WO2011122500A1 - Method for producing polarizing glass - Google Patents

Method for producing polarizing glass Download PDF

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Publication number
WO2011122500A1
WO2011122500A1 PCT/JP2011/057472 JP2011057472W WO2011122500A1 WO 2011122500 A1 WO2011122500 A1 WO 2011122500A1 JP 2011057472 W JP2011057472 W JP 2011057472W WO 2011122500 A1 WO2011122500 A1 WO 2011122500A1
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Prior art keywords
glass
stretching
manufacturing
polarizing glass
polarizing
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PCT/JP2011/057472
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French (fr)
Japanese (ja)
Inventor
拓朗 池田
浩三 前田
ひとみ 松本
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日本山村硝子株式会社
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Publication of WO2011122500A1 publication Critical patent/WO2011122500A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/02—Re-forming glass sheets
    • C03B23/037—Re-forming glass sheets by drawing
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B23/00—Re-forming shaped glass
    • C03B23/04—Re-forming tubes or rods
    • C03B23/047—Re-forming tubes or rods by drawing
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C14/00—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix
    • C03C14/004—Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix the non-glass component being in the form of particles or flakes
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2214/00—Nature of the non-vitreous component
    • C03C2214/04—Particles; Flakes

Definitions

  • the present invention relates to a method of manufacturing a polarizer used for an optical isolator, a liquid crystal display element or the like.
  • Patent Documents 1 and 2 disclose basic methods for producing a polarizer containing dispersed metallic silver particles having shape anisotropy.
  • shape-anisotropic silver halide grains are obtained by precipitating silver halide grains by heat treating glass containing Ag and halogen (Cl, Br or I) as components, and then extruding or stretching the glass. Then, the glass is dispersed and contained, and then is subjected to a reduction treatment to obtain a polarizing glass containing dispersed shape anisotropic metallic silver particles.
  • Patent Documents 3 and 4 show that the polarizing glass thus produced has a deviation in the angle of the polarization axis in the glass plate surface. However, Patent Documents 3 and 4 describe that the stretching stress and the temperature should be adjusted, but do not describe how to do it specifically.
  • Patent Document 5 in the stretching process, the temperature distribution of the heating furnace used for stretching is set so that the temperature becomes lower at both ends in the direction perpendicular to the stretching direction, so that the glass at the end in the width direction during stretching is set. A method for relatively increasing the cooling rate from the center is described.
  • Patent Document 6 describes a method of controlling the output of the heater in the stretching process so that the outer shape of the preform contracts at an inclination angle of 5 ° to 20 ° with respect to the longitudinal direction of the preform. Has been. In such a method, the heater device becomes long, the end portion of the preform cannot be effectively used, and the yield deteriorates.
  • Patent Document 7 in the stretching step, the stretching speed is maintained so that the angle formed by the side edges of the plate during stretching with respect to the stretching direction is less than 0.075 ° so that the width of the stretched glass becomes substantially constant. It describes that the film is stretched while being controlled. However, as specific means for that purpose, it is only described to synchronize the rotation of a pair of rollers for stretching and to change the rotation speed of the rollers according to the amount of the base glass.
  • Patent Document 8 describes a method of forcibly cooling only a central portion in the width direction by blowing a cooling gas from a nozzle on a glass sheet that is being stretched in a stretching process.
  • forced cooling has the problem of complicating the control of the device if heating and cooling are performed simultaneously.
  • the preform thickness is 3 mm or more
  • the movement speed of the preform is set to 15 mm / min or less
  • the take-up speed of the stretched glass sheet is set to 300 mm / min or less.
  • a production method characterized by heating and drawing is described. This method is a method of preventing the bending of the plate and does not reduce the in-plane distribution.
  • a glass composition containing Ag for manufacturing a polarizer for example, a glass containing, as a main component, SiO 2 , B 2 O 3 , Al 2 O 3 , alkali metal oxide (R 2 O), or the like is used. It is known to use a material to which halogen is added, for example, to use a glass in which metal halide particles are dispersed and contained (Patent Documents 1, 2, 10 to 14).
  • Patent Documents 3 to 9 are disclosed as methods for reducing the deviation of the angle of the polarization axis, but these require special temperature control or the like to be applied to the manufacturing process. Therefore, there is a problem that the process becomes complicated and the manufacturing cost is increased.
  • an object of the present invention is to provide a simpler method for reducing the deviation of the angle of the polarization axis in the obtained polarizing glass in the production of the polarizing glass.
  • the polarizing axis (absorption axis) of the stretched glass is in the stretching direction (that is, the direction in which the stretching load acts on the glass preform) as it is away from the center line as shown in FIG.
  • the present inventor confirmed that it shifted so as to spread obliquely outward.
  • the inventor further divides the stretching process into two or more stages as shown in FIG. 2, and stretches in the direction opposite to the stretching direction of the first stage in at least one of the plurality of stretching processes.
  • the deviation of the angle of the polarization axis can be eliminated or reduced.
  • the present invention has been completed by further studies based on this discovery.
  • Step (b) is repeated at least once, and in at least one of the repeated steps (b), the direction in which the glass is deformed is the first time in step (b) that the glass is deformed.
  • step (b) 2. 2. The production method according to 1 above, wherein the deformation of the glass in step (b) is performed by stretching. 3. 3. The production method according to 1 or 2 above, wherein step (b) is repeated once. 4). 4. In step (b), when the first draw ratio of the glass is n 1 and the second draw ratio is n 2 , n 1 / n 2 is 0.05 to 3.0. 4. Manufacturing method 5. The production method according to 4 above, wherein n 1 ⁇ n 2 is 5 or more. 6. The production method according to 4 or 5 above, wherein n 1 is 20 or less. 7). 7. The production method according to any one of 4 to 6 above, wherein the initial stretching stress in step (b) is 10 kgf / cm 2 or more. 8). 8.
  • the “polarization axis angle shift” means that the polarization at the portion of the polarizing glass increases as it moves away from the center line of the polarizing glass in the lateral direction (plus or minus direction) as shown in FIG. This means that the direction of the axis (absorption axis) is shifted obliquely with respect to the stretching direction.
  • FIG. 3 for the sake of convenience, the horizontal position from the center line of the polarizing glass is displayed with the right side of the drawing as plus and the left side as minus.
  • the magnitude [ ⁇ ] of the deviation of the angle of the polarization axis is indicated by the angle formed by the polarization axis with respect to the stretching direction. , Displays counterclockwise as positive and clockwise as negative.
