JP3771636B2 - Optical transmission body and manufacturing method thereof - Google Patents

Description

【０１１８】
【発明の効果】
本発明の光伝送体は外周部の屈折率分布が不整な部分に光吸収剤または光散乱剤がほぼ均一な濃度で存在するためにフレア光を効率的且つ簡単に抑制することができ、解像度の高いレンズ、レンズアレイを提供することができる。
【０１１９】
また、本発明の製法によれば光伝送体中に光吸収剤または光散乱剤を容易に混在させることができる。また、この製法は溶剤を用いないので、光伝送体内部に溶剤が残留してレンズ性能が経時変化するという問題も生じさせない。
【図面の簡単な説明】
【図１】本発明の光伝送体の縦断面図である。
【図２】図１の光伝送体の横断面図である。
【図３】本発明の他の態様の光伝送体の縦断面図である。
【図４】図３の光伝送体の横断面図である。
【図５】本発明の光伝送体を製造するための製造装置の概略図である。
【図６】光伝送体の解像度（ＭＴＦ）測定装置の概略を示す図である。
【図７】ＣＣＤセンサーにより解像度を測定した図である。
【図８】本発明で用いるＣＹー１０の吸収特性を示す図である。
【図９】本発明で用いるＢｌｕｅ ＡＣＲの吸収特性を示す図である。
【符号の説明】
１ レンズ素材
２ 光吸収剤または光拡散剤
３ 光吸収剤または光拡散剤が存在しない最外周部
１０ 同心円状複合ノズル
１１ 未硬化の糸状体
１２ 相互拡散部
１３ 硬化処理部
１４ 引き取りローラー
１５ 光伝送体
１６ 巻き取り部
１７ 不活性ガス導入口
１８ 不活性ガス排出口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic optical transmission body that can be used as various optical transmission paths such as a light focusing optical fiber, a light focusing rod-like lens, and a light sensor, and a method for manufacturing the same.
[0002]
[Prior art]
An optical transmission body having a continuous refractive index distribution therein has already been proposed in Japanese Patent Publication No. 47-816. A synthetic resin body has been proposed in Japanese Patent Publication No. 47-28059. Thereafter, optical transmission bodies made of glass or synthetic resin have been proposed by various methods. In general, the gradient index optical transmission body is mirror-polished to a parallel plane perpendicular to the central axis at both end faces, and used alone as a microlens. Many of them are closely arranged and bonded and integrated to form a lens array, which is widely used as a line sensor component for copying machines, facsimiles, scanners, etc., and for a writing device of an LED printer. In a specific application, one end surface or both end surfaces are used as spherical surfaces having a slight curvature. In the gradient index lens and lens array used for image transmission, a lens having high resolving power and excellent optical characteristics is required, and so-called flare light becomes a problem in obtaining high resolving power and good image contrast. .
[0003]
In a gradient index lens, a light beam incident from one end face travels in a sine curve in the lens body and exits from the other end face to form an image. In general, the refractive index distribution in the lens body is not always ideal. It is not consistent with the distribution. In particular, it deviates from the ideal distribution near the outer periphery, and contributes to image formation called flare light around the lens due to distortion of the refractive index distribution near the outer periphery and external light entering the lens through the lens side peripheral surface. Does not generate blurry light. This flare light adversely affects the resolving power of the lens and the contrast of the image.
[0004]
In order to prevent the occurrence of flare light as described above, the outer peripheral surface of a gradient index lens element used in a lens array has been conventionally made into a rough surface with fine irregularities by chemical etching or the like, thereby forming the outermost layer in the lens. The light beam that travels is allowed to escape to the outside by irregular reflection on the rough surface, and external light incident on the outer peripheral surface is irregularly reflected to suppress light transmission into the lens. Further, a black resin is used as an adhesive for bonding the lens elements. Even if these measures are taken, the black pigment in the adhesive that bonds the lens elements is not uniformly dispersed, and a locally transparent portion is formed between adjacent lens elements, or the above-mentioned when the lens array is assembled. Due to the high viscosity of the adhesive, the resin does not sufficiently conform to the irregularities on the outer peripheral surface of the lens, and a non-impregnated part is locally generated. As a result, light leakage occurs and sufficient optical performance cannot be obtained. There was a problem. In addition, since the rough outer surface of the lens is microscopically sharp and uneven, it tends to cause stress concentration and has relatively deep cracks apart from the average unevenness. However, there is a problem in that the strength of the lens array is weak and often breaks during assembly of the lens array.
[0005]
As a method of processing a synthetic resin lens, in JP-A-6-222218, etc., an optical transmission body in which an irregular portion of the refractive index distribution in the outer peripheral portion that causes flare light is deleted using a solvent or a cutter is deleted. A method has been proposed. Although the method of deleting in this way is a very effective method, there have been problems such as waste disposal after the deletion, solvent recovery, and the cutting blade has a very short life.
[0006]
Further, in JP-A-7-120604 and JP-A-7-146436, after removing an irregular portion of the refractive index distribution at the outer peripheral part that causes flare light using a solvent or a knife, the solvent absorbs light. There has been proposed a technique in which a light absorber is immersed in a solution in which the agent is dissolved, the light absorber is diffused from the outside thereof, and the light absorber is introduced into the light transmitter. By using these methods, the optical properties of the optical transmission body are remarkably high. However, as described above, the processing of waste after removal, the recovery of the solvent, the cutting blade has a very short life, etc. There was a problem.
[0007]
JP-A-1-105202 proposes an optical transmitter, an optical transmitter array, and a method of manufacturing the same, in which a light absorber is present in the composition constituting the optical transmitter at the outer periphery of the optical transmitter. Has been.
[0008]
[Problems to be solved by the invention]
However, since the present invention is manufactured by a method in which the light absorber dissolved in the solvent is absorbed from the outer periphery of the optical transmission body, the concentration distribution of the optical absorber is inevitable, and the light in the radial direction of the cross section of the optical transmission body is unavoidable. The concentration distribution of the absorbent is higher at the outer peripheral portion and lower at the center side.
[0009]
By the way, light traveling in a cylindrical optical transmission body (hereinafter referred to as “lens” where appropriate) whose refractive index continuously decreases from the center toward the outer peripheral portion is located at the position of the outer peripheral surface in the cross section of the lens. It is the smallest, and the more the position is closer to the center, the more it is. In addition, when the irregular portion of the refractive index distribution exists in a predetermined range of the outer peripheral portion of the lens, it is necessary to mix a light absorber over the entire irregular portion. However, in the light absorber concentration distribution according to this prior art method, since the concentration of the light absorber is lower toward the center side where the amount of light traveling is larger, it is difficult to efficiently remove flare light caused by this irregularity. . Then, if an attempt is made to impregnate a light absorber having a sufficient concentration at the innermost position (center side) of the irregular portion, the light absorber is impregnated even in a portion that is not an irregular portion on the central portion side. As a result, there arises a problem that the amount of light transmission is reduced.
