JP2012213821A - Method for manufacturing spectacle lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for adjusting prism operation without impairing the exterior appearance of a spectacle lens.SOLUTION: A method for manufacturing a spectacle lens includes steps for: cutting off part of at least one surface of a spectacle lens by mechanical machining and subjecting the spectacle lens to slab-off processing for adjusting the prism operation; and then polishing a surface of the cut-off region where the polishing processing is performed while covering a surface of a polishing tool formed of an elastic material with a polishing pad by moving the spectacle lens and a polishing tool relatively to each other while feeding a polishing agent between a surface of the polishing pad and the surface of the cut-off region.

Description

  The present invention relates to a method for manufacturing a spectacle lens, and more particularly to a method for manufacturing a spectacle lens in which the prism action is adjusted to improve the feeling of wearing.

  The multifocal spectacle lens includes a distance portion having a distance power for far vision and a near portion having a near power for near vision. In addition, in a multifocal spectacle lens, a progressive power lens having a progressive surface whose refractive power continuously changes from the upper part toward the lower part has a refractive power continuously between the distance portion and the near portion. It has an intermediate part that changes.

Generally, in spectacle lens prescriptions, in addition to the above-mentioned refractive power related to the focal effect such as the distance power and the near power, there is a prism power that changes the direction of the line of sight. To do. When manufacturing a multifocal spectacle lens, when determining the refractive power of the distance portion, the refractive power of the near portion is determined by the shape of the progressive surface, the distance portion's refractive power and the addition power, and for the same reason. If the prism refractive power of the near portion is determined, the prism refractive power of the distance portion is determined. Accordingly, it is difficult to freely select the refractive powers of the distance portion and the near portion.
However, most spectacle wearers do not have the same visual acuity. Accordingly, if the prism amounts of the left and right lenses are matched in one of the distance portion and the near portion, a difference occurs in the prism amounts of the left and right lenses on the other side. This is called prism error, and there is a large difference in power between the left and right, so the glasses error for so-called non-sighted wearers causes the prism error to become extremely large, causing eyestrain and headaches. If the deviation of the light incident on the human exceeds the limit that the human brain can image, a double image is formed, causing the symptom of double vision.

  Conventionally, slab-off processing is known as means for suppressing the occurrence of the above phenomenon. The slab-off process is a process of cutting a part of the lens surface in order to adjust the prism action of the lens, and the amount of prism can be reduced by cutting. In a spectacle lens subjected to such a slab-off process, as described in Patent Document 1, a boundary line between the ablated region subjected to the slab-off process and an uncut region (hereinafter referred to as “slab offline”). ) Is visually confirmed.

WO2009 / 072528

  As described above, the slab-off process is an effective means for improving the feeling of wearing, particularly in a spectacle lens used for a user who is not sighted. However, since the slab offline appears clearly after the slab-off processing, the appearance of the progressive-power lens having the advantage that the boundary between the distance portion and the near portion is inconspicuous is greatly impaired. In addition, in the multifocal lens, the appearance is impaired due to the occurrence of the slab offline in addition to the boundary line between the distance portion and the near portion.

  Accordingly, an object of the present invention is to provide means for adjusting the prism action without impairing the appearance of the spectacle lens.

As a result of intensive studies to achieve the above object, the present inventors have obtained the following new knowledge.
As a polishing process in the manufacturing process of a spectacle lens, a sliding polishing using a metal polishing dish having a surface shape coinciding with a surface to be polished is widely performed. The sliding polishing using a metal polishing dish has an advantage that an optical surface can be easily obtained without impairing the surface shape formed by machining such as cutting because the shape accuracy is good. However, in the slab-off process in which the prism action is adjusted by cutting off part of the lens surface and leaving other areas uncut, there is a difference in level (step) between the cut and uncut areas. The processed surface is not a smooth surface. Since it is practically impossible to prepare a surface-shaped metal polishing plate that matches this processed surface, the polishing process after the conventional slab-off processing is performed using a surface-shaped metal polishing plate different from the surface to be polished. It was done using a dish. The inventors of the present invention have considered that the occurrence of unpolished at the boundary between the ablated region and the unexcised region in such a polishing process is the reason that the slab offline is clearly visible in the slab-off processed lens. It was.
As a result of further studies based on such knowledge, the present inventors have newly found that the visibility of the slab offline can be reduced by polishing using a polishing jig made of an elastic member after slab-off processing. I found it. The present inventors speculate that this is due to the fact that the elastic member is deformed and can be satisfactorily matched to the surface to be polished, so that the occurrence of unpolished residues at the boundary portion can be suppressed.
The present invention has been completed based on the above findings.

