Block-Free Lens Support for Lenses Surfacing

Abstract

The invention relates to a lens supporting part (100) for supporting a lens (L) in a surface machining process, in which one (L1) of two opposite side surfaces (L1, L2) of the lens (L) is processed. The lens supporting part (100) comprises a plurality of support elements (110) that are relatively moveable with respect to each other and that together form a lens seat (120) with a curvature for supporting the lens (L) on its other side surface (L2) against forces generated in the surface machining process. The lens supporting part (100) comprises an adjustment mechanism (130) for displacing during processing at least some of the support elements (110) relatively to each other to adjust the curvature of the lens seat (120) to a defined curvature independently from a lens (L) being seated on the support elements (110). The invention is also directed to a system (500) and a method for surface processing at least one of the side surfaces (L1, L2) of a lens (L) that utilize the lens supporting part (100) of the invention, respectively.

Claims

1. A lens supporting part (100) for supporting a lens (L) in a surface machining process, in which one (L1) of two opposite side surfaces (L1, L2) of the lens (L) is processed, wherein the lens supporting part (100) comprises a plurality of support elements (110) being relatively moveable with respect to each other and together forming a lens seat (120) with a curvature for supporting the lens (L) on its other side surface (L2) against forces caused in the surface machining process, and an adjustment mechanism (130) for displacing at least some of the plurality of support elements (110) relatively to each other during processing to adjust the curvature of the lens seat (120) to a defined curvature independently from a lens (L) being seated on the support elements (110).

2. The lens supporting part (100) according to claim 1, wherein the adjustment mechanism (130) is configured to move at least some of the plurality of support elements (110) independently from each other to obtain the defined curvature, and/or wherein the adjustment mechanism (130) is configured such that at least one, preferably each, of the support elements (110) is relatively movable to a lens (L) being seated on the support elements (110).

3. The lens supporting part (100) according to claim 1, wherein the adjustment mechanism (130) is configured to move, preferably slide, the respective support elements (110) in a direction, which is transverse, preferably orthogonal, to the lens seat (120) and/or that is a direction parallel to a holding force for holding the lens (L) on the lens supporting part (100), to adjust the curvature of the lens seat (120).

4. The lens supporting part (100) according to claim 1, wherein the support elements (110) each have a distal end (111), preferably each of the distal ends (111) together forming the lens seat (120), wherein preferably the distal ends (111) each comprise or are made of an elastic material for supporting the lens (L), and/or wherein preferably the support elements (110) each extend, preferably along a longitudinal axis, between the distal end (111) and a proximal end (112) for being coupled to the adjustment mechanism (130).

5. The lens supporting part (100) according to claim 1, wherein at least one of the support elements (110), forms an outer circumferential sealing edge (113) of the lens seat (120) to allow for a circumferential sealing of a lens (L) being seated on the lens seat (120), wherein preferably the at least one support element (110) forming the outer circumferential sealing edge (113) is fixed relatively to other support elements (110) and/or to a lens (L) being seated on the support elements (110).

6. The lens supporting part (100) according to claim 1, wherein the lens seat (120) is configured to be fluidly connectable to a vacuum unit (200) or the lens supporting part (100) further comprising a vacuum unit (200) that is fluidly connected to the lens seat (120) to apply a vacuum in a suction space (210) between the lens seat (120) and a lens (L) being seated on the lens seat (120), preferably for creating a holding force for holding the lens (L) on the lens seat (120), and wherein preferably vacuum passages (115) are formed between at least some of the support elements (110) for connecting the vacuum unit (200) with the lens seat (120) and preferably with the suction space (210).

7. The lens supporting part (100) according to claim 1, wherein the adjustment mechanism (130) is configured to be connectable to at least one actuator (300) or wherein the adjustment mechanism (130) comprises at least one actuator (300), such as an electric motor or pneumatic cylinder, preferably for displacing the support elements (110) relatively to each other, and/or wherein the adjustment mechanism (130) comprises a blocking part that is movable between a first position, where the support elements (110) are fixed in their relative position to each other and preferably to a lens (L) being seated on the lens seat (120), and a second position, where the support elements (110) are relatively movable with respect to each other and preferably to a lens (L) being seated on the lens seat (120), wherein preferably the blocking part is a movable clamp.

