MXPA96001676A - Design of concentral anular ring lens with minimum angles between anular ring segments adyacen - Google Patents

Abstract

Multifocal concentric annular ring lens designs are described between adjacent annular ring segments, the present invention particularly pertains to spherical lens designs having different radii of curvature, which allows a numerically controlled (NC) machine to be programmed to machine the adjacent annular segments and the transitions between them, a nitrifocal concentric annular ring lens has either a front or rear surface defining a plurality of spherical annular rings having different spherical optical powers with different spherical radii; teachings of the present invention, the radius of curvature of a first spherical annular ring is displaced along the longitudinal axis of the lens relative to the radius of curvature of a second spherical annular ring adjacent, the radii of curvature of the first and second spherical annular rings intersect in a union where the angular difference is between the tangents thereof at the junction defines a minimum angle to provide a lens having improved comfort of use and physiological acceptance.

Description

DESIGN OF CONCENTRIC ANULAR RING LENS WITH MINIMUM NGULES BETWEEN ADJACENT ANULAR RING SEGMENTS BACKGROUND OF THE INVENTION 1. - FIELD OF THE INVENTION The present invention relates generally to concentric annular ring lenses with minimal angles between adjacent annular ring segments. More particularly, the invention pertains to concentric annular ring lens designs in which the junctions between the adjacent annular lens rings are quantized and programmable. The present invention provides programmable minimum angles between adjacent annular ring segments on lenses and molds thereof, particularly for spherical lens designs having different radii of curvature, which allows a numerically controlled machine (NOT programmed to machine the segments adjacent annuli and transitions between them on a lens mold The present invention also provides criteria for designing contact lenses having improved comfort of use and physiological acceptance. 2. - DISCUSSION OF THE PREVIOUS TECHNIQUE The present invention pertains to ophthalmic lenses, and in particular to contact lenses such as soft hydrogel contact lenses, and intraocular lenses, having more than one optical power or focal length. It is well known that as an individual ages, the view is less able to accommodate, that is, to direct the natural lens in the eye, in order to focus on objects that are relatively close to the observer. This condition is referred to as presbyopia, and presbyopia has depended in the past on glasses or other lenses that have a number of different regions with different optical powers to which the user can change their vision in order to find the appropriate optical power to the object or objects on which the observer wishes to focus. Patent Application Serial No. 07 / 9ßd, 0 &ß case of attorney VTN 56), entitled PUPIL TUNED MULTIFOCAL OPHTHALMIC LENS, describes a ultifocal concentric ophthalmic lens designed for prebiotic patients that is constituted with three portions of general annular lens in a multifocal design. A circular central portion of the lens has only the corrective power of distance from the patient, and is surrounded by a first internal annular portion, which may consist of multiple annular rings having an internal radial portion that increases the close focal power of the patient surrounded by radial portions of substantially equal cumulative amounts of focal correction of optical distance and closeness correspondence for the patient. It is encircled by a second outer annular portion which may consist of one or more annular rings having focal power of additional distance near the periphery of the optic area of the ophthalmic lens. Each annular ring has either an optical proximity or distance power and works in combination with other portions of the lens to produce the desired focal radius in that portion of the lens. The US Patent of Marie et al of No. 5,106, lft0 describes an ophthalmic lens comprising a plurality of contiguous circular refractive bands provided on at least one of the front and rear optical surfaces. The bands have a continuous cross section in the shape of a segment of an ellipse having a given length and eccentricity of major axis. The bands are of alternating optical power to focus light on at least two focal planes to provide simultaneous multifocal vision. The major axis of each ellipse segment intersects the optical ophthalmic lens center axis and one of the two focal planes. The bands are continuous in their limits with neighboring bands. The complete optical lens surface can be used with minimal distortion caused by the intercepts of the continuous bands. However, this patent does not address or provide concentric annular ring lens designs with minimum angles between adjacent spherical annular ring segments as in the present invention.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is a primary object of the present invention to provide concentric annular ring lens designs with minimal angles between adjacent annular ring segments. A further object of the present invention is to provide multiple focus, concentric annular ring lens designs for use in the correction of astigmatism. A further object of the present invention is the provision of such concentric annular ring lens designs in which the junctions between adjacent annular rings of the lens are quantized and pramorable. The present invention relates in particular to spherical lens designs having different radii of curvature, which allow a numerically controlled machine (NOT to be programmed to machine adjacent annular segments and transitions between them.) An additional object of the present invention. invention is the provision of criteria for designing contact lenses having improved comfort of use and physiological acceptance In accordance with the teachings herein, the invention provides a concentric ring lens of multiple focus designed with a minimum angle on the surface of lens between adjacent annular rings thereof One of the front and rear lens surfaces defines a plurality of spherical annular rings having different spherical optical powers with different spherical radii In accordance with the teachings of the present invention, the radius of the curvature of a first spherical ring or is displaced along the longitudinal optical axis of the lens relative to the radius of curvature of a second adjacent spherical ring. The radii of curvature of the first and second spherical annular rings intersect at a junction wherein the angular difference between the tangents thereof at the junction defines a minimum angle to provide a lens having improved comfort of use and physiological acceptance. In more detail, the radius of curvature of a third spherical annular ring is also displaced along the longitudinal optical axis of the lens