Single mould alignment
First Claim
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1. A process for producing a multiplicity of contact lenses from a starting material which can be crosslinked by applying suitable energy, the process comprising the steps of:
- (a) providing a unit having a plurality of individual reusable moulds, wherein each mould has a female mould half, a male mould half, wherein the female and male mould halves, independently of each other, include one or more guide surfaces, wherein the guide surfaces of the female and male mould halves provide centering and adjusting elements which are all necessary for substantially accurate and automatic centering/positioning of the female and male mould halves in relation to each other in each individual reusable mould, without additional adjustment work, when the female and male mould are joined to form a mould cavity defining the shape of a contact lens to be produced;
(b) Metering the starting material into the female mould halves;
(c) Simultaneously closing the individual moulds to join the male mould halves to the female mould halves to form mould cavities containing the starting material and at the same time to individually and automatically perform, by means of the guided surfaces of the female and male mould halves of each individual mould, accurate alignment of the female and male mould halves of each of the individual moulds;
(d) Applying energy to crosslink and/or polymerize the starting material within the mould cavities in order to produce the contact lenses;
(e) Separating the male mould halves from the female mould halves;
(f) Washing the contact lenses to remove uncrosslinked starting material;
(g) Ensuring that the contact lenses are resting on selected mould halves;
(h) Checking whether the contact lenses are free of faults;
(i) Gripping the contact lenses in order to remove the contact lenses from the selected mould halves;
(j) Depositing each fault-free contact lens into a package;
(k) Cleaning and drying the female and the male mould halves;
(l) Bringing the female and male mould halves into a position for metering the starting material; and
(m) cyclically repeating steps (b) to (l).
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Abstract
The invention tackles the problem of improving the production process for contact lenses further, so that the production costs for contact lenses can be reduced further and the production capacities can be increased. To this end, provision is made for the two mould halves, which together form the mould for producing a contact lens, to be fixed to each other and/or detachably connected to each other by means of individual half-mould guide. In conjunction with a cyclic production process, a high degree of automation can be achieved in this way.
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Citations
44 Claims
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1. A process for producing a multiplicity of contact lenses from a starting material which can be crosslinked by applying suitable energy, the process comprising the steps of:
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(a) providing a unit having a plurality of individual reusable moulds, wherein each mould has a female mould half, a male mould half, wherein the female and male mould halves, independently of each other, include one or more guide surfaces, wherein the guide surfaces of the female and male mould halves provide centering and adjusting elements which are all necessary for substantially accurate and automatic centering/positioning of the female and male mould halves in relation to each other in each individual reusable mould, without additional adjustment work, when the female and male mould are joined to form a mould cavity defining the shape of a contact lens to be produced;
(b) Metering the starting material into the female mould halves;
(c) Simultaneously closing the individual moulds to join the male mould halves to the female mould halves to form mould cavities containing the starting material and at the same time to individually and automatically perform, by means of the guided surfaces of the female and male mould halves of each individual mould, accurate alignment of the female and male mould halves of each of the individual moulds;
(d) Applying energy to crosslink and/or polymerize the starting material within the mould cavities in order to produce the contact lenses;
(e) Separating the male mould halves from the female mould halves;
(f) Washing the contact lenses to remove uncrosslinked starting material;
(g) Ensuring that the contact lenses are resting on selected mould halves;
(h) Checking whether the contact lenses are free of faults;
(i) Gripping the contact lenses in order to remove the contact lenses from the selected mould halves;
(j) Depositing each fault-free contact lens into a package;
(k) Cleaning and drying the female and the male mould halves;
(l) Bringing the female and male mould halves into a position for metering the starting material; and
(m) cyclically repeating steps (b) to (l). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
where R is lower alkylene with up to 8 carbon atoms, R1 is hydrogen or lower alkyl and R2 is an olefinically unsaturated, electron-withdrawing copolymerizable radical.
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13. A process according to claim 1, wherein at least visual quality inspection of the contact lenses is provided, the inspection comprising the examination of a central region of each contact lens and of a marginal region of the contact lens for faults.
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14. A process according to claim 1, which comprises centering each contact lens within a female mould half before the contact lens is gripped in order to remove it from the female mould half.
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15. A process according to claim 1, which comprises at least partial drying of each contact lens in order to remove surface water, which could impair the visual inspection of the contact lens.
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16. A process according to claim 13, wherein the visual inspection of the central region of each contact lens is carried out immediately after the energy for crosslinking or polymerization of the starting material has been applied.
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17. A process according to claim 13, wherein the visual inspection of each entire contact lens is carried out in an intermediate container filled with a liquid.
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18. A process according to claim 1, wherein the duration of each process step is less than one minute.
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19. A process according to claim 1, wherein the duration for at least one process step is less than 10 seconds.
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20. A process according to claim 1, wherein the process step of ensuring that the contact lenses are resting on selected mould halves also comprises transferring the contact lenses from the non-selected mould halves to the appropriate selected mould halves.
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21. A process according to claim 20, wherein the selected mould halves are the female mould halves and the non-selected mould halves are the male mould halves.
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22. A process according to claim 1, wherein the mould halves are reused and at least 10,000 contact lenses are produced with them.
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23. A process according to claim 1, wherein the mould halves are reused and at least 500,000 contact lenses are produced with them.
- 24. A device for producing contact lenses, comprising a plurality of individual reusable moulds, wherein each mould has a female mould half, a male mould half, wherein the female and male mould halves, independently of each other, include one or more guide surfaces, wherein the guide surfaces of the female and male mould halves provide centering and adjusting elements which are all necessary for substantially accurate and automatic centering/positioning of the female and male mould halves in relation to each other in each individual reusable mould, without additional adjustment work, when the female and male mould are joined to form a mould cavity defining the shape of a contact lens to be produced, wherein each mould is intended to accommodate a crosslinkable material and is designed to be at least partly transparent to energy which is supplied from outside and effects the crosslinking of the crosslinkable material, wherein the plurality of the individual reusable moulds are combined into a unit for transporting and for closing the individual moulds simultaneously, and wherein accurate alignments of the female mould halves and the male mould halves of each individual mould is individually and automatically performed by means of the guide surfaces of the female and male mould halves of each individual mould when the moulds are closed simultaneously.
Specification