Method and system for polishing a progressive surface of a lens

Abstract

The present invention relates to a method (100, 120) for polishing a progressive surface (12) of a lens (10), wherein the method (100, 120) comprises the following steps: holding (102), by a workpiece holder (42), the lens (10) in a first orientation (80); and polishing (104), by a polishing tool (52), the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (α), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70), in particular wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70). Further, the present invention relates to a system (40) for polishing a progressive surface (12) of a lens (10).

Description

Method and system for polishing a progressive surface of a lensBackground of the invention

[0001] The present invention relates to a method for polishing a progressive surface of a lens. Further, the present invention relates to a system for polishing a progressive surface of a lens.

[0002] In the industry, mechanical polishing of optical lenses, particularly those with progressive surfaces, polishing processes are used in the state of the art in which the optical surface of the lens is brought together with a polishing tool and subjected to a defined pressure. The polishing tool and the lens are each set in a rotational movement, while at the same time both parts perform an oscillating swivel movement in relation to each other that is adapted to the curvature of the lens surface. The rotational movementsof the lens and tool can be in the same or opposite direction, and the speeds of the two parts can be the same or different.

[0003] For instance, document US 2008 / 132157 A1 shows a block piece for holding an optical lens to be machined, with a coupling part for holding in a workpiece chuck and with a holding part for fastening the lens. The holding part has a convex or concave holding surface corresponding to a first side of the lens. The holding surface is, according to the shape of the lens to be held, provided in the form of a negative free- forming surface, and the block piece is made from a plastic that can be machined.

[0004] Further, document DE 10 2007 040395 A1 shows a method that involves clamping a lens blank at an outer end and pressing the blank in a standard ring. The blank is pressed against a rotating processing tool and is provided in the form of discs. Translatory relative movement between the tool and a lens upper surface of the blank in a plane perpendicular to a workpiece spindle are implemented. The spindle is controlled by a computer numerical controlled machine such that speed of the movement at surface elements of the surface is high corresponding to material removal to producing desired lens geometry. There is also disclosed a device for performing a single and multistrength spectacle lenses producing method, comprising a computer numerical controlled machine.

[0005] One objective during processing is to achieve homogeneous material removal on the optical surface. In order to meet this requirement, the integral of the relative speeds of the lens and polishing tool must be the same at every point on the optical surface at the end of the polishing process. This requirement can be largely met with this process if the speeds and swivel movement are set appropriately.

[0006] Another requirement for homogeneous material removal during processing is an even distribution of the polishing pressure on the optical surface of the lens. For spherical surfaces, for approximately rotationally symmetrical surfaces or for free-form surfaces with minor deviations from the spherical or rotationally symmetrical shape, this requirement can be approximately met by means of elastically acting tools. These tools,which are adapted to the average surface curvature of the lens and have an elastic surface, are subjected to a polishing pressure that is adapted to their size and hardness. As a result, the tool surface adapts to every part of the lens surface during the polishing process.

[0007] For instance, document DE 102013220973 A1 shows a tool for the polishing of an optical surface that has a base which has an active surface facing the optical surface. An intermediate layer is arranged on the active surface of the base. A polishing agent carrier is arranged on the elastic intermediate layer. The elastic intermediate layer projects radially beyond the active surface of the base and the polishing agent carrier projects radially beyond the elastic intermediate layer.

[0008] However, when polishing surfaces with greater deviations from rotational symmetry, such as progressive surfaces with medium and higher addition power effects, there are locally greater differences between tool and lens curvature. On the surface of the elastic tool, this leads to correspondingly greater differences in the deflection and compression rates. Zonally more compressed areas of the tool surface generate a higher pressure on the lens surface than those with lower compression, which makes the pressure distribution on the lens surface more or less inhomogeneous in such cases. A surface area in which the integral of the polishing pressure during the polishing process is lower than in its surroundings, for example in the area of a "trough", is polished less intensively due to the physical relationship between polishing pressure and material removal, which leads to less material removal at this point. In order to achieve the material removal necessary for the optical quality at this point, the entire lens surface must be polished for a correspondingly longer period of time.

[0009] Progressive surfaces are generally characterized by different optical effects and the associated different degrees of surface curvature above and below the horizontal lens axis. An exemplary depiction of a progressive lens is shown in Fig. 1.

[0010] The progressive surface of a spectacle lens can be located on its convex front side ("front-side progressive" or "FSP") or on its concave back side ("back-sideprogressive" or "BSP"). For example, in the case of a progressive surface attached to the back of a lens, the distance portion zone, which is located approximately in the middle above the horizontal lens axis, generally has a greater curvature than the near portion zone, which is located below the horizontal lens axis. Otherwise, in the case of a progressive surface attached to the front of the lens, the distance portion zone located above the horizontal lens axis has a weaker curvature than the near portion zone located below the horizontal lens axis. In general, the differences in the curvatures of the distance and near portion zones increase as the addition power effect increases.

[0011] The differences in curvature of the zones above and below the horizontal lens axis lead to different edge heights in these areas of progressive power lenses in a thickness direction of the lens. In the case of BSP surfaces, the local edge height in the near portion zone is always lower than that in the distance portion zone. During the polishing process, this area therefore experiences less compressive stress and therefore less material removal than, for example, the distance portion edge zone located on the opposite side of the horizontal lens axis.

[0012] In addition, the method of mathematical superimposition of progressive and toric effects frequently used in progressive lens designs results in the near portion edge zone geometrically representing a pronounced local " sink" in many progressive surfaces. During the polishing process, this situation then leads to worse polishability locally in the near portion edge zone due to the significantly lower compressive stress.

[0013] Another influencing factor is that the dynamic system of rotating lens and rotating polishing tool in the area of a highly deformed zone or a local " sink" on the lens surface does not always enable optimal adaptation of the tool to the local topography and thus a uniform distribution of the processing pressure. In addition, the radius of the swivel movement with which the tool is guided radially over the lens surface cannot be optimally adapted to a locally deformed zone due to the rotational movement of the lens, but only to an averaged curvature of the entire surface. The curvature of the tool surface is also adapted to the average surface shape of the lens, but not optimally to a local extreme area.

[0014] For these reasons, the polishing time for certain types of progressive surfaces with higher addition power may be two to three times longer than for a surface with low addition power. The long processing time inevitably leads to larger shape errors in the polished surface and therefore to reduced optical quality.

[0015] According to the current state of the art, surfaces of progressive lenses made of machinable materials are mainly generated using a turning process, in particular a high-speed cutting process. The surface of the finished lens always has a horizontally arranged tangent center plane in its center, i.e. a surface tangent perpendicular to the axis of rotation. This condition must be fulfilled as far as possible so that there is no unwanted penetration of the tool cutting edge and workpiece during the machining of the lens center and thus a corresponding geometry error in its center. This geometry error would increase with increasing tool radius and increasing deviations from the tangent plane. For this reason, the height differences between the edge zones of the distance and near portions of a progressive surface that interfere with the polishing process cannot be compensated during the generation process.Summary of the invention

[0016] Against this background, it is an object of the present invention to provide an improved method and system for polishing a progressive surface of a lens. In particular, it is an object to reduce the polishing time for polishing a progressive surface of a lens and to prevent a reduction of optical quality of the lens.

