WO2013065178A1

WO2013065178A1 - Light-emitting device

Info

Publication number: WO2013065178A1
Application number: PCT/JP2011/075464
Authority: WO
Inventors: 黒田　和男
Original assignee: パイオニア株式会社
Priority date: 2011-11-04
Filing date: 2011-11-04
Publication date: 2013-05-10

Abstract

A light-emitting device includes: a light-transmitting substrate (10) having a light extraction surface and a concavoconvex surface formed on the side opposite the light extraction surface; reflective films (20) contacting sections of the concavoconvex surface; a high refractive index layer (30) provided on the light-transmitting substrate (10) with the concavoconvex surface and the reflective film (20) surfaces as the interface therebetween, and having a higher refractive index than that of the light-transmitting substrate (10); an organic functional layer (50) containing a light-emitting layer and provided on the high refractive index layer (30); and a reflective electrode (60) provided on the organic functional layer (50). The concavoconvex surface comprises a plurality of concave sections or convex sections which each have a first angled surface (13a) set at an angle to the light extraction surface, and a second angled surface (13b) set at an angle in a direction opposite the direction in which the first angled surface (13a) is angled. Each reflective film (20) covers a first angled surface (13a), and forms a light-reflecting surface angled in relation to the light extraction surface, and positioned along the interface between the light-transmitting substrate (10) and the high refractive index layer (30). The light-transmitting substrate (10) contacts the high refractive index layer (30) along the second angled surfaces (13b), and a light-transmitting surface angled in relation to the plane in which the light-emitting layer extends is formed along the interface between the light-transmitting substrate (10) and the high refractive index layer (30).

Description

Light emitting device

The present invention relates to a light emitting device, and more particularly to a technique for improving light extraction efficiency.

In order to improve the energy efficiency of lighting devices, research and development of light sources to replace incandescent bulbs and fluorescent lamps is ongoing. Recently, high-brightness LEDs (light-emitting diodes) and the like have been regarded as promising candidates, and applied products are actually commercialized. LED lighting is becoming popular in ordinary households as the demand for energy saving increases.

On the other hand, lighting using an organic electroluminescence element (hereinafter referred to as organic EL) is beginning to be commercialized. Since the LED emits light in the form of dots while the organic EL emits light in a planar shape, there is an advantage that a wide and uniform light suitable for illumination light can be obtained without using a diffusion plate.

One of the problems to be solved in an illumination device using an organic EL element (hereinafter referred to as organic EL illumination) is an improvement in light extraction efficiency. For example, in an organic EL lighting device configured by laminating a transparent electrode, an organic functional layer including a light emitting layer, and a metal electrode on a light transmissive substrate such as a glass substrate, the light emitted from the light emitting layer Total reflection is repeatedly attenuated at the interface of the transmissive substrate and the interface between the light transmissive substrate and the light emission space (air). Thereby, only about 20% of the light generated in the light emitting layer can be extracted outside. In order to solve this problem, a structure such as a lens array or a scatterer is provided on the surface of the light transmissive substrate to improve the light extraction efficiency.

Patent Document 1 discloses a light extraction substrate constituting a light emission surface of a light emitting element, a transparent resin layer provided on the light emission surface side of the substrate, and a surface on the light emission surface side of the transparent resin layer. The transparent resin layer has a pyramid-shaped or prism-shaped concavo-convex structure on the light-emitting surface side surface, and the pyramid-shaped or prism-shaped The angle formed by the slope and the light exit surface is more than 40 ° and less than 65 °, and the high refractive index thin film is provided along the concavo-convex structure, and the film thickness at each location is an average film thickness of ± 30%. A surface light source device is disclosed in which the refractive index of the high refractive index thin film is 15 to 30% higher than the refractive index of the transparent resin layer.

In Patent Document 2, in an optical display device in which a light-transmitting layer and a color conversion layer are sequentially laminated on the light-emitting surface side of a planar light emitter, the refractive index of the color conversion layer is set to the light-transmitting property. An optical display device is disclosed in which the refractive index is larger than the refractive index of the layer, and the interface between the color conversion layer and the translucent layer has an uneven shape.

JP 2009-146654 A JP 2000-284705 A

In an organic EL light-emitting device configured by laminating a transparent electrode, an organic functional layer including a light-emitting layer, and a metal electrode on a light-transmitting substrate such as a glass substrate, the factors that reduce the light extraction efficiency are as follows: There are three. (1) Due to the difference in refractive index between the light transmissive substrate and the transparent electrode, total reflection occurs at these interfaces, and the light generated in the light emitting layer does not enter the light transmissive substrate. (2) Due to the difference in refractive index between the light-transmitting substrate and the light emission space (air), total reflection occurs at these interfaces, and the light generated in the light emitting layer is not emitted to the outside. (3) The light transmitted through each layer is attenuated according to the light transmittance of each layer constituting the organic EL light emitting device. In particular, the light incident in an oblique direction with respect to the transparent electrode having a relatively low light transmittance has a significant attenuation because the optical path length becomes long.

Both of the above-described

Patent Documents

1 and 2 are intended to improve the light extraction efficiency by suppressing total reflection occurring at the interface between the light-transmitting substrate and the light emission space (air). It is recognized that the factor 2) is to be eliminated. However, even if the factor (2) is eliminated, unless the total reflection occurring at the interface between the transparent electrode and the light-transmitting substrate is efficiently suppressed (that is, unless the factor (1) is efficiently eliminated). ) The light extraction efficiency cannot be increased dramatically. That is, even in the structures described in

Patent Documents

1 and 2 described above, it is considered that there is a lot of light that cannot be extracted outside, and it is necessary to further improve the light extraction efficiency.

The present invention has been made in view of the above points, and an object of the present invention is to provide a light-emitting device capable of dramatically improving the light extraction efficiency as compared with the prior art.

The light-emitting device according to the present invention includes a light-transmitting substrate having a light extraction surface and a concavo-convex surface formed on the opposite side of the light extraction surface, and a first light reflecting film that is in partial contact with the concavo-convex surface. And a high refractive index layer provided on the light transmissive substrate with the uneven surface and the surface of the first light reflecting film as an interface and having a refractive index higher than the refractive index of the light transmissive substrate, An organic functional layer including a light emitting layer provided on the high refractive index layer; and a second light reflecting film provided on the organic functional layer, wherein the concavo-convex surface is formed on each of the light extraction surfaces. A first inclined surface that is inclined with respect to the first inclined surface, and a second inclined surface that is inclined in a direction opposite to the inclined direction of the first inclined surface, wherein the first light reflecting film includes the first inclined surface. Each of the inclined surfaces of the light-transmitting substrate and the high-refractive-index layer at each of the interfaces. Forming a light reflecting surface inclined with respect to a cutting surface, the light transmitting substrate being in contact with the high refractive index layer on the second inclined surface, and an interface between the light transmitting substrate and the high refractive index layer A light transmission surface inclined with respect to the surface on which the light emitting layer extends is formed.

