JP2003039297A - Polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device capable of smoothing a surface to be polished provided with various kinds of curvatures such as an aspherical lens with a simple composition. SOLUTION: An abrasive part 2 can be deformed without changing the center position of the abrasive part 2, by supporting the approximate center section of the abrasive part 2 provided with an abrasive surface 2a with a pivot 7 and driving the both end sections in the Z axis direction with a driving means 9. A surface to be polished provided with various kinds of curvatures such as an aspherical lens can be smoothed by performing polishing with the abrasive surface 2a coinceding to the ideal profile and making close contact with the surface to be polished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and a polishing method used for polishing optical elements such as lenses and mirrors, dies, and the like, and more particularly to ultraprecision polishing of free-form surfaces such as aspherical surfaces. The present invention relates to a polishing apparatus and a polishing method with a variable shape used for the.

[0002]

2. Description of the Related Art Polishing tools using a polisher made of an elastic material have been generally used for finishing polishing optical elements such as lenses and mirrors, dies, etc., which require a high degree of shape accuracy. , The polishing surface of the polisher is pressed against the surface to be processed, and while the polishing liquid is supplied between the polishing surface and the surface to be processed, the polisher is rotated or rocked with respect to the surface to be processed. There is. At this time, if the surface to be processed is a spherical surface, it is usual to form the surface of the polisher with high accuracy so that the required radius of curvature of the spherical surface matches.

By the way, there are various shapes of workpieces,
For example, in the case where the radius of curvature changes like an aspherical surface, 1
If only one type of polishing tool is used for processing, the radius of curvature that changes on the surface to be processed (hereinafter also simply referred to as R) cannot be accommodated, and there is a difference in radius of curvature between the polishing surface of the polishing tool and the surface to be processed. In addition, a difference in pressure distribution occurs on the surface to be processed that the polishing tool contacts, and uniform polishing cannot be performed. In an extreme case, a gap may occur between the polishing surface and the surface to be processed, and only part of the polishing surface may act on the processing.

Further, as the polishing process progresses, the shape of the polishing surface of the polisher gradually deforms and deteriorates.
In order to maintain a constant radius of curvature, it is necessary to reshape the polishing surface by an operation such as sliding. The labor and time spent for this lapping work and interruption of the polishing process during that time lead to a decrease in manufacturing efficiency and an increase in manufacturing cost.

From the above, a polishing apparatus for machining which can arbitrarily form a polishing surface of a tool member so as to machine various curvature radii has been proposed, for example, Japanese Patent Publication No. 5-58664. The publication discloses a polishing apparatus in which the shape of the polishing surface, that is, the radius of curvature of the polishing surface is changed by using a plurality of driving means.

In this conventional polishing apparatus, as shown in FIG. 7, a plurality of displacement actuators 102, which can be individually operated by control means (not shown), are two-dimensionally arranged on a base 101, and the displacements of these displacement actuators 102 are arranged. By the operation of the actuator 102, a tool member 104 made of an elastic body that forms a tool surface having an arbitrary curved shape is attached to the member 103 on the output side which is displaced as a whole.

Further, Japanese Patent Laid-Open No. 2001-071245 also discloses a polishing apparatus in which the radius of curvature of the polishing surface is changed.

In this polishing apparatus, as shown in FIG. 8, the peripheral portion of the plate-shaped member 83 to which the polishing pad 82 is attached is fixed to the column member 84, and the plate-shaped member 83 is displaced in the pressing direction of the polishing surface. One actuator 85 for driving, a drive control means 87 for driving the actuator 85, and an arithmetic control means 88 for calculating a machining surface shape according to a machining position and deforming the polishing pad 82 via the drive control means 87 are provided. The actuator 85 is driven to deform the plate-shaped member 83 to which the polishing pad 82 is attached according to the designed ideal processed surface shape calculated at any processing position by the arithmetic control unit 88, and the polishing pad 82. The polishing surface 82a of No. 1 is forcibly matched with the ideal processing surface shape, the polishing surface 82a is brought into close contact with the surface to be processed without a gap, and the processing pressure is evenly applied to make It is obtained by allowing the smoothing of the surface to be processed, including waviness.