[0017] According to a first aspect of the invention, there is provided a method for polishing a progressive surface of a lens, wherein the method comprises the following steps: holding, by a workpiece holder, the lens in a first orientation; and polishing, by a polishing tool, the progressive surface of the lens while the lens is held by the workpiece holder in the first orientation,wherein, in the first orientation, the lens is tilted about a tilt axis by a tilt angle, wherein the tilt axis is perpendicular to a central symmetry axis, in particular wherein the progressive surface comprises a near portion edge zone and a distance portion edge zone, wherein, in the first orientation, the lens is tilted in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in a direction parallel to the central symmetry axis.

[0018] According to a second aspect of the invention, there is provided a system for polishing a progressive surface of a lens, wherein the system comprises: a workpiece holder that is configured to hold the lens in a first orientation; and a polishing tool that is configured to polish the progressive surface of the lens while the lens is held by the workpiece holder in the first orientation, wherein, in the first orientation, the lens is tilted about a tilt axis by a tilt angle, wherein the tilt axis is perpendicular to a central symmetry axis, in particular wherein the progressive surface comprises a near portion edge zone and a distance portion edge zone, wherein, in the first orientation, the lens is tilted in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in a direction parallel to the central symmetry axis.

[0019] The method of the first aspect may be conducted by the system of the second aspect.

[0020] The lens may also be called workpiece. Preferably, the lens may be a spectacle lens. The lens may be made of plastic or glass. The lens comprises a geometrical center. The geometrical center of the lens may be defined with respect to the boxing system according to EN ISO 13666. In particular, the geometrical center may be at the intersection of the horizontal and vertical centerlines of the shape of the lens.

[0021] The lens comprises a horizontal lens axis and a vertical lens axis. The horizontal lens axis and the vertical lens axis are perpendicular to each other. The horizontal lens axis and the vertical lens axis pass through the geometrical center of the lens. The lens further comprises a tangent center plane. The tangent center plane is defined, in particular spanned, by the horizontal lens axis and the vertical lens axis. The lens has a thickness direction that is perpendicular to tangent center plane. Thus, the horizontal les axis, the vertical lens axis and the thickness direction are mutually perpendicular to each other. The direction of the horizontal lens axis, the direction of the vertical lens axis and the thickness direction define a lens-fixed coordinate system.

[0022] The lens comprises a progressive surface. A lens comprising a progressive surface may be called progressive-power lens. The progressive surface is a surface that which is not rotationally symmetrical and has a continuous change of curvature over a part or whole of the surface. In particular, the progressive surface may be rotationally asymmetric with respect to the geometrical center. The progressive surface may be located on a front side of the lens or on a back side of the lens. In a preferred embodiment, the progressive surface is arranged at the back side of the lens. The front side may be a convex front side. The back side may be a concave back side.

[0023] The progressive surface comprises a distance portion zone and a near portion zone. The distance portion zone is arranged above the horizontal lens axis. The near portion zone is arranged below the horizontal lens axis. The lens comprises a distance portion edge zone and a near portion edge zone. The distance portion edge zone is a portion of the distance portion zone adjacent to the edge of lens. The near portion edge zone is a portion of the near portion zone adjacent to the edge of lens.

[0024] The curvature of the lens in the distance portion zone is different from the curvature of the lens in the near portion zone. Due to the differences in curvature, the distance portion edge zone and the near portion edge zone are at different heights in the thickness direction. The height difference in thickness direction between the distance portion edge zone and the near portion edge zone depends on various parameters, for an addition power of the lens, a toric component, and the like. The addition power of the lens describes a difference between the vertex power of the near portion and the vertex powerof the distance portion. In particular, the greater the addition, the greater is the height difference between the distance portion edge zone and the near portion edge zone.

[0025] The components of the system, in particular the workpiece holder and the polishing tool, are arranged with respect to a spatial coordinate system. The spatial coordinate system may have a vertical direction and two horizontal directions. Preferably, the polishing tool is arranged above the workpiece holder during the polishing of the progressive surface.

[0026] The workpiece holder is configured to hold, in particular to clamp, the lens. Preferably, the lens is blocked and the workpiece holder holds the blocked lens. In particular, the lens may be attached to a block piece with the progressive surface of the lens facing away from the block piece. The workpiece holder may be configured to hold or clamp the block piece. For holding the lens or the block piece, the workpiece holder may comprise some holding or clamping means for holding the lens or the blocked piece. The workpiece holder may be configured to rotate the lens about a rotation axis during the polishing process. The rotation axis passes through the geometrical center of the lens.

[0027] The polishing tool is a tool for polishing the lens. The polishing tool may comprise a base and a polishing element. The polishing element is attached to the base at a first side of the base. The base may be substantially rotationally symmetrical. The polishing element may be an elastic polishing element. The polishing element comprises a polishing surface for polishing the lens. During the polishing process, a polishing agent, such as Poly Pro All Format (Satisloh company), may be applied to the polishing surface.

[0028] The polishing tool may further comprise a mounting device for mounting the polishing tool to a machine or a machining robot. In particular, the mounting device may comprise a receptacle for a corresponding holder of the machine or machining robot. The mounting device may be attached to the base or formed by the base, preferably at a second side of the base opposite to the first side of the base. The machine or a machining robot may be part of the system of the second aspect. In particular, the polishing tool may be configured as described in DE 10 2013220 973 A1.

[0029] The machine or machining robot may be configured to move and / or rotate the polishing tool during the polishing process. In particular, the machine or machining robot may rotate the polishing tool about a rotational symmetry axis of the base and / or may perform a, preferably oscillating, swivel motion of the polishing tool with respect to a central axis and / or may perform a rotational motion of polishing tool about the central axis.

[0030] For polishing the progressive surface of the lens, the workpiece holder holds the lens and the polishing tool polishes the lens. This polishing process is conducted with respect to the central symmetry axis. The central symmetry axis is a symmetry axis of an arrangement and / or a motion of the workpiece holder and / or the polishing tool during the polishing process. The central symmetry axis passes through the geometrical center of the lens when the lens is held by the workpiece holder. Preferably, the central symmetry axis may be parallel to a vertical direction of the spatial coordinate system.

[0031] For instance, in the polishing process, the polishing surface of the polishing tool may be brought into contact with the progressive surface of the lens and the polishing tool and / or the workpiece holder may perform one or more motions with respect to the central symmetry axis. In particular, the one or more motions may comprise the rotational motion of the workpiece holder for rotating the lens and / or the swivel motion of the polishing tool and / or the rotational motion of the polishing tool.

[0032] In polishing processes in the state of the art, a lens was always held in such a way that its tangent center plan was perpendicular to its central symmetry axis. In particular, the tangent center plane was horizontally arranged in the spatial coordinate system during the polishing process. Therefore, for lenses with progressive surfaces, the near portion edge zone and the distance portion edge zone were arranged at different heights in a direction parallel to the central symmetry axis.

