JP2000147222A - Production of wollaston prism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce Wollaston prisms in a good yield by stepwise laminating substrates while dislocating the substrates in the facial direction, bonding the substrates to each other and cutting the resultant laminated body along sections having a required tilt angle at a prescribed pitch in the facial direction. SOLUTION: Substrates 30, 31 are alternately laminated while aligning the cut ends at a prescribed tilt angle and applying a UV-curing adhesive 36 between the substrates 30, 31, and the resultant laminated body is stuck together by irradiation with UV. The laminated body 40 is then cut along sections 45 having a required tilt angle at a prescribed pitch to form plural plate-like divided laminated bodies 50. The laminated bodies 50 are laminated in an aligned state, temporarily fixed with a temporary fixing material and cut to form plural plate-like temporarily fixed connected bodies. The upper and lower surfaces of the connected bodies are ground and polished by a required amount. The connected bodies are further cut in a direction perpendicular to the temporarily fixed surfaces at a prescribed pitch in the facial direction to form cylindrical temporarily fixed connected bodies with Wollaston prisms 1 temporarily fixed and connected in a cylinder shape and the temporary fixing material is removed to separate the Wollaston prisms.

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 Wollaston prism, and in particular, greatly improves a conventional complicated manufacturing method in which a crystal is formed into a required shape by grinding and polishing and then joined. The present invention relates to a method for manufacturing a Wollaston prism that improves productivity and reduces costs.

[0002]

2. Description of the Related Art A Wollaston prism is composed of a crystal made of anisotropic crystal such as quartz and having a predetermined optical axis, which is bonded along a predetermined optical axis. Is an optical device that separates and emits linearly polarized light that is orthogonal to each other. FIG. 4 is a front view, a bottom view, a plan view, left and right side views, and a rear view showing an example of the configuration of the Wollaston prism. The Wollaston prism 1 is a plate-like body having a rectangular front surface and a trapezoidal columnar shape. Crystals 2, 3 of
Are joined and integrated by inclined surfaces. The optical axis directions of the respective crystal bodies 2 and 3 are different as shown by arrows. FIG. 5 shows an example of a method of using the Wollaston prism. In this example, a laser diode or the like is illustrated using an optical device in which a cubic beam splitter 10 is joined and integrated on one main surface of the Wollaston prism 1. Light emitted from a light source that does not emit light is irradiated onto a medium such as the optical disk 15. Polarization separation film 11 of beam splitter 10
Transmits the incident light from the light source while the optical disk 15
The light after the polarization and the polarization plane is rotated is reflected by the polarization separation film 11 in the orthogonal direction without being transmitted. Since the Wollaston prism 1 is bonded to the emission surface of the beam splitter 10, the light emitted from the beam splitter 10 is transmitted to each of the crystals 2 and 3 constituting the Wollaston prism 1.
And the separated outgoing light is received by each of the light receiving elements 5, 6, and 7.

FIG. 6A is a view showing a conventional method of manufacturing such a Wollaston prism.
The crystal 21 is ground and polished along a dotted line while a plate-shaped crystal 21 (both surfaces of which are mirror-finished), which is the original shape of the crystal 2, is temporarily adhered to a base 20 provided with Oa. Is performed to form a desired trapezoidal column shape, and peeled from the pedestal. Also, the crystal 3 is formed into a required trapezoidal shape by applying the same processing to the plate-shaped crystal as its original shape. The two trapezoidal columnar crystals 2 and 3 obtained in this manner are joined and integrated by UV adhesive or the like along their respective inclined surfaces as shown in FIGS. 6 (b) and 6 (c). Wollaston prism 1 is completed. The Wollaston prism uses lithium niobate LiNbO ₃ (hereinafter referred to as “LN”) as a material, has a thickness of about 1 mm, and has an inclination angle of about 10 degrees at the joint surface. In addition, as the Wollaston prism, besides one that joins trapezoidal columnar crystals, there is also one that is formed by joining inclined surfaces of triangular prismatic crystals. However, such a conventional manufacturing method is carried out by grinding and polishing a plate-like crystal having a small size, which is an extremely low productivity operation. It was a major cause of hindrance. Further, the processing accuracy and yield of products are poor, and improvement of these defects has been conventionally required.

