JP6010841B2 - ORGANIC EL DISPLAY DEVICE AND POLARIZING ELEMENT FOR ORGANIC EL DISPLAY DEVICE - Google Patents

Description

  The present invention relates to a polarizing element for an organic EL display device using a dichroic dye other than a photochromic compound and a photochromic compound (hereinafter, the polarizing element for an organic EL display device is also referred to as a polarizing element for OLED), and an organic EL provided with the polarizing element. The present invention relates to a display device and a high transmittance linearly polarizing plate for an organic EL display device.

An image display device (hereinafter referred to as an organic EL display device or OLED display) having an organic EL element (Organic Light Emitting Diode) (hereinafter also referred to as OLED) is easy to be thinned and has a wide viewing angle. Widely used as a display device for telephones, tablet PCs and the like.
Since the OLED includes a reflective metal electrode inside the device, external light is easily reflected. In particular, when an OLED display is used in an environment with strong external light such as outdoors, external light is reflected on the screen, which causes a problem that the visibility of the screen is significantly reduced.

As a method for preventing the visibility of the image display device from being deteriorated due to reflection of external light, there is a means for applying an anti-glare treatment to the screen surface. In this means, external light incident on the display device from the screen has various configurations. The reflected light that hits the member and reflects cannot be prevented.
As another method for preventing the deterioration of visibility, there is known a means for providing an image display device with a circularly polarizing plate made of a retardation plate such as a linear polarizing plate and a quarter-wave plate, and the antireflection performance is improved by the means. Organic EL display devices have been proposed (Patent Document 1 and Patent Document 2).
By using the circularly polarizing plate, reflected light from the outside can be considerably reduced. However, when used outdoors, the external light is strong, the reflected light cannot be reduced sufficiently, and the visibility cannot be increased. In order to prevent the outdoor visibility from decreasing, the light emitted from the organic EL element is increased to increase the display light reaching the display screen. However, in order to enhance the light emission of the organic EL element, it is necessary to increase the amount of energization, which causes a fatal problem of increasing power consumption and shortening the life of the organic EL.

As a means for solving this problem, a method has been proposed in which a linearly polarizing plate is prepared using a dichroic photochromic dye as a dichroic dye, and a circularly polarizing plate comprising the linearly polarizing plate and a retardation plate is used. (Patent Document 3). This circularly polarizing plate is colored by the photochromic dye when used outdoors with strong ultraviolet rays and exhibits polarization performance, can absorb reflected light, and decolorizes the photochromic dye when used indoors where UV rays are weak. It has the feature of transmitting light. However, this circularly polarizing plate has no polarization function at all indoors where ultraviolet rays are weak, and reflects all the light from the outside. If there is no antireflection function even in an environment with weak ultraviolet rays, the display image becomes difficult to see due to glare due to the metal reflected light of the OLED, and reflection of light such as room lighting cannot be prevented.
Japanese Patent Laid-Open No. 8-322138 Japanese Patent Laid-Open No. 9-127858 JP 2008-122485 A

  The object of the present invention is to exhibit an excellent antireflection function when used in an environment with strong external light, to sufficiently reduce the reflected light, and improve the visibility in outdoor use with strong ultraviolet light, An object of the present invention is to provide an organic EL display device capable of maintaining a certain antireflection function even in an indoor environment where external light is weak and ensuring visibility in indoor use, and a polarizing element suitable for the organic EL display device.

  In order to solve the above-mentioned problems, the inventors have prepared a photochromic compound that is colored and decolored by the intensity of light, particularly ultraviolet light, a circularly polarizing plate containing a dichroic dye other than the photochromic compound, particularly the dichroic dye. In combination with a circularly polarizing plate comprising a linearly polarizing plate containing λ / 4 and a λ / 4 retardation plate, the antireflection function is improved, and the visibility of organic EL display devices in environments with strong ultraviolet rays such as outdoors is improved. I found out that I can do it. In particular, when a linear polarizing plate having a higher light transmittance than the conventional one is used as a circular polarizing plate, it has an excellent anti-reflection function when used outdoors with strong ultraviolet rays. However, by increasing the display light from the OLED on the display screen, it was found that the visibility in the outdoors was improved, and the present invention was completed.

The present invention relates to the following 1 to 16.
1. An organic EL display device having a polarizing element using a photochromic compound in combination with a polarizing element film containing a dichroic dye other than the photochromic compound.
2. The polarizing element is a polarizing element obtained by laminating a photochromic compound-containing layer on a circularly polarizing plate comprising a linear polarizing plate having a polarizing element film containing the dichroic dye and a λ / 4 retardation plate, or 2. The organic EL display device according to 1 above, which is a polarizing element obtained by laminating a linear polarizing plate having a polarizing element film containing a photochromic compound together with the dichroic dye and a λ / 4 retardation plate.
3. 3. The organic EL display device according to 1 or 2 above, wherein a single transmittance in visible light of a linearly polarizing plate having a polarizing element film containing the dichroic dye is greater than 42% and 70% or less.
4). An organic EL display device having both a polarizing element film containing a dichroic dye other than a photochromic compound and a photochromic compound-containing layer, or a polarizing element film containing both the dichroic dye and the photochromic compound Polarizing element.
5. A photochromic compound-containing layer is laminated on a circularly polarizing plate comprising a linear polarizing plate having a polarizing element film containing the dichroic dye and a λ / 4 retardation plate, or a photochromic compound together with the dichroic dye. A polarizing element for an organic EL display device, in which a linear polarizing plate having a polarizing element film containing λ / 4 and a λ / 4 retardation plate are laminated.
6). 6. The polarizing element for an organic EL display device according to 4 or 5 above, wherein the linear polarizing plate has a single transmittance in visible light of greater than 42% and 70% or less.
7). The polarizing element for organic EL display devices according to any one of 4 to 6, wherein the linear polarizing plate has an orthogonal transmittance of 0.1 to 20% in visible light.

8). The polarizing element for organic EL display devices according to any one of 4 to 7, wherein the color of the linearly polarizing plate is neutral gray.
9. The polarizing element film is
Below (1)-(3)
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) a dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and
(3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less,
9. The polarizing element for an organic EL display device according to 8 above, which is a polarizing element film containing at least two dyes selected from the dyes.
10. The polarizing element for organic EL display devices according to any one of 4 to 9 above, wherein the photochromic compound is a compound that is colored by ultraviolet light and decolored by visible light or heat.
11 The concentration of the photochromic compound in the photochromic compound-containing layer is 0.1 to 20% by mass relative to the total amount of the containing layer, or in a linearly polarizing element film containing both the dichroic dye and the photochromic compound The polarizing element for organic EL display devices as described in any one of 5 to 10 above, wherein the concentration of the photochromic compound is from 0.1 to 50% by mass based on the total amount of the linearly polarizing element film.
12 The polarizing element for organic EL display devices according to any one of 5 to 11 above, wherein the photochromic compound is oriented in the same direction as the polarization direction of the laminated linearly polarizing plate in the photochromic compound-containing layer.
13. The linearly polarized light for an organic EL display device having an orthogonal transmittance of 0.1 to 20% in visible light, a single transmittance of greater than 42% and 70% or less, and a hue of neutral gray. Board.

14 As a dichroic dye,
Below (1)-(3)
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) a dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and
(3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less,
14. The linearly polarizing plate for an organic EL display device as described in 13 above, which contains at least two dyes selected from the dyes described above.
15. A linear polarizing plate having a polarizing element film containing a dichroic dye other than a photochromic compound, a circularly polarizing plate comprising a λ / 4 retardation plate, and a photochromic compound-containing layer are laminated, or the above two colors A polarizing element in which a linear polarizing plate having a polarizing element film containing a photochromic compound together with a functional dye and a λ / 4 retardation plate are laminated.
16 Polarizing element film as dichroic dye,
Below (1)-(3)
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) a dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and
(3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less,
16. The polarizing element according to 15 above, wherein the polarizing element film contains at least two dyes selected from the dyes, and the hue thereof is neutral gray.

  In the present invention, the amount of reflected light emitted from the display screen is remarkably reduced outdoors where the ultraviolet rays are strong, and the amount of light emitted from the organic EL element with respect to the amount of reflected light emitted from the display screen is also reduced. The ratio (contrast) can be increased. As a result, the visibility on the display surface in the organic EL display device is remarkably improved. In particular, when a linear polarizing plate having a high light transmittance is used, the amount of light emitted from the organic EL element can be increased from the display screen, so that the amount of reflected light emitted from the display screen can be increased. The effect that the ratio (contrast) of the emitted light quantity from the display screen of the light emitted from the organic EL element can be increased can be achieved. Therefore, the visibility in the outdoors can be remarkably improved without increasing the light emission amount of the organic EL element. As a result, the power consumption of the OLED is saved, and the effect that the lifetime of the OLED is not shortened is achieved.

1 is a longitudinal sectional view showing an embodiment of an organic EL display device of the present invention.

