JP2017022008A - Organic el element and manufacturing method for the same - Google Patents

Abstract

An object of the present invention is to improve light extraction efficiency and reliability. Kind Code: A1 An organic EL element (1) includes a translucent substrate (10), a light control layer (20) provided on the substrate (10), and a light emitting laminate (30) provided on the light control layer (20). The layer 20 includes a first layer 21 and a second layer 22 having a refractive index different from that of the first layer 21 and provided on the first layer 21 . At least one has unevenness 23 for diffusing the light emitted by the light-emitting laminate 30 , and the first taper angle formed by the end surface of the first layer 21 with respect to the substrate 10 is such that the end surface of the second layer 22 is formed with respect to the substrate 10 . different from the second taper angle. [Selection drawing] Fig. 1

Description

  The present invention relates to an organic EL (Electro Luminescence) element and a manufacturing method thereof.

  Conventionally, development of various optical devices such as a lighting device and a display device including an organic EL element has been advanced. In a general organic EL element, an anode, a light emitting layer, and a cathode are laminated on a substrate. Organic EL elements are required to have characteristics such as long life, high efficiency, and high luminance.

  Patent Document 1 discloses an organic EL element in which a concavo-convex portion and a planarization insulating film for flattening the concavo-convex portion are provided on a surface on the electrode side of a substrate. Since the refractive index of the planarization insulating film is adjusted to be larger than the refractive index of the substrate, the occurrence of total reflection at the interface (uneven portion) between the substrate and the planarization insulating film is suppressed, and the light extraction efficiency is increased. It has been.

  Patent Document 2 discloses an organic EL element including a light emitting layer formed on a concavo-convex structure. Due to the concavo-convex structure, the area of the light emitting portion is larger than the area of the opening from which light is extracted, so that high light extraction efficiency is realized.

JP 2006-294491 A JP 2003-257661 A

  However, in the organic EL element described in Patent Document 1, since light is scattered in the planarization insulating film, light leakage from the end face of the insulating film occurs, and the light extraction efficiency is not sufficient. Similarly, in the organic EL element described in Patent Document 2, light leakage from the end face occurs, so that the light extraction efficiency is not sufficient. Furthermore, since the electrodes are bent due to the concavo-convex structure, there is a problem that short-circuiting between the electrodes is likely to occur and reliability is low.

  Then, an object of this invention is to provide the organic EL element which can improve light extraction efficiency and reliability, and its manufacturing method.

  In order to achieve the above object, an organic EL element according to one embodiment of the present invention includes a light-transmitting substrate, a light control layer that is provided over the substrate and has a light diffusion structure that diffuses light, and the light. A light emitting laminate provided on the control layer, wherein the light control layer has a refractive index different from that of the first layer and the second layer provided on the first layer. The first taper angle formed by the end surface of the first layer with respect to the substrate is different from the second taper angle formed by the end surface of the second layer with respect to the substrate.

  The method for manufacturing an organic EL element according to one embodiment of the present invention includes a step of forming a light control film having a light diffusion structure for diffusing light on a substrate, and a step of removing a part of the light control film. And forming a light emitting laminate on the light control film. In the step of forming the light control film, a first film is formed on the substrate, and the first film is formed on the first film. A second film having a refractive index different from that of the film is formed, and in the removing step, a part of the first film and the second film is removed by irradiating with laser light.

  According to the organic EL element and the like according to the present invention, light extraction efficiency and reliability can be improved.

It is a schematic sectional drawing of the organic EL element which concerns on embodiment of this invention. It is an expanded sectional view of the edge part vicinity of the light control layer of the organic EL element which concerns on embodiment of this invention. It is a flowchart which shows the manufacturing method of the organic EL element which concerns on embodiment of this invention. It is a schematic diagram which shows the formation process of the light control layer in the manufacturing method of the organic EL element which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the relationship between the numerical aperture of a lens and the beam shape of the laser apparatus which concerns on embodiment of this invention. It is a cross-sectional SEM image of the edge part vicinity of the light control layer which concerns on embodiment of this invention.

  Below, the organic EL element and its manufacturing method which concern on embodiment of this invention are demonstrated in detail using drawing. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member. In the following embodiments, expressions such as substantially uniform are used. For example, substantially uniform means not only completely uniform, but also substantially uniform, that is, includes an error of, for example, several percent. The same applies to expressions using other “abbreviations”.

  Further, in this specification, the terms “upper” and “lower” do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute space recognition, but are based on the stacking order in the stacking configuration. Is used as a term defined by the relative positional relationship. The terms “upper” and “lower” are not only used when two components are spaced apart from each other, and there is another component between the two components. The present invention is also applied when two components are in close contact with each other and are in contact with each other.

(Embodiment)
[Organic EL device]
First, an outline of the organic EL element according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of an organic EL element 1 according to this embodiment.

  As shown in FIG. 1, the organic EL element 1 includes a substrate 10, a light control layer 20, a light emitting laminate 30, a sealing substrate 40, and an adhesive layer 50. The organic EL element 1 according to the present embodiment is a bottom emission type light emitting element in which light is emitted from the substrate 10. Specifically, the light emitted from the light emitting laminate 30 is emitted from the substrate 10 through the light control layer 20.

