Color conversion sheet, and light source unit, display, and illumination device including same

Abstract

Provided are: a color conversion sheet that is used in a display, an illumination device, or the like, and that has high in-plane uniformity and durability; and a light source unit, a display, and an illumination device that include the color conversion sheet. A color conversion sheet for converting incident light into light having a wavelength different from that of the incident light, the color conversion sheet containing at least a color conversion layer (A), a color conversion layer (B), a resin layer, and a base material, the color conversion layer (A) containing a light-emitting material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm, and the resin layer (B) containing a light-emitting material (b) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm. The color conversion layer (B) contains a light-emitting material (b) that emits light having a peak wavelength observed in a region of 580-750 nm inclusive, the haze value of the color conversion sheet is 20-90% inclusive, and when the refractive index of the color conversion layer (A) is nA1, the refractive index of the color conversion layer (B) is nA2, and the refractive index of the resin layer is nB, nA1 > nB and nA2 > nB are satisfied.

Description

[0001] This application is a divisional application of the patent application with the application number 202180051020.X and the invention title "Color Conversion Sheet and Light Source Unit, Display, and Lighting Device Containing the Same" filed on September 14, 2021. Technical Field

[0002] The present invention relates to a color conversion sheet and a light source unit, a display, and a lighting device containing the same. Background Art

[0003] There is an active research on applying multicolorization technology using a color conversion method to liquid crystal displays, organic electroluminescence (EL) displays, lighting, etc. The so-called color conversion means converting the light emitted from a light emitter into light with a longer wavelength, for example, converting blue light into green light or red light.

[0004] By forming a composition having the color conversion function into a sheet and combining it with a blue light source, it is possible to extract light of the three primary colors, blue, green, and red, from the blue light source, and thus white light can be obtained. A white light source formed by combining such a blue light source and a sheet having a color conversion function (hereinafter referred to as a "color conversion sheet") is used as a light source unit, and combined with a liquid crystal driving part and a color filter, whereby a full-color display can be manufactured. In addition, the white light source can also be directly applied to light emitting diode (LED) lighting, etc.

[0005] As a problem of a liquid crystal display using a color conversion method, it can be cited that there is a deviation in the color sense of the light emitted from the light source in the light emitting region of the backlight device. As a method for solving the above problem, a technique of increasing the content of the color conversion material per unit area in a part of the color conversion sheet located at the peripheral part of the display has also been proposed (for example, refer to Patent Document 1).

[0006] In addition, in order to prevent the deterioration of the organic light emitting material and improve the durability, a technique of adding a light stabilizer has also been disclosed (for example, refer to Patent Document 2).

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-195583

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-241160 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] However, in Patent Document 1, since the content of the color-changing material is increased, the brightness decreases due to the aggregation of the phosphor, and the technology for maintaining sufficient durability is insufficient. In addition, in Patent Document 2, sufficient in-plane uniformity cannot be ensured, and the balance between in-plane uniformity and durability is insufficient.

[0013] The problem to be solved by the present invention is to provide a color-changing sheet having high in-plane uniformity and durability in a color-changing sheet used for a display, a lighting device, or the like.

[0014] Technical Means for Solving the Problem

[0015] To solve the above problems and achieve the object, the color-changing sheet of the present invention is a color-changing sheet that converts incident light into light having a wavelength different from that of the incident light. The color-changing sheet contains at least a color-changing layer (A), a color-changing layer (B), a resin layer, and a substrate. The color-changing layer (A) contains a light-emitting material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm. The color-changing layer (B) contains a light-emitting material (b) that emits light having a peak wavelength observed in a region of 580 nm or more and 750 nm or less. The haze value of the color-changing sheet is 20% or more and 90% or less. When the refractive index of the color-changing layer (A) is set to n A1 , the refractive index of the color-changing layer (B) is set to n A2 , and the refractive index of the resin layer is set to n B , n A1 , n A2 , and n B satisfy the following relationship (1) or (2):

[0016] (1) n A1 > n B and n A2 > n B

[0017] (2) n A1 < n B and n A2 < n B .

[0018] In addition, another embodiment of the present invention is a color-changing sheet that converts incident light into light having a wavelength different from that of the incident light. The color-changing sheet contains at least a color-changing layer (A), a color-changing layer (B), a resin layer, and a substrate,

[0019] The color conversion layer (A) contains a luminescent material (a) that emits light with a peak wavelength observed in the region of 500 nm or more and less than 580 nm, the color conversion layer (B) contains a luminescent material (b) that emits light with a peak wavelength observed in the region of 580 nm or more and 750 nm or less, the haze value of the color conversion sheet is 20% or more and 90% or less, and scattering particles are contained in either or both of the color conversion layer (A) and the color conversion layer (B). When the haze of the color conversion layer (A) is set to H A and the haze of the color conversion layer (B) is set to H B , |H A -H B |≥20%.

[0020] In addition, another embodiment of the present invention is a color conversion sheet that converts incident light into light having a wavelength different from that of the incident light. The color conversion sheet at least sequentially includes a color conversion layer, a resin layer, and a substrate.

[0021] The color conversion layer contains a luminescent material (a) that emits light with a peak wavelength observed in the region of 500 nm or more and less than 580 nm and a luminescent material (b) that emits light with a peak wavelength observed in the region of 580 nm or more and 750 nm or less, and the haze value of the color conversion sheet is 20% or more and 90% or less.

[0022] When the refractive index of the color conversion layer is set to n A , the refractive index of the resin layer is set to n B , and the refractive index of the substrate is set to n C , n A >n B and n B <n C .

[0023] Effects of the Invention

[0024] The color conversion sheet of the present invention exhibits the effects of high in-plane uniformity and durability. Since the light source unit, display, and lighting device of the present invention use such a color conversion sheet, they exhibit the effects of high in-plane uniformity and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic cross-sectional view showing an example of the color conversion sheet of the present invention.

[0026] Figure 2 It is a schematic cross-sectional view showing an example of the color conversion sheet of the present invention.

[0027] Figure 3It is a schematic cross-sectional view showing an example of the color conversion sheet of the present invention.

[0028] Figure 4 It is a schematic cross-sectional view showing an example of the color conversion sheet of the present invention.

[0029] Figure 5 It is a schematic cross-sectional view showing an example of the light source unit of the present invention.

[0030] Explanation of symbols

[0031] 1: Substrate layer

[0032] 2: Color conversion layer (B)

[0033] 3: Resin layer

[0034] 4: Color conversion layer (A)

[0035] 5: Color conversion sheet

[0036] 6: Barrier layer

[0037] 7: Color conversion layer

[0038] 8: Substrate

[0039] 9: Reflective layer

[0040] 10: Light source

[0041] 11: Diffusion plate

[0042] 12: Prismatic sheet

[0043] 13: Polarization reflective film

[0044] 14: Light source unit Detailed implementation manners

[0045] Hereinafter, the implementation manners of the present invention will be specifically described. However, the present invention is not limited to the following implementation manners and can be implemented with various modifications according to the purpose or use.

[0046] The color conversion sheet of the present invention is a color conversion sheet that converts incident light from a light source or the like into light having a wavelength different from that of the incident light. The color conversion sheet contains at least a color conversion layer (A), a color conversion layer (B), a resin layer, and a substrate. The color conversion layer (A) is a layer containing a luminescent material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm, and the color conversion layer (B) is a layer containing a luminescent material (b) that emits light having a peak wavelength observed in a region of 580 nm or more and 750 nm or less.

[0047] The peak wavelength of the luminescence of a luminescent material (such as the luminescent material (a) and the luminescent material (b), etc.) can be confirmed by measuring the fluorescence spectrum of its solution. The solvent used for the fluorescence spectrum measurement is not particularly limited, and solvents such as toluene, dichloromethane, and tetrahydrofuran can be preferably used. As long as the solubility of the luminescent material is not a problem, it is more preferable to use toluene as the solvent.

[0048] Hereinafter, the luminescence with a peak wavelength observed in the region of 500 nm or more and less than 580 nm is referred to as "green luminescence". The luminescence with a peak wavelength observed in the region of 580 nm or more and 750 nm or less is referred to as "red luminescence".

[0049] In order to cause a luminescent material to emit light, the light irradiated onto the luminescent material is called excitation light. Generally, the greater the energy of the excitation light, the more likely it is to cause decomposition of the material. The energy of the excitation light in the range of 400 nm or more and 500 nm or less is small and does not cause decomposition of the luminescent material in the color conversion composition, so luminescence with good color purity can be obtained. As the incident light from a light source or the like that can be incident on the color conversion sheet, excitation light can be used.

[0050] A part of the excitation light in the range of 400 nm or more and 500 nm or less (hereinafter referred to as "blue light") passes through the color conversion sheet without being converted into light of a different wavelength, so it can be used as blue luminescence itself. In addition, the color conversion sheet of the present invention contains a luminescent material (a) that exhibits green luminescence and a luminescent material (b) that exhibits red luminescence. Therefore, when a white light source is formed by combining a blue LED light source having a sharp-shaped luminescence peak in the color conversion sheet of the present invention, white light with a sharp-shaped luminescence spectrum and good color purity can be obtained in each of the colors of blue, green, and red. As a result, in particular, a display using the white light source can efficiently form a more vivid and larger color gamut. In addition, in a lighting device, compared with a white LED formed by combining a blue LED and a yellow phosphor, which is currently the mainstream, the luminescence characteristics in particular in the green region and the red region are improved, so a preferable white light source with improved color rendering property can be obtained.

[0051] In order to expand the color gamut of a display and improve color reproducibility, it is preferable that the overlap of the luminescence spectra of each of the colors of blue, green, and red is small.

[0052] For example, in the case where blue light in the wavelength range of 400 nm or more and 500 nm or less is used as the excitation light, by using a luminescent material (a) that exhibits luminescence with a peak wavelength observed in the region of 500 nm or more and converting the blue light into green light, the overlap of the emission spectra of the excitation light and the green light becomes smaller, and the color reproducibility is improved. On the basis of further enhancing the above effect, the lower limit value of the peak wavelength of the luminescent material (a) is more preferably 510 nm or more, further preferably 515 nm or more, and particularly preferably 520 nm or more.

[0053] In addition, in order to reduce the overlap of the emission spectra of the green light and the red light, it is preferable to use a luminescent material (a) that exhibits luminescence with a peak wavelength observed in the region of 580 nm or less. On the basis of further enhancing the above effect, the upper limit value of the peak wavelength of the luminescent material (a) is more preferably 550 nm or less, further preferably 540 nm or less, and particularly preferably 535 nm or less.

[0054] Furthermore, by using a luminescent material (a) that exhibits luminescence with a peak wavelength observed in the region of 500 nm or more and less than 580 nm for green luminescence, and a luminescent material (b) that exhibits luminescence with a peak wavelength observed in the region of 580 nm or more for red luminescence, the overlap of the emission spectra of the green light and the red light becomes smaller, and the color reproducibility is improved. On the basis of further enhancing the above effect, the lower limit value of the peak wavelength of the luminescent material (b) is more preferably 610 nm or more, further preferably 620 nm or more, and particularly preferably 630 nm or more.

[0055] The upper limit of the peak wavelength of the luminescent material (b) only needs to be near the upper bound of the visible light range, that is, 750 nm or less. In the case where it is 700 nm or less, the visual acuity becomes larger, so it is more preferable. On the basis of further enhancing the above effect, the upper limit value of the peak wavelength of the luminescent material (b) is further preferably 680 nm or less, and particularly preferably 660 nm or less.

[0056] That is, in the case where blue light in the wavelength range of 400 nm or more and 500 nm or less is used as the excitation light, the peak wavelength of the luminescent material (a) is preferably observed in the region of 500 nm or more and less than 580 nm, more preferably 510 nm or more and 550 nm or less, further preferably 515 nm or more and 540 nm or less, and particularly preferably 520 nm or more and 535 nm or less. In addition, the peak wavelength of the luminescent material (b) is preferably observed in the region of 580 nm or more and 750 nm or less, more preferably 610 nm or more and 700 nm or less, further preferably 620 nm or more and 680 nm or less, and particularly preferably 630 nm or more and 660 nm or less.

[0057] In order to reduce the overlap of the emission spectra and improve color purity and color reproducibility, it is preferable that the half-value widths of the emission spectra of each of the blue, green, and red colors are small. In particular, small half-value widths of the emission spectra of green light and red light are effective for improving color purity or color reproducibility.

[0058] As described above, the color conversion sheet of the present invention has at least two color conversion layers including a color conversion layer (A) containing a luminescent material (a) and a color conversion layer (B) containing a luminescent material (b). By containing the luminescent material (a) and the luminescent material (b) in different layers, the interaction between the materials is suppressed, and compared with the case where the luminescent material (a) and the luminescent material (b) are dispersed in the same layer, emission with higher color purity can be exhibited, and thus it is preferable. In addition, since the luminescent material (a) and the luminescent material (b) emit light independently in each layer, it becomes easy to adjust the emission peak wavelength or emission intensity of green and red.

[0059] As a representative structural example of the color conversion sheet of the present invention, for example, Figure 1 . Figure 1 is a schematic cross-sectional view showing an example of the color conversion sheet of the present invention. Figure 1 The color conversion sheet 5 shown includes a substrate layer 1, and a color conversion layer (B) 2, a resin layer 3, and a color conversion layer (A) 4 are sequentially provided on the substrate layer 1. In addition, Figure 2 Another example of the color conversion sheet of the present invention is shown in. In Figure 2 the color conversion sheet shown, a structure may be provided in which a substrate layer 1 is further disposed on the color conversion layer (A) 4, and the color conversion layer (B) 2, the resin layer 3, and the color conversion layer (A) 4 are sandwiched by the substrate layer 1.

[0060] Furthermore, the above structural example is for illustration, and the specific structure of the color conversion sheet of the present embodiment is not limited thereto, and a structure obtained by appropriately changing matters derived from the following description is also included in the scope of the present invention.

