JP2010091815A - Method of manufacturing polarizing film, and method of manufacturing polarizing plate using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of enhancing durability of a polarizing film itself from the viewpoint of a specific microstructure while maintaining high optical characteristics. <P>SOLUTION: There is provided a method of manufacturing a polarizing film in which a step of immersion in an aqueous solution containing a crosslinking agent or a hydrophobing agent is carried out at least before a dyeing step in the manufacture of a polarizing film. By using the manufacturing method, crosslinking or hydrophobing of an amorphous region in a polarizing film can be achieved, accordingly a polarizing film having enhanced durability in a hot or hot and humid environment due to regulated local molecular motion can be provided while maintaining high optical characteristics. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a polarizing film. More specifically, the present invention relates to a polarizing film manufacturing method that can be suitably used for a liquid crystal display device, and a polarizing plate manufacturing method using the manufacturing method.

  A liquid crystal display device has a feature of being thin and having low power consumption, and is widely used as a display device for various devices such as a display device for a computer, a mobile phone, and a television receiver. These liquid crystal display devices have a structure in which polarizing plates that transmit only polarized light in a certain direction are arranged on both surfaces of a liquid crystal cell in which liquid crystal is sandwiched between glass substrates or the like.

  This liquid crystal display device has been requested to improve and improve characteristics such as further enlargement, thinning, weight reduction, low power consumption and high contrast in response to customer requests, and various measures have been taken to meet this demand. In order to execute, it is essential to solve the problems associated with each.

  Of these issues, large-scale, thin, and high-contrast designs require a significant change in the design of the backlight unit. In such a case, avoid increasing the thermal load on the liquid crystal panel members. Absent. For this reason, not only is it easily affected by the heat load among liquid crystal panel members, but the durability of the polarizing plate, which is an essential component of the liquid crystal panel and is a key component, in a high-temperature environment and a high-temperature and high-humidity environment is extremely high. It becomes important. In particular, when thin and high performance is to be achieved, it is not possible to avoid the so-called in-cell installation of the optical member in the liquid crystal cell. In such a case, ITO (Indium Tin Oxide) which is a transparent electrode Durability against a thermal load of about a few hundred degrees during film formation is an essential condition.

  By the way, a polarizing plate is conventionally polarized by dyeing a resin film such as polyvinyl alcohol (PVA) with a dichroic dye such as iodine and performing a stretching and fixing process in an aqueous solution containing boric acid or the like. A polarizing plate that imparts performance and has a protective film such as a cellulose-based film such as a TAC (triacetyl cellulose) film laminated on both surfaces of the film is often used because of its superior optical properties.

  In order to reduce the thickness and the like, studies have been made to eliminate a protective film such as a cellulose-based film laminated on the polarizing film. However, in this case, a major problem lies in ensuring durability. In the past, various methods have been proposed to achieve high durability of the polarizing film itself in order to ensure high durability while maintaining the high polarization performance of the polarizing plate.

  As a technique for improving the optical properties of a polarizing film, Patent Document 1 discloses a polyvinyl alcohol polymer having a syndiotacticity of 55% or more and 0.001 to 1% by weight of iodine with respect to the polyvinyl alcohol polymer. A technique for improving optical properties by stretching a film having a thickness of 5 to 150 μm formed by forming a solution containing a uniaxial direction three times or more is disclosed. Patent Document 2 discloses that the standard deviation of the parallel transmittance every 10 nm when the light wavelength is between 420 and 700 nm is 3 or less, and every 10 nm when the light wavelength is between 420 and 700 nm ( A technique for improving optical characteristics by setting the minimum value of parallel transmittance / orthogonal transmittance to 300 or more is disclosed.

  In the technique for improving the optical characteristics of the polarizing film as described above, the type of the crosslinking agent and the timing of applying the crosslinking agent in the polarizing film manufacturing process are arbitrary.

  On the other hand, as a technique for improving the durability of the polarizing film, Patent Document 3 describes a technique of dyeing with an iodine / potassium iodide aqueous solution and stretching in a boric acid aqueous solution, followed by crosslinking and fixing with a glyoxal aqueous solution. A technique for improving durability by applying the above is disclosed. Further, in Patent Document 4, among a series of polarizing film production process steps of swelling, dyeing, fixing, stretching, washing, and drying, a large amount of dialdehyde, dicarboxylic acid, or the like is used in the washing step instead of pure water or iodide aqueous solution. A technique for improving durability by replacing with a functional compound solution and proceeding with crosslinking is disclosed. These methods are generally easy to imagine if the intermolecular distance is widened to some extent as in polymer solutions and the cross-linker reagent is likely to attack the functional group of the substrate. The effect is not different from the expectation.

  However, when the PVA film produced by using the technique of Patent Document 3 was subjected to a viscoelasticity test for high temperature humidification assuming storage under high temperature and high humidity and a warming viscoelasticity test assuming high temperature storage, It was found that dimensional shrinkage was not improved. In addition, when a follow-up test was conducted with a single PVA film manufactured using the technique of Patent Document 4, it was found that the dipping time was long and the problem of increased Haze or the durability deteriorated conversely with the single PVA film. It was. Therefore, even when the techniques of Patent Document 3 and Patent Document 4 are used, it has been clarified that when the polarizing plate is thinned without a protective film such as a TAC film, the durability improvement effect cannot be expected. .

  Thus, unlike the polymer solution, in the case of the PVA film, it is not clear why the intermolecular distance is narrow, but the durability is improved only by adding a simple cross-linking agent. It is not easy to make a forecast or forecast.

  In addition, the techniques of Patent Document 3 and Patent Document 4 are also a result derived in a coping therapy, and are not currently studied because a solution is not derived by assuming a specific microstructure. In the case of reducing the thickness by removing a protective film such as a TAC film while maintaining high optical properties, it is not only possible to satisfy the durability in a high temperature and high temperature and high humidity environment, but also to find a fundamental solution. Has not reached.

  Here, as a prior art assuming a specific microstructure, in Non-Patent Document 1 below, it is estimated that boric acid breaks the crystal region of PVA and forms a crosslinked structure via a new hydrogen bond. The inventors of the present application have also studied and analyzed using X-ray diffraction (XRD), and boric acid penetrates into the PVA crystal region to refine the crystal phase, and when drawn, the amorphous region decreases and the crystal region expands. Confirmed to do. FIG. 10 shows the XRD measurement results when the process in the polarizing film manufacturing process is changed, and FIG. 11 shows the XRD measurement results for each process in the polarizing film manufacturing process. Specific measurement conditions are as follows: XRD apparatus: JOEL JDX-3500 (manufactured by JEOL Ltd.), X-ray source: Cu, 40 kV, 300 mA, step width: 0.02 °, scanning range: 3 ° -60 ° Measurement time: 0.5 sec.