  Below, each component with which the organic EL element 1 is provided is demonstrated in detail.

[substrate]
The substrate 10 is a translucent substrate. For example, the substrate 10 is a transparent substrate that transmits at least part of visible light. Specifically, the substrate 10 is a glass substrate such as soda glass, non-alkali glass, non-fluorescent glass, phosphate glass, or borate glass. Alternatively, the substrate 10 may be a quartz substrate or a resin substrate. In the present embodiment, as an example, the substrate 10 is a glass substrate having a refractive index of 1.5.

  The substrate 10 may contain particles, powder, bubbles or the like having a refractive index different from that of the substrate base material, or has a light diffusion effect by providing a predetermined shape such as irregularities on the substrate surface. Also good. The substrate 10 is made of a material having high moisture resistance, for example. Thereby, the board | substrate 10 can suppress that a water | moisture content permeates the inside of an element.

[Light control layer]
The light control layer 20 is provided on the substrate 10. The light control layer 20 is provided to effectively emit light emitted from the light emitting laminate 30 from the substrate 10. That is, the organic EL element 1 can increase the light extraction efficiency from the substrate 10 by including the light control layer 20.

  In the present embodiment, the light control layer 20 is a light-transmitting laminated body in which a plurality of layers of at least two or more layers are laminated. The light control layer 20 has a light diffusion structure that diffuses light.

  By providing the light diffusion structure, total reflection occurring between the light control layer 20 and the substrate 10 can be suppressed. Moreover, since light is diffused (scattered), a difference (color difference) between the color when the organic EL element 1 is viewed from a direction perpendicular to the substrate 10 and the color when viewed from an oblique direction can be suppressed. . That is, the viewing angle dependency can be suppressed and light can be emitted with a low color difference.

  As shown in FIG. 1, the light control layer 20 includes a first layer 21 and a second layer 22. Each of the first layer 21 and the second layer 22 has translucency. In the present embodiment, irregularities 23 are formed at the interface between the first layer 21 and the second layer 22. Further, diffusion particles are dispersed in each of the first layer 21 and the second layer 22. In the present embodiment, the unevenness 23 and the diffusion particles correspond to a light diffusion structure. That is, in the present embodiment, the light diffusion structure is realized by the shape or material of at least one of the first layer 21 and the second layer 22.

  The first layer 21 is provided on the substrate 10. The first layer 21 is translucent and has irregularities 23 on the upper surface. The irregularities 23 are provided on substantially the entire upper surface of the first layer 21. For example, the film thickness of the first layer 21 is about 4 μm, and the height of the unevenness 23 is about 1 μm.

  In the present embodiment, diffusion particles (light diffusing agent) are dispersed in the first layer 21. That is, the first layer 21 has a light diffusion structure by including not only the unevenness 23 but also the diffusion particles.

  For example, the first layer 21 has an acrylic or epoxy resin material as a base material, and fillers are dispersed in the layer as diffusion particles. Examples of the filler include silica and glass. The refractive index of the first layer 21 is, for example, 1.3 to 1.5.

The first layer 21 is not limited to a resin material (organic material) and may be formed from an inorganic material. For example, the first layer 21 has a silicon nitride film (SiN, refractive index of about 1.9) as a base material, and titanium oxide (TiO ₂ , refractive index of about 2.1) particles are dispersed in the layer as diffusion particles. Has been. The film thickness and material of the first layer 21 are not particularly limited to these examples.

  The first layer 21 is formed by, for example, coating, and the unevenness 23 is formed on the upper surface by an imprint method such as nanoimprint. The shape, width (pitch), height, and the like of the unevenness 23 are not particularly limited as long as the light emitted from the light emitting laminate 30 can be scattered. For example, the unevenness 23 may form a light diffraction structure. Specifically, the concave and convex portion 23 may be formed with a concave portion and a convex portion at a predetermined cycle.

  Thereby, by utilizing the diffraction of light, it is possible to extract light having a total reflection angle or more, so that the light extraction efficiency can be increased. In the present embodiment, since the filler is dispersed in the first layer 21, light is further scattered by the filler. For this reason, the viewing angle dependency by diffraction can be suppressed.

  The second layer 22 is provided on the first layer 21. The second layer 22 is a flattening layer that has translucency and flattens the unevenness 23 provided on the upper surface of the first layer 21. Specifically, irregularities 23 are formed on the lower surface of the second layer 22, and the upper surface is a flat surface. That is, the second layer 22 is provided in contact with the first layer 21 so as to fill the unevenness 23. For example, the film thickness of the second layer 22 is about 2 μm.

  The second layer 22 has a refractive index different from that of the first layer 21. In the present embodiment, the refractive index of the second layer 22 is smaller than the refractive index of the first layer 21, but is not limited to this. The refractive index of the second layer 22 may be larger than the refractive index of the first layer 21.

  In the present embodiment, diffusion particles are dispersed in the second layer 22. That is, the second layer 22 has a light diffusion structure by including not only the unevenness 23 but also the diffusion particles.

For example, the second layer 22 has nanoparticles dispersed in the layer as diffusion particles using an acrylic or epoxy resin material as a base material. Examples of the nanoparticles include titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ). The refractive index of the second layer 22 is, for example, 1.8.