[0061] <Haze value of the color conversion sheet>

[0062] In the present invention, the haze value of the color conversion sheet is 20% or more and 90% or less. By being within the above range, the scattering of light in the color conversion layer increases, so the light conversion efficiency of the luminescent material is improved, and the in-plane uniformity and durability of the color conversion sheet can be taken into account. The haze value is more preferably 50% or more and 75% or less. The haze value can be measured according to American Society for Testing Material (ASTM) D 1003 (2013).

[0063] As a method for making the haze value of the color conversion sheet of the present invention fall within the above range, there is no particular limitation, and examples thereof include a method of containing scattering particles in the color conversion layer, a method of separately providing a light scattering layer from the color conversion layer, and a method of increasing the surface roughness of the base material constituting the color conversion sheet. Among these, a method of containing scattering particles in the color conversion layer is more preferable.

[0064] As an embodiment of the color conversion sheet of the present invention when scattering particles are contained in either or both of the color conversion layer (A) and the color conversion layer (B), when the haze of the color conversion layer (A) is set to H A and the haze of the color conversion layer (B) is set to H B it is preferable that |H A - H B | ≧ 20%. The absolute value of the haze difference between the color conversion layer (A) and the color conversion layer (B) has a great influence on the color gamut and brightness of the resulting display. By making the difference between H A and H B fall within the above range, a color conversion sheet with a high color gamut and high brightness as described later can be obtained.

[0065] <Scattering Particles>

[0066] As the scattering particles for controlling the haze, particles of organic substances and / or inorganic substances can be cited.

[0067] Specifically, examples include particles containing glass, titanium dioxide, silicon dioxide, aluminum oxide, silicone resin, zirconium oxide, cerium oxide, aluminum nitride, silicon carbide, silicon nitride, barium titanate, acrylic resin, etc. These can be used alone or in combination of two or more. From the viewpoint of easy availability, particles selected from silica particles, alumina particles, titanium dioxide particles, zirconium oxide particles, acrylic resin particles, silicone resin particles, etc. are preferable. From the viewpoint of dispersibility in the binder resin in the color conversion layer, titanium dioxide particles are more preferable.

[0068] In addition, from the viewpoint of improving brightness, the scattering particles preferably contain particles selected from alumina particles, silica particles, and silicone resin particles. When the refractive index of the scattering particles contained in the color conversion layer (A) is set to n A1 and the refractive index of the color conversion layer (B) is set to n A2 , when the refractive index of the scattering particles contained in the color conversion layer (A) is set to n D1 and the refractive index of the scattering particles contained in the color conversion layer (B) is set to n D2 it is preferable that n A1 , n A2 , n D1 and n D2 satisfy 0.03 ≦ |nA1 -n D1 |≤0.3 and / or 0.03≤|n A2 -n D2 |≤0.3. By making n A1 and n D1 the difference of and / or n A2 and n D2 the difference of is within the above range, high haze and high transmittance can be taken into account. Furthermore, when scattering particles are contained in both the color conversion layer (A) and the color conversion layer (B), it is preferably satisfied that 0.03≤|n A1 -n D1 |≤0.3 and 0.03≤|n A2 -n D2 |≤0.3.

[0069] Regarding the average particle diameter of the scattering particles, as long as the haze value is within the above range, there is no particular limitation, and it is preferably 100 nm to 5000 nm, and more preferably 100 nm to 500 nm. By using scattering particles with an average particle diameter within the above range, the dispersibility in the binder resin becomes good, and the light scattering efficiency of the luminescent material is improved.

[0070] In addition, in the present invention, it is preferable that either or both of the color conversion layer (A) and the color conversion layer (B) contain scattering particles. The scattering particles are preferably contained in a state shifted to either the color conversion layer (A) or the color conversion layer (B). By the color conversion layer (A) containing scattering particles, the luminous efficiency of the (A) layer is improved, and the peak wavelength is shifted to a shorter wavelength, whereby a color conversion sheet with a larger color gamut can be obtained. In addition, by the color conversion layer (B) containing scattering particles, the color conversion efficiency of the (B) layer is improved, self-absorption is suppressed, and thus the peak wavelength is shifted to a shorter wavelength. After the peak wavelength of the color conversion layer (B) is shifted to a shorter wavelength, it can be closer to the peak of visual acuity, and a color conversion sheet with higher brightness can be obtained. Therefore, from the viewpoint of a high color gamut, it is preferable that the content of the scattering particles in the color conversion layer (A) is greater than the content of the scattering particles in the color conversion layer (B), and most preferably only the color conversion layer (A) contains scattering particles. On the other hand, from the viewpoint of high brightness, it is preferable that the content of the scattering particles in the color conversion layer (B) is greater than the content of the scattering particles in the color conversion layer (A), and most preferably only the color conversion layer (B) contains scattering particles.

[0071] When using a pyrromethene derivative or a compound with a small Stokes shift represented by the general formula (6) or the general formula (7) described later as the luminescent material contained in the color conversion layer, since the self-absorption becomes stronger, the effects in terms of high brightness and high color gamut caused by the shift of the scattering particles are significantly manifested.

[0072] <Resin layer>

[0073] The color-changing sheet of the present invention has a resin layer. The resin layer is preferably present between the color-changing layer (A) and the color-changing layer (B). When the refractive index of the color-changing layer (A) is set to n A1 , the refractive index of the color-changing layer (B) is set to n A2 , and the refractive index of the resin layer is set to n B , n A1 , n A2 and n B satisfy the following relationship (1) or (2):

[0074] (1) n A1 > n B and n A2 > n B

[0075] (2) n A1 < n B and n A2 < n B .

[0076] The resin layer that satisfies the relationship of (1) is called a low-refractive-index layer, and the resin layer that satisfies the relationship of (2) is called a high-refractive-index layer. Since the resin layer has a refractive index different from that of the color-changing layer, light is reflected at the interface between each color-changing layer and the resin layer, so the color-changing efficiency can be improved. In addition, when the resin layer has a lower refractive index than the color-changing layer, more light can be reflected compared with the case where the resin layer is a high-refractive-index layer, so light leakage to the outside can be suppressed, and thus it is more preferable.

[0077] <Low-refractive-index layer>

[0078] As described above, one embodiment of the color-changing sheet of the present invention is a color-changing sheet having a low-refractive-index layer as the resin layer. The low-refractive-index layer is preferably present between the color-changing layer (A) and the color-changing layer (B). When the refractive index of the color-changing layer (A) is set to n A1 , the refractive index of the color-changing layer (B) is set to n A2 , and the refractive index of the low-refractive-index layer is set to n B , it is required that n A1 > n B and n A2 > n B . By having a low-refractive-index layer, light is reflected at the interface between each color-changing layer and the low-refractive-index layer, so light leakage to the outside of each layer can be suppressed, and thus the color-changing efficiency can be further improved, and good durability can be obtained. Furthermore, when the refractive index of the substrate is set to n C , it is preferably n B < n CIn addition, in order to obtain stable color conversion efficiency, the difference in refractive index between the color conversion layer and the low refractive index layer is more preferably such that 0.15 ≧ n A1 - n B ≧ 0.05 and 0.15 ≧ n A2 - n B ≧ 0.05.

[0079] As the material of the low refractive index layer, if it is a resin having a refractive index satisfying n A1 > n B and n A2 > n B there is no particular limitation. Specifically, examples include photocurable resist materials having reactive vinyl groups such as acrylic acid, methacrylic acid, polyvinyl cinnamate, and cyclo rubber; epoxy resins, silicone resins (including organopolysiloxane hardeners (crosslinked products) such as silicone rubber and silicone gel), urea resins, fluororesins, polycarbonate resins, acrylic resins, urethane resins, melamine resins, polyethylene resins, polyamide resins, phenol resins, polyvinyl alcohol resins, polyvinyl butyral resins, cellulose resins, aliphatic ester resins, aromatic ester resins, aliphatic polyolefin resins, aromatic polyolefin resins, and other well-known materials. Among them, silicone resin or fluororesin as a resin having a small refractive index is preferred, and from the viewpoint of improving the durability of the color conversion sheet, silicone resin is more preferred. By using silicone resin for the resin layer, diffusion of the luminescent material (a) and the luminescent material (b) into the resin layer can be prevented, and a color conversion sheet with a small chromaticity change can be obtained even after long-term use. As an example of the silicone resin, KR-114B manufactured by Shin-Etsu Chemical Co., Ltd. can be mentioned, but it is not limited thereto.

[0080] In addition, the low refractive index layer is preferably directly adjacent in the order of the color conversion layer (A), the low refractive index layer, and the color conversion layer (B). By directly adjacently arranging each layer, the color conversion efficiency of the color conversion layer (A) and the color conversion layer (B) can be significantly improved respectively.

[0081] <High refractive index layer>

[0082] As described above, one embodiment of the color conversion sheet of the present invention is a color conversion sheet having a high refractive index layer as a resin layer. The high refractive index layer is preferably present between the color conversion layer (A) and the color conversion layer (B). When the refractive index of the color conversion layer (A) is set to n A1 , the refractive index of the color conversion layer (B) is set to n A2 , and the refractive index of the high refractive index layer is set to n B , it is necessary that n A1 < n B and n A2 < n B. By having a high refractive index layer, light is reflected at the interface between each color conversion layer and the high refractive index layer. Therefore, similar to the case of having a low refractive index layer, light leakage to the outside of each layer can be suppressed, and thus the color conversion efficiency can be further improved, and good durability can be obtained. In addition, in order to obtain a stable color conversion efficiency, the difference in refractive index between the color conversion layer and the high refractive index layer is more preferably such that 0.15 ≧ n B -n A1 ≧ 0.05 and 0.15 ≧ n B -n A2 ≧ 0.05.

[0083] As the material of the high refractive index layer, if it is a resin whose refractive index satisfies n A1 < n B and n A2 < n B , there is no particular limitation, and the same material as that of the low refractive index layer can be used. Among them, from the viewpoints of heat resistance and durability, an ester resin can be preferably used. As an example of the ester resin, "Vylon" (registered trademark) 270 manufactured by Toyobo Co., Ltd. can be cited.

[0084] In addition, the high refractive index layer is preferably directly adjacent in the order of the color conversion layer (A), the high refractive index layer, and the color conversion layer (B). By directly adjacently arranging each layer, the color conversion efficiency of the color conversion layer (A) and the color conversion layer (B) can be significantly improved respectively.

[0085] <Luminescent material>

[0086] The color conversion sheet of the present invention contains a luminescent material. The luminescent material in the present invention refers to a material that emits light with a wavelength different from that of the excitation light when irradiated with the excitation light. The color conversion layer (A) and the color conversion layer (B) may each contain one luminescent material or may contain two or more.

[0087] The color conversion layer (A) and the color conversion layer (B) may also each contain multiple layers in the color conversion sheet of the present invention. In such a case, the composition or form of each layer of the multiple color conversion layers (A) may be the same or different. Similarly, the composition or form of each layer of the multiple color conversion layers (B) may be the same or different.

[0088] In order to achieve high-efficiency color conversion, it is preferable to contain a material showing high quantum yield luminescence characteristics in the color conversion layer. As the luminescent material, known luminescent materials such as inorganic phosphors, fluorescent pigments, fluorescent dyes, and quantum dots can be cited. Furthermore, from the viewpoint of high luminescence characteristics, it is preferable to contain an organic luminescent material in at least one of the color conversion layer (A) and the color conversion layer (B).

[0089] Since organic light-emitting materials can efficiently absorb the light emission of a light source, high efficiency can be achieved when used in a color conversion layer. Examples of organic light-emitting materials include: naphthalene, anthracene, phenanthrene, pyrene, compounds or their derivatives having a condensed aryl ring such as tetracene, triphenylene, perylene, fluoranthene, fluorene, indene;

[0090] compounds or their derivatives 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, pyrrolopyridine;

[0091] borane derivatives;

[0092] stilbene derivatives such as 1,4-distyrylbenezene, 4,4'-bis(2-(4-diphenylaminophenyl)vinyl)biphenyl, 4,4'-bis(N-(styryl-4-yl)-N-phenylamino)stilbene;

[0093] aromatic acetylene derivatives, tetraphenylbutadiene derivatives, aldazine derivatives, pyrromethene derivatives, diketopyrrolo[3,4-c]pyrrole derivatives;

[0094] coumarin derivatives such as coumarin 6, coumarin 7, coumarin 153;

[0095] azole derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, triazole and their metal complexes;

[0096] cyanine compounds such as indocyanine green;

[0097] xanthene compounds or thioxanthene compounds such as fluorescein eosin rhodamine;

[0098] polyphenylene compounds, naphthalenediimide derivatives, phthalocyanine derivatives and their metal complexes, porphyrin derivatives and their metal complexes;

[0099] oxazine compounds such as nile red or nile blue;

[0100] helicene compounds;

[0101] Aromatic amine derivatives such as N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine; and

[0102] Organometallic complex compounds such as iridium (Ir), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt), osmium (Os), and rhenium (Re);

[0103] etc. are preferred as organic light-emitting materials, but are not limited to these.

[0104] The organic light-emitting material can be a fluorescent light-emitting material or a phosphorescent light-emitting material. In order to achieve high color purity, a fluorescent light-emitting material is preferred.

[0105] Among these, in terms of high thermal stability and light stability, compounds or their derivatives having a condensed aryl ring can be preferably used.

[0106] In addition, from the viewpoints of solubility or molecular structure diversity, compounds having a coordination bond are preferred. In terms of a small half-value width and high-efficiency light emission, boron-containing compounds such as boron fluoride complexes are preferred.

[0107] Among them, in terms of imparting a high fluorescence quantum yield and good durability, pyrromethene derivatives can be preferably used. More preferably, it is a compound represented by the general formula (1).

