JP2003302526A - Method for fabricating polarized beam splitter and the polarized beam splitter, hologram laser unit, and optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fabricating method which lowers the cost of a polarized beam splitter by improving the yield and by which the polarized beam splitter with high reliability can be fabricated. <P>SOLUTION: In the method for fabricating the polarized beam splitter consisting of a fabricating process of separating a plurality of polarized beam splitter formed of an optically anisotropic film 23 having diffraction gratings in an uneven shape on an optically transparent substrate wafer 22, an ordinary or extraordinary light-beam direction of the optically anisotropic film is detected in a process of forming the diffraction gratings after the optically anisotropic film 23 is stuck on the optically transparent substrate wafer 22. Further, the optically anisotropic film 23 on the optically transparent substrate wafer 22 has an orientation flat showing one of the ordinary and extraordinary light-beam directions. <P>COPYRIGHT: (C)2004,JPO

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 element, a polarization separation element, a hologram laser unit, and an optical pickup.

[0002]

2. Description of the Related Art Optical pickups for recording, reproducing or erasing information on an optical information recording medium (for example, an optical disc) are currently being demanded for miniaturization, cost reduction and high performance. Above all, the polarization separation element used for the optical pickup has been expected. The polarization separation element plays a role of totally transmitting the emitted light from the laser unit provided with the semiconductor laser element and the light receiving element, diffracting the reflected light from the optical disk, and receiving the light by the light receiving element of the laser unit. Up to now, various proposals have been made for the polarization separation element (for example, Japanese Patent Laid-Open No. 2000-751).
39, JP 2001-66428 A, etc.). Here, FIG. 1 is a cross-sectional view showing a configuration example of the polarization separation element 1. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). In the configuration of FIG. 1, a lower transparent substrate 3, an adhesive layer (A) 4, an optically anisotropic material 5 such as an organic birefringent film, an adhesive layer (B) 6, and an upper transparent substrate 7 are arranged from the bottom. The organic birefringent film 7 is provided with the concave-convex diffraction grating 2, and the groove is filled with the adhesive layer (B) 6. The lower transparent substrate 3 and the upper transparent substrate 7 are optically transparent.

FIG. 2 is a structural explanatory view showing an example of a hologram laser unit using a polarization separating element. FIG. 2A shows a state in which the polarization separating element 1 is mounted on a cap 9 with an adhesive 8. Is a perspective view of a main part of FIG.
A semiconductor laser 11 is mounted on a stem 13 having leads 14.
2 is a schematic configuration diagram of a hologram laser unit in which a light receiving element 12 is formed and a polarization separation element 1 is arranged on a cap 9. FIG. Incident light from the semiconductor laser 11 light source enters the polarization separation element 1 from the lower surface. The polarization direction of the reflected light from the optical disk is rotated 90 ° by the λ / 4 plate 10,
The diffraction grating portion 2 of the polarization separation element 1 is different depending on the polarization component.
(See FIG. 1) The extraordinary ray is separated, and the light receiving element 12 receives the light and detects the signal.

As a method for manufacturing a polarization separation element, usually,
Since the size of the polarization beam splitting element 1 is about several millimeters, several tens to several hundreds of diffraction gratings are formed in an array on an organic birefringent film adhered to a transparent substrate having a diameter of 4 to 8 inches. There is a method of taking out each polarization separation element by dicing. Further, an optically anisotropic film 5 such as an organic birefringent film is attached on the lower transparent substrate 3, a diffraction grating 2 is formed on the surface by etching, and an upper transparent substrate 7 is attached, and then, as shown in FIG. A plurality of polarization separation elements 15 made of wafers are cut vertically and horizontally at regular intervals by dicing as shown in (a schematic view of cutting of the polarization separation elements 15 made of wafers from directly above). A method of manufacturing the separation element chip 1 and taking out each chip is disclosed in JP-A-2000-75130 and JP-A-2001-664.
No. 28 publication is proposed as an example.

A method of bonding two plate-like substances such as substrates has been researched and developed for a bonded optical information recording medium (optical disk). The manufacturing method of them is shown in FIG.
It will be described with reference to FIG. FIG. 4 shows a spin table 17 having alignment pins 16, a lower substrate (hereinafter referred to as a first substrate 18) at the time of bonding, and an upper substrate (hereinafter referred to as a second substrate 19) at the time of bonding. It is a schematic perspective view of showing. Usually, in manufacturing an optical disc, the first substrate 18 and the second substrate 19 are plate-shaped. In addition, FIG.
It is explanatory drawing of the method of sticking the 2nd board | substrate 19 to the 1st board | substrate 18. FIG.

First, as shown in FIG. 5A, the first substrate 18 is placed on the spin table 17 having the alignment pins 16. After that, the adhesive 20 is applied on the first substrate 18, and the spin table is rotated to make the adhesive film thickness constant. FIG. 5B is a diagram showing a state where the adhesive 20 has a constant film thickness. Then, as shown in FIG. 5C, the second substrate 19 is placed on the adhesive 20. When an ultraviolet curable resin is used as the adhesive 20, the adhesive 20 is cured by irradiating ultraviolet rays (UV light) through the second substrate 19. In the method for producing an optical disk, these methods are further improved to reduce the bubbles of the adhesive (for example, JP-A-11-316982 and JP-A-9-9898).
No. 231626, Japanese Unexamined Patent Publication No. 5-20713)
Have been published.

In the method of manufacturing the polarization separation element 1, in the step of attaching an optically anisotropic film such as an organic birefringent film on the lower transparent substrate wafer, a method using a spin coat method similar to the method of manufacturing an optical disk is used. is there. The manufacturing method thereof will be described with reference to FIGS. FIG. 6 is a schematic perspective view showing a spin table 21 having no alignment pins, an optically transparent lower substrate wafer 22, and an optically anisotropic film 23 such as a birefringent film. Further, FIG. 7 is an explanatory diagram of a step of adhering an optically anisotropic film such as an organic birefringent film on a transparent substrate wafer.

First, as shown in FIG. 7A, an optically transparent lower substrate wafer 22 is set on a spin table 21 having no alignment pins. Thereafter, the adhesive 20 is applied to the optically transparent lower substrate wafer 22 and the spin table is rotated to make the adhesive film thickness constant. FIG. 7B is a diagram showing a state where the adhesive 20 has a constant film thickness. Then, as shown in FIG. 7C, the optically anisotropic film 23 is placed on the adhesive 20. When an ultraviolet curable resin is used as the adhesive 20, the adhesive 20 is irradiated with ultraviolet rays (UV light) through the optically anisotropic film 23.
Cure. In this step, no mark serving as the center of rotation is provided on the optically anisotropic film 23, and the optically anisotropic film 23 is not fixed. Therefore, the following two problems occur.

The first problem is that when the spin table 21 is rotated, the center of the optically anisotropic film 23 deviates from the center of rotation of the spin table. Generally, a mounting device is used to place the optically anisotropic film 23 on the optically transparent lower substrate wafer 22 coated with the adhesive 20, but the optical anisotropy is set at the rotation center of the spin table 21. Accurate alignment of the center of the film 23 is often difficult in terms of mechanical accuracy of the mounting device. When such a problem arises, in lithography and dry etching in the process of forming a diffraction grating, conveyance in the apparatus or between processes is often performed by clamping the side surface of the substrate, and thus the transparent substrate to the optically anisotropic film 23. If it sticks out, it becomes difficult to carry it, leading to a problem that a diffraction grating cannot be formed. The second problem is that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the optically anisotropic film 23 indicating the ordinary ray direction (or extraordinary ray direction) do not match.

An optically anisotropic film such as a birefringent film which constitutes a polarization beam splitting element is characterized by having two refractive indexes which are different depending on the direction, that is, the refractive index in the ordinary ray direction and the refractive index in the extraordinary ray direction. For this reason, in lithography and dry etching in the step of forming the diffraction grating, unless the directions of the ordinary ray and the extraordinary ray of the optically anisotropic film are clarified with appropriate accuracy, the polarization separation element cannot be produced with good yield. Therefore, in the method of manufacturing a polarization separation element, it is necessary to develop a method of manufacturing a polarization separation element including a step of clarifying the refractive index direction of an optically anisotropic film that can solve the above problems. In addition, it is necessary to use a transparent substrate that solves the above problems in a polarization separation element manufacturing process and to develop a method for manufacturing such a transparent substrate.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the invention according to claim 1 improves the yield of the polarization beam splitting element to reduce the cost and the polarization of high reliability. It is an object of the present invention to provide a method for manufacturing a polarization separation element that can manufacture a separation element.
In addition to the above object, the invention according to claim 2 provides a method for producing a polarization separation element, in which a polarization separation element is produced on a wafer and then separated into respective elements, wherein an optically anisotropic film on an optically transparent substrate wafer. Has an orientation flat indicating either the ordinary ray direction or the extraordinary ray direction, thereby clarifying the ordinary ray direction or the extraordinary ray direction, facilitating the subsequent steps, improving the yield, and depolarizing the light. The purpose is to lower the cost of. Further, in addition to the above objects, the invention according to claims 3 to 11 is such that one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film is substantially in the same direction as the orientation flat direction of the optically transparent substrate wafer. By using an optically transparent substrate wafer to which an optically anisotropic film is attached so as to achieve the following, it is an object to produce a highly reliable polarized light separation element with high yield. In addition to the above object, the invention according to claim 12 mainly aims to enhance the reliability of the element. In addition to the above objects, the invention according to claims 13 and 14 aims at producing a device with a high yield and increasing the reliability of the device in the method for producing a polarization separation device. In order to achieve the object of the invention according to claim 2, the invention according to claim 15 has one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film and the orientation flat direction of the optically transparent substrate wafer. It is an object of the present invention to improve the yield of the polarization separation element by producing and using a substrate having the same direction. Claim 16
In addition to the above-mentioned object, an object of the invention is to prevent generation of scratches or adhesion of foreign matter on the optically anisotropic film in the process of manufacturing the polarization separation element. According to a seventeenth aspect of the invention, in addition to the above-mentioned object, the production of the polarization separation element is facilitated,
The purpose is also to lower the cost of materials. Claim 18
In addition to the above object, the invention according to (1) aims to protect the optically anisotropic film and mainly improve the reliability of the device. In addition to the above object, the invention according to claim 19 aims to improve the degree of polarization separation of the polarization separation element. In addition to the above-mentioned object, the invention according to claim 20 is to manufacture a polarization beam splitting element having improved transmittance. In addition to the above object, the invention according to claim 21 aims at producing a highly reliable polarization separation element with good tact. It is an object of the invention according to claim 22 to provide a polarization separating element which is low in cost and high in reliability. An object of the invention of claim 23 is to manufacture a hologram laser unit having improved reliability. An object of the invention according to claim 24 is to provide an optical pickup having improved reliability.

[0012]

As means for achieving the above object, the invention according to claim 1 comprises a plurality of optically anisotropic films having concave and convex diffraction gratings on an optically transparent substrate wafer. In a method of manufacturing a polarization separation element comprising a step of separating the polarization separation element into each element, in the step of forming a diffraction grating after attaching the optically anisotropic film to the optically transparent substrate wafer, It is characterized in that the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected.

According to a second aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the first aspect, the optically anisotropic film on the optically transparent substrate wafer is usually the optically anisotropic film. It is characterized by having an orientation flat indicating either the ray direction or the extraordinary ray direction. The invention according to claim 3 is the method for producing a polarization beam splitting device according to claim 1 or 2, wherein the optical anisotropic film has one of an ordinary ray direction and an extraordinary ray direction, and the optically transparent film. It is characterized in that an optically transparent substrate wafer to which an optically anisotropic film is attached is used so that the orientation flat directions of the substrate wafer are substantially the same.

According to a fourth aspect of the present invention, in the method of manufacturing a polarization beam splitting element according to the first, second or third aspect, the optically transparent substrate wafer having the optically anisotropic film attached thereto is the optically transparent substrate. One of the ordinary ray direction and the extraordinary ray direction of the anisotropic film and the orientation flat direction of the optically transparent substrate wafer are parallel to each other with an accuracy of 2 ° or less. Further, the invention according to claim 5 is the method for producing a polarization beam splitting element according to any one of claims 1 to 4, wherein detection of an ordinary ray direction or an extraordinary ray direction of the optically anisotropic film is performed. It is characterized in that it is detected from an angle deviation from the orientation flat direction of the optically transparent substrate wafer.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a polarization beam splitting element according to any one of the first to fifth aspects,
Detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film on the optically transparent substrate wafer is one of the steps of forming a diffraction grating during the lithography step, before the step, and during the transportation to the step. The feature is to do either. The invention according to claim 7 is the method for manufacturing a polarization separation element according to any one of claims 1 to 6,
The detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed by using an exposure device or a reduction projection exposure device.

The invention according to claim 8 is a polarization separation device comprising a manufacturing process for separating a plurality of polarization separation devices, each of which is composed of an optically anisotropic film having an uneven diffraction grating on an optically transparent substrate wafer, into respective devices. In the device manufacturing method, the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected before the optically anisotropic film is attached to the optically transparent substrate wafer. In addition, claim 9
The invention according to claim 8 is the method for producing a polarization separation element according to claim 8, wherein the optically anisotropic film has an orientation flat indicating one of the ordinary ray direction and the extraordinary ray direction. There is.

According to a tenth aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the eighth or ninth aspect, the optical anisotropic film is optically detected after detecting one of the ordinary ray direction and the extraordinary ray direction. The anisotropic film is rotated, and then the optically anisotropic film is attached to the optically transparent substrate wafer. The invention according to claim 11 is the method for producing a polarization separation element according to claim 8, 9 or 10, wherein the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed by an optically transparent substrate. The feature is that it is detected from an angle deviation from the orientation flat direction of the wafer.

The invention according to claim 12 is defined by claims 1 to 11.
In the method for manufacturing a polarization beam splitting element according to any one of items 1, the optically transparent substrate wafer to which the optically anisotropic film is attached is adhered to form an adhesive layer having a substantially constant thickness. It is characterized by that. In addition, claim 13
The invention according to claim 1 is the method for manufacturing a polarization beam splitting element according to any one of claims 1 to 12, wherein the optically transparent substrate wafer to which the optically anisotropic film is adhered is rotated by a spin table. It is characterized by being manufactured by adjusting the adhesive film thickness.