[Light emitting laminate]
The light emitting laminate 30 is provided on the light control layer 20. In the present embodiment, as shown in FIG. 1, the light emitting laminate 30 is disposed in a sealed space 70 sealed by a substrate 10 and a sealing substrate 40. The light emitting laminate 30 includes a first electrode 31, an organic layer 32, and a second electrode 33.

  The 1st electrode 31 is one of a pair of electrodes with which the light emitting laminated body 30 is provided, for example, is an anode. The first electrode 31 is an electrode for injecting holes into the organic layer 32. Further, the first electrode 31 is an electrode on the light extraction side and has translucency.

  The material of the first electrode 31 is an electrode material having translucency, and for example, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function can be used. For example, as the material of the first electrode 31, a material having a work function of 4 eV or more and 6 eV or less can be used so that the difference from the HOMO (High Occupied Molecular Orbital) level does not become too large. Specifically, the material of the first electrode 31 includes conductive oxides such as ITO (Indium Tin Oxide), tin oxide, zinc oxide, IZO (Indium Zinc Oxide), copper iodide, and conductive materials such as PEDOT and polyaniline. A functional polymer, a carbon nanotube, or the like can be used.

  The first electrode 31 is formed as a thin film by, for example, a sputtering method, a vacuum evaporation method, a coating method, or the like. An auxiliary wiring may be provided on the first electrode 31. The auxiliary wiring is, for example, a grid-shaped wiring, and is formed of a metal material having an electric resistance smaller than that of the material forming the first electrode 31. Thereby, even if the first electrode 31 is thinned, the voltage drop in the surface is suppressed, so that the light transmittance can be increased while suppressing the variation in luminance in the surface.

  As shown in FIG. 1, a terminal portion 31 a is provided at the end of the first electrode 31. The terminal portion 31a is exposed to the outside of the sealing substrate 40, and receives power from the outside for causing the light emitting laminate 30 to emit light. Specifically, the terminal portion 31 a is a part of the first electrode 31, and is a portion where the first electrode 31 extends to the end of the substrate 10.

  Although not shown, a part of the second electrode 33 is similarly extended to be exposed to the outside of the sealing substrate 40 to form a terminal portion. An external power supply (not shown) applies power between the first electrode 31 and the second electrode 33 by supplying power between a terminal portion that is a part of the second electrode 33 and the terminal portion 31 a.

  The organic layer 32 includes one or more light emitting layers that are provided between the first electrode 31 and the second electrode 33 and emit light according to a voltage applied between the first electrode 31 and the second electrode 33. . Specifically, the organic layer 32 is provided on the first electrode 31.

  The organic layer 32 includes, for example, a plurality of organic layers including one or more light emitting layers. Specifically, the organic layer 32 includes a hole injection layer, a hole transport layer, a light emitting layer (organic EL layer), an electron transport layer, and an electron injection layer. Each layer constituting the organic layer 32 is formed by vapor deposition, spin coating, casting, or the like.

  The organic layer 32 includes, for example, a plurality of light emitting layers that emit light having different wavelengths. For example, the organic layer 32 emits white light by including three color light-emitting layers of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. For example, the organic layer 32 may have a laminated structure of a blue hole transporting light emitting layer, a green electron transporting light emitting layer, and a red electron transporting light emitting layer, or a blue electron transporting light emitting layer and a green electron. You may have a laminated structure of a transportable light emitting layer and a red electron transporting light emitting layer.

  In addition, the light emitting layer included in the organic layer 32 may be a single layer. For example, when the luminescent color is white, the light emitting layer is formed by doping with red, green and blue dopant dyes.

  In addition, the structure of a light emitting layer is not specifically limited, A luminescent color is not limited to white. That is, the light emitting laminate 30 according to the present embodiment may emit colored light such as red. A light emitting layer is formed from organic materials, such as a diamine, anthracene, and a metal complex, for example.

  The 2nd electrode 33 is the other of a pair of electrodes with which the light emitting laminated body 30 is provided, for example, is a cathode. The second electrode 33 is an electrode for injecting electrons into the organic layer 32. The second electrode 33 is a light reflection side electrode and has light reflectivity.

  As the material of the second electrode 33, a material having light reflectivity, for example, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a small work function can be used. For example, as the material of the second electrode 33, a material having a work function of 1.9 eV or more and 5 eV or less can be used so that the difference from the LUMO (Lowest Unoccupied Molecular Orbital) level does not become too large. Specifically, as the material of the second electrode 33, aluminum, silver, magnesium, or an alloy of these and other metals can be used.

  The second electrode 33 is formed as a thin film by, for example, a sputtering method, a vacuum evaporation method, a coating method, or the like.

  In the present embodiment, an example in which the first electrode 31 is an anode and the second electrode 33 is a cathode is shown, but the present invention is not limited to this. The first electrode 31 may be a cathode and the second electrode 33 may be an anode.

[Sealing substrate]
The sealing substrate 40 is provided on the light emitting laminate 30 side of the substrate 10 so as to cover the light emitting laminate 30. Specifically, the sealing substrate 40 seals the light emitting laminate 30 by adhering to the substrate 10 with the adhesive layer 50 so as to cover the light emitting laminate 30. Thereby, deterioration of the light emitting laminated body 30 can be suppressed by suppressing physical impact and suppressing intrusion of moisture.

