Progressive lens soft film and method for manufacturing the same

Abstract

To provide a device including a progressive lens and a method which are configured to perform a distance vision correction and a close vision correction.SOLUTION: The progressive lens includes: a single-focus distance vision correction lens (22) configured to perform a part of a distance vision correction and a film (24) connected to the single-focus distance vision correction lens (22). The film (24) defines: a distance vision correction unit (26) configured to perform the other part of the distance vision correction; a close vision correction unit (28) configured to perform an additional close distance vision correction; and an intermediate unit (30) in which the film moves between the distance vision correction unit and the close vision correction unit. Other applications are also described.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to and is a continuation-in-part of U.S. Provisional Patent Application No. 62 / 906,157, by Katzman, entitled "Apparatus and method for manufacturing a progressive lens," filed on September 26, 2019, and also claims priority to and is a continuation-in-part of U.S. Provisional Patent Application No. 16 / 718,448, by Katzman, entitled "A progressive lens and method of manufacture thereof," filed on December 18, 2019.

[0002] Some applications of the present invention relate generally to ophthalmic lenses, and more specifically to making progressive lenses using a single vision hard lens and a film bonded to the lens. [Background technology]

[0003] Presbyopia is a condition that gradually affects a large portion of the population over the age of 40. The condition results in a progressive deterioration of the ability to focus clearly on nearby objects. Presbyopia is usually treated with multifocal glasses, progressive glasses, or contact lenses, as laser assisted myopia surgery (i.e. LASIK) and other types of surgery are not suitable to treat the condition.

[0004] Spectacles use corrective lenses to correct presbyopia and other accommodation disorders. Many people who suffer from presbyopia also suffer from myopia (i.e. nearsightedness). The basic solution for such people is the use of multifocal spectacle lenses. Multifocal spectacle lenses have two or more lens powers, each suitable for objects at different distances. Bifocal lenses have two lens powers, and trifocal lenses have three lens powers. Progressive spectacle lenses are characterized by a gradient of increasing lens power. The gradient starts at the wearer's distance prescription and reaches a maximum add, or full reading addition, at the bottom of the lens. The add in the center of the lens usually allows clear vision at intermediate distances, such as reading text on a computer screen. The length of the progressive power gradient on the lens surface depends on the lens design, and the final add is typically between 0.50 and 3.50 diopters. The value of the prescribed add depends on the degree of presbyopia of the patient.

[0005] Multifocal and progressive lenses are generally relatively expensive. A major factor in the high cost of multifocal and progressive lenses is the fact that there are a huge number (millions) of possible prescription combinations when considering near vision correction, distance vision correction, astigmatism, and the angle of astigmatism. The large number of possible combinations means that most prescriptions cannot be kept in stock, but rather must be manufactured on a custom-made basis based on the patient's needs. Summary of the Invention

[0006] According to some applications of the present invention, a progressive lens configured to provide distance and near vision correction includes a single vision distance correcting lens and a film coupled to the single vision distance correcting lens. Typically, the single vision distance correcting lens is configured to provide only a portion of the distance vision correction, and the film is configured to provide the remainder of the distance vision correction. The film also provides additional near vision correction within the near vision correction portion of the film, and the film is configured to define an intermediate portion that transitions between the near vision correction portion and the distance vision correction portion, and the film provides a portion of the distance vision correcting refractive power. Typically, the transition between the distance vision correction portion and the near vision correction portion of the film is a smooth transition with substantially no noticeable boundary between the regions having different refractive powers.

[0007] Single vision lenses are typically rigid stock lenses. As explained above, the progressive function of a "lens-film combination" (i.e., a lens and film combination) is typically provided by the film. By separating the corrective functions in this manner, a large number of prescriptions can typically be provided using a relatively small inventory of lenses and films, as described, for example, in U.S. Patent No. 9,995,948 to Arieli, which is incorporated herein by reference. The film is typically flexible (at least under given conditions), so that it can accommodate a variety of different rigid lens shapes and / or sizes while still maintaining its optical properties. Typically, this further reduces the inventory of lenses and films that need to be maintained compared to when the film could only be combined with lenses having certain shapes and / or sizes. In some applications, the film is only flexible under given conditions (e.g., when the film is heated to a temperature above a given temperature), but under typical ambient conditions (e.g., at temperatures below 50 degrees Celsius), the film is substantially rigid, so that the film has the characteristics of a rigid lens. Typically, the given conditions are applied to the film during the manufacture of the lens-film combination, specifically when the film is bonded to the single vision distance correcting lens. Thus, the flexibility of the film allows the film to conform to the shape of the single vision distance correcting lens. For example, the film may be heated to a temperature above a given temperature during the manufacture of the lens-film combination, specifically when the film is bonded to the single vision distance correcting lens. Typically, the film is configured to maintain its optical properties even when placed under the given conditions (e.g., when heated to a temperature above the given temperature). Thereafter, when the lens-film combination is placed under ambient conditions (e.g., a temperature below 50 degrees Celsius), the film assumes a rigid state.

