Organic EL device with protective layer

Abstract

An organic EL device has a structure in which an anode, a hole transporting layer, an organic luminescent layer, and a cathode are disposed on a glass substrate in this order. The organic EL device further has a protective layer covering an outer surface of the structure to protect it from an external environment. The protective layer is formed by an ALE method at a temperature lower than glass transition temperatures materials constituting the hole transporting layer and the organic luminescent layer.

What is claimed is:  
     
         1 . An organic EL device comprising: 
 first and second electrodes;    an organic luminescent layer made of an organic luminescent material and interposed between the first and second electrodes; and    a protective layer disposed on the first electrode to cover the organic luminescent layer, the protective layer being formed by an atomic layer epitaxy method.    
     
     
         2 . The organic EL device of    claim 1   , further comprising a resin film disposed on the protective layer to protect the protective layer.  
     
     
         3 . The organic EL device of    claim 1   , wherein a formation temperature of the protective layer by the atomic layer epitaxy method is equal to or lower than a glass transition point of the organic luminescent material.  
     
     
         4 . The organic EL device of    claim 1   , wherein the protective layer is composed of a first layer and a second layer having internal stresses different from each other.  
     
     
         5 . The organic EL device of    claim 4   , wherein the first layer and the second layer are formed by the atomic layer epitaxy method, respectively, under forming conditions different from each other to have the internal stresses different from each other.  
     
     
         6 . The organic EL device of    claim 1   , wherein the protective layer contains a stress relaxing component for relaxing a stress produced in the protective layer.  
     
     
         7 . The organic EL device of    claim 6   , wherein: 
 the protective layer is composed of a stress relaxing layer and a non-stress relaxing layer; and    the stress relaxing component is contained only in the stress relaxing layer.    
     
     
         8 . The organic EL device of    claim 6   , wherein the protective layer is formed by the atomic layer epitaxy method using a source material gas for constituting the protective layer and a stress relaxing gas containing an element that acts as the stress relaxing component in the protective layer.  
     
     
         9 . The organic EL device of    claim 8   , wherein the stress relaxing gas contains a nitrogen compound.  
     
     
         10 . The organic EL device of    claim 1   , wherein the protective layer is composed of a first layer formed by the atomic layer epitaxy method, and a second layer formed by a method except the atomic layer epitaxy method.  
     
     
         11 . The organic EL device of    claim 10   , wherein 
 the second layer is disposed immediately on the first electrode in contact with the first electrode; and    the first layer is disposed on the second layer.    
     
     
         12 . The organic EL device of    claim 10   , wherein; 
 the first layer is disposed immediately on the first electrode in contact with the first electrode; and    the second layer is disposed on the first layer.    
     
     
         13 . The organic EL device of    claim 10   , wherein the method except the atomic layer epitaxy method is a CVD method.  
     
     
         14 . The organic EL device of    claim 10   , wherein the first layer and the second layer are made of alumina.  
     
     
         15 . A method for manufacturing an organic EL device, comprising: 
 preparing a luminescent structure composed of a pair of electrodes, and an organic luminescent material disposed between the pair of electrode; and    forming a protective layer by an ALE method on a surface of the luminescent structure to cover the organic luminescent material.    
     
     
         16 . The method of    claim 15   , wherein the protective layer is formed by the ALE method at a temperature equal to or lower than a glass transition point of the organic luminescent material.  
     
     
         17 . The method of    claim 15   , wherein the protective layer is formed by: 
 forming a first layer on the surface of the luminescent structure; and    forming a second layer on the first layer,    wherein the first layer and the second layer are formed to have internal stresses different from each other.    
     
     
         18 . The method of    claim 17   , wherein the first layer has a crystallinity different from that of the second layer so that the internal stresses of the first layer and the second layer are different from each other.  
     
     
         19 . The method of    claim 17   , wherein: 
 the first layer and the second layer are made of an identical compound with each other; and    only one of the first layer and the second layer contains an element except elements constituting the compound to thereby have the internal stress smaller than that of another one of the first layer and the second layer.    
     
     
         20 . The method of    claim 17   , wherein: 
 one of the first layer and the second layer is formed by the ALE method; and    another one of the first layer and the second layer is formed by a method other than the ALE method.