JPH053419B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method of manufacturing a rod lens provided in various optical devices used in combination with, for example, an optical fiber. (Prior art) Optical switch incorporated into optical communication or optical measurement equipment,
Optical branching circuits, optical demultiplexing circuits, etc. use distributed index rod lenses (trade name: self-occurring lenses) to convert the light rays from the light source or optical fiber into parallel beams, and to focus the parallel beams to a single point. There is. Both end surfaces of the rod lens mentioned above are flat,
The following method has been conventionally known as a method for processing the end face of such a rod lens, which has a lens effect similar to that of a spherical lens. This method involves bundling a large number of glass rods with a refractive index distribution, which are the materials for rod lenses, surrounding the bundle with smooth glass plates and gluing the edges of the glass plates. Adhesive in a fluid state in the gap between the glass rods held within the enclosed space;
For example, balsam or the like is poured in, the adhesive is allowed to cool and solidify, and then the glass rods and glass plates are cut into slices to form a block piece with a large number of glass rods surrounded by a glass frame. Sanding, polishing, etc. are performed on both end faces of the rod glass, and then the block pieces are immersed in an organic solvent to release the adhesion between the rod glasses to obtain individual rod glasses. The rod glass is attached to a fixture, set in a vapor deposition tank, and both end faces of the rod glass are coated with a non-reflective film to protect the light entrance and exit surfaces, eliminate reflections of external light, and ensure the clarity of images, etc. There is. (Problems to be Solved by the Invention) As mentioned above, in the conventional method, the balsam used to temporarily bond the glass rods together cannot withstand the deposition temperature. The process of cutting the rod into a predetermined size and polishing the end face can process many glass rods at the same time, but the process after this, that is, applying an anti-reflection coating to the end face of the rod glass cut to a predetermined size. The process of vacuum-depositing the anti-reflection film, the process of inspecting the surface on which the anti-reflection film is formed, and the process of packaging the rod lenses all require handling of the rod lenses individually. As a result, first of all, it takes time and effort to form the anti-reflection film, and inspection and packaging are also troublesome and difficult to automate.Furthermore, since each rod lens is handled individually, there is a chance that the end face of the rod lens may be scratched or foreign matter may adhere to it during handling. There is a lot of waste, and the product yield also decreases. (Means for solving the problems) In order to solve the above-mentioned conventional problems, the present invention has two features.
The glass rods, which are the raw materials for rod lenses, are temporarily glued together using a different type of adhesive. That is, a first adhesive that does not soften at the temperature at which the coating is deposited (approximately 350°C), and a second adhesive that melts in a solvent (which does not melt the first adhesive) are used. After temporarily gluing the glass rods together and performing cutting and polishing in this state, only the second adhesive is eluted and the coating is applied to the end face of the rod glass in a vacuum while the block piece holding the rod glass in the glass frame is still in place. I decided to use vapor deposition. (Example) Examples of the present invention will be described below in order of steps with reference to the accompanying drawings. As shown in Fig. 1, the first step of the method of the present invention is to stack and bundle a large number of gradient index glass rods 1 with a diameter of 0.5 to 5.0 mm and a length of 50 to 300 mm. As shown in Figure 2, the smooth surface is surrounded by glass plates 2..., the edges of these glass plates 2... are glued with a heat-resistant instant adhesive, and a large number of glass plates are placed in the space surrounded by the glass plates 2... An assembly 3 in which the glass rod 1 is tightly held is obtained. The assembly 3 obtained as described above is immersed in a base agent such as a silicone primer, and then assembled in a first adhesive solution that does not soften at the non-reflective film deposition temperature (approximately 350°C), which will be described later. Immerse solid 3. Here, as the first adhesive, in addition to silicone varnish solution (varnish solid content 40%, xylene 60%), modified silicone varnish, silicone resin, modified silicone resin, polyimide varnish, polyimide resin, heat-resistant epoxy varnish, or Examples include solutions such as heat-resistant epoxy resins. As described above, the assembly 3 is placed in the first adhesive solution.
After soaking, the assembly 3 was pulled up, air-dried, and then baked (at 200°C for 1 hour). As shown in Figure 3, the glass rods 1...
Temporarily adhere with adhesive 4. Thereafter, as shown in FIG. 4, the gap S is filled with a second adhesive 5 that is soluble in an organic solvent. Here, in addition to balsam, the second adhesive is pine resin,
Examples include wax, rosin, and paraffin. In addition, by filling the gap S with the second adhesive 5, if a gap exists in the later polishing process, chips etc. will enter the gap, and the glass rod 1
There is no risk of injury. Next, a large number of glass rods 1 temporarily bonded with the first adhesive 4 and the second adhesive 5 are assembled into an assembly 3.
A block piece 8 is obtained by cutting along the length of a glass rod as shown in FIG. 5 and holding a large number of rod glasses 6 with a glass rod 7 as shown in FIG.
get. After that, the block piece 8 remains as the rod glass 6...
The end faces of the block 8, that is, the faces that will become the entrance and exit faces, are chamfered, sanded, and polished, and after this work is completed, the block piece 8 is immersed in an organic solvent. This organic solvent is selected to dissolve only the second adhesive 5 but not the first adhesive 4. Specifically, balsam is used as the second adhesive 5.
When pine resins are used, it is preferable to use alcohols such as ethanol, and when waxes and rosins are used, it is preferable to use chlorinated solvents such as trichlorethylene and Daiflon. Then, by immersing the block 8 in an organic solvent, only the second adhesive 5 is eluted, and each rod glass 6 is still a porous block piece temporarily bonded with the first adhesive 4. 8 is obtained. Therefore, after wiping both sides of the porous block piece 8, that is, the portions that will become the entrance and exit surfaces of the rod lens, the block piece 8 is fitted into a vapor deposition jig and set in a vapor deposition tank. Then, a dielectric non-reflective film is coated on both end surfaces of the rod glass 6 under heating at about 350° C. to obtain the desired rod lens. Next, the block piece 8 is placed in a basket 9 as shown in FIG. 7, and immersed in a container 11 filled with a solvent 10 capable of dissolving the first adhesive 4. Here, as the solvent for dissolving the first adhesive 4, when silicone is used as the first adhesive 4,
It is preferable to use cellosolve solution of metal alcoholate, to use ethylenediamine or hydrazine when polyimide is used, and to use corrosive inorganic molten salt such as Zncl ₂ or ZnBr ₂ when epoxy is used. . By immersing the block piece 8 in the solvent for about one hour as described above, the first adhesive 4 bonding the rod lenses is eluted. However, each rod lens is still held in the glass frame 7, so one side of the block piece 8, that is, one end surface of many rod lenses, is inspected in this state, and then the block piece 8 is turned over and the other end surfaces of many rod lenses are inspected at the same time. inspect. Thereafter, either the block piece 8 is packaged, or the glass frame 7 is removed and the rod lenses are individually packaged. By the way, if the glass rods 1 are temporarily bonded by completely filling the gap S between the glass rods 1 using only the first adhesive 4 from the beginning, the filling process and elution process of the second adhesive are unnecessary. However, it cannot be said to be optimal for the following reasons. That is, FIG. 8 is a graph showing the relationship between the vapor deposition time and the ultimate degree of vacuum (gas generation amount). This shows the case of filling with only the first adhesive, and according to the present invention, it takes a short time to reach a predetermined degree of vacuum. This is because a portion of the first adhesive vaporizes and generates gas due to the high temperature and low pressure used during vapor deposition, and if the amount of the first adhesive is small, less gas is generated. That will happen. If a large amount of gas is generated, it will adhere to the end face of the rod lens and cause the surface to become dirty, so it is preferable to suppress the generation of gas as much as possible. Therefore, the glass rods 1 are temporarily bonded using enough first adhesive to exert the holding force required for vapor deposition. The reason why the second adhesive is filled in the gaps that are not filled with the first adhesive is to prevent chips from entering as described above and to ensure holding power during cutting and polishing. It is. Furthermore, in the examples, a solvent was used as a means for removing the first adhesive, but the first adhesive was removed using oxygen gas or the like at a temperature that does not impair the optical properties of the anti-reflection film. It may also be disassembled. (Effects of the Invention) As described above, according to the method of the present invention, an anti-reflection film can be formed on a large number of rod glass end faces at the same time, and a large number of rod lens end faces can be inspected simultaneously, so production efficiency is greatly improved. Furthermore, the incidence of scratches on the lens end face can be greatly reduced. Such effects are shown in Tables 1 and 2 with specific numerical values.

