bonded and cast to the surface of the preform portion layer. The preform is formed prior to the casting or cementing of the lens part and means a solid or semi-solid shape. The lens part of the preform is manufactured by thermoforming, molding, grinding (grinding), casting or other processes.

  The following quadratic equation may be used to define the sinusoidal shape described above.

Formula 1

Sinf (x) = ax2 + bx + c
(Where, a denotes the value selected between 2.0 to-2.0, b represents a 1- (2aπ), c represents the a * 3π ^∧ 2/4.)

  The value of “a” is used to define various curves. The x and y coordinates of the curve correspond to the instantaneous refractive index of the refractive index layer at successive points along the range of the gradient portion.

FIG. 2 shows a graph showing five curved curves based on the above equation. The refractive index against Y is plotted. Y is the distance (in millimeters) of the progressive intermediate vision portion of the lens between the broken line 2 and the broken line 3 shown below the lens center line CL shown in FIGS. 1 (b) and 1 (c). For example, the value of “a” is selected as −0.3, 0, 0.1, 0.3, 0.4. An a value of “0” defines a sinusoidal waveform and is considered as a standard for the lens of the present invention. This is because it shows the ratio of equal increase and decrease (increase / decrease) in the refractive index. This is the case when the upper and lower parts of the sine wave are the targets. In some instances, it is preferable to use a sinusoidal curve that is changed to non-target. The change in curvature at the two extremes is zero.

  For example, it is desired that the progressive addition be introduced at the junction of A1 and A2 with a sudden change, while the progressive addition is introduced at the junction of A2 and A3 with a mild change. When, the rate of change of the refractive index is required as shown in the curve where a is -0.3. Conversely, in other situations, the progressive addition is introduced into the junction between A1 and A2 with a moderate change, while the progressive addition is introduced into the junction between A2 and A3 with a sudden change. When desired (as is likely to happen in the case of short Y distances), the moderate rate of change of the refractive index between A1 and A2 is as shown in the curve where a is 0.4 Needed.

  In general, the value of “a” is preferably a positive value rather than a negative value. This is because the boundary from far vision to progressive intermediate vision experienced by a patient viewing a lens with a plus “a” value is no problem. Also, if “a” is a positive value, it is slightly larger (very much) to provide a small amount of add power compared to a lens where “a” is equal to or minus “0”. slightly greater) is required. It is more important to use a positive value of “a” when the progressive intermediate vision portion of the lens is about 10 mm or less. This is because, as the viewer's gaze direction moves from the far vision portion of the lens to the progressive intermediate vision portion of the lens, a sudden refractive power (power) change causes visual disturbance.

  Furthermore, the difference in object focal length between objects seen through the lower part of A2 (eg, 16 ″ versus 15.75 ″) relative to the upper part of A3 is small, and the upper part of A2 (eg, The difference in object focal length between objects viewed through finite (17 ') with respect to infinity is large. Thus, the small percentage of refractive index change located at the junction of A1 and A2 provides a more gentle visual change for the progressive intermediate vision portion of the lens. The effect achieved is similar to the effect of a low addition progressive lens in terms of visual “comfort” while providing high diopter addition in the near vision portion of the lens.

  The sine wave model of the refractive index gradient described above has a refractive index profile. The refractive index profile is large from a low refractive index value equal to the low refractive index value of the adjacent portion (distant vision portion) having a low refractive index to a high refractive index of the opposite adjacent portion (near vision portion) having a high refractive index. Become. Such gradient rate profiles are manufactured using a number of different processing methods. Interdiffusion of two monomers at the liquid interface is one way to provide a refractive index gradient with different values of high refractive index.

  Also, diffusion of one monomer among partially polymerized monomers or gelled monomers having different refractive indices is one method for providing a refractive index gradient having different values of high refractive index. It is. Mutual solubility or miscibility and interdiffusion penetration of low viscosity monomers in high viscosity gelled “prepolymers” are a combination of heat and duration factors that determine diffusion and refractive index gradient depth. ).

  These approaches can be suitably performed with recently developed optical monomers and resins having high refractive index values suitable for use in ophthalmic lenses, as described above. For example, materials including disulfides, thiols, polythiols or polyisocyanate compounds and some epoxies provide a refractive index between 1.65 and 1.78. Other resins, including many methacrylate or fluorin polymers and fluoropolymers, have refractive index values of 1.36 or less. They are then suitable for use with compatible high refractive index materials in spraying or diffusion processes.

  There is the fact that slight perturbations or irregularities at the liquid interface of the two monomers or resins used in the diffusion process lead to unwanted properties or deformations in the final refractive index profile (first problem). Because of that fact, it is very important whether the interface is regular or has a favorable profile. The interface includes a meniscus that typically forms along the upper surface of the liquid in a container (eg, a lens molding chamber or mold used in the diffusion / molding process). In particular, if the viscosity of the liquid optical resin is high, the meniscus formed at the boundary between the lens chamber and the resin is greatly curved.

  Further, when the internal dimension of the lens molding container is small, the meniscus is continuous across the interface. And of course, when the material is partially polymerized to the gel state, the meniscus remains in that state. Whatever process is used to create the refractive index gradient, the interface generally has a planar dimension perpendicular to the length of the interface, i.e., through the lens, planar, cylindrical, elliptical non- It has a spherical shape (rugby ball shape), a conical shape, and the like.

  Another similar problem (second problem) relates to the application of another liquid monomer next to or on top of one liquid monomer and how to preserve the integrity of the interface during application. . Here, the use of a removable separator or barrier is proposed. However, minor disturbances at the interface may be caused by the movement of the separator. In particular, when the separator is lifted from the liquid, the changing refractive index profile is detrimental. Both problems (first and second problems) are solved by utilizing a new diffusion method that involves the use of a polymer membrane that can be dissolved as a separator in the molding chamber.

  Both (two) resins come into contact with the separation membrane and dissolve the membrane with one or both resins. Then, mutual diffusion or diffusion of one resin in the other resin occurs, and subsequently, polymerization or curing of the resin composite mixture proceeds. The membrane should be thick enough to withstand the weight or pressure of the first resin introduced prior to the introduction of the second resin into the chamber section. However, the membrane should be thin enough to dissolve within the desired time (eg, within an hour). A 0.012-0.025 mm thick polymethylmethacrylate film membrane provides the desired attributes. Copolymer membranes having a refractive index such as an intermediate (average) value or a variable value between the refractive index of the high refractive index resin and the refractive index of the low refractive index resin may be used.

  FIG. 3 shows a molding chamber for an instantaneous refractive index gradient type progressive lens. The molding chamber includes a dissolvable membrane M1 sandwiched between vertical lens chamber portions S1 and S2. The lens chamber portion S1 corresponds to the distance vision portion A1 of the lens, and the lens chamber portion S2 corresponds to the near vision portion A2 of the lens. The lens chamber portion S1 is filled with one refractive index resin supplied from the port P1. On the other hand, the lens chamber portion S2 is filled with the other refractive index resin supplied from the port P2.

  Only when the resin in the lower part S2 (lens chamber part S2) is polymerized in a gel form before the membrane is dissolved, the density may be smaller than that of the resin in the upper part S1 (lens chamber part S1). . Otherwise, once the membrane is dissolved, a high density resin is contained in the lower part S2 to avoid unnecessary mixing and re-stabilization of the liquid resin. If both resins have the same density, either is located in the upper part S1 or the lower part S2. Furthermore, the upper part S1 and the lower part S2 may be positioned side by side. During the filling process or near the end of the filling process, the molding chamber may be tilted to allow air bubbles to escape from ports P1 and P2.

  Once the lens chamber portions S1, S2 are filled with resin, the membrane is dissolved in one or both resins by the time the diffusion process begins. After the required diffusion has begun, the desired gradient profile is created and the lens resin is fully polymerized by either photopolymerization or catalytic polymerization. Similarly, in FIG. 3 (b), a cylindrically curved membrane is used to obtain a curved interface. The curved membrane M2 is sandwiched between a lens chamber portion S3 that manufactures the refractive index resin portion N1 and a lens chamber portion S4 that manufactures the refractive index resin portion N2.

  Although not shown, the membrane may be swung forward or backward to obtain a tilted refractive index orientation angle. In such cases, the molding chamber may be tilted at the same tilt angle during the diffusion and polymerization processes to ensure an interface that maintains the desired tilt angle. The resin may be filled into a tilted molding chamber as described above to allow air bubbles to escape from the ports P1, P2. Further, the chamber of FIG. 3 (b) is configured as shown in FIG. 3 (c) so that the remaining bubbles do not remain in the central region of the concave portion of the membrane M2 (which faces downward of FIG. 3 (b)). Alternatively, it may be used upside down. Thereby, the remaining bubbles rise upward on the left and right sides of the molding chamber along the curvature of the membrane, and go to the filling ports P3 and P4. These areas are outside the optical part of the lens.

  A further way to facilitate and speed up the production of refractive index blends involves the controlled mixing of different refractive index resin or monomer solutions in a container or molding chamber (eg, a membrane-containing molding chamber as described above). . In order to achieve this purpose, resin liquids (having different refractive indexes) constituting two or more layers adjacent to each other in the vertical direction or another adjacent layer are dispersed in fine particles dispersed in the uppermost layer solution (for example, , Glass beads) at the interface of those layers.

  FIG. 22 is a diagram schematically showing this process using molding chambers arranged in the vertical direction. In FIG. 22, the particles P (not enlarged) begin to descend from the upper liquid in the upper part of the lens chamber part S1 towards the interface I (indicated by the dotted line in the middle of the molding chamber) and through the interface I. As shown. The particles P are shown to be concentrated on top of the upper layer solution (liquid in the lens chamber portion S1). However, they are evenly distributed throughout the upper liquid. In any case, the particles P slowly settle from the upper liquid via the interface I.

  The particles settle into the lower layer solution (via the lower layer solution in the case of multiple layers) by gravity or centrifugal force. And in doing so, it forms a blend zone below the initial interface level. The diameter of the particles can be, for example, up to 50 microns with the particles concentrated. Similarly, the particle size may be selected to control the range of the blend. Although the use of particles is illustrated in connection with lens formation having two refractive indices joined by a blend, the use of particles is shown and described in connection with FIGS. 3 (b), 3 (c). It is implemented in a number of blends in conjunction with lens making technology.

  The forces and fields used to move particles through a layer of solution are not only gravity and centrifugal forces. For charged or magnetic particles, electric and / or magnetic fields may be used. However, particles that fall off and settle out of the upper layer solution attract a small amount of particles of the upper layer solution through the interface to the adjacent lower layer solution. As the particles pass through the liquid, the single component resin coating is cleaned. The particles not only carry the resin from the upper layer solution to the adjacent lower layer solution, but also finely mix the solution in the region through which the particles pass. As noted above, this method may be used in a molding chamber or a molding chamber that includes or does not include the membrane system described above. The process may be performed in a mold arrangement (layered resin solutions are arranged side by side). And in that arrangement, a field other than gravity is required to provide lateral movement of the particles from one adjacent solution to the other.

