JP4127796B2 - Polishing tool for optical material, method for manufacturing the same, polishing apparatus and curvature correcting apparatus provided with the polishing tool. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing tool suitably used for polishing a high-precision spherical lens, optical flat plate (optical flat), or cylindrical lens (cylinder lens), a manufacturing method thereof, a polishing apparatus including the polishing tool, and a curvature thereof. It relates to a correction device.
[0002]
[Prior art]
Conventionally, the following polishing tools have been employed for various types of lens polishing.
[0003]
(1). Traditional pitch tool for polishing optical lenses
Traditional optical lens polishing pitch tools (commonly known as polishing dishes) are manufactured by the following method.
[0004]
First, a polishing dish substrate having a curvature obtained by adjusting the thickness of the pitch layer (T = about 3 to 6 mm) from the desired lens curvature radius (R) (in the case of a concave polishing dish: R + t, in the case of a convex polishing dish: R) -T), an excess pitch (optical polishing pitch separately heated and melted in a container) is dropped from an appropriate amount and stretched on the substrate.
[0005]
Next, a grip (grip) is attached to the back of the substrate, a pitch is applied on the burner, and reheating is performed. It is pressed against a mating plate having a desired lens curvature to shape the surface shape of the polishing tool, and the pitch layer is spread uniformly over the substrate.
[0006]
At this point, when turning the pitch, always turn your wrist, keep an appropriate distance on the burner and keep it evenly heated, and apply soapy water to the mating plate to make it easy to release. It is.
[0007]
If the pitch does not extend on the substrate at one time, the same operation is repeated.
[0008]
When the pitch expands and spreads on the substrate, the excess pitch protruding to the outer peripheral portion is cut off with a heated knife to shape the pitch layer.
[0009]
Next, a cotton net is laid on the mating plate, the pitch surface layer is wound by the same method as described above, pressed against the net, and the groove structure of the net is transferred and molded.
[0010]
When a polishing agent (slurry) is applied to the polishing tool manufactured by the above-described process and the lens is polished, a difference from the desired radius of curvature appears when the lens is examined with the Newton original apparatus. In order to meet the required specifications in optical design, it is necessary to reduce this difference. In general, a hand holding a replacement blade for a safety razor, the surface of the pitch layer of the polishing dish is removed by cutting, or the surface layer is dissolved and removed with an appropriate solvent. Alternatively, an extra groove is added to the surface of the polishing tool to promote activation of the flow of the pitch surface layer in that portion.
[0011]
That is, when it is desired to increase the curvature radius of the convex lens, the outer peripheral side of the polishing dish is removed. Conversely, when it is desired to reduce the curvature radius, the central part of the polishing dish is removed. On the other hand, in the case of a concave lens, when it is desired to increase the curvature radius, the central portion of the polishing dish is removed, and conversely, when the curvature radius is desired to be reduced, the outer peripheral side of the polishing dish is removed.
[0012]
The same applies when adding an extra groove.For example, if you want to increase the radius of curvature of the convex lens, add an extra groove on the outer periphery of the polishing plate, and conversely, if you want to reduce the radius of curvature, use the center of the polishing plate. Add extra grooves to the. There are various types of extra grooves such as a lattice type and a spiral type.
[0013]
In the traditional optical polishing production site, these operations are referred to as “changing the hit”. A state where the lens and the outer periphery of the polishing plate are in strong contact is called “strong”, and conversely, a state where the center is in strong contact is called “weak”. The optical polishing technician skillfully repeats the “changing the hit” operation to induce the radius of curvature to the design value on the optical drawing.
[0014]
An optical lens that is industrially used not only satisfies the surface processing error of sphericity and surface roughness, but the optical system is not established unless the radius of curvature is within an allowable error range.
[0015]
(2). G.Otte and AJLeistner polishing tools
Although limited to flat surfaces, G. Otte provides a 1 mm wide and 1 mm wide grid groove on the surface of the Pyrex (registered trademark) base material, and divides it into 3 mm square areas, and optically polishes the flatness. After the preparation, a pitch layer having a thickness of about 0.5 mm was formed and used as a polishing tool. It has been reported that the optical flatness with high flatness was obtained because the shape accuracy is not easily lost.
[0016]
It is a method focused on reducing the cause of the edge of the machined surface by analyzing it as fluid deformation due to frictional heat on the pitch surface layer.
[0017]
The above is described in the following documents.