[0009]

However, the conventional polishing apparatus shown in FIG. 7 has the following problems.

Since a plurality of displacement actuators 102 are individually controlled to obtain a desired curved surface shape, the apparatus structure becomes complicated and expensive, and especially the radius of curvature changes continuously minutely. Such a gentle curved surface (for example, the amount of aspherical surface that is the deviation from the spherical surface is about 0.1 mm)
In such a case, it is not necessary to drastically change the radius of curvature of a part of the surface of the tool member 104, so that there is a problem in that the labor and cost are less effective.

For a surface to be machined with a large change in radius of curvature (for example, the maximum value of the amount of aspherical surface, which is the deviation from the spherical surface, is 0.5 mm or more), the yield stress of the member to be a polisher and the molding Since a polishing tool having a sufficiently small area (for example, φ20 mm) must be configured due to restrictions such as possible size, it is not possible to arrange a plurality of displacement actuators on the tool surface two-dimensionally. It is physically difficult with a size (even a small one, φ10 mm).

Further, in the conventional polishing apparatus shown in FIG. 8, the radius of curvature is changed in order to displace the plate-shaped member 3 at the center position in the pressing direction of the polishing surface, and at the same time the entire polishing apparatus is pressed in the pressing direction of the polishing surface. There is a problem in that the control becomes complicated because it has to be moved to.

Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art,
Provided are a polishing apparatus and a polishing method capable of handling a work surface having various radii of curvature such as an aspherical lens with a single tool and smoothly smoothing the work surface with a simple structure. The purpose is to do.

[0014]

In order to achieve the above object, a polishing apparatus of the present invention comprises a polishing member having a polishing surface,
The polishing member includes a supporting portion that supports a substantially central portion of the polishing member, a holding portion that holds both ends of the polishing member, and control means that acts on the holding portion, and the processing means processes the polishing member by the control means. It is characterized in that the shape of the contact surface with the surface is adjusted.

In the polishing apparatus of the present invention, it is preferable that the number of driving means is one.

In the polishing apparatus of the present invention, it is preferable that the polishing member is processed by adjusting its thickness.

In the polishing apparatus of the present invention, it is preferable that the polishing member is processed by adjusting its width.

The polishing method of the present invention comprises a polishing member having a polishing surface, and a supporting portion for supporting the substantially central portion of the polishing member.
And a holding unit that holds both ends of the polishing member, and causes the control unit to act on the holding unit, and controls the shape of the contact surface of the polishing member by the control unit based on the information of the surface to be processed of the workpiece. It is characterized by changing and polishing.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 (a) is a schematic configuration diagram of a first embodiment of a polishing apparatus of the present invention, FIG. 1 (b) is a bottom view of a polishing member, and FIG. 2 shows a polishing tool of the present invention. It is a schematic diagram which shows the aspect which processes an axisymmetric convex aspherical shape (optical lens) using 1st Embodiment.

In FIG. 1A, the polishing apparatus 1 includes a polishing member 2 (in this embodiment, a polishing pad (polisher) 3).
1 and a plate-shaped member 32 to which the polishing pad 31 is attached), a base member 4 serving as a position reference in the pressing direction (Z direction) of the polishing apparatus 1, and a plate-shaped member 32 with respect to the base member 4. A supporting portion (5 to 7) for positioning and supporting the central portion, and a holding portion for movably holding portions (for example, both end portions) facing each other in the longitudinal direction with the supporting portion of the plate-shaped member 32 as the center. (10 to 14) and one drive means 9 for displacing the holding part (10 to 14) in the pressing direction, and further, the amount of movement of the polishing apparatus 1 from the processed surface shape such as the radius of curvature and the drive means. The arithmetic control unit 16 that stores a machining program such as the drive amount of the drive unit 9 and the drive control unit that outputs the drive amount corresponding to the machining position from the arithmetic control unit 16 and outputs the drive current corresponding to the value to the drive unit 9. It is equipped with 15.