  According to the present invention, the positions of the broken lines 2 and 3 shown in FIGS. 1 (b) and 1 (c) may change significantly in the Y direction shown in FIG. 1 (a). As shown in FIG. 1B, the broken line 2 is located 2 mm below the center line CL. The broken line 3 is located 18 mm below the broken line 2. Thereby, a progressive intermediate vision portion is provided in which the length between the lower portion of the far vision portion and the upper portion of the near vision portion is 18 mm. On the other hand, for example, as shown in FIG. 1C, the broken line 2 is located 3 mm below the center line CL. The broken line 3 is located 10 mm below the broken line 2. Thereby, a progressive intermediate vision portion is provided in which the length between the lower portion of the far vision portion and the upper portion of the near vision portion is 10 mm.

  The extent of the progressive intermediate vision portion of the lens is smaller than the range typically provided with an aspheric progressive lens without degrading the astigmatism typical of aspheric progressive designs. This particular property is shown as a significant advantage of the gradient rate design taught by this disclosure over the design of an aspheric progressive lens. So-called “soft” lenses as taught by this disclosure are achieved when the Y range of the progressive intermediate vision portion is increased (version having a length of 18 mm).

  On the other hand, the so-called “hard” design is achieved when the Y range of the progressive intermediate vision portion is reduced (version with a length of 10 mm). As described above, the gradient profile follows the rate of change (rate of change). The rate of change is regular and continuous and is generally characterized over a range corresponding to the position of π / 2 to 3π / 2 of a sine wave curve or a sine wave curve. . Therefore, there is no discontinuity that is anxious from near vision through distant vision through progressive intermediate vision.

  FIG. 4 is a table showing related values of the spherical curvatures R1, R2, and R3. It shows an example of a lens schematically depicted in FIGS. 1 (a), 1 (b), and 1 (c). Each lens 1-7 has a constant edge thickness of 0.05 mm of the front lens part A and a constant center thickness of 0.25 mm of the rear lens part B. These lenses, as shown in the table, have total lens center thicknesses and front lens edge thicknesses that are slightly different for the lenses of the examples (lenses # 1 to # 7).

  The two columns from the right in the table of FIG. 4 show the conic constant value and additional information of the aspheric type of each embodiment. In FIG. 4 and all subsequent lens embodiments, the conic constant CC is shown with radius R, center thickness CT (mm) and edge thickness ET (mm). The conic constant value is shown together with the front (a) and the rear (p) showing the lens surface. Radius, center thickness and edge thickness values are only relevant for spherical lenses.

  Lenses 1-7 provide '0' diopter power in the distance vision portion of the lens and 2.5 diopters addition in the near vision portion of the lens. The add power of this lens and all other add powers are units of diopters and are calculated as 1000 / effective focal length. The selection of “0” power in the distance vision portion of the lens represents the standard for distance vision responsible for normal vision. It is calculated to be at least equal to the effective focal length of +/− 1e + 009. When the lens of the present invention is processed according to the patient's prescription, modifications such as laboratory work are required.

  However, since some prescription values are units of diopters that deviate from normal vision, the “0” power base standard corresponding to normal vision is retained in all calculations in this specification. All radius and power calculations are based on the refractive index nd calculated with helium d-line (587.56 mm). Alteration (processing) of the surface 5 according to the patient's prescription requires or provides other functions. Other functions modify both the distance vision power and the near vision power, but do not change the addition power provided by the lens. These lenses have the following additional refractive index parameters:

Formula 2

N1 = 1.46
N2 = 1.46-1.7 gradient N3 = 1.7
N4 = 1.58

  As described above, additional constants regarding the relationship of R1, R2, and R3 over the full range of possible lens shapes with respect to refractive index, add power, lens layer thickness, and distance vision “0” power are shown in FIG. It is done. As shown in FIG. 4, the additional constant is expressed as a curvature relationship and a performance number or CREN. CREN is a numerical value that defines the relationship between the radii of both surfaces of a lens constructed in accordance with this disclosure. It is expressed in units of diopters based on the “0” frequency standard described above. CREN also represents the “gross sag” of a fully curved convex feature diopter or lens. In all cases, the CREN value is a positive value, which is larger than the addition power of the lens. Each lens constructed according to this disclosure is defined by a CREN number (value). The CREN values for all subsequent lens embodiments are then expressed along with other parameters that define the lens parameters.

  It is a property of the lens made by this disclosure that each lens requires an additional bulk or “convex surface” to provide add power due to refractive index changes associated with the subject rotating surface. Furthermore, the increased plus power of the lens layer A required to obtain a power difference or addition between the distance vision portion and the near vision portion of the lens is the distance of the lens by the lens layer B having a minus power. In the vision section, it must be reduced to the patient's prescription value or reference “0” frequency. Thus, the “gross sag” of the lens is further increased. The CREN number (value) is between 40 and 50 (with the highest efficiency and the smallest volume) for lenses with 1-3.5 diopters addition (when efficiency is lowest and volume is highest) And fluctuate between about 3-11 with the same addition. Such high efficiency values provide a minimum thickness lens. The CREN value is calculated by the following formula.

Formula 3

1000 / R1 + 2 (1000 / R2) + 1000 / R3 = CREN
(However, R1 represents plus when convex, and minus when concave, R3 represents plus when concave, minus when convex, and R2 is plus when the curvature is convex with respect to the lens portion A. When the curvature is concave with respect to the lens part A, it represents minus.)

  For lenses that incorporate other powers other than “0” in the distance vision part of the lens, the CREN value is determined by first canceling the add power or prescription value and calculating. May be. It is most desirable that a lens having a low CREN value has the smallest lens bulk and critical thickness. When the refractive index difference (RID) between the upper and lower side surfaces of the lens is the smallest (approximately 0.08 to 0.16 as shown at the top of the table), the CREN number (value) is the highest. When the RID becomes the largest (about 0.60 or more as shown in the lower part of the table), the CREN number (value) is the lowest. Medium and high RID values use both an optical resin component with a very high refractive index and an optical resin component with a very low refractive index together to create a refractive index gradient profile for the front lens part A Can be obtained.

  The lens of this embodiment has an RID value of 0.24 (1.7-1.46 = 0.24). The two substance components selected as the material of the gradient index layer have a relatively high refractive index value or a relatively low refractive index value than those of the lens example. However, they produce the same RID value and the calculated values of R1 and R2 are substantially the same except for R3. Therefore, the calculated CREN value is different from the refractive index at which the refractive index of the rear lens portion B does not change. By adjusting the refractive index of the rear lens part B in the corresponding direction, the same value of R3 and CREN value is created. Nevertheless, the refractive index of the lens layer B should be high in order to achieve low CREN values and excellent optical properties. A high RID value is obtained using an optical resin component having a large refractive index difference.

  For example, an RID value of 0.32 is obtained using a low refractive index resin component of 1.42 along with a high refractive index component of 1.74 to create a refractive index gradient profile. The RID value of the lens is increased by a factor of 2 according to the method taught by this disclosure. That is, the means described in the fifth embodiment is increased to the maximum value (for example, 0.64) of the refractive index difference between the two resin components.

  FIG. 5 is a table showing CREN values of the lens of the first embodiment according to the RID of the gradient refractive index layer and the addition power of the lens. The refractive index values for all calculations are the values described above in relation to FIG. The addition powers in the table range from 1 to 3.5 diopters. The CREN number (value) of the lens of the above example having the same parameters except for the shape of the lens varies in the range of 18.436 to 18.729. The CREN number (value) defines the main part of 18.07-19.10 shown in the category at the intersection of the aforementioned RID of 0.24 and the addition of 2.5 diopters.

  Its range of categories on the chart has been expanded to 2% beyond the numerical range of the example lenses of 18.07-19.10 to include additional lens shapes not included in FIG. Similarly, the range of other categories in FIG. 5 has been expanded to 2%. The CREN value range of 18.07-19.10 indicates a group of lenses that are particularly suitable for use (albeit at intermediate efficiency) among refractive index gradient lenses made in accordance with the disclosure of the present application. .

  As can be seen from the table, the low CREN number range (representing the most efficient design) is located where the power addition is the smallest and the RID value is the largest. Low add power requires a small refractive index change, as small curvature changes are required in aspheric progressive lenses. The most efficient CREN category (3.05 to 3.19) in the chart of FIG. 5 is approximately 3 diopters bulk or “gross sag” to provide 1 diopter recruitment. Design the total amount of. When the CREN value is high, the curvature (R1 and R3) is steep when the volume (bulk) is large, even if it has a convex internal interface radius. Thus, there are useful form limitations for high CREN values.

  For example, even if the inner convex interface R2 has a steep radius of curvature of 105.809 mm, a 3.5 diopter power lens (add lens) having 0.16 RID and a CREN value of 41.18 is The curvature is fairly steep on both the front and rear surfaces. That is, the convex surface R1 has a curvature of 80.0 mm at the front surface portion, and the concave surface R3 has a curvature of −102.242 mm at the rear surface portion. The internal convex interface R2 has a curvature of −400 mm and the same 3.5 diopter lens (add lens) having the same RID value of 0.16 as in the above example has a convex surface R1 curvature of 42.739 mm, and −46. It has a concave R3 curvature of 144 mm and a CREN value of 40.07.

  Such a steep lens has better optical properties compared to a lens with a convex R1 curvature of 80.0 mm, but from a decorative point of view such a large curved lens is not preferred. It seems to be. Nevertheless, the range of each CREN value in FIG. 5 is calculated from the range of the lens shape including the steep type as described above. More than 50 CREN categories representing highly inefficient designs are not included in this chart because lenses with these CREN values have limited application in terms of their thickness, weight, and high curvature.

  The table also shows the near maximum RID of the first layer of refractive index gradient, or the maximum RID of the lens if only one lens layer contains a refractive index gradient. The demarcation located at the 0.32 RID level is based on the use of an effective compatible optical resin having both a very high refractive index and a very low refractive index. Other materials with both high and low refractive indices are used to obtain large RIDs. In such cases, the potential CREN value may be low. As mentioned above, it is possible to use two index gradient profiles in the opposite direction to increase RID and decrease CREN values. In such cases, values beyond the first line and up to "approximate maximum RID of the lens" can be applied.

  Instead, two reverse gradient index (refractive index gradient) layers are made of a material with a more appropriate index of refraction so that each RID value is smaller than the RID value of lens layer A in the lens of FIG. Sometimes the additional RID may exceed the RID of a lens with only one gradient index layer with the largest RID. This produces a very effective and thin lens. As described above, various constants including refractive index, RID, addition power, constant edge thickness (0.05 mm) of the lens layer A, and constant center thickness (0.25 mm) with respect to the lens layer B are set. The lens family can have various shapes defined by specific relationships between R1, R2, and R3 calculated as CREN values.

