EP3106262A1 - Polishing apparatus for polishing lenses surfaces on optical lenses and method for the operation thereof - Google Patents

Abstract

The invention relates to a polishing apparatus (1) for polishing curved lens surfaces (101) of optical lenses (100), the polishing apparatus (1) comprising a workpiece holder (10) for receiving an optical lens (100) and a polishing tool (20) the polishing tool (20) has a carrier element (21), an elastic substructure (22) and a curved polishing surface (23) on the elastic substructure (22), wherein the polishing tool (20) with the polishing surface (23) rotates about an axis of rotation ( R), the workpiece holder (10) being driven in rotation about a first axis (A1) to rotate the optical lens (100), a distance (z) between the workpiece holder (10) and the polishing tool (20). is adjustable along a second axis (A2), wherein an offset (x) between the workpiece holder (10) and the polishing tool (20) along a third axis (A3) which is aligned transversely to the first axis (A1) is adjustable, and where e in the angle of attack (W) between the rotation axis (R) and the first axis (A1) by tilting about a fourth axis (A4) is adjustable. Moreover, the invention relates to a method for their operation.

Description

The invention relates to a polishing apparatus for polishing curved lens surfaces of optical lenses according to the preamble of claim 1 and a method for their operation according to claim 8.

To obtain an optically effective lens surface, optical lenses are polished with polishing devices. Thus, polishing devices are known from the prior art, which have a workpiece holder, which receive an optical lens and rotate about an axis of rotation. On the free lens surface, which may be concave, convex, toric, spherical and freeform, a polishing tool with a polishing surface is placed.

For processing concave lens surfaces is off DE 10 2007 026 841 A1 known to use a polishing tool, which has a carrier plate on which a resilient Substructure is applied. On the elastic base the polishing surface is arranged. By rotating the carrier plate thus also rotates the polishing surface about a rotation axis perpendicular to the carrier plate. The axes of rotation of the optical lens and a drive shaft of the polishing tool are aligned parallel. The carrier plate in turn is connected via a gimbal compensating joint with the drive shaft.

1. a) die Geschwindigkeit um die Rotationsachse des Werkstückhalters,
2. b) eine Position entlang einer ersten Verschiebeachse für einen seitlichen Versatz zwischen den Rotationsachsen des Werkstückhalters und des Polierwerkzeugs,
3. c) sowie eine Position entlang einer zweiten Verschiebeachse zur Einstellung des Abstands zwischen dem Werkstückhalter und dem Polierwerkzeug.

The polishing machines used in the prior art have to adjust the removal profile during polishing so three interpolating driven axes, namely

1. a) the speed about the axis of rotation of the workpiece holder,
2. b) a position along a first displacement axis for a lateral offset between the axes of rotation of the workpiece holder and the polishing tool,
3. c) and a position along a second displacement axis for adjusting the distance between the workpiece holder and the polishing tool.

The gimbal compensating joint forms a degree of freedom, so that the polishing tool is statically indefinitely placed on the lens surface and always rests flat on the lens surface, for which it oscillates around the compensating joint. The surface curvature of the polishing surface usually corresponds essentially to the surface curvature of the concave lens surface.

A disadvantage of such a configuration is that the polishing tool can be moved only very limited over a peripheral edge of the lens surface. This has the consequence that the contact pressure in the direction of the lens center drops sharply even with a small projection. Moving the polishing surface to an even greater extent beyond the peripheral edge, the polishing tool tilts.

A further disadvantage of such polishing tools is that the contact pressure force over the polishing surface causes the polishing removal of the lens surface to tend in the direction of a sphere. As a result, already produced optical geometries are polished on the lens surface. In order to be able to polish ever narrower radii on the lens surface, large contact pressures are required in order to approach them by elastic deformation of the carrier plate and / or the elastic substructure. As a result, the polishing tendency toward a sphere in these lens regions is enhanced.

The object of the invention is therefore to develop a polishing apparatus and a polishing method, with which lens surfaces can be machined, the overlays of spherical, toric and progressive effects and thus form free-form surfaces, which are described by pure point clouds, without polished during polishing these effects become. The device and method are also intended to enable fast, efficient and cost-effective polishing of such lens surfaces.

Main features of the invention are specified in the characterizing part of claim 1 and in claim 8. Embodiments are the subject of claims 2 to 7 and 9 to 15.

The invention relates to a polishing apparatus for polishing curved lens surfaces of optical lenses, the polishing apparatus comprising a workpiece holder for receiving an optical lens and a polishing tool, the polishing tool having a support member, a resilient substructure and a curved polishing surface on the elastic substructure, wherein the polishing tool wherein the polishing surface is rotationally driven about a rotation axis, wherein either the curved lens surface is concave and the curved polishing surface is convex or the curved lens surface is convex and the curved polishing surface is concave, the workpiece holder being rotationally driven about a first axis to rotate the optical lens wherein a distance between the workpiece holder and the polishing tool is adjustable along a second axis, wherein an offset between the workpiece holder and the polishing tool along a third axis, the transversely to the first axis of is adjustable, and wherein an angle of attack between the rotation axis and the first axis by tilting about a fourth axis, in particular active, is adjustable.

