JP6679988B2 - Light wavelength conversion sheet, backlight device including the same, image display device, and method for manufacturing light wavelength conversion sheet - Google Patents

Description

  The present invention relates to a light wavelength conversion sheet, a backlight device including the light wavelength conversion sheet, an image display device, and a method for manufacturing the light wavelength conversion sheet.

  A transmissive image display device such as a liquid crystal display device is generally provided with a backlight device which is arranged on the back side of a transmissive image display panel such as a liquid crystal display panel and illuminates the transmissive image display panel. As a backlight device, an edge light type or a direct type backlight device is known.

  Currently, in order to improve color reproducibility, it is considered to arrange a light wavelength conversion sheet having a light wavelength conversion layer containing quantum dots and a binder resin on a light guide plate or a light source in a backlight device (for example, patents Reference 1). Quantum dots can absorb light and emit light of different wavelengths. The wavelength of light emitted by the quantum dots mainly depends on the particle size of the quantum dots. Therefore, in the backlight device in which the light wavelength conversion sheet is incorporated, various colors can be reproduced while using a light source that projects light in a single wavelength range. For example, when a light source that emits blue light is used, the light wavelength conversion sheet may absorb blue light and emit green light and red light. Since the backlight device incorporating such a light wavelength conversion sheet has excellent color purity, the image display device using this backlight device has excellent color reproducibility.

JP, 2015-111518, A

  In the light wavelength conversion sheet, the quantum dots may be deteriorated by water and oxygen, which may reduce the luminous efficiency.Therefore, a barrier film for suppressing the permeation of water and oxygen should be provided on both surfaces of the light wavelength conversion layer. It is provided. Since the barrier film is provided so as to sandwich the light wavelength conversion layer, the conventional light wavelength conversion sheet has a structure in which the barrier film, the light wavelength conversion layer, and the barrier film are laminated in this order.

  However, in a light wavelength conversion sheet including a barrier film, deterioration due to pinholes or cracks generated in the barrier film is likely to occur. If pinholes or cracks occur in the barrier film, moisture or oxygen may enter from there and some quantum dots may deteriorate, resulting in a spot-like portion (luminance defect) in which the luminance decreases in a spot on the light wavelength conversion sheet. There is. The dot-like luminance defect is more easily visually recognized than when the quantum dots are deteriorated as a whole and the luminance is uniformly lowered. Further, at present, it is desired to further reduce the thickness of the light wavelength conversion sheet and reduce the manufacturing cost.

  The present invention has been made to solve the above problems. That is, it is possible to suppress the dot-like luminance defect while suppressing the deterioration of the quantum dots, and it is possible to reduce the thickness and manufacturing cost, a light wavelength conversion sheet, a backlight device including the same, an image display device, And it aims at providing the manufacturing method of such a light wavelength conversion sheet.

According to one aspect of the present invention, there is provided a light wavelength conversion sheet, which comprises a binder resin and quantum dots dispersed in the binder resin, and a light wavelength conversion layer having a function of suppressing deterioration of the quantum dots. The light wavelength conversion sheet has a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90% and / or at 23 ° C. and a relative humidity of 90% in the light wavelength conversion sheet. There is provided a light wavelength conversion sheet having an oxygen transmittance of 0.1 cm ³ / (m ² · 24h · atm) or more.

  According to another aspect of the present invention, there is provided a backlight device including a light source and the light wavelength conversion sheet for receiving light from the light source.

  According to another aspect of the present invention, there is provided an image display device including the backlight device described above and a display panel arranged on a light emitting side of the backlight device.

According to another aspect of the present invention, a light wavelength conversion layer including a binder resin and quantum dots dispersed in the binder resin and having a function of suppressing deterioration of the quantum dots is provided, and the temperature is 40 ° C. and the relative humidity is 90. % Water vapor transmission rate of 0.1 g / (m ² · 24h) or more and / or 23 ° C, 90% relative humidity oxygen transmission rate of 0.1 cm ³ / (m ² · 24h · atm) or more A method of manufacturing a wavelength conversion sheet, a curable binder resin precursor, a quantum dot, and an optical wavelength conversion particle consisting of a light-transmissive barrier particle that surrounds the quantum dot and suppresses the transmission of water and oxygen. The composition for light wavelength conversion layer containing is coated on one surface of the substrate to form a coating film of the composition for light wavelength conversion layer, and the coating film is cured to form a light wavelength conversion layer. Optical wavelength conversion sheet There is provided a method of manufacturing a grate.

According to another aspect of the present invention, a light wavelength conversion layer including a binder resin and quantum dots dispersed in the binder resin and having a function of suppressing deterioration of the quantum dots is provided, and the temperature is 40 ° C. and the relative humidity is 90. % Water vapor transmission rate of 0.1 g / (m ² · 24h) or more and / or 23 ° C, 90% relative humidity oxygen transmission rate of 0.1 cm ³ / (m ² · 24h · atm) or more A method for manufacturing a wavelength conversion sheet, comprising a curable binder resin precursor containing one or more compounds selected from the group consisting of sulfur compounds, phosphorus compounds, and nitrogen compounds and a polymerizable compound, and quantum dots. The composition for light wavelength conversion layer containing is applied to one surface of the substrate to form a coating film of the composition for light wavelength conversion layer, and the coating film is cured to form a light wavelength conversion layer. Of optical wavelength conversion sheet A manufacturing method is provided.

  According to one aspect and another aspect of the present invention, it is possible to provide a light wavelength conversion sheet capable of suppressing the dot-like luminance defect while suppressing the deterioration of the quantum dots, and reducing the thickness and manufacturing cost. Further, according to another aspect of the present invention, it is possible to provide a backlight device and an image display device including such a light wavelength conversion sheet.

It is a schematic block diagram of the light wavelength conversion sheet which concerns on 1st Embodiment. It is a figure which shows the effect | action of the light wavelength conversion sheet which concerns on 1st Embodiment. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on 1st Embodiment. FIG. 6 is a perspective view of another light wavelength conversion sheet according to the first embodiment. FIG. 5 is a cross-sectional view of the light wavelength conversion sheet of FIG. 4, taken along line I-I. FIG. 6 is a perspective view of another light wavelength conversion sheet according to the first embodiment. It is sectional drawing which followed the II-II line of the light wavelength conversion sheet of FIG. It is a schematic block diagram of the other light wavelength conversion sheet which concerns on 1st Embodiment. It is a typical manufacturing process drawing of the light wavelength conversion sheet according to the first embodiment. FIG. 1 is a schematic configuration diagram of an image display device including a backlight device according to a first embodiment. FIG. 11 is a perspective view of the lens sheet shown in FIG. 10. It is a schematic block diagram of the other backlight apparatus which concerns on 1st Embodiment. It is a schematic block diagram of the light wavelength conversion sheet which concerns on 2nd Embodiment. It is a typical manufacturing process figure of the light wavelength conversion sheet concerning a 2nd embodiment. It is a typical manufacturing process figure of the light wavelength conversion sheet concerning a 2nd embodiment.

[First Embodiment]
Hereinafter, the light wavelength conversion sheet, the backlight device, and the image display device according to the first embodiment of the present invention will be described with reference to the drawings. In the present specification, terms such as “sheet” and “film” are not distinguished from each other based only on the difference in designation. Therefore, for example, "film" is used to include a member that is also called a sheet, and "sheet" is used to include a member that can also be called a film. FIG. 1 is a schematic configuration diagram of a light wavelength conversion sheet according to the present embodiment, FIG. 2 is a view showing an operation of the light wavelength conversion sheet according to the present embodiment, and FIGS. 3 and 8 are related to the present embodiment. It is a schematic block diagram of another light wavelength conversion sheet. FIG. 4 is a perspective view of another light wavelength conversion sheet according to this embodiment, FIG. 5 is a cross-sectional view of the light wavelength conversion sheet of FIG. 4 taken along the line I-I, and FIG. 6 shows this embodiment. It is a perspective view of the other light wavelength conversion sheet which concerns, FIG. 7 is sectional drawing which followed the II-II line of the light wavelength conversion sheet of FIG. 6, and FIG. 9 is a model of the light wavelength conversion sheet which concerns on this embodiment. It is a typical manufacturing process drawing.

<<< Light wavelength conversion sheet >>
The light wavelength conversion sheet 10 shown in FIG. 1 is a sheet that converts the wavelength of a part of the incident light into another wavelength and emits another part of the incident light and the wavelength-converted light. is there. The light wavelength conversion sheet 10 has a single layer structure. That is, the light wavelength conversion sheet 10 includes only the light wavelength conversion layer 11, and the light wavelength conversion sheet 10 does not include a barrier film.

The light wavelength conversion sheet 10 has a water vapor transmission rate (WVTR: Water Vaper Transmission Rate) of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or 23 ° C. relative to the entire sheet. Oxygen transmission rate (OTR) at a humidity of 90% is 0.1 cm ³ / (m ² · 24h · atm) or more.

The water vapor transmission rate is a numerical value obtained by a method based on JIS K7129. The water vapor transmission rate can be measured using a water vapor transmission rate measuring device (product name “DELTAPERM” (manufactured by Technolox), product name “PERMATRAN-W3 / 31” (manufactured by MOCON). The oxygen permeability is a numerical value obtained by a method based on JIS K7126. The oxygen permeability can be measured using an oxygen gas permeability measuring device (product names “OX-TRAN 2/20” and “OX-TRAN 2/21”, both manufactured by MOCON). Since the conventional light wavelength conversion sheet has the barrier film formed, the light wavelength conversion sheet 10 has a higher water vapor transmission rate and / or oxygen transmission rate than the conventional light wavelength conversion sheet, that is, The wavelength conversion sheet 10 is more permeable to moisture and / or oxygen than the conventional light wavelength conversion sheet. As will be described later, when the light wavelength conversion sheet is provided with a light transmissive base material and an optical member in addition to the light wavelength conversion layer, the water vapor transmission rate is the light including the light transmissive base material and the optical member. It is the water vapor transmission rate of the entire wavelength conversion sheet, and the oxygen transmission rate is the oxygen transmission rate of the entire light wavelength conversion sheet including the light transmissive substrate and the optical member. Here, the “barrier film” in the present specification means that the film itself has a water vapor transmission rate of less than 0.1 g / (m ² · 24 h) at 40 ° C. and a relative humidity of 90%, and at 23 ° C. and a relative humidity. It means a film having an oxygen transmission rate at 90% of less than 0.1 cm ³ / (m ² · 24h · atm). The barrier film includes not only a film having a single layer structure but also a film having a multilayer structure.

The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 10 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 10. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more.

  Before and after the durability test in which the light wavelength conversion sheet 10 is left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours, wavelength conversion is performed by the quantum dots 15 on the entire one surface 10A of the light wavelength conversion sheet 10. When the brightness of the light emitted from the central portion of the other surface 10B, which is the surface opposite to the surface 10A of the light wavelength conversion sheet 10, is measured by irradiating the same wavelength of light, the light wavelength before the durability test The change rate of the luminance of the light emitted from the central portion of the surface 10B of the light wavelength conversion sheet 10 after the durability test with respect to the luminance of the light emitted from the central portion of the surface 10B of the conversion sheet 10 is within ± 10%. It is preferable. The rate of change in the luminance of the light emitted from the central portion of the surface 10B of the light wavelength conversion sheet 10 after the durability test is ± with respect to the luminance of the light emitted from the central portion of the surface 10B of the light wavelength conversion sheet 10 before the durability test. It is preferably within 5%.

  The light with which the entire surface of one surface of the light wavelength conversion sheet is irradiated may include light that is wavelength-converted by the quantum dots and may include light that is not wavelength-converted by the quantum dots. When the light wavelength conversion layer includes, for example, both a quantum dot that converts blue light into green light and a quantum dot that converts blue light into red light, the light whose wavelength is converted by the quantum dots is blue light. Can be used. In the above, the light wavelength conversion sheet is irradiated with a predetermined amount of light before and after the durability test, and when the light wavelength conversion sheet is irradiated with a different amount of light before and after the durability test, an accurate luminance change rate is obtained. Since it cannot be measured, in order to accurately measure the rate of change in luminance, the light wavelength conversion sheet was irradiated with a certain amount of light before and after the durability test.

Regarding the rate of change in brightness before and after the durability test, the rate of change in brightness was A, the brightness of the light emitted from the central portion of the surface 10B of the light wavelength conversion sheet 10 before the humidity and heat resistance test was B, and the light after the humidity and heat resistance test was performed. When the brightness of the light emitted from the central portion of the surface 10B of the wavelength conversion sheet 10 is C, it can be calculated by the following formula.
A = (C−B) / B × 100

  The brightness before and after the heat and humidity resistance test was measured by measuring the light emitted from the center of the other surface of the light wavelength conversion sheet from the thickness direction of the light wavelength conversion sheet with a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta Co., Ltd. ) Is used under the condition of a measurement angle of 1 °.

  The brightness of the light emitted from the center of the other surface of the light wavelength conversion sheet can be obtained by directly or indirectly measuring the brightness of the light emitted from the center of the other surface of the light wavelength conversion sheet. It is possible. That is, although it may be obtained by directly measuring the brightness of the light emitted from the central portion of the other surface of the light wavelength conversion sheet, the light wavelength conversion sheet is incorporated into a backlight device including a light source and a lens sheet, It may be obtained by measuring the brightness of the light emitted from the central portion of the light emitting surface of the backlight device through the central portion of the other surface of the light wavelength conversion sheet. However, it goes without saying that the measurement of the brightness before the durability test and the measurement of the brightness after the durability test are performed under the same conditions.

  When the light wavelength conversion sheet 10 was subjected to a durability test of leaving it in an environment of 60 ° C. and 90% relative humidity for 500 hours, the deterioration width of the peripheral portion of the light wavelength conversion sheet 10 after the durability test was 5 mm or less. Is preferably 3 mm or less, and more preferably 3 mm or less. Here, the deterioration width of the peripheral portion of the light wavelength conversion sheet is obtained as follows. First, the light wavelength conversion sheet after the durability test was incorporated into a backlight device, and the luminance distribution on the light emitting surface of the backlight device when the backlight device was turned on was measured from the thickness direction of the light wavelength conversion sheet in a 2D color luminance meter (product name "UA -200 ", manufactured by Topcon Technohouse). Then, from the measured luminance distribution of the light emitting surface, a position where the luminance is 80% with respect to the luminance of the central portion of the light emitting surface (hereinafter, this position is referred to as "80% luminance position") is obtained, and the light emitting surface is measured. The shortest distance from the edge closest to the 80% luminance position to the 80% luminance position is calculated. Then, this shortest distance is randomly obtained for 20 locations, and the average value of the shortest distances of the 20 locations is set as the deterioration width of the peripheral portion of the light wavelength conversion sheet.

  The thickness of the light wavelength conversion sheet 10 is preferably 10 μm or more and 150 μm or less. When the film thickness of the light wavelength conversion sheet 10 is in this range, it is suitable for reducing the weight and thinning the backlight device.

  The film thickness of the light wavelength conversion sheet 10 is obtained by photographing a cross section of the light wavelength conversion sheet using a scanning electron microscope (SEM), a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The film thickness of the light wavelength conversion sheet is measured at 20 points in the image, and the average value of the film thickness at the 20 points is taken. Among these, it is preferable to use SEM, considering that the film thickness of the light wavelength conversion sheet 10 is on the order of μm. In the case of SEM, the acceleration voltage is preferably 30 kV and the magnification is 1000 to 7000 times, and in the case of TEM or STEM, the acceleration voltage is preferably 30 kV and the magnification is preferably 50,000 to 300,000 times.

  At least one surface of the light wavelength conversion sheet 10 is an uneven surface having an arithmetic average roughness (Ra) of 0.1 μm or more in order to prevent the light wavelength conversion sheet 10 and other members from sticking to each other. It is preferable. The uneven surface can be formed by a shaping process, but can also be formed by including an anti-blocking agent in the light wavelength conversion sheet 10.

  The light wavelength conversion layer 11 includes, for example, a binder resin 12 and light wavelength conversion particles 13 dispersed in the binder resin 12. In the present embodiment, the light wavelength conversion layer includes the binder resin 12 and the light wavelength conversion particles 13, but it is sufficient that the light wavelength conversion layer includes the binder resin and the quantum dots, and does not need to include the light wavelength conversion particles. Good. Further, the light wavelength conversion sheet or the light wavelength conversion layer may further include light scattering particles 14 and an anti-blocking agent (not shown). As used herein, the term “light scattering” means light scattering caused by particles inside the light wavelength conversion sheet.

  The light wavelength conversion layer 11 has a function of suppressing deterioration of the quantum dots 15 described later. The means for imparting the deterioration suppressing function of the quantum dots 15 to the light wavelength conversion layer 11 is not particularly limited, but enclosing the quantum dots with barrier particles as in the present embodiment, or fluorescent as in the second embodiment. The content of at least one element selected from the group consisting of sulfur, phosphorus, and nitrogen in the light wavelength conversion layer measured by X-ray analysis may be 0.5% by mass or more.

The water vapor permeability of the entire sheet at 40 ° C. and 90% relative humidity is 0.1 g / (m ² · 24 h) or more and / or the oxygen permeability at 23 ° C. and 90% relative humidity is 0.1 cm ³ / ( In the light wavelength conversion sheet having m ² · 24h · atm) or more, whether or not the light wavelength conversion layer 11 has the deterioration suppressing function of the quantum dots 15 is determined as follows. . First, the light wavelength conversion sheet is left in an environment of 60 ° C. and a relative humidity of 90% for 100 hours, and a predetermined amount of light wavelength-converted by quantum dots is applied to the entire one surface of the light wavelength conversion sheet before the deterioration resistance test. By irradiating light, the brightness of the light emitted from the central portion of the other surface, which is the surface opposite to the surface of the light wavelength conversion sheet, is measured. The brightness is measured by measuring the light emitted from the center of the other surface of the light wavelength conversion sheet from the thickness direction of the light wavelength conversion sheet using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta Co., Ltd.). It is measured under the condition of an angle of 1 °. Next, the light wavelength conversion sheet is subjected to the deterioration resistance test, and then, under the same conditions as above, the luminance of the light emitted from the central portion of the other surface of the light wavelength conversion sheet after the deterioration resistance test is measured. . Then, the rate of change in the luminance of the light emitted from the central portion of the light wavelength conversion sheet after the deterioration resistance test with respect to the luminance of the light emitted from the central portion of the light wavelength conversion sheet before the deterioration resistance test is obtained. If the rate of change in luminance is within ± 10%, it is determined that the light wavelength conversion layer has a quantum dot deterioration suppressing function.

Regarding the luminance change rate before and after the deterioration resistance test, the luminance change rate is D, the brightness of the light emitted from the central portion of the light wavelength conversion sheet before the deterioration resistance test is E, and the light wavelength after the deterioration resistance test is When the brightness of the light emitted from the central portion of the conversion sheet is F, it is calculated by the following formula.
D = (FE) / E × 100

In the above, whether or not the light wavelength conversion layer has a deterioration suppressing function of the quantum dots is determined from the luminance change rate before and after the deterioration resistance test of the entire light wavelength conversion sheet. That is, even if a light wavelength conversion sheet in which at least one surface of the light wavelength conversion layer is provided with any base material or film, the light wavelength conversion sheet can be exposed to light without peeling off the base material or film from the light wavelength conversion layer. From the luminance change rate of the entire light wavelength conversion sheet in which this substrate or film is provided on the surface of the wavelength conversion layer, it is determined whether or not the light wavelength conversion layer has a deterioration suppressing function of quantum dots. . This is for the following reason. First, the entire sheet has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and 90% relative humidity and / or an oxygen transmission rate of 0.1 cm ³ at 23 ° C. and 90% relative humidity. In the light wavelength conversion sheet having a thickness of / (m ² · 24h · atm) or more, the water vapor transmission rate and / or the oxygen transmission rate is high. Therefore, unless some measures are taken, the quantum dots are deteriorated by water and oxygen. Will end up. Here, even if some substrate or film is provided on at least one surface of the light wavelength conversion layer, in the light wavelength conversion sheet having high water vapor transmission rate or oxygen transmission rate as described above, Since the base material, the film, and the like also have high water vapor transmission rate and oxygen transmission rate, the deterioration of the quantum dots cannot be suppressed by the base material, the film, and the like. Therefore, in the light wavelength conversion sheet having such high water vapor transmission rate and oxygen transmission rate, when the rate of change in luminance before and after the deterioration resistance test is within ± 10%, the quantum dots of It can be considered that the rate of change in luminance was within ± 10% because the deterioration of the quantum dots was suppressed by the light wavelength conversion layer rather than the deterioration was suppressed. Therefore, not only the light wavelength conversion sheet composed of the light wavelength conversion layer alone, before and after the deterioration resistance test in the light wavelength conversion sheet provided with the substrate or film on at least one surface of the light wavelength conversion layer The luminance change rate can be grasped as an index for judging the presence or absence of the deterioration suppressing function of the quantum dots. Therefore, even if the light wavelength conversion sheet is provided with a substrate or a film on at least one surface of the light wavelength conversion layer, from the rate of change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet, the light wavelength It was decided whether or not the conversion layer had a function of suppressing deterioration of the quantum dots.

  The brightness of the light emitted from the central part of the other surface of the light wavelength conversion sheet in the deterioration resistance test directly or indirectly measures the brightness of the light emitted from the central part of the other surface of the light wavelength conversion sheet. It is possible to obtain it. That is, although it may be obtained by directly measuring the brightness of the light emitted from the central portion of the other surface of the light wavelength conversion sheet, the light wavelength conversion sheet is incorporated into a backlight device including a light source and a lens sheet, It may be obtained by measuring the brightness of the light emitted from the central portion of the light emitting surface of the backlight device through the central portion of the other surface of the light wavelength conversion sheet.

<< binder resin >>
The binder resin 12 is not particularly limited, but includes a cured product (polymerized product, cross-linked product) of a curable binder resin precursor. The “curable binder resin precursor” in the present specification means a compound which becomes a component of the binder resin when cured. Examples of the curable binder resin precursor include a polymerizable compound (curable compound). The polymerizable compound is a polymerizable compound, and examples thereof include an ionizing radiation-polymerizable compound (ionizing radiation-curable compound) and / or a heat-polymerizable compound (thermosetting compound).

<Ionizing radiation-polymerizable compound>
The ionizing radiation-polymerizable compound has at least one ionizing radiation-polymerizable functional group in the molecule. In the present specification, the "ionizing radiation-polymerizable functional group" is a functional group capable of undergoing a polymerization reaction upon irradiation with ionizing radiation. Examples of the ionizing radiation-polymerizable functional group include ethylenic double bonds such as (meth) acryloyl group, vinyl group and allyl group. The “(meth) acryloyl group” is meant to include both “acryloyl group” and “methacryloyl group”. In addition, examples of the ionizing radiation irradiated when polymerizing the photopolymerizable compound include visible light, ultraviolet rays, X rays, electron rays, α rays, β rays, and γ rays.

  Examples of the ionizing radiation-polymerizable compound include an ionizing radiation-polymerizable monomer, an ionizing radiation-polymerizable oligomer, and an ionizing radiation-polymerizable prepolymer, which can be appropriately adjusted and used. The ionizing radiation-polymerizable compound is preferably a combination of an ionizing radiation-polymerizable monomer and an ionizing radiation-polymerizable oligomer or an ionizing radiation-polymerizable prepolymer.

  The photopolymerizable monomer has a weight average molecular weight of 1,000 or less. Examples of the photopolymerizable monomer include monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, ethylene glycol di (meth) acrylate, and the like. Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol Tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol (meth) (meth) acrylic acid esters such as acrylate.

  The photopolymerizable oligomer has a weight average molecular weight of more than 1,000 and 10,000 or less. As the photopolymerizable oligomer, a polyfunctional oligomer having two or more functional groups is preferable, and a polyfunctional oligomer having three (trifunctional) or more photopolymerizable functional groups is preferable. Examples of the polyfunctional oligomer include polyester (meth) acrylate, urethane (meth) acrylate, polyester-urethane (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, isocyanurate. Examples thereof include (meth) acrylate and epoxy (meth) acrylate.

  The photopolymerizable prepolymer has a weight average molecular weight of more than 10,000, and the weight average molecular weight is preferably 10,000 or more and 80,000 or less, more preferably 10,000 or more and 40,000 or less. If the weight average molecular weight is more than 80,000, the viscosity is high and the coating suitability is deteriorated, and the appearance of the obtained light wavelength conversion layer may be deteriorated. Examples of the polyfunctional prepolymer include urethane (meth) acrylate, isocyanurate (meth) acrylate, polyester-urethane (meth) acrylate, and epoxy (meth) acrylate.

<Thermopolymerizable compound>
The thermopolymerizable compound has at least one thermopolymerizable functional group in the molecule. Examples of the thermopolymerizable functional group include cyclic ether groups such as epoxy groups and oxetanyl groups, vinyl ether groups, isocyanate groups, glycidyl groups, hydroxyl groups, carboxyl groups, amino groups, amide groups, and the like.

  The heat-polymerizable compound is not particularly limited, and examples thereof include phenol compounds, urea compounds, diallyl phthalate compounds, melamine compounds, guanamine compounds, unsaturated polyester compounds, urethane compounds, epoxy compounds, aminoalkyd compounds, melamine-urea cocondensation. Examples thereof include compounds, silicon compounds, polysiloxane compounds and the like. The thermosetting resins may be used alone or in combination of two or more. Among these, epoxy compounds and urethane compounds are preferable from the viewpoint of curability and heat resistance. The heat-polymerizable compound may be a heat-polymerizable monomer, a heat-polymerizable oligomer, a heat-polymerizable resin (prepolymer), or a mixture thereof.

  The epoxy compound is not particularly limited as long as it has an epoxy group in one molecule, and examples thereof include a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a brominated bisphenol A type epoxy compound, a bisphenol S type epoxy compound, Diphenyl ether type epoxy compound, hydroquinone type epoxy compound, naphthalene type epoxy compound, biphenyl type epoxy compound, fluorene type epoxy compound, phenol novolac type epoxy compound, orthocresol novolac type epoxy compound, trishydroxyphenylmethane type epoxy compound, trifunctional epoxy Compounds, tetraphenylolethane type epoxy compounds, dicyclopentadienephenol type epoxy compounds, hydrogenated bisphenol A type epoxy compounds, bi Phenol A 含核 polyol type epoxy compounds, polypropylene glycol type epoxy compounds, glycidyl ester type epoxy compounds, glycidyl amine type epoxy compounds, glyoxal type epoxy compounds, alicyclic epoxy compounds, heterocyclic epoxy compounds and the like can be used. The epoxy compound may be a monomer or a resin.

  When the barrier particles 16 described below are inorganic oxide particles, hydroxyl groups are present on the surface of the barrier particles 16, or mercapto groups, (meth) acryloyl groups, vinyl groups, and styryl groups are formed by surface modification with a silane coupling agent. Since one or more groups selected from the group consisting of a group, an epoxy group, an isocyanate group, and an amino group may be present, the curable binder resin precursor may be a functional group that reacts with a hydroxyl group or a mercapto group. It is preferable to have. Examples of such a functional group include an epoxy group, an isocyanate group, a mercapto group, a (meth) acryloyl group, a vinyl group, and an allyl group.

<< Optical wavelength conversion particles >>
The light wavelength conversion particle 13 includes a quantum dot 15 that performs wavelength conversion of light, and a light transmissive barrier particle 16 that surrounds the quantum dot 15 and suppresses the transmission of moisture and oxygen. There is no air layer between the quantum dots 15 and the barrier particles 16, and the surfaces of the quantum dots 15 are in close contact with the barrier particles 16.

  As shown in FIG. 2, when light is incident from the light incident surface 10A of the light wavelength conversion sheet 10, the light L1 incident on the quantum dots 15 is converted into light L2 having a different wavelength from the light L1. The light exits from the light exit surface 10B, which is the surface opposite to the light entrance surface 10A. On the other hand, even when light is incident from the light incident surface 10A, the light L1 passing between the quantum dots 15 is emitted from the light emitting surface 10B without wavelength conversion.

  The light wavelength conversion particles 13 preferably include 1 or more and 50 or less quantum dots 15 each, and 1 or more and 40 or less or 1 or 35 quantum dots 15 or less per one. Is more preferable. When the number of quantum dots contained in one light wavelength conversion particle is less than 1, the brightness may be lowered, and when the number of quantum dots contained in one light wavelength conversion particle exceeds 50, the quantum Density quenching that causes quenching due to energy transfer between dots may reduce the luminous efficiency. The number of quantum dots contained in one light wavelength conversion particle is 100,000 times the cross section of 20 light wavelength conversion particles randomly using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). Obtained by taking a photograph at a magnification of up to 500,000 times, calculating the number of quantum dots contained in one light wavelength conversion particle from the obtained cross-sectional image, and calculating the average value of the calculated number of quantum dots. be able to.

  Each light wavelength conversion particle 13 includes two or more quantum dots 15, and the average distance between the quantum dots 15 in the quantum dots 15 included in one light wavelength conversion particle 13 is 1 nm or more. It is preferable. If the average distance between the quantum dots is less than 1 nm, energy transfer between the quantum dots is likely to occur, and the luminous efficiency may decrease. The average distance between the quantum dots was obtained by randomly taking a cross section of 20 light wavelength conversion particles with a transmission electron microscope or a scanning transmission electron microscope at a magnification of 100,000 to 500,000 times. It can be obtained by calculating the distance between the quantum dots from the image and calculating the average value of the calculated distances between the quantum dots. The upper limit of the average distance between the quantum dots 15 in the quantum dots 15 is more preferably 100 nm or less.

  The average particle diameter of the light wavelength conversion particles 13 is preferably 10 nm or more and 500 nm or less. If the average particle size of the light wavelength conversion particles is less than 10 nm, it may not be possible to sufficiently impart barrier properties to the quantum dots, and the quantum dots may cause oxidative deterioration, and if it exceeds 500 nm, Although the reason is not clear, the barrier properties of the barrier particles may become unstable. The average particle diameter of the light wavelength conversion particles is obtained by measuring the particle diameter of 20 light wavelength conversion particles in cross-sectional observation of the light wavelength conversion sheet with a transmission electron microscope or a scanning transmission electron microscope, and calculating the average value. You can ask. The lower limit of the average particle diameter of the light wavelength conversion particles 13 is preferably 20 nm or more, and the upper limit of the average particle diameter of the light wavelength conversion particles 13 is preferably 200 nm or less, more preferably 100 nm or less.

<Quantum dot>
The quantum dots 15 are nano-sized semiconductor particles having a quantum confinement effect. The particle size and average particle size of the quantum dots 15 are, for example, 1 nm or more and 20 nm or less. When the quantum dot 15 absorbs light from the excitation source and reaches the energy excited state, the quantum dot 15 emits energy corresponding to the energy band gap of the quantum dot 15. Therefore, if the particle diameter of the quantum dots 15 or the composition of the substance is adjusted, the energy band gap can be adjusted, and energy in wavelength bands of various levels can be obtained. In particular, the quantum dots 15 can generate strong fluorescence in a narrow wavelength band.

  Specifically, the energy band gap of the quantum dots 15 increases as the particle diameter decreases. That is, as the crystal size becomes smaller, the quantum dot emission shifts to the blue side, that is, to the high energy side. Therefore, by changing the particle size of the quantum dots, the emission wavelength can be adjusted over the entire wavelength range of the spectrum in the ultraviolet region, the visible region, and the infrared region. For example, when the quantum dots are composed of CdSe / ZnS described later, blue light is emitted when the particle size of the quantum dots is 2.0 nm or more and 4.0 nm or less, and the particle size of the quantum dots is 3.0 nm. When it is 6.0 nm or less, green light is emitted, and when the particle size of the quantum dot is 4.5 nm or more and 10.0 nm or less, red light is emitted. In the above, the particle size range of the quantum dots emitting blue light and the particle size range of the quantum dots emitting green light partially overlap, and the particle size of the quantum dots emitting green light and the red light are Although the range of particle diameters of emitted quantum dots partially overlaps, even for quantum dots having the same particle diameter, the emission color may differ depending on the thickness of the quantum dot shell, so there is no contradiction. Not a thing.

  In the present specification, "blue light" is light having a wavelength range of 380 nm or more and less than 480 nm, "green light" is light having a wavelength range of 480 nm or more and less than 590 nm, and "red light" is It is light having a wavelength range of 590 nm or more and 750 nm or less.

  As the quantum dot 15, one kind of quantum dot may be used, but it is also possible to use two or more kinds of quantum dots each having an emission band of a single wavelength region due to the difference in particle diameter, material, or the like. is there. As shown in FIG. 1, the light wavelength conversion sheet 10 includes, as the quantum dots 15, a first quantum dot 15A and a second quantum dot 15B having an emission band in a wavelength range different from that of the first quantum dot 15A. Includes and.

  When two or more kinds of quantum dots each having an emission band of a single wavelength region are used as the quantum dots, two or more kinds of quantum dots may be included per one light wavelength conversion particle, and the light wavelength conversion particle 1 Each piece may include one type of quantum dot. When a quantum dot that converts blue light into green light and a quantum dot that converts blue light into red light are included in one light wavelength conversion particle, the blue light is converted into green light. In some cases, the green light generated by the quantum dots that are absorbed is absorbed by the quantum dots that convert the blue light into the red light, and in this case, one type of quantum dot is included in one light wavelength conversion particle. It is preferable to include only.

  As described above, since the light emitted from the light wavelength conversion sheet 10 includes some light whose wavelength is not converted, a light source that emits blue light is used as the light source, and the blue light is converted into green light as the first quantum dots 15A. When a quantum dot is used and a quantum dot that converts blue light into red light is used as the second quantum dot 15B, light in which blue light, green light, and red light are mixed is emitted from the light wavelength conversion sheet 10. Can be made.

  The quantum dots 15 can generate strong fluorescence in a desired narrow wavelength range. Therefore, the backlight device using the light wavelength conversion sheet 10 can illuminate the display panel with light of the three primary colors having excellent color purity. In this case, the display panel has excellent color reproducibility.

  The quantum dots 15 may have a core-shell structure having a core mainly made of a semiconductor compound of about 2 nm or more and 10 nm or less and a shell made of a semiconductor compound different from this core. The shell has a function as a protective layer that protects the core.

  Examples of the material serving as the core include MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, and HgTe. II-VI semiconductor compounds such as AlN, AlP, AlAs, AlSb, GaAs, GaP, GaN, GaSb, InN, InAs, InP, InSb, TiN, TiP, TiAs and TiSb, and III-V semiconductor compounds. , Group IV semiconductors such as Si, Ge and Pb, and semiconductor crystals containing a semiconductor compound or semiconductor. Alternatively, a semiconductor crystal containing a semiconductor compound containing three or more elements such as InGaP can be used. Among these, semiconductor crystals such as CdS, CdSe, CdTe, InP, and InGaP are preferable from the viewpoints of ease of production, controllability of particle diameter capable of obtaining light emission in the visible region, and the like.

  The shell uses a semiconductor compound having a bandgap higher than that of the semiconductor compound forming the core so that the excitons are confined in the core, whereby the luminous efficiency of the quantum dots can be increased. Examples of the core-shell structure (core / shell) having such a band gap magnitude relation include CdSe / ZnS, CdSe / ZnSe, CdSe / CdS, CdTe / CdS, InP / ZnS, Gap / ZnS, Si / ZnS, Examples include InN / GaN, InP / CdSSe, InP / ZnSeTe, InGaP / ZnSe, InGaP / ZnS, Si / AlP, InP / ZnSTe, InGaP / ZnSTe, InGaP / ZnSSe, and the like.

  The shape of the quantum dots 15 is not particularly limited, and may be, for example, a spherical shape, a rod shape, a disk shape, or another shape. If the quantum dots 15 are not spherical, the particle size of the quantum dots 16 can be a true spherical value having the same volume.

  Information such as the particle size, average particle size, shape, and dispersion state of the quantum dots 15 can be obtained with a transmission electron microscope or a scanning transmission electron microscope. The average particle diameter of the quantum dots can be obtained as an average value of the diameters of 20 quantum dots measured by observing the cross section of the light wavelength conversion layer with a transmission electron microscope or a scanning transmission electron microscope. Moreover, since the emission color of the quantum dot changes depending on the particle diameter, it is possible to determine the particle diameter of the quantum dot by confirming the emission color of the quantum dot. The crystal structure and crystallite size of the quantum dots can be known by X-ray crystal diffraction (XRD). Furthermore, it is also possible to obtain information regarding the particle size of the quantum dots and the like from the ultraviolet-visible (UV-Vis) absorption spectrum.

<Barrier particles>
The barrier particles 16 surround the quantum dots 15, have optical transparency, and have barrier properties that suppress the permeation of moisture and oxygen. By enclosing the quantum dots 15 with the barrier particles 16, it is possible to prevent the quantum dots 15 from coming into contact with water or oxygen, and thus it is possible to prevent the quantum dots 15 from being deteriorated by water or oxygen. As a result, it is possible to suppress a decrease in luminous efficiency of the quantum dots 15 without providing a barrier layer. In the present specification, “light transmissive” means having a property of transmitting light, and “light transmissive” also includes transparency. In the present invention, since the quantum dots are wrapped with barrier particles, it can be said that the barrier particles have a light-transmitting property if light emission from the quantum dots emitted from the light wavelength conversion sheet can be confirmed. The light emission of the quantum dots can be confirmed using a fluorometer. The “barrier property” was evaluated by performing a durability test in which the light wavelength conversion sheet was left in an environment of 40 ° C. and a relative humidity of 90% for 300 hours, and the reduction rate of the emission peak intensity of the light wavelength conversion sheet before and after the durability test was 10 If it is within%, it can be judged that the barrier particles have barrier properties. However, since the light from the light source that has passed through the light wavelength conversion sheet is not the light generated by the light emission of the light wavelength conversion sheet, the peak intensity of the light from the light source that has passed through the light wavelength conversion sheet is the light emission of the light wavelength conversion sheet. It is not included in the peak intensity. Further, when there are a plurality of emission peaks of the light emitted from the light wavelength conversion sheet, “the reduction rate of the emission peak intensity is within 10%” means that the reduction rate of the intensity at each emission peak is within 10%. Means that. The decrease rate of the emission peak of the light wavelength conversion sheet before and after the durability test is G, the emission peak intensity of the light wavelength conversion sheet before the durability test is H, and the emission peak intensity of the light wavelength conversion sheet after the durability test is I. Then, the reduction rate (G) of the emission peak of the light wavelength conversion sheet before and after the durability test is obtained by the following formula.
G = (HI) / H × 100

The material for forming the barrier particles 16 is not particularly limited as long as it has a light-transmitting property and a barrier property, and examples thereof include an inorganic oxide. Specifically, examples of the inorganic oxide include silicon oxide (SiO _x ) such as silica, aluminum oxide (Al _n O _m ), such as alumina, titanium oxide (TiO ₂ ), yttrium oxide, and boron oxide (B ₂ O ₃ ), calcium oxide (CaO), silicon oxynitride carbide (SiO _x N _y C _z ), and the like. Among them, silica or alumina such as glass is preferable from the viewpoint of low permeability to oxygen and water vapor. preferable. These materials may be used alone or in combination of two or more kinds. It is also possible to use an inorganic oxide other than the oxide semiconductor.

  When the quantum dot 15 contains Cd, the thickness of the barrier particle 16 (distance from the surface of the quantum dot to the outer surface of the barrier particle) is 2 nm or more in order to prevent elution of Cd contained in the quantum dot 15. Is preferable and 4 nm or more is more preferable. When the average particle diameter of the light wavelength conversion particles 13 is about 50 nm, the thickness of the barrier particles 16 can be 10 nm or more. Further, when the average particle diameter of the light wavelength conversion particles 13 is about 100 nm, the thickness of the barrier particles 16 can be 20 nm or more. The thickness of the barrier particles can be easily measured as an outer portion that does not include quantum dots by observation with a transmission electron microscope. When the thickness varies depending on the position of the peripheral edge of the barrier particle, the thickness of the barrier particle is determined by averaging the entire peripheral edge of the barrier particle.

  From the viewpoint of improving the adhesiveness with the binder resin 12, the barrier particles 16 are preferably chemically bonded to the binder resin 12. This chemical bonding can be performed by the barrier particles 16 surface-modified with a silane coupling agent.

  The silane coupling agent, depending on the type of curable binder resin precursor used, vinyl group, epoxy group, styryl group, methacryl group, acryl group, amino group, ureido group, mercapto group, sulfide group and isocyanate group It is possible to use those having one or more reactive functional groups selected from the group consisting of: When a compound having a (meth) acryloyl group is used as the curable binder resin precursor, the coupling agent is at least one selected from the group consisting of a mercapto group, a (meth) acryloyl group, a vinyl group and a styryl group. It is preferable to have the reactive functional group of. When a compound having at least one group selected from the group consisting of an epoxy group, an isocyanate group, and a hydroxyl group is used as the curable binder resin precursor, the silane coupling agent is an epoxy group, an isocyanate group, or a mercapto. It is preferable to have at least one reactive functional group selected from the group consisting of a group and an amino group.

  Examples of the silane coupling agent having a mercapto group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltriethoxysilane.

  Examples of the silane coupling agent having a (meth) acrylic group include 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltrimethoxysilane. Examples thereof include ethoxysilane and 3-acryloyloxypropyltriethoxysilane.

  Examples of the silane coupling agent having a vinyl group include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane and the like. Examples of the styryl group-containing silane coupling agent include p-styryltrimethoxysilane.

  As the silane coupling agent having an epoxy group, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycid Examples include xypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane.

  Examples of the silane coupling agent having an isocyanate group include 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane.

  Examples of the silane coupling agent having an amino group include 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, and N-2- (aminoethyl) -3-aminopropyltrimethylene. Oxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl)- 2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride and the like can be mentioned.

  As a method for surface-treating the barrier particles 16 with a silane coupling agent, a dry method of spraying the silane coupling agent on the barrier particles 16 or a method in which the barrier particles 16 are dispersed in a solvent and then the silane coupling agent is added and reacted A wet method and the like can be mentioned.

<Light scattering particles>
The light-scattering particles 14 are particles having a function of changing the traveling direction of light by scattering the light that has entered the light wavelength conversion sheet 10.

  The average particle diameter of the light scattering particles 14 is preferably 20 times or more and 2000 times or less, and more preferably 50 to 1000 times, the average particle diameter of the quantum dots 15. If the average particle diameter of the light scattering particles is less than 20 times the average particle diameter of the quantum dots, sufficient light scattering performance may not be obtained in the light wavelength conversion layer, and the average particle diameter of the light scattering particles may be If it exceeds 2000 times the average particle diameter of the quantum dots, the number of light-scattering particles will decrease even if the addition amount is the same, so the number of scattering points will decrease and a sufficient light-scattering effect cannot be obtained. The average particle size of the light-scattering particles can be measured by the same method as the average particle size of the quantum dots described above.

  Specifically, the average particle diameter of the light scattering particles 14 is preferably, for example, 0.1 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 5 μm or less. When the average particle size of the light scattering particles is less than 0.1 μm, the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient, and in order to obtain sufficient light scattering properties, It is necessary to increase the addition amount. On the other hand, if the average particle size of the light-scattering particles exceeds 10 μm, the number of light-scattering particles decreases even if the addition amount (mass%) is the same, so the number of scattering points decreases and a sufficient light-scattering effect is obtained. I can't get it.

  The absolute value of the refractive index difference between the light scattering particles 14 and the binder resin 12 is preferably 0.05 or more, and more preferably 0.10 or more from the viewpoint of obtaining sufficient light scattering. Either of the refractive index of the light scattering particles 18 and the refractive index of the binder resin 12 may be larger. Here, as a method for measuring the refractive index of the light-scattering particles before being contained in the light wavelength conversion layer, for example, Becke method, minimum deviation method, deviation analysis, mode line method, ellipsometry method, etc. can do. Also, the refractive index of the binder resin is measured by an Abbe refractometer for a cured film of only the host matrix, which is obtained by coating, drying and curing a coating that does not contain quantum dots and light scattering particles from the coating liquid that forms the light wavelength conversion layer. It can be obtained by The binder resin (cured product) in the light wavelength conversion layer and the method for measuring the refractive index of the light-scattering particles include, for example, fragments of the light-scattering particles from the cured light-wavelength conversion layer, or a binder resin Becke's method can be used for taking out pieces in some form. In addition, the refractive index difference between the binder resin and the light-scattering particles is measured using a phase-shift laser interference microscope (such as a phase-shift laser interference microscope manufactured by FK Optics Laboratories or a two-beam interference microscope manufactured by Mizojiri Optical Co., Ltd.) can do. When the binder resin contains the above-mentioned (meth) acrylate and a resin other than that, the refractive index of the binder resin means the average refraction of the cured product by all the resin components contained except the light wavelength conversion particles. Means rate.

  The shape of the light-scattering particles 14 is not particularly limited, and includes, for example, spherical shape (true spherical shape, substantially true spherical shape, elliptic spherical shape, etc.), polyhedral shape, rod shape (cylindrical shape, prismatic shape, etc.), flat plate shape, scaly shape, indefinite shape Shape etc. are mentioned. The particle size of the light-scattering particles 14 can be a true spherical value having the same volume when the light-scattering particles are not spherical in shape.

  The light-scattering particles 14 are preferably chemically bonded to the binder resin 12 from the viewpoint of firmly fixing the light-scattering particles 14 in the binder resin 12. This chemical bond can be realized by using light-scattering particles whose surface is treated with a silane coupling agent. Examples of the silane coupling agent include those similar to the silane coupling agent described in the section of the barrier particles 16.

The light-scattering particles 14 are preferably inorganic particles and / or organic particles. Specifically, from the viewpoint of the difference in refractive index from the binder resin, antimony-doped tin oxide (ATO) particles, indium tin oxide ( (ITO) particles, MgO particles, Al ₂ O ₃ particles, TiO ₂ particles, BaTiO ₃ particles, Sb ₂ O ₅ particles, SiO ₂ particles, MgF ₂ particles, ZrO ₂ particles, ZnO particles, acrylic resin particles, styrene resin particles, It is preferably at least one kind of particles selected from the group consisting of melamine resin particles and urethane resin particles.

When the light-scattering particles 14 are inorganic particles, the light incident on the light wavelength conversion sheet 10 can be scattered appropriately, and the light wavelength conversion efficiency for the incident light can be improved appropriately. . In particular, the light scattering particles 14 are preferably at least one selected from the group consisting of Al ₂ O ₃ particles, TiO ₂ particles, BaTiO ₃ particles, Sb ₂ O ₅ particles, and ZrO ₂ particles. The light-scattering particles 14 may be made of two or more kinds of materials because the light-wavelength conversion sheet 10 can more appropriately improve the light-wavelength conversion efficiency with respect to incident light.

  The content of the light scattering particles 14 in the light wavelength conversion layer 11 is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 30% by mass or less. When the content of the light scattering particles is less than 1% by mass, the light scattering effect may not be sufficiently obtained, and when the content of the light scattering particles exceeds 50% by mass, Mie scattering occurs. Since it becomes difficult, the light-scattering effect may not be sufficiently obtained, and further, the workability may be deteriorated because there are too many light-scattering particles. The mass% of the light-scattering particles (in the case of inorganic) in the light wavelength conversion layer that is a cured product is roughly calculated by the same method as the method of calculating the mass% of the light wavelength conversion particles in the light wavelength conversion layer. can do. That is, similarly to the above, a part of the light wavelength conversion layer is sampled from the light wavelength conversion sheet, and then the binder resin contained in the sampled portion is dissolved or burned in a solvent to ash to remove the binder resin component. To do. After that, the components of the remaining light wavelength conversion particles and the light scattering particles are separated, and the masses of the separated components of the light scattering particles are measured. Then, the ratio of the mass of the light scattering particles contained in the sampled light wavelength conversion layer is calculated based on the mass of the sampled light wavelength conversion layer and the mass of the component of the light scattering particles.

<Anti-blocking agent>
The anti-blocking agent is a component that forms unevenness on the surface of the light wavelength conversion sheet 10 to prevent sticking between the light wavelength conversion sheet 10 and other members. As the anti-blocking agent, for example, particles having an average primary particle diameter of 100 to 1000 nm and fine particles of an inorganic compound such as silica and fine particles of an organic compound such as high-density polyethylene, polystyrene, polystyrene acryl can be used.

<< Method for producing light wavelength conversion particles >>
The light wavelength conversion particles 13 can be produced, for example, by using the sol-gel method (see Japanese Patent No. 5682609). Specifically, first, a quantum dot is prepared, and an appropriate amount of a metal alkoxide (1) such as tetraethoxysilane is added to the quantum dot, and is appropriately hydrolyzed, so that the surface of the quantum dot is metal alkoxide. Substitute with the hydrolyzate of (1). Such a liquid is referred to as an organic solvent A. On the other hand, a metal alkoxide (2) such as 3-mercaptopropyltrimethoxysilane is dispersed in the aqueous solution and partially hydrolyzed to obtain an aqueous solution B. Here, the metal alkoxide (2) is selected to have a slower hydrolysis rate than the metal alkoxide (1). Then, by mixing the organic solution A and the aqueous solution B, a layer of the metal alkoxide (2) is further formed on the surface of the quantum dot covered with the metal alkoxide (1). The quantum dots that have come into contact with water become hydrophilic due to the progress of hydrolysis of the metal alkoxide on the surface, and move to the water phase. At this time, the quantum dots form an aggregate. Since the metal alkoxide (2) near the surface has a slower hydrolysis rate than the metal alkoxide (1), it is possible that the alkoxide on the surface of the quantum dot is dehydrated and condensed at once when it moves to the aqueous phase, and becomes a large lump. prevent. An inorganic oxide layer such as a silica glass layer is further deposited on the aggregate in the aqueous phase. This can be performed by hydrolyzing a small amount of the metal alkoxide (3) in the alkaline region with a large amount of water and alcohol by the ordinary Stover method, and depositing it on the aggregate of quantum dots serving as nuclei. Thereby, the light wavelength conversion particles 13 can be obtained.

<<<< Other light wavelength conversion sheets >>>>
As shown in FIG. 3, the light wavelength conversion sheet may be a light wavelength conversion sheet 20 that further includes a light transmissive base material 21 that supports the light wavelength conversion layer 11, in addition to the light wavelength conversion layer 11. By providing the light transmissive base material 21, the strength of the light wavelength conversion sheet 20 can be increased. The light wavelength conversion sheet 20 has a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90% and / or an oxygen transmission rate of 23 ° C. and a relative humidity of 90% as a whole. Is 0.1 cm ³ / (m ² · 24h · atm) or more. The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 20 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 20. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more.

<< Light-transmissive substrate >>
The light transmissive substrate 21 is not particularly limited as long as it has light transmissivity, but has a function of protecting the quantum dots 15 from moisture and oxygen in order to further protect the quantum dots 15 from moisture and oxygen. Is preferred.

  The thickness of the light transmissive substrate 21 is not particularly limited, but is preferably 10 μm or more and 150 μm or less. If the thickness of the light-transmissive substrate is less than 10 μm, wrinkles and folds may occur during assembly and handling of the light wavelength conversion sheet, and if it exceeds 150 μm, it is suitable for weight reduction and thinning of the display. There is a possibility that there is no. A more preferable lower limit of the thickness of the light transmissive substrate 21 is 50 μm or more, and a more preferable upper limit thereof is 125 μm or less.

  The thickness of the light transmissive substrate 21 is obtained by photographing a cross section of the light transmissive substrate using a scanning electron microscope (SEM), a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). In the image, the thickness of the light-transmitting substrate is measured at 20 locations, and the average value of the thicknesses at the 20 locations is used.

  Examples of the constituent material of the light transmissive substrate 21 include polyester (eg, polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyether sulfone, polysulfone, polypropylene. , Polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethylmethacrylate, polycarbonate, polyurethane, or cycloolefin polymer (COP). The constituent material of the light-transmissive substrate 21 is preferably polyester (for example, polyethylene terephthalate or polyethylene naphthalate).

  The light transmissive base material 21 may be composed of a single base material, or may be a laminated base material composed of a plurality of base materials. Such a laminated base material may be composed of a plurality of layers composed of layers of the same kind of constituent material, or may be composed of a plurality of layers composed of layers of different kinds of constituent materials, depending on the application. Good.

  As shown in FIGS. 4 and 5, the light wavelength conversion sheet may be the light wavelength conversion sheet 30 including only the light wavelength conversion layer 31 including the lens portion 32. Since the light wavelength conversion layer 31 includes the lens portion 32, the light wavelength conversion sheet 30 has a lens function in addition to the light wavelength conversion function, so that it is possible to omit one lens sheet and further reduce the thickness. And reduction of manufacturing cost can be achieved.

The light wavelength conversion sheet 30 has a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90% and / or an oxygen transmission rate of 23 ° C. and a relative humidity of 90% as a whole. Is 0.1 cm ³ / (m ² · 24h · atm) or more. The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 30 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 30. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more. The light wavelength conversion layer 31 of the light wavelength conversion sheet 30 has a function of suppressing deterioration of the quantum dots 15.

  The lens portion 32 is a part of the light wavelength conversion sheet 30. Examples of the lens unit 32 include a lens unit having a light condensing property. The light exit surface 30A of the light wavelength conversion sheet 30 is the lens surface 32A of the lens portion 32. However, when the light wavelength conversion sheet includes a lens portion, either the light entrance surface or the light exit surface of the light wavelength conversion sheet is used. It should be the lens surface. In the present specification, the “lens surface” refers to a surface that exhibits a lens action (refraction action) in the lens portion.

  The lens unit 32 includes a plurality of unit lenses 33. As shown in FIGS. 3 and 4, the unit lenses 33 are arranged on the main body 33 having the same structure as the light wavelength conversion sheet 30 without any gap. As shown in FIG. 3, the unit lenses 33 extend linearly in a direction intersecting the arrangement direction AD of the unit lenses 33, and particularly linearly in the present embodiment. Further, in the present embodiment, the plurality of unit lenses 33 extend in parallel with each other. The longitudinal direction LD of the unit lens 33 is orthogonal to the arrangement direction AD of the unit lens 33 in the light wavelength conversion sheet 30.

  The unit lens may have a triangular prism shape, or may have a corrugated shape or a bowl shape such as a hemispherical shape. Specifically, the unit lens unit includes a unit prism unit, a unit cylindrical lens unit, a unit microlens unit, and the like. In the present embodiment, a triangular prism-shaped unit prism portion whose width becomes narrower toward the light output side will be described as the unit lens. A shape of a cross section (also referred to as a main cutting surface of the light wavelength conversion sheet) parallel to both the normal direction ND of the sheet surface of the body portion 34 of the light wavelength conversion sheet 30 and the arrangement direction AD of the unit lenses 33 shown in FIG. Has a triangular shape protruding toward the light output side. In particular, from the viewpoint of intensively improving the brightness in the front direction, the cross-sectional shape of the unit lens 33 on the main cutting surface is an isosceles triangular shape, and the apex angle located between the equal sides is the light emitting side surface 34A of the main body 34. Each unit lens 33 is configured so as to project from the light emitting side to the light emitting side.

  From the viewpoint of improving the light utilization efficiency, the unit lens 33 preferably has an apex angle of 80 ° or more and 100 ° or less, and more preferably has an apex angle of about 90 °. However, in consideration of damage to the tip of the unit lens when the light wavelength conversion sheet is wound, the tip of the unit lens 33 may be a curved surface.

  The dimensions of the light wavelength conversion sheet 30 can be set as follows, for example. First, as a specific example of the unit lens 33, the array pitch of the unit lenses 33 (corresponding to the width of the unit lenses 33 in the illustrated example) can be set to 10 μm or more and 200 μm or less. However, in recent years, the arraying of the unit lenses 33 is rapidly becoming finer, and it is preferable to set the arraying pitch of the unit lenses 33 to 10 μm or more and 50 μm or less. Further, the protruding height of the unit lens 33 from the main body 34 along the normal direction ND to the sheet surface of the light wavelength conversion sheet 30 can be set to 5 μm or more and 100 μm or less. Further, the apex angle of the unit lens 33 can be set to 60 ° or more and 120 ° or less.

  The light wavelength conversion sheet may be a light wavelength conversion sheet 40 that further includes an optical member 41 in addition to the light wavelength conversion layer 11, as shown in FIGS. 6 and 7. As shown in FIGS. 6 and 7, the light wavelength conversion sheet 40 includes a light wavelength conversion layer 11, an optical member 41 arranged on one side of the light wavelength conversion layer 11, a light wavelength conversion layer 11 and an optical member. An adhesive layer 42 for sticking 41 together is provided. Since the light wavelength conversion layer 11 and the optical member 41 are bonded together with the adhesive layer 42 unfolded, the light wavelength conversion layer 11 and the optical member 41 are integrated without an air layer. In the present embodiment, the optical member 41 is provided only on one side of the light wavelength conversion layer 11, but the optical members may be provided on both sides of the light wavelength conversion layer. In addition, in the present embodiment, the light wavelength conversion layer 11 and the optical member 41 are bonded to each other via the adhesive layer 42. However, the optical wavelength conversion layer composition is directly applied to the optical member to cure the light. The wavelength conversion layer and the optical member may be directly bonded.

  In the present specification, the term “optical member” refers to optical characteristics (for example, polarization, light refraction, light scattering, light reflection, light transmission, light absorption, light diffractiveness, optical rotatory power, etc.). It means a member having and is not particularly limited as long as it is a sheet (film) -shaped or plate-shaped member having optical characteristics. Examples of the optical member include a lens sheet, an optical plate such as a light guide plate and a light diffusion plate, a reflective polarization separation sheet, a polarizing plate, and the like. When the optical members are provided on both sides of the light wavelength conversion sheet, the optical members may be optical members having different optical characteristics. In this embodiment, the optical member 41 is a lens sheet including a light-transmissive base material 43 and a lens layer 44 provided on one surface of the light-transmissive base material 43 and having a plurality of unit lenses 45. An example will be described. The shape of the unit lens of the lens sheet may be a triangular prism shape, or may be a wavy shape or a bowl shape such as a hemispherical shape. Examples of the lens sheet having such a unit lens shape include a prism sheet, a lenticular lens sheet, and a microlens sheet.

The light wavelength conversion sheet 40 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or an oxygen transmission rate of 23 ° C. and a relative humidity of 90% as a whole. Is 0.1 cm ³ / (m ² · 24h · atm) or more. The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 40 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 40. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more.

<< Optical member >>
The optical member 41 as a lens sheet has a function of changing the traveling direction of incident light and emitting the light from the light emission side. In the present embodiment, as shown in FIG. 7, in addition to the function of concentrating the brightness in the front direction by concentrating the brightness in the front direction by changing the traveling direction of the incident light L3 and emitting the light L3 from the light exit side, It has a function (retroreflection function) of reflecting the incident light L4 and returning it to the light wavelength conversion layer 11 side. As described above, the light control sheet 41 includes the light transmissive base material 43 and the lens layer 44 provided on one surface of the light transmissive base material 43 and having the plurality of unit lenses 45.

<Light-transmissive substrate>
Since the light transmissive base material 43 is the same as the light transmissive base material 21, its description is omitted here.

<Lens layer>
The lens layer 44 includes a plurality of unit lenses 45, but also includes a sheet-shaped main body portion 46. The plurality of unit lenses 45 are arranged side by side on the light output side of the main body 46.

  The main body 46 functions as a sheet-shaped member that supports the unit lenses 45. As shown in FIG. 7, the unit lenses 45 are arranged on the light emitting side surface 46A of the main body 46 without any gap. Therefore, the light exit surface of the optical member control sheet 41 is formed by the lens surface 44A. On the other hand, as shown in FIG. 7, in the present embodiment, the main body portion 46 has a smooth surface serving as the light incident side surface of the lens layer 44 as the light incident side surface 46B facing the light exit side surface 46A. There is. Since the unit lens 45 is similar to the unit lens 33, the description thereof will be omitted here.

  The light wavelength conversion sheet may be a light wavelength conversion sheet 50 including a light wavelength conversion layer 11 and overcoat layers 51 and 52 that cover both surfaces of the light wavelength conversion layer 11, as shown in FIG. 8. In the present embodiment, the overcoat layers 51 and 52 are formed on both surfaces of the light wavelength conversion layer 11, but if the overcoat layer is formed on at least one surface of the light wavelength conversion layer, the light wavelength conversion layer is formed. It may not be formed on both surfaces of the layer 11. When the overcoat layer is provided only on one surface of the light wavelength conversion layer, a light transmissive base material may be provided on the other surface of the light wavelength conversion layer.

The light wavelength conversion sheet 50 has a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90% and / or an oxygen transmission rate of 23 ° C. and a relative humidity of 90% as a whole. Is 0.1 cm ³ / (m ² · 24h · atm) or more. The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 50 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 50. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more.

<< Overcoat layer >>
The overcoat layers 51 and 52 are layers that cover the surface of the light wavelength conversion layer 11 and are made of a resin and formed by coating. Other layers such as a light diffusion layer may be formed on the overcoat layers 51 and 52.

  The overcoat layers 51 and 52 are provided to prevent the light wavelength conversion layer 11 from being directly exposed to the atmosphere. By providing such overcoat layers 51 and 52 on at least one surface of the light wavelength conversion layer 11, the quantum dots 15 can be protected from moisture and oxygen, and the light transmissive base material is used as the light wavelength conversion layer. The thickness of the light wavelength conversion sheet can be made smaller than that provided on at least one surface of 11.

  The overcoat layers 51 and 52 may have some function other than the function of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere. Specifically, the overcoat layers 51 and 52 may be layers having at least one function such as antiblocking property, light diffusing property, antistatic property, and antireflection property. When the overcoat layers 51, 52 are layers having a function of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere and some other function, the overcoat layers 51, 52 have a certain function. Materials may be added.

  The thickness of the overcoat layers 51 and 52 is 0.1 μm or more and 100 μm or less from the viewpoint of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere and reducing the thickness of the light wavelength conversion sheet. Is preferred. The film thickness of the overcoat layer can be measured by the same method as the thickness of the light transmissive base material 21. The lower limit of the film thickness of the overcoat layers 51 and 52 is more preferably 1 μm or more, and the upper limit thereof is more preferably 50 μm or less.

  The overcoat layers 51 and 52 preferably have a hardness that provides a vertical force of 10 μN or more and / or a horizontal force of −5 μN or less in a scratch test. When the overcoat layers 51 and 52 have such hardness, the overcoat layers 51 and 52 are dense films, and therefore have a high ability to prevent the light wavelength conversion layer 11 from being exposed to the atmosphere. The vertical force and the horizontal force in the scratch test were measured using a nanoindentation device (product name “TI950 TriboIndenter”, manufactured by HYSITRON (Heiditron) Co., Ltd.) from the cross section of the overcoat layer to the inward direction of the overcoat layer. Corner: Ti037_110410 (12)) is pushed in by 50 nm and the depth is kept constant, and the vertical force (load) and the average of the horizontal force measured when the indenter is moved horizontally at a moving speed of 4 μm / min for 30 seconds. The average value of five average values of vertical force (5 times average value) and the average value of 5 average values of horizontal force (5 times average value) obtained by repeating the scratch test 5 times respectively. And The larger the vertical force and the smaller the horizontal force, the higher the hardness of the overcoat layers 51 and 52. From the viewpoint of enhancing the ability to prevent the light wavelength conversion layer 11 from being exposed to the atmosphere, the vertical force in the scratch test of the overcoat layers 51 and 52 is more preferably 15 μN or more, and the horizontal force is more preferably −8 μN or less. preferable.

  The overcoat layers 51, 52 are not particularly limited as long as they have the above-mentioned hardness, but for example, a (meth) acrylate compound, an epoxy compound, a combination of an isocyanate and a polyol, a metal alkoxide, a silicon-containing resin, a water-soluble polymer, Alternatively, it can be formed by using an overcoat layer composition containing a mixture thereof. Among these, the overcoat layers 51 and 52 are zinc acrylate, a hydrolysis product of an alkoxysilane, polyvinyl alcohol, polysilazane, or these from the viewpoint of preventing the light wavelength conversion layer 11 from being directly exposed to the atmosphere. It is preferably formed using a composition for an overcoat layer containing a mixture.

  The light wavelength conversion sheets 20, 30, 40, and 50 are also one of the ones of the light wavelength conversion sheets 20, 30, and 40 before and after the durability test in which the light wavelength conversion sheets are left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours. When the central part of the surface is irradiated with a predetermined amount of light whose wavelength is converted by the quantum dots, and the brightness of the light emitted from the central part of the other surface of the light wavelength conversion sheet 20, 30, 40, 50 is measured. , The other of the light wavelength conversion sheets 20, 30, 40, 50 after the durability test with respect to the brightness of the light emitted from the central portion of the other surface of the light wavelength conversion sheets 20, 30, 40, 50 before the durability test The change rate of the brightness of the light emitted from the central portion of the surface is preferably within ± 10%, more preferably within ± 5%. Further, also in the light wavelength conversion sheets 20, 30, 40, and 50, when a durability test of leaving the light wavelength conversion sheet for 50 hours in an environment of 60 ° C. and a relative humidity of 90% is performed, the light wavelength conversion sheet 20 after the durability test, The deterioration width of the peripheral edge portions of 30, 40, and 50 is preferably 5 mm or less, and more preferably 3 mm or less.

<<< Method of manufacturing light wavelength conversion sheet >>>
The light wavelength conversion sheet 10 can be manufactured, for example, as follows. FIG. 9 is a schematic manufacturing process diagram of the light wavelength conversion sheet according to the present embodiment. First, as shown in FIG. 9A, a light wavelength containing a curable binder resin precursor 56 and the light conversion wavelength particles 13 dispersed in the curable binder resin precursor 56 on one surface of the base material 55. The composition for the conversion layer is applied and dried to form a coating film 57 of the composition for the light wavelength conversion layer. The base material 52 may be a light transmissive base material, but need not be a light transmissive base material. The composition for the light wavelength conversion layer preferably contains a polymerization initiator.

  The polymerization initiator is a component that is decomposed by light or heat to generate radicals or ionic species to start or proceed with the polymerization (crosslinking) of the curable resin precursor. The polymerization initiator used in the composition for the light wavelength conversion layer includes a photopolymerization initiator (for example, a photoradical polymerization initiator, a photocationic polymerization initiator, a photoanionic polymerization initiator), a thermal polymerization initiator (for example, a thermal radical). Polymerization initiator, thermal cationic polymerization initiator, thermal anionic polymerization initiator), or a mixture thereof.

  Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, thioxanthone, and the like.

  Examples of commercially available photoradical polymerization initiators include, for example, IRGACURE 184, IRGACURE 369, IRGACURE 379, IRGACURE 651, IRGACURE 819, IRGACURE 907, IRGACURE 2959, IRGACURE OXE 01, Lucilin TPO (all of which are manufactured by BASF Japan 9). ADEKA), SPEEDCURE EMK (Nippon Sebel Hegner), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.) and the like.

  Examples of the cationic photopolymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, and the like. Examples of commercially available photocationic polymerization initiators include Adeka Optomer SP-150 and Adeka Optomer SP-170 (both manufactured by ADEKA).

  Examples of the thermal radical polymerization initiator include peroxides and azo compounds. Among these, polymer azo initiators composed of polymer azo compounds are preferable. Examples of the polymeric azo initiator include those having a structure in which a plurality of units such as polyalkylene oxide and polydimethylsiloxane are bonded via an azo group.

  Examples of the polymer azo initiator having a structure in which a plurality of units such as polyalkylene oxide are bonded via the azo group include, for example, polycondensation products of 4,4′-azobis (4-cyanopentanoic acid) and polyalkylene glycol. Alternatively, a polycondensate of 4,4′-azobis (4-cyanopentanoic acid) and polydimethylsiloxane having a terminal amino group may be used.

  Examples of the peroxide include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, peroxy ester, diacyl peroxide, peroxydicarbonate and the like.

  Commercially available thermal radical polymerization initiators include, for example, perbutyl O, perhexyl O, perbutyl PV (all manufactured by NOF CORPORATION), V-30, V-501, V-601, VPE-0201. , VPE-0401, VPE-0601 (all manufactured by Wako Pure Chemical Industries, Ltd.) and the like.

  Examples of the thermal cationic polymerization initiator include various onium salts such as quaternary ammonium salt, phosphonium salt, and sulfonium salt. Examples of commercially available thermal cationic polymerization initiators include, for example, Adeka Opton CP-66, Adeka Opton CP-77 (all manufactured by ADEKA), Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L ( Examples include Sanshin Chemical Industry Co., Ltd.), CI series (Nippon Soda Co., Ltd.) and the like.

  Then, as shown in FIG. 9 (B), the coating film 57 of the composition for a light wavelength conversion layer is irradiated with ionizing radiation or heated to cure the coating film 57, and the light wavelength conversion layer. To form.

  Finally, as shown in FIG. 9C, the base material 55 is peeled from the light wavelength conversion layer 11. Thereby, the light wavelength conversion sheet 10 including only the light wavelength conversion layer 11 is obtained.

  The light wavelength conversion sheet 20 shown in FIG. 3 can be obtained by using a light transmissive base material as the base material 55 and leaving the base material 55 as it is without peeling after the formation of the light wavelength conversion layer 11.

  The light wavelength conversion sheet 30 shown in FIG. 4 can be formed by, for example, a drum printing system method (DPS method). That is, the composition for the light wavelength conversion layer is coated and filled in a rotating molding die having a concave portion having a shape opposite to the shape of the unit lens 33, and then the base material 55 is supplied to the molding surface to form The composition for light wavelength conversion layer is pressed onto a molding die from above. Then, in the pressed state, the composition for light wavelength conversion layer is irradiated with ionizing radiation such as ultraviolet rays through the base material 51, or heat is applied to the composition for light wavelength conversion layer to form the composition for light wavelength conversion layer. Harden the object. Then, the cured composition for light wavelength conversion layer is peeled off from the molding die that rotates together with the substrate 55. As a result, the light wavelength conversion layer 31 having the lens portion 32 is formed on the base material 55. Finally, the base material 51 is peeled off from the light wavelength conversion layer 31. Thereby, the light wavelength conversion sheet 30 including only the light wavelength conversion layer 31 having the lens portion 32 is obtained.

  In the light wavelength conversion sheet 40 shown in FIG. 6, after forming the light wavelength conversion layer 11, the optical member 41 is provided on the surface of the light wavelength conversion layer 11 opposite to the surface on the base material 55 side via the adhesive layer 42. It can be obtained by bonding and then peeling the base material 55 from the light wavelength conversion layer 11. When the base material 51 is a light transmissive base material, the base material 55 may be left as it is without being peeled off. Further, without using the adhesive layer 42, the composition for the light wavelength conversion layer is directly applied to the surface of the light transmissive base material 43 of the optical member 41 opposite to the surface on the lens layer 44 side. The composition for light wavelength conversion layer may be cured by irradiating the composition for light wavelength irradiation or by applying heat to the composition for light wavelength conversion layer. In this case, the optical member serves as the base material. Further, the optical member 41 may be arranged on the application surface of the coating film 53 of the composition for a light wavelength conversion layer applied on the base material 55, and then the coating film 57 may be cured. The base material 55 may be peeled off after curing. When the optical members are attached to both surfaces of the light wavelength conversion layer, the optical member is attached to the surface (first surface) opposite to the base material side surface of the light wavelength conversion layer via the adhesive layer. Before or after bonding, the base material is peeled from the light wavelength conversion layer, and after the base material is peeled, an adhesive layer is provided on the second surface of the light wavelength conversion layer opposite to the first surface. By bonding an optical member different from the above optical member, the optical member may be bonded to both surfaces of the light wavelength conversion layer.

  The light wavelength conversion sheet 50 shown in FIG. 8 is obtained by applying the composition for an overcoat layer on at least one surface of the light wavelength conversion sheet 10 to form a coating film of the composition for an overcoat layer. Can be formed by curing.

  The light wavelength conversion sheet 50 can also be formed by the following method. First, the composition for an overcoat layer is applied to one surface of two base materials to form a coating film of the composition for an overcoat layer. After forming the coating film, the coating film of each composition for overcoat layer is irradiated with ionizing radiation or heated to form an overcoat layer. After forming the overcoat layer, the composition for light wavelength conversion layer is applied on the overcoat layer formed on one of the base materials to form a coating film of the composition for light wavelength conversion layer. Next, the other base material is arranged on the coating film of the composition for light wavelength conversion layer so that the coating film of the composition for light wavelength conversion layer is in contact with the overcoat layer formed on the other base material. Then, in this state, the coating film of the composition for a light wavelength conversion layer is irradiated with ionizing radiation or heated to form a light wavelength conversion layer, and a light wavelength conversion layer and an overcoat layer are formed. Integrate. Finally, if both base materials are peeled off, the light wavelength conversion sheet 50 is obtained.

According to the present embodiment, the light wavelength conversion sheet 10, 20, 30, 40, 50 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or a light wavelength. Since the oxygen permeability of the conversion sheets 10, 20, 30, 40, 50 at 23 ° C. and relative humidity of 90% is 0.1 cm ³ / (m ² · 24 h · atm) or more, the light transmissive substrate. And a barrier film composed of a barrier layer is not provided. Therefore, pinholes and cracks due to the barrier film do not occur, and thus dot-like luminance defects can be suppressed. Further, in the light wavelength conversion sheets 10, 20, 30, 40, and 50, since the light wavelength conversion layers 11 and 31 have a deterioration suppressing function of the quantum dots 15, even if the quantum dots are not provided, 15 deterioration can be suppressed. Furthermore, since the light wavelength conversion sheets 10, 20, 30, 40, and 50 do not include the barrier film, it is possible to reduce the thickness and the manufacturing cost.

Usually, the light wavelength conversion sheet is cut into a desired size with the barrier films provided on both sides of the light wavelength conversion layer, so that the side surface of the cut light wavelength conversion sheet does not have a barrier film and is exposed. are doing. Therefore, the quantum dots existing in the peripheral portion of the light wavelength conversion sheet are more likely to deteriorate than the quantum dots existing in the central portion of the light wavelength conversion sheet. On the other hand, according to the present embodiment, since the optical wavelength conversion particles 13 in which the quantum dots 15 are wrapped with the barrier particles 16 are used, the quantum dots 15 can be protected from moisture and oxygen. As a result, the light wavelength conversion sheet 10, 20, 30, 40, 50 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or 23 ° C. and a relative humidity of 90. Even if the oxygen transmission rate in% is 0.1 cm ³ / (m ² · 24h · atm) or more, the peripheral portions 10C, 20C, 30C, 40C of the light wavelength conversion sheets 10, 20, 30, 40, 50 , 50C (see FIGS. 1, 3, 5, 7, and 8), the deterioration of the quantum dots 15 can be suppressed. Further, according to the present embodiment, since the quantum dots 15 are wrapped with the barrier particles 16, it is possible to impart the deterioration suppressing function of the quantum dots 15 to the light wavelength conversion layers 11 and 31.

Further, according to the present embodiment, the light wavelength conversion particles 13 in which the quantum dots 15 are wrapped with the barrier particles 16 are used to suppress the deterioration of the quantum dots 15, so that the light wavelength conversion sheets 10, 20, 30, The water vapor permeability at 40 ° C. and 90% relative humidity at 40 and 50 is 0.1 g / (m ² · 24 h) or more and / or the oxygen permeability at 23 ° C. and 90% relative humidity is 0.1 cm ³ / ( Since it is not necessary to separately provide a barrier film even if the thickness is more than m ² · 24h · atm), a single layer like the light wavelength conversion sheets 10 and 30 can be used.

According to the present embodiment, the light wavelength conversion sheet 10, 20, 30, 40, 50 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more and / or 23 ° C. at 40 ° C. and a relative humidity of 90%. Even if the oxygen transmission rate at a relative humidity of 90% is 0.1 cm ³ / (m ² · 24h · atm) or more, the light wavelength conversion sheet 10, 20, 30, 40, 50 is at 60 ° C. and a relative humidity. Before and after the durability test of leaving it in an environment of 90% for 500 hours, the durability test against the brightness of the light emitted from the central portion of the surface of the light wavelength conversion sheet 10, 20, 30, 40, 50 before the durability test When the rate of change in the brightness of the light emitted from the central portion of the surface of the subsequent light wavelength conversion sheets 10, 20, 30, 40, 50 is within ± 10%, the light wavelength conversion sheets 10, 20, The center of 30, 40, 50 The deterioration can be suppressed. Further, in this case, the deterioration width of the peripheral portion of the light wavelength conversion sheet 10, 20, 30, 40, 50 after the durability test of leaving it in an environment of 60 ° C. and relative humidity of 90% for 500 hours is set to 5 mm or less. can do. This makes it possible to suppress the deterioration of the central portion and the peripheral portion of the light wavelength conversion sheets 10, 20, 30, 40, 50 without providing the barrier film.

  As described above, since the side surface is exposed in the conventional light wavelength conversion sheet, the quantum dots on the peripheral portion of the light wavelength conversion sheet are deteriorated. When the quantum dots on the peripheral portion of the light wavelength conversion sheet deteriorate, the wavelength conversion efficiency decreases. One of the reasons for this is that when the light from the light source is incident on the light wavelength conversion sheet, the tint of the light emitted from the peripheral portion of the light wavelength conversion sheet is It may be more noticeable than the color. On the other hand, in the present embodiment, by using the light wavelength conversion particles 13 in which the quantum dots 15 are surrounded by the barrier particles 16, the quantum existing in the peripheral portions of the light wavelength conversion sheets 10, 20, 30, 40, 50. Since the deterioration of the dots 15 can be suppressed, it is possible to suppress the tint of the light emitted from the peripheral portions of the light wavelength conversion sheets 10, 20, 30, 40, 50 from being more prominent than the tint of the central portion. .

  As described above, when the barrier film is provided, pinholes and cracks are generated in the barrier film, water and oxygen may penetrate into the light wavelength conversion sheet from there, and the quantum dots may deteriorate. The cracks in the barrier film are particularly likely to occur when the light wavelength conversion sheet is bent. On the other hand, in the present embodiment, since the barrier film is not provided, it is possible to deal with foldable.

  According to the present embodiment, since it is not necessary to separately provide a barrier film, it is possible to support a mobile product (a portable computer terminal device including a so-called smartphone device) having a strict requirement for thickness.

  According to this embodiment, since the light wavelength conversion sheets 10, 20, 30, 40, and 50 include the light scattering particles 14, green light emission can be preferentially enhanced over red light emission. The reason for this is not clear, but the light-scattering particles impede energy transfer from the first quantum dot that converts blue light to green light to the second quantum dot that converts blue light to red light. It is considered that this is because the green light emission, which was originally deactivated by the energy transfer, reaches the light emission process without being deactivated, resulting in an increase in green light emission.

  Conventionally, the thickness of a light wavelength conversion sheet provided with barrier films on both sides of a light wavelength conversion layer is about 300 μm, so it is difficult to bond the light wavelength conversion sheet and an optical member such as a lens sheet, and they are arranged separately. It had been. Therefore, the assembly work of the backlight device becomes complicated, and a foreign substance may enter between the light wavelength conversion sheet and the light control sheet, and an air interface exists between the light wavelength conversion sheet and the optical member. As a result, the light utilization efficiency may be reduced. On the other hand, the light wavelength conversion sheet according to the present embodiment does not require a barrier film, and thus can be extremely thin. Therefore, like the light wavelength conversion sheet 40, the light wavelength conversion layer and the optical member can be bonded together. As a result, as compared with the case where the light wavelength conversion sheet and the optical member are separately arranged, the work of assembling the backlight device is facilitated, and a foreign substance may enter between the light wavelength conversion layer and the light control sheet. Can be suppressed, and further space saving and simplification of members can be achieved.

  The light wavelength conversion sheets 10, 20, 30, 40 and 50 can be used by incorporating them in a backlight device and an image display device. Hereinafter, an example in which the light wavelength conversion sheet 10 is incorporated in a backlight device and an image display device will be described. 10 is a schematic configuration diagram of an image display device including the backlight device according to the present embodiment, FIG. 11 is a perspective view of the lens sheet shown in FIG. 10, and FIG. 12 is another backlight according to the present embodiment. It is a schematic block diagram of a light device.

<<< Image display device >>>
The image display device 60 shown in FIG. 10 includes a backlight device 70 and a display panel 110 arranged on the light emitting side of the backlight device 70. The image display device 60 has a display surface 60A for displaying an image. In the image display device 60 shown in FIG. 10, the surface of the display panel 110 is the display surface 60A.

  The backlight device 60 illuminates the display panel 110 in a planar manner from the back side. The display panel 110 functions as a shutter that controls transmission or blocking of light from the backlight device 60 for each pixel, and is configured to display an image on the display surface 60A.

<< Display panel >>
A display panel 110 shown in FIG. 10 is a liquid crystal display panel, and includes a polarizing plate 111 arranged on the light incident side, a polarizing plate 112 arranged on the light emitting side, and between the polarizing plate 111 and the polarizing plate 112. And the liquid crystal cell 113 arranged. The polarizing plates 111 and 112 decompose the incident light into two orthogonal linearly polarized light components (S-polarized light and P-polarized light) and oscillate in one direction (direction parallel to the transmission axis) (for example, P-polarized light component). It has a function of transmitting polarized light and absorbing a linearly polarized light component (for example, S-polarized light) vibrating in the other direction (direction parallel to the absorption axis) orthogonal to the one direction.

  The liquid crystal cell 113 is configured so that a voltage can be applied to each area forming one pixel. Then, the alignment direction of the liquid crystal molecules in the liquid crystal cell 113 changes depending on whether or not a voltage is applied. As an example, the linearly polarized light component in a specific direction transmitted through the polarizing plate 111 arranged on the light incident side rotates its polarization direction by 90 ° when passing through the liquid crystal cell 113 to which a voltage is applied, while When passing through the liquid crystal cell 113 to which no voltage is applied, the polarization direction is maintained. In this case, depending on whether or not a voltage is applied to the liquid crystal cell 113, the linearly polarized light component that has passed through the polarizing plate 111 and vibrates in a specific direction may be transmitted to the polarizing plate 112 or may be absorbed and blocked by the polarizing plate 112. it can. In this way, the display panel 110 is configured so that transmission or blocking of light from the backlight device 70 can be controlled for each pixel. Note that details of the liquid crystal display panel are described in various publicly known documents (for example, “Flat Panel Display Encyclopedia (Tatsuo Uchida, Hiraki Uchiike)”, published by the 2001 Industrial Research Committee, and no more here. The detailed description of is omitted.

<< Backlight device >>
The backlight device 70 shown in FIG. 10 is configured as an edge light type backlight device, and includes a light source 75, an optical plate 80 as a light guide plate disposed on the side of the light source 75, and a light exit side of the optical plate 80. The light wavelength conversion sheet 10 disposed on the light wavelength conversion sheet 10, the lens sheet 85 disposed on the light emission side of the light wavelength conversion sheet 10, the lens sheet 90 disposed on the light emission side of the lens sheet 85, and the light emission side of the lens sheet 90. The reflective polarization separation sheet 95 is provided, and the reflection sheet 100 is provided on the side opposite to the light exit side of the optical plate 80. The backlight device 70 includes the optical plate 80, the lens sheets 85 and 90, the reflective polarization separation sheet 95, and the reflective sheet 100, but these sheets and the like may not be provided. In the present specification, the “light emitting side” means the side from which the light emitted from the backlight device is emitted from each member.

  The backlight device 70 has a light emitting surface 70A that emits light in a planar shape. In the backlight device 70 shown in FIG. 10, the light emitting surface of the reflective polarization separation sheet 95 is the light emitting surface 70A of the backlight device 70.

  The surface of the light wavelength conversion sheet 10 on the optical plate 80 side is the light entrance surface 10A, and the surface of the light wavelength conversion sheet 10 on the lens sheet 85 side is the light exit surface 10B.

<Light source>
The light source 75 can be configured in various forms such as a fluorescent lamp such as a linear cold cathode fluorescent lamp, a point light emitting diode (LED), an incandescent lamp, and the like. In the present embodiment, the light source 75 is composed of a large number of point-like light emitting elements arranged in a line on the light incident surface 80C side of the optical plate 60 described later, specifically, a large number of light emitting diodes (LEDs). ,It is configured.

  Since the light wavelength conversion sheet 10 is arranged in the backlight device 70, the light source 75 can use only a light emitter that emits light in a single wavelength range. For example, as the light source, only a blue light emitting diode that emits blue light with high color purity can be used.

<Optical plate>
The optical plate 80 as a light guide plate is formed in a quadrangular shape in plan view. The optical plate 80 extends between a light emitting surface 80A formed by one main surface on the display panel 110 side, a back surface 80B formed by the other main surface facing the light emitting surface 80A, and between the light output surface 80A and the back surface 80B. And a side surface. Of the side surfaces, the side surface on the light source 75 side is a light incident surface 80C that receives light from the light source 75. Light that has entered the optical plate 80 from the light incident surface 80C is guided inside the optical plate in a direction (light guide direction) that connects the light incident surface 80C and the opposite surface that faces the light incident surface 80C, and the light exit surface It is emitted from 80A.

  When the light-incident surface 10A of the light wavelength conversion sheet 10 is an uneven surface due to an anti-blocking agent or the like, the light-exiting surface 80A is in optical contact with a part of the light-incident surface 10A (for example, a convex portion). Further, it is preferable to be separated from other portions (for example, concave portions) of the light incident surface 10A. In this case, the gap between the light exit surface 80A and the other part of the light entrance surface 10A is an air layer. By providing this air layer, even when the light wavelength conversion sheet 10 is fixed to the light exit surface 60A so that the light exit surface 80A and the light entrance surface 10A are in optical contact, the light wavelength on the light exit surface 80A is fixed. Since it is possible to prevent the conversion sheet 10 from sticking, it is possible to suppress the formation of a wetout at the interface between the light wavelength conversion sheet 10 and the optical plate 80. In the present specification, "optically close contact" means a state in which the light exit surface of the optical plate and a part of the light entrance surface of the light wavelength conversion sheet are in close contact with each other without forming an air layer therebetween. Further, the state where the light wavelength conversion sheet is not attached to the light emitting surface of the optical plate means that the light is emitted from the light emitting surface of the optical plate in the plane direction of the light emitting surface when the fixation of the light wavelength conversion sheet and the optical plate is released. This means that the wavelength conversion sheet can be moved.

  As a material forming the optical plate 80, a material that is widely used as a material for an optical sheet incorporated in an image display device, has excellent mechanical properties, optical properties, stability, processability, and the like, and is inexpensive and available. For example, a transparent resin mainly containing one or more of acrylic resin, polystyrene, polycarbonate, polyethylene terephthalate, polyacrylonitrile, and a reactive resin of epoxy acrylate or urethane acrylate (ionizing radiation curable resin, etc.) are preferably used. Can be done. If necessary, a light diffusing material having a function of diffusing light may be added to the optical plate 60. As the light diffusion material, for example, particles made of a transparent substance such as silica (silicon dioxide), alumina (aluminum oxide), acrylic resin, polycarbonate resin, and silicone resin having an average particle diameter of 0.5 μm or more and 100 μm or less may be used. it can.

<Lens sheet>
As shown in FIG. 11, the lens sheets 85 and 90 have the same configuration as the optical member 41. That is, the lens sheets 85 and 90 each include a light-transmissive base material 86 and a lens layer 87 that is provided on one surface of the light-transmissive base material 86 and that has a plurality of unit lenses 88. The unit 87 includes a unit lens 88 and a sheet-shaped main body 89. The light transmissive base material 86, the lens layer 87, the unit lens 88, and the main body portion 89 are the same as the light transmissive base material 43, the lens layer 44, the unit lens 45, and the main body portion 46 of the optical member 41, and therefore, here, The description will be omitted.

  As can be understood from FIG. 10, the arrangement direction of the unit lenses 88 of the lens sheet 85 and the arrangement direction of the unit lenses 88 of the lens sheet 90 intersect, and more specifically, are orthogonal to each other.

<Reflective polarization separation sheet>
The reflection-type polarization separation sheet 95 transmits only the first linearly polarized light component (for example, P-polarized light) of the light emitted from the lens sheet 85, and the second linearly polarized light orthogonal to the first linearly polarized light component. It has a function of reflecting a polarized component (for example, S polarized light) without absorbing it. The second linearly polarized light component reflected by the reflective polarization separation sheet 95 is reflected again, and the polarization is eliminated (a state in which both the first linearly polarized light component and the second linearly polarized light component are included), It is incident on the reflective polarization separation sheet 95 again. Therefore, the reflective polarization separation sheet 95 transmits the first linearly polarized light component of the re-incident light, and the second linearly polarized light component orthogonal to the first linearly polarized light component is reflected again. Hereinafter, by repeating the above process, about 70 to 80% of the light emitted from the lens sheet 75 is emitted as the light source light which has become the first linearly polarized light component. Therefore, by making the polarization direction of the first linearly polarized light component (transmission axis component) of the reflective polarization separation sheet 95 and the transmission axis direction of the polarizing plate 111 of the display panel 110 coincide with each other, the light emitted from the backlight device 50 is emitted. Are all available on the display panel 110 for image formation. Therefore, even if the light energy input from the light source 75 is the same, it is possible to form an image with higher brightness than in the case where the reflective polarization separation sheet 95 is not arranged, and the energy use efficiency of the light source 75 is also improved. improves. In particular, the light reflected by the reflective polarization separation sheet 95 can be wavelength-converted by the light wavelength conversion sheet 10. Therefore, the wavelength conversion efficiency of the light wavelength conversion sheet 10 can be further increased by disposing the reflective polarization separation sheet 95. Therefore, it is possible to expect further improvement in the light use efficiency.

  As the reflective polarization separation sheet 95, “DBEF” (registered trademark) available from 3M Company can be used. In addition to “DBEF”, a high-brightness polarizing sheet “WRPS”, a wire grid polarizer or the like available from Shinwha Intertek can be used as the reflective polarization separation sheet 95.

<Reflective sheet>
The reflection sheet 100 has a function of reflecting the light leaked from the back surface 80B of the optical plate 80 and making it enter the optical plate 80 again. The reflection sheet 100 is composed of a white scattering reflection sheet, a sheet made of a material having a high reflectance such as metal, a sheet including a thin film (for example, a metal thin film) made of a material having a high reflectance as a surface layer, and the like. obtain. The reflection on the reflection sheet 85 may be regular reflection (specular reflection) or diffuse reflection. When the reflection on the reflection sheet 85 is diffuse reflection, the diffuse reflection may be isotropic diffuse reflection or anisotropic diffuse reflection.

<< Other backlight devices >>
The backlight device incorporating the light wavelength conversion sheet 10 may be a direct type backlight device as shown in FIG. The backlight device 120 shown in FIG. 12 includes a light source 75, an optical plate 121 that receives light from the light source 75 and functions as a light diffusing plate, and a light wavelength conversion sheet 10 that is arranged on the light output side of the optical plate 121. A lens sheet 85 arranged on the light emitting side of the light wavelength conversion sheet 10 and a reflective polarization separation sheet 95 arranged on the light emitting side of the lens sheet 85 are provided. In the present embodiment, the light source 75 is arranged directly below the optical plate 121, not on the side of the optical plate 121. In FIG. 12, the members designated by the same reference numerals as those in FIG. 10 are the same as the members shown in FIG. 10, and thus the description thereof will be omitted. The backlight device 120 does not include the reflective sheet 100.

<Optical plate>
The optical plate 121 as a light diffusing plate is formed in a quadrangular shape in plan view. The optical plate 121 has a light incident surface 121A formed by one main surface on the light source 75 side and a light output surface 121B formed by the other main surface on the light wavelength conversion sheet 10 side. Light that has entered the optical plate 121 from the light incident surface 121A is scattered in the optical plate 121 and emitted from the light exit surface 101B.

  The optical plate 121 is not particularly limited as long as it can scatter the light from the light source 75, and examples thereof include a plate in which light scattering particles are dispersed in a transparent material. The transparent material is not particularly limited, but examples thereof include transparent resin and inorganic glass. As the transparent resin, a transparent thermoplastic resin is preferably used because it is easy to mold. The transparent thermoplastic resin is not particularly limited, but examples thereof include polystyrene resin, styrene-methyl methacrylate copolymer resin, styrene-methacrylic acid copolymer resin, styrene-maleic anhydride copolymer resin. , Methacrylic resin, acrylic resin, polycarbonate resin, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), AS resin (acrylonitrile-styrene copolymer resin), polyolefin resin (polyethylene resin, polypropylene resin, etc.) and the like. . One of these may be used, or two or more of these may be mixed and used.

<Light scattering particles>
The average particle diameter of the light scattering particles is, for example, preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less. If it is less than 0.5 μm, the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient, and it is necessary to increase the amount of the light scattering particles added in order to obtain sufficient light scattering properties. On the other hand, when it exceeds 30 μm, the light-scattering property becomes poor and the film thickness becomes close to the film thickness of the light wavelength conversion layer, so that it becomes difficult to stabilize the film formation. The average particle size of the light-scattering particles can be measured by the same method as the above-mentioned quantum dot.

  The average particle size of the light-scattering particles is preferably 10 times or more and 20,000 times or less, and more preferably 10 to 5000 times the average particle size of the quantum dots described above. If it is less than 10 times, sufficient light scattering properties may not be obtained in the light scattering plate, and if it exceeds 20,000 times, the light scattering performance of the light scattering plate will be excellent. It is easy to significantly reduce the light transmittance.

  The light scattering particles may be particles made of an organic material or particles made of an inorganic material. The organic material forming the light-scattering particles is not particularly limited, and examples thereof include polyester, polystyrene, melamine resin, (meth) acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzoguanamine resin, benzoguanamine / formaldehyde condensation resin. , Polycarbonate, polyethylene, polyolefin and the like. Among them, a crosslinked acrylic resin is preferably used. The inorganic material forming the light-scattering particles is not particularly limited, and examples thereof include inorganic oxides such as silica, alumina, titania, tin oxide, antimony-doped tin oxide (ATO), and zinc oxide fine particles. . Among them, silica and / or alumina are preferably used.

  In the present embodiment, an example in which the light wavelength conversion sheet 10 is incorporated into the backlight devices 70 and 120 has been described, but instead of the light wavelength conversion sheet 10, the light wavelength conversion sheets 20, 30, and 40 are used as backlights. It may be incorporated into the device 70, 120. When incorporating the light wavelength conversion sheets 30 and 40 into the backlight devices 70 and 120, the lens sheet 85 can be omitted because the lens portion 32 and the optical member 41 replace the lens sheet 85. The light wavelength conversion sheets 30 and 40 are arranged so that the lens portion 32 and the optical member 41 side are on the lens sheet 90 side.

[Second Embodiment]
Hereinafter, a light wavelength conversion sheet, a backlight device, and an image display device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 13 is a schematic configuration diagram of the light wavelength conversion sheet according to the present embodiment, and FIGS. 14 and 15 are schematic manufacturing process diagrams of the light wavelength conversion sheet according to the present embodiment.

<<< Light wavelength conversion sheet >>
The light wavelength conversion sheet 130 shown in FIG. 13 includes a light wavelength conversion layer 131, light transmissive base materials 132 and 133 provided on both surfaces of the light wavelength conversion layer 131, and light in the light transmissive base materials 132 and 133. The light diffusion layers 134 and 135 are provided on the side opposite to the surface on the wavelength conversion layer 131 side. In the light wavelength conversion sheet 130, the surfaces of the light diffusion layers 134 and 135 form the surfaces 130A and 130B of the light wavelength conversion sheet 130. The light wavelength conversion sheet 130 includes the light transmissive base materials 132 and 133, but does not include a barrier layer, and thus does not include a light transmissive base material and a barrier film including the barrier layer. The light wavelength conversion sheet 130 has a structure of light diffusion layer 134 / light transmissive base material 132 / light wavelength conversion layer 131 / light transmissive base material 133 / light diffusion layer 135. The structure of the light wavelength conversion sheet is not particularly limited as long as it has

The light wavelength conversion sheet 130 has a water vapor transmission rate of 0.1 g / (m ² · 24h) or more at 40 ° C. and a relative humidity of 90% and / or an oxygen transmission rate of 23 ° C. and a relative humidity of 90% as a whole. Is 0.1 cm ³ / (m ² · 24h · atm) or more. The water vapor transmission rate and the oxygen transmission rate are measured by the same method as in the first embodiment.

The water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet 130 may be 1 g / (m ² · 24 h) or more, and at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet 130. May have an oxygen permeability of 1 cm ³ / (m ² · 24h · atm) or more.

  Before and after the durability test in which the light wavelength conversion sheet 130 is left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours, the quantum dots 137 perform wavelength conversion on the entire one surface 130A of the light wavelength conversion sheet 130. When the brightness of the light emitted from the central portion of the other surface 130B, which is the surface opposite to the surface 130A of the light wavelength conversion sheet 130, is measured by irradiating the light wavelength The change rate of the luminance of the light emitted from the central portion of the surface 130B of the light wavelength conversion sheet 130 after the durability test with respect to the luminance of the light emitted from the central portion of the surface 130B of the conversion sheet 130 is within ± 10%. It is preferably within ± 5%.

  When the light wavelength conversion sheet 130 is subjected to a durability test in which it is left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours, the deterioration width of the peripheral portion of the light wavelength conversion sheet 130 after the durability test is 5 mm or less. Is preferably 3 mm or less, and more preferably 3 mm or less.

<<< Light wavelength conversion layer >>>
The light wavelength conversion layer 131 includes, for example, a binder resin 136 and quantum dots 137 dispersed in the binder resin 136. The light wavelength conversion layer 131 preferably further contains light scattering particles 138. Further, since the light wavelength conversion sheet 131 has the content of the specific element in the light wavelength conversion layer measured by X-ray fluorescence analysis as 0.5 mass% or more as described later, the deterioration of the quantum dots 137. Has a suppressing function.

  In the light wavelength conversion layer 131, one or more elements selected from the group consisting of sulfur, phosphorus, and nitrogen in the light wavelength conversion layer 131 measured by fluorescent X-ray analysis (XRF) (hereinafter, this element is The content of “specific element”) is 0.5 mass% or more. When the content of the specific element is less than 0.5% by mass, deterioration of the quantum dots may not be suppressed. When the specific element is composed of two or three elements, the content of the specific element in the present specification means the total content of the two or three elements. To do. The content of the specific element can be measured by using a fluorescent X-ray analyzer (product name “EDX-800HS”, manufactured by Shimadzu Corporation). The lower limit of the content of the specific element in the light wavelength conversion layer 11 measured by fluorescent X-ray analysis (XRF) is preferably 0.5% by mass or more, and the upper limit of the content of the specific element is 20. It is preferably not more than 10% by mass, more preferably not more than 10% by mass. If the content of the specific element exceeds 20% by mass, sufficient curing may not be performed when the light wavelength conversion layer is formed.

  Although the specific element is mainly contained in the binder resin 136, it may be contained in the quantum dots 137. In this case, in the quantum dot non-containing region of the light wavelength conversion layer 131, the specific element is attached to the electron microscope. By performing elemental analysis using an energy dispersive X-ray spectroscopic analyzer (EDX), the presence or absence of a specific element in the binder resin 136 can be grasped.

  The thickness of the light wavelength conversion layer 131 is preferably 10 μm or more and 200 μm or less. When the film thickness of the light wavelength conversion layer 131 is within this range, it is suitable for reducing the weight and thinning the backlight device. Regarding the film thickness of the light wavelength conversion layer 131, the cross section of the light wavelength conversion sheet is photographed using a scanning electron microscope (SEM), and the thickness of the light wavelength conversion layer in the image of the cross section is photographed. Is measured at 20 points and the average value of the thicknesses at the 20 points is taken. The upper limit of the film thickness of the light wavelength conversion layer 131 is more preferably less than 170 μm.

<< binder resin >>
The binder resin 136 includes a cured product (polymerized product, crosslinked product) of a curable binder resin precursor. The curable binder resin precursor includes one or more compounds selected from the group consisting of sulfur compounds, phosphorus compounds, and nitrogen compounds (hereinafter, this compound will be referred to as “specific compound”) and a polymerizable compound. It is preferable to include.

<Sulfur compound>
The sulfur compound is a compound containing sulfur. The sulfur compound is not particularly limited, but examples thereof include a thiol compound, a thioether compound, a disulfide compound and a thiophene compound. When a thiol compound is used as the sulfur compound, in the binder resin 136, the thiol compound and the polymerizable compound preferably form a copolymer by a thiol-ene reaction. By copolymerizing the thiol and the polymerizable compound, the thiol compound can be fixed in the binder resin. In this embodiment, the thiol compound and the polymerizable compound are separate compounds, but a thiol compound having a thiol group and a radically polymerizable functional group in one molecule may be used. When a thiol compound is used, it is particularly preferable to use a secondary thiol compound or a tertiary thiol compound from the viewpoint of pot life during coating and suppression of odor.

  The secondary thiol compound means a compound in which two hydrocarbon groups are bonded to the carbon to which the thiol group is bonded. The tertiary thiol compound means a compound in which three hydrocarbon groups are bonded to carbon to which a thiol group is bonded. In the secondary thiol compound and the tertiary thiol compound, the number of thiol groups is 1 or more in one molecule, but it is preferably 2 or more from the viewpoint of improving the durability of the quantum dots.

式中、Ｒ^１は置換されていてもよい炭素原子数１〜１０のアルキル基であり、Ｒ^２は置換されていてもよい炭素原子数１〜１０のアルキレン基であり、Ｒ^３は炭素原子以外の原子を含んでいてもよい炭素原子数１〜１５のｎ価の脂肪族基であり、ｍは１〜２０の整数であり、ｎは１〜３０の整数である。 The secondary thiol compound or the tertiary thiol compound is not particularly limited, but from the viewpoint of curability during formation of the light wavelength conversion layer and improvement of quantum dot durability, a compound represented by the following general formula (1) is used. preferable.

In the formula, R ¹ is an optionally substituted alkyl group having 1 to 10 carbon atoms, R ² is an optionally substituted alkylene group having 1 to 10 carbon atoms, and R ³ is a carbon atom. Is an n-valent aliphatic group having 1 to 15 carbon atoms which may contain atoms other than, m is an integer of 1 to 20, and n is an integer of 1 to 30.

The alkyl group of R ¹ may be linear or branched. Examples of the alkyl group for R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, tert-pentyl group, isopentyl group, 2-methylbutyl group, 1-ethylpropyl group, hexyl group, isohexyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3 , 3-dimethylbutyl group, 2,2-dimethylbutyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl Group, 2-ethylbutyl group, heptyl group, octyl group, nonyl group, decyl group and the like.

The alkylene group for R ² may be linear or branched. Examples of the alkylene group for R ² include a methylene group, an ethylene group, a trimethylene group, a propylene group, and an isopropylidene group.

When the alkyl group of R ¹ or the alkylene group of R ² is substituted, the substituent may be a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, a carboxyl group, a phenyl group or the like. Included are selected groups. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

One methylene group or two or more non-adjacent methylene groups in the alkyl group of R ¹ or the alkylene group of R ² is —O—, —S—, —SO ₂ —, —CO—, —COO—, — ^{OCO -, - NR 4 -,} - CONR 4 -, - NR 4 CO -, - N = CH- and -CH = CH- may be substituted with at least one group selected from the group consisting of (formula In the formula, R ^4's each independently represent hydrogen or an alkyl group having 1 to 5 carbon atoms.)

Examples of the atom other than the carbon atom that may be contained in the aliphatic group of R ³ include a nitrogen atom, an oxygen atom, and a sulfur atom.

Among these, R ¹ is an optionally substituted alkyl group having 1 to 5 carbon atoms and R ² is R ² from the viewpoint of improving the curability during formation of the light wavelength conversion layer and the durability of the quantum dots. It is an optionally substituted alkylene group having 1 to 5 carbon atoms, R ³ is an aliphatic group having 1 to 10 carbon atoms, m is 1 to 10 and n is 1 to 2 Higher grade thiol compounds are preferred. One methylene group or two or more non-adjacent methylene groups in the alkylene group for R ² here may be substituted with the same groups as described above.

  Specific examples of the secondary thiol compound include 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2. , 4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), trimethylolpropane tris (3-mercaptobutyrate), trimethylolethanetris (3-mercaptobutyrate), etc. Can be mentioned. Specific examples of the tertiary thiol compound include tert-butyl mercaptan.

式中、ｑは０または１の整数であり、Ｒ^５〜Ｒ^７は、それぞれ独立して、水素、水酸基、置換されていてもよい炭素原子数１〜３０の直鎖または分岐のアルキル基、置換されていてもよい炭素数１〜３０の直鎖または分岐のアルコキシ基、置換されていてもよい炭素数１〜３０の直鎖または分岐のアルケニル基、置換されていてもよい炭素数１〜３０の直鎖または分岐のアルキニル基、置換されていてもよい炭素数３〜６のシクロアルキル基、置換されていてもよいフェニル基、置換されていてもよいビフェニル基、置換されていてもよいナフチル基、置換されていてもよいフェノキシ基、または置換されていてもよい複素環基、または水酸基を表す。 <Phosphorus compound>
A phosphorus compound is a compound containing phosphorus. The phosphorus compound is not particularly limited, and examples thereof include phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. Among these, the compound represented by the following general formula (2) is preferable from the viewpoint of curability during formation of the light wavelength conversion layer and improvement of quantum dot durability.

In the formula, q is an integer of 0 or 1, and R ^{5 to} R ⁷ are each independently hydrogen, a hydroxyl group, an optionally substituted linear or branched alkyl group having 1 to 30 carbon atoms, C1-C30 linear or branched alkoxy group which may be substituted, C1-C30 linear or branched alkenyl group which may be substituted, C1-C1 which may be substituted. 30 linear or branched alkynyl group, optionally substituted cycloalkyl group having 3 to 6 carbon atoms, optionally substituted phenyl group, optionally substituted biphenyl group, optionally substituted. It represents a naphthyl group, an optionally substituted phenoxy group, an optionally substituted heterocyclic group, or a hydroxyl group.

When any of R ^{5 to} R ⁷ has a substituent, the substituent is a halogen atom (F, Cl, Br), an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms. An alkenyl group having 1 to 6 carbon atoms, an alkynyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a (meth) acryloyl group, a (meth) acryloyloxy group, an amino group, a hydroxyl group, a carboxyl group, Examples thereof include an alkylamino group having 1 to 6 carbon atoms, a nitro group, a phenyl group, a biphenyl group, a naphthyl group, a phenoxy group, or a heterocyclic group.

  The heterocyclic group, pyridyl group, pyrimidinyl group, pyridazyl group, pyrazyl group, furyl group, thienyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, triazolyl group, pyrrole group, pyrazolyl group Or a tetrazolyl group.

  Specific examples of the phosphorus compound include tris (2-ethylhexyl) phosphite, trilaurylphosphite, tris (tridecyl) phosphite, bis (decyl) pentaerythritol diphosphite, and bis (tridecyl) pentaerythritol diphosphite. , Triphenyl phosphite, trisnonyl phenyl phosphite, butyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, dibutyl phosphate, dimethyl vinyl phosphate, di-2-ethylhexyl hydrogen phosphite , Dioleyl hydrogen phosphite and the like.

<Nitrogen compound>
A nitrogen compound is a compound containing nitrogen. The nitrogen compound is not particularly limited, but an amine compound is preferable from the viewpoint of curability during formation of the light wavelength conversion layer and improvement of the quantum dot durability. The amine compound may be a primary amine compound, a secondary amine compound, a tertiary amine compound, or a diamine compound.

  Specific examples of the amine compound include laurylamine, myristylamine, cetylamine, stearylamine, oleylamine, behenylamine, distearylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylstearylamine, dilaurylmonomethylamine, trioctylamine. , Oleyl propylene diamine and the like.

<Polymerizable compound>
Since the polymerizable compound is the same as the polymerizable compound described in the first embodiment, the description is omitted except for the following.

  Among the photopolymerizable compounds, a photopolymerizable compound having at least one of a hydroxyl group and a carboxyl group is preferable from the viewpoint of further improving durability. At least one hydroxyl group or carboxyl group may be present in one molecule.

  Examples of the photopolymerizable compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate. Hydroxyalkyl (meth) acrylates such as 4-hydroxybutyl (meth) acrylate and cyclohexanedimethanol mono (meth) acrylate; glycerol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate and Polyalkylene glycol mono (meth) acrylate such as mono (meth) acrylate compound of polyethylene glycol-polypropylene glycol copolymer, hydroxyethyl ( Data) acrylamide, allyl alcohol, pentaerythritol tri (meth) acrylate.

  As the photopolymerizable compound having a carboxyl group, unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, cinnamic acid and maleic anhydride; itaconic acid monoethyl ester , Monoalkyl esters of unsaturated dicarboxylic acids such as fumaric acid monobutyl ester and maleic acid monobutyl ester; ω-carboxypolycaprolactone (meth) acrylate, (meth) acrylic acid dimer, 2- (meth) acryloyloxyethyl phthalate Examples thereof include acid and carboxyl group-containing (meth) acrylates such as 2- (meth) acryloyloxyethylhexahydrophthalic acid.

<< Quantum dots >>
Since the quantum dot 137 is similar to the quantum dot 15, the description is omitted except for the following. The quantum dots of this embodiment may be wrapped with barrier particles, but may not be wrapped with barrier particles. The quantum dots 137 shown in FIG. 13 are not wrapped with barrier particles. The quantum dot 137, like the quantum dot 15, includes a first quantum dot 137A and a second quantum dot 137B having an emission band in a wavelength range different from that of the first quantum dot 137A.

<Light scattering particles>
The light-scattering particles 134 are similar to the light-scattering particles 18, and thus the description thereof is omitted here.

<< Light-transmissive substrate >>
The thickness of the light transmissive substrates 132 and 133 is not particularly limited, but is preferably 10 μm or more and 500 μm or less. If the thickness of the light transmissive base materials 132 and 133 is less than 10 μm, wrinkles and folds may occur during the assembly and handling of the light wavelength conversion sheet, and if it exceeds 150 μm, the weight of the display is reduced and the thin film is formed. May not be suitable for The more preferable lower limit of the thickness of the light transmissive substrates 132 and 133 is 50 μm or more, and the more preferable upper limit thereof is 400 μm or less.

  The average thickness of the light transmissive substrates 132 and 133 can be calculated using, for example, an image of a cross section taken by a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). .

  Examples of the constituent materials of the light transmissive base materials 132 and 133 include the same materials as those of the light transmissive base material 21. The light transmissive base materials 132 and 133 may be composed of a single base material, or may be a laminated base material composed of a plurality of base materials. Such a laminated base material may be composed of a plurality of layers composed of layers of the same kind of constituent material, or may be composed of a plurality of layers composed of layers of different kinds of constituent materials, depending on the application. Good.

<<< light diffusion layer >>>
The light diffusion layers 134 and 135 have unevenness on the surface, and the unevenness can diffuse the light entering and exiting the light wavelength conversion sheet 130. By providing the light diffusion layers 14 and 15, the light wavelength conversion efficiency of the light wavelength conversion sheet 130 can be further increased. The light diffusion layers 134 and 135 contain surface irregularity forming particles and a binder resin.

<< Surface irregularity forming particles >>
The surface irregularity forming particles are mainly for forming irregularities on the surface of the light diffusion layer. However, the surface irregularity-forming particles themselves may exhibit light scattering performance.

  The average particle size of the particles for forming surface irregularities is preferably 10 times or more and 20,000 times or less, and more preferably 10 to 5000 times the average particle size of the quantum dots 137 described above. When the average particle size of the surface irregularity forming particles is less than 10 times the average particle size of the quantum dots, sufficient light diffusibility may not be obtained in the light diffusing layer, and the average particle size of the surface irregularity forming particles is When the average particle diameter of the quantum dots exceeds 20,000 times, the light diffusion performance of the light diffusion layer is excellent, but the light transmittance of the light diffusion layer is likely to be significantly reduced. The average particle size of the surface irregularity forming particles can be measured by the same method as the above-mentioned average particle size of the quantum dots.

  Specifically, the average particle diameter of the surface irregularity forming particles is, for example, preferably 1 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less. If the average particle size of the surface irregularity forming particles is less than 1 μm, the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient, and in order to obtain sufficient light diffusivity, the amount of the surface irregularity forming particles added Need to be a lot. On the other hand, when the average particle size of the surface irregularity forming particles exceeds 30 μm, the light diffusion performance is excellent, but the light transmittance of the light diffusion layer is likely to be significantly reduced.

