JP6187915B2 - Organic light emitting diode, method for manufacturing substrate for organic light emitting diode, image display device and lighting device - Google Patents

Description

  The present invention relates to an organic light emitting diode, a method for manufacturing a substrate for an organic light emitting diode, an image display device, and an illuminating device, and more specifically, emits white light by mixing light of different wavelengths and has an uneven structure. The present invention relates to an organic light emitting diode manufactured using a diode substrate, a method for manufacturing the organic light emitting diode substrate, and an image display device and an illumination device using the organic light emitting diode.

  An organic light-emitting diode is a light-emitting element using organic electroluminescence (hereinafter referred to as organic EL-Organic Electro-Luminescence), and generally includes an organic EL layer including a light-emitting layer containing an organic light-emitting material. The structure is sandwiched between conductive layers (anode conductive layer and cathode conductive layer).

Such an organic EL layer is constituted of an electron injection layer, an electron transport layer, a hole injection layer, a hole transport layer, and the like as required in addition to the light emitting layer.

In addition, the organic light emitting diode includes an anode conductive layer made of a transparent conductive material such as indium tin oxide (ITO) on an organic light emitting diode substrate made of a glass substrate, an organic EL layer including a light emitting layer, a metal A cathode emission layer made of a material is sequentially stacked, and a bottom emission type in which light is extracted from the lower surface of the organic light emitting diode on the organic light emitting diode substrate side. The cathode conductive layer and the light emitting layer are formed on the organic light emitting diode substrate. An organic EL layer containing an anode and an anode conductive layer are sequentially laminated, and an anode top emission type in which light is extracted from the upper surface of the organic light emitting diode opposite to the organic light emitting diode substrate, on the organic light emitting diode substrate The organic EL layer including the anode layer, the light-emitting layer, and the cathode conductive layer (semi-transmissive electrode) are sequentially stacked in this order. Light from the upper surface of the opposite side of the organic light emitting diode such as those of the cathode top emission type is known to be taken out from the diode board.

  Such an organic light-emitting diode has advantages such as low viewing angle dependency, low power consumption, very thin manufacturing, and a surface light source.

Such an organic light emitting diode can be suitably used for an image display device or a lighting device. However, about 20% of the emitted energy can be extracted outside the device, and other energy is generated inside the device. Is converted into surface plasmons at the surface of the waveguide mode or cathode conductive layer that repeats total reflection at the end, and is eventually lost as heat, compared to conventional fluorescent tubes and light emitting diodes (LEDs). There was a problem that the light extraction efficiency was low.

  By the way, in order to emit white light in an organic light emitting diode, there are a two-wavelength light emitting method of mixing light of two different wavelengths and a three-wavelength light emitting method of mixing light of three different wavelengths. .

  Such a light-emitting method includes an organic light-emitting material that emits light of different wavelengths in the light-emitting layer. In such an organic light-emitting material, the internal quantum efficiency and the lifetime of the organic light-emitting material depend on the wavelength of the emitted light. Is different.

  Therefore, when the applied voltage is adjusted in accordance with the organic light emitting material having the lowest internal quantum efficiency, the applied voltage is higher than the appropriate applied voltage in the organic light emitting material having the high internal quantum efficiency.

  As a result, the inflow current increased, the current density increased, and the lifetime of the organic light-emitting material was reduced beyond the appropriate current density.

In other words, in the two light emitting methods described above, if the difference in internal quantum efficiency between the respective organic light emitting materials is large, the life of the organic light emitting material exhibiting high internal quantum efficiency is lowered, and the life as an organic light emitting diode is shortened. It was pointed out as a problem.

On the other hand, paying attention to the lifetime of the organic light emitting material, the lifetime is an inherent element derived from the chemical structure of the organic light emitting material and is determined by the type of the organic light emitting material, but further depends on the light emitting conditions. . That is, generally, when the applied voltage to the light emitting layer is high, the organic light emitting material is rapidly deteriorated, so that the lifetime is shortened.

Against this background, there has been a proposal for a white organic light-emitting diode that selectively improves the light extraction efficiency of an organic light-emitting material with low internal quantum efficiency by emitting light from a plurality of organic light-emitting materials constituting white at an appropriate applied voltage. It was desired.

  Here, the internal quantum efficiency in this specification is the ratio of the energy excited by the organic light emitting material contained in the organic EL layer to the light energy by the injected power (the light energy generated by the organic light emitting material). ).

In addition, the light extraction efficiency in this specification refers to an organic light emitting diode light extraction surface (a substrate surface in the bottom emission type and an anode top emission type) with respect to the light energy generated from the organic light emitting material contained in the organic EL layer. Is the anode surface, and in the cathode top emission type, it is the cathode surface), and indicates the ratio of light energy emitted outside the organic light emitting diode, that is, in the free space.

  By the way, as a method for improving the light extraction efficiency of the organic light emitting diode, a method of introducing a fine structure in the element has been known. Such a fine structure is roughly classified into a random structure and a periodic structure.

  Patent Documents 1 and 2 disclose a method for improving the light extraction efficiency by introducing a random fine structure with irregular height and pitch in the element in order to improve the light extraction efficiency in the visible light region.

However, this method has a function for the entire visible light region, that is, two organic light-emitting materials for the two-wavelength type, and all three organic light-emitting materials for the three-wavelength type. It has been pointed out as a problem that no effect is recognized for use in the purpose of balancing large organic light emitting materials.

  On the other hand, as a means for improving the light extraction efficiency in a specific wavelength range, a fine structure having periodicity is introduced into the element, and a waveguide mode (TE waveguide mode, TM waveguide mode and surface plasmon mode) is obtained. It is effective to take out the energy outside the device.

  As a waveguide mode light extraction method, for example, a method of introducing a diffraction grating into an element has been proposed.

  This method diffracts light that would normally be trapped in the element by total reflection by a diffraction grating provided in the element, and changes the direction of the light, thereby extracting the light from the element and improving the light extraction efficiency. It is made to let you.

  Since the diffraction grating diffracts a specific wavelength determined by the lattice constant, if the diffraction grating is introduced into an organic light emitting diode that emits white light, light extraction efficiency at a specific wavelength is improved.

  Such a technique, that is, a method for improving the light extraction efficiency by extracting the energy of the waveguide mode is disclosed in, for example, Patent Document 3. In Patent Document 3, the light emission efficiency and the light emission life are inferior. Attempts have been made to introduce diffraction gratings according to the wavelength of the material.

As described above, various attempts have been made to extract energy lost in the element by providing a periodic diffraction grating in the element. However, the organic light-emitting material having a short internal quantum efficiency and a short emission lifetime is desired. In order to extract light in accordance with the peak wavelength of the emission spectrum, the lattice constant and light extraction are determined by the element configuration, the mode of light to be extracted (TE waveguide mode, TM waveguide mode and surface plasmon mode), and the location where the diffraction grating is provided. Efficiency varies greatly. For this reason, if the design for extracting light in accordance with the peak wavelength of the emission spectrum of the organic light emitting material having a short internal quantum efficiency or emission lifetime is not made in detail, the effect of improving the light extraction efficiency is low. Met.

  Various methods for improving the light extraction efficiency by improving the energy loss via the surface plasmon have been studied, and such techniques are disclosed in Patent Documents 4 to 7, for example.

  That is, in Patent Documents 4 to 7, as a method for converting surface plasmons that are normally lost as heat into propagating light and extracting light, the surface of the cathode conductive layer, which is a metal layer, is one-dimensional or two-dimensional. A method of providing a dimensional periodic microstructure is disclosed.

The concavo-convex structure, which is a periodic fine structure formed on the surface of the cathode conductive layer, functions as a diffraction grating that diffracts the surface plasmon, and can convert the surface plasmon generated in the cathode conductive layer into propagating light again. The light extraction efficiency is improved.

  Here, the organic light emitting diode is very thin, and the distance between the light emitting layer and the cathode conductive layer, which is a metal layer, is very close, so that the light emission energy is converted to surface plasmons on the surface of the cathode conductive layer. The ratio is larger than the energy light in the waveguide mode confined in the device.

For this reason, when there is no diffraction grating for diffracting the surface plasmon, the surface plasmon converted on the surface of the cathode conductive layer is lost as heat, so that the light extraction efficiency of the organic light emitting diode is remarkably lowered.

  For this reason, as for the extraction of energy in the surface plasmon mode, an attempt has been made to extract energy lost in the element by providing a grating that diffracts the surface plasmon in the element.

  However, light extraction efficiency in a specific wavelength range that matches the peak wavelength of the emission spectrum of the organic light-emitting material with the desired internal quantum efficiency and short emission lifetime by providing periodic fine structure and utilizing surface plasmon diffraction However, it has been pointed out that it is difficult to improve the light extraction efficiency because the size of the periodic fine structure and the manufacturing method have not been established.

JP 2009-9861 A International Publication No. WO2013 / 005638 Japanese Patent No. 4517910 JP 2002-270891 A JP 2004-031350 A Special Table 2005-535121 JP 2009-158478 A

  The present invention has been made in view of the problems and demands of the conventional techniques as described above, and an object of the present invention is to provide a plurality of organic light emitting materials formed on an organic EL layer that emits white light. In the organic light emitting diode, the organic light emitting diode capable of selectively improving the light extraction efficiency of the organic light emitting material having a low internal quantum efficiency without reducing the lifetime of each organic light emitting material, a method for manufacturing a substrate for an organic light emitting diode, and an image A display device and a lighting device are to be provided.

  In order to achieve the above object, the present invention is an organic light emitting diode that emits white light by mixing light of different wavelengths, and improves light extraction efficiency without shortening the lifetime of the organic light emitting material. Specifically, a fine structure is introduced inside the element of the organic light emitting diode.

In particular, by introducing a two-dimensional grating structure that acts as a diffraction grating optimized for extracting the surface plasmon mode having the largest energy among waveguide modes that cause energy loss in the element, The waveguide mode extraction efficiency is maximized.

That is, the organic light emitting diode according to the present invention includes at least a metal layer made of a metal material and a transparent metal layer made of a transparent conductive material and a metal layer that can transmit light, or only a metal layer made of a metal material. An organic EL layer including a conductive layer, a second conductive layer made of a transparent conductive material, and a plurality of light-emitting layers each containing an organic light-emitting material that emits light of different wavelengths, and the first conductive layer and the second conductive layer The conductive layer and the organic EL layer are stacked in a predetermined order on the organic light emitting diode substrate so that the organic EL layer is positioned between the first conductive layer and the second conductive layer. In the organic light emitting diode, a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged two-dimensionally on a predetermined surface on which the adjacent layer of the metal layer of the first conductive layer is formed. Form, among the plurality of organic light emitting material, an internal quantum efficiency and the at least one of the lifetime of the organic light-emitting material corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the propagation constant of the surface plasmon generated on the predetermined surface of the metal layer to k _1, the distance between the centers P of the projections or recesses adjacent the projections or recesses formed in said predetermined plane, ( The value in the range of the formula (1), and P ₀ in the formula (1) satisfies the formula (2) and forms a square lattice structure as the two-dimensional lattice structure when the triangular lattice structure is formed as the two-dimensional lattice structure. Is formed so as to satisfy the expression (3).

  The organic light-emitting diode according to the present invention is the above-described organic light-emitting diode, wherein the metal material forming the metal layer in the first conductive layer is an alloy of Ag or Al or Ag content of 10% by mass or more. This is an alloy having an Al content of 10% by mass or more.

  The organic light emitting diode according to the present invention is the above organic light emitting diode, wherein the depth of the concave portion and the height of the convex portion are 15 to 180 nm.

  The method for manufacturing an organic light emitting diode substrate according to the present invention is a method for manufacturing an organic light emitting diode substrate for manufacturing an organic light emitting diode substrate used in the organic light emitting diode described above, wherein predetermined particles are two-dimensionally formed. A plurality of convex portions or concave portions are periodically formed on the surface on which the first conductive layer, the second conductive layer, and the organic EL layer are laminated by a dry etching method using a close-packed particle single layer film as an etching mask. A two-dimensional lattice structure arranged two-dimensionally is formed.

  The method for manufacturing an organic light emitting diode substrate according to the present invention is a method for manufacturing an organic light emitting diode substrate for manufacturing an organic light emitting diode substrate used in the organic light emitting diode described above, wherein predetermined particles are two-dimensionally formed. A mold with a two-dimensional lattice structure in which a plurality of convex or concave portions are periodically arranged in two dimensions is produced by dry etching using the closest packed particle monolayer film as an etching mask, and formed on the mold. A two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in a two-dimensional manner is transferred, and a plurality of the convex portions or concave portions are arranged on the surface on which the first conductive layer, the second conductive layer, and the organic EL layer are stacked. A two-dimensional lattice structure in which convex portions or concave portions are periodically arranged in two dimensions is formed.

The organic light emitting diode substrate manufacturing method described above is such that the predetermined particle diameter D satisfies the formula (4) in the organic light emitting diode substrate manufacturing method described above.

  In addition, an image display device according to the present invention includes the above-described organic light emitting diode.

  Moreover, the illuminating device by this invention is provided with the above-mentioned organic light emitting diode.

The organic light emitting diode substrate according to the present invention contains at least a cathode conductive layer including a metal layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths. An organic light emitting diode substrate in a top emission type organic light emitting diode that includes an organic EL layer including a light emitting layer and emits white light from the upper surface, and a surface on which the cathode conductive layer, the anode conductive layer, and the organic EL layer are stacked A plurality of convex portions are periodically arranged in a two-dimensional lattice structure, and at least one of the internal quantum efficiency and the lifetime of the organic light emitting material among the plurality of organic light emitting materials is the other raw on the upper surface or lower surface of the metal layer corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior organic luminescent materials The real part of the propagation constant of the surface plasmon When k ₁ that, center distance P of the convex portions adjacent in the convex portion formed on the surface, when forming a triangular lattice structure as the two-dimensional lattice structure, ( When the square lattice structure is formed as the two-dimensional lattice structure by satisfying the equation (5), the equation (6) is satisfied.

The organic light emitting diode substrate according to the present invention contains at least a cathode conductive layer including a metal layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths. An organic light emitting diode substrate in a top emission type organic light emitting diode that includes an organic EL layer including a light emitting layer and emits white light from the upper surface, and a surface on which the cathode conductive layer, the anode conductive layer, and the organic EL layer are stacked A plurality of recesses are periodically and two-dimensionally arranged to form a two-dimensional lattice structure, and among the plurality of organic light emitting materials, at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is the other raw on the upper surface or lower surface of the metal layer corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior organic luminescent materials That when the real part of the propagation constant of the surface plasmon and k _1, center distance P of the concave portions adjacent in recesses formed in said surface, when forming a triangular lattice structure as the two-dimensional lattice structure (5) When the formula is satisfied and a square lattice structure is formed as the two-dimensional lattice structure, the equation (6) is satisfied.

The organic light emitting diode substrate according to the present invention contains at least a cathode conductive layer including a metal layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths. An organic light emitting diode substrate in a bottom emission type organic light emitting diode that includes an organic EL layer including a light emitting layer and emits white light from the lower surface, and a surface on which the cathode conductive layer, the anode conductive layer, and the organic EL layer are stacked A plurality of convex portions are periodically arranged in a two-dimensional lattice structure, and at least one of the internal quantum efficiency and the lifetime of the organic light emitting material among the plurality of organic light emitting materials is the other surface Plastic occurring on the lower surface of the metal layer corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior organic luminescent material When the real part of the propagation constant of Mon and k _1, center distance P of the convex portions adjacent in the convex portion formed on the surface, when forming a triangular lattice structure as the two-dimensional lattice structure (5) When the formula is satisfied and a square lattice structure is formed as the two-dimensional lattice structure, the equation (6) is satisfied.

The organic light emitting diode substrate according to the present invention contains at least a cathode conductive layer including a metal layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths. An organic light emitting diode substrate in a bottom emission type organic light emitting diode that includes an organic EL layer including a light emitting layer and emits white light from the lower surface, and a surface on which the cathode conductive layer, the anode conductive layer, and the organic EL layer are stacked A plurality of recesses are periodically and two-dimensionally arranged to form a two-dimensional lattice structure, and among the plurality of organic light emitting materials, at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is the other surface Plastic occurring on the lower surface of the metal layer corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior organic luminescent materials When the real part of the propagation constant of Mon and k _1, center distance P of the concave portions adjacent in recesses formed in said surface, when forming a triangular lattice structure as the two-dimensional lattice structure, a (5) When satisfying and forming a square lattice structure as the two-dimensional lattice structure, the equation (6) is satisfied.

In addition, the organic light emitting diode according to the present invention is a light emitting device including at least a reflective layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths on a substrate. An organic EL layer including a layer, and a cathode conductive layer in which a semi-transparent metal layer made of a metal material and a transparent conductive layer made of a transparent conductive material are sequentially laminated, and is in contact with the transparent conductive layer of the semi-transmissive metal layer A top emission type organic light emitting diode that emits white light, in which a two-dimensional lattice structure in which a plurality of convex portions are periodically arranged in a two-dimensional manner is formed on the surface of the plurality of organic light emitting materials. of, on at least one of the lifetime of the internal quantum efficiency and an organic luminescent material, corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the propagation constant of the surface plasmon that occurs on the surface in contact with the transparent conductive layer of the reflecting layer and k _1, center distance P of the convex portions adjacent in the convex portion formed on the surface, When the triangular lattice structure is formed as the two-dimensional lattice structure, the equation (5) is satisfied, and when the square lattice structure is formed as the two-dimensional lattice structure, the equation (6) is satisfied.

In addition, the organic light emitting diode according to the present invention is a light emitting device including at least a reflective layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths on a substrate. An organic EL layer including a layer, and a cathode conductive layer in which a semi-transparent metal layer made of a metal material and a transparent conductive layer made of a transparent conductive material are sequentially laminated, and is in contact with the transparent conductive layer of the semi-transmissive metal layer A top emission type organic light emitting diode that emits white light, in which a two-dimensional lattice structure in which a plurality of recesses are periodically and two-dimensionally arranged is formed on the surface of the plurality of organic light emitting materials , on at least one of the lifetime of the internal quantum efficiency and an organic luminescent material, corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the propagation constant of the surface plasmon that occurs on the surface in contact with the transparent conductive layer of the reflecting layer and k _1, center distance P of the concave portions adjacent in recesses formed in said surface, said two When a triangular lattice structure is formed as a two-dimensional lattice structure, equation (5) is satisfied, and when a square lattice structure is formed as the two-dimensional lattice structure, equation (6) is satisfied.

In addition, the organic light emitting diode according to the present invention is a light emitting device including at least a reflective layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths on a substrate. An organic EL layer including a layer, and a cathode conductive layer in which a translucent metal layer made of a metal material and a transparent conductive layer made of a transparent conductive material are sequentially laminated, and is in contact with the organic EL layer of the transflective metal layer A top emission type organic light emitting diode that emits white light, in which a two-dimensional lattice structure in which a plurality of convex portions are periodically arranged in a two-dimensional manner is formed on the surface of the plurality of organic light emitting materials. of, on at least one of the lifetime of the internal quantum efficiency and an organic luminescent material, corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the reflecting layer of the organic EL layer and in contact with which the propagation constant of the surface plasmon generated on the surface and k _1, center distance P of the convex portions adjacent in the convex portion formed on the surface, When the triangular lattice structure is formed as the two-dimensional lattice structure, the equation (5) is satisfied, and when the square lattice structure is formed as the two-dimensional lattice structure, the equation (6) is satisfied.

In addition, the organic light emitting diode according to the present invention is a light emitting device including at least a reflective layer made of a metal material, an anode conductive layer made of a transparent conductive material, and a plurality of organic light emitting materials that emit light of different wavelengths on a substrate. An organic EL layer including a layer, and a cathode conductive layer in which a translucent metal layer made of a metal material and a transparent conductive layer made of a transparent conductive material are sequentially laminated, and is in contact with the organic EL layer of the transflective metal layer A top emission type organic light emitting diode that emits white light, in which a two-dimensional lattice structure in which a plurality of recesses are periodically and two-dimensionally arranged is formed on the surface of the plurality of organic light emitting materials , on at least one of the lifetime of the internal quantum efficiency and an organic luminescent material, corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the propagation constant of the surface plasmon that occurs on the surface in contact with the organic EL layer of the reflecting layer and k _1, center distance P of the concave portions adjacent in recesses formed in said surface, said two When a triangular lattice structure is formed as a two-dimensional lattice structure, equation (5) is satisfied, and when a square lattice structure is formed as the two-dimensional lattice structure, equation (6) is satisfied.

The organic light emitting diode according to the present invention includes, on a substrate, at least a cathode conductive layer made of a metal material, an organic EL layer including a light emitting layer containing a plurality of organic light emitting materials that emit light of different wavelengths, and a transparent An anode conductive layer made of a conductive material was sequentially laminated, and a two-dimensional lattice structure in which a plurality of convex portions were periodically arranged two-dimensionally was formed on the surface of the cathode conductive layer in contact with the organic EL layer. A top emission type organic light emitting diode that emits white light, wherein at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is inferior to other organic light emitting materials among the plurality of organic light emitting materials. The real part of the propagation constant of the surface plasmon generated on the surface of the cathode conductive layer corresponding to the peak wavelength λ ₁ of the emission spectrum of a predetermined organic light emitting material in contact with the organic EL layer is denoted by k ₁ . Then, when the triangular lattice structure is formed as the two-dimensional lattice structure, the center-to-center distance P between adjacent convex portions in the convex portion formed on the surface satisfies the formula (5) and is square as the two-dimensional lattice structure. When the lattice structure is formed, the expression (6) is satisfied.

The organic light emitting diode according to the present invention includes, on a substrate, at least a cathode conductive layer made of a metal material, an organic EL layer including a light emitting layer containing a plurality of organic light emitting materials that emit light of different wavelengths, and a transparent An anode conductive layer made of a conductive material is sequentially stacked, and a two-dimensional lattice structure in which a plurality of concave portions are periodically arranged in two dimensions is formed on the surface of the cathode conductive layer in contact with the organic EL layer. A top emission type organic light emitting diode that emits white light, wherein at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is inferior to the other organic light emitting materials among the plurality of organic light emitting materials. The real part of the propagation constant of the surface plasmon generated on the surface of the cathode conductive layer corresponding to the peak wavelength λ ₁ of the emission spectrum of the organic light emitting material in contact with the organic EL layer is denoted by k ₁ . Then, the center-to-center distance P between adjacent convex portions in the concave portion formed on the surface satisfies the formula (5) when forming the triangular lattice structure as the two-dimensional lattice structure, and the square lattice as the two-dimensional lattice structure. When the structure is formed, the expression (6) is satisfied.

Further, the organic light emitting diode according to the present invention includes, on a substrate, an organic EL layer including at least an anode conductive layer made of a transparent conductive material, and a light emitting layer containing a plurality of organic light emitting materials that emit light of different wavelengths, A cathode conductive layer made of a metal material is sequentially laminated, and a two-dimensional lattice structure in which a plurality of convex portions are periodically arranged in two dimensions is formed on the surface of the cathode conductive layer in contact with the organic EL layer. A bottom emission type organic light emitting diode that emits white light, wherein at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is inferior to other organic light emitting materials among the plurality of organic light emitting materials. The real part of the propagation constant of the surface plasmon generated on the surface of the cathode conductive layer corresponding to the peak wavelength λ ₁ of the emission spectrum of a predetermined organic light emitting material in contact with the organic EL layer is denoted by k ₁ . Then, when the triangular lattice structure is formed as the two-dimensional lattice structure, the center-to-center distance P between adjacent convex portions in the convex portion formed on the surface satisfies the formula (5) and is square as the two-dimensional lattice structure. When the lattice structure is formed, the expression (6) is satisfied.

