POLISHING TOOL, POLISHING SYSTEM AND METHOD OF POLISHING

Abstract

The invention relates to a polishing tool (100) for polishing a spectacle lens (L) in a surface machining process, which comprises a tool body (110) for being rotatably supported about a rotational axis (RA1). The tool body (110) comprises a polishing surface (130) being outwardly exposed at a first axial end (101) of the tool body (110). Therein, the polishing surface (130) is axially bulged convexly or concavely with respect to the rotational axis (RA1) for polishing an optical surface (L1, L2) of the spectacle lens (L). The tool body (110) further comprises a channel (140) that extends axially through the tool body (110) from an inlet (142) to an outlet (141) to supply the polishing surface (130) with a polishing agent. The inlet (142) is provided at a second axial end (102) being opposite to the first axial end (101) with respect to the rotational axis (RA1). The outlet (141) is provided at the first axial end (101). The polishing surface (130) comprises at least one groove (150) that extends radially away from the outlet (141) to the perimeter of the polishing surface (130) to distribute the polishing agent across the polishing surface (130). The invention also relates to a system (200) and a method for polishing a spectacle lens (L) in a surface machining process with said polishing tool (100).

Claims

1. A polishing tool (100) for polishing a spectacle lens (L) in a surface machining process, comprising a tool body (110) for being rotatably supported about a rotational axis (RA1), wherein the tool body (110) comprises a polishing surface (130) being outwardly exposed at a first axial end (101) of the tool body (110), the polishing surface (130) being axially bulged convexly or concavely with respect to the rotational axis (RA1) for polishing an optical surface (L1, L2) of the spectacle lens (L), wherein the tool body (110) comprises a channel (140) extending axially through the tool body (110) from an inlet (142), which is provided at a second axial end (102) being opposite to the first axial end (101) with respect to the rotational axis (RA1), to an outlet (141), which is provided at the first axial end (101), to supply the polishing surface (130) with a polishing agent, and wherein the polishing surface (130) comprises at least one groove (150) that extends radially away from the outlet (141) to the perimeter of the polishing surface (130) to distribute the polishing agent across the polishing surface (130).

2. The polishing tool (100) according to claim 1, wherein the groove (150) extends radially along a main extension direction, preferably in a linear, straight, curved and/or arcuate manner, more preferred in a wave or zigzag manner.

3. The polishing tool (100) according to claim 1, wherein the groove (150) comprises different sections, preferably straight, angled, arcuate and/or curved sections, wherein adjoining sections extend circumferentially in opposite directions, wherein preferably the adjoining sections are connected to each other by an arcuate portion that more preferred forms a gradual transition between the respective adjoining sections.

4. The polishing tool (100) according to claim 1, wherein the groove (150) has a width (W) ranging from 0.1 mm to 1.0 mm, or from 0.2 mm to 0.8 mm, or from 0.4 mm to 0.6 mm, or of 0.5 mm, and/or wherein the groove (150) has a depth (T) ranging from 0.1 mm to 1.0 mm, or from 0.2 mm to 0.8 mm, or from 0.4 mm to 0.6 mm, or of 0.5 mm.

5. The polishing tool (100) according to claim 1, comprising a plurality of the said grooves (150), wherein the grooves (150) are preferably radially diverging and/or preferably distributed, more preferred evenly distributed about the outlet (141) or the rotational axis (RA1), wherein the grooves (150) preferably have the same or at least partially a different shape and/or cross-section.

6. The polishing tool (100) according to claim 1, wherein the tool body (110) comprises a polishing film (113) forming the first axial end (101) of the tool body (110), wherein the polishing film (113) comprises the outlet (141) and the groove (150), and wherein preferably the polishing film (113) has a thickness ranging from 0.5 mm to 2.5 mm, or from 0.8 mm to 2.0 mm, or of 1.3 mm.

7. The polishing tool (100) according to claim 1, wherein the tool body (110) comprises a base portion (111) for rotatably supporting the polishing tool (100), wherein the base portion (111) preferably comprises the inlet (142), and wherein preferably the tool body (110) further comprises a holder portion (112) being sandwiched between the polishing film (113) and the base portion (111), wherein preferably the holder portion (112) is deformable for adapting to the optical surface (L1, L2) of the spectacle lens (L).

