Luminescent compound or its salt, and polarized light emitting element, polarized light emitting plate and display device obtained by using the same

Abstract

The present invention is a luminescent compound represented by the following formula (1) or a salt thereof. (In formula (1), k is 0 or 1, at least one of X and Y represents a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent or a group of formula (2), and the other X and Y are selected from a nitro group, an amino group which may have a substituent, an alkyl group having 1 to 4 carbon atoms which may have a substituent or an alkoxy group having 1 to 4 carbon atoms which may have a substituent, a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, or a group of formula (2). M is a hydrogen atom, a metal ion or an ammonium ion, and m represents an integer from 0 to 2. In formula (2), ※ represents the bonding position of X and Y in formula (1), and Z is selected from a heterocyclic group of a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a distyryl group which may have a substituent, and a benzoyl group which may have a substituent. t represents an integer from 0 or 1.).

Description

Technical Field

[0001] The present invention relates to a novel luminescent compound or a salt thereof, and a polarized light emitting element, a polarized light emitting plate and a display obtained by using the compound. Background Art

[0002] Polarizing plates with penetrating / shielding functions and liquid crystals with optical switching functions are both components of displays such as liquid crystal displays (LCDs). The application areas of LCDs equipped with such polarizing plates have also expanded from small machines such as computers and clocks in the early days to notebook computers, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, and indoor and outdoor measuring machines. In addition, polarizing plates can also be applied to lenses with polarizing functions, such as sunglasses with higher visibility or polarized glasses that have been used in recent years for 3D televisions. As mentioned above, the use of polarizing plates has expanded to a wide range, and its use conditions also span the range 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 high durability are required.

[0003] Usually, the polarizing film constituting the polarizing plate is made by dyeing the film of polyvinyl alcohol or its derivatives of the polarizing film substrate or extending and aligning the film containing iodine or dichroic dyes, or can be made by dehydrochlorination of polyvinyl chloride film or dehydration of polyvinyl alcohol film to generate polyene and aligning it. The polarizing plate composed of such a traditional polarizing film has a reduced transmittance because it uses a dichroic dye with absorption in the visible light domain. For example, the transmittance of a general polarizing plate sold on the market is 35 to 45%. For the traditional polarizing plate, there is a problem of reduced transmittance in the visible light domain. As a technology that maintains a certain degree of transmittance in the visible light domain and has a polarizing function, the technology of ultraviolet polarizing plate has been recorded in patent document 1. However, since this technology also uses yellow pigments with absorption in the visible light domain, the transmittance is not enough and a strong yellow coloring is confirmed. When a polarizing plate with a low transmittance in the visible light domain is used on a display, since the transmittance of the entire display will be reduced, a method of obtaining polarization without using a traditional polarizing plate is being studied. As such a method, Patent Documents 2 to 4 describe elements that emit polarized light.

[0004] However, the polarized light emitting elements described in Patent Documents 2 to 4 are expensive due to the use of special metals, such as rare and expensive metals such as lanthanide or europium, and are very difficult to manufacture and are not suitable for mass production. In addition, these polarized light emitting elements are difficult to use in displays because the polarized light emitted is weak; in addition, linearly polarized light cannot be obtained. Therefore, it is desirable to develop a novel element and material therefor that exhibits the effect of emitting polarized light, has high transmittance (transparency) in the visible light region, and can be applied to liquid crystal displays and the like that require durability in harsh environments.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] WO2005 / 015275

[0008] [Patent Document 2] Japanese Patent Application Publication No. 2008-224854

[0009] [Patent Document 3] Japanese Patent No. 5849255

[0010] [Patent Document 4] Japanese Patent No. 5713360

[0011] [Patent Document 5] Japanese Patent Application Publication No. 2001-240762

[0012] [Patent document 6] WO2016 / 186196. Summary of the invention

[0013] [Problems that the invention aims to solve]

[0014] The purpose of the present invention is to provide a novel compound, as well as a polarized light-emitting element, a polarized light-emitting plate and a display device using the same, which can be applied to liquid crystal displays that require high transmittance in the visible light domain and high durability in harsh environments.

[0015] [Solution to the problem]

[0016] As a result of in-depth research conducted by the inventors to achieve this purpose, it was found that a polarized light-emitting element and a polarized light-emitting plate containing a compound or a salt thereof having a specific structure have a high dichroic ratio in light from the ultraviolet to near ultraviolet visible light (e.g., light from 300 to 430 nm), high transmittance in the visible light domain, and excellent durability in harsh and harsh environments. In addition, it was found that a compound or a salt thereof having such a specific structure would emit polarized light in the visible light domain by irradiation with light from the ultraviolet to near ultraviolet visible light (e.g., light from 300 to 430 nm), thereby completing the present invention.

[0017] That is, the present invention relates to each of the following aspects [1] to

[11] .

[0018] [1] A luminescent compound represented by the following formula (1) or a salt thereof.

[0019]

[0020] (In formula (1), k each independently represents an integer of 0 or 1, at least one of X and Y represents a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, or a group represented by formula (2), and the other X and Y each independently represent a group selected from the group consisting of a nitro group, an amino group which may have a substituent, an alkyl group having 1 to 4 carbon atoms which may have a substituent, an alkoxy group having 1 to 4 carbon atoms which may have a substituent, a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, or a group represented by formula (2). M represents a hydrogen atom, a metal ion, or an ammonium ion, and m each independently represents an integer of 0 to 2. In formula (2), * represents the bonding position of X and Y in formula (1), and Z is a group selected from the group consisting of a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a distyryl group which may have a substituent, a benzoyl group which may have a substituent, or a heterocyclic group which may have a substituent. t represents an integer of 0 or 1.)

[0021] [2] A luminescent compound or a salt thereof as described in item [1], wherein X and Y in the above formula (1) and at least one of X and Y in the above formula (1) when Z is represented by the above formula (2) is a group selected from the group consisting of the following formulae (3) to (7).

[0022]

[0023] (In the above formula (3) and formula (4), A is independently selected from the group consisting of a hydrogen atom, a halogen group, a nitro group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms with a sulfonic acid group, an alkyl group having 1 to 4 carbon atoms with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms with a carboxyl group, an alkoxy group having 1 to 4 carbon atoms with a sulfonic acid group, an alkoxy group having 1 to 4 carbon atoms with a hydroxyl group, and an alkoxy group having 1 to 4 carbon atoms with a carboxyl group, q 1 represents an integer from 0 to 4. M in the above formulae (3) to (7) is as defined in the above formula (1), and M in the above formulae (3) to (7) and M in the above formula (1) may be the same, and n 1 、n 2 Each independently represents an integer from 0 to 3. * in the above formulae (3) to (7) respectively represents a bonding position in X or Y in the above formula (1), or a bonding position in Z in the above formula (2).

[0024] [3] A luminescent compound or a salt thereof as described in item [1] or [2], wherein k in the above formula (1) is 0 or 1, at least one of X and Y is selected from any group consisting of formulas (2) to (7), and when at least one of X and Y is formula (2), Z is selected from any group consisting of formulas (3) to (7).

[0025] [4] A luminescent compound or a salt thereof as described in item [1] or [2], wherein each k in the above formula (1) is 0, X and Y are each a group selected from the group consisting of formulas (2) to (7), and when X and Y are formula (2), Z is selected from the group consisting of formulas (3) to (7).

[0026] [5] A luminescent compound or a salt thereof as described in item [1] or [2], wherein each k in the above formula (1) is 1, X and Y are each a group selected from the group consisting of formulas (2) to (7), and when X and Y are formula (2), Z is selected from the group consisting of formulas (3) to (7).

[0027] [6] A polarized light emitting element having a polarized light emitting function and comprising the light emitting compound or a salt thereof according to any one of [1] to [5].

