JP2006242972A - Birefringent wavelength body, projection device provided with the same, pickup, and manufacturing method of birefringent wavelength body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a birefringent wavelength body having high durability and high reliability. <P>SOLUTION: The birefringent wavelength body 1 comprises a main material 2 principally comprising glass and a plurality of light transparent sub-materials 3 which are dispersedly incorporated into the main material 2. The sub-materials 3 are formed in an elongated shape and are oriented such that the longitudinal directions are directed substantially in the same direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a birefringent wave body, a projection apparatus including the birefringent wave body, a pickup, and a method for manufacturing the birefringent wave body.

  As a birefringent wave plate that is currently in practical use, it has a structure in which polymer bond chains with different refractive indices (having birefringence) are oriented in a specific direction by stretching a resin film. A resin birefringent wavelength film may be mentioned. In the birefringent wavelength film made of resin, since the minute polymer bond chains are oriented in a predetermined direction, the refractive index in the macroscopic direction of the polymer bond chain and the direction perpendicular to the orientation direction is macroscopically as a whole film. Is different. For this reason, the resin birefringent wavelength film functions as a birefringent wavelength plate.

  On the other hand, for example, Patent Document 1 discloses a birefringent wave plate made of glass. The birefringent wave plate described in Patent Document 2 is formed of stretched glass exhibiting a large birefringence, and silver halide particles having a high aspect ratio and aligned in the same direction are coaxially arranged in the glass matrix. Are distributed.

Although different from the birefringent wave plate, Patent Document 2 discloses that resin molding is performed by adding birefringent needle-like crystals to the resin so as to offset the birefringence that occurs when ordinary resins are molded. Techniques for reducing the birefringence of articles are disclosed. It also describes controlling birefringence.
JP-A-5-188221 JP 2004-109355 A

  The birefringent wave plate made of resin has a problem that its life is short in a high-temperature environment, an environment where a strong light beam (in particular, blue, purple, or ultraviolet light) is incident, or an environment where a high-temperature and strong light beam is incident. . This is because the resin that is the material of the birefringent wavelength plate is deteriorated or damaged by heat or light, and specifically, problems such as discoloration, a decrease in transmittance, and fluctuations in the birefringence value occur. is there.

  A resin birefringent wave plate has a relatively large coefficient of thermal expansion and a relatively low mechanical strength. For this reason, when mounting a birefringent wave plate on an optical device, the birefringent wave plate is likely to be distorted. When an optical device equipped with a birefringent wave plate is used for a long time, the birefringent wave plate itself or There is a problem that deformation of peripheral objects tends to occur. In addition, since the resin has a relatively large photoelastic constant, there is also a problem that when the resin-made birefringent wave plate is distorted, the birefringence value of the birefringent wave plate greatly changes due to the photoelastic effect.

  Resin-made birefringent wavelength plates are often as thin as about 0.05 to 0.3 mm, and have a problem that they are flexible and easy to bend, are difficult to handle when mounted on optical devices, and are easily damaged. In order to improve the handleability and scratch resistance, a high-strength resin or glass is sometimes used by being bonded to a resin birefringent wavelength plate, and there is a problem that the structure is complicated and the number of manufacturing steps is increased.

  On the other hand, the birefringent wave plate made of glass disclosed in Patent Document 2 is produced by precipitating silver halide particles having a high aspect ratio (needle-like) by heat treatment. However, when silver halide particles are precipitated by the annealing process, it is difficult to control the particle size and particle concentration of the silver halide particles. Therefore, there is a problem that it is difficult to control the birefringence value. Further, since silver halide particles dispersed in a glass matrix do not transmit light, the birefringent wavelength plate disclosed in Patent Document 2 has a problem that it is difficult to realize sufficient light transmittance.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a birefringent wavelength body having high reliability.

  The birefringent wavelength body according to the present invention includes a main material mainly composed of glass and a plurality of light-transmitting sub-materials dispersed and mixed in the main material. Each of the plurality of sub-materials is formed in an elongated shape, and each of the plurality of sub-materials is oriented so that the longitudinal direction thereof is directed in substantially the same direction. In addition, in this invention, light transmittance means that the transmittance | permeability of the light of the wavelength range of 500 nm-700 nm is 50% or more. More specifically, light having a wavelength range of 500 nm to 700 nm is incident on a plate material having a thickness of 1 mm (both surfaces mirror-polished) made of substantially the same material as an object to be measured (for example, a secondary material). In this case, it means that 50% or more of incident light is emitted.