  The absolute value of the difference in refractive index between the particles for forming surface irregularities and the binder resin is preferably 0.02 or more and 0.15 or less. If it is less than 0.02, the optical diffusivity due to the refractive index of the particles for forming surface irregularities cannot be obtained optically, and the improvement of the light wavelength conversion efficiency of the light wavelength conversion sheet may be insufficient, and When it exceeds 15, the transmittance of the light diffusion layer may be lowered. A more preferable lower limit of the difference in refractive index between the surface unevenness forming particles and the binder resin is 0.03 or more, and a more preferable upper limit thereof is 0.12 or less. Either of the refractive index of the surface irregularity forming particles and the refractive index of the binder resin may be higher. The refractive indices of the surface unevenness forming particles and the binder resin can be measured by the same method as the refractive indexes of the light scattering particles 18 and the first binder resin.

  The shape of the surface irregularity-forming particles is not particularly limited, and examples thereof include spherical shapes (true spheres, substantially true spheres, elliptical spheres, etc.), polyhedron shapes, rod shapes (cylindrical shapes, prismatic shapes, etc.), flat plate shapes, scaly shapes, irregular shapes Etc. The particle diameter of the surface irregularity-forming particles can be a value of a true sphere having the same volume when the shape of the surface irregularity-forming particles is not spherical.

  The surface irregularity-forming particles are preferably chemically bonded to the binder resin from the viewpoint of firmly fixing the surface irregularity-forming particles in the binder resin. This chemical bond can be realized by using surface irregularity forming particles whose surface is modified with a silane coupling agent. The silane coupling agent is the same as the silane coupling agent described in the section of the light-scattering particles, so the description will be omitted here.

  The surface unevenness forming particles may be particles made of an organic material or particles made of an inorganic material. The organic material forming the surface irregularity forming particles is not particularly limited, and examples thereof include polyester, polystyrene, melamine resin, (meth) acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzoguanamine resin, benzoguanamine / formaldehyde condensation resin. , Polycarbonate, polyethylene, polyolefin and the like. Among them, a crosslinked acrylic resin is preferably used. The inorganic material forming the light diffusing particles is not particularly limited, and examples thereof include silica, alumina, titania, tin oxide, antimony-doped tin oxide (ATO), and inorganic oxides such as zinc oxide fine particles. Among them, silica and / or alumina are preferably used.

<< binder resin >>
The binder resin is not particularly limited, but since the cured product (polymerized product or crosslinked product) of the polymerizable compound described in the section of the binder resin 12 can be used, the description thereof is omitted here.

<<<< Other light wavelength conversion sheets >>>>
The light wavelength conversion sheet according to the present embodiment is a light wavelength conversion sheet in which the light wavelength conversion layer 11 of the light wavelength conversion sheets 10, 20, 40, and 50 according to the first embodiment is replaced with the light wavelength conversion layer 131. May be. In the light wavelength conversion sheet 40, the light wavelength conversion layer 11 and the light control sheet 41 are bonded together via the adhesive layer 42. However, the light wavelength conversion layer composition is directly applied to the light control sheet and cured. By doing so, the light wavelength conversion layer 131 and the light control sheet may be directly bonded. Further, it may be a light wavelength conversion sheet having a lens portion like the light wavelength conversion layer 31 of the light wavelength conversion sheet 30. In this case, in these light wavelength conversion sheets, the water vapor transmission rate at 40 ° C. and 90% relative humidity is 0.1 g / (m ² · 24 h) or more and / or 23 ° C. and 90% relative humidity in the entire sheet. The oxygen transmission rate may be 0.1 cm ³ / (m ² · 24h · atm) or more. In addition, in these light wavelength conversion sheets, the water vapor transmission rate at 40 ° C. and relative humidity of 90% may be 1 g / (m ² · 24 h) or more. The oxygen transmission rate at a humidity of 90% may be 1 cm ³ / (m ² · 24h · atm) or more. Further, also in these light wavelength conversion sheets, wavelength conversion is performed by quantum dots on one entire surface of the light wavelength conversion sheet before and after the durability test in which the light wavelength conversion sheet is left in an environment of 60 ° C. and relative humidity of 90% for 500 hours. When the brightness of the light emitted from the center portion of the other surface of the light wavelength conversion sheet is measured by irradiating a predetermined amount of light that is from the center portion of the other surface of the light wavelength conversion sheet before the durability test. The rate of change in the brightness of the light emitted from the central portion of the other surface of the light wavelength conversion sheet after the durability test with respect to the brightness of the emitted light is preferably within ± 10%, and within ± 5%. Is more preferable. Further, also in these light wavelength conversion sheets, when a durability test of leaving for 500 hours in an environment of 60 ° C. and a relative humidity of 90%, the deterioration width of the peripheral portion of the light wavelength conversion sheet after the durability test is It is preferably 5 mm or less, more preferably 3 mm or less.

<<< Method of manufacturing light wavelength conversion sheet >>>
The light wavelength conversion sheet 130 can be manufactured, for example, as follows. First, although not shown, the composition for the light diffusion layer containing the surface irregularity forming particles and the curable binder resin precursor is applied to one surface of the light transmissive substrate 132 and dried to form the composition for the light diffusion layer. Form a coating film of an object. Similarly, a coating film of the composition for the light diffusion layer is formed on one surface of the light transmissive base material 133.

  Next, the coating film of the composition for the light diffusion layer is cured by irradiation with ionizing radiation. Thus, as shown in FIG. 14A, the light diffusion layer 134 is formed on one surface of the light transmissive base material 132, and the light transmissive base material 132 with the light diffusion layer 134 is formed. Although not shown, the light-transmissive base material 133 with the light diffusion layer 135 is similarly formed.

  After forming the light transmissive base material 133 with the light diffusion layer 135, as shown in FIG. 14B, the side opposite to the surface on the light diffusion layer 135 side in the light transmissive base material 133 with the light diffusion layer 135. To the surface, the quantum dot 137, a curable binder resin precursor containing the above-mentioned specific compound and a polymerizable compound, and a composition for a light wavelength conversion layer containing a light scattering particle 138 are applied, dried, and a light wavelength is applied. A coating film 139 of the conversion layer composition is formed.

  The content of the quantum dots based on the total solid content of the composition for a light wavelength conversion layer is preferably 0.01% by mass or more and 2% by mass or less, and 0.03% by mass or more and 1% by mass or less. More preferable. When the content of the quantum dots is less than 0.01% by mass, sufficient emission intensity may not be obtained, and when the content of the quantum dots exceeds 2% by mass, sufficient transmitted light of excitation light is obtained. The strength may not be obtained.

  The content of the specific compound is 5% by mass or more based on the total mass of the solid content of the composition for a light wavelength conversion layer. If the content of the specific compound is less than 5% by mass, deterioration of the quantum dots may not be suppressed. The lower limit of the content of the specific compound is more preferably 10% by mass or more, and the upper limit of the content of the specific compound is 70% by mass or less based on the total solid content of the composition for a light wavelength conversion layer. Is preferable, and more preferably 50% by mass or less. When the content of the specific compound with respect to the total solid content of the composition for the light wavelength conversion layer exceeds 70% by mass, sufficient curability may not be obtained during formation of the light wavelength conversion layer. In addition, when the composition for light wavelength conversion layers contains two or more specific compounds, the said content shall mean the total content of a specific compound.

  The content of the polymerizable compound relative to the total solid content of the composition for light wavelength conversion layer is preferably 30% by mass or more and 95% by mass or less, and more preferably 50% by mass or more and 90% by mass or less. When the content of the polymerizable compound is less than 30% by mass, sufficient curability may not be obtained when forming the light wavelength conversion layer, and the content of the polymerizable compound exceeds 95% by mass. If so, the effect of improving durability by the above-mentioned specific compound may not be sufficiently obtained. When the composition for light wavelength conversion layer contains both a photopolymerizable compound and a thermopolymerizable compound, the above content means the total content of the photopolymerizable compound and the thermopolymerizable compound. To do.

  The content of the light scattering particles 18 with respect to the total solid content of the composition for the light wavelength conversion layer is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 30% by mass or less. preferable. When the content of the light scattering particles is less than 1% by mass, the light scattering effect may not be sufficiently obtained, and when the content of the light scattering particles exceeds 50% by mass, Mie scattering occurs. Since it becomes difficult, the light-scattering effect may not be sufficiently obtained, and further, the workability may be deteriorated because there are too many light-scattering particles.

  The composition for light wavelength conversion layer preferably contains a polymerization initiator. Since the polymerization initiator is the same as that in the first embodiment, its explanation is omitted here.

  After forming the coating film 139 of the composition for a light wavelength conversion layer, as shown in FIG. 15 (A), the surface of the light transmissive substrate 132 with the light diffusion layer 14 opposite to the surface on the light diffusion layer 134 side is The light transmissive substrate 132 with the light diffusion layer 134 is arranged on the coating film 139 of the composition for light wavelength conversion layer so as to come into contact with the coating film 139 of the composition for light wavelength conversion layer. Thereby, the coating film 139 of the composition for the light wavelength conversion layer is sandwiched between the light transmissive base materials 132 and 133.

  Next, as shown in FIG. 15B, the coating film 139 of the composition for a light wavelength conversion layer is irradiated with ionizing radiation or heat is applied to the curable binder resin through the light transmissive base material 132. The precursor is cured to form the light wavelength conversion layer 131, and the light wavelength conversion layer 131 and the light transmission base material 132 with the light diffusion layer 134 and the light transmission base material 133 with the light diffusion layer 145 are integrated. Turn into As a result, the light wavelength conversion sheet 130 shown in FIG. 13 is obtained.

According to the present embodiment, as in the first embodiment, the light wavelength conversion sheet 130 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or light. Since the oxygen conversion rate at 23 ° C. and 90% relative humidity in the wavelength conversion sheet 130 is 0.1 cm ³ / (m ² · 24 h · atm) or more, a barrier film composed of a light-transmissive base material and a barrier layer. Not equipped. Therefore, pinholes and cracks due to the barrier film do not occur, and thus dot-like luminance defects can be suppressed. Further, since the light wavelength conversion layer 131 has the function of suppressing the deterioration of the quantum dots 137, the deterioration of the quantum dots 137 can be suppressed even without the barrier film. Further, since the light wavelength conversion sheet 130 does not include the barrier film, it is possible to reduce the thickness and the manufacturing cost.

  It is thought that the cause of the deterioration of the quantum dots is that the ligands coordinated to the surface of the quantum dots made of thiol, phosphine, etc. are desorbed from the quantum dots by light or heat, and the quantum dots are easily oxidized. . According to the present embodiment, the content of the specific element in the light wavelength conversion layer 131 measured by X-ray fluorescence analysis is 0.5% by mass or more, and therefore deterioration of the quantum dots 137 is suppressed. it can. This is because even if the ligand is desorbed from the quantum dot 137, the sulfur component, phosphorus component, or nitrogen component contained in the binder resin 136 and existing around the quantum dot 137 assists the role of the ligand. It is considered that such a function (for example, a function of binding to the quantum dot 137 instead of the ligand to substitute for the ligand) is exerted. Thereby, the durability can be improved, and the deterioration of the quantum dots 137 existing in the peripheral portion 130C (see FIG. 13) can be suppressed. Further, by setting the content of the specific element in the light wavelength conversion layer 131 measured by fluorescent X-ray analysis to 0.5% by mass or more, the light wavelength conversion layer 131 has a deterioration suppressing function of the quantum dots 137. Can be granted.

Further, according to the present embodiment, the content of the sulfur element in the light wavelength conversion layer 131 measured by fluorescent X-ray analysis is set to 0.5 mass% or more to suppress the deterioration of the quantum dots 137. The light wavelength conversion sheet 130 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and a relative humidity of 90% and / or oxygen permeation of the light wavelength conversion sheet 130 at a temperature of 23 ° C. and a relative humidity of 90%. Even if the rate is 0.1 cm ³ / (m ² · 24h · atm) or more, it is not necessary to separately provide a barrier film. This makes it easier to improve the quality by simplifying the process of the light wavelength conversion sheet, and it is possible to reduce the thickness of the light wavelength conversion sheet and reduce the manufacturing cost.

  Moreover, since the composition for light wavelength conversion layer contains 5 mass% or more of the above-mentioned specific compound with respect to the total solid content of the composition for light wavelength conversion layer, deterioration of quantum dots can be suppressed. As a result, by using the composition for a light wavelength conversion layer of the present embodiment, the light wavelength conversion layer 131 which can improve the durability and can suppress the deterioration of the quantum dots 137 existing in the peripheral portion 130C is formed. be able to.

According to the present embodiment, the light wavelength conversion sheet 130 has a water vapor transmission rate of 0.1 g / (m ² · 24 h) or more at 40 ° C. and 90% relative humidity and / or oxygen at 23 ° C. and 90% relative humidity. Even before or after the durability test in which the light wavelength conversion sheet 130 is left in an environment of 60 ° C. and 90% relative humidity for 500 hours even if the transmittance is 0.1 cm ³ / (m ² · 24 h · atm) or more. The rate of change in the luminance of the light emitted from the central portion of the surface of the light wavelength conversion sheet 130 after the durability test is ± 10 with respect to the luminance of the light emitted from the central portion of the surface of the light wavelength conversion sheet 130 before the durability test. When it is within%, the deterioration of the central portion of the light wavelength conversion sheet 130 can be suppressed. Further, in this case, the deterioration width of the peripheral portion of the light wavelength conversion sheet 130 after the durability test, which is left in an environment of 60 ° C. and relative humidity of 90% for 500 hours, can be set to 5 mm or less. Accordingly, it is possible to suppress the deterioration of the central portion and the peripheral portion of the light wavelength conversion sheet 130 without providing the barrier film.

  The light wavelength conversion sheet according to the present embodiment can also be incorporated into a backlight device or an image display device having the same structure as the backlight devices 70 and 120 or the image display device 60 described in the first embodiment.

  In order to explain the present invention in detail, examples will be given below, but the present invention is not limited to these descriptions.

<Production of light wavelength conversion particles>
First, light wavelength conversion particles were obtained by the procedure shown below.
(Light wavelength conversion particle 1)
First, 0.2 parts by mass of green light emitting quantum dots (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 3.3 nm) and 0.2 parts by mass. A red light emitting quantum dot (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 5.2 nm) was prepared. After preparing the green light emitting quantum dot and the red light emitting quantum dot, the surfaces of the green light emitting quantum dot and the red light emitting quantum dot are covered with dodecylamine, and these quantum dots are dissolved in a toluene solution (0.4 mL, 1.5 μM / L). Dispersed. Next, tetraethoxysilane (TEOS, 10 μL) was added to this solution and stirred for 3 hours to prepare an organic solution 1.

  On the other hand, 3-mercaptopropyltrimethoxysilane (MPS, 1 μL) was mixed with ethanol (25 mL) and aqueous ammonia (4 mL, ammonia concentration 10 wt%) to prepare an aqueous solution 2.

  Then, when the organic solution 1 and the aqueous solution 2 were mixed and stirred for 3 hours, the green light emitting quantum dots and the red light emitting quantum dots moved to the water phase, and in the water phase, an assembly of the green light emitting quantum dots and the red light emitting quantum dots. Was formed. The aggregate was removed by centrifugation.

  Finally, 0.5 mL of an aqueous solution in which the above aggregate was dispersed was taken out, ethanol (8 mL) and ammonia water (0.1 mL, 25 wt%) were added, and TEOS (14 μL) was further added. As a result, the aggregate consisting of the green light emitting quantum dots and the red light emitting quantum dots was wrapped with silica glass to obtain light wavelength conversion particles 1 having an average particle diameter of 50 nm.

(Light wavelength conversion particle 2)
First, 0.2 parts by mass of green light emitting quantum dots (product name “CdSe / ZnS 530”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 3.3 nm) are prepared. After preparing the green light emitting quantum dots, the surface of the green light emitting quantum dots was covered with dodecylamine, and the green light emitting quantum dots were dispersed in a toluene solution (0.4 mL, 1.5 μM / L). Next, tetraethoxysilane (TEOS, 10 μL) was added to this solution, and the mixture was stirred for 3 hours to obtain organic solution 3.

  Then, when the organic solution 3 and the aqueous solution 2 prepared in Example 1 were mixed and stirred for 3 hours, the green light emitting quantum dots moved to the water phase, and further an aggregate of green light emitting quantum dots was formed in the water phase. . The aggregate was removed by centrifugation.

  Finally, 0.5 mL of an aqueous solution in which the above aggregate was dispersed was taken out, ethanol (8 mL) and ammonia water (0.1 mL, 25 wt%) were added, and TEOS (14 μL) was further added. As a result, the aggregate of green light emitting quantum dots was wrapped with silica glass to obtain light wavelength conversion particles 2 containing green light emitting quantum dots and having an average particle diameter of 50 nm.

(Light wavelength conversion particle 3)
First, 0.2 parts by mass of red light emitting quantum dots (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 5.2 nm) are prepared. After preparing the red light emitting quantum dots, the surface of the red light emitting quantum dots was covered with dodecylamine, and the red light emitting quantum dots were dispersed in a toluene solution (0.4 mL, 1.5 μM / L). Next, tetraethoxysilane (TEOS, 10 μL) was added to this solution and stirred for 3 hours to obtain organic solution 4.

  Then, when the organic solution 4 and the aqueous solution 2 prepared in Example 1 were mixed and stirred for 3 hours, the red light emitting quantum dots moved to the water phase, and an aggregate of the red light emitting quantum dots was formed in the water phase. . The aggregate was removed by centrifugation.

  Finally, 0.5 mL of an aqueous solution in which the above aggregate was dispersed was taken out, ethanol (8 mL) and ammonia water (0.1 mL, 25 wt%) were added, and TEOS (14 μL) was further added. As a result, an aggregate of red light emitting quantum dots was wrapped with silica glass to obtain light wavelength conversion particles 3 containing red light emitting quantum dots and having an average particle diameter of 50 nm.

<Preparation of composition for light wavelength conversion sheet>
First, each component was mixed so as to have the composition shown below to obtain a composition for a light wavelength conversion layer.
(Composition 1 for light wavelength conversion layer)
-Epoxy acrylate (Product name "Unidick V-5500", manufactured by DIC): 99 parts by mass-Light wavelength conversion particles 1: 5 parts by mass-Alumina particles (light scattering particles, product name "DAM-03", electricity Chemical Industry Co., Ltd., average particle diameter 4 μm): 10 parts by mass Photoinitiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) 184”, manufactured by BASF Japan Ltd.): 1 part by mass

(Composition 2 for light wavelength conversion layer)
-Epoxy acrylate (Product name "Unidick V-5500", manufactured by DIC): 99 parts by mass-Light wavelength conversion particles 2: 2.5 parts by mass-Light wavelength conversion particles 3: 2.5 parts by mass-Alumina particles ( Light-scattering particles, product name “DAM-03”, manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 4 μm: 10 parts by mass Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) 184” , Manufactured by BASF Japan): 1 part by mass

(Composition 3 for light wavelength conversion layer)
Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 89 parts by mass Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS , Average particle diameter 3.3 nm): 0.20 parts by mass red light emitting quantum dots (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 5.2 nm). : 0.20 parts by mass Alumina particles (light scattering particles, product name "DAM-03", manufactured by Denki Kagaku Kogyo, average particle size 4 μm): 10 parts by mass Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone) , Product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 1 part by mass

(Composition 4 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 90 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 10 parts by mass -Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass-red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 5.2 nm: 0.20 parts by mass radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name " Irgacure (registered trademark) 184 ", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 5 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 90 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 10 parts by mass -Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass-red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm: 0.20 parts by mass-alumina particles (light scattering particles, product name "DAM-03") Manufactured by Denki Kagaku Kogyo Co., Ltd., average particle diameter 4 μm): 10 parts by mass radical polymerization initiator (1-hydroxycyclohexylphenylketo) Product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 6 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 90 parts by mass 2-methacryloyloxyethyl acid phosphate (product name "light ester P-2M", manufactured by Kyoeisha Chemical Co., Ltd.): 10 parts by mass Parts / green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass / red light emitting quantum dots (product Name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm: 0.20 parts by mass Alumina particles (light scattering particles, product name "DAM-03" , Manufactured by Denki Kagaku Kogyo Co., Ltd., average particle diameter 4 μm): 10 parts by mass radical polymerization initiator (1-hydroxycyclohexylpheny Luketone, product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 7 for light wavelength conversion layer)
Epoxy acrylate (Product name "Unidick V-5500", manufactured by DIC): 90 parts by mass Stearylamine (Product name "Pharmine 80", manufactured by Kao): 10 parts by mass Green emission quantum dots (Product name " CdSe / ZnS 530 ", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm: 0.20 parts by mass-red light emitting quantum dots (product name" CdSe / ZnS 610 ", SIGMA-. ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm: 0.20 parts by mass Alumina particles (light scattering particles, product name "DAM-03", manufactured by Denki Kagaku Kogyo Co., Ltd., average particle) Diameter 4 μm): 10 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name “Irgacure (registered trademark) ) 184 ”, manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 8 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 90 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 5 parts by mass -2-metachloroyloxyethyl acid phosphate (product name "light ester P-2M", manufactured by Kyoeisha Chemical Co., Ltd.): 5 parts by mass. Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, Core: CdSe, Shell: ZnS, average particle size 3.3 nm: 0.20 parts by mass Red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, Average particle size 5.2 nm: 0.20 parts by mass Alumina particles (light scattering particles, product name "DAM-03", Gas Chemical Industries, Ltd., average particle size 4 [mu] m): 10 parts by mass polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184" manufactured by BASF Japan Ltd.): 0.2 parts by weight

(Composition 9 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 75 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 25 parts by mass -Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass-red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm: 0.20 parts by mass-alumina particles (light scattering particles, product name "DAM-03") Manufactured by Denki Kagaku Kogyo Co., Ltd., average particle diameter 4 μm): 10 parts by mass radical polymerization initiator (1-hydroxycyclohexylphenylketo) Product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 10 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 50 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 50 parts by mass -Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass-red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm: 0.20 parts by mass-alumina particles (light scattering particles, product name "DAM-03") Manufactured by Denki Kagaku Kogyo Co., Ltd., average particle diameter 4 μm): 10 parts by mass radical polymerization initiator (1-hydroxycyclohexylphenylketo) Product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 11 for light wavelength conversion layer)
-Epoxy acrylate (Product name "Unidick V-5500", manufactured by DIC): 100 parts by mass Green light emitting quantum dots (Product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, Core: CdSe, Shell: ZnS , Average particle size 3.3 nm): 0.20 parts by mass red light emitting quantum dots (product name “CdSe / ZnS 610”, manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 5.2 nm). : 0.20 parts by mass Radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.): 0.2 parts by mass

(Composition 12 for light wavelength conversion layer)
-Epoxy acrylate (product name "Unidick V-5500", manufactured by DIC): 97 parts by mass-Trimethylolpropane tris (3-mercaptobutyrate) (product name "TPMB", manufactured by Showa Denko KK): 3 parts by mass -Green light emitting quantum dots (product name "CdSe / ZnS 530", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle size 3.3 nm): 0.20 parts by mass-red light emitting quantum dots (product name "CdSe / ZnS 610", manufactured by SIGMA-ALDRICH, core: CdSe, shell: ZnS, average particle diameter 5.2 nm: 0.20 parts by mass radical polymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name " Irgacure (registered trademark) 184 ", manufactured by BASF Japan Ltd.): 0.2 parts by mass

<Preparation of composition for overcoat layer>
Each component was mixed so as to have the composition shown below to obtain a composition for an overcoat layer.
(Composition 1 for overcoat layer)
-Zinc acrylate (product name "ZN-DA" manufactured by Nippon Shokubai Co., Ltd.): 30 parts by mass-Methanol: 70 parts by mass-Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184," (Manufactured by BASF Japan): 1 part by mass

(Composition 2 for overcoat layer)
-A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (product name "Aronix (registered trademark) M-403", manufactured by Toagosei Co., Ltd.): 30 parts by mass, methanol: 70 parts by mass, photopolymerization initiator (1 -Hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184, manufactured by BASF Japan Ltd.): 1 part by mass

<Preparation of composition for light diffusion layer>
The components were blended so as to have the composition shown below to obtain a light diffusion layer composition 1.
(Composition 1 for light diffusion layer)
-Pentaerythritol triacrylate: 99 parts by mass-Surface irregularity forming particles (crosslinked polystyrene resin beads, product name "SBX-4", manufactured by Sekisui Plastics Co., Ltd., average particle diameter 4 µm): 158 parts by mass-Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184, manufactured by BASF Japan Ltd.): 1 part by mass-solvent (methyl isobutyl ketone: cyclohexanone = 1: 1 (mass ratio)): 170 parts by mass

<Example 1>
First, the composition 1 for a light wavelength conversion layer was applied to one surface of a polyethylene terephthalate (PET) base material (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) having a thickness of 50 μm to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain a light wavelength conversion layer. Finally, the PET substrate was peeled off to form a light wavelength conversion sheet according to Example 1 having only a light wavelength conversion layer with a thickness of 100 μm. The thickness of the light wavelength conversion sheet was measured by photographing the cross section of the light wavelength conversion sheet with a scanning electron microscope (SEM) and measuring the thickness of the light wavelength conversion sheet at 20 points in the image of the cross section. The average value of the thickness of the spots was used.