The invention according to claim 14 relates to claims 1 to 13.
In the method for producing a polarization beam splitting element according to any one of the items, as a step of producing the optically transparent substrate wafer to which the optically anisotropic film is attached, an adhesive applied on the optically transparent substrate wafer is used. The method is characterized in that a step of rotating the spin table again to adjust the thickness of the adhesive to a constant value is provided after setting the film thickness to a constant value and disposing the optically anisotropic film thereon. The invention according to claim 15 is the claim 1
In the method for manufacturing a polarization separation element according to any one of 1 to 14, the orientation flat of the optically transparent substrate wafer is shown as a step of manufacturing the optically transparent substrate wafer to which the optically anisotropic film is attached. It is characterized in that a part or all of the line segment portion and a position of the line segment portion of the optically anisotropic film are aligned with each other.

The invention of claim 16 relates to claims 1 to 15.
In the method for producing a polarization beam splitting element according to any one of items 1 to 3, an optically anisotropic film having a separable protective film attached thereto is used as the optically anisotropic film. The invention according to claim 17 is the invention according to claims 1 to 16.
In the method for producing a polarization beam splitting element according to any one of the above items, an organic birefringent film is used as the optically anisotropic film.

The invention of claim 18 relates to claims 1 to 17.
In the method for producing a polarization beam splitting element according to any one of items 1, the polarization beam splitting element includes an optically transparent lower substrate, a lower adhesive layer (adhesive layer A), an optically anisotropic film, and an upper adhesive layer (adhesive). Layer B), an optically transparent upper substrate, and one of the optically transparent lower substrate or the optically transparent upper substrate is the optically transparent substrate wafer described above. The invention according to claim 19 is the method for producing a polarization separation element according to claim 18, wherein one of the refractive index in the ordinary ray direction and the extraordinary ray direction in the optically anisotropic film and its optical difference. The refractive index of the adhesive layer B filling the diffraction grating formed in the isotropic film and the refractive index of the adhesive layer A of the optically anisotropic material on the side where the diffraction grating is not formed are substantially the same. There is.

According to a twentieth aspect of the present invention, in the method of manufacturing a polarization separation element according to the eighteenth or nineteenth aspect, an antireflection film is provided on at least one of the lower surface of the optically transparent lower substrate and the upper surface of the optically transparent upper substrate. It is characterized by using an optically transparent substrate provided. In addition, claim 21
The invention according to claim 1 is the method for producing a polarization beam splitting element according to any one of claims 1 to 20, wherein an adhesive layer in the polarization beam splitting element according to any one of claims 1 to 17, or 18 20. As an adhesive used for producing the adhesive layers A and B in the polarization beam splitting element according to any one of 20 to 20, an epoxy adhesive, an acrylic adhesive or a rubber which is photosensitive and has a large elastic force. It is characterized by using a system adhesive.

The invention according to claim 22 is a polarization beam splitting element having a structure in which an optically anisotropic film having an uneven diffraction grating is provided on an optically transparent substrate. It is characterized in that it is manufactured by using the method for manufacturing a polarization separation element described in No. 3. The invention according to claim 23 is a hologram laser unit in which a polarization separation element is integrated with a laser unit having a semiconductor laser and a light receiving element, and is manufactured using the polarization separation element according to claim 22. There is. Further claim 2
The invention according to 4 is for recording information on an optical information recording medium,
An optical pickup for reproducing or erasing is characterized by being manufactured by using the polarization separation element according to claim 22 or the hologram laser unit according to claim 23.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiments shown in the drawings.
The inventions according to 17 to 22 will be described. In the second embodiment, the invention according to claims 1 to 4, 12 and 17 to 22 will be described. In the third embodiment, the invention according to claims 1 to 7, 12 to 14, and 16 to 22 will be described. In the fourth embodiment, claims 1 to 4, 1
The invention according to 2-14 and 16-22 will be described. Example 5
Now, the inventions according to claims 1 to 7, 12 to 14, and 16 to 24 will be described. In Example 6, claims 1 to 4, 12 and 2
The invention according to No. 2 will be described. In Example 7, claims 8 to 2
The invention according to No. 4 will be described. In Example 8, claims 1 to
Inventions relating to Nos. 4, 12 to 24 will be described. In Example 9,
The invention according to claims 1 to 4 and 12 to 22 will be described.

[Embodiment 1] Claims 1-7, 12, 17-
21 is a sectional view of a polarization beam splitting element manufactured by carrying out the invention of No. 21. In the configuration of FIG. 1, the adhesive layer is 2
Since there are layers, they are distinguished by the symbols (A) and (B).
The configuration of FIG. 1 has an optically transparent lower substrate 3 (BK7,
Thickness: 1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02 m
m), the organic birefringent film 5 (refractive index 1.58 in the extraordinary ray direction,
Ordinary ray direction refractive index 1.67, thickness: 0.1 mm), adhesive layer (B) 6 (epoxy UV curable resin, refractive index 1.
58, thickness: 0.04 mm), optically transparent upper substrate 7
(BK7, thickness: 1.0 mm). Organic birefringent film 5
Is a concave and convex diffraction grating 2 (grating depth 4 μm, pitch 2
μm, P polarized light transmittance about 98%, S polarized light transmittance about 1%, 1
Next diffraction light diffraction efficiency is about 40%), and the groove is filled with the adhesive layer (B) 6. This Figure 1
The polarization separation element having the structure shown in FIG. 1 operates as described in the related art. Hereinafter, a procedure for manufacturing the polarization beam splitting element having the structure shown in FIG. 1 will be described with reference to FIGS.

(1). A substrate in which an organic birefringent film 23 was attached on an optically transparent lower substrate wafer (BK7 glass substrate) 22 as shown in FIG. 8A was prepared. The optically transparent lower substrate wafer 22 has a diameter of 100 mm and a thickness of 1.0 mm, and an orientation flat is formed at the end. Further, an antireflection film is applied to the surface of the optically transparent lower substrate wafer 22 on the side where the organic birefringent film 23 is not attached. Organic birefringent film 23
Has a diameter of 90 mm and a thickness of 0.1 mm, and an orientation flat indicating the extraordinary ray direction is formed at the end. The lower surfaces of the optically transparent lower substrate wafer 22 and the organic birefringent film 23 are adhered to each other with an epoxy ultraviolet curing resin of the same quality as the adhesive layer (A) 4, and the adhesive layer (A) 4
Has a thickness of 0.02 mm. At this stage, it is not possible to grasp how much the orientation flat direction of the optically transparent lower substrate wafer 22 and the orientation flat direction of the organic birefringent film 23 deviate from each other.

(2). Optically transparent lower substrate wafer 22
The surface of the upper organic birefringent film 23 was washed. (3). Apply a positive resist on the organic birefringent film 23,
Prebaking was performed at 90 ° C. for 30 minutes. (4). The optically transparent lower substrate wafer 22 having the organic birefringent film 23 attached thereto is subjected to a reduction projection exposure apparatus (NA = 0.
45, σ = 0.6, wavelength; i line) mounted on the stage,
It was fixed by vacuum adsorption. The organic birefringent film 23 is obtained from the image captured by the CCD camera attached to the reduction projection exposure apparatus.
It was confirmed that the direction of the orientation flat of 1 was shifted by 2 ° with respect to the direction of the orientation flat of the optically transparent lower substrate wafer 22. By rotating the optically transparent lower substrate wafer 22 by 2 °, 2 °
The angle deviation was corrected, and the line-and-space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 were matched.

(5). Exposure is performed using a reticle having a 1.5 μm line and space pattern with 1000 cycles, and development is performed using a developing solution NMD-3, and then 1
Post-baking was performed at 00 ° C. for 30 minutes to complete a periodic resist pattern. (6). Aluminum (Al) was vapor-deposited on the resist pattern by a sputtering method, and then the resist was dissolved by using acetone to lift off the Al to complete an Al pattern in which the resist pattern was inverted. After that, ECR (Electoron Cyclotron Resonanc
e) The organic birefringent film was etched to a depth of 4 μm using the above Al pattern as a metal mask in an etching gas atmosphere containing oxygen gas as a main component using an etching apparatus. (7). The Al pattern was removed using a phosphoric acid-based Al etching solution to complete a diffraction grating having irregularities of 1000 cycles. FIG. 8B is a top view schematically showing a state in which a diffraction grating is formed on the organic birefringent film 23 on the optically transparent lower substrate wafer 22.

(8). Spacers (5 mm on each side, a metal piece having a thickness of 40 μm) 26 are attached to the end portions on the organic birefringent film 23.
It is installed in a place, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center, and an optically transparent upper substrate wafer 25 is
The surface provided with the antireflection film was placed on the upper side. Figure 9
(A) is an organic transparent birefringent film 23 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21, with an epoxy ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged.

(9). Optically transparent lower substrate wafer 22
Optically transparent upper substrate wafer 25 while maintaining parallel to
Was continuously pressed from above with a constant pressure, and when the optically transparent upper substrate wafer 25 was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24. FIG. 9B is a perspective view showing how UV light is emitted. (10). The substrate prepared in the previous step was fixed to a dicing tape, and the line spacing was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were as shown in FIG. Each 12 lines were cut. (11). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

Thus, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.

In the method of manufacturing the polarization beam splitting element of Example 1,
Compared with the conventional example, the direction of the orientation flat of the optically transparent lower substrate wafer 22 and the organic birefringent film 23.
After correcting the angle deviation of the orientation flat of, the lithography process of forming the diffraction grating is performed. After that, the yield of the diffraction grating is improved by correcting the angular deviation so that the line and space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 in the lithography process are matched. Therefore, it is possible to improve the yield of the polarization separation element, reduce the cost, and provide a highly reliable element.

The polarization separation element manufactured by such a method can be manufactured with good tact because it has a step of detecting an angular deviation, and the polarization separation element manufactured can be manufactured by using an adhesive layer (A Since the film thickness of 4) is almost constant, reliability as an element is high, and variation in quality between elements is small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%. The refractive index in the extraordinary ray direction of the organic birefringent film 5 and the refractive index of the adhesive layer (B) 6 are 1.58, which are almost the same value, and the diffraction efficiency is also high. Further adhesive layer (A)
4 has the same refractive index of 1.58, the adhesive layer (A) 4
The adhesive layer (B) 6 and the adhesive layer (B) 6 can use the same adhesive, and the cost can be reduced. Further, as the adhesive layer (A) 4 and the adhesive layer (B) 6, an epoxy-based ultraviolet curable resin having a large elastic force is used, and a defect such as peeling of the organic birefringent film 5 is unlikely to occur, and polarization separation is performed. The element becomes a highly reliable element.

[Embodiment 2] Claims 1-4, 12, 17-
21 is a sectional view of a polarization beam splitting element manufactured by carrying out the invention of No. 21. In the configuration of FIG. 1, the adhesive layer is 2
Since there are layers, they are distinguished by the symbols (A) and (B).
The configuration of FIG. 1 has an optically transparent lower substrate 3 (BK7,
Thickness: 1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02 m
m), the organic birefringent film 5 (refractive index 1.58 in the extraordinary ray direction,
Ordinary ray direction refractive index 1.67, thickness: 0.1 mm), adhesive layer (B) 6 (epoxy UV curable resin, refractive index 1.
58, thickness: 0.04 mm), optically transparent upper substrate 7
(BK7, thickness: 1.0 mm). Organic birefringent film 5
Is a concave and convex diffraction grating 2 (grating depth 4 μm, pitch 2
μm, P polarized light transmittance about 98%, S polarized light transmittance about 1%, 1
Next diffraction light diffraction efficiency is about 40%), and the groove is filled with the adhesive layer (B) 6. This Figure 1
The polarization separation element having the structure shown in FIG. 1 operates as described in the related art. The procedure for producing the polarization beam splitting element having the structure shown in FIG. 1 will be described below with reference to FIG.

(1). A substrate in which an organic birefringent film 23 was attached on an optically transparent lower substrate wafer (BK7 glass substrate) 22 as shown in FIG. 10A was prepared. The optically transparent lower substrate wafer 22 has a diameter of 100 mm and a thickness of 1.0 mm, and an orientation flat is formed at the end. Further, an antireflection film is provided on the surface of the optically transparent lower substrate wafer on which the organic birefringent film 23 is not attached. Organic birefringent film 23
Has a diameter of 90 mm and a thickness of 0.1 mm, and an orientation flat indicating the extraordinary ray direction is formed at the end. The lower surfaces of the optically transparent lower substrate wafer 22 and the organic birefringent film 23 are adhered to each other with an epoxy ultraviolet curing resin of the same quality as the adhesive layer (A) 4, and the adhesive layer (A) 4
Has a thickness of 0.02 mm. In this embodiment, it was confirmed with a metallographic microscope equipped with a CCD camera that the orientation flat direction of the optically transparent lower substrate wafer 22 and the orientation flat direction of the organic birefringent film 23 were within 1 °. There is.

(2). After cleaning the surface of the organic birefringent film 23, a diffraction grating was formed by photolithography and dry etching. (3). Spacers (5 mm on a side, metal pieces having a thickness of 40 μm) 26 are installed at four locations on the end of the organic birefringent film 23, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center of the optically transparent upper substrate wafer 25. Was placed with the surface on which the antireflection film was applied facing upward. FIG. 10 (b) shows
On the organic birefringent film 23 adhered with the adhesive 20 on the optically transparent lower substrate wafer 22 placed on the spin table 21, the epoxy ultraviolet curable resin 24 is applied.
FIG. 8 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged via the above.

(4). Optically transparent lower substrate wafer 22
Optically transparent upper substrate wafer 25 while maintaining parallel to
Was continuously pressed from above with a constant pressure, and when the optically transparent upper substrate wafer 25 was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24. FIG. 10C is a perspective view showing how UV light is emitted. (5) The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, as shown in FIG. 3 (cutting viewed from directly above). 12 lines were cut vertically and horizontally. (6). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

Thus, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.

