JP5458545B2 - Method for manufacturing optical article - Google Patents

Description

  The present invention relates to a method for manufacturing an optical article including a translucent member, an adhesive layer, and an inorganic crystal material, and the optical article.

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. There is a polarization separation element (PS conversion element) provided with a crystal phase plate on the side.

For example, a first light transmissive member on which a reflective film is formed, a polarization separation conversion unit made up of a polarization phase separation film formed on the first light transmissive member and a crystal phase plate as a phase difference plate, and a second There is a conventional example (Patent Document 1) formed by sequentially superimposing and translucently adhering to each other.
Such optical articles are manufactured by various methods in which each member is bonded and fixed with an adhesive. The polarization separation / conversion unit is usually composed of a polarization separation film and a quartz phase plate, and obtains a laminate in which the first translucent member and the quartz phase plate are bonded and fixed via an adhesive. Then, the laminated body is formed to a predetermined thickness by polishing. In this case, the first light transmitting member, the adhesive, and the quartz phase plate are laminated in this order, and the quartz phase plate is polished. In general, the total thickness of the laminate was adjusted.

JP 2007-206225 A

  However, in the laminate in which the first translucent member, the adhesive, and the crystal phase plate are laminated in this order, the first translucent member and the adhesive may not have a uniform thickness. In particular, the adhesive layer tends to vary in thickness. Therefore, when the quartz phase plate is polished, a difference in thickness between the first light-transmissive member and the adhesive is reflected in the thickness of the quartz phase plate, and there is a problem that the thickness of the quartz phase plate becomes non-uniform. Furthermore, there is a problem in that the polarization phase conversion efficiency of the optical article is affected by the non-uniform thickness of the quartz phase plate that requires a highly accurate thickness.

  The objective of this invention is providing the manufacturing method of an optical article which can process the optical article excellent in the polarization conversion efficiency with high precision, and the optical article.

[Application Example 1]
A method for manufacturing an optical article according to this application example is a method for manufacturing an optical article including a translucent member and an inorganic crystal material, and includes one surface of the first translucent member and the inorganic material. A pre-polishing adhesion step of adhering one surface of the crystalline material with a first adhesive layer made of an adhesive, and the other surface of the first translucent member using the other surface of the inorganic crystalline material as a reference surface And a second polishing step for polishing the inorganic crystalline material to a predetermined thickness using the other surface of the first light-transmissive member as a reference surface. It is characterized by that.
In this application example having this configuration, in the method of manufacturing an optical article including the translucent member and the inorganic crystal material layer, first, on the bonding surface of the first translucent member to which the inorganic crystal material is bonded. By polishing the other surface that is not present, the other surface of the first translucent member is formed in parallel with the other surface of the inorganic crystal material. Thereafter, the inorganic crystal material layer is polished in a state where the other surface of the formed first translucent member is supported as a reference surface. By this method, the in-plane thickness of the inorganic crystal material can be made uniform, so that the polarization conversion efficiency is excellent and an optical article including the inorganic crystal material can be processed with high accuracy.

[Application Example 2]
The method for manufacturing an optical article according to this application example includes the first translucent member, the first adhesive layer, a laminate made of the inorganic crystal material, a second adhesive layer made of an adhesive, A lamination process of repeatedly laminating a polarization separation film, a second translucent member, a reflection film, and a third adhesive layer made of an adhesive in order is provided, and the laminate is expressed by the following formula (1) It is formed to a thickness that satisfies

[Formula 1]
t1 = t2-t3-t4 (1)
In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.

  In this application example of this configuration, the first translucent member, the first adhesive layer and the laminate made of the inorganic crystal material, the second adhesive layer, the polarization separation film, the second In the optical article in which the translucent member, the reflective film, and the third adhesive layer are repeatedly laminated in order, the thickness of the laminate, the thickness of the second translucent member, the thickness of the second adhesive layer, And since the thickness of the 3rd contact bonding layer was set as the structure which satisfy | fills said Formula (1), the light quantity loss by pitch shift | offset | difference can be suppressed and polarization light quantity can fully be ensured. That is, the optical quality can be improved.

