JP2010507833A - Multilayer multifocal lens with blended refractive index - Google Patents

Abstract

The present invention relates to a multifocal spectacle lens. The multifocal spectacle lens includes bifocal and trifocal lenses that provide improved superficial appearance, optical properties, and a wide field of view. This multifocal spectacle lens includes a plurality of lens portions that are laminated in the axial direction with a continuous curvature (curvature) and coupled together. At least one of the multifocal spectacle lens portions has a refractive index change having a refractive index blend region extending transversely to the meridian of the lens. The blend solves the visualization of adjacent joint regions of generally constant refractive index, abrupt magnification (magnification) shifts of split multifocal lenses, and typical image jumps. A region of generally constant refractive index provides the refractive power of the individual vision portion of the lens. The other layers of the lens contain a constant or similar refractive index change.
[Selection] Figure 1

Description

  This application claims the benefit of US provisional application serial number 60 / 854,467, filed October 24, 2006.

  The present invention relates to a multifocal spectacle lens. The multifocal spectacle lens includes bifocal and trifocal lenses with improved superficial appearance, optical performance, and wide field of view. The multifocal 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 changing refractive index that provides a refractive index blend area that is transverse to the meridian of the lens. ing. The blend consists of a field of view (visibility) of adjacent regions of constant constant refractive index, abrupt magnification change of a divided multifocal lens and a typical image jump. ) And eliminate. The generally constant index region provides the power of the individual vision portions of the lens. The other layers of the lens have a constant or similar refractive index change.

  A multifocal spectacle lens is a visual aid used for the management of presbyopia in which the regulatory function of the eye has been partially or totally lost. The American Vision Council advocates multifocal brans as 'lenses designed to provide correction of two or more discrete distances'. Such bifocal and trifocal lenses are multifocal lenses and are distinguished from progressive addition lenses. And it is 'designed to provide correction of multiple viewing distances that vary continuously rather than discretely.' The first multifocal lens was the first bifocal lens invented in 1784 by Benjamin Franklin. With exceptions, bifocal lenses typically have one power correction for far vision and one power correction for near vision.

  On the other hand, a trifocal lens typically has one power of far vision, one power of intermediate vision, and one power of near vision. Some multifocal lenses are provided for specific purposes. The multifocal lens has an add power segment at the top of the lens, a distance vision correction at the bottom of the lens, a distance power at the top of the lens, and other powers ( Or their refractive power is reversed). The four-focal lens may take the form of a trifocal lens with a segment added to the top of the bifocal lens. Similarly, a 'double D' bifocal lens has a second bifocal segment on top of the lens.

  The bifocal segment has one of a variety of shapes: flat top, curved top, circular, rectangular, and 'executive'. The trifocal segment is commonly used on a flat top and is an 'executive' style. Like the bifocal segment, the trifocal segment is available in various heights and sizes. Flat top design is the most common type of bifocal. The segments are sized in the range of 25-40 mm with 28 mm being the most common segment. A curved top bifocal lens resembles a flat top in overall shape. However, the top of the segment is curved. The circular segment of the 'Kryptok' bifocal lens is less noticeable than the curved top bifocal segment.

  The near vision portion of the 'executive' bifocal lens includes the entire bottom section of the spectacle lens. And its entire bottom provides the largest near field of all bifocal lenses. In this regard, the 'executive' bifocal lens is most similar to the original Benjamin Franklin bifocal lens. It is also most effective for extended near field work that requires a wide field of view. There is an uncommon Ultex design today. The segment has a curved top, but includes the entire bottom of the spectacle lens, like an 'executive' bifocal. The segment top is common, but always located at the bottom of the lid edge, or a few millimeters below the lid edge, while the circular segment is eccentric with a 2-3 mm nasal sound to allow convergence Do not mean.

  Many of the bifocal lenses manufactured today are a plastic lens having an 'add' part formed integrally with the lens body. Due to the discontinuity of the surface profile that the two parts satisfy, the segment appears in the lens. The patient then notices an image jump or image shift (replacement) when viewing the object through different zones of the lens. In many cases there is a pronounced ridge with segments having a flat top. Fused glass bifocal and trifocal lenses are now less common than years ago. These lenses utilize two compatible glasses having different refractive indices. These glasses are melted together above 600 ° C. The high refractive index portion of the molten glass lens is also visible in the lens. There is also an image jump.

  Non-linear bifocal lenses or blended bifocal lenses attempt to visibly hide segments by blending regions that join different parts of the lens. Blended bifocal lenses have not gained a great reputation because the blended region has curvature curvature or deformation that causes blurring and distortion (distortion).

  In addition to bifocal and trifocal lenses, progressive addition lenses are used to provide multiple viewing distance corrections. Unlike bifocal and trifocal lenses, progressive lenses have a gradient that increases the lens power. The gradient provides a continuous focus range between near vision and far vision. The range of the power gradient is typically in the range of about 12-18 mm. Progressive lenses have a decorative appearance because there are no segment lines and visibility (visibility) present in bifocal and trifocal lenses.

  However, the effective area of the progressive and near vision zones of the lens is limited because aberrations resulting from lens power changes cause visual degradation, especially at the bottom of the side surface of the lens. As a result, some zones do not fit well with progressive lenses and are not preferred for reading glasses or for either bifocal or trifocal glasses lenses.

  Prior to the advent of plastic progressive lenses and blended bifocal lenses, designers used lenses to conceal segment lines by locally changing the refractive index at the interface between the segment lens and the carrier lens. An attempt was made to develop a multifocal lens having a refractive index gradient between the visual parts. For example, a segmented glass lens ion exchange method has been proposed for this purpose, as described in Hensler, US Pat. In order to create an ophthalmic lens with a power change in a locally concentrated region, the use of inorganic salts to change the refractive index of the porous glass has been proposed. Deeg et al. Discloses such a lens (Patent Document 2).

  None of the lens systems has been commercialized to date, due in part to the difficulties associated with each manufacturing process and the relatively small refractive index changes. Some of these methods may be effective for correcting optical aberrations. However, large refractive index changes are required to provide the power required for high diopter additions in bifocal and trifocal lenses.

  Gradient index plastic lenses have been proposed that are manufactured by diffusion or other methods.

  Blum et al., US Pat. No. 6,057,096 and Maeda et al., US Pat. The multifocal lens has a gradient resin layer between the first resin layer and the second resin layer. The interior has a curved segmented region that provides add power. The refractive index gradient varies in a range between the refractive index gradient of the first resin layer and the refractive index gradient of the second resin layer in the axial direction. Accordingly, the refractive index gradient of the multifocal lens creates a less abrupt transition (border / transition) between the first resin layer and the second resin layer, creating a more invisible final multifocal zone. Both of these lenses exhibit a positive power range, and exhibit their associated optical properties and aberrations.

  Naujokas, US Pat. No. 5,677, 315 describes a multifocal plastic ophthalmic lens. The lens has a uniform refractive index gradient between the upper and lower lens portions of different refractive indices. First, the lens can provide distant vision properties and near vision properties. The lens ray tracing according to the parameters described in this patent document 1 can achieve a diopter equivalent to 1 diopter only when a configuration with a fairly high power is used. It shows that.

  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 that describes the cylindrical power, the cylindrical power changes and causes aberrations as a result of the refractive index that changes gradually or gradually.

  Dreher, US Pat. No. 6,053,065 describes a multifocal progressive lens or progressive lens composed of a layer of an indicator 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 typical limitations of an aspheric progressive lens.

