JP2007152724A - Molding method for resin, and manufacturing method for optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method for a resin which can make the thickness of a resin base extremely thin, and to provide a manufacturing method for a light-guiding path. <P>SOLUTION: This molding method for the resin has a process in which a pattern formed on a mold is transferred to the resin. As the resin 2, an anaerobic resin is used, and the resin is filled in the recess section of the mold 1 and pressed. The resin 2 is hardened under an atmosphere containing oxygen. Then, the molding method includes a process for removing a non-hardened section of the resin 2 by washing after the hardening of the resin 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin molding method and an optical element manufacturing method.

  In the method of using a mold to transfer the pattern formed on the mold to the resin to form the concavo-convex shape, the resin is usually sandwiched between the mold and the holding substrate, pressed and then cured, A method of peeling the cured resin from the mold has been adopted.

  In the resin molded product formed in this way, there is a need to make the resin (thickness of the resin base) other than the convex portions thin or no. For example, when nanoimprinting is performed, ashing must be performed by an amount corresponding to the resin thickness of the base layer of the molded resin layer, and if there is a variation in the value, the etching time in the subsequent process changes. The shape that is made will be uneven. Therefore, the resin base thickness is required to be as thin and uniform as possible, and if possible, close to none. In addition, even in a light guide path using resin (such as a method of guiding light by total reflection to a portion confined with a resin having a different refractive index), the presence of the resin base layer means that the light confinement becomes incomplete. There is a problem.

  However, in the conventional method, it is difficult to reduce the resin base thickness. Even if the resin viscosity before molding is considerably reduced, it is difficult to reduce the resin base thickness to several μm or less. Even if it can, even if it is limited, a wide area (a few inches in diameter) is uniformly several μm. It was not possible to:

  This invention is made | formed in view of such a situation, and makes it a subject to provide the molding method of the resin which can make resin base thickness very thin, and the manufacturing method of an optical element.

  A first means for solving the above problem is a resin molding method including a step of transferring a pattern formed on a mold to a resin, wherein an anaerobic resin is used as the resin, and the resin is formed in a concave portion of the mold. And a step of curing the resin in an atmosphere having an oxygen concentration of 20% or more, and then washing and removing uncured portions of the resin.

  In this means, the portion of the anaerobic resin that has entered the concave concave portion does not come into contact with oxygen and is cured, but the anaerobic resin remaining on the surface other than the concave portion is not cured under the influence of oxygen. Therefore, the resin base thickness can be made extremely thin or eliminated by washing away the uncured portion.

  The second means for solving the above-mentioned problem is the first means, and after cleaning and removing the uncured portion of the resin, the remaining surface of the resin is allowed to have an oxygen concentration of 5% or less. The method includes a step of curing in an atmosphere.

  In this means, even if there is a semi-cured portion between the uncured portion and the cured portion, the semi-cured portion can be cured and stabilized. The oxygen concentration is more preferably 1% or less.

  The third means for solving the above-mentioned problem is that an anaerobic resin is filled in the concave portion of the mold, the anaerobic resin is cured in an atmosphere containing oxygen, and then the uncured portion of the anaerobic resin is removed. Remove by washing, and then apply and cure another resin having a lower refractive index than the anaerobic resin on the surface of the anaerobic resin, and then integrate the anaerobic resin and the other resin, It is a manufacturing method of the optical element characterized by including the process of peeling from the said concave mold.

  In this means, since the resin base thickness of the anaerobic resin can be made extremely thin or eliminated, light is less likely to leak from the resin base thickness portion in the completed optical element, and the light confinement property is reduced. It becomes good.

  A fourth means for solving the above-mentioned problem is that an anaerobic resin is filled in the concave portion of the mold, and the anaerobic resin is cured in an atmosphere having an oxygen concentration of 20% or more. The uncured portion is removed by washing, and then another resin having a refractive index lower than that of the anaerobic resin is applied to the surface of the anaerobic resin, and the other resin is cured while being pressed with a reinforcing substrate. Then, the method includes the step of peeling the integrated anaerobic resin, the another resin, and the reinforcing substrate from the concave mold.

  Also in this means, since the resin base thickness of the anaerobic resin can be made extremely thin or eliminated, light is less likely to leak from the resin base thickness portion in the completed optical element, and the light confinement property is improved. It becomes good.

  The fifth means for solving the above-mentioned problem is the third means or the fourth means, and after cleaning and removing the uncured portion of the anaerobic resin, the fifth means is disposed on the anaerobic resin. The method further comprises a step of curing the remaining surface of the anaerobic resin in an atmosphere having an oxygen concentration of 5% or less before applying another resin having a lower refractive index than the anaerobic resin. is there.

  In this means, even if there is a semi-cured portion between the uncured portion and the cured portion, the semi-cured portion can be cured and stabilized. The oxygen concentration is more preferably 1% or less. A sixth means for solving the above problem is a method of manufacturing an optical element, wherein any one of the third to fifth means is a light guide.