Further, the organic light emitting diode according to the present invention includes, on a substrate, an organic EL layer including at least an anode conductive layer made of a transparent conductive material, and a light emitting layer containing a plurality of organic light emitting materials that emit light of different wavelengths, A cathode conductive layer made of a metal material is sequentially laminated, and a two-dimensional lattice structure in which a plurality of concave portions are periodically arranged two-dimensionally is formed on the surface of the cathode conductive layer in contact with the organic EL layer. A bottom emission type organic light emitting diode that emits white light, wherein at least one of the internal quantum efficiency and the lifetime of the organic light emitting material among the plurality of organic light emitting materials is inferior to other organic light emitting materials. The real part of the propagation constant of the surface plasmon generated on the surface of the cathode conductive layer corresponding to the peak wavelength λ ₁ of the emission spectrum of the organic light emitting material in contact with the organic EL layer is denoted by k ₁ . Then, when the triangular lattice structure is formed as the two-dimensional lattice structure, the center-to-center distance P between the adjacent concave portions in the concave portion formed on the surface satisfies the formula (5) and the square lattice structure as the two-dimensional lattice structure. Is formed so as to satisfy the expression (6).

  In the organic light emitting diode according to the present invention, in the organic light emitting diode described above, the metal material forming the cathode conductive layer has an Ag or Al or Ag content of 10 mass% or more, or an Al content of 10 The alloy is made to be at least mass%.

  The method for producing an organic light emitting diode substrate according to the present invention is a method for producing an organic light emitting diode substrate for producing an organic light emitting diode substrate as described above, wherein a single particle in which predetermined particles are two-dimensionally closely packed. A two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged two-dimensionally is formed on the surface by a dry etching method using a layer film as an etching mask.

  The method for producing an organic light emitting diode substrate according to the present invention is a method for producing an organic light emitting diode substrate for producing an organic light emitting diode substrate as described above, wherein a single particle in which predetermined particles are two-dimensionally closely packed. A mold having a structure in which a plurality of convex portions or concave portions are periodically arranged two-dimensionally is produced by a dry etching method using a layer film as an etching mask, and the plurality of convex portions or concave portions formed on the mold are formed. A two-dimensional lattice structure periodically arranged in two dimensions is transferred to form a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in two dimensions on the surface. .

  The organic light emitting diode manufacturing method according to the present invention is an organic light emitting diode manufacturing method for manufacturing the above organic light emitting diode, wherein a plurality of convex portions or concave portions are periodically arranged in a two-dimensional manner on the surface of the substrate. The reflection layer, the anode conductive layer, and the surface of the substrate on which the two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in two dimensions is formed. An organic EL layer and the cathode conductive layer are sequentially laminated.

  The organic light emitting diode manufacturing method according to the present invention is an organic light emitting diode manufacturing method for manufacturing the above organic light emitting diode, wherein a plurality of convex portions or concave portions are periodically arranged in a two-dimensional manner on the surface of the substrate. The cathode conductive layer, the organic EL layer, and the surface of the substrate on which a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in two dimensions is formed, The anode conductive layer is sequentially laminated.

  The organic light emitting diode manufacturing method according to the present invention is an organic light emitting diode manufacturing method for manufacturing the above organic light emitting diode, wherein a plurality of convex portions or concave portions are periodically arranged in a two-dimensional manner on the surface of the substrate. The anode conductive layer, the organic EL layer, and the surface of the substrate on which a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in two dimensions is formed, The cathode conductive layer is sequentially laminated.

  The organic light emitting diode manufacturing method according to the present invention is the above-described organic light emitting diode manufacturing method, wherein the metal material forming the cathode conductive layer is Ag or Al or an alloy having an Ag content of 10% by mass or more. An alloy having an Al content of 10% by mass or more is used.

  Moreover, the manufacturing method of the organic light emitting diode according to the present invention is such that in the above-described manufacturing method of the organic light emitting diode, the depth of the concave portion and the height of the convex portion are set to 15 to 180 nm.

  Further, the organic light emitting diode manufacturing method according to the present invention is the above-described organic light emitting diode manufacturing method, wherein the substrate is formed by a dry etching method using a particle single layer film in which predetermined particles are two-dimensionally closely packed as an etching mask. A two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically and two-dimensionally arranged is formed on the surface.

  In addition, the organic light emitting diode manufacturing method according to the present invention includes a plurality of dry etching methods using a single particle layer film in which predetermined particles are two-dimensionally closely packed in the organic light emitting diode manufacturing method. Produces a template with a structure in which convex parts or concave parts are periodically arranged in two dimensions, and transfers a two-dimensional lattice structure in which a plurality of convex parts or concave parts formed in the mold are periodically arranged in two dimensions Thus, a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged two-dimensionally is formed on the surface of the substrate.

Moreover, the manufacturing method of the organic light emitting diode according to the present invention is such that in the above-described manufacturing method of the organic light emitting diode, the particle diameter D satisfies the expression (4) in the predetermined particles.

  Since the present invention is configured as described above, in the plurality of organic light emitting materials formed in the organic EL layer that emits white light, the internal quantum efficiency is reduced without reducing the lifetime of each organic light emitting material. The light extraction efficiency of an organic light emitting material having a low level can be selectively improved.

FIG. 1 is a schematic configuration explanatory view showing an organic light emitting diode according to a first embodiment of the present invention. FIG. 2A is a schematic perspective view illustrating the fine structure formed on the back surface of the cathode conductive layer in the organic light emitting diode according to the present invention, and FIG. 2B illustrates the organic light emitting diode according to the present invention. It is a schematic structure perspective explanatory view showing the fine structure formed in the surface of the substrate in. FIG. 3 is an explanatory view showing a dipole in the layer structure of the organic light emitting diode. FIG. 4 is a graph illustrating energy dissipation of a dipole in the organic light emitting diode according to the first embodiment of the present invention. FIG. 5 is a graph illustrating energy dissipation of a dipole in an organic light emitting diode according to the second embodiment of the present invention. FIG. 6A shows an explanatory diagram in which the surface of the substrate after the dry etching process is observed with an AFM, and FIG. 6B is a cross-sectional view taken along the line AA of FIG. It is shown. FIG. 7 is a schematic structural explanatory view showing an organic light emitting diode according to a third embodiment of the present invention. FIG. 8 is a graph showing energy dissipation of a dipole in an organic light emitting diode according to the third embodiment of the present invention. FIG. 9 is a schematic structural explanatory view showing an organic light emitting diode according to a fourth embodiment of the present invention. FIG. 10 shows Examples 1, 2, 3 and 4 as organic light emitting diodes according to the first, second, third and fourth embodiments of the present invention and Comparative Examples 1, 2, 3 as organic light emitting diodes according to the prior art. 4 is a table showing measurement results obtained by measuring current efficiency and power efficiency in unit currents of 4 and 4; FIG. 11 is a graph showing energy dissipation of a dipole in an organic light emitting diode according to the fourth embodiment of the present invention.

Hereinafter, embodiments of an organic light emitting diode, a method for manufacturing an organic light emitting diode substrate, an image display device, and an illumination device according to the present invention will be described in detail with reference to the accompanying drawings.

First, a first embodiment of an organic light emitting diode according to the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic configuration explanatory view showing an example of the organic light emitting diode according to the first embodiment of the present invention.

  In the description of the organic light emitting diode 10 shown in FIG. 1, for convenience of explanation, the upper surface in the height direction of each layer constituting the organic light emitting diode 10 is appropriately referred to as the upper surface, and the lower side in the height direction of each layer. The surface of is appropriately referred to as the lower surface.

Further, in the following description, as long as the present invention is used, the structure and method of the target organic light emitting diode are not necessarily limited.

  The organic light emitting diode 10 shown in FIG. 1 is an organic light emitting diode of a type generally referred to as a three-wavelength cathode top emission type, and includes a reflective layer 22, an anode conductive layer 14, an organic EL layer 16 on a substrate 12. A cathode conductive layer 18 is sequentially laminated.

  A voltage can be applied to the anode conductive layer 14 and the cathode conductive layer 18 by a power source 20.

  In this organic light emitting diode 10, when voltage is applied to the anode conductive layer 14 and the cathode conductive layer 18, holes are injected from the anode conductive layer 14 into a light emitting layer 16-3 (described later) in the organic EL layer 16. In addition, electrons are injected from the cathode conductive layer 18 into the light emitting layer 16-3 (described later) in the organic EL layer 16, and light generated in the organic EL layer 16 is extracted from the cathode conductive layer 18 side. .

The organic light emitting diode 10 according to the first embodiment of the present invention is an organic light emitting diode called a three-wavelength cathode top emission type, and the light emitting layer 16-3 includes three organic light emitting materials ( A light emitting layer 16-3a, a light emitting layer 16-3b, and a light emitting layer 16-3c, the details of which will be described later). Hereinafter, when the light emitting layer 16-3 is collectively described and there is no problem, the three layers are described as the light emitting layer 16-3.

  The reflective layer 22 is a layer provided so as to reflect light from the organic EL layer 16 so that the light is not extracted from the substrate 12.

  Therefore, the reflective layer 22 is made of a metal material that reflects visible light, and is made of, for example, Ag or Al.

  In addition, the thickness of the reflective layer 22 is preferably, for example, 100 to 200 nm.

In addition, the thickness of each layer which comprises the organic light emitting diode 10 containing the reflection layer 22 can be measured with a spectroscopic ellipsometer, a contact-type level difference meter, or an atomic force microscope (AFM).

  The anode conductive layer 14 is connected to the anode of the power source 20 and is made of a transparent conductive material that transmits visible light. Such a transparent conductive material is not particularly limited, and a known transparent conductive material can be used.

  Specifically, the transparent conductive material used for the anode conductive layer 14 includes indium tin oxide (Indium Tin Oxide (ITO)), indium zinc oxide (Indium Zinc Oxide (IZO)), and zinc oxide (Zinc Oxide). (ZnO)) or zinc tin oxide (Zinc Tin Oxide (ZTO)).

Further, the thickness of the anode conductive layer 14 is preferably, for example, 50 to 200 nm.

  The organic EL layer 16 transports holes injected from the power source 20 to the hole injection layer 16-1 and the holes injected in the hole injection layer 16-1 to the light emitting layer 16-3 described later. Hole transport layer 16-2 that blocks electrons from -3, and a plurality of organic light emitting materials that emit light of different wavelengths, and holes transported from the hole transport layer 16-2 and electron transport described later A light emitting layer 16-3 that emits light by combining with electrons transported from the layer 16-4, and an electron injected in an electron injection layer 16-5, which will be described later, are transported to the light emitting layer 16-3, and the light emitting layer The electron transport layer 16-4 blocks holes from 16-3 and the electron injection layer 16-5 into which electrons are injected from the power supply 20.

The light emitting layer 16-3 includes a light emitting layer 16-3a made of an organic light emitting material that emits light of a predetermined wavelength, and an organic light emitting device that emits light having a wavelength different from that of the organic light emitting material forming the light emitting layer 16-3a. A light emitting layer 16-3b made of a material and a light emitting layer 16-3c made of an organic light emitting material that emits light of a wavelength different from that of the organic light emitting material forming the light emitting layers 16-3a and 16-3b. ing. The light emitting layers 16-3a, 16-3b, and 16-3c each emit light, and the organic light emitting material to be used is selected so that white light is emitted from the light emitting layer 16-3.

  The organic EL layer 16 is formed on the anode conductive layer 14 with a hole injection layer 16-1, a hole transport layer 16-3, a light emitting layer 16-3 (light emitting layer 16-3a, light emitting layer 16-3b, light emitting layer 16). -3c), an electron transport layer 16-4, and an electron injection layer 16-5 are laminated in this order.

  Note that these layers may have a single role or may have two or more roles. For example, the electron transport layer 16-4 and the light emitting layer 16-3c may be combined into one layer. It is something that can be done.

That is, the organic EL layer 16 may be at least a layer including the light emitting layer 16-3 containing an organic light emitting material, and may be composed of only the light emitting layer 16-3. Layers other than 16-3 are included. Such a layer other than the light emitting layer 16-3 may be composed of an organic material or an inorganic material as long as the function of the light emitting layer 16-3 is not impaired.

  Here, the material constituting each layer of the organic EL layer 16 is not particularly limited, and any known organic light emitting material constituting the light emitting layer of the organic EL can be used so far, for example, it generates fluorescence or phosphorescence. An organic compound that generates fluorescence and phosphorescence, a compound obtained by doping the organic compound with another substance (host material), a compound obtained by doping the organic compound with a doping material, and the like.

  Further, as an organic compound that generates fluorescence or phosphorescence, and an organic compound that generates fluorescence and phosphorescence, a pigment system, a metal complex type, a polymer system, and the like are known, and any of them may be used.

That is, as a material constituting the light emitting layer 16-3 (that is, the light emitting layers 16-3a, 16-3b, and 16-3c), an organic light emitting material is used. As such an organic light emitting material, for example, Specific examples of the dye system include 1,4-bis [4- (N, N-diphenylaminostyrylbenzene)] (DPAVB), 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H. , 11H-10- (2-benzothiazolyl) quinolizine [9,9a, 1-gh] (C545T), 4-4′-bis (2,2-diphenyl-ethen-1-yl) biphenyl, which is a distilarylene derivative. (DPVBi). As specific examples of the metal complex system, Tris [1-phenylisoquinoline-C2, N] iridium (III) (Ir (piq) ₃ ), Bis [2- (2-benzoxazolyl) phenolate] Zinc (II) (ZnPBO) Etc.

  In addition, organic materials are generally used as materials constituting the hole injection layer 16-1, the hole transport layer 16-2, and the electron transport layer 16-4.

As a material constituting the hole injection layer 16-1, for example, 4,4 ′, 4 ″ -tris (N, N-2naphthylphenylamino) triphenylamine (2-TNATA), 1,4,5,8,9,12− Examples thereof include compounds such as hexaazatriphenylenehexacarbonitrile (HAT-CN) and molybdenum oxide (MoO _x , x = 1 to 3).

  Examples of the material constituting the hole transport layer 16-2 include N, N′-diphenyl-N, N′-bis (1-naphthyl)-(1-1′-biphenyl) -4,4′-. Examples thereof include aromatic amine compounds such as diamine (NPD), copper phthalocyanine (CuPc), and N, N′-Diphenyl-NN—di (m-tolyl) benzidine (TPD).

Furthermore, examples of the material constituting the electron transport layer 16-4 include 2,5-Bis (1-naphthyl) -1,3,4-oxadiazole (BND), 2- (4-tert-Butylphenyl) -5. - (4-biphenylyl) -1,3,4- oxadiazole (PBD) oxa diol compound such as, Tris (8-quinolinolate) aluminium (Alq 3) and metal complex compounds such as.

  Furthermore, as a material which comprises the electron injection layer 16-5, lithium fluoride (LiF) etc. are mentioned, for example.

  When such an electron injection layer 16-5 is provided between the electron transport layer 16-4 and the cathode conductive layer 18, a difference in work function can be reduced, and electrons are transferred from the cathode conductive layer 18 to the electron transport layer 16-4. Will be easier to migrate.

  If a magnesium alloy such as Mg / Ag = 10/90 is used as the cathode conductive layer 18, the electron injection effect can be obtained without providing the electron injection layer 16-5.

The total thickness of the organic EL layer 16 is preferably 30 to 500 nm, for example.

  The cathode conductive layer 18 includes a metal layer 18-1 connected to the cathode of the power supply 20 and a transparent conductive layer 18-2. The metal layer 18-1 and the transparent conductive layer are formed on the organic EL layer 16. 18-2 are sequentially laminated.

  The metal layer 18-1 is made of Ag, an alloy with an Ag content of 10% or more, Al or an alloy with an Al content of 10% or more. Examples of the alloy include the above-described Mg / Ag = 10 / Examples include magnesium alloys such as 90.

  The thickness of the metal layer 18-1 is preferably 10 to 30 nm, for example, and can transmit light from the organic EL layer 16.

  The transparent conductive layer 18-2 is made of a transparent conductive material that transmits visible light, similarly to the anode conductive layer 14, and the transparent conductive material is not particularly limited and may be a known transparent conductive material. Can be used.

  Specifically, as the transparent conductive material used for the transparent conductive layer 18-2, indium tin oxide (Indium Tin Oxide (ITO)), indium zinc oxide (Indium Zinc Oxide (IZO)), zinc oxide ( Zinc Oxide (ZnO)) or zinc-tin oxide (Zinc Tin Oxide (ZTO)).

  Here, the organic light emitting diode 10 is a top emission type in which light is extracted from the cathode conductive layer 18 side.

  For this reason, in order to allow the light from the organic EL layer 16 to be transmitted, the metal layer 18-1 is formed as a thin layer.

  At this time, if the cathode conductive layer 18 is only the metal layer 18-1, the volume resistance is increased because the metal layer 18-1 is a thin layer.

  For this reason, in the organic light emitting diode 10, the conductivity is improved by providing the transparent conductive layer 18-2 as the auxiliary electrode layer together with the metal layer 18-1 as the cathode conductive layer 18.

The thickness of the transparent conductive layer 18-2 is preferably 50 to 200 nm, for example.

  The substrate 12 may be a transparent body that transmits visible light or an opaque body that does not transmit visible light. The material constituting the substrate 12 may be an inorganic material or an organic material, or a combination thereof. .

  Specifically, as the material constituting the substrate 12, the transparent inorganic material includes quartz glass, non-alkali glass, alkali glass such as soda lime glass, various glasses such as white plate glass, transparent inorganic minerals such as mica, etc. As an opaque inorganic material, metals such as aluminum, nickel, and stainless steel, various ceramics, and the like can be given.

  Examples of the organic material include resin films such as cycloolefin films and polyester films, and fiber reinforced plastic materials in which fine fibers such as cellulose nanofibers are mixed in the resin film. As for the organic material, both a transparent body and an opaque body can be used.

  Furthermore, on the surface 12a (that is, the upper surface of the substrate 12) on the side where the anode conductive layer 14 of the substrate 12 is laminated, a structure in which a plurality of convex portions 12b are periodically arranged in two dimensions (hereinafter, “ A structure that is periodically arranged two-dimensionally is referred to as a “two-dimensional lattice structure” as appropriate).

  Then, the reflective layer 22, the anode conductive layer 14, the organic EL layer 16, and the cathode conductive layer 18 are sequentially laminated on the substrate 12 on which the two-dimensional lattice structure is formed, so that the surface of each layer (that is, the upper surface of each layer). And the surface opposite to the side on which the substrate 12 is located.), A two-dimensional lattice structure with a plurality of convex portions similar to the surface 12a of the substrate 12 is formed.

  In addition, the back surface of each layer (that is, the lower surface of each layer and the surface on which the substrate 12 is located) has a structure in which the structure formed on the surface 12a of the substrate 12 is inverted, that is, a plurality of recesses. A periodically arranged structure, that is, a two-dimensional lattice structure with a plurality of recesses is formed.

  Specifically, focusing on the metal layer 18-1, the surface 18-1a of the metal layer 18-1 (that is, the upper surface of the metal layer 18-1 and the surface on the side where the transparent conductive layer 18-2 is located). In other words, a two-dimensional lattice structure equivalent to the plurality of projections 12b formed on the surface 12a of the substrate 12 is formed to form a plurality of projections.

  On the other hand, on the back surface 18-1c of the metal layer 18-1 (that is, the bottom surface of the metal layer 18-1, the surface on the side where the organic EL layer 16 is located, and the back surface 18a of the cathode conductive layer 18). Is a structure in which the structure formed on the surface 12a of the substrate 12 is inverted, that is, a structure in which a plurality of recesses 18b are periodically arranged in two dimensions, that is, a two-dimensional lattice structure is formed by the plurality of recesses 18b. It becomes.

  Such a two-dimensional lattice structure is designed to enhance the wavelength of an organic light emitting material having a low internal quantum efficiency or a short lifetime (for example, a wavelength of 470 nm (blue) in white). Surface plasmons excited in the metal layer 18-1 are extracted as propagating light.

  Here, when light is emitted from the light emitting molecules in the light emitting layer 16-3, near-field light is generated very close to the light-emitting layer 16-3, and the near-field light is emitted from the light-emitting layer 16-3 and the metal layer 18-1. Therefore, the surface 18-1a and the back 18-1c of the metal layer 18-1 are converted into propagation type surface plasmons.

  Propagation-type surface plasmon on the surface of metal has a surface electromagnetic field accompanied by free-electron density waves generated by incident electromagnetic waves (such as near-field light).

  In the case of a surface plasmon existing on a flat metal surface, the dispersion curve of the surface plasmon and the dispersion curve of light (spatial propagation light) do not intersect with each other, so that the energy of the surface plasmon cannot be extracted as light. On the other hand, when a lattice structure is formed on the metal surface, the dispersion curve of the surface plasmon diffracted by the lattice structure intersects with the dispersion curve of the spatial propagation light, and the surface plasmon is extracted as radiation light. Can do.

  Thus, by providing the two-dimensional lattice structure, the energy of light lost as surface plasmons can be extracted. The energy thus extracted is emitted from the metal layer 18-1 in the cathode conductive layer 18 as radiation light.

  At this time, the light radiated from the metal layer 18-1 has high directivity, and if it is appropriately designed, most of the light is a surface 18c of the cathode conductive layer 18 that is a light extraction surface (that is, the upper surface of the cathode conductive layer 18). Yes, the surface of the transparent conductive layer 18-2 opposite to the side where the metal layer 18-1 is located.

  Therefore, in the organic light emitting diode 10, light whose internal quantum efficiency is low or the strength of the organic light emitting material having a short lifetime is emitted from the light extraction surface. Even if it is an organic light emitting material having a relatively short lifetime, it is possible to improve light extraction efficiency without applying an excessive applied voltage and shortening the lifetime.

  In such a two-dimensional lattice structure, for example, when focusing on the cathode conductive layer 18, a recess formed on the back surface 18 a (that is, the bottom surface of the cathode conductive layer 18 and the back surface 18-1 c of the metal layer 18-1). 18b is arranged two-dimensionally, so that it is one-dimensional (that is, the arrangement direction is one direction, for example, a structure in which a plurality of grooves are arranged in one direction). The extraction efficiency is higher than that.

As a preferable specific example of such a two-dimensional lattice structure, the arrangement direction is two directions and the intersection angle is 90 ° (square lattice), the arrangement direction is three directions and the intersection angle is 60 ° ( A triangular lattice (also referred to as a hexagonal lattice)), and a triangular lattice structure is particularly desirable. This is because the more the arrangement direction, the more the conditions for obtaining the diffracted light, and the surface plasmon can be diffracted with high efficiency.

  In order to form a triangular lattice structure in such a two-dimensional lattice structure, a particle monolayer film in which particles are arranged in a two-dimensional hexagonal close-packed configuration is formed, and dry etching is performed using the particle monolayer film as an etching mask. Thus, it can be easily obtained. A method of forming a triangular lattice structure using such a particle single layer film will be described later.

  The depth D1 of the recess 18b is 15 nm ≦ D1 ≦ 180 nm, preferably 30 nm ≦ D1 ≦ 100 nm. When D1 <15 nm or D1> 180 nm, the effect of improving the light extraction efficiency becomes insufficient.

  The range of the depth D1 of the recess 18b described above is based on the following reason.

  That is, when the depth D1 of the recess 18b is less than 15 nm (that is, when D1 <15 nm), it is impossible to generate a sufficient surface plasmon diffracted wave as a two-dimensional lattice structure, and the surface plasmon is used as radiation light. The effect of taking out decreases.

  Further, when the depth D1 of the recess 18b exceeds 180 nm (that is, when D1> 180 nm), the surface plasmon begins to have a localized type property and is no longer a propagation type, so that radiation light can be extracted. Efficiency is reduced. Furthermore, in this case, when the reflective layer 22, the anode conductive layer 14, the organic EL layer 16, and the cathode conductive layer 18 of the organic light emitting diode 10 are sequentially laminated, the anode conductive layer 14 and the cathode conductive layer are sharply uneven. The possibility of short-circuiting with the layer 18 is increased, which is not preferable.

  Furthermore, since the depth D1 of the concave portion 18b is the same as the height H1 of the convex portion 12b formed on the surface 12a of the substrate 12, the height of the convex portion 12b is measured indirectly by AFM. It can be quantified.