  As shown in (iii) and (iv) of FIG. 10, it is clear that the main diffraction peak is broadened (the crystal region is refined and the crystal lattice spacing is not uniform) due to boric acid rather than iodine. It became. In addition, as shown in FIGS. 10 (i) and (ii), in the absence of boric acid, the intensity of the main diffraction peak becomes steep due to stretching (the crystal region increases without changing the crystal lattice spacing). found.

  Further, from the results of FIG. 10 and FIG. 11, it was inferred that the microstructure in the film was changed as shown in FIG. As shown in FIG. 12B, in the stretched state, the crystalline phase grows (main diffraction intensity increases) by stretching, the molecular chain rotates inside the crystal, the crystal planes are aligned, and the crystalline phase is partially May also occur. In addition, as shown in FIG. 12C, in the dyed stretch crosslinked state, it is considered that boric acid enters the crystal phase and the crystal phase becomes smaller, and the crystal lattice spacing is irregularly disturbed.

JP-A-8-190017 JP 2002-221618 A JP-A-6-235815 JP 2006-139166 A 15th Polymer Materials Forum Proceedings, 126 (2006)

  As described above, various methods have been proposed as a method for improving the durability of the polarizing film, but since it is not a study for deriving a solution assuming a specific microstructure, Therefore, new technology for improving durability is expected.

  Therefore, the main object of the present invention is to provide a technique that can increase the durability of the polarizing film itself from the viewpoint of a specific microstructure while maintaining high optical characteristics.

  The inventors of the present application have conducted intensive studies to develop a method capable of producing a polarizing film that ensures higher durability while maintaining high optical properties of high transmittance and high degree of polarization. For example, a small cross-linkable agent such as boric acid is put in the region, and the intermolecular distance is reduced to some extent by performing a stretching operation to increase the intermolecular orientation. The model of the microstructure was derived by introducing local and hydrophobic groups to regulate local molecular motion and to improve the durability under high temperature and high temperature and high humidity environment.

  Based on this microstructure model, the conventional series of manufacturing processes such as swelling, dyeing, stretching, fixing, and drying of polarizing films are immersed in a predetermined aqueous solution at an insane timing. As a result, it was confirmed that a highly durable polarizing film was obtained, and the present invention was achieved.

That is, in the present invention, first, at least before the dyeing step in the production of the polarizing film,
Provided is a method for producing a polarizing film, comprising at least a step of immersing the film in an aqueous solution containing a crosslinking agent or a hydrophobizing agent.
Conventionally, it is common knowledge that if crosslinking or hydrophobing is performed before dyeing, dyeing is not sufficiently performed, and if cross-linking or hydrophobizing is performed before stretching, it is difficult to stretch. Met. However, in the present invention, it is possible to realize cross-linking or hydrophobization of the amorphous region in the polarizing film by performing a cross-linking treatment or a hydrophobizing treatment before dyeing and stretching.
As long as the film which can use the manufacturing method which concerns on this invention is a film which consists of a raw material which can be used for a polarizing film, the kind will not be specifically limited, From a viewpoint of an optical characteristic, a polyvinyl-alcohol-type film is preferable.
The pH of the solution containing the crosslinking agent or hydrophobizing agent is not particularly limited as long as the object of the present invention is not impaired, but is preferably 0 or more and 4 or less.
The kind of the crosslinking agent that can be used in the method for producing a polarizing film according to the present invention is usually a crosslinking having a size that can easily enter an amorphous region in which the polymer chain length is widened through a swelling process. If it is an agent, the kind will not be specifically limited, However, As an example, a polyvalent aldehyde can be used conveniently.
Examples of the polyvalent aldehyde in this case include glyoxal or glutaraldehyde.
The kind of the hydrophobizing agent that can be used in the method for producing a polarizing film according to the present invention is usually large enough to easily enter an amorphous region in which the polymer chain length is widened through a swelling process. Although the kind will not be specifically limited if it is a hydrophobizing agent, As an example, a monoaldehyde can be used conveniently.
Examples of the monoaldehyde in this case include formaldehyde or acetaldehyde.
The manufacturing method of the polarizing film which concerns on this invention can be used suitably also for manufacture of a polarizing plate by performing as one process of the manufacturing process of a polarizing plate.

  By using the method for producing a polarizing film according to the present invention, it is possible to achieve cross-linking or hydrophobization of the amorphous region in the polarizing film. It is possible to provide a polarizing film having improved durability in a humid environment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly.

<Production method of polarizing film>
FIG. 1 is a flowchart showing an example of a method for producing a polarizing film according to the present invention. In the method for producing a polarizing film according to the present invention, at least a step of immersing in a predetermined aqueous solution (hereinafter referred to as “aqueous solution immersing step A”) is performed before the dyeing step performed by a normal method for producing a polarizing film. It is characterized by.

  If the film which can be used for the manufacturing method which concerns on this invention is a film which consists of a raw material which can be used for a polarizing film, the kind will not be specifically limited, The film which consists of all raw materials can be selected freely and used. Can do. Moreover, the thickness is not specifically limited, The film about 50-150 micrometers similar to a normal film can be used.

  Especially in this invention, a polyvinyl alcohol-type film can be used suitably from a viewpoint of heat resistance or an optical characteristic. Examples of the polyvinyl alcohol-based resin film include a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, a poly (ethylene-vinyl acetate) copolymer film, a partially saponified film or a completely saponified film thereof, and a partially polyene of polyvinyl alcohol. And the like. When a copolymer film is used, the degree of polymerization is not particularly limited, but the degree of polymerization is preferably in the range of 1500 to 3000 in order to obtain high optical properties. In the case of using a partially saponified film or a completely saponified film, the degree of saponification is not particularly limited, but in order to obtain high optical properties, the range of the degree of saponification is desirably 98 to 100 mol%.

(A) Aqueous solution immersion step The aqueous solution immersion step A is a step in which the film is immersed in an aqueous solution containing a crosslinking agent or a hydrophobizing agent, and the inside of the film is subjected to a crosslinking treatment or a hydrophobic treatment.
Conventionally, crosslinking or hydrophobic treatment has not been performed before dyeing because dyeing is not sufficiently performed. Moreover, the crosslinking treatment or the hydrophobizing treatment was not performed before the stretching because the stretching becomes difficult. However, in the present invention, high durability was achieved while maintaining optical properties by carrying out a crosslinking treatment or a hydrophobic treatment before dyeing and stretching. Even if the aqueous solution dipping step A is performed after dyeing / stretching, it is difficult to contain only a small cross-linking agent such as boric acid in the stretched film. Is not expected.

  The kind of the crosslinking agent that can be used in the aqueous solution immersion step A is not particularly limited, and any known crosslinking agent can be freely selected and used as long as the inside of the film can be crosslinked. As an example, a polyvalent aldehyde can be used. In this case, although the kind of polyvalent aldehyde is not limited, for example, glyoxal or glutaraldehyde can be mentioned.

  The type of the hydrophobizing agent that can be used in the aqueous solution immersion step A is not particularly limited, and one or more known hydrophobizing agents can be freely selected and used as long as the inside of the film can be hydrophobized. Can do. As an example, monoaldehyde can be used. In this case, the type of monoaldehyde is not limited, but examples include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, methylglyoxal, and the like.