8. The lens supporting part (100) according to claim 1, wherein the adjustment mechanism (130) further comprises a connecting mechanism (140), preferably for each of the support elements (110) to be moved, to transmit, preferably directly or indirectly, an actuation force of an, preferably the, actuator (300) to the respective support element (110), preferably such that said support element (110) is linearly moved.

9. The lens supporting part (100) according to claim 1, wherein the support elements (110) are formed and/or arranged in a ring shape, preferably with a plurality of ring diameters and more preferred coaxially arranged to form the lens seat (120).

10. A system (500) for surface processing of at least one of two opposite side surfaces (L1, L2) of a lens (L), comprising a lens supporting part (100) for supporting the lens (L) during the surface machining process according to claim 1, and a surface processing unit (510) for processing the one side surface (L1) of the lens (L), such as a lens cutting or lens polishing device; a surface information supply unit (520) for supplying a geometry of the other side surface (L2) of the lens (L), such as a camera, a pressure sensor, a laser sensor or a database; a control unit (530) for determining and setting a defined curvature of the lens seat (120) based on the supplied geometry of the other side surface (L2) of the lens (L), and for controlling the adjustment mechanism (130) to displace the support elements (110) relative to each other to obtain the defined curvature of the lens seat (120).

11. The system (500) according to claim 10, wherein the control unit (530) is configured to preferably continuously determine and set the defined curvature of the lens seat (120) preferably further based on detected process parameters, like mechanical stresses occurring during the processing step, and/or a desired shape for the finished lens (L).

12. The system (500) according to claim 10, wherein the system (500) comprises a spindle (540) for rotating the lens supporting part (100) during the surface machining process, wherein the lens supporting part (100) and the spindle (540) are arranged coaxially and/or are detachably coupled to each other.

13. A method for surface processing at least one of two opposite side surfaces (L1, L2) of a lens (L), comprising: providing a system (500) for surface processing at least one of two opposite side surfaces (L1, L2) of a lens (L) according to claim 10; supplying a geometry of the other side surface (L2) of the lens (L), preferably with the surface information supply unit (520); determining and setting a defined curvature of the lens seat (120) based on the supplied geometry of the other side surface (L2) of the lens (L), preferably with the control unit (530); adjusting the curvature of the lens seat (120) independently from a lens (L) being seated thereon to obtain the defined curvature of the lens seat (120), preferably with the adjustment mechanism (130); supporting the lens (L) with its other side surface (L2) on the lens seat (120) with its defined curvature; preferably attaching the lens (L) to the lens seat (120) by activating a suction force or vacuum as a holding force, preferably with the vacuum unit (200), and preferably centring the lens (L) on the lens seat (120); and processing the at least one side surface of the lens (L) to a desired shape, preferably with the surface processing unit (510).

14. The method according to claim 13, wherein the method further comprises, during the processing step, the steps of: continuously determining and setting the defined curvature of the lens seat (120) further based on detected process parameters, like mechanical stresses occurring during the processing step, positional information (311) determined by sensors of the actuators, and/or a desired shape for the finished lens (L), preferably such that a curvature of the other side surface (L2) of the lens (L) at the beginning of the processing is maintained, and adjusting the curvature of the lens seat (120) independently from the lens (L) being seated thereon to obtain the defined curvature of the lens seat (120).

15. The method according to claim 13, wherein the processing step comprises a lens surface rough cutting step, where the lens (L) is secured on both side surfaces (L1, L2) between the lens supporting part (100) and an additional holding device, which is preferably arranged opposite of the lens supporting part (100) with respect to the lens (L), and a subsequent finishing step, where the lens (L) is secured only by the lens supporting part (100).

Description

BRIEF DESCRIPTION OF DRAWINGS

[0068] Further features, advantages and objects of the invention will become apparent for the skilled person when reading the following detailed description of embodiments of the invention and when taking in conjunction with the figures of the enclosed drawings.

[0069] In case numerals were omitted from a figure, for example for reasons of clarity, the corresponding features may still be present in the figure.

[0070] FIG. 1 shows schematically a lens in a front view and a side view in the beginning and the end of surface processing.

[0071] FIG. 2A shows schematically a side view of the connection between a lens and a surfacing block of the prior art at the beginning of a surface machining process.

[0072] FIG. 2B shows schematically a side view of the connection between a lens and a surfacing block of the prior art at the end of a surface machining process.

[0073] FIG. 3 shows schematically an embodiment of a lens supporting part according to the present invention.

