WO2014038939A2 - Method for manufacturing a semimanufacture intended for forming an ophthalmic device - Google Patents
Method for manufacturing a semimanufacture intended for forming an ophthalmic device Download PDFInfo
- Publication number
- WO2014038939A2 WO2014038939A2 PCT/NL2013/050643 NL2013050643W WO2014038939A2 WO 2014038939 A2 WO2014038939 A2 WO 2014038939A2 NL 2013050643 W NL2013050643 W NL 2013050643W WO 2014038939 A2 WO2014038939 A2 WO 2014038939A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- lens
- cup
- assembly
- semimanufacture
- optical
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 66
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 36
- 230000003287 optical effect Effects 0.000 claims abstract description 73
- 239000000178 monomer Substances 0.000 claims abstract description 11
- 239000000463 material Substances 0.000 claims abstract description 10
- 230000001681 protective effect Effects 0.000 claims description 26
- 238000009832 plasma treatment Methods 0.000 claims description 11
- 238000001746 injection moulding Methods 0.000 claims description 6
- 238000007730 finishing process Methods 0.000 claims description 4
- 239000011888 foil Substances 0.000 claims description 4
- 230000003746 surface roughness Effects 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 2
- 238000002347 injection Methods 0.000 abstract 1
- 239000007924 injection Substances 0.000 abstract 1
- 238000000465 moulding Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000009966 trimming Methods 0.000 description 3
- 230000003442 weekly effect Effects 0.000 description 3
- 238000000926 separation method Methods 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000000887 hydrating effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00932—Combined cutting and grinding thereof
- B29D11/00942—Combined cutting and grinding thereof where the lens material is mounted in a support for mounting onto a cutting device, e.g. a lathe, and where the support is of machinable material, e.g. plastics
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00009—Production of simple or compound lenses
- B29D11/00038—Production of contact lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00009—Production of simple or compound lenses
- B29D11/0048—Moulds for lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/02—Artificial eyes from organic plastic material
- B29D11/023—Implants for natural eyes
Definitions
- the invention relates to a method for manufacturing a
- the invention also relates to a method for manufacturing a contact lens or an intraocular lens.
- the starting material is a lens blank of which a first side is worked using a turning operation, and of which, thereafter, a second side is worked using a turning operation to obtain two optically accurately defined surfaces. It is precisely for these quality lenses that the turning operation is not simple. Often, it concerns aspherical, non-rotation symmetrical surfaces that are to be manufactured with the turning operation.
- the position of the cutter of the turning lathe should therefore, within a revolution of the holding head of the lathe, follow a defined reciprocating path often in the Z direction (perpendicular to the main rotation axis) of the lathe, so that eventually the aspherical, non-rotation symmetrical surface is formed.
- the resulting lens can for instance be toric, bifocal or have a like optical property.
- the invention contemplates the provision of a new method for manufacturing ophthalmic devices, more particularly for manufacturing intraocular lenses and contact lenses without the above-described
- the invention provides a method for manufacturing a semimanufacture intended for forming an ophthalmic device, more
- an intraocular lens or a contact lens comprising:
- the exposed side of the lens blank can be provided by means of a turning operation with an optically accurately defined surface having the desired properties.
- these desired properties will be customer-specific and depend on the ocular defect of a specific patient.
- the method according to the invention is of particular advantage. Indeed, the specific corrections that are necessary for the specific ocular defects can be created with the turning operation on the second, opposite surface.
- a method for manufacturing a contact lens or an intraocular lens comprising:
- the concave side thereof often has a standard base curve radius, mostly in the range of 8-10 mm, for example, 8.3 mm.
- the optically accurately defined surface of the optical cup part can for instance provide such a base curve radius.
- the optical cup part will be formed by the cup top part.
- the desired optical properties are provided to the contact lens by working the convex side of the lens during the turning operation.
- intraocular lenses these have two opposite convex sides. For obtaining the desired optical properties of the intraocular lens it is sufficient for one of the sides to undergo a turning operation to form an aspherical, non-rotation symmetrical surface.
- the other convex side can have a simple standard contour, such as, for example, a spherical contour. Such a simple standard contour which does not require any further final processing can be eminently provided during a cast molding of the lens blank.
- both the cup top part and the cup bottom part can serve as the optical cup part.
- contact lenses and intraocular lenses having a particular aspherical, non-rotation symmetrical surface can be provided in half the normal turning operation time, since only one of the sides needs to be subjected to a turning operation.
- the machine park in the production facility can therefore, without any extra investment, generate twice as large an output when, instead of very simple prior art lens blanks produced by sawing from a rod of optical material and known in the art by the term "buttons", the semimanufacture obtained using the present method is purchased. It will be clear that this of particular interest from a commercial viewpoint. Moreover, from a technical viewpoint no concessions are made, because the lenses, owing to the presence of the turning operation, can still have any desired optical property. Thus, in this way customized lenses can be provided at considerably lower cost.
- the invention further relates to a semimanufacture assembly obtained with the method according to any one of claims 1-8, to a lens obtained with the method according to claim 11 or 15, and to a packaged lens obtained with the method according to claim 16.
