JP2009107089A - Lens holder and curved surface polishing method for lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens holder surely preventing edge sagging in polishing, improving a quality, and shortening a polishing time, and also to provide a polishing method for a lens using the holder. <P>SOLUTION: A lens holder 2 is constituted of: a metal holder 3 blocking a center part of a convex surface 1b of a lens 1; and low melting point wax 4 blocking an outer periphery part of the convex surface 1b. The low melting point wax 4 is constituted of: a wax main body part 4A blocking the outer periphery part of the convex surface 1b of the lens 1; and an annular extension part 4B extending outwardly from the wax main body part 4A and blocking an outer periphery of the lens 1. In polishing, a surface 6' of the extension part 4B of the wax 4 is polished to a curved surface identical or approximate with a concave surface 1a peripheral part of the lens 1, and the extension part 4B is left. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens holder and a method for polishing a curved surface of a lens that are used when a spectacle lens is polished.

  When polishing the concave surface of the spectacle lens, using known methods such as hand polishing, polishing using an elastic member, small tool method, EEM (Elastic Emission Machining), MRF (Magnet-Rheological Finishing), etc. For example, polishing is performed using a general-purpose polishing apparatus (TORO-X2SL) manufactured by Satis Loh, which is generally commercially available. In this polishing apparatus, the lens is blocked (held) by a lens holder, the polishing pad is pressed against the concave surface of the lens with a predetermined pressure, the polishing pad is swung in this state, the lens is rotated, and the front, rear, left and right are rotated. By reciprocating in the direction, the concave surface of the lens is polished by the polishing pad and the abrasive with a trackless polishing locus in which the polishing locus is slightly shifted every round (see, for example, Patent Document 1).

  A lens holder for blocking a lens generally includes a metal yatoi, and the lens and the lens are joined by a low melting point alloy (alloy). When the lens is blocked by the lens holder, a protective film for preventing scratches is brought into close contact with the convex surface of the lens in advance. Next, a yatoy is installed on the mounting base, the periphery thereof is surrounded by a blocking ring, and a lens having the protective film in close contact with the ring is placed with its convex surface down. Thereby, the blocking ring supports the convex outer peripheral edge of the lens by the upper surface side inner peripheral edge. Then, the molten low melting point alloy is poured into a space surrounded by the lens, the yatoy, the blocking ring, and the mounting base, and solidified by pouring the molten low melting point alloy.

  By the way, when the lens is polished with a polishing pad, a part of the polishing pad jumps out from the outer periphery of the processing surface at the peripheral portion, so that the polishing pad is deformed and the pressure on the processing surface becomes non-uniform, Polishing residue due to contact of the polishing tool or the like, and dripping (hereinafter referred to as edge dripping) occur at the peripheral edge of the surface to be processed. As a result, there have been problems such as spending more polishing time than necessary to eliminate polishing residue and reducing the shape accuracy of the surface to be processed. As a method of compensating for the decrease in shape accuracy, the processed surface before polishing is processed using the polishing correction amount, and it takes several months to obtain this.

  In order to solve such problems, for example, a lens holder and a polishing method disclosed in Patent Documents 2 to 5 are known.

  Patent Document 2 discloses a polishing having an inclined surface shape that is the same as or close to the tangent to the peripheral edge of the work surface of the work piece in order to prevent a reduction in shape accuracy due to the so-called edge of the work piece. A Yatoi is attached to the outer periphery of the work piece for polishing. As a yatoy, a glassy yato made of steel or the same quality as a lens is used.

  Patent Document 3 discloses a first polishing step in which a dummy (Yatoi) is fitted on the outer periphery of a work made of optical components such as a lens and a prism, and the dummy and the surface of the work are polished. And a second polishing step for polishing the outer peripheral edge of the workpiece in anticipation of a processing step generated at the boundary between the dummy and the workpiece by the first polishing step. It is carried out in at least one of the pre-process and post-process of the first polishing process. A dummy made of the same material as the workpiece is used as the dummy.

