JP2010210850A - Method of manufacturing optical article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical article having uniform thickness of optical adhesive. <P>SOLUTION: The method of manufacturing the optical article includes a step of sticking a translucent member 14 and a crystalline substrate 17 mutually by using the adhesive 18 having optical adhesive liquids 181, 182, a mixing step of dispersing spacer particles 131, 132 into the optical adhesive liquids 181, 182, a dropping step of dropping the optical adhesive liquids 181, 182 containing the dispersed spacer particles 131, 132, and a nipping and holding step of pressing the crystalline substrate 17 against the translucent member 14, pressing and spreading the optical adhesive liquids 181, 182, and nipping and holding them. In the mixing step, various spacer particles 131, 132 being different in compression displacement load from each other are used and are mixed with the optical adhesive liquids 181, 182 depending kind of these different spacer particles 131, 132. In the dropping step, the optical adhesive liquids 181, 182 thus prepared are dropped into a central part A and regions other than the central part A of the translucent member 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a polarization conversion element and other optical articles.

In optical pickups, liquid crystal projectors, and other devices, optical articles formed by sandwiching an optical thin film between a plurality of translucent members are used.
As such an optical article, a light-emitting surface of the light-polarizing separation film of these light-transmitting members is sequentially laminated by sandwiching a light-polarizing separation film between two light-transmitting members each provided with a reflective film therein. A polarization separation element (PS conversion element) having a quartz phase plate on the side is known.

  For example, a polarization separation film is formed on one surface of the first light transmissive member, a reflective film is formed on the other surface of the first light transmissive member, and one of the second light transmissive members is formed. A quartz phase plate, which is a phase difference plate, is bonded to the surface, and then the first light transmissive member and the second light transmissive member are disposed so that the polarization separation film of the first light transmissive member and the crystal phase plate face each other. There is a conventional example (see Patent Document 1 and Patent Document 2) in which an optical member is laminated and bonded. The quartz plate is processed into a thin piece so that the polarization conversion efficiency of the PS conversion element is optimized. In this thin piece processing, the quartz phase plate is polished by using the other surface of the second translucent member bonded to the quartz phase plate as a reference plane.

In bonding such optical articles, an optical adhesive is used particularly when a portion (main surface) including an effective region through which light is transmitted is bonded. This optical adhesive is an adhesive whose material is designed so as to obtain practically desired optical characteristics when cured by ultraviolet irradiation, heating, or the like.

Patent 4080198 JP 2007-206225 A

In the conventional examples shown in Patent Document 1 and Patent Document 2, high-precision quartz plate thickness processing is required to obtain target optical characteristics. However, since a liquid adhesive is used when adhering the quartz plates, the thickness of the adhesive may be uneven if the quartz plates are not adhered with uniform pressure. For this reason, when the quartz plate is processed into a thin piece using the surface of the translucent member as a reference surface, there is a problem that the thickness of the quartz plate cannot be made uniform due to the non-uniformity of the thickness of the adhesive.
Further, the uneven thickness of the quartz plate causes a decrease in the polarization conversion efficiency of the PS conversion element, and thus there is a problem that it is difficult to manufacture a PS conversion element having a high polarization conversion accuracy. .

  The objective of this invention is providing the manufacturing method of the optical article with the uniform thickness of an adhesive agent.

[Application Example 1]
The manufacturing method of an optical article in this application example is a manufacturing method of an optical article in which main surfaces of a plurality of translucent members are bonded to each other via an optical adhesive, and the optical adhesive has spacer particles dispersed therein. A dropping step formed from an optical adhesive liquid and dropping the optical adhesive liquid onto a plurality of dropping points on a main surface of at least one of the translucent members; and main surfaces of the plurality of translucent members Holding the optical adhesive liquid between the main surfaces by pressing them together, and sandwiching the spacer particles having different compressive displacement loads into the liquid of the optical adhesive for each type. A plurality of types of dispersed optical adhesive liquids are prepared, and in the dropping step, the plurality of types of optical adhesive liquids are respectively dropped onto a plurality of dropping locations on the main surface.

In this application example having this configuration, a plurality of types of optical adhesive liquids in which spacer particles having different compressive displacement loads are dispersed are respectively dropped onto a plurality of dropping portions. When the main surfaces are pressed against each other in the sandwiching step, the pressure is transmitted while holding the end portion of the translucent member in a normal case. Therefore, the strength of the pressing locally occurs on the main surface. If spacer particles with a large compressive displacement load are dropped on the location of the main surface where the pressure is transmitted strongly, the deformation of the spacer particles at that location will be reduced and the distribution of the adhesive thickness in the main surface will be uniform. be able to.
Specifically, when only the spacer particles 13 having a small compressive displacement load are used, a part of the spacer particles 13 to which a large pressing force is applied is locally deformed and the thickness of the adhesive 18 becomes uneven ( (See FIG. 10). However, in this application example, there is no such fear, and even if a sufficient pressing force is applied, the thickness of the adhesive can be made uniform over the entire main surface.