  • the deviation of the angle of the polarization axis is a problem because there is a “variation” in the angle of the polarization axis depending on the position on the polarizing glass surface. Because. Therefore, the difference (absolute value) existing between the angles of the respective polarization axes at two distant points on the polarizing glass surface, or the polarization per unit length obtained by dividing this by the distance between the two points. The change in the angle of the axis is the actual object of evaluation.
  • various glass containing metal halide particles that can be reduced to metal particles can be used as the base glass.
  • a glass mainly composed of SiO 2 , B 2 O 3 , Al 2 O 3 , alkali metal oxide (R 2 O) or the like with Ag and halogen added can be used.
  • R 2 O alkali metal oxide
  • Patent Document 1 US Pat. No. 4,282,202
  • Patent Document 2 US Pat. No. 4,479,819
  • Patent Document 10 US Pat. No. 5,252,524
  • Patent Document 11 US Pat. No.
  • Patent Document 12 6,777,359 (Patent Document 12), US Pat. No. 7,468,148 (Patent Document 13), or US Pat. No. 7510989 (Patent Document 14), and used as the composition of the base glass in the present invention. However, it is not limited to them.
  • SiO 2 20 to 67% by weight
  • B 2 O 3 14 to 35% by weight
  • Al 2 O 3 0 to 25% by weight
  • P 2 O 5 0 to 25% by weight
  • Li 2 O + Na 2 O + K 2 O + Cs 2 O: 4 to 20% by weight can be suitably used as a base.
  • silver and halogen contained in these glasses include: Ag: 0.05 to 1.5% by weight, Cl + Br: more than the chemical equivalent of Ag, However, it is not limited to this range.
  • the applicant of the present application in an unpublished patent application (Japanese Patent Application No. 2009-136209), can use a glass having the following composition suitably for manufacturing a polarizer, and in particular, after stretching the glass, It has been confirmed that the reduction treatment can be performed in a short time in a hydrogen atmosphere of 1 atm.
  • R 1 represents Li, Na, K and Cs comprehensively, provided that Li 2 O: 0 to 5 wt%, Na 2 O: 0 to 9 wt%, K 2 O: 0 to 12 wt%, Cs 2 O: 0 to 6% by weight.
  • Cl 0.1 to 1.0% by weight
  • Br 0.01 to 0.5% by weight
  • F 0 to
  • the raw materials such as various oxides, halides, hydroxides, nitrates, sulfates and carbonates are prepared and melted using a known method so that the glass composition of the base material is in the above composition range.
  • the glass melt can be poured into a mold, molded, and heat treated to precipitate silver halide grains.
  • the step of deforming the glass is sufficient only two times, but the same effect can be obtained even if it is performed three times or more.
  • the last of the deformation steps has the greatest effect on the absorption maximum wavelength of the polarizing glass.
  • the stretching in the final stage is preferably performed at a temperature at which the glass has a viscosity of 10 6 to 10 9 Poise and a stress of 50 to 500 kgf / cm 2 .
  • the stretching is preferably performed so that the average aspect ratio (number average) of silver halide grains is at least 2: 1. There is no particular upper limit to the aspect ratio, and it can be set appropriately according to the purpose.
  • n 1 / n 2 is 0.05 to 3 when the stretching ratio in the first stretching is n 1 and the stretching ratio in the second stretching is n 2 .
  • 0 is preferable, 0.1 to 2.0 is more preferable, and 0.15 to 1.5 is still more preferable.
  • the stretching stress in the first stretching is small, the amount of deformation of the silver halide grains is small and the effect of stretching several times cannot be obtained, so the stretching stress in the first stretching (vertical stress in the stretching direction) is 10 kgf / cm 2 The above is preferable.
  • n 1 is preferably 1.25 or more, and 1.5 The above is more preferable, and 2.0 or more is still more preferable.
  • n 1 ⁇ n 2 is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more.
  • n 1 is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.
  • FIG. 7 also shows the maximum value of the angle deviation of the polarization axis between various points in the plane of the polarizing glass thus superposed, and an element (optical isolator, liquid crystal) using the polarizing glass. It also shows the relationship with the limit value of the contrast ratio that can be secured over the entire surface of the display element or the like.
  • the absolute value of the difference in polarization axis angle between two points on the polarizing glass is preferably within 0.20 °, and is within 0.16 °. Is more preferable, and it is still more preferable that it is within 0.10 °. When these are converted into angles per unit length, they are within 0.01 ° / mm, within 0.008 ° / mm, and within 0.005 ° / mm, respectively.
  • the absolute value of the difference in the angle of the polarization axis between two points 20 mm apart is preferably 0.20 ° or less, and it is 0.16 ° between two points 15 mm apart. More preferably, it is more preferably 0.10 ° or less between two points 10 mm apart.
  • Example 1 ⁇ Manufacture of base glass> 49.8, B 2 O 3:: 21.3, Al 2 O 3: SiO 2 weight% 6.9, ZrO 2: 8.5, Li 2 O: 5.0, Na 2 O: 5.0 , K 2 O: 4.2, Ag: 0.43, Cl: 0.30, Br: 0.13, a base glass was prepared (represented as composition A in Table 1). That is, the raw materials mixed so as to give the respective compositions were melted at 1450 ° C. in a 2000 cc platinum crucible, then poured into a mold, and once cooled to below the glass transition point, a base glass block was obtained. The produced glass had a glass transition point of 503 ° C., a load softening point of 557 ° C. (measured by TMA), and a refractive index nd of 1.527.
  • the base glass block was heat-treated in an electric furnace maintained at 720 ° C. for 4 hours to produce a heat-treated base glass block.
  • This heat-treated base glass was cloudy white due to the precipitation of silver halide crystals.
  • the grain size of the precipitated silver halide crystals was measured for the heat-treated base glass.
  • the measurement procedure is as follows. That is, the heat-treated base glass was broken to obtain a smooth surface. The resulting smooth surface was etched with a 5 wt% HF aqueous solution for 15 seconds. A spherical hole formed by selectively dissolving the precipitated particle portion was observed with a scanning electron microscope (SEM). The average particle size (number average particle size) at this time was 130 nm.
  • the preform glass was processed into a plate shape having a width of 100 mm, a thickness of 4 mm, and a length of 800 mm.
  • ⁇ Reduction treatment> The stretched glass was cut into a length direction of 10 mm, precisely polished to a thickness of 0.2 mm, and subjected to hydrogen reduction treatment.
  • the reduction treatment was performed at 480 ° C. for 4 hours while flowing 100% hydrogen gas at a flow rate of 10 ml / min under atmospheric pressure.
  • ⁇ Evaluation of deviation of polarization axis angle> A collimator beam, which was linearly polarized through a Glan-Thompson prism, was incident on the polarizing glass, and the polarizing glass was rotated to record the angle at which the amount of transmitted light was minimized.
  • the polarization axis angle at the center of the plate is defined as 0 °, and the relative value of the polarization axis angle at each position in the width direction of the plate is defined as described above with reference to FIG.
  • stretching direction in FIG. 3 is an extending
  • Example 2 After the same preform as in Example 1 was stretched under the conditions shown in Table 1, reduction treatment and evaluation were performed in the same manner as in Example 1.
  • Tables 1 to 3 and FIGS. 4 to 6 show the stretching conditions and optical characteristics of Examples 1 to 6 and Comparative Examples 1 to 5 described above.
  • the present invention makes it easier to manufacture a polarizing glass with a significantly reduced polarization axis deviation as compared with the prior art, a polarizing glass with less deviation in the angle of the polarization axis is provided at a lower cost than before. enable.

