Optical system and optical device having the same

Abstract

The present invention relates to an optical system, which comprises a polarized light emitting element and a filter, wherein the polarized light emitting element absorbs light of a wavelength different from at least a part of the wavelength of the emitted light, has an axial absorption anisotropy with different light absorption amounts, and can emit polarized light in the visible light region by absorbing light; the filter has an absorption light correction monomer transmittance of 45 to 100%, and can absorb light in the visible light region; and the optical system satisfies the relationship of formula (1) or formula (2). em‑L‑λmax ×F em‑L <0.6×A fi‑em‑λmax <0.35 Formula (1). 0 <TAF em‑L <0.7×TA fi‑em Formula (2).

Description

Technical Field

[0001] The present invention relates to an optical system and a display device (display) having the optical system, wherein the optical system emits high-brightness polarized light. Background Art

[0002] Polarizing plates with light penetration or shielding functions, liquid crystals with light switching functions, and liquid crystal displays (LCDs) are basic components of display devices. The application field of LCDs has gradually expanded from small machines such as electronic computers and clocks that were initially sold on the market to notebook computers, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, indoor and outdoor information display devices, measuring instruments, etc. In addition, polarizing plates can also be applied to lenses with polarizing functions, and are used in sunglasses with improved visibility, and polarized glasses corresponding to 3D televisions in recent years, etc., and are used in portable information terminals headed by wearable terminals, and are partially practical. The uses of polarizing plates cover a wide range, and the environment in which they are used also covers a wide range of conditions from low temperature to high temperature, low humidity to high humidity, and low light intensity to high light intensity, so polarizing plates with high polarization performance and excellent durability are sought.

[0003] Generally speaking, the polarizing film constituting the polarizing plate can be manufactured by dyeing the film substrate of polyvinyl alcohol or its derivatives (or making the aforementioned substrate contain the aforementioned dye, etc.) with iodine or dichroic dyes, and stretching and orienting it; or, it can be manufactured by dehydrating the polyvinyl chloride film with hydrochloric acid or dehydrating the polyvinyl alcohol film to generate polyene and orienting it. The polarizing plate composed of such a well-known polarizing film generally uses dichroic pigments that have absorption in the visible light region, so the transmittance is reduced. For example, the transmittance of the general polarizing plate sold on the market is 35 to 45%.

[0004] In addition, as for the "polarization degree", which is one of the indicators showing the polarization performance of the polarizing plate, in order to show 100% polarization degree, when there are x-axis and y-axis light in a two-dimensional plane, only one-axis light must be absorbed. Therefore, in order to absorb only one-axis light, a general polarizing plate uses iodine or a dichroic dye. When only one-axis light is absorbed, the amount of light that theoretically penetrates the polarizing plate becomes less than 50% relative to 100% of the incident light. In addition, due to the decrease in polarization degree caused by poor orientation of iodine or dichroic dyes, the light loss caused by the film medium, the interface reflection of the film surface, etc., the actual transmittance is lower than 50%, and as a result, the transmittance of the well-known polarizing plate is as low as 35 to 45%. In response to the problem that the transmittance of such a general polarizing plate is as low as 35 to 45%, a technology of a polarizing plate for ultraviolet light has been described in Patent Document 1, which maintains a certain degree of transmittance in the visible light region while exerting a polarizing function. However, although the polarizing plate obtained by this technology has high transmittance, it does not provide a high degree of polarization in the entire visible light region and can only be used in a device that displays images using light around 400 nm.

[0005] If a polarizing plate with low transmittance of light in the visible light region or a polarizing plate with low polarization degree is used in, for example, a display, the overall brightness or contrast of the display will be reduced. In order to solve this problem, a method of obtaining polarized light without using a well-known polarizing plate has been studied, and as for one of the methods, an element that emits polarized light (polarized light emitting element) has been described in Patent Documents 2 to 6.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] [Patent Document 1] WO2005 / 01527

[0009] [Patent Document 2] Japanese Patent Application Publication No. 2008-224854

[0010] [Patent Document 3] Japanese Patent Application Publication No. 2013-121921

[0011] [Patent Document 4] WO2011 / 111607

[0012] [Patent Document 5] U.S. Patent No. 3,276,316

[0013] [Patent Document 6] Japanese Patent Application Laid-Open No. 4-226162

[0014] [Patent Document 7] WO2014 / 162635

[0015] [Patent document 8] WO2007 / 138980 publication.

[0016] [Non-patent literature]

[0017] [Non-patent document 1] "Application of functional pigments", CMC Co., Ltd., 1st edition, supervised by Masahiro Irie, pp. 98 to 100. Summary of the invention

[0018] [Problems to be solved by the invention]

[0019] However, the polarized light emitting elements described in patent documents 2 to 4 use special metals, such as rare and expensive metals such as lanthanide elements headed by europium, so the manufacturing cost is high, and the manufacturing is difficult and not suitable for mass production. In addition, these polarized light emitting elements are difficult to use in displays because of their low polarization degree, and it is difficult to obtain linearly polarized light. In addition, since only circularly polarized light of a specific wavelength is obtained, the use is limited. For example, even if it is used in a display, there are problems such as low brightness and contrast, and difficulty in designing a liquid crystal unit. Therefore, it is strongly expected to develop a novel polarizing plate that displays polarized light, and its polarized light luminance is high, and the transmittance in the visible light region is high, and it can also be applied to liquid crystal displays that require durability in harsh environments, and the materials using the polarizing plate. On the other hand, Japanese patent documents 5 or 6 disclose a polarized element that emits polarized light by irradiating ultraviolet rays. However, the polarization degree and brightness of the luminous element are obviously low, and the contrast of each axis of the so-called polarized light is low, so it is not sufficient to use it in displays, and its light resistance is also low.

[0020] The object of the present invention is to provide an optical system having a polarized light emitting effect, a high degree of polarization, and a high contrast. In addition, another arbitrary object of the present invention is to provide an optical system having high transparency. In addition, another arbitrary object of the present invention is to provide a display device using the optical system.

[0021] [Methods to solve the problem]

[0022] The inventors of the present invention have devoted themselves to research to achieve the above-mentioned purpose, and as a result, have discovered an optical system comprising a polarized light-emitting element and a filter, wherein the wavelength of the light absorbed by the polarized light-emitting element is different from at least a part of the wavelength of the light emitted, and has axes with different light absorption amounts, and can emit polarized light in the visible light region by absorbing light; the filter is a light intensity-corrected (also called visual sensitivity-corrected) single-unit transmittance of 45 to 100%, and can absorb light in the visible light region; in addition, the optical system in which the polarized light-emitting element and the filter have a specific relationship can provide polarized light with high transparency and high contrast.

[0023] That is, the present invention is related to the following, but is not limited thereto.

[0024] [Invention 1] An optical system comprising a polarized light emitting element and a filter, wherein:

[0025] The polarized light emitting element absorbs light of a wavelength different from at least a portion of the wavelength of the light emitted, has axial absorption anisotropy with different amounts of light absorption, and can emit polarized light in the visible light region by absorbing light;

[0026] The filter is a light-corrected single-unit with a transmittance of 45 to 100% and can absorb light in the visible light region; and

[0027] The aforementioned optical system satisfies the relationship of formula (1) or formula (2):

[0028] A em-L-λmax ×F em-L <0.6×A fi-em-λmax <0.35 Formula (1)

[0029] In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A fi-em-λmax Indicates the absorbance of the filter at the maximum emission wavelength of the polarized light emitting element.

[0030] 0 <TAF em-L <0.7×TA fi-em Formula (2)

[0031] Where, TA fi-em TAF is the value obtained by integrating the absorbance of each wavelength of the filter in the wavelength range where the polarized light emitting element emits light. em-L It represents the value obtained by integrating the absorbance at each wavelength on the axis where the light absorption of the polarized light emitting element is the lowest and the quantum yield on the axis where the light absorption of the polarized light emitting element is the lowest in the light absorption wavelength range of the aforementioned polarized light emitting element.

[0032] [Invention 2] The optical system as described in Invention 1 at least satisfies the above-mentioned formula (2).

[0033] [Invention 3] An optical system as described in Invention 1 or 2, wherein the transmittance of the light intensity correction unit of the aforementioned filter is 50 to 99.9%.

[0034] [Invention 4] An optical system as described in any one of Inventions 1 to 3, wherein the filter is a polarizing element satisfying formula (3):

[0035] A em-L-λmax ×F em-L <0.6×APol-Kz-em-L-λmax <0.7 Formula (3)

[0036] In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A Pol-Kz-em-L-λmax It indicates the absorbance of the polarizing element at the highest absorption axis at the wavelength with the maximum emission along the axis where the emission amount of the polarizing element is the weakest.

[0037] [Invention 5] An optical system as described in any one of Inventions 1 to 4, wherein the filter is a polarizing element that satisfies formula (4):

[0038] 0 <TAF em-L <0.7×TA pol-Kz-em Formula (4)

[0039] Where, TA pol-Kz-em TAF is the value obtained by integrating the absorbance of each wavelength of the polarizing element at the highest absorption axis in the wavelength range in which the polarizing element emits light. em-L The expression is the same as that of formula (2).

[0040] [Invention 6] An optical system as described in any one of Inventions 1 to 5, wherein the filter is a polarizing element, and the polarizing element and the filter are provided in such a manner that an axis along which the light emission of the polarizing element is weakest is parallel to an axis along which the absorbance of the polarizing element is high.

[0041] [Invention 7] An optical system as described in any one of Inventions 1 to 6, wherein the hue of the filter is -5 ＊ <+3 and b ＊ <±3.

[0042] [Invention 8] An optical system as described in any one of Inventions 1 to 7, wherein the polarized light-emitting element contains a polarized light-emitting pigment, and the polarized light-emitting pigment is oriented.

[0043] [Invention 9] An optical system as described in any one of Inventions 1 to 8, wherein the polarized light emitting element emits polarized light by absorbing light in the ultraviolet region to the near-ultraviolet visible light region.

[0044] [Invention 10] An optical system as described in any one of Inventions 1 to 9, wherein the polarized light-emitting element has a maximum absorption wavelength of light in the ultraviolet region to the near-ultraviolet visible light region.

[0045] [Invention 11] An optical system as described in any one of Inventions 1 to 10, which is a stack of the aforementioned polarized light-emitting element and the aforementioned filter.​

[0046] [Invention 12] An optical system as described in any one of Inventions 1 to 11, which includes a phase difference plate.

[0047] [Invention 13] An optical system as described in any one of Inventions 1 to 12, wherein the filter is located on the viewing side.

[0048] [Invention 14] A display device comprising the optical system described in any one of Inventions 1 to 13.

[0049] [Effects of the invention]

[0050] The optical system of the present invention can emit polarized light with high contrast. Some aspects can further have high transparency. In addition, some aspects can provide high contrast and high transparency in a display device using the optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A graph showing the transmittance (Ky and Kz) of polarized light emitting elements A to C at each wavelength.

[0052] Figure 2 A graph showing the luminous intensity ratio of polarized light emitting plates A to C at each wavelength.

[0053] Figure 3 A graph showing the polarization degree of polarizing plates A to C at each wavelength.

[0054] Figure 4 A graph showing the transmittance (Ky and Kz) of polarizers A to E at each wavelength.

[0055] Figure 5 A graph showing the transmittance of filters F to H at each wavelength.

[0056] Figure 6 A graph showing the transmittance (Ky and Kz) of the ultraviolet polarizing plate J at each wavelength. DETAILED DESCRIPTION

[0057] The optical system of the present invention comprises a polarized light emitting element and a filter that absorbs light in the visible light region (sometimes referred to as a "visible light absorption filter" or simply a "filter"), wherein the polarized light emitting element absorbs light of a wavelength that is different from at least a portion of the wavelength of the emitted light, has axes with different amounts of light absorption, and can emit polarized light in the visible light region by absorbing light; the filter is a single photometrically corrected filter with a transmittance of 45 to 100%, and can absorb light in the visible light region; the optical system satisfies the relationship of equation (1) or equation (2).

[0058] A em-L-λmax ×F em-L<0.6×A fi-em-λmax <0.35 Formula (1)

[0059] In the formula, A em-L-λmax Indicates the absorbance at the wavelength of the maximum absorption on the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A fi-em-λmax Indicates the absorbance of the above-mentioned filter at the wavelength where the polarized light emitting element exhibits a maximum emission wavelength.

[0060] 0 <TAF em-L <0.7×TA fi-em Formula (2)

[0061] Where, TA fi-em TAF represents the value after the absorption of each wavelength of the above filter in the wavelength range of light emitted by the polarized light emitting element is integrated. em-L It represents the value obtained by integrating the absorbance at each wavelength on the axis where the light absorption of the polarized light emitting element is the lowest and the quantum yield on the axis where the light absorption of the polarized light emitting element is the lowest in the light absorption wavelength range of the polarized light emitting element.

[0062] Here, the phrase “the wavelength of the absorbed light is different from at least a part of the wavelength of the emitted light” means that the wavelength region of the light absorbed by the polarized light emitting element is completely or partially different from the wavelength region of the polarized emitted light. The so-called polarized light that can emit light in the visible light region by absorbing light means an element that can perform polarized light emission by absorbing light, and emits polarized light in the wavelength range of at least 400 to 700 nm. In addition, an element that absorbs light of a specific wavelength and emits light of a wavelength different from the wavelength of the absorbed light is also called a wavelength conversion element, but in the claims and specification of the present application, it is called a “polarized light emitting element” in terms of the point at which the absorbed light is converted into polarized light emission.