  On the contrary, if the pressing force is insufficient, a portion where the spacer particles overlap in the thickness direction of the adhesive is generated, and the thickness of the adhesive is not uniform. Accordingly, an excessive pressing force tends to be applied in the clamping process. However, in this application example, since spacer particles with a large compressive displacement load are included, the spacer particles with a large compressive displacement load prevent excessive deformation even when an excessive pressing force is applied. Can be.

Therefore, it is possible to stably uniform the thickness of the entire adhesive by applying a slightly large pressing force without controlling the appropriate pressing force to attach the translucent member and the crystalline substrate. Can do.
Therefore, in the manufacturing method of the optical article in this application example, the thickness of the adhesive is prevented from being uneven, and the accuracy of the post-polishing thickness of the quartz phase plate or the like is improved in the next thin piece processing, so that an optical having desired optical characteristics is obtained. Articles can be obtained easily and accurately.

[Application Example 2]
In the method of manufacturing an optical article according to this application example, the plurality of dropping portions of the plurality of types of optical adhesive liquids include at least one central portion on the main surface of the translucent member, the central portion, and the main surface. It is preferable to be a plurality of locations in an intermediate region with the upper outer edge.

  In this application example having this configuration, in the sandwiching step in which the principal surfaces of the plurality of translucent members are pressed against each other to spread and sandwich the optical adhesive liquid between the principal surfaces, Even if different pressing forces are transmitted to multiple points in the intermediate area with the outer edge of the surface, the thickness of the formed adhesive can be made uniform over the entire main surface, so that The translucent substrate provided can be processed into a thin piece with a uniform thickness.

[Application Example 3]
In the method of manufacturing an optical article in this application example, the plurality of types of optical adhesive liquids are configured by a first optical adhesive liquid and a second optical adhesive liquid, and the first optical adhesive liquid is a second optical adhesive liquid. The compressive displacement load is larger than that of the optical adhesive liquid, and the second optical adhesive liquid is dropped onto the central portion on the main surface, and a plurality of locations in the intermediate region between the central portion and the outer edge portion on the main surface It is preferable that the first optical adhesive liquid is dropped.

In this application example of this configuration, since the adhesive liquid is dropped on a concentric circle centering on the central portion of the main surface of the translucent member, when the main surfaces of the translucent member are pressed, the outer edge portion A plurality of types of adhesive liquids spread between the main surfaces toward the surface. For this reason, the plurality of types of spacer particles spreads wet around the central portion between the main surfaces together with the adhesive.
For this reason, the spacer particles dispersed in the adhesive liquid dropped on the central portion of the main surface are distributed in the vicinity of the central portion of the main surface in the adhesive, and in an intermediate region between the central portion on the main surface and the outer edge portion. The spacer particles dispersed in the dropped adhesive are distributed near the outer edge of the main surface.
Therefore, the distribution between the main surfaces of the spacer particles can be easily controlled by the position where the adhesive liquid is dropped on the main surface of the translucent member.
In the sandwiching process, when the main surfaces of the translucent member are pressed with each other, the main surface is an area where light passes through as an optical component, and because it dislikes the occurrence of dirt and scratches, the pressure is applied to the outer edge part rather than the main surface. I often communicate. Therefore, since the pressing force point is disposed near the outer edge portion, the spacer particles are easily deformed. Accordingly, by dropping an optical adhesive liquid in which spacer particles having a large compressive displacement load are dispersed into an intermediate region between the central portion on the main surface and the outer edge portion, an intermediate region between the central portion on the main surface and the outer edge portion is dropped. The deformation of the spacer particles is small, and the thickness of the adhesive on the entire main surface has a uniform distribution.

[Application Example 4]
In the manufacturing method of an optical article in this application example, it is preferable that an optical adhesive liquid in which spacer particles having practically the same refractive index as the optical adhesive are dispersed is dropped in a central portion on the main surface. .