[0004]

The problem to be solved by the present invention is to greatly reduce the conventional complicated manufacturing method of forming a crystal having an optical axis into a required shape by grinding and polishing and then joining the crystals. It is an object of the present invention to provide a method of manufacturing a Wollaston prism with improved productivity and reduced cost, and in particular, a structure in which two trapezoidal columnar (or triangular prismatic) crystals are joined and integrated by inclined surfaces. It is an object of the present invention to provide a method for manufacturing a Wollaston prism having high processing accuracy and excellent mass productivity.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is a trapezoidal or triangular prism made of a crystal having an optical axis, the inclination of two trapezoidal or triangular prisms having different optical axis directions. In a method of manufacturing a Wollaston prism having a rectangular front face formed by joining surfaces, a first rectangular-plate-shaped substrate having a crystal plate whose optical axis is parallel to a main surface of the crystal plate is provided. And a first mirror finishing step of mirror-finishing the upper and lower main surfaces of a rectangular flat plate-shaped second substrate made of a crystal plate having an optical axis having a predetermined inclination angle θ with respect to the main surface of the crystal plate. And, the second substrate and the first substrate are alternately stacked on the horizontal plane with the cut edges aligned, and the surface connecting the side edges of the stacked substrates is a required inclination angle with respect to the horizontal plane, that is, 90 degrees-(the inclination angle θ of the optical axis of the second substrate) A multi-layer stack in which the plane position is shifted in a stepwise manner so as to be inclined, and a laminate forming step of bonding between the substrates, and cutting the laminate formed by the laminate forming step along the required inclination angle A divided laminated body forming step of forming a plurality of plate-shaped divided laminated bodies by cutting at a predetermined pitch according to a surface, and an aligned state in which the plurality of divided laminated bodies formed in the divided laminated body forming step are aligned at edges. And then temporarily fixing between the divided laminated bodies with a temporary fixing material to form a temporarily-fixed laminate, and a temporarily-fixed laminate formed by the temporarily-fixed laminate forming step. By cutting the body at a predetermined pitch along a direction perpendicular to the cutting plane, a trapezoidal pillar-shaped first substrate portion and a second substrate portion are joined and integrated on an inclined surface to form a square pillar body. Plates connected in a shape A step of forming a plate-shaped temporary connection, forming a temporary connection, a second mirror-finishing step of mirror-finishing both upper and lower surfaces of the plate-shaped temporary connection, and a plate-shaped temporary connection connected to a mirror-finished surface By cutting at a predetermined pitch along a direction orthogonal to the temporary fixing surface, thereby forming a rod-shaped temporary fixing connected body in which the Wollaston prisms are temporarily connected in a rod shape, and the rod-shaped temporary fixing connected body forming step, A separation step of separating the individual Wollaston prisms by removing the temporary fixing material constituting the temporary fixing connection body. The invention according to claim 2 is characterized in that after the first mirror finishing step, an antireflection film and / or a matching film is formed on the main surfaces of the first substrate and the second substrate. . According to a third aspect of the present invention, after the second mirror finishing step, the first substrate and the second
An anti-reflection film and / or a matching film is formed on the main surface of the substrate. The invention of claim 4 is characterized in that paraffin is used as the temporary fixing material. The invention according to claim 5 is characterized in that the acute angle portion of the edge of the divided laminated body is cut in advance.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. 1 (a) to 1 (c) and FIG.
(a) thru | or (e) are process drawings for demonstrating the manufacturing method of a Wollaston prism. The present invention, as shown in FIG.
A Wollaston prism having a rectangular hexahedron in frontal shape formed by joining inclined surfaces of two trapezoidal column crystals each having a different optical axis direction and having a trapezoidal column crystal made of a crystal having an optical axis. It relates to a manufacturing method.
FIG. 1A is a perspective view showing the structure of a first substrate used in the manufacturing method of the present invention, and FIG. 1B is a perspective view showing the structure of a second substrate. Crystal plate 30a parallel to the main surface
The second substrate 31 has a predetermined inclination angle θ (for example, 10 degrees) with respect to the main surface of the crystal plate.
It is a rectangular flat plate composed of a crystal plate 31a having a degree (degree).
Each of the substrates 30 and 31 is provided with an anti-reflection film or a matching film, if necessary, after mirror-finishing the front and back surfaces of rectangular crystal plates (crystal bodies) 30a and 31a having a uniform thickness.
In the present invention, the same number of the first and second substrates are used, and the required steps are sequentially performed after the first and second substrates are alternately stacked. The anti-reflection film is a film formed to prevent irregular reflection of a mirror surface serving as a light incident and emission surface, and a matching film is used when bonding a plurality of crystals using an adhesive. This is a film for preventing a change in the refractive index of light transmitted through the crystal due to the above. As a material of each of the substrates 30 and 31, LN or an anisotropic crystal material such as quartz or rutile is used.