  For example, the sealing substrate 40 is formed of a material having a low moisture permeability. The sealing substrate 40 is a glass substrate, for example. As shown in FIG. 1, the sealing substrate 40 is a so-called cap-shaped sealing substrate provided with a storage recess for storing the light emitting laminate 30. Thereby, the light emitting laminated body 30 can be sealed with sufficient airtightness.

  The substrate 10 and the sealing substrate 40 are bonded to each other at atmospheric pressure or in a state where the pressure is sufficiently reduced (vacuum). Therefore, the sealed space 70 is filled with a predetermined gas having an atmospheric pressure or less. The gas is, for example, a rare gas such as argon, nitrogen, dry air, or the like. The sealed space 70 may be filled with a predetermined filler instead of gas.

[Adhesive layer and parts to be removed]
The adhesive layer 50 is formed from a resin adhesive that bonds the substrate 10 and the sealing substrate 40 together. Specifically, the adhesive layer 50 is formed by curing an adhesive mainly composed of a thermosetting resin or an ultraviolet curable resin. The adhesive layer 50 may contain a desiccant. Thereby, the infiltration of moisture through the adhesive layer 50 can be further suppressed.

  In the present embodiment, the adhesive layer 50 is provided on the portion to be removed 60. The removed portion 60 is a portion where the light control layer 20 on the substrate 10 is not provided, and is a portion removed after the material of the light control layer 20 is formed on the entire surface.

  The removed portion 60 is formed along the outer periphery of the substrate 10, and the adhesive layer 50 is formed so as to surround the outer periphery of the light emitting laminate 30. Specifically, the portion to be removed 60 is formed in a frame shape over the entire outer periphery of the substrate 10, and the adhesive layer 50 is also formed over the entire periphery of the end portion of the substrate 10. In the portion where the first electrode 31 and the second electrode 33 are not extended, the adhesive layer 50 directly bonds the substrate 10 and the sealing substrate 40, and the first electrode 31 or the second electrode 33 is extended. The extending portion and the sealing substrate 40 are bonded to each other at the existing portion.

[Refractive index and taper angle]
FIG. 2 is an enlarged cross-sectional view of the vicinity of the end of the light control layer 20 of the organic EL element 1 according to the present embodiment. Specifically, FIG. 2 shows a region II surrounded by a broken line in FIG.

  As will be described in detail later, when the light control film formed on the substrate 10 is irradiated with laser light, a part of the light control film is removed and the removed portion 60 is formed. The end surface of the light control layer 20 is processed into a predetermined shape. Specifically, a taper (inclination) corresponding to the refractive index is formed on the end surface. That is, the end surface 21a of the first layer 21 and the end surface 22a of the second layer 22 are formed by laser processing.

As shown in FIG. 2, the refractive index of the first layer 21 is n ₁ , and the first taper angle that is the angle formed by the end surface 21 a of the first layer 21 with respect to the substrate 10 is θ ₁ . Similarly, the refractive index of the second layer 22 is n ₂ , and the second taper angle that is the angle formed by the end face 22 a of the second layer 22 with respect to the substrate 10 is θ ₂ .

At this time, in this embodiment, (Expression 1) satisfies cos θ ₁ > 1 / n ₁ and (Expression 2) satisfies cos θ ₂ > 1 / n ₂ . In addition, it is not necessary to satisfy | fill both (Formula 1) and (Formula 2), You may satisfy | fill only one. Even in this case, the light extraction efficiency can be increased.

  By satisfying (Expression 1), the parallel light 81 that is the light propagating in the first layer 21 in parallel with the substrate 10 is totally reflected by the end face 21a. When the end surface 21a of the first layer 21 is not tapered (that is, the end surface 21a is vertical), the light most easily emitted from the end surface 21a is parallel light 81. In addition, it is considered that most of the light that propagates in the first layer 21 and reaches the end surface 21 a is substantially parallel light because the total reflection is repeated on the upper surface and the lower surface of the first layer 21. Therefore, the light extraction efficiency can be increased by totally reflecting the parallel light 81.

Total reflection, the incident angle of the parallel light 81 to the end face 21a is produced is larger than the critical angle theta _c. The incident angle of the parallel light 81 is represented by 90 ° -θ _1. The critical angle θ _c is defined as sin θ _c = n ₀ / n ₁ when the end face 21 a is exposed in the portion to be removed 60 (specifically, dry air (refractive index n ₀ is approximately 1)). Is done.

  Therefore, (Equation 1) is derived from the following (Equation 3) from “incident angle> critical angle” which is the total reflection condition.

(Formula 3) 90 ° −θ ₁ > θ _c
⇒sin (90 ° −θ ₁ )> sin θ _c = n ₀ / n ₁ = 1 / n ₁
⇒ cos θ ₁ > 1 / n ₁ (Formula 1)

The smaller the refractive index n ₁ of the first layer 21, that is, the smaller the difference in refractive index between the first layer 21 and the part to be removed 60 (air), the smaller the limit value of the taper angle θ ₁ . Therefore, as the refractive index n ₁ of the first layer 21 is smaller, the inclination of the end surface 21a becomes gentler.