[Application Example 3]
The method for manufacturing an optical article according to this application example includes a first layer made of the first translucent member, the first adhesive layer and the inorganic crystal material, a polarizing separation film, and a second adhesive. A layering step in which the adhesive layer, the second translucent member, the reflective film, and the third adhesive layer made of an adhesive are sequentially laminated, and the laminate is represented by the following formula (2): It is formed to a thickness that satisfies

[Formula 2]
t1 = t2 + t3-t4 (2)
In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.

  In this application example having this configuration, the first translucent member, the first adhesive layer and the laminate made of the inorganic crystal material, the polarization separation film, the second adhesive layer, and the second In an optical article in which a translucent member, a reflective film, and a third adhesive layer are repeatedly laminated in order, the thickness of the laminate, the thickness of the second translucent member, and the thickness of the second adhesive layer And since the thickness of the 3rd contact bonding layer was set as the structure which satisfy | fills said Formula (2), the light quantity loss by a pitch shift | offset | difference can be suppressed and polarized light quantity can fully be ensured. That is, the optical quality can be improved.

[Application Example 4]
The method for manufacturing an optical article according to this application example includes the first translucent member, the first adhesive layer, a laminate made of the inorganic crystal material, a second adhesive layer made of an adhesive, A layering step in which a polarization separation film, a second translucent member, a third adhesive layer made of an adhesive, and a reflective film are sequentially laminated, and the laminate is expressed by the following formula (3) It is formed to a thickness that satisfies

[Formula 3]
t1 = t2−t3 + t4 (3)
In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.

  In this application example of this configuration, the first translucent member, the first adhesive layer and the laminate made of the inorganic crystal material, the second adhesive layer, the polarization separation film, the second In an optical article in which a translucent member, a third adhesive layer, and a reflective film are repeatedly laminated in order, the thickness of the laminate, the thickness of the second translucent member, and the thickness of the second adhesive layer And since the thickness of the 3rd contact bonding layer was set as the structure which satisfy | fills said Formula (3), the light quantity loss by a pitch shift | offset | difference can be suppressed and sufficient polarized light quantity can be ensured. That is, the optical quality can be improved.

[Application Example 5]
In the method of manufacturing an optical article according to this application example, the inorganic crystal material is a crystal, and the optical article is a polarized beam formed by laminating the translucent member, the crystal, a polarization separation film, and a reflection film. It is a splitter.
In this application example of this configuration, a polarizing beam splitter (with excellent polarization conversion efficiency) that can be processed with high accuracy by manufacturing using an inorganic crystal material made of quartz in the above-described steps. Polarized Beam Splitter, PBS) can be manufactured.

[Application Example 6]
An optical article according to this application example is an optical article including a translucent member, an inorganic crystal material, and an adhesive layer that adheres the translucent member and the inorganic crystal material. The surface of the inorganic crystal material and the interface between the adhesive layer and the inorganic crystal material layer are practically parallel to each other.
In this application example having this configuration, the thickness of the inorganic crystal material layer becomes uniform, so that an optical article excellent in polarization conversion efficiency can be provided.

[Application Example 7]
In the optical article according to this application example, the inorganic crystal material is a crystal, and the optical article is a polarization beam splitter in which the translucent member, the crystal, a polarization separation film, and a reflection film are laminated. .
In this application example of this configuration, as described above, a polarization beam splitter (Polarized Beam Splitter, PBS) in which a polarization separation film and a reflection film are laminated on an inorganic crystal material layer made of quartz having a uniform thickness. The same effects as described above can be achieved.

Embodiments of the present invention will be described with reference to the drawings. Here, in each embodiment, the same components are assigned the same reference numerals, and the description thereof is omitted or simplified.
[First embodiment]
A first embodiment will be described with reference to FIGS. FIG. 1 is a view showing an end face of a polarization beam splitting conversion element according to the first embodiment, and FIGS. 2 and 3 are cross-sectional views showing main parts of FIG. Here, the polarization separation conversion element is a PS conversion element (or polarization beam splitter, Polarized Beam Splitter, PBS) as an optical article. This polarization separation / conversion element is used in, for example, a liquid crystal projector apparatus.
In FIG. 1, a polarization separation / conversion element 1 is a flat plate member in which a first light transmissive member 11 and a second light transmissive member 12 are alternately arranged with a polarization separation / conversion unit 13 interposed therebetween. . Each of the first light transmissive member 11 and the second light transmissive member 12 is provided with a reflecting portion 14. The reflection unit 14 is disposed at an intermediate position between the adjacent polarization separation conversion units 13.
The first light transmissive member 11 and the second light transmissive member 12 have their light incident side plane and light emission side plane parallel to each other, and polarization separation is performed at an angle of 45 ° with respect to these planes. The conversion unit 13 and the reflection unit 14 are arranged in parallel to each other. In the present embodiment, the polarization separation / conversion element 1 has a left-right symmetric structure, but may have an asymmetric structure arranged in parallel in only one direction.

