JP2008016348A - Organic electroluminescent element and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element and display device in which an existing color filter for a liquid crystal display can be used as it is and which provides high light extraction efficiency. <P>SOLUTION: The organic electroluminescent element is provided with at least one or more organic light emitting layers having a light emitting region, a positive electrode for injecting a positive hole in the organic light emitting layer, and a negative electrode for injecting an electron formed on a substrate. A first base layer, a second base layer, a color filter layer, and a third base layer are provided in this order from a substrate side on the substrate. When refractive indexes of the first base layer, second base layer, third base layer are respectively n1, n2, n3 in a wavelength of light extracted by the color filter out of the light emitted by the organic light emitting layer, n1<n2, and n2<n3, and fine particles having a refractive index different from the refractive indexes of the respective base layers in the wavelength of the light extracted by the color filter are dispersed on the second base layer and third base layer. The display element is provided with such the organic electroluminescent element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a color filter for the color of light emitted from an organic light emitting layer among organic electroluminescent elements that extract light from the organic light emitting layer by injecting electrons and holes into the organic light emitting layer sandwiched between the cathode and the anode. The present invention relates to a dot-matrix organic electroluminescent element having a function of changing by using and a display device including the organic electroluminescent element.

  An organic electroluminescent element is a light emitting element having a structure in which an organic light emitting layer is sandwiched between an anode and a cathode. When a voltage is applied, holes are injected from the anode, and electrons are injected from the cathode. It is an element that takes out the energy generated by recombination on or inside the organic light emitting layer as light. Organic electroluminescence devices using organic substances in the light emitting layer have been studied for a long time, but their practical application has not progressed due to the problem of light emission efficiency. In contrast, in 1987, C.I. W. Tang proposed an organic electroluminescence device with a laminated structure in which the organic layer is divided into a light emitting layer and a hole transport layer, and confirmed high-efficiency light emission at a low voltage (see Non-Patent Document 1, etc.) and thereafter. Researches on organic electroluminescence devices have been actively conducted. By adopting such a laminated structure, it is possible to prevent electrons and holes injected into the light emitting layer from flowing to the counter electrode, and the recombination efficiency in the light emitting layer is improved. Further, the efficiency of injecting electrons and holes into the light emitting layer can be increased. Therefore, at present, organic electroluminescence elements generally have a laminated structure, and the structure is a two-layer structure of a light emitting layer and a hole injection layer, a three-layer structure of an electron injection layer and a light emitting layer, a hole injection layer, Devices having a structure such as a four-layer structure of an electron injection layer, a light emitting layer, a hole transport layer, and a hole injection layer have been proposed.

  However, it is known that in the organic electroluminescence device, the probability of singlet generation necessary for emitting fluorescence upon recombination in the light emitting layer is statistically 25%. Therefore, theoretically, only 1/4 of the injected electrons and holes can be extracted as light. On the other hand, an organic electroluminescence element using phosphorescence from an excited triplet has been proposed (see Non-Patent Document 2, etc.), and in recent years, materials that exhibit phosphorescence at room temperature have been actively studied.

  Nevertheless, the refractive index of the material used for the organic layer is relatively high, and light is emitted isotropically in three dimensions inside the organic light emitting layer, so that all the light generated at an angle greater than the critical angle with respect to the substrate surface is generated. Reflection occurs and light below the critical angle is partially reflected at the interface and cannot be extracted outside. For this reason, when the refractive index of the light emitting layer is 1.6, only about 20% of the generated light can be extracted to the outside, and this value is further lowered when the refractive index of the light emitting layer is high.

  Various proposals have been made as methods for improving the light extraction efficiency. Among them, as a technique for improving the light extraction efficiency by a relatively easy technique, several techniques for changing the traveling direction of light at the substrate portion have been proposed. For example, Patent Document 1 and Patent Document 2 have proposed that a scattering layer is provided outside the substrate. In Patent Document 3, the substrate itself has a scattering property. Further, in Patent Document 4, a lens structure is provided on the substrate surface. However, these structures are effective means for light reaching the substrate and do not affect the extraction efficiency of light incident on the substrate from the light emitting layer. Furthermore, it is effective when an organic electroluminescence element is used as a surface light source, but an equal matrix element is not an effective means in consideration of parallax so as to require a color filter.

  Further, Patent Document 5 proposes an organic electroluminescence element characterized in that a layer having a refractive index equal to or greater than that of the light emitting layer and having a scattering property is provided between the substrate and the light extraction surface. In this case, the light extraction efficiency to the substrate is improved, but there is a problem of the critical angle between the substrate and the outside world, so that the light extraction efficiency is improved for light exceeding the critical angle to the outside world while reaching the substrate. I can't let you. In this case, the light extraction efficiency can be improved by taking a structure such as scattering or diffraction on the inside or outside surface of the substrate, but in this case as well, pixels having different emission colors are formed on the substrate like the dot matrix display as described above. It will not be an effective means with the element.

  On the other hand, when creating a full-color display device using a dot matrix organic electroluminescence element, one pixel is further divided into a plurality of sub-pixels, each sub-pixel having a different emission color, and the intensity of light is changed for each sub-pixel. The color tone of the pixel is created by additive color mixture of light. In this case, in order to emit light of different colors for each subpixel, it is necessary to change the element structure for each subpixel. In general, a widely used method is a method of patterning different organic light-emitting layers on a substrate in accordance with the shape of the subpixel by changing the material type of the organic light-emitting layer that emits light for each subpixel. When the organic light emitting layer is a low molecular weight material and a thin film of the organic light emitting layer is formed by vacuum deposition, patterning of the light emitting layer is obtained by depositing a metal mask with a hole corresponding to the shape of the subpixel on the substrate. ing. If the organic light-emitting layer is a polymer material, the material is dissolved in a solvent, and a thin film of the organic light-emitting layer is formed by a coating method, a pattern corresponding to the shape of the subpixel is formed in advance and then patterned by inkjet. Or a method of forming a pattern by screen printing, gravure printing, or the like.

  However, in the case of the vacuum deposition method using a metal mask, when the substrate is enlarged, the mask itself is distorted by the weight of the mask itself or the radiant heat from the deposition source of the organic light emitting layer, and the pattern is displaced. Occurs. Further, even when the ink jet method is used with a polymer material, when the substrate is enlarged, the drawing time becomes long and the production efficiency is deteriorated. On the other hand, even in the case of screen printing or gravure printing, in terms of plate accuracy, pattern displacement becomes a problem when the substrate is enlarged or the pixels are high definition. In addition, methods have been proposed in which the material of the organic light-emitting layer itself is made reactive, or a photoresist layer is formed on the organic light-emitting layer and patterned by a photolithography method. There is a problem that the organic light emitting layer is damaged in the etching process, and the performance of the device is greatly deteriorated.

  In contrast, if the organic light-emitting layer is formed with a solid surface all over the surface of the substrate and the color of the sub-pixel is created by the color filter on the substrate, the pattern shifts due to the increase in the size and resolution of the substrate. The problem is much less. In the case of this method, since the light of the organic light emitting layer serving as the light source is cut by the color filter, there is a problem that the light use efficiency is lowered. However, in the case of a dot matrix element produced by patterning an organic light emitting layer for each subpixel, when the pixel is not lit, external light is reflected on the back electrode and a metallic luster can be seen. In addition, a circularly polarizing plate is disposed outside the device. For this reason, half of the light generated in the element and extracted to the outside is cut by the circularly polarizing plate. On the other hand, when the substrate has a color filter, external light is reflected by the back electrode of the element and passes through the color filter layer twice before returning to the outside. For this reason, external light is almost absorbed by the color filter, and the color of the pixel when not lit appears substantially black, so a circularly polarizing plate is not required. For this reason, considering the absorption by the color filter and the absorption by the circularly polarizing plate, it can be considered that there is not much difference in the light utilization efficiency between the two element structures.

