JPH0566303A - Manufacture of polarized light separating prism - Google Patents

Abstract

PURPOSE:To mass-produce polarized light separating prisms by adhering plural flat plates for the prism and cutting and polishing them. CONSTITUTION:A polarized light separating film 14 is formed of a dielectric multi-layered film, etc., on one main surface of the flat plate 12 for the prism which is made of glass, etc. Then the flat plates 12 for the prism are laminated so that the polarized light separating films 14 are on the same sides and adhered together with optical adhesives. In this case, the flat plates 12 for the prism are laminated by shifting by a width corresponding to the thickness, and cut along a plane 15 slanting at 45 deg. to the main surfaces, and the 1st cut surface is polished into a specular surface. Then the 1st cut surface 19 is adhered tentatively to a dummy substrate 16 and they are cut along planes 20 containing contact sides 18 between the dummy substrate 16 and polarized light separating films 14 and the 2nd cut surfaces are polished into specular surfaces. Then the dummy substrate 16 is removed and the 2nd cut surfaces are adhered tentatively to a dummy substrate 22 and they are cut along planes 26 which are perpendicular to the 2nd cut surfaces and contains the exposed sides 24 of the polarized light separating films 14 in the 2nd cut surfaces and the cut surfaces are polished into secular surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polarization separation prism. In the field of optical communication or optical transmission, a polarization separation prism is often used as a constituent element of an optical device such as an optical isolator. The polarization splitting prism splits the incident light into polarization components whose polarization planes are orthogonal to each other,
It is for emitting these polarization components in different optical paths. A method for manufacturing a polarization splitting prism suitable for mass production is being sought in order to reduce the cost and make the quality of an optical device including the polarization splitting prism uniform.

[0002]

2. Description of the Related Art An example of the structure of a conventional general polarization separation prism is shown in FIG. This polarization separation prism is configured by interposing a polarization separation film 6 between the slopes of the triangular prisms 2 and 4 and integrating them.

As a conventional method of manufacturing such a polarization separation prism, a polarization separation film 6 made of a dielectric multilayer film or the like is previously formed on one of the slopes of the triangular prisms 2 and 4, and polarization separation is performed. A general method is to integrate a triangular prism on which a film is formed and a triangular prism on which a polarization separation film is not formed with an optical adhesive.

[0004]

By the way, as a method of manufacturing a triangular prism which is a constituent element of a polarization separation prism, a method of heating a glass material to press it in a semi-molten state and then polishing it, and recently, a flat plate A method of obtaining a plurality of triangular prisms from glass (JP-A-2-154203) is known.

However, when the polarization separating prism is manufactured by the above-mentioned conventional method using the triangular prisms manufactured by these methods, for example, the positional deviation of the triangular prism at the time of bonding and the variation of the coating amount of the adhesive are caused. Due to this, there arises a problem that the quality becomes non-uniform, or the manufacturing workability deteriorates as the prism becomes smaller, and it becomes difficult to reduce the price. Thus, the conventional method cannot be said to be suitable for mass production.

The present invention was created in view of such circumstances, and an object thereof is to provide a method of manufacturing a polarization separation prism suitable for mass production.

[0007]

A method of manufacturing a polarization separation prism according to the present invention comprises a first step of forming a polarization separation film on one main surface of a plurality of prism flat plates, and a plurality of the prism flat plates. Is laminated so that the polarization separation films are on the same side, and they are adhered to each other, and the plurality of prism flat plates are cut at a plane inclined at 45 ° with respect to the main surface. The third step of mirror-polishing the cut surface of No. 1 and the first flat plate for prisms
And a plurality of prisms, the fourth step of cutting along the plane perpendicular to the cut surface of the first cut surface and parallel to the exposed side of the polarization separation film in the first cut surface, and polishing the second cut surface to a mirror surface. A fifth step of cutting the flat plate perpendicular to the second cut surface and a plane including the exposed side of the polarization separation film in the second cut surface, and mirror-polishing the third cut surface; Are to be processed in this order.

[0008]

According to the method of the present invention, it becomes possible to mass-produce the polarization separation prism, and it becomes possible to stabilize the quality and reduce the cost.

[0009]

The preferred embodiments of the present invention will be described below. FIG. 1 is an explanatory view of a manufacturing procedure of a polarization separation prism in the embodiment of the present invention. First, as shown in FIG. 1A, a polarization separation film 14 made of a dielectric multilayer film or the like is formed on one main surface of a prism flat plate 12 made of glass (for example, BK7). The size and number of the prism flat plates 12 are set according to the number of polarization separation prisms to be manufactured. Further, in consideration of cutting and polishing margins, the thickness of the prism flat plate 12 is slightly smaller than 1 / √2 times the dimension of one side when the shape of the polarization separation prism to be manufactured is, for example, a cube. Largely set.

Next, as shown in FIG. 1 (B), the prism flat plates 12 each having a polarization separation film 14 formed on one main surface are laminated so that the polarization separation films 14 are on the same side. It is adhered to by an optical adhesive. In this embodiment, in order to increase the manufacturing yield, the prismatic flat plates 12 are stacked with a shift corresponding to the thickness thereof.

