TW202128887A - Polarizing luminescent element, polarizing luminescent plate, and display - Google Patents

Abstract

The polarized light emitting element is a polarized light emitting device provided with a base material, wherein

the base material contains at least one kind of polarized luminescent dye,

the polarized luminescent dye is oriented toward the base material,

the polarized light emitting element exhibits a polarizing action in the wavelength region of the light to be absorbed,

moreover, when polarized light having a wavelength having the highest polarization action is incident, the absorbance (Abs-Ky) on the axis with the least absorption is 0.0001 to 0.12.

Description

Polarized light emitting element, polarized light emitting plate and display device

The present invention relates to a polarized light emitting element capable of realizing high-contrast polarized light emission, a polarized light emitting panel provided with the polarized light emitting element, a display device (display), and a manufacturing method of the polarized light emitting element.

The polarizing plate with the function of light penetration and shielding is the basic component of display devices such as liquid crystals with light switching functions and liquid crystal displays (LCD). The application areas of the LCD can also include: early electronic computers and clocks and other small machines, as well as notebook computers, word processors, liquid crystal projectors, liquid crystal TVs, car navigation, indoor/outdoor information display devices, and measurement equipment. In addition, such a polarizing plate system can also be applied to lenses with polarizing function, and also used in sunglasses to improve visibility, polarized glasses corresponding to 3D TVs in recent years, etc., and also used and/or practical. In portable information terminals led by wearable terminals. In this way, the use of the polarizing plate covers a wide range, so the polarizing plate is used in a wide range of use environments such as low temperature to high temperature, low humidity to high humidity, and low light intensity to high light intensity. Therefore, in order to correspond to various applications, a polarizing plate with high polarization performance and excellent durability is required.

Generally speaking, polyvinyl alcohol is produced by a film of stretched orientated polyvinyl alcohol or its derivatives, or by dehydrogenation of a polyvinyl chloride film or a polyvinyl alcohol-based film. A substrate such as a polyolefin-based film after orientation is dyed with a dichroic dye (iodine or a dichroic dye) (the substrate is made to contain the dichroic dye) to produce a polarizing element. Since the polarizing plate composed of such a conventional polarizing element contains a dichroic pigment having a function of absorbing light in the visible light region, the transmittance in the visible light region is reduced. For example, the transmittance of a general polarizer on the market is 35 to 45%.

The reason why the transmittance in the visible light region is as low as 35 to 45% is that the polarizing plate contains dichroic pigments. In order for the polarizer to display 100% polarization, when there are x-axis light and y-axis light in the two-dimensional plane, it must absorb the light of one axis. In order to absorb the light of one of the axes, the polarizing plate contains dichroic pigments. Therefore, the transmittance in the visible light region is theoretically less than 50% with respect to 100% of the amount of light. Furthermore, due to the orientation of the dichroic pigment, the light loss caused by the film medium, and the interface reflection on the film surface, the transmittance will be lower than the theoretical value of 50%. In view of such a problem that the transmittance of the conventional polarizing plate becomes low, in terms of the technique of maintaining a certain transmittance in the visible light region and imparting a polarization function, Patent Document 1 describes a polarizing plate for ultraviolet rays. However, when using this polarizing plate for ultraviolet rays, the polarizing plate will have a yellow tint, and it is only possible to provide a polarizing plate that exhibits the polarization function by light around 410nm. In other words, such a polarizing plate for ultraviolet rays is not a polarizing plate that exhibits a broad polarization function in the visible light region, but a polarizing plate that only functions in a specific ultraviolet or visible light region.

Generally speaking, if a polarizer with a low transmittance in the visible light region or a polarizer with a low degree of polarization is used in the manufacture of displays, the brightness or contrast of the entire display will be reduced. In order to solve this problem, a method of obtaining polarized light without using the conventional polarizer is studied. do As one of the methods, Patent Documents 2 to 6 disclose a device that exhibits polarized light emission (polarized light emitting device).

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] International Publication No. 2005/001527

[Patent Document 2] JP 2008-224854 A

[Patent Document 3] JP 2013-121921 A

[Patent Document 4] International Publication No. 2011/111607

[Patent Document 5] Specification of US Patent No. 3,276,316

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

[Patent Document 7] International Publication No. 2019/022212

However, the polarized light emitting element series described in Patent Documents 2 to 4 contain special metals, such as rare and expensive metals such as lanthanides and europium. Therefore, the cost is high and it is very difficult to manufacture, so it is not suitable for mass production. Furthermore, these polarized light-emitting elements are difficult to use in displays due to their very low degree of polarization, and it is very difficult to obtain linearly polarized light emission. Furthermore, there is a problem that only circularly polarized light or elliptical polarized light of a specific wavelength can be obtained. Therefore, even if the polarized light-emitting elements described in Patent Documents 2 to 4 are used in displays, there are disadvantages such as dark light-emitting brightness, low contrast, and difficulty in designing liquid crystal cells.

On the other hand, Patent Documents 5 and 6 disclose an element that irradiates ultraviolet light to exhibit polarized light emission. However, there is a problem that the polarization of the light emitted by the device is low, and the durability of the device is low.

On the other hand, Patent Document 7 discloses a technology of a polarized light emitting element with an order parameter of 0.81 to 0.95. Although this technology can provide a polarized light-emitting element or a polarized light-emitting plate with high brightness and high degree of polarization, its contrast is the visible display contrast (the contrast of polarized light) when a general polarizing plate is interposed, rather than based on The contrast of the light emitted by each axis of the polarized light emitting element. In other words, although Patent Document 7 can provide polarized light with high brightness and high degree of polarization, it cannot provide sufficiently high visibility in terms of the contrast of the light emitted from each axis. In view of the disadvantages of such conventional polarizing elements or polarized light-emitting elements, there is a demand for polarized light-emitting elements or polarized light-emitting panels that exhibit polarized light emission and have a high contrast of light emitted from each axis.

The purpose of the present invention is to provide a polarized light-emitting element capable of achieving high-contrast polarized light; and/or provide a polarized light-emitting element such as a liquid crystal display with high durability that can also be used in harsh environments; and/or provide a polarized light-emitting element A polarized light-emitting panel and a display device equipped with the aforementioned polarized light-emitting element.

After intensive research in order to achieve such an objective, the inventors have newly discovered that the polarized light-emitting element shown below can achieve high-contrast polarized light emission.

One aspect of the present invention is shown below, but the present invention is not limited to this aspect.

[Invention 1]

A polarized light-emitting element is provided with a substrate; wherein,

The aforementioned substrate contains at least one polarized light emitting pigment,

The aforementioned polarized light emitting pigment is oriented on the aforementioned substrate,

The aforementioned polarized light emitting element exhibits a polarizing effect in the wavelength region of the absorbed light,

Moreover, when the polarized light with the highest wavelength of the aforementioned polarization is incident, the absorbance (Abs-Ky) on the axis with the least absorption is 0.0001 to 0.12.

[Invention 2]

The polarized light-emitting element according to Invention 1, wherein when the polarized light with the highest wavelength of the polarization action is incident, the absorbance of the axis with the largest absorption (Abs-Kz) versus the absorbance of the axis with the least absorption (Abs- Ky) ratio ("Abs-Kz"/"Abs-Ky") is 10 to 200.

[Invention 3]

The polarized light-emitting element according to Invention 1 or 2, wherein the polarized light-emitting dye system has fluorescent light-emitting characteristics.

[Invention 4]

The polarized light-emitting element according to any one of Inventions 1 to 3, wherein the polarized light-emitting dye has a light-emitting characteristic capable of absorbing light in the ultraviolet region to the near-ultraviolet visible light region to emit light in the visible light region by polarized light.

[Invention 5]

The polarized light-emitting element according to any one of Inventions 1 to 4, wherein the polarized light-emitting dye has a biphenyl skeleton, a stilbene skeleton, and a coumarin skeleton in its chemical structural formula Any type of skeleton in the group.

[Invention 6]

The polarized light emitting element according to any one of Inventions 1 to 5, wherein the polarized light emitting dye is a compound represented by the following formula (1) or a salt thereof;

In the formula, L and M are each independently selected from a nitro group, an amino group which may have a substituent, a carbonylamino group which may have a substituent, a naphthotriazole group which may have a substituent, and a C which may have a substituent. _The group consisting of 1-20 alkyl groups, vinyl groups that may have substituents, amide groups that may have substituents, ureido groups that may have substituents, aryl groups that may have substituents, and carbonyl groups that may have substituents Group.

[Invention 7]

The polarized light emitting device according to any one of Inventions 1 to 6, wherein the substrate contains polyvinyl alcohol.

[Invention 8]

The polarized light emitting device according to any one of Inventions 1 to 7, wherein the substrate includes an oriented polyvinyl alcohol film.

[Invention 9]

The polarized light emitting device according to any one of Inventions 1 to 8, wherein the substrate further contains a boron compound.

[Invention 10]

A polarized light-emitting plate is provided with the polarized light-emitting element according to any one of Inventions 1 to 9 and a transparent protective layer on one or both sides of the polarized light-emitting element.

[Invention 11]

A display device is provided with the polarized light-emitting element according to any one of Inventions 1 to 9, or the polarized light-emitting plate according to Invention 10.

The polarized light-emitting element of the present invention contains a polarized light-emitting dye, and sufficiently absorbs the light of the axis to which the polarized light-emitting dye is oriented, and exhibits strong light emission by absorbing light. On the other hand, in the axis system where the polarized light-emitting dye is not oriented, the absorption of light is weak, and the light emission is weak. That is, the polarized light emitting element of the present invention has an axis of strong light emission and an axis of weak light emission, and therefore functions as an element that performs polarized light emission with different light emission intensities on each axis. This situation shows that the amount of light emitted by each axis of the polarized light-emitting element is controlled by controlling the amount of light absorbed by each axis to control the polarized light emission. For example, in a polarized light emitting element that exhibits polarized light emission in the visible light region by absorbing light in the ultraviolet region, the luminous intensity of the axis of strong polarized light emission and the luminous intensity of the axis of weak polarized light are based on the ultraviolet region of each axis. Controlled by the amount of light absorption. Here, in order to improve the contrast of polarized light-emitting elements, the strong light-emitting axis can be made stronger (that is, the light absorption of the strong light-emitting axis is increased), or the weak light-emitting axis can be made weaker (also That is, the light absorption of the weak luminous axis is reduced), thereby increasing the contrast of the luminous axis of each axis. In the contrast of light-emitting, in order to obtain a higher visibility contrast, the brightness of the strong light-emitting axis must be increased. On the other hand, how can the light emission be controlled when the light is extinct, that is, how can the weak light-emitting axis be reduced? Brightness is an important factor in improving contrast. The sensitivity of the human eye is very high, and even a very small amount of light (brightness) can be sensed. That is, in order to improve the visibility or contrast of luminescence, it is necessary to suppress luminescence during extinction.

Due to the above, the polarized light-emitting element of the present application reduces the amount of light on the axis of weak luminescence in the polarized light, and increases the amount of light on the axis of strong luminescence relative to the axis of weaker light. In this way, the contrast of the light emission of each axis is improved, so that high-contrast polarized light emission can be realized. The aforementioned polarized light emitting element fully absorbs the light of the axis with strong luminescence and strongly emits the light of that axis. On the other hand, it reduces the absorption of light of the axis with weak luminescence and reduces the amount of light emitted by the axis. With the structure of the present invention, a polarized light emitting element can be provided, It dramatically improves the contrast of polarized light and has high visibility. Furthermore, in one aspect of the present invention, it is possible to suitably provide a polarized light-emitting panel provided with the aforementioned polarized light-emitting element, and a display device provided with the aforementioned polarized light-emitting element or the aforementioned polarized light-emitting panel, especially a liquid crystal display device.