FIG. 1A is a cross-sectional view showing a configuration of a light emitting device according to an embodiment of the present invention. FIG. 1B is a plan view of the high refractive index layer according to the embodiment of the present invention. FIG.1 (c) is a perspective view which shows 1 unit of the convex part which comprises the uneven | corrugated surface of the high refractive index layer based on the Example of this invention. 2A is a plan view showing the structure of the organic EL element according to the embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line 2b-2b in FIG. 2A. FIGS. 3A to 3C are cross-sectional views illustrating paths until light generated in the organic functional layer is emitted to the outside in the light emitting device according to the embodiment of the invention. FIGS. 4A to 4C are cross-sectional views illustrating paths until light generated in the organic functional layer is emitted to the outside in the light emitting device according to the embodiment of the invention. FIG. 5A and FIG. 5B are cross-sectional views illustrating paths until light emitted from the organic functional layer is emitted to the outside in the light emitting device according to the embodiment of the invention. 6A and 6B are ray tracing diagrams in the light extraction structure of the light emitting device according to the example of the present invention. FIG. 7 is a ray tracing diagram in the light extraction structure according to the comparative example. FIG. 8A is a plan view of a light transmissive substrate according to an embodiment of the present invention. FIG.8 (b) is a perspective view which shows 1 unit of the convex part which comprises the uneven | corrugated surface of the high refractive index layer based on the Example of this invention. FIG. 9A and FIG. 9B are plan views of the high refractive index layer according to the example of the present invention. FIG. 10A and FIG. 10B are plan views of the high refractive index layer according to the example of the present invention. FIG. 11A and FIG. 11C are plan views of the high refractive index layer according to the example of the present invention. FIG.11 (b) is a perspective view which shows 1 unit of the convex part which comprises the uneven | corrugated surface of the high refractive index layer based on the Example of this invention. It is a top view of the high refractive index layer which concerns on the Example of this invention. It is sectional drawing which shows the structure of the light-emitting device based on the Example of this invention. It is sectional drawing which shows the structure of the light-emitting device based on the Example of this invention. It is sectional drawing which shows the structure of the light-emitting device based on the Example of this invention. FIG. 16A and FIG. 16B are perspective views of a light transmissive substrate according to an embodiment of the present invention. FIG. 17A and FIG. 17B are cross-sectional views showing a part of the configuration of the light emitting device according to the example of the present invention. FIG. 18A is a cross-sectional view showing a part of the configuration of the light emitting device according to the example of the present invention. FIG. 18B is a plan view of the high refractive index layer according to the example of the present invention. FIG.18 (c) is a perspective view which shows 1 unit of the convex part which comprises the uneven | corrugated surface of the high refractive index layer based on the Example of this invention. It is sectional drawing which shows a part of structure of the light-emitting device based on the Example of this invention. FIG. 20A is a cross-sectional view showing a configuration of a light emitting device according to an example of the present invention. FIG. 20B is a cross-sectional view showing a part of the configuration of the light emitting device according to the example of the present invention. It is sectional drawing which shows a part of structure of the light-emitting device based on the Example of this invention. 22 (a) to 22 (d) are cross-sectional views illustrating a method for manufacturing a light emitting device according to an embodiment of the present invention. It is sectional drawing which shows a part of structure of the light-emitting device based on the Example of this invention. 24 (a) to 24 (d) are cross-sectional views illustrating a method for manufacturing a light emitting device according to an embodiment of the present invention. 25 (a) to 25 (c) are cross-sectional views illustrating a method for manufacturing a light emitting device according to an embodiment of the present invention. FIG. 26A is a perspective view showing a configuration of a light emitting device according to an example of the present invention. FIG.26 (b) is a top view of the high refractive index layer based on the Example of this invention. FIG.26 (c) is a perspective view which shows 1 unit of the convex part which comprises the uneven | corrugated surface of the high refractive index layer based on the Example of this invention. FIG. 27A is a perspective view showing a configuration of a light emitting device according to an example of the present invention. FIG. 27B is a plan view of the high refractive index layer according to the embodiment of the present invention. It is a top view of the high refractive index layer which concerns on the Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, substantially the same or equivalent components and parts are denoted by the same reference numerals.

FIG. 1A is a cross-sectional view showing a configuration of a light emitting device 1 according to Example 1 of the present invention. FIG. 1B is a plan view of the high refractive index layer 30 constituting the light emitting device 1 as viewed from the direction of the arrow shown in FIG. The light emitting device 1 is configured by laminating a light transmissive substrate 10, a high refractive index layer 30, a transparent electrode 40, an organic functional layer 50 including a light emitting layer, and a reflective electrode 60, and between the transparent electrode 40 and the reflective electrode 60. This is a so-called bottom emission type organic EL light emitting device that extracts light generated in the light emitting layer by applying a voltage to the surface of the light transmissive substrate 10.

The light-transmitting substrate 10 is a plate-like member having a thickness of, for example, about 500 μm made of a light-transmitting material such as glass or resin. The light extraction surface of the light-transmissive substrate 10 is a flat surface and is in contact with air (refractive index 1) filling the light emission space. When the light transmissive substrate 10 is made of glass, for example, the refractive index is about 1.5. The surface opposite to the light extraction surface of the light transmissive substrate 10 has a concavo-convex structure composed of a plurality of quadrangular pyramid-shaped recesses as shown in FIG. The light transmitting substrate 10 may be a laminate of two or more different materials having the same refractive index.

The high refractive index layer 30 is composed of a light transmissive member having a refractive index higher than the refractive index of the light transmissive substrate 10 and approximately the same as the refractive index of the transparent electrode 40. The high refractive index layer 30 can be made of, for example, an epoxy resin having a refractive index of about 1.8. The high refractive index layer 30 has an uneven surface that is in close contact with (corresponds to) the uneven surface of the light transmissive substrate 10. That is, the high refractive index layer 30 has a plurality of quadrangular pyramid (pyramid) convex portions 31 corresponding to the plurality of quadrangular pyramid concave portions formed on the light-transmitting substrate 10.

The surface of the convex portion 31 of the high refractive index layer 30 forms an inclined surface that is inclined with respect to the light extraction surface. In addition, since the uneven surface of the high refractive index layer 30 and the uneven surface of the light-transmitting substrate 10 are in close contact with each other, an equivalent inclined surface is also formed on the light-transmitting substrate 10 side. The plurality of convex portions 31 have the same shape and size as each other, and form a periodic structure that is aligned in the vertical direction and the horizontal direction. FIG. 1C is a perspective view showing one unit of the convex portion 31 constituting the concave-convex surface of the photorefractive index layer 30. The size of the convex portion 31 is preferably sufficiently larger than the wavelength of light generated in the organic functional layer 50. The length of one side of the bottom surface of the convex portion 31 is, for example, 10 μm, and the height is, for example, about 14 μm. The plurality of convex portions 31 can be formed by processing the surface of the high refractive index layer 30 using a known surface processing technique such as cutting and polishing, laser processing, chemical etching, or thermal imprinting. Further, the uneven surface of the high refractive index layer 30 may be formed by a method of applying a resin on the uneven surface of the light transmissive substrate 10.