[0008] Typically, if a user requires X diopters of distance vision correction, a single vision lens would be selected for the lens-film combination to provide Y diopters of correction rather than providing full correction. The film would typically be configured to provide the remainder of the distance vision correction (i.e., the difference between X and Y). In the near vision portion of the film (near the bottom of the film), the film provides the additional power needed for near vision, and along the middle portion, the film provides progressive power by transitioning (typically smoothly as described above) between the distance vision correction and the near vision correction. This is in contrast to other types of lens-film combinations where a lens is used to provide full distance vision correction of X diopters. In such cases, the film would be designed as a plano lens in the distance vision portion.

[0009] Typically, using a film to provide part of the distance vision correction has many advantages over a monofocal lens alone providing the entire distance vision correction. If a film is used to provide the near vision and progressive functions of the combination without providing any distance vision correction, the film will have the structure of a typical positive prescription lens (even after the industry standard prism thinning procedure by removing the prisms from the film). Such lenses are thinner at the edges and thicker in the center, and the larger the diameter of the lens (i.e., the film in this case), the thicker the center of the lens. In contrast, if a film is used to provide part of the distance vision correction (in accordance with some applications of the present invention), the film is typically designed to have a more uniform thickness, as described in more detail below. Even more typically, the entire lens-film combination is designed to have a thinner overall thickness than if the entire distance vision correction were to be provided by a monofocal lens. Even more typically, the entire lens-film combination is designed to have a relatively uniform thickness over the area of ​​the lens-film combination, so that the thickness of the combination does not increase substantially at the edges or center as the diameter of the lens-film combination increases.

[0010] All of the lens-film combination features described above are typically desirable for cosmetic purposes, and such features are typically desirable for providing functional brow spacing and for providing compatibility of the lens-film combination with as wide a variety of frame styles, shapes and sizes as possible.

[0011] Also, a film with a more uniform thickness typically allows the film to be manufactured using molten thermoplastic material and injection molding techniques that would otherwise be difficult to implement. This is because if one wants the film to have the structure of a typical positive prescription lens (i.e. thinner edges and thicker center), the mold cavity will have narrow edges and a wider center. The flow profile of the thermoplastic material flowing through such a cavity can typically create stress marks that remain after the material cools and are therefore unacceptable for ophthalmic use. Also, to obtain a reasonable thickness in the center of the film, the entrance to the cavity must be very narrow, and it is typically difficult to inject molten thermoplastic material through a narrow entrance. In contrast, the mold cavity used to manufacture the present film (with a substantially uniform thickness) is defined by substantially parallel cavity walls. Typically, the thermoplastic material will flow smoothly through such a cavity, resulting in a film without stress marks. In some applications, a film with a more uniform thickness facilitates easier manufacturing of the film when using other manufacturing methods, such as casting and / or stamping methods (e.g., using thermoplastic and / or thermosetting materials).

[0012] In this application, the term "film" should be interpreted to mean a relatively thin material that is at least partially flexible under at least given conditions. As noted above, in some applications the film is flexible only under given conditions (typically applied to the film during manufacture of the lens-film combination), while under typical ambient conditions the film is substantially rigid, such that the film has the characteristics of a rigid lens.

[0013] Thus, according to some applications of the present invention: 1. An apparatus including a progressive lens configured to provide distance and near vision correction, the progressive lens comprising: a monofocal distance vision correcting lens configured to provide only a portion of the distance vision correction; a film coupled to the single vision distance correcting lens, the film being a distance vision correction portion configured to provide the remainder of the distance vision correction; a near vision correction portion configured to provide additional near vision correction; An apparatus is provided in which the film is configured to define an intermediate section that transitions between the distance vision correction section and the near vision correction section.

[0014] In some applications, the single vision distance corrective lens is rigid. In some applications, the film comprises a flexible film. In some applications, the film is configured to be flexible under certain conditions and is configured to be rigid, e.g., have the characteristics of a rigid lens, under typical ambient conditions. In some applications, the film is configured to be flexible above a certain temperature and is configured to be rigid, e.g., have the characteristics of a rigid lens, at temperatures below 50 degrees Celsius.

