JP2008209484A - Method for producing polarizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polarizer in which an effective region can be formed over the whole of the surface of a substrate, and, the desired number of polarizers can be inexpensively obtained with dimensions corresponding to a request and at an angle to the direction of ruggedness compared with the conventional production method for photonic crystals. <P>SOLUTION: The method for producing a polarizer comprises: a process where a prescribed sol liquid is applied over the whole of the surface of the first base material composed of a translucent inorganic material, so as to form a prescribed coating film; a process where, in a state where a master mold is pressed against the coating film of the first base material, heating-holding is performed, and the coating film is cured, so as to form a surface to which periodical rugged shape in a specified direction is imparted on the coating film; and a process where many units of double layer films where one unit is composed of the first layer of a high refractive index translucent material and the second layer of a low refractive index translucent material are stacked, so as to form a multilayer structure, and a polarizer original plate with a large area of ≥400 mm<SP>2</SP>where the whole face is made into an effective region is obtained, so as to provide a hybrid polarizer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polarizer which is a multilayer structure having a function of transmitting only a linearly polarized component in a specific direction of incident light, which is used in, for example, an optical apparatus using polarized light such as a liquid crystal projector and a liquid crystal display device. Is.

  A polarizer is an optical element for extracting linearly polarized light in a specific direction from light including a plurality of polarized light, and various configurations and forms are widely used. In particular, in the field of liquid crystal display technology, technological innovations such as miniaturization, weight reduction, and high brightness have advanced, and liquid crystal display devices using polarizers for various applications are rapidly spreading.

  Among them, in recent years, photonic crystals have attracted attention as ultra-compact optical circuits or as materials for realizing high-performance light-emitting devices such as laser and sensor substrate materials. A photonic crystal is a nanostructure having a periodic refractive index distribution by forming a fine concavo-convex structure on a substrate surface and periodically arranging a high refractive index material and a low refractive index material thereon. It is a device. By the periodic structure, an artificial defect called a photonic band gap can be formed, and the light propagation characteristics can be controlled by changing the hole diameter and the periodicity of the arrangement of the materials. This polarizer is expected to have many applications in fields such as optical communication and optical information processing.

  As a method of forming the periodic uneven structure on the substrate surface, for example, as shown in Patent Document 1, there is a method of forming a recess in the substrate by etching. In a glass or silicon substrate, a mask having a periodic pattern is formed on the surface by a photolithography technique, and a recess is formed by vapor phase etching such as ion beam etching through the mask.

  However, in the method of Patent Document 1, since the periodic structure portion is formed only by forming a thin film, it is a one-piece product that requires photolithography and etching for substrate processing. In addition, there is a problem that time is increased.

  As a method for solving the above problem, for example, as described in Patent Document 2, a predetermined sol solution is applied to the substrate surface, and a prototype having an uneven shape is pressed against the gel film in which the sol solution has changed. There is a method for producing a polarizer that forms a substrate having a concavo-convex structure by heating and curing a gel film.

Although the method of Patent Document 2 is an effective means in that it can mass-produce a polarizer having the same surface uneven shape, the size of the polarizer and the periodic uneven shape required by the client due to product model change, etc. When a design change such as the direction of the above occurs, the prototype must be newly produced, and improvement in the responsiveness to the changing needs every day is necessary. In addition, the method of Patent Document 2 requires the formation of a fine concavo-convex structure on the surface for each of the substrates. In addition, forming the concavo-convex on the entire surface of the substrate presses the prototype. Since this method is difficult, there will be an ineffective region where the surface irregularities are not formed at the edge of the substrate, and the presence of such an ineffective region may result in a desired polarizer being misaligned. It caused the problem that the function was not obtained.
JP 2001-228332 A JP 2005-181979 A

  An object of the present invention is to form an effective region on the entire surface of a substrate, and to obtain a desired number of polarizers at a low cost with an angle with respect to dimensions and uneven directions according to requirements, compared to a conventional photonic crystal manufacturing method. Another object of the present invention is to provide a method of manufacturing a polarizer that can be used.

In order to achieve the above object, the gist of the present invention is as follows.
(1) A step of applying a predetermined sol solution over the entire surface of the first base material made of a translucent inorganic material to form a predetermined coating film, and a state in which the prototype is pressed against the coating film of the first base material Heating and holding to cure the coating film to form a surface having a periodic concavo-convex shape in a specific direction on the coating film, and a high refractive index translucent material on the coating film. the first layer and the multilayer film of one unit of a second layer of low refractive translucent material, to form a multilayer structure with multiple units stacked polarizers original plate 400 mm ² or more large area entirely becomes effective area A process for obtaining a polarizer.