Figure 1 is a graph of Ky and Kz values for each wavelength of the polarizing plate for the ultraviolet region.

Figure 2 is a graph showing the relationship between "Abs-Ky" and "Emission CR", where "Abs-Kz" is displayed as 1.0 to 3.5, which is one of Examples 1 to 4, Example 10, and Comparative Examples 1 to 3. "Abs-Ky".

3 is a graph showing the relationship between "Abs-Kz" and "Emission CR", where "Abs-Kz" is the "Abs-Kz" in Examples 1 to 4, Example 10, and Comparative Examples 1 to 3.

In the description of this case and the scope of the patent application, "substituents" include hydrogen atoms based on convenience. The term "may have a substituent" means that it also includes the case where it does not have a substituent. For example, "phenyl which may have substituents" includes unsubstituted simple phenyl groups and substituted phenyl groups.

<Polarized light emitting element>

The polarized light-emitting element of the present invention contains at least one polarized light-emitting pigment and a substrate. The photoluminescent dye is oriented on the substrate, and the polarized light emitting element exhibits a polarizing effect in the wavelength region of the absorbed light, and when the polarized light is incident on the polarized light of the highest wavelength, the absorbance of the axis with the least absorption ( Abs-Ky) is 0.0001 to 0.12. The polarized light emitting element of the present invention can dramatically improve the contrast of polarized light emitting.

In one aspect of the present invention, the polarized light emitting element of the present invention displays polarized light emission in the visible light region by absorbing light by the above-mentioned polarized light emitting dye. In this polarized light-emitting element, the light-emission amount of the axis where polarized light emission is strong and the light-emission amount of the axis where polarized light emission is weak are controlled in accordance with the amount of light absorbed by each axis. In other words, this means that in a polarized light-emitting element that exhibits polarized light emission in the visible light region by absorbing light, the more the absorption of light in the strong light-emitting axis, the more the light emission in that axis; The more the axis of light absorption decreases, the more the axis of light emission decreases. It is shown that the polarized light-emitting element has a light-emitting axis that emits strong light, and a light-emitting axis that emits light to an imperceptible degree, which will increase the contrast of the polarized light emitted. Here, the sensitivity of human eyes is very high, and even a very weak amount of light (brightness) can be perceived. Because human eyes are highly sensitive, they can fully recognize the emitted light. On the contrary, in order to increase the contrast of the polarized light emitting element when it emits light, it is necessary to sufficiently suppress the light when it does not emit light (luminescence when it is extinct). The degree of unrecognizable. This system shows that the more the light from the strong axis of light emission to the weak axis of light emission is reduced, when the polarized light-emitting element performs polarized light emission, the more the contrast of light emission is improved.

Based on the above-mentioned research and review, it was found that in a polarized light-emitting element in which at least one polarized light-emitting pigment is oriented on the substrate, when polarized light with the highest wavelength of polarization is incident, "Abs-Ky" is 0.0001 To 0.12, this can dramatically improve the contrast of polarized light emission. By setting "Abs-Ky" to be 0.0001 to 0.12, a polarized light emitting device with high contrast can be provided, but for "Abs-Ky", it is preferably 0.0001 to 0.08, more preferably 0.0001 to 0.02, and then It is more preferably 0.0001 to 0.01, particularly preferably 0.0001 to 0.006.

Furthermore, the aforementioned polarized light emitting element exhibits a polarization effect in the wavelength region of the absorbed light, and in the wavelength where the aforementioned polarization effect is the highest, when polarized light (for example, linearly polarized light) is incident, the axis of absorption is the largest The ratio of the absorbance (Abs-Kz) to the absorbance (Abs-Ky) of the axis with the least absorption ("Abs-Kz"/"Abs-Ky") shows a value of 10 to 200, which is better due to the increased contrast. As for the ratio of "Abs-Kz" to "Abs-Ky", it is preferably 15 or more, more preferably 20 or more, still more preferably 60 or more, particularly preferably 80 or more. The upper limit is not particularly limited, but if it is more than 100, it can provide sufficient polarized light emission contrast in polarized light emission. If the ratio of "Abs-Kz" to "Abs-Ky" is 200, it can provide particularly sufficient contrast when polarized light is emitted.

In addition, the polarized light emitting element exhibits a polarization effect in the wavelength region of the absorbed light, and in the wavelength where the polarization effect is the highest, when the polarized light is incident, "Abs-Ky" is based on consideration of non-polarized light emission. It is better to obtain the absorbance measured in the state of the interface reflection of the device or the state without interface reflection. The interface reflection of polymers (such as general organic films such as thermoplastic resins) is about 4%, and the transmittance of about 8% will be lost due to the reflection at the interface between the surface and the back. Because of this, the transmittance of an organic transparent film substantially composed of a polymer is generally below 92%, and light loss occurs due to the unevenness and deformation of the surface. Assuming that there is no internal absorption in the organic film and interface reflection occurs, when the transmittance is 92%, the absorbance is about 0.036. However, the absorbance of 0.036 is a value calculated by the influence of the interface reflection and is not a polarized light-emitting pigment. Absorber. Since this value is not caused by the absorption of polarized light-emitting pigments, it is not helpful for light emission. In other words, in the case of this case, if the influence of interface reflection is considered, the absorbance of each axis when polarized light is incident will be calculated as a larger value due to the reflection of the interface. The value irrelevant to the magnitude of the absorbed light will be calculated as the absorbance. Although the ratio of the strong absorption axis of the polarized light-emitting element to the weak absorption axis of the polarized light-emitting element can be calculated even if there is interface reflection, the method of measuring the absorbance of the polarized light-emitting element in this case is based on the consideration of the non-interface reflection. State, or no interface reflection The absorbance measured in this state is preferably used as a value indicating the absorption of light that contributes to the light emission, and it can be used in a highly correlated manner with the contrast of the polarized light emitting element when the polarized light emits light. In terms of forming a state without interface reflection, a method of applying anti-reflection treatment (AR treatment) can be cited. On the other hand, in the absorbance measurement, a substrate made of substantially the same material as that of the substrate of the polarizing light-emitting element is used, and the value of absorbance obtained by the measuring device is set to absorbance zero. Thereafter, by measuring the absorbance of the polarized light-emitting element of the present invention with respect to the obtained value of zero absorbance, the absorbance measured based on a state where there is substantially no interface reflection can be measured. Alternatively, in the transmittance measurement, use a substrate made of substantially the same material as that of the substrate of the polarizing light-emitting element, and set the transmittance obtained by the measuring device to 100 at each wavelength. % Transmittance, and the obtained 100% transmittance is used as the base line. By measuring the transmittance of the polarized light-emitting element of the present invention relative to the baseline, the measurement can be based on the actual The transmittance measured in a state where there is no interface reflection, and the absorbance can be converted from the transmittance. For example, when a polyvinyl alcohol film is used as a substrate and a polarizing light-emitting dye is used to produce a polarized light-emitting element, when the absorbance is measured, the first thing that does not contain the polarized light-emitting dye is measured by the measuring device. The transmittance of each wavelength of the polyvinyl alcohol film is set to 100%, and the value of 100% is used as the reference line. After that, the transmittance of each wavelength of the polarized light emitting element of the present invention relative to the reference line is measured. The transmittance measured based on the state of substantially no interface reflection can be measured, and the absorbance can be converted from the transmittance.

Polarized light-emitting pigments capable of polarized light emission by light absorption refer to pigments that absorb specific light and emit polarized light by using the specific light, and are typically fluorescent pigments or phosphorescent light-emitting pigments. As such a dye, any one of a fluorescent dye and a phosphorescent luminescent dye can be used, but it is preferable to use a fluorescent dye. In addition, the wavelength of the light absorbed by the dye is often different from the wavelength of the light that emits light, and it is sometimes called a wavelength conversion dye. In this way, at least one of the polarized light-emitting pigments contained in the polarized light-emitting element has a fluorescent light emission The characteristics are better, especially for devices that have high transparency and can realize polarized light emission of visible light, a fluorescent light capable of at least absorbing light in the ultraviolet region to the near-ultraviolet visible region to emit light in the visible region The luminous characteristics are better. In addition, the so-called light from the ultraviolet region to the near-ultraviolet visible light region specifically refers to light with a wavelength of 300 to 430 nm. Because it is a region that cannot be seen by humans or a wavelength with significantly lower sensitivity, it is said that light of a wavelength in this range can be absorbed The use of light-emitting system means that polarized light emission can be realized with light that is invisible to the eyes. Since the wavelength of the light absorption range of the polarized light-emitting element is in the range of low visual sensitivity, it means that a high-transparency element can be obtained. The preferred ultraviolet range to near-ultraviolet visible light range that can be used in this case refers to light from 300 to 430 nm, but more preferably from 340 to 420 nm, even more preferably from 360 to 410 nm, and even more preferably from 370 to 405 nm, Particularly preferably, it is 380 to 400 nm.

In addition, by being oriented on the substrate, the polarized light-emitting dye can show the absorption anisotropy of light between the axis on which the substrate is oriented and the axis orthogonal to the axis, and can combine random light (such as natural light) Converted into polarized light. It is known that in a polarized light emitting element, when linearly polarized light is incident perpendicularly to the axis oriented by the polarized light-emitting dye, the ratio of the absorbance is relative to the case where linearly polarized light is incident on the axis oriented parallel to the polarized light-emitting dye. Two-color ratio. If the dichroic ratio is 2 or more, it means that the absorption anisotropy of the polarized light-emitting dye appears twice in the orientation axis and the axis different from the orientation axis. Therefore, a dichroic ratio of 2 or more becomes a display polarized light-emitting dye Orientation and showing an index of absorption anisotropy. In addition, if the dichroic ratio is 2 or more, it means that the polarized light-emitting dye is oriented, and the higher dichroic ratio means that the polarized light emission function is improved, and the dichroic ratio is 4 or more, more preferably 10 or more, and more Preferably it is 20 or more, particularly preferably 30 or more. The higher the dichroic ratio, the better, so there is no special upper limit. However, if the dichroic ratio is about 70, it means that it has a sufficiently high dichroic ratio, and if the dichroic ratio is 100, it means that it has a more sufficient dichroic ratio. The height of the two-color ratio.

By using one or more kinds of polarized light-emitting dyes, and the aforementioned polarized light-emitting dye is contained and aligned in the substrate, a polarized light-emitting element exhibiting polarized light emission can be obtained. So polarized Even if the light-emitting element uses one kind of polarized light-emitting dye, it can provide fully-recognizable polarized light, but it can also display various polarized light-emitting colors by adjusting the mixing ratio of a plurality of polarized light-emitting dyes. In addition, it is also possible to realize various colors by each axis by changing the amount of light emitted and the absorbance at each wavelength, and it is also possible to provide white as the luminous color.