In view of such a problem, the present inventor in JP-A No. 2004-133867 improves the light extraction efficiency of an organic electroluminescence element using a color filter by increasing the refractive index of the resin of the color filter and adding a scattering function. Showed that it is possible. However, this method is effective for improving the light extraction efficiency from the device, but on the other hand, it becomes impossible to use the resin used for the color filter that has been developed so far for liquid crystal display applications. For this reason, it is necessary to develop a color filter based on a new resin separately from the color filter resist developed for liquid crystal display applications.
C. W. Tang, S.M. A. VanSlyke, Applied Physics Letters, 51, 913, 1987 M.M. A. Baldo et al. , Nature, 395, 151, 1998 JP 2003-109747 A JP 2002-75657 A JP 2001-356207 A JP-A-8-83688 JP 2004-296429 A Japanese Patent Application No. 2006-90980

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a high-light-extraction efficiency dot-matrix organic electroluminescent device that can use an existing liquid crystal display color filter as it is, and such an organic electroluminescent device. An object of the present invention is to provide a display device including an element.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, this invention provides the organic electroluminescent element shown by following (1)-(16), and the display apparatus shown by following (17).

(1)
An organic electroluminescent device comprising at least one organic light emitting layer having a light emitting region on a substrate, an anode for injecting holes into the organic light emitting layer, and a cathode for injecting electrons. Includes a first underlayer, a second underlayer, a color filter layer, and a third underlayer in this order from the substrate side, and out of the light emitted by the organic light emitting layer at the wavelength of the light extracted by the color filter. When the refractive indexes of the first base layer, the second base layer, and the third base layer are n1, n2, and n3, respectively, n1 <n2 and n2 <n3, and the second base layer and the third base layer The organic electroluminescence device is characterized in that fine particles having a refractive index different from the refractive index of each underlying layer are dispersed at the wavelength of light extracted by the color filter. .

(2)
Of the light emitted from the organic light emitting layer, the refractive index of the first underlayer at the wavelength of the light extracted by the color filter is smaller than the refractive index of the substrate and 1.4 or less. The organic electroluminescent element as described in said (1).

(3)
Of the light emitted by the organic light emitting layer, the refractive index of the first underlayer at the wavelength of the light extracted by the color filter is 1.3 or less. Electroluminescence element.

(4)
Of the light emitted from the organic light emitting layer, the third underlayer has a refractive index of 1.7 or more at a wavelength of light extracted by the color filter. (1) to (3) Organic electroluminescent element of any one of these.

(5)
Of the light emitted from the organic light emitting layer, the refractive index of the third underlayer at the wavelength of the light extracted by the color filter is 1.8 or more. Luminescence element.

(6)
A smoothing layer is further provided on the third underlayer, and a refractive index of the smoothing layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.7 or more. The organic electroluminescence device according to any one of the above (1) to (5), wherein:

(7)
The organic electroluminescence according to (6) above, wherein a refractive index of the smoothing layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.8 or more. element.

(8)
A gas barrier layer is further provided on the smoothing layer, and a refractive index of the gas barrier layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.7 or more. The organic electroluminescent element according to any one of (1) to (7) above.

(9)
The organic electroluminescent device according to (8) above, wherein a refractive index of the gas barrier layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.8 or more. .

(10)
The difference between the refractive index of the second base layer and the refractive index of the color filter layer at a wavelength of light extracted by the color filter out of the light emitted from the organic light emitting layer is 0.1 or less. The organic electroluminescence device according to any one of (1) to (9) above.

(11)
The difference between the refractive index of the second base layer and the refractive index of the color filter layer at the wavelength of the light extracted by the color filter out of the light emitted from the organic light emitting layer is 0.05 or less. The organic electroluminescence device according to (10) above.

(12)
The organic electroluminescence device according to any one of (1) to (11), wherein the fine particles are made of a metal, a metal compound, a silicon compound, a resin, or a mixture thereof.

(13)
The organic electroluminescent device as described in (12) above, wherein the metal compound is an oxide or nitride of titanium, zirconium, aluminum, or cerium.

(14)
The organic electroluminescence element according to any one of (1) to (13), wherein the first underlayer includes porous silica.

(15)
The organic electroluminescent element according to any one of (1) to (13), wherein the first underlayer includes a resin having fluorine.

(16)
The organic electroluminescence element according to any one of (1) to (13), wherein the first underlayer includes a fluoride salt.

(17)
The display apparatus provided with the organic electroluminescent element of any one of said (1) thru | or (16).

  According to the present invention, there is provided an organic electroluminescent device comprising one or more organic light emitting layers having a light emitting region, an anode for injecting holes into the organic light emitting layer, and a cathode for injecting electrons, The substrate is formed from the substrate side in the order of the first underlayer, the second underlayer, the color filter layer, and the third underlayer. The second underlayer and the third underlayer are provided with scattering properties, and the refractive index of each layer. By optimizing as described above, it is possible to provide an organic electroluminescent element excellent in light extraction efficiency and a display device using the same.

  Several embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or similar components are denoted by the same reference numerals.

  FIG. 1 is a schematic cross-sectional view showing an organic electroluminescence element 100 according to the first embodiment of the present invention. The organic electroluminescent element 100 includes a first base layer 102, a second base layer 103, a color filter layer 104, and a third base layer 105 in this order from the substrate side on a substrate 101, and further two electrodes on the first base layer 102, the second base layer 103, the color filter layer 104, and the third base layer 105. An organic light emitting layer 107 sandwiched between 106 and 108 is disposed. Of the light emitted from the organic light emitting layer 107, the refractive indices of the first ground layer 102, the second ground layer 103, the color filter layer 104, and the third ground layer 105 at the wavelength of the light transmitted by the color filter layer 104 are n1. , N2, nc, and n3, n1 <n2 and n2 <n3, and the second underlayer 103 and the third underlayer 105 have respective underlayers at the wavelength of light extracted by the color filter 104. Fine particles having a refractive index different from that of the above are dispersed. In addition, the wavelength of the light which the color filter layer 104 permeate | transmits among the light which the organic light emitting layer 106 discharge | releases exists in the range of 420 nm-750 nm as a peak wavelength normally as a peak wavelength.

  The light generated in the organic light emitting layer 107 passes through the substrate-side electrode 106 (usually a transparent electrode). In this case, the refractive index of the normally transparent electrode 106 is higher than the refractive index of the organic light emitting layer. There are no horns. Further, when light passes through the electrode 106 and enters the third underlayer 105, the light that reaches the interface between the electrode 106 and the third underlayer 105 is refracted according to Snell's law, and is at an angle greater than the critical angle. The light that reaches the interface causes total reflection and cannot enter the third underlayer 105. In general, since the electrode 106 needs to be light transmissive, an ITO (indium tin oxide) film or an IZO (indium zinc oxide) film is used for the electrode, and its refractive index is 1.8 to It is about 2.0. Therefore, in order to increase the critical angle and reduce the total reflected light, the refractive index n3 of the third underlayer 105 should be large, preferably 1.7 or more, more preferably 1.8 or more. The refractive index n3 of the third underlayer 105 is usually 2.5 or less.

