JP2009125877A - Lens holder and curved-surface polishing method for lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens holder for use in polishing an optical surface of a convex lens smaller in outside diameter than before polishing. <P>SOLUTION: A lens base material 1 has a convex lens shape with an edge thickness of almost zero. The lens holder 2 comprises a metal holding part 3 blocking a central portion of a convex surface 1b of the lens base material 1 and low-melting-point wax 4 blocking a peripheral portion of the convex surface 1b. The metal holding part 3 comprises a fixture 3A and an alloy 3B. An outside diameter Dy<SB>4</SB>of the alloy 3B is set to be smaller than the outside diameter of the convex lens manufactured by convex surface polishing of the lens base material 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens holder used for polishing an optical lens and a curved surface polishing method for a lens, and more specifically, a lens holder suitable for optical surface polishing of a plus lens having an outer diameter after polishing smaller than that before polishing. And a method for polishing a curved surface of a lens.

  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. It can be carried out. For example, polishing is performed using a general-purpose polishing apparatus (TORO-X2SL) manufactured by Satis Loh, which is 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 blocking the lens with the lens holder, a protective film for preventing damage 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 for 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.

  Therefore, as conventional techniques for solving such problems, for example, a lens holder and a polishing method disclosed in Patent Documents 2 to 5 are known.

  In the method described in Patent Document 2, in order to prevent a reduction in shape accuracy due to a so-called edge of the workpiece, the workpiece has a slope that is the same as or close to the tangent to the peripheral edge of the workpiece surface. An abrasive yato having an inclined surface shape is attached to the outer periphery of the workpiece, and both the lens and the abrasive yatoi are polished. As a yatoy, a glassy yato made of steel or the same quality as a lens is used.

  In the method described in Patent Document 3, a dummy (same as Yatoi in the present invention) is fitted into the outer periphery of a work composed of optical components such as a lens and a prism, as in Patent Document 2, and this dummy and the work A first polishing step for polishing the surface of the workpiece, and a second polishing step for polishing the outer peripheral edge portion of the workpiece in anticipation of burrs (processing steps) generated at the boundary between the dummy and the workpiece by the first polishing step And the second polishing step is performed in at least one of a pre-process and a post-process of the first polishing process. The dummy is formed of the same material as the workpiece or a material having the same workability.

  In the method described in Patent Document 4, similarly to Patent Documents 2 and 3, the outer periphery of the surface to be processed is filled with a deformable slip-off member (same as Yatoi in the present invention). A surface to be processed and a single curved surface are formed on the surface, and the single curved surface surrounded by the through surface is polished by a polishing jig. As the blank member, an ultraviolet curable resin or a low melting point alloy is used.

  In the method described in Patent Document 5, a low-melting-point alloy or a high-viscosity low-melting-point wax is used as a bonding agent for integrally bonding lens blanks to Yato.

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, since this Yatoi is formed in a ring shape so as to surround the outer periphery of the lens, there is almost no edge thickness, and in the case of a plus lens whose outer diameter is smaller than before processing when polished, It becomes impossible to block during processing.

  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 blank member. In addition, since the outer white member is formed in an annular shape and the outer periphery of the lens is blocked, the lens outer diameter after processing is smaller than that before processing as in the methods described in Patent Documents 2 and 3 above. It cannot be applied to a plus lens at all.

  In the method described in Patent Document 5, only a low-melting-point wax is used as a bonding agent between the lens and the yatoi, and the edge portion is not held with the wax, so that there is a problem that edge fringing occurs.

  As described above, the conventional techniques described in Patent Documents 2 to 5 are intended for polishing a negative lens in which the refractive power (dpt) of the convex surface is smaller than the refractive power of the concave surface. This lens cannot be applied as it is to a plus lens whose power is greater than the refractive power of the concave surface, especially a plus lens whose outer diameter is smaller than that before polishing, and is suitable for polishing such a plus lens. Development of a method for polishing a curved surface of a holder and a lens is demanded.