The polishing device has the advantage that an up to ten times higher polishing performance is achieved than with a gimbal-mounted polishing plate. In addition, a constant removal profile in narrower and wider radii can be achieved by tilting. In addition, the adjacent to the peripheral edge area can be edited very well and precisely. As a result, geometries on the optical surface are not polished out. Namely, there is no phenomenon that the polishing tool tends to work the lens surface in the direction of a sphere. Rather, it is possible with the elastic base of the polishing tool and the angle of attack to compensate for deviations caused by a progressive portion of the lens surface of a spherical portion relative surface of the polishing surface to a purely spherical partial contact surface. In addition, cylinder effects of up to ten cylinders can be produced with such a polishing device. The whole succeeds in a first variant for the processing of concave lens surfaces with a convex polishing surface and in a second variant for the processing of convex lens surfaces with a concave polishing surface. By converting, in particular automated, it is also possible with the device to polish a concave front lens surface and the opposite convex back lens surface. In particular, it is possible to produce very complex spectacle lenses.

The curved lens surface is on the front of the lens or the back of the lens. A peripheral edge of the lens does not count toward the curved lens surface. Optionally, the curved lens surface may be a partial surface of the lens front side or the lens back side. Preferably, optical lenses having a circular peripheral edge are polished. The peripheral edge bounds the lens front side and the lens back each at its periphery.

In this case, the first axis should be aligned substantially perpendicularly through the center of the curved lens surface. Accordingly, the first axis will be substantially or exactly perpendicular to a receptacle of the workpiece holder in which an optical lens is received.

Furthermore, the invention achieves that the polishing surface rotates in a defined rotationally symmetrical surface about the axis of rotation. In cardan pendulum storage as in the prior art, this is not the case. The rotationally symmetrical surface may in particular be a sphere, at least outside a contact surface with the lens surface, where elastic deformation of the polishing surface occurs.

The polishing surface should rotate around your center. Although the polishing surface can stand up to its center. In many applications, however, also polishing tools are used, in which an annular or ring-segment-shaped polishing surface is arranged around the center.

A relatively simple interpolating motion kinematics of the first, second, third and fourth axes is achieved when the first axis is parallel to the second axis.

According to a further refinement of the polishing apparatus, when an optical lens is accommodated in the workpiece holder, the polishing tool can be placed obliquely on the curved lens surface according to the angle of attack and by deformation of the elastic base a strip-shaped contact surface between the polishing surface and the curved lens surface can be formed. The angle of attack between the axis of rotation and the first axis should be so great that the polishing surface is partially lifted from the curved lens surface, so to speak hovers over the latter. In this case, a part of the polishing surface then floats laterally spaced from the contact surface above the lens surface. The stronger the polishing tool is pressed against the lens surface, the greater the contact pressure and the wider the contact surface. Both correlate with the removal rate. By adjusting the angle of attack, it is in particular possible to control a constant removal profile over the length of the contact surface. In particular, an angle of attack is suitable in which the polishing tool has no contact with the lens surface in the region of the axis of rotation. This makes the velocity vector profile in the contact area more constant.

A special embodiment also contributes to this, according to which the strip-shaped contact surface extends at both ends to a peripheral edge of the curved lens surface. This ensures that the contact pressure over the length and up to the ends of the strip-shaped contact surface can be regulated to a homogeneous value. For this, either the surface curvature of the convex polishing surface should be smaller than the surface curvature of the concave lens surface or the surface curvature of the concave polishing surface should be greater than the surface curvature of the convex lens surface. In addition, the diameter of the polishing surface is to be selected larger than the diameter of the lens surface to be polished, preferably at least 20% larger.

Furthermore, it is provided in a further embodiment of the polishing apparatus that it has an electrical control device, by which during a polishing process, in particular exclusively, the speed of rotation of the workpiece holder about the first axis, the distance between the workpiece holder and the polishing tool along the second axis, the offset between the workpiece holder and the polishing tool along the third axis, and the angle of attack between the rotation axis and the first axis are interpolating driven by tilting about the fourth axis.

The interpolation makes it possible to regulate the contact pressure of the contact surface over its length to a constant value. In addition, the contact pressure can be controlled to a desired value, which is higher, for example, at the beginning of polishing than at the end of polishing. As a result, the polishing progress produces a finer polishing finish. As an electrical control device is a CNC control into consideration.

According to a special variant of the polishing apparatus, the rotating drive of the workpiece holder is effected about the first axis with a first drive, the adjustment of the distance between the workpiece holder and the polishing tool along the second axis with a second drive causes the adjustment of the offset between the workpiece holder and causes the polishing tool along the third axis with a third drive, and causes the adjustment of the angle of attack between the axis of rotation and the first axis with a fourth drive. As a result, the interpolating interaction can be performed largely free, because the drives are independently controlled.

In this context, it should be mentioned that it is advisable to effect the rotation of the polishing tool with the polishing surface about the axis of rotation by a spindle drive.

In such an embodiment, the polishing apparatus may comprise an electrical control device, are driven by interpolating during a polishing process, in particular exclusively, the rotational speed of the first drive, the position of the second drive, the position of the third drive, and the position of the fourth drive. Rotary motors are therefore suitable for the first drive, and servomotors in particular for the second, third and fourth drives.