  In Patent Document 4, similar to Patent Documents 2 and 3, the outer periphery of the processed surface is filled with a deformable slipping member, and the processing surface and a single curved slipping surface are formed on the surface of the slipping member. A single curved surface that is created and surrounded by the blank surface is polished by a polishing jig. As the blank member, an ultraviolet curable resin or a low melting point alloy is used.

  Patent Document 5 uses a low-melting-point alloy or a high-viscosity low-melting-point wax as a bonding agent for integrally bonding lens blanks to Yatoi.

JP 2003-334748 A JP 2001-045662 A JP 2007-000989 A JP 2002-326148 A Japanese Patent Laid-Open No. 2005-230985

  However, since Yaito described in Patent Documents 2 and 3 is made of steel or glass, it cannot be reused once used for polishing (because the curved surface differs for each lens), and the material is wasted. There is a problem that it increases and contributes to an increase in manufacturing cost. In addition, because Yatoi is formed in a ring shape that surrounds the outer periphery of the lens, it is difficult to accurately block the outer periphery of the workpiece if the workpiece has almost no edge thickness. There has also been a problem that the axis of the object is inclined with respect to the axis of the yatoy, or a step is formed between the peripheral edge of the work surface and the inner edge of the inclined surface of the yato.

  The polishing method described in Patent Document 4 has a problem in that it cannot be reused when an ultraviolet curable resin is used as a whitening material. Similarly to Patent Documents 2 and 3 described above, the slip-off member is formed in an annular shape and the outer periphery of the lens is blocked. Therefore, as in Patent Documents 2 and 3, the lens must have a certain edge thickness. There is a problem that it is difficult to apply.

  Patent Document 5 has a problem that edge fringing occurs because only a low-melting-point wax is used as a bonding agent between a lens and a yatoi, and no measures are taken for edge fringing during polishing.

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to surely prevent edge dripping during polishing, and to improve quality and shorten polishing time. Another object of the present invention is to provide a lens holder and a lens polishing method using the same.

  In order to achieve the above object, a lens holder according to the present invention has a metal holding part that blocks the central part of the convex surface of the optical lens before polishing and a low melting point that blocks the outer peripheral part of the convex surface of 60 to 80 ° C. The low melting point wax is integrally provided with an annular extension that blocks a part of the outer periphery and convex surface of the optical lens.

  Further, in the lens holder according to the present invention, the radial length of the extension portion of the low melting point wax is 0.5 mm or more, and the surface height is substantially equal to the outer peripheral edge height of the concave surface of the lens before polishing. It is polished to a curved surface that is the same as or close to the peripheral edge of the concave surface.

  Further, the lens polishing method according to the present invention includes a step of blocking the central portion of the convex surface of the optical lens before polishing through a low melting point alloy with a metal holding portion, and a melting point of 60 between the outer peripheral portion and the edge surface of the convex surface. A portion extending to the outside of the edge of the low melting point wax when the concave surface is polished, comprising a step of blocking with a low melting point wax of ˜80 ° C. and a step of polishing the concave surface of the lens into a predetermined curved surface Is polished to a curved surface that is the same as or close to the peripheral edge of the concave surface.

In the present invention, a low melting point wax that blocks the outer peripheral portion of the convex surface of the lens is provided, and an annular extension that blocks the outer periphery of the lens is provided integrally with the wax. Can be polished together.
Further, since the low melting point wax holds the convex surface of the lens together with the metal holding portion, the lens can be easily blocked and processed even with a lens having no edge thickness (for example, a part of a plus lens).

  The low melting point wax is easy to cool and solidify and can be molded in a short time (about 15 minutes at room temperature), and can be reused by melting and molding after polishing. In addition, wax is easy to mold, can be processed with high accuracy, and can be used for lenses of various shapes.