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  • Engineering & Computer Science (AREA)
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Abstract

Disclosed is a method for producing polarizing glass that reduces the deviance of the angle of the polarization axis in polarizing glass, and which is a simpler method than the conventional one. Said method contains a step (a) for preparing glass that contains dispersed metal halide particles, a step (b) for obtaining glass that contains dispersed and arranged shape-anisotropic metal halide particles that are transformed in a prescribed direction by applying a load onto said glass when the same is in a heated and softened state, and a step (c) for reducing said shape-anisotropic metal halide particles in the glass into shape-anisotropic metal particles, wherein the step (b) is repeated at least once, and during at least one performing of the repeated step (b), the transformation direction of said glass is the opposite direction of the direction in which said glass was transformed during the first time that the step (b) was performed.

Description

偏光ガラスの製造方法Manufacturing method of polarizing glass
　本発明は光アイソレータ，液晶表示素子等に使用される偏光子を製造する方法に関する。 The present invention relates to a method of manufacturing a polarizer used for an optical isolator, a liquid crystal display element or the like.
　無機系吸収型の偏光子として，形状異方性の金属銀粒子を分散して含んだ偏光子の基本的な製造方法が特許文献１，２に示されている。これらの方法はＡｇ及びハロゲン（Ｃｌ，Ｂｒ又はＩ）を成分として含むガラスを熱処理してハロゲン化銀粒子を析出させた後，そのガラスを押し出し又は延伸することによって形状異方性ハロゲン化銀粒子を分散して含んだガラスとし，次いでこれを還元処理することにより，形状異方性金属銀粒子を分散して含んだ偏光ガラスとするものである。 As an inorganic absorption type polarizer, Patent Documents 1 and 2 disclose basic methods for producing a polarizer containing dispersed metallic silver particles having shape anisotropy. In these methods, shape-anisotropic silver halide grains are obtained by precipitating silver halide grains by heat treating glass containing Ag and halogen (Cl, Br or I) as components, and then extruding or stretching the glass. Then, the glass is dispersed and contained, and then is subjected to a reduction treatment to obtain a polarizing glass containing dispersed shape anisotropic metallic silver particles.
このようにして作製された偏光ガラスにはガラス板面内の偏光軸の角度にずれが生じることが特許文献３，４に示されている。しかし，特許文献３，４には延伸応力と温度を調整すると良いと記載されているものの，具体的にどのようにすべきかについては記載されていない。 Patent Documents 3 and 4 show that the polarizing glass thus produced has a deviation in the angle of the polarization axis in the glass plate surface. However, Patent Documents 3 and 4 describe that the stretching stress and the temperature should be adjusted, but do not describe how to do it specifically.
　特許文献５には延伸工程において，延伸に使用する加熱炉の温度分布を，延伸方向に垂直な方向の両端部で温度が低くなるように設定することで延伸時の幅方向端部におけるガラスの冷却速度を中心部より相対的に速める方法が記載されている。 In Patent Document 5, in the stretching process, the temperature distribution of the heating furnace used for stretching is set so that the temperature becomes lower at both ends in the direction perpendicular to the stretching direction, so that the glass at the end in the width direction during stretching is set. A method for relatively increasing the cooling rate from the center is described.
　特許文献６には延伸工程において，プリフォームが，その延伸部の外形がプリフォームの長手方向に対し５°～２０°の傾斜角度をなして収縮するようにヒータの出力を制御する方法が記載されている。このような方法ではヒータ装置が長くなり，プリフォームの端部が有効利用できず，歩留まりが悪化する。 Patent Document 6 describes a method of controlling the output of the heater in the stretching process so that the outer shape of the preform contracts at an inclination angle of 5 ° to 20 ° with respect to the longitudinal direction of the preform. Has been. In such a method, the heater device becomes long, the end portion of the preform cannot be effectively used, and the yield deteriorates.
　特許文献７には延伸工程において，延伸されたガラスの幅がほぼ一定となるよう，延伸時の板の側縁が延伸方向に対してなす角度を０．０７５°未満に維持するよう，延伸速度やを制御しつつ延伸することが記載されている。しかしながら，そのための具体的手段としては，延伸のための１対のローラーの回転を同期させることや，母材ガラスの量に応じてローラーの回転速度を変えることが記載されているに過ぎない。 In Patent Document 7, in the stretching step, the stretching speed is maintained so that the angle formed by the side edges of the plate during stretching with respect to the stretching direction is less than 0.075 ° so that the width of the stretched glass becomes substantially constant. It describes that the film is stretched while being controlled. However, as specific means for that purpose, it is only described to synchronize the rotation of a pair of rollers for stretching and to change the rotation speed of the rollers according to the amount of the base glass.
　特許文献８には延伸工程において，延伸途中のガラスシートを，ノズルからの冷却ガスの吹き付けにより幅方向の中央部のみを強制冷却する方法が記載されている。強制冷却にはガラスを熱応力で破壊させてしまう可能性を高める他，加熱と冷却を同時に行うことは装置のコントロールを複雑化する問題がある。 Patent Document 8 describes a method of forcibly cooling only a central portion in the width direction by blowing a cooling gas from a nozzle on a glass sheet that is being stretched in a stretching process. In addition to increasing the possibility of destroying the glass due to thermal stress, forced cooling has the problem of complicating the control of the device if heating and cooling are performed simultaneously.
　特許文献９には，プリフォーム肉厚が３ｍｍ以上であり，該プリフォームの移動速度を１５ｍｍ／分以下に設定し，かつ，延伸されたガラスシートの引き取り速度を３００ｍｍ／分以下に設定して加熱延伸することを特徴とする製造方法が記載されている。この方法は板の湾曲を防止する方法であり，面内分布を低減するものではない。 In Patent Document 9, the preform thickness is 3 mm or more, the movement speed of the preform is set to 15 mm / min or less, and the take-up speed of the stretched glass sheet is set to 300 mm / min or less. A production method characterized by heating and drawing is described. This method is a method of preventing the bending of the plate and does not reduce the in-plane distribution.
　また偏光子の製造のためのＡｇを含有するガラス組成については，例えば，ＳｉＯ２，Ｂ２Ｏ３，Ａｌ２Ｏ３，アルカリ金属酸化物（Ｒ２Ｏ）などを主成分とするガラスにＡｇ，ハロゲンを添加したものを用いることや，例えば，ハロゲン化金属の粒子を分散して含有させたガラスを用いることが知られている（特許文献１，２，１０～１４）。 In addition, regarding a glass composition containing Ag for manufacturing a polarizer, for example, a glass containing, as a main component, SiO 2 , B 2 O 3 , Al 2 O 3 , alkali metal oxide (R 2 O), or the like is used. It is known to use a material to which halogen is added, for example, to use a glass in which metal halide particles are dispersed and contained ( Patent Documents 1, 2, 10 to 14).
　このように，偏光軸の角度のずれを低減させる方法として特許文献３～９のような方法が開示されているが，それらは，製造工程に適用するには特別な温度制御等を必要とするため，工程が複雑となり製造コストを高めるという問題がある。 As described above, methods such as Patent Documents 3 to 9 are disclosed as methods for reducing the deviation of the angle of the polarization axis, but these require special temperature control or the like to be applied to the manufacturing process. Therefore, there is a problem that the process becomes complicated and the manufacturing cost is increased.