The 1st translucent member 11 and the 2nd translucent member 12 are shape | molded from glass including optical glass, such as BK7, white plate glass, borosilicate glass, and blue plate glass.
As shown in FIG. 2, the polarization separation conversion unit 13 includes a first adhesive layer 131, a retardation plate 132, a second adhesive layer 133, and a polarization separation film 134.
The first adhesive layer 131 and the second adhesive layer 133 are layers made of an adhesive, and a general photocurable adhesive can be used as the adhesive.
The phase difference plate 132 is a strip-shaped half-wave plate, and an inorganic crystal material can be used. Examples of the inorganic crystal material include quartz made of a single crystal of SiO ₂ , and this quartz may be artificial quartz or natural quartz.
The polarization separation film 134 separates the incident light bundle (S-polarized light and P-polarized light) into an S-polarized partial light beam (S-polarized light) and a P-polarized partial light beam (P-polarized light). It is a film having the property of selectively transmitting one of them and selectively reflecting the other. For example, as shown in FIG. 3, S-polarized light is reflected and P-polarized light is transmitted. The polarization separation film 134 is configured by stacking layers of different materials, for example, a silicon oxide (SiO ₂ ) layer, a lanthanum aluminate layer, and a magnesium fluoride (MgF ₂ ) layer. These layers are composed of a plurality of layers, and are not illustrated in the present embodiment, but are composed of, for example, five layers. As it goes from the first translucent member 11 side to the second translucent member 12 side, a first layer, a second layer, a third layer, a fourth layer, and a fifth layer are formed. It is directly provided on the member 11. Among these layers, the first layer and the fifth layer are layers of silicon oxide (SiO ₂ ), the third layer is a layer of magnesium fluoride (MgF 2), and the second layer and the fourth layer are lanthanum aluminum. Nate layer.

The reflection unit 14 includes a reflection film 141 and a third adhesive layer 142.
The reflective film 141 is formed by laminating dielectric multilayer films. Of course, the dielectric multilayer film constituting the reflective film 141 has a composition and configuration different from those constituting the polarization separation film 134. The reflection film 141 is composed of a dielectric multilayer film that selectively reflects only the linearly polarized light component (S-polarized light or P-polarized light) reflected by the polarization separation film 134 and does not reflect other linearly polarized light components. Those are preferred.
The reflective film 141 may be formed by evaporating aluminum. When the reflective film 141 is formed of a dielectric multilayer film, a specific linearly polarized light component (for example, S-polarized light) can be reflected with a reflectance of about 98%. On the other hand, the reflectivity of the aluminum film is at most about 92%. Therefore, if the reflective film 141 is formed of a dielectric multilayer film, the amount of light emitted from the polarizing beam splitter array can be increased. Furthermore, the dielectric multilayer film has an advantage that it generates less heat because it absorbs less light than the aluminum film. In order to improve the reflectance of a specific linearly polarized light component, each of the films constituting the dielectric multilayer film (usually a structure in which two kinds of films are alternately laminated) constituting the reflective film 141 is used. The thickness or film material may be optimized.
As the third adhesive layer 142, the same material as that used in the first adhesive layer 131 and the second adhesive layer 133 can be used.

