Patent Description:
A quantum dot is a nanoparticle composed of several hundreds to several thousands of semiconductor atoms, having a particle diameter on the order of several nm to several tens of nm, and forms a quantum well structure. The quantum dot is also called a "nanocrystal.

A peak light emission wavelength of the quantum dot can be changed in various ways according to the particle diameter or a composition of crystal, and, for example, Patent Literature <NUM> describes a wavelength conversion layer containing quantum dots formed on a light-guiding board by directly applying it.

<CIT> discloses thermoplastic resin formulations for use as a light transmitting layer (e.g., encapsulant layer) in a photovoltaic module comprising: (a) a light transmitting thermoplastic resin, (b) at least one down conversion material that exhibits a maximum in incident radiation absorption in the range of <NUM> to <NUM> and a maximum in radiation emission at a relatively longer wavelength in the range of <NUM> to <NUM> and improves the efficiency of photovoltaic electric current generation in a photovoltaic module; and (c) a light stabilizer additive that transmits at least about <NUM> percent of the ultraviolet (UV) electromagnetic radiation having a wavelength in the range of from about <NUM> to about <NUM>. Also disclosed are sheet materials prepared from such resins and photovoltaic modules incorporating such sheet materials.

<CIT> discloses a molded nanoparticle phosphor for light emitting applications fabricated by converting a suspension of nanoparticles in a matrix material precursor into a molded nanoparticle phosphor. The matrix material can be any material in which the nanoparticles are dispersible, and which is moldable. The molded nanoparticle phosphor can be formed from the matrix material precursor/nanoparticle suspension using any molding technique, such as polymerization molding, contact molding, extrusion molding, injection molding, for example. Once molded, the molded nanoparticle phosphor can be coated with a gas barrier material, for example, a polymer, metal oxide, metal nitride or a glass. The barrier-coated molded nanoparticle phosphor can be utilized in a light- emitting device, such as an LED. For example, the phosphor can be incorporated into the packaging of a standard solid-state LED and used to down-convert a portion of the emission of the solid-state LED emitter.

<CIT> discloses a composition that contains a quantum dot fluorescent body and that is able to suppress quenching of the quantum dot fluorescent body, a molded body of a quantum dot fluorescent body dispersion resin, a structure containing a quantum dot fluorescent body, a light-emitting device, an electronic apparatus, or a mechanical device, and a method for producing the molded body of a quantum dot fluorescent body dispersion resin. A quantum dot fluorescent body is dispersed in a cycloolefin (co)polymer that is a dispersion resin to form the composition containing a quantum dot fluorescent body, and the composition containing a quantum dot fluorescent body is molded, forming the molded body of the quantum dot fluorescent body dispersion resin, and a gas barrier layer that reduces the passage of oxygen to the molded body of the quantum dot dispersion resin is formed at a portion or the entirety of the surface of the molded body of the quantum dot fluorescent body dispersion resin, and furthermore, a light-emitting device is configured using the composition containing the quantum dot fluorescent body as a sealing material that seals an LED chip.

<CIT> discloses a curable resin composition including as necessary components: (A) an organic compound having at least two carbon-carbon double bonds, reactive with a SiH group, in a molecule; (B) a compound containing at least two SiH groups in a molecule; (C) a hydrosilylation catalyst; (D) a white pigment; (E) an inorganic filler; (F) a silicone compound having at least one carbon-carbon double bonds, reactive with a SiH group, in a molecule; and (G) nano particles having an average particle diameter of <NUM>-<NUM>. At least one component among (A), (B) and (F) is a liquid at <NUM>, and the heat curable resin composition is a solid at <NUM>.

Thus, conventionally, layers containing quantum dots are applied or potted onto a surface requiring wavelength conversion. This prevents layers containing quantum dots from being formed into a free shape, resulting in poor practicality.

Furthermore, Patent Literature <NUM> has no description about means for dispersing quantum dots in resin.

In addition, it is necessary to enhance durability against environmental changes of quantum dots and improve reliability, but prior arts do not mention the durability and have established neither internal configuration of resin nor manufacturing method thereof in order to improve the reliability.

The present invention has been implemented in view of the above-described problems and it is an object of the present invention to provide a method of manufacturing a resin molded product which can increase the degree of freedom of shape, enhance durability against environmental changes and improve reliability, a manufacturing method thereof, and a wavelength conversion member and an illumination member. Solution to Problem.

The present invention is defined by the independent claim. Further embodiments of the present invention are described in the dependent claims.

According to the method of manufacturing a resin molded product according to the present invention, it is possible to enhance the degree of freedom of shape. It is further possible to increase dispersibility of quantum dots, easily maintain a light emission characteristic for a long period of time and improve durability against environmental changes.

Furthermore, according to the present invention, it is possible to form a wavelength conversion member and an illumination member with excellent reliability using the resin molded product containing quantum dots.

A resin molded product according to the present embodiment is configured by molding resin on which many quantum dots are dispersed.

