JP2026005609A - Color-converting composition, color-converting member, and light source unit, display, and lighting device including the same - Google Patents

Abstract

[Problem] To achieve both improved color reproducibility and improved durability in color-converting compositions and color-converting members used in light source units, displays, and lighting devices, and in particular to achieve both high color purity light emission and high durability.
The color-changing composition contains at least one organic light-emitting material and a binder resin, and satisfies the following formula (A-1):

(In formula (A-1), E _F represents energy at a peak wavelength of a fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents energy at a peak wavelength of a phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution.)
[Selected Figure] Figure 1

Description

The present invention relates to a color-converting composition, a color-converting member, and a light source unit, display, and lighting device that include the same.

There is active research into applying multi-color technology using color conversion methods to LCD displays, organic EL displays, lighting devices, and more. Color conversion refers to converting the light emitted from an illuminant into light with a longer wavelength; for example, converting blue light into green or red light.

By forming this composition with color conversion functionality (hereinafter referred to as the color conversion composition) into a sheet and combining it with, for example, a blue light source, it is possible to obtain the three primary colors of blue, green, and red from the blue light source, i.e., to obtain white light. By combining such a blue light source with a sheet with color conversion functionality (hereinafter referred to as the color conversion sheet) as a light source unit such as a backlight unit, and combining this light source unit with a liquid crystal driver and a color filter, it is possible to create a full-color display. Furthermore, a white light source combining a blue light source with a color conversion sheet can also be used directly as a white light source (lighting device) such as an LED light source.

Improved color reproducibility and durability are challenges facing displays that use color conversion technology. Narrowing the half-width of the blue, green, and red emission spectra of the light source unit and increasing the color purity of each color are effective ways to improve color reproducibility. To address this issue, for example, a technique using quantum dots as a component of a color conversion composition has been proposed (see, for example, Patent Document 1). Color conversion materials containing organic light-emitting materials have also been proposed (see, for example, Patent Documents 2 and 3). Examples of techniques proposed for preventing degradation of organic light-emitting materials and improving durability include the addition of a light stabilizer (see, for example, Patent Document 4) and the use of an oxygen barrier to improve durability (see, for example, Patent Document 5).

JP 2012-22028 A JP 2010-61824 A Japanese Patent Application Laid-Open No. 2014-136771 JP 2019-50381 A International Publication No. 2017/057287

The technology using quantum dots described in Patent Document 1 does indeed narrow the half-width of the green and red emission spectra, improving color reproducibility. However, quantum dots are vulnerable to heat, moisture in the air, and oxygen, and are not sufficiently durable. There are also issues with the technology, such as the fact that it contains cadmium.

Furthermore, in recent years, with the trend toward higher resolutions such as 4K and 8K, high dynamic range (HDR), and higher contrast achieved through local dimming, the illuminance required of display light source units has increased. This has resulted in higher temperatures in light source units due to drive heat. However, while the technologies using organic light-emitting materials described in Patent Documents 2 and 3 can certainly improve color reproducibility, they lack durability at high temperatures. Furthermore, existing technologies such as the light stabilizer described in Patent Document 4 and the oxygen barrier described in Patent Document 5 are effective in improving durability, but are insufficient for improving durability at high temperatures. In particular, color conversion materials using organic light-emitting materials have the issue of significantly reduced durability at high temperatures, and the above existing technologies have not yet fully resolved this issue.

The problem that the present invention aims to solve is to achieve both improved color reproducibility and durability in a color conversion composition or color conversion member (e.g., color conversion sheet) used in a light source unit, display, or lighting device. In other words, the present invention aims to provide a color conversion composition and color conversion member that achieve both high color purity and high durability, and that have improved durability, particularly at high temperatures.

To solve the above-mentioned problems and achieve the above-mentioned objectives, the present invention has one of the following configurations.

That is, the color-changing composition of the present invention is a color-changing composition that contains [1] at least one organic light-emitting material and a binder resin, and is characterized by satisfying the following formula (A-1):

(In formula (A-1), E _F represents energy at a peak wavelength of a fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents energy at a peak wavelength of a phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution.)

Furthermore, the color-changing composition according to the present invention is [2] the invention described in [1] above, characterized in that it satisfies the following formula (A-2):

(In formula (A-2), E _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in a dilute toluene solution in a temperature range of −50° C. or more and 50° C. or less. _{E RISC} is a value that can be calculated using the following formula (A-3).)

(In formula (A-3), ln represents the natural logarithm. _{k RISC} represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at each temperature. T represents the temperature [K] of the dilute toluene solution. _kB represents Boltzmann's constant. E _RISC in formula (A-2) can be determined by first determining the reverse intersystem crossing rate constant k _RISC at each temperature T, and then using formula (A-3), plotting the values of lnk _RISC T ^0.5 at each temperature T with lnk _RISC T ^0.5 as the vertical axis and 1/T as the horizontal axis, and referring to the slope of an approximation line based on the plotted values of lnk _RISC T ^0.5 . lnA can be determined from the intersection of the approximation line and the vertical axis at 1/T=0.)

Furthermore, the color-changing composition according to the present invention is characterized in that, in the invention described in [1] or [2] above, it satisfies the following formula (A-4):

(In formula (A-4), k _RISC (30° C.) represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at 30° C.)

Furthermore, the color-changing composition according to the present invention is [4] the invention described in any one of [1] to [3] above, characterized in that it satisfies the following formula (A-5):

(In formula (A-5), Δy is the absolute value of the amount of change in chromaticity y from the initial value in the xy coordinates of the color-converted transmitted light when continuous light irradiation is performed for 200 hours using light from a blue LED having a peak wavelength in the range of 450 nm±3 nm and an intensity of 8000 nits. Δy(75°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 75°C. Δy(30°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 30°C.)

Furthermore, the color-converting composition of the present invention is characterized in that, in the invention described in any one of [1] to [4] above, the peak wavelength of the fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution is in a wavelength range of 500 nm or more.

Furthermore, the color conversion member according to the present invention is [6] a color conversion member according to any one of the above [1] to [5], which contains at least one organic light-emitting material and a binder resin, and is characterized in that it satisfies the following formula (A-1):

(In formula (A-1), E _F represents energy at a peak wavelength of a fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents energy at a peak wavelength of a phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution.)

Furthermore, the color conversion member according to the present invention is characterized in that, in the invention described in [7] above [6], the following formula (A-6) is satisfied:

(In formula (A-6), _E'F represents the energy at the peak wavelength of the fluorescent emission spectrum of the color conversion member. _E'P represents the energy at the peak wavelength of the phosphorescent emission spectrum of the color conversion member.)

Furthermore, the color conversion member according to the present invention is characterized in that, in the invention described in [8] or [7] above, it satisfies the following formula (A-7):

(In formula (A-7), E' _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in the color conversion member in a temperature range of -50°C or more and 50°C or less. E' _RISC is a value that can be calculated using the following formula (A-8).)

(In formula (A-8), ln represents the natural logarithm. k' _RISC represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in the color conversion member at each temperature. T' represents the temperature [K] of the color conversion member. _kB represents the Boltzmann constant. E' _RISC in formula (A-7) can be determined by first determining the reverse intersystem crossing rate constant k' _RISC at each temperature T', and then using formula (A-8), plotting the values of lnk' _RISC T' ^0.5 at each temperature T' with lnk' _RISC T' ^0.5 on the vertical axis and 1/T' on the horizontal axis, and referring to the slope of the approximation line based on the plotted values of lnk' _RISC T' ^0.5 . lnA' can be determined from the intersection of the approximation line and the vertical axis at 1/T' = 0.)

Furthermore, the color conversion member according to the present invention is characterized in that, in the invention described in any one of [6] to [8] above, the following formula (A-9) is satisfied:

(In formula (A-9), k' _RISC (30°C) represents the rate constant of reverse intersystem crossing of the at least one organic light-emitting material contained in the color conversion member at 30°C.)

Furthermore, the color conversion member according to the present invention is characterized in that, in the invention described in any one of [6] to [9] above, the following formula (A-5) is satisfied:

(In formula (A-5), Δy is the absolute value of the amount of change in chromaticity y from the initial value in the xy coordinates of the color-converted transmitted light when continuous light irradiation is performed for 200 hours using light from a blue LED having a peak wavelength in the range of 450 nm±3 nm and an intensity of 8000 nits. Δy(75°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 75°C. Δy(30°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 30°C.)

Furthermore, the color conversion member according to the present invention is [11] the invention described in any one of [6] to [10] above, characterized in that the peak wavelength of the fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution is in a wavelength range of 500 nm or more.

Furthermore, the color conversion member according to the present invention is characterized in that, [12] in any one of the inventions [6] to [11] above, it has an oxygen barrier layer.

The light source unit according to the present invention is characterized by comprising a light source [13] and a color conversion member described in any one of [6] to [12] above.

Furthermore, the display according to the present invention is characterized in that it includes the light source unit described in [14] above [13].

Furthermore, the lighting device according to the present invention is characterized in that it includes the light source unit described in [15] above [13].

The color-converting composition of the present invention and the color-converting member using the same are capable of emitting light with high color purity and exhibiting high durability, even at high temperatures, thereby achieving the effect of achieving both improved color reproducibility and improved durability.

FIG. 1 is a schematic cross-sectional view showing a first example of a color conversion member according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a second example of a color conversion member according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a third example of a color conversion member according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a fourth example of a color conversion member according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a fifth example of a color conversion member according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing a sixth example of a color conversion member according to an embodiment of the present invention.

Preferred embodiments of the color-converting composition and color-converting member according to the present invention, as well as light source units, displays, and lighting devices containing the same, are described in detail below. However, the present invention is not limited to the following embodiments and can be modified in various ways depending on the purpose and application. Furthermore, matters cited as preferred examples in specific embodiments and implementations can also be applied to other embodiments and implementations.

<Color-Converting Composition and Color-Converting Member>
A color-converting composition according to an embodiment of the present invention (hereinafter sometimes abbreviated as the color-converting composition of the present invention) contains at least one organic light-emitting material and a binder resin. A color-converting member according to an embodiment of the present invention (hereinafter sometimes abbreviated as the color-converting member of the present invention) contains the color-converting composition of the present invention or a cured product thereof. That is, the color-converting member of the present invention contains at least one organic light-emitting material and a binder resin, similar to the color-converting composition of the present invention.

<Light-emitting materials>
The color-converting composition and color-converting member of the present invention each contain at least one organic light-emitting material. Here, the term "light-emitting material" as used herein refers to a material that, when irradiated with a certain type of light, emits light of a wavelength different from that light. Examples of light-emitting materials include inorganic phosphors, fluorescent pigments, fluorescent dyes, quantum dots, and organic light-emitting materials. Among these, organic light-emitting materials are superior to other light-emitting materials in terms of uniformity of dispersion, reduced usage, and reduced environmental impact.

In each of the color-converting composition and color-converting member of the present invention, the organic light-emitting material contained satisfies the following formula (A-1):

In formula (A-1), E _F represents the energy at the peak wavelength of the fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents the energy at the peak wavelength of the phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. The light wavelength λ _em [nm] can be converted to energy E _hv [eV] using the formula E _hv = 1240/λ _em .

In each of the color conversion compositions and color conversion members, when the organic light-emitting material contained therein satisfies formula (A-1), the energy levels of the organic light-emitting material in the singlet excited state and the organic light-emitting material in the triplet excited state are close to each other. Therefore, thermal energy derived from the heat generated by the operation of a device such as a light source unit causes reverse intersystem crossing from the organic light-emitting material in the triplet excited state to the organic light-emitting material in the singlet excited state. Because organic light-emitting materials in the triplet excited state are highly reactive and have a long lifetime, they are prone to react with surrounding molecules. This is one of the main causes of deterioration (e.g., oxidative deterioration) of organic light-emitting materials. Therefore, the aforementioned reverse intersystem crossing is effective in improving the durability of color conversion compositions and color conversion members containing such organic light-emitting materials. In each of the color conversion compositions and color conversion members of the present invention, the organic light-emitting material contained therein satisfies formula (A-1), and therefore the aforementioned reverse intersystem crossing can occur more quickly than the organic light-emitting material deteriorates, for example, in a high-temperature environment elevated from room temperature by the aforementioned thermal energy.