  In the birefringent wavelength body according to the present invention, the main component of the main material is glass, and substantially no organic matter is contained. For this reason, the birefringent wavelength body according to the present invention has higher heat resistance and light resistance than the resin-made birefringent wavelength body. In particular, when the auxiliary material is formed of an inorganic material, high heat resistance is obtained. This is because, when the secondary material is made of an inorganic material, the difference between the thermal expansion coefficient of the secondary material and the thermal expansion coefficient of the main material mainly composed of glass is smaller than that of the birefringent wavelength body made of resin.

  Since glass is harder and stronger than resin, the birefringent wavelength body according to the present invention is hard to be scratched and has excellent handleability. Therefore, the birefringent wavelength body according to the present invention does not require a protective substrate and has a simple structure. In addition, since glass has relatively higher mechanical strength and smaller photoelastic constant than resin, the birefringent wavelength body according to the present invention has an amount of change in birefringence value with respect to distortion during mounting or distortion generated over time. Is relatively less than conventional resin birefringent wave bodies. Further, compared to the case where the main material is a resin, a more uniform (without striae) birefringent wavelength body can be realized by using glass as the main component of the main material.

  In the birefringent wavelength body according to the present invention, a plurality of sub-materials (for example, rod-shaped sub-materials) formed in an elongated shape are dispersed and mixed in the main material, and each of the plurality of sub-materials has substantially the same direction. Is oriented. For this reason, the refractive index can be made different between the orientation direction of the secondary material and the direction orthogonal thereto. Therefore, the birefringent wavelength body according to the present invention has birefringence. From the viewpoint of clarifying the birefringence direction, the ratio of the length in the longitudinal direction to the length in the short direction (hereinafter sometimes referred to as “aspect ratio”) is preferably 1.5 or more. This is because, when the aspect ratio is 1.5 or more, the orientation of the secondary material can be improved, so that a large birefringence can be realized.

  In the birefringent wavelength body according to the present invention, the secondary material has optical transparency. For this reason, the birefringent wavelength body according to the present invention has higher light transmittance than a birefringent wavelength body in which the secondary material does not have light transmittance.

  In the birefringent wavelength body according to the present invention, each of the plurality of sub-materials may have birefringence. By using the secondary material having birefringence, the birefringence of the birefringent wavelength body can be further increased.

  In the birefringent wavelength body according to the present invention, it is preferable that the length of each of the plurality of secondary materials in the short direction is 700 nm or less. According to this configuration, it is possible to suppress incident light from being irregularly reflected inside the birefringent wavelength body. Therefore, a birefringent wavelength body having high light transmittance can be realized.

  In the birefringent wave body according to the present invention, the plurality of secondary materials are one or more selected from the group consisting of alkaline earth metal carbonates (strontium carbonate, calcium carbonate, barium carbonate, etc.) and titanium oxide. Crystals containing as a main component may be included. Specifically, each of the plurality of secondary materials may be a crystal mainly composed of one or two or more materials selected from the group consisting of various alkaline earth metal carbonates and titanium oxides. . In addition, in the main material, a plurality of types of secondary materials including crystals mainly composed of one or more materials selected from the group consisting of carbonates of various alkaline earth metals and titanium oxide are dispersed and mixed. You may let them. Alkaline earth metal carbonates and titanium oxide have a large birefringence and can easily obtain rod-like crystals having a relatively large particle size. Therefore, according to this configuration, it is possible to realize a birefringent wavelength body that has large birefringence and is easy to manufacture. Moreover, according to this structure, the difference between the thermal expansion coefficient of the main material and the thermal expansion coefficient of the secondary material can be made relatively small. For this reason, it has a relatively high durability even in an environment where the temperature changes drastically.

  In the birefringent wavelength body according to the present invention, the difference between the refractive index of the main material and the refractive index of the secondary material may be 0.1 or more. According to this configuration, a birefringent wavelength body having a large birefringence can be realized. In addition, in this specification, the refractive index of a secondary material means the value which averaged the refractive index in the longitudinal direction of a secondary material, and the refractive index in the transversal direction of a secondary material.

  In the birefringent wavelength body according to the present invention, the main material may be composed mainly of phosphate. According to this configuration, the melting point (MP) and glass transition temperature (Tg) of the main material can be lowered. Therefore, an easily manufactured birefringent wavelength body can be realized.