  The pH in the treatment bath for performing the immersion treatment is not particularly limited as long as the crosslinking treatment or the hydrophobization treatment can be performed, but in the present invention, the pH is preferably from 0 to 4 inclusive. If the pH is less than 0, the reaction may proceed too much, causing problems such as a rapid increase in the haze (cloudiness) of the polymer film or film breakage. Conversely, if the pH exceeds 4, the reaction will occur. This is because the expected effect may not occur and the pH adjustment with an acid may be difficult, and the film may dissolve during immersion.

  Further, the concentration and temperature of the aqueous solution for the immersion treatment are not particularly limited as long as the crosslinking treatment or the hydrophobization treatment can be performed, but in the present invention, the concentration is preferably in the range of 0.2 wt% to 20 wt%. The temperature is preferably in the range of 20 ° C to 60 ° C.

  As described above, in the production method according to the present invention, the aqueous solution immersion treatment step A is performed before dyeing / stretching, so that it is difficult to crosslink or hydrophobize an amorphous region, which is difficult to crosslink or hydrophobize in the conventional production method. Can be realized. Therefore, it is possible to remarkably improve the durability under a high temperature or high temperature and humidity environment by regulating local molecular motion while maintaining the high optical properties of the polarizing film.

  Although the manufacturing method of the polarizing film which concerns on this invention includes all the methods which perform the aqueous solution immersion process A demonstrated above as one process at least before a dyeing process, for example, as shown in FIG. 1, a normal manufacturing process is included. (1) Swelling process I, (2) Dyeing process II, (3) Stretching process III, (4) Cross-linking immobilization process IV, (5) Drying process V, etc. can be appropriately performed. Hereinafter, each process will be described with an example.

(1) Swelling process I
The swelling process I is a process of swelling the film as a pretreatment of the stretching process III described later. The solvent used for the swelling is not particularly limited, and a solvent used in a swelling process in a normal method for producing a polarizing film can be freely selected and used. For example, pure water, potassium iodide aqueous solution, etc. can be mentioned. In the present invention, it is preferable to use pure water from the viewpoint of ease of swelling. The liquid temperature of the swelling bath is not particularly limited and can be set freely according to the thickness of the film and the type of solvent. In the present invention, it is preferably 20 ° C. or higher and 45 ° C. or lower.

(2) Dyeing process II
In the dyeing process II, the film is dyed by immersing the film in an aqueous dye solution. The dye used for dyeing is not particularly limited as long as it is a dichroic substance, and a dye used in a dyeing process in a normal method for producing a polarizing film can be freely selected and used. For example, iodine, red R, etc. can be mentioned. In the present invention, it is particularly preferable to use an iodine system. When iodine is used, it is preferable to use a mixed aqueous solution of iodine, potassium iodide, and boric acid as a specific dyeing aqueous solution. The weight concentrations of iodine, potassium iodide, and boric acid are 0.015 wt% to 0.025 wt%, 1.5 wt% to 4.0 wt%, and 1.0 wt% to 3.0 wt%, respectively. It is preferable that it is the range of these. Moreover, the temperature of the dyeing aqueous solution, the immersion time, etc. can be freely set according to the type and form of the polarizing film, the relationship with other processes, and the like. Particularly preferable conditions in the present invention are about 25 ° C. or more and 35 ° C. or less for the temperature of the dyeing aqueous solution.

(3) Drawing process III
In the stretching process III, stretching is performed at a magnification according to the purpose in order to impart polarization characteristics. The stretch ratio is not particularly limited and can be set freely according to the desired polarization characteristics. However, in the present invention, the stretch ratio is preferably several times that of the film before swelling.

  In the stretching process III in the present invention, any method such as wet stretching or dry stretching can be used freely, but in the present invention, wet stretching is preferable. When performing wet stretching, the aqueous solution of the stretching bath is not particularly limited, and an aqueous solution used in a stretching process in a normal method for producing a polarizing film can be freely selected and used. For example, a mixed aqueous solution composed of potassium iodide and boric acid can be used. In this case, the concentrations of potassium iodide and boric acid are not particularly limited, and can be appropriately set as necessary, but potassium iodide is 2.0 wt% to 4.0 wt%, boric acid is 2.5 wt%. It is preferable to set in the range of ˜4.0 wt%. Further, the temperature of the aqueous solution of the stretching bath can be freely set according to the type and form of the polarizing film, the relationship with other processes, etc., but in the present invention, it is 45 ° C. or more and 60 ° C. It is preferable to set the following.

(4) Crosslinking immobilization process IV
In the cross-linking and fixing process IV, the film that has been stretched at a predetermined magnification in the stretching process III is dipped in a cross-linking and fixing bath to be cross-linked and fixed. The aqueous solution of the cross-linking immobilization bath is not particularly limited, and an aqueous solution used in the cross-linking immobilization process in a normal method for producing a polarizing film can be freely selected and used. For example, a mixed aqueous solution composed of potassium iodide, boric acid, and zinc chloride can be used. In this case, the concentrations of potassium iodide, boric acid, and zinc chloride are not particularly limited, and can be appropriately set as necessary. In the present invention, potassium iodide is set in the range of 2.0 wt% to 4.0 wt%, boric acid is set in the range of 1.0 wt% to 4.0 wt%, and zinc chloride is set in the range of 1.0 wt% to 2.0 wt%. Is preferred. Further, the temperature of the aqueous solution of the cross-linking and fixing bath can be freely set in accordance with the type and form of the polarizing film, the relationship with other processes, etc. In the present invention, it is 30 ° C. or higher. It is preferable to set to 45 ° C. or lower.

(5) Drying process V
The drying process V is a process of drying the polarizing film fixed in the cross-linking and fixing process IV. The drying temperature and drying time in the drying process V can be freely set according to the type and form of the polarizing film, the relationship with other processes, and the like. From the viewpoint of the ability to remove water contained in the polarizing film and the viewpoint of drying efficiency, it is preferable to perform drying at 85 ° C. or higher and 120 ° C. or lower. However, suddenly drying at a high temperature changes the iodine complex ion distribution, so that the hue of the polarizing film is greatly deviated. In the present invention, it is preferable to go through a drying process in which the temperature rises stepwise.

<Production method of polarizing plate>
The manufacturing method of the polarizing film which concerns on this invention can be used suitably for manufacture of a polarizing plate by performing as one process at the time of manufacture of a polarizing plate. For example, a polarizing film is produced by the method for producing the polarizing film, and a hard coat layer, an antireflection layer, an ultraviolet absorption layer, an antiglare layer, an antireflection layer, a half reflection layer, a reflective layer are formed on the polarizing film as necessary. Then, functional layers such as a phosphorescent layer, a diffusion layer, an electroluminescence layer, a viewing angle expansion layer, and a brightness enhancement layer are bonded together using a known adhesive, and then polarized by solidifying the adhesive with an electron beam or the like. A board can be manufactured.