It is preferable that the reverse intersystem crossing occurs earlier than the deterioration of the organic light-emitting material. That is, in formula (A-1), the smaller the value of E _F - E _P , the more preferable. Specifically, the value of E _F - E _P is more preferably 0.020 eV or less, even more preferably 0.015 eV or less, and particularly preferably 0.010 eV or less. The value of _{E F} - E _P may be a negative value. In this case, the aforementioned reverse intersystem crossing is energetically dominant, and reverse intersystem crossing occurs very quickly, which is preferable. The lower limit of the value of _{E F} - E _P is not particularly limited, but is preferably -0.030 eV or more.

In addition, organic light-emitting materials that satisfy formula (A-1) are preferred because they can exhibit highly efficient light emission. Typically, fluorescent light is emitted from a light-emitting material in a singlet excited state, which is generated after the light-emitting material is photoexcited. Light-emitting materials in a triplet excited state, which is generated by intersystem crossing, are thermally deactivated in a room temperature environment. Therefore, fluorescent light is not emitted from the light-emitting material in the triplet excited state. On the other hand, organic light-emitting materials that satisfy formula (A-1) quickly convert a triplet excited state into a singlet excited state and then emit fluorescent light, even if the triplet excited state is generated. Therefore, organic light-emitting materials in a triplet excited state, which cannot contribute to light emission in ordinary fluorescent light-emitting materials, can also contribute to fluorescent emission. Therefore, highly efficient light emission can be obtained from organic light-emitting materials that satisfy formula (A-1).

The color-converting composition of the present invention preferably further satisfies the following formula (A-2). In other words, it is more preferable that the organic light-emitting material contained in the color-converting composition of the present invention satisfies formula (A-2).

In formula (A-2), E _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in a dilute toluene solution in a temperature range of −50° C. to 50° C. The E _RISC is a value that can be calculated using the following formula (A-3):

In formula (A-3), ln represents the natural logarithm. _{k RISC} represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at each temperature. T represents the temperature [K] of the dilute toluene solution containing the at least one organic light-emitting material. _kB represents the Boltzmann constant. E _RISC in formula (A-2) can be determined by first determining the reverse intersystem crossing rate constant k _RISC at each temperature T, then plotting the lnk _RISC T ^0.5 values at each temperature T using formula (A-3) with lnk _RISC T ^0.5 on the vertical axis and 1/T on the horizontal axis, and referencing the slope of the approximation line based on the plotted lnk _RISC T ^0.5 values. lnA can be determined from the intersection of the approximation line and the vertical axis at 1/T = 0.

Here, equation (A-3) is derived from equations (A-10) and (A-11) below, with reference to Nature Communications volume 11,3909 (2020) and other sources.

In formulas (A-10) and (A-11), h represents Planck's constant, _HSO represents the spin-orbit interaction between the triplet excited state and the singlet excited state, and λ represents the reorganization energy.

When the color-converting composition of the present invention satisfies formula (A-2), the activation energy of reverse intersystem crossing can be exceeded by thermal energy derived from the driving heat of a device such as a light source unit in the organic light-emitting material contained in the color-converting composition, making it easier for reverse intersystem crossing to occur from an organic light-emitting material in a triplet excited state to an organic light-emitting material in a singlet excited state. Therefore, it is more preferable that the color-converting composition of the present invention satisfies formula (A-2). As described above, the triplet excited state of an organic light-emitting material is one of the main causes of deterioration of the organic light-emitting material, and therefore the aforementioned reverse intersystem crossing is effective in improving the durability of a color-converting composition containing such an organic light-emitting material. It is preferable that this reverse intersystem crossing occur more quickly than the deterioration of the organic light-emitting material. In other words, in formula (A-2), the smaller the value of E _RISC , the more preferable. Specifically, the value of E _RISC is more preferably 0.028 eV/mol or less, even more preferably 0.026 eV/mol or less, and particularly preferably 0.024 eV/mol or less. The lower limit of E _RISC is not particularly limited, but is preferably 0.000 eV or more.

The color-converting composition of the present invention preferably further satisfies the following formula (A-4). In other words, it is more preferable that the organic light-emitting material contained in the color-converting composition of the present invention satisfies formula (A-4).

In formula (A-4), k _RISC (30° C.) represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at 30° C.

When the color-converting composition of the present invention satisfies formula (A-4), reverse intersystem crossing from the triplet excited state to the singlet excited state of the organic light-emitting material contained in the color-converting composition can occur at a sufficiently high rate in the temperature range in which the color-converting composition is actually used (the actual use temperature range). This makes it possible to further suppress deterioration of the organic light-emitting material in high-temperature environments. The value of k _RISC (30°C) is more preferably 0.70×10 ⁵ s ^-1 or more, even more preferably 1.0×10 ⁵ s ^-1 or more, and particularly preferably 1.2×10 ⁵ s ^-1 or more. The larger the value of k _RISC (30°C), the better. While the upper limit is not particularly limited, it is preferably 1.0×10 ¹⁰ s ^-1 or less.

The color conversion member of the present invention preferably further satisfies the following formula (A-6). In other words, it is more preferable that the organic light-emitting material contained in the color conversion member of the present invention satisfies formula (A-6).

In formula (A-6), _E'F represents the energy at the peak wavelength of the fluorescent emission spectrum of the color conversion member, and _E'P represents the energy at the peak wavelength of the phosphorescent emission spectrum of the color conversion member.

As described above, the color conversion member of the present invention contains at least one organic light-emitting material and a binder resin. Therefore, the organic light-emitting material in the color conversion member is in a different environment from the organic light-emitting material in solution. When the color conversion member of the present invention satisfies formula (A-6) in addition to formula (A-1), the organic light-emitting material in the color conversion member can undergo reverse intersystem crossing from a triplet excited state to a singlet excited state at a rate sufficiently faster than the degradation of the organic light-emitting material. This can further suppress the degradation of the organic light-emitting material in high-temperature environments. This reverse intersystem crossing should occur more quickly than the degradation of the organic light-emitting material in the color conversion member (in the binder resin). That is, in formula (A-6), the smaller the value of E' _F -E' _P , the more preferable. Specifically, the value of E' _F -E' _P is more preferably 0.020 eV or less, even more preferably 0.015 eV or less, and particularly preferably 0.010 eV or less. The value of E' _F -E' _P may be a negative value. In this case, the reverse intersystem crossing described above is energetically dominant, and reverse intersystem crossing occurs very quickly, which is preferable. The lower limit of the value of E' _F -E' _P is not particularly limited, but is preferably -0.030 eV or more.

The color conversion member of the present invention preferably further satisfies the following formula (A-7). In other words, it is more preferable that the organic light-emitting material contained in the color conversion member of the present invention satisfies formula (A-7).

In formula (A-7), E' _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in the color conversion member in a temperature range of −50° C. to 50° C. The E' _RISC is a value that can be calculated using the following formula (A-8):

In formula (A-8), ln represents the natural logarithm. k' _RISC represents the reverse intersystem crossing rate constant of at least one organic light-emitting material contained in the color conversion member at each temperature. T' represents the temperature [K] of the color conversion member containing at least one organic light-emitting material. _kB represents the Boltzmann constant. E' _RISC in formula (A-7) can be determined by first determining the reverse intersystem crossing rate constant k' _RISC at each temperature T', then plotting the lnk' _RISC T' ^0.5 values at each temperature T' using formula (A-8) with lnk' _RISC T' ^0.5 on the vertical axis and 1/T' on the horizontal axis, and referencing the slope of the approximation line based on the plotted lnk' _RISC T' ^0.5 values. lnA' can be determined from the intersection of the approximation line and the vertical axis at 1/T' = 0. Here, the formula (A-8) is derived in the same manner as the formula (A-3) described above.

When the color conversion member of the present invention satisfies formula (A-7), the activation energy of reverse intersystem crossing can be exceeded by thermal energy derived from the driving heat of a device such as a light source unit in the organic light-emitting material contained in the color conversion member, making it easier for reverse intersystem crossing to occur from an organic light-emitting material in a triplet excited state to an organic light-emitting material in a singlet excited state. Therefore, it is more preferable for the color conversion member of the present invention to satisfy formula (A-7). As described above, the triplet excited state of an organic light-emitting material is one of the main causes of deterioration of the organic light-emitting material, and therefore the aforementioned reverse intersystem crossing is effective in improving the durability of a color conversion member containing such an organic light-emitting material. It is preferable that this reverse intersystem crossing occur more quickly than the deterioration of the organic light-emitting material. In other words, in formula (A-7), the smaller the value of E' _RISC , the more preferable. Specifically, the value of E' _RISC is more preferably 0.028 eV/mol or less, even more preferably 0.026 eV/mol or less, and particularly preferably 0.024 eV/mol or less. The lower limit of _E'RISC is not particularly limited, but is preferably 0.000 eV or more.

The color conversion member of the present invention preferably further satisfies the following formula (A-9). In other words, it is more preferable that the organic light-emitting material contained in the color conversion member of the present invention satisfies formula (A-9).

In formula (A-9), _k'RISC (30°C) represents the rate constant of reverse intersystem crossing at 30°C of the at least one organic light-emitting material contained in the color conversion member.

When the color conversion member of the present invention satisfies formula (A-9), reverse intersystem crossing from the triplet excited state to the singlet excited state of the organic light-emitting material contained in the color conversion member can occur sufficiently rapidly in the temperature range in which the color conversion member is actually used (the actual use temperature range). This makes it possible to further suppress deterioration of the organic light-emitting material in high-temperature environments. The value of k' _RISC (30°C) is more preferably 0.70 x 10 ⁵ s ^-1 or more, even more preferably 1.0 x 10 ⁵ s ^-1 or more, and particularly preferably 1.2 x 10 ⁵ s ^-1 or more. The larger the value of k' _RISC (30°C), the better. While the upper limit is not particularly limited, it is preferably 1.0 x 10 ¹⁰ s ^-1 or less.

It is preferable that each of the color-converting compositions and color-converting members of the present invention further satisfy the following formula (A-5). That is, it is more preferable that the organic light-emitting material contained in each of the color-converting compositions and color-converting members of the present invention satisfy formula (A-5).

In formula (A-5), Δy is the absolute value of the change in chromaticity y from the initial value in the xy coordinates of the color-converted transmitted light when continuously irradiated for 200 hours with light from a blue LED with a peak wavelength in the range of 450 nm ± 3 nm and an intensity of 8000 nits. Δy (75°C) represents the Δy when the above continuous light irradiation was performed while maintaining the temperature at 75°C. Δy (30°C) represents the Δy when the above continuous light irradiation was performed while maintaining the temperature at 30°C.

When the color conversion composition and color conversion member of the present invention each satisfy formula (A-5), reverse intersystem crossing from the triplet excited state to the singlet excited state of the organic light-emitting material can occur at a sufficiently high rate within the temperature range of actual use. Therefore, the color conversion composition and color conversion member of the present invention can exhibit durability equal to or greater than that under low-temperature conditions, even in high-temperature environments caused by the heat generated by driving devices such as light source units. Furthermore, when the color conversion composition or color conversion member described above is used in light source units, displays, and lighting devices, it is possible to suppress accelerated deterioration of the organic light-emitting material due to high temperatures. The value of Δy(75°C)/Δy(30°C) is more preferably 0.80 or less, and particularly preferably 0.50 or less.