FIG. 1B is a view showing a laminated body forming step and a divided laminated body forming step.
0 ° -10 °), each board 3 with the same opening
0 and 31 are alternately stacked. That is, the jig 35 includes a horizontal plate-shaped base 35a and the base 3a.
Each of the substrates 30 and 31 having an inclined side wall 35b and the like that is fixed by being inclined upward at an inclination angle of 80 degrees from 5a, and having a mirror-finished surface facing upward, is sequentially laminated on the base 35a.
At this time, one edge of each of the substrates 30 and 31 is set to the inclined side wall 35b.
, The respective substrates 30 and 31 become a step-like stacked body 40 which is shifted by an equal distance in the plane direction. In other words, the laminated body has a substantially parallelogram front shape. The right figure in FIG. 1B shows a right side view. Before the lamination, a UV-curable adhesive 36 is applied between the substrates 30 and 31, and ultraviolet rays are laminated from an ultraviolet light source (not shown) in a state where the laminate 40 is pressed to spread the adhesive uniformly. The body is irradiated, the adhesive 36 is cured, and the laminate is bonded.
In this way, in the laminate forming step, the second substrates 31 and the first substrates 30 are alternately laminated on the horizontal surface with the same opening, and the surface connecting the side edges of the laminated substrates is the horizontal surface. In this case, the layers are stacked in a multi-stage manner by shifting the surface direction in a stepwise manner so as to incline by a required inclination angle, that is, 90 degrees− (the inclination angle θ of the optical axis of the second substrate), and bonding between the substrates is performed. I do. In the above embodiment, the inclination angle of the optical axis of the second substrate 31 is set to 10 degrees, but this is only an example.
In this example, the thickness of the substrate is about 1 mm,
The angle of inclination of the optical axis is naturally limited to about 10 degrees, but may be 20 degrees or 30 degrees depending on the usage. The greater the inclination angle, the wider the separation angle of the split light. When LN is used as the substrate material, a sufficient separation angle can be obtained even if the optical axis has a tilt of 10 degrees in relation to the refractive index. Conversely, when using quartz, if the tilt of the optical axis is about 10 degrees,
Since the separation angle is too narrow, it will need to be increased to about 45 degrees.

Next, as shown by a chain line in FIG. 1 (b), the laminate 40 formed by the laminate forming step is cut at a predetermined pitch (the pitch in the plane direction) by the cut surface 45 along the required inclination angle. ) To form a plurality of plate-shaped divided laminates 50 (divided laminate formation step). As a cutting means, a wire saw or the like is used. It is important to set the direction of the cut surface 45 to a direction orthogonal to the optical axis of the second substrate 31. FIG. 1C is a perspective view of the formed divided laminated body 50, and the divided laminated body 50 has a configuration in which each of the crystal bodies 30a and 31a processed into a rectangular rod shape is alternately connected in a plate shape. In addition, both edges of the divided laminated body 50 protrude at an acute angle and are easily damaged, and the broken crystal pieces cause various defects in a subsequent process, such as mixing into an adhesive surface, resulting in poor bonding, or during mirror processing. Incorporation into the machined surface causes problems such as scratching the machined surface. For this reason, it is preferable to remove the sharp edge along the cutting line 51 in advance.