[0010]
In addition, when these optical transmission bodies are used as a single lens, an adhesive is used to fix the lens to other members, and when an optical transmission body array is used, an adhesive is used to fix the lenses to each other and the lens and the substrate. An agent is used. However, when the light absorber is present up to the outer peripheral surface of the optical transmission body and the amount of the light absorber is increased as it goes to the outer peripheral portion side, the light absorber is bonded by the adhesive. Difficulties are likely to occur such as diffusion to the adhesive layer, reaction between the adhesive and the light absorber causing interaction, shifting of the light absorption peak of the light absorber, and inhibition of curing of the adhesive. is there.
[0011]
Furthermore, the method disclosed in Japanese Patent Application Laid-Open No. 1-105202 has a problem in that since the solvent is used, the solvent remains in the optical transmission body, and the lens performance changes with time due to the solvent. Another problem is that the outer dimensions of the optical transmission body change due to the solvent treatment and dimensional spots are likely to occur.
[0012]
Japanese Patent Application Laid-Open No. 6-51141 discloses a multifilament type optical fiber in which a colorant is added to the protective layer (outermost layer) of the optical fiber. However, the present invention is a technique for blocking the light entering the optical fiber from the outside, and the portion where the colorant is mixed is outside the optical transmission body and is a protective layer portion for preventing damage to the optical fiber. is there.
[0013]
Also, in this optical fiber manufacturing method, a thermoplastic resin is used as the outermost light blocking protective layer, but a plastic gradient index optical transmission manufactured by multilayer spinning of an uncured resin composition. It is virtually impossible to apply a technique of arranging a thermoplastic resin in the outermost layer to the body manufacturing technique.
[0014]
JP-A-4-251805 discloses a refractive index distribution type optical transmission body in which a plurality of spinning solutions having different dye concentrations are subjected to multilayer spinning. However, the present invention aims to make the light quantity distribution of the light emitted from the optical transmission body uniform, and the dye is present throughout the optical transmission body. That is, this prior art has a technical idea with the present invention having a structure in which a dye or the like is present only in an irregular portion of the refractive index distribution of the optical transmission body, and a dye or the like is not substantially present in the optical transmission section of the optical transmission body. It is completely different.
[0015]
In addition, since the photopolymerization method needs to transmit light for photopolymerization from the outer peripheral portion to the central portion, the concentration of the mixed light absorber must be extremely low.
That is, in these prior arts, an optical transmission body having good optical transmission characteristics of the optical transmission unit and less flare light has not been obtained, and an efficient manufacturing method of an optical transmission body that exhibits such performance is not available. Not obtained.
[0016]
An object of the present invention is to provide an optical transmission body, a high-resolution lens, and a lens array, in which the optical transmission section of the optical transmission section is good and flare light is small.
[0017]
Another object of the present invention is to provide a method for efficiently and easily mixing a light absorber or the like having a uniform concentration for suppressing flare light in the optical transmission body or the lens outer peripheral portion that exhibits the above performance.
[0018]
[Means for Solving the Problems]
The gist of the present invention is a cylindrical optical transmission body in which the refractive index continuously decreases from the center toward the outer periphery, Only in a predetermined range from 1 μm to 100 μm from the position of the outer peripheral surface toward the center Further, there is an optical transmission body in which a layer having a uniform concentration of light absorber or light scattering agent is formed.
[0019]
The gist of the present invention is The optical transmission body does not contain a light absorbing agent and a light scattering agent in a portion within 5 μm from the position of the outer peripheral surface toward the center. It is in.
[0020]
The gist of the present invention is a cylindrical optical transmission body in which the refractive index continuously decreases from the center toward the outer peripheral portion in the optical transmission body, and is within 100 μm from the position of the outer peripheral surface toward the central direction. In the optical transmission body, two or more layers having a uniform concentration of the light absorbing agent or the light scattering agent are formed in a predetermined range.
[0021]
Furthermore, the gist of the present invention is that the refractive index of the cured product obtained after curing is n. ₁ , N ₂ , ..., n _N (N is an integer greater than or equal to 3) N uncured materials are concentrically laminated to form a fiber-shaped uncured material laminate in which the refractive index decreases sequentially from the center to the outer periphery. , While performing the interdiffusion treatment of components between adjacent layers so that the refractive index distribution between each layer of this laminate continuously changes, or after performing the interdiffusion treatment, the laminate is cured, and the refractive index In the method for producing a distributed fiber, the laminate is formed in a state where a light absorber or a light scattering agent is mixed in at least one of N / 2 or more uncured layers from the center. It is in.
[0022]
Further, the gist of the present invention is directed to the center direction from the position of the outer peripheral surface of the optical transmission body after curing in the manufacturing method of the optical transmission body. 1μm or more It is to form a laminate in a state where a light absorber or a light scattering agent is mixed in at least one layer of an uncured material layer corresponding to a predetermined range within 100 μm.
[0023]
The gist of the present invention is to mix a light absorber or light scattering agent into at least the (N-1) th uncured material layer in any one of the above-mentioned methods for producing an optical transmission body.
[0024]
Further, the gist of the present invention is to mix a light absorber or light scattering agent into two or more adjacent uncured material layers in any of the above-mentioned methods for producing an optical transmission body.
[0025]
Further, the gist of the present invention is to perform a curing treatment by a photopolymerization method in the method for producing any one of the above optical transmitters, and the absorbance in a specific wavelength region of 400 to 750 nm is the absorbance at 300 to 370 nm. The purpose is to perform a curing treatment by a photopolymerization method using ultraviolet rays having an emission wavelength of 300 to 370 nm using a light absorber that is twice or more.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical transmission body and the manufacturing method thereof according to the present invention will be described in detail.
1 and 2 are a longitudinal sectional view and a transverse sectional view, respectively, of a gradient index lens which is an example of the optical transmission body of the present invention. 3 and 4 are a longitudinal sectional view and a transverse sectional view of the optical transmission body when the light absorbing agent or the light scattering agent is not present in the outermost peripheral portion. Each lens material 1 has a refractive index on the central axis 4 of N ₀ If the refractive index distribution constant is A, a transparent cylinder having a refractive index distribution in which the refractive index N (r) at a distance r in the radial direction from the central axis is approximately expressed by the relationship of the following equation. is there.
N (r) = N ₀ (1-Ar ² (1)
The optical transmission body of the present invention is characterized in that a light absorbing agent or a light scattering agent is mixed almost uniformly in a portion where the refractive index of the outer peripheral portion is irregular. Since the light absorbing agent or the light scattering agent is dispersed in the outer peripheral portion, flare light generated in the vicinity thereof is completely absorbed by the light absorbing agent without being reflected at the interface, or is scattered by the light scattering agent. That is, since the light absorber or the light scattering agent is uniformly present in the thickness direction in the composition constituting the optical transmission body, the flare light is more effectively absorbed inside the lens by the light absorber, or the light It is scattered inside the lens by the scattering agent.