In the method of manufacturing the polarization beam splitting element of Example 1,
Compared with the conventional example, the direction of the orientation flat of the optically transparent lower substrate wafer 22 and the organic birefringent film 23.
Since the optically transparent lower substrate wafer 22 to which the organic birefringent film 23 is attached with an orientation flat direction of 1 ° or less is used, the organic birefringent film 23
A diffraction grating can be formed in accordance with the refractive index direction of, and the yield of the polarization separation element can be improved. The accuracy of measuring the refractive index of the organic birefringent film 23 used is about 1 °, and the orientation flat direction of the optically transparent lower substrate wafer 22 and the orientation flat direction of the organic birefringent film 23 are accurate within 2 °. It has been found that if an optically transparent lower substrate wafer 22 having a birefringent film 23 attached thereto is used, the yield exceeds about 90%. When the angle shift of 2 ° or more occurs, the yield decreases due to the decrease of the diffraction efficiency of the polarization separation element.

The polarization separation element manufactured by such a method mainly uses a substrate in which the orientation flats of the optically transparent lower substrate wafer 22 and the organic birefringent film 23 are matched, so that the yield is improved. Further, since the manufactured polarization separation element has a substantially uniform film thickness of the adhesive layer (A) 4, it has high reliability as an element, and variations in quality among the elements are small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%. The refractive index of the organic birefringent film 5 in the extraordinary ray direction and the refractive index of the adhesive layer (B) 6 are 1.5.
8, the value is almost the same, and the diffraction efficiency is also high. Further, since the adhesive layers (A) 4 have the same refractive index of 1,58, the adhesive layers (A) 4 and the adhesive layers (B) 6 can use the same kind of adhesive agent, which reduces the cost. It is possible.
Further, as the adhesive layer (A) 4 and the adhesive layer (B) 6, epoxy-based ultraviolet curable resin having high elasticity is used,
Problems such as peeling of the organic birefringent film 5 are unlikely to occur,
It becomes a highly reliable element as a polarization separation element.

[Embodiment 3] Claims 1 to 7, 12 to 14,
A cross-sectional view of a polarization beam splitting element manufactured by carrying out the invention according to 16 to 21 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). The configuration shown in FIG. 1 includes an optically transparent lower substrate 3 (B
K7, thickness: 1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02
mm), organic birefringent film 5 (refractive index in extraordinary ray direction 1.5)
8, ordinary ray direction refractive index 1.67, thickness: 0.1 mm),
The adhesive layer (B) 6 (epoxy-based ultraviolet curable resin, refractive index 1.58, thickness: 0.04 mm) and the optically transparent upper substrate 7 (BK7, thickness: 1.0 mm). The organic birefringent film 5 has an uneven diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%,
A first-order diffracted light diffraction efficiency of about 40%) is formed, and the groove is filled with the adhesive layer (B) 6. The polarization separation element having the configuration shown in FIG. 1 operates as described in the prior art. The procedure for manufacturing the polarization beam splitting element having the structure of FIG. 1 will be described below with reference to FIGS.

(1). Diameter 100 mm, thickness 1.0 m
m, optically transparent lower substrate wafer (BK7 glass substrate) with orientation flats formed at the edges
22 was placed on the spin table 21 of the spinner so that the center of the optically transparent lower substrate wafer 22 and the center of the spin table 21 were aligned with each other, and vacuum suction was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 11A is a diagram showing a state in which the optically transparent lower substrate wafer 22 is placed on the spin table 21 and vacuum suction is performed. (2). Epoxy UV curable resin is dropped as an adhesive on the optically transparent lower substrate wafer 22 and the whole substrate 7
The resin was rotated at 00 rpm to adjust the thickness of the epoxy UV curable resin to a constant film thickness.

(3). An organic birefringent film 23 having a diameter of 80 mm and a film thickness of 100 μm was prepared. FIG. 11B is a view of the optically transparent lower substrate wafer 22 and the birefringent film 23 having an orientation flat indicating the extraordinary ray direction, as viewed from directly above. The organic birefringent film 23 has protective films attached to both surfaces thereof, and an orientation flat indicating an extraordinary ray direction is formed at an end thereof. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. FIG. 11C shows an optically transparent lower substrate wafer 22.
FIG. 3 is a diagram in which an epoxy-based ultraviolet curable resin 20 is applied on a certain thickness and an organic birefringent film 23 is to be disposed thereon.

(4). An organic birefringent film 23 is arranged with the surface from which the protective film is peeled downward so that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flat of the birefringent film 23 are aligned with each other. 21 was rotated again. When the directions of the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 are deviated, the organic birefringent film 23 is rotated by using a fine needle so that these directions coincide with each other. It was

(5). The epoxy-based UV curable resin 20 was cured by irradiating it with UV light for several minutes with a high pressure mercury lamp. The epoxy-based UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using acetone. FIG. 11D is a perspective view in which the organic birefringent film 23 is placed on the optically transparent lower substrate wafer 22 and UV light is irradiated to cure the epoxy ultraviolet curable resin 20. In addition, FIG. 12A is a top view of the organic birefringent film 23 attached on the optically transparent lower substrate wafer.

(6). The protective film on the surface of the organic birefringent film 23 which was not peeled off was peeled off, and the surface was washed. (7). A positive resist was applied on the organic birefringent film 23 on the optically transparent lower substrate wafer 22 and prebaked at 90 ° C. for 30 minutes.

(8). The optically transparent lower substrate wafer 22 to which the organic birefringent film 23 is attached is attached to the stage of a reduction projection exposure apparatus (NA = 0.45, σ = 0.6, wavelength; i-line), and vacuum adsorption is performed. Fixed From the image obtained by the CCD camera attached to the reduction projection exposure apparatus, it was confirmed that the orientation flat direction of the organic birefringent film 23 was deviated from the orientation flat direction of the optically transparent lower substrate wafer 22 by 2 °. Then, by rotating the optically transparent lower substrate wafer 22 by 2 °, the angle deviation of 2 ° was corrected, and the line and space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 were matched.

(9). Exposure is performed using a reticle having a 1.5 μm line and space pattern with 1000 cycles, and development is performed using a developing solution NMD-3, and then 1
Post-baking was performed at 00 ° C. for 30 minutes to complete a periodic resist pattern. (10). Al was vapor-deposited on the resist pattern by a sputtering method, and then the resist was dissolved by using acetone to lift off the Al to complete an Al pattern in which the resist pattern was inverted. Then EC
The organic birefringent film was etched to a depth of 4 μm using the R pattern as a metal mask in an etching gas atmosphere containing oxygen gas as a main component. (11). The Al pattern was removed using a phosphoric acid-based Al etching solution to complete a diffraction grating having irregularities of 1000 cycles. FIG. 12B is a top view schematically showing a state where a diffraction grating is formed on the organic birefringent film 23 on the optically transparent lower substrate wafer 22.

(12). Spacers (5 mm on a side, metal pieces having a thickness of 40 μm) 26 are installed at four locations on the end of the organic birefringent film 23, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center of the optically transparent upper substrate wafer 25.
Was placed with the surface on which the antireflection film was applied facing upward. FIG. 13A shows an epoxy UV curable resin 24 on an organic birefringent film 23 attached by an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21. Optically transparent upper substrate wafer 2 through
5 is a front sectional view showing an example in which 5 is arranged. (13). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When it was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24.
FIG. 13B is a perspective view of irradiating UV light.

(14). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (15). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

Thus, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 23 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

In the method of manufacturing the polarization beam splitting element of Example 3,
How much the orientation flat of the organic birefringent film 23 deviates from the orientation flat of the optically transparent lower substrate wafer 22 was detected from the image obtained by the CCD camera attached to the reduction projection exposure apparatus. Thereafter, correction is performed so that the line and space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 in the lithography process are made to coincide with each other, whereby the yield of the diffraction grating formation is improved. Further, since the optically transparent lower substrate wafer 22 to which the organic birefringent film 23 is attached is manufactured by using the spin coat method, the error in the thickness of the adhesive layer is about 10% in the whole wafer. Also, by using an organic birefringent film with a protective film attached, scratches and foreign substances are hard to attach to the birefringent film in each process, and a substrate with improved quality is used as a substrate for manufacturing a polarization separation element. it can.

The polarization beam splitting element manufactured by such a method can be manufactured with good tact as compared with the conventional example.
In addition, since the manufactured polarization separation element has a substantially constant film thickness of the adhesive layer (A) 4, it has high reliability as an element,
Variations in quality between elements are also small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent substrate, the P polarized light transmittance is about 98%. The refractive index in the extraordinary ray direction of the organic birefringent film 5 and the refractive index of the adhesive layer (B) 6 are 1.58, which are almost the same value, and the diffraction efficiency is also high. Furthermore, since the refractive index of the adhesive layer (A) 4 is the same 1.58,
The adhesive layer (A) 4 and the adhesive layer (B) 6 can use the same type of adhesive agent, and the cost can be reduced. Further, as the adhesive layer (A) 4 and the adhesive layer (B) 6,
Since the epoxy-based ultraviolet curable resin having a large elastic force is used, the problem that the organic birefringent film 5 is peeled off hardly occurs, and it becomes a highly reliable element as a polarization separation element.

[Embodiment 4] Claims 1 to 4, 12 to 14,
A cross-sectional view of a polarization beam splitting element manufactured by carrying out the invention according to 16 to 21 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). The configuration shown in FIG. 1 includes an optically transparent lower substrate 3 (B
K7, thickness: 1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02
mm), organic birefringent film 5 (refractive index in extraordinary ray direction 1.5)
8, ordinary ray direction refractive index 1.67, thickness: 0.1 mm),
The adhesive layer (B) 6 (epoxy-based ultraviolet curable resin, refractive index 1.58, thickness: 0.04 mm) and the optically transparent upper substrate 7 (BK7, thickness: 1.0 mm). The organic birefringent film 5 has an uneven diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%,
A first-order diffracted light diffraction efficiency of about 40%) is formed, and the groove is filled with the adhesive layer (B) 6. The polarization separation element having the configuration shown in FIG. 1 operates as described in the prior art. The procedure for manufacturing the polarization beam splitting element having the structure of FIG. 1 will be described below with reference to FIGS.

(1). Diameter 100 mm, thickness 1.0 m
m, optically transparent lower substrate wafer (BK7 glass substrate) with orientation flats formed at the edges
22 was placed on the spin table 21 of the spinner so that the center of the optically transparent lower substrate wafer 22 and the center of the spin table 21 were aligned with each other, and vacuum suction was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 11A is a diagram showing a state in which the optically transparent lower substrate wafer 22 is placed on the spin table 21 and vacuum suction is performed. (2). Epoxy UV curable resin is dropped as an adhesive on the optically transparent lower substrate wafer 22 and the whole substrate 7
The resin was rotated at 00 rpm to adjust the thickness of the epoxy UV curable resin to a constant film thickness.

(3). An organic birefringent film 23 having a diameter of 80 mm and a film thickness of 100 μm was prepared. FIG. 11B is a view of the optically transparent lower substrate wafer 22 and the birefringent film 23 having an orientation flat indicating the extraordinary ray direction, as viewed from directly above. The organic birefringent film 23 has protective films attached to both surfaces thereof, and an orientation flat indicating an extraordinary ray direction is formed at an end thereof. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. FIG. 11C shows an optically transparent lower substrate wafer 22.
It is a figure which shows a mode that the epoxy-type ultraviolet curing resin 20 is apply | coated to a fixed film thickness on it, and the organic birefringent film | membrane 23 is about to be arrange | positioned on it.

(4). The organic birefringent film 23 is arranged with the surface from which the protective film is peeled downward, so that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 23 are aligned.
After sticking, the spin table 21 was rotated again. When the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 23 are deviated from each other, these directions are aligned with each other.
The organic birefringent film 25 was rotated using a fine needle. (5). The epoxy-based UV curable resin 20 was cured by irradiating it with UV light for several minutes with a high pressure mercury lamp. The epoxy-based UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using acetone. Figure 11
(D) is a perspective view showing a state in which the organic birefringent film 23 is placed on the optically transparent lower substrate wafer 22 and the epoxy ultraviolet curable resin 20 is cured by being irradiated with UV light. .

(6). Optically transparent lower substrate wafer 22 having organic birefringent film 23 attached (FIG. 12A)
Was observed with a metallographic microscope equipped with a CCD camera, and it was confirmed that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 were parallel to each other with an accuracy of 1 °. The thickness of the produced substrate was measured, and the thickness of the optically transparent lower substrate wafer 22 and the thickness of the organic birefringent film 23 were subtracted from the measured values to obtain the adhesive layer thickness.
Was 22 μm. (7). The protective film on the surface of the organic birefringent film 23 which was not peeled off was peeled off, and the surface was washed. (8). Organic birefringent film 23 attached to an optically transparent substrate
A diffraction grating was formed on the surface by photolithography and dry etching (FIG. 12B).

(9). Spacers (5 mm on each side, a metal piece having a thickness of 40 μm) 26 are attached to the end portions on the organic birefringent film 23.
It is installed in a place, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center, and an optically transparent upper substrate wafer 25 is
The surface provided with the antireflection film was placed on the upper side. FIG.
(A) is an organic transparent birefringent film 23 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21, with an epoxy ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged. (10). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When it was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24.
FIG. 13B is a perspective view showing how UV light is emitted.

(11). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (12). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

Thus, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 23 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

In the method of manufacturing the polarization separation element of Example 4,
An optically transparent lower substrate wafer was produced in which the organic birefringent film 23 was attached with an accuracy of 1 ° in the orientation flat direction of the optically transparent lower substrate wafer 22 and the orientation flat direction of the organic birefringent film 23.
The accuracy of measuring the refractive index of the organic birefringent film used is about 1 °, and the direction of the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 are within 2 °. Optically transparent lower substrate wafer 22 having a refraction film 23 attached
Yields have been found to exceed about 90%. When the angle shift of 2 ° or more occurs, the yield decreases due to the decrease of the diffraction efficiency of the polarization separation element. Since this substrate was manufactured by using the method of rotating the spin table to adjust the film thickness of the adhesive layer, the error of the film thickness of the adhesive layer is about 10% in the whole wafer. Also,
By using the organic birefringent film to which the protective film is attached, scratches and foreign substances are not easily attached to the organic birefringent film in each process, and a substrate with improved quality can be used as a substrate for manufacturing the polarization separation element. .