  The present invention has been made to meet the above-mentioned problems and demands of the prior art, and the object of the present invention is to improve the polishing performance for the outer periphery in the optical surface polishing of a plus lens whose diameter is reduced after polishing from the state before polishing. An object of the present invention is to provide a lens holder capable of improving efficiency, improving quality and shortening polishing time, and a method of polishing a curved surface of a lens using the same.

  In order to achieve the above object, the present invention is a lens holder used for optical surface polishing of a plus lens whose outer diameter after polishing is smaller than that before polishing, and is a polished surface of a lens substrate before polishing. A metal holding part that blocks a central part of the opposite surface and a low melting point wax having a melting point of 60 to 80 ° C. that blocks the outer peripheral part of the surface; The diameter is set smaller than the lens outer diameter after processing.

  Further, in the present invention, the present invention is such that the outer diameter of the portion to be joined to the surface of the metal holding portion is set to be smaller than the processed lens outer diameter by 0.5 mm or more.

  In the invention described above, the low melting point wax is integrally provided with an annular extension that blocks the outer periphery of the lens base material.

  In the present invention, the metal holding portion is configured by a yatoy made of a high melting point metal and a low melting point metal interposed between the yato and the lens base material.

  Furthermore, the present invention is a method of polishing a curved surface of a lens for polishing an optical surface of a plus lens whose outer diameter after polishing is smaller than that before polishing, and is a surface opposite to the surface to be polished of a lens substrate before polishing A step of blocking the central portion of the lens substrate with a metal holding portion, a step of blocking the outer peripheral portion of the surface with a low melting point wax having a melting point of 60 to 80 ° C., and the polished surface of the lens substrate together with the low melting point wax And polishing a predetermined curved surface to produce a plus lens having an outer diameter smaller than the outer diameter before polishing and larger than the outer diameter of the portion of the metal holding portion bonded to the lens base material. It is what.

  In the present invention, since the low melting point wax that blocks the outer peripheral portion of the surface opposite to the surface to be polished of the lens base material is provided, the lens can be blocked and processed even with a plus lens having almost no edge thickness. Easy. Further, when the lens outer diameter becomes small during polishing, the wax is polished to a curved surface whose outer side is the same as or close to the peripheral edge of the surface to be polished. Therefore, the outer periphery of the surface to be polished can be pressed and polished with the same pressure as the central portion, the polishing pad can be deformed uniformly and no edging occurs, and the shape of the surface to be polished The accuracy can be improved and the polishing time can be shortened.

  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. Also, the wax is easy to mold and can be processed with high accuracy.

  In the present invention, since the outer diameter of the portion to be joined to the lens base of the metal holding part is set to be 0.5 mm or more smaller than the lens outer diameter after processing, only the lens base and the low melting point wax are set. Can be polished, and the influence on the polishing pad can be reduced. That is, when the polishing pad polishes the metal holding portion, the wear of the pad is accelerated, and the processing resistance is different between the lens base, the wax, and the metal holding portion, so that the pad is deformed and the applied pressure becomes uneven. However, since the metal holding portion is not polished in the present invention, such a problem does not occur.

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 lens substrate before processing is blocked by a lens holder according to the present invention, and FIG. 2 is a cross-sectional view after polishing. In these drawings, 1 is a lens base material that is a lens to be processed, 2 is a lens holder for holding the lens base material 1, 10 is a plus lens after polishing, and 11 is a surface to be polished of the lens base material 1. This is a polishing pad for producing a plus lens 10 having a concave surface 10a (FIG. 2) made of an optical surface having a predetermined curvature by polishing the concave surface 1a.

