CN115004069A

CN115004069A - Optical system and optical device provided with optical system

Info

Publication number: CN115004069A
Application number: CN202180010801.4A
Authority: CN
Inventors: 望月典明
Original assignee: Nippon Kayaku Co Ltd
Current assignee: Nippon Kayaku Co Ltd
Priority date: 2020-02-17
Filing date: 2021-02-16
Publication date: 2022-09-02
Also published as: JPWO2021166907A1; TW202138850A; WO2021166907A1

Abstract

The present invention relates to an optical system including a polarized light emitting element and an optical filter, wherein the polarized light emitting element emits polarized light in a visible light region by absorbing light, the polarized light emitting element being configured to absorb light having a wavelength different from at least a part of a wavelength of light to be emitted, and having axial absorption anisotropy having a light absorption amount different from each other; the optical filter can absorb light in a visible light region with the transmittance of the photometric correction monomer of 45 to 100 percent; and the optical system satisfies the relationship of the formula (1) or (2). A. the _{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

Optical system and optical device provided with optical system

Technical Field

The present invention relates to an optical system that emits polarized light with high luminance, and a display device (display) including the optical system.

Background

A polarizing plate having a light transmitting or shielding function, a Liquid Crystal having a light switching function, and a Display device such as a Liquid Crystal Display (LCD). The application field of the LCD is gradually expanding from small-sized devices such as electronic computers and clocks, which are sold in the market, to notebook computers, document processors, liquid crystal projectors, liquid crystal televisions, car navigators, indoor and outdoor information display devices, measuring devices, and the like. The polarizing plate can be applied to lenses having a polarizing function, and is used for sunglasses with improved visibility, polarizing glasses for 3D televisions, and the like in recent years, and is used for portable information terminals such as wearable terminals, and is partially put into practical use. Polarizing plates have been widely used and used under a wide range of conditions from low temperature to high temperature, low humidity to high humidity, and low light amount to high light amount, and thus polarizing plates having high polarizing performance and excellent durability have been demanded.

In general, a polarizing film constituting a polarizing plate can be produced by dyeing a film base material of polyvinyl alcohol or a derivative thereof with iodine or a dichroic dye (or by adding the above dye to the above base material), and then subjecting the dyed film base material to stretching and orientation; alternatively, the polyene is produced by dehydrochlorination of a polyvinyl chloride film or dehydration of a polyvinyl alcohol film to produce a polyene and oriented. In the polarizing plate comprising such a known polarizing film, a dichroic dye having absorption in the visible light region is generally used, and hence the transmittance is lowered. For example, a typical polarizer commercially available has a transmittance of 35 to 45%.

In addition, in order to express a degree of polarization of 100%, it is necessary to absorb only light of one axis when light of x-axis and y-axis exists in a 2-dimensional plane, in "degree of polarization" which is one index of polarization performance of a polarizing plate. Therefore, a general polarizing plate uses iodine or dichroic dye in order to absorb light of only one axis. When only one-axis light is absorbed, the amount of light that theoretically passes through the polarizing plate is 50% or less with respect to 100% of the incident light amount. In addition, the transmittance is actually lower than 50% due to the decrease in the degree of polarization caused by the poor orientation of iodine or dichroic dyes, the loss of light caused by the film medium, the interfacial reflection on the film surface, and the like, and as a result, the transmittance of the known polarizing plate is as low as 35 to 45%. In order to solve the problem that the transmittance of such a general polarizing plate is as low as 35 to 45%, patent document 1 discloses a technique of an ultraviolet polarizing plate that exhibits a polarizing function while maintaining a certain degree of transmittance in a visible light region. However, the polarizing plate obtained by this technique has high transmittance, but is not capable of providing high degree of polarization in the entire visible light region, and is only applicable to a device for displaying an image using light of around 400 nm.

When a polarizing plate having a low transmittance of light in a visible light region or a polarizing plate having a low degree of polarization is used for a display, for example, the brightness or contrast of the entire display is reduced. In order to solve this problem, methods of obtaining polarization without using a well-known polarizing plate have been studied, and an element (polarized light emitting element) that emits polarized light is described in patent documents 2 to 6 as one of the methods.

[ Prior art documents ]

[ patent document ]

[ patent document 1] WO2005/01527 publication

[ patent document 2] Japanese patent application laid-open No. 2008-224854

[ patent document 3] Japanese patent application laid-open No. 2013-121921

[ patent document 4] WO2011/111607 publication

[ patent document 5] U.S. Pat. No. 3,276,316

[ patent document 6] Japanese patent application laid-open No. 4-226162

[ patent document 7] WO2014/162635 publication

[ patent document 8] WO2007/138980 publication.

[ non-patent document ]

[ non-patent document 1] "application of functional pigment", CMC (stock Co.) publication, No. 1 brush release, Yangtze river, and inspection and repair, pages 98 to 100.

Disclosure of Invention

[ problems to be solved by the invention ]

However, the polarized light emitting elements described in patent documents 2 to 4 are not suitable for mass production because they use special metals, such as rare and expensive metals including lanthanides including europium, and therefore, the manufacturing cost is high and the manufacturing is difficult. In addition, these polarized light emitting devices have low polarization degrees, and thus are difficult to use in displays, and it is difficult to obtain linearly polarized light. Further, since only circular polarized light having a specific wavelength is obtained, applications are limited, and even when the liquid crystal display is used, for example, the luminance and contrast are low, and the design of the liquid crystal cell is difficult. Therefore, there is a strong demand for development of a novel polarizing plate exhibiting a polarized light emission effect, having a high polarized light emission degree and a high transmittance in a visible light region, and being applicable to a liquid crystal display or the like requiring durability in a severe environment, and a material using the same. On the other hand, patent documents 5 and 6 disclose an element that emits polarized light by irradiation with ultraviolet light. However, the light-emitting element has a remarkably low degree of polarization and luminance, and the contrast of each axis of polarized light is low, so that the light-emitting element is not sufficiently used for displays and the like, and the light resistance thereof is low.

The invention aims to provide an optical system which has polarized light emitting function, high polarization degree and high contrast. Another object of the present invention is to provide an optical system having high transparency. Another object of the present invention is to provide a display device using the optical system.

[ means for solving the problems ]

The present inventors have made an effort to achieve the above object, and as a result, have found an optical system including a polarized light emitting element and a filter, wherein the polarized light emitting element emits polarized light in a visible light region by absorbing light, the polarized light emitting element having axes in which at least a part of wavelengths of light to be absorbed and a part of wavelengths of light to be emitted are different and which have different light absorption amounts; the filter absorbs light in a visible light region with a monomer transmittance of 45 to 100% for photometric correction (also called visual sensitivity correction); in addition, the optical system in which the polarized light emitting element and the filter have a specific relationship can provide polarized light emission having high transparency and high contrast.

That is, the present invention is not limited to the following.

[ invention 1] an optical system comprising a polarized light emitting element and a filter, wherein,

the polarized light emitting element emits polarized light in a visible light region by absorbing light, the polarized light emitting element being configured to absorb light having a wavelength different from at least a part of a wavelength of light to be emitted and having axial absorption anisotropy having a different light absorption amount;

the optical filter can absorb light in a visible light region with the transmittance of the photometric correction monomer of 45 to 100 percent; and is

The 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 F represents the absorbance at the maximum absorption wavelength of the axis on which the light absorption amount of the polarized light emitting element is the lowest _em-L Quantum yield, A, representing the axis along which the light absorption of the polarized light-emitting element is the lowest _fi-em-λmax 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)

In the formula, TA _fi-em TAF represents the value obtained by integrating the absorbances of the filters at the respective wavelengths in the wavelength range in which the polarized light emitting element emits light _em-L The value obtained by integrating the absorbance at each wavelength on the axis on which the light absorption amount of the polarized light emitting element is the lowest and the quantum yield on the axis on which the light absorption amount of the polarized light emitting element is the lowest is shown.

[ invention 2] the optical system according to invention 1, which satisfies at least the above formula (2).

[ invention 3] the optical system according to invention 1 or 2, wherein the photometrically corrected monomer transmittance of the aforementioned optical filter is 50 to 99.9%.

[ invention 4] the optical system according to any one of the inventions 1 to 3, wherein the 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 type (3)

In the formula, A _em-L-λmax F represents the absorbance at the maximum absorption wavelength of the axis on which the light absorption amount of the polarized light emitting element is the lowest _em-L Quantum yield of axis representing lowest light absorption amount of polarized light emitting element, A _{Pol-Kz-em-L-λmax} The absorbance of the polarizing element having the wavelength of maximum light emission on the axis on which the amount of light emitted by the polarizing light-emitting element is the weakest is indicated on the highest absorption axis.

[ invention 5] the optical system according to any one of the inventions 1 to 4, wherein the filter is a polarizing element satisfying formula (4):

0<TAF _em-L <0.7×TA _pol-Kz-em formula (4)

In the formula, TA _pol-Kz-em TAF represents the value obtained by integrating the absorbances of the polarizer at the wavelengths of the highest absorption axis in the wavelength range in which the polarized light-emitting device emits light _em-L The expression is the same as in formula (2).

[ invention 6] the optical system according to any one of claims 1 to 5, wherein the filter is a polarizing element, and the polarized light emitting element and the filter are provided so that an axis along which an amount of light emitted by the polarized light emitting element is the weakest and an axis along which an absorbance of the polarizing element is high are parallel to each other.

[ invention 7]]The optical system according to any one of inventions 1 to 6, wherein the color phase of the optical filter is-5<a ^＊ <+3 and b ^＊ <±3。

[ invention 8] the optical system according to any one of the inventions 1 to 7, wherein the polarized light emitting element contains a polarized light emitting pigment, and the polarized light emitting pigment is oriented.

[ invention 9] the optical system according to any one of claims 1 to 8, wherein the polarized light emitting element emits polarized light by absorbing light in an ultraviolet region to a near-ultraviolet visible region.

[ invention 10] the optical system according to any one of the inventions 1 to 9, wherein the polarized light emitting element has a maximum absorption wavelength of light in an ultraviolet region to a near-ultraviolet visible region.

[ invention 11] the optical system according to any one of the inventions 1 to 10, in which the polarized light emitting element and the filter are laminated.

[ invention 12] the optical system according to any one of the inventions 1 to 11, which includes a phase difference plate.

[ invention 13] the optical system according to any one of claims 1 to 12, wherein the optical filter is located on a viewer side.

[ invention 14] A display device provided with the optical system according to any one of invention 1 to 13.

[ Effect of the invention ]

The optical system of the present invention can emit polarized light with high contrast. Certain aspects may further have high transparency. In addition, an aspect can provide high contrast and high transparency in a display device using the optical system.

Drawings

Fig. 1 shows graphs of transmittance (Ky and Kz) of polarized light emitting elements a to C at respective wavelengths.

Fig. 2 is a graph showing the emission intensity ratio of the polarized light emitting panels a to C at each wavelength.

Fig. 3 shows a graph of the polarization degrees of the polarized light emitting panels a to C at respective wavelengths.

Fig. 4 is a graph showing transmittance (Ky and Kz) of the polarizing plates a to E at each wavelength.

Fig. 5 is a graph showing the transmittance of the filters F to H at each wavelength.

Fig. 6 is a graph showing transmittance (Ky and Kz) of the ultraviolet polarizing plate J at each wavelength.

Detailed Description

An optical system of the present invention includes a polarized light emitting element that emits polarized light in a visible light region by absorbing light, the polarized light emitting element having axes in which at least a part of wavelengths of the absorbed light and at least a part of wavelengths of the emitted light are different and which have different absorption amounts of light, and a filter that absorbs light in the visible light region (also referred to as a "visible light absorption filter" or simply a "filter"); the filter absorbs light in a visible light region with a photometric correction monomer transmittance of 45 to 100%; the 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 The absorbance, F, representing the wavelength of maximum absorption on the axis where the light absorption of the polarized light-emitting element is the lowest _em-L Quantum yield, A, representing the axis along which the light absorption of the polarized light-emitting element is the lowest _fi-em-λmax The absorbance of the filter at a wavelength at which the polarized light emitting element exhibits a maximum light emission wavelength is shown.

0<TAF _em-L <0.7×TA _fi-em Formula (2)

In the formula, TA _fi-em TAF represents the value obtained by integrating the absorbances of the filters at the respective wavelengths in the wavelength range in which the polarized light emitting element emits light _em-L The value obtained by integrating the product of the absorbance at each wavelength on the axis on which the light absorption amount of the polarized light-emitting element is the lowest and the quantum yield on the axis on which the light absorption amount of the polarized light-emitting element is the lowest in the light absorption wavelength range of the polarized light-emitting element is expressed.

Here, "the wavelength of the absorbed light and at least a part of the wavelength of the emitted light are different" means that the wavelength region of the light absorbed by the polarized light emitting element and the wavelength region of the light emitted by the polarized light emitting element are different entirely or partially. The term "polarized light capable of emitting light in the visible light region by absorbing light" means an element capable of emitting light by polarization by absorption of light and emitting light polarized at least in the wavelength range of 400 to 700 nm. Further, although 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 referred to as a wavelength conversion element, in the claims and the specification of the present application, the element is referred to as a "polarized light emitting element" in terms of a point at which the absorbed light is converted into light that is polarized.