[0027]
In the cylindrical light transmission body of the present invention, the light absorber or the light scattering agent is mixed in a predetermined range within 100 μm from the position of the outer peripheral surface. The thickness of the layer in which the light absorber or light scattering agent exists (hereinafter referred to as “light shielding layer” as appropriate) is appropriately determined depending on the width of the irregular portion of the refractive index distribution, the concentration of the light absorber or the light scattering agent, and the like. However, it is usually about 5 to 70 μm.
[0028]
The thickness of the light shielding layer may be the whole or a part of the irregular portion of the refractive index distribution. However, in the latter case, it is necessary to mix a light absorber or the like in a concentration that can sufficiently absorb or scatter flare light by using a portion including the innermost irregular portion as a light shielding layer. Furthermore, considering the effect of preventing crosstalk, it is preferable to determine the concentration of the light absorber and the like in the light shielding layer and the thickness of the light shielding layer for the purpose of preventing the incidence of light from the outside of the optical transmission body.
[0029]
That is, the light shielding layer can be formed between 1) a predetermined position of 100 μm or less from the outer peripheral surface toward the center to the outer surface, and 2) a predetermined 2 of 100 μm or less from the outer surface to the center. Can be formed between two positions. Specifically, the light shielding layer can be present in a predetermined range of a position within a range of 1 μm to 100 μm from the position of the outer peripheral surface toward the center.
[0030]
The light shielding layer may be divided into two or more layers and the concentration in each layer may be changed. For example, in the case of aiming to prevent the incidence of light from the outside of the optical transmission body, the light shielding layer can be two or more layers, and the concentration in the outer light shielding layer can be increased.
[0031]
Specifically, for example, only the Nth layer (outermost layer), only the N-1th layer, two layers of the Nth layer and the N-1th layer, the N-1th layer and the N-2th layer The two layers, the Nth layer, the N−1th layer, and the N−2th layer can be used as a light shielding layer. In addition, when the light absorber of the same density | concentration is mix | blended with two adjacent layers at the time of manufacture, the light shielding layer is regarded as one layer in the obtained optical transmission body.
[0032]
As the light absorber in the present invention, various dyes, pigments and pigments suitable for the emission wavelength of the optical system in which the optical transmission body is used can be used. For the purpose of absorbing all the light in the visible light region, a black one in which various dyes, pigments and pigments are mixed can be selected. Of course, light absorbers such as carbon black and graphite carbon can also be used. Other materials that absorb light are not particularly limited. In the present invention, it is preferable that the light absorber is present dispersed in the composition constituting the optical transmission body. In this state, dye molecules and pigment molecules are dispersed or bonded in an organic polymer body in a physical or chemical affinity field.
[0033]
The concentration of the light absorber contained in the uncured product is 0.01 to 10% by weight, preferably 0.01 to 1% by weight. If the concentration is too low, there is no effect of preventing flare light.
[0034]
In the present invention, as the light scattering agent, resin fine particles such as nylon, polystyrene, polyethylene, polyester and silicone resin, inorganic fine particles such as titanium oxide, silica and alumina, calcium carbonate, cellulose, clay, wheat flour, water-soluble starch and the like Fine powder. In addition, fine powders that are insoluble in the monomer that is the raw material of the optical transmission body can be used. In the present invention, it is desirable that the light scattering agent is uniformly dispersed in order to increase the effect of adding the light scattering agent. From these points, it is preferable that the fine powder (light scattering agent) has a small particle size and a uniform particle size.
[0035]
The concentration of the light scattering agent contained in the uncured product is in the range of 0.2 to 10% by weight, preferably 0.25 to 5% by weight. If the concentration is too low, there is no effect of preventing flare light.
[0036]
The optical transmission body of the present invention can be manufactured, for example, as follows.
The refractive index of the cured product obtained after curing is n ₁ , N ₂ , ..., n _N A light absorber or a light scattering agent is mixed in at least one of N / 2 or more uncured material layers from the center among N uncured materials that are (N is an integer of 3 or more), These uncured materials are arranged so that the refractive index gradually decreases from the center toward the outer peripheral surface, and are a stack of uncured materials that are concentrically laminated (hereinafter referred to as “threads” as appropriate). ) And curing the filamentous material while performing the interdiffusion treatment of the material between adjacent layers so that the refractive index distribution between each layer of the filamentous material becomes a continuous distribution or after the mutual diffusion treatment. It is manufactured by.
[0037]
Further, in a state where a light absorber or light scattering agent is mixed in at least one layer of the uncured material layer corresponding to a predetermined range within 100 μm from the position of the outer peripheral surface of the optical transmission body after curing toward the center direction. It can also be shaped into a filament.
[0038]
In order to make the refractive index distribution of the obtained optical transmission body close to an ideal distribution, N is preferably at least 4 or more. In consideration of ease of production, N is preferably about 6 or less. However, N can be increased to 10 or more in order to obtain a high-performance optical transmission body. The thicknesses of the layers may be different or the same.
[0039]
The uncured material used in the present invention has a viscosity of 10 ^Three -10 ⁸ It is preferably poise and curable. If the viscosity is too small, thread breakage occurs during shaping, and it is difficult to form a thread. On the other hand, if the viscosity is too large, the operability is poor at the time of shaping, and the concentricity of each layer is impaired, or a filamentous body having a large thickness is liable to be formed.
[0040]
As a substance constituting the uncured material, a radical polymerizable vinyl monomer or a composition comprising the monomer and a polymer soluble in the monomer can be used.
[0041]
Specific examples of the radical polymerizable vinyl monomer include methyl methacrylate (n = 1.49), styrene (n = 1.59), chlorostyrene (n = 1.61), vinyl acetate (n = 1.47). 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,3,3,4,4,5,5-octafluoropentyl (meth) acrylate, 2,2,3,4,4 1,4-hexafluorobutyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, etc., fluorinated alkyl (meth) acrylate (n = 1.37 to 1.44), refractive index 43-1.62 (meth) acrylates such as ethyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, hydroxyalkyl (meth) acrylate, alkylene glycol (meth) acrylate, trimethyl Dipropane glycol di or tri (meth) acrylate, pentaerythritol di, tri or tetra (meth) acrylate, diglycerin tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and other diethylene glycol bisallyl carbonate, fluorinated alkylene glycol Examples thereof include poly (meth) acrylate.
[0042]
In order to easily adjust the viscosity of the uncured material when forming the filament from these uncured materials, and to have a continuous refractive index distribution from the center to the outer periphery of the filament, The material is preferably composed of a vinyl monomer and a soluble polymer.