[0033] According to the aspects of the present invention, the lens is held by the workpiece holder in the first orientation during the polishing process, wherein, in the first orientation, the lens is tilted about the tilt axis by the tilt angle. The tilt axis is perpendicular to the central symmetry axis. The tilt axis may pass through the geometrical center of thelens. In particular, in the first orientation, the tangent center plane of the lens may be tilted about the tilt axis by the tilt angle. Thus, the lens can be tilted such that the the tangent center plane of the lens is not perpendicular to the central symmetry axis.

[0034] By this, the lens can be tilted in order to compensate the height difference between the near portion edge zone and the distance portion edge zone in the direction parallel to the central symmetry axis. In particular, the lens can be tilted in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in the direction parallel to the central symmetry axis. With other words, the tilt axis and the tilt angle may be set or calculated in such a way that the lens is tilted so that the near portion edge zone and the distance portion edge zone are substantially at the same height in the direction parallel to the central symmetry axis.

[0035] In general, progressive surfaces of lenses usually have at least two components that are important for the optical effect: an addition power resulting in a freeform progressive surface with a distance portion and a near portion with an addition power, individually tailored to the needs of the spectacle wearer; and a mathematically superimposed toric component, adapted to the individual needs of the spectacle wearer, in particular to the astigmatism, the effect of which can be between 0.00 and approximately 6.00 diopters and have an axial position between 0° and 180°. By mathematically combining these two components, i.e. the addition power and the toric component, a variety of different surface designs for progressive surfaces of lenses are possible, which are calculated using special algorithms.

[0036] In general, the height difference between the distance portion edge zone and the near portion edge zone increases as the addition power of the progressive surface increases. However, due to the influence of the toric component, there is a certain spread for each individual addition power. Table 1 below shows the height difference between the two edge zones and the necessary tilt angle for optimally compensating the height difference for several examples of progressive surfaces of lenses with different addition powers and toric components. In these examples, the diameter of the lenses is 70 mm.Table 1

[0037] By tilting the lens in such a way that the height difference between the near portion edge zone and the distance portion edge zone is reduced in the direction parallel to the central symmetry axis, the polishing process of the lens is improved. In particular, by tilting the lens in such a way that the near portion edge zone and the distance portion edge zone are at the same height in the direction parallel to the central symmetry axis as in the examples of Table 1, the height difference is optimally compensated and the polishing process of the lens is significantly improved.

[0038] Therefore, by the aspects of the present invention, the progressive surface of the lens can be polished more evenly by the polishing tool. In particular, polishability of progressive-power lenses, especially those with a higher addition effect, can beimproved compared with known polishing methods in the state of the art. Further, the polishing time can be reduced by up to 50%, depending on the surface design, and therefore efficiency could be increased and a higher throughput could be achieved when processing the lenses. By the reduced polishing time, the number of polished lenses per polishing tool can also be increased. Further, the shorter polishing time and the associated reduction in the polishing error leads to an improvement in the optical quality of the glass. As with the polishing time, an improvement of up to 50% can be achieved. Further, the dynamic situation during the polishing process can also be improved because the necessary deflections of the workpiece holder and the polishing tool are reduced. This enables higher speeds of the motions of the workpiece holder and the polishing tool and thus greater efficiency. In extreme cases, the polishing process can be used to polish lens designs that cannot be polishes using conventional polishing technologies. Therefore, the aspects of the present invention provide an improved method and system for polishing the progressive surface of a lens.

[0039] Accordingly, the objective technical problem is fully solved.

[0040] In a preferred refinement of any one of the above aspects, the method may further comprise the following step: processing, by a processing tool, the lens for establishing or adapting the progressive surface of the lens while the lens is held by the workpiece holder in the first orientation.

[0041] The processing step may be performed before the polishing step. For instance, in the processing step, the processing tool may grind or cut the lens for establishing or adapting the progressive surface of the lens. In particular, the processing tool may be a grinding or cutting tool. Processing the lens in the same tilted orientation as in the polishing process could be beneficial for the manufacturing of lenses made of glass.

[0042] In a further refinement of any one of the above aspects, the method may further comprise the following steps:holding, by the workpiece holder, the lens in a second orientation different from the first orientation; and processing, by a processing tool, the lens for establishing or adapting the progressive surface of the lens while the lens is held by the workpiece holder in the second orientation.

[0043] In the second orientation, the lens may be not tilted about the tilt axis. In particular, in the second orientation, the tangent center plane of the lens is not tilted about the tilt axis. For instance, in the second orientation, the tangent center plane of the lens may be arranged perpendicular to the center symmetry axis. The steps of holding the lens in the second orientation and processing the lens may be performed before the steps of holding the lens in the first orientation and polishing the progressive surface of the lens. Processing the lens in another orientation as in the polishing process, in particular in an orientation in that the tangent center plane is perpendicular to the center symmetry axis, may be used for the manufacturing of lenses made of plastic material.

[0044] In a further refinement of any one of the above aspects, the workpiece holder may comprise a workpiece spindle for rotating the lens about a rotation axis, wherein the central symmetry axis is the rotation axis of the workpiece spindle.

[0045] With other words, the center symmetry axis coincides with the rotation axis of the workpiece spindle. The rotation axis of the workpiece spindle passes through geometrical center of the lens. In particular, the workpiece spindle rotates the lens about the rotation axis during the step of polishing. The workpiece spindle may also rotate the lens about the rotation axis during the step of processing.

[0046] In a further refinement of any one of the above aspects, the tilt axis may coincide with a horizontal lens axis of the lens.

[0047] With other words, the tilt axis is the horizontal lens axis. The horizontal lens axis is arranged between the near portion zone and the distance portion zone. Bytilting the lens about the horizontal lens axis, the heights of the near portion edge zone and the distance portion edge zone in the direction parallel to the center symmetry axis could be substantially equalized. In particular, the tilt axis that allows optimum height compensation is near the horizontal lens axis. Thus, by using or setting the horizontal lens axis as the tilt axis, a good height compensation can still be achieved in a simple manner.

[0048] In a further refinement of any one of the above aspects, the tilt angle may be 0.5° to 3°, preferable 1.0° to 2.5°, in particular 2.0°.

[0049] In particular, the tilt angle may be a predefined tilt angle that is set or calculated in advance. The addition power of progressive-power lenses is usually between 1.00 dpt and 3.50 dpt. In particular, the average addition power is about 2.50 dpt. In most cases, the necessary tilt angle to compensate the height difference between the near portion edge zone and the distance portion edge zone of such progressive-power lenses is between 0.5° and 3°. On average, a tilt angle of 2° is the best choice. In particular, for progressive-power lenses with the average addition power, a tilt angle of 2° allows an optimum height compensation. For progressive-power lenses with low addition power, a tilt angle of 2° results in a certain overcompensation of the height correction in the edge area of the near part. For progressive-power lenses with very high addition, the height correction achieved by a tilt angle of 2° is slightly too low. As a result, the polishing problems caused by large differences in the edge heights of the distance and near portion zones can be eliminated in all cases.

[0050] In a further refinement of any one of the above aspects, the method may further comprise the following step: calculating first orientation based on lens parameters of the progressive surface of the lens.