  For example, first, an AFM image was acquired for one randomly selected 5 μm × 5 μm region in a two-dimensional lattice structure, and then a line was drawn in the diagonal direction of the acquired AFM image, and intersected with this line The maximum height of the convex part 12b is calculated independently. Then, the average value of the height of the calculated convex part 12b is calculated. This process is similarly executed for a total of 25 randomly selected 5 μm × 5 μm regions, and the average value of the convex portions 12b in each region is calculated, and the average value in the obtained 25 regions is further averaged. The obtained value is defined as the height of the convex portion 12b.

The shape of the convex portion 12b is not particularly limited, and examples thereof include a cylindrical shape, a cone shape, a truncated cone shape, a sine wave shape, a dome shape, and a derivative shape based on them.

  Next, a method for manufacturing the organic light emitting diode 10 will be described. The method for manufacturing the organic light emitting diode 10 is not particularly limited, but preferably, the reflective layer 22 is formed on the surface 12a of the substrate 12 in which a plurality of convex portions 12b are formed on the surface 12a in a two-dimensional lattice structure. And anode conductive layer 14, organic EL layer 16 (hole injection layer 16-1, hole transport layer 16-2, light emitting layer 16-3 (light emitting layers 16-3a, 16-3b, 16-3c), electron transport) Layer 16-4, electron injection layer 16-5) and cathode conductive layer 18 (metal layer 18-1, transparent conductive layer 18-2) are sequentially laminated.

  In this case, the two-dimensional lattice structure by the plurality of recesses 18b formed on the back surface 18a of the cathode conductive layer 18 (that is, the bottom surface of the cathode conductive layer 18 and the back surface 18-1c of the metal layer 18-1) is as follows. This corresponds to a two-dimensional lattice structure formed by a plurality of convex portions 12b formed on the surface 12a of the substrate 12 (see FIGS. 2A and 2B).

  That is, the center-to-center distance P1 between adjacent recesses 18b in the plurality of recesses 18b formed on the back surface 18a of the cathode conductive layer 18 (hereinafter referred to as “center-to-center distance P1 between adjacent recesses 18b” is referred to as “center of the recesses 18b”). Is referred to as an inter-distance P1 ”). The center-to-center distance P2 between the adjacent convex portions 12b of the plurality of convex portions 12b formed on the surface 12a of the substrate 12 (hereinafter referred to as“ between adjacent convex portions 12b ”). The center-to-center distance P2 "is referred to as" the center-to-center distance P2 of the convex part 12b "), and the depth D1 of the concave part 18b matches the height H1 of the convex part 12b.

  For this reason, the center of the concave portion 18b formed on the back surface 18a of the cathode conductive layer 18 is measured by measuring the distance P2 between the centers of the convex portions 12b formed on the front surface 12a of the substrate 12 and the height H1 of the convex portions 12b. The distance P1 and the depth D1 of the recess 18b can be measured.

  The center-to-center distance P1 of the recesses 18b can be indirectly measured by measuring the center-to-center distance P2 of the projections 12b by a laser diffraction method, and the depth D1 of the recesses 18b is determined by the projections The height H1 of 12b can be indirectly measured by measuring with an AFM.

Hereinafter, the manufacturing method of the organic light emitting diode 10 will be described in detail.

  First, a method for producing a two-dimensional lattice structure using a plurality of convex portions 12b formed on the surface 12a of the substrate 12 includes, for example, electron beam lithography, mechanical cutting, laser processing, two-beam interference exposure, reduced exposure, and the like. Can be used. In addition, if the original plate is prepared in advance, the fine structure can be transferred and duplicated by the nanoimprint method.

  Among these methods, methods other than the two-beam interference exposure and the nanoimprint method are not suitable for manufacturing a large-area periodic grating structure, and thus are limited in terms of industrial use.

  In addition, two-beam interference exposure can produce a small area to some extent, but in the case of a large area with a side of several centimeters or more, vibration, wind, thermal contraction, expansion, air fluctuation, wavelength for the entire optical setup It is extremely difficult to produce a uniform and accurate periodic grating structure due to various disturbance factors such as fluctuations.

  Therefore, as a method for producing a two-dimensional lattice structure using a plurality of convex portions 12b formed on the surface 12a of the substrate 12 in the organic light emitting diode 10, a dry etching method using a particle single layer film as an etching mask (hereinafter referred to as “particle single particle”). The “method of performing dry etching using the layer film as an etching mask” is preferably referred to as “etching method using particle single layer film”.

  In this method, a single-layer film of particles having a primary particle size equal to or smaller than the emission wavelength on the surface 12a of the substrate 12 is produced using the principle of the Langmuir-Blodgett method (hereinafter referred to as “LB method” as appropriate). This is a method utilizing the fact that a two-dimensional close-packed lattice in which the control of the particle spacing is performed with high accuracy is obtained. Such a method is disclosed in, for example, Patent Document 7 described above.

  In this particle single layer film, since the particles are two-dimensionally closely packed, the substrate original plate (that is, the substrate 12 before forming the two-dimensional lattice structure) is used as an etching mask. By dry etching, a highly accurate triangular lattice (hexagonal lattice) two-dimensional lattice structure can be formed.

  Since the two-dimensional lattice structure on the back surface 18a of the cathode conductive layer 18 formed using a substrate having such a two-dimensional lattice structure is also highly accurate, this method can be used in a large area. Even if it exists, the diffracted wave of surface plasmon can be obtained with high efficiency, and the high-intensity organic light emitting diode 10 with improved light extraction efficiency can be obtained.

  In this etching method using the particle single layer film, a coating step of coating the surface of the substrate original plate with the particle single layer film, and a step of dry etching the substrate original plate using the particle single layer film as an etching mask (dry etching step). ), A two-dimensional lattice structure with a plurality of convex portions 12b is formed on the substrate 12.

  Hereinafter, the covering step and the dry etching step will be described in detail.

(1) Coating step The coating step of coating the surface of the substrate original plate with a particle monolayer film is a liquid for expanding particles on the liquid surface in the water tank (hereinafter referred to as “for expanding particles on the liquid surface”). "Liquid" is appropriately referred to as "lower layer liquid"), and a dispersion liquid in which particles are dispersed in an organic solvent is dropped onto the liquid surface of the lower layer liquid, and the organic solvent is volatilized from the dropped dispersion liquid. This is carried out by performing a particle single layer film forming step of forming a particle single layer film composed of particles on the liquid surface of the lower layer liquid and a transition step of transferring the particle single layer film onto the substrate 12.

  In the following description, a case where a hydrophilic liquid is used as the lower layer liquid and a hydrophobic liquid is used as the organic solvent and particles in the dispersion liquid will be described. In addition, you may use a hydrophobic liquid as a lower layer liquid, In that case, a hydrophilic thing is used as a particle.

(1-1) Particle Single Layer Film Formation Step In this step, first, the surface is hydrophobic in an organic solvent having high volatility (for example, chloroform, methanol, ethanol, methyl ethyl ketone, methyl isobutyl ketone, hexane, etc.). The dispersion liquid is prepared by adding the particles. In addition, a water tank is prepared, and water as a lower layer liquid (hereinafter, water as the lower layer liquid is appropriately referred to as “lower layer water”) is put into the water tank.

  And if the prepared dispersion liquid is dripped at the liquid level of the lower layer water stored by the water tank, the particle | grains in a dispersion liquid will expand | deploy on the liquid level of lower layer water with a dispersion medium. Thereafter, the organic solvent as the dispersion medium is volatilized to form a particle monolayer film in which the particles are two-dimensionally closely packed.

  The particle size of the particles used for forming the particle single layer film is set in consideration of the center-to-center distance P2 of the projections 12b to be formed. That is, the center-to-center distance P2 of the protrusions 12b formed on the surface 12a of the substrate 12 is determined by the particle size of the particles to be used, and the center-to-center distance P2 of the protrusions 12b is determined. The inter-distance P1 is determined.

Regarding the particle size of the particles forming this particle monolayer film, at least one of the internal quantum efficiency and the lifetime of the organic light emitting material is a peak wavelength of the emission spectrum of a predetermined organic light emitting material inferior to other organic light emitting materials. That is, the wave number (propagation constant) of the surface plasmon generated in the cathode conductive layer corresponding to the peak wavelength of the emission spectrum of the organic light emitting material to be extracted is calculated, and then the lattice pitch (that is, the recess 18b) is calculated from the wave number of the surface plasmon. The distance between the centers P1 and corresponding to the distance P2 between the centers of the protrusions 12a), and finally the particle size is calculated.

  Here, a specific method for determining the particle diameter of the particles forming the particle monolayer film will be described with reference to FIG.

  First, how to obtain the wave number (propagation constant) of the surface plasmon corresponding to the light of wavelength λ will be described.

  The method for determining the wave number of the surface plasmon is the same as that for the layer structure of the organic light emitting diode in the case where there is no unevenness, and the concept of the organic light emitting diode is the same for both the bottom emission type and the top emission type.

  As shown in FIG. 3, when the organic light emitting diode is formed by laminating a plurality of layers from the first layer to the Jth layer from the substrate to the air, the first layer is constituted by the substrate, and The Jth layer is composed of air.

Here, the j-th layer is one of layers constituting the layers of organic light emitting diodes, and its thickness is assumed that d _j, also, its dielectric constant is assumed to be given by epsilon _j.

Then, the thickness dj of the _Jth layer becomes infinite. Further, the thickness d ₁ of the first layer may be infinite.

  Next, assuming that the M-th layer where j = M is a metal layer supporting surface plasmons, first, the propagation constant of the surface plasmons propagating through the interfaces on both sides of the M-th layer is obtained.

  Here, there are two surface plasmon modes that propagate through the interface of the metal layer.

  One is a mode in which energy is mainly concentrated at the interface between the (M−1) th layer and the Mth layer, which is a layer immediately below the Mth layer, and the other is a mode in which mainly the Mth and Mth layers. This mode concentrates on the interface with the (M + 1) th layer, which is the layer immediately above.

Hereinafter, the former M _- mode, will be referred latter as M ₊ mode. The propagation constant of surface plasmon in each of these modes can be obtained by solving the eigen equation of the system.

  In general, this eigen equation cannot be solved analytically, but can only be solved numerically using a nonlinear optimization technique. This calculation becomes more difficult as the total number of parameters increases.

  The propagation constant of surface plasmons is a complex number, and the above eigen equation accurately gives this complex propagation constant. However, since all that is needed here is the real part of the propagation constant of the surface plasmon, in this case, a method obtained by simple calculation can be applied.

  Propagation modes (surface plasmon mode and waveguide mode) possessed by the layer structure are characterized by propagation constants. This propagation constant relates to a component parallel to the interface (hereinafter referred to as an in-plane wave number) in the wave number of the propagation mode.

When a vibrating dipole is placed in this layer structure, the energy is dissipated in each mode of the layer structure. Since each mode has a different propagation constant, that is, an in-plane wave number, by examining the in-plane wave number dependence of the energy dissipated from the dipole, it is possible to know which propagation mode this layer structure has.

  Here, the specific calculation procedure of the in-plane wave number dependence of the dissipative energy of the dipole is as follows.

  First, it is assumed that one dipole is placed in an arbitrary layer. The layer in which this dipole is placed is defined as the Nth layer.

  Here, FIG. 3 shows a layer structure of an organic light emitting diode, and an explanatory diagram showing a dipole placed in the layer structure is shown in the Nth layer where j = N. .

In FIG. 3, a dipole is placed in the Nth layer, and arrows d ⁻ and d ⁺ indicate the distance from the dipole to the lower interface of the Nth layer and the upper interface of the Nth layer, respectively. Respectively.

  Further, it is assumed that the moment of the dipole is μ, and the dipole is oscillating at the extraction angular frequency ω.

When the above various values are used, the in-plane wavenumber (k _|| ) dependence of the energy dissipation of this dipole is given by the following equation (7) when the direction of the dipole is perpendicular to the interface. .

Also, when the direction of the dipole is parallel to the interface, it is given by the following equation (8).

Here, ε ₀ is the dielectric constant of vacuum. r _p ^- and at _{r s} ^over looked from N layer side, respectively (N-1) / plane wavenumber _{k ||} reflection coefficient of the p-polarized light and s-polarized light having at the N-interface (amplitude reflectance), _{r p} ^{+ And} r _s ⁺ are reflection coefficients of p-polarized light and S-polarized light having an in-plane wavenumber k _|| at the N / (N + 1) interface, respectively, viewed from the N layer side (see FIG. 3). Of course, these reflection coefficients include the effects of all layers up to the substrate or air. Also, _{k N} is wavevector of light waves in the N layer, it is given by ^{_{k N = ε N 1/2 ω /}} c. Further, k _N is a normal component of the wave vector of the light wave in the Nth layer, and is given by k _|| ² + k _z ² = k _N ² . C is the speed of light in vacuum.

The maximum of W _散 (k _|| ) and W _|| (k _|| ) corresponding to the in-plane wave number dependency of energy dissipation corresponds to each propagation mode, and the in-plane wave number giving the maximum corresponds to the propagation constant of the mode. Has become a department.

  Next, a method for identifying a surface plasmon mode from among a plurality of guided modes obtained by the above calculation will be described.

  The obtained waveguide modes include a TE waveguide mode, a TM waveguide mode, and a surface plasmon mode. Among them, the TE waveguide mode can be obtained only when the direction of the dipole is parallel to the interface.

  Therefore, the TM waveguide mode can be identified by comparing with the result calculated with the dipole direction perpendicular to the interface.

  Further, the surface plasmon mode exists only when a metal is present, and the number thereof matches the number of metal interfaces. Each metal interface has a one-to-one relationship mainly with each surface plasmon mode localized at the interface.

  Therefore, the surface plasmon mode is removed by replacing the metal layer with a suitable dielectric layer. The waveguide mode removed at this time can be identified as the surface plasmon mode.

  Which metal interface the obtained surface plasmon mode exists mainly can be determined as follows.

  That is, the dipole position is placed in the vicinity of each metal interface, the energy dissipation is calculated, and the peak heights corresponding to the surface plasmon modes are compared.

At this time, the metal interface located closest to the dipole giving the highest peak value is the interface where the surface plasmons are mainly localized.

  Next, a method for calculating the ratio of energy dissipation to each mode with respect to the total emission energy when the layer configuration of the organic EL element is given will be described.

  The in-plane wave number dependence of the dissipative energy of a dipole having a vertical and horizontal orientation with respect to the interface is obtained by the above equations (7) and (8).

In the low molecular organic EL element, the direction of the dipole of excitons generated in the light emitting layer is random. In this case, the in-plane wave number dependence of the average dissipated energy is given by the following equation (9).

First, a dipole is placed in the light-emitting layer, and the in-plane wave number dependence of the tsu energy is calculated from the above equation (9). All emission energy, W (k _||) equally to the integral from the in-plane wavenumber k _{|| = 0} to infinity, the corresponding dissipated energy W for each mode (k _||) in the peak region of that mode It is equal to the integral over the in-plane wavenumber range. The ratio of both gives the ratio of the dissipated energy to that mode to the total emitted energy.

  The lattice pitch P (that is, the distance P1 between the centers of the recesses 18b and corresponds to the distance P2 between the centers of the protrusions 12a) is given by a different formula depending on the surface plasmon mode to be extracted.

Specifically, the lattice pitch P ₀ is given by the following equation (10) when a triangular lattice structure is formed as a two-dimensional lattice structure.

Further, the lattice pitch P ₀ is given by the following equation (11) when a square lattice structure is formed as a two-dimensional lattice structure.

  Note that the lattice pitch P given by the equations (10) and (11) is equal to the particle diameter (that is, the particle diameter) D of the particles.

That is, the surface plasmon mode to be extracted is different between the case where the triangular lattice structure is formed as the two-dimensional lattice structure and the case where the tetragonal lattice structure is taken, and the lattice pitch P ₀ satisfying the above-described expression (10). When a triangular lattice structure is produced and when a square lattice structure is produced with a lattice pitch P ₀ satisfying the above-mentioned expression (11), the energy of the surface plasmon can be extracted as light.

However, since any light emitting material has a width in the light emission wavelength in the light emission spectrum, the lattice pitch P corresponds to such a width, and the variation allowable value within the range given by the following equation (1). It shall have

From the equations (10), (11), and (1) thus given, the particle size of the particles for forming the particle single layer film is calculated in the etching method using the particle single layer film. Note that the etching method using such a particle single layer film can be created only when a triangular lattice structure is formed as a two-dimensional lattice structure.

Specifically, the organic light emitting diode 10 is formed from the side of Al (corresponding to the reflective layer 22) formed on the substrate 12 by IZO (corresponding to the anode conductive layer 14) / HAT-CN [film thickness 80 nm]. This corresponds to (hole injection layer 16-1). ) / T400 [film thickness 70 nm] (corresponding to hole transport layer 16-2) / MDP3FL (2,7-Bis {2- [phenyl (m-tolyl) amino] -9,9-dimethyl-fluorene) in ADN -7-yl} -9,9-dimethyl-fluorene) doped at 7% concentration [film thickness 40 nm] (corresponding to light-emitting layer 16-3a) / Alq ₃ (tris (8-hydroxyquinolinato) aluminum) Doped with C545T at a concentration of 1% [film thickness 10 nm] (corresponding to the light-emitting layer 16-3b) / CBP doped with Ir (piq) ₃ at a concentration of 8.5% [film thickness 20 nm] Corresponding to the light emitting layer 16-3c) / E913 [film thickness 50 nm] (corresponding to the electron transporting layer 16-4) / l [film thickness 10 nm] (corresponding to the metal layer 18-1) / IZO [film thickness 110 nm] (corresponding to the transparent conductive layer 18-2). Since it is inferior to an organic light emitting material, when the peak wavelength value λ ₁ of the emission spectrum to be enhanced is 630 nm, energy dissipation as shown in FIG. 4 is shown.

  In the calculation, the thickness of the reflective layer was infinite.

  ADN is 9,10-di (2-naphthyl) anthracene, and C545T is 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H, 11H-10-. (2-benzothiazolyl) quinolizine [9,9a, 1-gh].

CBP is 4,4-N, N′-dicarbazole-biphenyl, T400 is a hole transport material manufactured by Bando Chemicals, and E913 is an electron transport material manufactured by Sun Fine Chemicals.

In the case of the cathode top emission type configuration, three types of surface plasmon modes are obtained: a reflective layer / anode conductive layer, an organic layer / metal layer, and a metal layer / anode conductive layer. Focusing on the organic layer / metal layer having a large energy amount, the lattice pitch P and the particle size for extracting the surface plasmon energy as light were calculated.

  FIG. 4 shows a distance of 60 nm from the back surface 18-1c of the metal layer 18-1 (that is, the bottom surface of the metal layer 18-1 and the back surface 18a of the cathode conductive layer 18), that is, the light emitting layer 16. Energy dissipation when a dipole is placed at the center of -3c (the distance between the upper interface and the lower interface is the same distance in the light emitting layer) is calculated using the above equation (9). The results are shown. In the calculation, the thickness of the reflective layer was infinite.

In Figure 4, the in-plane wavenumber ^{_{k || = 21.6μm -1, k ||}} = 18.1μm -1 and _k || = each peak _Q 1 at the position of 12.8μm _{^-1, Q 2,} Q ₃ is Is recognized. These peaks Q ₁ , Q ₂ and Q ₃ correspond to the surface plasmon mode.

Here, the first mode (peak Q ₁ ) from the larger in-plane wave number, that is, k _|| = 21.6 μm ⁻¹ is the surface 18-1a of the metal layer 18-1 (that is, the metal layer 18). -1 is the surface on which the transparent conductive layer 18-2 is located.) Is a surface plasmon mode in which energy is concentrated, and is the second mode (peak Q ₂ ) from the side with the larger in-plane wavenumber, That is, k _|| = 18.1 μm ⁻¹ is a surface plasmon mode in which energy is concentrated on the surface of the reflective layer 22 (that is, the upper surface of the reflective layer 22 and the side where the transparent conductive layer 14 is located). The third mode (peak Q ₃ ) from the side with the larger in-plane wave number, that is, k _|| = 12.8 μm ⁻¹ is the back surface 18-1c of the metal layer 18-1 (that is, the cathode conductive layer 18). The energy is concentrated on the back surface 18a. It is a surface plasmon mode.

  The method described above was used as the method for identifying the surface plasmon mode from the plurality of guided modes appearing in the energy dissipation diagram shown in FIG.

Here, in FIG. 4, the fourth mode (peak Q ₄ ) from the larger in-plane wave number is a peak related to the TE waveguide mode. The TE waveguide mode has a smaller dissipated energy than the surface plasmon mode.

Here, the third mode (peak Q ₃ ) from the side with the larger in-plane wave number, that is, the surface plasmon mode (k _|| = 12.8 μm ⁻¹ ) concentrated on the back surface 18-1c of the metal layer 18-1. Since the energy is large, the particle size of the particles can be calculated from the above equations (10), (11), and (1) using the wave number (propagation constant) of the surface plasmon.

  Such particles preferably have a coefficient of variation in particle size (that is, a value obtained by dividing the standard deviation by the average value) of 15% or less, more preferably 10% or less, and even more preferably 5% or less.

  When particles having a small particle size variation coefficient and a small particle size variation are used in this way, it is difficult to generate defective portions where particles are not present in the formed particle single layer film, and the particle single layer film has a small misalignment. Can be formed.

  If the deviation of the arrangement of the particle single layer film is small, the deviation of the arrangement in the two-dimensional lattice structure finally formed on the back surface 18a of the cathode conductive layer 18 (the back surface 18-1c of the metal layer 18-1) is also reduced. . And it is preferable that the displacement of the two-dimensional lattice structure is small because surface plasmons are efficiently converted into light in the metal layer 18-1 in the cathode conductive layer 18.

Examples of the particle material constituting the particle single layer film include metals such as Al, Au, Ti, Pt, Ag, Cu, Cr, Fe, Ni, and Si, SiO ₂ , Al ₂ O ₃ , TiO ₂ , and MgO _2. And metal oxides such as CaO ₂ , organic polymers such as polystyrene and polymethyl methacrylate, other semiconductor materials, and inorganic polymers. Any of these may be used alone or in combination of two or more.

Based on the lattice pitch to be acquired, the particle diameter of the particles can be calculated from the above-described equation (10).

  Moreover, when water (or hydrophilic liquid) is used as the lower layer liquid, the particles preferably have a hydrophobic surface. If the surface of the particles is hydrophobic, when the particle dispersion is developed on the liquid surface of the lower layer liquid in the water tank to form the particle single layer film, the particle single layer film can be easily used using water as the lower layer liquid. And the particle monolayer film can be easily transferred onto the substrate 12.

  Of the particle materials shown above, organic polymer particle materials such as polystyrene can be used as they are because the surface is hydrophobic, but metal and metal oxide particle materials can be made hydrophobic. It can be used by making it hydrophobic with an agent. Examples of such hydrophobizing agents include surfactants and alkoxysilanes.

  The method of using a surfactant as a hydrophobizing agent is effective for hydrophobizing a wide range of materials and is suitable for particulate materials such as metals and metal oxides.

  As such surfactants, cationic surfactants such as hexadecyltrimethylammonium bromide and decyltrimethylammonium bromide, and anionic surfactants such as sodium dodecyl sulfate and sodium 4-octylbenzenesulfonate can be used. . Furthermore, alkanethiol, disulfide compound, tetradecanoic acid, octadecanoic acid, and the like can also be used.

  Such a hydrophobizing treatment using a surfactant may be performed in a liquid by dispersing particles in a liquid such as an organic solvent or water, or may be performed on particles in a dry state.

  When the hydrophobization treatment is performed in the liquid, for example, volatile substances composed of at least one of chloroform, methanol, ethanol, isopropanol, methyl ethyl ketone, ethyl ethyl ketone, toluene, n-hexane, cyclohexane, ethyl acetate, butyl acetate and the like. What is necessary is just to add and disperse | distribute the particle | grains of hydrophobization object in an organic solvent, and after that, surfactant may be mixed and dispersion | distributed. When the surfactant is added after the particles are dispersed in this manner, the surface of the particles can be more uniformly hydrophobized.