The polishing pad 31 is made of pitch, urethane foam or the like, and has a rectangular shape having a longitudinal direction and a lateral direction as shown in FIG. 1 (b). The polishing pad 31 is fixedly attached to the lower surface of a plate-shaped member 32 made of phosphor bronze, thin leaf spring steel, or the like by means such as adhesion, and the lower surface serves as the polishing surface 2a. Further, although the polishing pad 31 is shown as one piece which is wholly connected in FIGS. 1A and 1B, it can be formed by a plurality of pieces divided at several places. ,Also,
Instead of the divided pieces, grooves may be formed on the polishing surface 2a. Further, in this embodiment, the polishing member 2 is composed of the polishing pad 31 and the plate member 32.
You may use what the polishing pad and the plate-shaped member were integrated.

A support portion for positioning the central portion of the plate member 32 in the pressing direction (Z direction) is attached to the lower end of a column 5 extending downward from the base member 4 which serves as a position reference in the Z direction of the polishing apparatus 1. And a pivot 7 attached to the lower end of the V-shaped arm 6 and engaged with the central portion of the plate-shaped member 32. The central portion of the plate-shaped member 32 is moved in the Z direction. Base member 4 that serves as the position reference
To a predetermined position in the Z direction with respect to. The pivot 7 has a tip end portion formed into a curved surface shape such as a spherical surface, and is engaged and connected to the central portion of the plate-like member 32 through the tip end portion of this curved surface shape, and when the plate-like member 32 is laterally displaced or flexibly deformed. It is configured to eliminate the distortion of.

A holding portion for holding both ends of the plate member 32 so as to be movable is a guide base 10 extending in the X direction, having a central portion attached to a lower end portion of a driving means 9 fixed to the base member 4. , A guide bar 11 extending outward in the X direction from both side surfaces of the guide base 10 and having stoppers at the outer ends thereof, and both guide bars 11 slidable in the X direction along the guide bars 11. A pair of block bodies 12 mounted on the guide bar 10, and a (compression) coil spring 13 wound around the guide bar 11 between the guide base 10 and each block body 12 to apply a preload to each block body 12,
Both ends of the plate member 32 are attached to the lower part of each block body 12 by Y.
Bending pieces 3a each of which is composed of a rotating pin 14 for rotatably mounting around an axis and which is provided on both sides of both ends of the plate-like member 32 are positioned so as to sandwich the lower portion of the block body 12. By inserting the rotary pin 14 into the through hole provided in the plate member 32, the plate-shaped member 32 becomes rotatable about the Y axis with respect to the block body 12 via the rotary pin 14. A stopper is provided at the outer end of the rotating pin 14 to securely hold the plate member 32. It should be noted that the block body 12 has an X for inserting the guide bar 11.
Direction through-hole is provided, and X is centered on the guide bar 11.
Fitting is slidable in any direction. The guide base 10, the guide bar 11, the block body 12, and the coil spring 13 are combined to function as a guide in the horizontal (X direction) translation direction. In addition, the guide bar 11
Has described an example in which the guide bar 10 is fixed to the guide base 10 and slides in the through hole of the block body 12. However, conversely, the hole provided in the guide base 10 by fixing the guide bar 11 to the block body 12 side. It is also possible to insert it into a slide and slide it. The coil spring 13 is used for each block body 12.
The pre-load is applied to the plate base 32. However, its rigidity is sufficiently small so as not to hinder the flexural deformation of the plate-shaped member 32 when the guide base 10 is displaced in the pressing direction (Z direction). The natural length of the spring 13 is the plate-shaped member 3 whose both ends are attached to the block body 12, respectively.
2 is adjusted in advance so as to have an appropriate tension.