The lens substrate 1 is not particularly specified, and is made of a plastic semi-finished lens having a high refractive index (n = 1.55 to 1.75) formed of, for example, a urethane or epithio resin, and is polished. The surface 1a is a concave surface, and the surface 1b opposite to the surface to be polished 1a forms an optical surface composed of a convex surface having a predetermined curvature. The lens base 1 is a circular lens (including an ellipse) having an outer diameter Dy ₁ of, for example, 65 mmφ and an edge thickness T almost zero in the state before processing shown in FIG. By setting the refractive power D ₁ (dpt) to be larger than the refractive power D _{2 of the} convex surface 1b (D ₁ > D ₂ ), a positive lens substrate is formed. Plus lens 10 after polishing is the edge thickness is zero, the refractive power D ₃ of the concave 10a is larger than the refractive power D ₂ of the convex surface 10b, the outer diameter Dy ₁ smaller outer diameter Dy of the lens substrate 1 before polishing Have _two .

The lens holder 2 is composed of two members, a metal holder 3 and a wax 4. Further, the metal holding part 3 is interposed between a Yato 3A made of a high melting point metal such as SUS303 and the Yato 3A and the convex surface 1b of the lens base 1 to join the lens base 1 and the Yato 3A ( (Low melting point alloy) 3B. Lens holder unit 3A is formed in the outer diameter Dy ₃ example 43mmφ cylindrical, is is prevented to rotate in the fitting recess 38a and the portion which is fitted detachably in the rotary shaft 38 of the polishing apparatus 30 described later. The reason for using the Yatoi 3A made of a high melting point metal and having high mechanical strength as the metal holding part 3 that blocks the central part of the convex surface 1b of the lens substrate 1 is to prevent deformation due to a load during polishing. is there.

As the alloy 3B, a known alloy such as a mixture of tin, indium, bismuth, and the like can be used. The alloy 3B is formed in a disc shape having an outer diameter Dy ₄ (for example, 50 mmφ) that is smaller than the outer diameter Dy ₁ of the lens base material 1 and larger than the outer diameter Dy ₃ of the yato 3A, and is formed on the convex surface 1b of the lens base material 1. The contacting surface forms the lens holding surface 6 and is bonded to the center of the convex surface 1 b of the lens base 1. For this reason, the lens holding surface 6 forms a concave surface having the same radius of curvature as the convex surface 1b. The outer diameter Dy ₄ of the alloy 3B is set slightly smaller than the outer diameter Dy ₂ of the polished plus lens 10 so as not to be polished by the polishing pad 11 when the concave surface 1a is polished. The outer diameter difference Dy ₄ -Dy ₂ is preferably about 0.5 mm or more, and if it is more than this, the surface of the alloy 3B is not polished. In the center of the lower surface of the alloy 3B, the upper end of the yatoy 3A is embedded. For this reason, the central part of the alloy 3B forms a thin part having a thickness of about 2 mm. In forming such an alloy 3B, as will be described later, the alloy material is heated and melted and poured into the gap between the lens substrate 1 and the yatoy 3B to be solidified.

The wax 4 is made of a low melting point wax, and is formed in an annular body surrounding the outer periphery of the alloy 3B, so that the convex surface 1b of the lens substrate 1 extends from the outer periphery of the alloy 3B to the outer periphery of the lens substrate 1. The convex outer part is blocked. For this reason, the outer diameter of the wax 4 is equal to the outer diameter Dy ₁ of the lens substrate 1 before polishing, and the inner diameter is equal to the outer diameter Dy ₄ of the alloy 3B.

  As the wax 4, there is no particular limitation on the material, and a very general 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, a manufacturing procedure of the plus lens 10 will be described.
FIGS. 3A to 3F are cross-sectional views for explaining the holding and polishing steps of the lens substrate 1 by the lens holder 2.
First, the lens base material 1 whose concave surface 1a is not processed is prepared (FIG. 3A). Next, the protective film 8 is stuck on the convex surface 1b of the lens substrate 1 (FIG. 3B).