  The dispersion liquid after such a hydrophobization treatment can be used as a dispersion liquid for dropping on the liquid surface of the lower layer water as it is.

  If the particles to be hydrophobized are in the form of an aqueous dispersion, a surfactant is added to the aqueous dispersion, the surface of the particles is hydrophobized with an aqueous phase, and then an organic solvent is added to make the hydrophobized treatment. An oil phase extraction method is also effective. The dispersion thus obtained (that is, a dispersion in which particles are dispersed in an organic solvent) can be used as a dispersion for dripping the liquid on the surface of the lower layer water as it is.

  In order to improve the particle dispersibility of this dispersion, the type of organic solvent and the type of surfactant are appropriately selected and combined. By using a dispersion having a high particle dispersibility, it is possible to suppress the aggregation of particles, and it is easy to obtain a particle monolayer film in which each particle is two-dimensionally closely packed with high accuracy.

  For example, when chloroform is selected as the organic solvent, it is preferable to use decyltrimethylammonium bromide as the surfactant. Examples of the combination of the organic solvent and the surfactant for enhancing the particle dispersibility of the dispersion include ethanol and sodium dodecyl sulfate, methanol and sodium 4-octyl benzene sulfonate, methyl ethyl ketone and octadecanoic acid, and the like.

  The ratio of the particles to be hydrophobized and the surfactant is preferably such that the mass of the surfactant is 1 to 20% with respect to the mass of the particles to be hydrophobized.

  In addition, in such a hydrophobizing treatment, it is effective in terms of improving particle dispersibility to stir the dispersion during the treatment or to irradiate the dispersion with ultrasonic waves.

The method of using alkoxysilane as a hydrophobizing agent is effective when hydrophobizing particulate materials such as Si, Fe, and Al and particulate materials such as SiO ₂ , Al ₂ O ₃ , and TiO ₂ . It should be noted that the present invention is not limited to these particle materials, and can be basically applied to any particle material as long as it has a hydroxyl group or the like on its surface.

  Alkoxysilanes include monomethyltrimethoxysilane, monomethyltriethoxysilane, dimethyldiethoxysilane phenyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxy cyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypro Rutriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, N-phenyl-3aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane , 3-isocyanatopropyltriethoxysilane and the like.

  When alkoxysilane is used as a hydrophobizing agent, it is hydrolyzed by hydrolysis to an alkoxysilyl group silanol group in the alkoxysilane, and this silanol group is dehydrated and condensed to a hydroxyl group on the particle surface. Therefore, it is desirable to perform hydrophobization using alkoxysilane in water.

  Thus, when hydrophobizing in water, for example, it is preferable to use a dispersing agent such as a surfactant to stabilize the dispersion state of the particles before hydrophobizing. In addition, since the hydrophobizing effect of alkoxysilane may be reduced depending on the type of the dispersant, the combination of the dispersant and the alkoxysilane is appropriately selected.

  As a specific method for hydrophobizing with alkoxysilane, first, particles are dispersed in water, and this is mixed with an alkoxysilane-containing aqueous solution (that is, an aqueous solution containing an alkoxysilane hydrolyzate). The reaction is performed for a predetermined time, preferably 0.5 to 12 hours, with appropriate stirring in the range of room temperature to 40 ° C.

  By carrying out the reaction under such conditions, it is possible to obtain a dispersion of particles that are appropriately hydrophobized and sufficiently hydrophobized. At this time, if the reaction proceeds excessively, the silanol groups react with each other and the particles are bonded to each other, the particle dispersibility of the dispersion is lowered, and the resulting particle monolayer film is partially clustered. It is easy to become two or more layers aggregated together. On the other hand, when the reaction is insufficient, the surface of the particles is not sufficiently hydrophobized, and the obtained particle monolayer film tends to have a wide pitch between the particles.

  In addition, since alkoxysilanes other than amines are hydrolyzed under acidic or alkaline conditions, it is necessary to adjust the pH of the dispersion to acidic or alkaline during the reaction. The method for adjusting the pH is not limited, but a method of adding an aqueous acetic acid solution having a concentration of 0.1 to 2.0% by mass is preferable because an effect of stabilizing a silanol group can be obtained in addition to promoting hydrolysis. .

  The ratio of the particles to be hydrophobized and the alkoxysilane is preferably in the range where the mass of the alkoxysilane is 1 to 20 times the mass of the particles to be hydrophobized.

  After the reaction for a predetermined time, one or more kinds of the volatile organic solvents described above are added to this dispersion, and the oil-hydrophobized particles in water are extracted. At this time, the volume of the organic solvent to be added is preferably in the range of 0.3 to 3 times the dispersion before addition of the organic solvent.

  The dispersion obtained by oil phase extraction (that is, a dispersion in which particles are dispersed in an organic solvent) can be used as a dispersion for dropping it on the surface of the lower layer water as it is.

In such a hydrophobization treatment, it is preferable to carry out stirring, ultrasonic irradiation, etc. in order to increase the particle dispersibility of the dispersion during the treatment. By increasing the particle dispersibility of the dispersion, the particles are clustered. The particle monolayer film in which each particle is two-dimensionally closely packed with high accuracy can be easily obtained.

  The concentration of the particles of the dispersion is preferably 1 to 10% by mass, and the dropping rate of the dispersion into the lower layer water is preferably 0.001 to 0.01 ml / second.

  When the concentration and the amount of the drops in the dispersion are in the above ranges, the particles partially aggregate to form two or more layers, a defect portion where no particles are present, a pitch between particles is widened, etc. Thus, it is easy to obtain a particle monolayer film in which each particle is two-dimensionally closely packed with high accuracy.

  The particle monolayer film forming step is preferably performed under ultrasonic irradiation conditions. When the particle monolayer film forming step is performed while irradiating ultrasonic waves from the lower layer water toward the liquid surface, the aggregation state of the particles is reduced. And the effect of promoting close packing of particles are obtained, and a particle monolayer film in which each particle is close packed in two dimensions with high accuracy can be obtained.

  At this time, the output of ultrasonic waves is preferably 1 to 1200 W, and more preferably 50 to 600 W. Moreover, although there is no restriction | limiting in particular in the frequency of an ultrasonic wave, For example, 28kHz-5MHz is preferable and 700kHz-2MHz is more preferable.

  In general, if the frequency (referred to here as the frequency of ultrasonic waves) is too high, the energy absorption of water molecules begins and a phenomenon in which water vapor or water droplets rise from the water surface is not preferable. In general, when the frequency is too low, the cavitation radius in the lower layer water is increased, bubbles are generated in the water, and rise toward the water surface. When such bubbles are accumulated under the particle monolayer film formed on the liquid surface of the lower layer water, the flatness of the water surface is lost, and an appropriate particle monolayer film cannot be formed.

  In addition, standing waves are generated on the water surface by ultrasonic irradiation. If the output is too high at any frequency, or if the wave height of the water surface becomes too high due to the tuning conditions of the ultrasonic vibrator and oscillator, the particle monolayer film may be destroyed by the water surface wave.

  For this reason, when the frequency of the ultrasonic wave is appropriately set, the particle monolayer can be effectively promoted without destroying the particle monolayer film being formed. However, when the particle diameter is small, for example, 100 nm or less, the natural frequency of the particle becomes very high, and it is difficult to apply ultrasonic vibration as calculated.

  In this case, the calculation is performed assuming that the natural vibration is given to the mass of the particle dimer, trimer,..., About 20 mer, and the necessary frequency is reduced to a realistic range. be able to. Even when ultrasonic vibration corresponding to the natural frequency of the aggregate of particles is given, the monolayering of the particles is promoted.

  The ultrasonic irradiation time may be sufficient for promoting the monolayer formation of the particles, and the required time varies depending on the particle size, the frequency of the ultrasonic waves, the temperature of the lower layer water, and the like.

  However, under normal production conditions, it is preferably performed for 10 seconds to 60 minutes, more preferably 3 minutes to 30 minutes.

  In addition to close packing of particles (that is, hexagonal close packing of random arrays), the advantage obtained by ultrasonic irradiation is to break down the soft agglomerates of particles that tend to occur during particle dispersion adjustment. An effect, a point defect once generated, a line defect, or a crystal transition has a certain repair effect.

  The formation of the particle monolayer film on the water surface described above is due to the self-organization of the particles, and the principle is that the particles are floating on the water surface and are in a state in which the particles gather from each other at random movement As a result, the surface tension acts due to the dispersion medium existing between the particles, and as a result, the particles do not exist in a disjointed state, but automatically a two-dimensional close packed structure on the water surface. It is to form. In other words, the formation of the close-packed structure by such surface tension can be said to be mutual adsorption of particles by the capillary force in the lateral direction.

  In particular, for example, when three particles having a spherical shape, such as colloidal silica, with a highly uniform particle size float on the water surface and come into contact with each other, the surface tension is minimized so as to minimize the total length of the water line of the particle group. The three particles are stabilized in an arrangement based on equilateral triangles.

  If the water line is at the apex of the particle group, that is, if the particles are submerged below the liquid surface, such self-organization does not occur and a particle monolayer film is not formed. Therefore, when one of the particles and the lower layer water is hydrophobic, it is important to make the other hydrophilic so that the particles do not dive under the water surface.

As the lower layer liquid, it is preferable to use water as described above. When water is used, relatively large surface free energy acts, and the close-packed arrangement of particles once generated is stable on the liquid surface. It will be easier to sustain.

(1-2) Transfer Step In the transfer step, the particle single layer film formed on the liquid surface of the lower layer water by the particle single layer film formation step is transferred onto the substrate original plate, which is the object to be etched, in the single layer state. .

  The specific method for transferring the particle monolayer film onto the substrate original plate is not particularly limited. For example, while maintaining the hydrophobic substrate original plate substantially parallel to the particle monolayer film from above, The particle monolayer film is brought into contact with the particle monolayer film, and the particle monolayer film is transferred to the substrate original plate by the affinity between the particle monolayer film and the substrate original plate, both of which are hydrophobic, and transferred to the substrate original plate. The method can be used.

  More specifically, before forming the particle monolayer film, the substrate original plate is arranged in a substantially horizontal direction in the lower layer water of the water tank in advance, and after the particle monolayer film is formed on the liquid surface of the lower layer water By gradually lowering the liquid level, the particle monolayer film is transferred onto the substrate original plate.

  According to such a method, the particle monolayer film can be transferred onto the substrate original plate without using a special apparatus. However, even if the particle monolayer film has a larger area, its two-dimensional closest packing The so-called LB trough method is preferably employed in that it can be easily transferred onto the substrate original plate while maintaining the filled state.

  In the LB trough method, the substrate original plate is immersed in a substantially vertical direction with respect to the liquid surface of the lower layer water in the lower layer water in the water tank, and the above-described particle single layer film forming step is performed in that state. A particle monolayer film is formed on the surface.

  And after a particle | grain single layer film formation process, the particle | grain single layer film | membrane formed on the liquid level of lower layer water can be moved on a board | substrate original plate by pulling up a substrate original plate upwards.

  At this time, since the particle single layer film is already formed in a single layer state on the liquid surface of the lower layer water by the particle single layer film forming step, the temperature condition of the transition step (that is, the temperature of the lower layer water). ) And the pulling speed of the substrate original plate to some extent, there is no fear that the particle monolayer film will collapse and become multi-layered.

  The temperature of the lower layer water, which is the temperature condition of the transition process, is usually about 10 to 30 ° C., depending on the environmental temperature that varies depending on the season and weather.

  In addition, as a water tank at this time, a surface pressure sensor based on the principle of a Wilhelmy plate that measures the surface pressure of the particle monolayer film, and a movable barrier that compresses the particle monolayer film in the direction along the liquid surface of the lower layer water. When the LB trough apparatus comprising the above is used, a larger-area particle monolayer film can be more stably transferred onto the substrate original plate.

  According to such an apparatus, the particle monolayer film can be compressed to a preferable diffusion pressure (density) while measuring the surface pressure of the particle monolayer film, and moved toward the substrate original plate at a constant speed. Can be made. For this reason, the transition from the liquid surface of the lower layer water of the particle single layer film to the substrate original plate smoothly proceeds, and problems such as the fact that only the particle single layer film can move on the substrate original plate in a small area are less likely to occur.

A preferable diffusion pressure is 5 to 80 mNm ⁻¹ , more preferably 10 to 40 mNm ⁻¹ . With such a diffusion pressure, it is easy to obtain a particle monolayer film in which each particle is denser and densely packed two-dimensionally. Moreover, as a speed | rate which pulls up a board | substrate original plate, 0.5-20 mm / min is preferable.

  After such a transition process, after the substrate original plate surface is coated with the particle single layer film, a fixing process for fixing the particle single layer film on the substrate original plate may be performed as necessary.

  By fixing the particle monolayer film on the substrate original plate by the fixing process, the possibility of particles moving on the substrate original plate during the subsequent dry etching is suppressed, and the surface of the substrate original plate can be more stably and highly accurately detected. It becomes possible to etch. As the dry etching progresses, the particle size of each particle gradually decreases, so that the possibility of moving on the substrate original plate increases.

  As such a fixing treatment method, there are a method using a binder and a sintering method. In the method using a binder, a binder solution is supplied to the particle single layer film side of the substrate original plate on which the particle single layer film is formed, and this is infiltrated between the particle single layer film and the substrate original plate.

  The amount of the binder used is preferably 0.001 to 0.002 times the mass of the particle monolayer film. In such a range, there is too much binder and the binder is clogged between the particles, and there is no problem of adversely affecting the accuracy of the particle monolayer film, and the particles can be sufficiently fixed. It is.

  When a large amount of the binder solution has been supplied, after the binder solution has permeated, the excess of the binder solution may be removed by using a spin coater or tilting the substrate.

  As the type of the binder, it is possible to use alkoxysilane, a general organic binder, an inorganic binder or the like previously shown as a hydrophobizing agent. After the binder solution has penetrated, heat treatment is appropriately performed according to the type of binder. To do. For example, when using alkoxysilane as a binder, it is preferable to heat-process at 40-80 degreeC for 3 to 60 minutes.

  Further, when a sintering method is used as the fixing treatment method, the substrate original plate on which the particle monolayer film is formed is heated to fuse each particle constituting the particle monolayer film to the substrate. . The heating temperature may be determined according to the material of the particle and the material of the substrate, but particles having a particle size of 1 μm or less start an interfacial reaction at a temperature lower than the original melting point of the substance, so that the relatively low temperature side The sintering is complete.

  If the heating temperature is too high at the time of sintering, the fused area of the particles increases, and as a result, the shape of the particle monolayer film may change, which may adversely affect accuracy.

Moreover, since it may oxidize a board | substrate and each particle | grain when heating is performed in air, it is preferable to carry out in inert gas atmosphere. When sintering is performed in an atmosphere containing oxygen, it is necessary to set conditions in consideration of an oxide layer in a dry etching process described later.

In the particle single layer film thus formed on the substrate original plate, the deviation S (%) of the particle arrangement defined by the following formula (12) is preferably 10% or less.
A: Average particle diameter of particles B: Average pitch between particles in a particle monolayer film

  In this equation (12), the “average particle diameter” of “A” is the average primary particle diameter of the particles constituting the particle monolayer film, and the particle size distribution calculated by the particle dynamic light scattering method. Can be obtained by a conventional method from a peak obtained by fitting to a Gaussian curve.

  The “average pitch between particles in the particle monolayer film” of “B” is the average value of the distances between the vertices of two adjacent particles in the particle monolayer film. If the particles are spherical, the distance between the vertices of adjacent particles is equal to the distance between the centers of the adjacent particles.

  The average pitch between particles in the particle single layer film is obtained in the same manner as the center-to-center distance P2 of the convex portions 12a by AFM.

In the particle monolayer film in which the deviation S of the particle arrangement is 10% or less, each particle is two-dimensionally closely packed, the interval between the particles is controlled, and the arrangement accuracy is high.

(2) Dry etching process The substrate surface covered with the particle single layer film as described above is dry-etched to obtain a substrate 12 having a structure in which a plurality of convex portions 12b are periodically arranged in two dimensions. can do.

  Specifically, when dry etching is started, first, the etching gas passes through the gaps between the particles constituting the particle monolayer film and reaches the surface of the substrate original plate, and the etching gas reaches the surface where the etching gas reaches. As a result, the substrate surface is etched to form concave portions, and convex portions appear at portions where the respective particles are located.

  Thereafter, when dry etching is further continued, the particles on each convex portion are gradually etched by the etching gas and become smaller, and the concave portion on the surface of the substrate original plate becomes deeper.

  Finally, each particle is removed after functioning as a mask, and a structure in which a plurality of convex portions are periodically arranged two-dimensionally is formed on the surface of the original substrate. In this way, a plurality of convex portions 12 b are formed on the surface 12 a of the substrate 12, and a two-dimensional lattice structure is formed on the substrate 12 by the plurality of convex portions 12.

  Further, by adjusting the dry etching conditions (bias, gas flow rate, deposition gas type and amount, etc.), the height and shape of the convex portions to be formed can be adjusted.

Examples of the etching gas used for dry etching include Ar, SF ₆ , F ₂ , CF ₄ , C ₄ F ₈ , C ₅ F ₈ , C ₂ F ₆ , C ₃ F ₆ , C ₄ F ₆ , and CHF _3. , CH ₂ F ₂ , CH ₃ F, C ₃ F ₈ , Cl ₂ , CCl ₄ , SiCl ₄ , BCl ₂ , BCl ₃ , BC ₂ , Br ₂ , Br ₃ , HBr, CBrF ₃ , HCl, CH ₄ , NH ₃ , O ₂ , H ₂ , N ₂ , CO, CO _{2 and the} like, but are not limited thereto as long as the effects of the present invention are not impaired. One or more of these can be used depending on the particles constituting the particle monolayer film, the material of the substrate, and the like.

  As an etching apparatus that can be used, a reactive ion etching apparatus, an ion beam etching apparatus, or the like that can perform anisotropic etching and can generate a bias electric field of about 10 W at the minimum can generate plasma. There are no particular restrictions on the specifications such as system, electrode structure, chamber structure, and frequency of the high frequency power supply.

  Various conditions (particle single layer) are set so that the etching selectivity in this dry etching step (that is, the etching rate of the substrate / the etching rate of the particle single layer film) is 1.0 or less of the structural design of the fine structure. It is preferable to set the particle material constituting the film, the substrate material, the type of etching gas, the bias power, the antenna power, the gas flow rate and pressure, the etching time, and the like.

For example, when colloidal silica particles are selected as the particles constituting the particle monolayer film as an etching mask, a quartz substrate is selected as the substrate, and a particle monolayer film made of colloidal silica particles is formed on the quartz substrate. By using a gas such as Ar or CF ₄ as the gas, etching with a relatively low pitch to amplitude ratio can be performed.

  Further, when the electric field bias is set to several tens to several thousand W (depending on the electrode area of the dry etching apparatus), positive charge particles in the etching gas in a plasma state are accelerated and incident on the substrate at a high speed almost vertically. Therefore, when a gas having reactivity with the substrate is used, the reaction rate of the physicochemical etching in the vertical direction can be increased.

  Depending on the combination of the material of the substrate and the type of etching gas, in dry etching, isotropic etching due to radicals generated by plasma also occurs in parallel. Etching with radicals is chemical etching, and isotropically etches in any direction of the object to be etched.

  Further, since radicals have no charge, the etching rate cannot be controlled by setting the bias power, and the etching rate is controlled by the concentration of the etching gas in the chamber. In order to perform anisotropic etching with charged particles, a certain level of gas pressure must be maintained. Therefore, as long as a reactive gas is used, the effect of isotropic etching cannot be reduced to zero. However, the method of slowing the reaction rate of radicals by cooling the substrate is widely used, and since there are many devices equipped with such a mechanism, it is preferable to use it.

  Furthermore, in the dry etching process, the bias power and pressure are mainly adjusted, and depending on the situation, so-called deposition gas is used in combination, so that the distance between the centers of the protrusions on the substrate surface and the height of the protrusions can be reduced. A two-dimensional lattice structure having a relatively low ratio (distance between centers / height) can be formed.

For the structure formed on the surface of the substrate in this manner, when the distance C between the centers of the convex portions is obtained in the same manner as the method for obtaining the average pitch B between the particles in the particle monolayer film, It becomes almost the same value as the average pitch B of the used particle monolayer film. Further, regarding this structure, when an alignment shift S ′ (%) defined by the following equation (13) is obtained, the value is also almost the same as the alignment shift S in the used particle monolayer film.
A: Average particle diameter of particles constituting the used particle monolayer film C: Distance between centers of convex portions formed on the substrate surface

  Note that the substrate 12 formed as described above and having a structure in which a plurality of convex portions are periodically two-dimensionally arranged on the surface is used as a mold, and the structure of the surface of the mold is transferred to the substrate original substrate 12. May be produced.

  The structure of the mold surface can be transferred by a known method such as the nanoimprint method, the hot press method, the injection molding method, or the UV embossing method disclosed in Patent Document 7 described above.

As the number of times of transfer increases, the shape of the fine irregularities becomes dull, so the practical number of times of transfer from the original master is preferably within 5 times.

  As described above, the reflective layer 22 and the anode conductive layer 14 are sequentially laminated on the surface 12a of the substrate 12 on which the two-dimensional lattice structure is formed by the plurality of convex portions 12b, and holes are formed on the surface 14a of the anode conductive layer 14. An injection layer 16-1, a hole transport layer 16-2, a light emitting layer 16-3 (light emitting layers 16-3a, 16-3b, 16-3c), an electron transport layer 16-4, and an electron injection layer 16-5 are sequentially stacked. The organic EL layer 16 is formed, and the cathode conductive layer 18 is formed by sequentially laminating the metal layer 18-1 and the transparent conductive layer 18-2 on the surface 16-5a of the electron injection layer 16-5. The organic light emitting diode 10 can be obtained.

  The method for laminating these layers is not particularly limited, and a known technique used for manufacturing a general organic light emitting diode can be used.

  For example, the anode conductive layer 14 and the transparent conductive layer 18-2 can be formed by a sputtering method, a vacuum deposition method, or the like, respectively. Further, the reflective layer 22, the hole injection layer 16-1, the hole transport layer 16-2, the light emitting layer 16-3 (light emitting layers 16-3a, 16-3b, 16-3c), the electron transport layer 16-4, the electron injection Each of the layer 16-5 and the metal layer 18-1 can be formed by a vacuum deposition method.

Since the thickness of each of these layers is very thin, the two-dimensional lattice structure by the plurality of convex portions 12b on the surface 12a of the substrate 12 is reflected to the transparent conductive layer 18-2 by sequentially laminating each layer as described above. In the reflective layer 22 and the metal layer 18-1, a two-dimensional lattice structure including a plurality of convex portions or concave portions corresponding to the two-dimensional lattice structure including the plurality of convex portions 12b formed on the surface 12a of the substrate 12 is formed. It becomes.

  Next, a case where the organic light emitting diode 10 is manufactured based on the above-described manufacturing method will be described with a specific example.

As the organic light emitting diode 10 to be manufactured, substrate / Al [film thickness 100 nm] / IZO [film thickness 20 nm] / HAT-CN [film thickness 80 nm] / T400 [film thickness 70 nm], / MDP3FL @ ADN (7%) [ Film thickness 40 nm] / C545T @ Alq ₃ (1%) [film thickness 10 nm] / Ir (piq) ₃ @CBP (8.5%) [film thickness 20 nm] / E913 [film thickness 50 nm] / Al [film thickness 10 nm ] / IZO [film thickness 110 nm].

Since the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials, the peak wavelength value λ ₁ of the emission spectrum to be enhanced is set to 630 nm.