[0063] The polarized light emitting element used in the present invention includes a compound having a light absorbing effect in the element (e.g., a polarized light emitting pigment described later), and if the light wavelength conversion function of the compound can be utilized to emit polarized light, or a compound having a function of emitting polarized light can be formed as a layer, that is, there is no particular limitation. If it is limited in a manner that has a light absorbing effect at a specific wavelength, it can be optically designed to allow light other than the wavelength to penetrate, and is not limited to the full wavelength region of visible light, and a light emitting element with a high transmittance of only a specific wavelength can be provided. It is particularly preferred that the element that absorbs light and emits polarized light has an absorption wavelength of light in the ultraviolet region to the near ultraviolet visible light region. By having an absorption wavelength of light in the ultraviolet region to the near ultraviolet visible light region, the light emitting element can be made to emit light using light that is invisible to the eyes or a light source that is difficult to see, and a visual perception can be provided that is a high transmittance element that emits polarized visible light. As for the more preferred type of polarized light-emitting element that emits polarized light, one of the more preferred types of the present application can be listed as: the light absorption region is at least in the ultraviolet region to the near-ultraviolet visible light region, for example, at 300 to 430nm, and the emission wavelength of the polarized light has a wavelength range of at least 400 to 700nm in the visible light region.

[0064] The polarized light emitting element used in the present invention absorbs light in the range of the ultraviolet region to the near ultraviolet visible light region, and emits polarized light with a luminous spectrum peak in at least a part or all of the visible light region set to the range of 400 to 700nm. In the present application, it is more preferred to be light in the ultraviolet region to the near ultraviolet visible light region that is invisible to human eyes or difficult to see clearly, that is, light from 300 to 430nm. In addition, from the perspective of improving visibility, the absorption wavelength of the light of the polarized light emitting element is more preferably 340 to 420nm, more preferably 350 to 410nm, and particularly preferably 350 to 400nm. The light irradiated on the ultraviolet region to the near ultraviolet visible light region of the polarized light emitting element may or may not be polarized, but may have polarization. One of the methods for obtaining the above-mentioned polarized light emitting element can be obtained by at least comprising a substrate and a polarized light emitting pigment described later.

[0065] The polarized light emitted by the polarized light emitting element used in the present invention can be listed as linearly polarized light, circularly polarized light, elliptically polarized light, etc., but from the perspective of display device design, linearly polarized light is more preferred. The so-called linear polarization can also be expressed as a wave in the direction of a certain axis. By passing the linearly polarized light through the polarized light emitting element, that is, by emitting light polarized in one axis, it becomes easy to design a display device such as a liquid crystal display. This is also suitable for use in the industry as most of the liquid crystal displays and polarized lenses sold on the market use iodine-based polarizing plates or dye-based polarizing plates corresponding to linear polarization.

[0066] In order to emit linearly polarized light, for example, it can be achieved by orienting the polarized light-emitting pigment described later in the same direction in the substrate. In addition, by orienting the polarized light-emitting pigment in the same axis again, polarized light with the same axis can be emitted, and the intensity of the light transmitted can be increased, and the pigment can provide light with a stronger luminous intensity than the original theoretical luminous intensity. That is, when the polarized light-emitting pigment is already oriented in the same direction in the substrate, linearly polarized light with higher brightness can be provided. In addition, the linear polarizer can be transformed into various polarizations by combining a phase difference plate, which can facilitate optical design. For example, circularly polarized light can also be emitted by setting a 1 / 4λ plate for the emission wavelength, or the emitted linearly polarized light can be rotated 90° by setting a 1 / 2λ plate for the emission wavelength. As described above, the polarization can be adjusted in various ways by a phase difference plate, so setting a phase difference plate for the polarized light-emitting element can be regarded as a more preferred form of the present application.

[0067] The polarized light emitting element that can be used in the present invention can be exemplified as follows: it contains a polarized light emitting pigment, linearly polarized light is emitted by orienting the polarized light emitting pigment, and axial absorption anisotropy can be manifested at the wavelength of the absorbed light. The so-called axial absorption anisotropy means an axis with strong absorption and an axis with weak absorption. For example, when the polarized light emitting element absorbs light from the ultraviolet region to the near-ultraviolet visible light region, and uses the absorbed light to emit polarized light in the visible light region, the orientation direction of the polarized light emitting pigment in the absorbed light and the absorption amount of light in a direction different from the orientation direction are different. In general, when having this axial absorption anisotropy, it is also referred to as having dichroism. The size of the axial absorption anisotropy (dichroism) obtained by orienting the polarized light emitting pigment is displayed as a dichroic ratio (hereinafter, also recorded as "RD"). The so-called dichroic ratio refers to the ratio of the absorption of the axis with the highest absorption to the absorption of the axis with the lowest absorption. Usually, if it is more than 3, it shows a dichroic ratio (axial absorption anisotropy), preferably higher, more preferably more than 5, more preferably more than 10, particularly preferably more than 20, and more preferably more than 30. If it is about 50, it means that light with a high degree of polarization (or polarization rate) is emitted. If it is about 70, it means that the dichroic ratio (anisotropy) is more apparent, and it also means that the manifestation of the dichroic ratio can emit polarized light with a higher degree of polarization. In addition, the orientation degree of the pigment can also be calculated from the value of the dichroic ratio [hereinafter, recorded as an ordered parameter (Order Parameter)]. The orientation degree of the pigment is a numerical value calculated according to the following formula (5), preferably more than 0.80 and less than 1.00, and particularly preferably more than 0.9 and less than 1.00.

[0068] Order Parameter=(RD-1) / (RD+2) Formula (5)

[0069] (Method for manufacturing polarized light emitting element)

[0070] The method for preparing the polarized light-emitting element that can be used in the present invention can be prepared, for example, by the following steps: a step of preparing a substrate; a swelling step of immersing the substrate in a swelling solution to swell the substrate; a dyeing step of immersing the swollen substrate in a dyeing solution containing at least one of the above-mentioned polarized light-emitting pigments, so that the substrate adsorbs the polarized light-emitting pigment; a cross-linking step of immersing the substrate adsorbed with the polarized light-emitting pigment in a solution containing boric acid, thereby cross-linking the polarized light-emitting pigment in the substrate; an extension step of uniaxially extending the substrate with the cross-linked polarized light-emitting pigment in a certain direction to align the polarized light-emitting pigment in a certain direction; further, depending on the required washing step and / or drying step, the aforementioned washing step washes the extended substrate with a washing solution; and the aforementioned drying step dries the washed substrate.

[0071] <Base material>

[0072] The substrate can use a polymer film for the polarized light emitting pigment described later for adsorption and orientation. The polymer film is preferably a hydrophilic polymer film obtained by film-forming a hydrophilic polymer capable of adsorbing a polarized light emitting pigment with general dichroism, and is particularly preferably a hydrophilic polymer film obtained by film-forming a hydrophilic polymer capable of adsorbing a pigment with a diphenylene skeleton or a pigment with a biphenyl skeleton. The hydrophilic polymer is not particularly limited, but for example, polyvinyl alcohol resin and starch resin are more preferred, and from the viewpoint of dyeability, processability and crosslinking of the polarized light emitting pigment with the above-mentioned dichroism, polyvinyl alcohol resin and its derivatives are more preferred. The above-mentioned polyvinyl alcohol resin and its derivatives can be listed, for example: polyvinyl alcohol or its derivatives, and any of these modified by olefins such as ethylene and propylene, or unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid and maleic acid, etc. Among them, from the point of view of the adsorption and orientation of the polarized light emitting pigment with dichroism, it is suitable to use a film formed by polyvinyl alcohol resin and its derivatives. The substrate can be, for example, a film made of commercially available polyvinyl alcohol resin or its derivatives, or can be made by film-forming polyvinyl alcohol resin. The film-forming method of polyvinyl alcohol resin is not particularly limited, and can be, for example, a method of melt-extruding aqueous polyvinyl alcohol, a film-forming method of spreading, a wet film-forming method, a gel film-forming method (temporarily cooling the polyvinyl alcohol aqueous solution to gel, and then extracting and removing the solvent), a casting film-forming method (spreading the polyvinyl alcohol aqueous solution on a base plate and drying), and a method of combining these, etc., publicly known film-forming methods. The thickness of the substrate is usually 10 to 100 μm, and preferably about 20 to 80 μm.

[0073] The method for producing a polarized light emitting element is described below by taking the case of using a film made of a polyvinyl alcohol-based resin and a derivative thereof as an example.

[0074] (Swelling step)

[0075] The swelling step is preferably performed by immersing the substrate in a swelling liquid at 20 to 50° C. for 30 seconds to 10 minutes, and water is more preferably used as the swelling liquid. The stretching ratio of the substrate is preferably adjusted to 1.00 to 1.50 times, and more preferably adjusted to 1.10 to 1.35 times.

[0076] (Dyeing Steps)

[0077] The dyeing step is to adsorb one or more polarized light emitting dyes described later to the substrate obtained through the above-mentioned swelling step. The dyeing step is not particularly limited as long as it is a method that allows the polarized light emitting dye to be adsorbed on the substrate, and examples thereof include: a method of immersing the substrate in a dyeing solution containing a polarized light emitting dye; or a method of coating the substrate with a dyeing solution containing a polarized light emitting dye, etc., but the method of immersing in a dyeing solution containing a polarized light emitting dye is more preferred. The concentration of the polarized light emitting dye in the dyeing solution is not particularly limited as long as it is a concentration that sufficiently adsorbs the polarized light emitting dye in the substrate, but for example, the concentration of the polarized light emitting dye in the dyeing solution is preferably 0.0001 to 1% by mass, and more preferably 0.0001 to 0.5% by mass. The temperature of the dyeing solution in the dyeing step is preferably 5 to 80°C, more preferably 20 to 50°C, and particularly preferably 40 to 50°C. In addition, the time that substrate is immersed in dyeing solution can be suitably adjusted, and it is more preferred to adjust between 30 seconds to 20 minutes, and it is more preferred to adjust between 1 to 10 minutes. The polarized light emitting pigment contained by dyeing solution can be used alone 1 kind, and it is also possible to use more than 2 kinds. The above-mentioned polarized light emitting pigment is different because of the difference of its pigment structure, so by containing more than 2 kinds of the above-mentioned polarized light emitting pigment in substrate, the luminous color produced can be suitably adjusted into various colors. In addition, as required, the above-mentioned dyeing solution can also include more than 1 kind of organic dye and / or fluorescent dye except comprising the above-mentioned polarized light emitting pigment.

[0078] (Polarized light emitting pigment)

[0079] The polarized light emitting pigment can be cited, for example: a compound or its salt that emits light by utilizing the absorbed light and at least has a diphenylethylene skeleton or a biphenyl skeleton in the molecule, and performs fluorescence or phosphorescence, and it is more preferred to perform fluorescence. Through the polarized light emitting pigment, it has a fluorescence function, and the pigment has a dichroic ratio at the absorption wavelength of light, and polarized light can be emitted. In particular, the polarized light emitting pigment with a diphenylethylene skeleton or a biphenyl skeleton in the pigment molecule has excellent fluorescence characteristics and has a high dichroic ratio at the absorption wavelength by orienting it. These are derived from the characteristics of the above-mentioned skeletons, and these characteristics can be further improved. For the purpose of adjusting various characteristics such as absorption wavelength and emission wavelength, light resistance, moisture resistance, ozone gas resistance, etc., various fastness and solubility, etc., any substituent can be further introduced into the above-mentioned skeletons. When the type of substituent or the selection of the substitution position is less preferred in the introduction of substituents, even if a high degree of polarization is achieved, there are also problems such as a significant decrease in the amount of luminescent light, so in order to make the fluorescent light emission characteristics excellent and have a high dichroic ratio, the type of substituent or the selection of the substitution position becomes particularly important. In addition, the above-mentioned polarized light emitting pigment can be used alone or in combination of two or more.

[0080] (a) Polarized light-emitting pigment with a stilbene skeleton

[0081] The dye having a stilbene skeleton is more preferably a compound represented by the following formula (S) or a salt thereof.

[0082]

[0083] In formula (S), L and M each independently represent a nitro group, an amine group which may have a substituent, a carbonylamide group which may have a substituent, a naphthtriazole group which may have a substituent, an alkyl group having 1 to 20 carbon atoms which may have a substituent, a vinyl group which may have a substituent, an amide group which may have a substituent, a urea group which may have a substituent, an aryl group which may have a substituent, or a carbonyl group which may have a substituent.

[0084] It is known that the dye having a stilbene skeleton represented by the above formula (S) emits fluorescent light and can obtain dichroism by orientation. However, this is mainly derived from the stilbene skeleton, and any substituent may be further introduced.

[0085] Examples of the amino group which may have a substituent include: an unsubstituted amino group, a methylamino group, an ethylamino group, an n-butylamino group, a tert-butylamino group, an n-hexylamino group, a dodecylamino group, a dimethylamino group, a diethylamino group, a di-n-butylamino group, an ethylmethylamino group, an ethylhexylamino group, etc., which may have a substituent; an arylamino group which may have a substituent, such as a phenylamino group, a diphenylamino group, a naphthylamino group, an N-phenyl-N-naphthylamino group; an alkylamino group which may have a substituent, such as a methylcarbonylamino group, an ethylcarbonylamino group, an n-butyl-carbonylamino group, etc., which may have a substituent; carbonylamino; arylcarbonylamino which may have a substituent such as phenylcarbonylamino, biphenylcarbonylamino, naphthylcarbonylamino, etc.; alkylsulfonylamino having 1 to 20 carbon atoms such as methylsulfonylamino, ethylsulfonylamino, propylsulfonylamino, n-butylsulfonylamino, etc.; arylsulfonylamino which may have a substituent such as phenylsulfonylamino, naphthylsulfonylamino, etc., and more preferably alkylcarbonylamino having 1 to 20 carbon atoms which may have a substituent, arylcarbonylamino which may have a substituent, alkylsulfonylamino having 1 to 20 carbon atoms, arylsulfonylamino which may have a substituent. In addition, the substituents in the above-mentioned alkylamino group having 1 to 20 carbon atoms which may have a substituent, the arylamino group which may have a substituent, the alkylcarbonylamino group having 1 to 20 carbon atoms which may have a substituent, the arylcarbonylamino group which may have a substituent, the alkylsulfonylamino group having 1 to 20 carbon atoms, and the arylsulfonylamino group which may have a substituent are not particularly limited, but examples thereof include a nitro group, a cyano group, a hydroxyl group, a sulfonic acid group, a phosphoric acid group, a carboxyl group, a carboxyalkyl group, a halogen atom, an alkoxy group, an aryloxy group, and the like.