8. The polishing tool (100) according to claim 1, wherein the channel (140) extends along the rotational axis (RA1) of the polishing tool (100) and preferably, if present, penetrating the polishing film (113), the base portion (111) and the holder portion (112), respectively.

9. The polishing tool (100) according to claim 1, wherein the tool body (110), preferably the base portion (111) if present, comprises a port (143) for fluidly connecting the channel (140) with a polishing agent supply unit (240), wherein preferably the port (143) comprises a gasket (144) for radially sealing against the polishing agent supply unit (240) to prevent the polishing agent from leakage and to enable only the polishing agent entering the channel (140) via the inlet (142).

10. A system (200) for polishing of at least one optical surface (L1, L2) of a spectacle lens (L), comprising a surface processing unit (210) for processing the optical surface (L1, L2) of the spectacle lens (L), wherein the surface processing unit (210) comprises the polishing tool (100) according to claim 1, and a polishing agent supply unit (240) being fluidly connected to the channel (140) via the inlet (142) of the polishing tool (100) to supply the groove (150) or grooves (150) of the polishing surface (130) with a polishing agent via the channel (140) and the outlet (141), a lens support unit (220) for supporting the spectacle lens (L) during the polishing process, and a drive unit to apply a relative motion between the polishing tool (100) and the lens support unit (220) at least by rotating the polishing tool (100) about the rotational axis (RA1) to allow polishing of the optical surface (L1, L2).

11. The system (200) according to claim 10, wherein the relative motion further comprises tilting, pivoting and/or linearly moving the polishing tool (100) relatively to the lens support unit (220) to apply the relative motion, and/or wherein the drive unit is preferably adapted to rotate the lens support unit (220) about a second rotational axis (RA2) to apply the relative motion, and/or wherein the drive unit is preferably adapted to displace the polishing tool (100) relative to the lens support unit (220) to obtain a defined distance therebetween.

12. The system (200) according to claim 10, further comprising a control unit (230) for controlling the relative motion by the drive unit based on processing features, like the lens type, form and thickness, the polishing tool type, the polishing agent type, wherein preferably the control unit (230) is configured to adapt a relative rotational speed between the optical surface (L1, L2) and the polishing tool (100), and/or a pressure for supplying the polishing agent to the polishing tool (100), and/or a flow rate of the polishing agent.

13. The system (200) according to claim 10, wherein the polishing agent supply unit (240) is fluidly connected to the polishing tool (100) through the port (143), wherein preferably the gasket (144) radially seals against the polishing agent supply unit (240) to prevent the polishing agent from leakage and to enable the polishing agent entering the channel (140) only via the inlet (142).

14. A process of polishing an optical surface (L1, L2) of a spectacle lens (L) comprising: providing a system (200) for surface processing having a polishing tool (100) according to claim 1, seating a spectacle lens (L) in a lens support unit (220) of the system (200), relatively rotating the polishing tool (100) with respect to the spectacle lens (L), delivering a polishing agent through the channel (140) to the polishing surface (130) facing an optical surface (L1, L2) of the spectacle lens (L) to be polished, so that the polishing agent is delivered through the grooves (150) radially outwards from the outlet (141) to distribute the polishing agent across the polishing surface (130) for polishing the optical surface (L1, L2).

15. The process of claim 14, further comprising controlling a thickness of a layer of the polishing agent between the optical surface (L1, L2) and the polishing surface (130) by adapting a flow rate and/or supply pressure of the polishing agent based on a rotational speed of the polishing tool (100) and/or the spectacle lens (L).

Description

BRIEF DESCRIPTION OF DRAWINGS

[0053] 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. In case numerals have been omitted from a figure, for example for reasons of clarity, the corresponding features may still be present in the figure.

[0054] FIG. 1 shows schematically a lens in a front view and a side view.

[0055] FIG. 2 shows schematically a customized lens in a side view at the end of a surface machining process.

[0056] FIG. 3 shows schematically a side view of the connection between a lens and a lens support at the beginning of a surface machining process.

[0057] FIG. 4 shows schematically a side view of a customized lens in a lens support during a surface machining process.

[0058] FIGS. 5 and 6 show schematically a side view of a customized lens in a lens support being polished in a surface machining process of the prior art.

[0059] FIGS. 7 and 8 show schematically a side view of an experimental setup for testing polishing tools for polishing a customized lens in a lens support, respectively.