[0043]
The polymer that can be used here needs to have good compatibility with the polymer produced from the radical polymerizable vinyl monomer, for example, polymethyl methacrylate (n = 1.49), polymethyl methacrylate copolymer ( n = 1.47-1.50), poly-4-methylpentene-1 (n = 1.46), ethylene / vinyl acetate copolymer (n = 1.46-1.50), polycarbonate (n = 1) .50 to 1.57), polyvinylidene fluoride (n = 1.42), vinylidene fluoride / tetrafluoroethylene copolymer (n = 1.42 to 1.46), vinylidene fluoride / tetrafluoroethylene / hexa Examples thereof include a fluoropropene copolymer (n = 1.40 to 1.46) and a polyfluorinated alkyl (meth) acrylate polymer.
[0044]
In order to adjust the viscosity, it is preferable to use a polymer having the same refractive index in each layer because a plastic optical transmission body having a continuous refractive index distribution from the center toward the outer periphery can be obtained. In particular, polymethylmethacrylate is excellent in transparency and has a high refractive index, so that it is suitable as a polymer for use in preparing the gradient index optical transmission body of the present invention.
[0045]
In order to cure the filament formed from the uncured material, it is preferable to add a thermosetting catalyst or a photocuring catalyst to the uncured material. As the thermosetting catalyst, a peroxide-based or azo-based catalyst is usually used. Photocuring catalysts include benzophenone, benzoin alkyl ether, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, benzyl methyl ketal, 2,2-diethoxyacetophenone, chlorothioxanthone, thioxanthone compounds, benzophenone Examples thereof include ethyl compounds, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, N-methyldiethanolamine, and triethylamine.
[0046]
Next, in order to cure the uncured product, ultraviolet rays are preferably applied from the surroundings in the cured part, and the filament containing the thermosetting catalyst and / or the photocuring catalyst is subjected to heat treatment or photocuring treatment.
[0047]
In the production method of the present invention, the magnitude relationship between the molecular weight of the light absorber and the monomer is not particularly limited, but a mixture of the monomer and the polymer is used as an uncured product, and the dye or the like is used as the light absorber. Is used, the light absorber has a much higher molecular weight than the monomer, so the diffusion rate in the uncured product is much slower. Accordingly, the monomer can be diffused between the uncured material layers without substantially diffusing the light absorber.
[0048]
In the case of thermal polymerization that requires a long time for polymerization and curing, the light absorber diffuses, the concentration in the light shielding layer becomes non-uniform, and the dye or the like moves to a portion where the refractive index distribution is normal. There is a possibility that the light transmission function of the optical transmission body may be impaired. For this reason, it is desirable to cure by photopolymerization capable of polymerization in a short time.
[0049]
By the way, in order to polymerize and cure by the photopolymerization method, it is necessary to transmit light for photopolymerization through the uncured material layer. However, there are many types of light absorbers, and the wavelength dependency of light absorption varies. That is, there exists a light absorber that absorbs the transmission light of the optical transmission body and absorbs the light for polymerization at the same level or higher. Therefore, in the case of polymerizing and curing by the photopolymerization method, it is desirable to use a light absorber that absorbs the transmitted light of the optical transmission body but has a property of transmitting the polymerization light without absorbing it.
[0050]
The light actually used as the transmission light of the optical transmission body is usually in the range of visible light to near infrared light having a wavelength of 400 to 750 nm. On the other hand, the emission wavelength of light used for photopolymerization is usually 300 to 370 nm. Therefore, it is preferable to use a light absorber having an absorbance in a specific wavelength region of 400 to 750 nm that is twice or more of an absorbance at 300 to 370 nm.
[0051]
Typical examples of such a light absorber include the following. As a cover for 740 nm, which is the emission wavelength of LED light for LED printers, Kayasorb CY-10 manufactured by Nippon Kayaku Co., Ltd., which absorbs at 700 nm or more can be mentioned. Further, as a cover for the light emission wavelength of the LED of an image scanner such as a facsimile, 570 nm, Nippon Kayaku Kayset Blue ACR which absorbs at 550 to 670 nm, and equivalents of other companies in the same industry can be mentioned. As light absorbers effective for other wavelength regions, those having absorption at 400 to 500 nm include Nippon Kayaku Kaysorb Yellow 2G, Orange G, Yellow AG, Yellow EG, and their respective businesses. Other company's equivalents, Mitsui Toatsu Dye's MS Yellow HD-180 and its competitors' equivalents. Examples of those having absorption at 500 to 600 nm include Kaysorb Red G, Red 130, Red B, and equivalents of the same industry, and Mitsui Toatsu Dye MS Magenta HM-1450 and equivalents thereof. These dyes can be used alone or in combination.
[0052]
8 and 9 are diagrams showing absorption spectra of CY-10 and Blue ACR, which are typical dyes used in the present invention, where the horizontal axis is wavelength (nm) and the vertical axis is an ultraviolet-visible spectrum measuring apparatus. This is a current value (ampere) actually measured by the sensor, and this current value is proportional to the absorbance. It can be seen that there is little absorption in the ultraviolet region (300 to 370 nm), and the absorbance there is less than or equal to ½ of the absorbance at each wavelength in the actual use wavelength range of 740 nm or 570 nm. When such a light absorber is used, ultraviolet rays are transmitted through the uncured material layer, and photopolymerization proceeds efficiently.
[0053]
The optical transmission body of the present invention can be manufactured, for example, using the filamentous body forming apparatus of FIG. FIG. 5 is a process diagram schematically showing the thread-like body forming apparatus, in which only the portions of the mutual diffusion portion 12 and the curing processing portion 13 are shown in a longitudinal sectional view. In the figure, symbol 10 is a concentric composite nozzle, 11 is an uncured extruded filament, 12 is an interdiffusion section for diffusing the monomers of each layer of the filament to give a refractive index distribution, 13 Is a curing processing unit for curing the uncured material, 14 is a take-up roller, 15 is a manufactured light transmission body, 16 is a winding unit, 17 is an inert gas inlet, and 18 is an inert gas outlet. is there. In order to remove the volatile substance released from the filament 11 from the interdiffusion unit 12 and the curing processing unit 13, an inert gas such as nitrogen gas is introduced from the inert gas inlet 17.
[0054]
Examples of the light source used for photopolymerization include a carbon arc lamp that generates light having a wavelength of 150 to 600 nm, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a chemical lamp, a xenon lamp, and a laser beam.
[0055]
【Example】
The present invention will be specifically described below with reference to examples. In Examples and Comparative Examples, refractive index distribution and lens performance (MTF) were measured by the following methods.
[0056]
(1) Refractive index distribution measurement
Measurement was performed by a known method using an Interfaco interference microscope manufactured by Carl Zeiss.
[0057]
(2) Measurement of lens performance (MTF)
The MTF indicating the resolution of the optical transmission body is a grating having a spatial frequency of 4 (line pairs / mm, Lp / mm), a single lens whose both end surfaces perpendicular to the optical axis are polished, or optical transmission as shown in FIG. An array in which a plurality of bodies are arranged and a light source are arranged as shown in FIG. 6, and a lattice image is read by a CCD line sensor installed on the imaging plane, and the maximum value (i _MAX ) And minimum value (i _MIN ) Was measured as shown in FIG.
