JP2002172550A - Polishing device, polishing method and workpiece obtained with use of the device or method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation such as waviness of a workpiece surface when, for example, polishing such a workpiece with a complicated surface form as an aspheric lens. SOLUTION: A polishing tool 50 has, in the internal space of an elastic body 52, contact detectors 61 for detecting whether a workpiece surface is in contact with fine sectional portions of the surface of abrasive cloth 53, to which the detectors are fixed, or not, and actuators 63 capable of moving pistons 63a axially to bring the fine sectional portions in or out of contact with the workpiece surface. A contact area calculator calculates a contact area between the workpiece surface and the abrasive cloth 53 from information from the contact detectors 61. A controller moves the polishing tool 50 while the abrasive cloth 53 is in contact with the workpiece surface with substantially constant force, and at the same time, operates the actuators 63 to keep the contact area between the workpiece surface and the abrasive cloth 53 substantially equal to a preset reference area from information from the contact area calculator and the like.

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 for polishing a lens, particularly an aspherical lens.

[0002]

2. Description of the Related Art A polishing apparatus for polishing a lens or the like is a type of polishing apparatus.
Conventionally, a workpiece holding unit that holds a workpiece to be polished,
A polishing tool comprising an elastic body attached to the support member and a polishing cloth covered with the polishing cloth, wherein the surface of the workpiece and the polishing cloth are brought into contact with substantially constant force, and While relatively rotating the workpiece holder and the polishing tool, they are relatively moved along a predetermined path to uniformly mirror-finish the workpiece surface without destroying (damaging) the shape accuracy obtained by precision grinding ( It is adapted to polish).

[0003]

However, in such a polishing apparatus, the surface of the workpiece and the polishing cloth are brought into contact with a substantially constant force. As a result, the contact pressure changes, and the surface of the workpiece may lose its shape, such as undulation (ripple). And the problem of such shape collapse,
This is particularly remarkable when the path for relatively moving the workpiece holder and the polishing tool is complicated, such as when the workpiece to be polished is an aspherical lens.

The present invention has been made in view of such a problem, and when a workpiece having a complicated surface shape such as an aspherical lens is polished, the surface of the workpiece is not deformed due to undulation or the like. It is an object of the present invention to provide a polishing apparatus, a polishing method, and the like having a configuration capable of preventing the occurrence of such a problem, improving uniform polishing properties, and obtaining a workpiece in which precision grinding shape precision is maintained with high precision.

[0005]

In order to achieve the above object, a polishing apparatus according to a first aspect of the present invention comprises a workpiece holding unit (for example, a rotary table 40 in the embodiment) for holding a workpiece to be polished. ) And polishing cloth (for example, polishing cloth 5 in the embodiment) on the elastic body attached to the support member.
A polishing tool overlying 3), wherein the workpiece holding portion and the polishing tool are relatively moved while the surface of the workpiece and the polishing cloth are in contact with substantially constant force. in the polishing apparatus which performs polishing of the object surface, the contact area detecting means for detecting a contact area between the coated abrasive and the workpiece surface (e.g., the contact detector 61 in the embodiment, ... and the contact area calculator 62) , the contact area changing means for changing the contact area between the coated abrasive and the workpiece surface (e.g., an actuator 63 in the embodiment, ...) and, during polishing of a workpiece surface, the detection information from the contact area detector And control means (for example, the control device 70 in the embodiment) for controlling the operation of the contact area varying means so that the contact area between the workpiece surface and the polishing cloth is always substantially constant based on the above.

A polishing method according to a first aspect of the present invention is a polishing tool comprising a workpiece holding portion for holding a workpiece to be polished, and a polishing cloth covered by an elastic body attached to a support member. In the polishing method of polishing the surface of the workpiece by relatively moving the surface of the workpiece and the polishing cloth with a substantially constant force in contact with the surface of the workpiece, the contact area between the surface of the workpiece and the polishing cloth is reduced. The surface of the workpiece is polished while being controlled to be almost always constant.

[0007] In the polishing apparatus and the polishing method according to the first aspect of the present invention, when the surface of the workpiece is polished, the contact area between the workpiece surface and the polishing cloth is always substantially constant.
The contact area between the work surface and the abrasive cloth is controlled. For this reason, when polishing the surface of the workpiece, the contact pressure between the surface of the workpiece and the polishing cloth is almost always constant,
The occurrence of shape deformation such as undulation is prevented, and the uniform polishing accuracy of the workpiece is improved.