[0060] FIG. 9 shows a schematic sectional view of an embodiment of a polishing tool according to the present invention.

[0061] FIG. 10 shows a schematic front view of an embodiment of a polishing tool according to the present invention.

[0062] FIG. 11 shows a schematic view of an embodiment of a system according to the present invention with the polishing tool of FIG. 9.

DETAILED DESCRIPTION

[0063] FIG. 1 shows exemplary a profile of a lens L before the start of a surface machining process. FIG. 2 shows an example of a customized lens L at the end of a surface machining process. FIGS. 3 and 4 show different steps of a lens generating process. FIGS. 5 and 6 highlight known problems existing in the prior art. Each of FIGS. 7 and 8 illustrates an experimental setup for identifying problems existing in polishing processes. FIGS. 9 to 11 show different views and aspects of embodiments of the invention.

[0064] For instance, a first aspect of the invention relates to a polishing tool 100 for polishing a spectacle lens L in a surface machining process. Embodiments of the polishing tool 100 are exemplarily illustrated in FIGS. 7 to 9.

[0065] Generally, a lens may be understood, for example, as any transmissive optical device that is adapted to change the course of light by refraction. For example, the lens L may be an ophthalmologic lens, such as corrective or prescription lenses. FIGS. 1 and 2 show examples for the lens L. The lens L may have two opposite optical (side) surfaces L1, L2 and a circumferential edge L3. The optical (side) surfaces L1, L2 may be convex and/or concave. Typically, the lenses L may be made of a transparent and/or translucent material, e.g. a plastic material for spectacle lenses, such as polycarbonate, or glass.

[0066] In a surface machining process, typically only one of the two optical surfaces L1, L2 may be processed while the other one of the two side surfaces L1, L2 of the lens L is supported by a lens support unit 220. This is exemplarily illustrated in FIGS. 3 to 6 and 11. Naturally, either or both of the two side surfaces L1, L2 of the lens L may be processed in the surface machining process.

[0067] The surface machining process may be started by choosing a lens blank, such as the lens L exemplarily shown in FIG. 1, with a front surface L2 most suitable for the vision enhancing application, which may remain unchanged. In comparison, the rear surface L1 of the lens blank L may be processed to generate a customized (progressive) lens L, as exemplarily shown in FIG. 2.

[0068] The surface machining process may typically comprise, for example, any surfacing or manufacturing step(s) for the generation of optical devices, such as cribbing (i.e. reducing an outer diameter of the lens blank L in a milling process), roughing (i.e. grinding one of the optical surfaces L1, L2 to the approximate curvature and thickness), smoothing (i.e. grinding one of the optical surfaces L1, L2 to the exact curvature and thickness), bevelling (i.e. cutting the lens L to the shape of eyeglass frames) and polishing (i.e. making the lens L smooth; providing regular transmission and reduce specular reflection). However, these are only examples and not a complete enumeration.

[0069] The polishing tool 100 is suitable (and configured) for being used in such a surface machining process, for example. Further, the polishing tool 100 is suitable (and configured) for polishing spectacle lenses; consequently, the polishing tool 100 may be suitable for following curvatures typically existing with spectacle lenses and for processing typical materials used for spectacle lenses.

[0070] The polishing tool 100 comprises a tool body 110 for being rotatably supported about a rotational axis RA1. This is exemplarily indicated in FIGS. 9 and 11. The rotational axis RA1 may be a body axis or a symmetry axis of the tool body 110 and/or an axis offset from the polishing tool 100.

[0071] The tool body 110 comprises a first axial end 101 and a second axial end 102, which is provided opposite to the first axial end 101 with respect to the rotational axis RA1. Preferably, the tool body 110 may extend (continuously) along (with) the rotational axis RA1 from the first axial end 101 to the second axial end 102. FIGS. 9 and 11 show this exemplarily. The tool body 110 may have any shape or form, such as a cylindrical shape. For example, the tool body 110 may be coaxial with the rotational axis RA1.

[0072] The tool body 110 may comprise a layered and/or a continuous structure, for example. In FIGS. 9 and 11, the tool body 110 is exemplarily shown as being composed of different layers. The tool body 110 may comprise any number of layers. The respective layers may be connected to each other by adhesive bond, like gluing, or by a mechanical connection, such as a screw. However, these are only examples and not a complete enumeration.

