Organic electroluminescent light emitting device and method for manufacturing the same

Abstract

According to one embodiment, an organic electroluminescent light emitting device includes a transparent substrate, an intermediate layer, a first electrode, an organic light emitting layer, and a second electrode. The intermediate layer includes a plurality of fine particles and a flattened layer. The fine particles are adhered to a major surface of the transparent substrate. The flattened layer covers the fine particles and has a refractive index different from a refractive index of the fine particles. The flattened layer is transparent. The first electrode is provided on the intermediate layer. The first electrode is transparent. The organic light emitting layer is provided on the first electrode. The second electrode is provided on the organic light emitting layer.

1 - 20 . (canceled) 
     
     
         21 . An organic electroluminescent light emitting device, comprising:
 a transparent substrate having a major surface;   an intermediate layer including a plurality of fine particles and a flattened layer, the fine particles being adhered to the major surface, the flattened layer covering the fine particles and having a refractive index different from a refractive index of the fine particles, the flattened layer being transparent;   a first electrode provided on the intermediate layer, the first electrode being transparent;   an organic light emitting layer provided on the first electrode; and   a second electrode provided on the organic light emitting layer,   a ratio of an area of the fine particles when projected onto a plane normal to a first direction from the transparent substrate toward the second electrode, to a unit area of the major surface when viewed along the first direction, is not less than 40% and not more than 70%.   
     
     
         22 . The device according to  claim 21 , wherein the particles change a direction of a light emitted from the organic light emitting layer by at least one of scattering and refracting. 
     
     
         23 . The device according to  claim 21 , wherein an average diameter of the fine particles is not less than 200 nanometers and not more than 1.5 micrometers. 
     
     
         24 . The device according to  claim 21 , wherein an average diameter of the fine particles is not less than 600 nanometers and not more than 900 nanometers. 
     
     
         25 . The device according to  claim 21 , wherein a thickness of the intermediate layer is not more than 6 micrometers. 
     
     
         26 . The device according to  claim 21 , wherein the second electrode is reflective. 
     
     
         27 . The device according to  claim 21 , wherein a thickness of a portion of the intermediate layer including the fine particles is not more than 4 times an average diameter of the fine particles. 
     
     
         28 . The device according to  claim 21 , wherein a thickness of an upper side portion of the intermediate layer not including the fine particles is greater than a thickness of a lower side portion of the intermediate layer including the fine particles. 
     
     
         29 . The device according to  claim 21 , wherein a light emitted from the organic light emitting layer is white light. 
     
     
         30 . The device according to  claim 21 , wherein the fine particles are made of an organic material. 
     
     
         31 . The device according to  claim 21 , wherein the fine particles are made of an inorganic material. 
     
     
         32 . The device according to  claim 21 , wherein the fine particles include at least one of silica and titanium oxide. 
     
     
         33 . The device according to  claim 21 , wherein surfaces of the fine particles are modified with quaternary ammonium cation. 
     
     
         34 . The device according to  claim 21 , wherein the flattened layer includes a polysiloxane resin. 
     
     
         35 . The device according to  claim 21 , wherein a difference between a refractive index of the flattened layer and a refractive index of the first electrode, and a difference between the refractive index of the flattened layer and a refractive index of the organic light emitting layer, are smaller than a difference between a refractive index of the fine particles and a refractive index of the first electrode and a difference between the refractive index of the fine particles and the refractive index of the organic light emitting layer. 
     
     
         36 . The device according to  claim 21 , wherein the flattened layer is made of a resin. 
     
     
         37 . A method for manufacturing an organic electroluminescent light emitting device, comprising:
 adhering a plurality of fine particles to a major surface of a transparent substrate, the fine particles being charged with a polarity different from a polarity of charge of the transparent substrate;   forming a flattened layer so as to cover the fine particles and flatten a surface of the flattened layer, the flattened layer having a refractive index higher than a refractive index of the fine particles, the flattened layer being transparent;   forming a first electrode on the flattened layer, the first electrode being transparent;   forming an organic light emitting layer on the first electrode; and   forming a second electrode on the organic light emitting layer,   a ratio of an area of the fine particles when projected onto a plane normal to a first direction from the transparent substrate toward the second electrode, to a unit area of the major surface when viewed along the first direction, is not less than 40% and not more than 70%.   
     
     
         38 . A method for manufacturing an organic electroluminescent light emitting device including a transparent substrate having a major surface, an intermediate layer including a plurality of fine particles and a flattened layer, the fine particles being adhered to the major surface, the flattened layer covering the fine particles and having a refractive index different from a refractive index of the fine particles, the flattened layer being transparent, a first electrode provided on the intermediate layer, the first electrode being transparent, an organic light emitting layer provided on the first electrode, and a second electrode provided on the organic light emitting layer, a ratio of an area of the fine particles when projected onto a plane normal to a first direction from the transparent substrate toward the second electrode, to a unit area of the major surface when viewed along the first direction, being not less than 40% and not more than 70%, the method comprising:
 applying a resin liquid onto the major surface of the transparent substrate, the resin liquid having the fine particles dispersed in a resin forming the flattened layer.