In a particular configuration of the control device, the angle of attack with the control device is regulated to a value in which there is a maximum uniform pressing force over the length of a strip-shaped contact surface between the polishing surface and the curved lens surface.

According to a particular embodiment of the polishing apparatus, the second axis and the third axis are mechanically coupled to the workpiece holder. This means that the workpiece holder moves absolutely along the second axis and the third axis. Thus, the optical lens moves in two spatial directions and thereby rotates about the first axis.

In an optional embodiment of the polishing apparatus, the fourth axis is mechanically coupled to the polishing tool. Accordingly, the polishing tool is tilted about the fourth axis. At the same time it can rotate around the axis of rotation. A simple interpolating kinematics is achieved when the axis of rotation intersects the fourth axis, preferably Plumb. In addition, a design is preferably selected in which the polishing tool is rigidly coupled to a drive axle. Neither angle nor length changes should be possible, so that a CNC-controlled defined position without degrees of freedom can be approached with the polishing tool. In particular, the polishing tool should not have a cardan compensating joint or be mounted on such.

Preferably, the workpiece holder is arranged geodetically above the polishing tool. Overburden and excess polishing agent thus do not fall on the lens surface to be polished, but fall down.

Particularly suitable is the device for processing curved lens surfaces with a toric basic shape, on which also progressive action surfaces can be contained.

The invention also relates to the use of a polishing device described above for polishing a curved lens surface of an optical lens, in particular of concave or convex lens surfaces. Also in use, depending on the configuration of the polishing apparatus, the advantages described above are achieved.

1. a) Aufnehmen einer optischen Linse mit dem Werkstückhalter, insbesondere bevor die folgenden Schritte durchgeführt werden,
2. b) Aufsetzen des Polierwerkzeugs mit der Polierfläche auf die gekrümmte Linsenfläche,
3. c) Rotieren des Polierwerkzeugs um die Rotationsachse, und
4. d) Durchführen eines Poliervorgangs durch interpolierendes Antreiben bzw. interpolierendes Modulieren
   • der Geschwindigkeit der Rotation des Werkstückhalters um die erste Achse,
   • des Abstands zwischen dem Werkstückhalter und dem Polierwerkzeug entlang der zweiten Achse,
   • des Versatzes zwischen dem Werkstückhalter und dem Polierwerkzeug entlang der dritten Achse, und
   • des Anstellwinkels zwischen der Rotationsachse und der ersten Achse durch Kippen um die vierte Achse.

In addition, the invention relates to a method for operating a polishing apparatus described above, in which the following steps are carried out:

1. a) picking up an optical lens with the workpiece holder, in particular before the following steps are carried out,
2. b) placing the polishing tool with the polishing surface on the curved lens surface,
3. c) rotating the polishing tool about the axis of rotation, and
4. d) performing a polishing operation by interpolating driving or interpolating modulation
   • the speed of rotation of the workpiece holder about the first axis,
   • the distance between the workpiece holder and the polishing tool along the second axis,
   • the offset between the workpiece holder and the polishing tool along the third axis, and
   • the angle of attack between the axis of rotation and the first axis by tilting about the fourth axis.

An advantage of this is that an up to ten times higher polishing performance is achieved than with a gimbal-mounted polishing plate. In addition, a constant removal profile in narrower and wider radii can be achieved by the modulated tilting about the fourth axis. In this case, the region of the lens surface adjoining the peripheral edge can also be processed very well and precisely. As a result, geometries on the optical surface are not polished out. It can be procedurally produced cylinder effects of up to ten cylinders. It is sufficient that during the polishing process, four axes interpolate with each other, namely the first, second, third and fourth axes. To carry out the polishing process, a polishing agent should be provided, which may be contained in the polishing surface or in a supplied fluid.

With the method, it can be achieved, in particular, that an interpolating movement of the second, third and fourth axes is performed with each revolution of the lens blank around the first axis. To increase the quality of the cut, the rotational speed about the first axis is preferably also simultaneously modulated. A good grinding pattern is achieved, in particular, when the interpolating movement of the second, third and fourth axes is continuous.

In a special embodiment of the method, an angle of attack is taken into account in the interpolating driving as the first target function, in which a maximum uniform pressing force is present over the length of a strip-shaped contact surface between the polishing surface and the curved lens surface. As a result, a uniform removal profile over the length of the contact surface is achieved. For this purpose, the shape and position of the polishing tool, as well as the shape and position of the optical lens or of its lens surface should be known as input variables.

A further optional method embodiment provides that the interpolating driving as a second objective function takes into account a strip-shaped contact surface between the polishing surface and the curved lens surface, which extends at both ends to a peripheral edge of the curved lens surface. This ensures that a constant pressure force can be present within the lens surface up to the end region of the strip-shaped contact surface.

According to a further embodiment of the method, the interpolating driving takes into account as a third objective function a maximum uniform pressing force over one revolution of the optical lens. Thus, not only in a stand view, a uniform pressing force over the length of the contact surface is achieved, but also during a progressive movement of the contact surface on the lens surface. As a result, a constant removal profile is achieved over the entire lens surface.