Conversely, the greater the refractive index n ₁ of the first layer 21, that is, the greater the difference in refractive index between the first layer 21 and the portion to be removed 60 (air), the greater the limit value of the taper angle θ ₁ . Thus, as the refractive index n ₁ of the first layer 21 is small, the inclination of the end face 21a may be steep. The limit value of the taper angle θ ₁ is θ ₁ when an equal sign is established between the left side and the right side of (Expression 1). For example, when the refractive index n ₁ of the first layer 21 is 2, the limit value of the taper angle θ ₁ is 60 °. That is, in this case, the taper angle θ ₁ only needs to be smaller than 60 °.

  The same as described above holds true for the second layer 22. Therefore, by satisfying (Equation 2), the parallel light 82 is totally reflected by the end face 22 a of the second layer 22. Thereby, the light extraction efficiency can be further increased.

[Production method]
Then, the manufacturing method of the organic EL element 1 which concerns on this Embodiment is demonstrated using FIG.3 and FIG.4. FIG. 3 is a flowchart showing a method for manufacturing the organic EL element 1 according to this embodiment. FIG. 4 is a schematic diagram illustrating a process of forming the light control layer 20 in the method for manufacturing the organic EL element 1 according to the present embodiment.

  As shown in FIG. 3, in the method for manufacturing the organic EL element 1 according to the present embodiment, first, the light control film 120 is formed on the substrate 10 (S10). Next, a part of the light control film 120 is removed by irradiating laser light (S20). Next, the light emitting laminate 30 is formed on the light control film 120 (S30).

  Hereinafter, details of the formation process of the light control layer 20, that is, the formation process (S10) of the light control film 120 and the removal process (S20) of a part of the light control film 120 will be described with reference to FIG. To do.

  First, as shown in FIG. 4A, a substrate 10 is prepared.

  Next, as shown in FIG. 4B, a first film 121 is formed on the substrate 10. Specifically, after applying an acrylic resin material containing a filler on the substrate 10, the unevenness 23 is formed by an imprint method such as nanoimprint. Examples of the imprint method include a UV imprint method and a thermal imprint method, and any of them may be used.

  For example, when the UV imprint method is used, a film mold formed from a Ni master mold in which irregularities having a period of 2 μm and a height of 1 μm are patterned can be used. After the UV curable transparent resin for imprinting is applied to the substrate 10, a film mold is pressed against the surface of the applied resin. Thereafter, ultraviolet light (for example, wavelength 365 nm) is irradiated from the substrate 10 side or the film mold side to cure the resin. After curing, the film mold is peeled to form the first film 121 having the unevenness 23 on the surface.

  In addition, not only acrylic resin materials but also other light transmissive resin materials such as epoxy materials, or light transmissive inorganic materials such as silicon nitride films are formed by coating or vapor deposition. One film 121 may be formed. The first film 121 is the first layer 21 before a part thereof is removed, and a material constituting the first layer 21 can be used.

  Next, as illustrated in FIG. 4C, a second film 122 having a refractive index different from that of the first film 121 is formed on the first film 121. Specifically, an acrylic resin material containing nanoparticles is applied and cured on the first film 121 so as to fill the unevenness 23.

  In addition, not only acrylic resin materials but also other light transmissive resin materials such as epoxy materials, or light transmissive inorganic materials such as silicon nitride films are formed by coating or vapor deposition. Two films 122 may be formed. The second film 122 is the second layer 22 before being partially removed, and a material constituting the second layer 22 can be used.

  Thus, the light control film 120 is formed by stacking the first film 121 and the second film 122. The light control film 120 is a light-transmitting laminated film having a light diffusion structure for diffusing light, and is the light control layer 20 before a part thereof is removed.

  Next, as shown in FIG. 4D, a part of the light control film 120 is removed. Specifically, the irradiated portion is removed by irradiating a predetermined portion of the light control film 120 with the laser light 91 using the laser device 90. In this embodiment mode, a part of the first film 121 and the second film 122 is removed by irradiation with the laser light 91. Details of the laser beam 91 will be described later.

  In this embodiment, the outer peripheral portion of the light control film 120 is removed. As shown in FIG. 1, the substrate 10 and the sealing substrate 40 are not interposed through the light control film 120 (light control layer 20) as shown in FIG. 1 by using the removed portion 60 that is the portion from which the light control film 120 has been removed. Can be glued to. Thereby, the light control layer 20 can be prevented from being exposed to the outside of the sealing substrate 40. That is, since the light control layer 20 can be sealed in the sealing space 70, it is possible to suppress moisture from entering through the light control layer 20.

  In the present embodiment, the light control film 120 is divided into a plurality of parts in order to simultaneously manufacture a plurality of organic EL elements 1. Specifically, as shown in FIG. 4D, the light control film 120 is removed in a lattice shape, that is, the removed portion 60 is formed in a lattice shape. As a result, four light control layers 20 are formed on the substrate 10 as shown in FIG.