[0018]
G.OTTE: An improved method for the production of optically flat surfaces, Journal of Scientific Instruments, vol.42 (1965)
Later, OTTE changed the above-mentioned polisher material from pitch to a Teflon (registered trademark) (FEP: Fluorinated ethylene propylene) material with better shape stability, thereby extending the life of the polisher. Although the opportunity to obtain a high-precision and high-quality surface has increased, there is a description that the pitch polisher is slightly smaller in scattered light from the polished surface.
[0019]
G.OTTE: the use of Teflon polishers for precision optical flats,
Journal of Scientific Instruments, vol.2 (1969) After G.OTTE, AJLeistner inherited and developed the above method.
[0020]
In addition to quartz glass, non-expandable ceramics such as Cer-Vit and ZERODURE (registered trademark) are recommended as tool base materials. Here, in addition to detailing a method of manufacturing a Teflon (registered trademark) polisher, a polishing method for obtaining a high-precision and high-quality surface by a polishing apparatus having a double eccentric mechanism is introduced.
[0021]
It also suggests that the Teflon (registered trademark) polisher may be suitable for polishing a spherical surface.
[0022]
A polishing member and a polishing apparatus made of a polymer resin are known (see Patent Document 1).
[0023]
[Patent Document 1]
JP-A-11-77517
[0024]
[Problems to be solved by the invention]
The conventional polishing tool described in the above (1) has a pitch layer with a thickness of about 3 to 6 mm, and the finished state of the workpiece is influenced by the viscoelasticity. In other words, in the case of a sample that has been optically polished with a polishing tool made of a pitch material that is relatively soft and exhibits delayed elasticity, the surface roughness is small and a smooth surface is obtained, and scratches are not easily formed, but the shape is easy to cause fraying. Accuracy deteriorates. On the other hand, in the case of a sample subjected to optical polishing with a polishing tool made of a pitch material that is relatively hard and does not exhibit delayed elasticity, the shape accuracy is good, but the surface roughness is large and scratches are likely to occur.
[0025]
With polishing tools used in traditional optical polishing methods, it is difficult to obtain a high-precision and high-quality surface.
[0026]
The special polishing tool described in the above (2) is intended to minimize surface defects and surface defects by forming a polisher material having inherently retarded elasticity only on the surface of the polishing tool and improving shape stability. At the same time, there is an aim to improve the shape accuracy. The polisher material for the tool surface layer is pitch and Teflon (registered trademark). The former is slightly superior in surface smoothness, and the latter is excellent in shape stability and tool life.
[0027]
However, a polishing tool with a thin pitch layer easily forms a polisher on the surface of the polished glass base material, and the peeled piece is caught on the work surface and causes troubles such as scratches and is difficult to handle. It was. The Teflon (registered trademark) layer solves this problem, but there is no embedding action of the fine particles, and therefore the surface roughness tends to be slightly inferior.
[0028]
In addition, there are inconveniences such as requiring a dedicated machine tool to perform lattice groove processing, spherical surface with curvature, cylindrical surface processing, etc. on the glass base material, suggesting the applicability of various curved surfaces, but practical Coverage remained largely confined to the plane.
[0029]
The essential reason why it is difficult to conform to the spherical surface is that a thin polisher layer has not been fully studied and developed because the radius of curvature correction method has been completed by the traditional optical polishing method. In optical manufacturers, the lens curvature radius used for optical design is equivalent to the original curvature of the company, and the curvature radius tolerance becomes stricter as the lens requires severe surface processing errors such as sphericity and surface roughness. In many cases, it is specified in the order of μm, and unless this problem is solved, practical use in spherical lens polishing is practically limited.
[0030]
A main object of the present invention is to provide a polishing tool that can be polished with high accuracy and a long life, a manufacturing method thereof, and a polishing apparatus and a curvature correcting apparatus including the polishing tool.
[0031]
[Means for Solving the Problems]
Examples of the solving means of the present invention are as follows.
[0032]
According to claim 1 of the present application, a polishing tool for polishing an optical material, wherein the base material is made of a carbon resin material, and a pitch layer is formed on the surface of the carbon resin material. It is.
[0033]
According to claim 2, the pitch layer has a thickness of 0.3 mm or less.
[0034]
According to claim 3, the surface of the carbon resin material is processed into any one of a spherical surface, a flat surface, and a cylindrical surface, and the surface of the carbon resin material has a lattice shape, a concentric circle shape, a radial shape, and a spiral shape. Any one of the grooves is formed in a predetermined pattern.
[0035]
According to a fourth aspect of the present invention, in the above polishing tool, the carbon resin material is modified or reinforced by the addition of fine particles or fibers having glass or metal.