[0086] Examples of the carboxyalkyl group include methylcarboxyl and ethylcarboxyl. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine. Examples of the alkoxy group include methoxy, ethoxy, and propoxy. Examples of the aryloxy group include phenoxy and naphthoxy.

[0087] Examples of the carbonylamide group which may have a substituent include an N-methyl-carbonylamide group (-CONHCH3), an N-ethyl-carbonylamide group (-CONHC2H5), and an N-phenyl-carbonylamide group (-CONHC6H5).

[0088] Examples of the naphthotriazolyl group which may have a substituent include a benzotriazolyl group and a naphthotriazolyl group.

[0089] Examples of the alkyl group having 1 to 20 carbon atoms which may have a substituent include straight-chain alkyl groups such as methyl, ethyl, n-butyl, n-hexyl, n-octyl, and n-dodecyl; branched-chain alkyl groups such as isopropyl, sec-butyl, and tert-butyl; and cyclic alkyl groups such as cyclohexyl and cyclopentyl.

[0090] Examples of the vinyl group which may have a substituent include vinyl group, methylvinyl group, ethylvinyl group, divinyl group, and pentadienyl group.

[0091] Examples of the amide group which may have a substituent include an acetamide group (-NHCOCH3) and a benzamide group (-NHCOC6H5).

[0092] Examples of the aryl group which may have a substituent include a phenyl group, a naphthyl group, an anthracenyl group, and a biphenyl group.

[0093] Examples of the carbonyl group which may have a substituent include a methylcarbonyl group, an ethylcarbonyl group, an n-butyl-carbonyl group, and a phenylcarbonyl group.

[0094] There are no particular restrictions on the substituents in the above-mentioned carbonylamide group which may have a substituent, naphthotriazole group which may have a substituent, alkyl group having 1 to 20 carbon atoms which may have a substituent, vinyl group which may have a substituent, amide group which may have a substituent, urea group which may have a substituent, aryl group which may have a substituent, and carbonyl group which may have a substituent, but they may be the same as the substituents described in the paragraph of the above-mentioned amine group which may have a substituent.

[0095] The pigment with stilbene skeleton shown in the above-mentioned formula (S) is particularly preferred with the pigment shown in the following formula (Sa) or its salt or the pigment shown in the following formula (Sb) or its salt. By using these pigments, the light of various colors can be emitted by combining a plurality of these pigments, for example, the polarized light emitting element emitting white light can be obtained.

[0096]

[0097] In formula (Sa), R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an amino group which may have a substituent, and n represents an integer of 0 to 3.

[0098] In formula (Sb), Y represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, a vinyl group which may have a substituent, or an aryl group which may have a substituent.

[0099] In the above formula (Sa), the halogen atom may be the same as described above. The alkyl group which may have a substituent may be the same as described in the paragraph of the alkyl group having 1 to 20 carbon atoms which may have a substituent. The alkoxy group which may have a substituent is preferably a methoxy group or an ethoxy group. The amino group which may have a substituent may be the same as described above, and is preferably a methylamino group, a dimethylamino group, an ethylamino group, a diethylamino group, or a phenylamino group. The substituent R may be bonded to any carbon of the naphthalene ring in the naphthotriazole ring, but when the carbon condensed with the triazole ring is at the 1st and 2nd positions, it is more preferred to bond to the 3rd, 5th or 8th positions. n is an integer from 0 to 3, and is preferably 1 or 2. The -(SO3H) group may be bonded to any carbon of the naphthalene ring in the naphthotriazole ring. As for the substitution position in the naphthalene ring of the -(SO3H) group, when n=1, and the carbon condensed with the triazole ring is at the 1st and 2nd positions, the 4th, 6th, or 7th positions are more preferred; when n=2, the 5th and 7th positions, and the 6th and 8th positions are more preferred; when n=3, the combination of the 3rd, 6th, and 8th positions is more preferred. In addition, it is particularly preferred that R is a hydrogen atom and n is 1. X represents a nitro group or an amine group which may have a substituent, and a nitro group is more preferred. The amine group which may have a substituent may be the same as described above, and more preferably, an alkylcarbonylamino group having 1 to 20 carbon atoms which may have a substituent, an arylcarbonylamino group which may have a substituent, an alkylsulfonylamino group having 1 to 20 carbon atoms, or an arylsulfonylamino group which may have a substituent.

[0100] In the above formula (Sb), Y is preferably an aryl group which may have a substituent, more preferably a naphthyl group which may have a substituent, and particularly preferably a naphthyl group substituted with an amino group or a sulfo group as a substituent. Z represents the same substituent as described for X in the above formula (Sa), and more preferably a nitro group.

[0101] Examples of the compound represented by the formula (S) include Kayaphor series (manufactured by Nippon Kayaku Co., Ltd.), Whitex series such as Whitex RP (manufactured by Sumitomo Chemical Co., Ltd.), etc. In addition, the compound represented by the formula (S) is exemplified below, but is not limited to these.

[0102]

[0103]

[0104] (b) Polarized light-emitting pigments with a biphenyl skeleton

[0105] The dye having a biphenyl skeleton is more preferably a compound represented by the following formula (B) or a salt thereof.

[0106]

[0107] In formula (B), P and Q each independently represent a nitro group, an amine group which may have a substituent, a carbonylamide group which may have a substituent, a naphthotriazole group which may have a substituent, an alkyl group having 1 to 20 carbon atoms which may have a substituent, a vinyl group which may have a substituent, an amide group which may have a substituent, a urea group which may have a substituent, or an aryl group which may have a substituent, or a carbonyl group which may have a substituent.

[0108] In the above formula (B), P and Q each independently represent a nitro group, an amine group which may have a substituent, a carbonylamide group which may have a substituent, a naphthotriazole group which may have a substituent, an alkyl group having 1 to 20 carbon atoms which may have a substituent, a vinyl group which may have a substituent, an amide group which may have a substituent, a urea group which may have a substituent, or an aryl group which may have a substituent, or a carbonyl group which may have a substituent, but are not necessarily limited to these. The amine group which may have a substituent, the carbonylamide group which may have a substituent, the naphthotriazole group which may have a substituent, an alkyl group having 1 to 20 carbon atoms which may have a substituent, a vinyl group which may have a substituent, an amide group which may have a substituent, an aryl group which may have a substituent, and a carbonyl group which may have a substituent may be the same as those described above.

[0109] The compound represented by the above formula (B) is more preferably a compound represented by the following formula (Ba).

[0110]

[0111] In formula (Ba), R1, R2, R3 and R4 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aralkyloxy group, an alkenyloxy group, an alkylsulfonyl group having 1 to 4 carbon atoms, an arylsulfonyl group having 6 to 20 carbon atoms, a formamide group, a sulfonamide group, or a carboxyalkyl group, and j or k each independently represents an integer from 0 to 2.

[0112] The preferred substitution position of the -(SO3H) group in the above formula (Ba) is not particularly limited, but when the vinyl group is at the 1-position, the 2-position and 4-position are more preferred, and the 2-position is particularly preferred.

[0113] In the above formula (Ba), the carboxyalkyl group may be the same as described above.

[0114] Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl, n-butyl, sec-butyl, tert-butyl, and cyclobutyl. Examples of the alkoxy group having 1 to 4 carbon atoms include methoxy, ethoxy, propoxy, n-butoxy, sec-butoxy, tert-butoxy, and cyclobutyl. Examples of the aralkyloxy group include aralkyloxy groups having 7 to 18 carbon atoms. Examples of the alkenyloxy group include alkenyloxy groups having 1 to 18 carbon atoms. Examples of the alkylsulfonyl group having 1 to 4 carbon atoms include methylsulfonyl, ethylsulfonyl, propylsulfonyl, n-butylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, and cyclobutylsulfonyl. Examples of the arylsulfonyl group having 6 to 20 carbon atoms include phenylsulfonyl, naphthylsulfonyl, and biphenylsulfonyl.

[0115] In the above formula (Ba), the preferred substitution positions of R 1 to R 4 are preferably the 1-position of the vinyl group, and the 2-position and 4-position are more preferred.

[0116] The polarized light emitting dye represented by the above formula (Ba) can be prepared by a publicly known method, and can be obtained, for example, by condensing 4-nitrobenzaldehyde-2-sulfonic acid with a phosphonate and then reducing the nitro group.

[0117] As the compound represented by the above formula (B), the compounds described in Patent Document 6 and the like can be used, and specifically, the following compounds and the like are exemplified.

[0118]

[0119] (c) Luminescent pigments with coumarin skeleton

[0120] The compound having a coumarin skeleton serving as a luminescent pigment is preferably a compound represented by the following formula (C) or a salt thereof.

[0121]

[0122] In formula (C), A represents a coumarin compound which may have a substituent, X represents a sulfo group or a carboxyl group, and p represents an integer from 1 to 3. The coumarin compound represented by formula (C) represents a water-soluble luminescent pigment having a coumarin skeleton.

[0123] When the above formula (C) is the following formula (Ca), the contrast of polarized light emission is further improved, so it is a more preferred example. In formula (Ca), the groups R5 and R6 each independently represent a hydrocarbon group having 1 to 10 carbon atoms, Q represents a sulfur atom, an oxygen atom, or a nitrogen atom, and q represents an integer from 1 to 3.

[0124]

[0125] As described above, the luminescent pigment of the water-soluble coumarin compound represented by formula (C) or formula (Ca) in the present invention has at least one coumarin skeleton in the molecule. The luminescent pigment of the water-soluble coumarin compound of the present invention exhibits polarized luminescence by irradiation with ultraviolet light and visible light (specifically, light of 300 to 600 nm) because it has a coumarin skeleton.

[0126] The salts of the compounds represented by the above formulae (S), (B) and (C) are salts formed with inorganic cations or organic cations. The inorganic cations are alkali metals, for example, lithium, sodium, potassium and ammonium ions (NH4 + ). Examples of the organic cation include organic ammonium represented by the following formula (A).

[0127]

[0128] In formula (A), Z1 to Z4 each independently represent a hydrogen atom, an alkyl group, a hydroxyalkyl group, or a hydroxyalkoxyalkyl group, and at least one of Z1 to Z4 is a group other than a hydrogen atom.

[0129] Specific examples of Z1 to Z4 include C1-C6 alkyl groups such as methyl, ethyl, butyl, pentyl and hexyl, and C1-C4 alkyl groups are more preferred; hydroxy C1-C6 alkyl groups such as hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl and 2-hydroxybutyl, and hydroxy C1-C4 alkyl groups are more preferred; and hydroxy C1-C6 alkoxy C1-C6 alkyl groups such as hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 3-hydroxyethoxybutyl and 2-hydroxyethoxybutyl, and hydroxy C1-C4 alkoxy C1-C4 alkyl groups are more preferred.

[0130] Among these inorganic cations and organic cations, more preferred examples include sodium ions, potassium ions, lithium ions, monoethanolammonium ions, diethanolammonium ions, triethanolammonium ions, monoisopropanolammonium ions, diisopropanolammonium ions, triisopropanolammonium ions, and ammonium ions. Among these, lithium ions, ammonium ions, and sodium ions are more preferred.

[0131] As for other polarized light emitting pigments that can be used in the above-mentioned polarized light emitting element, for example, CIFluorescent Brighter 5, CIFluorescent Brighter 8, CIFluorescent Brighter 12, CIFluorescent Brighter 28, CIFluorescent Brighter 30, CIFluorescent Brighter 33, CIFluorescent Brighter 350, CIFluorescent Brighter 360, CIFluorescent Brighter 365, etc. These fluorescent dyes can be free acids, or alkali metal salts (such as Na salts, K salts, Li salts), ammonium salts or amine salts.

[0132] The polarized light emitting pigments can be oriented singly or in combination of two or more. When two or more polarized light emitting pigments are used in combination, various luminous colors can be adjusted by adjusting the mixing ratio of these polarized light emitting pigments. ＊ Value and b ＊ The absolute values ​​of the values ​​are all adjusted to be less than 5, so that the polarized light emitted by the polarized light emitting element becomes white. ＊ Value and b ＊ The value is obtained based on the spectral distribution of light emitted from the polarized light emitting element when light is incident on each polarized light emitting element, in accordance with JIS Z 8781-4:2013. The method of expressing the color of an object determined in accordance with JIS Z 8781-4:2013 is equivalent to the method of expressing the color of an object established by the International Commission on Illumination (abbreviated as "CIE"). Chromaticity a ＊ Value and b ＊ The chromaticity a is usually determined by irradiating the sample with natural light. However, in the specification and claims of the present application, the chromaticity a can be determined by irradiating the polarized light emitting element with short-wavelength light such as ultraviolet light and measuring the emitted light. ＊ Value and b ＊ Value. The luminous light of a ＊ The absolute value of is 5 or less, more preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less. ＊ The absolute value of is 5 or less, more preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less. ＊ Value and b ＊If the absolute values ​​of the values ​​are independently less than 5, it can be perceived as white by the human eye. In addition, if they are all less than 5, it can be perceived as a more preferred white luminescence. Since the polarized light emitted is white, it can be used as a natural light source such as sunlight, a light source of a paper white terminal, etc., and it has the advantage of being easy to use even when placed in a display using a color filter, etc. For the luminous intensity, if the light can be perceived by the eyes, it will be no problem to apply it to a display. In particular, for the present application, it is important that the emitted light has a high degree of polarization and a high transmittance in the visible light region.