  The projection apparatus according to the present invention includes the birefringent wavelength body according to the present invention. As described above, the birefringent wavelength body according to the present invention is excellent in durability such as heat resistance and light resistance. Therefore, the projection apparatus according to the present invention having the birefringent wavelength body according to the present invention is also highly durable and has a long product life. Further, the projection apparatus according to the present invention can exhibit stable performance against temperature changes and the like.

  The pickup according to the present invention has the birefringent wavelength body according to the present invention. Similar to the projection apparatus according to the present invention, the pickup according to the present invention is also excellent in durability such as heat resistance and light resistance. In addition, the pickup according to the present invention can exhibit stable performance against temperature changes and the like.

  The method for producing a birefringent wavelength body according to the present invention includes a main material mainly composed of glass, and a plurality of light-transmitting auxiliary materials dispersed and mixed in the main material, each of the plurality of auxiliary materials being The present invention relates to a method for producing a birefringent wavelength body formed in an elongated shape. The method for producing a birefringent wavelength body according to the present invention includes a base material forming step for forming a base material formed by dispersing and mixing a plurality of sub-materials in a main material, and a stretching process step for stretching the base material in one direction. Including.

  In the method for manufacturing a birefringent wavelength body according to the present invention, the base material is formed by dispersing and mixing the plurality of sub-materials into the main material. For this reason, the amount of the secondary material to be dispersed and mixed, the size and the shape (aspect ratio, etc.) of the secondary material can be arbitrarily controlled. Therefore, according to the manufacturing method according to the present invention, the birefringence of the birefringent wavelength body to be manufactured can be arbitrarily controlled.

  Immediately after the completion of the base material forming step, the plurality of sub-materials included in the formed base material does not yet have a certain orientation, and the sub-materials are oriented in random directions. Thereafter, in the stretching process, the base material is stretched in a predetermined direction, whereby each of the plurality of sub-materials can be oriented in substantially the same direction. Therefore, according to the manufacturing method according to the present invention, a birefringent wavelength body having birefringence can be preferably manufactured. In the present invention, the stretching process is not limited to the process of stretching the base material (extension processing process) as long as the base material is stretched in a specific direction. For example, a process of extending the base material in one direction by extruding from between rollers arranged at a predetermined interval (roller rolling process), a process of extending the base material in one direction by press molding with a die (press processing process) Or the like. In any of the extension process, the roller rolling process, and the pressing process, the secondary material can be similarly oriented in substantially the same direction.

  In the birefringent wavelength body according to the present invention, the stretching process may be performed a plurality of times. By performing the stretching process a plurality of times, the orientation of the secondary material can be improved, and a birefringent wavelength body having a larger birefringence can be produced. The stretching process performed a plurality of times may be any of an extension process, a roller rolling process, and a pressing process. A plurality of types of processes selected from the stretching process, the roller rolling process, and the pressing process may be combined.

  As described above, according to the present invention, a birefringent wavelength body having high durability and high reliability can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, a birefringent wave plate and a manufacturing method thereof according to Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a birefringent wavelength body 1 according to Embodiment 1. FIG. FIG. 2 is a schematic diagram showing a microscopic structure of the birefringent wavelength body 1. FIG. 3 is an enlarged view of the secondary material 3. The birefringent wave body 1 includes a main material 2 formed in a rectangular plate shape and a plurality of sub-materials 3 dispersed and mixed in the main material 2. The secondary material 3 is formed in an elongated shape (for example, a long dimension of about 200 nm and a short dimension of about 100 nm). Note that the secondary material 3 is not shown in FIG.

  In the birefringent wave body 1, the plurality of sub-materials 3 dispersed in the main material 2 are substantially oriented in the direction 4 shown in FIG. 1. In other words, the plurality of sub-materials 3 are oriented so that their longitudinal directions are directed in the substantially same direction 4. For this reason, in the birefringent wave body 1, the refractive index in the direction 4 is different from the refractive index in the direction orthogonal to the direction 4. That is, the birefringent wavelength body 1 has birefringence. The secondary material 3 is preferably oriented so that the longitudinal direction is in the same direction. However, in the present invention, the secondary material 3 is not necessarily oriented so that the longitudinal direction is completely in the same direction. There is no.

  When incident light 5 that is linearly polarized light having a polarization direction rotated by 45 degrees with respect to the slow axis 4 that is the direction of the largest refractive index is incident on the birefringent wavelength body 1 having birefringence, the birefringence wavelength When passing through the body 1, a predetermined phase difference is given to the incident light 5, and outgoing light 6 whose polarization direction is rotated with respect to the incident light 5 is emitted from the birefringent wavelength body 1. Beginner Here, when the outgoing light 6 rotated by 90 degrees with respect to the incident light 5 is obtained, the birefringent wavelength body 1 functions as a half-wave plate. When circularly polarized outgoing light having a polarization direction distributed with respect to linearly polarized incident light 5 is obtained, the birefringent wavelength body 1 functions as a quarter wavelength plate.