- Fig. 1 shows an exemplary embodiment of a cast mold in perspective exploded view
- Fig. 2 shows a perspective view of the exemplary embodiment of Fig. 1;
- Fig. 3 shows a cross sectional view of a cup top part with lens blank
- Figs. 4-13 show an example of successive production stages for manufacturing a lens.
- Figs. 1 and 2 show in perspective a cup bottom part 12 and a cup top part.
- the topmost part 32 is an optional foil 32 which upon completion of the method that will be described below can be fastened wholly onto the cup bottom part 12 when a finished lens 10 has been placed in the latter, such that a packaged lens is obtained.
- This packaging possibility is only an option and does not constitute the core of the invention.
- the cup top part carries a lens blank 18.
- the lens blank 18 in Fig. 2 has just been formed by cast molding and is yet to undergo a follow-on operation, viz., a turning operation, to form a second optically accurately defined surface.
- the lens blank 18 is bounded by an upstanding edge 28.
- This upstanding edge 28 is part of an embodiment.
- the cup top part with the lens blank 18 situated thereon is shown in cross section in Fig. 3. There, the optional upstanding edge 28 is also clearly visible.
- a method for manufacturing a semimanufacture 20 intended for manufacturing therefrom an ophthalmic device, more particularly an intraocular lens or a contact lens 10.
- the method comprises the following steps:
- a next step of the method comprises:
- finished contact lenses are manufactured which are not bonded to one of the two mold halves 12. Owing to the lens blank 18 according to the invention being bonded to the optical cup part, it can be simply handled and undergo a follow-on operation, such as, for example, a turning operation.
- the figures show an example of the method in which the semimanufacture 20 serves as a starting point for the manufacture of a contact lens 10.
- the optical cup part in that case is formed by the cup top part.
- the side to be worked by a turning operation in a later stage is the convex side of the lens blank 18.
- the concave side is bonded to the cup top part which forms the optical cup part.
- a semimanufacture assembly that is formed can serve as a starting point for the manufacture of an intraocular lens.
- a semimanufacture assembly that is formed can serve as a starting point for the manufacture of an intraocular lens.
- intraocular lens has two convex sides.
- the optical cup part to which the lens blank is bonded can in that case be formed by the cup top part but also by the cup bottom part.
- the method can comprise subjecting the optically accurately defined surface 16 of the optical cup part to a plasma treatment, this plasma treatment taking place before placing the optical cup part on the other cup part 12.
- This plasma treatment should be such as to provide a surface structure which promotes bonding between the lens blank 18 and the optical cup part.
- subjecting a cup part to a plasma treatment is known from US-4,584,148. There, however, the plasma treatment serves to improve the hydrophilicity or wettability of the mold cavity.
- the use of a plasma treatment to form a surface structure that promotes bonding between the lens blank and the optical cup part is not known from that publication.
- the method may be further characterized in that the plasma treatment is a corona plasma treatment.
- the surface structure can comprise a particular surface roughness of such a fineness that it does not visibly influence the optical properties of the lens blank 18 which is
- the lens blank 18 then does not need to undergo any further
- the surface structures that form the surface roughness can be smaller than the wavelength of the visible hght.
- a lens blank 18 is obtained in which incidental light is not influenced by those copied surface structures in a visible manner.
- a protective cap 22 may be placed on the assembly of the lens blank 18 and the optical cup part to form the semimanufacture assembly 20 which comprises at least the optical cup part, a lens blank 18 and the protective cap 22. This action is shown in Fig. 6 and the assembly thereby obtained is shown in Fig. 7.
- the semimanufacture assembly 20 with or without protective cap 22 - is a product marketable in itself, which can be supplied to lens
- Such semimanufacture assemblies 20 could be supplied, for instance, by the same firms that presently supply optical material in the form of flat cylindrical lens blanks to lens manufacturers. Thus, in a simple manner they enable the lens manufacturers that have a series of lathes at their disposal to nearly double their manufacturing output without their needing to expand the number of lathes.
- the optional protective cap 22 facilitates handling of the optical cup part and the lens blank 18 bonded thereto. Moreover, when use is made of such a protective cap 22, there is less chance of damage of the lens blank 18, and the lens 10 to be formed therefrom, during transport of the assembly. Such transport can take place, for instance, from the semimanufacture supplier to the lens manufacturer.
- the semimanufacture assembly 20 can then be taken out of the package and be mounted on a kind of handling cap 24, for example, with a kind of bayonet connection which, for instance, engages the positioning means of the cup part.
- Such positioning means can comprise, for example, a number of radially extending legs which are connected to a circumferential edge of the cup part.
- the cup part is provided with three of such radially extending legs.
- the handling cap may be situated, for instance, on the side of the cup part remote from the lens blank 18.
- This handling cap can be simply placed in a holding head 24 of a lathe or be an integral part thereof.
- the handling cap is an integral part of the holding head 24 of the lathe.
- the handling cap, or the holding head 24 when the handling cap is an integral part of the holding head 24 is provided with a reference stop 36.
- the optical cup part may then be further provided with a reference lug 34.
- the reference lug 34 is moved against the reference stop 36, so that the rotational position of the cup part relative to the holding head 24 is accurately determined. In that manner, the rotational position of the lens blank 18 in the lathe is accurately determined.