[0058]
MTF (%) = (i _MAX -I _MIN ) / (I _MAX + I _MIN ) × 100 (2) Here, as shown in the grid of FIG. 6, the spatial frequency is a combination of white lines and black lines, and the number of combinations of these lines within a width of 1 mm. It shows whether it is provided.
[0059]
Comparative Example 1
50 parts by weight of polymethyl methacrylate ([η] = 0.40, measured at 25 ° C. in MEK), 36 parts by weight of benzyl methacrylate, 14 parts by weight of methyl methacrylate, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone and hydroquinone 0.1 parts by weight was heated and kneaded at 70 ° C. to obtain a stock solution for forming the first layer. 51 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 49 parts by weight of methyl methacrylate, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone, 0.1 part by weight of hydroquinone The mixture was heated and kneaded at 70 ° C. to obtain a second layer forming stock solution. 48 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 37 parts by weight of methyl methacrylate, 2,2,3,3,4,4,5,5-octafluoropentyl 15 parts by weight of methacrylate, 0.25 parts by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 parts by weight of hydroquinone were heated and kneaded at 70 ° C. to obtain a third layer forming stock solution. 45 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 25 parts by weight of methyl methacrylate, 2,2,3,3,4,4,5,5-octafluoropentyl 30 parts by weight of methacrylate, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 part by weight of hydroquinone were heated and kneaded at 70 ° C. to obtain a fourth layer forming stock solution. 42 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 15 parts by weight of methyl methacrylate, 2,2,3,3,4,4,5,5-octafluoropentyl 43 parts by weight of methacrylate, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 part by weight of hydroquinone were heated and kneaded at 70 ° C. to obtain a fifth layer forming stock solution. These five types of undiluted solutions were arrayed sequentially from the center using a concentric five-layer composite nozzle so that the refractive index of the uncured product was lowered and extruded simultaneously.
[0060]
The temperature of the composite spinning nozzle was 55 ° C. The viscosity at the time of extrusion is 4.5 x 10 for the first layer component ^Four Poise, second layer is 3.8 × 10 ^Four Poise, third layer is 3.5 × 10 ^Four Poise, 4th layer is 2.9 × 10 ^Four Poise, 5th layer is 3.2 × 10 ^Four It was a poise. The ejection ratio from the first layer to the fifth layer was 35/38/20/6/1 in terms of radius.
Then, the strand fiber was passed through the center of the light irradiation section disposed at equal intervals in a circular manner at 12 chemical lamps of 120 cm in length and 40 W in length through each layer interdiffusion treatment section of 55 cm in length, and 70 cm / min. It was taken up with a nip roller at a speed of.
[0061]
The obtained optical transmission body has a radius (r ₀ ) Was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. Both ends of this optical transmission body were polished to a lens length of 6.6 mm, and the characteristics of this single lens were measured using a 4 Lp / mm grating. The conjugate length with respect to light having a wavelength of 570 nm was 14.4 mm. The MTF at the conjugate length was 65%. The conjugate length with respect to the wavelength of 740 nm was 15.4 mm, and the MTF at the conjugate length was 61%.
[0062]
Furthermore, using this optical transmission body, two phenolic resins (thickness 1.2 mm) are used for the side plates, and an epiform (manufactured by Somar) to which 2 wt% of carbon black is added is used as the adhesive. The optical transmitters were arranged in a row and filled with an adhesive, the adhesive was cured, and then both end surfaces were cut and polished to produce a lens array with a lens length of 6.6 mm. When the characteristics of this lens array were measured using a 4 Lp / mm grating, the conjugate length with respect to light having a wavelength of 570 nm was 14.4 mm, and the MTF at the conjugate length was 63%.
[0063]
Using this optical transmitter array, an image scanner having an LED having a light emission wavelength of 570 nm as a light source and a CCD as a light receiving element was assembled. This image scanner has a slightly low resolution due to the influence of flare light, and it is difficult to transmit an image clearly.
[0064]
Comparative Example 2
The optical transmission member prepared in Comparative Example 1 was immersed in chloroform at a temperature of 35 ° C. for 1 minute to swell. Next, the optical transmission body was forcibly passed through a hole in a silicone rubber having a hole having a radius of 0.25 mm. A portion having a depth of 35 μm in the radial direction was deleted from the outer peripheral portion of the optical transmission body.
[0065]
The obtained optical transmission body had a radius (r0) of 0.435 mm, and the refractive index distribution was 1.512 at the center and 1.470 at the outer periphery.
Using this optical transmission body, single lenses and lens arrays were manufactured in the same manner as in Comparative Example 1, and single lens characteristics and lens array characteristics were evaluated, and the results shown in Table 1 were obtained.
[0066]
When this optical transmitter array was left in a hot air dryer set at 70 ° C. for 24 hours, a change in lens characteristics occurred. When the lens characteristics were measured, the MTF was reduced by about 10% and the conjugate length was increased by about 1 mm. This was presumed to be due to the diffusion of chloroform remaining in the lens.
[0067]
Comparative Example 3
The optical transmission body prepared in Comparative Example 1 was immersed in a chloroform solution in which 0.5 wt% of dye varifast black manufactured by Orient Chemical Co., Ltd. was dissolved for 1 minute at a temperature of 25 ° C. and then 3 minutes in a drying furnace at 70 ° C. Processed. It was confirmed that the outer periphery of the optical transmission body was stained more densely in the range of 35 μm.
[0068]
Using this optical transmission body, single lenses and lens arrays were manufactured in the same manner as in Comparative Example 1, and single lens characteristics and lens array characteristics were evaluated, and the results shown in Table 1 were obtained.
The MTF of the lens array was considerably lower than that expected from the performance of a single lens. When the density | concentration of the dye in a lens array was confirmed, it has confirmed that the dye which existed in the optical transmission body outer peripheral part was spread | diffused in the adhesive bond layer, and has come out from the optical transmission body.
[0069]
Example 1
The stock solution of the first layer to the fifth layer is the same as that of Comparative Example 1, and 0.04 wt% of infrared absorbing dye CY-10 manufactured by Nippon Kayaku Co., Ltd. is further added to the stock solution of the fourth layer. In the same manner as in No. 1, the mixture was heated and kneaded at 70 ° C. to obtain a fourth layer stock solution. The viscosity at the time of spinning was the same as in Comparative Example 1. An optical transmission body was obtained in the same manner as in Comparative Example 1 with respect to the discharge ratio at the time of composite spinning, the passage conditions of each layer interdiffusion treatment section, the light irradiation conditions, and the nip roller take-up conditions. Incidentally, CY-10 used in this example does not absorb ultraviolet rays.
[0070]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A portion of 5 μm from the outer peripheral portion of the optical transmission body was an undyed layer, and a dyed layer of 28 μm was formed on the inside thereof, and the dye concentration was almost uniform.