The driving means 9 has one end fixed to the base member 4 serving as a position reference in the pressing direction (Z direction), and the other end displaceable in the Z direction has the center of the guide base 10 constituting a holding portion. The parts are fixed, and the driving means 9 drives the holding parts such as the guide base 10 and the block body 12 to move in the Z direction. As the driving means 9, a voltage displacement conversion element such as a piezo element is used when a high speed response is required, and an air cylinder or an air cylinder is used when a large stroke is required although responsiveness is not required so much. Select a hydraulic cylinder to use. In addition, a mechanism that converts a direct drive pulse motor or a rotary type motor into a direct drive type (for example, a rack and pinion mechanism, a ball screw)
It is also possible to attach and use.

Further, the drive control means 15 is connected to the drive means 9 and is for controlling the drive of the drive means 9. The arithmetic control means 16 moves the polishing apparatus 1 from the machining surface shape such as the radius of curvature. A machining program such as the amount and the driving amount of the driving unit 9 is stored and connected to the driving control unit 15 so that the driving amount of the driving unit 9 according to the machining position is controlled by the driving control unit 15.
Output to.

Next, the polishing apparatus 1 is moved by the displacement of the driving means 9.
A mode for changing the shape of the polishing surface 2a will be described.

When the drive means 9 is displaced in the direction of arrow A with reference to the base member 4, the guide base 10 and both guide bars 11 attached to the drive means 9 in the central portion thereof.
Both of the block bodies 12 attached to the respective units move together in the direction of arrow A. At this time, the rotation pin 14 rotatably connected to the block body 12
Also moves in the Z direction, but since it has an X translational direction guide in which the rigidity and natural length of the coil spring 13 are adjusted appropriately,
The length of the plate member 32 does not change due to an unreasonable load, but the block body 12 slides and displaces in the X direction with respect to the guide base 10, and the distance from the guide base 10 is shortened. Furthermore, the plate-shaped member 3 is provided along the rotation pin 14.
Since both ends of 2 can rotate smoothly, the plate-shaped member 32
Is not overloaded. Further, since the central portion of the plate member 32 is positioned in the Z direction by the pivot 7, it does not move in the Z direction. Therefore, the plate-shaped member 3
Reference numeral 2 denotes a curved surface having a convex or concave radius of curvature, and the polishing surface 2a of the polishing pad 31 fixed to the plate-shaped member 32 also follows the radius-of-curvature surface of the plate-shaped member 32. The surface has a convex or concave radius of curvature. Further, since the displacement of the driving means 9 and the bending of the plate-shaped member 32 correspond to each other on a one-to-one basis, if the relationship between them is grasped in advance, the driving means 9 is displaced and the polishing surface 2a of the polishing pad 31 is moved. It is possible to form a surface having a desired radius of curvature. Needless to say, this surface includes an infinite radius of curvature, that is, a flat surface.

Next, a mode in which the workpiece L is polished by using the polishing apparatus 1 of the present embodiment configured as described above will be described with reference to FIG.

In FIG. 2, L is a workpiece such as an optical lens having a convex aspherical surface symmetric with respect to the central axis, and is attached by means such as vacuum suction or screwing or bonding through a jig (not shown). It is fixed to the holding body H, and a driving means (not shown) such as a motor that rotates at a constant speed around the central axis N is attached to the holding body H. The surface La to be processed of the workpiece L is pressed and brought into contact with the polishing surface 2a of the polishing pad 31 via an abrasive (not shown), and polishing is performed. Here, the polishing used for polishing the surface La to be processed. The pad 31 and the plate member 32 are set to have dimensions sufficiently smaller than the surface La to be processed. For example, a rectangular polishing pad 31 having a size of 20 mm × 6 mm is used for the surface La having a diameter of 200 mm.

