JP2007328262A - Method for manufacturing polarization element, and polarization element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polarization element high in durable reliability without depending on the use environment. <P>SOLUTION: The method for manufacturing the polarization element includes: a film stretching process of stretching a PVA film to manufacture a polarization film; a protective layer adhesion process of adhering a TAC (cellulose triacetate) sheet to at least one surface of the polarization film to manufacture a polarization element body; a deformation regulating process of regulating deformation of the polarization element body; a heating process of heat-treating the polarization element under the heating conditions at a heating temperature of 110°C to 120°C and for two or more hours of heating; and a light-transmitting substrate adhesion process of adhering a light-transmitting substrate to one surface of the heat-treated polarization element body to manufacture the polarization element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polarizing element manufacturing method and a polarizing element.

Conventionally, in an optical apparatus such as a projector, a polarizing element that aligns the polarization axis of an incident light beam has been used.
Such a polarizing element has a configuration in which a polarizing element body is attached to a light-transmitting substrate. The polarizing element body includes a polarizing film that transmits polarized light in a predetermined direction and absorbs polarized light in the other direction among incident light beams, and a protective layer for protecting the polarizing film (for example, Patent Document 1).

  The composite sheet as a polarizing element body described in Patent Document 1 is obtained by laminating a thermoplastic saturated norbornene resin sheet as a protective layer on at least one surface of a polyvinyl alcohol (hereinafter, PVA) sheet as a polarizing film. Configured. When producing this composite sheet, first, a PVA-based film comprising PVA as a main component is stretched to produce a PVA-based sheet, and a thermoplastic saturated norbornene-based resin sheet is bonded to the surface of the PVA-based sheet via an adhesive. Is adhered. And the polarizing element is manufactured by adhere | attaching this composite sheet to a translucent board | substrate.

Japanese Patent Laid-Open No. 5-212828

However, the polarizing film in such a polarizing element has residual stress because it is produced by stretching a PVA-based film as described above. Further, during operation of the optical device, heat is generated in the polarizing element due to absorption of polarized light. Moreover, the case where the humidity around a polarizing element is high is also considered. At this time, the residual stress of the polarizing film increases due to heat, moisture, etc., and the polarizing film may shrink.
When the polarizing film contracts in the polarizing element body, there is a risk that cracks and warpage may occur in the polarizing element body. In particular, when the warping of the polarizing element body is large, the polarizing element body may be peeled from the light transmitting substrate when the adhesive force between the polarizing element body and the light transmitting substrate is weak.
Thus, in a polarizing element, there exists a subject that a crack and a big curvature generate | occur | produce in a polarizing element main body by shrinkage | contraction of a polarizing film by heat | fever, moisture, etc.

  The objective of this invention is providing the manufacturing method of a polarizing element and a polarizing element with high durability reliability irrespective of a use environment.

  In order to achieve the above-described object, the polarizing element manufacturing method of the present invention is bonded to at least one surface of a polarizing film that transmits only polarized light in a predetermined direction among incident light beams, and the polarizing film. A method for producing a polarizing element comprising a polarizing element body having a protective layer and a translucent substrate bonded to at least one surface of the polarizing element body, the polyvinyl alcohol film comprising polyvinyl alcohol as a main component A film stretching step for producing the polarizing film by stretching the film, and a protective layer adhesion for producing the polarizing element body by adhering the protective layer to at least one surface of the polarizing film produced in the film stretching step A deformation regulating step for regulating deformation of the polarizing element body manufactured in the protective layer adhering step, and a deformation regulating step. A heating step of heating the polarizing element body in which the temperature is regulated under a heating condition of a heating temperature of 110 ° C. or more and 120 ° C. or less and a heating time of 2 hours or more, and the polarizing element body heated in the heating step A translucent substrate adhering step of manufacturing a polarizing element by adhering the translucent substrate to at least one of the surfaces;

  Here, as a protective layer, the sheet | seat formed from the cellulose triacetate (TAC) is mentioned, for example. Moreover, as a translucent board | substrate, it can comprise with optical crystal materials, such as quartz or sapphire, for example.

According to the present invention, the polarizing film and the protective layer of the polarizing element body contract by a contraction amount corresponding to the heating temperature by heat-treating the polarizing element body in the heating step. In this way, when the polarizing element is manufactured, the polarizing film is contracted to disperse the residual stress, so that the polarizing film can be contracted even if heat or moisture is generated around the polarizing element during use of the polarizing element. Can be suppressed.
Thus, since shrinkage | contraction of the polarizing film in use of a polarizing element can be suppressed, it can suppress that a crack and a big curvature generate | occur | produce in a polarizing element main body by shrinkage | contraction of a polarizing film. Therefore, it is possible to manufacture a polarization element with high durability and reliability regardless of the use environment.