- the optically accurately defined surface yet to be formed in the lathe can then be accurately oriented, also in a rotational sense, relative to the optically accurately defined surface already formed upon curing, which can be, for example, aspherical.
- the finished lens 10 can be removed from the cup part and be accommodated in a definitive package, whether or not in a moist environment.
- a subsequent step that is to be performed is to make from the lens blank 18 with a turning operation a full lens 10 with two optically accurately defined surfaces. Because during the turning operation the bond between the lens blank 18 and the optical cup part is subject to shear, it is favorable, in a further elaboration of the invention, when the optical cup part is provided with an upstanding edge 28 which forms a boundary for the monomeric material, so that, after curing of the monomeric material, the boundary determines a circumferential edge 11 of the lens blank 18. Such an edge provides an enlarged bonding surface between the lens blank 18 and the optical cup part. This leads to a better bonding between the two parts.
- a still better shear resistance of the lens blank 18 of the optical cup part can be obtained, according to a further elaboration, when the upstanding edge 28, seen in top plan view, has a contour deviating from a circle, for instance, an elliptical contour.
- the upstanding edge 28 seen in top plan view, has a contour deviating from a circle, for instance, an elliptical contour.
- Such an effect can also be achieved with a circular edge 28 having a flattened portion or with an upstanding edge 28 polygonal in top plan view.
- the following is about a method for manufacturing a contact lens or an intraocular lens 10, of which an example will be described with reference to Figs. 7-13. The method comprises:
- Fig. 7 This step is shown in Fig. 7.
- the exemplary embodiment shown relates to a semimanufacture assembly which is provided with a protective cap 22.
- the protective cap 22 is only optional and the invention is not limited to such an embodiment.
- the method comprises the following step:
- the assembly 30 of the optical cup part and the lens 10 can be removed from the holding head 24 of the lathe. This step is shown in Fig. 11.
- the lens 10 can be separated from the optical cup part so as to obtain a loose lens 10.
- a separation can be simply realized by hydrating the lens 10 in a manner known per se with demineralized water or with a saline solution. The lens 10 then swells, becomes supple and comes off the optical cup part.
- the protective cap 22 simplifies the handling of the optical cup part and, bonded thereto, the lens blank 18 and in a later stage lens 10, and reduces the risk of damage of the lens blank 18 and the lens 10.
- the method comprises removing the protective cap 22 after the semimanufacture assembly 20 has been placed in the holding head 24 and prior to the turning operation to form the lens 10.
- the protective cap 22 can be re-placed to provide for easy handling and to minimize the risk of damage of the lens 10.
- the assembly 30 of the optical cup part, the lens 10 and the protective cap 22 can be simply taken from the holding head 24.
- the protective cap 22 can be removed from the optical cup part and the lens 10. This will generally be done at a different place in the factory. The assembly 30 must therefore be transported and then the presence of the protective cap 22 is of benefit.
- the lens 10 and the optical cup part can be separated in the manner described above so as to obtain a loose lens 10.
- the loose lens 10 can be packaged with addition of fluid, for instance in the cup bottom part 12, the cup bottom part 12 then being sealed with a foil 32.
- the cup bottom part 12 with the foil 32 then forms a liquid-tight package for the lens 10 and can be offered so to the end consumer.
- the invention also relates to a semimanufacture assembly 20 obtained with the method according to any one of claims 1-8, a lens 10 obtained with the method according to claim 11 or 15, and a packaged lens 10 obtained with the method according to claim 16.
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- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Ophthalmology & Optometry (AREA)
- Mechanical Engineering (AREA)
- Prostheses (AREA)
- Eyeglasses (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
A method for manufacturing a semimanufacture intended for manufacturing therefrom an intraocular lens or a contact lens, wherein a cup bottom part and a cup top part are injection molded, at least one of the two cup parts being an optical cup part which is provided with an optically accurately defined surface, wherein monomer is injected into the cup bottom part, and the cup top part is placed on the cup bottom part so as to form a cast mold filled with monomeric material. Next, the monomer in the cast mold is cured to form a lens blank, and the cup top part and the cup bottom part are separated from each other for exposing the formed lens blank, which is bonded to the optical cup part during curing, to provide a semimanufacture assembly, to be worked with a lathe, which comprises the optical cup part and the lens blank. Then, the lens blank can undergo a turning operation to form a lens having two optically accurately defined surfaces.
Description
Title: Method for manufacturing a semimanufacture intended for forming an ophthalmic device
FIELD
The invention relates to a method for manufacturing a
semimanufacture intended for forming an ophthalmic device, more
particularly an intraocular lens or a contact lens. The invention also relates to a method for manufacturing a contact lens or an intraocular lens.
BACKGROUND
In practice, high-quality contact lenses that are worn for a prolonged time, for example, three months, are not made with a cast mold process, unlike daily, weekly and monthly lenses. A method for manufacturing daily, weekly and monthly lenses is described in US-4,647,261. There, use is made of a cast mold process to form a contact lens whereby both accurately defined surfaces are formed during the cast mold process. Since in this known method for manufacturing a lens, flashes may have been formed on the circumferential edge of the lens, the circumferential edge of the lens still needs to undergo a finishing process referred to as trimming. Such trimming is a kind of turning operation that takes place while the lens, already optically finished, is still secured to one of the cast mold halves. After trimming, possibly a buffing operation is necessary.