Then, the laminated flat plate 1 for prisms is used.
2 is cut at a plane 15 inclined by 45 ° with respect to the above-mentioned main surface, and the first cut surface is mirror-polished. As a polishing method, a method using a diamond wheel (grain size 600 to 800) can be adopted (the same applies hereinafter).

Next, as shown in FIG. 1C, the above-mentioned first cut surface (reference numeral 19) is temporarily adhered to the dummy substrate 16 for cutting, and is perpendicular to the first cut surface 19 and is a dummy substrate. 1
The flat plate 12 for each prism is cut along a plane 20 including the contact side 18 of the polarization separation film 14 and the polarizing plate 6. Then, the second cut surface is also mirror-polished.

In this case, the dummy substrate 16 may be separated by cutting and mirror polishing may be performed before removing the separated pieces of the dummy substrate, or the dummy substrate 16 may not be separated,
Mirror polishing may be performed after removing the dummy substrate.

In this embodiment, the cutting is performed on the plane including the contact side 18 of the dummy substrate 16 and the polarization separation film 14 in order to obtain the polarization separation prism even from the end of the cut portion. This is because. Therefore, when the improvement of the manufacturing yield is not taken into consideration, the contact side 1 is parallel to the contact side 18 between the dummy substrate 16 and the polarization separation film 14.
You may cut | disconnect on the plane which does not include 8.

In the present embodiment, the first cut surface 1
9 is temporarily adhered to the dummy substrate 16 when the cutting is performed on the plane including the contact side 18 between the dummy substrate 16 and the polarization separation film 14 and the prism flat plate 12 is provided in the vicinity of the contact side 18. This is to prevent the breakage.

Thereafter, the dummy substrate 16 is removed from the above-mentioned cut portion, and this cut portion is formed into another dummy substrate 22 by the mirror-polished second cut surface as shown in FIG. 1 (D). Temporarily bond. Then, the prism flat plate is cut along a plane 26 which is perpendicular to the second cut surface and includes the exposed side 24 of the polarization separation film 14 on the second cut surface, and the third cut surface is mirror-polished.

The reason why the second cut surface is temporarily adhered to the dummy substrate 22 for cutting is the same as the reason why the dummy substrate 16 is used in the step of FIG. 1C.
The blocks separated from each other through such a series of steps will be referred to as prism pieces 30. This prism piece 30 can be used as it is as a polarization separation prism because its four main surfaces are mirror-polished in a state of being removed from the dummy substrate 22.

When it is desired to obtain a cubic polarization splitting prism which is smaller than the prism piece 30,
The prism piece 30 may be cut along a plane 28 perpendicular to the third cut surface and separated from each other by a predetermined distance, and the fourth cut surface may be mirror-polished. By doing so, it is possible to obtain the polarization splitting prism 32 having a cubic shape as shown in FIG.

In this embodiment, as shown in FIGS. 1 (A) and 1 (B), a plurality of prism flat plates each having a polarization splitting film formed on one main surface are laminated. However, it is possible to manufacture a polarization separation prism suitable for mass production without using this method. That is, after alternately laminating a prism flat plate having a polarization separation film formed on both main surfaces and a prism flat plate having no polarization separation film formed on any of the main surfaces, the third step and subsequent steps are performed. The method adapted to carry out the steps of is substantially the same as the method of the present invention.

[0020]

As described above, according to the present invention,
It is possible to provide a method for manufacturing a polarization separation prism suitable for mass production. As a result, it is possible to provide a polarization separation prism that has uniform quality and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a manufacturing procedure of a polarization separation prism in an example of the present invention.

FIG. 2 is a perspective view showing a configuration example of a polarization separation prism.

[Explanation of symbols]

 12 Flat plate for prism 14 Polarization separation film 16, 22 Dummy substrate

Claims (4)

[Claims] 1. A first step of forming a polarization separation film (14) on one main surface of each of a plurality of prism flat plates (12); The second step of laminating so that 14) are on the same side and adhering them to each other;
A third step of cutting along the inclined plane (15) and mirror-polishing the first cut surface, and the plurality of prism flat plates (12) above the first cut surface (19)
And the polarization splitting film (1
A fourth step of cutting along a plane (20) parallel to the exposed side of 4) and mirror-polishing the second cut surface, and the plurality of prism flat plates (12) on the second cut surface. A fifth step of cutting at a plane (26) which is vertical and includes the exposed side (24) of the polarization separation film (14) in the second cut surface, and mirror-polishs the third cut surface. A method for manufacturing a polarization separation prism, which is characterized in that the steps are performed in this order. 2. The method according to claim 1, wherein the cutting in the fifth step is performed by temporarily adhering the second cut surface to a dummy substrate (22). 3. In the cutting in the fourth step, the dummy substrate (16) and the polarization splitting film (14) are prepared with the first cutting surface (19) temporarily adhered to the dummy substrate (16). Contact edge of (1
The method for manufacturing a polarization separation prism according to claim 1 or 2, which is performed on a plane including 8). 4. The prism piece (30) obtained after passing through the first to fifth steps is cut along a plane (28) perpendicular to the third cut surface, and the fourth cut surface is obtained. 4. The method for producing a polarization separation prism according to claim 1, wherein the cube-shaped polarization separation prism (32) is obtained by mirror polishing.