[0015] For some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the thickness of the film is substantially uniform. For some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the ratio of the center thickness of the film to the edge thickness of the film is 1:2 to 2:1 when the diameter of the film is 70 mm or greater. For some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the ratio of the center thickness of the film to the edge thickness of the film is 1:1.6 to 1.6:1 when the diameter of the film is 40 mm or greater.

[0016] For some applications, the distance vision correction portion of the film is configured to provide distance vision correction that is an integer multiple of 0.25 diopters of the distance vision correction provided by the single vision distance vision correcting lens.

[0017] In some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.1 mm. In some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm. In some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even when the center thickness of the film is 0.7 mm or less. In some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even when the diameter of the film is 70 mm or more. In some applications, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even when the center thickness of the film is 0.7 mm or less and the diameter of the film is 70 mm or more.

[0018] In some applications, the film comprises a thermoplastic material, and an edge thickness of the film greater than 0.1 mm facilitates the production of the film using injection molding of the thermoplastic material when the thermoplastic material is in a molten form. In some applications, an edge thickness of the film greater than 0.1 mm facilitates the production of the film using injection molding of the thermoplastic material when the thermoplastic material is in a molten form without generating stress marks in the material.

[0019] According to some applications of the present invention, A progressive lens configured to provide distance vision correction and near vision correction, Film a far vision correction portion configured to perform a portion of the far vision correction; a near vision correction portion configured to provide additional near vision correction; Configuring the film to define an intermediate section that transitions between the distance vision correction and the near vision correction; and There is further provided a method that includes manufacturing by bonding the film to a single vision distance correcting lens configured to provide the remainder of the distance vision correction.

[0020] The present invention will be more fully understood from the following detailed description of the embodiments thereof and the accompanying drawings, in which: [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a progressive lens made from a lens-film combination, according to some applications of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of a cross section of a lens-film combination according to some applications of the present invention, in which the single vision lens provides all of the distance vision correction power and the film only transitions between the distance vision correction and the full near vision add correction without affecting the distance vision correction. [Diagram 3] FIG. 1 is a schematic diagram of a cross section of a lens-film combination according to some applications of the present invention, in which the single vision lens provides all of the distance vision correction power and the film only transitions between the distance vision correction and the full near vision add correction without affecting the distance vision correction. [Figure 4] 2 is a schematic diagram of a cross section of a lens-film combination according to some applications of the present invention, in which a single vision lens and a film each provide a portion of the distance vision corrective power. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Reference is now made to FIG. 1, which is a schematic diagram of a progressive lens 20 made from a lens-film combination according to some applications of the present invention. The progressive lens 20 is configured to provide distance and near vision correction for a user suffering from both myopia and presbyopia. Typically, the progressive lens is incorporated into a pair of glasses (as shown). The progressive lens 20 comprises a lens-film combination including a single vision distance correcting lens 22 and a film 24 bonded to the single vision distance correcting lens. Typically, the film 24 is bonded to an inner surface of the single vision lens 22 (i.e., the surface of the lens closer to the user's eye when the lens is incorporated into a pair of glasses worn by a user). Alternatively, the film 24 is bonded to an outer surface of the single vision lens 22 (i.e., the surface of the lens farther from the user's eye when the lens is incorporated into a pair of glasses worn by a user). Typically, the film is bonded to the prime lens via an adhesive layer and / or using alternative techniques such as those described in U.S. Pat. No. 9,995,948 to Arieli, which is incorporated herein by reference.

[0023] Typically, the single vision lens 22 is configured to provide only a portion of the distance vision correction, and the film 24 is configured to provide the remainder of the distance vision correction. The film is further configured to provide near vision add correction in the near vision correction portion 28 of the film, and to define an intermediate portion 30 where the film transitions (typically smoothly, as described above) between the near vision correction portion and the distance vision correction portion 26 where the film provides only a portion of the distance vision corrective power.