[0028] [7] The polarized light-emitting element according to item [6] further contains one or more organic dyes or fluorescent dyes other than the above-mentioned light-emitting compound or its salt.

[0029] [8] The polarized light-emitting element as described in item [6] or [7] further comprises a substrate.

[0030] [9] The polarized light-emitting element according to [8], wherein the substrate comprises a film of a polyvinyl alcohol resin or a derivative thereof.

[0031]

[10] A polarized light emitting plate comprising: a polarized light emitting element according to any one of [6] to [9] provided with a transparent protective film on at least one surface thereof.

[0032]

[11] A display device comprising the polarized light emitting element according to any one of [6] to [9] or the polarized light emitting plate according to

[10] .

[0033] [Effects of the Invention]

[0034] The luminescent compound or its salt with a specific structure of the present invention absorbs light from the ultraviolet domain to the visible domain (for example, light from the ultraviolet domain to the near ultraviolet visible domain, specifically 300 to 430nm light), and uses its energy to display polarized light luminescence in the visible domain. In addition, the polarized light emitting element and polarized light emitting plate made using the luminescent compound or its salt show high polarization in the absorption wavelength. Therefore, by using this kind of formula (1) compound or its salt, even without using a highly rare lanthanide metal, it is also possible to have a high polarization in the light from the ultraviolet domain to the near ultraviolet visible domain, while providing a novel polarized light emitting element and polarized light emitting plate showing polarized light luminescence. In addition, the polarized light emitting element and polarized light emitting plate of the present invention show high transmittance in the visible light domain, and show excellent durability for heat, humidity, etc. Therefore, the polarized light emitting element and polarized light emitting plate can be applied to display devices such as liquid crystal displays that require high transmittance in the visible light domain and high durability in harsh environments. DETAILED DESCRIPTION

[0035] [Luminescent Compounds]

[0036] The light-emitting compound of the present invention is represented by the above formula (1). The light-emitting compound may be in the form of a salt. In the present specification, the light-emitting compound or its salt may be simply referred to as the light-emitting compound.

[0037] In formula (1), k each independently represents an integer of 0 or 1, at least one of X and Y represents a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, or a group represented by formula (2), and the other X and Y each independently represents a group selected from the group consisting of a nitro group, an amino group which may have a substituent, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms which may have a substituent, a heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, or a structure of formula (2). M represents a hydrogen atom, a metal ion, or an ammonium ion, and m each independently represents an integer of 0 to 2. In formula (2), * represents the bonding position of X and Y in formula (1), and Z is a group selected from the group consisting of a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a distyryl group which may have a substituent, a benzoyl group which may have a substituent, or a heterocyclic group which may have a substituent. t represents an integer of 0 or 1.

[0038] The above-mentioned heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent means, for example, a heterocyclic group having at least one of a nitrogen atom and a sulfur atom as a ring constituent, and the heterocyclic group also contains a polycyclic heterocyclic group further containing an aromatic ring such as a benzene ring or a naphthalene ring. Examples of the heterocyclic group having at least one of the nitrogen atom and the sulfur atom as a ring constituent include, for example, pyrrolyl, benzopyrrolyl, thienyl, benzothienyl, thiazolyl, benzothiazolyl, naphthiazolyl, triazolyl, benzotriazolyl, naphthiatriazolyl, thiadiazolyl, benzothiadiazolyl, pyridyl, and the like.

[0039] Examples of the amino group which may have a substituent include amino groups; monosubstituted amino groups such as methylamino, ethylamino, n-butylamino, phenylamino, and naphthylamino; and disubstituted amino groups such as dimethylamino, diethylamino, di-n-butylamino, diphenylamino, ethylmethylamino, and ethylphenylamino.

[0040] Examples of the alkyl group having 1 to 4 carbon atoms which may have a substituent include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl and cyclobutyl.

[0041] Examples of the alkoxy group having 1 to 4 carbon atoms which may have a substituent include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, and a cyclobutoxy group.

[0042] The substituents in the above-mentioned heterocyclic group containing a nitrogen atom or a sulfur atom which may have a substituent, the amino group which may have a substituent, the alkyl group having 1 to 4 carbon atoms which may have a substituent, and the alkoxy group having 1 to 4 carbon atoms which may have a substituent are not particularly limited, but examples thereof include hydroxyl, cyano, phosphoric acid, sulfonic acid, carboxyl, and amino groups.

[0043] In the above formula (1), M represents a hydrogen atom, a metal ion or an ammonium ion. Examples of metal ions include alkali metal ions such as lithium ions, sodium ions, and potassium ions, and alkaline earth metal ions such as calcium ions and magnesium ions. Examples of ammonium ions include ammonium ions, methylammonium ions, dimethylammonium ions, triethylammonium ions, tetraethylammonium ions, tetra-n-propylammonium ions, tetra-n-butylammonium ions, monoethanolammonium ions, diethanolammonium ions, triethanolammonium ions, monoisopropanolammonium ions, diisopropanolammonium ions, triisopropanolammonium ions, and triethanolammonium ions. More specifically, for example, when M is a hydrogen atom, it represents sulfonic acid (-SO3H), when M is a sodium ion, it represents sodium sulfonate (-SO3Na), and when M is an ammonium ion, it represents ammonium sulfonate (-SO3NH4). Among these, lithium ions, ammonium ions, and sodium ions are particularly preferred.

[0044] In the above formula (2), * represents the bonding position of X and Y in formula (1), and Z is selected from the group consisting of a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a distyryl group which may have a substituent, a benzoyl group which may have a substituent, or a heterocyclic group which may have a substituent. t represents an integer of 0 or 1. The substituent that Z may have is not particularly limited, and examples thereof include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an amino group, a nitro group, a sulfonic acid group, a hydroxyl group, a cyano group, a phosphoric acid group, and a carboxyl group.

[0045] The heterocyclic group which may have a substituent may be the same as the nitrogen atom or sulfur atom-containing heterocyclic group which may have a substituent in the above formula (1), and may also be a furyl group or a benzofuranyl group which may have an oxygen atom as a ring component.

[0046] When X and Y in the above formula (1) are represented by the above formula (2), and when at least one of X and Y in the above formula (1) is represented by the above formula (2), at least one Z is preferably a group selected from the group consisting of the above formulas (3) to (7).

[0047] In the above formula (3) and formula (4), A is independently selected from the group consisting of a hydrogen atom, a halogen group, a nitro group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms with a sulfonic acid group, an alkyl group having 1 to 4 carbon atoms with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms with a carboxyl group, an alkoxy group having 1 to 4 carbon atoms with a sulfonic acid group, an alkoxy group having 1 to 4 carbon atoms with a hydroxyl group, and an alkoxy group having 1 to 4 carbon atoms with a carboxyl group, and q 1 represents an integer from 0 to 4, M in the above formulae (3) to (7) is as defined in the above formula (1), and M in the above formulae (3) to (7) and M in the above formula (1) may be the same, and n 1 、n 2 Each independently represents an integer of 0 to 3. * in the above formulae (3) to (7) represents a bonding position in X or Y in the above formula (1) or a bonding position in Z in the above formula (2).

[0048] Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl and cyclobutyl.

[0049] Examples of the C1-4 alkyl group having a sulfonic acid group include a sulfonic acid methyl group, a sulfonic acid ethyl group, a sulfonic acid n-propyl group, a sulfonic acid n-butyl group, and a sulfonic acid sec-butyl group.

[0050] Examples of the halogen group include a fluoro group, a chloro group, a bromo group, and an iodo group.

[0051] Examples of the alkoxy group having 1 to 4 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, and cyclobutoxy.