High-quality contact lenses, however, have hitherto, in practice, not been manufactured with cast molding. For such high-grade contact lenses, the starting material is a lens blank of which a first side is worked using a turning operation, and of which, thereafter, a second side is worked using a turning operation to obtain two optically accurately defined surfaces. It is precisely for these quality lenses that the turning operation is not simple. Often, it concerns aspherical, non-rotation symmetrical surfaces that are to be manufactured with the turning operation. The position of the cutter of the turning lathe should
therefore, within a revolution of the holding head of the lathe, follow a defined reciprocating path often in the Z direction (perpendicular to the main rotation axis) of the lathe, so that eventually the aspherical, non-rotation symmetrical surface is formed. The resulting lens can for instance be toric, bifocal or have a like optical property.
For intraocular lenses, too, it holds that they have hitherto been manufactured in practice by starting from a lens blank in the form of a flat, circular disc which is then worked on both sides by a turning operation to form two optically accurately defined surfaces.
Such a method of manufacture is costly and time-consuming. Placing the lens blank in a lathe is to be carried out twice and, in view of the accuracy, requires much skill. Moreover, the time the turning operation takes per lens is rather high. That is why a production facility for such contact lenses often has a large number of lathes. In view of the high accuracy and the complicated control that such lathes should have, setting up such production facilities entails a huge investment. As, moreover, the processing duration per lens is also rather high, the cost price of such quality contact lenses and intraocular lenses is relatively high. SUMMARY
The invention contemplates the provision of a new method for manufacturing ophthalmic devices, more particularly for manufacturing intraocular lenses and contact lenses without the above-described
disadvantages.
To that end, the invention provides a method for manufacturing a semimanufacture intended for forming an ophthalmic device, more
particularly an intraocular lens or a contact lens, comprising:
• manufacturing a cup bottom part by injection molding;
• manufacturing a cup top part by injection molding, at least one of the two cup parts being an optical cup part which is provided with an optically accurately defined surface;
• injecting monomer into the cup bottom part and placing the cup top part on the cup bottom part to form a cast mold filled with monomeric material;
• curing the monomer in the cast mold to form a lens blank; and
• separating the cup top part and the cup bottom part for exposing the formed lens blank, which is bonded to the optical cup part during curing, to provide a semimanufacture assembly, to be worked with a turning lathe, which comprises the optical cup part and the lens blank, the lens blank comprising an optically accurately formed surface which is bonded to the optical cup part and an opposite surface which is to undergo a finishing process in a turning lathe to form an optically accurately defined surface.
Starting from such a semimanufacture assembly, subsequently, in a production facility as described above, with the aid of a lathe the exposed side of the lens blank can be provided by means of a turning operation with an optically accurately defined surface having the desired properties. Typically, these desired properties will be customer-specific and depend on the ocular defect of a specific patient. Precisely for manufacturing lenses for the benefit of patients with complex ocular defects where no use can be made of daily, weekly or monthly lenses, the method according to the invention is of particular advantage. Indeed, the specific corrections that are necessary for the specific ocular defects can be created with the turning operation on the second, opposite surface.
According to the invention, to that end, a method for manufacturing a contact lens or an intraocular lens is provided, comprising:
• carrying out the method for providing the semimanufacture assembly as described above;
placing the semimanufacture assembly in the holding head of a turning lathe, the lens blank being on the side of the optical cup part remote from the holding head so as to be accessible to a cutter of the lathe; subjecting the lens blank to a turning operation with the cutter to form a lens having on both sides an optically accurately defined surface, wherein one optically accurately defined surface is formed during curing of the monomer in the cast mold and wherein the second optically accurately defined surface is formed during the turning operation.
As regards contact lenses, the concave side thereof often has a standard base curve radius, mostly in the range of 8-10 mm, for example, 8.3 mm. The optically accurately defined surface of the optical cup part can for instance provide such a base curve radius. In the manufacture of contact lenses the optical cup part will be formed by the cup top part. The desired optical properties are provided to the contact lens by working the convex side of the lens during the turning operation.
As regards intraocular lenses, these have two opposite convex sides. For obtaining the desired optical properties of the intraocular lens it is sufficient for one of the sides to undergo a turning operation to form an aspherical, non-rotation symmetrical surface. The other convex side can have a simple standard contour, such as, for example, a spherical contour. Such a simple standard contour which does not require any further final processing can be eminently provided during a cast molding of the lens blank. For intraocular lenses, both the cup top part and the cup bottom part can serve as the optical cup part.
Thus, therefore, contact lenses and intraocular lenses having a particular aspherical, non-rotation symmetrical surface can be provided in half the normal turning operation time, since only one of the sides needs to be subjected to a turning operation. The machine park in the production facility
can therefore, without any extra investment, generate twice as large an output when, instead of very simple prior art lens blanks produced by sawing from a rod of optical material and known in the art by the term "buttons", the semimanufacture obtained using the present method is purchased. It will be clear that this of particular interest from a commercial viewpoint. Moreover, from a technical viewpoint no concessions are made, because the lenses, owing to the presence of the turning operation, can still have any desired optical property. Thus, in this way customized lenses can be provided at considerably lower cost.