<Polarized Luminescent Pigment>

The polarizing luminescent pigment is preferably a compound or salt thereof having any one of the skeletons selected from the group consisting of a biphenyl skeleton, a stilbene skeleton, and a coumarin skeleton in its chemical structural formula, especially, more preferably A compound having a stilbene skeleton or a biphenyl skeleton or a salt thereof. The polarized light-emitting pigment system with such a basic skeleton can display fluorescent light-emitting characteristics and emit light with high contrast during light-emitting. The stilbene skeleton, coumarin skeleton, or biphenyl skeleton, which are the basic skeletons of polarized light-emitting pigments, each skeleton itself exhibits fluorescent luminescence characteristics, and has high dichroism by being oriented on the substrate The role. Since this effect is due to the structure of each basic skeleton of the stilbene skeleton, biphenyl skeleton, or coumarin skeleton, any substituents can be further bonded to the basic skeleton structure. However, when the basic skeleton structure replaces the azo group, it is like a conventional dye-based polarizer. Although a high degree of polarization can be achieved, the amount of light emitted will be significantly reduced depending on the position where the azo group is substituted. A situation where the desired amount of luminous light is obtained. Therefore, when each basic skeleton replaces the azo group, its substitution position is important. The polarized light-emitting dye system may be used alone or in combination of two or more kinds.

As described above, the polarized light-emitting dye has a fluorescent light-emitting characteristic capable of polarizing light in the visible light region by absorbing light in the ultraviolet region to the near-ultraviolet visible light region, and is therefore preferred. Specifically, it is preferable to display polarized light emission in the visible light region of 400 to 780 nm by irradiating light in the ultraviolet region of 400 nm or less and the near ultraviolet visible light region of 400 to 430 nm after the substrate contains and oriented a polarized light emitting dye. In addition, although ultraviolet light generally shows light in the wavelength region below 400nm, for the wavelength region below 430nm The human visual perception of Territory Light is also obviously low. Therefore, light from the ultraviolet region to the near-ultraviolet visible light region can be defined as light that cannot be seen by human eyes. For example, light in the wavelength region of 300 to 430 nm can be used as the absorbed light for the polarized light-emitting element of the present invention to absorb. Even if the polarized light-emitting pigment is a compound or salt thereof having any one of the skeletons selected from the group consisting of a phenyl skeleton, a stilbene skeleton, and a coumarin skeleton in its chemical structural formula, it is preferably used in this case The light from the ultraviolet region to the near-ultraviolet visible light region also refers to the light of 300 to 430nm, more preferably 340 to 420nm, still more preferably 360 to 410nm, still more preferably 370 to 405nm, particularly preferably 380 to 400nm, so The light is preferable because it can obtain a polarized light-emitting element that absorbs light that is invisible to the eye and can emit light in a polarized light.

(a) Polarized light-emitting pigments with stilbene skeleton

The polarizing 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 are each independently selected from a nitro group, an optionally substituted amino group, an optionally substituted aminocarbonyl group (carbonyl amide group), and an optionally substituted naphtho group. Triazole group, optionally substituted C _1-20 (carbon number 1 to 20) alkyl group, optionally substituted vinyl group, optionally substituted amide group (carbonylamino group and sulfonylamino group) ), but not limited to the group consisting of optionally substituted ureido groups, optionally substituted 5- to 20-membered ring aryl groups, and optionally substituted carbonyl groups. The compound having a stilbene skeleton represented by the formula (1) exhibits fluorescent light emission, and can obtain dichroism by aligning it. However, since the luminescence properties are derived from the stilbene skeleton, the azo group, which is suspected of adversely affecting its luminescence properties, is not suitable as L and M, but may be an azo group.

Examples of the amino group that may have a substituent include: unsubstituted amino; methylamino, ethylamino, n-butylamino, tertiary butylamino, n-hexylamino, dodecylamine group, dimethylamino, diethylamino, di - n-butyl amine, methyl ethyl amine, ethyl hexyl amine and the like may have a substituent group of _1-20 C alkyl group; phenyl A 5- to 12-membered ring arylamino group which may have a substituent, such as an amino group, a diphenylamino group, a naphthylamino group, an N-phenyl-N-naphthylamino group, and the like. The aforementioned "5- to 12-membered ring aryl group" may contain one to three heteroatoms independently selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom as the ring constituent atoms.

Examples of the aminocarbonyl (carbonylamido) system that may have a substituent include: N-methyl-aminocarbonyl (-CONHCH ₃ ), N-ethyl-aminocarbonyl (-CONHC ₃ H ₅ ), N -Phenyl-aminocarbonyl (-CONHC ₆ H ₅ ) and the like.

Examples of the "C _{1-20 alkyl" system of the C 1-20} alkyl group which may have a substituent include: methyl, ethyl, n-butyl, n-hexyl, n-octyl, n-dodecyl and other linear C _1-12 alkyl, isopropyl, second butyl, tertiary butyl and other branched chain C _3-10 alkyl, cyclohexyl, cyclopentyl and other cyclic C _3-7 alkyl Wait. Among these, a straight-chain or branched-chain alkyl group is preferred, and a straight-chain alkyl group is more preferred.

Examples of vinyl groups that may have substituents include: ethenyl, styryl, _{vinyl having C 1-20} alkyl, vinyl having C _1-20 alkoxy , Divinyl, pentadienyl, etc.

Examples of the amide group (carbonylamino group and sulfonylamino group) that may have a substituent include: acetamido (methylcarbonylamino) (-NHCOCH ₃ ), ethylcarbonylamino, n-butyl _{-C 1-20} alkylcarbonylamino group which may have substituents such as carbonylamino group; benzamide group (phenylcarbonylamino group) (-NHCOC ₆ H ₅ ), biphenylcarbonylamino group , Naphthylcarbonylamino group, 5 to 12-membered ring arylcarbonylamino group, methylsulfonylamino group, ethylsulfonylamino group, propylsulfonylamino group, n-butyl group which may have substituents _{-C 1-20} alkyl sulfonyl amine groups, such as sulfonyl sulfonyl amine groups, phenyl sulfonyl amine groups, naphthyl sulfonyl amine groups, etc., which may have substituents such as 5 to 12-membered ring aryl sulfonyl sulfonyl groups Amine group and so on. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

Examples of the ureido group that may have a substituent include: a mono-C _1-20 alkyl ureido group, a di-C _1-20 alkyl ureido group, a single 5- to 12-membered ring aryl urea group, and a 5- to 12-membered ring aromatic group. Base urea group and so on. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

Examples of the "5- to 20-membered ring aryl group" of the 5- to 20-membered ring aryl group that may have a substituent include: phenyl, naphthyl, anthryl, biphenyl, etc., preferably 5 to 12-membered ring aryl base. The aryl group may contain 1 to 3 heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms and sulfur atoms as the ring constituent atoms of 5 to 12 members, preferably 5 or 6 members. Ring base. 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 particularly preferred.

_{Examples of the carbonyl system that may have a substituent include C 1-20} alkylcarbonyl groups such as methylcarbonyl, ethylcarbonyl, and n-butyl-carbonyl, and 5- to 12-membered ring arylcarbonylamino groups such as phenylcarbonyl. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

Each of the above-mentioned substituents may further have a substituent. The above-mentioned substituents or the substituents that the above-mentioned substituents can have are not particularly limited, but examples include: nitro, cyano, hydroxyl, sulfonic acid, phosphoric acid, carboxyl, and optionally substituted Amino groups (the same definitions as the amine groups that may have substituents for L and M in the above formula (1)), acyloxy groups, halogen atoms, alkoxy groups, aryloxy groups, and the like.

_{Examples of the acyloxy group include C 1-20} acyloxy groups such as a methylcarboxyl group and an ethylcarboxyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkoxy group include C _1-20 alkoxy groups such as methoxy, ethoxy, and propoxy. Examples of the aryloxy group include 5- to 12-membered ring aryloxy groups such as phenoxy and naphthoxy. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

The compound represented by formula (1) includes, for example, Kayaphor series (manufactured by Nippon Kayaku Co., Ltd.), Whitex series (manufactured by Sumitomo Chemical Co., Ltd.), such as Whitex RP. In addition, the following are examples of compounds represented by formula (1), but are not limited to these.

As for other compounds having a stilbene skeleton, the compound represented by the following formula (2) or formula (3) or a salt thereof is preferred. By using these compounds, you can also get Polarized light emitting element with more vivid white light. Furthermore, the compounds represented by the following formulas (2) and (3) also exhibit fluorescence emission due to the stilbene skeleton, and can obtain dichroism by aligning them.

In the above formula (2), X represents a nitro group or an amine group which may have a substituent. The amine group that may have a substituent has the same definition as the amine group that may have a substituent in the above formula (1). Among these, X is preferably a nitro group, a C _1-20 alkylcarbonylamino group which may have a substituent, a 5- to 12-membered ring arylcarbonylamino group which may have a substituent, and a C _1-20 alkylsulfonyl group. An acylamino group or a 5- to 12-membered ring arylsulfonylamino group which may have a substituent, and in particular, a nitro group is more preferred. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

In the above formula (2), R represents a halogen atom such as a hydrogen atom, a chlorine atom, a bromine atom, or a fluorine atom, a hydroxyl group, a carboxyl group, a nitro group, an optionally substituted alkyl group, an optionally substituted alkoxy group, Or an amine group that may have a substituent. The alkyl group which may have a substituent has the same definition as _{the C 1-20} alkyl group which may have a substituent in the above formula (1). Preferred examples of the alkoxy group that may have a substituent include C _1-20 alkoxy groups such as a methoxy group and an ethoxy group. The optionally substituted amine group has the same definition as the optionally substituted amine group in the above formula (1), preferably methylamino, dimethylamino, ethylamino, diethyl Amino, or phenylamino, etc. R may be bonded to any carbon atom of the naphthalene ring in the naphthotriazole ring, but when the carbon atoms condensed with the triazole ring are used as position 1 and 2, R is bonded to position 3 and 5. Bits or 8 bits are preferred. Among these, R is preferably a hydrogen atom or a C _1-20 alkyl group, and when R is a C _1-20 alkyl group, a methyl group is preferred.

In the above formula (2), n is an integer of 0 to 3, and 1 is preferred. In addition, in the above formula (2), -(SO ₃ H) may be bonded to any carbon atom of the naphthalene ring in the naphthotriazole ring. Regarding the substitution position of -(SO ₃ H) in the naphthalene ring, when the carbon atoms condensed with the triazole ring are taken as position 1 and position 2, if n=1, the aforementioned substitution position is taken as position 4. , 6 or 7 is preferred; if n=2, the aforementioned substitution position is preferably 5 and 7, or 6 and 8; if n=3, the aforementioned substitution is 3 Bits, 6 bits and 8 bits are preferable. Among these, R is a hydrogen atom, and n being 1 or 2 is particularly preferred.

In the formula (3), Y represents a C _1-20 alkyl group which may have a substituent, a vinyl group which may have a substituent, or a 5- to 12-membered ring aryl group which may have a substituent. Among these, a 5- to 12-membered ring aryl group which may have a substituent is preferred, a naphthyl group which may have a substituent is more preferred, and a naphthyl group substituted with an amine group and a sulfo group is a substituent. Especially good. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

In the formula (3), Z is the same as X in the above formula (2), and represents a nitro group or an amine group that may have a substituent, and a nitro group is preferred.