<Example 2>
In Example 2, a light wavelength conversion sheet was produced in the same manner as in Example 1 except that the composition 2 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 3>
In Example 3, a light wavelength conversion sheet was produced in the same manner as in Example 1 except that the PET substrate was not peeled off from the light wavelength conversion layer. The light wavelength conversion sheet according to Example 3 was composed of a light wavelength conversion sheet and a PET base material. The thickness of the light wavelength conversion sheet according to Example 3 was 140 μm.

<Example 4>
In Example 4, a light wavelength conversion sheet was produced in the same manner as in Example 2 except that the PET substrate was not peeled off from the light wavelength conversion layer. The light wavelength conversion sheet according to Example 4 was composed of a light wavelength conversion sheet and a PET base material.

<Example 5>
The composition 1 for light wavelength conversion layer is coated and filled in a molding die having a concave portion having an inverse shape to the desired shape of a unit prism, and then a polyethylene terephthalate (PET) substrate (product name "Lumirror T60" (manufactured by Toray Industries, Inc.) was supplied at a running speed of 10 m / min, and pressed against the molding die from above the composition 1 for light wavelength conversion layer on the die surface. Then, in the pressed state, the composition 1 for light wavelength conversion layer was irradiated with ultraviolet rays through the PET base material to cure the composition 1 for light wavelength conversion layer. Then, the cured composition 1 for the light wavelength conversion layer was peeled off from the molding die rotating with the PET base material to obtain a light wavelength conversion layer having a lens portion. The lens portion is arranged side by side on the sheet-shaped main body portion, and extends in a direction intersecting the arrangement direction, and has a vertical angle of 90 °, a width of 50 μm, and a height. Had a plurality of triangular prism-shaped unit prisms having a size of 25 μm. Finally, the PET substrate was peeled off from the light wavelength conversion layer to obtain a light wavelength conversion sheet having a lens portion and composed of only the light wavelength conversion layer. The thickness of the light wavelength conversion sheet according to Example 5 was 125 μm.

<Example 6>
In Example 6, a light wavelength conversion sheet was produced in the same manner as in Example 5 except that the composition 2 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 7>
First, a prism sheet was prepared. The prism sheet was produced as follows. A molding die having a concave portion having an inverse shape to the desired shape of a unit prism and a rotating molding die had 99 parts by mass of an epoxy acrylate (product name "Unidick V-5500", manufactured by DIC) and a photopolymerization initiator (1 -Hydroxycyclohexyl phenyl ketone, product name "Irgacure (registered trademark) 184", manufactured by BASF Japan Ltd.) 1 part by mass of the composition for prism layer is coated and filled, and then this is a light-transmissive substrate having a thickness of 50 μm. A polyethylene terephthalate (PET) base material (product name "Lumirror T60", manufactured by Toray Industries, Inc.) was supplied at a running speed of 10 m / min and pressed onto the molding die from above the prism layer composition on the die surface. Then, in the pressed state, the composition for the prism layer was irradiated with ultraviolet rays through the PET base material to cure the composition for the prism layer. Then, the cured prism layer composition was peeled off from the molding die rotating together with the PET substrate to obtain a prism sheet. The prism sheet is arranged side by side with a sheet-shaped main body, and each extends in a direction intersecting with the arrangement direction, has an apex angle of 90 °, a width of 50 μm, and a height. Had a plurality of triangular prism-shaped unit prisms having a size of 25 μm.

The light wavelength conversion sheet (light wavelength conversion layer) according to Example 1 was arranged on the surface of the prism sheet opposite to the lens surface via an ultraviolet curable adhesive. Then, the ultraviolet ray-curable adhesive is cured by irradiating the ultraviolet ray from the prism sheet side so that the integrated light amount becomes 500 mJ / cm ² , and a light wavelength conversion sheet including a light wavelength conversion layer, an adhesive layer, and a prism sheet is obtained. Obtained. The thickness of the light wavelength conversion sheet according to Example 7 was 180 μm.

<Example 8>
In Example 8, a light wavelength conversion sheet was produced in the same manner as in Example 7 except that the light wavelength conversion sheet according to Example 2 was used instead of the light wavelength conversion sheet according to Example 1.

<Example 9>
The composition for light wavelength conversion layer 1 was applied to the surface opposite to the lens surface of the prism sheet having the same size as in Example 7 and produced in the same procedure as in Example 7, and the coating film was applied. Formed. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain a light wavelength conversion layer. Thereby, a light wavelength conversion sheet including the light wavelength conversion sheet and the prism sheet was obtained. The thickness of the light wavelength conversion sheet according to Example 9 was 175 μm.

<Example 10>
In Example 10, a light wavelength conversion sheet was produced in the same manner as in Example 9 except that the composition 2 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 11>
First, the light wavelength conversion layer composition 1 was applied to one surface of the PET substrate to form a coating film. Then, a polyethylene terephthalate (PET) film having a coating film was produced according to the same procedure as in Example 7, and the film was in contact with the surface of the prism sheet having the same size as in Example 7 opposite to the lens surface. A base material (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) was placed. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain a light wavelength conversion layer. Finally, the PET substrate was peeled off to obtain a light wavelength conversion sheet including a light wavelength conversion sheet and a prism sheet. The thickness of the light wavelength conversion sheet according to Example 11 was 175 μm.

<Example 12>
In Example 12, a light wavelength conversion sheet was produced in the same manner as in Example 11 except that the composition 2 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 13>
Composition 1 for overcoat layer was applied to one surface of the light wavelength conversion layer (light wavelength conversion layer) produced in Example 1 to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain an overcoat layer having a film thickness of 5 μm. Then, similarly, the composition 1 for the overcoat layer was applied to the other surface of the light wavelength conversion layer to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain an overcoat layer having a film thickness of 5 μm. Thereby, a light wavelength conversion sheet including the light wavelength conversion layer and the overcoat layers formed on both surfaces of the light wavelength conversion layer was obtained.

<Example 14>
In Example 14, a light wavelength conversion sheet was produced in the same manner as in Example 13 except that Composition 2 for overcoat layer was used instead of Composition 1 for overcoat layer.

<Comparative Example 1>
In Comparative Example 1, a light wavelength conversion sheet was produced in the same manner as in Example 1 except that the composition 3 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Comparative example 2>
In Comparative Example 2, a light wavelength conversion sheet was produced in the same manner as in Example 3 except that the light wavelength conversion layer composition 3 was used instead of the light wavelength conversion layer composition 1.

<Comparative example 3>
In Comparative Example 3, a light wavelength conversion sheet was produced in the same manner as in Example 5 except that the light wavelength conversion layer composition 3 was used instead of the light wavelength conversion layer composition 1.

<Comparative example 4>
In Comparative Example 4, a light wavelength conversion sheet was produced in the same manner as in Example 7, except that the composition 3 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Comparative Example 5>
In Comparative Example 5, a light wavelength conversion sheet was produced in the same manner as in Example 9 except that the composition 3 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Comparative example 6>
In Comparative Example 6, a light wavelength conversion sheet was produced in the same manner as in Example 11 except that the light wavelength conversion layer composition 3 was used instead of the light wavelength conversion layer composition 1.

<Comparative Example 7>
In Comparative Example 7, a light wavelength conversion sheet was produced in the same manner as in Example 13 except that the light wavelength conversion layer composition 3 was used instead of the light wavelength conversion layer composition 1.

<Comparative Example 8>
First, two barrier films were produced by the following method. In a high frequency sputtering device, a high frequency power of 13.56 MHz and a power of 5 kW was applied to the electrodes to generate discharge in the chamber, and a polyethylene terephthalate (PET) substrate (product name "Lumirror T60", manufactured by Toray Industries, Inc. ) Is formed on one surface thereof with a vapor-deposited silica layer having a target material (silica) having a thickness of 50 nm and a refractive index of 1.46, thereby forming a barrier film comprising a PET substrate and a silica vapor deposition layer. One sheet was formed.

Next, the light wavelength conversion layer composition 3 was applied to the silica vapor deposition layer side of one barrier film to form a coating film. Next, the formed coating film was dried by passing dry air at 80 ° C. for 30 seconds to evaporate the solvent in the coating film. Then, the other barrier film is arranged so that the silica vapor deposition layer is in contact with the coating film surface, and the coating film is cured by irradiating with ultraviolet rays so that the integrated light amount becomes 500 mJ / cm ² , and thereby the film thickness is 100 μm. The light wavelength conversion layer was formed to obtain a light wavelength conversion sheet having a thickness of 200 μm and including the barrier film and the light wavelength conversion layer arranged between the barrier films.

<Comparative Example 9>
In Comparative Example 9, a light wavelength conversion sheet was produced in the same manner as in Example 7 except that the light wavelength conversion sheet according to Comparative Example 8 was used instead of the light wavelength conversion sheet according to Example 1. The thickness of the light wavelength conversion sheet according to Comparative Example 9 was 280 μm.

<Example 15>
The composition 1 for the light diffusion layer is formed on one surface of two polyethylene terephthalate (PET) base materials (product name "Lumirror T60", manufactured by Toray Industries, Inc.) having a size of 7 inches and a thickness of 50 μm as light transmissive base materials. Was applied to form a coating film. Next, the formed coating film was dried by passing dry air at 80 ° C. for 30 seconds to evaporate the solvent in the coating film. After that, the coating film was cured by irradiating with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to form a light diffusion layer having a film thickness of 10 μm, and thus a PET substrate with a light diffusion layer was formed.

Then, the light wavelength conversion layer composition 4 was applied to the surface of the one PET substrate with the light diffusion layer opposite to the surface on the light diffusion layer side and dried at 80 ° C. to form a coating film. Then, the other PET base material with a light diffusion layer was laminated on the coating film so that the surface on the side opposite to the surface on the light diffusion layer side of the PET base material with a light diffusion layer was in contact. In this state, the coating film is cured by irradiating it with ultraviolet light so that the integrated light amount becomes 500 mJ / cm ² , to form a light wavelength conversion layer, and at the same time, a light wavelength conversion layer and two PET groups with a light diffusion layer. Integrated with wood. Thereby, the light wavelength conversion sheet according to Example 15 was obtained.

<Example 16>
In Example 16, a light wavelength conversion sheet was produced in the same manner as in Example 15, except that the composition 5 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 17>
In Example 17, a light wavelength conversion sheet was produced in the same manner as in Example 15, except that the composition 6 for light wavelength conversion layer was used instead of the composition 1 for light wavelength conversion layer.

<Example 18>
In Example 18, a light wavelength conversion sheet was produced in the same manner as in Example 15 except that the light wavelength conversion layer composition 7 was used in place of the light wavelength conversion layer composition 1.

<Example 19>
In Example 19, a light wavelength conversion sheet was produced in the same manner as in Example 15, except that the composition for light wavelength conversion layer 8 was used instead of the composition for light wavelength conversion layer 1.

<Example 20>
In Example 20, a light wavelength conversion sheet was produced in the same manner as in Example 15, except that the composition for light wavelength conversion layer 9 was used in place of the composition for light wavelength conversion layer 1.

<Example 21>
In Example 21, a light wavelength conversion sheet was produced in the same manner as in Example 15, except that the composition for light wavelength conversion layer 10 was used instead of the composition for light wavelength conversion layer 1.

<Example 22>
The light wavelength conversion layer composition 9 is applied to one surface of a polyethylene terephthalate (PET) base material (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) having a thickness of 50 μm and dried at 80 ° C. to form a coating film. Formed. Then, the coating film was cured by irradiating with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² . Finally, the PET substrate was peeled off to obtain a light wavelength conversion sheet according to Example 22 having only a light wavelength conversion layer having a thickness of 100 μm.

<Example 23>
A 100 μm-thick polyethylene terephthalate (PET) substrate (product name “Lumirror T60”, manufactured by Toray Industries, Inc.) was evenly coated with a prism layer composition containing urethane acrylate to form a prism layer composition. A coating film was formed to form a prism sheet laminate. Then, the laminate for prism sheet is provided with a traveling speed such that a coating mold of the composition for lens layer is provided on the rotating molding die with a concave portion having an inverse shape to the shape of the desired unit prism. It is supplied at 20 m / min to form the shape of the unit prism on the coating film of the composition for prism layer by the molding die, and the coating film of the composition for prism layer is irradiated with ultraviolet rays through the PET base material. The coating film of the composition for prism layer was cured. Finally, the cured coating film of the prism layer composition was peeled from the molding die together with the PET base material to obtain a prism sheet having a prism layer formed on one surface of the PET base material. The prism layer is arranged side by side with a sheet-shaped main body, and each extends in a direction intersecting with the arrangement direction, has an apex angle of 90 °, a width of 47 μm, and a height. Had a plurality of triangular prism-shaped unit prisms having a diameter of 30 μm.

Then, the light wavelength conversion layer composition 9 was applied to the other surface of the PET substrate in the prism sheet, and dried at 80 ° C. to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to form a light wavelength conversion layer having a film thickness of 100 μm integrated with the prism sheet. Thereby, the light wavelength conversion sheet according to Example 23 was obtained.

<Example 24>
Composition 1 for overcoat layer was applied to one surface of the light wavelength conversion sheet (light wavelength conversion layer) produced in Example 22 to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain an overcoat layer having a film thickness of 5 μm. Then, similarly, the composition 1 for the overcoat layer was applied to the other surface of the light wavelength conversion layer to form a coating film. Then, the coating film was cured by irradiating it with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to obtain an overcoat layer having a film thickness of 5 μm. Thereby, a light wavelength conversion sheet including the light wavelength conversion layer and the overcoat layers formed on both surfaces of the light wavelength conversion layer was obtained.

<Example 25>
In Example 25, a light wavelength conversion sheet was produced in the same manner as in Example 24, except that the overcoat layer composition 2 was used instead of the overcoat layer composition 1.

<Comparative Example 10>
In Comparative Example 10, a light wavelength conversion sheet was produced in the same manner as in Example 15 except that the light wavelength conversion layer composition 11 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 11>
In Comparative Example 11, a light wavelength conversion sheet was produced in the same manner as in Example 15 except that the light wavelength conversion layer composition 12 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 12>
In Comparative Example 12, a light wavelength conversion sheet was produced in the same manner as in Example 22 except that the light wavelength conversion layer composition 11 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 13>
In Comparative Example 13, a light wavelength conversion sheet was produced in the same manner as in Example 22 except that the light wavelength conversion layer composition 12 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 14>
In Comparative Example 14, a light wavelength conversion sheet was produced in the same manner as in Example 23, except that the light wavelength conversion layer composition 11 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 15>
In Comparative Example 15, a light wavelength conversion sheet was produced in the same manner as in Example 23, except that the light wavelength conversion layer composition 12 was used in place of the light wavelength conversion layer composition 1.

<Comparative Example 16>
In Comparative Example 16, a light wavelength conversion sheet was produced in the same manner as in Example 24, except that the light wavelength conversion layer composition 11 was used in place of the light wavelength conversion layer composition 9.

<Comparative Example 17>
In Comparative Example 17, a light wavelength conversion sheet was produced in the same manner as in Example 24, except that the light wavelength conversion layer composition 12 was used in place of the light wavelength conversion layer composition 9.

<Comparative Example 18>
First, two barrier films were produced by the following method. In a high-frequency sputtering device, by applying high-frequency power having a frequency of 13.56 MHz and a power of 5 kW to electrodes, a discharge is generated in the chamber, and polyethylene terephthalate as a light-transmissive base material having a size of 7 inches and a thickness of 50 μm. On one surface of a (PET) substrate (product name “Lumirror T60”, manufactured by Toray Industries, Inc.), a silica vapor deposition layer made of a target substance (silica) having a thickness of 50 nm and a refractive index of 1.46 was formed. Thereby, two barrier films each having a silica vapor deposition layer formed on one surface of the PET substrate were formed.

Next, the composition 1 for a light diffusion layer was applied to the surface of both barrier films opposite to the surface on the side of the vapor-deposited silica to form a coating film. Next, the formed coating film was dried by passing dry air at 80 ° C. for 30 seconds to evaporate the solvent in the coating film. Then, the coating film was cured by irradiating with ultraviolet rays so that the integrated light amount was 500 mJ / cm ² , to form a light diffusion layer having a film thickness of 10 μm, and thus a barrier film with a light diffusion layer was formed.

Next, the light wavelength conversion layer composition 11 was applied to the silica vapor deposition layer side of one of the barrier films with a light diffusion layer, and dried at 80 ° C. to form a coating film. Then, the other barrier film with a light diffusion layer was laminated so that the silica deposition layer was in contact with the surface of the silica vapor deposition layer of the barrier film with a light diffusion layer in the coating film. In this state, the coating film is cured by irradiating it with ultraviolet rays so that the integrated light amount becomes 500 mJ / cm ² , thereby forming a light wavelength conversion layer having a thickness of 100 μm, which is in close contact with both barrier films with a light diffusion layer. did. Thereby, a light wavelength conversion sheet according to Comparative Example 18 was obtained.

<Comparative Example 19>
In Comparative Example 19, a light wavelength conversion sheet was produced in the same manner as in Comparative Example 18 except that the light wavelength conversion layer composition 12 was used instead of the light wavelength conversion layer composition 1.

<Measurement of water vapor transmission rate and oxygen transmission rate>
In the light wavelength conversion sheets according to the above-mentioned example and the above-mentioned comparative example, the water vapor transmission rate and the oxygen transmission rate were measured. For the water vapor transmission rates of the light wavelength conversion sheets according to Examples 1 to 14 and Comparative Examples 1 to 9, a water vapor transmission rate measurement device (product name “DELTAPERM”, manufactured by Technolox Corporation) was used in accordance with JIS K7129: 2008. And measured under the conditions of 40 ° C. and 90% relative humidity. The water vapor transmission rates of the light wavelength conversion sheets according to Examples 15 to 25 and Comparative Examples 10 to 19 are in accordance with JIS K7129: 2008, and a water vapor transmission rate measuring device (product name “PERMATRAN-W3 / 31”, MOCON Company). Manufactured by K.K.) and measured at 40 ° C. and 90% relative humidity. In addition, the oxygen transmittances of the light wavelength conversion sheets according to Examples 1 to 14 and Comparative Examples 1 to 9 are based on JIS K7126: 2006, and an oxygen gas transmittance measuring device (product name “OX-TRAN 2/21 , Manufactured by MOCON) at 23 ° C. and a relative humidity of 90%. The oxygen transmittances of the light wavelength conversion sheets according to Examples 15 to 25 and Comparative Examples 10 to 19 are based on JIS K7126: 2006, and an oxygen gas transmittance measuring device (product name “OX-TRAN 2/20”, It was measured under the conditions of 23 ° C. and 90% relative humidity.

<Number of quantum dots and distance measurement>
In the light wavelength conversion sheets according to Examples 1 to 14, 20 cross sections of light wavelength conversion particles were randomly photographed using a scanning transmission electron microscope (STEM), and one light was obtained from the image of the obtained cross section. The number of quantum dots contained in the wavelength conversion particles was calculated, and the average value of the calculated number of quantum dots was calculated. Similarly, in the light wavelength conversion sheets according to Examples 1 to 14, the cross sections of 20 light wavelength conversion particles were randomly photographed using a scanning transmission electron microscope (STEM), and images of the obtained cross sections were obtained. Then, the distance between the quantum dots was calculated, and the average value of the calculated distances between the quantum dots was calculated.

<Measurement of content of specific element by fluorescent X-ray analysis>
In the light wavelength conversion sheets according to Examples 15 to 25 and Comparative Examples 10 to 18, the content of sulfur, phosphorus, and nitrogen contained in the light wavelength conversion layer was measured by fluorescent X-ray analysis with the PET substrate removed. The measurement was performed using an apparatus (product name "RIX2000 type", manufactured by Rigaku Corporation). When two or three elements of sulfur, phosphorus and nitrogen were detected from the light wavelength conversion layer, the content was the total content of these elements.