A reflection film 20 constituting the first light reflection film of the present invention is provided on a part of the side surface of the convex portion 31. The reflective film 20 covers two side surfaces adjacent to each other among the four side surfaces of the quadrangular pyramid-shaped convex portion 31. The reflection film 20 is formed so as to cover one side (for example, the surface a1) of the side surfaces of the convex portion 31 facing each other and not cover the other side surface (for example, the surface b). The reflective film 20 is formed so as to cover one side (for example, the surface a2) of the convex portions 31 adjacent to each other and not the other side surface (for example, the surface b). In addition, the reflective film 20 covers the side surfaces of the plurality of convex portions 31 facing in the same direction. The reflective film 20 is made of a material having a high reflectivity, for example, a metal such as Ag or Al. The reflective film 20 is formed, for example, by forming a patterned resist mask on the concavo-convex surface of the high refractive index layer 30 and then applying the above metal to the high refractive index layer 30 through the resist mask by vacuum deposition or sputtering. It can be formed by depositing on an uneven surface. Thus, the high refractive index layer 30 is in contact with both the light transmissive substrate 10 and the reflective film 20. The thickness of the high refractive index layer 30 is, for example, 100 μm, and the surface in contact with the transparent electrode 40 is flat.

The reflection film 20 forms a light reflection surface inclined with respect to the light extraction surface at the interface between the light transmissive substrate 10 and the high refractive index layer 30. On the other hand, at the other interface between the light transmissive substrate 10 on which the light reflecting film 20 is not formed and the high refractive index layer 30, the light transmission inclined with respect to the extending surface of the organic functional layer 50 including the light emitting layer. A surface is formed. On the flat surface of the high refractive index layer 30, an organic EL element configured by laminating a transparent electrode 40, an organic functional layer 50 including a light emitting layer, and a reflective electrode 60 is formed.

2A is a plan view showing a more detailed structure of the organic EL device according to the embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line 2b-2b in FIG. 2A. FIG.

The plurality of transparent electrodes 40 constituting the anode each have a strip shape, extend along the Y direction on the high refractive index layer 30, and are juxtaposed in the X direction at a constant interval. Each of the transparent electrodes 40 is made of a metal oxide conductor such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The refractive index of the transparent electrode 40 is approximately the same as that of the high refractive index layer 30 (with a refractive index of approximately 1.8). A bus line 72 for supplying a power supply voltage to the transparent electrode 40 is formed on each surface of the transparent electrode 40. An insulating film 71 is formed on the high refractive index layer 30 and the transparent electrode 40. In the insulating film 71, stripe-shaped openings each extending in the Y direction are formed. By providing a plurality of openings on the surface of the insulating film 71, a plurality of banks (partition walls) are formed. Each of the openings reaches the transparent electrode 40, and the surface of each transparent electrode 40 is exposed at the bottom of the opening. A hole injection layer 51, a hole transport layer 52, a light emitting layer 53 _R , 53 _G , 53 _B , and an electron transport layer 54 are stacked in this order on the transparent electrode 40 in each opening of the insulating film 71. An organic functional layer 50 is formed. Examples of materials for the hole injection layer 51 and the hole transport layer 52 include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by fluorene groups, hydrazones. Derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon and the like. The light emitting layers 53 _R , 53 _G , and 53 _B are made of a fluorescent organometallic compound that emits red light, green light, and blue light, respectively. The light emitting layers 53 _R , 53 _G , 53 _B are juxtaposed in a state of being separated from each other by the bank of the insulating film 71. That is, the organic functional layer 50 forms a plurality of light emitting regions separated by banks. An electron transport layer 54 is formed so as to cover the surfaces of the light emitting layers 53 _R , 53 _G , 53 _B and the insulating film 71. A band-like reflective electrode 60 constituting a cathode is formed so as to cover the surface of the electron transport layer 54. The reflective electrode 60 is made of a metal such as Al or an alloy having a low work function and high reflectivity. The reflective electrode 60 constitutes the second light reflective film of the present invention. The refractive index of the organic functional layer 50 is approximately the same as that of the transparent electrode 40 and the high refractive index layer 30 (with a refractive index of approximately 1.8).

Thus, the light emitting layers 53 _R , 53 _G , and 53 _B that respectively emit red, green, and blue light are repeatedly arranged in a stripe shape, and from the surface of the light transmissive substrate 10 that serves as a light extraction surface, Red, green, and blue light are mixed at an arbitrary ratio to emit light that is recognized as a single emission color.

3 to 5 are cross-sectional views illustrating some of the paths until the light generated in the organic functional layer 50 is emitted to the outside in the light emitting device 1 according to the embodiment of the present invention described above. In order to facilitate understanding, it is assumed that the light reflecting surface formed by the reflective electrode 60 exists at the depth position of the bottom of the convex portion 31. Since the high refractive index layer 30, the transparent electrode 40, and the organic functional layer 50 have the same refractive index, no refraction or reflection occurs at each interface. Furthermore, since the concavo-convex structure of the light-transmitting substrate 10 and the high refractive index layer is periodic, there is virtually no problem even if it is assumed that the reflective electrode 60 exists at the above position. In this case, the light emitting point is considered to be on the reflective electrode 60.

As shown in FIG. 3A, the light beam A incident from the right side of the normal line n at an incident angle θ ₁ (the light beam incident from the right side of the normal line n is positive) is light formed by the reflective film 20. After being reflected by the reflecting surface a 1, the light passes through the light transmitting surface b on which no reflecting film is formed and enters the light transmitting substrate 10. The light beam A travels straight inside the light-transmitting substrate 10, is reflected by the light reflecting surface a 2 formed by the reflective film 20, and then is emitted from the light extraction surface d to the outside.

As shown in FIG. 3B, the light beam B incident at the incident angle θ ₂ (θ ₁ > θ ₂ ) from the right side of the normal line n is reflected by the light reflecting surface a 1 formed by the reflective film 20. Then, the light passes through the light transmission surface b on which no reflective film is formed, and enters the light transmissive substrate 10. The light beam B travels straight inside the light transmissive substrate 10, is reflected by the light reflecting surface a 2 formed by the reflective film 20, and then is emitted from the light extraction surface d to the outside.

As shown in FIG. 3C, the light ray C incident in parallel to the normal line n is orthogonal to the light reflection surface a1 formed by the reflective film 20, and therefore follows the same path as the incident path, thereby reflecting the electrode 60. It goes to the light reflection surface c formed by the above. After being reflected by the light reflecting surface c, the light beam C is transmitted through the light transmitting surface b on which no reflective film is formed and enters the light transmitting substrate 10. The light beam C travels straight through the light-transmitting substrate 10 and is emitted from the light extraction surface d to the outside.

As shown in FIG. 4A, the light ray D incident at the incident angle θ ₄ (θ ₄ <0) from the left side of the normal line n is reflected by the light reflecting surface a1 formed by the reflective film 20, The light is reflected by the light reflecting surface c formed by the reflecting electrode 60 and is reflected again by the light reflecting surface a1. Thereafter, the light beam D passes through the light transmission surface b on which no reflective film is formed and enters the light transmissive substrate 10. The light beam D travels straight inside the light-transmitting substrate 10, is reflected by the light reflecting surface a 2 formed by the reflective film 20, and then is emitted from the light extraction surface d to the outside.