[0052] Examples of the alkyl group having 1 to 4 carbon atoms and having a hydroxyl group include hydroxymethyl, hydroxyethyl, hydroxy-n-propyl, hydroxyisopropyl, hydroxy-n-butyl, hydroxy-sec-butyl, hydroxy-tert-butyl and hydroxycyclobutyl.

[0053] Examples of the C1-4 alkyl group having a carboxyl group include carboxymethyl, carboxyethyl, carboxy-n-propyl, carboxy-isopropyl, carboxy-n-butyl, carboxy-sec-butyl, carboxy-tert-butyl and carboxycyclobutyl.

[0054] Examples of the alkoxy group having 1 to 4 carbon atoms and having a sulfonic acid group include sulfonic acid methoxy, sulfonic acid ethoxy, sulfonic acid n-propoxy, sulfonic acid isopropoxy, sulfonic acid n-butoxy, sulfonic acid sec-butoxy, sulfonic acid tert-butoxy, and sulfonic acid cyclobutoxy.

[0055] Examples of the alkoxy group having 1 to 4 carbon atoms and having a hydroxy group include hydroxymethoxy, hydroxyethoxy, hydroxy-n-propoxy, hydroxyisopropoxy, hydroxy-n-butoxy, hydroxy-sec-butoxy, hydroxy-tert-butoxy and hydroxycyclobutoxy.

[0056] Examples of the alkoxy group having 1 to 4 carbon atoms and having a carboxyl group include carboxymethoxy, carboxyethoxy, carboxy-n-propoxy, carboxy-isopropoxy, carboxy-n-butoxy, carboxy-sec-butoxy, carboxy-tert-butoxy and carboxycyclobutoxy.

[0057] In one embodiment, k in the above formula (1) is 0 or 1, at least one of X and Y is selected from any group consisting of formulas (2) to (7), and when at least one of X and Y is formula (2), Z may be selected from any group consisting of formulas (3) to (7). In the above formula (1), each k is 0, and each of X and Y is selected from any group consisting of formulas (2) to (7). When X and Y are formula (2), Z is preferably selected from any group consisting of formulas (3) to (7). In the above formula (1), each k is 1, and each of X and Y is selected from any group consisting of formulas (2) to (7). When X and Y are formula (2), Z is particularly preferably selected from any group consisting of formulas (3) to (7).

[0058] A more preferred example of a method for synthesizing the compound represented by formula (1) is described below. The method for synthesizing the present compound is not limited to the following example, and for example, the compound represented by formula (1) can be obtained by the method disclosed in the above-mentioned Patent Documents 5 and 6.

[0059] For example, one equivalent of the compound represented by the following formula (10) and one equivalent of the compound represented by the following formula (11) are heated in water and dissolved by adding caustic soda. Phenyl chloroformate represented by the formula (9) which can be purchased from commercial products is added to this solution to cause ureidation reaction. The conditions of the ureidation reaction are not particularly limited, but for example, the reaction is carried out at a temperature of 30°C to 100°C (preferably 40°C to 90°C) for about 30 minutes to 15 hours (preferably about 1 hour to 10 hours). After the reaction is completed, it is cooled to room temperature, or salt is added to salt out and filtered to obtain the target product.

[0060]

[0061] (In the above formulas (9) to (11), each of X, Y, k, M, and m may be the same as in the above formula (1).)

[0062] Next, specific examples of the light-emitting compound represented by the above formula (1) are listed below: In addition, the sulfonic acid group and the like in the formula are represented in the form of a free acid.

[0063]

[0064]

[0065] The compound represented by the above formula (1) or its salt can be used as a compound capable of polarized light emission. The luminescent compound represented by formula (1) or its salt can be combined with one or more (without particular limitation) organic dyes or fluorescent dyes known in the industry other than the above luminescent compound or its salt, and a known method is used to make it contained in a substrate such as a polymer film such as polyvinyl alcohol or its derivatives and oriented, and a polarized light emitting element is manufactured. The obtained polarized light emitting element is formed as a polarized light emitting plate with an additional transparent protective film, and a hard coating or AR (anti-reflection) layer and a support body are optionally further provided on the polarized light emitting plate, and can be applied to liquid crystal projectors, computers, clocks, notebook computers, word processors, liquid crystal televisions, car navigation devices, security displays, anti-counterfeiting and indoor and outdoor measuring instruments and displays, etc., lenses or glasses. In addition, in this specification, there is a situation where the organic dyes or fluorescent dyes known in the industry other than the luminescent compound or its salt are simply referred to as other organic dyes.

[0066] [Polarized light emitting element]

[0067] A polarized light emitting device containing the light emitting compound represented by the above formula (1) or a salt thereof is also included in the present invention.

[0068] The polarized light emitting element preferably contains a luminescent compound represented by the above formula (1) or a salt thereof and a substrate on which the luminescent compound or a salt thereof is adsorbed and aligned. The polarized light emitting element may contain one or more luminescent compounds represented by the above formula (1) or a salt thereof.

[0069] The above-mentioned substrate is preferably a film obtained by making a hydrophilic polymer that can adsorb a luminescent compound or its salt. Although there is no particular limitation on the hydrophilic polymer, examples thereof include polyvinyl alcohol resins, amylose resins, starch resins, cellulose resins, and polyacrylate resins. From the viewpoints of the adsorption, processability, and orientation of the luminescent compound or the salt, polyvinyl alcohol resins or derivatives thereof are preferred among such resins. Polyvinyl alcohol resins or derivatives thereof may also be modified with olefins such as ethylene and propylene, or unsaturated carboxylic acids such as crotonic acid, acrylic acid, methacrylic acid, and maleic acid. The shape of the substrate is not particularly limited, and it can be made into any shape such as a film, sheet, flat plate, curved plate, and hemispherical. In addition, the thickness of the substrate (before swelling treatment) is usually 10 μm to 100 μm, preferably 20 μm to 80 μm.

[0070] The content of the luminescent compound or its salt represented by the above formula (1) in the above polarized light-emitting element is not particularly limited and can be designed with any transmittance. Its content can be arbitrarily set in accordance with the transmittance required by the polarized light-emitting element. The polarization performance of the polarized light-emitting element depends not only on the content of the luminescent compound or its salt represented by the formula (1) in the polarized light-emitting element, but also on various factors such as the swelling property of the substrate adsorbing the luminescent compound, the elongation ratio, the dyeing time, the dyeing temperature, the pH during dyeing, the influence of salt, etc. Therefore, the content of the luminescent compound or its salt represented by the formula (1) in the polarized light-emitting element can be determined in accordance with the swelling degree of the substrate, the temperature, time, pH, type of salt, concentration of salt, and elongation ratio during dyeing. Such content adjustment can be carried out as appropriate.

[0071] The above-mentioned polarized light emitting element may optionally further contain one or more other organic dyes within the range that does not hinder the polarization performance or for the purpose of color adjustment. Although there is no particular limitation on the other organic dyes that can be used in combination, dyes with high dichroism are preferred, and dyes that do not affect the polarization performance of light in the ultraviolet light region to the near-ultraviolet visible light region of the luminescent compound of formula (1) are preferred. Other organic dyes that can be used together include, for example, CIDirect.Yellow12, CIDirect.Yellow 28, CIDirect.Yellow 44, CIDirect.Orange 26, CIDirect.Orange 39, CIDirect.Orange 71, CIDirect.Orange 107, CIDirect.Red 2, CIDirect.Red 31, CIDirect.Red 79, CIDirect.Red 81, CIDirect.Red 247, CIDirect.Blue 69, CIDirect.Blue78, CIDirect.Green 80 and CIDirect.Green 59. These other organic dyes may be in the form of free acids, alkali metal salts (such as Na salts, K salts, and Li salts), ammonium salts, or amine salts.

