JPS6248971B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing optical members used in optical communication systems and various optical devices. More specifically, it has excellent wettability to optical components during work, and has excellent light transmittance, adhesive strength, and heat resistance after heating and curing.
The present invention relates to a method of manufacturing an optical member that can optimize and match the refractive index according to the refractive index of the optical member. [Prior Art] Conventionally, as a refractive index matching method, a method using silicone oil or the like has been known, and has been used, for example, for refractive index matching in the connection of optical fibers. However, since this type of refractive index matching agent is in liquid form, the process and operations are complicated, such as the need to seal the container to prevent its leakage, and long-term reliability cannot be fully guaranteed. Nakatsuta. This point will be explained based on FIGS. 1 and 2, taking as an example a method of matching the refractive index of optical fibers according to the prior art. That is, FIG. 1 is a schematic cross-sectional view of a conventional V-groove connection, and FIG. 2 is a perspective view thereof. In FIG. 1, reference number 1 indicates an optical fiber, 2 indicates a V-groove, 3 indicates an epoxy resin, 4 indicates matting oil, and 5 indicates an instant adhesive. In FIG. 2, the symbol 1 means the optical fiber, 6A to 6C the lid, and 7 the V-groove base. As shown in FIGS. 1 and 2, first, the optical fibers are brought together along the V-groove of the molded product, and silicone-based matting oil is dripped onto the mating area.
Temporarily attach the optical fiber to the molded product using an instant adhesive such as Aron Alpha. After that, adhesive is applied to the molded product and allowed to harden. This adhesive application and curing was intended to prevent matching oil from flowing out. However, this refractive index matching method has disadvantages in that the working process is complicated, the yield is poor, and long-term reliability cannot be fully guaranteed. Therefore, it has been desired to develop a refractive index matching method that can control the refractive index and prevent matching oil from flowing out. Further, when a laser diode is used as a light source, it is necessary to make the amount of return loss extremely small because noise is generated when reflected light enters the laser diode. This point will be explained based on FIG. FIG. 3 is a schematic diagram of laser light entering the optical fiber. In the figure, 1 is the same as in Figure 1,
11 is a glass fiber, 12 is a jacket, and 8 is a laser diode. As shown in FIG. 3, the entrance angle was slightly shifted from 0 degrees to prevent reflected light from returning to the laser diode light source even if the coupling was poor. For this reason, it has been desired to develop a refractive index matching method in which transmitted light cannot be maximized and reflection is extremely small. Furthermore, in order to solve these problems, a method of using an adhesive as a refractive index matching agent has been considered. However, conventional adhesives cannot change the refractive index, and for this reason, optical systems that use optical members that have a different refractive index from the adhesive, or optical members that have a wide range of refractive index distributions. However, when applied to a conventional device, the disadvantage is that transmission loss and reflection toward the input side become large. Furthermore, it is difficult for conventional adhesives to satisfy all of the requirements for wettability to optical components, light transmittance, adhesive strength, and heat resistance when applied to optical systems. It has been desired to develop a refractive index matching agent and a refractive index matching method using the same. [Object of the Invention] The present invention relates to a refractive index matching method using a refractive index matching agent that maintains fluidity during operation and solidifies after curing and does not flow out. An object of the present invention is to provide a method for manufacturing an optical member with excellent workability and long-term reliability. [Structure of the Invention] To summarize the present invention, the present invention is an invention of a method for manufacturing an optical member, which comprises the following general formula: [However, n in the formula represents a number from 0 to 5] A multifluorinated epoxy resin and a curing agent, or a mixture of the above multifluorinated epoxy resin and another epoxy resin and a curing agent After heating, mixing, and defoaming a refractive index matching agent whose main components are, it is coated on one side of an optical member or inserted between optical members, and then heated and cured. The present inventors have discovered that a composition containing as main components a multifluorinated epoxy resin represented by the general formula and a curing agent, or a mixture of a multifluorinated epoxy resin and another epoxy resin, and a curing agent is developed. The present inventors have completed the present invention by discovering that the refractive index matching agent can be used as a refractive index matching agent that has excellent workability, does not flow and flow after curing, and has excellent long-term reliability. The multifluorinated epoxy resin represented by the general formula used in the present invention is a known resin that is partially commercially available. The present inventors have found that those in which n in the general formula is in the range of 0 to 5 have the same effect in the above-mentioned uses of the present invention. Examples of other epoxy resins used in the present invention include diglycidyl ether of bisphenol A, phenol novolac, and diglycidyl ether of polyglycol. Examples of the curing agent used in the present invention include amine compounds such as triethylenetetramine, polyamide resin compounds, and acid anhydride compounds such as methylnadic anhydride. The amount of curing agent is determined by adhesive strength, water resistance, moisture resistance,
From the viewpoint of obtaining an adhesive composition with excellent heat resistance, the amount is preferably 0.8 to 1.0 equivalent per equivalent of epoxy resin. In the present invention, a curing accelerator such as benzyldimethylamine and 2-ethyl-4-methylimidazole may be added as necessary. The amount of the curing accelerator to be blended is preferably 0.5 to 2 parts by weight per 100 parts by weight of the epoxy resin. In addition, various diluents, modifiers, extenders, softeners, etc. can also be appropriately blended. [Example] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Examples 1 to 3 Multifluorinated epoxy resin represented by the general formula (epoxy equivalent: 225, n=0) [hereinafter abbreviated as FEp]
An epoxy resin containing diglycidyl ether of bisphenol A (manufactured by Yuka Ciel Epoxy Co., Ltd., Epicoat 828) having an epoxy equivalent of 189 was prepared in the proportions shown in Table 1 below, and these epoxy resins 100
50 parts by weight of a polyamide resin compound (Versamide V-140, manufactured by Henkel Japan Co., Ltd.) as a curing agent was added to each part by weight, and three types of optical adhesive compositions were prepared by heating, mixing, and defoaming. The resulting optical adhesive compositions were cured by heating at 90°C for 4 hours, and the shear adhesive strength to quartz, the glass transition temperature of the compositions, the refractive index, and the surface tension of the epoxy resin were investigated. Ta. The results are also listed in Table 1. The comparative example in Table 1 is an adhesive composition obtained by blending the same amount of the same curing agent as in the example with an epoxy resin consisting only of Epicoat 828 manufactured by Yuka Ciel Epoxy Co., Ltd.