The polishing apparatus according to the second aspect of the present invention includes a workpiece holding portion (for example, the rotary table 40 in the embodiment) for holding a workpiece to be polished, and an elastic body attached to a support member. A polishing tool that covers a cloth (for example, the polishing cloth 53 in the embodiment); and a work holding unit in which the surface of the work is brought into contact with the polishing cloth with a substantially constant force. In a polishing apparatus for polishing a workpiece surface by relatively moving a polishing tool and a predetermined path,
Contact area detecting means for detecting the contact area between the workpiece surface and the polishing cloth (for example, the contact detector 61 in the embodiment,
61,... And a contact area calculator 62), and a contact area variable means (for example, actuators 63, 63, 63, in the embodiment) for changing the contact area between the workpiece surface and the polishing cloth.
...) And a contact area detecting means which is obtained when a scan is performed in which the workpiece holding portion and the polishing tool are relatively moved along the above-mentioned path in a state where the workpiece surface and the polishing cloth are brought into contact with substantially constant force. Contact area data storage means (for example, a contact area data storage device 180 in the embodiment) for storing data of a contact area between the workpiece surface corresponding to the path and the polishing cloth based on the detection information from during polishing of the object surface, based on stored the data by the contact area data storage means, the contact area between the coated abrasive and the workpiece surface a control for actuating the contact area varying means to be substantially constant at all times Control means (for example, the control device 170 in the embodiment).

A polishing method according to a second aspect of the present invention is a polishing tool comprising a workpiece holder for holding a workpiece to be polished, and a polishing cloth covered by an elastic body attached to a support member. in preparative polishing method of polishing the surface with the coated abrasive and a predetermined path by a relative movement is allowed by the workpiece surface in a state of substantially contacting with a constant force of the workpiece, the workpiece surface and the coated abrasive The workpiece holding unit and the polishing tool are scanned relative to each other in the above-described path in a state in which the workpiece is brought into contact with a substantially constant force, and data of the contact area between the workpiece surface and the polishing cloth paper corresponding to the above-described path is obtained. a first step of acquiring, based on the data acquired in the first step, the contact area between the coated abrasive and the workpiece surface to polish the workpiece surface while controlling so as to substantially always constant And a second step to be performed.

[0010] In the polishing apparatus and a polishing method according to these second invention, the work surface obtained when performing the scanning and coated abrasive and the workpiece surface substantially being in contact with a constant force Based on the data of the contact area with the abrasive paper,
When polishing the work surface, the contact area is controlled so that the contact area between the work surface and the polishing cloth is almost always constant. For this reason, as in the case of the first aspect of the present invention, when polishing the surface of the workpiece, the contact pressure between the surface of the workpiece and the polishing cloth is always substantially constant, and a shape collapse such as undulation may occur. This improves the uniform polishing accuracy of the workpiece. In the polishing apparatus and the polishing method according to the second aspect of the present invention, the workpieces having the same shape are successively polished in the polishing performed by relatively moving the workpiece holder and the polishing tool in a predetermined path. In such a case, it is particularly suitable.

Here, in the polishing apparatus according to the first and second aspects of the present invention, the contact area detecting means may be arranged such that each of the minute sections constituting the surface of the polishing cloth comes into contact with the surface of the workpiece. It is preferable to detect whether the surface of the workpiece is in contact with the abrasive cloth by detecting whether or not the contact is made. Further, when the workpiece is made of a transparent material, the contact area detecting means detects the contact area between the workpiece surface and the polishing cloth measured through the workpiece from the non-polished surface side of the workpiece. It is preferable that the area of the contact portion is determined based on the shape of the contact portion.

Further, in the polishing apparatus according to the first and second aspects of the present invention, the contact area variable means is provided in a polishing tool, and each of the minute sections constituting the surface of the polishing cloth is machined. it is contacted with the object surface, or it is preferably composed of a plurality of actuators that can be separated. Alternatively, the contact area changing means is, the polishing tool was close to the workpiece, or it is preferably composed of a movable actuator in a direction to separate.

Further, since the workpiece obtained by polishing the surface of the workpiece by the above-described polishing apparatus and method does not lose its shape such as undulation, the workpiece can be maintained with high precision grinding precision. . In particular, if the workpiece is an aspherical lens, it is possible to obtain an aspherical lens that can maintain the precision of the finely ground shape with high accuracy, overcoming the conventional difficulty of polishing without causing shape collapse.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a lens polishing apparatus to which an embodiment of the polishing apparatus according to the first invention is applied. This lens polishing device
A worktable (lens) 10 to be polished is fixedly held on its upper surface by a vacuum chuck or the like, and a turntable 40 is provided at an upper position facing the turntable 40, and a polishing cloth 53 is attached to the lower surface. The polishing tool 50 is provided. Here, the workpiece 10
Is described as a spherical lens whose surface is a spherical shape, but this is merely an example, and the workpiece 10 may have another surface shape (for example, an aspherical lens).