  Further, light enters the color filter layer 104 from the third base layer 105. The third base layer 105 has a refractive index different from the refractive index n3 of the third base layer 105 at the wavelength of light extracted by the color filter layer 104. Since the fine particles having a rate are dispersed, when the incident light enters the third underlayer 105, the fine particles contained in the layer cause scattering. On the other hand, since the resin used for the color filter is often an acrylic resin in the case of liquid crystal, the refractive index nc of the color filter layer is about 1.45 to 1.6. For this reason, a critical angle exists when light enters the color filter layer 104 from the third underlayer 105. However, since light is scattered in the third underlayer 105, the first angle is greater than the critical angle. Light that enters the color filter layer 104 from the third underlayer 105, undergoes total reflection at the interface between the third underlayer 105 and the color filter layer 104, and returns to the third underlayer 105 is scattered inside the third underlayer 105. Is caused to change the traveling direction of the light and enter the color filter layer 104 again at a different angle. For this reason, since the angle of light incident at an angle greater than the critical angle changes every time scattering occurs, the light can enter the color filter layer 104 as indicated by an arrow in FIG.

  Furthermore, when light that has passed through the color filter layer 104 enters the second base layer 103, reflection occurs at the interface, but the difference between the refractive index nc of the color filter layer 104 and the refractive index n2 of the second base layer 103 is calculated. By setting it to preferably 0.1 or less, more preferably 0.05 or less, reflection at the interface can be prevented.

  The light that has passed through the second base layer 103 is further incident on the first base layer 102. The second base layer 103 has a refractive index n2 of the second base layer 103 at the wavelength of the light extracted by the color filter layer 104. Since fine particles having different refractive indexes are dispersed, when light enters the second underlayer 103, the light is scattered by the fine particles contained in the layer. On the other hand, when the refractive index n1 of the first underlayer 102 is preferably set to 1.4 or less, more preferably 1.3 or less, a critical angle is obtained when light enters the first underlayer 102 from the second underlayer 103. However, since light is scattered in the second underlayer 103, the light enters the first underlayer 102 from the second underlayer 103 at an angle equal to or greater than the critical angle. The light that has undergone total reflection at the interface with the first ground layer 102 and returned to the second ground layer 103 is scattered inside the second ground layer 103 to change the traveling direction of the light, and the first ground layer again at a different angle. 102 is incident. For this reason, since the angle of light incident at an angle greater than the critical angle changes every time scattering occurs, the light can enter the first underlayer 102 as indicated by an arrow in FIG.

  Furthermore, the critical angle θc when the light that has passed through the first underlayer 102 passes through the substrate and finally exits to the air layer (external world) having a refractive index of 1.0 is sin θc = 1 / n (n is the refractive index of the substrate). However, when the incident angle is θ ′ when incident on the substrate from the first underlayer 102, the angle θ of the light entering the substrate follows Snell's law sin θ = sin θ ′ · (n1 / n). In order to cause refraction, the critical angle θ′c with respect to the air layer viewed from the first underlayer 102 is expressed as sin θ′c = 1 / n1, and the critical angle is determined by n1 regardless of the refractive index n of the substrate, By making the refractive index n1 of the first underlayer 102 preferably 1.4 or less, the critical angle to the outside can be increased to about 46 ° or more, and more preferably 1.3 or less. This makes it possible to increase the critical angle to the outside world to about 50 ° or more. That.

  FIG. 4 is a schematic sectional view showing an organic electroluminescence element 400 according to the second embodiment of the present invention. The organic electroluminescent element 400 shown in FIG. 4 has the same structure as the organic electroluminescent element 100 shown in FIG. 1 except that a smoothing layer 401 is provided between the third base layer 105 and the electrode 106.

  In the present invention, the color filter layer 104 contains fine pigment particles, and the second underlayer 103 and the third underlayer 105 contain fine particles having a refractive index different from the refractive index of the underlayer. For this reason, the surface of the third underlayer 105 is uneven. When the organic light emitting layer 107 sandwiched between the two electrodes 106 and 108 is formed thereon, unevenness occurs in the organic light emitting layer 107 due to the unevenness of the underlying layer, and the two electrodes 106 and 108 are locally short-circuited. There is a possibility that a part will occur. In addition, the color filter layer 104 is patterned according to the shape of the sub-pixel, and the film thickness is about 1 to several μm. There is a possibility that the formed electrode is disconnected. Therefore, by forming the smoothing layer 401 between the third underlayer 105 and the electrode 106, it is possible to eliminate the unevenness of the underlayer and the step at the end of the color filter layer 104 pattern. However, the difference in refractive index between the smoothing layer 401 and the organic light emitting layer 107 causes a critical angle problem and a reflection problem as in the refractive index difference between the base layer and the organic light emitting layer. Therefore, if the refractive index of the smoothing layer 306 is preferably set to 1.7 or more, the light extraction efficiency can be increased for the same reason as described above, and if the refractive index of the organic light emitting layer is high, the smoothing is performed. If the refractive index of the layer 401 is more preferably set to 1.8 or more, the light extraction efficiency can be increased for the same reason as described above.

  FIG. 5 is a schematic cross-sectional view showing an organic electroluminescence element 500 according to the third embodiment of the present invention. The organic electroluminescent element 500 has the same structure as the organic electroluminescent element 400 shown in FIG. 4 except that a gas barrier layer 501 is further provided on the smoothing layer 401.

  As the binder resin for the color filter layer 104, an acrylic resin is generally widely used, but these resins often have a hydrophilic functional group so that alkali development can be performed. Therefore, in the process of forming the color filter layer 104, water molecules are adsorbed inside the resin, and this adsorbed water may act on the organic light emitting layer and the electrodes, causing deterioration of elements such as dark spots. Therefore, it is preferable to form the gas barrier layer 501 between the color filter layer 104 or the smoothing layer 401 and the electrode 106. However, the difference in refractive index between the gas barrier layer 501 and the organic light emitting layer 107 causes the critical angle problem and the reflection problem as well as the refractive index difference between the base layer and the organic light emitting layer. Therefore, if the refractive index of the gas barrier layer 407 is preferably set to 1.7 or more, the light extraction efficiency can be increased for the same reason as described above. Further, if the refractive index of the organic light emitting layer 107 is high, the gas barrier layer If the refractive index of the layer 501 is more preferably 1.8 or more, the light extraction efficiency can be increased for the same reason as described above.

  The display device of the present invention uses the organic electroluminescence element with improved light extraction efficiency of the present invention, can reduce the power consumption of the display device, and reduce the current flowing through the organic electroluminescence element. Therefore, the lifetime of the element can be extended.

  As the substrate used for the organic electroluminescence of the present invention, a substrate having translucency in visible light is used. In terms of translucency, the transmittance of the substrate is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The refractive index is not particularly limited as long as it has a refractive index higher than that of the underlying layer, but in the case of a high refractive index substrate with a refractive index exceeding 1.8, external light on the substrate surface This is not preferable because the reflectance of the light becomes high and the reflection of external light becomes remarkable. Further, since the refractive index of the first underlayer is smaller than the refractive index of the substrate, the critical angle θ′c of the first underlayer with respect to the air layer is larger than the critical angle θc of the substrate with respect to the air layer. Therefore, compared to the case without the first underlayer, the light totally reflected at the interface between the substrate and the outside returns to the underlayer and is scattered at the interface between the underlayer and the color filter layer, and the angle is changed below the critical angle. The light that enters the substrate again and reaches the outside world is reduced. Therefore, it is possible to suppress the occurrence of pixel blur due to multiple reflection and scattering through the thick substrate 101 as shown in FIG. Note that FIG. 6 shows that in the present invention, when the first underlayer 102 is not provided, the light that has undergone total reflection at the interface between the substrate 101 and the air returns to the second underlayer 103 to be scattered again, and changes the traveling direction from the light source. It is the figure which showed the case where it will be taken out outside in the distant position.