[0108] [Chemical formula 1]

[0109]

[0110] X is C-R 7 or N. R 1 ~R 9 may be the same or different from each other, and are selected from hydrogen, alkyl, cycloalkyl, heterocyclic group, alkenyl, cycloalkenyl, alkynyl, hydroxyl group, thiol group, alkoxy group, alkylthio group, aryl ether group, aryl thioether group, aryl, heteroaryl, halogen, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group, nitro group, silyl group, siloxy group, boryl group, sulfo group, phosphine oxide group, and a condensed ring and an aliphatic ring formed between adjacent substituents.

[0111] Among all the above groups, hydrogen can be deuterium. The same applies to the compounds or their partial structures described below. In addition, in the following description, for example, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms means an aryl group having a total of 6 to 40 carbon atoms including the carbon atoms contained in the substituents substituted in the aryl group. The same applies to other substituents for which the number of carbon atoms is specified.

[0112] In addition, among all the groups described above, when they are substituted, the substituents are preferably groups selected from alkyl, cycloalkyl, heterocyclic group, alkenyl, cycloalkenyl, alkynyl, hydroxyl, mercapto, alkoxy, alkylthio, aryl ether group, aryl thioether group, aryl, heteroaryl, halogen, cyano, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group, nitro group, silyl group, siloxanyl group, boron group, sulfo group and phosphine oxide group. Further preferably, they are the specific substituents regarded as preferred in the description of each substituent. In addition, these substituents may be further substituted by the above-mentioned substituents.

[0113] In the case of "substituted or unsubstituted", "unsubstituted" means that the substituent is a hydrogen atom or a deuterium atom. In the compounds or partial structures described below, the case of "substituted or unsubstituted" is the same as described above.

[0114] Among all the groups described above, the term "alkyl" refers to saturated aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, etc. It may have substituents or may not have substituents. The additional substituents in the case of being substituted are not particularly limited. For example, alkyl, halogen, aryl, heteroaryl, etc. can be cited. The same applies to the following descriptions. In addition, the number of carbon atoms of the alkyl is not particularly limited. In terms of ease of acquisition or cost, it is preferably in the range of 1 or more and 20 or less, more preferably in the range of 1 or more and 8 or less.

[0115] The term "cycloalkyl" refers to saturated alicyclic hydrocarbon groups such as cyclopropyl, cyclohexyl, norbornyl, adamantyl, etc. It may have substituents or may not have substituents. The number of carbon atoms in the alkyl part is not particularly limited, and is preferably in the range of 3 or more and 20 or less.

[0116] The term "heterocyclic group" refers to aliphatic rings having atoms other than carbon in the ring, such as pyran ring, piperidine ring, cyclic amide, etc. It may have substituents or may not have substituents. The number of carbon atoms of the heterocyclic group is not particularly limited, and is preferably in the range of 2 or more and 20 or less.

[0117] The term "alkenyl" refers to unsaturated aliphatic hydrocarbon groups containing double bonds such as vinyl, allyl, butadienyl, etc. It may have substituents or may not have substituents. The number of carbon atoms of the alkenyl is not particularly limited, and is preferably in the range of 2 or more and 20 or less.

[0118] The term "cycloalkenyl" refers to unsaturated alicyclic hydrocarbon groups containing double bonds such as cyclopentenyl, cyclopentadienyl, cyclohexenyl, etc. It may have substituents or may not have substituents.

[0119] The so-called alkynyl group, for example, represents an unsaturated aliphatic hydrocarbon group containing a triple bond such as ethynyl group, and may or may not have a substituent. The number of carbon atoms of the alkynyl group is not particularly limited, and preferably ranges from 2 or more to 20 or less.

[0120] The so-called alkoxy group, for example, represents a functional group such as methoxy group, ethoxy group, propoxy group, etc., in which an aliphatic hydrocarbon group is bonded through an ether bond, and the aliphatic hydrocarbon group may or may not have a substituent. The number of carbon atoms of the alkoxy group is not particularly limited, and preferably ranges from 1 or more to 20 or less.

[0121] The so-called alkylthio group is an alkylthio group in which the oxygen atom of the ether bond of the alkoxy group is replaced by a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. The number of carbon atoms of the alkylthio group is not particularly limited, and preferably ranges from 1 or more to 20 or less.

[0122] The so-called aryl ether group, for example, represents a functional group such as phenoxy group, in which an aromatic hydrocarbon group separated by an ether bond is bonded, and the aromatic hydrocarbon group may or may not have a substituent. The number of carbon atoms of the aryl ether group is not particularly limited, and preferably ranges from 6 or more to 40 or less.

[0123] The so-called aryl thioether group is an aryl thioether group in which the oxygen atom of the ether bond of the aryl ether group is replaced by a sulfur atom. The aromatic hydrocarbon group in the aryl thioether group may or may not have a substituent. The number of carbon atoms of the aryl thioether group is not particularly limited, and preferably ranges from 6 or more to 40 or less.

[0124] The so-called aryl group, for example, represents aromatic hydrocarbon groups such as phenyl group, biphenyl group, terphenyl group, naphthyl group, fluorenyl group, benzo[h]fluorenyl group, dibenzo[h,i]fluorenyl group, phenanthryl group, anthryl group, benzo[a]phenanthryl group, benzo[a]anthryl group, pyrenyl group, fluoranthenyl group, triphenylenyl group, benzo[a]fluoranthenyl group, dibenzo[a,h]anthryl group, perylenyl group, helicenyl group, etc. Among them, the group selected from phenyl group, biphenyl group, terphenyl group, naphthyl group, fluorenyl group, phenanthryl group, anthryl group, pyrenyl group, fluoranthenyl group and triphenylenyl group is preferred. The aryl group may or may not have a substituent. The number of carbon atoms of the aryl group is not particularly limited, and preferably ranges from 6 or more to 40 or less, more preferably from 6 or more to 30 or less.

[0125] When R 1 ~R 9 is a substituted or unsubstituted aryl group, as the aryl group, the group selected from phenyl group, biphenyl group, terphenyl group, naphthyl group, fluorenyl group, phenanthryl group and anthryl group is preferred, and the group selected from phenyl group, biphenyl group, terphenyl group and naphthyl group is more preferred. Further preferably, the group selected from phenyl group, biphenyl group and terphenyl group is preferred, and phenyl group is particularly preferred.

[0126] In the case where each substituent is further substituted with an aryl group, the aryl group is preferably a group selected from phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, and anthryl groups, more preferably a group selected from phenyl, biphenyl, terphenyl, and naphthyl groups. Particularly preferably, it is a phenyl group.

[0127] The so-called heteroaryl group, for example, represents a cyclic aromatic group having an atom other than carbon in one or more rings, such as pyridyl, furyl, thienyl, quinolinyl, isoquinolinyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, naphthyridinyl, cinnolinyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzofuryl, benzothienyl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl, benzocarbazolyl, carbolinyl group, indolocarbazolyl, benzofurocarbazolyl, benzothienocarbazolyl, indeno[1,2-b]carbazolyl, benzoquinolinyl, acridinyl, dibenzoacridinyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, phenanthrolinyl, etc. Among them, the so-called naphthyridinyl group represents any one of 1,5-naphthyridinyl, 1,6-naphthyridinyl, 1,7-naphthyridinyl, 1,8-naphthyridinyl, 2,6-naphthyridinyl, and 2,7-naphthyridinyl groups. The heteroaryl group may or may not have a substituent. The number of carbon atoms of the heteroaryl group is not particularly limited, and it is preferably in the range of 2 or more and 40 or less, more preferably 2 or more and 30 or less.

[0128] When R 1 ~R 9 is a substituted or unsubstituted heteroaryl group, as the heteroaryl group, it is preferably a group selected from pyridyl, furyl, thienyl, quinolinyl, pyrimidinyl, triazinyl, benzofuryl, benzothienyl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, and phenanthrolinyl groups, more preferably a group selected from pyridyl, furyl, thienyl, and quinolinyl groups. Particularly preferably, it is a pyridyl group.

[0129] In the case where each substituent is further substituted with a heteroaryl group, as the heteroaryl group, it is preferably a group selected from pyridyl, furyl, thienyl, quinolinyl, pyrimidinyl, triazinyl, benzofuryl, benzothienyl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, and phenanthrolinyl groups, more preferably a group selected from pyridyl, furyl, thienyl, and quinolinyl groups. Particularly preferably, it is a pyridyl group.

[0130] The so-called halogen means an atom selected from fluorine, chlorine, bromine and iodine. In addition, the carbonyl group, carboxyl group, ester group, carbamoyl group may or may not have a substituent. Here, examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, etc., and these substituents may be further substituted.

[0131] The so-called amino group is a substituted or unsubstituted amino group. Examples of the substituent in the case of substitution include: an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, etc. As the aryl group and heteroaryl group, a group selected from a phenyl group, a naphthyl group, a pyridyl group and a quinolinyl group is preferred. These substituents may be further substituted. The carbon number is not particularly limited, and preferably ranges from 2 or more to 50 or less, more preferably from 6 or more to 40 or less, and particularly preferably from 6 or more to 30 or less.

[0132] The so-called silyl group means, for example, an alkylsilyl group such as trimethylsilyl group, triethylsilyl group, tert-butyldimethylsilyl group, propyldimethylsilyl group, vinyldimethylsilyl group, or an arylsilyl group such as phenyldimethylsilyl group, tert-butyldiphenylsilyl group, triphenylsilyl group, trinaphthylsilyl group. The substituent on the silicon may be further substituted. The carbon number of the silyl group is not particularly limited, and preferably ranges from 1 or more to 30 or less.

[0133] The so-called siloxy group means, for example, a silicon compound group such as trimethylsiloxy group having an ether bond interposed therebetween. The substituent on the silicon may be further substituted. In addition, the so-called boron group is a substituted or unsubstituted boron group. Examples of the substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group, a hydroxyl group, etc. Among them, a group selected from an aryl group and an aryl ether group is preferred. In addition, the so-called sulfo group is a substituted or unsubstituted sulfo group. Examples of the substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group, etc. Among them, a linear alkyl group or an aryl group is preferred.

[0134] In addition, the so-called phosphine oxide group refers to -P(=O)R 10 R 11 represents the group. R 10 R 11 is selected from the same group as R 1 ~R 9 in the same group.

[0135] The so-called condensed ring and aliphatic ring formed between adjacent substituents means any two adjacent substituents (for example, R in the general formula (1)) 1 and R 2Bonded to each other to form a conjugated or non-conjugated cyclic skeleton. As the constituent elements of such condensed rings and aliphatic rings, in addition to carbon, elements selected from nitrogen, oxygen, sulfur, phosphorus, and silicon may also be included. In addition, these condensed rings and aliphatic rings may further condense with other rings.

[0136] The compound represented by the general formula (1) exhibits a high luminescence quantum yield and a small half-value width of the luminescence spectrum, so both efficient color conversion and high color purity can be achieved. Furthermore, the compound represented by the general formula (1) can adjust various properties or physical properties such as luminescence efficiency, color purity, thermal stability, photostability, and dispersibility by introducing appropriate substituents to appropriate positions. For example, compared with the case where R 1 、R 3 、R 4 and R 6 are all hydrogen, when at least one of R 1 、R 3 、R 4 and R 6 is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, it shows better thermal stability and photostability.

[0137] When at least one of R 1 、R 3 、R 4 and R 6 is a substituted or unsubstituted alkyl group, as the alkyl group, preferably an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, etc. Furthermore, as the alkyl group, from the viewpoint of excellent thermal stability, preferably a group selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. In addition, from the viewpoint of preventing concentration quenching and increasing the luminescence quantum yield, as the alkyl group, more preferably the sterically bulky tert-butyl group. On the other hand, from the viewpoints of ease of synthesis and ease of obtaining raw materials, as the alkyl group, methyl can also be preferably used.

[0138] When at least one of R 1 、R 3 、R 4 and R 6 is a substituted or unsubstituted aryl group, as the aryl group, preferably a group selected from phenyl, biphenyl, terphenyl, and naphthyl, and further preferably phenyl, biphenyl. Particularly preferably phenyl.

[0139] When at least one of R 1 、R 3 、R 4 and R 6When at least one of is a substituted or unsubstituted heteroaryl group, the heteroaryl group is preferably a group selected from pyridyl, quinolyl and thienyl, more preferably pyridyl or quinolyl, and particularly preferably pyridyl.

[0140] In R 1 , R 3 , R 4 and R 6 All of them may be the same or different, and when they are substituted or unsubstituted alkyl groups, they are preferred because they have good solubility in the binder resin or solvent. In such a case, the alkyl group is preferably a methyl group from the viewpoint of ease of synthesis and ease of obtaining raw materials.

[0141] In R 1 , R 3 , R 4 and R 6 In the case where they are the same or different, and are substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl, they show better thermal stability and light stability, and thus are preferred. In such a case, more preferably R 1 , R 3 , R 4 and R 6 Each of them may be the same as or different from each other and is a substituted or unsubstituted aryl group.

[0142] Although there are substituents that improve multiple properties, there are limited substituents that show sufficient performance in all properties. It is particularly difficult to achieve both high luminous efficiency and high color purity. Therefore, a compound that has achieved a balance in terms of luminous properties or color purity can be obtained by introducing a variety of substituents into the compound represented by general formula (1).

[0143] Especially in R 1 , R 3 , R 4 and R 6 In the case where they are the same or different and are substituted or unsubstituted aryl groups, for example, R 1 ≠R 4 , R 3 ≠R 6 , R 1 ≠R 3 or R 4 ≠R 6 Here, “≠” indicates different structures. For example, R 1 ≠R 4 Represents R 1 With R 4is the base for different structures. By introducing various substituents as described above, an aryl group that affects color purity and an aryl group that affects luminous efficiency can be introduced simultaneously, so that fine adjustment can be performed.