[0071]
When the lens length was 6.6 mm and the lens characteristics were measured in the same manner as in Comparative Example 1 using light having a wavelength of 570 nm, the conjugate length was 14.4 mm and the MTF in the conjugate length was 65%. On the other hand, for a 740 nm light source, the conjugate length was 15.4 mm and the MTF at the conjugate length was 77%, which was higher than that of Comparative Example 1. It was confirmed that the resolving power of the lens is improved for LED light having an emission wavelength in the absorption wavelength region of the dye.
[0072]
Using this optical transmission body, two phenolic resins (thickness 1.2 mm) are used for the side plates, and epiform (made by Somar) with 2 wt% carbon black added to the adhesive, and light is transmitted between the side plates. The bodies were arranged in one row, filled with adhesive, and the adhesive was cured, and then both end faces were cut and polished to produce an array with a lens length of 6.6 mm. The conjugate length of this array with respect to light having a wavelength of 570 nm was 14.4 mm, and the MTF at the conjugate length was 63%. Further, the conjugate length with respect to light having a wavelength of 740 nm was 15.4 mm, and the MTF at the conjugate length was 75%. This MTF was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed.
[0073]
Example 2
In Example 1, as a dye added to the fourth layer, Nippon Kayaku Co., Ltd. dye Blue ACR (0.02 wt%) was used instead of CY-10, and the ultraviolet irradiation amount was 1.1 times. Other conditions were the same as in Example 1 to obtain an optical transmission body. The Blue ACR used in this example has absorption in the ultraviolet region, so the amount of ultraviolet light is 1.1 times to adjust the amount of transmitted light.
[0074]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A portion of 5 μm from the outer peripheral portion of the optical transmission body was an undyed layer, and a dyed layer of 28 μm was formed on the inside thereof, and the dye concentration was almost uniform.
[0075]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed.
[0076]
Using this optical transmitter array, an image scanner having an LED having a light emission wavelength of 570 nm as a light source and a CCD as a light receiving element was assembled. This image scanner was hardly affected by flare light and had high resolution and could transmit images clearly.
[0077]
Example 3
In Example 1, the dye added to the stock solution of the fourth layer is Blue ACR (0.03 wt%) and CY-10 (0.03 wt%), and the amount of ultraviolet light in the light irradiation part is increased by 1.2 times. Except for the above, an optical transmission body was obtained in the same manner as in Example 1.
[0078]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A portion of 5 μm from the outer peripheral portion of the optical transmission body was an undyed layer, and a dyed layer of 28 μm was formed on the inside thereof, and the dye concentration was almost uniform.
[0079]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. In addition, the image scanner assembled and evaluated in the same manner as in Example 2 was hardly affected by flare light, and had high resolution and could transmit an image clearly.
[0080]
Example 4
The optical transmission medium was prepared in the same manner as in Comparative Example 1, except that the stock solutions of the first to fifth layers were the same as those in Comparative Example 1, and 0.04 wt% of CY-10 was further added to the stock solutions in the fourth and fifth layers. Got.
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A dyed layer of 35 μm was formed from the outer peripheral surface of the optical transmission body toward the center, and the dye concentration was almost uniform.
[0081]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained.
[0082]
Example 5
In Example 4, as a dye added to the fourth layer and the fifth layer, Blue ACR (0.02 wt%) was used instead of CY-10, and the ultraviolet irradiation amount was 1.1 times. The conditions were the same as in Example 4, and an optical transmission body was obtained in the same manner.
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A dyed layer of 35 μm was formed from the outer peripheral surface of the optical transmission body toward the center, and the dye concentration was almost uniform.
[0083]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. In addition, the image scanner assembled and evaluated in the same manner as in Example 2 was hardly affected by flare light, and had high resolution and could transmit an image clearly.
[0084]
Example 6
In Example 4, the dyes added to the stock solutions of the fourth layer and the fifth layer are Blue ACR (0.03 wt%) and CY-10 (0.03 wt%), and the amount of ultraviolet light in the light irradiation unit is 1.2. The optical transmission body was obtained in the same manner as in Example 4 except for the above.
[0085]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A dyed layer of 35 μm was formed from the outer periphery of the optical transmission body, and the dye concentration was almost uniform.
[0086]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array is assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. Further, the image scanner assembled and evaluated in the same manner as in Example 2 had almost no influence by flare light, and had high resolution and could transmit an image clearly.
[0087]
Example 7
52 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 32 parts by weight of benzyl methacrylate, 16 parts by weight of methyl methacrylate, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone and hydroquinone 0.1 parts by weight was heated and kneaded at 70 ° C. to obtain a stock solution for forming the first layer. 51 parts by weight of polymethyl methacrylate ([η] = 0.40, measured at 25 ° C. in MEK), 35 parts by weight of methyl methacrylate, 7 parts by weight of benzyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate 7 Part by weight, 0.25 part by weight of 1-hydroxycyclohexyl phenyl ketone and 0.1 part by weight of hydroquinone were heated and kneaded at 70 ° C. to obtain a stock solution for forming the second layer. 48 parts by weight of polymethyl methacrylate ([η] = 0.40, measured at 25 ° C. in MEK), 37 parts by weight of methyl methacrylate, 15 parts by weight of 2,2,3,3-tetrafluoropropyl methacrylate, 1-hydroxy 0.25 parts by weight of cyclohexyl phenyl ketone and 0.1 parts by weight of hydroquinone were heated and kneaded at 70 ° C. to obtain a third layer forming stock solution.
[0088]
43 parts by weight of polymethyl methacrylate ([η] = 0.40, measured in MEK at 25 ° C.), 20 parts by weight of methyl methacrylate, 37 parts by weight of 2,2,3,3-tetrafluoropropyl methacrylate, 1-hydroxy 0.25 parts by weight of cyclohexyl phenyl ketone, 0.1 parts by weight of hydroquinone, and 0.05 parts by weight of Blue ACR were heated and kneaded at 70 ° C. to obtain a fourth layer forming stock solution.
These four types of undiluted solutions were sequentially arranged from the center so that the refractive index of the uncured product was lowered using a concentric four-layer composite nozzle and extruded simultaneously.
The temperature of the composite spinning nozzle was 50 ° C. The viscosity at the time of extrusion is 5.7 × 10 for the first layer component ^Four Poise, second layer is 3.9 × 10 ^Four Poise, third layer is 3.2 × 10 ^Four Poise, 4th layer is 3.3 × 10 ^Four It was a poise. The ejection ratio from the first layer to the fourth layer was 37/36/21/8 as a ratio of radii.
Then, the strand fiber was passed through the center of the light irradiation section disposed at equal intervals in a circular manner at 12 chemical lamps of 120 cm in length and 40 W in length through each layer interdiffusion treatment section of 55 cm in length, and 60 cm / min. It was taken up with a nip roller at a speed of.
