JP2008158494A - Semifinished lens blank and manufacturing method thereof, and spectacle lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semifinished lens blank which is a semifinished lens blank having a diameter for a normal spectacle lens and with which the lens shape of a spectacle lens matching a wrap-around type spectacle frame can be secured and a manufacturing method thereof, and a spectacle lens using the same. <P>SOLUTION: The semifinished lens blank 2 whose surfaces are both spherical and which has prism refracting power on a geometric center line is manufactured by being molded by disposing an optical convex surface 111 and an optical concave surface 121 oppositely to each other so that the geometric centers of a first mold having the spherical optical convex surface 111 and a second mold having the spherical optical concave surface 121 are made to match each other and the semifinished lens black to be molded has the prism refracting power on the geometric center line. The spectacle lens 1 to be incorporated in the wrap-around type spectacle frame is manufactured by working the semifinished lens blank 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semi-finished lens blank used as a lens fabric of a spectacle lens incorporated in a spectacle frame having a large warp angle such as a wrap-around spectacle frame, a manufacturing method thereof, and a spectacle lens obtained from the lens blank.

  In recent years, wraparound type spectacle frames have been used mainly as sunglasses for sports. FIG. 9 shows a horizontal schematic cross-sectional view of an example of a wrap-around spectacle frame 200 in which the spectacle lens 100 is incorporated. As shown in FIG. 9, the wrap-around spectacle frame 200 has a feature that a warp angle is large and the eyeglass frame 200 is bent along the face. Therefore, it is used habitually by athletes as protective eyeglasses for sports and eyeglasses for eye protection.

  However, in the wrap-around spectacle frame 200, the lateral width of the lens 100 to be incorporated is considerably longer than that of normal spectacles. Further, as shown in FIG. 9, the nose side length from the position through which the visual axis, which is a normal line of sight in distance vision, passes to the edge on the nose side, and the ear from the position through which the visual axis passes to the edge on the ear side. The difference in side length is larger than normal spectacle lenses.

  Therefore, a semi-finished lens blank (hereinafter also simply referred to as semi-finish), which is molded thicker than the final lens in order to cut, grind and polish one side and optically finished on one side by transfer of the mold. As a lens fabric, after cutting, grinding, and polishing one surface, when trying to manufacture a spectacle lens that fits a wraparound spectacle frame by sculpting, the diameter of a normal semifinished lens blank for spectacles is too small This may cause a problem that the required target lens shape cannot be secured.

  As shown in FIG. 10A, a fitting point as a reference point exists at the geometric center of the front surface (object side surface) of a semi-finished lens blank used as a material for a single focus lens. As shown in FIG. 10 (b), the eyeglass lens 100 that has been processed into a lens shape so as to be incorporated into a wrap-around eyeglass frame is horizontally long and has a large ear-side portion, so that it is a semi-finished lens for ordinary eyeglasses. In the case of the diameter of the blank, there is a case where the end of the ear side protrudes and the lens shape of the lens suitable for the wraparound type spectacle frame cannot be secured.

  As shown in FIG. 10, by forming a semifinished lens blank having a diameter larger than that of a normal semifinished lens blank for normal glasses, it is possible to ensure the lens shape of the lens 100 that fits the wraparound type eyeglass frame. Although there is a wide part that can be scraped off without being used for the nose side part, the cost is greatly increased due to the great waste of material.

  The present invention has been made in view of the above circumstances, and it is possible to secure a lens shape of a spectacle lens that fits a wrap-around spectacle frame with a semi-finished lens blank having a diameter for a normal spectacle lens. It aims at providing the manufacturing method of a lens blank.

It is another object of the present invention to provide a semi-finished lens blank that can ensure a lens shape of an eyeglass lens that is suitable for a wraparound eyeglass frame while having a diameter for a normal eyeglass lens.
Another object of the present invention is to provide a spectacle lens that can be incorporated into a spectacle frame having a large warp angle from a semifinished lens blank having a diameter for a normal spectacle lens.