  ADVANTAGE OF THE INVENTION According to this invention, the molding method of the resin which can make resin base thickness very thin, and the manufacturing method of an optical element can be provided.

Example 1
Hereinafter, a first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the quartz substrate was etched to create several concave grooves used for a waveguide (light guide), a length of 30 mm, and a cross-sectional shape of 80 μm square. A fluorine-based mold release agent was applied to the surface so that mold release was easy, and mold 1 was prepared (a).

  An ultraviolet curable resin 2 (anaerobic resin) was applied to the surface of the mold 1 with a spin coater. The conditions of the spin coater were set so that the pre-shaped recess was filled with resin, and the thickness of the portion corresponding to the base layer other than the recess was about 20 μm. Immediately after the spin coating, micro resin unevenness due to the uneven shape of the mold was generated, and therefore, it was left for a predetermined time after the spin coating was stopped. Although depending on the viscosity of the resin, the resin surface is made almost uniform by placing it for several minutes regardless of the unevenness (b).

  Next, this is irradiated with ultraviolet rays in the atmosphere or intentionally in an atmosphere with a high oxygen concentration (c). The ultraviolet curable resin 2 has anaerobic properties, and curing of the resin in the portion that is in contact with oxygen is inhibited. As a result, a portion of the ultraviolet curable resin 2 surrounded by the groove is cured, and a portion that is in contact with air (oxygen) is not cured. Under this condition, the uncured layer was approximately 20 μm.

  The thickness of the uncured layer varies depending on the curing characteristics inherent to the resin, the oxygen concentration during curing, and the amount of ultraviolet light. This time, the resin was applied so that the base layer thickness was 20 μm by adjusting the spin coating conditions. However, if the uncured layer thickness of the resin to be used is confirmed in advance by experiment, even if a different resin is cured, the base layer Can be set to be almost uncured.

  Thereafter, the uncured resin was removed by washing with a solvent (d). Thereafter, the surface of the remaining ultraviolet curable resin 2 was irradiated with ultraviolet rays in a nitrogen atmosphere to solidify the semi-cured portion of the interface (e). Depending on the resin, the cleaned surface may be rough and not smooth. In such a case, smoothing is possible by applying a very thin polymer having the same refractive index and then curing in a low oxygen atmosphere.

  Next, an ultraviolet curable resin 3 was applied to the surface, and a reinforcing substrate 4 through which ultraviolet rays were transmitted was placed and adhered thereto. The reinforcing substrate 4 has two actions of improving the resistance to bending and temperature change because the element itself is thin and the meaning of reinforcement when releasing from the mold after this. It may not be used depending on the application. Then, ultraviolet rays were irradiated through the reinforcing substrate 4 to cure the ultraviolet curable resin 3 (f). As a result, the ultraviolet curable resin 2, the ultraviolet curable resin 3, and the reinforcing substrate 4 are in close contact and integrated. Note that the refractive index n1 of the ultraviolet curable resin 2 is sufficiently larger than the refractive index n2 of the ultraviolet curable resin 3 for use as a waveguide.

  After that, when the mold 1 is peeled off, a plurality of rectangular columns 30 mm long and about 80 μm square formed by the UV curable resin 2 are formed on the UV curable resin 3 independently. (G).

The critical angle θ of total reflection of light at the resin layer interface is
sinθ = n2 / n1
Thus, by introducing light at a critical angle or less using an optical fiber into this square column cross section, it functions as a waveguide. In other words, the ultraviolet curable resin 2 and the ultraviolet curable resin 3 can be selected based on the necessary critical angle θ.

  Further, when the convex portion of the waveguide is exposed to the outside in use, the pattern is destroyed. In this case, the pattern surface of the completed waveguide can be covered with another resin. However, the refractive index n3 of this resin needs to be sufficiently smaller than n1 by an amount corresponding to the required critical angle. If this resin is the same as the ultraviolet curable resin 3, the waveguide of the ultraviolet curable resin 2 is completely wrapped like an optical fiber clad as an integrated resin.

Furthermore, in this example, the mold that is the basis of the pattern was created by etching a quartz substrate and the shape was made a quadrangular prism, but this method is not affected by the mold material and processing method, The mold may be manufactured by a method such as cutting or electroforming, and there is no problem even if the material of the mold is metal, semiconductor, resin or the like. Further, the cross section of the waveguide shape is not limited to a quadrangular prism but can be a polygonal shape to a curved surface. The waveguide pattern is not limited to a straight line, and can be curved, right-angled, branched, or the like as long as it is within the same plane. In addition, since the depth of the concave portion of the mold is variable, a multistage structure, an inclined structure, and the like are possible. Therefore, the method is applicable not only to the waveguide but also to various optical elements that allow light to pass in the direction perpendicular to the surface.
(Example 2)
A second embodiment of the present invention will be described below with reference to FIG. The quartz substrate was etched to form several continuous protrusions for use in the waveguide, a length of 30 mm, and a cross-sectional shape of 80 μm square. A fluorine mold release agent was applied on the surface so as to facilitate the mold release, and a mold was prepared (not shown).

