Method of fabricating an organic electroluminescent device

Abstract

The present invention provides a novel organic electroluminescent device having an optical interference member which reduces the overall reflectance from the device. The invention is particularly suited to current-driven organic displays having an anode, an electroluminescent layer and a cathode, where at least one optical interference member is placed between two of the layers and thus forms part of the electrical circuit required to excite the display. The optical interference member is chosen to have a thickness which causes at least some destructive optical interference of ambient light incident on the display. In addition, the material(s) of the optical interference member are chosen to have a work function which is compatible with the highest occupied molecular orbital, or the lowest unoccupied molecular orbital of the electroluminescent layer, depending on the location of the optical interference member in relation to the anode, cathode and electroluminescent layer. The appropriate selection of material can ensure proper current flow the device, thus reducing the likelihood of electrical breakdown of the organic electroluminescent layer, and improving the overall energy efficiency of the device.

29 . A method of fabricating an electroluminescent device for displaying an image to a viewer in front of said device, sing the steps of: 
 depositing an anode layer onto a substrate;    depositing an organic electroluminescent layer onto said anode layer, said electroluminescent layer having a first energy characteristic associated with anode  4  side, and a second energy characteristic associated with a cathode side: 
 depositing an optical interference member onto said electroluminescent layer, said optical interference member for reducing the reflectance of ambient light towards said viewer, said optical interference member having a work function substantially equal to said second energy characteristic;  
 depositing a cathode layer onto ad optical interference member; and  
 sealing said device.  
   
     
     
         30 . A method of assembling an electroluminescent device for displaying an image to a viewer in font of said device, comprising the steps of: 
 depositing an anode layer onto a substrate;    depositing an optical interference member onto sad anode  4  layer; said optical interference member for reducing the reflectance of ambient light towards said viewer, said optical interference member having a work function;    depositing an organic electroluminescent layer onto said anode layer, said electroluminescent layer having an energy characteristics being the amount of energy required to extract an elect from said electroluminescent layer, said energy characteristic being substantially equal to said work function;    depositing a cathode layer onto said electroluminescent layer, and    sealing said device.