  Thus, when having different base curves and lens shapes, R2 must be a special value to obtain the reference “0” power and add power specified via the distance vision portion of the lens. From FIGS. 1 (a), 1 (b), 1 (c), and FIG. 4, R2 has a flat convex surface R1 curvature and a concave surface R3 curvature (relative to the lens layer A) over a range of possible lens shapes. ) By exhibiting curvature in a more convex direction and in a more concave direction (relative to the lens layer A) with steep convex R1 and concave R3 curvatures, typically R1 Matches (corresponds) to R3.

  FIG. 6 is a graph showing a relationship of plotting the diopters of the curvatures of R1 and R3 against the range of the diopter values of R2. The graph plots an example of the CREN family of lenses of FIG. 4 where the internal interface R2 has curvatures of an internal convex interface, an internal flat interface, and an internal concave interface. The graph then satisfies the CREN value equation described above. The equation converted to surface diopter is shown below.

Formula 4

  D1 + 2 ・ D2 + D3 = CREN

  Furthermore, the unique and specific properties of lenses made according to this disclosure are described. Of course, when the refractive index values N1, N2, N3 and N4 are different from the refractive index of the example lens, the correlated values shown will change.

  The superior optical properties described above are obtained using a spherical surface over a wide range of shapes. In this case, a lens with a highly curved surface tends to obtain slight astigmatism and good focus. The size of the conic constant value shown in FIG. 4 indicates the degree to which correction is required. The size also indicates which example lens designs work better with little or no asphericity. As is apparent from FIG. 4, the example lens (example lens) # 7 has the highest CREN value and the flattest curvature values of R1 and R3, and has a theoretical conicity of -14.879. The largest correction amount calculated as a numerical value is required.

  Conversely, for example, steep lens # 1 with the smallest CREN value requires almost no correction. Correction of lenses made in accordance with this disclosure with aspheric curvature, as a power, cannot provide optimal visualization for all lens parts. Therefore, it should be noted that the correction amount varies over the entire lens.

  Generally speaking, little correction is required on the top of the distance vision portion of the lens, regardless of its shape. As such, a conic constant value that is smaller than the conical constant value listed for planar lenses is selected such that some correction is achieved without loss of optical properties in the distance vision portion of the lens. Slightly steep lens shapes that require a slight aspheric correction may provide an alternative lens when decorative appeal with planar lenses is not the primary concern. In the extractable lens shown in FIG. 4, for example, it can be an excellent alternative lens to the lens # 6 lens # 7.

  Since there is no single (common) radius value for an aspheric surface that can be used to accurately calculate the CREN value, it is not possible to use the most suitable sphere for each aspheric surface (the best-fit sphere) instead. Provide a more accurate calculation of the CREN number (value). The radius of the best-fit spherical surface of a lens having a negative conic constant value is always slightly more curved than the apical radius of the cone. Therefore, the calculated CREN value is low. For example, using the best fit spherical radius of 195.1687 mm instead of the aspheric curvature vertex radius of lens (# 7) (not shown in FIG. 4), the recalculated CREN number is 18.419. is there. By comparison, this value is close to the CREN value of lens # 1 and requires little correction.

  All the recalculated CREN numbers obtained using the aspheric best fit spherical counterparts of lenses # 1 to # 7 are shown in the table of FIG. As can be seen from the table in FIG. 4, the CREN values of all the best-fit spherical surfaces are close to each other and close to the CREN value of lens # 1. It may be practically optimal in terms of not requiring aspheric correction. Thus, it can be said that a narrow CREN range defines a family of lens shapes that share common optical attributes. Nevertheless, rather than a narrower range as shown in FIG. 4, a wider CREN range as described above is shown in the table of FIG. 5 when an uncorrected spherical lens is utilized.

  7 (a), 7 (b), 7 (c), and 7 (d) show four versions of the lens of the first embodiment according to this disclosure. 7 (a) to 7 (d), the orientation angle X of the refractive index gradient is different. A refractive index gradient orientation angle refers to an angle that defines at least a portion of a surface (eg, a plane). This plane intersects a refractive index gradient that is a substantially constant refractive index. By properly selecting the orientation angle of the refractive index gradient, the vision through the refractive index gradient of the lens at a specific gaze angle of the patient (represented by the line CO in the figure) can be optimized, There is no blur. The aberrations and blurring result when the patient's point of view through the gradient is tilted at an angle where the refractive index is not constant. That is, such aberration and blurring occur when the orientation angle is different from “0” or the gaze angle, as shown in FIG.

  There are two ways to obtain an orientation angle that is close to or equal to the patient's gaze angle when viewed through the refractive index gradient region of the lens. The first method is to tilt the lens in the spectacle frame with respect to the patient's gaze angle when looking straight forward through the center of the lens. When the positive angle of inclination is about 8 °, as shown in FIG. 7B, the far vision portion at the top of the lens is tilted forward (right side in FIG. 7B) with respect to other areas of the lens. ing. The small tilt not only satisfies the orientation angle criteria for the top of the progressive intermediate vision portion of the lens, but also provides a somewhat improved vision of the object seen through the bottom of the lens. This is because the bundle of rays passing through the eye from the object and the bundle of rays passing through the lens pass at a substantially normal (orthogonal) angle with respect to the surface position through which the bundle of light passes.

  A second method for obtaining a positive gradient index orientation angle is when the patient views a selected region of the progressive intermediate vision portion of the lens, as shown in FIG. Inclining the gradient medium in the gradient factor to approach and respond to the gaze angle. The orientation angle X varies through the progressive intermediate vision portion of the lens so as to more closely correspond to the instantaneous gaze angle through the entire gradient rate portion, as shown in FIG. 7 (d). That is, as shown in FIG. 7D, the orientation angle changes from about 8 ° to 18 °. By combining a constant or variable tilt of the gradient medium with respect to the lens and the forward tilt of the lens, a desired gradient rate orientation angle can be obtained.

  The pupil of the eye is not a point, but rather covers an average area of 4 mm diameter in daytime vision, so visual disturbance resulting from an orientation angle that does not correspond to the patient's gaze angle cannot be completely avoided. However, visual improvement is still achieved by adjusting the gradient rate orientation angle. This is less important when the range of the progressive intermediate vision region is large (about 15-20 mm). However, it is more important when the range of the progressive intermediate vision region is small (about 10-15 mm). As shown in this embodiment, the gradient rate orientation angle is relatively important when the gradient rate portion includes only the plus power portion of the lens (as in this embodiment). In this case, the patient staring straight ahead is looking at the thickest part of the gradient rate part.

  The gradient rate orientation angle is relatively unimportant when the gradient rate part includes only the minus power part of the lens. In such a case, the patient staring straight ahead is looking at the thinnest part of the slope ratio. As described above, an embodiment of a minus power cross slope rate is shown in FIG.

  FIG. 8 shows the structure of a doublet lens according to the second embodiment of the present invention. The front lens portion A includes a gradient index section of the lens, and the rear lens portion B includes a generally constant refractive index portion of the lens. The front lens part A has a negative power and the rear lens part B has a positive power. In the example shown in FIG. 8, the internal curved interface R2 is concave. In this embodiment, the refractive index decreases from the distance vision portion to the near vision portion via the progressive intermediate vision portion of the lens. Therefore, the frequencies of intermediate vision and near vision are gradually increasing.

  The lens layer A in FIG. 8 is composed of an optically transparent material having a variable refractive index value. A1 corresponds to the distance vision portion of the lens, A2 corresponds to the progressive intermediate vision portion of the lens, and A3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion A2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part A1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part A3 having a refractive index of N3.

  The refractive index N2 of the progressive intermediate vision portion A2 is determined from the high refractive index value equal to the high refractive index value of the refractive index N1 of the far vision portion A1 adjacent to the progressive intermediate vision portion A2, and is close to the progressive intermediate vision portion A2. It decreases to a low refractive index value equal to the low refractive index value of the refractive index N3 of the visual acuity part A3. The gradient profile has a regular and continuous rate. As shown by dashed lines 2 and 3, a refractive index orientation angle of 8 ° is obtained by tilting the refractive index medium in the lens body. The range (width) of the refractive index gradient progressive intermediate vision portion located between the broken line 2 and the broken line 3 is 12 mm.

  The rear lens portion B in FIG. 8 is made of an optically transparent material. The refractive index N4 of the material is generally constant. The front surface 4 of the lens layer A has a curvature having a radius value R1. The internal interface I has a curvature R2. The rear surface 5 of the rear lens part B has a curvature having a radius value R3.

  As for the previous embodiment, the values of R1, R2, and R3 are based on a lens that provides 0 degrees in the distance vision portion of the lens and 2.5 diopters addition power in the near vision portion of the lens. . In the lenses of this example and all the following examples, the orientation angle (°) (OA) of the refractive index gradient and the range (IE) (mm) of the progressive intermediate vision portion are the refractive index values (N1 to N1). N4), CREN values, radius values (R1-R3) (mm) and thickness values (CT, ET) (mm). Typical values of parameters of the three refractive index gradient type progressive lenses according to this embodiment are shown below.

  FIG. 9 shows the configuration of the doublet lens according to the third embodiment shown in this detailed description. In FIG. 9, the front lens portion A includes an entire constant refractive index portion of the lens, and the rear lens portion B includes a lens gradient rate portion. The front lens part A has a negative power and the rear lens part B has a positive power. In the provided example, the internal curved interface R2 is concave with respect to the front lens part A. In this embodiment, the refractive index increases from the far vision part to the near vision part via the progressive intermediate vision part of the gradient (rear) lens part B. Therefore, the frequency of intermediate vision and near vision gradually increases.

  As illustrated in the illustrated embodiment described above, the rear lens layer B in FIG. 9 is an optically transparent material having a variable refractive index value, described using a similar convention for identifying and defining lenses. It consists of B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion B2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part B1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part B3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision part B2 is a low refractive index value equal to the low refractive index value of the refractive index N1 of the far vision part B1 adjacent to the progressive intermediate vision part B2, and is close to the progressive intermediate vision part B2. It rises to a high refractive index value equal to the high refractive index value of the refractive index N3 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  The front lens portion A is made of an optically transparent material. The refractive index N4 of the material is generally constant and does not change. The front surface 4 of the lens part A has a curvature having a radius value R1. The internal interface I has a curvature R2. The rear surface 5 of the rear lens part B has a curvature having a radius value R3. As shown by dashed line 2, a refractive index orientation angle (OA) of 8 ° is obtained by tilting the lens with respect to the patient's gaze angle. Both lenses have a 10 mm progressive intermediate vision range (area) (IE).

  The values of R1, R2, and R3 are based on a lens that provides 0 degrees in the distance vision portion of the lens and 2.0 diopters addition power in the near vision portion of the lens.

  FIGS. 10 (a), 10 (b), and 10 (c) illustrate the configuration of three doublet lenses of the fourth embodiment configured in accordance with this disclosure. In these lenses, the front lens portion A includes a generally constant refractive index portion of the lens, and the rear lens portion B includes a lens gradient rate portion. The front lens part A has a positive power and the rear lens part B has a negative power. In this example, the refractive index decreases from the far vision portion to the near vision portion via the progressive intermediate vision portion of the refractive index gradient (rear) lens portion B. Therefore, the frequencies of intermediate vision and near vision are gradually increasing.