(2) The polarizer according to (1), further comprising: a step of cutting out a desired number of polarizers from the polarizer original plate at a required size and an angle with respect to the specific direction. Production method.

(3) The coating film is a sol solution mainly composed of at least one compound represented by Si (OC ₂ H ₅ ) ₄ , Si (OCH ₃ ) ₄ and SiCl ₄ , an aqueous acid solution and polyethylene glycol. The method for producing a polarizer according to the above (1) or (2), wherein the polarizer is formed by using the method.

(4) The coating film is mainly composed of at least one compound represented by RSi (OC ₂ H ₅ ) ₃ , RSi (OCH ₃ ) ₃ and RSiCl ₃ (R is a functional group) and an aqueous acid solution. The method for producing a polarizer according to the above (1) or (2), which is formed using a sol solution.

According to this invention, a predetermined sol solution is applied over the entire surface of the first base material made of a light-transmitting inorganic material to form a predetermined coating film, and a prototype is pushed onto the coating film of the first base material. Heating and holding in the applied state to cure the coating film, forming a surface with a periodic uneven shape in a specific direction on the coating film, and a high refractive index translucent light on the coating film A multi-layer structure is formed by laminating a multi-layered structure of one unit consisting of a first layer of material and a second layer of low refractive translucent material to form a multi-layered structure, with a large area of 400 mm ² or more where the entire surface becomes an effective area. And a step of obtaining a polarizer original plate, so that various polarizers can be freely cut out from the polarizer original plate. Therefore, compared with a conventional photonic crystal manufacturing method, It becomes possible to obtain a desired number of polarizers at an angle with respect to the direction of the unevenness, In addition, since the polarizer can be cut out from the polarizer original plate so as not to include the ineffective area existing at the edge of the substrate, a method for manufacturing a polarizer in which the effective area is formed on the entire surface of the substrate is provided. It became possible to do.

  Next, a method for manufacturing a polarizer according to the present invention will be described with reference to the drawings.

  The manufacturing method of the present invention is a so-called photonic crystal type polarizer manufacturing method. The photonic crystal type polarizer includes a first layer of a high refractive index light-transmitting material and a second layer of a low refractive index light-transmitting material on a substrate having periodic irregularities in at least one direction of the surface. This is a polarizer formed by laminating a plurality of unit multilayer films to form a first multilayer structure.

In the conventional photonic crystal manufacturing method, the manufacturing cost of the polarizer increases because the conventional photonic crystal manufacturing method is a one-piece product that requires advanced technology such as lithography technology and etching technology to manufacture the substrate. In addition, the manufacturing method of manufacturing a substrate using sol-gel technology can manufacture a large number of polarizers of the same shape, but it can cope with changes in the size of the polarizer and the direction of unevenness due to model changes, etc. In addition, since it is difficult to form irregularities on the entire surface of the substrate, it is difficult to form irregularities on the entire surface of the substrate. We have earnestly researched a method for manufacturing a polarizer in which a desired number of polarizers can be obtained at an inexpensive angle with respect to the direction of the projections and depressions, and the entire surface is an effective region.
As a result, a predetermined sol solution is applied over the entire surface of the first base material made of a light-transmitting inorganic material to form a predetermined coating film, and the prototype is pressed against the coating film on the first base material. Heating and holding to cure the coating film to form a surface having a periodic concavo-convex shape in a specific direction on the coating film, and a high refractive index translucent material on the coating film. the first layer and the multilayer film of one unit of a second layer of low refractive translucent material, to form a multilayer structure with multiple units stacked polarizers original plate 400 mm ² or more large area entirely becomes effective area It is possible to cut out a desired number of polarizers having a size and an angle with respect to the concave / convex direction according to the demand, and do not include an ineffective region existing at the edge of the substrate from a large-area polarizer original plate The polarizer can be cut out, and the substrate is made by the sol-gel method It has been found that a polarizer can be produced at low cost by using.

