Method and system for providing a pattern on a spectacle lens substrate and spectacle lens

Abstract

The invention relates to a method and a system for printing a pattern (22) on an spectacle lens substrate (20) arranged on a carrier (18). According to the invention, a filament (36) in extruding a thermoplastic material (28) having a semi-molten state through a nozzle (32) is provided for depositing said filament (36) on curved surface (34) of said spectacle lens substrate (20).

Description

[0001] u - 1 - Method and system for providing a pattern on a spectacle lens substrate and spectacle lens

[0002] Specification

[0003] The invention relates to a method and system for providing a pattern on a spectacle lens substrate arranged on a carrier. The invention also relates to a spectacle lens.

[0004] In this context, a spectacle lens substrate is a component that can be penetrated by light. A spectacle lens in the sense of the invention is defined as in ISO 13666:2019(E), entry 3.5.2.

[0005] WO 2020 / 078964 A1 discloses the application of an abrasion-resistant coating by means of additive manufacturing to an optical element substrate. In particular, this publication describes the arrangement of optical components, which are produced by means of additive manufacturing such as inkjet or spraying, on the coating of an optical element substrate, e.g. a spectacle lens substrate. The optical components can be any kind of optical components such as microelements, discrete islands or slots, ribs or rings having macroscopic scale and protruding from the base surface of an abrasion-resistant coating.

[0006] WO 2020 / 064728 A1 discloses a method for printing a thermoplastic film on an optical mold. WO 2014 / 108364 A1 describes a system and method for printing an optical element. WO 2023 / 036904 A1 discloses a system for printing a pattern on the curved surface of a spectacle lens substrate. US 100051262 B2 describes a system for manufacturing an object including an extruder for one or mor deposition materials. WO 2020 / 169837 A1 discloses manufacturing an optical element from a curable material by juxtaposing volume elements of the curable material. The object of the invention is to provide a method and a system that make it possible to manufacture a spectacle lens having spatially extended structures with a predetermined geometry.

[0007] This object is achieved by the method defined in claim 1 and the system defined in claim 9.

[0008] Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0009] The method for providing a pattern on a spectacle lens substrate arranged on a carrier, as recited in claim 1 , includes providing a filament by extruding a thermoplastic material in a semi-molten state through a nozzle and depositing the filament on a curved surface of the spectacle lens substrate.

[0010] Preferably the nozzle has a nozzle opening from which the filament emerges during the extrusion of the thermoplastic material, and the nozzle opening is moved relative to the spectacle lens substrate during the extrusion of the thermoplastic material through the nozzle in three spatial directions that span a three-dimensional space.

[0011] It is advantageous to adjust a local height of the nozzle opening of the nozzle above the spectacle lens substrate as a function of the position of a vertical projection of the nozzle opening of the nozzle on the spectacle lens substrate.

[0012] In particular, it is advantageous to adjust a position of the nozzle opening of the nozzle relative to the spectacle lens substrate as a function of at least one optical property of the spectacle lens substrate.

[0013] The invention is based on the realization that Fused Deposition Modeling (FDM) is one of the most extensively used techniques for 3D manufacturing of objects, in which thermoplastic materials are extruded through a nozzle tip, heated to a semi molten state and then deposited planar onto the substrate layer-by-layer, leaving behind a 3D object when the material has solidified. The object is built by stacking these layers in the z-direction.

[0014] Unlike conventional additive manufacturing processes, which rely on layer-by-layer deposition of material on planar substrates, the invention allows to deposit material on existing spectacle lenses or optical components with non-planar surfaces.

[0015] This is achieved through precise control of the additive manufacturing process, including material deposition parameters, spectacle lens parameters and computer-aided software. By strategically depositing the material along the lens shape, complex / hybrid spectacle lenses can be realized, offering design freedom and customization.

[0016] Favorable parameters for material deposition include a nozzle temperature Tn, for which the following relationship applies depending on the material to be deposited: 150°C < Tn < 250°C, e.g. Tn « 235°C.

[0017] The height of an applied layer is advantageously 0.02 mm to 0.3 mm, e.g. 0.3 mm. The height of an applied layer can be constant or can be changed in order to set a desired shape. The width of a strand of material supplied by the nozzle can be in the range of 0.4 mm during application.

[0018] The printing speed, i.e. the speed at which a nozzle opening moves relative to the carrier material of the spectacle lens, can be between 10 mm / s and 60 mm / s, for example, and is preferably 20 mm / s, whereby the following applies to the volume flow Jvfrom the nozzle: Jv« 2 mm3 / s.