As shown in FIG. 4B, the reflection film is formed on the light ray E incident from the left side of the normal line n at an incident angle θ ₅ (θ ₅ > critical angle between the high refractive index layer and the light transmitting substrate). Since the incident light is incident on the light transmitting surface b which is not larger than the critical angle, the light transmitting surface b is totally reflected. Thereafter, the light beam E is reflected by the light reflecting surface a1 formed by the reflecting film 20, and then reflected by the light reflecting surface c formed by the reflecting electrode 60, passes through the light transmitting surface b, and passes through the light transmitting substrate 10. Is incident on. The light beam E travels straight in the light transmissive substrate 10 and is emitted to the outside from the light extraction surface d.

As shown in FIG. 4C, the light beam F incident on the high refractive index layer 30 at an angle substantially parallel to the light reflecting surface a1 is transmitted through the light transmitting surface b on which no reflecting film is formed. Incident on the conductive substrate 10. The light beam F travels straight through the light-transmitting substrate 10 and is emitted from the light extraction surface d to the outside, or is totally reflected at the interface d (light extraction surface) between the light-transmitting substrate 10 and air.

As shown in FIG. 5A, the light beam G totally reflected at the interface d between the light transmissive substrate 10 and air is reflected by the light reflecting surface a formed by the reflective film 20. Since the light reflection surface a is inclined with respect to the interface d, the light beam G is incident on the interface d at an incident angle smaller than the critical angle, and is not totally reflected from the light extraction surface d to the outside. Released.

As shown in FIG. 5B, the light beam H that has entered the high refractive index layer 30 through the light transmission surface b on which no reflective film is formed from the light transmissive substrate 10 is formed by the reflective electrode 60. The light is reflected by the light reflecting surface a 1 formed by the light reflecting surface c and the reflecting film 20, passes through the light transmitting surface b where the reflecting film is not formed, and enters the light transmitting substrate 10. The light beam H travels straight inside the light transmissive substrate 10, is reflected by the light reflecting surface a 2 formed by the reflective film 20, and then is emitted from the light extraction surface d to the outside.

As described above, in the light emitting device 1 according to the present example, the light-transmitting substrate 10 has the corresponding unevenness corresponding to the uneven surface including the plurality of quadrangular pyramidal protrusions 31 provided on the surface of the high refractive index layer 30. The reflective film 20 having a double-sided reflective surface partially contacts the uneven surface and the corresponding uneven surface. The high refractive index layer 30 having a higher refractive index than the light transmissive substrate 10 is provided on the light transmissive substrate 10 with the uneven surface of the light transmissive substrate 10 and the surface of the reflective film 20 as an interface. According to such a light extraction structure, the interface between the light transmissive substrate 10 and the high refractive index layer 30 forms an inclined surface inclined with respect to the surface on which the organic functional layer 50 including the light emitting layer extends. The light incident on the interface at an angle greater than the critical angle can be reduced, and total reflection at the interface can be suppressed. Further, the reflection film 20 forms a light reflection surface inclined with respect to the light extraction surface. Thereby, the light totally reflected at the interface (light extraction surface) between the light transmissive substrate 10 and the air or the light incident on the light transmissive substrate 10 through the high refractive index layer 30 is reflected by the reflective film 20. Thereafter, the light can enter the light extraction surface at an incident angle smaller than the critical angle. Therefore, it is possible to prevent the repeated reflection between the light extraction surface and the reflective electrode 60. Further, since the light reflecting surface on which the reflecting film 20 is formed and the light transmitting surface on which the reflecting film is not formed face each other, the light traveling in the high refractive index layer 30 has a relatively short path. So that the light can enter the light-transmitting substrate 10.

FIGS. 6A and 6B are ray tracing diagrams in the light extraction structure of the light emitting device 1 according to the present example, respectively, in which the bottom of one convex portion of the high refractive index layer is divided into five equal parts. A total of 36 rays incident on the high refractive index layer at angles of 10 °, 30 °, 50 °, 70 °, 90 °, 110 °, 130 °, 150 °, and 170 ° at each of the points P1 to P4. It is the result of simulating the course of. In addition, the refractive index n1 of the light-transmitting substrate is 1.5, the refractive index n2 of the high refractive index layer is 1.8, the refractive index n0 of air filling the light emission space is 1, and the light reflecting surface formed by the reflective electrode The angle α formed by c and the side surface of the convex portion of the high refractive index layer is 40 ° (FIG. 6A) and 55 ° (FIG. 6B), and the light reflection surface c formed by the reflective electrode is high. The simulation was carried out assuming that it exists at the depth position of the bottom of the convex part of the refractive index layer. According to the light extraction structure according to this example, all 36 light beams could be emitted to the outside by passing through the light reflection surface c formed by the reflective electrode twice at most.

On the other hand, FIG. 7 is a ray tracing diagram in the light extraction structure according to the comparative example in which the reflective film is not provided on the uneven surface of the light-transmitting substrate, and the bottom of one convex portion of the high refractive index layer is 5 A total of 36 incident on the high refractive index layer 30 at angles of 10 °, 30 °, 50 °, 70 °, 90 °, 110 °, 130 °, 150 °, and 170 ° at each of the equally dividing points P1 to P4. It is the result of simulating the course of light rays of a book. Since the light path has symmetry, in FIG. 7, the light rays incident on the high refractive index layer at the angles of 110 °, 130 °, 50 °, and 170 ° are not displayed. In addition, the refractive index n1 of the light-transmitting substrate is 1.5, the refractive index n2 of the high refractive index layer is 1.8, the refractive index n0 of air filling the light emission space is 1, and the light reflecting surface formed by the reflective electrode The simulation was carried out on the assumption that the angle α formed by c and the side surface of the convex portion was 55 °, and the light reflecting surface c formed by the reflective electrode was present at the depth position of the bottom of the convex portion of the high refractive index layer. According to the light extraction structure according to the comparative example, the number of reflections at the light reflection surface c is 0 to 2 times, and 20 of the light rays are emitted to the outside. It was confirmed that there were few. That is, in a structure having no reflective film on the uneven surface of the light-transmitting substrate, about 44% of light cannot be extracted outside unless it has been reflected by the light reflecting surface c three times or more.

As is clear from the above description, the light emitting device 1 according to the present embodiment has a high refractive index layer having a refractive index substantially equal to that of the transparent electrode 40 between the transparent electrode 40 and the light transmissive substrate 10, Since a double-sided reflective film inclined with respect to the light extraction surface is provided between the transmissive substrate 10 and the high refractive index layer 30, light can be extracted outside with a relatively short optical path length and a relatively small number of reflections. And light extraction efficiency can be dramatically improved.

FIG. 8A is a plan view showing a first modified example of the pattern of the reflective film 20 formed on the uneven surface of the high refractive index layer 30, and FIG. 8B is the reflective film 20 having the modified pattern. It is a perspective view which shows one unit of the convex part 31 in which was formed. As shown in these drawings, the reflective film 20 may be provided so as to cover a substantially half region of each side surface of the quadrangular pyramid-shaped convex portion 31. According to the pattern of the reflective film 20, the light transmission surface is formed on each of the four side surfaces of the quadrangular pyramid-shaped convex portion 31, so that the light emission direction can be dispersed. From the viewpoint of light extraction efficiency, it is preferable to provide the reflective film 20 only on one of the portions facing each other even in such a modified pattern. In the example shown in FIG. 8A, the reflective film 20 is provided only on the portion a1 ′ of the portions a1 ′ and b ′ facing each other. The same applies to the portions a2 ′ and b ′ facing each other between the adjacent convex portions.