The polarized light-emitting element used in the present invention includes a compound having a function of absorbing light in the element (for example, a polarized light-emitting dye described later), and is not particularly limited as long as it can emit polarized light by utilizing a light wavelength conversion function of the compound or can be formed as a layer using a compound having a function of emitting polarized light. If the light-emitting element is limited to have a light-absorbing effect at a specific wavelength, the light-emitting element can be optically designed to transmit light other than the specific wavelength, and can be provided without being limited to the entire wavelength range of visible light, and the light-emitting element can have a high transmittance only at the specific wavelength. It is particularly preferable that the element which absorbs light and emits polarized light has an absorption wavelength in a range from an ultraviolet region to a near ultraviolet visible region, and the light-emitting element can emit light by light invisible to the eye or a light source which is difficult to see by the absorption wavelength of light in the range from the ultraviolet region to the near ultraviolet visible region, and an element which has high transmittance in visual perception and emits polarized visible light can be provided. As a more preferred form of the polarized light emitting element that emits polarized light, one of the more preferred forms of the present application may be: the absorption region of light is at least in the ultraviolet region to near ultraviolet visible region, for example, 300 to 430nm, and the emission wavelength of polarized light has an emission wavelength at least in the wavelength range of 400 to 700nm in the visible region.

The polarized light emitting element used in the present invention is an element that absorbs light in a range from an ultraviolet region to a near ultraviolet visible region and emits polarized light having a peak in an emission spectrum at least in a part or the whole of the visible region in a range from 400 to 700 nm. In the present application, light in the ultraviolet region to the near-ultraviolet visible region, that is, light of 300 to 430nm, which is light invisible to human eyes or light difficult to clearly see, is more preferable. In addition, from the viewpoint of improving visibility, the absorption wavelength of light of the polarized light emitting element is more preferably 340 to 420nm, still more preferably 350 to 410nm, particularly preferably 350 to 400 nm. The light irradiated to the ultraviolet region to the near-ultraviolet visible region of the polarized light emitting element may have polarized light, regardless of whether the light is polarized or not. One of the methods for obtaining the above-described polarized light-emitting device can be obtained by including at least a substrate and a polarized light-emitting dye, which will be described later.

The polarized light emitted by the polarized light emitting element used in the present invention includes: linearly polarized light, circularly polarized light, elliptically polarized light, and the like, but linearly polarized light is more preferable from the viewpoint of design of the display device. The linearly polarized light may be a wave in a constant axial direction. The display device such as a liquid crystal display can be easily designed by linearly polarizing light by the polarized light emitting element, that is, by emitting light polarized on one axis. In this case, the commercially available liquid crystal display and polarizing lens are also used in industrial fields, since iodine-based polarizing plates or dye-based polarizing plates corresponding to linear polarization are used in many cases.

In order to emit light polarized in a straight line, for example, it is possible to orient polarized luminescent dyes, which will be described later, in the same direction in the base material. In addition, the polarized light emitting dye can emit polarized light having the same axis by further orienting the polarized light emitting dye on the same axis, and the intensity of light propagating the polarized light emitting dye is increased. That is, when the polarized luminescent pigment is oriented in the same direction in the base material, linearly polarized light of higher brightness can be provided. Further, the linear polarizing plate can be changed to various polarizations by combining the phase difference plates, and the optical design can be facilitated. For example, circularly polarized light may be emitted by providing an 1/4 λ plate for the emission wavelength, or linearly polarized light emitted may be rotated by 90 ° by providing a 1/2 λ plate for the emission wavelength. As described above, since the polarization can be variously adjusted by the retardation plate, the provision of the retardation plate for the polarized light emitting element is a preferred embodiment of the present application.

Examples of the polarized light emitting element that can be used in the present invention include: the optical film contains a polarized light emitting dye, and linearly polarized light emission is performed by orienting the polarized light emitting dye, and axial absorption anisotropy is exhibited at the wavelength of absorbed light. The axial absorption anisotropy means that the axis having strong absorption and the axis having weak absorption are present. For example, when the polarized light emitting element absorbs light in the ultraviolet region to the near-ultraviolet visible region and emits polarized light in the visible region by using the absorbed light, a phenomenon is shown in which the orientation direction of the polarized light emitting dye in the absorbed light and the amount of light absorbed in a direction different from the orientation direction are different. In general, having such axial absorption anisotropy is also referred to as having dichroism. The magnitude of axial absorption anisotropy (dichroism) obtained by orienting the polarized light-emitting dye shows a dichroic ratio (hereinafter, also referred to as "RD"). The dichroic ratio is a ratio of an absorption amount of the axis having the highest absorption to an absorption amount of the axis having the lowest absorption, and is usually 3 or more, and preferably higher, more preferably 5 or more, still more preferably 10 or more, particularly preferably 20 or more, and still more preferably 30 or more, to exhibit a dichroic ratio (axial absorption anisotropy). About 50 indicates that light having a high degree of polarization (or polarization ratio) is emitted, and about 70 indicates that the dichroic ratio (anisotropy) is more exhibited, and that the dichroic ratio also exhibits a polarized light having a higher degree of polarization. The degree of orientation of the pigment [ hereinafter, referred to as Order Parameter (Order Parameter) ] can also be calculated from the value of the dichroic ratio. The orientation degree of the dye is a value calculated by the following formula (5), and is more preferably 0.80 to 1.00, particularly preferably 0.9 to 1.00.

Order Parameter (RD-1)/(RD +2) formula (5)

(method for manufacturing polarized light emitting element)

The method for manufacturing the polarized light emitting element of the present invention can be manufactured, for example, by the following steps: preparing a base material; a swelling step of immersing the base material in a swelling solution to swell the base material; a dyeing step of immersing the swelled base material in a dyeing solution containing at least one or more of the above polarized luminescent pigments to adsorb the polarized luminescent pigments on the base material; a crosslinking step of immersing the base material having the polarized light emitting dye adsorbed thereon in a solution containing boric acid to crosslink the polarized light emitting dye in the base material; an extension step of uniaxially extending the base material in which the polarized light emitting pigments have been crosslinked in a predetermined direction to align the polarized light emitting pigments in the predetermined direction; further optionally washing and/or drying the extended substrate with a washing liquid; the foregoing drying step dries the washed substrate.

< substrate >)

The substrate may be a polymer film for adsorbing and orienting a polarized light-emitting dye described later. The polymer film is preferably a hydrophilic polymer film obtained by forming a film of a hydrophilic polymer capable of adsorbing a polarizing luminescent dye having general dichroism, and more preferably a hydrophilic polymer film obtained by forming a film of a hydrophilic polymer capable of adsorbing a dye having a stilbene skeleton or a dye having a biphenyl skeleton. The hydrophilic polymer is not particularly limited, but for example, a polyvinyl alcohol resin and a starch resin are preferable, and a polyvinyl alcohol resin and derivatives thereof are more preferable from the viewpoint of the dyeing property, processability, crosslinking property, and the like of the polarizing luminescent dye having dichroism. Examples of the polyvinyl alcohol resin and derivatives thereof include: polyvinyl alcohol or a derivative thereof, and any of these modified with an olefin such as ethylene or propylene, or an unsaturated carboxylic acid such as crotonic acid, acrylic acid, methacrylic acid, or maleic acid. Among them, films made of polyvinyl alcohol resins and derivatives thereof are suitably used in view of their adsorptivity and orientation of dichroic polarizing luminescent dyes. The substrate may be a film made of a commercially available polyvinyl alcohol resin or a derivative thereof, or may be produced by forming a film of a polyvinyl alcohol resin. The method for forming the film of the polyvinyl alcohol resin is not particularly limited, and for example, the following methods can be used: known film-forming methods are disclosed, for example, a method of melt-extruding hydrous polyvinyl alcohol, a method of spreading a film, a wet-type film-forming method, a gel-type film-forming method (in which an aqueous polyvinyl alcohol solution is once cooled to gel and then the solvent is removed by extraction), a casting film-forming method (in which an aqueous polyvinyl alcohol solution is spread on a base and dried), and a method of combining these methods. The thickness of the substrate is usually 10 to 100. mu.m, preferably 20 to 80 μm or so.

The following describes a method for producing a polarized light emitting device, taking as an example the case of using a film made of a polyvinyl alcohol resin and a derivative thereof.

(swelling step)

The swelling step is preferably carried out by immersing the substrate in a swelling solution at 20 to 50 ℃ for 30 seconds to 10 minutes, and the swelling solution is more preferably water. The stretch ratio of the substrate is adjusted to 1.00 to 1.50 times more preferably, and is adjusted to 1.10 to 1.35 times more preferably.

(dyeing step)

The dyeing step is a step of allowing the base material obtained through the swelling step to adsorb one or more polarized luminescent dyes described later. The dyeing step is not particularly limited as long as the method of allowing the polarized light-emitting dye to be adsorbed on the substrate is possible, and examples thereof include: a method of immersing a substrate in a dyeing solution containing a polarized luminescent pigment; or a method of applying a dyeing solution containing a polarized light-emitting pigment to a substrate, but a method of immersing in a dyeing solution containing a polarized light-emitting pigment is more preferable. The concentration of the polarized light-emitting dye in the dyeing solution is not particularly limited as long as the polarized light-emitting dye is sufficiently adsorbed in the base material, but for example, the concentration of the polarized light-emitting dye in the dyeing solution is preferably 0.0001 to 1% by mass, more preferably 0.0001 to 0.5% by mass. The temperature of the dyeing solution in the dyeing step is more preferably 5 to 80 ℃, more preferably 20 to 50 ℃, particularly preferably 40 to 50 ℃. The time for immersing the base material in the dyeing solution may be appropriately adjusted, but is preferably adjusted to 30 seconds to 20 minutes, and more preferably 1 to 10 minutes. The polarizing luminescent pigment contained in the dyeing solution can be used alone in 1 kind, or can be used in combination in more than 2 kinds. Since the polarized luminescent pigments differ in luminescent color due to differences in pigment structure or the like, the luminescent color produced can be appropriately adjusted to various colors by incorporating 2 or more kinds of the polarized luminescent pigments in the base material. Further, the dyeing solution may further contain 1 or more kinds of organic dyes and/or fluorescent dyes, as necessary, in addition to the polarized light emitting dye.

(polarizing luminescent pigment)

Examples of the polarized light-emitting dye include: the compound having at least either a stilbene skeleton or a biphenyl skeleton in the molecule in the structure and emitting light by the absorbed light or a salt thereof preferably emits fluorescence or phosphorescence. The polarized light emitting pigment has fluorescence emitting function, and the pigment has dichroic ratio at light absorption wavelength, so that polarized light can be emitted. In particular, a polarized light-emitting dye having a stilbene skeleton or biphenyl skeleton in a dye molecule has excellent fluorescence emission characteristics and a high dichroic ratio at an absorption wavelength by orienting the dye. These characteristics are derived from the characteristics of each of the above skeletons, and these characteristics can be further improved, and an arbitrary substituent can be further introduced into each of the skeletons for the purpose of adjusting various characteristics such as absorption wavelength, emission wavelength, fastness to light, moisture, ozone gas, and various other properties, and solubility. When the type of the substituent or the substitution position is not preferably selected among the substituents, there is a case where a problem such as a significant decrease in the amount of emitted light occurs even when a high degree of polarization is achieved as in the case of a known dye-based polarizing plate, and therefore, the selection of the type of the substituent or the substitution position is particularly important in order to obtain excellent fluorescence emission characteristics and a high dichroic ratio. The polarized light-emitting dye may be used alone in 1 kind or in combination with 2 or more kinds.

(a) Polarized light luminescent pigment with stilbene skeleton

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

In the formula (S), L and M each independently represent a nitro group, an amino group which may have a substituent, a carbonylamino 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 amido group which may have a substituent, a ureido group which may have a substituent, an aryl group which may have a substituent, a carbonyl group which may have a substituent.

It is known that the dye having a stilbene skeleton represented by the above formula (S) has fluorescence emission and can obtain dichroism by orientation, but this is mainly derived from the stilbene skeleton, and an arbitrary substituent may be further introduced.

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

Examples of the carboxyalkyl group include: methylcarboxyl, ethylcarboxyl, and the like. Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, iodine atom, etc. Examples of alkoxy groups include: methoxy, ethoxy, propoxy, and the like. Examples of aryloxy groups include: phenoxy, naphthoxy, and the like.

Examples of the above-mentioned carbonylamino group which may have a substituent include: n-methyl-carbonylamido (-CONHCH) ₃ ) N-ethyl-carbonylamido (-CONHC) ₂ H ₅ ) N-phenyl-carbonylamido (-CONHC) ₆ H ₅ ) And the like.

Examples of the above-mentioned naphthotriazolyl group which may have a substituent include: benzotriazolyl, naphthotriazolyl, and the like.

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 alkyl groups such as isopropyl, sec-butyl, and tert-butyl; and cyclic alkyl groups such as cyclohexyl and cyclopentyl.

Examples of the above vinyl group which may have a substituent include: vinyl, methylvinyl, ethylvinyl, divinyl, pentadienyl, and the like.

Examples of the amide group which may have a substituent include: acetamido (-NHCOCH) ₃ ) Benzamido (-NHCOC) ₆ H ₅ ) And the like.