The polarization splitting element manufactured by such a method mainly utilizes the coincidence of the orientation flats of the optically transparent lower substrate wafer 22 and the organic birefringent film 23, so that it is more takt than the conventional example. It is possible to manufacture, and the manufactured polarization separation element has an adhesive layer (A) 4
Since the film thickness of is almost constant, the reliability as an element is high, and the variation in quality between elements is small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%.
The extraordinary ray direction refractive index of the organic birefringent film 5 and the adhesive layer (B) 6
Has a refractive index of 1.58, which is almost the same value and a high diffraction efficiency. Further, since the adhesive layers (A) 4 also have the same refractive index of 1.58, the adhesive layers (A) 4 and the adhesive layers (B) 6 can use the same type of adhesive agent, which reduces the cost. It is possible. Also, the adhesive layer (A) 4 and the adhesive layer (B)
As 6, an epoxy-based ultraviolet curable resin having a large elastic force is used, and a defect such as peeling of the organic birefringent film 5 is unlikely to occur, and a highly reliable element as a polarization separation element is obtained.

[Embodiment 5] Claims 1 to 7, 12 to 14,
A cross-sectional view of a polarization beam splitting element manufactured by carrying out the invention according to 16 to 21 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). The configuration shown in FIG. 1 includes an optically transparent lower substrate 3 (B
K7, thickness: 1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02
mm), organic birefringent film 5 (refractive index in extraordinary ray direction 1.5)
8, ordinary ray direction refractive index 1.67, thickness: 0.1 mm),
The adhesive layer (B) 6 (epoxy-based ultraviolet curable resin, refractive index 1.58, thickness: 0.04 mm) and the optically transparent upper substrate 7 (BK7, thickness: 1.0 mm). The organic birefringent film 5 has an uneven diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%,
A first-order diffracted light diffraction efficiency of about 40%) is formed, and the groove is filled with the adhesive layer (B) 6. The polarization separation element having the configuration shown in FIG. 1 operates as described in the prior art. The procedure for producing the polarization beam splitting element having the structure shown in FIG. 1 will be described below with reference to FIGS. FIG. 18 shows the configuration of a hologram laser unit and an optical pickup using the manufactured polarization separation element.

(1). An optically transparent lower substrate wafer (BK7 glass substrate) 22 having a diameter of 100 mm, a thickness of 1.0, and an orientation flat formed at the end is placed on the spin table 21 of the spinner, and the center of the optically transparent lower substrate wafer 22 is placed. And the spin table 21 were arranged so that their centers coincided with each other, and vacuum adsorption was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. In FIG. 14A, an optically transparent lower substrate wafer 22 is arranged on a spin table 21,
It is a figure which shows a mode that vacuum adsorption was performed. (2). Epoxy UV curable resin was dropped as an adhesive on the optically transparent lower substrate wafer 22, and the spin table 21 was rotated together with the substrate at 700 rpm to adjust the epoxy UV curable resin 20 to a constant thickness.

(3). An organic birefringent film 23 having a diameter of 80 mm and a film thickness of 100 μm was prepared. FIG. 14B is a view of the optically transparent lower substrate wafer 22 and the organic birefringent film 23 as seen from directly above. The organic birefringent film 23 has protective films attached to both surfaces. The shape is the same as the organic birefringent film 23 used in Examples 3 and 4. Therefore, the extraordinary ray direction of the birefringent film 23 is indicated by an orientation flat composed of line segments. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. 14
FIG. 3C is a diagram showing a state in which the epoxy-based ultraviolet curable resin 20 is applied to the optically transparent lower substrate wafer 22 to a constant film thickness, and the organic birefringent film 23 is being arranged thereon.

(4). The organic birefringent film 23 is arranged with the surface from which the protective film is peeled downward, so that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 23 are aligned.
After sticking, the spin table 21 was rotated again. When the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 23 are deviated from each other, these directions are aligned with each other.
The organic birefringent film 23 was rotated using a fine needle. Finally, as shown in FIG. 15A, the position was adjusted so that the orientation flat direction of the organic birefringent film 23 coincided with the orientation flat direction of the optically transparent lower substrate wafer 22.

(5). The epoxy-based UV curable resin 20 was cured by irradiating it with UV light for several minutes with a high pressure mercury lamp. The epoxy-based UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using acetone. FIG. 15B is a perspective view showing a state in which the organic birefringent film 23 is placed on the optically transparent lower substrate wafer 22 and the epoxy ultraviolet curable resin 20 is cured by being irradiated with UV light. Is. (6). The protective film on the surface of the organic birefringent film 23 which was not peeled off was peeled off, and the surface was washed. (7) A positive resist was applied on the organic birefringent film 23 on the optically transparent lower substrate wafer 22 and prebaked at 90 ° C. for 30 minutes.

(8). As shown in FIG. 16, an optically transparent lower substrate wafer 2 having an organic birefringent film 23 attached thereto.
2 reduction projection exposure device 27 (NA = 0.45, σ = 0.
6, the wavelength; i line) was placed on the wafer tray 28 connected in a belt manner and fixed. As the belt moves, the substrate on the wafer tray 28 also moves, and C
It was temporarily stopped at the position where the CD camera 29 was attached. FIG. 16 is a schematic configuration diagram of a wafer transfer path, a reduction projection exposure device 27, and a CCD camera 29. A wafer tray 28 for fixing a wafer is installed on the transfer path that moves in a belt type. (9). An image obtained by the CCD camera 29 confirmed that the orientation flat direction of the organic birefringent film 23 was deviated by 3 ° from the orientation flat direction of the optically transparent lower substrate wafer 22. Therefore, by rotating the wafer tray 28, the optically transparent lower substrate wafer 22 was rotated so that the angle deviation of 3 ° could be corrected. (10). By moving the belt again, the substrate on the wafer tray 28 was moved to the stage of the reduction projection exposure apparatus 27. In this state, the line and space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 are substantially coincident with each other.

(11). Exposure was performed using a reticle having a 1.5 μm line and space pattern with 1000 cycles. After that, the belt was moved and the exposed substrate was taken out. (12). Development was performed using the developing solution NMD-3, and then post-baking was performed at 100 ° C. for 30 minutes to complete a periodic resist pattern. (13). Al was vapor-deposited on the resist pattern by a sputtering method, and then the resist was dissolved by using acetone to lift off the Al to complete an Al pattern in which the resist pattern was inverted. Then ECR
The organic birefringent film was etched to a depth of 4 μm using the above Al pattern as a metal mask in an etching gas atmosphere containing oxygen gas as a main component using an etching apparatus. (14). The Al pattern was removed using a phosphoric acid-based Al etching solution to complete a diffraction grating having irregularities of 1000 cycles. FIG. 17A is a top view schematically showing a state in which a diffraction grating is formed on the organic birefringent film 23 on the optically transparent lower substrate wafer 22.

(15). Spacers (5 mm on a side, metal pieces having a thickness of 40 μm) 26 are installed at four locations on the end of the organic birefringent film 23, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center of the optically transparent upper substrate wafer 25.
Was placed with the surface on which the antireflection film was applied facing upward. FIG. 17B shows an epoxy-based ultraviolet curable resin 24 on an organic birefringent film 23 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21. Optically transparent upper substrate wafer 2 through
5 is a front sectional view showing an example in which 5 is arranged. (16). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When it was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24.
FIG. 17C is a perspective view showing how UV light is emitted.

(17). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (18). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

Thus, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the birefringent film 23 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

(19). After that, a semiconductor laser 11 and a light receiving element (photodiode) 12 have a common stem by using the polarization separating element 1 having the configuration shown in FIG. 1 manufactured by the above manufacturing method and using a hologram mounting device provided with a gripping hand. The polarization separation element 1 was placed at the mounting position of the cap 9 of the laser unit mounted above, and the position was adjusted horizontally. (20). As shown in FIGS. 2 (a) and 2 (b), acrylic UV curable resin 8 is applied to the lower four corners of the side surface of the polarization separation element 1 by using a dispenser, and is irradiated with ultraviolet rays to be fixed to fix the hologram. A laser unit was produced. (21). Next, as shown in FIG. 18, by using the hologram laser unit, the λ / 4 plate 10, the optically adjusted collimator lens 30, and the objective lens 31, recording, reproduction, or erasing of information on the optical disc 32 is performed. An optical pickup optical system is formed.

In the method of manufacturing the polarization beam splitting element of Example 5,
In the lithography process, the angle deviation between the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23
This is carried out during transportation to the reduction projection exposure apparatus. for that reason,
Exposure can be performed in a state where the line and space pattern of the reticle and the extraordinary ray direction of the organic birefringent film 23 substantially coincide with each other, which improves the yield of the polarization separation element. In addition, since this substrate was manufactured by utilizing the rotation of the spin table 21 while keeping the adhesive film thickness constant, the error in the adhesive layer film thickness of the entire wafer is about 10%. Further, by using the birefringent film to which the protective film is attached, scratches and foreign substances are hard to be attached to the birefringent film in each step, and a substrate of improved quality can be used as a substrate for manufacturing the polarization separation element. .

The polarization beam splitting element manufactured by such a method can be manufactured with good tact as compared with the conventional example.
In addition, since the manufactured polarization separation element has a substantially constant film thickness of the adhesive layer (A) 4, it has high reliability as an element,
Variations in quality between elements are also small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent substrate, the P polarized light transmittance is about 98%. The refractive index in the extraordinary ray direction of the organic birefringent film 5 and the refractive index of the adhesive layer (B) 6 are 1.58, which are almost the same value, and the diffraction efficiency is also high. Furthermore, since the refractive index of the adhesive layer (A) 4 is the same 1.58,
The adhesive layer (A) 4 and the adhesive layer (B) 6 can use the same type of adhesive agent, and the cost can be reduced. Further, as the adhesive layer (A) 4 and the adhesive layer (B) 6,
Since the epoxy-based ultraviolet curable resin having a large elastic force is used, the problem that the organic birefringent film 5 is peeled off hardly occurs, and it becomes a highly reliable element as a polarization separation element. Further, the hologram laser unit having the structure as shown in FIG. 18 and the optical pickup using the hologram laser unit use the polarization separation element according to the present invention. It becomes a laser unit and an optical pickup.

[Embodiment 6] A sectional view of a polarization beam splitting element manufactured by carrying out the invention according to claims 1 to 4 and 12 to 22 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). The configuration of FIG. 1 has an optically transparent lower substrate 3 (BK7, thickness:
1.0 mm), adhesive layer (A) 4 (epoxy UV curable resin, refractive index 1.58, thickness: 0.02 mm), organic birefringent film 5 (extraordinary ray direction refractive index 1.58, ordinary ray) Directional refractive index 1.67, thickness: 0.1 mm), adhesive layer (B) 6
(Epoxy UV curable resin, refractive index 1.58, thickness: 0.04 mm), optically transparent upper substrate 7 (BK7,
Thickness: 1.0 mm). On the organic birefringent film 5, a concave-convex diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%, first-order diffracted light diffraction efficiency of about 40%) is formed. The adhesive layer (B) 6 fills the groove. The polarization separation element having the configuration shown in FIG. 1 operates as described in the prior art.
The procedure for producing the polarization beam splitting element having the structure shown in FIG. 1 will be described below with reference to FIGS.

(1). Diameter 100 mm, thickness 1.0 m
m, an optically transparent lower substrate wafer (BK) having an orientation flat with a length of 30 mm at the end.
7 glass substrate) 22 to spin table 21 of spinner
The optically transparent lower substrate wafer 22 and the spin table 21 were placed so that their centers coincided with each other, and vacuum adsorption was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 19
FIG. 7A is a diagram showing a state in which an optically transparent lower substrate wafer 22 is placed on a spin table 21 and vacuum suction is performed. (2). Epoxy UV curable resin was dropped as an adhesive on the optically transparent lower substrate wafer 22, and the spin table 21 was rotated together with the substrate at 700 rpm to adjust the epoxy UV curable resin 20 to a constant thickness.

(3). Diameter 80 mm, maximum length 87.2 m
An organic birefringent film 33 shown in FIG. 19B having a thickness of m and a thickness of 100 μm was prepared. FIG. 19B is a view of the optically transparent lower substrate wafer 22 and the organic birefringent film 33 as viewed from directly above. Protective films are attached to both surfaces of the organic birefringent film 33. The shape is the same as that of the organic birefringent film 23 used in Example 4, with a square portion having a side of 8.9 mm added to the center of the line segment indicating the orientation flat. Therefore, the extraordinary ray direction of the organic birefringent film 33 is indicated by the orientation flats of the three sides parallel to each other. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. FIG. 19
FIG. 6C is a diagram in which the epoxy-based ultraviolet curable resin 20 is applied to the optically transparent lower substrate wafer 22 to have a constant film thickness, and the organic birefringent film 33 is to be disposed thereon.

(4). The organic birefringent film 33 is arranged with the surface from which the protective film is peeled downward, so that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 33 coincide with each other.
After sticking, the spin table 21 was rotated again. When the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 33 are deviated from each other, these directions are aligned with each other.
The organic birefringent film 33 was rotated using a fine needle. Finally, as shown in FIG. 20A, the position was adjusted so that the orientation flat portion of the square portion of the organic birefringent film 33 coincided with the center portion of the orientation flat portion of the optically transparent lower substrate wafer 22.

(5) The epoxy UV curable resin 20 was cured by irradiating it with UV light for several minutes with a high pressure mercury lamp. The epoxy-based UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using acetone. FIG. 20B is a perspective view showing a state in which the organic birefringent film 33 is placed on the optically transparent lower substrate wafer 22 and the epoxy ultraviolet curable resin 20 is cured by being irradiated with UV light. Is.

(6). A metallographic microscope equipped with a CCD camera confirmed that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 33 were parallel to each other with an accuracy of 1 °. Further, the thickness of the produced substrate was measured, and the thickness of the optically transparent lower substrate wafer 22 and the thickness of the organic birefringent film 33 were subtracted from the measured values to obtain the adhesive layer thickness, which was 20 to 22 μm. (7). The protective film on the surface of the organic birefringent film 33 which was not peeled off was peeled off, and the surface was washed. (8). Organic birefringent film 33 attached to an optically transparent substrate
A diffraction grating was formed on the surface by photolithography and dry etching.

(9) Spacers (metal pieces having a side length of 5 mm and a thickness of 40 μm) 26 are installed at four positions at the ends of the organic birefringent film 33, and the epoxy ultraviolet curing resin 24 is dropped from the vicinity of the center to perform The transparent upper substrate wafer 25 was placed with the surface having the antireflection film facing upward. Figure 21
(A) shows an organic birefringent film 33 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21 with an epoxy ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged. (10). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When it was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24.
FIG. 21B is a perspective view showing how UV light is emitted.