[0089]
The obtained optical transmission body has a radius (r ₀ ) Was 0.45 mm, and the refractive index distribution was 1.510 at the center and 1.470 at the outer periphery. A dyed layer of 36 μm was formed from the outer peripheral surface of the optical transmission body toward the center, and the dye concentration was almost uniform. Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. Further, the image scanner assembled and evaluated in the same manner as in Example 2 had almost no influence by flare light, and had high resolution and could transmit an image clearly.
[0090]
Example 8
This example relates to a composite spinning of 6 layers, and dyes were mixed in the fourth layer and the fifth layer. The first layer, the second layer, the third layer, the fourth layer, the fifth layer, and the sixth layer undiluted solutions are the first layer, the second layer, the third layer, the third layer, the fourth layer, and the fourth layer of Comparative Example 1, respectively. It was the same as the fifth layer, and Blue ACR (0.03 wt%) and CY-10 (0.03 wt%) were added to the stock solutions of the fourth layer and the fifth layer. The discharge radius ratio of each layer in the composite spinning was 35/38/15/5/6/1, and the amount of ultraviolet light was 1.3 times. Otherwise, an optical transmission member was obtained in the same manner as in Example 4.
[0091]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A dye layer of 60 μm was formed from the outer periphery of the optical transmission body, and the dye concentration was almost uniform.
[0092]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. Further, the image scanner assembled and evaluated in the same manner as in Example 2 had almost no influence by flare light, and had high resolution and could transmit an image clearly.
[0093]
Example 9
The first to fifth layer stock solutions were the same as in Comparative Example 1, and CY-10 was 0.04 wt%, Blue ACR was 0.14 wt%, and Mitsui Toatsu Dye MS was used in the fourth layer stock solution. Yellow HD-180 0.10 wt% and Mitsui Toatsu dye MS Magenta HM-1450 0.08 wt% were added, and the mixture was heated and kneaded at 70 ° C. in the same manner as in Comparative Example 1.
[0094]
The viscosity at the time of spinning was the same as in Comparative Example 1. An optical transmission body was obtained in the same manner as in Comparative Example 1 with respect to the discharge ratio at the time of composite spinning, the passage conditions of each layer interdiffusion treatment section, and the nip roller take-up conditions. The CY-10 used in this example does not absorb ultraviolet light, and the Blue ACR, HD-180, and HM-1450 also absorb ultraviolet light, so the amount of ultraviolet light is 1.5 times that of Comparative Example 1. Polymerization was performed.
[0095]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A portion of 5 μm from the outer peripheral portion of the optical transmission body was an undyed layer, and a dyed layer of 28 μm was formed on the inside thereof, and the dye concentration was almost uniform.
[0096]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. This single lens was confirmed to have improved MTF in the entire visible light wavelength range. It was confirmed that the combination of these dyes improves the resolving power of the lens with respect to light in the entire visible light wavelength range. The MTF of the lens array is assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed.
[0097]
Using this optical transmitter array, an image scanner having an LED having a light emission wavelength of 570 nm as a light source and a CCD as a light receiving element was assembled. This image scanner was hardly affected by flare light and had high resolution and could transmit images clearly. Similarly, when an image scanner is assembled using a blue light source having a wavelength near 450 nm, or when an image scanner is assembled using a red light source having a wavelength near 611 nm, the resolution is hardly affected by flare light. The image could be transmitted clearly.
[0098]
Example 10
In Example 1, 0.04 wt% of CY-10, 0.14 wt% of Blue ACR, 0.08 wt% of MS Yellow HD-180, and MS Magenta HM- 0.08 wt% of 1450 is added, and the dye added to the stock solution of the fifth layer is 0.02 wt% of CY-10, 0.60 wt% of Blue ACR, 0.18 wt% of MS Yellow HD-180, In addition, 0.20 wt% of MS Magenta HM-1450 was added, and the mixture was heated and kneaded at 70 ° C. in the same manner as in Comparative Example 1.
[0099]
The viscosity at the time of spinning was almost the same as the stock solution before adding the dye. Further, an optical transmission body was obtained in the same manner as in Example 1 except that the amount of ultraviolet light in the light irradiation part was 1.4 times.
[0100]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. The part 5 μm from the outer periphery of the optical transmission body is a layer in which Blue ACR, HD-180, and HM-1450 are present in a high concentration, and 28 μm in which these dyes are present in a lower concentration than the outermost layer. A dyed layer was formed, and the dye concentrations in the two dyed layers were almost uniform.
[0101]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. This single lens was confirmed to have improved MTF in the entire visible light wavelength range. It was confirmed that the combination of these dyes improves the resolving power of the lens with respect to light in the entire visible light wavelength range. The MTF of the lens array is assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed.
[0102]
Further, as in Example 9, the image scanner assembled for each wavelength was hardly affected by flare light and had high resolution and could transmit an image clearly.
[0103]
Example 11
The stock solutions of the first layer to the fifth layer were the same as those in Comparative Example 1, and silica-based fine particles having an average particle size of 0.5 μm (Tospar 105 manufactured by Toray Silicone Co., Ltd.) were added to the 4-layer and 5-layer stock solutions. ) Was added at 0.5% by weight and heated and kneaded at 70 ° C. in the same manner as in Comparative Example 1 to obtain a stock solution of the fourth layer and the fifth layer. Compared to Comparative Example 1, the viscosity of the four-layer and five-layer stock solutions during spinning increased, and the fourth layer was 3.2 × 10. ^Four Poise, 5th layer is 4.0 × 10 ^Four It was a poise.
[0104]
The addition of the silica-based fine particles causes a slight shading of ultraviolet rays, so that the amount of ultraviolet rays was set to 1.05 times that of Comparative Example 1 in order to adjust the amount of transmitted light. The other conditions, that is, the discharge ratio at the time of composite spinning, the passing condition of each layer interdiffusion treatment section, the light irradiation condition, and the nip roller take-up condition were the same as in Comparative Example 1 to obtain an optical transmission body.
[0105]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A fine particle layer having a substantially uniform concentration was formed in a portion 35 μm from the outer periphery of the optical transmission body.
[0106]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. Further, the image scanner assembled and evaluated in the same manner as in Example 2 had almost no influence by flare light, and had high resolution and could transmit an image clearly.
[0107]
As described above, it was confirmed that by mixing the light scatterer in the outer peripheral portion of the optical transmission body, the optical performance can be improved to be equal to or higher than that in the comparative example 2 without the post-process as in the comparative example 2. In Comparative Example 2, it can be seen that the performance of the lens of this example is excellent considering that the lens performance is degraded by the residual solvent.