The supporting frame 20 for holding the polishing tool 50 and these rotating table 40 includes a horizontal base 21, a first stage movable on the base 21 in the Y direction (direction perpendicular to the sheet) 22 And a vertical frame 23 provided to extend vertically to the first stage 22, and movable on the vertical frame 23 (that is, movable in the Z direction).
A second stage 24, a horizontal frame 25 which is provided to extend horizontally in the second stage 24, and the horizontal frame 25 above (movable i.e. in the X-direction) movable third stage 26 It is configured.

The first stage 22 can move on the base 21 in the Y direction by the operation of an electric motor M1 built therein, and the second stage 24 can move vertically by the operation of an electric motor M2 built therein. It can move on the frame 23. Further, the third stage 26 can move on the horizontal frame 25 by the operation of the electric motor M3 built therein. For this reason the third stage 26,
The operation of these electric motors M1 to M3, it is possible to perform freely moving three-dimensional parallel.

The rotary table 40 is horizontally mounted on the upper end of a rotary shaft 28 provided to extend upward from a table support 27 provided on the base 21 of the support frame 20. by driving the rotary shaft 28 actuates the electric motor M4 that is built in,
The workpiece 10 can be horizontally rotated while being held.

As shown in FIGS. 1 and 2, the polishing tool 50 is provided with an air cylinder 30 and a thin disk-shaped spring at the lower end of a spindle 29 extending downward from the third stage 26 of the support frame 20. An electric motor M5 mounted via the third stage 26 and incorporated in the third stage 26
Is operated to drive the spindle 29, whereby the entire polishing tool 50 can be rotated about an axis substantially parallel to the rotation center axis of the turntable 40. Further, the spindle 29 electric motor M mounted in the third stage 26
6 enables a swing in a plane parallel to the plane of the paper, and also operates the electric motor M7, which is also built in the third stage 26 and has a rotating shaft orthogonal to the electric motor M6, to operate the motor perpendicular to the paper. Swing in the plane is possible.

As shown in FIG. 2, the polishing tool 50 has a substantially hemispherical shape on the lower surface of a disk-shaped support member 51 to which the rotational power of the spindle 29 is transmitted via an air cylinder 30 and a disk-shaped spring 31. An elastic body (for example, rubber) 52 is provided, and a polishing cloth 53 is covered on an outer surface of the elastic body 52. Since the polishing cloth 53 is attached to the support member 51 via the elastic body 52 in this manner, the polishing tool 50
When the elastic body 52 is pressed against the workpiece 10, the elastic body 52 is elastically deformed, whereby the polishing pad 53 has a certain contact area on the surface of the workpiece 10 (hereinafter referred to as the workpiece surface 11).
Contact with. The spindle 29 is an air cylinder 30
By supplying air from an air supply path (not shown) into the cylinder chamber 30a, the polishing tool 50 is pressed against the workpiece 10 with a substantially constant force while the polishing cloth 53 is in contact with the workpiece surface 11, Work surface 11 and polishing cloth 5
3 so that an appropriate contact pressure can be applied.

[0020] The inside of the elastic body 52 is formed space, Within this space, work surface 11 and the contact for detecting a contact area between the polishing pad 53 area detecting means serving multiple contact detector 61, (The contact area detecting means comprises these contact detectors 61, 61,... And a contact area calculator 62 described later), and changes the contact area between the workpiece surface 11 and the polishing pad 53. There are provided a large number of actuators 63, 63, ... as contact area varying means.

As shown in FIG. 3, each of the actuators 63 is configured to be able to slide the piston 63a in the axial direction by electromagnetic drive control (or air drive control) from the control device 70. 63a
The tip of each of a number of micro-partitions obtained assuming that the surface of the polishing pad 53 is divided into a number of micro-parts,
It is attached across the elastic body 52. Therefore, each actuator 63 can contact or separate each minute section of the surface of the polishing pad 53 to which the piston 63a is attached from the workpiece surface 11 by the axial movement of the piston 63a. It is.

Each contact detector 61 is a piezoelectric element.
The actuators 63, 63,... Are located at the respective distal end portions, that is, at the coupling portions with the elastic body 52. Each contact detector 61 detects whether or not the workpiece surface 11 has come into contact with a micro-partition on the surface of the polishing cloth 53 to which the contact detector 61 is attached via the elastic body 52, and the detection information is shown in FIG. Output to the contact area calculator 62 as described above. This contact area calculator 62 outputs from the contact detectors 61, 61,.
The contact area between the workpiece surface 11 and the polishing cloth 53 is calculated based on the information on whether or not each of the micro-compartments constituting the surface of the polishing cloth 53 is in contact with the workpiece surface 11. The data of the contact area thus obtained is output to the control device 70 as shown in FIG.