<Organic light-emitting materials>
Examples of organic light-emitting materials that can be used in the color-converting composition and color-converting member of the present invention include the following: Suitable organic light-emitting materials include compounds having a fused aryl ring, such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, and indene, and derivatives thereof. Suitable organic light-emitting materials also include compounds having a heteroaryl ring, such as furan, pyrrole, thiophene, silole, 9-silafluorene, 9,9'-spirobisilafluorene, benzothiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyridine, pyrazine, naphthyridine, quinoxaline, and pyrrolopyridine, and derivatives thereof, and borane derivatives.

Suitable organic light-emitting materials include stilbene derivatives such as 1,4-distyrylbenzene, 4,4'-bis(2-(4-diphenylaminophenyl)ethenyl)biphenyl, and 4,4'-bis(N-(stilben-4-yl)-N-phenylamino)stilbene; aromatic acetylene derivatives; tetraphenylbutadiene derivatives; aldazine derivatives; pyrromethene derivatives; and diketopyrrolo[3,4-c]pyrrole derivatives. Suitable organic light-emitting materials also include coumarin derivatives such as coumarin 6, coumarin 7, and coumarin 153; azole derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, and triazole, as well as metal complexes thereof; cyanine compounds such as indocyanine green; and xanthene and thioxanthene compounds such as fluorescein, eosin, and rhodamine.

Suitable organic light-emitting materials include polyphenylene compounds, naphthalimide derivatives, phthalocyanine derivatives and their metal complexes, porphyrin derivatives and their metal complexes, oxazine compounds such as Nile Red and Nile Blue, helicene compounds, and aromatic amine derivatives such as N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine. Suitable organic light-emitting materials include organometallic complex compounds of iridium (Ir), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt), osmium (Os), europium (Eu), and rhenium (Re). However, the organic light-emitting materials of the present invention are not limited to those described above. The organic light-emitting materials of the present invention may be fluorescent or phosphorescent materials.

One embodiment of the organic light-emitting material of the present invention is an organic light-emitting material containing a compound having a partial structure represented by general formula (1).

In general formula (1), B is a boron atom, N is a nitrogen atom, and C is a carbon atom. n is an integer of 0 to 2. When n is 0, the partial structure represented by general formula (1) represents a direct bond structure between B and N.

Compounds having a partial structure represented by general formula (1) exhibit high color purity due to the interaction between the Lewis acidic boron atom and the Lewis basic nitrogen atom. Furthermore, in compounds having a partial structure represented by general formula (1), the electron-donating nitrogen atom and the electron-accepting boron atom are closely positioned within the molecule. Compounds having such a partial structure are capable of separating the HOMO (highest occupied molecular orbital) orbital and the LUMO (lowest unoccupied molecular orbital) orbital through the multiple resonance effect. In organic light-emitting materials containing such compounds, the energy levels of the singlet excited state and the triplet excited state can be brought closer together. To clearly separate the HOMO orbital and the LUMO orbital, thereby bringing the energy levels of the singlet excited state and the triplet excited state of the organic light-emitting material closer together, it is preferable that the organic light-emitting material have two or more partial structures represented by general formula (1) within the molecule.

Another embodiment of the organic light-emitting material of the present invention is an organic light-emitting material containing at least one of a compound represented by general formula (2) and a compound represented by general formula (3).

In general formula (2) or general formula (3), rings Za, Zb, and Zc are each independently a substituted or unsubstituted aryl ring having 5 to 30 ring members, or a substituted or unsubstituted heteroaryl ring having 5 to 30 ring members.

In general formula (2), ^Z1 and ^Z2 are each independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra), or a sulfur atom. When ^Z1 is NRa, the substituent Ra may be bonded to ring Za or ring Zb to form a ring. When ^Z2 is NRa, the substituent Ra may be bonded to ring Za or ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (a silicon atom having a substituent Ra), or P=O.

In general formula (3), ^E1 and ^E2 are each independently BRa (boron atom having a substituent Ra), PRa (phosphorus atom having a substituent Ra), _SiRa2 (silicon atom having two substituents Ra), P(=O) _Ra2 (phosphine oxide having two substituents Ra), P(=S) _Ra2 (phosphine sulfide having two substituents Ra), C=O (carbonyl group), S(=O), or S(=O) ₂ . When ^E1 is BRa, PRa, _SiRa2 , P(=O) _Ra2 , or P(=S) _Ra2 , the substituent Ra may be bonded to ring Za or ring Zb to form a ring. When ^E2 is BRa, PRa, _SiRa2 , P(=O) _Ra2 or P(=S) _Ra2 , the substituent Ra may be bonded to ring Za or ring Zc to form a ring.

The above-mentioned substituents Ra are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, a halogen atom, a cyano group, an aldehyde group, a carbonyl group, a carboxy group, an oxycarbonyl group, an ester group, a carbamoyl group, an amide group, a sulfonyl group, a sulfonate ester group, a sulfonamide group, an amino group, an imino group, a nitro group, a silyl group, a siloxanyl group, a boryl group, a phosphine oxide group, and a fused ring or aliphatic ring formed between an adjacent substituent. The substituent Ra may be further substituted with a substituent selected from among these. The substituent substituting the substituent Ra may also be further substituted with a substituent selected from among these.

Another embodiment of the organic light-emitting material of the present invention is an organic light-emitting material containing a compound represented by general formula (4).

In general formula (4), rings Zd, Ze, Zf, Zg, Zh, and Zi are each independently a substituted or unsubstituted aryl ring having 5 to 30 ring members, or a substituted or unsubstituted heteroaryl ring having 5 to 30 ring members.

In addition, in general formula (4), ^Z3 and ^Z4 are each independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra), or a sulfur atom. When ^Z3 is NRa, the substituent Ra may be bonded to ring Zd or ring Ze to form a ring. When ^Z4 is NRa, the substituent Ra may be bonded to ring Zh or ring Zi to form a ring. However, the substituent Ra is the same as the substituent Ra in the above general formula (2) or general formula (3).

^R is a group selected from a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, an aryl group, a heteroaryl group, a halogen atom, a cyano group, an aldehyde group, a carboxy group, an ester group, an amide group, an acyl group, a sulfonyl group, a sulfonate ester group, a sulfonamide group, a nitro group, a silyl group, a siloxanyl group, a boryl group, and a phosphine oxide group. The selected group may form a ring structure with an adjacent group.

In all of the above groups, hydrogen may be replaced with deuterium. This also applies to the compounds or partial structures described below. In the following description, for example, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms refers to an aryl group having 6 to 40 carbon atoms, including the carbon atoms contained in the substituents substituted on the aryl group. The same applies to other substituents that specify the number of carbon atoms.

When referring to "substituted or unsubstituted," "unsubstituted" means that a hydrogen atom or deuterium atom has been substituted. The same applies to "substituted or unsubstituted" in the compounds or partial structures described below.

In addition, for all of the above groups, examples of the substituent when substituted include alkyl groups, cycloalkyl groups, heterocyclic groups, alkenyl groups, cycloalkenyl groups, alkynyl groups, aryl groups, heteroaryl groups, hydroxyl groups, thiol groups, alkoxy groups, alkylthio groups, aryl ether groups, aryl thioether groups, halogen atoms, cyano groups, aldehyde groups, carbonyl groups, carboxy groups, oxycarbonyl groups, ester groups, carbamoyl groups, amide groups, sulfonyl groups, sulfonate ester groups, sulfonamide groups, imino groups, amino groups, nitro groups, silyl groups, siloxanyl groups, boryl groups, and phosphine oxide groups. These substituents may also be further substituted with the above-mentioned substituents.

An alkyl group refers to a saturated aliphatic hydrocarbon group such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, or tert-butyl group, which may or may not have a substituent. If substituted, the additional substituent is not particularly limited, and examples include alkyl groups, halogens, aryl groups, and heteroaryl groups, as will be described below. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 1 to 20, more preferably 1 to 8, in terms of availability and cost.

A cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as a cyclopropyl group, cyclohexyl group, norbornyl group, or adamantyl group, which may or may not have a substituent. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 3 to 20.

A heterocyclic group refers to an aliphatic ring containing atoms other than carbon within the ring, such as a pyran ring, piperidine ring, or cyclic amide, which may or may not have a substituent. The number of carbon atoms in the heterocyclic group is not particularly limited, but is preferably in the range of 2 to 20.

An alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as a vinyl group, allyl group, or butadienyl group, which may or may not have a substituent. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 to 20.

A cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, cyclopentadienyl group, or cyclohexenyl group, which may or may not have a substituent. The number of carbon atoms in the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 to 20.

An alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as an ethynyl group, which may or may not have a substituent. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 to 20.

An alkoxy group is a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond, such as a methoxy group, ethoxy group, or propoxy group. This aliphatic hydrocarbon group may or may not have a substituent. The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably in the range of 1 to 20.

An alkylthio group is an alkoxy group in which the oxygen atom in the ether bond is replaced with a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. The number of carbon atoms in the alkylthio group is not particularly limited, but is preferably in the range of 1 to 20.

An aryl ether group is a functional group, such as a phenoxy group, to which an aromatic hydrocarbon group is bonded via an ether bond. The aromatic hydrocarbon group may or may not have a substituent. The number of carbon atoms in the aryl ether group is not particularly limited, but is preferably in the range of 6 to 40.

An aryl thioether group is an aryl ether group in which the oxygen atom in the ether bond is replaced with a sulfur atom. The aromatic hydrocarbon group in the aryl thioether group may or may not have a substituent. The number of carbon atoms in the aryl thioether group is not particularly limited, but is preferably in the range of 6 to 40.

Aryl groups include aromatic hydrocarbon groups such as phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, phenanthryl, anthracenyl, benzophenanthryl, benzanthracenyl, chrysenyl, pyrenyl, fluoranthenyl, triphenylenyl, benzofluoranthenyl, dibenzoanthracenyl, perylenyl, and helicenyl. Among these, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthracenyl, pyrenyl, fluoranthenyl, and triphenylenyl are preferred. The aryl group may or may not have a substituent. The number of carbon atoms in the aryl group is not particularly limited, but is preferably in the range of 6 to 40, more preferably 6 to 30.

Furthermore, as the aryl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, or an anthracenyl group is preferred, with a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group being more preferred. Phenyl groups, biphenyl groups, and terphenyl groups are even more preferred, with a phenyl group being particularly preferred.

When each of the substituents is further substituted with an aryl group, the aryl group is preferably a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, or an anthracenyl group, more preferably a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group. A phenyl group is particularly preferred.

Heteroaryl groups include, for example, pyridyl groups, furanyl groups, thienyl groups, quinolinyl groups, isoquinolinyl groups, pyrazinyl groups, pyrimidyl groups, pyridazinyl groups, triazinyl groups, naphthyridinyl groups, cinnolinyl groups, phthalazinyl groups, quinoxalinyl groups, quinazolinyl groups, benzofuranyl groups, benzothienyl groups, indolyl groups, dibenzofuranyl groups, dibenzothienyl groups, carbazolyl groups, and benzocarbazolyl groups. It refers to a cyclic aromatic group having one or more atoms other than carbon in the ring, such as a benzoyl group, a carbolinyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a dihydroindenocarbazolyl group, a benzoquinolinyl group, an acridinyl group, a dibenzoacridinyl group, a benzimidazolyl group, an imidazopyridyl group, a benzoxazolyl group, a benzothiazolyl group, or a phenanthrolinyl group. However, a naphthyridinyl group refers to a 1,5-naphthyridinyl group, a 1,6-naphthyridinyl group, a 1,7-naphthyridinyl group, a 1,8-naphthyridinyl group, a 2,6-naphthyridinyl group, or a 2,7-naphthyridinyl group. The heteroaryl group may or may not have a substituent. The number of carbon atoms in the heteroaryl group is not particularly limited, but is preferably in the range of 2 to 40, more preferably 2 to 30.