  Thereafter, the first electrode 31, the organic layer 32, and the second electrode 33 are formed in this order on the light control layer 20, and then sealed using the sealing substrate 40. Finally, the four organic EL elements 1 can be manufactured simultaneously by dividing the substrate 10 and the sealing substrate 40. Thus, manufacturing cost can be reduced by manufacturing a plurality of organic EL elements 1 from one substrate 10 at the same time (so-called multiple processing).

  Note that only one light control layer 20 and only one light emitting laminate 30 may be formed on one substrate 10. In this case, what is necessary is just to form the to-be-removed part 60 of the frame shape along outer periphery instead of a grid | lattice form.

[Laser light]
Here, the laser device 90 and the laser beam 91 according to the present embodiment will be described.

As the laser device 90, a device that emits an arbitrary laser beam that can process the material for forming the first film 121 and the second film 122 can be used. As the laser device 90, for example, a gas laser, an excimer laser, a solid-state laser, or the like can be used. A CO ₂ laser or the like can be used as the gas laser. As the excimer laser, a KrF laser, a XeCl laser, or the like can be used. As the solid-state laser, a YVO4 laser, a YAG laser, or the like can be used. For example, these laser devices emit laser light having a wavelength of the second harmonic, third harmonic, fourth harmonic, or the like in the ultraviolet region as laser light 91.

  The laser beam 91 is a pulse laser beam. The pulse width of the laser beam 91 is, for example, nanoseconds to femtoseconds. In the present embodiment, for example, the laser beam 91 is a pulsed laser beam having a pulse width of 10 ps or less. This enables ablation processing by multiphoton absorption, not thermal processing. That is, since it can be processed with high accuracy, the end surface 21a and the end surface 22a can be easily formed into desired shapes.

  In the present embodiment, the laser device 90 includes an optical system such as an aperture (aperture), a lens, and a beam homogenizer. The aperture is, for example, a shielding plate that cuts a portion having a low energy density at the end of the laser beam 91. The lens is an optical element that condenses the laser light 91 at a predetermined position (focus position). The beam homogenizer is an optical element that makes the intensity distribution of the laser light 91 substantially uniform.

  The laser device 90 controls the beam characteristics such as the focus position and the intensity distribution by controlling the size of the aperture, the numerical aperture (NA) of the lens, the beam homogenizer, and the like. Thereby, the taper angle of the end surface 21a or the end surface 22a of the part 60 to be removed can be controlled.

  For example, the laser device 90 emits pulse laser light having a substantially uniform intensity distribution as laser light 91 by a beam homogenizer. Specifically, the intensity distribution of the laser beam 91 is substantially uniform with respect to the scanning direction of the laser beam 91. Alternatively, the intensity distribution of the laser beam 91 may be substantially uniform with respect to a direction orthogonal to the scanning direction. That is, the intensity distribution of the laser beam 91 may be approximately two-dimensionally uniform.

  Hereinafter, as an example, a case where the taper shape is controlled by adjusting the numerical aperture of the lens of the laser device 90 will be described with reference to FIG.

  FIG. 5 is a schematic diagram for explaining the relationship between the numerical aperture NA of the lens 92 of the laser device 90 and the beam shape of the laser light 91. Specifically, FIG. 5A schematically shows the beam shape when the numerical aperture NA is small, and FIG. 5B schematically shows the beam shape when the numerical aperture NA is large.

  As shown in FIG. 5, the greater the numerical aperture, the stronger the degree of condensing of the laser light 91 by the lens 92. In other words, the greater the numerical aperture, the smaller the depth of focus, which is the distance from the lens 92 to the focal point. That is, as the numerical aperture increases, the laser beam 91 is condensed by the lens 92 at a portion closer to the lens 92.

  Therefore, when the distance from the lens 92 to the light control film 120 is the same, as shown in FIG. 5A, when the numerical aperture is small, the taper angle becomes large, as shown in FIG. Thus, when the numerical aperture is large, the taper angle is small. Further, the irradiation range of the laser beam 91 varies depending on the numerical aperture. For example, as shown in FIG. 5A, when the numerical aperture is small, the laser irradiation range is widened, and the removed portion 60 is large. On the other hand, as shown in FIG. 5B, when the numerical aperture is large, the laser irradiation range is narrowed and the removed portion 60 is small.

In the present embodiment, the progress of the laser light 91 varies depending on the difference in refractive index between the first film 121 and the second film 122. For this reason, the to-be-removed part 60 is formed so that the taper angles of the end faces are different from each other only by irradiating the first film 121 and the second film 122 with the laser light 91. Specifically, when the first film 121 and the second film 122 are removed, the taper angle θ ₁ of the end face 21 a and the taper angle θ _{2 of the} end face 22 a can be set by simply irradiating one pulse laser beam. Can be different. That is, it is not necessary to adjust the optical system of the laser device 90 in detail, and end faces with different taper angles can be easily formed.

  FIG. 6 is a cross-sectional SEM (Scanning Electron Microscope) image near the end of the light control layer 20 according to the present embodiment.

  As shown in FIG. 6, the taper angle of the end surface 21 a of the first layer 21 is different from the taper angle of the end surface 22 a of the second layer 22. In this way, the irradiated portion is removed by one-time irradiation of the pulse laser beam (that is, the portion to be removed 60 is formed), and the end surface 21a and the end surface 22a are tapered at different angles.

