EP-4739493-A1 - METHOD OF MANUFACTURING A COPY MOULD FOR AN OPTICAL ELEMENT

Abstract

A method is provided for manufacturing of moulds for manufacturing of an optical element. A master of the optical element is manufactured using a precising material deposition technology, like three-dimensional printing, for example on a substrate. Next, a master mould part is manufactured by casting a mould material on the deposited master. The master mould part is used for manufacturing of a master copy, by casting a master copy substance in the cavity of the master mould. The master copy substance may be different from the master substance. Next, a copy mould part is manufactured by casting a mould material on the master copy. The copy mould part is preferably part of a larger mould, with two or more parts and is used for manufacturing of the optical element by combining mould parts to provide a cavity for the casting of the optical element.

Inventors

• BISKOP, Gregorius Petrus Franciscus
• HOFMAN, Julius
• HAGE, Catherine Cornelia Johanna

Assignees

• Addoptics B.V.

Dates

Publication Date

20260513

Application Date

20240705

Claims (20)

1. 1. A method of manufacturing a copy mould for an optical element, the method comprising: receiving, in a three-dimensional printing system, a dataset providing a three-dimensional representation of the optical element; depositing on a substrate, by the three-dimensional printing system, an amount of master substance to provide at least part of a master piece in accordance with at least part of the dataset; providing, on the substrate, a master formwork around the master piece; providing a first amount of mould substance in the master formwork; allowing the first amount of mould substance to settle, thus forming a master mould comprising a master cavity, the master cavity being at least partially defined by the master piece; separating the master piece from the master mould; casting a master copy substance in the master cavity of the master mould to provide a master copy; allowing the master copy substance to settle; removing the master copy from the master mould; providing a copy formwork around the master copy; providing a second amount of mould substance in the copy formwork; allowing the second amount of mould substance to settle, thus forming a copy mould comprising a copy cavity, the copy cavity being at least partially defined by the master copy.
2. 2. The method according to claim 1, the method further comprising, prior to providing a first amount of mould substance, applying an alignment module to the substrate.
3. 3. The method according to claim 2, further comprising providing, by means of at least part of the alignment module, at least one master alignment marker to the master copy.
4. 4. The method of claim 3, further comprising, by means of the master alignment marker, providing a copy mould marker to the copy mould.
5. 5. The method according to claim any one of the claims 2 to 4, wherein the substrate has a rectangular shape and the substrate comprises a hole near each of the four corners, and applying the alignment module comprises providing a rod in each of the four holes in the corners.
6. 6. The method according to claim 5, wherein removing the master piece from the master mould comprises removing the rods from the holes in the substrate, the rods being connected to the master mould after removal of the rods from the substrate.
7. 7. The method according to any one of the preceding claims, the master formwork comprising a set of walls having in orientation substantially perpendicular to the substrate; and a lid having an orientation substantially parallel to the substrate.
8. 8. The method according to claim 7, wherein, after settling of the first amount of mould substance and removal of the master formwork, the lid is connected to the master mould.
9. 9. The method according to any one of the preceding claims, wherein the master formwork has a master formwork footprint that is larger than a substrate footprint of the substrate and the method further comprises providing a casting ground provided under the substrate while providing the first amount of mould substance.
10. 10. The method according to any one of the preceding claims, wherein the copy formwork has a copy formwork footprint outline that is smaller than a substrate footprint outline of the substrate; and the amount of master substance deposited has an object footprint outline that is smaller than the copy formwork footprint outline.
11. 11. The method according to claim 10 to the extent dependent on claim 3, wherein the copy formwork footprint is larger than an area of the master copy defined by holes in the master copy, which holes are defined by the rods in the master mould.
12. 12. The method according to any of the preceding claims, further comprising subjecting the master copy to a surface treatment.
13. 13. The method according to claim 12, wherein the surface treatment is applied after the master copy has been removed from the master mould.
14. 14. The method according to any one of claim 12 and claim 13, wherein the surface treatment comprises at least one of milling and applying a coating to the master copy.
15. 15. The method according to anyone of the preceding claims, further comprising, prior to providing the first amount of mould substance, providing a master mould skeleton around the deposited amount of master substance.
16. 16. The method according to claim 15, wherein the master mould skeleton comprises at least one of an organic polymer and a metal.
17. 17. The method according to any one of the preceding claims, wherein the first amount of mould substance and the second amount of mould substance comprise an elastomer, for claim silicon rubber.
18. 18. The method according to anyone of the preceding claim, wherein the master copy material comprises a polyurethane.
19. 19. A method for manufacturing an optical element, the method comprising: manufacturing a first production mould part according to a method according to any one of the preceding claims, wherein the amount of master substance deposited is in accordance with a first sub-set of the dataset, the first production mould comprising a first cavity; providing a product substance in the first cavity; allowing the product substance to settle thus forming the optical element; and removing the first production mould part from the optical element.
20. 20. The method according to claim 19, further comprising: manufacturing a second production mould part according to a method according to any one of the preceding claims, wherein the amount of master substance deposited is in accordance with a second subset of the dataset, the second sub-set being complementary to the first sub-set; combining the first production mould with the second production mould, such that cavities of the first production mould and the second production mould face one another, thus forming a product cavity; and providing a product substance in the product cavity, the product cavity having a shape equivalent to that of the optical element.