[0144] Among them, from the viewpoint of improving luminous efficiency and color purity with good balance, R is preferably 1 ≠R 3 or R 4 ≠R 6 . In the above case, with respect to the compound represented by the general formula (1), one or more aryl groups that affect color purity can be introduced into the pyrrole rings on both sides, and an aryl group that affects luminous efficiency can be introduced at other positions. Therefore, the properties of the above two can be maximally improved. In addition, in the case of R 1 ≠R 3 or R 4 ≠R 6 , from the viewpoint of improving both heat resistance and color purity, it is more preferably R 1 =R 6 and R 3 =R 4 .

[0145] As the aryl group that affects color purity, an aryl group substituted with an electron-donating group is preferred. An electron-donating group, in organic electronics theory, refers to a group that supplies electrons to the atom group to which it is substituted through an inductive effect or a resonance effect. As the electron-donating group, a group that takes a negative value as the substituent constant (σp (para)) of the Hammett equation can be cited. The substituent constant (σp (para)) of the Hammett equation can be cited from the 5th revised edition of the Basic Edition of the Chemical Handbook (page II-380).

[0146] As a specific example of the electron-donating group, for example, an alkyl group (σp of methyl: -0.17) or an alkoxy group (σp of methoxy group: -0.27), an amino group (-NH2's σp: -0.66), etc. can be cited. Particularly preferred are an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, and more preferably a group selected from methyl, ethyl, tert-butyl, and methoxy. From the viewpoint of dispersibility, tert-butyl or methoxy is particularly preferred. When these are used as the electron-donating group, in the compound represented by the general formula (1), extinction caused by the aggregation of molecules with each other can be prevented. The substitution position of the substituent is not particularly limited, but in order to improve the light stability of the compound represented by the general formula (1), it is necessary to suppress the bending of the bond, so it is preferably bonded to the meta-position or para-position with respect to the bonding position to the pyrrole methylene skeleton. On the other hand, as the aryl group that mainly affects luminous efficiency, an aryl group having a bulky substituent such as tert-butyl, adamantyl, or methoxy is preferred.

[0147] At R 1 、R 3 、R 4 and R 6 may be the same or different, and when they are aryl groups which may or may not be substituted, preferably R 1 、R 3 、R 4 and R 6 may be the same or different, and are phenyl groups which may or may not be substituted. At this time, R 1 、R 3 、R 4 and R 6 are more preferably selected from Ar-1 to Ar-6 below. In the said case, the combination of R 1 、R 3 、R 4 and R 6 is not particularly limited.

[0148] [Chemical formula 2]

[0149]

[0150] R 2 and R 5 are preferably any one of hydrogen, alkyl, carbonyl, ester group and aryl. Among them, from the viewpoint of thermal stability, hydrogen or alkyl is preferred, and from the viewpoint of easily obtaining a narrow half-value width in the emission spectrum, hydrogen is more preferred.

[0151] R 8 and R 9 are preferably groups selected from alkyl, aryl, heteroaryl, alkoxy, aryl ether group, fluorine, fluorinated alkyl, fluorinated heteroaryl or fluorinated aryl, fluorinated alkoxy, fluorinated aryl ether group and cyano group. From the aspect of being stable to excitation light and obtaining a higher fluorescence quantum yield, fluorine, cyano group or fluorinated aryl is more preferred. From the aspect of ease of synthesis, fluorine or cyano group is further preferred. Furthermore, any one of R 8 or R 9 is preferably a cyano group. By introducing a cyano group, the durability will be improved.

[0152] Here, the so-called fluorinated aryl means an aryl group containing fluorine, and examples thereof include fluorophenyl, trifluoromethylphenyl and pentafluorophenyl. The so-called fluorinated heteroaryl means a heteroaryl group containing fluorine, and examples thereof include fluoropyridyl, trifluoromethylpyridyl and trifluoropyridyl. The so-called fluorinated alkyl means an alkyl group containing fluorine, and examples thereof include trifluoromethyl or pentafluoroethyl.

[0153] In addition, in general formula (1), from the viewpoint of light stability, X is preferably C-R 7 . When X is C-R 7When the substituent R 7 greatly affects the durability of the compound represented by the general formula (1), that is, the temporal decrease in the luminescence intensity of the compound. Specifically, when R 7 is hydrogen, the reactivity of this site is high, so this site easily reacts with moisture or oxygen in the air. This causes the decomposition of the compound represented by the general formula (1). In addition, when R 7 is a substituent with a large degree of freedom of movement of the molecular chain such as an alkyl group, the reactivity does decrease, but the compounds condense with each other over time in the color conversion layer, resulting in a decrease in the luminescence intensity caused by concentration quenching. Therefore, R 7 is preferably a rigid group with a small degree of freedom of movement and difficult to cause condensation. Specifically, it is preferably any one of a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.

[0154] In terms of providing a higher fluorescence quantum yield and being more difficult to thermally decompose, and also from the viewpoint of photostability, it is preferred that X is C-R 7 and R 7 is a substituted or unsubstituted aryl group. As the aryl group, from the viewpoint of not damaging the emission wavelength, it is preferably a group selected from phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, and anthryl.

[0155] Furthermore, in order to improve the photostability of the compound represented by the general formula (1), it is necessary to moderately suppress the bending of the carbon-carbon bond of the R 7 with the pyrromethine skeleton. The reason is that if the bending is too large, the reactivity with respect to the excitation light becomes high, etc., and the photostability decreases. From this viewpoint, as R 7 , it is preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, more preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group. Particularly preferably, it is a substituted or unsubstituted phenyl group.

[0156] In addition, R 7 is preferably a substituent with a moderately large volume. By R 7 having a certain degree of large volume, the condensation of molecules can be prevented, and as a result, the luminescence efficiency or durability of the compound represented by the general formula (1) is further improved.

[0157] As a further preferred example of such a large-volume substituent, the structure of R 7 represented by the following general formula (2) can be cited.

[0158] [Chemical formula 3]

[0159]

[0160] In general formula (2), r is selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocyclic group, alkenyl, cycloalkenyl, alkynyl, hydroxyl group, mercapto group, alkoxy group, alkylthio group, aryl ether group, aryl thioether group, aryl, heteroaryl, halogen, cyano group, aldehyde group, carbonyl group, carboxyl group, ester group, carbamoyl group, amino group, nitro group, silyl group, siloxanyl group, boron group, sulfo group, and phosphine oxide group. k is an integer of 1 to 3. When k is 2 or more, r may be the same or different.

[0161] From the viewpoint of providing a higher luminescence quantum yield, r is preferably a substituted or unsubstituted aryl group. Among the aryl groups, phenyl or naphthyl is particularly preferably cited as an example. When r is an aryl group, k in general formula (2) is preferably 1 or 2, and more preferably 2 from the viewpoint of further preventing the aggregation of molecules. Further, when k is 2 or more, at least one of r is preferably substituted with an alkyl group. As the alkyl group in this case, a group selected from methyl, ethyl, and tert-butyl is particularly preferably cited as an example from the viewpoint of thermal stability.

[0162] In addition, from the viewpoints of controlling the fluorescence wavelength or absorption wavelength, or improving the compatibility with the solvent, r is preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a halogen, and more preferably a group selected from methyl, ethyl, tert-butyl, and methoxy group. From the viewpoint of dispersibility, tert-butyl or methoxy group is particularly preferably cited. It is more effective for preventing extinction caused by the aggregation of molecules that r is tert-butyl or methoxy group.

[0163] In addition, as another form of the compound represented by general formula (1), it is preferably that 1 ~R 7 at least one of them is an electron-withdrawing group. Particularly preferably, (1) at least one of 1 ~R 6 is an electron-withdrawing group; (2) 7 R is an electron-withdrawing group; or (3) at least one of 1 ~R 6 is an electron-withdrawing group and 7 R is an electron-withdrawing group. By introducing an electron-withdrawing group into the pyrromethine skeleton of the compound as described above, the electron density of the pyrromethine skeleton can be significantly reduced. As a result, the stability of the compound with respect to oxygen is further improved, and as a result, the durability of the compound can be further improved.

[0164] An electron-withdrawing group, also known as an electron-attracting group, in the theory of organic electronics is a group that attracts electrons from a substituted atomic group through an inductive effect or a resonance effect. As an electron-withdrawing group, a group that takes a positive value as the substituent constant (σp (para position)) of the Hammett's rule can be cited. The substituent constant (σp (para)) of the Hammett's rule can be cited from the 5th revised edition of the Basic Edition of Chemical Handbook (page II-380). Furthermore, although there are examples in which a phenyl group also takes a positive value as described above, in the present invention, the phenyl group is not included in the electron-withdrawing group.

[0165] Examples of the electron-withdrawing group include, for example: -F (σp: +0.06), -Cl (σp: +0.23), -Br (σp: +0.23), -I (σp: +0.18), -CO2R 12 (σp: R 12 is +0.45 when R is an ethyl group), -CONH2 (σp: +0.38), -COR 12 (σp: R 12 is +0.49 when R is a methyl group), -CF3 (σp: +0.50), -SO2R 12 (σp: R 12 is +0.69 when R is a methyl group), -NO2 (σp: +0.81), etc. R 12 each independently represents a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring-forming carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring-forming atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 1 to 30 carbon atoms. Specific examples of these groups can be the same as those described above.

[0166] In the general formula (1), at least one of R 2 and R 5 is preferably an electron-withdrawing group. The reason is that R 2 and R 5 in the general formula (1) are substitution positions that have a great influence on the electron density of the pyrrole methylene skeleton. By introducing an electron-withdrawing group into R 2 and R 5 , the electron density of the pyrrole methylene skeleton can be efficiently reduced, and the stability to oxygen can be further improved, so the durability can be further improved.

[0167] Furthermore, in the general formula (1), R 2 and R 5 are more preferably electron-withdrawing groups. The reason is that the stability of the compound represented by the general formula (1) to oxygen is further improved, and the durability can be greatly improved.

[0168] As an electron-withdrawing group, a group containing a fluorine atom is preferred. By being a group containing a fluorine atom, the electron density of the pyrromethene skeleton can be further reduced, the stability of the compound represented by the general formula (1) to oxygen is improved, and the durability can be improved.

[0169] Examples of preferred electron-withdrawing groups include: fluorine, fluoroaryl, fluorinated heteroaryl, fluoroalkyl, substituted or unsubstituted acyl group, substituted or unsubstituted ester group, substituted or unsubstituted amide group, substituted or unsubstituted sulfonyl group, substituted or unsubstituted sulfonate group, substituted or unsubstituted sulfonamide group, or cyano group. The reason is that these groups are difficult to undergo chemical decomposition.

[0170] Examples of more preferred electron-withdrawing groups include: fluoroalkyl, substituted or unsubstituted acyl group, substituted or unsubstituted ester group, substituted or unsubstituted amide group, substituted or unsubstituted sulfonyl group, substituted or unsubstituted sulfonate group, substituted or unsubstituted sulfonamide group, or cyano group. The reason is that these groups have the effect of preventing concentration quenching and improving the luminescence quantum yield. A particularly preferred electron-withdrawing group is a substituted or unsubstituted ester group.

[0171] Examples of further preferred electron-withdrawing groups include: fluoroacyl group, fluoroester group, fluoroamide group, fluorosulfonyl group, fluorosulfonate group, fluorosulfonamide group. These groups can efficiently reduce the electron density of the pyrrometheneboron complex skeleton. As a result, the stability of the compound represented by the general formula (1) to oxygen is improved, and the durability can be further improved.

[0172] Among them, since the durability can be improved without reducing the color purity, it is preferably R 2 and R 5 At least one of them may be the same or different, and is a substituted or unsubstituted ester group. In particular, from the viewpoint of improving durability, it is particularly preferably that R 2 and R 5 are each the same or different and are a substituted or unsubstituted ester group.

[0173] As a preferred example of the compound represented by the general formula (1), the following cases can be cited: R 1 , R 3 , R 4 and R 6 are each the same or different and are a substituted or unsubstituted alkyl group, and further X is C-R 7 and R 7 is a group represented by the general formula (2). In the above case, in R 7 , r is particularly preferably a substituted or unsubstituted phenyl group.

[0174] Further, as another preferred example of the compound represented by the general formula (1), the following cases may be mentioned: R 1 , R 3 , R 4 and R 6 may each be the same or different and are selected from the above-mentioned Ar-1 to Ar-6. Further, X is C-R 7 and R 7 is a group represented by the general formula (2). In the said case, in R 7 , it is more preferably that r is tert-butyl or methoxy, and particularly preferably that r is methoxy.

[0175] Further, as another preferred example of the compound represented by the general formula (1), the following cases may be mentioned: R 1 , R 3 , R 4 and R 6 may each be the same or different and are a substituted or unsubstituted alkyl group, and R 2 and R 5 may each be the same or different and are a substituted or unsubstituted ester group. Further, X is C-R 7 and R 7 is a group represented by the general formula (2). In the said case, in R 7 , r is particularly preferably a substituted or unsubstituted phenyl group.

[0176] Further, as another preferred example of the compound represented by the general formula (1), the following cases may be mentioned: R 1 , R 3 , R 4 and R 6 may each be the same or different and are selected from the above-mentioned Ar-1 to Ar-6, and R 2 and R 5 may each be the same or different and are a substituted or unsubstituted ester group. Further, X is C-R 7 and R 7 is a group represented by the general formula (2). In the said case, in R 7 , it is more preferably that r is tert-butyl or methoxy, and particularly preferably that r is methoxy.

[0177] An example of the compound represented by the general formula (1) is shown below, but the compound is not limited to these.

[0178] [Chemical formula 4]

[0179]

[0180] [Chemical formula 5]

[0181]

[0182] [Chemical Formula 6]

[0183]

[0184] [Chemical Formula 7]

[0185]

[0186] [Chemical Formula 8]

[0187]

[0188] [Chemical Formula 9]

[0189]

[0190] [Chemical Formula 10]

[0191]

[0192] [Chemical Formula 11]

[0193]

[0194] [Chemical Formula 12]

[0195]

[0196] [Chemical Formula 13]

[0197]

[0198] The compound represented by the general formula (1) can be synthesized by the methods described in, for example, Japanese Patent Publication No. 8-509471 or Japanese Patent Application Laid-Open No. 2000-208262. That is, the target pyrromethene-based metal complex can be obtained by reacting a pyrromethene compound with a metal salt in the presence of a base.