That is, the above object was achieved by the following means.
[1] including performing a slab-off process in which a part of at least one surface of the spectacle lens is cut by machining to adjust the prism action, and then polishing the surface of the cut region;
In the state where the polishing jig surface made of an elastic material is covered with a polishing pad, the polishing process is performed while supplying an abrasive between the polishing pad surface and the ablation region surface, and the spectacle lens and the polishing jig A method for manufacturing a spectacle lens, wherein the eyeglass lens is moved relative to each other.
[2] A dome-shaped surface is formed by supplying a fluid to the inside of the polishing jig and expanding it.
The method for manufacturing a spectacle lens according to [1], wherein the polishing process is performed by covering the dome-shaped surface with the polishing pad.
[3] The spectacle lens according to [1] or [2], including a period during which the polishing jig is swung in a direction substantially orthogonal to a boundary between the cut region and the uncut region during the polishing process. Production method.
[4] The spectacle lens according to any one of [1] to [3], wherein the slab-off processing is performed in a state where an area to be excised is uncoated and an area to be excised is covered with a coating on the surface. Manufacturing method.

  According to the present invention, it is possible to provide a spectacle lens having a good appearance and wearing feeling.

It is explanatory drawing of the one aspect | mode of a slab-off process. It is explanatory drawing of a slab-off process area | region. The specific example of the cross-sectional shape of a plastic bifocal lens is shown. It is a figure which shows the position of the optical center of the near part of the bifocal lens shown to Fig.3 (a)-(c). It is a schematic block diagram of the polisher which can be used in this invention. It is sectional drawing which shows the state which attached the lens of grinding | polishing object to the lens holding body. It is explanatory drawing of the swing rotation motion of a rocking | fluctuation apparatus and a grinding | polishing jig | tool. It is a top view which shows an example of a grinding | polishing jig | tool. It is a top view which shows the state which attached the polishing pad to the polishing jig | tool shown in FIG. It is a bottom view which shows an example of a grinding | polishing jig | tool. It is the XII-XII sectional view taken on the line of FIG. It is a top view of a polishing pad. It is a figure which shows an example of the movement locus | trajectory of the lens of grinding | polishing object.

The present invention relates to a method for manufacturing a spectacle lens, which includes performing a slab-off process of adjusting a prism action by cutting a part of at least one surface of a spectacle lens and then polishing the surface of the cut region. The spectacle lens manufacturing method of the present invention provides the polishing process by supplying an abrasive between the polishing pad surface and the ablation region surface in a state where the polishing jig surface made of an elastic material is covered with the polishing pad. However, this is performed by relatively moving the spectacle lens and the polishing jig. Thereby, since the visibility of a slab offline can be reduced, it is possible to improve the wearing feeling by slab-off processing without impairing the appearance of the spectacle lens.
Hereinafter, the manufacturing method of the spectacle lens of this invention is demonstrated in detail with reference to drawings.

  FIG. 1 is an explanatory diagram of a process of performing slab-off processing on the optical surface of a bifocal lens (semi-finished lens). The processed lens shown in FIG. 1A is a bifocal lens in which a small lens is embedded in a pedestal lens, and a near portion is formed by the small lens. In the bifocal lens having such a configuration, in the case of near vision, a region about 8 to 10 mm below the optical center of the ball lens is used, and a prism is generated in the near portion due to the strength of the lens power. . If the power difference between the left and right lenses is 1.00D or less, the prism is also within 1Δ, and the wearing feeling is not impaired when viewing with both eyes, but if the difference is 1.5D or more, the left and right imbalance due to the prism is significant. It becomes. In this case, by removing at least a part of the left or right lens (slab-off processing), the prism action of the left and right lenses can be adjusted to improve the wearing feeling during binocular vision. Specifically, as shown in FIG. 1B, a dummy lens having a surface shape obtained by transferring the shape of the processing surface is bonded to the processing surface. Next, as shown in FIG. 1C, the region to be cut out (slab-off processing region) is removed together with the dummy lens by machining.

  The machining can be performed by grinding, cutting, or the like. In general slab-off processing, a region to be cut is ground or ground by a curve generator. However, since the machined surface is rough and cannot usually be used as an optical surface as it is, polishing is performed after the slab-off processing to create an optical surface on the slab-off-processed surface. Details of the polishing step will be described later.

  FIG. 1 shows an example of processing a semi-finished lens, but machining (grinding or cutting, and subsequent polishing) for creating an optical surface on the non-optical surface (concave surface in FIG. 1) of the semi-finished lens. Is usually performed before removing the dummy lens remaining after the slab-off processing. The lens in which the optical surface is thus created is in the state shown in FIG. 1D, and a spectacle lens (FIG. 1E) subjected to slab-off processing is obtained by removing the dummy lens from the lens in this state. As shown in FIG. 1E, the lens surface from which the dummy lens is removed has a boundary (slab offline) between the uncut region and the cut region protected by the dummy lens.