  In the first embodiment, the birefringent wavelength body 1 is formed in a rectangular plate shape. The layer thickness of the birefringent wave body 1 formed in a plate shape can be, for example, 0.1 mm or more and 3 mm or less. In addition, the shape of the birefringent wavelength body according to the present invention is not limited to a plate shape, and may be, for example, a lens shape, a cubic shape, a rectangular parallelepiped shape, a spherical shape, an elliptical shape, or the like.

  The main material 2 is mainly composed of glass and substantially does not contain organic substances. For this reason, the birefringent wavelength body 1 has higher heat resistance and light resistance (high reliability) than a resin-made birefringent wavelength body.

  Since the glass is harder and stronger than the resin, the birefringent wavelength body 1 is hard to be scratched and has excellent handleability. Also, unlike conventional products, no matter where it is gripped, it will not be distorted greatly. For this reason, the birefringent wavelength body 1 is easy to handle and can be easily mounted on an optical device.

  The birefringent wave body 1 has excellent light resistance, and the glass that is the main component of the main material 2 has relatively higher mechanical strength and a smaller photoelastic constant than the resin. For this reason, the birefringent wavelength body 1 has a relatively small amount of change in the birefringence value with respect to mounting distortion or distortion generated over time. Furthermore, glass has little crystallinity and anisotropy and is homogeneous and transparent. For this reason, the birefringent wave body 1 is excellent in light transmittance and has high optical anisotropy (high birefringence).

  The glass that can be the main component of the main material 2 is not limited at all, but preferably has a low melting point. By using a glass having a low melting point (MP) (hereinafter sometimes referred to as “low melting point glass”) as a main component of the main material 2, it is possible to realize a birefringent wavelength body 1 that is easy to manufacture. Because it can. Low melting point glass suitable as the main component of the main material 2 includes phosphate glass mainly containing phosphate, borosilicate glass containing alkali metal element and alkaline earth metal element, lead oxide-containing glass, oxidation Bismuth containing glass etc. are mentioned. In addition, the melting point of glass and the glass transition temperature are correlated, and generally a glass having a low melting point has a low glass transition temperature. More preferably, a glass having a glass transition temperature of 250 ° C. or higher and 700 ° C. or lower is used as the main component of the main material 2. The glass transition temperature can be measured, for example, by a thermomechanical analyzer (TMA60) manufactured by Shimadzu Corporation.

  The secondary material 3 dispersed in the main material 2 has light transmittance. For this reason, compared with the birefringent wavelength body using the secondary material which does not have a light transmittance, the birefringent wavelength body 1 which concerns on this Embodiment 1 has a high transmittance | permeability. In addition, light transmittance means that the transmittance | permeability of the light of the wavelength range of 500 nm-700 nm is 50% or more. The light transmittance of the secondary material 3 is obtained by forming a plate material sample having a layer thickness of 1 mm (both surfaces mirror-polished) made of substantially the same material as the secondary material 3 and 500 nm to 700 nm of the plate material sample. Can be measured with a spectrophotometer (UV3150) manufactured by Shimadzu Corporation.

  The secondary material 3 may have birefringence. By dispersing the secondary material 3 having birefringence in the main material 2, the birefringent wave body 1 having a larger birefringence can be realized.

  The secondary material 3 preferably has a length L1 in the longitudinal direction (see FIG. 3) of 1.5 times or more the length L2 in the lateral direction. In other words, the ratio (aspect ratio: L1 / L2) between the length L1 in the longitudinal direction and the length L2 in the lateral direction is preferably 1.5 or more. By setting the aspect ratio to 1.5 or more, the orientation of the secondary material 3 can be further improved. Therefore, the birefringent wave body 1 having a larger birefringence can be realized. The length L1 in the longitudinal direction is preferably 10 times or less the length L2 in the short direction.

  The length L2 in the short direction is preferably shorter than the wavelength of light incident on the birefringent wavelength body 1. This is because scattering of incident light by the secondary material 3 can be effectively suppressed, and the birefringent wavelength body 1 having high light transmittance can be realized. For example, the length L2 in the short direction can be 10 nm or more and 700 nm or less.