The workpiece L is attached to the holder H and rotated by the drive means (not shown) in the clockwise direction about the central axis N at an arbitrary rotational speed Wr (for example, 10 rpm). From the position on the central axis N, which is the apex of the work surface La of the work piece L, in the radial direction outward (arrow C in the figure), the work surface La of the work piece L is driven by a driving unit (not shown). The upper part is moved at a constant speed v (for example, 5 mm / min). Therefore, apparently, the polishing apparatus 1 scans the workpiece L spirally from the center of the surface La to be processed toward the outer periphery.

Further, at this time, the polishing apparatus 1 uses the amplitude h and the frequency f (for example, the amplitude (h) is 2 mm and the frequency (f) is 5 Hz), that is, the average speed vr (vr, in order to increase the efficiency of the polishing process. > V, for example 20 mm / se
While swinging in the radial direction (arrow D in the figure) in c),
The surface La to be processed is processed. Further, in the polishing apparatus 1, it goes without saying that a load necessary for processing is applied from the polishing surface 2a of the polishing pad 31 to the surface La to be processed.

The processing position of the work piece L can be predicted in advance from the rotational speed Wr of the work piece L and the moving speed v of the polishing apparatus in the radial direction, and the arithmetic control means 16 is stored therein. From the machining program, the polishing apparatus 1 itself is moved onto the surface La to be machined of the workpiece L by a moving means (not shown), and the driving amount of the driving means 9 obtained from the design curvature radius R for the machining position is output. The drive means 9 of the polishing apparatus 1 can be driven via the drive control means 15 to match the shapes of the plate member 3 and the polishing pad 31 with a desired radius of curvature R. This means that even when the polishing apparatus 1 is near the center of the workpiece L (radius of curvature R ₁ , for example, R ₁ = about 300 mm), it is near the outer circumference (radius of curvature R ₂ (R ₂ <R ₁ <R ₁ ), For example R ₂ = 2
(About 00 mm) is completely the same.

As described above, the arithmetic control means 16 installed outside outputs the driving amount of the driving means 9 obtained from the ideal machining surface shape (for example, radius of curvature) at any machining position, and one end By driving the driving means 9 fixed to the base member 4 to move the guide base 10 in the Z direction, a plate-like plate having the band-shaped polishing pad 31 attached thereto so that the polishing pad 31 conforms to the processed surface shape. The member 32 can be flexibly deformed without causing local stress concentration or plastic deformation. As a result, the polishing surface 2a of the polishing pad 31 comes into close contact with the surface La to be processed without a gap, and the load applied to the polishing apparatus 1 is uniformly applied to the surface La to be processed as a processing pressure. Further, since the central portion of the plate member 32 is positioned by the pivot 7 so that the distance from the base member 4, which is the position reference of the polishing apparatus, is constant, the driving means 9 is driven to drive the plate member 32 and the polishing pad. Since the position of the central portion does not change even if the shape of 31 is changed, it is not necessary to move the entire polishing apparatus in the Z direction when the shapes of the plate member 32 and the polishing pad 31 are changed, the positioning accuracy is improved, and the control is simplified. Can be converted.

As a result, only by moving the polishing apparatus 1 along the work surface La of the work piece L, the work can be carried out smoothly and on the entire surface, and minute waviness which is a shape error component of a relatively short wavelength. The surface to be processed including (ripple) can be smoothed.

Further, since the shape of the work surface La is generally deviated from the designed ideal shape, it is formed in the polishing surface 2a by forcibly forming and processing the shape of the polishing pad 31. Surface to be processed L by utilizing the difference in pressure
It is also possible to correct the shape of a and bring it closer to the ideal shape.

As described above, by using the polishing apparatus of this embodiment, it is possible to perform polishing with a uniform pressure distribution even on a work surface having various radii of curvature such as an aspherical lens, Moreover, since a surface having various radii of curvature can be formed on a work surface having a wide variety of radii of curvature by a single driving means, a single tool can be used and the polishing apparatus can be controlled with a simple structure. Can be obtained. In the case of processing a concave aspherical surface, the curved surface formed by the plate-shaped member 32 of the polishing apparatus is made to have a convex shape corresponding to the concave shape of the workpiece, and the polishing is performed in the same manner as described above. However, detailed description thereof will be omitted.

