JP2003103401A - Manufacturing method for optical lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for an optical lens, capable of precisely cutting an optical resin material without polishing work after cutting. SOLUTION: An ion generator 1 is used as a static electricity preventing device to prevent the chips of the optical resin material 4 generating during the cutting operation from electrostatically adhering to a lens machining surface and a turning tool 5. The chips are removed sequentially by a suction pipe during the operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical lens by processing an optical resin material, and more particularly, to a method for manufacturing an ophthalmic lens such as a contact lens and an intraocular lens by cutting. The present invention relates to a manufacturing method using an antistatic means for preventing material chips generated in a cutting process from adhering to a lens processing surface and / or a cutting tool due to static electricity.

[0002]

2. Description of the Related Art Conventionally, in the method of manufacturing an optical lens, a molten resin is injection-molded in a mold forming a space corresponding to the lens shape, or a lens space is formed by a resin mold. There is a method in which a polymerizable monomer is poured in to polymerize a lens, and a method in which an optical resin material is cut into a desired shape.

The method of directly molding a final product into a lens shape in a mold and the method of polymerizing a polymerizable monomer in a resin mold enable mass production because the manufacturing process can be simplified. In order to manufacture lenses having various standards, it is necessary to provide molds and molds corresponding to them, and there is a problem in maintenance and management. On the other hand, in the method of cutting the optical resin material into a lens by cutting, it is slightly inferior in terms of mass production because it requires more steps than the case of using the above-mentioned mold or mold in the number of steps, It is convenient for producing a wide variety of different standard lenses.

In the manufacturing method by cutting of contact lenses and the like, an optical resin material is fixed to a rotating main shaft of a cutting device, and a cutting tool is pressed from the outer surface so that a desired curved surface can be obtained. There is a fixing portion called a chuck for fixing to the main shaft, and for example, there are (a) drawbar type chuck (b) vacuum type chuck and the like. Here, the drawbar type chuck is to fix the peripheral part other than the lens processing part by grasping the peripheral part with a plurality of claws, and a drawbar for controlling the opening and closing of the claw part is inserted in the rotating main shaft.

On the other hand, the vacuum type chuck is a cylindrical chuck having a gas passage bored along the central axis of the main shaft.
One end of a main shaft for transmitting a rotational force from the rotation drive unit to the chuck is connected to the chuck. A gas passage communicating with the gas passage of the chuck is formed in the main shaft along the central axis, and an air suction device communicating with the gas passage is provided on the other end side of the main shaft. Therefore, if a resin material is placed at the end of the chuck to block the gas passage and the air suction device is activated, the inside of the gas passage becomes a negative pressure and the resin material is fixed by being sucked at the end of the chuck. It The optical resin material which is fixed to the cutting device by the fixing method of the draw bar type chuck or the vacuum type chuck and is cut is transferred to the polishing step to improve the processed surface accuracy of the surface and completed as an optical lens. . Since these steps are performed, the manufacturing time becomes longer than that in the case of molding a lens by using a mold / mold, which is an obstacle to mass production.

By the way, in the conventional cutting process, a resin material is fixed, a main shaft is rotated, and a diamond cutting tool is pressed against the resin processed surface to scrape off the material to form a curved surface. Although it is formed, in the case of the vacuum type chuck, the material cannot be fixed unless the suction force is stronger than the force when shaving the material by pressing the bite, and if it sucks too much, it will be thinly processed. In that case, there is a problem that the resin material loses its suction force and is deformed, and the drawbar type has been considered to be superior in terms of stable fixation of the resin material. In the case of a drawbar type chuck, when the drawbar rotates synchronously with the main spindle, the inner surface of the main spindle often comes into contact with the main spindle, and as a result, the vibration generated during that time affects the finished state of the machined surface. Japanese Patent Laid-Open No. 4-129607
Japanese Unexamined Patent Publication No. 6-170624 discloses a cutting device that reduces the influence of these vibrations. By processing with a diamond bit of higher accuracy using these devices, it has become possible to obtain a lens material having a surface accuracy of a level practically no problem even if the conventionally required polishing step is omitted. . However, as a problem caused by the improvement of the mechanical device, resin chips generated by cutting adhere to the lens processing surface and the cutting tool due to static electricity, and these secondarily scratch the lens surface, or It had problems such as shortening the life of the cutting tool. Of course, conventionally, this chip has been removed by suctioning it with a vacuum device through a suction pipe and installing the open end of the suction pipe in the immediate vicinity of the cutting tool, but the chip tends to be charged with static electricity, After being scraped off, each of them is likely to scatter in an appropriate direction (further, the wind generated by the rotation of the main shaft also had an effect), and in the past it was premised on polishing after cutting, so some chips There is also a circumstance that the effect of the scattering and adhesion of was not a big problem.