That is, the organic light emitting diode 10 includes a substrate 12 made of quartz glass, a reflective layer 22 made of Al having a thickness of 100 nm, a 20 nm thick anode conductive layer 14 made of IZO, and a HAT-CN. 80 nm thick hole injection layer 16-1 formed by T400, 70 nm thick hole transport layer 16-2 formed by T400, and 40 nm thick light emitting layer formed by ADN doped with 7% MDP3FL Light emitting layer 16-3b formed of 16-3a, Alq ₃ doped with 1% C545T and 10 nm thick, and light emitting 20 nm thick formed of Ir (piq) ₃ doped with 8.5% CBP Layer 16-3c, electron transport layer 16-4 having a thickness of 50 nm formed by E913, and metal layer having a thickness of 10 nm formed by Al. And 8-1, is formed by a transparent conductive layer 18-2 having a thickness of 110nm formed by IZO.

  In order to fabricate the organic light emitting diode 10, first, the particle size of the particles that form the particle monolayer film necessary for fabricating the two-dimensional lattice structure on the surface 12a of the substrate 12 by the plurality of convex portions 12b is calculated. To do.

  That is, in the organic light emitting diode 10, the intensity of energy dissipation when the thickness of the metal layer 18-1 in the cathode conductive layer 18 is 10 nm is expressed by the above equations (7), (8), and (9). Ask.

  In the calculation, the thickness of the reflective layer was infinite.

  Here, the particle monolayer film when the energy of surface plasmons generated on the back surface 18-1c of the metal layer 18-1 where the dissipated energy is most concentrated (that is, the back surface 18a of the cathode conductive layer 18) is extracted as propagating light. The particle diameter of the particles forming the sapphire is calculated.

In the above equations (7), (8), and (9), the third mode (peak) from the larger wave number is the energy dissipation of the surface plasmon generated on the back surface 18-1c of the metal layer 18-1. Therefore, the in-plane wave number k _|| As described above, the in-plane wave number of this mode is k _|| = 12.8 μm ⁻¹ .

  In addition, as a formula for obtaining the reflection coefficient of the ordinary multilayer thin film included in the above formulas (7) and (8), non-patent literature ("Plasmonics-Fundamentals and Applications" by Takayuki Okamoto and Kotaro Kajikawa, Kodansha Scientific Fig. (Published October 1, 2010), P16-22).

In FIG. 4, k _|| of the _third mode (that is, peak Q ₃ ) from the side with the larger in-plane wavenumber is 12.8 μm ⁻¹ . That is, the in-plane wave number k _|| that gives the energy dissipation peak to the surface plasmon is 12.8 μm ⁻¹ .

  When this value is substituted into the above equation (10), the particle diameter D of a particle for producing a fine structure corresponding to this wave number (that is, a two-dimensional lattice structure) is calculated as 567 nm. It was done.

In this specific example, the particle size of the particles forming the particle monolayer film is calculated using the above equation (10) in order to explain the etching method using the particle monolayer film. When the organic light emitting diode 10 is produced by a method other than the etching method using a single layer film, the lattice pitch P is calculated using the above-described equations (10) and (11) (note that the lattice pitch P is The value is within the range shown in the formula (1).), And it may be produced by adjusting various conditions so that the calculated lattice pitch P is obtained.

  Based on the value of the particle diameter D of the particle calculated by the above equation (10), 5.0 mass% water of colloidal silica having an average particle diameter of 562.3 nm and a coefficient of variation of the particle diameter of 4.0%. A dispersion (dispersion) was prepared. The average particle diameter and the coefficient of variation of the particle were calculated from a peak obtained by fitting a particle size distribution obtained by a particle dynamic light scattering method using Zetasizer Nano-ZS manufactured by Malvern Instruments Ltd. to a Gaussian curve.

  Next, in order to hydrophobize the surface of the colloidal silica in the prepared dispersion, an aqueous solution containing a hydrolyzate of phenyltriethoxysilane having a concentration of 1.0% by mass is added to the dispersion, and about 40 °. The reaction was performed for 3 hours. At this time, the dispersion and the aqueous solution were mixed so that the mass of phenyltriethoxysilane was 0.015 times the mass of the colloidal silica particles.

Then, methyl isobutyl ketone having a volume five times that of the dispersion was added to the dispersion after the reaction and stirred to extract the hydrophobized colloidal silica in the oil phase.

  A hydrophobized colloidal silica dispersion liquid having a concentration of 1.05% by mass obtained in this manner includes a surface pressure sensor for measuring the surface pressure of the particle monolayer film, and a movable barrier for compressing the particle monolayer film in a direction along the liquid surface. It dropped at a drop rate of 0.01 ml / second onto the liquid surface (water was used as the lower layer liquid and the water temperature was 26.5 ° C.) stored in the water tank (LB trough device) provided. In the lower layer water stored in the water tank, a transparent quartz substrate (30 mm × 30 mm × 1.0 mm, double-sided mirror polished) to be used as the substrate 12 of the organic light emitting diode 10 in advance is immersed in a substantially vertical direction. ing.

  From the time when the hydrophobized colloidal silica dispersion liquid started dripping onto the surface of the lower layer water, it was made hydrophobic by irradiating with ultrasonic waves for 10 minutes from the lower layer water toward the liquid surface under the conditions of an output of 100 W and a frequency of 1500 kHz. The colloidal silica particles were promoted to be two-dimensionally closely packed, and methyl isobutyl ketone, which is the organic solvent in the dispersion, was volatilized to form a particle monolayer film on the liquid surface of the lower layer water.

Thereafter, the formed particle monolayer film is compressed by a movable barrier until the diffusion pressure becomes 22 to 30 mNm ⁻¹ , the substrate 12 is pulled up at a speed of 3 mm / min, and the particle monolayer film is formed on one surface of the substrate 12. Removed. One surface of the substrate 12 is a surface on which a two-dimensional lattice structure is to be formed.

  Next, as a process of fixing the particle monolayer film transferred onto one surface of the substrate 12 to the one surface, 0.15 as a binder on one surface of the substrate 12 from which the particle monolayer film has been transferred. A hydrolyzate of mass% monomethyltrimethoxysilane was infiltrated, and then the excess of the hydrolyzate was removed by treatment with a spin coater (3000 rpm) for 1 minute. And the board | substrate 12 which removed the excess part of the hydrolyzed liquid was heated at 100 degreeC for 10 minute (s), the binder was made to react, and the board | substrate 12 with which the particle | grain single layer film which consists of colloidal silica particles was formed was acquired.

When the substrate 12 on which the particle monolayer film was formed was obtained in this way, next, the substrate 12 was dry-etched with CHF ₃ gas.

The conditions for this dry etching process were an antenna power of 1500 W, a bias power of 50 to 300 W (13.56 MHz), and a gas flow rate of 50 to 200 sccm.

  When one surface of the substrate 12 after the dry etching process was observed with an AFM, the cross-sectional shape was a truncated cone shape (see FIG. 6B), and the projections were triangular lattices in the planar arrangement. A fine structure arranged in a row was formed (see FIG. 6A).

  Thus, when the center-to-center distance p ′ (lattice constant) of the convex portion in the fine structure formed on one surface of the substrate 12 was measured by AFM, the average value of three tests was 573.7 nm. there were.

  Further, the average value of the convex portions of the fine structure in the 25 μm × 5 μm regions randomly selected from the AFM image was calculated, and the average value of each of the 25 locations was further averaged. The average height h of the convex portions in the fine structure was 62.4 nm.

  Furthermore, as a result of calculation using the above equation (13), the displacement S of the sequence was 2.0%.

Furthermore, the ratio of the average height h to the average value of the center distance p ′ (average height h / center distance p ′) was 0.109.

  Thereafter, Al is deposited as a reflective layer 22 with a thickness of 100 nm on one surface of the substrate 12 on which the microstructure is formed, and IZO is deposited as a positive electrode conductive layer 14 on the reflective layer 22 with a thickness of 20 nm. Then, a HAT-CN film having a thickness of 80 nm was formed as a hole injection layer 16-1 by a vapor deposition method.

Next, T400 is formed as a hole transport layer 16-2 on the hole injection layer 16-1 by a vapor deposition method with a thickness of 70 nm, and then ADN doped with 7% MDP3FL on the hole transport layer 16-2. The formed light emitting layer 16-3a having a thickness of 40 nm, the light emitting layer 16-3b having a thickness of 10 nm formed by Alq ₃ doped with 1% C545T, and Ir (piq) ₃ doped with 8.5% CBP. The light emitting layer 16-3c having a thickness of 20 nm formed by the above method was formed by vapor deposition.

  Further, E913 was deposited as an electron transport layer 16-4 on the light emitting layer 16-3c by a vapor deposition method with a thickness of 50 nm, and further, Al was formed on the electron transport layer 16-4 as a metal layer 18-1. The organic light emitting diode 10 is formed by depositing IZO with a thickness of 110 nm on the metal layer 18-1 as a transparent conductive layer 18-2 on the metal layer 18-1. Produced.

In addition, the light emission area was produced in 2 * 2 mm by using a mask in the case of vapor deposition and sputtering.

  Next, a second embodiment of the organic light emitting diode according to the present invention will be described. The second embodiment is an organic light-emitting diode called a cathode top emission type similar to the first embodiment shown in FIG.

Since the organic light emitting diode 70 has the same configuration as that of the organic light emitting diode 10 according to the first embodiment, detailed description thereof will be omitted.

  Below, the case where the organic light emitting diode 70 is produced will be described with specific examples.

As the organic light emitting diode 70 to be manufactured, substrate / Al [film thickness 100 nm] / IZO [film thickness 20 nm] / HAT-CN [film thickness 40 nm] / T400 [film thickness 50 nm] / MDP3FL @ ADN (7%) [film] Thickness 20 nm] / C545T @ Alq ₃ (1%) [film thickness 2 nm] / Ir (piq) ₃ @CBP (8.5%) [film thickness 10 nm] / E913 [film thickness 30 nm] / Al [film thickness 10 nm] / IZO [film thickness 110 nm].

Since the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials, the peak wavelength value λ ₁ of the emission spectrum to be enhanced is set to 470 nm.

That is, the organic light emitting diode 70 includes a substrate 12 made of quartz glass, a reflective layer 22 made of Al with a thickness of 100 nm, an anode conductive layer 14 made of IZO with a thickness of 20 nm, a HAT- 40 nm thick hole injection layer 16-1 formed by CN, 50 nm thick hole transport layer 16-2 formed by T400, and 20 nm thick light emission formed by ADN doped with 7% MDP3FL A 10 nm thick layer 16-3a, a 2 nm thick light emitting layer 16-3b made of Alq ₃ doped with 1% C545T, and Ir (piq) ₃ made 8.5% doped with CBP Light emitting layer 16-3c, 30 nm thick electron transport layer 16-4 formed of E913, and 10 nm thick metal layer formed of Al And 8-1, is formed by a transparent conductive layer 18-2 having a thickness of 110nm formed by IZO.

  In order to manufacture the organic light emitting diode 70, first, calculation of the particle size of the particles forming a particle single layer film necessary for forming a two-dimensional lattice structure on the surface 12a of the substrate 12 by a plurality of convex portions 12b. Went.

  In this calculation, the position of the dipole is 52 nm from the back surface 18-1c of the metal layer 18-1, that is, the center of the light emitting layer 16-3a (from the upper interface to the lower interface in the light emitting layer). The distance is equidistant.).

  In the calculation, the thickness of the reflective layer was infinite.

  Here, FIG. 5 shows a distance of 52 nm from the back surface 18-1c of the metal layer 18-1 (that is, the bottom surface of the metal layer 18-1 and the back surface 18a of the cathode conductive layer 18). It shows energy dissipation when a dipole is placed at the center of the light emitting layer 16-3a (the distance between the upper interface and the lower interface is the same in the light emitting layer).

In FIG. 5, when a dipole is placed on the substrate side, in-plane wavenumbers k _|| = 35.3 μm ⁻¹ , k _|| = 27.1 μm ⁻¹ and k _|| = 23.7 μm ⁻¹ . Peaks Q ₁ , Q ₂ , and Q ₃ corresponding to the surface plasmon mode are recognized.

The first mode (peak Q ₁ ) from the larger in-plane wave number, that is, k _|| = 35.3 μm ⁻¹ is the surface 18-1a of the metal layer 18-1 (that is, the metal layer 18-1). This is a surface plasmon mode in which energy is concentrated on the upper surface and the side where the transparent conductive layer 18-2 is located.) The second mode (peak Q ₂ ) from the one with the larger in-plane wavenumber, that is, k _|| = 27.1 μm ⁻¹ is a surface plasmon mode in which energy is concentrated on the surface of the reflective layer 22 (that is, the upper surface of the reflective layer 22 and the side where the transparent conductive layer 14 is located). The third mode (peak Q ₃ ) from the higher inner wave number, that is, k _|| = 23.7 μm ⁻¹ is the back surface 18-1c of the metal layer 18-1 (that is, the back surface 18a of the cathode conductive layer 18). A surface plastic where energy is concentrated on It is a common mode.

  The method described above was used as the method for identifying the surface plasmon mode from the plurality of guided modes appearing in the energy dissipation diagram shown in FIG.

Here, in FIG. 5, the fourth mode (peak Q ₄ ) and the fifth mode (peak Q ₅ ) from the larger in-plane wave number are TE waveguide modes, and the sixth mode (peak Q ₆ ) is a peak related to the TM waveguide mode. These TE waveguide mode and TM waveguide mode have lower dissipative energy than the surface plasmon mode.

Here, the third mode (peak Q ₃ ) from the larger in-plane wave number, that is, the surface plasmon mode (k _|| = 23.7 μm ⁻¹ ) concentrated on the back surface 18-1c of the metal layer 18-1. Since the energy is large, using the wave number (propagation constant) of this surface plasmon, the hot water surface plasmon mode that concentrates on the back surface 18-1c of the metal layer 18-1 is obtained from the above equations (10) and (1). When the corresponding fine structure (that is, a two-dimensional lattice structure) was calculated, the particle diameter D of the particle was calculated to be 306 nm.

Based on the particle diameter D of the particle thus calculated, colloidal silica having an average reasoning system of 298.7 nm and a particle polarization coefficient of 4.0% is used in the same manner as the organic light emitting diode 10 according to the first embodiment. The microstructure was made by the method.

  When one surface of the substrate 12 after the fine structure was produced was observed with an AFM, the cross-sectional shape was a truncated cone shape, and the fine structure in which the convex portions were arranged in a triangular lattice shape was formed.

  Thus, when the center distance p ′ (lattice constant) of the convex portion in the fine structure formed on one surface of the substrate 12 was measured by AFM, the average value of three tests was 307.6 nm. there were.

  Further, the average value of the convex portions of the fine structure in the 25 μm × 5 μm regions randomly selected from the AFM image was calculated, and the average value of each of the 25 locations was further averaged. The average height h of the convex portions in the fine structure was 51.8 nm.

  Furthermore, as a result of calculation using the above equation (13), the displacement S of the arrangement was 3.0%.

Furthermore, the ratio of the average height h to the average value of the center distance p ′ (average height h / center distance p ′) was 0.168.

  Thereafter, Al is deposited as a reflective layer 22 with a thickness of 100 nm on one surface of the substrate 12 on which the microstructure is formed, and IZO is deposited as a positive electrode conductive layer 14 on the reflective layer 22 with a thickness of 20 nm. Then, a HAT-CN film having a thickness of 40 nm was formed as a hole injection layer 16-1 by a vapor deposition method.

Next, T400 is deposited as a hole transport layer 16-2 on the hole injection layer 16-1 by a vapor deposition method with a thickness of 50 nm, and then ADN doped with 7% MDP3FL on the hole transport layer 16-2. The formed light emitting layer 16-3a having a thickness of 20 nm, the light emitting layer 16-3b having a thickness of 2 nm formed by Alq ₃ doped with 1% C545T, and Ir (piq) ₃ doped with 8.5% CBP. The light emitting layer 16-3c having a thickness of 10 nm formed by the above method was formed by vapor deposition.

  Further, E913 was deposited on the light-emitting layer 16-3 as an electron transport layer 16-4 by a vapor deposition method with a thickness of 30 nm. Furthermore, on the electron transport layer 16-4, Al was formed as a metal layer 18-1. The organic light emitting diode 70 is formed by depositing IZO with a thickness of 110 nm on the metal layer 18-1 as a transparent conductive layer 18-2 on the metal layer 18-1. Produced.

In addition, the light emission area was produced in 2 * 2 mm by using a mask in the case of vapor deposition and sputtering.

  Next, a third embodiment of the organic light emitting diode according to the present invention will be described with reference to FIG.

  FIG. 7 is a schematic structural explanatory diagram of an organic light emitting diode according to a third embodiment of the present invention.

  In the description of the organic light emitting diode 50 shown in FIG. 7, for convenience of explanation, the upper surface in the height direction of each layer constituting the organic light emitting diode 50 is appropriately referred to as the upper surface, and the lower side in the height direction of each layer. The surface of is appropriately referred to as the lower surface.

Further, in the following description, as long as the present invention is used, the structure and method of the target organic light emitting diode are not necessarily limited.

  The organic light emitting diode 50 shown in FIG. 7 is a type of organic light emitting diode called a bottom emission type, and an anode conductive layer 54, an organic EL layer 56, and a cathode conductive layer 58 are sequentially stacked on a substrate 52. Yes.

  A voltage can be applied to the anode conductive layer 54 and the cathode conductive layer 58 by the power supply 20.

  In this organic light emitting diode 50, when a voltage is applied to the anode conductive layer 54 and the cathode conductive layer 58, holes are injected from the anode conductive layer 54 into a light emitting layer 56-3 (described later) in the organic EL layer 56. In addition, electrons are injected from the cathode conductive layer 58 to the light emitting layer 56-3 (described later) in the organic EL layer 56, and light generated in the organic EL layer 56 is extracted from the anode conductive layer 54 side. .

The organic light emitting diode 50 according to the third embodiment of the present invention is an organic light emitting diode called a three-wavelength bottom emission type, and the light emitting layer 56-3 includes three organic light emitting materials (light emitting elements). A layer 56-3a, a light emitting layer 56-3b, and a light emitting layer 56-3c, the details of which will be described later). Hereinafter, when there is no problem, the three layers are collectively described as the light emitting layer 56-3.

  The anode conductive layer 54 is connected to the anode of the power supply 20 and is made of a transparent conductive material that transmits visible light, like the anode conductive layer 14 in the organic light emitting diode 10 described above.

  Such a transparent conductive material is not particularly limited, and a known transparent conductive material can be used.

  Specifically, examples of the transparent conductive material used for the anode conductive layer 54 include ITO, ZnO, and ZTO.

Further, the thickness of the anode conductive layer 54 is preferably, for example, 50 to 200 nm.

  In addition, the organic EL layer 56 is similar to the organic EL layer 16 in the organic light emitting diode 10 described above, and a hole injection layer 56-1 into which holes are injected from the power supply 20 and a hole injected into the hole injection layer 56-1. And a hole transport layer 56-2 that blocks electrons from the light emitting layer 56-3, and a plurality of organic light emitting materials that emit light having different wavelengths. A light emitting layer 56-3 that emits light by combining holes transported from the hole transport layer 56-2 and electrons transported from an electron transport layer 56-4 described later, and injection in an electron injection layer 56-5 described later An electron transport layer 56-4 for transporting the emitted electrons to the light emitting layer 56-3 and blocking holes from the light emitting layer 56-3, and an electron injection layer for injecting electrons from the power source 20 6-5 is composed of a.

  The light emitting layer 56-3 includes a light emitting layer 56-3a made of an organic light emitting material that emits light of a predetermined wavelength, and an organic light emitting device that emits light having a wavelength different from that of the organic light emitting material forming the light emitting layer 56-3a. A light emitting layer 56-3b made of a material, and a light emitting layer 56-3c made of an organic light emitting material that emits light having a wavelength different from that of the organic light emitting material forming the light emitting layers 56-3a and 56-3b. ing. The organic light emitting material is selected so that the light emitting layers 56-3a, 56-3b, and 56-3c emit light to emit white light from the light emitting layer 56-3.

  The organic EL layer 56 is formed on the anode conductive layer 54 with a hole injection layer 56-1, a hole transport layer 56-2, a light emitting layer 56-3 (light emitting layer 56-3a, light emitting layer 56-3b, light emitting layer 56). -3c), the electron transport layer 56-4, and the electron injection layer 56-5 are laminated in this order.

  Note that these layers may have a single role or may have two or more roles. For example, the electron transport layer 56-4 and the light emitting layer 56-3c may serve as one layer. It is also possible.

That is, the organic EL layer 56 may be a layer including at least a light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c) containing an organic light emitting material, and the light emitting layer 56-3 ( The light emitting layers 56-3a, 56-3b, and 56-3c) may be configured only, but generally, layers other than the light emitting layer 56-3 are included. Such a layer other than the light emitting layer 56-3 is inorganic even if it is composed of an organic material as long as the function of the light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c) is not impaired. It may be composed of a material.

  In the present embodiment, the organic EL layer 56 includes a hole injection layer 56-1, a hole transport layer 56-2, a light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c), and an electron transport layer. It was assumed to be composed of five layers 56-4 and an electron injection layer 56-5. Among these layers, the most important layer is the light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c). For example, the hole injection layer 56-1 and the electron injection layer 56-5 are It can be omitted. The electron transport layer 56-4 can also serve as the light emitting layer 56-3.

  Here, the material which comprises each layer of the organic EL layer 56 is not specifically limited, A well-known thing can be used.

That is, as a material constituting the light emitting layer 56-3 (that is, the light emitting layers 56-3a, 56-3b, and 56-3c), an organic light emitting material is used. As such an organic light emitting material, for example, Ir (piq) ₃ , DPAVB, ZnPBO, C545T, and the like can be given.

Moreover, you may use what doped the fluorescent pigment | dye compound and the phosphorescence-emitting material to another substance (host material). In this case, as the host material, a material constituting the hole transport layer 56-2, a material constituting the electron transport layer 56-4, or a dedicated host material is used.

  As materials constituting the hole injection layer 56-1, the hole transport layer 56-2, and the electron transport layer 56-4, organic materials are generally used.

  Examples of the material constituting the hole injection layer 56-1 include compounds such as 2-TNATA and HAT-CN.

  Moreover, as a material which comprises the hole transport layer 56-2, aromatic amine compounds, such as NPD, CuPc, and TPD, etc. are mentioned, for example.

  Furthermore, as a material which comprises the electron carrying layer 56-4, oxadiol type compounds, such as BND and PBD, metal complex type compounds, such as Alq, etc. are mentioned, for example.

  Furthermore, examples of the material constituting the electron injection layer 56-5 include LiF.

  When such an electron injection layer 56-5 is provided between the electron transport layer 56-4 and the cathode conductive layer 58, a difference in work function can be reduced, and electrons are transferred from the cathode conductive layer 58 to the electron transport layer 56-4. Will be easier to migrate.

The overall thickness of the organic EL layer 56 is preferably, for example, 150 to 500 nm.

  The cathode conductive layer 58 is connected to the cathode of the power source 20 and is made of a metal material.

  Examples of the metal material include Ag, an alloy having an Ag content of 10% or more, Al or an alloy having an Al content of 10% or more, and the alloy includes, for example, Mg / Ag = 10/90. When such a magnesium alloy is used, the electron injection effect can be obtained without providing the electron injection layer 56-5.

The thickness of the cathode conductive layer 58 is preferably sufficiently thick so that light does not transmit to the air side (that is, the upper surface of the cathode conductive layer 58 and the surface 58a side of the cathode conductive layer 58). For example, 100 to 200 nm is preferable.

  The substrate 52 is made of a transparent material that transmits visible light. The material constituting the substrate 52 may be an inorganic material or an organic material, or a combination thereof.

  Specifically, examples of the inorganic material constituting the substrate 52 include alkali glass such as quartz glass, alkali-free glass and soda lime glass, various glasses such as white plate glass, and transparent inorganic minerals such as mica. Examples of the organic material constituting the substrate 52 include resin films such as cycloolefin films and polyester films, and fiber reinforced plastic materials in which fine fibers such as cellulose nanofibers are mixed in the resin film.

  A surface 52a on the side of the substrate 52 on which the anode conductive layer 54 is laminated (that is, the upper surface of the substrate 52) is provided with a two-dimensional lattice structure in which a plurality of convex portions 52b are periodically arranged in two dimensions. It has been.

