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EP-4735949-A1 - SPECTACLE LENS, SPECTACLES, COMPUTER-IMPLEMENTED METHOD FOR DESIGNING A SPECTACLE LENS AND METHOD FOR PRODUCING A SPECTACLE LENS

EP4735949A1EP 4735949 A1EP4735949 A1EP 4735949A1EP-4735949-A1

Abstract

The invention relates to a spectacle lens (1) comprising - a spectacle lens rear surface (11) facing towards the eye; - a spectacle lens front surface (13) facing away from the eye; - a Fresnel structure (3) comprising at least two Fresnel zones (3-1 to 3-6) providing a focusing effect, wherein the focusing effect of the Fresnel structure (3) is based at least partially on a refractive index gradient within the Fresnel zones (3-1 to 3-6), and the Fresnel structure (3) has boundary surfaces (5a to 5e) at which a high refractive index of one Fresnel zone (3-1 to 3-6) and a low refractive index of an adjacent Fresnel zone (3-1 to 3-6) adjoin one another. The at least one boundary surface (5a to 5e) has a rear-side intersection line (4a to 4e) with the spectacle lens rear surface (11) and a front-side intersection line (6a to 6e) with the spectacle lens front surface (13). The rear surface region of the spectacle lens rear surface (11) enclosed by the innermost rear-side intersection line (4a) has a rear-side geometric centre of gravity (RS) and the front-side surface region of the spectacle lens front surface (11) enclosed by the innermost front intersection line (6a) has a front-side geometric centre of gravity (VS). The rear-side intersection line (4a to 4e) has a smaller distance from the rear-side geometric centre of gravity (RS) than the front-side intersection line (6a to 6e) from the front-side geometric centre of gravity (VS), for at least 25% of all azimuth angles.

Inventors

  • MUENZ, HOLGER
  • HENSEL, Rene
  • Scheiderer, Philipp

Assignees

  • Carl Zeiss AG

Dates

Publication Date
20260506
Application Date
20240619

Claims (20)