FIG. 1 is a flowchart for explaining the steps of a method for producing a polarizer according to the present invention.
As shown in FIG. 1, the specific manufacturing method of the present invention is to apply a predetermined sol solution to a first base material 11 (FIG. 1 (a)) made of a translucent inorganic material, and to form a predetermined coating film 12. (FIG. 1B) and the state in which the prototype 13 is pressed (FIG. 1C), the coating film 14 is cured by heating and holding at about 40 to 200 ° C. in a specific direction. A step of forming a surface 15 provided with a periodic concavo-convex shape (FIG. 1D), a first layer 16 of a high refractive index light transmitting material and a first layer of a low refractive light transmitting material on the coating film 14. A multi-layer structure 19 is formed by laminating a single unit of the multilayer film 18 composed of two layers 17 to form a multilayer structure 19, and a large-area polarizer original plate 20 of 400 mm ² or more whose entire surface is an effective area is formed (FIG. 1). (e)) a polarizer comprising a step.

The substrate 11 of the inorganic polarizer is preferably made of a crystalline material, an amorphous material, or a crystallized glass material. Examples of the crystalline material include silicon, examples of the amorphous material include quartz glass, soda lime glass, and borosilicate glass. Examples of the crystallized glass material include β- Examples thereof include crystallized glass materials containing a quartz solid solution crystal or a β-eucryptite solid solution as a main component.

Further, the coating film uses a sol liquid mainly composed of at least one compound represented by Si (OC ₂ H ₅ ) ₄ , Si (OCH ₃ ) ₄ and SiCl ₄ , an acid aqueous solution and polyethylene glycol. It is preferable to form them. Furthermore, it is preferable to contain 5 to 20% by mass of polyethylene glycol in the sol solution. If it is less than 5% by mass, the film hardness may be too high to be molded, and if it exceeds 20% by mass, the sol solution may be difficult to cure. The molecular weight of polyethylene glycol is preferably 400 to 2000. If the molecular weight is less than 400, the film hardness may be too high to be molded, and if it exceeds 2000, the sol solution may be difficult to cure. Moreover, it is preferable to contain alcohol in a sol liquid. It is preferable that the alcohol mainly contains a liquid selected from the group consisting of ethanol, methanol, and isopropyl alcohol because the alcohol remains excessively in the gel film at the time of molding so that bubble defects do not occur. The alcohol content in the sol solution is preferably 10 to 40 parts by mass. This is because when the amount is less than 10 parts by mass, uniform stirring of the sol solution becomes difficult, and when it exceeds 40 parts by mass, a sufficient coating thickness of the surface coating layer may not be obtained.

  In addition, as shown in FIG. 2, for example, the surface 15 provided with the concavo-convex shape may have a trapezoidal shape (FIG. 2 (a)) or a triangular shape (FIG. 2 (b)). Instead, it is determined by the shape of the prototype 13. In addition, the uneven | corrugated arrangement | positioning pitch W is the range of 175-300 nm normally. The prototype 13 is formed by applying a resist on a substrate made of quartz, borosilicate, silicon, or the like, patterning it using an electron beam drawing or lithography technique, and then transferring the surface shape using a dry etching technique or the like. Can be produced.

In the present invention, the surface 15 provided with a periodic uneven shape in a specific direction has an area of 400 mm ² or more. Periodic irregularities after coating the sol liquid 12, original 13 having a 400 mm ² or more large area, or a small angular deviation prototype 13 is less than 1 ° in the area of 25～300Mm ^2, the positional deviation 0.5 By taking care that the thickness is less than mm and pressing and holding one of the ones arranged so as to have an area of 400 mm ² or more, the uneven shape can be transferred and molded. The reason for paying attention to the angle shift and position shift is that if an angle shift of 1 ° or more occurs, a groove angle shift of 1 ° or more with respect to the outer shape occurs between the elements when the dicer is cut, and adjustment during mounting becomes difficult. This is because if a misalignment of 0.5 mm or more occurs, it may cause an angle misalignment when the angle of the dicer cutting stage is set, and there may be an ineffective area on the outer periphery of the cut product. is there. Also, if surface accuracy (flatness) is poor, transfer unevenness is likely to occur. Therefore, in order to achieve large area transfer, the surface accuracy during transfer is preferably within 10 μm, and the coating thickness of the sol solution If there is, the coating thickness distribution of the sol solution should be within 1 μm because the film thickness distribution after transfer is likely to occur.If the in-plane pressure distribution is large, transfer unevenness is likely to occur, so the in-plane pressure distribution is , Preferably within ± 10%. Further, when there is a temperature distribution, a curing failure is likely to occur, so that the temperature distribution during transfer is preferably ± 20%.