The quantum dots of the present embodiment can each include a core of semiconductor particles and a shell that coats the perimeter of the core. For example, CdSe is used for the core, but the material thereof is not particularly limited. For example, a core material containing at least Zn and Cd, a core material containing Zn, Cd, Se and S, or a composite of some of ZnCuInS, CdS, CdSe, ZnS, ZnSe, InP and CdTe can be used.

The shell protects the core as a fluorescence section. Quantum efficiency improves by removing surface defects or dangling bond of the core. As an example, a bandgap of the shell is greater than a bandgap of the core, but the bandgap is not limited to this.

The shell may have a so-called multi-shell structure including a first shell (shell I) that coats the surface of the core and a second shell (shell II) that coats the surface of the first shell. In this case, for example, the bandgap of the second shell is greater than the bandgap of the first shell, but the bandgap is not limited to this.

The quantum dots according to the present embodiment may be composed of only cores without any shells being formed. That is, the quantum dots may not be provided with any coating structure with shells as long as the quantum dots are provided with at least cores. For example, when the cores are coated with shells, a region having a coating structure may be small or a coating portion may be too thin to analyze or check the coating structure. Therefore, it is possible to determine quantum dots by an analysis regardless of the presence/absence of the shells.

In the present embodiment, metal soap is preferably included as a dispersant to appropriately disperse many quantum dots in the resin of the resin molded product. Thus, it is possible to effectively enhance the dispersibility in the resin of quantum dots in the resin molded product.

The metal soap is made of minute particles, exhibits excellent dispesibility with respect to quantum dots which are inorganic substances and adds sufficient smoothness to resin.

Fatty acid such as stearic acid, oleic acid, ricinoleic acid, octylic acid, lauric acid or metal such as lithium, magnesium, calcium, barium, zinc is used for the metal soap. Among them, the metal soap is preferably calcium stearate.

In the present embodiment, the metal soap contained in resin preferably falls within a range of <NUM> ppm to <NUM>, <NUM> ppm by weight with respect to the resin. This makes it possible to increase dispersibility or smoothness and also prevents turbidity or surface irregularity or the like on the resin surface. The weight ratio of the metal soap to the quantum dots contained is <NUM>/<NUM> to <NUM>. The quantum dots are suitably on the order of <NUM> ppm to <NUM>, <NUM> ppm by weight with respect to the resin. Therefore, the metal soap is suitably <NUM> ppm to <NUM>,<NUM> ppm by weight with respect to the resin.

Thus, the Applicant has discovered that when the metal soap (especially, calcium stearate) is introduced, the metal soap wraps the quantum dots and thereby improves dispersibility.

Furthermore, in the present embodiment, the resin preferably contains elastomer. For example, when polypropylene (PP) is selected as resin, transparency can be improved by mixing elastomer. In this case, elastomer highly compatible with polypropylene resin is preferable.

In the present embodiment, the resin preferably contains a scattering agent. Addition of the scattering agent can improve a light emission characteristic. Minute particles such as silica (SiO<NUM>), BN, AlN can be presented as the scattering agent.

The resin molded product according to the present embodiment may be configured so as to include a resin layer in which quantum dots are contained in the resin and a coating layer that coats the surface of the resin. Glass coating, epoxy coating, diamond -like carbon (DLC) or the like can be presented as the coating layer. This makes it possible to improve durability with respect to water content in the atmosphere and thereby provide high reliability.

Although the resin constituting the resin molded product is not particularly limited, it is possible to use polypropylene, polyethylene, polystyrene, AS resin, ABS resin, methacryl resin, polyvinyl chloride, polyacetal, polyamide, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polysulfone, polyethersulphone, polyphenylene sulfide, polyamide imide, polymethyl pentene, liquid crystal polymer, epoxy resin, phenol resin, urea resin, melamine resin, epoxy resin, diallyl phthalate resin, unsaturated polyester resin, polyimide, polyurethane, silicone resin, or a mixture of some of these substances.

The resin molded product according to the present embodiment may include quantum dots fluorescent pigments other than quantum dots and fluorescent substances as fluorescent dye. Examples of such materials include, a red light emission quantum dot that emits red light when irradiated with blue light and a green light emission fluorescent substance that emits green light or a red light emission quantum dot that emits green light and a red light emission fluorescent substance that emits red light. White light can be obtained by irradiating such a resin molded product with blue light. Examples of the fluorescent substance include YAG (yttrium aluminum garnet) base, TAG (terbium aluminum garnet) base, sialon base, BOS (barium orthosilicate) base, but the material is not particularly limited.

A dispersion state of quantum dots of the present embodiment refers to a dispersion state in which quantum dots are singly dispersed in resin, a dispersion state in which a plurality of quantum dots form an aggregate and such aggregates are dispersed in resin or single quantum dots and an aggregate of quantum dots are dispersed respectively in resin.