(b) Polarized luminescent pigment with biphenyl skeleton

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 represent a nitro group, an optionally substituted amino group, an optionally substituted aminocarbonyl group (carbonylamino group), and an optionally substituted naphthotriazole A group, a C _1-20 alkyl group that may have a substituent, a vinyl group that may have a substituent, an amide group (a carbonylamino group and a sulfonylamino group) that may have a substituent, a ureido group that may have a substituent, Although it may have a 5- to 12-membered ring aryl group which may have a substituent, or a carbonyl group which may have a substituent, it is not limited to these. However, when P and/or Q is an azo group, it is less suitable because the fluorescence emission will be significantly reduced, but it may be an azo group. The aforementioned "5- to 12-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

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

In the above formula (5), j independently represents an integer from 0 to 2. In addition, in terms _{of the position where -(SO 3} H) is bonded, when the carbon atom bonded by -CH=CH- is taken as the 1-position, the 2-position, 4-position, and 6-position are preferred, and 4 are particularly good.

In the above formula (5), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a C _1-4 alkyl group, a C _1-4 alkoxy group, an aralkoxy group, an alkenoxy group , C _1-4 alkylsulfonyl, 5 to 20-membered ring arylsulfonyl, carbamido, sulfonamido, carboxyalkyl. The position where R ¹ to R ⁴ are bonded is not particularly limited, but when the vinyl group is used as the 1-position, the 2-position, the 4-position, and the 6-position are preferred, and the 4-position is particularly preferred.

Examples of the C _1-4 alkyl system include methyl, ethyl, propyl, n-butyl, second butyl, tertiary butyl, cyclobutyl, and the like.

Examples of the C _1-4 alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a second butoxy group, a tertiary butoxy group, and a cyclobutoxy group.

The aralkoxy system includes, for example, a C _7-18 aralkoxy group. One to three carbon atoms in the aforementioned aralkoxy group can be independently replaced with heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms.

Examples of the alkenyloxy group include C _1-18 alkenyloxy group and the like.

Examples of the C _1-4 alkylsulfonyl group include methylsulfonyl, ethylsulfonyl, propylsulfonyl, n-butylsulfonyl, second butylsulfonyl, and tertiary butylsulfonyl. Sulfonyl, cyclobutyl sulfonyl and the like.

Examples of the 5- to 20-membered ring arylsulfonyl group include phenylsulfonyl, naphthylsulfonyl, and biphenylsulfonyl. The aforementioned "5- to 20-membered ring aryl group" may include 1 to 3 heteroatoms independently selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms as ring constituent atoms.

The compound represented by the above formula (4) or formula (5) can be produced by a known method. For example, the compound represented by formula (5) can be synthesized by condensing 4-nitrobenzaldehyde-2-sulfonic acid with a phosphonate, and then reducing the nitro group. Specific examples of the compound represented by the formula (5) include, for example, the following compounds described in Japanese Patent Application Laid-Open No. 4-226162 and the like.

(c) Polarized luminescent pigment with coumarin skeleton

The compound having a coumarin skeleton that becomes a polarized light-emitting pigment is preferably represented by the following formula (6) The compound or its salt.

In formula (6), A system represents a coumarin-based compound which may have a substituent, X represents a sulfo group or a carboxyl group, and p represents an integer of 1 to 3. The coumarin-based compound represented by the formula (6) is a polarizing luminescent pigment having a coumarin skeleton and exhibiting water solubility.

When the above formula (6) is the following formula (6-2), the contrast system at the time of polarized light emission is more improved, so it is a preferable example. In formula (6-2), groups R ⁵ and R ⁶ each independently represent a C _1-10 hydrocarbon group, Q represents a sulfur atom, an oxygen atom, or a nitrogen atom, and q represents an integer of 1 to 3.

As described above, in the present invention, the water-soluble coumarin-based compound represented by formula (6) or formula (6-2) has at least one coumarin skeleton in its molecule. The A system of the formula (6) may have an azo bond like a conventional dichroic dye, but it may also have a form that does not have an azo bond like the above formula (6-2). Since the polarized light emitting pigment of the water-soluble coumarin-based compound of the present invention has a coumarin skeleton, it exhibits a polarized light emission effect by irradiating ultraviolet light and visible light (specifically, light of 300 to 600 nm).

The so-called salt of the compounds represented by formulas (1) to (6-2) means the state in which the free acid of each compound represented by the above formulas forms a salt together with an inorganic cation or an organic cation. Examples of inorganic cations include various cations of alkali metals (for example, lithium, sodium, potassium, etc.), ammonium (NH ₄ ⁺ ), and the like. Moreover, as an organic cation system, the organic ammonium represented by following formula (D) etc. are mentioned, for example.

In formula (D), 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 a group other than a hydrogen atom .

Specific examples of Z ¹ to Z ⁴ _{include, for example, C 1-6} alkyl groups such as methyl, ethyl, butyl, pentyl, and hexyl, preferably C _1-4 alkyl; hydroxymethyl, 2- _{Hydroxy C 1-6} alkyl groups such as hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, etc., preferably hydroxy C _1-4 Alkyl; and hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl and other hydroxy C _{1 The -6} alkoxy C _1-6 alkyl group is preferably a hydroxy C _1-4 alkoxy C _1-4 alkyl group and the like.

Among these inorganic cations or organic cations, sodium, potassium, lithium, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, ammonium and other cations are more preferred. Preferably, each inorganic cation of lithium, ammonium or sodium is particularly preferred.

The polarized light-emitting dye having the above-mentioned structure preferably does not have an azo group in the molecule, so that the absorption of light due to azo bonding is suppressed. In particular, compounds having a stilbene skeleton exhibit luminescence due to the irradiation of ultraviolet light, and the molecules are stabilized due to the presence of the strong carbon-carbon double bond of the stilbene skeleton. Therefore, the polarized light-emitting element including the polarized light-emitting dye having such a specific structure can absorb light, and use the energy of the absorbed light to exhibit a polarized light emission effect in the visible light region.

(Other pigments)

The polarized light emitting element exhibiting the above characteristics may further include at least one fluorescent dye and/or organic dye that is different from the above polarized light emitting pigment within a range that does not hinder the polarization performance of the polarized light emitting element. Examples of the aforementioned fluorescent dye system include: C.I. Fluorescent Brightener 5. C. I.Fluorescent Brightener 8, C.I.Fluorescent Brightener 12, C.I.Fluorescent Brightener 28, C.I.Fluorescent Brightener 30, C.I.Fluorescent Brightener 33, C.I.Fluorescent Brightener 350, C.I.Fluorescent Brightener 360, C.I.Fluorescent Brightener 365, etc.

Examples of the above-mentioned organic dyes include: CIDirect Yellow 12, CIDirect Yellow 28, CIDirect Yellow 44, CIDirect Orange 26, CIDirect Orange 39, CIDirect Orange 71, CIDirect Orange 107, CIDirect Red 2, CIDirect Red 31, CIDirect Red 79, CIDirect Red 81, CIDirect Red 247, CIDirect Blue 69, CIDirect Blue 78, CIDirect Green 80, and CIDirect Green 59, etc. These organic dyes may be free acids, or alkali metal salts (such as Na salt, K salt, Li salt), ammonium salt, or amine salt.

<Substrate>

The polarized light-emitting element is provided with a substrate that can contain polarized light-emitting pigments and can be oriented. The substrate preferably contains a hydrophilic polymer, which adsorbs polarized light-emitting dye, contains a boron compound and can be cross-linked; preferably, it is a hydrophilic polymer obtained by forming a film of the hydrophilic polymer. Polymer membranes, especially oriented hydrophilic polymer membranes. The hydrophilic polymer that can be used is not particularly limited, but for example, polyvinyl alcohol-based resins and starch-based resins are preferred. From the viewpoints of the dyeability, processability, and crosslinking properties of the polarized light-emitting dye, the hydrophilic polymer preferably contains a polyvinyl alcohol-based resin or a derivative thereof, and more preferably contains polyvinyl alcohol. Examples of the polyvinyl alcohol-based resin or its derivatives include: polyvinyl alcohol or its derivatives, and any one of polyvinyl alcohol or its derivatives with olefins such as ethylene, propylene, crotonic acid, acrylic acid, and methacrylic acid. And maleic acid, unsaturated carboxylic acid and other modified resins. In terms of the adsorptivity and orientation of the polarized light-emitting dye, among these, the base material is preferably a film made of polyvinyl alcohol or its derivatives.

Hereinafter, a method of adsorbing and aligning a polarizing light-emitting dye using a substrate containing a polyvinyl alcohol-based resin is exemplified. The base material system containing a polyvinyl alcohol-type resin can use a commercial item, for example, and can also be produced by film-forming a polyvinyl alcohol-type resin. The method for forming polyvinyl alcohol-based resin films is not particularly limited. For example, a method of melt-extruding water-containing polyvinyl alcohol, a flow cloth film method, a wet film method, and a gel film method (using polyethylene After the aqueous alcohol solution is temporarily cooled and gelled, the solvent is extracted and removed), the casting film method (flowing and drying the polyvinyl alcohol aqueous solution on the base plate), and a combination of these methods are well-known film forming methods. The thickness of the substrate can be appropriately designed, but is usually 10 to 100 μm, preferably 20 to 80 μm.

In addition, the base material preferably further contains a boron compound. In particular, it is preferable to contain the boron compound substantially uniformly in the thickness direction (depth direction from the surface) of the substrate, that is, the concentration of the boron compound contained in the substrate has almost no difference between the surface and the center of the substrate. Examples of the boron compound system include inorganic compounds such as boric acid, borax, boron oxide, and boron hydroxide; boric acid, alkenyl boric acid, aryl boric acid, alkyl boric acid, boric acid esters, trifluoroborate esters or salts thereof, etc., Boric acid and borax are preferred, and boric acid is particularly preferred. By containing the boron compound at a higher concentration from the film thickness direction of the substrate to the center portion, the contrast of the polarized light emission of the polarized light-emitting device can be further improved. Furthermore, by containing the boron compound in the base material up to the center portion, it is possible to impart higher durability to the polarized light-emitting element.

<Manufacturing method of polarized light emitting element>

The manufacturing method of the polarized light-emitting element is not limited to the following manufacturing method, but it is mainly suitable to orient the above-mentioned polarized light-emitting dye using a film made of polyvinyl alcohol or its derivative. Hereinafter, the method of manufacturing the polarized light emitting element will be explained by taking the case of using polyvinyl alcohol or its derivatives as an example.

The manufacturing method of the polarized light emitting element includes the following steps: a step of preparing a substrate; a swelling step: immersing the substrate in a swelling liquid to make the substrate swell; and a dyeing step, The swelled substrate is immersed in a dyeing solution containing more than one of the above-mentioned polarized luminescent pigments to make the substrate adsorb the polarized luminescent pigment; the cross-linking step is to immerse the substrate with the polarized luminescent pigment adsorbed in the boric acid In the solution, the polarized light-emitting pigment is cross-linked in the substrate; the extension step is to uniaxially extend the substrate with the polarized light-emitting pigment cross-linked in a certain direction, so that the polarized light-emitting pigment is arranged in a certain direction; And the drying step performed as needed is a washing step of washing the stretched substrate with a washing liquid and/or a drying step of drying the washed substrate.