[0072] When the above other organic dyes are used in combination, the types of other organic dyes to be used can be selected according to the purpose of adjusting the color of the polarized light-emitting element to be manufactured. In addition, although the content of other organic dyes is not particularly limited, it is usually preferred that the total amount of other organic dyes used in combination is in the range of 1 to 1,000 parts by mass relative to 100 parts by mass of the luminescent compound of formula (1) or its salt.

[0073] <Method for manufacturing polarized light emitting element>

[0074] Next, the method for manufacturing the polarized light-emitting element of the present invention is described. The manufacturing method is not limited, and includes the following steps: for example, a step of preparing a substrate, a swelling step of extending the substrate by swelling by immersing the substrate in a swelling solution, a dyeing step of immersing the swollen substrate in a dyeing solution containing at least one luminescent compound represented by the above formula (1), and adsorbing the luminescent compound represented by the formula (1) as a luminescent compound or a salt thereof in the substrate, a crosslinking step of immersing the substrate adsorbed with the luminescent compound represented by the formula (1) or a salt thereof in a solution containing boric acid and crosslinking the luminescent compound represented by the formula (1) or a salt thereof in the substrate, an extending step of extending the substrate crosslinked with the luminescent compound or a salt thereof in a certain direction so that the luminescent compound represented by the formula (1) or a salt thereof is arranged in a certain direction, a washing step of washing the extended substrate with a washing solution, and a drying step of drying the washed substrate.

[0075] (Preparation of substrate)

[0076] Prepare a substrate for adsorbing / aligning the luminescent compound represented by the above formula (1). The substrate can be, for example, a film composed of a commercially available polyvinyl alcohol resin or a derivative thereof, or can be made by forming a film of the polyvinyl alcohol resin. The film-forming method of the polyvinyl alcohol resin is not particularly limited, and known film-forming methods such as melt extrusion of aqueous polyvinyl alcohol, cast film-forming method, wet film-forming method, gel film-forming method (after briefly cooling the polyvinyl alcohol aqueous solution to gel, the solvent is extracted and removed), cast film-forming method (casting the polyvinyl alcohol aqueous solution on a substrate and drying it), and a combination of these methods can be used. Although the degree of polymerization of polyethylene can be 1,000 to 10,000, 1,500 to 6,000 is preferred, and 2,000 to 6,000 is more preferred.

[0077] (Swelling step)

[0078] Next, the substrate is subjected to a swelling treatment. The swelling treatment is preferably performed by immersing the substrate in a swelling liquid at 20 to 50° C. for 30 seconds to 10 minutes. The swelling liquid is preferably water. The stretching ratio of the substrate by the swelling liquid is preferably adjusted to 1.00 to 1.50 times, and more preferably adjusted to 1.10 to 1.35 times.

[0079] (Dyeing Steps)

[0080] Next, at least one luminescent compound of formula (1) or a salt thereof is adsorbed and impregnated on the substrate subjected to the swelling treatment as described above. The dyeing step is not particularly limited as long as the luminescent compound or a salt thereof is adsorbed and impregnated on the substrate, but it is preferred to immerse the substrate in a dyeing solution (generally an aqueous solution) containing the luminescent compound or a salt thereof. Alternatively, the luminescent compound or a salt thereof may be adsorbed by applying the dyeing solution on the substrate. The concentration of the luminescent compound or a salt thereof in the dyeing solution is not particularly limited as long as the luminescent compound or a salt thereof is sufficiently adsorbed on the substrate, but it is preferably, for example, 0.001 to 3% by mass in the dyeing solution, and more preferably 0.001 to 1.0% by mass.

[0081] 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 for immersing the substrate in the dyeing solution can be appropriately adjusted, preferably between 30 seconds and 20 minutes, and more preferably between 1 to 10 minutes.

[0082] As the luminescent compound or its salt represented by the above formula (1) as the compound contained in the above dyeing solution, one kind can be used alone or two or more kinds can be used in combination. Since the luminescent compound or its salt represented by the above formula (1) has different luminescent colors due to different structures, the luminescent color produced can be appropriately adjusted to the desired color by containing two or more luminescent compounds or their salts in the substrate. In addition, the dyeing solution may optionally further contain one or more of the above other organic dyes. In the manufacture of the polarized light-emitting element and the polarized light-emitting plate described in this specification, the luminescent compound (or its salt) represented by formula (1) and other organic dyes are sometimes collectively referred to as "polarizing pigments".

[0083] In addition to the above-mentioned polarizing pigment, the above-mentioned dyeing solution may also contain dyeing auxiliary agents. Examples of dyeing auxiliary agents include sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulfate (glauber's salt), anhydrous sodium sulfate and sodium tripolyphosphate, with sulfuric acid being preferred. The content of the dyeing auxiliary agent can be arbitrarily adjusted according to the dyeability of the polarizing pigment used, by the above-mentioned immersion time and the temperature of the dyeing solution. The content of the dyeing auxiliary agent (when used) is preferably 0.05 to 10% by mass in the dyeing solution, and more preferably 0.05 to 2% by mass.

[0084] After the dyeing step, a preliminary washing step can be arbitrarily performed to remove the residual dyeing solution attached to the surface of the substrate in the dyeing step. By performing the preliminary washing step, the luminescent compound or its salt remaining on the surface of the substrate can be inhibited from transferring to the post-treatment liquid. Water is usually used as the washing liquid in the preliminary washing step. The washing method is preferably to immerse the dyed substrate in the washing liquid. On the other hand, the washing liquid can also be applied to the substrate for washing. Although there is no particular restriction on the washing time, 1 to 300 seconds is preferred, and 1 to 60 seconds is more preferred. The temperature of the washing liquid in the preliminary washing step must not dissolve the material constituting the substrate, and can usually be 5 to 40°C. In addition, since even if there is no preliminary washing step, it will not cause a particularly large impact on the performance of the polarized light-emitting element, the preliminary washing step can also be omitted.

[0085] (Cross-linking step)

[0086] After the dyeing step or the preliminary cleaning 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 on the substrate. The crosslinking agent in the treatment solution is preferably a solution containing boric acid. Although the solvent in the treatment solution is not particularly limited, water is preferred. The boric acid concentration in the treatment solution is preferably 0.1 to 15% by mass, and 0.1 to 10% by mass is more preferred. The temperature of the treatment solution is preferably 30 to 80°C, and 40 to 75°C is more preferred. In addition, the treatment time of this crosslinking step is preferably 30 seconds to 10 minutes, and 1 to 6 minutes is more preferred. The method for manufacturing a polarized light-emitting element of the present invention has this crosslinking step, so that the resulting polarized light-emitting element emits polarized light with high brightness and high polarization. This is an excellent effect that is completely unexpected by the function of boric acid used in the prior art for the purpose of improving water resistance or light transmittance. In addition, the crosslinking step can be carried out by further combining a repair step with an aqueous solution containing a cationic polymer compound. Polarized dyes can be fixed by the repairing step. In this case, cationic polymer compounds can be used, for example, dicyanamide and formalin polycondensates as dicyano groups, dicyandiamide / diethylenetriamine polycondensates as polyamine groups, epichlorohydrin / dimethylamine-added polymers as polycations, dimethyldiallylammonium chloride / dioxide ion copolymers, diallylamine salt polymers, dimethyldiallylammonium chloride polymers, allylamine salt polymers, and dialkylaminoethyl acrylate quaternary salt polymers.

[0087] (Extended Steps)

[0088] The stretching step is performed after or at the same time as the crosslinking step. The stretching step is performed by stretching the substrate in one direction. The stretching method can be either a wet stretching method or a dry stretching method. The stretching ratio is preferably 3 times or more, and 5 to 9 times is more preferred.