  In addition, since the polarizing film manufactured by the method for manufacturing a polarizing film according to the present invention has extremely high durability, the protective film does not need to be laminated like a conventional polarizing film. In order to further improve the properties, it is possible to produce a polarizing plate by laminating an optically isotropic protective film on one or both sides of the polarizing film in addition to the functional layer.

  When laminating a protective film, the kind is not particularly limited, and a protective film made of any known material can be freely selected and used. For example, mention may be made of protective films made of triacetyl cellulose, diacetyl cellulose, polycarbonate, polymethyl methacrylate, polystyrene, polyether sulfone, polyarylene ester, poly-4-methylpentene, polyphenylene oxide, cyclo or norbornene polyolefin. it can.

<Liquid crystal display device / color liquid crystal display device>
Since the polarizing film manufactured using the manufacturing method according to the present invention has significantly higher heat resistance and moisture resistance than conventional polarizing films, it can be suitably used as a member of a liquid crystal display device. Hereinafter, an example of a liquid crystal display device that can use a polarizing film manufactured using the manufacturing method according to the present invention will be described with reference to the drawings.

  FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an example of a liquid crystal display device 1 that can use a polarizing film manufactured by the manufacturing method according to the present invention. The liquid crystal display device 1 is roughly classified into a liquid crystal panel 10 including a pair of substrates 13 and a liquid crystal layer 14 sandwiched between the substrates 13, and a light source 20 for irradiating the liquid crystal panel 10 with light. And consist of

  The liquid crystal panel 10 of the liquid crystal display device 1 includes a polarizing film 11 manufactured by using the manufacturing method according to the present invention described above. The arrangement location of the polarizing film 11 in the liquid crystal panel 10 is not particularly limited as long as the polarizing film 11 is arranged as an incident side polarizing film and an outgoing side polarizing film with at least the liquid crystal layer 14 interposed therebetween, and conforms to the arrangement of the polarizing film in a normal liquid crystal display device. Can be designed freely.

  Each substrate 13 has an electrode 12 disposed on its inner surface. Further, if necessary, an alignment film 15 for arranging liquid crystal molecules in a certain direction between the electrode 12 and the liquid crystal layer 14, a color between the electrode 12 and the substrate 13, or a color between the substrate 13 and the polarizing film 11. Members used in a normal liquid crystal display device such as a color filter 16 for display can be freely selected and used.

  The specific configuration of the liquid crystal layer 14 is not particularly limited, and can be freely designed according to the structure used in a normal liquid crystal display device. For example, as shown in FIG. 2, a configuration in which a liquid crystal material is injected between a pair of substrates 13 opposed to each other at a predetermined interval by a spacer 17 can be exemplified. The spacer 17 is for holding a predetermined distance between the pair of substrates 13.

  As the substrate 13, the electrode 12, the liquid crystal layer 14, the alignment film 15, and the like, those used in a normal liquid crystal display device can be freely selected and used.

  FIG. 3 is a schematic cross-sectional view showing a schematic configuration of an example of a color liquid crystal display device 100 in which a polarizing film manufactured using the manufacturing method according to the present invention can be used. The color liquid crystal display device 100 is roughly divided into (a-1) a pair of substrates 13 and (a-2) a liquid crystal layer 14 sandwiched between the substrates 13, and includes first to third pixels. A set of pixels includes a plurality of color liquid crystal panels 10 arranged in a two-dimensional matrix, and a light source 20 for irradiating the color liquid crystal panel 10 with light.

  Like the liquid crystal display device 1 shown in FIG. 2, the liquid crystal panel 10 of the color liquid crystal display device 100 includes a polarizing film 11 manufactured by using the manufacturing method according to the present invention. The arrangement location of the polarizing film 11 in the liquid crystal panel 10 is not particularly limited as long as the polarizing film 11 is arranged as an incident side polarizing film and an outgoing side polarizing film with at least the liquid crystal layer 14 interposed therebetween, and conforms to the arrangement of the polarizing film in a normal liquid crystal display device. Can be designed freely. For the substrate 13, the electrode 12, the liquid crystal layer 14, the alignment film 15, etc., those used in a normal liquid crystal display device can be freely selected and used as in the liquid crystal display device 1 shown in FIG. 2. be able to.

  The light source 20 of the color liquid crystal display device 100 emits first primary color light corresponding to the first primary color among the three primary colors composed of the first primary color, the second primary color, and the third primary color. For example, the first primary color light is configured as blue light (for example, a wavelength λ1: any wavelength within the range of 440 nm to 460 nm), the second primary color is configured as green light, and the third primary color is configured as red light. be able to. The colors of the first to third primary colors are not limited to this, and the first primary color, the second primary color, and the third primary color may be red, green, and blue, respectively, if necessary. The first primary color, the second primary color, and the third primary color may be green, red, and blue, respectively. The specific device of the light source 20 is not limited as long as it can emit any first primary color light, and a known light source can be freely selected and used.

  The color liquid crystal panel 10 of the color liquid crystal display device 100 includes (1) a second primary color light emitting region 102 and (2) a third primary color light emitting region 103 in addition to the polarizing film 11 manufactured using the manufacturing method according to the present invention. (3) A diffusion or passage region is provided at least. Hereinafter, each region will be described.

(1) Second primary color light emitting region 102
The second primary color light emitting region 102 is a region formed of second primary color light emitting particles that are arranged on the same optical path as the second pixels of the color liquid crystal panel 10 and emit second primary color light corresponding to the second primary color. In the second primary color light emitting region 102, the second primary color light emitting particles constituting the second primary color light emitting region 102 are excited by the first primary color light emitted from the light source 20 to emit second primary color light.

The second primary color luminescent particles are not particularly limited as long as they are particles that can be excited by the first primary color light emitted from the light source 20 to emit the second primary color light. Any known luminescent particles can be freely used. It can be selected and used. For example, when the second primary color light emitting particles are phosphor particles that emit green light, (ME: Eu) Ga ₂ S ₄ , (M: RE) x (Si, Al) ₁₂ ( O, N) ₁₆ , (M: Tb) x (Si, Al) ₁₂ (O, N) ₁₆ , (M: Yb) x (Si, Al) ₁₂ (O, N) ₁₆ , LaPO ₄ : Ce, Tb BaMgAl ₁₀ O ₁₇ : Eu, Mn, Zn ₂ SiO ₄ : Mn, MgAl ₁₁ O ₁₉ : Ce, Tb, Y ₂ SiO ₅ : Ce, Tb, MgAl ₁₁ O ₁₉ : CE, Tb, Mn, (Sr, Ba ) ₂ SiO ₄ : Eu. Here, “ME” means at least one atom selected from the group consisting of Ca, Sr and Ba, and “M” means at least one type selected from the group consisting of Li, Mg and Ca. It means an atom, and “RE” means Tb and Yb (the same applies hereinafter).

(2) Third primary color light emitting region 103
The third primary color light emitting region 103 is a region composed of third primary color light emitting particles that are arranged on the same optical path as the third pixel of the color liquid crystal panel 10 and emit the third primary color light corresponding to the third primary color. In the third primary color light emitting region 103, the third primary color light emitting particles constituting the third primary color light emitting region 103 are excited by the first primary color light emitted from the light source 20 to emit the third primary color light.

The third primary color luminescent particles are not particularly limited as long as they are particles that can be excited by the first primary color light emitted from the light source 20 to emit the third primary color light, and any known luminescent particles can be freely used. It can be selected and used. For example, when the third primary color light emitting particles are phosphor particles that emit red light, (ME: Eu) S, (M: Sm) x (Si, Al) ₁₂ (O, N) are used as the red light emitting phosphors. ₁₆ , ME ₂ Si ₅ N ₈ : Eu, (Ca: Eu) SiN ₂ , (Ca: Eu) AlSiN ₃ , Y ₂ O ₃ : Eu, YVO ₄ : Eu, Y (P, V) O ₄ : Eu 3.5 MgO.0.5 MgF ₂ .Ge ₂ : Mn, CaSiO ₃ : Pb, Mn, Mg ₆ AsO ₁₁ : Mn, (Sr, Mg) ₃ (PO ₄ ) ₃ : Sn, La ₂ O ₂ S: Eu , Y ₂ O ₂ S: Eu.

The second primary color light emitting region 102 and the third primary color light emitting region 103 may emit cyan, and in this case, green light emitting phosphor particles (for example, LaPO ₄ : Ce, Tb, BaMgAl ₁₀ O). ₁₇ : Eu, Mn, Zn ₂ SiO ₄ : Mn, MgAl ₁₁ O ₁₉ : Ce, Tb, Y ₂ SiO ₅ : Ce, Tb, MgAl ₁₁ O ₁₉ : CE, Tb, Mn) and blue light emitting phosphor particles (for example, BaMgAl ₁₀ O ₁₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Sr ₂ P ₂ O ₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, (Sr, Ca, Ba, Mg) ₅ (PO ₄ ) ₃ Cl: Eu, CaWO ₄ , CaWO ₄ : Pb) may be used.

  The second primary color light emitting region 102 and the third primary color light emitting region 103 made of phosphor particles use a phosphor particle composition prepared from phosphor particles. For example, a red photosensitive phosphor particle composition (red A light emitting phosphor slurry) is applied to the entire surface, exposed and developed to form a third primary color light emitting region 103 composed of a red light emitting phosphor layer, and then a green photosensitive phosphor particle composition (green light emitting fluorescence). Body slurry) is applied to the entire surface, exposed and developed to form a second primary color light emitting region 102 composed of a green light emitting phosphor layer. Note that the order of the formation of the third primary color light emission region 103 and the formation of the second primary color light emission region 102 may be reversed. Alternatively, the third primary color light emitting region 103 and the second primary color light emitting region 102 may be formed by sequentially applying a red light emitting phosphor slurry and a green light emitting phosphor slurry, and then sequentially exposing and developing each phosphor slurry. Then, the second primary color light emitting region 102 and the third primary color light emitting region 103 may be formed by a screen printing method, an ink jet printing method, a float coating method, a sedimentation coating method, a phosphor film transfer method, or the like.

  In addition, the material constituting the second primary color light emitting region 102 and the third primary color light emitting region 103 is not limited to the light emitting fluorescent particles. For example, in the indirect transition type silicon-based material, carriers are efficiently used as in the direct transition type. Quantities such as a two-dimensional quantum well structure, a one-dimensional quantum well structure (quantum wire), and a zero-dimensional quantum well structure (quantum dot) using the quantum effect to localize the wave function of the carrier in order to convert light well There can also be mentioned luminescent particles to which a well structure is applied. In addition, it is known that rare earth atoms added to semiconductor materials emit light sharply due to intra-shell transition, and light emitting particles to which such a technique is applied can also be mentioned.

  If the second primary color emission region 102 and the third primary color emission region 103 are arranged on the same optical path as the second subpixel and the third subpixel, respectively, they are arranged on the incident side or the emission side with the liquid crystal layer 14 interposed therebetween. May be.

  When the second primary color emission region 102 and the third primary color emission region 103 are arranged on the emission side from the liquid crystal layer 14, although not shown, the second primary color emission region 102, the third primary color emission region 103 and the emission side electrode 12 are not shown. In the meantime, a second condensing member that condenses the first primary color light to the second primary color light emitting region 102 and a third condensing member that condenses the first primary color light to the third primary color light emitting region 103 are further provided. It is desirable to provide. This is because the occurrence of parallax and the occurrence of optical crosstalk can be surely prevented by these second and third light collecting members. In this case, the second condensing member and the third condensing member may be configured by integrating a lens array, a lenticular lens, or a microlens array in which a large number of gradient index lenses are arranged.

  On the other hand, when the second primary color light emitting region 102 and the third primary color light emitting region 103 are arranged on the incident side from the liquid crystal layer 14, the second primary color light emitting region 102, the third primary color light emitting region 103 and the incident side electrode 12 are not shown. Between the second primary color light emitted from the second primary color light emitting region 102 and the second light collecting member for condensing the second primary color light emitted to the second subpixel, and the third primary color emitted from the third primary color light emitting region 103 It is desirable to further include a third condensing member that condenses the light onto the third subpixel. This is because the occurrence of parallax and the occurrence of optical crosstalk can be surely prevented by these second and third light collecting members.

(3) Diffusion or Passing Area The diffusion or passing area 101 is an area that is arranged on the same optical path as the first subpixel and diffuses or passes the first primary color light emitted from the light source 20. This region becomes a diffusion region (reference numeral 101 in FIG. 3) for diffusing the first primary color light when arranged on the emission side from the liquid crystal layer 14, and passes the first primary color light when arranged on the incident side from the liquid crystal layer 14. This is a passing region (not shown).

  The configuration of the diffusion region 101 is not particularly limited as long as the first primary color light emitted from the light source 20 can be diffused. For example, a light diffusing agent composed of fine particles is dispersed in a transparent binder resin. It can be formed by various coating methods such as a screen printing method and an ink jet printing method. The light diffusing agent is a particle having a property of diffusing light from the light source 20, and can be composed of inorganic material particles or organic material particles. Specific examples of the inorganic material constituting the inorganic material particles include silica, aluminum hydroxide, aluminum oxide, titanium oxide, zinc oxide, barium sulfate, magnesium silicate, and a mixture thereof. On the other hand, as resins constituting organic material particles, acrylic resins, acrylonitrile resins, polyurethane resins, polyvinyl chloride resins, polystyrene resins, polyacrylonitrile resins, polyamide resins, polysiloxane resins, melamine resins Can be illustrated. Examples of the shape of the light diffusing agent include a spherical shape, a cubic shape, a needle shape, a rod shape, a spindle shape, a plate shape, a scale shape, and a fiber shape.