米国特許４２８２０２２号公報US Pat. No. 4,282,222 米国特許４４７９８１９号公報US Pat. No. 4,479,819 米国特許７１１０１７９号公報US Pat. No. 7,110,179 米国特許７２３０７６０号公報U.S. Pat. No. 7,230,760 特開２００４－２２４６６０号公報JP 2004-224660 A 米国出願２００６／０１７９８８２号公報US Application No. 2006/0179882 米国出願２００６／０２５２６２８号公報US Application No. 2006/0252628 特開２００７－３０２５０５号公報JP 2007-302505 A 特開２００８－２９９３２９号公報JP 2008-299329 A 米国特許５２５２５２４号公報US Pat. No. 5,252,524 米国特許６６０６８８５号公報US Pat. No. 6,606,885 米国特許６７７７３５９号公報US Pat. No. 6,777,359 米国特許７４６８１４８号公報US Pat. No. 7,468,148 米国特許７５１０９８９号公報US Patent No. 7510989
　上記の背景において，本発明は，偏光ガラスの製造において，得られる偏光ガラス中の偏光軸の角度のずれを低減させるための，従来より簡便な方法の提供を目的とする。 In the above background, an object of the present invention is to provide a simpler method for reducing the deviation of the angle of the polarization axis in the obtained polarizing glass in the production of the polarizing glass.
　従来の単なる延伸方法では，延伸されたガラスの偏光軸（吸収軸）は，図１に示すように中心線から離れた部位におけるほど延伸方向（すなわちガラスプリフォームに延伸荷重が作用する方向）に対して斜め外側に広がるようにずれることを本発明者は確認した。本発明者は更に，図２のように延伸工程を２段階以上に分割し，複数段階目の延伸工程のうち少なくとも１つの段階において，１段階目の延伸方向とは反対の方向に延伸することで，この偏光軸の角度のずれを解消又は低減できることを見出した。本発明はこの発見に基づき更なる検討により完成したものである。 In the conventional simple stretching method, the polarizing axis (absorption axis) of the stretched glass is in the stretching direction (that is, the direction in which the stretching load acts on the glass preform) as it is away from the center line as shown in FIG. On the other hand, the present inventor confirmed that it shifted so as to spread obliquely outward. The inventor further divides the stretching process into two or more stages as shown in FIG. 2, and stretches in the direction opposite to the stretching direction of the first stage in at least one of the plurality of stretching processes. Thus, it has been found that the deviation of the angle of the polarization axis can be eliminated or reduced. The present invention has been completed by further studies based on this discovery.
　すなわち本発明は以下を提供する。
　１．ハロゲン化金属粒子を分散して含有するガラスを準備するステップ(a)と，該ガラスに加熱軟化状態で荷重を負荷することにより所定方向に変形させて形状異方性ハロゲン化金属粒子を分散・配向して含有したガラスを得るステップ(b)と，該ガラス中の形状異方性ハロゲン化金属粒子を形状異方性金属粒子へと還元するステップ(c)とを含む偏光ガラスの製造方法において，ステップ(b)を少なくとも１回反復し，反復されるステップ(b)のうち少なくとも１回において，該ガラスを変形させる方向を，ステップ(b)の初回において該ガラスを変形させたのとは反対の方向とすることを特徴とする製造方法。
　２．ステップ(b)における該ガラスの変形が延伸により行われるものである，上記１に記載の製造方法。
　３．ステップ(b)が１回反復されるものである，上記１又は２に記載の製造方法。
　４．ステップ(b)における，初回の該ガラスの延伸倍率をｎ１，２回目の延伸倍率をｎ２とするとき，ｎ１／ｎ２が０．０５～３．０である，上記３に記載の製造方法
　５．ｎ１×ｎ２が５以上である上記４に記載の製造方法
　６．ｎ１が２０以下である上記４又は５に記載の製造方法。
　７．ステップ(b)における初回の延伸応力が１０ｋｇｆ／ｃｍ２以上である，上記４ないし６の何れかに記載の製造方法。
　８．金属が銀である，上記１ないし７の何れかに記載の製造方法。
　９．上記１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて２０ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．２０°以下である，製造方法。
　１０．上記１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて１５ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．１６°以下である，製造方法。
　１１．上記１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて１０ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．１０°以下である，製造方法。
　１２．上記９ないし１１の何れかの製造方法で製造された偏光ガラス。 That is, the present invention provides the following.
1. Step (a) of preparing a glass containing metal halide particles dispersed therein, and dispersing the shape-anisotropic metal halide particles by deforming the glass in a predetermined direction by applying a load in a heat-softened state. In a method for producing a polarizing glass comprising the steps (b) of obtaining glass containing orientation and reducing (c) the shape-anisotropic metal halide particles in the glass to shape-anisotropic metal particles , Step (b) is repeated at least once, and in at least one of the repeated steps (b), the direction in which the glass is deformed is the first time in step (b) that the glass is deformed. A manufacturing method characterized in that the directions are opposite.
2. 2. The production method according to 1 above, wherein the deformation of the glass in step (b) is performed by stretching.
3. 3. The production method according to 1 or 2 above, wherein step (b) is repeated once.
4). 4. In step (b), when the first draw ratio of the glass is n 1 and the second draw ratio is n 2 , n 1 / n 2 is 0.05 to 3.0. 4. Manufacturing method 5. The production method according to 4 above, wherein n 1 × n 2 is 5 or more. 6. The production method according to 4 or 5 above, wherein n 1 is 20 or less.
7). 7. The production method according to any one of 4 to 6 above, wherein the initial stretching stress in step (b) is 10 kgf / cm 2 or more.
8). 8. The production method according to any one of 1 to 7 above, wherein the metal is silver.
9. 9. The method for producing a polarizing glass according to any one of 1 to 8 above, wherein an absolute value of a difference in polarization axis angle between two points 20 mm apart in the obtained polarizing glass is 0.20 ° or less. Production method.
10. 9. The method for producing a polarizing glass according to any one of 1 to 8 above, wherein an absolute value of a difference in polarization axis angle between two points 15 mm apart in the obtained polarizing glass is 0.16 ° or less. Production method.
11. 9. The method for producing a polarizing glass according to any one of 1 to 8, wherein an absolute value of a difference in polarization axis angle between two points separated by 10 mm in the obtained polarizing glass is 0.10 ° or less. Production method.
12 A polarizing glass produced by any one of the above production methods 9 to 11.
　本発明によれば，延伸により製造した偏光ガラス中に偏光軸の角度のずれが残るのを，簡便な方法で解消又は低減することができる。 According to the present invention, it is possible to eliminate or reduce the deviation of the angle of the polarization axis in the polarizing glass produced by stretching by a simple method.
従来の延伸方法で発生する偏光軸の角度のずれを示す模式図Schematic diagram showing the deviation of the polarization axis angle generated by the conventional stretching method 本発明において偏光軸の角度のずれの２段階の延伸による解消を示す模式図Schematic diagram showing the elimination of the deviation of the polarization axis angle by two-stage stretching in the present invention 偏光軸の角度の定義を示す概念図。The conceptual diagram which shows the definition of the angle of a polarization axis. 実施例１～２，比較例１～２の偏光軸の角度のずれを表すグラフGraph showing the deviation of the angle of the polarization axis of Examples 1-2 and Comparative Examples 1-2 実施例３，比較例３～４の偏光軸の角度のずれを表すグラフGraph showing the deviation of the angle of the polarization axis of Example 3 and Comparative Examples 3 to 4 実施例４～６，比較例５の偏光軸の角度のずれを表すグラフGraph showing the deviation of the angle of the polarization axis of Examples 4 to 6 and Comparative Example 5 偏光軸の交差角度のずれの大きさとコントラスト比（＝入射光量／透過光量）との関係を示すグラフA graph showing the relationship between the magnitude of the deviation of the polarization axis crossing angle and the contrast ratio (= incident light quantity / transmitted light quantity)