[0024] The single vision lens 22 is typically an off-the-shelf lens. As described above, the progressive function of the lens-film combination is typically provided by the film. By separating the corrective functions in this manner, a large number of prescriptions can typically be provided using a relatively small inventory of lenses and films, as described, for example, in U.S. Patent No. 9,995,948 by Arieli, which is incorporated herein by reference. The film is typically flexible (at least under given conditions), so that it can accommodate a variety of different hard lens shapes, sizes, and / or angles (including spherical and toric lenses) while still maintaining its optical properties. Typically, this further reduces the inventory of lenses and films that need to be maintained compared to when the film could only be combined with lenses having certain shapes and / or sizes. In some applications, the film is only flexible under given conditions (e.g., when the film is heated to a temperature above a given temperature), but under typical ambient conditions (e.g., at temperatures below 50 degrees Celsius), the film is substantially rigid, so that the film has the characteristics of a rigid lens. Typically, the given conditions are applied to the film during the manufacture of the lens-film combination, specifically when the film is bonded to the single vision distance correcting lens. Thus, the flexibility of the film allows the film to conform to the shape of the single vision distance correcting lens. For example, the film may be heated to a temperature above a given temperature during the manufacture of the lens-film combination, specifically when the film is bonded to the single vision distance correcting lens. Typically, the film is configured to maintain its optical properties even when placed under the given conditions (e.g., when heated to a temperature above the given temperature). Thereafter, when the lens-film combination is placed under ambient conditions (e.g., a temperature below 50 degrees Celsius), the film assumes a rigid state.

[0025] In the following sections of this application, an example of a lens-film combination in which all of the distance vision corrective power is provided by a single vision lens is described with reference to Figures 2 and 3. Then, an example of a lens-film combination in which a portion of the distance vision corrective power is provided by a film is described with reference to Figure 4. Some advantages of having a film that provides a portion of the distance vision corrective power are illustrated by comparing the example shown in Figure 4 with the example shown in Figures 2 and 3. However, while these advantages are illustrated, the scope of this application includes lens-film combinations in which all of the distance vision corrective power is provided by a single vision lens, according to the general principles described with reference to Figures 2 and 3. Examples of lens-film combinations where all of the distance vision correction is provided by the lens Reference is now made to Figures 2 and 3, which are schematic illustrations of cross-sections of lens-film combinations (i.e., a combination of a single vision distance correcting lens 22 and a film 24) in which the lens provides all of the distance vision corrective power, according to some applications of the present invention. For example, if the desired distance vision power is -1.50 diopters, then the lens 22 would provide all of the -1.50 diopters, and the film would be a plano lens with additional near vision correction in the near vision correcting portion of the film, and an intermediate portion where the film transitions between the near vision correcting portion and the distance vision non-correcting portion. In other words, the film would have no power in the distance vision correcting portion 26 of the film.

[0026] The cross sections shown in Figures 2 and 3 are taken along the vertical centerline of the lens-film combination shown in Figure 1 (i.e. along the y-axis, i.e. along the line where x=0 in Figure 1). In the embodiment shown in Figures 2 and 3, the inner (concave) surface 40 of film 24 is shaped to provide the optical correction function of the film, while the outer (convex) surface 42 of film 24 is spherical (or possibly aspheric) and matches the existing concave inner surface of the single vision lens. The distance vision correction prescription power of film 24 is given by the difference in curvature between surface 40 and surface 42 at each measurement point, which in this case is zero (the film is a plano film with no additional refractive power in the distance vision region). Surface 43 is the inner (concave) surface of lens 22. Because film 24 is typically flexible and film surface 42 is bonded to surface 43, the convex curvature of surface 42 typically matches the concave curvature of surface 43. Surface 44 is the outer (convex) surface of lens 22. The distance vision prescription power of lens 22 is given by the difference in curvature between surfaces 43 and 44 at each measurement point.

[0027] As shown in Figures 2 and 3, film 24 has the structure of a positive corrective lens, thinner at the edges and thicker in the center.

[0028] 2 shows an example where the thickness (i.e., center thickness) of the film 24 is 1.1 mm and the refractive index of each of the prime lens and film is 1.53. Examples of parameters for such a lens-film combination are shown in Tables 1-5 presented in the appendix hereto. Note that some of the dimensions presented in Tables 1-5 are negative and thus physically impossible. However, this example is presented to convey the point that it is practically impossible to build a lens-film combination with certain constraints.

[0029] Table 1 (presented in the Appendix) shows the parameters of the outer (convex) surface 42 of the film 24, and the center thickness of the film.

[0030] Table 2 (shown in the Appendix) gives the edge thickness of film 24 assuming a film diameter of 60 mm. The table shows that if a center thickness of 1.1 mm is applied, the edge thickness at ±30 mm would be approximately 0.3 mm, which is very difficult to achieve in real world manufacturing.

[0031] Table 3 (presented in the Appendix) gives the edge thicknesses of film 24 assuming a film diameter of 70 mm. Table 3 shows that for a film with a diameter of 70 mm and a center thickness of 1.1 mm, one edge will have an edge thickness of less than 0.3 mm and the other edge will have a negative edge thickness, making it impossible to produce a film with these characteristics.