  In addition, you may comprise the diffusion area | region 101 from a light-diffusion sheet (light-diffusion film).

  Although not shown, it is desirable to further include a first light collecting member that collects the first primary color light to the diffusion region 101 between the diffusion region 101 and the emission-side electrode 12. This is because the first light collecting member can surely prevent the occurrence of parallax and the occurrence of optical crosstalk. In this case, the first condensing member can be configured by integrating a lens array, a lenticular lens, or a microlens array in which a large number of gradient index lenses are arranged.

  It is desirable to further include a first light collecting member that condenses the first primary color light that has passed through the passage area onto the first subpixel, between the passage area and the incident-side electrode 12. This is because the first light collecting member can surely prevent the occurrence of parallax and the occurrence of optical crosstalk.

  In the color liquid crystal display device 100, a region between the second primary color light emission region 102 and the third primary color light emission region 103, a region between the diffusion or passage region and the second primary color light emission region 102, a diffusion or passage region and the third region. A light absorption layer 104 (so-called black matrix) can be formed in a region between the primary color light emitting regions 103. As a material constituting the light absorption layer 104, it is preferable to select a material that absorbs 99% or more of the first primary color light, the second primary color light, and the third primary color light. For example, materials such as carbon, a metal thin film, a heat resistant organic resin, and a glass paste can be given, and specific examples include a photosensitive polyimide resin, chromium oxide, and a chromium oxide / chromium laminated film. The light absorption layer 104 can be used as a material to be used, for example, a vacuum deposition method, a combination of a sputtering method and an etching method, a vacuum deposition method, a sputtering method, a combination of a spin coating method and a lift-off method, a screen printing method, a lithography technique, or the like. It can be formed by a method appropriately selected depending on the method.

  The light reflecting film 18 that transmits the first primary color light and reflects the second primary color light and the third primary color light on the light source 20 side of the second primary color light emission region 102, the third primary color light emission region 103, and the diffusion or passage region. Is preferably arranged. By arranging the light reflecting film that reflects the second primary color light and the third primary color light, the second primary color light and the third primary color light emitted in the second primary color light emission region and the third primary color light emission region are changed to the second sub-color light. The pixel and the third sub-pixel are not invaded, and the second primary color light and the third primary color light are efficiently emitted from the second primary color light emission region and the third primary color light emission region, and a bright and clear image can be obtained.

  When the light reflection film 18 is disposed in the color liquid crystal display device 100, the light reflection film 18 is not particularly limited as long as it transmits the first primary color light and reflects the second primary color light and the third primary color light. It can be freely selected and used. For example, it can be composed of a silicon oxide film, a niobium oxide film, a multilayer laminated film composed of a low refractive index material and a high refractive index material (for example, a multilayer laminated film composed of a silicon oxide film and a niobium oxide film), for example, They can be formed by physical vapor deposition methods such as various coating methods and sputtering methods. Moreover, you may arrange | position by laminating | stacking a film-form light reflection film.

  Further, the smoothing film 19 is laminated on the second primary color light emitting region 102, the third primary color light emitting region 103, the diffusion or passage region, the first light collecting member, the second light collecting member, and the third light collecting member. It is preferable that they are arranged. By disposing the smoothing film 19, the second primary color light emitting region 102, the third primary color light emitting region 103, and the diffusion or passage region, the first light collecting member, the second light collecting member, and the third light collecting member are arranged. Differences in surface irregularities and thickness can be absorbed, and a bright and clear image can be obtained more effectively.

  When the smoothing film 19 is disposed in the color liquid crystal display device 100, the type thereof is not particularly limited, and a known smoothing film can be freely selected and used. For example, it can be composed of an acrylic resin or a silicone resin, and can be formed by various coating methods, for example. Moreover, you may arrange | position by laminating | stacking a film-like smoothing film | membrane.

  In the color liquid crystal display device 100, the size of the diffusion or passage region and the size of the portion through which the first sub-pixel actually transmits light may be the same size, the former may be larger, or the latter. May be large. Further, the outer shape of the diffusion or passage region and the outer shape of the portion through which the first sub-pixel actually transmits light may be the same shape, may be similar shapes, or may be different shapes. Also good.

  Similarly, the size of the second primary color light emitting region 102 and the size of the portion through which the second subpixel actually transmits light may be the same size, the former may be large, or the latter may be large. May be. In addition, the outer shape of the second primary color light emitting region 102 and the outer shape of the portion through which the second subpixel actually transmits light may be the same shape, a similar shape, or a different shape. There may be.

  Similarly, the size of the third primary color light emitting region 103 and the size of the portion through which the third sub-pixel actually transmits light may be the same size, the former may be large, or the latter may be large. May be. In addition, the outer shape of the third primary color light emitting region 103 and the outer shape of the portion through which the third sub-pixel actually transmits light may be the same shape, similar shapes, or different shapes. There may be.

  In the color liquid crystal display device 100, one pixel may include at least a first subpixel, a second subpixel, and a third subpixel, and further includes a fourth subpixel, a fifth subpixel, and so on. You may have. The colors to be displayed by the fourth sub-pixel, the fifth sub-pixel,... May be determined based on specifications required for the color liquid crystal display device 100. For example, white for improving luminance, color reproduction range For example, yellow, cyan, and magenta can be exemplified to increase the complementary color for enlarging the color and the color reproduction range.

  In this case, the i-th light emitting region (i = 4, 5,...) Is disposed on the same optical path as the i-th subpixel, and emits light corresponding to the i-th color. And is an area that emits light corresponding to the i-th color when excited by the first primary color light emitted from the light source 20.

  Note that the arrangement state of the sub-pixels of the color liquid crystal display device 100 is not particularly limited, and can be freely designed according to a normal liquid crystal display device. For example, a delta arrangement, a stripe arrangement, a diagonal arrangement, and a rectangle arrangement can be exemplified.

  The color liquid crystal display device 100 described above can perform color display without using a color filter, but a color filter may be disposed in order to further improve the color purity of an image.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, the Example demonstrated below shows an example of the typical Example of this invention, and, thereby, the range of this invention is not interpreted narrowly.

<Experiment 1: Examination of effect of aqueous solution immersion process>
In Experiment 1, in the production of the polarizing film, the difference in durability of the polarizing film was investigated when the aqueous solution immersion step was performed and when the aqueous solution immersion step was not performed, and when the order of the aqueous solution immersion step was changed. In this example, as an example of a film that can be used as a polarizing film, a commercially available atactic PVA film (degree of polymerization: 2400, degree of saponification: 99%, film thickness: 75 μm) was examined. .

(1) Production of Polarizing Film [Example 1]
First, after a polyvinyl alcohol-based resin film was installed and fixed on a manual uniaxial stretching machine, it was swollen in pure water at 35 ° C. for 3 minutes. After swelling, the polymer film was pulled up from the swelling bath and immersed in an aqueous solution at 55 ° C. containing formaldehyde as a hydrophobizing agent for 2 minutes. The treatment aqueous solution had a weight concentration of 10 wt%, and a solution adjusted to pH 1.7 using hydrochloric acid was used.