Not more than several hundreds of aggregates are contained in resin within a square of <NUM>. To be more specific, on the order of <NUM> to <NUM> aggregates are preferably contained. Regarding the scale of each aggregate, the length in the longitudinal direction is <NUM> or less and preferably <NUM> or less. Furthermore, the aggregate is preferably composed of not more than several hundreds of aggregated quantum dots. To be more specific, the aggregate is preferably composed of on the order of <NUM> to <NUM> quantum dots. In this way, according to the present embodiment, quantum dots form each aggregate and these aggregates are appropriately dispersed in resin.

The following applications can be provided using the resin molded product according to the present embodiment. <FIG> illustrate application examples using the resin molded product according to the present embodiment.

In <FIG>, a wavelength conversion bar (fluorescence bar) <NUM> is interposed between light-emitting devices <NUM> such as LEDs and a light-guiding board <NUM>. The wavelength conversion bar <NUM> shown in <FIG> is configured by molding quantum-dot-containing resin of the present embodiment into a bar shape, rod shape or stick shape. Light emitted from the light-emitting device <NUM> is wavelength-converted by the wavelength conversion bar <NUM>, and the wavelength-converted light is emitted to the light-guiding board <NUM>. For example, the wavelength conversion bar <NUM> includes quantum dots having a fluorescence wavelength of <NUM> (green color) and <NUM> (red color). For example, part of blue photons emitted from the light-emitting device <NUM> is converted to green color or red color by the quantum dots and white light is thereby emitted from the wavelength conversion bar <NUM> toward the light-guiding board <NUM>.

<FIG> shows a wavelength conversion sheet <NUM> which is formed using the quantum-dot-containing resin of the present embodiment provided on a light emission surface of the light-guiding board <NUM>. According to the present embodiment, the wavelength conversion sheet <NUM> is formed into a sheet-like shape in advance, instead of applying and forming it on the light-guiding board <NUM>. The wavelength conversion sheet <NUM> is superimposed on the light emission surface of the light-guiding board <NUM>. Another film such as a diffusion film may be interposed between the light-guiding board <NUM> and the wavelength conversion sheet <NUM>.

The light-guiding board <NUM> itself may be molded using the quantum-dot-containing resin of the present embodiment. In this case, it does not matter whether or not the wavelength conversion sheet <NUM> is present. Both the light-guiding board <NUM> and the wavelength conversion sheet <NUM> may also include quantum dots that emit green light and quantum dots that emit red light. Furthermore, the light-guiding board <NUM> may also include quantum dots that emit green light and the wavelength conversion sheet <NUM> may include quantum dots that emit red light. Conversely, the light-guiding board <NUM> may include quantum dots that emit red light and the wavelength conversion sheet <NUM> may include quantum dots that emit green light.

Note that the fluorescence member using the resin molded product of the present embodiment can conduct wavelength conversion, and therefore, it can be said to be a wavelength conversion member, and both are not clearly distinguishable.

In <FIG>, for example, an illumination cover <NUM> of an illumination device <NUM> can be molded using the quantum-dot-containing resin of the present embodiment. Here, "illumination" refers to a state in which lighting is provided indoors or outdoors. In the present embodiment, the resin molded product can be molded into, for example, an electric bulb shape as shown in <FIG> or a surface emitting type illumination cover shape. It is possible to obtain a white illumination device <NUM> using a blue light-emitting LED as a light-emitting device of the illumination device <NUM>, and using an illumination cover <NUM> including both quantum dots that convert blue light to red light and quantum dots that convert blue light to green light. Illumination of desired color can be obtained by adjusting the amount of quantum dots and ratio.

As a mode of the illumination device, the structure shown in <FIG> may be used to perform surface emission. In this case, the plane shape of the light-guiding board <NUM> and the wavelength conversion sheet <NUM> when seen from above may be rectangular or square, but without being limited to this, any free shape such as circular, triangular, hexagonal can be adopted. A curved surface as shown in <FIG> or a flat surface may be used and the surface shape is not limited. The illumination device may also be a fiber shape.

Furthermore, a structure may also be adopted in which the space between the light-emitting device of the illumination device and the illumination surface (light emission surface) is filled with quantum-dot-containing resin. That is, it is possible to create an illumination of a free shape.

<FIG> illustrates a light source unit <NUM> with a plurality of light-emitting devices <NUM> such as LEDs installed on a base material <NUM>. A dome-shaped lens part <NUM> covers each light-emitting device <NUM> as shown in <FIG>. The dome-shaped lens part <NUM> has, for example, a semispherical shape, an inside of which is hollow. The space between the base material <NUM>, the light-emitting device <NUM>, and the surface inside the lens part <NUM> may be hollow or may be filled with an appropriate resin material. The lens part <NUM> may be molded using the quantum-dot-containing resin according to the present embodiment. For example, by applying a transparent adhesive or the like to a part where the lens part <NUM> is in contact with the base material <NUM> to a predetermined thickness, it is possible to simply paste the lens part <NUM> to the top surface of the base material <NUM> by covering each light-emitting device <NUM>. A white light source unit <NUM> is obtained using a blue light-emitting LED as the light-emitting device <NUM> and using the lens part <NUM> including quantum dots that convert blue light to red light and quantum dots that convert blue light to green light.