  The protective film 8 is used for preventing the convex surface 1b of the lens substrate 1 from being scratched and for facilitating the removal of the lens holder 2 after polishing. For example, a surface layer, an intermediate layer, The adhesive layer is composed of a three-layer structure. 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 10 μm for the surface layer, 85 μm for the intermediate layer, and about 25 μm for the adhesive layer. . The protective film 8 may have a two-layer structure of a base material layer such as polyethylene made of a film-like solid at normal temperature and an adhesive layer made of polyolefin. Its physical properties are a film-like solid at room temperature, a melting point of 110 to 130 ° C., and a specific gravity of 0.9 to 1.0. Conventionally, the protective film 8 is used to protect the lens base material 1 and ensure close contact with the alloy 3B. However, in the case of extrapolated wax, the close contact with the lens base material 1 can be sufficiently secured. In the present invention, the lens substrate 1 is mainly used for preventing scratches.

  Next, the outer peripheral portion of the convex surface 1b of the lens substrate 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. 3C). When the molten alloy 3B is poured into the space 15 and solidified (FIG. 3D). The lens substrate 1 is bonded to the Yatoi 3A via the alloy 3B. In other words, the lens substrate 1 is blocked by the metal holding part 3.

  Next, after the alloy 3B is solidified, the blocking ring 14 is removed, and the lens base 1 in which the Yatoi 3A is bonded to the wax blocking ring 16 having a larger outer diameter via the alloy 3B is mounted. Further, the wax 4 melted in the space 17 formed by the outer periphery of the lens substrate 1, the outer periphery of the alloy 3 </ b> B, and the inner periphery of the blocking ring 16 is filled to the outer periphery height of the lens substrate 1 and solidified. The lens substrate 1 is blocked (fixed) (FIG. 3E).

  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 into the blocking ring 16. At this time, it is preferable to provide an air vent hole or gap (both not shown) in a part of the periphery of the blocking ring 16.

  The melting point of the wax 4 can be used without any 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. Further, although the hardness of the wax 4 is not particularly specified, a softer one than the lens base material 1 is selected in order to reduce damage to the polishing pad 11 due to the edge of the lens base material 1 and to suppress the wear of the pad itself as much as possible. It is preferable to do.

  The primary effect of the extrapolated wax is to move the unpolished portion of the workpiece (pointing to a portion of 3 to 4 mm from the outer circumference) to the extrapolated portion of the workpiece. Furthermore, as a method of improving the polishing of the outer peripheral portion, a known abrasive such as alumina, silica, zirconia, ceria, manganese oxide, diamond can be added to the extrapolated wax, and in the case of a plastic lens, alumina is used. It is preferable to carry out. When the lens base material 1 is blocked by the lens holder 2, for example, the lens base material 1 is blocked by using an apparatus called a layout blocker manufactured by Saty Law. 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 substrate 1 is mounted on a polishing apparatus, and the concave surface 1b is polished to a predetermined curved surface by the polishing pad 11 (FIG. 3 (f)).

Next, the polishing apparatus 30 used for polishing the spectacle lens substrate 1 will be described.
In FIG. 4, a polishing apparatus 30 is used for polishing the concave surface 1a of the lens substrate 1 (see, for example, Japanese Patent Application Laid-Open No. 2003-266287), and an apparatus main body 31 installed on the floor surface and The apparatus main body 31 is movable in the left-right direction on the paper surface and is pivoted in a direction orthogonal to the paper surface around a horizontal shaft 32, and the arm 33 is reciprocated in the left-right direction. In addition, a driving device (not shown) that rotates in a direction orthogonal to the paper surface, a lens mounting portion 34 that is provided on the arm 33 and blocks the convex surface 1b of the lens base 1 through the lens holder 2, and the lens mounting A swing which is disposed in the apparatus main body 31 so as to be positioned below the portion 34 and swings around the vertical axis K (does not rotate) by a driving device (not shown). It is equipped with a device 35 and the like. Further, a polishing jig 36 detachably provided on the swing device 35, the polishing pad 11 detachably attached to the polishing jig 36, and a lens attachment portion 34 installed on the arm 33 are provided. An elevating device 37 for elevating and lowering is provided.

  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 the surface portion 39A contacting the concave surface 1a of the lens substrate 1 is a flat or gently convex curved surface, and is compressed air introduced into the interior during use. Thus, the lens base 1 is 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). Note that it is preferable to prepare a plurality of types of balloon members 39 according to the size of the lens substrate 1 to be polished and the shape of the surface to be polished.