[0073] At the first axial end 101, the tool body 110 comprises a polishing surface 130, which is exposed to the outside. FIG. 11 illustrates exemplarily how the outwardly exposed configuration of the polishing surface 130 can facilitate an interaction between the polishing tool 100 and the lens surface L1. The polishing surface 130 is axially bulged convexly or concavely with respect to the rotational axis RA1 for polishing an optical surface L1, L2 of the lens L. For example, depending on the type of the lens L, e.g. a converging or diverging lens, the polishing surface 130 may have a curved (round) shape projecting outwardly (convex) or retracting inwardly (concave). FIGS. 9 and 11 show the polishing surface 130 exemplarily being axially bulged convexly with respect to the rotational axis RA1. Preferably, the polishing surface 130 may be bulged such that the polishing surface 130 may have a curvature at least similar or higher than the optical surface L1, L2. More preferred, the polishing surface 130 may be smaller in size than the optical surface L1, L2 of the lens L. For example, the polishing surface 130 may cover 1/50, 1/20, 1/10, ?, ?, or ? of the (entire) area of the optical surface L1, L2. The polishing surface 130 may form an (axial) end face of the polishing tool 100. Further, the polishing surface 130 may face in a direction away from the second axial end 102. The polishing surface 130 may have any shape or form. For example, the polishing surface 130 may be circular or oval when seen along the rotational axis RA1. However, these are only examples and not a complete enumeration.

[0074] Preferably, the polishing surface 130 may be formed by a polishing film 113 of the tool body 110. The polishing film 113 may form the first axial end 101. The polishing film 113 may be one of the layers of the tool body 110. For example, the polishing film 113 may be made of soft a material to avoid damaging the optical surface L1, L2 of the lens L in a polishing process. For instance, the polishing film 113 may be made of polyurethane. Naturally, other materials can be used for forming the polishing film 113. The polishing film 113 may be provided as a coating or a film. Preferably, the polishing film 113 may have a thickness ranging from 0.5 mm to 2.5 mm, or from 0.8 mm to 2.0 mm, or of 1.3 mm. The polishing film 113 may comprise a projecting edge 133 that protrudes radially from the tool body 110 as exemplarily illustrated in FIG. 9. Thereby, excessive operational forces when by entering the optical surface L1 in the polishing process can be avoided.

[0075] The second axial end 102 of the tool body 110 may preferably be formed by a base portion 111. The base portion 111 may be one of the layers of the tool body 110. The base portion 111 may be suitable (or configured) for rotatably supporting the polishing tool 100, for example, in a tool holder of a lens generator for a surface machining process. This is exemplarily indicated in the schematic illustration of FIG. 11. For this, the base portion 111 may be made of a preferably rigid material, such as metal or hard plastic, like nylon. However, this is only an example and it is conceivable to use other materials.

[0076] Preferably, the tool body 110 may also comprise a holder portion 112, which may be arranged between the polishing film 113 and the base portion 111. The holder portion 112 may be one of the layers of the tool body 110. The holder portion 112 may be capable of adapting axially to the contour of the optical surface L1, L2 of the lens L. For this, the holder portion 112 may be configured to be reversibly deformable under pressure. For example, the holder portion 112 may be made of plastic, e.g. a closed cell rubber material, such as neoprene, EPDM or NBR.

[0077] The tool body 110 further comprises a channel 140, which extends axially (along or coaxially with the rotational axis RA1) through the tool body 110. Therein, the channel 140 may penetrate the polishing film 113, the base portion 111 and the holder portion 112, respectively, as exemplarily illustrated in FIGS. 9 and 11. The channel 140 may have a constant, stepwise or continuously increasing/decreasing diameter along its extension direction. Preferably, the channel 140 may have a cross-section of any shape or form, for example a circular or rectangular cross-section. The channel 140 may be formed by the passages formed in the respective sections of the tool body 110 or it may be formed by providing a tube or hose extending through these passages. However, these are only examples and not a complete enumeration.

[0078] The channel 140 comprises an inlet 142, preferably for feeding a polishing agent into the channel 140. This is exemplarily illustrated in FIGS. 9 and 11. The inlet 142 is provided at the second axial end 102. Preferably, the base portion 111 may comprise the inlet 142. More preferred, the inlet 142 may be formed as an opening, for example in (the tool body 110 or) the base portion 111. The inlet 142 may have a cross-section with the same or a different shape as the channel 140. The channel 140 may expand radially towards or at the inlet 142. FIGS. 9 and 11 show this exemplarily.