The invention further relates to a semimanufacture assembly obtained with the method according to any one of claims 1-8, to a lens obtained with the method according to claim 11 or 15, and to a packaged lens obtained with the method according to claim 16. BRIEF DESCRIPTION OF THE FIGURES
Fig. 1 shows an exemplary embodiment of a cast mold in perspective exploded view;
Fig. 2 shows a perspective view of the exemplary embodiment of Fig. 1;
Fig. 3 shows a cross sectional view of a cup top part with lens blank;
Figs. 4-13 show an example of successive production stages for manufacturing a lens.
DETAILED DESCRIPTION
Figs. 1 and 2 show in perspective a cup bottom part 12 and a cup top part. The topmost part 32 is an optional foil 32 which upon completion of the method that will be described below can be fastened wholly onto the cup bottom part 12 when a finished lens 10 has been placed in the latter, such that a packaged lens is obtained. This packaging possibility, however, is only an option and does not constitute the core of the invention. In Fig. 2 it can be seen
that the cup top part carries a lens blank 18. The lens blank 18 in Fig. 2 has just been formed by cast molding and is yet to undergo a follow-on operation, viz., a turning operation, to form a second optically accurately defined surface. Also, it is visible in Fig. 2 that the lens blank 18 is bounded by an upstanding edge 28. This upstanding edge 28 is part of an embodiment. The cup top part with the lens blank 18 situated thereon is shown in cross section in Fig. 3. There, the optional upstanding edge 28 is also clearly visible.
The method will be further elucidated below with reference to Figs. 4-13, in which an exemplary embodiment is shown.
In the most general terms, a method is provided for manufacturing a semimanufacture 20 intended for manufacturing therefrom an ophthalmic device, more particularly an intraocular lens or a contact lens 10. The method comprises the following steps:
• manufacturing a cup bottom part 12 by injection molding;
• manufacturing a cup top part by injection molding, at least one of the two cup parts 12, 14 being an optical cup part which is provided with an optically accurately defined surface 16;
• injecting monomer into the cup bottom part 12 and placing the cup top part on the cup bottom part 12 to form a cast mold 12, 14 filled with monomeric material;
• curing the monomer in the cast mold 12,14 to form a lens blank 18.
When these steps have been traversed, one has available a cast mold 12, 14 having therein a lens blank 18, of which an example is shown in Fig. 4. A next step of the method comprises:
• separating the cup top part and the cup bottom part 12 for exposing the formed lens blank 18, which is bonded to the optical cup part during curing, to provide a semimanufacture assembly 20, to be worked with a turning lathe, which comprises the optical cup part and the lens blank 18, the lens blank 18 comprising an optically accurately defined surface which is bonded to the optical cup part and an opposite
surface which is to undergo a finishing process in a turning lathe to form an optically accurately defined surface.
In the method of cast molding known hitherto, finished contact lenses are manufactured which are not bonded to one of the two mold halves 12. Owing to the lens blank 18 according to the invention being bonded to the optical cup part, it can be simply handled and undergo a follow-on operation, such as, for example, a turning operation. The figures show an example of the method in which the semimanufacture 20 serves as a starting point for the manufacture of a contact lens 10. The optical cup part in that case is formed by the cup top part. The side to be worked by a turning operation in a later stage is the convex side of the lens blank 18. The concave side is bonded to the cup top part which forms the optical cup part.
In an alternative example of the method, which is not represented in the figures, a semimanufacture assembly that is formed can serve as a starting point for the manufacture of an intraocular lens. In general, such an
intraocular lens has two convex sides. The optical cup part to which the lens blank is bonded can in that case be formed by the cup top part but also by the cup bottom part.
In an embodiment, the method can comprise subjecting the optically accurately defined surface 16 of the optical cup part to a plasma treatment, this plasma treatment taking place before placing the optical cup part on the other cup part 12. This plasma treatment should be such as to provide a surface structure which promotes bonding between the lens blank 18 and the optical cup part. In itself, subjecting a cup part to a plasma treatment is known from US-4,584,148. There, however, the plasma treatment serves to improve the hydrophilicity or wettability of the mold cavity. The use of a plasma treatment to form a surface structure that promotes bonding between the lens blank and the optical cup part is not known from that publication.
In an embodiment, the method may be further characterized in that the plasma treatment is a corona plasma treatment.
In a further elaboration of the method, the surface structure can comprise a particular surface roughness of such a fineness that it does not visibly influence the optical properties of the lens blank 18 which is
manufactured with the method.
The lens blank 18 then does not need to undergo any further
processing on the side that is formed in contact with the optical surface 16 of the optical cup part.
In an embodiment the surface structures that form the surface roughness can be smaller than the wavelength of the visible hght. When such surface structures are copied into the lens blank 18 during cast molding, a lens blank 18 is obtained in which incidental light is not influenced by those copied surface structures in a visible manner.
In an exemplary embodiment, of which an example is shown in
Figs. 4-13, a protective cap 22 may be placed on the assembly of the lens blank 18 and the optical cup part to form the semimanufacture assembly 20 which comprises at least the optical cup part, a lens blank 18 and the protective cap 22. This action is shown in Fig. 6 and the assembly thereby obtained is shown in Fig. 7.