[0019] The proposed method utilizes non-planar (curved layer) additive manufacturing (FDM) to overcome the axis limitations, enabling the deposition of materials into non planar surfaces (spectacle lenses) with curved, freeform, or irregular surfaces. The z height is actively changing its position in the same layer to match the curved substrate profile.

[0020] In order to achieve such results, the thickness and the front- and / or back curve of a spectacle lens substrate, e.g. a lens substrate, in particular a spectacle lens substrate must be known, then with a computer aided solution, it is possible to manually or by algorithm adjust the z coordinate including a specific offset for the pattern to be deposited onto the spectacle lens substrate to follow the curvature of the lens, in a single layer. The spectacle lens must be placed in a known coordinate system. It can be aligned automatically by using engraving orientation marks and camera recognition. The material is then deposited onto the non-planer spectacle lens substrate surface in a controlled manner, following the predetermined non planar path.

[0021] The resulting hybrid spectacle lenses exhibit enhanced performance characteristics and are suitable for various applications in optics, e.g. selective tinting, myopia management, complex geometries features, etc.

[0022] The invention proposes that the local height of the nozzle opening of the nozzle above the spectacle lens substrate be kept constant during the extrusion of the thermoplastic material through the nozzle. A special feature of the invention is that the local height of the nozzle opening of the nozzle above the spectacle lens substrate is varied during the extrusion of the thermoplastic material through the nozzle.

[0023] In particular, the invention comprises the idea that the filament deposited on the surface of the spectacle lens substrate changes a local optical property of the spectacle lens substrate.

[0024] The invention also extends to an ophthalmic lens, e.g. a spectacle lens fabricated by a method recited above. The ophthalmic lens may comprise a pattern and a spectacle lens substrate, wherein the pattern is printed on the lens substrate using a method as defined above.

[0025] The invention enables the manufacture of spectacle lenses which have a defocusing area and / or a peripheral blur and / or a certain peripheral refractive power. A blurring effect can be achieved by any structure without changing the meaning of the refractive power used to describe spectacle lenses.

[0026] The applied material may or may not have the same refractive index as the spectacle lens substrate or it may have a different color / material. In particular, the invention makes it possible to produce spectacle lenses with a refractive power Bk for which the following applies: 0 < Bk 10D.

[0027] The material may be applied on a surface of a finished spectacle lens, the finished lens as defined in ISO 13666:2019(E), entry 3.8.7, the finished spectacle lens being either an uncut spectacle lens or an edged spectacle lens, the uncut spectacle lens as defined in ISO 13666:2019(E), entry 3.8.8, the edged spectacle lens as defined in ISO 13666:2019(E), entry 3.8.9. The surface of the spectacle lens or of the finished spectacle lens is a front surface or a back surface, the front surface as defined in ISO 13666:2019(E), entry 3.2.13, the back surface as defined in ISO 13666:2019(E), entry 3.2.14. The material may be applied on the surface of the finished spectacle lens according to a pattern that is assumed to prevent a progression of myopia. The material may be applied on the surface of the finished spectacle lens, for example, by a system for printing, preferably as described below, at a spectacle lens manufacturers site, an optician, an eye care professional etc.

[0028] A system for printing a pattern on a curved surface of an spectacle lens substrate disposed on a carrier as defined in claim 9 includes means for providing a filament while extruding a thermoplastic material that is in a semi-molten state through a nozzle and depositing the filament onto the surface of the spectacle lens substrate. Preferably the nozzle has a nozzle opening from which the filament emerges during the extrusion of the thermoplastic material and means are provided to move the nozzle opening during the extrusion of the thermoplastic material through the nozzle relative to the substrate in three spatial directions that span a three-dimensional space.

[0029] An idea of the invention is that means are provided for varying the local height h of the nozzle orifice of the nozzle above the carrier as a function of the position of a vertical projection of the nozzle opening of the nozzle on the spectacle lens substrate.

[0030] In particular, the system may include means for adjusting a position of the nozzle opening of the nozzle relative to the spectacle lens substrate as a function of at least one optical property of the spectacle lens substrate.

[0031] The system for printing a pattern on a curved surface of an spectacle lens substrate disposed on a carrier may have means for varying the local distance d of the nozzle opening of the nozzle from the spectacle lens substrate during extrusion of the thermoplastic material through the nozzle. Preferably, the filament deposited on the surface of the spectacle lens substrate modifies a local optical property of the spectacle lens substrate.

[0032] The system may include means for adjusting a local height d of the nozzle opening of the nozzle above the substrate as a function of the position of a vertical projection of the nozzle opening of the nozzle on the spectacle lens substrate.

[0033] In particular, the system may include means for adjusting a position of the nozzle opening of the nozzle relative to the spectacle lens substrate as a function of at least one optical property of the lens substrate. In particular, it is an idea of the invention that the filament deposited on the surface of the lens substrate modifies a local optical property of the lens substrate.