Furthermore, since the polarizing element body is heated in the heating process in a state where the deformation of the polarizing element body is regulated in the deformation regulating process, it is possible to suppress the polarizing element body from being deformed due to the contraction of the polarizing film by the heating process. it can.
In the present invention, in the heating step, the polarizing element body is subjected to heat treatment under heating conditions of a heating temperature of 110 ° C. or more and 120 ° C. or less and a heating time of 2 hours or more.
Here, when the heat treatment is performed at a heating temperature lower than 110 ° C., it takes a long heating time to shrink the polarizing film to an appropriate shrinkage amount. Furthermore, when the heat treatment is performed at a heating time higher than 120 ° C., the polarizing film is unlikely to shrink, and the stress dispersion efficiency of the polarizing film is reduced.
On the other hand, when the heat treatment is performed at 110 ° C. or higher and 120 ° C. or lower as in the heating step of the present invention, the polarizing film easily contracts and high stress dispersion efficiency can be obtained. That is, it is possible to manufacture a polarizing element having a polarizing element body in which cracks and warpage are unlikely to occur in a relatively short time.

In this invention, it is preferable that the said deformation | transformation control process controls the deformation | transformation of the said polarizing element main body by making the shaping | molding surface of a metal mold | die contact both surfaces of the said polarizing element main body.
Here, for example, a press die composed of two press plates each having a molding surface can be adopted as the die. And a deformation | transformation of a polarizing element main body can be controlled by pinching a polarizing element main body between two press plates of this press type | mold, and making it press in a mutual direction.
According to the present invention, in the deformation regulating step, the deformation of the polarizing element body is regulated by bringing each surface of the polarizing element body into contact with the molding surface of the mold, and the deformation of the polarizing element body is regulated, Heat treatment is performed in the heating step. In this way, the heat treatment can be performed by bringing each surface of the polarizing element body into contact with the molding surface of the mold, and thus the deformation of the polarizing element body can be regulated, and the adhesive strength between the polarizing film of the polarizing element body and the protective layer Can be increased.

  In the present invention, the protective layer adhesion step produces the polarizing element body by adhering the protective layer to any surface of the polarizing film, and the deformation regulation step applies to the polarizing film of the polarizing element body. The polarizing element body is deformed by setting the polarizing element body to a curved surface using the mold in which the molding surface that comes into contact is a concave curved surface and the molding surface that comes into contact with the protective layer is a convex curved surface. It is preferable to regulate.

Here, for example, a press die composed of two press curved plates each having a cylindrical molding surface can be adopted as the die. Then, by sandwiching the polarizing element body between the press-type press curved plates and pressing them together, deformation can be restricted in a state where the polarizing element body is set in a curved surface.
In addition, when the polarizing element body is heat-treated in the heating process, the polarizing element body has a concave concave portion on the polarizing film side (the surface side to which the protective layer is not bonded) because the protective layer is bonded only to one surface of the polarizing film. Easily deformed into a curved surface.
On the other hand, according to the present invention, in the deformation regulating step, the polarizing film surface of the polarizing element body is brought into contact with the concave curved surface of the mold, and the protective layer surface is brought into contact with the convex curved surface. By doing so, the polarizing element body is set in advance in a curved surface shape in which the polarizing film side is convex, and deformation is restricted. Then, after the heat treatment in the heating step, when the polarizing element body is taken out from the mold, the shape of the polarizing element body can be deformed into a flat plate shape by utilizing the contraction of the polarizing film. Therefore, a plate-shaped polarizing element body can be manufactured through the deformation regulation step and the heating step.

  The polarizing element of the present invention includes a polarizing film that transmits only polarized light in a predetermined direction among incident light beams, a polarizing element body having a protective layer bonded to at least one surface of the polarizing film, and the polarized light A polarizing element comprising a translucent substrate bonded to at least one surface of an element body, wherein the polarizing element is manufactured by any one of the manufacturing methods of a polarizing element described above.

  According to the present invention, the polarizing element is a polarizing element manufactured by any one of the above-described polarizing element manufacturing methods. Therefore, depending on the usage environment of the polarizing element, a large warp or crack may occur in the polarizing element body due to contraction of the polarizing film. Can be prevented from occurring. Therefore, the polarizing element can have excellent durability reliability regardless of the use environment.

Embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
[Configuration of Polarizing Plate 5]
First, the structure of the polarizing plate 5 as a polarizing element of this embodiment is demonstrated.
FIG. 1 is a schematic cross-sectional view along the thickness direction of the polarizing plate 5.
As shown in FIG. 1, the polarizing plate 5 has a configuration in which a polarizing element body 52 is attached to a light-transmitting substrate 51 via an adhesive sheet 524.
The translucent substrate 51 suppresses a rapid increase in temperature of the polarizing element body 52 by absorbing and radiating heat generated in the polarizing element body 52. The translucent substrate 51 is formed in a rectangular shape by a material having excellent thermal conductivity and translucency such as sapphire glass or crystal.