The present invention will be described below.
The polarizing element used in the organic EL display device of the present invention is characterized in that a photochromic compound is used in combination with a polarizing element film containing a dichroic dye other than a photochromic compound as a dichroic dye.
Although it does not specifically limit as a polarizing element which used a photochromic compound together, As a specific example, the polarizing element containing the polarizing element film containing dichroic dyes other than a photochromic compound, and the resin layer containing a photochromic compound, and the said Examples thereof include a polarizing element having a polarizing element film containing both a dichroic dye and a photochromic compound.
Usually, as a polarizing element used for an organic EL display device, a circularly polarizing plate is preferable. Therefore, as the polarizing element of the present invention, a linearly polarizing plate having a polarizing element film containing a dichroic dye other than a photochromic compound. And a polarizing plate in which a photochromic compound-containing layer is laminated on a circularly polarizing plate in which a λ / 4 retardation plate is laminated, or a linear polarizing plate having a polarizing element film containing both the dichroic dye and the photochromic compound, and λ / Examples thereof include a polarizing element in which four retardation plates are laminated. The linearly polarizing plate used in the present invention is preferably a polarizing plate having a higher light transmittance than a commonly used linearly polarizing plate. For this reason, the contrast value of the linear polarizing plate is also lower than in the normal case.
As the polarizing element of the present invention, a polarizing element in which a photochromic compound-containing layer is laminated on a circularly polarizing plate containing the dichroic dye is preferable from the viewpoint of ease of production.
Hereinafter, the linearly polarizing plate, the photochromic compound-containing layer and the like used in the present invention will be sequentially described.

<Linear polarizing plate>
First, the linear polarizing plate containing the said dichroic dye used for the polarizing element of this invention independently is demonstrated below. In the present specification, the phrase “linear polarizing plate containing the dichroic dye alone” means “linear polarizing plate containing the dichroic dye not using a photochromic compound”.
As the linear polarizing plate, a linear polarizing plate containing the normal dichroic dye alone can be used, but a linear polarizing plate having a high light transmittance is used in order to improve outdoor visibility. It is preferable to do. First, the linearly polarizing plate will be described below.
The single transmittance of the linearly polarizing plate of the present invention can be used as long as it is 40% or more in the visible light region (wavelength region of 380 to 700 nm), but is usually preferably higher than 42%, more preferably 45% or more, 46% or more is more preferable, and 47% or more is particularly preferable. Most preferably, it is 48% or more, and may be 49% or more or 50% or more. The upper limit is not particularly limited as long as the effect of the present invention is achieved. Usually, it is 70% or less, preferably 65% or less, more preferably 60% or less, and further preferably 55% or less. In this specification, a linear polarizing plate having a single transmittance exceeding 42% is referred to as a high transmittance linear polarizing plate.
The orthogonal transmittance in the visible light region of the linear polarizing plate is usually about 0.1% to 30%, preferably 0.1% to 20%. In some cases, it is 1% to 20%, preferably 2% to 20%, more preferably 5% to 20%, and still more preferably 7% to 15%.
“Single transmittance” means the transmittance when one polarizing plate is used, and is measured by a method based on JIS Z8701: 1999. “Orthogonal transmittance” refers to the transmittance when two polarizing plates are stacked such that their absorption axes are orthogonal.
A more preferable linearly polarizing plate is a linearly polarizing plate having both the above preferable single transmittance and the above preferable orthogonal transmittance. The single transmittance is 50% or more and 60% or less, and the orthogonal transmittance is 5% or more. A polarizing plate that is 15% or less is most preferred.

  The linearly polarizing plate used in the present invention is subjected to dyeing treatment with a dichroic dye, stretching treatment, and curing with boric acid or the like, if necessary, on a base film (for example, a polyvinyl alcohol resin film) according to a conventional method. A polarizing element film can be produced by applying an agent treatment and the like, and can be produced by bonding a transparent protective film to one or both sides of the obtained polarizing element film as necessary. Either order may be sufficient as the order of the said dyeing | staining process and extending | stretching process, and you may carry out simultaneously. Moreover, you may perform the said extending | stretching process simultaneously with a hardening | curing agent process. The curing agent treatment is usually performed simultaneously with the dyeing treatment and / or after the dyeing treatment.

As the base film used for the linear polarizing plate, any resin film that can be used as a polarizing plate can be used, and a polyvinyl alcohol-based resin film is usually used. The polyvinyl alcohol-based resin film is a resin film mainly composed of a polymer of vinyl alcohol or a modified product thereof, and among the repeating units in the polymer, a component derived from vinyl alcohol or a modified product thereof is at least in a molar ratio. The polymer film is 40%, preferably 50 to 100%, more preferably 80 to 100%.
Specifically, a polyvinyl alcohol film obtained by saponifying polyvinyl acetate, which is a polymer of vinyl acetate; vinyl acetate and other monomers copolymerizable therewith, such as unsaturated carboxylic acids, olefins , Vinyl ethers, unsaturated sulfonic acids, unsaturated amines, acrylamide, polyvinyl alcohol copolymer films obtained by saponifying a copolymer (polyvinyl acetate copolymer) with acrylic acid derivatives, etc .; and Examples thereof include polyvinyl alcohol-modified films obtained by modifying the above polymers and copolymers with olefins or unsaturated carboxylic acids. Specific examples include, for example, a polyvinyl alcohol resin film, the above copolymer resin film, a polyvinyl acetal film (ethylene vinyl acetate resin film) and the like. Among these, dichroic dye adsorptivity and orientation From the viewpoint, a polyvinyl alcohol resin film is preferable.

The degree of polymerization of the polyvinyl alcohol-based resin used for the linear polarizing plate is usually in the range of about 1000 to 10,000, preferably about 1500 to 7000, more preferably about 2000 to 7000. As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate polymer or copolymer is usually used, and the degree of saponification is usually about 85 to 100 mol%, preferably 98 to 100 mol%. is there.
Although the thickness of the polyvinyl alcohol-type resin film used as a raw material is not specifically limited, Usually, about 10 micrometers-150 micrometers, Preferably it is about 20-100 micrometers.

Any dichroic dye may be used as long as the dichroic dye used in the linear polarizing plate exhibits a dichroism in the visible light region due to stretching of the base film, but a dye excellent in durability is preferable.
Specific examples of the dichroic dye used in the linear polarizing plate include C.I. I. direct. Yellow 12, C.I. I. direct. Yellow 28, C.I. I. direct. Yellow 44, C.I. I. direct. Yellow 142; C.I. I. direct. Orange 26, C.I. I. direct. Orange 39, C.I. I. direct. Orange 71, C.I. I. direct. Orange 107; I. direct. Red 2, C.I. I. direct. Red 31, C.I. I. direct. Red 79, C.I. I. direct. Red 81, C.I. I. direct. Red 117, C.I. I. direct. Red 247; C.I. I. direct. Green 80, C.I. I, direct. Green 59; C.I. I. Direct Blue 1, C.I. I. Direct Blue 71, C.I. I. Direct Blue 78, C.I. I. Direct Blue 168, C.I. I. Direct Blue 202; C.I. I. Direct Violet 9, C.I. I. Direct violet 51; C.I. I. Direct Brown 106, C.I. I. Direct brown 223 etc. can be illustrated.
Further, depending on the purpose, dyes developed for polarizing plates as disclosed in WO2009 / 057676A1, WO2007 / 145210A1, WO2006 / 057214A1, and JP-A-2004-251963 can also be used. These dyes are used as free acids, alkali metal salts (for example, Na salt, K salt, Li salt), ammonium salts, and salts of amines.

One or a plurality of dichroic dyes may be used for the linear polarizing plate, and usually a plurality of dichroic dyes are preferably used. By using at least one dye selected from the following dyes (1) to (3), more preferably at least one of the following dyes (1) to (3), the hue is neutral gray. Since the polarizing plate which is can be produced, it is preferable.
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) A dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and (3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less.

Examples of the dichroic dye (1) having λmax of 400 nm or more and less than 500 nm include dichroic dyes having a λmax of 400 nm or more and less than 500 nm among yellow or orange dyes. Examples of the dichroic dye (2) having λmax of 500 nm or more and less than 600 nm include dichroic dyes having a λmax of 500 nm or more and less than 600 nm among Red or Violet dyes. Examples of the dichroic dye (3) having λmax of 600 nm to 700 nm include dichroic dyes having a λmax of 600 nm to 700 nm among Blue and Green dyes.
Even if the dichroic dye used when producing the neutral gray polarizing plate is a dye included in the same group of any one of the dichroic dyes (1) to (3), it is absorbed by the individual dyes. Since the wavelengths are different, a plurality of dyes included in the same group may be used if necessary. For example, 4 to 5 kinds of dyes in the above dichroic dyes (1) to (3) group, or The above dichroic dyes may be used. As one preferred embodiment, one type of orange dichroic dye, one type of red dichroic dye, and a mode of using two types of blue and green as the dichroic dye (3) are used. Can be mentioned.
The content ratio of each dye in the staining liquid is not particularly limited as long as the hue of the obtained polarizing element film can be neutral gray. When using at least one of each of the above dyes (1) to (3), for example, dichroic dye (1): dichroic dye based on the dichroic dye (1) in mass ratio (2): Dichroic dye (3) = 1: 0.1-3: 1-8, more preferably in a ratio of about 1: 0.2-2: 2-7. By appropriately adjusting the content ratio of each dye in the dyeing liquid within the above range, a polarizing plate having more preferable hue and optical performance as a neutral gray polarizing plate can be obtained.
The linearly polarizing plate used in the present invention may be a color polarizing plate obtained by using the above dichroic dyes alone or in combination.