Description

Title: Method of manufacturing a copy mould for an optical element TECHNICAL FIELD The various aspects and implementations thereof relate to manufacturing of optical elements and moulds for casting such optical elements. BACKGROUND Various methods of manufacturing optical elements and moulds are known. It is important that any master object that may serve to manufacture the actual product is of good and robust quality, such that it may be stored for a longer time, without any major risk of deterioration. SUMMARY Certain materials providing master data for casting of optical elements such as lenses, like moulds or positive master shapes that may be provided by means of three-dimensional printing, may deteriorate under the influence of ambient atmosphere. Such deterioration may be drying out thus becoming brittle, deformation, or other, under the influence of temperature and/or a particular humidity level. Alternatively or additionally, such deterioration may be scratching. It is preferred to provide a method of manufacturing of moulds for production of optical elements that addresses these issue. Whereas this method is particularly well suited for the manufacturing of optical elements, it may also be used for other objects. A first aspect provides a method of manufacturing a copy mould for an optical element. The method comprises receiving, in a three-dimensional printing system, a dataset providing a three-dimensional representation of the optical element, depositing on a substrate, by the three-dimensional printing system, an amount of master substance to provide a master piece in accordance with at least part of the dataset and providing, on the substrate, a master formwork around the master piece. In the master formwork, a first amount of mould substance is provided to settle, thus forming a master mould comprising a master cavity that is at least partially defined by the master piece. The master piece is separated from the master mould and a master copy material is cast in the master cavity of the master mould to provide a master copy that is allowed to settle. The master copy is removed from the master mould and a copy formwork is provided around the master copy. A second amount of mould substance is provided in the copy form work that is allowed to settle, thus forming a copy mould comprising a copy cavity, the copy cavity being at least partially defined by the master copy. Firstly, this allows the master substance to be optimised for precision deposition, for example by means of three-dimensional digital printing. This requirement may not always be compatible with long shelf life of a master object. And this method allows for optimisation of the substance used for the master copy for shelflife - and precision casting. Second, this method allows for quick reuse of the substrate. The substrate may be a precision instrument, with very well-defined dimensions and, optionally, well defined alignment markers at very well-defined positions, with tolerances in the orders of micrometres or less. Such substrate is difficult to manufacture, with expensive equipment. Hence, such substrates are expensive. Reuse of the substrates for printing further master pieces is thus preferred, with a short turnaround time. Third, moulds may wear while being used. Casting a mould from master material may result in wear of the master substance, as this may not be optimised for casting of the mould. The substance for the master copy may be chosen differently and harder materials are available for casting, rather than for three-dimensional printing. From a proper master copy, many moulds may be manufactured, providing a virtually endless supply of copy moulds with copy cavities. It is noted that some deformation may occur during the method, depending on process parameters. With sufficient knowledge of such deformations, the deformations may be parametrised or otherwise calculated. These determined calculations may be used for transformation of the data in the dataset used to manufacture the master piece, such that the element used by casting material in the copy mould is a correct representation of the element represented by the dataset. An implementation of the first aspect further comprises, prior to providing a first amount of mould substance, applying an alignment module to the substrate. The alignment modules may be used as a marker providing an indication of the master piece relative to the substrate. This may be used at a later stage, for example for aligning multiple mould pieces. In such scenario, the alignment data provided by the alignment module may be transferred to the copy moulds, via the master copy. Another implementation further comprises providing, by means of at least part of the alignment module, at least one master alignment marker to the master copy. This allows for transfer of alignment data to the copy moulds for aligning copy moulds for manufacturing of the optical element. A further implementatio