[0133] (D) Other pigments

[0134] The polarized light emitting element preferably contains a single or multiple pigments or their salts having a stilbene skeleton, a biphenyl skeleton or a coumarin skeleton, but may contain one or more other organic dyes or other fluorescent dyes as needed for the purpose of adjusting the color, etc., within the range that does not hinder the polarized light emitting function. Other organic dyes are not particularly limited as long as they can control the color (hue) or luminous color of the polarized light emitting element, but are preferably high in dichroism, and are preferably pigments that have little effect on the polarization of the stilbene skeleton or the biphenyl skeleton in the ultraviolet light region. Such other organic dyes include, for example, CI Direct Yellow 12, CI Direct Yellow 28, CI Direct Yellow 44, CI Direct Orange 26, CI Direct Orange 39, CI Direct Orange 71, CI Direct Orange 107, CI Direct Red 2, CI Direct Red 31, CI Direct Red 79, CI Direct Red 81, CI Direct Red 247, CI Direct Blue 69, CI Direct Blue 78, CI Direct Green 80, and CI Direct Green 59. These organic dyes may be free acids, or may be alkali metal salts (e.g., Na salts, K salts, Li salts), ammonium salts, or amine salts. In addition, as for the above-mentioned other fluorescent dyes, generally speaking, the disclosed fluorescent dyes may also be used for the purpose of adjusting the luminescent color, and there is no particular limitation.

[0135] When the above-mentioned other organic dyes or other fluorescent dyes are used in combination, in order to adjust the color of the desired polarized light emitting element, the dyes to be mixed can be selected and the mixing ratio can be adjusted. The mixing ratio of the organic dye or fluorescent dye is not particularly limited according to the purpose of modulation, but the total amount of these other organic dyes or other fluorescent dyes is preferably used in the range of 0.01 to 10 parts by mass relative to 100 parts by mass of the polarized light emitting element.

[0136] In addition to containing the above-mentioned dyes, the dyeing solution may further contain dyeing auxiliaries as needed. Examples of dyeing auxiliaries include sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulfate (glauber's salt), anhydrous sodium sulfate, and sodium tripolyphosphate, and sodium sulfate is more preferred. The content of the dyeing auxiliaries can be arbitrarily adjusted according to the dyeability of the dye used, the above-mentioned immersion time, and the temperature of the dyeing solution, but 0.0001 to 10% by mass is more preferred in the dyeing solution, and 0.0001 to 2% by mass is more preferred.

[0137] After the above-mentioned dyeing step, in order to remove the dyeing solution attached to the surface of the substrate in the dyeing step, a preliminary washing step can be arbitrarily performed. By performing the preliminary washing step, the dye remaining on the surface of the substrate can be inhibited from migrating to the liquid to be treated subsequently. For the preliminary washing step, water is generally used as the washing liquid. The washing method is preferably to immerse the dyed substrate in the washing liquid. On the other hand, the washing can also be performed by applying the washing liquid to the substrate. The washing time is not particularly limited, but it is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds. The temperature of the washing liquid in the preliminary washing step must be a temperature at which the material constituting the substrate will not dissolve, and generally the washing treatment is applied at 5 to 40°C. In addition, even if the preliminary washing step is not performed, it will not have a particularly large impact on the performance of the polarized light-emitting element, so the preliminary washing step can also be omitted.

[0138] (Cross-linking step)

[0139] After the dyeing step or the preliminary washing step, the substrate may contain a crosslinking agent. The method of making the substrate contain a crosslinking agent is preferably to immerse the substrate in a treatment solution containing a crosslinking agent. On the other hand, the treatment solution may be coated or applied to the substrate. The crosslinking agent in the treatment solution is, for example, a solution containing boric acid. The solvent in the treatment solution is not particularly limited, but water is more preferred. The concentration of boric acid in the treatment solution is preferably 0.1 to 15% by mass, and more preferably 0.1 to 10% by mass. The temperature of the treatment solution is preferably 30 to 80°C, and more preferably 40 to 75°C. In addition, the treatment time of the crosslinking step is preferably 30 seconds to 10 minutes, and more preferably 1 to 6 minutes. The method for manufacturing a polarized light-emitting element of the present invention has the crosslinking step, and accordingly, the polarization degree of the light emitted by the obtained polarizing element is high, and a high contrast is displayed as a display body. Such an effect is an excellent effect that is completely unpredictable by the function of boric acid used in the known technology for the purpose of improving water resistance or light transmittance. Moreover, in the cross-linking step, as needed, an aqueous solution of a cationic polymer compound may be further combined for a fixation treatment. Through this fixation treatment, the dye in the polarized light-emitting element can be fixed. At this time, as for the cationic polymer compound, for example, a cation can be used; a polycondensate of dicyanamide and formalin can be used for the dicyano system; a dicyandiamide / diethylenetriamine polycondensate can be used for the polyamine system; an epichlorohydrin / dimethylamine addition polymer, a dimethyldiallylammonium chloride / dioxide ion copolymer, a diallylamine salt polymer, a dimethyldiallylammonium chloride polymer, an allylamine salt polymer, a dialkylaminoethyl acrylate quaternary salt polymer, etc. can be used for the polycationic system.

[0140] (Extended Steps)

[0141] After the cross-linking step, a stretching step is performed. The stretching step is performed by uniaxially stretching the substrate in a certain direction, which can be either a wet stretching method or a dry stretching method. The stretching ratio is preferably 3 times or more, and more preferably 5 to 8 times.

[0142] In the above-mentioned wet stretching method, it is more preferred to stretch the substrate in water, a water-soluble organic solvent or a mixed solution thereof. It is more preferred to immerse the substrate in a solution containing at least one cross-linking agent and simultaneously perform the stretching treatment. The cross-linking agent may be, for example, the boric acid in the above-mentioned cross-linking agent step, and it is more preferred that the stretching treatment be performed in the treatment solution used in the cross-linking step. The stretching temperature is preferably 40 to 70°C, and more preferably 45 to 60°C. The stretching time is generally 30 seconds to 20 minutes, and more preferably 2 to 7 minutes. The wet stretching step can be implemented by one-stage stretching, or by multiple-stage stretching of more than two stages. In addition, the stretching treatment can be arbitrarily performed before the dyeing step, and in this case, the dye can also be oriented at the time of dyeing.

[0143] In the above-mentioned dry stretching method, when the stretching heating medium is an air medium, it is more preferred to stretch the substrate at a temperature of the air medium of room temperature to 180°C. In addition, the humidity is preferably in an environment of 20 to 95% RH. The heating method of the substrate can be, for example, a roller zone stretching method, a roller heating stretching method, a hot press stretching method, and an infrared heating stretching method, but is not limited to these stretching methods. The dry stretching step can be implemented by a single-stage stretching or a multi-stage stretching method of more than two stages.

[0144] (Washing Steps)

[0145] During the above-mentioned stretching step, since there may be precipitation of the crosslinking agent or foreign matter attached to the surface of the substrate, a washing step of washing the surface of the substrate may be performed. The washing time is preferably 1 second to 5 minutes. The washing method is preferably to immerse the substrate in a washing liquid. On the other hand, the washing can also be performed by coating or applying the washing liquid to the substrate. Water is preferably used as the washing liquid. The washing treatment can be carried out in one stage or in multiple stages of more than two stages. The temperature of the washing liquid in the washing step is not particularly limited, but is usually 5 to 50°C, preferably 10 to 40°C, and may also be room temperature.

[0146] As for the solvent of the solution or treatment liquid used in each of the above steps, in addition to the above-mentioned water, for example, alcohols such as dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropanol, glycerol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or trimethylolpropane; amines such as ethylenediamine and diethylenetriamine, etc. can also be listed. The solvent of the solution or treatment liquid is not limited to these, but water is most preferably used. In addition, the solvents of these solutions or treatment liquids can be used alone or as a mixture of two or more.

[0147] (Drying Step)

[0148] After the above-mentioned washing step, a drying step of the substrate is performed. Although the drying treatment can be performed by natural drying, in order to further improve the drying efficiency, it can be performed by roller compression and removing surface moisture by air knife or water suction roller, etc., and air drying can also be performed. The temperature of the drying treatment is preferably 20 to 100°C, and more preferably 60 to 100°C. The drying time is preferably 30 seconds to 20 minutes, and more preferably 5 to 10 minutes.

[0149] The above method is an example of a method for producing a polarized light emitting element that can be used in the present invention. Since the above dyes do not decompose even in a high temperature or high humidity environment, a polarized light emitting element with high durability can be obtained.

[0150] For a polarized light emitting element including a polarized light emitting dye used in the present application, for example, a compound or salt thereof having at least one of the above-mentioned stilbene skeleton, biphenyl skeleton or coumarin skeleton in the structure, which is a more preferred polarized light emitting dye used in the present application, and emitting fluorescence, it is irradiated with light in the ultraviolet region to the near ultraviolet visible light region, that is, irradiated with light in the non-visible light region, and absorbs light in the ultraviolet region to the near ultraviolet visible light region, and can use the energy of the light to emit polarized light in the visible light region. The light emitted by the polarized light emitting element is polarized light in the visible light region, so when the polarized light emitting element is observed through a general polarizing plate for light in the visible light region, by changing the angle of the axis of the polarizing plate in the visible light region, the strong light emission axis light and the weak light emission axis light (or non-light emission axis light) of the polarized light can be respectively recognized. The polarization degree of the polarized light emitted by the polarized light emitting element is 70% or more and 100% or less, preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, and particularly preferably 98% or more.

[0151] As for the polarized light emitting pigment used in the present application, for example, the polarized light emitting pigment used in the present application which is more preferred, has at least any one of the above-mentioned diphenylethylene skeleton, biphenyl skeleton or coumarin skeleton in the structure, and the polarized light emitting element containing the compound or its salt which emits fluorescence can not absorb the light in the visible light region and allow it to pass through. That is, the transmittance in the visible light region of the polarized light emitting element can provide a high transmittance after the transmittance corrected by the photometric, and can provide a transmittance which is 30 to 35% higher than the parallel transmittance in the case where the liquid crystal display uses a general polarizing plate. In the polarized light emitting element used in the present application, if the monomer transmittance corrected by the photometric is 50% or more, a liquid crystal display which is significantly and dramatically higher in transmittance than the well-known liquid crystal display can be obtained, and it is more preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and particularly preferably 90% or more. The above-mentioned polarized light-emitting element having at least any one of a diphenylethylene skeleton, a biphenyl skeleton or a coumarin skeleton in its structure and containing a fluorescent compound or its salt has a smaller absorption in the visible light region in the non-luminescent state, and a polarized light-emitting element with a high transparency in appearance can be obtained, so it is more preferred. In addition, since it can emit polarized light with high brightness, a high-brightness polarized light-emitting element can be provided.

[0152] [Polarized light panel]

[0153] For the polarized light emitting element, a transparent protective film may be further provided to form a polarized light emitting plate having a transparent protective film. The transparent protective film is used to improve the durability and operability of the polarized light emitting element, and the transparent protective film does not have any effect on the axial absorption anisotropy or polarized light emission displayed by the polarized light emitting element. The transparent protective film may be provided on both sides of the polarized light emitting element, but may also be provided on only one side, that is, may be provided on only one single side.

[0154] The above-mentioned transparent protective film is preferably a transparent protective film with excellent optical transparency and mechanical strength. In addition, the transparent protective film is preferably a film with a layer shape that can maintain the film shape, and is preferably a plastic film that is excellent in thermal stability, moisture shielding, etc. in addition to transparency and mechanical strength. The materials forming such a transparent protective film can be listed, for example: cellulose acetate film, acrylic film, fluorine film such as tetrafluoroethylene / hexafluoropropylene copolymer, or a film composed of polyester resin, polyolefin resin or polyamide resin, etc., and it is more preferred to use triacetyl cellulose (TAC) film or cycloolefin film. The thickness of the transparent protective film is preferably in the range of 1μm to 200μm, more preferably in the range of 10μm to 150μm, and particularly preferably in the range of 40μm to 100μm. The method of setting a transparent protective film on the above-mentioned polarized light-emitting element is not particularly limited, but for example, a transparent protective film can be overlapped on the polarized light-emitting element and laminated in a publicly known manner.

[0155] The polarized light emitting plate may be provided with a bonding agent layer for bonding the transparent protective film and the polarized light emitting element, respectively. The bonding agent constituting the bonding agent layer is not particularly limited, but examples thereof include: polyvinyl alcohol bonding agents, amine emulsion bonding agents, acrylic bonding agents, polyester / isocyanate bonding agents, etc., and polyvinyl alcohol bonding agents are preferably used. After forming the bonding agent layer, the polarized light emitting plate may be manufactured by drying or heat treating at an appropriate temperature.

[0156] In addition, the above-mentioned polarized light emitting plate may be appropriately provided with various publicly known functional layers such as an anti-reflection layer, an anti-glare layer, and a further transparent protective layer on its exposed surface. When making such a layer with various functionalities, it is more preferred to apply a material with various functionalities to the exposed surface of the transparent protective layer, and various functional layers or films can also be attached to the exposed surface of the transparent protective layer via a binder or adhesive. Further transparent protective layers can be listed, for example, as protective layers such as hard coatings such as acrylic resins, polysiloxane resins, and amine resins. In addition, in order to further improve the transmittance, an anti-reflection layer can also be provided on the exposed portion of the transparent protective layer. The anti-reflection layer can be formed, for example, by evaporating or sputtering a substance such as silicon dioxide or titanium oxide onto the transparent protective layer, or by thinly coating a fluorine-based substance on the above-mentioned transparent protective layer.

[0157] (Optical System)

[0158] The optical system of the present invention can be obtained by setting a light absorption filter with a light intensity correction monomer transmittance of 45 to 100% on the polarized light emitting element or polarized light emitting plate obtained above in a manner that satisfies the following formula (1) or formula (2).

[0159] A em-L-λmax ×F em-L <0.6×A fi-em-λmax <0.35 Formula (1)

[0160] In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A fi-em-λmax Indicates the absorbance of the aforementioned filter at the maximum emission wavelength of the polarized light emitting element.

[0161] 0 <TAF em-L <0.7×TA fi-em Formula (2)

[0162] Where, TA fi-em TAF represents the value obtained by integrating the absorbance of each wavelength of the above-mentioned filter in the wavelength range where the polarized light emitting element emits light. em-L It represents the value obtained by integrating the product of the absorbance at each wavelength of the axis where the light absorption of the polarized light emitting element is the lowest and the quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest in the light absorption wavelength range of the polarized light emitting element.