The dichroic dye used for the linear polarizing plate is a dichroic dye having a dichroic ratio defined by the following formula (3) in the range of 20 to 50, preferably in the range of 25 to 45. preferable.
In the present specification, the “dichroic ratio” in the case of “dye dichroic ratio” is defined as follows. A polarizing plate using only the dye as a dichroic dye is prepared, and the transmittance when the single polarizing plate is used is the single transmittance Ts, and the absorption axis direction of the two polarizing plates is the same. The transmittance when the two polarizing plates are stacked so that the absorption axes are orthogonal to each other is defined as the orthogonal transmittance Tc. Each transmittance is calculated by the following formula (1) by obtaining a spectral transmittance τλ at predetermined wavelength intervals dλ (here, 5 nm) in a wavelength region of 380 to 700 nm.

In the formula, Pλ represents a spectral distribution of standard light (C light source), yλ represents a 2 ° visual field color matching function, and τλ represents a spectral transmittance. The degree of polarization Py is obtained from the parallel transmission Tp and the orthogonal transmission Tc by the following formula (2).
Py = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100 Formula (2)
From the degree of polarization Py and the single transmittance Ts, the dichroic ratio Rd is obtained by the following formula (3).
Rd = log {Ts / 100 * (1-Py / 100)} / log {Ts / 100 * (1 + Py / 100)} Formula (3)

What is necessary is just to manufacture the linearly-polarizing plate used by this invention in accordance with a well-known manufacturing method, for example, it can manufacture as follows. However, in the case of the high transmittance linear polarizing plate used in the present invention, it is necessary to appropriately adjust the dyeing density of the dichroic dye so that the single transmittance is in the above range.
Usually, before the dyeing | staining process with a dichroic dye, the swelling process of a polyvinyl alcohol-type resin film is given (it is also called a swelling process). The swelling treatment is performed by immersing in a swelling treatment solution at 20 to 50 ° C. for 30 seconds to 10 minutes. The swelling treatment solution is preferably water. If necessary, the swelling treatment may be performed with a water-soluble organic solvent such as glycerin, ethanol, ethylene glycol, propylene glycol, or low molecular weight polyethylene glycol, or a mixed solution of water and a water-soluble organic solvent. Since the film swells even during the dyeing treatment, the swelling step can be omitted when it is desired to shorten the time required for producing the polarizing element film.

The dyeing treatment with the dichroic dye is carried out in accordance with a conventional method, using the above-mentioned dichroic dye, and a polyvinyl alcohol in a dyeing solution containing the dichroic dye, preferably a dyeing solution in which the dichroic dye is dissolved. This is performed by immersing the resin film. You may perform the dyeing | staining process of the resin film by a dichroic dye simultaneously with the following extending process.
Water is preferred as the solvent for the dye solution of the dichroic dye. The dye concentration in the dye solution of the dichroic dye varies depending on the dyeing conditions and cannot be generally stated, but is usually about 0.01 to 5 g / L, preferably about 0.01 to 2 g / L with respect to the dye solution. More preferably, it is about 0.02 to 1 g / L, and most preferably about 0.02 to 0.9 g / L. When a plurality of dichroic dyes are used, it is preferable that the concentration of the total amount of the dyes used is in the above range.
The dyeing solution containing the dichroic dye may contain an auxiliary such as a dyeing auxiliary as necessary. Examples of the dyeing aid include inorganic salts such as mirabilite and sodium tripolyphosphate. The density | concentration of the dyeing adjuvant at that time is about 0.01-10 g / L with respect to the total amount of the dyeing | staining liquid, Preferably it is about 0.05-5 g / L. When a plurality of dyeing assistants are used, the concentration of the total amount of dyeing assistants is preferably in the above range.
The temperature of the dyeing liquid in the dyeing treatment with the dichroic dye is about 20 to 60 ° C, preferably about 30 to 55 ° C. There is no problem if the dipping time is a time that can be dyed to the above concentration, and it is in the range of about 10 to 500 seconds, preferably about 30 to 400 seconds.

For the orientation of the dichroic dye, the stretching treatment may be performed together with the dyeing treatment. In addition, the stretching process may be performed in a plurality of times. In some cases, the stretching treatment may be performed after swelling and before the dyeing treatment.
In the present invention, it is preferable to stretch the polarizing element film by stretching a polyvinyl alcohol resin film dyed with a dichroic dye at a predetermined magnification (preferably uniaxial stretching). The stretching method in the stretching treatment may be either a dry stretching method or a wet stretching method, but a wet stretching method is preferred. The wet stretching method is usually a method in which a solution composed of water, a water-soluble organic solvent, or a mixed solution thereof is heated and stretched while immersing a polyvinyl alcohol-based resin film in the heated solution. The stretching ratio cannot be generally specified depending on the thickness of the original film, but is usually about 2 to 20 times, preferably about 3 to 10 times that of the original film.
By containing a curing agent in the stretching treatment solution, the curing agent treatment may be performed simultaneously with the stretching treatment. As the curing agent at that time, the curing agent exemplified in the section of the curing agent treatment below can be used, a boron compound is preferable, and boric acid is more preferable. Although content of the hardening | curing agent in the extending | stretching process solution at this time changes with kinds of hardening | curing agent, it cannot say unconditionally, It is about 0.1-10.0 mass%, Preferably it is 0.5-5.0 mass. %.
As the stretching method, a method of uniaxial stretching between two rolls having different speeds is preferable. The total draw ratio of the film obtained by the drawing treatment with respect to the raw film is about 2.0 to 10.0 times, preferably 4.0 to 7.0 times. The temperature of the treatment solution in the stretching treatment is about 30 to 60 ° C.

It is preferable to perform a curing agent treatment after the dyeing treatment with the dichroic dye. Curing agent treatment refers to treating the film with a solution containing a curing agent simultaneously with and / or after the dyeing treatment. As the curing agent treatment, a method of immersing a film subjected to a dyeing treatment in the solution is preferable, but a method of applying or applying the solution to a film subjected to the dyeing treatment may be used.
Examples of the curing agent used in the curing agent treatment include boron compounds such as boric acid or salts thereof (alkali metal salts such as borax, borax ammonium, etc.), polyvalent aldehydes such as glyoxal or glutaraldehyde, biuret types, Polyisocyanate compounds such as isocyanurate type or block type, titanium compounds such as titanium oxysulfate, ethylene glycol glycidyl ether, polyamide epichlorohydrin, and the like can be used. Usually, boron compounds are preferred, and boric acid is more preferred. As the solvent for the curing agent treatment solution, water, a water-soluble organic solvent, a mixed solvent thereof or the like can be used, and water is preferable.
The curing agent concentration of the curing agent treatment solution varies depending on the type of the curing agent and cannot be generally specified, but is usually about 0.1 to 10% by mass, preferably about 1 to 6% by mass. About 1-6.0 mass% is preferable. 10-60 degreeC is preferable and the processing temperature of a hardening | curing agent process has more preferable 30-60 degreeC. The treatment time is preferably 30 seconds to 6 minutes, and more preferably 1 to 5 minutes.

In the preferable aspect of this invention, since a hardening | curing agent process and extending | stretching process are performed in boric-acid aqueous solution, boric acid is contained in a polyvinyl alcohol-type resin film. The content of boric acid in the polarizing element film at this time is obtained by heating the obtained polarizing element film in pure water to completely dissolve it, adding a phenolphthalein indicator, and performing neutralization titration with an aqueous sodium hydroxide solution. Can be determined by
The boric acid content in the polarizing element film of the present invention is 5 to 40% by mass, more preferably 10 to 25% by mass. The boric acid content in the polarizing element film can be adjusted by changing the concentration of the solution, the immersion time, the solution temperature, and the stretching ratio in the stretching treatment or the curing agent treatment.

  After each step of these dyeing treatment, stretching treatment, and curing agent treatment, the film surface may be washed for the purpose of removing dyes and curing agents deposited on the film surface, adhering foreign matter, or the like, if necessary. Usually, it is preferable to wash with water, the temperature of the cleaning solution is about 10 to 60 ° C, and the cleaning time is about 1 second to 5 minutes. Washing may be performed once or multiple times as necessary.

The polarizing element film that has been subjected to the stretching treatment is washed as necessary and then dried. The drying temperature in a drying process is about 30-70 degreeC normally, Preferably it is about 40-65 degreeC. The drying time is about 10 to 500 seconds, preferably about 60 to 350 seconds.
The thickness of the obtained polarizing element film is preferably about 10 μm to 40 μm, and more preferably 15 μm to 30 μm.