  1. 1. Spectacle lens (1) with a rear lens surface (11) facing the eye; a front lens surface (13) facing away from the eye; a Fresnel structure (3) comprising at least two Fresnel zones (3-1 to 3-6) which provides a focusing effect, wherein the focusing effect of the Fresnel structure (3) in at least one of the Fresnel zones (3-1 to 3-6) is based at least partially on a gradient of the refractive index within and the Fresnel structure (3) has interfaces (5a to 5e) at which a high refractive index of a Fresnel zone (3-1 to 3-6) and a low refractive index of an adjacent Fresnel zone (3-1 to 3-6) adjoin one another, wherein the at least one interface (5a to 5e) has a rear-side intersection line (4a to 4e) with the rear surface of the spectacle lens (11) and a front-side intersection line (6a to 6e) with the front surface of the spectacle lens (13); the rear surface region of the lens rear surface (11) enclosed by the innermost rear cutting line (4a) has a rear geometric center of gravity (RS) and the front surface region of the lens front surface (11) enclosed by the innermost front cutting line (6a) has a front geometric center of gravity (VS); characterized in that the rear cutting line (4a to 4e) has a smaller distance from the rear geometric center of gravity (RS) for at least 25% of the azimuth angles than the front cutting line (6a to 6e) from the front geometric center of gravity (VS).
  2. 2. Spectacle lens (1) according to claim 1, characterized in that at least one boundary surface (5a to 5e) is aligned such that those rays (9-1 to 9-5) which run within a cutting plane along this boundary surface (5a to 5e) unite after exiting the rear surface of the lens (11) in a point (PM, AD) lying on the side of the rear surface of the lens (11) and spaced therefrom, wherein the cutting plane is a plane in which there is a front-side connecting line running at a specific azimuth angle in the front surface of the lens (13) which connects the geometric center of gravity (VS) of the enclosed front surface area by the shortest path to a point on the front-side cutting line (6a to 6e) of one of the boundary surfaces (5a to 5e), and in which there is also a rear-side connecting line running at the same specific azimuth angle in the rear surface of the lens (11) which connects the geometric center of gravity (RS) of the enclosed rear surface area by the shortest path to a point on one of the rear cutting lines (4a to 4e) of the same interfaces (5a to 5e).
  3. 3. Spectacle lens (1) according to claim 2, characterized in that the point (PM, AD) located on the side of the rear surface of the spectacle lens (11) and spaced therefrom is the same for all azimuth angles.
  4. 4. Spectacle lens (1) according to claim 2, characterized in that the distance of the point (PM, AD) lying on the side of the spectacle lens rear surface (11) and spaced therefrom from the spectacle lens rear surface (11) depends on the azimuth angle.
  5. 5. Spectacle lens (1) according to one of claims 2 to 4, characterized in that at least two of the boundary surfaces (5a to 5e) are aligned in such a way that, for the respective boundary surface (5a to 5e), all rays (9-1 to 9-5) running within the cutting plane along this boundary surface (5a to 5e) after exiting the spectacle lens rear surface (11) are directed into a beam lying on the side of the spectacle lens rear surface (11) and spaced apart from this point (PM, AD), and the point (PM, AD) located on the side of the rear surface of the spectacle lens (11) and spaced therefrom is the same for the at least two boundary surfaces (5a to 5e).
  6. 6. Spectacle lens (1) according to one of claims 2 to 5, characterized in that at least two of the interfaces (5a to 5e) are aligned such that, for the respective interface (5a to 5e), all rays (9-1 to 9-5) running within the cutting plane along this interface (5a to 5e) after exiting the spectacle lens rear surface (11) combine in a point (PM, AD) located on the side of the spectacle lens rear surface (11) and spaced therefrom, and the distance of the point (PM, AD) located on the side of the spectacle lens rear surface (11) and spaced therefrom from the spectacle lens rear surface (11) is different for the at least two interfaces (5a to 5e).
  7. 7. Spectacle lens according to one of claims 2 to 6, characterized in that at least one of the boundary surfaces (5a to 5e) runs along a straight line within the cutting plane.
  8. 8. Spectacle lens (1) according to one of claims 2 to 7, characterized in that at least one of the interfaces (5a to 5e) runs within the cutting plane along a curved line, the curvature of which is a curvature that follows the course of a light beam (9a) that emanates from the point (PM, AD) spaced from the spectacle lens rear surface (13) and enters the spectacle lens (1) at the boundary between the high refractive index of one Fresnel zone (3-1 to 3-6) and the low refractive index of the adjacent Fresnel zone (3-1 to 3-6) through the spectacle lens rear surface (11) immediately adjacent to the interface (5a to 5e) on the side of the high refractive index; or is a curvature that follows the course of a light beam (9b) that emanates from the point spaced from the spectacle lens rear surface (13) (PM, AD) and enters the spectacle lens (1) at the boundary between the high refractive index of one Fresnel zone (3-1 to 3-6) and the low refractive index of the adjacent Fresnel zone (3-1 to 3-6) through the rear surface (11) of the spectacle lens immediately adjacent to the boundary surface (5a to 5e) on the side of the low refractive index; or a curvature whose course lies between the courses of the said light rays (9a, 9b).