Further, the radial length of the extended portion of the low melting point wax is 0.5 mm or more, the surface height is substantially equal to the outer peripheral edge height of the concave surface of the lens before polishing, and is the same as the peripheral edge portion of the concave surface during polishing or Since the surface is polished to an approximate curved surface, the outer peripheral portion of the concave surface of the lens and the surface of the extension portion can be pressed and polished with a substantially uniform pressure. Therefore, the deformation of the polishing pad is uniform and no edging occurs, and the shape accuracy of the surface to be processed can be improved.
Further, when polishing the peripheral portion, if the polishing amount is partially controlled so as not to cause edge fringing, the time required for the polishing time becomes longer. Since the surfaces are formed in substantially the same curved surface, it is not necessary to adjust the polishing amount, and the polishing time can be shortened.

  If the length of the extension in the radial direction is 0.5 mm or less, the polishing pad will be deformed (distorted), etc., resulting in uneven pressure and poor contact. It is not preferable. The length in the radial direction of the extension before polishing may be as long as it is 0.5 mm or more, but it is common knowledge that it depends on the adhesion and shrinkage of the wax to the workpiece and the edge of the workpiece or polishing tool. Although it is difficult to grind the outer peripheral part of the workpiece (in the range of about 3 to 4 mm from the outer peripheral part) due to twisting or the like, the problem can be solved by setting the length of the extension part in the radial direction to 0.5 mm or more. Moreover, although depending on the amount of unpolished left part of the outer peripheral part and the cooling of the wax, the length in the radial direction of the extension part is preferably 0.5 to 10 mm, more preferably 3 to 5 mm when considering production efficiency. preferable.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view showing a state in which a positive lens before processing is blocked by a lens holder according to the present invention, and FIG. 2 is a cross-sectional view after polishing. 1 and 2, the present embodiment shows an example applied to the case where the concave surface 1a of the lens 1 made of a plus lens is polished. The lens 1 to be polished is made of plastic made of urethane or epithio resin having a high refractive index (n = 1.55 to 1.75), and the convex surface 1b is finished to a predetermined optical surface. A semi-finished lens was used.

  When the concave surface of the lens 1 shown in FIGS. 1 and 2 is polished, a lens holder 2 is used. The lens holder 2 is composed of two members, a metal holder 3 and a wax 4. The metal holding part 3 is an alloy (low-melting-point alloy) that is interposed between the Yatoi 3A made of metal such as SUS303 and the Yatoi 3A and the convex surface 1b of the plus lens 1 to join the lens 1 and the Yatoi 3A. ) 3B. The yatoy 3A is a portion that is prevented from rotating and is detachably fitted into a fitting recess 12 of the rotating shaft 11 of the polishing apparatus 30 described later. As the alloy 3B, a known material such as a mixture of tin, indium, bismuth and the like can be used. The alloy 3B is formed in a disk shape that is smaller than the outer diameter of the lens 1 and larger than the outer diameter of the yatoy 3A, and the surface that contacts the convex surface 1b of the lens 1 forms the lens holding surface 5, and the center of the convex surface 1b of the lens 1 It is joined to. For this reason, the lens holding surface 5 forms a concave surface having substantially the same radius of curvature as the convex surface 1b. The reason for using the metal yatoy 3A having a high mechanical strength as the metal holding part 3 that blocks the central part of the convex surface of the lens 1 is to prevent deformation due to a load during polishing. When the heated and melted alloy 3B is poured into the gap between the lens 1 and the metal holder 3, the convex surface 1b of the lens 1 is supported by a blocking ring described later so that the alloy 3B does not leak outside the blocking ring.

  As the wax 4, a low melting point wax is used. The wax 4 includes an annular wax main body 4A that blocks the outer side of the convex central portion of the convex surface 1b of the lens 1 that is blocked by the alloy 3B of the metal holding portion 3, and extends outside the wax main body 4A. And an annular extension 4 </ b> B that blocks the outer periphery of the lens 1. As shown in FIG. 1, the surface 6 of the extension 4B is preferably substantially the same height as the outer peripheral edge tip 1c of the lens concave surface 1a of the lens 1 before polishing. As shown in FIG. 2, the extended portion 4B is polished so that the surface is polished to a curved surface 7 that is the same as or close to the peripheral edge of the processed concave surface 1d. The position may be higher or lower than the peripheral edge tip 1c.

