JP3580581B2 - How to fix optical element to holder - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for fixing an optical element such as a lens, an optical crystal, a prism, or an optical isolator to a holder.
[0002]
[Prior art]
Conventionally, when an optical element such as a lens, a polarizer, an optical crystal, a prism, and an optical isolator is used, the optical element is used by being fixed to a holder. This is to facilitate handling, position adjustment, and fixing to other elements, and to improve accuracy, strength, reliability, and the like.
[0003]
The method of fixing the lens to the holder is conventionally performed by using a low-melting glass. Specifically, as shown in the plan views of FIGS. 5A and 5B and the cross-sectional view taken along the line AA, After the lens 13 is disposed on the holder 11, the outer periphery of the lens 13 is filled with powdered or powdered low-melting glass 12 and heated and melted to fix the lens 13. Was.
[0004]
Further, as shown in the perspective view of FIG. 6, a washer-shaped preform 14 of low-melting-point glass having a shape just fitting in the filling portion of the low-melting-point glass 12 is fitted between the lens 13 and the holder 11. After that, there is also a method of fixing the lens 13 by heating and melting the preform 14 of the low melting point glass.
[0005]
When light from a light source is transmitted through an optical system, a part of the signal light is reflected by a lens, an end face of an optical fiber, a bent portion, or the like, and returns to the laser light source to generate noise. An optical isolator is used to remove such reflected return light. As shown in the schematic cross-sectional view of FIG. 7, the optical isolator is configured by, for example, sequentially arranging a first polarizer 16a, a Faraday rotator 17, and a second polarizer 16b. These may be assembled using an adhesive, but are often joined using solder or low-melting glass due to the problem of misalignment due to temperature change and generation of gas contained in the adhesive.
[0006]
FIG. 7 shows an example in which an optical isolator and a holder are joined with low melting point glass. In this assembling, a first polarizer 16a, a holder 11a, and a Faraday rotator 17 are previously placed in a magnet 15 as a sub-assembly A. The second polarizer 16b is fixed to the holder 11b by heating with the low-melting glass 12, and the sub-assemblies A and B are combined as shown in FIG. Then, either the first polarizer 16a or the second polarizer 16b is rotated to adjust the angle of the plane of polarization of each other, and then joined.
[0007]
[Problems to be solved by the invention]
However, when the optical element is fixed by using powder or paste-like low-melting glass as shown in FIGS. 5 and 7, it is very difficult to adjust the amount of the low-melting glass 12 and apply it to a desired portion. In some cases, it adheres to the surface of the optical element during application, deteriorating the characteristics.
[0008]
On the other hand, when a low-melting-point glass preform 14 as shown in FIG. 6 is used, the work is easy without the trouble of adjusting the amount and a coating device, but the shape of the low-melting-point glass preform 14 is made small. It is difficult to mold to accurate dimensions if it is less than a few mm, so it becomes distorted, twisted, warped, and in some cases cannot be molded. There was a problem that it could not be handled. In addition, since the low-melting glass preform 14 has a low strength in shape, it may be broken during transportation before melting and fixing, and shards may be generated during the work, and may adhere to the optical element surface and deteriorate the characteristics. There was also a possibility to make it.
[0009]
For example, FIG. 8B is a cross-sectional view illustrating a case where the lens 13 is fixed using the deformed low-melting glass preform 14a. , The characteristics are degraded. FIG. 8A is a cross-sectional view of the preform 14a before being heated and melted.
[0010]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and in a holder having a hollow portion having a step, when an optical element is fixed to the step, bonding of the optical element to the step is performed. This is a method in which a low-melting glass is pre-filled in a part, the optical element is installed, and then the low-melting glass is heated and melted to fix the optical element. Further, in a holder having a hollow portion having a stepped portion, a plate-shaped low-melting glass is arranged on the upper surface of the holder so as to cover the hollow portion, and when pressed from above, the joining of the optical elements of the stepped portion is performed. The low-melting point glass was filled only by pressing using a mold having such a shape that the low-melting point glass remains, and the optical element was fixed by heating and melting the low-melting point glass after installing the optical element. Is the way.
[0011]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIGS. 1 to 4 show three embodiments of the present invention, wherein the same members are denoted by the same reference numerals.
[0013]
1A and 1B show a structure of a first embodiment of the present invention. FIG. 1A is a plan view of a holder 1 after a low-melting glass 2 is integrally formed, and FIG. 1B is a cross-sectional view taken along line AA of FIG. (C) is a cross-sectional view taken along line AA after the optical element 3 is provided, and the low-melting glass 2 is heated and melted to fix the optical element 3.
[0014]
According to the present invention, before the optical element 3 is disposed in the holder 1, the low melting point glass 2 is filled in advance in the joining portion, so that adjustment and handling of the amount of the low melting point glass 2 become very easy. Can be easily adjusted so that the low-melting glass 2 does not flow out to the surface of the device, and the small-sized holder 1 can be filled with the low-melting glass 2 with high accuracy, so that the optical element 3 can be fixed with high accuracy. In this embodiment, the optical element 3 is placed on the stepped portion of the holder 1 until the optical element 3 is fixed. However, a jig is inserted from the lower side of the hollow portion and placed on the upper surface of the jig. You may let it.