relative to the radius of curvature of the second adjacent spherical annular rim. The radii of curvature of the second and third spherical annular rings intersect at a junction between the second and third spherical annular rings and the angular difference between the tangents of the second and third spherical annular rings at the junction defines a minimum angle between them. The plurality of annular rings surrounding a central area comprising a circular disk having a spherical surface corresponding to the optical power of distance Rx of the patient's basic prescription. One of the first and second annular rings has the optical power of spherical distance R? of basic prescription, and the other of the first and second segments of spherical ring ring has an optical power of spherical closeness of prescription of the patient. The lens comprises a contact lens, such as a soft hydrogel contact lens, for use on the cornea of the eye, in which case the plurality of annular rings are preferably formed on the back surface of the contact lens to minimize reflex and glare problems, or an intraocular lens. The widths of the individual annular rings may be different to general a power profile that varies to generate different optical power radii from the first and second annular ring segments.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention for concentric lens designs with minimal angles between adjacent annular segments can be more readily understood by one skilled in the art with reference to the following detailed description of the various preferred embodiments thereof, taken in conjunction with the accompanying drawings in which like elements are designated by identical reference numbers through the different views, and in which: Figure 1 is a plan view of a modality of a lens for which the teachings of the present invention are applicable, having a central area with a circular disk containing the optical power of spherical distance Rx prescribed basic, surrounded by a plurality of ring rings of spherical distance optical power and alternating spherical close optical power; Figure 2 illustrates the trigonometric relationships of the inclination of a spherical curve to a general Cartesian coordinate system x, y; Figure 3 illustrates the general principles of operation of the present invention for providing a transition with a minimum angle between adjacent annular segments of a multifocal concentric annular ring lens; The figure illustrates the displacement along the optical lens axis of alternating radio centers rl and r2 of alternating adjacent annular rings, as would be found in a multifocal annular ring lens as illustrated in Figure 1.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings in detail, Figure 1 illustrates an exemplary embodiment of an annular ring lens 10 which can be designed with minimum angles between adjacent annular rings in accordance with the teachings of a the present invention. A central area 12 of the lens 10 is a circular disk containing the basic prescribed spherical distance power Rx, and is surrounded by a plurality of ring spherical power rings and spherical close power alternating lft, 20, 22 and 21 * . The central circular portion 12 of lens 10 has only the corrective power of distance from the patience to provide the corrective power of distance under conditions of high illumination (when the pupil is contracted). This is surrounded by a relatively large annular first ring capable of providing an improved contribution of near vision optical power to provide an approximately equal amount of near and distant focal length images under intermediate light conditions. It is surrounded by ring rings of alternate distance and distance lé, lfi, 20 and 22 that provide substantially equal cumulative amounts of optical power focal correction of distance and closeness to the patient. This is surrounded by an outer annular ring 21 * which has additional distance focal power near the periphery of the ophthalmic lens optical surface area to provide the improved optical distance power under low illumination conditions. A typical contact lens is usually constituted with a non-optical lenticular area (not shown) outside the optical surface for a total diameter of about 1 mm. Figure 2 illustrates the trigonometric relationships of the inclination of a spherical curve 26 having a radius r for a general Cartesian coordinate system x, y. Considering the geometric relationship of Figure 2, where the angle w from the central optical axis 2ß of the lens towards a point a on a spherical curve 26 is defined by X w = sin-1 (-) r where s = a semicuerda towards the body a. The angle of a tangent (T) to curve 26 at a point a is simply 90 ° or ?? / 2 radians. Figure 3 illustrates the general principles of operation of the present invention for providing a transition with a minimum angle between adjacent annular spherical segments 32, 34 of respective radii rl and r2 interconnecting at a point b on a concentric multifocal lens 30 having a optical axis 36. The angular difference between the tangents to curves 32 and 34 at point b is simply s Csin ~ l (-) - without T i ra Figure 4 illustrates the displacement along the optical axis of the lens 40 of the alternating radius centers of ri and r2 of alternating adjacent annular rings 42, 44 and 46 having alternating radii of rl and r2, as could be found in Annularly multifocal rings as illustrated in Figure 1. In accordance with the teachings of the present invention, the radius of curvature rl of a first spherical annular ring 42 is displaced along the longitudinal optical axis 40 of the lens relative to the curvature radius r2 of a second adjacent spherical ring 44, so that the two spherical curves intercept in the point r2 with a minimum angle. In addition, FIG. 4 also illustrates that the radii of curvature r2 of a third spherical annular ring 46 is offset along the longitudinal optical axis 40 of the lens relative to the radius of curvature r2 of the second adjacent spherical ring 46, so that the two spherical curves intersect at point d with a minimum angle and without graduation. With this arrangement, the radii of curvature of each adjacent pair of annular rings intersects at a junction wherein the angular difference between the tangents thereof at the joint defines a minimum angle to provide a lens having improved comfort of use and physiological acceptance . Obviously, many different modalities of the present invention are possible, with alterations in the number of annular rings, the widths and arrangement of the annular rings, and the optical powers assigned to each of the annular rings. While various embodiments and variations of the invention are described in detail herein for concentric lens designs with minimal angles between adjacent annular segments, it will be apparent that the description and teachings of the present invention will suggest many alternative designs to those experienced in The technique.