[0036]
According to a fifth aspect of the present invention, there is provided the above polishing tool, wherein a plurality of segmented carbon resin materials are bonded onto a metal or ceramic rigid substrate.
[0037]
According to a sixth aspect of the present invention, in the above-mentioned polishing tool, the pitch layer is formed by drying a liquefied pitch after application.
[0038]
According to claim 7, the above-mentioned polishing tool is characterized in that the pitch is liquefied with a solvent and then the pitch is re-cured.
[0039]
According to the eighth aspect of the present invention, there is provided a polishing tool manufacturing method in which a base material made of a carbon resin material is formed into a predetermined shape, and then a liquefied pitch is applied to the surface of the carbon resin material.
[0040]
According to claim 9, the pitch is liquefied with a solvent, the liquefied pitch is applied to the surface of the carbon resin material, and the pitch is dried and re-cured to form a pitch layer. It is a manufacturing method of an abrasive tool.
[0041]
According to the tenth aspect of the present invention, there is provided a polishing apparatus for an optical material in which an upper shaft and a lower shaft are arranged to face each other, the above-described polishing tool is mounted on one of them, and the optical material is mounted on the other.
[0042]
According to the eleventh aspect, the polishing apparatus is configured such that the upper shaft and the lower shaft are arranged to face each other, and the above-described polishing tool can be mounted on both of them.
[0043]
According to a twelfth aspect of the present invention, there is provided a curvature correcting device in which an upper shaft and a lower shaft are arranged to face each other, the above-described polishing tool is mounted on one of them, and an electrodeposited diamond wheel is mounted on the other. is there.
[0044]
According to the thirteenth aspect of the present invention, the distance between the upper shaft and the lower shaft is configured to be relatively variable depending on the shapes of the polishing tool and the electrodeposited diamond wheel. .
[0045]
According to a fourteenth aspect of the present invention, there is provided the above-described curvature correcting device having an auxiliary device provided with two or more guide rollers in contact with the side surface of the electrodeposited diamond wheel.
[0046]
According to a fifteenth aspect of the present invention, there is provided the above-described curvature correcting device having an auxiliary device including a guide roller that comes into contact with the upper surface of the electrodeposited diamond wheel.
[0047]
According to a sixteenth aspect of the present invention, there is provided a polishing apparatus provided with the aforementioned curvature correcting device.
[0048]
As described above, the tool life is extended while maintaining the shape stability of the polishing tool, the “wetting” between the pitch layer formed on the surface layer and the tool surface is improved, and peeling is unlikely to occur. Further, it is possible to polish a high-precision spherical lens having a radius of curvature tolerance on the order of μm for a thin pitch polisher layer.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the base material of the polishing tool is made of a carbon resin material. As a result, the tool life can be extended while maintaining the shape stability, the shape accuracy can be improved, and sufficient time to reduce the surface roughness can be secured, and the wound of the polishing strip can be prevented. Since the carbon resin is essentially soft and has a tendency to easily adsorb abrasive grains, for example, even when the pitch layer is worn and exposed to the surface, damage to the surface of the counterpart component is extremely small.
[0050]
In addition, by using a carbon resin material as a base material, it is possible to easily perform curved shape processing and free grooving using general-purpose NC lathes and machine tools, and have a wide variety of shapes and groove structures. A polishing tool can be realized.
[0051]
Carbon resins are also advantageous in that they are less likely to corrode in various types of polishing liquids that exhibit acidity and alkalinity, and are difficult to crack in handling and work.
[0052]
The thickness of the pitch layer is preferably 0.3 mm or less. This is because when the thickness of the pitch layer exceeds 0.3 mm, the edge is likely to occur. More specifically, when the pitch layer is thicker than 0.3 mm, it becomes close to the properties of a conventional polishing tool, and the original hardness is generally lost with a solvent (that is, the molecular chain of the chain polymer hydrocarbon is removed). Although a divided pitch is used, plastic deformation easily occurs due to friction with the lens, and a sag occurs on the outer periphery of the lens surface, making it impossible to secure sphericity. The lower limit of the pitch layer is preferably 0.05 mm. This is because the possibility that the base material is locally exposed to the surface increases. If scratches due to contact with the exposed base material appear, it is the limit in use, and the operator grasps the life based on experience, and usually replaces the pitch before that.