FIG. 9A is a plan view showing a second modification of the pattern of the reflective film 20 formed on the concavo-convex surface of the high refractive index layer 30. FIG. As shown in FIG. 9A, the pattern of the reflective film 20 may be a mixed pattern of the reflective film pattern shown in FIG. 1B and the reflective film pattern shown in FIG.

FIG. 9B is a plan view showing a third modification of the pattern of the reflective film 20 formed on the uneven surface of the high refractive index layer 30. The reflective film 20 covers two side surfaces adjacent to each other among the four side surfaces of each of the quadrangular pyramidal convex portions 31. As shown in FIG. 9B, the reflective film 20 may be formed so as to cover side surfaces facing in different directions for each convex portion or for each block composed of a plurality of convex portions. In the example shown in FIG. 9B, the reflective film 20 is arranged in different directions for each block constituted by the four convex portions 31. According to the pattern of the reflection film 20, the light transmission surface that is not covered with the reflection film 20 faces the center of FIG. 9B, and the unit shown in FIG. Uniform light can be obtained.

FIGS. 10A and 10B are plan views showing a first modification of the shape of the convex portion 31 of the high refractive index layer 30. FIG. As shown in these drawings, the shape of one unit of the convex portion 31 may be a triangular pyramid shape. The reflective film 20 is formed so as to cover one of the three side surfaces of the triangular pyramid. Further, as shown in FIG. 10A, the reflective film 20 is formed so as to cover only one of the side surfaces facing each other between adjacent convex portions (for example, the surface a and the surface b). As shown in FIG. 10B, a region that is a light transmission surface that is not covered with a reflective film on both side surfaces facing each other between adjacent convex portions may be included (for example, the surface b1). Surface b2). As described above, the shape of the convex portion 31 is a triangular pyramid, and the reflection film is formed so that both of the side surfaces facing each other between the adjacent convex portions do not become light reflecting surfaces, thereby improving the light extraction efficiency and light. It becomes possible to disperse the release direction. In particular, according to the configuration shown in FIG. 10A, uniform light can be obtained as a whole.

FIG. 11A is a plan view showing a second modification of the shape of the convex portion 31 of the high refractive index layer 30. FIG. FIG. 11B is a perspective view showing one unit of the modified convex portion 31. As shown in these drawings, the shape of one unit of the convex portion 31 may be a conical shape. The reflective film 20 covers a substantially half region of the side surface of the cone. Note that the coverage of the reflective film 20 can be changed as appropriate in consideration of light extraction efficiency and the like. As shown in FIG. 11A, so-called oblique deposition without using a mask by directing the portions covered by the reflective film 20 of the convex portion 31 in the same direction (deposition with respect to the flying direction of the vapor deposition particles). It is possible to form the pattern of the reflective film 20 by the method of performing vapor deposition by inclining the surface, and the manufacture becomes easy. On the other hand, as shown in FIG. 11C, the direction of the portion covered by the reflective film 20 of the convex portion 31 is made different, for example, for each block composed of the plurality of convex portions 31, thereby dispersing the light emission direction. It becomes possible.

As shown in FIG. 12, the plurality of protrusions 31 constituting the uneven surface of the high refractive index layer 30 may be arranged with a gap between adjacent protrusions.

In the above description, the high refractive index layer 30 and the transparent electrode 40 are provided separately. However, as shown in FIG. 13, the high refractive index layer 30 may have the function of a transparent electrode. . That is, in this case, the high refractive index layer 30 is made of a metal oxide conductor such as ITO.

In the above description, the case where the concavo-convex surfaces of the light transmissive substrate 10 and the high refractive index layer 30 have a periodic structure composed of conical concave portions or convex portions is illustrated, but as shown in FIG. The shape, size, and height of the concave portions or convex portions constituting the concavo-convex surface of the transmissive substrate 10 and the high refractive index layer 30 may be random. Such a random concavo-convex surface can be formed using a known surface processing technique such as sandblasting or water blasting. The reflective film 20 is partially formed on the side surface of the convex portion having a random shape and size by so-called oblique vapor deposition or the like.

In the above description, the case where the light transmissive substrate 10 is made of a single material has been exemplified. However, as shown in FIG. 15, the light transmissive substrate 10 is made of different materials having the same refractive index. A laminated substrate obtained by laminating layers may be used. For example, the light-transmitting substrate 10 can be configured by laminating a first layer 10a made of glass and a second layer 10b made of a resin having a refractive index equivalent to that of the first layer 10a. Manufacture is facilitated by selecting a material that is relatively easy to form an uneven surface as the material of the second layer 10b adjacent to the high refractive index layer 30.

Moreover, in the above description, as shown in FIG. 16B, the case where the uneven surface of the light-transmitting substrate 10 is formed by the plurality of conical recesses 12 is illustrated, but FIG. As described above, the uneven surface of the light-transmitting substrate 10 may be formed by the plurality of conical protrusions 11. In this case, the high refractive index layer 30 has an uneven surface constituted by a plurality of conical concave portions corresponding to the convex portions 11 of the light-transmitting substrate 10.

FIG. 17A is a cross-sectional view showing a part of the light emitting device 2 according to Example 2 of the present invention. In the light emitting device 2, the tops of the quadrangular pyramid-shaped protrusions 31 constituting the uneven surface of the high refractive index layer 30 and the valleys between adjacent protrusions are

surfaces

31a and 31b that are substantially parallel to the light extraction surface. Have. The reflective film 20 is not formed on the

surfaces

31a and 31b of the high refractive index layer 30, and the

surfaces

31a and 31b are light transmitting surfaces. That is, the light emitting device 2 according to the present example is inclined with respect to the first light transmission surface formed on the

surfaces

31 a and 31 b parallel to the light extraction surface and the surface on which the organic functional layer 50 extends. A second light transmission surface is formed on the surface 31c.

By using the

surfaces

31a and 31b substantially parallel to the light extraction surface as light transmission surfaces, it is possible to easily extract light rays substantially orthogonal to the light extraction surface to the outside. That is, when a light ray that enters perpendicularly to the surface 31a and the surface 31b is transmitted, the light ray travels straight and enters the light extraction surface also perpendicularly. Light rays that are incident perpendicular to the light extraction surface are not totally reflected by the light extraction surface, and can be extracted directly to the outside. With respect to such straight light, it is possible to improve the light extraction efficiency by extracting the light to the outside without being reflected by the reflective film 20. In addition, since it is the same as that of the light-emitting device 1 which concerns on Example 1 except the above-mentioned, those description is abbreviate | omitted.

Further, as shown in FIG. 17B, the

surfaces

31a and 31b may be covered with the reflective film 20 so that the

surfaces

31a and 31b substantially parallel to the light extraction surface become light transmission surfaces. That is, the thickness of the portion covering the

surfaces

31a and 31b of the reflective film 20 is smaller than the thickness of the portion forming the light reflecting surface. Such a film thickness distribution can be formed by forming the reflective film 20 by so-called oblique deposition.