[0074] FIG. 4 shows schematically an embodiment of a system of the present invention with a simplified illustration of a further embodiment of the lens supporting part according to the present invention.

DETAILED DESCRIPTION

[0075] FIG. 1 shows exemplary profiles of a lens L at the beginning and the end of a surface machining process. FIGS. 2A and 2B illustrate known challenges that exist in connecting a lens L with a support block B100 known from the prior art and that were described in more detail above. FIGS. 3 and 4 show different aspects of different embodiments of the present invention.

[0076] For instance, a first aspect of the invention relates to a lens supporting part 100 according to the invention. Embodiments of the lens supporting part 100 are illustrated in FIGS. 3 and 4. The lens supporting part 100 is suitable for supporting lens L in a surface machining process. For example, the lens supporting part 100 may be a jig, a chuck, a workpiece holder, and/or an adapter suitable to be used in a lens surfacing process.

[0077] The lens L comprises two opposite side surfaces L1, L2. This is exemplarily illustrated in all Figures. In the surface machining process, one side surface L1 of the lens L is to be processed. At the end of the processing, the lens L may have a newly shaped one side surface L11. This is exemplarily illustrated in FIG. 1. Preferably, the lens L may comprise a circumferential edge L3 that extends between the two side surfaces L1, L2. Preferably, the lens L may be made of a transparent and/or translucent material, e.g. a plastic material, such as polycarbonate, or glass. More preferred, the lens L may be a lens blank. Preferably, one side surface of the lens blank (e.g. its back surface) may be used for customization in a surface machining process while the other side surface of the lens blank (e.g. its front surface) may be already in its finished state, i.e. may comprise already its intended curvature and may be already polished. The lens L may comprises a coating for polarisation or light blocking. However, this is only an example and the lens L may be a lens blank with both side surfaces requiring surface processing. The lens L may comprise side surfaces L1, L2 that may be convex and/or concave. The lens L may comprise an optical axis OA that may be a normal of a symmetry plane of the lens L. The lens L may comprise spherically shaped side surfaces L1, L11, L2. It is also conceivable that the lens L has more than one optical axis or differently shaped side surfaces L1-L2.

[0078] The lens supporting part 100 comprises a plurality of support elements 110. In FIGS. 3 and 4, the lens supporting part 100 is exemplarily illustrated with six support elements 110. However, this is only an example and the lens supporting part 100 may comprise any number of support elements 110 greater or equal than two. Preferably, the support elements 110 may each extend along a longitudinal axis. Moreover, (each or some of) the support elements 110 may preferably extend between a distal end 111 and a proximal end 112. This is exemplarily illustrated in FIGS. 3 and 4. The support elements 110 may have a ring shape. For example, the support elements 110 may be long hollow shafts. Each of the ring-shaped support elements 110 may have a different diameter and may be arranged coaxially as exemplarily illustrated in FIGS. 3 and 4. However, this is only an example and the support elements 110 may have various shapes and may be arranged differently. For instance, the support elements 110 may be slats or plates that preferably they may be arranged in a circle such that they all are directed towards a common centre. Preferably, at least one (or all) of the support elements 110 may be made of a rigid material, such as metal (e.g. stainless steel) or a hard plastic. The support elements 110 may have a tensile stiffness between 150 MPa and 250 MPa. Preferably, material(s) used for the support elements 110 may have a surface hardness in the range between surface harnesses found with hard steel (e.g. 62 HRC) and hard plastic material (e.g. 60-70 ShD).

[0079] Moreover, the support elements 110 may each have their distal end 111 made of an elastic material for supporting and/or contacting the lens L. For example, a material with a surface hardness ranging between the surface hardness found for soft rubber (e.g. 60 ShA) and soft plastic material (e.g. 60-70 ShD) may be used for the distal end 111. For example, the support elements 110 may have a rubber coating or gasket provided on their respective distal end 111 to avoid scratching the other side surface L2 when the support elements 110 come into contact with the lens L as exemplarily illustrated in FIGS. 3 and 4.

[0080] The support elements 110 are relatively moveable with respect to each other. Moreover, the support elements 110 form together a lens seat 120 with a curvature for supporting the lens L on its other side surface L2 against forces caused in the surface machining process. Preferably, each of the distal ends 111 together may form the lens seat 120. FIGS. 3 and 4 illustrate exemplarily that by increasing the number of support elements 110 it may be possible to increase the resolution for forming the curvature of the lens seat 120. In FIGS. 3 and 4, the lens seat 120 is exemplarily shown with a convex shaped surface that is formed by the distal ends 111 of the support elements 110. Each of the support elements 110 may be provided relatively movable to the lens L when the lens L is seated on the support elements 110.