Furthermore, a supplementary embodiment of the method provides that the interpolating driving as the fourth objective function takes into account a constant removal profile in the contact surface between the polishing surface and the curved lens surface. In this case, in addition to the contact pressures in the contact surface, the relative speeds between the polishing surface and the lens surface are also taken into account. This results in homogeneously distributed ablation rates over the contact surface.

A method variant also contributes to a desired polishing behavior, according to which the angle of attack between the axis of rotation and the first axis rotates twice per revolution of the lens blank about the first axis, in particular exactly twice, around the fourth axis and back and forth becomes. This in particular, when a lens surface is polished with toric basic shape. In this way, the angle of attack can be adapted to the basic toric shape and it is achieved in each rotation angle over the length of the contact surface uniform contact pressure.

This is also helped by a method configuration according to which, per revolution of the lens blank about the first axis, the offset between the workpiece holder and the polishing tool oscillates twice, in particular exactly twice, along the third axis, in particular oscillates back and forth about a zero position. This in turn, especially when a lens surface is polished with toric basic shape.

Further contributes to a harmonic microsection a variant in which the adjustment of the offset between the workpiece holder and the polishing tool along the third axis is superimposed with an oscillating movement along the third axis, wherein the oscillatory movement is smaller than the adjustment of the offset. As a result, larger circular grinding paths are superimposed around the center of the lens surface by smaller circular grinding paths. The result is a particularly fine microsection, in which the larger bevel paths are not recognizable by refraction but blurred.

According to a preferred method implementation, the rotating of the polishing tool about the axis of rotation takes place between a start and a deceleration at a constant speed. Thus, the speed does not interpolate with the first, second, third and fourth axis. In particular, polishing of the polishing tool about the axis of rotation between starting and braking at a speed between 600 and 1500 revolutions per minute is suitable for polishing. The method should be performed such that the rotational speed of the polishing tool rotating about the axis of rotation between the start and the deceleration is higher than the maximum rotational speed of the rotation of the workpiece holder about the first axis. It is advisable to modulate the speed of rotation of the workpiece holder about the first axis during the polishing process to values between 0 and 100 revolutions per minute. With the rapidly rotating polishing surface, a high removal rate is achieved, while the distribution of the removal rate over the lens surface is effected by the interpolation on the side of the less rapidly acting first, second, third and fourth axes. Accordingly fast and efficient, the polishing process per optical lens is feasible.

Fig. 1

einen Schnitt durch einen Ausschnitt einer Poliervorrichtung;

Fig. 2

eine perspektivische Ansicht einer Poliervorrichtung mit zwei Arbeitsebenen;

Fig. 3

eine schematische Skizze zur Veranschaulichung der Kontaktfläche eines mit Anstellwinkel auf die Linsenfläche aufgesetzten Polierwerkzeugs; und

Fig. 4

eine perspektivische Ansicht einer Poliervorrichtung gemäß Fig. 2 jedoch dargestellt mit Gestell, Gehäuse und Sekundäreinrichtungen zum automatisierten Betrieb.

Further features, details and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. Show it:

Fig. 1

a section through a section of a polishing apparatus;

Fig. 2

a perspective view of a polishing apparatus with two working levels;

Fig. 3

a schematic diagram illustrating the contact surface of a patch with an angle on the lens surface polishing tool; and

Fig. 4

a perspective view of a polishing apparatus according to Fig. 2 however, illustrated with rack, housing and secondary equipment for automated operation.

In Fig. 1 one sees in a section through a section of a polishing device 1 how the polishing of a concave lens surface 101 of an optical lens 100 with a polishing tool 20 takes place.

The polishing apparatus 1 is composed of two corresponding units. In this case, the first unit comprises the recording and motion kinematics of the optical lens 100 with a workpiece holder 10. The second unit relates to the polishing tool 20 and its movement kinematics.

The polishing tool 20 has a carrier element 21 and an elastic substructure 22 between a convex polishing surface 23 and the carrier element 21. In this case, the polishing tool 20 with the polishing surface 23 is driven to rotate about an axis of rotation R. In particular, the polishing tool 20 is rotatably mounted on a tool holder, here in particular a tool drum 50. Here also a spindle drive 35 is arranged, with the polishing tool 20 is driven about the rotation axis R.

The tool drum 50 in turn is rotatably driven about a fourth axis A4. This rotation is used to set and regulate by means of a fourth drive A4, on the one hand, an angle of incidence W of the polishing tool 20 relative to the optical lens 100, and on the other hand to use different polishing tools, which are arranged on the circumference of the tool drum 50.

In the present case, the rotation axis R and the fourth axis A4 intersect perpendicularly. This makes the movement kinematics particularly easy. However, this cutting is not essential. Alternatively, a non-perpendicular orientation and / or a spaced arrangement are also conceivable.

In summary, therefore, the polishing tool 20 rotates about the axis of rotation R and can be aligned and adjusted by adjusting the angle of attack W to the lens surface 101. These are the only adjustable axes and degrees of freedom of the polishing tool 20. Thus, no gimbal-mounted polishing plate is provided.