  The polarizing element body 52 transmits the transmitted light with its polarization axis aligned in a predetermined direction. As shown in FIG. 1, the polarizing element body 52 is formed by laminating a polarizing film 521 that polarizes transmitted light, and two cellulose triacetate (hereinafter, TAC) sheets 522A and 522B as protective layers that protect the polarizing film 521. It has the structure which was made.

The polarizing film 521 is a rectangular film (polarizing film) that transmits polarized light having a predetermined polarization axis among incident light beams and absorbs polarized light having another polarization axis. The polarizing film 521 is manufactured by stretching a PVA film mainly composed of polyvinyl alcohol (hereinafter referred to as PVA) in one direction and adsorbing and dispersing iodine.
The polarizing film 521 manufactured by stretching a PVA-based film is not particularly limited as long as it has a function as a polarizing film. For example, after diffusion and adsorption of a direct dye having high dichroism on a PVA film, a metal such as gold, silver, mercury, or iron was adsorbed on a PVA / dye polarizing film stretched in one direction and a PVA film. A PVA / metal polarizing film, a near-ultraviolet polarizing film obtained by treating a PVA film with a boric acid solution containing potassium iodide and sodium thiosulfate may be employed.

  The TAC sheets 522 </ b> A and 522 </ b> B are bonded to both surfaces of the polarizing film 521 via an adhesive 523 in order to ensure the durability and mechanical strength of the polarizing film 521. This is because the polarizing film 521 is weak in mechanical strength in the thickness direction, and further has a property that it is easily contracted by heat or moisture and its polarizing function is easily lowered. TAC is a transparent resin having high thermoplasticity.

[Production Method of Polarizing Plate 5]
Next, the manufacturing method of the polarizing plate 5 is demonstrated. FIG. 2 is a flowchart showing a method for manufacturing the polarizing plate 5.
First, as shown in FIG. 2, in process S1, the polarizing film 521 is manufactured from the PVA-type film which has PVA as a main component (S1).
The polarizing film 521 is usually a step of uniaxially stretching a PVA-based film, a step of dyeing this PVA-based film with iodine to adsorb iodine, a step of treating the PVA-based film on which iodine is adsorbed with a boric acid aqueous solution, It is manufactured through a step of washing the PVA film after the treatment with the acid aqueous solution and a step of drying the PVA film.

Uniaxial stretching may be performed before iodine staining, may be performed simultaneously with iodine staining, or may be performed after iodine staining. When uniaxial stretching is performed after iodine staining, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages.
For uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched or uniaxially stretched using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio of the PVA film is usually about 4 to 8 times.

In order to adsorb and orient iodine on the PVA film, a method of immersing and dyeing the PVA film in an aqueous solution containing iodine and potassium iodide is usually employed.
The boric acid treatment after iodine staining is performed by immersing a PVA film dyed with iodine in an aqueous boric acid solution. And the PVA-type film after a boric-acid process is normally washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated PVA film in water. After washing with water, a drying process is performed to obtain a polarizing film 521 in which iodine is adsorbed and oriented.
In addition, this process S1 is corresponded to the film extending process of this invention.

Next, the TAC sheets 522A and 522B are bonded to both surfaces of the polarizing film 521 manufactured by the processing S1 through the adhesive 523, respectively, to manufacture the polarizing element body 52 (S2).
FIG. 3 is a schematic cross-sectional view along the thickness direction of the polarizing element body 52 manufactured in the process S2.
The surface of the TAC sheets 522A and 522B is previously subjected to AR (Anti Reflection) coating. The AR coating treatment is to prevent reflection of external light on the surfaces of the TAC sheets 522A and 522B by coating the surfaces of the TAC sheets 522A and 522B with two types of thin films having different refractive indexes. Furthermore, a protective film (not shown) for preventing damage is attached in advance to the surfaces of the TAC sheets 522A and 522B that are not bonded to the polarizing film 521.
Examples of the adhesive 523 include a polyvinyl alcohol-based adhesive.
In addition, this process S2 is corresponded to the protective layer adhesion process of this invention.