[0051] By this, the first orientation can be calculated in order to achieve an optimal height compensation. Thereby, the polishing process is further improved. In particular, a control device may calculate the first orientation based on lens parameters of theprogressive surface of the lens. The control unit may be part of the system. The lens parameters may be surface data relating to the progressive surface. In particular, the lens parameters may comprise a diameter of the lens and a height difference between the distance portion edge zone and the near portion edge zone in the thickness-direction of the lens. Additionally or alternatively, the lens parameters may comprise a first location of a maximum height at the near portion edge zone and a second location of a minimum height at the distance portion edge zone. The first location and the second location may be defined in the lens-fixed coordinate system. The lens parameters may be given in advance. Alternatively, the lens parameters may be measured or calculated in advance.

[0052] In particular, first orientation is calculated in such a way that the near portion edge zone and the distance portion edge zone are at the same height in a direction parallel to the central symmetry axis. In particular, for calculating the first orientation, the tilt angle and / or the tilt axis may be calculated based on the lens parameters. For instance, the tilt angle and the tilt axis may be calculated. Alternatively, only the tilt angle may be calculated, while a fixed tilt axis is used. The fixed tilt axis may be the horizontal lens axis. Alternatively, only the tilt axis may be calculated, while a fixed tilt angle is used. The fixed tilt angle may be 0.5° to 3°, preferable 1.0° to 2.5°, in particular 2.0°.

[0053] For instance, the tilt axis may be calculated based on the first location and the second location. In particular, the tilt axis may be axis between the first location and the second location, wherein the first location and the second location are arranged symmetric to this axis. The tilt angle may be calculated based on the diameter of the lens and the height difference between the distance portion edge zone and the near portion edge zone in the thickness-direction of the lens. In particular, the tilt angle may be calculated according to the following formula:(1) tan aln formula (1), a is the tilt angle, d is the diameter of the lens, and Ah is the height difference.

[0054] In a further refinement of any one of the above aspects, the workpiece holder may comprise a workpiece chuck for holding, in particular clamping or blocking, the lens, wherein the workpiece chuck is configured to hold the lens in the first orientation.

[0055] In particular, the workpiece chuck may be configured to hold, in particular to clamp, the lens or the block piece in such a way that the lens is hold in the first orientation. For this, the workpiece chuck may be formed or design to hold, in particular to clamp, the lens or the block piece in a specific orientation. In the state of the art, a workpiece chuck usually has a flat surface on both its upper and lower sides that are arranged perpendicular to the central symmetry axis. For holding the lens in the first orientation, the workpiece chuck may now be designed in such a way that its upper flat surface is tilted by the tilt angle, preferably about 2°. By this, the lens can be easily held in the first orientation. The workpiece spindle may support the workpiece chuck. In particular, the workpiece chuck may be mounted or attached to the workpiece spindle. The workpiece spindle may be configured to rotate the workpiece chuck about the rotation axis. When the lens is held by the workpiece chuck, the lens is rotated together with the workpiece chuck about the rotation axis.

[0056] In a further refinement of any one of the above aspects, the workpiece holder may comprise an adjusting device, wherein the adjusting device adjusts an orientation of the lens with respect to the central symmetry axis, in particular for arranging the lens in the first orientation.

[0057] For instance, the adjusting device is configured to adjust the orientation of the lens when the lens is held by the workpiece holder, in particular by the workpiece chuck. For this, the adjusting device may be configured to adjust an orientation of the workpiece chuck. The adjusting device may be arranged, in particular mounted, between the workpiece spindle and the workpiece chuck. For instance, when the lens is held by the workpiece holder, the adjusting device can adjust the orientation of the lens so that the lens is hold in the first orientation or in the second orientation. In particular, the adjusting device may be configured to adjust the tilt axis and / or the tilt angle for arranging the lens in the first orientation or in the second orientation. The adjusting device may be configured to adjust the orientation of the lens according to the calculated first orientation, in particu-lar the calculated tilt axis and / or the calculated tilt angle. In particular, the adjusting device may be controlled by the control device. By this, the orientation for optimal height compensation during the polishing process can be individually adjusted for each lens. Thereby, the polishing process is further improved.

[0058] In a further refinement of any one of the above aspects, the method may further comprise the following steps: aligning, by an aligning device, the lens with respect to a reference direction, in particular in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in the reference direction; and inserting, by a handling device, the aligned lens into a workpiece chuck of the workpiece holder in the first orientation based on a relationship between the reference direction and the central symmetry axis.

[0059] In particular, the aligning device may align the blocked lens respect to a reference direction. The aligning device may be a separate positioning / referencing station by which the necessary tilt of the progressive surfaces of lens can be set before the lens is inserted into the workpiece holder in the first orientation. For aligning the lens, the lens may be placed with the side of the lens comprising the progressive surface on the aligning device. In particular, the aligning device may comprise three support elements on which the lens can be placed. The three support elements serve as support or contact points for supporting the progressive surface of the lens. Preferably, one of the support elements may contact the progressive surface of the lens above horizontal lens axis, i.e. in the distance portion zone, and the other two support elements may contact the progressive surface of the lens below the horizontal lens axis, i.e. in the near portion zone. The aligning device is configured to align the lens with respect to a reference direction such that the near portion edge zone and the distance portion edge zone are substantially at the same height in the reference direction. For instance, the aligning device may comprise an adjusting mechanism for adjusting an orientation of the lens with respect to the refer-ence direction. In particular, at least one of the support elements may be, preferably electrically, movable in the reference direction in order to adjust the orientation of the lens with respect to the reference direction. The aligning device may be controlled by the control device. In particular, the aligning device align the lens in accordance with the calculated first orientation.

[0060] The handling device is configured to insert the aligned lens into the workpiece chuck of the workpiece holder. For instance, the handling device may be a handling robot, in particular comprising a gripping device, that may be configured to pick, transfer and drop the lens, in particular the blocked lens. In particular, the handling device may pick the aligned lens from the aligning device, transfer the aligned lens to the workpiece holder and insert the aligned lens into the workpiece chuck. Based on the relationship between the reference direction and the central symmetry axis, the handling device can insert the aligned lens into the workpiece chuck in the first orientation. Preferably, the reference direction is parallel to the central symmetry axis. In this case the handling device may turn the aligned lens, in particular about 180°, before inserting the aligned lens into the workpiece chuck. In particular, the reference direction and the central symmetry axis may be parallel to a vertical direction of the spatial coordinate system. The handling device may be controlled by the control device. By this, the lens can be easily provided in the first orientation for height compensation between the distance portion edge zone and the near portion edge zone. Thereby, the polishing process is further improved.

[0061] In a further refinement of any one of the above aspects, the workpiece holder may comprise an adjusting device, wherein the adjusting device is configured to adjust an orientation of the lens with respect to the central symmetry axis, in particular for arranging the lens in the first orientation.

[0062] By this, the orientation for optimal height compensation during the polishing process can be individually adjusted for each lens. Thereby, the polishing process is further improved.

[0063] In a further refinement of any one of the above aspects, the system may further comprise an aligning device and a handling device, wherein the aligning device is configured to align the lens with respect to a reference direction, in particular in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in the reference direction, and, wherein the handling device is configured to insert the aligned lens into a workpiece chuck of the workpiece holder in the first orientation based on a relationship between the reference direction and the central symmetry axis.