FIG. 18A is a cross-sectional view showing a part of the light emitting device 2a in which the shape of each of the plurality of convex portions 31 constituting the concavo-convex surface of the high refractive index layer 30 is modified, and FIG. FIG. 18C is a perspective view showing one unit of the modified convex portion 31. FIG. 18C is a plan view of the high refractive index layer 30 having an uneven surface constituted by the convex portion 31 having a different shape. As shown in these drawings, each of the protrusions 31 constituting the uneven surface of the high refractive index layer 30 has a truncated pyramid shape, and its upper base (or lower base) is substantially parallel to the light extraction surface. And has a surface 31d. The reflection film 20 covers two adjacent side surfaces of the truncated pyramid and forms a light reflection surface. On the other hand, the reflective film is not formed on the surface 31d which is the upper base (or the lower base) of the convex portion 31, and the surface 31d forms a light transmission surface.

By making the surface 31d substantially parallel to the light extraction surface a light transmission surface, the light incident perpendicularly to the surface 31d is reflected by the reflection film 20 as in the case of the light emitting device 2 described above. Therefore, the light extraction efficiency can be improved.

In the above description, the case where each shape of the convex portion 31 is a truncated pyramid is illustrated, but the shape of the convex portion 31 may be a truncated cone shape. The uneven surface of the high refractive index layer 30 may be composed of a plurality of frustum-shaped recesses. In this case, the concavo-convex surface of the light-transmitting substrate 10 is constituted by a plurality of frustum-shaped convex portions (see FIG. 19). According to the configuration shown in FIG. 19, since the light transmission surface 31d is located below the reflection film 20, light emitted from the light emitting layer can be incident on the light transmission surface 31d at any angle. Therefore, total reflection occurs on the light transmission surface 31d, and there is a possibility that reflection is repeated between the light transmission surface 31d and the reflection electrode 60. On the other hand, according to the configuration shown in FIG. 18A, the light transmission surface 31d is located above the reflection film, so that light incident at an angle smaller than a predetermined angle when viewed from the bottom surface is reflected by the reflection film 20. The light transmission surface 31d cannot be reached by being blocked by the reflection, and is reflected by the reflection surface 20 and taken out to the outside. That is, repeated reflection between the light transmission surface 31d and the reflective electrode 60 is unlikely to occur.

FIG. 20A is a cross-sectional view illustrating a configuration of the light emitting device 3 according to Example 3 of the invention. The light-emitting device 3 is different from the light-emitting device 1 according to Example 1 described above in the light reflection structure formed along the side surface of the convex portion 31 constituting the concave-convex surface of the high refractive index layer 30. That is, the light reflecting structure according to the present embodiment has a reflective film 20 made of a metal such as Ag or Al having a high reflectance and a material having a refractive index lower than that of the light transmissive substrate 10 (for example, SiO ₂ And the like, and a low-refractive-index film 21 made of a laminated reflective film 22. The laminated reflective film 22 forms a light reflecting surface inclined with respect to the light extraction surface at each interface between the light transmissive substrate 10 and the high refractive index layer 30. 20A illustrates the case where the low refractive index film 21 is in contact with the light-transmitting substrate 10 and the reflective film 20 is in contact with the high refractive index layer 30. The arrangement of the refractive index film 21 may be changed. Since the components other than the laminated reflective film 22 are the same as those of the light-emitting device 1 according to Example 1, the description thereof is omitted.

FIG. 20B is a cross-sectional view showing a light path inside the light-emitting device 3 having the laminated reflective film 22 described above. The light beam I incident on the multilayer reflective film 22 at an incident angle larger than the critical angle from the light transmissive substrate 10 side is totally reflected at the interface between the light transmissive substrate 10 and the low refractive index film 21 and travels toward the light extraction surface. In this case, since no reflection loss occurs, the light extraction efficiency becomes higher compared to the case where reflection by the reflection film 20 is performed. On the other hand, the light beam J incident on the laminated reflective film 22 at an incident angle smaller than the critical angle from the light transmissive substrate 10 side is transmitted through the low refractive index film 21 and reflected by the surface of the reflective film 20 to be reflected on the light extraction surface. Head. In this way, the reflection loss can be reduced by interposing the laminated reflective film 22 composed of the low refractive index film 21 and the reflective film 20 between the light transmissive substrate 10 and the high refractive index layer 30. The extraction efficiency can be further improved.

FIG. 21 is a cross-sectional view showing a modified example of the light reflecting structure formed by the low refractive index film 21 and the reflecting film 20. As shown in FIG. 21, the laminated reflective film 22 a may have a sandwich structure in which the low refractive index film 21 sandwiches the reflective film 20. Thereby, it is possible to totally reflect the light incident on the laminated reflective film 22a from the light transmissive substrate 10 side and the high refractive index layer 30 side, and it is possible to further reduce the reflection loss.

Hereinafter, a method for manufacturing the light emitting device 3 according to Example 3 of the present invention having the multilayer reflective film 22 including the reflective film 20 and the low refractive index film 21 will be described with reference to FIGS. 22 (a) to 22 (d). .

First, a light-transmitting substrate 10 configured by laminating a glass substrate 10a and a resin substrate 10b having an uneven surface is prepared. In addition, the refractive index of the glass substrate 10a and the refractive index of the resin substrate 10b are equivalent. The uneven surface of the resin substrate 10b is formed using a molding technique such as thermal imprinting (FIG. 22A).

Next, a low refractive index film 21 made of SiO ₂ or the like having a lower refractive index than that of the resin substrate 10a and the glass substrate 10b is formed on the uneven surface of the resin substrate 10b by sputtering or the like. Thereafter, the low refractive index film 21 is partially removed by a lift-off method, an etching method, or the like, and the low refractive index film 21 is patterned (FIG. 22B).

Next, the reflective film 20 made of a metal having a high reflectance such as Ag or Al is formed on the uneven surface of the resin substrate 10b by vapor deposition or sputtering. Thereafter, the reflective film 20 is partially removed by a lift-off method, an etching method, or the like, and the reflective film 20 is patterned. The reflective film 20 is laminated on the low refractive index film 21 to form a laminated reflective film 22 along the uneven surface of the resin substrate 10b (FIG. 22C).

Next, the refractive index higher than the refractive index of the resin substrate 10b and the glass substrate 10a and the same refractive index as that of the transparent electrode 40 and the organic functional layer 50 is formed on the uneven surface of the resin substrate 10b on which the multilayer reflective film 22 is formed. A UV curable resin having a rate is applied. Thereafter, the UV curable resin is irradiated with ultraviolet rays to be cured. As a result, the high refractive index layer 30 in contact with both the uneven surface of the light transmissive substrate and the multilayer reflective film 22 is formed on the light transmissive substrate 10 (FIG. 22D).