The workpiece holder 10 is rotationally driven about a first axis A1 to rotate the optical lens 100 about its center. For this purpose, the optical lens 100 can be connected, in particular with its rear side 102 of the lens, either with a so-called block piece, or else a vacuum holder is used which holds the optical lens 100 by negative pressure on the rear side of the lens 102.

With respect to the optical lens 100, the diameter D2 of the lens surface 101, the peripheral edge 103, and the surface curvature K2 of the lens surface 101 are also indicated.

Furthermore, the motion kinematics of the workpiece holder 10 is shown schematically. First, the workpiece holder 10 has a first drive 31 for effecting rotation around the first axis A1. By means of a second drive 32, the workpiece holder 10 can be moved back and forth along a second axis A2. The second axis A2 is present coaxial with the first axis A1. As a result, a simple motion kinematics is achieved. In addition, a third drive 33 is provided, with which the workpiece holder 10 is laterally movable back and forth; this particular transversely and in particular perpendicular to the second axis A2. These are the only three axes of movement of the workpiece holder 10. In addition, the first axis A1 is aligned perpendicularly through the center of the concave lens surface 101.

It is preferable that the fourth axis A4 intersect perpendicularly the plane defined by the second and third axes A2, A3. In addition, preferably also intersect the rotation axis R and the first axis A1.

In the present case, therefore, the first axis A1, the second axis A2 and the third axis A3 are mechanically coupled to the workpiece holder 10 or determine these three axes the degrees of freedom of the workpiece holder 10. The fourth axis A4 and the axis of rotation R are mechanically coupled to the polishing tool 20 or they determine the degrees of freedom of the polishing tool 20.

The first axis A1 and the axis of rotation R are to be arranged as described in order to effect the rotations of the lens 100 and the polishing tool 20. In contrast, it is basically possible in principle to mechanically couple the second axis A2 and the third axis A3 with the polishing tool 20 and / or mechanically couple the fourth axis A4 with the workpiece holder 10.

By means of this or said alternative arrangements and degrees of freedom of the workpiece holder 10 and of the polishing tool 10, it is now possible to adjust and regulate a distance z between the workpiece holder 10 and the polishing tool 20 along the second axis A2. At the same time, an offset x between the workpiece holder 10 and the polishing tool 20 along the third axis A3, which is aligned transversely to the first axis A1, adjustable and regulated. In addition, the angle of attack W between the axis of rotation R and the first axis A1 is actively adjusted and regulated by means of the fourth drive 34 by tilting about the fourth axis A4.

This makes it possible to place the polishing tool 10 obliquely on the concave lens surface 101 such that only part of the polishing surface 23 is in contact with the concave lens surface 101 occurs. This contact surface F is shown by an intersection between the polishing tool 10 and the optical lens 100. In reality, the elastic substructure 22 deforms. Another part of the polishing surface 23 is lifted off the lens surface 101. In a sense, it hovers above the lens surface 101. This also applies in particular to the center in the center M of the polishing surface 23 about the axis of rotation R.

By deformation of the elastic substructure 22, in particular, a strip-shaped contact surface F is formed between the polishing surface 23 and the concave lens surface 101, as will be explained in more detail below Fig. 3 is explained. The stronger the polishing tool 20 is pressed against the lens surface 101, the greater the contact pressure and the wider the contact surface F becomes. Both correlate with the removal rate. In addition, the removal rate is determined by the rotational speed of the polishing tool 20 about the axis of rotation R and the rotational speed of the optical lens 100 about the first axis A1.

• die Geschwindigkeit der Rotation des Werkstückhalters 10 um die erste Achse A1,
• der Abstand z zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der zweiten Achse A2,
• der Versatz x zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der dritten Achse A3, und
• der Anstellwinkel W zwischen der Rotationsachse R und der ersten Achse A1 durch Kippen um die vierte Achse A4

interpolierend angetrieben werden. Dies insbesondere indem

• der rotierende Antrieb des Werkstückhalters 10 um die erste Achse A1 mit dem ersten Antrieb 31 durch die Steuereinrichtung geregelt wird,
• die Verstellung des Abstands z zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der zweiten Achse A2 mit dem zweiten Antrieb 32 durch die Steuereinrichtung geregelt wird,
• die Verstellung des Versatzes x zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der dritten Achse A3 mit dem dritten Antrieb 33 durch die Steuereinrichtung geregelt wird, und
• die Verstellung des Anstellwinkels W zwischen der Rotationsachse R und der ersten Achse A1 mit dem vierten Antrieb 34 durch die Steuereinrichtung geregelt wird.

With the aid of an electrical control device can now during a polishing process, in particular exclusively,

• the speed of rotation of the workpiece holder 10 about the first axis A1,
• the distance z between the workpiece holder 10 and the polishing tool 20 along the second axis A2,
• the offset x between the workpiece holder 10 and the polishing tool 20 along the third axis A3, and
• the angle of attack W between the axis of rotation R and the first axis A1 by tilting about the fourth axis A4

be driven interpolating. This particular by

• the rotating drive of the workpiece holder 10 is controlled by the control device about the first axis A1 with the first drive 31,
• the adjustment of the distance z between the workpiece holder 10 and the polishing tool 20 along the second axis A2 with the second drive 32 is regulated by the control device,
• the adjustment of the offset x between the workpiece holder 10 and the polishing tool 20 along the third axis A3 with the third drive 33 is controlled by the control device, and
• the adjustment of the angle of attack W between the rotation axis R and the first axis A1 with the fourth drive 34 is regulated by the control device.