  In FIG. 1, the embodiment in which the slab-off process is performed on the semi-finished lens has been described. It may be a semi-finished lens that is an optical surface and the other surface is a non-optical surface, and an optical surface having desired optical characteristics is created according to the user's needs after receiving an order. Moreover, the shape of the surface on which the slab-off process is performed can be any shape such as a flat surface, a convex surface, or a concave surface. The material of the spectacle lens subjected to the slab-off process is not particularly limited, and various materials used as a normal spectacle lens material such as plastic and inorganic glass can be exemplified.

In the embodiment described with reference to FIG. 1, for example, when the work surface is a convex surface as shown in FIG. 1, a dummy lens having a concave surface with the convex shape transferred is produced, and the concave surface of this dummy lens is produced. Is fitted to the work surface (convex surface). If the surface to be processed is a spherical surface, it is easy to form a surface shape obtained by transferring the surface (that is, a spherical surface) on the dummy lens.
On the other hand, the progressive power lens described above is a lens having a distance portion and a near portion, and having a progressive surface whose refractive power gradually changes from the distance portion to the near portion. The progressive power lens includes a convex (outer surface) progressive power lens in which a progressive surface is disposed on a convex surface and a concave (inner surface) progressive power lens in which a progressive surface is disposed on a concave surface. The convex progressive-power lens has a progressive surface on the convex surface, and forms a progressive refractive power by the surface shape of the optical surface of the convex surface. The concave refractive power lens is the same except for the difference in the unevenness. It is difficult to produce a dummy lens having a surface shape obtained by transferring the optical surface of a spectacle lens having a complicated shape with an in-plane curvature different from that of the progressive-power lens. Even if it is necessary to prepare dummy lenses corresponding to various surface shapes according to the lens prescription, this causes an increase in manufacturing cost. Among the bifocal lenses, the plastic bifocal lens has a near portion and a far portion by projecting small balls on the convex surface side (object side), and therefore corresponds to the surface shape on the convex surface side. It is difficult to make a dummy lens.

In the present invention, when a slab-off process is performed on a lens surface having a complicated surface shape as described above, the region to be cut should be uncovered and uncut on the surface to be processed regardless of the dummy lens. Slab-off processing is preferably performed in a state where the region is covered with a coating. As will be described later, since the coating film can be formed of a photo-curing resin, a masking tape, or the like, it is easy to correspond to the surface of a complicated surface shape. Therefore, according to this aspect, slab-off processing can be easily performed on a free-form surface including a progressive element. Also, slab-off processing can be easily performed by forming a film on the convex surface of the bifocal lens having the protruding portion. Thus, according to this aspect, the prism action can be adjusted by performing the slab-off process on the lens surfaces having various surface shapes.
Below, the slab-off process using the said film is demonstrated with reference to drawings.

  2 is a cross-sectional view of a progressive-power lens having a convex surface on the object side and a concave surface on the eyeball side, and a near portion is disposed below the optical center. The right side of FIG. 2 is a plan view of the concave surface. In this concave surface, a region above the near portion (region above the solid line) is cut off by a predetermined amount by machining to reduce the longitudinal prism difference in distance vision. In this case, since the hatched portion in the right diagram of FIG. 2 is a region to be an uncut region, the region is covered with a film. The film may be formed by depositing an inorganic material or a metal material by a known film forming method such as vapor deposition or sputtering, or for forming a film by a known coating method such as a dip method, a spin coating method, or a spray coating method. You may form by apply | coating a coating liquid. For example, a film can be formed in a desired area by performing a film forming process on the entire surface of the lens in a state where an area to be uncoated is protected with a masking tape, and removing the masking tape after the process. From the viewpoint of ease of film formation, a coating method is preferably used. As the coating solution, a composition containing a thermosetting component or a photocurable component (curable composition) can be used, and a desired curing treatment (heating or light irradiation) is performed on the lens surface after coating. A cured film can be formed at the position. It is preferable to use a photocurable composition such as an ultraviolet curable composition because it can be cured in a short time. Such a curable composition can be prepared by a well-known method, and what is generally marketed as a hard coat coating material for spectacle lenses can be used without any limitation. Alternatively, a masking tape can be used as the coating. As the masking tape, a commercially available protective tape having an adhesive layer or an adhesive layer on one or both sides of the support film can be used. The thickness of the coating is not particularly limited and can be, for example, about 10 to 50 μm. The thickness of the coating can be controlled by the film forming conditions and the coating conditions. Moreover, in the aspect using said masking tape, you may laminate | stack several masking tapes as needed so that total thickness may become desired thickness.