　本発明において，「偏光軸の角度のずれ」とは，偏光ガラスにおいて，図３に示すように，偏光ガラスの中心線から横方向（プラス方向又はマイナス方向）に離れるにつれ，その部位での偏光軸（吸収軸）の方向が，延伸方向に対し斜め方向にずれることをいう。図３に示すように，偏光ガラスの中心線からの横方向位置は，便宜上図面右方をプラス，左方をマイナスとして表示する。また，偏光ガラスの各部位において，偏光軸の角度のずれの大きさ〔θ〕は，延伸方向に対し偏光軸がなす角の大きさで示し，そのずれが延伸方向に対して，同様に便宜上，半時計回りの場合をプラス，時計回りの場合をマイナスとして表示する。 In the present invention, the “polarization axis angle shift” means that the polarization at the portion of the polarizing glass increases as it moves away from the center line of the polarizing glass in the lateral direction (plus or minus direction) as shown in FIG. This means that the direction of the axis (absorption axis) is shifted obliquely with respect to the stretching direction. As shown in FIG. 3, for the sake of convenience, the horizontal position from the center line of the polarizing glass is displayed with the right side of the drawing as plus and the left side as minus. In each part of the polarizing glass, the magnitude [θ] of the deviation of the angle of the polarization axis is indicated by the angle formed by the polarization axis with respect to the stretching direction. , Displays counterclockwise as positive and clockwise as negative.
　なお，上述のことから明らかなように，偏光軸の角度のずれを問題とするのは，偏光ガラス面上の位置に依存して偏光軸の角度に「変動」があると性能に悪影響を及ぼすためである。従って，偏光ガラス面上の離れた２点でのそれぞれの偏光軸の角度の間に存在する差（の絶対値）又はこれを当該２点間の距離で割って得られる単位長さ当たりの偏光軸の角度変化こそが実際の評価対象であり，上述の横方向位置や偏光軸の角度についての正負方向の取り方，中心線の両端の上下の取り方，及び偏光ガラスの表裏何れの側から観測するかは，何れも本質的に任意である。それらをどのように取るかは最終結果に反映しないからである。 As is clear from the above, the deviation of the angle of the polarization axis is a problem because there is a “variation” in the angle of the polarization axis depending on the position on the polarizing glass surface. Because. Therefore, the difference (absolute value) existing between the angles of the respective polarization axes at two distant points on the polarizing glass surface, or the polarization per unit length obtained by dividing this by the distance between the two points. The change in the angle of the axis is the actual object of evaluation. From the above-mentioned lateral position and the direction of the polarization axis, how to take the positive and negative directions, how to take the upper and lower sides of the center line, and the front and back sides of the polarizing glass Any observation is essentially arbitrary. This is because how to take them does not reflect the final result.
　本発明において母材ガラスとしては，還元して金属粒子とすることのできるハロゲン化金属粒子を含んだ種々のものを使用することができる。例えば，ＳｉＯ２，Ｂ２Ｏ３，Ａｌ２Ｏ３，アルカリ金属酸化物（Ｒ２Ｏ）などを主成分とするガラスにＡｇ，ハロゲンを添加したものを用いることができる。また例えば，ハロゲン化金属の粒子を分散して含有させたガラスを用いることも知られている。それらのガラス組成は，例えば米国特許４２８２０２２号公報（特許文献１），米国特許４４７９８１９号公報（特許文献２），米国特許５２５２５２４号公報（特許文献１０），米国特許６６０６８８５号公報（特許文献１１），米国特許６７７７３５９号公報（特許文献１２），米国特許７４６８１４８号公報（特許文献１３），又は米国特許７５１０９８９号公報（特許文献１４）に記載されており，本発明において母材ガラスの組成として採用してよいが，それらに限定されない。 In the present invention, various glass containing metal halide particles that can be reduced to metal particles can be used as the base glass. For example, a glass mainly composed of SiO 2 , B 2 O 3 , Al 2 O 3 , alkali metal oxide (R 2 O) or the like with Ag and halogen added can be used. For example, it is also known to use a glass in which metal halide particles are dispersedly contained. For example, US Pat. No. 4,282,202 (Patent Document 1), US Pat. No. 4,479,819 (Patent Document 2), US Pat. No. 5,252,524 (Patent Document 10), US Pat. No. 6,606,885 (Patent Document 11). , US Pat. No. 6,777,359 (Patent Document 12), US Pat. No. 7,468,148 (Patent Document 13), or US Pat. No. 7510989 (Patent Document 14), and used as the composition of the base glass in the present invention. However, it is not limited to them.
　より具体的な例を挙げると，組成として，
ＳｉＯ２：２０～６７重量％
Ｂ２Ｏ３：１４～３５重量％
Ａｌ２Ｏ３：０～２５重量％
Ｐ２Ｏ５：０～２５重量％
Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ＋Ｃｓ２Ｏ：４～２０重量％
を主成分とするガラスをベースとして好適に使用することができる。 As a more specific example, as a composition,
SiO 2 : 20 to 67% by weight
B 2 O 3 : 14 to 35% by weight
Al 2 O 3 : 0 to 25% by weight
P 2 O 5 : 0 to 25% by weight
Li 2 O + Na 2 O + K 2 O + Cs 2 O: 4 to 20% by weight
Can be suitably used as a base.
　これらのガラスに含有させる銀及びハロゲンとしては，例えば，
Ａｇ：０．０５～１．５重量％，
Ｃｌ＋Ｂｒ：Ａｇの化学当量以上，
等とすることができるが，この範囲に限定されない。 Examples of silver and halogen contained in these glasses include:
Ag: 0.05 to 1.5% by weight,
Cl + Br: more than the chemical equivalent of Ag,
However, it is not limited to this range.
　他に，任意成分として，ＭｇＯ，ＣａＯ，ＳｒＯ，ＢａＯ，ＺｎＯ，ＰｂＯ，ＴｉＯ２，ＺｒＯ２，Ｎｂ２Ｏ５，Ｌａ２Ｏ３，Ｃｕ２Ｏ，ＣｅＯ２，Ｓｂ２Ｏ３，Ｆ等を適宜含有してもよい。 Other, as optional components, MgO, CaO, SrO, BaO , ZnO, PbO, TiO 2, ZrO 2, Nb 2 O 5, La 2 O 3, Cu 2 O, the CeO 2, Sb 2 O 3, F , etc. You may contain suitably.
　なお，本願の出願人は，現時点で未公開の特許出願（特願２００９－１３６２０９）において，次の組成を有するガラスを偏光子の製造に好適に使用できること，特に当該ガラスを延伸後，加熱下において１気圧の水素雰囲気下で短時間に還元処理できることを確認している。 In addition, the applicant of the present application, in an unpublished patent application (Japanese Patent Application No. 2009-136209), can use a glass having the following composition suitably for manufacturing a polarizer, and in particular, after stretching the glass, It has been confirmed that the reduction treatment can be performed in a short time in a hydrogen atmosphere of 1 atm.
ＳｉＯ２：
４０～６３重量％
Ｂ２Ｏ３：  １５～２６重量％
Ａｌ２Ｏ３：  ５～１５重量％
ＺｒＯ２：   ７～１２重量％
Ｒ１ ２Ｏ：    ４～１６重量％
（Ｒ１は，Ｌｉ，Ｎａ，Ｋ及びＣｓ包括的に表し，但し，Ｌｉ２Ｏ：０～５重量％，Ｎａ２Ｏ：０～９重量％，Ｋ２Ｏ：０～１２重量％，Ｃｓ２Ｏ：０～６重量％である。）
Ｒ２Ｏ：      ０～７重量％
（但し，Ｒ２は，Ｍｇ，Ｃａ，Ｓｒ及びＢａを包括的に表し，但し，ＭｇＯ：０～３重量％，ＣａＯ：０～３重量％，ＳｒＯ：０～５重量％，ＢａＯ：０～５重量％である。）
ＺｎＯ：    ０～６重量％
Ａｇ：      ０．４～１．５重量％
Ｃｌ：      ０．１～１．０重量％
Ｂｒ：      ０．０１～０．５重量％
Ｆ：        ０～０．２重量％
ＴｉＯ２を１．７重量％を超えて含有せず，
Ａｇを０．４重量％以上含有し，且つ，
該偏光ガラスに含まれるＡｇ及びハロゲンの間に，
モル比で，Ａｇ／（Ｃｌ＋Ｂｒ）が０．２～１．０
モル比で，Ｃｌ／（Ｃｌ＋Ｂｒ＋Ｆ）が０．５～０．９５，及び
モル比で，Ｂｒ／（Ｃｌ＋Ｂｒ＋Ｆ）が０．０５～０．４ SiO 2 :
40-63 wt%
B 2 O 3 : 15 to 26% by weight
Al 2 O 3 : 5 to 15% by weight
ZrO 2 : 7 to 12% by weight
R 1 2 O: 4 to 16% by weight
(R 1 represents Li, Na, K and Cs comprehensively, provided that Li 2 O: 0 to 5 wt%, Na 2 O: 0 to 9 wt%, K 2 O: 0 to 12 wt%, Cs 2 O: 0 to 6% by weight.)
R 2 O: 0 to 7% by weight
(However, R 2 comprehensively represents Mg, Ca, Sr and Ba, provided that MgO: 0 to 3 wt%, CaO: 0 to 3 wt%, SrO: 0 to 5 wt%, BaO: 0 to 5% by weight.)
ZnO: 0 to 6% by weight
Ag: 0.4 to 1.5% by weight
Cl: 0.1 to 1.0% by weight
Br: 0.01 to 0.5% by weight
F: 0 to 0.2% by weight
Does not contain TiO 2 exceeds 1.7 wt%,
Containing 0.4 wt% or more of Ag, and
Between Ag and halogen contained in the polarizing glass,
The molar ratio of Ag / (Cl + Br) is 0.2 to 1.0.
The molar ratio Cl / (Cl + Br + F) is 0.5 to 0.95, and the molar ratio Br / (Cl + Br + F) is 0.05 to 0.4.
　母材ガラス組成が上記の組成範囲となるように各種酸化物，ハロゲン化物，水酸化物，硝酸塩，硫酸塩，炭酸塩等，原料を調合し，周知の方法を用いて溶融する。ガラス融液を鋳型に流し出し，成形し，熱処理を行ってハロゲン化銀粒子を析出させることができる。 The raw materials such as various oxides, halides, hydroxides, nitrates, sulfates and carbonates are prepared and melted using a known method so that the glass composition of the base material is in the above composition range. The glass melt can be poured into a mold, molded, and heat treated to precipitate silver halide grains.