<FIG> are different from <FIG> in the shapes of lens parts <NUM> and <NUM>. The lens part <NUM> shown in <FIG> has a shape in which the top surface central part of the dome-shaped lens part shown in <FIG> is dented downward, whereas the lens part <NUM> shown in <FIG> has a cylindrical side face and has a shape, a top central part having a rectangular cross section is dented downward. It is thereby possible to change a radiation angle range of light and radiation direction from those of the light source unit <NUM> shown in <FIG>.

In <FIG>, the structure may be such that the interior of each lens is filled with the quantum-dot-containing resin according to the present embodiment. Alternatively, a part of quantum-dot-containing resin in which the light-emitting device <NUM> is disposed may be dented and a surface of which is molded into the lens surface shown in <FIG>. For example, the lens parts <NUM>, <NUM> or <NUM> may be formed directly by injection molding on the base material <NUM> on which the light-emitting device <NUM> is mounted.

<FIG> illustrates a light diffusion apparatus <NUM> provided with a light emission sheet <NUM> and a diffusion board <NUM>. The light emission sheet <NUM> is provided with a plurality of light sources 15a and each light source 15a is composed of a light-emitting device such as an LED and a resin layer that covers the surface side of each light-emitting device. The light emission sheet <NUM> shown in <FIG> has a structure in which each light source 15a is molded on a support body <NUM>. The resin layer that covers each light-emitting device of each light source 15a can be formed of quantum-dot-containing resin. For example, the light emission sheet <NUM> is the light source unit <NUM> shown in <FIG>.

The light diffusion apparatus <NUM> shown in <FIG> constitutes a backlight or the like disposed on the rear side corresponding to a display section such as a liquid crystal display. Furthermore, the light diffusion apparatus <NUM> shown in <FIG> can also be used as an illumination.

In <FIG>, the diffusion board <NUM> may be formed of a molded product of quantum-dot-containing resin. In this case, quantum dots may or may not be contained in the resin layer that covers a light-emitting device such as an LED in each light source 15a provided on the light emission sheet <NUM>. Both the resin layer of each light source 15a and the diffusion board <NUM> may also include quantum dots that emit green light and quantum dots that emit red light. Furthermore, the resin layer of each light source 15a may include quantum dots that emit green light and the diffusion board <NUM> may include quantum dots that emit red light. Conversely, the resin layer of each light source 15a may include quantum dots that emit red light and the diffusion board <NUM> may include quantum dots that emit green light.

<FIG> illustrate light source apparatuses <NUM> and <NUM>. As shown in <FIG>, the light source apparatus <NUM> is composed of an array of light sources <NUM> each provided with a plurality of LEDs on a base material <NUM>, and reflectors <NUM> disposed between the respective light sources <NUM>. Each light source <NUM> may include a light-emitting device such as an LED. The reflector <NUM> is formed of the quantum-dot-containing resin according to the present embodiment. For example, the quantum-dot-containing resin of the present embodiment can be molded and processed into the reflector <NUM>.

The light source apparatus <NUM> in <FIG> is, for example, a backlight, and a display section such as a diffusion board and a liquid crystal display (not shown) is provided above the light source apparatus <NUM>.

The light source apparatus <NUM> has a structure in which the reflector <NUM> is arranged around each light source <NUM>, light returning to the light source apparatus <NUM> side is reflected by the reflector <NUM>, allowing the entire surface of the light source apparatus <NUM> to emit uniform light toward the display section.

In the light source apparatus <NUM> shown in <FIG>, a side wall <NUM> is provided between neighboring light sources <NUM>. The side walls <NUM> are formed into, for example, a grid shape and the light source <NUM> and the reflector <NUM> are arranged in each grid-shaped space. Providing the side wall <NUM> for partitioning each light source <NUM> can improve reflection efficiency and optical wavelength conversion efficiency. As shown in <FIG>, the side wall <NUM> may be molded integrally with the base material <NUM> or may be molded separately. Alternatively, the reflector <NUM> and the side wall <NUM> may be integrated into one unit. For example, quantum-dot-containing resin of the present embodiment can be molded and processed into the reflector <NUM> and the side wall <NUM>.

<FIG> is a schematic view of an application using a sheet member provided with quantum dots of the present embodiment. A sheet member <NUM> including quantum dots can be assembled into, for example, a backlight apparatus <NUM> shown in <FIG>. In <FIG>, the backlight apparatus <NUM> is composed of a plurality of light-emitting devices <NUM> (LEDs) and the sheet member <NUM> disposed opposite to light-emitting devices <NUM>. As shown in <FIG>, each light-emitting device <NUM> is supported by a surface of a support body <NUM>. In <FIG>, the backlight apparatus <NUM> is arranged on the back side of a display section <NUM> such as a liquid crystal display to constitute a display apparatus <NUM>. Note that the light-emitting device <NUM> shown in <FIG> may be the light source unit <NUM> shown in <FIG>.