  Next, the polymer film was pulled up from the aqueous solution and immersed in an aqueous dye solution at 35 ° C. for 3 minutes. As the dyeing aqueous solution, mixed aqueous solutions having iodine / potassium iodide and boric acid weight concentrations of 0.02 wt% / 3.0 wt% and 3.0 wt%, respectively, were used.

  Next, the polymer film was pulled up from the dyeing bath and immersed in a stretching aqueous solution at 55 ° C. for 5 minutes, and during this immersion, stretching was performed 6 times compared to before swelling. In addition, as the aqueous solution of the stretching bath, a mixed aqueous solution in which the weight concentrations of potassium iodide and boric acid were 3.0 wt% each was used. After stretching, the polymer film was pulled up from the stretching bath and immersed in a 35 ° C. cross-linking immobilization bath for 3 minutes. As the aqueous solution of the cross-linking and fixing bath, a mixed aqueous solution composed of potassium iodide, boric acid, and zinc chloride and having concentrations of 2.5 wt%, 2.5 wt%, and 1.0 wt%, respectively, is used. It was.

  After the cross-linking and fixing, the polymer film was pulled up from the cross-linking and fixing bath and dried at 110 ° C. for 30 minutes. In this way, a polarizing film according to Example 1 was obtained.

[Example 2]
A polarizing film according to Example 2 was obtained in the same manner as in Example 1 except that acetaldehyde was used as a hydrophobizing agent in the aqueous solution immersion step.

[Example 3]
A polarizing film according to Example 3 was obtained in the same manner as in Example 1 except that glyoxal was used as a crosslinking agent in the aqueous solution immersion step.

[Example 4]
A polarizing film according to Example 4 was obtained in the same manner as in Example 1 except that glutaraldehyde was used as a crosslinking agent in the aqueous solution immersion step.

[Comparative Example 1]
A polarizing film according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the aqueous solution immersion step was not performed and the drying temperature was 60 ° C.

[Comparative Example 2]
A polarizing film according to Comparative Example 2 was obtained in the same manner as in Example 1 except that the aqueous solution immersion step was not performed.

[Comparative Example 3]
A polarizing film according to Comparative Example 3 was obtained in the same manner as in Example 1 except that the aqueous solution immersion step was performed after the stretching process and before the cross-linking and fixing process.

[Comparative Example 4]
A polarizing film according to Comparative Example 4 was obtained in the same manner as in Example 1 except that the aqueous solution immersion step was performed after the cross-linking and fixing process and before the drying process.

(2) Evaluation of physical properties [Observation of polarizing film surface by visual observation]
Regarding the polarizing films according to Examples 1 to 4 and Comparative Examples 1 to 4, the surface of the polarizing film was visually observed.

[durability]
About the polarizing film which concerns on Examples 1-4 and Comparative Examples 1-4, according to the following method, the humidification test at 60 degreeC which assumed high temperature / humidity environment preservation | save with the viscoelasticity measurement tester, and low which assumed high temperature preservation | save Durability was judged by performing a heating test in humidity. The reason for adopting the following method is that, in the case of a normal durability confirmation test, the result obtained is not only the change in optical properties and the shape before and after storage for a predetermined period, but also the storage for a predetermined period itself is 1000 hours. It takes about time and considerable time. However, this measuring machine has the advantage that the measurement itself can be completed in a short time in addition to the information regarding the microstructure such as local molecular motion inside the film and the sample length change being obtained continuously and quantitatively. is there.

  As a specific device, DVA-220 manufactured by IT Laboratories is used. Changes in storage elastic modulus (E ′) and changes in tan δ indicating the occurrence state of local molecular motion in a constant strain mode, and further changes in sample length Monitored about. In the humidification test at a constant 60 ° C, the humidification rate is 8% to 95% at 2% / min. In the low humidity test, the heating rate is 2 ° C / min. The case where it heated up to was monitored. At this time, the sample shape was set to a grip length of 15 mm and a sample width of 5 mm, the sample was prepared by slitting from each sample film, and the sample film thickness was determined using a TESA module.

(3) Results The results of visual observation of each polarizing film surface are shown in Table 1 below, and the durability results are shown in FIGS.

  As shown in Table 1, it was found that the surfaces of the polarizing films according to Examples 1 to 4 and Comparative Examples 1 and 2 had no particular problem. On the other hand, it was found that the surface of the polarizing film according to Comparative Examples 3 and 4 that had been subjected to the aqueous solution immersion step after stretching or after cross-linking and fixing had a haze as apparent.

  FIG. 4A shows changes in storage elastic modulus (E ′) with respect to humidification of the polarizing films according to Examples 1 to 4 and changes in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to humidification of the polarizing film which concerns on Examples 1-4. As shown in FIG. 4 (A), the polarizing films according to Examples 1 to 4 show some sub-dispersion at a humidity of about 95%, but no shrinkage occurs as shown in FIG. 4 (B). I understood that.

  FIG. 5 (A) shows the change in storage elastic modulus (E ′) with respect to the heating of the polarizing films according to Examples 1 to 4 and the change in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on Examples 1-4. As shown in FIG. 5 (A), the polarizing films according to Examples 1 to 4 show almost no change in sub-dispersion, and as shown in FIG. In the example, it was found that it remained at about 0.5%.

  6A shows changes in storage elastic modulus (E ′) with respect to humidification of polarizing films according to Comparative Examples 1 and 2, and changes in tan δ indicating the occurrence of local motion. FIG. 6B shows a comparison. It is a drawing substitute graph which shows the change of the sample length change rate with respect to humidification of the polarizing film which concerns on Examples 1 and 2. As shown in FIG. 6 (A), the tendency of tan δ of Comparative Example 1 having a relative humidity near 95% and a low drying temperature was slightly changed, and a sub-dispersion representing local molecular motion was observed. This is considered to be because when the moisture is humidified, when the drying temperature is low and the film contains a large amount of moisture, changes such as dimensional shrinkage are more likely to occur due to the influence of moisture.

  FIG. 7A shows a change in storage elastic modulus (E ′) with respect to heating of the polarizing films according to Comparative Examples 1 and 2 and a change in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on the comparative examples 1 and 2. FIG. As shown in FIG. 7B, it was found that the sample length of Comparative Example 1 having a low drying temperature with heating was contracted as compared with Comparative Example 2 having a high drying temperature. Further, when compared at a position of 150 ° C., it was found that Comparative Example 1 contracted by nearly 4%, while that of Comparative Example 2 at 110 ° C. drying contracted by 2%. This was found to be an order of magnitude larger than Examples 1-4 in FIG.