On the other hand, a plastic bifocal lens usually has a distance portion and a near portion by providing a protrusion (near portion) on a part of at least one surface as described above. A specific example of the cross-sectional shape of such a bifocal lens is shown in FIG. FIG. 3A shows a positive refractive power for the distance portion and the near portion, FIG. 3B shows a negative refractive power for the distance portion, a positive refractive power for the near portion, and FIG. Both the distance portion and the near portion are negative refractive power lenses. In FIG. 3, A is the optical center of the distance portion, B is the geometric center of the near portion, and the optical centers of the near portion in each case are as shown in FIGS. 4 (a) to 4 (c), respectively. , Move between A and B according to the refractive power difference (additional power) between the distance portion and the near portion at positions below B and above A.
When a slab-off process is performed on the convex surface having a protruding portion in part in the manner described based on FIG. 1, a concave portion that fits the protruding portion is formed on the concave surface of the dummy lens. It is difficult to produce a dummy lens having such a surface shape. In this case, for example, in the bifocal lens having the cross-sectional shape shown in FIGS. 3A to 3C, the lower region including the convex protrusions (the region below the dotted line in FIGS. 4A to 4C). The prism action can be adjusted in the region above the projecting portion of the convex surface by performing the slab-off process in a state where it is covered with a coating and the region above the projecting portion is uncovered.

  In the slab-off process, the jig used for machining may contact the coating. Since it is protected by the coating, the region under the coating becomes an uncut region.

  Next, after the adjustment of the prism action by the slab-off process described above, the polishing process performed on the slab-off-processed surface will be described.

  In the present invention, the polishing applied to the slab-off processed surface is performed by supplying a polishing agent between the polishing pad surface and the ablation region surface in a state where the polishing jig surface made of an elastic material is covered with the polishing pad. However, it is performed by relatively moving the spectacle lens and the polishing jig. Thereby, the visibility of a slab offline can be reduced. As described above, this is considered to be due to the fact that the unpolished portion of the boundary between the region cut by the slab-off process and the uncut region can be reduced by the deformation of the elastic member. The spectacle lens in which the slab offline is not easily visually recognized has a good appearance, and the wearer himself can use the spectacle lens without being aware of the slab offline.

  As a polishing jig made of an elastic material, a polishing body made entirely of an elastic material can be used, or a balloon member having a cavity (hollow structure) inside, and a balloon is supplied by supplying a fluid to the cavity. It is also possible to use a polishing body that can perform polishing while applying tension to the member. Since the latter polishing body can control the polishing conditions also by the pressure applied by the fluid, it is advantageous for further reducing the unpolished portion at the boundary between the ablated region and the unexcised region.

  The elastic material preferably has a property as an elastic body and has a hardness of about 5 to 70 as defined by JIS k 6253 (durometer type A or type E). Specific examples include natural rubber, synthetic rubber such as styrene butadiene rubber (SBR) and silicon rubber. The balloon member preferably has an elastic material portion with a thickness of about 1 to 10 mm. As the fluid supplied to the balloon member, liquids such as compressed air, nitrogen and water are usually used. Regarding the specific configuration of the polishing jig including the balloon member, reference can be made to, for example, paragraphs [0033] to [0037] of Japanese Patent Application Laid-Open No. 2004-261554, paragraphs [0036] to [0057] of Japanese Patent Application Laid-Open No. 2008-283714, and the like. .

  The polishing pad disposed on the surface of the polishing jig at the time of polishing serves to hold an abrasive and increase the polishing efficiency. Although it does not specifically limit as a polishing pad, For example, what uses fibrous cloth, synthetic resins, etc., such as foaming polyurethane, felt, a nonwoven fabric, and wool, can be used. The thickness is usually about 0.5 to 3.0 mm. Regarding the shape and arrangement method of the polishing pad, for example, paragraphs [0034] of JP-A No. 2004-261154, paragraphs [0026] to [0027] and [0058] to [0061] of JP-A-2008-183714 can be referred to. .

  As the polishing agent supplied between the polishing pad surface and the surface to be polished, a commercially available slurry that is usually used for polishing treatment can be used. Alternatively, a slurry prepared by dispersing abrasive grains such as alumina and diamond powder in water or an aqueous solvent can be used.

  Since the polishing process is a process for eliminating the roughness due to the machining of the excision area subjected to the slab-off process, it is performed at least on the excision area. However, the polishing jig may be in contact with a portion other than the excision region. The operation of the polishing jig during polishing and the operation of the spectacle lens that is the object of polishing can be the same as in the normal polishing process. Preferably, in a state where the polishing jig is pressed against the surface to be polished, the polishing jig is swung and swung and the spectacle lens is reciprocated so that the polishing path is slightly shifted every round. Polish the surface to be polished. Further, during polishing, the polishing jig can be moved in a direction substantially perpendicular to the boundary between the cut region and the uncut region, thereby further reducing the unpolished portion of the boundary portion. There is a remaining dummy lens or film on the surface of the lens on which the slab-off process has been performed according to the above-described embodiment. A portion covered with the dummy lens or the coating is an uncut region, and an uncovered portion is a cut region. The dummy lens and the film may or may not be removed before the polishing process. It is also possible to polish the entire surface after removing the film or dummy lens after polishing with the film or dummy lens attached. Since the presence of the dummy lens or coating serves as a mark of the boundary between the excised area and the unexcised area, it should be removed if a period for moving the polishing jig in a direction substantially perpendicular to the boundary between the two areas is provided. It is preferable to carry out the polishing process without using. The swing movement is preferably performed by reciprocating the polishing jig a plurality of times in a direction substantially orthogonal to the boundary. When the boundary line between the cut region and the uncut region is not a straight line, an approximate straight line is assumed, and the polishing jig may be swung in a direction substantially orthogonal to the approximate straight line. Note that the term “substantially orthogonal” is used to include a case where the direction is approximately ± 10 ° different from the orthogonal direction.