Examples of the above aryl group which may have a substituent include: phenyl, naphthyl, anthracenyl, biphenyl, and the like.

Examples of the above-mentioned carbonyl group which may have a substituent include: methylcarbonyl, ethylcarbonyl, n-butylcarbonyl, phenylcarbonyl, and the like.

The substituent in the carbonyl amide group which may have a substituent, the naphthotriazole group which may have a substituent, the alkyl group having 1 to 20 carbon atoms which may have a substituent, the vinyl group which may have a substituent, the amide group which may have a substituent, the urea group which may have a substituent, the aryl group which may have a substituent, and the carbonyl group which may have a substituent is not particularly limited, but may be the same as the substituent described in the paragraph of the amino group which may have a substituent.

The pigment having a stilbene skeleton represented by the above formula (S) is particularly preferably a pigment represented by the following formula (S-a) or a salt thereof or a pigment represented by the following formula (S-b) or a salt thereof. By using these pigments, it is possible to obtain a polarized light emitting element which emits white light, for example, by emitting light of various colors by combining a plurality of the pigments.

In the formula (S-a), 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 amine group which may have a substituent, and n represents an integer of 0 to 3.

In the formula (S-b), 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.

In the above formula (S-a), 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 above paragraph for the alkyl group of carbon number 1 to 20 which may have a substituent. The alkoxy group which may have a substituent is more preferably a methoxy group, an ethoxy group or the like. 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, a phenylamino group or the like. 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 the 1-position and the 2-position, it is more preferable to bond to the 3-, 5-or 8-position. n is an integer of 0 to 3, preferably 1 or 2. - (SO) ₃ H) The group may be bonded to any carbon of the naphthalene ring in the naphthotriazole ring. Is in- (SO) ₃ H) In the case where n is 1 and the carbons condensed with the triazole ring are the 1-and 2-positions, the 4-, 6-or 7-position is more preferable; in the case where n is 2, 5-and 7-bits, and 6-and 8-bits are more preferable; in the case where n is 3, a combination of 3 bits and 6 and 8 bits is more preferable. In addition, R is particularly preferably a hydrogen atom and n is 1. X represents a nitro group or an amino group which may have a substituent, and a nitro group is more preferable. The amino group which may have a substituent may be the same as described above, and the number of carbon atoms 1 which may have a substituent is more preferableAlkylcarbonylamino group to 20, arylcarbonylamino group which may have a substituent, alkylsulfonylamino group of carbon numbers 1 to 20, or arylsulfonylamino group which may have a substituent.

Y in the above formula (S-b) is preferably an optionally substituted aryl group, more preferably an optionally substituted naphthyl group, particularly preferably a naphthyl group substituted with an amino group and a sulfo group as substituents. Z represents the same substituent as described for X in the above formula (S-a), and a nitro group is more preferable.

Examples of the compound represented by the above formula (S) include: kayaphor series (manufactured by Nippon chemical Co., Ltd.) and Whitex series (manufactured by Sumitomo chemical Co., Ltd.) such as Whitex RP. The compound represented by the formula (S) is exemplified below, but not limited thereto.

(b) Polarized light luminescent pigment with biphenyl skeleton

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

In formula (B), P and Q each independently represent a nitro group, an amino group which may have a substituent, a carbonylamino 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 amido group which may have a substituent, a urea group which may have a substituent, an aryl group which may have a substituent, a carbonyl group which may have a substituent.

In the formula (B), P and Q each independently represent a nitro group, an amino group which may have a substituent, a carbonylamido 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 amido group which may have a substituent, a ureido group which may have a substituent, an aryl group which may have a substituent, a carbonyl group which may have a substituent, but are not necessarily limited thereto. The amino group which may have a substituent, the carbonylamide group which may have a substituent, the naphthotriazole group which may have a substituent, the alkyl group having 1 to 20 carbon atoms which may have a substituent, the vinyl group which may have a substituent, the amide group which may have a substituent, the aryl group which may have a substituent and the carbonyl group which may have a substituent may be respectively the same as described above.

The compound represented by the above formula (B) is preferably a compound represented by the following formula (B-a).

In the formula (B-a), R ₁ 、R ₂ 、R ₃ And R ₄ Each independently represents 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 carboxamide group, a sulfonamide group, a carboxyalkyl group, and j or k each independently represents an integer of 0 to 2.

- (SO) in the above formula (B-a) ₃ H) The more preferable substitution position of the group is not particularly limited, but when the vinyl group is at the 1-position, the 2-position and the 4-position are more preferable, and the 2-position is particularly preferable.

In the above formula (B-a), the carboxyalkyl group may be the same as described above.

Examples of the alkyl group having 1 to 4 carbon atoms include: methyl, ethyl, propyl, n-butyl, sec-butyl, tert-butyl, cyclobutyl and the like. Examples of the alkoxy group having 1 to 4 carbon atoms include: methoxy, ethoxy, propoxy, n-butoxy, sec-butoxy, tert-butoxy, cyclobutoxy, and the like. 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 above alkylsulfonyl group having 1 to 4 carbon atoms include: methylsulfonyl, ethylsulfonyl, propylsulfonyl, n-butylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, cyclobutylsulfonyl, and the like. Examples of the above arylsulfonyl group having 6 to 20 carbon atoms include: phenylsulfonyl, naphthylsulfonyl, biphenylsulfonyl, and the like.

In the above formula (B-a), R is ₁ To R ₄ More preferred substitution positions are 2-position and 4-position, when the vinyl group is 1-position, more preferred.

The method for synthesizing the polarized luminescent dye represented by the above formula (B-a) can be known, and can be obtained, for example, by condensing 4-nitrobenzaldehyde-2-sulfonic acid with phosphonate and then reducing the nitro group.

As the compound represented by the formula (B), compounds described in patent document 6 and the like can be used, and the following compounds and the like are specifically exemplified.

(c) Luminescent pigments having a coumarin skeleton

The compound having a coumarin skeleton which is a luminescent dye is preferably a compound represented by the following formula (C) or a salt thereof.

In the 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 of 1 to 3. The coumarin-based compound represented by the formula (C) represents a water-soluble luminescent dye having a coumarin skeleton.

The above formula (C) is preferably exemplified because the contrast in the case of bias light emission is further improved in the case of the following formula (C-a). In formula (C-a), the radical R ₅ And R ₆ Each independently represents 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 of 1 to 3.

As described above, the luminescent dye belonging to the water-soluble coumarin compound represented by the formula (C) or the formula (C-a) in the present invention has at least 1 coumarin skeleton in the molecule. The luminescent dye belonging to the water-soluble coumarin compound of the present invention has a coumarin skeleton, and therefore exhibits a polarized luminescence effect by irradiation with ultraviolet light and visible light (specifically, light of 300 to 600 nm).

The salts of the compounds represented by the above formulae (S), (B) and (C) are salts formed together with an inorganic cation or an organic cation. Examples of the inorganic cationic alkali metal include: cations such as lithium, sodium, and potassium, and ammonium ion (NH) ₄ ⁺ ). Examples of the organic cation include organic ammonium represented by the following formula (A).

In the formula (A), from Z ₁ To Z ₄ Each independently represents a hydrogen atom, an alkyl group, a hydroxyalkyl group, or a hydroxyalkoxyalkyl group, Z ₁ To Z ₄ At least one of the above groups is a group other than a hydrogen atom.

From Z ₁ To Z ₄ Specific examples thereof include C such as methyl, ethyl, butyl, pentyl and hexyl ₁ -C ₆ Alkyl, more preferably C ₁ -C ₄ An alkyl group; hydroxy group C such as hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl and 2-hydroxybutyl ₁ -C ₆ Alkyl, more preferably hydroxy C ₁ -C ₄ An alkyl group; and a hydroxy group C such as a hydroxyethoxymethyl group, a 2-hydroxyethoxyethyl group, a 3-hydroxyethoxypropyl group, a 3-hydroxyethoxybutyl group and a 2-hydroxyethoxybutyl group ₁ -C ₆ Alkoxy radical C ₁ -C ₆ Alkyl, more preferably hydroxy C ₁ -C ₄ Alkoxy radical C ₁ -C ₄ Alkyl groups, and the like.

Among these inorganic cations and organic cations, more preferable are: sodium ion, potassium ion, lithium ion, monoethanol ammonium ion, diethanol ammonium ion, triethanol ammonium ion, monoisopropanol ammonium ion, diisopropanol ammonium ion, triisopropanol ammonium ion, and ammonium cation. Among these, lithium ion, ammonium ion and sodium ion are more preferable.

Other polarized light-emitting dyes that can be used in the above polarized light-emitting element include, for example: c.i. fluorescent Brighter 5, c.i. fluorescent Brighter 8, c.i. fluorescent Brighter 12, c.i. fluorescent Brighter 28, c.i. fluorescent Brighter 30, c.i. fluorescent Brighter 33, c.i. fluorescent Brighter 350, c.i. fluorescent Brighter 360, c.i. fluorescent Brighter 365, and the like. These fluorescent dyes may be free acids or salts of alkali metal salts (e.g. Na, K, Li), ammonium or amines.

The polarized light emitting pigments may be oriented by 1 kind alone or 2 or more kinds in combination. When 2 or more kinds of the polarizing luminescent dyes are used in combination, various luminescent colors can be adjusted by adjusting the blending ratio between the polarizing luminescent dyes. For example, by using the chromaticity a ^＊ Value and b ^＊ The absolute value of the value is adjusted to be 5 or less, so that the polarized light emitted by the polarized light emitting element is white. The above chromaticity a ^＊ Value and b ^＊ The value is based on the spectral distribution measured for the light emitted from the polarized light-emitting element when the light is made incident on each polarized light-emitting element, and is calculated in accordance with JIS Z8781-4: 2013. According to JIS Z8781-4: 2013 corresponds to the object color expression method defined by the international commission on illumination (abbreviated as "CIE"). Chroma a ^＊ Value and b ^＊ The measurement of the value is usually performed by irradiating the measurement sample with natural light, but in the specification and claims of the present application, the chromaticity a can be determined by irradiating the polarized light emitting element with light of a short wavelength such as the ultraviolet region and measuring the emitted light ^＊ Value and b ^＊ The value is obtained. A of the emitted light ^＊ Is 5 or less, more preferably 4 or less, still more preferably 3 or less, and yet more preferably2 or less, particularly preferably 1 or less. In addition, b of the emitted light ^＊ The absolute value of (b) is 5 or less, more preferably 4 or less, still more preferably 3 or less, still more preferably 2 or less, particularly preferably 1 or less. If a ^＊ Value and b ^＊ When the absolute values of the values are 5 or less independently of each other, the white color is perceived by human eyes, and when the absolute values are 5 or less, the white color is perceived as more preferable white light emission. Since the emitted polarized light is white, the light can be used as a natural light source such as sunlight or a light source of a paper white terminal, and the light can be easily applied even when the light is placed in a display using a color filter or the like. If the light intensity is perceived by the eyes as emitting light, the application to a display is not problematic. In particular, it is important for the present application that the emitted light has a high degree of polarization and a high transmittance in the visible light region.

(D) Other pigments

The polarized light emitting element preferably contains a single or a plurality of dyes or salts thereof having a stilbene skeleton, a biphenyl skeleton or a coumarin skeleton, and may further contain one or more kinds of other organic dyes or other fluorescent dyes as needed for the purpose of color adjustment or the like within a range not to inhibit the polarized light emitting function. The other organic dye is not particularly limited as long as it can control the color (hue) or emission color of the polarized light emitting element, but is preferably a dye having high dichroism and having little influence on the polarization of the ultraviolet ray region of the stilbene skeleton or biphenyl skeleton. Examples of such other organic dyes include: c.i. direct yellow 12, c.i. direct yellow 28, c.i. direct yellow 44, c.i. direct orange 26, c.i. direct orange 39, c.i. direct orange 71, c.i. direct orange 107, c.i. direct red 2, c.i. direct red 31, c.i. direct red 79, c.i. direct red 81, c.i. direct red 247, c.i. direct blue 69, c.i. direct blue 78, c.i. direct green 80 and c.i. direct green 59. These organic dyes may be free acids or may be alkali metal salts (e.g. Na, K, Li), ammonium salts or salts of amines. The other fluorescent dyes are not particularly limited, and the disclosed fluorescent dyes can be generally used for the purpose of adjusting the emission color.

When the other organic dye or the other fluorescent dye is used in combination, the dye to be blended may be selected and the blending ratio may be adjusted in order to adjust the color of the desired polarized light emitting element. The blending ratio of the organic dye or the fluorescent dye is not particularly limited depending on the purpose of the preparation, 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 with respect to 100 parts by mass of the polarized light emitting element.

The dyeing solution may contain a dyeing assistant, if necessary, in addition to the dyes described above. Examples of the dyeing assistant include: sodium carbonate, sodium hydrogen carbonate, sodium chloride, sodium sulfate (mirabilite), anhydrous sodium sulfate, sodium tripolyphosphate, and the like, and sodium sulfate is more preferable. The content of the dyeing assistant may be arbitrarily adjusted depending on the dyeing property of the dye to be used, the above-mentioned dipping time, the temperature of the dyeing solution, and the like, but is more preferably 0.0001 to 10% by mass, and still more preferably 0.0001 to 2% by mass in the dyeing solution.