  In order to achieve the above object, first, the present invention aims to form a first mold having a spherical optical convex surface and a second mold having a spherical optical concave surface so that their geometric centers coincide with each other. The semi-finished lens blank is characterized in that the optical convex surface and the optical concave surface are arranged so as to face each other so as to have prism refractive power on the geometric center line.

  The present invention has been made by paying attention to the fact that the fitting point, which is a reference point, is decentered from the geometric center to the nose side in a spectacle lens incorporated in a wrap-around spectacle frame having a large warp angle. It is. That is, when casting the semi-finished lens blank, the optical centers of the molds for forming the convex and concave surfaces of the lens blank are shifted and decentered, and as a result, the geometric centers of the respective molds are mutually offset. A wrap-around type with a large warp angle in a semi-finished lens blank with a diameter for a normal spectacle lens by arranging the mold so as to give prism refractive power to the semi-finished lens blank obtained at the connecting geometric center line It has become possible to secure a lens shape of an eyeglass lens that fits the eyeglass frame. In the casting of a single focus semi-finished lens blank, prism refractive power cannot be given to the geometric center.

  Secondly, in the first method of manufacturing a semi-finished lens blank, the present invention provides the prism refractive power as a decentering amount of a fitting point from the geometric center of the semi-finished lens blank. A method for producing a semi-finished lens blank is provided.

  In a semi-finished lens blank with spherical surfaces, the amount of deviation of the fitting point from the geometric center, that is, the amount of decentration, can be optically expressed by the prism refractive power at the geometric center, and the amount of decentration is in the range of 1 to 15 mm. It will fit.

Third, the present invention relates to a method for producing the second semi-finished lens blank,
The amount of eccentricity is a parameter A that satisfies the following formula (1) expressed by a distance X between the pupils and a bridge length Y of a distance between the nose side edges of the left and right eyeglass lenses, a frame warp angle, A method of manufacturing a semi-finished lens blank characterized by being determined by a curvature.

    A = (X−Y) / 2 (1)

By using the parameter A that satisfies the above equation (1), the amount of eccentricity can be determined using the frame warp angle and the curvature of the lens.
Since the interpupillary distance X, the bridge length Y, the frame warp angle, and the lens curvature depend on the shape of the spectacle frame and the lens, the amount of eccentricity corresponding to each shape frame and lens can be obtained.

  Fourthly, the present invention provides the method for producing a semifinished lens blank according to any one of the first to third aspects, wherein the first mold and the second mold are made of glass, There is provided a method for producing a semifinished lens blank, wherein a molding surface is formed on an optical surface, and these non-molding surfaces are rotationally symmetric surfaces having the geometric center line as a symmetry axis.

  After assembling the two molds for forming the convex surface and the concave surface, it is determined whether the semifinished lens blank molded by these molds has a predetermined prism refractive power on the geometric center line. When two glass molds are used which are mirror-polished on both surfaces, and the non-molded surfaces on the outer surfaces of the two molds are rotationally symmetric surfaces with the geometric center line as the axis of symmetry, two sheets are molded. This is made possible by measuring the prism refractive power of the transmitted light on the geometric center line using the mold as a lens.

  Fifthly, the present invention provides a semi-finished lens blank characterized in that both convex and concave surfaces are constituted by spherical surfaces and have a prism refractive power on a geometric center line.

  The semi-finished lens blank, which has both convex and concave surfaces made of spherical surfaces and has prism refractive power on the geometric center line, is an eccentric lens whose fitting point is deviated from the geometric center, and is an eccentric lens with a large warp angle It is possible to secure a necessary area for a spectacle lens conforming to the above even at a normal diameter.

  Sixth, the present invention relates to a spectacle lens incorporated in a spectacle frame having a warp angle of 200 ° or more, which has prism refractive power on the geometric center line and has a double-sided spherical surface on the eyeball side. The spectacle lens is characterized in that the surface is polished and formed.

  A semi-finished lens blank having both surfaces composed of spherical surfaces and having a prism refractive power on the geometric center line is an eccentric lens blank whose fitting point is deviated from the geometric center, and the eyeball side surface of the eccentric lens blank is polished. Accordingly, it is possible to form an eccentric lens suitable for a spectacle frame having a large warp angle of 200 ° or more.