  The laser device 90 includes, for example, a galvano optical scanner. Thereby, the irradiation position of the laser beam 91 can be moved (scanned). Alternatively, the stage on which the substrate 10 is placed may be moved.

[Effects, etc.]
As described above, the organic EL element 1 according to the present embodiment includes the light-transmitting substrate 10, the light control layer 20 provided on the substrate 10 and having a light diffusion structure that diffuses light, and the light control. A light emitting layered body 30 provided on the layer 20, the light control layer 20 having a refractive index different from that of the first layer 21 and the first layer 21, and the first layer 21 provided on the first layer 21. The taper angle θ ₁ formed by the end surface 21 a of the first layer 21 with respect to the substrate 10 is different from the taper angle θ ₂ formed by the end surface of the second layer 22 with respect to the substrate 10.

  Thereby, since the light control layer 20 includes the first layer 21 and the second layer 22, the light emitted from the light emitting laminate 30 can be more effectively diffused (scattered). For example, the light can be scattered more effectively by forming the unevenness 23 as a light diffusion structure at the interface between the first layer 21 and the second layer 22 as in this embodiment. At this time, since the second layer 22 also functions as a flattening layer for flattening the unevenness 23, the light emitting laminate 30 can be formed with high accuracy. That is, the reliability of the organic EL element 1 can be improved.

Further, since the end face 21a and the end surface 22a of the light control layer 20 is inclined with respect to the substrate 10, when the light-emitting laminated body 30 is emitted reaches the end surface 21a or the end surface 22a, the critical angle theta _c greater than the angle It becomes easy to enter. For this reason, of the light propagating in the first layer 21 or the second layer 22, most of the light reaching the end face 21a or the end face 22a is totally reflected by the end face 21a or the end face 22a. At this time, since the taper angle theta ₁ of the end face 21a of the first layer 21 and the taper angle theta ₂ of the end face 22a of the second layer 22 is different, is more efficiently total reflection light propagating in each layer Can be removed from the substrate 10. Therefore, the light extraction efficiency of the organic EL element 1 can be increased.

Further, for example, when the refractive index of the first layer 21 is n ₁ and the first taper angle is θ ₁ , cos θ ₁ > 1 / n ₁ is satisfied, and the refractive index of the second layer 22 is n ₂ , When the 2 taper angle is θ ₂ , cos θ ₂ > 1 / n ₂ is satisfied.

  Thereby, the parallel light 81 propagating in the first layer 21 substantially in parallel is totally reflected by the end face 21a, and the parallel light 82 propagating in the second layer 22 in parallel is totally reflected by the end face 22a. it can. Similarly, the light propagating downward by the parallel light 81 and the parallel light 82 can also be totally reflected by the end face 21a or the end face 22a. Therefore, more light can be totally reflected by the end surface 21a or the end surface 22a, and light leaking to the outside from the end surface 21a or the end surface 22a can be suppressed, so that the light extraction efficiency can be further enhanced. .

  For example, the end surface 21a of the first layer 21 and the end surface 22a of the second layer 22 are formed by laser processing.

  Thereby, since the end surface 21a and the end surface 22a can be formed with high precision by laser processing, the light extraction efficiency can be increased.

  In addition, for example, in the method of manufacturing the organic EL element 1 according to the present embodiment, a step of forming the light control film 120 having a light diffusion structure for diffusing light on the substrate 10 and a part of the light control film 120. And the step of forming the light emitting laminate 30 on the light control film 120. In the step of forming the light control film 120, the first film 121 is formed on the substrate 10, and the first film 121 is formed. In addition, in the step of forming and removing the second film 122 having a refractive index different from that of the first film 121, a part of the first film 121 and the second film 122 is removed by irradiation with the laser light 91. .

  Thereby, the taper can be easily formed on the end face by forming the removed portion 60 by laser processing. At this time, by adjusting the optical system of the laser device 90, the beam characteristics (beam shape, etc.) of the laser light 91 can be easily changed, so that the taper shape can be easily changed to a desired shape. . Therefore, it is possible to easily adjust the shape of the end face so that the light from the light emitting laminate 30 is totally reflected, so that the light extraction efficiency can be increased. Moreover, since the end face can be processed with high precision by laser processing, the reliability of the organic EL element 1 can be increased.

Further, for example, the first taper angle θ ₁ formed by the end surface 21 a of the removed portion of the first film 121 with respect to the substrate 10 is defined by the end surface 22 a of the removed portion of the second film 122 formed by the substrate 10. It is different from the second taper angle θ _2.

Thus, since the different taper angle theta ₁ of the end face 21a of the first layer 21 and the taper angle theta ₂ of the end face 22a of the second layer 22, is more efficiently total reflection light propagating in each layer Can be removed from the substrate 10.

For example, when the refractive index of the first film 121 is n ₁ and the first taper angle is θ ₁ , cos θ ₁ > 1 / n ₁ is satisfied, and the refractive index of the second film 122 is n ₂ , When the 2 taper angle is θ ₂ , cos θ ₂ > 1 / n ₂ is satisfied.