The thicknesses of these layers are defined as follows with reference to FIG.
The thickness of the first translucent member 11 is t11, the thickness of the first adhesive layer 131 is t12, the thickness of the retardation plate 132 is t13, the thickness of the second translucent member 12 is t2, and the second adhesive The thickness of the layer 133 is t3, and the thickness of the third adhesive layer 142 is t4.
Here, in order to ensure the light quantity of the emitted light with respect to the incident light incident on the polarization separation conversion element 1, from the intermediate position of the polarization separation film 134 to the intermediate position of the reflection film 141 including the first translucent member 11. And the pitch L2 from the intermediate position of the polarization separating film 134 to the intermediate position of the reflective film 141 including the second light transmissive member 12 are preferably the same (L1 = L2). That is, t2 = t11 + t12 + t13 + t3 + t4, and the thickness t1 of the laminate composed of the first translucent member 11, the first adhesive layer 131, and the retardation plate 132 is defined by the following equation. Note that the thicknesses of the polarization separation film 134 and the reflection film 141 are negligibly small compared to the thicknesses of the other layers.

[Formula 4]
t1 = t2-t3-t4 (1)

Next, a method for manufacturing an optical article according to the first embodiment will be described with reference to FIGS. FIG. 4 is a schematic diagram for explaining the lamination process in the first embodiment, FIG. 5 is a schematic diagram for explaining the polishing process in the first embodiment, and FIG. 6 is a schematic diagram for explaining the cutting process in the first embodiment. 7 is a schematic diagram illustrating a cutting process in the first embodiment.
First, a strip-shaped optical block 11A for forming the first light-transmissive member 11 and a strip-shaped optical block 12A for forming the second light-transmissive member 12 are prepared. The material of these strip-shaped optical blocks 11A and 12A is the same as that of the first translucent member 11 and the second translucent member 12.

[1. Adhesion process before polishing]
As shown in FIG. 4A, an adhesive is applied to one surface of the strip-shaped optical block 11A to form a first adhesive layer 131, and the strip-shaped retardation plate is formed by the first adhesive layer 131. 132A is adhered. In this way, a laminate including the strip-shaped optical block 11A, the first adhesive layer 131, and the strip-shaped retardation plate 132A is referred to as a laminate 20.

[2. Polishing process]
As shown in FIG. 5A, the polishing apparatus has a flat support plate 91 and a polishing surface 92A parallel to the support surface 91A of the support plate 91. The support surface 91A is polished. An apparatus having a grindstone 92 operable to draw a circle with the surface 92A held in parallel is used.
[2-1. First polishing step]
As shown in FIG. 5A, the plurality of stacked bodies 20 are supported on the support plate 91 so that the strip-like phase difference plate 132A is in contact with the support surface 91A. In each laminate 20, the thickness of the strip-shaped optical block 11A and the first adhesive layer 131 is not the same, and the thickness of the strip-shaped optical block 11A and the first adhesive layer 131 is not the same in one laminate 20 as well. It is uniform.
In the first polishing step, for example, the strip-shaped optical block 11A is polished to the position of the line l shown in FIG. 5A so that the laminate 20 having such a variation in thickness has a predetermined thickness. Thus, the total thickness of the stacked body 20 is made uniform. Thereby, the reference surface 20A is formed at the position of the line l. The reference surface 20A is formed on a surface that is practically parallel to the surface of the strip-shaped phase plate 132A.

[2-2. Second polishing step]
Next, as shown in FIG. 5B, the laminate 20 is inverted and supported on the support plate 91 so that the reference surface 20A is in contact with the support surface 91A. In the first polishing step, the total thickness of the laminate 20 is uniform, and the surface of the strip phase plate 132A and the support surface 91A are supported in parallel, so the strip phase plate 132A is uniformly polished. Then, the strip-like retardation plate 132A is polished to form the laminate 20 having a thickness t1.

[3. Reflection film and polarization separation film formation process]
As shown in FIG. 4B, a polarization separation film 134A for forming a polarization separation film 134 is formed on one surface of the strip-shaped optical block 12A, and a reflection film 141 is formed on the surface opposite to the one surface. A reflective film 141A for forming the film is formed. The polarization separation film 134A and the reflection film 141A are formed using a conventional method such as vacuum deposition, ion-assisted deposition, ion plating, or sputtering. The laminate obtained in this manner is referred to as a laminate 30.

[4. Bonding process]
As shown in FIG. 4C, the strip-shaped optical block 11A of the laminate 20 and the reflective film 141 of the laminate 30 are bonded together with an adhesive and integrated. The layer made of the adhesive applied here becomes the third adhesive layer 142. The laminate obtained in this way is referred to as laminate 40.
Then, a plurality of stacked bodies 40 are stacked through the second adhesive layer 133 made of an adhesive, and a stacked body 50 as shown in FIG. 6A is created.