Next, the mode of the second embodiment will be described with reference to FIG.

FIG. 3A is a side view showing details of the shape of the polishing member in the second embodiment, and FIG. 3B is a bottom view thereof.

As shown in FIG. 3 (b), the width b1 of the central portion (pressed by the pivot 7) of the polishing member 2 and the moving portions at both ends to be moved in the Z direction are the same (hereinafter referred to as the reference width b).
However, the polishing member 2 is processed so that the width b2 of the polishing member 2 (hereinafter, the intermediate width b2) in the intermediate portion between the two is the narrowest. (For example, b1 = 10 mm, b2 = 9.5 mm) Other members and configurations are the same as those in the first embodiment described above.

By forming the polishing member 2 into the above shape,
The portion having the narrowest width b2 has the lowest rigidity as compared with the reference width b1 and is easily deformed. Also in the polishing apparatus of this embodiment, the action of changing the curved surface shape of the polishing surface 2a of the polishing pad 31 by the displacement of the driving means 9 is the above-mentioned first.
The polishing apparatus is similar to that of the first embodiment, and the operation of the polishing apparatus when processing the workpiece is also the same. However, the polishing apparatus of the present embodiment has the following unique operation and effect.

If the width of the polishing member 2 is uniform at b1, the center portion and both end portions of the polishing member 2 are forcibly loaded, and a desired deformation is given, while the intermediate portion thereof is loaded with load. It has been confirmed by actual measurement that the amount of deformation is small (compared to the central portion and both end portions) because it is in a free state where it is not added. On the other hand, as described above, when the polishing member 2 of this embodiment in which the width of the middle portion is narrowed to b2 is used, the deformation amount becomes larger and the shape approaches a strict arc shape.

That is, if the width of the polishing member 2 is uniform at b1, there is a high possibility that the error with respect to the surface having the desired radius of curvature will be large, while the width at the intermediate portion is as narrow as b2 as described above. The smaller the error, the smaller the error.

Further, in the present embodiment, the polishing member used for polishing the convex aspherical surface-shaped workpiece is described. However, when polishing the concave aspherical surface-shaped workpiece, conversely, the intermediate portion is polished. The width may be widened in.

Next, a third embodiment of the polishing apparatus of the present invention will be described with reference to FIG. 4A is a side view showing details of the shape of the polishing member in the third embodiment of the polishing apparatus of the present invention, and FIG. 4B is a bottom view thereof.

This embodiment differs from the second embodiment described above in that the width of the polishing member 2 is not narrowed, but the width is uniform and the thickness t is partially thinned. is there. That is, as shown in FIG. 4A, the polishing member 2
The thickness t1 of the central portion and both end portions (hereinafter, reference thickness t1
The thickness of the intermediate portion is t2 (hereinafter, referred to as
The thickness is referred to as the intermediate thickness t2). (For example, for t1 = 0.3 mm, b2 = 0.29 mm)
Other members and configurations are the same as those in the first embodiment described above.

By forming the polishing member 2 into the above shape,
The portion having the intermediate thickness t2 has the lowest rigidity as compared with the reference thickness t1 and is easily deformed. In addition, according to the calculation formula of the section coefficient related to the rigidity of the polishing member, the rigidity is proportional to the width b while the rigidity is proportional to the cube of the thickness t, so that the effectiveness ratio of the thickness t is larger than that of the width b. Grows very large.

Also in the polishing apparatus of this embodiment, the action of changing the curved surface shape of the polishing surface 2a of the polishing pad 31 by the displacement of the driving means 9 is the same as that of the first embodiment described above, and further the workpiece is processed. Although the operation of the polishing apparatus when processing is the same, the polishing apparatus of the present embodiment has the following unique effect.