After the dyeing step, a preliminary washing step may be optionally performed in order to remove the dyeing solution attached to the surface of the base material in the dyeing step. By performing the preliminary washing step, migration of the dye remaining on the surface of the substrate into a liquid to be treated later can be suppressed. For the preliminary washing step, water is generally used as the washing liquid. The washing method is more preferably a method of immersing the dyed substrate in a washing liquid, but the substrate may be washed by applying a washing liquid thereto. The washing time is not particularly limited, but is preferably 1 to 300 seconds, 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 is not dissolved, and the washing treatment is generally applied at 5 to 40 ℃. In addition, even if the pre-washing step is not performed, the performance of the polarized light emitting element is not particularly greatly affected, and therefore the pre-washing step can be omitted.

(crosslinking step)

After the dyeing step or the preliminary washing step, the base material may contain a crosslinking agent. The method of containing the crosslinking agent in the base material is more preferably a method of immersing the base material in a treatment solution containing the crosslinking agent, and the treatment solution may be applied or coated on the base material. 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 preferable. The concentration of boric acid in the treatment solution is more preferably 0.1 to 15 mass%, and still more preferably 0.1 to 10 mass%. The temperature of the treatment solution is more preferably 30 to 80 ℃ and still more preferably 40 to 75 ℃. In addition, the treatment time of the crosslinking step is more preferably 30 seconds to 10 minutes, and still more preferably 1 to 6 minutes. The method for manufacturing a polarized light emitting device of the present invention has the crosslinking step, and thus the obtained polarized light emitting device has a high degree of polarization of light emitted, and shows a high contrast as a display. Such an effect is an excellent effect which is not expected at all from the function of boric acid used in the well-known art for the purpose of improving water resistance or light transmittance. In the crosslinking step, an aqueous solution containing a cationic polymer compound may be further combined and subjected to fixation (fix) treatment, if necessary. By this fixation treatment, the dye in the polarized light emitting element can be immobilized. In this case, as the cationic polymer compound, for example, a cation; dicyanamides and fumagillin polycondensates can be used as dicyanamides; the polyamine can be dicyandiamide/diethylenetriamine polycondensate; as the polycation, epichlorohydrin/dimethylamine addition polymer, dimethyldiallylammonium chloride/dioxide ion copolymer, diallylamine salt polymer, dimethyldiallylammonium chloride polymer, allylamine salt polymer, dialkylaminoethylacrylate quaternary salt polymer, etc. can be used.

(elongation step)

After the above-mentioned crosslinking step, an elongation step is carried out. The stretching step is performed by uniaxially stretching the base material in a predetermined direction, and may be performed by either a wet stretching method or a dry stretching method. The draw ratio is preferably 3 times or more, more preferably 5 to 8 times.

In the wet stretching method, it is preferable that the base material is stretched in water, a water-soluble organic solvent, or a mixed solution thereof. More preferably, the substrate is immersed in a solution containing at least 1 crosslinking agent and simultaneously subjected to the stretching treatment. The crosslinking agent may be boric acid in the crosslinking agent step, and it is more preferable that the extension treatment is carried out in the treatment solution used in the crosslinking step. The stretching temperature is more preferably 40 to 70 ℃ and still more preferably 45 to 60 ℃. The extension time is usually 30 seconds to 20 minutes, more preferably 2 to 7 minutes. The wet extension step may be performed by one-stage extension, or may be performed by multi-stage extension with two or more stages. In addition, the stretching treatment may be optionally performed before the dyeing step, and in this case, the orientation of the dye may be performed at the same time as the dyeing.

In the dry stretching method, when the stretching heating medium is an air medium, it is preferable to stretch the base material at a temperature of the air medium of from room temperature to 180 ℃. In addition, humidity is preferably in an environment of 20 to 95% RH. Examples of the method of heating the substrate include: the inter-roll zone stretching method, the roll heating stretching method, the hot press stretching method, the infrared heating stretching method, and the like, but the method is not limited to these stretching methods. The dry extension step may be performed by one-stage extension, or may be performed by multi-stage extension with two or more stages.

(washing step)

In the above-mentioned extension step, the surface of the substrate may be washed by adhering the deposition of the crosslinking agent or foreign matter thereto. The washing time is preferably 1 second to 5 minutes. The cleaning method is preferably a method of immersing the substrate in a cleaning solution, and the substrate may be cleaned by applying or coating the cleaning solution to the substrate. The washing liquid is preferably water. The washing treatment may be carried out in one stage, or may be carried out in a plurality of stages including 2 or more stages. The temperature of the washing solution in the washing step is not particularly limited, but is usually 5 to 50 ℃, preferably 10 to 40 ℃, and may be room temperature.

The solvent of the solution or the treatment solution used in each step may be, for example, water other than the above water: alcohols such as dimethyl sulfoxide, N-methylpyrrolidone (Methyl pyrrolidone), methanol, ethanol, propanol, isopropanol, glycerol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane; amines such as ethylenediamine and diethylenetriamine, and the like. The solvent of the solution or the treatment solution is not limited to these, but water is most preferable. The solvent for these solutions or treatment solutions may be used alone in 1 kind, or may be a mixture of 2 or more kinds.

(drying step)

After the washing step, a drying step of the substrate is performed. The drying treatment may be performed by natural drying, but in order to further improve the drying efficiency, the drying treatment may be performed by removing moisture and the like on the surface by roll compression, an air knife, a water suction roll, or the like, or may be performed by air-blow drying. The temperature of the drying treatment is preferably 20 to 100 ℃ but more preferably 60 to 100 ℃. The drying time is more preferably 30 seconds to 20 minutes, and still more preferably 5 to 10 minutes.

The above method is an example of a method for manufacturing a polarized light emitting element that can be used in the present invention. Since each of the dyes is not decomposed even in a high-temperature or high-humidity environment, a polarized light emitting element having high durability can be obtained.

In a polarized light-emitting element including the polarized light-emitting dye used in the present invention, for example, a compound or a salt thereof which has at least one of the above-mentioned stilbene skeleton, biphenyl skeleton or coumarin skeleton in the structure and emits fluorescence, which is more preferable, the polarized light-emitting dye used in the present invention can emit polarized light in the visible light region by absorbing light in the ultraviolet region to the near-ultraviolet visible light region by irradiation with light in the ultraviolet region to the near-ultraviolet visible light region, or the like, that is, irradiation with light in the non-visible light region. Since the polarized light emitting element emits polarized light in the visible light region, when the polarized light emitting element is observed with a general polarizing plate interposed therebetween, the light of the polarized light in the visible light region can be visually recognized by changing the angle of the axis of the polarizing plate, and the light of the strong light emission axis and the light of the weak light emission axis (or the light of the non-light emission axis) can be visually recognized. The polarization degree of polarization of light emitted by the polarized light emitting element is 70% or more and 100% or less, more preferably 80% or more, still more preferably 90% or more, still more preferably 95% or more, and particularly preferably 98% or more.

The polarized light-emitting dye used in the present invention is preferably a polarized light-emitting dye used in the present invention, for example, a polarized light-emitting element having at least one of the above-described stilbene skeleton, biphenyl skeleton and coumarin skeleton in its structure and containing a compound that emits fluorescence or a salt thereof can transmit light in a visible light region without absorbing the light. That is, the transmittance in the visible light region of the polarized light emitting element can be made high by the transmittance corrected by the light intensity, and the transmittance can be made 30 to 35% higher than the parallel transmittance in the case of using a general polarizing plate configuration for the liquid crystal display. In the polarized light emitting element used in the present application, when the monomer transmittance by the photometric correction is 50% or more, a liquid crystal display having significantly and dramatically high transmittance as compared with a known liquid crystal display can be obtained, and is preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, and particularly preferably 90% or more. The above-mentioned polarized light-emitting element having at least one of a stilbene skeleton, a biphenyl skeleton and a coumarin skeleton in its structure and containing a compound which emits fluorescence or a salt thereof is preferably a polarized light-emitting element which has a small absorption in a visible light region in a non-light-emitting state and has a high transparency in appearance, and can provide a polarized light-emitting element having high brightness because it emits light of polarized light having high brightness in terms of light emission.

[ polarizing light-emitting sheet ]

The above polarized light emitting element may be further provided with a transparent protective film to form a polarized light emitting panel having a transparent protective film. The transparent protective film is used for improving the durability, operability, and the like of the polarized light emitting element, and does not affect the axial absorption anisotropy or polarized light emission exhibited by the polarized light emitting element at all. The transparent protective film may be provided on both surfaces of the polarized light emitting element, but may be provided only on either surface, that is, may be provided only on either one surface.

The transparent protective film is preferably a transparent protective film having excellent optical transparency and mechanical strength. The transparent protective film is preferably a film having a layer shape capable of maintaining the film shape, and more preferably a plastic film having excellent thermal stability, moisture barrier properties, and the like in addition to transparency and mechanical strength. Examples of the material for forming such a transparent protective film include: cellulose acetate films, acrylic films, fluorine films such as tetrafluoroethylene/hexafluoropropylene copolymers, films made of polyester resins, polyolefin resins, or polyamide resins, and the like, and triacetyl cellulose (TAC) films or cycloolefin films are preferably used. The thickness of the transparent protective film is more preferably in the range of 1 μm to 200 μm, still more preferably in the range of 10 μm to 150 μm, particularly preferably in the range of 40 μm to 100 μm. The method for providing the transparent protective film on the polarized light-emitting element is not particularly limited, but for example, the transparent protective film may be stacked on the polarized light-emitting element and laminated in a publicly known manner.

The polarized light emitting panel can be further provided with an adhesive layer for respectively adhering the transparent protective film and the polarized light emitting element. The adhesive constituting the adhesive layer is not particularly limited, but examples thereof include: polyvinyl alcohol adhesives, amine ester emulsion adhesives, acrylic adhesives, polyester/isocyanate adhesives, and the like, and polyvinyl alcohol adhesives are preferably used. After the adhesive layer is formed, the above-described polarized light-emitting panel can be produced by drying or heat treatment at an appropriate temperature.

The above-mentioned polarized light emitting panel may be 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. In the case of producing a layer having such various functionalities, a method of applying a material having various functionalities to the exposed surface of the transparent protective layer is more preferable, and various functional layers or films can be bonded to the exposed surface of the transparent protective layer via an adhesive or a bonding agent. Examples of the transparent protective layer include: and protective layers such as hard coat layers made of acrylic resins, silicone resins, and urethane resins. In addition, in order to further improve the transmittance, an antireflection layer may be provided on the exposed portion of the transparent protective layer. The anti-reflection layer can be formed by, for example, vapor depositing or sputtering a material such as silicon dioxide or titanium oxide onto the transparent protection layer, or thinly coating a fluorine-based material on the transparent protection layer.

(optical System)

The optical system of the present invention can be obtained by providing a light absorption filter having a photometric correction monomer transmittance of 45 to 100% in such a manner as to satisfy the following formula (1) or formula (2) in the above-obtained polarized light emitting element or polarized light emitting panel.

A _em-L-λmax ×F _em-L <0.6×A _fi-em-λmax <0.35 formula (1)

In the formula, A _em-L-λmax F is an absorbance at the maximum absorption wavelength of the axis on which the light absorption amount of the polarized light emitting element is the lowest _em-L Quantum yield of axis representing lowest light absorption amount of polarized light emitting element, A _fi-em-λmax The absorbance of the filter at the maximum emission wavelength of the polarized light-emitting element is represented.

0<TAF _em-L <0.7×TA _fi-em Formula (2)

In the formula, TA _fi-em TAF represents the value obtained by integrating the absorbances of the filters at the wavelengths in the range of light emission by the polarized light emitting element _em-L The value obtained by integrating the product of the absorbance at each wavelength on the axis on which the light absorption amount of the polarized light emitting element is the lowest and the quantum yield on the axis on which the light absorption amount of the polarized light emitting element is the lowest in the light absorption wavelength range of the polarized light emitting element is shown.

Here, the light absorption filter is a filter that absorbs light of a wavelength emitted by the polarized light emitting element, and light of a wavelength that emits light at a maximum on a weak axis of the polarized light emitting element can be effectively reduced by satisfying the above formula (1), so that an optical system having a high contrast of polarized light emission can be obtained.

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

A _em-L-λmax ×F _em-L <0.9×A _fi-em-λmax <0.35 formula (1-a)

More preferably, the light emission intensity (peak intensity of the spectrum of the weak axis) of the polarized light emitting element at a wavelength at which the light emission is the strongest in the weak axis is substantially eliminated by satisfying the following formula (1-b), and an optical system having high luminance, that is, an optical system having high contrast of the polarized light emission is obtained, and therefore, the polarized light emitting element is more preferably used.