In this application example of this configuration, since the adhesive liquid in which spacer particles having substantially the same refractive index as the adhesive are dispersed is dropped at the center of the main surface of the translucent member, when the translucent members are bonded together Then, spacers having a refractive index equivalent to that of the adhesive are distributed in the central portion of the main surface.
For this reason, the optical characteristics of the spacer particles and the adhesive are substantially the same. Therefore, when light passes through this central portion, even if this light passes through the spacer particles, it is optically equivalent to the light that passes through the adhesive. Characteristic. In general, a lot of light passes through the center of the main surface.
In other words, even if an adhesive mixed with spacer particles is used, a large number of areas where light can be transmitted are distributed with the sparser particles that can obtain the same optical characteristics, and the thickness of the optical adhesive is affected. By distributing spacer particles that are easy to control the pressure in the middle region between the central portion and the outer edge portion, an optical article that achieves both the optical characteristics of transmitted light and the uniform distribution on the main surface of the optical adhesive is obtained. be able to.

[Application Example 5]
In the manufacturing method of the optical article in this application example, the translucent member is a glass substrate and a quartz phase plate, and in the optical article, the glass substrate and the quartz phase plate sandwich the optical adhesive liquid. The first laminated body laminated in this manner and the second laminated body in which the polarization separation film and the reflective film are formed on the main surface of the glass substrate are preferably connected to each other.

  In this application example of this configuration, the optical adhesive can be adhered to the main surface with a uniform thickness, so even if the glass surface of the first laminate is processed as a reference surface, the quartz phase plate has a uniform thickness. Can be manufactured. Therefore, a polarization conversion element having high polarization conversion accuracy can be manufactured.

The schematic diagram of the PS conversion element in this embodiment. Schematic which shows the state which dripped the adhesive liquid on the glass substrate. Schematic for demonstrating the method of bonding the glass substrate and quartz phase plate in this embodiment. The schematic diagram for demonstrating the method of bonding the glass substrate and quartz phase plate in this embodiment. Schematic for demonstrating the thin piece processing process of the crystal phase plate in this embodiment. Schematic for demonstrating the method to connect the 1st laminated body and 2nd laminated body in this embodiment. The perspective view which shows the laminated body which connected the 1st laminated body and the 2nd laminated body in this embodiment. The schematic diagram for demonstrating the cutting | disconnection of the laminated body in this embodiment. The schematic diagram for demonstrating the cutting | disconnection of the laminated body in this embodiment. Schematic explaining the bonding process at the time of using only spacer particles with a small compressive displacement load.

[Configuration of optical system]
FIG. 1 is a schematic diagram of a polarization conversion element in the present embodiment.
As shown in FIG. 1, the PS conversion element 1 has a light incident surface 11 and a light exit surface 12 that are substantially parallel to each other, and a plurality of interfaces provided on the light exit surface 12 at a plurality of interfaces with an angle of 45 degrees. Provided between a glass substrate (hereinafter referred to as a glass substrate) 14 that is a translucent member, polarization separation films 15 and reflection films 16 that are alternately provided at a plurality of interfaces, and between the polarization separation film 15 and the glass substrate 14. A crystal substrate (hereinafter referred to as a crystal plate) 17 that is a crystal phase plate, and a glass substrate 14, a polarization separation film 15, a reflective film 16, and an adhesive 18 provided at the interface of the crystal substrate 17 are provided.

The glass substrate 14 is formed from a prismatic member having a triangular cross section or a parallelogram-shaped cross section, and the polarization separation films 15 and the reflective films 16 are alternately arranged on the slopes constituting the interface.
The glass substrate 14 constitutes an optical article in the present embodiment. Examples of the material constituting the glass substrate 14 include optical glass such as BK7, white plate glass, borosilicate glass, and blue plate glass.

Two types of adhesive liquids 181 and 182 are used for the adhesive 18. Two types of spacer particles 131 and 132 are dispersed in these adhesive liquids 181 and 182, respectively. As the spacer particles 131 and 132, for example, particles having different compressive displacement loads and refractive indexes may be used.
Specifically, a spacer particle 131 having a refractive index equivalent to that of the adhesive 18 and 10% smaller than the spacer particle 132 by a compressive displacement load is used. On the other hand, the spacer particles 132 may be those having a 10% larger compressive displacement load than the spacer particles 131.

The spacer particles 131 and 132 have a particle size of about 2 μm to 10 μm, and those having the same particle size are used.
The thickness of the adhesive 18 is practically the same as the particle diameters 131 and 132 of spacer particles. For the adhesive liquids 181 and 182 that form the adhesive 18, an ultraviolet curable adhesive can be used. At this time, the adhesive liquids 181 and 182 preferably have the same refractive index, more preferably the same material, that is, the same feature.
Further, the concentration of the spacer particles 131 and 132 dispersed in the two types of adhesive liquids 181 and 182 is preferably higher in the adhesive liquid 181 than in the adhesive liquid 182.