　本発明において，ガラスを変形させるステップは，２回のみでも十分であるが，３回以上行っても同様の効果を得ることができる。但し，製造工程の簡素化のためには，２回のみとすることが好ましい。 In the present invention, the step of deforming the glass is sufficient only two times, but the same effect can be obtained even if it is performed three times or more. However, in order to simplify the manufacturing process, it is preferable to use only two times.
　変形ステップのうち最後に行われるものが，偏光ガラスの吸収極大波長に最も大きな影響を与える。延伸によりガラスを変形させる場合，最終段階での延伸はガラスの粘度が１０６～１０９Poiseとなる温度で，５０～５００ｋｇｆ／ｃｍ２の応力をかけて行うのが好ましい。この延伸により，ガラス中のハロゲン化銀粒子も延伸されて，形状異方性となる。延伸は，ハロゲン化銀粒子のアスペクト比の平均値（個数平均）が少なくとも２：１以上になるように行うのが好ましい。アスペクト比に特に上限はなく，目的に応じて適宜設定することができる。 The last of the deformation steps has the greatest effect on the absorption maximum wavelength of the polarizing glass. When the glass is deformed by stretching, the stretching in the final stage is preferably performed at a temperature at which the glass has a viscosity of 10 6 to 10 9 Poise and a stress of 50 to 500 kgf / cm 2 . By this stretching, the silver halide grains in the glass are also stretched to become shape anisotropy. The stretching is preferably performed so that the average aspect ratio (number average) of silver halide grains is at least 2: 1. There is no particular upper limit to the aspect ratio, and it can be set appropriately according to the purpose.
　偏光軸の角度のずれを低減するには，最初の延伸での延伸倍率をｎ１，２回目の延伸での延伸倍率をｎ２とするとき，ｎ１／ｎ２が０．０５～３．０であることが好ましく，０．１～２．０であることがより好ましく，０．１５～１．５であることが更に好ましい。 In order to reduce the deviation of the angle of the polarization axis, n 1 / n 2 is 0.05 to 3 when the stretching ratio in the first stretching is n 1 and the stretching ratio in the second stretching is n 2 . 0 is preferable, 0.1 to 2.0 is more preferable, and 0.15 to 1.5 is still more preferable.
　最初の延伸における延伸応力が小さい場合，ハロゲン化銀粒子の変形量が小さく，複数回延伸の効果が得られないため，最初の延伸での延伸応力（延伸方向の垂直応力）は１０ｋｇｆ／ｃｍ２以上であることが好ましい。 When the stretching stress in the first stretching is small, the amount of deformation of the silver halide grains is small and the effect of stretching several times cannot be obtained, so the stretching stress in the first stretching (vertical stress in the stretching direction) is 10 kgf / cm 2 The above is preferable.
　同様に，最初の延伸における延伸倍率が小さい場合，ハロゲン化銀粒子の変形量が小さく，複数回延伸の効果が得られないため，ｎ１は１．２５以上であることが好ましく，１．５以上がより好ましく，２．０以上が更に好ましい。 Similarly, when the draw ratio in the first drawing is small, the deformation amount of the silver halide grains is small and the effect of drawing a plurality of times cannot be obtained. Therefore, n 1 is preferably 1.25 or more, and 1.5 The above is more preferable, and 2.0 or more is still more preferable.
　生産効率を高めるためにはｎ１×ｎ２が５以上であることが好ましく，１０以上であることがより好ましく，２０以上であることが更に好ましい。 In order to increase production efficiency, n 1 × n 2 is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more.
　製造装置をコンパクトにするためには，ｎ１は２０以下であることが好ましく，１５以下であることがよりこの好ましく，１０以下であることが更に好ましい。 In order to make the manufacturing apparatus compact, n 1 is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.
　延伸したガラスを，ガラス転移点以下の温度にて，水素雰囲気で還元処理する。この還元処理により，少なくともガラスの表面層に存する形状異方性のハロゲン化金属（例えば銀）粒子が形状異方性の金属（例えば銀）粒子へと変換される。こうして得られる形状異方性金属粒子を少なくとも表面層に含んだガラスは，偏光特性を示す。なおここに，形状異方性金属粒子について，「少なくとも表面層に含んだ」とは，ガラスの中心部のハロゲン化銀までが全て金属粒子へと変換される必要が無いことを示すに過ぎず，特定の厚みの層でなければならないことを意味しない。 還 元 Reduce the stretched glass in a hydrogen atmosphere at a temperature below the glass transition point. By this reduction treatment, at least the shape-anisotropic metal halide (for example, silver) particles existing in the surface layer of the glass are converted into shape-anisotropic metal (for example, silver) particles. The glass containing the shape anisotropic metal particles thus obtained in at least the surface layer exhibits polarization characteristics. Here, with respect to shape anisotropic metal particles, “at least included in the surface layer” merely indicates that it is not necessary to convert all the silver halide at the center of the glass into metal particles. , Does not mean that it must be a layer of a certain thickness.
　２つの理想的な偏光子をそれらの偏光軸が互いに約９０°で交差するように重ね合わせ，第一の偏光子を透過する偏光を入射した場合，透過光量は，Malusの法則に従って偏光軸の交差の角度が９０°からずれているほど増大する。その角度のずれの大きさと，コントラスト比（＝入射光量／透過光量）との関係は図７のようになる。従ってまた，図７は，そのように重ね合わせた偏光ガラス面内の様々な点の間での偏光軸の角度ずれの大きさの最大値と，その偏光ガラスを利用した素子（光アイソレータ，液晶表示素子等）の面内全域で確保可能なコントラスト比の限界値との関係も示している。 When two ideal polarizers are superposed so that their polarization axes cross each other at about 90 °, and the polarized light passing through the first polarizer is incident, the amount of transmitted light is determined according to Malus's law. It increases as the angle of intersection deviates from 90 °. The relationship between the magnitude of the angle deviation and the contrast ratio (= incident light quantity / transmitted light quantity) is as shown in FIG. Accordingly, FIG. 7 also shows the maximum value of the angle deviation of the polarization axis between various points in the plane of the polarizing glass thus superposed, and an element (optical isolator, liquid crystal) using the polarizing glass. It also shows the relationship with the limit value of the contrast ratio that can be secured over the entire surface of the display element or the like.
　例えば，偏光軸が互いに約９０°で交差するように重ね合わせた２枚の偏光ガラス面内の様々な点での偏光軸の角度のずれ（絶対値）が０．１°以下であれば，偏光子面内全域にわたり５５ｄＢまでの性能を得ることができ，０．０５°以下であれば６０ｄＢまでの性能を得ることができる。 For example, if the deviation (absolute value) of the polarization axis at various points in the two polarizing glass surfaces superimposed so that the polarization axes cross each other at about 90 ° is 0.1 ° or less, Performance up to 55 dB can be obtained over the entire polarizer plane, and performance up to 60 dB can be obtained at 0.05 ° or less.
　本発明においては，偏光ガラス上の，例えば２０ｍｍ離れた２点における偏光軸の角度の差の絶対値は，０．２０°以内に収まっているのが好ましく，０．１６°以内に収まっているのがより好ましく，０．１０°以内に収まっているのが更に好ましい。これらは単位長さ当たりの角度に換算すると，それぞれ，０．０１°／ｍｍ以内，０．００８°／ｍｍ以内，０．００５°／ｍｍ以内である。 In the present invention, the absolute value of the difference in polarization axis angle between two points on the polarizing glass, for example, 20 mm apart, is preferably within 0.20 °, and is within 0.16 °. Is more preferable, and it is still more preferable that it is within 0.10 °. When these are converted into angles per unit length, they are within 0.01 ° / mm, within 0.008 ° / mm, and within 0.005 ° / mm, respectively.
　また，本発明においては，２０ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．２０°以下であることが好ましく，１５ｍｍ離れた２点間でのそれが０．１６°以下であることがより好ましく，１０ｍｍ離れた２点間でのそれが０．１０°以下であることが更に好ましい。 In the present invention, the absolute value of the difference in the angle of the polarization axis between two points 20 mm apart is preferably 0.20 ° or less, and it is 0.16 ° between two points 15 mm apart. More preferably, it is more preferably 0.10 ° or less between two points 10 mm apart.
以下，本発明の偏光子の製造方法について，実施例を参照して説明するが，本発明がそれら実施例に限定されることは意図しない。特に，以下は本発明の実施形態を延伸工程で説明しているが，押し出し法等，これ以外の変形方法においても同様に適用することが可能である。