[5. Cutting process]
In the cutting step, the stacked body 50 is cut into a predetermined shape.
As shown in FIG. 6A, a laminate 50 is prepared in a state where both ends are aligned.
Then, as shown in FIG. 6B, the stacked strip-like optical blocks 11A and 12A are cut at predetermined intervals along a direction L of 45 ° with respect to the plane. One cut block 11C is shown in FIG. As shown in FIG. 7A, the end face of the block 11C is a parallelogram. The block 11C has a structure in which the polarization separation conversion unit 13 and the reflection unit 14 are arranged at predetermined intervals. Thereafter, the predetermined position of the block 11C is cut along a direction V1 perpendicular to the plane.
[6. Joining process]
As shown in FIG. 7B, the polarized blocks 11C are formed by joining the cut blocks 11C side by side.

Therefore, in the first embodiment, the following operational effects can be achieved.
(1) A strip-shaped optical block 11A is prepared, and a strip-shaped retardation plate 132A is bonded to one surface of the strip-shaped optical block 11A via a first adhesive layer 131 made of an adhesive, whereby the laminate 20 is bonded. Form. Further, the strip-shaped optical block 11A is polished by supporting it on the support plate 91 so that the strip-like retardation plate 132A of the laminate 20 is in contact with the support surface 91A, thereby making the total thickness of the laminate 20 uniform. Then, the laminate 20 was inverted so that the reference surface 20A was in contact with the support surface 91A, and the strip-like retardation plate 132A was polished. Therefore, even if the thickness of the strip-shaped optical block 11A or the first adhesive layer 131 is not uniform, the strip-shaped optical block 11A is first polished to make the total thickness of the laminate 20 uniform. In the second polishing step, the thickness of the strip-like retardation plate 132A can be uniformly polished. That is, the surface of the strip-like retardation plate 132A and the interface between the strip-like retardation plate 132A and the first adhesive layer 131 are kept in a parallel state. Therefore, it is possible to manufacture a highly accurate polarization separation / conversion element 1 that does not affect the polarization conversion efficiency.

(2) As described above, even if the strip-shaped optical block 11A and the first adhesive layer 131 are non-uniform in thickness, the polarization separation conversion element 1 having a uniform total thickness and high accuracy can be manufactured. The thickness accuracy of the strip-shaped optical block 11A and the accuracy when applying the first adhesive layer 131 are not required. Therefore, since the manufacturing process is facilitated, the inexpensive polarization separation conversion element 1 can be efficiently manufactured.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In 2nd Embodiment, the structure and manufacturing method of the polarization separation conversion part of a polarization separation conversion element differ from 1st Embodiment.
FIG. 8 is an enlarged cross-sectional view showing a main part of a polarization separation / conversion element that is an optical article according to the second embodiment of the present invention, and FIG. 9 is a schematic view for explaining a lamination process in the second embodiment.
In FIG. 8, the polarization separation conversion unit 15 includes a first adhesive layer 151, a retardation plate 152, a polarization separation film 153, and a second adhesive layer 154.
The polarization separation film 153 has the same configuration as the polarization separation film 134 of the first embodiment, and the retardation plate 152 has the same configuration as the retardation plate 132 of the first embodiment. The adhesive used for the first adhesive layer 151 and the second adhesive layer 154 can also be the same as that used in the first embodiment.

The thicknesses of these layers are defined as follows with reference to FIG.
The thickness of the first translucent member 11 is t11, the thickness of the first adhesive layer 151 is t12, the thickness of the retardation film 152 is t13, the thickness of the second translucent member 12 is t2, and the second adhesion is performed. The thickness of the layer 154 is t3, and the thickness of the third adhesive layer 142 is t4.
Here, in order to secure the light quantity of the emitted light with respect to the incident light incident on the polarization separation conversion element 6, from the intermediate position of the polarization separation film 153 to the intermediate position of the reflection film 141 including the first light-transmissive member 11. And the pitch L2 from the intermediate position of the polarization separation film 153 to the intermediate position of the reflective film 141 including the second light-transmissive member 12 are preferably the same (L1 = L2). That is, t11 + t12 + t13 + t4 = t2 + t3, and the thickness t1 of the laminate including the first light transmissive member 11, the first adhesive layer 151, and the retardation plate 152 is defined by the following equation. Note that the thicknesses of the polarization separation film 153 and the reflection film 141 are negligibly small compared to the thicknesses of the other layers.