[0053]
The measurement method of the thickness of the pitch layer is based on microscopic measurement with a deep focal depth, but relative comparative observation with a 0.3 mm mechanical pencil core is sufficient with a large loupe. When the pitch thickness is about the core of a 0.5 mm mechanical pen, a border appears. In the thickness measurement, 0.3 to 0.5 mm is the boundary region, but depending on the lens, it may be ground and removed by centering after polishing or may be outside the effective diameter.
[0054]
When forming the polisher layer, the pitch material is liquefied with a solvent, and the original hardness of the pitch (that is, the polymer chain-like semi-solid hydrocarbons are cut off with the solvent to form low-molecular semi-solid hydrocarbon particles. Is the turbidity ratio, the hardness when the viscometer needle (2 mmφ) sinks by 0.1 mm in a certain time (1 minute) when the temperature is constant (20 ° C.), or the fluidity Viscoelasticity due to instantaneous elasticity, delayed elasticity, etc. (see “Optical Industry Technology Research Association“ Lens / Prism Processing Technology '76 ”(issued on October 20, 1976))) should be lost. Thereby, the effect of burying the abrasive grains is increased, and an ultra-smooth optical surface can be obtained.
[0055]
The polishing tool of the present invention can adapt to various types of polishing slurries. For example, when a spherical lens made of fluorite (CaF2) is polished using a diamond slurry having a particle size distribution of 0.5 μm or less, surface processing error and sphericity required by the deep ultraviolet optical system: PV ≦ λ / 30 Surface roughness: rms ≦ 0.2 nm can be secured. The surface roughness is measured by a non-contact surface roughness measuring machine manufactured by Zygo. As a result, it is possible to polish a high-precision spherical lens having a radius of curvature tolerance on the order of μm, and in parallel with ensuring the curvature in optical design, it is possible to secure a surface processing error corresponding to the deep ultraviolet optical system.
[0056]
【Example】
FIG. 1 shows the basic structure of a spherical lens polishing tool, which is one embodiment of the present invention.
[0057]
The polishing tool base material 1a processed into a predetermined spherical shape is composed of a carbon resin, or a carbon resin material modified and reinforced by adding fine particles, fibers, etc. made of glass, metal, etc. The material 1a is provided with equally spaced lattice grooves 1b, and a pitch layer 2 having a thickness of 0.3 mm or less is formed on a small area 1c. As the processing order of the polishing tool base material, the processing error of R (curvature radius) is smaller when the groove processing is performed first and the spherical processing is performed last. When the depth of the grating groove 1b is larger than that of the small area 1c, the small rectangular column 1d is deformed during spherical processing, and the R processing error increases.
[0058]
FIG. 2 shows various variations of the spherical lens polishing tool base material shape.
[0059]
Polishing tool base materials that have been processed into a spherical surface for polishing various spherical lenses include a convex mold 3, a flat mold 4, a concave mold 5, and the like. Although not shown, there is a similar uneven surface mold as a polishing tool base material processed for cylindrical lens polishing. Further, although not shown in the drawing, a plurality of these tool base materials can be bonded or fastened as a segment on a large base and used as a large polishing tool.
[0060]
In addition to the lattice grooves, the polishing tool base material is provided with various grooves such as a radial groove 3a, a concentric groove, a spiral groove, and a free-curve groove (not shown). Although not shown, a tool of a type in which no groove is provided in the polishing tool base material may be used.
[0061]
3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8 show an example of a pitch layer forming process on the surface of the polishing tool.
[0062]
The pitch as the polisher material is liquefied beforehand with a solvent such as toluene and adjusted to an appropriate viscosity. When a high-viscosity dissolution pitch is applied on the polishing tool base material 5, a droplet-like form 2a is obtained. From this state, natural drying or forced drying using hot air is performed to evaporate the solvent, and the pitch material is appropriately cured. The pitch material that has been liquefied and re-cured by the solvent has lost its original hardness, and the effect of embedding the fine particles is increased, so that the surface roughness of the parts such as the lens to be polished becomes an ultra-smooth surface.
[0063]
The polishing tool 1 in the dry state after the pitch application is put into reverse contact with the mating tool 6 having a desired radius of curvature, and the polisher surface shape is adjusted. At this time, a weight may be applied after the contact, but since the pitch causes a creep phenomenon even at room temperature, it may wait for natural deformation. However, since the carbon resin has a large coefficient of thermal expansion, it is preferable not to heat for promoting shaping.