[0199] In addition, regarding the synthesis of pyrromethene-boron fluoride complexes, reference can be made to the methods described in "Journal of Organic Chemistry (J. Org. Chem.)", vol. 64, No. 21, pp. 7813-7819 (1999), "Angewandte Chemie International Edition (Engl.)", vol. 36, pp. 1333-1335 (1997), etc., to synthesize the compound represented by the general formula (1). For example, the following method can be cited: After heating the compound represented by the following general formula (3) and the compound represented by the general formula (4) in 1,2-dichloroethane in the presence of phosphorus oxychloride, reacting with the compound represented by the following general formula (5) in 1,2-dichloroethane in the presence of triethylamine, thereby obtaining the compound represented by the general formula (1). However, the present invention is not limited thereto. Here, R 1 ~R 9 is the same as the above description. J represents a halogen.

[0200] [Chemical Formula 14]

[0201]

[0202] Furthermore, when introducing an aryl group or a heteroaryl group, a method of forming a carbon-carbon bond by coupling reaction of a halogenated derivative with boric acid or a boric acid ester derivative can be cited, but the present invention is not limited thereto. Similarly, when introducing an amino group or a carbazolyl group, a method of forming a carbon-nitrogen bond by coupling reaction of a halogenated derivative with an amine or a carbazole derivative under a metal catalyst such as palladium can also be cited, but the present invention is not limited thereto.

[0203] In addition to the compound represented by the general formula (1), the color conversion layer of the embodiment of the present invention may appropriately contain other compounds as needed. For example, in order to further improve the energy transfer efficiency from the excitation light to the compound represented by the general formula (1), a co-dopant such as rubrene may also be contained. In addition, when a luminescent color other than the luminescent color of the compound represented by the general formula (1) is to be added, an organic luminescent material as desired can be added, for example: organic luminescent materials such as coumarin-based pigments and rhodamine-based pigments. In addition to these organic luminescent materials, known luminescent materials such as inorganic phosphors, fluorescent pigments, fluorescent dyes, quantum dots, and compounds that emit delayed fluorescence can also be added in combination.

[0204] The following shows an example of an organic luminescent material other than the compound represented by the general formula (1), but the present invention is not particularly limited to these.

[0205] [Chemical Formula 15]

[0206]

[0207] As inorganic phosphors, for example, there are SrAl2O4:Eu, Y2SiO5:Ce,Tb, MgAl 11 O 19 :Ce,Tb, Sr7Al 12 O 25 :Eu, MgGa2S4:Eu, CaGa2S4:Eu, SrGa2S4:Eu, BaGa2S4:Eu and other green phosphors; or Sr5(PO4)3Cl:Eu, (SrCaBa)5(PO4)3Cl:Eu, (BaCa)5(PO4)3Cl:Eu, B5O9Cl:Eu,Mn, Mg(PO4)6Cl2:Eu,Mn, Ca(PO4)6Cl2:Eu,Mn, Sr(PO4)6Cl2:Eu,Mn, Ba(PO4)6Cl2:Eu,Mn and other blue phosphors; or for example, Y2O2S:Eu, La2O2S:Eu, Y2O3:Eu, Gd2O2S:Eu, K2SiF6:Mn and other red phosphors. In addition, the following can also be listed: Y3(Al,Ga)5O 12 :Ce, (Y,Gd)3Al5O 12 :Ce, Lu3Al5O 12 :Ce, Y3Al5O 12 :Ce and other YAG-based phosphors, Tb3Al5O 12 :Ce and other TAG-based phosphors, (Ba,Sr)2SiO4:Eu-based phosphors or Ca3Sc2Si3O 12 :Ce-based phosphors, (Sr,Ba,Mg)2SiO4:Eu and other silicate-based phosphors, (Ca,Sr)2Si5N8:Eu, (Ca,Sr)AlSiN3:Eu, CaSiAlN3:Eu and other nitride-based phosphors, Cax(Si,Al) 12 (O,N) 16 :Eu and other oxynitride-based phosphors, and (Ba,Sr,Ca)Si2O2N2:Eu-based phosphors, Ca8MgSi4O 16 Cl2:Eu-based phosphors, SrAl2O4:Eu,Sr4Al 14 O 25 :Eu and other phosphors.

[0208] Quantum dots are phosphors with excellent quantum efficiency. By confining electrons, holes, or excitons in all directions in three-dimensional space in semiconductor crystals of nanoscale size (e.g., about 2 nm to 10 nm in diameter), they have discrete energy levels. By changing the size of the dots, the peak wavelength (emission color) of the emitted light can be freely selected, etc. As materials used in quantum dots, examples include materials formed by combining divalent cations such as Zn, Cd, Pb, etc. with divalent anions such as O, S, Se, Te, etc. (e.g., cadmium selenide (CdSe), zinc sulfide (ZnS), etc.), materials formed by combining trivalent cations such as Ga, In, etc. with trivalent anions such as P, As, Sb, etc. (e.g., indium phosphide (InP), gallium arsenide (GaAs), etc.), and chalcopyrite-type compounds (CuInSe2, etc.). As a preferred example of the material of the quantum dot phosphor, CdSe can be cited.

[0209] Regarding compounds that emit delayed fluorescence, they are explained on pages 87 to 103 of "The Most Advanced Organic EL" (edited by Chiba Ya and Hiro Fujimoto, published by CMC). In the said literature, it is explained that: by making the energy levels of the singlet excited state and the triplet excited state of the luminescent material close, the reverse energy transfer from the triplet excited state with a low migration probability to the singlet excited state is usually generated with high efficiency, and the generation mechanism of thermally activated delayed fluorescence (TADF) and delayed fluorescence is manifested. The emission of delayed fluorescence can be confirmed by transient photoluminescence (PL) measurement.

[0210] In this specification, a compound that migrates from the triplet excited state to the singlet excited state with high efficiency and emits fluorescence, including a compound that exhibits thermally activated delayed fluorescence, is expressed as a "compound that emits delayed fluorescence".

[0211] Generally, fluorescence emission occurs from the singlet excited state generated after the luminescent material is photoexcited. The triplet excited state of the luminescent material generated by intersystem crossing thermally deactivates and does not emit fluorescence at room temperature. On the other hand, as described above, even if a compound that emits delayed fluorescence generates a triplet excited state, it will quickly transform into a singlet excited state and then emit fluorescence. Therefore, the triplet excited state that does not contribute to luminescence in ordinary fluorescent luminescent materials can also contribute to fluorescence emission. Therefore, if a compound that exhibits thermally activated delayed fluorescence is used, high-efficiency luminescence can be obtained.

[0212] In addition, the triplet excited state of a compound that emits delayed fluorescence can be rapidly converted into a singlet excited state, and thus has the characteristic of being less likely to generate singlet oxygen. It is considered that singlet oxygen has strong oxidizing power, and thus singlet oxygen causes deterioration due to the oxidation of the luminescent material. It is considered that singlet oxygen is generated through the exchange of electrons and energy between the triplet excited state of the luminescent material and the ground state triplet oxygen molecule. As described above, a compound that emits delayed fluorescence has the property that the triplet excited state is rapidly converted into a singlet excited state, that is, the lifetime of the triplet excited state is short. Therefore, the probability of direct collision between the triplet excited state of the luminescent material and the ground state triplet oxygen becomes small, and singlet oxygen is less likely to be generated. Moreover, based on the above characteristics, it has been found that when a compound showing thermally activated delayed fluorescence is used, the deterioration of the luminescent material is suppressed, the temporal change in chromaticity is suppressed, and the durability of the luminescent material can be improved.

[0213] As a molecular design for making the energy level of the singlet excited state close to the energy level of the triplet excited state, it is effective to bond an electron-donating skeleton and an electron-accepting skeleton within the same molecule. Thereby, the HOMO (Highest Occupied Molecular Orbital) orbital and the LUMO (Lowest Unoccupied Molecular Orbital) orbital can be separated within the molecule. The electron-donating skeleton and the electron-accepting skeleton can be directly bonded or can be bonded via a linking group. As the linking group in this case, a skeleton containing an aromatic hydrocarbon is preferably used.

[0214] Examples of the electron-donating skeleton include a skeleton having an amine nitrogen atom. Among them, a skeleton containing a diarylamine or a triarylamine, a skeleton containing a carbazole, a skeleton containing a benzocarbazole, a skeleton containing an indolocarbazole, a skeleton containing a phenoxazine, and a skeleton containing a phenothiazine are preferably used. Among these, a skeleton containing a carbazole, a skeleton containing a benzocarbazole, a skeleton containing an indolocarbazole, and a skeleton containing a phenoxazine are more preferably used, and a skeleton containing a carbazole and a skeleton containing a phenoxazine are further preferably used.

[0215] On the other hand, examples of the electron-accepting skeleton generally include a skeleton containing a substituent having an electron-withdrawing property. An electron-withdrawing group, also referred to as an electron-attracting group, in organic electronic theory, is a group that attracts electrons from a substituted atomic group through an inductive effect or a resonance effect. As the electron-withdrawing group, an electron-withdrawing group that takes a positive value as the substituent constant (σp (para position)) of Hammett's rule can be cited. The substituent constant (σp (para position)) of Hammett's rule can be cited from the 5th revised edition of the Basic Edition of the Chemical Handbook (page II-380).

[0216] Furthermore, although there are examples where phenyl also takes a positive value, phenyl is not included in the electron-withdrawing groups of the present application.

[0217] Examples of the electron-withdrawing group include, for example: -F (σp: +0.20), -Cl (σp: +0.28), -Br (σp: +0.30), -I (σp: +0.30), -CO2R 12 (σp: R 12 is +0.45 when R is ethyl), -CONH2 (σp: +0.38), -COR 12 (σp: R 12 is +0.49 when R is methyl), -CF3 (σp: +0.51), -SO2R 12 (σp: R 12 is +0.69 when R is methyl), -NO2 (σp: +0.81), etc. R 12 each independently represents a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms in the ring formation, a substituted or unsubstituted heterocyclic group having 5 to 30 ring-forming atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 1 to 30 carbon atoms. Specific examples of each of these groups include the same examples as those described above.

[0218] Among them, a skeleton of a heteroaryl containing a partial structure in which a carbon atom and a nitrogen atom are bonded by a double bond, a skeleton containing a fluorinated substituent, a skeleton containing a cyano group, a skeleton containing a carbonyl group, a skeleton containing a sulfoxide or a disulfoxide, and a skeleton containing a phosphine oxide group are preferred. Among these, from the viewpoint of the stability of the compound, a skeleton of a heteroaryl containing a partial structure in which a carbon atom and a nitrogen atom are bonded by a double bond, a skeleton containing a fluorinated substituent, and a skeleton containing a cyano group are further preferred.

[0219] In the skeleton of a heteroaryl containing a partial structure in which a carbon atom and a nitrogen atom are bonded by a double bond, specifically, a skeleton containing pyridine, pyrimidine, pyrazine, triazine, quinoline, quinoxaline, quinazoline, or phenanthroline is preferred. Among them, a skeleton containing pyrimidine, triazine, quinoxaline, or quinazoline is more preferred, and a skeleton containing triazine is further preferred.

[0220] In the skeleton containing a fluorinated substituent, a skeleton containing a fluorinated aryl or a fluoroalkyl is more preferred. As the skeleton containing a fluorinated aryl, a fluorinated benzene ring is preferred. Specifically, a skeleton containing fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, or pentafluorobenzene is more preferred. As the skeleton containing a fluoroalkyl, a skeleton containing a benzene ring substituted with a trifluoromethyl group is preferred. Among these, a skeleton containing mono(trifluoromethyl)benzene or bis(trifluoromethyl)benzene is more preferred.

[0221] In a skeleton having a cyano group, a skeleton containing cyanobenzene, dicyanobenzene, or tricyanobenzene is further preferred.

[0222] As a compound formed by bonding an electron-donating skeleton and an electron-accepting skeleton as described above, an example is shown below, but it is not particularly limited to these. Furthermore, it is known from past literature that the compounds shown here emit delayed fluorescence.

[0223] [Chemical Formula 16]

[0224]

[0225] In addition, as a compound that emits delayed fluorescence, in addition to the compound formed by bonding an electron-donating skeleton and an electron-accepting skeleton, a compound represented by General Formula (6) or General Formula (7) is preferred.

[0226] [Chemical Formula 17]

[0227]

[0228] In General Formula (6) and General Formula (7), Ring Za, Ring Zb, and Ring Zc are each independently a substituted or unsubstituted aryl ring having 6 to 30 carbon atoms in the ring formation, or a substituted or unsubstituted heteroaryl ring having 5 to 30 carbon atoms in the ring formation. As an unsubstituted aryl ring having 6 to 30 carbon atoms in the ring formation, aromatic hydrocarbon rings such as benzene ring, naphthalene ring, phenanthrene ring, perylene ring, anthracene ring, and pyrene ring can be cited. Among these, from the viewpoint of ensuring solubility, a benzene ring is also preferred. In addition, as a heteroaryl ring having 5 to 30 carbon atoms in the ring formation, aromatic heteroaryl ring structures such as pyridine ring, quinoline ring, and phenanthroline ring can be cited. From the viewpoint of ease of obtaining raw materials or difficulty of synthesis, a pyridine ring is preferred. Ring Za, Ring Zb, and Ring Zc are preferably benzene rings. The reason is that the π-conjugated system of the compound represented by General Formula (6) or General Formula (7) is efficiently extended, and inverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, so the durability can be further improved.