  As a substrate suitably used for such applications, optical substrates such as BK7, BaK1, and F2, quartz glass, non-alkali glass used for liquid crystal displays, borosilicate glass, aluminosilicate glass, and other glass substrates, PMMA, and the like Examples thereof include resin substrates such as acrylic resins, polycarbonate resins, polyethersulfone resins, styrene resins such as polystyrene, polyolefin resins, epoxy resins, and polyester resins such as polyethylene terephthalate. Moreover, although the thickness of a board | substrate is 0.1 mm-10 mm normally, when mechanical strength and the weight of a board | substrate are considered, Preferably it is 0.3-5 mm, More preferably, it is 0.5-2 mm.

  For the first underlayer, a material having a refractive index of preferably 1.4 or less, more preferably 1.3 or less is used. The refractive index of the first underlayer is preferably low, but if it is too low, the mechanical strength of the layer is lowered, which is not preferable. The refractive index of the first underlayer is usually 1.0 or more.

  The first underlayer can be formed of porous silica, fluorine-containing resin (fluororesin) or fluoride salt, and porous silica is particularly preferably used.

  When porous silica is used for the first underlayer, a method such as a method for preparing mesoporous silica such as MCM-41 announced by US Mobile in 1992 can be used. (C. T. Kresge et al., Nature, 359, 710, 1992, etc.) In this method, a self-organizing surfactant or liquid crystal and a silicate solution serving as a silica source are prepared as a template. By adjusting the pH, a tissue structure such as micelles and lamellas is created, and a solution in which silicate is dispersed in a mesh shape is applied to the substrate in the gaps between the tissues. As a means for coating, known methods such as spin coating, dip coating, slit coating, die coating, roll coating, spray coating and the like can be used. After applying the above silica precursor solution onto the substrate by these coating methods, the substrate is dried and then fired at a temperature of 200 ° C. to 550 ° C. under normal pressure or reduced pressure to form a micelle or lamella as a mold. A porous silica thin film can be obtained by removing the organic substances forming the.

  In addition, as the fluororesin used for the first underlayer, a polymerizable monomer having a perfluoroalkyl group, such as a (meth) acrylic acid-containing fluorine-containing alkyl ester, a fluorine-containing alkylstyrene, a perfluoro group having a perfluoro group in the side chain (meth) Acrylic acid, fumaric acid / maleic acid having a perfluoro group in the side chain, a fluorine-containing epoxy monomer having a perfluoro group and a glycidyl group, a polymer obtained by polymerizing these monomers, and the like, are limited thereto. In addition, additives for improving the coating property may be added to these monomers and polymers as necessary, or a polymerization initiator may be added to these monomers and polymers, and a plurality of the aforementioned monomers may be mixed as necessary. May be used. These monomers and polymers are dissolved in an appropriate solvent to prepare a composition, and then the composition is applied onto a substrate. As a means for coating, known methods such as spin coating, dip coating, slit coating, die coating, roll coating, spray coating and the like can be used. The coating film can be polymerized by means of heat, light, electron beam or the like as necessary after drying. Further, the translucency of the base layer is preferably 90% or more, more preferably 95% or more, and still more preferably 97% or more over the entire visible light. In addition, the (meth) acryl in this invention means both methacryl and an acryl.

  Further, when a fluoride salt is used for the first underlayer, magnesium fluoride, lithium fluoride, sodium fluoride, sodium aluminum fluoride (cryolite), or the like can be used. As means for thinning these salts on the substrate, vapor deposition or sputtering by resistance heating or electron beam heating can be used.

  The color filter layer is a layer that transmits only light of a desired wavelength from the light of the light source and cuts unnecessary light. Further, in a full-color organic electroluminescence display or a multi-color organic electroluminescence display, it is necessary to pattern a layer according to the shape of the pixel of the display. Currently, color filters for liquid crystal displays are widely used as color filters for displays. Conventionally, methods for producing these color filters for liquid crystals include pigment dispersion methods, dyeing methods, electrodeposition methods, printing methods, ink jet methods, and the like. The color filter layer in the present invention can also be produced using these methods, but it is particularly preferable to use a pigment dispersion method, a printing method, or an ink jet method.

  The pigment dispersion method is a method in which a photosensitive coloring composition containing a color pigment, a binder resin, a crosslinking agent, and a photopolymerization initiator is applied onto a substrate and patterned by photolithography. The photosensitive coloring composition can be applied onto a substrate by means such as spin coating, dip coating, slit coating, die coating, roll coating, spray coating and the like. Of these methods, the method of applying a photosensitive coloring composition to a substrate mainly by spin coating has been the mainstream. However, recently, the substrate is roughly coated by slit coating to increase the size of the substrate and save liquid. A method of applying a photosensitive coloring composition to the substrate and then spinning the substrate to obtain a desired film thickness (slit spin method) or a method of applying the substrate only by slit coating has become the mainstream. A substrate coated with the photosensitive coloring composition is exposed to a photomask corresponding to a desired pattern. The photosensitive coloring composition is usually a negative type in which the exposed portion is cured, and the exposure light is usually ultraviolet light mainly composed of i-line (wavelength 365 nm) using an ultrahigh pressure mercury lamp as a light source. Development can be carried out with an organic solvent or alkali development, but alkali development with a small environmental load is the mainstream. The developed pattern decomposes and evaporates the unreacted polymerization initiator and the solvent in the resin by baking and removes the pattern to completely cure the pattern. This method is repeated as many times as necessary to obtain a color filter. A color filter for separating a white light source into three colors of RGB is prepared by performing this operation three times using three kinds of photosensitive coloring compositions.

  The printing method is a method of printing on a substrate an ink obtained by mixing a color pigment, a binder resin, and a solvent. As a printing method, known methods such as gravure printing, screen printing, letterpress printing, planographic printing, and reversal printing can be used. Ink jet method supplies ink that is a mixture of color pigment, binder resin and solvent to the discharge part of the ink jet nozzle, and ink particles are ejected from the nozzle by vibration and thermal energy of the piezo element, depending on the pattern shape In this method, a color filter is formed by causing droplets to land on the substrate. In the case of the ink jet method, as described in JP-A-59-75205, there is a limit to the accuracy of the landing position of the ink ejected from the nozzle. A pattern made of a liquid repellent material called a bank is prepared, and when the ink ejected from the nozzle deviates from the target pixel to be deposited, The ink repels in the bank and moves to the pixel portion to accurately form the pattern shape.

  In addition, in the case of a liquid crystal display, a light shielding film called a black matrix may be formed in a gap portion between pixels in order to prevent the backlight light from leaking from the wiring portion and reducing the contrast of the image. In many cases, the bank is also provided with a light-shielding function and also functions as a black matrix.

  As the coloring composition used for forming the color filter layer, the material of the color filter for liquid crystal display can be used as it is. A resin widely used for the base resin of the color filter layer is an acrylic resin, an epoxy resin, a polyimide resin, or the like, but a technique using an acrylic resin is mainstream from the viewpoint of transparency and manufacturing cost.

  The color material used for the coloring composition forming the color filter layer is not particularly limited as long as it is suitable for this application, but as the color material, a pigment is preferably used from the viewpoint of weather resistance and heat resistance. Examples of pigments include C.I. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 55, 83, 86, 93, 109, 110, 117, 125, 137, 139, 147, 148, 153, 154, 166, 168, C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, C.I. I. Pigment Red 9, 97, 122, 123, 149, 168, 177, 180, 192, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, C.I. I. Pigment Violet 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment Blue 15, 15: 1, 15: 4, 15: 6, 22, 60, 64, C.I. I. Pigment Brown 23, 25, 26, C.I. I. Pigment Black7 etc. are mentioned, but it is not limited to these. A plurality of these pigments may be mixed and used according to the desired color tone.

  Various dispersing means such as a roll mill, a sand mill, an attritor, a ball mill, a kneader, a paint shaker, and an ultrasonic disperser can be used as a means for dispersing these pigment fine particles in the color composition for forming a color filter. Various dispersion aids can also be added to improve the dispersion of the pigment fine particles and prevent reaggregation.

  In the present invention, when the means for forming the color filter layer is a pigment dispersion method, the monomer added to give the color composition for forming the color filter photocurable is particularly limited as long as it is suitable for this application. Although there are no examples, (meth) acrylic acid, methyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) (Meth) acrylic acid esters such as acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane tris (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetrakis (meth) acrylate, dipentaerythritol hexakis (meth) Acryle Polyfunctional acrylic monomer bets like, but is not limited to these there are monomers having an epoxy such as glycidyl (meth) acrylate. Moreover, you may use these monomers in mixture suitably, as needed.

  Further, in the present invention, when the means for forming the color filter layer is a pigment dispersion method, the photopolymerization initiator added for imparting photocurability to the coloring composition for forming the color filter is suitable for this application. If it is, there will be no restriction | limiting in particular, As a photoinitiator added to the coloring composition for color filter formation, what is reported by various literature can be used. Examples of these photopolymerization initiators include acetophenone, benzophenone, benzyldimethylketanol, 2-chlorothioxanthone, 2-ethylanthraquinone, diethylthioxanthone (Kayacure DETX: manufactured by Nippon Kayaku), 1-hydroxycyclohexyl phenyl ketone ( Irgacure 184: manufactured by Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone (Irgacure 369: manufactured by Ciba Specialty Chemicals), 2,2-dimethoxy-1, 2-diphenylethane-1-one (Irgacure 651: manufactured by Ciba Specialty Chemicals), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Irgacure 819: Ciba Specialty) Chemicals), 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure 907: Ciba Specialty Chemicals), biimidazole compounds, etc., but are not limited thereto. It is not something. Moreover, you may use these photoinitiators in mixture of plurality suitably as needed.

  In the present invention, even if the means for forming the color filter layer is other than the pigment dispersion method, the photocurable monomer, the light is used for the purpose of imparting stability and mechanical strength to the formed color filter layer film. A film may be cured by light irradiation after patterning by adding a polymerization initiator. In addition, a thermosetting monomer may be added to cure the film by thermosetting.

  Furthermore, the colored composition for forming the color filter layer of the present invention may use various solvents in order to obtain viscosity suitable for various coating processes, stability of the colored composition, and smoothness of the coating film during coating. it can. Examples of solvents include methanol, ethanol, toluene, cyclohexane, isophorone, cellosolve acetate, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, xylene, ethylbenzene, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Examples include, but are not limited to, isoamyl acetate, ethyl lactate, ethyl methyl ketone, cyclohexanone, acetone, propylene glycol diacetate, ethyl ethoxypropionate, butyl carbitol, carbitol acetate, and the like. Moreover, you may use these various solvents in mixture suitably, as needed. Moreover, you may add various additives in order to obtain the smoothness of the coating film at the time of application | coating.

  In the present invention, even if the means for forming the color filter layer is other than the pigment dispersion method, the photocurable monomer, the light is used for the purpose of imparting stability and mechanical strength to the formed color filter layer film. A film may be cured by light irradiation after patterning by adding a polymerization initiator. In addition, a thermosetting monomer may be added to cure the film by thermosetting.

  In the present invention, the refractive index n2 of the second underlayer formed between the first underlayer and the color filter layer is the color filter at the wavelength of the light extracted by the color filter layer. The difference from the refractive index nc of the layer is 0.1 or less, more preferably 0.05 or less. Therefore, the material used for the first underlayer varies depending on the material used for the color filter layer, but the difference between n2 and nc can be reduced by using the material used for the first underlayer as the base resin of the color filter. it can. Moreover, you may add a photocurable monomer or a thermosetting monomer in order to add photocurability and thermosetting to the composition for 1st base layer formation.

  Furthermore, various solvents can be used in the composition for forming the second underlayer of the present invention in order to obtain a viscosity suitable for various coating processes, stability of the composition, and smoothness of the coating film during coating. . Examples of solvents include methanol, ethanol, toluene, cyclohexane, isophorone, cellosolve acetate, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, xylene, ethylbenzene, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Examples include, but are not limited to, isoamyl acetate, ethyl lactate, ethyl methyl ketone, cyclohexanone, acetone, propylene glycol diacetate, ethyl ethoxypropionate, butyl carbitol, carbitol acetate, and the like. Moreover, you may use these various solvents in mixture suitably, as needed. Moreover, you may add various additives in order to obtain the smoothness of the coating film at the time of application | coating. Examples of means for coating the substrate with the composition for forming the second underlayer include various coating means such as spin coating, dip coating, slit coating, die coating, roll coating, and spray coating.

  Further, in the present invention, in order to provide the second underlayer with a scattering property, the composition for forming the second underlayer has a refraction of the color filter layer at the wavelength at the wavelength of light extracted by the color filter layer. Fine particles having a refractive index different from the refractive index are dispersed. The dispersed fine particles are not particularly limited as long as they have a refractive index different from that of the material of the second underlayer and have a scattering property, but metals, metal compounds, silicon compounds, resins, or mixtures thereof can be preferably used. . Here, an oxide or nitride of titanium, zirconium, aluminum, or cerium can be used as the metal compound. Further, if the size of the fine particles to be added is too small, the scattering property is lost, which is not preferable. Therefore, the particle size is 50 nm or more, preferably 70 nm or more. Furthermore, if the particle size of the fine particles to be added is too large, it is not preferable because it causes the surface roughness of the film surface of the second underlayer, so that the particle size is 5 μm or less, preferably 1 μm or less. Even if the particle size of the primary particles is less than 50 nm, the particles can be used as long as the particles are aggregated to some extent and the particle size of the aggregated secondary particles is 50 nm or more. Further, as the means for dispersing the scattering fine particles in the composition for forming the second underlayer, the same means as the means for dispersing the pigment fine particles in the coloring composition can be used. Further, a dispersion aid may be used to assist dispersion or prevent re-aggregation of fine particles after dispersion. In particular, when the second underlayer is an organic material such as a resin and the dispersed fine particles are inorganic fine particles, a silane coupling agent may be added to improve the compatibility between the organic material and the surface of the inorganic fine particles.

  The third underlayer formed on the color filter layer preferably has a refractive index n3 at a wavelength of light extracted by the color filter layer of 1.7 or more, more preferably 1.8 or more. Examples of a high refractive index material having a refractive index of 1.7 or more suitable for forming a thin film include transparent resins containing zirconium, titanium, and cerium atoms, and inorganic thin films formed by a sol-gel method. When a transparent resin containing zirconium, titanium, or cerium atoms is used, there is a method in which a compound such as an alkoxide or acylate of these metals is mixed with a composition for forming a light-transmitting layer. These compounds can undergo a condensation reaction with a carboxyl group, a hydroxyl group, or the like of the resin to incorporate these metals into the resin skeleton. As the compound used, in the case of titanium, titanium alkoxide such as tetra-n-butoxy titanium, tetraisopropoxy titanium, tetra-n-propoxy titanium, tetraethoxy titanium, titanium acylate such as titanium stearate, titanium chelate, tetra -Z-butoxyzirconium, tetra-n-propoxyzirconium, tetraisopropoxyzirconium, zirconium alkoxides such as tetraethoxyzirconium, zirconium acylates such as zirconium tributoxy systemate, zirconium chelates, etc. It is not a thing.