When the shape of the polishing member 2 is changed so that the polishing surface of the polishing apparatus has a desired radius of curvature, a change in the thickness t rather than the width b of the polishing member is more sensitively reflected in the rigidity value. Therefore, when the original shape has a large error compared with the desired radius of curvature, it has a great effect on matching the actual radius of curvature.

Further, in the present embodiment, the polishing member used for polishing the convex aspherical surface-shaped workpiece is described, but when polishing the concave aspherical surface-shaped workpiece, conversely, the intermediate portion is used. The thickness may be increased in.

Next, a method of processing the polishing member 2 described in the second and third embodiments will be described.

In the case of the second embodiment, the polishing member 2 is once manufactured with the width b in FIG. 3 being uniform, and is actually deformed to a desired radius of curvature to measure the shape error. Then, the width of the polishing member 2, more specifically, the width of the plate member 32 is additionally processed by punching or the like so as to reduce the error amount.

For example, when the difference between the actual shape of the polishing member 2 at the time of deformation and the desired radius of curvature is considered and the error amount is negative, the degree of deformation of the actual shape is insufficient. Therefore, in order to reduce the rigidity in the width direction, the width b2 is made narrower than the width b1. At this time, it is the most rational shape to make the portion narrowed from the width b1 to the width b2 into an arc shape in consideration of the ease of processing and the required accuracy.

The necessary accuracy is ensured by repeating the above-described work of measuring the deformed shape by trial and error.

Further, in the case of the third embodiment, also when adjusting the thickness t of the polishing member 2 in FIG. 4, it is the same as once measuring the shape and correcting it. At this time, the thickness t is originally thin, and the thickness t that is an adjustment portion by mechanical processing is
It is difficult to process 2 thinner, and it is necessary to remake the die for punching.

In the above processing method, it was confirmed that the size of the width b or the thickness t of the polishing member 2 was changed by actually making a shape, but the deformed shape was examined by simulation using a method such as the finite element method. However, the shape may be optimized so as to minimize the amount of error from the desired radius of curvature. By considering optimization of the shape by simulation, cost, time, resources, and labor can be saved dramatically.
Further, even when the shape is further changed from the examination result, the influence on the error value with the curved surface shape can be known, so that the shape can be changed more appropriately.

(Embodiment 1) FIG. 5 shows a simulation analysis of a polishing member having the shape (hereinafter, referred to as the original shape) of the polishing member 2 having a constant width b and thickness t and the polishing member having the shape shown in FIG. Then, it was compared with an ideal surface shape with a desired radius of curvature. The distance from the center line of the polishing member 2 is plotted on the horizontal axis, and the error amount from the ideal surface shape is plotted on the vertical axis.

In the figure, it was found that the error shape 61 of FIG. 3 was smaller than the error amount curve 60 of the original shape, and that the radius of curvature was closer to the ideal radius of curvature.

(Example 2) The rigidity of the coil spring 13 in the first embodiment is 0.1 kgf / mm and 0.05 kgf.
A simulation analysis of the deformed shape of the polishing member was performed at f / mm, and the results were compared.

When the rigidity of the coil spring 13 is changed, the error amount also changes, and in this embodiment, the error amount was smaller when the rigidity was reduced to 0.05 kgf / mm. By optimizing the rigidity of the coil spring in this way, it has become possible to more accurately approach the desired radius of curvature together with the optimization of the shape.

As described above, by examining the rigidity of the coil spring by simulation, the shape of the coil spring is not changed and
It has been found that the error amount can be finely adjusted even by a simple work of replacing the coil spring, which is advantageous in terms of cost and time.

[0062]

As described above, according to the present invention,
The control means drives the drive means based on the ideal machined surface shape (for example, radius of curvature) designed at an arbitrary machining position, moves the holding member in the direction perpendicular to the pressing surface, and moves the polishing member to its center. Since the portion can be deformed into an arbitrary curved surface without moving in the direction perpendicular to the pressing surface, the polishing apparatus can be configured easily and inexpensively.