[0007]

SUMMARY OF THE INVENTION The present invention improves the surface accuracy of the lens surface after cutting when fixing the optical resin material to a cutting device and cutting the surface of the material to form a lens shape. An object of the present invention is to provide a method for manufacturing an optical lens, which can reduce the manufacturing cost by reducing the number of steps by eliminating the subsequent polishing step, and can be mass-produced by cutting.

[0008]

In order to achieve the above object, the present invention is characterized by having the following constitution. That is, when the optical resin material is fixed to a cutting device and the surface of the material is cut to form a lens shape, chips of the material generated by cutting do not adhere to the lens processing surface and / or the cutting tool. The present invention relates to a method for manufacturing an optical lens, which is characterized in that a processed portion is processed while using an antistatic means to produce an antistatic effect. The static electricity prevention means does not generate static electricity on the chips generated by processing the lens while using a device that emits ions, or has the effect of diminishing the static electricity, and as a result, prevents the chips from adhering and attracts them. Chips during the machining process are sequentially removed by a pipe, and suction removal is performed so as not to remain on the lens surface or the like.

The optical resin material of the present invention may be any material as long as it exhibits the function of an optical lens and can be machined, for example, methyl (meth) acrylate, ethyl (meth) acrylate and the like. Polyalkyl (meth) acrylate resin, styrene monomer,
Silicone-containing monomer, fluorine-containing monomer, N vinylpyrrolidone, dimethylacrylamide, etc. It does not matter whether it becomes or remains hard.

The resin selected from the above-mentioned various materials may be used, for example, when the constituent monomers are polymerized into a rod-like or plate-like shape and then cut into a round bar to be cut into a disc-shaped lens block and then fixed to a cutting device. In some cases, a lens block shaped polymer is fixed to a cutting device, and in another case, one of the lens optical surfaces formed in advance by a mold is fixed and the other surface is cut. When a rod-shaped or plate-shaped resin material is carved out to make a lens block and the lens block is further finished, there are many parts to be machined, so a lot of chips are generated by cutting, and the machining bite is greatly exhausted. Cut the polymerized lens shape or complete one lens surface by molding,
It is preferable that the other surface is manufactured by a method in which a finished product can be obtained by shaving a small amount.

A contact lens has an inner surface and an outer surface, but in the case of a soft contact lens, the curvature of the inner surface is 1 in particular.
There may be only two kinds, and the visual acuity is corrected by forming various curvatures on the outer surface side according to the diopter of the patient. By molding the inner surface of this lens with a mold, the process of processing the inner surface can be reduced, and by cutting the outer surface, lenses corresponding to various standards can be manufactured, so the number of molds and molds can be reduced and maintained. Management can be facilitated. In other words, when the lens material is polymerized by the combination of the convex mold and the concave mold, the concave mold is designed to be slightly thicker than the desired lens thickness, the inner lens surface is transferred from the convex mold, and the outer lens surface is removed from the concave mold. By giving a desired curvature by cutting the lens material later, a multi-standard lens can be obtained from a combination of convex-concave surface molds of the same standard. The method of cutting both sides after superimposing into a lens block shape may be considered in the same manner as above, and since the lens inner surface side is also cut, it is possible to manufacture lenses of multiple standards (the cutting amount on both sides at this time is Design the curvature of both molds so that it is as small as possible). In these methods, the resin used in the mold is appropriately selected from, for example, polyethylene, polypropylene, ethylene vinyl acetate, propylene copolymer, polystyrene, nylon, etc. by general injection molding or thermocompression molding so that it is inexpensive and easy to handle. Composed of thermoplastic material. If processing is performed with the lens material fixed to the mold, even vacuum type chucks can be cut without deforming the lens material due to suction force, and even draw bar type chucks can be easily used by using the mold part. Can be fixed to the cutting device. By using the antistatic device of the present invention at the time of these cutting processes, the generated chips are sufficiently removed. The removal of chips is effective not only for preventing secondary damage from occurring on the lens processed surface, but also for prolonging the life of the expensive diamond tool and preventing scattering of cutting chips in the manufacturing environment. Further, the present invention preferably exerts its effect in a method of obtaining a finished lens by performing only a cutting process without performing a polishing step. Therefore, the cutting device itself can obtain a machined surface with high precision. Is desirable.

In general, the antistatic means is (a) a spray containing an antistatic agent (for example, Kobayashi Pharmaceutical Co., Ltd .; antistatic agent-containing deodorant spray “Krinshu”; Nippon Riva Co., Ltd .; electrostatic charging). A method of spraying an antistatic agent-containing softening agent such as "Super Furfa 1/6") to prevent the chips from being charged, (b) an antistatic spray device (for example, Meiki Resin Industry Co., Ltd .; "MEC-302C") ) Method,
(C) Corona discharge type ion generator (for example, manufactured by Kyox Co., Ltd .; ion generator "KI blow", manufactured by Kyoritsu ATS Co., Ltd .; ionizer nozzle for static elimination and dust removal, manufactured by Takasago Thermal Engineering Co., Ltd .; Super Clean) Ionizer "T
SCI series ", manufactured by Kasuga Electric Co., Ltd .; direct current type static elimination" KD-110 "etc.), (d) UV irradiation type ion generator (for example, manufactured by Takasago Thermal Engineering Co., Ltd .; Super Cleaner ionizer) And (e) a static eliminator by grounding (e.g., Koken Co., Ltd .; electrostatic antistatic "escape ground type airline mask").