  FIG. 10A shows a typical lens in which the internal curved interface R2 is concave. FIG. 10B shows a typical lens in which the internal curved interface is a plane. FIG. 10 (c) shows a typical lens whose internal curved interface is convex. 10 (a) to 10 (c), the rear lens layer (part) B is composed of an optically transparent material having a variable refractive index value.

B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion B2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part B1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part B3 having a refractive index of N3. The refractive index N2 of the progressive intermediate visual acuity part B2 is close to the progressive intermediate vision part B2 from the high refractive index value equal to the high refractive index value of the refractive index N1 of the far vision part B1 adjacent to the progressive intermediate vision part B2. It decreases to a low refractive index value equal to the low refractive index value of the refractive index N3 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  The front lens portion A is made of an optically transparent material. The refractive index N4 of the material is generally constant. The front surface 4 of the lens part A has a curvature having a radius value R1. The internal interface I has a curvature R2. The rear surface 5 of the rear lens part B has a curvature having a radius value R3.

  As shown by broken lines 2 and 3 in FIG. 10 (b), an index orientation angle (OA) of 8 ° is obtained by tilting the lens with respect to the patient's gaze angle. The lens shown in FIG. 10C has an angle obtained by combining the inclination of 4 ° forward of the lens and the inclination of 4 ° of the refractive index medium in the lens. Thereby, a total orientation angle tilt of 8 ° is provided. These lenses have an 8 mm progressive intermediate vision range (area) (IE).

  The correlation values of R1, R2, and R3 represented by the lenses of the examples (fourth embodiment) illustrated in FIGS. 10A, 10B, and 10C are shown in the following table together with the refractive index values. Shown in These lenses provide 0 degrees in the distance vision portion of the lens and 2.5 diopters addition power in the near vision portion of the lens.

  FIGS. 11 (a) and 11 (b) illustrate the configuration of two doublet lenses of the fifth embodiment made in accordance with this disclosure. In these embodiments, only one figure is used to describe the range of possible shapes. It can be seen from the foregoing embodiments and examples that lenses having convex, planar, and concave internal interfaces are described according to this disclosure. In these lenses, both the front lens part A and the rear lens part B include a refractive index gradient part of the lens.

  By using a pair of inverse refractive index gradient layers in adjacent plus and minus power parts, the refractive index difference (RID) of each layer may be additionally combined. The refractive index difference (RID) results in a much better RID value than that achieved by a single index gradient layer. Thereby, as will be seen in the following embodiments and examples, it provides a means for obtaining a high addition with a low curvature or a more planar curvature and reducing the lens thickness.

  In the embodiment shown in FIG. 11A, the front lens part A has a positive power and the rear lens part B has a negative power. The refractive index of the front lens part A increases from the far vision part to the near vision part via its progressive intermediate vision part. Then, the refractive index of the rear lens part B decreases from the far vision part to the near vision part via the progressive intermediate vision part. Therefore, in this arrangement (configuration), the frequencies of intermediate vision and near vision gradually increase. The lens layer A is made of an optically transparent material having a variable refractive index value. A1 corresponds to the distance vision portion of the lens, A2 corresponds to the progressive intermediate vision portion of the lens, and A3 corresponds to the near vision portion of the lens.

  The progressive intermediate vision portion A2 is located between the broken line 2a and the broken line 3a of the lens. The broken line 2a designates the lower surface of the far vision part A1 having a refractive index of N1, and the broken line 3a designates the upper surface of the near vision part A3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision portion A2 is a low refractive index value equal to the low refractive index value of the refractive index N1 of the far vision portion A1 adjacent to the progressive intermediate vision portion A2, and is close to the progressive intermediate vision portion A2. It increases to a high refractive index value equal to the high refractive index value of the refractive index N3 of the visual acuity part A3. The gradient profile has a regular and continuous rate of change. The lens layer B is made of an optically transparent material having a variable refractive index value. B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens.

  The progressive intermediate vision portion B2 is located between the broken line 2p and the broken line 3p of the lens. The broken line 2p designates the lower surface of the far vision part B1 having a refractive index of N4, and the broken line 3p designates the upper surface of the near vision part B3 having a refractive index of N6. The refractive index N5 of the progressive intermediate vision portion B2 is a high refractive index value equal to the high refractive index value of the refractive index N4 of the far vision portion B1 adjacent to the progressive intermediate vision portion B2, and is close to the progressive intermediate vision portion B2. It decreases to a low refractive index value equal to the low refractive index value of the refractive index N6 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  In FIG. 11 (a), the dashed lines 2a, 3a, 2p, 3p representing the respective refractive index gradients of the lens parts A, B cooperate and are aligned to provide a vision part of the aligned lens. Is being adjusted. This alignment means that the refractive index gradients share a common level and range. In addition, being aligned means that the surfaces defining the orientation angles of the upper surface and the lower surface of the two refractive index gradient portions generally coincide. The refractive index gradient orientation angle (OA) of the lens of this example is 8 °. It is obtained by tilting the refractive index medium in the lens body. Further, the range (width) (IE) of the progressive intermediate vision portion is 14 mm.

  The front surface 4 of the lens part A has a curvature having a radius value R1. The internal interface I has a curvature R2. The rear surface 5 of the rear lens part B has a curvature having a radius value R3. The correlation values of R1, R2, and R3 represented in the example lenses having concave, planar, and convex internal curved interfaces are related CREN values, refractive index values (N1-N6), lens thicknesses (CT, ET). ), And the optical conic constant value (CC). The three lenses of the example provide 0 degrees in the distance vision portion of the lens and 2.5 diopters addition power in the near vision portion of the lens.

  The three lenses of the examples shown below provide 0 degrees in the distance vision portion of the lens and 3.5 diopters addition power in the near vision portion of the lens.

  As shown in FIG. 11B, the front lens portion A has a minus power and the rear lens portion B has a plus power. The refractive index of the front lens part A decreases from the far vision part to the near vision part via its progressive intermediate vision part. Then, the refractive index of the rear lens part B increases from the far vision part to the near vision part via the progressive intermediate vision part. Therefore, this arrangement (configuration) represents that the power of intermediate vision and near vision gradually increases.

  The lens layer A is made of an optically transparent material having a variable refractive index value. A1 corresponds to the distance vision portion of the lens, A2 corresponds to the progressive intermediate vision portion of the lens, and A3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion A2 is located between the broken line 2a and the broken line 3a of the lens. The broken line 2a designates the lower surface of the far vision part A1 having a refractive index of N1, and the broken line 3a designates the upper surface of the near vision part A3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision portion A2 is determined from the high refractive index value equal to the high refractive index value of the refractive index N1 of the far vision portion A1 adjacent to the progressive intermediate vision portion A2, and is close to the progressive intermediate vision portion A2. It decreases to a low refractive index value equal to the low refractive index value of the refractive index N3 of the visual acuity part A3. The gradient profile has a regular and continuous rate of change.

  The lens layer B shown in FIG. 11B is made of an optically transparent material having a variable refractive index value. B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion B2 is located between the broken line 2p and the broken line 3p of the lens. The broken line 2p designates the lower surface of the far vision part B1 having a refractive index of N4, and the broken line 3p designates the upper surface of the near vision part B3 having a refractive index of N6. The refractive index N5 of the progressive intermediate vision part B2 is a low refractive index value equal to the low refractive index value of the refractive index N4 of the far vision part B1 adjacent to the progressive intermediate vision part B2, and is close to the progressive intermediate vision part B2. It increases to a high refractive index value equal to the high refractive index value of the refractive index N6 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  In FIG. 11 (b), the broken lines 2a, 3a, 2p, and 3p representing the refractive index gradient portions of the lens portions A and B are correctly positioned to provide a modified rate of lens power. Not matched. The lack of alignment of the dashed lines 2a, 3a, 2p, 3p means that the refractive index gradient does not share either a common level or a common range or any of them. Further, this incorrect alignment means that the surfaces defining the orientation angles of the upper surface and the lower surface of the two refractive index gradient portions do not coincide with each other. The two refractive index gradient portions of the adjacent lens portions are not aligned so that one refractive index gradient portion is disposed above or below the level of the other refractive index gradient portion of the adjacent lens portion. Also good.

  In FIG. 11B, the refractive index gradient portion defined by the broken lines 2p and 3p of the rear lens portion B is disposed 3 mm below the refractive index gradient portion defined by the broken lines 2a and 3a of the front lens portion A. ing. Thereby, a small refractive index change rate is provided at the boundary of the gradient ratio part, and in the extreme case, it leads to a more gradual (gradual) power change of the progressive intermediate vision part.

  The orientation angle (OA) of each refractive index gradient of the lens of this example is 8 °. It is obtained by tilting the lens forward as described above. Further, the range (width) (IE) of the progressive intermediate vision portion is 10 mm. The front surface 4 of the lens part A has a curvature having a radius value R1. The internal interface I has a curvature R2. The rear surface 5 of the rear lens part B has a curvature having a radius value R3. The correlation values of R1, R2, and R3 represented in the example lenses having concave, planar, and convex internal curved interfaces are related CREN values, refractive index values (N1-N6), lens thicknesses (CT, ET). ), And the optical conic constant value (CC). The three lenses of the example provide 0 degrees in the distance vision portion of the lens and 3.0 diopters addition power in the near vision portion of the lens.

  FIGS. 12 (a) and 12 (b) illustrate the configuration of two triplet lenses of the sixth embodiment made in accordance with this disclosure. In these embodiments, only one figure is used to describe the range of possible shapes. The lenses shown in FIGS. 12A and 12B have the same characteristics and the same refractive index portions N1, N2, N3, N4, N5 as the lens of the fifth embodiment shown in FIGS. 11A and 11B. N6. Both the front lens part A and the rear lens part B include a refractive index gradient part of the lens. In addition, the lenses in FIGS. 12 (a) and 12 (b) have a third coupled lens layer C obtained according to the patient's prescription. The rear lens portion C is made of an optically transparent material having an overall refractive index N7 that is constant.

  In FIG. 12A, the lens part C is positioned adjacent to the lens part B, and is therefore the last layer of the lens. In FIG. 12B, the lens portion C is positioned adjacent to the lens portion A, and is therefore the foremost layer of the lens. In any form, the lens part C is positioned adjacent to either the lens part A or the lens part B. In the lens blank shape, the lens of FIG. 12A has a lens portion C with a sufficient thickness processed according to the patient's prescription. The final center thickness of the lens portion C is about 0.25 mm.

  The correlation values of R1, R2, R3 and R4 of the two example lenses with various internal curved interfaces R2 are the associated CREN value, refractive index value (N1-N7), lens thickness (CT, ET), And the optical conic constant values (CC) are shown in the table below. The equation for determining the CREN number (value) is modified to include a value corresponding to the additional lens layer C. And it is represented by surface diopter as follows.

