Electronic paper display device, manufacturing method and driving method thereof

Abstract

An electronic paper display device, a manufacturing method and a driving method thereof are disclosed. Micro protrusion members are formed at electrodes or at insulating layers. Consequently, the electrophoretic particles are prevented from being securely attached to an upper or the lower structure, and therefore, the quality of pictures is improved, and the contrast ratio of the pictures is increased. The relative sizes and the injection amounts of two kinds of electrophoretic particles are changed such that the relative sizes and the injection amounts of the electrophoretic particles are different from each other. Consequently, the driving voltage is lowered by excessively electrifying the electrophoretic particles of one kind. Protrusions are formed at the corresponding electrode such that a relatively large electric field is distributed around the electrode at which electrophoretic particles are located in the initial stage of voltage application. Consequently, the electrophoretic particles are easily separated from the electrode and moved even at low driving voltage. As such, the voltage level of the driving voltage pulse is lowered. Consequently, it is possible to further increase the response speed of the driving devices and to lower the internal voltage of the devices, thereby reducing the costs related to the driving devices.

1 . An electronic paper display device comprising:
 a first substrate and a second substrate, which are disposed opposite to each other while the first substrate and the second substrate are spaced apart from each other;   a plurality of first electrodes and a plurality of second electrodes formed at the bottom of the first substrate and at the top of the second substrate, respectively;   a plurality of barrier ribs disposed between the first substrate and the second substrate to form a plurality of cells; and   first and second electrophoretic particles injected in the cells, the first and second electrophoretic particles having different particle amounts.   
   
   
       2 . The electronic paper display device according to  claim 1 , wherein the first electrophoretic particles, the particle amount of which is large, are white electrophoretic particles. 
   
   
       3 . The electronic paper display device according to  claim 1 , wherein the second electrophoretic particles, the particle amount of which is large, are black electrophoretic particles. 
   
   
       4 . The electronic paper display device according to  claim 1  wherein the weight ratio of the electrophoretic particles having the large particle amount to the electrophoretic particles having the small particle amount is 1.2:1 to 5:1. 
   
   
       5 . The electronic paper display device according to  claim 1 , wherein the first and second electrophoretic particles have the same particle diameter. 
   
   
       6 . The electronic paper display device according to  claim 1 , wherein the electrophoretic particles having the large particle injection amount has a particle diameter less than that of the electrophoretic particles having the small particle injection amount. 
   
   
       7 . The electronic paper display device according to  claim 1 , wherein the first and second electrophoretic particles are dry-type electrophoretic particles. 
   
   
       8 . The electronic paper display device according to  claim 1 , further comprising:
 insulating layers to cover the first and second electrodes, respectively.