[0079] The tool body 110 (or the base portion 111) may further comprise a port 143 for fluidly connecting the channel 140 with a polishing agent supply unit 240 (such as illustrated in FIG. 11). This is exemplarily illustrated in FIGS. 9 and 11. The port 143 may be a valve, hose connector, pipe or hose. Preferably, the port 143 may have the same size as the inlet 142. More preferred, the port 143 may be removeably connected to the inlet 142. The port 143 may be press-fitted into the inlet 142. Preferably, the port 143 may comprise a gasket 144 for radially sealing against the polishing agent supply unit 240 (cf. FIG. 11) to prevent the polishing agent from leaking and to enable only the polishing agent entering the channel 140 via the inlet 142. This is exemplarily shown in FIGS. 9 and 11. The gasket 144 may be made of rubber and/or may be an O-ring. However, these are only examples and not a complete enumeration.

[0080] The channel 140 further comprises an (preferably a single) outlet 141 to supply the polishing surface 130 with a polishing agent (preferably, the polishing agent fed through the inlet 142). The outlet 141 is provided at the first axial end 101. Preferably, the outlet 141 may be provided at the centre of the polishing surface 130 (such as exemplarily illustrated in FIGS. 9 to 11). Preferably, the outlet 141 may be coaxial with the rotational axis RA1. However, it is also conceivable to provide the outlet 141 at a different position. For example, the outlet 141 may be provided in a section immediately (e.g. radius<10 mm) surrounding the rotational axis RA1 (or the centre of the polishing surface 130). Preferably, the polishing film 113 may comprise the outlet 141. This is exemplarily illustrated in FIGS. 9 to 11. The outlet 141 may have any shape or form. For example, the outlet 141 may be circular, and/or may expand or reduce in diameter towards the first axial end 101. Preferably, the outlet 141 may be formed (to provide the same functionality) as a nozzle or throttle. The outlet 141 may have a diameter significantly smaller than the diameter of the polishing surface 130 (delimited by the perimeter), i.e. 1/100, 1/80, 1/50, 1/20, 1/10, ?, or ? of the diameter of the polishing surface 130.

[0081] The polishing agent may be a mixture between a liquid and solid particles, for example. The liquid may comprise water and/or a cooling agent. The solid particles may be made of metal (e.g. aluminium oxide), silicon or plastic. Preferably, the solid particles may have a grain size ranging from 1 to 2 micrometres.

[0082] The polishing surface 130 comprises at least one groove 150. Preferably, the polishing film 113 may comprise the groove 150. FIGS. 9 to 11 show this exemplarily.

[0083] As indicated exemplarily in FIG. 10, the polishing surface 130 may comprise a plurality of said grooves 150 (i.e. more than one of the groove 150). If in the following reference is made to the groove 150, the respective description also applies to the plurality of grooves 150 unless specified otherwise. The grooves 150 may have the same or a different configuration. For example, the grooves 150 may be identical or they may have at least partially a different shape and/or cross-section.

[0084] The groove 150 extends radially away from the outlet 141 to the perimeter of the polishing surface 130 to distribute the polishing agent across the polishing surface 130. The groove 150 may have any shape or form. For instance, the groove 150 may extend radially along a main extension direction. Therein, the groove 150 may extend such that its path does not turn back in a radial direction towards the outlet 141 (but instead, the groove 150 may proceed extending radially outwards). The groove 150 may extend in a linear, straight, curved and/or arcuate manner.

[0085] Alternatively or additionally, as exemplarily shown in FIG. 10, the groove 150 may extend in a wave or zigzag manner. Therein, the groove 150 may comprise different sections. The different sections may be connected to each other to form a continuous flow path for the polishing agent. Preferably, adjoining sections may be connected to each other by an arcuate portion. More preferred, the connecting portions, e.g. the arcuate portions, may form a gradual transition between the respective adjoining sections. Thereby, a continuous flow in the groove 150 can be achieved and blockages can be avoided. Preferably, the respective section (one of the different sections) may be straight, angled, arcuate and/or curved. Adjoining sections may extend circumferentially in opposite directions. An example for the different sections is provided in FIG. 10, where the groove 150 is exemplarily illustrated as comprising a straight first section 151 that connects the outlet 141 with a curved second section 152, and a third section 153 that extends straight from the curved second section 152 to the perimeter of the polishing surface 130 (polishing film 113). It is further conceivable that the groove 150 may have branches and/or may diverge into other (neighbouring) groove(s) 150.