  Hereinafter, embodiments of the semifinished lens blank, the manufacturing method thereof, and the spectacle lens of the present invention will be described, but the present invention is not limited to the following embodiments.

  As shown in FIG. 1, the spectacle lens 1 of the present invention is a meniscus lens having a convex front surface (outer surface or object side refractive surface) 11 and a concave rear surface (inner surface or eyeball side refractive surface) 12. Also, the geometric center of the front surface (equal distance from two horizontal tangents and equal distance from two vertical tangents to fit a wrap-around type eyeglass frame with a large warp angle of 200 ° or more. This is an eccentric lens in which the fitting point is deviated from the nose side to the nose by a predetermined distance (eccentric amount). At the fitting point, the refractive power of the prism is almost zero, but at the geometric center line before the target lens processing (extension of the line connecting the geometric center of one surface of the lens and the geometric center of the other surface) is the amount of eccentricity. Prism power according to

  The front surface 11 of the spectacle lens 1 is, for example, a spherical surface, and the rear surface 12 is an aspheric surface that has been corrected so as to cancel the action of astigmatism caused by a sled angle or the action of a prism, for example, at the eye point through which the visual axis passes. Is formed. The spectacle lens 1 shown in FIG. 1 is a divergent lens called a minus lens, but may of course be a converging lens called a plus lens.

  The spectacle lens 1 is manufactured by using a semi-finished lens blank 2 indicated by a broken line as a lens fabric, cutting and grinding the inner surface thereof, performing mirror polishing, performing necessary processing as a spectacle lens, and further processing a lens. ing.

  With reference to FIG. 2, the amount of eccentricity of a spectacle lens incorporated in a spectacle frame having a warp angle of 200 ° or more will be described. FIG. 2 is a horizontal cross-sectional view schematically showing a state in which left and right eyeglass lenses 1 are incorporated into a wraparound eyeglass frame 200.

  As shown in FIG. 2, the warp angle of the spectacle frame 200 indicates an angle formed by the left and right rim surfaces. When the angle is less than 180 °, the warp state is inward, and when it is greater than 180 °, the warp state is outside. Call. The spectacle lens 1 of the present invention is suitable for spectacle frames in a sled state with a warp angle of 200 ° or more. The warp angle of commercially available wrap-around spectacle frames is generally in the range of 200 to 250 °. Examples of the spectacle frame having a warp angle of 200 ° or more include underwater spectacles and protective spectacles in addition to a wrap-around spectacle frame.

  As shown in FIG. 2, the spectacle frame 200 having a warp angle of 200 ° or more is bent along the face, and thus the spectacle lens 1 is fixed in a state inclined with respect to the visual axis. The visual axis is the direction in which the eyes are looking when they are gazing at an object that is straight ahead at the height of the eyes. The spectacle lens 1 incorporated in the spectacle frame 200 with a warp angle of 200 ° or more needs to have a larger curvature than a normal spectacle lens, and the curvature of the refractive surface on the object side is a refraction in a medium having a refractive index of 1.53. Expressed in terms of force, it is usually 5 diopters or more, and a range of 6 to 12 diopters is common.

  As shown in FIG. 2, the distance L between the nose side and the ear side from the geometric center line of the spectacle lens 1 to both end edges in the horizontal direction is equal. The distance between both edges in the horizontal direction is a lens width 2L. The visual axis is at a position close to the edge of the nose side from the geometric center line, and the position of the front surface corresponding to the point where the visual axis intersects the inner surface of the spectacle lens is a fitting point as a reference point. Therefore, the distance in the horizontal direction from the geometric center line to the fitting point is the amount of eccentricity. The amount of eccentricity of the spectacle lens 1 varies depending on the distance between the pupils, the bridge length of the distance between the nose side edges of the left and right spectacle lenses, the warp angle, the curvature of the front side of the spectacle lens, and the like.