  Next, the protective film on the surface of the TAC sheet 522A is peeled off, and the adhesive sheet 524 is attached to the surface of the TAC sheet 522A (S3). FIG. 4 is a schematic cross-sectional view showing the polarizing element body 52 with the adhesive sheet 524 attached to the surface of the TAC sheet 522A. On the surface of the pressure-sensitive adhesive sheet 524 opposite to the TAC sheet 522A, a release paper 525 is attached in advance to prevent damage and improve workability. In the future, the polarizing element body 52 to which the adhesive sheet 524 and the release paper 525 are attached will be referred to as a polarizing element body 520 with an adhesive sheet.

  And in process S4, a cut process is performed to the polarizing element main body 520 with an adhesive sheet (S4). The cutting process is a process of cutting the polarizing element body 520 with the pressure-sensitive adhesive sheet into an appropriate size according to the use of the polarizing plate 5 (FIG. 1) and dividing it into a plurality of chips.

Next, the polarizing element body 520 with the chip-like pressure-sensitive adhesive sheet is installed in the press die 7A as a mold (S5).
FIG. 5 is a schematic cross-sectional view showing a polarizing element body 520 with an adhesive sheet in the press die 7A.
As shown in FIG. 5, the press die 7A includes a flat plate-like first press plate 71A and second press plate 72A having a flat surface as a molding surface, and a pressurizing means 73A.
First, the polarizing element body with adhesive sheet 520 is sandwiched between the first press plate 71A and the second press plate 72A.
Then, as shown in FIG. 5, a pressure along the thickness direction of the polarizing element body 52, for example, a pressure of 0.13 kg / m ² is applied between the first press plate 71A and the second press plate 72A by the pressurizing means 73A. Is added. As shown in FIG. 5, the pressurizing means 73A of the present embodiment is a plurality of clip members that sandwich the side edges of the first press plate 71A and the second press plate 72A. The pressing unit 73A applies pressure along the thickness direction between the first press plate 71A and the second press plate 72A by sandwiching the side edges of the first press plate 71A and the second press plate 72A.

  In this way, the polarizing element body 520 with the pressure-sensitive adhesive sheet is sandwiched between the first press plate 71A and the second press plate 72A, and pressure along the thickness direction is applied to the polarizing element body 520 with the pressure-sensitive adhesive sheet by the pressurizing means 73A. Thus, the polarizing element body 52 is set in a flat plate shape and the deformation is restricted.

Next, in process S6, the press die 7A in which the polarizing element body 520 with the adhesive sheet is installed is placed in a thermostat set at a predetermined temperature and heated for a predetermined time, whereby the polarizing element body 520 with the adhesive sheet is heated. Is subjected to heat treatment (S6, polarizing element body heating step). The heat treatment of the polarizing element body 520 with the pressure-sensitive adhesive sheet in this embodiment is preferably performed under heating conditions of a set temperature (heating temperature) of 110 ° C. or higher and 120 ° C. or lower and a heating time of 2 hours or longer.
When the heat treatment is completed, the press die 7A is taken out from the thermostatic bath, and the polarizing element body 520 with an adhesive sheet is taken out from the press die 7A.
The press die 7A has a configuration in which a flat molding surface is brought into contact with both surfaces of the polarizing element body 520 with an adhesive sheet to restrict deformation, and along the thickness direction of the polarizing element body 520 with an adhesive sheet. Any configuration that allows pressurization may be used, and other detailed configurations are not limited.

  Thereafter, in process S7, the release sheet 525 of the adhesive sheet 524 attached to the TAC sheet 522A of the polarizing element body 52 is peeled off, and the translucent substrate 51 is bonded to the TAC sheet 522A via the adhesive sheet 524 (S7). , Translucent substrate bonding step). In this way, the polarizing plate 5 is manufactured.

According to the present embodiment, in the process S6, the polarizing film body 520 and the TAC sheets 522A and 522B of the polarizing element body 52 are contracted in accordance with the heating temperature by performing heat treatment on the polarizing element body 520 with the adhesive sheet. Shrink. In the manufacturing stage of the polarizing plate 5, the polarizing film 521 and the TAC sheets 522 </ b> A and 522 </ b> B are contracted, so that the polarizing plate 5 can be used even if heat, moisture, etc. are generated around the polarizing plate 5 during use. 5 of the polarizing film 521 can be suppressed.
Thus, since the shrinkage | contraction of the polarizing film 521 in use of the polarizing plate 5 can be suppressed, it can suppress that a crack and a big curvature generate | occur | produce in the polarizing element main body 52 by shrinkage | contraction of the polarizing film 521. Therefore, the polarizing plate 5 having high durability and reliability can be manufactured regardless of the use environment.
Moreover, since the curvature which arises in the polarizing element main body 52 can be suppressed, even when the adhesive force of the adhesive sheet 524 is weak, it can suppress that the polarizing element main body 52 peels from the translucent board | substrate 51. FIG.