The high refractive index light-transmitting material used for the first layer 16 of the inorganic polarizer is, for example, Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₅ , HfO ₂ or a synthetic material thereof. Examples of the low refractive index translucent material used for the second layer 17 include SiO ₂ , MgF ₂ , and synthetic materials thereof. If the said material is used, sufficient heat resistance can be ensured and it is preferable at the point which can manufacture a polarizer with few optical losses at low cost.

  In addition, the multilayer film 18 is formed by using a commercially available film forming apparatus, alternately applying sputtering or etching of the high refractive material or low refractive material on the coating film, and forming periodic irregularities in a specific direction. Alternatively, the first layer 16 and the second layer 17 having a wave shape can be alternately stacked.

Furthermore, the method for manufacturing a polarizer according to the present invention may include a step (FIG. 1 (f)) of cutting out a desired number of polarizers from the polarizer original plate 20 with a dimension according to a request and an angle with respect to the specific direction. preferable. By making the area of the polarizer original plate 20 as large as 400 mm ² or more, it becomes possible to cut out the necessary number of polarizers 21 to 24 from the large-area polarizer original plate 20 as shown in FIG. It is also possible to cut out polarizers 25 having different concavo-convex directions and sizes. Furthermore, since all of the multilayer structure is an effective region as a polarizer, it is possible to prevent a dimensional defect caused by a cutting position shift at the time of cutting, which has occurred in a conventional manufacturing method.

  The polarizer is preferably cut out by using a dicing saw or a slicer from the viewpoint that an accurate cutting dimension can be obtained. Moreover, it is preferable that a protective film such as a resist is pasted on the surface when the polarizer is cut out from the viewpoint of preventing contamination of the surface. Furthermore, it is preferable to chamfer edges and corners so that the polarizer after cutting can be used as a product.

  In the present invention, a linearly polarized light generating device (not shown) including means (not shown) for generating specific color light and a polarizer manufactured by the manufacturing method of the present invention described above is manufactured. It is possible. For example, when the color light is blue, the means for generating the specific color light may be constituted by a mercury lamp and a specific filter. The linearly polarized light generating device is not particularly limited as long as it is a device that generates linearly polarized light, and examples thereof include a projector and a liquid crystal television.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

Next, a polarizer according to the present invention was prototyped and evaluated, which will be described below.
(Example)
In the example, first, a resist was coated on a glass substrate, and a concavo-convex pattern transfer with a period of 200 nm was performed by EB drawing, thereby producing a prototype having a size of 75 mm × 75 mm. After making the prototype, apply a sol-gel solution mainly composed of tetraethoxysilane, polyethylene glycol, ethanol, and acid aqueous solution on the first substrate made of glass, and press the prototype to transfer the uneven shape. A film was formed. Then, after firing the produced substrate at 300 ° C., using a film forming apparatus, a first layer made of Ta ₂ O ₅ which is a high refractive light transmitting material (refractive index 2.22) and a low refractive light transmitting material (refractive index). A polarizer original plate having a size of 75 mm × 75 mm was formed by alternately applying the second layer made of SiO _2, which is 1.48), by performing sputtering and ion etching. The obtained multilayer structure was attached to a glass plate with wax, and nine polarizers having a size of 20 mm × 24 mm were cut using a dicer in the direction along the X axis and the Y axis as shown in FIG. . Since FIG. 4 is a schematic diagram, the ineffective area of the polarizer is not described.

(Comparative example)
In the comparative example, by using the method of Patent Document 2, first, a resist was coated on a quartz substrate, and a concavo-convex pattern transfer with a period of 200 nm was performed by EB drawing, thereby producing a prototype having a size of 20 mm × 24 mm. After making the prototype, apply a sol-gel solution mainly composed of tetraethoxysilane, polyethylene glycol, ethanol, and acid aqueous solution on the first substrate made of glass, and press the prototype to transfer the uneven shape. A film was formed. After that, the fabricated substrate is baked at 350 ° C., and then a first layer made of Ta ₂ O ₅ which is a high refractive light transmissive material (refractive index 2.22) and a low refractive light transmissive material (refractive index) are formed using a film forming apparatus. A polarizer having a size of 20 mm × 24 mm was manufactured by alternately applying the second layer made of SiO _2, which is 1.48), by performing sputtering and ion etching.