[0086] The groove 150 may have a circular or rectangular cross-section when seen along the main extension direction and/or along a flow direction. Preferably, the groove 150 may have a width W ranging from 0.1 mm to 1.0 mm, or from 0.2 mm to 0.8 mm, or from 0.4 mm to 0.6 mm, or of 0.5 mm (cf. FIG. 10). Alternatively or additionally, the groove 150 may have a depth T ranging from 0.1 mm to 1.0 mm, or from 0.2 mm to 0.8 mm, or from 0.4 mm to 0.6 mm, or of 0.5 mm (cf. FIG. 9).

[0087] Different grooves 150 may preferably be provided on the polishing surface 130 as radially diverging. Alternatively or additionally, the plurality of grooves 150 may be (evenly) distributed about the outlet 141 (or the rotational axis RA1). For example, based on the arrangement and/or configuration of the grooves 150 (e.g. circumferential orientation, curved sections etc.), the polishing tool 100 may be used only in one rotational direction about the rotational axis RA1 in order to work properly.

[0088] A further aspect of the present invention relates to a system 200 for polishing of at least one of the optical surfaces L1, L2 of the spectacle lens L. FIG. 11 shows this exemplarily.

[0089] The system 200 comprises a surface processing unit 210 for processing the optical surface L1, L2 of the spectacle lens L. Therein, the surface processing unit 210 comprises the above described polishing tool 100. For example, it is also conceivable that the surface processing unit 210 may comprise a linearly movable (indicated by arrows 410, 420) cutter 400, such as illustrated exemplarily in FIG. 4.

[0090] The surface processing unit 210 comprises further a polishing agent supply unit 240 to supply the polishing surface 130 with a polishing agent. The polishing agent supply unit 240 is fluidly connected to the channel 140 (through the port 143) via the inlet 142 of the polishing tool 100 to supply the groove(s) 150 with polishing agent through the outlet 141. Preferably, the above described gasket 144 may radially seal the connection to prevent the polishing agent from leakage and to enable the polishing agent entering the channel 140 only via the inlet 142. Thus, for example, the polishing agent may be pumped by a pump 241 of the polishing agent supply unit 240 from a voluminous tank 242 of the polishing agent supply unit 240 through a pipe 213 to the port 143 and, subsequently, to the inlet 142. From the inlet 142, the polishing agent may flow through the channel 140 to the outlet 141 and to the groove(s) 150. For example, in the state of rotating the polishing tool 100 about the rotational axis RA1, the polishing agent is pushed radially outwards towards the perimeter of the polishing surface 130. Simultaneously existing circumferential forces may drive the polishing agent out of the grooves 150 so that the polishing agent is distributed across the (entire) polishing surface 130. The different configuration of the sections of the grooves 150 may cause the polishing agent to flow with different speeds. In particular, gradual transitions between adjoining sections may be useful for lowering the speed of flow of the polishing agent flowing through parts of the groove 150 that are radially further away from the outlet 141. Thus, effects of the centrifugal acceleration can be reduced.

[0091] The system 200 comprises further a lens support unit 220 (mentioned before in relation to FIGS. 3 to 6) for supporting the lens L during the polishing process. For this, the lens support unit 220 may comprise a lens holder 222 that may apply a suction force onto the lens L. Additionally, the lens support unit 220 may comprise a spindle 221 that rotates about a second rotational axis RA2 (indicated by arrow 223). FIGS. 3 to 6 and 11 show this exemplarily.

[0092] The system 200 comprises also a drive unit to apply a relative motion between the polishing tool 100 and the lens support unit 220. Therein, the relative motion comprises at least rotating the polishing tool 100 about the rotational axis RA1 to facilitate polishing of the optical surface L1, L2 with the polishing tool 100. This is exemplarily indicated by arrow 213 of FIG. 11. Additionally, the relative motion may comprise tilting, pivoting and/or linearly moving (as indicated by arrows 211 and 212 in FIG. 11) the polishing tool 100 relatively to the lens support unit 220 to apply the relative motion. Preferably, the drive unit may be adapted to displace the polishing tool 100 relative to the lens support unit 220 in order to obtain a defined distance therebetween.