(11). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (12). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

In this way, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 33 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

In the method of manufacturing the polarization beam splitting element of Example 6,
The direction of the orientation flat of the optically transparent lower substrate wafer 22 and the direction of the orientation flat of the organic birefringent film 33 are accurate to 1 °.
An optically transparent lower substrate wafer 22 to which was adhered was prepared. The accuracy of measuring the refractive index of the organic birefringent film 33 used is about 1 °, and the orientation flat direction of the optically transparent lower substrate wafer 22 and the organic birefringent film 33 are used.
It has been found that the yield exceeds about 90% when the optically transparent lower substrate wafer 22 to which the organic birefringent film 33 is attached is used with an orientation flat direction of within 2 °. When the angle shift of 2 ° or more occurs, the yield decreases due to the decrease of the diffraction efficiency of the polarization separation element.

Since this substrate was manufactured by using the method of rotating the spin table to adjust the thickness of the adhesive layer, the error in the thickness of the adhesive layer is about 10% in the whole wafer. Also,
By using the organic birefringent film to which the protective film is attached, scratches and foreign substances are not easily attached to the organic birefringent film in each process, and a substrate with improved quality can be used as a substrate for manufacturing the polarization separation element. . The shape of the organic birefringent film 33 used is the same as that of the organic birefringent film 23 used in Example 4, with a square portion added to the center of the line segment indicating the orientation. for that reason,
By adjusting the position of the orientation flat portion of the square-shaped portion of the organic birefringent film 33 so as to coincide with the center portion of the orientation flat portion of the optically transparent lower substrate wafer 22, the direction of the extraordinary ray of the organic birefringent film 33 and the optical direction of the optical axis can be adjusted. The orientation of the orientation flat of the optically transparent lower substrate wafer 22 can be aligned. Further, the center of the optically transparent lower substrate wafer 22 and the center of the circle of the organic birefringent film 33 coincide with each other.

The polarization separation element manufactured by such a method mainly utilizes the coincidence of the orientation flats of the optically transparent lower substrate wafer 22 and the organic birefringent film 33, so that it is more tacit than the conventional example. It is possible to manufacture, and the manufactured polarization separation element has an adhesive layer (A) 4
Since the film thickness of is almost constant, the reliability as an element is high, and the variation in quality between elements is small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%.
The extraordinary ray direction refractive index of the organic birefringent film 5 and the adhesive layer (B) 6
Has a refractive index of 1.58, which is almost the same value and a high diffraction efficiency. Further, since the adhesive layers (A) 4 also have the same refractive index of 1.58, the adhesive layers (A) 4 and the adhesive layers (B) 6 can use the same type of adhesive agent, which reduces the cost. It is possible. Also, the adhesive layer (A) 4 and the adhesive layer (B)
As 6, an epoxy-based ultraviolet curable resin having a large elastic force is used, and a defect such as peeling of the organic birefringent film 5 is unlikely to occur, and a highly reliable element as a polarization separation element is obtained.

[Embodiment 7] A sectional view of a polarization beam splitting element manufactured by carrying out the invention according to claims 8 to 24 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers,
They are distinguished by the symbols (A) and (B). In the configuration of FIG. 1, the lower transparent substrate 3 (BK7, thickness: 1.0 mm), the adhesive layer (A) 4 (acrylic ultraviolet curable resin, refractive index 1.58, thickness: 0.02 mm) are arranged from the bottom. , Organic birefringent film 5 (refractive index 1.58 for extraordinary ray, 1.6 for ordinary ray)
7, thickness: 0.1 mm), adhesive layer (B) 6 (acrylic UV curable resin, refractive index 1.58, thickness: 0.04 m
m) and the upper transparent substrate 7 (BK7, thickness: 1.0 mm). The organic birefringent film 5 has an uneven diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S
A polarized light transmittance of about 1% and a first-order diffracted light diffraction efficiency of about 40%) are formed, and the groove is filled with the adhesive layer (B) 6. The polarization splitting element of FIG. 1 operates as described in the prior art. The procedure for manufacturing the polarization beam splitting element having the structure of FIG. 1 will be described below with reference to FIGS. Also,
FIG. 25 shows the configuration of the hologram laser unit and the optical pickup using the manufactured polarization separation element.

(1). Diameter 100 mm, thickness 1.0 m
m, optically transparent lower substrate wafer (BK7 glass substrate) with orientation flats formed at the edges
22 was placed on the spin table 21 of the spinner so that the center of the optically transparent lower substrate wafer 22 and the center of the spin table 21 were aligned with each other, and vacuum suction was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 22A is a diagram showing a state in which the optically transparent lower substrate wafer 22 is placed on the spin table 21 and vacuum suction is performed. (2). Acrylic UV curable resin is dropped as an adhesive on the optically transparent lower substrate wafer 22 and the whole substrate 7
It was rotated at 00 rpm to adjust the acrylic ultraviolet curable resin to a constant film thickness.

(3). An organic birefringent film 23 having a diameter of 80 mm and a film thickness of 100 μm was prepared. FIG. 22B is a view of the optically transparent lower substrate wafer 22 and the birefringent film 23 having an orientation flat indicating the extraordinary ray direction, as viewed from directly above. The organic birefringent film 23 has protective films attached to both surfaces thereof, and an orientation flat indicating an extraordinary ray direction is formed at an end thereof. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. FIG. 22C shows an optically transparent lower substrate wafer 22.
FIG. 3 is a diagram in which an acrylic ultraviolet curable resin 20 is applied on a certain thickness and an organic birefringent film 23 is to be disposed thereon.

(4). The organic birefringent film 23 with the surface from which the protective film is peeled downward is observed with a CCD camera so that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the birefringent film 23 are aligned with each other, and the angle is shifted. Was adjusted, placed, and pasted. Then, the spin table 21 was rotated again. When it is determined that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 are deviated by observing with a CCD camera, a fine needle is used so that these directions coincide with each other. Using the organic birefringent film 23, the position was adjusted by rotating it. FIG. 23 (a)
FIG. 4 is a top view showing a state in which the organic birefringent film 23 is installed so that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 are aligned with each other.

(5). The acrylic ultraviolet curing resin 20 was cured by irradiating it with ultraviolet rays for several minutes with a high pressure mercury lamp. The acrylic UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using isopropyl alcohol. FIG. 23B shows the organic birefringent film 2
3 is placed on the optically transparent lower substrate wafer 22 and U
FIG. 6 is a perspective view showing a state where the acrylic ultraviolet curable resin 20 is cured by being irradiated with V light. CC
Observing the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 using a D camera, it was found to be almost 1
It was confirmed that they were in the same direction with an accuracy of °.

(6). The protective film on the surface of the organic birefringent film 23 which was not peeled off was peeled off, and the surface was washed. (7). A diffraction grating was formed on the surface of the organic birefringent film 25 attached to the optically transparent lower substrate wafer 22 by photolithography and dry etching. FIG. 23
FIG. 3C is a top view schematically showing the organic birefringent film 23 having the diffraction grating formed on the optically transparent lower substrate wafer 22.

(8). Spacers (5 mm on each side, a metal piece having a thickness of 40 μm) 26 are attached to the end portions on the organic birefringent film 23.
It is installed in a place, and the acrylic UV curable resin 24 is dripped from the vicinity of the center, and the optically transparent upper substrate wafer 25 is
The surface provided with the antireflection film was placed on the upper side. Figure 24
(A) is an organic transparent birefringent film 23 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21, with an acrylic ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged. (9). While maintaining parallel with the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure, and when the optically transparent upper substrate wafer 25 is no longer lowered, UV light is emitted from above. Was irradiated to cure the acrylic ultraviolet curable resin 24. FIG. 24B is a perspective view showing a state where UV light is emitted.

(10). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (11). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

In this way, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 23 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

(12) After that, the semiconductor laser 11 and the light receiving element (photodiode) are manufactured by using the polarization separating element 1 having the structure shown in FIG. ) 12 is mounted on the mounting position of the cap 9 of the laser unit in which 12 is mounted on a common stem, and the polarization separation element 1 is horizontally adjusted. (13). As shown in FIGS. 2 (a) and 2 (b), acrylic UV curable resin 8 is applied to the lower four corners of the side surface of the polarization separation element 1 by using a dispenser, and is irradiated with ultraviolet rays to be fixed to fix the hologram. A laser unit was produced. (14). Next, as shown in FIG. 25, the hologram laser unit, the λ / 4 plate 10, the optically adjusted collimating lens 30, and the objective lens 31 are used to record, reproduce, or erase information on the optical disc 32. An optical pickup optical system is formed.

In the method of manufacturing the polarization beam splitting element of Example 7,
The direction of the orientation flat of the organic birefringent film 23 with respect to the direction of the orientation flat of the optically transparent lower substrate wafer 22 is detected and made substantially parallel, and then the organic birefringent film 23 is placed on the optically transparent lower substrate wafer 22.
Pasted on. Therefore, it was possible to manufacture an optically transparent lower substrate wafer to which the organic birefringent film 23 in which these angles were parallel to each other with an accuracy of 1 ° was attached. This is characterized in that before the organic birefringent film 23 is attached to the optically transparent lower substrate wafer 22, it is detected how much the orientation flats of them are deviated from each other. Detecting the angular deviation before sticking means that when an optically transparent lower substrate wafer having the organic birefringent film 23 stuck thereto is produced, the quality variation as a wafer is reduced and the diffraction grating in the lithography process is reduced. Improve the formation yield. Further, since this substrate was manufactured by adjusting the thickness of the adhesive layer using a rotating spin table, the error in the thickness of the adhesive layer is about 10% in the whole wafer. Further, by using the organic birefringent film to which the protective film is attached, scratches and foreign substances are hard to be attached to the organic birefringent film in each step, and a substrate with improved quality as a substrate for manufacturing a polarization separation element can be obtained. Can be used.

The polarization separation element manufactured by such a method can be manufactured with good tact compared to the conventional example by reducing the dispersion between the diffraction grating elements, and the manufactured polarization separation element is bonded. Since the layer (A) 4 has a substantially constant film thickness, it is highly reliable as an element. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%.
The extraordinary ray direction refractive index of the organic birefringent film 5 and the adhesive layer (B) 6
Has a refractive index of 1.58, which is almost the same value and a high diffraction efficiency. Further, since the adhesive layers (A) 4 also have the same refractive index of 1.58, the adhesive layers (A) 4 and the adhesive layers (B) 6 can use the same type of adhesive agent, which reduces the cost. It is possible. Also, the adhesive layer (A) 4 and the adhesive layer (B)
As 6, an acrylic ultraviolet-curable resin having a large elastic force is used, and a defect such as peeling of the organic birefringent film 5 is unlikely to occur, and the device becomes a highly reliable element as a polarization separation element. In addition, in the hologram laser unit having the configuration as shown in FIG. 25 and the optical pickup using the same,
Since the polarization splitting element according to the present invention is used, the hologram laser unit and the optical pickup have better tact and higher reliability than the conventional example.

[Embodiment 8] A sectional view of a polarization beam splitting element manufactured by carrying out the invention according to claims 1 to 4 and 12 to 24 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers, they are distinguished by the symbols (A) and (B). The configuration of FIG. 1 is from the bottom to the bottom transparent substrate 3 (BK7, thickness: 1.0).
mm), adhesive layer (A) 4 (acrylic ultraviolet curable resin, refractive index 1.58, thickness: 0.02 mm), organic birefringent film 5 (extraordinary ray direction refractive index 1.58, ordinary ray direction refraction) Ratio 1.67, thickness: 0.1 mm), adhesive layer (B) 6 (acrylic UV curable resin, refractive index 1.58, thickness:
0.04 mm), upper transparent substrate 7 (BK7, thickness: 1.
0 mm). The organic birefringent film 5 has an uneven diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%, first-order diffracted light diffraction efficiency of about 4%).
0%) is formed and the groove is filled with the adhesive layer (B) 6. The polarization splitting element of FIG. 1 operates as described in the prior art. The procedure for producing the polarization beam splitting element having the structure of FIG. 1 will be described below with reference to FIGS. In addition, the configuration of a hologram laser unit and an optical pickup using the manufactured polarization separation element is shown in FIG.
8 shows.

(1). Diameter 100 mm, thickness 1.0 m
m, optically transparent lower substrate wafer (BK7 glass substrate) with orientation flats formed at the edges
22 was placed on the spin table 21 of the spinner so that the center of the optically transparent lower substrate wafer 22 and the center of the spin table 21 were aligned with each other, and vacuum suction was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 26A is a diagram showing a state in which the optically transparent lower substrate wafer 22 is placed on the spin table 21 and vacuum suction is performed. (2). Acrylic UV curable resin is dropped as an adhesive on the optically transparent lower substrate wafer 22 and the whole substrate 7
It was rotated at 00 rpm to adjust the acrylic ultraviolet curable resin to a constant film thickness.

(3). An organic birefringent film 23 having a diameter of 80 mm and a film thickness of 100 μm was prepared. FIG. 26B is a view of the optically transparent lower substrate wafer 22 and the birefringent film 23 having an orientation flat indicating the extraordinary ray direction, as viewed from directly above. The organic birefringent film 23 has protective films attached to both surfaces thereof, and an orientation flat indicating an extraordinary ray direction is formed at an end thereof. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. FIG. 26C shows an optically transparent lower substrate wafer 22.
FIG. 3 is a diagram in which an acrylic ultraviolet curable resin 20 is applied on a certain thickness and an organic birefringent film 23 is to be disposed thereon.

(4). The organic birefringent film 23 is arranged with the surface from which the protective film is peeled downward, so that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 23 are aligned.
After sticking, the spin table 21 was rotated again. When the directions of the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 are deviated, the organic birefringent film 25 is rotated by using a fine needle so that these directions coincide with each other. It was

(5). The acrylic ultraviolet curing resin 20 was cured by irradiating it with ultraviolet rays for several minutes with a high pressure mercury lamp. The acrylic UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using isopropyl alcohol. FIG. 26D shows the organic birefringent film 2
3 is placed on the optically transparent lower substrate wafer 22 and U
FIG. 6 is a perspective view showing a state where the acrylic ultraviolet curable resin 20 is cured by being irradiated with V light.