U.S. Pat. No. 3,542,535 U.S. Pat. No. 4,073,579 US Pat. No. 5,861,934 U.S. Pat. No. 4,944,584 U.S. Pat. No. 3,485,556 US Pat. No. 6,942,339

  Based on the foregoing description, it has been found that there is a need to provide a multifocal spectacle lens that solves the problems associated with each patent document and in particular improves the optical properties. The benefit is obtained from a multilayer lens having a refractive index change (refractive index changing portion). Its refractive index changing provides the power required for different distance visual points. Accordingly, it is a main object of the present invention to provide a multilayer multifocal lens. The multilayer multifocal lens includes at least one layer having a plurality of portions having different refractive indexes. The parts are combined along a refractive index blend, which provides a clear, unrestricted vision through the various parts of the lens.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. It has a refractive index blend at the interface of adjacent lens parts. The size of the interface is small and the interface is optimized with a profile in which the lens parts are joined invisible. And the effective lens area is not wasted.

  Another object of the present invention is to provide a multifocal spectacle lens that includes two layers: one layer having a refractive index changing portion and the other layer having a surface obtained according to a patient's prescription.

  Another object of the present invention is to provide a multifocal spectacle lens that includes two layers that effectively increases the refractive index difference and power difference between the visual points of the lens. Each layer has a refractive index change profile and a frequency (plus or minus) opposite to that of the other layer.

  Another object of the present invention is to provide a multifocal spectacle lens comprising three layers. Two adjacent layers have a refractive index change 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 multifocal spectacle lens having a refractive index change comprising two layers. Each layer has a refractive index change profile and a frequency with the opposite sign to the other layer. The refractive index blend of the refractive index change profile is either aligned or misaligned.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change comprising three layers. Two adjacent layers have a refractive index change profile and a power of opposite sign to the other layer. The third layer has a surface obtained according to the patient's prescription. The refractive index blend of the refractive index change profile is either aligned or not aligned.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. The lens has no visible segment edges.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change (part). The refractive index changing portion does not protrude (become trapped) from the intermediate vision segment and / or the near vision segment.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. All layers of the lens have a continuous curved surface.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. Each portion has a substantially constant frequency over its side surface range and roundness range. These ranges result in a large distance vision part, a near vision part, and an intermediate vision part (if present).

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. The lens does not have a width-limited corridor with a limited width of intermediate vision, and the intermediate vision portion and / or the near vision portion extends to the lateral boundary of the lens.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. A multifocal spectacle lens utilizes only a curved spherical surface on the surface of a layer having a refractive index change. The lens provides excellent optical properties.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. Multifocal eyeglass lenses utilize 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 multifocal spectacle lens having a refractive index change. The magnification is constant throughout the lens.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change. The lens is free of astigmatism and the visibility (vision) through all parts of the lens is clear and sharp.

  Another object of the present invention is to provide a multifocal spectacle lens having a refractive index change that includes multiple thin layers. Each layer includes a refractive index change profile and the opposite and sign power of an 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 multifocal spectacle lens having a refractive index change in the form of a doublet or triplet fullnel lens.

  Another object of the present invention is to provide a multifocal spectacle fullnel lens having a refractive index change. 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 multifocal spectacle fullnel lens having a refractive index change. The inclination of the non-optical functional steps (steps that are not optically functional) of the Furnell surface corresponds to several angles of the patient's gaze angle, thereby partially disturbing the ray from the object in the peripheral field of view. Limited. Therefore, the efficiency of the lens is increasing.

  Another object of the present invention is to provide a multifocal spectacle fullnel lens having a refractive index change. The shape of the lens is not flat, but rather curved like an eye. The tilt of the non-optical functional steps of the Furnell surface corresponds to the patient's gaze angle, so that it does not specifically disturb 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 multifocal spectacle fullnel lens having a refractive index change. The shape of the lens is not flat, but rather curved like an eye. The tilt of the non-optical functional step of the Furnell surface corresponds to several angles of the patient's gaze angle, thereby partially limiting the obstruction of light 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 method of manufacturing a multifocal lens having a refractive index change. The method includes a resin spray technique using dispersed particles, a resin mixing technique using dispersed particles, and diffusion.

  These objects and advantages and other objects and advantages are realized by a multifocal lens that has a continuous curvature and obtains an increased power of intermediate and / or near vision via a change in the refractive index of the lens. Due to the properties of the refractive index blend at the interface of such different refractive index portions, the lens of the present invention can provide improved vision and blended area. The blend area is very narrow (small) in vertical range or height and is virtually unperceivable.

  The lens of the present invention uses one or more refractive index changing layers constituting a multilayer lens. A changing refractive index profile corresponds to a plurality of regions of the lens. The region is oriented in the direction of refractive index transition transverse to the meridian of the lens and in the crosswise direction of the lens (bifocal lens, three Provides vision at two or more discrete distances (similar to a focal lens or other multifocal lens). The lens provides a distinct visual point in the overall vertical relationship and has a substantially constant refractive index from one surface of the layer to the other.

  The power required at several points on the lens is immediately and always effective via the refractive index changing layer. Thus, the lens has a minimum center thickness and a minimum edge thickness. For example, in one of the typical lenses, a 48 mm that provides a '0' power through the distance vision portion of the lens and an addition power of 2.5 diopters through the lens' near vision portion. The diameter lens is so thin that it has a center thickness of 1.76 mm and an edge thickness of 1.13 mm.

  The refractive index profile is optimized to provide an overall constant power for each lens section. For some given lens sizes, the extent (width) of the blend area defines the size of the optically functional vision part of a generally constant power connected by the blend area. Accordingly, the range of the blend region is narrow, and the blend region has a refractive index change rate. The rate of change of the refractive index is smooth and continuous and not irregular. The blend region is not activated to provide an intermediate zone of vision through the range because the range is smaller than that required to provide an effective optical function.

  From this point of view, the range of the blend should be as short as possible so that important and effective lens areas are not wasted. If the blend range is very small, the internal reflectivity may occur at an angle. And the part which can be perceived between the parts of a constant refractive index as a whole is brought about. The effective range of blends is in the range of 0.3-2 mm or more.

  The rate of change of the refractive index that defines the blend is typically maximal in order to perform (fill) its function of providing a non-visible interface between the visual points of the lens with a small blend range. The value should follow a half or sinusoidal curve of the local minimum (pi / 2 to 3pi / 2). Thus, the rate of change of refractive index change in the overall vertical direction is optimized for the lens. This type of blending is performed by many different processing methods.

  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 a compatible low refractive index optical material (having a refractive index of 1.3 to 1.5) together with one of the high refractive index optical materials mentioned above or other high refractive index optical materials, A refractive index change profile (changing reflactive index proffile) is obtained with a large refractive index difference suitable for use in accordance with the disclosure.

  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 straight path or arcuate path, is 0.3-2 mm wide or larger, and overlaps deposits Deposits having regions or common deposit regions are produced. In the overlapping part or common part, the amount of the substance sprayed from each spray gun changes. This smoothly changing composite mixture of two resins in this minimal common area (part) results in a corresponding refractive index change from the refractive index of one material to the refractive index of the other. . The composite resin material is polymerized chemically or with light, otherwise solidified.

  Various diffusion methods that affect the diffusion of optical monomers of different composites (compositions) and the refractive index in at least one direction across the interface are described, for example, in Naujokas US Pat. For large gradients with a sufficient range (eg 20 mm), these methods can be used. This is because some errors at the interface caused by poor processing methods are averaged over the length of the gradient. Further, the result does not cause optical aberration. However, for smaller width blend regions that are part of the present invention, greater control is required because it is used.