Note that although not shown in <FIG>, a diffusion board for diffusing light and another sheet or the like may be interposed between the light-emitting device <NUM> and the display section <NUM> in addition to the sheet member <NUM>.

Although the sheet member <NUM> is formed as a single sheet, a plurality of sheet members <NUM> may be connected together so as to have a predetermined size. The configuration in which the plurality of sheet members <NUM> connected together through tiling will be referred to as a "composite sheet member" hereinafter.

In <FIG>, the light-emitting device <NUM>, a composite sheet member <NUM>, a diffusion board <NUM> and the display section <NUM> are arranged in that order. Even when unevenness of a light emission color occurs due to deterioration of quantum dots caused by irregular reflection or vapor permeating from a joint between sheet members constituting the composite sheet member <NUM>, it is possible to appropriately suppress the occurrence of unevenness in color on a display of the display section <NUM>. That is, since the light emitted from the composite sheet member <NUM> is diffused by the diffusion board <NUM> and then enters the display section <NUM>, it is possible to suppress unevenness in color on the display of the display section <NUM>.

<FIG> is a perspective view and a cross-sectional view along a line A-A of the wavelength conversion apparatus provided with quantum dots according to the present embodiment. <FIG> is a perspective view of the wavelength conversion apparatus and <FIG> is a cross-sectional view of the wavelength conversion apparatus shown in <FIG> cut in a surface direction along the line A-A and seen from a direction indicated by arrows.

As shown in <FIG>, a wavelength conversion apparatus <NUM> is composed of a container <NUM> and a molded body <NUM> containing a wavelength conversion substance.

The container <NUM> is provided with a storage space <NUM> that can accommodate and store the molded body <NUM> including a wavelength conversion substance. The container <NUM> is preferably a transparent member. The term "transparent" refers to what is generally recognized as being transparent or what has a visible light transmittance of approximately <NUM>% or more.

The longitudinal and lateral sizes of the container <NUM> are on the order of several mm to several tens of mm, and the longitudinal and lateral sizes of the storage space <NUM> are on the order of several hundreds of µm to several mm.

As shown in <FIG>, the container <NUM> is provided with a light incident surface 71a, a light emission surface 71b and a side face 71c that connects the light incident surface 71a and the light emission surface 71b. As shown in <FIG>, the light incident surface 71a and the light emission surface 71b are located opposite to each other.

As shown in <FIG>, the storage space <NUM> is formed in the container <NUM> inside the light incident surface 71a, the light emission surface 71b and the side face 71c. Note that part of the storage space <NUM> may reach the light incident surface 71a, the light emission surface 71b or the side face 71c.

The container <NUM> shown in <FIG> is, for example, a glass tube container such as a glass capillary. However, the container <NUM> may be made of resin or the like if it can constitute the above-described container with excellent transparency.

As shown in <FIG>, the molded body <NUM> containing the wavelength conversion substance is disposed in the storage space <NUM>. As shown in <FIG>, the storage space <NUM> has an opening from which the molded body <NUM> containing the wavelength conversion substance can be inserted.

The molded body <NUM> containing the wavelength conversion substance can be inserted into the storage space <NUM> by means such as pressure fitting or adhesion. When the molded body <NUM> is press-fitted, by molding the molded body <NUM> containing the wavelength conversion substance in completely the same size as the storage space <NUM> or in a size slightly greater than the storage space <NUM> and inserting the molded body <NUM> containing the wavelength conversion substance into the storage space <NUM> while adding a pressure, it is possible to prevent a gap from being produced not only in the molded body <NUM> containing the wavelength conversion substance but also between the molded body <NUM> containing the wavelength conversion substance and the container <NUM>.

Furthermore, when the molded body <NUM> containing the wavelength conversion substance is adhered and fixed to the storage space <NUM>, the molded body <NUM> containing the wavelength conversion substance is molded so as to be smaller than the storage space <NUM>, and with an adhesion layer applied to the side face of the molded body <NUM> containing the wavelength conversion substance, the molded body <NUM> containing the wavelength conversion substance is inserted into the storage space <NUM>. In this case, the cross-sectional area of the molded body <NUM> may be slightly smaller than the cross-sectional area of the storage space <NUM>. In this way, the molded body <NUM> containing the wavelength conversion substance and the container <NUM> come into close contact with each other via the adhesion layer, making it possible to prevent a gap from being formed between the molded body <NUM> containing the wavelength conversion substance and the container <NUM>. For the adhesion layer, the same resin as the molded body <NUM> or resin having a common basic structure can be used. Alternatively, a transparent adhesive member may also be used as the adhesion layer.