(6). It was confirmed by a metallographic microscope equipped with a CCD camera that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 23 were parallel to each other with an accuracy of 1 °. Further, the thickness of the produced substrate was measured, and the thickness of the optically transparent lower substrate wafer 22 and the thickness of the organic birefringent film 25 were subtracted from the measured values to obtain the adhesive layer thickness, which was 20 to 22 μm. (7). The protective film on the surface of the organic birefringent film 23 which was not peeled off was peeled off, and the surface was washed. (8). A diffraction grating was formed on the surface of the organic birefringent film 25 attached to the optically transparent lower substrate wafer 22 by photolithography and dry etching.

(9). Spacers (5 mm on each side, a metal piece having a thickness of 40 μm) 26 are attached to the end portions on the organic birefringent film 23.
It is installed in a place, and the acrylic UV curable resin 24 is dripped from the vicinity of the center, and the optically transparent upper substrate wafer 25 is
The surface provided with the antireflection film was placed on the upper side. FIG. 27
(A) is an organic transparent birefringent film 23 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21, with an acrylic ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged. (10). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When no more dropped, UV light was irradiated from above to cure the acrylic ultraviolet curable resin 24.
FIG. 27B is a perspective view showing a state in which UV light is radiated.

(11). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (12). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

In this way, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 23 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

(13) After that, the semiconductor laser 11 and the light receiving element (photodiode) are manufactured by using the polarization separating element 1 having the structure shown in FIG. ) 12 is mounted on the mounting position of the cap 9 of the laser unit in which 12 is mounted on a common stem, and the polarization separation element 1 is horizontally adjusted. (14). As shown in FIGS. 2 (a) and 2 (b), acrylic UV curable resin 8 is applied to the lower four corners of the side surface of the polarization separation element 1 by using a dispenser, and is irradiated with ultraviolet rays to be fixed to fix the hologram. A laser unit was produced. (15). Next, as shown in FIG. 28, by using the hologram laser unit, the λ / 4 plate 10, the optically adjusted collimator lens 30, and the objective lens 31, recording, reproducing, or erasing of information on the optical disc 32 is performed. An optical pickup optical system is formed.

In the method of manufacturing the polarization beam splitting element of Example 8,
The direction of the orientation flat of the optically transparent lower substrate wafer 22 and the direction of the orientation flat of the organic birefringent film 23 are accurate to 1 °.
An optically transparent lower substrate wafer was prepared with the above attached. The accuracy of measuring the refractive index of the organic birefringent film used is about 1 °, and the orientation flat direction of the optically transparent lower substrate wafer 22 and the orientation flat direction of the organic birefringent film 23 are accurate within 2 °. It has been found that the yield exceeds about 90% when the optically transparent lower substrate wafer 22 having the organic birefringent film 23 attached thereto is used. When the angle shift of 2 ° or more occurs, the yield decreases due to the decrease of the diffraction efficiency of the polarization separation element.

Since this substrate was manufactured by using the method of rotating the spin table to adjust the thickness of the adhesive layer, the error of the adhesive layer thickness in the whole wafer is about 10%. Also,
By using the organic birefringent film to which the protective film is attached, scratches and foreign substances are not easily attached to the organic birefringent film in each process, and a substrate with improved quality can be used as a substrate for manufacturing the polarization separation element. .

The polarization splitting element manufactured by such a method mainly utilizes the coincidence of the orientation flats of the optically transparent lower substrate wafer 22 and the organic birefringent film 23. Yield is improved. Further, since the manufactured polarization separation element has a substantially uniform film thickness of the adhesive layer (A) 4, it has high reliability as an element, and variations in quality among the elements are small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. Since the polarization separation element has an antireflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, the P polarized light transmittance is about 98%. The refractive index in the extraordinary ray direction of the organic birefringent film 5 and the refractive index of the adhesive layer (B) 6 are 1.58, which are almost the same value, and the diffraction efficiency is also high. Further, since the adhesive layers (A) 4 also have the same refractive index of 1.58, the adhesive layers (A) 4 and the adhesive layers (B) 6 can use the same type of adhesive agent, which reduces the cost. It is possible. Further, the adhesive layer (A) 4 and the adhesive layer (B) 6
As such, since an acrylic ultraviolet curable resin having a large elastic force is used, a problem such as peeling of the organic birefringent film 5 is unlikely to occur, and the element becomes a highly reliable element as a polarization separation element. Further, the hologram laser unit having the structure as shown in FIG. 28 and the optical pickup using the hologram laser unit use the polarization separation element according to the present invention, and thus the tact is good and the hologram is highly reliable as compared with the conventional example. It becomes a laser unit and an optical pickup.

[Embodiment 9] A sectional view of a polarization beam splitting element manufactured by carrying out claims 1 to 4 and 12 to 22 is as shown in FIG. In the configuration of FIG. 1, since there are two adhesive layers,
They are distinguished by the symbols (A) and (B). The configuration of FIG. 1 has an optically transparent lower substrate 3 (BK7, thickness: 1.0 m from the bottom).
m), the adhesive layer (A) 4 (epoxy type ultraviolet curable resin,
Refractive index 1.58, thickness: 0.02 mm, organic birefringent film 5 (refractive index in extraordinary ray direction 1.58, refractive index in ordinary ray direction 1.67, thickness: 0.1 mm), adhesive layer (B ) 6 (epoxy UV curable resin, refractive index 1.58, thickness: 0.
04 mm), optically transparent upper substrate 7 (BK7, thickness:
1.0 mm). On the organic birefringent film 5, a concave-convex diffraction grating 2 (grating depth 4 μm, pitch 2 μm, P-polarized light transmittance of about 98%, S-polarized light transmittance of about 1%, first-order diffracted light diffraction efficiency of about 40%) is formed. And the groove is bonded to the adhesive layer (B) 6
Has a structure to be filled. The polarization splitting element of FIG. 1 operates as described in the prior art. The procedure for manufacturing the polarization beam splitting element having the structure of FIG. 1 will be described below with reference to FIGS.

(1). Diameter 100 mm, thickness 1.0 m
m, an optically transparent lower substrate wafer (BK) having an orientation flat with a length of 30 mm at the end.
7 glass substrate) 22 to spin table 21 of spinner
The optically transparent lower substrate wafer 22 and the spin table 21 were placed so that their centers coincided with each other, and vacuum adsorption was performed. At the time of installation, the surface of the optically transparent lower substrate wafer 22 provided with the antireflection film was faced down. FIG. 29
(A) is a diagram showing a state in which an optically transparent lower substrate wafer 24 is placed on a spin table 21 and vacuum suction is performed. (2). Epoxy UV curable resin is dropped as an adhesive on the optically transparent substrate, and the spin table 21 is attached together with the substrate.
Was rotated at 700 rpm to adjust the epoxy ultraviolet curable resin 20 to a constant film thickness.

(3). An organic birefringent film 34 shown in FIG. 29B having a diameter of 96 mm and a film thickness of 100 μm was prepared.
FIG. 29B is a view of the optically transparent lower substrate wafer 22 and the organic birefringent film 34 as viewed from directly above. Protective films are attached to both surfaces of the organic birefringent film 34. The organic birefringent film 34 is formed with an orientation flat showing the extraordinary ray direction with a length of 17.4 mm. The shape is almost the same as that of the organic birefringent film 23 used in Example 4, but the diameter and the length of the orientation flat are different. First, the protective film on one surface was peeled off, and the surface of the organic birefringent film was washed. In FIG. 29C, the epoxy-based UV curable resin 20 is applied to the optically transparent lower substrate wafer 22 to a constant thickness, and the organic birefringent film 3 is applied thereon.
4 is a diagram in which 4 is being arranged. FIG.

(4). The organic birefringent film 34 is arranged with the surface from which the protective film is peeled downward, so that the orientation flats of the optically transparent lower substrate wafer 22 and the orientation flats of the organic birefringent film 34 coincide with each other.
After sticking, the spin table 21 was rotated again. When the directions of the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 34 are deviated, the organic birefringent film 34 is rotated by using a fine needle so that these directions coincide with each other. It was Finally, as shown in FIG. 30A, the position was adjusted so that the center of the orientation flat portion of the organic birefringent film 34 and the center of the orientation flat portion of the optically transparent lower substrate wafer 22 coincided with each other.

(5). The epoxy-based UV curable resin 20 was cured by irradiating it with UV light for several minutes with a high pressure mercury lamp. The epoxy-based UV curable resin 20 attached to the edge of the optically transparent lower substrate wafer 22 was removed using acetone. FIG. 30B is a perspective view showing a state in which the organic birefringent film 34 is placed on the optically transparent lower substrate wafer 22 and UV light is irradiated to cure the epoxy ultraviolet curable resin 20. Is.

(6). It was confirmed by a metallographic microscope equipped with a CCD camera that the orientation flat of the optically transparent lower substrate wafer 22 and the orientation flat of the organic birefringent film 34 were parallel to each other with an accuracy of 1 °. The thickness of the produced substrate was measured, and the thickness of the optically transparent lower substrate wafer 22 and the thickness of the organic birefringent film 34 were subtracted from the measured values to obtain the adhesive layer thickness, which was 20 to 22 μm. (7). The protective film on the surface of the organic birefringent film 34 which was not peeled off was peeled off, and the surface was washed. (8) A diffraction grating was formed on the surface of the organic birefringent film 34 attached to the optically transparent substrate by photolithography and dry etching.

(9). A spacer (5 mm on each side, a metal piece having a thickness of 40 μm) 26 is attached to the end of the organic birefringent film 34.
It is installed in a place, and an epoxy-based ultraviolet curable resin 24 is dropped from the vicinity of the center, and an optically transparent upper substrate wafer 25 is
The surface provided with the antireflection film was placed on the upper side. Figure 31
(A) shows an organic birefringent film 34 adhered with an adhesive 20 on an optically transparent lower substrate wafer 22 placed on a spin table 21 with an epoxy ultraviolet curable resin 24 interposed therebetween. FIG. 7 is a front sectional view showing an example in which an optically transparent upper substrate wafer 25 is arranged. (10). While keeping parallel to the optically transparent lower substrate wafer 22, the optically transparent upper substrate wafer 25 is continuously pressed from above with a constant pressure to obtain an optically transparent upper substrate wafer 25.
When it was no longer lowered, UV light was irradiated from above to cure the epoxy ultraviolet curing resin 24.
FIG. 31B is a perspective view showing a state in which UV light is emitted.

(11). The substrate manufactured in the previous step was fixed to a dicing tape, and a line interval was 4.7 mm using a dicing blade having a thickness of 0.5 mm, and the vertical and horizontal directions were 12 as shown in FIG. The line was cut. (12). After that, the entire dicing tape was irradiated with ultraviolet rays to peel off each element from the tape, and 144 polarization separation elements were obtained.

In this way, the polarization beam splitting element 1 having the structure shown in the sectional view of FIG. 1 was obtained. When the diffraction efficiency and the wavefront aberration of the produced 144 polarization separation elements were measured, the allowable value of the diffraction efficiency of the first-order diffracted light was 40%, and the allowable value of the wavefront aberration was 0.
At 02 rms (λ), the yield exceeded 90%.
When the thickness of the adhesive layer (A) 4 between the optically transparent lower substrate wafer 22 and the organic birefringent film 34 was measured by observation with a metallographic microscope, it was 20 to 22 μm for each element.

In the method of manufacturing the polarization separation element of Example 9,
The direction of the orientation flat of the optically transparent lower substrate wafer 22 and the direction of the orientation flat of the organic birefringent film 34 are accurate to 1 °.
An optically transparent lower substrate wafer 22 to which was adhered was prepared. The accuracy of measuring the refractive index of the organic birefringent film 34 used is about 1 °, and the direction of the orientation flat of the optically transparent lower substrate wafer 22 and the organic birefringent film 34.
It has been found that the yield exceeds about 90% when the optically transparent lower substrate wafer 22 to which the organic birefringent film 28 is attached with the orientation flat direction of 2 is accurate within 2 °. When the angle shift of 2 ° or more occurs, the yield decreases due to the decrease of the diffraction efficiency of the polarization separation element.

Since this substrate was manufactured by using the method of rotating the spin table to adjust the thickness of the adhesive layer, the error in the thickness of the adhesive layer is about 10% in the whole wafer. Also,
By using the organic birefringent film to which the protective film is attached, scratches and foreign substances are not easily attached to the organic birefringent film in each process, and a substrate with improved quality can be used as a substrate for manufacturing the polarization separation element. . The shape of the organic birefringent film 34 used is the same as the shape of the organic birefringent film 23 used in Example 4, but the diameter and the length of the line segment indicating the orientation are different. By adjusting the position of the center of the orientation flat portion of the birefringent film 28 and the center of the orientation flat portion of the optically transparent lower substrate wafer 22, the extraordinary ray direction of the organic birefringent film 34 and the optically transparent lower portion are adjusted. Substrate wafer 22
In addition to being able to match the orientation flat directions, the center of the optically transparent lower substrate wafer 22 and the center of the circle of the organic birefringent film 34 are designed to coincide with each other.

The polarization separation element manufactured by such a method mainly utilizes the coincidence of the orientation flats of the optically transparent lower substrate wafer 22 and the organic birefringent film 34, so that it is manufactured with a better cycle than the conventional example. In addition, the manufactured polarization separation element has high reliability as an element because the film thickness of the adhesive layer (A) 4 is substantially constant, and variation in quality between elements is small. Since the organic birefringent film is used as the optically anisotropic film, the cost of the polarization separation element is low. The polarization separation element has an anti-reflection film on the lower side of the optically transparent lower substrate and the upper side of the optically transparent upper substrate, so that the P polarized light transmittance is about 98%. The refractive index in the extraordinary ray direction of the organic birefringent film 5 and the refractive index of the adhesive layer (B) 6 are 1.58, which are almost the same value, and the diffraction efficiency is also high. Furthermore, since the adhesive layers (A) 4 have the same refractive index of 1.58, it is possible to use adhesives of the same quality for the adhesive layers (A) 4 and (B) 6.
It is possible to reduce the cost. Further, as the adhesive layer (A) 4 and the adhesive layer (B) 6, an epoxy-based ultraviolet curable resin having a large elastic force is used, and a defect such as peeling of the organic birefringent film 5 is unlikely to occur, and polarization separation is performed. The element becomes a highly reliable element.