Among the above means (a), it is necessary to spray only the chips so that the spray content does not adhere to the surface of the lens material, and when the lens is continuously manufactured, Not practical because it requires a large amount of spray. However, in the case of manufacturing one product, there is no need to purchase a device as compared with other means, so that it can be easily tried. The antistatic spraying device of (b) is similar to that of (a) and is not preferable because the sprayed product may adhere to the lens.
In the corona discharge type ion generator of (c), by applying a high voltage to the discharge electrode, a corona discharge is generated at the discharge electrode, the air molecules are ionized, and these ions float in the air, Neutralizes static electricity generated by contact with chips. As a result, chips do not adhere to the lens processing surface or the diamond cutting tool as compared with the conventional method in which chips are simply sucked, and chips are sandwiched between the resin material and the cutting tool and the processing surface is scratched. Without turning on
A good optical lens can be obtained while maintaining the surface precision during processing. The ultraviolet irradiation type ion generator of (d) is one in which molecules in the air are ionized by ultraviolet irradiation, and is preferably used in the present invention similarly to (c). (E)
The static eliminator based on grounding cannot be expected to be effective for objects such as chips that are scattered in the air. Therefore, (c) and (d) can be preferably used in the present invention. Of these, the DC type static eliminator "KD-110" manufactured by Kasuga Electric Co., Ltd. is preferably used because of its price, small size, and easy handling.

By using the above-mentioned antistatic cutting, the chips will not adhere to the lens processing surface or the diamond cutting tool as compared with the case where the cutting chips are simply sucked, and the resin material and the cutting tool It is possible to obtain a good optical lens in which the surface accuracy at the time of processing is maintained without chips being sandwiched between and scratching the processed surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be specifically described below with reference to the above contents with reference to the accompanying drawings.

The figure shows a schematic diagram in which a corona discharge type ion generator (manufactured by Kasuga Electric Co., Ltd .; DC type static eliminator "KD-110") 1 is attached toward a cutting portion of a cutting device 2. A lens material 4 is fixed to the tip of the lens fixing portion 3 and is cut by a cutting tool 5. As indicated by the movement of the arrow, the lens material 4 rotates about the main axis 6,
Further, the cutting tool 5 is configured so as to be able to move back and forth in a direction toward and away from the lens material direction and also to perform a swiveling motion. An open end of a hollow pipe 7 connected to a suction pump (not shown) is close to the cutting bite 5, and chips generated by cutting due to suction force from the pump are collected from a processing portion. The ion generator 1 is attached at a position where it falls on the entire cutting portion, and an antistatic effect on chips is produced.
When the ion generator was operated for cutting, chips were collected by a suction pump without remaining in any of the processed parts, and a lens having the same surface accuracy as the processed surface was obtained. However, when cutting was performed without operating, some of the chips remained on the cutting bite and could not be removed by suction alone. Further, there is a case where chips are sandwiched between the cutting tool and the lens processed surface, and the processed surface is scratched by friction.

Among the above devices, for example, the structure of the lens fixing part may be a draw bar type having a collet chuck composed of a plurality of claw parts, or a vacuum type chuck having a gas passage inside the fixing part. It may be.
The lens material to be fixed may be manufactured from a lens block cut out from a plate material, a rod material, or the like, or may be formed by molding one surface and molding the other surface.

[0018]

As described above, according to the cutting method using the antistatic means of the present invention, an antistatic effect can be obtained for the generated chips, and the chips can be used as a lens processing surface or a cutting tool. It is possible to provide a lens processing method that removes dust without adhering and has high surface accuracy.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state in which an antistatic device according to the present invention is attached.

[Explanation of symbols]

1 Ion generator 2 cutting equipment 3 Lens fixing part 4 Lens material 5 cutting tool 6 spindle 7 Hollow pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02C 7/04 G02C 7/04 (72) Inventor Mikio Kinoshima Asahi, Genji-gun, Gujo-gun, Gifu Pref. 15 Shimizu Gifu factory F-term (reference) 2H006 BC07 3C045 AA10 CA18 HA02 HA10

Claims (3)

[Claims] 1. When an optical resin material is fixed to a cutting device and the surface of the material is cut to form a lens shape, chips of the material generated by the cutting do not adhere to the lens processing surface and / or the cutting tool. In addition, the method for manufacturing an optical lens is characterized in that the processed portion is processed while using an antistatic means to produce an antistatic effect. 2. The method for manufacturing an optical lens according to claim 1, wherein the antistatic means is based on ion radiation to chips. 3. The manufacturing method according to claim 1, wherein the optical lens is an ophthalmic lens such as a contact lens and an intraocular lens.