Formula 5

D1 + 2 + D2 + D3 + (D3-D4) = CREN
(However, D1, D3, and D4 are the absolute values of the surface diopters of R1, R3, and R4, respectively, and D2, which is the surface diopter power of R2, is curved with respect to the lens portion A. Is positive, and is negative when the curvature is concave with respect to the lens portion A. (D3-D4) is an unsigned value.)

  In order to provide a lens having a minimum bulk or “gross sag” and maximum CREN efficiency, both lens parts A and B share more or less equally to provide a progressive addition power of the lens. It is preferable to do. By setting the thickness of the lens portion C to a value larger than the above-described center thickness of 0.25 mm, the lens CREN value and optical performance efficiency can be slightly increased. By doing some of the slightly flattened lens curvature, the overall thickness of the lens is increased, but the properties are balanced. In order to provide improved optical properties, increase CREN efficiency, and reduce lens thickness and volume, the center thickness of lens portion C is preferably between 0.25 and 1.0 mm.

  For patient prescriptions that require a positive power in the distance vision portion of the lens, the center thickness of the lens portion C may exceed 1 mm. Conversely, for patient prescriptions that require negative power in the distance vision portion of the lens, the edge thickness of lens portion C and all lenses increases. In the following lens embodiment, a center thickness of 0.5 mm is selected for the lens part C. In addition, for convenience, to provide a patient prescription that allows the use of the thin lens portion C, the R4 value of the lens portion C equal to the R3 value of the lens portion B is When adjacent to part B, it is used in the following examples.

  Also, the R4 value of the lens unit C equal to the R1 value of the lens unit A is used in the following embodiments when the lens unit C is adjacent to the lens unit A. Lens part A and lens part B share about 50% power of the two lens parts so that both the power sign (+ or-) and the orientation of the refractive index gradient profile are opposite. By this, there is an opportunity to increase the refractive index difference or RID value of the lens up to double.

  Thereby, the percentage function between the lens parts can be shifted, and excellent optical characteristics can be maintained. However, doing so increases both the gross loss of the lens and the CREN value. The percentage shift is advantageous for either lens part A or lens part B. For example, an advantageous change in lens part A results in an increase in surface diopter power and center thickness of lens part A and a decrease in surface power and edge thickness of lens part B. The percentage change is partly or equal to 100% (when the lens part A is in full motion) and is quite steep. And the lens part B does not contribute to the addition function of a lens, but becomes a planar lens substantially. In this case, the lens is substantially the same as the lens of the first embodiment.

  There is only one lens part including the refractive index gradient part of the lens. Therefore, it is understood that the lens of the sixth embodiment has a CREN value that varies from the maximum efficiency value to the approximate maximum efficiency value of a lens having only one lens portion having a refractive index gradient. This maximum efficiency value results from the optimal sharing and combination of both lens parts A and B where the addition is occurring.

  In the following parameters of the lens 12 (a), the CREN value in parentheses represents the CREN value when the lens part A provides 100% addition power and the lens part B does not provide anything. In the following parameters of the lens 12 (b), the CREN value in parentheses represents the CREN value when the lens part B provides 100% addition power and the lens part A does not provide anything. The CREN value for each example lens is in the range between these two values. These two values are based on the percentage that each part contributes to the addition power of the lens.

  The orientation angle OA and the progressive intermediate vision part range IE are the same as those of the lenses of the examples of FIGS. 11 (a) and 11 (b). And it is not shown in the following lens parameters. These lenses provide 0 degrees in the distance vision portion of the lens and 3.5 diopters addition power in the near vision portion of the lens.

  FIGS. 13-18 illustrate additional embodiments of lenses configured in accordance with this disclosure. They have a multilayered Fresnel lens with a refractive index gradient. As described above, the surface of the Furnel lens has a large number of discontinuous coaxial (concentric) annular portions. The multiple discontinuous coaxial annulus defines a slope corresponding to a continuous lens surface shape and is collapsed to form a lower profile surface. Each adjacent optically functional annular section has a non-optically functional step (a non-optionally functional step), and each step is also annulus. It is in the form of an (annular band). These steps, along with a number of refractive surfaces, determine the overall shape and lens thickness of the lens.

  Fullelens are not typically used for ophthalmic lenses because the image quality of such lenses is generally considered poor. If the lens surface is not manufactured with very high accuracy, not only does image jump occur, but the efficiency (performance) of the lens is particularly bad because it increases the gaze angle, tilt angle or ray angle. This bad efficiency occurs when the light rays that should have entered the eye are blocked by non-optical functional steps (steps that are not optically functional). The orientation angle of the non-optical function step does not match the ray path. Light loss is most noticeable around the lens. The loss affects the vision through the upper part of the distance vision part of the lens, the side surface of the lens, and the lower part of the near vision part of the lens. In addition, there is light loss due to diffraction, scattering, and reflection from the rough surface. Of course, depending on the person, there is a concern about the decorative surface (the point of appearance) when wearing a lens such as a transparent Victrola record ("Victrola records" / registered trademark).

  In accordance with this disclosure, three steps are taken to greatly improve the performance and appearance of the fullnel lens so that the fullnel lens is used for ophthalmology. As a first step, each annulus including a non-optical functional step is a light beam that passes through a point on the lens from a plurality of points in the field corresponding to the patient's line of sight to the patient's eyes. Oriented at substantially the same angle. A problem arises regarding which point should be selected as the exit pupil. There are two main positions that can be considered.

  One is the pupil position of the eye when the patient is looking straight ahead through the center of the lens. The other is the center of rotation of the eye. It is a position that may be considered an “exit” pupil when the patient is looking through the periphery of the lens. It is true that when the patient is looking straight ahead, the objects seen in the surrounding area (the surrounding field) have good contrast and clarity. However, if the position of the pupil of the eye when the patient is looking straight ahead is used to determine the tilt of the non-optical function step, the eye passes through the left, right or lower near part of the lens. When staring at an object, the step disturbs the rays and somewhat degrades peripheral vision.

  Conversely, it is true that the objects seen in the patient's peripheral field have good contrast and clarity when staring at angles through the left, right and lower near vision parts of the lens. However, if the center of rotation of the eye is used to determine the tilt of the non-optical function step, when the eye is looking straight ahead in the center of the lens, the step disturbs the ray, thereby causing peripheral vision Some decrease.

When the patient is looking straight ahead, the pupil is located approximately 16 mm after the back surface of the spectacle lens. On the other hand, the center of rotation of the eye is located about 28.5 mm after the rear surface of the spectacle lens. Any location or some point between them is used to determine the tilt angle of the step. And excellent results are obtained. Furthermore, an improved effect is obtained by selecting a point on the back of the lens that is greater than about 15 mm as the position defining the exit pupil. A distance of 21 mm from the rear surface of the lens to the position of the exit pupil is a non-optical functional step of about 8 ° with respect to the two extreme eye orientations described in relation to the peripheral rays directed at that position. Results in approximately equal angular errors.

  The slope of each step is equal to the angle of the refracted ray that passes through the lens at that step location and travels from the lens to the exit pupil. Each step is visualized as one of a series of annular right circular concentric conical sections (a concentric ring at the bottom of the right cone) Has been. Each of these annular and straight concentric conical portions is formed by a common portion (conical surface) of the conical surface and the lens body. This is because these conical surfaces follow the path of refracted rays traveling through the lens to some extent and form their vertices at the 21 mm distance mentioned above or at other distances on the rear surface of the lens.

  A second step that can be taken to improve the performance of the inventive fullnel lens is to bond the lens layer adjacent to the fullnel surface as a cast layer. It totally eliminates or limits the reflection and Frunnel diffraction of one part (either the upper part of the far vision part or the lower part of the near vision part), while protecting the fragile fullernel shape, and other others Reflection and diffraction are substantially reduced in the part. When the refractive index of the bonded part is equal to the refractive index of the fullnel preform, not only the function of the fullnel but also its visibility and visual degradation are completely eliminated. Such a region of the doublet Flannel lens functions as a single index optical window of refractive index. It is the ideal (typical) of the distance vision part of the lens.

  As a third step, refraction of the combined part (combined addition part) providing a progressive addition power, for example by using a high power fullnel preform of either 20 diopters plus or minus power. The rate can be somewhat close to the refractive index of the preform. The higher the power, the smaller the required refractive index difference. The refractive index of the combined add power portion is greater or less than the refractive index of the preform. Then, the refractive index of the combined addition portion becomes plus or minus depending on whether or not the fullnel preform is plus or minus. The use of a high number of fullnel preforms with combined additivity portions offers the advantage that diffraction, light scattering, reflection, surface shape, and surface errors or surface damage (damage) are visibly reduced. . The combined add power portion has a refractive index somewhat close to that of the full-nel preform.

  FIG. 13 shows the configuration of a doublet Fnelnel lens that defines the lens of the seventh embodiment configured according to this disclosure. In the lens of FIG. 13, the non-optical function step (surface forming the stepped portion) is normal to the lens shape. And that step does not match the described exit pupil. In FIG. 13, the lens portion A constitutes an overall constant refractive index portion of the lens, and the lens portion B constitutes a refractive index gradient portion of the lens. The front lens part A has a negative power and the rear lens part B has a positive power. In this typical lens, the refractive index increases from the far vision portion to the near vision portion via the progressive intermediate vision portion of the gradient lens portion B. Therefore, the frequencies of intermediate vision and near vision are gradually increasing.

  The thickness of the lens part B is the minimum, and therefore the refractive index gradient part located between the broken line 2 and the broken line 3 is also the smallest (about 0.4 mm), so there is no refractive index orientation angle. . In addition, the curvature (or more appropriately, the “shape” of the Furnell surface) is independent of the power of the Furnell lens, so the boundary surface with the air deviates significantly from the Furnnel diopter curvature form or shape Unless otherwise, the CREN value is 0 or a small value. In addition, if one of the Furnell surface regions is not canceled by adjacent layer portions having the same refractive index, the CREN value is 0 or a small value in this case as well. In these cases, the plus or minus power provided by one or both of the air and boundary surfaces is required to correct the lens to the distance standard "0" power. The CREN equation of the full-nel lens of this embodiment is modified as follows.

Equation 6

1000 / R1-2 ・ 1000 / R2 + 1000 / R3 = CREN
(However, R1, R2, and R3 indicate the absolute values of the surface radii, and R2 is a Furnel's diopter curved shape (R2f), which is independent of its actual surface power.) Curvature correction is not required for R1 and R3 for lenses where the refractive index of the layer portion with the gradient index (eg, distance vision portion) is the same as the refractive power of the full-nell preform to which it is joined, and so on In this case, R1 and R3 (whether R2 is flat or curved) may be “parallel” to the shape or outer shape (curved surface) of R2. In this case, as shown in the following substituted equation, when R1, R2, and R3 are 250 mm, the CREN value ends with “0”.

Equation 7

              4-8 + 4 = 0

  When R1 and R3 are not parallel to R2, for example, R2 is flat, R1 is 333 mm, and R3 is 333 mm, the CREN value is 6. This indicates some volume or gross settlement for the lens. CREN values for the full-lens lenses of this example range from 0 to 20, and are shown with the relevant lens parameters for the full-lens lenses of each example.