[0034] The invention is explained in more detail below with reference to the schematic embodiments shown in the drawings.

[0035] It shows:

[0036] Fig. 1 a system in a first state of operation for printing a pattern on a curved surface of an spectacle lens substrate arranged on a carrier production including means for providing a filament in extruding a thermoplastic material having a semi-molten state through a nozzle and depositing said filament on said surface of said spectacle lens substrate;

[0037] Fig. 2 the system of Fig. 1 in another state of operation;

[0038] Fig. 3 a relative displacement of the nozzle to the substrate, wherein the distance of the nozzle to the spectacle lens substrate is adjusted;

[0039] Fig. 4 a lens substrate having a first structure printed thereon by means of the system;

[0040] Fig. 5 an spectacle lens substrate having a second structure printed thereon by means of the system; and

[0041] Fig. 6 an spectacle lens substrate having a third structure printed thereon by means of the system.

[0042] The system 10 for printing shown in Fig. 1 has an extruder 12 with an extruder housing 14 that has a heating device (not shown) and in which a conveyor screw 16 is arranged. The system 10 has a carrier 18 which is workpiece table for arranging a workpiece in the form of a spectacle lens substrate 20. The substrate 20 has a curved surface 34 on which a filament pattern 22 is to be applied. Fig. 1 shows the system in a first operating state. In the present case, the spectacle lens substrate 20 is a lens substrate.

[0043] The conveyor screw 16 in the system 10 can be moved around a screw axis 24 by means of a motorized drive 26. By rotating the conveyor screw 16 around the screw axis 24, it is possible to apply pressure to thermoplastic material 28 from a material feed container 30 and to continuously press it through a nozzle 32, thus providing a filament 36 made of the thermoplastic material. The system 10 includes a motorized adjustable positioning arrangement 33 which allows to move the extruder 12 including the nozzle 32 having the nozzle opening 31 in three spatial directions x, y and z.

[0044] Fig. 2 shows the system 10 for printing, in which the nozzle 32 is displaced relative to the workpiece table 18 in the spatial directions x, y and z.

[0045] By being able to displace the nozzle 32 of the system 10 relative to the workpiece table 18 for arranging a lens substrate 20 in the mutually perpendicular spatial directions x, y, z, a nozzle opening 31 from which the filament 36 emerges during extrusion of the thermoplastic material 28 is moved relative to the spectacle lens substrate 20 in three spatial directions x, y and z spanning a three-dimensional space during extrusion of the thermoplastic material 28 through the nozzle 32.

[0046] The motorized adjustable positioning arrangement 33 comprises an open and closed loop control 35. The open and closed loop control 35 is adapted for adjusting a local height h of the nozzle opening 31 of the nozzle 32 above the carrier 18 as a function of the position of a vertical projection of the nozzle opening 31 of the nozzle on the substrate 20. By means of the open and closed loop control 35, the positioning arrangement 33 can be adjusted in a way that the local distance d of the nozzle opening 31 of the nozzle 32 from the spectacle lens substrate 20 above the spectacle lens substrate 20 during extrusion of the thermoplastic material 28 through the nozzle 32 can be kept constant, while the nozzle opening 31 is being relocated in the xy plane. In the alternative, the local distance d of the nozzle opening 31 of the nozzle 32 above the spectacle lens substrate 20 during extrusion of the thermoplastic material 28 through the nozzle 32 may also be varied.

[0047] By means of the motorized adjustable positioning arrangement 33 it can be achieved that the extrusion of the thermoplastic material 28 from the material feed container 30 can be applied to the surface 34 of the spectacle lens substrate 20 on the workpiece table and can be precisely laid on the surface 34 of the spectacle lens substrate 20. It is to be remarked that the position of the nozzle opening 31 of the nozzle 32 relative to the spectacle lens substrate 20 may also be varied as a function of one or more optical properties of the spectacle lens substrate 20.

[0048] Fig. 3 is a three-dimensional view of the nozzle 32 and the spectacle lens 20 and shows a filament 36 laid on the lens substrate by relative displacement of the nozzle 32 of the system for printing to the spectacle lens substrate 20.

[0049] Fig. 4 shows a filament pattern 22 formed by a filament 36 on a spectacle lens laid on the spectacle lens substrate 20 in the form of a spiral. Fig. 5 shows a filament pattern 22’ formed by a filament 36 which is laid on the spectacle lens substrate 20 in the form of a starfish. Fig. 6 shows a filament pattern 22” made of filaments 36 laid on the spectacle lens substrate 20 in the form of a star pattern.