Next, an example of a specific embodiment of the polishing process will be described with reference to the drawings.
FIG. 5 is a schematic configuration diagram of a polishing apparatus that can be used in the present invention.
In the figure, a polishing apparatus generally indicated by reference numeral 30 has an apparatus main body 32 installed on the floor, and a horizontal axis 33 that can move in the left-right direction (arrow X direction) on the apparatus main body 32 in the drawing. An arm 34 rotatably disposed in a direction orthogonal to the paper surface (arrow AB direction), and a drive device (not shown) that reciprocates the arm 34 in the left-right direction and rotates in a direction orthogonal to the paper surface, The eyeglass lens (hereinafter also simply referred to as “lens”) 1 provided on the arm 34 is held by a lens mounting portion 36 via a block jig 37, and the lens mounting portion 36 is positioned below the lens mounting portion 36. The apparatus main body 32 is provided with a swinging device 38 and the like that swings and swings around the vertical axis K (does not rotate) by a driving device (not shown).

FIG. 6 is a cross-sectional view showing a state where the lens is attached to the lens holder 37.
In the figure, a lens holder 37 that holds the lens 1 is composed of a metal (tool steel, etc.) yatoi 44 and an adhesive 45 that joins the yatoi 44 and the lens 1. A fitting recess 47 that fits into the lens mounting portion 36 is formed on the back side of the yatoi 44. The fitting recess 47 has a hame-eye orientation. As the adhesive 45, an alloy having a low melting point (for example, an alloy of Bi, Pb, Sn, In, and Ga, a melting point of about 49 ° C.) is used. A scratch-preventing protective film 46 is interposed between the convex surface 2 a of the lens 1 and the adhesive 45. In order to join the lens 1 to the Yatoi 44 with the adhesive 45, for example, an apparatus called a layout blocker manufactured by LOH is used. As the Yatoi 44, those having different sizes according to the power of the lens 1, the outer diameter, and the curvature of the convex surface 2a are used.

  In FIG. 5, the rocking device 38 is attached to the upper end of a vertical rotating shaft 48 at a required angle (α) in the vertical direction, and the polishing jig 39 is detachably installed on the upper end surface. Yes. The rotating shaft 48 rotates around the axis during polishing. The swinging device 38 is configured to swing around the axis of the rotating shaft 48 when the rotating shaft 48 rotates. The inclination angle α of the swing device 38 with respect to the rotation shaft 48 is, for example, 5 °. FIG. 7 shows the trajectory 50 of the swinging movement of the swing device 38 and the polishing jig 39. The oscillating device 38 only revolves around the rotation shaft 48 in the swinging and swinging motion, and does not rotate.

  8 to 11, the polishing jig 39 has a balloon member 51 formed in a cup shape by an elastic material, and a lower surface side opening portion of the balloon member 51 is closed to hold the inside airtight. The fixture 52 and a valve 53 for supplying compressed air to the balloon member 51 are configured.

  The balloon member 51 is integrally extended to a dome portion 51A, a substantially elliptical cylindrical portion 51B integrally extending downward from the outer periphery of the dome portion 51A, and a lower end of the cylindrical portion 51B. It is comprised with the cyclic | annular inner flange 51C.

  The fixing member 52 is composed of two members, an inner fixing member 55 and an outer fixing member 56. By sandwiching the inner flange 51C of the balloon member 51 from the inner side and the outer side by these members, the lower surface side opening of the balloon member 51 is hermetically sealed. Is sealed. For this reason, a sealed space 57 is formed inside the balloon member 51. The inner fixture 55 is formed of an elliptical plate having the same size as the inner shape of the cylindrical portion 51B of the balloon member 51, and an annular groove 58 into which the inner flange 51C is fitted is formed on the outer peripheral portion of the lower surface.