  In the birefringent wavelength body 1, the birefringence of the birefringent wavelength body 1 can be controlled to an arbitrary value by changing the aspect ratio (L1 / L2) of the secondary material 3. The birefringence of the birefringent wave body 1 can be increased as the aspect ratio is increased, and conversely, the birefringence of the birefringent wave body 1 can be decreased by decreasing the aspect ratio.

  The concentration of the secondary material 3 with respect to the main material 2 is preferably 0.001 wt% or more and 30 wt% or less. When the concentration of the secondary material 3 is less than 0.001% by weight, it is difficult to obtain a desired birefringence. In the birefringent wave body 1, the birefringence of the birefringent wave body 1 can be controlled to an arbitrary value by changing the concentration of the secondary material 3. The birefringence of the birefringent wavelength body 1 can be increased by increasing the concentration of the secondary material 3, and conversely, the birefringence of the birefringent wavelength body 1 can be decreased by decreasing the concentration of the secondary material 3. be able to.

In the birefringent wavelength body 1, the plurality of secondary materials 3 are alkaline earth metal carbonates (strontium carbonate, calcium carbonate, barium carbonate, etc.), titanium oxide, yttrium vanadate (YVO ₄ ), lithium niobate (LiNbO _3). ), Alpha barium borate (α-BaB ₂ O ₄ ), and a crystal mainly composed of one or more materials selected from the group consisting of calcite. Specifically, each of the plurality of sub-materials 3 may be a crystal mainly composed of one or two or more materials selected from the above group. In addition, a plurality of types of sub-materials containing crystals whose main component is one or more materials selected from the above group may be dispersed and mixed in the main material 2. Of course, the secondary material 3 may not be a single crystal. Alkaline earth metal carbonate, titanium oxide, yttrium vanadate (YVO ₄ ), lithium niobate (LiNbO ₃ ), alpha barium borate (α-BaB ₂ O ₄ ), and calcite have large birefringence and comparison A rod-like crystal having a large target particle size can be easily obtained. For this reason, according to this structure, the birefringent wavelength body 1 which has a large birefringence and is easy to manufacture can be realized. Further, the secondary material 3 may be a crystal.

  In the birefringent wave body 1, the difference between the refractive index of the main material 2 and the refractive index of the auxiliary material 3 may be 0.1 or more. According to this configuration, the birefringent wave body 1 having a large birefringence can be realized. The refractive index of the main material 2 may be 0.1 or more larger than the refractive index of the auxiliary material 3. The refractive index of the main material and the secondary material can be measured with an ellipsometer (FE5000) manufactured by Otsuka Electronics. When the secondary material is a fine particle, the refractive index may be measured using a lump formed of substantially the same material as the secondary material.

  Next, a method for manufacturing the birefringent wavelength body 1 will be described. First, the glass that is the material of the main material 2 is melted, and the secondary material 3 is put into the molten glass. The molten glass is well kneaded and stirred, and the base material 7 is formed by uniformly dispersing the secondary material 3 in the molten glass (base material forming step). FIG. 4 is a schematic diagram showing a microscopic structure of the base material 7 formed by the base material forming step. As shown in FIG. 4, a plurality of secondary materials 3 are dispersed and mixed in the base material 7, but the secondary materials 3 are randomly distributed without being oriented in a specific direction. Therefore, the base material 7 does not have sufficient birefringence. The birefringence wave body 1 having birefringence can be manufactured by performing the following drawing process. In addition, the form of the base material 7 can be determined as appropriate depending on the type of the stretching process performed later. For example, the base material 7 may be in a melted state or may be in a state of being formed and solidified into a predetermined shape. The formed and solidified base material 7 can be formed by casting molten glass mixed with the secondary material 3 into a mold or the like.

  Next, the base material 7 formed by the base material forming step is stretched (stretching step). In this Embodiment 1, the method (roll rolling processing method) of extending | stretching by roll rolling is employ | adopted. However, the present invention is not limited to this method. For example, a method of stretching the base material by stretching (extension processing method), a method of stretching the base material in one direction by press molding using a die (press processing method) Or the like. Moreover, you may carry out combining the roll rolling processing method, the extension processing method, the press processing method, etc.

  FIG. 5 is a conceptual diagram for explaining the base material forming step. In FIG. 5, for convenience of explanation, the orientation state of the secondary material 3 is shown.

  When the base material 7 is stretched by the roll rolling method, the base material 7 is formed into a plate-like body having a layer thickness larger than the layer thickness of the target birefringent wave body 1 in the base material forming step. Is preferred. The layer thickness of the base material 7 before stretching is preferably 2 to 50 times the layer thickness of the birefringent wavelength body 1 to be manufactured.