[0064] By this, the lens can be easily provided in the first orientation for height compensation between the distance portion edge zone and the near portion edge zone. Thereby, the polishing process is further improved.

[0065] In a further refinement of any one of the above aspects, wherein the system may further comprise a control device that is configured to: calculate the first orientation based on lens parameters of the progressive surface of the lens; and control the adjusting device to adjust an orientation of the lens with respect to the central symmetry axis, in particular for arranging the lens in the first orientation.

[0066] In particular, the control device can calculate the first orientation and adjust the lens orientation in the workpiece holder as already explained above. By this, the orientation for optimal height compensation during the polishing process can be individually calculated and adjusted for each lens. Thereby, the polishing process is further improved.

[0067] In a further refinement of any one of the above aspects, wherein the system comprises a control device that is configured to:calculate the first orientation based on lens parameters of the progressive surface of the lens; control the alignment device to align the lens with respect to a reference direction, in particular in such a way that the near portion edge zone and the distance portion edge zone are substantially at the same height in the reference direction; and control the handling device to insert the aligned lens into a workpiece chuck of the workpiece holder in the first orientation based on a relationship between the reference direction and the central symmetry axis.

[0068] In particular, the control device can calculate the first orientation and align and insert the lens as already explained above. By this, the lens can be easily provided in the first orientation for height compensation between the distance portion edge zone and the near portion edge zone. Thereby, the polishing process is further improved.

[0069] It goes without saying that the features mentioned above and those yet to be explained below cannot only be used in the respective combinations disclosed, but also in different combinations or alone without departing from the scope of the present invention.Brief description of the drawings

[0070] Further features and advantages will be apparent from the following detailed description. Unless otherwise defined, all technical and scientific terms have the meaning as commonly understood by one of ordinary skill in the art. In the drawings:Fig. 1 shows a simplified schematic illustration of a lens comprising a progressive surface;Fig. 2 shows a simplified schematic illustration of an exemplary embodiment of a system for polishing a progressive surface of a lens;Fig. 3 shows schematic illustration of a lens in a first orientation; andFig. 4 shows schematic illustration of a lens in a second orientation;Fig. 5 shows a schematic illustration of a first exemplary embodiment of a method for polishing a progressive surface of a lens; andFig. 6 shows a schematic illustration of a second exemplary embodiment of a method for polishing a progressive surface of a lens.Detailed description of the drawings

[0071] In Fig. 1, a lens 10 is shown in two views (A) and (B). The lens 10 is a progressive-power lens. The lens comprises a progressive surface 12. The view (A) of Fig. 1 , is a plan view of the progressive surface 12 of the lens 10. The view (B) of Fig. 1 is a cross sectional view of the lens 10.

[0072] The lens 10 has a front side 30 and a back side 32. The progressive surface 12 is located at the back side 32 of the lens 10. The lens 10 comprises a horizontal lens axis 14 and a vertical lens axis 16. The front side 30 and the back side 32 are spaced apart from each other in a thickness direction 18 of the lens 10. The horizontal length axis 14, the vertical length axis 16 and the thickness direction 18 are mutually perpendicular to each other.

[0073] The lens 10 comprises a geometrical center 20. The horizontal lens axis 14 and a vertical lens axis 16 pass through the geometrical center 20. The lens 10 comprises a tangent center plane 34. The tangent center plane 34 is defined, in particular spanned, by the horizontal lens axis 14 and the vertical lens axis 16. The tangent center plane 34 passes through the geometrical center 20 of the lens 10.

[0074] The progressive surface 12 comprise a distance portion zone 22 and a near portion zone 24. The distance portion zone 22 is arranged above the horizontal lens axis 14. The near portion zone 24 is arranged below the horizontal lens axis 14. The lens 10 further comprises a distance portion edge zone 26 and a near portion edge zone 28. The distance portion edge zone 26 is a portion of the distance portion zone 22 adjacent to the edge of lens 10. The near portion edge zone 28 is a portion of the near portion zone 24 adjacent to the edge of lens 10.

[0075] In Fig. 2, an exemplary embodiment of a system 40 for polishing the progressive surface 14 of the lens 12 is shown.

[0076] The system 40 comprises a workpiece holder 42. The workpiece holder 42 is configured to hold, in particular to clamp, the lens 10. Preferably, the lens 10 is blocked and the workpiece holder 42 can hold the blocked lens 10. In particular, the lens 10 may be attached to a block piece and the workpiece holder 42 can hold or clamp the block piece. The workpiece holder 42 comprise a workpiece chuck 44 for holding, in particular clamping, the lens 10, in particular the blocked lens 10. The workpiece holder 42 comprises a workpiece spindle 46 for rotating the lens 10 about a rotation axis. The workpiece spindle 46 supports the workpiece chuck 44. The workpiece chuck 44 is mounted or attached to the workpiece spindle 46. The workpiece spindle 46 is configured to rotate the workpiece chuck 44 about the rotation axis. When the lens 10 is held by the workpiece chuck 44, the lens 10 is rotated together with the workpiece chuck 44 about the rotation axis. The rotation axis of the workpiece spindle 46 passes through geometrical center 20 of the lens 10 when the lens 10 is held in the workpiece chuck 44. A rotational motion of the lens 10 and the workpiece chuck 44 about the rotation axis is indicated with the reference number 48. During polishing process, the workpiece spindle 46 rotates the lens 10 about the rotation axis.

[0077] The workpiece holder 42 may optionally comprise an adjusting device 50. The adjusting device 50 is configured to adjust an orientation of the lens 10 when the lens 10 is held by the workpiece holder 42, in particular by the workpiece chuck 44. For this, the adjusting device 50 is configured to adjust an orientation of the workpiece chuck44. The adjusting device 50 is arranged, in particular mounted, between the workpiece spindle 46 and the workpiece chuck 44.

[0078] The system 40 further comprises a polishing tool 52. The polishing tool 52 is a tool for polishing the lens 10, in particular for polishing the progressive surface 12 of the lens 10. For polishing the lens 10, the polishing tool comprises a polishing element 54. The polishing tool may be configured as described in DE 102013 220973 A1.

[0079] The system 40 may optionally comprise a processing tool 56 for processing the lens 10 for establishing or adapting the progressive surface 12 of the lens 10. The processing tool 56 may be a grinding or cutting tool that is configured to grind or cut the lens 10.

[0080] The system 40 further comprises a machine or machining robot 58. The polishing tool 52 is mounted to the machine or machining robot 58. The machine or machining robot 58 is configured to move and / or rotate the polishing tool 52 during the polishing process. In particular, the machine or machining robot 58 is configured to perform a, preferably oscillating, swivel motion of the polishing tool 60 during the polishing process. The processing tool 56 may also be mounted to the machine or machining robot 58. The machine or machining robot 58 may be configured to move and / or rotate the polishing tool 52 for processing the lens 10.