  The polishing pad 11 used for polishing the concave surface 1a of the lens substrate 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 shape of the dome portion 39A. For example, eight fixing pieces 11a are extended on the periphery, and these fixing pieces 11a are The balloon member 39 is detachably fixed by a fastening member 40 which is bent along the outer periphery of the balloon member 39 and is formed of a wire spring having an appropriate thickness.

  In order to attach the polishing pad 11 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 11 is placed thereon. Next, the fixing piece 11a 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 11a.

  The lens substrate 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 substrate 1 is attached to the lens mounting portion 34 of the arm 33. Next, a polishing jig 36 that blocks the polishing pad 11 is installed on the upper surface of the swinging device 35, and the lens substrate 1 is lowered by the lifting device 37 to press the concave surface 1 a against the surface of the polishing pad 11. In this state, the abrasive is supplied to the surface of the polishing pad 11 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 substrate 1 is polished by the polishing pad 11 and the abrasive with a trackless polishing locus in which the polishing locus is slightly shifted every round, and finished to an optical surface having a desired curved surface.

  When the manufacture of the plus lens 10 is completed by polishing the lens substrate 1, the lens holder 2 is removed from the polishing apparatus 30 together with the plus lens 10, and the plus lens 10 is further removed from the lens holder 2. Then, the visual inspection of the plus lens 10 by visual inspection, the power inspection by the lens meter, the projection inspection of the lens inner surface by the transmitted light of the zircon lamp and the optical performance inspection of astigmatism are performed, and the manufacture of the plus lens 10 is finished.

As described above, the lens holder 2 according to the present invention is a plus lens 10 having almost no edge thickness because the outer peripheral portion of the convex surface 1b of the lens substrate 1 before polishing is held by the low melting point wax 4. However, when the outer peripheral portion of the concave surface 1a is polished, the same pressing force as that of the central portion of the concave surface can be applied for polishing. Further, the outer side of the plus lens 10 on the upper surface of the wax 4 is also polished at the same time when the concave surface 1a is polished, and is polished to a curved surface that is the same as or close to the peripheral edge of the concave surface 10a. Accordingly, the plus lens 10 whose lens outer diameter Dy ₂ after polishing is smaller than the lens outer diameter Dy ₁ before polishing can be satisfactorily polished without being edged, and the peripheral portion is not edged. The processing time can be greatly shortened because the time and effort of machining is saved.

  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 substrate 1, can be easily solidified by cooling, can be molded in a short time (about 15 minutes at room temperature), and can be processed with high accuracy. Can be easily removed from the plus lens 10 by heating for about 15 minutes. Further, after the removal, the wax 4 is diluted with a solvent together with the chips, heated and dissolved, and then removed by removing the volatile component, so that the consumption of the wax 4 can be reduced 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. 5 is a sectional view before processing showing another embodiment of the present invention, and FIG. 6 is a sectional view after processing.
In this embodiment, an annular portion 4 </ b> A surrounding the edge surface 1 c of the lens substrate 1 over the entire circumference is integrally extended on the outer periphery of the low melting point wax 4. Other configurations are completely the same as those of the embodiment shown in FIGS. 1 and 2, and therefore, the same parts and portions are denoted by the same reference numerals and the description thereof is omitted.

The convex surface 1b of the lens substrate 1 is blocked by such a lens holder 2 ′ to polish the concave surface 1a, and as shown in FIG. 6, the plus lens 10 having an outer diameter Dy ₂ smaller than the outer diameter Dy ₁ before polishing is obtained. To manufacture. Therefore, the outer side of the outer periphery of the plus lens 10 on the upper surface of the wax 4 is also polished to a curved surface that is the same as or close to the peripheral edge of the concave surface 10a, and the same effect as the above-described embodiment can be obtained. Will be clear.