Next, a transparent conductive film made of a metal oxide conductor such as ITO is formed on the high refractive index layer 30 by sputtering or the like, and this is patterned by etching to form the transparent electrode 40. Next, a photosensitive resist (not shown) is applied so as to cover the transparent electrode 40. Thereafter, a plurality of openings reaching the transparent electrode 40 are formed in the photosensitive resist through exposure and development processing. Thereby, the bank which separates an organic functional layer for every luminescent color is formed. Next, a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer are laminated on the transparent electrode 40 by applying an organic material inside each of the plurality of openings by an inkjet method. The organic functional layer 50 is formed. Next, the reflective electrode 60 is formed by depositing Al as an electrode material in a desired pattern on the organic functional layer 50 by vapor deposition or the like using a mask having an opening corresponding to the pattern of the reflective electrode 60. A sealing layer may be formed on the reflective electrode 60 as necessary. Through the above steps, the light emitting device 3 according to this example is completed.

FIG. 23 is a cross-sectional view showing a modification of the light reflecting structure composed of a reflective film and a low refractive index layer. As shown in FIG. 23, the light reflecting structure 24 is configured by a gap 23 and a light reflecting film 20 provided between the light transmissive substrate 10 and the high refractive index layer 30. The gap 23 may be filled with air or other gas having a lower refractive index than the light-transmitting substrate 10 or may be a vacuum. Since the gap 23 has a lower refractive index than that of the light transmissive substrate 10, the gap 23 exhibits the same function as the low refractive index film 21 described above. That is, the light reflecting structure 24 forms a light reflecting surface inclined with respect to the light extraction surface at each interface between the light transmissive substrate 10 and the high refractive index layer 30. FIG. 23 illustrates the case where the reflective film 20 is in contact with the light-transmitting substrate 10 and the gap portion 23 is in contact with the high refractive index layer 30. However, the arrangement of the reflective film 20 and the gap portion 23 is illustrated. It may be replaced. Since the components other than the light reflecting structure are the same as those of the light emitting device according to the first embodiment, description thereof will be omitted.

Hereinafter, a method for manufacturing a light-emitting device having a light reflection structure including the reflective film 20 and the gap 23 will be described with reference to FIGS.

First, a light-transmitting substrate 10 configured by laminating a glass substrate 10a and a resin substrate 10b having an uneven surface is prepared. In addition, the refractive index of the glass substrate 10a and the refractive index of the resin substrate 10b are equivalent. The uneven surface of the resin substrate 10b is formed by using a molding technique such as thermal imprint (FIG. 24A).

Next, the reflective film 20 made of a metal having a high reflectance such as Ag or Al is formed on the uneven surface of the resin substrate 10b by vapor deposition or sputtering. Thereafter, the reflective film 20 is partially removed by a lift-off method, an etching method, or the like, and the reflective film 20 is patterned (FIG. 24B).

Next, a high refractive index member 30a constituting the high refractive index layer 30 is prepared. The high refractive index resin member 30a is made of an epoxy resin or the like having a refractive index higher than that of the glass substrate 10a and the resin substrate 10b and about the same as that of the transparent electrode 40 and the organic functional layer 50. The high refractive index member 30a has a corresponding uneven surface corresponding to (engaged with) the uneven surface formed on the resin substrate 10b, and a minute protrusion 32 provided on the corresponding uneven surface (FIG. 24C).

Next, the uneven surface of the resin substrate 10b and the corresponding uneven surface of the high refractive index member 30a are brought into contact with each other using the minute protrusion 32 as a spacer. The microprotrusions 32 are in contact with the reflective film 20, and a gap is formed on the reflective film 20. As a result, a light reflecting structure 24 including the reflective film 20 and the gap 23 is formed between the resin substrate 10a and the high refractive index member 30a (FIG. 24D).

Since the process of forming the transparent electrode 40, the organic functional layer 50, and the reflective electrode 60 is the same as that described above, the description thereof is omitted. The reflective film 20 may be formed on the corresponding uneven surface of the high refractive index member 30a, or may be formed on both the resin substrate 10a and the high refractive index member 30a. Further, the fine protrusions 32 functioning as spacers may be provided on the uneven surface of the resin substrate 10b, or may be provided on both the resin substrate 10b and the high refractive index member 30a. Alternatively, a structure separate from the resin substrate 10b and the high refractive index member 30a may be disposed between the uneven surface and the corresponding uneven surface to function as a spacer.

Another method for manufacturing a light emitting device having a light reflecting structure including a reflective film and a gap will be described with reference to FIGS. 25 (a) to 25 (d).
First, a light-transmitting substrate 10 configured by laminating a glass substrate 10a and a resin substrate 10b having an uneven surface is prepared. In addition, the refractive index of the glass substrate 10a and the refractive index of the resin substrate 10b are equivalent. The uneven surface of the resin substrate 10b is formed by using a molding technique such as thermal imprinting.

Next, a high refractive index member 30a constituting the high refractive index layer 30 is prepared. The high refractive index resin member 30a is an epoxy having a refractive index higher than the refractive indexes of the glass substrate 10a and the resin substrate 10b constituting the light transmissive substrate 10 and similar to the refractive indexes of the transparent electrode 40 and the organic functional layer 50. Made of resin. The high refractive index resin member 30a has a corresponding uneven surface corresponding to (engaged with) the uneven surface formed on the resin substrate 10b.

Next, the reflective film 20 made of a metal having a high reflectance such as Ag or Al is formed on the corresponding irregular surface of the high refractive index member 30a by vapor deposition or sputtering. Thereafter, the reflective film 20 is patterned by a lift-off method or an etching method (FIG. 25A).

Next, using the difference in thermal expansion coefficient between the high refractive index member 30 a and the reflective film 20, a buckling structure (sag-like undulation) is formed on the reflective film 20. For example, a buckling structure can be formed in the reflective film 20 by heating the reflective film 20 formed on the high refractive index member 30a at about 100 ° C. and then lowering the temperature to room temperature (FIG. 25B). ).

Next, the concavo-convex surface of the resin substrate 10b and the corresponding concavo-convex surface of the high refractive index member 30a are brought into contact with each other with the reflective film 20 having the buckling structure interposed therebetween. Thus, a light reflecting structure 24a is formed between the resin substrate 10a and the high refractive index member 30a. The light reflecting structure 24a includes the reflecting film 20 and the gap portion 23 generated with the buckling structure of the reflecting film 20 (FIG. 25). (C)).

Since the process of forming the transparent electrode 40, the organic functional layer 50, and the reflective electrode 60 is the same as that described above, the description thereof is omitted.

FIG. 26 (a) is a perspective view showing the configuration of the light-emitting device 4 according to Example 4 of the present invention. FIG. 26B is a plan view of the high refractive index layer 30 constituting the light emitting device 4. FIG. 26C is a perspective view of the convex portion 31 constituting the concave and convex surface formed in the high refractive index layer 30. In FIG. 26 (a), in order to facilitate understanding, a configuration portion composed of the light-transmitting substrate 10 and the high refractive index layer 30, and a configuration composed of the transparent electrode 40, the organic functional layer 50, and the reflection electrode 60. The part is divided and displayed.

In the light emitting device 4, each of the plurality of convex portions 31 constituting the concavo-convex surface of the high refractive index layer 30 is opposite to the first inclined surface 33 a inclined to the light extraction surface and the first inclined surface 33 a. It has the 2nd inclined surface 33b inclined in the direction. That is, the first inclined surface 33a and the second inclined surface 33b correspond to the two side surfaces of the triangular prism as shown in FIG. The plurality of convex portions 31 are arranged without gaps such that the first inclined surfaces and the second inclined surfaces are parallel to each other.