Furthermore, as heteroaryl groups, pyridyl groups, furanyl groups, thienyl groups, quinolinyl groups, pyrimidyl groups, triazinyl groups, benzofuranyl groups, benzothienyl groups, indolyl groups, dibenzofuranyl groups, dibenzothienyl groups, carbazolyl groups, benzimidazolyl groups, imidazopyridyl groups, benzoxazolyl groups, benzothiazolyl groups, and phenanthrolinyl groups are preferred, with pyridyl groups, furanyl groups, thienyl groups, and quinolinyl groups being more preferred. A pyridyl group is particularly preferred.

When each substituent is further substituted with a heteroaryl group, the heteroaryl group is preferably a pyridyl group, a furanyl group, a thienyl group, a quinolinyl group, a pyrimidyl group, a triazinyl group, a benzofuranyl group, a benzothienyl group, an indolyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a benzimidazolyl group, an imidazopyridyl group, a benzoxazolyl group, a benzothiazolyl group, or a phenanthrolinyl group, with a pyridyl group, a furanyl group, a thienyl group, or a quinolinyl group being more preferred. A pyridyl group is particularly preferred.

Halogen refers to an atom selected from fluorine, chlorine, bromine, and iodine. Furthermore, carbonyl groups, carboxy groups, oxycarbonyl groups, ester groups, carbamoyl groups, amide groups, and imino groups may or may not have a substituent. Examples of substituents include alkyl groups, cycloalkyl groups, aryl groups, and heteroaryl groups, and these substituents may be further substituted.

The sulfonyl group, sulfonate ester group, and sulfonamide group are groups represented by -S(=O) _2R10 , -S(=O) _2OR10 , and -S(=O) _2NR10R11 ^, respectively. ^R10 and ^R11 are each a hydrogen atom or ^a group selected from ^the same group as ^the above-mentioned substituents when substituted.

The amino group is a substituted or unsubstituted amino group. In the case of substitution, examples of the substituent include an aryl group, a heteroaryl group, a straight-chain alkyl group, and a branched alkyl group. Preferred aryl and heteroaryl groups are a phenyl group, a naphthyl group, a pyridyl group, and a quinolinyl group. These substituents may be further substituted. The number of carbon atoms is not particularly limited, but is preferably in the range of 2 to 50, more preferably 6 to 40, and particularly preferably 6 to 30.

The silyl group refers to, for example, alkylsilyl groups such as trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, propyldimethylsilyl, and vinyldimethylsilyl, and arylsilyl groups such as phenyldimethylsilyl, tert-butyldiphenylsilyl, triphenylsilyl, and trinaphthylsilyl. The substituent on the silicon atom may be further substituted. The number of carbon atoms in the silyl group is not particularly limited, but is preferably in the range of 1 to 30.

A siloxanyl group refers to a silicon compound group connected via an ether bond, such as a trimethylsiloxanyl group. The substituent on the silicon may be further substituted. A boryl group refers to a substituted or unsubstituted boryl group. In the case of substitution, examples of the substituent include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group, and a hydroxyl group. Of these, an aryl group and an aryl ether group are preferred.

The phosphine oxide group is a group represented by -P(=O)R ¹⁰ R ^11. R ¹⁰ and R ¹¹ of the phosphine oxide group are each a hydrogen atom or selected from the same group as the substituents when substituted, as described above.

Furthermore, in each of the compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4), any two adjacent substituents may be bonded to each other to form a conjugated or non-conjugated fused ring or aliphatic ring. The constituent elements of such a fused ring or aliphatic ring may include, in addition to carbon, an element selected from nitrogen, oxygen, sulfur, phosphorus, and silicon. Furthermore, the above-mentioned fused ring or aliphatic ring may be further fused with another ring.

The compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4) each exhibit emission of high color purity due to the interaction between the electron donor atom and the electron acceptor atom.

In addition, in each of the compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4), the electron donor atom and the electron acceptor atom are located in close proximity within the molecule. Compounds having such partial structures are compounds that can separate the HOMO orbital and the LUMO orbital through the multiple resonance effect. In organic light-emitting materials containing these compounds, the energy levels of the singlet excited state and the triplet excited state can be brought closer together.

The compounds represented by general formula (2), general formula (3), and general formula (4) each exhibit high fluorescence quantum yields and have narrow half-widths of the emission spectra at the peak emission wavelengths, thereby achieving both efficient color conversion and high color purity.

Furthermore, by introducing appropriate substituents into appropriate positions, various characteristics and physical properties such as luminous efficiency, color purity, thermal stability, light stability, and dispersibility can be adjusted for each of the compounds represented by general formula (2), general formula (3), and general formula (4).

In each of general formulas (2), (3), and (4), the substituent Ra, including the substituent substituting the substituent Ra, is preferably a group having 6 to 40 carbon atoms. The substituent Ra is preferably a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group, and more preferably a substituted or unsubstituted aryl group. Examples of substituted or unsubstituted aryl groups include substituted or unsubstituted phenyl groups, substituted or unsubstituted biphenyl groups, substituted or unsubstituted fluorenyl groups, substituted or unsubstituted naphthyl groups, and substituted or unsubstituted phenanthrenyl groups. Of these, substituted or unsubstituted phenyl groups are more preferred.

In the compounds represented by general formula (2), general formula (3), and general formula (4), when the π-conjugated system expands, reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, thereby further improving durability, and therefore they are preferred as luminescent materials contained in the color conversion material of the present invention. From this perspective, in general formula (2), Z ¹ and Z ² are preferably oxygen atoms or NRa, because the π-conjugated system expands efficiently. Similarly, in general formula (2), E is preferably a boron atom, and in general formula (3), E ¹ and E ² are preferably BRa, because the π-conjugated system expands efficiently. Similarly, in general formula (4), Z ³ and Z ⁴ are preferably oxygen atoms or NRa, because the π-conjugated system expands efficiently.

In addition, in general formula (2) and general formula (3), ring Za, ring Zb, and ring Zc are preferably benzene rings, as this allows the π-conjugated system to expand efficiently. Similarly, in general formula (4), ring Zd, ring Ze, ring Zf, ring Zg, ring Zh, and ring Zi are preferably benzene rings, as this allows the π-conjugated system to expand efficiently. In addition, in general formula (4), it is also preferable that at least one of ring Ze and ring Zh has an aryl group, as this allows the π-conjugated system to expand efficiently. In particular, in general formula (4), ring Ze and ring Zh are preferably both benzene rings substituted with substituted or unsubstituted aryl groups.

Each of the compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4) can be separated by the multiple resonance effect by optimally arranging the electron-donating amine nitrogen atom and the electron-accepting boron atom, as described in, for example, Adv. Mater., 2016, 28, 2777-2781. From the viewpoint of clearly separating the HOMO orbital and the LUMO orbital and bringing the energy levels of the singlet excited state and the triplet excited state closer together, in general formula (2), it is preferable that E is a boron atom with strong electron-accepting properties, and that both Z ¹ and Z ² are NRa groups with strong electron-donating properties. Similarly, in general formula (4), it is preferable that both Z ³ and Z ⁴ are NRa groups with strong electron-donating properties.

Furthermore, due to the multiple resonance effect, the emission spectra of each of the compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4) are sharper than those of compounds in which an electron donor skeleton and an electron acceptor skeleton are combined. Therefore, when the light-emitting material contained in the color-converting composition of the present invention is a compound represented by any one of general formulas (2), (3), and (4), light emission with high color purity can be obtained. In other words, the compounds having a structure represented by general formula (2), the compounds having a structure represented by general formula (3), and the compounds having a structure represented by general formula (4) are advantageous for improving the color gamut of displays and are therefore preferred as such light-emitting materials.

Furthermore, in compounds having a structure represented by general formula (2) or (3), rings Za, Zb, and Zc are present around the E atom in general formula (2) or (3), where the LUMO orbital is mainly localized, and therefore the LUMO orbital can be delocalized from the E atom to each ring. By delocalizing the LUMO orbital, the multiple resonance effect works efficiently, resulting in emission of higher color purity. Note that the E atom is the E atom in general formula (2), and each of the ^E1 and ^E2 atoms in general formula (3). Similarly, in compounds having a structure represented by general formula (4), rings Zd, Ze, Zf, Zg, Zh, and Zi are present around the boron atom, where the LUMO orbital is mainly localized, and therefore the LUMO orbital can be delocalized from the boron atom to each ring. By delocalizing the LUMO orbital, the multiple resonance effect works efficiently, resulting in emission of higher color purity.

Furthermore, in general formula (2) and general formula (3), it is more preferable that the substituent Ra forms a structure bonded to at least one ring selected from ring Za, ring Zb, and ring Zc. This is because the bonding of the substituent Ra to at least one ring selected from ring Za, ring Zb, and ring Zc is expected to further enhance the steric protection effect of E in general formula (2) and ^E1 and ^E2 in general formula (3), thereby further improving the effect of suppressing a decrease in fluorescence quantum yield. Similarly, in general formula (4), it is also preferable that the substituent Ra forms a structure bonded to at least one ring selected from ring Zd, ring Ze, ring Zf, ring Zg, ring Zh, and ring Zi, because this is expected to further enhance the steric protection effect of the boron atom in general formula (4) and further improve the effect of suppressing a decrease in fluorescence quantum yield.

The color-converting composition of the present invention preferably contains the following luminescent material (a). The luminescent material (a) is a luminescent material that, when excited with excitation light having a wavelength in the range of 400 nm to 500 nm, emits light with a peak wavelength observed in the range of 500 nm to less than 580 nm. Hereinafter, the light emitted with a peak wavelength in the range of 500 nm to less than 580 nm will be referred to as "green light" as necessary. Generally, the greater the energy of excitation light, the more likely it is to cause material decomposition. However, excitation light having a wavelength in the range of 400 nm to 500 nm has relatively low excitation energy. Therefore, green light with good color purity can be obtained without causing decomposition of the luminescent material (a) in the color-converting composition.

The color-converting composition of the present invention preferably contains the above-mentioned luminescent material (a) and the following luminescent material (b). As described above, luminescent material (a) is a luminescent material that emits light with a peak wavelength of 500 nm or more and less than 580 nm when excited with excitation light having a wavelength in the range of 400 nm or more and 500 nm or less. Luminescent material (b) is a luminescent material that emits light with a peak wavelength observed in the range of 580 nm or more and 750 nm or less when excited with at least one of excitation light having a wavelength in the range of 400 nm or more and 500 nm or less and the emission from luminescent material (a). Hereinafter, the emission observed with a peak wavelength in the range of 580 nm or more and 750 nm or less will be referred to as "red emission" as necessary.

A portion of the excitation light in the wavelength range of 400 nm or more and 500 nm or less is partially transmitted through the color conversion composition or color conversion member (a member containing the color conversion composition or a cured product thereof) of the present invention. Therefore, when a blue LED with a sharp emission peak is used, a sharply shaped emission spectrum is exhibited in each of the blue, green, and red colors, making it possible to obtain white light with excellent color purity. As a result, particularly in displays, it is possible to efficiently create a wider color gamut with even more vivid colors. Furthermore, in lighting applications, the emission characteristics, particularly in the green and red regions, are improved compared to white LEDs that combine the currently mainstream blue LED with a yellow phosphor, making it possible to obtain a desirable white light source with improved color rendering.