  In FIG. 13, the rear lens part B is made of an optically transparent material having a variable refractive index value. B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion B2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part B1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part B3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision part B2 is a low refractive index value equal to the low refractive index value of the refractive index N1 of the far vision part B1 adjacent to the progressive intermediate vision part B2, and is close to the progressive intermediate vision part B2. It increases to a high refractive index value equal to the high refractive index value of the refractive index N3 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  The front lens portion A is a fullnel preform lens made of an optically transparent material. The refractive index N4 of the optically transparent material is generally constant and does not change. The front surface 4 of the lens portion A has a curvature R1 that is a plane. The internal Furnell interface I has a shape R2f that is generally a plane, an equivalent Furnell radius R2r with respect to the lens part A, and a conic constant value CC. The rear surface 5 of the rear lens portion B has a curvature R3 that is a plane.

  This lens provides 0 power in the distance vision portion of the lens and high diopter addition power in the near vision portion of the lens, as shown below. The front surface 4 may be processed according to the patient's prescription. Both the front surface 4 and the back surface 5 may be machined to provide a meniscus curved shape. The values of the lenses of the four examples are shown below.

  In the full-lens lens of the above example, a point E located approximately 21 mm behind the lens rear surface 5 was selected as the exit pupil. The fullel shape is not corrected by the angle corresponding to the fullnel step, but this point E is an effective reference for determining the efficiency of the uncorrected fullel shape.

  FIG. 14 is an enlarged view of two optical functional gradients (inclined surfaces) 6 and 7 together with non-optical functional steps (steps) 8, 9, 10, and 11 of the shape R2r of the internal Furnell interface I in FIG. 13. is there. This is indicated by the arrows in FIG. The beam bundles 12 and 13 are shown as having predetermined diameters 14 and 15, respectively. Both beam bundles 12 and 13 are refracted through the lens at two slightly different angles and travel towards the exit pupil E. As can be seen from FIG. 14, a considerable amount of light bundles 12, 13 are obstructed or cut (cut) by steps 8, 9, 10, 11. And as a result, the lens is quite inefficient at its periphery.

  The lens example # 1 in FIG. 14 constitutes a fullnel preform (lens layer) A. The fullnel preform A has a negative focal length of 50 mm, a refractive index N4 of 1.491, a fullnel radius R2r of −24.68 mm, and a conic constant of −0.631. This preform A is combined with a cast fullnel layer B having a thickness of 0.4 mm. The molded Furnell layer B includes a refractive index N1 of 1.491, a gradient refractive index N2 that increases from 1.491 to 1.58, and a refractive index N3 of 1.58. The lens provides a progressive addition of 3.5 diopters. The two rays are selected at the peripheral angles of 35 ° and 45 ° towards the exit pupil described above. At that position, the light beam refracted at 45 ° passes through one annular portion of the inner Furnell interface. The surface slope is 44.67 ° and has a calculated step depth of 0.25095 mm over a selected groove width of 0.254 mm.

  On the other hand, at a position refracted at 35 °, the light flux passes through one annular portion of the internal Furnell interface. The surface slope is 32.51 ° and has a calculated step depth (step) of 0.16210 mm over a groove width of 0.254 mm. A 45 ° ray is refracted from an internal ray angle of 26.59 °, and a 35 ° ray is refracted from an internal ray angle of 21.29 °. The 26.59 ° ray shows a loss from the interface of the 0.25095 mm high (outer) step annulus resulting in a 49.5% reduction in light. And the 35 ° light beam shows a loss from the interface of the 0.16210 mm high (outer) step annulus resulting in a 25% light reduction.

  There is negligible light loss through the part where the refractive index of the lens part A and the lens part B is the same. That is, in this example, the refractive index of the lens part A and the lens part B is 1.491. In this case, the surface shape of the Furnell interface is not visible and becomes inefficient. The step angle of the near vision part with a refractive index difference of 0.089 should be corrected. In addition, optical materials with similar Abbe values should be selected to avoid or minimize chromatic aberration. Alternatively, a substance that compensates (cancels) Abbe characteristics may be selected to correct chromatic aberration.

  FIG. 15 shows the configuration of a doublet Flannel lens of the lens of the eighth embodiment configured according to this disclosure. The doublet lens is the same as that shown in FIG. 13 except that the inclination of the annular step is corrected as described above in order to minimize the disturbance of the light beam around the lens. Is the same. The surface radius, refractive index, lens part power, thickness and add power of the lens are the same as those shown for the lens of Example # 1 with respect to FIG.

  FIG. 16 is an enlarged view of two optical functional slopes (inclined surfaces) 6 and 7 together with non-optical functional steps (steps) 8, 9, 10, and 11 of the shape R2r of the internal Furnell interface I in FIG. 15. is there. This is indicated by the arrows in FIG. The beam bundles 12 and 13 are shown as having the same diameters 14 and 15 as shown in FIG. Both the light bundles 12 and 13 are refracted through the lens and travel toward the exit pupil E. As can be seen from the figure, there is no obstruction or cut of the beam bundle due to steps 8, 9, 10 and 11 at the Fullel interface.

  As a result, light loss is minimal and the lens is very efficient at its periphery. Provides high contrast, high brightness and high clarity visualization of objects in the peripheral side field of the lens and through the near vision part of the lens. As described above, the annular fullnel step is optimized for the exit pupil at a position 21 mm after the rear surface of the spectacle lens. Thereby, only a slight disturbance of both the straight forward gaze and peripheral gaze rays by the patient is brought about.

  In the Frunnel lens of the above example, the inner Fnelnel interface I is generally planar so that it is the most commercially available Frunnel lens. However, the shape of the lens may be other than a plane. For example, the surfaces R1 and R3 may be curved in a meniscus shape that resembles a standard ophthalmic lens. In this case, the thickness of the lens increases as a result of an increase in the center thickness of the lens part A and an increase in the edge thickness of the lens part B. By using a low diopter curvature, the increase in thickness is within reasonable limits.

  FIG. 17 illustrates a lens of a ninth embodiment configured according to this disclosure. The lens of FIG. 17 is a triplet fullnel lens that includes a third lens layer C coupled thereto. In FIG. 17, the internal Furnell interface I is generally a plane. The shape of the lens as described above is a meniscus, which is similar to a standard ophthalmic lens. The lens has non-optical function steps (steps). The non-optical functional steps are normal (orthogonal) to the lens surface, or are angled and corrected as described above in connection with FIGS. .

  In FIG. 17, the lens part A includes a (first) full-nel preform having a constant refractive index as a whole. The lens part B includes a refractive index gradient part of the lens. The lens unit C includes a second preform. The front lens part A has a negative power, the rear lens part B has a positive power, and the lens part C has a negative power. In this embodiment, the refractive index increases from the far vision portion to the near vision portion via the progressive intermediate vision portion of the gradient lens portion B. For this reason, the frequencies of intermediate visual acuity and near visual acuity gradually increase.

  As with the full-lens lens of the above-described embodiment, since the thickness of the lens portion B is minimum, there is no refractive index orientation angle. Therefore, the thickness of the refractive index gradient portion located between the broken line 2 and the broken line 3 of the lens is also minimum (about 0.35 mm). The refractive index gradient lens layer B functions as an optical bonding agent between the lens layer A and the lens layer C. B1 corresponds to the distance vision portion of the lens, B2 corresponds to the progressive intermediate vision portion of the lens, and B3 corresponds to the near vision portion of the lens.

  The progressive intermediate vision portion B2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part B1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part B3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision part B2 is a low refractive index value equal to the low refractive index value of the refractive index N1 of the far vision part B1 adjacent to the progressive intermediate vision part B2, and is close to the progressive intermediate vision part B2. It increases to a high refractive index value equal to the high refractive index value of the refractive index N3 of the visual acuity part B3. The gradient profile has a regular and continuous rate of change.

  The front lens portion A is a fullnel preform lens made of an optically transparent material. The refractive index N4 of the optically transparent material is generally constant. The rear lens layer C is a preform lens having a refractive index N5. The inner surface 5 of the lens part C may be planar or slightly convex with respect to the lens part C in order to promote the bubble-free joining to the refractive index gradient optical cement constituting the lens part B. It has a good curvature R3. The front surface 4 and the back surface 6 may be machined according to the patient's prescription. The curved convex surface of the front surface 4 of 3 diopters and the curved concave surface of the rear surface 6 provide a typical meniscus lens shape for an ophthalmic lens.

  The center thickness and edge thickness in a 50 mm diameter lens with the following parameters are within the reasonable range of ophthalmic lenses. They are shown in the table below. The lens provides a '0' power in the distance vision portion of the lens and a 3.265 diopter addition power in the near vision portion of the lens. A high refractive index preform results in a sufficiently thin lens. Thereby, the front surface 4 and the rear surface 6 are greatly curved.

  The fullnel of the above example may be manufactured so that the refractive index gradient portion of the lens is provided in one or both lens portions as in the above-described embodiment of the present specification. However, in the Fullel lens type, it is preferable that only one refractive index gradient portion includes the refractive gradient ratio. In addition, a lens similar to the lens of the fifth embodiment may provide a modified rate of change of the desired frequency. In the lens, both refractive index gradients include refractive index gradients, and the progressive intermediate is not aligned. The fullnel preform may have either a positive power or a negative power. It is positioned as either the front lens layer or the rear lens layer. The refractive index of a portion of the gradient index layer may be the same as or different from the refractive index of the corresponding portion of the adjacent combined layer. Also, the internal Frunnel surface may be typically flat with the overall shape of the lens being either flat or curved.

  FIG. 18 (a) shows a doublet Furnell lens configuration of the lens of the tenth embodiment configured in accordance with this disclosure. The lens of FIG. 18 (a) also has a curved inner fullnel surface R2, as well as curved surfaces R1 and R3. In the tenth embodiment, the full-lens shape includes the deformed shape of the non-optical function step (step portion) as described above, in addition to the curved inner full-nel surface R2. Due to its curved surface R2, the meniscus shape is used without an increased CREN value and added thickness of the lens. In other words, the curvature of the inner Furnell surface R2 may approximate the curvature of the surface R1 or R3.

  The internal Furnell surface R2 associated with the surface R1 and the surface R3 is such that the path of the rays in the lens body is approximately orthogonal to the Furnell shape, so that the non-optical functional steps are also orthogonal to the Furnell shape. A larger curved lens may be provided. This occurs when the radius of the rear surface 5 is approximately equal to the distance to the exit pupil. This translates into a curvature of 47.6 diopters, which is an excessively steep ophthalmic lens, wherever it is viewed. Accordingly, the curvature R2 is preferably reduced to a typical value (for example, 200 mm (5 diopter curve)) of the basic curve (curve) of a standard ophthalmic lens, and the step angle is preferably corrected accordingly. In this embodiment, the exit pupil E is located 28.5 mm after the rear surface of the spectacle lens.

