JP2008010402A - Light-emitting element and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element which has high light extraction efficiency and high luminance, and which can save power consumption, and to provide a display device. <P>SOLUTION: The light-emitting element is constituted of a light-emitting layer, between a first electrode and a second electrode facing each other. A dielectric layer is provided, at least in between the first electrode and the light-emitting layer, and light dispersing fine particles are dispersed on the dielectric layer. Light emitted from the light-emitting layer is extracted from the first electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting element that emits light by application of electric energy and a display device including the light emitting element.

  In recent years, the improvement of flat panel displays typified by liquid crystal displays has progressed, and improvements in image quality, low power consumption, long life, and the like have been achieved. However, the liquid crystal used in the liquid crystal display is not self-luminous, and a liquid crystal layer is formed between a pair of substrates, a light source (backlight) is applied from one side of the pair of substrates, and the light from the light source is liquid crystal. Images are obtained by controlling transmission or blocking. Therefore, in addition to the original control of the liquid crystal, a large electric energy is required because a separate light source is used.

  Therefore, an electroluminescence element (hereinafter referred to as an EL element) has been attracting attention as one of self-luminous light emitting elements. EL elements have advantages such as thinness and light weight in addition to self-luminous properties, and are being studied. In the liquid crystal display, it is necessary to provide a color conversion layer called a color filter on the surface of the liquid crystal layer in order to achieve colorization. On the other hand, the EL element can exhibit various light emission such as red, green, and blue depending on individual materials. Therefore, in the liquid crystal display, light from the light source is attenuated by the color filter, whereas in the EL element, there is an advantage that full color can be easily achieved without using the color filter.

  The light emitting element is distinguished depending on whether the light emitting material is an organic compound or an inorganic compound, and the former is generally called an organic light emitting element and the latter is called an inorganic light emitting element. Furthermore, inorganic light-emitting elements are classified into thin-film type inorganic light-emitting elements and dispersion-type inorganic light-emitting elements depending on the element structure. The former has a light emitting layer made of a thin film of a light emitting material, and the latter has a difference in that it has a light emitting layer in which a particulate light emitting material is dispersed in a binder. Note that the light emission mechanism obtained by both light emitting elements includes donor-acceptor recombination light emission using a donor level and an acceptor level and localized light emission using inner-shell electronic transition of a metal ion. . In general, thin-film inorganic light-emitting elements often have localized light emission, and dispersed inorganic light-emitting elements often have donor-acceptor recombination light emission.

  Realization of a display that can display brightly and vividly with low power consumption in order to take advantage of the light-emitting element's self-emission characteristics, when an electroluminescence panel (hereinafter also referred to as an EL panel) using light-emitting elements as pixels is put into practical use. It has been demanded. In order to meet the demand, improvement in power efficiency has been promoted by improving current luminance characteristics of materials used for light emitting elements, but the above-described method has a limit in improving power efficiency.

  Not all of the light emitted from the light emitting layer of the light emitting element is emitted to the outside, and part of the light is totally reflected when it passes through the interface of films having different refractive indexes. Then, the totally reflected light is absorbed and attenuated inside the light emitting element, so that the light extraction efficiency to the outside is lowered.

Patent Document 1 describes an EL element in which the light extraction efficiency is improved by reducing the total reflection amount. In Patent Document 1, by providing a film in which particles are dispersed on a transparent electrode layer, light passing through the film is scattered by the particles, and light incident on the interface between the transparent electrode layer and the low refractive index film is critical. Try not to fill the corner.
JP 2004-303724 A

  The present invention provides a light-emitting element having high light extraction efficiency by reducing the amount of light totally reflected by the light-emitting layer by means different from Patent Document 1 and improving the amount of light extracted to the outside. This is the issue. It is another object of the present invention to provide a light-emitting element and a display device with high luminance and low power consumption.

  The light-emitting element of the present invention has a light-emitting layer between a first electrode and a second electrode facing each other. In addition, a dielectric layer is provided between at least the first electrode and the light emitting layer, and light scattering particles are dispersed in the dielectric layer. Light emitted from the light emitting layer is extracted from the first electrode to the outside.

  In the light-emitting element having the above structure, a dielectric layer may be provided between the second electrode and the light-emitting layer. Further, two dielectric layers in which light scattering particles are dispersed may be provided between the first electrode and the light emitting layer.

  Another structure of the light-emitting element of the present invention has a light-emitting layer between a first electrode and a second electrode facing each other, and the light-emitting layer includes a particulate light-emitting material and light-scattering fine particles in a binder. It has a distributed structure. Light emitted from the light emitting layer is extracted from the first electrode to the outside.

  In the light-emitting element having the above structure, a dielectric layer in which light-scattering fine particles are further dispersed may be provided between the first electrode and the light-emitting layer.

  The light scattering fine particles are fine particles formed using an organic material or an inorganic material. The refractive index of the light scattering fine particles is preferably the same as or higher than the refractive index of the first electrode from which light is extracted. In addition, the refractive index of an electrode means the refractive index of this single layer film, when an electrode is a single layer film. When a multilayer film is used, it means the refractive index of the outermost layer with respect to the light emitting element.

  The size (particle size) of the light-scattering fine particles is preferably such a size that the light emitted from the light-emitting layer can be refracted and scattered so as to pass through the interface between the dielectric layer and the first electrode. Specifically, the average size of the light scattering fine particles is 2 nm or more, more preferably 20 nm or more. Moreover, it is preferable that the size of the fine particles does not exceed a wavelength in the visible wide range. Specifically, the average size of the light scattering fine particles is preferably 800 nm or less, and is preferably 100 nm or less in consideration of the optical design of the light emitting element.

  In addition, the first electrode is preferably a light-transmitting electrode in order to extract light emitted from the light-emitting layer.

  According to the present invention, by providing a plurality of fine particles having a predetermined refractive index in a dielectric layer or a light emitting layer, a critical angle of light passing through the dielectric layer from the light emitting layer or a light emitting material dispersed in the light emitting layer is obtained. The critical angle of light passing through the light emitting layer is diversified. Conventionally, the light totally reflected at the interface with the electrode can be taken out. Therefore, the light extraction efficiency of the light emitting element can be improved.

  In order to prevent the light passing through the light scattering fine particles from causing total reflection at the interface with the electrode, the refractive index of the light scattering fine particles is preferably equal to or higher than the refractive index of the electrode.

  The display device of the present invention includes the light-emitting element having the above structure between a first substrate and a second substrate facing each other, and takes out light from the light-emitting element from the first substrate. In addition, a sealant for sealing the light emitting element is provided between the first substrate and the second substrate.

  The sealing material is provided in the periphery of the first substrate and the second substrate, and a region between the first substrate and the second substrate and surrounded by the sealing material is filled with gas. Or a solid is preferably provided. When the gas is filled, it is preferable to use an inert gas such as nitrogen or argon as the gas. When a solid is provided, it is preferable to use a resin as the solid.

  In addition, the first substrate is preferably a substrate having a high transmittance with respect to visible light in order to extract light emitted from the light-emitting element. Specifically, the first substrate preferably has a transmittance of 80% or more with respect to visible light.

  According to the present invention, since the amount of light totally reflected when light emitted from the light emitting layer is extracted from the electrode is reduced, the light extraction efficiency of the light emitting element can be improved. In addition, by providing a light-emitting element having high light extraction efficiency, high luminance and low power consumption of the display device can be realized.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention can be implemented in many different ways. It will be readily understood by those skilled in the art that various changes can be made in form and detail without departing from the spirit and scope of the invention. The present invention is not construed as being limited to the description of this embodiment mode.

  Moreover, it is possible to combine each embodiment suitably, without deviating from the meaning of this invention. In different embodiments, since common elements have been described with the same reference numerals, the description may be omitted.

(Embodiment 1)
In this embodiment mode, a mode using a thin film type inorganic light emitting device which is one of the light emitting devices of the present invention is shown. FIG. 1A is a cross-sectional view of a display device using a top emission structure. FIG. 1B is a cross-sectional view of a display device using a bottom emission structure. Note that in this specification, the top emission structure refers to a structure in which light emission from the light-emitting element is extracted from above (on the sealing substrate side). On the other hand, the bottom emission structure refers to a structure in which light emitted from the light-emitting element is extracted from below (the substrate side on which the element is provided).

  In the following embodiment, in FIGS. 1A and 1B, the positions of the reflective electrode 103 and the transmissive electrode 105 and the positions of the first dielectric layer 107 and the second dielectric layer 108 are opposite. Since the formation order is merely reversed, the top emission structure will be described with reference to FIG. 1A unless otherwise specified.

  FIG. 1A is a cross-sectional view of a display device provided with the light-emitting element of the present invention. A light emitting element 120 is provided over the substrate 101.

  In the light emitting element 120, the reflective electrode 103, the first dielectric layer 107, the light emitting layer 104, the second dielectric layer 108, and the transmissive electrode 105 are laminated in this order from the substrate 101 side. A plurality of light scattering particles 106 are dispersed in the second dielectric layer 108.

  In addition, the light-emitting layer 104 of the light-emitting element 120 is preferably separated by an insulating layer 114 and a partition layer 115 that cover part of the reflective electrode 103. In the present embodiment, the first dielectric layer 107, the light emitting layer 104, the second dielectric layer 108, and the transmissive electrode 105 are separated by the insulating layer 114 and the partition layer 115. Further, a separated first dielectric layer 157, light emitting layer 154, second dielectric layer 158, and transmissive electrode 155 are stacked on the partition layer 115. The partition wall layer 115 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 115 is trapezoidal, and the bottom side (the side facing the insulating layer 114 in the same direction as the surface direction of the insulating layer 114) is the upper side (the surface of the insulating layer 114). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 114. Thus, by providing the partition layer 115, the transmissive electrode 105 can be insulated from the adjacent transmissive electrode. Note that the insulating layer 114 and the partition layer 115 are not necessarily provided.