The polarization separation film 15 is formed of a dielectric multilayer film, and separates an incident light bundle (random polarized light) into an S-polarized partial light beam (S-polarized light) and a P-polarized partial light beam (P-polarized light), It has a function of reflecting S-polarized light and transmitting P-polarized light.
Refraction in comprising a mixture of 3: dielectric multilayer film, for example, a low refractive index layer made of SiO _2, a high refractive index layer made of MgF _2, the weight ratio of _La 2 _{O 3} and _Al 2 _{O 3} is 1 The rate layer can be exemplified by a multilayer film formed in a predetermined order and optical film thickness.

The reflective film 16 is formed of a dielectric multilayer film or a metal film, and has a function of reflecting S-polarized light incident on the reflective film 16 as it is. The multilayer film constituting the reflection film 16 can be exemplified by a multilayer film in which low refractive index layers made of SiO ₂ and high refractive index layers made of TiO ₂ are alternately formed in a predetermined order and optical film thickness.

The quartz substrate 17 is a strip-shaped half-wave plate having a thickness of, for example, 28 μm, and is closely fixed to the light exit surface 12 side of the polarization separation film 15.
The quartz substrate 17 is a single mode wavelength plate formed of quartz made of a single crystal of SiO ₂ , and this quartz crystal may be an artificial quartz crystal or a natural quartz crystal. Moreover, a double mode wavelength plate may be used.
As shown in FIG. 1, the PS conversion element 1 includes a first laminate 1 </ b> A having a glass substrate 14, an adhesive 18 and a quartz substrate 17 as a unit, a polarization separation film 15, a glass substrate 14, and a reflection film 16. It has a repeating structure in which the second laminate 1B as one unit is repeatedly connected.

The manufacturing method of the optical article of this embodiment will be described.
[Formulation process]
An adhesive is put into a mixing and stirring tank (not shown) equipped with a stirring device having a stirring blade. Thereafter, the spacer is put into the mixing and stirring tank while stirring with a stirring device. At this time, the spacers are added in small amounts so as not to become lumps. After the addition, stirring is continued until the spacers are uniformly dispersed. More preferably, degassing (defoaming) is performed at the time of mixing.

[Drip process]
FIG. 2 is a schematic view showing a state where an adhesive liquid is dropped onto a glass substrate.
The rectangular glass substrate 14 has a light transmission part A as a center part away from the outer edge part. The light transmitting portion A is a portion through which main light is transmitted in a PS conversion element (not shown).
In the dropping step, the adhesive liquid 181 is dropped at the center of the light transmitting portion A, and the adhesive liquid 182 is dropped at the four corners of the rectangular glass substrate 14 near the outer edge portion.
At this time, as a method of dripping the adhesive liquids 181 and 182, the adhesive liquids 181 and 182 may be dripped at a plurality of locations at once using a dispenser equipped with a plurality of charge nozzles. Alternatively, the adhesive liquid 181 may be dropped at the center of the light transmitting portion A and the adhesive liquid 182 may be dropped at an intermediate region between the center portion and the outer edge portion.
The spacer particles 131 and 132 are dispersed at a concentration of 0.1 wt% or more and less than 3 wt% with respect to the adhesive liquids 181 and 182, respectively.

[Clamping process]
As shown in FIG. 3, the rectangular pedestal 21 has four engaging pins 22 erected. A flat glass substrate 14 is placed on the pedestal 21, and adhesive liquids 181 and 182 are dropped on the main surface of the glass substrate 14 to form a support 14A. A quartz crystal is formed on the support 14A. The substrate 17 is overlaid. Thereafter, an appropriate pressure is applied to the adhesive 18 by placing the weight plate 23 on the quartz substrate 17. The weight plate 23 is provided with an insertion hole 24 at a position corresponding to the engagement pin 22, and the distance from the base 21 is reduced while the engagement pin 22 is inserted into the insertion hole 24. For this reason, the weight board 23 is restricted from rotating with respect to the base 21.
Therefore, when the glass substrate 14 and the quartz substrate 17 are pressed, the glass substrate 14 and the quartz substrate 17 do not shift.