Furthermore, in this embodiment, in process S6, with respect to the polarizing element main body 520 with an adhesive sheet, the heat processing was performed on the heating conditions of heating temperature 110 degreeC or more and 120 degrees C or less and heating time 2 hours or more.
Here, if heat treatment is performed at a heating temperature lower than 110 ° C., it takes a long heating time to contract the polarizing film 521 to an appropriate contraction amount. On the other hand, when the heat treatment is performed at a heating time higher than 120 ° C., the polarizing film 521 is unlikely to shrink, and the stress dispersion efficiency of the polarizing film 521 decreases.
On the other hand, when the heat treatment is performed at a heating temperature of 110 ° C. or higher and 120 ° C. or lower as in the present embodiment, the polarizing film 521 easily contracts and high stress dispersion efficiency can be obtained. That is, it is possible to manufacture the polarizing element body 52 in which cracking and warping due to the contraction of the polarizing film 521 hardly occur in a relatively short time. Therefore, the polarizing plate 5 with good durability and reliability can be manufactured in a relatively short time.

  Moreover, in process S5, each surface of the polarizing element main body 520 with an adhesive sheet is contact | abutted to each shaping | molding surface of the press plates 71A and 72A, respectively, A deformation | transformation of the polarizing element main body 520 with an adhesive sheet is controlled, Furthermore, adhesive Heat treatment was performed in a state where deformation of the polarizing element body with sheet 520 was restricted. As described above, the heat treatment is performed while bringing the respective surfaces of the polarizing element body 520 with the pressure-sensitive adhesive sheet into contact with the molding surface of the press die 7A, whereby the deformation of the polarizing element body 520 with the pressure-sensitive adhesive sheet can be regulated and the polarizing film 521 is controlled. And the adhesive strength of the TAC sheets 522A and 522B can be increased.

Here, there is a case where warpage has already occurred in the polarizing element body 520 with the adhesive sheet due to environmental factors before the deformation restricting process in the process S5. When the translucent substrate 51 is bonded to the warped polarizing element body 52, bubbles are mixed into the bonding surface, so that the polarizing element body 52 is easily separated from the translucent substrate 51 after the polarizing plate 5 is manufactured.
However, in this embodiment, the polarizing element body 520 with the pressure-sensitive adhesive sheet is shaped into a substantially flat plate by performing heat treatment while restricting deformation of the polarizing element body 520 with the pressure-sensitive adhesive sheet in the processing S5 and the processing S6. Can do. Therefore, in process S7, since the translucent board | substrate 51 can be adhere | attached on the substantially flat polarizing element main body 52, a bubble is hard to mix in an adhesion surface and subsequent peeling can be suppressed.

Here, with respect to the heat treatment in the process S6, the optimum heating conditions for manufacturing a polarizing element body in which cracks hardly occur were confirmed by experiments.
In this experiment, after the heat treatment under a certain heating condition, the progress of the artificial crack in the polarizing element main body was confirmed, and the heating condition in which the artificial crack did not proceed was determined as the optimum heating condition in which the crack hardly occurs.
Table 1 shows the heating conditions employed in this experiment, the number of samples of the polarizing element body heated under each heating condition, and the number of samples in which artificial cracks progressed during aging among the samples heated under each heating condition. Is shown.

As a specific method of this experiment, first, a polarizing element main body is sandwiched between white plate glasses having a thickness of 5 mm, and a 3 kg weight is placed on the white plate glass. Then, the polarizing element body sandwiched between the white plate glasses is heated for a predetermined heating time in a thermostatic chamber set to a predetermined heating temperature. After heating, the polarizing element body is taken out from between the thermostatic chamber and the white plate glass, and a cut (artificial crack) of about 1 mm is made on the edge of the polarizing element body. Further, the polarizing element body is left for a long time (aging) in a thermostatic chamber set at 85 ° C. Then, during aging, it was observed whether or not an artificial crack progresses in the polarizing element body.
In this experiment, Comparative Examples 1 to 3 and Examples 1 to 3 shown in Table 1 were performed while changing the heating conditions. As heating conditions of each example, 85 ° C and 0.5h in Comparative Example 1, 100 ° C and 0.5h in Comparative Example 2, 110 ° C and 0.5h in Comparative Example 3, 110 ° C and 2h in Example 1, In Example 2, the heating conditions of 110 ° C. and 8 hours were employed, and in Example 3, the heating conditions of 110 ° C. and 66 hours were employed.

  From Table 1, it can be seen that in the polarizing element body heated under the heating conditions of Comparative Example 1 and Comparative Example 3, artificial cracks progressed. On the other hand, in the polarizing element main body heated on the heating conditions of the comparative example 2 and Examples 1-3, it turns out that the artificial crack did not advance.