  In addition, an inorganic polymer thin film formed by a sol-gel method is preferable because it can obtain a higher refractive index than an organic material by a simple coating method. When the third underlayer of the inorganic thin film is formed by the sol-gel method, a coating solution is prepared using a metal alkoxide such as titanium alkoxide or zirconium alkoxide as a raw material of the inorganic material forming the third underlayer, alcohols, water, etc. as a solvent. And after apply | coating this by arbitrary means on a board | substrate, a thin film can be obtained by baking at appropriate temperature. The firing temperature may be 100 ° C. to 400 ° C., but the firing temperature is preferably 100 ° C. to 250 ° C. in consideration of damage to the underlying color filter layer.

  In the third underlayer, fine particles having a refractive index different from the refractive index of the third underlayer at the wavelength of light extracted by the color filter layer are dispersed. The fine particles to be dispersed are not particularly limited as long as they have a refractive index different from that of the material of the third underlayer and have a scattering property, but metals, metal compounds, silicon compounds, resins, or mixtures thereof can be preferably used. . Here, an oxide or nitride of titanium, zirconium, aluminum, or cerium can be used as the metal compound. Further, if the size of the fine particles to be added is too small, the scattering property is lost, which is not preferable. Therefore, the particle size is 50 nm or more, preferably 70 nm or more. Further, if the particle size of the fine particles to be added is too large, it is not preferable because it causes the surface roughness of the film surface of the third underlayer, so that the particle size is 5 μm or less, preferably 1 μm or less. Even if the particle size of the primary particles is 50 nm or less, the particles can be used as long as the particles are aggregated to some extent and the particle size of the aggregated secondary particles exceeds 50 nm. Further, as a means for dispersing the scattering fine particles in the composition for forming the third underlayer, various dispersing means such as a roll mill, a sand mill, an attritor, a ball mill, a kneader, a paint shaker, and an ultrasonic dispersing machine can be used. Various dispersion aids can also be added to improve the dispersion of the fine particles and prevent reaggregation. In particular, when resin fine particles are dispersed in the inorganic third underlayer material, a silane coupling agent may be added to improve the affinity of the organic / inorganic material.

  The smoothing layer provided in the present invention has a higher refractive index in order to increase the light extraction efficiency for the same reason that the higher refractive index of the third underlayer is preferable. As a material having a high refractive index suitable for this application, a transparent resin containing zirconium, titanium, and cerium atoms, an inorganic thin film formed by a sol-gel method, and the like can be used as in the third underlayer. In particular, an inorganic thin film formed by a sol-gel method is preferable because it can obtain a higher refractive index than an organic material. When forming a smoothing layer of an inorganic thin film by a sol-gel method, a coating solution is prepared using a metal alkoxide such as titanium alkoxide or zirconium alkoxide, which is a raw material of the inorganic material forming the smoothing layer, alcohols, water, etc. as a solvent, A smoothing layer can be obtained by applying this onto a substrate by any means and then baking at an appropriate temperature. The firing temperature may be 100 ° C. to 400 ° C., but the firing temperature is preferably 100 ° C. to 250 ° C. in consideration of damage to the underlying color filter layer. Alternatively, a composition obtained by removing only the scattering particles from the composition for forming the third underlayer may be used as the composition for forming the smoothing layer.

  Further, various additives may be added for the purpose of obtaining the smoothness of the coating film when the third underlayer and the smoothing layer of the present invention are applied. Various coating means such as spin coating, dip coating, slit coating, die coating, roll coating, spray coating, etc. are used as means for coating the substrate with the composition for forming the third underlayer or the composition for forming the smoothing layer. Can be mentioned.

  In the present invention, the material of the gas barrier layer preferably has a high refractive index for the same reason as that of the above-described third underlayer having a high refractive index, and has a refractive index at the wavelength of light extracted by the color filter layer. It is preferably 1.7 or more, more preferably 1.8 or more.

  In general, a barrier layer used in an organic electroluminescence element is a thin film such as silicon nitride, silicon oxynitride aluminum oxide or the like, and since the refractive index of these thin films is sufficiently higher than the refractive index of an organic substance, there is no problem. However, silica often used in the gas barrier layer is not preferable in the present invention because the refractive index is as low as about 1.5. The film thickness is preferably in the range of 0.1 to 10 μm, and more preferably 0.1 to 1 μm in view of film stress and transparency. The method for forming the barrier layer in the present invention is not particularly limited as long as it can be used for this application, but various sputtering methods such as DC sputtering, RF sputtering, magnetron sputtering, ECR sputtering, counter target sputtering, and ion beam sputtering, Examples thereof include ion plating and CVD.

  In the present invention, the color filter layer divides the color of the light source and combines the colors to develop the color of the full color or multi-color display. Therefore, the number of subpixels is 3 or more. Is preferred. In general, the sub-pixels of the color filter of a full-color display often divide the light source white into three RGB colors, but recently, a display having four or more sub-pixels has been devised in order to expand the color reproduction range. The present invention can also take such a subpixel format.

  In addition, a transparent conductive film is used as an electrode for extracting light generated in the organic light emitting layer. As the transparent conductive film, metal oxides such as indium / tin oxide (ITO), indium / zinc oxide (IZO), and zinc oxide are usually used, but indium / tin oxide is particularly preferable in terms of transparency and conductivity. Is preferred. The film thickness of the transparent electrode layer is 80 to 400 nm, preferably 100 to 200 nm, from the viewpoint of ensuring transparency and conductivity. As a method for forming the transparent conductive film, a known method such as a sputtering method or an ion plating method can be used. In the case of a dot matrix display, it is necessary to pattern the transparent conductive film according to the shape of the pixel and the wiring. In the present invention, a known method can be used as a method for patterning the transparent electrode. A typical method is patterning by photolithography. In this case, a photoresist is applied to the substrate on which the transparent conductive film is formed by a method such as spin coating, and pattern exposure is performed using a photomask corresponding to the electrode pattern. Further, the transparent electrode is patterned by a method such as sandblasting, dry etching, or wet etching using an acid such as aqua regia on the substrate on which the resist has been patterned by development. It is also preferable to perform oxygen plasma treatment or UV ozone treatment on the transparent conductive film patterned before forming the organic light emitting layer. In this case, organic matter contamination on the surface of the transparent conductive film is removed, and when the transparent electrode is indium tin oxide, the work function of indium tin oxide is increased by oxygen plasma treatment or UV ozone treatment. It is known that holes can be easily injected into the device, and the performance of the device is improved.

  The organic light emitting layer formed on the transparent electrode layer is decomposed into a plurality of colors by the color filter layer to form the color of a subpixel of a full color or multicolor display. It is preferably white. However, the white color obtained by additively mixing the light extracted outside is the white color after passing the light from the light source through the color filter, so even if the emission color from the light emitting layer is not strictly white, The color filter can be corrected to some extent by optimizing the color of the color filter. In order to obtain white light emission, the method of forming a light emitting layer with a material that emits white light is the simplest, but generally there are few such substances. Therefore, a method of emitting white light by using a plurality of materials having different emission colors is generally used. In this case, as a method for emitting white light, the host of the light emitting layer is doped simultaneously with a dopant that emits blue light and a dopant that emits yellow to red light, and white is obtained by adjusting the dopant concentration. A method of doping each light emitting layer with a blue light emitting dopant and a yellow to red light emitting dopant, doping a light emitting layer with a blue light emitting dopant, and a hole transporting layer with a yellow to red light emitting dopant. However, since white is produced by two-color emission, there is a problem that color rendering properties are generally poor or the color reproduction range is narrow when combined with a color filter. There is also a method of creating a white light emitting device by doping a host with three or more kinds of dopants showing different emission colors and mixing three or more colors, but it is difficult to balance the doping concentration, and the layer structure There is a problem that becomes complicated.