  To achieve this goal, two methods of optical resin diffusion are provided. The first method involves the use of 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. The second method involves 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, providing complete mixing and mixing of two adjacent liquids just below the interface. Once the particles have settled sufficiently, the liquid composition is polymerized chemically or with light, otherwise solidified.

  The lens disclosed herein may include two layers, three layers, or more 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 typical lenses, a reverse index change profile is used for adjacent plus and minus power layers to efficiently increase or double the index difference. Thereby, a high addition is achieved with a low curvature or a flat curvature, and a means for reducing the lens thickness is provided. At least one set of the inverse refractive index changing portions is required to increase the refractive index.

  For example, if the refractive index change profile defines a maximum refractive index difference of 0.3, (2) reverse changing refractive index layer (the high refractive index portion is the difference between adjacent negative power layers). (1) Changing refractive index 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 doubled to 0.6. This very large index difference is advantageously used in accordance with the present invention to provide high diopter add power in thin lens designs.

  In another embodiment of the present invention, a typical lens consists of a number of thin layers alternating with refractive index changing 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 bifocal or trifocal lens with sufficient add power. By using a plurality of refractive index changing layers alternately stacked in this manner, an effective refractive index difference can be 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 blended refractive index 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 multi-layer multifocal lens takes the form of a doublet Fresnel lens that includes one or two refractive index changing 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 changing layer thick enough to fill the open area of the short focus Furnell surface (e.g., 0.3-0.4 mm thick), the bifocal or trifocal lens of the present invention is simply Obtained with a thin lens configuration. Here again, the spraying technique described above provides an ideal method of applying a refractive index changing layer (thickness of 0.3-0.4 mm). The use of two new Furnell lenses offers increased efficiency and effectiveness.

  Lenses according to this disclosure 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 more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

1A, 1B, and 1C are side views schematically showing a first group (embodiment) of a multifocal lens. These multifocal lenses include one refractive index changing layer having a plus power in a doublet lens configuration including a concave inner surface, a flat inner surface, and a convex inner surface. FIGS. 2 (a), 2 (b), and 2 (c) are diagrams schematically showing a bifocal and a trifocal resin casting chamber including a dissolvable membrane for separating a resin portion. 3 (a) to 3 (f) are diagrams schematically showing examples of various multifocal lenses of the present invention. 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 rear curvatures against the inner curvature of the refractive index changing lens. 7 (a), 7 (b), 7 (c), and 7 (d) are diagrams schematically illustrating different orientation angles of the refractive index change lens layer. FIG. 8 is a side view schematically showing a second group (embodiment) of the multifocal lens. The multifocal lens includes one refractive index changing 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 multifocal lens. The multifocal lens includes a refractive index varying layer of the rear plus power in a doublet lens configuration including a concave inner surface. 10A, 10B, and 10C are side views schematically showing a fourth group (embodiment) of the multifocal lens. Each of these multifocal lenses includes one refractive index changing layer having a rear minus power in a doublet lens configuration 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 multifocal lens. These multifocal lenses include two refractive index changing layers in a doublet lens configuration that includes plus and minus power layers at both the front and back positions. FIGS. 12A and 12B are side views schematically showing a sixth group (embodiment) of the multifocal lens. These multifocal lenses include two refractive index changing 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 rear, and the third layer is the patient at both the front (Fig. 12 (b)) and the rear (Fig. 12 (a)). Has a prescription thus obtained surface, FIG. 13 is a side view showing a multifocal spectacle lens. The multifocal lens is in the form of a doublet Fresnel lens and contains a refractive index change. 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 multifocal spectacle lens. The multifocal lens contains a refractive index change in the form of an optimized doublet-Fnelnel 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 multifocal spectacle lens. The multifocal lens contains a refractive index change in the form of an optimized triplet Frunnel lens. The shape of the lens is curved like the patient's eye. FIG. 18A is a side view showing a multifocal spectacle lens. The multifocal lens contains a refractive index change in the form of an optimized doublet-Fnelnel 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 side view schematically showing a 14-layer bifocal lens having a large number of refractive index changing layers. FIG. 20 is a diagram showing an apparatus used to make a multifocal spectacle lens layer whose refractive index is changed by a spray technique. FIG. 21 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 this disclosure. 1 (a), 1 (b), and 1 (c) show the lens shapes of bifocal and trifocal lenses. The front lens portion A has a refractive index changing layer, and the rear lens portion B has a constant refractive index layer as a whole 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 of the near vision portion is larger than the refractive index of the far vision portion. Therefore, the addition power of the near vision part is provided.

  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. 1 (a) is used to explain the surfaces and layers shown in the three figures (FIGS. 1 (a)-(c)), and FIG. 1 (b) describes the part representing the bifocal lens. FIG. 1C is used to explain the portion representing the trifocal lens.

  Referring to FIG. 1B, the bifocal lens layer A is composed of an optically transparent material having two portions having different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index value N1 and the refractive index value N2 are generally constant refractive index values. The broken line 2 represents the refractive index blend interface between the refractive index value N1 and the refractive index value N2. Similarly, FIG. 1C shows a trifocal lens.

  The trifocal lens layer A is composed of an optically transparent material having three portions having different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the intermediate visual acuity part of the lens and has a refractive index value N2. A3 corresponds to the near vision portion of the lens and has a refractive index value N3. The refractive index value N1, the refractive index value N2, and the refractive index value N3 are generally constant refractive index values. A broken line 2t represents the refractive index blend interface between A1 and A2. The broken line 3t represents the refractive index blend interface between A2 and A3.

  1A, 1B, and 1C, the rear lens portion B is made of an optically transparent material. The refractive index N4 of the material is generally constant. The front surface 4 of the front lens part A has a curvature with a radius value R1. The internal interface I has a curvature (internal curved interface) R2. The rear surface 5 of the rear lens part B has a 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 refractive index blend interface 2 in FIG. 1 (b) and the refractive index blend interfaces 2t and 3t in FIG. 1 (c) as well as all other refractive index blend interfaces in the following embodiments and examples Has a profile. Its refractive index profile is from a low refractive index value equal to the low refractive index value of an adjacent part having a low refractive index value (far vision part), and an adjacent opposite part having a high refractive index value (near vision part). To a high refractive index value equal to the high refractive index value. The refractive index change profile has a smooth and regular rate of change. The ratio is generally characterized along the range (degree, width) so as to correspond to the position of pi / 2 to 3 pi / 2 of the sine wave curve or sine wave curve. Yes.

  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, one of the methods for the method of diffusion of one monomer among partially polymerized monomers or gelled monomers having different refractive indices to provide refractive index gradients having different values of high refractive index. One. Mutual solubility or miscibility and interdiffusion penetration of low viscosity monomers in high viscosity gelled "prepolymers" combine heat and duration (time) to determine diffusion and refractive index gradient depth Factors. 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 the refractive index blend region of the present invention is minimal over that range (about 0.3-2 mm or more) (first problem). Because of that fact, it is very important that the interfaces of the separate refractive index portions have a regular or 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. Interfacial deformation that exists prior to diffusion creates refractive index blend aberrations upon completion of the diffusion process. Whatever process is used to make the refractive index blend, the interface generally has a planar dimension in a direction perpendicular to the length of the interface, i.e., planar, cylindrical, elliptical, through the lens. It has a non-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, slight disturbance at the interface is caused by the movement of the separator. In particular, the refractive index change profile is detrimental when the separator is lifted from the liquid.