Furthermore, a refractive index of the molded body <NUM> containing the wavelength conversion substance may be preferably smaller than a refractive index of the container <NUM>. Thus, part of light incident on the molded body <NUM> containing the wavelength conversion substance is totally reflected by the side wall portion of the container <NUM> facing the storage space <NUM>. This is because an angle of incidence on the medium side which has a smaller refractive index is greater than an angle of incidence on the medium side which has a greater refractive index. This makes it possible to reduce the amount of light leaking from the side of the container <NUM> toward the outside, thus improving color conversion efficiency and light emission intensity.

A light-emitting device is disposed on the light incident surface 71a side of the wavelength conversion apparatus <NUM> shown in <FIG>. Furthermore, the light-guiding board <NUM> or the like shown in <FIG> is disposed on the light emission surface 71b side of the wavelength conversion apparatus <NUM>. Note that in <FIG>, the molded body <NUM> is used, but a resin composition containing quantum dots may be injected to form a quantum dot layer.

<FIG> is a perspective view of the light-emitting apparatus composed of the wavelength conversion member provided with the quantum dots according to the present embodiment. <FIG> is a cross-sectional view of the light-emitting device shown in <FIG> in which the respective members are assembled, cut along a line B-B in a height direction and seen from a direction indicated by arrows.

The light-emitting device <NUM> shown in <FIG> and <FIG> is composed of a wavelength conversion member <NUM> and an LED chip (light emission section) <NUM>. The wavelength conversion member <NUM> is provided with a container <NUM> composed of a plurality of pieces such as a container body <NUM> and a lid <NUM>. Furthermore, as shown in <FIG>, a bottomed storage space <NUM> is formed in the center of the container body <NUM>. A wavelength conversion layer <NUM> containing quantum dots is provided in the storage space <NUM>. The wavelength conversion layer <NUM> may be a molded body or may fill the inside of the storage space <NUM> through potting processing or the like. The container body <NUM> and the lid <NUM> are joined together via an adhesion layer.

An undersurface of the container <NUM> of the wavelength conversion member <NUM> shown in <FIG> and <FIG> is a light incident surface 79a. A top surface facing the light incident surface 79a is a light emission surface 79b. The storage space <NUM> is formed at a position inside each side face 79c provided in the container <NUM> of the wavelength conversion member <NUM> shown in <FIG> and <FIG>.

As shown in <FIG>, the LED chip <NUM> is connected to a print wiring substrate <NUM> and the LED chip <NUM> is surrounded by a frame body <NUM> as shown in <FIG> and <FIG>. The inside of the frame body <NUM> is sealed with a resin layer <NUM>.

As shown in <FIG>, the wavelength conversion member <NUM> is joined to the top surface of the frame body <NUM> via an adhesion layer (not shown) to constitute a light-emitting device <NUM> such as an LED.

It is thereby possible to freely mold the quantum-dot-containing resin according to the present embodiment into various shapes and manufacture a resin molded product of a predetermined shape at low cost. In this case, the quantum-dot-containing resin includes metal soap (preferably calcium stearate), it is possible to increase dispersibility of particles of quantum dots and improve durability with respect to environmental changes. Note that an example using quantum dots that emit green light and quantum dots that emit red light when blue light is radiated has been described as an application using the resin molded product according to the present embodiment, but the application is not limited to this. That is, as the resin molded product in the present embodiment, a resin molded product containing quantum dots and fluorescent substances other than the quantum dots can also be used for the applications in <FIG>. For example, when blue light is radiated, a red light emission fluorescent substance that emits red light can be used instead of red light emission quantum dots that emit red light. Alternatively, a green light emission fluorescent substance that emits green light can be used instead of green light emission quantum dots that emit green light. Furthermore, the application using the resin molded product according to the present embodiment is not limited to the wavelength conversion member that converts the wavelength of light emitted from a light-emitting device such as an LED. For example, the resin molded product of the present embodiment may be used for a light-emitting apparatus that converts electric energy to light through quantum dots. Alternatively, the resin molded product of the present embodiment may be used for a photoelectric conversion apparatus that converts light to electric energy through quantum dots.

The method for manufacturing a resin molded product according to the present embodiment has a feature of molding a resin composition obtained by dispersing quantum dots in resin. A specific manufacturing method thereof will be described using <FIG> is a flowchart illustrating the method for manufacturing a resin molded product according to the present embodiment.

In step ST1 in <FIG>, a PP mixture is generated by stirring, for example, polypropylene (PP) as resin, elastomer and metal soap. As the metal soap, use of calcium stearate is suitable. It is possible to arbitrarily determine whether or not to contain elastomer. Metal soap may be suitably contained to improve dispersibility of quantum dots as shown in an experiment which will be described later.

Next, in step ST2 in <FIG>, quantum dots (QD) are dispersed in a solvent and a QD liquid is generated. Here, organosilane or hexane is suitably used as the solvent.