[0229] In the above description and the following description, for example, a substituted or unsubstituted aryl having 6 to 40 carbon atoms also includes the carbon atoms contained in the substituents substituted in the aryl, and is 6 to 40, and the same applies to other substituents for which the carbon number is defined.

[0230] In the case of "substituted or unsubstituted", "unsubstituted" means that a hydrogen atom or a deuterium atom is substituted. In the compounds or their partial structures described below, the case of "substituted or unsubstituted" is the same as the above.

[0231] In General Formula (6), Z 1 and Z 2 are each independently an oxygen atom, NRa (a nitrogen atom having substituent Ra), or a sulfur atom. When Z 1 is NRa, Ra may bond to ring Za or ring Zb to form a ring. When Z 2 is NRa, Ra may bond to ring Za or ring Zc to form a ring.

[0232] E is a boron atom, a phosphorus atom, SiRa (a silicon atom having substituent Ra), or P═O.

[0233] In General Formula (7), E 1 and E 2 are each independently BRa (a boron atom having substituent Ra), PRa (a phosphorus atom having substituent Ra), SiRa2 (a silicon atom having two substituents Ra), P(═O)Ra2 (a phosphine oxide having two substituents Ra), or P(═S)Ra2 (a phosphine sulfide having two substituents Ra), S(═O), or S(═O)2. When E 1 is BRa, PRa, SiRa2, P(═O)Ra2, or P(═S)Ra2, Ra may bond to ring Za or ring Zb to form a ring. When E 2 is BRa, PRa, SiRa2, P(═O)Ra2, or P(═S)Ra2, Ra may bond to ring Za or ring Zc to form a ring.

[0234] Ra is each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group.

[0235] Ra is preferably a group having 6 to 40 carbon atoms including substituents. Ra is more preferably a substituted or unsubstituted aryl group. Examples of the substituted or unsubstituted aryl group include a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthrenyl group, etc., and a substituted or unsubstituted phenyl group is more preferable.

[0236] Z 1 and Z 2 are preferably an oxygen atom or NRa. The reason is that the π-conjugated system of the compound represented by General Formula (6) is extended with good efficiency, and reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, so the durability can be further improved.

[0237] E is preferably a boron atom, E 1 and E 2Preferably BRa. The reason is that the π-conjugated system of the compound represented by the general formula (6) is efficiently extended, and reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, so the durability can be further improved.

[0238] In all of the above groups, hydrogen may be deuterium. The same applies to the compounds or their partial structures described below.

[0239] In all of the above groups, when substituted, the substituents are alkyl, cycloalkyl, heterocyclic group, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl, hydroxy, mercapto, alkoxy, alkylthio, aryl ether group, aryl thioether group, halogen, cyano, aldehyde group, carbonyl group, carboxyl group, oxycarbonyl group, amide group, sulfonyl group, sulfonate group, sulfonamide group, amino group, nitro group, silyl group, siloxanyl group, boron group or phosphine oxide group. In addition, these substituents may be further substituted by the above substituents.

[0240] The compound represented by the general formula (6) or the general formula (7) is, for example, a molecule in which the HOMO orbital and the LUMO orbital can be separated by the multiple resonance effect by most preferably arranging the electron-donating amine nitrogen atom and the electron-accepting boron atom as described in the literature "Advanced Materials (Adv. Mater.,)" 2016, 28, 2777-2781. From the viewpoint of significantly separating the HOMO orbital and the LUMO orbital and making the singlet excited state and the triplet excited state closer to each other and easily emitting delayed fluorescence, it is preferred that E is a boron atom with strong electron-accepting property and Z 1 and Z 2 are both groups with strong electron-donating property, that is, NRa.

[0241] In addition, due to the multiple resonance effect, the emission spectrum of the compound represented by the general formula (6) or the general formula (7) is sharper than that of the compound formed by bonding the electron-donating skeleton and the electron-accepting skeleton, and high-color-purity emission can be obtained. That is, the compound represented by the general formula (6) or the general formula (7) is advantageous for improving the color gamut of the display, so it is preferred. In addition, for the compound represented by the general formula (6) or the general formula (7), since the rings Za, Zb, and Zc mainly exist around the E atom in the general formula (6) or the general formula (7) where the LUMO orbital is locally present, the LUMO orbital can be delocalized from the E atom to each ring. By delocalizing the LUMO orbital, the multiple resonance effect acts efficiently, so emission with higher color purity can be obtained.

[0242] Furthermore, it is more preferably a structure in which Ra of the general formula (6) or the general formula (7) is bonded to at least one of the rings Za, Zb, and Zc. The reason is that by bonding Ra to at least one of the rings Za, Zb, and Zc, E in the general formula (6) or E in the general formula (7)1 and E 2 The three-dimensional protection effect of is further improved, and it is expected that the effect of suppressing the decrease in the fluorescence quantum yield will be further improved.

[0243] An example of the compound represented by the general formula (6) or the general formula (7) is shown below, but it is not particularly limited to these.

[0244] [Chemical formula 18]

[0245]

[0246] <Binder resin in the color conversion layer (A) and the color conversion layer (B)>

[0247] In the color conversion sheet of the present invention, the color conversion layer (A) and the color conversion layer (B) preferably contain a binder resin in addition to the light-emitting material. As the binder resin, materials excellent in moldability, transparency, heat resistance, etc. can be preferably used. Examples of the binder resin include, for example: photocurable resist materials having reactive vinyl such as acrylic, methacrylic, polyvinyl cinnamate, and cyclo rubber, epoxy resins, silicone resins (including organopolysiloxane hardened products (crosslinked products) such as silicone rubber and silicone gel), urea resins, fluororesins, polycarbonate resins, acrylic resins, urethane resins, melamine resins, polyethylene resins, polyamide resins, phenol resins, polyvinyl alcohol resins, polyvinyl butyral resins, cellulose resins, aliphatic ester resins, aromatic ester resins, aliphatic polyolefin resins, aromatic polyolefin resins, and other known binder resins. In addition, as the binder resin, mixtures or copolymers of these resins can also be used. For example, a copolymer of methyl methacrylate and an aliphatic polyolefin resin can be cited. By appropriately designing these resins, a binder resin useful for the color conversion sheet of the embodiment of the present invention can be obtained.

[0248] Among these resins, from the viewpoints of transparency and dispersibility of the organic light-emitting material, any one of a binder resin, an acrylic resin, a copolymer resin containing an acrylate or methacrylate moiety, a polyester resin, an aliphatic polyolefin resin, and a copolymer thereof is preferred.

[0249] <Other additives>

[0250] In addition to adding a binder resin and a light-emitting material, the color conversion sheet of the present invention can also add fillers, antioxidants, processing and heat stabilizers, light resistance stabilizers such as ultraviolet absorbers, dispersants or leveling agents for coating film stabilization, plasticizers, crosslinking agents such as epoxy compounds, hardeners such as amine - acid anhydride - imidazole, pigments, adhesion aids such as silane coupling agents as surface modifiers of the sheet, and the like.

[0251] As the filler, examples include fine particles such as fumed silica, glass powder, and quartz powder; titanium oxide, zirconium oxide, barium titanate, zinc oxide, and silicone fine particles, but there is no particular limitation. In addition, these fillers may be used alone or in combination of multiple kinds.

[0252] As the antioxidant, examples include phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol and 2,6-di-tert-butyl-4-ethylphenol, but there is no particular limitation. In addition, these antioxidants may be used alone or in combination of multiple kinds.

[0253] As the processing and heat stabilizer, examples include phosphorus-based stabilizers such as tributyl phosphite, tricyclohexyl phosphite, triethyl phosphine, and diphenylbutyl phosphine, but there is no particular limitation. In addition, these stabilizers may be used alone or in combination of multiple kinds.

[0254] As the light fastness stabilizer, for example, examples include benzotriazoles such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, but there is no particular limitation. In addition, these light fastness stabilizers may be used alone or in combination of multiple kinds.

[0255] The content of these additives in the color-changing sheet of the present invention also depends on the molar extinction coefficient of the compound, the fluorescence quantum yield and the absorption intensity at the excitation wavelength, and the thickness or transmittance of the produced sheet, and is usually 1.0×10 -3 parts by mass or more and 30 parts by mass or less, more preferably 1.0×10 -2 parts by mass or more and 15 parts by mass or less, and particularly preferably 1.0×10 -1 parts by mass or more and 10 parts by mass or less.

[0256] <Solvent>

[0257] The color conversion sheet of the present invention may also contain a solvent. The solvent is not particularly limited as long as it can adjust the viscosity of the resin in a flowing state and does not have an excessive impact on the luminescence and durability of the luminescent substance. For example, water, 2-propanol, ethanol, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, hexane, heptane, acetone, methyl acetate, ethyl acetate, butyl acetate, propyl acetate, isopropyl acetate, terpineol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol), methyl cellosolve, ethyl cellosolve, butyl carbitol, butyl carbitol acetate, 1-methoxy-2-propanol, propylene glycol monomethyl ether acetate, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, etc. may be mentioned, and two or more of these solvents may be used in combination. Among these solvents, in particular, in terms of not affecting the deterioration of the compound represented by the general formula (1) and having less residual solvent after drying, toluene and ethyl acetate can be preferably used.

[0258] <Method for producing color conversion sheet>

[0259] Hereinafter, an example of the method for producing the color conversion sheet of the present invention will be described. In the method for producing the color conversion sheet, first, a composition for forming a color conversion layer is produced in the following manner.

[0260] Mix the above-mentioned luminescent material, binder resin, solvent, etc. in a predetermined amount. After mixing the above components so as to have a predetermined composition, they are uniformly mixed and dispersed using a stirring / kneading machine such as a homogenizer, a rotary-revolution mixer, a three-roll mill, a ball mill, a planetary ball mill, a bead mill, etc., thereby obtaining a color conversion composition. After or during the mixing and dispersion, it is also preferable to perform an operation of degassing under vacuum or reduced pressure. In addition, a specific component may be mixed in advance or a treatment such as aging may be performed. The solvent may be removed by an evaporator to obtain a desired solid component concentration.

[0261] In the present invention, as a representative structural example of the color conversion sheet, the above-mentioned Figure 1 may be mentioned. Further, in order to prevent the color conversion layer from deteriorating due to oxygen, moisture, or heat, a barrier layer 6 may be further provided as Figure 3 shown.

[0262] The thickness of the color conversion sheet is not particularly limited, and it is preferably 1 μm to 5000 μm in total for all layers. By having a thickness of 1 μm or more, sufficient film strength can be ensured, and problems such as film breakage are less likely to occur. By having a thickness of 5000 μm or less, a sheet with excellent operability can be obtained. The thickness is more preferably 10 μm to 1000 μm, further preferably 15 μm to 500 μm, and particularly preferably 30 μm to 300 μm.

[0263] The film thickness related to the color-changing sheet of the present invention refers to the film thickness (average film thickness) measured by Method A of the thickness measurement method using mechanical scanning in Japanese Industrial Standards (JIS) K7130 (1999) Plastics - Films and Sheets - Methods of thickness measurement.

[0264] <Substrate layer>

[0265] As the substrate layer, known metals, films, glasses, ceramics, papers, etc. can be used without particular limitation. Specifically, examples include: metal plates or foils such as aluminum (including aluminum alloys), zinc, copper, and iron; cellulose acetate, polyethylene terephthalate (PET), polyethylene, polyester, polyamide, polyimide, polyphenylene sulfide, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, aramid, silicone, polyolefin, thermoplastic fluororesin, copolymer of tetrafluoroethylene and ethylene (ethylene - tetrafluoroethylene, ETFE); films of plastics containing α - polyolefin resin, polycaprolactone resin, acrylic resin, silicone resin, and copolymer resins of these resins and ethylene; papers laminated with the plastic film, or papers coated with the plastic, papers laminated or vapor - deposited with the metal, plastic films laminated or vapor - deposited with the metal, etc. In addition, when the substrate is a metal plate, surface plating treatments such as chromium - based or nickel - based treatments or ceramic treatments can also be applied.

[0266] Among these, in terms of the ease of manufacturing the color - changing sheet or the ease of forming the color - changing sheet, glass or resin films can be preferably used. In addition, a film with high strength is preferred so as to have no concerns about breakage, etc. when processing the film - like substrate. In terms of these required characteristics or economy, a resin film is preferred. Among these, in terms of economy and operability, plastic films selected from the group consisting of PET, polyphenylene sulfide, polycarbonate, and polypropylene are preferred. In addition, when drying the color - changing sheet or press - forming the color - changing sheet at a high temperature of 200 °C or higher by an extruder, a polyimide film is preferred in terms of heat resistance. In terms of the ease of peeling of the sheet, the surface of the substrate layer can also be pre - treated with a release treatment.

[0267] The thickness of the substrate layer is not particularly limited. As the lower limit, it is preferably 5 μm or more, more preferably 25 μm or more, and still more preferably 38 μm or more. In addition, as the upper limit, it is preferably 5000 μm or less, more preferably 3000 μm or less.

[0268] <Color - changing layer>

[0269] Next, an example of the manufacturing method of the color conversion layer contained in the color conversion sheet of the present invention will be described. The color conversion composition produced by the above method is coated on a substrate and dried. Coating can be carried out by a reverse roll coater, a blade coater, a slot die coater, a direct gravure coater, an offset gravure coater, a kiss coater, a natural roll coater, an air knife coater, a roll blade coater, a two-stream coater, a rod coater, a wire bar coater, an applicator, a dip coater, a curtain coater, a spin coater, a knife coater, etc. In order to obtain the film thickness uniformity of the color conversion layer, it is preferably coated by a slot die coater or a dip coater.

[0270] Drying of the color conversion layer can be carried out using a general heating device such as a hot air dryer or an infrared dryer. In the above case, the heating conditions are usually 40°C to 250°C and 1 minute to 5 hours, preferably 60°C to 200°C and 2 minutes to 4 hours. In addition, step cure or other staged heat hardening can also be carried out.