[0081] At least one of the support elements 110 may preferably form at its distal end 111 an outer circumferential sealing edge 113 of the lens seat 120. For example, the circumferential sealing edge 113 may be a (rubber) gasket, such as an O-ring. The circumferential sealing edge 113 may allow for a circumferential sealing of the lens L being seated on the lens seat 120 as exemplarily illustrated in FIG. 3. Preferably, the support element 110 that forms the outer circumferential sealing edge 113 may be fixed relatively to other support elements 110 and preferably also to the lens L when being seated on the support elements 110. This is shown by way of example in FIGS. 3 and 4.

[0082] Preferably, the support element(s) 110 that form(s) the outer circumferential sealing edge 113 may form a main body of the lens supporting part 100. However, the main body may be formed by a separate component instead. For example, the main body may be a cartridge or a container. The main body may be arranged to be coupled to a machine or system for surface processing. Preferably, the support elements 110 may be arranged inside the main body around a common axis. Therein, the support elements 110 may be preferably arranged such that for processing they may be brought in alignment with a rotational axis RA of a machine spindle (e.g. later described spindle 540). FIGS. 3 and 4 indicate this exemplarily. Preferably, the lens L may be arranged on the lens seat 120 such that its optical axis is aligned with the rotational axis RA.

[0083] Preferably, the lens supporting part 100 may further comprise a vacuum unit 200. The vacuum unit 200 may be a vacuum ejector, a displacement or kinetic vacuum pump, for example. In FIG. 4, the vacuum unit 200 is exemplarily displayed as part of a system 500, which will be described in more detail below. The vacuum unit 200 may be fluidly connected/connectable to the lens seat 120 to apply a vacuum in a suction space 210 between the lens seat 120 and the lens L being seated on the lens seat 120. This is exemplarily illustrated in FIG. 3. With the vacuum unit 200, a holding force for holding (and/or securing) the lens L on the lens seat 120 may be created. Therein, the lens supporting part 100 may comprise at least one vacuum passage 115 for connecting the vacuum unit 200 with the lens seat 120 and the suction space 210. In FIG. 3, the vacuum passages 115 are exemplarily shown as being formed between at least some of the support elements 110 for connecting the vacuum unit 200 with the lens seat 120. Therein, the support elements 110 may be arranged with a small gap between each other. In FIG. 4, the vacuum passage 115 is exemplarily shown as a single duct that leads to the centre of the lens seat 120 and that may be provided as a through hole in one of the support elements 110.

[0084] The lens supporting part 100 further comprises an adjustment mechanism 130 for displacing at least some of the plurality of support elements 110 relatively to each other during processing to adjust the curvature of the lens seat 120 to a defined curvature independently from a lens L being seated on the support elements 110. The adjustment mechanism 130 is exemplarily illustrated in FIGS. 3 and 4. Preferably, the adjustment mechanism 130 may be configured to move at least some of the plurality of support elements 110 independently from each other to obtain the defined curvature.

[0085] The support elements 110 may be coupled to the adjustment mechanism 130 via their proximal ends 112. Therein, for example, the adjustment mechanism 130 may comprise a connecting mechanism 140. For example, the connecting mechanism 140 may (mechanically and/or electrically) link the support element 110 with the adjustment mechanism 130. For instance, the connecting mechanism 140 may convert or transfer an actuation (e.g. a control motion or a force) of the adjustment mechanism 130 to the (individual) support elements 110. The connecting mechanism 140 may define the kinematics between the adjustment mechanism 130 and the support element 110. The connecting mechanism 140 is exemplarily illustrated in FIGS. 3 and 4 as connecting portion between the support elements 110 and corresponding actuators 300 for displacing, e.g. during processing, at least some of the support elements 110. Preferably, each of the support elements 110 may be displaced through the connecting mechanism 140 directly/indirectly transmitting an actuation force of the actuators 300 to the corresponding support element 110, e.g. so that the respective support element 110 may be linearly moved. For example, in one of its simplest configurations, the connecting mechanism 140 may be a mechanical connection, such as a screw connection, between the adjustment mechanism 130 and the respective support element 110.