[0032] Table 4 (shown in the Appendix) shows the convex radius of surface 44 of lens 22 with a prescription of -1.75 diopters and the center thickness of the lens. Note that if a single vision lens has a base 4.00 diopter concave curvature, then to provide the -1.75 diopter prescription, the lens must have a convex curvature of 2.25 diopters. Using the thin lens formula for a lens with a refractive index of 1.53, the radius may be approximated by dividing 530 mm by the convex curvature. Thus, the radius on the convex side is 530 / 2.25=235.56 mm.

[0033] Table 5 (presented in the Annex) gives the center and edge thicknesses of lens-film combinations for (a) a lens-film diameter of 60 mm and (b) a lens-film diameter of 70 mm. It may be observed that the edge thickness increases with increasing diameter. Note that Table 5 is theoretical since in some cases the total thickness consists of a positive thickness (of the prime lens) and a negative thickness (of the film), which is physically impossible.

[0034] Figure 3 shows an example where the center thickness of the film 24 is set to 0.7 mm, and the refractive index of the lens and film are each 1.53. Examples of parameters for such a lens-film combination are shown in Tables 6-10 presented in the appendix hereto. Note again that some of the dimensions are negative and physically impossible. However, this example is presented to convey the point that it is practically impossible to build a lens-film combination with certain constraints.

[0035] Table 6 (presented in the Appendix) shows the parameters of the outer (convex) surface 42 of the film 24, and the center thickness of the film.

[0036] Table 7 (presented in the Appendix) gives the edge thicknesses of film 24 assuming a film diameter of 60 mm. The table shows that when applying a center thickness of 0.7 mm (presented in Table 6), the edge thicknesses at ±30 mm are also negative, which indicates that it is not possible to manufacture a film with such characteristics.

[0037] Table 8 (presented in the Appendix) gives the edge thickness of film 24 assuming a film diameter of 70 mm. Table 8 shows that for a film diameter of 70 mm and a center thickness of 0.7 mm, the edge thickness is again negative, making it impossible to produce a film with such characteristics.

[0038] Table 9 (shown in the Appendix) shows the convex radius of surface 44 of a single vision lens 22 with a prescribed power of -1.75 diopters and the center thickness of the lens 22. As stated above, if the lens has a base 4.00 diopter concave curvature, then to provide the prescribed power of -1.75 diopters, the lens must have a convex curvature of 2.25 diopters. Using the thin lens formula for a lens with a refractive index of 1.53, the radius may be approximated by dividing 530 mm by the convex curvature. Thus, the radius on the convex side is 530 / 2.25=235.56 mm.

[0039] Table 10 (presented in the Appendix) gives the center and edge thicknesses of lens-film combinations for (a) a lens-film diameter of 60 mm and (b) a lens-film diameter of 70 mm. Again, it may be observed that the edge thickness increases with increasing diameter. Note that Table 10 is theoretical since in some cases the total thickness consists of a positive thickness (of the prime lens) and a negative thickness (of the film), which is physically impossible.

[0040] As the data presented in Tables 1-10 demonstrate, when a film 24 is designed such that its distance vision correction portion 26 is a plano lens, it generally turns out to be the case that (a) certain desired combinations of center thickness and lens diameter are physically impossible or substantially impractical, (b) certain lens-film combinations require large center thicknesses (to avoid impractically small or negative edge thicknesses), especially for lenses having larger diameters, and / or (c) the film has a substantially non-uniform thickness having the structure of a typical positive prescription lens. Examples of lens-film combinations where part of the distance vision correction power is provided by the film 4, according to some applications of the present invention, film 24 is designed such that it provides optical correction for distance vision. To compensate for this, the optical power of the distance vision correction provided by monofocal lens 22 is different (e.g., less) than the overall distance vision correction required for the desired overall prescription power. For example, if the desired distance vision power of the lens-film combination is -1.50 diopters, monofocal lens 22 may provide a distance vision power of the lens-film combination of -0.50 diopters, and film 24 may provide the remaining distance vision power of -1.00 diopters.

[0041] Typically, the amount of distance vision power assigned to film 24 is determined to result in a film having a substantially uniform thickness. For example, if the add correction in the near vision portion is +2.00 diopters, then to balance the thickness of film 24, the film may be configured to provide a -1.00 diopter of power in the distance vision portion as in the example above.