[0081] The system 40 further comprises an aligning device 62. The aligning device 62 is configured to align the lens 10 with respect to a reference direction. In particular, the aligning device 62 may align the blocked lens 10 respect to a reference direction. The aligning device 62 comprises three support elements 64 on which the lens 10 can be placed with the side of the lens 10 comprising the progressive surface 12. The aligning device 62 may comprise an adjusting mechanism for adjusting an orientation of the lens 10 with respect to the reference direction. In particular, at least one of the support elements 62 may be, preferably electrically, movable in the reference direction in order to adjust the orientation of the lens 10 with respect to the reference direction.

[0082] The system 40 further comprises a handling device 66. The handling device 66 may be a handling robot. The handling device 66 is configured to pick, transfer and drop the lens 10, in particular the blocked lens 10. In particular, the handling device 66 is configured to insert the aligned lens 10 into the workpiece chuck 44.

[0083] The system 40 further comprises a control device 68. The control device 68 can perform calculations and control operations in the system 40. For instance, the control device 68 may control the operations of the workpiece holder 42, in particular the adjusting device 50 thereof, the polishing tool 52, the processing tool 56, the machine or machining robot 58, the alignment device 62, in particular the adjusting mechanism thereof, and / or the handling device 66. For performing these control operations, the control device 68 may be connected to respective components of the system 40, in particular to transmit respective control signals for controlling the respective components. In particular, the control device 68 may comprise a control unit for performing the control operations. Further, the control device 68 may comprise a calculation unit for performing the calculations. In particular, the control device 68 may calculate the first orientation of the lens 10.

[0084] The control device 68 may be connected to or may comprise a non- transitory data memory where a computer program is stored. In some exemplary embodiments, the control device 68 is a general-purpose computer, such as a commercially available personal computer operating under Windows®, Linux or MacOS and the computer program from memory comprise program code designed and configured for performing the calculations and control operations in the system 40. In an alternative exemplary embodiment, the control device 68 is logical circuit, such as a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a microcontroller, or any other appropriate programmable electrical circuit. Therein, the calculations and control operations can be implemented within the logical circuit so that the logical circuit is designed and configured for this purpose. For implementing the calculations and control operations in the logical circuit any appropriate programming language or hardware description language can be used, such as C, VHDL, and the like.

[0085] For polishing the progressive surface 12 of the lens 10, the workpiece holder 42 holds the lens 10 and the polishing tool 52 polishes the lens 10. This polishing process is conducted with respect to a central symmetry axis 70. The central symmetry axis 70 passes through the geometrical center 20 of the lens 10 when the lens 10 is held in the workpiece holder 42. The rotation axis of the workpiece spindle 46 and / or a symmetry axis of the swivel motion 60 coincide with the central symmetry axis 70. In particular, the central symmetry axis 70 is the rotation axis of the workpiece spindle 46. During the polishing process, the workpiece spindle 46 rotates the lens 10 about the rotation axis and the polishing tool 52 comes into contact with the progressive surface 12 of the lens 10 and performs the swivel motion 60.

[0086] During the polishing process by the polishing tool 52, the workpiece holder 42 is configured to hold the lens 10 in a first orientation. Fig. 3 shows the arrangement of the lens 10 in the first orientation with respect to the central symmetry axis 70. The first orientation 80 is denoted with the reference numeral 84.

[0087] In the first orientation 80, the lens 10, in particular the tangent center plane 34 of the lens 10, is tilted about a tilt axis 82 by a tilt angle a. The tilt axis 82 is perpendicular to the central symmetry axis 70. The tilt axis 82 passes through the geometrical center 20 of the lens 10. In the first orientation 80, the lens 10 is tilted in such a way that the near portion edge zone 24 and the distance portion edge zone 22 are substantially at the same height 84 in a direction parallel to the central symmetry axis 70. When the tilt angle a is zero, the tangent center plane 34 is arranged perpendicular to the central symmetry axis 70.

[0088] The first orientation 80, in particular the tilt axis 82 and the tilt angle a, may be fixed or set in advance to predefined values. Alternatively, the first orientation 80, in particular at least the tilt axis 82 and / or the tilt angle a, may calculated by the control device 68.

[0089] In a first example, the tilt axis 82 and the tilt angle a are fixed to predefined values. In particular, the tilt axis 82 may coincide with the horizontal lens axis 14 and the tilt angle a may be 0.5° to 3°, preferable 1.0° to 2.5°, in particular 2.0°.

[0090] In a second example, the tilt axis 82 is fixed, preferably to coincide with the horizontal lens axis 14, and the tilt angle a is calculated by the control device 68 based on lens parameters of the progressive surface 12 of the lens 10.

[0091] In a third example, the tilt angle a is fixed to an angle of 0.5° to 3°, preferable 1.0° to 2.5°, in particular 2.0°, and the tilt axis 82 is calculated by the control device 68 based on lens parameters of the progressive surface 12 of the lens 10.

[0092] In a fourth example, the tilt axis 82 and the tilt angle a are calculated by the control device 68 based on lens parameters of the progressive surface 12 of the lens 10.

[0093] For providing the lens 10 in the first orientation 80, a specific design of the workpiece chuck 44 and / or the adjusting device 50 and / or the alignment device 62 may be used.

[0094] For instance, the workpiece chuck 44 may be configured to hold the lens, in particular the blocked lens 10, in the first orientation 80. For this, the workpiece chuck 44 may be formed or design to hold, in particular to clamp, the lens or the block piece in a specific orientation. This configuration of the workpiece chuck 44 may be used in the first example.

[0095] Alternatively, the adjusting device 50 may be used to adjust the orientation of the lens 10 to the first orientation 80 when the lens 10 is held by the workpiece chuck 44. In particular, the control device 68 may control the adjusting device 50 to adjust the orientation of the lens 10 to the first orientation 80. The adjusting device 50 may be used in this way in any of the second example, the third example and the fourth example.

[0096] Alternatively, the alignment device 62 and the handling device 66 may be used to align the lens 80 with respect to a reference direction, in particular in such a way that the near portion edge zone 28 and the distance portion edge zone 26 are substantially at the same height in the reference direction, and to insert the aligned lens 80 into the workpiece chuck 44 in the first orientation 80 based on a relationship between the reference direction and the central symmetry axis 70. In particular, the control device 68 may control the alignment device 62 to align the lens with respect to the reference direction, and may control the handling device 66 to insert the aligned lens 80 into the workpiece chuck 44 in the first orientation 80 based on a relationship between the reference direction and the central symmetry axis 70. The alignment device 62 and the handling device 66 may be used may be used in this way in any of the second example, the third example and the fourth example.

[0097] Before polishing the lens 10, the lens 10 may be processed by the processing tool 56. During the processing by the processing tool 56, the workpiece holder 42 is configured to hold the lens 10 in the first orientation 80 or in a second orientation. Fig. 4 shows the arrangement of the lens 10 in the second orientation with respect to the central symmetry axis 70. The second orientation is denoted with the reference numeral 86.

[0098] In the second orientation 86, the lens 10, in particular the tangent center plane 34 of the lens 10, is not tilted about the tilt axis 82. In the second orientation 86, the lens 10, in particular the tangent center plane 34 of the lens 10, is arranged perpendicular to the center symmetry axis 70. In the second orientation 86, the near portion edge zone 24 and the distance portion edge zone 22 are arranged at different heights in the direction parallel to the central symmetry axis 70. A height difference between the near portion edge zone 24 and the distance portion edge zone 22 in the direction parallel to the central symmetry axis 70 is denoted with the reference number 88.