<Quantity dot deterioration suppression function judgment test in light wavelength conversion layer>
With respect to the light wavelength conversion sheets according to Examples 1 to 25 and Comparative Examples 1 to 7 and 10 to 16, a deterioration resistance test was performed, and from the luminance change rate of the central portion of the light wavelength conversion sheet before and after the deterioration resistance test. Then, it was investigated whether or not the light wavelength conversion layer has a function of suppressing deterioration of the quantum dots. Specifically, first, each of the light wavelength conversion layer sheets was incorporated into a backlight device in a state where a deterioration resistance test of leaving it for 100 hours under conditions of 60 ° C. and 90% relative humidity was not performed. In the light wavelength conversion sheets according to Comparative Examples 8, 9, 17, and 18, since the light wavelength conversion sheet includes the barrier film, as shown in Table 1 and Table 3, 0.1 g / (m ^It shows a water vapor transmission rate of less than ² · 24 h) and an oxygen transmission rate of less than 0.1 cm ³ / (m ² · 24 h · atm). In the light wavelength conversion sheet exhibiting such low water vapor transmission rate and oxygen transmission rate, the light wavelength conversion layer has a deterioration suppressing function of the quantum dots from the change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet. Since it cannot be determined whether or not there is any, the light wavelength conversion sheets according to Comparative Examples 8, 9, 17, and 18 were not subjected to the test here.

  As a backlight device, a backlight device of Kindle Fire (registered trademark) HDX7 (a blue light emitting diode having an emission peak wavelength of 450 nm, a light guide plate, two prism sheets (first prism sheet and second prism sheet)) Was used. The two prism sheets each include a sheet-shaped main body portion and a plurality of triangular prism-shaped unit prisms arranged side by side on the main body portion and extending in a direction intersecting the arrangement direction. The angle was 90 °.

  Then, the light guide plate is arranged so that the blue light emitting diode side becomes the light entrance surface, and the light wavelength conversion sheet, the first prism sheet, and the second prism sheet according to the first embodiment are provided on the light exit surface of the light guide plate. By arranging in order, a backlight device incorporating the light wavelength conversion sheet according to Example 1 was obtained. The second prism sheet on the observer side was arranged so that the arrangement direction of the unit prisms was orthogonal to the arrangement direction of the unit prisms of the first prism sheet. Further, in the same manner, a backlight device incorporating the light wavelength conversion sheets according to Examples 2 to 25 and Comparative Examples 1 to 7 and 10 to 16 was obtained. However, in Examples 5 to 12 and 23 and Comparative Examples 3 to 7, 14 and 15, the first prism sheet was not used, and the lens portion or the prism sheet in the light wavelength conversion sheet should be on the observer side. The arrangement direction of the unit prisms is orthogonal to the arrangement direction of the unit prisms of the second prism sheet. The light emitting surface of the backlight device was the lens surface of the second prism sheet.

  With the light wavelength conversion sheet incorporated in the backlight device, the blue light emitting diode was turned on, and light was applied to the entire one surface of the light wavelength conversion sheet through the light guide plate. In this state, the brightness at the center of the light emitting surface corresponding to the center of the light wavelength conversion sheet was measured. The brightness was measured using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta) under the condition of a measurement angle of 1 °.

  Then, the light wavelength conversion sheets according to Examples 1 to 25 and Comparative Examples 1 to 7 and 10 to 16 are taken out from the backlight device and left standing for 100 hours under the conditions of 60 ° C. and relative humidity of 90%. A sex test was conducted. Then, the light wavelength conversion sheet after the deterioration resistance test is incorporated in the backlight device in the same manner as above, and in that state, under the same conditions as above, in the central portion of the light emitting surface corresponding to the central portion of the light wavelength conversion sheet. The brightness was measured.

From these measured luminances, the rate of change in luminance after the deterioration resistance test with respect to the luminance before the deterioration resistance test in the central portion of the light wavelength conversion sheet was obtained. Regarding the luminance change rate before and after the deterioration resistance test, the luminance change rate is D _1, and the brightness of the light emitted from the central portion of the light emitting surface of the backlight device before the deterioration resistance test is E ₁ and the deterioration resistance test is performed. The brightness of the light emitted from the central portion of the light emitting surface of the subsequent backlight device was defined as C ₁ and was calculated by the following formula. Then, if the rate of change in luminance was within ± 10%, it was determined that the light wavelength conversion layer had a quantum dot deterioration suppressing function.
D ₁ = (F ₁ −E ₁ ) / E ₁ × 100

<Brightness change before and after durability test of central part of light wavelength conversion sheet>
A durability test was conducted on the light wavelength conversion sheets according to the above-mentioned examples and the above-mentioned comparative examples, and the change in luminance at the central portion of the light wavelength conversion sheet before and after the durability test was examined. Specifically, first, each light wavelength conversion sheet was incorporated into a backlight device in a state where a durability test of leaving it for 500 hours under conditions of 60 ° C. and 90% relative humidity was not performed.

  The backlight device uses the same backlight device as the backlight device used in the deterioration suppressing function judgment test of the quantum dots in the light wavelength conversion layer, and the light wavelength conversion sheet according to the example and the comparative example, It was incorporated into a backlight device in the same manner as the test for determining the function of suppressing deterioration of quantum dots in the light wavelength conversion layer.

  With the light wavelength conversion sheet incorporated in the backlight device, the blue light emitting diode was turned on, and light was applied to the entire one surface of the light wavelength conversion sheet through the light guide plate. In this state, the brightness at the center of the light emitting surface corresponding to the center of the light wavelength conversion sheet was measured. The brightness was measured using a spectral radiance meter (product name “CS2000”, manufactured by Konica Minolta) under the condition of a measurement angle of 1 °.

  Then, the light wavelength conversion sheets according to the above-mentioned Examples and Comparative Examples were subjected to a durability test of leaving them for 500 hours under the conditions of 60 ° C. and 90% relative humidity. Then, the light wavelength conversion sheet after the durability test was incorporated into the backlight device in the same manner as above, and in that state, under the same conditions as above, the brightness in the central portion of the light emitting surface corresponding to the central portion of the light wavelength conversion sheet. Was measured.

From these measured luminances, the rate of change in luminance after the durability test with respect to the luminance before the durability test in the central portion of the light wavelength conversion sheet was obtained. Regarding the luminance change rate before and after the durability test, the luminance change rate was A ₁ , the luminance of the light emitted from the central part of the light emitting surface of the backlight device before the durability test was B _1, and the backlight after the durability test was performed. The brightness of the light emitted from the center of the light emitting surface of the light device was defined as C _1, and the brightness was calculated by the following formula.
A ₁ = (C ₁ −B ₁ ) / B ₁ × 100

<Measurement of deterioration width of peripheral edge of light wavelength conversion sheet>
Using the above-described backlight device incorporating the light wavelength conversion sheet after the durability test according to the above Examples and Comparative Examples, the luminance distribution on the light emitting surface during light emission in the backlight device, the thickness of the light wavelength conversion sheet From the direction, measurement was performed using a 2D color luminance meter (product name "UA-200", manufactured by Topcon Technohouse). Then, from the measured luminance distribution of the light emitting surface, a position where the luminance is 80% of the luminance of the central portion of the light emitting surface (luminance 80% position) is obtained, and the luminance is calculated from the edge closest to the luminance 80% position on the light emitting surface. The shortest distance to the 80% position was calculated. Then, this shortest distance was randomly determined at 20 locations, and the average value of the shortest distances at these 20 locations was used as the deterioration width of the peripheral portion of the light wavelength conversion sheet.

<Evaluation of dot-like luminance defects>
Using the above-mentioned backlight device incorporating the light wavelength conversion sheet after the durability test according to the above-mentioned examples and the above-mentioned comparative examples, whether there is a dot-like luminance defect on the light-emitting surface during light emission in the backlight device. It was visually observed and evaluated. The evaluation criteria are as follows.
◯: No dot-like luminance defect was confirmed, or a small amount was confirmed, but there was no problem in practical use.
X: Many point-like luminance defects were confirmed.

The results are shown below in Tables 1 to 4.

  In the light wavelength conversion sheets according to Comparative Examples 1 to 7, since the change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet was not within ± 10%, the light wavelength conversion layer was used to suppress deterioration of the quantum dots. It had no function. On the other hand, in the light wavelength conversion sheets according to Comparative Examples 1 to 7, the water vapor transmission rate and the oxygen transmission rate were high. For this reason, the quantum dots deteriorated by the durability test, and there was a large change in luminance in the central portion before and after the durability test. In the light wavelength conversion sheets according to Comparative Examples 1 to 7, the deterioration width of the peripheral portion is 0 mm. In the light wavelength conversion sheets according to Comparative Examples 1 to 7, the quantum dots were deteriorated as a whole. This is because there is almost no difference in luminance between the central portion and the peripheral portion of the light emitting surface.

  Since the light wavelength conversion sheets according to Comparative Examples 8 and 9 are provided with the barrier film, they have many spot-like luminance defects, and the water vapor transmission rate and the oxygen transmission rate are extremely low, but the deterioration width of the peripheral portion is small. It was great. Further, since the light wavelength conversion sheets according to Comparative Examples 8 and 9 were equipped with the barrier film, the thickness of the light wavelength conversion sheet was large.

  On the other hand, in the light wavelength conversion sheets according to Examples 1 to 14, since the change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet was within ± 10%, the light wavelength conversion layer was a quantum dot. It had a deterioration suppressing function. It is considered that this is because the light wavelength conversion particles were used. Therefore, in the light wavelength conversion sheets according to Examples 1 to 14, both the water vapor transmission rate and the oxygen transmission rate are high, but Examples 1 and 2 and Comparative Example 1, and Examples 3 and 4 and Comparative Example 2, Examples 5 and 6 and Comparative Example 3, Examples 7 and 8 and Comparative Example 4, Examples 9 and 10 and Comparative Example 5, Examples 11 and 12 and Comparative Example 6, and Examples 13 and 14 and Comparative Example 7. Comparing the brightness changes before and after the durability test in the central portion of the light wavelength conversion sheet, the light wavelength conversion sheets according to Examples 1 to 14 were compared to those in Comparative Examples 1 to 7 before and after the durability test. The change in brightness was small. Further, the deterioration width of the peripheral portion of the light wavelength conversion sheets according to Examples 1 to 14 was smaller than the deterioration width of the peripheral portion of the light wavelength conversion sheets according to Comparative Examples 8 and 9. Therefore, it was confirmed that the light wavelength conversion sheets according to Examples 1 to 14 can suppress the deterioration of the quantum dots without providing the barrier film. Further, since the light wavelength conversion sheets according to Examples 1 to 14 do not include a barrier film, no point-like luminance defect was confirmed, or a little was confirmed, but it is at a level with no practical problem. The thickness was extremely smaller than that of the light wavelength conversion sheets according to Comparative Examples 8 and 9.

  In the light wavelength conversion sheets according to Comparative Examples 10 to 17, since the change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet was not within ± 10%, the light wavelength conversion layer was used to suppress deterioration of the quantum dots. It had no function. On the other hand, in the light wavelength conversion sheets according to Comparative Examples 10 to 17, the water vapor transmission rate and the oxygen transmission rate were high. For this reason, the quantum dots were deteriorated by the durability test, and the brightness change in the central part before and after the durability test and the deterioration width of the peripheral part were large.

  In the light wavelength conversion sheets according to Comparative Examples 18 and 19, since the barrier film was provided, there were many spot-like luminance defects, and the water vapor transmission rate and the oxygen transmission rate were extremely low, but the deterioration width of the peripheral portion was small. It was great.

  On the other hand, in the light wavelength conversion sheets according to Examples 15 to 25, since the change in luminance before and after the deterioration resistance test in the light wavelength conversion sheet was within ± 10%, the light wavelength conversion layer was a quantum dot. It had a deterioration suppressing function. It is considered that this is because the content of the specific element in the light wavelength conversion layer measured by fluorescent X-ray analysis was 0.5% by mass or more. Therefore, in the light wavelength conversion sheets according to Examples 15 to 25, both the water vapor transmission rate and the oxygen transmission rate are high, but Examples 15 to 21 and Comparative Examples 10 and 11, and Example 22 and Comparative Example 12 and 13 and Example 23 and Comparative Examples 14 and 15, and Example 24 and 25 and Comparative Examples 16 and 17 are compared with each other in terms of the change in luminance before and after the durability test in the central portion and the deterioration width in the peripheral portion, respectively. The light wavelength conversion sheets according to Examples 15 to 25 had a smaller change in luminance before and after the durability test in the central portion and a smaller deterioration width at the peripheral portion than Comparative Examples 10 to 17. Further, the deterioration width of the peripheral portion of the light wavelength conversion sheets according to Examples 15 to 25 was smaller than the deterioration width of the peripheral portion of the light wavelength conversion sheets according to Comparative Examples 18 and 19. Therefore, it was confirmed that the light wavelength conversion sheets according to Examples 15 to 25 can suppress the deterioration of the quantum dots without providing the barrier film. In addition, since the light wavelength conversion sheets according to Examples 15 to 25 do not include the barrier film, no dot-like luminance defect was confirmed, or a small amount was confirmed, but there was no problem in practical use. Furthermore, the light wavelength conversion sheets according to Examples 15 to 23 can be made thinner than the light wavelength conversion sheets according to Comparative Examples 18 and 19 by at least the thickness of the barrier layer. Such a light wavelength conversion sheet had an extremely smaller thickness than the light wavelength conversion sheets according to Comparative Examples 18 and 19.

  Further, in the light wavelength conversion sheets according to Examples 13, 14, 24 and 25, a scratch test was performed on the overcoat layer, and the vertical force and the horizontal force at that time were measured. The light wavelength conversion sheets had a vertical force of 21 μN and a horizontal force of −11 μN, and the light wavelength conversion sheets according to Examples 14 and 25 had a vertical force of 11 μN and a horizontal force of −6 μN. It was These overcoat layers were dense films and had the ability to prevent the light wavelength conversion layer from being exposed to the atmosphere. However, in terms of the ability to prevent the light wavelength conversion layer from being exposed to the air, the light wavelength conversion according to Examples 13 and 24 was performed. It can be said that the overcoat layer of the sheet is higher than the overcoat layer of the light wavelength conversion sheets according to Examples 14 and 25. In the scratch test, an indenter (Cube Corner: Ti037_110410 (12)) was applied from the cross section of the overcoat layer to the inside of the overcoat layer by using a nanoindentation device (product name “TI950 TriboIndenter”, manufactured by HYSITRON (Heiditron) Co., Ltd.). ) Was pushed in 50 nm, the depth was kept constant, and this indenter was moved in the horizontal direction at a moving speed of 4 μm / min for 30 seconds, and the vertical force (load) and horizontal force at that time were measured and measured. The average value of the vertical force and the horizontal force was obtained, and the average value of the five average values of the vertical force (5 times average value) obtained by repeating this scratch test 5 times was taken as the vertical force. The average value of the average values (average value of 5 times) was defined as the horizontal force.

  Although CdSe is used as the core material of the green light emitting quantum dots and the red light emitting quantum dots in the above-mentioned embodiment, the same as in the above embodiment even if a non-Cd-based material such as InP or InAs is used as the core material. The result was obtained.

10, 20, 30, 40, 50, 130 ... Light wavelength conversion sheet 11, 31, 131 ... Light wavelength conversion layer 12, 136 ... Binder resin 13 ... Light wavelength conversion particle 14, 138 ... Light scattering particle 15, 137 ... Quantum Dots 16 ... Barrier particles 32 ... Lens part 41 ... Light control sheets 51, 52 ... Overcoat layer 60 ... Image display devices 70, 120 ... Backlight device 110 ... Display panel

Claims (26)

A light wavelength conversion sheet,
And a binder resin, said binder resin dispersed quantum dots, and the wrapped quantum dots, and moisture and oxygen including the optical wavelength converting layer and the light wavelength converting particles transmission consisting of suppressing light-permeable barrier particles of Equipped with
The barrier particles are inorganic oxide particles,
The surface of the quantum dot is in close contact with the barrier particles,
Water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet is 0.1 g / (m ² · 24 h) or more and / or oxygen transmission at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet. A light wavelength conversion sheet having a rate of 0.1 cm ³ / (m ² · 24h · atm) or more. The light wavelength conversion sheet according to claim 1 , wherein each of the light wavelength conversion particles includes one or more and 50 or less of the quantum dots. The light wavelength conversion particles each include two or more quantum dots, and the quantum dots included in one light transmissive particle have an average distance between the quantum dots of 1 nm or more. The light wavelength conversion sheet according to claim 1 or 2 . The light wavelength conversion sheet according to any one of claims 1 to 3, wherein an average particle diameter of the light wavelength conversion particles is 10 nm or more and 500 nm or less. The quantum dots is two or more quantum dots having an emission band of the respective wavelength ranges of the sole, and includes the optical wavelength conversion particles per 2 or more types of quantum dots, one of claims 1 to 4 one The optical wavelength conversion sheet according to the item . The quantum dots is two or more quantum dots having an emission band of the respective wavelength ranges of the sole, and comprising said one quantum dot per optical wavelength converting particles, any one of claims 1 to 4 The light wavelength conversion sheet described in. The light wavelength conversion sheet according to any one of claims 1 to 6, wherein the light wavelength conversion sheet is composed of only a light wavelength conversion layer including a lens portion. A light wavelength conversion sheet,
A binder resin and an optical wavelength conversion layer containing quantum dots dispersed in the binder resin,
Sulfur and phosphorus of the optical wavelength conversion layer that is measured by a fluorescent X-ray analysis, sulfur and nitrogen, phosphorus and nitrogen, sulfur, phosphorus and nitrogen, phosphorus or der content above 0.5 mass% of nitrogen, Ri ,
Water vapor transmission rate at 40 ° C. and 90% relative humidity in the light wavelength conversion sheet is 0.1 g / (m ² · 24 h) or more and / or oxygen transmission at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet. A light wavelength conversion sheet having a rate of 0.1 cm ³ / (m ² · 24h · atm) or more . The light wavelength conversion sheet according to claim 8 , wherein the binder resin contains sulfur and phosphorus, sulfur and nitrogen, phosphorus and nitrogen, sulfur and phosphorus and nitrogen, phosphorus, or nitrogen. A light wavelength conversion sheet,
A binder resin and an optical wavelength conversion layer containing quantum dots dispersed in the binder resin,
The content of one or more elements selected from the group consisting of sulfur, phosphorus, and nitrogen in the light wavelength conversion layer measured by fluorescent X-ray analysis is 0.5% by mass or more,
The light wavelength conversion sheet has a water vapor transmission rate of 0.1 g / (m at 40 ° C. and a relative humidity of 90%. ² 24 hours or more and / or oxygen transmittance at 23 ° C. and 90% relative humidity in the light wavelength conversion sheet is 0.1 cm. ^Three / (M ² ・ 24h ・ atm) or more,
The light wavelength conversion sheet, wherein the light wavelength conversion sheet comprises only a light wavelength conversion layer. At least one cover surface, further comprising an overcoat layer comprising a resin, the optical wavelength conversion sheet according to any one of claims 1 to 10 for the optical wavelength conversion layer.   The light wavelength conversion sheet according to claim 11, wherein the overcoat layer has a hardness such that a vertical force is 10 µN or more and / or a horizontal force is -5 µN or less in a scratch test. Before and after a durability test in which the light wavelength conversion sheet is left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours, a predetermined wavelength conversion is performed by the quantum dots on one surface of the light wavelength conversion sheet. When the brightness of the light emitted from the central portion of the other surface of the light wavelength conversion sheet is measured by irradiating the light amount of light, the change in the brightness after the durability test with respect to the brightness before the durability test. The light wavelength conversion sheet according to any one of claims 1 to 12, wherein the ratio is within ± 10%.   14. The light according to claim 13, wherein a deterioration width of a peripheral portion of the light wavelength conversion sheet is 5 mm or less after a durability test in which the light wavelength conversion sheet is left in an environment of 60 ° C. and a relative humidity of 90% for 500 hours. Wavelength conversion sheet. The light wavelength conversion sheet according to claim 1, wherein the light wavelength conversion layer further contains light scattering particles. The light wavelength conversion sheet is composed of only the optical wavelength conversion layer, the light wavelength conversion sheet according to claim 1 or 8. The light further comprising an optical member on at least one surface side of the wavelength conversion layer, and the optical member and the optical wavelength conversion layer are integrated without using the air layer, the light according to claim 1 or 8 Wavelength conversion sheet. A light source,
And an optical wavelength conversion sheet according to any one of claims 1 to 17 receives light from the light source, the backlight device. A backlight device according to claim 18 ,
An image display device, comprising: a display panel disposed on a light emitting side of the backlight device. It is a manufacturing method of the light wavelength conversion sheet according to claim 1 ,
A composition for light wavelength conversion layer comprising a curable binder resin precursor, a quantum dot, and a light wavelength conversion particle consisting of a light-transmissive barrier particle that surrounds the quantum dot and suppresses the transmission of moisture and oxygen. Coating on one surface of the substrate, to form a coating film of the composition for light wavelength conversion layer, and curing the coating film, comprising the step of forming a light wavelength conversion layer ,
Wherein the barrier particles, Ru Oh inorganic oxide particles, the light wavelength conversion sheet manufacturing method of. It is a manufacturing method of the light wavelength conversion sheet according to claim 8 ,
A curable binder resin precursor containing a sulfur compound and a phosphorus compound, a sulfur compound and a nitrogen compound, a phosphorus compound and a nitrogen compound, a sulfur compound and a phosphorus compound and a nitrogen compound, a phosphorus compound or a nitrogen compound, and a polymerizable compound, and a quantum. A light wavelength conversion layer composition containing dots is applied to one surface of a substrate to form a coating film of the light wavelength conversion layer composition, and the coating film is cured to form a light wavelength conversion layer. A method for manufacturing a light wavelength conversion sheet, comprising the step of forming.   22. The method according to claim 20, further comprising a step of peeling the base material from the light wavelength conversion layer after forming the light wavelength conversion layer to obtain a light wavelength conversion sheet composed of only the light wavelength conversion layer. Manufacturing method.   After forming the light wavelength conversion layer, the method further comprises a step of bonding an optical member to the first surface, which is a surface opposite to the surface on the base material side of the light wavelength conversion layer, via an adhesive layer, The method for manufacturing a light wavelength conversion sheet according to claim 20 or 21.   Before or after attaching the optical member to the first surface of the light wavelength conversion layer, a step of peeling the base material from the light wavelength conversion layer, and the light wavelength after peeling the base material The light wavelength conversion sheet according to claim 23, further comprising a step of bonding an optical member different from the optical member to the second surface of the conversion layer opposite to the first surface via an adhesive layer. Manufacturing method.   The optical wavelength conversion according to claim 20 or 21, wherein an optical member is arranged on the application surface of the coating film after the composition for the optical wavelength conversion layer is applied to the base material and before the coating film is cured. Sheet manufacturing method.   22. The substrate is a light transmissive substrate, and the coating film is cured with a light transmissive substrate different from the substrate in contact with the coating surface of the coating film. The method for producing a light wavelength conversion sheet according to.

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