The semimanufacture assembly 20 with or without protective cap 22 - is a product marketable in itself, which can be supplied to lens
manufacturers. Such semimanufacture assemblies 20 could be supplied, for instance, by the same firms that presently supply optical material in the form of flat cylindrical lens blanks to lens manufacturers. Thus, in a simple manner they enable the lens manufacturers that have a series of lathes at their disposal to nearly double their manufacturing output without their needing to expand the number of lathes.
The optional protective cap 22 facilitates handling of the optical cup part and the lens blank 18 bonded thereto. Moreover, when use is made of such a protective cap 22, there is less chance of damage of the lens blank 18, and the lens 10 to be formed therefrom, during transport of the assembly. Such
transport can take place, for instance, from the semimanufacture supplier to the lens manufacturer.
In an alternative further elaboration, the manufacturer of the semimanufacture assembly 20, instead of fitting a protective cap 22 onto it, can package it in a package, for example, a blister package. From a cost perspective, that is cheaper than co-supplying a protective cap 22. Moreover, such a blister package provides the advantage that the lens blank 18 is well protected from moisture and oxygen and other external influences. At the lens manufacturer's, the semimanufacture assembly 20 can then be taken out of the package and be mounted on a kind of handling cap 24, for example, with a kind of bayonet connection which, for instance, engages the positioning means of the cup part. Such positioning means can comprise, for example, a number of radially extending legs which are connected to a circumferential edge of the cup part. In the figures, the cup part is provided with three of such radially extending legs. The handling cap may be situated, for instance, on the side of the cup part remote from the lens blank 18. This handling cap can be simply placed in a holding head 24 of a lathe or be an integral part thereof. In the exemplary embodiment represented in the figures, the handling cap is an integral part of the holding head 24 of the lathe. However, when the handling cap is not an integral part of the holding head of the lathe but is to be received in it, then, according to an exemplary embodiment, it may be advantageous when the handling cap and the holding head 24 are each provided with reference surfaces that adjoin each other, so that the rotational position of the handling cap in the holding head 24 is accurately defined. This can be of importance when the optically accurately defined surface formed during curing is not spherical but aspherical, such as, for example, toric, cylindrical or bifocal. In that case it is preferred that the handling cap, or the holding head 24 when the handling cap is an integral part of the holding head 24, is provided with a reference stop 36. The optical cup part may then be further provided with a reference lug 34. Upon placement of the cup part in the
handling cap, which is an integral part of the holding head 24 in the figures, the reference lug 34 is moved against the reference stop 36, so that the rotational position of the cup part relative to the holding head 24 is accurately determined. In that manner, the rotational position of the lens blank 18 in the lathe is accurately determined. The optically accurately defined surface yet to be formed in the lathe can then be accurately oriented, also in a rotational sense, relative to the optically accurately defined surface already formed upon curing, which can be, for example, aspherical. Upon completion of the turning operation, the finished lens 10 can be removed from the cup part and be accommodated in a definitive package, whether or not in a moist environment.
As has already become clear from the foregoing, a subsequent step that is to be performed is to make from the lens blank 18 with a turning operation a full lens 10 with two optically accurately defined surfaces. Because during the turning operation the bond between the lens blank 18 and the optical cup part is subject to shear, it is favorable, in a further elaboration of the invention, when the optical cup part is provided with an upstanding edge 28 which forms a boundary for the monomeric material, so that, after curing of the monomeric material, the boundary determines a circumferential edge 11 of the lens blank 18. Such an edge provides an enlarged bonding surface between the lens blank 18 and the optical cup part. This leads to a better bonding between the two parts.
A still better shear resistance of the lens blank 18 of the optical cup part can be obtained, according to a further elaboration, when the upstanding edge 28, seen in top plan view, has a contour deviating from a circle, for instance, an elliptical contour. In that case, there is not only a force-closed connection but also a form -closed connection between the lens blank 18 and the optical cup part, since rotation of the elliptical lens blank 18 within the elliptical upstanding edge 28 is not possible. Such an effect can also be achieved with a circular edge 28 having a flattened portion or with an upstanding edge 28 polygonal in top plan view.
The following is about a method for manufacturing a contact lens or an intraocular lens 10, of which an example will be described with reference to Figs. 7-13. The method comprises:
• carrying out the method as described above for providing the
semimanufacture assembly 20; and
• placing the semimanufacture assembly 20 in the holding head 24 of a lathe, the lens blank 18 being situated on the side of the optical cup part remote from the holding head 24, so as to be accessible to a cutter 26 of the lathe for forming the second optically accurately defined surface.
This step is shown in Fig. 7. The exemplary embodiment shown relates to a semimanufacture assembly which is provided with a protective cap 22. As already indicated before, the protective cap 22 is only optional and the invention is not limited to such an embodiment. Next, the method comprises the following step:
• subjecting the lens blank 18 to a turning operation with the cutter 26 to form a lens 10 having on both sides an optically accurately defined surface, wherein one optically accurately defined surface is formed during curing of the monomer in the cast mold 12, 14 and wherein the second optically accurately defined surface is formed during the turning operation.
This step is represented in Fig. 9. Thus, therefore, an assembly 30 is obtained which comprises a finished lens 10 which is still bonded to the optical cup part.
In an embodiment of the method, thereupon, after the turning operation, the assembly 30 of the optical cup part and the lens 10 can be removed from the holding head 24 of the lathe. This step is shown in Fig. 11.
After this, according to a further elaboration of the invention, the lens 10 can be separated from the optical cup part so as to obtain a loose lens 10. Such a separation can be simply realized by hydrating the lens 10 in a manner
known per se with demineralized water or with a saline solution. The lens 10 then swells, becomes supple and comes off the optical cup part.
It is practical for the separation of the lens 10 from the optical cup part to be carried out after the assembly 30 of the optical cup part and the lens 10 has been removed from the holding head 24 of the lathe.
As already described above, use of the protective cap 22 as shown in Figs. 3-13 is an option and not a necessity. The protective cap 22 simplifies the handling of the optical cup part and, bonded thereto, the lens blank 18 and in a later stage lens 10, and reduces the risk of damage of the lens blank 18 and the lens 10.
When use is made of such a protective cap 22, then, according to a further elaboration of the invention, mounting the semimanufacture assembly 20 in the holding head 24 takes place while the protective cap 22 is still on the lens blank 18 and the optical cup part. Next, the method comprises removing the protective cap 22 after the semimanufacture assembly 20 has been placed in the holding head 24 and prior to the turning operation to form the lens 10. When the turning operation has been completed, the protective cap 22 can be re-placed to provide for easy handling and to minimize the risk of damage of the lens 10. After this, the assembly 30 of the optical cup part, the lens 10 and the protective cap 22 can be simply taken from the holding head 24.
In further method steps the protective cap 22 can be removed from the optical cup part and the lens 10. This will generally be done at a different place in the factory. The assembly 30 must therefore be transported and then the presence of the protective cap 22 is of benefit.
Next, the lens 10 and the optical cup part can be separated in the manner described above so as to obtain a loose lens 10.
In a further elaboration, the loose lens 10 can be packaged with addition of fluid, for instance in the cup bottom part 12, the cup bottom part 12 then being sealed with a foil 32. The cup bottom part 12 with the foil 32 then
forms a liquid-tight package for the lens 10 and can be offered so to the end consumer.
The invention also relates to a semimanufacture assembly 20 obtained with the method according to any one of claims 1-8, a lens 10 obtained with the method according to claim 11 or 15, and a packaged lens 10 obtained with the method according to claim 16.
While the invention has been represented in detail and described with reference to the drawing, this drawing and this description should be regarded as an example only. The invention is not limited to the embodiment described. Features that are described in preceding claims can be combined with each other. The reference numerals in the claims should not be construed as limitations of the claims but serve for clarification only. Different variants are possible.
Claims
1. A method for manufacturing a semimanufacture intended for
manufacturing therefrom an ophthalmic device, more particularly an intraocular lens or a contact lens (10), comprising:
• manufacturing a cup bottom part (12) by injection molding;
· manufacturing a cup top part (14) by injection molding, at least one of the two cup parts (12,14) being an optical cup part which is provided with an optically accurately defined surface (16);
• injecting monomer into the cup bottom part (12) and placing the cup top part (14) on the cup bottom part (12) to form a cast mold (12,14) filled with monomeric material;
• curing the monomer in the cast mold (12,14) to form a lens blank (18); and
• separating the cup top part (14) and the cup bottom part (12) for
exposing the formed lens blank (18), which is bonded to the optical cup part during curing, to provide a semimanufacture assembly (20), to be worked with a turning lathe, which comprises the optical cup part and the lens blank (18), the lens blank (18) comprising an optically accurately defined surface which is bonded to the optical cup part and an opposite surface which is to undergo a finishing process in a turning lathe to form an optically accurately defined surface.
The method according to claim 1, comprising:
subjecting the optically accurately defined surface (16) of the optical cup part to a plasma treatment before placement thereof on the other cup part (12) to form a surface structure which promotes bonding between the lens blank (18) and the optical cup part.
3. The method according to claim 2, wherein the plasma treatment is a corona plasma treatment.
4. The method according to claim 2 or 3, wherein the surface structure comprises a particular surface roughness of such fineness that it does not visibly influence the optical properties of the lens blank (18) which is manufactured with the method.
5. The method according to claim 4, wherein the surface structures that form the surface roughness are smaller than the wavelength of the visible light.
6. The method according to any one of the preceding claims, comprising: • placing a protective cap (22) on the assembly of the lens blank (18) and the optical cup part to form the semimanufacture assembly (20) which comprises at least the optical cup part, a lens blank (18) and the protective cap (22).
7. The method according to any one of the preceding claims, wherein the optical cup part is provided with an upstanding edge (28) which forms a boundary for the monomeric material, so that, after curing of the monomeric material, the boundary defines a circumferential edge (11) of the lens blank (18).
8. The method according to claim 7, wherein the upstanding edge (28), seen in top plan view, has a contour deviating from a circle, for example, an elliptical contour.