  In addition, a sealing substrate 112 is fixed to the substrate 101 by a sealing material 111 provided in the periphery of the substrate 101, and the light emitting element 120 is sealed. In this embodiment, a gas 113 is filled in a space hermetically sealed by the substrate 101, the sealing material 111, and the substrate 112. As the gas 113 filling the space, an inert gas such as nitrogen or argon is preferable.

  The substrate 101 only needs to be a support base of the light-emitting element 120, and a quartz substrate, a semiconductor substrate, a glass substrate, a plastic substrate, a flexible plastic film, or the like can be used.

  As the sealing substrate 112, a quartz substrate, a semiconductor substrate, a glass substrate, a plastic substrate, a flexible plastic film, or the like can be used. In this embodiment, a flat substrate is used as the sealing substrate 112. However, the shape is not limited to this, and it is sufficient that the light emitting element can be sealed. For example, a cap-like thing such as a sealing can can be used.

  In the case where the sealing substrate 112 is a substrate from which light is extracted, it is preferable to use a substrate having high transmittance with respect to visible light. Specifically, it is preferable to use a substrate having a transmittance of 80% or more for visible light. Here, this corresponds to the case of the top emission structure shown in FIG. 1A, and the electrode closest to the substrate 112 is a light-transmitting electrode (transmission electrode 105). At this time, the substrate 101 is an electrode in which the nearest electrode is reflective (reflective electrode 103), and is a substrate on the side from which light is not extracted. Therefore, the substrate 101 does not need to be transparent, and may be colored or opaque.

  In the case where the substrate 101 serves as a substrate from which light is extracted, it is preferable to use a substrate having a high transmittance with respect to visible light. Specifically, it is preferable to use a substrate having a transmittance of 80% or more for visible light. Here, this corresponds to the bottom emission structure shown in FIG. 1B, and the electrode closest to the substrate 101 is a light-transmitting electrode (transmission electrode 105). At this time, the sealing substrate 112 is an electrode in which the nearest electrode is reflective (the reflective electrode 103), and is a substrate on the side from which light is not extracted. Therefore, the substrate 112 does not need to be transparent, and may be colored or opaque.

  Note that in the case where the substrate 101 or the sealing substrate 112 is a substrate on which light is extracted, a color filter is provided on the substrate from which light is extracted to improve the color purity of the light-emitting element or the light-emitting color of the light-emitting element. May be converted.

  Note that the display device illustrated in FIGS. 1A and 1B is a passive matrix pixel; for example, the display device illustrated in FIGS. 1A and 1B is provided in an active matrix pixel. In such a case, a circuit including a transistor, a capacitor, and the like for controlling the luminance of the light emitting element 120 and the timing of light emission can be provided below the light emitting element 120.

  A reflective electrode 103 is formed on the substrate 101. The reflective electrode 103 has a function of reflecting light emitted from the light emitting layer, and functions as a cathode. The reflective electrode 103 is formed of a reflective conductive film such as a metal or an alloy. As this metal film, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu) Palladium (Pd), aluminum (Al), and the like. Further, examples of the alloy film include an alloy of magnesium and silver, an alloy of aluminum and lithium, and the like. The film for forming these reflective electrodes 103 can be formed by sputtering or vapor deposition.

  Alternatively, the reflective electrode 103 can be formed of a multilayer film in which a transparent conductive film is stacked on the metal film or alloy film, or a multilayer film in which the metal film or alloy film is sandwiched between two transparent conductive films. Furthermore, a multilayer film made of transparent conductive films having different refractive indexes can be used for the reflective electrode 103. High reflectivity is realized by using optical multiple interference.

  A first dielectric layer 107 is formed on the reflective electrode 103. The first dielectric layer 107 is made of an insulating material and is not particularly limited, but preferably has a high withstand voltage and a dense film quality. Furthermore, it is preferable that the dielectric constant is high. For example, yttrium oxide, titanium oxide, aluminum oxide, hafnium oxide, tantalum oxide, barium titanate, strontium titanate, lead titanate, silicon nitride, zirconium oxide, etc., or a mixed film of these or two or more kinds of laminated films are used. Can do. The first dielectric layer 107 can be formed using these materials by a sputtering method, an evaporation method, a CVD method, a droplet discharge method (typically, an inkjet method), or the like.

  A light emitting layer 104 is formed on the first dielectric layer 107. The light emitting layer 104 is a layer made of a thin film of a light emitting material. A light emitting material that can be used in this embodiment includes a base material and an impurity element. By changing the impurity element to be contained, light emission of various colors can be obtained. As a method for manufacturing the light-emitting material, various methods such as a solid phase method and a liquid phase method (coprecipitation method) can be used. Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, method combining these methods with high temperature firing, liquid phase method such as freeze-drying method, etc. can be used.

  The solid phase method is a method in which a base material and an impurity element or a compound containing the impurity element are weighed, mixed in a mortar, heated and fired in an electric furnace, reacted, and the base material contains the impurity element. The firing temperature is preferably 700 ° C to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. Although firing at a relatively high temperature is required, it is a simple method, so it has high productivity and is suitable for mass production.

  The liquid phase method (coprecipitation method) is a method in which a base material or a compound containing the base material and an impurity element or a compound containing the impurity element are reacted in a solution, dried, and then fired. The particles of the luminescent material are uniformly distributed, and the reaction can proceed even at a low firing temperature with a small particle size.

  As a base material used for the light-emitting material, sulfide, oxide, or nitride can be used. Examples of sulfides that can be used include zinc sulfide, cadmium sulfide, calcium sulfide, yttrium sulfide, gallium sulfide, strontium sulfide, and barium sulfide. As the oxide, for example, zinc oxide, yttrium oxide, or the like can be used. As the nitride, for example, aluminum nitride, gallium nitride, indium nitride, or the like can be used. Furthermore, zinc selenide, zinc telluride, and the like can also be used, and may be a ternary mixed crystal such as calcium sulfide-gallium sulfide, strontium sulfide-gallium, barium sulfide-gallium.

  When the light-emitting element 120 shown in this embodiment is a localized light-emitting element, manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), Europium (Eu), cerium (Ce), praseodymium (Pr), or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation.

  On the other hand, when the light-emitting element 120 described in this embodiment is a donor-acceptor recombination light-emitting element, a light-emitting material including a first impurity element that forms a donor level and a second impurity element that forms an acceptor level is used. Can be used. As the first impurity element, for example, fluorine (F), chlorine (Cl), aluminum (Al), or the like can be used. For example, copper (Cu), silver (Ag), or the like can be used as the second impurity element.

  In the case where a light-emitting material for donor-acceptor recombination light emission is synthesized using a solid-phase method, a base material, a first impurity element or a compound containing the first impurity element, a second impurity element, or a second impurity element Each compound containing an impurity element is weighed and mixed in a mortar, and then heated and fired in an electric furnace. As the base material, the above-described base material can be used, and as the first impurity element or the compound containing the first impurity element, for example, fluorine (F), chlorine (Cl), aluminum sulfide, or the like is used. Can do. As the second impurity element or the compound containing the second impurity element, for example, copper (Cu), silver (Ag), copper sulfide, silver sulfide, or the like can be used. The firing temperature is preferably 700 ° C to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state.

  In addition, as an impurity element in the case of using a solid phase reaction, a compound including a first impurity element and a second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. As the compound including the first impurity element and the second impurity element, for example, copper chloride, silver chloride (AgCl), or the like can be used.

  Note that the concentration of these impurity elements may be 0.01 atom% to 10 atom% with respect to the base material, and is preferably in the range of 0.05 atom% to 5 atom%.

  The light-emitting element 120 in this embodiment is a thin-film inorganic light-emitting element, and the light-emitting layer 104 is a layer containing the above light-emitting material. Its formation method includes chemical vapor deposition such as resistance heating vapor deposition, electron beam vapor deposition (EB vapor deposition), physical vapor deposition (PVD) such as sputtering, organometallic CVD, and hydride transport low pressure CVD. It can be formed by vapor deposition (CVD), atomic layer epitaxy (ALE), or the like.

  A second dielectric layer 108 is formed on the light emitting layer 104. Light scattering particles 106 are dispersed in the second dielectric layer 108. The second dielectric layer 108 is made of an insulating material and is not particularly limited, but preferably has a high withstand voltage and a dense film quality. Furthermore, it is preferable that the dielectric constant is high. For example, yttrium oxide, titanium oxide, aluminum oxide, hafnium oxide, tantalum oxide, barium titanate, strontium titanate, lead titanate, silicon nitride, zirconium oxide, etc., or a mixed film of these or two or more kinds of laminated films are used. Can do. The second dielectric layer 108 is formed using these materials mainly using a wet method. For example, the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed is formed by a droplet discharge method, a spin coating method, a dip coating method, a printing method, or the like.

The light scattering fine particles 106 are made of a material having a refractive index equal to or higher than the refractive index of the transmissive electrode 105, and may be either an organic material or an inorganic material. For example, there is an oxide of an element selected from zinc (Zn), indium (In), and tin (Sn), or a compound obtained by adding a dopant to these oxides. Examples of the zinc oxide dopant include Al, Ga, B, and In. Note that zinc oxide (ZnO) containing these dopants is called AZO, GZO, BZO, and IZO, respectively. Examples of the indium oxide dopant include Sn and Ti. Indium oxide to which Sn is added is called ITO (Indium Tin Oxide). Examples of the tin oxide dopant include Sb and F. Other examples include metal oxides such as strontium oxide, aluminum oxide, titanium oxide, yttrium oxide, and cesium oxide. Various ferroelectric materials can be used. For example, there are oxide ferroelectric materials such as barium titanate, potassium niobate, and lithium niobate. Further, silicon oxide, silicon nitride, silicon nitride oxide (SiN _x O _y , 0 <x <4/3, 0 <y <2, 0 <3x + 2y ≦ 4), zirconia, DLC (diamond-like carbon), carbon nanotube, etc. However, since it is dispersed in the dielectric layer, a material having a high dielectric property is preferable.