[0064]
When weighting is performed and shaping is performed for a short time, a surface active agent such as polyethylene glycol is applied to the surface of the pitch layer to facilitate separation after shaping. On the other hand, when shaping over a long time, it is preferable to sandwich a thin film material 7 between the surface of the pitch layer and the mating tool 6. In this way, when the two cannot be separated from each other after shaping, if they are cooled in a freezer, slippage occurs at the interface of the film layer due to the difference in thermal expansion coefficient between the two, and separation is easy.
[0065]
Further, the processing accuracy such as the sphericity and the radius of curvature of the matching tool 6 is appropriately adjusted according to the required specifications of the target lens.
[0066]
Although the surplus material spreads around the outer periphery of the pitch layer 2c immediately after shaping, it is made into a state 2b cut off with a cutter knife and used for polishing.
[0067]
FIG. 9 shows a basic structure when the polishing tool is mainly mounted on the lower shaft side of the polishing apparatus. In this case, a lens is mounted on the upper shaft side.
[0068]
Usually, the lower shaft side of the lens polishing apparatus is a rotating shaft, and is connected to the polishing tool by a screw or a collet chuck. A lower shaft holder of a mold that holds a part of the outer peripheral side surface from the back surface of the polishing tool base material 1a is indicated by 8a, and a bottom shaft holder of a flange type that is provided with a counterbore on the back surface of the polishing tool base material 1a and held from the center portion Is shown at 9a. The polishing tool base material and the lower shaft holder may be joined by an adhesive, but may be fastened by providing a screw on the back surface of the base material. Screws 8b and 9b are provided on the back surfaces of the holders, respectively. Although not shown, a collet chuck taper shaft may be provided for the convenience of the polishing apparatus.
[0069]
FIG. 10 shows a basic structure when the polishing tool is mainly mounted on the upper shaft side of the polishing apparatus. In this case, a lens is mounted on the lower shaft side.
[0070]
Normally, the upper shaft side of the lens polishing apparatus is a rocking shaft, and is connected to the polishing tool by a simple universal joint having a structure in which a spherically processed shaft end called “kanzashi” is inserted. A hole 10 may be provided directly in the center of the back surface of the polishing tool base material 1a, or a counterbore may be provided in the back surface of the polishing tool base material 1a, and a hole 12 may be provided to insert the shaft end of the Kanzashi. The upper shaft holder 11 may be joined with an adhesive or fastened with screws or the like. Further, a structure in which a flange-type member 11a made of a self-lubricating resin material is mounted inside the upper shaft holder 11 and a hole 12 for inserting a shaft end of a Kanzashi may be provided.
[0071]
Further, if the screw part size of the upper shaft holder 11 and the screw part size of the lower shaft holders 8a and 9a described in the basic structure when the polishing tool is mounted on the lower shaft side of the polishing apparatus are made common. By exchanging the holder, it can be mounted on both the upper shaft and the lower shaft of the polishing apparatus.
[0072]
In addition, a cylindrical member is mounted instead of the upper shaft side of the polishing apparatus, and the screws 8b and 9b on the back surface of the holder described in the basic structure when the polishing tool is mounted on the lower shaft side of the polishing apparatus are attached. When a rubber cap member 13 having a spherical surface R is put on and inserted into the inside of the cylinder, another kind of universal joint is formed, and equivalent polishing can be performed. Even in this structure, the polishing tool can be mounted on both the upper and lower shafts of the polishing apparatus. Become.
[0073]
FIG. 11 shows a state in which the radius of curvature of the polishing tool is corrected using an electrodeposited diamond wheel.
[0074]
The polishing tool 1 is mounted on the rotating lower shaft side of the polishing apparatus, the upper shaft side stops swinging, and a diamond electrodeposited cup wheel (also referred to as an electrodeposited diamond wheel or cup wheel) 14 is mounted. The diameter of the cup wheel 14 is suitably 60 to 80% of the diameter of the polishing tool 1. In this example, a flange-type member 15 made of a self-lubricating resin material is mounted on the upper part of the cup wheel 14, and the shaft end of the Kanzashi 16 is inserted into the hole 15a so that the cup wheel 14 can be freely rotated. Yes. When the lower shaft of the polishing apparatus is rotated in this state, the cup wheel 14 also starts to rotate due to friction with the polishing tool 1 and the pitch layer on the surface of the polishing tool is ground and removed.
[0075]
Here, when the position of the upper shaft of the polishing apparatus is operated and the position of the cup wheel 14 is shifted to the center side of the polishing tool 1 and is stopped, the center portion of the polishing tool is relatively worn down. When the position is shifted to the outer peripheral side of the polishing tool 1 to be stationary, the outer peripheral portion of the polishing tool is relatively worn out.