  The length L in the radial direction of the extension 4B is 0.5 mm or more, and the height H from the alloy 3B is not particularly defined, but is preferably 8 mm or more in terms of strength. The reason why the length L in the radial direction is 0.5 mm or more is that when the peripheral portion of the concave surface 1a of the lens 1 is polished by the polishing pad 19, the polishing surface of the polishing pad 19 is substantially the same curved surface as the curved surface of the peripheral portion. If formed, when the peripheral portion of the concave surface 1a and the surface 6 of the extension 4B are simultaneously polished by the polishing pad 19, the deformation of the polishing pad 19 is small on the concave surface 1a, and the applied pressure to the concave surface 1a becomes uniform, This is because the occurrence of edge fringing can be prevented and the concave surface 1d formed of a predetermined curved surface can be obtained. If the thickness is 0.5 mm or less, the deformation of the polishing pad 19 is increased, and edge fringing occurs. In the case of a lens made of a material other than plastic such as glass, in the case of an example made of glass, the hardness H is higher than that of a plastic lens, so that the height H of the extension 4B can be lowered to about 4 mm. is there. In FIGS. 1 and 2, the wax 4 is in close contact with the outer periphery of the alloy 3B. However, this is not always necessary, and an appropriate annular gap 13 may be provided as shown in FIG. FIG. 3 shows an example of polishing the concave surface of a normal minus lens 1 ″ having an edge thickness T after polishing, and the lens holder 2 itself is exactly the same.

  The wax 4 is not particularly limited, and a publicly known substance can be used. For example, natural waxes such as carnauba wax, rice wax, candelilla wax, waxes such as tree wax, animal waxes such as spermaceti, lanolin and beeswax, mineral waxes such as montan wax, ceresin and ozokerite, paraffin wax And petroleum waxes such as microcrystalline wax and petrolatum. In addition, synthetic hydrocarbons such as polyethylene, Fuscher-Tropsch wax, etc., montan wax derivatives, microcrystalline wax derivatives, paraffin wax derivatives (modified groups such as carboxy-modified, amino-modified, alcohol-modified, ester, etc.) Examples thereof include hydrogenated waxes such as wax, hardened castor oil, hardened castor oil derivatives, and the like, and these can be used alone or in combination. Among these, paraffin wax, polyethylene wax and the like are preferably used in consideration of workability, ease of shape formation, and cost.

In the present embodiment, an example in which a highly viscous wax (preferable use temperature of 60 to 80 ° C.) is used as the low melting point wax 4 will be described. The wax 4 is a blend mainly composed of polyethylene wax, for example, and the main component is hydrocarbon. The physical properties of the wax are insoluble in water with a softening point of 57 ° C., an application point of 300 ° C., a density of 0.92 g / cm ² (25 ° C.), and a viscosity of 330 mPa / s (100 ° C.).

Next, the polishing procedure for the lens 1 will be described.
4A to 4F are views for explaining the lens holding and polishing steps by the lens holding portion.
First, a lens 1 having a concave surface 1a is prepared (FIG. 4A). Next, the protective film 8 is stuck on the convex surface 1b of the lens 1 (FIG. 4B).

  The protective film 8 is used for preventing the convex surface 1b of the lens 1 from being scratched and for facilitating the removal of the lens holder 2 after polishing. For example, a surface layer, an intermediate layer, an adhesive layer The surface layer and the intermediate layer are made of polyethylene and the adhesive layer is made of polyolefin. The thickness of each layer is about 10 μm for the surface layer, 85 μm for the intermediate layer, and about 25 μm for the adhesive layer. The physical property of the protective film 8 is a film-like solid at room temperature, and may have a two-layer structure of a base material layer made of polyethylene and an adhesive layer made of polyolefin. Its physical properties are film-like fixation at normal temperature, melting point is 110 to 130 ° C., and specific gravity is 0.9 to 1.0. Conventionally, the protective film 8 is used for securing the workpiece and ensuring close contact with the alloy. However, in the case of extrapolated wax, since the close contact with the workpiece can be sufficiently secured, the present invention mainly uses the workpiece. Used to prevent scratches.