[Formula 5]
t1 = t2 + t3-t4 (2)

A method for manufacturing the polarization separation conversion element 6 having such a configuration will be described with reference to FIGS.
[1. Adhesion process before polishing]
First, a strip-shaped optical block 11A for forming the first translucent member 11 is prepared, and an adhesive is applied to one surface of the strip-shaped optical block 11A as shown in FIG. 9A. A first adhesive layer 151 is formed, and a strip-like phase difference plate 152A for forming the phase difference plate 152 is laminated on the first adhesive layer 151 and bonded. In this way, a laminate including the strip-shaped optical block 11A, the first adhesive layer 151, and the strip-shaped retardation plate 152A is referred to as a laminate 61.

[2. Polishing process]
In the polishing step, both surfaces of the laminate 61 are polished and processed into a predetermined thickness, that is, a thickness of t1 represented by the above-described formula (2). As a polishing method, the apparatus used in the first embodiment is used, and the first polishing process and the second polishing process are performed by the same method.
[3. Polarization separation film forming process]
Next, the polarization separation film 153A for forming the polarization separation film 153 on the strip-like retardation plate 152A of the laminate 61 having a predetermined thickness is vacuum-deposited, ion-assisted deposition, ion plating method, sputtering method. The conventional method such as the above is used. The laminated body obtained in this manner is referred to as a laminated body 63.

[4. Reflective film forming process]
As shown in FIG. 9B, a reflective film 141A for forming the reflective film 141 on one surface of the strip-shaped optical block 12A is formed by a conventional method such as vacuum deposition, ion-assisted deposition, ion plating method, sputtering method or the like. Form using method. The laminate obtained in this way is referred to as laminate 64.

[5. Bonding process]
As shown in FIG. 9C, the strip-shaped optical block 11A of the laminated body 63 and the reflective film 141A of the laminated body 64 are bonded together with an adhesive and integrated. The adhesive applied here becomes the third adhesive layer 142. The laminate obtained in this manner is referred to as a laminate 65.
Then, a plurality of stacked bodies 65 are stacked through an adhesive layer that becomes the second adhesive layer 154.

Thereafter, similarly to the first embodiment, the cutting step and the joining step are performed, and the polarization separation conversion element 6 shown in FIG. 8 is formed.
Therefore, in the second embodiment, the same effects as the effects (1) and (2) of the first embodiment can be achieved.

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, the configuration and the manufacturing method of the reflection part of the polarization separation conversion element are different from those in the first embodiment.
FIG. 10 is an enlarged cross-sectional view showing a main part of a polarization separation / conversion element that is an optical article according to a third embodiment of the present invention, and FIG. 11 is a schematic view for explaining a lamination process in the third embodiment.
In FIG. 10, the reflective portion 16 is formed by laminating a reflective film 161 and a third adhesive layer 162 in order from the first translucent member 11 side. The reflective film 161 has the same configuration as that of the reflective film 141 of the first embodiment, and the same adhesive as that used in the first embodiment can be used for the third adhesive layer 162. .

The thicknesses of these layers are defined as follows with reference to FIG.
The thickness of the first translucent member 11 is t11, the thickness of the first adhesive layer 131 is t12, the thickness of the retardation plate 132 is t13, the thickness of the second translucent member 12 is t2, and the second adhesive The thickness of the layer 133 is t3, and the thickness of the third adhesive layer 162 is t4.
Here, in order to secure the amount of the emitted light with respect to the incident light incident on the polarization separation conversion element 7, from the intermediate position of the polarization separation film 134 to the intermediate position of the reflection film 161 including the first light transmissive member 11. And the pitch L2 from the intermediate position of the polarization separating film 134 to the intermediate position of the reflective film 161 including the second light transmissive member 12 are preferably the same (L1 = L2). That is, t11 + t12 + t13 + t3 = t2 + t4, and the thickness t1 of the laminate including the first light transmissive member 11, the first adhesive layer 131, and the retardation plate 132 is defined by the following equation. Note that the thicknesses of the polarization separation film and the reflection film are negligibly small compared to the thicknesses of the other layers.