• die Rotationsgeschwindigkeit des ersten Antriebs 31,
• die Position des zweiten Antriebs 32,
• die Position des dritten Antriebs 33, und
• die Position des vierten Antriebs 34

interpolierend angetrieben. Es ist insbesondere eine Interpolation möglich, die über jeder Umdrehung des Linsenrohlings 100 um die erste Ache A1 eine interpolierende Bewegung der zweiten, dritten und vierten Achse A2, A3, A4 durchführt.By the electrical control device are during a polishing process, in particular exclusively,

• the rotational speed of the first drive 31,
• the position of the second drive 32,
• the position of the third drive 33, and
• the position of the fourth drive 34

driven interpolating. In particular, an interpolation is possible which performs an interpolating movement of the second, third and fourth axes A2, A3, A4 over each revolution of the lens blank 100 about the first axis A1.

In contrast, the rotational speed of the convex polishing surface 23 about the rotation axis R by the spindle drive 35 is preferably kept at a constant revolution number. This is preferably to be chosen so fast anyway that due to the rotational inertia a rapid modulation of the rotational speed is not possible. To prefer is a speed between 600 and 1500 revolutions per minute.

The rotational speed of the rotation of the polishing tool 20 about the rotational axis R between the start and the deceleration should also be higher than the maximum rotational speed of the rotation of the workpiece holder 10 about the first axis A1. Values between 0 and 100 revolutions per minute are particularly suitable as the maximum speed of rotation of the workpiece holder 10 about the first axis A1 during the polishing.

The angle of attack W is controlled as far as possible with the control device to a value in which over the length of the strip-shaped contact surface F between the polishing surface 23 and the concave lens surface 101, a maximum uniform pressing force is present. The larger the local surface curvature K2 of the lens surface K2, the larger the angle of attack W will be.

1. a) Aufnehmen einer optischen Linse 100 mit dem Werkstückhalter 10,
2. b) Aufsetzen des Polierwerkzeugs 20 mit der Polierfläche 23 auf die konkave Linsenfläche 101,
3. c) Rotieren des Polierwerkzeugs 20 um die Rotationsachse R,
4. d) Durchführen eines Poliervorgangs durch interpolierendes Antreiben
   • der Geschwindigkeit der Rotation des Werkstückhalters 10 um die erste Achse A1,
   • des Abstands z zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der zweiten Achse A2,
   • des Versatzes x zwischen dem Werkstückhalter 10 und dem Polierwerkzeug 20 entlang der dritten Achse A3, und
   • des Anstellwinkels W zwischen der Rotationsachse R und der ersten Achse A1 durch Kippen um die vierte Achse A4.

For operating a polishing apparatus 1, the following steps are carried out in particular:

1. a) picking up an optical lens 100 with the workpiece holder 10,
2. b) placing the polishing tool 20 with the polishing surface 23 on the concave lens surface 101,
3. c) rotating the polishing tool 20 about the rotation axis R,
4. d) performing a polishing operation by interpolating driving
   • the speed of rotation of the workpiece holder 10 about the first axis A1,
   • the distance z between the workpiece holder 10 and the polishing tool 20 along the second axis A2,
   • the offset x between the workpiece holder 10 and the polishing tool 20 along the third axis A3, and
   • the angle of attack W between the axis of rotation R and the first axis A1 by tilting about the fourth axis A4.

That is, exactly four axes interpolate with each other during polishing, namely, the first, second, third and fourth axes A1, A2, A3, A4. The rotation speed around the rotation axis R is taken into account (if at all) as a constant input quantity.

According to the method, it is possible for the interpolating drive to take into account as the first target function an angle of attack W in which there is a maximum uniform contact force over the length of a strip-shaped contact surface F between the polishing surface 23 and the concave lens surface 101. In addition, it can be regulated that the interpolating driving generates, as a third objective function, a maximum uniform pressing force over one revolution of the optical lens 100.

In addition, a strip-shaped contact surface F between the polishing surface 23 and the concave lens surface 101 can be traced by the interpolating driving as a second objective function, which extends at both ends E1, E2 to a peripheral edge 103 of the concave lens surface 101. Irrelevant is a lens edge that surrounds the concave lens surface 101 and does not need to be polished.

As described above, the removal rate also depends on the rotational speeds, in particular on the velocity vectors in the contact surface F. The velocity vectors can be determined in addition to the local pressing force solely on the basis of the positions of the workpiece holder 10, the polishing tool 20 and the surface shape of the lens surface 101. This makes it possible for the interpolating driving as the fourth target function to take into account a maximally constant removal profile in the contact surface F between the polishing surface 23 and the concave lens surface 101.

In Fig. 2 one sees a perspective view of a polishing device 1 with two working levels. In the working plane lying in front of the image, there is a workpiece holder 10 and a polishing tool 20 according to the section Fig. 1 , For clarity, only some of the technical features are provided with reference numerals.

