Display panel and method for manufacturing the same

Abstract

A display panel includes an insulating substrate, a pixel portion, a gate driver circuit portion, and a drain driver circuit portion. The pixel portion, gate driver circuit portion and drain driver circuit portion are formed out of thin film transistors on the insulating substrate, and the thin film transistors forming the pixel portion, the gate driver circuit portion and the drain driver circuit portion are built in poly-crystalline silicon films, respectively. Each of the poly-crystalline silicon films forming the thin film transistors is formed out of one of at least two kinds of crystal grains different in grain size.

1 . A display panel comprising: 
 an insulating substrate on which an amorphous silicon film is formed, said amorphous silicon being irradiated with a laser beam to thereby be transformed into a poly-crystalline silicon film; and    thin film transistors built in said poly-crystalline silicon film, and located in a driver circuit portion and a pixel portion;    wherein both a maximum value of surface roughness of said poly-crystalline silicon film forming said thin film transistors in said driver circuit portion and a maximum value of surface roughness of said poly-crystalline film forming said thin film transistors in said pixel portion are not higher than 30 nm.    
   
   
       2 . A display panel comprising: 
 an insulating substrate;    a pixel portion;    a gate driver circuit portion; and    a drain driver circuit portion;    wherein said pixel portion, said gate driver circuit portion and said drain driver circuit portion are formed out of thin film transistors on said insulating substrate; and    wherein said thin film transistors forming said pixel portion, said gate driver circuit portion and said drain driver circuit portion are built in poly-crystalline silicon films respectively, and each of said poly-crystalline silicon films forming said thin film transistors is formed out of one of at least two kinds of crystal grains different in grain size.    
   
   
       3 . A display panel according to  claim 2 , wherein said poly-crystalline silicon film forming said thin film transistors in said pixel portion is a fine grain crystalline film, while said poly-crystalline silicon films forming said thin film transistors in said gate driver circuit portion and said drain driver circuit portion are large-grain-size belt-like poly-crystalline films.  
   
   
       4 . A display panel according to  claim 2 , wherein said poly-crystalline silicon films forming said thin film transistors in said pixel portion and said gate driver circuit portion are fine grain crystalline films, while said poly-crystalline silicon film forming said thin film transistors in said drain driver circuit portion is a large-grain-size belt-like poly-crystalline film.  
   
   
       5 . A display panel according to  claim 2 , wherein each of said poly-crystalline silicon films forming said thin film transistors in said pixel portion, said gate driver circuit portion and said drain driver circuit portion is formed out of one of at least two kinds of poly-crystalline silicon films different in mobility.  
   
   
       6 . A display panel according to  claim 2 , wherein said poly-crystalline silicon film forming said thin film transistors in said pixel portion has a mobility of 10-200 cm 2 /Vs, and said poly-crystalline silicon films forming said thin film transistors in said gate driver circuit portion and said drain driver circuit portion have a mobility not lower than 200 cm 2 /Vs.  
   
   
       7 . A display panel according to  claim 2 , wherein said poly-crystalline silicon films forming said thin film transistors in said pixel portion and said gate driver circuit portion have a mobility of 10-200 cm 2 /Vs, and said poly-crystalline silicon film forming said thin film transistors in said drain driver circuit portion has a mobility not lower than 200 cm 2 /Vs.  
   
   
       8 . A display panel according to  claim 2 , wherein said poly-crystalline silicon film forming said thin film transistors in said pixel portion has a mobility of 10-200 cm 2 /Vs, said poly-crystalline silicon film forming said thin film transistors in said gate driver circuit portion has a mobility of 200-400 cm 2 /Vs, and said poly-crystalline silicon film forming said thin film transistors in said drain driver circuit portion has a mobility not lower than 400 cm 2 /Vs.