Next, in step ST3 in <FIG>, the PP mixture generated in ST1 is mixed with the QD liquid generated in ST2 and the mixture is stirred until it becomes uniform.

Next, in step ST4 in <FIG>, the mixture obtained in ST3 is introduced into an extruder, the mixture is extruded and kneaded at a predetermined temperature and the wire obtained is introduced into a cutter and a pellet is created (ST5).

In step ST6 in <FIG>, the pellet is introduced into an injection molding machine which is set to a predetermined cylinder temperature, injected into a metal die and a resin molded product is created.

According to the method for manufacturing a resin molded product of the present embodiment described above, it is possible to freely create molded products of various shapes using quantum-dot-containing resin.

The present embodiment mixes the metal soap when generating the PP mixture in ST1 in order to increase dispersibility of quantum dots. The metal soap wraps the quantum dots in the resin. The metal soap is distributed around the quantum dots and the dispersibility of the quantum dots in the resin thereby further improves. For example, instead of mixing the metal soap during injection molding in ST6, the PP mixture into which the metal soap is introduced is extruded and kneaded. Thus, dispersibility of quantum dots with respect to resin in the resin molded product effectively increases.

The order of steps ST1 and ST2 shown in <FIG> is not particularly determined as long as ST1 and ST2 come before ST3. Note that ST3 to ST6 are executed in the order in <FIG>.

Furthermore, for example, instead of generating the PP mixture beforehand as shown in ST1, after generating the QD solution in ST2, polypropylene, elastomer and metal soap may be mixed into the QD solution. In this case, the order in which polypropylene, elastomer and metal soap are mixed is not determined.

Furthermore, according to the present embodiment, a scattering agent may be mixed into the QD solution. Minute particles of silica (SiO<NUM>), BN, AlN or the like can be presented as the scattering agent.

Hereinafter, examples and comparative examples implemented to clarify the effects of the present invention will be described in detail. Note that the present invention will not be limited by the following examples at all. For example, although examples will be described in the following examples where a resin molded product is molded by injection molding, the resin molded product of the present invention may also be created using methods such as extrusion molding, hollow molding, thermoforming, compression molding, calendar molding, inflation method or casting method.

The following materials were used to create the following resin molded product.

<NUM> of QD was dispersed into <NUM> of organosilane, <NUM> thereof was added to <NUM> of the PP mixture and the rest of operation conducted was similar to that of sample <NUM>-<NUM>. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

The same operation as that in sample <NUM>-<NUM> was conducted except using the QD liquid used in sample <NUM>-<NUM> having a QD concentration of <NUM> ppm diluted ten times with organosilane. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

The mixing condition and the extrusion condition were changed using the same raw materials as those of sample <NUM>-<NUM>. To be more specific, PP and elastomer were mixed with the QD liquid. The extrusion temperature was raised to sufficiently evaporate organosilane more than in sample <NUM> and the extrusion speed was decreased. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

Sample <NUM>-<NUM> was created using a method similar to that of sample <NUM>-<NUM> but calcium stearate was not used. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

Sample <NUM> was created using a method similar to that of sample <NUM>-<NUM>. However, hexane was used as a solvent to disperse QD. Use of hexane helps QD disperse well, and even when PP was mixed with elastomer, there was less stickness. The QD concentration in sample <NUM> was <NUM> ppm.

Sample <NUM>-<NUM> was created using a method similar to that in sample <NUM>. However, the QD concentration was set to <NUM> ppm.

Sample <NUM>-<NUM> was created using a method similar to that in sample <NUM>-<NUM>. However, <NUM> weight% of silica minute particles (SiO<NUM> minute particles having a particle diameter of <NUM>) was added as a scattering agent. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

Sample <NUM>-<NUM> was created using a method similar to that in sample <NUM>-<NUM>. However, <NUM> weight% of silica minute particles was added as the scattering agent. The QD concentration in sample <NUM>-<NUM> was <NUM> ppm.

A wire-like sample having a length of <NUM> was sandwiched by a sample holder provided with three blue (wavelength: <NUM>) LEDs, the LEDs were turned on under the following conditions and a time variation in light emission intensity from each sample was traced.

Note that a thermo-hygrostat IW222 manufactured by YAMATO Scientific Co. was used for a durability test under <NUM> 90RH. Regarding light emission intensity, each sample was sandwiched by a sample holder provided with three blue (wavelength: <NUM>) LEDs and when the LEDs were caused to emit light with LED excitation light of <NUM> (<NUM> mW×<NUM>), a total luminous flux was measured using a total luminous flux measuring system manufactured by OTSUKA ELECTRONICS Co.

Table <NUM> below shows experiment results of samples <NUM>-<NUM> and <NUM>-<NUM>.