Next, the optimum overheating conditions for manufacturing a polarizing element body in which warpage hardly occurs in the heat treatment of step S6 was confirmed by experiments.
FIG. 6 is a graph showing temporal changes in the heating conditions employed in this experiment and the amount of warpage (mm) during aging of the polarizing element body heated under each heating condition.
Further, in this experiment, a polarizing element body having a long side of 18 mm × short side of 14 mm and a thickness of 0.2 mm was used. Further, as shown in FIG. 7, the amount of warpage of the polarizing element body is the amount of displacement of the other side with respect to one side of the side along the thickness direction of the convex side of the long side of the polarizing element body. .

The specific method of this experiment is almost the same as the artificial crack confirmation experiment described above, and after the heating treatment is performed on the polarizing element body in the thermostatic bath, it is aged in the thermostatic bath set to 85 ° C. And the curvature amount of the polarizing element main body of each example during aging was measured.
In this experiment, Comparative Examples 1 to 3 and Examples 1 to 3 shown in FIG. The heating conditions of each example are 100 ° C. and 0.5 h in Comparative Example 4, 100 ° C. and 2 h in Comparative Example 5, 110 ° C. and 0.5 h in Comparative Example 6, 110 ° C. and 1 h in Comparative Example 7, Examples In No. 4, heating conditions of 110 ° C. and 2 hours were adopted.

As shown in the graph of FIG. 6, it can be seen from Comparative Example 5 and Example 4 that even in the same heating time of 2 h, Example 4 with a higher heating temperature has a smaller amount of warping after aging of the polarizing element body. Furthermore, it can be seen from Comparative Example 7 and Example 4 that, even at the same heating temperature of 110 ° C., the amount of warpage after aging is smaller in Example 4 having a longer heating time.
Further, from Comparative Examples 4 to 7 and Example 4, it can be seen that the amount of warpage tends to decrease as the heating temperature increases, and the amount of warpage after aging tends to decrease as the heating time increases. In the projector, when the projector is turned on, the polarizing element is brought into a high temperature state by the light beam emitted from the light source lamp. The small amount of warping after aging means that the residual stress of the polarizing element is also small when the projector is turned on.

In the above-described artificial crack confirmation experiment (Table 1), the progress of the artificial crack was not confirmed in Comparative Example 2, but in the warpage amount confirmation experiment (FIG. 6), in Comparative Example 4 having the same heating condition as Comparative Example 2. A large amount of warping has occurred. Therefore, it can be determined that the heating conditions of Comparative Example 2 (Comparative Example 4) are not optimal as heating conditions for manufacturing a polarizing element body that is less prone to cracking and warping.
From the above experiments, it can be seen that heating conditions of 110 ° C. and 2 hours or more are optimal for manufacturing a polarizing element body that is less prone to cracking and warping. In this embodiment, since the polarizing element body 520 with the pressure-sensitive adhesive sheet is subjected to the heat treatment at 110 to 120 ° C. for 2 hours or more in the process S6, it is possible to manufacture the polarizing plate 5 that is less likely to crack and warp. confirmed.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the following description, the same structure and the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.
The configuration of the polarizing plate 5A as the polarizing element of the second embodiment is different from that of the first embodiment, and the manufacturing method is also different due to the difference in this configuration.
FIG. 8 is a schematic cross-sectional view along the thickness direction of the polarizing plate 5A of the second embodiment.
The polarizing element body 52A of the polarizing plate 5A of the present embodiment has a TAC sheet only on one surface of the polarizing film 521, as shown in FIG. 8, as compared to the polarizing element body 52 (FIG. 1) of the first embodiment. The difference is that 522B is bonded.

Due to the difference in the configuration of the polarizing element body 52A, the manufacturing method of the polarizing plate 5A is different in the following points compared to the first embodiment.
First, in the protective layer adhesion step of process S2 (FIG. 2), the TAC sheet 522B is adhered to one surface of the polarizing film 521. Furthermore, in the process 3, the adhesive sheet 524 provided with the release paper 525 is attached to the other surface of the polarizing film 521 (the surface to which the TAC sheet 522B is not bonded) to form the polarizing element body 520A with the adhesive sheet. Next, in the deformation regulation process of process S5 and the heating process of process S6, heat treatment is performed on the polarizing element body 520A with an adhesive sheet using a press die 7B as a mold.