9. A method for manufacturing a contact lens or an intraocular lens, comprising:
carrying out the method according to any one of the preceding claims for providing the semimanufacture assembly (20);
placing the semimanufacture assembly (20) in the holding head (24) of a turning lathe, the lens blank (18) being situated on the side of the optical cup part remote from the holding head (24) so as to be accessible to a cutter (26) of the lathe for forming the second optically accurately defined surface;
subjecting the lens blank (18) to a turning operation with the cutter (26) to form a lens (10) having on both sides an optically accurately defined surface, wherein one optically accurately defined surface is formed during curing of the monomer in the cast mold (12, 14) and wherein the second optically accurately defined surface is formed during the turning operation.
The method according to claim 9, comprising:
after the turning operation, removing the assembly (30) of the optical cup part and the lens (10) from the holding head (24) of the lathe.
The method according to claim 9 or 10, comprising:
separating the lens (10) from the optical cup part to obtain
lens (10).
12. The method according to claim 11, wherein separating the lens (10) from the optical cup part is carried out after the assembly (30) of the optical cup part and the lens (10) is removed from the holding head (24) of the lathe.
13. The method according to any one of claims 9-12, wherein the carrying out of the method for providing the semimanufacture assembly (20) is a method according to claim 6 so that the semimanufacture assembly (20) comprises an optical cup part, a lens blank (18) and a protective cap (22),
wherein placing the semimanufacture assembly (20) in the holding head (24) takes place while the protective cap (22) is still on the lens blank (18) and the optical cup part, the method further comprising:
• removing the protective cap (22) after the semimanufacture assembly (20) is placed in the holding head (24) and prior to the turning operation to form the lens (10);
• re-placing the protective cap (22) after the turning operation on the lens blank (18) to form the lens (10);
• taking the assembly (30) of the optical cup part, the lens (10) and the protective cap (22) out of the holding head (24).
14. The method according to claim 13, comprising:
• removing the protective cap (22) from the optical cup part and the
lens (10).
15. The method according to claim 13 or, comprising:
• separating the lens (10) and the optical cup part to obtain a loose
lens (10).
16. The method according to claim 9 or 15, wherein the loose lens (10) is packaged with addition of fluid, for instance in the cup bottom part (12), wherein the cup bottom part (12) is sealed with a foil (32).
17. A semimanufacture assembly (20) obtained with the method according to any one of claims 1-8.
18. A lens (10) obtained with the method according to claim 11 or 15.
19. A packaged lens (10) obtained with the method according to claim 16.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP13767138.4A EP2892711B1 (en) | 2012-09-07 | 2013-09-06 | Method for manufacturing an intraocular lens or a contact lens |
TW102144590A TW201510600A (en) | 2013-09-06 | 2013-12-05 | Method for manufacturing a semimanufacture intended for forming an ophthalmic device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL2009432A NL2009432C2 (en) | 2012-09-07 | 2012-09-07 | METHOD FOR MANUFACTURING A SEMI-MANUFACTURE INTENDED FOR FORMING A SHTHALMIC DEVICE |
NL2009432 | 2012-09-07 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2014038939A2 true WO2014038939A2 (en) | 2014-03-13 |
WO2014038939A3 WO2014038939A3 (en) | 2014-05-30 |
Family
ID=47278950
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NL2013/050643 WO2014038939A2 (en) | 2012-09-07 | 2013-09-06 | Method for manufacturing a semimanufacture intended for forming an ophthalmic device |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2892711B1 (en) |
NL (1) | NL2009432C2 (en) |
WO (1) | WO2014038939A2 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4584148A (en) | 1984-01-30 | 1986-04-22 | International Hydron Corporation | Method for the precision trimming of the edge of a centrifugally cast lens |
US4647261A (en) | 1983-09-19 | 1987-03-03 | International Hydron Corporation | Cutting device and method for the precision trimming of the edge of a cast lens |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1143518A (en) * | 1979-01-15 | 1983-03-29 | George T. Croft | Method and apparatus for making plastic lenses |
US4247492A (en) * | 1979-06-28 | 1981-01-27 | Neefe Optical Laboratory, Inc. | Method of controlling the adhesion of cast lenses to the mold |
AU577315B2 (en) * | 1983-09-27 | 1988-09-22 | Barnes-Hind Inc. | Lens mould and moulding |
US5071101A (en) * | 1990-03-26 | 1991-12-10 | Wood Kenneth E | Mold for an intraocular/contact lens |
DE29608877U1 (en) * | 1996-05-17 | 1996-08-22 | Opto Tech Optikmaschinen GmbH, 35435 Wettenberg | Holder for optical lenses |
-
2012
- 2012-09-07 NL NL2009432A patent/NL2009432C2/en active
-
2013
- 2013-09-06 WO PCT/NL2013/050643 patent/WO2014038939A2/en active Application Filing
- 2013-09-06 EP EP13767138.4A patent/EP2892711B1/en active Active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4647261A (en) | 1983-09-19 | 1987-03-03 | International Hydron Corporation | Cutting device and method for the precision trimming of the edge of a cast lens |
US4584148A (en) | 1984-01-30 | 1986-04-22 | International Hydron Corporation | Method for the precision trimming of the edge of a centrifugally cast lens |
Also Published As
Publication number | Publication date |
---|---|
EP2892711B1 (en) | 2022-11-02 |
WO2014038939A3 (en) | 2014-05-30 |
EP2892711A2 (en) | 2015-07-15 |
NL2009432C2 (en) | 2014-03-10 |
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