The amount of eccentricity is determined as follows.
As shown in FIG. 6, the length of the parameter A is determined by the interpupillary distance X and the bridge length Y of the spectacle lens 1 (A = (XY) / 2). The lengths of the nose side required amount and the ear side required amount are determined by A, the frame warp angle, and the curvature of the lens. In other words, when the frame warp angle in FIG. 6 is α, the following equation holds for α and the required nose side amount l.

  lcosθ≈A = (XY) / 2

Note that l corrects the lens curvature, thereby determining the exact required amount on the nasal side and the required amount on the ear side.
The amount of eccentricity is half the difference between the required amount on the nasal side and the required amount on the ear side.
In the case of the wrap-around eyeglass frame 200 as in the present embodiment, the difference between the nose side required amount and the ear side required amount is large, so the semifinished lens closest to the obtained eccentric amount is selected.

  Thus, a spectacle lens suitable for a spectacle frame having a warp angle exceeding 200 ° as shown in FIG. 2 is an eccentric lens. The fitting point position of the semi-finished lens blank 2 matches the position of the specified fitting point when the geometric center of the frame and the spectacle lens is aligned when it is assembled into a spectacle frame with a warp angle exceeding 200 ° as shown in FIG. Set to do. However, in practice, it is not practical to mold semi-finished lens blanks having any eccentric amount, and therefore, one kind of eccentric amount of semi-finished lens blank can cope with an eccentric amount of a certain width.

  In the conventional semi-finished lens blank for single-focus spectacles, the fitting point coincides with the geometric center of the front surface. For example, the inner surface side of a semi-finished lens blank with a normal diameter is polished, the necessary processing is performed as a lens, the eyeglass lens fitting point is set to a position where the visual axis passes, and the lens shape is processed. There may be a problem that a large area cannot be secured.

  Therefore, in the present invention, focusing on the fact that a spectacle lens that fits a spectacle frame with a warp angle exceeding 200 ° is an eccentric lens, the semi-finished lens blank itself used as a lens fabric is made an eccentric lens, thereby warping the lens. It has been found that it is possible to secure a target lens region necessary for a spectacle lens suitable for a spectacle frame having a large corner even at a normal diameter. An eccentric lens in a lens having both spherical surfaces means that the lens has a refractive power on the geometric center line and the edge surface is uneven.

  Note that the semi-finished lens blank for a single focus lens with spherical surfaces does not add prism refractive power on the geometric center line, and is caused by a manufacturing error even if the prism refractive power exists. It is outside the common knowledge of those skilled in the art to intentionally add the refractive power of the prism.

  The prism and the amount of eccentricity have a relationship represented by the following formula. That is, the angle between the geometric center line and the line connecting the center of the inclined spherical surface having the center separated from the geometric center line and the geometric center line is represented by the prism apex angle θ, the radius of curvature of the spherical surface is represented by r, and the amount of eccentricity is represented by dx. When,

Sinθ = dx / r
The relationship is established. When a preferable range of the refractive power of the prism is expressed by an eccentric amount of the fitting point from the geometric center of the semi-finished lens blank, it is in the range of 1 to 15 mm, preferably in the range of 3 to 10 mm.

  The semi-finished lens blank 2 as an eccentric lens in which the fitting point is deviated from the geometric center is a lens fabric having a shape similar to a spectacle lens suitable for a spectacle frame having a large warp angle. For example, as shown in FIG. 3A, the shape of a conventional semi-finished lens blank in which the geometric center and the fitting point coincide is a rotationally symmetric shape with the geometric center line as the symmetry axis, and the inner surface side is cut and ground. The shape is created by.

  As shown in FIG. 3 (b), a rotationally symmetric conventional semi-finished lens blank having a geometric center line where the geometric center and the fitting point coincide with each other as a symmetry axis is displaced from the geometric center so that the inner surface is When the shape is created by cutting and grinding as indicated by the broken line, the thickness of the end portion on the ear side in the semi-finished lens blank may be insufficient for a spectacle lens for a spectacle frame having a large warp angle.