Claims (7)

NOVELTY OF THE INVENTION CLAIMS

1. - A mutifocal concentric annular ring lens, designated with a minimum angle on the lens surface between adjacent annular ring segments of lens, comprising: a) said lens having a front surface and an opposite posterior surface, and an optical axis longitudinal extending centrally through lens substantially perpendicular to the front and top surface, and b) one of the front and top and rear surfaces defines a plurality of spherical annular ring segments having different spherical optical powers with different spherical radii, in wherein the radius of curvature of a first spherical annular ring segment is displaced along the longitudinal optical axis of the lens from the radius of curvature of a second adjacent spherical annular ring segment, such that the radii of curvature of the first and second spherical annular ring segments intersect at a junction and the angular different between the tangents of the first and second spherical ring hoop segments in the joint defines a minimum angle between them to provide a lens having improved comfort of use and physiological acceptance.

2. A concentric, multifocal annular ring lens, according to claim 1, further characterized in that the radius of curvature of a third spherical annular ring segment is displaced along the longitudinal optical axis of the lens from the radius of curvature of the second adjacent spherical annular ring segment, so that the radii of curvature of the second and third spherical annular ring segments intercept at a junction between the second and third spherical annular ring segments and the annular difference between the tangents towards the second and third third spherical annular ring segments in the joint define a minimum angle therebetween to provide a lens having improved comfort of use and physiological acceptance.

3. A multifoco concentric ring ring lens according to claim 1, further characterized in that the plurality of annular ring segments encircle a central area comprising a circular disk having a spherical surface corresponding to an optical power of Rx distance in basic prescription of the patient.

4. A multifoco concentric ring ring lens according to claim 1, further characterized in that one of the first and second annular ring segments has an optical power of spherical distance Rx of basic prescription, and the other of the first and second Spherical annular ring segments have a near spherical optical power Rx of prescription.

5. A multifoco concentric annular ring lens according to claim 1, further characterized in that the lens comprises a contact lens for use on the cornea of the eye.

6. A multifoco concentric ring ring lens according to claim 5, further characterized in that the plurality of annular ring segments are formed on the rear surface of the contact lens to minimize the problems of reflection and glare.

7. A multifocal concentric annular ring lens in accordance with the indication 5, further characterized in that the contact lens comprises a soft hydrogel contact lens. & - A multifoco concentric annular ring lens according to claim 1, further characterized in that the lens comprises an intraocular lens. 9. A multifoco concentric annular ring lens according to claim 1, further characterized in that the individual annular ring segment widths are different to generate a power profile that varies to generate different optical power radii from the first and second ring ring segments. DESIGN OF RING LENS CONCENTRIC WITH MINIMAL ANGLES BETWEEN ADJACENT ANNULAR ROPE SEGMENTS. SUMMARY OF THE INVENTION Multifocal concentric ring ring lens designs with minimal angles between adjacent annulus rings are described; The present invention particularly relates to spherical lens designs having different radii of curvature, which allows a numerically controlled machine (NOT to be programmed to machine the adjacent annular segments and the transitions between them, a concentric annular ring lens, The multifoco has either a front or rear surface defining a plurality of spherical annular rings having different spherical optical powers with different spherical radii, in accordance with the teachings of the present invention, the radius of curvature of a first spherical annular ring is displaced along the longitudinal optical axis of the lens relative to the radius of curvature of a second adjacent spherical ring ring, the radii of curvature of the first and second spherical annular rings intersect at a junction where the angular difference is between the tangents of the same in the union defines a minimum angle for eer a lens that has improved comfort of use and physiological acceptance. RM / cgt * mvs *