　なお，実施例１，２および比較例１，２は赤外領域用偏光ガラスの製造，実施例３～６および比較例３～５は可視光領域用偏光ガラスの製造を意図したものである。 Hereinafter, although the manufacturing method of the polarizer of this invention is demonstrated with reference to an Example, this invention is not intended to be limited to these Examples. In particular, the following describes the embodiment of the present invention in the stretching process, but the present invention can be similarly applied to other deformation methods such as an extrusion method.
Examples 1 and 2 and Comparative Examples 1 and 2 are intended for the production of infrared polarizing glass, and Examples 3 to 6 and Comparative Examples 3 to 5 are intended for the production of visible light polarizing glass.
〔実施例１〕
＜母材ガラスの製造＞
　重量％でＳｉＯ２：４９．８，Ｂ２Ｏ３：２１．３，Ａｌ２Ｏ３：６．９，ＺｒＯ２：８．５，Ｌｉ２Ｏ：５．０，Ｎａ２Ｏ：５．０，Ｋ２Ｏ：４．２，Ａｇ：０．４３，Ｃｌ：０．３０，Ｂｒ：０．１３の組成からなる母材ガラスを作製した（表１において組成Ａとして表す）。すなわち，それぞれの組成を与えるように混合した原料を２０００ｃｃの白金坩堝にて１４５０℃で溶解した後，鋳型に流し込み，ガラス転移点以下まで一旦冷却し，母材ガラスブロックを得た。作製したガラスのガラス転移点は５０３℃，荷重軟化点は５５７℃（ＴＭＡで測定），屈折率ｎｄは１．５２７であった。 [Example 1]
<Manufacture of base glass>
49.8, B 2 O 3:: 21.3, Al 2 O 3: SiO 2 weight% 6.9, ZrO 2: 8.5, Li 2 O: 5.0, Na 2 O: 5.0 , K 2 O: 4.2, Ag: 0.43, Cl: 0.30, Br: 0.13, a base glass was prepared (represented as composition A in Table 1). That is, the raw materials mixed so as to give the respective compositions were melted at 1450 ° C. in a 2000 cc platinum crucible, then poured into a mold, and once cooled to below the glass transition point, a base glass block was obtained. The produced glass had a glass transition point of 503 ° C., a load softening point of 557 ° C. (measured by TMA), and a refractive index nd of 1.527.
　この母材ガラスブロックを７２０℃に保持した電気炉中で４時間熱処理を行い，熱処理済母材ガラスブロックを作製した。この熱処理済母材ガラスは，ハロゲン化銀結晶の析出によって白色に濁っていた。 The base glass block was heat-treated in an electric furnace maintained at 720 ° C. for 4 hours to produce a heat-treated base glass block. This heat-treated base glass was cloudy white due to the precipitation of silver halide crystals.
　また，熱処理済母材ガラスについて，析出したハロゲン化銀結晶の粒径の計測を行った。計測の手順は次のとおりである。すなわち，熱処理済母材ガラスを破断して平滑面を得た。得られた平滑面を５重量％ＨＦ水溶液で１５秒間エッチングした。析出粒子部分が選択的に溶解してできる球形の孔を走査型電子顕微鏡（ＳＥＭ）で観察して行った。このときの平均粒子径（個数平均粒子径）は１３０ｎｍであった。熱処理済母材ガラスを幅１００ｍｍ×厚さ４ｍｍ×長さ８００ｍｍの板状に加工し，プリフォームを得た。 Also, the grain size of the precipitated silver halide crystals was measured for the heat-treated base glass. The measurement procedure is as follows. That is, the heat-treated base glass was broken to obtain a smooth surface. The resulting smooth surface was etched with a 5 wt% HF aqueous solution for 15 seconds. A spherical hole formed by selectively dissolving the precipitated particle portion was observed with a scanning electron microscope (SEM). The average particle size (number average particle size) at this time was 130 nm. The preform glass was processed into a plate shape having a width of 100 mm, a thickness of 4 mm, and a length of 800 mm.
＜延伸＞
　このプリフォームを，粘度が約１０８ｄＰａ・ｓとなる６２０℃まで加熱し，挿入速度４ｍｍ／分，引出速度２０ｍｍ／分で延伸した。このときの引張荷重は６４ｋｇｆであった。延伸後の断面は幅約５０ｍｍ×厚さ約１．６ｍｍであった。
　次に，挿入方向と引出方向を逆にして，６００℃まで加熱し，挿入速度４ｍｍ／ｍｉｎ，引出速度２０ｍｍ／ｍｉｎで２段階目の延伸を行った。このときの引張荷重は３９ｋｇｆであった。延伸後の断面は幅約２３ｍｍ×厚さ約０．７ｍｍであった。 <Extension>
This preform was heated to 620 ° C. at which the viscosity was about 10 8 dPa · s, and stretched at an insertion speed of 4 mm / min and a drawing speed of 20 mm / min. The tensile load at this time was 64 kgf. The cross section after stretching was about 50 mm wide and about 1.6 mm thick.
Next, the insertion direction and the drawing direction were reversed, and heating was performed to 600 ° C., and the second stage drawing was performed at an insertion speed of 4 mm / min and a drawing speed of 20 mm / min. The tensile load at this time was 39 kgf. The cross section after stretching was about 23 mm wide by about 0.7 mm thick.
＜還元処理＞
　延伸したガラスを長さ方向１０ｍｍに切断し，０．２ｍｍ厚に精密研磨し，水素還元処理を施した。還元処理は，大気圧下で１００％水素ガスを流量１０ｍｌ／分でフローしながら４８０℃で４時間行った。 <Reduction treatment>
The stretched glass was cut into a length direction of 10 mm, precisely polished to a thickness of 0.2 mm, and subjected to hydrogen reduction treatment. The reduction treatment was performed at 480 ° C. for 4 hours while flowing 100% hydrogen gas at a flow rate of 10 ml / min under atmospheric pressure.
＜吸収極大波長の評価＞
　こうして得られた偏光ガラスについて，グラントムソンプリズムを設置した分光光度計で透過率を測定した。吸収極大波長は約１５００ｎｍであった。 <Evaluation of absorption maximum wavelength>
The transmittance of the polarizing glass thus obtained was measured with a spectrophotometer equipped with a Glan-Thompson prism. The absorption maximum wavelength was about 1500 nm.
＜偏光軸角度のずれの評価＞
　グラントムソンプリズムを介して直線偏光としたコリメータビームを偏光ガラスに入射させ，偏光ガラスを回転させて透過光量が最小となる角度を記録した。板の中央での偏光軸角度を０°として，板の幅方向の各位置における偏光軸角度の相対値を図３を参照して前述したとおりに定義する。なお，図３における延伸方向は，最後の延伸での延伸方向である。 <Evaluation of deviation of polarization axis angle>
A collimator beam, which was linearly polarized through a Glan-Thompson prism, was incident on the polarizing glass, and the polarizing glass was rotated to record the angle at which the amount of transmitted light was minimized. The polarization axis angle at the center of the plate is defined as 0 °, and the relative value of the polarization axis angle at each position in the width direction of the plate is defined as described above with reference to FIG. In addition, the extending | stretching direction in FIG. 3 is an extending | stretching direction in the last extending | stretching.
〔実施例２〕
　実施例１と同じプリフォームを用い，表１にある条件で延伸を行った後，還元処理および評価は実施例１と同様に行った。 [Example 2]
After the same preform as in Example 1 was stretched under the conditions shown in Table 1, reduction treatment and evaluation were performed in the same manner as in Example 1.
〔実施例３～６〕
＜母材ガラスの製造＞
　重量％でＳｉＯ２：４９．８，Ｂ２Ｏ３：２１．３，Ａｌ２Ｏ３：６．９，ＺｒＯ２：８．５，Ｌｉ２Ｏ：５．０，Ｎａ２Ｏ：５．０，Ｋ２Ｏ：４．２，Ａｇ：０．４３，Ｃｌ：０．２２，Ｂｒ：０．１３，Ｆ：０．０４の組成からなる母材ガラスを作製し（表２～３において組成Ｂとして表す），６８０℃に保持した電気炉中で４時間熱処理を行った。このときのハロゲン化銀の平均粒径は５０ｎｍであった。
表２にある条件で延伸を行った後，還元処理および評価は実施例１と同様に行った。 [Examples 3 to 6]
<Manufacture of base glass>
49.8, B 2 O 3:: 21.3, Al 2 O 3: SiO 2 weight% 6.9, ZrO 2: 8.5, Li 2 O: 5.0, Na 2 O: 5.0 , K 2 O: 4.2, Ag: 0.43, Cl: 0.22, Br: 0.13, F: 0.04, a base material glass was prepared (composition B in Tables 2 to 3). The heat treatment was performed in an electric furnace maintained at 680 ° C. for 4 hours. The average grain size of the silver halide at this time was 50 nm.
After stretching under the conditions shown in Table 2, reduction treatment and evaluation were performed in the same manner as in Example 1.
〔比較例１～５〕
　表１～３に示す条件で，延伸は1度のみ行い，還元処理および評価は実施例１と同様に行った。 [Comparative Examples 1 to 5]
Under the conditions shown in Tables 1 to 3, stretching was performed only once, and reduction treatment and evaluation were performed in the same manner as in Example 1.
　上記各実施例１～６及び比較例１～５につき，それらの延伸条件及び光学特性を，表１～３及び図４～６に示す。 Tables 1 to 3 and FIGS. 4 to 6 show the stretching conditions and optical characteristics of Examples 1 to 6 and Comparative Examples 1 to 5 described above.
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000001
  
Figure JPOXMLDOC01-appb-T000002
  
Figure JPOXMLDOC01-appb-T000002
  
Figure JPOXMLDOC01-appb-T000003
  
Figure JPOXMLDOC01-appb-T000003
  
　表１～３および図４～６に示すとおり，実施例１～６によれば，対応する比較例に比べて，偏光軸の角度のずれの遥かに小さい偏光ガラスが得られる。 As shown in Tables 1 to 3 and FIGS. 4 to 6, according to Examples 1 to 6, it is possible to obtain a polarizing glass having a much smaller deviation of the polarization axis angle than the corresponding comparative example.
　本発明は，偏光軸のずれを顕著に低減させた偏光ガラスの製造が従来に比して容易となるため，偏光軸の角度のずれが少ない偏光ガラスを，従来より低コストで提供することを可能にする。 Since the present invention makes it easier to manufacture a polarizing glass with a significantly reduced polarization axis deviation as compared with the prior art, a polarizing glass with less deviation in the angle of the polarization axis is provided at a lower cost than before. enable.
１＝母材ガラス
２＝ハロゲン化金属
３＝偏光軸（吸収軸） 1 = base glass 2 = metal halide 3 = polarization axis (absorption axis)

Claims (12)

  1. 　ハロゲン化金属粒子を分散して含有するガラスを準備するステップ(a)と，該ガラスに加熱軟化状態で荷重を負荷することにより所定方向に変形させて形状異方性ハロゲン化金属粒子を分散・配向して含有したガラスを得るステップ(b)と，該ガラス中の形状異方性ハロゲン化金属粒子を形状異方性金属粒子へと還元するステップ(c)とを含む偏光ガラスの製造方法において，ステップ(b)を少なくとも１回反復し，反復されるステップ(b)のうち少なくとも１回において，該ガラスを変形させる方向を，ステップ(b)の初回において該ガラスを変形させたのとは反対の方向とすることを特徴とする製造方法。 Step (a) of preparing a glass containing dispersed metal halide particles, and dispersing the shape anisotropic metal halide particles by deforming the glass in a predetermined direction by applying a load in a heat-softened state. In a method for producing a polarizing glass comprising the steps (b) of obtaining glass containing orientation and reducing (c) the shape-anisotropic metal halide particles in the glass to shape-anisotropic metal particles , Step (b) is repeated at least once, and in at least one of the repeated steps (b), the direction in which the glass is deformed is the first time in step (b) that the glass is deformed. A manufacturing method characterized in that the directions are opposite.
  2. 　ステップ(b)における該ガラスの変形が延伸により行われるものである，請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the deformation of the glass in step (b) is performed by stretching.
  3. 　ステップ(b)が１回反復されるものである，請求項１又は２に記載の製造方法。 The manufacturing method according to claim 1 or 2, wherein step (b) is repeated once.
  4. 　ステップ(b)における，初回の該ガラスの延伸倍率をｎ１，２回目の延伸倍率をｎ２とするとき，ｎ１／ｎ２が０．０５～３．０である，請求項３に記載の製造方法 In step (b), when the draw ratio n 1, 2 nd stretching ratio of the glass of the first to n 2, n 1 / n 2 is 0.05 to 3.0, according to claim 3 Manufacturing method
  5. 　ｎ１×ｎ２が５以上である請求項４に記載の製造方法 The manufacturing method according to claim 4, wherein n 1 × n 2 is 5 or more.
  6. 　ｎ１が２０以下である請求項４又は５に記載の製造方法。 The manufacturing method according to claim 4, wherein n 1 is 20 or less.
  7. 　ステップ(b)における初回の延伸応力が１０ｋｇｆ／ｃｍ２以上である，請求項４ないし６の何れかに記載の製造方法。 The production method according to any one of claims 4 to 6, wherein the initial stretching stress in step (b) is 10 kgf / cm 2 or more.
  8. 　金属が銀である，請求項１ないし７の何れかに記載の製造方法。 The manufacturing method according to any one of claims 1 to 7, wherein the metal is silver.
  9. 　請求項１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて２０ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．２０°以下である，製造方法。 The method for producing a polarizing glass according to any one of claims 1 to 8, wherein an absolute value of an angle difference of polarization axes between two points 20 mm apart in the obtained polarizing glass is 0.20 ° or less. ,Production method.
  10. 　請求項１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて１５ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．１６°以下である，製造方法。 The method for producing a polarizing glass according to any one of claims 1 to 8, wherein an absolute value of a difference in polarization axis angle between two points 15 mm apart in the obtained polarizing glass is 0.16 ° or less. ,Production method.
  11. 　上記１ないし８の何れかに記載の偏光ガラスの製造方法であって，得られる偏光ガラスにおいて１０ｍｍ離れた２点間での偏光軸の角度の差の絶対値が０．１０°以下である，製造方法。 9. The method for producing a polarizing glass according to any one of 1 to 8, wherein an absolute value of a difference in polarization axis angle between two points separated by 10 mm in the obtained polarizing glass is 0.10 ° or less. Production method.
  12. 　請求項９ないし１１の何れかの製造方法で製造された偏光ガラス。 A polarizing glass produced by the production method according to claim 9.
PCT/JP2011/057472 2010-03-29 2011-03-25 Method for producing polarizing glass WO2011122500A1 (en)

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JP2016038500A (en) * 2014-08-08 2016-03-22 日本電気硝子株式会社 Method for manufacturing polarizing glass plate

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WO2015198934A1 (en) * 2014-06-26 2015-12-30 日本電気硝子株式会社 Polarizing glass plate and method for manufacturing same, polarizing glass plate set for optical isolator, and method for manufacturing optical element for optical isolator
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