TW202123496A - Light emitting device - Google Patents

Abstract

The purpose of the present invention is to provide a light emitting device that can emit white light, and that is configured such that the manufacturing cost for a wavelength conversion member can be suppressed. A light emitting device (1) according to the present invention comprises a light emitting element (2) and a wavelength conversion sheet (3) disposed on the light-radiating side of the light emitting element, the light emitting device being characterized in that: the light emitting element is adjusted so as to be able to produce colored light resulting from mixing non-blue visible light with blue light; the wavelength conversion member includes red fluorescent particles and green fluorescent particles; and light from the light emitting element is emitted as white light via the wavelength conversion member.

Description

Light-emitting device

The present invention relates to a light-emitting device that causes light from a light-emitting element to emit white light through a wavelength conversion member.

Quantum dots are nano-particles composed of hundreds to thousands of atoms with a particle size of several nanometers to several tens of nanometers. Quantum dots are also called fluorescent nanoparticles, semiconductor nanoparticles, or nanocrystals.

As described in Patent Document 1 below, quantum dots are dispersed in a resin to constitute a wavelength conversion member. The wavelength conversion component is arranged on an LED (Light Emitting Diode) chip that emits blue light. Quantum dots include quantum dots with fluorescent wavelengths of red or green. Part of the blue light emitted from the light-emitting element is converted into green and green by the quantum dots, and white light can be emitted from the surface of the wavelength conversion member. Prior art literature Non-patent literature

Patent Document 1: International Publication No. 2015/156226

[The problem to be solved by the invention]

The wavelength conversion member is formed in a sheet shape, for example, and an increase in the number of quantum dots included in the wavelength conversion member causes a problem that the manufacturing cost of the wavelength conversion member becomes higher.

In addition, when the light emitted from the light-emitting element is wavelength-converted by the wavelength conversion member, there is a problem of color unevenness or uneven brightness (halo phenomenon) due to diffusion and diffuse reflection at a diffuser or the like.

The present invention was completed in view of the above-mentioned aspects, and its object is to provide a light-emitting device which can control the manufacturing cost of the wavelength conversion member and can emit white light. [Technical means to solve the problem]

The light-emitting device of the present invention is characterized in that it is provided with a light-emitting element and a wavelength conversion member arranged on the light-emitting side of the light-emitting element, and the light-emitting element is adjusted to produce blue light and mixed with visible light other than blue. The wavelength conversion member includes red fluorescent particles and green fluorescent particles, and the light from the light-emitting element emits white light through the wavelength conversion member.

In the present invention, it is preferable that the light-emitting element is adjusted so that the blue light is mixed with red light and green light whose luminous intensity is weaker than that of the blue light. In the present invention, the above-mentioned wavelength conversion member is preferably in a sheet shape.

In the present invention, it is preferable that a plurality of the light-emitting elements are arranged in a matrix so that the light-emitting elements to be emitted can be selected, and the color light from one or more of the light-emitting elements passes through the wavelength conversion member. The surface of the wavelength conversion member emits white light.

In the present invention, it is preferable that the above-mentioned wavelength conversion member is coated or bonded to the surface of the partially reflective sheet.

The light-emitting device of the present invention is characterized in that it includes a light-emitting element and a wavelength conversion member disposed on the light emitting side of the light-emitting element, the wavelength conversion member includes red fluorescent particles and green fluorescent particles, and the wavelength conversion member It is coated or attached to the surface of the partially reflective sheet, and the light from the light-emitting element emits white light through the wavelength conversion member. [Effects of Invention]

According to the first light-emitting device of the present invention, the light-emitting element is adjusted to emit light formed by mixing blue light with visible light other than blue, thereby reducing the red fluorescent particles and green fluorescent particles contained in the wavelength conversion member. The content of light particles.

According to the second light-emitting device of the present invention, by disposing the wavelength conversion member on the partially reflective sheet, it is possible to suppress color unevenness or brightness unevenness (halo phenomenon).

The invention can control the manufacturing cost of the wavelength conversion component and can emit white light.

<First Embodiment> Although there is a known light-emitting device in which a wavelength conversion member containing quantum dots is arranged on the surface of a blue LED to convert the wavelength of blue light emitted by the LED into white light, if the wavelength conversion member is made into a sheet shape, it can be enlarged. , The amount of quantum dots used for wavelength conversion components increases, which causes the problem of high manufacturing costs.