A _em-L-λmax ×F _em-L <1.0×A _fi-em-λmax <0.35 formula (1-b)

Since the use of the light absorption filter can effectively reduce the wavelength of the polarized light emitting element that emits the maximum light on the weak axis, the absorbance of the filter (hereinafter, also referred to as "a") that absorbs light in the visible light region in which the polarized light emitting element exhibits the wavelength of the maximum light emission wavelength is absorbed _fi-em-λmax ") and 0.6 is more preferably 0.35 or less. When the amount is 0.35 or less, an optical system capable of providing polarized light emission with high luminance can be obtained. 0.6 XA _fi-em-λmax The value of (b) is more preferably 0.30 or less, still more preferably 0.22 or less, particularly preferably 0.18 or less, and still more preferably 0.15 or less. By setting to 0.30 or less, an optical system having high transmittance and capable of providing polarized light emission with high contrast can be obtained, which is more preferable.

Alternatively, the light emission amount of the polarized light emitting element on the weak axis can be reduced by satisfying the above expression (2), and an optical system having a high contrast of polarized light emission can be obtained.

It is more preferable that the light emission intensity of the polarized light emitting element on the weak axis be further reduced by satisfying the following formula (2-a).

0<TAF _em-L <0.85×TA _fi-em Formula (2-a)

More preferably, the light emission of the polarized light emitting element on the weak axis is substantially eliminated by satisfying the following formula (2-b), and an optical system having a high contrast of polarized light emission can be obtained.

0<TAF _em-L <1.0×TA _fi-em Formula (2-b)

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 the formula (1) or the formula (2), an optical system having a bright position and an extinction position with high contrast, which is high in transmittance and high in polarization, can be obtained. Since the light emission line of the polarized light emitting element at the weak light emission position can be suppressed by the formula (1) and the light amount of the polarized light emitting element at the weak light emission position can be suppressed by the formula (2), the formula (1) and the formula (2) are respectively suitable conditions for obtaining an optical system having a bright position and an extinction position which have high transmittance and high polarization, that is, high contrast. More preferably, at least formula (2) is satisfied, and still more preferably, formula (1) and formula (2) are satisfied simultaneously.

(optical Filter absorbing light of visible light)

By adjusting the transmittance of the monomer to 45 to 100% for photometric correction of the filter used in the present invention, an optical system having high transparency can be obtained. When the polarized light emitting element used in the present invention has all or a part of the absorption wavelength of light in the ultraviolet region to the near ultraviolet visible region (specifically, 300 to 430nm), for example, the light has high transparency because the absorption of light at 400 to 700nm is significantly low. Therefore, an optical system having higher transparency can be obtained by making the photometrically corrected monomer transmittance of the aforementioned optical filter to be 50 to 99.9%, more preferably 60 to 99.9%, still more preferably 70 to 99.9%, and yet more preferably 80 to 99.9%.

In addition, when the filter is provided, the transmittance at each wavelength of the polarized light emitting element, particularly the transmittance at each wavelength in a wavelength band in which light is emitted is more preferably 45 to 100%, and thus an optical system having high contrast and high transparency can be more effectively obtained, which is more preferable. A more preferable mode of the present application can be achieved by the transmittance of the aforementioned filter in the emission wavelength of the polarized light emitting element being 50 to 99.9%, and more preferably 60 to 99.9%, more preferably 70 to 99.9%, and still more preferably 80 to 99.9%. By providing such a filter on the side where a person visually recognizes, it is more effective for the person visually recognizing to provide a high contrast in the optical system of the present application, and therefore, such a filter is preferable.

The visible light absorption filter used in the present invention is preferably a polarizing element or a polarizing plate. The polarizing plate means that a transparent protective film is provided on a polarizer (in other words, the polarizing plate includes a polarizer and a transparent protective film), and the transparent protective film is preferably used so as not to hinder the optical characteristics of the polarizer and to prevent light absorption in the ultraviolet region. The polarizing element is not particularly limited as long as it has an axial absorption anisotropy with respect to light in the visible light region, that is, has a polarizing function, and is preferably used because it can provide an optical system having a high brightness or a high contrast equal to or higher than that of the optical filter (the polarizing element) by using a polarizing element satisfying the formula (1) or the formula (2) among the monomer transmittance or the monomer absorbance.

Examples of the polarizing plate using the polarizing element include: iodine-based polarizing plates, dye-based polarizing plates capable of controlling only a specific wavelength by polarization, polarizing plates using polyenes, wire grid-type polarizing plates, reflection-type polarizing plates, and the like. The above-described polarizing element has a polarizing property for light in a part or all of a wavelength region of 400 to 700 nm. Examples of the iodine-based polarizing plate include Japanese patent application laid-open Nos. 2001-290029 and 2010-072548; examples of the dye-based polarizing plate include Japanese patent laid-open Nos. 2001-033627, 2004-251962, and 7; examples of dye-based polarizing plates that can control only a specific wavelength by polarization include jp 2007 a-084803, jp 2007 a-238888, WO2012-165223, and patent document 8; examples of the polarizing plate using polyene include those described in Japanese patent application publication Nos. 2005-527847 and 2005-517974; examples of the wire grid type polarizing plate include Japanese patent publication No. 2003-519818 and Japanese patent publication No. 2003-502708. Examples of the reflective polarizing plate include U.S. Pat. Nos. 3610729, WO95/17303, WO95/17692, WO95/17699, WO96/19347, WO99/36262, WO2005/0888363, Japanese patent laid-open No. 2007-298634, and WO2011/074701, and examples of the product include DBEF from 3M company. The polarizing element is more preferably a dye-based polarizing plate or a polyene-based polarizing plate because the monomer has a transmittance satisfying the formula (1) or the formula (2) or the formula (3) or the formula (4) and has high long-term storage stability and durability stable even under severe conditions, and particularly preferably a dye-based polarizing plate obtained by stretching a substrate such as a polyvinyl alcohol film in an aqueous boric acid solution while containing a dichroic dye in the substrate. Further, the dichroic dye is exemplified by the dichroic dye described in non-patent document 1.

The polarizing element preferably has a function as a polarizing element when the ratio of the absorption amount of the axis having the strongest absorption to the absorption amount of the axis having the lowest absorption is 3 or more, that is, the dichroic ratio is 3 or more. More preferably 10 or more, still more preferably 20 or more, particularly preferably 35 or more, still more particularly preferably 40 or more. The polarization degree of the polarizing element may be 30% or more, more preferably 40% or more, still more preferably 60% or more, still more preferably 80% or more, and particularly preferably 90% or more.

In the case of using a polarizing element or a polarizing plate using the polarizing element as the visible light absorption filter used in the present invention, it is preferable that the axis of the polarized light emitting element having the weakest maximum light emission amount be parallel to the axis of the polarized light emitting element having the highest absorbance. The angle of the state in which the axis of the polarized light emitting element having the weakest amount of light emission and the axis of the polarized light emitting element having the highest absorbance are parallel to each other is not necessarily completely coincident with each other, and may be a parallel state in which display is facilitated. It is particularly preferable that the axis of the polarized light emitting element with the weakest amount of light emission be completely parallel to the axis of the polarized light emitting element with the highest absorbance, because the optical system of the present invention can provide the highest brightness and high contrast. Although it is substantially possible to achieve a state in which the axis of the polarized light emitting element, which is the weakest in the amount of light emission, is parallel to the axis of the polarized light element, which is the highest in the absorbance, it is preferably within 10 °, more preferably within 5 °, even more preferably within 2 °, and particularly preferably within 1 ° with respect to the completely parallel axis.

The filter is preferably a polarizing element, and satisfies the following formula (3) because an optical system having a high contrast of polarized light emission can be obtained.

A _em-L-λmax ×F _em-L <0.6×A _{Pol-Kz-em-L-λmax} <0.7 type (3)

In the formula, A _em-L-λmax F is an absorbance at the maximum absorption wavelength of the axis on which the light absorption amount of the polarized light emitting element is the lowest _em-L Quantum yield of axis representing lowest light absorption amount of polarized light emitting element, A _{Pol-Kz-em-L-λmax} The absorbance of the polarizing element having the wavelength of maximum light emission on the axis on which the amount of light emitted by the polarizing light-emitting element is the weakest is indicated on the highest absorption axis.

By satisfying the above formula (3), an optical system having a high transmittance, a high luminance at a light-emitting position, and a significantly small emission luminance at an extinction position, particularly, a light emission wavelength at a maximum of the extinction position, that is, a high-contrast optical system can be obtained as compared with the case of using a visible light absorption filter which is not a polarizing element.

It is more preferable that an optical system having high luminance and low light emission luminance at an extinction position, that is, an optical system having high contrast can be obtained by satisfying the following formula (3-a) with the filter. More preferably, the filter satisfies the following formula (3-b).

A _em-L-λmax ×F _em-L <0.8×A _{Pol-Kz-em-L-λmax} <0.7 formula (3-a)

A _em-L-λmax ×F _em-L <1.0×A _{Pol-Kz-em-L-λmax} <0.7 formula (3-b)

In the above formula (3), 0.6 XA _{Pol-Kz-em-L-λmax} More preferably less than 0.6, still more preferably less than 0.5, still more preferably less than 0.4, and particularly preferably less than 0.3. By the foregoing more preferable aspect, an optical system higher in transmittance, higher in luminance, and/or less in light emission luminance at the extinction position, that is, an optical system higher in contrast and/or higher in transmittance can be obtained.

In a more preferred aspect, when the filter is a polarizing element, an optical system in which the amount of light emission of the polarized light-emitting element is reduced in the weak axis and the contrast of the polarized light emission is high as compared with the case where the filter is a non-polarizing element can be obtained by satisfying the following formula (4).

0<TAF _em-L <0.7×TA _pol-Kz-em Formula (4)

In the formula, TA _pol-Kz-em The TAF is a value obtained by integrating the absorbances of the polarizer at the wavelengths of the highest absorption axis in the wavelength range in which the polarized light emitting element emits light _em-L The expression is the same as in formula (2).

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

0<TAF _em-L <0.8×TA _pol-Kz-em Formula (4-a)

More preferably, the following formula (4-b) is satisfied, and still more preferably, the following formula (4-c) is satisfied.

0<TAF _em-L <0.9×TA _pol-Kz-em Formula (4-b)

0<TAF _em-L <1.0×TA _pol-Kz-em Formula (4-c)

In the visible light absorption filter used in the present invention, the visible light absorption filter is produced by mixing a visible light absorption filter according to JIS Z8781-4: 2013 the obtained monomer had a hue of-5<a ^＊ <+3 and b ^＊ <. + -. 3, a neutral color optical system can be obtained, and is therefore more preferable. In particular, when the polarized light emitting element has a neutral color or a high transmittance, the filter is colored in the neutral color, i.e., a ^＊ And b ^＊ Suitably all have a value close to zero. When the filter is a polarizing element, the filter may be a single body having a hue of-5<a ^＊ <+3 and. b ^＊ <Plus or minus 3 to obtain the same effect. a is ^＊ The value of (B) is more preferably-3 to 2, still more preferably-2 to 1. b ^＊ The value of (B) is more preferably-2 to 2, still more preferably-1 to 1.

In the optical system of the present invention, the polarized light emitting element and the filter may be separately disposed, and the polarized light emitting element and the filter are laminated, whereby an optical system having higher luminance and high transmittance can be provided, which is preferable. In general, the optical member has a reduced light transmittance due to the reflection at the interface when light is incident on the interface. Therefore, in the optical system of the present invention, in order to obtain an optical system with high luminance and high transmittance, it is important to reduce the interface and reduce the interface reflection on the optical path of the optical system. Therefore, the stacked polarized light emitting device and the polarized light device are a preferred configuration.

In addition, according to an aspect of the present invention, a phase control medium may be provided in the optical system. Examples of the medium having a phase include a retardation plate (also referred to as a wavelength plate or a retardation film), a liquid crystal panel (liquid crystal cell) in which liquid crystal is electrically driven and controlled, and the like. In particular, since a liquid crystal display device can be obtained by using a liquid crystal panel (liquid crystal cell) capable of electrically controlling a phase as a medium for controlling a phase, it is a more preferred aspect of the present invention. When the optical system of the present invention is used, a self-luminous liquid crystal display can be manufactured because the polarized light emitting element emits light, and a display device having a very high transmittance and a high contrast can be obtained because a high transmittance and a high contrast liquid crystal display can be obtained. In general, the liquid crystal display uses 2 polarizing plates, but the parallel transmittance is 25 to 35% when 2 polarizing plates are used. The liquid crystal display using a well-known polarizing plate having a parallel transmittance of 25 to 35% is low in quality as a see-through display because of low transmittance, and in addition, a backlight must be provided because it is not self-luminous, but transparency cannot be obtained because the backlight unit uses CCFL or LED. In contrast, the polarized light emitting element used in the optical system of the present invention is transparent and emits light, and therefore can be used as a transparent and self-luminous liquid crystal display device.