The polarizing element film thus obtained can be made into a polarizing plate by laminating a transparent protective film excellent in optical transparency, mechanical strength, and isotropy on one surface or both surfaces thereof. Examples of the compound that forms the protective film include cellulose acetate films, acrylic films, fluorine films such as tetrafluoroethylene / hexafluoropropylene copolymers, polyester resins, polyolefin resins, and polyamide resins. A film or the like is used. A triacetyl cellulose (TAC) film or a cycloolefin film is preferably used. The thickness of the protective film is usually 40 to 200 μm.
Examples of the adhesive (adhesive) that can be used to bond the polarizing element film and the protective film include polyvinyl alcohol adhesives, urethane emulsion adhesives, acrylic adhesives, polyester-isocyanate adhesives, and the like. A polyvinyl alcohol-based adhesive is preferred.

A transparent protective layer may be further provided on the surface of the obtained polarizing plate. Examples of the protective layer include a hard coat layer made of an acrylic resin or a polysiloxane resin, and a protective layer made of a urethane resin. Further, an AR layer (antireflection layer) may be provided on the protective layer. The AR layer can be formed, for example, by depositing or sputtering a material such as silicon dioxide or titanium oxide, or by thinly applying a fluorine-based material.
In the present invention, since the linearly polarizing plate is usually used for producing a circularly polarizing plate, in that case, a λ / 4 retardation plate is laminated on one surface of the polarizing plate as described below. The above-mentioned protective layer or the like is usually not provided on the surface. In addition, when laminating the photochromic compound-containing layer, it is usually laminated on the outer surface of the circularly polarizing plate on the linearly polarizing plate side (the surface on which the λ / 4 retardation plate of the linearly polarizing plate is not laminated). Therefore, it is not necessary to provide the protective layer or the like on any surface of the linearly polarizing plate.

<Production of circularly polarizing plate>
A circularly polarizing plate is produced by laminating a retardation plate to the linearly polarizing plate obtained above. Usually, a λ / 4 retardation plate (preferably a quarter-wave plate) is used as the retardation plate, and the slow axis (refractive index in the plane) of the λ / 4 retardation plate (preferably a quarter-wave plate). Are laminated so that the angle between the absorption axis of the linearly polarizing plate and the absorption axis of the linearly polarizing plate is 45 °. The material of the retardation plate is not particularly limited, and known materials such as a polymer film, a liquid crystal film, and a film in which a liquid crystal compound is aligned can be used. The retardation plate may be one or may have a multilayer structure of two or more. Moreover, it is preferable to produce a broadband circularly polarizing plate using a broadband quarter-wave plate having a quarter-wave plate characteristic in the entire visible light region.
It does not specifically limit as an adhesive used for bonding of the said linearly-polarizing plate and phase difference plate, The well-known adhesive with high transparency used for preparation of a normal circularly-polarizing plate can be used.
The circularly polarizing plate composed of the high transmittance linearly polarizing plate and the λ / 4 retardation plate used in the present invention is referred to as a high transmittance circularly polarizing plate for convenience.

<Combination of photochromic compounds>
The polarizing element for OLED of the present invention is characterized in that a photochromic compound is used in combination with the polarizing element film containing the dichroic dye.
As a preferable mode in which the photochromic compound is used in combination, a mode in which the photochromic compound-containing layer is laminated on a circularly polarizing plate having a polarizing element film containing the chromatic dye, or a dichroic dye other than the photochromic compound is included. Examples thereof include a method in which a polarizing element film contains a photochromic compound together with the dichroic dye to form a polarizing element film containing both the dichroic dye and the photochromic compound.
In the former case, the method for forming the photochromic-containing layer laminated on the circularly polarizing plate is not particularly limited. For example, a photochromic compound-containing resin film may be laminated on the surface of the linearly polarizing plate in the circularly polarizing plate, or a photochromic compound-containing resin solution may be applied and dried to form a photochromic-containing layer. Usually, a method of laminating a photochromic compound-containing resin film is preferred.
In the latter case, the obtained dichroic film containing both the dichroic dye and the photochromic compound is obtained in the same manner as the polarizing element film containing the dichroic dye alone. The OLED polarizing element of the present invention can be obtained by forming a linearly polarizing plate containing both a dye and a photochromic compound and laminating a λ / 4 retardation plate on the linearly polarizing plate in the same manner as described above.
In the polarizing element for OLED of the present invention, the concentration of the photochromic compound in the above-mentioned photochromic compound-containing layer or the polarizing element film containing both the dichroic dye and the photochromic compound is such that the photochromic compound is in a state without ultraviolet rays. The concentration is such that the transmittance of light at 550 nm of the circularly polarizing plate not contained is lowered within a range of usually about 1 to 7%, preferably about 2 to 6%, more preferably 2 to 5%.

<Photochromic compound>
The photochromic compound used in the present invention can be used without particular limitation as long as it is a compound having photochromic properties that are colored and decolored depending on the intensity of light. A compound having a positive photochromic property that changes to a colored state when irradiated with ultraviolet rays and changes to a decolored state by irradiation with visible light or heat is preferable.
Examples of the photochromic compound include spiropyran compounds, spirooxazine compounds, diarylethene compounds, fulgide compounds, naphthopyran compounds, hexaarylbisimidazole compounds, and the like. These can be used alone or in combination of two or more. Of these, spiropyran compounds and hexaarylbisimidazole compounds are preferred.

  The spiropyran compound is a compound having a spiropyran structure in which a pyran ring is spiro-condensed. Examples of the compound include 1,3,3-trimethylindolino-6′-nitrobenzopyrospirane, 1 ′, 3. ', 3'-trimethylspiro (2H-1-benzopyran-2,2'-indoline), 1', 3 ', 3'-trimethylspiro-8-nitro (2H-1-benzopyran-2,2'-indoline) ), 1 ′, 3 ′, 3′-trimethyl-6-hydroxyspiro (2H-1-benzopyran-2,2′-indoline), 1 ′, 3 ′, 3′-trimethylspiro-8-methoxy (2H—) 1-benzopyran-2,2′-indoline), 5′-chloro-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro (2H-1-benzopyran-2,2′-indolin ), 6,8-dibromo-1 ′, 3 ′, 3′-trimethylspiro (2H-1-benzopyran-2,2′-indoline), 6,8-dibromo-1 ′, 3 ′, 3′-trimethyl Spiro (2H-1-benzopyran-2,2′-indoline), 8-ethoxy-1 ′, 3 ′, 3 ′, 4 ′, 7′-pentamethylspiro (2H-1-benzopyran-2,2′- Indoline), 5'-chloro-1 ', 3', 3'-trimethylspiro-6,8-dinitro (2H-1-benzopyran-2,2'-indoline), 3,3,1-diphenyl-3H- Naphtho- (2,1-13) pyran, 1,3,3-triphenylspiro [indoline-2,3 ′-(3H) -naphtho (2,1-b) pyran], 1- (2,3, 4,5,6-pentamethylbenzyl) -3,3-dimethylspiro Indoline-2,3 ′-(3H) -naphtho (2,1-b) pyran], 1- (2-methoxy-5-nitrobenzyl) -3,3-dimethylspiro [indoline-2,3′-naphtho (2,1-b) pyran], 1- (2-nitrobenzyl) -3,3-dimethylspiro [indoline-2,3′-naphtho (2,1-b) pyran], 1- (2-naphthyl) Methyl) -3,3-dimethylspiro [indoline-2,3′-naphtho (2,1-b) pyran], 1,3,3-trimethyl-6′-nitro-spiro [2H-1-benzopyran-2 , 2 ′-(2H) -indole] and the like.

  Examples of the spirooxazine compound include 1,3,3-trimethylspiro [indolino-2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine], 5-methoxy- 1,3,3-trimethylspiro [indolino-2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine], 5-chloro-1,3,3-trimethylspiro [indolino- 2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine], 4,7-diethoxy-1,3,3-trimethylspiro [indolino-2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine], 5-chloro-1-butyl-3,3-dimethylspiro [indolino-2,3 ′-(3H) naphtho (2,1-b) (1 , 4) Oxazine], 1,3,3,5-tetramethyl-9 -Ethoxyspiro [indolino-2,3 '-(3H) naphtho (2,1-b) (1,4) oxazine], 1-benzyl-3,3-dimethylspiro [indoline-2,3'-(3H ) Naphtho (2,1-b) (1,4) oxazine], 1- (4-methoxybenzyl) -3,3-dimethylspiro [indoline-2,3 ′-(3H) naphtho (2,1-b) ) (1,4) oxazine], 1- (2-methylbenzyl) -3,3-dimethylspiro [indoline-2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine] 1- (3,5-dimethylbenzyl) -3,3-dimethylspiro [indoline-2,3 ′-(3H) naphtho (2,1-b) (1,4) oxazine], 1- (4- Chlorobenzyl) -3,3-dimethylspiro [indoline-2,3′- 3H) naphtho (2,1-b) (1,4) include a compound having a spiro-oxazine structure, such as oxazine].