  Various tests were performed on the polarizers produced in the above Examples and Comparative Examples. The evaluation method of the test conducted in this example is shown below.

(Evaluation methods)
(1) Mass productivity The mass productivity of the polarizers produced in Examples and Comparative Examples was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
○: Two or more polarizers can be produced from one multilayer structure.
X: Two or more polarizers cannot be produced from one multilayer structure.

(2) Polarizer effective area | region The polarizer effective area | region of the polarizer produced in the Example and the comparative example was measured. Specifically, the transmittance difference between the TM transmittance and the TE transmittance is measured while scanning the surface of the polarizer with the light beam diameter reduced to 1 mmφ in the spectrophotometer, and the TE transmittance and the TE transmittance are measured. The polarization characteristics were evaluated by converting the transmittance ratio to dB, and a portion where the polarization characteristics were 20 dB or more was regarded as an effective region, and a portion where the polarization properties were less than 20 dB was regarded as a non-effective region. In addition, about the Example, it was set as the average value about the effective area | region of nine obtained polarizers. The results are shown in Table 1.

  From the results shown in Table 1, it can be seen that the example has higher productivity than the comparative example, and is excellent in the effective region of the polarizer. In addition, since the produced polarizer original plate has an area of 75 mm x 75 mm, it can be cut out at an angle with respect to the dimension and the direction of the unevenness according to the request, and has a response to the request. I understand.

According to the present invention, a predetermined sol solution is applied over the entire surface of the first base material made of a translucent inorganic material to form a predetermined coating film, and a prototype is pressed onto the coating film of the first base material. Heating and holding in the applied state to cure the coating film, forming a surface with a periodic uneven shape in a specific direction on the coating film, and a high refractive index translucent light on the coating film A multi-layer structure is formed by laminating a multi-layered structure of one unit consisting of a first layer of material and a second layer of low refractive translucent material to form a multi-layered structure, with a large area of 400 mm ² or more where the entire surface becomes an effective area. The step of obtaining the polarizer original plate enables an effective area to be formed on the entire surface of the substrate, and compared with the conventional photonic crystal manufacturing method, the desired number of pieces can be formed at an angle with respect to the required dimensions and the direction of the irregularities. It is possible to provide a manufacturing method of a polarizer that can obtain a polarizer of a low cost became.

It is a flowchart for demonstrating the manufacturing process of the polarizer by this invention. It is a cross-sectional schematic diagram which shows embodiment of the board | substrate and original pattern by this invention. It is a figure which shows that a polarizer can be cut out with a various form from the large area polarizer manufactured with the method by this invention. In an Example, it is a figure which shows the cutting | disconnection location when cutting out a predetermined | prescribed polarizer from the large area | region polarizer original plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st base material 12 Sol liquid 13 Prototype 14 Gel layer 15 Coating film 16 1st layer 17 2nd layer 18 Multilayer film 19 Multilayer structure 20 Polarizer original plates 21-25 Polarizer W Arrangement pitch of unevenness

Claims (4)

Applying a predetermined sol solution over the entire surface of the first base material made of a translucent inorganic material, and forming a predetermined coating film;
Heating and holding in a state in which the prototype is pressed against the coating film of the first base material to cure the coating film, and forming a surface with a periodic uneven shape imparted to the coating film in a specific direction; ,
On the coating film, a multi-layered structure is formed by laminating a multi-layer of one unit consisting of a first layer of a high refractive index translucent material and a second layer of a low refractive translucent material to form a multilayer structure. 400m effective area
and a step of obtaining a polarizer original plate having a large area of m ² or more.   The method for producing a polarizer according to claim 1, further comprising a step of cutting out a desired number of polarizers from the polarizer original plate at a required size and an angle with respect to the specific direction. The coating film is formed using a sol liquid mainly composed of at least one compound represented by Si (OC ₂ H ₅ ) ₄ , Si (OCH ₃ ) ₄ and SiCl ₄ , an acid aqueous solution and polyethylene glycol. The method for producing a polarizer according to claim 1, wherein: The coating film comprises a sol solution mainly composed of at least one compound represented by RSi (OC ₂ H ₅ ) ₃ , RSi (OCH ₃ ) ₃ and RSiCl ₃ (R is a functional group) and an aqueous acid solution. The method for producing a polarizer according to claim 1, wherein the polarizer is formed by using.

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