Here, as shown in FIG. 4A, the workpiece surface 11 is in contact with the polishing pad 53, and the contact portion is a region indicated by a region D in FIG. 4B. ,
.. (These contact detectors 61, 61,... Are indicated by “○” in FIG. 4B) from the contact detectors 61, 61,. 53 micro-sections (each of these micro-sections are shown in FIG.
(Indicated by “□” in (B)) is output to the effect that it is in contact with the workpiece surface 11, and the contact detectors 61, 61,. microcompartments portion of installed polishing cloth 53 work surface 11
Is output. For this reason, the contact area calculator 62 determines, based on these pieces of information, that the minute section of the polishing pad 53 attached to itself has the workpiece surface 11.
Contact detector 6 that outputs information that it is in contact with
By calculating the total sum of the areas of the minute sections for 1, 61,..., The area of the region D, that is, the contact area between the workpiece surface 11 and the polishing pad 53 can be obtained.

The contact area calculator 62 also contact detector 6
The detection information received from 1, 61,... Therefore, the control device 70, the contact detector 61, based on information from ..., the actuators 63, so that the micro-compartment of the polishing cloth 53 mounted on the actuator 63 is in contact with the work surface 11 Or the micro-compartment of the polishing pad 53 attached to the actuator 63 of the workpiece surface 11
It is possible to perform control to change the contact area between the workpiece surface 11 and the polishing pad 53 by operating so as not to contact the surface.

The control device 70 also includes, as shown in FIG.
Control of the rotation operation of the turntable 40, the three-dimensional parallel movement of the third stage 26, the swing operation and the rotation operation of the polishing tool 50 in an arbitrary direction (that is, the electric motors M1 to M
7). When a polishing start switch 71 provided on a control panel (not shown) adjacent to the control device 70 is operated, the control device 70 The electric motors M1 to M7 are operated according to a polishing stroke program preset according to the surface shape, and the rotary table 40 and the polishing table 53 of the polishing tool 50 are brought into contact with the workpiece surface 11 with a substantially constant force. While relatively rotating the polishing tool 50, the polishing tool 50 is moved on a predetermined path (path set by a polishing stroke program).

FIGS. 5 and 6 show an example of the path of such a polishing tool 50 when the workpiece 10 is viewed from above. The paths indicated by arrows in both figures are the polishing cloth 5
3 is a path at the center of the contact portion between the work surface 3 and the workpiece surface 11;
In the example of FIG. 5, by reciprocating in the X direction with respect to the rotating workpiece 10 and moving in the Y direction,
The entire surface of the workpiece surface 11 can be polished.
In the example of FIG. 6, by moving spirally toward the center from the outer edge side with respect to a rotating workpiece, so that can be polished the entire area of the workpiece surface 11. The polishing tool 50 is moved along such a path while the polishing tool 5 is moving.
Zero rotation center (that is, rotation center of spindle 29)
However, it is controlled to perform a swinging operation as shown in FIG. 7 so that it is always perpendicular to the workpiece surface 11. In actual polishing of the workpiece 10, FIG.
The movement of the polishing tool 50 along the path shown in FIG.

During the polishing of the workpiece 10, the surface 11 of the workpiece and the polishing pad 5 are removed in order to prevent heat generation on the polished surface and to wash away the polishing debris to improve the polishing precision and the working efficiency.
Abrasive is sprayed and supplied to a contact surface with the nozzle 3 from an abrasive spray nozzle (not shown).

In this manner, the entire surface of the workpiece surface 11 is polished by the polishing tool 50. At this time, the controller 70 controls the workpiece surface 11 and the polishing cloth output from the contact area calculator 62 during this polishing. Information on the contact area with the sensor 53 and contact detectors 61 and 6 given via the contact area calculator 62
1, ... information (which microcompartments portion from the workpiece surface 11
Contact, or based on by one of the information are) spaced from the,
The actuator 6 is set so that the contact area between the workpiece surface 11 and the polishing pad 53 substantially matches a predetermined reference area.
3, 63, performs control to operate the ....

More specifically, this control will be described. When the detected contact area between the workpiece surface 11 and the polishing pad 53 is smaller than a predetermined reference area, the surface of the polishing pad 53 separated from the workpiece surface 11 is determined. The actuators 63, 63,... Corresponding to the minute sections are extended, and the minute sections on the surface of the polishing pad 53 corresponding to the actuators 63, 63,. When the detected contact area between the workpiece surface 11 and the polishing cloth 53 is larger than the reference area, the actuators 63, 63,... , And the micro-partitions on the surface of the polishing pad 53 corresponding to the actuators 63 are separated from the workpiece surface 11 to reduce the contact area.

[0030] Here, the actuator 63 for performing such operations, the polishing and the workpiece surface 11 detected the cloth 53
If the contact area with the workpiece 63 is smaller than the reference area, the actuator 63 adjacent to the actuator 63 located at the outermost edge of the minute section on the surface of the polishing pad 53 in contact with the workpiece surface 11 is selected, and If the detected contact area between the work surface 11 and the polishing cloth 53 is larger than the reference area, the polishing cloth 53 in contact with the work surface 11 is detected.
The actuator 63 located at the outermost edge of the micro section on the surface is selected.