FIG. 9 is a schematic cross-sectional view showing a polarizing element body 520A with an adhesive sheet arranged in the press die 7B.
As shown in FIG. 9, the press die 7B includes a first press curved plate 71B having a cylindrical surface as a concave curved molding surface, a second press curved plate 72B having a cylindrical surface as a convex curved molding surface, Pressurizing means 73B.
In the deformation regulation process of process S5, as shown in FIG. 9, the polarizing element body 520A with an adhesive sheet has a cylindrical surface shape in which the polarizing film 521 side is convex by the first press curved plate 71B and the second press curved plate 72B. It is set and pinched. And as shown in FIG. 9, between the 1st press curved plate 71B and the 2nd press curved plate 72B, the pressure along the thickness direction of 52 A of polarizing element bodies by the pressurizing means 73B, for example, 0.13 kg / m < ² >. The pressure of is applied.
In addition, as shown in FIG. 9, the pressurizing means 73B of this embodiment has the same configuration as the pressurizing means 73A (FIG. 5) of the first embodiment.

  In this way, the polarizing element body 520A with the adhesive sheet is sandwiched between the first press curved plate 71B and the second press curved plate 72B, and the pressure along the thickness direction is applied to the polarizing element body 520A with the adhesive sheet by the pressurizing means 73B. Is added to set the polarizing element body 520A with an adhesive sheet in a cylindrical surface shape and regulate the deformation of the polarizing element body 520A with an adhesive sheet.

Next, in the heating step of step S6, the pressing die 7B sandwiching the polarizing element body 520A with an adhesive sheet is left in a constant temperature bath set to a predetermined temperature for a predetermined time, whereby the polarizing element body 520A with an adhesive sheet is placed. Is subjected to heat treatment. Also in this embodiment, it is preferable that the heat treatment of the polarizing element body 520A with the pressure-sensitive adhesive sheet is performed under heating conditions of a heating temperature of 110 ° C. or more and 120 ° C. or less and a heating time of 2 hours or more. When the heat treatment is completed, the press die 7B is taken out from the thermostatic bath, and the polarizing element body 520A with an adhesive sheet is taken out from the press die 7B.
The configuration of the press die 7B is set to a cylindrical surface shape where the polarizing film 521 side is convex by bringing the cylindrical surface into contact with both surfaces of the polarizing element body 520A with the adhesive sheet, and the adhesive sheet. Any structure that can pressurize along the thickness direction of the attached polarizing element body 520 </ b> A may be used, and other detailed structures are not limited.
Finally, in process S7, the translucent substrate 51 is bonded to the polarizing element body 520A with the adhesive sheet via the adhesive sheet 524.

According to the present embodiment, in addition to the functions and effects that can be achieved in the first embodiment, the following effects can be achieved.
Here, when the polarizing element body 520A with the pressure-sensitive adhesive sheet according to the present embodiment is subjected to deformation regulation processing and heat treatment using the press die 7A according to the first embodiment, the polarizing element body 520A with the pressure-sensitive adhesive sheet is Heat treatment is performed in a flat state. In this case, after the heat treatment, when the polarizing element body with adhesive sheet 520A is taken out from the press die 7A, the polarizing element body with adhesive sheet 520A is deformed into a cylindrical surface having a concave on the polarizing film 521 side. This is because the polarizing element main body 520A with the adhesive sheet has the TAC sheet 522B bonded to only one surface of the polarizing film 521, and the polarizing film 521 is more easily contracted than the TAC sheet 522B by heat treatment.

On the other hand, in the present embodiment, the surface of the polarizing film 521A of the polarizing element body 520A with an adhesive sheet is brought into contact with the concave curved surface of the first press curved plate 71B, and the convex curved surface of the second press curved plate 72B. By bringing the TAC sheet 522B surface into contact with the molding surface, the polarizing element main body 520A with an adhesive sheet was previously set in a cylindrical surface shape with the polarizing film 521 side convex, and deformation was restricted.
Then, after the heat treatment in the process S6, when the polarizing element body 520A with an adhesive sheet is taken out from the press die 7B, the shape of the polarizing element body 520A with an adhesive sheet can be deformed into a flat plate shape by using the contraction of the polarizing film 521. it can. Therefore, the flat polarizing element-attached polarizing element body 520A can be manufactured through the processing S5 and the processing S6.

[Modification of the above embodiments]
The best configuration for implementing the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, since each said embodiment does not limit this invention, the description by the name of the member remove | excluding some or all restrictions of those shapes, materials, etc. is included in this invention. It is.

In the present invention, the deformation regulating process (process S5) and the heating process (process S6) are transmitted from the process of bonding the TAC sheets 522A and 522B to the polarizing film 521 of process S2 to the polarizing element bodies 52 and 52A of process S7. As long as it is during the process of bonding the conductive substrate 51, it may be performed anywhere.
In each of the above embodiments, the TAC sheets 522A and 522B made of TAC are used as the protective layer. However, in the present invention, the protective layer has excellent transmittance, heat resistance, and moisture absorption resistance and does not cause birefringence. What is necessary is just to be comprised from the material.
In each of the above embodiments, the polarizing element main bodies 52 and 52A are bonded to the translucent substrate 51 by the adhesive sheet 524 (processing S2). However, in the present invention, they may be bonded by a transparent adhesive.