[0042] In some cases, additional considerations may cause the power assigned to the distance vision portion of the film to be non-uniform in thickness. For example, another consideration is that it is undesirable for a film to have an unusual power in the distance vision portion (e.g., a power that is not an integer multiple of 0.25 diopters) because it means that the film cannot be paired with an off-the-shelf lens that provides a common overall distance vision correction. For example, to provide a given additional power in the near vision portion of the film, the thickness of the film may be uniform if the power of the distance vision portion is set to -1.34 diopters. However, in such a case, the power of the distance vision portion will typically be set to -1.25 diopters or -1.5 diopters depending on the above considerations.

[0043] Reference is again made to Figure 4, which is a schematic diagram of a cross-section of a lens-film combination in which the single vision lens 22 and the film 24 each provide a portion of the distance vision corrective power, according to some applications of the present invention. The cross-section shown in Figure 4 is taken along the vertical centerline of the lens-film combination shown in Figure 1 (i.e., along the line where x=0 in Figure 1). Figure 4 shows an example in which the center thickness (i.e., center thickness) of the film 24 is 0.7 mm, and the refractive index of each of the lens and film is 1.53. Example parameters of such a lens-film combination are shown in Tables 11-15, presented in the appendix hereto.

[0044] Table 11 (presented in the Appendix) shows the parameters of the outer (convex) surface 42 of the film 24, and the center thickness of the film.

[0045] Table 12 (shown in the Appendix) shows the edge thickness for Film 24 assuming a film diameter of 60 mm. Table 13 shows the edge thickness for Film 24 assuming a film diameter of 70 mm. As can be seen, the edge thickness for both scenarios is reasonable and well above the 0.3 mm threshold that makes the film viable from a manufacturing standpoint.

[0046] Table 14 (shown in the Appendix) shows the convex radius of surface 44 of a fixed vision lens 22 with a prescribed power of -1.00 diopters and the center thickness of the lens. If the fixed vision lens has a base 4.00 diopters concave curvature, then to provide the prescribed power of -1.00 diopters, the lens must have a convex curvature of 3.00 diopters. Using the thin lens formula for a lens with a refractive index of 1.53, the radius may be approximated by dividing 530 mm by the convex curvature. Thus, the radius on the convex side is 530 / 3=176.67 mm.

[0047] Table 15 (shown in the Appendix) shows the center and edge thicknesses of lens-film combinations for two cases: (a) a lens-film diameter of 60 mm, and (b) a lens-film diameter of 70 mm. As shown in both Tables 11-15 and FIG. 4, designing film 24 as described above results in a film 24 and lens-film combination having a more uniform thickness, allowing for the manufacture of a lens-film combination with a diameter of 70 mm. Advantages of having some of the distance vision correction provided by film 2-4 and the accompanying description, using a film 24 to provide part of the distance vision correction (as shown in FIG. 4) offers many advantages over a single vision lens providing all of the distance vision correction (as shown in FIGS. 2 and 3). If a film is used to provide the near vision and progressive functions of the combination without providing any distance vision correction, the film will have the structure of a typical positive prescription lens (even after the industry standard prism thinning procedure of removing prisms from the film). Such lenses are typically thinner at the edges and thicker in the center, with the lens (i.e., the film in this case) becoming thicker in the center as the diameter of the lens (in accordance with some applications of the present invention) increases. In contrast, if a film is used to provide part of the distance vision correction (as described in more detail below), the film is typically designed to have a more uniform thickness. More typically, the entire lens-film combination is designed to have a thinner overall thickness than would be the case if all of the distance vision correction were to be provided by the lens. Even more typically, the entire lens-film combination is designed to have a relatively uniform thickness over the area of ​​the lens-film combination, so that as the diameter of the lens-film combination increases, the thickness of the combination does not increase substantially at the edges or center. All of the lens-film combination features described above are typically desirable for cosmetic purposes. Such features are also typically desirable to provide functional brow spacing and to provide compatibility of the lens-film combination with as wide a variety of frame styles, shapes and sizes as possible.

[0048] It should be noted that the issue of total thickness and thickness uniformity of progressive lenses is particularly important in progressive lenses, including the lens-film combination described herein. A film with a more uniform thickness typically allows the film to be manufactured using molten thermoplastic material and injection molding techniques that would otherwise be difficult to implement. This is because if one wanted the film to have the structure of a typical positive prescription lens (i.e. thinner edges and thicker center), the mold cavity would have narrow edges and a wider center. The flow profile of the thermoplastic material flowing through such a cavity could create stress marks that would remain after the material cools and would be unacceptable for ophthalmic use. Also, to obtain a reasonable thickness in the center of the film, the entrance to the cavity would need to be very narrow, and it is typically difficult to inject molten thermoplastic material through a narrow entrance. In contrast, the mold cavity used to manufacture the film of the present application (with substantially uniform thickness) is defined by substantially parallel cavity walls. Typically, the thermoplastic material would flow smoothly through such a cavity, resulting in a film without stress marks. In some applications, a film having a more uniform thickness facilitates easier manufacturing of the film when using other manufacturing methods, such as casting and / or stamping methods (e.g., using thermoplastic and / or thermoset materials).