  The size (particle size) of the light-scattering fine particles 106 is such that light having an incident angle that has been totally reflected at the interface between the dielectric layer and the transmissive electrode in the past is refracted and scattered, so that the dielectric layer and the transmissive electrode It is necessary to have such a size that the effect of allowing it to pass through the interface is obtained. Specifically, the size of the light scattering fine particles 106 is 2 nm or more on average, more preferably 20 nm or more. The size of the light scattering fine particles 106 preferably does not exceed the wavelength in the visible light region, and the upper limit is 800 nm on average. Considering the optical design of the light emitting element, it is preferable to set the upper limit to an average of 100 nm.

  The shape of the light-scattering fine particles 106 is preferably a shape in which an action of condensing or scattering light appears. For example, a columnar shape, a polyhedron shape, a polygonal pyramid shape such as a triangular pyramid, a conical shape, a concave lens shape, a convex lens shape, a kamaboko shape, a prism shape, a spherical shape, and a hemispherical shape.

  A plurality of light scattering fine particles 106 are dispersed in the second dielectric layer 108, but all the light scattering fine particles 106 need not have the same material, size, and shape, and may be different from each other.

  A transmissive electrode 105 is formed on the second dielectric layer 108. The transmissive electrode 105 functions as an anode and can transmit light emitted from the light emitting layer 104. Light emitted from the light emitting layer 104 passes through the second dielectric layer 108 or is reflected by the reflective electrode, then passes through the second dielectric layer 108, and is extracted from the transmissive electrode 105.

  The transmissive electrode 105 is formed of a transparent conductive film. The material used is a material having a high transmittance with respect to light in the visible light range (400 nm to 800 nm), and is typically a metal oxide. For example, there is an oxide of an element selected from zinc (Zn), indium (In), and tin (Sn), or a compound obtained by adding a dopant to these oxides. Examples of the zinc oxide dopant include Al, Ga, B, and In. Note that zinc oxides containing these dopants are called AZO, GZO, BZO, and IZO, respectively. Examples of the indium oxide dopant include Sn and Ti. Indium oxide to which Sn is added is called ITO (Indium Tin Oxide). Examples of the tin oxide dopant include Sb and F. Furthermore, as the transparent conductive film, a compound in which two kinds of oxides selected from the above oxides containing zinc oxide, indium oxide, tin oxide, and dopant can be used.

  In this embodiment, in order to separate the light emitting element 120, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed. The insulating layer 114 can be formed by a photolithography method and an etching method using an inorganic insulating material, an organic insulating material, or the like. The material of the partition wall 115 is not particularly limited, but for example, it is preferably formed by a photolithography method using a positive photosensitive resin in which an unexposed portion remains. In this case, the partition wall layer having a preferable inclination angle can be formed by adjusting the exposure amount or the development time so that the lower part of the partition wall layer 115 is etched faster. Needless to say, the partition layer 115 may be formed by a photolithography method and an etching method using an inorganic insulating material, an organic insulating material, or the like.

  The height (film thickness) of the partition wall layer 115 is set to be larger than the total thickness of the first dielectric layer 107, the light emitting layer 104, the second dielectric layer 108, and the transmissive electrode 105. As a result, the light-emitting element 120 separated into a plurality of electrically independent regions can be formed only by forming the light-emitting layer 104, the second dielectric layer 108, and the transmissive electrode 105 over the entire surface of the substrate 101. it can. Therefore, the number of processes can be reduced. Note that a first dielectric layer 157, a light emitting layer 154, a second dielectric layer 158, and a transmissive electrode 155 are formed over the partition layer 115, and these are the first dielectric layers constituting the light emitting element 120. 107, the light emitting layer 104, the second dielectric layer 108, and the transmissive electrode 105 are separated.

  In order to seal the light emitting element 120, a substrate 112 provided with an uncured sealing material 111 in the peripheral portion is prepared. The uncured sealing material 111 is provided around the substrate 112 in a predetermined shape by a printing method, a dispenser method, or the like. The sealing material 111 can be provided on the substrate 101 side after the transmissive electrode 105 is formed.

  As the sealing material 111, a photo-curing resin such as UV such as an epoxy resin or an acrylic resin, or a thermosetting resin can be used. Depending on the properties of the light emitting layer 104, it is preferable to use a photocurable resin and a thermosetting resin properly.

  The substrate 101 on which each layer is formed and the substrate 112 are overlapped. While applying pressure to the substrate 101 and the substrate 112, the uncured sealing material 111 is irradiated with UV light to be cured, and the substrate 101 and the substrate 112 are fixed. Of course, when a thermosetting resin is used for the sealant 111, heat treatment is performed. In addition, it is desirable that the atmosphere in which the treatment is performed is slightly reduced from the atmospheric pressure until the sealing material 111 is cured from when the substrate 101 and the substrate 112 are overlapped. Further, it is desirable that the atmosphere in which the treatment is performed contain as little moisture as possible, for example, a nitrogen atmosphere may be used.

  By curing the sealing material 111, the space between the substrate 101 and the substrate 112 is hermetically sealed and filled with the gas 113.

  After sealing the substrate 101 with the substrate 112, the substrate 112 is divided into an arbitrary panel size.

  In the present embodiment, the light extraction efficiency from the light emitting element 120 is improved by dispersing a large number of light scattering particles 106 in the second dielectric layer 108 provided between the transmissive electrode 105 and the light emitting layer 104. Can do. This is because when the light emitted from the light emitting layer 104 passes through the second dielectric layer 108, the incident angle of the light changes from place to place by the light scattering fine particles 106, and is refracted and scattered. This is because light having an incident angle that has been totally reflected at the interface between the body layer 108 and the transmissive electrode 105 can pass therethrough. As described above, the light scattering fine particles 106 are dispersed in the second dielectric layer 108, so that the amount of light totally reflected at the interface between the second dielectric layer 108 and the transmissive electrode 105 is reduced, and light emission. It is a feature of the present invention that the light extraction efficiency of the element 120 is improved.

  Patent Document 1 describes that light extraction efficiency is improved by providing a particle-containing transparent electrode layer in which fine particles are dispersed on the transparent electrode layer. That is, in Patent Document 1, light is scattered by fine particles in the particle-containing transparent electrode layer to change the light angle to an angle that does not totally reflect, thereby improving the extraction efficiency. On the other hand, in the invention proposed in this specification, light is incident on the interface of the transmissive electrode 105 by the light scattering fine particles 106 dispersed in the second dielectric layer 108 provided between the transmissive electrode 105 and the light emitting layer 104. The angle is changed to improve the light extraction efficiency, and the invention disclosed in this specification is completely different from Patent Document 1.

  The light-emitting element according to this embodiment can improve the light extraction efficiency to the outside because light emitted from the light-emitting layer can reduce the amount of light totally reflected at the interface between the transmissive electrode and the dielectric layer. Can do.

  In addition, since the display device according to this embodiment includes a light-emitting element having high light extraction efficiency, high luminance and low power consumption can be realized.

(Embodiment 2)
In this embodiment mode, a mode in which the present invention is used for a dispersed inorganic light-emitting element which is one of light-emitting elements is shown. FIG. 2A is a cross-sectional view of a display device using a top emission structure. FIG. 2B is a cross-sectional view of a display device using a bottom emission structure. In FIGS. 2A and 2B, the positions of the reflective electrode 103 and the transmissive electrode 105 are reversed, and the formation order thereof is only reversed. Therefore, unless otherwise specified, FIG. ).

  In Embodiment Mode 1, the reflective electrode 103, the first dielectric layer 107, the light emitting layer 104, the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed, and the transmissive electrode 105 are provided between the substrate 101 and the substrate 112. The structure in which the light emitting element 120 having the above is formed has been described. In this embodiment, the first dielectric layer 107, the light emitting layer 104, and the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed are used in a form using a so-called dispersed inorganic light emitting element. Is different from the first embodiment. In other words, the light-emitting element 130 described in this embodiment includes a light-emitting layer 109 sandwiched between the reflective electrode 103 and the transmissive electrode 105, and the light-emitting layer 109 includes a particulate light-emitting material 110, light-scattering fine particles 106, and the like. Are distributed.

  First, the substrate 101 on which the reflective electrode 103 is formed by the process described in Embodiment Mode 1 is prepared.

  Next, the light emitting layer 109 is formed over the reflective electrode 103. The light emitting layer 109 is a layer in which a particulate light emitting material 110 is dispersed in a binder. In the light emitting layer 109, light scattering fine particles 106 are also dispersed in the binder. The binder is a substance for fixing the particulate light emitting material in a dispersed state and maintaining the shape as the light emitting layer. The particulate light emitting material 110 is uniformly dispersed and fixed in the light emitting layer by the binder.

  As the particulate light-emitting material 110, a material obtained by processing the light-emitting material described in Embodiment Mode 1 into particles can be used. If particles having a desired size cannot be obtained sufficiently by the method for producing a light emitting material, the particles may be processed into particles by pulverization with a mortar or the like.

  The light scattering fine particles 106 described in Embodiment Mode 1 can be used as the light scattering fine particles 106.

  As a binder used for the light emitting layer 109, an organic material or an inorganic material can be used, and a mixed material of an organic material and an inorganic material may be used. As the organic material, a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, or a resin such as polyethylene, polypropylene, polystyrene resin, silicone resin, epoxy resin, or polyvinylidene fluoride can be used. Alternatively, a heat-resistant polymer material such as aromatic polyamide, polybenzimidazole, or a siloxane resin may be used. Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. Fluorine may be used as a substituent. Alternatively, as a substituent, an organic group containing at least hydrogen and fluorine may be used. Moreover, resin materials such as vinyl resins such as polyvinyl alcohol and polyvinyl butyral, phenol resins, novolac resins, acrylic resins, melamine resins, urethane resins, and oxazole resins (polybenzoxazole) may be used. The dielectric constant can be adjusted by appropriately mixing fine particles having a high dielectric constant such as barium titanate or strontium titanate with these resins.