In this regard, the inventors of the present invention mixed blue light and visible light other than blue light emitted from light-emitting elements such as LEDs, thereby realizing a reduction in the amount of fluorescent particles used in the wavelength conversion member.

That is, the light-emitting device of the first embodiment has the following characteristics. (1) A light emitting element and a wavelength conversion member arranged on the light emitting side of the light emitting element are provided. (2) The light-emitting element is adjusted so that it can produce blue light mixed with visible light other than blue. (3) The wavelength conversion member includes red fluorescent particles and green fluorescent particles. (4) The light from the light emitting element emits white light through the wavelength conversion member.

FIG. 1 is a schematic cross-sectional view of the light-emitting device of this embodiment. FIG. 2 is a schematic plan view of the light-emitting device of this embodiment. FIG. 3 is a schematic diagram of the quantum dot of this embodiment.

The light-emitting device 1 shown in FIG. 1 includes a light-emitting element 2 and a wavelength conversion sheet (wavelength conversion member) 3 (the above (1)). The light-emitting element 2 is, for example, an LED chip, and a plurality of light-emitting elements 2 are arranged on the substrate 4. As shown in FIG. 2, the light-emitting elements 2 are arranged in a matrix in the X and Y directions orthogonal to each other.

As shown in FIG. 1, a diffuser 5, a wavelength conversion sheet 3, and various optical sheets 6 and 7 are laminated on the light emitting side (upward direction in the figure) of each light emitting element 2 at a predetermined interval. The optical sheets 6 and 7 are brightness-increasing films, lenses, etc., but are not particularly limited.

In the present embodiment, the light-emitting element 2 is adjusted so as to be able to produce blue light mixed with visible light other than blue (the above (2)). Here, the light L1 emitted from the light-emitting element 2 is, for example, blue light mixed with yellow light, or blue light mixed with red light or green light. As the light-emitting element 2, for example, a combination of a blue LED with a yellow phosphor, a blue LED with a combination of a red phosphor and a green phosphor, and the like are used. In addition, it is preferable that the blue light emitted from the light-emitting element 2 is mixed with red light and green light whose intensity is weaker than that of blue light.

In this embodiment, by the above-mentioned color mixing, near white light (substantially white light) can be emitted from the light-emitting element 2. Here, the so-called "near white light" refers to light that is close to white light, such as reddish white light, yellowish white light, bluish white light, or greenish white light.

In this embodiment, the wavelength conversion sheet 3 contains red fluorescent particles and green fluorescent particles (the above (3)). Here, the fluorescent particles are preferably quantum dots.

The composition and material of the quantum dots are not limited. For example, the quantum dots in this embodiment are nano particles with a particle size of several nm to several tens of nm.

For example, quantum dots are CdS, CdSe, ZnS, ZnSe, ZnSeS, ZnTe, ZnTeS, Ag ₂ Te, AgInTe, etc. Here, the quantum dot preferably does not contain Cd and does not contain P. Cd restricts its use in various countries due to its toxicity. In addition, organophosphorus compounds are expensive and easily oxidized in the air, making synthesis unstable, which easily leads to increased costs, unstable fluorescent characteristics, and complicated manufacturing steps.

In this embodiment, since the content of quantum dots can be reduced, even if quantum dots containing Cd are used, the amount of Cd contained in the wavelength conversion sheet 3 can be reduced.

As shown in FIG. 3A, it is preferable that many organic ligands 11 are coordinated on the surface of the quantum dot 10. Thereby, the aggregation of quantum dots can be suppressed, and the target optical characteristics can be exhibited. The ligands that can be used in the reaction are not particularly limited. For example, the following ligands can be cited as representative ligands.

(1) Aliphatic primary amine oleylamine: C ₁₈ H ₃₅ NH ₂ , stearyl (octadecyl) amine: C ₁₈ H ₃₇ NH ₂ , dodecyl (lauryl) amine: C ₁₂ H ₂₅ NH ₂ , decylamine: C ₁₀ H ₂₁ NH ₂ , octylamine: C ₈ H ₁₇ NH ₂ (2) Fatty acid oleic acid: C ₁₇ H ₃₃ COOH, stearic acid: C ₁₇ H ₃₅ COOH, palmitic acid: C ₁₅ H ₃₁ COOH, myristic acid: C ₁₃ H ₂₇ COOH, lauryl acid: C ₁₁ H ₂₃ COOH, capric acid: C ₉ H ₁₉ COOH, caprylic acid: C ₇ H ₁₅ COOH (3) mercaptan octadecyl sulfide Alcohol: C ₁₈ H ₃₇ SH, hexadecyl mercaptan: C ₁₆ H ₃₃ SH, tetradecyl mercaptan: C ₁₄ H ₂₉ SH, dodecyl mercaptan: C ₁₂ H ₂₅ SH, decane mercaptan: C ₁₀ H ₂₁ SH, octane mercaptan: C ₈ H ₁₇ SH (4) phosphine trioctyl phosphine: (C ₈ H ₁₇ ) ₃ P, triphenylphosphine: (C ₆ H ₅ ) ₃ P, tributyl Phosphine: (C ₄ H ₉ ) ₃ P (5) phosphine oxide trioctyl phosphine oxide: (C ₈ H ₁₇ ) ₃ P=O, triphenyl phosphine oxide: (C ₆ H ₅ ) ₃ P=O , Tributyl phosphine oxide: (C ₄ H ₉ ) ₃ P=O

In this embodiment, as shown in FIG. 3B, the quantum dot 10 may be a core-shell structure having a core 10a and a shell 10b covering the surface of the core 10a. As shown in FIG. 3B, it is preferable that many organic ligands 11 are coordinated on the surface of the quantum dot 10.

Furthermore, the outer shell 10b may be in a state of being solid-dissolved on the surface of the inner core 10a. The dotted line in FIG. 3B indicates the boundary between the core 10a and the shell 10b, which means that the boundary between the core 10a and the shell 10b can be confirmed or not confirmed by the analysis.

In this embodiment, the light L1 emitted from the light-emitting element 2 is a blue light mixed with visible light other than blue, which can reduce the red light-emitting quantum dots and the green light-emitting quantum dots contained in the wavelength conversion sheet 3 The content, so that the light emitting device 1 emits white light L2. In other words, even if the content of red light-emitting quantum dots and green light-emitting quantum dots contained in the wavelength conversion sheet 3 is reduced, the light L1 from the light-emitting element will be emitted as white light L2 through the wavelength conversion sheet 3 ((4) above) . In particular, if the light L1 emitted from the light-emitting element 2 is formed by mixing red light and green light with blue light, the red light-emitting quantum dots and green light-emitting quantum dots contained in the wavelength conversion sheet 3 can be more effectively reduced The content of points. As a result, the manufacturing cost of the wavelength conversion sheet 3 can be reduced. In addition, even if the quantum dots contain heavy metals such as Cd and other restricted objects, the amount of heavy metals in the restricted objects can be effectively controlled.

Furthermore, in addition to quantum dots, the wavelength conversion sheet 3 may also contain fluorescent pigments, fluorescent dyes, and the like. For example, it may be a mixture of YAG (Yttrium Aluminum Garnet, yttrium-aluminum-garnet) or Sialon and other phosphors.

The wavelength conversion sheet 3 of this embodiment is a sheet-like material in which quantum dots are dispersed by resin, and is not limited, for example, on both sides or one side of the wavelength conversion sheet 3, in other words, on the light incident side or light The exit side does not have the structure of the barrier layer. Furthermore, the wavelength conversion sheet 3 may be formed on at least one surface of a base film (not shown). Although the base film is not particularly limited, in terms of light transmittance, handleability (handling), and adhesion to the wavelength conversion sheet 3, PET (polyethylene terephthalate) is preferred. Ester) film. Or, PEN (polyethylene naphthalate) film can also be used instead of PET film or PE (polyethylene, polyethylene) film.

The wavelength conversion sheet 3 is formed in a thin plate shape, and the so-called "sheet" generally refers to a structure whose thickness is small relative to the length and width. Although the wavelength conversion sheet 3 does not matter whether it has flexibility or not, it preferably has flexibility. The wavelength conversion sheet 3 may be referred to simply as a sheet, or a film, a film sheet, or the like. Among them, in this specification, "film" is defined as a flexible sheet material. In addition, the wavelength conversion sheet 3 may be formed to have a fixed thickness, or may have a structure in which the thickness is deformed depending on the location, or gradually changes toward the length direction or the width direction, or changes stepwise.

The length dimension L, width dimension W, and thickness dimension T of the wavelength conversion sheet 3 are not limited, and various dimensions are changed according to different products. For example, it is used in the backlight of large products such as televisions, and also used in the backlight of small mobile devices such as smart phones. Therefore, matching products are required to determine the size.

In this embodiment, the resin used for the wavelength conversion sheet 3 is not particularly limited, and may include polypropylene, polyethylene, polystyrene, AS (Acrylonitrile-Styrene) resin, and ABS ( Acrylonitrile-Butadiene-Styrene, acrylonitrile-butadiene-styrene) resin, acrylic resin, methacrylic resin, polyvinyl chloride, polyacetal, polyamide, polycarbonate, modified polyphenylene ether, poly Butylene phthalate, polyethylene terephthalate, polyether, polyether sulfide, polyphenylene sulfide, polyamide imide, polymethylpentene, liquid crystal polymer, epoxy resin, phenol Based resins, urea resins, melamine resins, epoxy resins, diallyl phthalate resins, unsaturated polyester resins, polyimides, polyurethanes, silicone resins, styrene-based thermoplastic elastomers Body or a mixture of these several substances, etc.

In addition, in this embodiment, the wavelength conversion sheet 3 may contain a light scattering agent or a thickening agent. The light-scattering agent is not limited to the material, and can suggest _{fine particles such as SiO 2} , BN, and AlN. As an example, the wavelength conversion sheet 3 contains 1-10 wt% of a light scattering agent. In addition, the material of the thickener is not particularly limited, and examples include: carboxyvinyl polymer, carboxymethyl cellulose, methyl acrylate copolymer, bentonite (aluminum silicate) or lithium bentonite (magnesium silicate) series Additives and so on. By including the tackifier, the resin composition constituting the wavelength conversion sheet 3 can be adjusted to an appropriate viscosity, and the wavelength conversion sheet 3 can be easily formed into a specific thickness and a specific shape.

Moreover, in this embodiment, in order to improve the dispersibility of the quantum dots contained in the wavelength conversion sheet 3, it is preferable to include a dispersant. The material of the dispersant is not particularly limited. It can be used: epoxy resin, polyurethane, polycarboxylate, naphthalene sulfonate, formalin condensation polymer, polyethylene glycol , Partial alkyl ester compounds of polycarboxylic acid, polyether, polyalkylene polyamine, alkane sulfonate, quaternary ammonium salt, higher alcohol alkylene oxide, polyol ester, alkane Specific examples of dispersants based on polyamine-based or polyphosphate-based dispersants, etc., include DISPERBYK (registered trademark) manufactured by BYK-Chemie Japan.

In addition, the wavelength conversion sheet 3 shown in FIGS. 1 and 2 is formed in one piece, but for example, a plurality of wavelength conversion sheets 3 may be joined to form a specific size.

The plurality of light-emitting elements 2 shown in FIG. 2 are supported in a manner that can select whether to emit light, that is, not only can all the light-emitting elements 2 be used, but also, for example, only one light-emitting element 2 can be used. This kind of driving method is also called dimming, local dimming, area division method and so on.

Here, we will discuss, for example, the case where one light-emitting element 2 is turned on. When a blue LED is used as before, it is known that when the blue light is wavelength-converted by the wavelength conversion sheet 3, it will be affected by the diffuser 5 and the like. Diffusion, diffuse reflection, and uneven color or brightness (halo phenomenon).

In contrast to this, in this embodiment, even when not all the light-emitting elements 2 are turned on, for example, when one light-emitting element 2 is turned on, the light L1 emitted from the light-emitting element 2 can be adjusted to blue light. The light mixed with visible light other than blue (near white) can not only reduce the content of red light emitting quantum dots and green light emitting quantum dots contained in the wavelength conversion sheet 3, but also suppress color unevenness or uneven brightness (Halo phenomenon). In addition, color unevenness or brightness unevenness (halo phenomenon) can be suppressed without narrowing the color gamut too much.

<Second Embodiment> In the second embodiment, in order to suppress color unevenness or brightness unevenness (halo phenomenon), the wavelength conversion sheet 3 is coated or bonded to the surface of the partially reflective sheet.

4 and 5 are schematic cross-sectional views of the light-emitting device of this embodiment that are different from those in FIG. 1. In FIGS. 4 and 5, the same symbols as in FIG. 1 indicate the same members as in FIG. 1. As shown in FIG. 4, the wavelength conversion sheet 3 is disposed on the surface of the partially reflective sheet 11. The partially reflective sheet (partially reflective layer) 11 can use "BLT" manufactured by 3M Company.

The wavelength conversion sheet 3 can be coated on the surface of the partially reflective sheet 11 or can also be attached to the surface of the partially reflective sheet 11.

The light-emitting device 1 of the embodiment shown in FIG. 5 is different from FIG. 4 in that it is an edge type. That is, the LED (light source) is located beside the light guide plate 12, and the light passing through the light guide plate 12 from the light source is transmitted upward by the light guide plate 12. In the embodiment shown in FIG. 5, a partially reflective sheet 11 is provided on the light guide plate 12, and the wavelength conversion sheet 3 is provided on the surface of the partially reflective sheet 11.

The partially reflective sheet (partially reflective layer) 11 can transmit blue light and reflect red and green light. Or, the partially reflective sheet (partially reflective layer) 61 can reflect all the red light and the green light, and partially reflect the blue light.

For example, the issuing element (LED) 13 emits blue light. Therefore, part of the blue light passes through the partly reflective sheet 11, and the component 1 containing the sub-dots is wavelength-converted into red light and/or green light. The wavelength-converted red light and green light are emitted upwards instead of downwards by the partially reflective sheet 81.

Here, when a blue LED is used, in the structure of the non-partially reflective sheet 11, when the blue light is wavelength-converted by the component 1 containing sub-dots, there is color unevenness or brightness due to diffusion, diffuse reflection, etc. Uneven (halo phenomenon) conditions. In this regard, as in the present embodiment, by providing the partially reflective sheet 11, the halo phenomenon can be suppressed. Especially, as shown in FIG. 4, it is more effective when the number of LEDs in the direct-type optical element increases. In addition, by using the partially reflective sheet 11 to reduce the transmission of blue light, the amount of blue light to be reused can be increased, so that the brightness (luminous intensity) can be improved. Therefore, even if the quantum dots do not contain heavy metals that are restricted objects represented by Cd or Pb, high brightness can be obtained.

In addition, in the second embodiment shown in FIGS. 4 and 5, although the light L3 emitted from the light-emitting element 13 is blue light, it may be mixed with blue light as in the first embodiment shown in FIG. 1 There is light from visible light other than blue. For example, the light L3 may be light (near white light) formed by mixing blue light with red light and green light whose luminous intensity is weaker than that of blue light. [Example]

Hereinafter, the effects of the present invention will be described by the examples and comparative examples of the present invention. In addition, the present invention is not limited in any way by the following examples.

＜Brightness experiment with or without partial reflection sheet＞ The following samples were used in the experiment. (Sample 1) Straight down BL (blue light) + QD sheet + 稜鏡 (Sample 2) Directly down BL (blue light) + BLT sheet coated with QD + 稜鏡 (Sample 3) Straight down BL (blue light) + BLT sheet + QD sheet + 稜鏡 (Sample 4) Straight down BL (blue light) + QD sheet + 稜鏡 + DBEF (Sample 5) Directly down BL (blue light) + BLT sheet coated with QD + 稜鏡 + DBEF (Sample 6) Straight down BL (blue light) + BLT sheet + QD sheet + 稜鏡 + DBEF

Furthermore, the BLT sheet is a partially reflective sheet manufactured by 3M Company. The QD sheet contains quantum dots that emit red light and green light. The QD coated BLT sheet is coated on the surface of the BLT sheet with QD liquid containing quantum dots emitting red light and green light to form a QD layer. DBEF is a reflective polarizing film manufactured by 3M Company.

In the experiment, the groups were divided into two groups, sample 1 to sample 3, and sample 4 to sample 6, to measure the relationship between wavelength and brightness (luminous intensity). The measurement of the luminous intensity uses a spectrofluorimeter (FP-8500 manufactured by JASCO Corporation).

Fig. 6 is a graph showing the relationship between the wavelength of 400 nm to 700 nm and the luminous intensity in sample 1 to sample 3. Fig. 7 is a graph showing the relationship between the wavelength of 400 nm to 700 nm and the luminous intensity in sample 4 to sample 6. Fig. 8 is a graph showing the relationship between the wavelengths of 500 nm to 700 nm and the luminous intensity in sample 1 to sample 3. Fig. 9 is a graph showing the relationship between the wavelength of 500 nm to 700 nm and the luminous intensity in sample 4 to sample 6. Furthermore, in FIGS. 8 and 9, compared with FIGS. 6 and 7, the range of the luminous intensity on the vertical axis is enlarged.

As shown in Fig. 6 and Fig. 7, in Sample 1 and Sample 4 without a partial reflection sheet, the blue luminous intensity becomes higher. In contrast, in the samples 2, 3, 5, and 6 having a partially reflective sheet, the blue luminous intensity was controlled.

In addition, as shown in Figs. 8 and 9, in the samples 1 and 4 without the partially reflective sheet, the red luminous intensity and the green luminous intensity are reduced. Compared with this, the sample 2 with the partially reflective sheet In 3, 5 and 6, the red luminous intensity and green luminous intensity have been improved.

(Sample 7) Edge BL (blue light) + QD sheet + 稜鏡 (Sample 8) Edge BL (blue light) + BLT sheet coated with QD + 稜鏡 (Sample 9) Edge BL (blue light) + BLT sheet + QD sheet + 稜鏡 (Sample 10) Edge BL (blue light) + QD sheet + 稜鏡 + DBEF (Sample 11) Directly down BL (blue light) + BLT sheet coated with QD + 稜鏡 + DBEF (Sample 12)

Edge BL (blue light) + BLT sheet + QD sheet + 稜鏡 + DBEF Samples 7 to 12 are experimental examples in which edge BL is used instead of the direct lower BL of samples 1 to 6. That is, samples 1 to 6 have the straight-down type structure shown in FIG. 4, and samples 7 to 12 have the edge type structure shown in FIG.

Fig. 10 is a graph showing the relationship between the wavelengths of 400 nm to 700 nm and the luminous intensity in samples 7 to 9. FIG. 11 is a graph showing the relationship between the wavelength of 400 nm to 700 nm and the luminous intensity in sample 10 to sample 12. Fig. 12 is a graph showing the relationship between the wavelengths of 500 nm to 700 nm and the luminous intensity in samples 7 to 9. FIG. 13 is a graph showing the relationship between the wavelengths of 500 nm to 700 nm and the luminous intensity in sample 10 to sample 12. Furthermore, in FIGS. 12 and 13, compared to FIGS. 10 and 11, the range of the luminous intensity on the vertical axis is enlarged.

As shown in Fig. 10 and Fig. 12, the blue luminous intensity of samples 7 and 10 without partially reflective sheeting becomes higher. Compared with this, samples 8, 9, 11, and 10 with partially reflective sheeting In 12, the blue luminous intensity is controlled.

In addition, as shown in Figs. 12 and 13, in the samples 7 and 10 without a partially reflective sheet, the red luminous intensity and the green luminous intensity are reduced. Compared with this, the sample 8 with a partially reflective sheet In 9, 11, and 12, the red luminous intensity and green luminous intensity have been improved.

As mentioned above, it can be seen that by using a partially reflective sheet, the blue luminous intensity can be controlled, and the red luminous intensity and the green luminous intensity can be increased. The wavelength of the light from the blue LED can be converted to increase the brightness of the white light emitted. , And can suppress uneven brightness.

Furthermore, there is not much difference in luminous intensity in the case of applying QD on the surface of the BLT sheet and the case of overlapping the QD sheet on the BLT sheet. [Industrial availability]

According to the present invention, a light-emitting device can be provided, which can reduce the content of red light-emitting quantum dots and green light-emitting quantum dots contained in the wavelength conversion sheet, reduce the manufacturing cost of the wavelength conversion sheet, and suppress the halo phenomenon. Glows white light. The light-emitting device can be used as a backlight device of a display device, for example.

This application is based on Japanese Patent Application No. 2019-188398 filed on October 15, 2019. Its entire content is included in this article.

1: Light-emitting device 2: Light-emitting element 3: Wavelength conversion sheet 4: substrate 5: diffuser 6, 7: Optical sheet 10: Quantum dots 10a: Kernel 10b: shell 11: Organic ligand 12: Light guide plate 13: Light-emitting element L: Length of wavelength conversion sheet 3 L L1: Light emitted from light-emitting element 2 L2: white light L3: Light emitted from light-emitting element 13 T: The thickness of the wavelength conversion sheet 3 W: The width of the wavelength conversion sheet 3

FIG. 1 is a schematic cross-sectional view of the light-emitting device of this embodiment. FIG. 2 is a schematic plan view of the light-emitting device of this embodiment. FIG. 3A is a schematic diagram of the quantum dot of this embodiment. FIG. 3B is a schematic diagram of the quantum dot of this embodiment. FIG. 4 is a schematic cross-sectional view of the light-emitting device of this embodiment that is different from FIG. 1. FIG. 5 is a schematic cross-sectional view of the light-emitting device of this embodiment that is different from FIG. 1. Figure 6 is a graph showing the relationship between wavelength (400 nm ~ 700 nm) and brightness. This graph uses a direct-type optical element with the content of the partially reflective sheet and the content of the non-reflective sheet. The result of the point-of-point direct-type optical element. Figure 7 is a graph showing the relationship between wavelength (400 nm ~ 700 nm) and brightness. This graph uses a direct type optical element with a content of sub-points of a partially reflective sheet (with DBEF (Dual Brightness Enhancement Film, reflective type) Polarizing film)), and the result of a direct-type optical element (with DBEF) that does not have the content of sub-points of a partially reflective sheet. Figure 8 is a graph showing the relationship between wavelength (500 nm ~ 700 nm) and brightness. This graph uses a direct-type optical element with the content of the partially reflective sheet and the content of the non-reflective sheet. The result of the point-of-point direct-type optical element. Figure 9 is a graph showing the relationship between wavelength (500 nm to 700 nm) and brightness. This graph uses a direct-type optical element (with DBEF) that has a partially reflective sheet and does not have a partially reflective sheet. The result of the direct-type optical element (with DBEF) with the content of the sub-point of the material. Figure 10 is a graph showing the relationship between wavelength (400 nm ~ 700 nm) and brightness. This graph uses edge-type optical elements with the content of the partially reflective sheet and the content of the non-reflective sheet. The result of point-of-edge optics. Figure 11 is a graph showing the relationship between wavelength (400 nm to 700 nm) and brightness. This graph uses an edge-type optical element (with DBEF) with the content of sub-points of a partially reflective sheet and does not have a partially reflective sheet The result of the edge-type optical element (with DBEF) with the content of the sub-point of the material. Figure 12 is a graph showing the relationship between wavelength (500 nm ~ 700 nm) and brightness. This graph uses edge-type optical elements with a partially reflective sheet's content sub-points, and does not have a partially reflective sheet's content sub-points The result of edge optics. Figure 13 is a graph showing the relationship between wavelength (500 nm to 700 nm) and brightness. This graph uses an edge-type optical element (with DBEF) with the content of sub-points of a partially reflective sheet and does not have a partially reflective sheet The result of the edge-type optical element (with DBEF) with the content of the sub-point of the material.

1: Light-emitting device

2: Light-emitting element

3: Wavelength conversion sheet

4: substrate

5: diffuser

6, 7: Optical sheet

L1: Light emitted from light-emitting element 2

L2: white light

T: The thickness of the wavelength conversion sheet 3

Claims (6)

A light emitting device, characterized in that it is provided with a light emitting element and a wavelength conversion member arranged on the light emitting side of the light emitting element, and The above-mentioned light-emitting element can be adjusted to produce blue light mixed with visible light other than blue, The wavelength conversion member includes red fluorescent particles and green fluorescent particles, The light from the light-emitting element emits white light through the wavelength conversion member. The light-emitting device according to claim 1, wherein the light-emitting element is adjusted to be capable of coloring the blue light, and the blue light is mixed with red light and green light whose luminous intensity is weaker than that of the blue light. The light-emitting device of claim 1 or 2, wherein the wavelength conversion member is sheet-shaped. The light-emitting device according to any one of claims 1 to 3, wherein a plurality of the light-emitting elements are arranged in a matrix in such a way that the light-emitting elements to be made to emit light can be selected, The colored light from one or more of the light-emitting elements emits white light from the surface of the wavelength conversion member through the wavelength conversion member. The light-emitting device according to any one of claims 1 to 4, wherein the wavelength conversion member is coated or attached to the surface of the partially reflective sheet. A light emitting device, characterized in that it is provided with a light emitting element and a wavelength conversion member arranged on the light emitting side of the light emitting element, and The wavelength conversion member includes red fluorescent particles and green fluorescent particles, The above-mentioned wavelength conversion member is coated or attached to the surface of the partially reflective sheet, The light from the light-emitting element emits white light through the wavelength conversion member.

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