[0076]
FIG. 12 shows a shift state of the position of the cup wheel 14. The cup wheel adjusts the curvature radius R in accordance with the uneven shape of the polishing tool. For example, if the polishing tool 1 is a convex surface, R is decreased when the position of the cup wheel 14 is shifted to the outer peripheral portion, and the curvature radius R is increased when the position is shifted to the central portion.
[0077]
Further, if the lower shaft side is tilted by the structure of the polishing apparatus, the inclination of the polishing tool 1 may be changed in order to change the relative positional relationship between the polishing tool 1 and the cup wheel 14.
[0078]
FIG. 13 shows a state in which the cup wheel 14 easily rolls over when the polishing tool 1 has a concave shape.
[0079]
As can be seen from FIG. 14, this phenomenon occurs when the concave polishing tool 1 rotates, and the frictional force F acts as a fulcrum at the contact point P on the outer peripheral side in the intrusion direction of the cup wheel 14. This is because it acts as a rotation (falling) moment Mc to K. Mc = f · Lc, Lc is a distance between P-K, and f is a component force of the frictional force F in a direction orthogonal to the P-K direction. R of the concave-shaped tool 1: The smaller the radius of curvature, the deeper the pitch layer digs into the cup wheel 14, and the result F (f) increases and rolls easily. Further, if the position of K is high, Lc increases and f component force increases, so that it is very easy to roll over.
[0080]
On the other hand, as can be seen from FIG. 15, in the case of a convex-shaped polishing tool, the frictional force F with the rotation of the polishing tool 1 causes the axial end of the Kanzashi 16 with the contact point P on the inner peripheral side in the intrusion direction of the cup wheel 14 as a fulcrum. A rotational moment Mx acts on the portion K. Mx = f · Lx, Lx is a distance between P-K, and f is a component force of the frictional force F in a direction orthogonal to the P-K direction. However, f in this case acts not in the direction of lifting the cup wheel 14 but in the direction of grounding to the polishing tool side, and works for stabilization. R of the convex shaped tool 1: The smaller the radius of curvature, the deeper the pitch layer digs into the cup wheel 14, and the result F (f) increases and the cup wheel 14 becomes more stable. Further, if the position of K is high to some extent, Lc increases and f component force increases and stabilizes, but on the other hand, the cup wheel 14 bites deeply and causes excessive wear of the pitch layer. If the angle further exceeds, the point Q on the opposite side of P will fall over the fulcrum, so it is better to adjust appropriately.
[0081]
FIG. 16 shows an example of the rollover prevention device (auxiliary device) of the concave polishing tool 1. The cup wheel 14 on the polishing tool 1 is held freely rotated by a Kanzashi 16. When two or more horizontal guide rollers 18 come into contact with the side surface of the cup wheel 14, the rotational moment is canceled. The horizontal guide roller 18 is freely rotated and held by a horizontal plate 17a provided with a rotation axis vertically. The horizontal plate 17a is connected to the arm 17 drawn out from an arbitrary component of the polishing apparatus.
[0082]
FIG. 17 is also another example of the rollover prevention device (auxiliary device) of the concave polishing tool 1. The cup wheel 14 on the polishing tool 1 is held freely rotated by a Kanzashi 16. When one or more vertical guide rollers 19 come into contact with the upper surface of the cup wheel 14, the rotational moment is canceled. The vertical guide roller 19 is freely rotated and held by an arm 17 having a horizontal rotation shaft. The arm 17 is pulled out from any constituent member of the polishing apparatus.
[0083]
Although FIG. 16 and FIG. 17 described that the arm 17 is pulled out from an arbitrary component of the polishing apparatus, workability is good if the arm 17 is integrated with the polishing apparatus from the beginning. An independent polishing tool curvature correcting device may be used.
[0084]
The polishing tool curvature correction work by the above apparatus is performed for about 30 to 60 seconds at a low rotation of 3 to 10 rpm, and the pitch chips on the surface of the polishing tool are cleaned and used for lens polishing. Changes in the radius of curvature of the lens surface that occurs after polishing for a certain period of time are measured and observed using a prototype, a laser interferometer, etc., and the difference from the target radius of curvature tolerance is checked. The lens curvature radius is guided to the required specifications.
[0085]
The polishing tool adapts to various types of polishing slurries. For example, when a spherical lens made of fluorite (CaF2) is polished with a diamond slurry having a particle size distribution of 0.5 μm or less, it is required for a deep ultraviolet optical system. Surface processing error, sphericity: PV ≦ λ / 30, surface roughness: rms ≦ 0.2 nm could be secured.