[0089] In the dry stretching method, when the stretching heating medium is an air medium, it is preferred to stretch the substrate at a temperature of the air medium between room temperature and 180°C. In addition, the humidity is preferably in an environment of 20 to 95% RH. Although the substrate heating method can be listed as: for example, a roller belt stretching method, a roller heating stretching method, a hot inter-pressure stretching method, and an infrared heating stretching method, it is not limited to these stretching methods. The dry stretching step can be implemented in a single stage of stretching, or in a multi-stage stretching step of more than two stages.

[0090] In the wet stretching method, it is preferred to stretch the substrate in water, a water-soluble organic solvent or a mixed solution thereof. It is more preferred to carry out the stretching treatment while immersing the substrate in a solution containing at least one cross-linking agent (that is, the cross-linking step and the stretching step may also be carried out simultaneously). The cross-linking agent may be, for example, boric acid in the cross-linking agent step described above, and it is more preferred to carry out the stretching treatment 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 preferably 2 to 7 minutes. The wet stretching step may be carried out in a single stage of stretching, or in a multi-stage stretching of more than two stages. In addition, the stretching treatment may be carried out arbitrarily before the dyeing step, and at this time, the orientation of the luminescent compound of formula (1) or its salt may also be carried out simultaneously at the timing of dyeing.

[0091] (Washing Steps)

[0092] After the extension step is implemented, since there will be precipitation of cross-linking agent or foreign matter attached to the surface of the substrate, a washing step of washing the surface of the substrate can 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 liquid can also be applied or coated on the substrate. Water is preferably the washing liquid. The washing treatment can be implemented in one stage, or in multiple stages of more than two stages. Although there is no particular limitation on the temperature of the washing solution in the washing step, it is usually 5 to 50°C, preferably 10 to 40°C, and can also be room temperature.

[0093] The solvent of the solution or treatment liquid used in each of the above steps may include, in addition to water, alcohols such as dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropanol, glycerol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol or trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. The solvent of the solution or treatment liquid is not limited to these, but water is most preferred. In addition, one of these solvents of the solution or treatment liquid may be used alone, or a mixture of two or more thereof may be used.

[0094] (Drying Step)

[0095] After the washing step, a drying step of the substrate is performed. The drying process can be performed by natural drying, but in order to further improve the drying efficiency, it can also be performed by compression using a roller or surface moisture removal using an air knife or a water suction roller. In addition, air drying can also be performed. The temperature of the drying process 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.

[0096] The above-mentioned method can be used as an example to prepare the polarized light emitting element of the present invention. In addition, the luminescent compound represented by formula (1) or its salt in the present invention can be mixed with liquid crystal and aligned on a substrate, or these can be aligned by a coating method distributed on a substrate, thereby manufacturing polarized light emitting elements with various colors or neutral gray.

[0097] [Polarized light panel]

[0098] A polarized light emitting plate including the above-mentioned polarized light emitting element is also included in the present invention.

[0099] The polarized light emitting plate of the present invention preferably has a transparent protective film on at least one side of the polarized light emitting element. The transparent protective film is used to improve the water resistance or handleability of the polarized light emitting element. Therefore, it is preferred that the transparent protective film does not have any effect on the polarization effect displayed by the polarized light emitting element of the present invention.

[0100] 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 shape of the polarized light-emitting element. In addition to transparency and mechanical strength, the transparent protective film is preferably a plastic film with excellent thermal stability, moisture shielding, etc. The materials forming this transparent protective film can be listed as: for example, cellulose acetate film, acrylic film, fluorine film such as tetrafluoroethylene / hexafluoropropylene copolymer, or film composed of polyester resin, polyolefin resin or polyamide resin. 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 40μm to 100μm. Although there is no particular limitation on the method for manufacturing the polarized light-emitting plate of the present invention, for example, a transparent protective film can be overlapped on the polarized light-emitting element and laminated by a known formula to make a polarized light-emitting plate.

[0101] The polarized light emitting plate may also have a bonding agent layer between the transparent protective film and the polarized light emitting element for bonding the transparent protective film to the polarized light emitting element. There is no particular limitation on the bonding agent constituting the bonding agent layer, and polyvinyl alcohol bonding agents, urethane emulsion bonding agents, acrylic bonding agents, polyester-isocyanate bonding agents, etc. may be used. It is preferred to use polyvinyl alcohol bonding agents. After bonding the transparent protective film and the polarized light emitting element with the bonding agent, the polarized light emitting plate may be manufactured by drying or heat treating at an appropriate temperature.

[0102] In addition, the polarized light emitting plate may be provided with various known functional layers such as an anti-reflection layer, an anti-glare layer, and other protective films on the exposed surface of the transparent protective film. When making such layers with various functions, it is preferred to apply the materials with various functions on the exposed surface of the transparent protective film. On the other hand, the layer or film with such functions may be attached to the exposed surface of the transparent protective film by an adhesive.

[0103] The above-mentioned other transparent protective films include hard coatings such as acrylic, urethane, and polysiloxane. In addition, in order to further improve the monomer transmittance, an anti-reflection layer may be provided on the exposed surface of the transparent protective film. The anti-reflection layer may be formed by, for example, evaporating or sputtering silicon dioxide, titanium oxide, and the like on the transparent protective film, or coating a thin fluorine-based material on the transparent protective film.

[0104] The polarized light emitting plate may be further provided with a transparent support such as glass, crystal, sapphire, etc. There is no particular limitation on such a support, but it is preferred to have a planar portion for attaching the polarized light emitting plate. In addition, from the viewpoint of optical use, the support is preferably a transparent support. The transparent support may be an inorganic support and an organic support. For example, the support composed of inorganic materials may include supports composed of materials such as sodium glass, borosilicate glass, crystal, sapphire, spinel, etc. The organic support may include supports composed of acrylic acid, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymers, etc. There is no particular limitation on the thickness and size of the transparent support, which may be appropriately determined. In addition, in the polarized light emitting plate having such a transparent support, in order to further improve the monomer transmittance, it is preferred to provide an anti-reflection layer on one or both sides of the support surface or the polarized light emitting plate surface. In order to bond the polarized light emitting plate to the support, a transparent bonding agent is applied to the support, and then the polarized light emitting plate of the present invention is attached to the coated surface. There is no particular limitation on the bonding agent or adhesive used, and commercially available bonding agents or adhesives can be used, and acrylic bonding agents or adhesives are preferred.

[0105] In addition, the above-mentioned polarized light emitting plate can also be used as a circularly polarized light emitting plate or an elliptically polarized light emitting plate with a phase difference plate attached. At this time, when the polarized light emitting plate is further provided with a support, the support may also be a phase difference plate. Although the phase difference plate can generally be exemplified as having a phase difference value of 1 / 4λ or a phase difference value of 1 / 2λ for the absorption wavelength or luminous wavelength of light, it is not limited to these. By having a phase difference value of 1 / 4λ, the function of a circular polarizer or a circularly polarized light emitting plate can be exerted at the wavelength. By using 1 / 2λ, the purpose of converting polarized light in the direction of 90° can be achieved. In this way, a variety of functional layers, supports, etc. can be further provided on the polarized light emitting plate. Such a polarized light emitting plate can be used in various products such as liquid crystal projectors, computers, clocks, laptops, word processors, LCD TVs, car navigation systems, and indoor and outdoor measuring instruments or displays, lenses or glasses.

[0106] The polarized light emitting element and polarized light emitting plate of the present invention show high polarization in the ultraviolet to near ultraviolet visible light domain (e.g., 300 to 430nm), and show polarized light emitting effect and high transmittance in the visible light domain. In addition, since the polarized light emitting element and polarized light emitting plate of the present invention show excellent durability for heat, humidity, light, etc., their performance can be maintained even in harsh environments, and they have higher durability than traditional iodine-based polarizers. Therefore, the polarized light emitting element and polarized light emitting plate of the present invention can be applied to liquid crystal displays that require high transparency in the visible light domain and high durability in harsh environments, such as televisions, wearable devices, tablet devices, smart phones, vehicle-mounted monitors, outdoor or indoor digital signage, smart windows and other displays.