The specific embodiments of the present invention have been described above, but it goes without saying that the present invention can be applied without being limited to these embodiments. In the examples, the angle deviation between the optically transparent lower substrate wafer and the orientation flat of the birefringent film was visually detected with a CCD camera, but the refractive index of the birefringent film was measured using laser light, or Alternatively, the angle deviation may be optically detected by using an optical element. When manufacturing a birefringent film having a shape as shown in the example from a large area birefringent film sheet, an error occurs when forming an orientation flat so as to be parallel to the direction of the extraordinary ray direction or the ordinary ray direction. May occur. In such a case, the method of optically detecting the extraordinary ray or ordinary ray direction is effective. For example, although the structure as shown in FIG. 1 is given as an example of the polarization separation element, a λ / 4 plate is used as the adhesive layer (A) 4,
An element having a structure including it between the birefringent film 5 may be used. Further, although the extraordinary ray direction of the birefringent film is the orientation flat direction, the ordinary ray direction may be the orientation flat direction. Further, the adhesive adhered to the edge of the optically transparent lower substrate wafer at the time of attaching the birefringent film was removed by using acetone and isopropyl alcohol in this example, but an organic solvent capable of dissolving the adhesive was used. It may be removed, and the process may be performed before or after the adhesive is cured, and there are various removal methods.

Furthermore, in Example 6, an organic birefringent film 23 having the same shape as the organic birefringent film 23 used in Example 4 was added with a square portion with a side of 8.9 mm at the center of the line segment indicating the orientation. Although the refraction film 33 is used, a square portion having a side length of 8.9 mm plays a similar role in other shapes and sizes having an orientation flat. Alternatively, only this portion may be formed and added to the same shape as the organic birefringent film 23 used in Example 4 with an adhesive or the like.

It is also possible to develop a device using the present invention. Thus, the application range of using the present invention is wide, by using, it is possible to produce better tact than the conventional example, and mainly due to the orientation flat match, the adhesive layer film thickness constant, The polarized light separating element has improved reliability.

[0129]

As described above, in the method of manufacturing a polarization separation element according to the first aspect, in the step of forming a diffraction grating after attaching an optically anisotropic film to an optically transparent substrate wafer, Since the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected, the yield of forming the diffraction grating is improved, the yield of the polarization beam splitting element is improved, and the cost can be reduced. In the method for producing a polarization beam splitting element according to claim 2, the optically transparent substrate wafer to which the optically anisotropic film is attached has either one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film. It has an orientation flat that indicates the direction of. Therefore, it is possible to achieve the effect of simplifying the process and increasing the effect of the invention according to claim 1.

In the method for manufacturing a polarization separation element according to claim 3, one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film and the orientation flat direction of the optically transparent substrate wafer are substantially the same. An optically transparent substrate wafer having an optically anisotropic film attached thereto is used. Therefore, it is easy to manufacture the polarization separation element,
It is possible to produce the effect that the polarization separation element can be manufactured with good tact. Further, the reliability as an element is high and the variation in quality is small. In the method for manufacturing a polarization separation element according to claim 4, the optically transparent substrate wafer on which the optically anisotropic film is adhered has one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film. The orientation flats of the optically transparent substrate wafer are parallel to each other with an accuracy within 2 °. Therefore, the effect of increasing the effect of the invention according to claims 1 to 3 can be obtained.

In the method of manufacturing a polarization beam splitting element according to the fifth aspect, the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected with reference to the orientation flat of the optically transparent substrate wafer. Therefore, it is possible to achieve the effect of simplifying the process and increasing the effect of the invention according to claim 1. In the method for manufacturing a polarization separation element according to claim 6, the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film on the optically transparent substrate wafer is one of the steps of forming a diffraction grating. During the process, before the process, or during transportation to the process. Therefore, the yield of forming the diffraction grating can be improved, and the yield and quality of the polarization separation element can be improved. In the method of manufacturing a polarization beam splitting element according to a seventh aspect, the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected by using an exposure device or a reduction projection exposure device. Therefore, the process can be simplified, and the yield and reliability of the polarization separation element can be improved.

In the method for manufacturing a polarization separation element according to the eighth aspect, the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is detected before the optically anisotropic film is attached to the optically transparent substrate wafer. To do. Therefore, it is possible to obtain an effect that the direction of either the extraordinary ray direction or the ordinary ray direction of the optically anisotropic film and the orientation flat direction of the optically transparent substrate wafer can be accurately aligned. In the method for manufacturing a polarization beam splitting element according to claim 9, the optically anisotropic film on the optically transparent substrate wafer is such that the optically anisotropic film is oriented in either the ordinary ray direction or the extraordinary ray direction. It has the orientation flat shown.
Therefore, it is possible to achieve the effect of simplifying the process and increasing the effect of the invention according to claim 8.

In the method for manufacturing a polarization separation element according to claim 10, the optical anisotropic film is rotated after detecting one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film,
After that, the optically anisotropic film is attached to the optically transparent substrate wafer. Therefore, it is possible to achieve the effect of simplifying the process and increasing the effect of the invention according to claims 8 and 9. In the method of manufacturing a polarization beam splitting element according to the eleventh aspect, the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed from the angle deviation from the orientation flat direction of the optically transparent substrate wafer. Therefore, it is possible to achieve the effect of simplifying the process and increasing the effect of the invention according to claims 8 and 9.

In the method of manufacturing a polarization beam splitting element according to the twelfth aspect, the optically transparent substrate wafer to which the optically anisotropic film is attached is adhered so as to form an adhesive layer having a substantially constant thickness. Therefore, it is possible to improve the reliability of the polarization separation element and reduce the variation between the elements. In the method of manufacturing a polarization beam splitting element according to claim 13, the optically transparent substrate wafer to which the optically anisotropic film is attached is manufactured by adjusting the film thickness of the adhesive using the rotation of the spin table. . Therefore, it is possible to improve the reliability of the polarization separation element and reduce the variation between the elements.

In the method for manufacturing a polarization beam splitting element according to the fourteenth aspect, the optically transparent substrate wafer having the optically anisotropic film adhered thereto has a uniform film thickness of the adhesive applied on the optically transparent substrate wafer. After the optically anisotropic film is placed on it, the spin table is rotated again so that the adhesive has a constant film thickness. Therefore, it is possible to improve the reliability of the polarization separation element and reduce the variation between the elements. In the method for manufacturing a polarization beam splitting element according to claim 15, a part of a line segment showing an orientation flat of the optically transparent substrate wafer is used as a step of manufacturing the optically transparent substrate wafer to which an optically anisotropic film is attached. Alternatively, it is manufactured by providing a step of aligning the positions of all the line segments with the optically anisotropic film. Therefore, it is possible to facilitate the production of the optically transparent substrate wafer to which the optically anisotropic film is attached, produce the polarization separation element with high yield, and improve the reliability of the element.

In the method for manufacturing a polarization beam splitting element according to the sixteenth aspect, since the optically anisotropic film provided with the separable protective film is used, the generation of scratches on the optically anisotropic film and the contamination of foreign matter are prevented. Adhesion can be reduced and the effect of the invention according to claim 1 can be increased. In the method for producing a polarization separation element according to claim 17, when an organic birefringent film made of a polymer is used as the optically anisotropic film forming the polarization separation element, the polarization separation element can be easily produced. Therefore, the effect that the cost of the material can be reduced can be achieved.

In the method for manufacturing a polarization beam splitting element according to claim 18, the polarization beam splitting element includes an optically transparent lower substrate, a lower adhesive layer (adhesive layer (A)), an optically anisotropic film, and an upper adhesive layer (adhesive). Layer (B)), which is an optically transparent upper substrate, and one of the optically transparent lower substrate and the optically transparent upper substrate is the optically transparent substrate wafer. Therefore, the optically transparent upper substrate can protect the optically anisotropic film and improve the reliability of the device. Claim 19
In the method for manufacturing a polarization separation element according to the above, one of the refractive index in the ordinary ray direction and the refractive index in the extraordinary ray direction of the optically anisotropic film and the adhesive for filling the diffraction grating formed in the optically anisotropic film. Since the layers (B) have almost the same refractive index, it is possible to improve the degree of polarization separation of the polarization separation element. Furthermore, since the refractive index of the adhesive layer (A) on the side where the diffraction grating of the optically anisotropic film is not formed is the same, the same adhesive layer is used as the two adhesive layers sandwiching the optically anisotropic film. Therefore, it is possible to achieve the effects of reducing the cost and simplifying the management.

In the method for manufacturing a polarization separation element according to claim 20, the transmittance of the element is improved by using a transparent substrate having an antireflection film on at least one of the light incident surface or the light emission surface of the polarization separation element. It is possible to produce the effect that the polarized light separating element described above can be manufactured. In the method for producing a polarization beam splitting element according to claim 21, a photosensitive resin is used as an example of an ultraviolet curable resin as an adhesive layer forming the polarization beam splitting element, and the stress of the optically anisotropic film is relaxed as the resin. In addition to the effect of increasing the tact even when using an effective epoxy adhesive or rubber-based adhesive,
The effect of improving the reliability of the element can also be achieved.

Since the polarization separation element described in claim 22 is manufactured by using the method for manufacturing the polarization separation element according to any one of claims 1 to 21, the polarization separation element is low in cost and highly reliable. Separation elements can be realized. Claim 2
The hologram laser unit according to claim 3,
Since the polarization separation element described in 2 is used, it is possible to improve reliability as a hologram laser unit and provide a high-performance hologram laser unit at low cost. Since the optical pickup according to claim 24 is an optical pickup manufactured by using the polarization separation element according to claim 22 or the hologram laser unit according to claim 23, it has improved reliability and high performance. An optical pickup can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a polarization beam splitting element.

FIG. 2 is a structural explanatory view showing an example of a hologram laser unit using a polarization separation element, and FIG. 2 (a) is a perspective view of a main part showing a state where the polarization separation element is mounted on a cap using an adhesive; FIG. 6B is a schematic configuration diagram of a hologram laser unit in which a polarization separation element is arranged on a cap.

FIG. 3 is an explanatory diagram for vertically and horizontally cutting a polarization separation element made of a wafer by dicing.

FIG. 4 is a perspective view of a spin table having alignment pins and two substrates.

FIG. 5 is an explanatory diagram of a bonding method when bonding two plate-shaped substrates.

FIG. 6 is a perspective view of a spin table having no alignment pins, an optically anisotropic film such as a birefringent film, and an optically transparent lower substrate wafer.

FIG. 7 is an explanatory view of a sticking method when sticking an optically anisotropic film such as an organic birefringent film to an optically transparent lower substrate wafer.

FIG. 8 is an explanatory diagram of a method for manufacturing the polarization beam splitting element of Example 1, in which (a) the direction of the extraordinary ray of the organic birefringent film and the direction of the orientation flat of the optically transparent substrate wafer are substantially the same. FIG. 3B is a top view of the optically transparent substrate wafer to which the organic birefringent film is attached, and FIG. 6B is a top view schematically showing a state in which a diffraction grating is formed on the substrate prepared in FIG.

FIG. 9 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 1, wherein (a) is a substrate shown in FIG. 8 (b) coated with an adhesive, and an optically transparent upper substrate wafer is applied thereon. FIG. 3B is a front sectional view showing the installed state, and FIG. 6B is a perspective view showing the installed state up to the optically transparent upper substrate wafer and curing the adhesive by UV light.

FIG. 10 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 2, in which (a) the direction of the extraordinary ray of the organic birefringent film and the direction of the orientation flat of the optically transparent substrate wafer are substantially the same. Top view of the optically transparent substrate wafer to which the organic birefringent film is attached, as shown in FIG.
A front cross-sectional view showing a state in which an adhesive is applied to the substrate indicated by and an optically transparent upper substrate wafer is placed thereon, (c)
FIG. 3 is a perspective view showing a state in which up to an optically transparent upper substrate wafer is installed and an adhesive is cured by UV light.

FIG. 11 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 3 or Example 4, in which (a) is a perspective view showing a state in which an optically transparent lower substrate wafer is installed on a spin table; ) Is a top view of an optically transparent lower substrate wafer with an orientation flat and an organic birefringent film, (c)
Is a perspective view showing a state in which an adhesive is applied on the optically transparent lower substrate wafer and is extended to a constant film thickness, (d) is an organic birefringent film placed on the adhesive, and the adhesive is applied by UV light. It is a perspective view which shows a mode that it is hardening.

FIG. 12 (a) is a top view showing a state in which an organic birefringent film is attached on an optically transparent lower substrate so that the orientation flats coincide with each other, and FIG. 12 (b) shows diffraction on the substrate produced in (a). It is a top view which showed typically the mode that the lattice was formed.

FIG. 13 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 3 or Example 4, in which (a) is a substrate shown in FIG. 11 (d) coated with an adhesive and is optically transparent. FIG. 4B is a front sectional view showing a state where the upper substrate wafer is installed, and FIG. 9B is a perspective view showing a state where the optically transparent upper substrate wafer is installed and the adhesive is cured by UV light.

14A and 14B are explanatory views of a method for manufacturing a polarization beam splitting element of Example 5, in which FIG. 14A is a perspective view showing a state in which an optically transparent lower substrate wafer is installed on a spin table, and FIG. 14B is an orientation flat. FIG. 3C is a top view of the optically transparent lower substrate wafer having the above and the organic birefringent film, and FIG. 7C is a perspective view showing a state in which an adhesive is applied on the optically transparent lower substrate wafer and the film is extended to a constant thickness.

FIG. 15 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 5, in which (a) aligns a part of the orientation flat part of the optically transparent lower substrate wafer with the orientation flat part of the organic birefringent film. Then, a top view showing a state in which the organic birefringent film is attached on the optically transparent lower substrate wafer, (b) shows that the organic birefringent film is placed on the adhesive and the adhesive is cured by UV light. It is a perspective view showing a situation.

FIG. 16 is an explanatory diagram of a method of manufacturing the polarization beam splitting element of Example 5, and is a schematic diagram showing a substrate transport path with a CCD camera and a reduction projection exposure apparatus.

FIG. 17 is an explanatory diagram of a method for manufacturing the polarization beam splitting element of Example 5, in which (a) schematically shows a state in which a diffraction grating is formed on a birefringent film attached on an optically transparent lower substrate wafer. FIG. 6B is a front cross-sectional view showing a state in which an adhesive is applied to the substrate shown in FIG. 7A and an optically transparent upper substrate wafer is placed thereon, and FIG. 7C is an optically transparent upper substrate. FIG. 6 is a perspective view showing a state where up to the wafer is installed and the adhesive is cured by UV light.