  Next, the convex surface 1b of the lens 1 is held by the alloy blocking ring 14 to which the Yatoi 3A is attached. As a result, a space 15 is formed between the convex surface 1b, the yatoy 3A and the blocking ring 14 (FIG. 4 (c)). When the molten alloy 3B is poured into the space 15 and solidified (FIG. 4 (d)). The lens 1 is joined to the Yatoi 3A via the alloy 3B. In other words, the lens 1 is blocked by the metal holder 3.

  Next, after the alloy 3B is solidified, the blocking ring 14 is removed, and the lens 1 in which the Yatoi 3A is bonded to the wax blocking ring 16 having a larger outer diameter via the alloy 3B is attached. And the wax 4 melted in the space formed by the outer periphery of the alloy 3B and the inner periphery of the blocking ring 16 until the outer periphery height of the lens 1 is filled and solidified, and the lens 1 is blocked by the wax 4 (FIG. 4 ( e)).

  When filling the wax 4, the solid wax is directly heated and melted by a heater, and when the melted wax reaches about 80 ° C., it is poured using a nozzle or the like.

  The melting point of the wax 4 can be used without any particular problem as long as it does not melt at room temperature. In particular, it is preferable to use a low melting point wax 4 having a melting point of 60 to 80 ° C. Although the hardness of the wax 4 is not particularly specified, it is preferable to select a material softer than the work material in order to reduce damage to the polishing pad 19 due to the edge of the work and to suppress the wear of the pad itself as much as possible.

  The best effect of extrapolation wax is to move the part of the outer periphery of the workpiece that is left unpolished (points from 3 to 4 mm from the outer periphery) to the extrapolated part of the workpiece. Known abrasives such as alumina, silica, zirconia, ceria, manganese oxide, and diamond can be added to the extrapolated wax, but in the case of plastic lenses, it is preferable to use alumina. When the lens 1 is blocked by the lens holder 2, for example, the lens 1 is blocked using a device called a layout blocker manufactured by Satislaw Co., Ltd. described above. Further, blocking with the Yatoi 3A and the alloy 3B and the wax 4 is performed in descending order of the melting points of the alloy 3B and the wax 4.

  After the wax 4 is solidified, the blocking ring 16 is removed, the lens 1 is mounted on the polishing apparatus, and the concave surface 1b is polished to a predetermined curved surface by the polishing pad 19 (FIG. 4 (f)).

Next, the polishing apparatus 30 used for polishing the spectacle lens 1 will be described.
In FIG. 5, a polishing apparatus 30 is used for polishing the concave surface 1 a of the lens 1 (see, for example, Patent Document 6). An arm 33 that is movable in the left-right direction on the paper surface and is rotatable about a horizontal axis 32 in a direction orthogonal to the paper surface, and a direction that reciprocates the arm 33 in the left-right direction and that is orthogonal to the paper surface. A driving device that is not shown in the figure, a lens mounting portion 34 that is provided on the arm 33 and blocks the convex surface 1b of the lens 1 via the lens holder 2, and is located below the lens mounting portion 34. And a swinging device 35 that swings (does not rotate) around a vertical axis K by a driving device (not shown). Further, a polishing jig 36 detachably provided on the swing device 35, a polishing pad 19 detachably attached to the polishing jig 36, and a lens attaching portion 34 installed on the arm 33 are moved up and down. Elevating device 37 and the like are provided.

JP 2003-266287 A

  The oscillating device 35 is inclined and attached to a vertical rotating shaft 38 so as to swing and swing at an oscillating angle α (for example, 5 °), and the polishing jig 36 is installed on the upper surface.