[0049] Thus, according to some applications of the present invention, the distance vision correction portion of the film is configured to provide a portion of the distance vision correction of the entire lens-film combination, resulting in a substantially uniform film thickness. In some applications, the ratio of center film thickness to edge film thickness is 1:2 to 2:1 when the film diameter is 70 mm or greater. In some applications, the ratio of center film thickness to edge film thickness is 1:1.6 to 1.6:1 when the film diameter is 40 mm or greater.

[0050] In some applications, the edge thickness of the film is at least 0.1 mm (e.g., at least 0.3 mm). In some applications, the edge thickness of the film is at least 0.3 mm, even if the center thickness of the film is 0.7 mm or less and / or the diameter of the film is 70 mm or more. In some applications, the film comprises a thermoplastic material, and the edge thickness of the film is greater than 0.1 mm (e.g., greater than 0.3 mm) facilitates the production of the film using injection molding of the thermoplastic material when the thermoplastic material is in a molten form. For example, the edge thickness of the film is greater than 0.1 mm (e.g., greater than 0.3 mm) may facilitate the production of the film using such injection molding without stress marks in the material.

[0051] It should be noted that, as noted above, modifying the optical design of the film to provide optical power in the distance vision portion can introduce horizontal prism that can cause a generally undesirable strabismus effect, and thus lens 22 and / or film 24 are typically configured to provide compensating horizontal prism.

[0052] Some advantages of having a film that provides a portion of the distance vision corrective power of a lens-film combination have been described above by comparing the example shown in Figure 4 with the examples shown in Figures 2 and 3. While these advantages are noted, the scope of this application includes lens-film combinations in which all of the distance vision corrective power is provided by the single vision lens alone, or by the film alone. As noted above, some of the examples described with reference to Figures 2 and 3 are physically impossible. However, the scope of this application includes lens-film combinations in which all of the distance vision corrective power is provided by the single vision lens, following the general principles described with reference to Figures 2 and 3.

[0053] It will be understood by those skilled in the art that the present invention is not limited to what has been particularly shown and described above, but rather the scope of the present invention includes both combinations and subcombinations of the various features described in the foregoing specification, as well as variations and modifications thereof that are not in the prior art and that would occur to those skilled in the art upon reading the foregoing description. Appendix - Tables 1 to 15 Tables 1 to 5 relate to the example shown in FIG.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3]

[0057] [Table 4]

[0058] [Table 5] Tables 6 to 10 relate to the example shown in FIG.

[0059] [Table 6]

[0060] [Table 7]

[0061] [Table 8]

[0062] [Table 9]

[0063] [Table 10] Tables 11 to 15 relate to the example shown in FIG.

[0064] [Table 11]

[0065] [Table 12]

[0066] [Table 13]

[0067] [Table 14]

[0068] [Table 15]

Claims

1. 1. An apparatus including a progressive lens configured to provide distance and near vision correction, the progressive lens comprising: a monofocal distance vision correcting lens configured to provide only a portion of the distance vision correction; a film coupled to the single vision distance correcting lens; The film a distance vision correction portion configured to provide the remainder of the distance vision correction; a near vision correction portion configured to provide additional near vision correction; the film is configured to define an intermediate section that transitions between the distance vision correction section and the near vision correction section.

2. The device of claim 1 , wherein the single vision distance correcting lens is rigid.

3. The device of claim 1 , wherein the film comprises a flexible film.

4. The device of claim 1 , wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the thickness of the film is substantially uniform.

5. 2. The device of claim 1, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the ratio of center thickness of the film to edge thickness of the film is 1:2 to 2:1 when the diameter of the film is 70 mm or greater.

6. 2. The device of claim 1, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the ratio of center thickness of the film to edge thickness of the film is 1:1.6 to 1.6:1 when the diameter of the film is 40 mm or greater.

7. 2. The device of claim 1, wherein the distance vision correction portion of the film is configured to provide distance vision correction that is an integer multiple of 0.25 diopters of the distance vision correction provided by the single vision distance vision correcting lens.

8. The device of claim 1 , wherein the film is configured to be flexible under given conditions and configured to be rigid, such as having the characteristics of a rigid lens, under typical ambient conditions.