In particular, it can be seen that the workpiece holder 10 holds an optical lens 100, which is processed by the polishing tool 20. The polishing tool 20 is composed of a carrier element 21, an elastic substructure 22 attached thereto and a polishing surface 23 on the elastic substructure 22.

As well as in Fig. 1 For example, the workpiece holder 10 can be displaced along the second axis A2 in order to be able to control a distance z between the workpiece holder 10 and the polishing tool 20. In addition, an offset x between the workpiece holder 10 and the polishing tool 20 can be controlled by displacing the workpiece holder 10 along a third axis A3. At the same time, the workpiece holder 10 including the optical lens 100 is rotated about a first axis A1.

On the other hand, the polishing tool 20 is driven to rotate about a rotation axis R. In addition, the tool drum 50, on which the polishing tool 20 is rotatably supported about the rotation axis R, can be rotated about a fourth axis A4 to control the angle of incidence W of the polishing tool 20 on the lens 100.

For further details on the workpiece holder 10 and the polishing tool 20, the description above Fig. 1 directed.

In Fig. 2 one recognizes further that an optional second working level is provided. This is functionally identical to the front working level. As a result, two lenses 100, 100a can be processed simultaneously and identically. In particular, the working planes are firmly connected with respect to the degrees of freedom of the workpiece holder 10, 10a and the polishing tool 20, 20a. The working planes also divide the drives so that the workpiece holders 10, 10a and the polishing tools 20, 20a move synchronously.

Another optional detail of the design Fig. 2 is that the tool drum 50 in each of the working levels over several, in particular four, in particular different polishing tools 20, 20a, 20b, 20c, 20d, 20e, 20f, 20g has. The third to eighth polishing tools 20b, 20c, 20d, 20e, 20f, 20g may also be polishing plates which have a gimbal compensating joint. These polishing plates then attach themselves to the lens surfaces of the lenses 100, 100a and oscillate around the gimbal compensating joint.

Fig. 3 1 shows a schematic sketch to illustrate the contact surface F of a polishing tool 20 which has an angle of incidence on a lens surface 101 of an optical lens 100.

The peripheral surface 103, the surface curvature K2 and the diameter D2 are also marked by the lens surface 101. By means of an optical transition line, it can be seen that the already pre-processed lens 100 has a toric lens surface 101. That is, the lens surface 101 to be polished is oval or elliptical. Two crescent-shaped edge areas do not need polishing.

Hatching is now particularly the contact surface F between the polishing surface 23 and the lens surface 101. This is strip-shaped and protrudes at both ends E1, E2 extends to a peripheral edge 103 of the concave lens surface 101. With other areas, the polishing surface 23 protrudes beyond the peripheral edge 103 at the ends E1, E2. Not recognizable are the parts of the polishing surface 23, as in Fig. 1 visibly float above the lens surface 101.

Also marked are the movements of the lens 100 about the first axis A1 and along the axis A3.

Fig. 4 shows a perspective view of a polishing apparatus 1 according to Fig. 2 however, shown with frame 41, housing 40 and secondary equipment for automated operation.

The frame 41 holds both the polishing tool 20 and the workpiece holder 10. The entire tool drum 50 together with the polishing tool 20 and the workpiece holder are arranged within the housing 40. On the front, the housing 40 has a viewing window and a flap or door. Good to see in the presentation of the Fig. 4 the drives 31, 32, 33, 34. The first drive 31 drives the workpiece holder 10 in rotation about the first axis A1.

The second and third drive 32, 33 are designed as cross slides, so that the displacements for controlling the offset x and the distance z are controllable.

Furthermore, one recognizes a transport rail 42, via which automatically preprocessed lenses 100a are provided and transported away again after processing.

With the aid of a loading device 43, the lenses 100, 100a are removed from the transport rail 42 before being polished and loaded into the workpiece holders 10. After polishing, they are removed again with the aid of the loading device 43 from the workpiece holder 10 and deposited for removal on the transport rail 42.

The invention is not limited to one of the above-described embodiments, but can be modified in many ways.

In particular, the above descriptions also apply to an optional modification in which the curved lens surface 101 is convex and the curved polishing surface 23 is concave. In particular, polishing tools 20b, 20c with a concave polishing surface 23 can be used in the tool drum 50 in addition to the polishing tools 20, 20a. Then, in the same polishing apparatus 1, concave and convex lens surfaces 101 are workable.

All of the claims, the description and the drawings resulting features and advantages, including design details, spatial arrangements and method steps may be essential to the invention both in itself and in various combinations.