[0163] Here, the light absorption filter becomes a filter that absorbs light of the wavelength emitted by the polarized light-emitting element. By satisfying the above formula (1), it can effectively reduce the light of the maximum emission wavelength of the polarized light-emitting element on the weak axis, thereby obtaining an optical system with high contrast of polarized light emission.

[0164] More preferably, the light can effectively reduce the wavelength of the maximum emission of the polarized light emitting element on the weak axis by satisfying the following formula (1-a).

[0165] A em-L-λmax ×F em-L <0.9×A fi-em-λmax <0.35 Formula (1-a)

[0166] It is more preferred that the luminous intensity of the strongest wavelength of the polarized light-emitting element on the weak axis (spectral peak intensity of the weak axis) can be substantially eliminated by satisfying the following formula (1-b), and an optical system with high brightness can be obtained, that is, an optical system with high contrast of polarized light emission can be obtained, which is more preferred.

[0167] A em-L-λmax ×F em-L <1.0×A fi-em-λmax <0.35 Formula (1-b)

[0168] Since the light of the polarized light emitting element with the maximum emission wavelength on the weak axis can be effectively reduced by using a light absorption filter, the absorbance of the filter (hereinafter also represented as "A") which absorbs the light in the visible light region with the maximum emission wavelength of the polarized light emitting element is fi-em-λmax The product of A and 0.6 is preferably 0.35 or less. By making A less than 0.35, an optical system capable of providing high-brightness polarized light emission can be obtained. fi-em-λmax The value of is more preferably below 0.30, more preferably below 0.22, particularly preferably below 0.18, and even more particularly preferably below 0.15. By setting it to below 0.30, an optical system having high transmittance and capable of providing high-contrast polarized light emission can be obtained, so it is more preferred.

[0169] Alternatively, by satisfying the above formula (2), the light emission of the polarized light emitting element on the weak axis can be reduced, thereby obtaining an optical system with a high contrast of polarized light emission.

[0170] More preferably, the emission intensity of the polarized light emitting element on the weak axis can be further reduced by satisfying the following formula (2-a).

[0171] 0 <TAF em-L <0.85×TA fi-em Formula (2-a)

[0172] More preferably, an optical system with a high contrast of polarized light emission can be obtained by substantially eliminating the light emission of the polarized light emitting element on a weak axis by satisfying the following formula (2-b).

[0173] 0 <TAF em-L <1.0×TA fi-em Formula (2-b)

[0174] As described above, the optical system of the present invention can be achieved by satisfying the above formula (1) or the above formula (2). By satisfying formula (1) or formula (2), an optical system having high transmittance and high polarization, that is, a bright light position and an extinction position with high contrast can be obtained. The emission spectrum of the polarized light-emitting element at the weak light-emitting position can be suppressed by formula (1), and the amount of light of the polarized light-emitting element at the weak light-emitting position can be suppressed by formula (2). Therefore, in order to obtain light having high transmittance and high polarization, that is, an optical system having high contrast bright light position and extinction position, formula (1) and formula (2) are respectively suitable conditions. It is more preferred to satisfy at least formula (2), and it is more preferred to satisfy both formula (1) and formula (2).

[0175] (Light filter that absorbs visible light)

[0176] By making the transmittance of the photometric correction monomer of the filter used in the present invention 45 to 100%, an optical system with high transparency can be obtained. When the polarized light emitting element used in the present invention has all or part of the absorption wavelength of light in the ultraviolet region to the near ultraviolet visible light region (specifically, 300 to 430nm), it has high transparency because the absorption of light in the range of 400 to 700nm is significantly lower. Therefore, an optical system with higher transparency can be obtained by making the transmittance of the photometric correction monomer of the aforementioned filter 50 to 99.9%, preferably 60 to 99.9%, more preferably 70 to 99.9%, and even more preferably 80 to 99.9%.

[0177] In addition, when the aforementioned filter is provided, it is more preferred that the transmittance of each wavelength of the polarized light-emitting element, especially the transmittance of each wavelength in the wavelength band region where light is emitted, is 45 to 100%. Based on this, an optical system with high contrast and high transparency can be obtained more effectively, so it is more preferred. By having the transmittance of the aforementioned filter in the emission wavelength of the polarized light-emitting element be 50 to 99.9%, a more preferred form of the present application can be achieved, and it is more preferably 60 to 99.9%, more preferably 70 to 99.9%, and even more preferably 80 to 99.9%. By arranging such a filter on the side where people see, it is more preferred to provide high contrast in the optical system of the present application for people who see.

[0178] The visible light absorption filter used in the present invention is preferably a polarizing element or a polarizing plate. The so-called polarizing plate means that a transparent protective film is provided on the polarizing element (in other words, the polarizing plate has a polarizing element and a transparent protective film). The transparent protective film is preferably used so as not to cause any hindrance to the optical properties of the aforementioned polarizing element, and has no light absorption for light in the ultraviolet region. The aforementioned polarizing element is not particularly limited if it has axial absorption anisotropy for light in the visible light region, that is, it has a polarizing function, because by using a polarizing element whose monomer transmittance or its monomer absorbance satisfies the above formula (1) or the above formula (2), an optical system with high brightness or high contrast equal to or higher than that of the aforementioned filter (the aforementioned polarizing element) can be provided, so it is more preferred.

[0179] The polarizing plate using the polarizing element may be exemplified by an iodine-based polarizing plate, a dye-based polarizing plate, a dye-based polarizing plate capable of controlling polarization of only a specific wavelength, a polarizing plate using a polyene type, a wire grid type polarizing plate, a reflective polarizing plate, etc. The polarizing element has polarization performance for light in a part or all of the wavelength region of 400 to 700 nm. Examples of iodine-based polarizing plates include Japanese Patent Publication No. 2001-290029 and Japanese Patent Publication No. 2010-072548; examples of dye-based polarizing plates include Japanese Patent Publication No. 2001-033627, Japanese Patent Publication No. 2004-251962, and Patent Document 7; examples of dye-based polarizing plates that can only polarize and control a specific wavelength include Japanese Patent Publication No. 2007-084803, Japanese Patent Publication No. 2007-238888, WO2012-165223, and Patent Document 8; examples of polarizing plates using polyenes include Japanese Patent Publication No. 2005-527847 and Japanese Patent Publication No. 2005-517974; examples of wire-grid-type polarizing plates include Japanese Patent Publication No. 2003-519818 and Japanese Patent Publication No. 2003-502708. Examples of the reflective polarizing plate include U.S. Pat. No. 3,610,729, WO95 / 17303, WO95 / 17692, WO95 / 17699, WO96 / 19347, WO99 / 36262, WO2005 / 0888363, Japanese Patent Application Laid-Open No. 2007-298634, and WO2011 / 074701. Examples of the product include 3M Company's DBEF. As for the polarizing element, it is more preferred that the transmittance of the monomer satisfies the above formula (1) or the above formula (2), or satisfies the following formula (3) or the following formula (4) described later, and has high long-term storage stability and stable durability even under harsh conditions, so it is more preferred to use a dye-based polarizing plate and a polarizing plate using a polyene type, and in terms of having high durability even under high temperature and high temperature and high humidity environments, a dye-based polarizing plate obtained by containing a dichroic dye in a substrate such as a polyvinyl alcohol film and extending it in a boric acid aqueous solution is particularly preferred. In addition, the so-called dichroic dye is exemplified by the dichroic dye described in non-patent document 1.

[0180] The polarizing element preferably functions as a polarizing element if the ratio of the absorption amount of the axis with the strongest absorption to the absorption amount of the axis with the lowest absorption is 3 or more, that is, the dichroic ratio is 3 or more. It is more preferably 10 or more, more preferably 20 or more, particularly preferably 35 or more, and even more preferably 40 or more. In addition, the polarization degree of the polarizing element may be 30% or more, more preferably 40% or more, even more preferably 60% or more, even more preferably 80% or more, and even more preferably 90% or more.

[0181] As for the visible light absorption filter used in the present invention, when a polarizing element or a polarizing plate using the polarizing element is used, it is more preferred to use the polarizing element in a state where the axis of the weakest luminescence of the polarizing element is parallel to the axis of the highest absorbance of the polarizing element. The angles of the state where the axis of the weakest luminescence of the polarizing element is parallel to the axis of the highest absorbance of the polarizing element do not need to be completely consistent, and can be a state of parallelism for expedient display. By making the axis of the weakest luminescence of the polarizing element completely parallel to the axis of the highest absorbance of the polarizing element, the highest brightness and high contrast can be provided in the optical system of the present invention, so it is particularly preferred. Although it is actually possible to achieve a state where the axis of the weakest luminescence of the polarizing element is parallel to the axis of the highest absorbance of the polarizing element, it is more preferred to be within 10° relative to the completely parallel axes, more preferably within 5°, even more preferably within 2°, and particularly preferably within 1°.

[0182] The aforementioned optical filter is a polarizing element and satisfies the following formula (3), so that an optical system with a high contrast of polarized light emission can be obtained, which is more preferred.

[0183] A em-L-λmax ×F em-L <0.6×A Pol-Kz-em-L-λmax <0.7 Formula (3)

[0184] In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A Pol-Kz-em-L-λmax It indicates the absorbance of the polarizing element at the highest absorption axis at the wavelength with the maximum emission along the axis where the emission amount of the polarizing element is the weakest.

[0185] By satisfying the above formula (3), compared to when using a visible light absorption filter that is not a polarizing element, an optical system can be obtained that has high transmittance, high brightness at the luminous position, high luminous brightness at the extinction position, and especially significantly less luminescence at the maximum luminous wavelength at the extinction position, that is, a high-contrast optical system.

[0186] It is more preferred that the optical filter satisfies the following formula (3-a) to obtain an optical system with high brightness and low luminous brightness at the extinction position, that is, an optical system with high contrast. It is more preferred that the optical filter satisfies the following formula (3-b).

[0187] A em-L-λmax ×F em-L <0.8×A Pol-Kz-em-L-λmax <0.7 Formula (3-a)

[0188] A em-L-λmax ×F em-L <1.0×A Pol-Kz-em-L-λmax <0.7 Formula (3-b)

[0189] In the above formula (3), 0.6×A Pol-Kz-em-L-λmax The value of is preferably less than 0.6, more preferably less than 0.5, even more preferably less than 0.4, and particularly preferably less than 0.3. Through the above preferred aspects, an optical system with higher transmittance, higher brightness, and / or less luminous brightness at the extinction position can be obtained, that is, an optical system with higher contrast and / or higher transmittance can be obtained.

[0190] In a more preferred form, when the aforementioned filter is a polarizing element, an optical system can be obtained by satisfying the following formula (4) in which the light emission of the weak axis of the polarized light emitting element is reduced and the contrast of the polarized light emission is high compared to when the aforementioned filter is a non-polarizing element.

[0191] 0 <TAF em-L <0.7×TA pol -Kz-em formula (4)

[0192] Where, TA pol-Kz-em TAF represents the value obtained by integrating the absorbance of each wavelength of the polarizing element at the highest absorption axis in the wavelength range in which the polarizing element emits light. em-L The expression is the same as that of formula (2).

[0193] It is more preferable that the amount of light emitted on the weak axis of the polarized light emitting element can be further reduced by satisfying the following formula (4-a), and the optical system can display high-contrast polarized light emission.

[0194] 0 <TAF em-L <0.8×TA pol-Kz-em Formula (4-a)

[0195] It is more preferable to satisfy the following formula (4-b), and it is even more preferable to satisfy the following formula (4-c).

[0196] 0 <TAF em-L <0.9×TA pol-Kz-em Formula (4-b)

[0197] 0 <TAF em-L <1.0×TA pol-Kz-em Formula (4-c)

[0198] In the visible light absorption filter used in the present invention, the hue of the monomer obtained in accordance with JIS Z 8781-4:2013 is -5 ＊ <+3 and b ＊ <±3, a neutral color optical system can be obtained, so it is more preferred. In particular, when the polarized light emitting element has a neutral color or a high transmittance, the aforementioned filter is a neutral color, that is, a ＊ and b ＊ When the filter is a polarizing element, it can also be a monomer and the hue of the monomer is -5 ＊ <+3 and b ＊ <±3 and achieve the same effect. ＊ The value of is more preferably -3 or more and 2 or less, and even more preferably -2 or more and 1 or less. ＊ The value of is more preferably -2 or more and 2 or less, and even more preferably -1 or more and 1 or less.

[0199] In the optical system of the present invention, polarized light emitting elements and filters can be configured separately, and by stacking polarized light emitting elements and filters, an optical system with higher brightness and high transmittance can be provided, so it is more preferred. It is known that optical components generally reduce light transmittance due to interface reflection when light is incident on their interface. Therefore, in the optical system of the present invention, in order to obtain an optical system with high brightness and high transmittance, it is important to reduce the interface and reduce the interface reflection on the optical path of the optical system. Therefore, stacking polarized light emitting elements and polarized elements is a more preferred form.

[0200] ​​In addition, in one form of the present invention, a medium for controlling the phase may be provided in the above-mentioned optical system. The so-called medium having a phase may include a phase difference plate (also called a wavelength plate, a phase difference film), and may also include a liquid crystal panel (liquid crystal unit) that electrically drives and regulates the liquid crystal. In particular, since a liquid crystal display device can be obtained by using a liquid crystal panel (liquid crystal unit) that can electrically control the phase as a medium for controlling the phase, it is a more preferred form of the present invention. When using the optical system of the present invention, since the polarized light-emitting element will emit light, a self-luminous liquid crystal display can be made, and since a liquid crystal display with high transmittance and high contrast can be obtained, a display device with very high transmittance and high contrast compared to a liquid crystal display using a general polarizing plate can be obtained. Generally speaking, a liquid crystal display uses two polarizing plates, but the parallel transmittance when two plates are used is 25 to 35%. The liquid crystal display using the well-known polarizing plate with a parallel transmittance of 25 to 35% has low quality as a see-through display due to its low transmittance. In addition, since it is not self-luminous, a backlight must be provided, but since the backlight unit uses CCFL or LED, transparency cannot be obtained. In contrast, the polarized light-emitting element used in the optical system of the present invention is transparent and luminous, so it can be used as a transparent and self-luminous liquid crystal display device.