In particular, when polishing an aspherical surface whose radius of curvature changes continuously, it is possible to create an arbitrary ideal machined surface shape with the minimum required labor and cost, and obtain the maximum effect. it can.

Further, for a surface to be processed having a large change in radius of curvature, a polishing apparatus having a sufficiently small area must be constructed due to constraints such as a yield stress of a member to be a polishing pad and a size which can be formed. Sometimes, but when it takes
Since the polishing apparatus of the present invention can be configured with a single driving means, it is suitable for configuring a tool having a small polishing surface size corresponding to a surface having a small radius of curvature.

Further, the polishing surface shape of the polishing apparatus can be forcibly matched with the ideal processing surface shape, the polishing surface of the polishing pad and the processing surface are in close contact with each other without a gap, and the load applied to the polishing apparatus is applied. Can be uniformly applied to the surface to be processed as a processing pressure, and the processing is performed smoothly and over the entire surface within the range of movement of the polishing equipment, resulting in minute waviness (ripple).
It becomes possible to smooth the surface to be processed, including.

As described above, a single tool can be used for a work surface having a wide variety of radii of curvature such as an aspherical lens, and a work surface having a wide variety of radii of curvature can be subjected to a uniform pressure distribution. Therefore, it is possible to provide a controllable polishing apparatus with a simple structure.

[Brief description of drawings]

1A is a schematic configuration diagram of a first embodiment of a polishing apparatus of the present invention, and FIG. 1B is a bottom view of a polishing member.

FIG. 2 is a diagram showing a polishing apparatus according to a first embodiment of the present invention,
It is a schematic diagram which shows the aspect which processes the axisymmetric convex aspherical shape.

FIG. 3A is a side view showing details of the shape of the polishing member in the second embodiment of the polishing apparatus of the present invention,
(B) is the bottom view.

FIG. 4A is a side view showing details of the shape of the polishing member in the third embodiment of the polishing apparatus of the present invention,
(B) is the bottom view.

FIG. 5 is a graph showing the deformed shape of the polishing member according to the second embodiment and the deformed shape of a plate-shaped member having a constant width b and thickness t in Example 1 of the polishing apparatus of the present invention, which are obtained from simulation analysis results. It is a comparison diagram of the error amount.

FIG. 6 is a comparison diagram of the amount of error obtained from the result of simulation analysis of the deformed shape of the polishing member by changing the rigidity of the coil spring in the second embodiment of the polishing apparatus of the present invention.

FIG. 7 is a perspective view showing an example of a conventional polishing apparatus.

FIG. 8 is a perspective view showing an example of a conventional polishing apparatus.

[Explanation of symbols]

1 Polishing device 2 Polishing member 2a Polished surface 31 polishing pad 32 plate-shaped member 4 Base member 5 props 6 V-shaped arm 7 pivot 9 Drive means 10 Guide base 11 Guide bar 11A, 11B guide bar 12 blocks 13 coil spring 14 rotating pins L Workpiece (optical lens) La Work surface

Claims (5)

[Claims] 1. A polishing member having a polishing surface, a support portion for supporting a substantially central portion of the polishing member, and a holding portion for holding portions facing each other in the longitudinal direction with the support portion of the polishing member as a center. A polishing apparatus comprising: a control unit that controls a driving unit that acts on the holding unit, and the control unit adjusts a shape of a contact surface of the polishing member with the surface to be processed. 2. The polishing apparatus according to claim 1, wherein the number of driving means is one. 3. The polishing apparatus according to claim 1, wherein the polishing member is processed by adjusting its width. 4. The polishing apparatus according to claim 1, wherein the polishing member is processed by adjusting its thickness. 5. A polishing member having a polishing surface, a support portion for supporting a substantially central portion of the polishing member, and holding portions for holding both ends of the polishing member, the control portion acting on the holding portion. Then, the polishing method is characterized in that the control means changes the shape of the contact surface of the polishing member based on the information of the surface to be processed of the object to be processed.