Next, FIG. 2 (a) is a diagram showing a step of forming a temporarily-fixed laminated body and a step of forming a plate-shaped temporarily-fixed connected body. The provisionally-fixed laminated body forming step includes, after laminating the plurality of divided laminated bodies 50 formed in the divided laminated body forming step in an aligned state in which the ends are aligned, temporarily fixing each divided laminated body with a temporary fixing member 56. This is a step of forming the temporarily fixed laminated body 55. In this example, a plurality of divided laminates 50 are laminated on a horizontal base 57a of a jig 57, and the base 57a
Each of the divided laminates 50 is laminated in an aligned state along the side wall 57a erected at an angle of 90 degrees above. Each split laminate 50
The space is temporarily fixed by a temporary fixing member 56 such as paraffin. In addition, the plate-shaped temporarily connected body forming step is a step of forming a plurality of plate-shaped temporarily connected bodies 61 by cutting along the cut surface 60 shown in FIG. In this step, the temporarily-fixed laminate 55 formed in the above-mentioned temporarily-fixed laminate forming step is cut at a predetermined plane direction pitch along a direction (cut surface 60) orthogonal to the cut surface 45 in FIG. 1B. Thus, the trapezoidal columnar first substrate portion (crystal 30
This is a step of forming a plate-shaped temporarily connected body 61 in which trapezoidal columns in which a) and a second substrate portion (crystal body 31a) are joined and integrated on an inclined surface are connected in a plate shape. As the cutting means, for example, a wire saw is used. In this example, since the purpose is to form a Wollaston prism having a rectangular front shape by joining trapezoidal columnar crystals at inclined surfaces, the cutting position by the cut surface 60 is determined by the respective crystals 30a and 31a. Is considered so as to be trapezoidal. However, in the case where a Wollaston prism having a rectangular front shape is formed by joining crystals of right triangular prisms with inclined surfaces, for example, a cut surface 65 Will be cut along. FIG. 2 (b) is a front view showing the structure of each plate-shaped temporary connection body 61 cut out in the process of FIG. 2 (a).
(c) is a front view showing a grinding / polishing / mirror finishing step.
The plate-like temporary fixing joint 61 formed in the step of forming the plate-like temporary fixing joint shown in FIG. 2 (a) is initially a thick plate as shown in FIG. 2 (b). By polishing, the thin plate-shaped temporary fixing joint 61A shown in FIG.
To form Both surfaces of this thin plate-shaped temporary connection body 61A are mirror-finished (second mirror-finish step), and an anti-reflection film is formed as necessary.

Next, FIG. 2 (d) shows a step of forming a rod-shaped temporary fixing connection body, in which a mirror-finished plate-like temporary fixing connection body 61A is cut along a cut surface 71 in a direction perpendicular to the temporary fixing surface. By cutting the Wollaston prism 1 in a rod-like form, a rod-shaped temporary-fixed connection body 70 is formed by cutting the Wollaston prism 1 in a rod shape. Since the rod-shaped temporary fixing joint 70 cut according to FIG. 2D is in a state where the individual Wollaston prisms are temporarily joined by the temporary fixing member 56, the rod-shaped temporary fixing is performed in the separation step shown in FIG. By removing the temporary fixing member 56 that constitutes the connecting body 70, it is separated into individual Wollaston prisms. When paraffin is used as the temporary fixing member 56, individual Wollaston prisms are obtained by placing the rod-shaped temporary fixing connecting member 70 on a hot plate (not shown) and dissolving and removing the paraffin. As described above, the Wollaston prism that can be manufactured by the method of the present invention includes not only a trapezoidal columnar crystal bonded with inclined surfaces but also a triangular prism crystal bonded with inclined surfaces. It is a thing. As shown in FIG. 3A, by joining the beam splitter 10 to one main surface of each of the obtained Wollaston prisms 1, it is possible to use the beam splitter 10 for the application shown in FIG. In addition,
In the case of manufacturing an optical device having the structure shown in FIG. 3 (a), after the mirror-finished thin temporary plate-like joint 61A obtained by the process of FIG. A plate-like connected body 80 of the beam splitter as shown in FIG. 3B is fixed by an adhesive and further cut along a cut surface 81 at a predetermined pitch in FIG. 82 is formed. Thereafter, the temporary fixing member 56 is removed by heating on a hot plate, whereby the optical device can be divided into individual optical devices as shown in FIG.
According to this method, it is apparent that mass productivity can be improved as compared with a method of joining a Wollaston prism as a small piece and a beam splitter as a piece.

[0011]

According to the present invention, the conventional complicated manufacturing method, in which a crystal having an optical axis is formed into a required shape by grinding and polishing and then joined, is greatly improved to increase productivity and increase cost. It is possible to provide a method of manufacturing a Wollaston prism that is downed. That is, a first substrate in the form of a rectangular flat plate having a crystal plate whose optical axis is parallel to the main surface of the crystal plate;
The upper and lower main surfaces of a rectangular flat plate-shaped second substrate made of a crystal plate having an optical axis having a predetermined inclination angle θ with respect to the main surface of the crystal plate are mirror-finished, and then the second substrate is placed on a horizontal plane. And the first substrate are laminated alternately and with the same opening, and the surface connecting the side edges of the laminated substrates is at a required inclination angle with respect to the horizontal plane, that is, 90 degrees-(second The multi-stage lamination is performed by shifting the surface direction in a stepwise manner so as to be inclined by the inclination angle θ) of the optical axis of the substrate, and the substrates are bonded together. Since a procedure such as forming a plurality of plate-shaped divided laminates by cutting at a predetermined plane direction pitch was used,
In order to manufacture individual pieces, a large amount of Wollaston prisms can be manufactured with good yield without individually grinding and polishing microscopic crystals.