[0271] After manufacturing the color conversion sheet, the substrate can also be changed as needed. In the above case, as a simple method, methods such as reattachment using a hot plate or using a vacuum laminator or a dry film laminator can be cited, but it is not limited to these methods.

[0272] The thickness of the color conversion layer is not particularly limited, preferably 1 μm to 1000 μm, more preferably 10 μm to 1000 μm. By having a thickness of 1 μm or more, sufficient film strength can be ensured, and problems such as film breakage are not likely to occur. By having a thickness of 5000 μm or less, a sheet with excellent operability can be obtained. The thickness is more preferably 10 μm to 100 μm, further preferably 15 μm to 100 μm, and particularly preferably 30 μm to 100 μm.

[0273] <Barrier layer>

[0274] The barrier layer can be suitably used when imparting gas barrier properties to the color conversion layer. Specifically, examples of the barrier layer include 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; or mixtures thereof, or metal oxide films or metal nitride films in which other elements are added to these substances; or 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. In addition, examples of the film having a moisture barrier function include films containing various resins such as polyethylene, polypropylene, nylon, polyvinylidene chloride, copolymers of vinylidene chloride and vinyl chloride, copolymers of vinylidene chloride and acrylonitrile, fluorine resins, and polyvinyl alcohol resins such as saponified vinyl acetate.

[0275] The barrier layer can be provided on both sides of the color conversion layer or only on one side.

[0276] In addition, according to the functions required for the color conversion sheet, an auxiliary layer having functions such as a light extraction function, an antireflection function, an antiglare function, an antireflection antiglare function, a hard coat function (abrasion resistance function), an antistatic function, an antifouling function, an electromagnetic wave shielding function, an infrared cut-off function, an ultraviolet cut-off function, a polarization function, and a color tone adjustment function can be further provided.

[0277] <Excitation light>

[0278] As long as the type of the light source of the excitation light is a light source that emits light in the wavelength region that can be absorbed by the luminescent material, any one can be used. For example, any light source such as a hot cathode tube or a cold cathode tube, a fluorescent light source such as an inorganic EL, an organic electroluminescent element light source, an LED light source, or an incandescent light source can be utilized in principle. Among them, an LED is a preferred light source. In a display or a lighting device, a blue LED having excitation light in the wavelength range of 400 nm to 500 nm is a further preferred light source in terms of improving the color purity of blue light. If the wavelength range of the excitation light is on the longer wavelength side than this, there is a lack of blue light, so white light cannot be formed. In addition, if the wavelength range of the excitation light is on the shorter wavelength side than this, organic compounds such as the luminescent material or the resin are liable to be photo-degraded, so it is not good.

[0279] The excitation light can have one emission peak or two or more emission peaks. In order to improve the color purity, it is preferably to have one emission peak. In addition, a plurality of excitation light sources having different types of emission peaks can be arbitrarily combined and used.

[0280] A color conversion sheet according to another embodiment of the present invention is a color conversion sheet that converts incident light into light having a wavelength different from that of the incident light. The color conversion sheet includes at least a color conversion layer, a resin layer, and a substrate in this order. The color conversion layer contains a luminescent material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm, and a luminescent material (b) that emits light having a peak wavelength observed in a region of 580 nm or more and 750 nm or less. The haze value of the color conversion sheet is 20% or more and 90% or less. When the refractive index of the color conversion layer is set to n A , the refractive index of the resin layer is set to n B , and the refractive index of the substrate is set to n C , n A > n B and n B < n C . For n A > n B and n B < n C , the resin layer is also referred to as a low refractive index layer.

[0281] A structural example of the color conversion sheet of the above embodiment is illustrated in Figure 4 . The color conversion sheet 5 includes a substrate layer 1, and a color conversion layer 7 and a resin layer 3 are laminated on the substrate layer 1. It may also have a structure in which a substrate layer 1 is further disposed on the resin layer 3, and the color conversion layer 7 and the resin layer 3 are sandwiched by the substrate layer 1. The resin layer 3 is preferably disposed at a position opposite to the light source side when viewed from the color conversion layer 7. Further, when the refractive index of the color conversion layer is set to n A , the refractive index of the resin layer is set to n B , and the refractive index of the substrate is set to n C , it is necessary that n A > n B and n B < n C . By having the resin layer at the above position, light emitted from the light source side is reflected at the interface between the color conversion layer and the resin layer. Therefore, light leakage to the outside of each layer can be suppressed, and thus the color conversion efficiency can be further improved, and good durability can be obtained.

[0282] The color conversion layer 7 of the above embodiment contains both a luminescent material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm, and a luminescent material (b) that emits light having a peak wavelength observed in a region of 580 nm or more and 750 nm or less. The color conversion layer 7 preferably contains a binder resin in addition to the luminescent material. In addition, in order to control the haze value, the color conversion layer 7 may contain scattering particles.

[0283] Furthermore, the haze value, scattering particles, resin layer, light-emitting material, adhesive resin, substrate layer, barrier layer, and manufacturing method of the color conversion sheet are the same as those of the above-described embodiment.

[0284] <Light Source Unit>

[0285] The light source unit of the present invention contains at least a light source and a color conversion sheet. In the light source unit of the present invention, it is preferably arranged in the order of light source, color conversion layer (B), resin layer, and color conversion layer (A). In the light source unit, in addition to containing a light source and a color conversion sheet, other optical sheets may also be contained. As the optical sheet, a prism sheet, a polarization reflective film, a diffusion sheet, etc. may be mentioned. As a representative structural example, there is the following structure: as Figure 5 shown, the substrate 8, the reflective layer 9, and the light source 10 are laminated, the color conversion sheet 5 of the present invention is arranged between the diffusion plate 11 and the prism sheet 12, and further, a polarization reflective film 13 is arranged on the surface of the prism sheet 12 opposite to the light source. From the viewpoints of thinning, productivity, and light durability, the number of optical sheets contained above the color conversion sheet of the present invention is preferably two or less. Here, the so-called "above the color conversion sheet" means the side opposite to the light source with respect to the color conversion sheet. By having two or less optical sheets, light reflection can be suppressed, so the excitation times of the light-emitting material can be reduced, and thus a decrease in durability can be prevented. Figure 5 The light source of [] is a so-called direct-lit type structure, but the arrangement of the light source is not particularly limited. When the color conversion sheet is contained in the light source unit, regarding the arrangement method of the light source and the color conversion sheet, in addition to the structure of the above-described order, there is no particular limitation, and a structure in which the light source and the color conversion sheet are in close contact may be adopted, or a remote phosphor form in which the light source and the color conversion sheet are separated may be adopted. In addition, for the purpose of improving color purity, a structure containing a color filter may also be adopted.

[0286] As described above, the excitation light in the range of 400 nm to 500 nm has a small excitation energy and can prevent the decomposition of the light-emitting material. Therefore, the light source is preferably a light-emitting diode having a maximum emission in the range of 400 nm to 500 nm.

[0287] The light source unit of the present invention can be used for applications such as displays, lighting devices, interiors, signs, and billboards. In particular, it can be preferably used for displays or lighting devices.

[0288] Examples

[0289] Hereinafter, examples will be given to illustrate the present invention, but the present invention is not limited by these examples.

[0290] <Measurement of Haze and Total Light Transmittance>

[0291] The haze and total light transmittance of the color conversion films, color conversion layer (A), and color conversion layer (B) produced in the examples and comparative examples were measured using NDH7000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with ASTM D 1003 (2013). The number of measurements was set to one for each.

[0292] <Measurement of refractive index>

[0293] The refractive index (n A1 , n A2 , n B , n C , n D1 , n D2 ) of each layer was obtained by measuring the refractive index of the resin film formed by separately coating the composition for each layer on a PET film. On "Lumirror" U48 (manufactured by Toray Industries, Inc., thickness 50 μm), using a Baker type applicator, the composition for each layer was coated so that the average film thickness became 2 μm, and dried by heating at 100 °C for 20 minutes to form a resin film for measurement. The refractive index of the formed resin film for light with a wavelength of 589.3 nm was measured using a reflection spectrometer FE-3000 (manufactured by Otsuka Electronics Co., Ltd.).

[0294] <Measurement of color conversion characteristics>

[0295] On a light-emitting device equipped with a blue LED (manufactured by USHIO EPITEX; model SMBB450H-1100, emission peak wavelength: 450 nm), each color conversion film to be evaluated was set in the order of light source, color conversion layer (B), resin layer, and color conversion layer (A). A current of 100 mA was passed through the light-emitting device to turn on the blue LED, and a spectro-radiance meter (CS-1000, manufactured by Konica Minolta) was used to measure the emission spectrum, emission intensity, and chromaticity at the peak wavelength. Furthermore, the distance between each color conversion film and the blue LED element was set to 3 cm.

[0296] <Evaluation of in-plane uniformity>

[0297] Disassemble the liquid crystal monitor (SW2700PT) manufactured by BenQ Corporation, insert the color conversion films fabricated in the following Examples and Comparative Examples to replace the built-in color conversion film, and then assemble it in its original state. The structure of the backlight unit at this time is "reflective film / light guide plate / diffusion sheet / color conversion film / prismatic sheet / polarizing reflective film". Measure the 9-point color coordinates u' and v' using a spectro-radiance meter (CS-1000, manufactured by Konica Minolta), and calculate the in-plane deviation Δu'v' through the following formula.

[0298] Δu' = u'(max) - u'(min.)

[0299] Δv' = v'(max) - v'(min.)

[0300] Δu'v' = {(Δu') 2 +(Δv') 2} 1 / 2

[0301] If Δu'v' is 0.02 or less, it is considered good; if it is 0.015 or less, it is considered extremely good.

[0302] <Light durability test>

[0303] On a light-emitting device equipped with a blue LED (manufactured by USHIO EPITEX; model SMBB450H-1100, peak emission wavelength: 450 nm), arrange the respective color conversion films to be evaluated in the order of light source / color conversion layer (B) / resin layer / color conversion layer (A). Pass a current of 100 mA through the light-emitting device to turn on the blue LED, and measure the peak intensity at the wavelength of the light converted by the color conversion using a spectro-radiance meter (CS-1000, manufactured by Konica Minolta). Furthermore, set the distance between each color conversion film and the blue LED element to 3 cm. Then, continuously irradiate the light from the blue LED element in an environment of 50 °C and 80% RH, and observe the time until the luminescence intensity of the phosphor decreases by 10% from the initial value, thereby evaluating the durability of the color conversion film. If the time until the luminescence intensity of the phosphor decreases by 10% from the initial value is 200 hours or more, it is considered good; if it is 400 hours or more, it is considered extremely good.

[0304] <Luminescent material>

[0305] In the following Examples and Comparative Examples, Compound G-1, Compound G-3, and Compound R-1 are the compounds shown below.

[0306] [Chemical formula 19]

[0307]

[0308] [Chemical formula 20]

[0309]

[0310] Compound G-1 (emission peak wavelength: 515 nm) and compound G-3 (emission peak wavelength: 527 nm) are synthesized by a known method.

[0311] G-2: Quantum dots (product number 776793) manufactured by Sigma-Aldrich (emission peak wavelength: 560 nm).

[0312] Compound R-1 (emission peak wavelength: 629.5 nm) is synthesized by a known method.

[0313] Scattering particles S-1, S-2, S-3, and S-4 are the materials shown below.

[0314] S-1: JR-301 (titanium dioxide particles manufactured by Tayca Corporation, average particle size 300 nm)

[0315] S-2: AA-07 (aluminum oxide particles manufactured by Sumitomo Chemical Co., Ltd., average particle size 830 nm)

[0316] S-3: SO-E6 (silica particles manufactured by Admatechs Co., Ltd., average particle size 2000 μm)

[0317] S-4: KMP-706 (silicone resin particles manufactured by Shin-Etsu Chemical Co., Ltd., average particle size 2000 nm)

[0318] (Example 1)

[0319] 100 parts by weight of acrylic resin Olycox KC-7000 manufactured by Kyoeisha Chemical Co., Ltd. as a resin, 0.4 parts by weight of G-1 as a light-emitting material, 0.3 parts by weight of S-1 as a scattering particle, and 300 parts by weight of toluene as a solvent are mixed, and then using a planetary stirring / degassing device "Mazerustar" (registered trademark) KK-400 manufactured by Kurabo Industries Ltd., stirred / degassed at 1000 rpm for 20 minutes to obtain a resin composition for producing a color-changing layer (A).

[0320] Similarly, using silicone resin (KR-114B manufactured by Shin-Etsu Chemical Co., Ltd.) as the resin, 200 parts by weight of heptane as the solvent was mixed with 100 parts by weight of the resin, and then using a planetary stirring / defoaming device "Mazerustar" (registered trademark) KK-400 (manufactured by Kurabo Industries Ltd.), it was stirred / defoamed at 300 rpm for 20 minutes to obtain a resin composition for forming a resin layer.

[0321] Similarly, 100 parts by weight of the same resin as the resin liquid for forming the color-changing layer (A), 0.08 parts by weight of compound R-1 as the luminescent material, 0.3 parts by weight of S-1 as the scattering particles, and 200 parts by weight of toluene as the solvent were mixed, and then using a planetary stirring / defoaming device "Mazerustar" (registered trademark) KK-400 (manufactured by Kurabo Industries Ltd.), it was stirred / defoamed at 300 rpm for 20 minutes to obtain a resin composition for forming the color-changing layer (B).

[0322] Next, using a slit die coater, the resin composition for forming the color-changing layer (A) was coated on a substrate of "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., thickness 50 μm), and heated at 120°C for 20 minutes and dried to form a color-changing layer (A) with an average film thickness of 18 μm.

[0323] Similarly, using a slit die coater, the resin composition for forming the resin layer was coated on the color-changing layer (A), and heated at 120°C for 20 minutes and dried to form a resin layer with an average film thickness of 10 μm.