FIG. 4 is a schematic diagram for explaining a method of bonding a glass substrate and a crystal substrate in the present embodiment.
As shown in FIG. 4A, an adhesive liquid 181 is applied to the center of the light transmitting portion A on the glass substrate 14 in which only one light transmitting portion A (see FIG. 2) is enlarged, and its center and outer edge portion. The adhesive liquid 182 is dropped on the intermediate region of the substrate, and the quartz substrate 17 is overlaid thereon. At this time, as shown in FIG. 4B, the adhesive liquid 181 wets and spreads toward the outer edge portion when the quartz substrate 17 is pressed. On the other hand, the adhesive liquid 182 spreads wet from the intermediate region toward the outer edge.
Here, since the amount of the adhesive liquid 181 dropped more than that of the adhesive liquid 182, as the crystal substrate 17 is pressed and brought closer to the glass substrate 14, the adhesive liquid 181 wets toward the outer edge portion. The spreading counteracts the wetting and spreading of the adhesive liquid 182 toward the center, and pushes the adhesive liquid 182 toward the outer edge.

4C, in the adhesive 18, the adhesive liquid 181 is located at the center of the light transmission part A, and the adhesive liquid 182 is distributed at a position close to the outer edge part of the light transmission part A. It becomes. That is, the spacer particles 131 are distributed in the center of the light transmitting portion A, and the spacer particles 132 are distributed in the intermediate region between the light transmitting portion A and the outer edge portion.
Further, at this time, the spacer particles 131 and 132 are arranged in a single layer without overlapping in the thickness direction of the adhesive 18. That is, the adhesive 18 is practically substantially the same as the particle size of the spacer particles 131 and 132 sandwiched between the glass substrate 14 and the quartz substrate 17. For this reason, the adhesive 18 is formed with a uniform thickness, and thickness unevenness hardly occurs.

[Sheet processing process]
The thin piece processing step will be described with reference to FIG.
FIG. 5 is a schematic view for explaining the thin-film processing step of the quartz crystal substrate in the present embodiment.
As shown in FIG. 5 (A), the thin piece processing apparatus has a flat support plate 31 and a sliding surface 32A parallel to the support surface 31A of the support plate 31, and with respect to the support surface 31A. Thus, an apparatus having a grindstone 32 operable to draw a circle with the sliding surface 32A kept parallel is used.
The first laminate 1A is supported on the support plate 31 so that the glass substrate 14 is in contact with the support surface 31A. On the other hand, the quartz substrate 17 is brought into contact with the sliding surface 32A at a predetermined pressure from above. Then, the quartz substrate 17 is slid with the sliding surface 32 </ b> A as the grindstone 32 moves so as to draw a circle. Thereby, as shown in FIG. 5B, the quartz substrate 17 is ground or polished to be processed into a thin piece. Thereby, 1A of 1st laminated bodies are obtained.

[Laminated body forming step]
A laminated body formation process is demonstrated based on FIG. 6 and FIG.
FIG. 6 is a schematic diagram for explaining a method of laminating the first laminate and the second laminate in the present embodiment. FIG. 7 is a perspective view showing a laminate in which the first laminate and the second laminate in the present embodiment are laminated.
The 2nd laminated body 1B is produced by vapor-depositing the polarization separation film 15 and the reflective film 16 on the plane of another glass substrate 14, respectively. As shown in FIG. 6, the first laminated body 1 </ b> A and the second laminated body 1 </ b> B are arranged so as to be shifted in the horizontal direction so that the lower ends of the plates abut on the plate P inclined at 45 ° with respect to the plane of the base 21. .
Thereby, as shown in FIG. 7, the laminated body 10 in which the first laminated body 1A and the second laminated body 1B are shifted by 45 ° is formed.

[Cutting process]
A cutting process for cutting the laminated body 10 into a predetermined shape will be described with reference to FIGS.
FIG. 8 is a schematic diagram for explaining the cutting of the laminate in the present embodiment. FIG. 9 is a schematic diagram for explaining the cutting of the laminate in the present embodiment.
As shown in FIG. 8, the first laminated body 1A and the second laminated body 1B that are laminated are parallel to the arrangement direction of the plate P (see FIG. 6) with respect to the optical element plane, that is, with respect to the plane of the optical element. And cut at predetermined intervals along a direction L of 45 °. Thereby, the end surface of the block 19 becomes a parallelogram.

  After cutting, as shown in FIG. 9, the end portions of the blocks 19 are aligned and stacked vertically, and both left and right side portions are trimmed. In other words, the upper edges of the polarization separation film 15 or the reflection film 16 located on the leftmost side are connected to each other, and the lower edges of the polarization separation film 15 or the reflection film 16 located on the rightmost side are connected to the plane of the block 19. The PS conversion element 1 (see FIG. 1) is obtained by cutting along the direction V perpendicular to the direction.

