Organic electroluminescent display device and chemical compounds for liquid crystals

Abstract

The new organic electroluminescent display device has a carrier-transporting layer 3 and/or an organic luminous layer 4 composed of a nematic liquid crystal or a liquid crystal dispersing a carrier-transporting low-molecule therein. When the organic luminous layer 4 is to be bestowed with faculty as a liquid crystal, it is made of a nematic liquid crystal. Both the carrier-transporting layer 3 and the organic luminous layer 4 may be bestowed with faculty as a liquid crystal. Since the liquid crystal is incorporated in the carrier-transporting layer 3 and/or the organic luminous layer 4, the display device can be driven as a liquid crystal display device in a dark place by charging with a voltage lower than a light emission initiating potential. Of course, it is driven as an electroluminescent display device when it is charged with a voltage higher than the light emission initiating potential. Use of an electroluminescent liquid crystal as an organic luminous layer enables omission of a carrier-transporting layer 3.

1 . An organic electroluminescent display device involving at least one carrier-transporting layer composed of a liquid crystal substance and at least one organic luminous layer sandwiched between a transparent electrode and a backside electrode each held in parallel to the other, 
 wherein said display device is driven as a liquid crystal display device or as an electroluminescent display device in response to magnitude of an applied voltage.    
     
     
         2 . The organic electroluminescent display device according to    claim 1   , wherein the organic luminous layer is made of a polymer.  
     
     
         3 . The organic electroluminescent display device according to    claim 1   , wherein the organic luminous layer is made of a low molecule-dispersed polymer.  
     
     
         4 . The organic electroluminescent display device according to    claim 1   , wherein the organic luminous layer is a bilayer of a polymer and a monomer.  
     
     
         5 . The organic electroluminescent display device according to    claim 1   , wherein the carrier-transporting layer is a nematic liquid crystal layer.  
     
     
         6 . The organic electroluminescent display device according to    claim 1   , wherein the carrier-transporting layer is a liquid crystal layer dispersing a low-molecular carrier-transporting substance therein.  
     
     
         7 . The organic electroluminescent display device according to    claim 6   , wherein the liquid crystal layer contains two or more of different organic compounds.  
     
     
         8 . The organic electroluminescent display device according to    claim 7   , wherein the organic compound is Ir(ppy) 3  having a formula of:  
       
         
           
           
               
               
           
         
       
     
     
         9 . An organic electroluminescent display device involving at least one carrier-transporting layer and at least one organic luminous layer composed of a liquid crystal substance sandwiched between a transparent electrode and a backside electrode held in parallel to said transparent electrode, 
 wherein said display device is driven as a liquid crystal display device or as an electroluminescent display device in response to magnitude of an applied voltage.    
     
     
         10 . The organic electroluminescent display device according to    claim 9   , wherein the carrier-transporting layer is made of a polymer.  
     
     
         11 . The organic electroluminescent display device according to    claim 9   , wherein the carrier-transporting layer is made of a low molecule-dispersed polymer.  
     
     
         12 . The organic electroluminescent display device according to    claim 9   , wherein the carrier-transporting layer is a bilayer of a polymer and a monomer.  
     
     
         13 . The organic electroluminescent display device according to    claim 9   , wherein the organic luminous layer is a nematic liquid crystal layer.  
     
     
         14 . The organic electroluminescent display device according to    claim 13   , wherein the liquid crystal layer contains two or more of different organic compounds.  
     
     
         15 . The organic electroluminescent display device according to    claim 14   , wherein the organic compound is Ir(ppy) 3  having a formula of:  
       
         
           
           
               
               
           
         
       
     
     
         16 . An organic electroluminescent display device involving an organic luminous layer and a carrier-transporting layer, either one or both of which contains a liquid crystal, sandwiched between a transparent electrode and a backside electrode, 
 wherein said display device is driven as a liquid crystal display device or as an electroluminescent display device in response to magnitude of an applied voltage.    
     
     
         17 . The organic electroluminescent display device according to    claim 16   , wherein the liquid crystal contains two or more of different organic compounds.  
     
     
         18 . The organic electroluminescent display device according to    claim 17   , wherein the organic compound is Ir(ppy) 3  having a formula of:  
       
         
           
           
               
               
           
         
       
     
     
         19 . An organic electroluminescent display device involving at least one organic luminous layer comprising an electroluminescent liquid crystal sandwiched between a transparent electrode and a backside electrode each held in parallel to the other, 
 wherein said display device is driven as a liquid crystal display device or as an electroluminescent display device in response to magnitude of an applied voltage.    
     
     
         20 . An electroluminescent liquid crystal consisting of a chemical compound having a general constitutional formula of:  
       
         
           
           
               
               
           
         
         wherein R 1  is a straight-chained alkyl group containing 1-20 carbon atoms, R 2  to R 9  is individually hydrogen or an alkyl group containing 1-3 carbon atoms, and Ar 1  is a substituted or non-substituted aryl group containing 6-14 carbon atoms.  
       
     
     
         21 . An electroluminescent liquid crystal consisting of a chemical compound having a general constitutional formula of:  
       
         
           
           
               
               
           
         
         wherein R 10  and R 11  are individually straight-chained alkyl groups containing 1-20 carbon atoms, and Ar 2  and Ar 3  are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms.  
       
     
     
         22 . An electroluminescent liquid crystal consisting of a chemical compound having a general constitutional formula of:  
       
         
           
           
               
               
           
         
         wherein R 12  is a straight-chained alkyl group containing 1-20 carbon atoms, and R 13  to R 17  are individually hydrogen or alkyl groups containing 1-3 carbon atoms.  
       
     
     
         23 . An electroluminescent liquid crystal consisting of a chemical compound having a general constitutional formula of:  
       R 18 —Ar 4 —Ar 5 —O—R 19    wherein R 18  and R 19  are individually straight-chained alkyl groups containing 1-20 carbon atoms, and Ar 4  and Ar 5  are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms.    
     
     
         24 . An electroluminescent liquid crystal consisting of a chemical compound having a general constitutional formula of:  
       
         
           
           
               
               
           
         
         wherein R 20  is a straight-chained alkyl group containing 1-20 carbon atoms, and Ar 6  to Ar 10  are individually substituted or non-substituted aryl groups containing 6-14 carbon atoms.