  As shown in FIG. 3C, in the semi-finished lens blank 2 of the present invention formed by deviating the fitting point from the geometric center line, the thickness is deviated, and the thickness at the position where the fitting point is set is larger than usual. The thickness on the opposite side of the geometric center line from the fitting point is increased. Therefore, the shape approximates the cross-sectional shape of the spectacle lens that fits the spectacle frame with a large warp angle. As a result, as shown by the broken line, when the shape is formed in a substantially spherical shape centered on one point on the line that passes through the fitting point and is parallel to the geometric center line, the thickness of the end side on the ear side in the semifinished lens blank becomes the warp angle. Therefore, it is possible to secure a spectacle lens suitable for a spectacle frame having a large warp angle even with a normal diameter by satisfying the thickness required for a spectacle lens for a large spectacle frame. Further, the amount of cutting / grinding is reduced, the processing time is shortened, the waste of materials is reduced, and the cost can be reduced.

  Next, the manufacturing method of the semifinished lens blank of this invention is demonstrated. FIG. 4 is a flowchart showing the first embodiment of the manufacturing process of the spectacle lens of the present invention, and each is a cross-sectional view. In the cast molding of the semi-finished lens blank, two molds, the first mold 110 and the second mold 120, are used. The 1st shaping | molding die 110 has the convex surface 111 which shape | molds the concave surface side of a semifinished lens blank, and the lower surface 112 of a non-molding surface. The 2nd shaping | molding die 120 has the concave surface 121 which shape | molds the convex surface side of a semifinished lens blank, and the upper surface 122 of a non-molding surface. Each of the first mold 110 and the second mold 120 has a planar shape that is a circle having the same diameter, and is generally made of glass with side surfaces formed on cylindrical surfaces.

  In the first mold 110 shown in FIG. 4A, the molding surface of the convex surface 111 and the bottom surface 112 are both formed into a spherical surface, the thickness is substantially uniform, and not only the convex surface 111 but also the bottom surface 112 is formed on the optical surface. It is a glass mold. The center of the spherical surface of the convex surface 111 and the center of the spherical surface of the bottom surface 112 both exist on the geometric center line, and the molding surface and the bottom surface 112 of the convex surface 111 are rotationally symmetric surfaces having the geometric center line as the symmetry axis.

  The second mold 120 is a glass mold in which the molding surface of the concave surface 121 and the upper surface 122 are both formed into a spherical surface, and not only the concave surface 121 but also the upper surface 122 is formed on the optical surface. The center of the spherical surface of the upper surface 122 is on the geometric center line, and thus is a rotationally symmetric surface with the geometric center line as the axis of symmetry. The center of the concave surface 121 is an inclined spherical surface shifted from the geometric center line toward the ear side. Therefore, the thickness of the second mold 120 is not uniform and the thickness is uneven. If both surfaces are made of a spherical surface and the thickness is uneven, prism refractive power is generated on the geometric center line of the lens. The fitting point set on the front surface of the lens as a reference point is set at a predetermined position on the side where the thickness of the second mold 120 is increased at a position away from the geometric center of the concave surface 121 of the second mold 120. ing. In addition, although not shown, a hidden mark for informing the position of the reference fitting point is stamped on the concave surface 121 of the second mold 120, for example, on both sides of a straight line that is equidistant from the fitting point, so that the semi-finished lens blank 2 The image is transferred to the front surface 21.

  As shown in FIG. 4B, the first mold 110 and the second mold 120 are separated from each other by a predetermined distance with the convex surface 111 of the first mold 110 and the concave surface 120 of the second mold 120 facing each other. If the side surfaces of the two molds 110 and 120 are aligned so that the side surfaces coincide with each other, the geometric center lines of the two molds 110 and 120 are aligned with each other. Then, the adhesive tape 130 is wound one or more times so as to straddle these side faces while maintaining the positions of the first mold 110 and the second mold 120, and the first mold 110 and the second mold 120 are mutually positioned. At the same time, the cavity between the first mold 110 and the second mold 120 is sealed with the adhesive tape 130 to form the cavity 140, and the lens casting mold 150 is assembled. . The thickness of the cavity 140 is the maximum of the center thickness and edge thickness of all lenses created by cutting the molded semi-finished lens blank, and satisfies the maximum center thickness and the maximum edge thickness at that time. It is prescribed to

  The molding die 150 assembled in this way is a spherical surface in which the lower surface 112 and the convex surface 111 of the first molding die 110 and the upper surface 122 of the second molding die 120 are centered on the geometric center line, and the concave surface of the second molding die 120. Only the spherical surface 121 is an inclined spherical surface whose center does not coincide with the geometric center line.