In the present embodiment having the above-described configuration, the following operational effects can be achieved.
(1) In this embodiment, since a plurality of types of adhesive liquids 181 and 182 in which spacer particles 131 and 132 having different compressive displacement loads are dispersed are used, the glass substrate 14 and the quartz substrate 17 are pressed with a strong pressure. At this time, since a material having a large compressive displacement load is not easily deformed, the distribution of the thickness of the adhesive 18 in the main surface can be made uniform.
Specifically, when only the spacer particles 131 having a small compressive displacement load are used, if a large pressing force is applied, a part of the spacer particles 131 may be locally deformed and the thickness of the adhesive 18 may become uneven. There is. However, if a plurality of types of adhesive liquids 181 and 182 in which spacer particles 131 and 132 having different compressive displacement loads are dispersed are dropped onto a plurality of locations and then pressed and sandwiched, excessive pressing force may be applied locally. The distribution of the thickness of the adhesive 18 in the main surface is uniform.
On the contrary, if the pressing force is insufficient, the spacer particles 131 remain overlapped in the thickness direction of the adhesive 18 and the thickness of the adhesive 18 becomes non-uniform.
Therefore, even if the appropriate strong and weak pressing force is set for each of the spacer particles 131 and 132 and the glass substrate 14 and the quartz substrate 17 are not bonded to each other, by applying a slightly large pressing force, the adhesive 18 can be stably formed. The thickness in the main surface can be made uniform.

(2) In this embodiment, after the support 14A and the quartz substrate 17 are bonded together, the quartz substrate 17 is processed into a thin piece. At this time, since the main surface distribution of the thickness of the adhesive 18 formed when the support 14A and the quartz substrate 17 are bonded together is uniform, the quartz substrate 17 provided on the adhesive 18 is made uniform. Thin pieces can be processed to a thickness.

(3) In the present embodiment, since the adhesive liquids 181 and 182 are liquefied on a concentric circle centered on the center of the light transmitting portion A of the PS conversion element 1, this light transmission is performed when the quartz substrate 17 is pressed. Various adhesive liquids 181 and 182 spread around the part A. For this reason, the various spacer particles 131 and 132 spread out in a concentric manner around the center of the light transmission part A, similarly to the adhesive liquids 181 and 182.
For this reason, the spacer particles 131 dispersed in the adhesive liquid 181 applied to the center of the light transmission part A are distributed in the vicinity of the center of the light transmission part A in the adhesive 18 and are intermediate between the light transmission part A and the outer edge part. The spacer particles 132 dispersed in the adhesive liquid 182 dropped on the region are distributed at positions near the outer edge portion in the adhesive 18.
Therefore, the position of the spacer particles 131 and 132 when it becomes the adhesive 18 can be easily controlled by the position of dropping on the main surface of the glass substrate 14.

(4) In this embodiment, since the adhesive liquid 181 in which the spacer particles 131 having substantially the same refractive index as the adhesive 18 are dispersed is dropped at the center of the light transmitting portion A of the glass substrate 14, the quartz substrate When 17 is bonded, spacer particles 131 having a refractive index practically the same as that of the adhesive 18 are distributed in the center of the light transmitting portion A in the adhesive 18.
For this reason, since the optical characteristics of the spacer particles 131 and the adhesive 18 are substantially the same, when the light passes through the light transmitting portion A, the light passes through the adhesive 18 even if the light passes through the spacer particles 131. It will be affected by the same optical effect as the light to be transmitted. That is, even if the adhesive liquid 181 in which the spacer particles 131 are dispersed is used, equivalent optical characteristics can be obtained. Note that the liquid optical adhesive solution before the curing treatment and the cured adhesive have the same composition but different refractive indexes. In this document, in order to clarify this, the liquid adhesive before curing is described as an adhesive liquid, and the adhesive after curing is described as an adhesive.

(5) In the present embodiment, the spacer particles 131 and 132 having a low concentration of the compression displacement load have a higher concentration than the spacer particles 132 having a large compression displacement load. The ratio of the few spacer particles 131 existing in the light transmission part A is further increased, and the influence of the spacer particles 131 and 132 on the optical characteristics can be reduced.

(6) In this embodiment, the spacer particles 132 having a large compressive displacement load are dropped on the intermediate region between the center and the outer edge of the light transmitting portion A of the glass substrate 14, so that the outer edge portion of the light transmitting portion A in the adhesive 18. It is distributed at a position close to.
Therefore, even if the spacer particles 131 having a small compressive displacement load are distributed in the center, the spacer particles 132 in the middle region between the center and its outer edge can control the thickness of the adhesive 18.
Therefore, even when a large pressing force is applied for bonding, the adhesive 18 having a uniform thickness can be formed more stably and without uneven thickness.