[Formula 6]
t1 = t2−t3 + t4 (3)

A method for manufacturing the polarization separation conversion element 7 having such a configuration will be described with reference to FIGS.
[1. Adhesion process before polishing]
First, a strip-shaped optical block 11A for forming the first translucent member 11 is prepared, and an adhesive is applied to one surface of the strip-shaped optical block 11A as shown in FIG. A first adhesive layer 131 is formed, and a strip-like retardation plate 132A for forming the retardation plate 132 is laminated on the first adhesive layer 131 and bonded. The laminate obtained in this way is referred to as laminate 71.

[2. Polishing process]
In the polishing step, both surfaces of the laminated body 71 are polished and processed into a predetermined thickness, that is, a thickness of t1 represented by the above formula (3). As a polishing method, the apparatus used in the first embodiment is used, and the first polishing process and the second polishing process are performed by the same method.

[3. Reflective film forming process]
Next, a reflective film 161A for forming the reflective film 161 on the other surface of the strip-shaped optical block 11A of the laminate 71 having a predetermined thickness is vacuum-deposited, ion-assisted deposition, ion plating method, sputtering method, etc. The conventional method is used. The laminate obtained in this way is designated as laminate 72.

[4. Polarization separation film forming process]
As shown in FIG. 11B, a polarization separation film 134A for forming the polarization separation film 134 on one surface of the strip-shaped optical block 12A is formed by vacuum deposition, ion assist deposition, ion plating method, sputtering method, or the like. Form using conventional methods. The laminate obtained in this way is referred to as laminate 73.

[5. Bonding process]
As shown in FIG. 11C, the reflective film 161A of the laminated body 72 and the strip-shaped optical block 12A of the laminated body 73 are bonded together with an adhesive and integrated. The adhesive applied here becomes the third adhesive layer 162. The laminate obtained in this manner is referred to as a laminate 74.
Then, a plurality of laminated bodies 74 are laminated through the second adhesive layer 133 made of an adhesive.

Thereafter, similarly to the first embodiment, the cutting step and the joining step are performed, and the polarization separation conversion element 7 shown in FIG. 10 is formed.
Therefore, in the third embodiment, the same effects as the effects (1) and (2) of the first embodiment can be achieved.

Hereinafter, examples will be described in order to confirm the effects of the present embodiment.
[Example 1]
Example 1 is an example of the polarization separation conversion element 1 corresponding to the first embodiment. The materials and thicknesses used for each layer are as follows.
First translucent member and second translucent member: glass (manufactured by SCHOTT (Germany), trade name “B270”), thickness of 2 to 3 mm
Phase difference plate: Artificial quartz, target center thickness 30μm
Adhesive layer: photocurable adhesive (trade name “UT20”, manufactured by Adel), thickness of several μm
Polarized light separation film: material described in the first embodiment, thickness of several μm
Reflective film: material described in the first embodiment, thickness of several μm

When a plurality of polarization separation / conversion elements having the above-described configuration were produced by the production method described in the first embodiment, the thickness of the retardation film after production was in the range of 28.5 μm to 31.5 μm. That is, the polishing error of the retardation plate was within ± 1.5 μm.
And about these polarization splitting conversion elements, the polarization conversion efficiency in each wavelength was measured using the Hitachi spectrophotometer U4100. The measurement results are shown in FIG.

[Comparative Example 1]
A plurality of polarization separation / conversion elements having the same configuration as in Example 1 were prepared by a conventional method. That is, the strip-shaped optical block 11A of the laminate 20 is supported on the support plate 91 so that the strip-shaped optical block 11A is in contact with the support surface 91A, and the strip-shaped retardation plate 132A is polished. The strip-shaped optical block 11A was polished by being supported on the support plate 91 so that the retardation plate 132A was in contact with the support surface 91A, thereby forming the laminate 20 having a thickness t1.

The thickness of the retardation plate after production was in the range of 27.0 μm or more and 33.0 μm or less. That is, the polishing error of the retardation plate was within ± 3.0 μm.
And about these polarization splitting conversion elements, the polarization conversion efficiency in each wavelength was measured using the Hitachi spectrophotometer U4100. The measurement results are shown in FIG.