The reason why the contact area between the workpiece surface 11 and the polishing pad 53 is always substantially constant as described above is that the workpiece surface 11 is polished when the workpiece surface 11 is polished as described above. This is because the polishing cloth 53 of the polishing tool 50 is brought into contact with the surface 11 with a substantially constant force.
If the contact area between the polishing pad 1 and the polishing pad 53 changes (the contact area is not almost constant at all times), the contact pressure changes and the work surface 11 may be deformed, such as undulation.

As described above, in the polishing apparatus according to the first aspect of the present invention (and the polishing method performed by using the polishing apparatus), when the workpiece surface 11 is polished, The contact area is controlled so that the contact area is almost always constant. For this reason, when polishing the workpiece surface 11, the contact pressure between the workpiece surface 11 and the polishing cloth 53 is almost constant at all times, and the deformation of the workpiece 10, such as undulation, is prevented. Polishing accuracy is improved. Further, the workpiece (here, a lens) 10 obtained by polishing the workpiece surface 11 by such a polishing apparatus (and the polishing method) does not have shape deformation such as undulation, so that the precision grinding shape precision is improved. It is a workpiece that maintains accuracy.

Here, as shown in FIG. 8, when the workpiece 10 is an aspherical lens (this is referred to as a workpiece 10 '), the polishing tool 50 is mounted on the spindle 2 as shown in FIG.
The workpiece 10 'is polished while the workpiece 9 is oscillated. However, as compared with the case where the workpiece 10 is a spherical lens as described above, the lens surface (this is referred to as the workpiece surface 11') and the polishing pad 53 are polished.
The change in the contact area with the contact becomes large. For this reason, it has conventionally been difficult to polish an aspherical lens without deforming the shape. However, according to the present invention, this point can be overcome, and a non-aspherical lens with a high precision grinding shape precision maintained. A spherical lens can be obtained.

When the workpiece 10 to be polished is made of a transparent material such as a lens, the contact area detecting means for detecting the contact area between the workpiece surface 11 and the polishing pad 53 is as described above. Instead of using the contact detectors 61, 61,... Provided at the distal end portions of the actuators 63, 63,. upcoming lens based on the contact portion of the shape of the workpiece surface 11 and the polishing pad 53 that can be seen it through (shape projected on the upper surface of the rotary table 40) and may be a configuration for obtaining the area .

For example, as shown in FIG.
Assuming that the workpiece 10 ′ is polished by the above, the shape detector 64 provided on the upper surface of the turntable 40 irradiates light upward, that is, toward the workpiece, so that the workpiece surface 11 and the polishing cloth 53 Shape of contact part (workpiece surface 11 and polishing cloth 53
(A shape obtained by projecting the contact portion with the upper surface of the turntable 40). The shape of the contact portion, for example, the polishing tool 50 is shaped S ₁ becomes that shown by the solid line of FIG. 8 (B) when in the position indicated by the solid line in FIG. 8 (A), the polishing tool 50 is shown in FIG. 8 (A) when in the position indicated by a chain line has a shape S ₂ shown by the chain line in FIG. 8 (B). Then, the shape detector 64 outputs information of the detected shapes to the contact area calculator 65 as shown in FIG. 9, and the contact area calculator 65 outputs a lens based on the information from the shape detector 64. Characteristics (refractive index, etc.) and polishing tools 5
The contact area between the workpiece surface 11 and the polishing pad 53 is calculated in consideration of the position / posture of 0. Then, the information calculated by the contact area calculator 65 is output to the control device 70 as shown in FIG.

The contact area changing means for changing the contact area between the work surface 11 and the polishing cloth 53 is also similar to that using the actuators 63, 63,. Alternatively, using an actuator that can move in the direction of separating, that is, an actuator that can move the spindle 29 in the axial direction, the detected contact area between the workpiece surface 11 and the polishing pad 53 is larger than a predetermined reference area. When the polishing tool 50 is small, the spindle 2
9 is moved to increase the contact area, and when the detected contact area between the workpiece surface 11 and the polishing cloth 53 is larger than the reference area, the spindle 29 is moved to the side where the polishing tool 50 is separated from the workpiece surface 11. It may be configured to be moved to reduce the contact area.

In the above-described polishing apparatus (and polishing method), the polishing of the workpiece surface 11 is performed by moving the polishing tool 50 relative to the rotary table 40 along a predetermined path. However, in the first aspect of the present invention, the polishing tool 50 does not necessarily have to be moved along a predetermined path, and a polishing apparatus (and a polishing method) for manually operating and moving the polishing tool 50 is required. It is also possible to apply.