  The outer fixture 56 is formed in a cup shape that opens upward, and thus includes a disk-shaped bottom plate 56A and a cylindrical portion 56B that protrudes integrally from the outer periphery of the upper surface of the bottom plate 56A. The inner fixture 55 is fitted and inserted into the cylindrical portion 56 </ b> B together with the cylindrical portion 51 </ b> B of the balloon member 51. The cylindrical portion 56 </ b> B has a circular outer shape, and an inner shape is formed in an elliptical shape having substantially the same size as the outer shape of the cylindrical portion 51 </ b> B of the balloon member 51. Then, after the inner fixing device 55 is integrally coupled by a plurality of set screws 60, the outer fixing device 56 is placed on the upper surface of the swinging device 38 in the reference axial direction of the balloon member 51 (the arrow in FIG. 7). F direction) is attached so as to coincide with the reciprocating movement direction (X direction in FIG. 5) of the arm 34, which is the reference axis direction of the surface to be polished 2b.

  The valve 53 is a check valve and is attached to the inner fixture 55.

  When compressed air is supplied to the sealed space 57 of the balloon member 51 via the valve 53, the dome portion 51A expands upward, and the average curvature of the cross section including the central axis of the dome portion 51A is in the minor axis direction (FIG. 7). The toric surface is maximum in the direction of arrow G) and minimum in the long axis direction (direction of arrow F). In this case, since the curvature of the dome portion 51A changes corresponding to the center height (vertex height) of the dome portion 51A, the dome portion 51A is measured and adjusted with an appropriate device to measure the height of the dome portion 51A. Can be set to a desired curvature.

  As shown in the plan view of FIG. 12, the polishing pad 40 includes a polishing portion 70 formed in an oval shape having a size substantially the same as the front view shape of the dome portion 51 </ b> A of the balloon member 51, and the polishing portion 70. It comprises a plurality of fixed pieces 71 extending outward from the periphery. The polishing portion 70 is composed of eight petal pieces 73 formed radially by a plurality of grooves 72 formed from the outer periphery toward the center. Each petal piece 73 is formed in a trapezoidal shape in plan view so that the width on the center side is narrow and the width on the outer peripheral side is wide. The fixed piece 71 is extended in the radial direction on the outer edges of a total of four petal pieces 73 located in the major axis direction and the minor axis direction among the eight petal pieces 73. The width of the fixed piece 71 is set narrower than the width of the outer edge of the petal piece 73. This is because the deformation of the balloon member 51 during the polishing and the bending of the fixing piece 71 when the fixing piece 71 is pulled out from a fastening member 76 described later are facilitated.

  If the width of the fixing piece 71 is too wide, the fixing piece 71 lacks flexibility and is difficult to bend. If the width is too narrow, the fixing piece 71 is weak in strength, and thus is easily broken during polishing. Therefore, the width of the fixed piece 71 is determined in consideration of strength and flexibility. For example, when a 1 mm thick felt is used, the width is preferably about 5 to 15 mm. If it is 5 mm or less, the durability is lowered, and if it is 15 mm or more, the flexibility is lowered and it becomes difficult to follow the deformation of the balloon member 51. As for two or more fixed pieces 71, it is desirable to arrange at fixed intervals. When the number of the fixing pieces 71 is too large, the contact area between the fixing pieces 71 and a fastening member 76 described later increases, and the pressure of the fastening members 76 applied to the fixing pieces 71 is dispersed and reduced, so that it is easy to come off. On the other hand, if the amount is too small, stable fixing of the polishing pad 40 to the polishing jig 39 cannot be obtained. From the above points, the number of the fixing pieces 71 is preferably about 3 to 5.

  The polishing pad 40 is detachably attached to the polishing jig 39 by the fastening member 76. The fastening member 76 is obtained by plastically deforming a wire spring having an appropriate thickness into a ring shape and superimposing both ends, and has a diameter smaller than the outer diameter of the outer fixture 56 in a natural state. The portions 76a and 76b are bent outward at substantially right angles.

  In order to attach the polishing pad 40 to the polishing jig 39, first, the dome portion 51A of the balloon member 51 is expanded into a predetermined dome shape by supplying compressed air, and then the polishing portion 70 of the polishing pad 40 is mounted thereon. Put. Next, both ends 76a and 76b of the tightening member 76 are sandwiched between fingertips, and the distance between the end portions 76a and 76b is reduced against elasticity, so that the tightening member 76 is enlarged in diameter. The fixing pieces 71 are pressed from above, and the fixing pieces 71 are bent downward and brought into contact with the outer periphery of the outer fixture 56. When the fingertips are released from both end portions 76a and 76b, the fastening member 76 returns to its original shape, and the fixing piece 71 is fastened and fixed to the outer periphery of the outer fixing tool 56, whereby the attachment of the polishing pad 40 is completed.