  Such a two-dimensional lattice structure is formed in accordance with the surface plasmon wavelength corresponding to the peak wavelength of the emission spectrum of a material having a low internal quantum efficiency or a short lifetime.

  Then, the anode conductive layer 54, the organic EL layer 56, and the cathode conductive layer 58 are sequentially laminated on the substrate 52 on which the two-dimensional lattice structure is formed, so that the surface of each layer (that is, the upper surface of each layer is the substrate) On the surface opposite to the side where 52 is located), a two-dimensional lattice structure with a plurality of convex portions similar to the surface 52a of the substrate 52 is formed.

  In addition, the back surface of each layer (that is, the lower surface of each layer and the surface on which the substrate 52 is located) has a structure in which the structure formed on the surface 52a of the substrate 52 is inverted, that is, a plurality of recesses. A periodically arranged structure, that is, a two-dimensional lattice structure with a plurality of recesses is formed.

  Specifically, focusing on the cathode conductive layer 58, the back surface 58c of the cathode conductive layer 58 (that is, the lower surface of the cathode conductive layer 58 and the surface on which the organic EL layer 56 is located) is a substrate. Thus, a structure in which the structure formed on the surface 52a of 52 is inverted, that is, a structure in which the plurality of recesses 58b are periodically arranged in two dimensions, that is, a two-dimensional lattice structure with the plurality of recesses 58b is formed.

  By providing the two-dimensional lattice structure in this manner, surface plasmons excited in the cathode conductive layer 58 are extracted as propagating light.

  That is, when the light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c) emits light from the light emitting molecule, near-field light is generated in the very vicinity. Since the distance between the light emitting layer 56-3 and the cathode conductive layer 58 is very short, the surface 58a and the back surface 58c of the cathode conductive layer 58 are converted into propagation type surface plasmons.

  Propagation-type surface plasmon on the surface of metal has a surface electromagnetic field accompanied by free-electron density waves generated by incident electromagnetic waves (such as near-field light).

In the case of a surface plasmon existing on a flat metal surface, the dispersion curve of the surface plasmon and the dispersion curve of light (spatial propagation light) do not intersect with each other, so that the energy of the surface plasmon cannot be extracted as light. On the other hand, when a lattice structure is formed on the metal surface, the dispersion curve of the surface plasmon diffracted by the lattice structure intersects with the dispersion curve of the spatial propagation light, and the surface plasmon is extracted as radiation light. Can do.

  In this way, since the internal quantum efficiency is low or it is possible to emit light with enhanced emission spectrum intensity of a material having a short lifetime by forming a two-dimensional lattice structure, the internal quantum efficiency is low. Or even if it is an organic luminescent material with a short lifetime, it is not necessary to apply an excessive applied voltage, and can improve light extraction efficiency, without shortening a lifetime.

  In such a two-dimensional lattice structure, for example, when focusing on the cathode conductive layer 58, the recesses 58b formed on the back surface 58c (that is, the lower surface of the cathode conductive layer 58) are two-dimensionally arranged, so that one-dimensional. The light extraction efficiency is higher than in the case (that is, the arrangement direction is one direction, for example, a structure in which a plurality of grooves are arranged in one direction).

Preferable specific examples of such a two-dimensional lattice structure include a square lattice structure and a triangular lattice structure, and a triangular lattice structure is particularly preferable. This is because the more the arrangement direction, the more the conditions for obtaining the diffracted light, and the surface plasmon can be diffracted with high efficiency.

  In order to form a triangular lattice structure in such a two-dimensional lattice structure, a particle monolayer film in which particles are arranged in a two-dimensional hexagonal close-packed configuration is formed, and dry etching is performed using the particle monolayer film as an etching mask. Thus, it can be easily obtained. A method of forming a triangular lattice structure using such a particle single layer film will be described later.

  The depth D2 of the recess 58b is 15 nm ≦ D2 ≦ 180 nm, preferably 30 nm ≦ D2 ≦ 100 nm. When D2 <15 nm or D2> 180 nm, the effect of improving the light extraction efficiency becomes insufficient.

  The range of the depth D2 of the recess 58b described above is based on the following reason.

  That is, when the depth D2 of the recess 58b is less than 15 nm (that is, when D2 <15 nm), it is impossible to generate a sufficient surface plasmon diffracted wave as a two-dimensional lattice structure, and the surface plasmon is used as radiation light. The effect of taking out decreases.

  Further, when the depth D2 of the recess 58b exceeds 180 nm (that is, when D2> 180 nm), the surface plasmon starts to have a localized type property and is not a propagation type, so that radiation light can be extracted. Efficiency is reduced. Further, in this case, when the anode conductive layer 54, the organic EL layer 56, and the cathode conductive layer 58 of the organic light emitting diode 50 are sequentially laminated, the anode conductive layer 54 and the cathode conductive layer 58 are formed because the irregularities are steep. This is not preferable because the possibility of a short circuit is increased.

  Since the depth D2 of the concave portion 58b is the same as the height H2 of the convex portion 52b formed on the surface 52a of the substrate 52, it is indirectly quantified by measuring the height of the convex portion 52b by AFM. be able to.

  For example, first, an AFM image was acquired for one randomly selected 5 μm × 5 μm region in a two-dimensional lattice structure, and then a line was drawn in the diagonal direction of the acquired AFM image, and intersected with this line The maximum height of the convex part 52b is calculated independently. Thereafter, an average value of the calculated heights of the convex portions 52b is calculated. These processes are similarly executed for a total of 25 randomly selected 5 μm × 5 μm regions, and the average value of the convex portions 52b in each region is calculated, and the average values in the obtained 25 regions are further averaged. The obtained value is defined as the height of the convex portion 52b.

The shape of the convex portion 52b is not particularly limited, and examples thereof include a columnar shape, a cone shape, a truncated cone shape, a sine wave shape, a dome shape, and a derivative shape based on them.

  Next, a method for manufacturing the organic light emitting diode 50 will be described. The method for manufacturing the organic light emitting diode 50 is not particularly limited. Preferably, the organic light emitting diode 50 is anode-conductive on the surface 52a of the substrate 52 having a plurality of convex portions 52b formed on the surface 52a in a two-dimensional lattice structure. Layer 54, organic EL layer 56 (hole injection layer 56-1, hole transport layer 56-2, light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c), electron transport layer 56-4. The electron injection layer 56-5) and the cathode conductive layer 58 are sequentially stacked.

  In this case, the two-dimensional lattice structure formed by the plurality of concave portions 58b formed on the back surface 58c of the cathode conductive layer 58 corresponds to the two-dimensional lattice structure formed by the plurality of convex portions 52b formed on the front surface 52a of the substrate 52. (See FIGS. 2A and 2B).

  That is, the center-to-center distance P3 between adjacent recesses 58b in the plurality of recesses 58b formed on the back surface 58c of the cathode conductive layer 58 (hereinafter referred to as “center-to-center distance P3 between adjacent recesses 58b” is referred to as “center of the recess 58b”). The inter-center distance P4 between the adjacent convex portions 52b of the plurality of convex portions 52b formed on the surface 52a of the substrate 52 (hereinafter referred to as “between adjacent convex portions 52b”). The center-to-center distance P4 "is referred to as" the center-to-center distance P4 of the convex portion 52b "), and the depth D2 of the concave portion 58b is equal to the height H2 of the convex portion 52b.

  Therefore, the center P4 of the concave portion 58b formed on the back surface 58c of the cathode conductive layer 58 is measured by measuring the distance P4 between the centers of the convex portions 52b formed on the front surface 52a of the substrate 52 and the height H2 of the convex portions 52b. The distance P3 and the depth D2 of the recess 58b can be measured.

  The center-to-center distance P3 of the concave portion 58b can be indirectly measured by measuring the center-to-center distance P4 of the convex portion 52b by a laser diffraction method, and the depth D2 of the concave portion 58b is The height H2 of 52b can be indirectly measured by measuring with the AFM.

Hereinafter, the manufacturing method of the organic light emitting diode 50 will be described in detail.

  First, a method for producing a two-dimensional lattice structure using a plurality of convex portions 52b formed on the surface 52a of the substrate 52 includes, for example, electron beam lithography, mechanical cutting, laser processing, two-beam interference exposure, reduced exposure, and the like. Can be used. In addition, if the original plate is prepared in advance, the fine structure can be transferred and duplicated by the nanoimprint method.

  Among these methods, methods other than the two-beam interference exposure and the nanoimprint method are not suitable for manufacturing a large-area periodic grating structure, and thus are limited in terms of industrial use.

  In addition, two-beam interference exposure can produce a small area to some extent, but in the case of a large area with a side of several centimeters or more, vibration, wind, thermal contraction, expansion, air fluctuation, wavelength for the entire optical setup It is extremely difficult to produce a uniform and accurate periodic grating structure due to various disturbance factors such as fluctuations.

  Therefore, as a method for producing a two-dimensional lattice structure with a plurality of convex portions 52b formed on the surface 52a of the substrate 52 in the organic light emitting diode 50, the plurality of convex portions 12b are formed on the organic light emitting diode 10 with a two-dimensional lattice structure. An etching method using a particle monolayer film used for forming is preferable.

  In addition, since the etching method using this particle | grain single layer film has been demonstrated above, suppose that the detailed processing content is abbreviate | omitted.

  Then, after a two-dimensional lattice structure is formed on the surface 52a of the substrate 52 by a plurality of convex portions 52b by an etching method using a particle single layer film, an anode conductive layer 54 is laminated on the surface 52a of the substrate 52. On the surface 54a of the anode conductive layer 54, a hole injection layer 56-1, a hole transport layer 56-2, a light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, 56-3c), an electron transport layer 56- 4. The organic EL layer 56 is formed by sequentially stacking the electron injection layer 56-5, and the cathode conductive layer 58 is stacked on the surface 56-5a of the electron injection layer 56-5, thereby obtaining the organic light emitting diode 50. can do.

  The lamination method of each of these layers is not particularly limited, and a known technique used for manufacturing a general organic light emitting diode can be used.

  For example, the anode conductive layer 54 can be formed by a sputtering method, a vacuum evaporation method, or the like. In addition, a hole injection layer 56-1, a hole transport layer 56-2, a light emitting layer 56-3 (light emitting layers 56-3a, 56-3b, and 56-3c), an electron transport layer 56-4, and an electron injection layer 56-5. Each of the cathode conductive layer 58 and the cathode conductive layer 58 can be formed by a vacuum deposition method.

Since the thickness of each of these layers is very thin, by sequentially laminating each layer as described above, the two-dimensional lattice structure by the plurality of convex portions 52b on the surface 52a of the substrate 52 is reflected to the cathode conductive layer 58, and the anode In the conductive layer 54, the organic EL layer 56, and the cathode conductive layer 58, a two-dimensional lattice structure is formed by a plurality of convex portions or concave portions corresponding to the two-dimensional lattice structure by the plurality of convex portions 52b formed on the surface 52a of the substrate 52. Will be.

  Next, the case where the organic light emitting diode 50 is manufactured based on the above-described manufacturing method will be described with a specific example.

As the organic light emitting diode 50 to be manufactured, substrate / IZO [film thickness 100 nm] / HAT-CN [film thickness 30 nm] / T400 [film thickness 50 nm] / MDP3FL @ ADN (7%) [film thickness 10 nm] / C545T @ Alq ₃ (1%) [film thickness 2 nm] / Ir (piq) ₃ @CBP (8.5%) [film thickness 10 nm] / E913 [film thickness 30 nm] / LiF [film thickness 0.8 nm] / Al [film thickness] 150 nm].

That is, the organic light emitting diode 50 includes a substrate 52 made of quartz glass, a 100 nm thick anode conductive layer 54 made of IZO, and a 30 nm thick hole injection layer 56-made of HAT-CN. 1, a 50 nm thick hole transport layer 56-2 formed by T400, a 10 nm thick light emitting layer 56-3a formed by ADN doped with 7% MDP3FL, and C545T 1% doped Alq ₃ The light emitting layer 56-3b having a thickness of 2 nm formed by the above, the light emitting layer 56-3c having a thickness of 10 nm formed by Ir (piq) ₃ doped with 8.5% CBP, and the thickness formed by E913 A 30 nm electron transport layer 56-4, a 0.8 nm thick electron injection layer 56-5 formed of LiF, and a thickness 15 of Al. It is constituted by the cathode conductive layer 58 nm.

Since the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials, the peak wavelength value λ ₁ of the emission spectrum to be enhanced is set to 630 nm.

  In order to fabricate the organic light emitting diode 50, first, the particle size of the particles that form the particle monolayer film required when creating a two-dimensional lattice structure with a plurality of convex portions 52b on the surface 52a of the substrate 52 is calculated. To do.

  That is, in the organic light emitting diode 50, the intensity of energy dissipation when the thickness of the cathode conductive layer 58 is assumed to be infinite is obtained by the above-described equations (7), (8), and (9).

  Here, the particle diameter of the particles forming the particle single layer film when the surface plasmon energy generated on the back surface 58c of the cathode conductive layer 58 is extracted as propagating light is calculated.

In the above equations (7), (8), and (9), the first mode (peak) from the larger wave number is the energy dissipation intensity of the surface plasmon generated on the back surface 58c of the cathode conductive layer 58. Then, the in-plane wave number k _||

  The position of the dipole is 35 nm from the back surface 58c of the cathode conductive layer 58 (that is, the distance from the upper interface to the lower interface in the light emitting layer 56-3c is equal).

  However, since the LiF layer is very thin, the thickness was set to “0” in the calculation. The thickness of the Al layer was infinite.

  Note that the above-mentioned non-patent literature is referred to as a formula for obtaining the reflection coefficient of the above-described ordinary multilayer thin film.

When the above equation (9) is calculated as a function having k _|| as a variable, a result as shown in FIG. 8 is obtained.

In FIG. 8, the first mode (that is, the peak R) from the one with the larger in-plane wave number, that is, the in-plane wave number k _|| that gives the energy dissipation peak to the surface plasmon is 17.8 μm ⁻¹ . It has become. By substituting this value into the above equation (10), the particle diameter D of the particle for producing a fine structure (that is, a two-dimensional lattice structure) corresponding to this wave number was calculated to be 407 nm. .

In this specific example, in order to explain the etching method using the particle monolayer film, the particle diameter of the particles forming the particle monolayer film is calculated using the above equation (10). When the organic light emitting diode 50 is manufactured by a method other than the etching method using the particle monolayer film, the lattice pitch P is calculated using the above-described equation (10) or (11) (note that the lattice pitch P Is a value in the range shown in the equation (1)), and may be prepared by adjusting various conditions so that the calculated lattice pitch P is obtained.

  Based on the value of the particle diameter D of the particle calculated by the above formula (10), 5.0 mass% water of colloidal silica having an average particle diameter of 398.7 nm and a particle diameter variation coefficient of 4.0%. A dispersion (dispersion) was prepared. The average particle diameter and the coefficient of variation of the particle were calculated from a peak obtained by fitting a particle size distribution obtained by a particle dynamic light scattering method using Zetasizer Nano-ZS manufactured by Malvern Instruments Ltd. to a Gaussian curve.

  Next, in order to hydrophobize the surface of the colloidal silica in the prepared dispersion, an aqueous solution containing a hydrolyzate of phenyltriethoxysilane having a concentration of 1.0% by mass is added to the dispersion, and about 40 °. The reaction was performed for 3 hours. At this time, the dispersion and the aqueous solution were mixed so that the mass of phenyltriethoxysilane was 0.015 times the mass of the colloidal silica particles.

Then, methyl isobutyl ketone having a volume five times that of the dispersion was added to the dispersion after the reaction and stirred to extract the hydrophobized colloidal silica in the oil phase.

  A hydrophobized colloidal silica dispersion liquid having a concentration of 1.05% by mass obtained in this manner includes a surface pressure sensor for measuring the surface pressure of the particle monolayer film, and a movable barrier for compressing the particle monolayer film in a direction along the liquid surface. It dropped at a drop rate of 0.01 ml / second onto the liquid surface (water was used as the lower layer liquid and the water temperature was 26.5 ° C.) stored in the water tank (LB trough device) provided. In the lower layer water stored in the water tank, a transparent quartz substrate (30 mm × 30 mm × 1.0 mm, double-sided mirror polished) to be used as the substrate 52 of the organic light emitting diode 50 in advance is immersed in a substantially vertical direction. ing.

  From the time when the hydrophobized colloidal silica dispersion liquid started dripping onto the surface of the lower layer water, it was made hydrophobic by irradiating with ultrasonic waves for 10 minutes from the lower layer water toward the liquid surface under the conditions of an output of 100 W and a frequency of 1500 kHz. The colloidal silica particles were promoted to be two-dimensionally closely packed, and methyl isobutyl ketone, which is the organic solvent in the dispersion, was volatilized to form a particle monolayer film on the liquid surface of the lower layer water.

Thereafter, the formed particle monolayer film is compressed by a movable barrier until the diffusion pressure becomes 22 to 30 mNm ⁻¹ , the substrate 52 is pulled up at a speed of 3 mm / min, and the particle monolayer film is formed on one surface of the substrate 52. Removed. Note that one surface of the substrate 52 is a surface on which a two-dimensional lattice structure is to be formed.

  Next, as a fixing process of the particle monolayer film transferred onto one surface of the substrate 52 to the one surface, 0.15 as a binder on one surface of the substrate 52 from which the particle monolayer film has been transferred. A hydrolyzate of mass% monomethyltrimethoxysilane was infiltrated, and then the excess of the hydrolyzate was removed by treatment with a spin coater (3000 rpm) for 1 minute. And the board | substrate 52 from which the excess part of the hydrolysis liquid was removed was heated at 100 degreeC for 10 minute (s), the binder was made to react, and the board | substrate 52 with which the particle | grain single layer film which consists of colloidal silica particles was formed was acquired.

When the substrate 52 on which the particle monolayer film was formed was obtained in this way, next, the substrate 52 was dry-etched with CHF ₃ gas.

The conditions for this dry etching process were an antenna power of 1500 W, a bias power of 50 to 300 W (13.56 MHz), and a gas flow rate of 50 to 200 sccm.

  When one surface of the substrate 52 after the dry etching process is observed with an AFM, the cross-sectional shape is a truncated cone shape (see FIG. 6B), and the planar arrangement is a triangular lattice shape. A fine structure arranged in a row was formed (see FIG. 6A).

  Thus, when the center distance p ′ (lattice constant) of the convex portion in the fine structure formed on one surface of the substrate 52 was measured by AFM, the average value of three tests was 413.5 nm. there were.

  Further, the average value of the convex portions of the fine structure in the 25 μm × 5 μm regions randomly selected from the AFM image was calculated, and the average value of each of the 25 locations was further averaged. The average height h of the convex portions in the fine structure was 45.1 nm.

  Furthermore, as a result of calculation using the above-described equation (13), the displacement S of the sequence was 3.7%.

Furthermore, the ratio of the average height h to the average value of the center distance p ′ (average height h / center distance p ′) was 0.109.

  Thereafter, on one surface of the substrate 52 on which the fine structure is formed, IZO is deposited as the anode conductive layer 54 with a thickness of 100 nm by a sputtering method, and HAT-CN is deposited as the hole injection layer 56-1 with a thickness of 30 nm. The film was formed by vapor deposition.

Next, a T400 film having a thickness of 50 nm is deposited on the hole injection layer 56-1 by a vapor deposition method as a hole transport layer 56-2, and then ADN doped with 7% MDP3FL on the hole transport layer 56-2. The formed light emitting layer 56-3a having a thickness of 10 nm, the light emitting layer 56-3b having a thickness of 2 nm formed of Alq ₃ doped with 1% of C545T, and Ir (piq) ₃ doped with 8.5% of CBP. The light emitting layer 56-3c having a thickness of 10 nm formed by the above method was formed by vapor deposition.

  Further, on the light emitting layer 56-3c, an electron transport layer 56-4 having a thickness of 30 nm formed by E913, an electron injection layer 56-5 having a thickness of 0.8 nm formed by LiF, and Al are formed. In addition, a 150 nm cathode conductive layer 58 was sequentially formed by vapor deposition to produce an organic light emitting diode 50.

In addition, the light emission area was produced in 2 * 2 mm by using a mask in the case of vapor deposition and sputtering.

  Next, a fourth embodiment of the organic light emitting diode according to the present invention will be described with reference to FIG.

  FIG. 9 is a schematic structural explanatory diagram of an organic light emitting diode according to a fourth embodiment of the present invention.

  In the description of the organic light emitting diode 60 shown in FIG. 9, for convenience of explanation, the upper surface in the height direction of each layer constituting the organic light emitting diode 60 is appropriately referred to as the upper surface, and the lower side in the height direction of each layer. The surface of is appropriately referred to as the lower surface.

Further, in the following description, as long as the present invention is used, the structure and method of the target organic light emitting diode are not necessarily limited.

  An organic light emitting diode 60 shown in FIG. 9 is an organic light emitting diode of a type generally referred to as a three-wavelength type anode top emission type. A cathode conductive layer 64, an organic EL layer 66, an anode conductive layer 68, and the like are formed on a substrate 62. Are sequentially stacked.

  A voltage can be applied to the cathode conductive layer 64 and the anode conductive layer 68 by the power supply 20.

  In this organic light emitting diode 60, when a voltage is applied to the cathode conductive layer 64 and the anode conductive layer 68, holes are injected from the anode conductive layer 68 into a light emitting layer 66-3 (described later) in the organic EL layer 66. In addition, electrons are injected from the cathode conductive layer 64 into the light emitting layer 66-3 (described later) in the organic EL layer 66, and light generated in the organic EL layer 66 is extracted from the anode conductive layer 68 side. .

The organic light emitting diode 60 according to the fourth embodiment of the present invention is an organic light emitting diode called a three-wavelength anode top emission type, and the light emitting layer 66-3 includes three organic light emitting materials ( A light emitting layer 66-3a, a light emitting layer 66-3b, and a light emitting layer 66-3c, the details of which will be described later). Hereinafter, when the light emitting layer 66-3 is collectively described and there is no problem, the above three layers are described as the light emitting layer 66-3.

  The cathode conductive layer 64 is connected to the cathode of the power source 20 and is made of a metal material.

  The metal material is composed of Ag, an alloy having an Ag content of 10% or more, Al or an alloy having an Al content of 10% or more. Examples of the alloy include the above-described Mg / Ag = 10/90. And magnesium alloys.

The thickness of the cathode conductive layer 64 is preferably sufficiently thick so that the light from the organic EL layer is reflected and the light is not extracted from the substrate 62, and is preferably 100 to 200 nm, for example.

  Similarly to the organic EL layer 16 in the organic light emitting diode 10 described above, the organic EL layer 66 includes a hole injection layer 66-1 into which holes are injected from the power supply 20, and a hole injected into the hole injection layer 66-1. A hole transport layer 66-2 that blocks electrons from the light emitting layer 66-3, and a plurality of organic light emitting materials that emit light having different wavelengths. A light emitting layer 66-3 that emits light by combining holes transported from the hole transport layer 66-2 and electrons transported from the electron transport layer 66-4 described later, and injection in an electron injection layer 66-5 described later An electron transport layer 66-4 for transporting the emitted electrons to the light emitting layer 66-3 and blocking holes from the light emitting layer 66-3, and an electron injection layer for injecting electrons from the power source 20 6-5 is composed of a.

  The light emitting layer 66-3 includes a light emitting layer 66-3a made of an organic light emitting material that emits light of a predetermined wavelength, and an organic light emitting that emits light of a wavelength different from that of the organic light emitting material forming the light emitting layer 66-3a. A light emitting layer 66-3b made of a material, and a light emitting layer 66-3c made of an organic light emitting material that emits light having a wavelength different from that of the organic light emitting material forming the light emitting layers 66-3a and 66-3b. ing. The light emitting layers 66-3a, 66-3b, and 66-3c are selected so that white light is emitted from the light emitting layer 66-3 by emitting light.