9. The device of claim 1 , wherein the film is configured to be flexible above a given temperature and configured to be rigid, such as having the characteristics of a rigid lens, at temperatures below 50 degrees Celsius.

10. 10. The device of claim 1, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.1 mm.

11. 11. The device of claim 10, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm.

12. 12. The device of claim 11, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even if the center thickness of the film is 0.7 mm or less.

13. 12. The device of claim 11, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even when the diameter of the film is 70 mm or greater.

14. 12. The device of claim 11, wherein the distance vision correction portion of the film is configured to provide a portion of the distance vision correction such that the edge thickness of the film is at least 0.3 mm even when the center thickness of the film is 0.7 mm or less and the diameter of the film is 70 mm or more.

15. 11. The apparatus of claim 10, wherein the film comprises a thermoplastic material and the edge thickness of the film is greater than 0.1 mm to facilitate manufacturing of the film using injection molding of the thermoplastic material when in a molten form.

16. 16. The apparatus of claim 15, wherein the edge thickness of the film is greater than 0.1 mm, facilitating production of the film using injection molding of the thermoplastic material when in a molten form without introducing stress marks into the material.

17. 1. A method comprising manufacturing a progressive lens configured to provide distance vision correction and near vision correction, said manufacturing the progressive lens comprising: The film, A far vision correction unit configured to perform a portion of the far vision correction; a near vision correction portion configured to provide additional near vision correction; an intermediate section where the film transitions between the distance vision correction section and the near vision correction section; and configuring the producing said progressive lens by bonding said film to a single vision distance correcting lens configured to provide the remainder of said distance vision correction.

18. 20. The method of claim 17, wherein the single vision distance correcting lens comprises a rigid single vision distance correcting lens, and bonding the film to the single vision distance correcting lens comprises bonding the film to the rigid single vision distance correcting lens.

19. 20. The method of claim 17, wherein the film comprises a flexible film, and bonding the film to the single vision distance correcting lens comprises bonding the flexible film to the single vision distance correcting lens.

20. 20. The method of claim 17, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film to have a thickness that is substantially uniform.

21. 20. The method of claim 17, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that when the diameter of the film is 70 mm or greater, the ratio of the center thickness of the film to the edge thickness of the film is 1:2 to 2:

1.

22. 20. The method of claim 17, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the ratio of the center thickness of the film to the edge thickness of the film is 1:1.6 to 1.6:1, even when the diameter of the film is 40 mm or greater.

23. 20. The method of claim 17, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the distance vision correction provided by the single vision distance vision correcting lens is an integer multiple of 0.25 diopters.

24. 18. The method of claim 17, wherein the film is configured to be flexible under given conditions and is configured to be rigid, such as having the characteristics of a rigid lens, under typical ambient conditions, and bonding the film to the single vision distance corrective lens comprises bonding the film to the single vision distance corrective lens while the given conditions are applied to the film, thereby causing the film to be flexible.

25. 18. The method of claim 17, wherein the film is configured to be flexible above a given temperature and is configured to be rigid, such as having the characteristics of a rigid lens, at temperatures below 50 degrees Celsius, and bonding the film to the single vision distance corrective lens comprises bonding the film to the single vision distance corrective lens while the film is heated to a temperature above the given temperature, thereby causing the film to be flexible.

26. 26. The method of any one of claims 17 to 25, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion comprises configuring the film such that the edge thickness of the film is at least 0.1 mm.

27. 27. The method of claim 26, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the edge thickness of the film is at least 0.3 mm.

28. 28. The method of claim 27, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the edge thickness of the film is at least 0.3 mm even when the center thickness of the film is 0.7 mm or less.

29. 28. The method of claim 27, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the edge thickness of the film is at least 0.3 mm even when the diameter of the film is 70 mm or greater.

30. 28. The method of claim 27, wherein configuring the film to define the distance vision correction portion, the near vision correction portion, and the intermediate portion includes configuring the film such that the center thickness of the film is 0.7 mm or less and the edge thickness of the film is at least 0.3 mm even when the diameter of the film is 70 mm or more.

31. 27. The method of claim 26, wherein the film comprises a thermoplastic material, the method comprising producing the film using injection molding of the thermoplastic material when the thermoplastic material is in a molten form, and configuring the film to have an edge thickness of at least 0.1 mm comprises facilitating the injection molding.

32. 32. The method of claim 31 , wherein configuring the film to have an edge thickness of at least 0.1 mm comprises facilitating injection molding of the thermoplastic material when in a molten form without generating stress marks in the material.

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