[0099] In Fig. 5, a first exemplary embodiment of a method 100 for polishing the progressive surface 12 of the lens 10 is shown. The method 100 may be conducted by the system 40.

[0100] In a step 102 of the method 100, the lens 10 is held by the workpiece holder 42 in the first orientation 80. In the first orientation, the lens 10 is tilted about the tilt axis 82 by the tilt angle a, wherein the tilt axis 82 is perpendicular to a central symmetry axis 70, in particular wherein, in the first orientation 80, the lens 10 is tilted in such a way that the near portion edge zone 28 and the distance portion edge zone 26 are substantially at the same height in a direction parallel to the central symmetry axis 70. The workpiece chuck 44 of the workpiece holder 42 may be configured, in particular formed or designed, to hold the lens in the first orientation 80. Alternatively, the adjusting device 50 may adjust, in particular under the control of the control device 68, an orientation of the lens 10 with respect to the symmetry axis 70, in particular for arranging the lens 10 in the first orientation 80.

[0101] In a further step 104 of the method 100, the progressive surface 12 of the lens 10 is polished by the polishing tool 52 while the lens 10 is held by the workpiece holder 42 in the first orientation 80.

[0102] In an optional step 106 of the method 100, the lens 10 is processed by a processing tool 56 for establishing or adapting the progressive surface 12 of the lens 10 while the lens 10 is held by the workpiece holder 42 in the first orientation 80. The step 106 is performed before the step 104.

[0103] In an optional step 108 of the method 100, the first orientation 80 is calculated, preferably by the control device 68, based on lens parameters of the progressive surface 12 of the lens 10. In the steps 104 and 106, the workpiece holder 42 may hold the lens in the calculated first orientation 80.

[0104] In an optional step 110 of the method 100, the lens 10 is aligned by the aligning device 62 with respect to a reference direction, in particular in such a way that the near portion edge zone 28 and the distance portion edge zone 26 are substantially at the same height in the reference direction. The aligning device 62 may align the lens 10 in accordance with the calculated first orientation 80. In particular, the aligning device 62may be controlled by the control device 68 to align the lens 10 with respect to a reference direction.

[0105] In an optional step 112 of the method 100, the aligned lens 10 is inserted by the handling device 66 into the workpiece chuck 44 of the workpiece holder 42 in the first orientation 80 based on a relationship between the reference direction and the central symmetry axis 70. In particular, the handling device 66 may be controlled by the control device 68 to insert the aligned lens 10 into the workpiece chuck 44 in the first orientation 80.

[0106] In Fig. 6, a second embodiment of a method 120 for polishing the progressive surface 12 of the lens 10 is shown. The method 120 may be conducted by the system 40. The configuration of the method 120 is substantially the same as the configuration of the method 100. The same elements are designated with the same reference numerals and are not described in more detail. In particular, the method 120 comprises the steps 102, 104, 108, 110 112 of the method 100. However, the method 120 does not comprise the step 106 of the method 100. Instead, the method 120 additionally comprises steps 122 and 124.

[0107] In the step 122 of the method 120, the lens 10 is held by the workpiece holder 42 in the second orientation 86 different from the first orientation 80.

[0108] In the step 124 of the method 120, the lens 10 is processed by the processing tool for establishing or adapting the progressive surface 12 of the lens 10 while the lens 10 is held by the workpiece holder 42 in the second orientation 86.

[0109] The steps 122 and 124 are performed before the steps 102 and 104, in particular before the steps 102, 104, 108, 110 and 112.

[0110] The present disclosure further includes configurations according to the following clauses:Clause 1 : A method (100, 120) for polishing a progressive surface (12) of a lens(10), wherein the method (100, 120) comprises the following steps: holding (102), by a workpiece holder (42), the lens (10) in a first orientation (80); and polishing (104), by a polishing tool (52), the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70).Clause 2: The method according to clause 1 , wherein the method (100) further comprises the following step: processing (106), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80).Clause 3: The method according to clause 1 , wherein the method (120) further comprises the following steps: holding (122), by the workpiece holder (42), the lens (10) in a second orientation (86) different from the first orientation (80); and processing (124), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the second orientation (86).Clause 4: The method according to any one of clauses 1 to 3, wherein the workpiece holder (42) comprises a workpiece spindle (46) for rotating the lens (10) about a rotation axis, wherein the central symmetry axis (70) is the rotation axis of the workpiece spindle (46).Clause 5: The method according to any one of clauses 1 to 4, wherein the tilt axis (82) coincides with a horizontal lens axis (14) of the lens (10).Clause 6: The method according to clause 5, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the lens (10) comprises the horizontal lens axis (14), wherein the distance portion zone (22) is arranged above the horizontal lens axis (14), wherein the near portion zone (24) is arranged below the horizontal lens axis (14).Clause 7: The method according to any one of clauses 1 to 6, wherein the tilt angle (a) is 0.5° to 3.0°, preferable 1.0° to 2.5°, in particular 2.0°.Clause 8: The method according to any one of clauses 1 to 7, wherein the method (100, 120) further comprises the following step: calculating (108) the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10).Clause 9: The method according to any one of clauses 1 to 8, wherein the workpiece holder (42) comprises a workpiece chuck (44) for holding, in particular clamping or blocking, the lens (10), wherein the workpiece chuck (44) is configured to hold the lens (10) in the first orientation (80).Clause 10: The method according to any one of clauses 1 to 8, wherein the workpiece holder (42) comprises an adjusting device (50), wherein the adjusting device (50) adjusts an orientation of the lens (10) with respect to the central symmetry axis (70), in particular for arranging the lens (10) in the first orientation (80).Clause 11 : The method according to any one of clauses 1 to 8, wherein the method further comprises the following step: adjusting, in particular by an adjusting device (50) of the workpiece holder (42), an orientation of the lens (10) with respect to the central symmetry axis (70) for arranging the lens (10) in the first orientation (80).Clause 12: The method according to any one of clauses 1 to 8, wherein the method (100, 120) further comprises the following steps: aligning (110), in particular by an aligning device (62), the lens (10) with respect to a reference direction, in particular in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in the reference direction; and inserting (112), in particular by a handling device (66), the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).Clause 13: The method according to any one of clauses 1 to 12, wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70).Clause 14: The method according to clause 13, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24) adjacent to the edge of the lens (10).Clause 15: A system (40) for polishing a progressive surface (12) of a lens (10), wherein the system comprises: a workpiece holder (42) that is configured to hold the lens (10) in a first orientation (80); and a polishing tool (52) that is configured to polish the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70).Clause 16: The system according to clause 15, wherein the workpiece holder (42) comprises a workpiece chuck (44) for holding, in particular clamping or blocking, the lens (10), wherein the workpiece chuck (44) is configured to hold the lens (10) in the first orientation (10).Clause 17: The system according to clause 15, wherein the workpiece holder (42) comprises an adjusting device (50), wherein the adjusting device (50) is configured to adjust an orientation of the lens (10) with respect to the central symmetry axis (70), in particular for arranging the lens in the first orientation (80).Clause 18: The system according to clause 17, wherein the system (40) further comprises a control device (68) that is configured to: calculate the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10); andcontrol the adjusting device (50) to adjust an orientation of the lens (10) with respect to the central symmetry axis (70), in particular for arranging the lens (10) in the first orientation (80).Clause 19: The system according to clause 15, wherein the system (40) further comprises an aligning device (62) and a handling device (66), wherein the aligning device (66) is configured to align the lens (10) with respect to a reference direction, in particular in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in the reference direction, and, wherein the handling device (66) is configured to insert the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).Clause 20: The system according to clause 19, wherein the system (40) further comprises a control device (68) that is configured to: calculate the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10); and control the alignment device (62) to align the lens (10) with respect to a reference direction, in particular in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in the reference direction, and control the handling device (66) to insert the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).Clause 21: The system according to any one of clauses 15 to 20, wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26)are substantially at the same height in a direction parallel to the central symmetry axis (70).Clause 22: The system according to clause 21 , wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24) adjacent to the edge of the lens (10).