  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. 2 shows a molding chamber for an 'executive' type bifocal 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. 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 thereof may be smaller than the density 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, a blend interface of 0.3-2 mm or more is created and the lens resin is fully polymerized by either photopolymerization or catalytic polymerization.

  Similarly, FIG. 2B shows an 'executive' type trifocal lens having a rounded refractive index blend interface at the lower near vision portion. The membrane M2 is sandwiched between a lens chamber portion S3 that manufactures the resin refractive index portion N1 and a lens chamber portion S4 that manufactures the resin refractive index portion N2. The membrane M3 is sandwiched between a lens chamber part S4 that manufactures the resin refractive index part N2 and a lens chamber part S5 that manufactures the resin refractive index part N3. The resin refractive index portions N1 and N3 include a far vision portion and a near vision portion of the lens, respectively. N2 includes an equal mixture of the resin refractive index portion N1 and the resin refractive index portion N3. Thereby, an intermediate refractive index and an intermediate vision portion of the lens are obtained.

  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. Furthermore, the chamber is turned upside down as shown in FIG. 2 (c) so that the remaining bubbles do not remain in the central region of the recess in the membrane M3 (which faces down in FIG. 2 (b)). May be used. As a result, the remaining bubbles rise upward on the left and right sides of the molding chamber along the curvature of the membrane M3 and head toward the filling ports P3, P4 and P5. These areas are outside the area of the optical part of the lens.

  An additional (further) way to facilitate and speed up the production of refractive index blends is the controlled mixing of resin or monomer solutions of different refractive indices in a container or molding chamber (eg, a membrane-containing molding chamber as described above). Is included. 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. 21 is a diagram schematically showing this process using molding chambers arranged in the vertical direction. In FIG. 21, 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 at the center 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. 2 (b), 2 (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 solution, 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 configuration (laminated 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.

  Multi-point lenses including bifocal, trifocal and quadrufocal may be manufactured by such methods. For example, by using 0.01 gm of 5 micron diameter glass beads per 10 gms of 25 mm high resin, control, complete mixing and blending can be achieved with an original interface over a specific short distance defining the index blend range. It occurs just below. Once the particles have sufficiently settled in the liquid for a period of 15 hours or more, the composition is polymerized chemically or with light.

  Conversely, particles having a density less than that of the resin used to mold the lens are dispersed in the bottom layer solution. The resin then rises in solution due to buoyancy and similarly produces a refractive index blend interface. The particles rise above the chamber outside the effective area of the lens body. The rising and / or settling particles are used to produce a refractive index blend. This method is used in molding chambers or molding chambers with or without the membrane system described above.

  In FIGS. 1 (b) and 1 (c), the refractive index blend lines 2, 2t, 3t are located at different levels of the lens as shown in the Y direction shown in FIG. 1 (a). . The dashed lines shown represent the refractive index interface at the top surface of the bifocal and trifocal portions of the lens. When the near vision part or the intermediate vision part has a curved interface, the broken line represents the highest point of the curved part with respect to the horizontal line. In the case of a flat top or “executive” type interface, the dashed line corresponds to the level straight across the top of the interface.

  As an example of the different levels of the blend line, the bifocal blend line 2 in FIG. 1B is located 6 mm below the center line CL. It provides a bifocal interface corresponding to a level approximately 2 mm below the patient's eyelid margin. Similarly, the trifocal blend lines 2t and 3t are located at different positions with respect to the center line CL. However, in general, for the trifocal lens of the present invention, better performance is achieved with a somewhat smaller downward gaze (eg, a dashed line 2t at a distance 3mm below the center line CL and a dashed line 3t at a distance 7mm below the dashed line 2t). In order to introduce the intermediate vision portion of the lens, it is obtained by a broken line 2t that has moved slightly upward relative to the broken line 2 in FIG. As with prior art multifocal lenses, the segment positions of the present invention may vary greatly based on lens design and application.

  3A-3F show the six most common types of bifocal and trifocal lens configurations. Those lenses are manufactured according to this disclosure. In the figure, the portions indicated by A1, A2, and A3 and B are called the visual acuity part of the lens as defined in relation to FIGS. 1 (b) and 1 (c). FIG. 3A shows an “executive” type bifocal configuration. The refractive index blend interface is straight or substantially across the lens in the horizontal direction. FIG. 3 (b) shows a round topped type similar to the bifocal configuration of FIG. 3 (a) except that the index blend interface is curved towards the near vision portion of the lens. A bifocal configuration is shown. Thereby providing an additional visual area for distance vision in the lateral direction of the lens.

  FIG. 3 (c) shows an “executive” type bifocal configuration similar to FIG. 3 (a). However, it has a lens part A having refractive index change profiles A1 and A2 and a lens part B having refractive index change profiles B1 and B2, arranged in opposite directions. As a result, as will be described later with reference to FIGS. 11A and 11B, a high refractive index difference and a high addition are realized with a thin lens design. FIG. 3D shows an “executive” type trifocal configuration. It contains two refractive index blends in one part or one layer of a lens as shown in FIG. 1 (c).

  FIG. 3E shows a four-focal lens including four parts. The four parts are composed of a lower three part that provides a trifocal function and a top part that provides a second intermediate vision part above the far vision part. This lens shares the advantages of a curved refractive index blend of the lower and upper portions and the “executive” type flat top of the intermediate vision section. FIG. 3 (f) shows another lens having two bifocal lens portions A and B having a refractive index change. In this lens, the refractive index blend of each bifocal lens part A, B is not aligned with the lower blend of lens part B than the blend of lens part A. As a result, as shown in FIG. 11B, a trifocal lens having an intermediate vision portion including A2 and B1 is manufactured.

  FIG. 4 is a table showing related values of the spherical curvatures R1, R2, and R3. They show examples of lenses 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 intermediate power for a trifocal lens is 1.25 diopters. The add power and all other add powers described in this disclosure 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.

  The lens of the present invention requires modifications such as laboratory work when processed according to the patient's prescription. 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 1

Bifocal: Trifocal:
N1 = 1.46 N1 = 1.46
N2 = 1.7 N2 = 1.58
N4 = 1.58 N3 = 1.70
N4 = 1.58

  As described above, there are additional constants related to 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 "0" power of the distance vision portion. 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 the lens of the present invention. 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 of the present invention 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 of the present invention that each lens requires an additional bulk or “convex surface” to provide an add power due to the refractive index change 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 2

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 having a very high refractive index and an optical resin component having a very low refractive index together to create a refractive index change profile of 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 refractive index changing 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 change profile. The RID value of the lens is increased by a factor of 2 according to the method of the present invention. That is, it is increased to the maximum value of the refractive index difference between the two resin components (eg, 0.64) by the means fully discussed below.

  FIG. 5 is a table showing the CREN values of the lens of the first embodiment according to the RID of the refractive index changing 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 represents a group of lenses that are particularly suitable for use (although at intermediate efficiency) among the refractive index changing lenses of the present invention.

  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. 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. In the case of having a high CREN value, when the volume (bulk) is increased, the curvatures R1 and R3 are steep even if the radius of the inner convex interface is provided. 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 add lens with 0.16 RID and a CREN value of 41.18 is The curvature is considerably 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 with the refractive index changing, or the maximum RID of the lens if only one lens layer contains the refractive index change. 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 refractive index change profiles in the opposite direction to increase RID and decrease CREN value. In such cases, values beyond the first line and up to "approximate maximum RID of the lens" can be applied. Instead, when the two reverse refractive index changing layers are made of a material having a more moderate refractive index, so that each RID value is smaller than the RID value of the lens layer A in the lens of FIG. The RID may exceed the RID of a lens having only one refractive index changing layer having the maximum 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 means the CREN value equation described above. The equation converted to surface diopter is shown below.

Formula 3

  D1 + 2 ・ D2 + D3 = CREN

  Further, the properties of the lens of the present invention will be described. Of course, when the refractive index values N1, N2, and N3 are different from the refractive indices of the example lenses, the correlated values shown will change.

  As mentioned above, excellent optical properties 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 a lens of the present invention having an 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 modified versions of the lens of the first embodiment. 7 (a) to 7 (d), the orientation angles X of the refractive index blend are different. The orientation angle of the refractive index blend means an angle that defines at least a portion of a surface (eg, a plane). This surface intersects a refractive index blend that is a substantially constant refractive index. By properly selecting the orientation angle of the refractive index blend, the vision through the refractive index blend of the lens at the 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 line of sight tilts diagonally at an angle where the refractive index is not constant throughout the blend. 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 blend 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 refractive index blend 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 through the surface area of the lens through which the bundle of light passes at a substantially normal (orthogonal) angle.

  A second method for obtaining a positive refractive index blend orientation angle is as shown in FIG. 7 (c) when the patient looks through the refractive index interface of the lens. Inclining the refractive index interface in the lens medium to approach the corner and respond. The orientation angle X consists of two angles as shown in FIG. Each of the two angles corresponds to approaching the patient's gaze angle as the patient views through the two refractive index interfaces of the bifocal lens. A desired refractive index blend orientation angle can be obtained by combining the inclination of the refractive index interface in the medium with the lens and the forward inclination of the lens.

  The pupil of the eye is not a point, but rather covers an average area of 4 mm 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 optimizing the refractive index blend orientation angle. This is relatively important when the refractive index change and refractive index blend includes only the plus power portion of the lens, as shown in this embodiment. In this case, the patient staring straight ahead sees the thickest part of the refractive index change part. This is also relatively unimportant when the refractive index changing portion includes only the minus power portion of the lens. In this case, the patient staring straight ahead is looking at the thinnest part of the refractive index change part. As mentioned above, an embodiment of a negative power refractive index change is shown in FIG.

  FIG. 8 shows a configuration of a doublet lens according to the second embodiment of the present invention configured according to this disclosure. The front lens part A has a changing refractive index layer of the lens, and the rear lens part B has a generally constant refractive index layer 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 R <b> 2 is concave with respect to the front lens portion A. In this lens, the refractive index of the far vision portion is larger than the refractive index of the near vision portion. Therefore, it provides the addition power of near vision.

  With regard to the bifocal and trifocal lenses shown and described in detail in the first embodiment, it should be understood that a number of multifocal designs are provided by the present invention. Thus, only one refractive index change profile is mentioned here (including two parts of a generally constant refractive index). It is further mentioned in the examples and embodiments. It is understood that the present invention is not limited to a bifocal design or some specific other multifocal designs.

  With reference to FIG. 8, the lens layer A is composed of an optically transparent material having two portions with different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2.

  The rear lens part B is made of an optically transparent material. The refractive index N3 of the material is generally constant and does not change. 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 shown by the dashed line 2, a refractive index orientation angle of 8 ° is obtained by tilting the refractive index interface in the medium of the lens body.

  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 this example lens and all the following example lenses, the orientation angle of the refractive index blend is denoted OA. Typical values of the parameters of the three bifocal lenses according to this embodiment are shown below.

  FIG. 9 shows the structure of a doublet lens according to the third embodiment of the present invention. The front lens portion A includes a generally constant refractive index layer of the lens, and the rear lens portion B includes a refractive index changing layer of the lens. The internal interface I is indicated by I on the right side. 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 of the near vision part is larger than the refractive index of the far vision part. Therefore, it provides the addition power of near vision.

  As illustrated in the illustrated examples and embodiments described above, the lens layer B has two parts with different refractive index values to be described using similar conventions that identify and define the lens. Consists of optically transparent material. B1 corresponds to the distance vision portion of the lens and has a refractive index value N1. B2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2.

  The front lens portion A is made of an optically transparent material. The refractive index N3 of the material is generally constant and does not change. 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 indicated by dashed line 2, a refractive index orientation angle of 8 ° is obtained by tilting the lens with respect to the patient's gaze angle.

  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. 10A, 10B, and 10C show the configurations of three doublet lenses according to the fourth embodiment of the present invention. 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 refractive index changing portion of the lens. The front lens part A has a positive power and the rear lens part B has a negative power.

  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. In this embodiment, the refractive index of the far vision part is larger than the refractive index of the near vision part. Therefore, it provides the addition power of near vision.

  FIG. 10A shows an embodiment in which the internal curved interface R2 is concave with respect to the lens part A. FIG. FIG. 10B shows an embodiment in which the internal curved interface is a plane. FIG. 10C shows an embodiment in which the internal curved interface is a convex surface with respect to the lens portion A. FIG.

  In FIG. 10B, the bifocal lens layer B is composed of an optically transparent material having two portions having different refractive index values. B1 corresponds to the distance vision portion of the lens and has a refractive index value N1. B2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2. Thereby, the refractive index orientation angle obtained by tilting the lens by 8 ° with respect to the gaze angle of the patient is represented.

  The front lens portion A is made of an optically transparent material. The refractive index N3 of the material is generally constant and does not change. 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. The lens shown in FIG. 10C has an angle obtained by combining the inclination of 4 ° forward of the lens with the inclination of 4 ° of the refractive index interface in the lens medium. Thereby, a total orientation angle tilt of 8 ° is provided.

  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 three bifocal 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. 11A and 11B show the configuration of two doublet lenses according to the fifth embodiment of the present invention. In these embodiments, only one figure is used to describe the range of possible shapes. It can be understood from the above-described embodiments and examples that lenses having convex, planar, and concave internal interfaces are included in the present invention. In these lenses, both the front lens portion A and the rear lens portion B include a refractive index changing portion of the lens. By using a pair of inverse refractive index change profile 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 layer that changes the refractive index. Thereby, as will be seen in the following embodiments and examples, it provides a means of obtaining a high addition with a low curvature or a flatter curvature and minimizing the lens thickness.

  In FIG. 11A, the lens part A has a positive power and the lens part B has a negative power. In this lens part A, the refractive index of the near vision part is larger than the refractive index of the far vision part. In this lens part B, the refractive index of the far vision part is larger than the refractive index of the near vision part. Thus, it provides a power addition to near vision.

  The lens layer A is composed of an optically transparent material having two parts having different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole.

  The lens layer B is composed of an optically transparent material having two portions having different refractive index values. B1 corresponds to the distance vision portion of the lens and has a refractive index value N3. B2 corresponds to the near vision portion of the lens and has a refractive index value N4. The refractive index N3 and the refractive index N4 are generally constant refractive index values.

  In FIG. 11 (a), the refractive index blends 2, 3 of the lens portions A, B are aligned to provide a coordinated distance vision and near vision portion of the lens. (Adjusted). By that alignment, it is meant that the surfaces defining the orientation angles of the two refractive index blends corresponding to a portion such as an interface generally coincide.

  The refractive index blend orientation angle (OA) of the lens of this example is 8 °. It is obtained by tilting the refractive index interface in the medium of the lens body. 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, R3 represented in the example lenses having concave, planar and convex internal curved interfaces are the combined CREN values, refractive index values (N1-N4), lens thickness (CT, ET) and optical conic constant values (CC) are shown in the table below. 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.