The press die 7A of the first embodiment may have the following configuration.
In other words, the press die 7A has two heat rollers arranged to face each other at a predetermined interval. The polarizing element body 520 with an adhesive sheet is inserted between the heat rollers, and the adhesive sheet is attached while rotating the heat roller. It is good also as a structure which performs a deformation | transformation control process and a heat processing to the polarizing element main body 520 with an adhesive sheet by pulling out the polarizing element main body 520 slowly. In the modified example, the heat roller may be a roller that does not have a heat generating function. In this case, the heat treatment may be performed on the polarizing element body 520 with the pressure-sensitive adhesive sheet by performing in a temperature-controlled room.

  In each of the embodiments described above, the heat treatment of the polarizing element bodies 520 and 520A with the adhesive sheet is performed on one polarizing element body 520 and 520A with the adhesive sheet. You may give to element body 520,520A at once. For example, the polarizing element bodies with adhesive sheets 520 and 520A may be laminated and subjected to heat treatment, or the polarizing element bodies with adhesive sheets 520 and 520A may be arranged in a plane and subjected to heat treatment.

  INDUSTRIAL APPLICABILITY The present invention can be used for a polarizing element used in an optical device or the like and a manufacturing method of the polarizing element.

1 is a schematic cross-sectional view of a polarizing plate according to a first embodiment of the present invention. The flowchart for demonstrating the manufacturing method of the polarizing plate which concerns on the said embodiment. The schematic cross section which shows the polarizing element main body which concerns on the said embodiment. The schematic cross section which shows the polarizing element main body with an adhesive sheet which concerns on the said embodiment. The figure for demonstrating the heat processing of the polarizing element main body with an adhesive sheet which concerns on the said embodiment. The graph which shows the relationship between the heating conditions of the polarizing element main body which concerns on the said embodiment, and the time change of curvature amount. The figure for demonstrating the measuring method of the curvature amount of the polarizing element main body in the said embodiment. The schematic cross section of the polarizing plate which concerns on 2nd Embodiment of this invention. The figure for demonstrating the heat processing of the polarizing element main body with an adhesive sheet which concerns on the said embodiment.

Explanation of symbols

5, 5A ... Polarizing plate (polarizing element), 51 ... Translucent substrate, 52, 52A ... Polarizing element body, 521 ... PVA film (polarizing film), 522A, 522B ... TAC sheet (protective layer), 7A, 7B ... Press mold (mold).

Claims (4)

A polarizing film that transmits only polarized light in a predetermined direction of the incident light flux, a polarizing element body having a protective layer adhered to at least one surface of the polarizing film, and at least one of the polarizing element bodies A manufacturing method of a polarizing element comprising a translucent substrate bonded to a surface,
A film stretching step for producing a polarizing film by stretching a polyvinyl alcohol-based film containing polyvinyl alcohol as a main component;
A protective layer adhesion step of producing the polarizing element body by adhering the protective layer to at least one surface of the polarizing film produced in the film stretching step;
A deformation regulating step for regulating the deformation of the polarizing element body produced in the protective layer bonding step;
A heating step of heat-treating the polarizing element body, the deformation of which is regulated in the deformation regulation step, under a heating condition of a heating temperature of 110 ° C. or more and 120 ° C. or less and a heating time of 2 hours or more;
A polarizing element comprising: a translucent substrate adhering step of manufacturing the polarizing element by adhering the translucent substrate to at least one surface of the polarizing element body heat-treated in the heating step Manufacturing method. In the manufacturing method of the polarizing element according to claim 1,
The method of manufacturing a polarizing element, wherein the deformation restricting step restricts deformation of the polarizing element body by bringing a molding surface of a mold into contact with both surfaces of the polarizing element body. In the manufacturing method of the polarizing element according to claim 2,
The protective layer bonding step is to manufacture the polarizing element body by bonding the protective layer to any surface of the polarizing film,
In the deformation regulating step, the polarizing element body is curved using the mold in which the molding surface of the polarizing element body that contacts the polarizing film is a concave curved surface and the molding surface that contacts the protective layer is a convex curved surface. A method of manufacturing a polarizing element, wherein the deformation of the polarizing element body is regulated by setting the surface to be planar. A polarizing film that transmits only polarized light in a predetermined direction of the incident light flux, a polarizing element body having a protective layer adhered to at least one surface of the polarizing film, and at least one of the polarizing element bodies A polarizing element comprising a translucent substrate bonded to a surface,
A polarizing element manufactured by the method for manufacturing a polarizing element according to claim 1.

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