[0086]
Further, in the case of a convex lens, the lens curvature radius error when the polishing tool is used as it is is only about 0.037% (13 to 26 μm) of the curvature radius R when 35 mm ≦ R ≦ 70 mm. The tool curvature correction method enables polishing of a high-precision spherical lens having a curvature radius tolerance of about 0.005 to 0.010% (2.5 to 5 μm), that is, μm order.
[0087]
The upper shaft and the lower shaft are not limited to the rotation shaft, and may be a swing shaft or the like.
[0088]
【The invention's effect】
According to the first aspect of the present invention, since the carbon resin material is used as the base material, sufficient time to extend the tool life while maintaining the shape stability, improve the shape accuracy, and simultaneously reduce the surface roughness. Can be ensured, and the wound of the polishing strip can be prevented. Since the carbon resin is inherently soft and tends to adsorb abrasive grains, even when exposed to the surface due to abrasion of the pitch layer, damage to the surface of the counterpart component is extremely small.
[0089]
In addition, by using a carbon resin material as a base material, it is possible to easily perform curved shape processing and free grooving using general-purpose NC lathes and machine tools, and have a wide variety of shapes and groove structures. A polishing tool can be realized.
[0090]
Carbon resins are also advantageous in that they are less likely to corrode in various types of polishing liquids that exhibit acidity and alkalinity, and are difficult to crack in handling and work.
[0091]
According to the second aspect of the present invention, since the thickness of the pitch layer is 0.3 mm or less, the viscoelasticity is small and the edge does not easily occur.
[0092]
According to the invention of claim 3, since the surface of the carbon resin material is processed into a predetermined shape and provided with grooves, optical members having various shapes can be polished.
[0093]
According to the invention of claim 4, since the carbon resin material is modified or reinforced, the performance of the polishing tool can be improved.
[0094]
According to the invention which concerns on Claim 5, since the several carbon resin material segmented is adhere | attached on the rigid board | substrate of a metal or a ceramic, a polishing tool can be enlarged.
[0095]
According to the invention which concerns on Claim 6, since the pitch layer is formed by drying after apply | coating the liquefied pitch, a polishing tool can be manufactured easily.
[0096]
According to the invention of claim 7, since the pitch is liquefied with the solvent and then the pitch is re-cured, the effect of burying the abrasive grains is increased, and an ultra-smooth optical surface can be obtained.
[0097]
According to the eighth aspect of the present invention, since the base material made of the carbon resin material is formed into a predetermined shape and then the liquefied pitch is applied to the surface of the carbon resin agent, the processing error of the polishing tool can be reduced.
[0098]
According to the ninth aspect of the invention, since the pitch layer is formed by a predetermined process, the effect of burying the fine particles is increased, and the surface roughness of the parts such as the lens to be polished becomes an ultra-smooth surface.
[0099]
According to the inventions according to claims 10 and 11, since the polishing tool is mounted on either the upper shaft or the lower shaft of the polishing apparatus, or is configured to be mounted on both, it is applied to various polishing apparatuses. it can.
[0100]
According to the twelfth aspect of the present invention, since the polishing tool is mounted on one of the upper shaft and the lower shaft and the electrodeposited diamond wheel is mounted on the other shaft, the radius of curvature of the polishing tool can be easily corrected.
[0101]
According to the invention of claim 13, since the distance between the upper shaft and the lower shaft is relatively variable, the curvature radius of the polishing tool can be corrected in the μm order, and the curvature radius allowable error in the μm order. It is possible to polish a high-precision spherical lens having
[0102]
According to the invention which concerns on Claim 14, 15, since a curvature correction apparatus has an auxiliary | assistant apparatus, the fall of an electrodeposited diamond wheel can be prevented.
[0103]
According to the sixteenth aspect of the present invention, since the polishing apparatus includes the curvature correcting apparatus, the apparatus cost can be reduced and the workability can be improved.
[Brief description of the drawings]
FIG. 1 shows a basic structure of a spherical lens polishing tool which is one embodiment of the present invention.
FIG. 2 shows various variations of a spherical lens polishing tool base material shape.
FIG. 3 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 4 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 5 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 6 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 7 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 8 shows a part of a step of forming a pitch layer on the surface of the polishing tool.
FIG. 9 shows a basic structure when a polishing tool is mainly mounted on the lower shaft side of the polishing apparatus.