  FIG. 8A shows a change in storage elastic modulus (E ′) with respect to humidification of the polarizing film according to Comparative Examples 3 and 4, and a change in tan δ indicating the state of occurrence of local motion, and FIG. 8B shows a comparison. 6 is a drawing-substituting graph showing a change in a sample length change rate with respect to humidification of a polarizing film according to Examples 3 and 4; In addition, in order to make a comparison with an Example easy, the result of Example 3 which used the glyoxal for the aqueous solution immersion process was appended, respectively. As shown in FIG. 8 (A), sub-dispersion was observed in Comparative Example 4 in which the aqueous solution immersion step was performed after cross-linking immobilization at a humidity of about 95%, and not only became weak when humidified, but also FIG. 8 (B). As shown in Fig. 4, it was found that sudden contraction also occurred.

  FIG. 9 (A) shows the change in storage elastic modulus (E ′) with respect to the heating of the polarizing film according to Comparative Examples 3 and 4, and the change in tan δ indicating the state of occurrence of local motion. FIG. 7 (B) It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on the comparative examples 3 and 4. FIG. In addition, in order to make a comparison with an Example easy, the result of Example 3 which used the glyoxal for the aqueous solution immersion process was appended, respectively. As shown in FIG. 9B, the shrinkage of Comparative Examples 3 and 4 was confirmed along with the heating, and the shrinkage of Comparative Example 4 in which the aqueous solution immersion step was performed after the cross-linking and fixing was particularly large. When compared at the 150 ° C. position, Example 3 has a shrinkage rate of about 0.5%, whereas Comparative Example 3 is 1.5% and Comparative Example 4 is 2.5%. It was.

  From the above results, it was found that by performing the aqueous solution dipping step before dyeing, the dimensional change is reduced and the moisture resistance and heat resistance are remarkably improved.

<Experiment 2: Examination of optimum pH of aqueous solution>
In Experiment 2, the optimum pH of the aqueous solution used in the aqueous solution immersion process was examined.

(1) Production of Polarizing Film The polarizing films of Samples 1 to 3 were adjusted in the same manner as in Example 2 by adjusting the pH of the aqueous solution in the aqueous solution immersion step to -0.1, -0.9, and -1.5. Was made.
Moreover, the pH of the aqueous solution in the aqueous solution immersion step was adjusted to −0.1, −0.8, and −1.7, and polarizing films of Samples 4 to 6 were produced in the same manner as in Example 3.

(2) Evaluation of physical properties [Observation of polarizing film surface by visual observation]
Regarding the polarizing films according to Samples 1 to 6, the surface of the polarizing film was visually observed.

(3) Results The results of visual observation of the surface of each polarizing film are shown in Table 2 below.

  As shown in Table 2, when the treatment solution pH in the aqueous solution treatment step is smaller than 0, there is a problem that the reaction proceeds too rapidly and the haze increases (samples 1 and 2) or the film breaks. Samples 3-6) were found. From this result, it was found that the pH of the aqueous solution in the aqueous solution treatment step in the present invention is preferably 0 or more. On the other hand, the limit of pH adjustment by acid is around pH 4 for any reagent, and considering that there is a possibility that the film may be dissolved when pH 4 is exceeded, the aqueous solution treatment step of the present invention. It was found that the pH of the aqueous solution is preferably 0 or more and 4 or less.

It is a flowchart which shows an example of the manufacturing method of the polarizing film which concerns on this invention. It is a cross-sectional schematic diagram which shows schematic structure of an example of the liquid crystal display device 1 which can use the polarizing film manufactured using the manufacturing method which concerns on this invention. It is a cross-sectional schematic diagram which shows schematic structure of an example of the color liquid crystal display device 100 which can use the polarizing film manufactured using the manufacturing method which concerns on this invention. FIG. 4A shows changes in storage elastic modulus (E ′) with respect to humidification of the polarizing films according to Examples 1 to 4 and changes in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to humidification of the polarizing film which concerns on Examples 1-4. FIG. 5 (A) shows the change in storage elastic modulus (E ′) with respect to the heating of the polarizing films according to Examples 1 to 4 and the change in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on Examples 1-4. 6A shows changes in storage elastic modulus (E ′) with respect to humidification of polarizing films according to Comparative Examples 1 and 2, and changes in tan δ indicating the occurrence of local motion. FIG. 6B shows a comparison. It is a drawing substitute graph which shows the change of the sample length change rate with respect to humidification of the polarizing film which concerns on Examples 1 and 2. FIG. 7A shows a change in storage elastic modulus (E ′) with respect to heating of the polarizing films according to Comparative Examples 1 and 2 and a change in tan δ indicating the state of occurrence of local motion, and FIG. It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on the comparative examples 1 and 2. FIG. FIG. 8A shows a change in storage elastic modulus (E ′) with respect to humidification of the polarizing films according to Comparative Examples 3 and 4, and a change in tan δ indicating the state of occurrence of local motion. FIG. 8B shows a comparison. 6 is a drawing-substituting graph showing a change in a sample length change rate with respect to humidification of a polarizing film according to Examples 3 and 4; FIG. 9 (A) shows the change in storage elastic modulus (E ′) with respect to the heating of the polarizing film according to Comparative Examples 3 and 4, and the change in tan δ indicating the state of occurrence of local motion. FIG. 7 (B) It is a drawing substitute graph which shows the change of the sample length change rate with respect to the heating of the polarizing film which concerns on the comparative examples 3 and 4. FIG. It is a drawing substitute graph which shows the XRD measurement result at the time of changing the process in a polarizing film manufacturing process. It is a drawing substitute graph which shows the XRD measurement result for every process in a polarizing film manufacturing process. It is a schematic diagram which shows the microstructure change in the film estimated from FIG. 10 and FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 11 Polarizing film 12 Electrode 13 Substrate 14 Liquid crystal layer 15 Orientation film 16 Color filter 17 Spacer 18 Light reflection film 19 Smoothing film 20 Light source 21 Optical function sheet 100 Color liquid crystal display device 101 Diffusion or passage region 102 Second primary color Light emitting area 103 Third primary color light emitting area 104 Light absorbing layer

Claims (8)

At least before the dyeing step in the production of the polarizing film,
A method for producing a polarizing film, comprising at least a step of immersing the film in an aqueous solution containing a crosslinking agent or a hydrophobizing agent.   The method for producing a polarizing film according to claim 1, wherein the film is a polyvinyl alcohol film.   The method for producing a polarizing film according to claim 1 or 2, wherein the pH of the aqueous solution is 0 or more and 4 or less.   The method for producing a polarizing film according to claim 1, wherein the cross-linking agent is a polyvalent aldehyde.   The method for producing a polarizing film according to claim 4, wherein the polyvalent aldehyde is glyoxal or glutaraldehyde.   The method for producing a polarizing film according to any one of claims 1 to 3, wherein the hydrophobizing agent is a monoaldehyde.   The method for producing a polarizing film according to claim 6, wherein the monoaldehyde is formaldehyde or acetaldehyde. At least before the dyeing step in the production of the polarizing film,
A method for producing a polarizing plate, comprising at least a step of immersing a film in an aqueous solution containing a cross-linking agent or a hydrophobizing agent and at least a step of producing a polarizing film.