[0201] In addition, by using a medium with a phase, when polarized light is presented as a wave having the properties of particles and waves, the phase of the wave can be controlled. When focusing on polarized light, for example, a wavelength plate is an optical functional element that gives a predetermined phase difference to linearly polarized light, and polarized light can be set with different phases on other axes (for example, 90°) for light of a specific axis. That is, by setting a wavelength plate on the optical path of a polarized light, it can be converted into polarization of the opposite axis and re-assigned with circular polarization, elliptical polarization, etc. The wavelength plate can be said to be an element that uses an oriented birefringent material (such as a stretched film) to give a phase difference to two orthogonal polarization components, thereby changing the polarization state of the incident light. The specific use of the wavelength plate is, for example, when the wavelength of a specific light is set to λ, the slow axis of the λ / 2 phase difference plate is set to 45° relative to the axis of polarization, thereby allowing the linear polarization incident on the wavelength plate (phase difference plate) to be rotated 90° and emitted as polarization having a polarization axis in a direction orthogonal (90°) to the incident polarization axis. In addition, when the angle of the axis is set to 45° relative to the axis of the polarized light as the purpose, although the function of the phase difference plate to a certain extent is manifested even if it is offset by about ±10°, it is more preferably in the range of ±5°, more preferably in the range of ±3°, and even more preferably in the range of ±2°, and particularly preferably in the range of ±1°. In addition, when the slow axis of the λ / 4 phase difference plate is set to 45° relative to the axis of polarization, the linear polarization incident on the wavelength plate (phase difference plate) can be emitted as circularly polarized light.

[0202] The optical system of the present invention made in this way shows polarized light luminescence effect and high transmittance in the visible light region, that is, an optical system with high brightness and high contrast. In addition, the optical system of the present invention shows excellent durability for heat, humidity, light, etc., so its performance can also be maintained under harsh environments, and it has higher durability than the more familiar iodine-based polarizer. Therefore, the optical system of the present invention can not only be effectively used for lenses, glasses, and liquid crystal displays requiring high transparency in the visible light region and high durability under harsh environments, and liquid crystal displays, for example, as televisions, wearable terminals, desktop terminals, smart phones, car screens, perspective displays, and various display devices such as electronic billboards, smart windows used outdoors or indoors, and liquid crystal display orientations with high efficiency polarized backlights, can also be applied to polarized light sources that can emit light efficiently, etc.

[0203] (Display device)

[0204] In the present invention, when a specific polarized light emitting pigment is used, the polarized light emitting effect is displayed by irradiating light in the visible light region from ultraviolet to near ultraviolet (specifically, irradiating light of 300 to 430nm), and the display can be displayed by utilizing this effect. The display device of the present invention has a high transmittance in the visible light region, so the decrease in transmittance in the visible light region of the well-known polarizing plate can be significantly reduced. In particular, because the display device having the optical system of the present invention has high transparency, a display that is a liquid crystal display but is roughly transparent can be obtained. In addition, because it can be designed so that even when displaying text, images, etc., the environment and images on the back can be recognized from the viewing side through the display device, a display that is transparent and can recognize the back can be obtained, that is, a display that is transparent but can display text, etc. can be obtained. Moreover, the display device of the present invention is effective in application as a transparent liquid crystal display without light loss, especially a perspective display.

[0205] In addition, the display device of the present invention can be used to produce a liquid crystal display, for example, which displays polarized light by irradiating ultraviolet light and uses the polarized light to emit light. Therefore, a liquid crystal display that does not use visible light, but uses invisible light using ultraviolet light, can be realized. In other words, a self-luminous liquid crystal display can be produced, which can display the desired text, image, etc. even in a dark space without light, if it is a space that can be irradiated with ultraviolet light.

[0206] In a vehicle or outdoor display liquid crystal display using the optical system of the present invention, the liquid crystal unit used is not limited to TN liquid crystal, STN liquid crystal, VA liquid crystal, IPS liquid crystal, etc., and the liquid crystal display can be used in all liquid crystal display modes.

[0207] The optical system of the present invention has excellent polarized light emitting performance, and can suppress discoloration and reduction of polarized light emitting performance even under high temperature and high humidity conditions inside or outdoors. Therefore, it can be helpful to improve the long-term reliability of liquid crystal displays for vehicles or outdoor displays.

[0208] [Example]

[0209] Hereinafter, the present invention will be described in more detail by way of examples, but these are illustrative examples and are not intended to limit the present invention. In addition, the "%" and "parts" described below are by weight unless otherwise specified. In addition, in each structural formula of the compound used in each example and comparative example, acidic functional groups such as sulfonic acid are recorded in the form of free acid.

[0210] [Evaluation method]

[0211] Each polarized light emitting element or polarized light emitting plate obtained in the following Examples and Comparative Examples was used as a measurement sample and evaluated in the following manner.

[0212] [Determination of penetration rate]

[0213] The transmittance and absorbance of the polarized light emitting element, polarized light emitting plate, polarized element, polarized plate and optical system were evaluated using a spectrophotometer ("U-4100" manufactured by Hitachi High Technologies). A Gram Thomson polarizer was provided to irradiate each polarized light emitting element (measurement sample) produced in each embodiment and comparative example with 100% polarized light (hereinafter also referred to as "absolute polarization") in the wavelength region of 220 nm to 2600 nm, and the transmittance of each wavelength of light when the measurement sample was irradiated with absolute polarization was measured.

[0214] [Photometric correction single transmittance Ys, photometric correction orthogonal transmittance Yc]

[0215] For a polarized light emitting element, a polarized light emitting plate, a polarizing element, a polarizing plate or an optical system, the transmittance of light measured when polarized light is incident in an orthogonal position relative to the axis of the light absorption that is highest through the orientation of the pigment when irradiating the absolute polarized light (that is, the transmittance of light of the axis with the least absorption when the absolute polarized light is incident) is set to Ky, and the transmittance of light measured when polarized light is incident in a parallel position relative to the axis of the light absorption that is highest through the orientation of the pigment when irradiating the polarized light emitting element or the polarizing element (that is, the transmittance of light of the axis with the most absorption when the absolute polarized light is incident) is set to Kz. In addition, Ky in the polarized light emitting element shows the transmittance of light of the axis with the weakest light emission, and Kz in the polarized light emitting element shows the transmittance of light of the axis with the strongest light emission. The photometrically corrected single transmittance Ys and photometrically corrected orthogonal transmittance Yc of each measured sample are obtained by substituting the above Ky and Kz obtained for each predetermined wavelength interval dλ (5 nm in this case) into formula (I) to calculate the single transmittance Ts of each wavelength, and into formula (II) to calculate the single transmittance Tc of each wavelength, and correcting them into photometric transmittance in accordance with JIS Z 8722:2009. Specifically, the photometrically corrected single transmittance Ys is calculated by substituting the single transmittance Ts of each wavelength into the following formula (III), and the photometrically corrected orthogonal transmittance Yc is calculated by substituting the orthogonal transmittance Tc of each wavelength into the following formula (IV). In the following formula (III) or (IV), Pλ represents the spectral distribution of the standard light (C light source), and yλ represents the two-dimensional field of view color matching function. The photometrically corrected single transmittance Ys indicates the transmittance when viewed as a single body, and the photometrically corrected orthogonal transmittance Yc indicates the transmittance when two measurement samples are viewed orthogonally.

[0216] Ts=(Ky+Kz) / 2 (I)

[0217] Tc=(Ky×Kz) / 100 (II)

[0218]

[0219] (Chroma ＊ Value and b ＊ value)

[0220] For each test sample, the chromaticity a of the single-unit transmittance Ts was measured in accordance with JIS Z 8781-4:2013. ＊ Value and b ＊ The above-mentioned spectrophotometer was used to measure the transmittance of each wavelength, and the light source used was a C 2° field of view. ＊ -s and b ＊ -s respectively correspond to the chromaticity a when the monomer transmittance Ts is measured＊ Value and b ＊ value.

[0221] (Absorbance)

[0222] The absorbance (Abs) at each wavelength in each axis of each measurement sample was determined using Tr obtained by substituting the above Ky and Kz into the following formula (V).

[0223] Abs=-Log(Tr) (V)

[0224] (Quantum yield of polarized light emitting element)

[0225] The quantum yield of each axis of the polarized light emitting element is a value obtained by using FP-8500 manufactured by JASCO Corporation as a measured value. Specifically, when the quantum yield of the polarized light emitting element is measured by FP-8500 manufactured by JASCO Corporation, the quantum yield obtained by irradiating the axis showing the highest light absorption through the polarized axis by the orientation of the polarized light emitting pigment and the quantum yield obtained by irradiating the axis showing the lowest light absorption through the polarized axis by the orientation of the polarized light emitting pigment are measured in such a manner that polarized light can be incident on the polarized light emitting element, as the quantum yield of the polarized light emitting element of the present invention.

[0226] (Emission intensity of each wavelength of the polarized light emitting element and degree of polarization (DOP) of the emitted light)

[0227] The luminous intensity of each wavelength of the polarized light emitting element and the degree of polarization (DOP) of the emitted light are measured using the values ​​obtained by the Stokes parameter method. Specifically, the values ​​measured using a spectropolarimeter (Poxi-Spectra, a spectropolarimeter manufactured by Tokyo Instruments). In addition, the types (states) of polarized light emission of the polarized light emitting elements or polarized light emitting plates used in the following embodiments or comparative examples confirmed using the spectropolarimeter Poxi-Spectra manufactured by Tokyo Instruments are all linearly polarized.

[0228] (Production of Polarized Light Emitting Element A)

[0229] A polyvinyl alcohol film (VF-PS#7500 manufactured by KURARAY) with a thickness of 75 μm was immersed in warm water at 40°C for 3 minutes to swell the film. The swollen film was immersed in a 45°C aqueous solution containing 0.8 parts by weight of an aqueous solution of 4,4'-bis-(sulfonylphenyl)biphenyl disodium (Tinopal NFW Liquid manufactured by BASF) described in formula (B-1), 1.0 parts by weight of sodium sulfate, and 1500 parts by weight of water for 4 minutes. After immersion, the obtained film was stretched for 5 minutes in a 3% boric acid aqueous solution at 50°C to a length that was 5 times that of the film. The stretched film was kept in its original stretched state and washed with water at room temperature for 20 seconds, and then dried at 70°C for 9 minutes to obtain a polarized light-emitting element A. The order parameter of the polarized light-emitting element A calculated according to the above formula (5) is 0.91, and the wavelength of maximum absorption is 375nm. When the polarized light emitting element A is irradiated with ultraviolet rays and its light emission is confirmed through a general polarizing plate (SKN-18243P manufactured by POLATECHNO), blue polarized light is emitted in the direction of the stretching axis when the polarized light emitting element is processed, and on the other hand, the polarized light emission is significantly lower in the orthogonal axis relative to the stretching axis. In other words, the polarized light emitting element is an element that emits linear polarization.

[0230] (Production of Polarized Light Emitting Plate A Using Polarized Light Emitting Element A)

[0231] A triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) containing no ultraviolet absorber was treated with a 1.5-normal sodium hydroxide aqueous solution at 35°C for 10 minutes, washed with water, and then dried at 70°C for 10 minutes. A triacetyl cellulose film (hereinafter referred to as TAC) treated with alkali was laminated on both sides of the polarized light-emitting element A via an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL Co., Ltd. of Japan), and dried at 70°C for 10 minutes to prepare a polarized light-emitting plate A having a structure of TAC / polarized light-emitting element A / TAC. The obtained polarized light-emitting plate A has the characteristics of the polarized light-emitting element A without impairing the optical characteristics of the obtained polarized light-emitting element A.

[0232] (Production of Polarized Light Emitting Element B and Polarized Light Emitting Plate B)

[0233] Polarized light-emitting element B and polarized light-emitting plate B are prepared in the same manner, except that 0.05 parts by weight of the aqueous solution of the compound described in formula (B-1) is used to replace 0.8 parts by weight of the aqueous solution of the compound described in formula (B-1) in the preparation of polarized light-emitting element A and polarized light-emitting plate A. The order parameter of polarized light-emitting element B calculated by the above formula (5) is 0.84, and the maximum wavelength of absorption is 380nm. When the polarized light-emitting plate B is irradiated with ultraviolet rays and its luminescence is confirmed through a general polarizing plate (SKN-18243P manufactured by POLATECHNOL), blue polarized light is emitted in the direction of the extension axis when the polarized light-emitting element is processed. On the other hand, the polarized light is significantly lower in the orthogonal axis relative to the extension axis. In other words, the polarized light-emitting element is an element that emits linear polarized light.

[0234] (Synthesis example 1)

[0235] 35.2 parts of commercially available 4-diamino-stilbene-2,2'-disulfonic acid were added to 300 parts of water and stirred, and 35% hydrochloric acid was used to adjust the pH to 0.5. 10.9 parts of 40% sodium nitrite aqueous solution were added to the obtained solution, and stirred at 10°C for 1 hour, followed by 34.4 parts of 6-aminonaphthalene-2-sulfonic acid, and the pH was adjusted to 4.0 with 15% sodium carbonate aqueous solution, and stirred for 4 hours. 60 parts of sodium chloride were added to the obtained reaction solution, and the precipitated solid was separated by filtration, and then washed with 100 parts of acetone and dried to obtain 62.3 parts of the compound described in the following formula (S-7p).