  The semi-finished lens blank molded by such a mold 150 is composed of spherical surfaces on both sides and the spherical surface of the convex surface 21 is inclined. Therefore, the semi-finished lens blank has prism refractive power on the geometric center line and has a side surface (edge surface). ) Is an eccentric lens with a bias in thickness.

  Since both sides of both the first mold 110 and the second mold 120 are also formed on the optical surfaces in the mold 150 itself, the first mold 110 and the second mold 120 function as lenses. Since the second mold 120 is a decentered lens, the same prism refractive power is produced on these geometric center lines as when the first mold 110 and the second mold 120 are arranged as lenses. The prism refracting power of the mold 150 is proportional to the prism refracting power of the semifinished lens blank 2 to be obtained, although the value is different. Therefore, by measuring the prism refractive power of the transmitted light at the geometric center line of the assembled mold 150, it can be determined whether or not the assembled mold 150 is eccentric with a predetermined amount of eccentricity.

  Next, the lens material is filled in the cavity 140 of the sealed space surrounded by the first mold 110, the second mold 120, and the adhesive tape 130 of the mold 150, and the lens material is polymerized and cured by light energy or heat energy. Then, semi-finished lens blank 2 is formed.

  After polymerization and curing, the adhesive tape is peeled off, and the first mold 110 and the second mold 120 are separated from the obtained semifinished lens blank 2, and as shown in FIG. 4 (c), the semifinished lens blank is obtained. 2 can be obtained. This semi-finished lens blank 2 is an eccentric lens in which the convex surface 21 and the concave surface 22 are spherical surfaces, have a prism refractive power on the geometric center line, and the fitting point is deviated from the geometric center to the nose side. A longitudinal section passing through the geometric center line and a point passing through the position where the front fitting point is set is the direction in which the thickness is most varied.

As shown in FIG. 4D, the concave surface side (eyeball side) 22 of the obtained semifinished lens blank 2 is cut, ground, and mirror-polished to form a predetermined optical surface. Since the prism 12 has a refractive power of almost zero at the fitting point, for example, the astigmatism caused by the sled angle and the action of the prism, etc. caused by the slant angle from the eye point passing through the visual axis become uneven. It is formed on an aspherical surface that has been corrected to cancel. Fits a wrap-around type spectacle frame having a convex front surface 11 (21) of the optical surface transferred by the concave surface 121 of the second mold 120 and a concave rear surface 12 whose shape is created on the optical surface by polishing. A spectacle lens 1 is obtained. Since the hidden mark for determining the reference point is transferred to the front surface 11 of the obtained semifinished lens blank 2 during the processing, the processing reference point can be determined from the hidden mark. After that, for example, through a process such as a dyeing process, formation of a hard coat layer, and formation of an antireflection film, the lens is supplied to a store as a completed lens. In a store, a lens is processed to fit the frame of the spectacle lens, and the spectacle is provided in the spectacle frame.

  In the manufacturing method according to the first embodiment, the concave surface 121 of the second mold 120 for performing casting is inclined, and the front surface 21 of the semifinished lens blank 2 is formed by the transfer of the concave surface 121. By providing the concave surface 121, there is an advantage that the semi-finished lens blank 2 can be transferred to the front surface 21 that is not polished, and the positioning of the processing can be accurately performed.

  In the manufactured semi-finished lens 2, it is necessary to confirm whether the nose side required amount and the ear side required amount of the spectacle lens 1 are secured. As shown in FIG. 7, the nose side amount and the ear side amount of the semi-finished lens 2 satisfy the following expressions, and the nose side amount and the ear side amount of the semi-finished lens 2 are respectively the required nose side amount of the spectacle lens 1. As long as it is larger than the ear-side required amount.

Nose side amount = (lens diameter of semi-finished lens 2/2) −Eccentric amount Ear side amount = (lens diameter of semi-finished lens 2/2) + Eccentric amount

  Furthermore, as shown in FIG. 8, if there is frame information, an accurate amount and direction of eccentricity can be obtained, and the semifinished lens 2 can be manufactured such that the lens width of the spectacle lens 1 is accommodated. .