  In the stretching process, as shown in FIG. 5, first, the base material 7 formed in a thick plate shape is supplied to the roller 10. The supplied base material 7 is pressurized and stretched by a roller 10. The temperature of the base material 7 when supplied to the roller 10 is preferably higher than the strain temperature, and more preferably higher than the softening temperature. The base material 7 formed in the base material forming step may be held at a temperature at which the base material is roll-stretched, and the stretch processing step may be performed. The base material 7 once formed is cooled (annealed) and then heated again. The material 7 may be set to a predetermined temperature.

  The base material 7 is stretched by a roller 10 in a predetermined direction (stretching direction; right direction in FIG. 5), whereby the orientation direction of the secondary material 3 dispersed and mixed in the base material 7 (longitudinal direction of the secondary material 3) is changed. It can be almost aligned in the stretching direction. The base material 7 stretched by the roller 10 is further stretched by the roller 11 (by performing stretching several times), whereby the orientation direction of the secondary material 3 can be further aligned with the stretching direction. In this way, the plate-like body 9 is formed. In the plate-like body 9, as shown in FIG. 2, the secondary material 3 is oriented so that the longitudinal direction thereof faces substantially the same direction. As described above, it is not necessary for all of the sub-materials 3 to completely face the same direction, and there may be some variation in orientation.

  And the birefringent wavelength body 1 can be manufactured by forming the formed plate-like body 9 into a predetermined shape. Further, in order to further improve the surface accuracy of the birefringent wavelength body 1, the upper and lower surfaces (light entrance / exit surfaces) may be polished to a mirror surface. The birefringence value of the birefringent wave body 1 can also be adjusted by processing the plate thickness using the birefringence value measured after the stretching process as a guide.

  In addition, according to the said manufacturing method, the quantity of the submaterial 3 disperse-mixed in a base material formation process, the magnitude | size, shape (aspect ratio etc.) of the submaterial 3 can be controlled arbitrarily. Therefore, the birefringence of the birefringent wave body 1 to be manufactured can be arbitrarily controlled.

As described above, the birefringent wave body 1 according to the first embodiment is excellent in durability such as heat resistance and light resistance. Therefore, the projection apparatus and display apparatus having the birefringent wavelength body 1 also have high durability and a long product life. In addition, the projection apparatus and display apparatus having the birefringent wavelength body 1 can exhibit stable performance against temperature changes and the like. Similarly, the pickup having the birefringent wavelength body 1 is also excellent in durability such as heat resistance and light resistance. In addition, the pickup having the birefringent wavelength body 1 can exhibit stable performance against temperature changes and the like.
(Embodiment 2)
A method for manufacturing a birefringent wavelength body according to Embodiment 2 of the present invention will be described in detail with reference to FIG. FIG. 6 is a schematic diagram for explaining a stretching process in the second embodiment. In the second embodiment, first, glass as a material of the main material 2 is melted, and the secondary material 3 is put into the molten glass. By thoroughly kneading and stirring the molten glass, the secondary material 3 is uniformly dispersed in the glass, and then formed into a plate-like body (base material 12) having a desired size. The thickness of the base material 12 is preferably thicker than the thickness of the birefringent wavelength body 1 to be manufactured. Moreover, it is preferable that the dimension of the base material 12 is larger than the dimension of the birefringent wavelength body 1 to be manufactured. In the second embodiment, the base material 12 is stretched by the following stretching process, but the portion held by the clamp 13 is not stretched and needs to be cut after the stretching process. As the secondary material 3 to be dispersed and mixed in the main material 2, for example, birefringent rod-like particles of calcium carbonate can be used.

  Next, in a state where the base material 12 is held at a predetermined temperature (for example, a glass transition temperature or higher, preferably a strain point or higher), both ends of the base material 12 are held by the clamps 13 and heated and softened by the clamps 13. The material 12 is stretched (stretching process). As shown to Fig.6 (a), before performing an extending | stretching process process, the auxiliary | assistant material 3 is scattered disorderly, without orientating in a specific direction. Therefore, the base material 12 does not have sufficient birefringence. The base material 12 is stretched by the stretching process, whereby the secondary material 3 is substantially oriented in the stretching direction 14 (the longitudinal direction of the secondary material 3 faces substantially the same direction). Therefore, by performing the stretching process, the plate-like body 15 having birefringence with the secondary material 3 oriented in the stretching direction 14 is obtained. The plate thickness of the plate-like body 15 after the drawing process is preferably 1/50 or more and 1/2 or less of the layer thickness of the base material 12 before the drawing process.