Examples of the inorganic material include silicon nitride (SiN _x ), silicon containing oxygen and nitrogen, aluminum nitride, aluminum containing oxygen and nitrogen, aluminum oxide, titanium oxide, barium titanate, strontium titanate, lead titanate, potassium niobate , Lead niobate, tantalum oxide, barium tantalate, lithium tantalate, yttrium oxide, zirconium oxide, zinc sulfide, and other inorganic materials. By including an inorganic material having a high dielectric constant in the organic material, the dielectric constant of the light emitting layer 109 made of the binder in which the particulate light emitting material 110 is dispersed can be further controlled, and the dielectric constant can be increased. Can do.

  In the manufacturing process, the particulate light emitting material 110 is dispersed in a solution containing a binder. As a solvent of a solution containing a binder that can be used in this embodiment mode, a binder material is dissolved to form a light emitting layer (various wet methods) and a solution having a viscosity suitable for a desired film thickness can be manufactured. A suitable solvent may be selected as appropriate. An organic solvent or the like can be used as such a solvent. For example, when a siloxane resin is used as the binder, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate (also referred to as PGMEA), 3-methoxy-3-methyl-1-butanol (also referred to as MMB), or the like can be used.

  The light-emitting element 130 of this embodiment is a dispersion-type inorganic light-emitting element, and the light-emitting layer 109 is a layer in which the particulate light-emitting material 110 and the light-scattering fine particles 106 are dispersed in a plurality of binders. As the formation method, a wet method can be mainly used. For example, it can be formed using a droplet discharge method, a printing method (screen printing, offset printing, or the like), a coating method such as a spin coating method, a dipping method, a dispenser method, or the like. In addition, the ratio of the particulate light emitting material 110 in the light emitting layer 109 may be 50 wt% or more and 80 wt% or less.

  The transmissive electrode 105 is formed over the light-emitting layer 109 using the material described in Embodiment Mode 1. Further, as in Embodiment Mode 1, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated light-emitting layer 159 and transmissive electrode 155 are stacked over the partition wall layer 115. After the transmissive electrode 105 is formed, the substrate 101 and the substrate 112 are fixed by the process described in Embodiment 1, and the substrate 112 is divided into an arbitrary panel size.

  In the present embodiment, the efficiency of extracting light from the light emitting element 130 can be improved by dispersing a large number of light scattering fine particles 106 in the light emitting layer 109. This is because when the light generated from the particulate light emitting material 110 dispersed in the light emitting layer 109 passes through the light emitting layer 109, the incident angle of light changes depending on the location, and is refracted and scattered. This is because when there is no light scattering fine particle, light having an incident angle totally reflected at the interface between the light emitting layer 109 and the transmissive electrode 105 can pass. That is, in the absence of the light scattering particles 106, light having an incident angle that is totally reflected by the transmissive electrode 105 can pass through the transmissive electrode 105. As described above, the light-scattering fine particles 106 are dispersed in the light-emitting layer 109, so that the light emitted from the particulate light-emitting material 110 similarly dispersed in the light-emitting layer 109 is totally reflected at the interface with the transmissive electrode 105. It is a feature of the present invention that the amount of light is reduced and the light extraction efficiency of the light emitting element 130 is improved.

  Thus, the light-emitting element according to this embodiment can improve light extraction efficiency to the outside. In addition, since the display device according to this embodiment includes a light-emitting element having high light extraction efficiency, high luminance and low power consumption can be realized.

(Embodiment 3)
This embodiment will be described with reference to FIG. In the first embodiment, the gas 113 is filled in the airtight space between the substrate 101 and the substrate 112. However, the display device of the present embodiment fills the space with a liquid phase material, and the liquid phase material. The solid which hardened | cured is filled. Thus, a sealing structure of a display device in which a solid is provided between substrates is called a solid sealing structure, and may be used to distinguish from a structure filled with gas. In this specification, this term will be used to distinguish from the structure filled with gas.

  The substrate 101 formed with the transmissive electrode 105 is prepared by the process described in Embodiment Mode 1 (FIG. 3A). Further, as in Embodiment Mode 1, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated first dielectric layer 157, light emitting layer 154, second dielectric layer 158, and transmissive electrode 155 are stacked on the partition layer 115.

  Next, as in Embodiment Mode 1, an uncured sealing material 111 is provided in a predetermined shape around the substrate 101 by a printing method, a dispenser method, or the like (FIG. 3B).

  In the present embodiment, the filler 201 is provided in the space between the substrate 101 and the substrate 112 that is hermetically sealed by the sealing material 111. As a material of the filler 201, a UV curable resin such as an epoxy resin or an acrylic resin, a visible light curable resin, or a thermosetting resin is used. In consideration of the heat resistance of the material of the light emitting layer 104, a UV curable resin, a visible light curable resin, or a thermosetting resin is selected. After the sealing material 111 is provided, an uncured (liquid phase) filler 201 is dropped into a region surrounded by the sealing material 111 (FIG. 3C).

  Next, the substrate 112 is overlaid on the substrate 101 on which the uncured sealing material 111 and the filler 201 are prepared. While applying pressure to the substrate 101 and the substrate 112, the uncured sealing material 111 and the filler 201 are irradiated with light or heated to cure each of them, and the substrate 112 is fixed to the substrate 101. The cured filler 201 is provided in contact with the surface of the transmissive electrode 105 and the surface of the substrate 101 to fix the substrate 112 to the substrate 101. After the sealing material 111 and the filler 201 are cured, the substrate 112 is divided into arbitrary panel sizes (FIG. 3D).

  The light-emitting element according to this embodiment has high light extraction efficiency, and a display device including such a light-emitting element can achieve high luminance and low power consumption. Further, the display device according to the present embodiment is filled with a liquid phase material, and the filled liquid phase material is cured to form a solid sealing structure. Therefore, it is possible to seal the light emitting element by sealing between the substrates without any gap, and it is possible to prevent water vapor and the like from entering the light emitting element. Therefore, deterioration of the light emitting element can be suppressed.

  In the present embodiment, the case of the top emission structure has been described, but it is of course possible to adopt a bottom emission structure. 3A to 3D, when the latter structure is used, the positions of the reflective electrode 103 and the transmissive electrode 105, the positions of the first dielectric layer 107 and the second dielectric layer 108, In addition, the formation order may be reversed.

(Embodiment 4)
This embodiment will be described with reference to FIG. In the second embodiment, the gas 113 is filled in the airtight space between the substrate 101 and the substrate 112. However, the display device of the present embodiment fills the space with a liquid phase material, and the liquid phase material. Is filled with a cured solid.

  The substrate 101 formed with the transmissive electrode 105 is prepared by the process described in Embodiment Mode 2 (FIG. 4A). Further, as in Embodiment Mode 2, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated light-emitting layer 159 and transmissive electrode 155 are stacked over the partition wall layer 115.

  Next, the sealing material 111 is provided in the periphery of the substrate 101 (FIG. 4B) and the filler 201 is provided (FIG. 4C) by the process described in Embodiment 3. After that, the substrate 101 and the substrate 112 are fixed, and the substrate 112 is divided into an arbitrary panel size (FIG. 4D).

  The light-emitting element according to this embodiment has high light extraction efficiency, and a display device including such a light-emitting element can achieve high luminance and low power consumption. Further, the display device according to the present embodiment is filled with a liquid phase material, and the filled liquid phase material is cured to form a solid sealing structure. Therefore, it is possible to seal the light emitting element by sealing between the substrates without any gap, and it is possible to prevent water vapor and the like from entering the light emitting element. Therefore, deterioration of the light emitting element can be suppressed.

  In the present embodiment, the case of the top emission structure has been described, but it is of course possible to adopt a bottom emission structure. In the case of the latter structure, the positions of the reflective electrode 103 and the transmissive electrode 105 and the order of formation thereof may be reversed in the structure described with reference to FIGS.

(Embodiment 5)
This embodiment will be described with reference to FIG. This embodiment basically has the same structure as that of the first embodiment (FIG. 1A), but a third dielectric layer 202 is added.

  A substrate 101 on which the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed is prepared by the steps described in the first embodiment. Next, the third dielectric layer 202 in which the light scattering fine particles 203 are dispersed is formed on the second dielectric layer 108.

  A transmissive electrode 105 is formed on the third dielectric layer 202. Further, as in Embodiment Mode 1, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated first dielectric layer 157, light emitting layer 154, second dielectric layer 158, third dielectric layer 252, and transmissive electrode 155 are stacked on the partition wall layer 115. After the transmissive electrode 105 is formed, the substrate 101 and the substrate 112 are fixed as in the first embodiment, and the substrate 112 is divided into an arbitrary panel size.

  For the light scattering fine particles 106, a material having a high dielectric constant and insulating property and a low refractive index is used. For example, silicon dioxide (silica) particles or the like can be used as the light scattering fine particles 106. In order to compensate for the small refractive index of the light scattering fine particles 106, it is preferable to use a material having a large refractive index for the light scattering fine particles 203 dispersed in the third dielectric layer 202. At this time, the light scattering fine particles 203 may be made of a material having a high refractive index, and a material having a low dielectric constant and insulating property can be used. For example, ITO or the like can be used as the light scattering fine particles 203. In the present embodiment, the dielectric layer provided between the transmissive electrode and the light emitting layer is formed into a two-layer structure using the second dielectric layer 108 and the third dielectric layer 202, thereby obtaining a desired dielectric layer. It is possible to form a dielectric layer having a refractive index, an insulating property, and a refractive index.