  On the other hand, each light emitting unit partitioned by the charge generation layer is stacked as described in JP-A-2003-272860, and each light emitting unit has a different color, for example, using a method of individually emitting light. By using a method that emits blue light, green light, and red light and creates a white color by mixing the colors, the above problems do not occur, and white light with excellent color rendering and color reproducibility can be emitted. become. Further, when a full color matrix display is manufactured by the method disclosed in Japanese Patent Application Laid-Open No. 2003-272860, the mask evaporation process increases the number of steps of the light emitting unit in the method of forming subpixels by separately applying the light emitting layer using mask vapor deposition. However, by making a matrix display in combination with the color filter of the present invention, a highly efficient display can be produced without increasing the number of steps.

  The element was manufactured based on the manufacturing method of the organic electroluminescent element shown by embodiment of this invention below. However, the present invention is not limited to the conditions of this embodiment. In the following examples and comparative examples, “parts” and “%” are based on weight.

Example [Formation of First Underlayer and Second Underlayer]
A glass substrate having a thickness of 0.7 mm is thoroughly washed, and then an ISM-2 made by ULVAC (a porous silica containing hexamethyldisiloxane or hexamethyldisilazane is formed as a low refractive index first base layer forming coating solution. Coating solution) was applied by spin coating, the substrate was dried, and then baked at 400 ° C. using an oven depressurized to 5 Pa to form a first underlayer. The film thickness of the first underlayer on the baked substrate was 350 nm. Next, disperse titania fine particles with an average particle diameter of 150 nm in a solution of transparent acrylic resin and dipentaerythritol hexaacrylate (polyfunctional acrylic monomer) as a curing agent dissolved in propylene glycol monomethyl ether acetate, and disperse with an ultrasonic homogenizer. Thus, a coating solution for forming a second underlayer was prepared. This coating solution was applied onto the substrate by spin coating, dried and baked. The titania particles contained in the second underlayer film were 30%. The average film thickness of the second underlayer was 500 nm.

[Formation of color filter layer]
(Preparation of resin solution)
A 1-liter four-necked flask is charged with 350 parts of cyclohexanone, 26 parts of styrene, 23 parts of 2-hydroxyethyl acrylate, 35 parts of methacrylic acid, 21 parts of methyl methacrylate, and 70 parts of butyl methacrylate and heated to 90 ° C. A mixture of 290 parts of cyclohexanone, 26 parts of styrene, 23 parts of 2-hydroxyethyl acrylate, 35 parts of methacrylic acid, 21 parts of methyl methacrylate, 70 parts of methacrylic acid butyl and 1.75 parts of azobisisobutyronitrile. The solution was added dropwise over 3 hours and further reacted at 90 ° C. for 3 hours. Further, 0.75 parts of azobisisobutyronitrile dissolved in 10 parts of cyclohexanone was added, and the reaction was further continued for 1 hour to synthesize a resin solution. A portion of this resin solution was sampled and heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 30%.

(Preparation of blue color filter composition)
As a coloring material, 2.7 parts of Lionol Blue E (manufactured by Toyo Ink) and 0.3 part of a dispersant were mixed and dispersed with a paint shaker for 24 hours to obtain a blue dispersion. Next, 54 parts of a blue dispersion, 4 parts of dipentaerythritol hexaacrylate, and 19 parts of cyclohexanone were sufficiently mixed in a container to prepare a dispersion. Furthermore, 0.5 parts of ethyl Michler ketone and 0.5 parts of ethyl anthraquinone were added as photopolymerization initiators to 60 parts of this dispersion, and cyclohexanone was further added to adjust the total nonvolatile content to 25%. The mixture was filtered through a 1 micron filter to prepare a blue color filter composition.

(Preparation of composition for green color filter)
As a coloring material, 4 parts of Pigment Green 36, 1.7 parts of Pigment Yellow 154, 0.29 parts of a dispersant, 55 parts of the above resin solution, and 7.8 parts of cyclohexanone solution are mixed and dispersed with a paint shaker for 24 hours. A green dispersion was prepared. Next, 54 parts of this green dispersion, 4 parts of dipentaerythritol hexaacrylate, and 19 parts of cyclohexanone were thoroughly mixed in a container to prepare a dispersion. Furthermore, 0.5 parts of ethyl Michler ketone and 0.5 parts of ethyl anthraquinone were added as photopolymerization initiators to 60 parts of this dispersion, and cyclohexanone was further added so that the total nonvolatile content was 25%. The mixture was filtered through a 1 micron filter to prepare a green color filter composition.

(Preparation of composition for red color filter)
As a coloring material, 4 parts of Pigment Red168, 1.7 parts of Pigment Orange 36, 0.29 parts of a dispersant, 55 parts of the above resin solution, and 7.8 parts of cyclohexanone are mixed and dispersed with a paint shaker for 24 hours. A red dispersion was prepared. Next, 54 parts of this green dispersion, 4 parts of dipentaerythritol hexaacrylate, and 19 parts of cyclohexanone were thoroughly mixed in a container to prepare a dispersion. Furthermore, 0.5 parts of ethyl Michler ketone and 0.5 parts of ethyl anthraquinone were added as photopolymerization initiators to 60 parts of this dispersion, and cyclohexanone was further added to adjust the total nonvolatile content to 25%. The mixture was filtered through a 1 micron filter to prepare a red color filter composition.

(Color filter patterning)
The blue color filter composition prepared as described above was applied by spin coating to the substrate on which the second underlayer was formed. After the coating film was dried, a photomask having a negative pattern corresponding to the shape of the pixel was applied, and exposure was performed with a mask aligner. After exposure, the substrate was developed with 1% sodium carbonate solution and baked on a 220 ° C. hot plate to obtain a blue color filter pattern. Similarly, the green color filter and the red color filter were also patterned. The film thickness of the obtained color filter layer was 700 nm.

[Formation of overcoat layer]
55 parts of the resin solution prepared at the time of forming the color filter layer, 4 parts of dipentaerythritol hexaacrylate, and 19 parts of cyclohexanone were thoroughly mixed in a container to prepare a coating solution. Furthermore, 0.5 parts of ethyl Michler ketone and 0.5 parts of ethyl anthraquinone were added as photopolymerization initiators to 60 parts of this coating solution, and cyclohexanone was further added to adjust the total nonvolatile content to 25%. The solution was filtered through a 1 micron filter to prepare an overcoat coating solution. Next, the coating solution was spin coated on the color filter layer, and after the coating film was dried, a negative pattern photomask corresponding to the shape covering the color filter matrix of each color was applied, and exposure was performed with a mask aligner. . After the exposure, the substrate was developed with a 1% sodium carbonate solution and baked on a hot plate at 220 ° C. to obtain an overcoat layer pattern. The film thickness of the overcoat layer was 300 nm.

