Light-emitting apparatus and method for forming the same

Abstract

In a light-emitting apparatus, a face of a substrate on which a light-emitting device is formed is an uneven surface having a plurality of asperities. The mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by a light-emitting layer and no more than two hundred times the longest wavelength. The arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30°, inclusive. Therefore, the apparatus emits substantially a greater amount of light from a light extraction side and has less brightness unevenness than a light-emitting apparatus with no uneven surface.

1 . A light-emitting apparatus comprising a substrate, a middle layer provided on the substrate, and a light-emitting device provided on the middle layer, 
 wherein the device includes a light-emitting layer located between a pair of electrodes, a face of the middle layer on which the light-emitting device is formed is an uneven surface having a plurality of asperities, the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein at least one of the following requirements (i)-(vi) is satisfied:    (i) the arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30°, inclusive;    (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 35;    (iii) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.008 and 0.09, inclusive;    (iv) the ratio Ra/S of the arithmetic mean roughness Ra to the mean spacing S of peaks is in a range between 0.009 and 0.10, inclusive;    (v) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.05 and 0.22, inclusive; and    (vi) the ratio Rz/S of the ten-point height of irregularities Rz to the mean spacing S of peaks is in a range between 0.05 and 0.25, inclusive.    
   
   
       2 . The apparatus according to  claim 1 , wherein at least the requirement (i) is satisfied.  
   
   
       3 . The apparatus according to  claim 1 , wherein at least the requirement (ii) is satisfied.  
   
   
       4 . The apparatus according to  claim 1 , wherein at least the requirement (iii) is satisfied.  
   
   
       5 . The apparatus according to  claim 1 , wherein at least the requirement (iv) is satisfied.  
   
   
       6 . The apparatus according to  claim 1 , wherein at least the requirement (v) is satisfied.  
   
   
       7 . The apparatus according to  claim 1 , wherein at least the requirement (vi) is satisfied.  
   
   
       8 . The apparatus according to  claim 1 , wherein the light-emitting device is curved along the uneven surface.  
   
   
       9 . The apparatus according to  claim 8 , wherein the light-emitting layer has a first face at a side facing the substrate and a second face that is opposite from the first face, wherein the first and second faces are curved along the uneven surface, and the projections of the first face correspond to the depressions of the second face, and the depressions of the first face correspond to the projections of the second face.  
   
   
       10 . The apparatus according to  claim 8 , wherein the electrodes and the light-emitting layer are each formed to have a constant thickness.  
   
   
       11 . The apparatus according to  claim 1 , wherein a prism sheet is provided on a side where light generated by the light-emitting layer is extracted.  
   
   
       12 . The apparatus according to  claim 1 , wherein the light-emitting device is an organic electroluminescent device.  
   
   
       13 . A light-emitting apparatus comprising a substrate and a light-emitting device provided on the substrate, 
 wherein the device includes a light-emitting layer located between a pair of electrodes, one of the electrodes that is closer to the substrate has a face that faces the light-emitting layer and is an uneven surface having a plurality of asperities, the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein at least one of the following requirements (i)-(vi) is satisfied:    (i) the arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30°, inclusive;    (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 35°;    (iii) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.008 and 0.09, inclusive;    (iv) the ratio Ra/S of the arithmetic mean roughness Ra to the mean spacing S of peaks is in a range between 0.009 and 0.10, inclusive;    (v) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.05 and 0.22, inclusive; and    (vi) the ratio Rz/S of the ten-point height of irregularities Rz to the mean spacing S of peaks is in a range between 0.05 and 0.25, inclusive.    
   
   
       14 . The apparatus according to  claim 13 , wherein at least the requirement (i) is satisfied.  
   
   
       15 . The apparatus according to  claim 13 , wherein at least the requirement (ii) is satisfied.  
   
   
       16 . The apparatus according to  claim 13 , wherein at least the requirement (iii) is satisfied.  
   
   
       17 . The apparatus according to  claim 13 , wherein at least the requirement (iv) is satisfied.  
   
   
       18 . The apparatus according to  claim 13 , wherein at least the requirement (v) is satisfied.  
   
   
       19 . The apparatus according to  claim 13 , wherein at least the requirement (vi) is satisfied.  
   
   
       20 . The apparatus according to  claim 13 , wherein the light-emitting layer is curved along the uneven surface.  
   
   
       21 . The apparatus according to  claim 20 , wherein the light-emitting layer has a first face at a side facing the substrate and a second face that is opposite from the first face, wherein the first and second faces are curved along the uneven surface, and the projections of the first face correspond to the depressions of the second face, and the depressions of the first face correspond to the projections of the second face.  
   
   
       22 . The apparatus according to  claim 20 , wherein one of the electrodes, which is opposite to the substrate, and the light-emitting layer are each formed to have a constant thickness.  
   
   
       23 . The apparatus according to  claim 13 , wherein a prism sheet is provided on a side where light generated by the light-emitting layer is extracted.  
   
   
       24 . The apparatus according to  claim 13 , wherein the light-emitting device is an organic electroluminescent device.  
   
   
       25 . A light-emitting apparatus comprising a substrate and a light-emitting device provided on the substrate, 
 wherein the device includes a light-emitting layer located between a pair of electrodes, the light-emitting layer has a first face at a side facing the substrate and a second face that is opposite from the first face, wherein the first and second faces are each uneven surface having a plurality of asperities, the projections of the first face correspond to the depressions of the second face, and the depressions of the first face correspond to the projections of the second face, and wherein, on each face, the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein at least one of the following requirements (i)-(vi) is satisfied:    (i) the arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30°, inclusive;    (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 35°;    (iii) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.008 and 0.09, inclusive;    (iv) the ratio Ra/S of the arithmetic mean roughness Ra to the mean spacing S of peaks is in a range between 0.009 and 0.10, inclusive;    (v) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.05 and 0.22, inclusive; and    (vi) the ratio Rz/S of the ten-point height of irregularities Rz to the mean spacing S of peaks is in a range between 0.05 and 0.25, inclusive.    
   
   
       26 . A method for manufacturing a light-emitting apparatus having a light-emitting layer, comprising: 
 preparing a substrate;    forming a middle layer on the substrate;    forming an uneven surface having a plurality of asperities on a face of the middle layer, wherein the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein the uneven surface is formed such that at least one of the following requirements (i)-(vi) is satisfied:    (i) the arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30° inclusive;    (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 35°;    (iii) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.008 and 0.09, inclusive;    (iv) the ratio Ra/S of the arithmetic mean roughness Ra to the mean spacing S of peaks is in a range between 0.009 and 0.10, inclusive;    (v) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.05 and 0.22, inclusive; and    (vi) the ratio Rz/S of the ten-point height of irregularities Rz to the mean spacing S of peaks is in a range between 0.05 and 0.25, inclusive, and    forming on the uneven surface a light-emitting device having the light-emitting layer and a pair of electrodes between which the light-emitting layer is located such that the light-emitting device is curved along the uneven surface.    
   
   
       27 . A method for manufacturing a light-emitting apparatus having a light-emitting layer, comprising: 
 preparing a substrate;    forming a first electrode on the substrate;    forming an uneven surface having a plurality of asperities on a face of the first electrode, wherein the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein the uneven surface is formed such that at least one of the following requirements (i)-(vi) is satisfied:    (i) the arithmetic mean slope Δa of the uneven surface is in a range between 4° and 30°, inclusive;    (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 35°;    (iii) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.008 and 0.09, inclusive;    (iv) the ratio Ra/S of the arithmetic mean roughness Ra to the mean spacing S of peaks is in a range between 0.009 and 0.10, inclusive;    (v) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.05 and 0.22, inclusive; and    (vi) the ratio Rz/S of the ten-point height of irregularities Rz to the mean spacing S of peaks is in a range between 0.05 and 0.25, inclusive,    forming on the uneven surface the light-emitting layer such that the light-emitting layer is curved along the uneven surface; and    forming a second electrode on the light-emitting layer so that the light-emitting layer is located between the first electrode and the second electrode, thereby forming a light emitting device.