  A resin concave plate 5 having a concave pattern having an inverted shape was formed by transfer from the mold using resin. Resin transfer enables mass production. The resin molding may be injection molding, but here, an ultraviolet curable resin was used and adhered to the reinforced glass (a).

  Subsequently, the ultraviolet curable resin 2 was applied to the surface of the resin concave plate 5 with a spin coater. The conditions of the spin coater were set so that the recesses were filled with resin in advance and the thickness of the portion corresponding to the base layer other than the recesses was about 20 μm. Immediately after the spin coating, micro resin unevenness due to the uneven shape was generated, so that the coating was left for a predetermined time after the spin coating was stopped. Although depending on the viscosity of the resin, the resin surface is made almost uniform by placing it for several minutes regardless of the unevenness (b).

  Subsequently, this was irradiated with ultraviolet rays in the atmosphere or in an atmosphere with a deliberately high oxygen concentration (c). The ultraviolet curable resin 2 has anaerobic properties, and curing of the resin in the portion that is in contact with oxygen is inhibited. As a result, the ultraviolet curable resin 2 is cured at the portion surrounded by the concave portion of the resin concave plate 5 and is not cured at the portion exposed to air (oxygen). Under this condition, the uncured layer was approximately 20 μm.

  The thickness of the uncured layer varies depending on the curing characteristics inherent to the resin, the oxygen concentration during curing, and the amount of ultraviolet light. This time, the resin was applied so that the base layer thickness was 20 μm by adjusting the spin coating conditions. However, if the uncured layer thickness of the resin to be used is confirmed in advance by experiment, even if a different resin is cured, the base layer Can be set to be almost uncured.

  Thereafter, the uncured resin was washed with a solvent to remove the uncured portion (d). Then, ultraviolet rays were irradiated in a nitrogen atmosphere with a low oxygen concentration to cure the interface (e).

  And the ultraviolet curable resin 3 was apply | coated to the surface by spin coating, and after the surface became flat, it was hardened by irradiating with ultraviolet rays (f). In this way, several square columns each having a length of 30 mm and a cross-sectional shape of about 80 μm square surrounded by the ultraviolet curable resin 3 and the resin concave plate 5 are formed independently. It was. Since the refractive index of the ultraviolet curable resin 3 and the refractive index of the resin constituting the resin concave plate 5 are sufficiently smaller than the refractive index of the ultraviolet curable resin 2, total reflection occurs at the interface. Acts as a waveguide.

It is a figure for demonstrating the 1st Example of this invention. It is a figure for demonstrating the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Type | mold, 2 ... Ultraviolet curable resin, 3 ... Ultraviolet curable resin, 4 ... Reinforcement board, 5 ... Resin concave plate,

Claims (6)

A resin molding method including a step of transferring a pattern formed on a mold to a resin, using an anaerobic resin as the resin, filling the concave portion of the mold with the resin, and in an atmosphere having an oxygen concentration of 20% or more And a step of curing the resin and then washing and removing uncured portions of the resin. The resin molding according to claim 1, further comprising a step of curing the remaining surface of the resin in an atmosphere having an oxygen concentration of 5% or less after removing the uncured portion of the resin by washing. Method. An anaerobic resin is filled in the concave portion of the mold, the anaerobic resin is cured in an atmosphere having an oxygen concentration of 20% or more, and then an uncured portion of the anaerobic resin is washed away and then the anaerobic resin is removed. Applying another resin having a refractive index lower than that of the anaerobic resin on the surface of the resin and curing the resin, and then removing the integrated anaerobic resin and the other resin from the concave mold. A method for manufacturing an optical element. The recess of the mold is filled with anaerobic resin, the anaerobic resin is cured in an atmosphere having an oxygen concentration of 20% or more, and then the uncured portion of the anaerobic resin is washed away and then the anaerobic resin is removed. An additional resin having a refractive index lower than that of the anaerobic resin is applied to the surface of the anionic resin, and the other resin is cured while being pressed with a reinforcing substrate, and then the integrated anaerobic resin, The method of manufacturing an optical element, comprising the step of peeling the resin and the reinforcing substrate from the concave mold. After washing and removing the uncured portion of the anaerobic resin, before applying another resin having a lower refractive index than the anaerobic resin on the anaerobic resin, the remaining surface of the anaerobic resin The method for producing an optical element according to claim 3, further comprising a step of curing in an atmosphere having an oxygen concentration of 5% or less. The optical element according to any one of claims 3 to 5, wherein the optical element is a light guide.

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