[0236]

[0237] 62.3 parts of the compound of formula (S-7p) obtained above were added to 300 parts of water and stirred, and a 25% sodium hydroxide aqueous solution was used to adjust the pH to 10.0. 20 parts of 28% ammonia water and 9.0 parts of copper sulfate pentahydrate were added to the obtained solution, and stirred at 90°C for 2 hours. 25 parts of sodium chloride were added to the obtained reaction solution, and the precipitated solid was filtered and separated, and then washed with 100 parts of acetone to obtain 40.0 parts of wet cake, and the wet cake was dried in a hot air dryer at 80°C to obtain 20.0 parts of the polarized light emitting pigment represented by formula (S-7).

[0238] (Manufacturing of Polarized Light Emitting Element C and Polarized Light Emitting Plate C)

[0239] Polarized light emitting element C and polarized light emitting plate C were prepared in the same manner, except that 0.1 parts by weight of the polarized light emitting pigment represented by formula (S-7) was used to replace 0.8 parts by weight of the aqueous solution of the compound described in formula (B-1) as the polarized light emitting pigment in the preparation of polarized light emitting element A and polarized light emitting plate A. The order parameter of polarized light emitting element C calculated by the above formula (5) is 0.84, and the wavelength of maximum absorption is 400nm. When the polarized light emitting plate C is irradiated with ultraviolet rays and its luminescence is confirmed through a general polarizing plate (SKN-18243P manufactured by POLATECHNOL), blue polarized light is emitted in the direction of the extension axis when the polarized light emitting element is processed. On the other hand, the polarized light is significantly lower in the orthogonal axis relative to the extension axis. In other words, polarized light emitting element C is an element that emits linear polarized light.

[0240] The Ky and Kz of each wavelength in the polarized light emitting plates A to C were measured every 5 nm using a spectrophotometer ("U-4100" manufactured by Hitachi High Technologies) and are shown in FIG. Figure 1 The luminous intensity ratio of each wavelength of polarized light emitting plates A to C measured by a spectropolarimeter (Poxi-Spectra manufactured by Tokyo Instruments Co., Ltd.) when the intensity of the luminous wavelength showing the maximum value is set to 1 is expressed as Figure 2 The polarization degree (DOP) of the wavelengths showing a maximum value in the emitted light of the polarized light emitting plates A to C is expressed as 1, and the luminous intensity of each wavelength is 0.05 or more. Figure 3 .

[0241] Table 1 shows the light intensity correction single body transmittance (Ys- em ), maximum absorption wavelength (λmax-A em ), the absorbance (A) of the wavelength of maximum absorption on the axis where the amount of light absorbed by the polarized light emitting plate showing the maximum absorption wavelength is the highest em-H-λmax ), the value after the absorbance of each wavelength on the axis that makes the light absorption of the polarized light emitting plate the highest is integrated in the light absorption wavelength range (TA em-H ), the quantum yield of the axis where the polarized light emitting plate absorbs the most light (F em-H ), the absorbance of the polarized light emitting plate showing the maximum absorption wavelength is the wavelength of the maximum absorption of the lowest axis (A em-L-λmax ), the value after integrating the absorbance of each wavelength on the axis where the light absorption of the polarized light emitting plate is the lowest in the light absorption wavelength range (TA em-L ), the quantum yield of the axis where the light absorption of the polarized light emitting plate is the lowest (F em-L ), maximum emission wavelength (λmax-EMem ), emission wavelength range (Range-EM em ).

[0242] Table 2 shows the absorbance (A) at the wavelength of the maximum absorption of the axis where the light absorption of the polarized light emitting plate is the highest, measured every 5 nm. em-H-λmax ) and the quantum yield (F em-H ), the product of the absorbance at each wavelength of the axis where the light absorption of the polarized light emitting plate is the highest and the quantum yield of the axis where the light absorption of the polarized light emitting plate is the highest, accumulated over the light absorption wavelength range of the polarized light emitting plate (TAF em-H ), the absorbance of the wavelength of the maximum absorption of the axis where the light absorption of the polarized light emitting plate is the lowest (A em-L-λmax ) and the quantum yield (F em-L ), the product of the absorbance of each wavelength of the axis where the light absorption of the polarized light emitting plate is the lowest and the quantum yield of the axis where the light absorption of the polarized light emitting plate is the lowest, accumulated over the light absorption wavelength range of the polarized light emitting plate (TAF em-L ).

[0243] [Table 1]

[0244]

[0245] [Table 2]

[0246]

[0247] from Figure 1 From the results shown in Table 1 and Table 2, it can be seen that polarized light plate A absorbs light below about 425nm, polarized light plate B absorbs light below about 405nm, and polarized light plate C absorbs light below 440nm, and has anisotropic absorption of light axis, that is, has polarization function. Figure 2 , Figure 3 The results show that polarized light emitting plates A and B emit light at 400 to 570 nm, and polarized light emitting plate C emits light at 430 to 600 nm, and the light emitted by each polarized light emitting plate has a high degree of polarization (DOP).

[0248] (Manufacturing of Polarizing Element A and Polarizing Plate A)

[0249] According to the method of Example 1 of Patent Document 7, a polyvinyl alcohol film (VF-PS#7500 manufactured by KURARAY Co., Ltd.) with a thickness of 75 μm was immersed in warm water at 45° C. for 2 minutes, and a swelling treatment was applied to set the stretching ratio to 1.30 times. In the dyeing step, the film subjected to the swelling treatment was immersed in a 45° C. solution containing 2000 parts by weight of water, 2.0 parts by weight of anhydrous sodium sulfate, 0.34 parts by weight of an azo compound described in Synthesis Example 1 of International Publication No. WO2012 / 165223, 0.027 parts by weight of an azo compound described in Synthesis Example 1 of Japanese Patent Laid-Open No. 2003-215338, 0.040 parts by weight of an azo compound described in Example 1 of Japanese Patent No. 2622748, and 0.16 parts by weight of CI Direct Orange 39 for 1 minute and 00 seconds, so that the film contains the azo compound. The obtained film was immersed in a 40°C aqueous solution containing 20 g / l of boric acid (manufactured by Societa Chimica Larderello spa) for 1 minute. The obtained film was stretched 5.0 times and stretched in a 50°C aqueous solution containing 30.0 g / l of boric acid for 5 minutes. The obtained film was kept in a taut state and treated with 25°C water for 20 seconds. The obtained film was dried at 70°C for 9 minutes to obtain a polarizing element A of a type of visible light absorption filter. A triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) without an ultraviolet absorber was treated with a 1.5 equivalent sodium hydroxide aqueous solution at 35°C for 10 minutes, washed with water, and then dried at 70°C for 10 minutes. The triacetyl cellulose film obtained by alkali treatment was laminated on both sides of the polarizing element A through an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL Co., Ltd., Japan), dried at 70°C for 10 minutes, and an anti-reflection layer (AR layer) was provided on the surface to form a polarizing plate A, which is one of the forms of a visible light absorption filter and has a structure of AR layer / TAC / polarizing element A / TAC / AR layer. The obtained polarizing plate A has the characteristics of the polarizing element A without impairing the optical characteristics of the obtained polarizing element A.

[0250] (Production of Polarizing Element B and Polarizing Plate B)

[0251] A polarizing element B and a polarizing plate B, which are one form of a visible light absorption filter, were obtained in the same manner as in the preparation of the polarizing element A except that the immersion time in the aqueous solution containing the azo compound was changed to 2 minutes.

[0252] (Manufacturing of Polarizing Element C and Polarizing Plate C)

[0253] A polarizing element C and a polarizing plate C, which are one form of a visible light absorption filter, were obtained in the same manner as in the preparation of the polarizing element A except that the immersion time in the aqueous solution containing the azo compound was changed to 3 minutes.

[0254] <Production of Polarizing Element D and Polarizing Plate D>

[0255] Polarizing element D and polarizing plate D, which are one of the forms of the optical filter absorbing visible light region used in the present application, were prepared in the same manner except that a polyvinyl alcohol film (VF-PS#7500 manufactured by KURARAY Co., Ltd.) having a thickness of 75 μm was immersed in warm water at 40° C. for 3 minutes to swell the film, and the swollen film was immersed in a 45° C. aqueous solution containing 0.04 parts by weight of the azo compound described in Example 1 of Patent Document 8, 1.0 parts by weight of sodium sulfate, and 1500 parts by weight of water for 4 minutes. The obtained polarizing plate D has the characteristics of polarizing element D without impairing the optical characteristics of the obtained polarizing element D.

[0256] <Production of Polarizing Element E and Polarizing Plate E>

[0257] Polarizing element E and polarizing plate E, which are one form of a visible light absorption filter, were prepared in the same manner except that a polyvinyl alcohol film (VF-PS#7500 manufactured by KURARAY Co., Ltd.) having a thickness of 75 μm was immersed in warm water at 40° C. for 3 minutes to swell the film, and the swollen film was immersed in a 45° C. aqueous solution containing 0.03 parts by weight of the azo compound described in Synthesis Example 1 of JP-A-2003-215338, 1.0 parts by weight of sodium sulfate, and 1500 parts by weight of water for 4 minutes. The obtained polarizing plate E has the characteristics of polarizing element E without impairing the optical characteristics of the obtained polarizing element E.

[0258] A visible light absorption filter F having a transmittance of about 70% at each wavelength in the visible light region and having both surfaces of a laminate that can be bonded / joined was produced by the following method.

[0259] 0.095 parts of KAYASETBLACK AN (manufactured by Nippon Kayaku Co., Ltd.) and 0.0048 parts of KAYASET BLUE AD (manufactured by Nippon Kayaku Co., Ltd.) were mixed with 100 parts of the resin solid content of the adhesive PTR-3000 manufactured by Nippon Kayaku Co., Ltd., and methyl ethyl ketone was added so that the solid content content was 17 parts per 100 parts of the prepared composition, and mixed for 1 hour to prepare an adhesive composition for an optical filter. The obtained adhesive composition for an optical filter was sandwiched between two release films (polyethylene terephthalate films) using a coater to form a sheet with a thickness of 25 μm, thereby preparing an optical filter F.

[0260] A neutral density filter ND-0.1 (manufactured by Fuji Film Co., Ltd.) was used as the visible light absorption filter G having a transmittance of 80% at each wavelength in the visible light region.

[0261] A visible light absorption filter H was produced by the following method. The laminated body had a transmittance of about 90% at each wavelength in the visible light region and was bonded to both sides.

[0262] With respect to 100 parts of the resin solid content of the adhesive PTR-3000 manufactured by Nippon Kayaku Co., Ltd., 0.0092 parts of KAYASET BLACK AN (manufactured by Nippon Kayaku Co., Ltd.) and 0.001 parts of KAYASET BLUE AD (manufactured by Nippon Kayaku Co., Ltd.) were mixed and stirred to obtain a prepared composition, and methyl ethyl ketone was added so that the solid content content was 17 parts with respect to 100 parts of the prepared composition, and mixed for 1 hour to prepare an adhesive composition for an optical filter. The obtained adhesive composition for an optical filter was sandwiched between two release films (polyethylene terephthalate films) using a coater and formed into a sheet with a thickness of 25 μm, thereby preparing an optical filter H.

[0263] As the visible light absorption filter used in the comparative example, SKN-18243P (hereinafter referred to as polarizing plate I), which is a general iodine-based polarizing plate having a transmittance of 43% manufactured by POLATECHNO, was used.

[0264] exist Figure 4 The Ky and Kz of polarizing plates A, B, C, D, and E measured every 5 nm are shown in Table 1. Figure 5 : Shown in the figure are the transmittances per 20 nm of the filter F sandwiched by TAC films, the filter H sandwiched by TAC films, and the filter G not sandwiched by TAC films, which were measured every 5 nm.

[0265] Table 3 shows the photometrically corrected single transmittance (Ys- fi ), photometric correction orthogonal transmittance (Yc- fi ), the hue of the monomer (a ＊ -s and b ＊ -s), the absorbance of the monomer at 435 nm (A fi-em-435 ), the absorbance at 465 nm of the monomer (A fi-em-465), the value of the thickness after the absorption of the monomer at each wavelength from 400 to 570nm (TA fi-em 400-570 ), the value after integrating the absorbance of the monomer at each wavelength from 430 to 600 nm (TA fi-em 430-600 ), the absorbance at 435 nm of the axis with the strongest absorption (A pol-Kz-em-L-435 ), the absorbance at 465 nm of the axis with the strongest absorption (A pol-Kz-em-L-465 ), the value after integrating the absorbance at each wavelength of the axis with the strongest absorption from 400 to 570 nm (TA pol-Kz-em-400-570 ), the value after the absorption of each wavelength is integrated at the axis with the strongest absorption from 430 to 600 nm (TA pol-Kz-em-430-600 ).

[0266] [Table 3]

[0267]

[0268] Table 4 shows the photometrically corrected single transmittance (Ys- fi ), the hue of the monomer (a ＊ -s and b ＊ -s), absorbance at 435nm (A fi-em-435 ), absorbance at 465 nm (A fi-em-465 ), the value after the absorption of each wavelength of the filter from 400 to 570nm is integrated (TA fi-em 400-570 ), and the value after the absorption of each wavelength of the filter from 430 to 600 nm is integrated (TA fi-em 430-600 In addition, because filter F, filter G, and filter H are not polarizers, the photometric correction cross transmittance (Yc- fi ).

[0269] [Table 4]

[0270]

[0271] from Figure 4 , Figure 5 It can be seen that the visible light absorption filter used in the present application has the function of absorbing light for the wavelengths of light emitted by polarized light emitting plates A to C. In addition, polarized plates A to E have axial absorption anisotropy of light for the wavelengths emitted by polarized light emitting plates A to C, that is, they have polarization characteristics. When polarized plates A to E have a photometric correction monomer transmittance that is approximately the same as that of filter F with a transmittance of 70%, filter G with a transmittance of 80%, and filter H with a transmittance of 90%, the absorbance of the axis showing the strongest absorption is high.

[0272] From Table 3 and Table 4, we can see that the polarizers A to C and filters F to H have a ＊ -s, b ＊ -s also has the highest absolute value within 2.072. In particular, the a values ​​of polarizers A to C are ＊ -s, b ＊ The absolute value of -s is less than 1, which means it has a neutral hue.