Next, a description will be given of a lens polishing apparatus to which one embodiment of the polishing apparatus according to the second invention is applied. The configuration of the lens polishing apparatus according to the second aspect of the present invention is as follows.
The configuration of the lens polishing apparatus according to the first aspect of the present invention is substantially the same as that of the first embodiment.
1, 61,...), The contact area between the workpiece surface 11 and the polishing pad 53 during the handling of the data of the contact area between the workpiece surface 11 and the polishing pad 53 and the polishing are always substantially constant. Only the control method for operating the contact area variable means (for example, the actuators 63, 63,...) Is different.

That is, in the lens polishing apparatus according to the second embodiment of the present invention, when the scanning start switch 172 provided on the control panel (not shown) is operated as shown in FIG. The electric motors M1 to M7 are operated according to a polishing stroke program preset according to the surface shape of the workpiece 10 to be polished, and the polishing cloth 53 of the polishing tool 50 is brought into contact with the workpiece surface 11 with a substantially constant force. While the rotary table 40 and the polishing tool 50 are relatively rotated in this state, the scanning is performed by moving the polishing tool 50 on a predetermined path (path set by the polishing stroke program).

In the lens polishing apparatus according to the second aspect of the present invention, as shown in FIG. 10, a contact area data storage device 180 connected to a control device 170 is provided. At the time of the scanning, data of a contact area between the workpiece surface 11 and the polishing pad 53 corresponding to the path is stored based on detection information from contact area detecting means (for example, contact detectors 61, 61,...). .
Then, after this scanning, when the polishing start switch 171 provided on the control panel is operated, the control device 170 operates the electric motors M1 to M7 in accordance with the polishing process program used at the time of scanning, and the polishing is performed on the workpiece surface 11. Tool 5
While the rotating table 40 and the polishing tool 50 are relatively rotated in a state in which the polishing cloth 53 of 0 is in contact with a substantially constant force,
The polishing is performed by moving the polishing tool 50 on a predetermined path (path set by a polishing stroke program).

As described above, the controller 170 controls the polishing tool 50 while rotating the rotary table 40 and the polishing tool 50 relative to each other with the polishing cloth 53 in contact with the workpiece surface 11 with a substantially constant force. The workpiece surface 11 is polished by moving along a predetermined path (for example, by moving the paths as shown in FIGS. 5 and 6 a plurality of times). Based on the above data, the contact area varying means (for example, the actuators 63, 63,...) Is operated so that the contact area between the workpiece surface 11 and the polishing pad 53 substantially coincides with a preset reference area. The specific operation of the contact area varying means is the same as in the case of the lens polishing apparatus according to the first aspect of the present invention.

As described above, in the polishing apparatus according to the second aspect of the present invention (and the polishing method performed by using the polishing apparatus), the workpiece surface 11 is brought into contact with the polishing cloth 53 with a substantially constant force. Based on the data on the contact area between the workpiece surface 11 and the polishing cloth 53 obtained when scanning is performed, the contact area between the workpiece surface 11 and the polishing cloth 53 when polishing the workpiece surface 11 The contact area is controlled so that is always substantially constant. For this reason, as in the case of the first aspect of the present invention, when polishing the workpiece surface 11, the contact pressure between the workpiece surface 11 and the polishing cloth 53 is almost constant at all times, and the shape collapse such as undulation is caused. uniform polishing accuracy that is prevented workpiece 10 resulting is improved. Furthermore, such a polishing apparatus (and a polishing method) workpieces obtained by polishing the workpiece surface 11 by (where lens)
10 is also an aspherical lens which maintains the precision ground shape precision with high precision without shape deformation such as undulation.

[0043] The polishing apparatus and polishing method according to the second invention, in the polishing for rotating table 40 and the polishing tool 50 in a predetermined path by relative movement, the polishing of the workpiece 10 of the same shape It is particularly suitable when performing one after another.

In the polishing apparatus (and polishing method) according to the second aspect of the present invention, the workpiece 10 to be polished is
Is made of a transparent material like a lens,
The contact area detecting means for detecting the contact area between the workpiece surface 11 and the polishing cloth 53 includes the actuator 63,
63, contact detectors 61, 61,
Instead, the contact between the work surface 11 and the polishing cloth 53 which can be seen through the lens serving as the work 10 from the non-polishing surface side of the work 10 (the upper surface of the turntable 40). The configuration may be such that the area is calculated based on the shape of the portion (the shape obtained by projecting the contact portion between the workpiece surface 11 and the polishing pad 53 onto the upper surface of the turntable 40).