(Swelling step)

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

(Dyeing step)

At least one polarized luminescent dye is impregnated and adsorbed on the substrate obtained by the swelling treatment in the swelling step. The dyeing step is not particularly limited as long as it is a method of impregnating and adsorbing a polarizing luminescent dye to the substrate. For example, a method of immersing the substrate in a dyeing solution containing a polarizing dye; coating the dyeing solution on the substrate and How to make it adsorb, etc. Among these, a method of immersing in a dyeing solution containing a polarizing luminescent dye is preferable. The concentration of the polarized luminescent pigment in the dyeing solution is not particularly limited as long as the concentration of the polarized luminescent pigment is sufficiently absorbed in the substrate. For example, 0.0001 to 1% by mass in the dyeing solution is preferable, and 0.001 to 0.5% by mass For better. In the above-mentioned polarized light emitting element, the adjustment of the dye concentration is important, and it is better to reduce the dye concentration within a range that does not impair the polarized light emission performance. In terms of improving the orientation, it is preferable to include 0.001 mass in the dyeing solution. % Or more and 0.05 mass% or less, more preferably 0.005 mass% or more and 0.04 mass% or less.

The temperature of the dyeing solution in the dyeing step is preferably from 5 to 80°C. 20 to 50°C is more preferred, and 40 to 50°C is particularly preferred. The time for immersing the substrate in the dyeing solution is preferably adjusted between 1 and 20 minutes, and more preferably between 2 and 10 minutes.

The polarized light-emitting pigments contained in the dyeing solution may be used alone, or two or more of them may be used in combination. The above-mentioned polarized light-emitting dyes have different light-emitting color systems depending on the compound. Therefore, the generated light-emitting colors can be appropriately adjusted to various colors by making the substrate contain two or more of the above-mentioned polarized light-emitting dyes. In addition, if necessary, the dyeing solution may further contain one or more organic dyes and/or fluorescent dyes that are different from the polarized light-emitting dye.

When fluorescent dyes and/or organic dyes are used in combination, in order to adjust the polarized light-emitting element to a desired color, it is possible to select the dyes to be blended, and to adjust the blending ratio, etc. According to the purpose of preparation, the mixing ratio of fluorescent dyes or organic dyes is not particularly limited, but generally speaking, relative to 100 parts by mass of polarized light-emitting dyes, the total amount of these fluorescent dyes and/or organic dyes is between 0.01 and 10 It is better to use the range of parts by mass.

Furthermore, in addition to the above-mentioned dyes, dyeing auxiliaries can be further used in combination as needed. Examples of the dyeing auxiliary system include sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulfate (glauber's salt), anhydrous sodium sulfate, and sodium tripolyphosphate, and sodium sulfate is preferred. The content of the dyeing auxiliary agent can be arbitrarily adjusted by the above-mentioned immersion time, temperature during dyeing, etc. according to the dyeability of the dichroic pigment used, but 0.0001 to 10% by mass in the dyeing solution is preferable. It is more preferably 0.0001 to 2% by mass.

After the above-mentioned dyeing step, in order to remove the dyeing solution adhering to the surface of the substrate in this dyeing step, an optional preliminary washing step may be performed. By performing the preliminary cleaning step, the polarized light-emitting pigment remaining on the surface of the substrate can be prevented from moving into the liquid for subsequent processing. In the preliminary washing step, water is generally used as the washing liquid. The cleaning method is preferably to immerse the dyed substrate in a cleaning solution. On the other hand, it can also be cleaned by coating the substrate with a cleaning solution. The washing time is not particularly limited, but is preferably 1 to 300 seconds, more preferably 1 to 60 seconds. The temperature of the cleaning solution in the preliminary cleaning step must be a temperature that does not dissolve the material constituting the substrate. Generally speaking, the cleaning treatment is performed at 5 to 40°C. Moreover, even if there is no step of the preliminary cleaning step, the performance of the polarizing element will not be particularly affected, so the preliminary cleaning step can be omitted.

(Crosslinking step)

After the dyeing step or the preliminary washing step, the base material may contain a crosslinking agent. The method for making the base material contain the crosslinking agent is preferably to immerse the base material in a treatment solution containing the crosslinking agent. On the other hand, the treatment solution may also be applied or applied to the base material. As the crosslinking agent in the treatment solution, for example, a solution containing a boron compound is used. Examples of the boron compound system include inorganic compounds such as boric acid, borax, boron oxide, and boron hydroxide, and boric acid such as alkenyl boronic acid, aryl boronic acid, alkyl boronic acid, boric acid ester, trifluoroborate or its salt, etc. Boric acid and borax are preferred, and boric acid is particularly preferred. The solvent in the treatment solution is not particularly limited, but water is preferred. The concentration of the boron compound 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, more preferably 40 to 75°C. In addition, the processing time of the cross-linking step is preferably 30 seconds to 10 minutes, and more preferably 1 to 6 minutes. By performing this cross-linking step, the obtained polarized light-emitting device shows a higher contrast. In this case, the function of the boron compound used for the purpose of improving water resistance or light penetration in the conventional technology is an excellent effect that cannot be expected at all. Moreover, in the cross-linking step, an aqueous solution containing a cation and/or a cationic polymer compound may be further combined for a fixation treatment as needed. The so-called cation refers to metal-derived ions such as sodium, potassium, calcium, magnesium, aluminum, iron, and barium, and divalent ions are preferably used. Specifically, it is calcium chloride, magnesium chloride, iron chloride, barium chloride, and the like. Through the fixation treatment, the polarized light-emitting dye in the substrate can be fixed. In this case, cationic polymer compounds are used, for example: dicyanide compounds, polyamine compounds, polycationic compounds, dimethyldiallylammonium chloride/dioxide ion copolymer, diallylamine salt Polymer, chlorinated dimethyl diallyl Base ammonium polymer, polymer of allyl amine salt, dialkylamino ethyl acrylate quaternary salt polymer, etc. Examples of the dicyanide compound series include polycondensates of dicyanamide and formalin. Examples of the polyamine compound system include polycondensates of dicyandiamide and ethylenetriamine. Examples of the polycationic compound include epichlorohydrin/dimethylamine addition polymer.

(Extension step)

After performing the above-mentioned cross-linking step, an extension step is performed. The stretching step is performed by uniaxially stretching the substrate in a certain direction. The extension method may be either a wet extension method or a dry extension method. In order to obtain a high polarization luminescence contrast, the stretch magnification of the substrate is preferably 3.0 to 9.0 times, more preferably 3.3 to 8.5 times, still more preferably 3.5 to 8.0 times, and particularly preferably 4.0 to 8.0 times . In the above-mentioned polarized light emitting element, it is preferable to reduce the film thickness after stretching in terms of improving the directivity, and the stretching magnification is more than 5.0 times and 8.0 times or less.

In the above-mentioned wet stretching method, it is preferable to stretch the substrate in water, a water-soluble organic solvent, or a mixed solution thereof. It is more preferable to perform the stretching treatment while immersing the substrate in a solution containing at least one crosslinking agent. The cross-linking agent is, for example, a boron compound that can be used in the above-mentioned cross-linking agent step, and preferably can be extended in the treatment solution used in the cross-linking step. The extension temperature is preferably 40 to 65°C, more preferably 45 to 60°C. The extension time is usually 30 seconds to 20 minutes, preferably 2 to 7 minutes. The wet extension step can implement one-stage extension or multi-stage extension with more than two stages. In addition, the elongation treatment can be optionally performed before the dyeing step. In this case, the orientation of the polarized light-emitting dye can also be performed 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 with the temperature of the air medium at room temperature to 180°C. In addition, the humidity is preferably in an atmosphere of 20 to 95% RH. The heating method of the base material includes, for example, an inter-roll zone stretching method, a roll heating stretching method, a hot press stretching method, an infrared heating stretching method, etc., but it is not limited to these stretching methods. The dry extension step can be implemented in one-stage extension or two-stage extension. Multiple extensions above the stage are implemented. In the dry stretching step, the substrate containing the polarizing luminescent dye may be stretched while containing a boron compound, or the substrate may be stretched after containing the boron compound, so that the substrate contains boron. It is better to perform the extension treatment after the compound. The temperature for applying the boron compound 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 treatment time of dry stretching is preferably from 1 to 15 minutes, more preferably from 2 to 12 minutes, and even more preferably from 3 to 10 minutes.

(Washing step)

After the above-mentioned extension step is performed, because the crosslinking agent may precipitate or foreign matter adheres to the surface of the substrate, a cleaning step for cleaning the surface of the substrate can be performed. The washing time is preferably 1 second to 5 minutes. The cleaning method is preferably to immerse the substrate in a cleaning solution. On the other hand, it is also possible to clean the substrate by coating or applying the cleaning solution to the substrate. The washing liquid is preferably water. The washing treatment can be carried out in one stage or in multiple stages with more than two stages. The temperature of the cleaning solution in the cleaning step is not particularly limited, but is usually 5 to 50°C, preferably 10 to 40°C, and may also be room temperature.

In addition to the above-mentioned water, as the solvent of the solution or treatment liquid used in the above-mentioned steps, for example, alcohols, amines, etc. can be cited. Examples of alcohols include: dimethyl sulfoxide, N-methylpyrrolidone, methanol, ethanol, propanol, isopropanol, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, Tetraethylene glycol and trimethylolpropane, etc. Examples of the amine system include ethylenediamine and diethylenetriamine. The solvent of the solution or treatment liquid is not limited to these, but water is most preferable. Moreover, the solvent system of these solutions or processing liquids may be used individually by 1 type, and may mix and use 2 or more types.

(Drying step)

After the above-mentioned washing step, a drying step of the substrate is carried out. Although drying can be done naturally Drying is performed, but in order to further improve drying efficiency, it can be performed by roller compression and surface moisture removal by air knives or suction rollers, etc. Furthermore, air drying can also be performed. The temperature of the drying treatment is preferably 20 to 100°C, more preferably 60 to 100°C. The drying time is preferably 30 seconds to 20 minutes, more preferably 5 to 10 minutes.

By the above-mentioned manufacturing method, the polarized light-emitting device of the present invention can be manufactured, and the obtained polarized light-emitting device has high durability and exhibits high-contrast polarized light emission when emitting light.

In order to increase the transmittance of the film, the polarized light-emitting element preferably utilizes the energy obtained by light absorption (especially the absorption of light from the ultraviolet region to the near-ultraviolet visible light region) to display polarized light emission in the visible light region. That is, the polarized light-emitting element has visible light absorption, which means that the transmittance is reduced or colored, etc. Therefore, the absorption band region of the polarized light-emitting element preferably has light absorption from the ultraviolet region to the near-ultraviolet visible light region. In addition, in order to further improve the brightness of the polarized light emission, it is preferable that the polarized light emission exhibits high transparency and high contrast. The light emitted by the polarized light-emitting element is polarized light in the visible light region. Therefore, when viewing the polarized light-emitting element through a general polarizer that has a polarization function for the light in the visible light region, you can view the polarized light by changing the angle of the axis of the polarizer. Polarized light emission and non-luminescence, but the degree of polarization of the polarized light emitted by the polarized light-emitting element can generally be measured by a method called the Stokes parameter method. The measurement of the degree of polarization of the polarized light of the emitted light by the Stokes parameter method can be measured, for example, by a spectropolarimeter Poxi-Spectra manufactured by Tokyo Instruments. Preferably, the degree of polarization of the polarized light capable of emitting light is, for example, 70% or more, more preferably 80% or more, still more preferably 90% or more, still more preferably 95% or more, and particularly preferably 99% or more. In addition, the higher the contrast system during polarized light emission, the better, but the higher the degree of polarization during polarized light emission, the higher the contrast during light emission can be provided. Therefore, the higher the degree of polarization during light emission is preferable. The transmittance of light in the visible light region of the polarized light-emitting element is better with high transparency, that is, the higher transmittance is better, and the visual sensitivity is modified. The positive transmittance is, for example, 60% or more, preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, particularly preferably 90% or more. Preferred is a polarized light emitting pigment having a stilbene skeleton, a coumarin skeleton, or a biphenyl skeleton, especially because the polarizing light emitting element containing a polarizing light emitting pigment having a stilbene skeleton or a biphenyl skeleton emits high The light of transparency and high degree of polarization, so in the non-luminous state or in the low-luminance axis, the absorption in the visible light region will be reduced, thereby obtaining a highly transparent polarized light-emitting element.