The lens 1 can be polished by the polishing apparatus 30 having such a structure by the following procedure.
First, the lens 1 is fixed to the block jig 37 on the lens mounting portion 36 of the arm 34. Next, a polishing jig 39 to which a polishing pad 40 is attached is installed on the upper surface of the rocking device 38. When attaching the lens 1 to the lens attachment portion 36, it is preferable to attach the lens 1 so that the reference axis direction of the polished surface 2b of the lens 1 coincides with the reciprocating movement direction of the arm 34 (the arrow X direction in FIG. 5). When installing the polishing jig 39 on the rocking device 38, it is preferable that the reference axis direction (F direction) of the balloon member 51 is set to coincide with the reciprocating movement direction (arrow X direction) of the arm 34.

  When the lens 1 is attached to the lens attachment portion 36, the lens 1 is lowered by the elevating device 41, and the polished surface 2 b is pressed against the surface of the polishing pad 40. In this state, an abrasive is supplied to the surface of the polishing pad 40, and the arm 34 is reciprocated in the left-right direction and rotated in the front-rear direction around the shaft 33. The movement trajectory of the lens 1 due to the movement of the arm 34 is shown in FIG.

  Further, as the rotating shaft 48 rotates, the swinging device 38 is swung as shown in FIG. By such movement of the lens 1 and the swinging device 38, the surface to be polished 2b of the lens 1 is polished by the polishing pad 40 and a polishing agent in a trackless polishing locus in which the polishing locus is slightly shifted every round. An optical surface having a surface shape is finished.

  The operation trajectory of the polishing jig during polishing is not limited to the above-mentioned trackless polishing trajectory, and as described above, the polishing jig is swung in a direction substantially perpendicular to the boundary between the excision region and the non-excision region. A period of time may be provided. For example, by reciprocating the arm 34 in the arrow X direction in FIG. 5 with the lens 1 attached to the polishing apparatus 30 so that the boundary line between the cut region and the uncut region is orthogonal to the arrow X direction in FIG. The polishing jig 39 can be swung in a direction perpendicular to the boundary line.

  Polishing of the surface to be polished may be performed by one-step polishing or may be performed by two or more steps. The surface cut by the curve generator may contain machining steps due to NC controlled backlash, etc. In that case, it is necessary to remove the machining steps by polishing to obtain an optical surface. There is. Therefore, in that case, it is preferable that the polishing step is a two-step polishing of rough polishing and final polishing. For example, in rough polishing, polishing abrasive grains having an average particle diameter of 1.6 to 1.8 μm can be used, and the temperature can be controlled to 8 to 14 ° C. for polishing. The polishing time can be 2 to 6 minutes, the polishing pressure can be 5 to 400 mbar, and the rotation speed can be 400 to 1000 rpm.

  Next, in the finish polishing, for example, polishing can be performed using a polishing abrasive having an average particle size of about 0.8 μm. The polishing time can be about 30 seconds to 1 minute, the polishing pressure can be 5 to 400 mbar, and the rotation speed can be 400 to 1000 rpm. In this way, the polishing step can be reliably removed by changing the polishing conditions.

  The lens after the polishing is subjected to subsequent processes such as removal of a dummy lens or film and a cleaning process. The removal of the film can be performed by a known method such as wiping with a solvent. Moreover, what is necessary is just to peel a tape from on a lens, when a masking tape is used as a film. For a semi-finished lens, a spectacle lens having both surfaces finished to optical surfaces can be obtained by performing processing for creating the other surface (non-optical surface) as an optical surface after slab-off processing. In this case, the removal of the dummy lens or the film may be performed before the creation of the optical surface or after the creation.

  According to the present invention described above, it is possible to provide a spectacle lens that has an excellent wearing feeling with adjustment of the prism action, and that has an excellent appearance without noticeable slab offline. A spectacle lens with a surface shape that allows first-order differentiation of the area including the slab offline has very little difference in level (step) between the slab-off processed area (removed area) and the unprocessed area (unremoved area), making slab offline easier It is a lens that is not visually recognized. According to the present invention, the surface shape can be realized by performing polishing using a polishing jig made of an elastic member after slab-off processing.

  The present invention will be further described below with reference to examples. However, the present invention is not limited to the embodiment shown in the examples.

[Example 1]
A slab-off process was applied to the concave surface of a progressive power lens (finished lens) having a convex surface on the object side and a concave surface on the eyeball side by the following procedure.
A curve generator that performs three-dimensional NC control after a commercially available protective tape (thickness: 20 μm) is attached to the entire surface of the concave optical center 3 mm below the concave optical center as shown in the right figure of FIG. 2 via an adhesive layer. A cutting process was performed. As a result, the area on the side of the distance portion that is not covered with the protective tape was spherically cut.
Next, a commercially available protective film was attached to the convex surface of the lens via an adhesive layer. Thereafter, the lens was fixed to a block jig as shown in FIG. For fixing the lens, an alloy blocker called a layout blocker made by LOH was used.
Next, a lens was attached to the polishing apparatus shown in FIG. 5 while being fixed to the block jig, and the polishing time shown in FIGS. 7 to 11 was a polishing time of 5 minutes, a polishing pressure of 200 mbar, a rotation speed of 530 rpm, and an average as an abrasive. Using a slurry in which alumina having a particle diameter of 0.8 μm was dispersed in water, polishing was performed with the trackless polishing locus described above. A polishing pad made of wool having a thickness of about 2 mm is used as the polishing pad, and a styrene-butadiene rubber having a hardness of 50 mm defined by JIS k 6253 (durometer type E) and a material thickness of about 3 mm is used as the balloon member. (SBR) was used.
Then, after removing the lens from the block jig, the protective tape was peeled off from the polished lens surface.