  9. 9. Spectacle lens (1) according to one of claims 2 to 8, characterized in that the spectacle lens (1) is designed as a negative lens and has a dead zone (15) for each interface (5a to 5e) which is delimited by the course of a set of first light rays (9a) in the spectacle lens (1), by the course of a set of second light rays (9b) in the spectacle lens (1) and by an annular region (14) of the front surface (13) of the spectacle lens resulting from the course of the first set of light rays (9a) and the course of the second set of light rays (9b), wherein the first light rays (9a) are those light rays (9) which emanate from the point (PM, AD) spaced from the rear surface (11) of the spectacle lens and pass through the rear surface (11) of the spectacle lens immediately adjacent to the corresponding interface (5a to 5e) into the Fresnel zone (3-1 to 3-6) with the light beam directed to the interface. (5a to 5e) adjacent high refractive index, and the second light rays (9b) are those light rays (9) which emanate from the point (PM, AD) spaced from the rear surface of the lens (11) and enter through the rear surface of the lens (11) immediately adjacent to the corresponding interface (5a to 5e) into the Fresnel zone (3-1 to 3-6) with the low refractive index adjacent to the interface (5a to 5e), and the respective dead zones (15) are each provided with at least one light-absorbing layer (17).
  10. 10. Spectacle lens (1) according to claim 7 and claim 9, characterized in that at least one of the boundary surfaces (5a to 5e) runs along a straight line within the cutting plane and this straight line is aligned such that it runs at least partially within the dead zone (15).
  11. 11. Spectacle lens (1) according to claim 9 or claim 10, characterized in that the dead zones (15) of the spectacle lens (1) have a different refractive index than the high refractive index and the low refractive index of the Fresnel zones (3-1 to 3-6) adjacent to the respective dead zone (15).
  12. 12. Spectacle lens (1) according to one of claims 1 to 11, characterized in that it has a central region (23) without a Fresnel structure (3) and with a curved surface and the Fresnel structure (3) is only present in a region outside the central region (23), wherein the spectacle lens (1) provides a focusing effect in the central region (23) due to the curved surface and in the edge region due to the Fresnel structure (3).
  13. 13. Spectacle lens (1) according to one of claims 1 to 12, characterized in that an additional Fresnel structure (20) with Fresnel facets (20-1 to 20-6) having curved surfaces is formed on the spectacle lens front surface (13) or the spectacle lens rear surface (11) and has jumps in the arrow height on the front cutting lines (6a to 6e) or the rear cutting lines (6a to 6e).
  14. 14. Spectacle lens (1) according to claim 2 and claim 13, characterized in that the jumps in the sagittal angles are formed by flanks (21a to 21e) of the Fresnel facets (20-1 to 20-6) which continue the course of the boundary surfaces (5a to 5e).
  15. 15. Spectacle lens (1) according to one of claims 1 to 14, characterized in that it has a spectacle lens front surface (13) and/or a spectacle lens rear surface (11) which has a bend (18a to 18e) at the boundaries between two Fresnel zones (3-1 to 3-6).
  16. 16. Spectacle lens (1) according to one of claims 1 to 15, characterized in that at least two materials are combined in such a way that color errors are at least partially compensated.
  17. 17. Spectacle lens (1) according to one of claims 1 to 16, characterized in that at the high refractive index there is a low dispersion and at the low refractive index there is a high dispersion
  18. 18. Computer-implemented method for designing a spectacle lens according to one of claims 1 to 17, characterized by Acquiring at least correction data which represent the correction to be achieved with the spectacle lens (1) and distance data which represent at least the distance of the pupil center (PM) or the eye rotation point (AD) from the vertex of the rear surface of the spectacle lens (11) or from which at least the distance of the pupil center (PM) or the eye rotation point (AD) from the vertex of the rear surface of the spectacle lens (11) can be derived; Determining the Fresnel structure (3) on the basis of at least the correction data and the distance data.
  19. 19. Computer-implemented method according to claim 18, characterized by a step of detecting the corneal-vertex distance.
  20. 20. Computer-implemented method according to claim 18 or 19, characterized by a step of outputting a numerical Representation of the designed spectacle lens (1) for use in the manufacture of an actual spectacle lens (1) corresponding to the numerical representation of the spectacle lens (1) by means of a computer-aided numerically controlled manufacturing process.