[0086] As mentioned above, the adjustment mechanism 130 or the system 500 may comprise at least one actuator 300. In general, the actuator 300 may be a component that is configured to (actively) generate a (mechanical or electrical) force for actuating (i.e. displacing, for example, in a controlled/defined manner) the support elements 110 (to be moved). Therein, the actuator 300 may be a different component depending, for example, on the design of the adjustment mechanism 130 and/or the connecting mechanism 140. Preferably, at least one actuator 300 may be provided for each of the support elements 110 that is to be displaced during the surface machining process. The actuator 300 may be an electric motor, such as illustrated in FIGS. 3 and 4, or it may be a pneumatic cylinder or a piezo motor. However, it is also conceivable that the actuator 300 may be a mechanical break or an eddy current break. These are only examples and do not represent a complete enumeration. Preferably, the actuator 300 may be controllable, for example by a computational unit or machine control unit (such as later described control unit 530). The actuator 300 may comprise a sensor unit 310 for determining positional information, such as a relative position of the actuator 300 with respect to the lens L or with respect to the outer circumferential sealing edge 113. For example, the actuator 300 may be battery powered and/or may be controllable through a wireless receiver for receiving control commands from the machine control unit. The actuator(s) 300 may be arranged relatively movable and/or static (i.e. fixed/immovable) relative to the support elements 110 preferably in operation.

[0087] Preferably, the adjustment mechanism 130 may be configured to move the respective support elements 110 in a direction, which is transverse (e.g. orthogonal) to the lens seat 120, in order to adjust the curvature of the lens seat 120. In the examples illustrated in FIGS. 3 and 4, the adjustment mechanism 130 is configured to move the respective support elements 110 in a direction parallel to the holding force for holding the lens L on the lens supporting part 100, which is generated by the vacuum unit 200. Preferably, the adjustment mechanism 130 and/or the support elements 110 may be configured to slide.

[0088] The adjustment mechanism 130 may be configured to temporarily block (freeze) the movement of the support elements 110. Therein, the adjustment mechanism 130 may comprise a blocking part that may be movable between a first position, where the support elements 110 are fixed in their relative position to each other (and preferably also to the lens L when being seated on the lens seat 120), and a second position, where the support elements 110 are relatively movable with respect to each other (and preferably also to the seated lens L). Preferably, the blocking part may be a movable clamp. Alternatively, it is also conceivable that the actuators 300 block any further movement of the support elements 110 without receiving a corresponding control signal.

[0089] A further aspect of the present invention relates to a system 500 for surface processing at least one of the two opposite side surfaces L1, L2 of the lens L. The system 500 is exemplarily illustrated in FIG. 4. For example, the system 500 may be a machine for surface processing of lenses.

[0090] The system 500 comprises the lens supporting part 100 as described above. Unlike in FIG. 3, the actuators 300 may be provided as part of the system 500. However, this is only an example.

[0091] Furthermore, the system 500 comprises a surface processing unit 510 for processing at least the one side surface L1 of the lens L. For example, the surface processing unit 510 may be a drill, a lens cutting or a lens polishing device. In FIGS. 3 and 4, the surface processing unit 510 is exemplarily illustrated as a tool bit. However, this is only an example and other tools for roughing, polishing, surfacing can be used instead.

[0092] The system 500 further comprises a surface information supply unit 520 for supplying a geometry of at least the other side surface L2 of the lens L. The surface information supply unit 520 may be a camera, a pressure sensor or a laser sensor. However, it is also conceivable that the surface information supply unit 520 may be a database or an interface, such as a connector or data link, to a database. Preferably, the surface information supply unit 520 may be a contactless sensor such as exemplarily illustrated in FIG. 4. The surface information supply unit 520 may be arranged outside of or (e.g. integrally provided) within the lens supporting part 100.

[0093] The system 500 further comprises a (preferably “the” aforementioned) control unit 530 for determining and setting a defined curvature of the lens seat 120 based on the supplied geometry of the other side surface L2 of the lens L and for controlling the adjustment mechanism 130 to displace the support elements 110 relative to each other to obtain the defined curvature of the lens seat 120. For example, the control unit 530 may be a machine control device as exemplarily illustrated in FIG. 4. However, it is also conceivable that the control unit 530 may be part of the control unit of one of the actuators 300 (e.g. a servomotor). For example, the control unit 530 may comprise the surface information supply unit 520, e.g. the surface information supply unit 520 may be the memory of the control unit 530 or it may be mounted on the control unit 530.