[0015]
FIG. 2 is a configuration diagram showing a step of filling the low melting point glass 2. As shown in FIG. 2A, the holder 1 is set in the mold 4b, and as shown in FIG. 2B, the low-melting glass 2 formed into a sheet is placed on the holder 1 and FIG. As shown in C), molding is performed by pressing with a mold 4a from above while heating. The mold 4a is shaped so that the low-melting glass 2 remains only at the joint between the holder 1 and the optical element 3 when pressed from above. The thickness of the plate-like low-melting glass 2 may be determined according to the thickness of the low-melting glass 2 to be filled in the holder 1.
[0016]
Even if the low melting glass 2 is filled in the holder 1 by such a process and the thickness of the low melting glass 2 is small, since the low melting glass 2 is integrated with the holder 1, it does not collapse during work or transportation. Processing accuracy of submicron or less is possible, and miniaturization and high precision of parts are realized.
[0017]
3A and 3B are views showing a second embodiment of the present invention, in which FIG. 3A is a plan view of the holder 1 after the low-melting glass 2 is filled, and FIG. 3B is a sectional view taken along line AA of FIG. (C) is a cross-sectional view taken along line AA after the optical element 3 is provided, and the low-melting glass 2 is heated and melted to fix the optical element 3.
[0018]
In this embodiment, a groove B is provided in a portion of the holder 1 filled with the low melting point glass 2. The groove B further makes it difficult for the low-melting glass 2 to flow into the surface opening diameter of the optical element 3, so that the optical characteristics are not further deteriorated.
[0019]
FIG. 4 is a sectional view showing a third embodiment of the present invention, and is a sectional view showing a case where an optical isolator is fixed to a holder. In the case of an optical isolator, high reliability is required for communication, and in particular, bonding with low melting point glass, which is more reliable than solder, is effective. In this optical isolator, a first polarizer 6a, a Faraday rotator 7, and a second polarizer 6b are provided in a cylindrical magnet 5. The first polarizer 6a is fixed to the holder 1a having the groove structure shown in the second embodiment via the low-melting glass 2a that is heated and melted. The Faraday rotator 7 is fixed to the holder 1b via the low-melting glass 2b, and is pre-assembled with the first polarizer 6a and the magnet 5 as a sub-assembly A. Also, the second polarizer 6b is fixed to the holder 1c having the groove structure shown in the second embodiment via the low-melting glass 2c, and is assembled as a sub-assembly B. The sub-assemblies A and B are joined together, the angle of the polarization plane of the first polarizer 6a and the second polarizer 6b is adjusted and fixed. In addition, the fixing method via the low melting point glass 2a, 2b, 2c is similar to the first embodiment or the second embodiment, and the low melting point glass 2a, 2b, 2c is filled.
[0020]
The optical isolator manufactured as described above can obtain the same effects as those of the first and second embodiments.
[0021]
【The invention's effect】
As described above, according to the method for fixing the optical element to the holder of the present invention, the low melting point glass is pre-filled in the bonding portion between the holder and the optical element, and the low melting point glass is heated and melted after the optical element is installed. Because it is a method of fixing the optical element, or after arranging a plate-like low-melting glass on the upper surface of the holder and pressing from above so that the low-melting glass remains only at the joint between the holder and the optical element, Since the optical element is installed and the low-melting glass is heated and melted to fix the optical element, it is very easy to adjust the amount and fill the desired site, and the low-melting glass is unnecessary. There is no need to worry about adhesion to the material, and molding can be performed with high accuracy even in a small size.
[Brief description of the drawings]
1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a plan view, FIG. 1B is a sectional view taken along line AA of FIG. 1A, and FIG. 1C is a sectional view taken along line AA of FIG. FIG.
FIG. 2 is a configuration diagram showing a manufacturing process of the present invention.
3A and 3B show a second embodiment of the present invention, wherein FIG. 3A is a plan view, FIG. 3B is a sectional view taken along line AA of FIG. 3A, and FIG. 3C is a sectional view taken along line AA of FIG. FIG.
FIG. 4 is a sectional view showing a third embodiment of the present invention.
FIG. 5 is a view showing a state where a conventional optical element is fixed to a holder.
FIG. 6 is a perspective view showing a conventional low-melting glass preform.
FIG. 7 is a schematic sectional view of a conventional optical isolator.
FIG. 8 is a diagram showing a state where a conventional optical element is fixed to a holder.
[Explanation of symbols]
1, 1a, 1b, 1c, 11, 11a, 11b: Holder 2, 2a, 2b, 2c, 12, 12a, 12b: Low melting point glass 3: Optical element 4a, 4b: Mold 5, 15: Magnet 6a, 16a : First polarizer 6b, 16b: second polarizer 7, 17: Faraday rotator 13: lens 14, 14a: preform B of low melting point glass: groove

Claims (1)

In an optical element installation holder having a hollow portion having a stepped portion, the optical element is fixed to the stepped portion by performing the following steps (1) to (3). How to fix the element to the holder.
(1) a step of disposing a plate-like low-melting glass on the upper surface of the holder so as to cover at least the entire hollow portion, with the surface of the holder fixing the optical element facing upward; Pressing using a mold having a shape such that the low-melting glass remains only at the joint portion of the optical element in the portion, and filling the low-melting glass in the step, (3) after installing the optical element in the step Fixing the optical element by heating and melting the low-melting glass.

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