(7) In this embodiment, when the glass substrate 14 and the quartz substrate 17 are bonded together, even if an excessive pressing force is applied, the spacer particles 132 are not easily deformed and are sandwiched between the glass substrate 14 and the quartz substrate 17. Therefore, the adhesive 18 can be easily formed with a uniform thickness. Therefore, the PS conversion element 1 having high polarization conversion accuracy can be manufactured.

  Next, the manufacturing method of the PS conversion element 1 of the present embodiment will be specifically described with reference to examples. The present invention is not limited to the following examples.

[Example]
<Adhesive formulation>
The mixture was prepared so that the concentration of the spacer particles 131 contained in the adhesive liquid 181 was 2 wt% and the concentration of the spacer particles 132 dispersed in the adhesive liquid 182 was 1 wt%, and the mixture was stirred at a rotational speed of 150 rpm for 2 hours. At this time, the dispersibility of the spacer particles 131 and 132 was good, and it was confirmed that the spacer particles 131 and 132 were uniformly dispersed in the adhesive liquids 181 and 182, respectively.

<Clamping>
0.04 g of the adhesive liquid 181 is dropped on the glass substrate 14, 0.02 g of the adhesive liquid 182 is dropped on the plurality of dropping places, and the quartz substrate 17 is placed thereon. Then, when the adhesive liquids 181 and 182 that disperse the spacer particles 131 and 132 are spread over almost the entire surface, a load of 1 kN is applied for 60 seconds. After pressurization, a UV lamp of ² mW / cm ² was irradiated for 300 seconds to cure the adhesive liquids 181 and 182 to obtain an adhesive 18.

<Adhesion evaluation>
(Evaluation of thickness unevenness)
Using a laser interferometer (Fujinon), the transmitted wavefront aberration of the glass substrate 14 and the quartz substrate 17 bonded together was measured. The measurement region is matched with the light transmission part A (see FIG. 2) when the PS conversion element 1 is used. Specifically, the outer peripheral portion 1.5 mm of the glass substrate 14 and the quartz substrate 17 is excluded.

(Evaluation of haze value)
About evaluation of haze value, it measured three times using TM double beam system haze computer HZ-2 by Suga Test Instruments Co., Ltd., and made the arithmetic average and made the result.

<Materials used>
As the glass substrate 14, the quartz substrate 17, the adhesive liquids 181 and 182 and the spacer particles 131 and 132, those shown below were used. Note that the same material was used for the adhesive liquid 181 and the adhesive liquid 182.
・ Glass substrate 14 (thickness 2.8 mm, PV = 0.001 mm or less, parallelism ± 0.001 or less)
・ Quartz substrate 17 (thickness 0.1 mm, PV = 0.001 mm or less)
・ Adhesive liquids 181 and 182 (manufactured by Sunrise MSI Co., Ltd .: PhotoBond 300, UV curable, refractive index 1.51 after curing)
Spacer particles 131 having a low 10% compressive displacement load (Nippon Shokubai: Eposter YS, 10% compressive displacement load 0.16 gf, refractive index 1.51, particle size 5.0 μm, CV value 3.5)
Spacer particles 132 having a large 10% compressive displacement load (manufactured by JGC Catalysts & Chemicals: True ball, 10% compressive displacement load 0.29 gf, refractive index 1.45, particle size 5.0 μm, CV value 1.6)

[Comparative Example 1]
In Comparative Example 1, only the adhesive liquid 182 of Example 1 was used.
Other configurations including the coating amount and the coating pattern are the same as those in the first embodiment.

[Comparative Example 2]
In Comparative Example 2, only the adhesive liquid 181 of Example 1 was used.
Other configurations including the coating amount and the coating pattern are the same as those in the first embodiment.

<Result>
The results of Examples and Comparative Examples are shown in Table 1 below.

<Summary>
In the example using the spacer particles 131 and 132, the transmitted wavefront aberration was as small as 0.51 μm, and the haze value was 0.65, which was a good value (1.0 or less). It has been found that even if this degree of haze occurs, the polarization conversion element 1 has no problem in optical characteristics.
On the other hand, in Comparative Example 1 using only the spacer particles 132, since the compressive displacement load of the spacer particles 132 is large, it is confirmed that the transmitted wavefront aberration is as small as 0.52 μm and the thickness of the adhesive 18 is uniform. It was. However, since the refractive indexes of the spacer particles 132 and the adhesive liquid 182 are different, the haze value was as large as 1.11. This is presumably because the spacer particles 132 were present in the light transmitting portion A at a considerable density.