[0273] (Production of Polarizing Plate J for Ultraviolet Region)

[0274] A polyvinyl alcohol film (VF-PS#7500 manufactured by KURARAY Co., Ltd.) with a thickness of 75 μm was immersed in warm water at 40° C. for 3 minutes to swell the film. The swollen film was immersed in an aqueous solution containing 0.8 parts of CI Direct Yellow 28, 1.0 parts of Glauber's Salt, and 1500 parts of water at 45° C. for 5 minutes to contain the solution. The obtained film was immersed in a 3% boric acid aqueous solution at 50° C. for 5 minutes and stretched to 5 times. The stretched film was kept in the original tight state and washed with water at room temperature for 20 seconds, and dried at 70° C. for 9 minutes to obtain a polarizing element for the ultraviolet region. On the other hand, both sides of a triacetyl cellulose film containing no ultraviolet absorber (ZRD-60 manufactured by Fuji Film Co., Ltd.) were treated with a 1.5 equivalent sodium hydroxide aqueous solution at 35°C for 10 minutes, washed with water, and dried at 70°C for 10 minutes, laminated on both sides of the produced polarizing element for the ultraviolet region via an aqueous solution containing 4% of a polyvinyl alcohol resin (NH-26 manufactured by Japan VAM&POVAL Co., Ltd.), dried at 70°C for 8 minutes, and an anti-reflection layer (AR layer) was provided on the surface to obtain a polarizing plate J for the ultraviolet region having a structure of AR layer / TAC / polarizing element for the ultraviolet region / TAC / AR layer and a light intensity correction monomer transmittance of 90.26%.

[0275] Table 5 shows: Ky, Kz, single transmittance Ts, orthogonal transmittance Tc, polarization degree ρ, and photometrically corrected single transmittance (Ys) obtained by measuring every 5 nm of the obtained polarizing plate J for ultraviolet region at 375 nm and its λmax (405 nm); Figure 6 The following table shows the Ky and Kz of each wavelength of the polarizing plate for the ultraviolet region. Figure 6 It is known that the polarizing plate for ultraviolet region used in the present application has high polarization characteristics in the range of 350 to 450 nm.

[0276] [Table 5]

[0277]

[0278] <Example 1>

[0279] The polarized light emitting plate A and the filter G (neutral density filter ND-0.1 manufactured by Fuji Film Co., Ltd.) were bonded together with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) to form the optical system of the present invention. As shown in Tables 1, 2, and 4, the optical system satisfies formula (2).

[0280] <Example 2>

[0281] The polarized light emitting plate A, the filter F with adhesive function, and TAC are bonded in this order to form the optical system of the present invention. As can be seen from Tables 1, 2, and 4, the optical system satisfies equations (1) and (2).

[0282] <Example 3>

[0283] The optical system of the present invention is formed by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a way that the axis with the highest light absorption of the polarizing plate A (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate A (the orientation axis of the dichroic pigment) are orthogonal. From Table 1, Table 2 and Table 3, it can be seen that the optical system satisfies equations (2), (3) and (4).

[0284] <Example 4>

[0285] The optical system of the present invention is formed by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate A (the orientation axis of the polarizing light emitting pigment) and the axis with the highest light absorption of the polarizing plate D (the orientation axis of the dichroic pigment) are orthogonal. From Table 1, Table 2 and Table 3, it can be seen that the optical system satisfies equations (1), (2), (3) and (4).

[0286] <Example 5>

[0287] The optical system of the present invention is obtained by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate B (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate B (the orientation axis of the dichroic pigment) are orthogonal. From Table 1, Table 2 and Table 3, it can be seen that the optical system satisfies equations (1), (2), (3) and (4).

[0288] <Example 6>

[0289] The optical system of the present invention is obtained by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate B (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate A (the orientation axis of the dichroic pigment) are orthogonal. From Tables 1, 2, and 3, it can be seen that the optical system satisfies equations (1), (2), (3), and (4).

[0290] <Example 7>

[0291] The optical system of the present invention is formed by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate B (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate D (the orientation axis of the dichroic pigment) are orthogonal. From Table 1, Table 2 and Table 3, it can be seen that the optical system satisfies equations (1), (2), (3) and (4).

[0292] <Example 8>

[0293] The optical system of the present invention is obtained by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate C (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate C (the orientation axis of the dichroic pigment) are orthogonal. From Tables 1, 2, and 3, it can be seen that the optical system satisfies equations (1), (2), (3), and (4).

[0294] <Example 9>

[0295] The optical system of the present invention is obtained by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a manner that the axis with the highest light absorption of the polarizing plate C (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate B (the orientation axis of the dichroic pigment) are orthogonal. From Tables 1, 2, and 3, it can be seen that the optical system satisfies equations (1), (2), (3), and (4).

[0296] <Example 10>

[0297] The optical system of the present invention is formed by bonding the two plates with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a way that the axis with the highest light absorption of the polarizing plate A (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of the polarizing plate E (the orientation axis of the dichroic pigment) are orthogonal. From Table 1, Table 2 and Table 3, it can be seen that the optical system satisfies equations (2) and (4).

[0298] <Comparative Example 1>

[0299] Only the polarized light emitting plate A was used as a sample of Comparative Example 1 without a visible light absorption filter.

[0300] <Comparative Example 2>

[0301] The polarized light emitting plate A, the filter H with adhesive function, and TAC are sequentially attached to form an optical system. From Table 1, Table 2, and Table 3, it can be seen that the optical system does not satisfy equations (1) and (2).

[0302] <Comparative Example 3>

[0303] Only the polarized light emitting plate B was used as a sample of Comparative Example 3 without a visible light absorption filter.

[0304] <Comparative Example 4>

[0305] The two plates were bonded together with an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.) in such a way that the axis with the highest light absorption of polarizing plate B (the orientation axis of the polarizing pigment) and the axis with the highest light absorption of polarizing plate I (iodine-based polarizing plate SKN-18243P) were orthogonal to prepare a sample for comparison example.

[0306] <Comparative Example 5>

[0307] Only the polarized light emitting plate C was used as a comparative sample without a visible light absorption filter.

[0308] For the optical systems obtained in Examples 1 to 10 and the samples obtained in Comparative Examples 1 to 5, a 375nm LED light source (LED M375L4° with a mounting base manufactured by THORLABS) was used as a light source. In addition, a liquid crystal cell was used as a medium for controlling the phase, and the light source, the polarizing plate J for the ultraviolet region, the liquid crystal cell, the optical system of the present invention, or the comparative sample were sequentially arranged to produce a display device capable of polarized light emission. The optical systems of Examples 3 to 10 or the samples of Comparative Examples 1 and Comparative Examples 3 to 5 were bonded in such a manner that the polarized light emitting plate was located on the liquid crystal cell side, and the polarized light from the polarizing plate J for the ultraviolet region was irradiated to the polarized light emitting plate side through the liquid crystal cell. The optical systems of Examples 1 and 2 and Comparative Example 2 were bonded in such a manner that the polarized light emitting plate, the filter, and the TAC were bonded to the liquid crystal cell in such a manner that the polarized light from the polarizing plate J for the ultraviolet region was irradiated to the side of each polarized light emitting plate.

[0309] In the obtained polarized light emitting display device, the display device using the optical system of Examples 1 to 10 and the sample of Comparative Examples 1 to 5 is used as the object, and the light from the ultraviolet region to the near ultraviolet visible light region is irradiated from a 375nm LED light source via a polarizing plate J in the ultraviolet region, and the luminous intensity (brightness) of the bright state and the dark state when the liquid crystal unit is driven is measured using a 2-dimensional color brightness meter (ProMetric IC-PMI2 manufactured by KONICAL MINOLTA Co., Ltd.). In addition, the liquid crystal unit uses a liquid crystal unit in which a liquid crystal (ZLI-1083 manufactured by MERCK) is enclosed in a liquid crystal empty unit (KSRS-05 / B111M1NSS05 manufactured by EHC) is enclosed. The luminous intensity (brightness) of each bright state and dark state in the present application is evaluated as the value when there is no applied voltage (0V) and when an applied voltage of 4V is applied.

[0310] Table 6 shows the light intensity correction single body transmittance (Ys- sys ), the hue of the liquid crystal unit (a ＊ -s, b ＊ -s), and the luminance of a display device capable of polarized light emission using the liquid crystal unit in a bright state (EM- SYS-H ), dark state luminescence brightness (EM- SYS-L ), contrast between the bright state and the dark state (CR- SYS ).

[0311] [Table 6]

[0312]

[0313] From the results in Table 6, it can be seen that the display device using the optical system satisfying the above formula (1) or / and the above formula (2) has a light correction monomer transmittance of more than 50% and displays a high contrast. ＊ -s, b ＊-s) is a hue with a neutral color, it can be seen that the liquid crystal unit and the display device using the optical system of the present invention also have a neutral color. In addition, by comparing Example 1 with Example 3, it can be seen that although a visible light absorption filter with the same light intensity correction monomer transmittance is provided, in the case where the visible light absorption filter is a polarizing plate as in Example 3, the display device using the optical system of the present invention has a high transmittance and a high contrast. Compared with Comparative Example 1, Comparative Example 3, and Comparative Example 5 using only a polarizing light-emitting plate, or using a filter with a transmittance of 90% that does not satisfy Formula (1) and Formula (2), the contrast of the display device in these embodiments is significantly high, which shows the superiority of the optical system of the present invention. In addition, from the comparison of Examples 5 to 7 with Comparative Example 4, it can be seen that a display device with a high transmittance and a high luminous brightness can be obtained compared to the case of using a general polarizing plate.

[0314] [Industrial Applicability]

[0315] The optical system of the present invention can provide high contrast when emitting polarized light. In one aspect, the optical system of the present invention can improve the contrast of the luminous brightness of each axis of the film, and has a high transmittance in the visible light region. Therefore, in one aspect, the optical components and display devices such as lenses of the optical system of the present invention have high transparency in the visible light region and can display images by polarized light emission, so they can be applied to a wide range of uses such as televisions, personal computers, tablet terminals, lenses, and further perspective displays (See through display). In addition, because it can emit light by ultraviolet light, in one aspect, the polarized light emitting element and polarized light emitting plate of the present invention can also be applied to functional media such as displays and sensors that are required to have high safety, and the functional medium is required to be able to show function by irradiating non-visible light such as ultraviolet light that is difficult to recognize with human eyes.

Claims

1. An optical system comprising a polarized light emitting element and a filter, wherein: The polarized light emitting element absorbs light of a wavelength different from at least a portion of the wavelength of the light emitted, has axial absorption anisotropy with different amounts of light absorption, and can emit polarized light in the visible light region by absorbing light; The filter is a light-corrected single-unit with a transmittance of 45 to 100% and can absorb light in the visible light region; and The above optical system satisfies the relationship of formula (1) or formula (2), A em-L-λmax ×F em-L <0.6×A fi-em-λmax <0.35 Formula (1) In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A fi-em-λmax Indicates the absorbance of the filter at the maximum emission wavelength of the polarized light emitting element; 0 <TAF em-L <0.7×TA fi-em Formula (2) Where, TA fi-em TAF is the value obtained by integrating the absorbance of each wavelength of the filter in the wavelength range where the polarized light emitting element emits light. em-L It represents the value obtained by integrating the absorbance at each wavelength on the axis where the light absorption of the polarized light emitting element is the lowest and the quantum yield on the axis where the light absorption of the polarized light emitting element is the lowest in the light absorption wavelength range of the aforementioned polarized light emitting element.

2. The optical system according to claim 1, at least satisfying the above formula (2).

3. The optical system according to claim 1 or 2, wherein: The light-corrected monomer transmittance of the aforementioned filter is 50 to 99.9%.

4. The optical system according to claim 1 or 2, wherein: The aforementioned filter is a polarizing element satisfying formula (3), A em-L-λmax ×F em-L <0.6×A Pol-Kz-em-L-λmax <0.7 Formula (3) In the formula, A em-L-λmax Indicates the absorbance at the maximum absorption wavelength of the axis where the light absorption of the polarized light emitting element is the lowest, F em-L The quantum yield of the axis where the light absorption of the polarized light emitting element is the lowest, A Pol-Kz-em-L-λmax It indicates the absorbance of the polarizing element at the highest absorption axis at the wavelength with the maximum emission along the axis where the emission amount of the polarizing element is the weakest.

5. The optical system according to claim 1 or 2, wherein: The aforementioned filter is a polarizing element satisfying formula (4), 0 <TAF em-L <0.7×TA pol-Kz-em Formula (4) Where, TA pol-Kz-em TAF is the value obtained by integrating the absorbance of each wavelength of the polarizing element at the highest absorption axis in the wavelength range in which the polarizing element emits light. em-L The expression is the same as that of formula (2).

6. The optical system according to claim 1 or 2, wherein: The optical filter is a polarizing element, and includes the polarizing element and the optical filter in such a manner that an axis where the light emission of the polarizing element is weakest and an axis where the light absorbance of the polarizing element is high are parallel.

7. The optical system according to claim 1 or 2, wherein: The hue of the aforementioned filter is -5 ＊ <+3 and b ＊ <±3.​ 8. The optical system according to claim 1 or 2, wherein: The polarized light emitting element contains a polarized light emitting dye, and the polarized light emitting dye is oriented.

9. The optical system according to claim 1 or 2, wherein: The polarized light emitting element absorbs light in the ultraviolet region to the near-ultraviolet visible region to emit polarized light.

10. The optical system according to claim 1 or 2, wherein: The polarized light emitting element has a maximum absorption wavelength of light in the ultraviolet region to the near ultraviolet visible light region.

11. The optical system according to claim 1 or 2, wherein the polarized light emitting element and the optical filter are stacked. 12 . The optical system according to claim 1 , comprising a phase difference plate.

13. The optical system according to claim 1 or 2, wherein: The aforementioned filter is located on the viewing side. 14 . A display device comprising the optical system according to claim 1 .

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