  In FIG. 11B, the lens part A has a minus power and the lens part B has a plus power. In this lens part A, the refractive index of the far vision part is larger than the refractive index of the near vision part. Further, in the lens part B, the refractive index of the near vision part is larger than the refractive index of the far vision part. Thus, it provides a power addition to near vision.

  The lens layer A is composed of an optically transparent material having two parts having different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the intermediate vision portion and the near vision portion of the lens, and has a refractive index value N2. The refractive index value N1 and the refractive index value N2 are generally constant refractive index values.

  The lens layer B is composed of an optically transparent material having two portions having different refractive index values. B1 corresponds to a distance vision portion and an intermediate vision portion of the lens, and has a refractive index value N3. B2 corresponds to the near vision portion of the lens and has a refractive index value N4. The refractive index N3 and the refractive index N4 are generally constant refractive index values.

  In FIG. 11 (b), the refractive index blends 2, 3 of the lens portions A, B are not aligned to provide a region of the intermediate vision portion between the two refractive index blends. By not being aligned, it means that the planes defining the orientation angles of the two refractive index blends corresponding to a part such as an interface do not coincide and are parallel or intersect in the line.

  Two refractive index blends of adjacent lens portions may not be aligned such that one refractive index blend is positioned above or below the level of the other refractive index blend of adjacent lens portions. In FIG. 11B, the refractive index blend 3 of the rear lens portion B is disposed 7 mm below the refractive index blend 2 of the front lens portion A. Thereby providing an intermediate vision region with a vertical range of 7 mm.

  The orientation angle (OA) of each refractive index blend interface 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, R3 represented in the example lenses having concave, planar and convex internal curved interfaces are the combined CREN values, refractive index values (N1-N4), lens thickness (CT, ET) and optical conic constant values (CC) are shown in the table below. 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) show the configuration of two triplet lenses of a sixth embodiment of a lens type made according to this disclosure. In these embodiments, only one figure is used to describe the range of possible shapes. The lenses of FIGS. 12 (a) and 12 (b) have the same characteristics as the lenses of the fifth embodiment of FIGS. 11 (a) and 11 (b). Both the front lens part A and the rear lens part B include a refractive index changing 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 (FIG. 12A) is made of an optically transparent material whose refractive index N5 is generally constant and does not change.

  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 has a sufficiently thick lens part C processed according to the patient's prescription. The final center thickness of the lens portion C is about 0.25 mm. The correlation values for R1, R2, R3, and R4 of the two example lenses with various internal curved interfaces R2 are the combined CREN value, refractive index value (N1-N5), lens thickness (CT, ET) And the optical conic constant value (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 4

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 the addition power of the lens. Is preferred. 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 minimize lens thickness and volume, the center thickness of the lens portion C is preferably 0.25 to 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 change 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 described above. The lens has only one lens part including the refractive index changing part of the lens.

  Accordingly, it is understood that the lens shown in FIGS. 11 and 12 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 change. The 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. 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 further embodiments of lenses according to this disclosure. These figures have a multilayered Fresnel lens having a refractive index change. As described above, the surface of the Furnel lens has a large number of discontinuous coaxial annular portions. The multiple discontinuous coaxial (concentric) 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 a lens such as a transparent Victorola Record (registered trademark) is attached.

  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 surrounding field have good contrast and clarity when staring at an angle through the left, right and lower near vision portions 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 Is somewhat reduced.

  When the patient is looking straight ahead, the pupil is located approximately 16 mm behind 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 a fullnel lens according to this disclosure is to bond the lens layer adjacent to the fullnel surface of the fullnel preform as a cast layer. . The molding layer is formed to be, for example, the layer A in FIG. This removes or limits all the full-Fnelnel diffraction and reflection 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 the other parts The reflection and diffraction are almost reduced. When the refractive index of the bonded part is equal to the refractive index of the fullnel preform, not only the function of fullel, 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, the refractive index of the combined part (combined addition part) providing the add power, for example by using a high power fullnel preform of either 20 diopters plus or minus power. Can be somewhat closer to the value of that 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. The index of refraction of the combined add power portion is either plus or minus depending on whether the Furnell 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 structure of a doublet Flennel lens defining the lens of the seventh embodiment obtained according to this disclosure. In the lens shown in FIG. 13, the non-optical function step (stepped surface) is normal to the lens shape. And that step does not match the described exit pupil. In FIG. 13, the lens portion A constitutes a generally constant refractive index portion of the lens, and the lens portion B constitutes a refractive index changing 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 of the distance vision of the lens part B is smaller than the refractive index of the near vision. Thus, it provides a power addition to near vision.

  The thickness of the lens part B is minimal, and therefore the refractive index blend angle represented by the dashed line 2 is also minimal (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.

Formula 5

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 Furnell's diopter curved shape (R2f), which is independent of its actual surface power.) For lenses where the refractive index of the layer portion with the change (eg, distance vision portion) is the same as the refractive power of the full-nell preform to which it is joined, curvature correction is not required for R1 and R3, such as In some cases (whether R2 is flat or curved), R1 and R3 may be “parallel” to the shape or contour (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 6

  4-8 + 4 = 0

  When R1 and R3 are not parallel to R2, for example, when 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 four example full-lens lenses.

  In FIG. 13, the lens layer B is made of an optically transparent material having two portions having different refractive index values. B1 corresponds to the distance vision portion of the lens and has a refractive index value N1. B2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2.

  The front lens portion A is a fullnel preform lens made of an optically transparent material. The refractive index N3 of the optically transparent material is constant as a whole. 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 zero power in the distance vision portion of the lens and high diopter addition power in the near vision portion of the four lenses, 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, the point E located approximately 21 mm after 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 N3 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. Molded Furnell layer B includes a refractive index N1 of 1.491 and a refractive index N2 of 1.58. The lens provides an add power 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, and in this case, the surface shape of the Furnell interface becomes invisible. 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 FIGS. 15 and 16, there is no obstruction or cutting 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 mentioned above, the annular fullnel step is optimized for the exit pupil at a position 21 mm behind 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. As shown in FIG. 17, this lens is similar to the lens described in FIG. However, this lens includes a third lens layer C which forms a triplet Frunnel lens. 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 as shown in FIG. 13 or are angled and corrected as shown in FIG. . Both of them have been described above.

  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 changing 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 of the far vision part of the lens part B is smaller than the refractive index of the near vision part. Therefore, it provides the power of near vision.

  Since the thickness of the lens portion B is the smallest as in the full-lens lens of the embodiment described with reference to FIGS. 13 to 16, there is no refractive index orientation angle. Thus, the thickness of the refractive index blend represented by dashed line 2 is also minimal (about 0.35 mm). The lens layer B has two parts with different refractive index values. The 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 and has a refractive index value N1. B2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2.

  The front lens portion A is a fullnel preform lens made of an optically transparent material. The refractive index N3 of the optically transparent material is constant as a whole. The rear lens layer C is a preform lens having a refractive index N4. The inner surface 5 of the lens part C has a curvature R3 that may be flat or slightly convex with respect to the lens part C in order to promote the bubble-free joining with the refractive index change of the lens part B. Yes. 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 changing portion of the lens is provided in one or both lens portions as in the above-described embodiment of the present specification. However, it is preferable that only one refractive index changing portion includes a refractive index changing profile of a bifocal full-length lens. A trifocal lens may include a single layer having two refractive index blends. As described above, each part having a distinct power provides the visual of the corresponding visual zone. Alternatively, an embodiment similar to the lens of the fifth embodiment may provide three parts with distinct powers for the corresponding visual zone. In the lens, both refractive index changing portions contain refractive index changes, and the refractive index blend interface 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 refractive index changing 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 (modulo A larger curved lens may be provided so as to be normal. 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 FIG. 18, the exit pupil E is located 28.5 mm after the rear surface of the spectacle lens. The lens part A includes a refractive index changing part of the lens, and the lens part B includes a generally constant refractive index part 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 of the far vision part of the lens part A is larger than the refractive index of the near vision part. Therefore, it provides the power of near vision.