  Examples of the diarylethene compound include 1,2-bis (2-phenyl-4-trifluoromethylthiazole) -3,3,4,4,5,5-hexafluorocyclopentene, 1,2-bis (3- (2-Methyl-6- (2- (4-methoxyphenyl) ethynyl) benzothienyl))-3,3,4,4,5,5-hexafluorocyclopentene, 1,2-bis (5-methyl-2 -Phenylthiazol) -3,3,4,4,5,5-hexafluorocyclopentene, 1,2-bis (2-methoxy-5-phenyl-3-thienyl) -3,3,4,4,5 , 5-hexafluorocyclopentene, 1- (5-methoxy-1,2-dimethyl-3-indolyl) -2- (5-cyano-2,4-dimethyl-3-thienyl) -3,3,4,4 , 5,5-hex Such as fluoro cyclopentene and the like, 1,2 dithienylethenes compounds are preferred.

  Examples of the fulgide compound include N-cyanomethyl-6,7-dihydro-4-methyl-2-phenylspiro (5,6-benzo [b] thiophenedicarboximide-7,2′-tricyclo [3.3 1.1,7] decane], N-cyanomethyl-6,7-dihydro-2- (p-methoxyphenyl) -4-methylspiro (5,6-benzo [b] thiophenedicarboximide-7,2 ′ -Tricyclo [3.3.1.13,7] decane), 6,7-dihydro-N-methoxycarbonylmethyl-4-methyl-2-phenylspiro (5,6-benzo [b] thiophenedicarboximide- 7,2′-tricyclo [3.3.1.13,7] decane), 6,7-dihydro-4-methyl-2- (p-methylphenyl) -N-nitromethylspiro (5,6- Nzo [b] thiophenedicarboximide-7,2′-tricyclo [3.3.1.13,7] decane), N-cyanomethyl-6,7-dihydro-4-cyclopropyl-3-methylspiro (5 , 6-benzo [b] thiophenedicarboximide-7,2′-tricyclo [3.3.1.13,7] decane).

  Examples of the naphthopyran compound include 3,3-diphenyl-3H-naphtho (2,1-b) pyran, 2,2-diphenyl-2H-naphtho (1,2-b) pyran, and 3- (2- Fluorophenyl) -3- (4-methoxyphenyl) -3H-naphtho (2,1-b) pyran, 3- (2-methyl-4-methoxyphenyl) -3- (4-ethoxyphenyl) -3H-naphtho (2,1-b) pyran, 3- (2-furyl) -3- (2-fluorophenyl) -3H-naphtho (2,1-b) pyran, 3- (2-thienyl) -3- (2 -Fluoro-4-methoxyphenyl) -3H-naphtho (2,1-b) pyran, 3- [2- (1-methylpyrrolyl)]-3- (2-methyl-4-methoxyphenyl) -3H-naphtho 2,1-b) pyran, spiro [bicyclo (3 3.1) Nonane-9,3′-3H-naphtho (2,1-b) pyran], spiro [bicyclo (3.3.1) nonane-9-2′-3H-naphtho (2,1-b) ) Piran].

  Examples of the hexaaryl bisimidazole compound include pseudodogem-bis (diphenylimidazole) [2.2] paracyclophane, pseudodogem-bis (3,3′4,4′-tetramethoxydiphenylimidazole) [2.2]. Examples include paracyclophane.

<Photochromic compound-containing layer>
As described above, in the present invention, an embodiment in which a photochromic compound-containing layer (hereinafter also referred to as “photochromic resin layer”) is provided separately from the linearly polarizing plate or the retardation plate is one of preferred embodiments. .
As a method for forming the photochromic resin layer, as described above, a resin film containing a photochromic compound (hereinafter, also referred to as “photochromic compound-containing film”) is prepared and applied to the surface of the linearly polarizing plate in the circularly polarizing plate. And a method of directly forming a coating film of a resin composition containing a photochromic compound on the surface of the linearly polarizing plate in the circularly polarizing plate.
In the case where a coating film containing a photochromic compound is directly formed on the surface of the latter linear polarizing plate, the resin composition is formed on the surface of the linear polarizing plate so that the thickness after drying is about the thickness of the following film. Application and drying may be performed by a known method such as die coating or gravure coating.

<Photochromic compound-containing film>
Any photochromic compound-containing film can be used as long as the photochromic compound is dispersed in the film. The resin film is, for example, a method of forming a resin composition containing a photochromic compound by a conventional method, and a base film is immersed in a staining solution containing a photochromic compound, and the base film is impregnated with the photochromic compound It can manufacture by the method of making it. Usually, the former is preferable in that the content of the photochromic compound can be easily adjusted.

Film formation of the resin composition containing the photochromic compound can be performed by a conventional method. For example, a photochromic compound-containing film can be produced by a melt extrusion method, a coating method, or the like. In the latter case, for example, a resin resin composition containing a photochromic compound and a resin, preferably a resin solution in which both are dissolved, is applied to the surface of the release agent applied to the release agent film by die coating, After applying and drying using a known coating method such as gravure coating to form a coating film, a transparent film is laminated on the coating film as necessary, and a book with a release agent. A photochromic compound-containing film used in the invention can be produced.
As the resin used in the resin composition containing the photochromic compound, any resin can be used as long as it has good compatibility with the photochromic compound and the photochromic compound is appropriately dispersed in the resin. For example, resins such as acrylic resin, urethane resin, and PVA resin can be used. Usually, an acrylic resin is preferable from the viewpoint of durability and light transmission.
The resin composition containing the photochromic compound usually contains a solvent for adjusting the viscosity. The solvent in the resin composition is preferably a solvent that can dissolve the photochromic compound and the resin. For example, organic solvents, such as toluene and DMSO, and aqueous solvents, such as water or a mixed solution of water and a water-soluble organic solvent, are mentioned. Usually an organic solvent is preferred.

    The content ratio of the photochromic compound contained in the resin composition containing the photochromic compound is usually 0.1 to 20% by mass, preferably 0, based on the total amount of solid content of the resin composition (all components other than the solvent). 2-7% by mass, more preferably 0.2-5% by mass, and most preferably 0.3-4% by mass. If the content is too small, even if the photochromic compound is colored, the absorption characteristics of the polarizing element of the present invention do not change. When there is too much content, there exists a possibility of affecting the intensity | strength and adhesiveness of the resin film containing a photochromic compound.

As a method for producing a photochromic compound-containing film by dyeing, a base film may be dyed according to a conventionally known film dyeing method using a dyeing solution containing a photochromic compound as a dyeing solution. For example, it can be performed according to the dyeing method of the base film using the dichroic dye in the section of the linear polarizing plate. That is, according to the dyeing method of the linear polarizing plate, for example, using a polyvinyl alcohol-based resin film as a base film, performing a dyeing treatment using a dyeing solution containing a photochromic compound instead of a dichroic dye, stretching treatment, and A photochromic compound-containing film can be produced by performing each step of curing agent treatment with boric acid or the like. Either the dyeing process or the stretching process may be performed first or simultaneously. The stretching treatment may be performed simultaneously with the curing agent treatment. The curing agent treatment is usually performed simultaneously with the dyeing treatment and / or after the dyeing treatment.
The conditions for the dyeing process at this time are not particularly limited. The dyeing solution used for the dyeing treatment is obtained by dissolving the photochromic compound in water or an aqueous solution. The concentration of the dyeing solution at this time is preferably about 0.001 to 10% by mass, the immersion time of the base film is preferably about 20 seconds to 20 minutes, and the dyeing temperature is preferably about 20 ° C to 80 ° C.

The photochromic compound contained in the photochromic resin layer may have dichroism. In this case, the photochromic compound-containing film obtained by the above method or the like is stretched (preferably uniaxially stretched), whereby the photochromic compound can be oriented in one direction and dichroism can be imparted to the photochromic compound.
As a method for stretching the film, any known method such as a wet method or a dry method may be used. As for the draw ratio at this time, it is preferable that the total draw ratio is about 2 to 10 times with respect to the original film.
When producing a photochromic compound-containing film by a dyeing method, in any of the photochromic compound-containing film production steps described above, a step of stretching the substrate film (preferably uniaxial stretching) may be included, and the substrate film is stretched. The step may be performed before or after the step of impregnating the base film with the dyeing solution, or may be performed simultaneously.

When dichroism is imparted to a photochromic compound, the photochromic compound having a long chain structure with different molecular structures in length and breadth, and more preferably, π conjugation such as a benzene ring and a heterocycle spreads and connected by π conjugation A photochromic compound in which the three-dimensional structure between the skeletons does not change (however, the three-dimensional structure can change when it changes to any state during coloring or fading) is preferred in terms of orientation. As such a compound, any of the above spiropyran compounds, spirooxazine compounds, diarylethene compounds, fulgide compounds and naphthopyran compounds can be preferably used.
When dichroism is imparted to the photochromic compound, the photochromic compound-containing film and the circularly polarizing plate are laminated so that the absorption axis of the photochromic compound-containing film is parallel to the absorption axis of the linear polarizing plate. By laminating in this way, the colored photochromic compound-containing film and the high-transmittance polarizing plate work together in an environment with strong ultraviolet rays to work as a linear polarizing plate with excellent polarizing performance, and an excellent antireflection function. It can be demonstrated.