[Polarized light-emitting board]

The polarized light-emitting plate according to the present invention preferably includes the above-mentioned polarized light-emitting element, and a transparent protective layer provided on one or both sides of the polarized light-emitting element. Such a transparent protective layer is used to improve the water resistance and handling properties of the polarized light-emitting device. Therefore, such a transparent protective layer is preferably one that does not have any influence on the polarization effect shown by the polarized light emitting device of the present invention. However, when the polarized light-emitting element absorbs light in the ultraviolet region and exhibits polarized light emission, the transparent protective layer preferably does not have an ultraviolet light absorbing function, especially a transparent protective layer that does not have an ultraviolet light absorbing function.

The transparent protective layer is preferably a transparent protective film or a film having excellent optical transparency and mechanical strength. In addition, the transparent protective layer is preferably a film having a layer shape that can maintain the shape of the polarized light emitting element, and a film having excellent thermal stability and moisture shielding properties in addition to transparency and mechanical strength is preferred. . Examples of materials forming such a transparent protective layer include: cellulose acetate film, acrylic film, fluorine film such as tetrafluoroethylene/hexafluoropropylene copolymer, or polyester resin, polyolefin For a film composed of a resin or a polyamide-based resin, it is preferable to use a triacetyl cellulose (TAC) film, or an acrylic film, a polyethylene terephthalate film, or a cycloolefin-based film. The thickness of the transparent protective layer is preferably in the range of 1 to 200 μm, more preferably in the range of 10 to 150 μm, and particularly preferably in the range of 20 to 100 μm. The method of manufacturing the polarized light-emitting plate is not particularly limited, but for example, a transparent protective layer can be superimposed on the polarized light-emitting element and an adhesive is used to make it. Lamination and other well-known recipes are used for lamination to produce a polarizing light-emitting panel.

The polarized light-emitting plate can be further provided with an adhesive layer for bonding the transparent protective layer to the polarized light-emitting element between the transparent protective layer and the polarized light-emitting element. The adhesive constituting the adhesive layer is not particularly limited, but examples include polyvinyl alcohol-based adhesives, urethane emulsion-based adhesives, acrylic-based adhesives, polyester-isocyanate-based adhesives, etc. Preferably, polyethylene is used Alcohol-based adhesive. After the transparent protective layer and the polarized light-emitting element are bonded by an adhesive, they can be dried or heat-treated at an appropriate temperature to produce a polarized light-emitting plate.

In addition, the polarized light-emitting plate can be appropriately provided with various known functional layers such as an anti-reflection layer, an anti-glare layer, and a further transparent protective layer on the exposed surface of the transparent protective layer. When making such a layer with various functions, it is preferable to apply various functional materials to the exposed surface of the transparent protective layer. On the other hand, it is also possible to pass the layer or film with such functions through an adhesive Or the adhesive is attached to the exposed surface of the transparent protective layer.

Furthermore, the transparent protective layer system includes, for example, protective layers such as acrylic, urethane, and polysiloxane hard coat layers. In addition, in order to further improve the monomer transmittance, an anti-reflection layer can also be provided on the exposed part of the transparent protective layer. The anti-reflection layer can be formed, for example, by vapor-depositing or sputtering a substance such as silicon dioxide, titanium oxide, or the like on the transparent protective layer, or by thinly coating a fluorine-based substance on the transparent protective layer.

The polarized light emitting plate of the present invention may further include a support layer as required. The support layer system may be further provided with transparent supports such as glass, crystal, spinel, sapphire, etc., for example. Since such a support body is attached to the polarizing light-emitting plate, it is preferable to have a flat portion, and from the viewpoint of optical use, a transparent substrate is preferable. Transparent substrates are divided into inorganic substrates and organic substrates. For example, inorganic substrates include soda glass, borosilicate glass, crystal substrates, sapphire substrates, spinel substrates, etc., and organic substrates include acrylic, polycarbonate, Substrates composed of polyethylene terephthalate, polyethylene naphthalate, cyclic olefin polymer, etc. Transparent substrate The thickness and size are not particularly limited, and can be determined appropriately. In addition, in order to further improve the transmittance of the monomer of the polarized light-emitting panel with such a transparent substrate, it is preferable to provide an anti-reflection layer on one or both of the support surface or the polarized light-emitting panel surface. In order to bond the polarizing light-emitting plate to the flat part of the support, it is only necessary to apply a transparent adhesive (adhesive) to the flat part of the support, and then stick the polarizing light-emitting plate of the present invention on the coated surface. The adhesive or adhesive used is not particularly limited, and a commercially available one can be used, and an acrylic adhesive or adhesive is preferred.

The polarized light emitting plate of the present invention can also be used as an element emitting circularly polarized light or a circularly polarized light emitting plate, or an element emitting elliptically polarized light or an elliptical polarized light emitting plate by attaching a phase difference plate. When the polarizing light-emitting plate is further provided with a support body, etc., the supporting system may be provided on the side of the phase difference plate, or may be provided on the side of the polarizing light-emitting plate. In this way, various functional layers, supports, etc. can be further provided on the polarized light-emitting panel. Such a polarized light-emitting panel can be used in, for example, liquid crystal projectors, electronic computers, clocks, notebook computers, word processors, and liquid crystals. TV, car navigation and indoor/outdoor measuring devices or displays, lenses, glasses and other products.

The polarized light-emitting element and polarized light-emitting plate of the present invention show high absorption anisotropy in the absorption wavelength region of light (for example, the ultraviolet region to the near-ultraviolet visible light region), that is, a high degree of polarization, and furthermore, it is in the visible light region It shows polarized light emission and high transmittance. In addition, the polarized light-emitting element and polarized light-emitting plate of the present invention show excellent durability against heat, humidity, light, etc., and therefore can maintain their performance even in severe environments, and have better performance than conventional iodine-based polarizers. Higher durability. Therefore, the polarized light-emitting element and polarized light-emitting panel of the present invention can be applied to lenses or liquid crystal displays that require high transparency in the visible light region and high durability in harsh environments, such as televisions and wearable terminals. , Desktop terminals, smart phones, car screens, electronic signs used outdoors or indoors, smart windows and other display devices.

[Display device]

The display device of the present invention includes the polarized light emitting element or polarized light emitting plate of the present invention. therefore, Such a display device can form a display capable of displaying images while emitting light by irradiating light of a specific wavelength. For example, it is possible to absorb only specific wavelengths, that is, to emit polarized light of different color wavelengths on the surface of a substrate with a specific color. Furthermore, by irradiating light below 430nm (for example, ultraviolet light below 400nm), polarized light emission can also be displayed in the visible light region, and images can be displayed on the display by using this effect. By combining the above-mentioned polarized light-emitting element or polarized light-emitting plate with a liquid crystal display in this way, it can be used as a self-luminous liquid crystal display, unlike a conventional liquid crystal display equipped with a general polarizing plate. Furthermore, in the display device, when a 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 preferably provided at least on the observer side. By arranging the visible light-absorbing dye-containing layer on the side of the observer, the high-contrast visual sensitivity of the observer can be improved.

The display device of the present invention has a high transmittance in the visible light region, so there is no reduction in the transmittance of the visible light region like the conventional polarizer, or even if the transmittance is reduced, the transmittance is lower than The transmittance of the conventional polarizer is also significantly lower. For example, for conventional iodine-based polarizers and dye-based polarizers using other dye compounds, in order to set the degree of polarization to approximately 100%, the visual sensitivity in the visible light region must be corrected to 35 to 45. %about. The reason is that although the conventional polarizer has both the vertical axis and the horizontal axis as the absorption axis of light, in order to obtain a polarization degree of about 100%, it absorbs the incident light on either the vertical axis or the horizontal axis, that is, , One axis absorbs light, and the other axis produces polarized light by allowing light to pass through. In this case, since the light system of the one axis is absorbed but not penetrated, the transmittance will inevitably become less than 50%. In addition, the conventional polarizing plate is made by aligning the dichroic dye in the stretched film, but the dichroic dye is not limited to 100% orientation, and even the light transmission axis will have A little light-absorbing effect. Therefore, if the transmittance is not less than about 43% due to the surface reflection of the substance, 100% polarization cannot be achieved. In other words, if the transmittance is not reduced, high polarization cannot be achieved. In contrast, the polarized light-emitting element of the present invention or polarized The light-emitting panel has an anisotropic absorption effect in the ultraviolet region to the near-ultraviolet visible light region (for example, light from 300 to 430 nm). At this time, the polarized light-emitting element or the polarized light-emitting plate displays the polarized light emission effect of emitting polarized light in the visible light region. On the other hand, it hardly absorbs light in the visible light region, so the transmittance in the visible light region becomes very high. high. Furthermore, because the polarized light emitting effect is displayed in the visible light region, if the polarized light emitting element of the present invention is used, the transmittance is reduced very little compared to the conventional polarizing plate used to obtain the visible light of polarized light. .

Therefore, a display device using the polarized light emitting element or polarized light emitting plate of the present invention, such as a liquid crystal display, can obtain higher transparency and brightness than a liquid crystal display equipped with a conventional polarizing plate. Furthermore, since the display device equipped with the polarized light emitting element or the polarized light emitting plate of the present invention has high transparency, it is possible to obtain a display that is almost transparent although it is a liquid crystal display. In addition, because it can be designed so that polarized light will penetrate when displaying characters and images, it is possible to obtain a transparent liquid crystal display, but a display that can still be displayed, that is, it is possible to obtain a transparent display that can display characters, etc. The display. Therefore, the display device of the present invention is effective as a transparent liquid crystal display without light loss, especially a see-through display.

On the other hand, the display device of the present invention is capable of polarizing light emission by light from the ultraviolet region to the near ultraviolet visible light region, which is invisible or significantly less visible to human eyes, and can therefore be applied to Displayed liquid crystal display. By using a computer or the like to recognize the image displayed in the ultraviolet light region, it is possible to manufacture a simple and safe liquid crystal display that can be seen only when irradiated with ultraviolet light.

The display device of the present invention is, for example, a liquid crystal display capable of displaying polarized light emission by irradiating ultraviolet light, and using the polarized light to emit light. Therefore, instead of a normal liquid crystal display type display using visible light, a liquid crystal display type display using ultraviolet light can also be realized. In other words, it is possible to produce a self-luminous liquid crystal display, even in the absence of visible light or visible light In a dark space with little light, if it is a space irradiated by ultraviolet light, it can display the text, image, etc. to be displayed.