Examples of the luminescent material (a) include coumarin derivatives such as coumarin 6, coumarin 7, and coumarin 153; cyanine derivatives such as indocyanine green; fluorescein derivatives such as fluorescein, fluorescein isothiocyanate, and carboxyfluorescein diacetate; phthalocyanine derivatives such as phthalocyanine green; perylene derivatives such as diisobutyl-4,10-dicyanoperylene-3,9-dicarboxylate; pyrromethene derivatives, stilbene derivatives, oxazine derivatives, naphthalimide derivatives, pyrazine derivatives, benzimidazole derivatives, benzoxazole derivatives, benzothiazole derivatives, imidazopyridine derivatives, azole derivatives, compounds having fused aryl rings such as anthracene and their derivatives, aromatic amine derivatives, and organometallic complex compounds. Furthermore, compounds having a partial structure represented by the above-mentioned general formula (1), compounds having a structure represented by general formula (2), compounds having a structure represented by general formula (3), and compounds having a structure represented by general formula (4) also exhibit light emission with high color purity and are therefore suitable as light-emitting materials contained in the color-converting composition of the present invention. The color-converting composition of the present invention may contain two or more of these as at least one organic light-emitting material.

Examples of the luminescent material (b) include cyanine derivatives such as 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostillyl)-4H-pyran; rhodamine derivatives such as rhodamine B, rhodamine 6G, rhodamine 101, and sulforhodamine 101; pyridine derivatives such as 1-ethyl-2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-pyridinium-perchlorate; perylene derivatives such as N,N'-bis(2,6-diisopropylphenyl)-1,6,7,12-tetraphenoxyperylene-3,4:9,10-bisdicarboimide; porphyrin derivatives, pyrromethene derivatives, oxazine derivatives, pyrazine derivatives; compounds having fused aryl rings such as naphthacene and dibenzodiindenoperylene, and their derivatives; and organometallic complex compounds. Furthermore, compounds having a partial structure represented by the above-mentioned general formula (1), compounds having a structure represented by general formula (2), compounds having a structure represented by general formula (3), and compounds having a structure represented by general formula (4) also exhibit light emission with high color purity and are therefore suitable as light-emitting materials contained in the color-converting composition of the present invention. The color-converting composition of the present invention may contain two or more of these as at least one organic light-emitting material.

In one embodiment of the color conversion composition or color conversion member of the present invention, the peak wavelength of the fluorescent emission spectrum of at least one organic light-emitting material contained in the color conversion composition or color conversion member in a dilute toluene solution is in the wavelength range of 500 nm or more. In this case, the long-term maintenance rate of emission in the green or red region is improved. For this reason, it is preferable that the peak wavelength of the color conversion composition or color conversion member of the present invention is in the wavelength range of 500 nm or more.

In another embodiment of the color conversion composition or color conversion member of the present invention, the peak wavelength of the fluorescent emission spectrum of at least one organic light-emitting material contained in the color conversion composition or color conversion member in a dilute toluene solution is in the wavelength range of 500 nm or more and less than 580 nm. In this case, the long-term maintenance rate of emission in the green region is improved. For this reason, it is preferable that the peak wavelength of the color conversion composition or color conversion member of the present invention is in the wavelength range of 500 nm or more and less than 580 nm.

In yet another embodiment of the color conversion composition or color conversion member of the present invention, the peak wavelength of the fluorescent emission spectrum of at least one organic light-emitting material contained in the color conversion composition or color conversion member in a dilute toluene solution is in the wavelength range of 580 nm or more and less than 750 nm. In this case, the long-term maintenance rate of light emission in the red region is improved. For this reason, it is preferable that the peak wavelength of the color conversion composition or color conversion member of the present invention is in the wavelength range of 580 nm or more and less than 750 nm.

As mentioned above, in order to improve color reproducibility, it is preferable that the half-width of the emission spectrum of each of the blue, green, and red colors be small. In particular, small half-widths of the emission spectrum of green light and red light are effective in improving color reproducibility. For example, the half-width of the emission spectrum of the above-mentioned luminescent material (a) is preferably 50 nm or less, more preferably 40 nm or less, even more preferably 35 nm or less, and particularly preferably 30 nm or less. The half-width of the emission spectrum of the above-mentioned luminescent material (b) is preferably 60 nm or less, more preferably 50 nm or less, even more preferably 45 nm or less, and particularly preferably 40 nm or less.

The content of the luminescent material in the color-converting composition of the present invention can be selected depending on the molar absorption coefficient, fluorescence quantum yield, and absorption intensity at the excitation wavelength of the compound, as well as the thickness and transmittance of the color-converting member (color-converting sheet, etc.) to be produced. Here, the content of the luminescent material refers to the total content when the color-converting composition of the present invention contains two or more luminescent materials. The content of the luminescent material is preferably 1.0 × 10 ^-2 to 5 parts by weight per 100 parts by weight of the binder resin contained in the color-converting composition of the present invention.

Furthermore, when the color-converting composition of the present invention contains both a luminescent material (a) that emits green light and a luminescent material (b) that emits red light, a portion of the green light is converted to red light, and therefore the content w _a of the luminescent material (a) and the content w _b of the luminescent material (b) preferably satisfy the relationship w _a ≧ w _b . Furthermore, the content ratio w _a : w _b of these luminescent materials (a) and (b) is preferably 200:1 to 3:1. However, the contents w _a and w _b are expressed in weight percent relative to the weight of the binder resin contained in the color-converting composition of the present invention.

The color conversion composition or color conversion member of the present invention may contain other compounds as needed in addition to the organic light-emitting material satisfying the above-mentioned formula (A-1). For example, to increase the efficiency of energy transfer from excitation light to the light-emitting material, the color conversion composition or color conversion member of the present invention may contain an assist dopant. Furthermore, if it is desired to add a different light-emitting color, the color conversion composition or color conversion member of the present invention may further contain the above-mentioned organic light-emitting material or a known light-emitting material such as an inorganic phosphor, a fluorescent pigment, a fluorescent dye, or quantum dots.

<Binder resin>
The color-changing composition and color-changing member of the present invention each contain a binder resin in addition to at least one organic light-emitting material described above. Materials with excellent moldability, transparency, heat resistance, and the like are preferably used as the binder resin. Examples of binder resins include known materials such as photocurable resist materials having reactive vinyl groups, such as acrylic acid-based, methacrylic acid-based, polyvinyl cinnamate-based, and cyclic rubber-based materials, epoxy resins, silicone resins (including organopolysiloxane cured products (crosslinked products) such as silicone rubber and silicone gel), urea resins, fluororesins, polycarbonate resins, acrylic resins, urethane resins, melamine resins, polyvinyl resins, polyamide resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, aliphatic ester resins, aromatic ester resins, aliphatic polyolefin resins, and aromatic polyolefin resins. Furthermore, mixtures or copolymers of these resins may also be used as the binder resin. By appropriately designing these resins, binder resins useful for the color-changing composition and color-changing material of the present invention can be obtained.

Among these resins, from the viewpoints of transparency and dispersibility of the light-emitting material, acrylic resin, copolymer resin containing an acrylic ester or methacrylic ester moiety, polyester resin, cycloolefin resin, epoxy resin, or silicone resin is preferred. Furthermore, from the viewpoint of heat resistance, hydrogenated styrene-based resins, resins having a fluorene skeleton, and copolymer resins containing these resins can also be suitably used.

Examples of binder resins include thermosetting resins, photocurable resins, and thermoplastic resins. Thermoplastic resins have few reactive functional groups and contain few reactive impurities such as polymerization initiators and crosslinking agents, making them less likely to inhibit the luminescence of the luminescent material and therefore suitable for use as binder resins. From the standpoint of heat resistance, thermosetting resins and photocurable resins are also suitable for use as binder resins.

When the binder resin is a thermoplastic resin, the glass transition temperature (Tg) of the binder resin is not particularly limited, but is preferably 30°C or higher and 180°C or lower. When the Tg of the binder resin is 30°C or higher, molecular motion of the binder resin due to heat from incident light from a light source or heat generated by operating the device is suppressed, thereby suppressing changes in the dispersion state of the luminescent material in the binder resin, thereby preventing deterioration of the durability of the color-converting composition and color-converting member of the present invention. Furthermore, when the Tg of the binder resin is 180°C or lower, the flexibility of the binder resin can be ensured when molded into a sheet or the like. The Tg of the binder resin is more preferably 50°C or higher and 170°C or lower, even more preferably 70°C or higher and 160°C or lower, and particularly preferably 90°C or higher and 150°C or lower. The glass transition temperature of the thermoplastic resin can be measured using a commercially available measuring device (for example, a differential scanning calorimeter manufactured by Seiko Instruments Inc. (product name: DSC6220, heating rate: 0.5°C/min)).

In one embodiment of the present invention, the binder resin is a polymer or hydrogenation product of at least one monomer selected from the group consisting of acrylic acid esters, methacrylic acid esters, and styrene, and preferably has a Tg of 100°C or higher. In this case, the Tg is more preferably 110°C or higher, and particularly preferably 120°C or higher. These resins can be obtained by known methods, such as copolymerizing the raw material monomers in the presence of a polymerization initiator, or by polymerizing and then converting the structure through a chemical reaction such as an addition reaction, substitution reaction, or oxidation-reduction reaction. Commercially available binder resins can also be used.

<Additives>
Each of the color-converting compositions and color-converting members of the present invention may contain, as necessary, other components (e.g., additives) in addition to the at least one organic light-emitting material and binder resin described above. Examples of additives include fillers, light stabilizers, antioxidants, processing and heat stabilizers, light resistance stabilizers such as UV absorbers, dispersants and leveling agents for stabilizing coated films, scattering agents, plasticizers, crosslinking agents such as epoxy compounds, curing agents such as amines, acid anhydrides, and imidazoles, pigments, and adhesion aids such as silane coupling agents as film surface modifiers.

Examples of fillers include fine particles such as fumed silica, glass powder, and quartz powder, as well as fine particles of titanium oxide, zirconia oxide, barium titanate, zinc oxide, and silicone. The color-changing composition and color-changing member of the present invention may each contain two or more of these fillers.

Light stabilizers include, but are not limited to, tertiary amines, catechol derivatives, complexes containing at least one transition metal selected from the group consisting of nickel (Ni), scandium (Sc), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), yttrium (Y), zirconium (Zr), molybdenum (Mo), silver (Ag), and lanthanides, or salts with organic acids. These light stabilizers may be used alone or in combination.

Examples of antioxidants include, but are not limited to, phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol and 2,6-di-tert-butyl-4-ethylphenol. These antioxidants may be used alone or in combination.

Examples of processing and heat stabilizers include, but are not limited to, phosphorus-based stabilizers such as tributyl phosphite, tricyclohexyl phosphite, triethyl phosphine, and diphenylbutyl phosphine. These stabilizers may be used alone or in combination.

Examples of light resistance stabilizers include, but are not limited to, benzotriazoles such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole. These light resistance stabilizers may be used alone or in combination.

Preferably, the scattering particles are inorganic particles with a refractive index of 1.7 to 2.8. Examples of such inorganic particles include titania, zirconia, alumina, ceria, tin oxide, indium oxide, iron oxide, zinc oxide, aluminum nitride, aluminum, tin, titanium or zirconium sulfide, and titanium or zirconium hydroxide.

In the color-converting composition of the present invention, the content of these additives can be set depending on the molar extinction coefficient, fluorescence quantum yield, and absorption intensity at the excitation wavelength of the compound, as well as the size, thickness, and transmittance of the color-converting component to be fabricated. The content (lower limit) of these additives is preferably 1.0 × 10 ^-3 parts by weight or more, more preferably 1.0 × 10 ^-2 parts by weight or more, and particularly preferably 1.0 × 10 ^-1 parts by weight or more, per 100 parts by weight of the binder resin. The content (upper limit) of these additives is preferably 30 parts by weight or less, more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less, per 100 parts by weight of the binder resin.