LIST OF REFERENCE NUMBERS

1 polisher 50 tool drum 10 Workpiece holder 100 optical lens 10a second workpiece holder 100a second optical lens 20 polishing tool 101 lens surface 20a second polishing tool 102 Lens back 20b third polishing tool 103 circumferential edge 20c fourth polishing tool 20d fifth polishing tool A1 first axis (rotation) 20e sixth polishing tool A2 second axis (distance) 20f seventh polishing tool A3 third axis (offset) 20g eighth polishing tool A4 fourth axis (angle of attack) D1 Diameter (polishing surface) 21 support element D2 Diameter (lens area) 22 elastic substructure E1 first end (strip-shaped contact surface) 23 convex polishing surface E2 second end (strip-shaped contact surface) 31 first drive (first axis) 32 second drive (second axis) F strip-shaped contact surface 33 third drive (third axis) K1 Surface curvature (polishing surface) 34 fourth drive (fourth axis) K2 Surface curvature (lens surface) 35 spindle drive M Center (polishing surface) R axis of rotation 40 casing angle of attack 41 frame Z distance 42 transport rail x offset 43 loader

Claims (15)

Polishing device (1) for polishing curved lens surfaces (101) of optical lenses (100), - wherein the polishing device (1) has a workpiece holder (10) for receiving an optical lens (100) and a polishing tool (20), - wherein the polishing tool (20) has a support element (21), an elastic base (22) and a curved polishing surface (23) on the elastic base (22), wherein the polishing tool (20) with the polishing surface (23) rotating around a Rotation axis (R) is driven, wherein either the curved lens surface (101) is concave and the curved polishing surface (23) is convex or the curved lens surface (101) is convex and the curved polishing surface (23) is concave, wherein the workpiece holder (10) is driven in rotation about a first axis (A1) in order to rotate the optical lens (100), - wherein a distance (z) between the workpiece holder (10) and the polishing tool (20) along a second axis (A2) is adjustable, - wherein an offset (x) between the workpiece holder (10) and the polishing tool (20) along a third axis (A3), which is aligned transversely to the first axis (A1), is adjustable, characterized in that - An angle (W) between the rotation axis (R) and the first axis (A1) by tilting about a fourth axis (A4) is adjustable. Polishing device (1) according to claim 1, characterized in that when an optical lens (100) is received in the workpiece holder (20), the polishing tool (20) according to the angle of attack (W) obliquely on the curved lens surface (101) can be placed and by deformation of the elastic base (22) a strip-shaped contact surface (F) between the polishing surface (23) and the curved lens surface (101) can be formed. Polishing device (1) according to claim 2, characterized in that the strip-shaped contact surface (F) extends at both ends (E1, E2) to a peripheral edge (103) of the curved lens surface (101). Polishing device (1) according to one of the preceding claims, characterized in that it comprises an electrical control device, by means of which, during a polishing process, the speed of rotation of the workpiece holder (10) about the first axis (A1), the distance (z) between the workpiece holder (10) and the polishing tool (20) along the second axis (A2), the offset (x) between the workpiece holder (10) and the polishing tool (20) along the third axis (A3), and the angle of attack (W) between the axis of rotation (R) and the first axis (A1) by tilting about the fourth axis (A4) are driven interpolating. Polishing device (1) according to claim 4, characterized in that the setting angle (W) with the control device is regulated to a value in which over the length of a strip-shaped contact surface (F) between the polishing surface (23) and the curved lens surface (101) a maximum uniform pressing force is present. Polishing device (1) according to one of the preceding claims, characterized in that the second axis (A2) and the third axis (A3) are mechanically coupled to the workpiece holder (10). Polishing device (1) according to one of the preceding claims, characterized in that the fourth axis (A3) is mechanically coupled to the polishing tool (20). Method for operating a polishing apparatus (1) according to one of the preceding claims, characterized by the following steps: a) receiving an optical lens (100) with the workpiece holder (10), b) placing the polishing tool (20) with the polishing surface (23) on the curved lens surface (101), c) rotating the polishing tool (20) about the axis of rotation (R), d) performing a polishing operation by interpolating driving the speed of rotation of the workpiece holder (10) about the first axis (A1), the distance (z) between the workpiece holder (10) and the polishing tool (20) along the second axis (A2), - the offset (x) between the workpiece holder (10) and the polishing tool (20) along the third axis (A3), and - The angle of attack (W) between the axis of rotation (R) and the first axis (A1) by tilting about the fourth axis (A4). A method according to claim 8, characterized in that the interpolating driving as the first objective function takes into account an angle of attack (W) in which over the length of a strip-shaped contact surface (F) between the polishing surface (23) and the curved lens surface (101) a maximum uniform pressing force is present. A method according to claim 9, characterized in that the interpolating driving as a second objective function, a strip-shaped contact surface (F) between the polishing surface (23) and the curved lens surface (101) considered, located at both ends (E1, E2) to a peripheral edge (103) of the curved lens surface (101). Method according to one of claims 8 to 10, characterized in that the interpolating driving takes into account as a third objective function over a revolution of the optical lens (100) maximum uniform pressing force. Method according to one of claims 8 to 11, characterized in that the interpolating driving as the fourth objective function takes into account a constant removal profile in the contact surface (F) between the polishing surface (23) and the curved lens surface (101). Method according to one of claims 8 to 12, characterized in that per revolution of the lens blank (100) about the first axis (A1) of the angle of attack (W) between the rotation axis (R) and the first axis (A1) twice about the fourth axis (A4) is tilted back and forth. Method according to one of Claims 8 to 13, characterized in that the offset (x) between the workpiece holder (10) and the polishing tool (20) along the third axis (A3 ) commutes back and forth twice. Method according to one of claims 8 to 14, characterized in that the rotation of the polishing tool (20) about the rotational axis (R) between a start and a deceleration takes place at a constant speed.

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