  By sticking the photochromic compound-containing film obtained by the above method or the like to a circularly polarizing plate comprising the linearly polarizing plate and the retardation plate via an adhesive or the like, it is the polarizing element for OLED of the present invention. A circularly polarizing plate with a photochromic resin layer is obtained. What is necessary is just to use the well-known adhesive used for an optical member as an adhesive at this time.

  In the photochromic resin layer in the polarizing element of the present invention, a coating film of a resin composition containing a photochromic compound may be directly formed on the linearly polarizing plate side of the circularly polarizing plate of the present invention. The formation of the coating film at this time may be performed according to the method of forming a coating film on a transparent film using the resin solution containing at least the photochromic compound and the resin.

The position of the photochromic resin layer of the present invention is not particularly limited as long as the photochromic compound can absorb ultraviolet rays contained in external light. However, since it can efficiently absorb ultraviolet rays, the emission side of the linearly polarizing plate. It is preferable to arrange on the observer side, the side on which external light is incident.
The content ratio of the photochromic compound in the photochromic resin layer of the present invention is usually about 0.1 to 10% by mass, preferably 0.2 to 7% by mass, more preferably 0, based on the total amount of the resin layer. 2 to 5% by mass, most preferably 0.3 to 4% by mass. Further, when the resin layer is used in the polarizing element for OLED of the present invention, the photochromic compound concentration in the resin layer is such that the light transmittance of 550 nm of the polarizing element for OLED of the present invention in which the resin layer is laminated is ultraviolet light. In the absence of the resin layer, the light transmittance of the circularly polarizing plate without the resin layer is usually about 1 to 7%, preferably about 2 to 5%, more preferably 2 to 4%. This is the concentration that gives the value.
If the content is too small, even if the photochromic compound is colored, the absorption characteristics of the polarizing element of the present invention do not change. If the content is too large, the strength and adhesiveness of the photochromic resin layer may be affected.
Although the thickness of the photochromic resin layer of this invention is not specifically limited, About 10 micrometers-about 100 micrometers are preferable.

<Photochromic compound and dichroic dye-containing polarizing plate>
In the polarizing element for OLED of the present invention, the linear polarizing plate may be a linear polarizing plate containing a photochromic compound together with a dichroic dye (hereinafter also referred to as “photochromic compound-containing polarizing plate”).
The method for producing the photochromic compound-containing polarizing plate of the present invention is not particularly limited as long as it can appropriately contain a dichroic dye and a photochromic compound in the base film of the linear polarizing plate. For example, using a dyeing solution containing both a dichroic dye and a photochromic compound as a dyeing solution, the substrate film is dyed according to a conventionally known film dyeing method, or dyeing with the dichroic dye is used. Separately, by using a photochromic compound-containing staining solution and dyeing with a photochromic compound, a linearly polarizing element film containing both may be produced.
More specifically, in the method of linearly polarizing plate by dyeing a base film using the dichroic dye, for example, instead of using a dichroic dye alone with a polyvinyl alcohol-based resin film as the base film, Dyeing treatment is performed using a dye solution containing both the dichroic dye and the photochromic compound, or separately from the dyeing with the dichroic dye, the photochromic compound-containing dye solution is used, It is possible to produce a linearly polarizing element film containing both the dichroic dye and the photochromic compound by performing dyeing, stretching treatment, and curing agent treatment with boric acid or the like performed as necessary. it can.
Either the dyeing process or the stretching process may be performed first or simultaneously. The stretching treatment may be performed simultaneously with the curing agent treatment. The curing agent treatment is usually performed simultaneously with the dyeing treatment and / or after the dyeing treatment.
The conditions for the dyeing process at this time are not particularly limited. The dyeing solution used for the dyeing treatment is obtained by dissolving both the dichroic dye and the photochromic compound in water or an aqueous solution. Moreover, you may dye with a photochromic compound separately from the dyeing | staining of the said dichroic dye.
At this time, the concentration of the photochromic compound in the staining solution varies depending on the staining conditions, and thus cannot be generally stated. However, the preferable concentration of the photochromic compound is about 0.01 to 10 g / L with respect to the total amount of the staining solution. The immersion time of the base film is preferably about 20 seconds to 20 minutes, and the dyeing temperature is preferably about 20 ° C to 80 ° C.
The concentration of the photochromic compound in the linearly polarizing element film is such that the light transmittance at 550 nm of the polarizing element for OLED of the present invention using the linearly polarizing element film is a straight line that does not contain a photochromic compound when there is no ultraviolet light. Concentration which is a low value within a range of usually about 1 to 7%, preferably about 2 to 6%, more preferably 2 to 5% of the transmittance of light at 550 nm of a circularly polarizing plate using a polarizing element film. It is.
The obtained polarizing element film can be made into a linearly polarizing plate by a conventional method with a protective film or the like.

The above method can be used when the photochromic compound is water-soluble, but many photochromic compounds are water-insoluble. Therefore, the casting method which forms a coating film normally using a photochromic compound containing resin solution is used. For example, a resin solution containing a polyvinyl alcohol-based resin and a photochromic compound is coated on a base film, for example, a polyethylene terephthalate film, dried to form a coating film, and then the film peeled off from the base material has two colors. By using a dyeing solution containing a functional dye, a dyeing treatment is performed according to a conventionally known film dyeing method, a stretching treatment, and a curing agent treatment with boric acid or the like, which is performed as necessary, to obtain a photochromic compound and A dichroic dye-containing elemental film can be obtained, and a protective film can be attached thereto to form a polarizing plate.
Either the dyeing process or the stretching process may be performed first or simultaneously. The stretching treatment may be performed simultaneously with the curing agent treatment. The curing agent treatment is usually performed simultaneously with the dyeing treatment and / or after the dyeing treatment.

In the manufacturing method of said photochromic compound containing linearly polarizing plate, the process of extending | stretching a base film is included, and since a photochromic compound is orientated with a dichroic dye in one direction, dichroism is provided to the photochromic compound. The When the photochromic compound has dichroism, the resulting photochromic compound-containing linear polarizing plate functions as the above-described high-transmittance polarizing plate in an environment where the external light is weak, and in an environment where the external light is strong, the photochromic compound is Colored and functions as a linear polarizing plate with high polarization performance.
As the photochromic compound at this time, compounds listed as photochromic compounds that can be preferably used when imparting dichroism to the photochromic compound can be preferably used.
The OLED polarizing element of the present invention is obtained by laminating the retardation plate to the photochromic compound-containing polarizing plate. The polarizing element for OLED of the present invention exhibits an excellent antireflection function because the photochromic compound is colored to exhibit dichroism and functions as a linear polarizing plate with excellent polarization performance in an environment with strong external light. To do. Also, in an indoor environment where the outside light is weak, the photochromic compound is not colored and is almost the same as the linear polarizing plate using only the dichroic dye, so that it has a certain reflection function and is also visible in the room. Retained.

<OLED polarizing element>
The polarizing element for OLED of the present invention is obtained by using a linearly polarizing element film containing a dichroic dye and a photochromic compound in combination. More specifically, a photochromic compound-containing layer is laminated on the circularly polarizing plate comprising the linearly polarizing plate having the linearly polarizing element film containing the dichroic dye and the λ / 4 retardation plate obtained above. Alternatively, the OLED polarizing element of the present invention can be obtained by laminating a linearly polarizing plate having a polarizing element film containing a photochromic compound together with the dichroic dye and a λ / 4 retardation plate. .
The polarizing element of the present invention may include an optical layer other than the linearly polarizing plate, the retardation plate, and the photochromic resin layer as long as the antireflection function and the visibility improving effect of the polarizing element are not impaired. For example, the polarizing element of the present invention may include a protective layer (hard coat layer), an AR layer (antireflection layer), another retardation plate, a color filter, and the like described in the section of the polarizing plate.
The positive photochromic compound contained in the polarizing element of the present invention is colored by absorbing ultraviolet rays contained in sunlight or ultraviolet rays of various lamps such as ultraviolet lamps, mercury lamps, xenon lamps, and the like, and visible light and / or heat. To fade. Since the coloring and decoloring of the photochromic compound is reversible, the photochromic compound is colored when the action of ultraviolet rays is greater than that of visible light and / or heat, and moreover, the action of visible light and / or heat is more than the action of ultraviolet rays. Discolor when large. As a photochromic compound used by this invention, the positive photochromic compound colored with the ultraviolet-ray whose wavelength is about 250-400 nm is preferable.

  Various additives such as a stabilizer, an antioxidant, an antistatic agent, and a plasticizer may be added to each optical layer of the polarizing element for OLED of the present invention as necessary.

  Although the polarizing element for OLED of the present invention depends on the purpose of use, the transmittance of emitted light from the OLED at the time of coloring the photochromic compound is about 5-55%, more preferably about 10-45%, In addition, the reflectance of external light by the cathode electrode of the OLED is preferably about 10% or less, more preferably about 6% or less.