<Solvent>
Each of the color-changing compositions and color-changing members of the present invention may further contain a solvent in addition to the at least one organic light-emitting material and binder resin described above. A solvent that can adjust the viscosity of the resin in a fluid state and that does not excessively affect the light emission and durability of the light-emitting substance is preferred. Examples of such solvents include water, 2-propanol, ethanol, toluene, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, hexane, cyclohexane, tetrahydrofuran, acetone, terpineol, Texanol, 1,2-dimethoxyethane, methyl cellosolve, ethyl cellosolve, butyl carbitol, butyl carbitol acetate, 1-methoxy-2-propanol, and propylene glycol monomethyl ether acetate. Each of the color-changing compositions and color-changing members of the present invention may use one of these solvents, or two or more of these solvents may be mixed and used. Among these solvents, toluene, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran are preferably used because they leave little residual solvent after drying.

In the color conversion member of the present invention, the amount of residual solvent in the color conversion layer of the color conversion member (the amount of solvent remaining in the color conversion layer after drying) is preferably 3.0% by mass or less, more preferably 1.0% by mass or less, and particularly preferably 0.5% by mass or less, from the viewpoint of further improving the durability of the color conversion member. The amount of residual solvent in the color conversion layer can be measured by gas chromatography.

<Method of manufacturing color-changing composition and color-changing member>
An example of a method for producing a color-changing composition according to an embodiment of the present invention is described below. In this method, the organic light-emitting material, binder resin, and, if necessary, other additives and solvents are mixed to a predetermined composition, and then the mixture is homogeneously mixed or kneaded using a stirrer/kneader to obtain a color-changing composition. Examples of stirrers/kneaders include homogenizers, planetary stirrers, three-roller stirrers, ball mills, planetary ball mills, and bead mills. After mixing or dispersing, or during the mixing or dispersing process, degassing is preferably performed under vacuum or reduced pressure conditions. It is also possible to premix certain components or to perform treatments such as aging. It is also possible to remove the solvent using an evaporator to achieve a desired solids concentration.

The color conversion member of the present invention comprises the color conversion composition described above or a cured product thereof. The shape of the color conversion member is not particularly limited. For example, the shape of the color conversion member may be layered, particulate, fibrous, or the like. One embodiment of the color conversion member of the present invention is a color conversion sheet. The color conversion sheet has a color conversion layer that contains the color conversion composition of the present invention or a layer that contains a cured product formed by curing the color conversion composition.

The color conversion member of the present invention may have a single color conversion layer or multiple color conversion layers. When the color conversion member has multiple color conversion layers, the multiple color conversion layers may be laminated directly on top of each other, or may be laminated via an intermediate layer such as an adhesive layer. Furthermore, the color conversion member of the present invention may have a substrate layer or a barrier layer as necessary, and may have two or more of these layers.

The substrate layer of the color conversion member of the present invention is not particularly limited and can be a layer made of a known substrate such as metal, film, glass, ceramic, or paper. Among these, glass or resin film is preferably used. Resin films are preferably made of resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide, polycarbonate, polypropylene, polyimide, aramid, and silicone. To facilitate easy peeling of the sheet, the surface of the substrate layer may be pre-treated with a release agent. Similarly, to improve adhesion between layers, the surface of the substrate layer may be pre-treated with an easy-adhesion agent.

When the substrate layer is a film-like layer, there are no particular restrictions on the thickness of the substrate layer, but the lower limit is preferably 12 μm or more, and more preferably 38 μm or more. The upper limit is preferably 5000 μm or less, and more preferably 3000 μm or less.

In addition, the substrate constituting the substrate layer may be, for example, a barrier film, a light guide plate, a diffusion plate, a diffusion film, a prism sheet, a reflective polarizing film, a wavelength-selective reflection film, a wavelength-selective transmission film, or a wavelength-selective absorption film.

The barrier layer of the color conversion member of the present invention is preferably one that prevents oxygen, moisture, heat, etc. from penetrating into the color conversion layer. The color conversion member of the present invention may have two or more such barrier layers. For example, the color conversion member of the present invention may have a barrier layer on both sides of the color conversion layer, or a barrier layer on one side of the color conversion layer.

One aspect of the color conversion member of the present invention is that the color conversion member has an oxygen barrier layer. Having an oxygen barrier layer in the color conversion member of the present invention is preferable because it can suppress oxidative degradation of the light-emitting material in the color conversion layer due to singlet oxygen generated by a dye-sensitization mechanism or the like. Furthermore, organic light-emitting materials satisfying the above-mentioned formula (A-1) exhibit significantly superior durability compared to conventional organic light-emitting materials in the absence of oxygen, making them preferable as organic light-emitting materials to be contained in the color conversion layer of the color conversion member. The reason for such excellent durability is that organic light-emitting materials satisfying the above-mentioned formula (A-1) have a long lifetime and can quickly convert a triplet excited state, which is prone to reacting with surrounding molecules, to a singlet excited state, thereby making it less likely for the organic light-emitting material to deteriorate due to reactions between the triplet excited state and surrounding molecules.

Examples of oxygen barrier layers include layers composed of inorganic oxides such as silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, zinc oxide, tin oxide, indium oxide, yttrium oxide, and magnesium oxide; inorganic nitrides such as silicon nitride, aluminum nitride, titanium nitride, and silicon carbonitride; thin metal oxide or metal nitride films containing these with added elements; and films containing various resins such as polyvinylidene chloride, acrylic resins, silicone resins, melamine resins, urethane resins, fluorine resins, and polyvinyl alcohol resins such as saponified vinyl acetate. The oxygen barrier layer may contain two or more of these.

Typical structural examples of the color conversion member of the present invention include the structures of the color conversion sheets shown below as first to sixth examples. Note that the color conversion member of the present invention is not limited to the structural examples of the color conversion sheets shown below.

Figure 1 is a schematic cross-sectional view showing a first example of a color conversion member according to an embodiment of the present invention. As shown in Figure 1, the first example color conversion member 1A is a color conversion sheet having a laminated structure of a substrate layer 10 and a color conversion layer 11. This color conversion layer 11 is a layer containing the color conversion composition of the present invention and is obtained, for example, by curing the color conversion composition of the present invention. In this structural example of color conversion member 1A, the color conversion layer 11 is laminated on the substrate layer 10.

Figure 2 is a schematic cross-sectional view showing a second example of a color conversion member according to an embodiment of the present invention. As shown in Figure 2, the second example color conversion member 1B is a color conversion sheet having a laminated structure of multiple base layers 10A, 10B and a color conversion layer 11. In this structural example of color conversion member 1B, the color conversion layer 11 is sandwiched between multiple base layers 10A, 10B.

Figure 3 is a schematic cross-sectional view showing a third example of a color conversion member according to an embodiment of the present invention. As shown in Figure 3, the third example color conversion member 1C is a color conversion sheet having a laminated structure of multiple base layers 10A, 10B, a color conversion layer 11, and multiple barrier layers 12A, 12B. In this structural example of color conversion member 1C, color conversion layer 11 is sandwiched between multiple barrier layers 12A, 12B, and the laminate of color conversion layer 11 and multiple barrier layers 12A, 12B is further sandwiched between multiple base layers 10A, 10B. Each of these multiple barrier layers 12A, 12B is an oxygen barrier layer that prevents deterioration of color conversion layer 11 due to oxygen in color conversion member 1C. Note that each of these multiple barrier layers 12A, 12B is not limited to being an oxygen barrier layer and may be a layer that prevents deterioration of color conversion layer 11 due to moisture or heat.

Figure 4 is a schematic cross-sectional view showing a fourth example of a color conversion member according to an embodiment of the present invention. As shown in Figure 4, the fourth example color conversion member 1D is a color conversion sheet having a laminated structure in which multiple color conversion layers 11A, 11B are sandwiched between multiple base layers 10A, 10B. In this structural example of color conversion member 1D, a laminate of multiple color conversion layers 11A, 11B is formed by stacking color conversion layer 11A and color conversion layer 11B in this order on base layer 10A, and then another base layer 10B is stacked on top of this color conversion layer 11B. In other words, color conversion member 1D comprises multiple base layers 10A, 10B and multiple color conversion layers 11A, 11B, and the multiple color conversion layers 11A, 11B are sandwiched between the multiple base layers 10A, 10B.

Figure 5 is a schematic cross-sectional view showing a fifth example of a color conversion member according to an embodiment of the present invention. As shown in Figure 5, the fifth example color conversion member 1E is a color conversion sheet having a laminated structure in which an intermediate layer 13 is sandwiched between multiple color conversion layers 11A, 11B, and the laminate of these multiple color conversion layers 11A, 11B and intermediate layer 13 is sandwiched between multiple base layers 10A, 10B. In this structural example of color conversion member 1E, the laminate of multiple color conversion layers 11A, 11B and intermediate layer 13 is laminated on base layer 10A in the order color conversion layer 11A, intermediate layer 13, and color conversion layer 11B, and another base layer 10B is further laminated on top of this color conversion layer 11B. That is, color conversion member 1E comprises multiple base layers 10A, 10B, multiple color conversion layers 11A, 11B, and an intermediate layer 13, and is sandwiched between these multiple base layers 10A, 10B, containing a layered structure of color conversion layer 11B/intermediate layer 13/color conversion layer 11A.

Figure 6 is a schematic cross-sectional view showing a sixth example of a color conversion member according to an embodiment of the present invention. As shown in Figure 6, the sixth example color conversion member 1F is a color conversion sheet having a laminated structure in which an intermediate layer 13 is sandwiched between multiple color conversion layers 11A, 11B, a laminate of these multiple color conversion layers 11A, 11B and the intermediate layer 13 is sandwiched between multiple barrier layers 12A, 12B, and a laminate of these multiple color conversion layers 11A, 11B, the intermediate layer 13, and the multiple barrier layers 12A, 12B is sandwiched between multiple base layers 10A, 10B. These multiple barrier layers 12A, 12B are formed so as to sandwich the laminate of the multiple color conversion layers 11A, 11B with the intermediate layer 13 interposed between them on both sides in the stacking direction. In this structural example of color conversion member 1F, a barrier layer 12A, a color conversion layer 11A, an intermediate layer 13, a color conversion layer 11B, and a barrier layer 12B are laminated in this order on a base layer 10A. As a result, a laminate with a layered structure of barrier layer 12B/color conversion layer 11B/intermediate layer 13/color conversion layer 11A/barrier layer 12A is formed on this base material layer 10A. Furthermore, as shown in Figure 6, base material layer 10B is laminated on top of barrier layer 12B, which is at the top of the laminate in the stacking direction.

In each of the color conversion members 1A, 1B, 1C, 1D, 1E, and 1F shown in Figures 1 to 6, the layers of the laminated structure may be in direct contact with each other or may be laminated via an adhesive layer (not shown).

Another embodiment of the color conversion member of the present invention (different from the color conversion sheet described above) is a color conversion substrate. This color conversion substrate, for example, comprises multiple color conversion layers on a substrate. Although not specifically shown, partition walls may be formed on the color conversion substrate, and the color conversion layers may be disposed between the partition walls (in recesses) in the color conversion substrate.

Depending on the required functions, the color conversion member of the present invention may further include an auxiliary layer having a light diffusion layer, an adhesive layer, anti-reflection function, anti-glare function, anti-reflection and anti-glare function, hard coating function (friction resistance function), anti-static function, anti-fouling function, electromagnetic wave shielding function, infrared blocking function, ultraviolet blocking function, polarizing function, or color-tuning function.