[Brief description of the drawings]

FIGS. 1A to 1C are process diagrams for explaining a method for manufacturing a Wollaston prism of the present invention.

FIGS. 2A to 2E are process diagrams for explaining a method for manufacturing a Wollaston prism of the present invention.

FIGS. 3 (a) to 3 (d) are explanatory views of steps for manufacturing another optical device using the Wollaston prism of the present invention.

FIG. 4 is a hexahedral view showing a configuration of an example of a Wollaston prism.

FIG. 5 is a view showing an example of use of the Wollaston prism of FIG. 4;

6 (a) to 6 (c) are explanatory views of a conventional Wollaston prism manufacturing method.

[Explanation of symbols]

1 Wollaston prism, 2, 3 crystal, 10 beam splitter, 11 polarization splitting film, 20 pedestal, 21
Crystal, 30 first substrate, 30a crystal plate (crystal), 31 second substrate, 31a crystal plate (crystal),
35 jig, 36 adhesive, 40 laminated body, 45 cut surface, 50 divided laminated body, 51 cutting line (cut surface), 55
Temporary fixing laminate, 56 Temporary fixing material, 57 jig, 60
Cutting surface, 61 Plate-shaped temporary connection, 61A Plate-shaped temporary connection, 65 Cutting surface, 70 Bar-shaped temporary connection, 71
Cut surface, 80 plate-like connected body, 81 cut surface, 82 connected body.

Claims (5)

[Claims] 1. A trapezoidal or triangular prism made of a crystal having an optical axis and having a rectangular front face formed into a rectangular hexahedron by joining inclined surfaces of two trapezoidal or triangular prisms having different optical axis directions. In a method of manufacturing a Wollaston prism, a first substrate having a rectangular flat plate having an optical axis parallel to a main surface of a crystal plate and a predetermined inclination angle θ with respect to the main surface of the crystal plate are provided. Rectangular flat plate made of a crystal plate having
A first mirror-finish processing step of mirror-finishing the respective upper and lower principal surfaces of the substrate, and laminating the second substrate and the first substrate on a horizontal plane alternately and in parallel with each other, and each of the laminated substrates The surface connecting the side edges of the angle with respect to the horizontal plane is a required inclination angle, that is, 90 degrees.
A multi-layer stacking step in which the plane position is shifted in a stepwise manner so as to be inclined by (the tilt angle θ of the optical axis of the second substrate), and a laminate forming step of bonding between the substrates; Forming a plurality of plate-shaped divided laminates by cutting the formed laminate at a predetermined pitch along a cutting surface along the required inclination angle; and forming the divided laminate by the divided laminate formation step After laminating the plurality of divided laminated bodies in an aligned state in which the ends are aligned, a temporarily fixed laminated body forming step of forming a temporarily fixed laminated body by temporarily fixing each divided laminated body with a temporary fixing material, By cutting the temporary fixing laminate formed in the temporary fixing laminate forming step at a predetermined pitch along a direction orthogonal to the cut surface, a trapezoidal columnar first substrate portion and a second substrate portion are formed. On an inclined surface A plate-shaped temporary fixing joint forming step of forming a plate-like temporary fixing connecting body in which the united quadrangular prisms are connected in a plate shape; and a second mirror surface for mirror-finishing both upper and lower surfaces of the plate-like temporary fixing connecting body. A rod-shaped temporary fixing connection in which the Wollaston prism is temporarily connected in a rod shape by cutting the plate-shaped temporary fixing connection body having undergone the mirror finishing at a predetermined pitch along a direction orthogonal to the temporary fixing surface. A wollast comprising the steps of: forming a rod-shaped temporarily connected body that forms a body; and separating the individual Wollaston prisms by removing the temporary fixing material that constitutes the rod-shaped temporarily connected body. Manufacturing method of ton prism. 2. An anti-reflection film or / and / or a main surface of the first substrate and the second substrate after the first mirror finishing step.
And forming a matching film.
A method for manufacturing the Wollaston prism described in the above. 3. An anti-reflection film or / and / or a main surface of the first substrate and the second substrate after the second mirror finishing step.
And forming a matching film.
Or the method for manufacturing a Wollaston prism according to 2. 4. The method of manufacturing a Wollaston prism according to claim 1, wherein paraffin is used as the temporary fixing member. 5. The method according to claim 1, wherein an acute angle portion of an edge of the divided laminated body is cut off in advance.
A method for manufacturing the Wollaston prism described in the above.