  Thereby, the end face 21a and the end face 22a can be formed with high precision by laser processing, and thus the light extraction efficiency can be increased.

  For example, the laser beam 91 is a pulse laser beam having a pulse width of 10 ps or less and a substantially uniform intensity distribution.

  Thereby, since the laser beam 91 having a pulse width of 10 ps or less is irradiated, the influence of heat by the laser beam 91 can be suppressed. Furthermore, since the intensity distribution is substantially uniform, the roughness of the processed surface of the removed portion 60 can be suppressed. That is, since the processed surface can be made clean, the reliability of the organic EL element 1 can be improved.

(Other)
As described above, the organic EL element according to the present invention has been described based on the above embodiment and the modifications thereof, but the present invention is not limited to the above embodiment.

For example, in the above embodiment, the unevenness 23 is formed as the light diffusion structure between the first layer 21 and the second layer 22, but the present invention is not limited to this. The plane between the first layer 21 and the second layer 22 may be a flat surface or a curved surface. Since the different refractive index of the first layer 21 n ₁ and the refractive index n ₂ of the second layer 22, by the light even in the case of the plane is refracted according to the incident angle, it is possible to scatter light.

  Further, for example, in the above-described embodiment, the example in which both the first layer 21 and the second layer 22 include diffusion particles has been described, but the present invention is not limited thereto. One or both of the first layer 21 and the second layer 22 may not contain diffusing particles.

Further, for example, in the above-described embodiment, on the condition that the parallel light 81 and the parallel light 82 are totally reflected, the taper angles θ ₁ and θ ₂ and the refractive indexes n ₁ and n ₂ of the end surface 21a and the end surface 22a (See (Equation 1) and (Equation 2)), but is not limited thereto. For example, cos θ ₁ = 1 / n ₁ and cos θ ₂ = 1 / n ₂ may be used.

Or it is good also as conditions on the condition that the light which progresses diagonally below rather than parallel light is totally reflected. That is, cos θ ₁ <1 / n ₁ and cos θ ₂ <1 / n ₂ may be satisfied.

For example, when the sealing space 70 is filled with a predetermined filler refractive index _{n x,} instead of equation (1) and (Equation _{2), cosθ 1 <n x} / n 1 and,, cos [theta] ₂ <n _x / n ₂ may be satisfied.

  Further, for example, in the present embodiment, the laser beam 91 has been described as an example having a substantially uniform intensity distribution, but the present invention is not limited thereto. The intensity distribution of the laser beam 91 may be a Gaussian distribution.

  Further, for example, in the present embodiment, laser processing is used for forming the removed portion 60, that is, for forming the end face 21a and the end face 22a, but the present invention is not limited to this. The removed portion 60 may be formed by wiping the applied film forming material or by wet patterning using mask control and photolithography.

  In addition, the embodiment can be realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present invention, or a form obtained by subjecting each embodiment to various modifications conceived by those skilled in the art. Forms are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Organic EL element 10 Board | substrate 20 Light control layer 21 1st layer 21a, 22a End surface 22 2nd layer 23 Concavity and convexity (light diffusion structure)
30 Light-Emitting Laminate 60 Removed Part 91 Laser Light 120 Light Control Film 121 First Film 122 Second Film

Claims (7)

A translucent substrate;
A light control layer provided on the substrate and having a light diffusion structure for diffusing light;
A light emitting laminate provided on the light control layer,
The light control layer includes
The first layer;
A refractive index different from that of the first layer, and a second layer provided on the first layer,
The first taper angle formed by the end surface of the first layer with respect to the substrate is different from the second taper angle formed by the end surface of the second layer with respect to the substrate. When the refractive index of the first layer is n ₁ and the first taper angle is θ ₁ ,
cos θ ₁ > 1 / n ₁ is satisfied, and
When the refractive index of the second layer is n ₂ and the second taper angle is θ ₂ ,
The organic EL device according to claim 1, wherein cos θ ₂ > 1 / n ₂ is satisfied. The organic EL element according to claim 1, wherein an end face of the first layer and an end face of the second layer are formed by laser processing. Forming a light control film having a light diffusion structure for diffusing light on a substrate;
Removing a part of the light control film;
Forming a light emitting laminate on the light control film,
In the step of forming the light control film,
Forming a first film on the substrate;
Forming a second film having a refractive index different from that of the first film on the first film;
In the removing step, a method of manufacturing an organic EL element in which a part of the first film and the second film is removed by irradiating a laser beam. The first taper angle formed by the end surface of the removed portion of the first film with respect to the substrate is different from the second taper angle formed by the end surface of the removed portion of the second film with respect to the substrate. The manufacturing method of the organic EL element of Claim 4. When the refractive index of the first film is n ₁ and the first taper angle is θ ₁ ,
cos θ ₁ > 1 / n ₁ is satisfied, and
When the refractive index of the second film is n ₂ and the second taper angle is θ ₂ ,
The method for manufacturing an organic EL element according to claim 5, wherein cos θ ₂ > 1 / n ₂ is satisfied. The method for manufacturing an organic EL element according to any one of claims 4 to 6, wherein the laser light is pulse laser light having a pulse width of 10 ps or less and a substantially uniform intensity distribution.