Next, in Comparative Example 2 using only the spacer particles 131, since the compressive displacement load of the spacer particles 131 was small, the transmitted wavefront aberration was as large as 0.65 μm, and it was confirmed that the thickness of the adhesive 18 was not uniform.
However, since the refractive indexes of the spacer particles 131 and the adhesive liquid 181 are equivalent, the haze value is as small as 0.47. This is presumably because even if the spacer particles 131 are present in the light transmitting portion A at a considerable density, the optical characteristics are not affected.
From the above, it was confirmed that the PS conversion element 1 having a uniform thickness of the adhesive can be easily manufactured by utilizing the two types of spacer particles 131 and 132 each having advantages and disadvantages at appropriate positions.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In this embodiment, after the quartz substrate 17 is bonded, the thin piece is processed. However, the present invention is not limited to this, and the PS conversion element 1 may be manufactured by bonding the thin piece processed quartz substrate.
In the present embodiment, the method for manufacturing the PS conversion element 1 is used, but the present invention is not limited to this. For example, the present invention can also be applied to a retardation substrate in which a crystal substrate 17 is bonded to a glass substrate 14 using adhesive liquids 181 and 182.

In the present embodiment, the adhesive liquid 182 is applied to the four corners of the light transmission part A, but the present invention is not limited to this. For example, the adhesive liquid 182 may be applied in a circular shape on a concentric circle, or may be applied outside the concentric circle in a rectangular shape outside the adhesive liquid 181.
That is, as long as the adhesive liquid 182 is applied to the outside of the adhesive liquid 181, any may be used.

In the present embodiment, the granular spacer particles 131 and 132 are used. However, the present invention is not limited to this, and rod-shaped spacer particles 131 and 132 may be used. Further, the granular spacer particles 131 and 132 and the rod-shaped spacer particles 131 and 132 may be used in combination.
In the present embodiment, a 10% compressive displacement load is used as an index for selecting spacer particles as the compressive displacement load. This is a load value that decreases by 10% of the initial value when pressure is applied from the initial open state. However, the present invention is not limited to this, and other dynamic indicators may be used as an indicator of the compression displacement load of the spacer particles.

  The present invention can be used for projectors, polarization conversion elements used in other devices, and other optical articles.

  DESCRIPTION OF SYMBOLS 1 ... PS conversion element (optical article) 131, 132 ... Spacer particle, 14 ... Glass substrate (translucent member), 15 ... Polarization separation film, 16 ... Reflective film, 17 ... Quartz substrate (crystalline material), 18 ... Adhesives, 181, 182 ... Adhesive liquid, A ... Light transmission part (central part)

Claims (5)

A method of manufacturing an optical article, wherein main surfaces of a plurality of translucent members are bonded to each other via an optical adhesive,
The optical adhesive is formed from an optical adhesive liquid in which spacer particles are dispersed,
A dropping step of dropping the optical adhesive liquid onto a plurality of dropping points on the main surface of at least one of the translucent members;
A pressing step of pressing the main surfaces of the plurality of translucent members together to press and spread the optical adhesive liquid between the main surfaces; and
A plurality of types of optical adhesive liquids in which spacer particles having different compressive displacement loads are dispersed in the optical adhesive liquid for each type are prepared,
In the dropping step, the plurality of types of optical adhesive liquids are respectively dropped onto a plurality of dropping locations on the main surface. In the manufacturing method of the optical article according to claim 1,
The plurality of dropping portions of the plurality of types of optical adhesive liquids include a plurality of intermediate regions between at least one center portion on the main surface of the translucent member and the outer edge portion on the main portion and the central portion. A method for manufacturing an optical article, wherein the optical article is a portion. In the manufacturing method of the optical article according to claim 2,
The plural types of optical adhesive liquids are composed of a first optical adhesive liquid and a second optical adhesive liquid,
The first optical adhesive liquid has a larger compressive displacement load than the second optical adhesive liquid, and the second optical adhesive liquid is dropped on the central portion on the main surface, and the central portion on the main surface is A method for producing an optical article, comprising: dropping a first optical adhesive liquid at a plurality of locations in an intermediate region with an outer edge portion. In the manufacturing method of the optical article in any one of Claims 1-2,
A method for producing an optical article, characterized in that an optical adhesive liquid in which spacer particles having a refractive index practically the same as that of the optical adhesive is dispersed is dropped at a central portion on the main surface. In the manufacturing method of the optical article in any one of Claims 1-4,
The translucent article is a glass substrate and a crystal phase plate,
In the optical article, a first laminate in which the glass substrate and the crystal phase plate are laminated, and a second laminate in which a polarization separation film and a reflection film are formed on the main surface of the glass substrate are alternately arranged. A method for producing an optical article, which is an arrayed polarization conversion element.

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