  The third dielectric layer 202 can be formed using a material similar to that of the second dielectric layer 108. That is, the third dielectric layer 202 is made of an insulating material and is not particularly limited, but preferably has a high withstand voltage and a dense film quality. Furthermore, it is preferable that the dielectric constant is high. For example, yttrium oxide, titanium oxide, aluminum oxide, hafnium oxide, tantalum oxide, barium titanate, strontium titanate, lead titanate, silicon nitride, zirconium oxide, etc., or a mixed film of these or two or more kinds of laminated films are used. Can do. The third dielectric layer 202 is formed mainly using a wet method using these materials. For example, the third dielectric layer 202 in which the light scattering fine particles 203 are dispersed is formed by a droplet discharge method, a spin coating method, a dip coating method, a printing method, or the like. In the present embodiment, the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed and the third dielectric layer 202 in which the light scattering fine particles 203 are dispersed have a two-layer structure. A dielectric layer may be provided. As in this embodiment mode, the dielectric constant provided between the transmissive electrode 105 and the light-emitting layer 104 can be adjusted to a desired dielectric constant by using two or more dielectric layers. Therefore, a sufficient amount of electric energy can be applied to the light emitting layer, and stable light emission can be obtained.

  Further, although the present embodiment is based on the structure of Embodiment 1 (FIG. 1A), it may be based on the structure of Embodiment 1 (FIG. 1B). That is, the positions of the reflective electrode 103 and the transmissive electrode 105, the positions of the first dielectric layer 107 and the second dielectric layer 108, and the formation order thereof are reversed, and the third dielectric in which the light scattering fine particles 203 are dispersed. The body layer 202 may be provided between the transmissive electrode 105 and the second dielectric layer 108.

  The light-emitting element according to this embodiment can improve light extraction efficiency to the outside. A display device including such a light-emitting element can achieve high luminance and low power consumption.

  In addition, the light-emitting element according to the embodiment can be adjusted to a desired dielectric constant by providing the dielectric layer with a stacked structure, and can emit stable light. In addition, since the display device according to this embodiment includes a light-emitting element that can obtain stable light emission, high luminance can be realized.

(Embodiment 6)
This embodiment will be described with reference to FIG. This embodiment basically has the same structure as that of the second embodiment (FIG. 2A), but a dielectric layer 602 is added.

  A substrate 101 is prepared in which the light emitting layer 109 in which the particulate light emitting material 110 and the light scattering fine particles 106 are dispersed is prepared by the process described in Embodiment Mode 2. Next, the dielectric layer 602 in which the light scattering fine particles 603 are dispersed is formed on the light emitting layer 109.

  The transmissive electrode 105 is formed on the dielectric layer 602. Further, as in Embodiment Mode 2, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated light-emitting layer 159, dielectric layer 652, and transmissive electrode 155 are stacked on the partition layer 115. After the transmissive electrode 105 is formed, the substrate 101 and the substrate 112 are bonded to each other in the same manner as in Embodiment 2 to divide the substrate 112 into an arbitrary panel size.

  For the light scattering fine particles 106, a material having a high dielectric constant and insulating property and a low refractive index is used. For example, silicon dioxide (silica) particles or the like can be used as the light scattering fine particles 106. In order to compensate for the small refractive index of the light scattering fine particles 106, it is preferable to use a material having a large refractive index for the light scattering fine particles 603 dispersed in the dielectric layer 602. At this time, the light scattering fine particles 603 may be made of a material having a large refractive index, and a material having a low dielectric constant and insulating property can be used. For example, ITO or the like can be used as the light scattering fine particles 603. The dielectric layer according to the present embodiment has a structure in which a desired dielectric constant, insulating property, and refractive index can be obtained by adopting a two-layer structure of the light emitting layer 109 and the dielectric layer 602.

  The dielectric layer 602 is made of an insulating material and is not particularly limited, but preferably has a high withstand voltage and a dense film quality. Furthermore, it is preferable that the dielectric constant is high. For example, yttrium oxide, titanium oxide, aluminum oxide, hafnium oxide, tantalum oxide, barium titanate, strontium titanate, lead titanate, silicon nitride, zirconium oxide, etc., or a mixed film of these or two or more kinds of laminated films are used. Can do. The dielectric layer 602 is formed mainly using a wet method using these materials. For example, the dielectric layer 602 in which the light scattering fine particles 603 are dispersed is formed by a droplet discharge method, a spin coating method, a dip coating method, a printing method, or the like. Note that the dielectric layer 602 may have a stacked structure of two or more layers. As in this embodiment mode, a dielectric layer 602 is further provided between the transmissive electrode 105 and the light emitting layer 109, whereby a desired dielectric constant can be adjusted. Therefore, a sufficient amount of electric energy can be applied to the light emitting layer, and stable light emission can be obtained.

  Further, in this embodiment, the structure of Embodiment 2 (FIG. 2A) is used as a basis, but the structure of Embodiment 2 (FIG. 2B) may be used as the basis. In other words, the positions of the reflective electrode 103 and the transmissive electrode 105 and the order of formation thereof may be reversed, and the dielectric layer 602 in which the light scattering fine particles 603 are dispersed may be provided between the transmissive electrode 105 and the light emitting layer 109.

  The light-emitting element according to this embodiment can improve light extraction efficiency to the outside. A display device including such a light-emitting element can achieve high luminance and low power consumption.

  In addition, the light-emitting element according to the embodiment can be adjusted to a desired dielectric constant by providing the dielectric layer with a stacked structure, and can emit stable light. In addition, since the display device according to this embodiment includes a light-emitting element that can obtain stable light emission, high luminance can be realized.

(Embodiment 7)
This embodiment is shown in FIG. The present embodiment has a solid sealing structure as in the third embodiment. The difference from Embodiment 3 is that the third dielectric layer 202 in which the light scattering fine particles 203 are dispersed is formed between the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed and the transmission electrode 105. It is a point that has been.

  The substrate 101 having the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed is prepared by the process described in the third embodiment. Next, the third dielectric layer 202 in which the light scattering fine particles 203 are dispersed is formed on the second dielectric layer 108. The light scattering fine particles 203 and the third dielectric layer 202 can be formed using the material and the manufacturing method described in Embodiment Mode 5.

  Next, the transmissive electrode 105 is formed on the third dielectric layer 202. Further, as in Embodiment Mode 3, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated first dielectric layer 157, light emitting layer 154, second dielectric layer 158, third dielectric layer 252, and transmissive electrode 155 are stacked on the partition wall layer 115. After the transmissive electrode 105 is formed, the substrate 101 and the substrate 112 are fixed using the sealant 111 and the filler 201 by the process described in Embodiment Mode 3.

  The light-emitting element according to this embodiment has high light extraction efficiency and can obtain stable light emission. A display device including such a light-emitting element can achieve high luminance and low power consumption.

(Embodiment 8)
This embodiment is shown in FIG. This embodiment has a solid sealing structure as in the fourth embodiment. A difference from the fourth embodiment is that a dielectric layer 602 in which light scattering fine particles 603 are dispersed is formed between the light emitting layer 109 in which the particulate light emitting material 110 and the light scattering fine particles 106 are dispersed, and the transmission electrode 105. It is a point that has been.

  The substrate 101 is prepared in which the light emitting layer 109 in which the particulate light emitting material 110 and the light scattering fine particles 106 are dispersed is prepared by the process described in Embodiment Mode 4. Next, the dielectric layer 602 in which the light scattering fine particles 603 are dispersed is formed on the light emitting layer 109. The light scattering fine particles 603 and the dielectric layer 602 can be formed using the material and the manufacturing method described in Embodiment Mode 6.

  Next, the transmissive electrode 105 is formed on the dielectric layer 602. Further, as in Embodiment Mode 4, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated light-emitting layer 159, dielectric layer 652, and transmissive electrode 155 are stacked on the partition layer 115. After the transmissive electrode 105 is formed, the substrate 101 and the substrate 112 are fixed using the sealant 111 and the filler 201 by the process described in the fourth embodiment.

  The light-emitting element according to this embodiment has high light extraction efficiency and can obtain stable light emission. A display device including such a light-emitting element can achieve high luminance and low power consumption.

(Embodiment 9)
This embodiment is shown in FIG. The present embodiment is a display device having a solid sealing structure. In Embodiments 3, 4, 7, and 8, a solid sealing structure provided with a solid obtained by curing a liquid phase material has been described. In this embodiment, the solid sealing structure using the solid which hardened | cured the sheet-like (it is also called film form) sealing material provided on the film base material as solid is shown.

  The substrate 101 formed up to the transmissive electrode 105 is prepared by the process described in Embodiment Mode 1 (FIG. 9A). Further, as in Embodiment Mode 1, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated first dielectric layer 157, light emitting layer 154, second dielectric layer 158, and transmissive electrode 155 are stacked on the partition layer 115.

  In order to fix the substrate 112 to the substrate 101, a sheet-like sealing material 301 is prepared. The uncured sheet-shaped sealing material 301 is made of a resin material having an adhesive function. For the sheet-like sealing material 301, a UV curable resin, a visible light curable resin, or a thermosetting resin can be used. In order to protect the adhesive surface, both surfaces of the sealing material 301 are covered with a film substrate 302. The film base material 302 on one surface of the sheet-like sealing material 301 is peeled off, and the surface is overlapped with the surface of the substrate 101 (FIG. 9B).

  The film base 302 on the other surface is peeled off, and the substrate 112 is overlaid on the substrate 101. While applying pressure to the substrate 101 and the substrate 112, the sheet-like sealing material 301 is cured by irradiating or heating UV light, and the substrate 112 is fixed to the substrate 101. (FIG. 9C).