  Referring to FIG. 18, the lens layer A is composed of an optically transparent material having two portions with different refractive index values. A1 corresponds to the distance vision portion of the lens and has a refractive index value N1. A2 corresponds to the near vision portion of the lens and has a refractive index value N2. The refractive index N1 and the refractive index N2 are constant refractive index values as a whole. The broken line 2 represents the refractive index blend interface between the refractive index N1 and the refractive index N2.

  The rear lens part B is a fullnel preform lens made of an optically transparent material. The refractive index N3 of the optically transparent material is constant as a whole. 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 an equivalent 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.

  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 changing portion of the planar shape Fresnel lens of FIGS. 13, 15, and 17 may be manufactured using a spraying method as described above. In that method, two spray guns (S1 and S2 in FIG. 20) are used. The spray guns move together along a straight or arcuate path. In such a state, each spray gun has a deposit of 0.2 to 2 mm wide or beyond the range of the lens (a deposit such as a stack of resin sprayed from two guns or a common one). Spray one of the refractive index resins onto the surface of the Furnell preform. 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 separates the distance vision portion and the near vision portion. And from each gun in those adjacent parts, controlling the amount of resin sprayed over the separation vertical wall and through the bottom of the separation vertical wall to mix the sprayed adjacent resin parts Prevents unwanted spray from accumulating. The extent of the overlap region or blend region may be increased or decreased. The range is easily controlled by the height of the separation wall, the spray direction of the gun, and the spray pattern.

  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.

  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 connected part. 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 change portion of the curved doublet Furnell lens of FIG. 18 (a) is produced in a similar manner using two gun spray systems that produce a refractive index blend region composition. In this case, the resin is flexible at a desired thickness (eg, 0.35 mm thickness) and is deposited on the flat surface of the molding element. Once deposited, the resin may be partially polymerized into a gel. Following this stage, the molding element is bent so that its surface ensures a curvature (curvature) corresponding to a full-nell preform. The partially gelled polymer is then pressed against the preform and polymerized to permanently bond the gelled layer to the Furnell surface.

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

  FIG. 19 shows an eleventh embodiment lens constructed in accordance with this disclosure. The lens in FIG. 19 is a multifocal spectacle lens. The lens has multiple layers with multiple refractive index changes and power signs. Each frequency code is opposite to the frequency code of the adjacent layer. As already described, a set of refractive index change 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 addition with low or plane curvature and 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 the corresponding addition.

  For example, at the opposite power, if one pair of opposite profile layers provides 0.417 diopters of add power, six identical pairs of layers provide 2.5 diopters of add power. In FIG. 19, the front lens part A has a constant refractive index as a whole, and the lens part B, the lens part C, the lens part D, and the lens part E have a changing refractive index. 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. The refractive index of the far vision part of the lens part C is larger than the refractive index of those near vision parts. Moreover, the refractive index of the distance vision part of the lens part D is smaller than the refractive index of those near vision parts. Thus, it provides a complex addition power for near vision.

  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 composed of an optically transparent material having two portions having different refractive index values. B1 corresponds to the distance vision portion of the lens and has a refractive index value N2. B2 corresponds to the near vision portion of the lens and has a refractive index value N3. The lens layer C is composed of an optically transparent material having two parts having different refractive index values. C1 corresponds to the distance vision portion of the lens and has a refractive index value N4. C2 corresponds to the near vision portion of the lens and has a refractive index value N5.

  The lens layer D is composed of an optically transparent material having two parts having different refractive index values. D1 corresponds to the distance vision portion of the lens and has a refractive index value N6. D2 corresponds to the near vision portion of the lens and has a refractive index value N7. The lens layer E is composed of an optically transparent material having two parts having different refractive index values. E1 corresponds to the distance vision portion of the lens and has a refractive index value N8. E2 corresponds to the near vision portion of the lens and has a refractive index value N9. The broken line 2 represents the refractive index blend interface of N2 and N3, N4 and N5, N6 and N7, and N8 and N9.

  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 curvature of adjacent internal interfaces is opposite, the CREN value of a lens according to this embodiment is simply calculated by adding the full surface power of all surfaces.

  As shown in FIG. 19, a refractive index orientation angle of 8 ° is obtained by not aligning increasing amounts of a continuous refractive index blend. 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 bifocal 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. 20 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 combine overlapping deposits having a width of 0.3 to 2 mm. Or produce a combined common deposit.

  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 easily controlled by the height of the separation wall W, the distance from the deposit to the spray gun, the spray direction of the gun, and the shape of the spray pattern. A separation wall height above 3 mm of the sprayed deposit results in a blend of about 1 mm width. As the deposit layer is obtained and its height increases, the separation wall W may be raised or the lens lowered to maintain an appropriate distance of the separation wall W from the top surface of the deposit. Also good. 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. 20, 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 then provides compression to push 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. 20, 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 (gradual) correction value to obtain a refractive index orientation angle of 2.