In addition, by using a medium having a phase, when polarized light is represented as a light wave having properties of a particle and a wave, the phase of the wave can be controlled. When focusing on polarization, for example, the wavelength plate is an optical functional element that gives a predetermined phase difference to linearly polarized light, and the polarization can be provided with a different phase for light of a specific axis in other axes (for example, 90 °). That is, by providing a wavelength plate on the optical path of one polarized light, it is possible to convert the polarized light into the polarized light of the opposite axis, and to newly impart circular polarized light, elliptical polarized light, or the like. The wavelength plate is an element that can change the polarization state of incident light by imparting a phase difference to 2 orthogonal polarization components using an oriented birefringent material (e.g., an oriented film) or the like. Specific uses of the wavelength plate are, for example: when the wavelength of a specific light is λ, the slow axis of the retardation plate of λ/2 is set to 45 ° with respect to the polarization axis, and by this means, the linearly polarized light that has entered the wavelength plate (retardation plate) can be rotated by 90 ° and emitted as polarized light having a polarization axis in a direction orthogonal (90 °) to the polarization axis that has entered. When the axis angle is set to 45 ° with respect to the axis of the objective polarized light, the retardation plate functions to some extent even if the retardation plate is shifted by about ± 10 °, but the retardation plate is preferably within a range of ± 5 °, more preferably within a range of ± 3 °, more preferably within a range of ± 2 °, and particularly preferably within a range of ± 1 °. When the slow axis of the retardation plate of λ/4 is set at 45 ° with respect to the axis of polarization, the linearly polarized light incident on the wavelength plate (retardation plate) can be emitted as circularly polarized light.

The optical system of the present invention thus manufactured exhibits polarized light emission in the visible light region and high transmittance, that is, a high-brightness and high-contrast optical system. The optical system of the present invention exhibits excellent durability against heat, humidity, light, and the like, and thus can maintain its performance even in a severe environment, and has higher durability than a known iodine-based polarizing plate. Therefore, the optical system of the present invention can be effectively used not only for lenses, glasses, and liquid crystal displays that require high transparency in the visible light region and high durability in severe environments, but also for various display devices such as televisions, wearable terminals, desktop terminals, smart phones, screens for vehicles, see-through displays, electronic signs used outdoors or indoors, smart windows, and the like, and for high-efficiency polarized backlights for liquid crystal display orientations, and for polarized light sources that can emit light with high efficiency.

(display device)

In the present invention, when a specific polarized light-emitting dye is used, a polarized light-emitting action is exhibited by irradiation with light in the ultraviolet to near-ultraviolet visible light region (specifically, irradiation with light of 300 to 430nm), and the effect can be utilized to display the result. The display device of the present invention has a high transmittance in the visible light region, and thus the decrease in transmittance in the visible light region can be significantly reduced as in the known polarizing plate. Further, since the environment and the image on the back surface can be viewed through the display device from the viewing side even when characters, images, and the like are displayed, a display which is transparent and visible on the back surface at the same time of display, that is, a display which is transparent but can display characters and the like can be obtained. Moreover, the display device of the present invention is effectively applied as a transparent liquid crystal display without light loss, especially a see-through display.

In addition, the display device of the present invention can manufacture, for example, a liquid crystal display which displays a polarized light emission effect by irradiation of ultraviolet light and utilizes the polarized light emission. Therefore, a liquid crystal display using invisible light using ultraviolet light can be realized instead of a normal liquid crystal display using visible light. In other words, it is possible to produce a self-light-emitting liquid crystal display that can display characters, images, and the like to be displayed even in a dark space without light if the space can be irradiated with ultraviolet light.

The liquid crystal cell used in the liquid crystal display for vehicle or outdoor display using the optical system of the present invention is not limited to TN liquid crystal, STN liquid crystal, VA liquid crystal, IPS liquid crystal, and the like, for example, and the liquid crystal display can be used in all liquid crystal display modes.

The optical system of the present invention is excellent in polarized light emission performance, and can suppress discoloration and deterioration in polarized light emission performance even in a high-temperature and high-humidity state inside or outside a vehicle. Therefore, it is useful to improve long-term reliability of a liquid crystal display for vehicle or outdoor display.

[ examples ]

The present invention will be described in more detail below with reference to examples, but these are illustrative examples and are not intended to limit the present invention. The following "%" and "part(s)" are based on mass unless otherwise specified. In the respective structural formulae of the compounds used in the respective examples and comparative examples, the acidic functional group such as a sulfo group is described as a free acid.

[ evaluation method ]

Each of the polarized light emitting elements or polarized light emitting panels obtained in the following examples and comparative examples was evaluated as a measurement sample in the following manner.

[ measurement of penetration Rate ]

The transmittances and absorbances of the polarized light emitting element, the polarized light emitting panel, the polarizing element, the polarizing plate, and the optical system were evaluated using a spectrophotometer ("U-4100" manufactured by Hitachi HIGH Technologies Co., Ltd.). Each of the polarized light emitting elements (measurement samples) prepared in examples and comparative examples was irradiated with light having 100% of polarization in a wavelength region of 220nm to 2600nm (hereinafter, also referred to as "absolute polarization") to form a Gram Thomson (Gram Thomson) polarizer, and the transmittance of light of each wavelength was measured when each measurement sample was irradiated with absolute polarization.

[ photometric-corrected monomer transmittance Ys, photometric-corrected orthogonal transmittance Yc ]

In the polarized light emitting element, the polarized light emitting panel, the polarizing element, the polarizing plate, or the optical system, Ky is a transmittance of light measured when incident polarized light having an axis orthogonal to an axis on which absolute polarization is irradiated and which exhibits the highest absorption of light by the orientation of the dye, and Kz is a transmittance of light measured when incident polarized light having an axis parallel to the axis on which absolute polarization is irradiated and which exhibits the highest absorption of light by the orientation of the dye is incident. In addition, Ky in the polarized light emitting element shows the transmittance of light on the axis where light is the weakest, and Kz in the polarized light emitting element shows the transmittance of light on the axis where light is the strongest. The photometric corrected monomer transmittance Ys and photometric corrected orthogonal transmittance Yc of each measurement sample are obtained by substituting the above Ky and Kz obtained for each predetermined wavelength interval d λ (here, 5nm) in the wavelength region of 380 to 780nm in the visible light region into formula (I) to calculate the monomer transmittance Ts at each wavelength, substituting the monomer transmittance Tc at each wavelength into formula (II), and calculating the monomer transmittance Tc at each wavelength in accordance with JIS Z8722: 2009 to correct for luminous transmittance. Specifically, the monomer transmittance Ts for each wavelength is substituted into the following formula (III) to calculate the photometric corrected monomer transmittance Ys, and the orthogonal transmittance Tc for each wavelength is substituted into the following formula (IV) to calculate the photometric corrected orthogonal transmittance Yc. In the following formula (III) or (IV), P λ represents the spectral distribution of the standard light (C light source), and y λ represents the 2-dimensional visual field color matching function. The photometric corrected cell transmittance Ys represents the transmittance when viewed as a cell, and the photometric corrected orthogonal transmittance Yc represents the transmittance when viewed orthogonally with respect to the 2 measurement sample pieces.

Ts＝(Ky+Kz)/2 (I)

Tc＝(Ky×Kz)/100 (II)

(color a) ^＊ Value and b ^＊ Value)

For each measurement sample, the reaction conditions were determined in accordance with JIS Z8781-4: 2013, determining the chromaticity a of the monomer at the time of the transmittance Ts measurement ^＊ Value and b ^＊ The value is obtained. The transmittance at each wavelength was measured by using the spectrophotometer described above, and the light source used a C2 ° field of view. a is ^＊ -s and b ^＊ S corresponds to the chromaticity a of the monomer at the time of measurement of the transmittance Ts ^＊ Value and b ^＊ The value is obtained.

(Absorbance)

The absorbance (Abs) at each wavelength on each axis of each measurement sample is obtained using Tr obtained by substituting Ky and Kz described above into the following formula (V).

Abs＝-Log(Tr) (V)

(Quantum yield of polarized light emitting element)

The quantum yield on each axis of the polarized light emitting element was measured using a value obtained by FP-8500 manufactured by japan spectrographic corporation. Specifically, when the quantum yield of the polarized light emitting element is measured by FP-8500 manufactured by japan spectrographic company, the quantum yield obtained by irradiating an axis polarized light showing the highest absorption of light by the orientation of the polarized light emitting pigment and the quantum yield obtained by irradiating an axis polarized light showing the lowest absorption of light by the orientation of the polarized light emitting pigment are measured as the quantum yield of the polarized light emitting element of the present invention so that the polarized light can be incident on the polarized light emitting element.

(emission intensity of each wavelength of polarized light emitting element, and degree of polarization (DOP) of emitted light)

The emission intensity of each wavelength of the polarized light emitting element and the degree of polarization (DOP) of emitted light were measured by the Stokes parameter method. Specifically, a value measured by a spectroscopic polarimeter (Poxi-Spectra, manufactured by Tokyo Instruments Co., Ltd.) was used. All the types (states) of polarized light emission of the polarized light emitting elements and the polarized light emitting panels used in the following examples and comparative examples, which were confirmed by a spectropolarimeter Poxi-Spectra manufactured by Tokyo Instruments, were linearly polarized.

(preparation of polarized light-emitting element A)

A polyvinyl alcohol film (VF-PS #7500 manufactured by KURAAY corporation) having a thickness of 75 μm was immersed in hot water at 40 ℃ for 3 minutes to swell the film. The membrane obtained by swelling was immersed in an aqueous solution at 45 ℃ containing 0.8 parts by weight of 4, 4' -bis- (sulfostyryl) biphenyl disodium salt described in formula (B-1) (Tinopal NFW Liquid, manufactured by BASF corporation), 1.0 part by weight of mirabilite, and 1500 parts by weight of water for 4 minutes. After the dipping, the obtained film was stretched in a 3% aqueous solution of boric acid at 50 ℃ for 5 minutes to have a length 5 times as long. The film obtained by stretching was washed with water at normal temperature for 20 seconds while maintaining the original stretched state, and then dried at 70 ℃ for 9 minutes to obtain a polarized light emitting element a. The order parameter of the polarized light-emitting element a calculated from the above formula (5) was 0.91, and the wavelength at which the absorption maximum was 375 nm. When the polarized light emitting element a was irradiated with ultraviolet rays and light emission thereof was confirmed through a general polarizing plate (SKN-18243P manufactured by POLATECHNO), blue polarized light emission was emitted in the direction of the elongation axis during the processing of the polarized light emitting element, while the polarized light emission was significantly low in the direction orthogonal to the elongation axis. In other words, the polarized light emitting element is an element that emits linearly polarized light.

(preparation of polarized light plate A Using polarized light emitting element A)

A triacetyl cellulose FILM (ZRD-60, manufactured by Fuji FILM Co.) containing no ultraviolet absorber was treated with 1.5 equivalents of an aqueous solution of sodium hydroxide at 35 ℃ for 10 minutes, washed with water, and then dried at 70 ℃ for 10 minutes. A triacetyl cellulose film (hereinafter referred to as TAC) obtained by alkali treatment was laminated on both surfaces of the polarized light emitting element a via an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, japan), and dried at 70 ℃ for 10 minutes to prepare a polarized light emitting panel a configured as TAC/polarized light emitting element a/TAC. The obtained polarized light-emitting panel a has the characteristics of the polarized light-emitting element a without impairing the optical characteristics of the obtained polarized light-emitting element a.

(preparation of polarized light emitting element B and polarized light emitting Panel B)

A polarized light-emitting device B and a polarized light-emitting panel B were produced in the same manner except that 0.05 part by weight of the aqueous solution of the compound represented by the formula (B-1) was used instead of 0.8 part by weight of the aqueous solution of the compound represented by the formula (B-1) in producing the polarized light-emitting device A and the polarized light-emitting panel A. The order parameter of the polarized light-emitting element B calculated by the above formula (5) was 0.84, and the maximum wavelength of absorption was 380 nm. When the present polarized light emitting panel B was irradiated with ultraviolet rays and light emission thereof was confirmed through a general polarizing plate (SKN-18243P manufactured by polatehnol corporation), blue polarized light emission was emitted in the direction of the extension axis during the processing of the polarized light emitting element, while the polarized light emission was significantly low in the direction orthogonal to the extension axis. In other words, the polarized light emitting element is an element that emits linearly polarized light.

(Synthesis example 1)

Commercially available 4-diamino-stilbene-2, 2' -disulfonic acid (35.2 parts) was added to water (300 parts) and stirred, and then the pH was adjusted to 0.5 using 35% hydrochloric acid. To the resulting solution, 10.9 parts of a 40% sodium nitrite aqueous solution was added, followed by stirring at 10 ℃ for 1 hour, followed by addition of 34.4 parts of 6-aminonaphthalene-2-sulfonic acid and adjustment to pH4.0 with a 15% sodium carbonate aqueous solution, followed by stirring for 4 hours. To the obtained reaction solution, 60 parts of sodium chloride was added, and the precipitated solid was separated by filtration, washed with 100 parts of acetone, and dried to obtain 62.3 parts of a compound represented by the following formula (S-7 p).

62.3 parts of the compound of the formula (S-7p) obtained above was added to 300 parts of water and stirred, and then a 25% aqueous solution of sodium hydroxide was used to obtain a pH of 10.0. To the resulting solution were added 20 parts of 28% aqueous ammonia and 9.0 parts of copper sulfate pentahydrate, followed by stirring at 90 ℃ for 2 hours. To the obtained reaction solution, 25 parts of sodium chloride was added, and the precipitated solid was separated by filtration and washed with 100 parts of acetone to obtain 40.0 parts of a wet cake, which was dried by a hot air dryer at 80 ℃ to obtain 20.0 parts of a polarized luminescent dye represented by the formula (S-7).