[0108]
Example 12
The stock solution of the first layer to the fifth layer is the same as that in Comparative Example 1, and 1.0 weight of polystyrene fine particles (SGP-70C manufactured by Soken Chemical Co., Ltd.) having a particle size of 5 to 30 μm is further added to the stock solution of the fourth layer. % And heated and kneaded at 70 ° C. in the same manner as in Comparative Example 1 to obtain a fourth layer stock solution. Compared with Comparative Example 1, the viscosity during spinning of the fourth layer undiluted solution increased to 4.1 × 10 ^Four It was a poise.
[0109]
The amount of ultraviolet light is 1.05 times that of Comparative Example 1, and the other conditions, that is, the discharge ratio at the time of composite spinning, the passing condition of each layer interdiffusion treatment unit, the light irradiation condition, and the nip roller take-up condition are Comparative Example 1. In the same manner, an optical transmission body was obtained.
[0110]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. The part 5 μm from the outer periphery of the optical transmission body is a layer in which fine particles do not exist, and a fine particle layer of 30 μm is formed on the inside thereof, and the concentration of the fine particles in the fine particle layer is almost uniform.
[0111]
Using this optical transmission body, a single lens and a lens array were manufactured in the same manner as in Example 1, the single lens characteristics and the lens array characteristics were evaluated, and the results shown in Table 1 were obtained. The optical performance of the optical transmission body was almost the same as that of Example 11 despite the absence of fine particles (light scattering agent) in the fifth layer portion. The MTF of the lens array was assumed from the performance of a single lens, and no diffusion of dye into the adhesive layer was observed. Further, the image scanner assembled and evaluated in the same manner as in Example 2 had almost no influence by flare light, and had high resolution and could transmit an image clearly.
[0112]
Example 13
The stock solution of the first layer to the fifth layer is the same as that of Comparative Example 1, and the polystyrene-based fine particles having an average particle diameter of 6 μm (Flobez LE-1080 manufactured by Sumitomo Seika Co., Ltd.) in the stock solution of the fifth layer. Was added in an amount of 2.0% by weight and heated and kneaded at 70 ° C. in the same manner as in Comparative Example 1 to obtain a stock solution of the fifth layer. Compared to Comparative Example 1, the viscosity of the fifth layer stock solution during spinning increased to 5.5 × 10. ^Four It was a poise.
[0113]
The amount of ultraviolet light is set to 1.02 times that of Comparative Example 1, and other conditions, that is, the discharge ratio at the time of composite spinning, the passing condition of each layer interdiffusion treatment unit, the light irradiation condition, and the nip roller take-up condition are Comparative Example 1. In the same manner, an optical transmission body was obtained.
[0114]
The radius of this optical transmission member was 0.47 mm, and the refractive index distribution was 1.512 at the center and 1.468 at the outer periphery. A fine particle layer having a substantially uniform concentration was formed at a portion of 5 μm from the outer periphery of the optical transmission body.
[0115]
The single lens characteristics and lens array characteristics were evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained. The optical performance of the optical transmission body was almost the same as that of Example 1 despite the absence of fine particles (light scattering agent) in the fourth layer.
[0116]
An image scanner was assembled in the same manner as in Example 1. Although this image scanner still had a slight influence due to flare light, the image scanner had higher resolution than that of Comparative Example 1 and was able to transmit an image clearly. It was confirmed that the MTF can be improved by mixing a light diffusing agent even in a small portion of the outer periphery of the optical transmission body.
[0117]
[Table 1]

[0118]
【The invention's effect】
The optical transmission body of the present invention can suppress flare light efficiently and easily because the light absorber or light scattering agent is present at a substantially uniform concentration in a portion where the refractive index distribution of the outer peripheral portion is irregular. High lens and lens array can be provided.
[0119]
Moreover, according to the manufacturing method of this invention, a light absorber or a light-scattering agent can be easily mixed in an optical transmission body. Further, since this manufacturing method does not use a solvent, the problem that the solvent remains in the optical transmission body and the lens performance changes with time does not occur.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an optical transmission body of the present invention.
2 is a cross-sectional view of the optical transmission body of FIG. 1. FIG.
FIG. 3 is a longitudinal sectional view of an optical transmission body according to another aspect of the present invention.
4 is a cross-sectional view of the optical transmission body of FIG. 3;
FIG. 5 is a schematic view of a manufacturing apparatus for manufacturing the optical transmission body of the present invention.
FIG. 6 is a diagram showing an outline of a resolution (MTF) measuring apparatus of an optical transmission body.
FIG. 7 is a diagram in which the resolution is measured by a CCD sensor.
FIG. 8 is a graph showing absorption characteristics of CY-10 used in the present invention.
FIG. 9 is a graph showing the absorption characteristics of Blue ACR used in the present invention.
[Explanation of symbols]
1 Lens material
2 Light absorber or light diffusing agent
3 Outermost peripheral part without light absorber or light diffusing agent
10 Concentric composite nozzle
11 Uncured filament
12 Interdiffusion section
13 Curing section
14 Pick-up roller
15 Optical transmitter
16 Winding part
17 Inert gas inlet
18 Inert gas outlet

Claims (4)

A cylindrical optical transmission body in which the refractive index continuously decreases from the center toward the outer peripheral portion, and is a light absorber only in a predetermined range from 1 μm to 100 μm from the position of the outer peripheral surface toward the center. Alternatively, an optical transmission body in which a layer having a uniform concentration of the light scattering agent is formed. The optical transmission body according to claim 1, wherein a light absorber and a light scattering agent are not contained in a portion within 5 μm from the position of the outer peripheral surface toward the center. _N uncured products having a refractive index of n ₁ , n ₂ ,..., _{N N} (N is an integer of 3 or more) are concentrically stacked to obtain a cured product obtained after curing. Forming a fiber-like uncured laminate with a refractive index that gradually decreases from the outer periphery to the outer periphery, and interdiffusion of components between adjacent layers so that the refractive index distribution between each layer of the laminate changes continuously In the method of manufacturing a gradient index fiber by curing the laminate while performing the treatment or after performing the mutual diffusion treatment, at least one of N / 2 or more uncured layers from the center portion the process according to claim 1 or 2 of the optical transmission body according to any one and forming a stacked body in a state of being mixed with light absorber or a light scattering agent in the layer. _N uncured products having a refractive index of n ₁ , n ₂ ,..., _{N N} (N is an integer of 3 or more) are concentrically stacked to obtain a cured product obtained after curing. Forming a fiber-like uncured laminate with a refractive index that gradually decreases from the outer periphery to the outer periphery, and interdiffusion of components between adjacent layers so that the refractive index distribution between each layer of the laminate changes continuously In the method of manufacturing a gradient index fiber having a radius R by performing a curing process on the laminated body after performing the treatment or after performing the interdiffusion process, the position of the outer peripheral surface of the optical transmission body after the curing is moved in the center direction. claim 1 or 2, characterized in that in a state in which at least one layer is mixed with light absorber or light scattering agent of uncured material layer corresponding to a predetermined range within 100μm or more 1μm towards forming a laminate Production of an optical transmission body according to any one of Method.

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