  Next, a manufacturing method according to the second embodiment of the present invention will be described with reference to the flowchart of FIG. A first molding die 110b for performing cast molding of the semifinished lens blank shown in FIG. 5A has a convex surface 113 for molding the concave surface side of the semifinished lens blank 2b and a lower surface 114 of a non-molding surface. The 2nd shaping | molding die 120b has the concave surface 123 which shape | molds the convex surface side of the semifinished lens blank 2b, and the upper surface 124 of a non-molding surface. Each of the first mold 110b and the second mold 120b has a planar shape of a circle having the same diameter, and is usually made of glass.

  A first mold 110b shown in FIG. 5A is a spherical surface having a bottom surface 114 centered on a geometric center line, a rotationally symmetric surface having the geometric center line as a symmetry axis, and is formed on an optical surface. . The convex surface 113 is formed as a spherical surface, but the center is an inclined surface that is spaced apart from the geometric center line toward the nose, and the thickness increases toward the side where the set fitting point is located. It is formed in a lens shape. The first mold 110b has prism refractive power on its geometric center line.

  The second mold 120b is a spherical surface having both the molding surface of the concave surface 123 and the upper surface 124 centered on the geometric center line, and is a rotationally symmetric surface with the geometric center line as an axis of symmetry, and has a substantially uniform thickness. In addition, not only the concave surface 123 but also the upper surface 124 is a glass mold formed on the optical surface. The fitting point set on the front surface of the lens as a reference point is that the thickness of the first mold 110b increases at a position away from the geometric center of the concave surface 123 of the second mold 120b to the nose side, and the cavity gap gradually decreases. It is set to a predetermined position on the side that is being operated.

  As shown in FIG. 5A, the first molding die 110b and the second molding die 120b are separated from each other by a predetermined distance with the convex surface 113 of the first molding die 110b and the concave surface 123 of the second molding die 120b facing each other. If the side surfaces of the two molds 110b and 120b are aligned so that the side surfaces coincide with each other, the geometric center lines of the two molds 110b and 120b are aligned with each other. Then, the adhesive tape 130 is wound one or more times so as to straddle these side surfaces while maintaining the positions of the first mold 110b and the second mold 120b, and the first mold 110b and the second mold 120b are mutually positioned. At the same time, the cavity 140b is formed by sealing the gap between the first mold 110b and the second mold 120b with the adhesive tape 130, and the lens casting mold 150b is assembled. .

  The prism refractive power of the transmitted light at the geometric center line of the assembled mold 150b is measured, and it is determined whether or not the assembled mold 150b is eccentric with a predetermined eccentricity.

  Next, as shown in FIG. 5B, the lens raw material 160 is filled in the cavity 140b of the sealed space surrounded by the first mold 110b, the second mold 120b, and the adhesive tape 130 of the mold 150b. The lens raw material 160 is polymerized and cured with energy or thermal energy to form the semi-finished lens blank 2b.

  After the polymerization and curing, the adhesive tape 130 is peeled off, and the first mold 110b and the second mold 120b are separated from the obtained semifinished lens blank 2b, and as shown in FIG. 5 (c), the semifinished lens A blank 2b can be obtained. This semi-finished lens blank 2b is a decentered lens in which the front surface of the convex surface 23 and the rear surface of the concave surface 24 are spherical surfaces, have prism refractive power on the geometric center line, and the fitting point is deviated from the geometric center to the nose side. It is. A longitudinal section passing through the geometric center line and a point passing through the position where the front fitting point is set is the direction in which the thickness is most varied.

  As shown in FIG.5 (d), the concave surface 24 of the obtained semifinished lens blank 2 is cut and ground, and is mirror-polished to form a predetermined optical surface. A spectacle lens 1b adapted to a wraparound spectacle frame having a convex front surface 11 (23) of the optical surface transferred by the second mold 120b and a concave rear surface 12 whose shape is created on the optical surface by polishing. Get. After that, for example, through a process such as a dyeing process, formation of a hard coat layer, and formation of an antireflection film, the lens is supplied to a store as a completed lens. In a store, a lens is processed to fit the frame of the spectacle lens, and the spectacle is provided in the spectacle frame.

