Patent ID: 8071985

Claim:
A display device comprising: a substrate; a thin film transistor disposed on the substrate and configured to receive a display signal, the thin film transistor comprising: (a) a light-shielding layer disposed on the substrate; (b) a buffer film disposed on the light shielding layer, the buffer film having: (i) an opening; (ii) a bottom portion; (iii) a top portion; and (iv) a slant portion such that the bottom portion is smaller than the top portion; (c) a first portion of a polysilicon layer disposed on the buffer film, the first portion of the polysilicon layer having: (i) a surface; (ii) protrusions formed on the surface; and (iii) a first grain size; (d) a gate insulation film disposed on the first portion of the polysilicon layer, the gate insulation film covering the protrusions; and (e) a gate electrode disposed on the gate insulation film; and a storage capacitor disposed on the substrate and configured to store the display signal supplied by the thin film transistor, the storage capacitor comprising: (a) a lower storage capacitor electrode disposed on the substrate; (b) a lower storage capacitor film disposed pn the buffer film, the lower storage capacitor film being: (i) in contact with the lower storage capacitor electrode through the opening in the buffer film; and (ii) thinner than the buffer film; (c) a middle storage capacitor electrode disposed on the lower storage capacitor film, the middle storage capacitor: (i) being formed of a second portion of the polysilicon layer; (ii) having an edge portion; (iii) being larger than the bottom portion of the buffer film such that the edge portion is located over the slant portion of the buffer film; and (iv) having a second grain size which is smaller than the first grain size; (d) an upper storage capacitor film disposed on the middle storage capacitor electrode; and (e) an upper storage capacitor electrode disposed on the upper storage capacitor film.