(preparation of polarized light emitting element C and polarized light emitting plate C)

A polarized light-emitting element C and a polarized light-emitting panel C were produced in the same manner except that 0.1 part by weight of a polarized light-emitting dye represented by the formula (S-7) was used as the polarized light-emitting dye instead of 0.8 part by weight of the aqueous solution of the compound represented by the formula (B-1) in the production of the polarized light-emitting element A and the polarized light-emitting panel A. The order parameter of the polarized light-emitting element C calculated by the above formula (5) was 0.84, and the wavelength of absorption maximum was 400 nm. When the present polarized light emitting panel C was irradiated with ultraviolet rays and light emission thereof was confirmed through a general polarizing plate (SKN-18243P manufactured by polatehnol corporation), blue polarized light emission was emitted in the direction of the extension axis during the processing of the polarized light emitting element, while the polarized light emission was significantly low in the direction orthogonal to the extension axis. In other words, the polarized light emitting element C is an element that emits linearly polarized light.

Ky and Kz of each wavelength of the polarized light emitting panels A to C obtained by measuring each 5nm with a spectrophotometer (manufactured by Hitachi Technologies Co., Ltd. "U-4100") are shown in FIG. 1; fig. 2 shows emission intensity ratios of the respective wavelengths of the polarized light-emitting panels a to C measured by a spectroscopic polarimeter (a spectroscopic polarimeter Poxi-Spectra manufactured by tokyo Instruments) with the intensity of the emission wavelength showing the maximum value set to 1; fig. 3 shows the degree of polarization (DOP) in which the emission intensity ratio of each wavelength is 0.05 or more, when the intensity of the emission wavelength at which the polarized light emitting panels a to C exhibit the maximum value among the emitted light is 1.

In table 1, it is shown that: the photometric correction monomer transmittance (Ys- _em ) Maximum absorption wavelength (. lamda.max-A) _em ) And absorbance (A) at a wavelength at which the light absorption amount of the polarized light emitting panel showing the maximum absorption wavelength is maximum absorption on the axis of maximum absorption _em-H-λmax ) And a value (TA) obtained by integrating absorbance in a light absorption wavelength range at each wavelength on an axis that maximizes the light absorption amount of the polarizing light-emitting panel _em-H ) Quantum yield (F) of axis having highest light absorption of polarized light emitting panel _em-H ) And absorbance (A) of a wavelength having a maximum absorption on the axis where the light absorption amount of the polarized light emitting panel having the maximum absorption wavelength is the lowest _em-L-λmax ) And a value (TA) obtained by integrating absorbance in a light absorption wavelength range for each wavelength on an axis on which the light absorption amount of the polarizing light-emitting panel is the lowest _em-L ) Quantum yield (F) of axis with lowest light absorption of polarized light emitting panel _em-L ) Maximum luminescence wavelength (lambda max-EM) _em ) And a Range of emission wavelengths (Range-EM) _em )。

In table 2, the following are shown: the light absorption of the obtained polarized light emitting panel was measured every 5nm and was determined as the absorbance (A) of the wavelength of maximum absorption of the axis having the highest light absorption _em-H-λmax ) Quantum yield (F) of the axis having the highest light absorption amount with the polarized light emitting panel _em-H ) The product of the absorbance of each wavelength of the axis having the highest light absorption amount of the polarized light emitting panel and the light absorption amount of the polarized light emitting panel is the highestHigh axial quantum yield value (TAF) obtained by integrating the product of the quantum yields in the light absorption wavelength range of the polarized light-emitting panel _em-H ) And absorbance (A) of a wavelength showing that the light absorption amount of the polarized light emitting panel is maximum absorption of the axis of the lowest light absorption _em-L-λmax ) Quantum yield (F) with axis having lowest light absorption amount of polarized light emitting panel _em-L ) A value obtained by integrating the product of absorbance of each wavelength of the axis on which the light absorption amount of the polarized light emitting panel is the lowest and the product of the quantum yield of the axis on which the light absorption amount of the polarized light emitting panel is the lowest in the light absorption wavelength range of the polarized light emitting panel (TAF) _em-L )。

[ Table 1]

[ Table 2]

As is clear from the results shown in fig. 1, table 1, and table 2, the polarized light emitting panel a absorbs light of about 425nm or less, the polarized light emitting panel B absorbs light of about 405nm or less, and the polarized light emitting panel C absorbs light of 440nm or less, and has optical axis absorption anisotropy, that is, a polarization function. As is clear from the results shown in fig. 2 and 3, the polarized light-emitting panels a and B emit light at 400 to 570nm, the polarized light-emitting panels C emit light at 430 to 600nm, and the light emitted from the respective polarized light-emitting panels has a high degree of polarization (DOP).

(preparation of polarizing element A and polarizing plate A)

According to the method of example 1 of patent document 7, a polyvinyl alcohol film (VF-PS #7500 manufactured by KURARAAY corporation) having a thickness of 75 μm was immersed in 45 ℃ warm water for 2 minutes, and swelling treatment was applied to set the draw ratio to 1.30 times. In the dyeing step, the film subjected to swelling treatment was immersed in a 45 ℃ solution containing 2000 parts by weight of water, 2.0 parts by weight of thenardite, 0.34 parts by weight of an azo compound described in synthetic example 1 of international publication No. WO2012/165223, 0.027 parts by weight of an azo compound described in synthetic 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 390.16 parts by weight of c.i. direct orange for 1 minute and 00 seconds to contain the azo compound in the film. The obtained membrane was immersed in an aqueous solution containing 20g/l of boric acid (Societa Chimica Lardeello.p.a.) at 40 ℃ for 1 minute. The obtained film was stretched 5.0 times while conducting a stretching treatment in an aqueous solution at 50 ℃ containing 30.0g/l of boric acid for 5 minutes. The resulting film was kept in a taut state while being treated with water at 25 ℃ for 20 seconds. The obtained film was dried at 70 ℃ for 9 minutes to obtain a type of polarizing element a of a visible light absorption filter. A triacetyl cellulose FILM (ZRD-60, manufactured by Fuji FILM Co.) containing no ultraviolet absorber was treated with 1.5 equivalents of an aqueous solution of sodium hydroxide at 35 ℃ for 10 minutes, washed with water, and then dried at 70 ℃ for 10 minutes. The alkali-treated triacetyl cellulose film was laminated on both sides of the polarizing element a via an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, japan), dried at 70 ℃ for 10 minutes, and provided with an antireflection layer (AR layer) on the surface to form a polarizing plate a in one of forms of visible light absorption filters configured as an 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.

(preparation of polarizing element B and polarizing plate B)

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

(preparation of polarizing element C and polarizing plate C)

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

< preparation of polarizing element D and polarizing plate D >

A polarizer D and a polarizing plate D, which are one of the forms of the visible light absorption filter used in the present application, were produced in the same manner except that a polyvinyl alcohol film (VF-PS #7500 manufactured by KURARAY corporation) having a thickness of 75 μm in the production of polarizer a was immersed in warm water at 40 ℃ for 3 minutes to swell the film, and the film obtained by swelling was immersed in an aqueous solution at 45 ℃ containing 0.04 parts by weight of an azo compound, 1.0 parts by weight of mirabilite, and 1500 parts by weight of water described in example 1 of patent document 8 for 4 minutes. The obtained polarizing plate D has the characteristics of the polarizing element D without impairing the optical characteristics of the obtained polarizing element D.

< preparation of polarizing element E and polarizing plate E >

A polarizer E and a polarizing plate E, which are one of the forms of a visible light absorption filter, were produced in the same manner except that a polyvinyl alcohol film (VF-PS #7500 manufactured by KURARARAAY corporation) having a thickness of 75 μm in the production of the polarizer A was immersed in warm water at 40 ℃ for 3 minutes to swell the film, and the film obtained by swelling was immersed in an aqueous solution at 45 ℃ containing 0.03 parts by weight of an azo compound, 1.0 parts by weight of Glauber's salt, and 1500 parts by weight of water as described in Synthesis example 1 of Japanese patent application laid-open No. 2003-215338 for 4 minutes. The obtained polarizing plate E has the characteristics of the polarizing element E without impairing the optical characteristics of the obtained polarizing element E.

A visible light absorption filter F, in which both surfaces of the laminate were bonded/joined, was produced by a method having a transmittance of about 70% at each wavelength in the visible light region.

A mixture of 0.095 parts of KAYASET BLACK A-N and 0.0048 parts of KAYASET BLUE A-D (manufactured by JAPONIC CHEMICAL Co., Ltd.) was mixed with 100 parts of the resin solid content of the pressure-sensitive adhesive PTR-3000 manufactured by JAPONIC CHEMICAL Co., Ltd., and methyl ethyl ketone was added to the resulting mixture so that the solid content of the mixture was 17 parts with respect to 100 parts of the prepared composition, followed by mixing for 1 hour to obtain a pressure-sensitive adhesive composition for an optical filter. The obtained adhesive composition for an optical filter was sandwiched between 2 release films (polyethylene terephthalate films) by using a coater, and formed into a sheet shape having a thickness of 25 μm, thereby producing an optical filter F.

As the visible light absorption filter G having a transmittance of 80% at each wavelength in the visible light region, a Neutral density filter ND-0.1 (manufactured by fuji FILM corporation) was used.

The visible light absorption filter H for which the laminate was adhesively bonded on both sides and which had a transmittance of about 90% in the visible light region at each wavelength was produced by the following method.

A compounded composition was obtained by mixing and stirring 0.0092 parts of KAYASET BLACK A-N (manufactured by Nippon chemical Co., Ltd.) and 0.001 parts of KAYASET BLUE A-D (manufactured by Nippon chemical Co., Ltd.) with respect to 100 parts of the solid resin content in adhesive PTR-3000 manufactured by Nippon chemical Co., Ltd., and methyl ethyl ketone was added to the mixed composition so that the solid content was 17 parts with respect to 100 parts of the compounded composition obtained and the mixture was mixed for 1 hour to obtain an adhesive composition for an optical filter. The obtained adhesive composition for an optical filter was sandwiched between 2 release films (polyethylene terephthalate films) by using a coater and formed into a sheet having a thickness of 25 μm, thereby producing an optical filter H.

SKN-18243P manufactured by POLATE CHNO, a general iodine type polarizing plate having a transmittance of 43% (hereinafter, referred to as a polarizing plate I) was used as a visible light absorption filter used in the comparative example.

In FIG. 4, Ky and Kz per 10nm of a polarizing plate A, a polarizing plate B, a polarizing plate C, a polarizing plate D and a polarizing plate E measured per 5nm are shown, and in FIG. 5, transmittance per 20nm measured per 5nm of a filter F sandwiched by TAC films, a filter H sandwiched by TAC films and a filter G not sandwiched by TAC films are shown.

In Table 3, the following are shown: the transmittance of monomer for light correction (Ys- _fi ) The optical intensity correction of the orthogonal transmittance (Yc- _fi ) Color of monomer (a) ^＊ -s and b ^＊ -s), absorbance of the monomer at 435nm (A) _fi-em-435 ) Absorbance of the monomer at 465nm (A) _fi-em-465 ) And a value (T) obtained by integrating the absorbances of the monomers at respective wavelengths of 400 to 570nmA _fi-em400-570 ) And a value (TA) obtained by integrating the absorbance of the monomer at each wavelength of 430 to 600nm _fi-em430-600 ) 435nm absorbance on the axis of strongest absorption (A) _{pol-Kz-em-L-435} ) Absorbance at 465nm on the axis with the strongest absorption (A) _{pol-Kz-em-L-465} ) And the value obtained by integrating the absorbances at the wavelengths of the axes having the strongest absorption at 400 to 570nm (TA) _{pol-Kz-em-400-570} ) And the value obtained by integrating the absorbances at the respective wavelengths of the axis having the strongest absorption at 430 to 600nm (TA) _{pol-Kz-em-430-600} )。

[ Table 3]

In Table 4 are shown: the transmittance of the monomer for photometric correction (Ys- _fi ) The hue (a) of the monomer ^＊ -s and b ^＊ -s), absorbance at 435nm (A) _fi-em-435 ) Absorbance at 465nm (A) _fi-em-465 ) And a value obtained by integrating the absorbances of the filters at respective wavelengths of 400 to 570nm (TA) _fi-em _400-570 ) And a value (TA) obtained by integrating absorbances at respective wavelengths of the filter in the range of 430 to 600nm _fi-em _430-600 ). In addition, since the filter F, the filter G, and the filter H are not polarizing plates, the cross transmittance (Yc- _fi )。

[ Table 4]

As is clear from fig. 4 and 5, the visible light absorption filter used in the present invention has a function of absorbing light at the wavelength of light emitted by the polarized light-emitting panels a to C. In addition, the polarizing plates a to E have axial absorption anisotropy of light, that is, polarization characteristics, for wavelengths at which light is emitted in the polarized light emitting panels a to C. When the polarizing plates a to E have a photometric-corrected cell transmittance substantially equal to that of the filter F having a transmittance of 70%, the filter G having a transmittance of 80%, and the filter H having a transmittance of 90%, the absorbance of the axis showing the strongest absorption is high.

As can be seen from tables 3 and 4, a is the same for the polarizers A to C and the filters F to H ^＊ -s、b ^＊ The highest absolute value of-s is also within 2.072, in particular, a of the polarizers A to C ^＊ -s、b ^＊ An absolute value of-s of 1 or less, and a neutral hue.

(preparation of polarizing plate for ultraviolet region J)

A polyvinyl alcohol film (VF-PS #7500 manufactured by KURARAAY) having a thickness of 75 μm was immersed in warm water at 40 ℃ for 3 minutes to swell the film. The swollen film was immersed in an aqueous solution of c.i. direct yellow 280.8 parts, mirabilite 1.0 part, and water 1500 parts at 45 ℃ for 5 minutes to contain the solution. The resulting film was immersed in a 3% aqueous boric acid solution at 50 ℃ for 5 minutes while being stretched 5 times. The stretched film was kept in an original stretched state, washed with water at normal temperature for 20 seconds, and dried at 70 ℃ for 9 minutes to obtain a polarizer for ultraviolet region. On the other hand, both sides of a triacetyl cellulose FILM (ZRD-60 manufactured by fuji FILM) containing no ultraviolet absorber were treated with a 1.5-equivalent aqueous solution of sodium hydroxide at 35 ℃ for 10 minutes, washed with water, dried at 70 ℃ for 10 minutes, laminated on both sides of the manufactured polarizer for ultraviolet region via an aqueous solution containing 4% of polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, japan), dried at 70 ℃ for 8 minutes, and provided with an antireflection layer (AR layer) on the surface to obtain a J polarizer for ultraviolet region having a light intensity-corrected monomer transmittance of 90.26% constituted as an AR layer/TAC/polarizer for ultraviolet region/TAC/AR layer.

Shown in table 5: the obtained polarizing plate J for ultraviolet region was measured at 375nm and λ max (405nm) for each of Ky, Kz, monomer transmittance Ts, orthogonal transmittance Tc, polarization ρ, and light intensity-corrected monomer transmittance (Ys) obtained every 5 nm; in fig. 6 is shown: ky and Kz for each wavelength of the obtained polarizing plate for ultraviolet region. As is clear from table 5 and fig. 6, the polarizing plate for the ultraviolet region used in the present application has high polarization characteristics in the range of 350 to 450 nm.

[ Table 5]

< example 1 >

The polarizing light-emitting panel A and the optical filter G (neutral length filter ND-0.1 manufactured by Fuji FILM Co., Ltd.) were bonded with an adhesive (PTR-3000 manufactured by Nippon chemical Co., Ltd.) to obtain an optical system of the present invention. As is clear from tables 1, 2 and 4, the optical system satisfies formula (2).

< example 2 >

The polarizing light-emitting panel a and the optical filter F, TAC having an adhesive function are bonded in this order to form the optical system of the present invention. As is clear from tables 1, 2 and 4, the optical system satisfies the formula (1) and the formula (2).

< example 3 >

The polarizing light-emitting panel a and the polarizing plate a were bonded together with an adhesive (PTR-3000, japan chemical industries, inc.) so that the axis (the alignment axis of the polarizing luminescent dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount of the polarizing plate a were orthogonal to each other, to obtain an optical system of the present invention. As is clear from tables 1, 2 and 3, the optical system satisfies expressions (2), (3) and (4).

< example 4 >

The polarizing light-emitting panel a and the polarizing plate D were bonded together with an adhesive (PTR-3000, japan chemical industries, inc.) so that the axis (the alignment axis of the polarizing luminescent dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount are orthogonal to each other, to obtain an optical system of the present invention. As is apparent from tables 1, 2 and 3, the optical system satisfies formulas (1), (2), (3) and (4).

< example 5 >

The polarizing light-emitting panel B was bonded with an adhesive (PTR-3000, manufactured by japan chemical industries) so that the axis (the orientation axis of the polarizing light-emitting dye) having the highest light absorption amount and the axis (the orientation axis of the dichroic dye) having the highest light absorption amount of the polarizing plate B were orthogonal to each other, to obtain an optical system of the present invention. As is clear from table 1, table 2 and table 3, the optical system satisfies formula (1), formula (2), formula (3) and formula (4).

< example 6 >

The polarizing light-emitting panel B and the polarizing plate a were bonded together with an adhesive (PTR-3000, japan chemical industries, inc.) so that the axis (the alignment axis of the polarizing luminescent dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount of the polarizing plate a were orthogonal to each other, to obtain an optical system of the present invention. As is apparent from tables 1, 2 and 3, the optical system satisfies formulas (1), (2), (3) and (4).

< example 7 >

The polarizing light-emitting panel B was bonded with an adhesive (PTR-3000, manufactured by japan chemical industries) so that the axis (the alignment axis of the polarizing luminescent dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount of the polarizing plate D were orthogonal to each other, to obtain an optical system of the present invention. As is apparent from tables 1, 2 and 3, the optical system satisfies formulas (1), (2), (3) and (4).

< example 8 >

The polarizing light-emitting panel C was bonded to the polarizing plate C with an adhesive (PTR-3000, japan chemical company) so that the axis (the alignment axis of the polarizing luminescent dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount of the polarizing plate C were orthogonal to each other, to obtain an optical system of the present invention. As is apparent from tables 1, 2 and 3, the optical system satisfies formulas (1), (2), (3) and (4).

< example 9 >

The polarizing light-emitting panel C and the polarizing plate B were bonded together with an adhesive (PTR-3000, japan chemical industries, inc.) so that the axis (the alignment axis of the polarizing light-emitting dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount are orthogonal to each other, to obtain an optical system of the present invention. As is clear from table 1, table 2 and table 3, the optical system satisfies formula (1), formula (2), formula (3) and formula (4).

< example 10 >

The polarizing light-emitting panel a and the polarizing plate E were bonded together with an adhesive (PTR-3000, japan chemical industries, inc.) so that the axis (the alignment axis of the polarizing light-emitting dye) having the highest light absorption amount and the axis (the alignment axis of the dichroic dye) having the highest light absorption amount are orthogonal to each other, to obtain an optical system of the present invention. As is clear from tables 1, 2 and 3, the optical system satisfies the formula (2) and the formula (4).

< comparative example 1 >

Only the polarized light emitting panel a was used as the sample of comparative example 1 having no visible light absorption filter.

< comparative example 2 >

The polarizing light-emitting panel a and the optical filter H, TAC having an adhesive function are sequentially bonded to each other to form an optical system. As is clear from tables 1, 2 and 3, the optical system does not satisfy the formulas (1) and (2).

< comparative example 3 >

Only the polarized light emitting panel B was used as the sample of comparative example 3 having no visible light absorption filter.

< comparative example 4 >

The polarizing light-emitting panel B was bonded with an adhesive (PTR-3000, japan chemical company) so that the axis (the orientation axis of the polarizing light-emitting pigment) having the highest light absorption amount and the axis (the axis of the iodine-based polarizing plate SKN-18243P) having the highest light absorption amount were orthogonal to each other, to prepare a sample for a comparative example.

< comparative example 5 >

Only the polarizing light-emitting panel C was used as a comparative sample without a visible light absorption filter.

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 (an LED M375L4 ° with a mount, manufactured by THORLABS) was used as a light source, and a liquid crystal cell was used as a phase control medium, and the light source, the ultraviolet region polarizing plate J, the liquid crystal cell, the optical system of the present invention, and the sample for comparison were arranged in this order to produce a polarized light emission display device. The optical systems of examples 3 to 10 or the samples of comparative examples 1 and 3 to 5 were bonded so that the polarizing light-emitting panel was positioned on the liquid crystal cell side, and irradiation of polarized light from the ultraviolet region polarizing plate J was performed so as to irradiate the polarizing light-emitting panel side with the liquid crystal cell interposed therebetween. The optical systems of examples 1 and 2 and comparative example 2 were each formed by laminating a polarizing light-emitting panel, a filter, and TAC in this order on a liquid crystal cell, and irradiation of polarized light from the ultraviolet region polarizing plate J was performed so as to irradiate the polarizing light-emitting panel side.

In the obtained polarized light emitting display device, light in the ultraviolet region to the near-ultraviolet visible region was irradiated from a 375nm LED light source through an ultraviolet region polarizing plate J, and the respective light emission intensities (luminances) in the bright state and the dark state at the time of driving the liquid crystal cell were measured using a 2-dimensional color luminance meter (promeric IC-PMI2 manufactured by KONICAL MINOLTA corporation) while using the optical systems of examples 1 to 10 and the display devices using the samples of comparative examples 1 to 5. The liquid crystal cell used was a liquid crystal cell (KSRS-05/B111M 1NSS05 manufactured by EHC) in which a liquid crystal (ZLI-1083 manufactured by MERCK) was sealed. The light emission intensity (luminance) in the bright state and the dark state of the present application is evaluated as a value between the time of no applied voltage (0V) and the time of application of applied voltage 4V.

In Table 6 are shown: photometrically corrected monomer transmittance (Ys- _sys ) Color phase (a) of the liquid crystal cell ^＊ -s、b ^＊ S), and the luminance (EM-) of a display device capable of polarized light emission using the liquid crystal cell in the bright state _SYS-H ) Emission luminance in the dark state (EM- _SYS-L ) Contrast of bright and dark states (CR- _SYS )。

[ Table 6]

As is clear from the results in table 6, the display device using the optical system satisfying the formula (1) and/or the formula (2) has a photometric corrected monomer transmittance of 50% or more, and also shows a high contrast. Optical System (a) of the present invention ^＊ -s、b ^＊ When s) is a color having a neutral color, it is known thatThe liquid crystal cell and the display device using the optical system of the present invention also have neutral colors. In addition, as is clear from comparison between example 1 and example 3, although the visible light absorption filter having the same transmittance of the single body for light intensity correction was provided, the display device using the optical system of the present invention had a high transmittance and a high contrast in the case where the visible light absorption filter was a polarizing plate as in example 3. The contrast of the display devices in these examples was significantly high compared to the cases of comparative examples 1, 3, and 5 using only the polarizing light-emitting panel, or using the filters having a transmittance of 90% which do not satisfy formulas (1) and (2), and thus the superiority of the optical system of the present invention was found. In addition, as is apparent from comparison of examples 5 to 7 with comparative example 4, it is shown that a display device having a high transmittance and a high light emission luminance as compared with the case of using a general polarizing plate can be obtained.

[ industrial applicability ]

The optical system of the present invention can provide high contrast when emitting a bias light. In one aspect, the optical system of the present invention can improve the contrast of the emission luminance in each axis of the film and has a high transmittance in the visible light region. Therefore, in one aspect, the optical member and the display device including the lens and the like of the optical system of the present invention have high transparency in the visible light region and can display an image by polarized light, and thus can be applied to a wide range of applications such as televisions, personal computers, tablet personal computer terminals, lenses, and further See-through displays (See-through displays). In addition, since light can be emitted by ultraviolet light, in one aspect, the polarized light emitting element and the polarized light emitting panel of the present invention can be applied to a functional medium such as a display and a sensor, which are required to have high safety and to be able to exhibit a function by irradiation with invisible light such as ultraviolet light that is difficult to be visually recognized by human eyes.

Claims

1. An optical system comprising a polarized light emitting element and a filter,

the filter can absorb light in a visible light region with the transmittance of the photometric correction monomer of 45 to 100 percent; and is provided with

The optical system satisfies the relationship of the formula (1) or the 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 F represents the absorbance at the maximum absorption wavelength of the axis on which the light absorption amount of the polarized light emitting element is the lowest _em-L Quantum yield of axis representing lowest light absorption amount of polarized light emitting element, A _fi-em-λmax An absorbance of the filter indicating a maximum emission wavelength of the polarized light emitting element;

0<TAF _em-L <0.7×TA _fi-em formula (2)

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

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

4. The optical system according to any one of claims 1 to 3, 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 type (3)

5. The optical system according to any one of claims 1 to 4, wherein the aforementioned filter is a polarizing element satisfying formula (4),

0<TAF _em-L <0.7×TA _pol-Kz-em formula (4)

6. The optical system according to any one of claims 1 to 5, wherein the filter is a polarizing element, and the polarizing light-emitting element and the filter are provided so that an axis along which an amount of light emitted by the polarizing light-emitting element is the weakest and an axis along which an absorbance of the polarizing element is high are parallel to each other.

7. The optical system according to any one of claims 1 to 6, wherein the color phase of the aforementioned optical filter is-5<a ^＊ <+3 and b ^＊ <±3。

8. The optical system according to any one of claims 1 to 7, wherein the polarized light emitting element contains a polarized light emitting pigment, and the polarized light emitting pigment is oriented.

9. The optical system according to any one of claims 1 to 8, wherein the polarized light emitting element emits polarized light by absorbing light in an ultraviolet region to a near-ultraviolet visible region.

10. The optical system according to any one of claims 1 to 9, wherein the polarized light emitting element has a maximum absorption wavelength of light in an ultraviolet region to a near-ultraviolet visible region.

11. The optical system according to any one of claims 1 to 10, wherein the polarized light emitting element and the filter are stacked.

12. The optical system according to any one of claims 1 to 11, which is provided with a phase difference plate.

13. The optical system according to any one of claims 1 to 12, wherein the aforementioned optical filter is located on a visual recognition side.

14. A display device provided with the optical system according to any one of claims 1 to 13.