  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 changing portion or the plurality of refractive index changing 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 multifocal eyeglass lens for use by viewers,
The multifocal spectacle lens is 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 and has two adjacent portions and a blend region;
The two adjacent portions are composed of a first portion having a substantially constant first refractive index and a second portion having a substantially constant second refractive index,
The blend region extends transversely to the meridian of the multifocal lens and forms a transition between the two adjacent portions;
The transition has a refractive index that continuously varies between the first refractive index and the second refractive index, and has a very narrow width to provide an effective visual zone. The multifocal spectacle lens characterized by the above.   The multifocal spectacle lens according to claim 1, wherein each of the two layers has a continuous curved surface.   The multifocal spectacle lens of claim 1, wherein the other of the two layers is a second layer and is combined with the first layer to provide a vision correction prescription layer. 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;
The multifocal spectacle lens according to claim 3, wherein the first zone of vision and the second zone are selected from the group consisting of a far vision zone, an intermediate vision zone, and a near vision zone. . The two layers constitute a Furnell lens, and have an interface between the two layers,
The multifocal spectacle lens according to claim 1, wherein the interface between the two layers constitutes a Furnell surface. The Furnell surface has a plurality of optically non-functional steps, at least some of which are conical steps, the conical steps have a conical apex, and the multifocal spectacle lens has a rear surface. Have
The apex of the cone of the conical step is located behind the rear surface of the multifocal spectacle lens;
6. The multifocal spectacle lens of claim 5, thereby providing increased light transmission from a peripheral region point to the patient's eye through the multifocal spectacle lens.   The multifocal spectacle lens according to claim 6, wherein the apex of the cone of the conical step is located at 16 to 28.5 mm after the rear surface of the multifocal spectacle lens. The other of the two layers is a second layer,
The second layer is a layer having a substantially constant refractive index,
The multifocal spectacle lens according to claim 5, wherein the substantially constant refractive index is substantially the same as a refractive index of the first portion of the first layer. The other of the two layers is a second layer,
The second layer has two adjacent portions and a blend region;
The two adjacent portions are composed of a first portion having a substantially constant first refractive index and a second portion having a substantially constant second refractive index,
The blend region extends transversely to the meridian and forms a transition between the two adjacent portions;
The transition has a refractive index that varies continuously between the first refractive index and the second refractive index, and has a very narrow width to provide a visual effective zone. ,
The first layer has three parts including the first part, the second part, and the transition part,
The second layer has three parts including the first part, the second part, and the transition part,
2. The multifocal spectacle lens according to claim 1, wherein the first layer and the second layer are arranged with each other in any one of the following positional relationships (a) or (b).
(A) at least a portion of the three portions of the first layer having a low refractive index is at least a portion of the three portions of the second layer having a high refractive index; Are aligned along.
(B) at least a portion of the three portions of the first layer having a high refractive index is at least a portion of the three portions of the second layer having a low refractive index; Are aligned along. The multifocal spectacle lens further has a third layer,
10. The multifocal spectacle lens of claim 9, wherein the third layer is shaped to provide a vision correction prescription layer in combination with the first layer and the second layer. The first layer has a front surface and a rear surface that generally traverse the line of sight of the patient through the multifocal spectacle lens;
The transition portion has a range between the front surface and the rear surface,
2. 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 multifocal spectacle lens. The multifocal spectacle lens described. The first portion and the second portion of the first layer are a low refractive index portion or a high refractive index portion,
The other of the two layers is a second layer, and has a low refractive index portion, a high refractive index portion, and a transition portion between the low refractive index portion and the high refractive index portion. ,
The multiple transition according to claim 11, wherein the transition portion of the first layer and the transition portion of the second layer have a positional relationship of any one of the following (a) and (b). Focus glasses lens.
(A) a first arrangement including the low refractive index portion of the first layer and the high refractive index portion of the second layer; the high refractive index portion of the first layer; and the second layer. It is substantially aligned along the line of sight through the multifocal spectacle lens so as to form a second arrangement including the low refractive index portion of the layer.
(B) a first partial arrangement including the low refractive index portion of the first layer and the high refractive index portion of the second layer; the high refractive index portion of the first layer; and the second layer. A second partial arrangement including the low refractive index portion of the layer, and any one of the following a) or b), and the transition portion of the first layer and the second layer Correction is made to form a third partial arrangement with the transition.
a) The low refractive index portion of the first layer and the low refractive index portion of the second layer.
b) The high refractive index portion of the first layer and the high refractive index portion of the second layer. Each of the first layer and the second layer has an anterior surface and a posterior surface that generally traverses the patient's line of sight via the multifocal spectacle lens;
The transition portion has a range between the front surface and the rear surface,
13. 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 multifocal spectacle lens. The multifocal spectacle lens described. A method of making a lens that includes a first portion having a first refractive index and a second portion having a second refractive index, comprising:
Providing a mold;
At least one of a first solution and a second solution for separating the mold into a first region corresponding to the first portion and a second region corresponding to the second portion. Using a membrane that dissolves in
Filling the first region with the first solution and filling the second region with the second solution;
At least partially dissolving the membrane in at least one of the first solution and the second solution;
And then smoothing between the first portion having the first refractive index, the second portion having the second refractive index, and the first refractive index and the second refractive index. Curing the first solution and the second solution to form a solid having an index of refraction that changes to an intermediate portion between the first portion and the second portion. The method comprising the steps of: Using the membrane is using a membrane to form a boundary between the first region and the second region;
15. The method of claim 14, wherein the boundary is a shape selected from the group consisting of a planar shape, a cylindrical shape, an aspheric cylindrical shape, a conical shape, and a deformed conical shape.   The method is for forming a blend by moving solid particles through the first solution and the second solution prior to curing the first solution and the second solution. The method of claim 14, further comprising mixing the first solution and the second solution. The first solution and the second solution have different densities;
The step of providing the mold is a step of providing a mold having the first region and the second region that form a cavity for containing the first solution and the second solution,
The method has a larger one of the first solution and the second solution under the region of the cavity having one of the first solution and the second solution having a smaller refractive index. 15. The method of claim 14, further comprising positioning a mold having the region of the cavity having the other having a refractive index.   The method is for forming a blend by moving particles through the first solution and the second solution prior to curing the first solution and the second solution. The method of claim 17, further comprising mixing the first solution and the second solution. A method of making a lens that includes a first portion having a first refractive index and a second portion having a second refractive index, comprising:
Providing a mold having a first region and a second region;
Filling the first region of the mold with a first solution and filling the second region of the mold with a second solution; the first solution and the second solution comprising: When the second solution and the second solution are cured, they can be cured to form solids having different refractive indices;
Moving the solid particles through the intermediate region to form a blend between the first region and the second region, the first solution and the second solution in the intermediate region; Mixing the steps,
And then smoothing between the first portion having the first refractive index, the second portion having the second refractive index, and the first refractive index and the second refractive index. Curing the first solution and the second solution to form the solid having a refractive index that changes to and having an intermediate portion between the first portion and the second portion. The method comprising the steps of: The method includes locating a second region of the mold having a second solution under the first region of the mold having the first solution;
The method further comprises introducing the particles into the first region and moving the particles from the first region through the intermediate region by means selected from the group consisting of gravity and centrifugal force. The method of claim. A method of making a lens that includes a first portion having a first refractive index and a second portion having a second refractive index, comprising:
Providing a mold surface;
To form a solid having the first refractive index on at least a portion of the mold surface by moving a first sprayer along a predetermined first path to form a first deposit. Spraying a first curable solution from the first nebulizer;
To form a solid having the second refractive index on at least a portion of the mold surface by moving a second sprayer along a predetermined second path to form a second deposit. Spraying a second curable solution from the second nebulizer;
Creating a common deposition region of the sprayed first solution and the second solution to form a blend region having both the first solution and the second solution;
Controlling at least the length in the direction of the first predetermined path and the second predetermined path and the width of the common deposition region having a width in a direction orthogonal to the direction;
Smooth change between the first portion having the first refractive index, the second portion having the second refractive index, and the first refractive index and the second refractive index. Curing at least partially the first solution and the second solution to form an intermediate portion between the first portion and the second portion. The method comprising the steps of: (A) spraying each of the first solution for deposition on the first portion and the second solution for deposition on the second portion, and (b) before the first Spraying each of the first solution to deposit on the second portion and the second solution to deposit on the first portion;
After at least partially curing the sprayed first deposit and second deposit of the first solution and the second solution, respectively, in a method selected from the group consisting of:
The step of spraying the first solution and the second solution, respectively, includes the step of repeating the step of spraying the first solution and the second solution, respectively. Said method Providing the mold surface includes providing a flexible mold surface;
The method according to claim 22, further comprising a step of changing the shape of the mold surface before the step of repeating the step of spraying the first solution and the second solution, respectively.   The step of controlling the width of the common deposition region of the first solution and the second solution includes changing a spray direction of the sprayer and changing a distance of the sprayer from the mold surface. A step of changing the shape of the sprayed first deposit and the second deposit, and a spray barrier at a selected distance on the common deposition region between the sprayers. And a predetermined amount of the sprayed first solution and second solution is selected from the group consisting of passing under the barrier and depositing over the barrier. 22. The method of claim 21, comprising the step of:   The mold surface includes a cylindrical non-optically functioning step, a conical non-optically functioning step, and a non-optically functioning step combining a cylindrical shape and a conical shape. 23. The method of claim 21, comprising a fullnel lens having a selected optically non-functional step.

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