  The organic EL layer 66 is formed on the cathode conductive layer 64 with an electron injection layer 66-5, an electron transport layer 66-4, a light emitting layer 66-3 (light emitting layer 66-3c, light emitting layer 66-3b, light emitting layer 66). -3a), a hole transport layer 66-2, and a hole injection layer 66-1 are laminated in this order.

  Note that these layers may have a single role or may have two or more roles. For example, the electron transport layer 66-4 and the light-emitting layer 66-3c may serve as one layer. It is also possible.

That is, the organic EL layer 66 may be a layer including at least a light emitting layer 66-3 (light emitting layers 66-3a, 66-3b, 66-3c) containing an organic light emitting material, and the light emitting layer 66-3 ( The light emitting layers 66-3a, 66-3b, and 66-3c) may be used alone, but generally, layers other than the light emitting layer 66-3 are included. Such a layer other than the light emitting layer 66-3 is inorganic even if it is composed of an organic material as long as the function of the light emitting layer 66-3 (light emitting layers 66-3a, 66-3b, 66-3c) is not impaired. It may be composed of a material.

  In the present embodiment, the organic EL layer 66 includes a hole injection layer 66-1, a hole transport layer 66-2, a light emitting layer 66-3 (light emitting layers 66-3a, 66-3b, 66-3c), and an electron transport layer. 66-5 and the electron injection layer 66-5 were comprised. Among these layers, the most important layer is the light emitting layer 66-3 (light emitting layers 66-3a, 66-3b, 66-3c). For example, the hole injection layer 66-1 and the electron injection layer 66-5 are It can be omitted. The electron transport layer 66-4 can also serve as the light emitting layer 66-3.

  Here, the material which comprises each layer of the organic EL layer 66 is not specifically limited, A well-known thing can be used.

That is, an organic light-emitting material is used as a material constituting the light-emitting layer 66-3 (that is, the light-emitting layers 66-3a, 66-3b, and 66-3c). Ir (piq) ₃ , DPAVB, ZnPBO, C545T, and the like can be given.

Moreover, you may use what doped the fluorescent pigment | dye compound and the phosphorescence-emitting material to another substance (host material). In this case, as the host material, a material constituting the hole transport layer 66-2, a material constituting the electron transport layer 66-4, or a dedicated host material is used.

  As materials constituting the hole injection layer 66-1, the hole transport layer 66-2, and the electron transport layer 66-4, organic materials are generally used.

  Examples of the material constituting the hole injection layer 66-1 include compounds such as 2-TNATA and HAT-CN.

  Moreover, as a material which comprises the hole transport layer 66-2, aromatic amine compounds, such as NPD, CuPc, and TPD, etc. are mentioned, for example.

  Furthermore, as a material which comprises the electron carrying layer 66-4, oxadiol type compounds, such as BND and PBD, metal complex type compounds, such as Alq, etc. are mentioned, for example.

  Furthermore, examples of the material constituting the electron injection layer 66-5 include LiF.

  When such an electron injection layer 66-5 is provided between the electron transport layer 66-4 and the cathode conductive layer 64, the work function difference can be reduced, and electrons are transferred from the cathode conductive layer 64 to the electron transport layer 66-4. Will be easier to migrate.

  If a magnesium alloy such as Mg / Ag = 10/90 is used as the cathode conductive layer 64, the electron injection effect can be obtained without providing the electron injection layer 66-5.

For example, the thickness of the entire organic EL layer is preferably 150 to 500 nm.

  In addition, the anode conductive layer 68 is connected to the anode of the power source 20 and is a transparent conductive material that transmits visible light, like the anode conductive layer 14 in the organic light emitting diode 10 and the anode conductive layer 54 in the organic light emitting diode 50 described above. It is composed of materials.

  Such a transparent conductive material is not particularly limited, and a known transparent conductive material can be used.

  Specifically, examples of the transparent conductive material used for the anode conductive layer 68 include ITO, ZnO, and ZTO.

Further, the thickness of the anode conductive layer 68 is preferably, for example, 50 to 200 nm.

  The substrate 62 is made of a transparent material that transmits visible light or an opaque material that does not transmit visible light. The material constituting the substrate 62 may be an inorganic material or an organic material, or a combination thereof. .

  Specifically, as the material constituting the substrate 62, the transparent inorganic material includes quartz glass, alkali-free glass such as alkali-free glass and soda lime glass, various glasses such as white plate glass, and transparent inorganic minerals such as mica. Examples of the opaque inorganic material include metals such as aluminum, nickel, and stainless steel, and various ceramics.

  Examples of the organic material include resin films such as cycloolefin films and polyester films, and fiber reinforced plastic materials in which fine fibers such as cellulose nanofibers are mixed in the resin film. As for the organic material, both a transparent body and an opaque body can be used.

  On the surface 62a of the substrate 62 on the side where the cathode conductive layer 64 is laminated (that is, the upper surface of the substrate 62), a two-dimensional lattice structure in which a plurality of convex portions 62b are periodically arranged in two dimensions is provided. It has been.

Such a two-dimensional lattice structure is formed in accordance with the wavelength of the surface plasmon corresponding to the peak wavelength of the emission spectrum of a material having a low internal quantum efficiency or a short lifetime.

  Then, the cathode conductive layer 64, the organic EL layer 66, and the anode conductive layer 68 are sequentially laminated on the substrate 62 on which the two-dimensional lattice structure is formed, so that the surface of each layer (that is, the upper surface of each layer, On the surface opposite to the side where 62 is located), a two-dimensional lattice structure with a plurality of convex portions similar to the surface 62a of the substrate 62 is formed.

  In addition, the back surface of each layer (that is, the lower surface of each layer and the surface on which the substrate 62 is located) has a structure in which the structure formed on the surface 62a of the substrate 62 is inverted, that is, a plurality of recesses. A periodically arranged structure, that is, a two-dimensional lattice structure with a plurality of recesses is formed.

  Specifically, when attention is paid to the cathode conductive layer 64, the surface 64 a of the cathode conductive layer 64 (that is, the upper surface of the cathode conductive layer 64 and the surface on which the organic EL layer 66 is located) is disposed on the substrate. A structure similar to the structure formed on the surface 62a of 62, that is, a structure in which a plurality of convex portions 64b are periodically arranged in two dimensions, that is, a two-dimensional lattice structure formed by the plurality of convex portions 64b; Become.

  By providing the two-dimensional lattice structure in this way, surface plasmons excited in the cathode conductive layer 64 are extracted as propagating light.

  That is, when the light emitting layer 66-3 (the light emitting layers 66-3a, 66-3b, 66-3c) emits light from the light emitting molecule, near-field light is generated in the very vicinity. Since the distance between the light emitting layer 66-3 and the cathode conductive layer 64 is very short, the surface 64a of the cathode conductive layer 64 is converted into a propagation type surface plasmon.

  Propagation-type surface plasmon on the surface of metal has a surface electromagnetic field accompanied by free-electron density waves generated by incident electromagnetic waves (such as near-field light).

In the case of a surface plasmon existing on a flat metal surface, the dispersion curve of the surface plasmon and the dispersion curve of light (spatial propagation light) do not intersect with each other, so that the energy of the surface plasmon cannot be extracted as light. On the other hand, when a lattice structure is formed on the metal surface, the dispersion curve of the surface plasmon diffracted by the lattice structure intersects with the dispersion curve of the spatial propagation light, and the surface plasmon is extracted as radiation light. Can do.

  In this way, since the internal quantum efficiency is low or it is possible to emit light with enhanced emission spectrum intensity of a material having a short lifetime by forming a two-dimensional lattice structure, the internal quantum efficiency is low. Or even if it is an organic luminescent material with a short lifetime, it is not necessary to apply an excessive applied voltage, and can improve light extraction efficiency, without shortening a lifetime.

  In such a two-dimensional lattice structure, for example, when focusing on the cathode conductive layer 64, the convex portions 64b formed on the surface 64a (that is, the upper surface of the cathode conductive layer 64) are arranged in a two-dimensional manner. The light extraction efficiency is higher than in the original case (that is, the arrangement direction is one direction, for example, a structure in which a plurality of grooves are arranged in one direction).

Preferable specific examples of such a two-dimensional lattice structure include a square lattice structure and a triangular lattice structure, and a triangular lattice structure is particularly preferable. This is because the more the arrangement direction, the more the conditions for obtaining the diffracted light, and the surface plasmon can be diffracted with high efficiency.

  In order to form a triangular lattice structure in such a two-dimensional lattice structure, a particle monolayer film in which particles are arranged in a two-dimensional hexagonal close-packed configuration is formed, and dry etching is performed using the particle monolayer film as an etching mask. Thus, it can be easily obtained. A method of forming a triangular lattice structure using such a particle single layer film will be described later.

  The height H4 of the convex portion 64b is set to 15 nm ≦ H4 ≦ 180 nm, preferably 30 nm ≦ H4 ≦ 100 nm. When H4 <15 nm or H4> 180 nm, the effect of improving the light extraction efficiency becomes insufficient.

  The range of the height H4 of the convex part 64b described above is based on the following reason.

  That is, when the height H4 of the convex portion 64b is less than 15 nm (that is, when H4 <15 nm), it becomes impossible to generate a sufficient surface plasmon diffracted wave as a two-dimensional lattice structure, and the surface plasmon is irradiated with radiation. As a result, the effect of taking out decreases.

  Further, when the height H4 of the convex portion 64b exceeds 180 nm (that is, when H4> 180 nm), the surface plasmon begins to have a localized type property and is no longer a propagation type. The extraction efficiency decreases. Further, in this case, when the cathode conductive layer 64, the organic EL layer 66, and the anode conductive layer 68 of the organic light emitting diode 60 are sequentially laminated, the cathode conductive layer 64 and the anode conductive layer 68 are formed because the irregularities are steep. This is not preferable because the possibility of a short circuit is increased.

  Since the height H4 of the convex portion 64b is the same as the height H3 of the convex portion 62b formed on the surface 62a of the substrate 62, the height H4 of the convex portion 62b is measured indirectly by AFM. can do.

  For example, first, an AFM image was acquired for one randomly selected 5 μm × 5 μm region in a two-dimensional lattice structure, and then a line was drawn in the diagonal direction of the acquired AFM image, and intersected with this line The maximum height of the convex part 62b is calculated independently. Then, the average value of the height of the calculated convex part 62b is calculated. These processes are similarly performed on a total of 25 randomly selected 5 μm × 5 μm regions, the average value of the convex portions 62b in each region is calculated, and the average value in the obtained 25 regions is further averaged The obtained value is defined as the height of the convex portion 62b.

The shape of the convex portion 62b is not particularly limited, and examples thereof include a columnar shape, a cone shape, a truncated cone shape, a sine wave shape, a dome shape, and a derivative shape based on them.

  Next, a method for manufacturing the organic light emitting diode 60 will be described. The method for manufacturing the organic light emitting diode 60 is not particularly limited. Preferably, the organic light emitting diode 60 is cathodically conductive on the surface 62a of the substrate 62 having a plurality of convex portions 62b formed on the surface 62a in a two-dimensional lattice structure. Layer 64, organic EL layer 66 (electron injection layer 66-5, electron transport layer 66-4, light emitting layer 66-3 (light emitting layers 66-3c, 66-3b, 66-3a), hole transport layer 66-2 The hole injection layer 66-1) and the anode conductive layer 68 are sequentially stacked.

  In this case, the two-dimensional lattice structure formed by the plurality of protrusions 64b formed on the surface 64a of the cathode conductive layer 64 corresponds to the two-dimensional lattice structure formed by the plurality of protrusions 62b formed on the surface 62a of the substrate 62. Become.

  That is, the center-to-center distance P5 between the adjacent protrusions 64b in the plurality of protrusions 64b formed on the surface 64a of the cathode conductive layer 64 (hereinafter referred to as “the center-to-center distance P5 between the adjacent protrusions 64b” is referred to as “protrusion”. Is referred to as a center-to-center distance P5 of the portion 64b.) Is a center-to-center distance P6 between the adjacent protrusions 62b of the plurality of protrusions 62b formed on the surface 62a of the substrate 62 (hereinafter referred to as “adjacent protrusions”). The center-to-center distance P6 between the parts 62b is referred to as “the center-to-center distance P6 of the convex part 62b”), and the height H4 of the convex part 64b is equal to the height H3 of the convex part 62b. It will be a thing.

  Therefore, by measuring the distance P6 between the centers of the protrusions 62b formed on the surface 62a of the substrate 62 and the height H3 of the protrusions 62b, the protrusions 64b formed on the surface 64a of the cathode conductive layer 64 are measured. The center distance P5 and the height H4 of the convex portion 64b can be measured.

  Note that the center-to-center distance P5 of the protrusions 64b can be indirectly measured by measuring the center-to-center distance P6 of the protrusions 62b by a laser diffraction method, and the height H4 of the protrusions 64b is The height H3 of the convex portion 62b can be indirectly measured by measuring with the AFM.

Hereinafter, the manufacturing method of the organic light emitting diode 60 will be described in detail.

  First, a method for producing a two-dimensional lattice structure using a plurality of convex portions 62b formed on the surface 62a of the substrate 62 includes, for example, electron beam lithography, mechanical cutting, laser processing, two-beam interference exposure, reduced exposure, and the like. Can be used. In addition, if the original plate is prepared in advance, the fine structure can be transferred and duplicated by the nanoimprint method.

  Among these methods, methods other than the two-beam interference exposure and the nanoimprint method are not suitable for manufacturing a large-area periodic grating structure, and thus are limited in terms of industrial use.

  In addition, two-beam interference exposure can produce a small area to some extent, but in the case of a large area with a side of several centimeters or more, vibration, wind, thermal contraction, expansion, air fluctuation, wavelength for the entire optical setup It is extremely difficult to produce a uniform and accurate periodic grating structure due to various disturbance factors such as fluctuations.

  Therefore, as a method for producing a two-dimensional lattice structure with a plurality of convex portions 62b formed on the surface 62a of the substrate 62 in the organic light emitting diode 60, the organic light emitting diode 10 has a plurality of convex portions 12b with a two-dimensional lattice structure. An etching method using a particle monolayer film used for forming is preferable.

  In addition, since the etching method using this particle | grain single layer film has been demonstrated above, suppose that the detailed processing content is abbreviate | omitted.

  Then, after a two-dimensional lattice structure is formed on the surface 62a of the substrate 62 by a plurality of convex portions 62b by an etching method using a particle single layer film, a cathode conductive layer 64 is laminated on the surface 62a of the substrate 62. On the surface 64a of the cathode conductive layer 64, an electron injection layer 66-5, an electron transport layer 66-4, a light emitting layer 66-3 (light emitting layers 66-3c, 66-3b, 66-3a), a hole transport layer 66- 2. The organic EL layer 66 is formed by sequentially laminating the hole injection layer 66-1, and the organic light emitting diode 60 is obtained by laminating the anode conductive layer 68 on the surface 66-1a of the hole injection layer 66-1. can do.

  The lamination method of each of these layers is not particularly limited, and a known technique used for manufacturing a general organic light emitting diode can be used.

  For example, a hole injection layer 66-1, a hole transport layer 66-2, a light emitting layer 66-3 (light emitting layers 66-3a, 66-3b, 66-3c), an electron transport layer 66-4, an electron injection layer 66-5. Each of the cathode conductive layer 64 and the cathode conductive layer 64 can be formed by a vacuum deposition method. The anode conductive layer 68 can be formed by a sputtering method, a vacuum evaporation method, or the like.

Since the thickness of each of these layers is very thin, by sequentially laminating each layer as described above, the two-dimensional lattice structure by the plurality of convex portions 62b on the surface 62a of the substrate 62 is reflected to the anode conductive layer 68, and the cathode In the conductive layer 64, the organic EL layer 66, and the anode conductive layer 68, a two-dimensional lattice structure is formed by a plurality of convex portions or concave portions corresponding to the two-dimensional lattice structure by the plurality of convex portions 62b formed on the surface 62a of the substrate 62. Will be.

  Next, a case where the organic light emitting diode 60 is manufactured based on the above-described manufacturing method will be described with a specific example.

As the organic light emitting diode 60 to be manufactured, Ir (piq) ₃ was doped at 8.5% concentration in substrate / Ag [film thickness 100 nm] / LiF [film thickness 0.8 nm] / E913 [film thickness 40 nm] / CBP. [Thickness 15 nm] / Alq ₃ doped with C545T at a concentration of 1% [Thickness 3 nm] / ADN doped with MDP3FL at a concentration of 7% [Thickness 30 nm] / T400 [Thickness 40 nm] / MoO _x (x = 1 to 3) [film thickness 60 nm] / IZO [film thickness 100 nm].

That is, the organic light emitting diode 60 includes a substrate 62 made of quartz glass, a cathode conductive layer 64 made of Ag with a thickness of 100 nm, and an electron injection layer 66-with a thickness of 0.8 nm made of LiF. 5; an electron transport layer 66-4 having a thickness of 40 nm formed by E913; a light emitting layer 66-3c having a thickness of 15 nm formed by Ir (piq) ₃ doped with 8.5% CBP; and C545T. Light emitting layer 66-3b with a thickness of 3 nm formed by Alq ₃ doped with 1%, light emitting layer 66-3a with a thickness of 30 nm formed by ADN doped with 7% of MDP3FL, and a thickness formed by T400 A 40 nm hole transport layer 66-2, a 60 nm thick hole injection layer 66-1 formed by MoO _x (x = 1 to 3), and IZO. And an anode conductive layer 68 having a thickness of 100 nm.

Since the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials, the peak wavelength value λ ₁ of the emission spectrum to be enhanced is set to 470 nm.

  In order to fabricate the organic light emitting diode 60, first, the particle size of the particles that form the particle monolayer film required when creating the two-dimensional lattice structure with the plurality of convex portions 62b on the surface 62a of the substrate 62 is calculated. To do.

  That is, in the organic light emitting diode 60, the intensity of energy dissipation when the thickness of the cathode conductive layer 64 is assumed to be infinite is obtained by the above-described equations (7), (8), and (9).

Here, the particle diameter of the particles forming the particle single layer film when the surface plasmon energy generated on the surface 64a of the cathode conductive layer 64 is extracted as propagating light is calculated.

  The position of the dipole is 73 nm from the surface 64 a of the cathode conductive layer 64.

As numerical values to be substituted into the above equations (7) and (8), d ₊ = 15 nm and d ₋ = 15 nm. However, since the LiF layer is very thin, the thickness was set to “0” in the calculation.

  Note that the above-mentioned non-patent literature is referred to as a formula for obtaining the reflection coefficient of the above-described ordinary multilayer thin film.

When the above equation (9) is calculated as a function having k _|| as a variable, a result as shown in FIG. 11 is obtained.

In FIG. 11, the first mode (that is, peak O) from the larger in-plane wave number is the energy dissipation intensity of the surface plasmon generated on the surface 64 a of the cathode conductive layer 64. The in-plane wave number k _|| which gives the energy dissipation peak to the surface plasmon mode is 31.6 μm ⁻¹ . When this value is substituted into the above equation (10), the particle diameter D of the particle for producing a fine structure corresponding to this wave number (that is, a two-dimensional lattice structure) was calculated to be 229 nm. .

In this specific example, in order to explain the etching method using the particle monolayer film, the particle diameter of the particles forming the particle monolayer film is calculated using the above equation (10). When the organic light emitting diode 60 is produced by a method other than the etching method using the particle monolayer film, the lattice pitch P is calculated using the above-described equation (10) or (11) (note that the lattice pitch P Is a value in the range shown in the equation (1)), and may be prepared by adjusting various conditions so that the calculated lattice pitch P is obtained.

Based on the value of the particle diameter D of the particle calculated by the above formula (10), 5.0 mass% water of colloidal silica having an average particle diameter of 232.0 nm and a coefficient of variation of the particle diameter of 4.0%. A dispersion (dispersion) was prepared. The average particle diameter and the coefficient of variation of the particle were calculated from a peak obtained by fitting a particle size distribution obtained by a particle dynamic light scattering method using Zetasizer Nano-ZS manufactured by Malvern Instruments Ltd. to a Gaussian curve.

  Next, in order to hydrophobize the surface of the colloidal silica in the prepared dispersion, an aqueous solution containing a hydrolyzate of phenyltriethoxysilane having a concentration of 1.0% by mass is added to the dispersion, and about 40 °. The reaction was performed for 3 hours. At this time, the dispersion and the aqueous solution were mixed so that the mass of phenyltriethoxysilane was 0.015 times the mass of the colloidal silica particles.

Then, methyl isobutyl ketone having a volume five times that of the dispersion was added to the dispersion after the reaction and stirred to extract the hydrophobized colloidal silica in the oil phase.

  A hydrophobized colloidal silica dispersion liquid having a concentration of 1.05% by mass obtained in this manner includes a surface pressure sensor for measuring the surface pressure of the particle monolayer film, and a movable barrier for compressing the particle monolayer film in a direction along the liquid surface. It dropped at a drop rate of 0.01 ml / second onto the liquid surface (water was used as the lower layer liquid and the water temperature was 26.5 ° C.) stored in the water tank (LB trough device) provided. In addition, a transparent quartz substrate (30 mm × 30 mm × 1.0 mm, double-sided mirror-polished) for use as the substrate 62 of the organic light emitting diode 60 is previously immersed in the lower layer water stored in the water tank in a substantially vertical direction. ing.

  From the time when the hydrophobized colloidal silica dispersion liquid started dripping onto the surface of the lower layer water, it was made hydrophobic by irradiating with ultrasonic waves for 10 minutes from the lower layer water toward the liquid surface under the conditions of an output of 100 W and a frequency of 1500 kHz. The colloidal silica particles were promoted to be two-dimensionally closely packed, and methyl isobutyl ketone, which is the organic solvent in the dispersion, was volatilized to form a particle monolayer film on the liquid surface of the lower layer water.

Thereafter, the formed particle monolayer film is compressed by a movable barrier until the diffusion pressure becomes 22 to 30 mNm ⁻¹ , the substrate 62 is pulled up at a speed of 3 mm / min, and the particle monolayer film is formed on one surface of the substrate 62. Removed. Note that one surface of the substrate 62 is a surface on which a two-dimensional lattice structure is to be formed.

  Next, as a fixing process of the particle single layer film transferred onto one surface of the substrate 62 to the one surface, 0.15 as a binder on one surface of the substrate 62 transferred with the particle single layer film. A hydrolyzate of mass% monomethyltrimethoxysilane was infiltrated, and then the excess of the hydrolyzate was removed by treatment with a spin coater (3000 rpm) for 1 minute. And the board | substrate 62 from which the excess part of the hydrolysis liquid was removed was heated at 100 degreeC for 10 minute (s), the binder was made to react, and the board | substrate 62 with which the particle | grain single layer film which consists of colloidal silica particles was formed was acquired.

When the substrate 62 on which the particle monolayer film was formed was obtained in this way, next, the substrate 62 was dry-etched with CHF ₃ gas.

The conditions for this dry etching process were an antenna power of 1500 W, a bias power of 50 to 300 W (13.56 MHz), and a gas flow rate of 50 to 200 sccm.

  When one surface of the substrate 62 after the dry etching process was observed with an AFM, the cross-sectional shape was a truncated cone shape (see FIG. 6B), and the projections were triangular lattices in the planar arrangement. A fine structure arranged in a row was formed (see FIG. 6A).

  Thus, when the center distance p ′ (lattice constant) of the protrusions in the fine structure formed on one surface of the substrate 62 was measured by AFM, the average value of three tests was 226.0 nm. there were.

  Further, the average value of the convex portions of the fine structure in the 25 μm × 5 μm regions randomly selected from the AFM image was calculated, and the average value of each of the 25 locations was further averaged. The average height h of the convex portions in the fine structure was 32.1 nm.

  Furthermore, as a result of calculation using the above-described equation (13), the displacement S of the sequence was 2.6%.

Furthermore, the ratio of the average height h to the average value of the center distance p ′ (average height h / center distance p ′) was 0.142.

  Thereafter, Ag is deposited as a cathode conductive layer 64 to a thickness of 100 nm on one surface of the substrate 62 on which the microstructure is formed, and LiF is deposited as a thickness of 0.8 nm as the electron injection layer 66-5. The film was formed by vapor deposition.