The first inclined surface 33 a is covered with the reflective film 20. The second inclined surface 33b is not covered with a reflective film. The high refractive index layer 30 is provided on the light-transmitting substrate 10 with the uneven surface of the light-transmitting substrate 10 and the surface of the light reflecting film 20 as an interface. The reflection film 20 forms a light reflection surface inclined with respect to the light extraction surface at each interface between the light transmissive substrate 10 and the high refractive index layer 30. According to the concavo-convex structure of the light transmissive substrate 10 and the high refractive index layer 30 according to the present embodiment, a plurality of rectangular (or strip-shaped) light reflecting surfaces facing the same direction are formed by the reflective film 20. It will be. The light transmissive substrate 10 is in contact with the high refractive index layer 30 at the second inclined surface 13b, and is inclined with respect to the surface on which the organic functional layer 50 extends at the interface between the light transmissive substrate 10 and the high refractive index layer 30. A light-transmitting surface is formed.

The organic functional layer 50 is formed on the high refractive index layer 30 with the transparent electrode 40 interposed therebetween. The organic functional layer 50 forms a plurality of

light emitting regions

50a, 50b, 50c separated by banks. The plurality of

light emitting regions

50 a, 50 b, and 50 c each have a rectangular shape, and are juxtaposed in a stripe shape on the high refractive index layer 30 via the transparent electrode 40. Note that light of different emission colors may be generated from the plurality of

light emitting regions

50a, 50b, and 50c.

Each of the plurality of convex portions 31 constituting the concavo-convex surface of the high refractive index layer 30 is provided at a position overlapping the

light emitting regions

50a, 50b, 50c, and extends in a direction parallel to the longitudinal direction of the

light emitting regions

50a, 50b, 50c. is doing. In other words, the intersection line L where the first inclined surface 33a and the second inclined surface 33b intersect extends along the longitudinal direction of the

light emitting regions

50a, 50b, 50c. Further, the length of the protrusion 31 in the extending direction (that is, the length of the crossing line L) is longer than the length of the

light emitting regions

50a, 50b, and 50c in the longitudinal direction.

According to the light emitting device 4 according to the present embodiment, the light extraction efficiency can be improved as in the light emitting device 1 according to the first embodiment. Moreover, since one unit of the convex part 31 which comprises the uneven surface of the high refractive index layer 30 is a simple structure which has two inclined surfaces, formation of an uneven surface becomes easy and it can ensure a high manufacturing yield. It becomes possible. Further, since the light reflecting surface formed on the first inclined surface 33a and the light transmitting surface formed on the second inclined surface 33b are arranged in a single direction, the light reflecting surface and the light transmitting surface are arranged. Optimal value design for improving light extraction efficiency using the surface area ratio as a parameter becomes easy. Such an effect is further promoted by directing the extending direction of the intersection line L in a direction parallel to the longitudinal direction of the

light emitting regions

50a, 50b, and 50c. In addition, each of the light reflecting surfaces formed on the first inclined surface 33a has a rectangular shape (strip shape) and faces a single direction, so that light is emitted from a predetermined angle when the light emitting device is not turned on. When looking at the take-out surface, it is possible to visually recognize a mirror surface with good appearance.

As shown in FIGS. 27A and 27B, the extending direction of each of the plurality of convex portions 31 constituting the uneven surface of the high refractive index layer 30 (that is, the extending direction of the intersection line L) is a light emitting region. It may extend in the direction in which 50a, 50b, 50c are arranged or in the direction perpendicular to the longitudinal direction of the

light emitting regions

50a, 50b, 50c. In this case, the intersection line L may extend so as to straddle the plurality of

light emitting regions

50a, 50b, 50c as shown in FIG. Alternatively, as shown in FIG. 28, each of the protrusions 31 is formed discontinuously in the direction in which the

light emitting regions

50a, 50b, 50c are arranged, and the length of the intersection line L is the same as the direction of the

light emitting regions

50a, 50b, 50c. It may be the same as the length W in the matching width direction.

It should be noted that the configurations shown in the above embodiments can be combined with each other. Moreover, since the concavo-convex surfaces of the light transmissive substrate 10 and the high refractive index layer 30 are in close contact, the reflective film 20 and the low refractive index film 21 may be formed on the light transmissive substrate 10 side. It is good also as forming in the high refractive index layer 30 side.

1, 2, 2a, 3, 4 Light emitting device 10 Light transmissive substrate 20 Reflective film 21 Low refractive index film 22 Laminated reflective film 23 Gap 24 Light reflecting structure 30 High refractive index layer 31 Convex part 33a First inclined surface 33b second inclined surface 40 transparent electrode 50 organic functional layers ₅₃ _R, 53 G, 53 _B emission layer 60 reflective electrode

Claims

A light transmissive substrate having a light extraction surface and an uneven surface formed on the opposite side of the light extraction surface;
A first light reflecting film partially in contact with the uneven surface;
A high refractive index layer provided on the light transmissive substrate with the uneven surface and the surface of the first light reflecting film as an interface and having a refractive index higher than the refractive index of the light transmissive substrate;
An organic functional layer including a light emitting layer provided on the high refractive index layer;
A second light reflecting film provided on the organic functional layer,
The concavo-convex surface has a first inclined surface that is inclined with respect to the light extraction surface, and a second inclined surface that is inclined in a direction opposite to the inclination direction of the first inclined surface,
The first light reflecting film is in contact with each of the first inclined surfaces and forms a light reflecting surface inclined with respect to the light extraction surface at each interface between the light transmissive substrate and the high refractive index layer. And
The light-transmitting substrate is in contact with the high refractive index layer on the second inclined surface;
A light-emitting device, wherein a light-transmitting surface inclined with respect to a surface on which the light-emitting layer extends is formed at an interface between the light-transmitting substrate and the high refractive index layer.
The organic functional layer forms a plurality of light emitting regions juxtaposed in stripes on the high refractive index layer,
2. The light emitting device according to claim 1, wherein an intersection line between the first inclined surface and the second inclined surface extends along a longitudinal direction of each of the light emitting regions.
3. The light emitting device according to claim 2, wherein the sum of the lengths of the intersecting lines on the same line is longer than the length of each light emitting region in the longitudinal direction.
The organic functional layer forms a plurality of light emitting regions juxtaposed in stripes on the high refractive index layer,
2. The light emitting device according to claim 1, wherein an intersection line between the first inclined surface and the second inclined surface extends along a direction in which the plurality of light emitting regions are arranged.
The light-emitting device according to claim 4, wherein the intersection line extends so as to straddle the plurality of light-emitting regions.
5. The light emitting device according to claim 4, wherein the concave portion or the convex portion constituting the uneven surface is formed discontinuously in a direction in which the plurality of light emitting regions are arranged.
The light emitting device according to claim 6, wherein the length of the intersecting line is equal to the width of the light emitting region.
The light emitting device according to claim 1, wherein each of the light reflecting surfaces has a rectangular shape.
The light emitting device according to any one of claims 1 to 7, wherein each of the light reflecting surfaces is parallel to each other.