Furthermore, since the absorption band regions of the light in the visible light region and the ultraviolet region are different, it is also possible to manufacture a liquid crystal display part that displays the light in the visible light region together in the visible light region, and polarized light by ultraviolet light. It is a lens or display that can perform two different types of displays on the liquid crystal display part of the light displayed by luminescence. In particular, although there are currently displays that can perform two different displays, there is no display that displays different displays in the ultraviolet region and the visible light region by separate light sources. In this case, the lens or display device of the present invention can produce a novel display by using the above-mentioned polarized light-emitting element or polarized light-emitting plate.

The display device of the present invention can be a liquid crystal display for vehicle or outdoor display. In the car or outdoor display liquid crystal display, the liquid crystal cell used is not limited to, for example, TN liquid crystal, STN liquid crystal, VA liquid crystal, IPS liquid crystal, etc. The liquid crystal display can be used in all liquid crystal display modes. The polarized light-emitting element or polarized light-emitting plate of the present invention has excellent polarization performance with light absorption anisotropy, and shows high visible light polarization luminescence, and it can also inhibit discoloration under high temperature and high humidity in the car and outdoor. The reduced polarization performance can help improve the long-term reliability of liquid crystal displays for cars or outdoor displays.

[Example]

The following examples are used to illustrate the present invention in more detail, but these examples are illustrative and not intended to limit the present inventors. If the "%" and "parts" described below are not specifically mentioned, they are the quality standards. In addition, in each structural formula of the compound used in each example and comparative example, acidic functional groups such as sulfo groups are described in the form of free acids.

[assessment method]

The polarized light-emitting elements or polarized light-emitting plates obtained in the following examples and comparative examples are used as In order to measure the sample, the evaluation was performed as described below.

(h-1) Measurement of transmittance and absorbance of polarized light-emitting element or polarized light-emitting plate

A spectrophotometer ("U-4100" manufactured by Hitachi High Technologies) was used to evaluate the transmittance and absorbance of the polarized light-emitting element. The polarized light-emitting elements (measurement samples) produced in the various examples and comparative examples are set in the wavelength region of 220 to 2600 nm and can be irradiated with 100% polarized light (hereinafter also referred to as "absolute polarized light"). Glan-Thomoson polarizer, and measure the transmittance of light of each wavelength when irradiated with absolute polarized light for each measurement sample. In the measurement, in order to eliminate the influence of the interface reflection and evaluate the transmittance of the polarized light-emitting element, the transmittance of the substrate without the polarized light-emitting pigment is set as 100% transmittance by a spectrophotometer (generally Called the baseline). Specifically, the measurement sample contains a polarizing light-emitting dye in a polyvinyl alcohol film to produce a polarizing light-emitting element in the following examples or comparative examples, and processed into a state where the polarizing light-emitting dye is not contained in the polyvinyl alcohol film The produced film is set on the optical path of the spectrophotometer, and the measured value is set to 100% transmittance or 0% absorbance (reference line), and the transmittance or absorbance of each measurement sample is measured.

Relative to the direction of the absorption axis (the axis showing the highest light absorption) of the polarized light-emitting element, the absolute polarized light is irradiated in a way that the vibration direction of the light is orthogonal, and the measured transmittance of the light of each wavelength [That is, in the wavelength where the polarized light is the highest, when the absolutely polarized light is incident, the light transmittance on the transmission axis (the axis with the least light absorption)] is set to Ky, and the polarized light is the highest Among the wavelengths, when polarized light is incident, the absorbance of the light on the axis with the least light absorption is set to "Abs-Ky". Relative to the direction of the absorption axis of the polarized light-emitting element (the axis showing the highest light absorption), the transmittance of light of each wavelength measured by irradiating the light with the vibration direction of the light parallel to the absolute polarized light [that is, in Among the wavelengths where the polarized light is the highest wavelength, when absolutely polarized light is incident, the light transmittance on the absorption axis (the axis with the most light absorption)] is set to Kz, and the polarized light will be the highest wavelength in the polarized light. When the light is incident, the absorbance of the light on the axis where the light absorbs the most is set to "Abs- Kz". Here, the term “absolutely polarized light” refers to the polarized light that passes through the polarizer when light from the standard light is irradiated on a polarizer with a degree of polarization of approximately 100%, which means approximately 100% polarized light.

(h-2) Visual sensitivity correction monomer penetration rate Ys

The visual sensitivity correction monomer transmittance Ys of each measurement sample is in the wavelength region of 380 to 780 nm in the visible light region, and the above Ky and Kz calculated at a predetermined wavelength interval dλ (here, 5 nm) are substituted into the following Formula (I) is used to calculate the transmittance Ts of the monomer at each wavelength, and the transmittance obtained by correcting the Ts for visual sensitivity in accordance with JIS Z 8722:2009. Specifically, Ys is calculated by substituting the monomer transmittance Ts into the following formula (H). In addition, in the following formula (II), Pλ represents the spectral distribution of standard light (C light source), and τλ represents a two-dimensional field of view color matching function.

Ts=(Ky+Kz)/2‧‧‧(I)

(h-3) Polarization ρ

The above-mentioned Ky and Kz are substituted into the following formula (III) to obtain the degree of polarization ρ of each wavelength of each measurement sample.

ρ =(Ky-Kz)/(Ky+Kz)‧‧‧Formula (III)

(Production of polarizing plate for ultraviolet region)

A polyvinyl alcohol film (VF-PS # 7500 manufactured by KURARAY) having a thickness of 75 μm was immersed in warm water at 40° C. for 3 minutes to swell the film. The film obtained above is immersed in a C.I.Direct Yellow 28 0.3 part, Glauber's salt 1.0 part, 1500 parts of water in 45°C aqueous solution for 4 minutes, so that the aforementioned pigment is contained in the aforementioned film. The resulting film was immersed in a 3% boric acid aqueous solution at 50°C for 5 minutes while being stretched 5 times. The stretched film was maintained in a tight state, washed in water at room temperature for 20 seconds, and dried at 70°C for 9 minutes to obtain a polarizing element for the ultraviolet region. On the other hand, the two sides of a triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) that does not contain ultraviolet absorbers are treated with 1.5 equivalents of sodium hydroxide aqueous solution at 35°C for 10 minutes, and then washed with water at 70°C. After drying for 10 minutes at ℃, the polarizing element for the ultraviolet region is laminated on both sides of the produced polarizer with 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, Japan) to obtain visual sensitivity correction monomer wear. The polarizing plate is used in the ultraviolet region with a transmittance of 99.872%.

The Ky, Kz, monomer transmittance Ts, polarization degree ρ, "Abs-Ky", "Abs-Kz", and "Abs- The ratio of "Ky" to "Abs-Kz" ("Abs-Ky"/"Abs-Kz") is shown in Table 1, and the obtained ultraviolet region is shown in Figure 1 with Ky and Kz of each wavelength of the polarizing plate. middle. From Table 1 and Fig. 1, it can be seen that the obtained polarizing plate for the ultraviolet region has high polarization characteristics in the range of 360 to 450 nm.

[Table 1]

(h-4) Measurement of contrast of polarized light luminescence

Use 375nm LED light source (made by THORLABS, LED with mounting base M375L4°) is used as the light source, and the ultraviolet penetration and visible light blocking filter ("IUV-340" manufactured by Gosu Seiko Glass Co., Ltd.) is installed at the light source to make it a light source that can only irradiate ultraviolet rays. In the optical path, the above-obtained polarizing plate for ultraviolet rays is installed, and the 375nm light obtained from the light source is converted into polarized light. Furthermore, on the optical path, the polarizing light-emitting plates obtained in the following Examples and Comparative Examples were set, and each polarizing light-emitting plate was measured using a spectroradiometer ("USR-40" manufactured by USHIO Electric Co., Ltd.). The amount of luminescence. That is, it is configured such that the light from the light source passes through the ultraviolet penetrating and visible light blocking filter, the ultraviolet polarizing plate, and the polarizing light emitting plate in order, and the polarized light obtained from each embodiment and comparative example enters the beam splitter To measure the luminous brightness by means of a radiometer. At this time, the luminous brightness of the axis of the polarized light-emitting plate with the strongest luminescence is set to Ls, and the luminous brightness of the axis of the polarized light-emitting plate with the weakest luminescence is set to Lw.

<Synthesis of Polarized Luminescent Pigments>

(Synthesis example 1)

41.4 parts of commercially available sodium 4,4'-diaminostilbene-2,2'-disulfonate was added to 300 parts of water and stirred, and 35% hydrochloric acid was added to adjust the pH to 0.5. Add 10.9 parts of 40% sodium nitrite aqueous solution to the obtained solution, stir at 10°C for 1 hour, then add 34.4 parts of 6-aminonaphthalene-2-sulfonic acid, add 15% sodium carbonate aqueous solution and adjust to pH 4 .0, stirring for 4 hours. 60 parts of sodium chloride was added to the obtained reaction liquid, the precipitated solid was separated by filtration, and then washed with 100 parts of acetone, and the obtained wet cake was dried to obtain the compound of formula (7) as an intermediate 83.8 copies.

83.8 parts of the obtained compound of formula (7) was added to 300 parts of water and stirred, and a 25% aqueous sodium hydroxide solution was added to adjust the pH to 10.0. In the resulting solution, add 28% 20 parts of ammonia water and 9.0 parts of copper sulfate pentahydrate were stirred at 90°C for 2 hours. 25 parts of sodium chloride was added to the obtained reaction liquid, the precipitated solid was separated by filtration, and then washed with 100 parts of acetone to obtain 40.0 parts of a wet cake of the compound of formula (8). 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 (8).

(Synthesis example 2)

In a mixed solution of 45 parts of 98% sulfuric acid and 10 parts of 30% fuming sulfuric acid, 3.5 parts of 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, which is a commercially available product, is added, Stir at 25°C for 24 hours. 300 parts of water was added to the obtained reaction liquid, the precipitated solid was separated by filtration, and then washed with 100 parts of acetone to obtain 10.0 parts of wet cake. By drying the wet cake with a hot air dryer at 80°C, 2.9 parts of the water-soluble coumarin-based dichroic dye of the present invention represented by the following formula (9) was synthesized.

[Example 1]

(Production of Polarized Light-Emitting Elements)

A polyvinyl alcohol film with a thickness of 60 μm (polymerization degree 2400) was immersed in warm water at 35° C. for 3 minutes to swell the film. The film obtained above was immersed in a 20% aqueous solution of 4,4'-bis-(sulfostyryl)biphenyl disodium described in Compound Example 5-1 (Tinopal NFW Liquid manufactured by BASF) 0.03 part, Glauber's salt 1.0 part, 1000 parts of water in 45℃ aqueous solution for 10 minutes, make The resulting film was immersed in a 3% boric acid aqueous solution at 55°C for 5 minutes and extended to 6.0 times. The stretched film was maintained in a tight state, washed in water at room temperature for 2 seconds, and dried to obtain a polarized light emitting device. The thickness of the obtained polarized light emitting element was 17 μm.