Preferred embodiments of the polarizing element for OLED of the present invention include the following embodiments (I) to (III).
(I) On the linearly polarizing plate in the circularly polarizing plate comprising the linearly polarizing plate and the λ / 4 retardation plate containing the dichroic dye (on the surface opposite to the surface on which the λ / 4 retardation plate is laminated), The polarizing element for OLED by which the resin film containing a photochromic compound was laminated | stacked.
(II) On a linearly polarizing plate (on the opposite side of the surface on which the λ / 4 retardation plate is laminated) in a circularly polarizing plate comprising a linearly polarizing plate containing a dichroic dye and a λ / 4 retardation plate, and A polarizing film for OLED, in which a resin film containing an oriented photochromic compound having dichroism is laminated so that the absorption axis of the resin film and the absorption axis of a linearly polarizing plate are parallel when the photochromic compound is colored element.
(III) A polarizing element for OLED having a linearly polarizing plate containing both the dichroic dye and the photochromic compound and a λ / 4 retardation plate.

  From the viewpoint of preventing deterioration of the dichroic dye contained in the polarizing plate, in the polarizing element for OLED of the present invention, the photochromic resin layer is on a linear polarizing plate of a circularly polarizing plate (λ / 4 retardation plate is laminated). It is preferable that it is provided on the opposite surface). By providing a photochromic resin layer containing a photochromic compound on the side of the polarizing plate where external light is incident, an ultraviolet absorber can be added to the transparent protective film of the polarizing plate, and the dichroic dye contained in the polarizing plate This is because the polarization ability can be prevented from being deteriorated by ultraviolet rays.

<Organic EL display device>
The organic EL display device of the present invention (hereinafter also referred to as an OLED display device) has an OLED and the polarizing element for OLED of the present invention. Specifically, the present invention is provided by providing the OLED polarizing element of the present invention so that the light emitting surface (image display surface) of the OLED (organic EL element) faces the phase difference plate side of the OLED polarizing element of the present invention. OLED display device is obtained. The characteristics of the organic EL display device of the present invention will be described below with reference to the drawings.
An example of a schematic view of the structure of an organic EL display device comprising the polarizing element for OLED of the present invention is shown in FIG. In FIG. 1, 1 is a photochromic layer, 2 is a linear polarizing plate, 3 is a phase difference plate (quarter wavelength plate), and 4 is an OLED. In FIG. 1, an optical layer that is provided as necessary with little involvement in light absorption and reflection is omitted.

  According to the polarizing element of the present invention, external light including strong ultraviolet rays passes through both the photochromic layer and the circularly polarizing plate twice, and the external light is blocked, so that only a small amount of light reaches the display screen. Thus, it is possible to effectively block outside light. On the other hand, since the light emitted from the OLED (display light) reaches the display screen only once through the circularly polarizing plate and the photochromic layer, the amount blocked by the photochromic layer is remarkably small compared to the outside light. The ratio (contrast) of the display light amount to the reflected light amount of external light on the screen can be significantly increased.

  On the other hand, since the amount of ultraviolet rays is small in the room and the photochromic compound is decolored, it does not play a role in reducing the reflected light in the room. Similarly, the used OLED display device can ensure visibility in the room.

  The organic EL display device provided with the circularly polarizing plate with a photochromic layer of the present invention is used for any application, and in particular, is often used outdoors, such as notebook computers, tablet computers, mobile phones, and the like. It can be preferably used for portable devices such as portable game machines, video cameras, monitors for car navigation systems, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited only to the following Example.
The transmittance of the polarizing plate was measured as follows. The transmittance when one polarizing plate is used is the single transmittance Ys, and the transmittance when the two polarizing plates are stacked so that the absorption axes are orthogonal to each other is defined as the orthogonal transmittance Yc. Each transmittance was calculated by the following formula (1) by obtaining a spectral transmittance τλ every predetermined wavelength interval dλ (here, 10 nm) in a wavelength region of 380 to 700 nm.

In the equation, Pλ represents a spectral distribution of standard light (C light source), and yλ represents a 2 ° visual field color matching function. Spectral transmittance τλ was measured using a spectrophotometer (manufactured by Hitachi, Ltd., product name U-4100).

Example 1
(1) Production of high transmittance linear polarizing plate A polyvinyl alcohol resin film (manufactured by Kuraray Co., Ltd., VF-PS, thickness 75 μm) was washed with water and then swollen in water at 35 ° C. As a dichroic dye, Orange dichroic dye (λmax = 460 nm, dichroic ratio 39.4) is 0.105 g / L [mass / volume], Red dichroic dye (λmax = 520 nm, dichroic) 38.8) 0.062 g / L [mass / volume], Blue dichroic dye (λmax = 600 nm, dichroism ratio 40.8) 0.19 g / L [mass / volume], Green System dichroic dye (λmax = 660 nm, dichroic ratio 29.7), 0.10 g / L [mass / volume], respectively, and mirabilite and sodium tripolyphosphate each 0.25 g / L The swollen film was immersed in the contained 46 ° C. dyeing solution for 2 minutes to carry out dye dyeing treatment. The dyed film is washed in a 2.6% by mass boric acid aqueous solution and then uniaxially stretched in a 3.7% by mass boric acid aqueous solution at 54 ° C. so that the draw ratio is 6.2 times. The dichroic dye in the film was oriented. The obtained stretched film was washed with water at 25 ° C. and then dried in air at 60 ° C. to obtain a polarizing element film. The thickness of the obtained polarizing element film was 23 μm. When the boric acid concentration in the polarizing element film was determined by neutralization titration, the boric acid content in the polarizing element film was 17.0% by mass.
A TAC film having a thickness of 80 μm (manufactured by FUJIFILM Corporation) is laminated on both surfaces of the obtained polarizing element film using a polyvinyl alcohol-based adhesive, and then dried at 70 ° C. to obtain a high transmittance linear polarizing plate of the present invention Was made.
Regarding the transmittance in the wavelength region of 380 to 700 nm of the obtained polarizing plate, the single transmittance was 50.29% and the orthogonal transmittance was 9.92%.

(2) Production of circularly polarizing plate To the obtained high transmittance polarizing plate, a quarter-wave retardation plate made of polycarbonate (Pure Ace WR manufactured by Teijin Ltd.) was added to the absorption axis of the polarizing plate and the retardation of the retardation plate. Bonding was performed using an adhesive (trade name: SK Dyne SK-1885, manufactured by Soken Chemical Co., Ltd.) so that the angle with the phase axis was 45 degrees, and a high transmittance circularly polarizing plate of the present invention was produced. .

で表されるスピロピラン系化合物（１，３，３−トリメチルインドリノ−６’−ニトロベンゾピリロスピラン、東京化成工業株式会社製）を２．７質量％含有するトルエン溶液に、アクリル樹脂溶液（不揮発分１９質量％）を、溶液の不揮発分の総量が１５質量％になるように加えた。ここで、式（Ｉ）で表される化合物は、紫外線の照射により左辺の化合物から右辺の化合物に分子構造が変化し、着色する。可視光又は熱により右辺の化合物は元の左辺の化合物に戻り、脱色する。式（Ｉ）の右辺の化合物の可視光領域における最大吸収波長は５４８ｎｍである。
離型剤付きＰＥＴフィルム（リンテック株式会社製、商品名ＰＥＴ５０１１）の離型剤が付着している面の上に、上記で得られたフォトクロミック溶液を厚みが均一になるように展開し、乾燥機にて７０℃で３分間乾燥した。このときのフォトクロミック層における上記式（Ｉ）の化合物の濃度は０．４８質量％であり、フォトクロミック層の膜厚は３０μｍであった。得られたフィルムのフォトクロミック層側に膜厚２５μｍのＰＥＴフィルム（東洋紡績株式会社製、商品名Ｅ５１０１）を積層して、フォトクロミック化合物含有フィルムを作製した。
（４）本発明の偏光素子の作製
上記で得られたフォトクロミック層付きフィルムから離型フィルムを剥がし、フォトクロミック層付きフィルムのフォトクロミック層側と、前記高透過率円偏光板の直線偏光板側が向かい合うよう、粘着剤（綜研化学株式会社製、商品名ＳＫダイン ＳＫ−１８８５）を用いて積層し、本発明の偏光素子（フォトクロミック層付き円偏光板）を得た。 (3) Production of photochromic-containing film Formula (I) below:

In a toluene solution containing 2.7% by mass of a spiropyran-based compound (1,3,3-trimethylindolino-6′-nitrobenzopyrospirane, manufactured by Tokyo Chemical Industry Co., Ltd.), an acrylic resin solution ( Non-volatile content 19% by mass) was added so that the total non-volatile content of the solution was 15% by mass. Here, the compound represented by the formula (I) is colored by changing the molecular structure from the compound on the left side to the compound on the right side by irradiation with ultraviolet rays. Visible light or heat causes the right side compound to return to the original left side compound and decolorize. The maximum absorption wavelength in the visible light region of the compound on the right side of the formula (I) is 548 nm.
On the surface of the PET film with a release agent (trade name PET5011, manufactured by Lintec Corporation) on which the release agent is attached, the photochromic solution obtained above is spread so as to have a uniform thickness, and is dried. And dried at 70 ° C. for 3 minutes. At this time, the concentration of the compound of the above formula (I) in the photochromic layer was 0.48% by mass, and the film thickness of the photochromic layer was 30 μm. A PET film (trade name E5101, manufactured by Toyobo Co., Ltd.) having a film thickness of 25 μm was laminated on the photochromic layer side of the obtained film to prepare a photochromic compound-containing film.
(4) Production of polarizing element of the present invention The release film is peeled off from the film with photochromic layer obtained above so that the photochromic layer side of the film with photochromic layer faces the linearly polarizing plate side of the high transmittance circularly polarizing plate. And a pressure-sensitive adhesive (trade name: SK Dyne SK-1885, manufactured by Soken Chemical Co., Ltd.) to obtain a polarizing element (circular polarizing plate with a photochromic layer) of the present invention.