  In the above description, the mold is assembled by the tape molding method using an adhesive tape, but a method using a gasket may be used. In addition, the inner surface side (eyeball side) of the semifinished lens blank is described as being polished, but the outer surface side (object side) may be polished. As the predetermined optical surface to be formed, a spherical surface, an astigmatism surface, a progressive refraction surface, an aspheric surface, a surface combining two or more of these, and the like can be considered.

The semi-finished lens blank of the present invention can be used as a lens fabric for manufacturing a spectacle lens to be incorporated into a wraparound type spectacle frame.
The method for producing a semi-finished lens blank of the present invention can be used for production of such a semi-finished lens blank.
The spectacle lens of the present invention can be used by being incorporated into a wrap-around spectacle frame.

It is sectional drawing which shows an example of the spectacle lens of this invention. 1 is a schematic horizontal sectional view of a wrap-around type spectacle frame incorporating a spectacle lens. (A)-(c) is a conceptual diagram explaining the example which cuts the inner surface side of a semifinished lens blank. (A)-(d) is a flowchart shown with sectional drawing explaining 1st Embodiment of the manufacturing method of the semifinished lens blank of this invention. (A)-(d) is a flowchart shown with sectional drawing explaining 2nd Embodiment of the manufacturing method of the semifinished lens blank of this invention. 1 is a schematic horizontal sectional view of a wrap-around type spectacle frame incorporating a spectacle lens. It is a top view which shows the required amount of a semifinished lens blank. It is a top view which shows the amount of eccentricity and the eccentric direction of a semifinished lens blank. It is a horizontal schematic cross-sectional view of a wraparound-type spectacle frame incorporating a spectacle lens. (A) And (b) is a conceptual diagram explaining the diameter of the semifinished lens blank which ensures the lens shape of the spectacle lens for wraparound type spectacle frames.

Explanation of symbols

  1: spectacle lens, 11: front surface, 12: rear surface, 2, 2b: semi-finished lens blank, 21: convex surface (outer surface), 22: concave surface (inner surface), 110: first mold, 111: convex surface, 112: bottom surface , 120: second molding die, 121: concave surface, 122: top surface, 130: adhesive tape, 150: molding die, 200: wraparound type spectacle frame

Claims (6)

A semi-finished lens blank to be molded with a first mold having a spherical optical convex surface and a second mold having a spherical optical concave surface having the same geometrical center and to be molded has a prism refractive power on the geometric center line. A method for producing a semi-finished lens blank, wherein the optical convex surface and the optical concave surface are arranged so as to face each other so as to have a shape. In the manufacturing method of the semi-finished lens blank according to claim 1,
A method of manufacturing a semi-finished lens blank, wherein the prism refractive power is in the range of 1 to 15 mm when expressed by an eccentric amount of a fitting point from the geometric center of the semi-finished lens blank. In the manufacturing method of the semi-finished lens blank according to claim 2,
The amount of eccentricity is a parameter A that satisfies the following formula (1) expressed by a distance X between the pupils and a bridge length Y of a distance between the nose side edges of the left and right eyeglass lenses, a frame warp angle, A method of manufacturing a semi-finished lens blank, characterized by being determined by a curvature.
A = (X−Y) / 2 (1) In the manufacturing method of the semi-finished lens blank in any one of Claims 1-3,
The first molding die and the second molding die are made of glass, and the respective non-molding surfaces are formed as optical surfaces, and these non-molding surfaces are rotationally symmetric surfaces having the geometric center line as an axis of symmetry. A method for producing a semi-finished lens blank. A semi-finished lens blank characterized in that both surfaces of a convex surface and a concave surface are constituted by spherical surfaces and have a prism refractive power on a geometric center line. A spectacle lens incorporated in a spectacle frame having a warp angle of 200 ° or more, which is formed by polishing a surface on the eyeball side of a semifinished lens blank having prism refractive power on a geometric center line and having both surfaces made spherical. An eyeglass lens characterized by that.

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