Claims

Claims1. A method (100, 120) for polishing a progressive surface (12) of a lens (10), wherein the method (100, 120) comprises the following steps: holding (102), by a workpiece holder (42), the lens (10) in a first orientation (80); and polishing (104), by a polishing tool (52), the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70), wherein the workpiece holder (42) comprises a workpiece spindle (46) for rotating the lens (10) about a rotation axis, wherein the central symmetry axis (70) is the rotation axis of the workpiece spindle (46), characterized in that the method further comprises the following step: adjusting, in particular by an adjusting device (50) of the workpiece holder (42), an orientation of the lens (10) with respect to the central symmetry axis (70) for arranging the lens (10) in the first orientation (80).

2. The method according to claim 1 , wherein the method (100) further comprises the following step: processing (106), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80).

3. The method according to claim 1 , wherein the method (120) further comprises the following steps: holding (122), by the workpiece holder (42), the lens (10) in a second orientation (86) different from the first orientation (80); and processing (124), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the second orientation (86).

4. The method according to any one of claims 1 to 3, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the lens (10) comprises a horizontal lens axis (14), wherein the distance portion zone (22) is arranged above the horizontal lens axis (14), wherein the near portion zone (24) is arranged below the horizontal lens axis (14), wherein the tilt axis (82) coincides with the horizontal lens axis (14) of the lens (10).

5. The method according to any one of claims 1 to 4, wherein the tilt angle (a) is 0.5° to 3.0°, preferable 1 .0° to 2.5°, in particular 2.0°.

6. The method according to any one of claims 1 to 5, wherein the method (100, 120) further comprises the following step: calculating (108) the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10).

7. The method according to any one of claims 1 to 6, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24)adjacent to the edge of the lens (10), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70).

8. A system (40) for polishing a progressive surface (12) of a lens (10), wherein the system comprises: a workpiece holder (42) that is configured to hold the lens (10) in a first orientation (80); and a polishing tool (52) that is configured to polish the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70), wherein the workpiece holder (42) comprises a workpiece spindle (46) for rotating the lens (10) about a rotation axis, wherein the central symmetry axis (70) is the rotation axis of the workpiece spindle (46), characterized in that the workpiece holder (42) comprises an adjusting device (50), wherein the adjusting device (50) is configured to adjust an orientation of the lens (10) with respect to the central symmetry axis (70) for arranging the lens (10) in the first orientation (80).

9. The system according to claim 8, wherein the system (40) further comprises a control device (68) that is configured to: calculate the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10); andcontrol the adjusting device (50) to adjust an orientation of the lens (10) with respect to the central symmetry axis (70) for arranging the lens (10) in the first orientation (80).

10. The system according to claim 8 or 9, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24) adjacent to the edge of the lens (10), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70).

11. A method (100, 120) for polishing a progressive surface (12) of a lens (10), wherein the method (100, 120) comprises the following steps: holding (102), by a workpiece holder (42), the lens (10) in a first orientation (80); and polishing (104), by a polishing tool (52), the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70), wherein the workpiece holder (42) comprises a workpiece spindle (46) for rotating the lens (10) about a rotation axis, wherein the central symmetry axis (70) is the rotation axis of the workpiece spindle (46), characterized in that the method (100, 120) further comprises the following steps:aligning (110), in particular by an aligning device (62), the lens (10) with respect to a reference direction; and inserting (112), in particular by a handling device (66), the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).

12. The method according to claim 11 , wherein the method (100) further comprises the following step: processing (106), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80).

13. The method according to claim 11 , wherein the method (120) further comprises the following steps: holding (122), by the workpiece holder (42), the lens (10) in a second orientation (86) different from the first orientation (80); and processing (124), by a processing tool (56), the lens (10) for establishing or adapting the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the second orientation (86).

14. The method according to any one of claims 11 to 13, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the lens (10) comprises a horizontal lens axis (14), wherein the distance portion zone (22) is arranged above the horizontal lens axis (14), wherein the near portion zone (24) is arranged below the horizontal lens axis (14), wherein the tilt axis (82) coincides with the horizontal lens axis (14) of the lens (10).

15. The method according to any one of claims 11 to 14, wherein the tilt angle (a) is 0.5° to 3.0°, preferable 1.0° to 2.5°, in particular 2.0°.

16. The method according to any one of claims 11 to 15, wherein the method (100, 120) further comprises the following step: calculating (108) the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10).

17. The method according to any one of claims 11 to 16, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24) adjacent to the edge of the lens (10), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70).

18. A system (40) for polishing a progressive surface (12) of a lens (10), wherein the system comprises: a workpiece holder (42) that is configured to hold the lens (10) in a first orientation (80); and a polishing tool (52) that is configured to polish the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (a), wherein the tilt axis (82) is perpendicular to a central symmetry axis(70), wherein the workpiece holder (42) comprises a workpiece spindle (46) for rotating the lens (10) about a rotation axis, wherein the central symmetry axis (70) is the rotation axis of the workpiece spindle (46), characterized in that the system (40) further comprises an aligning device (62) and a handling device (66), wherein the aligning device (66) is configured to align the lens (10) with respect to a reference direction, wherein the handling device (66) is configured to insert the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).

19. The system according to claim 18, wherein the system (40) further comprises a control device (68) that is configured to: calculate the first orientation (80) based on lens parameters of the progressive surface (12) of the lens (10); and control the alignment device (62) to align the lens (10) with respect to a reference direction, in particular in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in the reference direction, and control the handling device (66) to insert the aligned lens (10) into a workpiece chuck (44) of the workpiece holder (42) in the first orientation (80) based on a relationship between the reference direction and the central symmetry axis (70).

20. The system according to claim 18 or 19, wherein the progressive surface (12) comprises a distance portion zone (22) and a near portion zone (24), wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein the distance portion edge zone (26) is a portion of the distance portion zone (22) adjacent to the edge of the lens (10), wherein the near portion edge zone (28) is a portion of the near portion zone (24) adjacent to the edge of the lens (10), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edgezone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70).

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