Example 2
The polarizing element of the present invention is the same as Example 1 except that the concentration of the compound represented by Formula (I) in the photochromic layer is 3.90% by mass in Example 3 (3). (A circularly polarizing plate with a photochromic layer) was obtained.

Test example 1 (UV irradiation test)
When the circularly polarizing plate with the photochromic layer obtained in Examples 1 and 2 above was irradiated with ultraviolet rays having a wavelength of 352 nm and an intensity of 1.2 mW / cm ² for 10 seconds using an ultraviolet lamp, coloring of the photochromic layer was confirmed. It was. The ultraviolet intensity of 1.2 mW / cm ² is about the same as the ultraviolet intensity measured at a window in a room where direct sunlight does not shine on a clear day. Thus, it was found that the photochromic layer-attached circularly polarizing plate of the present invention obtained in the Examples has sufficient sensitivity to color under conditions of strong external light such as outdoors.

Test Example 2 (Measurement of transmittance and reflectance)
About the circularly-polarizing plate with a photochromic layer obtained in the said Example 1 and 2, the transmittance | permeability and reflectance before and behind an irradiation test were measured with the spectrophotometer (The Hitachi High-Technologies Corporation make, product name U-4100). The transmittance and reflectance of the high transmittance circularly polarizing plate obtained in Example 1 were also measured in the same manner.
Here, the transmittance was measured for the transmittance of light having a wavelength of 550 nm measured when one polarizing element was used. In the circularly polarizing plate of Example 1, the reflectance was measured from the linearly polarizing plate side, and in the circularly polarizing plates with the photochromic layers of Examples 1 and 2, the measurement light was incident from the side of the photochromic layer and transmitted from the phase difference plate side. The reflectance of 550 nm light was measured when all of the transmitted light was reflected and again incident on the phase difference plate side and again emitted from the linear polarizing plate side or the photochromic layer side.
The measurement results are shown in Table 1 below.

注：参考例は実施例１の（２）で作製した円偏光板を使用した。

Note: For the reference example, the circularly polarizing plate produced in Example 1 (2) was used.

  As is clear from Table 1 above, the high-transmittance linearly polarizing plate of the present invention and the circularly polarizing plate with a photochromic layer of the present invention have a certain degree of anti-reflection function in an environment with weak external light (low ultraviolet rays). And since it has the high transmittance | permeability, it turned out that the emitted light from OLED can be increased compared with the conventional circularly-polarizing plate. Further, in an environment with strong external light (a lot of ultraviolet rays), the circularly polarizing plate with a photochromic layer of the present invention has both transmittance and reflectance decreased due to coloring of the photochromic compound, but the decrease in reflectance is the transmittance Since the reduction was remarkable, the ratio of the transmittance to the reflectance was improved. For example, in the circularly polarizing plate with the photochromic layer of Example 2, the ratio of the transmittance to the reflectance before the ultraviolet irradiation is about 4.4 times, whereas the ratio of the transmittance to the reflectance after the ultraviolet irradiation is about 11 .I improved to 1 times. Therefore, it was suggested that the polarizing element for OLED of the present invention can improve the contrast ratio of the emitted light from the OLED to the reflected light of the external light in an environment with strong external light.

Test Example 3 (OLED contrast ratio evaluation)
From the measurement results of Test Example 2, the OLED display with the polarizing element of the present invention, the contrast ratio of the light emitted from the OLED to the reflection light (Lr) in the ambient light 1000 cd / ^{m 2} and 5000cd / ^{m 2} (Le) (CR) was evaluated.
CR was calculated by the following formula.
CR = Le / Lr = (Leo × T) / (La × Yr × R)
The definition of each parameter in the formula and the substituted values are shown in Table 2 below.

For the values of T and R in Examples 1 and 2, the transmittance and reflectance after the ultraviolet irradiation test were substituted.
Table 3 below shows the CR evaluation results of each polarizing element calculated by the above formula.

  As apparent from Table 3 above, the circularly polarizing plate with a photochromic layer of the present invention is a light emitted from an OLED with respect to reflected light in proportion to the concentration of the photochromic compound in the photochromic layer by coloring the photochromic compound by irradiation with ultraviolet rays. It was confirmed that the contrast ratio (CR) was improved and the visibility of the display screen was improved.

DESCRIPTION OF SYMBOLS 1 ... Photochromic layer, 2 ... Linear polarizing plate, 3 ... Retardation plate (1/4 wavelength plate), 4 ... Organic EL element (OLED)

Claims (14)

A polarizing element for an organic EL display device using a photochromic compound in combination with a polarizing element film containing a dichroic dye other than a photochromic compound (excluding iodine) ,
The polarizing element for an organic EL display device is a circularly polarizing plate comprising a linearly polarizing plate having a polarizing element film containing one or more dichroic dyes other than a photochromic compound and a λ / 4 retardation plate. A polarizing element for an organic EL display device in which a photochromic compound-containing layer is laminated, or a linear polarizing plate having a polarizing element film containing a photochromic compound together with the dichroic dye and a λ / 4 retardation plate are laminated .   The polarizing element for an organic EL display device according to claim 1, wherein the linear polarizing plate has a single transmittance in visible light of greater than 42% and 70% or less.   The polarizing element for organic EL display devices according to claim 1, wherein the linear polarizing plate has an orthogonal transmittance of 0.1 to 20% in visible light.   4. The polarizing element for an organic EL display device according to claim 1, wherein a hue of the linearly polarizing plate is neutral gray. The polarizing element film is
Below (1)-(3)
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) a dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and
(3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less,
The polarizing element for organic EL display devices according to any one of claims 1 to 4, which is a polarizing element film containing at least two dyes selected from the dyes.   Dichroic dyes other than photochromic compounds contained in the polarizing element film are orange dichroic dyes, red dichroic dyes, blue dichroic dyes, and green dichroic dyes. The polarizing element for organic EL display apparatuses as described in any one of Claims 1-5 which is a dichroic dye chosen from the group which consists of.   Dichroic dyes other than photochromic compounds contained in the polarizing element film are orange dichroic dyes, red dichroic dyes, blue dichroic dyes, and green dichroic dyes. The polarizing element for organic EL display devices according to claim 6, which is a dichroic dye containing each of the above.   The polarizing element for organic EL display devices according to any one of claims 1 to 7, wherein the photochromic compound is a compound that is colored by ultraviolet light and decolored by visible light or heat.   The polarizing element for organic EL display devices according to any one of claims 1 to 8, wherein the photochromic compound is a spiropyran compound having a spiropyran structure in which a pyran ring is spiro-condensed.   The concentration of the photochromic compound in the photochromic compound-containing layer is 0.1 to 20% by mass relative to the total amount of the containing layer, or in a linearly polarizing element film containing both the dichroic dye and the photochromic compound 10. The polarizing element for an organic EL display device according to claim 1, wherein the concentration of the photochromic compound is from 0.1 to 50 mass% with respect to the total amount of the linear polarizing element film.   The polarizing element for organic EL display devices according to any one of claims 1 to 10, wherein the photochromic compound is oriented in the same direction as the polarization direction of the laminated linearly polarizing plate in the photochromic compound-containing layer.   The orthogonal transmittance in visible light in the linear polarizing plate is 0.1 to 20%, the single transmittance is greater than 42% and 70% or less, and the hue is neutral gray. The linearly-polarizing plate for polarizing elements for organic electroluminescent displays as described in any one. As a dichroic dye (except iodine)
Below (1)-(3)
(1) a dichroic dye having a maximum absorption wavelength (λmax) at 400 nm or more and less than 500 nm,
(2) a dichroic dye having a maximum absorption wavelength (λmax) at 500 nm or more and less than 600 nm, and
(3) a dichroic dye having a maximum absorption wavelength (λmax) at 600 nm or more and 700 nm or less,
The linearly polarizing plate for an organic EL display device according to claim 12, comprising at least two dyes selected from the dyes.   The organic electroluminescence display which has a polarizing element for organic electroluminescence displays as described in any one of Claims 1-11.

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