[0050] To summarize, the following preferred features of the invention should be noted in particular: The invention relates to a method and a system for printing a pattern 22, 22’, 22” on an spectacle lens substrate 20 arranged on a carrier 18. A filament 36 in extruding a thermoplastic material 28 having a semi-molten state through a nozzle 32 is provided for depositing said filament 36 on curved surface 34 of said spectacle lens substrate 20. List of reference symbols:

[0051] 10 system

[0052] 12 extruder

[0053] 14 extruder housing

[0054] 16 conveyor housing

[0055] 18 workpiece table

[0056] 20 spectacle lens substrate

[0057] 22 filament structure

[0058] 24 screw axis

[0059] 26 drive

[0060] 28 thermolastic material

[0061] 30 material feed container

[0062] 31 nozzle opening

[0063] 32 nozzle

[0064] 33 positioning arrangement 34 surface

[0065] 35 open and closed-loop control 36 filament

Claims

Claims1. A method for printing a pattern (22, 22’, 22”) on an spectacle lens substrate (20) arranged on a carrier (18), characterized by providing a filament (36) in extruding a thermoplastic material (28) having a semi-molten state through a nozzle (32) and depositing said filament (36) on a curved surface (34) of the spectacle lens substrate (20).

2. The method of claim 1 , characterized by that the nozzle (32) has a nozzle opening (31 ) from which the filament (36) emerges during extrusion of the thermoplastic material (28), and the nozzle opening (31 ) is moved relative to the spectacle lens substrate (20) in three spatial directions spanning a three-dimensional space during extrusion of the thermoplastic material (28) through the nozzle (32).

3. The method of one of the claims 1 or claim 2, characterized by that a local height (h) of the nozzle opening (31 ) of the nozzle (32) above the carrier (18) is adjusted as a function of the position of a vertical projection of the nozzle opening (31 ) of the nozzle (32) on the surface (34) of the spectacle lens substrate (20).

4. The method of one of the claims 1 to 3, characterized by that a position of the nozzle opening (31 ) of the nozzle (32) relative to the spectacle lens substrate (20) is adjusted as a function of at least one optical property of the spectacle lens substrate (20).

5. The method of one of the claims 1 to 4, characterized by that the local distance (d) of the nozzle opening (31 ) of the nozzle (32) from the spectacle lens substrate (20) during extrusion of the thermoplastic material (28) through the nozzle (32) is kept constant.

6. The method of one of the claims 1 to 5, characterized by that the local height h of the nozzle opening (31 ) of the nozzle (32) above the spectaclelens substrate (20) during extrusion of the thermoplastic material (28) through the nozzle (32) is varied.

7. The method of one of the claims 1 to 6, characterized by that the filament (36) deposited on the surface (34) of the spectacle lens substrate (20) modifies a local optical property of the spectacle lens substrate (20).

8. Spectacle lens comprising a pattern (22, 22’, 22”) and a spectacle lens substrate (20), said pattern (22, 22’, 22”) being printed on said spectacle lens substrate (20) using a method as defined in one of the claims 1 to 7.

9. A System for printing a pattern (22, 22’, 22”) on a curved surface (34) of a spectacle lens substrate (20) arranged on a carrier (18), characterized by means for providing a filament (36) in extruding a thermoplastic material (28) having a semi-molten state through a nozzle (32) and depositing said filament (36) on said surface of said spectacle lens substrate (20).

10. The system of claim 9, characterized by that the nozzle (32) has a nozzle opening (31 ) from which the filament (36) emerges during extrusion of the thermoplastic material (28) and by that means for moving said nozzle opening (31 ) relative to the spectacle lens substrate (20) in three spatial directions spanning a three-dimensional space during extrusion of the thermoplastic material (28) through the nozzle (32) are provided.11 . The system of claim 9 or claim 10, characterized by means for adjusting a local height (h) of the nozzle opening (31 ) of the nozzle (32) above the carrier (18) as a function of the position of a vertical projection of the nozzle opening (31 ) of the nozzle (32) on the spectacle lens substrate (20).

12. The system of one of the claims 9 to 11 , characterized by means for adjusting a position of the nozzle opening (31 ) of the nozzle (32) relativeto the spectacle lens substrate (20) as a function of at least one optical property of the spectacle lens substrate (20).

13. The system of claim 12, characterized by means for varying the local distance (d) of the nozzle opening (31 ) of the nozzle (32) from the spectacle lens substrate (20) during extrusion of the thermoplastic material (28) through the nozzle (32).

14. The system of one of the claims 8 to 13, characterized by that the fila- ment (36) deposited on said surface (34) of the spectacle lens substrate (20) modifies a local optical property of the spectacle lens substrate (20).

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