[Example 2]
The lens 1 was attached to the polishing apparatus 30 so that the boundary line between the cut region and the uncut region was orthogonal to the arrow X direction in FIG. In this state, a slurry in which alumina having an average particle diameter of 0.8 μm is dispersed in water is used as an abrasive, and the arm 34 is repeatedly moved back and forth in the direction of arrow X in FIG. The polishing jig 39 was swung in the direction of polishing (polishing time: 1 minute, polishing pressure: 200 mbar). Thereafter, the polishing process using the trackless polishing locus was performed in the same manner as in Example 1. Then, after removing the lens from the block jig, the protective tape was peeled off from the polished lens surface.

[Comparative Example 1]
A slab-off-processed lens was obtained by performing the same operation as in Example 1 except that a metal polishing dish having a spherical polishing surface was used as the polishing jig.

[Example 3]
A slab-off-processed spectacle lens was obtained by performing the same operation as in Example 1 except that a film was formed by the following method.
After affixing the protective tape used in Example 1 to a region excluding the region 3 mm below the optical center of the concave surface of the spectacle lens, the entire surface of the concave surface is coated by spin coating to a thickness of about 20 μm after curing. A commercially available acrylic UV curable resin was applied in an amount, followed by UV curing treatment to form a cured film. Thereafter, the masking tape was removed together with the cured film formed on the tape. As a result, a region 3 mm below the optical center could be covered with a cured film having a thickness of about 20 μm.

[Example 4]
The protective tape used in Example 1 is applied to the lower region (region below the dotted line in FIG. 4A) including the convex protrusion of the plastic bifocal lens having the cross-sectional shape shown in FIG. Thereafter, the same operation as in Example 1 was performed.

About Examples 1-4 and the comparative example 1, the prism refractive power in the distance measurement reference point before and behind slab-off process was measured with the lens meter, and it was confirmed that prism refractive power fell by slab-off process.
When the spectacle lenses obtained in Examples 1 to 4 and Comparative Example 1 were respectively worn under a fluorescent lamp, the presence of a slab offline was confirmed by others in the spectacle lens obtained in Comparative Example 1. In the eyeglass lenses 1 to 4, the visibility of the slab offline was so low that the presence of the slab offline could not be confirmed by another person during wearing.

For the spectacle lenses of Examples 1 to 4 and Comparative Example 1, the surface shape of the entire surface subjected to slab-off processing is a non-stylus type (contact type using a probe) surface shape measuring instrument (trade name UA-3P manufactured by Panasonic Corporation) Measured using In addition, although the said surface shape measuring device was used here, surface shapes can also be measured using techniques, such as an atomic force microscope. In Examples 1 to 4, the surface subjected to the slab-off process can be approximated by a function that can be first-order differentiated based on the obtained measurement data. There wasn't.
From the above results, it was shown that the spectacle lens having a surface shape in which the region including the slab offline can be first-order differentiated is a lens in which the slab offline is not easily visually recognized.

  From the above results, it was shown that according to the present invention, the prism action can be adjusted without impairing the appearance of various spectacle lenses.

  The present invention is useful in the field of manufacturing eyeglass lenses.

Claims (4)

A part of at least one surface of the spectacle lens is ablated by machining to perform a slab-off process for adjusting the prism action, and then polishing the ablation region surface;
In the state where the polishing jig surface made of an elastic material is covered with a polishing pad, the polishing process is performed while supplying an abrasive between the polishing pad surface and the ablation region surface, and the spectacle lens and the polishing jig A method for manufacturing a spectacle lens, wherein the eyeglass lens is moved relative to each other. A dome-shaped surface is formed by supplying a fluid to the inside of the polishing jig and expanding it,
The method for manufacturing a spectacle lens according to claim 1, wherein the polishing process is performed by covering the dome-shaped surface with the polishing pad. 3. The method for manufacturing a spectacle lens according to claim 1, further comprising a period in which the polishing jig is swung in a direction substantially orthogonal to a boundary between the cut region and the uncut region during the polishing process. The method for producing a spectacle lens according to any one of claims 1 to 3, wherein the slab-off processing is performed in a state where an area to be excised is uncoated on the surface and an area to be excised is covered with a film. .