[0107] [Display device]

[0108] A display including the above-mentioned polarized light emitting element or polarized light emitting plate is also included in the present invention.

[0109] The above-mentioned display shows the polarized light luminescence effect by irradiating light from the ultraviolet range to the visible light range (for example, light from the ultraviolet range to the near-ultraviolet visible light range, specifically light from 300 to 430 nm), and uses this effect to achieve display. Because the display of the present invention has a high transmittance in the visible light range, it does not have a decrease in transmittance in the visible light range like the traditional polarizing plate, and even if the transmittance is reduced, the decrease in transmittance is significantly less than the transmittance of the traditional polarizer. For example, the iodine polarizing plate of the traditional polarizing plate or the dye-based polarizing plate using other dye compounds, when the polarization degree is set to almost 100%, the luminescence factor in the visible light range is corrected to about 35 to 43%. The reason is that although the traditional polarizing plate has both the longitudinal axis and the transverse axis as the absorption axis of light, in order to obtain a polarization degree of almost 100%, the incident light of one of the longitudinal axis or the transverse axis is absorbed, that is, polarization is generated by absorbing light in one of the axes and passing light in the other axis. In this case, since the light of one axis is absorbed and not transmitted, the transmittance is necessarily less than 50%. In addition, conventional polarizing plates are made to align the dichroic pigment in the extended film. However, the dichroic pigment is not necessarily 100% aligned. In addition, since there is a slight absorption component relative to the transmission axis of the light, if the transmittance caused by the surface reflection of the material is not less than about 43%, it is impossible to achieve almost 100% polarization. In other words, if the transmittance is not reduced, it is impossible to achieve a high polarization. On the contrary, the polarized light emitting element and polarized light emitting plate of the present invention have an axis (its polarizing function) that absorbs light in the ultraviolet light domain to the near ultraviolet visible light domain (e.g., 300 to 430nm), that is, it has a light absorption effect in the ultraviolet light domain to the near ultraviolet visible light domain (e.g., 300 to 430nm), showing a polarized light emitting effect of emitting polarized light in the visible light domain, and on the other hand, it hardly absorbs light in the visible light domain, so the transmittance of the visible light domain becomes very high. In addition, since polarized light is displayed in the visible light domain, there is no light loss compared to the use of traditional polarizers, that is, the reduction in transmittance like traditional polarizers is very small. Therefore, the display using the polarized light emitting element and polarized light emitting plate of the present invention, such as a liquid crystal display, can obtain a higher brightness than the liquid crystal display using a traditional polarizer. In addition, since the transparency of the display using the polarized light emitting element and polarized light emitting plate of the present invention is high, in the case of a liquid crystal display, an almost transparent display can also be obtained. In addition, when displaying text and images, since it can be designed to allow polarized light to pass through, even a transparent liquid crystal display can be obtained, that is, a display that can display text, etc. on a transparent display. Moreover, the display of the present invention can obtain a transparent liquid crystal display without light loss, and in particular, a see-through display.

[0110] In addition, since the above-mentioned display can also generate polarized light for light in the ultraviolet to near ultraviolet visible light range (e.g., 300 to 430 nm) that is invisible or difficult to see with the naked eye, it can be applied to a liquid crystal display that can display light in the ultraviolet to near ultraviolet visible light range. For example, by using a computer or the like to identify an image displayed in the ultraviolet to near ultraviolet visible light range, a simple and highly secure liquid crystal display that can be identified only when irradiated with light in the ultraviolet to near ultraviolet visible light range (e.g., 300 to 430 nm) can be produced.

[0111] In addition, the above-mentioned display shows polarized light emission by irradiating light in the ultraviolet range to the near ultraviolet visible range (for example, 300 to 430nm). Since a liquid crystal display using the polarized light emission can be produced, a liquid crystal display using light in the ultraviolet range to the near ultraviolet range can be realized, rather than a general liquid crystal display using visible light. That is, even in a dark space without light, as long as a space in which light in the ultraviolet range to the near ultraviolet range can be irradiated, a light-emitting liquid crystal display that can display text, images, etc. can be produced.

[0112] In addition, since the visible light domain and the ultraviolet light are different light domains, it is also possible to produce a display that combines two different displays, including a liquid crystal display unit that displays the visible light domain with light in the visible light domain and a liquid crystal display unit that displays light with the polarized light emission effect of ultraviolet light. Although there are displays that can achieve two different displays, there is no display that can achieve different displays in the ultraviolet light domain and the visible light domain through different light sources in the case of the same liquid crystal panel. Therefore, the display of the present invention can produce a novel display because it has the above-mentioned polarized light emitting element and polarized light emitting plate.

[0113] A liquid crystal display using the above-mentioned polarized light emitting element, polarized light emitting plate or display is also included in the present invention. The liquid crystal cell used in the liquid crystal display is not limited to, for example, a TN liquid crystal cell, an STN liquid crystal cell, a VA liquid crystal cell, an IPS liquid crystal cell, etc. The above-mentioned polarized light emitting element and polarized light emitting plate can use any liquid crystal display mode. Since the liquid crystal display has high durability, a liquid crystal display for vehicle use or outdoor display can be provided.

[0114] The neutral gray polarized light-emitting plate for vehicle-mounted or outdoor display using the above-mentioned polarized light-emitting element or a display containing the same is also included in the present invention. The neutral gray polarized light-emitting plate for vehicle-mounted or outdoor display has excellent polarized light-emitting performance, and does not cause discoloration or reduction in polarization performance even in high temperature and high humidity conditions inside the vehicle or outdoors. In addition, neutral gray refers to the transmittance of each wavelength in the vertical position of the visible light domain of the polarized light-emitting plate, which is significantly low or has a certain transmittance. Specifically, the vertical transmittance is less than 0.3%, preferably less than 0.1%, more preferably less than 0.03%, and particularly preferably less than 0.01%; a certain transmittance refers to the average transmittance for each wavelength, and the difference in transmittance is within 1%.

[0115] (Example)

[0116] Although the present invention is described in more detail below by way of examples, these are given as examples and the present invention is not limited thereto. In addition, unless otherwise specified, the "%" and "part" described below represent mass references. In addition, in each structural formula of the compound used in each embodiment and comparative example, the acidic functional groups such as sulfonic acid group are recorded in the form of free acid.

[0117] [Example 1]

[0118] (Synthesis example 1)

[0119] 84 parts of the compound of formula (28) were added to 800 parts of water, dissolved with sodium hydroxide, and 15.6 parts of phenyl chloroformate were added, and stirred at 50 to 70° C. for 6 hours to form ureido groups. Salting out was performed with sodium chloride, and the mixture was filtered and dried at 70° C. to obtain 56.6 parts of a ureido compound represented by formula (24) which is an example of the compound of the present invention.

[0120]

[0121] (Manufacturing of polarized light emitting elements and polarized light emitting plates)

[0122] A polyvinyl alcohol film (VF-PS#7500 manufactured by Kuraray Co., Ltd.) with a thickness of 75 μm was immersed in water at 40°C for 3 minutes to swell the film. The swollen film was immersed in a 45°C aqueous solution containing 0.2 parts by mass of the compound of the present invention of the above formula (24) obtained in Synthesis Example 1, 1.0 parts by mass of Glauber's salt and 1,000 parts by mass of water for 4 minutes to allow the film to contain the compound of formula (24). The film containing the compound of formula (24) was stretched to 5 times in a 3% boric acid aqueous solution at 50°C for 5 minutes. The stretched film was washed with water at room temperature for 20 seconds while being maintained in a stretched state, and dried at 70°C for 9 minutes to obtain a polarized light-emitting element. On both sides of the obtained polarized light-emitting element, a triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) not containing an ultraviolet absorber was laminated according to a known recipe to obtain a polarized light-emitting plate. Furthermore, even when triacetyl cellulose films are laminated on both surfaces of the polarized light emitting element, the optical characteristics of the polarized light emitting element are not affected.