FIG. 10 shows a basic structure when a polishing tool is mainly mounted on the upper shaft side of a polishing apparatus.
FIG. 11 shows a state in which the radius of curvature of the polishing tool is corrected using an electrodeposited diamond wheel.
FIG. 12 shows a shift in the position of the cup wheel.
FIG. 13 shows how the cup wheel easily rolls over when the polishing tool has a concave shape.
FIG. 14 shows how the cup wheel easily rolls over when the polishing tool has a concave shape.
FIG. 15 shows how the cup wheel is stabilized when the polishing tool has a convex shape.
FIG. 16 shows an example of an auxiliary device for a concave polishing tool.
FIG. 17 shows another example of an auxiliary device for a concave polishing tool.
[Explanation of symbols]
1 Polishing tool
1a Abrasive tool base material
1b Lattice groove
1c Small area
1d small square pillar
2 Pitch layer
2a Droplet form
2b State cut off with a cutter knife
2c Pitch layer immediately after shaping
3 Convex type
3a Radial groove
4 Plane type
5 Concave type
6 Alignment tool
7 Film material
8a, 9a Lower shaft holder
8b, 9b screw
10, 12, 15a hole
11 Upper shaft holder
11a Flange type member
13 Cap material
14 Electroplated diamond wheel
15 Flange type member
16 Kanzashi
17 arms
17a horizontal plate
18 Horizontal guide roller
19 Vertical guide roller

Claims (12)

In the polishing tool for optical materials, the base material is composed of a carbon resin material, a pitch layer composed of pitch is formed on the surface of the carbon resin material constituting the base material, and the thickness of the pitch layer is 0.3 mm or less, the lower limit is 0.05 mm, and the pitch is a pitch that is liquefied with a solvent and loses its original hardness, that is, a pitch in which molecular chains of chain polymer hydrocarbons are broken , and A polishing tool , wherein the liquefied pitch is dried to a predetermined hardness .   The surface of the carbon resin material is processed into one of a spherical surface, a flat surface, and a cylindrical surface, and the lattice, concentric, radial, and spiral grooves are formed on the surface of the carbon resin material. The polishing tool according to claim 1, wherein the polishing tool is formed in a predetermined pattern.   The polishing tool according to any one of claims 1 to 2, wherein the carbon resin material is modified or reinforced by addition of fine particles or fibers containing glass or metal.   The polishing tool according to any one of claims 1 to 3, wherein a plurality of segmented carbon resin materials are bonded onto a metal or ceramic rigid substrate. A base material composed of a carbon resin material is molded into a predetermined shape, and then a pitch layer having a thickness of 0.3 mm or less and 0.05 mm or more is formed on the surface of the carbon resin material constituting the base material. The pitch constituting the pitch layer is a pitch that has been liquefied with a solvent and has lost its original hardness, that is, a pitch in which the molecular chains of the chain polymer hydrocarbons are broken , and the liquefied pitch is dried. A method for producing a polishing tool, characterized by having a predetermined hardness .   A polishing apparatus for an optical material in which an upper shaft and a lower shaft are arranged to face each other, the polishing tool according to any one of claims 1 to 5 is mounted on one of them, and the optical material is mounted on the other .   The upper shaft and the lower shaft are arranged to face each other, and the polishing tool according to any one of claims 1 to 5 is mounted on one of them, and an electrodeposited diamond wheel is mounted on the other. Curvature correction device.   8. The curvature correcting device according to claim 7, wherein the distance between the upper shaft and the lower shaft is relatively variable according to the shapes of the polishing tool and the electrodeposited diamond wheel.   The curvature correcting device according to claim 7 or 8, further comprising an auxiliary device including two or more guide rollers that are in contact with a side surface of the electrodeposited diamond wheel.   The curvature correcting device according to claim 7 or 8, further comprising an auxiliary device including a guide roller that comes into contact with an upper surface of the electrodeposited diamond wheel.   A polishing apparatus comprising the curvature correcting device according to any one of claims 8 to 10. Liquefaction with inorganic compound solvent,
Apply a pitch adjusted viscosity to the surface of the base material to form a pitch layer,
Perform natural drying or forced drying using hot air,
It is a method for forming a pitch layer for an abrasive tool that is vaporized and cured moderately,
The thickness of the pitch layer is 0.3 mm or less, 0.05 mm or more,
A method for forming a pitch layer for a polishing tool, wherein the pitch is a pitch that has been liquefied with a solvent and has lost its original hardness, that is, a pitch in which molecular chains of chain polymer hydrocarbons are broken.

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