  The lens portion A in FIG. 18A includes a refractive index gradient portion of the lens, and the lens portion B includes a generally constant refractive index portion of the lens. The front lens part A has a negative power and the rear lens part B has a positive power. In this embodiment, the refractive index decreases from the far vision portion to the near vision portion via the progressive intermediate vision portion of the gradient lens portion A. Therefore, the frequencies of intermediate vision and near vision gradually increase.

  The lens layer A is made of an optically transparent material having a variable refractive index value. A1 corresponds to the distance vision portion of the lens, A2 corresponds to the progressive intermediate vision portion of the lens, and A3 corresponds to the near vision portion of the lens. The progressive intermediate vision portion A2 is located between the broken line 2 and the broken line 3 of the lens. The broken line 2 designates the lower surface of the far vision part A1 having a refractive index of N1, and the broken line 3 designates the upper surface of the near vision part A3 having a refractive index of N3. The refractive index N2 of the progressive intermediate vision portion A2 is determined from the high refractive index value equal to the high refractive index value of the refractive index N1 of the far vision portion A1 adjacent to the progressive intermediate vision portion A2, and is close to the progressive intermediate vision portion A2. It decreases to a low refractive index value equal to the low refractive index value of the refractive index N3 of the vision portion A3. The gradient profile has a regular and continuous rate of change.

  The rear lens part B is a fullnel preform lens made of an optically transparent material. The refractive index N4 of the optically transparent material is generally constant. The front surface 4 of the lens layer A has a curved convex surface R1. The internal Furnell interface I is concave with respect to the lens part A, has the same Furnell radius R2r, and has a shape R2f having a conic constant value CC. The rear surface 5 of the rear lens portion B has a curved concave surface R3. The range of the progressive intermediate portion IE is 16 mm.

  This lens provides a “0” power in the distance vision portion of the lens and a 2.278 diopter addition power in the near vision portion of the lens. The rear surface 5 may be processed according to the patient's prescription. The values of the lenses of the examples are shown below.

  The refractive index gradient portion of the planar shape Furnell lens of FIGS. 13, 15, and 17 may be manufactured using a spraying method as described above. In that method, two spray guns are used. The spray guns move together along a straight or arcuate path. In such a state, the two spray guns are capable of depositing a lens having a width of 4 to 20 mm or exceeding the range of the lens (a deposit such as a stack of resin sprayed from the two guns or a common one). One of the refractive index resins is sprayed onto the surface of the Furnell preform so as to obtain a deposit.

  A thin separating vertical wall is placed on the sprayed resin deposit between the two spray guns. The separating vertical wall is linearly arranged in the direction of movement of the spray gun. The separation vertical wall is divided into a far vision portion and a near vision portion, and blocks unnecessary spray from each gun from being accumulated in those adjacent portions. The extent of the overlap region or blend region may be increased or decreased. The range is also easily controlled first by adjusting the gun spray direction and spray pattern and secondly by adjusting the height of the separation wall.

  The spraying process is performed while the spray gun continues to move back and forth in a straight or arcuate manner, ensuring the amount and uniform distribution of the resinous material deposited across the surface of the Furnell lens. The spraying process further ensures that the two resins are thoroughly mixed in the blended region, such as by sprayed deposit movement. The deposit movement is caused by the effects of both spray gun resin mist and air pressure. The spray device described in connection with FIG. 21 is used to perform the spray method described above.

  FIG. 19 shows two sprayed deposition areas. These regions include overlapping regions or common regions with gradient rate mixing. In this case, the deposits of both spray patterns are circular. However, they may have different shapes, such as an ellipse. Circular deposit A and circular deposit B share a common area A + B. The amount of change in each resin contributes to the composition (configuration) over the range of the common region represented by line AB. Due to the variable chord length CL (parallel to LP) of each circular deposit (resin mixture) in A + B, as well as the linear or arcuate movement and path of the gun in the LP direction, the refractive index of the composition is , Shows a smooth and continuous regular rate of change in a direction orthogonal to LP. It closely follows the position of π / 2 to 3π / 2 in a sinusoidal shape.

  Once the depth of the sprayed deposit is somewhat above the level of the filled voids (steps) on the Furnell surface, the lens is fully cured or polymerized. The lens is then machined and processed as described above. Alternatively, a protective layer or an additional portion such as the lens portion C in FIG. 17 or FIG. 18B may be supplied to the surface of the liquid resin and polymerized. This forms a permanently bonded layer. Alternatively (alternatively), a removable casting member may be provided on the top surface of the resin surface. The top surface is then subjected to polymerization and subsequent removal to produce an optical quality surface such as the back surface 5 shown in FIG.

  The refractive index gradient portion of the curved-shaped fullel lens of FIG. 18 (a) is manufactured in a similar manner using two gun spray systems that manufacture the refractive index gradient region composition. In this case, the resin has a desired thickness (for example, a thickness of 0.35 mm), is flexible, and is deposited on a flat surface. Once deposited, the resin may be partially polymerized into a gel. Following this stage, the flexible surface may be deformed or expanded (relaxed) to correspond to a full-nell preform.

  The surface is then pressed against the preform and polymerized to permanently bond the gelled layer to the Furnell surface. The lens layer C including the flexible surface may remain as a part of the lens as shown in FIG. 18B, or may be removed and reused or disposed of. A flexible surface as described above may be expanded to the desired curvature or may be expanded by mechanical or other means (eg, a vacuum forming process). This causes deformation to a desired curve.

  FIG. 20 shows an eleventh embodiment lens constructed in accordance with this disclosure. The lens in FIG. 20 is a refractive index gradient type progressive lens. The lens has multiple layers with a plurality of refractive index gradients and a power sign ("-"). Each frequency code is opposite to the frequency code of the adjacent layer. As already explained, a set of refractive index gradient profiles is effectively used in adjacent plus and minus power layers to increase or double the refractive index difference. Thereby providing a means to obtain a high progressive addition with a low or plane curvature and a reduced lens thickness. This embodiment operates on the same principle.

  However, in order to obtain similar results, a large number of thin, low-curvature pairs are utilized. Film layers with a thickness of 0.3 mm or less are combined in various numbers to create a corresponding progressive addition. For example, if at opposite powers, a pair of layers with opposite slope rate profiles provide 0.417 diopters, six identical pairs of layers provide 2.5 diopters.

  In FIG. 20, the front lens portion A is entirely composed of a constant refractive index layer, and the lens portion B, the lens portion C, the lens portion D, and the lens portion E constitute a refractive index gradient layer of the lens. There are six lens parts C and five lens parts D. The lens part B and the lens part E have the same power and are added together with the configuration of the additional lens part D. The power of the pair of lens part C and lens part D is opposite to each other and equal.

  The lens part A has a positive power and cancels the negative “additional power” number above the far vision part of the lens. Lens part B has a positive power, lens part C has a negative power, lens part D has a positive power, and lens part E has a positive power. In the lens of this embodiment, the refractive index decreases from the far vision portion to the near vision portion via the progressive intermediate vision portion of the gradient index lens portion C. Further, the distance increases from the far vision portion to the near vision portion through the progressive intermediate vision portion of the refractive index gradient lens portion D. Thus, the intermediate and near vision powers are complex and gradually increasing.

  The lens layer A is made of an optically transparent material having an overall refractive index N1 that is constant. The lens layer B is made of an optically transparent material having a variable refractive index value. B1 corresponds to the distance vision portion of the lens and has a refractive index value N2. B2 corresponds to the progressive intermediate vision portion of the lens, and has a gradient refractive index value N3. B3 corresponds to the near vision portion of the lens and has a refractive index value N4. The lens layer C is made of an optically transparent material having a variable refractive index value. C1 corresponds to the distance vision portion of the lens and has a refractive index value N5. C2 corresponds to the progressive intermediate vision portion of the lens and has a gradient refractive index value N6. C3 corresponds to the near vision portion of the lens and has a refractive index value N7.

  The lens layer D is made of an optically transparent material having a variable refractive index value. D1 corresponds to the distance vision portion of the lens and has a refractive index value N8. D2 corresponds to the progressive intermediate vision portion of the lens and has a gradient refractive index value N9. D3 corresponds to the near vision portion of the lens and has a refractive index value N10. The lens layer E is made of an optically transparent material having a variable refractive index value. E1 corresponds to the far vision portion of the lens and has a refractive index value N11. E2 corresponds to the progressive intermediate vision portion of the lens, and has a gradient refractive index value N12. E3 corresponds to the near vision portion of the lens and has a refractive index value N13. The refractive index gradient portions N3, N6, N9, and N12 are located between the broken line 2 and the broken line 3 that define the progressive intermediate vision portion of the lens.

  The front surface 4 of the lens layer A has a convex curvature having a radius value R1. The inner interface 5 has a radius R2, each inner interface 6 has a radius R3, each inner interface 7 has a radius R4, and the rear surface 8 has a radius R5. The lens part C and the lens part D share the curved interface 6 / R3 and the curved interface 7 / R4. With respect to the lens part A, R3 is a concave surface and R4 is a convex surface. Since the curvatures of adjacent internal interfaces are opposite, the CREN value of the lens according to this example is simply calculated by adding the full surface power of all surfaces. As shown in FIG. 20, a refractive index orientation angle of 8 ° is obtained by not registering increasing amounts of successive refractive index gradients. As with the previous embodiment, all radius values are based on a lens that provides 0 degrees in the distance vision portion of the lens and 2.5 diopters in the near vision portion of the lens.

  Examples of parameter values of the gradient index progressive lens according to this embodiment are shown below.

  The above-described lens is the same as the lens described in FIGS. 13, 15, 17, and 18, with a deformable substrate having a desired bending characteristic, and a procedure using the above-described spraying method with other layers. It is manufactured by processing each lens layer independently.

  FIG. 21 shows a spraying device including two spray guns S1, S2. The device is used to process (process) the lens layer. The spray gun S1 supplies a material having a refractive index of 1.74, and the spray gun S2 supplies a material having a refractive index of 1.41. Both guns move along the path LP in a linear motion. The spray guns S1 and S2 spray the substance (resin) of S1.74 and the substance (resin) of S1.41 on the substrate surface B, respectively, and are combined overlapping deposits of 14 mm wide or bonded. Produce common deposits. A thin vertical separation wall W is disposed on the resin deposit between the spray gun S1 and the spray gun S2. It is arranged linearly in the direction of movement of the spray guns S1, S2. The vertical separation wall W separates the distance portion D and the near portion N.

  Further, the vertical separation wall W prevents unwanted spray US from each spray gun from being placed in an adjacent part while controlling the amount of each sprayed resin mixed therethrough. The range of the common deposit region or common blend region may be reduced or increased. The range is first easily controlled by adjusting the spray direction and pattern of the gun, and secondly by adjusting the height of the separation wall W. Guaranteeing 30 ° cone angle from each spray gun, 15 ° converging slope of each gun, 63mm spray distance from gun tip to deposit surface, 56mm gun tip to tip distance, separation 12mm above deposit surface A slope ratio portion with a wall height of 14 mm is obtained.