【table】

[Table] These tables confirm the effects of the present invention, and even after making the rod lenses, the individual rod lenses are arranged in a honeycomb shape within the block piece, making it easy to automate the post-process. It is also effective.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a bundle of glass rods that are the raw materials for rod lenses, Figure 2 is a perspective view of an assembly in which a bundle of glass rods is surrounded by a glass plate, and Figure 3 is a perspective view of a bundle of glass rods. Figure 4 is an enlarged view showing the state in which the glass rod is temporarily bonded with the first adhesive and the second adhesive.
Enlarged view showing temporary adhesion with adhesive, No. 5
The figure is a perspective view of the cut assembly, Figure 6 is a perspective view of the block piece, Figure 7 is a perspective view showing the first adhesive elution process, and Figure 8 is a graph showing the relationship between vapor deposition time and ultimate vacuum degree. It is a graph showing a relationship. In addition, in the drawing, 1 is a glass rod, 2 is a glass plate, 3
4 is an assembly, 4 is a first adhesive, 5 is a second adhesive, 6 is a rod glass, 7 is a glass frame, and 8 is a block piece.

Claims (1)

[Claims] 1. A step of bundling a large number of lens material glass rods and holding the periphery of the bundle of glass rods with a glass plate,
temporarily bonding a large number of glass rods held by the glass plate with a heat-resistant first adhesive and a second adhesive that dissolves in a solvent that does not dissolve the first adhesive; A large number of glued glass rods are cut into predetermined dimensions in the length direction of the glass rod together with the glass plates, and a block piece is created by surrounding the glass frame with a glass frame, and the end faces of the rod glass that make up the block piece are polished. a step of treating the block piece with the solvent to elute the second adhesive; and depositing a coating film on the end face of the rod glass constituting the porous block piece after the second adhesive has been eluted. and a step of treating the porous block piece with a solvent to dissolve the first adhesive and release the temporary adhesion between the rod glasses. 2. The step of temporarily bonding a large number of glass rods is first to temporarily bond the glass rods together with a heat-resistant first adhesive leaving a gap, and then filling this gap with a solvent that does not dissolve the first adhesive. 2. The method for manufacturing a rod lens according to claim 1, wherein the second adhesive is filled with a meltable second adhesive.