〔Effect of the invention〕

As detailed above, the present invention provides an optical system that has high light transmittance, excellent adhesive strength, heat resistance, and wettability to adherends, and is capable of changing the refractive index over a wide range as necessary. A method for manufacturing a member can be provided.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of a conventional V-groove connection, Figure 2 is a perspective view thereof, Figure 3 is a schematic diagram of laser light entering an optical fiber, and Figure 4 shows the relationship between transmittance and wavelength. Figure 5 is a graph showing the relationship between thickness and transmittance, graphs 6, 8, 10, 12, 14 to 16.
Each figure is a graph showing the relationship between matching agent thickness and reflectance,
Fig. 7 is a diagram of a combination of prisms, Fig. 9 is a schematic diagram of one prism system, Fig. 11 is a schematic diagram of a self-occurring lens system, and Fig. 13 a and b shows the joining of a self-occurring lens and an optical fiber. FIG. 1 : Optical fiber, 2: V groove, 3: Epoxy resin, 4: Matching oil, 5: Instant adhesive, 6
A to 6C: Lid, 7: V-groove base, 8 : Laser diode, 9: Prism, 10: Refractive index matching agent,
13: Self-cleanse.

Claims (1)

[Claims] 1. The following general formula: [However, n in the formula represents a number of 0 to 5] and a curing agent, or a mixture of the above multifluorinated epoxy resin with another epoxy resin and a curing agent. After heating, mixing, and defoaming a refractive index matching agent mainly composed of Method.