  By using the sheet-like sealing material 301 in this manner, the substrate 112 can be easily fixed to the substrate 101, and a display device having a solid sealing structure can be formed.

  Note that in the step illustrated in FIG. 9B, the sheet-like sealing material 301 can be provided not on the substrate 101 but on the sealing substrate 112 side. That is, the film base material 302 on one surface of the sheet-like sealing material 301 is peeled off, and the surface is overlapped with the surface of the substrate 112. Then, the film base material 302 on the other surface is peeled off, and the substrate 101 is attached to the substrate 112. You may superimpose.

  The light-emitting element according to this embodiment has high light extraction efficiency, and a display device including such a light-emitting element can achieve high luminance and low power consumption. Further, by using a sheet-like sealing material, the substrates can be easily fixed to each other and the light emitting element can be sealed.

(Embodiment 10)
This embodiment will be described with reference to FIG. This embodiment is a solid sealing structure using a solid obtained by curing a sheet-like sealing material as in the ninth embodiment.

  The substrate 101 formed up to the transmissive electrode 105 is prepared by the process described in Embodiment Mode 2 (FIG. 10A). Further, as in Embodiment Mode 2, an insulating layer 114 and a partition wall layer 115 that cover a part of the reflective electrode 103 are formed over the reflective electrode 103. Note that a separated light-emitting layer 159 and transmissive electrode 155 are stacked over the partition wall layer 115.

  In order to fix the substrate 112 to the substrate 101, a sheet-like sealing material 301 is prepared. The sealing material 301 is the same as that in Embodiment 9, and both surfaces thereof are covered with the film base material 302. Then, by the process described in Embodiment 9, the film base material 302 on one surface of the sheet-like sealing material 301 is peeled off, and the surface is overlapped with the surface of the substrate 101 (FIG. 10B).

  The film base 302 on the other surface is peeled off, and the substrate 112 is overlaid on the substrate 101. The sheet-like sealing material 301 is cured by applying UV light or heating while applying pressure to the substrate 101 and the substrate 112, and the substrate 112 is fixed to the substrate 101 (FIG. 10C).

  By using the sheet-like sealing material 301 in this manner, the substrate 112 can be easily fixed to the substrate 101, and a display device having a solid sealing structure can be formed.

  Note that in the step illustrated in FIG. 10B, the sheet-like sealing material 301 can be provided not on the substrate 101 but on the sealing substrate 112 side. That is, the film base material 302 on one surface of the sheet-like sealing material 301 is peeled off, and the surface is overlapped with the surface of the substrate 112. Then, the film base material 302 on the other surface is peeled off, and the substrate 101 is attached to the substrate 112. You may superimpose.

  The light-emitting element according to this embodiment has high light extraction efficiency, and a display device including such a light-emitting element can achieve high luminance and low power consumption. Further, by using a sheet-like sealing material, the substrates can be easily fixed to each other and the light emitting element can be sealed.

(Embodiment 11)
This embodiment will be described with reference to FIGS. In the present embodiment, an example in which an active matrix EL panel is used as a display device will be described.

  FIG. 11 is a schematic top view of an active matrix EL panel. A sealing substrate 801 is fixed to the substrate 800 with a sealant 802 so that a space between the substrate 800 and the substrate 801 is airtight. In this embodiment, the EL panel sealing structure is a solid sealing structure, and this space is filled with a filler made of resin.

  The substrate 800 is provided with a pixel portion 803, a writing gate signal line driver circuit portion 804, an erasing gate signal line driver circuit portion 805, and a source signal line driver circuit portion 806. The drive circuit units 804 to 806 are each connected to an FPC (flexible printed circuit) 807 that is an external input terminal via a wiring group. The source signal line driver circuit unit 806, the write gate signal line driver circuit unit 804, and the erase gate signal line driver circuit unit 805 respectively receive a video signal, a clock signal, a start signal, and a reset signal from the FPC 807. Receive etc. A printed wiring board (PWB) 808 is attached to the FPC 807.

  Transistors in the pixel portion 803 and the driver circuit portions 804 to 806 are formed of thin film transistors (TFTs). Note that the driver circuit portions 804 to 806 are not necessarily provided on the same substrate 800 as the pixel portion 803 as described above. For example, an IC chip mounted on an FPC on which a wiring pattern is formed ( TCP) or the like may be used and provided outside the substrate. In each of the driver circuit portions 804 to 806, some circuits may be provided on the substrate 800 and some may be provided outside the substrate 800.

  FIG. 12 is a diagram illustrating a circuit for operating one pixel. The pixel portion 803 has a plurality of pixels arranged in a plane. One pixel includes a first transistor 811, a second transistor 812, and a light emitting element 813. Further, a source signal line 814 and a current supply line 815 extending in the column direction, and a gate signal line 816 extending in the row direction are provided. The light-emitting element described in Embodiments 1 to 10 can be applied to the light-emitting element 813. Here, an example in which the light-emitting element having the top-emission structure shown in FIG. That is, an example in which light is extracted from the substrate 801 side is shown.

  Each of the first transistor 811 and the second transistor 812 is a three-terminal element including a gate electrode, a drain region, and a source region, and has a channel formation region between the drain region and the source region. . Here, since the source region and the drain region vary depending on the structure and operating conditions of the transistor, it is difficult to limit which is the source region or the drain region. Therefore, in this specification, the three terminals of the transistor are referred to as a gate electrode, a first electrode, and a second electrode.

  In the writing gate signal line driver circuit portion 804, the gate signal line 816 is electrically connected to the writing gate signal line driver circuit 819 through the switch 818. By controlling the switch 818, the gate signal line 816 is selected to be electrically connected to or disconnected from the writing gate signal line driver circuit 819.

  In the erase gate signal line driver circuit portion 805, the gate signal line 816 is electrically connected to the erase gate signal line driver circuit 821 through the switch 820. By controlling the switch 820, the gate signal line 816 is selected to be electrically connected to or disconnected from the erasing gate signal line driver circuit 821.

  In the source signal line driver circuit portion 806, the source signal line 814 is electrically connected to either the source signal line driver circuit 823 or the power source 824 by the switch 822.

  In the first transistor 811, the gate electrode is electrically connected to the gate signal line 816, the first electrode is electrically connected to the source signal line 814, and the second electrode is electrically connected to the gate electrode of the second transistor 812. Connected.

  As described above, the second transistor 812 has the gate electrode electrically connected to the second electrode of the first transistor, the first electrode electrically connected to the current supply line 815, and the second electrode serving as the light emitting element. 813 is electrically connected to the first electrode. The second electrode of the light emitting element 813 has a constant potential.

  The structure of the pixel of this embodiment will be described with reference to FIG. In this embodiment, since the EL panel has a solid sealing structure, an airtight space between the substrate 800 and the sealing substrate 801 is filled with a filler 830 made of resin. A structure 831 and a light-emitting element 813 are formed over the substrate 800. As the structure 831, the first transistor 811 and the second transistor 812 illustrated in FIG. 12 are formed over the base film 832. An interlayer insulating film 833 is formed over the first transistor 811 and the second transistor 812, and a light-emitting element 813 and an insulating layer 834 functioning as a partition are formed over the interlayer insulating film 833.

  The first transistor 811 and the second transistor 812 are top-gate thin film transistors in which a gate electrode is provided on the side opposite to the substrate 800 with a semiconductor layer in which a channel formation region is formed as a center. The thin film transistor structures of the first transistor 811 and the second transistor 812 are not particularly limited, and may be, for example, a bottom gate type. In the case of a bottom gate, the semiconductor layer forming a channel may be formed with a protective film (channel protection type), or the semiconductor layer forming the channel may be partially concave ( Channel etch type).

  The semiconductor layer in which the channel formation regions of the first transistor 811 and the second transistor 812 are formed may be either a crystalline semiconductor or an amorphous semiconductor.

  Specific examples of the crystalline semiconductor of the semiconductor layer include those made of single crystal or polycrystalline silicon, silicon germanium, or the like. These may be formed by laser crystallization, or may be formed by crystallization by a solid phase growth method using nickel or the like, for example.

  In the case where the semiconductor layer is formed using an amorphous semiconductor, for example, amorphous silicon, it is preferable that all the transistors included in the pixel portion 803 be N-channel thin film transistors. Other than that, the pixel portion 803 may be formed of one of an N-channel transistor and a P-channel transistor, or may be formed of both transistors.

  Further, the variety of structures of the transistors used in the driver circuit portions 804 to 806 is similar to that of the first transistor 811 and the second transistor 812 in the pixel portion 803. As for the driver circuit portions 804 to 806, all of them may be constituted by thin film transistors in accordance with the performance of the transistors, or a part of the circuit may be constituted by thin film transistors and the rest may be constituted by IC chips. In addition, all of the transistors in the driver circuit portions 804 to 806 may be configured by any one of N-channel and P-channel transistors, or may be configured by both transistors.

  FIG. 13 illustrates an example in which the light-emitting element 120 illustrated in FIG. 1A of Embodiment 1 is applied as the light-emitting element 813. The light-emitting element 813 includes a light-emitting layer 837 between the first electrode 835 and the second electrode 836. In addition, the first dielectric layer 826 is provided between the first electrode 835 and the light emitting layer 837, and the light scattering fine particles 827 are dispersed between the light emitting layer 837 and the second electrode 836. A dielectric layer 828 is provided. The first electrode 835 is a reflective electrode and functions as a cathode. The second electrode 836 is a light-transmitting electrode and functions as an anode. Light generated in the light-emitting layer 837 is extracted from the second electrode 836. Here, the first electrode 835, the first dielectric layer 826, the light emitting layer 837, the second dielectric layer 828 in which the light scattering fine particles 827 are dispersed, and the second electrode 836 are formed in this order on the interlayer insulating film 833. The structure is formed by stacking. In this embodiment, the amount of light totally incident on the interface between the second dielectric layer 828 and the second electrode 836 is reduced by the light scattering fine particles 827 dispersed in the second dielectric layer 828. The light extraction efficiency of the light-emitting element 813 can be improved.