<FIG> illustrates an example of light emission spectrum. <FIG> shows a light emission spectrum of sample <NUM>-<NUM> measured under a condition of <NUM> atmosphere, with elapsed times of <NUM>, <NUM>, <NUM>, <NUM> and <NUM> hours. A light emission spectrum over time under other durability test conditions was also obtained and the results were summarized in above Table <NUM>. Note that although Table <NUM> and <FIG> describe results of elapsed times of up to <NUM> hours, time variations in light emission intensity exceeding <NUM> hours were actually measured. <FIG> show the experiment results.

<FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition and <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition.

<FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition.

Next, Table <NUM> below shows experiment results when sample <NUM> was irradiated with light emitted under a temperature of <NUM>, humidity of <NUM>% and at <NUM> mA, and Table <NUM> shows experiment results under other conditions.

<FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM> (red area) under each condition.

In each graph, the smaller the time variation in light emission intensity, that is, the gentler the gradient of reduction over an elapsed time, the more the durability against environmental variations improves. As is obvious from each graph, it is appreciated that when the LED is turned on under severe environmental conditions such as <NUM>, 90RH, fluorescence intensity decreases rapidly. On the other hand, it is appreciated that when the LED is turned on indoors, when the LED is turned on under a <NUM> atmosphere or when the LED is not turned on, fluorescence intensity gradually attenuates or the initial intensity level can be maintained.

Next, a time variation in fluorescence intensity of sample <NUM>-<NUM> mixed with calcium stearate (StCa) was compared with that of sample <NUM>-<NUM> without being mixed with calcium stearate (StCa). <FIG> show experiment results of sample <NUM>-<NUM>, and <FIG> show experiment results of sample <NUM>-<NUM>. When the graphs are compared under the same condition, it is possible to appreciate that durability has improved in sample <NUM>-<NUM> mixed with calcium stearate (StCa) compared to sample <NUM>-<NUM> not mixed with calcium stearate (StCa). With the samples mixed with calcium stearate in particular, the peak areas of the green light and the red light remained <NUM>% or more of those before testing under a temperature of <NUM>, a humidity of <NUM>% without turning on the LED even after a lapse of time of <NUM> hours. Furthermore, with these samples, the peak intensities of the green light and the red light remained <NUM>% or more of those before testing under a temperature of <NUM>, a humidity of <NUM>% without turning on the LED even after a lapse of time of <NUM> hours.

Furthermore, the time variations in fluorescence intensity in <FIG> showing experiment results of sample <NUM>-<NUM> using organosilane as a solvent were compared with the time variations in fluorescence intensity in <FIG> showing experiment results of sample <NUM> using hexane as a solvent. When the graphs are compared under the same condition, it is possible to appreciate that durability has been likely to improve in sample <NUM> using hexane as the solvent compared with sample <NUM>-<NUM> using organosilane as the solvent. With the sample using hexane and mixed with calcium stearate, the peak areas of the green light and the red light remained <NUM>% or more of those before testing under a temperature of <NUM>, a humidity of <NUM>% without turning on the LED even after a lapse of <NUM> hours.

The following injection molding machine was used.

Pellets of samples <NUM>-<NUM> to <NUM>-<NUM> obtained through extrusion molding were introduced to an injection molding machine under a cylinder temperature of <NUM> to <NUM>, injected into a physical property specimen creation metal die to mold a specimen of a predetermined shape.

The respective specimens were heated to <NUM>, <NUM>, <NUM>, respectively, and then annealed. The specimen in size of <NUM>×<NUM>×<NUM> was held by a sample holder, and subjected to a durability test under <NUM>, 90RH. Influences of the above-described annealing were thereby studied.

<FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (green area) under each condition. <FIG> is a graph illustrating a time variation in light emission intensity of sample <NUM>-<NUM> (red area) under each condition.

As shown in <FIG>, <FIG> and <FIG>, no significant differences were observed in red light emission. On the other hand, as shown in <FIG>, <FIG> and <FIG>, regarding green light emission, it has been appreciated that samples to which silica minute particles were added emitted light more hours than sample <NUM>-<NUM> to which no silica minute particles were added. Note that there was no significant change before and after the annealing in the reduction in the fluorescence area and no significant improvement was observed.

The dispersed state of quantum dots in resin was examined using sample A. Sample A was formed based on sample <NUM>-<NUM>. Both <FIG> and <FIG> are TEM photographs. <FIG> is an enlarged view of the aggregate of quantum dots shown in <FIG>. <FIG> is a schematic view of <FIG> and <FIG> is a schematic view of <FIG>.

It has been proved from this experiment that a plurality of quantum dots form each aggregate and aggregates are dispersed in resin.

The resin molded product produced according to the manufacturing method of the present invention is applicable to a light-guiding board for an LED light source, a backlight or the like, and an illumination device, a fluorescence member or the like.

Claim 1:
A method for manufacturing a resin molded product for a backlight of a display, the method comprising:
extrusion molding a resin composition, obtained by mixing the resin and metal soap with a quantum dot liquid,
wherein the quantum dot liquid is obtained by dispersing the quantum dots in a solvent, wherein the resin contains a dispersant made of metal soap.