In Example 1, the variation in the thickness of the crystal was in-plane ± 1.5 μm, and the variation was smaller than that in Comparative Example 1 of ± 3.0 μm.
Further, as can be seen from FIGS. 12 and 13, the polarization conversion efficiency is stably high in the wavelength region of 500 nm to 600 nm.

  The present invention can be used for optical articles used in liquid crystal projectors and other devices.

1 is an end view showing a polarization separation / conversion element that is an optical article according to a first embodiment of the present invention. The principal part expanded sectional view of FIG. The principal part expanded sectional view of FIG. Schematic explaining the lamination | stacking process in 1st Embodiment. Schematic explaining the grinding | polishing process in 1st Embodiment. Schematic explaining the cutting process in 1st Embodiment. Schematic explaining the cutting process in 1st Embodiment. The principal part expanded sectional view which shows the polarization separation conversion element which is an optical article of 2nd Embodiment of this invention. Schematic explaining the lamination | stacking process in 2nd Embodiment. The principal part expanded sectional view which shows the polarization separation conversion element which is an optical article of 3rd Embodiment of this invention. Schematic explaining the lamination | stacking process in 3rd Embodiment. 3 is a graph showing the results of Example 1. The graph which shows the result of the comparative example 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Polarization separation conversion element (optical article), 11 ... 1st translucent member, 12 ... 2nd translucent member, 13 ... Polarization separation conversion part, 14 ... Reflection part, 131 ... 1st contact bonding layer , 132 ... retardation plate, 133 ... second adhesive layer, 134 ... polarization separation film, 141 ... reflective film, 142 ... third adhesive layer

Claims (5)

A method for producing an optical article comprising a translucent member and an inorganic crystal material,
A pre-polishing adhesion step of adhering one surface of the first translucent member made of glass and one surface of the inorganic crystal material with a first adhesive layer made of an adhesive;
A first polishing step of polishing the other surface of the first light-transmissive member using the other surface of the inorganic crystal material as a reference surface;
And a second polishing step of polishing the inorganic crystal material to a predetermined thickness using the other surface of the first light-transmissive member polished in the first polishing step as a reference surface. A method for producing an optical article. In the manufacturing method of the optical article according to claim 1,
The first translucent member, the first adhesive layer and the laminate made of the inorganic crystal material, the second adhesive layer made of an adhesive, the polarization separation film, and the second translucent member And a laminating step of repeatedly laminating a reflective film and a third adhesive layer made of an adhesive in order,
The manufacturing method of the optical article characterized by forming the said laminated body in the thickness which satisfy | fills the following formula | equation (1).
t1 = t2-t3-t4 (1)
(In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.) In the manufacturing method of the optical article according to claim 1,
The first translucent member, the first adhesive layer and a laminate composed of the inorganic crystal material, a polarization separation film, a second adhesive layer composed of an adhesive, and a second translucent member And a laminating step of repeatedly laminating a reflective film and a third adhesive layer made of an adhesive in order,
The manufacturing method of the optical article characterized by forming the said laminated body in the thickness which satisfy | fills the following formula | equation (2).
t1 = t2 + t3-t4 (2)
(In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.) In the manufacturing method of the optical article according to claim 1,
The first translucent member, the first adhesive layer and the laminate made of the inorganic crystal material, the second adhesive layer made of an adhesive, the polarization separation film, and the second translucent member And a laminating step of repeatedly laminating a third adhesive layer made of an adhesive and a reflective film in order,
The manufacturing method of the optical article characterized by forming the said laminated body in the thickness which satisfy | fills the following formula | equation (3).
t1 = t2−t3 + t4 (3)
(In the formula, t1 is the thickness of the laminate, t2 is the thickness of the second translucent member, t3 is the thickness of the second adhesive layer, and t4 is the thickness of the third adhesive layer.) In the manufacturing method of the optical article in any one of Claims 1-4,
The inorganic crystalline material is quartz;
The method for manufacturing an optical article, wherein the optical article is a polarizing beam splitter formed by laminating the light-transmissive member, the crystal, a polarization separation film, and a reflection film.

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