[0324] Similarly, using a slit die coater, the resin composition for forming the color-changing layer (B) was coated on a substrate of "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., thickness 50 μm), and heated at 120°C for 20 minutes and dried to form a color-changing layer (B) with an average film thickness of 18 μm.

[0325] Next, the two units were heated and laminated such that the resin layer was in direct contact with the color-changing layer (B), thereby fabricating a color-changing sheet having a structure of "substrate / color-changing layer (A) / resin layer / color-changing layer (B) / substrate".

[0326] Using the fabricated color-changing sheet, the refractive index of each layer was measured by the above method. The results are shown in Table 1.

[0327] (Examples 2 to 8, Examples 17, 18, Comparative Examples 1 to 3)

[0328] Except for changing the composition as shown in Tables 1 and 2, a color conversion sheet was produced by the same operation as in Example 1 and evaluated. In Example 17, the resin of the resin layer was changed to polyester "Vylon" (registered trademark) 270 manufactured by Toyobo Co., Ltd. In Comparative Example 3, the resin of the resin layer was changed to acrylic resin Olycox KC-7000 manufactured by Koei Chemical Co., Ltd. The results are shown in Tables 1 and 2.

[0329] From the comparison between Example 1 and Comparative Example 1, compared with Comparative Example 1 with a haze value of less than 20%, the in-plane uniformity of Example 1 with a haze value of 20% or more was significantly improved.

[0330] In addition, from the comparison between Examples 1 to 5, it was found that the larger the haze value, the better the in-plane uniformity. Among them, as shown in Comparative Example 2, it was found that when the haze value exceeded 90%, the in-plane uniformity was good, but the light durability decreased significantly. The in-plane uniformity and durability of Examples 3, 4, and 8 were particularly good.

[0331] From the comparison between Example 7 and Example 4, it was found that as the luminescent material of the color conversion layer (A), G-1 had better light durability than G-2.

[0332] From the comparison between Example 18 and Example 4, it was found that as the luminescent material of the color conversion layer (A), G-1 and G-3 had the same light durability.

[0333] From the comparison between Example 17 and Example 4, it was found that compared with the case where the refractive index n B was less than the refractive index n A1 of the color conversion layer (A) and the refractive index n A2 of the color conversion layer (B), when the refractive index n B of the resin layer was greater than the refractive index n A1 of the color conversion layer (A) and the refractive index n A2 of the color conversion layer (B), the light durability decreased.

[0334] From the comparison between Example 17 and Comparative Example 3, it was found that compared with the case where the refractive index n B of the resin layer was greater than the refractive index n A1 of the color conversion layer (A) and the refractive index n A2 of the color conversion layer (B), when the refractive index n B of the resin layer was the same as the refractive index n A1 of the color conversion layer (A) and the refractive index n A2 of the color conversion layer (B), the light durability decreased.

[0335]

[0336] [Table 2]

[0337]

[0338] <Calculation of gamut area ratio>

[0339] The liquid crystal monitor (SW2700PT) manufactured by BenQ Corporation was disassembled, and the color conversion sheet produced in the following-described embodiment was inserted to replace the built-in color conversion sheet, and then it was assembled in the original state. The structure of the backlight unit at this time was "reflective film / light guide plate / diffusion sheet / color conversion sheet / prismatic sheet / polarizing reflective film". Regarding the respective color coordinates in the (X, Y) color space when the obtained monitor displays monochromatic colors of blue, green, and red, they were measured using a spectro-radiance meter (CS-1000, manufactured by Konica Minolta). The area of the gamut was calculated based on the obtained three color coordinates, and the area ratio of the DCI-P3 standard with respect to the gamut area was calculated. If the area ratio is 100% or more, it is good, and if it is 105% or more, it is extremely good.

[0340] <Relative luminance>

[0341] The luminance of the white light after color conversion in Example 3 was set to 100, and the luminance of the following-described examples was compared. The relative luminance (%) is the relative luminance based on Example 3.

[0342] (Example 9)

[0343] A color conversion sheet was produced by the same operation as in Example 3, except that the scattering particles in the color conversion layer (A) were 1.3 parts by weight and no scattering particles were added to the color conversion layer (B). Using the produced color conversion sheet, the color characteristics were measured by the said method, and as a result, the emission peak of green was 527 nm and the emission peak of red was 637 nm. The gamut area ratio was calculated by the said method, and the result was 105%. In addition, the relative luminance was calculated by the said method, and the result was 97%. The haze value and the refractive index of each layer were measured by the said method. The results are shown in Table 3.

[0344] (Example 10)

[0345] A color conversion sheet was produced in the same manner as in Example 3, except that the scattering particles in the color conversion layer (A) were 2 parts by weight and no scattering particles were added to the color conversion layer (B). Using the produced color conversion sheet, the color characteristics were measured by the method described above. As a result, the emission peak of green was 525 nm and the emission peak of red was 639 nm. The gamut area ratio was calculated by the method described above, and the result was 108%. In addition, the relative luminance was calculated by the method described above, and the result was 93%. The haze value and the refractive index of each layer were measured by the method described above. The results are shown in Table 3.

[0346] (Example 11)

[0347] A color conversion sheet was produced in the same manner as in Example 3, except that no scattering particles were added to the color conversion layer (A) and the scattering particles in the color conversion layer (B) were 1.3 parts by weight. Using the produced color conversion sheet, the color characteristics were measured by the method described above. As a result, the emission peak of green was 532 nm and the emission peak of red was 634 nm. The gamut area ratio was calculated by the method described above, and the result was 98%. In addition, the relative luminance was calculated by the method described above, and the result was 108%. The haze value and the refractive index of each layer were measured by the method described above. The results are shown in Table 3.

[0348] (Example 12)

[0349] A color conversion sheet was produced in the same manner as in Example 3, except that no scattering particles were added to the color conversion layer (A) and the scattering particles in the color conversion layer (B) were 2 parts by weight. Using the produced color conversion sheet, the color characteristics were measured by the method described above. As a result, the emission peak of green was 534 nm and the emission peak of red was 632 nm. The gamut area ratio was calculated by the method described above, and the result was 95%. In addition, the relative luminance was calculated by the method described above, and the result was 110%. The haze value and the refractive index of each layer were measured by the method described above. The results are shown in Table 3.

[0350] From the comparison between Example 9, Example 10 and Example 11, Example 12, it can be seen that the gamut area is increased compared with the case where only the color conversion layer (A) contains scattering particles and the case where only the color conversion layer (B) contains scattering particles.

[0351] In addition, from the comparison between Example 11, Example 12 and Example 3, Example 9, Example 10, it can be seen that the luminance is increased compared with the case where only the color conversion layer (B) contains scattering particles, the case where both the color conversion layer (A) and the color conversion layer (B) contain scattering particles, or the case where only the color conversion layer (A) contains scattering particles.

[0352] (Comparative Example 7)

[0353] A color conversion sheet was produced in the same manner as in Example 3, except that the scattering particles in the color conversion layer (A) were 8 parts by weight and no scattering particles were added to the color conversion layer (B). Using the produced color conversion sheet, the color characteristics were measured by the said method. As a result, the emission peak of green was 523 nm and the emission peak of red was 641 nm. The color gamut area ratio was calculated by the said method, and the result was 108%. In addition, the relative luminance was calculated by the said method, and the result was 85%. The haze value and the refractive index of each layer were measured by the said method. The results are shown in Table 3.

[0354] (Comparative Example 8)

[0355] A color conversion sheet was produced in the same manner as in Example 3, except that no scattering particles were added to the color conversion layer (A) and the scattering particles in the color conversion layer (B) were 8 parts by weight. Using the produced color conversion sheet, the color characteristics were measured by the said method. As a result, the emission peak of green was 536 nm and the emission peak of red was 630 nm. The color gamut area ratio was calculated by the said method, and the result was 94%. In addition, the relative luminance was calculated by the said method, and the result was 100%. The haze value and the refractive index of each layer were measured by the said method. The results are shown in Table 3.

[0356] From the comparison between Example 9, Example 10 and Comparative Example 7, and the comparison between Example 11, Example 12 and Comparative Example 8, it can be seen that when the content of the particles is too high and the haze exceeds 90%, the luminance will decrease significantly.

[0357] [Table 3]

[0358]

[0359] (Example 13)

[0360] 100 parts by weight of acrylic resin Olycox KC-7000 manufactured by Synergy Chemical Co., Ltd. as the resin, 0.4 parts by weight of G-1 as the luminescent material (a), 0.01 parts by weight of R-1 as the luminescent material (b), 0.6 parts by weight of S-1 as the scattering particles, and 300 parts by weight of toluene as the solvent were mixed, and then using a planetary stirring / degassing device "Mazerustar" (registered trademark) KK-400 (manufactured by Kurabo Industries Ltd.), stirred / degassed at 1000 rpm for 20 minutes to obtain a resin composition for producing a color conversion layer.

[0361] A resin liquid composition for producing a resin layer was obtained in the same manner as in Example 1.

[0362] Next, using a slot die coater, a resin composition for forming a color conversion layer was coated on a substrate of "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., thickness 50 μm), and heated at 120°C for 20 minutes and dried to form a color conversion layer with an average film thickness of 18 μm.

[0363] In the same manner as in Example 1, a resin layer with an average film thickness of 10 μm was formed on the color conversion layer.

[0364] Next, by thermally laminating "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., thickness 50 μm) on the resin layer, a color conversion sheet having a structure of "substrate / color conversion layer / resin layer / substrate" was produced.

[0365] Using the produced color conversion sheet, the refractive index of each layer was measured by the above method. The results are shown in Table 4.

[0366] (Examples 14 to 16, Comparative Examples 4 to 6)

[0367] Except for changing the composition as shown in Table 4, color conversion sheets were produced by the same operations as in Example 13 and evaluated. In Comparative Example 6, the resin of the resin layer was changed to a polyester of "Vylon" (registered trademark) 270 manufactured by Toyobo Co., Ltd. The results are shown in Table 4.

[0368] From the comparison between Example 13 and Comparative Example 4, compared with Comparative Example 4 with a haze value of less than 20%, the in-plane uniformity of Example 13 with a haze value of 20% or more was significantly improved.

[0369] In addition, from the comparison between Examples 13 to 16, it was found that the larger the haze value, the better the in-plane uniformity. Among them, as shown in Comparative Example 5, it was found that when the haze value exceeded 90%, the in-plane uniformity was good, but the light durability decreased significantly. The in-plane uniformity and durability of Examples 14 and 15 were particularly good.

[0370] From the comparison between Comparative Example 6 and Example 15, it was found that when the refractive index n B of the resin layer was the same as or larger than the refractive index n A of the color conversion layer and the refractive index n C of the substrate layer, the light durability decreased significantly.

[0371]

[0372] (Examples 19 to 21)

[0373] Except for changing the composition as shown in Table 5, a color conversion sheet was produced by the same operation as in Example 11 and evaluated. The scattering particles in Example 19, Example 20, and Example 21 were changed to S-2, S-3, and S-4, respectively. The results are shown in Table 5.

[0374] From the comparison between Example 11 and Examples 19 to 21, it can be seen that when the absolute value of the difference between the refractive index n A2 of the color conversion layer and the refractive index n D2 of the scattering particles is within the above range, the total light transmittance increases, and a color conversion sheet with higher brightness can be obtained.

[0375] [Table 5]

[0376]

Claims

1. A color conversion sheet that converts incident light into light having a wavelength different from that of the incident light. The color conversion sheet contains at least a color conversion layer, a resin layer, and a substrate in this order. The color conversion layer, the resin layer, and the substrate are directly adjacent to each other. The color conversion layer contains a luminescent material (a) that emits light having a peak wavelength observed in a region of 500 nm or more and less than 580 nm, and a luminescent material (b) that emits light having a peak wavelength observed in a region of 580 nm or more and 750 nm or less, and The haze value of the color conversion sheet is 20% or more and 90% or less. When the refractive index of the color conversion layer is set to n A , the refractive index of the resin layer is set to n B , and the refractive index of the substrate is set to n C , n A > n B and n B < n C .

2. The color conversion sheet according to claim 1, wherein the luminescent material (a) and / or the luminescent material (b) is an organic luminescent material.

3. The color conversion sheet according to claim 2, wherein the organic luminescent material contains a compound represented by the general formula (1). X is C-R 7 or N; R 1 ~R 9 may be the same or different and are each independently selected from hydrogen, alkyl, cycloalkyl, heterocyclic group, alkenyl, cycloalkenyl, alkynyl, hydroxy, mercapto, alkoxy, alkylthio, aryl ether group, aryl thioether group, aryl, heteroaryl, halogen, cyano, aldehyde group, carbonyl group, carboxyl group, oxycarbonyl group, carbamoyl group, amino group, nitro group, silyl group, siloxy group, boron group, phosphinyl group and a condensed ring and an aliphatic ring formed between adjacent substituents.

4. The color conversion sheet according to claim 1 or 2, wherein the haze value of the color conversion sheet is 50% or more and 75% or less.

5. The color conversion sheet according to claim 1 or 2, wherein the color conversion layer contains scattering particles.

6. The color conversion sheet according to claim 5, wherein the scattering particles contain titanium dioxide.

7. The color conversion sheet according to claim 5, wherein the average particle diameter of the scattering particles is 100 to 500 nm.

8. The color conversion sheet according to claim 1 or 2, wherein the resin layer contains a silicone resin.

9. A light source unit, comprising a light source and the color conversion sheet according to any one of claims 1 to 5.

10. The light source unit according to claim 9, wherein the light source is a light emitting diode having maximum emission in the range of 400 nm or more and 500 nm or less.

11. The light source unit according to claim 9, further comprising an optical sheet other than the color conversion sheet.

12. The light source unit according to claim 11, wherein the number of the optical sheets contained above the color conversion sheet is two or less.

13. A display device, comprising the light source unit according to any one of claims 9 to 12.

14. A lighting device, comprising the light source unit according to any one of claims 9 to 12.

Images