  A birefringent wavelength body can be manufactured by processing the plate-like body 15 into a desired shape. Also by the manufacturing method according to the second embodiment, a birefringent wavelength body having the same birefringence property as the manufacturing method according to the first embodiment can be manufactured.

  In the second embodiment, the plate-like body 15 may be stretched again (any of a roll rolling method, an extension processing method, a pressing method, etc.). According to this, it is possible to realize a birefringent wavelength body having a higher orientation of the secondary material 3 and a large birefringence.

(Embodiment 3)
A method for manufacturing a birefringent wavelength body according to Embodiment 3 of the present invention will be described in detail with reference to FIG. FIG. 7 is a schematic diagram for explaining a stretching process in the third embodiment. In the third embodiment, first, the glass that is the material of the main material 2 is melted, and the secondary material 3 (for example, birefringent rod-like particles of titanium oxide) is put into the molten glass. By thoroughly kneading and stirring the molten glass, the secondary material 3 is uniformly dispersed in the glass, and then a desired amount of molten glass containing the secondary material 3 is dropped on the lower mold 18 to form the base material 16 ( Base material forming process). Once the gob-shaped base material 16 is formed, the formed base material 16 may be disposed on the lower mold 18.

  The base material 16 disposed on the lower die 18 is maintained at a desired temperature, and the base material 16 is pressed using the lower die 18 and the upper die 19 (stretching process step). Side walls 20 are provided on the side surfaces (specifically, left and right side surfaces in FIG. 7) of the lower mold 18 and the upper mold 19, and the base material 16 is restricted from extending in the left-right direction in FIG. Long stretched in the direction. That is, in Embodiment 3, the extending direction is the depth direction in FIG. By this stretching process, the secondary material 3 included in the base material 16 is substantially oriented in the stretching direction. Therefore, the birefringent wavelength body 21 having birefringence can also be manufactured by the manufacturing method according to the third embodiment.

  In the third embodiment, the birefringent wave body 21 may be further stretched (any of roll rolling, stretching, pressing, etc.). According to this, it is possible to realize a birefringent wavelength body having a higher orientation of the secondary material 3 and a large birefringence.

(Embodiment 4)
A projection apparatus 22 according to Embodiment 4 of the present invention will be described in detail with reference to FIG. FIG. 8 is a schematic diagram of the projection apparatus 22 according to the fourth embodiment. The projection device 22 includes a lamp 23, a first lens array 24 and a second lens array 25 provided on the light emission direction side of the lamp 23, and a polarization conversion element 26 provided on one surface side of the second lens array 25. , A P birefringence wave body 27 provided on one surface side of the polarization conversion element 26, a synthesis prism 30, and a mirror 28 appropriately disposed so that light emitted from the lamp 23 enters the synthesis prism 30; 31 and an R dichroic mirror 29, and a projection lens 32 provided on the light emitting direction side of the combining prism 30. Between the mirror 31 and the composite prism 30, a laminated body X including an R polarizing plate 33, an R liquid crystal panel 34, an R birefringent wavelength body 35, and an R polarizing plate 36 is provided from the mirror 31 side. A laminated body Y including a G liquid crystal panel 37 is provided so as to face the projection lens 32 with the synthetic prism 30 interposed therebetween, and a B polarizing plate 38 so as to face the R polarizing plate 36 with the synthetic prism 30 interposed therebetween. A laminated body Z including a B liquid crystal panel 39, a B birefringent wavelength body 40, and a B polarizing plate 41 is provided.

  In the projection device 22, the white light emitted from the lamp 23 is converted into a light flux having a uniform light amount distribution by the first lens array 24 and the second lens array 25. The light beam is converted into a linearly polarized light beam in a predetermined polarization direction by the polarization conversion element 26 to which a plurality of P birefringence wave bodies 27 are attached. This linearly polarized light beam is bent in the traveling direction by the mirror 28 and enters the R dichroic mirror 29.

  The R dichroic mirror 29 transmits only red light of incident light and reflects light of other colors (blue light and green light). For this reason, red light out of the white linearly polarized light incident on the R dichroic mirror 29 is emitted toward the mirror 31. On the other hand, blue light and green light are reflected by the R dichroic mirror 29. The red light transmitted through the R dichroic mirror 29 is reflected by the mirror 31 toward the synthesis prism 30, is modulated into red image light by the stacked body X, and then enters the synthesis prism 30. On the other hand, the green light reflected by the R dichroic mirror 29 enters the laminate Y. The incident light is modulated into green image light by the laminated body Y and is incident on the combining prism 30. The blue light reflected by the R dichroic mirror 29 enters the laminate Z. The incident light is modulated into blue image light by the laminate Z and enters the combining prism 30.

  The red, green, and blue image lights incident on the combining prism are combined by the combining prism 30 and emitted in the direction of the projection lens 32, and the image light is projected on the screen by the action of the projection lens 32.

  In the projection device 22, the birefringent wavelength bodies described in the first embodiment are used as the birefringent wavelength bodies 27, 35, and 40. As described above, the birefringent wavelength body according to the first embodiment is excellent in durability such as heat resistance and light resistance. Thus, the projection device 22 is also highly durable and has a long product life. Further, the projection device 22 can exhibit stable performance against temperature changes and the like.

  As described above, the birefringent wavelength body of the present invention is excellent in heat resistance, light resistance, scratch resistance, and handleability. As a half-wave plate or a quarter-wave plate, liquid crystal projectors and optical disk pickups are used. It can be used for liquid crystal panels.

1 is a perspective view of a birefringent wavelength body 1 according to Embodiment 1. FIG. 1 is a schematic diagram showing a microscopic structure of a birefringent wavelength body 1. FIG. It is an enlarged view of the secondary material 3. FIG. It is a schematic diagram which shows the microscopic structure of the base material 31 formed by the base material formation process. It is a conceptual diagram for demonstrating a base material formation process. 6 is a schematic diagram for explaining a stretching process in Embodiment 2. FIG. 10 is a schematic diagram for explaining a stretching process in Embodiment 3. FIG. It is a schematic diagram of the projection apparatus 22 which concerns on this Embodiment 4. FIG.

Explanation of symbols

1,21 Birefringent wavelength body
2 Main materials
3 Secondary materials
7, 16 Base material
9 Plate
10, 11 Roller
12 Base material
13 Clamp
15 Plate
18 Lower mold
19 Upper mold
20 side walls
22 Projector
23 Lamp
24 First lens array
25 Second lens array
26 Polarization conversion element
27P birefringent wave body
28, 31 mirror
29 R dichroic mirror
30 synthetic prism
32 Projection lens
33 R polarizing plate
34 R LCD panel
35 R birefringent wave body
36 R polarizing plate
37 G LCD panel
38 B Polarizer
39 B LCD panel
40 B birefringence wave body
41 B polarizing plate

Claims (11)

A main material mainly composed of glass;
A plurality of light-transmitting sub-materials dispersed and mixed in the main material;
Including
Each of the plurality of sub-materials is formed in an elongated shape,
Each of the plurality of sub-materials is a birefringent wavelength body that is oriented so that its longitudinal direction is directed in substantially the same direction. In the birefringent wavelength body according to claim 1,
Each of the plurality of secondary materials is a birefringent wavelength body having birefringence. In the birefringent wavelength body according to claim 1,
Each of the plurality of sub-materials is a birefringent wavelength body in which the ratio of the length in the longitudinal direction to the length in the lateral direction is 1.5 or more. In the birefringent wavelength body according to claim 1,
A birefringent wavelength body in which the length in the short direction of each of the plurality of secondary materials is 700 nm or less. In the birefringent wavelength body according to claim 1,
The plurality of sub-materials is a birefringent wavelength body containing a crystal having as a main component one or more materials selected from the group consisting of strontium carbonate, calcium carbonate, barium carbonate, and titanium oxide. In the birefringent wavelength body according to claim 1,
A birefringent wavelength body in which a difference between a refractive index of the main material and a refractive index of the auxiliary material is 0.1 or more. In the birefringent wavelength body according to claim 1,
The main material is a birefringent wavelength body mainly composed of phosphate.   A projection apparatus comprising the birefringent wavelength body according to claim 1.   A pickup comprising the birefringent wavelength body according to claim 1. A main material mainly composed of glass, and a plurality of light-transmitting sub-materials dispersed and mixed in the main material, each of the plurality of sub-materials having a birefringent wavelength body formed in an elongated shape. A manufacturing method comprising:
A base material forming step of forming a base material formed by dispersing and mixing the plurality of sub-materials in the main material;
A stretching process for stretching the base material in one direction;
A method for producing a birefringent wavelength body comprising: In the manufacturing method of the birefringent wave body according to claim 10,
A method for producing a birefringent wavelength body in which the stretching step is performed a plurality of times.

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