  The polishing jig 36 has a balloon member 39 (FIG. 1) formed of an elastic material such as natural rubber, synthetic rubber, or rubber-like resin, and closes the back opening of the balloon member 39 to block the inside airtightly. A fixing member (not shown) and a valve or the like provided on the fixing member are provided, and the balloon member 39 is used in an inflated state by supplying compressed air into the balloon member 39 through the valve. It is configured as follows. The balloon member 39 is formed in an elliptical cup shape, and a surface portion 39A that contacts the concave surface 1a of the lens 1 is a flat or gently convex curved surface. It is configured to be deformed into a dome shape having a curvature radius substantially equal to the concave surface 1a. As the material of the balloon member 39, for example, synthetic rubber (for example, IIR) or natural rubber close to natural rubber having a hardness of 20 to 50 degrees is used. The thickness of the balloon member 39 is uniform throughout and is about 0.5 to 2 mm (usually equal to about 1 mm). It is preferable to prepare a plurality of types of balloon members 39 according to the size of the lens 1 to be polished and the shape of the surface to be polished.

  The polishing pad 19 used for polishing the concave surface 1a of the lens 1 is formed of a sheet material having a thickness of about 1 mm made of, for example, a fibrous cloth such as foamed polyurethane, felt, or nonwoven fabric, or a synthetic resin. The balloon member 39 is formed in an oval shape having substantially the same size as the front view of the dome portion 39A. For example, eight fixing pieces 19a are extended on the periphery, and these fixing pieces 19a are formed as balloon members. It is detachably fixed by a fastening member 40 which is bent along the outer periphery of 39 and is formed of a wire spring having an appropriate thickness.

  In order to attach the polishing pad 19 to the balloon member 39, first, the dome portion 39A of the balloon member 39 is expanded into a predetermined dome shape by supplying compressed air, and then the polishing pad 19 is placed thereon. Next, the fixing piece 19a is bent along the outer periphery of the balloon member 39, and the fastening member 40 is fitted on the outer periphery of the balloon member 39 to press and fix the fixing piece 19a.

  The lens 1 is polished by the polishing apparatus 30 having such a structure according to the following procedure. First, the lens holder 2 that blocks the lens 1 is attached to the lens mounting portion 34 of the arm 33. Next, a polishing jig 36 that blocks the polishing pad 19 is installed on the upper surface of the swing device 35, and the lens 1 is lowered by the lifting device 37 to press the concave surface 1 a against the surface of the polishing pad 19. In this state, the abrasive is supplied to the surface of the polishing pad 19 and the swinging device 35 is swung and swung while the arm 33 is reciprocated in the left and right and front and rear directions. By these movements, the concave surface 1a of the lens 1 is polished by the polishing pad 19 and the abrasive with a trackless polishing locus in which the polishing locus is slightly shifted every round, and finished to a desired curved surface. The polishing is generally about 5 to 15 μm although it depends on the surface properties of the processed surface. As the abrasive, for example, a solution in which an abrasive (abrasive grains) such as alumina and diamond powder is dispersed in a polishing liquid is used.

  In polishing, rough polishing is performed using an abrasive having an average particle diameter of 1.6 to 1.8 μm. Thereafter, the polishing pad 19 is further replaced with a new one, and finish polishing is performed using an abrasive having an average particle diameter of about 0.8 μm to make the concave surface 1a a predetermined optical surface.

  When the polishing of the lens 1 is finished, visual inspection, power inspection with a lens meter, projection inspection of the inner surface of the lens with transmitted light of a zircon lamp and optical performance inspection for astigmatism are performed, and the manufacturing of the lens 1 is completed.

  As described above, in the lens holder 2 according to the present invention, the outer peripheral portion of the convex surface 1b of the lens 1 is held by the wax 4, and the extended portion 4B that blocks the outer periphery of the lens 1 is integrally provided on the wax 4. When the concave surface 1a is polished, the extended portion 4B is polished together, so that the outer peripheral portion of the concave surface 1a and the extended portion 4B of the wax 4 form a curved surface that is substantially the same or approximate. As a result, the polishing pad 19 is not deformed in the vicinity of the outer peripheral portion of the concave surface 1a, and a substantially uniform pressure can be applied to the lens 1. Therefore, it is possible to reduce the time required for processing the peripheral portion of the concave surface 1a many times so as not to bend, to reduce the processing time, and to prevent generation of a defective product due to the edge, and to produce a lens having a good quality. Can be manufactured. Further, since the wax 4 blocks the convex surface 1b of the lens 1 together with the metal holding portion 3, it can be easily processed even with the lens 1 having no design edge thickness.