Further, the contact area varying means for changing the contact area between the workpiece surface 11 and the polishing pad 53 is also provided with the actuators 63, 63,.
Instead of those using, polishing tool 50 was close to the workpiece 10, or the actuator movable in the direction away, i.e. using an actuator capable of moving the spindle 29 in the axial direction, the detected workpiece surface When the contact area between the polishing pad 11 and the polishing pad 53 is smaller than a predetermined reference area, the polishing tool 50
On the side closer to 1 by moving the spindle 29 to increase the contact area, when the contact area between the detected workpiece surface 11 and the polishing pad 53 is larger than the reference area, the polishing tool 50 from the workpiece surface 11 Spindle 29 on the side to be separated
May be moved to reduce the contact area.

[0046] While there have been described the preferred embodiments of the present invention, the scope of the present invention is not limited to the above. For example, abrasive paper may be used instead of the abrasive cloth 53 in the above embodiment.

In the above-described embodiment, the polishing is performed by moving the polishing tool 50 with respect to the rotary table 40, that is, the workpiece 10. However, the rotary table 40 and the polishing tool 50 are determined in advance. It is only necessary to be able to relatively move along the path, and the polishing tool 5
A configuration in which the turntable 40 is moved with respect to 0, or a configuration in which both are moved may be employed. Workpiece 1
The polishing of 0 may be performed while rotating the rotary table 40 and the polishing tool 50 relative to each other, and it is not necessary to rotate both as in the above-described embodiment, and one of them may not be rotated. .

Further, in the above-described embodiment, an example is shown in which the present invention is applied to a lens polishing apparatus for polishing a lens, but the polishing apparatus (and polishing method) according to the present invention
The object to be polished is not limited to a lens, but may be another workpiece (for example, a semiconductor wafer).

[0049] In the present invention, the workpiece holding portion for holding a polishing object serving workpiece and (rotary table 40 in the above embodiment), formed by Kutsugae設 the coated abrasive to the elastic member attached to the support member The present invention can be generally applied to a polishing apparatus having a configuration including a polishing tool, and the configuration of a frame (the support frame 20 in the above-described embodiment) that supports them is not limited to that described in the above-described embodiment.

[0050]

As described above, according to the present invention, in the polishing apparatus and a polishing method according to the first invention, during the polishing of the workpiece surface, approximately the area of contact with the coated abrasive and the workpiece surface is constant at all times The contact area between the surface of the workpiece and the abrasive cloth is controlled so that the contact pressure between the surface of the workpiece and the abrasive cloth is almost constant when polishing the surface of the workpiece. Thus, the occurrence of shape deformation such as undulation is prevented, and the uniform polishing accuracy of the workpiece is improved.

In the polishing apparatus and the polishing method according to the second aspect of the present invention, the workpiece surface obtained when scanning is performed in a state where the workpiece surface and the polishing cloth are in contact with substantially constant force. Based on the data of the contact area between
When the work surface is polished, the contact area is controlled so that the contact area between the work surface and the abrasive cloth is always substantially constant, so that it is the same as in the first embodiment of the present invention. When polishing the surface of the workpiece, the contact pressure between the workpiece surface and the polishing cloth is almost constant at all times, and the deformation of the workpiece such as undulation is prevented, and the uniform polishing accuracy of the workpiece is improved. . In the polishing apparatus and the polishing method according to the second aspect of the present invention, the workpieces having the same shape are successively polished in the polishing performed by relatively moving the workpiece holder and the polishing tool in a predetermined path. In such a case, it is particularly suitable.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a lens polishing apparatus to which an embodiment of a polishing apparatus according to a first invention is applied.

FIG. 2 is a sectional view showing a configuration of a polishing tool in the polishing apparatus.

FIG. 3 is a block diagram showing a signal transmission system in the polishing apparatus.

FIG. 4 is a view for explaining a process of obtaining an area of a portion where a workpiece surface and a polishing cloth are in contact with each other by a contact detector and a contact area calculator in the polishing apparatus; (B) shows a state where the surface and the polishing cloth are in contact with each other;
Indicates a contact detector located in the area of the contact portion and a minute section of the polishing pad to which the contact detector is attached.

FIG. 5 is a diagram illustrating an example of a path of a polishing tool when polishing a lens as viewed from above a lens.

6 is a diagram showing a look at an example of a path of the abrasive tool from above the lens during lens grinding.

7 is a view of the swinging operation of the polishing tool from the side of the lens during lens grinding.

FIG. 8A is a diagram showing the swinging operation of the polishing tool when the workpiece is an aspherical lens as viewed from the side of the lens, and FIG. 8B is a view showing the contact between the workpiece surface and the polishing cloth; It is a figure which shows the example of the shape obtained by projecting a part on a rotating table upper surface.

FIG. 9 is a block diagram showing a signal transmission system corresponding to a modification of the polishing apparatus.

FIG. 10 is a block diagram showing a signal transmission system in a lens polishing apparatus to which an embodiment of the polishing apparatus according to the second invention is applied.