[0093] It is also conceivable that the drive unit comprises and/or drives the spindle 221. Therein, the drive unit may be preferably adapted to rotate the lens support unit 220 about the second rotational axis RA2 to effect the (additional) relative motion (e.g. arrow 223). The drive unit may be part of the surface processing unit 210 or vice versa. FIG. 11 shows this exemplarily.

[0094] The system 200 may further comprise a control unit 230 for controlling the relative motion by the drive unit and/or the surface processing unit 210. The control unit 230 may control the system 200 based on processing features, like the lens type, form and thickness, the polishing tool type, the polishing agent type. Therein, the control unit 230 preferably may be configured to adapt a relative rotational speed between the optical surface L1, L2 and the polishing tool 100. Alternatively or additionally, the control unit 230 may be configured to adapt a pressure for supplying the polishing agent to the polishing tool 100 and/or a flow rate of the polishing agent (through the channel 140).

[0095] A further aspect of the present invention relates to a process of polishing at least one of the optical surfaces L1, L2 of the (spectacle) lens L. In the process, the above system 200 is provided. Alternatively, it is also conceivable to provide a different system for surface processing having the above described polishing tool 100.

[0096] The (spectacle) lens L is seated in said (or a) lens support unit 220. The polishing tool 100 is relatively rotated with respect to the lens L. A polishing agent is delivered through the channel 140 to the polishing surface 130, which faces an optical surface L1, L2 of the lens L to be polished. Through the rotation, for example, the polishing agent is delivered through the grooves 150 radially outwards from the outlet 141 so that the polishing agent is distributed across the polishing surface 130 for polishing the optical surface L1, L2.

[0097] For example, in a surface machining process, typically the lens L and the polishing tool 100 (with the polishing film 113) may be rotated relatively to each other in opposite directions from each other. By supplying polishing agent through the channel 140 into the grooves 150, the polishing agent can be transported (and squeezed) between the polishing surface 130 (the polishing film 113) and the optical surface L1, L2 of the lens L. Thereby, mechanical abrasion can be effected as the abrasive particles contained in the polishing agent can be moved due to the relative movement between the two surfaces (e.g. optical surface L1, L2/polishing surface 130). For example, it may be advantageous to provide a plurality of grooves 150 across the polishing surface 130 so that the polishing agent can be distributed uniformly. Generally, by directing/routing the polishing agent through the (pathway of the) grooves 150, it may be possible to control the exposure of the polishing agent to circumferential and radial acceleration (depending on its position in the groove 150). Thereby, the distribution of the polishing agent across the polishing surface 130 may be improved as it becomes possible to control how the polishing agent travels across the polishing surface 130 (i.e. where and when it travels with respect to being dispensed from the outlet 141).

[0098] The process may further comprise the step of controlling a thickness of a layer (film) of the polishing agent between the optical surface L1, L2 and the polishing surface 130 by adapting a flow rate and/or a supply pressure of the polishing agent based on a rotational speed of the polishing tool 100 and/or the spectacle lens L. However, it is also conceivable to consider (in addition) other parameters, such as the desired smoothness of the lens L or the consistency and composition of the polishing agent.

[0099] 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.

[0100] For example, it is also conceivable that the tool body 110 may comprise a plurality of channels 140 extending through the tool body 110. The plurality of channels 140 may connect one or more of the inlet 142 with one or more of the outlet 141. For example, each of the plurality of channels 140 may correspond with one inlet 142 and one outlet 141. However, each of the plurality of channels 140 may extend between the same inlet 142 and a plurality of outlets 142 that may be provided on the polishing surface 130. Each of the plurality of outlets 141 may be provided with one or more grooves 150 extending therefrom radially away to the perimeter of the polishing surface 130 to distribute the polishing agent across the polishing surface 130. For example, the plurality of outlets 141 may be distributed uniformly across the polishing surface 130. For instance, (larger) gaps between the grooves 150 as shown exemplarily in FIG. 10, may be provided with additional outlets 141 and additional grooves 150 (not illustrated).