  Further, depending on a polishing object such as glass or metal material, it can be applied to polishing of a convex surface or a flat surface.

  Also, it is not necessary to create and store various types of waxes 4 according to the processing curved surface. In addition, it has good adhesion to the lens 1 and is easy to cool and solidify and can be molded in a short time (about 15 minutes at room temperature) and can be processed with high precision. It can be easily removed from the lens 1 by heating for about a minute. After further removal, the wax 4 is diluted with a solvent together with the chips of the wax 4, heated and melted, and then removed by removing volatile components. The consumption of 4 is small and economical.

  Furthermore, since the wax 4 is not included in the substances stipulated in the Chemical Substance Examination Regulation Law, the wax 4 can be used with confidence without any risk of harming the health of the worker, and management is easy.

FIG. 6 is a cross-sectional view showing another embodiment of the present invention.
This embodiment shows an example in which the minus lens 51 having a non-uniform edge thickness T is polished. The lens 50 before polishing is a lens having a constant edge thickness. Since the lens holder 2 itself is the same as that of the above-described embodiment, the same parts and portions are denoted by the same reference numerals, and description thereof is omitted.
It will be apparent that the same effect as that of the above-described embodiment can be obtained even with such a spectacle lens 51.

FIG. 7 is a cross-sectional view before polishing showing still another embodiment of the present invention, and FIG. 8 is a cross-sectional view after polishing.
This embodiment shows an example applied to the concave surface polishing of the minus lens 53 having a uniform edge thickness T after polishing. The lens 52 before polishing is a lens having a constant edge thickness. Since the lens holder 2 itself is substantially the same as the above-described embodiment, the same parts and portions are denoted by the same reference numerals, and description thereof is omitted.
It will be apparent that such a spectacle lens 53 can provide the same effects as those of the above-described embodiment.

It is sectional drawing of the state which blocked the positive lens which shows one Embodiment of the lens holder which concerns on this invention. It is sectional drawing which showed the state after grinding | polishing of the plus lens shown in FIG. It is sectional drawing of the state which blocked the minus lens which shows one Embodiment of the lens holder which concerns on this invention. It is sectional drawing which showed the state after grinding | polishing of the negative lens shown in FIG. It is a schematic block diagram of the grinding | polishing apparatus using the lens holder. It is sectional drawing which shows other embodiment of this invention. It is sectional drawing before grinding | polishing which shows other embodiment of this invention. It is sectional drawing after grinding | polishing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 ', 1 "... Eyeglass lens, 1a, 1d ... Concave surface, 1b ... Convex surface, 2 ... Lens holder, 3 ... Metal holding part, 3A ... Yato, 3B ... Alloy, 4 ... Low melting point wax, 4B ... Extension Part, 8 ... protective film, 19 ... polishing pad, 50-53 ... lens.

Claims (3)

  It comprises a metal holding part that blocks the central part of the convex surface of the optical lens before polishing, and a low melting point wax that blocks the outer peripheral part of the convex surface and has a melting point of 60 to 80 ° C. A lens holder comprising an annular extension portion that blocks an outer periphery and a part of a convex surface. The lens holder according to claim 1,
The low-melting wax has a radial length of the extension portion of 0.5 mm or more, and the surface of the extension portion has a height substantially equal to the outer peripheral edge height of the concave surface of the lens before polishing. A lens holder characterized by being polished to the same or approximate curved surface. Blocking the central part of the convex surface of the optical lens before polishing with a metal holding part,
Blocking the outer peripheral portion and the edge surface of the convex surface with a low melting point wax having a melting point of 60 to 80 ° C .;
Polishing the concave surface of the lens to a predetermined curved surface,
A method of polishing a curved surface of a lens, wherein the surface of a portion of the low melting point wax that extends outward from the edge surface is polished to a curved surface that is the same as or approximate to the peripheral edge of the concave surface when the concave surface is polished.

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