[0123] [Example 2]

[0124] (Synthesis example 2)

[0125] 136 parts of the compound of formula (29) were added to 1,000 parts of water, dissolved with sodium hydroxide, and 15.6 parts of phenyl chloroformate were added, and stirred at 50 to 70°C for 6 hours to form ureido groups. Salting out was performed with sodium chloride, and the mixture was filtered and dried at 70°C to obtain 92.3 parts of the ureido compound represented by formula (12) of the example of the compound of the present invention. The polarized light-emitting element and polarized light-emitting plate of Example 1 were obtained by performing the same operation except that the compound represented by formula (12) was used instead of formula (24) in the polarized light-emitting element and polarized light-emitting plate.

[0126]

[0127] [Example 3]

[0128] (Synthesis example 3)

[0129] 61.6 parts of the compound of formula (30) were added to 600 parts of water, dissolved with sodium hydroxide, and 15.6 parts of phenyl chloroformate were added, and stirred at 50 to 70°C for 6 hours to ureidate. Salting out was performed with sodium chloride, and the mixture was filtered and dried at 70°C to obtain 48.4 parts of the ureido compound represented by formula (23) of the example of the compound of the present invention. The polarized light-emitting element and polarized light-emitting plate of Example 1 were obtained by performing the same operation except that the compound represented by formula (23) was used instead of formula (24).

[0130]

[0131] [Example 4]

[0132] (Synthesis Example 4)

[0133] 21.8 parts of the compound of formula (31) and 37.0 parts of the compound of formula (32) are added to 500 parts of water, dissolved with sodium hydroxide, and 20.0 parts of terephthaloyl chloride are slowly added over about 1 hour. After complete addition, stir at 60°C for 1 hour. After the reaction is completed, it is cooled to room temperature, filtered and dried at 70°C to obtain 10.3 parts of the compound represented by formula (33). 50.3 parts of the compound of formula (33) are added to 600 parts of water, dissolved with sodium hydroxide, and 7.8 parts of phenyl chloroformate are added, and stirred at 50 to 70°C for 6 hours to ureidate it. Salting out with sodium chloride, filtering and drying at 70, 5.8 parts of the ureido compound represented by formula (16) are obtained. The polarized light-emitting element and polarized light-emitting plate of Example 1 are obtained by the same operation except that the compound represented by formula (16) is used instead of formula (24).

[0134]

[0135] [Example 5]

[0136] (Synthesis Example 5)

[0137] 40.0 parts of the compound of formula (34) are added to 500 parts of water, dissolved with sodium hydroxide, and then 15.6 parts of phenyl chloroformate are slowly added over about 1 hour, followed by stirring at 50 to 70°C for 6 hours to react, and then 37.0 parts of the compound of formula (32) are added to react. Then, 14.2 parts of the compound described in formula (35) are added to dissolve it, and 14.1 parts of terephthaloyl chloride are slowly added over about 1 hour. After complete addition, stir at 60°C for 1 hour. After the reaction is completed, it is cooled to room temperature and filtered, and dried at 70°C to obtain 54.2 parts of the compound represented by formula (36) of the example of the compound of the present invention. The polarized light-emitting element and polarized light-emitting plate of Example 1 are obtained by performing the same operation except that the compound represented by formula (36) is used instead of formula (24) in the polarized light-emitting element and polarized light-emitting plate.

[0138]

[0139] [Example 6]

[0140] (Synthesis Example 6)

[0141] 71.2 parts of the compound of formula (37) were added to 600 parts of water, and dissolved while adding sodium hydroxide. After 15.6 parts of phenyl chloroformate were slowly added over about 1 hour, the mixture was stirred at 50 to 70°C for 6 hours to form ureido groups. Salting out was performed with sodium chloride, and the mixture was filtered and dried at 70°C to obtain 50.2 parts of the ureido compound represented by formula (21) of the example of the compound of the present invention. The polarized light-emitting element and polarized light-emitting plate of Example 1 were obtained by performing the same operation except that the compound represented by formula (21) was used instead of formula (24).

[0142]

[0143] [Comparative Example 1]

[0144] The same operation was performed to obtain a polarized light-emitting element and a polarized light-emitting plate in Example 1, except that the compound represented by formula (38) described in Japanese Patent Publication No. 4-226162 was used instead of formula (24). This polarized light-emitting plate was used as a sample for Comparative Example 1.

[0145]

[0146] [Comparative Example 2]

[0147] The same operation was performed to obtain a polarized light emitting element and a polarized light emitting plate as in Example 1 except that CIDirect Yellow 4 of the compound represented by formula (39) was used instead of formula (24). The polarized light emitting plate was used as a sample for Comparative Example 2.

[0148]

[0149] [Comparative Example 3]

[0150] The same operation is performed to obtain a polarized light-emitting element and a polarized light-emitting plate in Example 1, except that the compound represented by formula (40) is used instead of formula (24). This polarized light-emitting plate is used as a sample for Comparative Example 3.

[0151]

[0152] [assessment]

[0153] The polarized light emitting plates obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were used as measurement samples and evaluated as follows.

[0154] (a) Single-body transmittance Ts, parallel position transmittance Tp and perpendicular position transmittance Tc

[0155] The single transmittance Ts (%), parallel transmittance Tp (%) and perpendicular transmittance Tc (%) of each measurement sample were measured using a spectrophotometer ("U-4100" manufactured by Hitachi, Ltd.). Here, the single transmittance Ts (%) is the transmittance at each wavelength when measuring one measurement sample. The parallel transmittance Tp (%) is the spectral transmittance at each wavelength measured by overlapping two measurement samples so that their absorption axis directions are parallel. The perpendicular transmittance Tc (%) is the spectral transmittance at each wavelength measured by overlapping two measurement samples so that their absorption axis directions are perpendicular. The measurement of each transmittance is performed in the wavelength range of 220 to 780 nm.

[0156] (b) Polarization degree ρ

[0157] The parallel transmittance Tp and the perpendicular transmittance Tc were substituted into the following formula (I) to determine the polarization degree ρ (%) of each measurement sample.

[0158] ρ={(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100…Formula (I)

[0159] (c) Single-unit transmittance Ys after correcting the luminescence factor

[0160] The single transmittance Ys (%) of each measured sample is the transmittance after correcting the luminescence factor according to JIS Z 8722: 2009 for the single transmittance Ts obtained at a predetermined wavelength interval dλ (here 5nm) in the wavelength range of 400 to 700nm in the visible light range. Specifically, the single transmittance Ts is substituted into the formula (II) and calculated. In the following formula (II), Pλ represents the spectral distribution of the standard light (C light source), and yλ represents the 2-degree viewing angle isochromatic function.