FIG. 18 is a schematic configuration diagram showing an example of an optical pickup including a hologram laser unit manufactured by using the polarization beam splitting element of Example 5.

19A and 19B are explanatory views of a method for manufacturing the polarization beam splitting element of Example 6, where FIG. 19A is a perspective view showing a state in which an optically transparent lower substrate wafer is installed on a spin table, and FIG. 19B is an orientation flat. Top view of an optically transparent lower substrate wafer with a film and an organic birefringent film having orientation flats on three sides, (c) shows a state in which an adhesive is applied on the optically transparent lower substrate wafer and spread to a certain thickness. It is a perspective view shown.

FIG. 20 is an explanatory diagram of the method for manufacturing the polarization beam splitting element of Example 6, in which (a) aligns a part of the orientation flat portion of the optically transparent lower substrate wafer with the orientation flat portion of the organic birefringent film. Then, a top view showing a state in which the organic birefringent film is attached on the optically transparent lower substrate wafer, (b) shows that the organic birefringent film is placed on the adhesive and the adhesive is cured by UV light. It is a perspective view showing a situation.

21 (a) and 21 (b) are explanatory views of a method for manufacturing a polarization beam splitting element of Example 6, wherein (a) is a substrate shown in FIG. 20 (b) coated with an adhesive, and an optically transparent upper substrate wafer is applied thereon. FIG. 3B is a front sectional view showing the installed state, and FIG. 6B is a perspective view showing the installed state up to the optically transparent upper substrate wafer and curing the adhesive by UV light.

22A and 22B are explanatory diagrams of a method for manufacturing the polarization beam splitting element of Example 7, wherein FIG. 22A is a perspective view showing a state in which an optically transparent lower substrate wafer is set on a spin table, and FIG. 22B is an orientation flat. FIG. 3C is a top view of the optically transparent lower substrate wafer having the above and the organic birefringent film, and FIG. 7C is a perspective view showing a state in which an adhesive is applied on the optically transparent lower substrate wafer and the film is extended to a constant thickness.

FIG. 23 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 7, in which (a) aligns a part of the orientation flat part of the optically transparent lower substrate wafer with the orientation flat part of the organic birefringent film. And (b) is a top view showing a state in which an organic birefringent film is installed on an optically transparent lower substrate wafer, and (b) is an organic birefringent film installed on an adhesive.
A perspective view showing a state where the adhesive is cured by V light,
FIG. 3C is a top view schematically showing a state in which a diffraction grating is formed on the birefringent film attached on the optically transparent lower substrate wafer.

FIG. 24 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 7, (a) applying an adhesive to the substrate shown in (c) of FIG. 23, and applying an optically transparent upper substrate wafer thereon. FIG. 3B is a front sectional view showing the installed state, and FIG. 6B is a perspective view showing the installed state up to the optically transparent upper substrate wafer and curing the adhesive by UV light.

FIG. 25 is a schematic configuration diagram showing an example of an optical pickup including a hologram laser unit manufactured by using the polarization beam splitting element of Example 7.

26A and 26B are explanatory views of the method for manufacturing the polarization beam splitting element of Example 8, in which FIG. 26A is a perspective view showing a state in which an optically transparent lower substrate wafer is installed on a spin table, and FIG. 26B is an orientation flat. Top view of the optically transparent lower substrate wafer and the organic birefringent film having the above, (c) is a perspective view showing a state in which an adhesive is applied on the optically transparent lower substrate wafer and extended to a constant film thickness, (d) FIG. 3 is a perspective view showing a state in which an optically anisotropic film is placed on an adhesive and the adhesive is cured by UV light.

FIG. 27 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 8, wherein (a) is a substrate shown in FIG. 26 (d) coated with an adhesive, and an optically transparent upper substrate wafer is applied thereon. FIG. 3B is a front sectional view showing the installed state, and FIG. 6B is a perspective view showing the installed state up to the optically transparent upper substrate wafer and curing the adhesive by UV light.

28 is a schematic configuration diagram showing an example of an optical pickup including a hologram laser unit manufactured using the polarization beam splitting element of Example 8. FIG.

29A and 29B are explanatory views of the method for manufacturing the polarization beam splitting element of Example 9, wherein FIG. 29A is a perspective view showing a state in which an optically transparent lower substrate wafer is installed on a spin table, and FIG. 29B is an orientation flat. FIG. 3C is a top view of the optically transparent lower substrate wafer having the above and the organic birefringent film, and FIG. 7C is a perspective view showing a state in which an adhesive is applied on the optically transparent lower substrate wafer and the film is extended to a constant thickness.

FIG. 30 is an explanatory diagram of the method for manufacturing the polarization beam splitting element of Example 9, in which (a) aligns a part of the orientation flat portion of the optically transparent lower substrate wafer with the orientation flat portion of the organic birefringent film. Then, a top view showing a state in which an organic birefringent film is pasted on an optically transparent lower substrate wafer, (b) shows an optically anisotropic film placed on the adhesive, and the adhesive is cured by UV light. A perspective view showing the state of

FIG. 31 is an explanatory view of the method for manufacturing the polarization beam splitting element of Example 9, (a) applying an adhesive to the substrate shown in FIG. 30 (b), and applying an optically transparent upper substrate wafer on it. FIG. 3B is a front sectional view showing the installed state, and FIG. 6B is a perspective view showing the installed state up to the optically transparent upper substrate wafer and curing the adhesive by UV light.

[Explanation of symbols]

1: Polarization separating element 2: Polarization separating element Diffraction grating part 3: Optically transparent lower substrate 4: Adhesive layer (A) 5: Optically anisotropic material such as organic birefringent film 6: Adhesive layer (B) 7: Optically transparent upper substrate 8: Adhesive 9: Cap 10: λ / 4 plate 11: Semiconductor laser 12: Light receiving element 13: Stem 14: Lead 15: Polarization separating element 16 composed of a plurality of wafers before being cut into each element : Alignment pin 17: Spin table 18 with alignment pin: First substrate 19: Second substrate 20: Adhesive (A) 21: Spin table without alignment pin 22: Optically transparent lower substrate wafer 23 , 33, 34: Optically anisotropic film such as organic birefringent film 24: Adhesive (B) 25: Optically transparent upper substrate wafer 26: Spacer 27: Reduction projection exposure device 28: Wafer transfer tray 29: CD camera 30: collimating lens 31: objective lens 32: optical disk

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) G11B 7/22 G11B 7/22 (72) Inventor Shuichi Hikiji 1-3-6 Nakamagome, Ota-ku, Tokyo・ In stock company Ricoh (72) Inventor Akishige Murakami 1-3-6 Nakamagome, Ota-ku, Tokyo ・ In stock company Ricoh (72) Inventor Tsuyoshi Suzuchi 1-3-6 Nakamagome, Ota-ku, Tokyo・ Inside Ricoh Co., Ltd. (72) Inventor Koji Mori 1-3-6 Nakamagome, Ota-ku, Tokyo ・ F-term inside Ricoh Co., Ltd. (reference) 2H049 AA03 AA13 AA33 AA37 AA42 AA57 AA64 BA05 BA42 BA45 BA47 BB42 BC01 BC14 BC21 CA05 CA09 CA15 CA28 5D119 AA01 AA38 AA40 AA43 BA01 BB01 BB02 BB03 DA01 DA05 FA05 FA30 JA12 JA14 JA64 JA65 NA05 5D789 AA01 AA38 AA40 AA43 BA01 BB01 BB02 BB03 DA01 DA05 FA05 FA30 JA12 JA14 JA64 JA 65 NA05

Claims (24)

[Claims] 1. A method of manufacturing a polarization separation element, which comprises a step of separating a plurality of polarization separation elements made of an optically anisotropic film having an uneven diffraction grating on an optically transparent substrate wafer into respective elements, After attaching the optically anisotropic film to the optically transparent substrate wafer, in the step of forming a diffraction grating, an ordinary ray direction or an extraordinary ray direction of the optically anisotropic film is detected. A method for manufacturing a polarization separation element. 2. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the optically anisotropic film on the optically transparent substrate wafer has an ordinary ray direction or an extraordinary ray direction. A method of manufacturing a polarization beam splitting element, which has an orientation flat indicating one of the directions. 3. The method for producing a polarization beam splitting element according to claim 1, wherein one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film and an orientation flat of the optically transparent substrate wafer. A method for producing a polarization separation element, which comprises using an optically transparent substrate wafer to which an optically anisotropic film is attached so that the directions are substantially the same. 4. The method for producing a polarization beam splitting element according to claim 1, 2 or 3, wherein the optically transparent substrate wafer to which the optically anisotropic film is attached is usually made of the optically anisotropic film. A method for producing a polarization separation element, wherein one of a light ray direction and an extraordinary ray direction and an orientation flat direction of the optically transparent substrate wafer are parallel to each other with an accuracy of 2 ° or less. 5. The method for producing a polarization beam splitting element according to claim 1, wherein the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed by the optically transparent substrate. A method for manufacturing a polarization beam splitting device, which is characterized by detecting from an angle deviation from a direction of a wafer orientation flat. 6. The method for manufacturing a polarization beam splitting element according to claim 1, wherein an ordinary ray direction or an extraordinary ray direction of the optically anisotropic film on the optically transparent substrate wafer is detected. Is performed during the lithography process, which is one of the processes for forming the diffraction grating, before the process, or during the transportation to the process. 7. The method of manufacturing a polarization beam splitting element according to claim 1, wherein the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed by an exposure device or reduction projection. A method of manufacturing a polarization beam splitting element, which is characterized in that detection is performed using an exposure apparatus. 8. A method of manufacturing a polarization separation element, which comprises a step of separating a plurality of polarization separation elements made of an optically anisotropic film having an uneven diffraction grating on an optically transparent substrate wafer into respective elements, A method for producing a polarization beam splitting element, comprising detecting an ordinary ray direction or an extraordinary ray direction of the optically anisotropic film before attaching the optically anisotropic film to the optically transparent substrate wafer. 9. The method for manufacturing a polarization beam splitting element according to claim 8, wherein the optically anisotropic film has an orientation flat indicating either the ordinary ray direction or the extraordinary ray direction. A method for manufacturing a polarization separation element. 10. The method for producing a polarization separation element according to claim 8, wherein the optically anisotropic film is rotated after detecting one of the ordinary ray direction and the extraordinary ray direction of the optically anisotropic film. Then, after that, an optically anisotropic film is attached to an optically transparent substrate wafer, and a method for producing a polarization beam splitting element. 11. The method for manufacturing a polarization beam splitting element according to claim 8, 9 or 10, wherein the detection of the ordinary ray direction or the extraordinary ray direction of the optically anisotropic film is performed by using an orientation flat of an optically transparent substrate wafer. A method for manufacturing a polarization beam splitting element, characterized by detecting from an angle deviation from a direction. 12. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the optically transparent substrate wafer to which the optically anisotropic film is attached has a substantially constant thickness. A method for producing a polarization beam splitting element, wherein the polarization beam splitting element is bonded so as to form an adhesive layer. 13. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the optically transparent substrate wafer having the optically anisotropic film adhered thereto rotates a spin table. A method of manufacturing a polarization beam splitting element, which is manufactured by adjusting the film thickness of the adhesive agent. 14. The method for producing a polarization beam splitting element according to claim 1, wherein the optically transparent substrate wafer to which the optically anisotropic film is attached is produced optically. After the adhesive applied on the transparent substrate wafer has a constant film thickness, the optically anisotropic film is placed on the adhesive, and the spin table is rotated again to make the adhesive have a constant film thickness. A method for producing a characteristic polarization separation element. 15. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the optically transparent substrate wafer to which the optically anisotropic film is attached is produced by an optical method. A method for producing a polarization separation element, which is characterized by comprising a step of aligning a part or all of a line segment showing an orientation flat of a transparent substrate wafer with a position of a line segment of an optically anisotropic film. 16. The method for manufacturing a polarization separation element according to claim 1, wherein the optically anisotropic film has a separable protective film attached thereto. A method for manufacturing a polarization beam splitting element, characterized by using. 17. The polarization separating element according to claim 1, wherein an organic birefringent film is used as the optically anisotropic film. Of manufacturing. 18. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the polarization beam splitting element is an optically transparent lower substrate, a lower adhesive layer (adhesive layer A), and an optical transparent lower substrate. An anisotropic film, an upper adhesive layer (adhesive layer B), and an optically transparent upper substrate, wherein one of the optically transparent lower substrate and the optically transparent upper substrate is the optically transparent substrate wafer. And a method for manufacturing a polarization separation element. 19. The method for manufacturing a polarization beam splitting element according to claim 18, wherein either one of the refractive index in the ordinary ray direction and the refractive index in the extraordinary ray direction of the optically anisotropic film and the optically anisotropic film thereof. Polarization separation characterized in that the refractive index of the adhesive layer B that fills the diffraction grating formed in 1) and the refractive index of the adhesive layer A of the optically anisotropic material on the side where the diffraction grating is not formed are substantially the same. Manufacturing method of device. 20. The method of manufacturing a polarization beam splitting element according to claim 18 or 19, wherein at least one of the lower surface of the optically transparent lower substrate and the upper surface of the optically transparent upper substrate is provided with an antireflection film. A method for manufacturing a polarization separation element, characterized by using. 21. A method of manufacturing a polarization beam splitting element according to claim 1, wherein the adhesive layer in the polarization beam splitting element according to any one of claims 1 to 17 or 18. 20. As an adhesive used for producing the adhesive layers A and B in the polarization beam splitting element according to any one of 20 to 20, an epoxy adhesive, an acrylic adhesive or a rubber which is photosensitive and has a large elastic force. A method for producing a polarization beam splitting element, characterized by using a system adhesive. 22. A polarization separation element according to any one of claims 1 to 21, wherein the polarization separation element has an optically anisotropic film having an uneven diffraction grating provided on an optically transparent substrate. A polarization beam splitting element manufactured by using a method for manufacturing a device. 23. A hologram laser unit in which a polarization separating element is integrated with a laser unit having a semiconductor laser and a light receiving element, which is produced using the polarization separating element according to claim 22. 24. An optical pickup for recording, reproducing or erasing information on an optical information recording medium, which is produced by using the polarization separation element according to claim 22 or the hologram laser unit according to claim 23. An optical pickup featuring.