The method for producing a color conversion member according to an embodiment of the present invention is not particularly limited as long as it can mold the color conversion composition of the present invention into the desired shape. For example, a method can be used in which the color conversion layer of the color conversion member of the present invention is formed by applying the color conversion composition of the present invention to a substrate and drying it. When the binder resin contained in the color conversion composition of the present invention is a thermosetting resin, the color conversion layer can be formed by applying the color conversion composition to a base such as a substrate and then heat-curing the color conversion composition. When the binder resin contained in the color conversion composition of the present invention is a photocurable resin, the color conversion layer can be formed by applying the color conversion composition to a base such as a substrate and then photo-curing the color conversion composition. Other examples include a method in which the color conversion composition of the present invention is kneaded while heating and then molded using an extruder, or a method in which the color conversion composition of the present invention is placed in a mold and molded by heating, cooling, drying, etc.

In the above-described method for manufacturing a color conversion member, the color conversion composition can be applied using a reverse roll coater, blade coater, comma coater, slit die coater, direct gravure coater, offset gravure coater, kiss coater, natural roll coater, air knife coater, roll blade coater, two-stream coater, rod coater, wire bar coater, applicator, dip coater, curtain coater, spin coater, knife coater, etc. However, the application of the color conversion composition is not limited to these.

<Light source unit>
A light source unit according to an embodiment of the present invention (hereinafter sometimes abbreviated as the light source unit of the present invention) is configured to include at least a light source and the above-described color conversion composition or color conversion member. When the light source unit of the present invention includes a color conversion composition, the arrangement of the light source and the color conversion composition is not particularly limited. The color conversion composition may be applied directly to the light source, or the color conversion composition may be applied to a substrate such as a film or glass that is separated from the light source. When the light source unit of the present invention includes a color conversion member, the arrangement of the light source and the color conversion member is not particularly limited. The light source and the color conversion member may be closely attached to each other, or a remote phosphor type in which the light source and the color conversion member are separated from each other may be used. The light source unit of the present invention may further include a color filter to enhance color purity, or an optical member such as a prism sheet, a reflective polarizing film, or a diffusion film to improve brightness and uniformity of emitted light.

One embodiment of the light source unit of the present invention includes a color conversion member (color conversion sheet) having the configuration illustrated in Figure 5 above, with the light source located below the plane of Figure 5 (below base layer 10A) and a prism sheet and reflective polarizing film stacked above the plane of Figure 5 (above base layer 10B). A diffuser plate may be provided between the light source and the color conversion member shown in Figure 5, and a reflector plate may be provided below the light source.

Another embodiment of the light source unit of the present invention is a configuration comprising a light source and a light guide plate, with a color conversion layer formed by directly applying the color conversion composition of the present invention laminated on the light output side of the light guide plate. In a light source unit having this configuration, a light diffusion layer or a wavelength selective transmission layer may further be formed on the color conversion layer.

The light source unit of the present invention is useful for various light sources such as spatial lighting and backlighting. Specifically, the light source unit of the present invention can be used for applications such as displays, lighting devices, interiors, signs, and billboards, but is particularly suitable for use in displays and lighting devices.

<Light source>
The light source provided in the light source unit of the present invention can be any light source that emits light in a wavelength range that can be absorbed by the light-emitting material used in the color-converting composition or color-converting member of the present invention. In principle, any excitation light source can be used, such as a hot cathode tube, a cold cathode tube, a fluorescent light source such as inorganic electroluminescence (EL), an organic EL element light source, a light-emitting diode (LED) light source, an incandescent light source, or sunlight. Among these, from the viewpoint of color purity, an LED or an organic EL element is preferred as the light source, and an LED is more preferred.

For example, in display and lighting applications, LEDs or organic EL elements with a maximum emission wavelength in the range of 400 nm to 500 nm are preferred light sources, as they can enhance the color purity of blue light. Furthermore, blue LEDs with a maximum emission wavelength in the range of 430 nm to 480 nm are more preferred, and blue LEDs with a maximum emission wavelength in the range of 445 nm to 470 nm are particularly preferred.

The above light source may have one emission peak or two or more emission peaks, but in order to increase color purity, it is preferable for it to have one emission peak. It is also possible to use any combination of multiple light sources with different emission peaks.

<Displays and lighting equipment>
A display according to an embodiment of the present invention includes at least a light source unit having a light source and a color-converting composition or a color-converting member as described above. For example, in a display such as a liquid crystal display, the light source unit described above is used as a backlight unit.

In addition, a lighting device according to an embodiment of the present invention includes at least a light source unit having a light source and a color conversion composition or color conversion member, as described above. For example, this lighting device is configured to emit white light by combining a blue LED light source as the light source unit with a color conversion composition or color conversion member that converts the blue light from this blue LED light source into light with a longer wavelength.

The present invention will be explained below using examples, but the present invention is not limited to the following examples. First, the evaluation methods and materials, such as luminescent materials, used in the examples and comparative examples will be explained.

<Measurement of Emission Spectrum>
In measuring the emission spectra, the fluorescent emission spectrum and phosphorescent emission spectrum of the luminescent material dissolved in a solution (hereinafter referred to as the luminescent material in a solution state), and the fluorescent emission spectrum and phosphorescent emission spectrum of the luminescent material in the binder resin contained in the color conversion member (hereinafter referred to as the luminescent material in the color conversion member) were measured.

Specifically, when measuring the fluorescence and phosphorescence emission spectra of a luminescent material in a solution state, a compound serving as the target organic luminescent material was dissolved in toluene at a concentration of 1 × ¹⁰ mol/L to prepare a sample of the compound contained in a dilute toluene solution (hereinafter referred to as a solution sample). After nitrogen bubbling through the prepared solution sample, the fluorescence and phosphorescence emission spectra of the solution sample were measured using a fluorescence spectrophotometer (Fluoromax 4, manufactured by Horiba, Ltd.). When measuring the fluorescence and phosphorescence emission spectra of a luminescent material in a color conversion member, a color conversion composition containing the target organic luminescent material compound was molded into a film to prepare a small sample. The fluorescence and phosphorescence emission spectra of the small sample were measured using a fluorescence spectrophotometer (Fluoromax 4, manufactured by Horiba, Ltd.). The fluorescence emission spectrum was measured at room temperature (300 K), and the phosphorescence emission spectrum was measured at 77 K.

<Measurement of luminescence quantum yield>
In the measurement of the luminescence quantum yield, the luminescence quantum yield of the luminescent material in a solution state and the luminescence quantum yield of the luminescent material in the color conversion member were measured.

Specifically, when measuring the luminescence quantum yield of a luminescent material in a solution state, a compound that is the target organic luminescent material was dissolved in toluene at a concentration of 1 × 10 ^-5 mol/L to prepare a solution sample, and the prepared solution sample was then subjected to nitrogen bubbling, and the luminescence quantum yield of the solution sample was measured when excited with excitation light having a wavelength of 460 nm using an absolute PL quantum yield measurement device (Quantaurus-QY, manufactured by Hamamatsu Photonics K.K.). Furthermore, when measuring the luminescence quantum yield of a luminescent material in a color conversion member, a color conversion composition containing the target organic luminescent material compound was formed into a film to prepare a small piece sample, and the luminescence quantum yield of the small piece sample was measured when excited with excitation light having a wavelength of 460 nm using an absolute PL quantum yield measurement device (Quantaurus-QY, manufactured by Hamamatsu Photonics K.K.).

<Fluorescence lifetime measurement method and reverse intersystem crossing rate constant calculation method>
In the fluorescence lifetime measurement, the fluorescence lifetime of the luminescent material in solution and that of the luminescent material in the color conversion member were measured, and in the calculation of the reverse intersystem crossing rate constant, the reverse intersystem crossing rate constants of the luminescent material in solution and that of the luminescent material in the color conversion member were calculated.

Specifically, when measuring the fluorescence lifetime of a luminescent material in solution, a compound that is the target organic luminescent material was dissolved in toluene at a concentration of 1 × ¹⁰ mol/L to prepare a solution sample, and the prepared solution sample was subjected to nitrogen bubbling. The fluorescence lifetime of the solution sample was then measured using a compact fluorescence lifetime measurement device (Quantaurus-Tau, manufactured by Hamamatsu Photonics K.K.). The fast and slow components of the fluorescence lifetime of the solution sample were observed at the maximum emission wavelength measured at an excitation wavelength of 470 nm, and the reverse intersystem crossing rate constant k _RISC for the solution sample was calculated based on the method described in Angew. Chem. Int. Ed. 2020, 59.17442. Furthermore, when measuring the fluorescence lifetime of the light-emitting material in the color conversion member, a color conversion composition containing a compound that is the target organic light-emitting material was molded into a film to prepare a small sample, and the fluorescence lifetime of the small sample was measured using a compact fluorescence lifetime measurement device (Quantaurus-Tau, manufactured by Hamamatsu Photonics K.K.). The fast and slow components of the fluorescence lifetime of the small sample were observed at the maximum emission wavelength measured at an excitation wavelength of 470 nm, and the reverse intersystem crossing rate constant k' _RISC of the small sample was calculated based on the same method as above.

<Calculation method for the activation energy of reverse intersystem crossing>
In calculating the activation energy of reverse intersystem crossing, the activation energy E _RISC of reverse intersystem crossing in the luminescent material in a solution state and the activation energy E' _RISC of reverse intersystem crossing in the luminescent material in the color conversion member were calculated.

Specifically, when calculating the reverse intersystem crossing activation energy E _RISC of a luminescent material in a solution state, the reverse intersystem crossing rate constant k _RISC was calculated by the above-mentioned method at three or more temperatures (e.g., −50°C, 0°C, and 50°C) in the temperature range of −50°C to 50°C, and then the value of lnk _RISC T ^0.5 at each temperature T was plotted using the above-mentioned formula (A-3), with lnk _RISC T ^0.5 in formula (A-3) on the vertical axis and 1/T on the horizontal axis. The slope of the approximation line based on these plotted values was then referenced to determine the target reverse intersystem crossing activation energy E _RISC . In formula (A-3), lnA is, as described above, the value determined from the intersection of the approximation line and the vertical axis at 1/T=0.

Similarly, when calculating the reverse intersystem crossing activation energy E' _RISC of the luminescent material in the color conversion member, the reverse intersystem crossing rate constant k' _RISC was calculated using the above-mentioned method at three or more temperatures (e.g., -50°C, 0°C, and 50°C) in the temperature range of -50°C to 50°C. Then, using the above-mentioned formula (A-8), the value of lnk' _RISC T' ^0.5 at each temperature T' was plotted with lnk' _RISC T' ^0.5 in formula (A-8) on the vertical axis and 1/T' on the horizontal axis. The slope of the approximation line based on these plotted values was then used to determine the target reverse intersystem crossing activation energy E' _RISC . In formula (A-8), lnA' is the value determined from the intersection of the approximation line and the vertical axis at 1/T' = 0, as described above.

<Measurement of chromaticity change>
In measuring the change in chromaticity, a light-emitting device equipped with a blue LED (manufactured by USHIO EPITEX Corporation; model number SMBB450H-1100, emission peak wavelength: 450 nm) was first turned on so that the intensity of the emitted blue light was 8000 nits. The intensity of the blue light was measured using a spectroradiometer (manufactured by Konica Minolta, Inc.; model number CS-1000).

Next, the color conversion members prepared in the examples and comparative examples described below were placed between the blue LED of the light-emitting device and the spectroradiometer. The blue light from the blue LED was color-converted by the color conversion member, and the initial chromaticity y value of the color-converted transmitted light in the xy coordinate system was measured using the spectroradiometer. The distance between the color conversion member and the blue LED was 3 cm.

Then, blue light was irradiated from the blue LED onto the color conversion element for 200 hours, and the blue light irradiated successively was color converted for 200 hours by the color conversion element, which was kept at 75°C or 30°C. The chromaticity y of the transmitted light after this 200-hour continuous color conversion was measured using the spectroradiometer, and the absolute value of the change in chromaticity y from the initial value (Δy (75°C), Δy (30°C)) was calculated.