Description

Spectacle lens, spectacles, computer-implemented method for designing a spectacle lens and method for producing a spectacle lens The present invention relates to a spectacle lens with a Fresnel structure providing a focusing effect. In addition, the invention relates to a computer-implemented method for designing such a spectacle lens and a method for producing such a spectacle lens. Conventional lenses become thicker and heavier the higher the level of vision correction required. In addition to the choice of material, weight reduction is achieved primarily by reducing the size, i.e. by choosing a smaller frame. The weight is particularly relevant for applications for vision correction in the field of augmented reality (so-called AR glasses), since the system weight is already significantly higher than that of a classic lens due to the additional components such as light guides, cameras, sensors, etc. However, a reduction in the diameter is often not a viable option here due to the necessary size of the light guides to reflect the virtual image into the wearer's field of vision. For example, Fresnel structures for reducing the weight of spectacle lenses are known from EP 0 927 905 A, GB 1 , 154,360 A, JP 2019174647 A and US 2013/0120707 A1. However, Fresnel structures are challenging to manufacture due to sharp steps. In addition, the susceptibility of exposed Fresnel structures to contamination makes an additional Covering/filling them is necessary. In addition, the steps of Fresnel structures lead to shadowing effects and scattered light. WO 2018/134037 A2 also discloses gradient index lenses (GRIN lenses) for ophthalmic applications, but these do not offer any weight advantages over classic glass with a constant refractive index. US 2022/0252931 A1 shows a segmented liquid crystal optic that can be used as a Fresnel GRIN lens with variable refractive power in augmented reality devices. Fresnel-GRIN lenses, i.e. lenses in which the Fresnel structure is realized by variations in the refractive index, are known from the literature on micro-optics for coupling light into optical fibers. Examples of publications on micro-optical Fresnel-GRIN lenses are, for example, from Suhara et al., "Graded-index Fresnel lenses for integrated optics”, Appl. Opt. 21 (1982), pp. 1966-1971 ; P. Dellulier et al., "Femtosecond Laser Direct Writing of Gradient Index Fresnel Lens in GeS2-Based Chalcogenide Glass for Imaging Applications”, Appl. Sci 12 (2022), 4490; and R. Buczynski et al. R 2019, 'Achromatic nanostructured gradient index microlenses', Optics Express, vol. 27, no. 7, pp. 9588-9600. The Fresnel-GRIN lenses described therein are designed for use in the infrared spectral range. Diffractive Fresnel-GRIN lenses are known from A. Zhang, “Multifocal diffractive lens design in ophthalmology”, Applied Optics, Vol. 59, No. 31 (1 November 2020), pp. 9807- 9823. Diffractive Fresnel-GRIN lenses are used, for example, in intraocular lenses to create another point of sharp vision, given by the diffractive effect of the Fresnel structure, in addition to the refractive focal point given by the geometric shape of the intraocular lens. This enables the intraocular lens to enable sharp vision at different distances. Contact lenses designed as Fresnel-GRIN lenses are known from WO 97/10527 A1. Compared to the prior art mentioned, a first object of the present invention is to provide an advantageous spectacle lens and advantageous spectacles with a Fresnel structure that provides a focusing effect, in which the focusing effect of the Fresnel structure is based at least partially on a gradient of the refractive index within the Fresnel zones. The term "focusing effect" in the sense of the invention according to DIN EN ISO 13666:2019-12, Section 3.10.2 is a collective term for the spherical and astigmatic vertex power of a spectacle lens, which in turn is the reciprocal of the paraxial focal length of the spectacle lens according to DIN EN ISO 13666:2019-12, Section 3.10.7. A second object of the present invention is to provide a computer-implemented method for designing a spectacle lens as well as a computer program and a computer for carrying out the method. Finally, a third object of the present invention is to provide an advantageous method for producing a spectacle lens. The first object is achieved by a spectacle lens according to claim 1 and by spectacles according to claim 26, the second object by a computer-implemented method according to claim 18 and the third object by a method according to claim 25. The dependent claims contain advantageous embodiments of the invention. According to a first aspect of the invention, a spectacle lens is provided. The term "spectacle lens" is intended to include both unprocessed round spectacle lenses and spectacle lenses adapted to a spectacle frame. In addition, the term "spectacle lens" is also intended to include numerical representations of spectacle lenses. A spectacle lens according to