(Production of polarized light-emitting board)

Treat both sides of a triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.) that does not contain ultraviolet absorbers with 1.5 equivalents of sodium hydroxide aqueous solution at 35°C for 10 minutes, wash with water, and then at 70°C Let dry for 10 minutes. On both sides of the polarized light-emitting element produced above, a triacetyl cellulose film treated with sodium hydroxide was laminated through an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, Japan) to obtain Polarized light emitting board. The obtained polarized light-emitting panel showed approximately the same optical characteristics as the polarized light-emitting element.

[Examples 2 to 6]

Except that the time (10 minutes) for immersing the swollen polyvinyl alcohol-based film of Example 1 in the 45°C aqueous solution containing the compound described in Compound Example 5-1 was changed to 8 minutes, 6 minutes, 4 minutes, Except for 2 minutes and 1 minute, the rest was the same as in Example 1, and polarized light-emitting elements and polarized light-emitting plates with different values of Ky and Kz were produced.

[Examples 7 to 9]

Except that the amount of the aqueous solution of the compound described in compound example 5-1 used in Example 1 was changed to 0.01 parts by weight relative to 1000 parts of water, and the immersion time of the swelled polyvinyl alcohol-based film (10 minutes) Except changing to 3 minutes, 2 minutes, and 1 minute, respectively, and immersing, in the same manner as in Example 1, polarized light-emitting elements and polarized light-emitting plates with different values of Ky and Kz were produced.

[Examples 10 and 11]

In addition to using 0.03 parts of the compound represented by formula (8) obtained in Synthesis Example 1 to replace the aqueous solution of the compound described in Example 5-1 used in Example 1, and the swollen polyethylene Except that the immersion time (10 minutes) of the enol-based film was changed to 4 minutes and 1 minute, respectively, in the same manner as in Example 1, polarized light-emitting elements and polarized light-emitting plates with different values of Ky and Kz were produced.

[Example 12]

In addition to using 0.03 parts of the compound represented by formula (9) obtained in Synthesis Example 2 instead of the aqueous solution of the compound described in Example 5-1 used in Example 1, and immersing the swollen polyvinyl alcohol-based film Except that the time (10 minutes) was changed to 1 minute, the rest was the same as in Example 1, and polarized light-emitting elements and polarized light-emitting plates with different values of Ky and Kz were produced.

[Comparative Example 1]

A polyvinyl alcohol film with a thickness of 60 μm (polymerization degree 2400) was immersed in warm water at 35° C. for 3 minutes to swell the film. The film obtained above was immersed in a 20% aqueous solution of 4,4'-bis-(sulfostyryl)biphenyl disodium described in Compound Example 5-1 (Tinopal NFW Liquid manufactured by BASF Corporation) 0.05 parts, Glauber's salt 1.0 part, 1000 parts of water in 45°C aqueous solution for 10 minutes. The resulting film was immersed in a 3% boric acid aqueous solution at 55°C for 5 minutes and extended to 6.0 times. The stretched film was maintained in a tight state, washed in water at room temperature for 2 seconds, and dried to obtain a polarized light emitting element with a thickness of 17 μm. In the same manner as in Example 1, a 1.5 equivalent sodium hydroxide aqueous solution was treated at 35°C for 10 minutes, and the triacetyl cellulose film (ZRD-60 manufactured by Fuji Film Co., Ltd.), which did not contain ultraviolet absorber, was washed with water. After drying at 70° C. for 10 minutes, the polarizing light-emitting plate was obtained by laminating an aqueous solution containing 4% polyvinyl alcohol resin (NH-26 manufactured by VAM & POVAL, Japan) on both sides of the produced polarizing light-emitting element.

[Comparative Example 2]

Except that the aqueous solution of the compound described in Compound Example 5-1 used in Comparative Example 1 was changed to 0.03 part of the compound represented by formula (8) prepared in Synthesis Example 1, the rest was made in the same manner as Comparative Example 2 The measurement sample.

[Comparative Example 3]

Except that the aqueous solution of the compound described in Compound Example 5-1 used in Comparative Example 1 was changed to 0.03 part of the compound represented by formula (9) prepared in Synthesis Example 2, the rest was made in the same manner as Comparative Example 3 The measurement sample.

The polarization degree obtained by correcting the monomer transmittance (Ys), Ky, and Kz of the polarizing light-emitting panels obtained in Examples 1 to 12 and Comparative Examples 1 to 3 to obtain the highest degree of polarization, that is , The wavelength with the highest absorption anisotropy (λmax), and the Ky, Kz, monomer transmittance (Ts(%)), polarization (p), "Abs-Ky", "Abs-Kz ", the ratio of "Abs-Kz" to "Abs-Ky" ("Abs-Kz"/"Abs-Ky"), and the ordered parameters (OP value) are shown in Table 2.

[Table 2]

According to the results in Table 2, the polarized light-emitting panel of the present invention shows a high transmittance of over 98% for visual sensitivity correction, and "Abs-Ky" is 0.00039 to 0.11064, "Abs-Kz"/"Abs -Ky" is 10 or more. In other words, it can be seen that polarized light-emitting elements and polarized light-emitting panels can be obtained, which exhibit absorption anisotropy in the wavelength region of the absorbed light (that is, exhibit polarization effect), and the polarized light is incident at the wavelength where the aforementioned polarization effect is the highest. When light, "Abs-Ky" is 0.0001 to 0.12. On the other hand, it can be seen that the "Abs-Ky" of Comparative Examples 1 to 3 is 0.13966 to 0.14297, and a polarized light-emitting element and a polarized light-emitting plate outside the scope of the present invention are obtained.

Next, compare the absorbance in Ky (Abs-Ky), the absorbance in Kz (Abs-Kz), and The wavelength at which the luminous intensity is the highest (λmax-E), the Lw, Ls of this wavelength, and the contrast ratio (Emission CR) which is the ratio of Ls to Lw are shown in Table 3. Also, for reference, the relationship between "Abs-Ky" and Emission CR in Examples 1 to 4, Example 10, and Comparative Examples 1 to 3 where "Abs-Kz" is shown as 1.0 to 3.5 is shown in FIG. 2 , And the relationship between "Abs-Kz" and Emission CR is shown in Figure 3.

[table 3]

According to Table 3, it can be seen that the "Abs-Ky" of the polarized light-emitting plate of the present invention is 0.00039 to 0.11064. When polarized light is incident with polarized light in the highest wavelength, "Abs-Ky" is 0.0001 to 0.12; the polarized light-emitting element and the polarized light-emitting plate are not But the visual sensitivity correction monomer transmittance (Ys) is more than 98%, and the luminous brightness between the axis showing strong luminous brightness and the axis showing weak luminous brightness shows a contrast of 5 or more (Emission CR), and it can be seen that A polarized light-emitting panel with high visibility can be obtained. Also, according to Figure 2, it is shown that the contrast (Emission CR) of its luminous brightness is "Abs-Ky", that is, when polarized light is incident, it has a strong correlation with "Abs-Ky", and its absorbance The lower the value, the higher its "Emission CR". On the other hand, according to Figure 3, it is shown that even if the "Emission CR" is high when the polarized light is incident, the contrast of the luminous brightness may not be high, and the "Abs-Ky" and "Emission" CR" does not necessarily show relevance. This situation is different from Patent Document 7. As in Patent Document 7, the order parameter of the polarized luminescent pigment on the axis of light emission is set to 0.81 to 0.95 to improve the brightness and visually recognize the polarized light through the polarizer. The situation of the contrast of the light is different from the situation of viewing the contrast of the brightness of the light emitted on each axis as in the invention of this case, and the suitable design is different. The polarized light-emitting panel obtained in the present invention has high transmittance and can provide high contrast. This situation shows that lenses and display devices equipped with the polarized light-emitting element or polarized light-emitting plate of the present invention (for example, liquid crystal display devices equipped with the polarized light-emitting element or polarized light-emitting plate of the invention, etc.) can have high transmittance (transparency) ) At the same time, it has a high luminous contrast.

[Industrial availability]

In this way, the polarized light-emitting element and polarized light-emitting plate of the present invention can improve the contrast of each axis of the self-luminous polarizing film (that is, the polarized light-emitting film), and has excellent durability, and at the same time, it has high performance in the visible light region. Penetration rate. The contrast value of general book text is in the range of 5-10. The polarized light emitting element and the polarized light emitting plate of the present invention can provide polarized light emission having a contrast equivalent to this range or having a contrast greater than this range. Therefore, the optical components and display devices equipped with the polarized light emitting element and the lens of the polarized light emitting plate of the present invention have high transparency in the visible light region and can display images with polarized light for a long time, so they can be applied to televisions and personal applications. Computers, wearable terminals, lenses, and transparent displays (see-through displays) are widely used. In addition, because it can emit light by ultraviolet light, the polarized light-emitting element and polarized light-emitting plate of the present invention can also be applied to requirements such as seeking to display functions by irradiation of invisible light such as ultraviolet light that is difficult to recognize by human eyes. Functional media such as high-security displays and sensors.

Claims (11)

A polarized light-emitting element is provided with a substrate; wherein, The aforementioned substrate contains at least one polarized light emitting pigment, The aforementioned polarized light emitting pigment is oriented on the aforementioned substrate, The aforementioned polarized light emitting element exhibits a polarizing effect in the wavelength region of the absorbed light, Moreover, when the polarized light with the highest wavelength of the aforementioned polarization is incident, the absorbance (Abs-Ky) of the axis with the least absorption is 0.0001 to 0.12. The polarized light-emitting element according to claim 1, wherein when the polarized light with the highest wavelength of the polarization action is incident, the absorbance of the axis with the largest absorption (Abs-Kz) versus the absorbance of the axis with the least absorption (Abs -Ky) ratio ("Abs-Kz"/"Abs-Ky") is 10 to 200. The polarized light-emitting element according to claim 1 or 2, wherein the polarized light-emitting dye has fluorescent light-emitting characteristics. The polarized light-emitting element according to any one of claims 1 to 3, wherein the polarized light-emitting dye has a light-emitting characteristic capable of polarizing light in the visible light region by absorbing light in the ultraviolet region to the near-ultraviolet visible light region. The polarized light-emitting element according to any one of claims 1 to 4, wherein the polarized light-emitting dye is selected from the group consisting of a biphenyl skeleton, a stilbene skeleton, and a coumarin skeleton in its chemical structural formula Any type of skeleton in the group. The polarized light-emitting element according to any one of claims 1 to 5, wherein the polarized light-emitting dye is a compound represented by the following formula (1) or a salt thereof:

In the formula, L and M are each independently selected from a nitro group, an amino group which may have a substituent, a carbonylamino group which may have a substituent, a naphthotriazole group which may have a substituent, and a C which may have a substituent. _The group consisting of 1-20 alkyl groups, vinyl groups that may have substituents, amide groups that may have substituents, ureido groups that may have substituents, aryl groups that may have substituents, and carbonyl groups that may have substituents Group. The polarized light emitting element according to any one of claims 1 to 6, wherein the base material contains polyvinyl alcohol. The polarized light-emitting element according to any one of claims 1 to 7, wherein the substrate includes an oriented polyvinyl alcohol film. The polarized light emitting device according to any one of claims 1 to 8, wherein the substrate further contains a boron compound. A polarized light-emitting panel is provided with the polarized light-emitting element according to any one of claims 1 to 9 and a transparent protective layer on one or both sides of the polarized light-emitting element. A display device is provided with the polarized light-emitting element according to any one of claims 1 to 9 or the polarized light-emitting panel according to claim 10.

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