[Formation of third underlayer]
A 3% ethanol solution of 2N hydrochloric acid is added dropwise to a 1% isopropanol solution of titanium tetraisopropoxide to prepare a sol solution, and silica fine particles having an average particle size of 110 nm are mixed with this, followed by thorough stirring and dispersion. I let you. This solution was applied onto the substrate by spin coating, and heated on a hot plate at 200 ° C. to form a third underlayer which was a high refractive index scattering layer in which silica fine particles were dispersed in amorphous titania. The film thickness was 170 nm. Further, a sol solution with particles removed was prepared, and spin coating and baking were performed in the same manner to obtain a smoothing layer having a high refractive index. The film thickness of the smoothing layer was 100 nm. Next, a 150 nm thick silicon monooxide (SiO) thin film was deposited on the substrate as a gas barrier layer.

[Formation of electrode and organic light emitting layer]
An indium tin oxide (ITO) film having a thickness of 150 nm was formed on the substrate by RF sputtering, and an anode was obtained by etching into a pixel shape. Further, after cleaning with detergent and ultrasonic, the electrode surface was cleaned by irradiating with UV light from a low-pressure UV lamp in an ozone atmosphere. Subsequently, this substrate was put into a vacuum vapor deposition machine, and each organic layer was vapor-deposited in the following order.

Hole injection layer: Copper phthalocyanine represented by the following formula 1 was formed to a thickness of 15 nm at a deposition rate of 0.2 nm / second.

Light emitting layer 1: α-NPD represented by the following formula 2 was formed to a thickness of 20 nm at a deposition rate of 0.2 nm / second. At that time, 1% by weight of rubrene represented by the following formula 3 was doped.

Light-emitting layer 2: Dinaphthyl anthracene represented by the following formula 4 was formed to a thickness of 30 nm at a deposition rate of 0.2 nm / second. At that time, 1% by weight of perylene represented by the following formula 5 was doped.

Electron injection layer: Alq3 represented by the following formula 6 was formed to a thickness of 30 nm at a deposition rate of 0.2 nm / second.

  Next, lithium fluoride is formed to a thickness of 0.5 nm (deposition rate 0.01 nm / second) on the electron injection layer, and finally aluminum is evaporated to 150 nm (deposition rate 5 nm / second) according to the cathode pattern. And it sealed in the glove box and obtained the element.

Comparative Example A comparative device was prepared for comparison with the example. In this element, the first ground layer, the second ground layer, and the third ground layer are omitted from the configuration of the above embodiment. The remaining color filter layer, overcoat layer, gas barrier layer, electrode, and organic light emitting layer were prepared by the same materials and processes as in the above examples.

Table 1 shows the results of calculating the light extraction efficiency of the color filter from the obtained spectra by energizing the elements of the example and the comparative example.

  Table 1 shows the chromaticity and brightness of each emission color when a white + color filter type device is manufactured and a comparative device is manufactured based on the embodiment of the present invention. In the device of the example of the present invention, both brightness and color reproduction range at the time of white light emission are simultaneously improved as compared with the comparative example. Originally, it is impossible to improve brightness and color gamut at the same time only by controlling the film thickness of the color filter, but it is possible to improve both performances at the same time by incorporating the light extraction structure into the color filter. It was.

1 is a schematic cross-sectional view showing an organic electroluminescence element according to a first embodiment of the present invention. In the organic electroluminescence device shown in FIG. 1, the incident light from the third underlayer 105 to the color filter layer 104 at an angle greater than the critical angle, and the reflected light returns to the third underlayer 105 to cause scattering inside the 105. A state in which the traveling direction of light is changed and incident on the light 104 again is illustrated. In the organic electroluminescence device shown in FIG. 1, the incident light is incident on the first underlayer 102 from the second underlayer 103 at an angle greater than the critical angle, and the reflected light returns to the second underlayer 103 to cause scattering inside the 103. The figure shows how the light travels in the different direction and is incident on 102 again. The schematic sectional drawing which shows the organic electroluminescent element which concerns on a 2nd aspect. The schematic sectional drawing which shows the organic electroluminescent element which concerns on a 3rd aspect. In the organic electroluminescence element shown in FIG. 1, when the first underlayer 102 is not provided, the light that has undergone total reflection at the interface between the substrate 101 and the air returns to the second underlayer 103 to be scattered again, and changes the traveling direction to change the light source. It is the figure which showed the case where it will be taken out outside in the position away from.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100, 400, 500 ... Organic electroluminescent element 101 ... Substrate 102 ... 1st base layer 103 ... 2nd base layer 104 ... Color filter layer 105 ... 3rd base layer 106, 108 ... Electrode 107 ... Organic light emitting layer 401 ... Smoothing Layer 501 ... Gas barrier layer

Claims (17)

  An organic electroluminescent device comprising at least one organic light emitting layer having a light emitting region on a substrate, an anode for injecting holes into the organic light emitting layer, and a cathode for injecting electrons. Includes a first underlayer, a second underlayer, a color filter layer, and a third underlayer in this order from the substrate side, and out of the light emitted by the organic light emitting layer at the wavelength of the light extracted by the color filter. When the refractive indexes of the first base layer, the second base layer, and the third base layer are n1, n2, and n3, respectively, n1 <n2 and n2 <n3, and the second base layer and the third base layer The organic electroluminescence device is characterized in that fine particles having a refractive index different from the refractive index of each underlying layer are dispersed at the wavelength of light extracted by the color filter. .   Of the light emitted from the organic light emitting layer, the refractive index of the first underlayer at the wavelength of the light extracted by the color filter is smaller than the refractive index of the substrate and 1.4 or less. The organic electroluminescent element according to claim 1.   3. The organic electro of claim 2, wherein a refractive index of the first underlayer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.3 or less. Luminescence element.   4. The refractive index of the third underlayer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.7 or more. 5. 2. The organic electroluminescence device according to item 1.   5. The organic electroluminescence according to claim 4, wherein a refractive index of the third underlayer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.8 or more. element.   A smoothing layer is further provided on the third underlayer, and a refractive index of the smoothing layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.7 or more. The organic electroluminescent element according to claim 1, wherein   7. The organic electroluminescence device according to claim 6, wherein a refractive index of the smoothing layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.8 or more. .   A gas barrier layer is further provided on the smoothing layer, and a refractive index of the gas barrier layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.7 or more. The organic electroluminescent element according to any one of claims 1 to 7.   9. The organic electroluminescence device according to claim 8, wherein a refractive index of the gas barrier layer at a wavelength of light extracted by the color filter out of light emitted from the organic light emitting layer is 1.8 or more.   The difference between the refractive index of the second base layer and the refractive index of the color filter layer at a wavelength of light extracted by the color filter out of the light emitted from the organic light emitting layer is 0.1 or less. The organic electroluminescent element of any one of Claim 1 thru | or 9.   The difference between the refractive index of the second base layer and the refractive index of the color filter layer at the wavelength of the light extracted by the color filter out of the light emitted from the organic light emitting layer is 0.05 or less. The organic electroluminescent element according to claim 10.   The organic electroluminescence device according to any one of claims 1 to 11, wherein the fine particles are made of a metal, a metal compound, a silicon compound, a resin, or a mixture thereof.   The organic electroluminescence device according to claim 12, wherein the metal compound is an oxide or nitride of titanium, zirconium, aluminum, or cerium.   The organic electroluminescence element according to claim 1, wherein the first underlayer contains porous silica.   The organic electroluminescence element according to claim 1, wherein the first underlayer includes a resin having fluorine.   The organic electroluminescence element according to claim 1, wherein the first underlayer includes a fluoride salt.   The display apparatus provided with the organic electroluminescent element of any one of Claims 1 thru | or 16.

Images