[0161] [Number 1]

[0162]

[0163] (d) Measurement of emitted polarized light

[0164] A 375nm hand-held black light (PW-UV943H-04 manufactured by Nichia Chemical Co., Ltd.) which is an ultraviolet LED was used as a light source, and a filter (IUV-340 manufactured by Isuzu Seiko Glass Co., Ltd.) which transmits ultraviolet light and blocks visible light was set on the light source to block visible light. A polarizing plate (SKN-18043P manufactured by Pola Techno, thickness 180μm, Ys43%) having polarization in the visible and ultraviolet regions and the measurement samples obtained in each example and comparative example were set above it, and the polarized light emitted by the measurement sample was measured using a spectroradiometer (USR-40 manufactured by Ushio Electric Co., Ltd.). That is, the light from the light source was arranged so as to pass through the filter that transmits ultraviolet light and blocks visible light, the polarizing plate that has polarization in the visible and ultraviolet regions, and the measurement sample in sequence, and enter the spectroradiometer to measure the polarized light. At this time, the absorption axis when the ultraviolet absorption of the measurement sample is the maximum is overlapped in parallel with the absorption axis direction of the polarizing plate ("SKN-18043P" manufactured by Pola Techno) with polarization in the visible light region and the ultraviolet region, and the spectral luminescence amount of each wavelength is measured as Lw (weak luminescence axis), and the absorption axis when the ultraviolet absorption of the measurement sample is the maximum is overlapped in perpendicular to the polarizing plate ("SKN-18043P" manufactured by Pola Techno) with polarization in the visible light region and the ultraviolet region, and the spectral luminescence amount of each wavelength is measured as Ls (strong luminescence axis), and Lw and Ls are measured. When the absorption axis between the measurement sample and the general polarizing plate is parallel, the energy of the light emitted in the visible light region when it is perpendicular is confirmed, and the polarized luminescence light in the visible light region of 400nm to 700nm is evaluated.

[0165] (e) Light resistance test

[0166] The light resistance test was conducted by using SX-75 manufactured by Suga Test Co., Ltd., and performing light irradiation for 500 hours at an irradiation illuminance of 60 W, an ambient temperature of 30° C., and a relative humidity of 30% RH. The changes in Ls and Lw at each wavelength at this time were confirmed.

[0167] Table 1 shows the wavelength of maximum polarization of the measured samples obtained in Examples 1 to 6 and Comparative Examples 1 to 3, the single transmittance (Ts, %), parallel transmittance (Tp, %), perpendicular transmittance (Tc, %) and polarization degree (ρ, %) at the wavelength showing maximum polarization, the single transmittance after correction of the luminescence factor (Ys, %), and the polarization degree (ρy, %) after correction of the luminescence factor.

[0168] [Table 1]

[0169]

[0170] Table 2 shows Ls and Lw at each wavelength in Examples 1 to 6 and Comparative Examples 1 to 3.

[0171] [Table 2]

[0172]

[0173] Table 3 shows Ls and Lw at each wavelength after the light resistance test in Examples 1 to 4 and Comparative Example 1.

[0174] [Table 3]

[0175]

[0176] As shown in Table 1, it can be seen that the test samples of Examples 1 to 6 and Comparative Example 1 have absorption in the ultraviolet light domain and function as a polarizer in this band. On the other hand, it can be seen that the transmittance in the visible light domain (luminescence factor corrected transmittance Ys) shows more than 90%, and even if it has a polarization function in the ultraviolet light domain, the visible light transparency is high. In contrast, since Comparative Examples 2 and 3 show a wavelength of maximum polarization of more than 400nm and the luminescence factor corrected transmittance Ys is reduced, a decrease in visible light transmittance can be observed. On the other hand, as shown in Table 2, in the test samples of Comparative Examples 2 and 3, Lw and Ls are both 0, indicating that no light is emitted due to ultraviolet irradiation. In addition, it can be seen that since Lw and Ls are detected in Examples 1 to 6 and Comparative Example 1, polarized light is emitted due to ultraviolet irradiation. On the other hand, the luminous brightness in Examples 1 to 6 is higher than that in Comparative Example 1, and its wavelength emits highly polarized light in a wide band range of 400 to 700nm. Furthermore, as shown in Table 3, when Lw and Ls after the light resistance test were confirmed, Examples 1 to 4 had higher light resistance than Comparative Example 1. Therefore, the measured samples of Examples 1 to 4 functioned as polarized light emitting elements that emitted polarized light in the visible light region when irradiated with ultraviolet rays.

[0177] (f) Durability test

[0178] The polarized light-emitting plates obtained in Examples 1 to 6 were placed in an environment of 105°C for 1,000 hours and in an environment of 60°C and 90% relative humidity for 1,000 hours. When durability tests were performed, no decrease in polarization degree or change in polarized light emission was observed. This shows that the polarized light-emitting elements and polarized light-emitting plates of Examples 1 to 6 have high durability even in harsh environments.

[0179] [Industrial Applicability]

[0180] By using the substrate containing the luminescent compound of the present invention or its salt, a polarized light-emitting element and a polarized light-emitting plate having not only a high degree of polarization at the absorption wavelength but also a polarized light-emitting effect can be obtained. Therefore, the polarized light-emitting element and the polarized light-emitting plate using the luminescent compound of the present invention can be applied as a self-luminous polarizing element that plays the role of a polarizing plate in the absorption wavelength and can emit polarized light. In addition, such polarized light-emitting elements and polarized light-emitting plates have excellent durability and high transmittance in the visible light domain. Therefore, the display using the polarized light-emitting element and the polarized light-emitting plate of the present invention can be widely used in televisions, personal computers, tablet computer settings, and transparent displays (perspective displays) and other uses because of the high transparency in the visible light domain and the image caused by polarized light emission that can be displayed for a long time. In addition, since the polarized light-emitting element or its polarized light-emitting plate made using the luminescent compound of the present invention can emit light by ultraviolet light, it can also be applied to displays or media requiring high safety.

Claims

1. A polarized light-emitting element comprising a light-emitting compound represented by the following formula (1) or a salt thereof; In formula (1), k each independently represents an integer of 0 or 1, at least one of X and Y represents a group selected from the group consisting of formulas (2) to (7), and the other X and Y each independently represent a nitro group or a group selected from the group consisting of formulas (2) to (7); M represents a hydrogen atom, a metal ion or an ammonium ion, and m each independently represents an integer of 0 to 2; in formula (2), ※ represents the bonding position of X and Y in formula (1), and Z is a phenyl group which may have a substituent; t represents an integer of 1; In the above formula (3) and formula (4), A is independently selected from the group consisting of a hydrogen atom, a halogen group, a nitro group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms with a sulfonic acid group, an alkyl group having 1 to 4 carbon atoms with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms with a carboxyl group, an alkoxy group having 1 to 4 carbon atoms with a sulfonic acid group, an alkoxy group having 1 to 4 carbon atoms with a hydroxyl group, and an alkoxy group having 1 to 4 carbon atoms with a carboxyl group, and q 1 represents an integer from 0 to 4, M in the above formulae (3) to (7) is as defined in the above formula (1), and M in the formulae (3) to (7) and M in the formula (1) may be the same, and n 1 、n 2 Each independently represents an integer of 0 to 3; * in the above formulae (3) to (7) respectively represents a bonding position in X or Y in the above formula (1).

2. The polarized light emitting element according to claim 1, wherein In the above formula (1), each k is 0, and each of X and Y is any group selected from the group consisting of formulas (2) to (7).

3. The polarized light emitting element according to claim 1, wherein In the above formula (1), each k is 1, and X and Y are each any group selected from the group consisting of formulas (2) to (7). 4 . The polarized light emitting element according to claim 1 , further comprising one or more organic dyes or fluorescent dyes other than the light emitting compound or the salt thereof. 5 . The polarized light emitting element according to claim 1 , further comprising a substrate.

6. The polarized light emitting element according to claim 5, wherein: The substrate comprises a film of a polyvinyl alcohol resin or a derivative thereof. 7 . A polarized light emitting plate comprising a transparent protective film on at least one side of the polarized light emitting element according to claim 1 . 8 . A display device comprising the polarized light emitting element according to claim 1 or the polarized light emitting plate according to claim 7 .

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