DESCRIPTION OF SYMBOLS 10 Workpiece 20 Support frame 40 Rotary table (Workpiece holding part) 50 Polishing tool 51 Support member 52 Elastic body 53 Polishing cloth (polishing cloth paper) 61 Contact detector (Contact area detecting means) 62 Contact area Calculator (contact area detection means) 63 Actuator (contact area variable means) 70 Control device (control means)

Claims (10)

[Claims] 1. A workpiece holding portion for holding a workpiece to be polished, and a polishing tool comprising an elastic body attached to a support member and a polishing cloth covered with a polishing tool, wherein the surface of the workpiece is In a polishing apparatus for polishing the surface of the workpiece by relatively moving the workpiece holding unit and the polishing tool in a state where the polishing cloth is in contact with the polishing cloth at a substantially constant force, the workpiece surface and the polishing A contact area detecting means for detecting a contact area with the abrasive cloth; a contact area variable means for changing a contact area between the workpiece surface and the abrasive cloth; and the contact area when polishing the workpiece surface. Control means for controlling the operation of the contact area varying means so that the contact area between the workpiece surface and the polishing cloth is always substantially constant based on the detection information from the detection means. Characteristic polishing equipment. 2. A workpiece holding portion for holding a workpiece to be polished, and a polishing tool comprising an elastic body attached to a support member and a polishing cloth covered with a polishing tool, wherein the surface of the workpiece is In a polishing apparatus for polishing the surface of the workpiece by relatively moving the workpiece holding portion and the polishing tool in a predetermined path in a state where the polishing cloth and the polishing cloth are contacted with a substantially constant force, A contact area detecting means for detecting a contact area between a work surface and the polishing cloth; a contact area variable means for changing a contact area between the work surface and the polishing cloth; Based on detection information from the contact area detection means obtained when a scan is performed in which the workpiece holding unit and the polishing tool are relatively moved along the path while the cloth paper is being contacted with a substantially constant force. The workpiece corresponding to the path A contact area data storage means for storing data of a contact area between a surface and the polishing cloth; and, when polishing the workpiece surface, the workpiece based on the data stored by the contact area data storage means. polishing and wherein the contact area of the surface and the abrasive cloth paper and control means for controlling to operate said contact area varying means to be substantially constant at all times. 3. The workpiece surface and the polishing cloth by detecting whether or not each of the micro-partitions constituting the surface of the polishing cloth paper is in contact with the workpiece surface. 3. The polishing apparatus according to claim 1, wherein the polishing apparatus is configured to detect a contact area with paper. Wherein serves from the workpiece of transparent material, the contact area detecting means, the polishing and the workpiece surface from the non-polishing surface side of the workpiece is measured it through the workpiece claim, characterized in that it is configured to determine the area of the contact portion based on the shape of the contact portion between the fabric sheet 1
Or the polishing apparatus according to 2. 5. The contact area varying means is provided in the polishing tool, and is capable of bringing each of the micro-partitions constituting the surface of the polishing cloth into contact with or away from the workpiece surface. The polishing apparatus according to any one of claims 1 to 4, comprising a plurality of actuators. 6. The apparatus according to claim 1, wherein said contact area changing means comprises an actuator movable in a direction to move said polishing tool toward or away from said workpiece. A polishing apparatus according to claim 1. 7. A polishing apparatus comprising: a workpiece holder for holding a workpiece to be polished; and a polishing tool comprising an elastic body attached to a support member and a polishing cloth covered with the polishing tool. In a polishing method for polishing the surface of the workpiece by relatively moving the workpiece while contacting the cloth with a substantially constant force, a contact area between the workpiece surface and the polishing cloth is always substantially constant. Polishing the workpiece surface while controlling the polishing method. 8. A polishing apparatus comprising: a workpiece holder for holding a workpiece to be polished; and a polishing tool comprising an elastic body attached to a support member and a polishing cloth covered with the polishing tool. In a polishing method for polishing the surface of the workpiece by relatively moving the cloth in a predetermined path in a state of contacting the cloth with a substantially constant force, a substantially constant force is applied between the surface of the workpiece and the polishing cloth. the workpiece holding portion and the said polishing tool performs scanning for relatively moving in the path, to acquire data of the contact area between the workpiece surface and the abrasive cloth paper corresponding to the path in a state in which in contacted A first step, based on the data obtained in the first step, while controlling the contact area between the workpiece surface and the polishing cloth to be substantially constant at all times, And a second step of polishing. Polishing method according to claim. 9. A workpiece obtained by polishing the workpiece by the polishing apparatus according to any one of claims 1 to 6 or the polishing method according to claim 7 or 8. 10. The workpiece according to claim 9, wherein said workpiece is an aspheric lens.