<Light durability evaluation>
In the light durability evaluation, in each of the examples and comparative examples described below, a light emitting device equipped with the prepared color conversion member and a blue LED (manufactured by USHIO EPITEX Corporation; model number SMBB450H-1100, emission peak wavelength: 450 nm) was subjected to a current of 500 mA to light up the blue LED, and the initial emission peak intensity was measured using a spectroradiometer (CS-1000, manufactured by Konica Minolta). The distance between the color conversion member and the blue LED in this light emitting device was 3 cm. Thereafter, the light from the blue LED was continuously irradiated in an environment of 75°C, and the light durability of the color conversion member was evaluated by observing the time until the emission peak intensity decreased by 5%.

<Organic light-emitting materials>
In the following examples and comparative examples, compounds D-1 to D-3 were used as the organic light-emitting material contained in the color conversion member. Compounds D-1 to D-3 are the compounds shown below.

<Scattering agent>
In the following examples and comparative examples, titanium dioxide particles "JR-301" (manufactured by Teika Co., Ltd.) were used as the scattering agent.

Example 1
In Example 1, first, PMMA resin "BR-85" (manufactured by Mitsubishi Chemical Corporation) was used as the binder resin, and 0.10 parts by weight of compound D-1 as the luminescent material, 3 parts by weight of JR-301 as a scattering agent, and 300 parts by weight of ethyl acetate as a solvent were mixed with 100 parts by weight of this binder resin. This mixture was then stirred and degassed for 20 minutes at 1000 rpm using a planetary stirring and degassing device "Mazerustar" (registered trademark) KK-400 (manufactured by Kurabo Industries, Ltd.). This yielded a resin composition for producing a color conversion layer (the color conversion composition of Example 1).

Next, the resin composition for producing the color conversion layer obtained above was applied to "Cerapeel" BLK (manufactured by Toray Advanced Film Co., Ltd.) using a film applicator, and then heated and dried at 120°C for 20 minutes. This formed a color conversion layer with an average film thickness of 20 μm.

Next, a hydrochloric acid solution prepared by mixing 0.1N hydrochloric acid (4g) and water (5g) was slowly added dropwise to a mixture of tetraethyl orthosilicate (1.2g), 2-propanol (0.5g), and methanol (0.5g). Then, a polyvinyl alcohol resin (0.4g) with a saponification degree of 98 mol% or higher was mixed into this mixture and stirred. This yielded a resin solution for producing an oxygen barrier layer.

This resin liquid for producing the oxygen barrier layer was applied by bar coating to an alumina-deposited polyethylene terephthalate film "Barrierox" (registered trademark) 1011HG (manufactured by Toray Industries, Inc., thickness 12 μm), and then dried at 150°C for 1 minute. This formed a coating layer of the resin liquid. Furthermore, a coating layer with an average thickness of approximately 1 μm was formed on this coating layer, thereby producing an oxygen barrier laminate film, an example of a barrier layer. In Example 1, two sheets of this oxygen barrier laminate film were prepared.

Next, a thermosetting adhesive layer was formed by coating on the polyvinyl alcohol resin layer of one of the oxygen barrier laminate films, and the above-mentioned color conversion layer was laminated on top of that. The above-mentioned "Therapeel" BLK was then peeled off from the color conversion layer.

Finally, a thermosetting adhesive layer was formed by coating on the polyvinyl alcohol resin layer of the other oxygen barrier laminate film, and the resulting thermosetting adhesive layer was laminated on top of the color conversion layer after peeling off the "Cerapeel" BLK. This produced a sheet-like color conversion member (for example, the color conversion sheet illustrated in Figure 3). The average film thickness of all thermosetting adhesive layers contained in this color conversion member was 0.50 μm. Note that the thermosetting adhesive layer is not shown in Figure 3.

Compound D-1, the luminescent material of Example 1, was evaluated and showed high color purity green fluorescent light emission in a dilute toluene solution, with a peak wavelength of 518 nm and a half-width of 17 nm. Furthermore, evaluation of Compound D-1 in a dilute toluene solution (luminescent material in solution state) revealed that the E _{F -EP} value was 0.018 eV, the E _RISC value was 0.018 eV/mol, and the k _RISC (30°C) value was 0.70 × 10 ^-5 .

In Example 1, as described above, a sheet-like color conversion member containing Compound D-1 as the light-emitting material was prepared and evaluated. As a result, Compound D-1 exhibited high-color-purity green fluorescent light emission in the prepared sheet-like color conversion member, with a peak wavelength of 518 nm and a half-width of 23 nm. Furthermore, evaluation of Compound D-1 in the color conversion member revealed that the E' _F -E' _P value was 0.018 eV, the E' _RISC value was 0.018 eV/mol, and the k' _RISC (30°C) value was 1.3 × 10 ^-5 . Furthermore, using the color conversion member of Example 1, the color conversion was performed for 200 hours continuously by irradiating blue light as described above with continuous light in an environment maintained at 30°C, and the Δy (30°C) was measured when the color conversion was performed for 200 hours continuously by irradiating blue light as described above with continuous light in an environment maintained at 70°C. As a result, the value of Δy(75° C.)/Δy(30° C.) was 0.60.

Furthermore, when the color conversion member of Example 1 was continuously irradiated with light from a blue LED in an environment of 50°C, the time until the emission peak intensity decreased by 5% (light durability) was approximately 500 hours. Example 1 showed approximately twice the improvement in light durability compared to Comparative Example 1 described below. The luminescent material and evaluation results of Example 1 are as shown in Table 1 described below. In Table 1, the "Dilute Solution" column shows the evaluation results of the luminescent material in solution state. The "Film" column shows the evaluation results of the luminescent material in the color conversion member.

Comparative Example 1
In Comparative Example 1, a sheet-like color conversion member was produced and evaluated in the same manner as in Example 1, except that the luminescent material was changed to Compound D-2 and the amount of the luminescent material mixed was adjusted to be the same as that of Compound D-1 in Example 1. The luminescent material and evaluation results of Comparative Example 1 are shown in Table 1.

Comparative Example 2
In Comparative Example 2, a sheet-like color conversion member was produced and evaluated in the same manner as in Example 1, except that the luminescent material was changed to Compound D-3 and the amount of the luminescent material mixed was adjusted to be the same as that of Compound D-1 in Example 1. As a result of the evaluation, Compound D-3 in Comparative Example 2 did not exhibit phosphorescence either in the solution state or in the color conversion member. The luminescent material and evaluation results of Comparative Example 2 are as shown in Table 1.

As described above, the color-converting composition and color-converting member according to the present invention, as well as the light source unit, display, and lighting device containing the same, are suitable for achieving both high color purity and high durability.

1A, 1B, 1C, 1D, 1E, 1F Color conversion member 10, 10A, 10B Base layer 11, 11A, 11B Color conversion layer 12A, 12B Barrier layer 13 Intermediate layer

Claims (15)

A color-converting composition comprising at least one organic light-emitting material and a binder resin,
Satisfies the following formula (A-1):
A color-changing composition comprising:
(In formula (A-1), E _F represents energy at a peak wavelength of a fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents energy at a peak wavelength of a phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution.) Satisfies the following formula (A-2):
2. The color-changing composition of claim 1.
(In formula (A-2), E _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in a dilute toluene solution in a temperature range of −50° C. or more and 50° C. or less. _{E RISC} is a value that can be calculated using the following formula (A-3).)
(In formula (A-3), ln represents the natural logarithm. _{k RISC} represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at each temperature. T represents the temperature [K] of the dilute toluene solution. _kB represents Boltzmann's constant. E _RISC in formula (A-2) can be determined by first determining the reverse intersystem crossing rate constant k _RISC at each temperature T, and then using formula (A-3), plotting the values of lnk _RISC T ^0.5 at each temperature T with lnk _RISC T ^0.5 as the vertical axis and 1/T as the horizontal axis, and referring to the slope of an approximation line based on the plotted values of lnk _RISC T ^0.5 . lnA can be determined from the intersection of the approximation line and the vertical axis at 1/T=0.) Satisfies the following formula (A-4):
2. The color-changing composition of claim 1.
(In formula (A-4), k _RISC (30° C.) represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in a dilute toluene solution at 30° C.) Satisfies the following formula (A-5):
2. The color-changing composition of claim 1.
(In formula (A-5), Δy is the absolute value of the amount of change in chromaticity y from the initial value in the xy coordinates of the color-converted transmitted light when continuous light irradiation is performed for 200 hours using light from a blue LED having a peak wavelength in the range of 450 nm±3 nm and an intensity of 8000 nits. Δy(75°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 75°C. Δy(30°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 30°C.) the peak wavelength of the fluorescence emission spectrum of the at least one organic light-emitting material in a dilute toluene solution is in a wavelength range of 500 nm or more;
2. The color-changing composition of claim 1. A color conversion member comprising at least one organic light-emitting material and a binder resin,
Satisfies the following formula (A-1):
A color conversion member characterized by:
(In formula (A-1), E _F represents energy at a peak wavelength of a fluorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution. E _P represents energy at a peak wavelength of a phosphorescent emission spectrum of the at least one organic light-emitting material in a dilute toluene solution.) Satisfies the following formula (A-6):
The color conversion member according to claim 6 .
(In formula (A-6), _E'F represents the energy at the peak wavelength of the fluorescent emission spectrum of the color conversion member. _E'P represents the energy at the peak wavelength of the phosphorescent emission spectrum of the color conversion member.) Satisfies the following formula (A-7):
The color conversion member according to claim 6 .
(In formula (A-7), E' _RISC represents the activation energy of reverse intersystem crossing of the at least one organic light-emitting material contained in the color conversion member in a temperature range of -50°C or more and 50°C or less. E' _RISC is a value that can be calculated using the following formula (A-8).)
(In formula (A-8), ln represents the natural logarithm. k' _RISC represents the reverse intersystem crossing rate constant of the at least one organic light-emitting material contained in the color conversion member at each temperature. T' represents the temperature [K] of the color conversion member. _kB represents the Boltzmann constant. E' _RISC in formula (A-7) can be determined by first determining the reverse intersystem crossing rate constant k' _RISC at each temperature T', and then using formula (A-8), plotting the values of lnk' _RISC T' ^0.5 at each temperature T' with lnk' _RISC T' ^0.5 on the vertical axis and 1/T' on the horizontal axis, and referring to the slope of the approximation line based on the plotted values of lnk' _RISC T' ^0.5 . lnA' can be determined from the intersection of the approximation line and the vertical axis at 1/T' = 0.) Satisfies the following formula (A-9):
The color conversion member according to claim 6 .
(In formula (A-9), k' _RISC (30°C) represents the rate constant of reverse intersystem crossing of the at least one organic light-emitting material contained in the color conversion member at 30°C.) Satisfies the following formula (A-5):
The color conversion member according to claim 6 .
(In formula (A-5), Δy is the absolute value of the amount of change in chromaticity y from the initial value in the xy coordinates of the color-converted transmitted light when continuous light irradiation is performed for 200 hours using light from a blue LED having a peak wavelength in the range of 450 nm±3 nm and an intensity of 8000 nits. Δy(75°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 75°C. Δy(30°C) represents the Δy when the continuous light irradiation is performed while keeping the temperature at 30°C.) the peak wavelength of the fluorescence emission spectrum of the at least one organic light-emitting material in a dilute toluene solution is in a wavelength range of 500 nm or more;
The color conversion member according to claim 6 . having an oxygen barrier layer,
The color conversion member according to claim 6 . A light source and
The color conversion member according to claim 6 ;
A light source unit comprising: A light source unit according to claim 13,
A display characterized by: A light source unit according to claim 13,
A lighting device characterized by: