WO2019022212A1

WO2019022212A1 - Polarized-light-emitting element, polarized-light-emitting plate, display device, and method for manufacturing polarized-light-emitting element

Info

Publication number: WO2019022212A1
Application number: PCT/JP2018/028164
Authority: WO
Inventors: 陵太郎森田; 典明望月
Original assignee: 日本化薬株式会社; 株式会社ポラテクノ
Priority date: 2017-07-28
Filing date: 2018-07-26
Publication date: 2019-01-31
Also published as: TWI783016B; TW201910439A; JP7287889B2; CN110832363A; JPWO2019022212A1; CN110832363B

Abstract

The present invention relates to a polarized-light-emitting element that exhibits polarized-light emission having a high degree of polarization (contrast) and that can also be applied to a liquid crystal display or the like in which high durability in harsh environments is required, to a polarized-light-emitting plate and a display device, and to a method for manufacturing the polarized-light-emitting element. In such a polarized-light-emitting element, at least one type of polarized-light-emitting pigment capable of utilizing light absorption to emit polarized light is arranged on a substrate, the polarized-light-emitting pigment exhibiting a light-polarizing effect in the wavelength region of the absorbed light, and the value of the order parameter (OPD) calculated by a predetermined formula (I) being 0.81-0.95 at the wavelength at which the light-polarizing effect is highest.

Description

Polarized light emitting element, polarized light emitting plate, display device, and method of manufacturing polarized light emitting element

The present invention relates to a polarized light emitting element having high durability and exhibiting polarized light emission having a high degree of polarization (contrast), a polarized light emitting plate and a display using the same, and a method of manufacturing the polarized light emitting element.

A polarizing plate having a light transmitting / shielding function is a basic component of a display device such as a liquid crystal display (LCD) together with a liquid crystal having a light switching function. The application fields of this LCD also include small devices such as calculators and watches in the early days, as well as notebook computers, word processors, liquid crystal projectors, liquid crystal televisions, car navigation systems, indoor and outdoor information display devices, measuring devices, and the like. In addition, such a polarizing plate is also applicable to a lens having a polarization function, and is also applied to sunglasses with improved visibility, polarization glasses corresponding to 3D TVs and the like in recent years, and wearables. Applications and practical applications to familiar information terminals such as terminals have also been made. As described above, since the use of the polarizing plate is in a wide range, the conditions of use are also widely applied such as low temperature to high temperature, low humidity to high humidity, low light amount to high light amount, and the like. Therefore, in order to correspond to application to each use, a polarizing plate having high polarization performance and excellent durability is required.

In general, a polarizing film constituting a polarizing plate is a film of a stretched or oriented polyvinyl alcohol or a derivative thereof, or a polyene produced by forming a polyene by dehydrochlorination of a polyvinyl chloride film or dehydration of a polyvinyl alcohol film. The film is produced by dyeing or containing iodine or a dichroic dye as a dichroic dye on a substrate such as a film of Since the polarizing plate configured of such a conventional polarizing film uses a dichroic dye having a light absorbing function in the visible light region, the transmittance in the visible light region is reduced. For example, the transmittance of a general polarizing plate commercially available is 35 to 45%.

The reason why the transmittance in the visible light region is as low as 35 to 45% is because a dichroic dye is used in the polarizing plate. In order for the polarizing plate to exhibit a degree of polarization of 100%, light in one axis needs to be absorbed when light in the x-axis and y-axis is present in a two-dimensional plane. A dichroic dye is used in the polarizing plate in order to absorb light of either one of the uniaxials. Therefore, the transmittance in the visible light region is theoretically 50% or less with respect to the light amount of 100%. Furthermore, the transmittance drops further than 50% of the theoretical value due to the orientation of the dichroic dye, the light loss by the film medium, and the interfacial reflection of the film surface. In view of the problem that the transmittance of the conventional polarizing plate becomes low, Patent Document 1 describes a polarizing plate for ultraviolet light as a technology for imparting a polarizing function while maintaining a constant transmittance in the visible light region. It is done. However, when this UV polarizing plate is used, the polarizing plate is colored yellow, and only a polarizing plate that can exhibit a polarizing function with light of about 410 nm can be provided. That is, such a polarizing plate for ultraviolet light was not a polarizing plate exhibiting a polarizing function in the visible light region, and was a polarizing plate functioning only in a specific ultraviolet or visible light region.

Usually, when a polarizing plate having a low transmittance in the visible light region or a polarizing plate having a low degree of polarization is used for a display or the like, the brightness or contrast of the entire display is lowered. In order to solve this problem, methods for obtaining polarization without using a conventional polarizing plate have been studied. As one of the methods, Patent Documents 2 to 6 disclose elements (polarized light emitting elements) that exhibit polarized light emission.

International Publication No. 2005/01527 JP 2008-224854 A Patent No. 5849255 Patent No. 5713360 U.S. Pat. No. 3,276,316 JP-A-4-226162

However, the polarized light emitting elements described in Patent Documents 2 to 4 use special metals, for example, metals having high rare value such as lanthanoids and europium. Therefore, the cost is high, and it is not suitable for mass production because the production is very difficult. Furthermore, these polarized light emitting elements are very difficult to use in displays due to their very low degree of polarization, and it is very difficult to obtain linearly polarized light emission. In addition, there is also a problem that only circularly polarized light or elliptically polarized light of a specific wavelength can be obtained as light emission. Therefore, even when the polarized light emitting elements described in Patent Documents 2 to 4 are used for displays, there are disadvantages such as dark emission luminance, low contrast, and difficulty in designing a liquid crystal cell.

On the other hand, Patent Documents 5 and 6 disclose elements which emit polarized light to emit ultraviolet light. However, there is a problem that the degree of polarization of light emitted from the device is low and the durability of the device is low. In general, it is known that when the contrast value exceeds 10, the visibility by human eyes is dramatically improved. For example, the contrast value of characters such as newspapers and magazines is about 10. Therefore, even in consideration of actual use for a liquid crystal display, the contrast value exceeding 10 is a value necessary for securing visibility.

The element showing polarized light emission described in Patent Documents 5 and 6 uses a polyvinyl alcohol film as a substrate at the time of production, but the contrast value of polarized light is lower than 10, and from the viewpoint of visibility Was also unsuitable for application to liquid crystal displays. In view of such drawbacks of the conventional polarizing element, a liquid crystal display exhibiting a polarized light emitting action, having a high degree of polarized light emission, and further having high transmittance in the visible light region and durability in severe environments It is desired to develop a new polarizing plate that can also be applied to the like and materials therefor.

The present invention exhibits polarized light emission having a high degree of polarization (contrast), and is also applicable to a liquid crystal display or the like where high durability is required under severe environments, a polarized light emitting plate using the same, An object of the present invention is to provide a display device and a method of manufacturing the polarized light emitting device.

As a result of intensive studies to achieve such an object, the inventors of the present invention are directed to a polarized light emitting element in which at least one polarized light emitting dye capable of polarized light emission is oriented on a substrate by using light absorption. It has been found that the value of the order parameter based on the absorption of light of the polarized light-emitting dye significantly affects the degree of polarization of the emitted light, particularly the contrast. And based on the said knowledge, by controlling the value of the order parameter based on absorption of the light of polarization light-emitting pigment, the polarization light-emitting element which can emit light having high degree of polarization (contrast) while having high durability It was found that was obtained.

That is, the gist configuration of the present invention is as follows.
1)
A polarized light emitting element in which at least one polarized light emitting dye capable of polarized light emission is oriented on a substrate by using absorption of light,
The polarized light emitting dye exhibits a polarization action in the wavelength region of the absorbed light, and at the wavelength at which the polarization action is the highest, the value of the order parameter (OPD) calculated by the following formula (I) is 0. Polarized light-emitting element having a wavelength of 81 to 0.95.

(In the above formula (I), Ky represents the light transmittance when light polarized orthogonal to the axis showing absorption of the highest light in the polarized light emitting element is incident, and Kz represents the polarized light emission Indicates the light transmittance when light polarized parallel to the axis showing the highest light absorption in the device is incident.)
2)
The polarized light emitting device according to 1) above, wherein the at least one polarized light emitting dye has a fluorescence emitting property.
3)
The above-mentioned 1) or 2) described in the above 1) or 2), wherein the at least one polarized light-emitting dye has fluorescence emission characteristics capable of polarized light emission of light in the visible light region by absorbing light in the ultraviolet light region Polarized light emitting element.
4)
The polarized light-emitting device according to any one of the above 1) to 3), wherein the at least one polarized light-emitting dye has a biphenyl skeleton or a stilbene skeleton.
5)
The above-mentioned 4), wherein the polarized light-emitting element exhibits an emission color having an absolute value of chromaticity a ^* of 5 or less and an absolute value of hue b ^* of 5 or less measured according to JJIS Z 8781-4: 2013. The polarized light emitting element as described in.
6)
The polarized light-emitting device according to the above 4) or 5), wherein the at least one polarized light-emitting dye is a compound represented by the following formula (1) or a salt thereof.

(Wherein, L and M each independently represent a nitro group, an amino group which may have a substituent, a carbonylamide group which may have a substituent, a naphthotriazole group which may have a substituent) A C ₁ -C ₂₀ alkyl group which may have a substituent, a vinyl group which may have a substituent, an amido group which may have a substituent, a ureide group which may have a substituent, It is selected from the group consisting of an aryl group which may have a substituent and a carbonyl group which may have a substituent.)
7)
The polarized light-emitting device according to the above 6), wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or formula (3).

(In formula (2), X represents a nitro group or an amino group which may have a substituent,
R may have 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 a substituent Represents a good amino group,
n represents an integer of 0 to 3. )

(In the formula (3), Y is a C ₁ -C ₂₀ alkyl group which may have a substituent, a vinyl group which may have a substituent, or an aryl group which may have a substituent And Z represents a nitro group or an amino group which may have a substituent.)
8)
In the above formula (2), X is a nitro group, a C ₁ -C ₂₀ alkylcarbonylamino group which may have a substituent, an arylcarbonylamino group which may have a substituent, C ₁ -C ₂₀ alkylsulfonyl The polarized light-emitting device according to the above 7), which is an amino group or an arylsulfonylamino group which may have a substituent.
9)
The polarized light-emitting device according to the above 7) or 8), wherein, in the formula (2), R is a hydrogen atom and n is 1 or 2.
10)
The polarized light-emitting element according to the above 7) or 8), wherein in the formula (2), R is a methyl group.
11)
The polarized light-emitting device according to any one of 7) to 10) above, wherein in the formula (3), Y is an aryl group which may have a substituent.
12)
12. The polarized light-emitting device according to any one of 1) to 11), wherein the substrate contains a hydrophilic polymer.
13)
12. The polarized light-emitting device according to 12), wherein the hydrophilic polymer contains polyvinyl alcohol.
14)
The polarized light-emitting device according to any one of 1) to 13), wherein the substrate is an oriented hydrophilic polymer film.
15)
The polarized light-emitting device according to any one of the above 1) to 14), wherein the substrate further comprises a boron compound.
16)
The secondary ion intensity derived from the boron compound measured by time-of-flight secondary ion mass spectrometry in the thickness direction of the substrate satisfies the relationship of I ₂ ≦ 30 × I ₁ ,
I ₁ is secondary ion intensity detected in the thickness detected maximum secondary least distance 1 / 2L toward the one side surface in the thickness direction of the relative ionic strength substrate at L of the base material Represents the ratio of
I ₂ is detected between a distance of 1/4 L from the both surfaces of the substrate to the maximum secondary ion intensity detected at the thickness L of the substrate respectively in the thickness direction of the substrate 15. The polarized light-emitting device according to the above 15), which represents the maximum value of the ratio of the secondary ion intensities.
17)
The secondary ion intensity derived from the boron compound further satisfies the relationship of I ₃ ≦ 5 × I ₄ ,
I ₃ is the ratio of the secondary ion intensity detected between the distance of 1 / 4L from at least one side surface of said substrate with respect to the maximum secondary ion intensity detected by the thickness L of the base material Represents the average value,
I ₄ is a distance of 1⁄4 L in the thickness direction from the center of the thickness L to the maximum secondary ion intensity detected at the thickness L of the substrate toward both surfaces of the substrate The polarized light-emitting device according to the above 16), which represents the average value of the ratio of secondary ion intensities detected between the two.
18)
The secondary ion intensity derived from the boron compound further satisfies the relationship of I ₅ ≦ 2 × I ₆ ,
I ₅ is the ratio of the secondary ion intensity detected between the distance of 1 / 4L from at least one side surface of said substrate with respect to the maximum secondary ion intensity detected by the thickness L of the base material Represents an integral value,
I ₆ up to a distance of 1⁄4 L each in the thickness direction from the center of the thickness L to the maximum secondary ion intensity detected at the thickness L of the substrate from the center to both surfaces of the substrate The polarized light-emitting element according to the above 16) or 17), which represents an integral value of the ratio of secondary ion intensities detected therebetween.
19)
The polarized light-emitting element according to any one of the above 16) to 18), wherein the concentration distribution of the secondary ion intensity derived from the boron compound is present at least between 3 μm and 20 μm from the surface of the substrate.
20)
The polarized light emitting device according to any one of 1) to 19), wherein the polarized light emitting device further comprises at least one organic dye and / or a fluorescent dye different from the polarized light emitting dye.
21)
The polarized light emitting device according to any one of the above 1) to 20), further comprising a visible light absorbing dye-containing layer on at least one surface of the polarized light emitting device.
22)
22. The polarized light emitting device according to 21), wherein the visible light transmittance of the visible light absorbing dye-containing layer has a reduction rate of 50% or less.
23)
The above-mentioned 21), wherein the visible light absorbing dye-containing layer has light absorption anisotropy, and the light absorption direction based on the light absorption anisotropy is orthogonal to polarized light emission by the polarized light emitting element. Or 22).
24)
A polarized light emitting plate comprising the polarized light emitting device according to any one of the above 1) to 23) and a transparent protective layer provided on one side or both sides of the polarized light emitting device.
25)
The polarized light-emitting plate according to the above 24), wherein the transparent protective layer is a plastic film having no ultraviolet light absorption function.
26)
The polarized light-emitting plate according to the above 24) or 25), further comprising a support layer.
27)
A display device comprising the polarized light-emitting element according to any one of 1) to 23) or the polarized light-emitting plate according to any one of 24) to 26).
28)
A visible light absorbing dye-containing layer is further provided on at least one surface of the polarized light emitting element, and
27. The display device according to 27), wherein the visible light absorbing dye-containing layer is provided at least on the viewer side.
29)
The polarized light emission according to any one of the above 15) to 19), wherein the substrate is stretched while containing the boron compound in the substrate containing the polarized light-emitting dye, or is stretched after containing the boron compound in the substrate Method of manufacturing a device

According to the present invention, in a polarized light emitting element in which at least one polarized light emitting dye capable of polarized light emission is oriented on a substrate using absorption of light, the polarized light emitting dye is in the wavelength region of the absorbed light The value of the order parameter (ОPD) calculated by a predetermined equation is controlled to 0.81 to 0.95 at a wavelength that exhibits the polarization action and the polarization action is the highest. That is, for example, in a polarized light emitting dye that exhibits polarized light emission in the visible light region by absorbing light in the ultraviolet light region, the light emission amount of the strong axis and the light emission amount of the weak axis are controlled. Thereby, the contrast of polarized light emission in the visible light region can be dramatically improved, and as a result, a polarized light emitting element exhibiting polarized light emission having a high degree of polarization (contrast) and a polarized light emitting plate using the same are provided. can do. In addition, a polarized light emitting element having a high degree of polarization and a polarized light emitting plate using the same can be provided without using a highly rare earth metal such as a lanthanoid metal. Furthermore, the polarized light emitting element according to the present invention and the polarized light emitting plate using the same exhibit excellent durability against heat, humidity and the like. Therefore, the polarized light emitting element and the polarized light emitting plate including the same can be applied to a display device such as a liquid crystal display which is required to have high transparency in a visible light region and high durability under a severe environment.

FIG. 1 is a view showing the relationship between the value of OPD and the value of RCE of the polarized light emitting elements manufactured in Examples 1 to 7 and Comparative Examples 1 and 2. FIG. 2 is a view showing the relationship between the value of OPD and the value of RCE of the polarized light emitting elements manufactured in Examples 8 to 13 and Comparative Examples 3 to 6.

<Polarized light emitting element>
The polarized light emitting element according to the present invention is a polarized light emitting element in which at least one type of polarized light emitting dye capable of polarized light emission is oriented on a substrate by utilizing absorption of light. In addition, the polarized light emitting dye exhibits a polarization action in the wavelength range of the absorbed light, and the value of the order parameter (OPD) calculated by the following formula (I) is 0.81 at the wavelength at which the polarization action is the highest. It is ̃0.95.

In the above-mentioned formula (I), Ky represents the light transmittance when light polarized orthogonal to the axis showing absorption of the highest light in the polarized light emitting element is incident. On the other hand, Kz represents the light transmittance when light polarized parallel to the axis showing absorption of the highest light in the polarized light emitting element is incident.

A polarized light-emitting dye capable of emitting polarized light using absorption of light generally belongs to a fluorescent dye or a phosphorescent light-emitting dye, but specifically, it absorbs specific light and emits light energy using the light Refers to a dye that can be converted to As such a dye, any of a fluorescent dye and a phosphorescent dye may be used, but it is preferable to use a fluorescent dye. In addition, the wavelength of the absorbed light and the light to be emitted are often different, and the dye may be also referred to as a wavelength conversion dye. As described above, at least one type of polarized light emitting dye contained in the polarized light emitting element preferably has fluorescence emission characteristics, and in particular, by absorbing light in the ultraviolet light region to the near ultraviolet visible light region, the visible light region is It is more preferable to have fluorescence emission characteristics capable of polarized light emission.

In addition, as in the case of a dichroic dye, the polarized light-emitting dye has light absorption anisotropy between the axis oriented to the base and the orthogonal axis, as in the dichroic dye, and thus the light absorption anisotropy That is, it expresses a polarization function.

Focusing on the transmittance of each wavelength of the polarized light-emitting dye that has developed the polarization function, when light polarized parallel to the axis showing the highest light absorption is incident on the polarized light-emitting element in which the polarized light-emitting dye is oriented Light transmittance (that is, the transmittance at the axis where the amount of light transmission is small) is Kz, while polarized at a position orthogonal to the axis showing the highest absorption in the polarized light emitting element in which the polarized light emitting dye is oriented. The light transmittance when light is incident (that is, the transmittance at the axis where the amount of light transmission is large) is taken as Ky. Then, by substituting these Ky and Kz into the above formula (I), the order parameter, that is, the degree of orientational order can be calculated.

The order parameter (orientational order degree) is generally used as an index used to measure the orientation of substances such as liquid crystals, and the higher the value of the order parameter, the higher the value of the polarization light emitting element has higher alignment order. Show that. Generally, the calculation formula of the value of the order parameter is expressed as the following formula (II) (refer to "Display material and functional pigment (CMC publication, Hiroyuki Nakasumi, P65)", formula (II) The following equation (III) is derived by converting the equation represented by). By further transforming this formula (III), the order parameter (OPD) can be represented by the above formula (I). In this case, as a factor in the formulas (II) and (III), A _PARA is absorbance parallel to the direction of the oriented polarized light-emitting dye, and A _CROSS is orthogonal to the direction of the oriented dye Absorbance of The absorbance of each is calculated by Log (A), and by substituting the absorbance obtained by Ky and Kz into Equation (III) for each absorbance calculated by Log (A), Equation (I) is derived. . Based on this formula (I), absorption of light is used to control the degree of orientational order of the dye capable of polarized light emission, whereby a polarized light emitting element exhibiting polarized light emission having a high contrast value can be obtained. Thus, by controlling the value of the order parameter in the range of 0.81 to 0.95, it is possible to obtain polarized light emission having a high contrast value, and the value of the order parameter is 0.83 to 0.95. Is preferably in the range of 0.85 to 0.94, and more preferably in the range of 0.87 to 0.93. The value of the order parameter is preferably as high as possible, but when the value of the order parameter is larger than 0.95, the contrast value of the polarized light emission is not necessarily high, and the stability is lacking. Therefore, the upper limit of the value of the order parameter is set to 0.95 in order to obtain a polarized light emitting element that exhibits polarized light emission with high contrast stably in production.

OPD = (A _PARA- A _CROSS ) / (A _PARA + 2 x A _CROSS ) (II)

OPD = (A _PARA / A _CROSS -1) / (A _PARA / A _CROSS +2) (III)

A polarized light emitting element showing polarized light emission is obtained by containing one or a plurality of polarized light emitting dyes in a base material and orienting the same. Such a polarized light emitting element exhibits various emission colors by adjusting the blending ratio of the polarized light emitting dye. For example, when the absolute value of chromaticity a ^* measured according to JIS Z 8781-4: 2013 is 5 or less and the absolute value of hue b ^* is 5 or less, the emission color from the polarized light emitting element is white Indicates The chromaticity a ^* value and the hue b ^* value in accordance with the standard of JIS Z 8781-4: 2013 are values obtained at the time of measuring the hue of light. The display method of the object color defined in the standard corresponds to the display method of the object color defined by the International Commission on Illumination (abbr .: CIE). The measurement of chromaticity a ^* value and b ^* value is usually performed by irradiating natural light to the measurement sample, but in the polarized light emitting element used in the present invention, light of short wavelength such as ultraviolet light is used for the polarized light emitting element. The chromaticity a ^* value and the b ^* value can be confirmed by measuring the light emitted from the polarized light emitting element. Even when light in the ultraviolet light region is irradiated, white polarized light emission is exhibited because the absolute value of the chromaticity a ^* of light exhibiting polarized light emission is 5 or less and the absolute value of the hue b ^* is 5 or less It means that a polarized light emitting element is obtained. If the absolute value of the chromaticity a ^* of the emitted polarized light is 5 or less, it can be perceived as white, but preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, particularly preferably 1 or less. Further, as the hue b ^* be the emitted light, as long as the absolute value of the hue b ^* is 5 or less, it can be perceived as white, preferably 4 or less, more preferably 3 or less, more preferably 2 or less, particularly Preferably it is 1 or less. Thus, if the absolute values of the chromaticity a ^* and b ^* are independently 5 or less, it can be perceived as white by the human eye, and it is more preferable if both are 5 or less. It can be perceived as white light emission. Since the polarized light to be emitted is white, it can be used as a natural light source such as sunlight, a light source for paper white terminals and the like. Therefore, such a polarized light emitting element can be utilized as a white polarized light emitting polarized light emitting element, and application to a display using a color filter or the like is simple. In addition, about the emitted light intensity of white light, if emitted light can be visually detected, it is possible to apply to a display. In order for the light emission to be sensed visually, it is particularly important that the light emission has a high degree of polarization and that the transmission in the visible range is high.

<Polarized light emitting dye>
The polarized light emitting dye is preferably a compound having a stilbene skeleton or a biphenyl skeleton as a basic skeleton or a salt thereof. The polarization light emitting dye having such a basic skeleton is oriented to the base material so that the value of the order parameter is controlled in the range of 0.81 to 0.95 while showing the fluorescence emission characteristic. It is possible to emit light having a higher degree of polarization than other polarized light emitting dyes, that is, light having high contrast. The stilbene skeleton and the biphenyl skeleton as the basic skeleton of the polarized light emitting dye have the function of exhibiting fluorescence properties by the respective skeletons themselves and exhibiting high dichroism by orienting on the substrate. Since this action is due to the structures of the basic skeletons of the stilbene skeleton and the biphenyl skeleton, further arbitrary substituents may be bonded to the basic skeleton structure. However, when an azo group is substituted in the basic skeleton structure, although a high degree of polarization can be realized as in a conventional dye-based polarizing plate, depending on the position at which the azo group is substituted, the amount of emitted light is significantly reduced. Sometimes light intensity can not be obtained. Therefore, when substituting an azo group in each basic skeleton, the substitution position becomes important. The polarized light emitting dyes may be used alone or in combination of two or more.

As described above, it is preferable that the polarized light emitting dye has fluorescence emission characteristics capable of polarized light of light in the visible light region by absorbing light in the ultraviolet light region to the near ultraviolet visible light region. Specifically, after the polarized light emitting dye is contained in the base material, irradiation with light in the ultraviolet light region to the near ultraviolet visible light region enables 0.04 μW in the visible light region, for example, the wavelength region of 400 to 700 nm. it may show polarized luminescence of / cm ² or more light-emitting intensity, preferably it is more indicative of the polarized luminescence of 0.05MyuW / cm ² or more light-emitting intensity, polarized luminescence of 0.1MyuW / cm ² or more luminous intensity More preferably, Although ultraviolet light generally indicates light in a wavelength range of 400 nm or less, light in a wavelength range of 430 nm or less is also extremely low as human visual sensitivity. Therefore, light in the ultraviolet light region to the near ultraviolet visible light region can be defined as light invisible to human eyes, and for example, light in the wavelength region of 300 nm to 430 nm is preferable. By using a polarized light emitting dye, it is possible to absorb invisible light and obtain a polarized light emitting element capable of polarized light emission.

(A) Polarized Light-Emitting Dye Having a Stilbene Skeleton The polarized light-emitting dye having a stilbene skeleton is preferably a compound represented by the following formula (1) or a salt thereof.

In the above formula (1), L and M each independently have a nitro group, an amino group which may have a substituent, a carbonylamide group which may have a substituent, or a substituent Naphthotriazole group, C ₁ -C ₂₀ alkyl group which may have a substituent, vinyl group which may have a substituent, amido group which may have a substituent, have a substitution It is selected from the group consisting of an optionally ureido group, or an optionally substituted aryl group and an optionally substituted carbonyl group, but is not limited thereto. The compound having a stilbene skeleton represented by the formula (1) exhibits fluorescence and dichroism can be obtained by orientation. Since the light emission characteristics are attributed to the stilbene skeleton, the substituent to which each of the L and M groups can be bound is not particularly limited as long as it has no azo group, and is any substituent. You may

As an amino group which may have a substituent, for example, an unsubstituted amino group;
Methylamino group, ethylamino group, n-butylamino group, tertiary butylamino group, n-hexylamino group, dodecylamino group, dimethylamino group, diethylamino group, di-n-butylamino group, ethylmethylamino group, A C ₁ -C ₂₀ alkylamino group which may have a substituent such as ethylhexylamino group;
An arylamino group which may have a substituent such as phenylamino group, diphenylamino group, naphthylamino group, N-phenyl-N-naphthylamino group;
A C ₁ -C ₂₀ alkylcarbonylamino group which may have a substituent such as a methylcarbonylamino group, an ethylcarbonylamino group, an n-butyl-carbonylamino group and the like;
An arylcarbonylamino group which may have a substituent such as phenylcarbonylamino group, biphenylcarbonylamino group, naphthylcarbonylamino group and the like;
It has a substituent such as C ₁ -C ₂₀ alkylsulfonylamino group such as methylsulfonylamino group, ethylsulfonylamino group, propylsulfonylamino group, n-butyl-sulfonylamino group, phenylsulfonylamino group, naphthylsulfonylamino group and the like And arylsulfonylamino which may be mentioned.

Among these amino groups, C ₁ -C ₂₀ alkylcarbonylamino group which may have a substituent, arylcarbonylamino group which may have a substituent, C ₁ -C ₂₀ alkylsulfonylamino group, a substituent The aryl sulfonylamino group which may have is preferable.

As a carbonylamido group which may have a substituent, for example, N-methyl-carbonylamido group (-CONHCH ₃ ), N-ethyl-carbonylamido group (-CONHC ₂ H ₅ ), N-phenyl-carbonylamido Groups (-CONHC ₆ H ₅ ) and the like.

As the C ₁ -C ₂₀ alkyl group which may have a substituent, for example, linear ones such as methyl group, ethyl group, n-butyl group, n-hexyl group, n-octyl group and n-dodecyl group Branched C ₃ -C ₁₀ alkyl group such as C ₁ -C ₁₂ alkyl group, isopropyl group, sec-butyl group, tert-butyl group, cyclic C ₃ -C ₇ alkyl group such as cyclohexyl group, cyclopentyl group and the like And the like. Among these, a linear or branched alkyl group is preferable, and a linear alkyl group is more preferable.

Examples of the vinyl group which may have a substituent include ethenyl group, styryl group, vinyl group having alkyl group, vinyl group having alkoxy group, divinyl group, pentadiene group and the like.

Examples of the amido group which may have a substituent include acetamide group (-NHCOCH ₃ ), benzamide group (-NHCOC ₆ H ₅ ) and the like.

Examples of the ureido group which may have a substituent include monoalkyl ureido group, dialkyl ureido group, monoaryl ureido group, and diaryl ureido group.

Examples of the aryl group which may have a substituent include phenyl group, naphthyl group, anthracenyl group, biphenyl group and the like, with preference given to C ₆ -C ₁₂ aryl group. The aryl group may be a 5- or 6-membered heterocyclic group containing 1 to 3 hetero atoms selected from the group consisting of nitrogen atom, oxygen atom and sulfur atom as ring member atoms. Among such heterocyclic groups, a heterocyclic group containing an atom selected from a nitrogen atom and a sulfur atom as a ring constituent atom is preferable.

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

The substituent mentioned above is not particularly limited, but, for example, nitro group, cyano group, hydroxyl group, sulfonic acid group, phosphoric acid group, carboxyl group, carboxyalkyl group, halogen atom, alkoxy group, aryloxy group Etc.

As a carboxyalkyl group, a methyl carboxyl group, an ethyl carboxyl group etc. are mentioned, for example. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned. As an alkoxy group, a methoxy group, an ethoxy group, a propoxy group etc. are mentioned. Examples of the aryloxy group include phenoxy group and naphthoxy group.

Examples of the compound represented by the formula (1) include Kayaphor series (manufactured by Nippon Kayaku Co., Ltd.), Whiteex RP and the like Whitetex series (manufactured by Sumitomo Chemical Co., Ltd.), and the like. Moreover, although the compound shown by Formula (1) below is illustrated, it is not limited to these.

Compound Example 1

It is preferable that it is a compound or its salt shown by following formula (2) or Formula (3) as another compound which has stilbene frame | skeleton. By using these compounds, it is possible to obtain a polarized light emitting element that emits sharper white light. Furthermore, the compounds represented by the following formulas (2) and (3) also exhibit fluorescence due to the stilbene skeleton, and dichroism can be obtained by orientation.

In the above formula (2), X represents a nitro group or an amino group which may have a substituent. The amino group which may have a substituent is defined in the same manner as the amino group which may have a substituent in the above formula (1). Among these, X is a nitro group, a C ₁ -C ₂₀ alkylcarbonylamino group which may have a substituent, an arylcarbonylamino group which may have a substituent, a C ₁ -C ₂₀ alkylsulfonylamino group Or an arylsulfonylamino group which may have a substituent is preferable, and a nitro group is particularly preferable.

In the above formula (2), R represents a hydrogen atom, a halogen atom such as a chlorine atom, a bromine atom or a fluorine atom, a hydroxyl group, a carboxyl group, a nitro group, an alkyl group which may have a substituent, a substituent Or an amino group which may have a substituent. The alkyl group which may have a substituent is defined in the same manner as the C ₁ -C ₂₀ alkyl group which may have a substituent in the above formula (1). The alkoxy group which may have a substituent is preferably a methoxy group or an ethoxy group. The amino group which may have a substituent is defined in the same manner as the amino group which may have a substituent in the above formula (1), preferably a methylamino group, a dimethylamino group, an ethylamino group, a diethylamino group. A group, or a phenylamino group or the like. R may be bonded to any carbon of the naphthalene ring in the naphthotriazole ring, but when the carbon fused to the triazole ring is at 1 and 2 positions, the 3, 5, or 8 position It is preferred that the Among these, R is preferably a hydrogen atom or a C ₁ -C ₂₀ alkyl group, and when R is a C ₁ -C ₂₀ alkyl group, it is preferably a methyl group.

In the above formula (2), n is an integer of 0 to 3, preferably 1. In the above formula (2), — (SO ₃ H) may be bonded to any carbon atom of the naphthalene ring in the naphthotriazole ring. The position of naphthalene ring in-(SO ₃ H) is 4-, 6-, or 7-position if n = 1 if the carbon atom fused to triazole ring is 1- or 2-position If n = 2, then it is preferred to be at the 5th and 7th positions and at the 6th and 8th positions, and if n = 3 it is a combination of the 3rd, 6th and 8th positions preferable. Among these, it is particularly preferable that R is a hydrogen atom and n is 1 or 2.

In formula (3), Y is a C ₁ -C ₂₀ alkyl group which may have a substituent, a vinyl group which may have a substituent, or an aryl group which may have a substituent Represents Among these, an aryl group which may have a substituent is preferable, and a naphthyl group which may have a substituent is more preferable, and a naphthyl group in which an amino group and a sulfo group are substituted as a substituent Is particularly preferred.

In formula (3), Z is defined in the same manner as X in formula (2) above, and represents a nitro group or an amino group which may have a substituent, and is preferably a nitro group.

The compound having a biphenyl skeleton is preferably a compound represented by the following formula (4) or a salt thereof.

In the above formula (4), P and Q each independently may have a nitro group, an amino group which may have a substituent, a carbonylamide group which may have a substituent, or a substituent A naphthotriazole group, a C ₁ -C ₂₀ alkyl group which may have a substituent, a vinyl group which may have a substituent, an amido group which may have a substituent, and a substituent It may be a ureido group which may be substituted, an aryl group which may have a substituent, or a carbonyl group which may have a substituent, but it is not limited thereto. However, when it has an azo group at the P position and / or the Q position of the biphenyl skeleton, the fluorescence emission is significantly reduced, which is not preferable.

The compound represented by the above formula (4) is preferably a compound represented by the following formula (5).

In the above formula (5), j represents an integer of 0 to 2. The position to which-(SO ₃ H) is bonded is preferably the 2-, 4- or 6-position, particularly preferably the 4-position, when the carbon atom to which -CH = CH- is bonded is 1-position. .

In the above formula (5), R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a C ₁ -C ₄ alkyl group, a C ₁ -C ₄ alkoxy group, an aralkyloxy group, an alkenyloxy group, C ₁ -C ₄ alkylsulfonyl group, C ₆ -C ₂₀ arylsulfonyl group, carbonamide group, sulfonamide group, carboxyalkyl group. The position to which R ₁ to R ₄ is bonded is not particularly limited, but when the vinyl group is at the 1st position, the 2nd, 4th and 6th positions are preferable, and the 4th position is particularly preferable.

Examples of the C ₁ -C ₄ alkyl group include methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, tert-butyl group, cyclobutyl group and the like.

Examples of the C ₁ -C ₄ alkoxy group include methoxy group, ethoxy group, propoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, cyclobutoxy group and the like.

As the aralkyloxy group, for example, a C ₇ -C ₁₈ aralkyloxy group and the like can be mentioned.

As the alkenyloxy group, for example, a C ₁ -C ₁₈ alkenyloxy group and the like can be mentioned.

Examples of the C ₁ -C ₄ alkyl sulfonyl group include methyl sulfonyl group, ethyl sulfonyl group, propyl sulfonyl group, n-butyl sulfonyl group, sec-butyl sulfonyl group, tertiary butyl sulfonyl group, cyclobutyl sulfonyl group and the like. Be

Examples of the C ₆ -C ₂₀ arylsulfonyl group include phenylsulfonyl group, naphthylsulfonyl group, biphenylsulfonyl group and the like.

The compound represented by the above formula (5) can be prepared by a known method, for example, can be synthesized by condensing 4-nitrobenzaldehyde-2-sulfonic acid with a phosphonate and then reducing the nitro group .
Specific examples of such a compound represented by the formula (5) include the following compounds described in JP-A-4-226162.

The salts of the compounds represented by the formulas (1) to (5) mean that the free acids of the respective compounds represented by the above formulas form salts with inorganic cations or organic cations. Examples of inorganic cations include alkali metals such as lithium, sodium, potassium and other cations, or ammonium (NH ₄ ⁺ ). Moreover, as an organic cation, the organic ammonium etc. which are represented by following formula (A) are mentioned, for example.

In formula (A), Z ₁ to Z ₄ each independently represent a hydrogen atom, an alkyl group, a hydroxyalkyl group or a hydroxyalkoxyalkyl group, and at least one of Z ₁ to Z ₄ is hydrogen It is a group other than an atom.

Specific examples of Z ₁ to Z ₄ include, for example, a C _{1 to} C ₆ alkyl group such as methyl group, ethyl group, butyl group, pentyl group and hexyl group, preferably a C _{1 to} C ₄ alkyl group; hydroxymethyl group Hydroxy C ₁ -C ₆ alkyl group such as 2-hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, 4-hydroxybutyl group, 3-hydroxybutyl group, 2-hydroxybutyl group, preferably hydroxy C ₁ -C ₄ alkyl group; and, hydroxyethoxy methyl group, 2-hydroxyethoxy ethyl group, 3-hydroxy-ethoxypropyl, 3-hydroxyethoxy-butyl group, 2-hydroxyethoxy butyl hydroxy _C 1 -C ₆ alkoxy C ₁ -C ₆ alkyl group, preferably a hydroxy _C 1 -C ₄ alkoxy _{C 1} - C ₄ alkyl group and the like.

Among these inorganic cations or organic cations, cations of sodium, potassium, lithium, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ammonium and the like are more preferable, Particular preference is given to inorganic cations of lithium, ammonium or sodium.

The polarized light emitting dye having the above structure does not have an azo group in the molecule, so that the absorption of light due to the azo bond is suppressed. In particular, a compound having a stilbene skeleton exhibits a light emitting action by irradiation with ultraviolet light, and the molecule is stabilized by the presence of a strong carbon-carbon double bond of the stilbene skeleton. Therefore, a polarized light emitting element using a polarized light emitting dye having such a specific structure can absorb light and utilize its energy to exhibit a polarized light emitting action in the visible light region.

(Other pigments)
The polarized light emitting element exhibiting the above-mentioned characteristics may further contain at least one kind of fluorescent dye and / or organic dye different from the above-mentioned polarized light emitting dye as long as the polarization performance of the polarized light emitting element is not impaired. As a fluorescent dye to be used in combination, for example, C.I. I. Fluorescent Brightener 5, C.I. I. Fluorescent Brightener 8, C.I. I. Fluorescent Brightener 12, C.I. I. Fluorescent Brightener 28, C.I. I. Fluorescent Brightener 30, C.I. I. Fluorescent Brightener 33, C.I. I. Fluorescent Brightener 350, C.I. I. Fluorescent Brightener 360, C.I. I. Fluorescent Brightener 365 etc. are mentioned.

As an organic dye, for example, C.I. Eye. direct. Yellow 12, Sea. Eye. direct. Yellow 28, Sea. Eye. direct. Yellow 44, C.I. Eye. direct. Orange 26, Sea. Eye. direct. Orange 39, Sea. Eye. direct. Orange 71, Sea. Eye. direct. Orange 107, C.I. Eye. direct. Red 2, Sea. Eye. direct. Red 31, Sea. Eye. direct. Red 79, Sea. Eye. direct. Red 81, Sea. Eye. direct. Red 247, Sea. Eye. direct. Blue 69, Sea. Eye. direct. Blue 78, Sea. Eye. direct. Green 80 and C.I. Eye. direct. Green 59 and the like. These organic dyes may be free acids or may be alkali metal salts (eg Na, K, Li), ammonium salts or salts of amines.

<Base material>
A polarized light emitting element comprises a substrate that can contain and can be oriented with a polarized light emitting dye. The substrate preferably contains a hydrophilic polymer capable of adsorbing a polarized light emitting dye and containing a boron derivative and being crosslinkable, and a hydrophilic polymer film obtained by forming the hydrophilic polymer into a film, in particular It is preferable that it is an oriented hydrophilic polymer film. The hydrophilic polymer is not particularly limited, but for example, polyvinyl alcohol resins and starch resins are preferable. The hydrophilic polymer preferably contains a polyvinyl alcohol-based resin or a derivative thereof from the viewpoint of dyeability, processability and crosslinkability of a polarized light-emitting dye, and more preferably polyvinyl alcohol. Examples of polyvinyl alcohol resins or derivatives thereof include polyvinyl alcohol or derivatives thereof, polyvinyl alcohol or derivatives thereof such as ethylene, olefins such as propylene, crotonic acid, acrylic acid, methacrylic acid, and maleic acid Resin etc. which were denatured by the unsaturated carboxylic acid etc. are mentioned. Among these, in terms of the adsorptivity and orientation of the polarized light-emitting dye, the substrate is preferably a film made of polyvinyl alcohol or a derivative thereof.

Hereinafter, a method of adsorbing and orienting a polarized light emitting dye using a base material containing a polyvinyl alcohol-based resin will be exemplified. A commercial product may be used for the base material containing polyvinyl alcohol system resin, for example, and it may produce it by forming a polyvinyl alcohol system resin into a film. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and, for example, a method of melt-extruding water-containing polyvinyl alcohol, a cast film forming method, a wet film forming method, a gel film forming method After gelation, a known film-forming method such as a method of extracting and removing a solvent, a cast film-forming method (flowing a polyvinyl alcohol aqueous solution on a substrate and drying), and a combination thereof may be employed. The thickness of the substrate can be designed as appropriate, and is usually 10 to 100 μm, preferably 20 to 80 μm.

Moreover, it is preferable that a base material further contains a boron compound. In particular, the boron compound is contained so as to be substantially uniform in the thickness direction (depth direction from the surface) of the substrate, that is, the boro compound has a concentration with almost no difference between the surface and the central portion of the substrate. It is preferred that the compound is contained in the substrate. Boron compounds include, for example, inorganic compounds such as boric acid, borax, boron oxide and boron hydroxide, alkenylboronic acid which is boronic acid, arylboronic acid, alkylboronic acid, boronic acid ester, boronic acid ester, trifluoroborate or salts thereof Of these, boric acid and borax are preferred, with boric acid being particularly preferred. By containing the boron compound at a higher concentration up to the central portion with respect to the film thickness direction of the base material, the contrast of the polarized light emission of the polarized light emitting element can be further improved. Further, by containing the boron compound up to the central portion of the base material, it is possible to impart higher durability to the polarized light emitting element.

In order to make a base material contain a boron compound, it is necessary to perform the dyeing process which makes a base material contain a polarization light emitting element. This is because, even if the substrate containing the boron compound is intended to contain the polarized light-emitting dye, the dyeability of the polarized light-emitting dye is significantly inhibited since the substrate is crosslinked by the boron compound, and in the depth direction This is because the polarized light emitting dye is not impregnated. In addition, when the draw ratio of the substrate is too high, the dyeing solution is not sufficiently adsorbed to the substrate, and as a result, the polarized light emitting dye is significantly inhibited from being contained in the interior of the substrate. Therefore, it is preferable to apply the staining process before the draw ratio reaches 3.5 times the original length, more preferably before reaching 3.0 times the original length, and before reaching 2.0 times Is particularly preferred. Also, in the stage of the raw material for forming the film of the substrate, for example, in the method of forming a film of a substrate from a mixture of water, polyvinyl alcohol and a polarized light emitting pigment and stretching it, The luminescent dye may be eluted, and film thickness unevenness may occur during film formation of the substrate, and this film thickness unevenness may cause unevenness in the transmittance of the film, so it is unsuitable for mass production. It can be Therefore, at the time of including the polarized light emitting dye in the base material, the polarized light emitting dye is not contained in the film forming step of the base material, and before the step of containing the boron derivative, and The draw ratio is preferably 3.5 times or less of the original length.

As a method of confirming that the boron compound is contained in the base material, the distribution state in which the boron compound is present in the cross section of the base material may be confirmed. As a method of confirming how the boron compound is present in the cross section of the substrate, the cross section of the substrate can be confirmed by ToF-SIMS measurement. ToF-SIMS is time-of-flight secondary ion mass spectrometry and is an abbreviation of Time Of Flight Secondary Ion Mass Spectrometry. When the sample is irradiated with a primary ion beam under ultra-high vacuum, secondary ions are released from the pole surface (1 to 3 nm) of the sample. By introducing the emitted secondary ions into a time-of-flight mass spectrometer, a mass spectrum of the outermost surface of the sample can be obtained. By reducing the irradiation amount of the primary ion beam, the surface component of the sample can be detected as a molecular ion maintaining a chemical structure, a fragment that is partially cleaved, whereby the elemental composition and chemistry of the outermost surface of the sample. You can get structural information. By applying this analysis method to cross-sectional measurement of a base material, in the case of a boron compound, for example, boric acid or borax, by detecting its constituent element boron, boron oxide, boron hydroxide etc. Boron compounds in the cross section of the material, ie in the thickness direction, can be detected. As described above, the concentration distribution (content distribution) of the boron compound in the thickness direction of the substrate and the content ratio thereof can be confirmed by the ToF-SIMS measurement.

In a substrate comprising at least one or more polarized light emitting dyes and a boron compound, secondary ion intensity derived from the boron compound measured by time-of-flight secondary ion mass spectrometry in the thickness direction of the substrate on at least one side Preferably satisfies the relation of I ₂ ≦ 30 × I ₁ , more preferably satisfies the relation of I ₂ ≦ 15 × I ₁ , and still more preferably satisfies the relation of I ₂ ≦ 5 × I ₁ . In this relation, I ₁ is detected at a distance of 1/2 L from the surface of at least one side of the substrate to the maximum secondary ion intensity detected at the thickness L of the substrate 2 It represents the ratio of the secondary ion intensity. In addition, I ₂ is detected from the both surfaces of the substrate to the maximum secondary ion intensity detected at the thickness L of the substrate, respectively, up to a distance of 1⁄4 L in the thickness direction of the substrate Represents the maximum value of the ratio of secondary ion intensities. The above relationship is preferably satisfied from both surfaces of the substrate.

Further, it is preferable that the secondary ion strength derived from the boron compound further satisfy the relationship of I ₃ ≦ 5 × I ₄ , and further preferably the relationship of I ₃ ≦ 3 × I ₄ , I ₃ ≦ 1. It is particularly preferred to further satisfy the relationship of 5 × I ₄ . In this relation, I ₃ is the secondary ion intensity detected from the surface of at least one side of the substrate to the distance of 1⁄4 L with respect to the maximum secondary ion intensity detected at the thickness L of the substrate Represents the average value of the ratio of Also, I ₄ is between the center of the thickness L to the maximum secondary ion intensity detected by the thickness L of the substrate to a distance of each 1 / 4L in the thickness direction toward the both surfaces of the substrate Represents the average value of the ratio of secondary ion intensities detected in The above relationship is preferably satisfied from both surfaces of the substrate.

Furthermore, it is preferable that the secondary ionic strength derived from the boron compound further satisfy the relation of I ₅ ≦ 2 × I ₆ , and it is more preferable to further satisfy the relation of I ₅ ≦ I ₆ . In this relation, I ₅ is the secondary ion intensity detected from the surface of at least one side of the substrate to a distance of 1⁄4 L relative to the maximum secondary ion intensity detected at the thickness L of the substrate Represents the integral value of the ratio of Also, I ₆ is between the center of the thickness L to the maximum secondary ion intensity detected by the thickness L of the substrate to a distance of each 1 / 4L in the thickness direction toward the both surfaces of the substrate Represents the integral value of the ratio of secondary ion intensities detected in The above relationship is preferably satisfied from both surfaces of the substrate. In each of the above-mentioned relational expressions, “at least one surface of the substrate” means either the surface or the back of the substrate, unless the front surface or the back surface of the substrate is described. Good. For example, “secondary ion intensity detected between the surface of at least one surface of the substrate and a distance of 1⁄4 L” is detected between the surface of the front side of the substrate and a distance of 1⁄4 L. It may be any of the secondary ion intensity and the secondary ion intensity detected between the surface on the back side of the substrate and a distance of 1⁄4 L.

Thus, the degree of polarization of polarized light emission can be further improved by controlling the concentration distribution of a boron compound such as boric acid in the substrate.

In order to obtain polarized light emission having a higher degree of polarization, it is preferable that the boron compound is contained not only in the surface layer portion but also in the central portion of the substrate. Specifically, the concentration distribution of secondary ion intensity derived from the boron compound is preferably present at least between 3 μm and 20 μm from the surface of the substrate, and is present at a depth of at least 5 μm from the surface of the substrate Is more preferably present to a depth of at least 8 μm, and particularly preferred to be at a depth of at least 10 μm. More preferably, the relationship is satisfied from both surfaces of the substrate.

In addition, it can also be confirmed to what extent the thickness of the substrate of the polarized light emitting dye is contained. Raman analysis is mentioned as this method. When a substance is irradiated with light, light scattering occurs, and in the scattered light, light of the same wavelength as the incident light is scattered (elastic scattering), and Raman is scattered by the molecular vibration to a wavelength different from the incident light There is scattering (inelastic scattering). A method of analyzing the structure of molecular level from the obtained Raman spectrum by dispersing the Raman light is Raman spectroscopy. By applying the micro-Raman spectrophotometer, the energy in the thickness direction of the substrate can be sensed on the order of micrometers, so that the thickness of the substrate containing the polarized light emitting dye can be accurately confirmed. As described above, by applying Raman spectroscopy while scanning in the thickness direction with respect to the cross section of the base material, it is possible to measure the extent to which the polarized light emitting dye is contained in the base material. Specifically, in the case of the stilbene compound described above, for example, the compound described in Compound Example 5-1, energy based on each of 1170 to 1180 cm ^-1 and 1560 to 1600 cm ^-1 can be detected. Then, Raman spectroscopy is applied while scanning the detected energy in the thickness direction with respect to the cross section of the substrate. By such a method, it can be confirmed to what extent of the thickness of the substrate the polarized light emitting dye is contained.

<Method of manufacturing polarized light emitting element>
The method for producing a polarized light emitting device is not limited to the following production method, but it is preferable to mainly orient the above-mentioned polarized light emitting dye in a film using polyvinyl alcohol or a derivative thereof. Hereinafter, a method of manufacturing a polarized light emitting device will be described by taking polyvinyl alcohol or a derivative thereof as an example.

The method for producing a polarized light emitting device comprises the steps of preparing a substrate, swelling the substrate by immersing the substrate in a swelling solution, and swelling the substrate, and one of the polarized light emitting dyes mentioned above. A dyeing step of impregnating a dye solution containing at least the above with a dye solution for adsorbing a polarized light-emitting dye, and immersing a substrate with the polarized light-emitting dye adsorbed thereon in a solution containing boric acid The step of crosslinking in the material, the step of uniaxially stretching the base material obtained by crosslinking the polarized light-emitting dye in a fixed direction, and arranging the polarized light-emitting dye in a fixed direction, and, if necessary, the stretched group Washing the material with a washing solution and / or drying the washed substrate.

(Swelling process)
The swelling step is preferably performed by immersing the above-mentioned substrate in a swelling solution at 20 to 50 ° C. for 30 seconds to 10 minutes, and the swelling solution is preferably water. The draw ratio of the substrate by the swelling solution is preferably adjusted to 1.00 to 1.50 times, and more preferably adjusted to 1.10 to 1.35 times.

(Staining process)
At least one polarized light emitting dye is impregnated and adsorbed onto the substrate obtained by the swelling treatment in the swelling step. The dyeing process is not particularly limited as long as it is a method of impregnating and adsorbing a polarized light emitting dye to a substrate, but for example, a method of immersing a substrate in a dyeing solution containing a polarized light emitting dye, the substrate The method of apply | coating and adsorb | sucking a dyeing | staining solution etc. are mentioned. Among these, the method of immersing in a staining solution containing a polarized light emitting dye is preferred. The concentration of the polarized light emitting dye in the staining solution is not particularly limited as long as the polarized light emitting dye is sufficiently adsorbed in the substrate, and for example, it is 0.0001 to 1% by mass in the staining solution Is preferable, and 0.001 to 0.5% by mass is more preferable.

The temperature of the dyeing solution in the dyeing step is preferably 5 to 80 ° C., more preferably 20 to 50 ° C., particularly preferably 40 to 50 ° C. The time to immerse the substrate in the staining solution is important when controlling the value of the order parameter. In order to control the value of the order parameter indicated by the polarized light emitting element within the desired range, the time for immersing the substrate in the staining solution is preferably adjusted between 6 and 20 minutes, preferably between 7 and 10 minutes. More preferable.

The polarized light emitting dyes contained in the staining solution may be used alone or in combination of two or more. The light emission color of the above-mentioned polarized light emitting dye differs depending on the compound, and therefore, by containing one or more kinds of the above polarized light emitting dye in the base material, it is possible to appropriately adjust the emitted light color to be various colors. In addition, as necessary, the staining solution may further contain one or more organic dyes and / or fluorescent dyes different from the polarized light emitting dye.

When a fluorescent dye and / or an organic dye are used in combination, it is possible to select the dye to be blended and adjust the blending ratio etc. for the desired color adjustment of the polarizing element. Although the blending ratio of the fluorescent dye or the organic dye is not particularly limited depending on the preparation purpose, generally, the total amount of the fluorescent dye and / or the organic dye is 0.01 relative to 100 parts by mass of the polarizing element. It is preferable to use in the range of ̃10 parts by mass.

Further, in addition to the above-described dyes, if necessary, a dyeing assistant may be further used in combination. Examples of the dyeing assistant include sodium carbonate, sodium hydrogencarbonate, sodium chloride, sodium sulfate (sodium sulfate), anhydrous sodium sulfate, sodium tripolyphosphate and the like, with preference given to sodium sulfate. The content of the dyeing assistant can be optionally adjusted by the above-mentioned immersion time, temperature at the time of dyeing, etc. based on the dyeability of the dichroic dye to be used, but in 0.0001 to 10% by mass in the dyeing solution Is preferable, and more preferably 0.0001 to 2% by mass.

After the above-mentioned dyeing process, in order to remove the dyeing solution adhering to the surface of the substrate in the dyeing process concerned, a preliminary washing process can be optionally performed. By carrying out the preliminary washing step, it is possible to suppress migration of the polarized luminescent dye remaining on the surface of the substrate in the solution to be treated next. In the preliminary washing step, water is generally used as the washing solution. The washing method is preferably to immerse the dyed substrate in the washing solution, while washing can also be carried out by applying the washing solution to the substrate. The washing time is not particularly limited, but is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds. The temperature of the cleaning solution in this preliminary cleaning step needs to be a temperature at which the material constituting the substrate does not dissolve, and the cleaning process is generally performed at 5 to 40.degree. In addition, even if there is no step of the pre-cleaning step, the pre-cleaning step can be omitted because the performance of the polarizing element is not particularly affected.

(Crosslinking step)
The crosslinker can be contained in the substrate after the dyeing step or the pre-cleaning step. It is preferable to immerse a base material in the processing solution containing a crosslinking agent as a method of making a base material contain a crosslinking agent, and on the other hand, you may apply | coat or apply the said processing solution to a base material. As the crosslinking agent in the treatment solution, for example, a solution containing a boron compound is used. Boron compounds include, for example, inorganic compounds such as boric acid, borax, boron oxide and boron hydroxide, alkenylboronic acid which is boronic acid, arylboronic acid, alkylboronic acid, boronic acid ester, boronic acid ester, trifluoroborate or salts thereof Of these, boric acid and borax are preferred, with boric acid being particularly preferred. Although the solvent in the treatment solution is not particularly limited, water is preferred. The concentration of the boron derivative in the treatment solution is preferably 0.1 to 15% by mass, and more preferably 0.1 to 10% by mass. The temperature of the treatment solution is preferably 30 to 80 ° C., and more preferably 40 to 75 ° C. In addition, the treatment time of this crosslinking step is preferably 30 seconds to 10 minutes, and more preferably 1 to 6 minutes. The polarized light emitting element obtained by this crosslinking step exhibits high contrast. This is a completely unexpected effect from the function of the boron compound used in the prior art for the purpose of improving water resistance or light transmission. In addition, in the crosslinking step, if necessary, the fix treatment may be additionally performed with an aqueous solution containing a cation or a cationic polymer compound. The cation is an ion derived from a metal such as sodium, potassium, calcium, magnesium, aluminum, iron, barium and the like, and preferably a divalent ion is used. Specifically, calcium chloride, magnesium chloride, iron chloride, barium chloride and the like. Fixing allows the immobilization of the polarized luminescent dye in the substrate. At this time, as a cationic polymer compound, for example, dicyanamide as a dicyanamide and formalin polymerization condensate, polycyanate as a dicyandiamide • diethylenetriamine polycondensate, polycation as an epichlorohydrin • dimethylamine addition polymer, dimethyldiallylammonate A sodium chloride / dioxide ion copolymer, a diallylamine salt polymer, a dimethyldiallyl ammonium chloride polymer, a polymer of allylamine salt, a dialkylaminoethyl acrylate quaternary salt polymer or the like is used.

(Stretching process)
After carrying out the above crosslinking step, the stretching step is carried out. The stretching step is performed by uniaxially stretching the substrate in a fixed direction. The stretching method may be either a wet stretching method or a dry stretching method. The draw ratio of the substrate is also important in controlling the value of the order parameter. In order to control the value of the order parameter indicated by the polarized light emitting element within a desired range, the stretching ratio of the substrate is preferably 3.3 times or more, more preferably 3.3 to 8.0 times It is more preferably 3.5 to 6.0 times, particularly preferably 4.0 to 5.0 times.

In the wet stretching method, the substrate is preferably stretched in water, a water-soluble organic solvent or a mixed solution thereof. More preferably, the stretching treatment is performed while immersing the substrate in a solution containing at least one crosslinking agent. As the crosslinking agent, for example, the boron compound in the above crosslinking agent step can be used, and preferably, the stretching treatment can be performed in the treatment solution used in the crosslinking step. The stretching temperature is preferably 40 to 60 ° C., and more preferably 45 to 58 ° C. The stretching time is usually 30 seconds to 20 minutes, preferably 2 to 7 minutes. The wet drawing process may be carried out by one-step drawing or by two or more multi-step drawing. The stretching treatment may optionally be carried out before the dyeing step, in which case the orientation of the polarized luminescent dye can be carried out together at the time of dyeing.

In the above-mentioned dry stretching method, when the stretching heating medium is an air medium, it is preferable to stretch the substrate at a temperature of the air medium of from normal temperature to 180 ° C. The humidity is preferably in an atmosphere of 20 to 95% RH. Examples of the method for heating the substrate include, but are not limited to, a roll-to-roll zone drawing method, a roll heating drawing method, a hot pressure drawing method, an infrared heating drawing method, and the like. The dry stretching step may be carried out in one step of stretching or in two or more steps of multi-step stretching. In the dry stretching step, the substrate containing a polarized light emitting dye can be stretched while containing a boron derivative, or the boron compound can be stretched after being contained in a substrate, but the boron compound is contained in the substrate It is preferable to carry out a stretching treatment after the treatment. The temperature at which the boron derivative is applied is preferably 40 to 90 ° C., more preferably 50 to 75 ° C. The concentration of the boron compound is preferably 1 to 10%, more preferably 3 to 8%. The processing time for dry stretching is preferably 1 to 15 minutes, more preferably 2 to 12 minutes, and still more preferably 3 to 10 minutes.

(Washing process)
After the stretching step is carried out, since the deposition of the crosslinking agent or foreign substances may adhere to the surface of the substrate, a cleaning step of cleaning the surface of the substrate can be performed. The washing time is preferably 1 second to 5 minutes. The cleaning method preferably immerses the substrate in the cleaning solution, while the cleaning solution can also be cleaned by coating or coating on the substrate. Water is preferred as the cleaning solution. The washing treatment may be carried out in one step, or may be carried out in two or more steps. The temperature of the washing solution in the washing step is not particularly limited, but is usually 5 to 50 ° C., preferably 10 to 40 ° C., and may be normal temperature.

As a solvent for the solution or treatment liquid used in each of the above steps, other than the above water, for example, dimethyl sulfoxide, N-methyl pyrrolidone, methanol, ethanol, propanol, isopropyl alcohol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, Examples thereof include alcohols such as triethylene glycol, tetraethylene glycol or trimethylolpropane, and amines such as ethylene diamine and diethylene triamine. The solvent of the solution or treatment solution is, but not limited to, most preferably water. Moreover, the solvent of these solutions or a process liquid may be used individually by 1 type, and 2 or more types may be mixed and used.

(Drying process)
After the washing step, the substrate is dried. Although the drying process can be performed by natural drying, it can be performed by compression with a roll or removal of water on the surface by an air knife, a water absorption roll, etc., in order to further increase the drying efficiency. It is also possible to do. The temperature of the drying treatment is preferably 20 to 100 ° C., and more preferably 60 to 100 ° C. The drying time is preferably 30 seconds to 20 minutes, and more preferably 5 to 10 minutes.

The polarized light emitting device according to the present invention can be manufactured by the above-described manufacturing method, and the obtained polarized light emitting device has high durability and exhibits polarized light emission having a high degree of polarization (contrast).

The polarized light emitting element exhibits polarized light emission in the visible light region using energy obtained by light absorption, particularly absorption of light in the ultraviolet light region. In order to further improve the lightness difference of this polarized light emission, it is preferable that the polarized light emission has a high degree of polarization (contrast). Since the light emitted from the polarized light emitting element is polarized light in the visible light range, when the polarized light emitting element is observed through a general polarizing plate having a polarizing function with respect to light in the visible light range, By changing the angle of the axis, it is possible to view polarized light emission and non-emission light. The polarization degree of the polarized light emitted by the polarized light emitting element is, for example, 70% or more, preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, and particularly preferably 99% or more. The higher the contrast, the better, and the higher the degree of polarization, the higher the tendency. When the polarized light emitting element transmits light in the visible light range without absorption, the light transmittance of the polarized light emitting element in the visible light range is, for example, 60% or more, preferably 70 %, More preferably 80% or more, still more preferably 85% or more, particularly preferably 90% or more. Since such a polarized light emitting element has a high degree of polarization, the absorption in the visible light range becomes small in the non-emitting state, whereby a polarized light emitting element with high transparency can be obtained. In addition, a high degree of polarization of polarized light emission by the polarized light emitting element is important because a bright display with high contrast can be realized, and it is also important that the transmittance of light in the visible light range is high. It is effective as a new transparent liquid crystal display.

<Visible light absorbing dye containing layer>
The polarized light emitting element preferably further includes a visible light absorbing dye-containing layer on at least one surface of the polarized light emitting element as a layer that absorbs polarized light. As a result, it is possible to obtain a polarized light emitting element having a large difference between the contrast of polarized light emission, that is, the intensity of light of the strong axis of light emission and the intensity of light of the weak axis of light emission in polarized light.

The method for further forming a visible light absorbing type dye-containing layer on a polarized light emitting element is not particularly limited, but a polarized light emitting element absorbs a light in the visible light region and does not exhibit a light emitting function. It is preferable to provide the containing layer. In such a visible light absorbing dye-containing layer, the visible light absorbing dye is directly applied to the surface of the polarized light emitting dye, or the visible light absorbing dye is contained only on the surface of the polarized light emitting element, or visible light absorbing When a resin layer containing a dye is formed on a polarized light emitting element, or when a transparent protective layer to be described later is formed on a polarized light emitting element, a transparent protective layer can be obtained by using an adhesive layer containing a visible light absorbing dye. A visible light absorbing dye-containing layer is formed in the polarized light emitting device by forming a visible light absorbing dye-containing layer with the polarized light emitting device, or by including a visible light absorbing dye in the transparent protective layer. be able to. The direction of absorption of polarized light emitted by the visible light absorbing dye-containing layer is not necessarily limited as to whether it has light absorption anisotropy, but the visible light absorbing dye-containing layer has light absorption anisotropy Preferably, the absorption direction of light based on the light absorption anisotropy is orthogonal to the polarized light emission by the polarized light emitting element. Thereby, light in a direction orthogonal to the polarization axis (emission axis) of polarized light emission from the polarized light emitting element can be strongly absorbed, and as a result, polarized light emission having a higher degree of polarization (contrast) can be obtained. The visible light absorbing dye-containing layer may be provided on the surface layer of the polarized light emitting element, may be provided only on one side of the polarized light emitting element, or may be laminated on both sides of the polarized light emitting element .

The visible light absorbing dye is a dye having a low fluorescence quantum yield (φ) and which can not confirm light emission such as fluorescence or phosphorescence visually when absorbing light. The fluorescence quantum yield is the ratio of the number of photons absorbed to the number of photons emitted (number of photons emitted / number of photons absorbed), and the higher the fluorescence quantum yield, the better the emission. It is recognized as a pigment. That is, as the fluorescence quantum yield approaches 1 it may be recognized as a better light emitting dye, but the visible light absorbing dye is not particularly limited as long as its fluorescence quantum yield is low. Specifically, in a display medium such as a display, it is preferable that the light emission can not be visually confirmed through the visible light absorbing dye-containing layer.

The emission intensity (F) of the visible light absorbing dye is generally represented by the following formula (IV). In formula (IV), Ι ₀ represents the intensity of light (excitation light) irradiated to the visible light absorbing dye, and ε represents the absorption intensity of the visible light absorbing dye for light of a certain wavelength, ie, Represents molecular absorption efficiency, φ represents the above-mentioned fluorescence quantum yield, and C represents the molar concentration of the visible light absorbing dye. The light emitted to the visible light absorbing dye varies depending on the environment in which the display medium is used and the irradiation device, and the light emission intensity (F) is also the molecular absorption efficiency (ε) of the visible light absorbing dye and the concentration ( It also fluctuates according to C). Therefore, it is difficult to limit the preferred visible light absorbing dye to be applied to the display medium only with the fluorescence quantum yield (φ) of the visible light absorbing dye. From such a point of view, the visible light absorbing dye may be a dye which can not confirm the light emission from the polarized light emitting element visually, and for example, a dye having a fluorescence quantum yield (φ) of 0.1 or less is used The fluorescence quantum yield (φ) is preferably 0.01 or less, more preferably 0.001 or less.

Luminescence intensity (F) = Ι ₀ × ε × φ × C (IV)

It is preferable that the absorption wavelength of the visible light absorbing dye can absorb only the light of the emission wavelength of the polarized light emitting dye used for the polarized light emitting element, while the absorption of the visible light absorbing dye at the absorption wavelength of the polarized light emitting dye It is more preferable that there is little or no. Thereby, the contrast in polarized light emission of the polarized light emitting element can be improved, and the absorption efficiency of the polarized light emitting dye can be further improved.

The visible light transmittance of the visible light absorbing dye-containing layer is not particularly limited, but the light emission of the layer interface of the polarized light emitting element, in particular, the interface of the surface layer is suppressed by the visible light absorbing dye. The contrast in polarized light emission of the device is improved. The visible light absorbing dye-containing layer absorbs visible light to an extent not affected by the measurement of visible light transmittance, and can exhibit the above effects even when the reduction rate (loss) of visible light transmittance is 0%. is there. For example, when the visible light transmittance of the polarized light emitting element is 90% or more, the visible light transmittance of the visible light absorbing dye-containing layer is 0 to 50%, so that the visible light transmittance of general polarizing plate or more Can be realized. Therefore, if the reduction rate of the visible light transmittance by the visible light absorbing dye-containing layer is 50% or less, the contrast exhibited by the polarized light emission from the polarized light emitting element can be improved, and thus the polarized light capable of exhibiting the polarization function It is useful as a light emitting element. Moreover, unlike a general polarizing plate, since it can also be used as a light emission type polarizing functional film, it can be used in various fields. As the visible light transmittance of the visible light absorbing dye-containing layer is higher by absorbing polarized light more, the visible light transmittance of the polarized light emitting device is improved. Therefore, the reduction rate (loss) of the visible light transmittance by the visible light absorbing dye-containing layer is preferably 50% or less, more preferably 0 to 30%, still more preferably 0 to 20%, and 0 to 10%. Particularly preferred. By setting the reduction rate of the visible light transmittance to 0 to 10%, it is possible to maintain high transmittance while improving the contrast of polarized light emission.

[Polarized light emitting plate]
A polarized light emitting plate according to the present invention comprises the above-described polarized light emitting element, and a transparent protective layer provided on one side or both sides of the polarized light emitting element. Such a transparent protective layer is used to improve the water resistance, the handleability and the like of the polarized light emitting element. Therefore, such a transparent protective layer does not have any influence on the polarization action of the polarized light emitting device according to the present invention. However, when the polarized light emitting element absorbs light in the ultraviolet light range to exhibit polarized light emission, the transparent protective layer preferably does not have an ultraviolet light absorbing function, and in particular, a plastic film not having an ultraviolet light absorbing function Is preferred.

The transparent protective layer is preferably a transparent protective film excellent in optical transparency and mechanical strength. Further, the transparent protective layer is preferably a film having a layer shape capable of maintaining the shape of the polarized light emitting element, and is a plastic film which is excellent in thermal stability, moisture shielding property, etc. in addition to transparency and mechanical strength. Is preferred. As a material for forming such a protective film, for example, a cellulose acetate film, an acrylic film, a fluorine film such as tetrafluoroethylene / hexafluoropropylene copolymer, a polyester resin, a polyolefin resin Alternatively, a film made of a polyamide-based resin may, for example, be mentioned. Preferably, a triacetyl cellulose (TAC) film or a cycloolefin-based film is used. The thickness of the transparent protective layer is preferably in the range of 1 μm to 200 μm, more preferably in the range of 10 μm to 150 μm, and particularly preferably 40 μm to 100 μm. The method for producing a polarized light emitting plate is not particularly limited. For example, a polarized light emitting plate can be produced by laminating a transparent protective layer on a polarized light emitting element and laminating it according to a known formulation.

The polarized light emitting plate may further include, between the transparent protective layer and the polarized light emitting element, an adhesive layer for bonding the transparent protective layer to the polarized light emitting element. The adhesive constituting the adhesive layer is not particularly limited, and polyvinyl alcohol adhesives, urethane emulsion adhesives, acrylic adhesives, polyester-isocyanate adhesives, etc. may be mentioned, with preference given to polyvinyl An alcohol adhesive is used. After bonding the transparent protective layer and the polarized light emitting element with an adhesive, the polarized light emitting plate can be produced by drying or heat treatment at an appropriate temperature.

In addition, the polarized light emitting plate may be appropriately provided with known various functional layers such as an antireflection layer, an antiglare layer, and a further transparent protective layer on the exposed surface of the transparent protective layer. When producing layers having such various functionalities, it is preferable to apply a material having various functionalities to the exposed surface of the transparent protective layer, and on the other hand, a layer or film having such a function as an adhesive or It is also possible to bond to the exposed surface of the transparent protective layer via an adhesive.

As a further transparent protective layer, hard coat layers, such as an acryl type and a polysiloxane type, a urethane type protective layer etc. are mentioned, for example. Moreover, in order to improve single-piece | unit transmittance | permeability further, an anti-reflective layer can also be provided on exposure of a transparent protective layer. The antireflective layer can be formed, for example, by vapor deposition or sputtering of a substance such as silicon dioxide or titanium oxide on the transparent protective layer, or thinly coating a fluorine-based substance on the transparent protective layer.

The polarized light-emitting plate according to the present invention may further include a support layer, if necessary. As the support layer, for example, a transparent support such as glass, quartz, sapphire or the like can be further provided. Such a support preferably has a flat portion to be attached to a polarized light emitting plate, and is preferably a transparent substrate from the viewpoint of optical use. The transparent substrate is divided into an inorganic substrate and an organic substrate. Examples of the inorganic substrate include soda glass, borosilicate glass, quartz substrate, sapphire substrate, spinel substrate and the like, and organic substrates are acrylic, polycarbonate, etc. Examples include substrates made of polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer and the like. The thickness and size of the transparent substrate are not particularly limited, and can be determined as appropriate. In addition, in the polarized light emitting plate having such a transparent substrate, in order to further improve the single transmittance, it is preferable to provide an antireflection layer on one or both of the support surface or the polarized light emitting plate surface. In order to bond the polarized light emitting plate to the flat surface of the support, a transparent adhesive (adhesive) agent may be applied to the flat surface of the support, and then the polarized light emitting plate according to the present invention may be attached to this coated surface. . The adhesive or pressure-sensitive adhesive to be used is not particularly limited, and a commercially available one may be used, and an acrylic ester-based adhesive or pressure-sensitive adhesive is preferable.

The polarizing plate according to the present invention can also be used as an element or a circularly polarized light emitting plate that emits circularly polarized light, or an element that emits elliptically polarized light, or an elliptically polarized light emitting plate by attaching a retardation plate. When a support or the like is further provided on the polarized light emitting plate, the support may be provided on the side of the retardation plate or on the side of the polarized light emitting plate. Thus, the polarized light emitting plate can be further provided with various functional layers, supports, etc. Such a polarized light emitting plate is, for example, a liquid crystal projector, a calculator, a watch, a notebook computer, a word processor, a liquid crystal television, It can be used for various products such as car navigation and indoor / outdoor measuring instruments and displays, lenses, or glasses.

The polarized light emitting element and the polarized light emitting plate according to the present invention exhibit a high degree of polarization in the ultraviolet light region, and further exhibit polarized light emitting action and high transmittance in the visible light region. In addition, since the polarized light emitting element and the polarized light emitting plate according to the present invention show excellent durability against heat, humidity, light and the like, their performance can be maintained even under severe environments, It has higher durability than iodine-based polarizers. Therefore, the polarized light emitting element and the polarized light emitting plate according to the present invention are liquid crystal displays which are required to have high transparency in the visible light region and high durability under severe environments, such as television, wearable terminal, tablet terminal, smartphone The present invention can be applied to various display devices such as in-vehicle monitors, digital signage used outdoors or indoors, and smart windows.

[Display device]
The display device according to the present invention includes the polarized light emitting element or the polarized light emitting plate in the present invention. Therefore, such a display device can form a display capable of displaying an image while emitting light by being irradiated with light of a specific wavelength. For example, the surface of a substrate that absorbs only a specific wavelength, ie has a specific color, can emit polarized light of different color wavelengths. Furthermore, by emitting light of 400 nm or less, for example, ultraviolet light, a polarized light emitting action is shown in the visible light region, and by using this action, an image can be displayed on the display. As described above, by combining the above-mentioned polarized light emitting element or polarized light emitting plate with the liquid crystal display, it can be used as a self-luminous liquid crystal display unlike a conventional liquid crystal display using a general polarizing plate. In the display device, when the visible light absorbing dye-containing layer is further provided on at least one surface of the polarized light emitting element, the visible light absorbing dye-containing layer is provided at least on the viewer side. Is preferred. By arranging the visible light absorbing dye-containing layer on the viewer side, it is possible to improve the contrast of high contrast to the viewer.

Since the display device according to the present invention has high transmittance in the visible light region, there is no decrease in transmittance in the visible light region as in the conventional polarizing plate, or even if there is a decrease in transmittance, The decrease in transmittance is significantly less than that of the conventional polarizing plate. For example, in the iodine based polarizing plate, which is a conventional polarizing plate, and the dye based polarizing plate using other dye compounds, in order to make the degree of polarization approximately 100%, the visibility correction in the visible light region is 35 to 43 It needs to be around%. The reason is that the conventional polarizing plate has both the vertical axis and the horizontal axis as an absorption axis of light, but one of the vertical axis or the horizontal axis is incident to obtain a degree of polarization of approximately 100%. By absorbing light, ie by absorbing light in one axis and transmitting light in the other axis, polarization occurs. In such a case, the light in one axis is absorbed and does not transmit, so the transmissivity necessarily becomes 50% or less. Moreover, although the conventional polarizing plate orientates a dichroic dye in a stretched film to produce a polarizing plate, the dichroic dye is not necessarily 100% oriented, and light It also has a light absorbing action on the transmission axis of Therefore, the degree of polarization of 100% can not be realized unless the transmittance is about 43% or less due to the surface reflection of the substance, that is, the degree of polarization can not be realized unless the transmittance is reduced. On the other hand, when the polarized light emitting element or the polarized light emitting plate according to the present invention absorbs light in the ultraviolet light range, the light absorption axis is about 400 nm or less. In this case, the polarized light emitting element or the polarized light emitting plate exhibits a polarized light emitting action of emitting light polarized in the visible light region, but hardly absorbs light in the visible light region, so the transmittance in the visible light region is very high. Get higher. Furthermore, in the visible light region, since it exhibits a polarized light emitting action, the loss of light is smaller than in the case of using a conventional polarizing plate, that is, the decrease in transmittance as in the conventional polarizing plate is very small. From this, a display using the polarized light emitting element or the polarized light emitting plate according to the present invention, for example, a liquid crystal display can obtain higher luminance than a liquid crystal display using a conventional polarizing plate. Furthermore, since the display device including the polarized light emitting element or the polarized light emitting plate according to the present invention has high transparency, it is possible to obtain a display that is very nearly transparent, although it is a liquid crystal display. In addition, since it can be designed to transmit polarized light when displaying characters and images, it is possible to obtain a display that can be displayed even though it is a transparent liquid crystal display, that is, a display that can display characters and the like on a transparent display. Be Therefore, the display device according to the present invention is effective for application as a transparent liquid crystal display without light loss, particularly as a see-through display.

On the other hand, since the display device according to the present invention can be polarized by, for example, ultraviolet light invisible to human eyes, it can be applied to a liquid crystal display capable of displaying by ultraviolet light. By recognizing an image or the like displayed in the ultraviolet light region with a computer or the like, it is possible to manufacture a simple and highly secure liquid crystal display that can be viewed only when irradiated with ultraviolet light.

The display device according to the present invention exhibits, for example, a polarized light emitting action by irradiating ultraviolet light, and a liquid crystal display using the polarized light emission can be manufactured. Therefore, it is also possible to realize a liquid crystal display using ultraviolet light, not a normal liquid crystal display using visible light. That is, even in a dark space where there is no light, if it is a space that can be irradiated with ultraviolet light, it is possible to fabricate a self-luminous liquid crystal display in which displayed characters, images, and the like are displayed.

Furthermore, since the absorption band of light is different between the visible light region and the ultraviolet light region, the visible light region is a liquid crystal display portion that can be displayed by the light in the visible light region and the light displayed by the polarized light emitting action by the ultraviolet light. It is also possible to produce a display capable of two different displays in which the liquid crystal display portion coexists. Although two displays capable of different displays exist to date, there are no displays capable of different displays by different light sources in the ultraviolet light region and the visible light region although they are the same liquid crystal panel . From this, the display device according to the present invention can produce a novel display by having the above-mentioned polarized light emitting element or polarized light emitting plate.

The display device according to the present invention may be a liquid crystal display for on-vehicle use or outdoor display. The liquid crystal cell to be used is not limited to, for example, TN liquid crystal, STN liquid crystal, VA liquid crystal, IPS liquid crystal, etc. in a liquid crystal display for vehicle or outdoor display, and the liquid crystal display can be used in all liquid crystal display modes. It is possible. The polarized light emitting element according to the present invention is excellent in polarization performance and further suppresses discoloration and deterioration in polarization performance even in a car or outdoors under high temperature and high humidity, thus improving the long-term reliability of the liquid crystal display for vehicle or outdoor display Can contribute to

Hereinafter, the present invention will be described in more detail by way of examples, but these are illustrative and do not limit the present invention at all. The “%” and “parts” described below are on a mass basis unless otherwise stated. In addition, in each structural formula of the compound used by each Example and comparative example, acidic functional groups, such as a sulfo group, were described in the form of a free acid.

[Evaluation method]
Evaluation using the polarized light emitting elements or the polarized light emitting plates obtained in the following Examples and Comparative Examples as measurement samples was performed as follows.

(A) Order parameter (OPD)
The value of the order parameter of the polarized light emitting device was evaluated using a spectrophotometer ("U-4100" manufactured by Hitachi High-Technologies Corporation). Each polarized light emitting element (measurement sample) manufactured in each example and comparative example is absolutely irradiated with light (hereinafter referred to as “absolutely polarized light”) having approximately 100% polarized light in a wavelength range of 220 nm to 2600 nm A polarization gram tailor prism was installed, and the transmittance of light of each wavelength was measured when each measurement sample was irradiated with absolute polarization. The light transmittance measured when light polarized orthogonally to the axis showing absorption of the highest light in a polarized light emitting element irradiated with absolute polarized light and oriented with a polarized light emitting dye is Ky, absolute polarized light And the light transmittance measured when light polarized parallel to the axis showing absorption of the highest light in the polarized light emitting element in which the polarized light emitting dye is oriented is Kz, the respective values Were substituted into the following formula (I). The obtained value was evaluated as the value of the order parameter (OPD) of the polarized light emitting element.

(B) Visibility correction single transmittance Ys
The visual sensitivity correction single transmittance Ys of each measurement sample is substituted for the above-mentioned Ky and Kz obtained for each predetermined wavelength interval dλ (here, 5 nm) in the wavelength range of 400 to 700 nm in the visible light region. Then, the single transmittance Ts of each wavelength is calculated, and the transmittance is corrected to the visibility according to JIS Z 8722: 2009. Specifically, the single transmittance Ts was substituted into the following formula (VI) to calculate. In the following formula (VI), Pλ represents the spectral distribution of standard light (C light source), and yλ represents a two-degree visual field color matching function.

Ts = (Ky + Kz) / 2 (V)

(C) Degree of polarization ρ
The degree of polarization ρ of each measurement sample was determined by substituting the parallel transmittance Tp and the orthogonal transmittance Tc into the following equation (VII). Here, the parallel transmittance Tp was measured using a spectrophotometer ("U-4100" manufactured by Hitachi High-Technologies Corporation), by superposing two measurement samples so that the absorption axis direction is parallel. It is the spectral transmittance of each wavelength. Further, the orthogonal position transmittance Tc is a spectral transmittance measured by superposing two polarizing plates with their absorption axes orthogonal to each other using a spectrophotometer. The measurements were taken over a wavelength of 220-780 nm.

ρ = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100 (VII)

(D) Polarized light emission contrast As a light source, a 395 nm hand light type LED black light ("FBA_VS-FL01 JP (ASIN: B01 EAJB9BA)" manufactured by Vansky JAPAN) is used. The company made "IUV-340" to cut visible light. Furthermore, a polarizing plate having a polarizing function with respect to light in the visible light region and the ultraviolet light region (“SKN-18043P” manufactured by Polatechno, thickness 180 μm, Ys 43%) or less “referred to as“ measuring polarizing plate ” And the polarized light emitting plate obtained in each of the examples and the comparative examples, and the polarized light emitted by the polarized light emitting plate is measured using a spectral radiance meter (“USR-40” manufactured by USHIO INC.) It was measured. That is, the light from the light source passes through the ultraviolet light transmitting / visible cut filter, the measurement polarizing plate and each polarized light emitting plate in this order, and the polarized light from each polarized light emitting plate enters the spectral irradiometer. Measured. At that time, Lw is the spectral light emission amount of each wavelength measured by superposing the absorption axis at which absorption of light in the ultraviolet light region of each polarized light emitting plate is maximum with the absorption axis of the polarizing plate for measurement parallel. (Weak emission axis), the amount of spectral emission of each wavelength measured by superposing the absorption axis at which absorption of light in the ultraviolet light range of each polarized light emission plate is maximum with the absorption axis of the polarizing plate for measurement orthogonally Lw and Ls were measured by setting Ls as Ls (strong light emission axis). Check the amount of energy of light emitted in the visible light range when the absorption axis of each polarized light emitting plate is parallel to the absorption axis of the measurement polarizing plate, and when it is orthogonal to each other. Polarized light emission was evaluated in the visible light range of 400 nm to 700 nm by using the value of the contrast (ECR).

<Synthesis of polarized light emitting dye>
Synthesis Example 1
35.2 parts of commercially available 4-amino-4'-nitrostilbene-2,2'-disulfonic acid was added to 300 parts of water and stirred, and the pH was adjusted to 0.5 using 35% hydrochloric acid. 10.9 parts of 40% aqueous sodium nitrite solution is added to the obtained solution, and the mixture is stirred at 10 ° C. for 1 hour, and then 17.2 parts of 6-aminonaphthalene-2-sulfonic acid is added, and a 15% aqueous sodium carbonate solution is used. After adjusting to pH 4.0, the mixture was stirred for 4 hours. 60 parts of sodium chloride is added to the obtained reaction liquid, and the precipitated solid is separated by filtration and further washed with 100 parts of acetone to obtain 124.0 parts of a wet cake of a compound of the following formula (6) as an intermediate. The

The obtained intermediate (62.3 parts of the formula (6)) was added to 300 parts of water and stirred, and the pH was adjusted to 10.0 using a 25% aqueous sodium hydroxide solution. Twenty parts of 28% aqueous ammonia and 9.0 parts of copper sulfate pentahydrate were added to the obtained solution, and the mixture was stirred at 90 ° C. for 2 hours. To the resulting reaction solution, 25 parts of sodium chloride was added, and the precipitated solid was separated by filtration and further washed with 100 parts of acetone to obtain 40.0 parts of a wet cake of a compound of the formula (7). The wet cake was dried with a hot air dryer at 80 ° C. to obtain 20.0 parts of a compound (λmax: 376 nm) of the following formula (7).

(Composition example 2)
A commercially available sodium 4,4'-diaminostilbene-2,2'-disulfonate 41.4 parts was added to 300 parts of water at 10 ° C in the presence of sodium carbonate and stirred. Further, 34.0 parts of a compound represented by the formula (8) is added and reacted at pH 10, 60 parts of sodium chloride is added to the obtained reaction solution, and the precipitated solid is separated by filtration and further washed with 100 parts of acetone. As a result, 68.4 parts of a wet cake of a compound of the formula (9) was obtained. The wet cake was dried by a hot air drier at 80 ° C. to obtain 33 parts of a compound (λmax: 356 nm) of the following formula (9).

(Composition example 3)
6.0 parts of a compound of the following formula (10) synthesized by the method described in WO 2005/033211 and 1.6 parts of potassium carbonate were added to 50 parts of N-methyl-2-pyrrolidone and stirred. To the resulting solution was added 2.1 parts of 4-methoxybenzoyl chloride, and the mixture was stirred at 90 ° C. for 4 hours. The obtained reaction solution was added to 300 parts of a 20% aqueous sodium chloride solution, and the precipitated solid was separated by filtration and further washed with 100 parts of acetone to obtain 20.0 parts of a wet cake of a compound of the formula (11). The wet cake was dried with a hot air drier at 80 ° C. to obtain 5.0 parts of a compound of the following formula (11) (λmax: 372 nm).

(Composition example 4)
A commercially available sodium 4,4'-diaminostilbene-2,2'-disulfonate 41.4 parts was added to 300 parts of water and stirred, and the pH was adjusted to 0.5 using 35% hydrochloric acid. 10.9 parts of 40% aqueous sodium nitrite solution is added to the obtained solution and stirred at 10 ° C. for 1 hour, and then 34.4 parts of 6-aminonaphthalene-2-sulfonic acid is added, and a 15% aqueous sodium carbonate solution is used. The pH was adjusted to 4.0 and stirred for 4 hours. 60 parts of sodium chloride was added to the obtained reaction liquid, and the precipitated solid was separated by filtration and further washed with 100 parts of acetone to obtain 124.0 parts of a wet cake of a compound of the formula (12) as an intermediate. .

83.8 parts of the obtained intermediate of the formula (12) was added to 300 parts of water and the mixture was stirred, and adjusted to pH 10.0 with a 25% aqueous sodium hydroxide solution. Twenty parts of 28% aqueous ammonia and 9.0 parts of copper sulfate pentahydrate were added to the obtained solution, and the mixture was stirred at 90 ° C. for 2 hours. 25 parts of sodium chloride was added to the obtained reaction liquid, and the precipitated solid was separated by filtration and further washed with 100 parts of acetone to obtain 40.0 parts of a wet cake of a compound of the formula (13). The wet cake was dried with a hot air dryer at 80 ° C. to obtain 20.0 parts of a compound represented by the following formula (13).

(Composition example 5)
4.0 parts of commercially available 4-amino-4'-nitrostilbene-2,2'-disulfonic acid and 2.8 parts of sodium carbonate are added to 30 parts of N-methyl-2-pyrrolidone and then 4-methoxybenzoyl chloride After 3.4 parts were dropped for 5 minutes, the mixture was stirred at 110 ° C. for 6 hours. The obtained reaction solution was added to 100 parts of water, and the precipitated solid was separated by filtration and further washed with 100 parts of acetone to obtain 10.0 parts of a wet cake. The wet cake was dried with a hot air dryer at 80 ° C. to obtain 3.0 parts of a compound (λmax: 370 nm) of the following formula (14).

Synthesis Example 6
Surfactant (0.22 parts of "Leocor TD90" manufactured by Lion Corporation) is added to 400 parts of ice water with reference to Japanese Patent Publication No. 50-033814 and Japanese Patent Publication No. 03-294598, and the mixture is vigorously stirred. The reaction mixture was added with 18.4 parts of cyanuric chloride and stirred at 0-5 ° C. for 30 minutes to obtain a suspension, to which 25.3 parts of aniline-2,5-disulfonic acid was added, and the pH was 4-6. The mixture was stirred at 0 to 30 ° C. for 4 hours, subsequently, 18.5 parts of 4,4′-diaminostilbene-2,2′-disulfonic acid was added, and the mixture was stirred at pH 4 to 8 and 20 to 50 ° C. for 6 hours. 11 parts of diethanolamine is added to the reaction solution and stirred at pH 8-10, 40-70 ° C. for 6 hours, 80 parts of sodium chloride is added, and the precipitated solid is separated by filtration and further washed with 100 parts of acetone. , Wet wet To obtain a key 100.0 parts of a stilbene compound of the formula by drying the wet cake at 80 ° C. in a hot air dryer (15). (Λmax: 370nm) to obtain 30.0 parts.
A reaction solution was obtained.

Synthesis Example 7
A compound of the following formula (16) was prepared by the same method as in Synthesis Example 6 except that 25.3 parts of aniline-2,5-disulfonic acid used in Synthesis Example 6 was changed to 17.3 parts of 4-aminobenzenesulfonic acid. (lambda) max: 370 nm) 23.0 parts were obtained.

Synthesis Example 8
By the same method as in Synthesis Example 6 except that 11 parts of diethanolamine used in Synthesis Example 6 was changed to 18.8 parts of phenol, 15.0 parts of a compound (λmax: 370 nm) of the following formula (17) was obtained.

Synthesis Example 9
A compound of the following formula (18) by the same method as in Synthesis Example 6 except that 25.3 parts of aniline-2,5-disulfonic acid used in Synthesis Example 6 is changed to 17.2 parts of 4-aminobenzenesulfonic acid amide 23.0 parts of (λmax: 370 nm) were obtained.

Example 1
(Production of polarized light emitting element)
A 75 μm thick polyvinyl alcohol film (VF-PS # 7500 manufactured by Kuraray Co., Ltd.) was immersed in warm water at 40 ° C. for 3 minutes to swell the film. A film obtained by swelling was prepared by adding 0.05 part of an aqueous solution of 4,4'-bis- (sulfostyryl) biphenyl disodium (TAFOPAL NFW Liquid, manufactured by BASF) described in Compound Example 5-1, and 1.0 part of sodium sulfate. The plate was immersed in an aqueous solution of 45 ° C. containing 1000 parts of water for 10 minutes. The obtained film was immersed in a 3% aqueous boric acid solution for 5 minutes at 50 ° C. and stretched 5.0 times. The film obtained by stretching was washed with water at normal temperature for 20 seconds while maintaining tension, and dried to obtain a polarized light emitting device. The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 92.3%.

(Preparation of polarized light emitting plate)
The both sides of a triacetylcellulose film (ZRD-60 manufactured by Fujifilm Co., Ltd.) containing no ultraviolet light absorber are treated with a 1.5 N aqueous solution of sodium hydroxide at 35 ° C. for 10 minutes, washed with water, and then 70 ° C. Dried for 10 minutes. A triacetyl cellulose film treated with sodium hydroxide is laminated via an aqueous solution containing 4% of polyvinyl alcohol resin (NH-26 manufactured by Nippon Shokuhin Bokubar Co., Ltd.) on both sides of the polarized light emitting element prepared above to obtain polarized light. A light emitting plate was obtained. The obtained polarized light emitting plate exhibited substantially the same optical characteristics as the polarized light emitting element.

[Examples 2 to 7]
In the polarized light-emitting element produced in Example 1, the time (10 minutes) for immersing the swollen film in an aqueous solution at 45 ° C. containing the compound described in Compound Example 5-1 is 9 minutes, 30 seconds, 9 minutes, 8 minutes Polarized light emitting elements having different values of order parameters were produced in the same manner as in Example 1 except that the film was immersed for 30 minutes, 8 minutes, 7 minutes 40 seconds, and 7 minutes 30 seconds.

[Comparative Example 1 and Comparative Example 2]
In the polarized light-emitting element produced in Example 1, the time (10 minutes) for immersing the swollen film in an aqueous solution at 45 ° C. containing the compound described in Compound Example 5-1 was changed to 5 minutes and 2 minutes, respectively. Polarized light-emitting elements different in value of order parameter were produced in the same manner as in Example 1 except for immersion.

In each of the measurement samples obtained in Examples 1 to 7, the ECR exhibited the highest value of the order parameter (OPD) at the wavelength at which the difference between Ky and Kz is the largest and the measured contrast (ECR). The values of are shown in Table 1 and the results obtained in Comparative Examples 1 and 2 in the same manner are shown in Table 2, respectively. Further, FIG. 1 shows the relationship between OPD and ECR in Examples 1 to 7 and Comparative Examples 1 and 2.

From the above Tables 1 and 2 and FIG. 1, it is understood that the light emission contrast is dramatically improved when the value of OPD is 0.81 or more, and the value of ECR greatly exceeds 10 along therewith. From this result, it is understood that when the OPD value of the polarized light emitting element is 0.81 or more, the contrast of polarized light emission is remarkably improved.

[Example 8]
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 1 except that the compound of the above formula (7) produced in Synthesis Example 1 was used instead of Compound Example 5-1 used in Example 1. . The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 91.8%.

[Examples 9 to 13]
In the polarized light emitting device produced in Example 8, after the compound represented by the above formula (7) is contained in a base material, the draw ratio (5.0 times) of the base material is 4.5, 4. Polarized light-emitting elements different in value of the order parameter were produced in the same manner as in Example 8 except that the magnification was changed to 3 times, 4.0 times, 3.5 times, and 3.3 times, respectively.

Example 14
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 1 except that the compound of the above formula (15) produced in Synthesis Example 6 was used instead of the compound example 5-1 used in Example 1. . The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 92.1%.

[Example 15]
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 1 except that the compound of the above formula (16) produced in Synthesis Example 7 was used instead of Compound Example 5-1 used in Example 1. . The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 91.7%.

[Example 16]
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 1 except that the compound of the above formula (17) produced in Synthesis Example 8 was used instead of Compound Example 5-1 used in Example 1. . The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 91.5%.

[Example 17]
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 1 except that the compound of the above formula (18) produced in Synthesis Example 9 was used instead of Compound Example 5-1 used in Example 1. . The visibility-corrected single transmittance (Ys) of the obtained polarized light emitting element showed 91.6%.

[Comparative Examples 3 to 6]
In the polarized light emitting device produced in Example 8, after the compound represented by the formula (7) is contained in the base material, the draw ratio (5.0 times) of the base material is 3.2 times, 3.0 Polarized light-emitting elements different in value of the order parameter were produced in the same manner as in Example 8 except that stretching was carried out by changing them by a factor of 2, 2.8 and 2.6.

In each of the measurement samples obtained in Examples 8 to 13, the value of the order parameter (OPD) at the wavelength at which the difference between Ky and Kz is the largest, and the ECR that showed the highest value in the values of the measured contrast (ECR) The values of are shown in Table 3, and the results obtained in Comparative Examples 3 to 6 in the same manner are shown in Table 4. Further, FIG. 2 shows the relationship between OPD and ECR in Examples 8 to 13 and Comparative Examples 3 to 6. Furthermore, in each of the measurement samples obtained in Examples 1, 8 and 14 to 17 in which polarized light emitting dyes are different, the value of the order parameter (OPD) at the wavelength at which the difference between Ky and Kz is the largest and the measured contrast (ECR) The value of ECR which showed the highest value in the value of) is shown in Table 5.

From the above Tables 3 to 5 and FIG. 2, it is understood that the light emission contrast is dramatically improved when the OPD value is 0.81 or more, and the ECR value greatly exceeds 10 along with this. From this result, it is understood that the contrast of polarized light emission is remarkably improved when the OPD value of the polarized light emitting element is 0.81 or more.

Comparative Example 7
A polarized light emitting device was produced according to the same formulation as the method described in Example 1 of US Pat. No. 3,276,316. Specifically, a 75 μm thick polyvinyl alcohol film (“VF-PS # 7500” manufactured by Kuraray Co., Ltd.) was stretched by 4 times. The obtained film is immersed in a dyeing solution at normal temperature contained in Compound Example 5-1, taken out from the immersed solution, and then stretched so that the length of the substrate is 4.2 times, and polarized light A light emitting element was obtained. A polarized light emitting plate was produced in the same manner as the method for producing a polarized light emitting plate in Example 1 except that this polarized light emitting element was used. The OPD value of the obtained polarized light emitting element was 0.753, and the ECR value of the polarized light emission was 5.0.

Comparative Example 8
A polarized light emitting element was produced according to the same formulation as the method described in Example 1 of JP-A-4-226162. Specifically, 0.43% by weight of a compound represented by Compound Example 5-1 is added to a polyvinyl alcohol resin ("PVA-117" manufactured by Kuraray Co., Ltd.) having a degree of hydrolysis of 99% or more, mixed, and dried. By forming a film so as to have a film thickness of 75 μm later, a polyvinyl alcohol film as a substrate was manufactured. Subsequently, uniaxial light stretching was carried out so that the length of the produced film might be 7.0 times, and a polarization light emitting element was produced. The OPD value of the obtained polarized light emitting element was 0.679, and the ECR value of the polarized light emission was 3.4.

[Example 18]
(Production of polarized light emitting element)
A polyvinyl alcohol film ("VF-PS # 7500" manufactured by Kuraray Co., Ltd.) having a thickness of 75 μm was immersed in water at 40 ° C. for 3 minutes to swell the film. A film obtained by swelling was obtained by adding 0.3 parts of the compound of the formula (7) obtained in Synthesis Example 1, 0.15 parts of the compound of the formula (9) obtained in Synthesis Example 2, and 1 The film was immersed in an aqueous solution at 45 ° C. containing 0.05 parts of water and 1000 parts of water for 4 minutes to contain the compound of formula (7) and the compound of formula (9) in a film. The obtained film was immersed in a 3% aqueous boric acid solution for 5 minutes at 50 ° C. and stretched 5.0 times. The film obtained by stretching was washed with water at normal temperature for 20 seconds while maintaining tension, and dried to obtain a polarized light emitting device.

[Example 19]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
In place of 0.3 part of the compound of Formula (7) and 0.15 part of the compound of Formula (9), 0.3 part of the compound of Formula (11) obtained in Synthesis Example 3 and A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 18 except that 0.15 part of the compound of the formula (13) was used.

[Example 20]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
In place of 0.3 part of the compound of Formula (7) and 0.15 part of the compound of Formula (9), 0.3 part of the compound of Formula (14) obtained in Synthesis Example 5 and A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 18 except that 0.15 part of the compound of the formula (13) was used.

[Example 21]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
In place of 0.3 part of the compound of formula (7) and 0.15 part of the compound of formula (9), 0.3 part of the compound of formula (14) obtained in Synthesis Example 5 and Compound Example 5-1 A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 18 except that 1.0 part of the aqueous solution of 4,4'-bis- (sulfostyryl) biphenyl dibasic (Tinopal NFW Liquid, manufactured by BASF) was used. did.

Comparative Example 9
In place of the compound of the formula (7) and the compound of the formula (9), C.I. that is a general dichroic dye that does not show fluorescence emission represented by the formula (19) I. A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 18 except that Direct Yellow 4 was used.

Comparative Example 10
Example except using the compound which is a general dichroic dye which does not show fluorescence emission shown by Formula (20) instead of the compound of Formula (7) and the compound of Formula (9) In the same manner as in No. 18, a polarized light emitting element and a polarized light emitting plate were produced.

Comparative Example 11
Example except using the compound which is a general dichroic dye which does not show fluorescence emission shown by Formula (21) instead of the compound of Formula (7) and the compound of Formula (9) In the same manner as in No. 18, a polarized light emitting element and a polarized light emitting plate were produced.

Table 6 shows the single light transmittance (Ts) at the wavelength showing the maximum degree of polarization of the polarized light emitting devices manufactured in Examples 18 to 21 and Comparative Examples 9 to 11, and the parallel transmittance (Tp) at the wavelength showing the maximum degree of polarization. The orthogonal position transmittance (Tc), the degree of polarization (、), and the visibility corrected single transmittance (Ys) are shown.

Further, in Table 7, the values of Ls and Lw measured at each wavelength of 460 nm, 550 nm, 610 nm and 670 nm and the polarization at Ls in the polarized light emitting elements manufactured in Examples 18 to 21 and Comparative Examples 9 to 11 are shown. The value of chromaticity a ^{* and} the value of hue b ^* measured according to JIS Z 8781-4: 2013 are shown as light emission colors in light emission.

As shown in Table 6, the polarized light emitting elements produced in Examples 18 to 21 function as polarized light emitting elements having an absorption characteristic of light in the ultraviolet light region because the wavelength showing the maximum degree of polarization is 380 nm or less. It turned out that it was doing. In addition, the transmittance in the visible light region (visual sensitivity correction transmittance Ys) is about 90%, and it was found that the ultraviolet light region exhibits a high transparency in the visible light region while having a polarization function. Furthermore, the polarization degree ρ also showed a high value of 95% or more. On the other hand, in the polarized light emitting elements produced in Comparative Examples 9 to 11, the wavelength showing the maximum degree of polarization is 400 nm or more, and the visible light correction single transmittance (Ys) is also lowered. A decrease in the rate was observed.

Furthermore, as shown in Table 7, in the polarized light emitting elements manufactured in Examples 18 to 21, since Lw and Ls were detected, it was found that these polarized light emitting elements emit light when irradiated with ultraviolet light. In addition, since the polarized light emitting elements manufactured in Examples 18 to 21 had a difference between the value of Lw and the value of Ls, it was found that the light emission was polarized. Furthermore, the polarized light emitting elements produced in Examples 18 to 21 exhibit polarized light emission over a broad band of 400 to 700 nm by irradiation with ultraviolet light, and the absolute values of the chromaticity a ^* and the hue b ^* are both It was 5 or less. From this, it is shown that the polarized light emitting elements produced in Examples 18 to 21 function as white light emitting type polarized light emitting elements that emit white polarized light by irradiation of ultraviolet light. On the other hand, it was confirmed that the polarized light emitting elements produced in Comparative Examples 9 to 11 had low values of Ls and did not detect Lw, and therefore showed no polarized light emission or only weak polarized light emission. Therefore, the polarized light emitting elements produced in Comparative Examples 9 to 11 were out of the measurement range for the chromaticity a ^* .

Example 22
(Production of polarized light emitting element)
A 75 μm thick polyvinyl alcohol film (“VF-PS # 7500” manufactured by Kuraray Co., Ltd.) was immersed in warm water at 40 ° C. for 3 minutes to swell the film. A film obtained by swelling was a 0.54 part aqueous solution of 4,4'-bis- (sulfostyryl) biphenyl disodium (Tinopal NFW Liquid manufactured by BASF) described in Compound Example 5-1, and 1.0 part of mirabilite. The substrate was immersed in an aqueous solution at 45 ° C. containing 1000 parts of water for 8 minutes. The obtained film was immersed in a 3% aqueous boric acid solution at 50 ° C. for 5 minutes and stretched 5.0 times. The film obtained by stretching was washed with water at normal temperature for 20 seconds while maintaining tension, and dried to obtain a polarized light emitting device.

(Measurement of secondary ion intensity derived from boron compound)
In the obtained polarized light emitting device, the thickness of the substrate (film thickness of the polarized light emitting device) was 32 μm. When the content of boric acid (boric acid content in the cross section of the substrate) was measured from the surface of the substrate to the thickness direction of the substrate using “ToF-SIMS 300” (manufactured by ION-TOF) Information on the ratio of secondary ion intensity derived from boric acid as shown in Table 8 was obtained. The concentration distribution of boric acid derived from this result was obtained as shown in Table 9.

(Measurement of polarized light emitting dye by Raman spectroscopy)
Using a Raman spectrophotometer ("DXR Raman Microscope" manufactured by Thermo Fisher), Raman spectroscopy was applied while scanning in the thickness direction with respect to the film thickness section of the obtained polarized light emitting device. As a result, the energy of the compound described in Example Compound 5-1 based on 1173 cm ^-1 and 1600 cm ^-1 was detected from the surface layer to 10 μm in a 31 μm-thick film thickness section. From this, it was confirmed that the compound described in Compound Example 5-1 was contained at least from the surface layer of the substrate to a depth of 10 μm.

(Preparation of polarized light emitting plate)
Both sides of the obtained polarized light emitting device were treated with a 1.5 N aqueous solution of sodium hydroxide at 35 ° C. for 10 minutes, washed with water, and then dried at 70 ° C. for 10 minutes. Furthermore, a 4% polyvinyl alcohol resin (Nippon A & V: Poval Co., Ltd. NH on both sides of a polarized light emitting element treated with sodium hydroxide with a triacetyl cellulose film (ZRD-60 made by Fuji Film Co., Ltd.) containing no ultraviolet light absorber It laminated | stacked via the aqueous solution containing -26), and obtained the polarized light-emission board.

[Example 23]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 22 except that the compound of the above formula (7) produced in Synthesis Example 1 was used instead of the compound example 5-1 used in Example 22. . Tables 8 and 9 show information on the concentration distribution of boron. The content of the polarized light emitting dye (the compound of the above formula (7)) in the film thickness section was equivalent to that of Example 22.

Comparative Example 12
In place of compound 5-1 described in Example 22, C.I. I. A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 22 except that Direct Yellow 4 was used.

Comparative Example 13
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 22 except that boron was not used.

(Measurement of secondary ion intensity derived from boron compound)
In the obtained polarized light emitting device, the thickness of the substrate (film thickness of the polarized light emitting device) was 31 μm. When the content of boric acid (boric acid content in the cross section of the substrate) was measured from the surface of the substrate to the thickness direction of the substrate using “ToF-SIMS 300” (manufactured by ION-TOF) It confirmed that it did not contain boron.

(Measurement of polarized light emitting dye by Raman spectroscopy)
Using a Raman spectrophotometer ("DXR Raman Microscope" manufactured by Thermo Fisher), Raman spectroscopy was applied while scanning in the thickness direction with respect to the film thickness section of the obtained polarized light emitting device. As a result, the energy of a compound according to compound example 5-1 based on 1173Cm ^-1 or 1600 cm ^-1, is, in the film thickness cross section of 31 .mu.m, was detected from the surface to 10 [mu] m. From this, it was confirmed that the compound described in Compound Example 5-1 was contained at least from the surface layer of the substrate to a depth of 10 μm.

Comparative Example 14
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
The polarized light-emitting element described in Comparative Example 7 was produced by the same formulation as the method described in Example 1 of US Pat. No. 3,276,316. A polarized light emitting plate was produced in the same manner as in Example 22 except that this polarized light emitting element was used.

(Measurement of secondary ion intensity derived from boron compound)
In the obtained polarized light emitting device, the thickness of the substrate (film thickness of the polarized light emitting device) was 35 μm. When the content of boric acid (boric acid content in the cross section of the substrate) was measured from the surface of the substrate to the thickness direction of the substrate using “ToF-SIMS 300” (manufactured by ION-TOF) It confirmed that it did not contain boron.

(Measurement of polarized light emitting dye by Raman spectroscopy)
Using a Raman spectrophotometer ("DXR Raman Microscope" manufactured by Thermo Fisher), Raman spectroscopy was applied while scanning in the thickness direction with respect to the film thickness section of the obtained polarized light emitting device. As a result, 1173Cm ^-1, as well as the energy of the polarized luminescence dyes based on 1600 cm ^-1 is at 35μm thickness cross section of was detected from the surface to 2 [mu] m. From this, it was confirmed that the polarized light emitting dye was contained only from the surface layer of the substrate to a depth of 2 μm.

Comparative Example 15
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
A polarized light emitting device was produced by impregnating the polarized light emitting device manufactured in Comparative Example 14 with an aqueous solution at 40 ° C. containing 5% by weight of boron for 5 seconds. A polarized light emitting plate was produced in the same manner as in Example 22 except that this polarized light emitting element was used.

(Measurement of polarized light emitting dye by Raman spectroscopy)
Using a Raman spectrophotometer ("DXR Raman Microscope" manufactured by Thermo Fisher), Raman spectroscopy was applied while scanning in the thickness direction with respect to the film thickness section of the obtained polarized light emitting device. As a result, 1173cm ^-1, as well as the energy of the polarized luminescence dye-based 1600 cm ^-1, in the film thickness cross section of 32 [mu] m, was detected from the surface to 2 [mu] m. From this, it was confirmed that the polarized light emitting dye was contained only from the surface layer of the substrate to a depth of 2 μm.

Comparative Example 16
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
A polarized light emitting element was produced according to the same formulation as the method described in Example 1 of JP-A-4-226162. Specifically, 0.43% by weight of a compound represented by Compound Example 5-1 is added to a polyvinyl alcohol resin ("PVA-117" manufactured by Kuraray Co., Ltd.) having a degree of hydrolysis of 99% or more, mixed, and dried. By forming a film so as to have a film thickness of 75 μm later, a polyvinyl alcohol film as a substrate was manufactured. Next, uniaxial light stretching was performed at 130 ° C. for 14 minutes so that the length of the produced film was 7.0 times, to prepare a polarized light emitting element.

(Measurement of secondary ion intensity derived from boron compound)
In the obtained polarized light emitting device, the thickness of the substrate (film thickness of the polarized light emitting device) was 28 μm. When the content of boric acid (boric acid content in the cross section of the substrate) was measured from the surface of the substrate to the thickness direction of the substrate using “ToF-SIMS 300” (manufactured by ION-TOF) It confirmed that it did not contain boron.

(Measurement of polarized light emitting dye by Raman spectroscopy)
Using a Raman spectrophotometer ("DXR Raman Microscope" manufactured by Thermo Fisher), Raman spectroscopy was applied while scanning in the thickness direction with respect to the film thickness section of the obtained polarized light emitting device. As a result, the energy of the polarized light emitting dye based on 1150 cm ^-1 and 1600 cm ^-1 was uniformly detected in the film thickness direction from the surface layer in a film thickness section of 28 μm. From this, it was confirmed that the polarized light emitting dye is uniformly contained in the surface layer of the substrate.

Tables 8 and 9 below show data on the ratio (intensity ratio) of secondary ion intensity obtained by the ToF-SIMS measurement in the polarized light emitting elements manufactured in Examples 22 and 23 and Comparative Example 15, respectively. The ratio of the secondary ion intensity is measured at each distance with respect to the secondary ion intensity value, where the value of the highest secondary ion intensity (maximum secondary ion intensity) in each measurement is 1 in each polarization light emitting element. Is the ratio of the secondary ion intensity values. In addition, the thickness of the substrate (film thickness of the polarized light emitting element) is represented by L. For example, in Table 8, the ratio of the secondary ion intensity at a distance of 1 / 2L toward the thickness direction from the substrate front surface represents I _1, toward the thickness direction from the substrate front surface (0 .mu.m) The ratio of the secondary ion intensity detected up to a distance of 1⁄4 L and the secondary ion intensity detected up to a distance of 1⁄4 L in the thickness direction from the substrate backside surface (32 μm) The intensity ratio showing the maximum value represents I ₂ among the ratios of

Further, in Table 9 below, the ratio of the secondary ion intensity (0 to 1/4 L average 1) is the ratio of the secondary ion intensity detected from the front surface of the base to the distance of 1⁄4 L. Represents the average value (I ₃ ). The ratio of the secondary ion strength (average between 1/2 and 1/4 L) is 1 in the thickness direction from the half (center) of the thickness L of the substrate toward the front and back surfaces of the substrate. It represents the average value (I ₄ ) of the ratio of secondary ion intensities detected up to a distance of 4 L. The ratio of secondary ion intensities (0 to 1/4 L average 2) means the average value (I ₃ ) of the ratio of secondary ion intensities detected from the back surface of the substrate to a distance of 1⁄4 L Represent. Ratio of secondary ion intensity (0 to 1/4 L integral 1), ratio of secondary ion intensity (1/2 to 1/4 L integral), ratio of secondary ion intensity (0 to 1/4 L integral 2) and Represents the integral value of the secondary ion intensity ratio, and the secondary ion intensity ratio (0 to 1/4 L integral 1) and the secondary ion intensity ratio (0 to 1/4 L integral 2) are I ₅ , the ratio of the secondary ion intensity (1/2 ~ 1 / 4L between integration) corresponds respectively to _{I 6.} The integral value is the integral of the value obtained every 2 μm in the thickness direction of the substrate.

From the results of Tables 8 and 9 above, the polarized light emitting elements produced in Examples 22 and 23 have relatively high values also in the vicinity of the center (between 1/2 L and 1/4 L) in the thickness direction of the substrate. Shows the ratio of secondary ion intensity. From this, it can be seen that in the polarized light emitting elements produced in Examples 22 and 23, a large amount of boron is present not only near the surface of the substrate but also near the center. On the other hand, in the polarized light emitting element produced in Comparative Example 15, the value of the ratio of the secondary ion intensity near the center was low, and the amount of boron near the center was significantly less than that near the surface of the substrate.

Table 10 below shows the wavelengths indicating the maximum degree of polarization of the polarized light emitting elements produced in Examples 22 and 23 and Comparative Examples 12 to 16, the single transmittance (Ts) at the wavelength indicating the maximum degree of polarization, and the parallel transmittance ( Tp), orthogonal position transmittance (Tc), polarization degree ((), and visibility corrected single transmittance (Ys) are shown.

Table 11 below shows the wavelengths showing the maximum polarized light emission in the polarized light emitting elements manufactured in Examples 22 and 23 and Comparative Examples 13 to 16, Ls and Lw at that wavelength, and the ratio of Ls to Lw. In addition, since the polarized light emitting element produced in Comparative Example 12 did not exhibit polarized light emission, Ls and Lw were not measured.