  The first electrode 835 is the reflective electrode 103, the first dielectric layer 826 is the first dielectric layer 107, the light emitting layer 837 is the light emitting layer 104, and the second dielectric layer in which the light scattering particles 827 are dispersed. Reference numeral 828 corresponds to the second dielectric layer 108 in which the light scattering fine particles 106 are dispersed, and the second electrode 836 corresponds to the transmissive electrode 105. Needless to say, the structure of the light-emitting element of this embodiment is not particularly limited, and light-emitting elements of other embodiments can be applied. The light emitting element 813 includes at least a light emitting layer sandwiched between a pair of electrodes and a dielectric layer in which light scattering fine particles are dispersed, or a light emitting layer in which light scattering fine particles and a particulate light emitting material are sandwiched between a pair of electrodes. Any configuration that has

  The first electrode 835 is connected to the second electrode of the second transistor 812 through a contact hole provided in the interlayer insulating film 833.

  In the present embodiment, the solid sealing structure shown in the third embodiment is applied as the EL panel sealing structure, but it goes without saying that the sealing structures of other embodiments can be applied. Further, although the top emission light-emitting element 813 is applied, the position of the first electrode 835 that is a reflective electrode and the position of the second electrode 836 that is a light-transmitting electrode and the first dielectric layer A light-emitting element having a bottom emission structure in which the position of the second dielectric layer 828 in which 826 and the light-scattering fine particles 827 are dispersed may be reversed.

  A method for driving the EL panel of this embodiment will be described with reference to FIG. FIG. 14 is a diagram for explaining the operation of a frame over time. In FIG. 14, the horizontal axis represents the passage of time, and the vertical axis represents the number of scanning stages of the gate signal line.

  When image display is performed using the EL panel of this embodiment, the screen rewriting operation and the display operation are repeatedly performed during the display period. There is no particular limitation on the number of times of rewriting, but it is preferable that the number of rewritings is at least about 60 times per second so that a person viewing the image does not feel flicker (also referred to as flicker). Here, a period during which one screen (one frame) is rewritten and displayed is referred to as one frame period.

As shown in FIG. 14, one frame includes four subframes 841 including a write period 841a, a write period 842a, a write period 843a, a write period 844a and a holding period 841b, a holding period 842b, a holding period 843b, and a holding period 844b. , Subframe 842, subframe 843, and subframe 844. A light emitting element to which a signal for emitting light is given is in a light emitting state in the holding period. The ratio of the length of the retention period in each subframe is as follows: first subframe 841: second subframe 842: third subframe 843: fourth subframe 844 = 2 ³ : 2 ² : 2 ¹ : 2 ⁰ = 8: 4: 2: 1. As a result, 4-bit gradation can be expressed. However, the number of bits and the number of gradations are not limited to those described here. For example, eight subframes may be provided so that 8-bit gradation can be performed.

  An operation in one frame will be described. First, in the subframe 841, write operations are performed in order from the first row to the last row. Therefore, the start time of the writing period differs depending on the row. From the row in which the writing period 841a is completed, the holding period 841b is shifted in order. In the holding period, the light-emitting element to which a signal for emitting light is given is in a light-emitting state. Further, the processing proceeds to the next subframe 842 in order from the row in which the holding period 841b ends, and the writing operation is performed in order from the first row to the last row as in the case of the subframe 841.

  The above operation is repeated, and the holding period 844b of the subframe 844 is ended. When the operation in the subframe 844 is completed, the process proceeds to the next frame. Thus, the accumulated time of the light emission in each subframe is the light emission time of each light emitting element in one frame. By combining pixels with different light emission times, various display colors having different brightness and chromaticity can be formed.

  When it is desired to forcibly end the holding period in the row that has already been written and shifted to the holding period before the writing up to the last row is finished as in the subframe 844, the erasing period is after the holding period 844b. It is preferable to provide 844c and control so that the light emission is forcibly stopped. A row that is forcibly set to the non-light-emitting state is kept in the non-light-emitting state for a certain period (this period is referred to as a non-light-emitting period 844d). Then, as soon as the writing period of the last row is completed, the writing sequence of the next subframe (or frame) is started in order from the first row. Accordingly, it is possible to prevent the writing period of the subframe 844 from overlapping with the writing period of the next subframe.

  In this embodiment, the subframe 841 to the subframe 844 are arranged in order from the one with the long retention period. However, the subframe 841 to the subframe 844 are not necessarily arranged as in the present embodiment. Alternatively, a long holding period and a short holding period may be arranged at random. In addition, the subframe may be further divided into a plurality of frames. That is, the gate signal line may be scanned a plurality of times during the period when the same video signal is applied.

  The operation of the circuit shown in FIG. 12 in the writing period and the erasing period will be described. First, the operation in the writing period will be described. In the writing period, the gate signal line 816 in the n-th row (n is a natural number) is electrically connected to the writing gate signal line driving circuit 819 by the switch 818. On the other hand, the erasing gate signal line driving circuit 821 is disconnected by the switch 820.

  The source signal line 814 is electrically connected to the source signal line driver circuit 823 through the switch 822. Here, a signal is input to the gate of the first transistor 811 connected to the gate signal line 816 in the n-th row (n is a natural number), and the first transistor 811 is turned on. At this time, video signals are simultaneously input to the source signal lines 814 from the first column to the last column. Note that the video signals input to the source signal lines 814 in each column are independent from each other.

  The video signal input to the source signal line 814 is input to the gate electrode of the second transistor 812 through the first transistor 811 connected to each source signal line 814. Then, depending on the current value, the light emitting element 813 determines light emission or non-light emission. For example, in the case where the second transistor 812 is a P-channel transistor, the light emitting element 813 emits light when a Low Level signal is input to the gate electrode of the second transistor 812. On the other hand, in the case where the second transistor 812 is an n-channel transistor, a high level signal is input to the gate electrode of the second transistor 812 so that a current flows through the light-emitting element 813 and the light-emitting element 813 emits light. .

  Next, the operation in the erasing period will be described. In the erasing period, the gate signal line 816 in the n-th row (n is a natural number) is electrically connected to the erasing gate signal line driving circuit 821 through the switch 820. On the other hand, the write gate signal line drive circuit 819 and the switch 818 are disconnected. The source signal line 814 is electrically connected to the power source 824 by the switch 822. A signal is input to the gate of the first transistor 811 connected to the gate signal line 816 in the n-th row, and the first transistor 811 is turned on. At this time, the erase signal is simultaneously input to the source signal lines 814 from the first column to the last column.

  The erase signal input to the source signal line 814 is input to the gate electrode of the second transistor 812 through the first transistor 811 connected to each source signal line 814. A signal input to the second transistor 812 blocks current supply from the current supply line 815 to the light-emitting element 813, and the light-emitting element 813 is forcibly turned off. For example, in the case where the second transistor 812 is a p-channel transistor, the light-emitting element 813 does not emit light when a high level signal is input to the gate electrode of the second transistor 812. On the other hand, in the case where the second transistor 812 is an n-channel transistor, a light level signal is input to the gate electrode of the second transistor 812 so that the light-emitting element 813 does not emit light.

  In the erasing period, for the nth row (n is a natural number), a signal for erasing is input by the operation as described above. However, as described above, the nth row may be an erasing period and the other row (mth row (m is a natural number)) may be a writing period. In such a case, it is necessary to input a signal for erasure to the n-th row and a signal for writing to the m-th row using the source signal line 814 of the same column. It is preferable to operate as described above.

  The gate signal line 816 and the erasing gate signal line driver circuit 821 are immediately disconnected after the light emitting element 813 in the nth row does not emit light by the operation in the erasing period described above. The source signal line 814 and the source signal line driver circuit 823 are connected by switching the switch 822. Then, the gate signal line 816 and the write gate signal line driver circuit 819 are connected by the switch 818. Then, a signal is selectively input from the writing gate signal line driver circuit 819 to the gate signal line 816 in the m-th row, the first transistor 811 is turned on, and the source signal line driver circuit 823 receives one column. A signal for writing is input to the source signal line 814 from the first to the last column. By this signal, the m-th row light emitting element emits light or does not emit light.

  Immediately after the writing period for the m-th row is completed as described above, the erasing period for the (n + 1) -th row is started. Therefore, the switch 818 disconnects the gate signal line 816 and the write gate signal line drive circuit 819 and connects the erase gate signal line drive circuit 821 with the switch 820. In addition, the source signal line 814 is connected to the power source 824 by switching the switch 822. A signal is input from the erasing gate signal line driver circuit 821 to the gate signal line 816 of the (n + 1) th row to turn on the first transistor 811 and an erasing signal is input from the power source 824. In this way, when the erasing period of the (n + 1) th row is finished, the writing period immediately shifts to the mth row. Thereafter, similarly, the erasing period and the writing period may be repeated until the erasing period of the last row is operated.

  Note that although an active matrix EL panel has been described in this embodiment, the display devices of Embodiments 1 to 10 can be applied to a passive matrix EL panel. For example, FIG. 17A shows an example of a perspective view of a passive matrix EL panel manufactured by applying the present invention. FIG. 17B illustrates an example of a cross-sectional view taken along dashed line XY in FIG.