[0094] Preferably, the control unit 530 may be configured to (continuously) determine and set the defined curvature of the lens seat 120. For this, the control unit 530 may comprise signal connections that connect the individual components of the system 500 with the control unit 530. This is exemplarily illustrated in FIG. 4. For example, the actuator 300 may transmit to the control unit 530 positional information 311 that is determined by the sensor unit 310 of the actuator 300 or by a separate sensor provided in the system 500. Further, the control unit 530 may be configured to set and adapt the level and/or application location of the suction force or vacuum created by the vacuum unit 200. Also, the control unit 530 may be configured to (continuously) determine and set the defined curvature of the lens seat 120 based on the (so) detected process parameters, but also on mechanical stresses occurring during a processing step and/or a desired shape for the finished lens L. Therefore, the control unit 530 may be connected to the surface information supply unit 520, e.g. via a signal connection.

[0095] Preferably, the system 500 may further comprise a spindle 540 for rotating the lens supporting part 100 during the surface machining process along the rotational axis RA. This is exemplarily illustrated in FIG. 4 but also indicated in FIG. 3. The lens supporting part 100 may be part of the spindle 540. Alternatively, the lens supporting part 100 may be arranged coaxially and is detachably coupled thereto as exemplarily illustrated in FIG. 4. The control unit 530 may be connected to the spindle 540, e.g. via a signal connection, to control and set the rotational speed during surface processing.

[0096] A further aspect of the present invention relates to a method for surface processing at least one of the two opposite side surfaces L1, L2 of the lens L.

[0097] The method comprises a step, in which the above described system 500 is provided to facilitate surface processing at least one of the two opposite side surfaces L1, L2. A geometry of at least one of the two side surfaces L1, L2 of the lens L is supplied preferably with the surface information supply unit 520. Based on the so supplied geometry of the respective side surface L1, L2, a defined curvature of the lens seat 120 is determined and set, preferably by the control unit 530. The curvature of the lens seat 120 is adjusted (e.g. during processing) independently from the lens L being seated thereon to obtain the defined curvature of the lens seat 120, preferably by the adjustment mechanism 130. The lens L is supported on the lens seat 120 with its defined curvature at the side surface L1, L2 that is not processed.

[0098] The lens L may be attached to the lens seat 120 by activating a suction force or vacuum as a holding force, preferably with the vacuum unit 200. Preferably, when attaching the lens L on the lens seat 120, the lens L may be centred on the lens seat 120 through the suction force or vacuum pulling the lens L onto the outer circumferential sealing edge 113 into the right position. For example, the lens seat 120 may be provided with structures of a self-centring mechanism for the lens L.

[0099] The at least one side surface of the lens L to be processed is processed to a desired shape, preferably with the surface processing unit 510.

[0100] Preferably, during the processing step, the defined curvature of the lens seat 120 may be continuously determined and set based on detected process parameters, like mechanical stresses occurring during the processing step, the positional information 311 determined by the sensor unit 310, and/or based on a desired shape for the finished lens L. For example, by setting the defined curvature the adjustment mechanism 130 may be (actively) controlled to displace at least some of the support elements 110 relatively to each other.

[0101] Preferably, the control unit 530 may be configured such that a curvature of the side surface L2 of the lens L (which is not to be processed) is maintained in its shape at the start of the processing. Alternatively or additionally, during the (still ongoing) processing step, the curvature of the lens seat 120 may be adjusted independently from the lens L being seated thereon to obtain the defined curvature of the lens seat 120. Therein, the processing step may comprise a lens surface rough cutting step, where the lens L is secured on both side surfaces L1, L2 between the lens supporting part 100 and an additional holding device (not illustrated). The additional holding device may be arranged opposite of the lens supporting part 100 with respect to the lens L seated thereon. For completeness and clarification purposes, reference is made to WO 2015/059007 A1, where an example for the additional holding device is provided. A subsequent finishing step may be part of the processing step, where the lens L is secured only by the lens supporting part 100, for example by applying a suction force or vacuum.

[0102] The invention is not limited by the embodiments as described hereinabove, as long as being covered by the appended claims. All the features of the embodiments described hereinabove can be combined in any possible way and be provided interchangeably.