As shown in Table 10 above, it can be seen that the polarized light emitting elements produced in Examples 22 and 23 absorb light of the following wavelength band at 400 nm, and have a polarization function in that band. In addition, since the polarization light emitting devices produced in Examples 22 and 23 have a higher degree of polarization than the polarization light emitting devices produced in Comparative Examples 13 to 16, their polarization function is superior to that of Comparative Examples 12 to 16. Furthermore, it was found that the polarized light emitting elements produced in Examples 22 and 23 had a transmittance in the visible range (visual sensitivity corrected transmittance Ys) of about 90%, and also had high transparency in the visible light range.

In addition, as shown in Table 11, since Lw and Ls were detected, the polarized light emitting elements produced in Examples 22 and 23 exhibited polarized light emission by irradiation with ultraviolet light, and the polarization degree of the polarized light ( Ls / Lw) was also higher than that of the polarized light-emitting element produced in Comparative Examples 13-16. Furthermore, Comparative Example 12 using a dichroic dye used in a general polarizing plate did not exhibit polarized light. From the above evaluation results, it can be seen that the polarized light emitting elements produced in Examples 22 and 23 can emit polarized light and have a high degree of polarization in polarized light emission.

[Example 24]
(Production of polarized light emitting element)
A 75 μm thick polyvinyl alcohol film (VF-PS # 7500 manufactured by Kuraray Co., Ltd.) was immersed in warm water at 40 ° C. for 3 minutes to swell the film. A film obtained by swelling is a 0.34 part aqueous solution of 4,4'-bis- (sulfostyryl) biphenyl disodium (Tinopal NFW Liquid, manufactured by BASF) described as the compound example 5-1, and 1.0 part of mirabilite. The plate was immersed in an aqueous solution at 45 ° C. containing 1000 parts of water for 8 minutes. The obtained film was immersed in a 3% aqueous boric acid solution at 50 ° C. for 5 minutes and stretched 5.0 times. The film obtained by stretching was washed with water at normal temperature for 20 seconds while maintaining tension, and dried to obtain a polarized light emitting device.

(Preparation of polarized light emitting plate)
The both sides of a triacetylcellulose film (ZRD-60 manufactured by Fujifilm Co., Ltd.) containing no ultraviolet light absorber are treated with a 1.5 N aqueous solution of sodium hydroxide at 35 ° C. for 10 minutes, washed with water, and then 70 ° C. Dried for 10 minutes. A triacetyl cellulose film treated with sodium hydroxide on both sides of a polarized light emitting element is 4% by weight of a polyvinyl alcohol resin (NH-26 manufactured by Nippon Shokubai Bi-Poval), generally black as a visible light absorbing type dye Polarized luminescence in which a visible light absorbing dye-containing layer is further provided as an adhesive layer by laminating with an aqueous solution containing 0.2% by weight of the compound described in Example 1 of Patent No. 4764829 used as a dye A polarized light emitting plate provided with an element was produced.

[Example 25]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
Polarized light-emitting device and polarized light in the same manner as in Example 24 except that in addition to Compound Example 5-1 used in Example 24, the compound of the above formula (7) prepared in Synthesis Example 1 was used in 0.08 part A board was made.

[Example 26]
(Preparation of Polarized Light-emitting Element and Polarized Light-emitting Plate)
Generally used as an orange dye instead of an aqueous solution containing 0.2% by weight of the compound (visible light absorbing dye) described in Example 1 of the real patent No. 4764 829 used in Example 24 C. which has the highest light absorption action at 445 nm. I. A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 24 except that an aqueous solution containing 0.1% by weight of Direct Orange 39 was used.

[Example 27]
(Production of polarized light emitting element)
A 75 μm thick polyvinyl alcohol film (VF-PS # 7500 manufactured by Kuraray Co., Ltd.) was immersed in warm water at 40 ° C. for 3 minutes to swell the film. A film obtained by swelling is a 0.34 part aqueous solution of 4,4'-bis- (sulfostyryl) biphenyl disodium (Tinopal NFW Liquid manufactured by BASF) described in Compound Example 5-1, 1.0 part of mirabilite The substrate was immersed in an aqueous solution at 45 ° C. containing 1000 parts of water for 8 minutes. The obtained film was immersed in a 3% aqueous boric acid solution at 50 ° C. for 5 minutes and stretched 5.0 times. A film obtained by stretching is kept at a tension, and 0.1 part of the compound described in Example 1 of Japanese Patent No. 4764 829 and 1000 parts of 40 ° C. containing 1.0 part of sodium tripolyphosphate. It was immersed in warm water for 20 seconds and dried to prepare a polarized light emitting element.

The both sides of a triacetylcellulose film (ZRD-60 manufactured by Fujifilm Co., Ltd.) containing no ultraviolet light absorber are treated with a 1.5 N aqueous solution of sodium hydroxide at 35 ° C. for 10 minutes, washed with water, and then 70 ° C. Dried for 10 minutes. A polarized light emitting plate was obtained by laminating a triacetyl cellulose film treated with sodium hydroxide on both sides of a polarized light emitting element via an aqueous solution containing 4% of polyvinyl alcohol resin (NH-26 manufactured by Nippon Shokuhin Bobival Co., Ltd.) Made. The produced polarized light emitting plate exhibited the same optical characteristics as the polarized light emitting element.

[Example 28]
(Production of polarized light emitting element)
In Example 27, the film obtained by stretching was maintained in tension, and 0.1 part of the compound described in Example 1 of Patent No. 4764429 and 1.0 part of sodium tripolyphosphate 40 It was immersed in 1000 parts of hot water of 20 ° C. for 20 seconds and stretched 5.0 times. Thereafter, a polarized light emitting element having absorption oriented also in the orthogonal direction in the same manner as in Example 27 except that the polarized light emitting element was produced while drying it while drawing it further 1.3 times in the orthogonal direction to the drawing direction. And the polarization light-emitting plate was produced and used as a measurement sample.

Comparative Example 17
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 24 except that the compound described in Example 1 of Japanese Patent No. 4764 829 as a visible light absorbing dye was not used.

Comparative Example 18
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 25 except that the compound described in Example 1 of Japanese Patent No. 4764 829 as a visible light absorbing dye was not used.

Comparative Example 19
A polarized light emitting element and a polarized light emitting plate were produced in the same manner as in Example 27 except that the compound described in Example 1 of Japanese Patent No. 4764 829 as a visible light absorbing dye was not used.

(Measurement of polarization degree of polarized light emission)
The ultraviolet rays of 365 nm were irradiated from a light source ("LED M365L2", Thorlabs), and they were prepared in Examples 24 to 28 and Comparative Examples 17 to 19 using a spectroscope ("Spectropolarimeter Poxi-Spectora", Tokyo Instruments) The Stokes spectrum of the polarized light emission from the polarized light emitting plate was measured, and the degree of polarization of the polarized light was measured.

Table 12 shows the wavelength (λ abs max) showing the maximum degree of polarization in the polarized light emitting plates manufactured in Examples 24 to 28 and Comparative Examples 17 to 19, the maximum transmittance wavelength of visible light correction single transmittance (Ys) and polarized light emission The result of the degree of polarization (DOP) in the range of (460 nm) to ± 30 nm is shown.

As shown in Table 12 above, the polarized light emitting plates manufactured in Examples 24 to 28 have high transmittance in the visible light region while having the function of absorbing light in the ultraviolet light to near-ultraviolet visible light region. It can be seen that it has polarized light emission. Moreover, compared with the polarized light emitting plates manufactured in Comparative Examples 17 to 19, the polarized light emitting boards manufactured in Examples 24 to 28 actually showed a degree of emission polarization, although the decrease in transmittance was less than 2%. It can be seen that (DOP) is higher. In particular, when Example 25 is compared with Comparative Example 18, the DOP of the polarized light emitting plate manufactured in Example 25 is improved by 3.48%.

(Durability test)
Each of the measurement samples prepared in Examples 1 to 28 was placed for 1000 hours in an environment of 105 ° C., 1000 hours in an environment of 60 ° C. and 90% relative humidity, and comparison of polarized luminescence before and after 1000 hours. Conducted a durability test. As a result, no reduction in the degree of polarization and no significant change in the polarization emission characteristics were observed. From this, it is shown that all of the measurement samples produced in Examples 1 to 28 have high durability even in a severe environment.

Thus, the polarized light emitting element and the polarized light emitting plate according to the present invention can be applied as a self-luminous polarizing film, that is, a polarized light emitting film. In addition, such a polarized light emitting element and a polarized light emitting plate have high transmittance in the visible light range while having excellent durability. In general, when the contrast value exceeds 10, the visibility by human eyes is dramatically improved. For example, the contrast value of characters in newspaper paper and the contrast value of general book characters are in the range of 5 to 10. The polarized light emitting element and the polarized light emitting plate according to the present invention enable polarized light emission having a contrast value which greatly exceeds this range. Therefore, the polarized light emitting element and the display device using the polarized light emitting plate according to the present invention have high transparency in the visible light region and can display an image by polarized light emission over a long period of time. Furthermore, it is applicable to a wide range of applications, such as a transparent display (see-through display). Furthermore, a polarized light emitting element produced using a stilbene compound as the present polarized light emitting dye can emit light by ultraviolet light. Therefore, in the polarized light emitting element and the polarized light emitting plate according to the invention, a functional medium such as a display, a sensor or the like which requires high security such that the functional expression is required by irradiation of non-visible light such as ultraviolet light It is also possible to apply to

Claims

A polarized light emitting element in which at least one polarized light emitting dye capable of polarized light emission is oriented on a substrate by using absorption of light,
The polarized light emitting dye exhibits a polarization action in the wavelength region of the absorbed light, and at the wavelength at which the polarization action is the highest, the value of the order parameter (OPD) calculated by the following formula (I) is 0. A polarized light emitting device characterized in that it is 81 to 0.95.

(In the above formula (I), Ky represents the light transmittance when light polarized orthogonal to the axis showing absorption of the highest light in the polarized light emitting element is incident, and Kz represents the polarized light emission Indicates the light transmittance when light polarized parallel to the axis showing the highest light absorption in the device is incident.)
The polarized light emitting device according to claim 1, wherein the at least one polarized light emitting pigment has fluorescence emission characteristics.
The at least one type of polarized light emitting dye has a fluorescence emission characteristic capable of polarized light emission of light in the visible light region by absorbing light in the ultraviolet light region to the near ultraviolet visible light region. Polarized light emitting element.
The polarized light emitting device according to any one of claims 1 to 3, wherein the at least one polarized light emitting dye has a biphenyl skeleton or a stilbene skeleton.
The polarized light emitting element exhibits an emission color having an absolute value of chromaticity a * measured according to JIS Z 8781-4: 2013 of 5 or less and an absolute value of hue b * of 5 or less. The polarized light emitting element as described in.
The polarized light emitting element according to claim 4 or 5, wherein the at least one polarized light emitting dye is a compound represented by the following formula (1) or a salt thereof.

(Wherein, L and M each independently represent a nitro group, an amino group which may have a substituent, a carbonylamide group which may have a substituent, a naphthotriazole group which may have a substituent) A C 1 -C 20 alkyl group which may have a substituent, a vinyl group which may have a substituent, an amido group which may have a substituent, a ureide group which may have a substituent, It is selected from the group consisting of an aryl group which may have a substituent and a carbonyl group which may have a substituent.)
The polarized light-emitting device according to claim 6, wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or formula (3).

(In formula (2), X represents a nitro group or an amino group which may have a substituent, and R has a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a nitro group or a substituent Represents an alkyl group which may be substituted, an alkoxy group which may have a substituent, or an amino group which may have a substituent, and n represents an integer of 0 to 3.)

(In the formula (3), Y is a C 1 -C 20 alkyl group which may have a substituent, a vinyl group which may have a substituent, or an aryl group which may have a substituent And Z represents a nitro group or an amino group which may have a substituent.)
In the above formula (2), X is a nitro group, a C 1 -C 20 alkylcarbonylamino group which may have a substituent, an arylcarbonylamino group which may have a substituent, C 1 -C 20 alkylsulfonyl The polarized light-emitting device according to claim 7, which is an amino group or an arylsulfonylamino group which may have a substituent.
The polarized light-emitting device according to claim 7 or 8, wherein in the formula (2), R is a hydrogen atom and n is 1 or 2.
The polarized light emitting element according to claim 7 or 8, wherein in the formula (2), R is a methyl group.
The polarized light-emitting device according to any one of claims 7 to 10, wherein Y is an aryl group which may have a substituent in the formula (3).
The polarized light emitting device according to any one of claims 1 to 11, wherein the substrate contains a hydrophilic polymer.
The polarized light-emitting device according to claim 12, wherein the hydrophilic polymer comprises polyvinyl alcohol.
The polarized light emitting device according to any one of claims 1 to 13, wherein the substrate is an oriented hydrophilic polymer film.
The polarized light emitting device according to any one of claims 1 to 14, wherein the substrate further comprises a boron compound.
The secondary ion intensity derived from the boron compound measured by time-of-flight secondary ion mass spectrometry in the thickness direction of the substrate satisfies the relationship of I 2 ≦ 30 × I 1 ,
I 1 is secondary ion intensity detected in the thickness detected maximum secondary least distance 1 / 2L toward the one side surface in the thickness direction of the relative ionic strength substrate at L of the base material Represents the ratio of
I 2 is detected between a distance of 1/4 L from the both surfaces of the substrate to the maximum secondary ion intensity detected at the thickness L of the substrate respectively in the thickness direction of the substrate The polarized light emitting device according to claim 15, which represents the maximum value of the ratio of the secondary ion intensities.
The secondary ion intensity derived from the boron compound further satisfies the relationship of I 3 ≦ 5 × I 4 ,
I 3 is the ratio of the secondary ion intensity detected between the distance of 1 / 4L from at least one side surface of said substrate with respect to the maximum secondary ion intensity detected by the thickness L of the base material Represents the average value,
I 4 is a distance of 1⁄4 L in the thickness direction from the center of the thickness L to the maximum secondary ion intensity detected at the thickness L of the substrate toward both surfaces of the substrate The polarized light emitting device according to claim 16, which represents an average value of the ratio of secondary ion intensities detected between them.
The secondary ion intensity derived from the boron compound further satisfies the relationship of I 5 ≦ 2 × I 6 ,
I 5 is the ratio of the secondary ion intensity detected between the distance of 1 / 4L from at least one side surface of said substrate with respect to the maximum secondary ion intensity detected by the thickness L of the base material Represents an integral value,
I 6 up to a distance of 1⁄4 L each in the thickness direction from the center of the thickness L to the maximum secondary ion intensity detected at the thickness L of the substrate from the center to both surfaces of the substrate The polarized light emitting element according to claim 16 or 17, which represents an integral value of a ratio of secondary ion intensities detected between the two.
The polarized light emitting device according to any one of claims 16 to 18, wherein the concentration distribution of the secondary ion intensity derived from the boron compound is present at least between 3 μm and 20 μm from the surface of the substrate.
The polarized light emitting device according to any one of claims 1 to 19, wherein the polarized light emitting device further comprises at least one fluorescent dye and / or an organic dye different from the polarized light emitting dye.
The polarized light emitting device according to any one of claims 1 to 20, further comprising a visible light absorbing dye-containing layer on at least one surface of the polarized light emitting device.
22. The polarized light emitting device according to claim 21, wherein a reduction rate of visible light transmittance by the visible light absorbing dye containing layer is 50% or less.
22. The visible light absorbing dye-containing layer has light absorption anisotropy, and the absorption direction of light based on the light absorption anisotropy is orthogonal to polarized light emission by the polarized light emitting element. Or 22. The polarized light-emitting element as described in 22.
A polarized light emitting plate comprising the polarized light emitting device according to any one of claims 1 to 23 and a transparent protective layer provided on one side or both sides of the polarized light emitting device.
The polarized light-emitting plate according to claim 24, wherein the transparent protective layer is a plastic film having no ultraviolet light absorption function.
26. The polarized light emitting plate according to claim 24, further comprising a support layer.
A display device comprising the polarized light emitting element according to any one of claims 1 to 23, or the polarized light emitting plate according to any one of claims 24 to 26.
A visible light absorbing dye-containing layer is further provided on at least one surface of the polarized light emitting element, and
The display device according to claim 27, wherein the visible light absorbing dye-containing layer is provided at least on the viewer side.
20. The polarized light according to any one of claims 15 to 19, which is stretched while containing the boron compound in the substrate containing the polarized light-emitting dye, or stretched after containing the boron compound in the substrate. Method of manufacturing a light emitting device