  17A and 17B, an electrode 952, a layer 955, and an electrode 956 are sequentially stacked over a substrate 951. One of the electrode 952 and the electrode 956 is an electrode having reflectivity, and the other is an electrode having translucency. The layer 955 includes at least the light-emitting layer described in Embodiments 1, 3, 5, 7, and 9, and the dielectric layer in which the light scattering fine particles are dispersed, or the particles described in Embodiments 2, 4, 6, 8, and 10. And a light emitting layer in which light-emitting material and light scattering fine particles are dispersed. Note that the dielectric layer in which the light scattering fine particles are dispersed or the light emitting layer in which the light scattering fine particles are dispersed is provided in contact with the light-transmitting electrode. With this configuration, the amount of light that is incident on the interface between the dielectric layer or the light emitting layer and the light-transmitting electrode is totally reflected by the light scattering fine particles dispersed in the dielectric layer or the light emitting layer. Therefore, the light extraction efficiency of the light emitting element can be improved.

  Further, an end portion and a part of the electrode 952 are covered with an insulating layer 953. The insulating layer 953 has a plurality of openings, and in the openings, an electrode 952, a layer 955, and an electrode 956 are sequentially stacked. A partition layer 954 is provided over a region where the opening of the insulating layer 953 is not formed. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (the side facing the insulating layer 953 in the same direction as the surface direction of the insulating layer 953) is the top side (the surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, the electrode 956 can be insulated from an adjacent electrode.

(Embodiment 12)
The display devices described in Embodiments 1 to 10 can achieve higher luminance and lower power consumption by improving light extraction efficiency of the light-emitting elements. Therefore, by mounting these display devices as a display portion, a bright and bright display can be achieved with low power consumption.

  The display devices of Embodiments 1 to 10 can be preferably used for a display unit of a battery-driven electronic device, a large-screen display device, or a display unit of an electronic device. For example, the sound of a television device (television, television receiver), digital camera, digital video camera, mobile phone device (mobile phone), PDA or other portable information terminal, portable game machine, monitor, computer, car audio, etc. Examples thereof include an image reproducing device provided with a recording medium such as a reproducing device and a home game machine. A specific example thereof will be described with reference to FIG. The display device used for the display unit may have either an active matrix type or a passive matrix type structure.

  The display device of the present invention is used for the display portion 911 of the portable information terminal device shown in FIG.

  The display device of the present invention is used for the finder 914 of the digital video camera shown in FIG. 15B and the display portion 913 for displaying the captured video.

  The display device of the present invention can be applied to the display portion 915 of the cellular phone illustrated in FIG.

  The display device of the above embodiment is used for the display portion 916 of the portable television device illustrated in FIG. In addition, as a television device, a wide variety of television devices ranging from a small one mounted on a portable terminal such as a cellular phone to a medium-sized one that can be carried and a large one (for example, 40 inches or more). A display device is used for the display unit.

  The display device of the present invention can be applied to the display portion 917 of the laptop computer or laptop computer shown in FIG.

  The display device of the present invention can be applied to the display portion 918 of the television device illustrated in FIG. As a television device, a small-sized device mounted on a portable terminal such as a cellular phone shown in FIG. 15C, a medium-sized device that can be carried, or a large-sized device (for example, 40 inches or more). The display device of the above embodiment can be applied to the display units of a wide variety of television devices.

  In the electronic device according to this embodiment, high luminance and low power consumption can be realized by using the light-emitting element of the present invention and a display device including the light-emitting element in the display portion.

(Embodiment 13)
In the present embodiment, a mode in which the display device is applied to a planar lighting device will be described. The display devices of Embodiments 1 to 10 can be used as a planar lighting device in addition to the display unit. For example, when a liquid crystal panel is used for the display portion of the electronic device exemplified in this embodiment, the display device of the above embodiment can be mounted as a backlight of the liquid crystal panel. When used as a lighting device, a passive matrix display device as shown in FIG. 17 is preferable.

  FIG. 16 illustrates an example of a liquid crystal display device using the display device as a backlight. The liquid crystal display device illustrated in FIG. 16 includes a housing 921, a liquid crystal layer 922, a backlight 923, and a housing 924, and the liquid crystal layer 922 is connected to a driver IC 925. The backlight 923 uses the display device of the present invention, and a current is supplied from a terminal 926.

  In addition, the liquid crystal display device including the backlight according to the present embodiment can be used as a display unit of various electronic devices as described in the twelfth embodiment.

  By using a display device to which the present invention is applied, a bright and low power consumption backlight can be obtained. In addition, the display device to which the present invention is applied is a surface emitting lighting device and can have a large area, so that a backlight can have a large area and a liquid crystal display device can have a large area. Further, since the display device is thin and has low power consumption, the display device can be thinned and reduced in power consumption.

Sectional view of display device (Embodiment 1) Sectional view of display device (Embodiment 2) Sectional view of display device (Embodiment 3) Sectional view of display device (Embodiment 4) Sectional view of display device (Embodiment 5) Sectional view of display device (Embodiment 6) Sectional view of display device (Embodiment 7) Sectional view of display device (Embodiment 8) Sectional view of display device (Embodiment 9) Sectional view of display device (Embodiment 10) Front view of display device (Embodiment 11) FIG. 11 illustrates a pixel circuit of a display device (Embodiment 11). Sectional view of a pixel of a display device (Embodiment 11) FIG. 11 illustrates a driving method of a display device (Embodiment 11). FIG. 12 illustrates a mode in which a display device is applied to an electronic device (Embodiment 12). FIG. 13 illustrates a mode in which a display device is applied to a planar lighting device (Embodiment 13). A perspective view and a cross-sectional view of a display device (Embodiment 11)

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Substrate 103 Reflective electrode 104 Light emitting layer 105 Transmission electrode 106 Light scattering fine particle 107 First dielectric layer 108 Second dielectric layer 109 Light emitting layer 110 Particulate light emitting material 111 Sealing material 112 Substrate 113 Gas 114 Insulating layer 115 Partition wall Layer 153 reflective electrode 154 light emitting layer 155 transmissive electrode 157 first dielectric layer 158 second dielectric layer 159 light emitting layer 120 light emitting element 130 light emitting element 201 filler 202 third dielectric layer 203 light scattering fine particles 252 third Dielectric layer 301 Sealing material 302 Film substrate 602 Dielectric layer 603 Light scattering fine particle 652 Dielectric layer 800 Substrate 801 Substrate 802 Sealing material 803 Pixel portion 804 Driving circuit portion 805 Driving circuit portion 806 Driving circuit portion 807 FPC
808 Printed wiring board (PWB)
811 1st transistor 812 2nd transistor 813 Light emitting element 814 Source signal line 815 Current supply line 816 Gate signal line 818 Switch 819 Write gate signal line drive circuit 820 Switch 821 Erase gate signal line drive circuit 822 Switch 823 Source Signal line driver circuit 824 Power source 826 First dielectric layer 827 Light scattering fine particle 828 Second dielectric layer 830 Filler 831 Structure 832 Base film 833 Interlayer insulating film 834 Insulating layer 835 First electrode 836 Second electrode 837 Light emitting layer 841 Subframe 842 Subframe 843 Subframe 844 Subframe 911 Display unit 913 Display unit 914 Finder 915 Display unit 916 Display unit 917 Display unit 918 Display unit 921 Case 922 Liquid crystal layer 923 Backlight 924 Case 925 Liver IC
926 Terminal 951 Substrate 952 Electrode 953 Insulating layer 954 Partition layer 955 Layer 956 Electrode 841a Period 841b Holding period 842a Period 842b Holding period 843a Period 843b Holding period 844a Period 844b Holding period 844c Erasing period 844d Non-light emitting period

Claims (10)

A first electrode;
A second electrode;
A light emitting layer between the first electrode and the second electrode;
A dielectric layer between the first electrode and the light emitting layer;
Have
The dielectric layer has light scattering particles dispersed therein,
The light-emitting element, wherein light emitted from the light-emitting layer is extracted from the first electrode. A first electrode;
A second electrode;
A light emitting layer between the first electrode and the second electrode;
The light emitting layer includes a binder, a particulate light emitting material, and light scattering fine particles, and the particulate light emitting material and the light scattering fine particles are dispersed in the binder,
The light-emitting element, wherein light emitted from the light-emitting layer is extracted from the first electrode. In claim 1 or claim 2,
The light-scattering fine particles are made of an organic material or an inorganic material, and are light-emitting elements having a particle diameter of 2 nm to 100 nm. In any one of Claim 1 thru | or 3,
The light-emitting element, wherein the first electrode is a light-transmitting electrode. A first substrate;
A second substrate;
Between the first substrate and the second substrate, a light emitting element, and a sealing material provided for sealing the light emitting element,
Have
The light emitting element includes a light emitting layer between a first electrode and a second electrode,
A dielectric layer between the first electrode and the light emitting layer;
The dielectric layer has light scattering particles dispersed therein,
The light emitted from the light emitting layer is extracted from the first substrate through the first electrode. A first substrate;
A second substrate;
Between the first substrate and the second substrate, a light emitting element, and a sealing material provided for sealing the light emitting element,
Have
The light emitting element includes a light emitting layer between a first electrode and a second electrode,
The light emitting layer includes a binder, a particulate light emitting material, and light scattering fine particles, and the particulate light emitting material and the light scattering fine particles are dispersed in the binder,
The light emitted from the light emitting layer is extracted from the first substrate through the first electrode. In claim 5 or claim 6,
The display device, wherein the light scattering fine particles are made of an organic material or an inorganic material and have a particle diameter of 2 nm to 100 nm. In any one of Claims 5 thru | or 7,
The first electrode is a light-transmitting electrode;
The display device, wherein the first substrate is a substrate having a transmittance of 80% or more with respect to visible light. In any one of Claims 5 thru | or 8,
The sealing material is provided in the periphery of the first substrate and the second substrate,
A display device, wherein a gas is filled between the first substrate, the second substrate, and the first substrate and the second substrate which are hermetically sealed by the sealant. In any one of Claims 5 thru | or 8,
The sealing material is provided in the periphery of the first substrate and the second substrate,
A display device, wherein a resin is provided between the first substrate, the second substrate, and the first substrate and the second substrate that are hermetically sealed by the sealant.

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