  The separation wall W is also used to avoid unnecessary spraying US. However, it may be adjusted to control the width of the gradient factor within the limits. The separation wall W includes an opening connected to a vacuum source along its lowermost portion. The vacuum source draws the deposited resin. And in order to avoid that the droplet of a substance falls from the wall to the deposit, it is assembled apart from the sprayed area and the separation wall W.

  The flexible and deformable substrate B has a surface on which the first resin layer is sprayed and the vertical separation wall W is disposed. The deformable substrate B is placed on the substrate support cylinder BS. The substrate support cylinder BS acts as a container for the sprayed resin and has an upper wall portion R extending above the substrate B. The deformable substrate B is made of a thin plastic, glass or stainless steel member. These members change their curvature by mechanical means or other means. During each spray, a change in curvature occurs in the substrate B. The substrate B in turn creates a curvature for each internal interface as new layers are applied.

  In FIG. 21, the vacuum line VL provides a partial and controllable vacuum from the vacuum source to the vacuum chamber VC. The vacuum line VL provides a suction means for pulling the deformable substrate B downward to create a curved convex surface. The following cycle line VL is pressurized to create an atmospheric pressure environment in the chamber VC. The cycle line VL provides a compression means for pushing the deformable substrate B upward to form a curved convex surface. Since R3 and R4 have a sagittal depth of 0.0974 mm or more and 50 mm, only a small amount of surface change is required to take the radius of curvature required for the substrate B. The variable thickness of the substrate B is used to ensure that when the substrate is deformed, a continuous, useful optically curved surface (eg, a curved spherical surface) is obtained.

  The first composite (synthetic) layer B1 is first created when the substrate B is maintained in a planar state. During the course of the spraying process, the sprayed resin accumulates and a layer is formed, and the substrate surface B is gradually steered into a concave shape for its final curvature. Then, as shown in FIG. 21, when the spray layer thickness is obtained, the change in curvature proceeds in response to the formation of the applied resin layer. Once the final curvature is reached and the resin layer thickness is obtained, the separation wall W may be removed. At this point, the liquid surface of the sprayed resin layer settles. After reaching a uniform level, the sprayed resin layer is photopolymerized into a gel-like body. Alternatively, a planar or slightly convex molding surface may be applied to the unpolymerized resin layer to accurately control the surface profile (curve).

  The convex molding surface is used to avoid air bubbles when applied to the air-exposed surface of the sprayed resin composition. This resin layer may then be polymerized in a gel form. Thereafter, the upper molding surface is removed. The top surface of the gel-cured deposit becomes the substrate B1 on which the second sprayed layer is applied. Therefore, fine adjustment to obtain the required curvature is made on the substrate B1 in order to obtain a flat surface B1 for applying the second layer. A second sprayed resin layer is then applied to the flat surface. However, at this time, the spray gun or lens is rotated 180 ° to obtain the opposite index profile orientation (direction).

  During the course of the second layer spraying step, the substrate surface B is gradually reduced to a concave steep slope. Then, when the spray layer thickness is obtained, the substrate surface B is gradually made a convex surface having a final steep slope. Thus, again, the change in curvature proceeds in response to the formation of the applied resin layer, and a new curved interface radius is created with a change corresponding to the curvature of the substrate B. Once the final curvature is reached and the resin layer thickness is obtained, the top surface of the sprayed liquid resin is terminated as described above. The spray gun or lens is rotated 180 ° repeatedly to obtain the opposite index profile orientation (direction) of each additional layer. Each additional layer has alternating positive or negative frequencies. Each rotation may include a gradual correction value to obtain the refractive index orientation angle indicated by dashed line 2 and dashed line 3.

  After each resin layer is spray deposited, once the lens is fully polymerized prior to gel polymerization, the curvature produced in the previous layer requires a radius of curvature. The curvature radius alternates between the R3 curvature and the R4 curvature. This requires the fine tuning that occurs due to the increase in lens thickness and the compensatory curvature that occurs at the gel polymerization stage so that the layer formation process continues. Final polymerization from gel to solid begins at the top surface of the flat surface and the substrate surface. The final lens layer A is manufactured as a preform and bonded to the composite multilayer lens. Or it is molded onto the surface B or E and polymerized.

  As an alternative to the diffusion process described above with respect to the lenses of the first to sixth embodiments, the spray technique described above may be used. Since the thickness of the refractive index gradient portion or refractive index gradient portions of these lenses is larger than the thickness of the lens of the eleventh embodiment (about 1 mm or more), the sprayed deposit having a larger thickness is used. Is needed. If a single spray with a large thickness is applied, the heavier material will settle under the lighter material by gravity if the density of the two sprayed refractive index materials is substantially different. To avoid this problem, regular gel polymerization or partial curing of the applied thin layer is initiated.

  For example, a 0.25 mm thick applied layer is sequentially gel polymerized until a final layer thickness is obtained. In this case, an additional spray coating with the same refractive index profile orientation is applied later, so that the upper molding surface does not need to be applied with a subsequent spray deposit in order to be a perfectly flat surface. These lenses with larger thickness and steep curvature utilize a deformable substrate to facilitate the spray manufacturing process and to provide the required radius. As described above, the removable molding surface is applied to the top surface obtained by final polymerization followed by removal. Alternatively, the molding surface may constitute a separately added permanently bonded lens portion that functions as a protective layer.

Claims (25)

A gradient index lens formed of at least two layers,
One of the two layers has a positive power and the other has a negative power;
One of the two layers is a first layer, a first portion having a first refractive index, a second portion having a second refractive index, the first portion, and the Having three parts with a third part between the second part and
The third portion has a refractive index gradient and extends in a direction transverse to the meridian of the refractive index gradient type lens;
The refractive index gradient type lens, wherein the refractive index gradient is configured to continuously change between the first refractive index and the second refractive index.   The refractive index gradient type lens according to claim 1, wherein the refractive index change rate of the refractive index gradient follows a sine wave progression from a maximum value to a minimum value.   The refractive index gradient lens according to claim 2, wherein the at least two layers include a continuous front curved surface and a rear curved surface. The gradient index lens is a progressive ophthalmic lens for use with a patient,
Said first portion corresponds to a first zone of vision of the patient;
Said second portion corresponds to a second zone of vision of the patient;
The refractive index gradient lens according to claim 1, wherein the third portion corresponds to an intermediate and progressive zone of a patient's vision. The first zone is a distance vision zone having a power for distance vision;
The second zone is a near vision zone having a power for near vision;
The refraction according to claim 4, wherein the third zone is an intermediate vision zone having a continuously varying power in a range between the power for the distance vision and the power for the near vision. Rate gradient lens.   5. The gradient index lens of claim 4, wherein the other of the two layers is a second layer and is combined with the first layer to be shaped to provide a vision correction prescription. The layer having the plus power includes the first layer having the three portions,
The layer having the minus power includes the second layer, and the second layer includes a vision correction prescription layer,
The refractive index gradient lens according to claim 6, wherein the visual correction prescription layer has a constant refractive index as a whole. The layer having the minus power includes the first layer having the three parts,
The layer having the positive power includes the second layer, the second layer having a vision correction prescription layer;
The refractive index gradient lens according to claim 6, wherein the visual correction prescription layer has a constant refractive index as a whole. The other of the two layers is a second layer, a first portion having a first refractive index, a second portion having a second refractive index, the first portion, and the Having three parts with a third part between the second part and
The third portion has a refractive index gradient, and extends in a transverse direction with respect to the meridian of the refractive index gradient type lens;
The refractive index gradient continuously varies between the first refractive index and the second refractive index;
The first layer and the second layer are:
a) At least a portion of the three portions of the first layer having a low refractive index and at least a portion of the three portions of the second layer having a high refractive index along the patient's line of sight Aligned, and
b) At least a portion of the three portions of the first layer having a high refractive index and at least a portion of the three portions of the second layer having a low refractive index, along the line of sight of the patient Are aligned,
The refractive index gradient type lenses according to claim 4, which are arranged in a positional relationship selected from the group consisting of: The gradient index lens further includes a third layer,
10. The gradient index lens of claim 9, wherein the third layer is a combination of the first layer and the second layer and is shaped to provide a vision correction prescription layer.   The refractive index gradient lens according to claim 10, wherein the visual correction prescription layer has a constant refractive index as a whole. The first layer has an anterior surface and a posterior surface that generally traverse the patient's line of sight via the gradient index lens;
The refractive index gradient has a range between the front surface and the rear surface;
5. A surface having a substantially constant refractive index is defined through the range, and at least a portion of the surface is generally aligned with the line of sight of the patient through the gradient index lens. Refractive index gradient lens described in 1.   The refractive index gradient lens according to claim 12, wherein the line of sight of the patient through the refractive index gradient lens follows a downward gaze.   14. The gradient index lens of claim 13, wherein the downward stare is at an angle of about 8 [deg.] With respect to a straight forward stare. Each of the at least two layers has an anterior surface and a posterior surface generally traversing the patient's line of sight via the gradient index lens;
The refractive index gradient has a range between the front surface and the rear surface;
10. A surface having a substantially constant refractive index is defined through the range, and at least a portion of the surface is generally aligned with the line of sight of the patient through the gradient index lens. Refractive index gradient lens described in 1.   The refractive index gradient lens according to claim 15, wherein the line of sight of the patient follows the downward gaze through the refractive index gradient lens.   The gradient index lens of claim 16, wherein the downward gaze is at an angle of about 8 ° with respect to a straight forward gaze. The two layers are composed of a Furnell lens and have an interface between the two layers,
The refractive index gradient lens according to claim 1, wherein the interface between the two layers is formed of a Furnell surface. The gradient index lens is a progressive ophthalmic lens for use with a patient,
The first portion corresponds to a first zone of vision of the patient;
The second portion corresponds to a second zone of vision of the patient;
19. The gradient index lens according to claim 18, wherein the third portion corresponds to an intermediate and progressive zone of the patient's vision.   The refractive index gradient lens according to claim 19, wherein the other of the two layers is a second layer having a surface processed according to a vision correction prescription.   The other of the two layers is a second layer having a substantially constant refractive index, and the substantially constant refractive index is a portion of the three portions of the first layer. The refractive index gradient lens according to claim 19, wherein the refractive index gradient lens is substantially the same as the refractive index of the lens. The Furnell surface has a plurality of non-optical functional steps, at least some of which are conical steps, the conical steps having a conical apex, and the gradient index lens is a rear surface. Have
The apex of the cone defining the conical step is located behind the rear surface of the lens;
20. The gradient index lens of claim 19, thereby providing increased light transmission from a peripheral region point to the patient's eye through the gradient index lens.   23. A gradient index lens according to claim 22, wherein the apex of the cone defining the cone step is located 16-28.5 mm after the rear surface of the gradient index lens. The gradient index lens further includes a layer,
20. The gradient index lens of claim 19, wherein the layer includes a continuous front curved surface and a rear curved surface.   The refractive index gradient lens according to claim 19, wherein the shape of the Furnell interface has a radius of curvature ranging from infinity to 21 mm.

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