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 is applied to the case where the plus lens 51 is manufactured by polishing one surface 50a of the lens substrate 50 having a flat surface in which both surfaces 50a and 50b are substantially parallel to each other to an optical surface 51a having a predetermined convex curved surface. An example is shown.

The lens base 50 is blocked by the lens holder 2 on the surface 50b opposite to the surface (surface to be polished) 50a to be polished. Similarly to the embodiment shown in FIGS. 1 and 2, the lens holder 2 includes a metal yatoy 3A and a surface 50b opposite to the surface to be polished 50a of the lens base material 50. It is composed of an alloy 3B interposed therebetween and a low melting point wax 4 that blocks the outer periphery of the surface 50b. The outer diameter Dy ₄ of the alloy 3B is set smaller than the outer diameter Dy ₂ of the polished plus lens 51.

When the polished surface 50a of the lens substrate 50 is polished to produce a plus lens 51 having a predetermined convex surface 51a, the outer periphery of the wax 4 is reduced by polishing the outer periphery of the polished surface 50a with a polishing pad. Is also polished at the same time, the outer peripheral surface of the wax 4, that is, the surface portion outside the lens outer diameter Dy ₂ of the plus lens 51 is polished to a curved surface that is the same as or close to the peripheral edge of the convex surface 51 a after processing. Is done. Therefore, it will be apparent that the same effect as that of the above-described embodiment can be obtained even when the plus lens 51 having a substantially zero edge thickness is manufactured from the flat lens substrate 50.

It is sectional drawing which shows the state which blocked the lens base material before a process with the lens holder which concerns on this invention. It is sectional drawing after grinding | polishing process. (A)-(f) is sectional drawing for demonstrating the holding | maintenance and grinding | polishing process of a lens base material with a lens holder. It is a schematic block diagram of a grinding | polishing apparatus. It is sectional drawing before the process which shows other embodiment of this invention. It is sectional drawing after a process. It is sectional drawing before the process which shows other embodiment of this invention. It is sectional drawing after a process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lens base material, 1a ... Concave surface (surface to be polished), 1b ... Convex surface, 1c ... Edge surface, 2 ... Lens holder, 3 ... Metal holding part, 3A ... Yato, 3B ... Alloy, 4 ... Low melting point wax, 4A ... Extension part, 8 ... Protective film, 10 ... Plus lens, 11 ... Polishing pad.

Claims (5)

A lens holder used for optical surface polishing of a plus lens whose outer diameter after polishing is smaller than that before polishing,
A metal holding part that blocks the central part of the surface opposite to the surface to be polished of the lens base before polishing, and a low melting point wax having a melting point of 60 to 80 ° C. that blocks the outer peripheral part of the surface,
A lens holder, wherein an outer diameter of a portion joined to the surface of the metal holder is set to be smaller than a lens outer diameter after processing. The lens holder according to claim 1,
The lens holder according to claim 1, wherein an outer diameter of a portion of the metal holder that is joined to the surface is set to be 0.5 mm or more smaller than a lens outer diameter after processing. The lens holder according to claim 1 or 2,
The lens holder according to claim 1, wherein the low melting point wax is integrally provided with an annular extension that blocks an outer periphery of the lens substrate. The lens holder according to any one of claims 1, 2, and 3,
The metal holder is constituted by a yatoy made of a high melting point metal and a low melting point metal interposed between the yato and the lens base material. A lens curved surface polishing method for polishing an optical surface of a plus lens whose outer diameter after polishing is smaller than that before polishing,
A step of blocking the central portion of the surface opposite to the surface to be polished of the lens substrate before polishing with a metal holding portion;
Blocking the outer periphery of the surface with a low melting point wax having a melting point of 60 to 80 ° C .;
By polishing the surface to be polished of the lens substrate into a predetermined curved surface together with the low melting point wax, the outer diameter is smaller than the outer diameter of the lens substrate before polishing, and the lens substrate of the metal holding portion Manufacturing a plus lens larger than the outer diameter of the joined part;
A curved surface polishing method for a lens, comprising:

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