Next, E913 is deposited to a thickness of 40 nm as an electron transport layer 66-4 on the electron injection layer 66-5 by an evaporation method, and then CBP is doped to 8.5% on the electron transport layer 66-4. The light emitting layer 66-3c having a thickness of 15 nm formed by Ir (piq) _3, the light emitting layer 66-3b having a thickness of 3 nm formed by Alq ₃ doped with 1% C545T, and 7% doped with MDP3FL A light emitting layer 66-3a having a thickness of 30 nm formed by ADN was formed by a vapor deposition method.

Furthermore, on the light emitting layer 66-3a, a hole transport layer 66-2 having a thickness of 40 nm formed by T400 and a hole injection layer 66-1 having a thickness of 60 nm formed by MoO _x (x = 1 to 3) are formed. Are sequentially formed by vapor deposition, and an anode conductive layer 68 having a thickness of 100 nm formed by IZO is formed on the hole injection layer 66-1 by sputtering to produce the organic light emitting diode 60. did.

In addition, the light emission area was produced in 2 * 2 mm by using a mask in the case of vapor deposition and sputtering.

  As described above, the organic light emitting diodes 10 and 70 according to the present invention form a two-dimensional lattice structure with a plurality of convex portions 12b on the surface 12a of the substrate 12, and the reflective layer 22 and the anode conductive material are formed on the substrate 12. The cathode conductive layer 18 composed of the layer 14, the organic EL layer 16, the metal layer 18-1 formed in a thin layer so as to transmit visible light, and the transparent conductive layer 18-2 for improving conductivity is sequentially formed. The cathode top emission type is configured such that the light generated in the organic EL layer 16 is extracted from the cathode conductive layer 18 side.

  Further, the organic light emitting diode 50 according to the present invention forms a two-dimensional lattice structure with a plurality of convex portions 52b on the surface 52a of the substrate 52, and on this substrate 52, an anode conductive layer 54, an organic EL layer 56, a cathode conductive layer. 58 is formed by sequentially laminating the light emitted from the organic EL layer 56 from the substrate 52 side.

Furthermore, the organic light emitting diode 60 according to the present invention forms a two-dimensional lattice structure with a plurality of convex portions 62b on the surface 62a of the substrate 62, and on the substrate 62, a cathode conductive layer 64, an organic EL layer 66, an anode conductive layer. The anode top emission type is configured such that light emitted from the organic EL layer 66 is extracted from the anode conductive layer 68 side.

  And in the board | substrate 12 in the organic light emitting diodes 10 and 70, the board | substrate 52 in the organic light emitting diode 50, and the board | substrate 62 in the organic light emitting diode 60, by the etching method using a particle | grain single layer film, each surface is made by several convex part. A two-dimensional lattice structure was prepared. At this time, the particle diameter of the particles forming the particle monolayer film was calculated by the above-described equation (10) because the particle diameter of the particles and the lattice pitch were equal.

  Thereby, in the organic light emitting diodes 10 and 70 according to the present invention, a two-dimensional lattice structure including a plurality of convex portions 12b can be formed on the surface 12a of the substrate 12 in accordance with the surface plasmon mode. By 12b, the two-dimensional lattice structure which consists of a some convex part and a recessed part can be formed in the reflection layer 22 or the metal layer 18-1.

  Further, in the organic light emitting diode 50 according to the present invention, a two-dimensional lattice structure with a plurality of convex portions 52b can be formed on the surface 52a of the substrate 52 in accordance with the surface plasmon mode, and by the plurality of convex portions 52b, A two-dimensional lattice structure including a plurality of convex portions and concave portions can be formed on the cathode conductive layer 58.

  Furthermore, in the organic light emitting diode 60 according to the present invention, a two-dimensional lattice structure with a plurality of convex portions 62b can be formed on the surface 62a of the substrate 62 in accordance with the surface plasmon mode, and with the plurality of convex portions 62b, A two-dimensional lattice structure including a plurality of convex portions and concave portions can be formed on the cathode conductive layer 64.

  Therefore, the organic light emitting diodes 10, 50, 60, and 70 according to the present invention can be manufactured in the same manner as the organic light emitting diode according to the conventional technique.

  Furthermore, in the organic light emitting diodes 10, 50, 60, and 70 according to the present invention, light having a low internal quantum efficiency or a short-life organic light emitting material is emitted from the light extraction surface. Even if it is an organic light-emitting material with low internal quantum efficiency or an organic light-emitting material with a relatively short lifetime, it can improve the light extraction efficiency without reducing the lifetime without applying an excessive applied voltage. Can do.

  By manufacturing an image display device using such organic light emitting diodes 10, 50, 60, and 70, an image display device with high brightness, long life, and power saving can be manufactured.

Furthermore, by producing an illumination device using such organic light emitting diodes 10, 50, 60, and 70, it is possible to produce an illumination device with high brightness, long life, and power saving.

  The embodiment described above may be modified as shown in the following (1) to (7).

  (1) In the above-described embodiment, the metal layer 18-1, the cathode conductive layer 58, and the cathode conductive layer 64 constituting the cathode conductive layer 18 are each made of an alloy containing Al and Ag of 10% or more, Al Alternatively, the alloy is composed of an alloy having an Al content of 10% or more. However, the present invention is not limited to this, and the metal layer 18-1, the cathode conductive layer 58, and the cathode conductive layer 64 are generally used. In particular, a known metal used as a cathode conductive layer of an organic light emitting diode may be used.

  (2) In the above-described embodiment, the organic EL layers 16, 56, and 66 are each composed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. Of course, it is not limited.

  For example, one layer may have the functions of two or more layers among a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

  The light emitting layer is essential, but other layers may be omitted. In this case, as the simplest configuration, the organic EL layer may be composed of only the light emitting layer.

  In the case where the electron injection layer is omitted and the cathode conductive layer has the function of the electron injection layer, the metal used for the cathode conductive layer is replaced with a magnesium alloy such as Mg / Ag = 10/90, for example. That's fine.

  (3) In the above-described embodiment, in the organic light emitting diodes 10 and 70, the particle size of the particles forming the particle monolayer film is determined by focusing on the surface plasmon on the back surface 18-1c of the metal layer 18-1. However, the present invention is not limited to this, and the particle diameter of the particles forming the particle monolayer film is determined by paying attention to the surface 18-1a of the metal layer 18-1 and the surface plasmon in the reflective layer 22. You may do it.

  (4) In the above embodiment, the substrate 12 of the organic light emitting diodes 10 and 70 is formed with the plurality of convex portions 12b periodically and two-dimensionally arranged on the surface 12a. Of course, the present invention is not limited to this, and a plurality of recesses periodically and two-dimensionally arranged on the surface 12a of the substrate 12 may be formed.

In this way, a two-dimensional lattice structure is formed on the surface 12a of the substrate 12 by a plurality of recesses, whereby the reflective layer 22, the anode conductive layer 14, the organic EL layer 16 and the cathode conductive layer 18 are stacked on the substrate 12 In the light emitting diode 10, a two-dimensional structure in which a plurality of concave portions are periodically arranged in a two-dimensional manner on the surface (surface 18-1a) in contact with the transparent conductive layer 18-2 of the metal layer 18-1 forming the cathode conductive layer 18. A lattice structure will be formed. Furthermore, a two-dimensional lattice structure in which a plurality of convex portions are periodically arranged on the surface (back surface 18-1c) in contact with the organic EL layer 16 of the metal layer 18-1 is formed.

  Also, the substrate 52 of the organic light emitting diode 50 is formed with a plurality of convex portions 52b periodically and two-dimensionally arranged on the surface 52a, but it is of course not limited thereto. A plurality of recesses periodically and two-dimensionally arranged may be formed on the surface 52a of the substrate 52.

In the organic light emitting diode 50 manufactured by stacking the anode conductive layer 54, the organic EL layer 56, and the cathode conductive layer 58 on the substrate 52 by forming a two-dimensional lattice structure on the surface 52 a of the substrate 52 in this manner. A plurality of convex portions are formed on the surface (back surface 58c) of the cathode conductive layer 58 in contact with the organic EL layer 56.

  Further, the substrate 62 of the organic light emitting diode 60 is formed with a plurality of convex portions 62b periodically and two-dimensionally arranged on the surface 62a. However, the present invention is not limited to this. A plurality of recesses periodically and two-dimensionally arranged on the surface 62a of the substrate 62 may be formed.

In the organic light emitting diode 60 manufactured by stacking the cathode conductive layer 64, the organic EL layer 66, and the anode conductive layer 68 on the substrate 62 by forming a two-dimensional lattice structure on the surface 62 a of the substrate 62 in this manner. A plurality of recesses are formed on the surface (surface 64 a) of the cathode conductive layer 64 in contact with the organic EL layer 66.

  Specifically, as a method for producing a concave microstructure on a substrate, a method of producing an inversion type on a resin layer applied on the substrate using a nanoimprint method can be used.

  In addition, after depositing a metal such as Cr or Ni on a particle mask (a particle monolayer film made of particles having a particle diameter calculated by the above formula) formed on a substrate, the particles are deposited. A method for producing a concave structure in a place where there is no metal by dry etching the substrate using a metal vapor deposition layer (having a mesh structure with holes in the place where particles were present) removed and remaining on the substrate as a mask Etc. are available.

  In addition, by using a substrate having a structure in which a plurality of recesses are periodically and two-dimensionally arranged on the surface thus formed as a mold, and transferring the structure of the mold surface to a substrate original plate, a plurality of surfaces are formed on the surface of each substrate. You may make it produce the two-dimensional lattice structure by a recessed part.

  (5) In the above-described embodiment, in each of the layers sequentially stacked on the substrate, a structure equivalent to the two-dimensional lattice structure formed by the plurality of convex portions 12b formed on the surface 12a of the substrate 12 is formed. However, it is needless to say that the present invention is not limited to this, and a two-dimensional lattice structure may be formed only on the layer formed of the metal material, or the surface of the layer formed of the metal material or A two-dimensional lattice structure may be formed only on one surface of the back surface.

  That is, in the organic light emitting diodes 10 and 70, the reflective layer 22 (that is, the upper surface and the lower surface of the reflective layer 22) and the metal layer 18-1 (that is, the upper surface and the lower surface of the metal layer 18-1). A two-dimensional lattice structure may be formed only on the two-dimensional lattice structure, or a two-dimensional lattice structure may be formed only on either the reflective layer 22 or the metal layer 18-1. Furthermore, the surface of the reflective layer 22 (that is, the upper surface of the reflective layer 22 and the surface on which the organic EL layer 16 is located) or the back surface (that is, the lower surface of the reflective layer and the surface on which the substrate 12 is located). )), Or the surface 18-1a of the metal layer 18-1 (that is, the upper surface of the metal layer 18-1) or the back surface 18-1c (that is, the lower surface of the metal layer 18-1). The two-dimensional lattice structure may be formed only on one of the surfaces.

  In the organic light emitting diode 50, a two-dimensional lattice structure may be formed only on the cathode conductive layer 58 (that is, the upper surface and the lower surface of the cathode conductive layer 58). A two-dimensional lattice structure may be formed only on one surface of 58a (that is, the upper surface of the cathode conductive layer 58) or the back surface 58c (that is, the lower surface of the cathode conductive layer 58). .

  Further, in the organic light emitting diode 60, a two-dimensional lattice structure may be formed only on the cathode conductive layer 64 (that is, the upper surface and the lower surface of the cathode conductive layer 64), or the surface of the cathode conductive layer 64 may be formed. A two-dimensional lattice structure may be formed only on one surface of 64a (that is, the upper surface of the cathode conductive layer 64) or the back surface 64c (that is, the lower surface of the cathode conductive layer 64). .

  (6) In the above-described embodiment, three organic light emitting materials that emit light of different wavelengths are stacked to form a light emitting layer, and white light is emitted from the light emitting layer. Of course, the light emitting layer may be formed by laminating two organic light emitting materials that emit light of different wavelengths, and white light may be emitted from the light emitting layer.

  (7) You may make it combine suitably the embodiment shown above and the modification shown in said (1)-(6).

  “Example 1” is the organic light-emitting diode according to the first embodiment having the characteristics of the energy dissipation diagram of FIG. 4 manufactured by the method described above, and “Comparative Example 1” is a layer adjacent to each layer. Except that the surface in contact with the surface is flat (that is, a two-dimensional lattice structure is not formed by a plurality of convex portions or a plurality of concave portions on the surface). It is an organic light emitting diode produced by a layer structure.

Specifically, “Example 1” and “Comparative Example 1” include a substrate 12 made of quartz glass, a reflective layer 22 made of Al having a thickness of 100 nm, and a thickness made of IZO. 20% anode conductive layer 14, 80 nm thick hole injection layer 16-1 formed by HAT-CN, 70 nm thick hole transport layer 16-2 formed by T400, and 7% MDP3FL doped A light emitting layer 16-3a having a thickness of 40 nm formed by ADN, a light emitting layer 16-3b having a thickness of 10 nm formed by Alq ₃ doped with 1% C545T, and Ir (piq) doped with 8.5% CBT. ) emitting layer 16-3c thick 20nm formed by _3, the electron transport layer 16-4 having a thickness of 50nm formed by E913, thickness formed by Al A metal layer 18-1 10 nm, and to be composed of a transparent conductive layer 18-2 having a thickness of 110nm formed by IZO.

In “Example 1”, the extraction wavelength λ (that is, the peak wavelength value λ _{1 of the} emission spectrum to be enhanced because the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials) is set to 630 nm. The average value of the center-to-center distances P of the plurality of convex portions formed on the surface 12a of the substrate 12 was 573.7 nm.

  In addition, “Example 2” is the organic light-emitting diode according to the second embodiment having the characteristics of the energy dissipation diagram of FIG. 5 manufactured by the method described above, and “Comparative Example 2” is adjacent to each layer. “Example 2” except that the surface in contact with the mating layer is flat (that is, a two-dimensional lattice structure is not formed by a plurality of convex portions or a plurality of concave portions on the surface). It is an organic light emitting diode produced by the same layer structure.

Specifically, as “Example 2” and “Comparative Example 2”, a substrate 12 made of quartz glass, a reflective layer 22 made of Al having a thickness of 100 nm, and a thickness made of IZO are used. 20% anode conductive layer 14, 40 nm thick hole injection layer 16-1 formed by HAT-CN, 50 nm thick hole transport layer 16-2 formed by T400, and 7% MDP3FL doped Light emitting layer 16-3a with a thickness of 20 nm formed by ADN, light emitting layer 16-3b with a thickness of 2 nm formed by Alq ₃ doped with 1% C545T, and Ir (piq) doped with 8.5% CBT ) emitting layer 16-3c thick 10nm formed by _3, the electron transport layer 16-4 having a thickness of 30nm formed by E913, thickness formed by Al of A metal layer 18-1 0 nm, and to be composed of a transparent conductive layer 18-2 having a thickness of 110nm formed by IZO.

In “Example 2”, the extraction wavelength λ (that is, the peak wavelength value λ _{1 of the} emission spectrum to be enhanced because the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials) is 470 nm, The average value of the center-to-center distances P of the plurality of convex portions formed on the surface 12a of the substrate 12 was set to 307.6 nm.

  Furthermore, “Example 3” is the organic light-emitting diode of the third embodiment having the characteristics of the energy dissipation diagram of FIG. 8 manufactured by the method described above, and “Comparative Example 3” is adjacent to each layer. “Example 3” except that the surface in contact with the mating layer is flat (that is, a two-dimensional lattice structure is not formed by a plurality of convex portions or a plurality of concave portions on the surface). It is an organic light emitting diode produced by the same layer structure.

Specifically, “Example 3” and “Comparative Example 3” are formed of a substrate 52 made of quartz glass, an anode conductive layer 54 having a thickness of 100 nm made of IZO, and HAT-CN. A 30 nm thick hole injection layer 56-1; a 50 nm thick hole transport layer 56-2 formed by T400; and a 10 nm thick light emitting layer 56-3a formed by ADN doped with 7% of MDP3FL. A 2 nm thick light emitting layer 56-3b formed of Alq ₃ doped with 1% C545T and a 10 nm thick light emitting layer 56- formed of Ir (piq) ₃ doped with 8.5% CBP. 3c, an electron transport layer 56-4 with a thickness of 30 nm formed by E913, an electron injection layer 56-5 with a thickness of 0.8 nm formed by LiF, and Al. It was to be constructed by the cathode conductive layer 58 having a thickness of 150nm which is.

In “Example 3”, the extraction wavelength λ (that is, the peak wavelength value λ _{1 of the} emission spectrum to be enhanced because the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials) is set to 630 nm. The average value of the center-to-center distances P of the plurality of convex portions formed on the surface 52a of the substrate 52 was 413.4 nm.

  Furthermore, “Example 4” is the organic light-emitting diode of the fourth embodiment having the characteristics of the energy dissipation diagram of FIG. 11 manufactured by the method described above, and “Comparative Example 4” “Example 4” except that a surface in contact with an adjacent layer is flat (that is, a two-dimensional lattice structure is not formed by a plurality of convex portions or a plurality of concave portions on the surface). It is the organic light emitting diode produced by the same layer structure.

Specifically, as [Example 4] and [Comparative Example 4], a substrate 62 formed of quartz glass, a cathode conductive layer 64 of 100 nm thickness formed of Ag, and a thickness formed of LiF. 0.8 nm thick electron injection layer 66-5, 40 nm thick electron transport layer 66-4 formed by E913, and 15 nm thick formed by Ir (piq) ₃ doped with 8.5% CBP. Light emitting layer 66-3c, 3 nm thick light emitting layer 66-3b formed of Alq ₃ doped with 1% C545T, and 30 nm thick light emitting layer 66- formed of ADN 7% doped with MDP3FL 3a, a hole transport layer 66-2 having a thickness of 40 nm formed by T400, a hole injection layer 66-1 having a thickness of 60 nm formed by MoO _x (x = 1 to 3), and IZ The anode conductive layer 68 is formed of O and has a thickness of 100 nm.

In “Example 4”, the extraction wavelength λ (that is, the peak wavelength value λ _{1 of the} emission spectrum to be enhanced because the internal quantum efficiency and the lifetime of the organic light emitting material are inferior to those of other organic light emitting materials) is 470 nm, The average value of the center-to-center distances P of the plurality of convex portions formed on the surface 62a of the substrate 62 was 226.0 nm.

As “Example 1”, “Example 2”, “Example 3”, “Example 4”, “Comparative Example 1”, “Comparative Example 2”, “Comparative Example 3”, and “Comparative Example 4” The produced organic light emitting diode was measured for current efficiency (cd / A) and power efficiency (lm / W) at a unit current of 14.8 mA / cm ² .

  As a result, as shown in FIG. 10, the organic light emitting diode manufactured as “Example 1” has a current efficiency improvement rate of 1.65 times that of the organic light emitting diode manufactured as “Comparative Example 1”. In addition, it showed a 1.72 times improvement rate in power efficiency, indicating that the luminous efficiency was dramatically improved.

  In addition, the organic light emitting diode manufactured as “Example 2” shows 1.47 times improvement in current efficiency and 1.1 in power efficiency as compared with the organic light emitting diode manufactured as “Comparative Example 2”. The rate of improvement was 68 times, indicating that the luminous efficiency was dramatically improved.

  In addition, the organic light emitting diode manufactured as “Example 3” has a current efficiency of 2.11 times higher than the organic light emitting diode manufactured as “Comparative Example 3” and also has a power efficiency of 2.37. The rate of improvement was doubled, indicating that the luminous efficiency was dramatically improved.

  Further, the organic light emitting diode manufactured as “Example 4” shows a 1.88 times improvement in current efficiency and 2.12 in power efficiency as compared with the organic light emitting diode manufactured as “Comparative Example 4”. The rate of improvement was doubled, indicating that the luminous efficiency was dramatically improved.

  The present invention is suitable for use as an organic light emitting diode used in an image display device, a lighting device, or the like.

10, 50, 60 Organic light emitting diode 12, 52, 62 Substrate 14, 54, 68 Anode conductive layer 16, 56, 66 Organic EL layer 16-1, 56-1, 66-1 Hole injection layer 16-2, 56- 2, 66-2 Hole transport layer 16-3, 56-3, 66-3 Light emitting layer 16-3a, 16-3b, 16-3c, 56-3a, 56-3b, 56-3c, 66-3a, 66 -3b, 66-3c Organic light emitting material 16-4, 56-4, 66-4 Electron transport layer 16-5, 56-5, 66-5 Electron injection layer 18, 58, 64 Cathode conductive layer 18-1 Metal layer 18-2 Transparent conductive layer 20 Power source 22 Reflective layer

Claims (8)

At least a first conductive layer made of a metal material and made of a transparent conductive layer made of a transparent conductive material made of a metal layer capable of transmitting light, or made of only a metal layer made of a metal material, and a second made of a transparent conductive material An organic EL layer including a plurality of light-emitting layers containing organic light-emitting materials that emit light of different wavelengths, and the first conductive layer, the second conductive layer, and the organic EL layer, In the organic light emitting diode that is laminated in a predetermined order on the organic light emitting diode substrate so that the organic EL layer is positioned between the first conductive layer and the second conductive layer,
Forming a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged two-dimensionally on a predetermined surface of the metal layer of the first conductive layer on which adjacent layers are formed;
Among the plurality of organic light emitting material, the internal quantum efficiency and an organic light emitting material wherein the metal layer at least one of the life time is corresponding to the peak wavelength lambda ₁ of the emission spectrum of a given organic luminescent material inferior other organic luminescent materials When the real part of the propagation constant of surface plasmon generated on the predetermined surface is k ₁ , the distance P between adjacent convex portions or concave portions formed on the predetermined surface is expressed by the following equation (1). a value in the range of the (1) P ₀ in the expression, when forming a triangular lattice structure as the two-dimensional lattice structure (2) was filled, to form a square lattice structure as the two-dimensional lattice structure When the organic light emitting diode satisfies the expression (3).
The organic light emitting diode according to claim 1,
The metal material forming the metal layer in the first conductive layer is Ag, Al, an alloy having an Ag content of 10% by mass or more, or an alloy having an Al content of 10% by mass or more. Organic light emitting diode. The organic light emitting diode according to any one of claims 1 and 2,
The depth of the said recessed part and the height of the said convex part are 15-180 nm. The organic light emitting diode characterized by the above-mentioned. An organic light emitting diode substrate manufacturing method for manufacturing an organic light emitting diode substrate used in the organic light emitting diode according to any one of claims 1, 2, or 3,
A plurality of layers on the surface on which the first conductive layer, the second conductive layer, and the organic EL layer are stacked by a dry etching method using a single-layer particle film in which predetermined particles are closely packed in two dimensions as an etching mask. A method of manufacturing a substrate for an organic light emitting diode, comprising forming a two-dimensional lattice structure in which convex portions or concave portions are periodically arranged in two dimensions. An organic light emitting diode substrate manufacturing method for manufacturing an organic light emitting diode substrate used in the organic light emitting diode according to any one of claims 1, 2, or 3,
A mold in which a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in two dimensions is formed by a dry etching method using a particle monolayer film in which predetermined particles are closely packed in two dimensions as an etching mask. Made,
A two-dimensional lattice structure in which a plurality of convex portions or concave portions formed in the mold are periodically arranged in two dimensions is transferred, and the first conductive layer, the second conductive layer, and the organic EL layer are stacked. A method for producing a substrate for an organic light emitting diode, comprising: forming a two-dimensional lattice structure in which a plurality of convex portions or concave portions are periodically arranged in a two-dimensional manner on a surface to be formed. In the manufacturing method of the board | substrate for organic light emitting diodes of Claim 5,
The method of manufacturing a substrate for an organic light emitting diode, wherein the predetermined particle diameter D satisfies the formula (4).
D = P (4)   An image display apparatus provided with the organic light emitting diode of any one of Claims 1, 2, or 3.   An illuminating device provided with the organic light emitting diode of any one of Claims 1, 2, or 3.